Sample records for examination interactive simulator

  1. Applying Positioning Theory to Examine Interactions between Simulated Patients and Medical Students: A Narrative Analysis (United States)

    Sargeant, Sally; McLean, Michelle; Green, Patricia; Johnson, Patricia


    In their journey to becoming doctors, students engage with a range of teachers and trainers. Among these are simulated patients (SPs), who, through role-playing, assist students to develop their communication and physical examination skills, in contexts of formative and summative assessments. This paper explores the teaching and learning…

  2. Applying positioning theory to examine interactions between simulated patients and medical students: a narrative analysis. (United States)

    Sargeant, Sally; McLean, Michelle; Green, Patricia; Johnson, Patricia


    In their journey to becoming doctors, students engage with a range of teachers and trainers. Among these are simulated patients (SPs), who, through role-playing, assist students to develop their communication and physical examination skills, in contexts of formative and summative assessments. This paper explores the teaching and learning relationship between medical students and SPs, and considers how this might affect feedback and assessment. 14 SPs were interviewed on the subject of medical students' professional identity development in 2014. Data were examined using narrative analysis in conjunction with positioning theory to identify the positions that SPs assigned to themselves and to students. Narrative analysis yielded three interpretative positioning themes: Occupational, familial and cultural and discursive and embodied positioning. The interview process revealed that SPs adopt different positions intra-and interpersonally. SPs appear to hold dissonant perceptions of students in terms relating to their emerging professional identities, which may confound assessment and feedback. Training should include reflections on the SP/student relationship to uncover potential biases and positions, giving SPs the opportunity to reflect on and manage their individual and occupational selves.

  3. Interactive CFD simulations


    Duque Lombana, Juan Fernando


    This project is about the development of an implementable Interactive Computer Fluid Dynamics methodology -- The range of this work begins with an overview of the current status of computational fluid dynamics simulation software and methodologies, continues with an introduction to what interactive and interactivity mean, develops an all original interactive CFD methodology to follow for the solution of fluid scenarios and finally, the description of the implementation of an interactive solve...

  4. Interactive Foresight Simulation

    DEFF Research Database (Denmark)

    Hansen, Mette Sanne; Rasmussen, Lauge Baungaard; Jacobsen, Peter


    The Combined Simulation Approach (CSA) is a way to evaluate risks and address potential unforeseen problems in a more interactive way than what is often observed in practice in companies or sectors. The approach is based on a combination of scenario analysis and discrete-event computer simulation...

  5. Structure, dynamics, and interaction of Mycobacterium tuberculosis (Mtb) DprE1 and DprE2 examined by molecular modeling, simulation, and electrostatic studies. (United States)

    Bhutani, Isha; Loharch, Saurabh; Gupta, Pawan; Madathil, Rethi; Parkesh, Raman


    The enzymes decaprenylphosphoryl-β-D-ribose oxidase (DprE1) and decaprenylphosphoryl-β-D-ribose-2-epimerase (DprE2) catalyze epimerization of decaprenylphosporyl ribose (DPR) todecaprenylphosporyl arabinose (DPA) and are critical for the survival of Mtb. Crystal structures of DprE1 so far reported display significant disordered regions and no structural information is known for DprE2. We used homology modeling, protein threading, molecular docking and dynamics studies to investigate the structural and dynamic features of Mtb DprE1 and DprE2 and DprE1-DprE2 complex. A three-dimensional model for DprE2 was generated using the threading approach coupled with ab initio modeling. A 50 ns simulation of DprE1 and DprE2 revealed the overall stability of the structures. Principal Component Analysis (PCA) demonstrated the convergence of sampling in both DprE1 and DprE2. In DprE1, residues in the 269-330 area showed considerable fluctuation in agreement with the regions of disorder observed in the reported crystal structures. In DprE2, large fluctuations were detected in residues 95-113, 146-157, and 197-226. The study combined docking and MD simulation studies to map and characterize the key residues involved in DprE1-DprE2 interaction. A 60 ns MD simulation for DprE1-DprE2 complex was also performed. Analysis of data revealed that the docked complex is stabilized by H-bonding, hydrophobic and ionic interactions. The key residues of DprE1 involved in DprE1-DprE2 interactions belong to the disordered region. We also examined the docked complex of DprE1-BTZ043 to investigate the binding pocket of DprE1 and its interactions with the inhibitor BTZ043. In summary, we hypothesize that DprE1-DprE2 interaction is crucial for the synthesis of DPA and DprE1-DprE2 complex may be a new therapeutic target amenable to pharmacological validation. The findings have important implications in tuberculosis (TB) drug discovery and will facilitate drug development efforts against TB.

  6. Interactive Dynamic-System Simulation

    CERN Document Server

    Korn, Granino A


    Showing you how to use personal computers for modeling and simulation, Interactive Dynamic-System Simulation, Second Edition provides a practical tutorial on interactive dynamic-system modeling and simulation. It discusses how to effectively simulate dynamical systems, such as aerospace vehicles, power plants, chemical processes, control systems, and physiological systems. Written by a pioneer in simulation, the book introduces dynamic-system models and explains how software for solving differential equations works. After demonstrating real simulation programs with simple examples, the author

  7. Simulation of interactive games


    Heiberg, Fredrik


    Interactive online games are increasingly popular in today's society, and the industry is growing fast. Games take place in a virtual world and involve interaction with other players. Some online games connect millions of people, and the game studios enjoy enormous revenue utilising different business models. The interactive game market has changed a lot over the years, and player demands have increased concerning functionality, content, and price. As a result, the costs related to developmen...

  8. An Interactive Approach to Examination Timetabling. (United States)

    Colijn, Anton; And Others


    Microcomputer-managed examination scheduling at the University of Calgary (Canada) has two stages. The first uses mathematical methods to create a timetable that is conflict-free, uses a minimum number of periods, and minimizes the number of students with multiple exams in one day. An interactive stage allows the examination officer to accommodate…

  9. Interactive Simulations of Biohybrid Systems

    Directory of Open Access Journals (Sweden)

    Sebastian Albrecht von Mammen


    Full Text Available In this article, we present approaches to interactive simulations of biohybrid systems. These simulations are comprised of two major computational components: (1 agent-based developmental models that retrace organismal growth and unfolding of technical scaffoldings and (2 interfaces to explore these models interactively. Simulations of biohybrid systems allow us to fast forward and experience their evolution over time based on our design decisions involving the choice, configuration and initial states of the deployed biological and robotic actors as well as their interplay with the environment. We briefly introduce the concept of swarm grammars, an agent-based extension of L-systems for retracing growth processes and structural artifacts. Next, we review an early augmented reality prototype for designing and projecting biohybrid system simulations into real space. In addition to models that retrace plant behaviors, we specify swarm grammar agents to braid structures in a self-organizing manner. Based on this model, both robotic and plant-driven braiding processes can be experienced and explored in virtual worlds. We present an according user interface for use in virtual reality. As we present interactive models concerning rather diverse description levels, we only ensured their principal capacity for interaction but did not consider efficiency analyzes beyond prototypic operation. We conclude this article with an outlook on future works on melding reality and virtuality to drive the design and deployment of biohybrid systems.

  10. Examining flow-flame interaction and the characteristic stretch rate in vortex-driven combustion dynamics using PIV and numerical simulation

    KAUST Repository

    Hong, Seunghyuck


    In this paper, we experimentally investigate the combustion dynamics in lean premixed flames in a laboratory scale backward-facing step combustor in which flame-vortex driven dynamics are observed. A series of tests was conducted using propane/hydrogen/air mixtures for various mixture compositions at the inlet temperature ranging from 300K to 500K and at atmospheric pressure. Pressure measurements and high speed particle image velocimetry (PIV) are used to generate pressure response curves and phase-averaged vorticity and streamlines as well as the instantaneous flame front, respectively, which describe unsteady flame and flow dynamics in each operating regime. This work was motivated in part by our earlier study where we showed that the strained flame consumption speed Sc can be used to collapse the pressure response curves over a wide range of operating conditions. In previous studies, the stretch rate at which Sc was computed was determined by trial and error. In this study, flame stretch is estimated using the instantaneous flame front and velocity field from the PIV measurement. Independently, we also use computed strained flame speed and the experimental data to determine the characteristic values of stretch rate near the mode transition points at which the flame configuration changes. We show that a common value of the characteristic stretch rate exists across all the flame configurations. The consumption speed computed at the characteristic stretch rate captures the impact of different operating parameters on the combustor dynamics. These results suggest that the unsteady interactions between the turbulent flow and the flame dynamics can be encapsulated in the characteristic stretch rate, which governs the critical flame speed at the mode transitions and thereby plays an important role in determining the stability characteristics of the combustor. © 2013 The Combustion Institute.

  11. Examining Interactivity in Synchronous Virtual Classrooms (United States)

    Martin, Florence; Parker, Michele A.; Deale, Deborah F.


    Interaction is crucial to student satisfaction in online courses. Adding synchronous components (virtual classroom technologies) to online courses can facilitate interaction. In this study, interaction within a synchronous virtual classroom was investigated by surveying 21 graduate students in an instructional technology program in the…

  12. Toward an Ontology of Simulated Social Interaction

    DEFF Research Database (Denmark)

    Seibt, Johanna


    The paper develops a general conceptual framework for the ontological classification of human-robot interaction. After arguing against fictionalist interpretations of human-robot interactions, I present five notions of simulation or partial realization, formally defined in terms of relationships......, anthropology, and linguistics. The classificatory framework developed (SISI) thus represents the field of possible simulated social interactions. SISI can be used to clarify which conceptual and empirical grounds we can draw on to evaluate capacities and affordances of robots for social interaction...

  13. Salesperson Ethics: An Interactive Computer Simulation (United States)

    Castleberry, Stephen


    A new interactive computer simulation designed to teach sales ethics is described. Simulation learner objectives include gaining a better understanding of legal issues in selling; realizing that ethical dilemmas do arise in selling; realizing the need to be honest when selling; seeing that there are conflicting demands from a salesperson's…

  14. New logistics protocols for distributed interactive simulation (United States)

    Taylor, Darrin; Morrison, John; Katz, Warren; Felton, Erik; Herman, Deborah A.


    In today's environment, the transportation and maintenance of military forces is nearly as important as combat operations. Rapid deployment to regions of low-intensity conflict will become a very common training scenario for the U.S. military. Thus it is desirable to apply distributed simulation technology to train logistics personnel in their combat support roles. Currently, distributed interactive simulation (DIS) only contains rudimentary logistics protocols. This paper introduces new protocols designed to handle the logistics problem. The Newtonian protocol takes a physics-based approach to modeling interactions on the simulation network. This protocol consists of a family of protocol data units (PDUs) which are used to communicate forces in different circumstances. The protocol implements a small set of physical relations. This represents a flexible and general mechanism to describe battlefield interactions between network entities. The migratory object protocol (MOP) family addresses the transfer of control. General mechanisms provide the means to simulate resupply, repair, and maintenance of entities at any level of abstraction (individual soldier to division). It can also increase the fidelity of mine laying, enable handover of weapons for terminal guidance, allow for the distribution of aggregate-level simulation entities, provide capabilities for the simulation of personnel, etc.

  15. Local simulation algorithms for Coulombic interactions

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 64; Issue 6. Local simulation algorithms for Coulombic interactions. L Leverel F Alet J Rottler A C Maggs. Invited Talks:- Topic 7. Soft condensed matter (colloids, polymers, liquid crystals, microemulsions, foams, membranes, etc.) Volume 64 Issue 6 June 2005 pp ...

  16. Interactive Mathematica Simulations in Chemical Engineering Courses (United States)

    Falconer, John L.; Nicodemus, Garret D.


    Interactive Mathematica simulations with graphical displays of system behavior are an excellent addition to chemical engineering courses. The Manipulate command in Mathematica creates on-screen controls that allow users to change system variables and see the graphical output almost instantaneously. They can be used both in and outside class. More…

  17. Interactive visualization to advance earthquake simulation (United States)

    Kellogg, L.H.; Bawden, G.W.; Bernardin, T.; Billen, M.; Cowgill, E.; Hamann, B.; Jadamec, M.; Kreylos, O.; Staadt, O.; Sumner, D.


    The geological sciences are challenged to manage and interpret increasing volumes of data as observations and simulations increase in size and complexity. For example, simulations of earthquake-related processes typically generate complex, time-varying data sets in two or more dimensions. To facilitate interpretation and analysis of these data sets, evaluate the underlying models, and to drive future calculations, we have developed methods of interactive visualization with a special focus on using immersive virtual reality (VR) environments to interact with models of Earth's surface and interior. Virtual mapping tools allow virtual "field studies" in inaccessible regions. Interactive tools allow us to manipulate shapes in order to construct models of geological features for geodynamic models, while feature extraction tools support quantitative measurement of structures that emerge from numerical simulation or field observations, thereby enabling us to improve our interpretation of the dynamical processes that drive earthquakes. VR has traditionally been used primarily as a presentation tool, albeit with active navigation through data. Reaping the full intellectual benefits of immersive VR as a tool for scientific analysis requires building on the method's strengths, that is, using both 3D perception and interaction with observed or simulated data. This approach also takes advantage of the specialized skills of geological scientists who are trained to interpret, the often limited, geological and geophysical data available from field observations. ?? Birkhaueser 2008.

  18. Simulation of Gas-Surface Dynamical Interactions (United States)


    surface. The substrate with lattice constant a is represented in a simple ball and spring picture. on the particular problem. Time-independent...παvwell , (26) Simulation of Gas-Surface Dynamical Interactions 4 - 10 RTO-EN-AVT-142 g E ad v mvc ∆ v’well vc cM Figure 4

  19. Interactive Heat Transfer Simulations for Everyone (United States)

    Xie, Charles


    Heat transfer is widely taught in secondary Earth science and physics. Researchers have identified many misconceptions related to heat and temperature. These misconceptions primarily stem from hunches developed in everyday life (though the confusions in terminology often worsen them). Interactive computer simulations that visualize thermal energy,…

  20. Interaction of simulated actors with the environment

    NARCIS (Netherlands)

    Gazendam, H.W.M.; Charrel, PJ; Galarreta, D


    The current chapter explores the possibilities of an improvement of the interaction of an ACT-R actor with its environment including other actors. This is done in the framework of a project aiming at a multi-actor simulation enviromnent based on the ACT-R architecture. Two objections against

  1. Interactive methods for exploring particle simulation data

    Energy Technology Data Exchange (ETDEWEB)

    Co, Christopher S.; Friedman, Alex; Grote, David P.; Vay, Jean-Luc; Bethel, E. Wes; Joy, Kenneth I.


    In this work, we visualize high-dimensional particle simulation data using a suite of scatter plot-based visualizations coupled with interactive selection tools. We use traditional 2D and 3D projection scatter plots as well as a novel oriented disk rendering style to convey various information about the data. Interactive selection tools allow physicists to manually classify ''interesting'' sets of particles that are highlighted across multiple, linked views of the data. The power of our application is the ability to correspond new visual representations of the simulation data with traditional, well understood visualizations. This approach supports the interactive exploration of the high-dimensional space while promoting discovery of new particle behavior.

  2. Examiner and simulated patient ratings of empathy in medical student final year clinical examination: are they useful? (United States)

    Wright, Barry; McKendree, Jean; Morgan, Lewys; Allgar, Victoria L; Brown, Andrew


    Many medical schools state that empathy is important and have curricular learning outcomes covering its teaching. It is thought to be useful in team-working, good bedside manner, patient perspective taking, and improved patient care. Given this, one might expect it to be measured in assessment processes. Despite this, there is relatively little literature exploring how measures of empathy in final clinical examinations in medical school map onto other examination scores. Little is known about simulated patient (actors) rating of empathy in examinations in terms of inter-rater reliability compared with clinical assessors or correlation with overall examination results. Examiners in final year clinical assessments in one UK medical school rated 133 students on five constructs in Objective Structured Long Examination Record (OSLER) with real patients: gathering information, physical examination, problem solving, managing the diagnosis, and relationship with the patient. Scores were based on a standardized well-established penalty point system. In separate Objective Structured Clinical Examination (OSCE) stations, different examiners used the same penalty point system to score performance in both interactional and procedural stations. In the four interaction-based OSCE stations, examiners and simulated patient actors also independently rated empathy of the students. The OSLER score, based on penalty points, had a correlation of -0.38 with independent ratings of empathy from the interactional OSCE stations. The intra-class correlation (a measure of inter-rater reliability) between the observing clinical tutor and ratings from simulated patients was 0.645 with very similar means. There was a significant difference between the empathy scores of the 94 students passing the first part of the sequential examination, based on combined OSCE and OSLER scores (which did not include the empathy scores), and 39 students with sufficient penalty points to trigger attendance for the

  3. Hybrid Simulation in Teaching Clinical Breast Examination to Medical Students. (United States)

    Nassif, Joseph; Sleiman, Abdul-Karim; Nassar, Anwar H; Naamani, Sima; Sharara-Chami, Rana


    Clinical breast examination (CBE) is traditionally taught to third-year medical students using a lecture and a tabletop breast model. The opportunity to clinically practice CBE depends on patient availability and willingness to be examined by students, especially in culturally sensitive environments. We propose the use of a hybrid simulation model consisting of a standardized patient (SP) wearing a silicone breast simulator jacket and hypothesize that this, compared to traditional teaching methods, would result in improved learning. Consenting third-year medical students (N = 82) at a university-affiliated tertiary care center were cluster-randomized into two groups: hybrid simulation (breast jacket + SP) and control (tabletop breast model). Students received the standard lecture by instructors blinded to the randomization, followed by randomization group-based learning and practice sessions. Two weeks later, participants were assessed in an Objective Structured Clinical Examination (OSCE), which included three stations with SPs blinded to the intervention. The SPs graded the students on CBE completeness, and students completed a self-assessment of their performance and confidence during the examination. CBE completeness scores did not differ between the two groups (p = 0.889). Hybrid simulation improved lesion identification grades (p simulation relieved the fear of missing a lesion on CBE (p = 0.043) and increased satisfaction with the teaching method among students (p = 0.002). As a novel educational tool, hybrid simulation improves the sensitivity of CBE performed by medical students without affecting its specificity. Hybrid simulation may play a role in increasing the confidence of medical students during CBE.

  4. Simulation of Light Antinucleus-Nucleus Interactions

    CERN Document Server

    Galoyan, A.


    Creations of light anti-nuclei (anti-deuterium, anti-tritium, anti-He3 and anti-He4) are observed by collaborations at the LHC and RHIC accelerators. Some cosmic ray experiments are aimed to find the anti-nuclei in cosmic rays. To support the experimental studies of the anti-nuclei a Monte Carlo simulation of anti-nuclei interactions with matter is implemented in the Geant4 toolkit. The implementation combines practically all known theoretical approaches to the problem of antinucleon-nucleon interactions.

  5. Interactive simulations for quantum key distribution (United States)

    Kohnle, Antje; Rizzoli, Aluna


    Secure communication protocols are becoming increasingly important, e.g. for internet-based communication. Quantum key distribution (QKD) allows two parties, commonly called Alice and Bob, to generate a secret sequence of 0s and 1s called a key that is only known to themselves. Classically, Alice and Bob could never be certain that their communication was not compromised by a malicious eavesdropper. Quantum mechanics however makes secure communication possible. The fundamental principle of quantum mechanics that taking a measurement perturbs the system (unless the measurement is compatible with the quantum state) also applies to an eavesdropper. Using appropriate protocols to create the key, Alice and Bob can detect the presence of an eavesdropper by errors in their measurements. As part of the QuVis Quantum Mechanics Visualisation Project, we have developed a suite of four interactive simulations that demonstrate the basic principles of three different QKD protocols. The simulations use either polarised photons or spin 1/2 particles as physical realisations. The simulations and accompanying activities are freely available for use online or download, and run on a wide range of devices including tablets and PCs. Evaluation with students over three years was used to refine the simulations and activities. Preliminary studies show that the refined simulations and activities help students learn the basic principles of QKD at both the introductory and advanced undergraduate levels.

  6. Dynamics simulations for engineering macromolecular interactions (United States)

    Robinson-Mosher, Avi; Shinar, Tamar; Silver, Pamela A.; Way, Jeffrey


    The predictable engineering of well-behaved transcriptional circuits is a central goal of synthetic biology. The artificial attachment of promoters to transcription factor genes usually results in noisy or chaotic behaviors, and such systems are unlikely to be useful in practical applications. Natural transcriptional regulation relies extensively on protein-protein interactions to insure tightly controlled behavior, but such tight control has been elusive in engineered systems. To help engineer protein-protein interactions, we have developed a molecular dynamics simulation framework that simplifies features of proteins moving by constrained Brownian motion, with the goal of performing long simulations. The behavior of a simulated protein system is determined by summation of forces that include a Brownian force, a drag force, excluded volume constraints, relative position constraints, and binding constraints that relate to experimentally determined on-rates and off-rates for chosen protein elements in a system. Proteins are abstracted as spheres. Binding surfaces are defined radially within a protein. Peptide linkers are abstracted as small protein-like spheres with rigid connections. To address whether our framework could generate useful predictions, we simulated the behavior of an engineered fusion protein consisting of two 20 000 Da proteins attached by flexible glycine/serine-type linkers. The two protein elements remained closely associated, as if constrained by a random walk in three dimensions of the peptide linker, as opposed to showing a distribution of distances expected if movement were dominated by Brownian motion of the protein domains only. We also simulated the behavior of fluorescent proteins tethered by a linker of varying length, compared the predicted Förster resonance energy transfer with previous experimental observations, and obtained a good correspondence. Finally, we simulated the binding behavior of a fusion of two ligands that could

  7. Interactive simulations for quantum key distribution

    CERN Document Server

    Kohnle, Antje


    Secure communication protocols are becoming increasingly important, e.g. for internet-based communication. Quantum key distribution allows two parties, commonly called Alice and Bob, to generate a secret sequence of 0s and 1s called a key that is only known to themselves. Classically, Alice and Bob could never be certain that their communication was not compromised by a malicious eavesdropper. Quantum mechanics however makes secure communication possible. The fundamental principle of quantum mechanics that taking a measurement perturbs the system (unless the measurement is compatible with the quantum state) also applies to an eavesdropper. Using appropriate protocols to create the key, Alice and Bob can detect the presence of an eavesdropper by errors in their measurements. As part of the QuVis Quantum Mechanics Visualization Project, we have developed a suite of four interactive simulations that demonstrate the basic principles of three different quantum key distribution protocols. The simulations use either...

  8. An Initial Examination for Verifying Separation Algorithms by Simulation (United States)

    White, Allan L.; Neogi, Natasha; Herencia-Zapana, Heber


    An open question in algorithms for aircraft is what can be validated by simulation where the simulation shows that the probability of undesirable events is below some given level at some confidence level. The problem is including enough realism to be convincing while retaining enough efficiency to run the large number of trials needed for high confidence. The paper first proposes a goal based on the number of flights per year in several regions. The paper examines the probabilistic interpretation of this goal and computes the number of trials needed to establish it at an equivalent confidence level. Since any simulation is likely to consider the algorithms for only one type of event and there are several types of events, the paper examines under what conditions this separate consideration is valid. This paper is an initial effort, and as such, it considers separation maneuvers, which are elementary but include numerous aspects of aircraft behavior. The scenario includes decisions under uncertainty since the position of each aircraft is only known to the other by broadcasting where GPS believes each aircraft to be (ADS-B). Each aircraft operates under feedback control with perturbations. It is shown that a scenario three or four orders of magnitude more complex is feasible. The question of what can be validated by simulation remains open, but there is reason to be optimistic.

  9. Simulation experiences of paramedic students: a cross-cultural examination

    Directory of Open Access Journals (Sweden)

    Williams B


    Full Text Available Brett Williams,1 Chloe Abel,1 Eihab Khasawneh,2 Linda Ross,1 Tracy Levett-Jones31Department of Community Emergency Health & Paramedic Practice, Monash University, Frankston, Victoria, Australia; 2Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan; 3School of Nursing and Midwifery, The University of Newcastle, Callaghan, New South Wales, AustraliaBackground: Simulation-based education is an important part of paramedic education and ­training. While accessing clinical placements that are adequate in quality and quantity continues to be challenging, simulation is being recognized by paramedic academics as a potential alternative. Examining students’ satisfaction of simulation, particularly cross-culturally is therefore important in providing feedback to academic teaching staff and the international paramedic community.Objective: This study aimed to compare simulation satisfaction among paramedic students from universities in Australia and Jordan.Methods: A cross-sectional study using a paper-based English version of the Satisfaction with Simulation Experience Scale was administered to paramedic students from all year levels.Results: A total of 511 students participated in this study; 306 students (60% from Australia (Monash University and 205 students (40% from Jordan (Jordan University of Science and Technology. There were statistically significant differences with large effect size noted in all three original factors between Australian and Jordanian students: debrief and feedback (mean =38.66 vs mean =34.15; P<0.001; d=0.86, clinical reasoning (mean =21.32 vs mean =18.28; P<0.001; d=0.90, and clinical learning (mean =17.59 vs mean =15.47; P<0.001; d=1.12.Conclusion: This study has demonstrated that simulation education is generally well received by students in Australia and Jordan although Australian students reported having higher satisfaction levels then their Jordanian counterparts. These results

  10. Simulating the Interactions Among Land Use, Transportation ... (United States)

    In most transportation studies, computer models that forecast travel behavior statistics for a future year use static projections of the spatial distribution of future population and employment growth as inputs. As a result, they are unable to account for the temporally dynamic and non-linear interactions among transportation, land use, and socioeconomic systems. System dynamics (SD) provides a common framework for modeling the complex interactions among transportation and other related systems. This study uses a SD model to simulate the cascading impacts of a proposed light rail transit (LRT) system in central North Carolina, USA. The Durham-Orange Light Rail Project (D-O LRP) SD model incorporates relationships among the land use, transportation, and economy sectors to simulate the complex feedbacks that give rise to the travel behavior changes forecasted by the region’s transportation model. This paper demonstrates the sensitivity of changes in travel behavior to the proposed LRT system and the assumptions that went into the transportation modeling, and compares those results to the impacts of an alternative fare-free transit system. SD models such as the D-O LRP SD model can complement transportation studies by providing valuable insight into the interdependent community systems that collectively contribute to travel behavior changes. Presented at the 35th International Conference of the System Dynamics Society in Cambridge, MA, July 18th, 2017

  11. Simulations of RNA interactions with monovalent ions. (United States)

    Chen, Alan A; Marucho, Marcelo; Baker, Nathan A; Pappu, Rohit V


    RNA folding and binding reactions are mediated by interactions with ions that make up the surrounding aqueous electrolytic milieu. Although Mg(2+) ions are often implicated as being crucial for RNA folding, it is known that folding is feasible in high concentrations of monovalent alkali-halide salts. Experiments have yielded important information regarding the salt dependence of RNA stability. Recent work has shown that molecular simulations based on explicit representations of solvent molecules and monovalent ions can also provide useful insights regarding the ionic atmospheres around model RNA systems. These insights can help rationalize intriguing observations regarding the dependence of RNA stability on cation type providing one pays attention to important considerations that go into the proper design of molecular simulations. These issues are discussed in detail and the methods are applied to an A-form RNA and B-form DNA sequence. The results of these simulations are compared to previous work on a kissing-loop system with analogous sequence. In particular, ionic atmospheres obtained from molecular simulations are compared to those obtained using the nonlinear Poisson Boltzmann model for continuum electrostatics for these three different nucleic acid systems. The comparisons indicate reasonable agreement in terms of coarse-grained observables such as the numbers of counterions accumulated around the solutes. However, details of the ionic atmospheres, captured in terms of spatial free energy density profiles, are quite different between the two approaches. These comparisons suggest the need for improvements in continuum models to capture sequence-specific effects, ion-ion correlation, and the effects of partial dehydration of ions. Copyright © 2009 Elsevier Inc. All rights reserved.

  12. Computer simulation of spacecraft/environment interaction

    CERN Document Server

    Krupnikov, K K; Mileev, V N; Novikov, L S; Sinolits, V V


    This report presents some examples of a computer simulation of spacecraft interaction with space environment. We analysed a set data on electron and ion fluxes measured in 1991-1994 on geostationary satellite GORIZONT-35. The influence of spacecraft eclipse and device eclipse by solar-cell panel on spacecraft charging was investigated. A simple method was developed for an estimation of spacecraft potentials in LEO. Effects of various particle flux impact and spacecraft orientation are discussed. A computer engineering model for a calculation of space radiation is presented. This model is used as a client/server model with WWW interface, including spacecraft model description and results representation based on the virtual reality markup language.

  13. How Guidance Affects Student Engagement with an Interactive Simulation (United States)

    Chamberlain, Julia M.; Lancaster, Kelly; Parson, Robert; Perkins, Katherine K.


    We studied how students engaged with an interactive simulation in a classroom setting and how that engagement was affected by the design of a guiding activity. Students (n = 210) completed a written activity using an interactive simulation in second semester undergraduate general chemistry recitations. The same simulation--PhET Interactive…

  14. Examining the usability of a virtual reality driving simulator. (United States)

    Schultheis, Maria T; Rebimbas, Jose; Mourant, Ronald; Millis, Scott R


    The current study examined specific aspects of usability of a newly developed VR driver rehabilitation (VR-DR) system. Measures of user feedback and user comfort were examined among 54 participants: 33 individuals with acquired brain injury (20 with traumatic brain injury and 13 with cerebral vascular accident) and 21 healthy controls. All participants were administered the VR-DR and completed the VR-DR User Feedback Questionnaire. To examine group differences, a one-way analysis of variance was performed, comparing the user feedback total score between the three groups. The results indicated that the two clinical populations (traumatic brain injury and cerebral vascular accident) varied from the nonclinical population (healthy controls). A standard multiple regression analysis revealed that age was the only significant participant factor that contributed to the differences in user feedback ratings. Finally, consistent across the three groups, a distinct relationship was found between the self-reported user rating and the onset of simulation sickness. The current findings indicate that individuals with traumatic brain injury and cerebral vascular accident provided less favorable user feedback ratings than healthy controls in the use of a new VR-DR system. This difference was not accounted for by differences in gender, education, or cognitive status and was only slightly accounted for by age. Delineating these various aspects of user feedback can assist in identifying potential confounds in VR-DR performance and help refine the application of the VR-DR for clinical decision making.

  15. Using Interactive Simulations in Assessment: The Use of Computer-Based Interactive Simulations in the Assessment of Statistical Concepts (United States)

    Neumann, David L.


    Interactive computer-based simulations have been applied in several contexts to teach statistical concepts in university level courses. In this report, the use of interactive simulations as part of summative assessment in a statistics course is described. Students accessed the simulations via the web and completed questions relating to the…

  16. Combining Interactive Thermodynamics Simulations with Screencasts and Conceptests (United States)

    Falconer, John L.


    More than 40 interactive "Mathematica" simulations were prepared for chemical engineering thermodynamics, screencasts were prepared that explain how to use each simulation, and more than 100 ConcepTests were prepared that utilize the simulations. They are located on The purposes of these simulations are to clarify…

  17. Examining classroom interactions related to difference in students' science achievement (United States)

    Zady, Madelon F.; Portes, Pedro R.; Ochs, V. Dan


    The current study examines the cognitive supports that underlie achievement in science by using a cultural historical framework (L. S. Vygotsky (1934/1986), Thought and Language, MIT Press, Cambridge, MA.) and the activity setting (AS) construct (R. G. Tharp & R. Gallimore (1988), Rousing minds to life: Teaching, learning and schooling in social context, Cambridge University Press, Cambridge, MA.) with its five features: personnel, motivations, scripts, task demands, and beliefs. Observations were made of the classrooms of seventh-grade science students, 32 of whom had participated in a prior achievement-related parent-child interaction or home study (P. R. Portes, M. F. Zady, & R. M. Dunham (1998), Journal of Genetic Psychology, 159, 163-178). The results of a quantitative analysis of classroom interaction showed two features of the AS: personnel and scripts. The qualitative field analysis generated four emergent phenomena related to the features of the AS that appeared to influence student opportunity for conceptual development. The emergent phenomenon were science activities, the building of learning, meaning in lessons, and the conflict over control. Lastly, the results of the two-part classroom study were compared to those of the home science AS of high and low achievers. Mismatches in the AS features in the science classroom may constrain the opportunity to learn. Educational implications are discussed.

  18. Development of a Simulated Environment for Human-Robot Interaction

    Directory of Open Access Journals (Sweden)

    Karsten Berns


    Full Text Available Human-robot interaction scenarios are extremely complicated and require precise definition of the environment variables for rigorously testing different aspects of robotic behavior. The environmental setup affects the behaviors of both the humans and the robots, as they respond differently under varying accoustic or lightning conditions. Moreover, conducting several experiments repeatedly with the humans as test subjects also causes behavioral changes in them and eventually the responses remain no longer similar to the already conducted experiments. Thus making it is impossible to perform interaction scenarios in a repeatable manner. Developing and using 3D simulations, where different parameters can be adjusted, is the most beneficial solution in such cases. This requires not only the development of different simulated robots but also the simulation of dynamic surroundings including the interaction partner. In this paper, we present a simulation framework that allows the simulation of human-robot interaction including the simulated interaction partner and its dynamics.

  19. Lattice-Boltzmann simulations of the electrophoretic stretching of polyelectrolytes: the importance of hydrodynamic interactions. (United States)

    Hickey, Owen A; Holm, Christian; Smiatek, Jens


    In this article we examine the electrophoretic stretching of polyelectrolytes between parallel uncharged plates using molecular dynamics simulations. We compare simulations where the fluid is modeled implicitly using a Langevin thermostat, which ignore hydrodynamic interactions, to simulations with an explicit lattice-Boltzmann fluid that take hydrodynamic interactions into account. The difference between simulations with and without hydrodynamic interactions is larger for longer polyelectrolytes, as one would expect. Furthermore, we present simulation results which show that the effects of hydrodynamic interactions are reduced as the distance between the confining plates is diminished. The main result of our study is that hydrodynamic interactions play a larger role in systems with a shorter Debye length, in contrast to conventional wisdom.

  20. Organisational learning via Interactive Process Simulation in AGE

    NARCIS (Netherlands)

    Szirbik, N. B.; Roest, G. B.; Sklenar, J; Tanguy, A; Bertelle, C; Fortino, G


    In this paper, the concept of Interactive Process Simulation is introduced as a specialisation of Business Gaming. A specific gaming and agent development framework, based oil interactive simulation and a specific modelling langauge, is shortly presented. The concepts of the language are explained

  1. Simulated galaxy interactions as probes of merger spectral energy distributions

    Energy Technology Data Exchange (ETDEWEB)

    Lanz, Lauranne; Zezas, Andreas; Smith, Howard A.; Ashby, Matthew L. N.; Fazio, Giovanni G.; Hernquist, Lars [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Hayward, Christopher C. [Heidelberger Institut für Theoretische Studien, Schloss-Wolfsbrunnenweg 35, D-69118 Heidelberg (Germany); Brassington, Nicola, E-mail: [School of Physics, Astronomy and Mathematics, University of Hertfordshire, College Lane, Hatfield, AL10 9AB (United Kingdom)


    We present the first systematic comparison of ultraviolet-millimeter spectral energy distributions (SEDs) of observed and simulated interacting galaxies. Our sample is drawn from the Spitzer Interacting Galaxy Survey and probes a range of galaxy interaction parameters. We use 31 galaxies in 14 systems which have been observed with Herschel, Spitzer, GALEX, and 2MASS. We create a suite of GADGET-3 hydrodynamic simulations of isolated and interacting galaxies with stellar masses comparable to those in our sample of interacting galaxies. Photometry for the simulated systems is then calculated with the SUNRISE radiative transfer code for comparison with the observed systems. For most of the observed systems, one or more of the simulated SEDs match reasonably well. The best matches recover the infrared luminosity and the star formation rate of the observed systems, and the more massive systems preferentially match SEDs from simulations of more massive galaxies. The most morphologically distorted systems in our sample are best matched to the simulated SEDs that are close to coalescence, while less evolved systems match well with the SEDs over a wide range of interaction stages, suggesting that an SED alone is insufficient for identifying the interaction stage except during the most active phases in strongly interacting systems. This result is supported by our finding that the SEDs calculated for simulated systems vary little over the interaction sequence.

  2. Ocelet: Simulating processes of landscape changes using interaction graphs

    Directory of Open Access Journals (Sweden)

    P. Degenne


    Full Text Available This paper introduces Ocelet, a domain specific language and simulation tool for modelling changes in geographical landscapes. It is characterised by the use of interaction graphs (graphs with interaction functions on their edges to represent the system as composed of processes, each involving several entities distributed in space that are in interaction with each other. Entities are the vertices of the graphs, and interactions are the edges on which (interaction functions can be applied to make the system change through time. Examples are given to illustrate the generic disposition of the simulation approach to model and study changing geographical setups.

  3. THIEF: An interactive simulation of nuclear materials safeguards

    Energy Technology Data Exchange (ETDEWEB)

    Stanbro, W. D.


    The safeguards community is facing an era in which it will be called upon to tighten protection of nuclear material. At the same time, it is probable that safeguards will face more competition for available resources from other activities such as environmental cleanup. To exist in this era, it will be necessary to understand and coordinate all aspects of the safeguards system. Because of the complexity of the interactions involved, this process puts a severe burden on designers and operators of safeguards systems. This paper presents a simulation tool developed at the Los Alamos National Laboratory to allow users to examine the interactions among safeguards elements as they apply to combating the insider threat. The tool consists of a microcomputer-based simulation in which the user takes the role of the insider trying to remove nuclear material from a facility. The safeguards system is run by the computer and consists of both physical protection and MC A computer elements. All data elements describing a scenario can be altered by the user. The program can aid in training, as well as in developing threat scenarios. 4 refs.

  4. Construction of Interaction Layer on Socio-Environmental Simulation (United States)

    Torii, Daisuke; Ishida, Toru

    In this study, we propose a method to construct a system based on a legacy socio-environmental simulator which enables to design more realistic interaction models in socio-environmetal simulations. First, to provide a computational model suitable for agent interactions, an interaction layer is constructed and connected from outside of a legacy socio-environmental simulator. Next, to configure the agents interacting ability, connection description for controlling the flow of information in the connection area is provided. As a concrete example, we realized an interaction layer by Q which is a scenario description language and connected it to CORMAS, a socio-envirionmental simulator. Finally, we discuss the capability of our method, using the system, in the Fire-Fighter domain.

  5. Cardiovascular drug trials: how to examine interaction, and why so

    NARCIS (Netherlands)

    Cleophas, T. J.; Zwinderman, A. H.; van Ouwerkerk, B.; Sobh, M.


    Background: In practice the benefit of cardiovascular medicines is less consistent than it is in clinical trials. This is due to multiple uncontrolled factors that co-determine the efficacy of the new treatment. In statistical terms, they interact with the new treatment. Interaction effects are

  6. Academic Examinations and Anxiety: The Interaction Model Empirically Tested. (United States)

    Phillips, J. Bryan; Endler, Norman S.


    Tested the person-by-situation interaction model of anxiety. Male (N=28) and female (N=79) university students served as subjects. Results were interpreted as providing support for the multidimensionality of A-Trait and further validation of the interaction model of anxiety. (Author)

  7. IMPETUS - Interactive MultiPhysics Environment for Unified Simulations. (United States)

    Ha, Vi Q; Lykotrafitis, George


    We introduce IMPETUS - Interactive MultiPhysics Environment for Unified Simulations, an object oriented, easy-to-use, high performance, C++ program for three-dimensional simulations of complex physical systems that can benefit a large variety of research areas, especially in cell mechanics. The program implements cross-communication between locally interacting particles and continuum models residing in the same physical space while a network facilitates long-range particle interactions. Message Passing Interface is used for inter-processor communication for all simulations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Preservice Special Education: Interactive Video Simulation. (United States)

    Evans, Robert J.

    The paper describes a microcomputer simulation program developed to train preservice special education teachers in the use of basic behavior modification skills. The program was written in SuperPILOT on an Apple IIe using a BCD interface card and a Panasonic NV 8200 video tape recorder. Production suggestions are offered. The incorporation of…

  9. Examining the Societal Impacts of Nanotechnology through Simulation: NANO SCENARIO (United States)

    Jarmon, Leslie; Keating, Elizabeth; Toprac, Paul


    This article describes a university-sponsored experiential-based simulation, the NANO SCENARIO, to increase the public's awareness and affect attitudes on the societal implications of nanoscience and nanotechnology by bringing together diverse stakeholders' perspectives in a participatory learning environment. Nanotechnology has the potential for…

  10. Dynamic Interactions for Network Visualization and Simulation (United States)


    Unmanned Aerial Vehicle . . . . . . . . . . . . . . . . . . 7 GUI Graphical User Interface . . . . . . . . . . . . . . . . . . . 8 MVC Model-View...applications, and web applets. Comprising a library of design algorithms, navigation and interaction techniques, prefuse aims to significantly sim- plify the...Information Visualization Reference Model of the Prefuse toolkit [15]. The prefuse toolkit is suitable for the Model-View-Controller ( MVC ) [15] soft- ware

  11. The Electron Transport Chain: An Interactive Simulation (United States)

    Romero, Chris; Choun, James


    This activity provides students an interactive demonstration of the electron transport chain and chemiosmosis during aerobic respiration. Students use simple, everyday objects as hydrogen ions and electrons and play the roles of the various proteins embedded in the inner mitochondrial membrane to show how this specific process in cellular…

  12. Interactive simulation of technology management foresight

    DEFF Research Database (Denmark)

    Hansen, Mette Sanne; Rasmussen, Lauge Baungaard; Jacobsen, Peter


    Two of the main foresight challenges are how to handle complexity and uncertainty of evolving technology tracks, which may merge and create new challenges for the management of a company in order to avoid sub- optimization. Complexity refers to the difficulty of identifying and quantifying causal...... about the use of a combined narrative and numerical simulation with the main purpose to provide more consistency between the strategic, tactical and operational plans and activities occurring in a company with special focus on technology management....

  13. Simulation of interactions at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Duckeck, Guenter [Munich Univ. (Germany). Physics Faculty


    The LHC Run-2 is planned to continue until end of 2018 and should increase the data volume by at least a factor 5 compared to Run-1. A corresponding increase of the simulated data volume is required in order to analyze and interpret the recorded data. This will allow us to determine with much better precision the properties of the Higgs Boson and either find new particles as predicted by 'New Physics' theories or further increase the constraints on these models. Using SuperMUC to simulate events will be a crucial component to reach these goals. Active development of the simulation software is ongoing in order to make the workflow more flexible and better parallelizable for smaller work-units. Adapting the software for Intel/Mic architectures is an important goal, though presumably more in the long-term after LHC Run-2 (Run-3 is planned to start in 2021). We would hope that ''SuperMUC Next Generation'' provides Intel/Mic architecture extensions.

  14. SOPHIA: Simulations Of Photo Hadronic Interactions in Astrophysics (United States)

    Reimer, A.; Engel, Ralph; Rachen, J. P.; Protheroe, R. J.; Stanev, Todor


    SOPHIA (Simulations Of Photo Hadronic Interactions in Astrophysics) solves problems connected to photohadronic processes in astrophysical environments and can also be used for radiation and background studies at high energy colliders such as LEP2 and HERA, as well as for simulations of photon induced air showers. SOPHIA implements well established phenomenological models, symmetries of hadronic interactions in a way that describes correctly the available exclusive and inclusive photohadronic cross section data obtained at fixed target and collider experiments.

  15. Evaluating Australian football league player contributions using interactive network simulation. (United States)

    Sargent, Jonathan; Bedford, Anthony


    This paper focuses on the contribution of Australian Football League (AFL) players to their team's on-field network by simulating player interactions within a chosen team list and estimating the net effect on final score margin. A Visual Basic computer program was written, firstly, to isolate the effective interactions between players from a particular team in all 2011 season matches and, secondly, to generate a symmetric interaction matrix for each match. Negative binomial distributions were fitted to each player pairing in the Geelong Football Club for the 2011 season, enabling an interactive match simulation model given the 22 chosen players. Dynamic player ratings were calculated from the simulated network using eigenvector centrality, a method that recognises and rewards interactions with more prominent players in the team network. The centrality ratings were recorded after every network simulation and then applied in final score margin predictions so that each player's match contribution-and, hence, an optimal team-could be estimated. The paper ultimately demonstrates that the presence of highly rated players, such as Geelong's Jimmy Bartel, provides the most utility within a simulated team network. It is anticipated that these findings will facilitate optimal AFL team selection and player substitutions, which are key areas of interest to coaches. Network simulations are also attractive for use within betting markets, specifically to provide information on the likelihood of a chosen AFL team list "covering the line ". Key pointsA simulated interaction matrix for Australian Rules football players is proposedThe simulations were carried out by fitting unique negative binomial distributions to each player pairing in a sideEigenvector centrality was calculated for each player in a simulated matrix, then for the teamThe team centrality measure adequately predicted the team's winning marginA player's net effect on margin could hence be estimated by replacing him in


    Directory of Open Access Journals (Sweden)

    Evžen Thöndel


    Full Text Available Interactive motion platforms are intended for vehicle simulators, where the direct interaction of the human body is used for controlling the simulated vehicle (e.g. bicycle, motorbike or other sports vehicles. The second use of interactive motion platforms is for entertainment purposes or fitness. The development of interactive motion platforms reacts to recent calls in the simulation industry to provide a device, which further enhances the virtual reality experience, especially with connection to the new and very fast growing business in virtual reality glasses. The paper looks at the design and control of an interactive motion platform with two degrees of freedom to be used in virtual reality applications. The paper provides the description of the control methods and new problems related to the virtual reality sickness are discussed here.

  17. Ken Jones [and] What Are We Talking About? [and] Simulations and Communication Skills in Secondary Schools [and] Simulations: Reading for Action [and] Who's Who, Who Sits Where [and] Simulations as Examinations [and] What Happens When Students Design and Run Their Own Simulations? [and] The Survival of the Blackest [and] Playing It for Real [and] Interactive Events: National Differences in Participation and Categorization [and] Beginnings and Other Starting Points [and] Three Categories of Ethics [and] Ken Jones's Books and Resources. (United States)

    van Ments, Morry; Brooks, Greg; Shirts, Garry; Jones, Ken


    Includes testimonials to, and previously published articles by, Ken Jones on categories in simulation; simulations in secondary schools, reading instruction, and English-as-a-Second-Language; simulations as assessment tools; aspects of design; differences in race, gender, and perceived ability and performance; influence of national culture;…

  18. The impact of social context on learning and cognitive demands for interactive virtual human simulations

    Directory of Open Access Journals (Sweden)

    Rebecca Lyons


    Full Text Available Interactive virtual human (IVH simulations offer a novel method for training skills involving person-to-person interactions. This article examines the effectiveness of an IVH simulation for teaching medical students to assess rare cranial nerve abnormalities in both individual and small-group learning contexts. Individual (n = 26 and small-group (n = 30 interaction with the IVH system was manipulated to examine the influence on learning, learner engagement, perceived cognitive demands of the learning task, and instructional efficiency. Results suggested the IVH activity was an equally effective and engaging instructional tool in both learning structures, despite learners in the group learning contexts having to share hands-on access to the simulation interface. Participants in both conditions demonstrated a significant increase in declarative knowledge post-training. Operation of the IVH simulation technology imposed moderate cognitive demand but did not exceed the demands of the task content or appear to impede learning.

  19. Interactive Simulations to Support Quantum Mechanics Instruction for Chemistry Students (United States)

    Kohnle, Antje; Benfield, Cory; Hahner, Georg; Paetkau, Mark


    The QuVis Quantum Mechanics Visualization Project provides freely available research-based interactive simulations with accompanying activities for the teaching and learning of quantum mechanics across a wide range of topics and levels. This article gives an overview of some of the simulations and describes their use in an introductory physical…

  20. Examining the Mechanical Equilibrium of Microscopic Stresses in Molecular Simulations (United States)

    Torres-Sánchez, Alejandro; Vanegas, Juan M.; Arroyo, Marino


    The microscopic stress field provides a unique connection between atomistic simulations and mechanics at the nanoscale. However, its definition remains ambiguous. Rather than a mere theoretical preoccupation, we show that this fact acutely manifests itself in local stress calculations of defective graphene, lipid bilayers, and fibrous proteins. We find that popular definitions of the microscopic stress violate the continuum statements of mechanical equilibrium, and we propose an unambiguous and physically sound definition.

  1. Mesoscale simulations of hydrodynamic squirmer interactions. (United States)

    Götze, Ingo O; Gompper, Gerhard


    The swimming behavior of self-propelled microorganisms is studied by particle-based mesoscale simulations. The simulation technique includes both hydrodynamics and thermal fluctuations that are both essential for the dynamics of microswimmers. The swimmers are modeled as squirmers, i.e., spherical objects with a prescribed tangential surface velocity, where the focus of thrust generation can be tuned from pushers to pullers. For passive squirmers (colloids), we show that the velocity autocorrelation function agrees quantitatively with the Boussinesq approximation. Single active squirmers show a persistent random-walk behavior, determined by forward motion, lateral diffusion, and orientational fluctuations, in agreement with theoretical predictions. For pairs of squirmers, which are initially swimming in parallel, we find an attraction for pushers and a repulsion for pullers, as expected. The hydrodynamic force between squirmer pairs is calculated as a function of the center-to-center distances d(cm) and is found to be consistent with a logarithmic distance dependence for d(cm) less than about two sphere diameters; here, the force is considerably stronger than expected from the far-field expansion. The dependence of the force strength on the asymmetry of the polar surface velocity is obtained. During the collision process, thermal fluctuations turn out to be very important and to strongly affect the postcollision velocity directions of both squirmers.

  2. Interfacial interaction between polypropylene and nanotube: A molecular dynamics simulation (United States)

    Zhang, Danhui; Yang, Houbo; Liu, Zhongkui; Liu, Anmin; Li, Yunfang


    The interfacial interaction between polypropylene (PE) and single walled carbon nanotube (SWCNT) was studied using molecular dynamics (MD) simulations. The result showed that the PE chain could stabilize the SWCNT and then extended along the direction of SWCNT. The mechanism of interfacial interaction between PE and SWCNT was also discussed. Furthermore, the interfacial interaction between more PE and SWCNT was also investigated and the position also deeply influenced the interaction. This will be beneficial to understanding the interfacial interaction between polymer and CNT in solution, and also guiding the fabrication of high performance polymer/CNT nanocomposites.


    Directory of Open Access Journals (Sweden)

    Jonathan Sargent


    Full Text Available This paper focuses on the contribution of Australian Football League (AFL players to their team's on-field network by simulating player interactions within a chosen team list and estimating the net effect on final score margin. A Visual Basic computer program was written, firstly, to isolate the effective interactions between players from a particular team in all 2011 season matches and, secondly, to generate a symmetric interaction matrix for each match. Negative binomial distributions were fitted to each player pairing in the Geelong Football Club for the 2011 season, enabling an interactive match simulation model given the 22 chosen players. Dynamic player ratings were calculated from the simulated network using eigenvector centrality, a method that recognises and rewards interactions with more prominent players in the team network. The centrality ratings were recorded after every network simulation and then applied in final score margin predictions so that each player's match contribution-and, hence, an optimal team-could be estimated. The paper ultimately demonstrates that the presence of highly rated players, such as Geelong's Jimmy Bartel, provides the most utility within a simulated team network. It is anticipated that these findings will facilitate optimal AFL team selection and player substitutions, which are key areas of interest to coaches. Network simulations are also attractive for use within betting markets, specifically to provide information on the likelihood of a chosen AFL team list "covering the line".

  4. Numerical simulation of wave interacting with a free rolling body

    Directory of Open Access Journals (Sweden)

    Jae Hwan Jung


    Full Text Available The present study numerically models the interaction between a regular wave and the roll motion of a rectangular floating structure. In order to simulate two-dimensional incompressible viscous two-phase flow in a numerical wave tank with the rectangular floating structure, the present study used the volume of fluid method based on the finite volume method. The sliding mesh technique is adopted to handle the motion of the rectangular floating structure induced by fluid-structure interaction. The effect of the wave period on the flow, roll motion and forces acting on the structure is examined by considering three different wave periods. The time variations of the wave height and the roll motion of the rectangular structure are in good agreement with experimental results for all wave periods. The present response amplitude operator is in good agreement with experimental results with the linear potential theory. The present numerical results effectively represent the entire process of vortex generation and evolution described by the experimental results. The longer wave period showed a different mechanism of the vortex evolution near each bottom corner of the structure compared to cases of shorter wave periods. In addition, the x-directional and z-directional forces acting on the structure are analyzed.

  5. Predicting Protein Interactions by Brownian Dynamics Simulations

    Directory of Open Access Journals (Sweden)

    Xuan-Yu Meng


    Full Text Available We present a newly adapted Brownian-Dynamics (BD-based protein docking method for predicting native protein complexes. The approach includes global BD conformational sampling, compact complex selection, and local energy minimization. In order to reduce the computational costs for energy evaluations, a shell-based grid force field was developed to represent the receptor protein and solvation effects. The performance of this BD protein docking approach has been evaluated on a test set of 24 crystal protein complexes. Reproduction of experimental structures in the test set indicates the adequate conformational sampling and accurate scoring of this BD protein docking approach. Furthermore, we have developed an approach to account for the flexibility of proteins, which has been successfully applied to reproduce the experimental complex structure from the structure of two unbounded proteins. These results indicate that this adapted BD protein docking approach can be useful for the prediction of protein-protein interactions.

  6. Simulating human behavior for national security human interactions.

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, Michael Lewis; Hart, Dereck H.; Verzi, Stephen J.; Glickman, Matthew R.; Wolfenbarger, Paul R.; Xavier, Patrick Gordon


    This 3-year research and development effort focused on what we believe is a significant technical gap in existing modeling and simulation capabilities: the representation of plausible human cognition and behaviors within a dynamic, simulated environment. Specifically, the intent of the ''Simulating Human Behavior for National Security Human Interactions'' project was to demonstrate initial simulated human modeling capability that realistically represents intra- and inter-group interaction behaviors between simulated humans and human-controlled avatars as they respond to their environment. Significant process was made towards simulating human behaviors through the development of a framework that produces realistic characteristics and movement. The simulated humans were created from models designed to be psychologically plausible by being based on robust psychological research and theory. Progress was also made towards enhancing Sandia National Laboratories existing cognitive models to support culturally plausible behaviors that are important in representing group interactions. These models were implemented in the modular, interoperable, and commercially supported Umbra{reg_sign} simulation framework.

  7. A Qualitative Examination of Social Interaction during Cooperative Computer Activities (United States)

    Hsu, I-Chen; Geist, Eugene A.


    This article reports the findings of a study to examine the practicality and efficacy of using tablet computers in the Higher Education classroom. Students in a senior level teacher preparation class were provided with Apple iPads for 10 weeks to aid in their studies. The iPads were preloaded with selected software but students were encouraged to…

  8. Building Interactive Simulations in Web Pages without Programming. (United States)

    Mailen Kootsey, J; McAuley, Grant; Bernal, Julie


    A software system is described for building interactive simulations and other numerical calculations in Web pages. The system is based on a new Java-based software architecture named NumberLinX (NLX) that isolates each function required to build the simulation so that a library of reusable objects could be assembled. The NLX objects are integrated into a commercial Web design program for coding-free page construction. The model description is entered through a wizard-like utility program that also functions as a model editor. The complete system permits very rapid construction of interactive simulations without coding. A wide range of applications are possible with the system beyond interactive calculations, including remote data collection and processing and collaboration over a network.

  9. Constructing International Relations Simulations: Examining the Pedagogy of IR Simulations through a Constructivist Learning Theory Lens (United States)

    Asal, Victor; Kratoville, Jayson


    Simulations are being used more and more in political science generally and in international relations specifically. While there is a growing body of literature describing different simulations and a small amount of literature that empirically tests the impact of simulations, scholars have written very little linking the pedagogic theory behind…

  10. Do Interracial Interactions Matter? An Examination of Student-Faculty Contact and Intellectual Self-Concept (United States)

    Cole, Darnell


    The purpose of this longitudinal, multi-institution study was to examine through multilevel analyses the influence of: (1) interracial interactions on student-faculty interactions; and (2) interracial interactions and student-faculty interactions on intellectual self-concept. Social participation and involvement theory, as they are constructed…

  11. Efficient simulation of strong system-environment interactions. (United States)

    Prior, Javier; Chin, Alex W; Huelga, Susana F; Plenio, Martin B


    Multicomponent quantum systems in strong interaction with their environment are receiving increasing attention due to their importance in a variety of contexts, ranging from solid state quantum information processing to the quantum dynamics of biomolecular aggregates. Unfortunately, these systems are difficult to simulate as the system-bath interactions cannot be treated perturbatively and standard approaches are invalid or inefficient. Here we combine the time-dependent density matrix renormalization group with techniques from the theory of orthogonal polynomials to provide an efficient method for simulating open quantum systems, including spin-boson models and their generalizations to multicomponent systems.

  12. Examining small molecule: HIV RNA interactions using arrayed imaging reflectometry (United States)

    Chaimayo, Wanaruk; Miller, Benjamin L.


    Human Immunodeficiency Virus (HIV) has been the subject of intense research for more than three decades as it causes an uncurable disease: Acquired Immunodeficiency Syndrome, AIDS. In the pursuit of a medical treatment, RNAtargeted small molecules are emerging as promising targets. In order to understand the binding kinetics of small molecules and HIV RNA, association (ka) and dissociation (kd) kinetic constants must be obtained, ideally for a large number of sequences to assess selectivity. We have developed Aqueous Array Imaged Reflectometry (Aq-AIR) to address this challenge. Using a simple light interference phenomenon, Aq-AIR provides real-time high-throughput multiplex capabilities to detect binding of targets to surface-immobilized probes in a label-free microarray format. The second generation of Aq-AIR consisting of high-sensitivity CCD camera and 12-μL flow cell was fabricated. The system performance was assessed by real-time detection of MBNL1-(CUG)10 and neomycin B - HIV RNA bindings. The results establish this second-generation Aq-AIR to be able to examine small molecules binding to RNA sequences specific to HIV.

  13. Human seat interaction simulation using RAMSIS and the dynamic simulation program MADYMO

    NARCIS (Netherlands)

    Happee, R.; Loczi, J.


    Both RAMSIS and MADYMO are widely applied for computer aided vehicle design. Both programs are used to simulate occupant-vehicle interactions where RAMSIS focuses on ergonomics in normal driving conditions and MADYMO focuses on passive safety in impact conditions. This paper describes simulations of

  14. Simulation of flame-vortex interaction using detailed and reduced

    Energy Technology Data Exchange (ETDEWEB)

    Hilka, M. [Gaz de France (GDF), 75 - Paris (France); Veynante, D. [Ecole Centrale de Paris, Laboratoire EM2C. CNRS, 92 - Chatenay-Malabry (France); Baum, M. [CERFACS (France); Poinsot, T.J. [Centre National de la Recherche Scientifique (CNRS), 45 - Orleans-la-Source (France). Institut de Mecanique des Fluides de Toulouse


    The interaction between a pair of counter-rotating vortices and a lean premixed CH{sub 4}/O{sub 2}/N{sub 2} flame ({Phi} = + 0.55) has been studied by direct numerical simulations using detailed and reduced chemical reaction schemes. Results from the complex chemistry simulation are discussed with respect to earlier experiments and differences in the simulations using detailed and reduces chemistry are investigated. Transient evolutions of the flame surface and the total heat release rate are compared and modifications in the evolution of the local flame structure are displayed. (authors) 22 refs.

  15. Teachers' Beliefs and Their Intention to Use Interactive Simulations in Their Classrooms (United States)

    Kriek, Jeanne; Stols, Gerrit


    In this pilot study, we sought to examine the influence of the beliefs of Grade 10 to 12 physical science teachers on their intended and actual usage of interactive simulations (Physics Education Technology, or PhET) in their classrooms. A combination of the Theory of Planned Behaviour, the Technology Acceptance Model and the Innovation Diffusion…

  16. Simulated disparity and peripheral blur interact during binocular fusion. (United States)

    Maiello, Guido; Chessa, Manuela; Solari, Fabio; Bex, Peter J


    We have developed a low-cost, practical gaze-contingent display in which natural images are presented to the observer with dioptric blur and stereoscopic disparity that are dependent on the three-dimensional structure of natural scenes. Our system simulates a distribution of retinal blur and depth similar to that experienced in real-world viewing conditions by emmetropic observers. We implemented the system using light-field photographs taken with a plenoptic camera which supports digital refocusing anywhere in the images. We coupled this capability with an eye-tracking system and stereoscopic rendering. With this display, we examine how the time course of binocular fusion depends on depth cues from blur and stereoscopic disparity in naturalistic images. Our results show that disparity and peripheral blur interact to modify eye-movement behavior and facilitate binocular fusion, and the greatest benefit was gained by observers who struggled most to achieve fusion. Even though plenoptic images do not replicate an individual’s aberrations, the results demonstrate that a naturalistic distribution of depth-dependent blur may improve 3-D virtual reality, and that interruptions of this pattern (e.g., with intraocular lenses) which flatten the distribution of retinal blur may adversely affect binocular fusion. © 2014 ARVO.

  17. Developing Models for Embodied Learning with Live Interactive Simulations

    DEFF Research Database (Denmark)

    Gjedde, Lisa


    Live simulations may offer a natural form of multimodal learning through embodied action, which can be engaging to a variety of learners and provide a platform for inclusion of special needs learners across the classroom. In this approach to interactive learning, the subject matter is embedded...

  18. Numerical Simulation of Wave Interaction with Moving Net Structures

    DEFF Research Database (Denmark)

    Chen, Hao; Christensen, Erik Damgaard


    was described as a sheet of porous media with prescribed rigid body motion and mesh motion was incorporated to conform the motion of the net. Free surface wave generation and absorption framework was also introduced to simulate wave interaction with moving net structures. The results showed that mesh motion...

  19. Effective Student Learning of Fractions with an Interactive Simulation (United States)

    Hensberry, Karina K. R.; Moore, Emily B.; Perkins, Katherine K.


    Computer technology, when coupled with reform-based teaching practices, has been shown to be an effective way to support student learning of mathematics. The quality of the technology itself, as well as how it is used, impacts how much students learn. Interactive simulations are dynamic virtual environments similar to virtual manipulatives that…

  20. I PASS: an interactive policy analysis simulation system. (United States)

    Doug Olson; Con Schallau; Wilbur Maki


    This paper describes an interactive policy analysis simulation system(IPASS) that can be used to analyze the long-term economic and demographic effects of alternative forest resource management policies. The IPASS model is a dynamic analytical tool that forecasts growth and development of an economy. It allows the user to introduce changes in selected parameters based...

  1. Modeling Collaborative Interaction Patterns in a Simulation-Based Task (United States)

    Andrews, Jessica J.; Kerr, Deirdre; Mislevy, Robert J.; von Davier, Alina; Hao, Jiangang; Liu, Lei


    Simulations and games offer interactive tasks that can elicit rich data, providing evidence of complex skills that are difficult to measure with more conventional items and tests. However, one notable challenge in using such technologies is making sense of the data generated in order to make claims about individuals or groups. This article…

  2. Two dimensional simulation of ion beam-plasm interaction | Echi ...

    African Journals Online (AJOL)

    Journal of the Nigerian Association of Mathematical Physics ... Abstract. Hybrid plasma simulation is a model in which different components of the plasma are treated differently. ... Deuterium ion beams incident on the tritium plasma interact with the plasma through the wake electric and magnetic fields of the beam currents.

  3. Real-time, interactive, visually updated simulator system for telepresence (United States)

    Schebor, Frederick S.; Turney, Jerry L.; Marzwell, Neville I.


    Time delays and limited sensory feedback of remote telerobotic systems tend to disorient teleoperators and dramatically decrease the operator's performance. To remove the effects of time delays, key components were designed and developed of a prototype forward simulation subsystem, the Global-Local Environment Telerobotic Simulator (GLETS) that buffers the operator from the remote task. GLETS totally immerses an operator in a real-time, interactive, simulated, visually updated artificial environment of the remote telerobotic site. Using GLETS, the operator will, in effect, enter into a telerobotic virtual reality and can easily form a gestalt of the virtual 'local site' that matches the operator's normal interactions with the remote site. In addition to use in space based telerobotics, GLETS, due to its extendable architecture, can also be used in other teleoperational environments such as toxic material handling, construction, and undersea exploration.

  4. Towards Real Time Simulation of Ship-Ship Interaction

    DEFF Research Database (Denmark)

    Lindberg, Ole; Bingham, Harry B.; Engsig-Karup, Allan Peter


    We present recent and preliminary work directed towards the development of a simplified, physics-based model for improved simulation of ship-ship interaction that can be used for both analysis and real-time computing (i.e. with real-time constraints due to visualization). The goal is to implement...... accurate (realistic) and much faster ship-wave and ship-ship simulations than are currently possible. The coupling of simulation with visualization should improve the visual experience such that it can be perceived as more realistic in training. Today the state-of-art in real-time ship-ship interaction...... is for efficiency reasons and time-constraints in visualization based on model experiments in towing tanks and precomputed force tables. We anticipate that the fast, and highly parallel, algorithm described by Engsig-Karup et al. [2011] for execution on affordable modern high-throughput Graphics Processing Units...

  5. Simulation training for breast and pelvic physical examination: a systematic review and meta-analysis. (United States)

    Dilaveri, C A; Szostek, J H; Wang, A T; Cook, D A


    Breast and pelvic examinations are challenging intimate examinations. Technology-based simulation may help to overcome these challenges. To synthesise the evidence regarding the effectiveness of technology-based simulation training for breast and pelvic examination. Our systematic search included MEDLINE, EMBASE, CINAHL, PsychINFO, Scopus, and key journals and review articles; the date of the last search was January 2012. Original research studies evaluating technology-enhanced simulation of breast and pelvic examination to teach learners, compared with no intervention or with other educational activities. The reviewers evaluated study eligibility and abstracted data on methodological quality, learners, instructional design, and outcomes, and used random-effects models to pool weighted effect sizes. In total, 11 272 articles were identified for screening, and 22 studies were eligible, enrolling 2036 trainees. In eight studies comparing simulation for breast examination training with no intervention, simulation was associated with a significant improvement in skill, with a pooled effect size of 0.86 (95% CI 0.52-1.19; P < 0.001). Four studies comparing simulation training for pelvic examination with no intervention had a large and significant benefit, with a pooled effect size of 1.18 (95% CI 0.40-1.96; P = 0.003). Among breast examination simulation studies, dynamic models providing feedback were associated with improved outcomes. In pelvic examination simulation studies, the addition of a standardised patient to the simulation model and the use of an electronic model with enhanced feedback improved outcomes. In comparison with no intervention, breast and pelvic examination simulation training is associated with moderate to large effects for skills outcomes. Enhanced feedback appears to improve learning. © 2013 RCOG.

  6. Optimization Model for Web Based Multimodal Interactive Simulations. (United States)

    Halic, Tansel; Ahn, Woojin; De, Suvranu


    This paper presents a technique for optimizing the performance of web based multimodal interactive simulations. For such applications where visual quality and the performance of simulations directly influence user experience, overloading of hardware resources may result in unsatisfactory reduction in the quality of the simulation and user satisfaction. However, optimization of simulation performance on individual hardware platforms is not practical. Hence, we present a mixed integer programming model to optimize the performance of graphical rendering and simulation performance while satisfying application specific constraints. Our approach includes three distinct phases: identification, optimization and update. In the identification phase, the computing and rendering capabilities of the client device are evaluated using an exploratory proxy code. This data is utilized in conjunction with user specified design requirements in the optimization phase to ensure best possible computational resource allocation. The optimum solution is used for rendering (e.g. texture size, canvas resolution) and simulation parameters (e.g. simulation domain) in the update phase. Test results are presented on multiple hardware platforms with diverse computing and graphics capabilities to demonstrate the effectiveness of our approach.

  7. Eulerian simulation of interacting PWR sprays: influence of droplet collisions

    Energy Technology Data Exchange (ETDEWEB)

    Foissac, A.; Malet, J. [Inst. de Radioprotection et de Surete Nucleaire, Saclay (France); Mimouni, S. [Electricite de France, Chatou (France); Ruyer, P. [Inst. de Radioprotection et de Surete Nucleaire, Saclay (France); Feuillebois, F. [Laboratoire d' Informatique pour la Mecanique et les Sciences de l' Ingenieur, Orsay (France); Simonin, O. [Inst. de Mecanique des Fluides de Toulouse, Toulouse (France)


    A numerical simulation of the interaction between two real Pressurized Water Reactor containment sprays is performed with a new model implemented into the Eulerian CFD code NEPTUNE{sub C}FD. The water droplet polydispersion in size has been treated with a sectional approach. The influence of collisions between droplets is taken into account with a statistical approach based on the various outcomes of binary collision. Experiments were performed on a new facility, and data obtained are compared with this two-fluid simulation. The results show a good agreement. (author)

  8. Uncertainty quantification in ion–solid interaction simulations

    Energy Technology Data Exchange (ETDEWEB)

    Preuss, R., E-mail:; Toussaint, U. von


    Within the framework of Bayesian uncertainty quantification we propose a non-intrusive reduced-order spectral approach (polynomial chaos expansion) to the simulation of ion–solid interactions. The method not only reduces the number of function evaluations but provides simultaneously a quantitative measure for which combinations of inputs have the most important impact on the result. It is applied to SDTRIM-simulations (Möller et al., 1988) with several uncertain and Gaussian distributed input parameters (i.e. angle, projectile energy, surface binding energy, target composition) and the results are compared to full-grid based approaches and sampling based methods with respect to reliability, efficiency and scalability.

  9. Testing advanced driver assistance systems with the interactive driving simulator; Erprobung von Fahrerassistenzsystemen mit dem Interactive Driving Simulator

    Energy Technology Data Exchange (ETDEWEB)

    Friedrichs, A.; Grosse-Kappenberg, S.; Happe, J. [Zentrum fuer Lern- und Wissensmanagement und Lehrstuhl Informatik im Maschinenbau ZLW/IMA der RWTH Aachen (Germany)


    The Centre for Learning and Knowledge Management and Department of Computer Science in Engineering of the Technical University Aachen has developed a truck driving simulator which combines a driving simulation as well as traffic flow calculations to the interactive Driving Simulator (InDriveS). In real-time the effects of the driver's behaviour on the surrounding traffic are considered and vice versa. The integrative part of InDriveS is a software-in-the-loop and hardware-in-the-loop development environment. By means of this tool, all phases of development (Analysis, Design, Modelling, Simulation, Implementation as well as Testing and Evaluation) of new vehicle technologies, e.g. Information and Assistance Systems, can be realised in consideration of the road traffic and the driver's behaviour. (orig.)

  10. Teachers' beliefs and their intention to use interactive simulations in ...

    African Journals Online (AJOL)

    A combination of the Theory of Planned Behaviour, the Technology Acceptance Model and the Innovation Diffusion Theory was used to examine the influence of teachers' attitudes, subjective norms and perceived behavioural control on their intention to use simulations in their classrooms. Using regression and factor ...

  11. Simulation of Fuzzy Adaptive PI Controlled Grid Interactive Inverter

    Directory of Open Access Journals (Sweden)

    Necmi ALTIN


    Full Text Available In this study, a voltage source grid interactive inverter is modeled and simulated in MATLAB/Simulink. Inverter is designed as current controlled and a fuzzy-PI current controller used for the generation of switching pattern to shape the inverter output current. The grid interactive inverter consists of a line frequency transformer and a LC type filter. Galvanic isolation between the grid and renewable energy source is obtained by the line frequency transformer and LC filter is employed to filter the high frequency harmonic components in current waveform due to PWM switching and to reduce the output current THD. Results of the MATLAB/Simulink simulation show that inverter output current is in sinusoidal waveform and in phase with line voltage, and current harmonics are in the limits of international standards (

  12. A treecode to simulate dust-plasma interactions

    CERN Document Server

    Thomas, D M


    The complex interaction of a small object with its surrounding plasma is an area of significant research with applications in a multitude of astrophysical, atmospheric, industrial and fusion plasmas. The computational study of these interactions has been dominated by macroscopic particle-in-cell (PIC) codes. This paper introduces a microscopic simulator of a spherical dust grain in a plasma, the plasma octree code pot, which uses the Barnes-Hut treecode algorithm to perform $N$-body simulations of electrons and ions in the vicinity of a spherical object. It also employs the Boris particle-motion integrator and Hutchinson's reinjection algorithm from SCEPTIC; a description of all three algorithms, and their implementation, is provided. Test results confirm the successful implementation of the treecode method and question the assumptions made by hybrid PIC codes.

  13. First-principles simulations of electrostatic interactions between dust grains

    CERN Document Server

    Itou, Hotaka; Hoshino, Masahiro


    We investigated the electrostatic interaction between two identical dust grains of an infinite mass immersed in homogeneous plasma by employing first-principles N-body simulations combined with the Ewald method. We specifically tested the possibility of an attractive force due to overlapping Debye spheres (ODSs), as was suggested by Resendes et al. (1998). Our simulation results demonstrate that the electrostatic interaction is repulsive and even stronger than the standard Yukawa potential. We showed that the measured electric field acting on the grain is highly consistent with a model electrostatic potential around a single isolated grain that takes into account a correction due to the orbital motion limited theory. Our result is qualitatively consistent with the counterargument suggested by Markes and Williams (2000), indicating the absence of the ODS attractive force.


    Directory of Open Access Journals (Sweden)

    Nina P. Dementievska


    Full Text Available Development of modern school physics experiment is related to the extensive use of ICT not only for data processing and visualization. Interactive computer simulation for processes and phenomena, developed by scientists and methodologists by the site Phet, helps to improve the physical demonstration experiment with the support of modern pedagogical technologies that change the traditional procedure to form students' understanding of the processes and phenomena, active cognitive activity. To study the influence of methods to integrate interactive computer simulations for better understanding the students' physical processes, phenomena and laws of the international community, teachers and Ukrainian scientists and teachers of physics have been involved. The aim of the article is to introduce the research results in the development and testing of individual components of educational technology in performing a physical experiment in secondary school.


    Directory of Open Access Journals (Sweden)

    P. Fiamma


    Full Text Available How to use for the architectural design, the simulation coming from a large size data model? The topic is related to the phase coming usually after the acquisition of the data, during the construction of the model and especially after, when designers must have an interaction with the simulation, in order to develop and verify their idea. In the case of study, the concept of interaction includes the concept of real time "flows". The work develops contents and results that can be part of the large debate about the current connection between "architecture" and "movement". The focus of the work, is to realize a collaborative and participative virtual environment on which different specialist actors, client and final users can share knowledge, targets and constraints to better gain the aimed result. The goal is to have used a dynamic micro simulation digital resource that allows all the actors to explore the model in powerful and realistic way and to have a new type of interaction in a complex architectural scenario. On the one hand, the work represents a base of knowledge that can be implemented more and more; on the other hand the work represents a dealt to understand the large constructed architecture simulation as a way of life, a way of being in time and space. The architectural design before, and the architectural fact after, both happen in a sort of "Spatial Analysis System". The way is open to offer to this "system", knowledge and theories, that can support architectural design work for every application and scale. We think that the presented work represents a dealt to understand the large constructed architecture simulation as a way of life, a way of being in time and space. Architecture like a spatial configuration, that can be reconfigurable too through designing.

  16. Neurosurgical simulation by interactive computer graphics on iPad. (United States)

    Maruyama, Keisuke; Kin, Taichi; Saito, Toki; Suematsu, Shinya; Gomyo, Miho; Noguchi, Akio; Nagane, Motoo; Shiokawa, Yoshiaki


    Presurgical simulation before complicated neurosurgery is a state-of-the-art technique, and its usefulness has recently become well known. However, simulation requires complex image processing, which hinders its widespread application. We explored handling the results of interactive computer graphics on the iPad tablet, which can easily be controlled anywhere. Data from preneurosurgical simulations from 12 patients (4 men, 8 women) who underwent complex brain surgery were loaded onto an iPad. First, DICOM data were loaded using Amira visualization software to create interactive computer graphics, and ParaView, another free visualization software package, was used to convert the results of the simulation to be loaded using the free iPad software KiwiViewer. The interactive computer graphics created prior to neurosurgery were successfully displayed and smoothly controlled on the iPad in all patients. The number of elements ranged from 3 to 13 (mean 7). The mean original data size was 233 MB, which was reduced to 10.4 MB (4.4% of original size) after image processing by ParaView. This was increased to 46.6 MB (19.9%) after decompression in KiwiViewer. Controlling the magnification, transfer, rotation, and selection of translucence in 10 levels of each element were smoothly and easily performed using one or two fingers. The requisite skill to smoothly control the iPad software was acquired within 1.8 trials on average in 12 medical students and 6 neurosurgical residents. Using an iPad to handle the result of preneurosurgical simulation was extremely useful because it could easily be handled anywhere.

  17. The use of visual interactive simulation techniques for production scheduling

    Directory of Open Access Journals (Sweden)

    W.H. Swan


    Full Text Available During the last decade visual interactive simulation has become established as a useful new tool for solving real life problems. It offers the Operational Research professional the opportunity to impact beneficially on important new decision making areas of business and industry. As an example, this paper discusses its application to the scheduling of production on batch chemical plants, which to date has remained largely a manual activity. Two different approaches are introduced, and it is concluded that while discrete event simulation is most useful as an aid to learning at a time of change, bar chart simulation is preferred for the day to day scheduling. The technique has been implemented on a number of plants and has led to significant improvements in their performance. Some areas for further development are identified.

  18. An Experimental Approach to Simulations of the CLIC Interaction Point

    DEFF Research Database (Denmark)

    Esberg, Jakob


    crystalline matter. The 6th chapter briefly introduces basic theoretical aspects that are natural for understanding the processes occurring at the interaction points of a future collider and in fixed target experiments. It is the purpose of this chapter to give basic formulas but also to give the reader...... experiments conducted at MAMI will be presented. Furthermore the chapter discusses the performance of new CMOS based detectors to be used in future experiments by the NA63 collaboration. The chapter on collider simulations introduces the beam-beam simulation codes GUINEA-PIG and GUINEA-PIG++, their methods...... of operation and their features. The characteristics of the simulated particles are presented and a comparison between the outputs of these codes with those from CAIN. \\item In the chapter on tridents, the implementation of the direct trident process in GUINEA-PIG++ is described. The results are compared...

  19. Simulation of intense short-pulse laser-plasma interaction

    Energy Technology Data Exchange (ETDEWEB)

    Yamagiwa, Mitsuru [Advanced Photon Research Center, Kansai Research Establishment, Japan Atomic Energy Research Inst., Kizu, Kyoto (Japan)


    We have completed the massive parallelization of a 2-dimensional giga-particle code and have achieved a 530-fold acceleration rate with 512 processing elements (PE's). Using this we have implemented a simulation of the interaction of a solid thin film and a high intensity laser and have discovered a phenomenon in which high quality short pulses from the far ultraviolet to soft X-rays are generated at the back surface of the thin layer. We have also introduced the atomic process database code (Hullac) and have the possibility for high precision simulations of X-ray laser radiation. With respect to laser acceleration we have the possibility to quantitatively evaluate relativistic self-focusing assumed to occur in higher intensity fields. Ion acceleration from a solid target and an underdense plasma irradiated by an intense and an ultra intense laser, respectively, has also been studied by particle-in-cell (PIC) simulations. (author)

  20. Interactive simulations as teaching tools for engineering mechanics courses (United States)

    Carbonell, Victoria; Romero, Carlos; Martínez, Elvira; Flórez, Mercedes


    This study aimed to gauge the effect of interactive simulations in class as an active teaching strategy for a mechanics course. Engineering analysis and design often use the properties of planar sections in calculations. In the stress analysis of a beam under bending and torsional loads, cross-sectional properties are used to determine stress and displacement distributions in the beam cross section. The centroid, moments and products of inertia of an area made up of several common shapes (rectangles usually) may thus be obtained by adding the moments of inertia of the component areas (U-shape, L-shape, C-shape, etc). This procedure is used to calculate the second moments of structural shapes in engineering practice because the determination of their moments of inertia is necessary for the design of structural components. This paper presents examples of interactive simulations developed for teaching the ‘Mechanics and mechanisms’ course at the Universidad Politecnica de Madrid, Spain. The simulations focus on fundamental topics such as centroids, the properties of the moment of inertia, second moments of inertia with respect to two axes, principal moments of inertia and Mohr's Circle for plane stress, and were composed using Geogebra software. These learning tools feature animations, graphics and interactivity and were designed to encourage student participation and engagement in active learning activities, to effectively explain and illustrate course topics, and to build student problem-solving skills.

  1. Teaching the rectal examination with simulations: effects on knowledge acquisition and inhibition. (United States)

    Siebeck, Matthias; Schwald, Bärbel; Frey, Claudia; Röding, Stefanie; Stegmann, Karsten; Fischer, Frank


    Undergraduate medical curricula are often deficient in teaching physical examinations in intimate zones, such as the rectal examination. Student inhibition is assumed to substantially hamper both the acquisition of knowledge and the performance of these examinations in practice. The two present studies examined the effects of low-fidelity (LFS) and high-fidelity (HFS) simulation on the acquisition of the necessary knowledge and inhibition about carrying out the rectal examination. In addition, we investigated the effects of the different sequencing of the two simulations (HFS-LFS versus LFS-HFS). A manikin for the rectal examination was used to implement the LFS. Standardised patients (SPs) were used to implement the HFS. Study samples consisted of 41 (Study 1) and 188 (Study 2) female and male undergraduate medical students. Each student participated in two individual sessions of 30 minutes each. Half the students participated first in the HFS and then in the LFS and the other half participated in the simulations in the opposite order. Outcome measures were self-rated inhibition and knowledge tests. In both studies, HFS was found to reduce inhibition significantly more than LFS. Furthermore, in Study 2, a marginal effect of the sequence of simulation was found. In both studies, both types of simulation were found to facilitate the acquisition of knowledge. There was no sequence effect for the acquisition of knowledge. Teaching the rectal examination with the help of SPs, who represent an HFS, can help medical undergraduate students to overcome inhibition about this examination. Standardised patient simulation is far more effective than that achieved using a manikin, which represents an LFS. Both types of simulation support the acquisition of knowledge. © Blackwell Publishing Ltd 2011.

  2. Blood vessel modeling for interactive simulation of interventional neuroradiology procedures. (United States)

    Kerrien, E; Yureidini, A; Dequidt, J; Duriez, C; Anxionnat, R; Cotin, S


    Endovascular interventions can benefit from interactive simulation in their training phase but also during pre-operative and intra-operative phases if simulation scenarios are based on patient data. A key feature in this context is the ability to extract, from patient images, models of blood vessels that impede neither the realism nor the performance of simulation. This paper addresses both the segmentation and reconstruction of the vasculature from 3D Rotational Angiography data, and adapted to simulation: An original tracking algorithm is proposed to segment the vessel tree while filtering points extracted at the vessel surface in the vicinity of each point on the centerline; then an automatic procedure is described to reconstruct each local unstructured point set as a skeleton-based implicit surface (blobby model). The output of successively applying both algorithms is a new model of vasculature as a tree of local implicit models. The segmentation algorithm is compared with Multiple Hypothesis Testing (MHT) algorithm (Friman et al., 2010) on patient data, showing its greater ability to track blood vessels. The reconstruction algorithm is evaluated on both synthetic and patient data and demonstrate its ability to fit points with a subvoxel precision. Various tests are also reported where our model is used to simulate catheter navigation in interventional neuroradiology. An excellent realism, and much lower computational costs are reported when compared to triangular mesh surface models. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Hands on + hands free: simulated on-call interaction. (United States)

    Fisher, James; Martin, Richard; Tate, David


    In hospital, doctors and nurses frequently discuss acutely unwell patients via the telephone. Telephone communication can be challenging, yet medical students receive little training in how to conduct such interactions. We aimed to provide a simple, innovative, simulation session to address this learning need for third-year medical students at Newcastle University. Groups of students were given a pager and a supervising tutor. Students responded to a 'bleep' from a nurse practitioner in a different room, who role-played a ward nurse concerned about a patient. Speakerphones were used, allowing the entire conversation to be audible. After the call, a student-led debriefing session took place. After the debriefing another student 'held' the bleep and a different scenario ensued. Following a resuscitation scenario, students made telephone contact with the medical registrar to hand over information pertaining to the case. Before and after the session, students rated their confidence in telephone interaction and handover using a 10-point Likert scale. Students also completed a feedback questionnaire. Fifty-four students attended the session. A statistically significant improvement in student confidence in telephone communication and handover was seen after the session. Free-text feedback highlighted that students had not received teaching on this previously, and that they welcomed opportunities to practise such skills within a controlled, safe environment. Simulation training can be costly, but speakerphones are cheap and readily available. Given the frequency of telephone interaction in hospital, we believe all medical students should receive telephone communication training. Locally, our department has now incorporated these teaching methods into simulation sessions elsewhere in the curriculum. Medical students receive little training in how to conduct [telephone] interactions. © 2014 John Wiley & Sons Ltd.

  4. Distributed interactive communication in simulated space-dwelling groups. (United States)

    Brady, Joseph V; Hienz, Robert D; Hursh, Steven R; Ragusa, Leonard C; Rouse, Charles O; Gasior, Eric D


    This report describes the development and preliminary application of an experimental test bed for modeling human behavior in the context of a computer generated environment to analyze the effects of variations in communication modalities, incentives and stressful conditions. In addition to detailing the methodological development of a simulated task environment that provides for electronic monitoring and recording of individual and group behavior, the initial substantive findings from an experimental analysis of distributed interactive communication in simulated space dwelling groups are described. Crews of three members each (male and female) participated in simulated "planetary missions" based upon a synthetic scenario task that required identification, collection, and analysis of geologic specimens with a range of grade values. The results of these preliminary studies showed clearly that cooperative and productive interactions were maintained between individually isolated and distributed individuals communicating and problem-solving effectively in a computer-generated "planetary" environment over extended time intervals without benefit of one another's physical presence. Studies on communication channel constraints confirmed the functional interchangeability between available modalities with the highest degree of interchangeability occurring between Audio and Text modes of communication. The effects of task-related incentives were determined by the conditions under which they were available with Positive Incentives effectively attenuating decrements in performance under stressful time pressure. c2003 Elsevier Ltd. All rights reserved.

  5. The Effectiveness of Public Simulated Oral Examinations in Preparation for the American Board of Surgery Certifying Examination: A Systematic Review. (United States)

    Pennell, Christopher; McCulloch, Peter


    The purpose of this study was to determine whether American Board of Surgery Certifying Examination (CE) performance is improved among residents who prepare using simulated oral examinations (SOEs). EMBASE and MEDLINE were searched using predefined search terms. No language restrictions were imposed and the latest search date was in November 2014. Included studies must have reported on residents training in a general surgery residency in the United States who used SOEs to prepare for the CE and have measured their performance against those without exposure to SOEs. Studies meeting inclusion criteria were qualitatively and quantitatively analyzed and a fixed effects meta-analysis was performed to determine the net effect of SOEs on CE performance. Overall, 4 of 25 abstracts reviewed met inclusion criteria and are included in this review. The most common simulation format included public examinations in front of resident peers during scheduled education sessions. All 4 included studies trended toward improved performance with SOEs and in 2 of these studies the improvement was statistically significant. Overall, 3 studies were of adequate quality to perform a meta-analysis and demonstrated a relative risk for first-attempt CE success of 1.22 (95% CI: 1.07-1.39, p = 0.003) for residents preparing with SOEs compared to those without SOEs. The published literature evaluating SOEs is limited and generally of fair quality. A modest improvement in CE performance was identified when public SOEs were used as an educational tool aimed to improve professionalism and communication skills, encourage reading at home, and provide a regular review of clinically relevant topics. Copyright © 2015 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

  6. Simulation of Propeller – Hull Interaction Using Ranse Solver

    Directory of Open Access Journals (Sweden)

    M.N. Senthil Prakash


    Full Text Available This work simulates propeller-hull interaction effects by a novel method namely, coupling a Vortex Lattice Method (VLM with a RANSE solver. The VLM generates the propeller forces based on the inputs of blade geometry, wake at propeller inlet, the required thrust and the propeller revolutions. The propeller forces thus obtained are distributed in the fluid domain at the propeller disk region at specific cells. These cells lie close to the blade coordinates and the forces are assigned to the centroids of cells by means of a user-defined function (UDF. The introduction of the body forces into the fluid domain, emulates the propeller action in the field of flow with consequent influences on the flow kinematics. Therefore the interaction effect between propeller and ship hull is simulated successfully by coupling the two methods. Thereby the kinematical aspects such as effective wake conditions are obtained. The results based on the methodology have been verified by comparison with data from the KCS ship available in recent published literature. The method establishes a successful numerical tank approach in understanding the ship hull-propeller interaction problem.

  7. A Graphical Interactive Simulation Environment for Production Planning in Bacon Factories

    DEFF Research Database (Denmark)

    Nielsen, Kirsten Mølgaard; Nielsen, Jens Frederik Dalsgaard


    The paper describes a graphical interactive simulation tool for production planning in bacon factories........The paper describes a graphical interactive simulation tool for production planning in bacon factories.....

  8. Simulation of single transparent molecule interaction with an optical microcavity

    Energy Technology Data Exchange (ETDEWEB)

    Quan Haiyong; Guo Zhixiong [Department of Mechanical and Aerospace Engineering, Rutgers, State University of New Jersey, Piscataway, NJ 08854 (United States)


    Finite-element simulations of nanoscale molecule interaction with the evanescent radiation field of an optical resonant microcavity are conducted to characterize the detection of single transparent molecules using the microcavity as an extremely sensitive micro/nano-sensor. The model sensor is an integrated device consisting of a dielectric microdisk and a waveguide that can be nanofabricated on Si-based dielectric thin film. When the microdisk is operated at a whispering-gallery mode, a strong evanescent field arises, surrounding the periphery of the cavity. Foreign target molecules such as proteins present in the near-field will interact with the electromagnetic resonant field and induce changes to the resonance. Such induced changes are investigated in this report and their significance in the detection of single molecules for nanotechnology development is discussed.

  9. Using Agent Based Modeling (ABM) to Develop Cultural Interaction Simulations (United States)

    Drucker, Nick; Jones, Phillip N.


    Today, most cultural training is based on or built around "cultural engagements" or discrete interactions between the individual learner and one or more cultural "others". Often, success in the engagement is the end or the objective. In reality, these interactions usually involve secondary and tertiary effects with potentially wide ranging consequences. The concern is that learning culture within a strict engagement context might lead to "checklist" cultural thinking that will not empower learners to understand the full consequence of their actions. We propose the use of agent based modeling (ABM) to collect, store, and, simulating the effects of social networks, promulgate engagement effects over time, distance, and consequence. The ABM development allows for rapid modification to re-create any number of population types, extending the applicability of the model to any requirement for social modeling.

  10. A limited assessment of the ASEP human reliability analysis procedure using simulator examination results

    Energy Technology Data Exchange (ETDEWEB)

    Gore, B.R.; Dukelow, J.S. Jr.; Mitts, T.M.; Nicholson, W.L. [Pacific Northwest Lab., Richland, WA (United States)


    This report presents a limited assessment of the conservatism of the Accident Sequence Evaluation Program (ASEP) human reliability analysis (HRA) procedure described in NUREG/CR-4772. In particular, the, ASEP post-accident, post-diagnosis, nominal HRA procedure is assessed within the context of an individual`s performance of critical tasks on the simulator portion of requalification examinations administered to nuclear power plant operators. An assessment of the degree to which operator perforn:Lance during simulator examinations is an accurate reflection of operator performance during actual accident conditions was outside the scope of work for this project; therefore, no direct inference can be made from this report about such performance. The data for this study are derived from simulator examination reports from the NRC requalification examination cycle. A total of 4071 critical tasks were identified, of which 45 had been failed. The ASEP procedure was used to estimate human error probability (HEP) values for critical tasks, and the HEP results were compared with the failure rates observed in the examinations. The ASEP procedure was applied by PNL operator license examiners who supplemented the limited information in the examination reports with expert judgment based upon their extensive simulator examination experience. ASEP analyses were performed for a sample of 162 critical tasks selected randomly from the 4071, and the results were used to characterize the entire population. ASEP analyses were also performed for all of the 45 failed critical tasks. Two tests were performed to assess the bias of the ASEP HEPs compared with the data from the requalification examinations. The first compared the average of the ASEP HEP values with the fraction of the population actually failed and it found a statistically significant factor of two bias on the average.


    Energy Technology Data Exchange (ETDEWEB)

    Christie, Duncan; Arras, Phil; Li, Zhi-Yun [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States)


    Gas giant exoplanets orbiting at close distances to the parent star are subjected to large radiation and stellar wind fluxes. In this paper, hydrodynamic simulations of the planetary upper atmosphere and its interaction with the stellar wind are carried out to understand the possible flow regimes and how they affect the Lyα transmission spectrum. Following Tremblin and Chiang, charge exchange reactions are included to explore the role of energetic atoms as compared to thermal particles. In order to understand the role of the tail as compared to the leading edge of the planetary gas, the simulations were carried out under axisymmetry, and photoionization and stellar wind electron impact ionization reactions were included to limit the extent of the neutrals away from the planet. By varying the planetary gas temperature, two regimes are found. At high temperature, a supersonic planetary wind is found, which is turned around by the stellar wind and forms a tail behind the planet. At lower temperatures, the planetary wind is shut off when the stellar wind penetrates inside where the sonic point would have been. In this regime mass is lost by viscous interaction at the boundary between planetary and stellar wind gases. Absorption by cold hydrogen atoms is large near the planetary surface, and decreases away from the planet as expected. The hot hydrogen absorption is in an annulus and typically dominated by the tail, at large impact parameter, rather than by the thin leading edge of the mixing layer near the substellar point.

  12. Numerical simulation of unsteady propeller/rudder interaction

    Directory of Open Access Journals (Sweden)

    Lei He


    Full Text Available A numerical approach based on a potential flow method is developed to simulate the unsteady interaction between propeller and rudder. In this approach, a panel method is used to solve the flow around the rudder and a vortex lattice method is used to solve the flow around the propeller, respectively. An iterative procedure is adopted to solve the interaction between propeller and rudder. The effects of one component on the other are evaluated by using induced velocities due to the other component at every time step. A fully unsteady wake alignment algorithm is implemented into the vortex lattice method to simulate the unsteady propeller flow. The Rosenhead-Moore core model is employed during the wake alignment procedure to avoid the singularities and instability. The Lamb-Oseen vortex model is adopted in the present method to decay the vortex strength around the rudder and to eliminate unrealistically high induced velocity. The present methods are applied to predict the performance of a cavitating horn-type rudder in the presence of a 6-bladed propeller. The predicted cavity patterns compare well with those observed from the experiments.

  13. Real time Monte Carlo simulation for evaluation of patient doses involved in radiological examinations

    Energy Technology Data Exchange (ETDEWEB)

    Fulea, D. [Institute of Public Health ' Prof.Dr.Iuliu Moldovan' , Cluj-Napoca (Romania); Cosma, C. [Babes-Bolyai Univ., Faculty of Physics, Cluj-Napoca (Romania)


    In order to apply the Monte Carlo simulation technique for usual radiological examinations we developed a Pc program, 'IradMed', written entirely in Java. The main purpose of this program is to compute the organ doses and the effective dose of patients, which are exposed at a X-ray beam having photon energies in 10 to 150 keV radiodiagnostic range. Three major radiological procedures are considered, namely mammography, radiography and CT. The fluoroscopy implies an irregular geometry and therefore it is neglected. Nevertheless, a gross estimation of patient doses can be made taking into account the fluoroscopy as being composed of several radiographic examinations applied in different anatomical regions. The interactions between radiation and matter are well-known, and the accuracy of the calculation is limited by the accuracy of the anatomical model used to describe actual patients and by characterisation of the radiation field applied. In this version of IradMed, it is assumed that the absorbed dose is equal with kerma for all tissues. No procedure has been used to take account of the finite range of the secondary electrons that are produced by photoelectric or Compton interactions. These ranges are small compared with the dimensions of the organs, and the absorbed dose will not change abruptly with distance except at boundary where composition and density change. However these boundary effects would have little effect in the determination of the average doses to almost all organs, except the active bone marrow which is treated separately. Another justification for this kerma approximation is the fact that the sum of all electron energies that exit the organ is statistically equal with the sum of all electron energies that enter in that particular organ. In this version of program, it is considered the following interactions: the Rayleigh scattering, the Compton scattering and the photoelectric effect. The Compton scattering is modeled by several

  14. Molecular dynamics simulation of gas models of Lennard-Jones type interactions: Extensivity associated with interaction range and external noise (United States)

    Kadijani, M. Nouri; Abbasi, H.; Nezamipour, S.


    Statistics of a two-dimensional gas model interacting through a Lennard-Jones type potential, is considered. The goal is to examine the extensivity of internal energy in respect to the potential range and external white noise through molecular dynamics simulation. Accordingly a molecular dynamics simulation model is designed that provides reasonable evidence, in this respect. It is shown that for the long range potential the internal energy scales according to non-extensive thermodynamics expectation and the criteria is specified. Besides, for the short range case we demonstrate that the external noise drastically modifies the statistics of gas and makes the internal energy non-extensive. The relation between the non-extensive parameter, q, and the relaxation time and the noise intensity is obtained.

  15. Functional interactivity in social media: an examination of Chinese health care organizations' microblog profiles. (United States)

    Jiang, Shaohai


    Social media hold enormous potentials as a communication tool for health care due to its interactive nature. However, prior research mainly focused on contingency interactivity of social media, by examining messages sent from health care organizations to audiences, while little is known about functional interactivity, which refers to social media's presence of functions for facilitating communication between users and its interface. That is, how health care organizations use interactive features on social media to communicate with the public. Thus, with a general basis of the functional interactivity framework proposed by Waters et al. (Engaging stakeholders through social networking: how nonprofit organizations are using Facebook. Pub Relat Rev 2009;35:102-106), the current study investigated three aspects of functional interactivity in microblogging, and its subsequent effects. Specifically, this study analyzed 500 Chinese hospitals' profiles on Sina Weibo, the most popular microblogging platform in China. The results showed that the most common functional interactivity feature was organization disclosure, followed by information dissemination, and audience involvement. These interactive features all positively predicted the number of followers. Also, Chinese private hospitals scored significantly higher than public hospitals to use interactive features offered by social media. The findings of this study provide important implications for health care organizations to understand new communicative functions available on social media, incorporate more functions into their profiles and thus provide audiences with greater opportunity to interact with them via social media. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email:

  16. Comparing models of star formation simulating observed interacting galaxies (United States)

    Quiroga, L. F.; Muñoz-Cuartas, J. C.; Rodrigues, I.


    In this work, we make a comparison between different models of star formation to reproduce observed interacting galaxies. We use observational data to model the evolution of a pair of galaxies undergoing a minor merger. Minor mergers represent situations weakly deviated from the equilibrium configuration but significant changes in star fomation (SF) efficiency can take place, then, minor mergers provide an unique scene to study SF in galaxies in a realistic but yet simple way. Reproducing observed systems also give us the opportunity to compare the results of the simulations with observations, which at the end can be used as probes to characterize the models of SF implemented in the comparison. In this work we compare two different star formation recipes implemented in Gadget3 and GIZMO codes. Both codes share the same numerical background, and differences arise mainly in the star formation recipe they use. We use observations from Pico dos Días and GEMINI telescopes and show how we use observational data of the interacting pair in AM2229-735 to characterize the interacting pair. Later we use this information to simulate the evolution of the system to finally reproduce the observations: Mass distribution, morphology and main features of the merger-induced star formation burst. We show that both methods manage to reproduce roughly the star formation activity. We show, through a careful study, that resolution plays a major role in the reproducibility of the system. In that sense, star formation recipe implemented in GIZMO code has shown a more robust performance. Acknowledgements: This work is supported by Colciencias, Doctorado Nacional - 617 program.

  17. Optimizing Noble Gas-Water Interactions via Monte Carlo Simulations. (United States)

    Warr, Oliver; Ballentine, Chris J; Mu, Junju; Masters, Andrew


    In this work we present optimized noble gas-water Lennard-Jones 6-12 pair potentials for each noble gas. Given the significantly different atomic nature of water and the noble gases, the standard Lorentz-Berthelot mixing rules produce inaccurate unlike molecular interactions between these two species. Consequently, we find simulated Henry's coefficients deviate significantly from their experimental counterparts for the investigated thermodynamic range (293-353 K at 1 and 10 atm), due to a poor unlike potential well term (εij). Where εij is too high or low, so too is the strength of the resultant noble gas-water interaction. This observed inadequacy in using the Lorentz-Berthelot mixing rules is countered in this work by scaling εij for helium, neon, argon, and krypton by factors of 0.91, 0.8, 1.1, and 1.05, respectively, to reach a much improved agreement with experimental Henry's coefficients. Due to the highly sensitive nature of the xenon εij term, coupled with the reasonable agreement of the initial values, no scaling factor is applied for this noble gas. These resulting optimized pair potentials also accurately predict partitioning within a CO2-H2O binary phase system as well as diffusion coefficients in ambient water. This further supports the quality of these interaction potentials. Consequently, they can now form a well-grounded basis for the future molecular modeling of multiphase geological systems.

  18. Simulating the interaction of seagrasses with their ambient flow (United States)

    Backhaus, Jan O.; Verduin, Jennifer J.


    The interaction of seagrasses with the dynamics of an oscillatory wave induced flow is assessed with a new Lagrangian plant model. The plant model simulates moving plants in canopies and their dissipative effect on the ambient flow. Concomitantly the plant model is interactively coupled to a 3D hydrodynamic numerical model allowing for a bilateral feedback between moving plants and flow. Model results demonstrate that this interaction causes a modification of current profiles within and above a canopy as compared to an undisturbed flow. While the overall effect of submerged plant canopies is a dampening of dynamics, the flow may locally be intensified. The model predicted an intensification of the flow near the top of a canopy in concurrence with field and laboratory observations. Dissipation in the coupled model, due to the applied non-linear friction law, grows exponentially with increasing flow. As a result the permeability of a canopy to the ambient flow decreases with increasing dissipation. Consequently, at high flow velocities, while becoming increasingly impermeable, a canopy acts like an obstacle that deflects the flow above it, which causes the observed intensification. Results for canopies consisting of seagrasses with different leaf structure and plant geometry show remarkable differences in predicted plant motions, current profiles, drag forces, and velocity shear. Predictions for moving plants are compared with those for rigid, less flexible, structures and undisturbed flow.

  19. Simulating the interaction of jets with the intracluster medium (United States)

    Weinberger, Rainer; Ehlert, Kristian; Pfrommer, Christoph; Pakmor, Rüdiger; Springel, Volker


    Jets from supermassive black holes in the centres of galaxy clusters are a potential candidate for moderating gas cooling and subsequent star formation through depositing energy in the intracluster gas. In this work, we simulate the jet-intracluster medium interaction using the moving-mesh magnetohydrodynamics code arepo. Our model injects supersonic, low-density, collimated and magnetized outflows in cluster centres, which are then stopped by the surrounding gas, thermalize and inflate low-density cavities filled with cosmic rays. We perform high-resolution, non-radiative simulations of the lobe creation, expansion and disruption, and find that its dynamical evolution is in qualitative agreement with simulations of idealized low-density cavities that are dominated by a large-scale Rayleigh-Taylor instability. The buoyant rising of the lobe does not create energetically significant small-scale chaotic motion in a volume-filling fashion, but rather a systematic upward motion in the wake of the lobe and a corresponding back-flow antiparallel to it. We find that, overall, 50 per cent of the injected energy ends up in material that is not part of the lobe, and about 25 per cent remains in the inner 100 kpc. We conclude that jet-inflated, buoyantly rising cavities drive systematic gas motions that play an important role in heating the central regions, while mixing of lobe material is subdominant. Encouragingly, the main mechanisms responsible for this energy deposition can be modelled already at resolutions within reach in future, high-resolution cosmological simulations of galaxy clusters.

  20. Numerical simulations of magnetic suspensions with hydrodynamic and dipole-dipole magnetic interactions (United States)

    Gontijo, R. G.; Cunha, F. R.


    volume fraction increased. This work is the first involving a magnetic suspension under the influence of both magnetic and hydrodynamic particle interactions. The mean sedimentation velocity and the suspension magnetization are examined under the steady-state condition over several realizations. Simulation results for the fluid magnetization are compared with a modified mean field theory, and a very good agreement for semi-dilute suspensions is observed. Additionally, the motion and shape transition of an initially spherical blob composed of magnetic spherical particles are investigated by computer simulations. We show the existence of velocity fluctuations due to the interplay of magnetically induced aggregates and their hydrodynamic dispersion. We find that the collective hydrodynamic interactions play a dispersive role opposite to the aggregative contribution of the magnetic dipole-dipole interactions.

  1. Web-based Interactive Landform Simulation Model - Grand Canyon (United States)

    Luo, W.; Pelletier, J. D.; Duffin, K.; Ormand, C. J.; Hung, W.; Iverson, E. A.; Shernoff, D.; Zhai, X.; Chowdary, A.


    Earth science educators need interactive tools to engage and enable students to better understand how Earth systems work over geologic time scales. The evolution of landforms is ripe for interactive, inquiry-based learning exercises because landforms exist all around us. The Web-based Interactive Landform Simulation Model - Grand Canyon (WILSIM-GC, is a continuation and upgrade of the simple cellular automata (CA) rule-based model (WILSIM-CA, that can be accessed from anywhere with an Internet connection. Major improvements in WILSIM-GC include adopting a physically based model and the latest Java technology. The physically based model is incorporated to illustrate the fluvial processes involved in land-sculpting pertaining to the development and evolution of one of the most famous landforms on Earth: the Grand Canyon. It is hoped that this focus on a famous and specific landscape will attract greater student interest and provide opportunities for students to learn not only how different processes interact to form the landform we observe today, but also how models and data are used together to enhance our understanding of the processes involved. The latest development in Java technology (such as Java OpenGL for access to ubiquitous fast graphics hardware, Trusted Applet for file input and output, and multithreaded ability to take advantage of modern multi-core CPUs) are incorporated into building WILSIM-GC and active, standards-aligned curricula materials guided by educational psychology theory on science learning will be developed to accompany the model. This project is funded NSF-TUES program.

  2. An examination of social interaction profiles based on the factors measured by the screen for social interaction. (United States)

    Mahoney, Emery B; Breitborde, Nicholas J K; Leone, Sarah L; Ghuman, Jaswinder Kaur


    Deficits in the capacity to engage in social interactions are a core deficit associated with Autistic Disorder (AD) and Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS). These deficits emerge at a young age, making screening for social interaction deficits and interventions targeted at improving capacity in this area important for early identification and intervention. Screening and early intervention efforts are particularly important given the poor short and long term outcomes for children with Autism Spectrum Disorders (ASDs) who experience social interaction deficits. The Screen for Social Interaction (SSI) is a well-validated screening measure that examines a child's capacity for social interaction using a developmental approach. The present study identified four underlying factors measured by the SSI, namely, Connection with Caregiver, Interaction/Imagination, Social Approach/Interest, and Agreeable Nature. The resulting factors were utilized to compare social interaction profiles across groups of children with AD, PDD-NOS, children with non-ASD developmental and/or psychiatric conditions and typically developing children. The results indicate that children with AD and those with PDD-NOS had similar social interaction profiles, but were able to be distinguished from typically developing children on every factor and were able to be distinguished from children with non-ASD psychiatric conditions on every factor except the Connection with Caregiver factor. In addition, children with non-ASD developmental and/or psychiatric conditions could be distinguished from typically developing children on the Connection with Caregiver factor and the Social Approach/Interest factor. These findings have implications for screening and intervention for children with ASDs and non-ASD psychiatric conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Simulating electric field interactions with polar molecules using spectroscopic databases. (United States)

    Owens, Alec; Zak, Emil J; Chubb, Katy L; Yurchenko, Sergei N; Tennyson, Jonathan; Yachmenev, Andrey


    Ro-vibrational Stark-associated phenomena of small polyatomic molecules are modelled using extensive spectroscopic data generated as part of the ExoMol project. The external field Hamiltonian is built from the computed ro-vibrational line list of the molecule in question. The Hamiltonian we propose is general and suitable for any polar molecule in the presence of an electric field. By exploiting precomputed data, the often prohibitively expensive computations associated with high accuracy simulations of molecule-field interactions are avoided. Applications to strong terahertz field-induced ro-vibrational dynamics of PH 3 and NH 3 , and spontaneous emission data for optoelectrical Sisyphus cooling of H 2 CO and CH 3 Cl are discussed.

  4. Beam equipment electromagnetic interaction in accelerators: simulation and experimental benchmarking

    CERN Document Server

    Passarelli, Andrea; Vaccaro, Vittorio Giorgio; Massa, Rita; Masullo, Maria Rosaria

    One of the most significant technological problems to achieve the nominal performances in the Large Hadron Collider (LHC) concerns the system of collimation of particle beams. The use of collimators crystals, exploiting the channeling effect on extracted beam, has been experimentally demonstrated. The first part of this thesis is about the optimization of UA9 goniometer at CERN, this device used for beam collimation will replace a part of the vacuum chamber. The optimization process, however, requires the calculation of the coupling impedance between the circulating beam and this structure in order to define the threshold of admissible intensity to do not trigger instability processes. Simulations have been performed with electromagnetic codes to evaluate the coupling impedance and to assess the beam-structure interaction. The results clearly showed that the most concerned resonance frequencies are due solely to the open cavity to the compartment of the motors and position sensors considering the crystal in o...

  5. Working with simulated forms of interaction in health care education

    DEFF Research Database (Denmark)

    Olesen, Birgitte Ravn; Nordentoft, Helle Merete

    in which role-play of practice situations - both live and performed on video - formed the launching-pad for participants’ oral and written reflections. Our findings show that role-play has the potential to 1) develop professionals’ sensitivity to the significance of unexpected, embodied and emotional......This paper argues that role-play as a simulated form of interaction - live and performed on video - is a creative method which has the potential to generate and support authentic dialogues in practice. In the paper we draw on experiences from 6 interdisciplinary workshops at a Danish hospital...... aspects of health care practices and 2) to display tensions between participants’ different perspectives on the same situation. We conclude that the dialogical process of raising reflexive awareness of tensions makes role-play a powerful creative method in health care education....

  6. Reduced model (SOLT) simulations of neutral-plasma interaction (United States)

    Russell, David; Myra, James


    The 2D scrape-off-layer turbulence (SOLT) code has been enhanced by the addition of kinetic-neutral physics. Plasma-neutral interactions include charge exchange (CX) and ionization (IZ). Under the assumption that the CX and IZ collision rates are independent of the ion-neutral relative velocity, a 1D (radial: x) Boltzmann equation has been derived for the evolution of the (vy,vz) -averaged neutral distribution function (G), and that evolution has been added to SOLT. The CX and IZ rates are determined by the poloidally (y) averaged plasma density and temperatures, and G = G(x,vx,t). Results from 1D simulations that use diffusion as a proxy for turbulent transport are presented to illustrate the capability, including the approach to a steady state driven by sustained neutral injection in the far-SOL and source-driven heating in the core. Neutral density and energy profiles are obtained for the resulting self-consistent equilibrium plasma profiles. The effect of neutral drag on poloidal ExB mean flow and shearing rate is illustrated. Progress on 2D turbulence (blob) simulations is reported. Work supported by the U.S. Department of Energy Office of Science, Office of Fusion Energy Sciences, under Award Number DE-FG02-97ER54392.

  7. Enhancing food engineering education with interactive web-based simulations

    Directory of Open Access Journals (Sweden)

    Alexandros Koulouris


    Full Text Available In the traditional deductive approach in teaching any engineering topic, teachers would first expose students to the derivation of the equations that govern the behavior of a physical system and then demonstrate the use of equations through a limited number of textbook examples. This methodology, however, is rarely adequate to unmask the cause-effect and quantitative relationships between the system variables that the equations embody. Web-based simulation, which is the integration of simulation and internet technologies, has the potential to enhance the learning experience by offering an interactive and easily accessible platform for quick and effortless experimentation with physical phenomena.This paper presents the design and development of a web-based platform for teaching basic food engineering phenomena to food technology students. The platform contains a variety of modules (“virtual experiments” covering the topics of mass and energy balances, fluid mechanics and heat transfer. In this paper, the design and development of three modules for mass balances and heat transfer is presented. Each webpage representing an educational module has the following features: visualization of the studied phenomenon through graphs, charts or videos, computation through a mathematical model and experimentation.  The student is allowed to edit key parameters of the phenomenon and observe the effect of these changes on the outputs. Experimentation can be done in a free or guided fashion with a set of prefabricated examples that students can run and self-test their knowledge by answering multiple-choice questions.

  8. Assessment of robotic patient simulators for training in manual physical therapy examination techniques. (United States)

    Ishikawa, Shun; Okamoto, Shogo; Isogai, Kaoru; Akiyama, Yasuhiro; Yanagihara, Naomi; Yamada, Yoji


    Robots that simulate patients suffering from joint resistance caused by biomechanical and neural impairments are used to aid the training of physical therapists in manual examination techniques. However, there are few methods for assessing such robots. This article proposes two types of assessment measures based on typical judgments of clinicians. One of the measures involves the evaluation of how well the simulator presents different severities of a specified disease. Experienced clinicians were requested to rate the simulated symptoms in terms of severity, and the consistency of their ratings was used as a performance measure. The other measure involves the evaluation of how well the simulator presents different types of symptoms. In this case, the clinicians were requested to classify the simulated resistances in terms of symptom type, and the average ratios of their answers were used as performance measures. For both types of assessment measures, a higher index implied higher agreement among the experienced clinicians that subjectively assessed the symptoms based on typical symptom features. We applied these two assessment methods to a patient knee robot and achieved positive appraisals. The assessment measures have potential for use in comparing several patient simulators for training physical therapists, rather than as absolute indices for developing a standard.

  9. Case Study: An Examination of the Decision Making Process for Selecting Simulations for an Online MBA Program (United States)

    Neely, Pat; Tucker, Jan


    Purpose: Simulations are designed as activities which imitate real world scenarios and are often used to teach and enhance skill building. The purpose of this case study is to examine the decision making process and outcomes of a faculty committee tasked with examining simulations in the marketplace to determine if the simulations could be used as…

  10. Order Effects of Learning with Modeling and Simulation Software on Field-Dependent and Field-Independent Children's Cognitive Performance: An Interaction Effect (United States)

    Angeli, Charoula; Valanides, Nicos; Polemitou, Eirini; Fraggoulidou, Elena


    The study examined the interaction between field dependence-independence (FD/I) and learning with modeling software and simulations, and their effect on children's performance. Participants were randomly assigned into two groups. Group A first learned with a modeling tool and then with simulations. Group B learned first with simulations and then…

  11. Interactive Whiteboards in Mathematics Spaces: An Examination of Technology Integration in An Urban Middle School (United States)

    Young, Jamaal; Hamilton, Christina; Cason, Marti


    The purpose of this study was to examine the effects of integrating Interactive Whiteboard (IWB) technology on middle school mathematics achievement in an urban school. Propensity score matching was used to create a comparable control group in order to isolate the effects of IWB technology on mathematics achievement. An initial experimental group…

  12. Parental Anxiety and Child Symptomatology: An Examination of Additive and Interactive Effects of Parent Psychopathology (United States)

    Burstein, Marcy; Ginsburg, Golda S.; Tein, Jenn-Yun


    The current study examined relations between parent anxiety and child anxiety, depression, and externalizing symptoms. In addition, the study tested the additive and interactive effects of parent anxiety with parent depression and externalizing symptoms in relation to child symptoms. Forty-eight parents with anxiety disorders and 49 parents…

  13. Social Interaction, Age, and Ethnicity: An Examination of the "Double Jeopardy" Hypothesis. (United States)

    Dowd, James J.; Bengston, Vern L.

    This paper explores the relationships among ethnicity, age and inherent social dilemmas. The study examines selected dependent variables (economic and health indicators, social interaction, and life satisfaction items) in an effort to determine the extent to which different configurations of age, ethnicity and socioeconomic status produce varying…

  14. Examining Gender Differences in Attitudes toward Interactive Classroom Communications Systems (ICCS) (United States)

    Kay, Robin H.


    An interactive classroom communication system (ICCS) involves the use of remote devices that permit all students in a class to respond to multiple choice questions displayed on a LCD projector. After responses are clicked in, the results are instantly aggregated and displayed in chart form. The purpose of this study was to examine gender…

  15. A critical examination of the maximum velocity of shortening used in simulation models of human movement. (United States)

    Domire, Zachary J; Challis, John H


    The maximum velocity of shortening of a muscle is an important parameter in musculoskeletal models. The most commonly used values are derived from animal studies; however, these values are well above the values that have been reported for human muscle. The purpose of this study was to examine the sensitivity of simulations of maximum vertical jumping performance to the parameters describing the force-velocity properties of muscle. Simulations performed with parameters derived from animal studies were similar to measured jump heights from previous experimental studies. While simulations performed with parameters derived from human muscle were much lower than previously measured jump heights. If current measurements of maximum shortening velocity in human muscle are correct, a compensating error must exist. Of the possible compensating errors that could produce this discrepancy, it was concluded that reduced muscle fibre excursion is the most likely candidate.

  16. Examining pediatric resuscitation education using simulation and scripted debriefing: a multicenter randomized trial. (United States)

    Cheng, Adam; Hunt, Elizabeth A; Donoghue, Aaron; Nelson-McMillan, Kristen; Nishisaki, Akira; Leflore, Judy; Eppich, Walter; Moyer, Mike; Brett-Fleegler, Marisa; Kleinman, Monica; Anderson, Jodee; Adler, Mark; Braga, Matthew; Kost, Susanne; Stryjewski, Glenn; Min, Steve; Podraza, John; Lopreiato, Joseph; Hamilton, Melinda Fiedor; Stone, Kimberly; Reid, Jennifer; Hopkins, Jeffrey; Manos, Jennifer; Duff, Jonathan; Richard, Matthew; Nadkarni, Vinay M


    Resuscitation training programs use simulation and debriefing as an educational modality with limited standardization of debriefing format and content. Our study attempted to address this issue by using a debriefing script to standardize debriefings. To determine whether use of a scripted debriefing by novice instructors and/or simulator physical realism affects knowledge and performance in simulated cardiopulmonary arrests. DESIGN Prospective, randomized, factorial study design. The study was conducted from 2008 to 2011 at 14 Examining Pediatric Resuscitation Education Using Simulation and Scripted Debriefing (EXPRESS) network simulation programs. Interprofessional health care teams participated in 2 simulated cardiopulmonary arrests, before and after debriefing. We randomized 97 participants (23 teams) to nonscripted low-realism; 93 participants (22 teams) to scripted low-realism; 103 participants (23 teams) to nonscripted high-realism; and 94 participants (22 teams) to scripted high-realism groups. INTERVENTION Participants were randomized to 1 of 4 arms: permutations of scripted vs nonscripted debriefing and high-realism vs low-realism simulators. Percentage difference (0%-100%) in multiple choice question (MCQ) test (individual scores), Behavioral Assessment Tool (BAT) (team leader performance), and the Clinical Performance Tool (CPT) (team performance) scores postintervention vs preintervention comparison (PPC). There was no significant difference at baseline in nonscripted vs scripted groups for MCQ (P = .87), BAT (P = .99), and CPT (P = .95) scores. Scripted debriefing showed greater improvement in knowledge (mean [95% CI] MCQ-PPC, 5.3% [4.1%-6.5%] vs 3.6% [2.3%-4.7%]; P = .04) and team leader behavioral performance (median [interquartile range (IQR)] BAT-PPC, 16% [7.4%-28.5%] vs 8% [0.2%-31.6%]; P = .03). Their improvement in clinical performance during simulated cardiopulmonary arrests was not significantly different (median [IQR] CPT-PPC, 7.9% [4

  17. Modeling and simulation of protein-surface interactions: achievements and challenges. (United States)

    Ozboyaci, Musa; Kokh, Daria B; Corni, Stefano; Wade, Rebecca C


    Understanding protein-inorganic surface interactions is central to the rational design of new tools in biomaterial sciences, nanobiotechnology and nanomedicine. Although a significant amount of experimental research on protein adsorption onto solid substrates has been reported, many aspects of the recognition and interaction mechanisms of biomolecules and inorganic surfaces are still unclear. Theoretical modeling and simulations provide complementary approaches for experimental studies, and they have been applied for exploring protein-surface binding mechanisms, the determinants of binding specificity towards different surfaces, as well as the thermodynamics and kinetics of adsorption. Although the general computational approaches employed to study the dynamics of proteins and materials are similar, the models and force-fields (FFs) used for describing the physical properties and interactions of material surfaces and biological molecules differ. In particular, FF and water models designed for use in biomolecular simulations are often not directly transferable to surface simulations and vice versa. The adsorption events span a wide range of time- and length-scales that vary from nanoseconds to days, and from nanometers to micrometers, respectively, rendering the use of multi-scale approaches unavoidable. Further, changes in the atomic structure of material surfaces that can lead to surface reconstruction, and in the structure of proteins that can result in complete denaturation of the adsorbed molecules, can create many intermediate structural and energetic states that complicate sampling. In this review, we address the challenges posed to theoretical and computational methods in achieving accurate descriptions of the physical, chemical and mechanical properties of protein-surface systems. In this context, we discuss the applicability of different modeling and simulation techniques ranging from quantum mechanics through all-atom molecular mechanics to coarse

  18. Hybrid Simulations of the Interaction Between Solar Wind Flow and the Hermean Magnetosphere (United States)

    Travnicek, P.; Hellinger, P.; Schriver, D.; Ashour-Abdalla, M.


    We examine the magnetosphere of Mercury using global three dimensional hybrid plasma simulations. Hybrid simulations treat ions as particles and electrons as a fluid. Having ions as particles allows ion kinetic behavior and waves to be included in the physical treatment of the plasma as compared to magnetohydrodynamic (MHD) modeling that treats the plasma as a single magnetized fluid and does not include such kinetic effects. Kinetic effects are essential for understanding magnetospheric physics. Hybrid simulations scale to the ion inertial length and thus on a global scale are somewhat limited in spatial extent compared to an MHD simulation. We note effects caused by the scalling of the numerical model of the magnetized obstacle interacting with the solar wind flow with the full scale simulation. Hermean magnetosphere is estimated to be only a few times the planetary radius, it can fit within a hybrid simulation system. The overal structure of the interaction between a magnetized obstacle in the solar wind flow is determined by few basic parameters (namely the solar wind density, background magnetic field, and the speed of solar wind, and also the strength of the magnetic dipole of the obstacle and its radius). The structure of the interaction of the solar wind flow with Mercury is to a large extend unique when compared to other planets. For example, the magnetic moment of the Mercury is over 1000 times smaller than that of the Earth and also the solar wind is stronger nearby Mercury than at Earth's vicinity. The typical magnetosperic scales are comparable to the ion gyroradii and hence kinetic effects are important for the overall structure of the interaction between the Hermean magnetospere and the solar wind. In this paper we shall focus on the study of the overal structure of the bow shock and magnetosheath of Mercury. We shall examine the formation of the magnetospheric tail. We shall study particle distribution functions in different locations of the

  19. Cloud Service for Interactive Simulation of Interregional Trade

    Directory of Open Access Journals (Sweden)

    A. S. Velichko


    Full Text Available The paper describes a mathematical model of trade flows between the territories of a region or a country in a transport network having one or more different types of marine or ground transportation. We use the approach of modeling complex communication systems to determine the most probable values of flows in case of incomplete information about the system. Transport costs between the territories are modeled within the framework of the gravity model. The payment for transportation depends on the distance between regions, the distance is estimated as the shortest way length in a given transport network or geographical distance. The mathematical formulation of the problem belongs to the class of convex mathematical programming problems and assumes the numerical solution of nonlinear optimization problem with linear constraints. Based on the model, the software is implemented as a cloud service on heterogeneous computing architectures: the simulation module is made on a highperformance server platform, management and visualization modules are produced with IACPaaS cloud platform. Communication between the platforms is established via asynchronous http-queries. For information exchange between the modules the declarative model with JSON format is developed and implemented for the objects considered in the mathematical model which are products, areas and communications. Visualization module allows to present graphically the original and the resulting matrix data and to modify the input parameters of the model interactively. The paper demonstrates the use of software for the simulation of inter-regional freight traffic of the Russian Far East region based on input data provided by open statistics sources.

  20. A THC Simulator for Modeling Fluid-Rock Interactions (United States)

    Hamidi, Sahar; Galvan, Boris; Heinze, Thomas; Miller, Stephen


    Fluid-rock interactions play an essential role in many earth processes, from a likely influence on earthquake nucleation and aftershocks, to enhanced geothermal system, carbon capture and storage (CCS), and underground nuclear waste repositories. In THC models, two-way interactions between different processes (thermal, hydraulic and chemical) are present. Fluid flow influences the permeability of the rock especially if chemical reactions are taken into account. On one hand solute concentration influences fluid properties while, on the other hand, heat can affect further chemical reactions. Estimating heat production from a naturally fractured geothermal systems remains a complex problem. Previous works are typically based on a local thermal equilibrium assumption and rarely consider the salinity. The dissolved salt in fluid affects the hydro- and thermodynamical behavior of the system by changing the hydraulic properties of the circulating fluid. Coupled thermal-hydraulic-chemical models (THC) are important for investigating these processes, but what is needed is a coupling to mechanics to result in THMC models. Although similar models currently exist (e.g. PFLOTRAN), our objective here is to develop algorithms for implementation using the Graphics Processing Unit (GPU) computer architecture to be run on GPU clusters. To that aim, we present a two-dimensional numerical simulation of a fully coupled non-isothermal non-reactive solute flow. The thermal part of the simulation models heat transfer processes for either local thermal equilibrium or nonequilibrium cases, and coupled to a non-reactive mass transfer described by a non-linear diffusion/dispersion model. The flow process of the model includes a non-linear Darcian flow for either saturated or unsaturated scenarios. For the unsaturated case, we use the Richards' approximation for a mixture of liquid and gas phases. Relative permeability and capillary pressure are determined by the van Genuchten relations

  1. Unsupportive social interactions and affective states: examining associations of two oxytocin-related polymorphisms. (United States)

    McInnis, Opal A; McQuaid, Robyn J; Matheson, Kimberly; Anisman, Hymie


    Two single-nucleotide polymorphisms (SNPs) on oxytocin-related genes, specifically the oxytocin receptor (OXTR) rs53576 and the CD38 rs3796863 variants, have been associated with alterations in prosocial behaviors. A cross-sectional study was conducted among undergraduate students (N = 476) to examine associations between the OXTR and CD38 polymorphisms and unsupportive social interactions and mood states. Results revealed no association between perceived levels of unsupportive social interactions and the OXTR polymorphism. However, A carriers of the CD38 polymorphism, a variant previously associated with elevated oxytocin, reported greater perceived peer unsupportive interactions compared to CC carriers. As expected, perceived unsupportive interactions from peers was associated with greater negative affect, which was moderated by the CD38 polymorphism. Specifically, this relation was stronger among CC carriers of the CD38 polymorphism (a variant thought to be linked to lower oxytocin). When examining whether the OXTR polymorphism moderated the relation between unsupportive social interactions from peers and negative affect there was a trend toward significance, however, this did not withstand multiple testing corrections. These findings are consistent with the perspective that a variant on an oxytocin polymorphism that may be tied to lower oxytocin is related to poor mood outcomes in association with negative social interactions. At the same time, having a genetic constitution presumed to be associated with higher oxytocin was related to increased perceptions of unsupportive social interactions. These seemingly paradoxical findings could be related to previous reports in which variants associated with prosocial behaviors were also tied to relatively more effective coping styles to deal with challenges.

  2. Teachers' beliefs and their intention to use interactive simulations in their classrooms

    Directory of Open Access Journals (Sweden)

    Jeanne Kriek


    Full Text Available In this pilot study, we sought to examine the influence of the beliefs of Grade 10 to 12 physical science teachers on their intended and actual usage of interactive simulations (Physics Education Technology, or PhET in their classrooms. A combination of the Theory of Planned Behaviour, the Technology Acceptance Model and the Innovation Diffusion Theory was used to examine the influence of teachers' attitudes, subjective norms and perceived behavioural control on their intention to use simulations in their classrooms. Using regression and factor analyses, it was found that beliefs about the perceived usefulness and the pedagogical compatibility of PhET have a significant effect on teachers' attitude towards the use of the simulations in their classrooms. The expectations of the teachers' colleagues contribute to the subjective norm of these teachers. The regression and partial correlation result also highlights the importance of teachers' general technology proficiency. Although we were not able to confirm a direct link between attitudes, subjective norm, perceived behavioural control, and the teachers' behaviour intention we show the influence of behaviour intention on the actual use of the simulations with an accuracy of 70.83%.

  3. A Preliminary Examination of the Relationship Between Social Networking Interactions, Internet Use, and Thwarted Belongingness. (United States)

    Moberg, Fallon B; Anestis, Michael D


    Joiner's (2005) interpersonal-psychological theory of suicide hypothesizes that suicidal desire develops in response to the joint presence of thwarted belongingness and perceived burdensomeness. To consider the potential influence of online interactions and behaviors on these outcomes. To address this, we administered an online protocol assessing suicidal desire and online interactions in a sample of 305 undergraduates (83.6% female). We hypothesized negative interactions on social networking sites and a preference for online social interactions would be associated with thwarted belongingness. We also conducted an exploratory analysis examining the associations between Internet usage and perceived burdensomeness. Higher levels of negative interactions on social networking sites, but no other variables, significantly predicted thwarted belongingness. Our exploratory analysis showed that none of our predictors were associated with perceived burdensomeness after accounting for demographics, depression, and thwarted belongingness. Our findings indicate that a general tendency to have negative interactions on social networking sites could possibly impact suicidal desire and that these effects are significant above and beyond depression symptoms. Furthermore, no other aspect of problematic Internet use significantly predicted our outcomes in multivariate analyses, indicating that social networking in particular may have a robust effect on thwarted belongingness.

  4. Simulated Interactive Research Experiments as Educational Tools for Advanced Science (United States)

    Tomandl, Mathias; Mieling, Thomas; Losert-Valiente Kroon, Christiane M.; Hopf, Martin; Arndt, Markus


    Experimental research has become complex and thus a challenge to science education. Only very few students can typically be trained on advanced scientific equipment. It is therefore important to find new tools that allow all students to acquire laboratory skills individually and independent of where they are located. In a design-based research process we have investigated the feasibility of using a virtual laboratory as a photo-realistic and scientifically valid representation of advanced scientific infrastructure to teach modern experimental science, here, molecular quantum optics. We found a concept based on three educational principles that allows undergraduate students to become acquainted with procedures and concepts of a modern research field. We find a significant increase in student understanding using our Simulated Interactive Research Experiment (SiReX), by evaluating the learning outcomes with semi-structured interviews in a pre/post design. This suggests that this concept of an educational tool can be generalized to disseminate findings in other fields.

  5. Numerical Simulation of Tower Rotor Interaction for Downwind Wind Turbine

    Directory of Open Access Journals (Sweden)

    Isam Janajreh


    Full Text Available Downwind wind turbines have lower upwind rotor misalignment, and thus lower turning moment and self-steered advantage over the upwind configuration. In this paper, numerical simulation to the downwind turbine is conducted to investigate the interaction between the tower and the blade during the intrinsic passage of the rotor in the wake of the tower. The moving rotor has been accounted for via ALE formulation of the incompressible, unsteady, turbulent Navier-Stokes equations. The localized CP, CL, and CD are computed and compared to undisturbed flow evaluated by Panel method. The time history of the CP, aerodynamic forces (CL and CD, as well as moments were evaluated for three cross-sectional tower; asymmetrical airfoil (NACA0012 having four times the rotor's chord length, and two circular cross-sections having four and two chords lengths of the rotor's chord. 5%, 17%, and 57% reductions of the aerodynamic lift forces during the blade passage in the wake of the symmetrical airfoil tower, small circular cross-section tower and large circular cross-section tower were observed, respectively. The pronounced reduction, however, is confined to a short time/distance of three rotor chords. A net forward impulsive force is also observed on the tower due to the high speed rotor motion.

  6. Implementation of interactive virtual simulation of physical systems (United States)

    Sanchez, H.; Escobar, J. J.; Gonzalez, J. D.; Beltran, J.


    Considering the limited availability of laboratories for physics teaching and the difficulties this causes in the learning of school students in Santa Marta Colombia, we have developed software in order to generate greater student interaction with the phenomena physical and improve their understanding. Thereby, this system has been proposed in an architecture Model/View- View- Model (MVVM), sharing the benefits of MVC. Basically, this pattern consists of 3 parts: The Model, that is responsible for business logic related. The View, which is the part with which we are most familiar and the user sees. Its role is to display data to the user and allowing manipulation of the data of the application. The ViewModel, which is the middle part of the Model and the View (analogous to the Controller in the MVC pattern), as well as being responsible for implementing the behavior of the view to respond to user actions and expose data model in a way that is easy to use links to data in the view. .NET Framework 4.0 and editing package Silverlight 4 and 5 are the main requirements needed for the deployment of physical simulations that are hosted in the web application and a web browser (Internet Explorer, Mozilla Firefox or Chrome). The implementation of this innovative application in educational institutions has shown that students improved their contextualization of physical phenomena.

  7. Flight Dynamic Simulation with Nonlinear Aeroelastic Interaction using the ROM-ROM Procedure Project (United States)

    National Aeronautics and Space Administration — ZONA Technology, Inc. proposes to develop an integrated flight dynamics simulation capability with nonlinear aeroelastic interactions by combining a flight dynamics...

  8. Flight Dynamic Simulation with Nonlinear Aeroelastic Interaction using the ROM-ROM Procedure Project (United States)

    National Aeronautics and Space Administration — ZONA Technology, Inc. (ZONA) proposes to develop an integrated flight dynamics simulation capability with nonlinear aeroelastic interactions by combining a flight...

  9. Jointly they edit: examining the impact of community identification on political interaction in Wikipedia.

    Directory of Open Access Journals (Sweden)

    Jessica J Neff

    Full Text Available BACKGROUND: In their 2005 study, Adamic and Glance coined the memorable phrase 'divided they blog', referring to a trend of cyberbalkanization in the political blogosphere, with liberal and conservative blogs tending to link to other blogs with a similar political slant, and not to one another. As political discussion and activity increasingly moves online, the power of framing political discourses is shifting from mass media to social media. METHODOLOGY/PRINCIPAL FINDINGS: Continued examination of political interactions online is critical, and we extend this line of research by examining the activities of political users within the Wikipedia community. First, we examined how users in Wikipedia choose to display their political affiliation. Next, we analyzed the patterns of cross-party interaction and community participation among those users proclaiming a political affiliation. In contrast to previous analyses of other social media, we did not find strong trends indicating a preference to interact with members of the same political party within the Wikipedia community. CONCLUSIONS/SIGNIFICANCE: Our results indicate that users who proclaim their political affiliation within the community tend to proclaim their identity as a 'Wikipedian' even more loudly. It seems that the shared identity of 'being Wikipedian' may be strong enough to triumph over other potentially divisive facets of personal identity, such as political affiliation.

  10. Jointly they edit: examining the impact of community identification on political interaction in Wikipedia. (United States)

    Neff, Jessica J; Laniado, David; Kappler, Karolin E; Volkovich, Yana; Aragón, Pablo; Kaltenbrunner, Andreas


    In their 2005 study, Adamic and Glance coined the memorable phrase 'divided they blog', referring to a trend of cyberbalkanization in the political blogosphere, with liberal and conservative blogs tending to link to other blogs with a similar political slant, and not to one another. As political discussion and activity increasingly moves online, the power of framing political discourses is shifting from mass media to social media. Continued examination of political interactions online is critical, and we extend this line of research by examining the activities of political users within the Wikipedia community. First, we examined how users in Wikipedia choose to display their political affiliation. Next, we analyzed the patterns of cross-party interaction and community participation among those users proclaiming a political affiliation. In contrast to previous analyses of other social media, we did not find strong trends indicating a preference to interact with members of the same political party within the Wikipedia community. Our results indicate that users who proclaim their political affiliation within the community tend to proclaim their identity as a 'Wikipedian' even more loudly. It seems that the shared identity of 'being Wikipedian' may be strong enough to triumph over other potentially divisive facets of personal identity, such as political affiliation.

  11. A fully-coupled fluid-structure interaction simulation of cerebral aneurysms (United States)

    Bazilevs, Y.; Hsu, M.-C.; Zhang, Y.; Wang, W.; Liang, X.; Kvamsdal, T.; Brekken, R.; Isaksen, J. G.


    This paper presents a computational vascular fluid-structure interaction (FSI) methodology and its application to patient-specific aneurysm models of the middle cerebral artery bifurcation. A fully coupled fluid-structural simulation approach is reviewed, and main aspects of mesh generation in support of patient-specific vascular FSI analyses are presented. Quantities of hemodynamic interest such as wall shear stress and wall tension are studied to examine the relevance of FSI modeling as compared to the rigid arterial wall assumption. We demonstrate the importance of including the flexible wall modeling in vascular blood flow simulations by performing a comparison study that involves four patient-specific models of cerebral aneurysms varying in shape and size.

  12. Modelling phosphorus (P), sulphur (S) and iron (Fe) interactions during the simulation of anaerobic digestion processes

    DEFF Research Database (Denmark)

    Flores-Alsina, Xavier; Solon, Kimberly; Kazadi-Mbamba, Christian


    This paper examines the effects of different model formulations when describing sludge stabilization processes in wastewater treatment plants by the Anaerobic Digestion Model No. 1 (ADM1). The proposed model extensions describe the interactions amongst phosphorus (P), sulfur (S), iron (Fe......) and their potential effect on total biogas production (CO2, CH4, H2 and H2S). The ADM1 version, implemented in the plant-wide context provided by the Benchmark Simulation Model No. 2 (BSM2), is used as the basic platform (A0). Four (A1 – A4) different model extensions are implemented, simulated and evaluated....... The first approach (A1) considers P transformations by accounting for the kinetic decay of polyphosphates (XPP) and potential uptake of Volatile Fatty Acids (VFA) to produce Polyhydroxyalkanoates (XPHA) by Phosphorus Accumulating Organisms (XPAO). The second model formulation (A2) describes biological...

  13. Virtual standardized patients: an interactive method to examine variation in depression care among primary care physicians (United States)

    Hooper, Lisa M.; Weinfurt, Kevin P.; Cooper, Lisa A.; Mensh, Julie; Harless, William; Kuhajda, Melissa C.; Epstein, Steven A.


    Background Some primary care physicians provide less than optimal care for depression (Kessler et al., Journal of the American Medical Association 291, 2581–90, 2004). However, the literature is not unanimous on the best method to use in order to investigate this variation in care. To capture variations in physician behaviour and decision making in primary care settings, 32 interactive CD-ROM vignettes were constructed and tested. Aim and method The primary aim of this methods-focused paper was to review the extent to which our study method – an interactive CD-ROM patient vignette methodology – was effective in capturing variation in physician behaviour. Specifically, we examined the following questions: (a) Did the interactive CD-ROM technology work? (b) Did we create believable virtual patients? (c) Did the research protocol enable interviews (data collection) to be completed as planned? (d) To what extent was the targeted study sample size achieved? and (e) Did the study interview protocol generate valid and reliable quantitative data and rich, credible qualitative data? Findings Among a sample of 404 randomly selected primary care physicians, our voice-activated interactive methodology appeared to be effective. Specifically, our methodology – combining interactive virtual patient vignette technology, experimental design, and expansive open-ended interview protocol – generated valid explanations for variations in primary care physician practice patterns related to depression care. PMID:20463864

  14. Examining ecological validity in social interaction: problems of visual fidelity, gaze, and social potential. (United States)

    Reader, Arran T; Holmes, Nicholas P


    Social interaction is an essential part of the human experience, and much work has been done to study it. However, several common approaches to examining social interactions in psychological research may inadvertently either unnaturally constrain the observed behaviour by causing it to deviate from naturalistic performance, or introduce unwanted sources of variance. In particular, these sources are the differences between naturalistic and experimental behaviour that occur from changes in visual fidelity (quality of the observed stimuli), gaze (whether it is controlled for in the stimuli), and social potential (potential for the stimuli to provide actual interaction). We expand on these possible sources of extraneous variance and why they may be important. We review the ways in which experimenters have developed novel designs to remove these sources of extraneous variance. New experimental designs using a 'two-person' approach are argued to be one of the most effective ways to develop more ecologically valid measures of social interaction, and we suggest that future work on social interaction should use these designs wherever possible.

  15. Controlling simulations of human-artifact interaction with scenario bundles

    NARCIS (Netherlands)

    Van der Vegte, W.F.; Rusák, Z.


    We introduce a methodology for modeling and simulating fully virtual human-artifact systems, aiming to resolve two issues in virtual prototyping: (i) integration of distinct modeling and simulation approaches, and (ii) extending the deployability of simulations towards conceptual design. We are

  16. 77 FR 24537 - Draft Standards and Best Practices for Interaction Between Medical Examiner/Coroner and Organ and... (United States)


    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF JUSTICE Office of Justice Programs Draft Standards and Best Practices for Interaction Between Medical Examiner... entitled, ``Organ and Tissue Procurement Committee Standards and Best Practices for Interaction Between...

  17. An Interactive Simulator for Imposing Virtual Musculoskeletal Dynamics. (United States)

    Hasson, Christopher


    Disease processes are often marked by both neural and muscular changes that alter movement control and execution, but these adaptations are difficult to tease apart because they occur simultaneously. This is addressed by swapping an individual's limb dynamics with a neurally-controlled facsimile using an interactive musculoskeletal simulator (IMS) that allows controlled modifications of musculoskeletal dynamics. This paper details the design and operation of the IMS, quantifies and describes human adaptation to the IMS, and determines whether the IMS allows users to move naturally, a prerequisite for manipulation experiments. Healthy volunteers (n = 4) practiced a swift goal-directed task (back-and-forth elbow flexion/extension) for 90 trials with the IMS off (normal dynamics) and 240 trials with the IMS on, i.e. the actions of a user's personalized electromyography-driven musculoskeletal model are robotically imposed back on to the user. After practicing with the IMS on, subjects could complete the task with end-point errors of 1.56°, close to the speed-matched IMS-off error of 0.57°. Muscle activity, joint torque, and arm kinematics for IMS-on and -off conditions were well matched for three subjects (root-meansquared error [RMSE] = 0.16 Nm), but the error was higher for one subject with a small stature (RMSE = 0.25 Nm). A well-matched musculoskeletal model allowed IMS users to perform a goal-directed task nearly as well as when the IMS was not active. This advancement permits real-time manipulations of musculoskeletal dynamics, which could increase our understanding of muscular and neural co-adaptations to injury, disease, disuse, and aging.

  18. Fluid-structure interaction simulation of an avian flight model. (United States)

    Ruck, Sebastian; Oertel, Herbert


    A three-dimensional numerical avian model was developed to investigate the unsteady and turbulent aerodynamic performance of flapping wings for varying wingbeat frequencies and flow velocities (up to 12 Hz and 9 m s(-1)), corresponding to a reduced frequency range of k=0.22 to k=1.0 and a Reynolds number range of Re=16,000 to Re=50,000. The wings of the bird-inspired model consist of an elastic membrane. Simplifying the complicated locomotion kinematics to a sinusoidal wing rotation about two axes, the main features of dynamic avian flight were approximated. Numerical simulation techniques of fluid-structure interaction (FSI) providing a fully resolved flow field were applied to calculate the aerodynamic performance of the flapping elastic wings with the Reynolds averaged Navier-Stokes (RANS) approach. The results were used to characterize and describe the macroscopic flow configurations in terms of starting, stopping, trailing and bound vortices. For high reduced frequencies up to k=0.67 it was shown that the wake does not consist of individual vortex rings known as the discrete vortex ring gait. Rather, the wake is dominated by a chain of elliptical vortex rings on each wing. The structures are interlocked at the starting and stopping vortices, which are shed in pairs at the reversal points of the wingbeat cycle. For decreasing reduced frequency, the results indicate a transition to a continuous vortex gait. The upstroke becomes more aerodynamically active, leading to a consistent circulation of the bound vortex on the wing and a continuous spanwise shedding of small scale vortices. The formation of the vortices shed spanwise in pairs at the reversal points is reduced and the wake is dominated by the tip and root vortices, which form long drawn-out vortex structures.

  19. Interaction of Aldehyde dehydrogenase with acetaminophen as examined by spectroscopies and molecular docking

    Directory of Open Access Journals (Sweden)

    Ayodele O. Kolawole


    Full Text Available The interaction of acetaminophen, a non-substrate anionic ligand, with Aldehyde Dehydrogenase was studied by fluorescence, UV–Vis absorption, and circular dichroism spectroscopies under simulated physiological conditions. The fluorescence spectra and data generated showed that acetaminophen binding to ALDH is purely dynamic quenching mechanism. The acetaminophen-ALDH is kinetically rapid reversible interaction with a binding constant, Ka, of 4.91×103 L mol−1. There was an existence of second binding site of ALDH for acetaminophen at saturating acetaminophen concentration. The binding sites were non-cooperative. The thermodynamic parameters obtained suggest that Van der Waal force and hydrogen bonding played a major role in the binding of acetaminophen to ALDH. The interaction caused perturbation of the ALDH structures with an obvious reduction in the α-helix. The binding distance of 4.43 nm was obtained between Acetaminophen and ALDH. Using Ficoll 400 as macro-viscosogen and glycerol as micro-viscosogen, Stoke-Einstein empirical plot demonstrated that acetaminophen-ALDH binding was diffusion controlled. Molecular docking showed the participation of some amino acids in the complex formation with −5.3 kcal binding energy. With these, ALDH might not an excipient detoxifier of acetaminophen but could be involved in its pegylation/encapsulation.

  20. Grid-size dependence of Cauchy boundary conditions used to simulate stream-aquifer interactions (United States)

    Mehl, S.; Hill, M.C.


    This work examines the simulation of stream–aquifer interactions as grids are refined vertically and horizontally and suggests that traditional methods for calculating conductance can produce inappropriate values when the grid size is changed. Instead, different grid resolutions require different estimated values. Grid refinement strategies considered include global refinement of the entire model and local refinement of part of the stream. Three methods of calculating the conductance of the Cauchy boundary conditions are investigated. Single- and multi-layer models with narrow and wide streams produced stream leakages that differ by as much as 122% as the grid is refined. Similar results occur for globally and locally refined grids, but the latter required as little as one-quarter the computer execution time and memory and thus are useful for addressing some scale issues of stream–aquifer interactions. Results suggest that existing grid-size criteria for simulating stream–aquifer interactions are useful for one-layer models, but inadequate for three-dimensional models. The grid dependence of the conductance terms suggests that values for refined models using, for example, finite difference or finite-element methods, cannot be determined from previous coarse-grid models or field measurements. Our examples demonstrate the need for a method of obtaining conductances that can be translated to different grid resolutions and provide definitive test cases for investigating alternative conductance formulations.

  1. Examining dynamic interactions among experimental factors influencing hydrologic data assimilation with the ensemble Kalman filter (United States)

    Wang, S.; Huang, G. H.; Baetz, B. W.; Cai, X. M.; Ancell, B. C.; Fan, Y. R.


    The ensemble Kalman filter (EnKF) is recognized as a powerful data assimilation technique that generates an ensemble of model variables through stochastic perturbations of forcing data and observations. However, relatively little guidance exists with regard to the proper specification of the magnitude of the perturbation and the ensemble size, posing a significant challenge in optimally implementing the EnKF. This paper presents a robust data assimilation system (RDAS), in which a multi-factorial design of the EnKF experiments is first proposed for hydrologic ensemble predictions. A multi-way analysis of variance is then used to examine potential interactions among factors affecting the EnKF experiments, achieving optimality of the RDAS with maximized performance of hydrologic predictions. The RDAS is applied to the Xiangxi River watershed which is the most representative watershed in China's Three Gorges Reservoir region to demonstrate its validity and applicability. Results reveal that the pairwise interaction between perturbed precipitation and streamflow observations has the most significant impact on the performance of the EnKF system, and their interactions vary dynamically across different settings of the ensemble size and the evapotranspiration perturbation. In addition, the interactions among experimental factors vary greatly in magnitude and direction depending on different statistical metrics for model evaluation including the Nash-Sutcliffe efficiency and the Box-Cox transformed root-mean-square error. It is thus necessary to test various evaluation metrics in order to enhance the robustness of hydrologic prediction systems.

  2. Examining gene-environment interactions in comorbid depressive and disruptive behavior disorders using a Bayesian approach. (United States)

    Adrian, Molly; Kiff, Cara; Glazner, Chris; Kohen, Ruth; Tracy, Julia Helen; Zhou, Chuan; McCauley, Elizabeth; Vander Stoep, Ann


    The objective of this study was to apply a Bayesian statistical analytic approach that minimizes multiple testing problems to explore the combined effects of chronic low familial support and variants in 12 candidate genes on risk for a common and debilitating childhood mental health condition. Bayesian mixture modeling was used to examine gene by environment interactions among genetic variants and environmental factors (family support) associated in previous studies with the occurrence of comorbid depression and disruptive behavior disorders youth, using a sample of 255 children. One main effect, variants in the oxytocin receptor (OXTR, rs53576) was associated with increased risk for comorbid disorders. Two significant gene × environment and one signification gene × gene interactions emerged. Variants in the nicotinic acetylcholine receptor α5 subunit (CHRNA5, rs16969968) and in the glucocorticoid receptor chaperone protein FK506 binding protein 5 (FKBP5, rs4713902) interacted with chronic low family support in association with child mental health status. One gene × gene interaction, 5-HTTLPR variant of the serotonin transporter (SERT/SLC6A4) in combination with μ opioid receptor (OPRM1, rs1799971) was associated with comorbid depression and conduct problems. Results indicate that Bayesian modeling is a feasible strategy for conducting behavioral genetics research. This approach, combined with an optimized genetic selection strategy (Vrieze et al., 2012), revealed genetic variants involved in stress regulation (FKBP5, SERT × OPMR), social bonding (OXTR), and nicotine responsivity (CHRNA5) in predicting comorbid status. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Examining Gene-Environment Interactions in Comorbid Depressive and Disruptive Behavior Disorders using a Bayesian Approach (United States)

    Adrian, Molly; Kiff, Cara; Glazner, Chris; Kohen, Ruth; Tracy, Julia Helen; Zhou, Chuan; McCauley, Elizabeth; Stoep, Ann Vander


    Objective The objective of this study was to apply a Bayesian statistical analytic approach that minimizes multiple testing problems to explore the combined effects of chronic low familial support and variants in 12 candidate genes on risk for a common and debilitating childhood mental health condition. Method Bayesian mixture modeling was used to examine gene by environment interactions among genetic variants and environmental factors (family support) associated in previous studies with the occurrence of comorbid depression and disruptive behavior disorders youth, using a sample of 255 children. Results One main effects, variants in the oxytocin receptor (OXTR, rs53576) was associated with increased risk for comorbid disorders. Two significant gene x environment and one signification gene x gene interaction emerged. Variants in the nicotinic acetylcholine receptor α5 subunit (CHRNA5, rs16969968) and in the glucocorticoid receptor chaperone protein FK506 binding protein 5 (FKBP5, rs4713902) interacted with chronic low family support in association with child mental health status. One gene x gene interaction, 5-HTTLPR variant of the serotonin transporter (SERT/SLC6A4) in combination with μ opioid receptor (OPRM1, rs1799971) was associated with comorbid depression and conduct problems. Conclusions Results indicate that Bayesian modeling is a feasible strategy for conducting behavioral genetics research. This approach, combined with an optimized genetic selection strategy (Vrieze, Iacono, & McGue, 2012), revealed genetic variants involved in stress regulation ( FKBP5, SERTxOPMR), social bonding (OXTR), and nicotine responsivity (CHRNA5) in predicting comorbid status. PMID:26228411

  4. Examining alcohol and alcohol-free versions of a Simulated Drinking Game Procedure. (United States)

    Silvestri, Mark M; Cameron, Jennifer M; Borsari, Brian; Correia, Christopher J


    Drinking games contribute to heavy drinking on college campuses because the rules often result in rapid alcohol consumption and increased risk of negative consequences. The current study used the Simulated Drinking Game Procedure (SDGP) to observe and describe drinking game behavior under controlled laboratory conditions. Participants (N = 40) age of 21 and older played a laboratory version of beer pong. Participants were randomly assigned to play with either beer or water, and the study examined the differences in consumption, blood alcohol concentration (BAC) estimates, and subjective experiences within and across the beverage conditions. Participants in both beverage conditions viewed the sessions as realistic simulations of actual drinking games. Participants who played with beer consumed more drinks and refused fewer drinks than those served water. Two measures of BAC (calculated formula and breath alcohol device) were correlated with one another and with the amount of alcohol consumed. BAC estimates based on the formula tended to be higher than readings obtained from the breath alcohol device, and the discrepancies between the two measures were higher among female participants. The findings suggest that both the alcohol and alcohol-free versions of the SDGP are safe and ecologically valid research tools for examining drinking game behavior. The study highlights the features and limitations of both versions of the SDGP and provides a platform for continued development of the methodology, allowing researchers to address a range of clinically relevant research questions.

  5. Examining elementary school children's level of enjoyment of traditional tag games vs. interactive dance games. (United States)

    Gao, Zan; Zhang, Peng; Podlog, Leslie William


    Enjoyment has been implicated as a determinant of physical activity among children and adolescents. However, the effect of different sport activities on children's enjoyment remains largely unexplored. This study examined whether children's enjoyment in physical education (PE) varied as a function of learning activities. Participants were 210 third- through sixth-grade children who had a 30 min PE class every week. Participants responded to a standardized self-report enjoyment survey measuring their enjoyment level in a PE class during which they participated in tag games. Students completed the same questionnaire when involved in interactive dance games in PE. The results revealed that children reported significantly higher scores in enjoyment toward interactive dance games than they did toward traditional games (p dance games than boys did (p dance games into PE.

  6. Using interactive model simulations in co-design : An experiment in urban design

    NARCIS (Netherlands)

    Steen, M.G.D.; Arendsen, J.; Cremers, A.H.M.; Vries, A. de; Jong, J.M.G. de; Koning, N.M. de


    This paper presents an experiment in which people performed a co-design task in urban design, using a multi-user touch table application with or without interactive model simulations. We hypothesised that using the interactive model simulations would improve communication and co-operation between

  7. An Evaluation of Computer-Based Interactive Simulations in the Assessment of Statistical Concepts (United States)

    Neumann, David L.; Hood, Michelle; Neumann, Michelle M.


    In a previous report, Neumann (2010) described the use of interactive computer-based simulations in the assessment of statistical concepts. This assessment approach combined declarative knowledge of statistics with experiences in interacting with computer-based simulations. The aim of the present study was to conduct a systematic evaluation of the…

  8. Simulation of interaction between wind farm and power system

    DEFF Research Database (Denmark)

    Sørensen, Poul Ejnar; Hansen, Anca Daniela; Janosi, L.


    A dynamic model of the wind farm Hagesholm has been implemented in the dedicated power system simulation program DIgSILENT. The wind farm con- sists of six 2MW NM2000/72 wind turbines from NEG-Micon. The model has been verified using simultaneous powerquality measurements on the 10 kV terminals...... of a single wind turbine and power performance measurements on two wind turbines. The verification shows a generally good agreement between simulations and measurements, although the simulations at higher windspeeds seem to underestimate the power and voltage fluctuations. A way to improve the simulation...

  9. Simulation Architecture for Modelling Interaction Between User and Elbow-articulated Exoskeleton

    NARCIS (Netherlands)

    Kruif, B.J. de; Schmidhauser, E.; Stadler, K.S.; O'Sullivan, L.W.


    The aim of our work is to improve the existing user-exoskeleton models by introducing a simulation architecture that can simulate its dynamic interaction, thereby altering the initial motion of the user. A simulation architecture is developed that uses the musculoskeletal models from OpenSim, and

  10. An Interactive Teaching System for Bond Graph Modeling and Simulation in Bioengineering (United States)

    Roman, Monica; Popescu, Dorin; Selisteanu, Dan


    The objective of the present work was to implement a teaching system useful in modeling and simulation of biotechnological processes. The interactive system is based on applications developed using 20-sim modeling and simulation software environment. A procedure for the simulation of bioprocesses modeled by bond graphs is proposed and simulators…

  11. A prospective comparison between written examination and either simulation-based or oral viva examination of intensive care trainees' procedural skills. (United States)

    Nunnink, L; Venkatesh, B; Krishnan, A; Vidhani, K; Udy, A


    We compared results of written assessment of intensive care trainees' procedural skills with results obtained from one of two live assessment formats for the purposes of assessing the concurrent validity of the different test methods. Forty-five Australasian senior trainees in intensive care medicine completed a written test relating to a procedural skill, as well as either a simulation format or oral viva assessment on the same procedural skill. We analysed correlation between written exam results and results obtained from simulation format or oral viva assessment. For those who completed the simulation format examination, we also maintained a narrative of actions and identified critical errors. There was limited correlation between written exam results and live (simulation or viva) procedure station results (r = 0.31). Correlation with written exam results was very low for simulation format assessments (r = 0.08) but moderate for oral viva format assessment (r = 0.58). Participants who passed a written exam based on management of a blocked tracheostomy scenario performed a number of dangerous errors when managing a simulated patient in that scenario. The lack of correlation between exam formats supports multi-modal assessment, as currently it is not known which format best represents workplace performance. Correlation between written and oral viva results may indicate redundancy between those test formats, whereas limited correlation between simulation and written exams may support the use of both formats as part of an integrated assessment strategy. We hypothesise that identification of critical candidate errors in a simulation format exam that were not exposed in a written exam may indicate better predictive validity for simulation format examination of procedural skills.

  12. Fluid-structure interaction involving dynamic wetting: 2D modeling and simulations (United States)

    Liu, Hao-Ran; Gao, Peng; Ding, Hang


    In this paper, we propose a hybrid model to compute the capillary force acting on moving solid objects, and combine it with the diffuse-interface immersed-boundary method in Liu and Ding (2015) [18] to simulate fluid-structure interaction (FSI) involving dynamic wetting. Dynamic wetting is very important in the dynamic interaction between fluid-fluid interfaces and small moving objects. Numerical simulations of these flow problems require accurate computation of the capillary force acting on the structure, which depends on the instantaneous position of and the effective surface tension at the moving contact line. In order to achieve this, we use the diffuse-interface immersed-boundary method to simulate the dynamic wetting on moving objects, and propose a hybrid model to compute the effective surface tension at the contact line. Specifically, a diffuse interface model is used for the interface profile out of equilibrium, e.g. at the onset of formation or detachment of contact lines, and a sharp interface model is used for the interface profile at equilibrium. The performance of the method is examined by a variety of numerical experiments. We simulate the sinking of a circular cylinder due to gravity, and study the capillarity-dominated impact dynamics of a solid sphere on a water pool. In both cases the numerical results are quantitatively compared against the experimental data, and good agreements have been achieved. The momentum conservation of the system is carefully checked by studying head-on collision between a drop and a solid sphere. Finally, we apply the method to the self-assembly process of multiple floating cylinders on water surface.

  13. Turbulence Simulation of Laboratory Wind-Wave Interaction in High Winds and Upscaling to Ocean Conditions (United States)


    by gale force and stronger winds. This project seeks to reconcile laboratory and field measurements of wind-wave interaction and surface drag in...December 2016 Award Number: N00014-12-10184 Turbulence Simulation of Laboratory Wind-Wave Interaction in High Winds and Upscaling to Ocean...modulational properties appears warranted. Our simulations did not account for: long wave-short wave interactions which may impact strongly on

  14. Examining the Psychological Effect of Rape Acknowledgment: The Interaction of Acknowledgment Status and Ambivalent Sexism. (United States)

    Wilson, Laura C; Miller, Katherine E; Leheney, Emma K; Ballman, Alesha D; Scarpa, Angela


    Although the majority of rape survivors do not label their experiences as rape (i.e., unacknowledged rape), the literature is mixed in terms of how this affects survivors' psychological functioning. To elucidate the discrepancies, the present study examined the interaction between rape acknowledgement and ambivalent sexism in relation to depression and posttraumatic stress disorder (PTSD) symptoms. The analyzed sample included 128 female rape survivors who were drawn from a larger college sample of 1,595 participants. The participants completed measures of sexual assault experiences, ambivalent sexism, and depression and PTSD symptoms. The results supported a significant interaction between acknowledgement status and benevolent sexism in relation to both depression and PTSD symptoms. Conversely, the present study failed to find support for an interaction between acknowledgment status and hostile sexism. The clinical implications suggest that rather than seeing acknowledging rape as essential to the recovery process, clinicians should assess for and take into account other factors that may contribute to psychological functioning. Additionally, the findings support that more complex models of trauma recovery should be investigated with the goal of working toward a more comprehensive understanding of the longitudinal process of rape acknowledgment. © 2016 Wiley Periodicals, Inc.

  15. Comparing High Definition Live Interactive and Store-and-Forward Consultations to In-Person Examinations. (United States)

    Marchell, Richard; Locatis, Craig; Burges, Gene; Maisiak, Richard; Liu, Wei-Li; Ackerman, Michael


    There is little teledermatology research directly comparing remote methods, even less research with two in-person dermatologist agreement providing a baseline for comparing remote methods, and no research using high definition video as a live interactive method. To compare in-person consultations with store-and-forward and live interactive methods, the latter having two levels of image quality. A controlled study was conducted where patients were examined in-person, by high definition video, and by store-and-forward methods. The order patients experienced methods and residents assigned methods rotated, although an attending always saw patients in-person. The type of high definition video employed, lower resolution compressed or higher resolution uncompressed, was alternated between clinics. Primary and differential diagnoses, biopsy recommendations, and diagnostic and biopsy confidence ratings were recorded. Concordance and confidence were significantly better for in-person versus remote methods and biopsy recommendations were lower. Store-and-forward and higher resolution uncompressed video results were similar and better than those for lower resolution compressed video. Dermatology residents took store-and-forward photos and their quality was likely superior to those normally taken in practice. There were variations in expertise between the attending and second and third year residents. The superiority of in-person consultations suggests the tendencies to order more biopsies or still see patients in-person are often justified in teledermatology and that high resolution uncompressed video can close the resolution gap between store-and-forward and live interactive methods.

  16. Postimpact examinations of three DOP 4 iridium shells from simulant fuel sphere assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Cramer, E.M.; Hecker, S.S.


    Three fuel sphere assemblies, with thoria in doped iridium containment shells, were examined after a simulated earth impact from an aborted orbital mission of a multihundred-watt thermoelectric heat source. The extent of deformation of each unit was measured. Damage to the containment shells was minimal in comparison to that in undoped iridium. Metallographic sections from critical areas indicated that superficial grain boundary cracking in weld zones and microscopic cracking in regions of maximum diameter had occurred in addition to local thinning and coining. The improved properties of the doped iridium are attributed to the retention of a small grain size and to an additional fracture resistance over iridium of a comparable grain size, imparted by either a change in grain boundary chemistry or the flow characteristics of the doped material.

  17. Weldability examination of ASTM A 240 S41500 martensitic stainless steel by thermal cycles simulation testings

    Directory of Open Access Journals (Sweden)

    Alberto Velázquez-del Rosario


    Full Text Available The weldability assets of ASTM A 240 S41500 (ASTM A 240/A 240M martensitic stainless steel are presented through the study of the effects of single and double thermal weld cycles on mechanical properties and microstructure of base metal (BM and the artificial heat affected zone (HAZ created by thermal weld simulations. For single cycles, separate peak temperatures of 1000 ºC/12 s and 1350 ºC/12 s (cooling times: 12 s in both cases were evaluated, whilst two combinations of peak temperatures: (1350 ºC/5 s + 1000 ºC/5 s ºC and (1350 ºC/12 s + 1000 ºC/12 s ºC (cooling times: 5 s and 12 s, were applied for double cycles. Post weld heat treatment (PWHT with short and long holding times were applied and Vickers hardness, impact toughness and metallographic examinations were used in order to assess mechanical and metallographic properties in the as-simulated (no heat treated and postweld heat treated conditions. Best properties of the welded joint for double thermal weld cycles with long holding times were reached, which reveals the good weldability and applicability of the tested material in post weld heat treated conditions.

  18. An examination of the relationship between measures of impulsivity and risky simulated driving amongst young drivers. (United States)

    Hatfield, Julie; Williamson, Ann; Kehoe, E James; Prabhakharan, Prasannah


    The risky driving of young drivers may owe in part to youthful motivations (such as experience-seeking, authority rebellion, desire for peer approval) combined with incompletely developed impulse control. Although self-reported impulsiveness has been positively associated with self-reports of risky driving, results based on objective measures of response inhibition (e.g., Go/No-go tasks) have been inconclusive. The present study examined interrelationships between measures of response inhibition, self-report impulsiveness scales, and responses to events during a simulated drive that were designed to detect impulsive, unsafe behaviours (e.g., turning across on-coming traffic). Participants were 72 first-year Psychology students. More speeding and "Unsafe" responding to critical events during simulated driving were associated with poorer impulse control as assessed by commission errors during a Go/No-Go task. These results consolidate evidence for a relationship between impulse control and risky driving amongst young drivers. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Supporting hypothesis generation by learners exploring an interactive computer simulation

    NARCIS (Netherlands)

    van Joolingen, Wouter; de Jong, Anthonius J.M.


    Computer simulations provide environments enabling exploratory learning. Research has shown that these types of learning environments are promising applications of computer assisted learning but also that they introduce complex learning settings, involving a large number of learning processes. This

  20. Apparatus and method for interaction phenomena with world modules in data-flow-based simulation (United States)

    Xavier, Patrick G [Albuquerque, NM; Gottlieb, Eric J [Corrales, NM; McDonald, Michael J [Albuquerque, NM; Oppel, III, Fred J.


    A method and apparatus accommodate interaction phenomenon in a data-flow-based simulation of a system of elements, by establishing meta-modules to simulate system elements and by establishing world modules associated with interaction phenomena. World modules are associated with proxy modules from a group of meta-modules associated with one of the interaction phenomenon. The world modules include a communication world, a sensor world, a mobility world, and a contact world. World modules can be further associated with other world modules if necessary. Interaction phenomenon are simulated in corresponding world modules by accessing member functions in the associated group of proxy modules. Proxy modules can be dynamically allocated at a desired point in the simulation to accommodate the addition of elements in the system of elements such as a system of robots, a system of communication terminals, or a system of vehicles, being simulated.

  1. Examining publication bias—a simulation-based evaluation of statistical tests on publication bias (United States)


    Background Publication bias is a form of scientific misconduct. It threatens the validity of research results and the credibility of science. Although several tests on publication bias exist, no in-depth evaluations are available that examine which test performs best for different research settings. Methods Four tests on publication bias, Egger’s test (FAT), p-uniform, the test of excess significance (TES), as well as the caliper test, were evaluated in a Monte Carlo simulation. Two different types of publication bias and its degree (0%, 50%, 100%) were simulated. The type of publication bias was defined either as file-drawer, meaning the repeated analysis of new datasets, or p-hacking, meaning the inclusion of covariates in order to obtain a significant result. In addition, the underlying effect (β = 0, 0.5, 1, 1.5), effect heterogeneity, the number of observations in the simulated primary studies (N = 100, 500), and the number of observations for the publication bias tests (K = 100, 1,000) were varied. Results All tests evaluated were able to identify publication bias both in the file-drawer and p-hacking condition. The false positive rates were, with the exception of the 15%- and 20%-caliper test, unbiased. The FAT had the largest statistical power in the file-drawer conditions, whereas under p-hacking the TES was, except under effect heterogeneity, slightly better. The CTs were, however, inferior to the other tests under effect homogeneity and had a decent statistical power only in conditions with 1,000 primary studies. Discussion The FAT is recommended as a test for publication bias in standard meta-analyses with no or only small effect heterogeneity. If two-sided publication bias is suspected as well as under p-hacking the TES is the first alternative to the FAT. The 5%-caliper test is recommended under conditions of effect heterogeneity and a large number of primary studies, which may be found if publication bias is examined in a discipline

  2. Examining publication bias—a simulation-based evaluation of statistical tests on publication bias

    Directory of Open Access Journals (Sweden)

    Andreas Schneck


    Full Text Available Background Publication bias is a form of scientific misconduct. It threatens the validity of research results and the credibility of science. Although several tests on publication bias exist, no in-depth evaluations are available that examine which test performs best for different research settings. Methods Four tests on publication bias, Egger’s test (FAT, p-uniform, the test of excess significance (TES, as well as the caliper test, were evaluated in a Monte Carlo simulation. Two different types of publication bias and its degree (0%, 50%, 100% were simulated. The type of publication bias was defined either as file-drawer, meaning the repeated analysis of new datasets, or p-hacking, meaning the inclusion of covariates in order to obtain a significant result. In addition, the underlying effect (β = 0, 0.5, 1, 1.5, effect heterogeneity, the number of observations in the simulated primary studies (N = 100, 500, and the number of observations for the publication bias tests (K = 100, 1,000 were varied. Results All tests evaluated were able to identify publication bias both in the file-drawer and p-hacking condition. The false positive rates were, with the exception of the 15%- and 20%-caliper test, unbiased. The FAT had the largest statistical power in the file-drawer conditions, whereas under p-hacking the TES was, except under effect heterogeneity, slightly better. The CTs were, however, inferior to the other tests under effect homogeneity and had a decent statistical power only in conditions with 1,000 primary studies. Discussion The FAT is recommended as a test for publication bias in standard meta-analyses with no or only small effect heterogeneity. If two-sided publication bias is suspected as well as under p-hacking the TES is the first alternative to the FAT. The 5%-caliper test is recommended under conditions of effect heterogeneity and a large number of primary studies, which may be found if publication bias is examined in a

  3. Interaction of Polar and Nonpolar Organic Pollutants with Soil Organic Matter: Sorption Experiments and Molecular Dynamics Simulation

    CERN Document Server

    Ahmed, Ashour A; Aziz, Saadullah G; Hilal, Rifaat H; Elroby, Shaaban A; Al-Youbi, Abdulrahman O; Leinweber, Peter; Kühn, Oliver


    The fate of organic pollutants in the environment is influenced by several factors including the type and strength of their interactions with soil components especially SOM. However, a molecular level answer to the question How organic pollutants interact with SOM? is lacking. In order to explore mechanisms of this interaction, we have developed a new SOM model followed by carrying out molecular dynamics (MD) simulations in parallel with sorption experiments. The new SOM model comprises free SOM functional groups (carboxylic acid and naphthalene) as well as SOM cavities (with two different sizes), representing the soil voids, containing the same SOM functional groups. To examine the effect of the hydrophobicity on the interaction, the organic pollutants hexachlorobenzene (HCB, non-polar) and sulfanilamide (SAA, polar) were considered. The experimental and the theoretical outcomes explored four major points regarding sorption of SAA and HCB on soil. 1. The interaction depends on the SOM chemical composition mo...

  4. Numerical Simulation of Rocket Exhaust Interaction with Lunar Soil (United States)

    Liever, Peter; Tosh, Abhijit; Curtis, Jennifer


    This technology development originated from the need to assess the debris threat resulting from soil material erosion induced by landing spacecraft rocket plume impingement on extraterrestrial planetary surfaces. The impact of soil debris was observed to be highly detrimental during NASA s Apollo lunar missions and will pose a threat for any future landings on the Moon, Mars, and other exploration targets. The innovation developed under this program provides a simulation tool that combines modeling of the diverse disciplines of rocket plume impingement gas dynamics, granular soil material liberation, and soil debris particle kinetics into one unified simulation system. The Unified Flow Solver (UFS) developed by CFDRC enabled the efficient, seamless simulation of mixed continuum and rarefied rocket plume flow utilizing a novel direct numerical simulation technique of the Boltzmann gas dynamics equation. The characteristics of the soil granular material response and modeling of the erosion and liberation processes were enabled through novel first principle-based granular mechanics models developed by the University of Florida specifically for the highly irregularly shaped and cohesive lunar regolith material. These tools were integrated into a unique simulation system that accounts for all relevant physics aspects: (1) Modeling of spacecraft rocket plume impingement flow under lunar vacuum environment resulting in a mixed continuum and rarefied flow; (2) Modeling of lunar soil characteristics to capture soil-specific effects of particle size and shape composition, soil layer cohesion and granular flow physics; and (3) Accurate tracking of soil-borne debris particles beginning with aerodynamically driven motion inside the plume to purely ballistic motion in lunar far field conditions. In the earlier project phase of this innovation, the capabilities of the UFS for mixed continuum and rarefied flow situations were validated and demonstrated for lunar lander rocket


    Directory of Open Access Journals (Sweden)

    T. O. Aubakirov


    Full Text Available A technique of calculation of aircraft condensation trails (contrails and wake vortices interaction is described. The technique is based on a suitable for real-time applications mathematical model of far wake utilizes the method of discrete vortices. The technique is supplemented by account of the influence of axial velocities in the vortex nucleus on contrail and wake vortex location. Results of calculations of contrails and wake vortices interaction for Il-76 and B-747 aircraft are presented.


    Directory of Open Access Journals (Sweden)

    Nina P. Dementievska


    Full Text Available Physics teachers should have professional competences, aimed at the use of online technologies associated with physical experiments. Lack of teaching materials for teachers in Ukrainian language leads to the use of virtual laboratories and computer simulations by traditional methods of education, not by the latest innovative modern educational technology, which may limit their use and greatly reduce their effectiveness. Ukrainian teaching literature has practically no information about the assessment of competencies, research skills of students for the laboratory activities. The aim of the article is to describe some components of instructional design for the Web site with simulations in school physical experiments and their evaluation.

  7. Examination of climatological wind patterns and simulated pollen dispersion in a complex island environment. (United States)

    Viner, Brian J; Arritt, Raymond W; Westgate, Mark E


    Complex terrain creates small-scale circulations which affect pollen dispersion but may be missed by meteorological observing networks and coarse-grid meteorological models. On volcanic islands, these circulations result from differing rates of surface heating between land and sea as well as rugged terrain. We simulated the transport of bentgrass, ryegrass, and maize pollen from 30 sources within the agricultural regions of the Hawaiian island Kaua'i during climatological conditions spanning season conditions and the La Niña, El Niño, and neutral phases of the El Niño-Southern Oscillation. Both pollen size and source location had major effects on predicted dispersion over and near the island. Three patterns of pollen dispersion were identified in response to prevailing wind conditions: southwest winds transported pollen inland, funneling pollen grains through valleys; east winds transported pollen over the ocean, with dispersive tails for the smallest pollen grains following the mean wind and extending as far as the island of Ni'ihau 35 km away; and northeast winds moved pollen inland counter to the prevailing flow due to a sea breeze circulation that formed over the source region. These results are the first to predict the interactions between complex island terrain and local climatology on grass pollen dispersion. They demonstrate how numerical modeling can provide guidance for field trials by illustrating the common flow regimes present in complex terrain, allowing field trials to focus on areas where successful sampling is more likely to occur.

  8. Examination of climatological wind patterns and simulated pollen dispersion in a complex island environment (United States)

    Viner, Brian J.; Arritt, Raymond W.; Westgate, Mark E.


    Complex terrain creates small-scale circulations which affect pollen dispersion but may be missed by meteorological observing networks and coarse-grid meteorological models. On volcanic islands, these circulations result from differing rates of surface heating between land and sea as well as rugged terrain. We simulated the transport of bentgrass, ryegrass, and maize pollen from 30 sources within the agricultural regions of the Hawaiian island Kaua'i during climatological conditions spanning season conditions and the La Niña, El Niño, and neutral phases of the El Niño-Southern Oscillation. Both pollen size and source location had major effects on predicted dispersion over and near the island. Three patterns of pollen dispersion were identified in response to prevailing wind conditions: southwest winds transported pollen inland, funneling pollen grains through valleys; east winds transported pollen over the ocean, with dispersive tails for the smallest pollen grains following the mean wind and extending as far as the island of Ni'ihau 35 km away; and northeast winds moved pollen inland counter to the prevailing flow due to a sea breeze circulation that formed over the source region. These results are the first to predict the interactions between complex island terrain and local climatology on grass pollen dispersion. They demonstrate how numerical modeling can provide guidance for field trials by illustrating the common flow regimes present in complex terrain, allowing field trials to focus on areas where successful sampling is more likely to occur.

  9. Raman microspectroscopy for in situ examination of carbon-microbe-mineral interactions (United States)

    Creamer, C.; Foster, A. L.; Lawrence, C. R.; Mcfarland, J. W.; Waldrop, M. P.


    The changing paradigm of soil organic matter formation and turnover is focused at the nexus of microbe-carbon-mineral interactions. However, visualizing biotic and abiotic stabilization of C on mineral surfaces is difficult given our current techniques. Therefore we investigated Raman microspectroscopy as a potential tool to examine microbially mediated organo-mineral associations. Raman microspectroscopy is a non-destructive technique that has been used to identify microorganisms and minerals, and to quantify microbial assimilation of 13C labeled substrates in culture. We developed a partial least squares regression (PLSR) model to accurately quantify (within 5%) adsorption of four model 12C substrates (glucose, glutamic acid, oxalic acid, p-hydroxybenzoic acid) on a range of soil minerals. We also developed a PLSR model to quantify the incorporation of 13C into E. coli cells. Using these two models, along with measures of the 13C content of respired CO2, we determined the allocation of glucose-derived C into mineral-associated microbial biomass and respired CO2 in situ and through time. We observed progressive 13C enrichment of microbial biomass with incubation time, as well as 13C enrichment of CO2 indicating preferential decomposition of glucose-derived C. We will also present results on the application of our in situ chamber to quantify the formation of organo-mineral associations under both abiotic and biotic conditions with a variety of C and mineral substrates, as well as the rate of turnover and stabilization of microbial residues. Application of Raman microspectroscopy to microbial-mineral interactions represents a novel method to quantify microbial transformation of C substrates and subsequent mineral stabilization without destructive sampling, and has the potential to provide new insights to our conceptual understanding of carbon-microbe-mineral interactions.

  10. Effects of an interactive simulation material for clinical dentistry on knowledge acquisition. (United States)

    Miyoshi, Tomoe; Hobo, Koki; Sunaga, Masayo; Kinoshita, Atsuhiro


    The aim of this study was to examine the effectiveness of interactive simulation materials with decision making in knowledge acquisition and anxiety reduction. Dental students in their fourth year at Tokyo Medical and Dental University were randomly divided into Groups I and D. Participants read a scenario, learned with interactive-type (Group I) or display-type (Group D) learning materials about pulpectomy, and took the State-Trait Anxiety Inventory-JYZ, a quiz for measuring learning effects, and a questionnaire for evaluation of the material. Except for requesting decision making in the interactive-type material, the contents of both materials were the same. The results were compared using the unpaired Student's t-test, Fisher's exact test, and the two-way repeated measures ANOVA with the Bonferroni post hoc test. The mean quiz score was significantly higher in Group I than in Group D (I: 75.4±1.4, D: 60.6±2.7, pknowledge acquisition.

  11. Numerical simulation of species dependent interaction in a polluted ...

    African Journals Online (AJOL)

    In this study, we have utilized a sound numerical simulation technique to derive the conditions under which a legally-binding control related policy is necessary in order to mitigate the endemic Niger Delta polluted environmental issue. The implication of this present analysis if implemented will have several benefits for the ...

  12. Simulating market dynamics : Interactions between consumer psychology and social networks

    NARCIS (Netherlands)

    Janssen, M.A; Jager, W.


    Markets can show different types of dynamics, from quiet markets dominated by one or a few products, to markets with continual penetration of new and reintroduced products. in a previous article we explored the dynamics of markets from a psychological perspective using a multi-agent simulation

  13. Plasma-material interaction under simulated disruption conditions

    Energy Technology Data Exchange (ETDEWEB)

    Arkhipov, N.I. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Bakhtin, V.P. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Safronov, V.M. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Toporkov, D.A. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Vasenin, S.G. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Wurz, H. [Kernforschungszentrum Karlsruhe, INR (Germany); Zhitlukhin, A.M. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation)


    Sudden evaporation of divertor plate surface under high heat load during tokamak plasma disruption instantaneously produces a vapor shield. The cloud of vaporized material prevents the divertor plates from the bulk of incoming energy flux and thus reduces the further material erosion. Dynamics and effectiveness of the vapor shield are studied experimentally at the 2MK-200 facility under simulated disruption conditions. (orig.).

  14. Connected Chemistry--Incorporating Interactive Simulations into the Chemistry Classroom. (United States)

    Stieff, Mike; Wilensky, Uri


    Describes a novel modeling and simulation package and assesses its impact on students' understanding of chemistry. Connected Chemistry was implemented inside the NetLogo modeling environment. Using Connected Chemistry, students employed problem -solving techniques characterized by stronger attempts at conceptual understanding and logical…

  15. Good experiences with interactive temporal bone surgical simulator

    DEFF Research Database (Denmark)

    Andersen, Steven A W; Mikkelsen, Peter Trier; Noe, Karsten Ostergaard


    time. In a multilingual user interface the integrated tutor function provides stepwise instructions during drilling through an intuitive, volumetric approach. A censor function draws on metrics derived from the simulator to provide instant and summary feedback for the user. The VES can be downloaded...

  16. PhET Interactive Simulations: Transformative Tools for Teaching Chemistry (United States)

    Moore, Emily B.; Chamberlain, Julia M.; Parson, Robert; Perkins, Katherine K.


    Developing fluency across symbolic-, macroscopic-, and particulate-level representations is central to learning chemistry. Within the chemistry education community, animations and simulations that support multi-representational fluency are considered critical. With advances in the accessibility and sophistication of technology,…

  17. Evaluation of dentinal fluid flow behaviours: a fluid-structure interaction simulation. (United States)

    Su, Kuo-Chih; Chuang, Shu-Fen; Ng, Eddie Yin-Kwee; Chang, Chih-Han


    This study uses the fluid-structure interaction (FSI) method to investigate the fluid flow in dental pulp. First, the FSI method is used for the biomechanical simulation of dental intrapulpal responses during force loading (50, 100 and 150 N) on a tooth. The results are validated by comparison with experimental outcomes. Second, the FSI method is used to investigate an intact tooth subjected to a mechanical stimulus during loading at various loading rates. Force loading (0-100 N) is applied gradually to an intact tooth surface with loading rates of 125, 62.5, 25 and 12.5 N/s, respectively, and the fluid flow changes in the pulp are evaluated. FSI analysis is found to be suitable for examining intrapulpal biomechanics. An external force applied to a tooth with a low loading rate leads to a low fluid flow velocity in the pulp chamber, thus avoiding tooth pain.

  18. A laboratory simulation of mesoscale flow interaction with the Alps (United States)

    Ferrero, E.; Longhetto, A.; Briatore, L.; Chabert d'Hieres, G.; Didelle, H.; Giraud, C.; Gleizon, P.


    A series of laboratory experiments, aimed at the simulation of some aspects of Alpine lee cyclogenesis has been carried out in the rotating tank of the Coriolis Laboratory of LEGI-IMG in Grenoble. Dynamic and thermodynamic processes, typical of baroclinic development triggered by the orography, were simulated. The background flow simulating the basic state of the atmosphere consisted of a stream of intermediate density fluid introduced at the interface between two fluid layers. The structure of the intermediate current was established by mixing fluid obtained from the upper layer of fresh water with fluid removed from the heavier salty layer below. The dynamical similarity parameters are the Rossby ( Ro), Burger ( Bu) and Ekman ( Ek) numbers, although this last, owing to its small values, need not be matched between model and prototype, since viscous effects are not important for small time scales. The flow in both the prototype and laboratory simulation is characterized by hydrostatics; this requires ( Ro2δ2/ Bu)≪1 (where δ= H/ L is the aspect ratio of the obstacle) which is clearly satisfied, in the atmosphere and oceans, and for the laboratory experiment. A range of experiments for various Rossby and Burger numbers were conducted which delimited the region of parameter space for which background flows akin to that found to the northwest of the Alps prior to baroclinic cyclogenesis events, were observed. One such experiment was carried out by placing a model of the Alps at the appropriate place in the flow field. The subsequent motion in the laboratory was observed and dye tracer motions were used to obtain the approximate particle trajectories. The density field was also analyzed to provide the geopotential field of the simulated atmosphere. Using standard transformations from the similarity analysis, the laboratory observations were related to the prototype atmosphere. The flow and the geopotential fields gave results compatible with the particular

  19. Interactions with parents and friends among chronically ill children: examining social networks. (United States)

    Herzer, Michele; Umfress, Kris; Aljadeff, Gabriel; Ghai, Kanika; Zakowski, Sandra G


    Children with medical conditions often experience a combination of positive and negative social interactions with parents and friends. Adult research examining cross-domain buffering effects has documented that supportive social ties can make up for shortcomings in other social relationships. This study examined whether negative effects of strained relationships with loved ones can be buffered when children feel supported by individuals in different support networks (i.e., cross-domain buffering effects). Children with Type I diabetes (n = 56), chronic asthma (n = 54), and cystic fibrosis (n = 17) completed questionnaires during an outpatient hospital visit that assessed perceptions of support and strain from parents and friends, quality of life, self-concept, and emotional/behavioral difficulties. Parental strain was conceptualized as parental overprotection and parental rejection. Hierarchical regression analyses showed that friend support buffered the adverse effects of parental strain on child quality of life, self-concept, and emotional/behavioral difficulties. Interestingly, parental support did not buffer the negative effects of experiencing strained relationships with friends; only main effects on outcome were found. These findings partially support our hypotheses of cross-domain buffering. In this study, friendships were a protective factor for children who experienced strained relationships with parents. In contrast, although parent support had a direct impact on child outcome, it did not make up for feeling rejected by friends. Because close relationships are often strained during medical stressors, findings underscore the importance of promoting social connectedness in chronically ill children to maximize opportunities for experiencing positive social relationships.

  20. MHD Simulations of Magnetospheric Accretion, Ejection and Plasma-field Interaction

    Directory of Open Access Journals (Sweden)

    Romanova M. M.


    Full Text Available We review recent axisymmetric and three-dimensional (3D magnetohydrodynamic (MHD numerical simulations of magnetospheric accretion, plasma-field interaction and outflows from the disk-magnetosphere boundary.

  1. Social interaction, globalization and computer-aided analysis a practical guide to developing social simulation

    CERN Document Server

    Osherenko, Alexander


    This thorough, multidisciplinary study discusses the findings of social interaction and social simulation using understandable global examples. Shows the reader how to acquire intercultural data, illustrating each step with descriptive comments and program code.

  2. Particle-in-Cell Simulations of Plasma Interaction with Lunar Crustal Magnetic Anomalies (United States)

    Poppe, A. R.; Halekas, J. S.; Delory, G. T.; Farrell, W. M.


    We present results from a kinetic plasma simulation on the interaction of ambient plasma with lunar crustal magnetic anomalies. We discuss implications of this work for physical phenomena at the Moon, such as lunar swirls and proton implantation.

  3. Multiscale GasKinetics/Particle (MGP) Simulation for Rocket Plume/Lunar Dust Interactions Project (United States)

    National Aeronautics and Space Administration — A Multiscale GasKinetic/Particle (MGP) computational method is proposed to simulate the plume-crater-interaction/dust-impingement(PCIDI) problem. The MGP method...

  4. A Framework for the Interactive Handling of High-Dimensional Simulation Data in Complex Geometries

    KAUST Repository

    Benzina, Amal


    Flow simulations around building infrastructure models involve large scale complex geometries, which when discretized in adequate detail entail high computational cost. Moreover, tasks such as simulation insight by steering or optimization require many such costly simulations. In this paper, we illustrate the whole pipeline of an integrated solution for interactive computational steering, developed for complex flow simulation scenarios that depend on a moderate number of both geometric and physical parameters. A mesh generator takes building information model input data and outputs a valid cartesian discretization. A sparse-grids-based surrogate model—a less costly substitute for the parameterized simulation—uses precomputed data to deliver approximated simulation results at interactive rates. Furthermore, a distributed multi-display visualization environment shows building infrastructure together with flow data. The focus is set on scalability and intuitive user interaction.

  5. Favouritism in the motor system: Social interaction modulates action simulation

    NARCIS (Netherlands)

    Kourtis, D.; Sebanz, N.; Knoblich, G.K.


    The ability to anticipate others' actions is crucial for social interaction. It has been shown that this ability relies on motor areas of the human brain that are not only active during action execution and action observation, but also during anticipation of another person's action. Recording

  6. Microscopic observations of needle and soft-tissue simulant interactions

    NARCIS (Netherlands)

    Jahya, Alex; Misra, Sarthak


    Currently, physicians have no means of correctly estimating the needle tip location during percutaneous needle insertion. A model of needle-tissue interaction that predicts the needle tip location would assist physicians in pre-operative planning and hence improve needle targeting accuracy. This

  7. Humans, computers and wizards human (simulated) computer interaction

    CERN Document Server

    Fraser, Norman; McGlashan, Scott; Wooffitt, Robin


    Using data taken from a major European Union funded project on speech understanding, the SunDial project, this book considers current perspectives on human computer interaction and argues for the value of an approach taken from sociology which is based on conversation analysis.

  8. Molecular simulations of lipid-mediated protein-protein interactions

    NARCIS (Netherlands)

    de Meyer, F.J.M.; Venturoli, M.; Smit, B.


    Recent experimental results revealed that lipid-mediated interactions due to hydrophobic forces may be important in determining the protein topology after insertion in the membrane, in regulating the protein activity, in protein aggregation and in signal transduction. To gain insight into the

  9. Numerical simulation of premixed flames interacting with obstacles

    NARCIS (Netherlands)

    Paravento, F.


    In this work the modeling of the interaction of a premixed flame with one ore more obstacles of different shape is considered. The challenge of this work was to design a fast numerical tool suitable for a standard personal computer. A tool able to use a simplified chemical model that removes the

  10. Numerical simulation of SMART-1 Hall-thruster plasma interactions

    NARCIS (Netherlands)

    Tajmar, Martin; Sedmik, René; Scharlemann, Carsten


    SMART-1 has been the first European mission using a Hall thruster to reach the moon. An onboard plasma diagnostic package allowed a detailed characterization of the thruster exhaust plasma and its interactions with the spacecraft. Analysis of in-flight data revealed, amongst others, an unpredicted

  11. Interactive Acoustic Simulation in Urban and Complex Environments (United States)


    P., Noe, N., and Gaudaire, F. Calculation of tyre noise radiation with a mixed approach. Acta Acustica united with Acustica 94, 1 (2008), 91–103. [73...radiation and scattering problems. Acta Acustica united with Acustica 81, 6 (1995), 528–543. [85] Kuttruff, H. Room acoustics. CRC Press, 2009. [86...10-12 (2010), 1296–1318. [104] Ochmann, M. The source simulation technique for acoustic radiation problems. Acta Acustica united with Acustica 81, 6

  12. Simulating conventions and norms under local interactions and imitation


    Ille, Sebastian


    This paper is based on Ille 2013. Both papers analyze the same model, but in contrast, this paper does not provide an analytical solution but rather resorts to simulations. This allows the reader, who is familiar with the former article, to retrace the results more thoroughly and without the requirement of a sophisticated mathematical background. Additionally, this paper illustrates the dynamics of the setting. Focus is placed on 2 × 2 Nash coordination games on a two-dimensional lattice. Pla...

  13. Perspectives: Using Results from HRSA's Health Workforce Simulation Model to Examine the Geography of Primary Care. (United States)

    Streeter, Robin A; Zangaro, George A; Chattopadhyay, Arpita


    Inform health planning and policy discussions by describing Health Resources and Services Administration's (HRSA's) Health Workforce Simulation Model (HWSM) and examining the HWSM's 2025 supply and demand projections for primary care physicians, nurse practitioners (NPs), and physician assistants (PAs). HRSA's recently published projections for primary care providers derive from an integrated microsimulation model that estimates health workforce supply and demand at national, regional, and state levels. Thirty-seven states are projected to have shortages of primary care physicians in 2025, and nine states are projected to have shortages of both primary care physicians and PAs. While no state is projected to have a 2025 shortage of primary care NPs, many states are expected to have only a small surplus. Primary care physician shortages are projected for all parts of the United States, while primary care PA shortages are generally confined to Midwestern and Southern states. No state is projected to have shortages of all three provider types. Projected shortages must be considered in the context of baseline assumptions regarding current supply, demand, provider-service ratios, and other factors. Still, these findings suggest geographies with possible primary care workforce shortages in 2025 and offer opportunities for targeting efforts to enhance workforce flexibility. © Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  14. Doctor-patient relationship as motivation and outcome: examining uses of an Interactive Cancer Communication System. (United States)

    Shaw, Bret R; Han, Jeong Yeob; Hawkins, Robert P; Stewart, James; McTavish, Fiona; Gustafson, David H


    To examine how the pre-existing doctor-patient relationship predicts conceptually distinct service use within an Interactive Cancer Communication System (ICCS) for underserved women with breast cancer and in turn how service utilization influences the doctor-patient relationship. Study sample included 231 recently diagnosed, lower income breast cancer patients. Participants were provided a free computer, Internet access and training in how to use an ICCS called the Comprehensive Health Enhancement Support System (CHESS) "Living with Breast Cancer" program. Survey data was collected at pre-test and 4-months after using the system, and use data about how women used the system was also collected. The only statistically significant predictor of service use was that patients with a more negative appraisal about the doctor-patient relationship used the Ask an Expert service more frequently, and there were trends toward a more negative appraisal of the doctor-patient relationship being associated with higher use of Information and Interactive services. Conversely, there was a trend toward a more positive appraisal predicting higher use of the Discussion Group service. In terms of statistically significant effects, more frequent utilization of Information services was associated with a more positive appraisal of the doctor relationship. While a more negative perception of the doctor-patient relationships at pre-test was associated with higher use of most of the conceptually distinct services within this ICCS, use of the Information services was associated with having a more positive appraisal of the doctor-patient relationship at post-test suggesting that high-quality information on the Internet can serve to improve patients' satisfaction with their doctor.

  15. Increasing Learner Retention in a Simulated Learning Network using Indirect Social Interaction

    NARCIS (Netherlands)

    Koper, Rob


    Please refer to original publication: Koper, E.J.R. (2005). Increasing Learner Retention in a Simulated Learning Network Using Indirect Social Interaction. Journal of Artificial Societies and Social Simulation vol. 8, no. 2. Software is only stored to ensure

  16. Interactive Modeling, Simulation and Control of Large-Scale Crowds and Traffic (United States)

    Lin, Ming C.; Guy, Stephen; Narain, Rahul; Sewall, Jason; Patil, Sachin; Chhugani, Jatin; Golas, Abhinav; van den Berg, Jur; Curtis, Sean; Wilkie, David; Merrell, Paul; Kim, Changkyu; Satish, Nadathur; Dubey, Pradeep; Manocha, Dinesh

    We survey some of our recent work on interactive modeling, simulation, and control of large-scale crowds and traffic for urban scenes. The driving applications of our work include real-time simulation for computer games, virtual environments, and avatar-based online 3D social networks. We also present some preliminary results and proof-of-concept demonstrations.

  17. Turbulence radiation interaction modeling in hydrocarbon pool fire simulations

    Energy Technology Data Exchange (ETDEWEB)



    The importance of turbulent fluctuations in temperature and species concentration in thermal radiation transport modeling for combustion applications is well accepted by the radiation transport and combustion communities. A number of experimental and theoretical studies over the last twenty years have shown that fluctuations in the temperature and species concentrations may increase the effective emittance of a turbulent flame by as much as 50% to 300% over the value that would be expected from the mean temperatures and concentrations. With the possibility of such a large effect on the principal mode of heat transfer from a fire, it is extremely important for fire modeling efforts that turbulence radiation interaction be well characterized and possible modeling approaches understood. Toward this end, this report seeks to accomplish three goals. First, the principal turbulence radiation interaction closure terms are defined. Second, an order of magnitude analysis is performed to understand the relative importance of the various closure terms. Finally, the state of the art in turbulence radiation interaction closure modeling is reviewed. Hydrocarbon pool fire applications are of particular interest in this report and this is the perspective from which this review proceeds. Experimental and theoretical analysis suggests that, for this type of heavily sooting flame, the turbulent radiation interaction effect is dominated by the nonlinear dependence of the Planck function on the temperature. Additional effects due to the correlation between turbulent fluctuations in the absorptivity and temperature may be small relative to the Planck function effect for heavily sooting flames. This observation is drawn from a number of experimental and theoretical discussions. Nevertheless, additional analysis and data is needed to validate this observation for heavily sooting buoyancy dominated plumes.

  18. Interactive Computational Algorithms for Acoustic Simulation in Complex Environments (United States)


    arrays on aerostats, and dynamic routing of surveillance aircraft such as helicopters and UAVs to minimize audibility. (a) Papers published in peer...of this printing . List the papers, including journal references, in the following categories: 30.00 21.00 22.00 24.00 25.00 26.00 14.00 15.00 16.00...Albert, Keith Wilson, Dinesh Manocha. Validation of 3D numerical simulation for acoustic pulse propagation in an urban environment, The Journal of

  19. SOPHIA - Simulation Of PhotoHadronic Interactions in Astrophysics (United States)

    Mucke, A.; Engel, R. R.; Protheroe, R. J.; Rachen, J. P.; Stanev, T.


    We present a new Monte-Carlo event generator for photomeson production of relativistic nucleons in thermal and power-law photon fields. Resonance excitation/decay, direct single-pion production, diffractive scattering and multipion production are used to reproduce the full measured cross section. A complete simulation of the multiparticle final states from the photopion production threshold up to very high energies is performed. We show that our event generator SOPHIA can reasonably reproduce all fixed target and collider experimental data available to us.

  20. Associations between young adult romantic relationship quality and problem behaviors : An examination of personality-environment interactions

    NARCIS (Netherlands)

    Yu, Rongqin; Branje, Susan; Keijsers, Loes; Meeus, W.H.J.

    This longitudinal study examined person–environment interplay by testing interaction effects between adolescent personality type (i.e., overcontrollers, undercontrollers, and resilients) and young adult romantic relationship quality on young adult delinquency and anxiety. The study employed six

  1. A Tool to Simulate the Transmission, Reception, and Execution of Interactive TV Applications. (United States)

    Carvalho Marques Neto, Manoel; Kulesza, Raoni; Rodrigues, Thiago; Machado, Felipe A L; Santos, Celso A S


    The emergence of Interactive Digital Television (iDTV) opened a set of technological possibilities that go beyond those offered by conventional TV. Among these opportunities we can highlight interactive contents that run together with linear TV program (television service where the viewer has to watch a scheduled TV program at the particular time it is offered and on the particular channel it is presented on). However, developing interactive contents for this new platform is not as straightforward as, for example, developing Internet applications. One of the options to make this development process easier and safer is to use an iDTV simulator. However, after having investigated some of the existing iDTV simulation environments, we have found a limitation: these simulators mainly present solutions focused on the TV receiver, whose interactive content must be loaded in advance by the programmer to a local repository (e.g., Hard Drive, USB). Therefore, in this paper, we propose a tool, named BiS (Broadcast iDTV content Simulator), which makes possible a broader solution for the simulation of interactive contents. It allows simulating the transmission of interactive content along with the linear TV program (simulating the transmission of content over the air and in broadcast to the receivers). To enable this, we defined a generic and easy-to-customize communication protocol that was implemented in the tool. The proposed environment differs from others because it allows simulating reception of both linear content and interactive content while running Java applications to allow such a content presentation.

  2. A Tool to Simulate the Transmission, Reception, and Execution of Interactive TV Applications

    Directory of Open Access Journals (Sweden)

    Manoel Carvalho Marques Neto


    Full Text Available The emergence of Interactive Digital Television (iDTV opened a set of technological possibilities that go beyond those offered by conventional TV. Among these opportunities we can highlight interactive contents that run together with linear TV program (television service where the viewer has to watch a scheduled TV program at the particular time it is offered and on the particular channel it is presented on. However, developing interactive contents for this new platform is not as straightforward as, for example, developing Internet applications. One of the options to make this development process easier and safer is to use an iDTV simulator. However, after having investigated some of the existing iDTV simulation environments, we have found a limitation: these simulators mainly present solutions focused on the TV receiver, whose interactive content must be loaded in advance by the programmer to a local repository (e.g., Hard Drive, USB. Therefore, in this paper, we propose a tool, named BiS (Broadcast iDTV content Simulator, which makes possible a broader solution for the simulation of interactive contents. It allows simulating the transmission of interactive content along with the linear TV program (simulating the transmission of content over the air and in broadcast to the receivers. To enable this, we defined a generic and easy-to-customize communication protocol that was implemented in the tool. The proposed environment differs from others because it allows simulating reception of both linear content and interactive content while running Java applications to allow such a content presentation.

  3. Behavioral and physiological reactions in dogs to a veterinary examination: Owner-dog interactions improve canine well-being. (United States)

    Csoltova, Erika; Martineau, Michaël; Boissy, Alain; Gilbert, Caroline


    In order to improve well-being of dogs during veterinary visits, we aimed to investigate the effect of human social interactions on behavior and physiology during routine examination. Firstly, we assessed the impact of a standardized veterinary examination on behavioral and physiological indicators of stress in dogs. Secondly, we examined whether the owner's tactile and verbal interactions with the dog influenced behavioral and physiological stress-associated parameters. A randomized within-subjects crossover design was used to examine behavior (n=33), rectal temperature (n=33), heart rate (HR) (n=18), maximal ocular surface temperature (max OST) (n=13) and salivary cortisol concentrations (n=10) in healthy privately owned pet dogs. The study consisted of two experimental conditions: a) "contact" - owner petting and talking to the dog during the examination; b) "non-contact" - owner present during the examination but not allowed to interact with the dog. Our findings showed that the veterinary examinations produced acute stress responses in dogs during both "contact" and "non-contact" conditions, with significant increases in lip licking, HR, and max OST. A significant decrease in attempts to jump off the examination table (p=0.002) was observed during the examination in the "contact" compared to the "non-contact" condition. In addition, interactions of owners showed an attenuating effect on HR (p=0.018) and max OST (p=0.011) in their dogs. The testing order (first vs. second visit) had no impact on behavioral and physiological parameters, suggesting that dogs did not habituate or sensitize to the examination procedure. Moreover, the duration of the owner-dog interactions had no significant impact on the behavioral and physiological responses of their dogs. This study demonstrates that owner-dog interactions improve the well-being of dogs during a veterinary examination. Future research may assist in further understanding the mechanisms associated with reducing

  4. Informal Learning in Academic Student Organizations: An Exploratory Examination of Student-Faculty Interactions and the Relationship to Leadership (United States)

    Holzweiss, Peggy C.; Parrott, Kelli Peck; Cole, Bryan R.


    This exploratory study examined informal learning opportunities that exist within student organizations. The researchers specifically isolated academic organizations and the interactions between students and faculty that may occur in this context. Findings indicate that 81% of participants experienced interactions with faculty within the context…

  5. What counts as effective communication in nursing? Evidence from nurse educators' and clinicians' feedback on nurse interactions with simulated patients. (United States)

    O'Hagan, Sally; Manias, Elizabeth; Elder, Catherine; Pill, John; Woodward-Kron, Robyn; McNamara, Tim; Webb, Gillian; McColl, Geoff


    To examine the feedback given by nurse educators and clinicians on the quality of communication skills of nurses in interactions with simulated patients. The quality of communication in interactions between nurses and patients has a major influence on patient outcomes. To support the development of effective nursing communication in clinical practice, a good understanding of what constitutes effective communication is helpful. An exploratory design was used involving individual interviews, focus groups and written notes from participants and field notes from researchers to investigate perspectives on nurse-patient communication. Focus groups and individual interviews were held between August 2010-September 2011 with a purposive sample of 15 nurse educators and clinicians who observed videos of interactions between nurses and simulated patients. These participants were asked to give oral feedback on the quality and content of these interactions. Verbatim transcriptions were undertaken of all data collected. All written notes and field notes were also transcribed. Thematic analysis of the data was undertaken. Four major themes related to nurse-patient communication were derived from the educators' and clinicians' feedback: approach to patients and patient care, manner towards patients, techniques used for interacting with patients and generic aspects of communication. This study has added to previous research by contributing grounded evidence from a group of nurse educators and clinicians on the aspects of communication that are relevant for effective nurse-patient interactions in clinical practice. © 2013 John Wiley & Sons Ltd.

  6. 3d particle simulations on ultra short laser interaction

    Energy Technology Data Exchange (ETDEWEB)

    Nishihara, Katsunobu; Okamoto, Takashi; Yasui, Hidekazu [Osaka Univ., Suita (Japan). Inst. of Laser Engineering


    Two topics related to ultra short laser interaction with matter, linear and nonlinear high frequency conductivity of a solid density hydrogen plasma and anisotropic self-focusing of an intense laser in an overdense plasma, have been investigated with the use of 3-d particle codes. Frequency dependence of linear conductivity in a dense plasma is obtained, which shows anomalous conductivity near plasma frequency. Since nonlinear conductivity decreases with v{sub o}{sup -3}, where v{sub o} is a quivering velocity, an optimum amplitude exists leading to a maximum electron heating. Anisotropic self-focusing of a linear polarized intense laser is observed in an overdense plasma. (author)

  7. Simulations of defect-interface interactions in GaN

    Energy Technology Data Exchange (ETDEWEB)

    Chisholm, J.A.; Bristowe, P.D.


    The authors report on the interaction of native point defects with commonly observed planar defects in GaN. Using a pair potential model they find a positive binding energy for all native defects to the three boundary structures investigated indicating a preference for native defects to form in these interfaces. The binding energy is highest for the Ga interstitial and lowest for vacancies. Interstitials, which are not thought to occur in significant concentrations in bulk GaN, should form in the (11{bar 2}0) IDB and the (10{bar 1}0) SMB and consequently alter the electronic structure of these boundaries.

  8. Molecular Dynamic Simulations of Interaction of an AFM Probe with the Surface of an SCN Sample (United States)

    Bune, Adris; Kaukler, William; Rose, M. Franklin (Technical Monitor)


    Molecular dynamic (MD) simulations is conducted in order to estimate forces of probe-substrate interaction in the Atomic Force Microscope (AFM). First a review of available molecular dynamic techniques is given. Implementation of MD simulation is based on an object-oriented code developed at the University of Delft. Modeling of the sample material - succinonitrile (SCN) - is based on the Lennard-Jones potentials. For the polystyrene probe an atomic interaction potential is used. Due to object-oriented structure of the code modification of an atomic interaction potential is straight forward. Calculation of melting temperature is used for validation of the code and of the interaction potentials. Various fitting parameters of the probe-substrate interaction potentials are considered, as potentials fitted to certain properties and temperature ranges may not be reliable for the others. This research provides theoretical foundation for an interpretation of actual measurements of an interaction forces using AFM.

  9. Flow-Structure-Acoustic Interaction Simulation of Vocalization of a Non-song Bird (United States)

    Jiang, Weili; Zheng, Xudong; Xue, Qian; Have Rasmussen, Jeppe; Elemans, Coen; Complex Flow Modeling; Simulation Lab Team; Elemans Lab Team


    The myoelastic-aerodynamic mechanism of vocalization was recently evidenced in birds across a wide range of taxa, which, for a long time, was believed to generate sound based on the aerodynamic whistle mechanism. The objective of the current study is to: (1) develop a first-principle based, flow-structure-acoustics (FSA) interaction computational model of a non-song bird (rock pigeon); (2) strongly validate the computational model by comparing to the experimental data on the same bird model; (3) examine the data so as to generate new insights into the physics of vocalization of birds. In the current approach, a sharp interface immersed boundary method based incompressible flow solver is utilized to model the air flow; A finite element based solid mechanics solver is utilized to model the LVM(lateral vibratory mass) vibration; A high-order immersed boundary method based acoustics solver is utilized to directly compute sound. Geometric structure of the syrinx, including syringeal lumen, LVM, position of tracheal rings, is based on CT scan of a rock pigeon. The LVM is simulated as isotropic material according to the experimental measurements. Simulation setup about the bronchial pressure, static deformation due to air sac pressure also follows the setup in the experiments. Results including the fundamental frequency, air flow rate, gap, vibration shape will be analyzed and compared to the experimental data.

  10. How to Augment the Learning Impact of Computer Simulations? The Designs and Effects of Interactivity and Scaffolding (United States)

    Chang, Hsin-Yi


    Two investigations were conducted in this study. In the first experiment, the effects of two types of interactivity with a computer simulation were compared: experimentation versus observation interactivity. Experimentation interactivity allows students to use simulations to conduct virtual experiments, whereas observation interactivity allows…

  11. Interactions in charged colloidal suspensions: A molecular dynamics simulation study (United States)

    Padidela, Uday Kumar; Behera, Raghu Nath


    Colloidal suspensions are extensively used in everyday life and find several applications in the pharmaceutical, chemical, food industries, etc. We present the classical molecular dynamics simulation results of the structural and transport properties of charged colloidal suspensions as a function of its size, charge and concentration. The system is viewed as a two-component (colloids and counterions) primitive model consisting of spherical colloid particle (macroion) and the counterions (micro-particles), which are treated explicitly. The solvent is treated as dielectric continuum. A systematic trend in the radial distribution functions g(r), potential of mean force W(r), different thermodynamic properties and diffusion coefficients is obtained as a function of colloid charge, size and concentration. An attractive minimum in W(r) is obtained at short interparticle distance.

  12. Modeling and Simulation of Microelectrode-Retina Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Beckerman, M


    The goal of the retinal prosthesis project is the development of an implantable microelectrode array that can be used to supply visually-driven electrical input to cells in the retina, bypassing nonfunctional rod and cone cells, thereby restoring vision to blind individuals. This goal will be achieved through the study of the fundamentals of electrical engineering, vision research, and biomedical engineering with the aim of acquiring the knowledge needed to engineer a high-density microelectrode-tissue hybrid sensor that will restore vision to millions of blind persons. The modeling and simulation task within this project is intended to address the question how best to stimulate, and communicate with, cells in the retina using implanted microelectrodes.

  13. Interaction between the neoclassical equilibrium and microturbulence in gyrokinetic simulations

    Energy Technology Data Exchange (ETDEWEB)

    Oberparleiter, Michael


    For the application of the nuclear fusion of hydrogen as a heat source for electricity generation understanding of the magnetic fuel confinement is crucial. Most of the cross-field transport in modern-day tokamaks is carried by turbulence driven by steep pressure gradients. Background neoclassical transport, however, provides a steady level of cross-field flux even in cases when turbulence becomes weak or suppressed. The goal of this work is to quantify how neoclassical (NC) effects and turbulence can influence each other. For this purpose the nonlinear gyrokinetic turbulence code GENE is employed. Firstly, its ability to self-consistently calculate the NC radial electric field is successfully benchmarked against the radial force balance equation and NC transport in the plasma region close to the center of a tokamak is studied. In the next step a model system where a long-wavelength external potential is imposed on ion temperature gradient-driven (ITG) turbulence is investigated. It is found that the self-generated shear flow pattern of the turbulence adapts to the imposed pattern and a small external shear is sufficient to notably reduce turbulent transport. Motivated by this global ITG simulations with fixed pressure gradient profiles are performed with and without inclusion of NC effects. Their comparison reveals that the NC field enhances turbulent transport by 20-30 % for a ratio of ion gyroradius and device radius larger than 1/300. An explanation is that the NC field aligns a region of low shear with the maximum of the gradient profile where the turbulent drive is strongest. Further investigation reveals that NC effects also change the dependence of the system on collisionality or safety factor. Finally, in physically more comprehensive simulations with fixed power input and a self-consistently evolving temperature profile, the additional NC transport channel is found to reduce the frequency and amplitude of intermittent turbulent transport bursts.

  14. Interaction of intense laser pulses with atomic clusters: Measurements of ion emission, simulations and applications

    Energy Technology Data Exchange (ETDEWEB)

    Tisch, J.W.G. E-mail:; Hay, N.; Mendham, K.J.; Springate, E.; Symes, D.R.; Comley, A.J.; Mason, M.B.; Gumbrell, E.T.; Ditmire, T.; Smith, R.A.; Marangos, J.P.; Hutchinson, M.H.R


    This review paper provides a general introduction to the interaction of intense (>10{sup 15} W cm{sup -2}), femtosecond laser pulses with atomic clusters in the size range 500-10{sup 5} atoms. A nanoplasma model of the laser-cluster interaction is used to elucidate the underlying physics. Measurements of ion emission from the laser-cluster interaction are presented together with numerical simulations. Emerging applications are described.

  15. Interactive virtual simulation using a 3D computer graphics model for microvascular decompression surgery. (United States)

    Oishi, Makoto; Fukuda, Masafumi; Hiraishi, Tetsuya; Yajima, Naoki; Sato, Yosuke; Fujii, Yukihiko


    The purpose of this paper is to report on the authors' advanced presurgical interactive virtual simulation technique using a 3D computer graphics model for microvascular decompression (MVD) surgery. The authors performed interactive virtual simulation prior to surgery in 26 patients with trigeminal neuralgia or hemifacial spasm. The 3D computer graphics models for interactive virtual simulation were composed of the brainstem, cerebellum, cranial nerves, vessels, and skull individually created by the image analysis, including segmentation, surface rendering, and data fusion for data collected by 3-T MRI and 64-row multidetector CT systems. Interactive virtual simulation was performed by employing novel computer-aided design software with manipulation of a haptic device to imitate the surgical procedures of bone drilling and retraction of the cerebellum. The findings were compared with intraoperative findings. In all patients, interactive virtual simulation provided detailed and realistic surgical perspectives, of sufficient quality, representing the lateral suboccipital route. The causes of trigeminal neuralgia or hemifacial spasm determined by observing 3D computer graphics models were concordant with those identified intraoperatively in 25 (96%) of 26 patients, which was a significantly higher rate than the 73% concordance rate (concordance in 19 of 26 patients) obtained by review of 2D images only (p computer graphics model provided a realistic environment for performing virtual simulations prior to MVD surgery and enabled us to ascertain complex microsurgical anatomy.

  16. Interactive Learning Environment: Web-based Virtual Hydrological Simulation System using Augmented and Immersive Reality (United States)

    Demir, I.


    Recent developments in internet technologies make it possible to manage and visualize large data on the web. Novel visualization techniques and interactive user interfaces allow users to create realistic environments, and interact with data to gain insight from simulations and environmental observations. The hydrological simulation system is a web-based 3D interactive learning environment for teaching hydrological processes and concepts. The simulation systems provides a visually striking platform with realistic terrain information, and water simulation. Students can create or load predefined scenarios, control environmental parameters, and evaluate environmental mitigation alternatives. The web-based simulation system provides an environment for students to learn about the hydrological processes (e.g. flooding and flood damage), and effects of development and human activity in the floodplain. The system utilizes latest web technologies and graphics processing unit (GPU) for water simulation and object collisions on the terrain. Users can access the system in three visualization modes including virtual reality, augmented reality, and immersive reality using heads-up display. The system provides various scenarios customized to fit the age and education level of various users. This presentation provides an overview of the web-based flood simulation system, and demonstrates the capabilities of the system for various visualization and interaction modes.

  17. Estimating and Measuring Application Latency of Typical Distributed Interactive Simulation (DIS)-Based Simulation Architecture (United States)


    model developed by Hodson 8 (2009), which characterizes the performance of distributed simulations in terms of temporal consistency. Summary In...inconsistency develops ). In a dynamically changing simulated environment, state data will have always “aged” by the time it is consumed, where “aged...Bottazzi & Salati, 1991). A variant of the model-view-controller ( MVC ) design pattern is typically used to create these types of multithreaded

  18. Fluid flow through reconstituted marine quartz sediments - an interacting lattice gas simulation (United States)

    Reed, Allen; Braithwaite, Edward; Gettrust, Joe; Pandey, Ras


    A porous sediment sample (cylinder of 5.9 mm diameter) is reconstituted in the laboratory using marine quartz sands from the Northern Gulf of Mexico. Digitized computed tomography images of sub-sample (cylinder of 6.5 mm diameter), removed from different regions of the laboratory sample, provide the porous matrix for an interacting lattice gas simulation. A cubic lattice of size 100^3 is used to represent the sediment matrix of the order of 64 mm^3. Different regions of the reconstituted sample are represented by corresponding porous matrices, each with a unique pore distribution. Mobile particles, the constituents of an interacting lattice gas, are used to model the fluid, which flows through the porous media from a source at the bottom to a sink at the top. Fluid particles are driven by their concentration gradient and an external pressure bias against gravity. Variations of the root mean square displacement of each particle (tracer) and that of their center of mass with the time steps, mass transfer and flux are examined as a function of the external pressure bias. Transport properties, including the response of the fluid flux to pressure bias, will be presented.

  19. Molecular dynamics simulations of membrane proteins and their interactions: from nanoscale to mesoscale. (United States)

    Chavent, Matthieu; Duncan, Anna L; Sansom, Mark Sp


    Molecular dynamics simulations provide a computational tool to probe membrane proteins and systems at length scales ranging from nanometers to close to a micrometer, and on microsecond timescales. All atom and coarse-grained simulations may be used to explore in detail the interactions of membrane proteins and specific lipids, yielding predictions of lipid binding sites in good agreement with available structural data. Building on the success of protein-lipid interaction simulations, larger scale simulations reveal crowding and clustering of proteins, resulting in slow and anomalous diffusional dynamics, within realistic models of cell membranes. Current methods allow near atomic resolution simulations of small membrane organelles, and of enveloped viruses to be performed, revealing key aspects of their structure and functionally important dynamics. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  20. NeuReal: an interactive simulation system for implementing artificial dendrites and large hybrid networks. (United States)

    Hughes, Stuart W; Lorincz, Magor; Cope, David W; Crunelli, Vincenzo


    The dynamic clamp is a technique which allows the introduction of artificial conductances into living cells. Up to now, this technique has been mainly used to add small numbers of 'virtual' ion channels to real cells or to construct small hybrid neuronal circuits. In this paper we describe a prototype computer system, NeuReal, that extends the dynamic clamp technique to include (i) the attachment of artificial dendritic structures consisting of multiple compartments and (ii) the construction of large hybrid networks comprising several hundred biophysically realistic modelled neurons. NeuReal is a fully interactive system that runs on Windows XP, is written in a combination of C++ and assembler, and uses the Microsoft DirectX application programming interface (API) to achieve high-performance graphics. By using the sampling hardware-based representation of membrane potential at all stages of computation and by employing simple look-up tables, NeuReal can simulate over 1000 independent Hodgkin and Huxley type conductances in real-time on a modern personal computer (PC). In addition, whilst not being a hard real-time system, NeuReal still offers reliable performance and tolerable jitter levels up to an update rate of 50kHz. A key feature of NeuReal is that rather than being a simple dedicated dynamic clamp, it operates as a fast simulation system within which neurons can be specified as either real or simulated. We demonstrate the power of NeuReal with several example experiments and argue that it provides an effective tool for examining various aspects of neuronal function.

  1. Examining the impact of high and medium fidelity simulation experiences on nursing students' knowledge acquisition. (United States)

    Levett-Jones, Tracy; Lapkin, Samuel; Hoffman, Kerry; Arthur, Carol; Roche, Jan


    This paper describes a study that measured and compared knowledge acquisition in nursing students exposed to medium or high fidelity human patient simulation manikins. In Australia and internationally the use of simulated learning environments has escalated. Simulation requires a significant investment of time and money and in a period of economic rationalisation this investment must be justified. Assessment of knowledge acquisition with multiple choice questions is the most common approach used to determine the effectiveness of simulation experiences. This study was conducted in an Australian school of nursing; 84 third year nursing students participated. A quasi-experimental design was used to evaluate the effect of the level of manikin fidelity on knowledge acquisition. Data were collected at three points in time: prior to the simulation, immediately following and two weeks later. Differences in mean scores between the control (medium fidelity) and experimental (high fidelity) groups for Tests 1, 2 and 3 were calculated using independent t tests and were not statistically significant. Analysis of covariance (ANCOVA) was conducted to determine whether changes in knowledge scores occurred over time and, while an improvement in scores was observed, it was not statistically significant. The results of this study raise questions about the value of investing in expensive simulation modalities when the increased costs associated with high fidelity manikins may not be justified by a concomitant increase learning outcomes. This study also suggests that multiple choice questions may not be the most appropriate measure of simulation effectiveness. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Pressure, relaxation volume, and elastic interactions in charged simulation cells (United States)

    Bruneval, Fabien; Varvenne, Céline; Crocombette, Jean-Paul; Clouet, Emmanuel


    The ab initio calculation of charged supercells within density-functional theory is a necessary step to access several important properties of matter. The relaxation volume of charged point defects or the partial molar volume of ions in solution are two such examples. However, the total energy and therefore the pressure of charged systems is not uniquely defined when periodic boundary conditions are employed. This problem is tightly related to the origin of the electrostatic potential in periodic systems. This effect can be easily observed by modifying the electrostatic convention or modifying the local ionic potential details. We propose an approach to uniquely define the pressures in charged supercells with the use of the absolute deformation potentials. Only with such a definition could the ab initio calculations provide meaningful values for the relaxation volumes and for the elastic interactions for charged defects in semiconductors or ions in solution. The proposed scheme allows one to calculate sensible data even when charge neutrality is not enforced, thus going beyond the classical force-field-based approaches.

  3. Water interaction with laboratory-simulated fossil fuel combustion particles. (United States)

    Popovicheva, O B; Kireeva, E D; Shonija, N K; Khokhlova, T D


    To clarify the impact of fossil fuel combustion particles' composition on their capacity to take up water, we apply a laboratory approach in which the method of deposition of compounds, identified in the particulate coverage of diesel and aircraft engine soot particles, is developed. It is found that near-monolayer organic/inorganic coverage of the soot particles may be represented by three groups of fossil fuel combustion-derived particulate matter with respect to their Hansh's coefficients related to hydrophilic properties. Water adsorption measurements show that nonpolar organics (aliphatic and aromatic hydrocarbons) lead to hydrophobization of the soot surface. Acidic properties of organic compounds such as those of oxidized PAHs, ethers, ketones, aromatic, and aliphatic acids are related to higher water uptake, whereas inorganic acids and ionic compounds such as salts of organic acids are shown to be responsible for soot hydrophilization. This finding allows us to quantify the role of the chemical identity of soot surface compounds in water uptake and the water interaction with fossil fuel combustion particles in the humid atmosphere.

  4. Numerical simulation of wave interactions during sudden stratospheric warming (United States)

    Gavrilov, N. M.; Koval, A. V.; Pogoreltsev, A. I.; Savenkova, E. N.


    Parameterizations of normal atmospheric modes (NAMs) and orographic gravity waves (OGWs) are implemented into the mechanistic general circulation model of the middle and upper atmosphere (MUA). Numerical experiments of sudden stratospheric warming (SSW) events are performed for climatological conditions typical for January and February using meteorological reanalysis data from the UK MET Office in the MUA model averaged over the years 1992-2011 with the easterly phase of quasi-biennial oscillation (QBO). The simulation shows that an increase in the OGW amplitudes occurs at altitudes higher than 30 km in the Northern Hemisphere after SSW. The OGW amplitudes have maximums at altitudes of about 50 km over the North American and European mountain systems before and during SSW, as well as over the Himalayas after SSW. At high latitudes of the Northern Hemisphere, significant (up to 50-70%) variations in the amplitudes of stationary planetary waves (SPWs) are observed during and after the SSW. Westward travelling NAMs have local amplitude maximums not only in the Northern Hemisphere, but also in the Southern Hemisphere, where there are waveguides for the propagation of these modes. Calculated variations of SPW and NAM amplitudes correspond to changes in the mean temperature and wind fields, as well as the Eliassen-Palm flux and atmospheric refractive index for the planetary waves, during SSW. Including OGW thermal and dynamical effects leads to an increase in amplitude (by 30-70%) of almost all SPWs before and during SSW and to a decrease (up to 20-100%) after the SSW at middle and high latitudes of the Northern Hemisphere.

  5. VASA: Interactive Computational Steering of Large Asynchronous Simulation Pipelines for Societal Infrastructure. (United States)

    Ko, Sungahn; Zhao, Jieqiong; Xia, Jing; Afzal, Shehzad; Wang, Xiaoyu; Abram, Greg; Elmqvist, Niklas; Kne, Len; Van Riper, David; Gaither, Kelly; Kennedy, Shaun; Tolone, William; Ribarsky, William; Ebert, David S


    We present VASA, a visual analytics platform consisting of a desktop application, a component model, and a suite of distributed simulation components for modeling the impact of societal threats such as weather, food contamination, and traffic on critical infrastructure such as supply chains, road networks, and power grids. Each component encapsulates a high-fidelity simulation model that together form an asynchronous simulation pipeline: a system of systems of individual simulations with a common data and parameter exchange format. At the heart of VASA is the Workbench, a visual analytics application providing three distinct features: (1) low-fidelity approximations of the distributed simulation components using local simulation proxies to enable analysts to interactively configure a simulation run; (2) computational steering mechanisms to manage the execution of individual simulation components; and (3) spatiotemporal and interactive methods to explore the combined results of a simulation run. We showcase the utility of the platform using examples involving supply chains during a hurricane as well as food contamination in a fast food restaurant chain.

  6. A novel approach to simulate gene-environment interactions in complex diseases

    Directory of Open Access Journals (Sweden)

    Nicodemi Mario


    Full Text Available Abstract Background Complex diseases are multifactorial traits caused by both genetic and environmental factors. They represent the major part of human diseases and include those with largest prevalence and mortality (cancer, heart disease, obesity, etc.. Despite a large amount of information that has been collected about both genetic and environmental risk factors, there are few examples of studies on their interactions in epidemiological literature. One reason can be the incomplete knowledge of the power of statistical methods designed to search for risk factors and their interactions in these data sets. An improvement in this direction would lead to a better understanding and description of gene-environment interactions. To this aim, a possible strategy is to challenge the different statistical methods against data sets where the underlying phenomenon is completely known and fully controllable, for example simulated ones. Results We present a mathematical approach that models gene-environment interactions. By this method it is possible to generate simulated populations having gene-environment interactions of any form, involving any number of genetic and environmental factors and also allowing non-linear interactions as epistasis. In particular, we implemented a simple version of this model in a Gene-Environment iNteraction Simulator (GENS, a tool designed to simulate case-control data sets where a one gene-one environment interaction influences the disease risk. The main aim has been to allow the input of population characteristics by using standard epidemiological measures and to implement constraints to make the simulator behaviour biologically meaningful. Conclusions By the multi-logistic model implemented in GENS it is possible to simulate case-control samples of complex disease where gene-environment interactions influence the disease risk. The user has full control of the main characteristics of the simulated population and a Monte

  7. Aggregation in colloidal suspensions: evaluation of the role of hydrodynamic interactions by means of numerical simulations. (United States)

    Tomilov, A; Videcoq, A; Cerbelaud, M; Piechowiak, M A; Chartier, T; Ala-Nissila, T; Bochicchio, D; Ferrando, R


    Numerical simulations constitute a precious tool for understanding the role of key parameters influencing the colloidal arrangement in suspensions, which is crucial for many applications. The present paper investigates numerically the role of hydrodynamic interactions on the aggregation processes in colloidal suspensions. Three simulation techniques are used: Brownian dynamics without hydrodynamic interactions, Brownian dynamics including some of the hydrodynamic interactions, using the Yamakawa-Rotne-Prager tensor, and stochastic rotation dynamics coupled with molecular dynamics. A system of monodisperse colloids strongly interacting through a generalized Lennard-Jones potential is studied for a colloid volume fraction ranging from 2.5 to 20%. Interestingly, effects of the hydrodynamic interactions are shown in the details of the aggregation processes. It is observed that the hydrodynamic interactions slow down the aggregation kinetics in the initial nucleation stage, while they speed up the next cluster coalescence stage. It is shown that the latter is due to an enhanced cluster diffusion in the simulations including hydrodynamic interactions. The higher the colloid volume fraction, the more pronounced the effects on the aggregation kinetics. It is also observed that hydrodynamic interactions slow down the reorganization kinetics. It turns out that the Brownian dynamics technique using the Yamakawa-Rotne-Prager tensor tends to overestimate the effects on cluster diffusion and cluster reorganization, even if it can be a method of choice for very dilute suspensions.

  8. Randomized trial to examine procedure-to-procedure transfer in laparoscopic simulator training

    DEFF Research Database (Denmark)

    Bjerrum, F; Sorensen, J L; Konge, L


    -centre educational superiority trial. Surgical novices practised basic skills on a laparoscopic virtual reality simulator. On reaching proficiency, participants were randomized to proficiency-based training. The intervention group practised two procedures on the simulator (appendicectomy followed by salpingectomy......BACKGROUND: Laparoscopic simulation has become a standard component of surgical training, but there is limited knowledge regarding skills transfer between procedural tasks. The objective was to investigate the specificity of procedural simulator training. METHODS: This was randomized single......), whereas the control group trained on only one procedure (salpingectomy). The main outcomes were number of repetitions and time to proficiency for the second procedure. RESULTS: Ninety-six participants were randomized, of whom 74 per cent were women, with a median age of 26 years. The intervention group...

  9. A simulation infrastructure for examining the performance of resilience strategies at scale.

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Kurt Brian; Levy, Scott N.; Bridges, Patrick G.


    Fault-tolerance is a major challenge for many current and future extreme-scale systems, with many studies showing it to be the key limiter to application scalability. While there are a number of studies investigating the performance of various resilience mechanisms, these are typically limited to scales orders of magnitude smaller than expected for next-generation systems and simple benchmark problems. In this paper we show how, with very minor changes, a previously published and validated simulation framework for investigating appli- cation performance of OS noise can be used to simulate the overheads of various resilience mechanisms at scale. Using this framework, we compare the failure-free performance of this simulator against an analytic model to validate its performance and demonstrate its ability to simulate the performance of two popular rollback recovery methods on traces from real

  10. Comparison of sea ice simulations with interactive and monthly averaged forcing models (United States)

    Wu, Xingren; Simmonds, Ian; Budd, W. F.


    A dynamic-thermodynamic sea ice model is developed and coupled with the "21 wave 9 level" Melbourne University general circulation model to simulate the seasonal cycle of the global sea ice distribution. We have run the coupled system and obtained a creditable seasonal simulation of global sea ice. When monthly averaged atmospheric data (taken from the mean of the coupled run) are used to force the sea ice model, the seasonal cycle of sea ice extent (to the outer ice edge) is quite similar to that simulated in the interactive run. However, the actual sea ice covered area (i.e., excluding leads) differs considerably between the two simulations. Sea ice is more compact in the monthly averaged forced run than in the interactive run throughout the year in both hemispheres. The sea ice thickness distribution also differs between the two runs. In general, the sea ice is more open and thicker in the seasonal ice zone of the two polar regions for the interactive coupled case than for the mean forcing. We have also run the model forced with daily atmospheric data and the simulated sea ice distribution differs significantly from both the interactive model and the monthly averaged forcing results. These differences highlight the dangers of undertaking studies with sea ice models forced with prescribed atmospheric conditions rather than using a fully interactive atmosphere-sea ice system.

  11. Interaction of Tenebrio Molitor Antifreeze Protein with Ice Crystal: Insights from Molecular Dynamics Simulations. (United States)

    Ramya, L; Ramakrishnan, Vigneshwar


    Antifreeze proteins (AFP) observed in cold-adapting organisms bind to ice crystals and prevent further ice growth. However, the molecular mechanism of AFP-ice binding and AFP-inhibited ice growth remains unclear. Here we report the interaction of the insect antifreeze protein (Tenebrio molitor, TmAFP) with ice crystal by molecular dynamics simulation studies. Two sets of simulations were carried out at 263 K by placing the protein near the primary prism plane (PP) and basal plane (BL) of the ice crystal. To delineate the effect of temperatures, both the PP and BL simulations were carried out at 253 K as well. The analyses revealed that the protein interacts strongly with the ice crystal in BL simulation than in PP simulation both at 263 K and 253 K. Further, it was observed that the interactions are primarily mediated through the interface waters. We also observed that as the temperature decreases, the interaction between the protein and the ice increases which can be attributed to the decreased flexibility and the increased structuring of the protein at low temperature. In essence, our study has shed light on the interaction mechanism between the TmAFP antifreeze protein and the ice crystal. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Full Enzyme Complex Simulation: Interactions in Human Pyruvate Dehydrogenase Complex. (United States)

    Hezaveh, Samira; Zeng, An-Ping; Jandt, Uwe


    The pyruvate dehydrogenase complex (PDC) is a large macromolecular machine consisting of dozens of interacting enzymes that are connected and regulated by highly flexible domains, also called swinging arms. The overall structure and function of these domains and how they organize the complex function have not been elucidated in detail to date. This lack of structural and dynamic understanding is frequently observed in multidomain enzymatic complexes. Here we present the first full and dynamic structural model of full human PDC (hPDC), including binding of the linking arms to the surrounding E1 and E3 enzymes via their binding domains with variable stoichiometries. All of the linking domains were modeled at atomistic and coarse-grained levels, and the latter was parametrized to reproduce the same properties of those from the atomistic model. The radii of gyration of the wild-type full complex and functional trimeric subunits were in agreement with available experimental data. Furthermore, the E1 and E3 population effect on the overall structure of the full complex was studied. The results indicated that decreasing the number of E1s increases the flexibility of the now nonoccupied arms. Furthermore, their flexibility depends on the presence of other E1s and E3s in the vicinity, even if they are associated with other arms. As one consequence, the radius of gyration decreases with decreasing number of E1s. This effect also provides an indication of the optimal configuration of E1 and E3 on the basis of the assumption that a certain stability of the enymatic cloud is necessary to avoid free metabolic diffusion of intermediates (metabolic channeling). Our approach and results open a window for future enzyme engineering in a more effective way by evaluating the effect of different linker arm lengths, flexibilities, and combinations of mutations on the activity of other complex enzymes that involve flexible domains, including for example processive enzymes.

  13. Measurement and simulation of high voltage-wake interactions

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, D.A.; Olsen, D.; Burke, W.J.; Ginet, G. [AF Phillips Lab., Hanscom AFB, MA (United States); Gough, P. [Univ. of Sussex (United Kingdom); Huang, C. [Boston Coll., Chestnut Hills, MA (United States); James, H.G. [Canadian Communication Centre, Ottawa, Ontario (Canada)


    Oedipus C was a tethered mother-son payload with a 50 kHz to 8.0 Mhz stepped frequency transmitter on the forward payload and a HF receiver on the aft payload. In the course of the upleg of the flight the tether was deployed to a distance of approximately 1 km. At apogee the tether was cut. As part of the compliment of environmental sensors, multiangular electrostatic analyzers were flown on both the forward and aft payloads. These detectors compiled 10, 32 point electron spectra/second over the energy range from 20 eV to 20 keV and in 8 angular zones defining a detection fan of 1,440{degree} by 100{degree}. The HF transmitter was normally swept through 165 frequency steps every .5 seconds. The stepping of the electrostatic analyzer was synchronized to the stepping of the transmitter such that the analyzer measured at a fixed frequency at each energy step. The output pulses of the electrostatic analyzers were also processed by an on-board particle correlator that measured bunching in the electron flux produced by coherent wave-particle interactions. Throughout the flight the analyzer in the forward payload measured large increases in the electron flux at energies up to several keV and over a wide angular range whenever the transmitter was emitting at approximately the local electron gyrofrequency. Similar effects were seen on the aft payload for separation up to several hundred meters. In addition, weaker electron flux enhancements were also seen at sub-harmonics of the gyrofrequency at low altitudes. The correlator measured clear Mhz modulation of the electrons at harmonics of the gyrofrequency. The data indicate strong heating of the local plasma due to the HF wave injection.

  14. Examining Residents' Strategic Mindfulness During Self-Regulated Learning of a Simulated Procedural Skill. (United States)

    Brydges, Ryan; Hatala, Rose; Mylopoulos, Maria


    Simulation-based training is currently embedded in most health professions education curricula. Without evidence for how trainees think about their simulation-based learning, some training techniques may not support trainees' learning strategies. This study explored how residents think about and self-regulate learning during a lumbar puncture (LP) training session using a simulator. In 2010, 20 of 45 postgraduate year 1 internal medicine residents attended a mandatory procedural skills training boot camp. Independently, residents practiced the entire LP skill on a part-task trainer using a clinical LP tray and proper sterile technique. We interviewed participants regarding how they thought about and monitored their learning processes, and then we conducted a thematic analysis of the interview data. The analysis suggested that participants considered what they could and could not learn from the simulator; they developed their self-confidence by familiarizing themselves with the LP equipment and repeating the LP algorithmic steps. Participants articulated an idiosyncratic model of learning they used to interpret the challenges and successes they experienced. Participants reported focusing on obtaining cerebrospinal fluid and memorizing the "routine" version of the LP procedure. They did not report much thinking about their learning strategies (eg, self-questioning). During simulation-based training, residents described assigning greater weight to achieving procedural outcomes and tended to think that the simulated task provided them with routine, generalizable skills. Over this typical 1-hour session, trainees did not appear to consider their strategic mindfulness (ie, awareness and use of learning strategies).

  15. Optical Storage Interactive Simulator ( oasis ): An Interactive Tool for the Analysis of Page-Oriented Optical Memories (United States)

    Betzos, George A.; Porter, Michael S.; Hutton, John F.; Mitkas, Pericles A.


    Page-oriented optical memories combine high capacity with massive data-transfer rates and could provide the next generation of secondary storage systems. Several technological barriers need to be overcome before these memories become commercial products. One is the need for efficient interfaces to electronic computers. To assist in the analysis of all issues pertaining to such an interface, we have developed the optical storage interactive simulator ( oasis ), an interactive software tool. oasis can simulate data-encoding schemes, noise sources present in a particular memory system, and data-recovery mechanisms. Bit-error rates and other useful statistics can also be measured. The user has the option of studying the effects of individual error sources to the system output or of applying several of them in any order dictated by the system architecture. This multifaceted analysis will assist the user in evaluating the effectiveness of a particular error-correcting code and choosing the right one for the system.

  16. Optical Storage Interactive Simulator (oasis): An Interactive Tool for the Analysis of Page-Oriented Optical Memories. (United States)

    Betzos, G A; Porter, M S; Hutton, J F; Mitkas, P A


    Page-oriented optical memories combine high capacity with massive data-transfer rates and could provide the next generation of secondary storage systems. Several technological barriers need to be overcome before these memories become commercial products. One is the need for efficient interfaces to electronic computers. To assist in the analysis of all issues pertaining to such an interface, we have developed the optical storage interactive simulator (oasis), an interactive software tool. oasis can simulate data-encoding schemes, noise sources present in a particular memory system, and data-recovery mechanisms. Bit-error rates and other useful statistics can also be measured. The user has the option of studying the effects of individual error sources to the system output or of applying several of them in any order dictated by the system architecture. This multifaceted analysis will assist the user in evaluating the effectiveness of a particular error-correcting code and choosing the right one for the system.

  17. Quality Standards Matter: A Comparative Case Study Examining Interactive Writing in the Preschool Setting (United States)

    Hall, Anna H.


    Interactive writing is a research-based early literacy strategy that has been found effective at increasing young children's oral language skills, alphabet knowledge, phonemic awareness, concepts of print, and early writing skills. This paper reports on a case study which explored the feasibility and fidelity of implementing interactive writing in…

  18. Social anhedonia and affiliation: examining behavior and subjective reactions within a social interaction. (United States)

    Llerena, Katiah; Park, Stephanie G; Couture, Shannon M; Blanchard, Jack J


    Social anhedonia is a promising indicator for the vulnerability towards developing schizophrenia-spectrum disorders and is an important determinant of the social impairment associated with these disorders. It is unknown if social anhedonia is associated with true deficits in experiential reactions or if lower social functioning in social anhedonia reflects behavioral deficits in social skill or initiation of social contact. Using a novel social interaction task, the current study compared controls (n=60) to individuals elevated on social anhedonia (n=49) on observer-rated social skill and facial affect and participant self-reports of their experiential reactions to an affiliative interaction. Compared to the control group, the social anhedonia group was rated as behaviorally less affiliative and less socially skilled during the affiliative interaction. In response to the social interaction, the social anhedonia group reported less change in positive affect, less willingness to engage in future social interactions with the interaction partner, and less positive reactions toward the interaction partner compared to controls. There were no group differences in facial displays of emotion. Using a standardized affiliative stimulus, it was demonstrated that individuals high in social anhedonia have alterations in both their social skill and in their self-reported experiential reactions during a social interaction. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  19. Modeling and Simulation of Process-Machine Interaction in Grinding of Cemented Carbide Indexable Inserts

    Directory of Open Access Journals (Sweden)

    Wei Feng


    Full Text Available Interaction of process and machine in grinding of hard and brittle materials such as cemented carbide may cause dynamic instability of the machining process resulting in machining errors and a decrease in productivity. Commonly, the process and machine tools were dealt with separately, which does not take into consideration the mutual interaction between the two subsystems and thus cannot represent the real cutting operations. This paper proposes a method of modeling and simulation to understand well the process-machine interaction in grinding process of cemented carbide indexable inserts. First, a virtual grinding wheel model is built by considering the random nature of abrasive grains and a kinematic-geometrical simulation is adopted to describe the grinding process. Then, a wheel-spindle model is simulated by means of the finite element method to represent the machine structure. The characteristic equation of the closed-loop dynamic grinding system is derived to provide a mathematic description of the process-machine interaction. Furthermore, a coupling simulation of grinding wheel-spindle deformations and grinding process force by combining both the process and machine model is developed to investigate the interaction between process and machine. This paper provides an integrated grinding model combining the machine and process models, which can be used to predict process-machine interactions in grinding process.

  20. De la simulation multi-agents à la simulation multi-niveaux. Pour une réification des interactions.


    Picault, Sébastien


    In this Habilitation Thesis, I present my research activity in the field of multiagent simulation within the SMAC team (LIFL, Université Lille 1), since the beginning of my career of teacher and researcher in 2002. My work focuses on the design and implementation of methods and tools aimed at facilitating the modeling of large-scale complex systems. Therefore, I developped with my colleagues an " interaction-oriented " approach, characterized by the unification of several concepts used in the...

  1. Resolving solvophobic interactions inferred from experimental solvation free energies and evaluated from molecular simulations (United States)

    Barnett, J. Wesley; Bhutta, Amna; Bierbrier, Sarah C.; da Silva Moura, Natalia; Ashbaugh, Henry S.


    Ben-Naim estimated the solvent-mediated interaction between methanes based on experimental solvation free energy differences between chemically similar hydrocarbons. Interactions were predicted to be strongest in water, dominated by characteristic entropic gains. We use molecular simulations in combination with an empirical interpolation procedure that bridges interactions from outside methane's excluded volume down to overlap to test Ben-Naim's estimates. While Ben-Naim's approach captures many distinctive trends, the alchemical differences between methane and a methyl unit play a non-trivial role on the predicted association strength and the sign of enthalpic and entropic components of the interaction free energy in water and ethanol.

  2. A Guide for Developing Human-Robot Interaction Experiments in the Robotic Interactive Visualization and Experimentation Technology (RIVET) Simulation (United States)


    Portugal): INSTICC Press; c2008. p. 323–328. Her MG, Hsu KS. Design and analysis of haptic direct drive robot for virtual reality . Journal of...development for the nonprogrammer with example TorqueScript files and step-by-step instructions to develop the virtual environment. Additional...interaction, RIVET, simulation 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18. NUMBER OF PAGES 162 19a. NAME OF

  3. Interactive Ozone and Methane Chemistry in GISS-E2 Historical and Future Climate Simulations (United States)

    Shindell, D. T.; Pechony, O.; Voulgarakis, A.; Faluvegi, G.; Nazarenko. L.; Lamarque, J.-F.; Bowman, K.; Milly, G.; Kovari, B.; Ruedy, R.; hide


    The new generation GISS climate model includes fully interactive chemistry related to ozone in historical and future simulations, and interactive methane in future simulations. Evaluation of ozone, its tropospheric precursors, and methane shows that the model captures much of the largescale spatial structure seen in recent observations. While the model is much improved compared with the previous chemistry-climate model, especially for ozone seasonality in the stratosphere, there is still slightly too rapid stratospheric circulation, too little stratosphere-to-troposphere ozone flux in the Southern Hemisphere and an Antarctic ozone hole that is too large and persists too long. Quantitative metrics of spatial and temporal correlations with satellite datasets as well as spatial autocorrelation to examine transport and mixing are presented to document improvements in model skill and provide a benchmark for future evaluations. The difference in radiative forcing (RF) calculated using modeled tropospheric ozone versus tropospheric ozone observed by TES is only 0.016W/sq. m. Historical 20th Century simulations show a steady increase in whole atmosphere ozone RF through 1970 after which there is a decrease through 2000 due to stratospheric ozone depletion. Ozone forcing increases throughout the 21st century under RCP8.5 owing to a projected recovery of stratospheric ozone depletion and increases in methane, but decreases under RCP4.5 and 2.6 due to reductions in emissions of other ozone precursors. RF from methane is 0.05 to 0.18W/ sq. m higher in our model calculations than in the RCP RF estimates. The surface temperature response to ozone through 1970 follows the increase in forcing due to tropospheric ozone. After that time, surface temperatures decrease as ozone RF declines due to stratospheric depletion. The stratospheric ozone depletion also induces substantial changes in surface winds and the Southern Ocean circulation, which may play a role in a slightly stronger

  4. Interactive ozone and methane chemistry in GISS-E2 historical and future climate simulations

    Directory of Open Access Journals (Sweden)

    D. T. Shindell


    Full Text Available The new generation GISS climate model includes fully interactive chemistry related to ozone in historical and future simulations, and interactive methane in future simulations. Evaluation of ozone, its tropospheric precursors, and methane shows that the model captures much of the large-scale spatial structure seen in recent observations. While the model is much improved compared with the previous chemistry-climate model, especially for ozone seasonality in the stratosphere, there is still slightly too rapid stratospheric circulation, too little stratosphere-to-troposphere ozone flux in the Southern Hemisphere and an Antarctic ozone hole that is too large and persists too long. Quantitative metrics of spatial and temporal correlations with satellite datasets as well as spatial autocorrelation to examine transport and mixing are presented to document improvements in model skill and provide a benchmark for future evaluations. The difference in radiative forcing (RF calculated using modeled tropospheric ozone versus tropospheric ozone observed by TES is only 0.016 W m−2. Historical 20th Century simulations show a steady increase in whole atmosphere ozone RF through 1970 after which there is a decrease through 2000 due to stratospheric ozone depletion. Ozone forcing increases throughout the 21st century under RCP8.5 owing to a projected recovery of stratospheric ozone depletion and increases in methane, but decreases under RCP4.5 and 2.6 due to reductions in emissions of other ozone precursors. RF from methane is 0.05 to 0.18 W m−2 higher in our model calculations than in the RCP RF estimates. The surface temperature response to ozone through 1970 follows the increase in forcing due to tropospheric ozone. After that time, surface temperatures decrease as ozone RF declines due to stratospheric depletion. The stratospheric ozone depletion also induces substantial changes in surface winds and the Southern Ocean circulation, which may play a role in

  5. Suitability of oyster restoration sites along the Louisiana coast: Examining site and stock × site interaction (United States)

    Schwarting Miller, Lindsay; La Peyre, Jerome F.; LaPeyre, Megan K.


    Recognition of the global loss of subtidal oyster reefs has led to a rise in reef restoration efforts, including in the Gulf of Mexico. Created reef success depends entirely on selecting a location that supports long-term oyster growth and survival, including the recruitment and survival of on-reef oysters. Significant changes in estuarine salinity through management of freshwater inflows and through changed precipitation patterns may significantly impact the locations of optimal oyster restoration sites. These rapid shifts in conditions necessitate a need to better understand both impacts to on-reef oyster growth and population development, and variation in oyster stock performance. Oyster growth, mortality, condition, and disease prevalence were examined in three different stocks of oysters located in protected cages, as well as oyster recruitment and mortality on experimental reef units in three different locations representing a salinity gradient, along the Louisiana Gulf coast in 2011 and 2012. Over a 2-y period, the high-salinity site had highest oyster growth rate in protected cages but demonstrated the least likelihood for reef development based on on-reef oyster population failure, likely because of predation-related mortality (high recruitment and 100% mortality). In contrast, the midsalinity site with moderate oyster growth and on-reef recruitment and low mortality demonstrated a higher likelihood for reef development. The lowest salinity site exhibited extreme variability in all oyster responses between years because of extreme variation in environmental conditions during the study, indicating a low likelihood of long-term reef development. Whereas limited differences in stock performance between sites were found, the range of site environmental conditions tested was ultimately much lower than expected and may not have provided a wide enough range of conditions. In areas with limited, low recruitment, or rapidly changing environmental conditions

  6. Examining Passenger Flow Choke Points at Airports Using Discrete Event Simulation (United States)

    Brown, Jeremy R.; Madhavan, Poomima


    The movement of passengers through an airport quickly, safely, and efficiently is the main function of the various checkpoints (check-in, security. etc) found in airports. Human error combined with other breakdowns in the complex system of the airport can disrupt passenger flow through the airport leading to lengthy waiting times, missing luggage and missed flights. In this paper we present a model of passenger flow through an airport using discrete event simulation that will provide a closer look into the possible reasons for breakdowns and their implications for passenger flow. The simulation is based on data collected at Norfolk International Airport (ORF). The primary goal of this simulation is to present ways to optimize the work force to keep passenger flow smooth even during peak travel times and for emergency preparedness at ORF in case of adverse events. In this simulation we ran three different scenarios: real world, increased check-in stations, and multiple waiting lines. Increased check-in stations increased waiting time and instantaneous utilization. while the multiple waiting lines decreased both the waiting time and instantaneous utilization. This simulation was able to show how different changes affected the passenger flow through the airport.

  7. Simbuca, using a graphics card to simulate Coulomb interactions in a penning trap

    CERN Document Server

    Van Gorp, S; Friedag, P; De Leebeeck, V; Tandecki, M; Weinheimer, C; Breitenfeldt, M; Traykov, E; Severijn, N; Mader, J; Soti, G; Iitaka, T; Herlert, A; Wauters, F; Zakoucky, D; Kozlov, V; Roccia, S


    In almost all cases, N-body simulations are limited by the computation time available. Coulomb interaction calculations scale with O(N(2)) with N the number of particles. Approximation methods exist already to reduce the computation time to O(NlogN) although calculating the interaction still dominates the total simulation time. We present Simbuca, a simulation package for thousands of ions moving in a Penning trap which will be applied for the WITCH experiment. Simbuca uses the output of the Cunbody-1 library, which calculates the gravitational interaction between entities on a graphics card, and adapts it for Coulomb calculations. Furthermore the program incorporates three realistic buffer gas models, the possibility of importing realistic electric and magnetic fieldmaps and different order integrators with adaptive step size and error control. The software is released under the GNU General Public License and free for use. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.

  8. Characterization of the Interaction between Gallic Acid and Lysozyme by Molecular Dynamics Simulation and Optical Spectroscopy. (United States)

    Zhan, Minzhong; Guo, Ming; Jiang, Yanke; Wang, Xiaomeng


    The binding interaction between gallic acid (GA) and lysozyme (LYS) was investigated and compared by molecular dynamics (MD) simulation and spectral techniques. The results from spectroscopy indicate that GA binds to LYS to generate a static complex. The binding constants and thermodynamic parameters were calculated. MD simulation revealed that the main driving forces for GA binding to LYS are hydrogen bonding and hydrophobic interactions. The root-mean-square deviation verified that GA and LYS bind to form a stable complex, while the root-mean-square fluctuation results showed that the stability of the GA-LYS complex at 298 K was higher than that at 310 K. The calculated free binding energies from the molecular mechanics/Poisson-Boltzmann surface area method showed that van der Waals forces and electrostatic interactions are the predominant intermolecular forces. The MD simulation was consistent with the spectral experiments. This study provides a reference for future study of the pharmacological mechanism of GA.

  9. Mourning and Grief on Facebook: An Examination of Motivations for Interacting With the Deceased. (United States)

    Willis, Erin; Ferrucci, Patrick


    Facebook not only changed the way we communicate but also the way we mourn and express grief. The social networking site allows users to interact with deceased users' walls after death. This study utilized textual analysis to categorize Facebook posts ( N = 122) on 30 deceased users' walls according to uses and gratifications theory. Most posts were found to be motivated by entertainment, followed by integration and social interaction. Facebook users posted memories, condolences, and interacted with friends and family members in the deceased user's network. Implications and potential future research are discussed.

  10. Assessment of performance measures and learning curves for use of a virtual-reality ultrasound simulator in transvaginal ultrasound examination

    DEFF Research Database (Denmark)

    Madsen, M E; Konge, L; Nørgaard, L N


    -6), corresponding to an average of 219 min (range, 150-251 min) of training. The test/retest reliability was high, with an intraclass correlation coefficient of 0.93. CONCLUSIONS: Competence in the performance of gynecological ultrasound examination can be assessed in a valid and reliable way using virtual-reality......OBJECTIVE: To assess the validity and reliability of performance measures, develop credible performance standards and explore learning curves for a virtual-reality simulator designed for transvaginal gynecological ultrasound examination. METHODS: A group of 16 ultrasound novices, along with a group...... simulation. The novices' performance improved with practice and their learning curves plateaued at the level of expert performance, following between 3 and 4 h of simulator training....

  11. Model intestinal microflora in computer simulation : A simulation and modeling package for host-microflora interactions

    NARCIS (Netherlands)

    Wilkinson, Michael H.F.


    The ecology of the human intestinal microflora and its interaction with the host are poorly understood. Though more and more data are being acquired, in part using modern molecular methods, development of a quantitative theory has not kept pace with this increase in observing power. This is in part

  12. Impact of routine follow-up examinations on life expectancy in ovarian cancer patients: a simulation study.

    NARCIS (Netherlands)

    Geurts, S.M.E.; Vegt, F. de; Altena, A.M. van; Tjan-Heijnen, V.C.; Massuger, L.F.A.G.; Adang, E.M.M.; Dijck, J.A.A.M. van; Verbeek, A.L.M.


    OBJECTIVE: The clinical benefit of routine follow-up in patients treated for ovarian cancer is subject to debate. In this study, the magnitude of the potential survival benefit of routine examinations was evaluated by Markov modeling. METHODS: The clinical course of ovarian cancer was simulated

  13. Correlation of Simulation Examination to Written Test Scores for Advanced Cardiac Life Support Testing: Prospective Cohort Study

    Directory of Open Access Journals (Sweden)

    Suzanne L. Strom


    Full Text Available Introduction: Traditional Advanced Cardiac Life Support (ACLS courses are evaluated using written multiple-choice tests. High-fidelity simulation is a widely used adjunct to didactic content, and has been used in many specialties as a training resource as well as an evaluative tool. There are no data to our knowledge that compare simulation examination scores with written test scores for ACLS courses. Objective: To compare and correlate a novel high-fidelity simulation-based evaluation with traditional written testing for senior medical students in an ACLS course. Methods: We performed a prospective cohort study to determine the correlation between simulationbased evaluation and traditional written testing in a medical school simulation center. Students were tested on a standard acute coronary syndrome/ventricular fibrillation cardiac arrest scenario. Our primary outcome measure was correlation of exam results for 19 volunteer fourth-year medical students after a 32-hour ACLS-based Resuscitation Boot Camp course. Our secondary outcome was comparison of simulation-based vs. written outcome scores. Results: The composite average score on the written evaluation was substantially higher (93.6% than the simulation performance score (81.3%, absolute difference 12.3%, 95% CI [10.6-14.0%], p<0.00005. We found a statistically significant moderate correlation between simulation scenario test performance and traditional written testing (Pearson r=0.48, p=0.04, validating the new evaluation method. Conclusion: Simulation-based ACLS evaluation methods correlate with traditional written testing and demonstrate resuscitation knowledge and skills. Simulation may be a more discriminating and challenging testing method, as students scored higher on written evaluation methods compared to simulation.

  14. Interactive Pre-Simulation Strategies: Engaging Students in Experiential Learning from the Start

    Directory of Open Access Journals (Sweden)

    Beverly J. D. Bye


    Full Text Available Decrease in clinical nursing facilities created a need to develop supplemental real-life patient scenarios outside of the traditional nursing units. Over the past five years, there has been a dramatic increase in the number of simulation exercises integrated into the clinical and classroom aspect of nursing education. However, many students are not engaged and are not effectively participating in the simulation. Many students state they are perplexed and do not understand the purpose and roles of simulation, and often do not take it seriously. The challenge to nurse educators is to develop realistic goals and objectives with a variety of activities that occur prior to the actual simulation experience Debriefing is one of the most important aspects of the simulation activity, but if students are not participating, then the learning is not occurring. The key with simulation is to engage students through the use of various strategies that incorporate visual, auditory, tactile, and cognitive learning prior to the simulation experience. This study investigated the use of interactive pre-simulation strategies such as concept mapping, group discussion, teaching, and body mapping prior to the simulation experience. The focus of this research was on student success and knowledge acquisition. The most important overall goal is to engage students prior to the simulation experience in a safe, nonthreatening learning environment in order to allay students' fear of failure and ultimately increase knowledge, retention, and critical thinking. Results of the study have implications on the development and integration of innovative teaching pedagogies.

  15. Fear of missing a lesion: use of simulated breast models to decrease student anxiety when learning clinical breast examinations. (United States)

    Pugh, Carla M; Salud, Lawrence H


    Medical students experience a considerable amount of discomfort during their training. The purpose of the current study was to identify sources of student anxiety when learning clinical breast examinations (CBEs) and to evaluate the effects of simulated breast models on student comfort. Simulated breast models were introduced into the curriculum for 175 second-year medical students. Using surveys, students identified sources of anxiety and rated their comfort levels when learning CBE skills. "Fear of missing a lesion" and the "Intimate/personal nature of the exam" accounted for 73.8% of student anxiety when learning CBEs. In addition, there were significant improvements (P student comfort levels when using simulated breast models to learn CBE skills. We have identified 2 of the top causes of anxiety for second-year medical students learning CBE. In addition, we found simulated breast models to be effective in increasing student comfort levels when learning CBEs.

  16. Interactions between ether phospholipids and cholesterol as determined by scattering and molecular dynamics simulations. (United States)

    Pan, Jianjun; Cheng, Xiaolin; Heberle, Frederick A; Mostofian, Barmak; Kučerka, Norbert; Drazba, Paul; Katsaras, John


    Cholesterol and ether lipids are ubiquitous in mammalian cell membranes, and their interactions are crucial in ether lipid mediated cholesterol trafficking. We report on cholesterol's molecular interactions with ether lipids as determined using a combination of small-angle neutron and X-ray scattering, and all-atom molecular dynamics (MD) simulations. A scattering density profile model for an ether lipid bilayer was developed using MD simulations, which was then used to simultaneously fit the different experimental scattering data. From analysis of the data the various bilayer structural parameters were obtained. Surface area constrained MD simulations were also performed to reproduce the experimental data. This iterative analysis approach resulted in good agreement between the experimental and simulated form factors. The molecular interactions taking place between cholesterol and ether lipids were then determined from the validated MD simulations. We found that in ether membranes cholesterol primarily hydrogen bonds with the lipid headgroup phosphate oxygen, while in their ester membrane counterparts cholesterol hydrogen bonds with the backbone ester carbonyls. This different mode of interaction between ether lipids and cholesterol induces cholesterol to reside closer to the bilayer surface, dehydrating the headgroup's phosphate moiety. Moreover, the three-dimensional lipid chain spatial density distribution around cholesterol indicates anisotropic chain packing, causing cholesterol to tilt. These insights lend a better understanding of ether lipid-mediated cholesterol trafficking and the roles that the different lipid species have in determining the structural and dynamical properties of membrane associated biomolecules.

  17. Interactions between Ether Phospholipids and Cholesterol as Determined by Scattering and Molecular Dynamics Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Jianjun [ORNL; Cheng, Xiaolin [ORNL; Heberle, Frederick A [ORNL; Mostofian, Barmak [ORNL; Kucerka, Norbert [Canadian Neutron Beam Centre and Comelius University (Slovakia); Drazba, Paul [ORNL; Katsaras, John [ORNL


    Cholesterol and ether lipids are ubiquitous in mammalian cell membranes, and their interactions are crucial in ether lipid mediated cholesterol trafficking. We report on cholesterol s molecular interactions with ether lipids as determined using a combination of small-angle neutron and Xray scattering, and all-atom molecular dynamics (MD) simulations. A scattering density profile model for an ether lipid bilayer was developed using MD simulations, which was then used to simultaneously fit the different experimental scattering data. From analysis of the data the various bilayer structural parameters were obtained. Surface area constrained MD simulations were also performed to reproduce the experimental data. This iterative analysis approach resulted in good agreement between the experimental and simulated form factors. The molecular interactions taking place between cholesterol and ether lipids were then determined from the validated MD simulations. We found that in ether membranes cholesterol primarily hydrogen bonds with the lipid headgroup phosphate oxygen, while in their ester membrane counterparts cholesterol hydrogen bonds with the backbone ester carbonyls. This different mode of interaction between ether lipids and cholesterol induces cholesterol to reside closer to the bilayer surface, dehydrating the headgroup s phosphate moiety. Moreover, the three-dimensional lipid chain spatial density distribution around cholesterol indicates anisotropic chain packing, causing cholesterol to tilt. These insights lend a better understanding of ether lipid-mediated cholesterol trafficking and the roles that the different lipid species have in determining the structural and dynamical properties of membrane associated biomolecules.

  18. Lattice-Boltzmann simulation of laser interaction with weakly ionized helium plasmas. (United States)

    Li, Huayu; Ki, Hyungson


    This paper presents a lattice Boltzmann method for laser interaction with weakly ionized plasmas considering electron impact ionization and three-body recombination. To simulate with physical properties of plasmas, the authors' previous work on the rescaling of variables is employed and the electromagnetic fields are calculated from the Maxwell equations by using the finite-difference time-domain method. To calculate temperature fields, energy equations are derived separately from the Boltzmann equations. In this way, we attempt to solve the full governing equations for plasma dynamics. With the developed model, the continuous-wave CO2 laser interaction with helium is simulated successfully.

  19. A Novel FEM-Based Numerical Solver for Interactive Catheter Simulation in Virtual Catheterization

    Directory of Open Access Journals (Sweden)

    Shun Li


    Full Text Available Virtual reality-based simulators are very helpful for trainees to acquire the skills of manipulating catheters and guidewires during the vascular interventional surgeries. In the development of such a simulator, however, it is a great challenge to realistically model and simulate deformable catheters and guidewires in an interactive manner. We propose a novel method to simulate the motion of catheters or guidewires and their interactions with patients' vascular system. Our method is based on the principle of minimal total potential energy. We formulate the total potential energy in the vascular interventional circumstance by summing up the elastic energy deriving from the bending of the catheters or guidewires, the potential energy due to the deformation of vessel walls, and the work by the external forces. We propose a novel FEM-based approach to simulate the deformation of catheters and guidewires. The motion of catheters or the guidewires and their responses to every input from the interventionalist can be calculated globally. Experiments have been conducted to validate the feasibility of the proposed method, and the results demonstrate that our method can realistically simulate the complex behaviors of catheters and guidewires in an interactive manner.

  20. Interactions between proteins and poly(ethylene-glycol) investigated using molecular dynamics simulations (United States)

    Settanni, Giovanni; Zhou, Jiajia; Schmid, Friederike


    Poly(ethylene-glycol) (PEG) is a polymer used to coat therapeutic preparations, like drugs or drug nanocarriers, and improve their efficacy. This effect is probably due to a reduction of the interactions of the coated species with the host organism. Nevertheless, experiments show that PEGylated materials do interact with the surrounding biological milieu, and in particular with blood proteins. Here, we use atomistic molecular dynamics simulations to characterize the interactions between the polymer and several blood proteins. In these simulations, the proteins are immersed in a mixture of PEG and water molecules. We observe how PEG distributes around the protein surface and measure PEG-protein interactions in terms of preferential binding coefficients.

  1. Examining the Impact of a Domestic Violence Simulation on the Development of Empathy in Sociology Classes (United States)

    Latshaw, Beth A.


    Increasing empathy toward others is an unspoken goal of many sociology courses, but rarely do instructors measure changes in empathy throughout a semester. To address this gap in the literature, I use a combination of quantitative and qualitative data gathered before and after students from five sociology classes participated in a simulation on…

  2. Self-construal, affective valence of the encounter, and quality of social interactions: Within and cross-culture examination. (United States)

    Kafetsios, Konstantinos; Hess, Ursula; Nezlek, John B


    In two samples, one from Greece and another from Germany, we examined relationships between self-construal, emotional experience, and the quality of social interactions. In Greece, a more collectivistic culture, the negative affect people experienced in social interactions was more weakly related to the quality of social interactions for those higher in interdependent self-construal than it was for those lower in interdependent self-construal. In Germany, a more independent culture, a contrasting pattern was observed such that the positive affect people experienced in social interaction was more strongly related to the quality of social interactions for those higher in independent self-construal than it was for those lower in independent self-construal. These findings suggest that positive and negative affect in social encounters can have different effects for persons with independent and interdependent cultural orientations within different cultural settings.

  3. Cercignani-Lampis-Lord gas-surface interaction model: Comparisons between theory and simulation (United States)

    Woronowicz, M. S.; Rault, D. F. G.


    The article presents a study on the phenomenon of gas surface interaction using Cercigni Lampis Lord gas surface interaction model. The C-L model is incorporated into a free molecule theory to create complex expressions describing lift and drag coefficients. The experiment was done on flow over a single sided plate with freestream speed and direct simulation Monte Carlo (DSMC) estimates were studied for lift and drag coefficients.

  4. Long ranged interactions in computer simulations and for quasi-2D systems

    Energy Technology Data Exchange (ETDEWEB)

    Mazars, Martial, E-mail: Martial.Mazars@th.u-psud.f


    Taking correctly into account long ranged interactions in molecular simulations of molecular models based on classical atomistic representations are essential to obtain reliable results on model systems and in simulations of biological systems. A lot of numerical methods have been developed to this end; the most important of them are reviewed in this paper. Particular attention is paid to the analytical relations between the methods, this allows comparisons on efficiency and accuracy between them and also to proceed to precise implementations of these techniques. While most of the methods have been developed for Coulomb interactions, we give also some analytical details to apply these methods to screened Coulomb (Yukawa interactions), inverse power law and dipolar interactions. Particular types of systems, the quasi-2D systems, are also considered in this paper. Quasi-2D systems represent a large class of physical systems where the spatial extension in one direction of the space is very small by comparison to the other two. These representations are very useful to describe the properties of interfaces, surfaces, fluids confined in slab geometry, etc. In computer simulations, these systems are studied with partial periodic boundary conditions: periodic boundary conditions are taken in directions where spatial extensions are large and some other boundary conditions are taken in directions with smaller extensions. In this review, we describe also the numerical methods developed to handle long ranged interactions in numerical simulations of quasi-2D systems. The properties of quasi-2D systems depend strongly on interactions between components; more specifically electrostatic and magnetic interactions and interactions with external fields are of particular interest in these systems.

  5. Nonlinear soil-structure interaction calculations simulating the SIMQUAKE experiment using STEALTH 2D (United States)

    Tang, H. T.; Hofmann, R.; Yee, G.; Vaughan, D. K.


    Transient, nonlinear soil-structure interaction simulations of an Electric Power Research Institute, SIMQUAKE experiment were performed using the large strain, time domain STEALTH 2D code and a cyclic, kinematically hardening cap soil model. Results from the STEALTH simulations were compared to identical simulations performed with the TRANAL code and indicate relatively good agreement between all the STEALTH and TRANAL calculations. The differences that are seen can probably be attributed to: (1) large (STEALTH) vs. small (TRANAL) strain formulation and/or (2) grid discretization differences.

  6. Online simulation of classical inorganic analysis - interactive, self instructive simulations give more lab-time

    DEFF Research Database (Denmark)

    Josephsen, Jens


    (and in university programmes it often isn’t), but rather to give them experience with chemicals and methods, a computer-based laboratory simulation may function as a cheap and fast extension of student lab time. Virtual investigations seem to be a promising kind of tool [6,7,8] for several reasons...... simply following a recipe, which is probably not effective relative to the efforts. The use of pre labs and post labs may be a way to enhance the effectiveness of the work in the laboratory [4,5]. If the purpose is not that the students become perfectly trained on the manipulative side of the procedure...

  7. GSFLOW model simulations used to evaluate the impact of irrigated agriculture on surface water - groundwater interaction (United States)

    Department of the Interior — Watershed-scale coupled surface water (SW) – groundwater (GW) flow modeling was used to examine changes in streamflow and SW – GW interaction resulting from...

  8. Interactive, Secure Web-enabled Aircraft Engine Simulation Using XML Databinding Integration (United States)

    Lin, Risheng; Afjeh, Abdollah A.


    This paper discusses the detailed design of an XML databinding framework for aircraft engine simulation. The framework provides an object interface to access and use engine data. while at the same time preserving the meaning of the original data. The Language independent representation of engine component data enables users to move around XML data using HTTP through disparate networks. The application of this framework is demonstrated via a web-based turbofan propulsion system simulation using the World Wide Web (WWW). A Java Servlet based web component architecture is used for rendering XML engine data into HTML format and dealing with input events from the user, which allows users to interact with simulation data from a web browser. The simulation data can also be saved to a local disk for archiving or to restart the simulation at a later time.

  9. Microsurgery Simulator of Cerebral Aneurysm Clipping with Interactive Cerebral Deformation Featuring a Virtual Arachnoid. (United States)

    Shono, Naoyuki; Kin, Taichi; Nomura, Seiji; Miyawaki, Satoru; Saito, Toki; Imai, Hideaki; Nakatomi, Hirofumi; Oyama, Hiroshi; Saito, Nobuhito


    A virtual reality simulator for aneurysmal clipping surgery is an attractive research target for neurosurgeons. Brain deformation is one of the most important functionalities necessary for an accurate clipping simulator and is vastly affected by the status of the supporting tissue, such as the arachnoid membrane. However, no virtual reality simulator implementing the supporting tissue of the brain has yet been developed. To develop a virtual reality clipping simulator possessing interactive brain deforming capability closely dependent on arachnoid dissection and apply it to clinical cases. Three-dimensional computer graphics models of cerebral tissue and surrounding structures were extracted from medical images. We developed a new method for modifiable cerebral tissue complex deformation by incorporating a nonmedical image-derived virtual arachnoid/trabecula in a process called multitissue integrated interactive deformation (MTIID). MTIID made it possible for cerebral tissue complexes to selectively deform at the site of dissection. Simulations for 8 cases of actual clipping surgery were performed before surgery and evaluated for their usefulness in surgical approach planning. Preoperatively, each operative field was precisely reproduced and visualized with the virtual brain retraction defined by users. The clear visualization of the optimal approach to treating the aneurysm via an appropriate arachnoid incision was possible with MTIID. A virtual clipping simulator mainly focusing on supporting tissues and less on physical properties seemed to be useful in the surgical simulation of cerebral aneurysm clipping. To our knowledge, this article is the first to report brain deformation based on supporting tissues.

  10. Interactive Web-based Floodplain Simulation System for Realistic Experiments of Flooding and Flood Damage (United States)

    Demir, I.


    Recent developments in web technologies make it easy to manage and visualize large data sets with general public. Novel visualization techniques and dynamic user interfaces allow users to create realistic environments, and interact with data to gain insight from simulations and environmental observations. The floodplain simulation system is a web-based 3D interactive flood simulation environment to create real world flooding scenarios. The simulation systems provides a visually striking platform with realistic terrain information, and water simulation. Students can create and modify predefined scenarios, control environmental parameters, and evaluate flood mitigation techniques. The web-based simulation system provides an environment to children and adults learn about the flooding, flood damage, and effects of development and human activity in the floodplain. The system provides various scenarios customized to fit the age and education level of the users. This presentation provides an overview of the web-based flood simulation system, and demonstrates the capabilities of the system for various flooding and land use scenarios.

  11. Accuracy of Potential Flow Methods to Solve Real-time Ship-Tug Interaction Effects within Ship Handling Simulators

    Directory of Open Access Journals (Sweden)

    B. Nirman Jayarathne


    Full Text Available The hydrodynamic interaction effects between two vessels that are significantly different in size operating in close proximity can adversely affect the safety and handling of these vessels. Many ship handling simulator designers implement Potential Flow (PF solvers to calculate real-time interaction effects. However, these PF solvers struggle to accurately predict the complicated flow regimes that can occur, for example as the flow passes a wet transom hull or one with a drift angle. When it comes to predicting the interaction effects on a tug during a ship assist, it is essential to consider the rapid changes of the tug’s drift angle, as the hull acts against the inflow creating a complicated flow regime. This paper investigates the ability of the commercial PF solver, Futureship®, to predict the accurate interaction effects acting on tugs operating at a drift angle during ship handling operations through a case study. This includes a comparison against Computation Fluid Dynamics (CFD simulations and captive model tests to examine the suitability of the PF method for such duties. Although the PF solver can be tuned to solve streamline bodies, it needs further improvement to deal with hulls at drift angles.

  12. A Multiscale Simulation Framework to Investigate Hydrobiogeochemical Processes in the Groundwater-Surface Water Interaction Zone (United States)

    Scheibe, T. D.; Yang, X.; Song, X.; Chen, X.; Hammond, G. E.; Song, H. S.; Hou, Z.; Murray, C. J.; Tartakovsky, A. M.; Tartakovsky, G.; Yang, X.; Zachara, J. M.


    The PNNL Subsurface Scientific Focus Area (SFA) project is developing a predictive understanding of the groundwater-surface water interaction zone (termed the subsurface interaction zone, SIZ), which plays an important role in natural ecosystems as it regulates the mixing of nutrients that controls biogeochemical transformations. A key element of this research is to build a multiscale simulation framework that facilitates the integration of new mechanistic understanding from fine-scale controlled laboratory studies with diverse field-scale observations and models. The framework includes multiscale facies analysis, hybrid multiscale simulation and multilevel uncertainty quantification (UQ) analysis. Multiscale facies analysis has defined two types of geological facies: 1) subsurface facies in the aquifer adjacent to the Columbia River; and 2) riverine faciesin the riverbed alluvial sediment. These definitions and associated mapping processes provide a hierarchical structure for parameterization of hydrobiogeochemical (HBGC) processes at multiple scales. A hybrid multiscale simulation approch is used to couple high-fidelity simulations of reactive transport processes in riverine facies with coarsely-resolved simulations of the larger subsurface domain. Simulations at both scales use the same numerical code but with different grid resolutions, heterogeneity models and biogeochemical reaction networks. The hybrid multiscale simulation is able to quantify the potential impacts of biogeochemical hotspots in the alluvial layer on system behavior on a larger scale while maintaining a feasible level of computing cost. A re-scaled Multi-Level Monte Carlo (MLMC) method for UQ combines coarse-resolution simulations with a limited number of fine simulations. The new MLMC method has been applied to the field-scale domain and proved to be more accurate and efficient than existing MC methods. Our multiscale simulation framework provides an integrated model-data platform to

  13. QuVis interactive simulations: tools to support quantum mechanics instruction (United States)

    Kohnle, Antje


    Quantum mechanics holds a fascination for many students, but its mathematical complexity and counterintuitive results can present major barriers. The QuVis Quantum Mechanics Visualization Project ( aims to overcome these issues through the development and evaluation of interactive simulations with accompanying activities for the learning and teaching of quantum mechanics. Over 90 simulations are now available on the QuVis website. One collection of simulations is embedded in the Institute of Physics Quantum Physics website (, which consists of freely available resources for an introductory course in quantum mechanics starting from two-level systems. Simulations support model-building by reducing complexity, focusing on fundamental ideas and making the invisible visible. They promote engaged exploration, sense-making and linking of multiple representations, and include high levels of interactivity and direct feedback. Simulations are research-based and evaluation with students informs all stages of the development process. Simulations are iteratively refined using student feedback in individual observation sessions and in-class trials. Evaluation has shown that the simulations can help students learn quantum mechanics concepts at both the introductory and advanced undergraduate level and that students perceive simulations to be beneficial to their learning. Recent activity includes the launch of a new collection of HTML5 simulations that run on both desktop and tablet-based devices and the introduction of a goal and reward structure in simulations through the inclusion of challenges. This presentation will give an overview of the QuVis resources, highlight recent work and outline future plans. QuVis is supported by the UK Institute of Physics, the UK Higher Education Academy and the University of St Andrews.

  14. Examining How Preservice Science Teachers Navigate Simulated Parent-Teacher Conversations on Evolution and Intelligent Design (United States)

    Dotger, Sharon; Dotger, Benjamin H.; Tillotson, John


    Discussing the teaching of evolution with concerned parents is a challenge to any science teacher. Using the medical education pedagogy of standardized individuals within the field of teacher education, this article addresses how preservice science teachers elected to verbally interact with standardized parents who questioned the teaching of…

  15. Dynamic Simulation of Crime Perpetration and Reporting to Examine Community Intervention Strategies (United States)

    Yonas, Michael A.; Burke, Jessica G.; Brown, Shawn T.; Borrebach, Jeffrey D.; Garland, Richard; Burke, Donald S.; Grefenstette, John J.


    Objective: To develop a conceptual computational agent-based model (ABM) to explore community-wide versus spatially focused crime reporting interventions to reduce community crime perpetrated by youth. Method: Agents within the model represent individual residents and interact on a two-dimensional grid representing an abstract nonempirically…

  16. Using a decision support systems computer simulation model to examine HIV and tuberculosis: the Russian Federation. (United States)

    Lebcir, Reda M; Choudrie, Jyoti; Atun, Rifat A; Coker, Richard J


    The aim of this paper is to describe the development and use of a computer simulation model that can be used as a Decision Support System (DSS) to tackle the critical public health issues of HIV and HIV-related tuberculosis in the Russian Federation. This country has recently witnessed an explosion of HIV infections and a worrying spread of the Multi-Drug Resistant form of Tuberculosis (MDRTB). The conclusions drawn are that a high population coverage with Highly Active Anti-Retroviral Treatment (HAART) (75% or higher), allied with high MDRTB cure rates, reduces cumulative deaths by 60%, with limited impact below this level. This research offers a simulation model that can be applied as a DSS by public health officials to inform policy making. By doing so, ways of controlling the spread of HIV and MDRTB and reduce mortality from these serious public health threats is provided.

  17. Examinations of tRNA Range of Motion Using Simulations of Cryo-EM Microscopy and X-Ray Data

    Directory of Open Access Journals (Sweden)

    Thomas R. Caulfield


    Full Text Available We examined tRNA flexibility using a combination of steered and unbiased molecular dynamics simulations. Using Maxwell's demon algorithm, molecular dynamics was used to steer X-ray structure data toward that from an alternative state obtained from cryogenic-electron microscopy density maps. Thus, we were able to fit X-ray structures of tRNA onto cryogenic-electron microscopy density maps for hybrid states of tRNA. Additionally, we employed both Maxwell's demon molecular dynamics simulations and unbiased simulation methods to identify possible ribosome-tRNA contact areas where the ribosome may discriminate tRNAs during translation. Herein, we collected >500 ns of simulation data to assess the global range of motion for tRNAs. Biased simulations can be used to steer between known conformational stop points, while unbiased simulations allow for a general testing of conformational space previously unexplored. The unbiased molecular dynamics data describes the global conformational changes of tRNA on a sub-microsecond time scale for comparison with steered data. Additionally, the unbiased molecular dynamics data was used to identify putative contacts between tRNA and the ribosome during the accommodation step of translation. We found that the primary contact regions were H71 and H92 of the 50S subunit and ribosomal proteins L14 and L16.

  18. An examination of interactional coherence in email use in elementary school.

    NARCIS (Netherlands)

    van der Meij, Hans; de Vries, B.; Boersma, Kerst; Pieters, Julius Marie; Wegerif, Rupert


    This paper reports on a study of email use in elementary school. An analytic model consisting of a contextual, rhetorical and semantic dimension is proposed as a means to measure interactional coherence. In describing this CRS-model special attention is given to the dialogue types distinguished by

  19. Peer Groups and Substance Use: Examining the Direct and Interactive Effect of Leisure Activity (United States)

    Thorlindsson, Thorolfur; Bernburg, Jon Gunnar


    This paper explores the relationships among adolescent leisure activities, peer behavior, and substance use. We suggest that peer group interaction can have a differential effect on adolescent deviant behavior depending on the type of leisure pattern adolescents engage in. We analyze data from a representative national sample of Icelandic…

  20. Examining African American and Caucasian Interaction Patterns within Computer-Mediated Communication Environments (United States)

    Bellamy, Al; Greenfield, M. C.


    This study explored the extent to which student emotion management factors and normative orientation (belief that chat rooms have normative standards of conduct similar to face-to-face interaction) circumscribe the sending of hostile messages within electronic relay chat rooms on the Internet. A questionnaire survey collected data from 114…

  1. What Is Video Good for? Examining How Media and Story Genre Interact (United States)

    Koehler, Matthew; Yadav, Aman; Phillips, Michael; Cavazos-Kottke, Sean


    Research suggests that the educational value of a media format depends upon the ways in which its representational affordances interact with complex features of the learning environment, including learner characteristics, content domains, pedagogical strategies, and cognitive and social processes. In the current study, we sought to understand some…

  2. Drawing on Interactive Tables: Examining Students’ Flow, Collaborative Process and Learning Outcomes

    NARCIS (Netherlands)

    Gijlers, Aaltje H.; Bollen, Lars; Järvenoja, Hanna; Mykkänen, Arttu; Järvelä, Sanna; Lindwall, Oskar; Häkkinen, Päivi; Koschmann, Timothy; Tchounikine, Pierre; Ludvigsen, Sten


    This study explores collaborative knowledge construction using interactive tables for an ICT-based drawing task. Thirty-six students worked in small groups on science posters. Results show a significant learning gain from pre- to post-test. Furthermore, significant positive correlations were found

  3. The Behavioral Assessment of Social Interactions in Young Children: An Examination of Convergent and Incremental Validity (United States)

    Callahan, Emily H.; Gillis, Jennifer M.; Romanczyk, Raymond G.; Mattson, Richard E.


    Many treatment programs for individuals with an autism spectrum disorder (ASD) target social skills, and there is growing attention directed toward the development of specific interventions to improve social skills and social interactions in this population (Hestenes & Carroll, 2000; Strain & Hoyson, 2000). However, there are limited tools…

  4. Raising Language Awareness in Peer Interaction: A Cross-Context, Cross-Methodology Examination (United States)

    Sato, Masatoshi; Ballinger, Susan


    In this paper, both a cognitive and a sociocultural theoretical perspective are used to bring together findings from two studies that investigated the effects of instruction designed to enhance the potentially positive effect of peer interaction on L2 development. Despite differences between the studies' learning contexts, participants' age, and…

  5. Examining Undocumented Latino/a Student Interactions with Faculty and Institutional Agents (United States)

    Stebleton, Michael J.; Aleixo, Marina B.


    This study explored the experiences of nine undocumented Latino/a students and their perception of interactions with faculty and institutional agents at a predominantly White institution (PWI). Using Charmaz as a lens to analyze individual student interviews, three main findings resulted: sharing one's story, encountering barriers to full…

  6. FLUKA Monte Carlo Simulations about Cosmic Rays Interactions with Kaidun Meteorite

    Directory of Open Access Journals (Sweden)

    Turgay Korkut


    Full Text Available An asteroid called Kaidun fell on December 3, 1980, in Yemen (15° 0′N, 48° 18′E. Investigations on this large-sized meteorite are ongoing today. In this paper, interactions between cosmic rays-earth atmosphere and cosmic rays-Kaidun meteorite were modeled using a cosmic ray generator FLUKA Monte Carlo code. Isotope distributions and produced particles were given after these interactions. Also, simulation results were compared for these two types of interactions.

  7. Perceived Support from Adults, Interactions with Police, and Adolescents' Depressive Symptomology: An Examination of Sex, Race, and Social Class (United States)

    Tummala-Narra, Pratyusha; Sathasivam-Rueckert, Nina


    Several risk factors, including female sex, racial minority status, and family poverty, have been implicated in adolescents' depression. The present study focused on the role of one specific aspect of adolescents' ecological context, interactions with adults, in depressive symptomology. We examined the relationship between perceived support from…

  8. Teachers' Language in Interactions: An Exploratory Examination of Mental State Talk in Early Childhood Education Classrooms (United States)

    King, Elizabeth; La Paro, Karen


    Research Findings: This study examined 34 Head Start teachers' use of four categories of mental state talk (verbalizations of mental processes using emotion terms, cognition terms, desire terms, and perception terms) during naturally occurring classroom interactions. Transcriptions from classroom videos were coded for mental state talk…

  9. Skills in Social Studies Curricula in Turkey: An Examination in the Context of Socio-Cultural Interaction (United States)

    Ibrahimoglu, Zafer; San, Selda


    The aim of this study was to chronologically examine the contents of the social studies curricula implemented in Turkey in terms of skills teaching in the context of socio-cultural interaction. In the study, the social studies curricula used since 1967 were subjected to content analysis, and the skills aimed to be taught to students in the…

  10. Examining the Inclusiveness of Intercollegiate Team Climate and Its Influence on Student-Athletes' Cross-Racial Interactions (United States)

    Jones, Willis A.; Liu, Keke; Bell, Lydia F.


    We examined a student subgroup often absent from diversity research: student-athletes. We explored whether intercollegiate athletic teams are promoting an open and inclusive environment and whether creating such an environment leads to more frequent and more positive cross-racial interactions. Findings reveal that overall, coaches appear to be…

  11. Importance of a Conserved Lys/Arg Residue for Ligand/PDZ Domain Interactions as Examined by Protein Semisynthesis

    DEFF Research Database (Denmark)

    Pedersen, Søren W; Moran, Griffin E; Sereikaité, Vita


    drug targets for diseases (in the brain in particular), so understanding the molecular details of PDZ domain interactions is of fundamental importance. PDZ domains bind to a protein partner at either a C-terminal peptide or internal peptide motifs. Here, we examined the importance of a conserved Lys...

  12. Examining the Efficacy of Peer Network Interventions on the Social Interactions of High School Students with Autism Spectrum Disorder (United States)

    Sreckovic, Melissa A.; Hume, Kara; Able, Harriet


    Developing positive peer relationships is important. Unfortunately, due to challenges in social communication and increased complexity of peer groups during adolescence, many secondary students with autism spectrum disorder (ASD) engage in limited positive social interactions with peers. This study examined the effects of a peer network…

  13. Predictors of At-Risk Kindergarteners' Later Reading Difficulty: Examining Learner-by-Intervention Interactions (United States)

    Simmons, Deborah C.; Taylor, Aaron B.; Oslund, Eric L.; Simmons, Leslie E.; Coyne, Michael D.; Little, Mary E.; Rawlinson, D'Ann M.; Hagan-Burke, Shanna; Kwok, Oi-man; Kim, Minjung


    This longitudinal study examined (a) the second-grade reading outcomes of 368 children who participated in either experimental or school-designed supplemental intervention in kindergarten, and (b) the influence and interactions of learner variables and type of intervention on reading achievement. Descriptive findings indicated that percentages of…

  14. Seriously clowning: Medical clowning interaction with children undergoing invasive examinations in hospitals. (United States)

    Tener, Dafna; Ofir, Shoshi; Lev-Wiesel, Rachel; Franco, Nessia L; On, Avi


    This qualitative study examined the subjective experience of children undergoing an invasive examination in the hospital when accompanied by a medical clown. In-depth semi-structured interviews were conducted with nine such children and nine of their accompanying parents. The children were patients in two outpatient departments (Pediatric Gastroenterology and a Center for the Sexually Abused) in a hospital in Israel. Interviews were coded thematically using an Atlas.ti software program. Analysis of the interviews indicated that the intervention of the clown positively changed the children's perceptions of the hospital, of experiencing the examination, and of their life narrative. Medical clowns thus appear to be a central, meaningful, and therapeutic source for children undergoing invasive examinations in hospital, as well as for their parents. Therefore, it may be advisable to incorporate medical clowns as an integral part of medical teams performing invasive procedures and to include the clowns in all stages of the hospital visit.


    NARCIS (Netherlands)



    Numerical simulations of the interacting galaxies in the NGC 520/UGC 957 system are presented. Two sets of models were produced to investigate the postulated three-galaxy system of two colliding disk galaxies within NGC 520 and the dwarf galaxy UGC 957. The morphology and kinematics of the models

  16. Interpretation of Simulations in Interactive VR Environments: Depth Perception in Cave and Panorama

    DEFF Research Database (Denmark)

    Mullins, Michael


    of architectural concepts. Architects need to heed the dynamics set in motion by these technologies and especially of how laypersons interpret building forms and their simulations in interactive VR environments. The article presents a study which compares aspects of spatial perception in a physical environment...

  17. Experimental grid access for dynamic discovery and data transfer in distributed interactive simulation systems

    NARCIS (Netherlands)

    Tirado-Ramos, A.; Zajac, K.; Zhao, Z.; Sloot, P.M.A.; van Albada, G.D.; Bubak, M.


    Interactive Problem Solving Environments (PSEs) offer an integrated approach for constructing and running complex systems, such as distributed simulation systems. New distributed infrastructures, like the Grid, support the access to a large variety of core services and resources that can be used by


    NARCIS (Netherlands)



    The Simulated Social Interaction Test (SSIT) was translated and adjusted for use on a population of Dutch males and females. Seventy-four social phobic patients were assessed with the SSIT, a conversation test, and an interview with an independent observer. Results show that the SSIT is a relatively

  19. Simulating Matrix Crack and Delamination Interaction in a Clamped Tapered Beam (United States)

    De Carvalho, N. V.; Seshadri, B. R.; Ratcliffe, J. G.; Mabson, G. E.; Deobald, L. R.


    Blind predictions were conducted to validate a discrete crack methodology based on the Floating Node Method to simulate matrix-crack/delamination interaction. The main novel aspects of the approach are: (1) the implementation of the floating node method via an 'extended interface element' to represent delaminations, matrix-cracks and their interaction, (2) application of directional cohesive elements to infer overall delamination direction, and (3) use of delamination direction and stress state at the delamination front to determine migration onset. Overall, good agreement was obtained between simulations and experiments. However, the validation exercise revealed the strong dependence of the simulation of matrix-crack/delamination interaction on the strength data (in this case transverse interlaminar strength, YT) used within the cohesive zone approach applied in this work. This strength value, YT, is itself dependent on the test geometry from which the strength measurement is taken. Thus, choosing an appropriate strength value becomes an ad-hoc step. As a consequence, further work is needed to adequately characterize and assess the accuracy and adequacy of cohesive zone approaches to model small crack growth and crack onset. Additionally, often when simulating damage progression with cohesive zone elements, the strength is lowered while keeping the fracture toughness constant to enable the use of coarser meshes. Results from the present study suggest that this approach is not recommended for any problem involving crack initiation, small crack growth or multiple crack interaction.

  20. Realistic tool-tissue interaction models for surgical simulation and planning

    NARCIS (Netherlands)

    Misra, Sarthak


    Surgical simulators present a safe and potentially effective method for surgical training, and can also be used in pre- and intra-operative surgical planning. Realistic modeling of medical interventions involving tool-tissue interactions has been considered to be a key requirement in the development

  1. Cultural Competence Clinic: An Online, Interactive, Simulation for Working Effectively with Arab American Muslim Patients (United States)

    Smith, Brian Daniel; Silk, Kami


    Objective: This pilot study investigates the impact of an online, interactive simulation involving an Arab American Muslim patient on the knowledge, skills, and attitudes of 2nd-year medical students regarding culturally competent healthcare, both in general and specific to Arab American Muslim patients. Method: Participants (N = 199), were…


    Directory of Open Access Journals (Sweden)

    V. I. Prykhodko


    Full Text Available The results of mathematical simulation of spatial oscillations of passenger coaches for determination of forces of dynamical interaction of bodies and bogies, which are used in determination of dynamic run and strength characteristics, are presented in this paper.

  3. Interacting with a Computer-Simulated Pet: Factors Influencing Children's Humane Attitudes and Empathy (United States)

    Tsai, Yueh-Feng; Kaufman, David


    Previous research by Tsai and Kaufman (2010a, 2010b) has suggested that computer-simulated virtual pet dogs can be used as a potential medium to enhance children's development of empathy and humane attitudes toward animals. To gain a deeper understanding of how and why interacting with a virtual pet dog might influence children's social and…

  4. In-situ sampling of a large-scale particle simulation for interactive visualization and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Woodring, Jonathan L [Los Alamos National Laboratory; Ahrens, James P [Los Alamos National Laboratory; Heitmann, Katrin [Los Alamos National Laboratory


    We propose storing a random sampling of data from large scale particle simulations, such as the Roadrunner Universe MC{sup 3} cosmological simulation, to be used for interactive post-analysis and visualization. Simulation data generation rates will continue to be far greater than storage bandwidth rates and other limiting technologies by many orders of magnitude. This implies that only a very small fraction of data generated by the simulation can ever be stored and subsequently post-analyzed. The limiting technology in this situation is analogous to the problem in many population surveys: there aren't enough human resources to query a large population. To cope with the lack of resources, statistical sampling techniques are used to create a representative data set of a large population. Mirroring that situation, we propose to store a simulation-time random sampling of the particle data to cope with the bOlllenecks and support interactive, exploratory post-analysis. The particle samples are immediately stored in a level-ol-detail format for post-visualization and analysis, which amortizes the cost of post-processing for interactive visualization. Additionally, we incorporate a system for recording and visualizing sample approximation error information for confidence and importance highlighting.

  5. Studies of bicalutamide-excipients interaction by combination of molecular docking and molecular dynamics simulation. (United States)

    Li, Caixia; Wang, Jie-Xin; Le, Yuan; Chen, Jian-Feng


    While the effects of hydrophilic excipients in enhancing the dissolution rate of water-insoluble drugs have been validated, the underlying mechanism remains poorly understood, particularly at a molecular level. In this work, a combination of docking calculations and MD simulations was applied to investigate the molecular interactions between bicalutamide (BIC) and each of three excipients: lactose (LAC), hydroxypropyl methylcellulose (HPMC), and mannitol (MAN). The calculated results indicated that BIC interacted with HPMC and MAN mainly by Lennard-Jones (LJ) interactions but with LAC mainly by Coulomb (Coul) interactions. There was no hydrogen bond formed between BIC and excipient. It was shown that BIC/LAC had the biggest total solvent accessible surface area with the biggest hydrophilic area and formed the most hydrogen bonds between excipient and water. In addition to the structure analyses, BIC/LAC had both the lowest interaction energy between BIC and excipient and the lowest interaction energy between BIC/excipient and water. All these led to the best dissolution performance of BIC/LAC, which could correspond to the experimental results of dissolution test. The present study suggests that a combination of docking calculations and MD simulations, which aims at complementing the experimental work, could provide a molecular insight into the interaction between drug and excipient. It also holds the great potential to simplify the optimization process of drug delivery system and reduce both time and costs.

  6. Simulations of beam-beam and beam-wire interactions in RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung J.; Sen, Tanaji; /Fermilab; Abreu, Natalia P.; Fischer, Wolfram; /Brookhaven


    The beam-beam interaction is one of the dominant sources of emittance growth and luminosity lifetime deterioration. A current carrying wire has been proposed to compensate long-range beam-beam effects in the LHC and strong localized long-range beam-beam effects are experimentally investigated in the RHIC collider. Tune shift, beam transfer function, and beam loss rate are measured in dedicated experiments. In this paper, they report on simulations to study the effect of beam-wire interactions based on diffusive apertures, beam loss rates, and beam transfer function using a parallelized weak-strong beam simulation code (BBSIMC). The simulation results are compared with measurements performed in RHIC during 2007 and 2008.

  7. Modeling and Simulation for Exploring Human-Robot Team Interaction Requirements

    Energy Technology Data Exchange (ETDEWEB)

    Dudenhoeffer, Donald Dean; Bruemmer, David Jonathon; Davis, Midge Lee


    Small-sized and micro-robots will soon be available for deployment in large-scale forces. Consequently, the ability of a human operator to coordinate and interact with largescale robotic forces is of great interest. This paper describes the ways in which modeling and simulation have been used to explore new possibilities for human-robot interaction. The paper also discusses how these explorations have fed implementation of a unified set of command and control concepts for robotic force deployment. Modeling and simulation can play a major role in fielding robot teams in actual missions. While live testing is preferred, limitations in terms of technology, cost, and time often prohibit extensive experimentation with physical multi-robot systems. Simulation provides insight, focuses efforts, eliminates large areas of the possible solution space, and increases the quality of actual testing.

  8. Numerical Simulation of Interactions between Corrosion Pits on Stainless Steel under Loading Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Haitao; Han, En-Hou [Chinese Academy of Sciences, Shenyang (China)


    The interactions between corrosion pits on stainless steel under loading conditions are studied by using a cellular automata model coupled with finite element method at a mesoscopic scale. The cellular automata model focuses on a metal/film/electrolyte system, including anodic dissolution, passivation, diffusion of hydrogen ions and salt film hydrolysis. The Chopard block algorithm is used to improve the diffusion simulation efficiency. The finite element method is used to calculate the stress concentration on the pit surface during pit growth, and the effect of local stress and strain on anodic current is obtained by using the Gutman model, which is used as the boundary conditions of the cellular automata model. The transient current characteristics of the interactions between corrosion pits under different simulation factors including the breakdown of the passive film at the pit mouth and the diffusion of hydrogen ions are analyzed. The analysis of the pit stability product shows that the simulation results are close to the experimental conclusions.

  9. On the Use of Vortex-Fitting in the Numerical Simulation of Blade-Vortex Interaction (United States)

    Srinivasan, G. R.; VanDalsem, William (Technical Monitor)


    The usefulness of vortex-fitting in the computational fluid dynamics (CFD) methods to preserve the vortex strength and structure while convecting in a uniform free stream is demonstrated through the numerical simulations of two- and three-dimensional blade-vortex interactions. The fundamental premise of the formulation is the velocity and pressure field of the interacting vortex are unaltered either in the presence of an airfoil or a rotor blade or by the resulting nonlinear interactional flowfield. Although, the governing Euler and Navier-Stokes equations are nonlinear and independent solutions cannot be superposed, the interactional flowfield can be accurately captured by adding and subtracting the flowfield of the convecting vortex at each instant. The aerodynamics and aeroacoustics of two- and three-dimensional blade-vortex interactions have been calculated in Refs. 1-6 using this concept. Some of the results from these publications and similar other published material will be summarized in this paper.

  10. Molecular dynamics simulation of the interaction between protein tyrosine phosphatase 1B and aryl diketoacid derivatives. (United States)

    Wang, Qiang; Gao, Jun; Liu, Yongjun; Liu, Chengbu


    The protein tyrosine phosphatase 1B (PTP-1B) is acknowledged as an outstanding therapeutic target for the treatment of diabetes, obesity and cancer. In this work, six aryl diketoacid compounds have been studied on the basis of molecular dynamics simulations. Hydrogen bonds, binding energies and conformation changes of the WPD loop have been analyzed. The results indicated that their activation model falls into two parts: the target region of the monomeric aryl diketoacid compounds is the active site, whereas the target region of the dimeric aryl diketoacid compounds is the WPD loop or the R loop. The van der Waals interactions exhibit stronger effects than the short-range electrostatic interactions. The van der Waals interaction energy and the IC50 values exhibit an approximately exponential relationship. Furthermore, the van der Waals interactions cooperate with the hydrogen bond interactions. This study provides a more thorough understanding of the PTP-1B inhibitor binding processes. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. An Examination of Options to Reduce Underway Training Days through the Use of Simulation (United States)


    better exploit simulation, the Deputy Chief of Naval Operations for Resources , Requirements, and Assessments, Assessment Division (OPNAV N81), asked the...NCO) antimine warfare (AMW) strike warfare ( STW ) fleet support operations–medical (FSO-M) intelligence (INT) mobility–damage control (MOB-D). The...Number of exercises M is si o n a re a 0 100 200 300 400 500 600 MOB-S C2W MOB-E MOB-N SUW AW ASW CCC MIW NCO AMW STW INT FSO-M MOB-D Summary

  12. Monte Carlo simulation of structure and nanoscale interactions in polymer nanocomposites. (United States)

    Zhang, Qiang; Archer, Lynden A


    Off-lattice Monte Carlo simulations in the canonical ensemble are used to study polymer-particle interactions in nanocomposite materials. Specifically, nanoscale interactions between long polymer chains (N=550) and strongly adsorbing colloidal particles of comparable size to the polymer coils are quantified and their influence on nanocomposite structure and dynamics investigated. In this work, polymer-particle interactions are computed from the integrated force-distance curve on a pair of particles approaching each other in an isotropic polymer medium. Two distinct contributions to the polymer-particle interaction potential are identified: a damped oscillatory component that is due to chain density fluctuations and a steric repulsive component that arises from polymer confinement between the surfaces of approaching particles. Significantly, in systems where particles are in a dense polymer melt, the latter effect is found to be much stronger than the attractive polymer bridging effect. The polymer-particle interaction potential and the van der Waals potential between particles determine the equilibrium particle structure. Under thermodynamic equilibrium, particle aggregation is observed and there exists a fully developed polymer-particle network at a particle volume fraction of 11.3%. Near-surface polymer chain configurations deduced from our simulations are in good agreement with results from previous simulation studies. (c) 2004 American Institute of Physics

  13. Interaction between Pheromone and Its Receptor of the Fission Yeast Schizosaccharomyces pombe Examined by a Force Spectroscopy Study

    Directory of Open Access Journals (Sweden)

    Shintaro Sasuga


    Full Text Available Interaction between P-factor, a peptide pheromone composed of 23 amino acid residues, and its pheromone receptor, Mam2, on the cell surface of the fission yeast Schizosaccharomyces pombe was examined by an atomic force microscope (AFM. An AFM tip was modified with P-factor derivatives to perform force curve measurements. The specific interaction force between P-factor and Mam2 was calculated to be around 120 pN at a probe speed of 1.74 μm/s. When the AFM tip was modified with truncated P-factor derivative lacking C-terminal Leu, the specific interaction between the tip and the cell surface was not observed. These results were also confirmed with an assay system using a green fluorescent protein (GFP reporter gene to monitor the activation level of signal transduction following the interaction of Mam2 with P-factor.

  14. The "resident's dilemma"? Values and strategies of medical residents for education interactions: a cellular automata simulation. (United States)

    Heckerling, P S; Gerber, B S; Weiner, S J


    Medical residents engage in formal and informal education interactions with fellow residents during the working day, and can choose whether to spend time and effort on such interactions. Time and effort spent on such interactions can bring learning and personal satisfaction to residents, but may also delay completion of clinical work. Using hypothetical cases, we assessed the values and strategies of internal medicine residents at one hospital for both cooperative and non-cooperative education interactions with fellow residents. We then used these data and cellular automata models of two-person games to simulate repeated interactions between residents, and to determine which strategies resulted in greatest accrued value. We conducted sensitivity analyses on several model parameters, to test the robustness of dominant strategies to model assumptions. Twenty-nine of the 57 residents (50.9%) valued cooperation more than non-cooperation no matter what the other resident did during the current interaction. Similarly, thirty-six residents (63.2%) endorsed an unconditional always-cooperate strategy no matter what the other resident had done during their previous interaction. In simulations, an always-cooperate strategy accrued more value (776.42 value units) than an aggregate of strategies containing non-cooperation components (675.0 value units, p = 0.052). Only when the probability of strategy errors reached 50%, or when values were re-ordered to match those of a Prisoner's Dilemma, did non-cooperation-based strategies accrue the most value. Cooperation-based values and strategies were most frequent among our residents, and dominated in simulations of repeated education interactions between them.

  15. Euler-Lagrange Simulations of Shock Wave-Particle Cloud Interaction (United States)

    Koneru, Rahul; Rollin, Bertrand; Ouellet, Frederick; Park, Chanyoung; Balachandar, S.


    Numerical experiments of shock interacting with an evolving and fixed cloud of particles are performed. In these simulations we use Eulerian-Lagrangian approach along with state-of-the-art point-particle force and heat transfer models. As validation, we use Sandia Multiphase Shock Tube experiments and particle-resolved simulations. The particle curtain upon interaction with the shock wave is expected to experience Kelvin-Helmholtz (KH) and Richtmyer-Meshkov (RM) instabilities. In the simulations evolving the particle cloud, the initial volume fraction profile matches with that of Sandia Multiphase Shock Tube experiments, and the shock Mach number is limited to M =1.66. Measurements of particle dispersion are made at different initial volume fractions. A detailed analysis of the influence of initial conditions on the evolution of the particle cloudis presented. The early time behavior of the models is studied in the fixed bed simulations at varying volume fractions and shock Mach numbers.The mean gas quantities are measured in the context of 1-way and 2-way coupled simulations. This work was supported by the U.S. Department of Energy, National Nuclear Security Administration, Advanced Simulation and Computing Program, as a Cooperative Agreement under the Predictive Science Academic Alliance Program, Contract No. DE-NA0002378.

  16. A unified framework for spiking and gap-junction interactions in distributed neuronal network simulations (United States)

    Hahne, Jan; Helias, Moritz; Kunkel, Susanne; Igarashi, Jun; Bolten, Matthias; Frommer, Andreas; Diesmann, Markus


    Contemporary simulators for networks of point and few-compartment model neurons come with a plethora of ready-to-use neuron and synapse models and support complex network topologies. Recent technological advancements have broadened the spectrum of application further to the efficient simulation of brain-scale networks on supercomputers. In distributed network simulations the amount of spike data that accrues per millisecond and process is typically low, such that a common optimization strategy is to communicate spikes at relatively long intervals, where the upper limit is given by the shortest synaptic transmission delay in the network. This approach is well-suited for simulations that employ only chemical synapses but it has so far impeded the incorporation of gap-junction models, which require instantaneous neuronal interactions. Here, we present a numerical algorithm based on a waveform-relaxation technique which allows for network simulations with gap junctions in a way that is compatible with the delayed communication strategy. Using a reference implementation in the NEST simulator, we demonstrate that the algorithm and the required data structures can be smoothly integrated with existing code such that they complement the infrastructure for spiking connections. To show that the unified framework for gap-junction and spiking interactions achieves high performance and delivers high accuracy in the presence of gap junctions, we present benchmarks for workstations, clusters, and supercomputers. Finally, we discuss limitations of the novel technology. PMID:26441628

  17. Numerical examination of acousto-optic Bragg interactions for profiled lightwaves using a transfer function formalism (United States)

    Chatterjee, Monish R.; Almehmadi, Fares S.


    Classically, acousto-optic (AO) interactions comprise scattering of photons by energetic phonons into higher and lower orders. Standard weak interaction theory describes diffraction in the Bragg regime as the propagation of a uniform plane wave of light through a uniform plane wave of sound, resulting in the well-known first- and zeroth-order diffraction. Our preliminary investigation of the nature of wave diffraction and photon scattering from a Bragg cell under intensity feedback with profiled light beams indicates that the diffracted (upshifted photon) light continues to maintain the expected (uniform plane wave) behavior versus the optical phase shift in the cell within a small range of the Q-parameter, and at larger Qs, begins to deviate. Additionally, we observe the asymptotic axial shift of the beam center as predicted by the transfer function formalism.

  18. Towards Space Solar Power - Examining Atmospheric Interactions of Power Beams with the HAARP Facility

    CERN Document Server

    Leitgab, M


    In the most common space solar power (SSP) system architectures, solar energy harvested by large satellites in geostationary orbit is transmitted to Earth via microwave radiation. Currently, only limited information about the interactions of microwave beams with energy densities of several tens to hundreds of W/m$^2$ with the different layers of the atmosphere is available. Governmental bodies will likely require detailed investigations of safety and atmospheric effects of microwave power beams before issuing launch licenses for SSP satellite systems. This paper proposes to collect representative and comprehensive data of the interaction of power beams with the atmosphere by extending the infrastructure of the High Frequency Active Auroral Research Program (HAARP) facility in Alaska, USA. Estimates of the transmission infrastructure performance as well as measurement devices and scientific capabilities of possible upgrade scenarios will be discussed. The proposed upgrade of the HAARP facility is expected to d...

  19. Personal and Social Interactions Between Young Girls and Scientists: Examining Critical Aspects for Identity Construction (United States)

    Farland-Smith, Donna


    At a 5-day summer camp designed for middle-school girls (N = 50), fifth through ninth-grade students were able to identify with individual scientists and learn more about the science field. Data from the girls' journals, pictorial representations, and field notes demonstrated that these young women related to scientists who actively engaged them in hands-on, problem-based activities and had a sense of humor while doing so. Girls closely identified with science fields that offer an opportunity for travel and for interaction with animals. In addition, it is evident that the girls' personal and social interactions shaped their perceptions of scientists and helped them internalize their experiences as members of a science community in relation to their overall science identities.

  20. Simulations of collisions between N-body classical systems in interaction; Simulations de collisions entre systemes classiques a n-corps en interaction

    Energy Technology Data Exchange (ETDEWEB)

    Morisseau, Francois [Laboratoire de Physique Corpusculaire de CAEN, ENSICAEN, Universite de Caen Basse-Normandie, UFR des Sciences, 6 bd Marechal Juin, 14050 Caen Cedex (France)


    The Classical N-body Dynamics (CNBD) is dedicated to the simulation of collisions between classical systems. The 2-body interaction used here has the properties of the Van der Waals potential and depends on just a few parameters. This work has two main goals. First, some theoretical approaches assume that the dynamical stage of the collisions plays an important role. Moreover, colliding nuclei are supposed to present a 1. order liquid-gas phase transition. Several signals have been introduced to show this transition. We have searched for two of them: the bimodality of the mass asymmetry and negative heat capacity. We have found them and we give an explanation of their presence in our calculations. Second, we have improved the interaction by adding a Coulomb like potential and by taking into account the stronger proton-neutron interaction in nuclei. Then we have figured out the relations that exist between the parameters of the 2-body interaction and the properties of the systems. These studies allow us to fit the properties of the classical systems to those of the nuclei. In this manuscript the first results of this fit are shown. (author)

  1. Interactions between bar dynamics and herbaceous vegetation in gravel bed rivers: numerical simulations using BASEMENT (United States)

    Siviglia, Annunziato; Tettamanti, Stefano; Bertoldi, Walter; Toffolon, Marco; Vetsch, David; Francalanci, Simona


    A new 2D morphodynamic model for gravel bed rivers have been used to investigate the interaction between alternate bar dynamics and herbaceous vegetation. In particular, bed topography evolution has been coupled with the growth of vegetation, included as a function of the access to ground water. Numerical simulations were performed using the code BASEMENT (Vetsch et al., 2013), with the addition of a new submodel, dealing with the numerical description of the vegetation. The vegetation was allowed to grow during the dry season on exposed areas, and the vertical distribution of peak biomass was modeled as a function of the bed elevation, using a simple analytical formulation, following Marani et al. (2013). Flow resistance was divided into a component exerted by the bed and a component exerted by vegetation (Crosato and Saleh, 2010; Li and Millar, 2011); in this way we reproduced both the decrease in bed shear stress, reducing the sediment transport capacity of the flow within the plants, and the increase in hydraulic resistance, reducing flow velocity. The model was applied to a hypothetical case study, with grain size, longitudinal slope, and hydrological regime similar to that of the Magra River (Italy). A straight river reach, 125 m wide and 20 km long was simulated. Starting from an initially flat configuration, the river developed its own bar morphology, under steady formative conditions. After reaching a dynamic equilibrium, we allowed the vegetation to grow and interact with the morphodynamic evolution, reproducing a sequence of floods and growing seasons at low flow. We assumed that vegetation can be uprooted only if the bed shear stress exceeds a fixed threshold. Different scenarios were examined, varying the effect of vegetation in terms of increased resistance and threshold for uprooting (i.e. added sediment cohesion). Preliminary results confirmed that the herbaceous vegetation has a stabilizing effect on river morphology. As the density and strength of

  2. Examining molecular clouds in the Galactic Centre region using X-ray reflection spectra simulations (United States)

    Walls, M.; Chernyakova, M.; Terrier, R.; Goldwurm, A.


    In the centre of our Galaxy lies a supermassive black hole, identified with the radio source Sagittarius A⋆. This black hole has an estimated mass of around 4 million solar masses. Although Sagittarius A⋆ is quite dim in terms of total radiated energy, having a luminosity that is a factor of 1010 lower than its Eddington luminosity, there is now compelling evidence that this source was far brighter in the past. Evidence derived from the detection of reflected X-ray emission from the giant molecular clouds in the Galactic Centre region. However, the interpretation of the reflected emission spectra cannot be done correctly without detailed modelling of the reflection process. Attempts to do so can lead to an incorrect interpretation of the data. In this paper, we present the results of a Monte Carlo simulation code we developed in order to fully model the complex processes involved in the emerging reflection spectra. The simulated spectra can be compared to real data in order to derive model parameters and constrain the past activity of the black hole. In particular, we apply our code to observations of Sagittarius B2, in order to constrain the position and density of the cloud and the incident luminosity of the central source. The results of the code have been adapted to be used in XSPEC by a large community of astronomers.

  3. A reusable simulation model to evaluate the effects of walk-in for diagnostic examinations

    NARCIS (Netherlands)

    Braaksma, Aleida; Kortbeek, Nikky; Smid, Kees; Sprengers, Marieke E.S.


    Enabling patients to walk in for their diagnostic examination without an appointment has considerable potential in terms of quality of care, patient service, and system efficiency. We present a model to evaluate the effect of implementing a combined walk-in and appointment system, offering

  4. Path Analysis Examining Self-Efficacy and Decision-Making Performance on a Simulated Baseball Task (United States)

    Hepler, Teri J.; Feltz, Deborah L.


    The purpose of this study was to examine the relationship between decision-making self-efficacy and decision-making performance in sport. Undergraduate students (N = 78) performed 10 trials of a decision-making task in baseball. Self-efficacy was measured before performing each trial. Decision-making performance was assessed by decision speed and…

  5. Coupled fluid-structure interaction simulation of floating offshore wind turbines and waves: a large eddy simulation approach (United States)

    Calderer, Antoni; Guo, Xin; Shen, Lian; Sotiropoulos, Fotis


    We develop a computational framework for simulating the coupled interaction of complex floating structures with large-scale ocean waves and atmospheric turbulent winds. The near-field approach features a partitioned fluid-structure interaction model (FSI) combining the curvilinear immersed boundary (CURVIB) method of Borazjani and Sotiropoulos (J. Comput. Phys. 2008) and the two-phase flow level set formulation of Kang and Sotiropoulos (Adv. in Water Res. 2012) and is capable of solving complex free-surface flows interacting non-linearly with complex real life floating structures. The near-field solver is coupled with a large-scale wave and wind model based on the two-fluid approach of Yang and Shen (J. Comput. Phys. 2011) which integrates a viscous Navier-Stokes solver with undulatory boundaries for the motion of the air and an efficient potential-flow based wave solver. The large-scale turbulent wind is incorporated from the far-field solver to the near-field solver by feeding into the latter inlet boundary conditions. The wave field is incorporated to the near-field solver by using the pressure-forcing method of Guo and Shen (J. Comput. Phys. 2009) which has been appropriately adapted to the level set method. The algorithm for coupling the two codes has been validated for a variety of wave cases including a broadband spectrum showing excellent agreement when compared to theoretical results. Finally, the capabilities of the numerical framework are demonstrated by carrying out large eddy simulation (LES) of a floating wind turbine interacting with realistic ocean wind and wave conditions.

  6. Selection bias: Examining the feasibility, utility, and participant receptivity to incorporating simulation into the general surgery residency selection process. (United States)

    Gardner, Aimee K; Steffes, Christopher P; Nepomnayshy, Dmitry; Nicholas, Cate; Widmann, Warren D; Fitzgibbons, Shimae C; Dunkin, Brian J; Jones, Daniel B; Paige, John T


    Opportunities exist to revise the current residency selection process to capture desirable candidate competencies. We examined the extent to which components of the American College of Surgeons/Association for Surgical Education simulation-based medical student curriculum combined with a teamwork activity could be used as potential screening method. Students participated in a workshop consisting of training/evaluation of knot tying, suturing, airway management, gowning/gloving, and teamwork. Surveys were given to medical students (MS) and faculty/resident/staff (FRS) to examine their opinions about the residency screening process, the most critical competencies to assess, and the effectiveness of each station for candidate evaluation. Communication (FRS, 4.86 ± .35; MS, 4.93 ± .26), leadership (FRS, 4.41 ± .80; MS, 4.5 ± .76), judgment (FRS, 4.62 ± .74; MS, 4.67 ± .62), professionalism (FRS, 4.64 ± .73; MS, 5.00 ± .00), integrity (FRS, 4.71 ± .78; MS, 4.87 ± .35), and grit/resilience (FRS, 4.71 ± .78; MS, 4.53 ± .74) were considered most valuable for candidate screening. The simulation-based curriculum for evaluation of residency candidates was rated lowest by both groups. Open response comments indicated positive perceptions of this process. Employing simulation to assess candidates may be most beneficial for examining nontechnical attributes. Future work should continue to explore this area. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Methods for simulation-based analysis of fluid-structure interaction.

    Energy Technology Data Exchange (ETDEWEB)

    Barone, Matthew Franklin; Payne, Jeffrey L.


    Methods for analysis of fluid-structure interaction using high fidelity simulations are critically reviewed. First, a literature review of modern numerical techniques for simulation of aeroelastic phenomena is presented. The review focuses on methods contained within the arbitrary Lagrangian-Eulerian (ALE) framework for coupling computational fluid dynamics codes to computational structural mechanics codes. The review treats mesh movement algorithms, the role of the geometric conservation law, time advancement schemes, wetted surface interface strategies, and some representative applications. The complexity and computational expense of coupled Navier-Stokes/structural dynamics simulations points to the need for reduced order modeling to facilitate parametric analysis. The proper orthogonal decomposition (POD)/Galerkin projection approach for building a reduced order model (ROM) is presented, along with ideas for extension of the methodology to allow construction of ROMs based on data generated from ALE simulations.

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

    DEFF Research Database (Denmark)

    Borlund, Pia


    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...... partly via citation analysis by use of Web of Science®, and partly by systematic search of online repositories. On this basis, 67 individual publications were identified and they constitute the sample of analysis. Findings – The analysis reveals a need for clarifications of how to use simulated work task...... 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...

  9. The Challenge of Grounding Planning in Simulation with an Interactive Model Development Environment (United States)

    Clement, Bradley J.; Frank, Jeremy D.; Chachere, John M.; Smith, Tristan B.; Swanson, Keith J.


    A principal obstacle to fielding automated planning systems is the difficulty of modeling. Physical systems are modeled conventionally based on specification documents and the modeler's understanding of the system. Thus, the model is developed in a way that is disconnected from the system's actual behavior and is vulnerable to manual error. Another obstacle to fielding planners is testing and validation. For a space mission, generated plans must be validated often by translating them into command sequences that are run in a simulation testbed. Testing in this way is complex and onerous because of the large number of possible plans and states of the spacecraft. Though, if used as a source of domain knowledge, the simulator can ease validation. This paper poses a challenge: to ground planning models in the system physics represented by simulation. A proposed, interactive model development environment illustrates the integration of planning and simulation to meet the challenge. This integration reveals research paths for automated model construction and validation.

  10. Electron-Anode Interactions in Particle-in-Cell Simulations of Applied-B Ion Diodes

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, J.E.; Cuneo, M.D.; Johnson, D.J.; Mehlhorn, T.A.; Pointon, T.D.; Renk, T.J.; Stygar, W.A.; Vesey, R.A.


    Particle-in-cell simulations of applied-B ion diodes using the QUICKSILVER code have been augmented with Monte Carlo calculations of electron-anode interactions (reflection and energy deposition). Extraction diode simulations demonstrate a link between the instability evolution and increased electron loss and anode heating. Simulations of radial and extraction ion diodes show spatial non-uniformity in the predicted electron loss profile leading to hot spots on the anode that rapidly exceed the 350-450 {degree}C range, known to be sufficient for plasma formation on electron-bombarded surfaces. Thermal resorption calculations indicate complete resorption of contaminants with 15-20 kcal/mole binding energies in high-dose regions of the anode during the power pulse. Comparisons of parasitic ion emission simulations and experiment show agreement in some aspects; but also highlight the need for better ion source, plasma, and neutral gas models.

  11. Syndrome Specificity and Mother-Child Interactions: Examining Positive and Negative Parenting across Contexts and Time (United States)

    Blacher, Jan; Baker, Bruce L.; Kaladjian, Araksia


    This study examined the extent to which child syndromes and observation context related to mothers' parenting behaviors. Longitudinal observations were conducted of parenting behavior across ages 3, 4, and 5 years during structured and unstructured activities. The 183 participants included mothers of children with autism spectrum disorders,…

  12. Examination Of Si-Ge Heterostructure Nanowire Growth Using Monte Carlo Simulation (United States)

    Nastovjak, A. G.; Neizvestny, I. G.; Shwartz, N. L.


    The process of Si-Ge heterostructures formation in nanowires (NWs) grown by vapor-liquid-solid mechanism was investigated using Monte Carlo simulation. Dependences of catalyst drop composition on temperature, flux intensity and nanowire diameter were obtained. Periodical oscillations of drop composition near mean value were observed. Oscillation results from layer-by-layer growth at the drop-whisker interface and necessity of supersaturation onset to start new layer formation. It was demonstrated that it is impossible to grow atomically abrupt axial heterojunctions via classical vapor-liquid-solid mechanism due to gradual change of catalyst drop composition when switching the fluxes. This phenomenon is the main reason of heterojunction blurriness. Junction abruptness was found to be dependent on nanowhisker diameter: in adsorption-induced growth mode abruptness of heterojunction decreases with diameter and in diffusion-induced mode it increases.

  13. Internal wave attractors examined using laboratory experiments and 3D numerical simulations

    CERN Document Server

    Brouzet, Christophe; Scolan, H; Ermanyuk, E V; Dauxois, Thierry


    In the present paper, we combine numerical and experimental approaches to study the dynamics of stable and unstable internal wave attractors. The problem is considered in a classic trapezoidal setup filled with a uniformly stratified fluid. Energy is injected into the system at global scale by the small-amplitude motion of a vertical wall. Wave motion in the test tank is measured with the help of conventional synthetic schlieren and PIV techniques. The numerical setup closely reproduces the experimental one in terms of geometry and the operational range of the Reynolds and Schmidt numbers. The spectral element method is used as a numerical tool to simulate the nonlinear dynamics of a viscous salt-stratified fluid. We show that the results of three-dimensional calculations are in excellent qualitative and quantitative agreement with the experimental data, including the spatial and temporal parameters of the secondary waves produced by triadic resonance instability. Further, we explore experimentally and numeri...

  14. Use of mannequin-based simulation to decrease student anxiety prior to interacting with male teaching associates. (United States)

    Pugh, Carla M; Iannitelli, Katherine Blossfield; Rooney, Deborah; Salud, Lawrence


    Previous studies have compared the usefulness of teaching associates versus mannequin trainers for learning physical exam skills. Little work has been done to assess the usefulness of mannequin trainers prior to students' interaction with teaching associates. We studied the effects of mannequin-based simulators on student comfort levels toward learning the male genitourinary examination. First-year medical students (N = 346) were surveyed before and after a mannequin-based curriculum to assess their comfort levels toward learning the male genitourinary examination. The mannequin-based curriculum significantly increased (p exam. However, the pre-post improvements were small, and on average students only progressed from being "very uncomfortable" to "somewhat comfortable." The intimate nature of the examination was the top cause of anxiety toward learning the male genitourinary exam. Students were least comfortable with the digital rectal examination at the beginning of class. We suggest that mannequin-based simulators be used prior to students' experience with male teaching associates when learning the male genitourinary exam.

  15. Examination of Industrial Symbiosis Potential Interactions in an Industrial Area Of NE Greece

    Directory of Open Access Journals (Sweden)

    G. Gaidajis


    Full Text Available This paper considers the potential contribution of Industrial Symbiosis in fostering environmental and economical benefits in the area of Nea Karvali, Kavala, Greece. Industrial Symbiosis describes the mutualistic interaction of different industries for beneficial reuse of waste flows or energy cascading that results in a more resource-efficient production system and fewer adverse environmental impacts. Results from the case study presented in this paper, show that the implementation of symbiotic relationships in the industrial area under study, would lead to significant environmental benefits (GHG reduction, reduction on natural sources consumption and would give a boost to the local economical sector by developing new business opportunities.

  16. Transfer of real-time ultrasound video of FAST examinations from a simulated disaster scene via a mobile phone. (United States)

    Adhikari, Srikar; Blaivas, Michael; Lyon, Matthew; Shiver, Stephen


    Disaster management is a complex and difficult undertaking that may involve limited health care resources and evaluation of multiple victims. The objectives of this study were to evaluate the feasibility of real-time ultrasound video transmission from a simulated disaster triage location via commercially available video mobile phones and assess the ability of emergency physicians to accurately interpret the transmitted video of Focused Assessment with Sonography for Trauma (FAST) ultrasound examinations. This was a prospective, observational study that took place at a simulated disaster scene put on for an Advanced Disaster Life Support (ADLS) course. The second component occurred at a Level I academic urban emergency department (ED) with an annual census of 78,000. Nineteen subjects at a simulated disaster scene were scanned using a SonoSite Titan ultrasound system (Bothell, Washington USA). An off-the-shelf, basic, video-capable mobile phone was used to record each ultrasound examination; and then immediately transmit the videos to another mobile phone approximately 170 miles away. The transmitted video was received by three emergency physicians with hospital credentialing in emergency ultrasound. Each FAST examination video was assessed for pathology, such as free fluid. The reviewers graded the image quality and documented the overall confidence level regarding whether or not a complete and adequate examination was visualized. Spearman's rank correlation coefficient was used to examine the agreement between the reviewers and the sonologist who performed the ultrasound examinations. A total of 19 videos were transmitted. The median time for transmission of a video was 82.5 seconds (95% CI, 67.7 seconds-97.3 seconds). No video failed to transmit correctly on the first attempt. The image quality ratings for the three reviewers were 7.7, 7.5, and 7.4 on a 10-point Likert scale. There was a moderate agreement between the reviewers and sonologist in image quality

  17. Interaction effects among multiple job demands: an examination of healthcare workers across different contexts. (United States)

    Jimmieson, Nerina L; Tucker, Michelle K; Walsh, Alexandra J


    Simultaneous exposure to time, cognitive, and emotional demands is a feature of the work environment for healthcare workers, yet effects of these common stressors in combination are not well established. Survey data were collected from 125 hospital employees (Sample 1, Study 1), 93 ambulance service employees (Sample 2, Study 1), and 380 aged care/disability workers (Study 2). Hierarchical multiple regressions were conducted. In Sample 1, high cognitive demand exacerbated high emotional demand on psychological strain and job burnout, whereas the negative effect of high emotional demand was not present at low cognitive demand. In Sample 2, a similar pattern between emotional demand and time demand on stress-remedial intentions was observed. In Study 2, emotional demand × time demand and time demand × cognitive demand interactions again revealed that high levels of two demands were stress-exacerbating and low levels of one demand neutralized the other. A three-way interaction on job satisfaction showed the negative impact of emotional demand was exacerbated when both time and cognitive demands were high, creating a "triple disadvantage" of job demands. The results demonstrate that reducing some job demands helps attenuate the stressful effects of other job demands on different employee outcomes.

  18. A physical-based gas-surface interaction model for rarefied gas flow simulation (United States)

    Liang, Tengfei; Li, Qi; Ye, Wenjing


    Empirical gas-surface interaction models, such as the Maxwell model and the Cercignani-Lampis model, are widely used as the boundary condition in rarefied gas flow simulations. The accuracy of these models in the prediction of macroscopic behavior of rarefied gas flows is less satisfactory in some cases especially the highly non-equilibrium ones. Molecular dynamics simulation can accurately resolve the gas-surface interaction process at atomic scale, and hence can predict accurate macroscopic behavior. They are however too computationally expensive to be applied in real problems. In this work, a statistical physical-based gas-surface interaction model, which complies with the basic relations of boundary condition, is developed based on the framework of the washboard model. In virtue of its physical basis, this new model is capable of capturing some important relations/trends for which the classic empirical models fail to model correctly. As such, the new model is much more accurate than the classic models, and in the meantime is more efficient than MD simulations. Therefore, it can serve as a more accurate and efficient boundary condition for rarefied gas flow simulations.

  19. Multirate Simulations of String Vibrations Including Nonlinear Fret-String Interactions Using the Functional Transformation Method

    Directory of Open Access Journals (Sweden)

    R. Rabenstein


    Full Text Available The functional transformation method (FTM is a well-established mathematical method for accurate simulations of multidimensional physical systems from various fields of science, including optics, heat and mass transfer, electrical engineering, and acoustics. This paper applies the FTM to real-time simulations of transversal vibrating strings. First, a physical model of a transversal vibrating lossy and dispersive string is derived. Afterwards, this model is solved with the FTM for two cases: the ideally linearly vibrating string and the string interacting nonlinearly with the frets. It is shown that accurate and stable simulations can be achieved with the discretization of the continuous solution at audio rate. Both simulations can also be performed with a multirate approach with only minor degradations of the simulation accuracy but with preservation of stability. This saves almost 80% of the computational cost for the simulation of a six-string guitar and therefore it is in the range of the computational cost for digital waveguide simulations.

  20. College Students' Responses to Suicidal Content on Social Networking Sites: An Examination Using a Simulated Facebook Newsfeed. (United States)

    Corbitt-Hall, Darcy J; Gauthier, Jami M; Davis, Margaret T; Witte, Tracy K


    Although Facebook has a peer-initiated suicide prevention protocol, little is known about users' abilities to notice, recognize, and appropriately interpret suicidal content or about their willingness to intervene. In this study, 468 college students were randomly assigned to interact with a simulated Facebook newsfeed containing content reflecting various suicide risk levels. A larger proportion of those exposed to content reflecting moderate and severe suicide risk noticed, recognized, appropriately interpreted, and endorsed taking action to intervene, as compared to those exposed to content representing no or low risk. Overall, results indicate that college students are responsive to suicidal content on Facebook. © 2016 The American Association of Suicidology.

  1. Water-Energy Nexus: Examining The Crucial Connection Through Simulation Based Optimization (United States)

    Erfani, T.; Tan, C. C.


    With a growing urbanisation and the emergence of climate change, the world is facing a more water constrained future. This phenomenon will have direct impacts on the resilience and performance of energy sector as water is playing a key role in electricity generation processes. As energy is becoming a thirstier resource and the pressure on finite water sources is increasing, modelling and analysing this closely interlinked and interdependent loop, called 'water-energy nexus' is becoming an important cross-disciplinary challenge. Conflict often arises in transboundary river where several countries share the same source of water to be used in productive sectors for economic growth. From the perspective of the upstream users, it would be ideal to store the water for hydropower generation and protect the city against drought whereas the downstream users need the supply of water for growth. This research use the case study on the transboundary Blue Nile River basin located in the Middle East where the Ethiopian government decided to invest on building a new dam to store the water and generate hydropower. This leads to an opposition by downstream users as they believe that the introduction of the dam would reduce the amount of water available downstream. This calls for a compromise management where the reservoir operating rules need to be derived considering the interdependencies between the resources available and the requirements proposed by all users. For this, we link multiobjective optimization algorithm to water-energy use simulation model to achieve effective management of the transboundary reservoir operating strategies. The objective functions aim to attain social and economic welfare by minimizing the deficit of water supply and maximizing the hydropower generation. The study helps to improve the policies by understanding the value of water and energy in their alternative uses. The results show how different optimal reservoir release rules generate different

  2. Examining relations between locus of control, loneliness, subjective well-being, and preference for online social interaction. (United States)

    Ye, Yinghua; Lin, Lin


    The unprecedented popularity of online communication has raised interests and concerns among the public as well as in scholarly circles. Online communications have pushed people farther away from one another. This study is a further examination of the effects of online communications on well-being, in particular: Locus of control, Loneliness, Subjective well-being, and Preference for online social interaction. Chinese undergraduate students (N = 260; 84 men, 176 women; M age = 20.1 yr., SD = 1.2) were questioned about demographic information and use of social media as well as four previously validated questionnaires related to well-being. Most participants used QQ, a popular social networking program, as the major channel for online social interactions. Locus of control was positively related to Loneliness and Preference for online social interaction, but negatively related to Subjective well-being; Loneliness (positively) and Subjective well-being (negatively) were related to Preference for online social interaction; and Loneliness and Subjective well-being had a full mediating effect between the relationships of Locus of control and Preference for online social interaction. The findings of the study showed that more lonely, unhappy, and externally controlled students were more likely to be engaged in online social interaction. Improving students' locus of control, loneliness, and happiness may help reduce problematic Internet use.

  3. Investigation of prescribed movement in fluid-structure interaction simulation for the human phonation process. (United States)

    Zörner, S; Kaltenbacher, M; Döllinger, M


    In a partitioned approach for computational fluid-structure interaction (FSI) the coupling between fluid and structure causes substantial computational resources. Therefore, a convenient alternative is to reduce the problem to a pure flow simulation with preset movement and applying appropriate boundary conditions. This work investigates the impact of replacing the fully-coupled interface condition with a one-way coupling. To continue to capture structural movement and its effect onto the flow field, prescribed wall movements from separate simulations and/or measurements are used. As an appropriate test case, we apply the different coupling strategies to the human phonation process, which is a highly complex interaction of airflow through the larynx and structural vibration of the vocal folds (VF). We obtain vocal fold vibrations from a fully-coupled simulation and use them as input data for the simplified simulation, i.e. just solving the fluid flow. All computations are performed with our research code CFS++, which is based on the finite element (FE) method. The presented results show that a pure fluid simulation with prescribed structural movement can substitute the fully-coupled approach. However, caution must be used to ensure accurate boundary conditions on the interface, and we found that only a pressure driven flow correctly responds to the physical effects when using specified motion.

  4. D-VASim: an interactive virtual laboratory environment for the simulation and analysis of genetic circuits. (United States)

    Baig, Hasan; Madsen, Jan


    Simulation and behavioral analysis of genetic circuits is a standard approach of functional verification prior to their physical implementation. Many software tools have been developed to perform in silico analysis for this purpose, but none of them allow users to interact with the model during runtime. The runtime interaction gives the user a feeling of being in the lab performing a real world experiment. In this work, we present a user-friendly software tool named D-VASim (Dynamic Virtual Analyzer and Simulator), which provides a virtual laboratory environment to simulate and analyze the behavior of genetic logic circuit models represented in an SBML (Systems Biology Markup Language). Hence, SBML models developed in other software environments can be analyzed and simulated in D-VASim. D-VASim offers deterministic as well as stochastic simulation; and differs from other software tools by being able to extract and validate the Boolean logic from the SBML model. D-VASim is also capable of analyzing the threshold value and propagation delay of a genetic circuit model. D-VASim is available for Windows and Mac OS and can be downloaded from, © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail:

  5. An iterative method for hydrodynamic interactions in Brownian dynamics simulations of polymer dynamics (United States)

    Miao, Linling; Young, Charles D.; Sing, Charles E.


    Brownian Dynamics (BD) simulations are a standard tool for understanding the dynamics of polymers in and out of equilibrium. Quantitative comparison can be made to rheological measurements of dilute polymer solutions, as well as direct visual observations of fluorescently labeled DNA. The primary computational challenge with BD is the expensive calculation of hydrodynamic interactions (HI), which are necessary to capture physically realistic dynamics. The full HI calculation, performed via a Cholesky decomposition every time step, scales with the length of the polymer as O(N3). This limits the calculation to a few hundred simulated particles. A number of approximations in the literature can lower this scaling to O(N2 - N2.25), and explicit solvent methods scale as O(N); however both incur a significant constant per-time step computational cost. Despite this progress, there remains a need for new or alternative methods of calculating hydrodynamic interactions; large polymer chains or semidilute polymer solutions remain computationally expensive. In this paper, we introduce an alternative method for calculating approximate hydrodynamic interactions. Our method relies on an iterative scheme to establish self-consistency between a hydrodynamic matrix that is averaged over simulation and the hydrodynamic matrix used to run the simulation. Comparison to standard BD simulation and polymer theory results demonstrates that this method quantitatively captures both equilibrium and steady-state dynamics after only a few iterations. The use of an averaged hydrodynamic matrix allows the computationally expensive Brownian noise calculation to be performed infrequently, so that it is no longer the bottleneck of the simulation calculations. We also investigate limitations of this conformational averaging approach in ring polymers.

  6. [Study on the best detector-distance of noninvasive biochemical examination by Monte Carlo simulation]. (United States)

    Dong, Yan-Fei; Lu, Qi-Peng; Ding, Hai-Quan; Gao, Hong-Zhi


    The present paper studies the best detector-distance to improve the near-infrared spectrum signal intensity of the dermis layer and eliminate the interference of the epidermis and subcutaneous layer. First, we analyzed the organizational structure of the skin and calculated the tissue optical parameters of different layers. And we established the Monte Carlo model with the example of glucose absorption peak at 2 270 nm. Then, we used the Monte Carlo method to simulate the light transmission rules in the skin, obtaining the average path length, the average visit depth and the fractions of absorbed energy at each layer with the change in critical angle and detector-distance. The results show that when the photons are incident at an angle less than 45 degrees, you can ignore the effect of the incident angle on photon transmission path, and when the detector-distance is 1 mm, the fraction of absorbed photon energy by the dermis layer is the largest, while it can ensure more energy received by detector. We determined that the best detector-distance is 1mm, which successfully avoids the interference of the epidermis spectral information and obtains large amounts of blood in the dermis layer, which is conducive to the near-infrared non-invasive measurement of biochemical components and the subsequent experiments.

  7. Examination of convective parameterization closures and their scale awareness using cloud-resolving model simulations (United States)

    Ettammal, S.; Zhang, G. J.; Chen, R.


    Closure is the main component of a mass flux-based convective parameterization scheme and it determines the amount of convection under a given large-scale condition. In this study, we use cloud-resolving model output from simulations of both tropical and midlatitude convection to evaluate commonly used closures for a range of global climate model (GCM) horizontal resolutions, taking convective precipitation and mass flux at 600 hPa as measures for deep convection. To mimic different GCM horizontal resolutions, we use high resolution CRM data to create domain averages representing GCM horizontal resolutions of 128 km, 64 km, 32 km, 16 km, 8 km and 4 km. Lead-lag correlation analysis shows that except moisture convergence and turbulent kinetic energy (TKE), none of the other closure variables evaluated in this study show any relationship with convection for the six subdomain sizes. It is found that the correlation between moisture convergence and convective precipitation is largest when moisture convergence leads convection. This correlation weakens as the subdomain size decreases to 8 km or smaller. Although convective precipitation and mass flux increase with moisture convergence, as the subdomain size increases the rate at which they increase becomes smaller. This suggests that moisture convergence-based closure should scale down the predicted mass flux for given moisture convergence as GCM resolution increases. Lead-lag correlation and composite analysis show that TKE is largely a result of convection and therefore its use in a closure variable is not supported.

  8. Education and training of future nuclear engineers through the use of an interactive plant simulator

    Energy Technology Data Exchange (ETDEWEB)

    Ahnert, C.; Cuervo, D.; Garcia-Herranz, N.; Aragones, J.M.; Cabellos, O.; Gallego, E.; Minguez, E.; Lorente, A.; Piedra, D. [Departamento de Ingenieria Nuclear, Universidad Politecnica de Madrid, Jose Gutierrez Abascal 2, 28006 Madrid (Spain); Rebollo, L.; Blanco, J. [Gas Natural-Union FENOSA, Avda. de San Luis 77, 28033 Madrid (Spain)


    The International Atomic Energy Agency (IAEA) sponsors the development of nuclear reactor simulators for education, or arranges the supply of such simulation programs. Aware of this, the Department of Nuclear Engineering of the Universidad Politecnica de Madrid was provided in 2008 with the Interactive Graphical Simulator of the Spanish nuclear power plant Jose Cabrera, whose operation ceased definitively in 2006. According with the IAEA-TECDOC- 1411, the simulator is a Graphical Simulator, used for training of main control room personnel, technical support engineers, and operations management. This paper presents all the work performed at the Department to turn the simulator into a teaching/learning tool, to be use in the nuclear engineering studies following guidance found in: Shtub, A. Parush, T.T. Hewett 'The use of simulation in learning and teaching' (Int. J. Eng. Educ., 25(2), 2009, pp. 206-208). The experience obtained so far with the use of the simulator has been very successful. The graduate students involved in the development of the projects, practices and documents related with the simulator show a great interest for the work that they are doing making that the laboratory where the simulator is installed to be busy place. Regarding the undergraduate students, the practices in the simulator encourage them to follow the Nuclear Energy studies in the Engineering Schools, what is very rewarding for the Department professors. The simulator has proved to be an optimal tool to transfer the knowledge of the physical phenomena that are involved in the nuclear power plants, from the nuclear reactor to the whole set of systems and equipments on a nuclear power plant. It is also a relevant tool for motivation of the students, and to complete the theoretical lessons. This use of the simulator in the learning-teaching process meats also the criteria recommended for the Bologna adapted studies, as it helps to increase the private hands-on work of the

  9. Effect of Interactive River Routing on North Atlantic Overturning in a Simulation of the last Deglaciation (United States)

    Mikolajewicz, Uwe; Ziemen, Florian; Kapsch, Marie; Meccia, Virna


    One of the major challenges in climate modeling is the simulation of glacial-interglacial transitions. A few models of intermediate complexity have been successful in simulating the last termination. Complex atmosphere-ocean general circulation models (AOGCMs) with prescribed ice sheets are able to yield realistic climate changes. Here we present results from our first attempt to simulate a substantial part of the last glacial cycle with an AOGCM coupled interactively with a state-of-the-art ice sheet model. The ECHAM5/MPIOM AOGCM is interactively coupled to the dynamical ice sheet model PISM and the dynamical vegetation model LPJ. The model is integrated from the late Glacial into the Holocene using insolation and greenhouse gas concentrations as transient forcing. To make the long simulations feasible, the atmosphere is accelerated by a factor of 10 relative to the other components using a periodical-synchronous coupling technique. The land sea mask remains fixed at the LGM state. River routing and surface elevation are calculated interactively. A mini-ensemble with different initial conditions is performed. Additionally, one fully synchronously simulation, without acceleration in the atmosphere, is run. In all simulations the northern hemisphere deglaciation starts between 18 and 17 kyr BP, consistent with the onset of global warming. The model produces Heinrich event like variability. These rapid ice discharge events have a strong impact on the North Atlantic meridional overturning circulation (NAMOC). The interactive river routing has a strong impact on the simulated NAMOC during the deglaciation. The retreat of the Laurentide Ice Sheet together with the depressed topography due to the former ice load leads to a redirection of the river routes.. In particular, the discharge route for runoff from the melting southwestern Laurentide shifts from the Gulf of Mexico to the Arctic. The consequence is a rapid reduction/suppression of the North Atlantic deep water

  10. CoFoLaMo: Comparing forest landscape model simulations under different climate, interaction- and land use scenarios (United States)

    Lischke, Heike; Speich, Matthias; Schmatz, Dirk; Vacchiano, Giorgio; Mairota, Paola; Leronni, Vincenzo; Schuler, Laura; Bugmann, Harald; Bruna, Josef; Thom, Dominik; Seidl, Rupert; Reineking, Björn


    Forests play an important role in the global climate system, and are themselves strongly affected by the changing climate. Forest dynamics do not only act at the stand scale, but are also influenced by larger scale drivers, such as landscape management, and by spatial interactions, such as fire spread or seed dispersal. Forest landscape models run on areas larger than a stand and interact spatially and thus are capable of taking into account these effects. We present the setup of the forest landscape model intercomparison CoFoLaMo (which is based on the setup of the ISI-MIP forest stand model comparison), where we examine several forest landscape models- LandClim, ForHyCS, TreeMig, LANDIS II and iLand - in terms of their usefulness for different kinds of applications. We compare the models with respect to their general approach, scales, resolution, and data requirements, processes, interactions, drivers, disturbances, outputs, and uncertainties. We run simulations in different test regions across temperate Europe, e.g., in the northern(Davos)and southern Alps (Valle d'Aosta), the Bavarian Forest and southern Italy (Puglia). Climate drivers (mostly daily T and P) are downscaled to 100 m resolution in the respective regions. For spinup and model testing we use past observed climate, extrapolated back to 1600 AD, for future simulations a set of different RCPs of different model chains from the ISI-MIP community. For model testing we use appropriate spatial forest data available for each region, ranging from NFI data, terrestrial vegetation type maps, or remote sensing derived forest types and high resolution canopy height. To address the landscape aspect of the models, we compare them in different scenarios of spatially interacting disturbances, spatial interactions by seed dispersal and land use.

  11. Leveraging on Easy Java Simulation tool and open source computer simulation library to create interactive digital media for mass customization of high school physics curriculum

    CERN Document Server

    Wee, Loo Kang


    This paper highlights the diverse possibilities in the rich community of educators from the Conceptual Learning of Science (CoLoS) and Open Source Physics (OSP) movement to engage, enable and empower educators and students, to create interactive digital media through computer modeling. This concept revolves around a paradigmatic shift towards participatory learning through immersive computer modeling, as opposed to using technology for information transmission. We aim to engage high school educators to professionally develop themselves by creating and customizing simulations possible through Easy Java Simulation (Ejs) and its learning community. Ejs allows educators to be designers of learning environments through modifying source codes of the simulation. Educators can conduct lessons with students' using these interactive digital simulations and rapidly enhance the simulation through changing the source codes personally. Ejs toolkit, its library of simulations and growing community contributed simulation cod...

  12. Intrinsic and extrinsic motivational orientations in the competitive context: an examination of person-situation interactions. (United States)

    Abuhamdeh, Sami; Csikszentmihalyi, Mihaly


    The current study examined Intrinsic Motivation Orientation and Extrinsic Motivation Orientation (Work Preference Inventory; Amabile, Hill, Hennessey, & Tighe, 1994) as potential trait-level moderators of the way Internet chess players responded to the intrinsic and extrinsic rewards of the chess games they played. On the basis of the defining characteristics of these 2 types of motivational orientations, we predicted that (a) Intrinsic Motivation Orientation would be associated with a stronger curvilinear relationship between challenge and enjoyment and (b) Extrinsic Motivation Orientation would be associated with a heightened affective responsivity to competitive outcome (i.e., winning vs. losing). Results supported the predictions. Implications of the findings are discussed.

  13. Monitoring peptide-surface interaction by means of molecular dynamics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Nonella, Marco, E-mail: [Physikalisch-Chemisches Institut, Universitaet Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland); Seeger, Stefan, E-mail: [Physikalisch-Chemisches Institut, Universitaet Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland)


    Graphical abstract: Protein-surface interactions play a crucial role in a wide field of research areas like biology, biotechnology, or pharmacology. Only recently, it has been shown that not only peptide adsorption represents an important process but also spreading and clustering of adsorbed proteins. By means of classical molecular dynamics, peptide adsorption as well as the dynamics of adsorbed peptides have been investigated in order to gain deeper insight into such processes. The picture shows a snapshot of an adsorbed peptide on a silica surface showing strong direct hydrogen bonding. Research highlights: {yields} Simulation of peptide surface interaction. {yields} Dynamics of hydrogen bond formation and destruction. {yields} Internal flexibility of adsorbed peptides. - Abstract: Protein adsorption and protein surface interactions have become an important research topic in recent years. Very recently, for example, it has been shown that protein clusters can undergo a surface-induced spreading after adsorption. Such phenomena emphasize the need of a more detailed insight into protein-silica interaction at an atomic level. Therefore, we have studied a model system consisting of a short peptide, a silica slab, and water molecules by means of classical molecular dynamics simulations. The study reveals that, besides of electrostatic interactions caused by the chosen charge distribution, the peptide interacts with the silica surface through formation of direct peptide-surface hydrogen bonds as well as indirect peptide-water-surface hydrogen bonds. The number of created hydrogen bonds varies considerably among the simulated structures. The strength of hydrogen bonding determines the mobility of the peptide on the surface and the internal flexibility of the adsorbed peptide.

  14. Two-way coupled fluid structure interaction simulation of a propeller turbine

    Energy Technology Data Exchange (ETDEWEB)

    Schmucker, H [Voith Hydro GmbH and Co. KG, Germany Alexanderstrasse 11, 89522 Heidenheim (Germany); Flemming, F; Coulson, S, E-mail: [Voith Hydro Inc. York, PA, 760 East Berlin Road, York, PA, 17408 (United States)


    During the operation of a hydro turbine the fluid mechanical pressure loading on the turbine blades provides the driving torque on the turbine shaft. This fluid loading results in a structural load on the component which in turn causes the turbine blade to deflect. Classically, these mechanical stresses and deflections are calculated by means of finite element analysis (FEA) which applies the pressure distribution on the blade surface calculated by computational fluid dynamics (CFD) as a major boundary condition. Such an approach can be seen as a oneway coupled simulation of the fluid structure interaction (FSI) problem. In this analysis the reverse influence of the deformation on the fluid is generally neglected. Especially in axial machines the blade deformation can result in a significant impact on the turbine performance. The present paper analyzes this influence by means of fully two-way coupled FSI simulations of a propeller turbine utilizing two different approaches. The configuration has been simulated by coupling the two commercial solvers ANSYS CFX for the fluid mechanical simulation with ANSYS Classic for the structure mechanical simulation. A detailed comparison of the results for various blade stiffness by means of changing Young's Modulus are presented. The influence of the blade deformation on the runner discharge and performance will be discussed and shows for the configuration investigated no significant influence under normal structural conditions. This study also highlights that a two-way coupled fluid structure interaction simulation of a real engineering configuration is still a challenging task for today's commercially available simulation tools.

  15. Examination of a Smallest CELSS (Microcosm) Through an Individual- Based-Model Simulation (United States)

    Ishikawa, Y.; Sugiura, K.

    Research of the effect of space environment on an ecosystem consisting of plants and animals is essential when they are to be positively used in space. Although there have been experiments on various organisms under space environment in the past, they mainly studied the effect of space environment on an individual organism or a single species. Microcosm is drawing attention as an experimental material of an ecosystem consisting of multiple species. The object in this research is to understand the nature of this network system called ecosystem. Thus, a mixed microorganism culturing system consisting of three types of microorganisms (chlorella, bacteria, and rotifer) which form a minimum food chain system as a closed ecosystem was taken for the subject, on which the universal characteristics of ecosystems is searched. From the results of experiments under earth environment, formation of colonies, which is an ecological structure, has been observed at its mature stage. Therefore, formation of colonies in simulation models is important. For example, the Lotka- Volterra model forms a system of the differential equations expressing predator and prey relationship and many numerical calculations have been conducted to various ecosystems based on expanded L-V models. Conventionally, these top-down methods have been used. However, since this method only describes the average concentration of organisms that are distributed uniformly throughout the system and cannot express the spatial structure of the system, it was difficult to express the ecosystem structures like colonies and substance density distribution. In actual ecosystems, there is heterogeneity in the number of individuals and in substance density, and this is thought to have great significance in ecosystems. Consequently, an Individual-Based-Model was used to give rules to predator-prey relationship, suppression, production, self suppression, etc. of each species. It enabled the emergence of the overall system only

  16. 3D Global MHD Simulation of Titan's interaction with its surrounding plasma (United States)

    Ma, Y.; Nagy, A. F.; Toth, G.; Najib, D.; Cravens, T. E.; Crary, F.; Coates, A. J.; Bertucci, C.; Neubauer, F. M.


    The interaction of Titan's ionosphere with its surrounding plasma flow is more complex than analogous solar wind-planet interactions, because of Titan's varying relative location in the Sun-Saturn system. We have studied the role of the angle between the direction of the solar radiation and the corotating plasma flow using our 3D multi-species MHD model. We also present results from a comparison between our model simulations and the observations corresponding to the T9 flyby of Cassini, using the measured upstream plasma parameters.


    Bayer, M. E.


    A hemagglutination-inhibitory mucoprotein from human urine has been studied with the electron microscope. It consists of filaments, with diameters of 40 to > 240 A, composed of smaller fibrils. In the two-dimensional projection of the electron micrographs, the single fibrils often show a zig-zag course with a periodicity of 100 to 140 A; the single branch of a zig-zag measures about 60 A in length and either 20 or 40 A in width. Still thinner fibrillar elements are observable with diameters of 10 A or less. In three-dimensional aspect, the zig-zag structure might be a helix. The fibril-bundle (or filament) reveals a complicated configuration. Heat treatment at 70°C shows some indication of denaturation (e.g. filaments are shorter), whereas at 80°C almost complete degradation of the protein into individual zig-zag elements or smaller pieces is attained. The interaction between influenza virus particles and inhibitory mucoprotein consists of the attachment of a fiber molecule to the virus projections at several sites and frequently on more than one virus particle. PMID:14159029

  18. Examination of a smallest CELSS (microcosm) through an individual-based model simulation (United States)

    Ishikawa, Y.; Yoshida, H.; Kinoshita, M.; Murakami, A.; Sugiura, K.


    Research of the effect of space environment on an ecosystem consisting of plants and animals is essential when they are to be positively used in space. Although there have been experiments on various organisms under space environment in the past, they mainly studied the effect of space environment on an individual organism or a single species. Microcosm is drawing attention as an experimental material of an ecosystem consisting of multiple species. The object in this research is to understand the nature of this network system called ecosystem. Thus, a mixed microorganism culturing system consisting of three types of microorganisms which form a minimum food chain system as a closed ecosystem (chlorella as the producer, bacteria as the decomposer, and rotifer as the consumer) was taken for the subject, on which to research the universal characteristics of ecosystems. From the results of experiments under the terrestrial environment, formation of colonies, which is an ecological structure, has been observed at its mature stage. The organisms form an optimal substance circulation system. Therefore, formation of colonies in simulation models is important. Many attempts have been made to create ecosystem models. For example, the Lotka-Volterra model forms a simultaneous equation with the differential equation expressing predator and prey relationship and many numerical calculations have been conducted on various ecosystems based on expanded L-V models. Conventionally, these top-down methods have been used. However, since this method only describes the average concentration of organisms that are distributed uniformly throughout the system and cannot express the spatial structure of the system, it was difficult to express ecosystem structures like colonies and density distributions. In actual ecosystems, there is heterogeneity in the number of individuals and in substance density, and this is thought to have great significance in ecosystems. Consequently, an individual

  19. Population reversal driven by unrestrained interactions in molecular dynamics simulations: A dialanine model

    Directory of Open Access Journals (Sweden)

    Filippo Pullara


    Full Text Available Standard Molecular Dynamics simulations (MD are usually performed under periodic boundary conditions using the well-established “Ewald summation”. This implies that the distance among each element in a given lattice cell and its corresponding element in another cell, as well as their relative orientations, are constant. Consequently, protein-protein interactions between proteins in different cells—important in many biological activities, such as protein cooperativity and physiological/pathological aggregation—are severely restricted, and features driven by protein-protein interactions are lost. The consequences of these restrictions, although conceptually understood and mentioned in the literature, have not been quantitatively studied before. The effect of protein-protein interactions on the free energy landscape of a model system, dialanine, is presented. This simple system features a free energy diagram with well-separated minima. It is found that, in the case of absence of peptide-peptide (p-p interactions, the ψ = 150° dihedral angle determines the most energetically favored conformation (global free-energy minimum. When strong p-p interactions are induced, the global minimum switches to the ψ = 0° conformation. This shows that the free-energy landscape of an individual molecule is dramatically affected by the presence of other freely interacting molecules of its same type. Results of the study suggest how taking into account p-p interactions in MD allows having a more realistic picture of system activity and functional conformations.

  20. The Atlas of Physiology and Pathophysiology: Web-based multimedia enabled interactive simulations. (United States)

    Kofranek, Jiri; Matousek, Stanislav; Rusz, Jan; Stodulka, Petr; Privitzer, Pavol; Matejak, Marek; Tribula, Martin


    The paper is a presentation of the current state of development for the Atlas of Physiology and Pathophysiology (Atlas). Our main aim is to provide a novel interactive multimedia application that can be used for biomedical education where (a) simulations are combined with tutorials and (b) the presentation layer is simplified while the underlying complexity of the model is retained. The development of the Atlas required the cooperation of many professionals including teachers, system analysts, artists, and programmers. During the design of the Atlas, tools were developed that allow for component-based creation of simulation models, creation of interactive multimedia and their final coordination into a compact unit based on the given design. The Atlas is a freely available online application, which can help to explain the function of individual physiological systems and the causes and symptoms of their disorders. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  1. Numerical simulation of nonlinear long waves interacting with arrays of emergent cylinders

    CERN Document Server

    Zainali, Amir; Weiss, Robert; Irish, Jennifer L; Yang, Yongqian


    We presented numerical simulation of long waves, interacting with arrays of emergent cylinders inside regularly spaced patches, representing discontinues patchy coastal vegetation. We employed the fully nonlinear and weakly dispersive Serre-Green-Naghdi equations (SGN) until the breaking process starts, while we changed the governing equations to nonlinear shallow water equations (NSW) at the vicinity of the breaking-wave peak and during the runup stage. We modeled the cylinders as physical boundaries rather than approximating them as macro-roughness friction. We showed that the cylinders provide protection for the areas behind them. However they might also cause amplification in local water depth in those areas. The presented results are extensively validated against the existing numerical and experimental data. Our results demonstrate the capability and reliability of our model in simulating wave interaction with emergent cylinders.

  2. Advances in Computational Fluid-Structure Interaction and Flow Simulation Conference

    CERN Document Server

    Takizawa, Kenji


    This contributed volume celebrates the work of Tayfun E. Tezduyar on the occasion of his 60th birthday. The articles it contains were born out of the Advances in Computational Fluid-Structure Interaction and Flow Simulation (AFSI 2014) conference, also dedicated to Prof. Tezduyar and held at Waseda University in Tokyo, Japan on March 19-21, 2014. The contributing authors represent a group of international experts in the field who discuss recent trends and new directions in computational fluid dynamics (CFD) and fluid-structure interaction (FSI). Organized into seven distinct parts arranged by thematic topics, the papers included cover basic methods and applications of CFD, flows with moving boundaries and interfaces, phase-field modeling, computer science and high-performance computing (HPC) aspects of flow simulation, mathematical methods, biomedical applications, and FSI. Researchers, practitioners, and advanced graduate students working on CFD, FSI, and related topics will find this collection to be a defi...

  3. An improved simulation routine for modelling coherent high-energy proton interactions with bent crystals

    CERN Document Server

    Forcher, Francesco; Redaelli, Stefano; Zanetti, Marco; CERN. Geneva. ATS Department


    The planes in crystalline solids can constrain the directions that charged particles take as they pass through. Physicists can use this "channelling" property of crystals to steer particle beams. In a bent crystal, for example, channelled particles follow the bend and can change their direction. Several studies are on-going at CERN to verify the possibility of using bent crystals as primary collimators in high energy hadron colliders like the LHC. Simulations have been developed to model the coherent interaction with crystalline planes. The goal of this note is to analyze the data collected on extracted beam from the SPS and develop an improved model to simulate the data’s subtleties, in particular the transition between the volume reflection and amorphous interactions of the beam with crystals.

  4. Dissimilar interaction of CB1/CB2 with lipid bilayers as revealed by molecular dynamics simulation. (United States)

    Ramos, Javier; Cruz, Víctor L; Martínez-Salazar, Javier; Campillo, Nuria E; Páez, Juan A


    Cannabinoid receptors CB1 and CB2 are a striking class of transmembrane proteins involved in a high number of important biological processes. In spite of the inherent similarity (40% in aminoacid sequence) these receptors are found in different cell environments. In addition to this, CB1 activity has been intimately associated with lipid rafts whereas CB2 has not. In this work we have performed a 50 nanosecond molecular dynamics simulation of the inactive conformations of both receptors inserted in a POPC lipid bilayer. Although in both cases the overall protein structure is maintained along the entire simulation we have found important differences in the protein-lipid interaction. While CB1 tends to distort the lipid bilayer regularity, especially in the extracellular moiety, CB2 has a minor influence on the lipid distribution along the plane of the bilayer. This observation is consistent with some experimental facts observed in these cannabinoid receptors with regard to lipid/protein interaction.

  5. Final Report. Coupled simulations of Antarctic Ice-sheet/ocean interactions using POP and CISM

    Energy Technology Data Exchange (ETDEWEB)

    Asay-Davis, Xylar Storm [Potsdam Institute for Climate Impact Research, Potdam (Germany)


    The project performed under this award, referred to from here on as CLARION (CoupLed simulations of Antarctic Ice-sheet/Ocean iNteractions), included important advances in two models of ice sheet and ocean interactions. Despite its short duration (one year), the project made significant progress on its three major foci. First, together with collaborator Daniel Martin at Lawrence Berkeley National Laboratory (LBNL), I developed the POPSICLES coupled ice sheet-ocean model to the point where it could perform a number of pan-Antarctic simulations under various forcing conditions. The results were presented at a number of major conferences and workshops worldwide, and are currently being incorporated into two manuscripts in preparation.

  6. GPU-accelerated simulation of colloidal suspensions with direct hydrodynamic interactions (United States)

    Kopp, M.; Höfling, F.


    Solvent-mediated hydrodynamic interactions between colloidal particles can significantly alter their dynamics. We discuss the implementation of Stokesian dynamics in leading approximation for streaming processors as provided by the compute unified device architecture (CUDA) of recent graphics processors (GPUs). Thereby, the simulation of explicit solvent particles is avoided and hydrodynamic interactions can easily be accounted for in already available, highly accelerated molecular dynamics simulations. Special emphasis is put on efficient memory access and numerical stability. The algorithm is applied to the periodic sedimentation of a cluster of four suspended particles. Finally, we investigate the runtime performance of generic memory access patterns of complexity O( N 2) for various GPU algorithms relying on either hardware cache or shared memory.

  7. Molecular spectroscopic studies examining the interactions between phenobarbital and human serum albumin in alcohol consumption. (United States)

    Cui, Sheng-Feng; Li, Wei; Zhou, Cheng-He


    Alcohol dependence is associated with a wide range of serious mental, physical, and social consequences and is one of the most common chronic diseases worldwide. Barbiturates, which are a first-line treatment in the clinic for alcohol withdrawal, may result in combined barbiturate and alcohol use. Their co-use abuse may promote synergistic effects between barbiturates and alcohol in vivo. To investigate the effects of different alcohol concentrations on the synergistic effects of phenobarbital and alcohol. The interactions between phenobarbital and human serum albumin (HSA) and the effects of different alcohol concentrations on the binding behaviors of the phenobarbital-HSA system were investigated by molecular docking and spectroscopic methods, including fluorescence spectroscopy and UV-visible absorption spectroscopy. Experimental results revealed that phenobarbital can be stored and carried by HSA. The presence of alcohol (≤1.96 × 10(-2) M) can increase the proportion of free phenobarbital and shorten the half-life and storage time of phenobarbital in the blood, thereby enhancing its bioactive efficacy. The binding constants (Kb) of the phenobarbital-HSA system decrease in the presence of alcohol (≥2.61 × 10(-2) M), which suggests that phenobarbital should be quickly cleared from blood, thereby decreasing the activity of phenobarbital. The effects of alcohol on the transposition of phenobarbital by HSA at the beginning of the barbiturate metabolic process play an important role in the synergistic effects of phenobarbital and alcohol. This mechanism may be significant for the clinical dosage of patients with alcohol dependence.

  8. Local Interaction Simulation Approach for Fault Detection in Medical Ultrasonic Transducers

    Directory of Open Access Journals (Sweden)

    Z. Hashemiyan


    Full Text Available A new approach is proposed for modelling medical ultrasonic transducers operating in air. The method is based on finite elements and the local interaction simulation approach. The latter leads to significant reductions of computational costs. Transmission and reception properties of the transducer are analysed using in-air reverberation patterns. The proposed approach can help to provide earlier detection of transducer faults and their identification, reducing the risk of misdiagnosis due to poor image quality.

  9. Using the design of simulation experiments to failures interactive effects analysis in process: a hypothetical case


    Fabiano Leal; Dagoberto Alves De Almeida; José Arnaldo Barra Montevechi; Fernando Augusto Silva Marins


    This work presents a failures interactive effects analysis in a process, by means ofsimulations experiments. The chosen process is a hypothetical system, simulated throughsoftware Promodel®. Two conceptual models are generated, representing the system(mapping process) and the failures considered in system (Fault Tree Analysis). Theseconceptual models are translated in a computerized model, for the analysis of individual andcombined effects on the variable “number of produced pieces”. This exp...

  10. Two Methods For Simulating the Strong-Strong Beam-Beam Interaction in Hadron Colliders

    Energy Technology Data Exchange (ETDEWEB)

    Warnock, Robert L.


    We present and compare the method of weighted macro particle tracking and the Perron-Frobenius operator technique for simulating the time evolution of two beams coupled via the collective beam-beam interaction in 2-D and 4-D (transverse) phase space. The coherent dipole modes, with and without lattice nonlinearities and external excitation, are studied by means of the Vlasov-Poisson system.

  11. Dynamic simulation of concentrated macromolecular solutions with screened long-range hydrodynamic interactions: algorithm and limitations. (United States)

    Ando, Tadashi; Chow, Edmond; Skolnick, Jeffrey


    Hydrodynamic interactions exert a critical effect on the dynamics of macromolecules. As the concentration of macromolecules increases, by analogy to the behavior of semidilute polymer solutions or the flow in porous media, one might expect hydrodynamic screening to occur. Hydrodynamic screening would have implications both for the understanding of macromolecular dynamics as well as practical implications for the simulation of concentrated macromolecular solutions, e.g., in cells. Stokesian dynamics (SD) is one of the most accurate methods for simulating the motions of N particles suspended in a viscous fluid at low Reynolds number, in that it considers both far-field and near-field hydrodynamic interactions. This algorithm traditionally involves an O(N(3)) operation to compute Brownian forces at each time step, although asymptotically faster but more complex SD methods are now available. Motivated by the idea of hydrodynamic screening, the far-field part of the hydrodynamic matrix in SD may be approximated by a diagonal matrix, which is equivalent to assuming that long range hydrodynamic interactions are completely screened. This approximation allows sparse matrix methods to be used, which can reduce the apparent computational scaling to O(N). Previously there were several simulation studies using this approximation for monodisperse suspensions. Here, we employ newly designed preconditioned iterative methods for both the computation of Brownian forces and the solution of linear systems, and consider the validity of this approximation in polydisperse suspensions. We evaluate the accuracy of the diagonal approximation method using an intracellular-like suspension. The diffusivities of particles obtained with this approximation are close to those with the original method. However, this approximation underestimates intermolecular correlated motions, which is a trade-off between accuracy and computing efficiency. The new method makes it possible to perform large

  12. Interactive simulator for e-Learning environments: a teaching software for health care professionals. (United States)

    De Lazzari, Claudio; Genuini, Igino; Pisanelli, Domenico M; D'Ambrosi, Alessandra; Fedele, Francesco


    There is an established tradition of cardiovascular simulation tools, but the application of this kind of technology in the e-Learning arena is a novel approach. This paper presents an e-Learning environment aimed at teaching the interaction of cardiovascular and lung systems to health-care professionals. Heart-lung interaction must be analyzed while assisting patients with severe respiratory problems or with heart failure in intensive care unit. Such patients can be assisted by mechanical ventilatory assistance or by thoracic artificial lung."In silico" cardiovascular simulator was experimented during a training course given to graduate students of the School of Specialization in Cardiology at 'Sapienza' University in Rome.The training course employed CARDIOSIM©: a numerical simulator of the cardiovascular system. Such simulator is able to reproduce pathophysiological conditions of patients affected by cardiovascular and/or lung disease. In order to study the interactions among the cardiovascular system, the natural lung and the thoracic artificial lung (TAL), the numerical model of this device has been implemented. After having reproduced a patient's pathological condition, TAL model was applied in parallel and hybrid model during the training course.Results obtained during the training course show that TAL parallel assistance reduces right ventricular end systolic (diastolic) volume, but increases left ventricular end systolic (diastolic) volume. The percentage changes induced by hybrid TAL assistance on haemodynamic variables are lower than those produced by parallel assistance. Only in the case of the mean pulmonary arterial pressure, there is a percentage reduction which, in case of hybrid assistance, is greater (about 40%) than in case of parallel assistance (20-30%).At the end of the course, a short questionnaire was submitted to students in order to assess the quality of the course. The feedback obtained was positive, showing good results with respect to


    Directory of Open Access Journals (Sweden)

    Natalya Vladislavovna Manyukova


    Full Text Available Purpose. The article is devoted to FSES IN the 3rd generation demands the use of interactive forms of learning. The subject of analysis are the ways of activization of cognitive activity of students. The authors set themselves the goal of selecting the best forms and means of organization of educational process in the University. Methodology. The study will form the literature review, simulation, observation and experiment. Results. The results of this work are that the authors reveal characteristics and components of the method of computer simulation. Based on the analysis of the practical application of this method was formulated the necessary stages for its implementation at the training session. As one of the instruments of implementation of the method of computer simulation, the authors consider the MS Excel program. The article provides concrete examples of using spreadsheets for computer modeling. Practical implications. The results of the study can be used in teaching different disciplines.

  14. Fluid-structure interaction computations for geometrically resolved rotor simulations using CFD

    DEFF Research Database (Denmark)

    Heinz, Joachim Christian; Sørensen, Niels N.; Zahle, Frederik


    still shows good agreements in the predicted structural responses of HAWC2 and HAWC2CFD since the differences in the computed force signals only persist for an insignificantly short time span. The considerable new capabilities of HAWC2CFD are finally demonstrated by simulating vortex-induced vibrations......This paper presents a newly developed high-fidelity fluid–structure interaction simulation tool for geometrically resolved rotor simulations of wind turbines. The tool consists of a partitioned coupling between the structural part of the aero-elastic solver HAWC2 and the finite volume computational...... fluid dynamics (CFD) solver EllipSys3D. The paper shows that the implemented loose coupling scheme, despite a non-conservative force transfer, maintains a sufficient numerical stability and a second-order time accuracy. The use of a strong coupling is found to be redundant. In a first test case...

  15. Simulation of the beam halo from the beam-beam interaction in LEP

    Energy Technology Data Exchange (ETDEWEB)

    Chen, T.; Irwin, J.; Siemann, R.


    The luminosity lifetimes of e{sup +}e{sup {minus}} colliders are often dominated by the halo produced by the beam-beam interaction. They have developed a simulation technique to model this halo using the flux across boundaries in amplitude space to decrease the CPU time by a factor of one-hundred or more over `brute force` tracking. It allows simulation of density distributions and halos corresponding to realistic lifetimes. Reference 1 shows the agreement with brute force tracking in a number of cases and the importance of beam-beam resonances in determining the density distribution of large amplitudes. this research is now directed towards comparisons with operating colliders and studies of the combined effects of lattice and beam-beam nonlinearities. LEP offers an ideal opportunity for both, and in this paper they are presenting the first results of LEP simulations.

  16. Characterization of the Interaction between Gallic Acid and Lysozyme by Molecular Dynamics Simulation and Optical Spectroscopy

    Directory of Open Access Journals (Sweden)

    Minzhong Zhan


    Full Text Available The binding interaction between gallic acid (GA and lysozyme (LYS was investigated and compared by molecular dynamics (MD simulation and spectral techniques. The results from spectroscopy indicate that GA binds to LYS to generate a static complex. The binding constants and thermodynamic parameters were calculated. MD simulation revealed that the main driving forces for GA binding to LYS are hydrogen bonding and hydrophobic interactions. The root-mean-square deviation verified that GA and LYS bind to form a stable complex, while the root-mean-square fluctuation results showed that the stability of the GA-LYS complex at 298 K was higher than that at 310 K. The calculated free binding energies from the molecular mechanics/Poisson-Boltzmann surface area method showed that van der Waals forces and electrostatic interactions are the predominant intermolecular forces. The MD simulation was consistent with the spectral experiments. This study provides a reference for future study of the pharmacological mechanism of GA.

  17. Hydroacoustic simulation of rotor-stator interaction in resonance conditions in Francis pump-turbine

    Energy Technology Data Exchange (ETDEWEB)

    Nicolet, C [Power Vision Engineering sarl, Ch. des Champs-Courbes 1, CH-1024 Ecublens (Switzerland); Ruchonnet, N; Alligne, S; Avellan, F [EPFL Laboratory for Hydraulic Machines, Av. de Cour 33bis, CH-1007 Lausanne (Switzerland); Koutnik, J, E-mail: christophe.nicolet@powervision-eng.c [Voith Hydro Holding GmbH and Co. KG, Alexanderstr. 11, 89522 Heidenheim (Germany)


    Combined effect of rotating pressure field related to runner blade and wakes of wicket gates leads to rotor stator interactions, RSI, in Francis pump-turbines. These interactions induce pressures waves propagating in the entire hydraulic machine. Superposition of those pressure waves may result in standing wave in the spiral casing and rotating diametrical mode in the guide vanes and can cause strong pressure fluctuations and vibrations. This paper presents the modeling, simulation and analysis of Rotor-Stator Interaction of a scale model of a Francis pump-turbine and related test rig using a one-dimensional approach. The hydroacoustic modeling of the Francis pump-turbine takes into account the spiral casing, the 20 guide vanes, the 9 rotating runner vanes. The connection between stationary and rotating parts is ensured by a valve network driven according to the unsteady flow distribution between guide vanes and runner vanes. Time domain simulations are performed for 2 different runner rotational speeds in turbine mode. The simulation results are analyzed in frequency domain and highlights hydroacoustic resonance between RSI excitations and the spiral case. Rotating diametrical mode in the vaneless gap and standing wave in the spiral case are identified. The influence of the resonance on phase and amplitude of pressure fluctuations obtained for both the spiral case and the vaneless gap is analyzed. The mode shape and frequencies are confirmed using eigenvalues analysis.

  18. A comparison of numerical simulations and analytical theory of the dynamics of interacting magnetic vortices

    Energy Technology Data Exchange (ETDEWEB)

    Asmat-Uceda, Martin; Buchanan, Kristen S., E-mail: [Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States); Cheng, Xuemei; Wang, Xiao [Department of Physics, Bryn Mawr College, Bryn Mawr, Pennsylvania 19010 (United States); Clarke, David J. [Department of Physics, California Institute of Technology, Pasadena, California 91125 (United States); Tchernyshyov, Oleg [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 20723 (United States)


    Magnetostatic interactions between vortices in closely spaced planar structures are important for applications including vortex-based magnonic crystals and spin torque oscillator networks. Analytical theories that include magnetostatic interaction effects have been proposed but have not yet been rigorously tested. Here, we compare micromagnetic simulations of the dynamics of magnetic vortices confined in three disks in an equilateral triangle configuration to analytical theories that include coupling. Micromagnetic simulations show that the magnetostatic coupling between the disks leads to splitting of the gyrotropic resonance into three modes and that the frequency splitting increases with decreasing separation. The temporal profiles of the magnetization depend on the vortex polarities and chiralities; however, the frequencies depend only on the polarity combinations and will fall into one of two categories: all polarities equal or one polarity opposite to the others, where the latter leads to a larger frequency splitting. Although the magnitude of the splitting observed in the simulations is larger than what is expected based on purely dipolar interactions, a simple analytical model that assumes dipole-dipole coupling captures the functional form of the frequency splitting and the motion patterns just as well as more complex models.

  19. Molecular Dynamics Simulation of Barnase: Contribution of Noncovalent Intramolecular Interaction to Thermostability

    Directory of Open Access Journals (Sweden)

    Zhiguo Chen


    Full Text Available Bacillus amyloliquefaciens ribonuclease Barnase (RNase Ba is a 12 kD (kilodalton small extracellular ribonuclease. It has broad application prospects in agriculture, clinical medicine, pharmaceutical, and so forth. In this work, the thermal stability of Barnase has been studied using molecular dynamics simulation at different temperatures. The present study focuses on the contribution of noncovalent intramolecular interaction to protein stability and how they affect the thermal stability of the enzyme. Profiles of root mean square deviation and root mean square fluctuation identify thermostable and thermosensitive regions of Barnase. Analyses of trajectories in terms of secondary structure content, intramolecular hydrogen bonds and salt bridge interactions indicate distinct differences in different temperature simulations. In the simulations, Four three-member salt bridge networks (Asp8-Arg110-Asp12, Arg83-Asp75-Arg87, Lys66-Asp93-Arg69, and Asp54-Lys27-Glu73 have been identified as critical salt bridges for thermostability which are maintained stably at higher temperature enhancing stability of three hydrophobic cores. The study may help enlighten our knowledge of protein structural properties, noncovalent interactions which can stabilize secondary peptide structures or promote folding, and also help understand their actions better. Such an understanding is required for designing efficient enzymes with characteristics for particular applications at desired working temperatures.

  20. A multilevel cross-cultural examination of role overload and organizational commitment: investigating the interactive effects of context. (United States)

    Fisher, David M


    Considering the influential nature of context, the current investigation examined whether the relationship between role overload and organizational commitment was affected by various contextual factors. Drawing on the occupational stress literature, structural empowerment and cooperative climate were examined as factors that would mitigate the negative effects of role overload on organizational commitment. In addition, national culture was examined to determine whether empowerment and cooperative climate had consistent moderating effects across cultures. The relationships among these variables were examined using hierarchical linear modeling in a sample of 6,264 employees working at a multinational organization in 337 different work locations across 18 countries. Results suggested that the negative effect of role overload on organizational commitment did not vary as a function of culture in the current sample, but empowerment and cooperative climate had a moderating influence on this relationship. Furthermore, a 3-way interaction was observed between the cultural variable of power distance, empowerment, and role overload in predicting organizational commitment, suggesting that factors that serve to mitigate the negative effects of role overload in one culture may be ineffectual in another. This 3-way interaction was observed regardless of whether Hofstede's (2001) cultural value indices were used or the cultural practice scores from the Global Leadership and Organizational Behavior Effectiveness (GLOBE) project (R. J. House, Hanges, Javidan, Dorfman, & Gupta, 2004).

  1. Examining the single and interactive effects of three insecticides on amphibian metamorphosis. (United States)

    Boone, Michelle D


    Although aquatic communities frequently are exposed to a number of pesticides, the effects of chemical mixtures are not well understood. In two separate studies, I examined how insecticide mixtures influenced the likelihood of unpredictable, nonadditive effects on American toad (Bufo americanus) and green frog (Rana clamitans) tadpoles reared in outdoor aquatic communities. I exposed tadpoles to single or multiple insecticides at approximately half the reported median lethal concentrations using insecticides that were either acetylcholinesterase inhibitors (carbaryl or malathion) or a sodium-channel disruptor (permethrin). I found that combinations of insecticides with the same mode of action were more likely to have nonadditive effects on amphibian metamorphosis compared with those having different modes of action. Additionally, in one study, a commercial formulation of permethrin led to near-complete elimination of American toads, suggesting that this formulation could have adverse effects on aquatic communities. Many community studies exploring the ecological effects of expected environmental concentrations of pesticides have suggested that indirect effects in the food web, rather than direct effects on individual physiology, have the largest effect on amphibians. The present study indicates that direct effects of pesticides may become particularly important when insecticides with the same mode of action are present in the environment.

  2. The Basic Immune Simulator: An agent-based model to study the interactions between innate and adaptive immunity

    Directory of Open Access Journals (Sweden)

    Orosz Charles G


    Full Text Available Abstract Background We introduce the Basic Immune Simulator (BIS, an agent-based model created to study the interactions between the cells of the innate and adaptive immune system. Innate immunity, the initial host response to a pathogen, generally precedes adaptive immunity, which generates immune memory for an antigen. The BIS simulates basic cell types, mediators and antibodies, and consists of three virtual spaces representing parenchymal tissue, secondary lymphoid tissue and the lymphatic/humoral circulation. The BIS includes a Graphical User Interface (GUI to facilitate its use as an educational and research tool. Results The BIS was used to qualitatively examine the innate and adaptive interactions of the immune response to a viral infection. Calibration was accomplished via a parameter sweep of initial agent population size, and comparison of simulation patterns to those reported in the basic science literature. The BIS demonstrated that the degree of the initial innate response was a crucial determinant for an appropriate adaptive response. Deficiency or excess in innate immunity resulted in excessive proliferation of adaptive immune cells. Deficiency in any of the immune system components increased the probability of failure to clear the simulated viral infection. Conclusion The behavior of the BIS matches both normal and pathological behavior patterns in a generic viral infection scenario. Thus, the BIS effectively translates mechanistic cellular and molecular knowledge regarding the innate and adaptive immune response and reproduces the immune system's complex behavioral patterns. The BIS can be used both as an educational tool to demonstrate the emergence of these patterns and as a research tool to systematically identify potential targets for more effective treatment strategies for diseases processes including hypersensitivity reactions (allergies, asthma, autoimmunity and cancer. We believe that the BIS can be a useful addition to

  3. Simulation of water-rock interaction in the Yellowstone geothermal system using TOUGHREACT

    Energy Technology Data Exchange (ETDEWEB)

    Dobson, Patrick F.; Salah, Sonia; Spycher, Nicolas; Sonnenthal, Eric L.


    The Yellowstone geothermal system provides an ideal opportunity to test the ability of reactive transport models to simulate the chemical and hydrological effects of water-rock interaction. Previous studies of the Yellowstone geothermal system have characterized water-rock interaction through analysis of rocks and fluids obtained from both surface and downhole samples. Fluid chemistry, rock mineralogy, permeability, porosity, and thermal data obtained from the Y-8 borehole in Upper Geyser Basin were used to constrain a series of reactive transport simulations of the Yellowstone geothermal system using TOUGHREACT. Three distinct stratigraphic units were encountered in the 153.4 m deep Y-8 drill core: volcaniclastic sandstone, perlitic rhyolitic lava, and nonwelded pumiceous tuff. The main alteration phases identified in the Y-8 core samples include clay minerals, zeolites, silica polymorphs, adularia, and calcite. Temperatures observed in the Y-8 borehole increase with depth from sub-boiling conditions at the surface to a maximum of 169.8 C at a depth of 104.1 m, with near-isothermal conditions persisting down to the well bottom. 1-D models of the Y-8 core hole were constructed to simulate the observed alteration mineral assemblage given the initial rock mineralogy and observed fluid chemistry and temperatures. Preliminary simulations involving the perlitic rhyolitic lava unit are consistent with the observed alteration of rhyolitic glass to form celadonite.

  4. Towards Online Visualization and Interactive Monitoring of Real-Time CFD Simulations on Commodity Hardware

    Directory of Open Access Journals (Sweden)

    Nils Koliha


    Full Text Available Real-time rendering in the realm of computational fluid dynamics (CFD in particular and scientific high performance computing (HPC in general is a comparably young field of research, as the complexity of most problems with practical relevance is too high for a real-time numerical simulation. However, recent advances in HPC and the development of very efficient numerical techniques allow running first optimized numerical simulations in or near real-time, which in return requires integrated and optimized visualization techniques that do not affect performance. In this contribution, we present concepts, implementation details and several application examples of a minimally-invasive, efficient visualization tool for the interactive monitoring of 2D and 3D turbulent flow simulations on commodity hardware. The numerical simulations are conducted with ELBE, an efficient lattice Boltzmann environment based on NVIDIA CUDA (Compute Unified Device Architecture, which provides optimized numerical kernels for 2D and 3D computational fluid dynamics with fluid-structure interactions and turbulence.

  5. Multi-dimensional simulation package for ultrashort pulse laser-matter interactions (United States)

    Suslova, Anastassiya; Hassanein, Ahmed


    Advanced simulation models recently became a popular tool of investigation of ultrashort pulse lasers (USPLs) to enhance understanding of the physics and allow minimizing the experimental costs for optimization of laser and target parameters for various applications. Our research interest is focused on developing multi-dimensional simulation package FEMTO-2D to investigate the USPL-matter interactions and laser induced effects. The package is based on solution of two heat conduction equations for electron and lattice sub-systems - enhanced two temperature model (TTM). We have implemented theoretical approach based on the collision theory to define the thermal dependence of target material optical properties and thermodynamic parameters. Our approach allowed elimination of fitted parameters commonly used in TTM based simulations. FEMTO-2D is used to simulated the light absorption and interactions for several metallic targets as a function of wavelength and pulse duration for wide range of laser intensity. The package has capability to consider different angles of incidence and polarization. It has also been used to investigate the damage threshold of the gold coated optical components with the focus on the role of the film thickness and substrate heat sink effect. This work was supported by the NSF, PIRE project.

  6. Simulating Molecular Interactions of Carbon Nanoparticles with a Double-Stranded DNA Fragment

    Directory of Open Access Journals (Sweden)

    Zhuang Wang


    Full Text Available Molecular interactions between carbon nanoparticles (CNPs and a double-stranded deoxyribonucleic acid (dsDNA fragment were investigated using molecular dynamics (MD simulations. Six types of CNPs including fullerenes (C60 and C70, (8,0 single-walled carbon nanotube (SWNT, (8,0 double-walled carbon nanotube (DWNT, graphene quantum dot (GQD, and graphene oxide quantum dot (GOQD were studied. Analysis of the best geometry indicates that the dsDNA fragment can bind to CNPs through pi-stacking and T-shape. Moreover, C60, DWNT, and GOQD bind to the dsDNA molecules at the minor groove of the nucleotide, and C70, SWNT, and GQD bind to the dsDNA molecules at the hydrophobic ends. Estimated interaction energy implies that van der Waals force may mainly contribute to the mechanisms for the dsDNA-C60, dsDNA-C70, and dsDNA-SWNT interactions and electrostatic force may contribute considerably to the dsDNA-DWNT, dsDNA-GQD, and dsDNA-GOQD interactions. On the basis of the results from large-scale MD simulations, it was found that the presence of the dsDNA enhances the dispersion of C60, C70, and SWNT in water and has a slight impact on DWNT, GQD, and GOQD.

  7. A combined experimental and molecular simulation study of factors influencing interaction of quinoa proteins-carrageenan. (United States)

    Montellano Duran, Natalia; Spelzini, Darío; Wayllace, Natael; Boeris, Valeria; Barroso da Silva, Fernando L


    The interaction between quinoa proteins isolate (QP isolate) and the negatively charged polysaccharide ι-Carragennan (Carr) as a function of pH was studied. Experimental measurements as turbidity, hydrophobic surface, ζ-potential, and hydrodynamic size were carried out. Associative interaction between QP and Carr was found in the pH range between 1 and 2.9. When both molecules are negatively charged (pH>5,5), a pure Coulombic repulsion regime is observed and the self-association of QP due to the Carr exclusion is proposed. In the intermediate pH range, the experimental data suggests that the charge regulation mechanism can overcome the electrostatic repulsion that may take place (and an attraction between QP and Carr can still be observed). Computational simulations by means of free energy derivatives using the Monte Carlo method were carried out to better understand the interaction mechanism between QP and Carr. QP was modeled as a single protein using one of the major proteins, Chenopodin (Ch), and Carr was modeled as a negatively charged polyelectrolyte (NCP) chain, both in the cell model framework. Simulation results showed attractive interactions in agreement with the experimental data. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Impact of interactive chemistry of stratospheric ozone on Southern Hemisphere paleoclimate simulation (United States)

    Noda, Satoshi; Kodera, Kunihiko; Adachi, Yukimasa; Deushi, Makoto; Kitoh, Akio; Mizuta, Ryo; Murakami, Shigenori; Yoshida, Kohei; Yoden, Shigeo


    A series of numerical simulations of the mid-Holocene (6 kyr B.P.) climate are performed by using an Earth System Model of the Meteorological Research Institute of the Japan Meteorological Agency to investigate the impact of stratospheric ozone distribution, which is modulated by the change in orbital elements of the Earth, on the surface climate. The results of interactive ozone chemistry calculations for the mid-Holocene and preindustrial periods are compared with those of the corresponding experiments in the fifth Coupled Model Intercomparison Project (CMIP5), in which the ozone distribution was prescribed to the 1850 Common Era level. The contribution of the interactive ozone chemistry in a quasi-equilibrium state reveals a significant anomaly of up to +1.7 K in the Antarctic region for the annual mean zonal mean surface air temperature. This impact on the surface climate is explained by a similar mechanism to the cooling influence of the Antarctic ozone hole but opposite in sign: Weakening of the westerly jet associated with the Southern Annular Mode provides weakening of equatorward ocean surface current, sea ice retreat, and then warm sea surface temperature and surface air temperature. All the mid-Holocene runs by CMIP5 models with the prescribed ozone had cold bias in sea surface temperature when compared with geological proxy data, whereas the bias is reduced in our simulations by using interactive ozone chemistry. We recommend that climate models include interactive sea ice and ozone distribution that are consistent with paleosolar insolation.

  9. Modeling multiple communities of interest for interactive simulation and gaming: the dynamic adversarial gaming algorithm project (United States)

    Santos, Eugene, Jr.; Zhao, Qunhua; Pratto, Felicia; Pearson, Adam R.; McQueary, Bruce; Breeden, Andy; Krause, Lee


    Nowadays, there is an increasing demand for the military to conduct operations that are beyond traditional warfare. In these operations, analyzing and understanding those who are involved in the situation, how they are going to behave, and why they behave in certain ways is critical for success. The challenge lies in that behavior does not simply follow universal/fixed doctrines; it is significantly influenced by soft factors (i.e. cultural factors, societal norms, etc.). In addition, there is rarely just one isolated enemy; the behaviors and responses of all groups in the region, and the dynamics of the interaction among them composes an important part of the whole picture. The Dynamic Adversarial Gaming Algorithm (DAGA) project aims to provide a wargaming environment for automation of simulating dynamics of geopolitical crisis and eventually be applied to military simulation and training domain, and/or commercial gaming arena. The focus of DAGA is on modeling communities of interest (COIs), where various individuals, groups, and organizations as well as their interactions are captured. The framework should provide a context for COIs to interact with each other and influence others' behaviors. These behaviors must incorporate soft factors by modeling cultural knowledge. We do so by representing cultural variables and their influence on behavior using probabilistic networks. In this paper, we describe our COI modeling, the development of cultural networks, the interaction architecture, and a prototype of DAGA.

  10. Numerical simulation of the interaction of elements of active protection with metal barriers (United States)

    Radchenko, P. A.; Batuev, S. P.; Radchenko, A. V.


    The present paper is aimed at working out the algorithm of multi-contact interaction of solid bodies; it studies the influence of the shape of projectile (damage agent) on its penetration capability. Steel projectiles of different shape have been considered as damage agents: sphere, regular tetrahedron, cube, cylinder and plate. The weight of projectiles has been kept the same. Antitank grenade has been used as a target. The study has been conducted by means of numerical simulation using finite element analysis. The simulation is three-dimensional. Behavior of materials has been described by elasto-plastic model taking into consideration the fracture and fragmentation of interacting bodies. The speed of interaction has been considered within the range of 800 to 2000 m/s. Research results demonstrated significant influence of the projectile shape on its penetration capability. Projectile in the shape of elongated cylinder has shown better penetration capability. Considering the weight of damage agents (except for sphere and plate) their maximum penetration capability has been reached at the speed of 1400 m/s. Increase of the speed of interaction has been followed by intensive fracture of damage agents and their penetration capability thus has worsened.

  11. Large Eddy simulations of flame/acoustics interactions in a swirl flow; Simulation aux grandes echelles des interactions flamme / acoustique dans un ecoulement vrille

    Energy Technology Data Exchange (ETDEWEB)

    Selle, L.


    Swirl flows exhibit a large variety of topologies, depending on the ratio of the flux axial momentum to the axial flux of tangential momentum: this ratio is called swirl number. Above a given critical value for the swirl number, the pressure gradient reverses the flow on the axis of rotation. This central recirculation zone is used in turbines for flame stabilization. And yet, reacting-swirled flows can exhibit combustion instabilities resulting from the coupling between acoustics and unsteady heat release. Combustion instabilities can lead to loss of control or even complete destruction of the system. Their prediction is impossible with standard engineering tools. The work presented here investigates the capabilities of numerical research tools for the prediction of combustion instabilities. Large-Eddy Simulation (LES) is implemented in a code solving the Navier-Stokes equations for compressible-multi-components fluids (code AVBP developed at CERFACS). This method takes into account for the major ingredients of combustion instabilities such as acoustics and flame / vortex interaction. The LES methodology is validated in the swirled flow from a complex industrial burner (SIEMENS PG). Both reactive and non-reactive regimes are successfully compared with experimental data in terms of mean temperature and mean and RMS velocities. Experimental measurements were performed at the university of Karlsruhe (Germany). A detailed analysis of the acoustics and its interaction with the flame front is performed with the code AVSP, also developed at CERFACS. (author)

  12. Aacsfi-PSC. Advanced accelerator concepts for strong field interaction simulated with the Plasma-Simulation-Code

    Energy Technology Data Exchange (ETDEWEB)

    Ruhl, Hartmut [Munich Univ. (Germany). Chair for Computational and Plasma Physics


    Since the installation of SuperMUC phase 2 the 9216 nodes of phase 1 are more easily available for large scale runs allowing for the thin foil and AWAKE simulations. Besides phase 2 could be used in parallel for high throughput of the ion acceleration simulations. Challenging to our project were the full-volume checkpoints required by PIC that strained the I/O-subsystem of SuperMUC to its limits. New approaches considered for the next generation system, like burst buffers could overcome this bottleneck. Additionally, as the FDTD solver in PIC is strongly bandwidth bound, PSC will benefit profoundly from high-bandwidth memory (HBM) that most likely will be available in future HPC machines. This will be of great advantage as in 2018 phase II of AWAKE should begin, with a longer plasma channel further increasing the need for additional computing resources. Last but not least, it is expected that our methods used in plasma physics (many body interaction with radiation) will be more and more adapted for medical diagnostics and treatments. For this research field we expect centimeter sized volumes with necessary resolutions of tens of micro meters resulting in boxes of >10{sup 12} voxels (100-200 TB) on a regular basis. In consequence the demand for computing time and especially for data storage and data handling capacities will also increase significantly.

  13. Research on distribution equipment training system based on holographic projection interactive simulation technology (United States)

    Ma, Meng-Chao; Zhang, Yan; Li, Guang-Lei; Gao, Nan-Nan; Huang, Jin-Xin; Ma, Zhi-Guang; Shang, Ling-Ling; Guo, Liang-Feng


    This paper presents a three-dimensional (3D) interactive simulation training system based on holographic projection technology, nano-touch technology and interactive training mode, which realize the 3D display without stereoscopic glasses and touch type human computer interaction. 4 sets of holographic training courseware and 2 sets of fault presentation courseware was developed. Every courseware includes four parts: the cognition mode, the operation mode, the disassembling mode and daily maintenance mode. The system can carry out the training course of distribution automation equipment structure, disassembling and assembling, daily maintenance, operation, and the fault handling. A new training mode of power equipment training was created, which opened a new era of power equipment training.

  14. Statistical analysis of nonlinear wave interactions in simulated Langmuir turbulence data

    Directory of Open Access Journals (Sweden)

    J. Soucek


    Full Text Available We present a statistical analysis of strong turbulence of Langmuir and ion-sound waves resulting from beam-plasma interaction. The analysis is carried out on data sets produced by a numerical simulation of one-dimensional Zakharov’s equations. The nonlinear wave interactions are studied using two different approaches: high-order spectra and Volterra models. These methods were applied to identify two and three wave processes in the data, and the Volterra model was furthermore employed to evaluate the direction and magnitude of energy transfer between the wave modes in the case of Langmuir wave decay. We demonstrate that these methods allow one to determine the relative importance of strongly and weakly turbulent processes. The statistical validity of the results was thoroughly tested using surrogated data set analysis.Key words. Space plasma physics (wave-wave interactions; experimental and mathematical techniques; nonlinear phenomena

  15. Statistical analysis of nonlinear wave interactions in simulated Langmuir turbulence data

    Directory of Open Access Journals (Sweden)

    J. Soucek

    Full Text Available We present a statistical analysis of strong turbulence of Langmuir and ion-sound waves resulting from beam-plasma interaction. The analysis is carried out on data sets produced by a numerical simulation of one-dimensional Zakharov’s equations. The nonlinear wave interactions are studied using two different approaches: high-order spectra and Volterra models. These methods were applied to identify two and three wave processes in the data, and the Volterra model was furthermore employed to evaluate the direction and magnitude of energy transfer between the wave modes in the case of Langmuir wave decay. We demonstrate that these methods allow one to determine the relative importance of strongly and weakly turbulent processes. The statistical validity of the results was thoroughly tested using surrogated data set analysis.

    Key words. Space plasma physics (wave-wave interactions; experimental and mathematical techniques; nonlinear phenomena

  16. Bioconjugation of peptides using advanced nanomaterials to examine their interactions in 3D printed flow-through device. (United States)

    Michalek, Petr; Richtera, Lukas; Krejcova, Ludmila; Nejdl, Lukas; Kensova, Renata; Zitka, Jan; Kopel, Pavel; Heger, Zbynek; Adam, Vojtech; Kizek, Rene


    Peptide-peptide interactions are crucial in the living cell as they lead to the formation of the numerous types of complexes. In this study, synthetic peptides containing 11 of cysteines (α-domain of metallothionein (MT)) and sialic acid binding region (130-loop of hemagglutinin (HA)) were employed. The aim of the experiment was studying the interactions between MT and HA-derived peptides. For this purpose, fragments were tagged with cysteines at C-terminal part to serve as ligand sites for PbS and CuS quantum dots (QDs), and therefore these conjugates can be traced and quantified during wide spectrum of methods. As a platform for interaction, γ-Fe2O3 paramagnetic particles modified with tetraethyl orthosilicate and (3-aminopropyl)triethoxysilane (hydrodynamic diameter 30-40 nm) were utilized and MT/HA interactions were examined using multi-instrumental approach including electrochemistry, electrophoretic methods, and MALDI-TOF/TOF mass spectrometry. It was found that peptides enter mutual creation of complexes, which are based on some of nonbonded interactions. The higher willingness to interact was observed in MT-derived peptides toward immobilized HA. Finally, we designed and manufactured flow-through electrochemical 3D printed device (reservoir volume 150 μL) and utilized it for automated analysis of the HA/MT metal labels. Under the optimal conditions, (deposition time and flow rate 80 s and 1.6 mL/min for CuS and 120 s and 1.6 mL/min PbS, respectively), the results of peptide-conjugated QDs were comparable with atomic absorption spectrometry. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. GSFLOW model simulations used to evaluate the impact of irrigated agriculture on surface water - groundwater interaction (United States)

    U.S. Geological Survey, Department of the Interior — Watershed-scale coupled surface water (SW) – groundwater (GW) flow modeling was used to examine changes in streamflow and SW – GW interaction resulting from...

  18. Microscale simulations of shock interaction with large assembly of particles for developing point-particle models (United States)

    Thakur, Siddharth; Neal, Chris; Mehta, Yash; Sridharan, Prasanth; Jackson, Thomas; Balachandar, S.


    Micrsoscale simulations are being conducted for developing point-particle and other related models that are needed for the mesoscale and macroscale simulations of explosive dispersal of particles. These particle models are required to compute (a) instantaneous aerodynamic force on the particle and (b) instantaneous net heat transfer between the particle and the surrounding. A strategy for a sequence of microscale simulations has been devised that allows systematic development of the hybrid surrogate models that are applicable at conditions representative of the explosive dispersal application. The ongoing microscale simulations seek to examine particle force dependence on: (a) Mach number, (b) Reynolds number, and (c) volume fraction (different particle arrangements such as cubic, face-centered cubic (FCC), body-centered cubic (BCC) and random). Future plans include investigation of sequences of fully-resolved microscale simulations consisting of an array of particles subjected to more realistic time-dependent flows that progressively better approximate the actual problem of explosive dispersal. Additionally, effects of particle shape, size, and number in simulation as well as the transient particle deformation dependence on various parameters including: (a) particle material, (b) medium material, (c) multiple particles, (d) incoming shock pressure and speed, (e) medium to particle impedance ratio, (f) particle shape and orientation to shock, etc. are being investigated.

  19. Modelling and simulation of unsteady dc electric arcs and their interactions with electrodes (United States)

    Chemartin, L.; Lalande, P.; Delalondre, C.; Cheron, B.; Lago, F.


    This paper is devoted to the study of unsteady electric arcs and the effects of electrodes on their dynamics. One of the objectives is to simulate and understand the three-dimensional behaviour of arcs in complex geometries, which create important fluctuations of the column and reattachments on the electrodes. The usual methods to solve the problem of arc-electrodes coupling are not suitable to simulate three-dimensional unsteady arcs. We propose a numerical development to simulate both steady-state and unsteady arcs without additional assumptions. The method is based on the incorporation of electrodes into the computational domain. It is validated with measurements from the literature, in the case of a point-plane steady-state argon arc. The model is used to study the lightning certification test device, which simulates in laboratory the effects of lightning arcs on fuselage panels. The results bring to light, in agreement with the observations in laboratory, the fundamental role of the electrodes on the three-dimensional behaviour of the arc column. The model is also used to simulate the development of the free jet of a plasma on an aluminium planar anode. The objective is to characterize the interaction region and the thermal constraint of the arc.

  20. Translating the simulation of procedural drilling techniques for interactive neurosurgical training. (United States)

    Stredney, Don; Rezai, Ali R; Prevedello, Daniel M; Elder, J Bradley; Kerwin, Thomas; Hittle, Bradley; Wiet, Gregory J


    Through previous efforts we have developed a fully virtual environment to provide procedural training of otologic surgical technique. The virtual environment is based on high-resolution volumetric data of the regional anatomy. These volumetric data help drive an interactive multisensory, ie, visual (stereo), aural (stereo), and tactile, simulation environment. Subsequently, we have extended our efforts to support the training of neurosurgical procedural technique as part of the Congress of Neurological Surgeons simulation initiative. To deliberately study the integration of simulation technologies into the neurosurgical curriculum and to determine their efficacy in teaching minimally invasive cranial and skull base approaches. We discuss issues of biofidelity and our methods to provide objective, quantitative and automated assessment for the residents. We conclude with a discussion of our experiences by reporting preliminary formative pilot studies and proposed approaches to take the simulation to the next level through additional validation studies. We have presented our efforts to translate an otologic simulation environment for use in the neurosurgical curriculum. We have demonstrated the initial proof of principles and define the steps to integrate and validate the system as an adjuvant to the neurosurgical curriculum.

  1. Flow-structure interaction simulation of voice production in a canine larynx (United States)

    Jiang, Weili; Zheng, Xudong; Xue, Qian; Oren, Liran; Khosla, Sid


    Experimental measurements conducted on a hemi-larynx canine vocal fold showed that negative pressures formed in the glottis near the superior surface of the vocal fold in the closing phase even without a supra-glottal vocal tract. It was hypothesized that such negative pressures were due to intraglottal vortices caused by flow separation in a divergent vocal tract during vocal fold closing phase. This work aims to test this hypothesis from the numerical aspect. Flow-structure interaction simulations are performed in realistic canine laryngeal shapes. In the simulations, a sharp interface immersed boundary method based incompressible flow solver is utilized to model the air flow; a finite element based solid mechanics solver is utilized to model the vocal fold vibration. The geometric structure of the vocal fold and vocal tract are based on MRI scans of a mongrel canine. The vocal fold tissue is modeled as transversely isotropic nonlinear materials with a vertical stiffness gradient. Numerical indentation is first performed and compared with the experiment data to obtain the material properties. Simulation setup about the inlet and outlet pressure follows the setup in the experiment. Simulation results including the fundamental frequency, air flow rate, the divergent angle will be compared with the experimental data, providing the validation of the simulation approach. The relationship between flow separation, intra-glottal vortices, divergent angle and flow rate will be comprehensively analyzed.

  2. SIPSON--simulation of interaction between pipe flow and surface overland flow in networks. (United States)

    Djordjević, S; Prodanović, D; Maksimović, C; Ivetić, M; Savić, D


    The new simulation model, named SIPSON, based on the Preissmann finite difference method and the conjugate gradient method, is presented in the paper. This model simulates conditions when the hydraulic capacity of a sewer system is exceeded, pipe flow is pressurized, the water flows out from the piped system to the streets, and the inlets cannot capture all the runoff. In the mathematical model, buried structures and pipelines, together with surface channels, make a horizontally and vertically looped network involving a complex interaction of flows. In this paper, special internal boundary conditions related to equivalent inlets are discussed. Procedures are described for the simulation of manhole cover loss, basement flooding, the representation of street geometry, and the distribution of runoff hydrographs between surface and underground networks. All these procedures are built into the simulation model. Relevant issues are illustrated on a set of examples, focusing on specific parameters and comparison with field measurements of flooding of the Motilal ki Chal catchment (Indore, India). Satisfactory agreement of observed and simulated hydrographs and maximum surface flooding levels is obtained. It is concluded that the presented approach is an improvement compared to the standard "virtual reservoir" approach commonly applied in most of the models.

  3. A review of fluid-structure interaction simulations of prosthetic heart valves. (United States)

    Borazjani, Iman


    Dysfunctional natural heart valves are replaced with prosthetic heart valves through surgery. However, prosthetic valves are far from ideal. Bioprosthetic heart valves (BHVs) suffer from early calcification and structural damages. Mechanical heart valves (MHVs) are durable but highly thrombogenic and require lifelong anticoagulant treatment. These complications are believed to be related to nonphysiologic flow patterns created by these valves. Fluid-structure interaction (FSI) simulations are essential in revealing the hemodynamics of these valves. By combining the three-dimensional (3D) flow field obtained from realistic FSI simulations with platelet activation models, nonphysiologic flow patterns can be identified. In this review paper, state-of-the-art methods for simulating FSI in heart valves are reviewed, and the flow physics uncovered by FSI simulations are discussed. Finally, the limitations of current methods are discussed, and future research directions are proposed as follows: (1) incorporation of realistic, image-based ventricle and atrium geometries; (2) comparing MHV and BHV under similar conditions to identify nonphysiologic flow patterns; (3) developing better models to estimate platelet activation potential to be incorporated into the simulations; and (4) identifying the optimum placement of the valves in both mitral and aortic positions.

  4. A Simulation Model for Drift Resistive Ballooning Turbulence Examining the Influence of Self-consistent Zonal Flows (United States)

    Cohen, Bruce; Umansky, Maxim; Joseph, Ilon


    Progress is reported on including self-consistent zonal flows in simulations of drift-resistive ballooning turbulence using the BOUT + + framework. Previous published work addressed the simulation of L-mode edge turbulence in realistic single-null tokamak geometry using the BOUT three-dimensional fluid code that solves Braginskii-based fluid equations. The effects of imposed sheared ExB poloidal rotation were included, with a static radial electric field fitted to experimental data. In new work our goal is to include the self-consistent effects on the radial electric field driven by the microturbulence, which contributes to the sheared ExB poloidal rotation (zonal flow generation). We describe a model for including self-consistent zonal flows and an algorithm for maintaining underlying plasma profiles to enable the simulation of steady-state turbulence. We examine the role of Braginskii viscous forces in providing necessary dissipation when including axisymmetric perturbations. We also report on some of the numerical difficulties associated with including the axisymmetric component of the fluctuating fields. This work was performed under the auspices of the U.S. Department of Energy under contract DE-AC52-07NA27344 at the Lawrence Livermore National Laboratory (LLNL-ABS-674950).

  5. Teaching Hyporheic and Groundwater Flow Concepts Using an Interactive Computer Simulation (United States)

    Stonedahl, S. H.; Stonedahl, F.


    We built an educational flow simulator with an interactive web-based interface that allows students to investigate the effects of arbitrary head functions on water flowing through various configurations of permeable/impermeable sediments. The domain consists of a 24 by 48 rectangular grid of sediments with no-flow bottom and side boundaries and a constant head surface water-groundwater (SWGW) interface boundary. The SWGW interface head function can be drawn freehand with the mouse or specified to be a step function, a sine curve, or a zig-zag function, where the amplitude and wavenumber parameters of the head functions are chosen by the user. The subsurface domain may be modified by drawing no-flow (impermeable) barriers in the sediment, changing any number of the 1152 grid cells into no flow cells. The program iteratively solves the Laplace equation to calculate head values at each grid cell within the sediment. Users can then start water particles along the SWGW interface and track their paths through the system to visualize the head-induced flow. Sediment cells can be color coded by head values or water speed. Exploring these systems with the simulator allows users to improve their understanding of the relationship between head and velocity as well as how the position of no-flow barriers impacts water flow in saturated sediments. These learning objectives are amenable to our target audience of undergraduate students, but younger (middle/high school) students may also be able to absorb key concepts by playing with the simulation. The structure of the simulation itself highlights the broader idea of simulation of natural processes through the discretization of continuous environments. The simulation was developed using the NetLogo platform and runs embedded in a webpage: The simulation source code is available and can readily be modified by other educators (or students) to create additional features and options.

  6. Examining real-time time-dependent density functional theory nonequilibrium simulations for the calculation of electronic stopping power (United States)

    Yost, Dillon C.; Yao, Yi; Kanai, Yosuke


    In ion irradiation processes, electronic stopping power describes the energy transfer rate from the irradiating ion to the target material's electrons. Due to the scarcity and significant uncertainties in experimental electronic stopping power data for materials beyond simple solids, there has been growing interest in the use of first-principles theory for calculating electronic stopping power. In recent years, advances in high-performance computing have opened the door to fully first-principles nonequilibrium simulations based on real-time time-dependent density functional theory (RT-TDDFT). While it has been demonstrated that the RT-TDDFT approach is capable of predicting electronic stopping power for a wide range of condensed matter systems, there has yet to be an exhaustive examination of the physical and numerical approximations involved and their effects on the calculated stopping power. We discuss the results of such a study for crystalline silicon with protons as irradiating ions. We examine the influences of key approximations in RT-TDDFT nonequilibrium simulations on the calculated electronic stopping power, including approximations related to basis sets, finite size effects, exchange-correlation approximation, pseudopotentials, and more. Finally, we propose a simple and efficient correction scheme to account for the contribution from core-electron excitations to the stopping power, as it was found to be significant for large proton velocities.

  7. Examining the Efficacy of Peer Network Interventions on the Social Interactions of High School Students with Autism Spectrum Disorder. (United States)

    Sreckovic, Melissa A; Hume, Kara; Able, Harriet


    Developing positive peer relationships is important. Unfortunately, due to challenges in social communication and increased complexity of peer groups during adolescence, many secondary students with autism spectrum disorder (ASD) engage in limited positive social interactions with peers. This study examined the effects of a peer network intervention implemented with three high school students with ASD. A multiple-baseline across participants design was used to evaluate the intervention on initiations and responses to and from students with ASD. The impact on frequency of victimization of students with ASD was also explored. Results indicate peer networks are effective at increasing social interactions of secondary students with ASD and provide preliminary support for the use of peer networks to reduce rates of bullying victimization.

  8. Framing medical tourism: an examination of appeal, risk, convalescence, accreditation, and interactivity in medical tourism web sites. (United States)

    Mason, Alicia; Wright, Kevin B


    This exploratory study analyzed the content of medical tourism Web sites in an attempt to examine how they convey information about benefits and risks of medical procedures, how they frame credibility, and the degree to which these Web sites include interactive features for consumers. Drawing upon framing theory, the researchers content analyzed a sample of 66 medical tourism Web sites throughout the world. The results indicated that medical tourism Web sites largely promote the benefits of medical procedures while downplaying the risks, and relatively little information regarding the credibility of these services appears. In addition, the presentation of benefits/risks, credibility, and Web site interactivity were found to differ by region and type of facility. The authors discuss the implications of these findings concerning the framing of medical tourism Web site content, future directions for research, and limitations.

  9. An interactive 2-D power-line modeling and simulation tool (United States)

    Hull, David; Adelman, Ross


    The U.S. Army Research Laboratory's Power-Line unmanned aerial vehicle (UAV) Modeling and Simulation (ARL-PLUMS) is a tool for estimating and analyzing quasi-static electric and magnetic fields due to power lines. This tool consists of an interactive 2-D graphical user interface (GUI) and a compute engine that can be used to calculate and visualize the E-Field and H-Field due to as many as seven conductors (two 3-phase circuits and a ground wire). ARL-PLUMS allows the user to set the geometry of the lines and the load conditions on those lines, and then calculate Ey, Ez, Hy, or Hz along a linear path or cutting plane, or in the form of a movie. The path can be along the ground or in the air to simulate the fields that might be observed, for example, by a robotic vehicle or a UAV. ARL-PLUMS makes several simplifying assumptions in order to allow simulations to be completed on a laptop PC interactively. In most cases, the results are excellent, providing a "90% solution" in just a few minutes of total modeling and simulation time. This paper describes the physics used by ARL-PLUMS, including the simplifying assumptions and the 2-D Method of Moments solver. Examples of electric and magnetic fields for different wire configurations, including typical 3-phase distribution and transmissions lines, are provided. Comparisons to similar results using a full 3-D model are also shown, and a discussion of errors that may be expected from the 2-D simulations is provided.

  10. Simulation of water-rock interaction in the yellowstone geothermal system using TOUGHREACT

    Energy Technology Data Exchange (ETDEWEB)

    Dobson, P.F.; Salah, S.; Spycher, N.; Sonnenthal, E.


    The Yellowstone geothermal system provides an ideal opportunity to test the ability of reactive transport models to accurately simulate water-rock interaction. Previous studies of the Yellowstone geothermal system have characterized water-rock interaction through analysis of rocks and fluids obtained from both surface and downhole samples. Fluid chemistry, rock mineralogy, permeability, porosity, and thermal data obtained from the Y-8 borehole in Upper Geyser Basin were used to constrain a series of reactive transport simulations of the Yellowstone geothermal system using TOUGHREACT. Three distinct stratigraphic units were encountered in the 153.4 m deep Y-8 drill core: volcaniclastic sandstone, perlitic rhyolitic lava, and nonwelded pumiceous tuff. The main alteration phases identified in the Y-8 core samples include clay minerals, zeolites, silica polymorphs, adularia, and calcite. Temperatures observed in the Y-8 borehole increase with depth from sub-boiling conditions at the surface to a maximum of 169.8 C at a depth of 104.1 m, with near-isothermal conditions persisting down to the well bottom. 1-D models of the Y-8 core hole were constructed to determine if TOUGHREACT could accurately predict the observed alteration mineral assemblage given the initial rock mineralogy and observed fluid chemistry and temperatures. Preliminary simulations involving the perlitic rhyolitic lava unit are consistent with the observed alteration of rhyolitic glass to form celadonite.

  11. Earthquake simulations with time-dependent nucleation and long-range interactions

    Directory of Open Access Journals (Sweden)

    J. H. Dieterich


    Full Text Available A model for rapid simulation of earthquake sequences is introduced which incorporates long-range elastic interactions among fault elements and time-dependent earthquake nucleation inferred from experimentally derived rate- and state-dependent fault constitutive properties. The model consists of a planar two-dimensional fault surface which is periodic in both the x- and y-directions. Elastic interactions among fault elements are represented by an array of elastic dislocations. Approximate solutions for earthquake nucleation and dynamics of earthquake slip are introduced which permit computations to proceed in steps that are determined by the transitions from one sliding state to the next. The transition-driven time stepping and avoidance of systems of simultaneous equations permit rapid simulation of large sequences of earthquake events on computers of modest capacity, while preserving characteristics of the nucleation and rupture propagation processes evident in more detailed models. Earthquakes simulated with this model reproduce many of the observed spatial and temporal characteristics of clustering phenomena including foreshock and aftershock sequences. Clustering arises because the time dependence of the nucleation process is highly sensitive to stress perturbations caused by nearby earthquakes. Rate of earthquake activity following a prior earthquake decays according to Omori's aftershock decay law and falls off with distance.

  12. Structures and orientation-dependent interaction forces of titania nanowires using molecular dynamics simulations (United States)

    Okeke, George; Antony, S. Joseph; Hammond, Robert B.; Ahmed, Kamran


    Engineering nanowires to develop new products and processes is highly topical due to their ability to provide highly enhanced physical, chemical, mechanical, thermal and electrical properties. In this work, using molecular dynamics simulations, we report fundamental information, about the structural and thermodynamic properties of individual anatase titania (TiO2) nanowires with cross-sectional diameters between 2 and 6 nm, and aspect ratio (length to diameter) of 6:1 at temperatures ranging from 300 to 3000 K. Estimates of the melting transition temperature of the nanowires are between 2000 and 2500 K. The melting transition temperature predicted from the radial distribution functions (RDFs) shows strong agreement with those predicted from the total energy profiles. Overall, the transition temperature is in reasonable agreement with melting points predicted from experiments and simulations reported in the literature for spherical nanoparticles of similar sizes. Hence, the melting transition temperature of TiO2 nanowires modelled here can be considered as shape independent. Furthermore, for the first time based on MD simulations, interaction forces between two nanowires are reported at ambient temperature (300 K) for different orientations: parallel, perpendicular and end-to-end. It is observed that end-to-end orientations manifested the strongest attraction forces, while the parallel and perpendicular orientations displayed weaker attractions. The results reported here could form a foundation in future multiscale modelling studies of the structured titania nanowire assemblies, depending on the inter-wire interaction forces.

  13. Numerical simulation and experimental research on interaction of micro-defects and laser ultrasonic signal (United States)

    Guo, Hualing; Zheng, Bin; Liu, Hui


    In the present research, the mechanism governing the interaction between laser-generated ultrasonic wave and the micro-defects on an aluminum plate has been studied by virtue of numerical simulation as well as practical experiments. Simulation results indicate that broadband ultrasonic waves are caused mainly by surface waves, and that the surface waves produced by micro-defects could be utilized for the detection of micro-defects because these waves reflect as much information of the defects as possible. In the research, a laser-generated ultrasonic wave testing system with a surface wave probe has been established for the detection of micro-defects, and the surface waves produced by the defects with different depths on an aluminum plate have been tested by using the system. The interaction between defect depth and the maximum amplitude of the surface wave and that between defect depth and the center frequency of the surface wave have also been analyzed in detail. Research results indicate that, when the defect depth is less than half of the wavelength of the surface wave, the maximum amplitude and the center frequency of the surface wave are in linear proportion to the defect depth. Sound consistency of experimental results with theoretical simulation indicates that the system as established in the present research could be adopted for the quantitative detection of micro-defects.

  14. Simulated interactions of pedestrian crossings and motorized vehicles in residential areas (United States)

    Wang, Yan; Peng, Zhongyi; Chen, Qun


    To evaluate whether motorized vehicles can travel through a residential area, this paper develops a cellular automata (CA) model to simulate the interactions between pedestrian crossings and motorized vehicles in a residential area. In this paper, pedestrians determine their crossing speed according to their judgments of the position and velocity of the upcoming vehicles. The pedestrians may walk slowly or quickly or even run, and the pedestrian crossing time influences the vehicle movement. In addition, the proposed model considers the safety margin time needed for pedestrians to cross, and pedestrian-vehicle conflict is considered using the vehicle collision avoidance rule. Through simulations of interactions of pedestrian crossings with motorized vehicles' movement on a typical road in a residential area, the average wait time for pedestrians to cross and the average vehicle velocity under different pedestrian crossing volumes, different vehicle flows and different maximum vehicle velocities are obtained. To avoid an excessive waiting time for pedestrians to cross, the vehicle flow should be less than 180 veh/h, which allows an average of less than 10 s of waiting time; if the vehicle flow rate is less than 36 veh/h, then the waiting time is approximately 1 s. Field observations are conducted to validate the simulation results.

  15. Examining Perceived Distance and Personal Authenticity as Mediators of the Effects of Ghost-Tweeting on Parasocial Interaction. (United States)

    Cohen, Elizabeth L; Tyler, William J


    A number of high-profile public figures hire ghost-tweeters to post to their social media accounts on their behalf, but no research has examined how this social media practice can affect followers' feelings of connection to the public figures. College students (n = 132) participated in an online experiment to examine the effect of ghost-tweeting practices on parasocial interaction (PSI) with social media figures. Tweet authorship (use of a ghost-tweeter or not) was manipulated. Ghost-tweeting resulted in reduced PSI. Perceptions of distance, but not personal authenticity mediated this effect. However, authenticity and distance did serially mediate the relationship between ghost-tweeting and PSI. These findings shed light on the process of PSI with celebrities and other media figures on social network sites.

  16. Interactive simulations of gas-turbine modular HTGR transients and heatup accidents

    Energy Technology Data Exchange (ETDEWEB)

    Ball, S.J.; Nypaver, D.J.


    An interactive workstation-based simulator has been developed for performing analyses of modular high-temperature gas-cooled reactor (MHTGR) core transients and accidents. It was originally developed at Oak Ridge National Laboratory for the US Nuclear Regulatory Commission to assess the licensability of the US Department of Energy (DOE) steam cycle design 350-MW(t) MHTGR. Subsequently, the code was modified under DOE sponsorship to simulate the 450-MW(t) Gas Turbine (GT) design and to aid in development and design studies. Features of the code (MORECA-GT) include detailed modeling of 3-D core thermal-hydraulics, interactive workstation capabilities that allow user/analyst or ``operator`` involvement in accident scenarios, and options for studying anticipated transients without scram (ATWS) events. In addition to the detailed models for the core, MORECA includes models for the vessel, Shutdown Cooling System (SCS), and Reactor Cavity Cooling System (RCCS), and core point kinetics to accommodate ATWS events. The balance of plant (BOP) is currently not modeled. The interactive workstation features include options for on-line parameter plots and 3-D graphic temperature profiling. The studies to date show that the proposed MHTGR designs are very robust and can generally withstand the consequences of even the extremely low probability postulated accidents with little or no damage to the reactor`s fuel or metallic components.

  17. [Simulating measles and rubella elimination levels according to social stratification and interaction]. (United States)

    Hincapié-Palacio, Doracelly; Ospina-Giraldo, Juan; Gómez-Arias, Rubén D; Uyi-Afuwape, Anthony; Chowell-Puente, Gerardo


    The study was aimed at comparing measles and rubella disease elimination levels in a homogeneous and heterogeneous population according to socioeconomic status with interactions amongst low- and high-income individuals and diversity in the average number of contacts amongst them. Effective reproductive rate simulations were deduced from a susceptibleinfected- recovered (SIR) mathematical model according to different immunisation rates using measles (1980 and 2005) and rubella (1998 and 2005) incidence data from Latin-America and the Caribbean. Low- and high-income individuals' social interaction and their average number of contacts were analysed by bipartite random network analysis. MAPLE 12 (Maplesoft Inc, Ontario Canada) software was used for making the simulations. The progress made in eliminating both diseases between both periods of time was reproduced in the socially-homogeneous population. Measles (2005) would be eliminated in high- and low-income groups; however, it would only be achieved in rubella (2005) if there were a high immunity rate amongst the low-income group. If the average number of contacts were varied, then rubella would not be eliminated, even with a 95 % immunity rate. Monitoring the elimination level in diseases like measles and rubella requires that socio-economic status be considered as well as the population's interaction pattern. Special attention should be paid to communities having diversity in their average number of contacts occurring in confined spaces such as displaced communities, prisons, educational establishments, or hospitals.

  18. Molecular dynamics simulations on interaction between bacterial proteins: Implication on pathogenic activities. (United States)

    Mondal, Manas; Chakrabarti, Jaydeb; Ghosh, Mahua


    We perform molecular dynamics simulation studies on interaction between bacterial proteins: an outer-membrane protein STY3179 and a yfdX protein STY3178 of Salmonella Typhi. STY3179 has been found to be involved in bacterial adhesion and invasion. STY3178 is recently biophysically characterized. It is a soluble protein having antibiotic binding and chaperon activity capabilities. These two proteins co-occur and are from neighboring gene in Salmonella Typhi-occurrence of homologs of both STY3178 and STY3179 are identified in many Gram-negative bacteria. We show using homology modeling, docking followed by molecular dynamics simulation that they can form a stable complex. STY3178 belongs to aqueous phase, while the beta barrel portion of STY3179 remains buried in DPPC bilayer with extra-cellular loops exposed to water. To understand the molecular basis of interaction between STY3178 and STY3179, we compute the conformational thermodynamics which indicate that these two proteins interact through polar and acidic residues belonging to their interfacial region. Conformational thermodynamics results further reveal instability of certain residues in extra-cellular loops of STY3179 upon complexation with STY3178 which is an indication for binding with host cell protein laminin. © 2017 Wiley Periodicals, Inc.

  19. Simulation of Fluid-Structure and Fluid-Mediated Structure-Structure Interactions in Stokes Regime Using Immersed Boundary Method

    Directory of Open Access Journals (Sweden)

    Masoud Baghalnezhad


    Full Text Available The Stokes flow induced by the motion of an elastic massless filament immersed in a two-dimensional fluid is studied. Initially, the filament is deviated from its equilibrium state and the fluid is at rest. The filament will induce fluid motion while returning to its equilibrium state. Two different test cases are examined. In both cases, the motion of a fixed-end massless filament induces the fluid motion inside a square domain. However, in the second test case, a deformable circular string is placed in the square domain and its interaction with the Stokes flow induced by the filament motion is studied. The interaction between the fluid and deformable body/bodies can become very complicated from the computational point of view. An immersed boundary method is used in the present study. In order to substantiate the accuracy of the numerical method employed, the simulated results associated with the Stokes flow induced by the motion of an extending star string are compared well with those obtained by the immersed interface method. The results show the ability and accuracy of the IBM method in solving the complicated fluid-structure and fluid-mediated structure-structure interaction problems happening in a wide variety of engineering and biological systems.

  20. A hybrid parallel architecture for electrostatic interactions in the simulation of dissipative particle dynamics (United States)

    Yang, Sheng-Chun; Lu, Zhong-Yuan; Qian, Hu-Jun; Wang, Yong-Lei; Han, Jie-Ping


    In this work, we upgraded the electrostatic interaction method of CU-ENUF (Yang, et al., 2016) which first applied CUNFFT (nonequispaced Fourier transforms based on CUDA) to the reciprocal-space electrostatic computation and made the computation of electrostatic interaction done thoroughly in GPU. The upgraded edition of CU-ENUF runs concurrently in a hybrid parallel way that enables the computation parallelizing on multiple computer nodes firstly, then further on the installed GPU in each computer. By this parallel strategy, the size of simulation system will be never restricted to the throughput of a single CPU or GPU. The most critical technical problem is how to parallelize a CUNFFT in the parallel strategy, which is conquered effectively by deep-seated research of basic principles and some algorithm skills. Furthermore, the upgraded method is capable of computing electrostatic interactions for both the atomistic molecular dynamics (MD) and the dissipative particle dynamics (DPD). Finally, the benchmarks conducted for validation and performance indicate that the upgraded method is able to not only present a good precision when setting suitable parameters, but also give an efficient way to compute electrostatic interactions for huge simulation systems. Program Files doi: Licensing provisions: GNU General Public License 3 (GPL) Programming language: C, C++, and CUDA C Supplementary material: The program is designed for effective electrostatic interactions of large-scale simulation systems, which runs on particular computers equipped with NVIDIA GPUs. It has been tested on (a) single computer node with Intel(R) Core(TM) i7-3770@ 3.40 GHz (CPU) and GTX 980 Ti (GPU), and (b) MPI parallel computer nodes with the same configurations. Nature of problem: For molecular dynamics simulation, the electrostatic interaction is the most time-consuming computation because of its long-range feature and slow convergence in simulation space

  1. Interaction of polar and nonpolar organic pollutants with soil organic matter: sorption experiments and molecular dynamics simulation. (United States)

    Ahmed, Ashour A; Thiele-Bruhn, Sören; Aziz, Saadullah G; Hilal, Rifaat H; Elroby, Shaaban A; Al-Youbi, Abdulrahman O; Leinweber, Peter; Kühn, Oliver


    The fate of organic pollutants in the environment is influenced by several factors including the type and strength of their interactions with soil components especially SOM. However, a molecular level answer to the question "How organic pollutants interact with SOM?" is still lacking. In order to explore mechanisms of this interaction, we have developed a new SOM model and carried out molecular dynamics (MD) simulations in parallel with sorption experiments. The new SOM model comprises free SOM functional groups (carboxylic acid and naphthalene) as well as SOM cavities (with two different sizes), simulating the soil voids, containing the same SOM functional groups. To examine the effect of the hydrophobicity on the interaction, the organic pollutants hexachlorobenzene (HCB, non-polar) and sulfanilamide (SAA, polar) were considered. The experimental and theoretical investigations explored four major points regarding sorption of SAA and HCB on soil, yielding the following results. 1--The interaction depends on the SOM chemical composition more than the SOM content. 2--The interaction causes a site-specific adsorption on the soil surfaces. 3--Sorption hysteresis occurs, which can be explained by inclusion of these pollutants inside soil voids. 4--The hydrophobic HCB is adsorbed on soil stronger than the hydrophilic SAA. Moreover, the theoretical results showed that HCB forms stable complexes with all SOM models in the aqueous solution, while most of SAA-SOM complexes are accompanied by dissociation into SAA and the free SOM models. The SOM-cavity modeling had a significant effect on binding of organic pollutants to SOM. Both HCB and SAA bind to the SOM models in the order of models with a small cavity>a large cavity>no cavity. Although HCB binds to all SOM models stronger than SAA, the latter is more affected by the presence of the cavity. Finally, HCB and SAA bind to the hydrophobic functional group (naphthalene) stronger than to the hydrophilic one (carboxylic acid

  2. Distinguishing cold dark matter dwarfs from self-interacting dark matter dwarfs in baryonic simulations (United States)

    Strickland, Emily; Fitts, Alex; Boylan-Kolchin, Michael


    Our collaboration has simulated several high-resolution (mbaryon = 500Mo, mdm = 2500Mo) cosmological zoom-in simulations of isolated dwarf galaxies. We simulate each galaxy in standard cold dark matter (ΛCDM) as well as a self-interacting dark matter (SIDM) (with a cross section of σ/m ~ 1 cm2/g), both with and without baryons, to identify distinguishing characteristics between the two. The simulations are run using GIZMO, a meshless-finite-mass (MFM) hydrodynamical code, and are part of the Feedback in Realistic Environments (FIRE) project. By analyzing both the global properties and inner structure of the dwarfs in varying dark matter prescriptions, we provide a side-by-side comparison of isolated, dark matter dominated galaxies at the mass scale where differences in the two models of dark matter are thought to be the most obvious. We find that the edge of classical dwarfs and ultra-faint dwarfs (UFDs) (at ~105 Mo) provides the clearest window for distinguishing between the two theories. Here our SIDM galaxies continue to display a cored inner profile unlike their CDM counterparts. The SIDM versions of each galaxy also have measurably lower stellar velocity dispersions than their CDM counterparts.

  3. Simulating winter interactions among ungulates, vegetation, and fire in Northern Yellowstone Park

    Energy Technology Data Exchange (ETDEWEB)

    Turner, M.G.; Wu, T.; Brenkert, A. (Oak Ridge National Lab., TN (United States)); Wallace, L.L. (Univ. of Oklahoma, Norman, OK (United States)); Romme, W.H. (Fort Lewis College, Durango, CO (United States))


    The interaction of large-scale fire, vegetation, and ungulates is an important management issue in Yellowstone National Park. A spatially explicit individual-based simulation model was developed to explore the effects of fire scale and pattern on the winter foraging dynamics and survival of free-ranging elk (Cervus elaphus) and bison (Bison bison) in northern Yellowstone National Park. The Northern Yellowstone Park (NOYELP) model simulates the search, movement, and foraging activities of individuals or small groups of elk and bison. The 77 020-ha landscape is represented as a gridded irregular polygon with a spatial resolution of 1 ha. Forage intake is a function of an animal's initial body mass, the absolute amount of forage available on a site, and the depth and density of snow. When the energy expenditures of an animal exceed the energy gained during a day, the animal's endogenous reserves are reduced to offset the deficits. Simulations are conducted with a 1-d time step for a duration of 180 d, [approximately]1 November through the end of April. Simulated elk survival for three winters (1987-1988; 1988-1989; 1990-1991) agreed with observed data.

  4. Fluid-structure interaction simulations of deformable structures with non-linear thin shell elements (United States)

    Asgharzadeh, Hafez; Hedayat, Mohammadali; Borazjani, Iman; Scientific Computing; Biofluids Laboratory Team


    Large deformation of structures in a fluid is simulated using a strongly coupled partitioned fluid-structure interaction (FSI) approach which is stabilized with under-relaxation and the Aitken acceleration technique. The fluid is simulated using a recently developed implicit Newton-Krylov method with a novel analytical Jacobian. Structures are simulated using a triangular thin-shell finite element formulation, which considers only translational degrees of freedom. The thin-shell method is developed on the top of a previously implemented membrane finite element formulation. A sharp interface immersed boundary method is used to handle structures in the fluid domain. The developed FSI framework is validated against two three-dimensional experiments: (1) a flexible aquatic vegetation in the fluid and (2) a heaving flexible panel in fluid. Furthermore, the developed FSI framework is used to simulate tissue heart valves, which involve large deformations and non-linear material properties. This work was supported by American Heart Association (AHA) Grant 13SDG17220022 and the Center of Computational Research (CCR) of University at Buffalo.

  5. Mechanism of mRNA-STAR domain interaction: Molecular dynamics simulations of Mammalian Quaking STAR protein. (United States)

    Sharma, Monika; Anirudh, C R


    STAR proteins are evolutionary conserved mRNA-binding proteins that post-transcriptionally regulate gene expression at all stages of RNA metabolism. These proteins possess conserved STAR domain that recognizes identical RNA regulatory elements as YUAAY. Recently reported crystal structures show that STAR domain is composed of N-terminal QUA1, K-homology domain (KH) and C-terminal QUA2, and mRNA binding is mediated by KH-QUA2 domain. Here, we present simulation studies done to investigate binding of mRNA to STAR protein, mammalian Quaking protein (QKI). We carried out conventional MD simulations of STAR domain in presence and absence of mRNA, and studied the impact of mRNA on the stability, dynamics and underlying allosteric mechanism of STAR domain. Our unbiased simulations results show that presence of mRNA stabilizes the overall STAR domain by reducing the structural deviations, correlating the 'within-domain' motions, and maintaining the native contacts information. Absence of mRNA not only influenced the essential modes of motion of STAR domain, but also affected the connectivity of networks within STAR domain. We further explored the dissociation of mRNA from STAR domain using umbrella sampling simulations, and the results suggest that mRNA binding to STAR domain occurs in multi-step: first conformational selection of mRNA backbone conformations, followed by induced fit mechanism as nucleobases interact with STAR domain.

  6. Animating multiple interacting miscible and immiscible fluids based on particle simulation

    Directory of Open Access Journals (Sweden)

    Onderik Juraj


    Full Text Available We present a particle-based approach for animating multiple interacting liquids that can handle number of immiscible fluids as well as number of miscible fluids in our simulation framework. We solve the usual problem of robust interface tracking, between immiscible fluids, by reconstructing the zero level set of our novel composite implicit function, see Fig. 1 left and center. It’s recurrent formulation handles directly interfaces between any number of liquids including the free surfaces. We model the miscible fluids by tracking concentrations of dissolved materials in the vicinity of each particle. Flick’s law is applied for the Laplacian-based diffusion of concentrations, see Fig. 1 right. Particle sedimentation is achieved by directional advection along the settling velocity. The diffusion-advection equation is discretized by particles using the Lagrangian formulation. The proposed improvements can be easily implemented into the common Smoothed Particle Hydrodynamics (SPH simulations framework

  7. partiview: Immersive 4D Interactive Visualization of Large-Scale Simulations (United States)

    Levy, Stuart


    In dense clusters a bewildering variety of interactions between stars can be observed, ranging from simple encounters to collisions and other mass-transfer encounters. With faster and special-purpose computers like GRAPE, the amount of data per simulation is now exceeding 1TB. Visualization of such data has now become a complex 4D data-mining problem, combining space and time, and finding interesting events in these large datasets. We have recently starting using the virtual reality simulator, installed in the Hayden Planetarium in the American Museum for Natural History, to tackle some of these problem. partiview is a program that enables you to visualize and animate particle data. partiview runs on relatively simple desktops and laptops, but is mostly compatible with its big brother VirDir.

  8. Ion dynamics in electron beam–plasma interaction: particle-in-cell simulations

    Directory of Open Access Journals (Sweden)

    K. Baumgärtel


    Full Text Available Electron beam–plasma interaction including ions is studied by particle-in-cell (PIC simulations using a one-dimensional, electrostatic code. Evidence for Langmuir wave decay is given for sufficiently energetic beams, as in previous Vlasov–Maxwell simulations. The mechanism for the generation of localized finite-amplitude ion density fluctuations is analyzed. Amplitude modulation due to interference between the beam-generated Langmuir waves causes random wave localization including strong transient spikes in field intensity which create bursty ion density structures via ponderomotive forces. More dense beams may quench the decay instability and generate low-frequency variations dominated by the wave number of the fastest growing Langmuir mode.

  9. Simulation and Prediction of Wakes and Wake Interaction in Wind Farms

    DEFF Research Database (Denmark)

    Andersen, Søren Juhl

    coupled with the flow solver. The numerical simulations include the study of the far wake behind a single turbine, three idealised cases of infinitely long rows of turbines and finally three infinite wind farm scenarios with different spacings. The flow characteristics between the turbines, turbine...... the basis for two proposed dynamic wake models of the turbulent wake deep inside large wind farms. The first model is based on a direct reconstruction using POD, while the other model (REDOMO) is based on an additional reduction by only including the most dominant frequencies. The flow fields derived from......The highly turbulent wake and the wake interaction of merging wakes between multiple wind turbines are modelled using Large Eddy Simulation (LES) in a general Navier-Stokes solver. The Actuator Line (AL) technique is employed to model the wind turbines, and the aeroelastic computations are fully...

  10. Simulation of charge exchange neutrals interactions with gaps in first wall cladding

    Energy Technology Data Exchange (ETDEWEB)

    Kurnaev, V.A. [Moscow Engineering and Physics Institute, Kashirskoe sh. 31, 115409 Moscow (Russian Federation)]. E-mail:; Matveev, D.I. [Moscow Engineering and Physics Institute, Kashirskoe sh. 31, 115409 Moscow (Russian Federation); Trifonov, N.N. [Moscow Engineering and Physics Institute, Kashirskoe sh. 31, 115409 Moscow (Russian Federation)


    Angular distributions of particles impinging PFC in fusion devices with magnetic confinement are briefly discussed. It is shown that simulation of charge exchange neutrals interaction with the first wall should be made for inclined incidence of particles. Particle reflection coefficients and sputtering yields for gaps in Be, C and W first wall cladding are found with Monte Carlo computer simulations for hydrogen isotopes in the energy range {approx}5-5 x 10{sup 3} eV as well as for the flux integrated over the ITER charge exchange neutrals energy spectrum. Trapping of deuterons by the gap in the W wall increases two times (up to {approx}0.6) as compared with the flat surface, while trapping in the Be gap is close to unity. The influence of isotope mass on trapping and sputtering is shown to follow data for the flat surface. Roughness of gap sidewalls taken into account slightly contributes to calculated data.

  11. A rectangular tetrahedral adaptive mesh based corotated finite element model for interactive soft tissue simulation. (United States)

    Tagawa, Kazuyoshi; Yamada, Takahiro; Tanaka, Hiromi T


    In this paper, we propose a rectangular tetrahedral adaptive mesh based corotated finite element model for interactive soft tissue simulation. Our approach consists of several computation reduction techniques. They are as follows: 1) an efficient calculation approach for computing internal forces of nodes of elastic objects to take advantage of the rectangularity of the tetrahedral adaptive mesh; 2) fast shape matching approach by using a new scaling of polar decomposition; 3) an approach for the reduction of the number of times of shape matching by using the hierarchical structure. We implemented the approach into our surgery simulator and compared the accuracy of the deformation and the computation time among 1) proposed approach, 2) L-FE), and 3) NL-FEM. Finally, we show the effectiveness of our proposed approach.

  12. Effect of sacral magnetic stimulation on the anorectal manometric activity: a new modality for examining sacro-rectoanal interaction. (United States)

    Kubota, Masayuki; Okuyama, Naoki; Hirayama, Yutaka; Kobayashi, Kumiko; Satoh, Kanako


    We examined the interaction between the sacral neural system and the anorectal activity using a technique comprising repetitive magnetic stimulation. Thirteen control children without any bowel dysmotility (age range; 3 month old to 15 year old), 20 patients with chronic constipation (1 month old to 14 year old), and nine pre-operative patients with Hirschsprung's disease (1 month old to 6 year old) were examined. Magnetic stimulation was applied at the S3 level using the MagPro (Medtronic) device while simultaneously performing manometric recordings of the anorectal activity. In the 13 controls and the 20 patients with chronic constipation, the rectoanal reflex was demonstrated by balloon rectal dilatation. The sphincter response to magnetic stimulation was biphasic in the controls, consisting of an initial rise followed by a decrease in the sphincter pressure, while it varied among the patients with chronic constipation including a biphasic response in 16 patients, no response in three patients, and only a transient rise in pressure in one patient. In nine pre-operative patients with Hirschsprung's disease, no rectoanal reflex was observed, however, the sphincter pressure increased due to magnetic stimulation in six patients, while three patients exhibited no recordable responses. These results suggest that the repetitive magnetic stimulation technique is a valuable modality for investigating the neural interaction between the sacral nervous system and the anorectum.

  13. Examination of the Impact of Using an Interactive Electronic Textbook on the Affective Learning of Prospective Mathematics Teachers

    Directory of Open Access Journals (Sweden)

    Sakine Öngöz


    Full Text Available This semi-experimental study aims to examine the impact of a learning environment that uses interactive electronic textbook on the affective learning of prospective mathematics teachers. The study group consisted of 64 prospective teachers attending the Mathematics Teaching program at Karadeniz Technical University, Turkey. For 14 weeks, experimental group received the Development and Learning course in a blended learning environment, in which an interactive e-textbook was used inside and outside the classroom. In this period, only face to face education was conducted with the control group in the classroom environment. A course attitude scale and a blended learning environment satisfaction scale were employed for the purpose of data collection. In addition, observations were conducted with both of the groups during the application. The analysis of the findings indicated that there was a significant increase between pre- and post-course attitude scores of experimental group students, the students were satisfied with the learning environment formed, and the electronic text book increased interest in the course.Key Words: Interactive electronic textbook, prospective mathematics teachers, blended learning model, affective learning

  14. Real-time 3-D hybrid simulation of Titan's plasma interaction during a solar wind excursion

    Directory of Open Access Journals (Sweden)

    S. Simon


    Full Text Available The plasma environment of Saturn's largest satellite Titan is known to be highly variable. Since Titan's orbit is located within the outer magnetosphere of Saturn, the moon can leave the region dominated by the magnetic field of its parent body in times of high solar wind dynamic pressure and interact with the thermalized magnetosheath plasma or even with the unshocked solar wind. By applying a three-dimensional hybrid simulation code (kinetic description of ions, fluid electrons, we study in real-time the transition that Titan's plasma environment undergoes when the moon leaves Saturn's magnetosphere and enters the supermagnetosonic solar wind. In the simulation, the transition between both plasma regimes is mimicked by a reversal of the magnetic field direction as well as a change in the composition and temperature of the impinging plasma flow. When the satellite enters the solar wind, the magnetic draping pattern in its vicinity is reconfigured due to reconnection, with the characteristic time scale of this process being determined by the convection of the field lines in the undisturbed plasma flow at the flanks of the interaction region. The build-up of a bow shock ahead of Titan takes place on a typical time scale of a few minutes as well. We also analyze the erosion of the newly formed shock front upstream of Titan that commences when the moon re-enters the submagnetosonic plasma regime of Saturn's magnetosphere. Although the model presented here is far from governing the full complexity of Titan's plasma interaction during a solar wind excursion, the simulation provides important insights into general plasma-physical processes associated with such a disruptive change of the upstream flow conditions.

  15. Multi-scale interactions of geological processes during mineralization: cascade dynamics model and multifractal simulation

    Directory of Open Access Journals (Sweden)

    L. Yao


    Full Text Available Relations between mineralization and certain geological processes are established mostly by geologist's knowledge of field observations. However, these relations are descriptive and a quantitative model of how certain geological processes strengthen or hinder mineralization is not clear, that is to say, the mechanism of the interactions between mineralization and the geological framework has not been thoroughly studied. The dynamics behind these interactions are key in the understanding of fractal or multifractal formations caused by mineralization, among which singularities arise due to anomalous concentration of metals in narrow space. From a statistical point of view, we think that cascade dynamics play an important role in mineralization and studying them can reveal the nature of the various interactions throughout the process. We have constructed a multiplicative cascade model to simulate these dynamics. The probabilities of mineral deposit occurrences are used to represent direct results of mineralization. Multifractal simulation of probabilities of mineral potential based on our model is exemplified by a case study dealing with hydrothermal gold deposits in southern Nova Scotia, Canada. The extent of the impacts of certain geological processes on gold mineralization is related to the scale of the cascade process, especially to the maximum cascade division number nmax. Our research helps to understand how the singularity occurs during mineralization, which remains unanswered up to now, and the simulation may provide a more accurate distribution of mineral deposit occurrences that can be used to improve the results of the weights of evidence model in mapping mineral potential.

  16. High Fidelity Aeroelasticity Simulations of Aircraft and Turbomachinery with Fully-Coupled Fluid-Structure Interaction (United States)

    Gan, Jiaye

    The purpose of this research is to develop high fidelity numerical methods to investigate the complex aeroelasticity fluid-structural problems of aircraft and aircraft engine turbomachinery. Unsteady 3D compressible Navier-Stokes equations in generalized coordinates are solved to simulate the complex fluid dynamic problems in aeroelasticity. An efficient and low diffusion E-CUSP (LDE) scheme designed to minimize numerical dissipation is used as a Riemann solver to capture shock waves in transonic and supersonic flows. An improved hybrid turbulence modeling, delayed detached eddy simulation (DDES), is implemented to simulate shock induced separation and rotating stall flows. High order accuracy (3rd and 5th order) weighted essentially non-oscillatory (WENO) schemes for inviscid flux and a conservative 2nd and 4th order viscous flux differencing are employed. To resolve the nonlinear interaction between flow and vibrating blade structures, a fully coupled fluid-structure interaction (FSI) procedure that solves the structural modal equations and time accurate Navier-Stokes equations simultaneously is adopted. A rotor/stator sliding interpolation technique is developed to accurately capture the blade rows interaction at the interface with general grid distribution. Phase lag boundary conditions (BC) based on the time shift (direct store) method and the Fourier series phase lag BC are applied to consider the effect of phase difference for a sector of annulus simulation. Extensive validations are conducted to demonstrate high accuracy and robustness of the high fidelity FSI methodology. The accuracy and robustness of RANS, URANS and DDES turbulence models with high order schemes for predicting the lift and drag of the DLR-F6 configuration are verified. The DDES predicts the drag very well whereas the URANS model significantly over predicts the drag. DDES of a finned projectile base flows is conducted to further validate the high fidelity methods with vortical flow. The

  17. Rescaled Local Interaction Simulation Approach for Shear Wave Propagation Modelling in Magnetic Resonance Elastography (United States)

    Packo, P.; Staszewski, W. J.; Uhl, T.


    Properties of soft biological tissues are increasingly used in medical diagnosis to detect various abnormalities, for example, in liver fibrosis or breast tumors. It is well known that mechanical stiffness of human organs can be obtained from organ responses to shear stress waves through Magnetic Resonance Elastography. The Local Interaction Simulation Approach is proposed for effective modelling of shear wave propagation in soft tissues. The results are validated using experimental data from Magnetic Resonance Elastography. These results show the potential of the method for shear wave propagation modelling in soft tissues. The major advantage of the proposed approach is a significant reduction of computational effort. PMID:26884808

  18. On the concept of the interactive information and simulation system for gas dynamics and multiphysics problems (United States)

    Bessonov, O.; Silvestrov, P.


    This paper describes the general idea and the first implementation of the Interactive information and simulation system - an integrated environment that combines computational modules for modeling the aerodynamics and aerothermodynamics of re-entry space vehicles with the large collection of different information materials on this topic. The internal organization and the composition of the system are described and illustrated. Examples of the computational and information output are presented. The system has the unified implementation for Windows and Linux operation systems and can be deployed on any modern high-performance personal computer.

  19. A Participatory Design Approach to Develop an Interactive Sound Environment Simulator. (United States)

    Hanssen, Geir K; Dahl, Yngve


    Our purpose is to provide insight into the added value of applying a participatory design approach in the design of an interactive sound environment simulator to facilitate communication and understanding between patients and audiologists in consultation situations. We have applied a qualitative approach, presenting results and discussion in the form of a story, following 3 consecutive steps: problem investigation, design, and evaluation. We provide an overview of lessons learned, emphasizing how patients and audiologists took roles and responsibilities in the design process and the effects of this involvement. Our results suggest that participatory design is a viable and practical approach to address multifaceted problems directly affecting patients and practitioners.

  20. Rescaled Local Interaction Simulation Approach for Shear Wave Propagation Modelling in Magnetic Resonance Elastography

    Directory of Open Access Journals (Sweden)

    Z. Hashemiyan


    Full Text Available Properties of soft biological tissues are increasingly used in medical diagnosis to detect various abnormalities, for example, in liver fibrosis or breast tumors. It is well known that mechanical stiffness of human organs can be obtained from organ responses to shear stress waves through Magnetic Resonance Elastography. The Local Interaction Simulation Approach is proposed for effective modelling of shear wave propagation in soft tissues. The results are validated using experimental data from Magnetic Resonance Elastography. These results show the potential of the method for shear wave propagation modelling in soft tissues. The major advantage of the proposed approach is a significant reduction of computational effort.

  1. Flow structure interaction around an axial-flow hydrokinetic turbine: Experiments and CFD simulations (United States)

    Kang, S.; Chamorro, L.; Hill, C.; Arndt, R.; Sotiropoulos, F.


    We carry out large-eddy simulation of turbulent flow past a complete hydrokinetic turbine mounted on the bed of a straight rectangular open channel. The complex turbine geometry, including the rotor and all stationary components, is handled by employing the curvilinear immersed boundary (CURVIB) method [1], and velocity boundary conditions near all solid surfaces are reconstructed using a wall model based on solving the simplified boundary layer equations [2]. In this study we attempt to directly resolve flow-blade interactions without introducing turbine parameterization methods. The computed wake profiles of velocities and turbulent stresses agree well with the experimentally measured values.

  2. A digital computer program for the dynamic interaction simulation of controls and structure (DISCOS), volume 1 (United States)

    Bodley, C. S.; Devers, A. D.; Park, A. C.; Frisch, H. P.


    A theoretical development and associated digital computer program system for the dynamic simulation and stability analysis of passive and actively controlled spacecraft are presented. The dynamic system (spacecraft) is modeled as an assembly of rigid and/or flexible bodies not necessarily in a topological tree configuration. The computer program system is used to investigate total system dynamic characteristics, including interaction effects between rigid and/or flexible bodies, control systems, and a wide range of environmental loadings. In addition, the program system is used for designing attitude control systems and for evaluating total dynamic system performance, including time domain response and frequency domain stability analyses.

  3. Interaction of lysozyme with a tear film lipid layer model: A molecular dynamics simulation study. (United States)

    Wizert, Alicja; Iskander, D Robert; Cwiklik, Lukasz


    The tear film is a thin multilayered structure covering the cornea. Its outermost layer is a lipid film underneath of which resides on an aqueous layer. This tear film lipid layer (TFLL) is itself a complex structure, formed by both polar and nonpolar lipids. It was recently suggested that due to tear film dynamics, TFLL contains inhomogeneities in the form of polar lipid aggregates. The aqueous phase of tear film contains lachrymal-origin proteins, whereby lysozyme is the most abundant. These proteins can alter TFLL properties, mainly by reducing its surface tension. However, a detailed nature of protein-lipid interactions in tear film is not known. We investigate the interactions of lysozyme with TFLL in molecular details by employing coarse-grained molecular dynamics simulations. We demonstrate that lysozyme, due to lateral restructuring of TFLL, is able to penetrate the tear lipid film embedded in inverse micellar aggregates. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Emergence of Alpha and Gamma Like Rhythms in a Large Scale Simulation of Interacting Neurons (United States)

    Gaebler, Philipp; Miller, Bruce


    In the normal brain, at first glance the electrical activity appears very random. However, certain frequencies emerge during specific stages of sleep or between quiet wake states. This raises the question of whether current mathematical and computational models of interacting neurons can display similar behavior. A recent model developed by Eugene Izhikevich appears to succeed. However, early dynamical simulations used to detect these patterns were possibly compromised by an over-simplified initial condition and evolution algorithm. Utilizing the same model, but a more robust algorithm, here we present our initial results, showing that these patterns persist under a wide range of initial conditions. We employ spectral analysis of the firing patterns of a system of interacting excitatory and inhibitory neurons to demonstrate a bimodal spectrum centered on two frequencies in the range characteristic of alpha and gamma rhythms in the human brain.

  5. Influence of Concrete Properties on Molten Core-Concrete Interaction: A Simulation Study

    Directory of Open Access Journals (Sweden)

    Jin-yang Jiang


    Full Text Available In a severe nuclear power plant accident, the molten core can be released into the reactor pit and interact with sacrificial concrete. In this paper, a simulation study is presented that aims to address the influence of sacrificial concrete properties on molten core-concrete interaction (MCCI. In particular, based on the MELCOR Code, the ferrosiliceous concrete used in European Pressurized Water Reactor (EPR is taken into account with respect to the different ablation enthalpy and Fe2O3 and H2O contents. Results indicate that the concrete ablation rate as well as the hydrogen generation rate depends much on the concrete ablation enthalpy and Fe2O3 and H2O contents. In practice, the ablation enthalpy of sacrificial concrete is the higher the better, while the Fe2O3 and H2O content of sacrificial concrete is the lower the better.

  6. Equilibrium magnetization and microstructure of the system of superparamagnetic interacting particles: numerical simulation

    CERN Document Server

    Pshenichnikov, A F


    The Monte Carlo method is used to study the equilibrium magnetization of a 3D system of superparamagnetic particles taking into account the steric and dipole-dipole interparticle interactions. Two types of systems are considered: magnetic fluids and solidified ferrocolloids containing randomly spatially distributed particles with negligible energy of magnetic anisotropy. The results of numerical simulations confirm the universality of Langevin susceptibility as a main dimensionless parameter determining the influence of interparticle interactions on the magnetization of the system for moderate values of the aggregation parameter. The obtained results are in good agreement with theoretical and experimental data. At large values of the aggregation parameter, the clustering of particles in magnetic fluids is observed resulting in a reduction of their magnetization as compared to solidified systems. It is shown that the magnetization of solidified systems can be well described by the modified effective field appr...

  7. Simulating the interaction of road users: A glance to complexity of Venezuelan traffic

    CERN Document Server

    Correa, Juan C; Bazzan, Ana L C; Jaffe, Klaus


    Automotive traffic is a classical example of a complex system, being the simplest case the homogeneous traffic where all vehicles are of the same kind, and using different means of transportation increases complexity due to different driving rules and interactions between each vehicle type. In particular, when motorcyclists drive in between the lanes of stopped or slow-moving vehicles. This later driving mode is a Venezuelan pervasive practice of mobilization that clearly jeopardizes road safety. We developed a minimalist agent-based model to analyze the interaction of road users with and without motorcyclists on the way. The presence of motorcyclists dwindles significantly the frequency of lane changes of motorists while increasing their frequency of acceleration-deceleration maneuvers, without significantly affecting their average speed. That is, motorcyclist "corralled" motorists in their lanes limiting their ability to maneuver and increasing their acceleration noise. Comparison of the simulations with re...

  8. Interaction of flavokawain B with lysozyme: A photophysical and molecular simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Feroz, Shevin R.; Teoh, Yue Jun [Biomolecular Research Group, Biochemistry Programme, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Mohamad, Saharuddin B. [Bioinformatics Programme, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Centre of Research for Computational Sciences and Informatics for Biology, Bioindustry, Environment, Agriculture and Healthcare, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Hong, Sok Lai; Malek, Sri N.A. [Biomolecular Research Group, Biochemistry Programme, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Tayyab, Saad, E-mail: [Biomolecular Research Group, Biochemistry Programme, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Centre of Research for Computational Sciences and Informatics for Biology, Bioindustry, Environment, Agriculture and Healthcare, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)


    Interaction of flavokawain B (FB), a therapeutic flavonoid with lysozyme (LYZ), was studied using various spectroscopic and molecular simulation techniques. The association constant, K{sub a} of the binding reaction was determined to be 2.79±0.16×10{sup 4} M{sup −1} at 25 °C based on fluorescence quenching titration results. Thermodynamic analysis of the binding data obtained at different temperatures along with molecular docking results suggested the involvement of hydrophobic and van der Waals forces, as well as hydrogen bonding in FB–LYZ interaction. The binding reaction between FB and LYZ was found to affect the microenvironment around protein fluorophores (Tyr and Trp) as revealed by intrinsic and three-dimensional fluorescence results. A comparison of the LYZ thermograms, obtained by far-UV CD spectroscopy in the absence and the presence of FB, suggested improved protein thermal stability upon complexation with FB. Presence of metal ions was found to affect FB–LYZ interaction. Molecular docking predicted the formation of two hydrogen bonds between the oxygen atoms of FB and amino acid residues of LYZ (Asn-59 and Trp-63), located in the vicinity of the active site, in addition to various non-polar contacts. Molecular dynamics studies showed that the complex reached equilibrium during simulation, indicating the stability of the FB–LYZ complex. - Highlights: • Role of hydrogen bonds, hydrophobic and van der Waals forces in FB–LYZ interaction. • Moderate affinity between FB and LYZ. • Alteration in the microenvironment around protein fluorophores upon FB binding. • Presence of the FB binding locus in the vicinity of LYZ active site.

  9. Integrating international relations and environmental science course concepts through an interactive world politics simulation (United States)

    Straub, K. H.; Kesgin, B.


    During the fall 2012 semester, students in two introductory courses at Susquehanna University - EENV:101 Environmental Science and POLI:131 World Affairs - will participate together in an online international relations simulation called Statecraft ( In this strategy game, students are divided into teams representing independent countries, and choose their government type (democracy, constitutional monarchy, communist totalitarian, or military dictatorship) and two country attributes (industrial, green, militaristic, pacifist, or scientific), which determine a set of rules by which that country must abide. Countries interact over issues such as resource distribution, war, pollution, immigration, and global climate change, and must also keep domestic political unrest to a minimum in order to succeed in the game. This simulation has typically been run in political science courses, as the goal is to allow students to experience the balancing act necessary to maintain control of global and domestic issues in a dynamic, diverse world. This semester, environmental science students will be integrated into the simulation, both as environmental advisers to each country and as independent actors representing groups such as Greenpeace, ExxonMobil, and UNEP. The goal in integrating the two courses in the simulation is for the students in each course to gain both 1) content knowledge of certain fundamental material in the other course, and 2) a more thorough, applied understanding of the integrated nature of the two subjects. Students will gain an appreciation for the multiple tradeoffs that decision-makers must face in the real world (economy, resources, pollution, health, defense, etc.). Environmental science students will link these concepts to the traditional course material through a "systems thinking" approach to sustainability. Political science students will face the challenges of global climate change and gain an understanding of the nature of

  10. Use of a simulation intervention to examine differences in nursing students' hand hygiene knowledge, beliefs, and behaviors. (United States)

    Konicki, Tara; Miller, Elaine


    Although hand hygiene remains an essential aspect of quality care, adherence to best patient safety practices continues to pose major challenges. The objectives of this study are to examine hand hygiene knowledge, beliefs, practices, perceived importance and behaviors using Social Cognitive Theory and simulation-based intervention. Participants were taken from a convenience sample of 131 undergraduate nursing students enrolled in a nursing fundamentals course at an urban university in the midwestern United States, and then randomly assigned to their respective groups. Using an experimental pretest-posttest design, control and intervention groups received the same lecture pertaining to hand hygiene and 3 data collection points where van de Mortel's Hand Hygiene Questionnaire (HHQ) was administered. In addition, the intervention group viewed a 6.5min video related to healthcare acquired infection and participated in 4 simulated situations requiring hand hygiene, based on World Health Organization guidelines. For all students, the hand hygiene technique was assessed through the use of Glo Germ, followed by handwashing and photography under ultraviolet light (posttest only). Image illumination was analyzed using image processing software. Microbiological sampling plates (pretest-posttest) were assessed quantitatively by colony counting. Study findings did not support differences in the intervention group for the 5 hypothesized relationships. Social desirability responding and negative item confusion were found to occur with the HHQ in the student population. There was a significant difference in the UV hand photographs, with students in the afternoon having lower values than students in the morning. Given the study results, there were no definitive educational recommendations to teach hand hygiene to nursing students. Future research should continue to further examine multi-focal modalities to enhance adherence to hand hygiene practices, as well as control for

  11. Molecular dynamics simulations of GPCR-cholesterol interaction: An emerging paradigm. (United States)

    Sengupta, Durba; Chattopadhyay, Amitabha


    G protein-coupled receptors (GPCRs) are the largest class of molecules involved in signal transduction across cell membranes and represent major targets in the development of novel drug candidates. Membrane cholesterol plays an important role in GPCR structure and function. Molecular dynamics simulations have been successful in exploring the effect of cholesterol on the receptor and a general consensus molecular view is emerging. We review here recent molecular dynamics studies at multiple resolutions highlighting the main features of cholesterol-GPCR interaction. Several cholesterol interaction sites have been identified on the receptor that are reminiscent of nonannular sites. These cholesterol hot-spots are highly dynamic and have a microsecond time scale of exchange with the bulk lipids. A few consensus sites (such as the CRAC site) have been identified that correspond to higher cholesterol interaction. Interestingly, high plasticity is observed in the modes of cholesterol interaction and several sites have been suggested to have high cholesterol occupancy. We therefore believe that these cholesterol hot-spots are indicative of 'high occupancy sites' rather than 'binding sites'. The results suggest that the energy landscape of cholesterol association with GPCRs corresponds to a series of shallow minima interconnected by low barriers. These specific interactions, along with general membrane effects, have been observed to modulate GPCR organization. Membrane cholesterol effects on receptor structure and organization, that in turn influences receptor cross-talk and drug efficacy, represent a new frontier in GPCR research. This article is part of a Special Issue entitled: Lipid-protein interactions. Guest Editors: Amitabha Chattopadhyay and Jean-Marie Ruysschaert. Copyright © 2015 Elsevier B.V. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Brett A McKinney


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

  13. Molecular dynamics simulations of interactions between energetic dust and plasma-facing materials

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Guo-jian, E-mail: [Institute of Plasma Physics Chinese Academy of Sciences, Hefei (China); Li, Xiao-chun; Xu, Qian; Yang, Zhong-shi [Hefei Center Physical Science and Technology, Hefei (China); Luo, Guang-nan [Institute of Plasma Physics Chinese Academy of Sciences, Hefei (China); Hefei Center Physical Science and Technology, Hefei (China); Hefei Science Center of CAS, Hefei (China)


    The interactions between dust and plasma-facing material (PFM) relate to the lifetime of PFM and impurity production. Series results have been obtained theoretically and experimentally but more detailed studies are needed. In present research, we investigate the evolution of kinetic, potential and total energy of plasma-facing material (PFM) in order to understand the dust/PFM interaction process. Three typical impacting energy are selected, i.e., 1, 10 and 100 keV/dust for low-, high- and hyper-energy impacting cases. For low impacting energy, dust particles stick on PFM surface without damaging it. Two typical time points exist and the temperature of PFM grows all the time but PFM structure experience a modifying process. Under high energy case, three typical points appear. The temperature curve fluctuates in the whole interaction process which indicates there are dust/PFM and kinetic/potential energy exchanges. In the hyper-energy case in present simulation, the violence dust/PFM interactions cause sputtering and crater investigating on energy evolution curves. We further propose the statistics of energy distribution. Results show that about half of impacting energy consumes on heating plasma-facing material meanwhile the other half on PFM structure deformation. Only a small proportion becomes kinetic energy of interstitial or sputtering atoms.

  14. Simulation study on exchange interaction and unique magnetization near ferromagnetic morphotropic phase boundary (United States)

    Wei, Songrui; Liao, Xiaoqi; Gao, Yipeng; Yang, Sen; Wang, Dong; Song, Xiaoping


    Extensive efforts have been made in searching enhanced functionalities near the so-called morphotropic phase boundaries (MPBs) in both ferroelectric and ferromagnetic materials. Due to the exchange anti-symmetry of the wave function of fermions, it is widely recognized that the exchange interaction plays a critical role in ferromagnetism. As a quantum effect, the exchange interaction is magnitudes larger than electric interaction, leading to a fundamental difference between ferroelectricity and ferromagnetism. In this paper, we establish an energetic model capturing the interplay among the anisotropy energy, magnetostatic energy and the exchange energy to investigate systematically the effects of the exchange energy on the behavior of the ferromagnetic MPB. For the first time, it is found that the exchange energy can narrow the width of MPB region in the composition temperature phase diagram for ferromagnetic MPB systems. As temperature increases, MPB region becomes wider because of the weakening of the exchange interaction. Our simulation results suggest that the exchange energy play a critical role on the unique behavior of ferromagnetic MPB, which is in contrast different from that of ferroelectric MPB.

  15. Detached eddy simulation of the rotor-stator interaction phenomenon in a moving cascade of airfoils (United States)

    Guardo, A.; Fontanals, A.; Coussirat, M.; Egusquiza, E.


    Flow inside turbomachinery is fairly complex in general, due to the geometry complexity and the intrinsic structure of the flow. Rotor-Stator Interaction (RSI) has a strong influence on the machine behavior, especially when the machine is operating in off-design conditions, where flow complexity increases due to the presence of boundary layer detachment influencing the general flow pattern and creating pressure pulses that can enhance the RSI behavior. These interactions can have a significant impact on the vibrational and acoustical characteristics of the machine. For gaining insight in the RSI characteristics and the behavior of a turbomachinery under this kind of flow interaction, in this work the RSI generated between a moving cascade of airfoils and fixed flat plate located downstream was studied by means of Computational Fluid Dynamics (CFD) using Detached Eddy Simulation (DES). The upstream boundary layer influence on the wake of the moving cascade, and the subsequent wake-boundary layer interaction between the cascade and a fixed flat plate downstream were obtained and compared against experimental and previous numerical results (obtained with Eddy Viscosity Models). Design and off-design conditions were modeled and a detailed comparison between them has been made. To analyze in detail the flow pattern, mean and fluctuating velocities were obtained and compared against experimental results. Furthermore, results concerning to turbulence intensity were compared against an experimental database.

  16. A Monte Carlo simulation for the field theory with quartic interaction

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Sergio Mittmann dos [Instituto Federal de Educacao, Ciencia e Tecnologia do Rio Grande do Sul (IFRS), Porto Alegre, RS (Brazil)


    Full text: In the work [1-S. M. Santos, B. E. J. Bodmann and A. T. Gomez, Um novo metodo computacional para a teoria de campos na rede: resultados preliminares, IV Escola do Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, 2002; and 2-S. M. Santos and B. E. J. Bodmann, Simulacao na rede de teorias de campos quanticos, XXVIII Congresso Nacional de Matematica Aplicada e Computacional (CNMAC), Sao Paulo, 2005], a computational method on the lattice was elaborated for the problem known as scalar field theory with quartic interaction (for instance, see: J. R. Klauder, Beyound conventional quantization, Cambridge: Cambridge University Press, 2000). This one introduced an algorithm, which allows the simulation of a given field theory and is independent of the lattice spacing, by redefining the fields and the parameters (the mass m and the coupling constant g). This kind of approach permits varying the dimension of the lattice without changing the computational complexity of the algorithm. A simulation was made using the Monte Carlo method, where the renormalized mass m{sub R}, the renormalized coupling constant g{sub R} and the two point correlation function were determined with success. In the present work, the genuine computational method is used for new simulations. Now, the Monte Carlo method is not used just for the simulation of the algorithm, like in [1, 2], but also for defining the adjust parameters (the mass and the coupling constant), introduced ad hoc in [1, 2]. This work presents the first simulations' outcomes, where best results that [1, 2] were determined, for the renormalized mass and the renormalized coupling constant. (author)

  17. Fluid-structure interaction simulations of the Fontan procedure using variable wall properties. (United States)

    Long, C C; Hsu, M-C; Bazilevs, Y; Feinstein, J A; Marsden, A L


    Children born with single ventricle heart defects typically undergo a staged surgical procedure culminating in a total cavopulmonary connection (TCPC) or Fontan surgery. The goal of this work was to perform physiologic, patient-specific hemodynamic simulations of two post-operative TCPC patients by using fluid-structure interaction (FSI) simulations. Data from two patients are presented, and post-op anatomy is reconstructed from MRI data. Respiration rate, heart rate, and venous pressures are obtained from catheterization data, and inflow rates are obtained from phase contrast MRI data and are used together with a respiratory model. Lumped parameter (Windkessel) boundary conditions are used at the outlets. We perform FSI simulations by using an arbitrary Lagrangian-Eulerian finite element framework to account for motion of the blood vessel walls in the TCPC. This study is the first to introduce variable elastic properties for the different areas of the TCPC, including a Gore-Tex conduit. Quantities such as wall shear stresses and pressures at critical locations are extracted from the simulation and are compared with pressure tracings from clinical data as well as with rigid wall simulations. Hepatic flow distribution and energy efficiency are also calculated and compared for all cases. There is little effect of FSI on pressure tracings, hepatic flow distribution, and time-averaged energy efficiency. However, the effect of FSI on wall shear stress, instantaneous energy efficiency, and wall motion is significant and should be considered in future work, particularly for accurate prediction of thrombus formation. Copyright © 2012 John Wiley & Sons, Ltd.

  18. Numerical simulations of interactions between Typhoon Choi-wan (0914) and the ocean (United States)

    Wada, A.; Cronin, M. F.; Sutton, A. J.; Kawai, Y.; Ishii, M.


    This study uses data collected by the Kuroshio Extension Observatory (KEO) mooring during the passage of Typhoon Choi-Wan (International designation 0914) to validate numerical simulations of the typhoon-ocean interactions and their effect on carbon dioxide uptake and outgassing conducted by an atmosphere-wave-ocean coupled model incorporating a carbon equilibrium model. The eye of the typhoon passed the KEO mooring, located at 32.3○N, 144.5○E, ~40 km to the southeast on 19 September 2009. The coupled model reasonably simulated the positions of Choi-wan and variation in observed sea-level pressure, although the simulated moving speed was slower than that of the best track when the typhoon passed near the KEO buoy. The slow translation and poor oceanic initial field appeared to cause the results of lower sea-surface temperature (SST), sea-surface salinity (SSS) and oceanic partial CO2 than those of observations. Better agreement was found with the grid point south of the buoy when the eye of the typhoon passed by the buoy three hours ago, where the initial SST and SSS were higher than observations and simulated dissolved inorganic carbon were relatively high compared with that at the buoy. A difference in surface-roughness-length schemes affects sea-level pressure, air temperature and surface wind asymmetry but little effect on the values of SST, SSS and oceanic partial CO2 variations. Therefore, simulation of the sudden variation of the air-sea partial CO2 appears to be more sensitive to the typhoon track, the intensity and oceanic initial field than the effect of ocean waves.

  19. Implementation of a web-based interactive virtual patient case simulation as a training and assessment tool for medical students. (United States)

    Oliven, A; Nave, R; Gilad, D; Barch, A


    Structured Clinical Examinations (OSCE) are resource intensive, not practical as teaching tools, and their reliability depends on evaluators. Computer-based case simulations ("virtual patients", VP) have been advocated as useful and reliable tools for teaching clinical skills and evaluating competence. We have developed an internet-based VP system designed both for practice and assessment of medical students. The system uses interactive dialogue with natural language processing, and is designed for history taking, evaluation of physical examination, including recognition of visual findings and heart and lung sounds, and ordering lab-and imaging tests. The system includes a practice modality that provides feedback, and a computerized OSCE. The reliability of our system was assessed over the last three years by comparing the clinical competence of medical students in similar VP and human OSCE. A total of 262 students were evaluated with both exam modalities. The correlation between the two exams scores was highly significant (p<0.001). Alpha Cronbach for the computerized exam was 0.82-0.89 in the 3 years, and was substantially higher than that of the conventional OSCE each year. We conclude that a computerized VP OSCE is a reliable examination tool, with the advantage of providing also a training modality.

  20. Ferrimagnetic/ferroelastic domain interactions in magnetite below the Verwey transition: Part II. Micromagnetic and image simulations

    DEFF Research Database (Denmark)

    Bryson, James F.J.; Kasama, Takeshi; Dunin-Borkowski, Rafal E.


    Micromagnetic simulations have been used to explore the interaction between ferrimagnetic domain walls (DWs) and ferroelastic twin walls (TWs) below the Verwey transition in magnetite (Fe3O4). Simulations were performed using a thin-foil geometry in order to replicate the domain patterns observed...

  1. The Impact of Computer Simulations as Interactive Demonstration Tools on the Performance of Grade 11 Learners in Electromagnetism (United States)

    Kotoka, Jonas; Kriek, Jeanne


    The impact of computer simulations on the performance of 65 grade 11 learners in electromagnetism in a South African high school in the Mpumalanga province is investigated. Learners did not use the simulations individually, but teachers used them as an interactive demonstration tool. Basic concepts in electromagnetism are difficult to understand…

  2. Developing a Tool Point Control Scheme for a Hydraulic Crane Using Interactive Real-time Dynamic Simulation

    DEFF Research Database (Denmark)

    Pedersen, Mikkel Melters; Hansen, Michael Rygaard; Ballebye, Morten


    This paper describes the implementation of an interactive real-time dynamic simulation model of a hydraulic crane. The user input to the model is given continuously via joystick and output is presented continuously in a 3D animation. Using this simulation model, a tool point control scheme...... is developed for the specific crane, considering the saturation phenomena of the system and practical implementation....

  3. The use of simulation in healthcare: from systems issues, to team building, to task training, to education and high stakes examinations. (United States)

    Orledge, Jeffrey; Phillips, William J; Murray, W Bosseau; Lerant, Anna


    Simulation in healthcare is becoming increasingly used. This review will spotlight some of the uses of simulation in healthcare training. Previously, evaluation of simulation training was typically from evaluations from trainees. Recent articles, however, have linked simulation training to actual patient outcomes and demonstrated skill retention up to 1 year. Objective measurements have demonstrated positive effects on healthcare education, have been successfully used in high stakes examinations, and have uncovered systems and patient safety issues. This article will review some recent studies showing how simulation can have a positive effect on patient outcomes and skill retention, uncover systems issues related to patient safety, and how simulation can be used in credentialing, and other high stakes examinations.

  4. Study of wave-particle interaction between fast Magnetosonic and energetic electrons based on numerical simulation (United States)

    Fu, S.


    There are many energetic electrons in the radiation belt of Earth. When the geomagnetic activity becomes stronger, the energy flux of energetic electrons will increase to more than ten times in the outer radiation belt, therefore it is very important to study how the energetic electrons generate and the lifetime of energetic electrons for space weather research. The acceleration of electrons in radiation belt is mainly depending on wave-particle interaction: the whistler mode chorus is the main driver for local acceleration mechanism, which could accelerate and loss energetic electrons; the geomagnetic pulsation ULF wave will cause energetic electron inward radial diffusion which will charge the electrons; recently observation results show us that the fast magnetosonic waves may also accelerate energetic electrons. For the reason that we try to study the wave-particle interaction between fast Magnetosonic and energetic electrons based on numerical simulation, in which the most important past is at the storm time the combination of highly warped Earth magnetic field and fast magnetosonic wave field will be applied for the electromagnetic environment of moving test particles. The energy, pitch angle and cross diffusion coefficients will be calculated respectively in this simulation to study how the electrons receive energy from fast magnetosonic wave. The diffusion coefficients within different dipole Earth magnetic field and non-dipole storm magnetic field are compared, while dynamics of electrons at selected initial energys are shown in our study.

  5. Wildfire Emissions and Their Interaction with Urban and Rural Pollution: Data and Simulations (United States)

    Singh, H. B.


    In recent years NASA has conducted a series of airborne campaigns (e. g. SEAC4RS*, ARCTAS, INTEX-A/B) over North America using an instrumented DC-8 aircraft equipped to measure a very large number of gaseous and aerosol constituents including several unique tracers. In these campaigns wild fires were extensively sampled near source as well as downwind after aging. The data provided detailed information on the composition and chemistry of fire emissions under a variety of atmospheric conditions as well as their interactions with rural and urban air pollution. Major fires studied including the California Rim fire in 2013 (SEAC4RS), the 2008 California wildfires (ARCTAS), and the Alaskan fires downwind over eastern US (INTEX-A). Although some fire plumes contained virtually no O3 enhancement, others showed significant ozone formation. Over Los Angeles, the highest O3 mixing ratios were observed in fire influenced urban air masses. Attempts to simulate these interactions using state of the art models were only minimally successful and indicated several shortcomings in simulating fire emission influences on urban smog formation. A variety of secondary oxidation products (e. g. O3, PAN, HCHO) were substantially underestimated. We will discuss the data collected in fire influenced air masses and their potential air quality implications.

  6. Engaging Undergraduate Math Majors in Geoscience Research using Interactive Simulations and Computer Art (United States)

    Matott, L. S.; Hymiak, B.; Reslink, C. F.; Baxter, C.; Aziz, S.


    As part of the NSF-sponsored 'URGE (Undergraduate Research Group Experiences) to Compute' program, Dr. Matott has been collaborating with talented Math majors to explore the design of cost-effective systems to safeguard groundwater supplies from contaminated sites. Such activity is aided by a combination of groundwater modeling, simulation-based optimization, and high-performance computing - disciplines largely unfamiliar to the students at the outset of the program. To help train and engage the students, a number of interactive and graphical software packages were utilized. Examples include: (1) a tutorial for exploring the behavior of evolutionary algorithms and other heuristic optimizers commonly used in simulation-based optimization; (2) an interactive groundwater modeling package for exploring alternative pump-and-treat containment scenarios at a contaminated site in Billings, Montana; (3) the R software package for visualizing various concepts related to subsurface hydrology; and (4) a job visualization tool for exploring the behavior of numerical experiments run on a large distributed computing cluster. Further engagement and excitement in the program was fostered by entering (and winning) a computer art competition run by the Coalition for Academic Scientific Computation (CASC). The winning submission visualizes an exhaustively mapped optimization cost surface and dramatically illustrates the phenomena of artificial minima - valley locations that correspond to designs whose costs are only partially optimal.

  7. Building interactive virtual environments for simulated training in medicine using VRML and Java/JavaScript. (United States)

    Korocsec, D; Holobar, A; Divjak, M; Zazula, D


    Medicine is a difficult thing to learn. Experimenting with real patients should not be the only option; simulation deserves a special attention here. Virtual Reality Modelling Language (VRML) as a tool for building virtual objects and scenes has a good record of educational applications in medicine, especially for static and animated visualisations of body parts and organs. However, to create computer simulations resembling situations in real environments the required level of interactivity and dynamics is difficult to achieve. In the present paper we describe some approaches and techniques which we used to push the limits of the current VRML technology further toward dynamic 3D representation of virtual environments (VEs). Our demonstration is based on the implementation of a virtual baby model, whose vital signs can be controlled from an external Java application. The main contributions of this work are: (a) outline and evaluation of the three-level VRML/Java implementation of the dynamic virtual environment, (b) proposal for a modified VRML Timesensor node, which greatly improves the overall control of system performance, and (c) architecture of the prototype distributed virtual environment for training in neonatal resuscitation comprising the interactive virtual newborn, active bedside monitor for vital signs and full 3D representation of the surgery room.

  8. Molecular Dynamics Simulation to Investigate the Interaction of Asphaltene and Oxide in Aggregate

    Directory of Open Access Journals (Sweden)

    Rui Li


    Full Text Available The asphalt-aggregate interface interaction (AAI plays a significant role in the overall performances of asphalt mixture, which is caused due to the complicated physicochemical processes and is influenced by various factors, including the acid-base property of aggregates. In order to analyze the effects of the chemical constitution of aggregate on the AAI, the average structure C65H74N2S2 is selected to represent the asphaltene in asphalt and magnesium oxide (MgO, calcium oxide (CaO, aluminium sesquioxide (Al2O3, and silicon dioxide (SiO2 are selected to represent the major oxides in aggregate. The molecular models are established for asphaltene and the four oxides, respectively, and the molecular dynamics (MD simulation was conducted for the four kinds of asphaltene-oxide system at different temperatures. The interfacial energy in MD simulation is calculated to evaluate the AAI, and higher value means better interaction. The results show that interfacial energy between asphaltene and oxide reaches the maximum value at 25°C and 80°C and the minimum value at 40°C. In addition, the interfacial energy between asphaltene and MgO was found to be the greatest, followed by CaO, Al2O3, and SiO2, which demonstrates that the AAI between asphalt and alkaline aggregates is better than acidic aggregates.

  9. Aspects of solar wind interaction with Mars: comparison of fluid and hybrid simulations

    Directory of Open Access Journals (Sweden)

    N. V. Erkaev


    Full Text Available Mars has no global intrinsic magnetic field, and consequently the solar wind plasma interacts directly with the planetary ionosphere. The main factors of this interaction are: thermalization of plasma after the bow shock, ion pick-up process, and the magnetic barrier effect, which results in the magnetic field enhancement in the vicinity of the obstacle. Results of ideal magnetohydrodynamic and hybrid simulations are compared in the subsolar magnetosheath region. Good agreement between the models is obtained for the magnetic field and plasma parameters just after the shock front, and also for the magnetic field profiles in the magnetosheath. Both models predict similar positions of the proton stoppage boundary, which is known as the ion composition boundary. This comparison allows one to estimate applicability of magnetohydrodynamics for Mars, and also to check the consistency of the hybrid model with Rankine-Hugoniot conditions at the bow shock. An additional effect existing only in the hybrid model is a diffusive penetration of the magnetic field inside the ionosphere. Collisions between ions and neutrals are analyzed as a possible physical reason for the magnetic diffusion seen in the hybrid simulations.

  10. Binding and discerning interactions of PTP1B allosteric inhibitors: novel insights from molecular dynamics simulations. (United States)

    Shinde, Ranajit Nivrutti; Sobhia, M Elizabeth


    The α7 helix is either disordered or missing in the three co-crystal structures of allosteric inhibitors with protein tyrosine phosphatase 1B (PTP1B). It was modeled in each complex using the open form of PTP1B structure and studied using molecular dynamics (MD) simulations for 25 ns. B-factor analysis of the residues sheds light on its disordered nature in the co-crystal structures. Further, the ability of inhibitors to act as allosteric inhibitor was studied and established using novel hydrogen bond criteria. The MD simulations were utilized to determine the relative importance of electrostatic and hydrophobic component in to the binding of inhibitors. It was revealed that the hydrophobic interactions predominantly drive the molecular recognition of these inhibitors. Per residue energy decomposition analysis attributed dissimilar affinities of three inhibitors to the several hydrogen bonds and non-bonded interactions. Among the secondary structure elements that surround the allosteric site, helices α6, α7 and loop α6-α7 were notorious in providing variable affinities to the inhibitors. A novel hydrophobic pocket lined by the α7 helix residues Val287, Asn289 and Trp291 was identified in the allosteric site. This study provides useful insights for the rational design of high affinity PTP1B allosteric inhibitors. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. Using Multiple Lenses to Examine the Development of Beginning Biology Teachers' Pedagogical Content Knowledge for Teaching Natural Selection Simulations (United States)

    Sickel, Aaron J.; Friedrichsen, Patricia


    Pedagogical content knowledge (PCK) has become a useful construct to examine science teacher learning. Yet, researchers conceptualize PCK development in different ways. The purpose of this longitudinal study was to use three analytic lenses to understand the development of three beginning biology teachers' PCK for teaching natural selection simulations. We observed three early-career biology teachers as they taught natural selection in their respective school contexts over two consecutive years. Data consisted of six interviews with each participant. Using the PCK model developed by Magnusson et al. (1999), we examined topic-specific PCK development utilizing three different lenses: (1) expansion of knowledge within an individual knowledge base, (2) integration of knowledge across knowledge bases, and (3) knowledge that explicitly addressed core concepts of natural selection. We found commonalities across the participants, yet each lens was also useful to understand the influence of different factors (e.g., orientation, subject matter preparation, and the idiosyncratic nature of teacher knowledge) on PCK development. This multi-angle approach provides implications for considering the quality of beginning science teachers' knowledge and future research on PCK development. We conclude with an argument that explicitly communicating lenses used to understand PCK development will help the research community compare analytic approaches and better understand the nature of science teacher learning.

  12. Design, development, and evaluation of a second generation interactive Simulator for Engineering Ethics Education (SEEE2). (United States)

    Alfred, Michael; Chung, Christopher A


    This paper describes a second generation Simulator for Engineering Ethics Education. Details describing the first generation activities of this overall effort are published in Chung and Alfred (Sci Eng Ethics 15:189-199, 2009). The second generation research effort represents a major development in the interactive simulator educational approach. As with the first generation effort, the simulator places students in first person perspective scenarios involving different types of ethical situations. Students must still gather data, assess the situation, and make decisions. The approach still requires students to develop their own ability to identify and respond to ethical engineering situations. However, were as, the generation one effort involved the use of a dogmatic model based on National Society of Professional Engineers' Code of Ethics, the new generation two model is based on a mathematical model of the actual experiences of engineers involved in ethical situations. This approach also allows the use of feedback in the form of decision effectiveness and professional career impact. Statistical comparisons indicate a 59 percent increase in overall knowledge and a 19 percent improvement in teaching effectiveness over an Internet Engineering Ethics resource based approach.

  13. Exponentially more precise quantum simulation of fermions in the configuration interaction representation (United States)

    Babbush, Ryan; Berry, Dominic W.; Sanders, Yuval R.; Kivlichan, Ian D.; Scherer, Artur; Wei, Annie Y.; Love, Peter J.; Aspuru-Guzik, Alán


    We present a quantum algorithm for the simulation of molecular systems that is asymptotically more efficient than all previous algorithms in the literature in terms of the main problem parameters. As in Babbush et al (2016 New Journal of Physics 18, 033032), we employ a recently developed technique for simulating Hamiltonian evolution using a truncated Taylor series to obtain logarithmic scaling with the inverse of the desired precision. The algorithm of this paper involves simulation under an oracle for the sparse, first-quantized representation of the molecular Hamiltonian known as the configuration interaction (CI) matrix. We construct and query the CI matrix oracle to allow for on-the-fly computation of molecular integrals in a way that is exponentially more efficient than classical numerical methods. Whereas second-quantized representations of the wavefunction require \\widetilde{{ O }}(N) qubits, where N is the number of single-particle spin-orbitals, the CI matrix representation requires \\widetilde{{ O }}(η ) qubits, where η \\ll N is the number of electrons in the molecule of interest. We show that the gate count of our algorithm scales at most as \\widetilde{{ O }}({η }2{N}3t).

  14. Large Eddy Simulations of the Vortex-Flame Interaction in a Turbulent Swirl Burner (United States)

    Lu, Zhen; Elbaz, Ayman M.; Hernandez Perez, Francisco E.; Roberts, William L.; Im, Hong G.


    A series of swirl-stabilized partially premixed flames are simulated using large eddy simulation (LES) along with the flamelet/progress variable (FPV) model for combustion. The target burner has separate and concentric methane and air streams, with methane in the center and the air flow swirled through the tangential inlets. The flame is lifted in a straight quarl, leading to a partially premixed state. By fixing the swirl number and air flow rate, the fuel jet velocity is reduced to study flame stability as the flame approaches the lean blow-off limit. Simulation results are compared against measured data, yielding a generally good agreement on the velocity, temperature, and species mass fraction distributions. The proper orthogonal decomposition (POD) method is applied on the velocity and progress variable fields to analyze the dominant unsteady flow structure, indicating a coupling between the precessing vortex core (PVC) and the flame. The effects of vortex-flame interactions on the stabilization of the lifted swirling flame are also investigated. For the stabilization of the lifted swirling flame, the effects of convection, enhanced mixing, and flame stretching introduced by the PVC are assessed based on the numerical results. This research work was sponsored by King Abdullah University of Science and Technology (KAUST) and used computational resources at KAUST Supercomputing Laboratory.

  15. In-situ electrochemical study of interaction of tribology and corrosion in artificial hip prosthesis simulators. (United States)

    Yan, Yu; Dowson, Duncan; Neville, Anne


    The second generation Metal-on-Metal (MoM) hip replacements have been considered as an alternative to commonly used Polyethylene-on-Metal (PoM) joint prostheses due to polyethylene wear debris induced osteolysis. However, the role of corrosion and the biofilm formed under tribological contact are still not fully understood. Enhanced metal ion concentrations have been reported widely from hair, blood and urine samples of patients who received metal hip replacements and in isolated cases when abnormally high levels have caused adverse local tissue reactions. An understanding of the origin of metal ions is really important in order to design alloys for reduced ion release. Reciprocating pin-on-plate wear tester is a standard instrument to assess the interaction of corrosion and wear. However, more realistic hip simulator can provide a better understanding of tribocorrosion process for hip implants. It is very important to instrument the conventional hip simulator to enable electrochemical measurements. In this study, simple reciprocating pin-on-plate wear tests and hip simulator tests were compared. It was found that metal ions originated from two sources: (a) a depassivation of the contacting surfaces due to tribology (rubbing) and (b) corrosion of nano-sized wear particles generated from the contacting surfaces. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Experimental simulation: using generative modelling and palaeoecological data to understand human-environment interactions

    Directory of Open Access Journals (Sweden)

    George Perry


    Full Text Available The amount of palaeoecological information available continues to grow rapidly, providing improved descriptions of the dynamics of past ecosystems and enabling them to be seen from new perspectives. At the same time, there has been concern over whether palaeoecological enquiry needs to move beyond descriptive inference to a more hypothesis-focussed or experimental approach; however, the extent to which conventional hypothesis-driven scientific frameworks can be applied to historical contexts (i.e., the past is the subject of ongoing debate. In other disciplines concerned with human-environment interactions, including physical geography and archaeology, there has been growing use of generative simulation models, typified by agent-based approaches. Generative modelling encourages counter-factual questioning (what if…?, a mode of argument that is particularly important in systems and time-periods, such as the Holocene and now the Anthropocene, where the effects of humans and other biophysical processes are deeply intertwined. However, palaeoecologically focused simulation of the dynamics of the ecosystems of the past either seems to be conducted to assess the applicability of some model to the future or treats humans simplistically as external forcing factors. In this review we consider how generative simulation-modelling approaches could contribute to our understanding of past human-environment interactions. We consider two key issues: the need for null models for understanding past dynamics and the need to be able learn more from pattern-based analysis. In this light, we argue that there is considerable scope for palaeocology to benefit from developments in generative models and their evaluation. We discuss the view that simulation is a form of experiment and, by using case studies, consider how the many patterns available to palaeoecologists can support model evaluation in a way that moves beyond simplistic pattern-matching and how such models

  17. Simulation technique for slurries interacting with moving parts and deformable solids with applications (United States)

    Mutabaruka, Patrick; Kamrin, Ken


    A numerical method for particle-laden fluids interacting with a deformable solid domain and mobile rigid parts is proposed and implemented in a full engineering system. The fluid domain is modeled with a lattice Boltzmann representation, the particles and rigid parts are modeled with a discrete element representation, and the deformable solid domain is modeled using a Lagrangian mesh. The main issue of this work, since separately each of these methods is a mature tool, is to develop coupling and model-reduction approaches in order to efficiently simulate coupled problems of this nature, as in various geological and engineering applications. The lattice Boltzmann method incorporates a large eddy simulation technique using the Smagorinsky turbulence model. The discrete element method incorporates spherical and polyhedral particles for stiff contact interactions. A neo-Hookean hyperelastic model is used for the deformable solid. We provide a detailed description of how to couple the three solvers within a unified algorithm. The technique we propose for rubber modeling/coupling exploits a simplification that prevents having to solve a finite-element problem at each time step. We also developed a technique to reduce the domain size of the full system by replacing certain zones with quasi-analytic solutions, which act as effective boundary conditions for the lattice Boltzmann method. The major ingredients of the routine are separately validated. To demonstrate the coupled method in full, we simulate slurry flows in two kinds of piston valve geometries. The dynamics of the valve and slurry are studied and reported over a large range of input parameters.

  18. Verbal communication of students with high patient-physician interaction scores in a clinical performance examination assessed by standardized patients. (United States)

    Roh, HyeRin; Park, Kyung Hye; Park, Song Yi


    Standardized patients (SPs) tend to rate medical students' communication skills subjectively and comprehensively, in contrast to such objective skill set defined in the clinical performance examination (CPX). Meanwhile, medical school instructors have a different approach in their evaluation of students' communication skills. We aim to analyze medical students' verbal communication skills using objective methods, and to determine the contributing factors of a patient-physician interaction (PPI) score. Students with high- and low-ranking scores for PPI in CPX were selected. The Roter interaction analysis system was used to compare verbal communication behaviors of the students and SPs. Patient-centeredness scores (PCSs), physician's verbal dominance, and number of utterances were compared between the two groups. PCSs and physician's verbal dominance had no difference between the groups. The number of utterances during the limited time of 5 minutes of CPX was higher for the high-ranking students. They tended to employ more paraphrase/check for understanding, and closed questions for psychosocial state and open questions for medical condition. The SPs interviewed by high-ranking students gave more medical information and requested for more services. In the case of the routine checkup, smooth conversations with more frequent utterances were detected in the high-ranking students. More medical information exchange and requests for services by SPs were higher for the high-ranking students. Medical communication instructors should keep in mind that our results could be indicators of a high PPI score.

  19. Complementary or competing climates? Examining the interactive effect of service and ethical climates on company-level financial performance. (United States)

    Myer, Adam T; Thoroughgood, Christian N; Mohammed, Susan


    By bending rules to please their customers, companies with high service climates may be less ethical but ultimately more profitable. In this article, we pose the question of whether being ethical comes at a cost to profits in customer-oriented firms. Despite the organizational reality that multiple climates coexist at a given time, research has largely ignored these types of questions, and the simultaneous analysis of multiple climate dimensions has received little empirical attention to date. Given their scientific and practical importance, this study tested complementary and conflicting perspectives regarding interactions between service (outcome-focused) and ethical (process-focused) climates on company-level financial performance. Drawing on a sample of 16,862 medical sales representatives spread across 77 subsidiary companies of a large multinational corporation in the health care product industry, we found support for a complementary view. More precisely, results revealed that profitability was enhanced, not diminished, in service-oriented firms that also stressed the importance of ethics. Results suggest studying the interactive effects of multiple climates is a more fruitful approach than examining main effects alone. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  20. An interactive system for creating object models from range data based on simulated annealing

    Energy Technology Data Exchange (ETDEWEB)

    Hoff, W.A.; Hood, F.W.; King, R.H. [Colorado School of Mines, Golden, CO (United States). Center for Robotics and Intelligent Systems


    In hazardous applications such as remediation of buried waste and dismantlement of radioactive facilities, robots are an attractive solution. Sensing to recognize and locate objects is a critical need for robotic operations in unstructured environments. An accurate 3-D model of objects in the scene is necessary for efficient high level control of robots. Drawing upon concepts from supervisory control, the authors have developed an interactive system for creating object models from range data, based on simulated annealing. Site modeling is a task that is typically performed using purely manual or autonomous techniques, each of which has inherent strengths and weaknesses. However, an interactive modeling system combines the advantages of both manual and autonomous methods, to create a system that has high operator productivity as well as high flexibility and robustness. The system is unique in that it can work with very sparse range data, tolerate occlusions, and tolerate cluttered scenes. The authors have performed an informal evaluation with four operators on 16 different scenes, and have shown that the interactive system is superior to either manual or automatic methods in terms of task time and accuracy.