WorldWideScience

Sample records for range process simulation

  1. SIMULATION OF LOGISTICS PROCESSES

    Directory of Open Access Journals (Sweden)

    Yu. Taranenko

    2016-08-01

    Full Text Available The article deals with the theoretical basis of the simulation. The study shows the simulation of logistic processes in industrial countries is an integral part of many economic projects aimed at the creation or improvement of logistics systems. The paper was used model Beer Game for management of logistics processes in the enterprise. The simulation model implements in AnyLogic package. AnyLogic product allows us to consider the logistics processes as an integrated system, which allows reaching better solutions. Logistics process management involves pooling the sales market, production and distribution to ensure the temporal level of customer service at the lowest cost overall. This made it possible to conduct experiments and to determine the optimal size of the warehouse at the lowest cost.

  2. Monte Carlo simulation of relaxation processes in solid disordered neon under irradiation with photons in the energy range of 4-400 Ry. Role of the cascade decay relaxation processes

    Science.gov (United States)

    Kochur, Andrei G.; Chaynikov, Alexander P.; Yavna, Victor A.

    2017-11-01

    The processes in disordered solid neon irradiated with photons in the energy range of 4-400 Ry are studied using detailed Monte Carlo simulations taking into account cascade relaxation of ionized atoms. Trajectories of all secondary electrons and photons inside a spherical zone around the site of initial photoionization are analyzed. Energy absorbed in the zone and its distribution within the zone, distributions of concentrations of secondary inelastic processes, spectra of electrons and photons, and mean numbers of final ions are calculated. Secondary electrons, including those produced by cascade relaxation, are found to be the principal producers of inelastic processes. Cascade relaxation of ionized atoms is shown to be one of the crucial mechanisms in the effect of ionizing radiation on matter.

  3. Perfect simulation of Hawkes processes

    DEFF Research Database (Denmark)

    Møller, Jesper; Rasmussen, Jakob Gulddahl

    their branching and conditional independence structure, useful approximations of the distribution function for the length of a cluster are derived. This is used to construct upper and lower processes for the perfect simulation algorithm. Examples of applications and empirical results are presented.......This article concerns a perfect simulation algorithm for unmarked and marked Hawkes processes. The usual stratihtforward simulation algorithm suffers from edge effects, whereas our perfect simulation algorithm does not. By viewing Hawkes processes as Poisson cluster processes and using...

  4. Multi-purpose process simulators

    Directory of Open Access Journals (Sweden)

    Ommund Øgård

    1997-04-01

    Full Text Available The first part of this paper describes a multi-purpose dynamic simulator for the Heidrun oil production plant. The simulator integrates a commercial dynamic simulation model with the actual process control system to enable dynamic simulation, control system verification and operator training within the same framework and based on the same models and configuration data. The control system configuration can be imported directly into the simulator. This simplifies simulator maintenance and ensure consistency between the simulator and the real plant. The entire system runs on standard Unix work stations. The simulator has so far been used for initial operator training, control system verification and controller tuning.

  5. Perfect simulation of Hawkes processes

    DEFF Research Database (Denmark)

    Møller, Jesper; Rasmussen, Jakob Gulddahl

    2005-01-01

    their branching and conditional independence structures, useful approximations of the distribution function for the length of a cluster are derived. This is used to construct upper and lower processes for the perfect simulation algorithm. A tail-lightness condition turns out to be of importance......Our objective is to construct a perfect simulation algorithm for unmarked and marked Hawkes processes. The usual straightforward simulation algorithm suffers from edge effects, whereas our perfect simulation algorithm does not. By viewing Hawkes processes as Poisson cluster processes and using...

  6. Approximate simulation of Hawkes processes

    DEFF Research Database (Denmark)

    Møller, Jesper; Rasmussen, Jakob Gulddahl

    2006-01-01

    Hawkes processes are important in point process theory and its applications, and simulation of such processes are often needed for various statistical purposes. This article concerns a simulation algorithm for unmarked and marked Hawkes processes, exploiting that the process can be constructed...... as a Poisson cluster process. The algorithm suffers from edge effects but is much faster than the perfect simulation algorithm introduced in our previous work Møller and Rasmussen (2004). We derive various useful measures for the error committed when using the algorithm, and we discuss various empirical...... results for the algorithm compared with perfect simulations. Extensions of the algorithm and the results to more general types of marked point processes are also discussed....

  7. Stochastic processes and long range dependence

    CERN Document Server

    Samorodnitsky, Gennady

    2016-01-01

    This monograph is a gateway for researchers and graduate students to explore the profound, yet subtle, world of long-range dependence (also known as long memory). The text is organized around the probabilistic properties of stationary processes that are important for determining the presence or absence of long memory. The first few chapters serve as an overview of the general theory of stochastic processes which gives the reader sufficient background, language, and models for the subsequent discussion of long memory. The later chapters devoted to long memory begin with an introduction to the subject along with a brief history of its development, followed by a presentation of what is currently the best known approach, applicable to stationary processes with a finite second moment. The book concludes with a chapter devoted to the author’s own, less standard, point of view of long memory as a phase transition, and even includes some novel results. Most of the material in the book has not previously been publis...

  8. Approximate simulation of Hawkes processes

    DEFF Research Database (Denmark)

    Møller, Jesper; Rasmussen, Jakob Gulddahl

    This article concerns a simulation algorithm for unmarked and marked Hawkes processes. The algorithm suffers from edge effects but is much faster than the perfect simulation algorithm introduced in our previous work. We derive various useful measures for the error committed when using the algorithm...

  9. Simulating the Commander's Decision Process

    National Research Council Canada - National Science Library

    Kovalchik, Joseph G; Labin, Jonathan W; Rosenlof, Eric R

    2007-01-01

    ... * Commander Federate simulates the human decision process by employing -- A fuzzy expert system to set warfare priorities either by time or event and provides inter-warfare area conflict resolution...

  10. Image seeker simulation for short-range surface-to-surface missile

    Science.gov (United States)

    Jin, Sang-Hun; Kang, Ho-Gyun

    2007-04-01

    This paper presents an image seeker simulation including image processing, servo control, target model, and missile trajectory. We propose a software architecture for a seeker embedded computer. It makes core processing algorithms including image processing reusable at the source level through multiple platforms. The embedded software simulator implemented in C/C++, the servo control simulator implemented in Matlab, and the integrated simulator combined the both simulators based on Windows Component Object Module (COM) technology is presented. The integrated simulation enables developers to practice an interactive study between image processing and servo control about missions including lock-on and target tracking. The implemented simulator can be operated in low cost computer systems. This can be used to algorithm development and analysis at the design, implementation, and evaluation. Simulation examples for a short range ground-to-ground missile seeker are presented.

  11. Computer simulation of nonequilibrium processes

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, D.C.

    1985-07-01

    The underlying concepts of nonequilibrium statistical mechanics, and of irreversible thermodynamics, will be described. The question at hand is then, how are these concepts to be realize in computer simulations of many-particle systems. The answer will be given for dissipative deformation processes in solids, on three hierarchical levels: heterogeneous plastic flow, dislocation dynamics, an molecular dynamics. Aplication to the shock process will be discussed.

  12. Stochastic Simulation of Process Calculi for Biology

    Directory of Open Access Journals (Sweden)

    Andrew Phillips

    2010-10-01

    Full Text Available Biological systems typically involve large numbers of components with complex, highly parallel interactions and intrinsic stochasticity. To model this complexity, numerous programming languages based on process calculi have been developed, many of which are expressive enough to generate unbounded numbers of molecular species and reactions. As a result of this expressiveness, such calculi cannot rely on standard reaction-based simulation methods, which require fixed numbers of species and reactions. Rather than implementing custom stochastic simulation algorithms for each process calculus, we propose to use a generic abstract machine that can be instantiated to a range of process calculi and a range of reaction-based simulation algorithms. The abstract machine functions as a just-in-time compiler, which dynamically updates the set of possible reactions and chooses the next reaction in an iterative cycle. In this short paper we give a brief summary of the generic abstract machine, and show how it can be instantiated with the stochastic simulation algorithm known as Gillespie's Direct Method. We also discuss the wider implications of such an abstract machine, and outline how it can be used to simulate multiple calculi simultaneously within a common framework.

  13. Computerized simulation of converter process

    Energy Technology Data Exchange (ETDEWEB)

    Jalkanen, H.; Suomi, M.L.; Wallgren, M. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Metallurgy

    1996-12-31

    Converter process is essentially an oxidising refining process aiming in addition to (1) the primary refining action, decarburisation of high carbon iron melt, also to (2) maximal elimination of impurity elements, especially silicon, phosphorus and sulphur, (3) melting of substantial amounts of scrap using the extra heat released in oxidation reactions and (4) to exact final steel temperature control, optimal for further treatments. `Quantitative modelling of such a complex non-stationary chemical process as oxygen converting necessitates extensive formulation of chemical and thermal evolution of the process in connection with the technological properties of the reactor and the process control measures. A comprehensive converter simulation program like CONSIM-3. 1 and its preceding versions that is based on the theoretical and practical knowledge on the process can be used for (1) educating specialists and smelter personnel, (2) planning of the blowing programs, (3) developing and testing of process control systems and after some elaboration and restructuring (4) it can be integrated to static or dynamic process control systems. (orig.) SULA 2 Research Programme; 10 refs.

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

    Directory of Open Access Journals (Sweden)

    Marmelat Vivien

    2011-12-01

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

  15. Comparison of range migration correction algorithms for range-Doppler processing

    Science.gov (United States)

    Uysal, Faruk

    2017-07-01

    The next generation digital radars are able to provide high-range resolution by the advancement of radar hardware technologies. These systems take advantage of coherent integration and Doppler processing technique to increase the target's signal-to-noise ratio. Due to the high-range resolution (small range cells) and fast target motion, a target migrates through multiple range cells within a coherent processing interval. Range cell migration (also known as range walk) occurs and degrades the coherent integration gain. There are many approaches in the literature to correct these unavoidable effects and focus the target in the range-Doppler domain. We demonstrate some of these methods on an operational frequency-modulated continuous-wave (FMCW) radar and point out practical issues in the application.

  16. Geographical ranges in macroecology: Processes, patterns and implications

    DEFF Research Database (Denmark)

    Borregaard, Michael Krabbe

    , are distributed over the entire Earth. Species’ ranges are one of the basic units of the science of macroecology, which deals with patterns in the distribution of life on Earth. An example of such patterns is the large geographic variation in species richness between areas. These patterns are closely linked......, I draw upon a wide range of approaches, including statistical comparative analysis, computer simulations and null models. The core of the thesis is constituted by five independent scientific articles. These chapters fall naturally within two thematic groups: The first group consists of articles...... that investigate how ecology and evolution determine species’ ranges. The central paper in this group is a large review article about one of the best described patterns in ecology: That species with large ranges tend to also be very locally abundant within their range. In the article I review the potential causes...

  17. A new process simulator for recovery boilers

    Energy Technology Data Exchange (ETDEWEB)

    Lysen, C. [Kvaerner Pulping Technologies, Karlstad (Sweden)

    1995-12-31

    A recovery boiler process simulator, built as an educational tool for operators and process engineers, was presented. Each simulator is adapted to one specific boiler, which means that configuration and capacities of equipment like superheaters, economizers, air heaters, fans, pumps, etc. all reflect the boiler being simulated. All maneuverable items, such as controllers, valves, pumps, etc., are simulated in order to illustrate process dynamics and interrelations between different variables (plant start-ups and shut-downs, fault detection, safety procedures, and handling of disturbances). 4 figs.

  18. Design of penicillin fermentation process simulation system

    Science.gov (United States)

    Qi, Xiaoyu; Yuan, Zhonghu; Qi, Xiaoxuan; Zhang, Wenqi

    2011-10-01

    Real-time monitoring for batch process attracts increasing attention. It can ensure safety and provide products with consistent quality. The design of simulation system of batch process fault diagnosis is of great significance. In this paper, penicillin fermentation, a typical non-linear, dynamic, multi-stage batch production process, is taken as the research object. A visual human-machine interactive simulation software system based on Windows operation system is developed. The simulation system can provide an effective platform for the research of batch process fault diagnosis.

  19. Numerical Simulations of Granular Processes

    Science.gov (United States)

    Richardson, Derek C.; Michel, Patrick; Schwartz, Stephen R.; Ballouz, Ronald-Louis; Yu, Yang; Matsumura, Soko

    2014-11-01

    Spacecraft images and indirect observations including thermal inertia measurements indicate most small bodies have surface regolith. Evidence of granular flow is also apparent in the images. This material motion occurs in very low gravity, therefore in a completely different gravitational environment than on the Earth. Understanding and modeling these motions can aid in the interpretation of imaged surface features that may exhibit signatures of constituent material properties. Also, upcoming sample-return missions to small bodies, and possible future manned missions, will involve interaction with the surface regolith, so it is important to develop tools to predict the surface response. We have added new capabilities to the parallelized N-body gravity tree code pkdgrav [1,2] that permit the simulation of granular dynamics, including multi-contact physics and friction forces, using the soft-sphere discrete-element method [3]. The numerical approach has been validated through comparison with laboratory experiments (e.g., [3,4]). Ongoing and recently completed projects include: impacts into granular materials using different projectile shapes [5]; possible tidal resurfacing of asteroid Apophis during its 2029 encounter [6]; the Brazil-nut effect in low gravity [7]; and avalanche modeling.Acknowledgements: DCR acknowledges NASA (grants NNX08AM39G, NNX10AQ01G, NNX12AG29G) and NSF (AST1009579). PM acknowledges the French agency CNES. SRS works on the NEOShield Project funded under the European Commission’s FP7 program agreement No. 282703. SM acknowledges support from the Center for Theory and Computation at U Maryland and the Dundee Fellowship at U Dundee. Most simulations were performed using the YORP cluster in the Dept. of Astronomy at U Maryland and on the Deepthought High-Performance Computing Cluster at U Maryland.References: [1] Richardson, D.C. et al. 2000, Icarus 143, 45; [2] Stadel, J. 2001, Ph.D. Thesis, U Washington; [3] Schwartz, S.R. et al. 2012, Gran

  20. Topographic laser ranging and scanning principles and processing

    CERN Document Server

    Shan, Jie

    2008-01-01

    A systematic, in-depth introduction to theories and principles of Light Detection and Ranging (LiDAR) technology is long overdue, as it is the most important geospatial data acquisition technology to be introduced in recent years. An advanced discussion, this text fills the void.Professionals in fields ranging from geology, geography and geoinformatics to physics, transportation, and law enforcement will benefit from this comprehensive discussion of topographic LiDAR principles, systems, data acquisition, and data processing techniques. The book covers ranging and scanning fundamentals, and broad, contemporary analysis of airborne LiDAR systems, as well as those situated on land and in space. The authors present data collection at the signal level in terms of waveforms and their properties; at the system level with regard to calibration and georeferencing; and at the data level to discuss error budget, quality control, and data organization. They devote the bulk of the book to LiDAR data processing and inform...

  1. Aqueous Electrolytes: Model Parameters and Process Simulation

    DEFF Research Database (Denmark)

    Thomsen, Kaj

    This thesis deals with aqueous electrolyte mixtures. The Extended UNIQUAC model is being used to describe the excess Gibbs energy of such solutions. Extended UNIQUAC parameters for the twelve ions Na+, K+, NH4+, H+, Cl-, NO3-, SO42-, HSO4-, OH-, CO32-, HCO3-, and S2O82- are estimated. A computer...... program including a steady state process simulator for the design, simulation, and optimization of fractional crystallization processes is presented....

  2. Quantitative computer simulations of extraterrestrial processing operations

    Science.gov (United States)

    Vincent, T. L.; Nikravesh, P. E.

    1989-01-01

    The automation of a small, solid propellant mixer was studied. Temperature control is under investigation. A numerical simulation of the system is under development and will be tested using different control options. Control system hardware is currently being put into place. The construction of mathematical models and simulation techniques for understanding various engineering processes is also studied. Computer graphics packages were utilized for better visualization of the simulation results. The mechanical mixing of propellants is examined. Simulation of the mixing process is being done to study how one can control for chaotic behavior to meet specified mixing requirements. An experimental mixing chamber is also being built. It will allow visual tracking of particles under mixing. The experimental unit will be used to test ideas from chaos theory, as well as to verify simulation results. This project has applications to extraterrestrial propellant quality and reliability.

  3. Launch Site Computer Simulation and its Application to Processes

    Science.gov (United States)

    Sham, Michael D.

    1995-01-01

    This paper provides an overview of computer simulation, the Lockheed developed STS Processing Model, and the application of computer simulation to a wide range of processes. The STS Processing Model is an icon driven model that uses commercial off the shelf software and a Macintosh personal computer. While it usually takes one year to process and launch 8 space shuttles, with the STS Processing Model this process is computer simulated in about 5 minutes. Facilities, orbiters, or ground support equipment can be added or deleted and the impact on launch rate, facility utilization, or other factors measured as desired. This same computer simulation technology can be used to simulate manufacturing, engineering, commercial, or business processes. The technology does not require an 'army' of software engineers to develop and operate, but instead can be used by the layman with only a minimal amount of training. Instead of making changes to a process and realizing the results after the fact, with computer simulation, changes can be made and processes perfected before they are implemented.

  4. General simulation algorithm for autocorrelated binary processes

    Science.gov (United States)

    Serinaldi, Francesco; Lombardo, Federico

    2017-02-01

    The apparent ubiquity of binary random processes in physics and many other fields has attracted considerable attention from the modeling community. However, generation of binary sequences with prescribed autocorrelation is a challenging task owing to the discrete nature of the marginal distributions, which makes the application of classical spectral techniques problematic. We show that such methods can effectively be used if we focus on the parent continuous process of beta distributed transition probabilities rather than on the target binary process. This change of paradigm results in a simulation procedure effectively embedding a spectrum-based iterative amplitude-adjusted Fourier transform method devised for continuous processes. The proposed algorithm is fully general, requires minimal assumptions, and can easily simulate binary signals with power-law and exponentially decaying autocorrelation functions corresponding, for instance, to Hurst-Kolmogorov and Markov processes. An application to rainfall intermittency shows that the proposed algorithm can also simulate surrogate data preserving the empirical autocorrelation.

  5. Hydrodynamics of the Zero-Range Process in the Condensation Regime

    Science.gov (United States)

    Schütz, G. M.; Harris, R. J.

    2007-04-01

    We argue that the coarse-grained dynamics of the zero-range process in the condensation regime can be described by an extension of the standard hydrodynamic equation obtained from Eulerian scaling even though the system is not locally stationary. Our result is supported by Monte Carlo simulations.

  6. Simulating the Wire Compensation of LHC Long-Range Beam-beam Effects.

    CERN Document Server

    Rijoff, T

    2012-01-01

    The performance of the Large Hadron Collider (LHC) and its minimum crossing angle are limited by long-range beam-beam collisions. Wire compensators can mitigate part of the long-range effects. We perform simulations to explore the efficiency of the compensation at possible wire locations by examining the tune footprint and the dynamic aperture. Starting from the weak-strong simulation code BBTrack we developed a new Lyapunov calculation tool, which seems to better diagnose regular or chaotic particle behavior. We also developed faster ways to execute the simulation and the post-processing. These modifications have allowed us to study different wire positions (longitudinal and transverse), varying wire currents, several wire shapes, and a range of beam-beam crossing angles, in view of a prototype wire installation in the LHC foreseen for 2014/15. Our simulations demonstrate that the wire can provide a good compensation, including for reduced crossing angle. Among the benefits of an LHC wire compensator are a b...

  7. Towards Process-based Range Modeling of Many Species.

    Science.gov (United States)

    Evans, Margaret E K; Merow, Cory; Record, Sydne; McMahon, Sean M; Enquist, Brian J

    2016-11-01

    Understanding and forecasting species' geographic distributions in the face of global change is a central priority in biodiversity science. The existing view is that one must choose between correlative models for many species versus process-based models for few species. We suggest that opportunities exist to produce process-based range models for many species, by using hierarchical and inverse modeling to borrow strength across species, fill data gaps, fuse diverse data sets, and model across biological and spatial scales. We review the statistical ecology and population and range modeling literature, illustrating these modeling strategies in action. A variety of large, coordinated ecological datasets that can feed into these modeling solutions already exist, and we highlight organisms that seem ripe for the challenge. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Simulation of Glass Fiber Forming Processes

    DEFF Research Database (Denmark)

    Von der Ohe, Renate

    Two glass fiber forming processes have been simulated using FEM, which are the drawing of continuous glass fibers for reinforcement purposes and the spinning of discontinuous glass fibers - stone wool for insulation. The aim of this work was to set up a numerical model for each process, and to use...

  9. Simulation of the perpendicular magnetic recording process

    NARCIS (Netherlands)

    Beusekamp, M.F.

    This thesis describes a simulation modelof the complete perpendicular magnetic recording process, from write current to readback voltage. Gontradictory to most models published in literature, it is neither analytical nor iterative. In the model of this thesis, the actual physical process is

  10. CFD Simulations of the Supersonic Inflatable Aerodynamic Decelerator (SIAD) Ballistic Range Tests

    Science.gov (United States)

    Brock, Joseph; Stern, Eric; Wilder, Michael

    2017-01-01

    A series of ballistic range tests were performed on a scaled model of the Supersonic Flight Demonstration Test (SFDT) intended to test the Supersonic Inflatable Aerodynamic Decelerator (SIAD) geometry. The purpose of these experiments were to provide aerodynamic coefficients of the vehicle to aid in mission and vehicle design. The experimental data spans the moderate Mach number range, $3.8-2.0$, with a total angle of attack ($alpha_T$) range, $10o-20o$. These conditions are intended to span the Mach-$alpha$ space for the majority of the SFDT experiment. In an effort to validate the predictive capabilities of Computational Fluid Dynamics (CFD) for free-flight aerodynamic behavior, numerical simulations of the ballistic range experiment are performed using the unstructured finite volume Navier-Stokes solver, US3D. Comparisons to raw vehicle attitude, and post-processed aerodynamic coefficients are made between simulated results and experimental data. The resulting comparisons for both raw model attitude and derived aerodynamic coefficients show good agreement with experimental results. Additionally, near body pressure field values for each trajectory simulated are investigated. Extracted surface and wake pressure data gives further insights into dynamic flow coupling leading to a potential mechanism for dynamic instability.

  11. Defense Waste Processing Facility Process Simulation Package Life Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Reuter, K.

    1991-12-31

    The Defense Waste Processing Facility (DWPF) will be used to immobilize high level liquid radioactive waste into safe, stable, and manageable solid form. The complexity and classification of the facility requires that a performance based operator training to satisfy Department of Energy orders and guidelines. A major portion of the training program will be the application and utilization of Process Simulation Packages to assist in training the Control Room Operators on the fluctionality of the process and the application of the Distribution Control System (DCS) in operating and managing the DWPF process. The packages are being developed by the DWPF Computer and Information Systems Simulation Group. This paper will describe the DWPF Process Simulation Package Life Cycle. The areas of package scope, development, validation, and configuration management will be reviewed and discussed in detail.

  12. On the simulation and mitigation of anisoplanatic optical turbulence for long range imaging

    Science.gov (United States)

    Hardie, Russell C.; LeMaster, Daniel A.

    2017-05-01

    We describe a numerical wave propagation method for simulating long range imaging of an extended scene under anisoplanatic conditions. Our approach computes an array of point spread functions (PSFs) for a 2D grid on the object plane. The PSFs are then used in a spatially varying weighted sum operation, with an ideal image, to produce a simulated image with realistic optical turbulence degradation. To validate the simulation we compare simulated outputs with the theoretical anisoplanatic tilt correlation and differential tilt variance. This is in addition to comparing the long- and short-exposure PSFs, and isoplanatic angle. Our validation analysis shows an excellent match between the simulation statistics and the theoretical predictions. The simulation tool is also used here to quantitatively evaluate a recently proposed block- matching and Wiener filtering (BMWF) method for turbulence mitigation. In this method block-matching registration algorithm is used to provide geometric correction for each of the individual input frames. The registered frames are then averaged and processed with a Wiener filter for restoration. A novel aspect of the proposed BMWF method is that the PSF model used for restoration takes into account the level of geometric correction achieved during image registration. This way, the Wiener filter is able fully exploit the reduced blurring achieved by registration. The BMWF method is relatively simple computationally, and yet, has excellent performance in comparison to state-of-the-art benchmark methods.

  13. Dynamic simulator for anaerobic digestion processes.

    Science.gov (United States)

    Kleinstreuer, C; Poweigha, T

    1982-09-01

    A transient, two-culture model simulating methane production from biomass has been developed. The simulator, based partially on the work by Andrews and McCarty, is capable of calculating the hydrolysis products of several common organic materials, accommodating various substrate feeding modes, and simulating the transient physico-biochemical transport and conversion processes occurring in the biological, liquid, and gaseous phases of a well-mixed reactor. The mathematical representation of this bioconversion system consists of a set of 11 coupled, nonlinear first-order rate equations based on the principles of mass conservation and biochemical reaction kinetics. The model can be used in conjunction with laboratory investigations and as a simulator for evaluating process control strategies and cost developments.

  14. Hospital Registration Process Reengineering Using Simulation Method

    Directory of Open Access Journals (Sweden)

    Qiang Su

    2010-01-01

    Full Text Available With increasing competition, many healthcare organizations have undergone tremendous reform in the last decade aiming to increase efficiency, decrease waste, and reshape the way that care is delivered. This study focuses on the operational efficiency improvement of hospital’s registration process. The operational efficiency related factors including the service process, queue strategy, and queue parameters were explored systematically and illustrated with a case study. Guided by the principle of business process reengineering (BPR, a simulation approach was employed for process redesign and performance optimization. As a result, the queue strategy is changed from multiple queues and multiple servers to single queue and multiple servers with a prepare queue. Furthermore, through a series of simulation experiments, the length of the prepare queue and the corresponding registration process efficiency was quantitatively evaluated and optimized.

  15. Zero Range Process and Multi-Dimensional Random Walks

    Science.gov (United States)

    Bogoliubov, Nicolay M.; Malyshev, Cyril

    2017-07-01

    The special limit of the totally asymmetric zero range process of the low-dimensional non-equilibrium statistical mechanics described by the non-Hermitian Hamiltonian is considered. The calculation of the conditional probabilities of the model are based on the algebraic Bethe ansatz approach. We demonstrate that the conditional probabilities may be considered as the generating functions of the random multi-dimensional lattice walks bounded by a hyperplane. This type of walks we call the walks over the multi-dimensional simplicial lattices. The answers for the conditional probability and for the number of random walks in the multi-dimensional simplicial lattice are expressed through the symmetric functions.

  16. Animated-simulation modeling facilitates clinical-process costing.

    Science.gov (United States)

    Zelman, W N; Glick, N D; Blackmore, C C

    2001-09-01

    Traditionally, the finance department has assumed responsibility for assessing process costs in healthcare organizations. To enhance process-improvement efforts, however, many healthcare providers need to include clinical staff in process cost analysis. Although clinical staff often use electronic spreadsheets to model the cost of specific processes, PC-based animated-simulation tools offer two major advantages over spreadsheets: they allow clinicians to interact more easily with the costing model so that it more closely represents the process being modeled, and they represent cost output as a cost range rather than as a single cost estimate, thereby providing more useful information for decision making.

  17. Improvements in metallurgical processes by simulation

    Directory of Open Access Journals (Sweden)

    Kjell O. Solberg

    1990-01-01

    Full Text Available The metallurgical industry is very important to Norway. Traditionally cheap hydro-power has been the basis for this energy-intensive industry. This advantage is now gradually disappearing. To be competitive in the future, a superior technology has to be developed. For this purpose simulation has been taken into extensive use. Close cooperation is established between the industry and research institutes. This is vital for success. Simulation has proved to be an important tool in two areas: the optimum design of processes and the continuous supervision to keep them running at optimum. This paper gives examples of how substantial improvements have been obtained in the production of aluminium and ferro-alloys. Based on this experience the author draws some general conclusions on how to utilize simulation to increase industrial productivity. In the future a new area is envisaged; simulation in the development of advanced materials and products.

  18. Neurological Evidence Linguistic Processes Precede Perceptual Simulation in Conceptual Processing

    Directory of Open Access Journals (Sweden)

    Max eLouwerse

    2012-10-01

    Full Text Available There is increasing evidence from response time experiments that language statistics and perceptual simulations both play a role in conceptual processing. In an EEG experiment we compared neural activity in cortical regions commonly associated with linguistic processing and visual perceptual processing to determine to what extent symbolic and embodied accounts of cognition applied. Participants were asked to determine the semantic relationship of word pairs (e.g., sky – ground or to determine their iconic relationship (i.e., if the presentation of the pair matched their expected physical relationship. A linguistic bias was found towards the semantic judgment task and a perceptual bias was found towards the iconicity judgment task. More importantly, conceptual processing involved activation in brain regions associated with both linguistic and perceptual processes. When comparing the relative activation of linguistic cortical regions with perceptual cortical regions, the effect sizes for linguistic cortical regions were larger than those for the perceptual cortical regions early in a trial with the reverse being true later in a trial. These results map upon findings from other experimental literature and provide further evidence that processing of concept words relies both on language statistics and on perceptual simulations, whereby linguistic processes precede perceptual simulation processes.

  19. A simulation study on garment manufacturing process

    Science.gov (United States)

    Liong, Choong-Yeun; Rahim, Nur Azreen Abdul

    2015-02-01

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

  20. Holistic simulation of geotechnical installation processes benchmarks and simulations

    CERN Document Server

    2016-01-01

    This book examines in detail the entire process involved in implementing geotechnical projects, from a well-defined initial stress and deformation state, to the completion of the installation process.   The individual chapters provide the fundamental knowledge needed to effectively improve soil-structure interaction models. Further, they present the results of theoretical fundamental research on suitable constitutive models, contact formulations, and efficient numerical implementations and algorithms. Applications of fundamental research on boundary value problems are also considered in order to improve the implementation of the theoretical models developed. Subsequent chapters highlight parametric studies of the respective geotechnical installation process, as well as elementary and large-scale model tests under well-defined conditions, in order to identify the most essential parameters for optimizing the process. The book provides suitable methods for simulating boundary value problems in connection with g...

  1. Application of process simulators in chemical engineering process design -natural gas separation plant case study

    Directory of Open Access Journals (Sweden)

    Stevanović Dimitrije Ž.

    2014-01-01

    Full Text Available Software for chemical processes modeling and simulation, in the past few decades, play an important role in the development of chemical-process industry with their growing capabilities and wide range of application. Usage of process simulators in Serbia for the process design is very limited. This paper gives a brief overview of the numerous process simulators that are used in the chemical-process industry today. The conceptual design is responsible for most of the investment costs in chemical process industry. Importance of precise design on preliminary level is obvious. Wrong decisions made at the conceptual level could be carried out throughout the chain in process design to the detailed design procedures and procurement of equipment. Although preliminary design phase comprises only about 2% of the total cost of the project, it contributes significantly to the reduction of cost of the project by more than 30%. Therefore process simulators play important role in elimination of unnecessary errors in basic process design. Here is also shown a case study of parallel process simulated in different process simulators which tests the results, the reliability and usefulness of these programs in solving specific engineering tasks. Comparison of given simulation results confirm that the modern process simulators are at high level of confidence, no matter they are based on different models, equations, methods, operations, interfaces or data bases. Usage of software speeds up the arrival of optimized solution during the design and the operational procedures. Therefore software have significant impact on reducing time of pre-project phase such as research, conceptual design, and proving project abilities. It’s development lead to faster commercialization of industrial ideas. [Projekat Ministartsva nauke Republike Srbije, br. TR 34009

  2. Simulation and optimization of fractional crystallization processes

    DEFF Research Database (Denmark)

    Thomsen, Kaj; Rasmussen, Peter; Gani, Rafiqul

    1998-01-01

    A general method for the calculation of various types of phase diagrams for aqueous electrolyte mixtures is outlined. It is shown how the thermodynamic equilibrium precipitation process can be used to satisfy the operational needs of industrial crystallizer/centrifuge units. Examples of simulation...... and optimization of fractional crystallization processes are shown. In one of these examples, a process with multiple steady states is analyzed. The thermodynamic model applied for describing the highly non-ideal aqueous electrolyte systems is the Extended UNIQUAC model. (C) 1998 Published by Elsevier Science Ltd...

  3. Atomistic simulations of dislocation processes in copper

    DEFF Research Database (Denmark)

    Vegge, T.; Jacobsen, K.W.

    2002-01-01

    We discuss atomistic simulations of dislocation processes in copper based on effective medium theory interatomic potentials. Results on screw dislocation structures and processes are reviewed with particular focus on point defect mobilities and processes involving cross slip. For example, the sta...... of vacancy controlled climb show the jogs to climb easily in their extended form. The stability of small vacancy dipoles is discussed and it is seen that the introduction of jogs may lead to the formation of Z-type faulted vacancy dipoles....

  4. Modeling and simulation of economic processes

    Directory of Open Access Journals (Sweden)

    Bogdan Brumar

    2010-12-01

    Full Text Available In general, any activity requires a longer action often characterized by a degree of uncertainty, insecurity, in terms of size of the objective pursued. Because of the complexity of real economic systems, the stochastic dependencies between different variables and parameters considered, not all systems can be adequately represented by a model that can be solved by analytical methods and covering all issues for management decision analysis-economic horizon real. Often in such cases, it is considered that the simulation technique is the only alternative available. Using simulation techniques to study real-world systems often requires a laborious work. Making a simulation experiment is a process that takes place in several stages.

  5. Simulation of diesel engine energy conversion processes

    Directory of Open Access Journals (Sweden)

    А. С. Афанасьев

    2016-12-01

    Full Text Available In order to keep diesel engines in good working order the troubleshooting methods shall be improved. For their further improvement by parameters of associated processes a need has arisen to develop a diesel engine troubleshooting method based on time parameters of operating cycle. For such method to be developed a computational experiment involving simulation of diesel engine energy conversion processes has been carried out. The simulation was based on the basic mathematical model of reciprocating internal combustion engines, representing a closed system of equations and relationships. The said model has been supplemented with the engine torque dynamics taking into account the current values of in-cylinder processes with different amounts of fuel injected, including zero feed.The torque values obtained by the in-cylinder pressure conversion does not account for mechanical losses, which is why the base simulation program has been supplemented with calculations for the friction and pumping forces. In order to determine the indicator diagram of idle cylinder a transition to zero fuel feed mode and exclusion of the combustion process from calculation have been provisioned.

  6. Earthquake simulations with time-dependent nucleation and long-range interactions

    Directory of Open Access Journals (Sweden)

    J. H. Dieterich

    1995-01-01

    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.

  7. Calibrating and testing a gap model for simulating forest management in the Oregon Coast Range

    Science.gov (United States)

    Robert J. Pabst; Matthew N. Goslin; Steven L. Garman; Thomas A. Spies

    2008-01-01

    The complex mix of economic and ecological objectives facing today's forest managers necessitates the development of growth models with a capacity for simulating a wide range of forest conditions while producing outputs useful for economic analyses. We calibrated the gap model ZELIG to simulate stand level forest development in the Oregon Coast Range as part of a...

  8. Numerical simulations of regolith sampling processes

    Science.gov (United States)

    Schäfer, Christoph M.; Scherrer, Samuel; Buchwald, Robert; Maindl, Thomas I.; Speith, Roland; Kley, Wilhelm

    2017-07-01

    We present recent improvements in the simulation of regolith sampling processes in microgravity using the numerical particle method smooth particle hydrodynamics (SPH). We use an elastic-plastic soil constitutive model for large deformation and failure flows for dynamical behaviour of regolith. In the context of projected small body (asteroid or small moons) sample return missions, we investigate the efficiency and feasibility of a particular material sampling method: Brushes sweep material from the asteroid's surface into a collecting tray. We analyze the influence of different material parameters of regolith such as cohesion and angle of internal friction on the sampling rate. Furthermore, we study the sampling process in two environments by varying the surface gravity (Earth's and Phobos') and we apply different rotation rates for the brushes. We find good agreement of our sampling simulations on Earth with experiments and provide estimations for the influence of the material properties on the collecting rate.

  9. Learning process optimization by mathematical simulation means.

    Directory of Open Access Journals (Sweden)

    I. Vereitina

    2009-06-01

    Full Text Available The results of the study are directed to the methodic of learning process analyzes verifying and complex measures for its improving, i.e. optimal criterion definition – knowledge volume and influencing optimization parameters – activity aspects under conditions of high – grade training providing. According to the learning process optimization task mathematical simulation results on the example of foreign language it was shown that between the knowledge volume and training aspects the considerable non-linear connection exists which should be taken into consideration when making the syllabus and skills evaluation.

  10. Computer Simulation of Electron Positron Annihilation Processes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, y

    2003-10-02

    With the launching of the Next Linear Collider coming closer and closer, there is a pressing need for physicists to develop a fully-integrated computer simulation of e{sup +}e{sup -} annihilation process at center-of-mass energy of 1TeV. A simulation program acts as the template for future experiments. Either new physics will be discovered, or current theoretical uncertainties will shrink due to more accurate higher-order radiative correction calculations. The existence of an efficient and accurate simulation will help us understand the new data and validate (or veto) some of the theoretical models developed to explain new physics. It should handle well interfaces between different sectors of physics, e.g., interactions happening at parton levels well above the QCD scale which are described by perturbative QCD, and interactions happening at much lower energy scale, which combine partons into hadrons. Also it should achieve competitive speed in real time when the complexity of the simulation increases. This thesis contributes some tools that will be useful for the development of such simulation programs. We begin our study by the development of a new Monte Carlo algorithm intended to perform efficiently in selecting weight-1 events when multiple parameter dimensions are strongly correlated. The algorithm first seeks to model the peaks of the distribution by features, adapting these features to the function using the EM algorithm. The representation of the distribution provided by these features is then improved using the VEGAS algorithm for the Monte Carlo integration. The two strategies mesh neatly into an effective multi-channel adaptive representation. We then present a new algorithm for the simulation of parton shower processes in high energy QCD. We want to find an algorithm which is free of negative weights, produces its output as a set of exclusive events, and whose total rate exactly matches the full Feynman amplitude calculation. Our strategy is to create

  11. Process Simulation Analysis of HF Stripping

    Directory of Open Access Journals (Sweden)

    Thaer A. Abdulla

    2013-05-01

    Full Text Available    HYSYS process simulator is used for the analysis of existing HF stripping column in LAB plant (Arab Detergent Company, Baiji-Iraq. Simulated column performance and profiles curves are constructed. The variables considered are the thermodynamic model option, bottom temperature, feed temperature, and column profiles for the temperature, vapor flow rate, liquid flow rate and composition. The five thermodynamic models options used (Margules, UNIQUAC, van laar, Antoine, and Zudkevitch-Joffee, affecting the results within (0.1-58% variation for the most cases.        The simulated results show that about 4% of paraffin (C10 & C11 presents at the top stream, which may cause a problem in the LAB production plant. The major variations were noticed for the total top vapor flow rate with bottom temperature and with feed composition. The column profiles maintain fairly constants from tray 5 to tray 18. The study gives evidence about a successful simulation with HYSYS because the results correspond with the real plant operation data.

  12. Optimal Hamiltonian Simulation by Quantum Signal Processing.

    Science.gov (United States)

    Low, Guang Hao; Chuang, Isaac L

    2017-01-06

    The physics of quantum mechanics is the inspiration for, and underlies, quantum computation. As such, one expects physical intuition to be highly influential in the understanding and design of many quantum algorithms, particularly simulation of physical systems. Surprisingly, this has been challenging, with current Hamiltonian simulation algorithms remaining abstract and often the result of sophisticated but unintuitive constructions. We contend that physical intuition can lead to optimal simulation methods by showing that a focus on simple single-qubit rotations elegantly furnishes an optimal algorithm for Hamiltonian simulation, a universal problem that encapsulates all the power of quantum computation. Specifically, we show that the query complexity of implementing time evolution by a d-sparse Hamiltonian H[over ^] for time-interval t with error ε is O[td∥H[over ^]∥_{max}+log(1/ε)/loglog(1/ε)], which matches lower bounds in all parameters. This connection is made through general three-step "quantum signal processing" methodology, comprised of (i) transducing eigenvalues of H[over ^] into a single ancilla qubit, (ii) transforming these eigenvalues through an optimal-length sequence of single-qubit rotations, and (iii) projecting this ancilla with near unity success probability.

  13. Simulation of recording the microwave holograms of complex objects by the near range radars

    Directory of Open Access Journals (Sweden)

    V. V. Razevig

    2014-01-01

    Full Text Available Radar is an object-detection technology that uses radio waves to determine the presence, range, altitude, direction, or speed of objects. In the recent time, there is an increasingly arising interest to the near range microwave imaging that allows detection of the shape and, in some cases, the inner structure of the investigated objects.For design engineering and efficiency evaluation of the cutting-edge radars as well as for testing the developed recovery algorithms a set of microwave holograms of various objects obtained under different conditions is needed. Microwave holograms cannot be obtained only on the basis of the experimental researches related to the measurements of electromagnetic scattering by the real objects since such experiments are time consuming and quite expensive. Therefore, to simulate electromagnetic scattering processes via objects examination is quite a challenge.This investigation goal is to develop a computer simulation method to record the microwave holograms of complex objects by the near range radars.To specify the shape of the investigated objects, Autodesk 3ds Max (3D computer graphics program for making 3D animations, models, and images is used. At a second stage the surface of the created object is described by a set of triangular facets. While calculating the reflected field, a final representation of the object as a set of point reflectors is used. Thus, the model of single scattering, is used without taking into consideration re-reflection and cross-influence of reflectors.Methods are also described to form the focused images of the microwave holograms that allow us to obtain a function describing object reflectivity, by which in most cases an object shape can be easily recognized.A comparison of computer-simulated holograms with experimental data proves the model adequacy.The model can be used to find a dependence of the plane resolution on used frequency, step of scanning, and distance to the object and a

  14. Coupling Computer-Aided Process Simulation and ...

    Science.gov (United States)

    A methodology is described for developing a gate-to-gate life cycle inventory (LCI) of a chemical manufacturing process to support the application of life cycle assessment in the design and regulation of sustainable chemicals. The inventories were derived by first applying process design and simulation of develop a process flow diagram describing the energy and basic material flows of the system. Additional techniques developed by the U.S. Environmental Protection Agency for estimating uncontrolled emissions from chemical processing equipment were then applied to obtain a detailed emission profile for the process. Finally, land use for the process was estimated using a simple sizing model. The methodology was applied to a case study of acetic acid production based on the Cativa tm process. The results reveal improvements in the qualitative LCI for acetic acid production compared to commonly used databases and top-down methodologies. The modeling techniques improve the quantitative LCI results for inputs and uncontrolled emissions. With provisions for applying appropriate emission controls, the proposed method can provide an estimate of the LCI that can be used for subsequent life cycle assessments. As part of its mission, the Agency is tasked with overseeing the use of chemicals in commerce. This can include consideration of a chemical's potential impact on health and safety, resource conservation, clean air and climate change, clean water, and sustainable

  15. Invariance principle, multifractional Gaussian processes and long-range dependence

    OpenAIRE

    Cohen, Serge; Marty, Renaud

    2008-01-01

    This paper is devoted to establish an invariance principle where the limit process is a multifractional Gaussian process with a multifractional function which takes its values in $(1/2,1)$. Some properties, such as regularity and local self-similarity of this process are studied. Moreover the limit process is compared to the multifractional Brownian motion.

  16. Process efficiency simulation for key process parameters in biological methanogenesis

    Directory of Open Access Journals (Sweden)

    Sébastien Bernacchi

    2014-09-01

    Full Text Available New generation biofuels are a suitable approach to produce energy carriers in an almost CO2 neutral way. A promising reaction is the conversion of CO2 and H2 to CH4. This contribution aims at elucidating a bioprocess comprised of a core reaction unit using microorganisms from the Archaea life domain, which metabolize CO2 and H2 to CH4, followed by a gas purification step. The process is simulated and analyzed thermodynamically using the Aspen Plus process simulation environment. The goal of the study was to quantify effects of process parameters on overall process efficiency using a kinetic model derived from previously published experimental results. The used empirical model links the production rate of CH4 and biomass to limiting reactant concentrations. In addition, Aspen Plus was used to improve bioprocess quantification. Impacts of pressure as well as dilution of reactant gas with up to 70% non-reactive gas on overall process efficiency was evaluated. Pressure in the reactor unit of 11 bar at 65℃ with a pressure of 21 bar for gas purification led to an overall process efficiency comprised between 66% and 70% for gaseous product and between 73% and 76% if heat of compression is considered a valuable product. The combination of 2 bar pressure in the reactor and 21 bar for purification was the most efficient combination of parameters. This result shows Aspen Plus potential for similar bioprocess development as it accounts for the energetic aspect of the entire process. In fact, the optimum for the overall process efficiency was found to differ from the optimum of the reaction unit. High efficiency of over 70% demonstrates that biological methanogenesis is a promising alternative for a chemical methanation reaction.

  17. Simulating non-Markovian stochastic processes.

    Science.gov (United States)

    Boguñá, Marian; Lafuerza, Luis F; Toral, Raúl; Serrano, M Ángeles

    2014-10-01

    We present a simple and general framework to simulate statistically correct realizations of a system of non-Markovian discrete stochastic processes. We give the exact analytical solution and a practical and efficient algorithm like the Gillespie algorithm for Markovian processes, with the difference being that now the occurrence rates of the events depend on the time elapsed since the event last took place. We use our non-Markovian generalized Gillespie stochastic simulation methodology to investigate the effects of nonexponential interevent time distributions in the susceptible-infected-susceptible model of epidemic spreading. Strikingly, our results unveil the drastic effects that very subtle differences in the modeling of non-Markovian processes have on the global behavior of complex systems, with important implications for their understanding and prediction. We also assess our generalized Gillespie algorithm on a system of biochemical reactions with time delays. As compared to other existing methods, we find that the generalized Gillespie algorithm is the most general because it can be implemented very easily in cases (such as for delays coupled to the evolution of the system) in which other algorithms do not work or need adapted versions that are less efficient in computational terms.

  18. Numerical Simulation of Cyclic Thermodynamic Processes

    DEFF Research Database (Denmark)

    Andersen, Stig Kildegård

    2006-01-01

    This thesis is on numerical simulation of cyclic thermodynamic processes. A modelling approach and a method for finding periodic steady state solutions are described. Examples of applications are given in the form of four research papers. Stirling machines and pulse tube coolers are introduced......, compressible flow in one space dimension is presented. The implementation produces models where all the equations, which are on a form that should be understandable to someone with a background in engineering thermodynamics, can be accessed and modified individually. The implementation was designed to make...

  19. Simulation of the styrene production process via catalytic dehydrogenation of ethylbenzene using CHEMCAD® process simulator

    Directory of Open Access Journals (Sweden)

    Amaury Pérez Sánchez

    2017-07-01

    Full Text Available Background: Process simulation has been extensively used in recent years to design, evaluate or optimize processes, systems and specific operations of the chemical industry and its related disciplines. Currently, CHEMCAD® constitute one of the most used process simulators because of the great number of chemical and petrochemical processes that can be simulated. Method: The simulation of the production process of styrene via catalytic dehydrogenation of ethyl-benzene is carried out by using the process simulator CHEMCAD® version 5.2.0, in order to determine the composition and mass flow-rate of each process involved in the production, as well as the main operating parameters of the equipment used. Two sensitivity studies were carried out: firstly, the influence of the temperature and pressure values applied at the LLV Separator on the amounts of ethyl-benzene and styrene to be obtained by the intermediate and top currents of this equipment; secondly, the influence of the operating pressure of the Distillation Column No. 1 (benzene-toluene column on the quantity of ethyl-benzene and styrene obtained at the bottom stream. The simulating software MATLAB® version 7.8.0 was used to process the results obtained. Results: Around 9234.436 kg/h of styrene is obtained in the last distillation column with 99.6% purity. Additionally, it was found that the water is the main impurity found on this stream, which represents 0.35% of the weight. Conclusions: The LLV Separator must operate at a low temperature (5 – 10 ºC and at a relatively high pressure (10 bar, whereas the Distillation Column No. 1 must work at a pressure near atmospheric (1.0 bar, or preferably under vacuum conditions in order to obtain the highest yields of styrene and ethyl-benzene.

  20. Wide Output Range Power Processing Unit for Electric Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Hall thrusters can be operated over a wide range of specific impulse while maintaining high efficiency. However S/C power system constraints on electric propulsion...

  1. Wide Output Range Power Processing Unit for Electric Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A power supply concept capable of operation over 25:1 and 64:1 impedance ranges at full power has been successfully demonstrated in our Phase I effort at...

  2. Simulating the Composite Propellant Manufacturing Process

    Science.gov (United States)

    Williamson, Suzanne; Love, Gregory

    2000-01-01

    There is a strategic interest in understanding how the propellant manufacturing process contributes to military capabilities outside the United States. The paper will discuss how system dynamics (SD) has been applied to rapidly assess the capabilities and vulnerabilities of a specific composite propellant production complex. These facilities produce a commonly used solid propellant with military applications. The authors will explain how an SD model can be configured to match a specific production facility followed by a series of scenarios designed to analyze operational vulnerabilities. By using the simulation model to rapidly analyze operational risks, the analyst gains a better understanding of production complexities. There are several benefits of developing SD models to simulate chemical production. SD is an effective tool for characterizing complex problems, especially the production process where the cascading effect of outages quickly taxes common understanding. By programming expert knowledge into an SD application, these tools are transformed into a knowledge management resource that facilitates rapid learning without requiring years of experience in production operations. It also permits the analyst to rapidly respond to crisis situations and other time-sensitive missions. Most importantly, the quantitative understanding gained from applying the SD model lends itself to strategic analysis and planning.

  3. Simulation and Flexibility Analysis of Milk Production Process

    DEFF Research Database (Denmark)

    Cheng, Hongyuan; Friis, Alan

    In this work, process simulation method is used to simulate pasteurised market milk production line. A commercial process simulation tool - Pro/II from Simulation Science Inc. is used in the simulation work. In the simulation, a new model is used to calculate the thermal property of milk....... In this work, a simulator is obtained for the milk production line. Using the simulator, different milk processing situation can be quantitatively simulated investigated, such as different products production, capacity changes, fat content changes in raw milk, energy cost at different operation conditions etc....... As the pasteurised market milk production line involves typical milk processing steps, such as pasteurisation, centrifugal separation, standardisation, the simulator can be modified to simulate similar milk processing lines. In many cases, the rapidly changed market requires a flexible milk production line...

  4. Simulation-enhanced lean design process

    Directory of Open Access Journals (Sweden)

    Jon H. Marvel

    2009-07-01

    Full Text Available 72 Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} A traditional lean transformation process does not validate the future state before implementation, relying instead on a series of iterations to modify the system until performance is satisfactory. An enhanced lean process that includes future state validation before implementation is presented.  Simulation modeling and experimentation is proposed as the primary validation tool.  Simulation modeling and experimentation extends value stream mapping to include time, the behavior of individual entities, structural variability, random variability, and component interaction effects. Experiments to analyze the model and draw conclusions about whether the lean transformation effectively addresses the current state gap can be conducted.  Industrial applications of the enhanced lean process show it effectiveness.

  5. Virtual Collaborative Simulation Environment for Integrated Product and Process Development

    Science.gov (United States)

    Gulli, Michael A.

    1997-01-01

    Deneb Robotics is a leader in the development of commercially available, leading edge three- dimensional simulation software tools for virtual prototyping,, simulation-based design, manufacturing process simulation, and factory floor simulation and training applications. Deneb has developed and commercially released a preliminary Virtual Collaborative Engineering (VCE) capability for Integrated Product and Process Development (IPPD). This capability allows distributed, real-time visualization and evaluation of design concepts, manufacturing processes, and total factory and enterprises in one seamless simulation environment.

  6. The Range of Microbial Risks in Food Processing

    NARCIS (Netherlands)

    Zwietering, M.H.; Straver, J.M.; Asselt, van E.D.

    2016-01-01

    Foodborne illnesses can be caused by a wide range of microorganisms. Data analysis can help to determine which microorganisms give the highest contribution to the number of foodborne illnesses. This helps to decide which pathogen(s) to focus on in order to reduce the number of illnesses. The same

  7. Northwest range-plant symbols adapted to automatic data processing.

    Science.gov (United States)

    George A. Garrison; Jon M. Skovlin

    1960-01-01

    Many range technicians, agronomists, foresters, biologists, and botanists of various educational institutions and government agencies in the Northwest have been using a four-letter symbol list or code compiled 12 years ago from records of plants collected by the U.S. Forest Service in Oregon and Washington, This code has served well as a means of entering plant names...

  8. Simulated interprofessional education: an analysis of teaching and learning processes.

    Science.gov (United States)

    van Soeren, Mary; Devlin-Cop, Sandra; Macmillan, Kathleen; Baker, Lindsay; Egan-Lee, Eileen; Reeves, Scott

    2011-11-01

    Simulated learning activities are increasingly being used in health professions and interprofessional education (IPE). Specifically, IPE programs are frequently adopting role-play simulations as a key learning approach. Despite this widespread adoption, there is little empirical evidence exploring the teaching and learning processes embedded within this type of simulation. This exploratory study provides insight into the nature of these processes through the use of qualitative methods. A total of 152 clinicians, 101 students and 9 facilitators representing a range of health professions, participated in video-recorded role-plays and debrief sessions. Videotapes were analyzed to explore emerging issues and themes related to teaching and learning processes related to this type of interprofessional simulated learning experience. In addition, three focus groups were conducted with a subset of participants to explore perceptions of their educational experiences. Five key themes emerged from the data analysis: enthusiasm and motivation, professional role assignment, scenario realism, facilitator style and background and team facilitation. Our findings suggest that program developers need to be mindful of these five themes when using role-plays in an interprofessional context and point to the importance of deliberate and skilled facilitation in meeting desired learning outcomes.

  9. Realistic simulation of laser range finder behavior in a smoky environment

    NARCIS (Netherlands)

    Formsma, O.; Dijkshoorn, N.; van Noort, S.; Visser, A.; Ruiz-del-Solar, J.; Chown, E.; Plöger, P.G.

    2011-01-01

    The Urban Search and Rescue Simulation used for RoboCup lacks realistic response of laser range finders on smoke. In this paper, the behavior of a Hokuyo and Sick laser range finder in a smoky environment is studied. The behavior of the lasers is among others a function of the visibility level, and

  10. Evaluating the effects of cutoffs and treatment of long-range electrostatics in protein folding simulations.

    Directory of Open Access Journals (Sweden)

    Stefano Piana

    Full Text Available The use of molecular dynamics simulations to provide atomic-level descriptions of biological processes tends to be computationally demanding, and a number of approximations are thus commonly employed to improve computational efficiency. In the past, the effect of these approximations on macromolecular structure and stability has been evaluated mostly through quantitative studies of small-molecule systems or qualitative observations of short-timescale simulations of biological macromolecules. Here we present a quantitative evaluation of two commonly employed approximations, using a test system that has been the subject of a number of previous protein folding studies--the villin headpiece. In particular, we examined the effect of (i the use of a cutoff-based force-shifting technique rather than an Ewald summation for the treatment of electrostatic interactions, and (ii the length of the cutoff used to determine how many pairwise interactions are included in the calculation of both electrostatic and van der Waals forces. Our results show that the free energy of folding is relatively insensitive to the choice of cutoff beyond 9 Å, and to whether an Ewald method is used to account for long-range electrostatic interactions. In contrast, we find that the structural properties of the unfolded state depend more strongly on the two approximations examined here.

  11. Agglomeration processes in carbonaceous dusty plasmas, experiments and numerical simulations

    Energy Technology Data Exchange (ETDEWEB)

    Dap, S; Hugon, R; De Poucques, L; Bougdira, J [Nancy Universite-Institut Jean Lamour, Dpt CP2S UMR 7198 CNRS, Faculte des Sciences et Technologies, BP 70239, 54506 Vandoeuvre-les-Nancy cedex (France); Lacroix, D [Nancy Universite-LEMTA, UMR 7563 CNRS, Faculte des Sciences et Technologies, BP 70239, 54506 Vandoeuvre-les-Nancy cedex (France); Patisson, F, E-mail: david.lacroix@lemta.uhp-nancy.f [Nancy Universite-Institut Jean Lamour, Dpt SI2M UMR 7198 CNRS, Ecole des Mines de Nancy, Parc de Saurupt-CS 14234, 54042 Nancy cedex (France)

    2010-09-15

    This paper deals with carbon dust agglomeration in radio frequency acetylene/argon plasma. Two studies, an experimental and a numerical one, were carried out to model dust formation mechanisms. Firstly, in situ transmission spectroscopy of dust clouds in the visible range was performed in order to observe the main features of the agglomeration process of the produced carbonaceous dust. Secondly, numerical simulation tools dedicated to understanding the achieved experiments were developed. A first model was used for the discretization of the continuous population balance equations that characterize the dust agglomeration process. The second model is based on a Monte Carlo ray-tracing code coupled to a Mie theory calculation of dust absorption and scattering parameters. These two simulation tools were used together in order to numerically predict the light transmissivity through a dusty plasma and make comparisons with experiments.

  12. Improving the effectiveness of detailed processing by dynamic control of processing with high sports range

    Directory of Open Access Journals (Sweden)

    Yu.V. Shapoval

    2017-12-01

    Full Text Available In this article the possibility of increasing the efficiency of the processing of parts with a diameter of up to 20 mm is analyzed, namely: vibration resistance of the cutting process at pinching due to cutting speed control in the processing, forecasting and selection of rotational frequencies, which ensure the stability of the processing system, controlling the dynamics of the process of displacement of the additional mass. The method of investigation of vibration processes during the sharpening is developed. As a result of the processing of experimental data, it was found that when an oscillatory motion is applied to the spindle rotation, the overall level of oscillation decreases, which is reflected on the quality of the treated surface. The choice of a previously known spindle rotation frequency range at which the lowest value of the oscillation amplitude of the instrument is observed in the radial direction to the detail part, allows you to increase the processing efficiency while maintaining the drawing requirements for roughness by increasing the spindle rotational speed. The combination of the node of the own forms of oscillation and the cutting zone, by dynamically controlling the fluctuations of the lathe armature due to the increase of the inertia characteristics of the machine and the reduction of the oscillation amplitude of the tool, can improve the accuracy of machining and roughness of the processed surface of the component at higher spindle speeds.

  13. Business Process Simulation: Requirements for Business and Resource Models

    Directory of Open Access Journals (Sweden)

    Audrius Rima

    2015-07-01

    Full Text Available The purpose of Business Process Model and Notation (BPMN is to provide easily understandable graphical representation of business process. Thus BPMN is widely used and applied in various areas one of them being a business process simulation. This paper addresses some BPMN model based business process simulation problems. The paper formulate requirements for business process and resource models in enabling their use for business process simulation.

  14. Automation of data processing | G | African Journal of Range and ...

    African Journals Online (AJOL)

    Data processing can be time-consuming when experiments with advanced designs are employed. This, coupled with a shortage of research workers, necessitates automation. It is suggested that with automation the first step is to determine how the data must be analysed. The second step is to determine what programmes ...

  15. Ring rolling process simulation for geometry optimization

    Science.gov (United States)

    Franchi, Rodolfo; Del Prete, Antonio; Donatiello, Iolanda; Calabrese, Maurizio

    2017-10-01

    Ring Rolling is a complex hot forming process where different rolls are involved in the production of seamless rings. Since each roll must be independently controlled, different speed laws must be set; usually, in the industrial environment, a milling curve is introduced to monitor the shape of the workpiece during the deformation in order to ensure the correct ring production. In the present paper a ring rolling process has been studied and optimized in order to obtain anular components to be used in aerospace applications. In particular, the influence of process input parameters (feed rate of the mandrel and angular speed of main roll) on geometrical features of the final ring has been evaluated. For this purpose, a three-dimensional finite element model for HRR (Hot Ring Rolling) has been implemented in SFTC DEFORM V11. The FEM model has been used to formulate a proper optimization problem. The optimization procedure has been implemented in the commercial software DS ISight in order to find the combination of process parameters which allows to minimize the percentage error of each obtained dimension with respect to its nominal value. The software allows to find the relationship between input and output parameters applying Response Surface Methodology (RSM), by using the exact values of output parameters in the control points of the design space explored through FEM simulation. Once this relationship is known, the values of the output parameters can be calculated for each combination of the input parameters. After the calculation of the response surfaces for the selected output parameters, an optimization procedure based on Genetic Algorithms has been applied. At the end, the error between each obtained dimension and its nominal value has been minimized. The constraints imposed were the maximum values of standard deviations of the dimensions obtained for the final ring.

  16. Problem of long-range forces in the computer simulation of condensed media

    Energy Technology Data Exchange (ETDEWEB)

    Ceperely, D. (ed.)

    1980-07-01

    Simulation (both Monte Carlo and molecular dynamical) has become a powerful tool in the study of classical systems of particles interacting with short-range pair potentials. For systems involving long-range forces (e.g., Coulombic, dipolar, hydrodynamic) it is a different story. Relating infinite-system properties to the results of computer simulation involving relatively small numbers of particles, periodically replicated, raises difficult and challenging problems. The purpose of the workshop was to bring together a group of scientists, all of whom share a strong direct interest in clearly formulating and resolving these problems. There were 46 participants, most of whom have been actively engaged in simulations of Hamiltonian models of condensed media. A few participants were scientists who are not primarily concerned, themselves, with simulation, but who are deeply involved in the theory of such models.

  17. Ring rolling process simulation for microstructure optimization

    Science.gov (United States)

    Franchi, Rodolfo; Del Prete, Antonio; Donatiello, Iolanda; Calabrese, Maurizio

    2017-10-01

    Metal undergoes complicated microstructural evolution during Hot Ring Rolling (HRR), which determines the quality, mechanical properties and life of the ring formed. One of the principal microstructure properties which mostly influences the structural performances of forged components, is the value of the average grain size. In the present paper a ring rolling process has been studied and optimized in order to obtain anular components to be used in aerospace applications. In particular, the influence of process input parameters (feed rate of the mandrel and angular velocity of driver roll) on microstructural and on geometrical features of the final ring has been evaluated. For this purpose, a three-dimensional finite element model for HRR has been developed in SFTC DEFORM V11, taking into account also microstructural development of the material used (the nickel superalloy Waspalloy). The Finite Element (FE) model has been used to formulate a proper optimization problem. The optimization procedure has been developed in order to find the combination of process parameters which allows to minimize the average grain size. The Response Surface Methodology (RSM) has been used to find the relationship between input and output parameters, by using the exact values of output parameters in the control points of a design space explored through FEM simulation. Once this relationship is known, the values of the output parameters can be calculated for each combination of the input parameters. Then, an optimization procedure based on Genetic Algorithms has been applied. At the end, the minimum value of average grain size with respect to the input parameters has been found.

  18. Computer Simulation of a Hardwood Processing Plant

    Science.gov (United States)

    D. Earl Kline; Philip A. Araman

    1990-01-01

    The overall purpose of this paper is to introduce computer simulation as a decision support tool that can be used to provide managers with timely information. A simulation/animation modeling procedure is demonstrated for wood products manufacuring systems. Simulation modeling techniques are used to assist in identifying and solving problems. Animation is used for...

  19. Efficient processing of 3-sided range queries with probabilistic guarantees

    DEFF Research Database (Denmark)

    Kaporis, Alexis; Papadopoulos, Apostolos; Sioutas, Spyros

    2010-01-01

    over the O(log n) update time bound achieved by the classic Priority Search Tree of McCreight [23], as well as over the Fusion Priority Search Tree of Willard [30], which requires O(log n/log log n) time for all operations. Moreover, we externalize this solution, gaining O(logB n + t/B) worst case...... and O(logBlogn) amortized expected with high probability I/Os for query and update operations respectively, where B is the disk block size. Then, combining the Modified Priority Search Tree [27] with the Priority Search Tree [23], we achieve a query time of O(log log n + t) expected with high......This work studies the problem of 2-dimensional searching for the 3-sided range query of the form [a, b] x (-∞, c] in both main and external memory, by considering a variety of input distributions. A dynamic linear main memory solution is proposed, which answers 3-sided queries in O(log n + t) worst...

  20. Modelling and simulation of diffusive processes methods and applications

    CERN Document Server

    Basu, SK

    2014-01-01

    This book addresses the key issues in the modeling and simulation of diffusive processes from a wide spectrum of different applications across a broad range of disciplines. Features: discusses diffusion and molecular transport in living cells and suspended sediment in open channels; examines the modeling of peristaltic transport of nanofluids, and isotachophoretic separation of ionic samples in microfluidics; reviews thermal characterization of non-homogeneous media and scale-dependent porous dispersion resulting from velocity fluctuations; describes the modeling of nitrogen fate and transport

  1. Computer Simulation of Developmental Processes and ...

    Science.gov (United States)

    Rationale: Recent progress in systems toxicology and synthetic biology have paved the way to new thinking about in vitro/in silico modeling of developmental processes and toxicities, both for embryological and reproductive impacts. Novel in vitro platforms such as 3D organotypic culture models, engineered microscale tissues and complex microphysiological systems (MPS), together with computational models and computer simulation of tissue dynamics, lend themselves to a integrated testing strategies for predictive toxicology. As these emergent methodologies continue to evolve, they must be integrally tied to maternal/fetal physiology and toxicity of the developing individual across early lifestage transitions, from fertilization to birth, through puberty and beyond. Scope: This symposium will focus on how the novel technology platforms can help now and in the future, with in vitro/in silico modeling of complex biological systems for developmental and reproductive toxicity issues, and translating systems models into integrative testing strategies. The symposium is based on three main organizing principles: (1) that novel in vitro platforms with human cells configured in nascent tissue architectures with a native microphysiological environments yield mechanistic understanding of developmental and reproductive impacts of drug/chemical exposures; (2) that novel in silico platforms with high-throughput screening (HTS) data, biologically-inspired computational models of

  2. SIMULATION AS A TOOL FOR PROCESS OPTIMIZATION OF LOGISTIC SYSTEMS

    Directory of Open Access Journals (Sweden)

    Radko Popovič

    2015-09-01

    Full Text Available The paper deals with the simulation of the production processes, especially module of Siemens Tecnomatix software. Tecnomatix Process Simulate is designed for building new or modifying existing production processes. The simulation created in this software has a posibility for fast testing of planned changes or improvements of the production processes. On the base of simulation you can imagine the future picture of the real production system. 3D Simulation can reflects the actual status and conditions on the running system and of course, after some improvements, it can show the possible figure of the production system.

  3. IMPROVING MANUFACTURING PROCESSES USING SIMULATION METHODS

    Directory of Open Access Journals (Sweden)

    Sławomir KŁOS

    2016-12-01

    Full Text Available The paper presents the results of simulation research on buffer space allocated in a flow line and operation times influence on the throughput of a manufacturing system. The production line in the study consists of four stages and is based on a real machining manufacturing system of a small production enterprise. Using Tecnomatix Plant Simulation software, a simulation model of the system was created and set of experiments was planned. Simulation experiments were prepared for different capacities of intermediate buffers located between manufacturing resources and operation times as input parameters, and the throughput per hour and average life span of products as the output.

  4. Plasmonic Antennas Nanocoupler for Telecom Range: Simulation, Fabrication and Near-Field Characterization

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Malureanu, Radu; Lavrinenko, Andrei

    2014-01-01

    We report simulation, fabrication and, for the first time, full amplitude-phase near-field optical characterization in telecom range of the compact and efficient plasmonic nanoantenna based couplers. Near-field data allowed characterizing the subwavelength slot waveguide’s propagation losses...

  5. Simulation, Fabrication and Near-Field Characterization of Nanoantenna Couplers for Telecom Range

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Zenin, Vladimir A.; Malureanu, Radu

    2014-01-01

    We report a modified bow - tie antenna for light coupling to subwavelength plasmonic slot waveguide . Its effective area is 15 times larger than that of the bare waveguide terminatio n at the wavelength 1.55 μm . We demonstrate numerical simulation, fabrication and , for the first time, full ampl...... amplitude - phase near - field optical characterization of nanocoupler in telecom range ....

  6. The Contribution of Matched Envelope Dynamic Range to the Binaural Benefits in Simulated Bilateral Electric Hearing

    Science.gov (United States)

    Chen, Fei; Wong, Lena L. N.; Qiu, Jianxin; Liu, Yehai; Azimi, Behnam; Hu, Yi

    2013-01-01

    Purpose: This study examined the effects of envelope dynamic-range mismatch on the intelligibility of Mandarin speech in noise by simulated bilateral electric hearing. Method: Noise-vocoded Mandarin speech, corrupted by speech-shaped noise at 5 and 0 dB signal-to-noise ratios, was presented unilaterally or bilaterally to 10 normal-hearing…

  7. Process to create simulated lunar agglutinate particles

    Science.gov (United States)

    Gustafson, Robert J. (Inventor); Gustafson, Marty A. (Inventor); White, Brant C. (Inventor)

    2011-01-01

    A method of creating simulated agglutinate particles by applying a heat source sufficient to partially melt a raw material is provided. The raw material is preferably any lunar soil simulant, crushed mineral, mixture of crushed minerals, or similar material, and the heat source creates localized heating of the raw material.

  8. Discrete simulation of behavioural hybrid process calculus

    NARCIS (Netherlands)

    Krilavicius, T.; Schonenberg, Helen; Romijn, J.M.T.; Smith, G.P.; van de Pol, J.C.

    2005-01-01

    Hybrid systems combine continuous-time and discrete behaviours. Simulation is one of the tools to obtain insight in dynamical systems behaviour. Simulation results provide information on performance of system and are helpful in detecting potential weaknesses and errors. Moreover, the results are

  9. A numerical investigation on the efficiency of range extending systems using Advanced Vehicle Simulator

    Science.gov (United States)

    Varnhagen, Scott; Same, Adam; Remillard, Jesse; Park, Jae Wan

    2011-03-01

    Series plug-in hybrid electric vehicles of varying engine configuration and battery capacity are modeled using Advanced Vehicle Simulator (ADVISOR). The performance of these vehicles is analyzed on the bases of energy consumption and greenhouse gas emissions on the tank-to-wheel and well-to-wheel paths. Both city and highway driving conditions are considered during the simulation. When simulated on the well-to-wheel path, it is shown that the range extender with a Wankel rotary engine consumes less energy and emits fewer greenhouse gases compared to the other systems with reciprocating engines during many driving cycles. The rotary engine has a higher power-to-weight ratio and lower noise, vibration and harshness compared to conventional reciprocating engines, although performs less efficiently. The benefits of a Wankel engine make it an attractive option for use as a range extender in a plug-in hybrid electric vehicle.

  10. Acoustic-based proton range verification in heterogeneous tissue: simulation studies

    Science.gov (United States)

    Jones, Kevin C.; Nie, Wei; Chu, James C. H.; Turian, Julius V.; Kassaee, Alireza; Sehgal, Chandra M.; Avery, Stephen

    2018-01-01

    Acoustic-based proton range verification (protoacoustics) is a potential in vivo technique for determining the Bragg peak position. Previous measurements and simulations have been restricted to homogeneous water tanks. Here, a CT-based simulation method is proposed and applied to a liver and prostate case to model the effects of tissue heterogeneity on the protoacoustic amplitude and time-of-flight range verification accuracy. For the liver case, posterior irradiation with a single proton pencil beam was simulated for detectors placed on the skin. In the prostate case, a transrectal probe measured the protoacoustic pressure generated by irradiation with five separate anterior proton beams. After calculating the proton beam dose deposition, each CT voxel’s material properties were mapped based on Hounsfield Unit values, and thermoacoustically-generated acoustic wave propagation was simulated with the k-Wave MATLAB toolbox. By comparing the simulation results for the original liver CT to homogenized variants, the effects of heterogeneity were assessed. For the liver case, 1.4 cGy of dose at the Bragg peak generated 50 mPa of pressure (13 cm distal), a 2×  lower amplitude than simulated in a homogeneous water tank. Protoacoustic triangulation of the Bragg peak based on multiple detector measurements resulted in 0.4 mm accuracy for a δ-function proton pulse irradiation of the liver. For the prostate case, higher amplitudes are simulated (92–1004 mPa) for closer detectors (verification to heterogeneous tissue will result in decreased signal amplitudes relative to homogeneous water tank measurements, but accurate range verification is still expected to be possible.

  11. Lightweight Investigation of Extended-Range Electric Vehicle Based on Collision Failure Using Numerical Simulation

    Directory of Open Access Journals (Sweden)

    Jiangqi Long

    2015-01-01

    Full Text Available The total weight of Extended-Range Electric Vehicle (E-REV is too heavy, which affects rear-end collision safety. Using numerical simulation, a lightweight method is designed to reduce E-REV body and key parts weight based on rear-end collision failure analysis. To calculate and optimize the performance of vehicle safety, the simulation model of E-REV rear-end collision safety is built by using finite element analysis. Drive battery pack lightweight design method is analyzed and the bending mode and torsional mode of E-REV before and after lightweight are compared to evaluate E-REV rear-end collision safety performance. The simulation results of optimized E-REV safety structure are verified by both numerical simulation and experimental investigation of the entire vehicle crash test.

  12. Defense Waste Processing Facility Simulant Chemical Processing Cell Studies for Sludge Batch 9

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Tara E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Newell, J. David [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Woodham, Wesley H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-08-10

    The Savannah River National Laboratory (SRNL) received a technical task request from Defense Waste Processing Facility (DWPF) and Saltstone Engineering to perform simulant tests to support the qualification of Sludge Batch 9 (SB9) and to develop the flowsheet for SB9 in the DWPF. These efforts pertained to the DWPF Chemical Process Cell (CPC). CPC experiments were performed using SB9 simulant (SB9A) to qualify SB9 for sludge-only and coupled processing using the nitric-formic flowsheet in the DWPF. Two simulant batches were prepared, one representing SB8 Tank 40H and another representing SB9 Tank 51H. The simulant used for SB9 qualification testing was prepared by blending the SB8 Tank 40H and SB9 Tank 51H simulants. The blended simulant is referred to as SB9A. Eleven CPC experiments were run with an acid stoichiometry ranging between 105% and 145% of the Koopman minimum acid equation (KMA), which is equivalent to 109.7% and 151.5% of the Hsu minimum acid factor. Three runs were performed in the 1L laboratory scale setup, whereas the remainder were in the 4L laboratory scale setup. Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) cycles were performed on nine of the eleven. The other two were SRAT cycles only. One coupled flowsheet and one extended run were performed for SRAT and SME processing. Samples of the condensate, sludge, and off-gas were taken to monitor the chemistry of the CPC experiments.

  13. A General Method for Large Eddy Simulation in Different Range of Turbulent Flows

    CERN Document Server

    Yu, Changping

    2012-01-01

    Traditional large eddy simulation is based on Kolmogrov's hypothesis, and done in the inertial range. In inertial range the LES model coefficient is scale-invariant. In many cases, such as computing in the boundary layer, the filter scale is not in the inertial range, and the model coefficient changes drastically with the filter scale, thus the assumption of scale-invariance is not proper. In this paper, we propose a general principle of constraint, and then we deduce two concrete constraints based on the existing spectrum theory and priori data. The constrained dynamic Smogorinsky model can predict energy spectrum well in different range of forced and decayed turbulence. Dynamic mixed models with one of the constraints shows more efficient than some classical models in predicting energy spectrum and SGS dissipation, and also displays a strong correlation with the real stress in different range of the turbulent flows.

  14. Short-range energy budget simulator of single photon lidar demonstrator

    Science.gov (United States)

    Murtazin, Mark V.; Prochazka, Ivan; Blazej, Josef; Pershin, Sergey M.; Lednev, Vasily N.

    2017-05-01

    The compact single photon lidar demonstrator dedicated for asteroid rendezvous missions has been designed and realized in our laboratory two years ago. The instrument provides crucial data on altitude and terrain profile for altitudes exceeding 5 km with a precision of less than 10 cm fulfilling the Rayleigh criterion. One of the calibration procedure of demonstrator is the positioning of receiver and transmitter optics related to detector and laser and the aligning of transmitter and receiver optical common paths. To improve this particular indoor calibration procedure the new simulator of single photon energy budget during short range operation has been created. The comparison of simulated and experimental data will be presented and discussed.

  15. Calibrating and testing a gap model for simulating forest management in the Oregon Coast Range

    Science.gov (United States)

    Pabst, R.J.; Goslin, M.N.; Garman, S.L.; Spies, T.A.

    2008-01-01

    The complex mix of economic and ecological objectives facing today's forest managers necessitates the development of growth models with a capacity for simulating a wide range of forest conditions while producing outputs useful for economic analyses. We calibrated the gap model ZELIG to simulate stand-level forest development in the Oregon Coast Range as part of a landscape-scale assessment of different forest management strategies. Our goal was to incorporate the predictive ability of an empirical model with the flexibility of a forest succession model. We emphasized the development of commercial-aged stands of Douglas-fir, the dominant tree species in the study area and primary source of timber. In addition, we judged that the ecological approach of ZELIG would be robust to the variety of other forest conditions and practices encountered in the Coast Range, including mixed-species stands, small-scale gap formation, innovative silvicultural methods, and reserve areas where forests grow unmanaged for long periods of time. We parameterized the model to distinguish forest development among two ecoregions, three forest types and two site productivity classes using three data sources: chronosequences of forest inventory data, long-term research data, and simulations from an empirical growth-and-yield model. The calibrated model was tested with independent, long-term measurements from 11 Douglas-fir plots (6 unthinned, 5 thinned), 3 spruce-hemlock plots, and 1 red alder plot. ZELIG closely approximated developmental trajectories of basal area and large trees in the Douglas-fir plots. Differences between simulated and observed conifer basal area for these plots ranged from -2.6 to 2.4 m2/ha; differences in the number of trees/ha ???50 cm dbh ranged from -8.8 to 7.3 tph. Achieving these results required the use of a diameter-growth multiplier, suggesting some underlying constraints on tree growth such as the temperature response function. ZELIG also tended to overestimate

  16. Spatial simulation exploring pattern and process

    CERN Document Server

    O'Sullivan, David

    2013-01-01

    A ground-up approach to explaining dynamic social modelling for an interdisciplinary audience. Across broad areas of the environmental and social sciences, simulation models are  an important way to study systems inaccessible to scientific experimental and observational methods, and also an essential complement to those more conventional approaches.  The contemporary research literature is teeming with abstract simulation models whose presentation is mathematically demanding and requires a high level of knowledge of quantitative and computational methods and approaches.  Furthermore, simulat

  17. Simulation of heavy, long-term rainfall over low mountain ranges; Simulation von Starkniederschlaegen mit langer Andauer ueber Mittelgebirgen

    Energy Technology Data Exchange (ETDEWEB)

    Kunz, M.

    2003-03-01

    A diagnostic model for the estimation of orographic precipitation during large-scale upslide motions is presented. It is based on linear theory for 3-D mountain overflow. From the simulated vertical velocities rain intensities at the ground are calculated using a model for precipitation formation. Due to the small number of free parameters and because of the simple initialisation method, e.g. with single radiosonde data, the model is used for regionalisation of precipitation from rain gauge observations as well as for deriving its statistics under dynamical constraints. For Southwest Germany and Eastern France, with the low mountain ranges of the Vosges, Black Forest and Swabian Alb, model simulations are performed for individual events with heavy rainfall. Thereby it is evaluated, how realistic rainfall patterns can be obtained with a combination of model simulations and measurement data. Mean rainfall distributions are derived from simulations of all extreme events with 24-h totals over 60 mm at selected rain gauge stations between 1971 and 2000. Furthermore the calculation of rain sums for different return periods is performed using extreme value statistics. So it is possible to quantify the hazard potential of heavy rainfall, which may cause flooding or landslides, in high spatial resolution (2.5 x 2.5 km). (orig.)

  18. 3D range-modulator for scanned particle therapy: development, Monte Carlo simulations and experimental evaluation

    Science.gov (United States)

    Simeonov, Yuri; Weber, Uli; Penchev, Petar; Printz Ringbæk, Toke; Schuy, Christoph; Brons, Stephan; Engenhart-Cabillic, Rita; Bliedtner, Jens; Zink, Klemens

    2017-09-01

    The purpose of this work was to design and manufacture a 3D range-modulator for scanned particle therapy. The modulator is intended to create a highly conformal dose distribution with only one fixed energy, simultaneously reducing considerably the treatment time. As a proof of concept, a 3D range-modulator was developed for a spherical target volume with a diameter of 5 cm, placed at a depth of 25 cm in a water phantom. It consists of a large number of thin pins with a well-defined shape and different lengths to modulate the necessary shift of the Bragg peak. The 3D range-modulator was manufactured with a rapid prototyping technique. The FLUKA Monte Carlo package was used to simulate the modulating effect of the 3D range-modulator and the resulting dose distribution. For that purpose, a special user routine was implemented to handle its complex geometrical contour. Additionally, FLUKA was extended with the capability of intensity modulated scanning. To validate the simulation results, dose measurements were carried out at the Heidelberg Ion Beam Therapy Center with a 400.41 MeV/u 12C beam. The high resolution dosimetric measurements show a good agreement between simulated and measured dose distributions. Irradiation of the monoenergetic raster plan took 3 s, which is approximately 20 times shorter than a comparable plan with 16 different energies. The combination of only one energy and a 3D range-modulator leads to a tremendous decrease in irradiation time. ‘Interplay effects’, typical for moving targets and pencil beam scanning, can be immensely reduced or disappear completely, making the delivery of a homogeneous dose to moving targets more reliable. Combining high dose conformity, very good homogeneity and extremely short irradiation times, the 3D range-modulator is considered to become a clinically applicable method for very fast treatment of lung tumours.

  19. Process simulation for advanced composites production

    Energy Technology Data Exchange (ETDEWEB)

    Allendorf, M.D.; Ferko, S.M.; Griffiths, S. [Sandia National Labs., Livermore, CA (United States)] [and others

    1997-04-01

    The objective of this project is to improve the efficiency and lower the cost of chemical vapor deposition (CVD) processes used to manufacture advanced ceramics by providing the physical and chemical understanding necessary to optimize and control these processes. Project deliverables include: numerical process models; databases of thermodynamic and kinetic information related to the deposition process; and process sensors and software algorithms that can be used for process control. Target manufacturing techniques include CVD fiber coating technologies (used to deposit interfacial coatings on continuous fiber ceramic preforms), chemical vapor infiltration, thin-film deposition processes used in the glass industry, and coating techniques used to deposit wear-, abrasion-, and corrosion-resistant coatings for use in the pulp and paper, metals processing, and aluminum industries.

  20. Role of computational efficiency in process simulation

    Directory of Open Access Journals (Sweden)

    Kurt Strand

    1989-07-01

    Full Text Available It is demonstrated how efficient numerical algorithms may be combined to yield a powerful environment for analysing and simulating dynamic systems. The importance of using efficient numerical algorithms is emphasized and demonstrated through examples from the petrochemical industry.

  1. A Process for Comparing Dynamics of Distributed Space Systems Simulations

    Science.gov (United States)

    Cures, Edwin Z.; Jackson, Albert A.; Morris, Jeffery C.

    2009-01-01

    The paper describes a process that was developed for comparing the primary orbital dynamics behavior between space systems distributed simulations. This process is used to characterize and understand the fundamental fidelities and compatibilities of the modeling of orbital dynamics between spacecraft simulations. This is required for high-latency distributed simulations such as NASA s Integrated Mission Simulation and must be understood when reporting results from simulation executions. This paper presents 10 principal comparison tests along with their rationale and examples of the results. The Integrated Mission Simulation (IMSim) (formerly know as the Distributed Space Exploration Simulation (DSES)) is a NASA research and development project focusing on the technologies and processes that are related to the collaborative simulation of complex space systems involved in the exploration of our solar system. Currently, the NASA centers that are actively participating in the IMSim project are the Ames Research Center, the Jet Propulsion Laboratory (JPL), the Johnson Space Center (JSC), the Kennedy Space Center, the Langley Research Center and the Marshall Space Flight Center. In concept, each center participating in IMSim has its own set of simulation models and environment(s). These simulation tools are used to build the various simulation products that are used for scientific investigation, engineering analysis, system design, training, planning, operations and more. Working individually, these production simulations provide important data to various NASA projects.

  2. Multiple Constraints Based Robust Matching of Poor-Texture Close-Range Images for Monitoring a Simulated Landslide

    Directory of Open Access Journals (Sweden)

    Gang Qiao

    2016-05-01

    Full Text Available Landslides are one of the most destructive geo-hazards that can bring about great threats to both human lives and infrastructures. Landslide monitoring has been always a research hotspot. In particular, landslide simulation experimentation is an effective tool in landslide research to obtain critical parameters that help understand the mechanism and evaluate the triggering and controlling factors of slope failure. Compared with other traditional geotechnical monitoring approaches, the close-range photogrammetry technique shows potential in tracking and recording the 3D surface deformation and failure processes. In such cases, image matching usually plays a critical role in stereo image processing for the 3D geometric reconstruction. However, the complex imaging conditions such as rainfall, mass movement, illumination, and ponding will reduce the texture quality of the stereo images, bringing about difficulties in the image matching process and resulting in very sparse matches. To address this problem, this paper presents a multiple-constraints based robust image matching approach for poor-texture close-range images particularly useful in monitoring a simulated landslide. The Scale Invariant Feature Transform (SIFT algorithm was first applied to the stereo images for generation of scale-invariate feature points, followed by a two-step matching process: feature-based image matching and area-based image matching. In the first feature-based matching step, the triangulation process was performed based on the SIFT matches filtered by the Fundamental Matrix (FM and a robust checking procedure, to serve as the basic constraints for feature-based iterated matching of all the non-matched SIFT-derived feature points inside each triangle. In the following area-based image-matching step, the corresponding points of the non-matched features in each triangle of the master image were predicted in the homologous triangle of the searching image by using geometric

  3. Simulation of Friction Stir Processing in 304L Stainless Steel

    Directory of Open Access Journals (Sweden)

    Miles M.P.

    2016-01-01

    Full Text Available A major dilemma facing the nuclear industry is repair or replacement of stainless steel reactor components that have been exposed to neutron irradiation. When conventional fusion welding is used for weld repair, the high temperatures and thermal stresses inherent in the process enhance the growth of helium bubbles, causing intergranular cracking in the heat-affected zone (HAZ. Friction stir processing (FSP has potential as a weld repair technique for irradiated stainless steel, because it operates at much lower temperatures than fusion welding, and is therefore less likely to cause cracking in the HAZ. Numerical simulation of the FSP process in 304L stainless steel was performed using an Eulerian finite element approach. Model input required flow stresses for the large range of strain rates and temperatures inherent in the FSP process. Temperature predictions in three locations adjacent to the stir zone were accurate to within 4% of experimentally measure values. Prediction of recrystallized grain size at a location about 6mm behind the tool center was less accurate, because the empirical model employed for the prediction did not account for grain growth that occurred after deformation in the experiment was halted.

  4. Simulation-based optimization for product and process design

    NARCIS (Netherlands)

    Driessen, L.

    2006-01-01

    The design of products and processes has gradually shifted from a purely physical process towards a process that heavily relies on computer simulations (virtual prototyping). To optimize this virtual design process in terms of speed and final product quality, statistical methods and mathematical

  5. Arabidopsis Growth Simulation Using Image Processing Technology

    Directory of Open Access Journals (Sweden)

    Junmei Zhang

    2014-01-01

    Full Text Available This paper aims to provide a method to represent the virtual Arabidopsis plant at each growth stage. It includes simulating the shape and providing growth parameters. The shape is described with elliptic Fourier descriptors. First, the plant is segmented from the background with the chromatic coordinates. With the segmentation result, the outer boundary series are obtained by using boundary tracking algorithm. The elliptic Fourier analysis is then carried out to extract the coefficients of the contour. The coefficients require less storage than the original contour points and can be used to simulate the shape of the plant. The growth parameters include total area and the number of leaves of the plant. The total area is obtained with the number of the plant pixels and the image calibration result. The number of leaves is derived by detecting the apex of each leaf. It is achieved by using wavelet transform to identify the local maximum of the distance signal between the contour points and the region centroid. Experiment result shows that this method can record the growth stage of Arabidopsis plant with fewer data and provide a visual platform for plant growth research.

  6. A Software Development Simulation Model of a Spiral Process

    Science.gov (United States)

    Mizell, Carolyn; Malone, Linda

    2007-01-01

    There is a need for simulation models of software development processes other than the waterfall because processes such as spiral development are becoming more and more popular. The use of a spiral process can make the inherently difficult job of cost and schedule estimation even more challenging due to its evolutionary nature, but this allows for a more flexible process that can better meet customers' needs. This paper will present a discrete event simulation model of spiral development that can be used to analyze cost and schedule effects of using such a process in comparison to a waterfall process.

  7. Dependence of simulations of long range transport on meteorology, model and dust size

    Science.gov (United States)

    Mahowald, N. M.; Albani, S.; Smith, M.; Losno, R.; Marticorena, B.; Ridley, D. A.; Heald, C. L.; Qu, Z.

    2015-12-01

    Mineral aerosols interact with radiation directly, as well as modifying climate, and provide important micronutrients to ocean and land ecosystems. Mineral aerosols are transported long distances from the source regions to remote regions, but the rates at which this occurs can be difficult to deduce from either observations or models. Here we consider interactions between the details of the simulation of dust size and long-range transport. In addition, we compare simulations of dust using multiple reanalysis datasets, as well as different model basis to understand how robust the mean, seasonality and interannual variability are in models. Models can provide insight into how long observations are required in order to characterize the atmospheric concentration and deposition to remote regions.

  8. A computer code simulating multistage chemical exchange column under wide range of operating conditions

    Energy Technology Data Exchange (ETDEWEB)

    Yamanishi, Toshihiko; Okuno, Kenji [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    1996-09-01

    A computer code has been developed to simulate a multistage CECE(Combined Electrolysis Chemical Exchange) column. The solution of basic equations can be found out by the Newton-Raphson method. The independent variables are the atom fractions of D and T in each stage for the case where H is dominant within the column. These variables are replaced by those of H and T under the condition that D is dominant. Some effective techniques have also been developed to get a set of solutions of the basic equations: a setting procedure of initial values of the independent variables; and a procedure for the convergence of the Newton-Raphson method. The computer code allows us to simulate the column behavior under a wide range of the operating conditions. Even for a severe case, where the dominant species changes along the column height, the code can give a set of solutions of the basic equations. (author)

  9. A method for simulating the atmospheric entry of long-range ballistic missiles

    Science.gov (United States)

    Eggers, A J , Jr

    1958-01-01

    It is demonstrated with the aid of similitude arguments that a model launched from a hypervelocity gun upstream through a special supersonic nozzle should experience aerodynamic heating and resulting thermal stresses like those encountered by a long-range ballistic missile entering the earth's atmosphere. This demonstration hinges on the requirements that model and missile be geometrically similar and made of the same material, and that they have the same flight speed and Reynolds number (based on conditions just outside the boundary layer) at corresponding points in their trajectories. The hypervelocity gun provides the model with the required initial speed, while the nozzle scales the atmosphere, in terms of density variation, to provide the model with speeds and Reynolds numbers over its entire trajectory. Since both the motion and aerodynamic heating of a missile tend to be simulated in the model tests, this combination of hypervelocity gun and supersonic nozzle is termed an atmosphere entry simulator.

  10. Simulating threshold voltage shift of MOS devices due to radiation in the low-dose range

    CERN Document Server

    Wan Xin Heng; Gao Wen Yu; Huang Ru; Wang Yang Yuan

    2002-01-01

    An analytical MOSFET threshold voltage shift model due to radiation in the low-dose range has been developed for circuit simulations. Experimental data in the literature shows that the model predictions are in good agreement. It is simple in functional form and hence computationally efficient. It can be used as a basic circuit simulation tool for analysing MOSFET exposed to a nuclear environment up to about 1 Mrad(Si). In accordance with common believe, radiation induced absolute change of threshold voltage was found to be larger in irradiated PMOS devices. However, if the radiation sensitivity is defined in the way authors did it, the results indicated NMOS rather than PMOS devices are more sensitive, specially at low doses. This is important from the standpoint of their possible application in dosimetry

  11. Biomedical Simulation Models of Human Auditory Processes

    Science.gov (United States)

    Bicak, Mehmet M. A.

    2012-01-01

    Detailed acoustic engineering models that explore noise propagation mechanisms associated with noise attenuation and transmission paths created when using hearing protectors such as earplugs and headsets in high noise environments. Biomedical finite element (FE) models are developed based on volume Computed Tomography scan data which provides explicit external ear, ear canal, middle ear ossicular bones and cochlea geometry. Results from these studies have enabled a greater understanding of hearing protector to flesh dynamics as well as prioritizing noise propagation mechanisms. Prioritization of noise mechanisms can form an essential framework for exploration of new design principles and methods in both earplug and earcup applications. These models are currently being used in development of a novel hearing protection evaluation system that can provide experimentally correlated psychoacoustic noise attenuation. Moreover, these FE models can be used to simulate the effects of blast related impulse noise on human auditory mechanisms and brain tissue.

  12. The Simulation and Analysis of the Closed Die Hot Forging Process by A Computer Simulation Method

    Directory of Open Access Journals (Sweden)

    Dipakkumar Gohil

    2012-06-01

    Full Text Available The objective of this research work is to study the variation of various parameters such as stress, strain, temperature, force, etc. during the closed die hot forging process. A computer simulation modeling approach has been adopted to transform the theoretical aspects in to a computer algorithm which would be used to simulate and analyze the closed die hot forging process. For the purpose of process study, the entire deformation process has been divided in to finite number of steps appropriately and then the output values have been computed at each deformation step. The results of simulation have been graphically represented and suitable corrective measures are also recommended, if the simulation results do not agree with the theoretical values. This computer simulation approach would significantly improve the productivity and reduce the energy consumption of the overall process for the components which are manufactured by the closed die forging process and contribute towards the efforts in reducing the global warming.

  13. 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

    2011-03-15

    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.

  14. Modeling and simulation of membrane process

    Science.gov (United States)

    Staszak, Maciej

    2017-06-01

    The article presents the different approaches to polymer membrane mathematical modeling. Traditional models based on experimental physicochemical correlations and balance models are presented in the first part. Quantum and molecular mechanics models are presented as they are more popular for polymer membranes in fuel cells. The initial part is enclosed by neural network models which found their use for different types of processes in polymer membranes. The second part is devoted to models of fluid dynamics. The computational fluid dynamics technique can be divided into solving of Navier-Stokes equations and into Boltzmann lattice models. Both approaches are presented focusing on membrane processes.

  15. When teams shift among processes: insights from simulation and optimization.

    Science.gov (United States)

    Kennedy, Deanna M; McComb, Sara A

    2014-09-01

    This article introduces process shifts to study the temporal interplay among transition and action processes espoused in the recurring phase model proposed by Marks, Mathieu, and Zacarro (2001). Process shifts are those points in time when teams complete a focal process and change to another process. By using team communication patterns to measure process shifts, this research explores (a) when teams shift among different transition processes and initiate action processes and (b) the potential of different interventions, such as communication directives, to manipulate process shift timing and order and, ultimately, team performance. Virtual experiments are employed to compare data from observed laboratory teams not receiving interventions, simulated teams receiving interventions, and optimal simulated teams generated using genetic algorithm procedures. Our results offer insights about the potential for different interventions to affect team performance. Moreover, certain interventions may promote discussions about key issues (e.g., tactical strategies) and facilitate shifting among transition processes in a manner that emulates optimal simulated teams' communication patterns. Thus, we contribute to theory regarding team processes in 2 important ways. First, we present process shifts as a way to explore the timing of when teams shift from transition to action processes. Second, we use virtual experimentation to identify those interventions with the greatest potential to affect performance by changing when teams shift among processes. Additionally, we employ computational methods including neural networks, simulation, and optimization, thereby demonstrating their applicability in conducting team research. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  16. Simulation and Optimization of Foam EOR Processes

    NARCIS (Netherlands)

    Namdar Zanganeh, M.

    2011-01-01

    Chemical enhanced oil recovery (EOR) is relatively expensive due to the high cost of the injected chemicals such as surfactants. Excessive use of these chemicals leads to processes that are not economically feasible. Therefore, optimizing the volume of these injected chemicals is of extreme

  17. Optimizing Single Sweep Range and Doppler Processing for FMCW Radar using Inverse Filtering

    NARCIS (Netherlands)

    Jong, A.J. de; Dorp, Ph. van

    2005-01-01

    We discuss range and Doppler processing for FMCW radar using only a single pulse or frequency sweep. The first step is correlation processing, for which the range and Doppler resolution are limited by the ambiguity function. We show that this resolution can be optimized with an additional inverse

  18. Software quality and process improvement in scientific simulation codes

    Energy Technology Data Exchange (ETDEWEB)

    Ambrosiano, J.; Webster, R. [Los Alamos National Lab., NM (United States)

    1997-11-01

    This report contains viewgraphs on the quest to develope better simulation code quality through process modeling and improvement. This study is based on the experience of the authors and interviews with ten subjects chosen from simulation code development teams at LANL. This study is descriptive rather than scientific.

  19. Organisational learning via Interactive Process Simulation in AGE

    NARCIS (Netherlands)

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

    2007-01-01

    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

  20. [Absorption Characteristics and Simulation of LLM-105 in the Terahertz Range].

    Science.gov (United States)

    Meng, Zeng-rui; Shang, Li-ping; Du, Yu; Deng, Hu

    2015-07-01

    2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105), a novel explosive with high energy and low sensibility. In order to study the molecular structure characteristics of the explosive, the absorption spectra of LLM-105 in the frequency range of 0.2-2.4 THz were detected by terahertz time-domain spectroscopy (THz-TDS). The results showed that a number of characteristic absorption peaks with different intensity located at 1.27, 1.59, 2.00, 2.08, 2.20, 2.29 THz. The article also simulated the absorption spectra of LLM-105 molecular crystal within 0.2-2.5 THz region by using Materials Studio 6.0 software based on density functional theory (DFT), and the simulated results agreed well with the experimental data except for the peak at 2.29 THz, which verified theoretically the accuracy of the experimental data. In addition, the vibrational modes of the characteristic peaks in the experimental absorption spectra were analyzed and identified, the results showed that the forming of the characteristic absorption peaks and the molecular vibration were closely related, which further provided important laboratory and technology support for the study of the transformation of molecule structure of LLM-105. There was no simulated frequency agreed with the experimental absorption peak at 2.29 THz, which may be caused by the vibration of the crystal lattice or other reasons.

  1. Numerical simulation of hydrothermal circulation in the Cascade Range, north-central Oregon

    Science.gov (United States)

    Ingebritsen, S.E.; Paulson, K.M.

    1990-01-01

    Alternate conceptual models to explain near-surface heat-flow observations in the central Oregon Cascade Range involve (1) an extensive mid-crustal magmatic heat source underlying both the Quaternary arc and adjacent older rocks or (2) a narrower deep heat source which is flanked by a relatively shallow conductive heat-flow anomaly caused by regional ground-water flow (the lateral-flow model). Relative to the mid-crustal heat source model, the lateral-flow model suggests a more limited geothermal resource base, but a better-defined exploration target. We simulated ground-water flow and heat transport through two cross sections trending west from the Cascade range crest in order to explore the implications of the two models. The thermal input for the alternate conceptual models was simulated by varying the width and intensity of a basal heat-flow anomaly and, in some cases, by introducing shallower heat sources beneath the Quaternary arc. Near-surface observations in the Breitenbush Hot Springs area are most readily explained in terms of lateral heat transport by regional ground-water flow; however, the deep thermal structure still cannot be uniquely inferred. The sparser thermal data set from the McKenzie River area can be explained either in terms of deep regional ground-water flow or in terms of a conduction-dominated system, with ground-water flow essentially confined to Quaternary rocks and fault zones.

  2. Mathematic simulation of high-efficiency process of grain cleaning

    Science.gov (United States)

    Galyautdinova, Y. V.; Gaysin, I. A.; Samigullin, A. D.; Samigullina, A. R.; Galyautdinov, R. R.

    2017-09-01

    The article presents the results of field experiment and the results of computer simulation of the grain cleaning process pneumosorting machine PSM-0,5. The results of the comparison of two methods of research are presented.

  3. Dynamic simulation of concentrated macromolecular solutions with screened long-range hydrodynamic interactions: algorithm and limitations.

    Science.gov (United States)

    Ando, Tadashi; Chow, Edmond; Skolnick, Jeffrey

    2013-09-28

    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

  4. Two-stage ionoacoustic range verification leveraging Monte Carlo and acoustic simulations to stably account for tissue inhomogeneity and accelerator-specific time structure - A simulation study.

    Science.gov (United States)

    Patch, Sarah K; Hoff, Daniel E M; Webb, Tyler B; Sobotka, Lee G; Zhao, Tianyu

    2018-02-01

    Range errors constrain treatment planning by limiting choice of ion beam angles and requiring large margins. Ionoacoustic range verification requires recovering the location of an acoustic source from low frequency signals. A priori information is applied to stably overcome resolution limits of inverse acoustic source imaging in this simulation study. In particular, the accuracy and robustness of ionoacoustic range verification for lateral and oblique delivery of high-energy protons to the prostate is examined. Dose maps were computed using GEANT4 Monte Carlo simulations via the TOPAS user interface. Thermoacoustic pulses were propagated using k-Wave software, with initial pressures corresponding to instantaneous dose deposition and piecewise constant maps of tissue properties derived from the planning CT. A database of dose maps with corresponding thermoacoustic emissions and Bragg peak locations, referred to as "control points," were precomputed. Corresponding thermoacoustic emissions were also precomputed. Pulses were recorded at four coplanar locations corresponding to the outer surface of a virtual transrectal array. To model experimental beam delivery, k-Wave results were convolved in time with a Gaussian envelope to account for noninstantaneous proton delivery by a synchrocyclotron. Thermoacoustic pulses were bandlimited below 150 kHz, and amplitudes were directly proportional to charge delivered. To test robustness of our method, white noise was added. Range was estimated in a two-step process. The first step obtained a preliminary range estimate by one-way beamforming. The second step was taken using data corresponding to the "control point" nearest to the preliminary range estimate. For each receiver, the time of flight difference, ∆t, between the measured and control thermoacoustic signals were accurately estimated by applying the Fourier shift theorem. Receiver-Bragg peak distance was then estimated by adding vs ∆t to the known distance of the

  5. Fermentation Process Simulation of Homebrewing Beer

    Directory of Open Access Journals (Sweden)

    Garduño-García A.

    2014-04-01

    Full Text Available The goal of the current research was to study the behavior of the fermentation process of home-made beer using a mathematical dynamic model. The model contains the rates of change of the concentration state variables of glucose, maltose and maltotriose. An output variable is the ethanol concentration and an auxiliary variable is the biomass (yeast concentration. The model was programmed in the Matlab-Simulink environment, and for its numerical integration Dormand-Prince method of fourth order with a variable integration step size and a relative tolerance of was used. In order to know which model parameters are more important, a local sensitivity analysis was carried out. Furthermore, an experiment was performed to produce home-made beer at constant temperature (21°C. Fourteen experimental units (fermenters with the same initial conditions were implemented. Using the experimental results the model was calibrated by nonlinear least squares and differential evolution algorithms. According to the statistics bias (BIAS, correlation coefficient (r, squared root of mean squared error (RMSE, mean absolute error (MAE and the efficiency of modeling (EF, a good fit between the model predictions and measurements were found after the model parameters estimation.

  6. A state-and-transition simulation modeling approach for estimating the historical range of variability

    Directory of Open Access Journals (Sweden)

    Kori Blankenship

    2015-04-01

    Full Text Available Reference ecological conditions offer important context for land managers as they assess the condition of their landscapes and provide benchmarks for desired future conditions. State-and-transition simulation models (STSMs are commonly used to estimate reference conditions that can be used to evaluate current ecosystem conditions and to guide land management decisions and activities. The LANDFIRE program created more than 1,000 STSMs and used them to assess departure from a mean reference value for ecosystems in the United States. While the mean provides a useful benchmark, land managers and researchers are often interested in the range of variability around the mean. This range, frequently referred to as the historical range of variability (HRV, offers model users improved understanding of ecosystem function, more information with which to evaluate ecosystem change and potentially greater flexibility in management options. We developed a method for using LANDFIRE STSMs to estimate the HRV around the mean reference condition for each model state in ecosystems by varying the fire probabilities. The approach is flexible and can be adapted for use in a variety of ecosystems. HRV analysis can be combined with other information to help guide complex land management decisions.

  7. Simulation on Control Chart in Monitoring the Multivariate Process Variability

    OpenAIRE

    Sunusi, Nurtiti

    2017-01-01

    - Abstract. Control chart used to monitor shifts in the process mean and variability for multivariate data. This paper aims to monitor process variability through chart. Process variability observed by used the determinant of the sample covariance matrix, which is called . The result of this paper show that the improved chart is more sensitive to shifts in the process variability. The standard chart has a bigger ARL than the improved chart by simulation.

  8. Ergonomics and simulation tools for service & industrial process improvement

    Science.gov (United States)

    Sánchez, A.; García, M.

    2012-04-01

    Human interaction within designed processes is a really important factor in how efficiently any process will operate. How a human will function in relation to a process is not easy to predict. All the ergonomic considerations traditionally have been evaluated outside of the 3D product design. Nowadays technologies of 3D process design and simulation tools give us this opportunity from the earliest stages of the design process. Also they can be used to improve current process in order to increase human comfort, productivity and safety. This work shows a methodology using 3D design and simulation tools to improve industrial and service process. This methodology has as an objective the detection, evaluation, control of work-related musculoskeletal disorders (WMSDs).

  9. Optical properties of dental restorative materials in the wavelength range 400 to 700 nm for the simulation of color perception.

    Science.gov (United States)

    Friebel, Moritz; Povel, Kirsten; Cappius, Hans-Joachim; Helfmann, Jürgen; Meinke, Martina

    2009-01-01

    Aesthetic restorations require dental restorative materials to have optical properties very similar to those of the teeth. A method is developed to this end to determine the optical parameters absorption coefficient mu(a), scattering coefficient mu(s), anisotropy factor g, and effective scattering coefficient mu(s) (') of dental restorative materials. The method includes sample preparation and measurements of transmittance and reflectance in an integrating sphere spectrometer followed by inverse Monte Carlo simulations. Using this method the intrinsic optical parameters are determined for shade B2 of the light-activated composites TPH((R)) Spectrum, Esthet-X, and the Ormocer Definite in the wavelength range 400 to 700 nm. By using the determined parameters mu(a), mu(s), and g together with an appropriate phase function, the reflectance of samples with 1-mm layer thickness and shade B2 could be predicted with a very high degree of accuracy using a forward Monte Carlo simulation. The color perception was calculated from the simulated reflectance according to the CIELAB system. We initiate the compilation of a data pool of optical parameters that in the future will enable calculation models to be used as a basis for optimization of the optical approximation of the natural tooth, and the composition of new materials and their production process.

  10. Optical properties of dental restorative materials in the wavelength range 400 to 700 nm for the simulation of color perception

    Science.gov (United States)

    Friebel, Moritz; Povel, Kirsten; Cappius, Hans-Joachim; Helfmann, Jürgen; Meinke, Martina

    2009-09-01

    Aesthetic restorations require dental restorative materials to have optical properties very similar to those of the teeth. A method is developed to this end to determine the optical parameters absorption coefficient μa, scattering coefficient μs, anisotropy factor g, and effective scattering coefficient μs' of dental restorative materials. The method includes sample preparation and measurements of transmittance and reflectance in an integrating sphere spectrometer followed by inverse Monte Carlo simulations. Using this method the intrinsic optical parameters are determined for shade B2 of the light-activated composites TPH® Spectrum®, Esthet-X®, and the Ormocer® Definite® in the wavelength range 400 to 700 nm. By using the determined parameters μa, μs, and g together with an appropriate phase function, the reflectance of samples with 1-mm layer thickness and shade B2 could be predicted with a very high degree of accuracy using a forward Monte Carlo simulation. The color perception was calculated from the simulated reflectance according to the CIELAB system. We initiate the compilation of a data pool of optical parameters that in the future will enable calculation models to be used as a basis for optimization of the optical approximation of the natural tooth, and the composition of new materials and their production process.

  11. IMPROVING TACONITE PROCESSING PLANT EFFICIENCY BY COMPUTER SIMULATION, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    William M. Bond; Salih Ersayin

    2007-03-30

    This project involved industrial scale testing of a mineral processing simulator to improve the efficiency of a taconite processing plant, namely the Minorca mine. The Concentrator Modeling Center at the Coleraine Minerals Research Laboratory, University of Minnesota Duluth, enhanced the capabilities of available software, Usim Pac, by developing mathematical models needed for accurate simulation of taconite plants. This project provided funding for this technology to prove itself in the industrial environment. As the first step, data representing existing plant conditions were collected by sampling and sample analysis. Data were then balanced and provided a basis for assessing the efficiency of individual devices and the plant, and also for performing simulations aimed at improving plant efficiency. Performance evaluation served as a guide in developing alternative process strategies for more efficient production. A large number of computer simulations were then performed to quantify the benefits and effects of implementing these alternative schemes. Modification of makeup ball size was selected as the most feasible option for the target performance improvement. This was combined with replacement of existing hydrocyclones with more efficient ones. After plant implementation of these modifications, plant sampling surveys were carried out to validate findings of the simulation-based study. Plant data showed very good agreement with the simulated data, confirming results of simulation. After the implementation of modifications in the plant, several upstream bottlenecks became visible. Despite these bottlenecks limiting full capacity, concentrator energy improvement of 7% was obtained. Further improvements in energy efficiency are expected in the near future. The success of this project demonstrated the feasibility of a simulation-based approach. Currently, the Center provides simulation-based service to all the iron ore mining companies operating in northern

  12. Advancements on the simulation of the micro injection moulding process

    DEFF Research Database (Denmark)

    Marhöfer, David Maximilian; Tosello, Guido; Hansen, Hans Nørgaard

    2013-01-01

    Process simulations are applied in micro injection molding with the same purpose as in conventional injection molding: aiming at optimization and support of the design of mold, inserts, plastic products, and the process itself. Available software packages are however not well suited for micro inj...

  13. Electrical Storm Simulation to Improve the Learning Physics Process

    Science.gov (United States)

    Martínez Muñoz, Miriam; Jiménez Rodríguez, María Lourdes; Gutiérrez de Mesa, José Antonio

    2013-01-01

    This work is part of a research project whose main objective is to understand the impact that the use of Information and Communication Technology (ICT) has on the teaching and learning process on the subject of Physics. We will show that, with the use of a storm simulator, physics students improve their learning process on one hand they understand…

  14. Simulation and optimization of the cold roll-forming process

    Science.gov (United States)

    Sheu, Jinn-Jong

    2004-06-01

    In this paper, the cold roll-forming process of steel was simulated. The FEM model of rollers was built in the LS-DYNA software. There are six stands used in the cold-roll-forming process simulation. The frictions of the tools were determined by the comparison of the cold-roll-forming results and the simulation deformation. Many friction conditions were tested to approach the experimental results of the forming experiments. The blanks were pushed through the rollers in the roll-forming machine. While in the simulation, the rollers were running over the fixed-end blank instead of moving the materials. The resulted motion is the same but the boundary conditions were easier to specify and control. The rolling speeds in the simulation were higher to save the calculation time but still confirm to the experiment results. The simulation results shown the axial and the shear strains were induced during the bending process of sheet metal. The thickness of the sheet metal was varied very slightly during the roll-forming process. The dimension and shape of the cold roll-formed specimens were in good agreement with the experiment results. The Taguchi method was adopted to design an optimum roll flower.

  15. Product/Process (P/P) Models For The Defense Waste Processing Facility (DWPF): Model Ranges And Validation Ranges For Future Processing

    Energy Technology Data Exchange (ETDEWEB)

    Jantzen, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Edwards, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-09-25

    Radioactive high level waste (HLW) at the Savannah River Site (SRS) has successfully been vitrified into borosilicate glass in the Defense Waste Processing Facility (DWPF) since 1996. Vitrification requires stringent product/process (P/P) constraints since the glass cannot be reworked once it is poured into ten foot tall by two foot diameter canisters. A unique “feed forward” statistical process control (SPC) was developed for this control rather than statistical quality control (SQC). In SPC, the feed composition to the DWPF melter is controlled prior to vitrification. In SQC, the glass product would be sampled after it is vitrified. Individual glass property-composition models form the basis for the “feed forward” SPC. The models transform constraints on the melt and glass properties into constraints on the feed composition going to the melter in order to guarantee, at the 95% confidence level, that the feed will be processable and that the durability of the resulting waste form will be acceptable to a geologic repository.

  16. A General Range-Velocity Processing Scheme for Discontinuous Spectrum FMCW Signal in HFSWR Applications

    Directory of Open Access Journals (Sweden)

    Mengguan Pan

    2016-01-01

    Full Text Available Discontinuous spectrum signal which has separate subbands distributed over a wide spectrum band is a solution to synthesize a wideband waveform in a highly congested spectrum environment. In this paper, we present a general range-velocity processing scheme for the discontinuous spectrum-frequency modulated continuous wave (DS-FMCW signal specifically. In range domain, we propose a simple time rearrangement operation which converts the range transform problem of the DS-FMCW signal to a general spectral estimation problem of nonuniformly sampled data. Conventional periodogram results in a dirty range spectrum with high sidelobes which cannot be suppressed by traditional spectral weighting. In this paper, we introduce the iterative adaptive approach (IAA in the estimation of the range spectrum. IAA is shown to have the ability to provide a clean range spectrum. On the other hand, the discontinuity of the signal spectrum has little impact on the velocity processing. However, with the range resolution improved, the influence of the target motion becomes nonnegligible. We present a velocity compensation strategy which includes the intersweep compensation and in-sweep compensation. Our processing scheme with the velocity compensation is shown to provide an accurate and clean range-velocity image which benefits the following detection process.

  17. Evaluation of simulated climatological diurnal temperature range in CMIP5 models from the perspective of planetary boundary layer turbulent mixing

    Science.gov (United States)

    Wei, Nan; Zhou, Liming; Dai, Yongjiu

    2017-07-01

    This study examines the effects of modeled planetary boundary layer (PBL) mixing on the simulated temperature diurnal cycle climatology over land in 20 CMIP5 models with AMIP simulations. When compared with observations, the magnitude of diurnal temperature range (DTR) is systematically underestimated over almost all land areas due to a widespread warm bias of daily minimum temperature (Tmin) and mostly a cold bias of daily maximum temperature (Tmax). Analyses of the CMIP5 multi-model ensemble means suggest that the biases of the simulated PBL mixing could very likely contribute to the temperature biases. For the regions with the cold bias in Tmax, the daytime PBL mixing is generally underestimated. The consequent more dry air entrainment from the free atmosphere could help maintain the surface humidity gradient, and thus produce more surface evaporation and potentially lower the Tmax. The opposite situation holds true for the regions with the warm bias of Tmax. This mechanism could be particularly applicable to the regions with moderate and wet climate conditions where surface evaporation depends more on the surface humidity gradient, but less on the available soil moisture. For the widespread warm bias of Tmin, the widely-recognized overestimated PBL mixing at nighttime should play a dominant role by transferring more heat from the atmosphere to the near-surface to warm the Tmin. Further analyses using the high resolution CFMIP2 output also support the CMIP5 results about the connections of the biases between the simulated turbulent mixing and the temperature diurnal cycle. The large inter-model variations of the simulated temperature diurnal cycle primarily appear over the arid and semi-arid regions and boreal arctic regions where the model differences in the PBL turbulence mixing could make equally significant contributions to the inter-model variations of DTR, Tmax and Tmin compared to the model differences in surface radiative processes. These results

  18. 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

    1997-05-01

    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.

  19. Iterative load-balancing method with multigrid level relaxation for particle simulation with short-range interactions

    Science.gov (United States)

    Furuichi, Mikito; Nishiura, Daisuke

    2017-10-01

    We developed dynamic load-balancing algorithms for Particle Simulation Methods (PSM) involving short-range interactions, such as Smoothed Particle Hydrodynamics (SPH), Moving Particle Semi-implicit method (MPS), and Discrete Element method (DEM). These are needed to handle billions of particles modeled in large distributed-memory computer systems. Our method utilizes flexible orthogonal domain decomposition, allowing the sub-domain boundaries in the column to be different for each row. The imbalances in the execution time between parallel logical processes are treated as a nonlinear residual. Load-balancing is achieved by minimizing the residual within the framework of an iterative nonlinear solver, combined with a multigrid technique in the local smoother. Our iterative method is suitable for adjusting the sub-domain frequently by monitoring the performance of each computational process because it is computationally cheaper in terms of communication and memory costs than non-iterative methods. Numerical tests demonstrated the ability of our approach to handle workload imbalances arising from a non-uniform particle distribution, differences in particle types, or heterogeneous computer architecture which was difficult with previously proposed methods. We analyzed the parallel efficiency and scalability of our method using Earth simulator and K-computer supercomputer systems.

  20. Analysis of Using Resources in Business Process Modeling and Simulation

    Directory of Open Access Journals (Sweden)

    Vasilecas Olegas

    2014-12-01

    Full Text Available One of the key purposes of Business Process Model and Notation (BPMN is to support graphical representation of the process model. However, such models have a lack of support for the graphical representation of resources, whose processes are used during simulation or execution of process instance. The paper analyzes different methods and their extensions for resource modeling. Further, this article presents a selected set of resource properties that are relevant for resource modeling. The paper proposes an approach that explains how to use the selected set of resource properties for extension of process modeling using BPMN and simulation tools. They are based on BPMN, where business process instances use resources in a concurrency manner.

  1. A Study on the LEED Energy Simulation Process Using BIM

    Directory of Open Access Journals (Sweden)

    Han-Soo Ryu

    2016-02-01

    Full Text Available In the domestic and international environmentally friendly certification system, energy-related credit occupies a high ratio in the total distribution of certification score Leadership in the Energy and Environmental Design (LEED system is a certification system developed by the US Green Building Council (USGBC in order to assess the environmental friendliness of buildings. The energy-related credit is approximately 30% of the total and also the energy simulation ratio specifically is the highest among the single credits as it is 20%. In this research, the energy simulation process using Building Information Modeling (BIM based on the energy simulation case performed at the A-Tower, LEED certification was proposed. It places an emphasis on the verification process which was short in the previous research. The architectural geometry modeled through the BIM tool is converted to the gbXML, and in this process the geometry is verified through the interference check functions, the gbXML Viewer and the FZKViewer. The energy simulation is performed after the verification procedure. The geometry verification process in the A-Tower project is presented throughout this paper. In conclusion, an improved process is proposed for the productivity and reliability of energy simulation.

  2. SHIPBUILDING PRODUCTION PROCESS DESIGN METHODOLOGY USING COMPUTER SIMULATION

    Directory of Open Access Journals (Sweden)

    Marko Hadjina

    2015-06-01

    Full Text Available In this research a shipbuilding production process design methodology, using computer simulation, is suggested. It is expected from suggested methodology to give better and more efficient tool for complex shipbuilding production processes design procedure. Within the first part of this research existing practice for production process design in shipbuilding was discussed, its shortcomings and problem were emphasized. In continuing, discrete event simulation modelling method, as basis of suggested methodology, is investigated and described regarding its special characteristics, advantages and reasons for application, especially in shipbuilding production process. Furthermore, simulation modeling basics were described as well as suggested methodology for production process procedure. Case study of suggested methodology application for designing a robotized profile fabrication production process line is demonstrated. Selected design solution, acquired with suggested methodology was evaluated through comparison with robotized profile cutting production line installation in a specific shipyard production process. Based on obtained data from real production the simulation model was further enhanced. Finally, on grounds of this research, results and droved conclusions, directions for further research are suggested.

  3. Integration of Advanced Simulation and Visualization for Manufacturing Process Optimization

    Science.gov (United States)

    Zhou, Chenn; Wang, Jichao; Tang, Guangwu; Moreland, John; Fu, Dong; Wu, Bin

    2016-05-01

    The integration of simulation and visualization can provide a cost-effective tool for process optimization, design, scale-up and troubleshooting. The Center for Innovation through Visualization and Simulation (CIVS) at Purdue University Northwest has developed methodologies for such integration with applications in various manufacturing processes. The methodologies have proven to be useful for virtual design and virtual training to provide solutions addressing issues on energy, environment, productivity, safety, and quality in steel and other industries. In collaboration with its industrial partnerships, CIVS has provided solutions to companies, saving over US38 million. CIVS is currently working with the steel industry to establish an industry-led Steel Manufacturing Simulation and Visualization Consortium through the support of National Institute of Standards and Technology AMTech Planning Grant. The consortium focuses on supporting development and implementation of simulation and visualization technologies to advance steel manufacturing across the value chain.

  4. Age differences in simulated driving performance: compensatory processes.

    Science.gov (United States)

    Andrews, E C; Westerman, S J

    2012-03-01

    In the context of driving, the reported experiment examines compensatory processes for age-related declines in cognitive ability. Younger (26-40 years) and older (60+ years) participants (n=22 each group) performed a car following task in a driving simulator. Several performance measures were recorded, including assessments of anticipation of unfolding traffic events. Participants also completed a range of measures of cognitive ability - including both fluid and crystallised abilities. Three examples of age-related compensation are reported: (i) older drivers adopted longer headways than younger drivers. Data were consistent with this being compensation for an age-related deficit in complex reaction time; (ii) older drivers with relatively higher cognitive ability anticipated traffic events more frequently, whereas the reverse pattern was found for younger drivers; and, (iii) older drivers with greater crystallised ability were less reliant on spatial ability to maintain lane position. Consistent with theories of 'cognitive reserve', interactions between crystallised ability and age for self-report workload suggested that compensation for age-related cognitive ability deficits required investment of additional effort. Results are considered in the context of the prospects of further assessment of older drivers. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. A Thermodynamic Library for Simulation and Optimization of Dynamic Processes

    DEFF Research Database (Denmark)

    Ritschel, Tobias Kasper Skovborg; Gaspar, Jozsef; Jørgensen, John Bagterp

    2017-01-01

    compounds and mixtures. However, rigorous thermodynamic models are generally computationally intensive and not available as open-source libraries for process simulation and optimization. In this paper, we describe the application of a novel open-source rigorous thermodynamic library, ThermoLib, which....... These derivatives are needed for efficient dynamic simulation and optimization. The analytical derivatives improve the computational performance by a factor between 12 and 35 as compared to finite difference approximations. We present two examples that use ThermoLib routines in their implementations: (1) simulation...

  6. Best practice strategies for validation of micro moulding process simulation

    DEFF Research Database (Denmark)

    Costa, Franco; Tosello, Guido; Whiteside, Ben

    2009-01-01

    are the optimization of the moulding process and of the tool using simulation techniques. Therefore, in polymer micro manufacturing technology, software simulation tools adapted from conventional injection moulding can provide useful assistance for the optimization of moulding tools, mould inserts, micro component...... is challenging and therefore software validation is affected by the availability of adequately precise experimental data. In this paper, an investigation on two different micro moulded parts is presented and issues relating to the use of experimental results for the validation of micro moulding simulations...

  7. A computational method to model radar return range in a polygonally based, computer-generated-imagery simulation

    Science.gov (United States)

    Moran, F. J.; Phillips, J. D.

    1986-01-01

    Described is a method for modeling a ground-mapping radar system for use in simulations where the terrain is in a polygonal form commonly used with computer generated imagery (CGI). The method employs a unique approach for rapidly rejecting polygons not visible to the radar to facilitate the real-time simulation of the radar return. This rapid rejection of the nonvisible polygons requires the precalculation and storage of a set of parameters that do not vary during the simulation. The calculation of a radar range as a function of the radar forward-looking angle to the CGI terrain is carried out only for the visible polygons. This method was used as part of a simulation for terrain-following helicopter operations on the vertical motion simulator at the NASA Ames Research Center. It proved to be an efficient means for returning real-time simulated radar range data.

  8. Accelerating geostatistical simulations using graphics processing units (GPU)

    Science.gov (United States)

    Tahmasebi, Pejman; Sahimi, Muhammad; Mariethoz, Grégoire; Hezarkhani, Ardeshir

    2012-09-01

    Geostatistical simulations have become a widely used tool for modeling of oil and gas reservoirs and the assessment of uncertainty. One important current issue is the development of high-resolution models in a reasonable computational time. A possible solution is based on taking advantage of parallel computational strategies. In this paper we present a new methodology that exploits the benefits of graphics processing units (GPUs) along with the master-slave architecture for geostatistical simulations that are based on random paths. The methodology is a hybrid method in which different levels of master and slave processors are used to distribute the computational grid points and to maximize the use of multiple processors utilized in GPU. It avoids conflicts between concurrently simulated grid points, an important issue in high-resolution and efficient simulations. For the sake of comparison, two distinct parallelization methods are implemented, one of which is specific to pattern-based simulations. To illustrate the efficiency of the method, the algorithm for the simulation of pattern is adapted with the GPU. Performance tests are carried out with three large grid sizes. The results are compared with those obtained based on simulations with central processing units (CPU). The comparison indicates that the use of GPUs reduces the computation time by a factor of 26-85.

  9. Knowledge Based Cloud FE Simulation of Sheet Metal Forming Processes.

    Science.gov (United States)

    Zhou, Du; Yuan, Xi; Gao, Haoxiang; Wang, Ailing; Liu, Jun; El Fakir, Omer; Politis, Denis J; Wang, Liliang; Lin, Jianguo

    2016-12-13

    The use of Finite Element (FE) simulation software to adequately predict the outcome of sheet metal forming processes is crucial to enhancing the efficiency and lowering the development time of such processes, whilst reducing costs involved in trial-and-error prototyping. Recent focus on the substitution of steel components with aluminum alloy alternatives in the automotive and aerospace sectors has increased the need to simulate the forming behavior of such alloys for ever more complex component geometries. However these alloys, and in particular their high strength variants, exhibit limited formability at room temperature, and high temperature manufacturing technologies have been developed to form them. Consequently, advanced constitutive models are required to reflect the associated temperature and strain rate effects. Simulating such behavior is computationally very expensive using conventional FE simulation techniques. This paper presents a novel Knowledge Based Cloud FE (KBC-FE) simulation technique that combines advanced material and friction models with conventional FE simulations in an efficient manner thus enhancing the capability of commercial simulation software packages. The application of these methods is demonstrated through two example case studies, namely: the prediction of a material's forming limit under hot stamping conditions, and the tool life prediction under multi-cycle loading conditions.

  10. Condensation transition in a conserved generalized interacting zero-range process.

    Science.gov (United States)

    Khaleque, Abdul; Sen, Parongama

    2016-04-01

    A conserved generalized zero-range process is considered in which two sites interact such that particles hop from the more populated site to the other with a probability p. The steady-state particle distribution function P(n) is obtained using both analytical and numerical methods. The system goes through several phases as p is varied. In particular, a condensate phase appears for p_{l}condensate phase using a known scaling form shows there is universal behavior in the short-range process while the infinite range process displays nonuniversality. In the noncondensate phase above p_{c}, two distinct regions are identified: p_{c}0.5; a scale emerges in the system in the latter and this feature is present for all ranges of interaction.

  11. Numerical simulation and optimization of casting process for complex pump

    Science.gov (United States)

    Liu, Xueqin; Dong, Anping; Wang, Donghong; Lu, Yanling; Zhu, Guoliang

    2017-09-01

    The complex shape of the casting pump body has large complicated structure and uniform wall thickness, which easy give rise to casting defects. The numerical simulation software ProCAST is used to simulate the initial top gating process, after analysis of the material and structure characteristics of the high-pressure pump. The filling process was overall smooth, not there the water shortage phenomenon. But the circular shrinkage defects appear at the bottom of casting during solidification process. Then, the casting parameters were optimized and adding cold iron in the bottom. The shrinkage weight was reduced from 0.00167g to 0.0005g. The porosity volume was reduced from 1.39cm3 to 0.41cm3. The optimization scheme is simulated and actual experimented. The defect has been significantly improved.

  12. Simulation Models in Testing Reliability of Transport Process

    Directory of Open Access Journals (Sweden)

    Jacyna Marianna

    2016-07-01

    Full Text Available The paper touches the problem of applying simulation models to assess the reliability of services in transport networks. Investigation of the transport processes in terms of their reliability is a complex decision-making task. The paper describes a method for assessing the reliability of transport process on the base of the criterion of minimizing the normalized lost time of vehicles. The time is wasted in a result of conflict situations occurring in the transport network during the transport process. The study includes stochastic distributions of system input. It enables studying the quality parameters of the transport network equipment, including service providers working under different workload and all kinds of disturbances. The method uses simulation models. Simulation studies were performed with Java Modelling Tools.

  13. Simultaneous computation within a sequential process simulation tool

    Directory of Open Access Journals (Sweden)

    G. Endrestøl

    1989-10-01

    Full Text Available The paper describes an equation solver superstructure developed for a sequential modular dynamic process simulation system as part of a Eureka project with Norwegian and British participation. The purpose of the development was combining some of the advantages of equation based and purely sequential systems, enabling implicit treatment of key variables independent of module boundaries, and use of numerical integration techniques suitable for each individual type of variable. For training simulator applications the main advantages are gains in speed due to increased stability limits on time steps and improved consistency of simulation results. The system is split into an off-line analysis phase and an on-line equation solver. The off-line processing consists of automatic determination of the topological structure of the system connectivity from standard process description files and derivation of an optimized sparse matrix solution procedure for the resulting set of equations. The on-line routine collects equation coefficients from involved modules, solves the combined sets of structured equations, and stores the results appropriately. This method minimizes the processing cost during the actual simulation. The solver has been applied in the Veslefrikk training simulator project.

  14. Simulation Models of Human Decision-Making Processes

    Directory of Open Access Journals (Sweden)

    Nina RIZUN

    2014-10-01

    Full Text Available The main purpose of the paper is presentation of the new concept of human decision-making process modeling via using the analogy with Automatic Control Theory. From the author's point of view this concept allows to develop and improve the theory of decision-making in terms of the study and classification of specificity of the human intellectual processes in different conditions. It was proved that the main distinguishing feature between the Heuristic / Intuitive and Rational Decision-Making Models is the presence of so-called phenomenon of "enrichment" of the input information with human propensity, hobbies, tendencies, expectations, axioms and judgments, presumptions or bias and their justification. In order to obtain additional knowledge about the basic intellectual processes as well as the possibility of modeling the decision results in various parameters characterizing the decision-maker, the complex of the simulation models was developed. These models are based on the assumptions that:  basic intellectual processes of the Rational Decision-Making Model can be adequately simulated and identified by the transient processes of the proportional-integral-derivative controller; basic intellectual processes of the Bounded Rationality and Intuitive Models can be adequately simulated and identified by the transient processes of the nonlinear elements.The taxonomy of the most typical automatic control theory elements and their compliance with certain decision-making models with a point of view of decision-making process specificity and decision-maker behavior during a certain time of professional activity was obtained.

  15. Improving the accuracy of micro injection moulding process simulations

    DEFF Research Database (Denmark)

    Marhöfer, David Maximilian; Tosello, Guido; Islam, Aminul

    Process simulations in micro injection moulding aim at the optimization and support of the design of the mould, mould inserts, the plastic product, and the process. Nevertheless, dedicated software packages for micro injection moulding are not available. They are developed for macro plastic parts...... and are therefore limited in the capability of modelling the polymer flow in micro cavities. Hence, new strategies for comprehensive simulation models which provide more precise results open up new opportunities and will be discussed. Modelling and meshing recommendations are presented, leading to a multi...

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  17. Quantification of chemical and physical processes influencing ozone during long-range transport using a trajectory ensemble

    Directory of Open Access Journals (Sweden)

    M. Cain

    2012-08-01

    Full Text Available During long-range transport, many distinct processes – including photochemistry, deposition, emissions and mixing – contribute to the transformation of air mass composition. Partitioning the effects of different processes can be useful when considering the sensitivity of chemical transformation to, for example, a changing environment or anthropogenic influence. However, transformation is not observed directly, since mixing ratios are measured, and models must be used to relate changes to processes. Here, four cases from the ITCT-Lagrangian 2004 experiment are studied. In each case, aircraft intercepted a distinct air mass several times during transport over the North Atlantic, providing a unique dataset and quantifying the net changes in composition from all processes. A new framework is presented to deconstruct the change in O3 mixing ratio (Δ O3 into its component processes, which were not measured directly, taking into account the uncertainty in measurements, initial air mass variability and its time evolution.

    The results show that the net chemical processing (Δ O3chem over the whole simulation is greater than net physical processing (Δ O3phys in all cases. This is in part explained by cancellation effects associated with mixing. In contrast, each case is in a regime of either net photochemical destruction (lower tropospheric transport or production (an upper tropospheric biomass burning case. However, physical processes influence O3 indirectly through addition or removal of precursor gases, so that changes to physical parameters in a model can have a larger effect on Δ O3chem than Δ O3phys. Despite its smaller magnitude, the physical processing distinguishes the lower tropospheric export cases, since the net photochemical O3 change is −5 ppbv per day in all three cases.

    Processing is quantified using a Lagrangian

  18. A long range dependent model with nonlinear innovations for simulating daily river flows

    Directory of Open Access Journals (Sweden)

    P. Elek

    2004-01-01

    Full Text Available We present the analysis aimed at the estimation of flood risks of Tisza River in Hungary on the basis of daily river discharge data registered in the last 100 years. The deseasonalised series has skewed and leptokurtic distribution and various methods suggest that it possesses substantial long memory. This motivates the attempt to fit a fractional ARIMA model with non-Gaussian innovations as a first step. Synthetic streamflow series can then be generated from the bootstrapped innovations. However, there remains a significant difference between the empirical and the synthetic density functions as well as the quantiles. This brings attention to the fact that the innovations are not independent, both their squares and absolute values are autocorrelated. Furthermore, the innovations display non-seasonal periods of high and low variances. This behaviour is characteristic to generalised autoregressive conditional heteroscedastic (GARCH models. However, when innovations are simulated as GARCH processes, the quantiles and extremes of the discharge series are heavily overestimated. Therefore we suggest to fit a smooth transition GARCH-process to the innovations. In a standard GARCH model the dependence of the variance on the lagged innovation is quadratic whereas in our proposed model it is a bounded function. While preserving long memory and eliminating the correlation from both the generating noise and from its square, the new model is superior to the previously mentioned ones in approximating the probability density, the high quantiles and the extremal behaviour of the empirical river flows.

  19. Multiphase simulation of mine waters and aqueous leaching processes

    Directory of Open Access Journals (Sweden)

    Pajarre Risto

    2016-01-01

    Full Text Available Managing of large amounts of water in mining and mineral processing sites remains a concern in both actively operated and closed mining areas. When the mining site with its metal or concentrate producing units is operational, the challenge is to find either ways for economical processing with maximum yields, while minimizing the environmental impact of the water usage and waste salt treatments. For safe closure of the site, the environmental control of possible drainage will be needed. For both challenges, the present-day multiphase process simulations tools can be used to provide improved accuracy and better economy in controlling the smooth and environmentally sound operation of the plant. One of the pioneering studies in using the multiphase thermodynamic software in simulation of hydrometallurgical processes was that of Koukkari et al. [1]. The study covered the use of Solgasmix equilibrium software for a number of practical acid digesters. The models were made for sulfuric acid treatments in titania pigment production and in NPK fertilizer manufacturing. During the past two decades the extensive data assessment has taken place particularly in geochemistry and a new versions of geochemical multiphase equilibrium software has been developed. On the other hand, there has been some progress in development of the process simulation software in all the aforementioned fields. Thus, the thermodynamic simulation has become a tool of great importance in development of hydrometallurgical processes. The presentation will cover three example cases of either true pilot or industrial systems including a South African acid mine water drainage treatment, hydrometallurgical extraction of rare earths from uranium leachate in Russia and a multistage process simulation of a Finnish heap leaching mine with its subsequent water treatment system.

  20. GPU based numerical simulation of core shooting process

    Directory of Open Access Journals (Sweden)

    Yi-zhong Zhang

    2017-11-01

    Full Text Available Core shooting process is the most widely used technique to make sand cores and it plays an important role in the quality of sand cores. Although numerical simulation can hopefully optimize the core shooting process, research on numerical simulation of the core shooting process is very limited. Based on a two-fluid model (TFM and a kinetic-friction constitutive correlation, a program for 3D numerical simulation of the core shooting process has been developed and achieved good agreements with in-situ experiments. To match the needs of engineering applications, a graphics processing unit (GPU has also been used to improve the calculation efficiency. The parallel algorithm based on the Compute Unified Device Architecture (CUDA platform can significantly decrease computing time by multi-threaded GPU. In this work, the program accelerated by CUDA parallelization method was developed and the accuracy of the calculations was ensured by comparing with in-situ experimental results photographed by a high-speed camera. The design and optimization of the parallel algorithm were discussed. The simulation result of a sand core test-piece indicated the improvement of the calculation efficiency by GPU. The developed program has also been validated by in-situ experiments with a transparent core-box, a high-speed camera, and a pressure measuring system. The computing time of the parallel program was reduced by nearly 95% while the simulation result was still quite consistent with experimental data. The GPU parallelization method can successfully solve the problem of low computational efficiency of the 3D sand shooting simulation program, and thus the developed GPU program is appropriate for engineering applications.

  1. Simulation analysis of resource flexibility on healthcare processes

    Directory of Open Access Journals (Sweden)

    Simwita YW

    2016-10-01

    Full Text Available Yusta W Simwita, Berit I Helgheim Department of Logistics, Molde University College, Molde, Norway Purpose: This paper uses discrete event simulation to explore the best resource flexibility scenario and examine the effect of implementing resource flexibility on different stages of patient treatment process. Specifically we investigate the effect of resource flexibility on patient waiting time and throughput in an orthopedic care process. We further seek to explore on how implementation of resource flexibility on patient treatment processes affects patient access to healthcare services. We focus on two resources, namely, orthopedic surgeon and operating room. Methods: The observational approach was used to collect process data. The developed model was validated by comparing the simulation output with actual patient data collected from the studied orthopedic care process. We developed different scenarios to identify the best resource flexibility scenario and explore the effect of resource flexibility on patient waiting time, throughput, and future changes in demand. The developed scenarios focused on creating flexibility on service capacity of this care process by altering the amount of additional human resource capacity at different stages of patient care process and extending the use of operating room capacity.Results: The study found that resource flexibility can improve responsiveness to patient demand in the treatment process. Testing different scenarios showed that the introduction of resource flexibility reduces patient waiting time and improves throughput. The simulation results show that patient access to health services can be improved by implementing resource flexibility at different stages of the patient treatment process.Conclusion: This study contributes to the current health care literature by explaining how implementing resource flexibility at different stages of patient care processes can improve ability to respond to increasing

  2. Computer-simulated development process of Chinese characters font cognition

    Science.gov (United States)

    Chen, Jing; Mu, Zhichun; Sun, Dehui; Hu, Dunli

    2008-10-01

    The research of Chinese characters cognition is an important research aspect of cognitive science and computer science, especially artificial intelligence. In this paper, according as the traits of Chinese characters the database of Chinese characters font representations and the model of computer simulation of Chinese characters font cognition are constructed from the aspect of cognitive science. The font cognition of Chinese characters is actual a gradual process and there is the accumulation of knowledge. Through using the method of computer simulation, the development model of Chinese characters cognition was constructed. And this is the important research content of Chinese characters cognition. This model is based on self-organizing neural network and adaptive resonance theory (ART) neural network. By Combining the SOFM and ART2 network, two sets of input were trained. Through training and testing methods, the development process of Chinese characters cognition based on Chinese characters cognition was simulated. Then the results from this model and could be compared with the results that were obtained only using SOFM. By analyzing the results, this simulation suggests that the model is able to account for some empirical results. So, the model can simulate the development process of Chinese characters cognition in a way.

  3. Simulation of mould filling process for composite skeleton castings

    Directory of Open Access Journals (Sweden)

    M. Dziuba

    2008-04-01

    Full Text Available In this work authors showed selected results of simulation and experimental studies on temperature distribution during solidification of skeleton casting and mould filling process. The aim of conducted simulations was the choice of thermal and geometrical parameters for the needs of designed calculations of the skeleton castings and the estimation of the guidelines for the technology of manufacturing. The subject of numerical simulation was the analysis of ability of filling the channels of core by liquid metal at estability technological parameters.. Below the assumptions and results of the initial simulated calculations are presented. The total number of the nodes in the casting was 1920 and of the connectors was 5280 what gave filling of 100% for the nodes and 99,56% for the connectors in the results of the simulation. Together it resulted as 99,78 % of filling the volume of the casting. The nodes and connectors were filled up to the 30 level of the casting in the simulation. The all connectors were filled up to the 25 level of the casting in the simulation. Starting from the 25 level individual connectors at the side surface of the casting weren’t filled up. The connectors weren’t supplied by multi-level getting system. The differences of filling the levels are little (maximally 5 per cent.

  4. Rationalization of foundry processes on the basis of simulation experiment

    Directory of Open Access Journals (Sweden)

    S. Kukla

    2008-10-01

    Full Text Available The paper presents results of research obtained on the basis of simulation experiment, whose aim was to analyze the performance of cast iron foundry. A simulation model of automobile industry foundry was made. The course of the following processes was analyzedin a computer model: preparation of liquid cast iron, forming and filling the moulds, cooling and stamping the castings, cleaning andfinishing treatment. The sheets of multi-criterion evaluation were prepared, where criteria and variants were assessed by meansof subjective point evaluation and fuzzy character evaluation. The paper presents an analysis example of finishing activities of castings realized in foundry on traditional machines and efficient presses and in cooperation. On the basis of reports from a simulation experiment information was achieved related to activities’ duration, load of accessible resources, the problems of storage and transport, bottle necks in the system and appearing queues in from of workplaces. The research used a universal modelling and simulation packet for productionsystems - ARENA.

  5. Affine diffusions and related processes simulation, theory and applications

    CERN Document Server

    Alfonsi, Aurélien

    2015-01-01

    This book gives an overview of affine diffusions, from Ornstein-Uhlenbeck processes to Wishart processes and it considers some related diffusions such as Wright-Fisher processes. It focuses on different simulation schemes for these processes, especially second-order schemes for the weak error. It also presents some models, mostly in the field of finance, where these methods are relevant and provides some numerical experiments. The book explains the mathematical background to understand affine diffusions and analyze the accuracy of the schemes.  

  6. Hydrological and water quality processes simulation by the integrated MOHID model

    Science.gov (United States)

    Epelde, Ane; Antiguedad, Iñaki; Brito, David; Eduardo, Jauch; Neves, Ramiro; Sauvage, Sabine; Sánchez-Pérez, José Miguel

    2016-04-01

    Different modelling approaches have been used in recent decades to study the water quality degradation caused by non-point source pollution. In this study, the MOHID fully distributed and physics-based model has been employed to simulate hydrological processes and nitrogen dynamics in a nitrate vulnerable zone: the Alegria River watershed (Basque Country, Northern Spain). The results of this study indicate that the MOHID code is suitable for hydrological processes simulation at the watershed scale, as the model shows satisfactory performance at simulating the discharge (with NSE: 0.74 and 0.76 during calibration and validation periods, respectively). The agronomical component of the code, allowed the simulation of agricultural practices, which lead to adequate crop yield simulation in the model. Furthermore, the nitrogen exportation also shows satisfactory performance (with NSE: 0.64 and 0.69 during calibration and validation periods, respectively). While the lack of field measurements do not allow to evaluate the nutrient cycling processes in depth, it has been observed that the MOHID model simulates the annual denitrification according to general ranges established for agricultural watersheds (in this study, 9 kg N ha-1 year-1). In addition, the model has simulated coherently the spatial distribution of the denitrification process, which is directly linked to the simulated hydrological conditions. Thus, the model has localized the highest rates nearby the discharge zone of the aquifer and also where the aquifer thickness is low. These results evidence the strength of this model to simulate watershed scale hydrological processes as well as the crop production and the agricultural activity derived water quality degradation (considering both nutrient exportation and nutrient cycling processes).

  7. Model for Simulating a Spiral Software-Development Process

    Science.gov (United States)

    Mizell, Carolyn; Curley, Charles; Nayak, Umanath

    2010-01-01

    A discrete-event simulation model, and a computer program that implements the model, have been developed as means of analyzing a spiral software-development process. This model can be tailored to specific development environments for use by software project managers in making quantitative cases for deciding among different software-development processes, courses of action, and cost estimates. A spiral process can be contrasted with a waterfall process, which is a traditional process that consists of a sequence of activities that include analysis of requirements, design, coding, testing, and support. A spiral process is an iterative process that can be regarded as a repeating modified waterfall process. Each iteration includes assessment of risk, analysis of requirements, design, coding, testing, delivery, and evaluation. A key difference between a spiral and a waterfall process is that a spiral process can accommodate changes in requirements at each iteration, whereas in a waterfall process, requirements are considered to be fixed from the beginning and, therefore, a waterfall process is not flexible enough for some projects, especially those in which requirements are not known at the beginning or may change during development. For a given project, a spiral process may cost more and take more time than does a waterfall process, but may better satisfy a customer's expectations and needs. Models for simulating various waterfall processes have been developed previously, but until now, there have been no models for simulating spiral processes. The present spiral-process-simulating model and the software that implements it were developed by extending a discrete-event simulation process model of the IEEE 12207 Software Development Process, which was built using commercially available software known as the Process Analysis Tradeoff Tool (PATT). Typical inputs to PATT models include industry-average values of product size (expressed as number of lines of code

  8. Discrete simulation applied to the production process of electronic components

    Directory of Open Access Journals (Sweden)

    Willians dos Santos Lúcio

    2017-07-01

    Full Text Available The objective of this research is to demonstrate through simulation techniques and analyses performed in production systems of a company located in the city of Guarulhos and which produces an electronic component that has plastic, acrylic and steel, the improvements that can be applied in it with the use of a specialist software to assist in troubleshooting and help the manager in decision making. For the study, concepts of simulation, Monte Carlo method, queueing theory and the software Arena will be used. By simulating processes and evaluating performance, the software offers reports that assist the manager to see more clearly potential bottlenecks and points of improvement in process, thus effectively contributing to the company's competitiveness on the market. With the study presented in this article it will be possible to verify the importance of the use of this tool.

  9. UOE Pipe Manufacturing Process Simulation: Equipment Designing and Construction

    Science.gov (United States)

    Delistoian, Dmitri; Chirchor, Mihael

    2017-12-01

    UOE pipe manufacturing process influence directly on pipeline resilience and operation capacity. At present most spreaded pipe manufacturing method is UOE. This method is based on cold forming. After each technological step appears a certain stress and strain level. For pipe stress strain study is designed and constructed special equipment that simulate entire technological process.UOE pipe equipment is dedicated for manufacturing of longitudinally submerged arc welded DN 400 (16 inch) steel pipe.

  10. Simulation of hydrological processes in the Simiyu River, tributary of ...

    African Journals Online (AJOL)

    A spatially-distributed hydrologic model (WetSpa) is used to simulate hydrologic processes in the Simiyu River, a tributary of Lake Victoria, Tanzania. The model combines digital maps of topography, land-use and soil texture with observed daily meteorological time series to predict discharge hydrographs and spatial ...

  11. A finite volume solver for the simulation of transport processes

    NARCIS (Netherlands)

    Naifar, F.

    2006-01-01

    The simulation of the tracer transport process is an increasingly important tool to predict the distribution of pollution released in coastal waters. The equation that governs the tracer transport is the advection-diffusion equation. Thanks to the tremendous developments in computer resources and in

  12. Modeling and computational simulation of the osmotic evaporation process

    Directory of Open Access Journals (Sweden)

    Freddy Forero Longas

    2016-09-01

    Conclusions: It was found that for the conditions studied the Knudsen diffusion model is most suitable to describe the transfer of water vapor through the hydrophobic membrane. Simulations developed adequately describe the process of osmotic evaporation, becoming a tool for faster economic development of this technology.

  13. Simulation of social processes: application to social learning

    Science.gov (United States)

    Bordogna, Clelia M.; Albano, Ezequiel V.

    2003-11-01

    The teaching-learning process in a classroom context is simulated by means of the Monte Carlo method. It is found that the structure of the collaborative groups formed by the students may influence their achievements. It is shown that low-achievement students may learn at the expense of their high-achievement colleagues.

  14. Analogous simulation of nutrient transformation processes in stream ...

    African Journals Online (AJOL)

    The main transformation processes effected by the natural microbial consortium of upper Iskar River with predominant participation of sediment biofilm were simulated in the laboratory by the use of portable devices (chambers). The dynamics of real heterotrophic respiration, organic matter oxidation, denitrification and ...

  15. The 3rd colloquium on process simulation. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Jokilaakso, A. [ed.

    1996-12-31

    The presentations collected in this volume were presented at the 3rd Colloquium on Process Simulation held at Helsinki University of Technology, Espoo, Finland, June 12-14, 1996. In the more developed industrial nations, the processes for producing chemicals, energy, and materials encounter environmental concern and laws which challenge engineers to develop the processes towards more efficient, economical and safe operation. This necessitates more thorough understanding of the processes and phenomena involved. Formerly, the development of the processes was largely based on trial and error, whereas today, the development of computer performance together with the diversification of modelling software enables simulation of the processes. The increased capacity and possibilities for modelling the processes brought by the improved hardware and software, have generated a strong demand for more accurate mathematical descriptions of the processes. Especially, the coupling of computational fluid dynamics and chemical kinetics, combustion, and thermodynamics is of current interest in process oriented technology. This colloquium attempts to give examples of modelling efforts in operation in different universities, research institutes and companies. Furthermore, the aim of this colloquium is to offer an annual opportunity to the researchers to come together and discuss their common problems and the state of their investigations

  16. The 4th international colloquium on process simulation. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Jokilaakso, A. [Helsinki Univ. of Technology, Otaniemi (Finland). Dept. of Materials Science and Metallurgy

    1997-12-31

    The papers collected in this volume were presented at the 4th Colloquium on Process Simulation held at Helsinki University of Technology, Espoo, Finland, June 11-13, 1997. In the more developed industrial nations, the processes for producing chemicals, energy, and materials encounter environmental concern and laws which challenge engineers to develop the processes towards more efficient, economical and safe operation. This necessitates more thorough understanding of the processes and phenomena involved. Formerly, the development of the processes was largely based on trial and error, whereas today, the development of computer performance together with the diversification of modelling software enables simulation of the processes. The increased capacity and possibilities for modelling the processes brought by the improved hardware and software, have generated a strong demand for more accurate mathematical descriptions of the processes. Especially, the coupling of computational fluid dynamics and chemical kinetics, combustion, and thermodynamics is of current interest in process oriented technology. This colloquium attempts to give examples of modelling efforts in operation in different universities, research institutes and companies. Furthermore, the aim of this colloquium is to offer an annual opportunity to the researchers to come together and discuss their common problems and the state of their investigations

  17. Long-range nonlocality in six-point string scattering: Simulation of black hole infallers

    Science.gov (United States)

    Dodelson, Matthew; Silverstein, Eva

    2017-09-01

    We set up a tree-level six-point scattering process in which two strings are separated longitudinally such that they could only interact directly via a nonlocal spreading effect such as that predicted by light-cone gauge calculations and the Gross-Mende saddle point. One string, the "detector," is produced at a finite time with energy E by an auxiliary 2 →2 subprocess, with kinematics such that it has sufficient resolution to detect the longitudinal spreading of an additional incoming string, the "source." We test this hypothesis in a gauge-invariant S-matrix calculation convolved with an appropriate wavepacket peaked at a separation X between the central trajectories of the source and produced detector. The amplitude exhibits support for scattering at the predicted longitudinal separation X ˜α'E , in sharp contrast to the analogous quantum field theory amplitude (whose support manifestly traces out a tail of the position-space wavefunction). The effect arises in a regime in which the string amplitude is not obtained as a convergent sum of such QFT amplitudes, and has larger amplitude than similar QFT models (with the same auxiliary four-point amplitude). In a linear dilaton background, the amplitude depends on the string coupling as expected if the scattering is not simply occurring on the wavepacket tail in string theory. This manifests the scale of longitudinal spreading in a gauge-invariant S-matrix amplitude, in a calculable process with significant amplitude. It simulates a key feature of the dynamics of time-translated horizon infallers.

  18. Matrix product formula for {{U}_{q}}(A_{2}^{(1)}) -zero range process

    Science.gov (United States)

    Kuniba, Atsuo; Okado, Masato

    2017-01-01

    The {{U}q}(An(1)) -zero range processes introduced recently by Mangazeev, Maruyama and the authors are integrable discrete and continuous time Markov processes associated with the stochastic R matrix derived from the well-known {{U}q}(An(1)) quantum R matrix. By constructing a representation of the relevant Zamolodchikov-Faddeev algebra, we present, for n  =  2, a matrix product formula for the steady state probabilities in terms of q-boson operators.

  19. Improving operational anodising process performance using simulation approach

    Energy Technology Data Exchange (ETDEWEB)

    Liong, Choong-Yeun, E-mail: lg@ukm.edu.my; Ghazali, Syarah Syahidah, E-mail: syarah@gapps.kptm.edu.my [School of Mathematical Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor DE (Malaysia)

    2015-10-22

    The use of aluminium is very widespread, especially in transportation, electrical and electronics, architectural, automotive and engineering applications sectors. Therefore, the anodizing process is an important process for aluminium in order to make the aluminium durable, attractive and weather resistant. This research is focused on the anodizing process operations in manufacturing and supplying of aluminium extrusion. The data required for the development of the model is collected from the observations and interviews conducted in the study. To study the current system, the processes involved in the anodizing process are modeled by using Arena 14.5 simulation software. Those processes consist of five main processes, namely the degreasing process, the etching process, the desmut process, the anodizing process, the sealing process and 16 other processes. The results obtained were analyzed to identify the problems or bottlenecks that occurred and to propose improvement methods that can be implemented on the original model. Based on the comparisons that have been done between the improvement methods, the productivity could be increased by reallocating the workers and reducing loading time.

  20. Abdominal surgery process modeling framework for simulation using spreadsheets.

    Science.gov (United States)

    Boshkoska, Biljana Mileva; Damij, Talib; Jelenc, Franc; Damij, Nadja

    2015-08-01

    We provide a continuation of the existing Activity Table Modeling methodology with a modular spreadsheets simulation. The simulation model developed is comprised of 28 modeling elements for the abdominal surgery cycle process. The simulation of a two-week patient flow in an abdominal clinic with 75 beds demonstrates the applicability of the methodology. The simulation does not include macros, thus programming experience is not essential for replication or upgrading the model. Unlike the existing methods, the proposed solution employs a modular approach for modeling the activities that ensures better readability, the possibility of easily upgrading the model with other activities, and its easy extension and connectives with other similar models. We propose a first-in-first-served approach for simulation of servicing multiple patients. The uncertain time duration of the activities is modeled using the function "rand()". The patients movements from one activity to the next one is tracked with nested "if()" functions, thus allowing easy re-creation of the process without the need of complex programming. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  1. Smoldyn on graphics processing units: massively parallel Brownian dynamics simulations.

    Science.gov (United States)

    Dematté, Lorenzo

    2012-01-01

    Space is a very important aspect in the simulation of biochemical systems; recently, the need for simulation algorithms able to cope with space is becoming more and more compelling. Complex and detailed models of biochemical systems need to deal with the movement of single molecules and particles, taking into consideration localized fluctuations, transportation phenomena, and diffusion. A common drawback of spatial models lies in their complexity: models can become very large, and their simulation could be time consuming, especially if we want to capture the systems behavior in a reliable way using stochastic methods in conjunction with a high spatial resolution. In order to deliver the promise done by systems biology to be able to understand a system as whole, we need to scale up the size of models we are able to simulate, moving from sequential to parallel simulation algorithms. In this paper, we analyze Smoldyn, a widely diffused algorithm for stochastic simulation of chemical reactions with spatial resolution and single molecule detail, and we propose an alternative, innovative implementation that exploits the parallelism of Graphics Processing Units (GPUs). The implementation executes the most computational demanding steps (computation of diffusion, unimolecular, and bimolecular reaction, as well as the most common cases of molecule-surface interaction) on the GPU, computing them in parallel on each molecule of the system. The implementation offers good speed-ups and real time, high quality graphics output

  2. A wide-range model for simulation of pump-probe experiments with metals

    Energy Technology Data Exchange (ETDEWEB)

    Povarnitsyn, Mikhail E., E-mail: povar@ihed.ras.ru [Joint Institute for High Temperatures RAS, Izhorskaya 13 Bldg 2, Moscow, 125412 (Russian Federation); Andreev, Nikolay E. [Joint Institute for High Temperatures RAS, Izhorskaya 13 Bldg 2, Moscow, 125412 (Russian Federation); Moscow Institute of Physics and Technology (State University), Institutsky lane 9, Dolgoprudny, Moscow region, 141700 (Russian Federation); Apfelbaum, Eugeny M. [Joint Institute for High Temperatures RAS, Izhorskaya 13 Bldg 2, Moscow, 125412 (Russian Federation); Itina, Tatiana E. [Joint Institute for High Temperatures RAS, Izhorskaya 13 Bldg 2, Moscow, 125412 (Russian Federation); Laboratoire Hubert Curien, UMR CNRS 5516, 18 rue Benoit Lauras, Bat. F, 42000, St-Etienne (France); Khishchenko, Konstatntin V. [Joint Institute for High Temperatures RAS, Izhorskaya 13 Bldg 2, Moscow, 125412 (Russian Federation); Moscow Institute of Physics and Technology (State University), Institutsky lane 9, Dolgoprudny, Moscow region, 141700 (Russian Federation); Kostenko, Oleg F. [Joint Institute for High Temperatures RAS, Izhorskaya 13 Bldg 2, Moscow, 125412 (Russian Federation); Levashov, Pavel R. [Joint Institute for High Temperatures RAS, Izhorskaya 13 Bldg 2, Moscow, 125412 (Russian Federation); Moscow Institute of Physics and Technology (State University), Institutsky lane 9, Dolgoprudny, Moscow region, 141700 (Russian Federation); Veysman, Mikhail E. [Joint Institute for High Temperatures RAS, Izhorskaya 13 Bldg 2, Moscow, 125412 (Russian Federation)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Pump-probe experiments provide an integral test of the models in the theoretically difficult regime of warm dense matter. Black-Right-Pointing-Pointer The target material motion is evident for heating by femtosecond pulses of intensity more than 10{sup 14} W/cm{sup 2}. Black-Right-Pointing-Pointer Phase shift of S and P-polarized pulses is different because of separated zones of absorption. Black-Right-Pointing-Pointer Uncertainty in the pulse energy determination of {approx}10% gives substantial deflection of the theoretical curves. Black-Right-Pointing-Pointer The surface target oxide films may result in bigger phase shift in experiment. - Abstract: High precision pump-probe experiments can provide a valuable information about material states out of equilibrium. A wide-range numerical model is used for the description of material response on ultrashort laser action. The model is developed on the basis of two-temperature hydrodynamics with heat transport, ionization, plasma expansion, electron-ion collisions and two-temperature equation of state for an irradiated substance. Comparison of experimental findings with the results of simulation is used both for the numerical model verification and for calculation of plasma thermodynamic parameters that cannot be measured directly in experiment. An aluminum target is heated by an intense 400 nm (2{omega}) pump laser pulse that is incident normal to the planar target. Weak S- and P-polarized probe pulses with wavelength 800 nm (1{omega}) are used for diagnostics of the plasma. Both probe pulses illuminate the target at a 45 Degree-Sign angle. Calculation of the reflectivity and phase shift of probe pulses with both polarizations are in good agreement with experiment.

  3. Simulation of the proton implantation process in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Faccinelli, Martin; Hadley, Peter [Graz University of Technology, Institute of Solid State Physics (Austria); Jelinek, Moriz; Wuebben, Thomas [Infineon Technologies Austria AG, Villach (Austria); Laven, Johannes G.; Schulze, Hans-Joachim [Infineon Technologies AG, Neubiberg (Germany)

    2016-12-15

    Proton implantation is one of many processes used to ad-just the electronic and mechanical properties of silicon. Though the process has been extensively studied, it is still not clear which exact defects are formed and what their concentration profiles are. In this article, a simulation method is presented, which provides a better understanding of the implantation process. The simulation takes into account the diffusion of mobile point defects and their reactions to defect complexes, as well as the dissociation of defect complexes. Concentration profiles for a set of defect complexes after an implantation at 400 keV and a dose of 5 x 10{sup 14} H{sup +}cm{sup -2} are presented. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. 3D Simulation Modeling of the Tooth Wear Process.

    Directory of Open Access Journals (Sweden)

    Ning Dai

    Full Text Available Severe tooth wear is the most common non-caries dental disease, and it can seriously affect oral health. Studying the tooth wear process is time-consuming and difficult, and technological tools are frequently lacking. This paper presents a novel method of digital simulation modeling that represents a new way to study tooth wear. First, a feature extraction algorithm is used to obtain anatomical feature points of the tooth without attrition. Second, after the alignment of non-attrition areas, the initial homogeneous surface is generated by means of the RBF (Radial Basic Function implicit surface and then deformed to the final homogeneous by the contraction and bounding algorithm. Finally, the method of bilinear interpolation based on Laplacian coordinates between tooth with attrition and without attrition is used to inversely reconstruct the sequence of changes of the 3D tooth morphology during gradual tooth wear process. This method can also be used to generate a process simulation of nonlinear tooth wear by means of fitting an attrition curve to the statistical data of attrition index in a certain region. The effectiveness and efficiency of the attrition simulation algorithm are verified through experimental simulation.

  5. Void Coalescence Processes Quantified through Atomistic and Multiscale Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Rudd, R E; Seppala, E T; Dupuy, L M; Belak, J

    2005-12-31

    Simulation of ductile fracture at the atomic scale reveals many aspects of the fracture process including specific mechanisms associated with void nucleation and growth as a precursor to fracture and the plastic deformation of the material surrounding the voids and cracks. Recently we have studied void coalescence in ductile metals using large-scale atomistic and continuum simulations. Here we review that work and present some related investigations. The atomistic simulations involve three-dimensional strain-controlled multi-million atom molecular dynamics simulations of copper. The correlated growth of two voids during the coalescence process leading to fracture is investigated, both in terms of its onset and the ensuing dynamical interactions. Void interactions are quantified through the rate of reduction of the distance between the voids, through the correlated directional growth of the voids, and through correlated shape evolution of the voids. The critical inter-void ligament distance marking the onset of coalescence is shown to be approximately one void radius based on the quantification measurements used, independent of the initial separation distance between the voids and the strain-rate of the expansion of the system. No pronounced shear flow is found in the coalescence process.

  6. Microwave Processing of Simulated Advanced Nuclear Fuel Pellets

    Energy Technology Data Exchange (ETDEWEB)

    D.E. Clark; D.C. Folz

    2010-08-29

    Throughout the three-year project funded by the Department of Energy (DOE) and lead by Virginia Tech (VT), project tasks were modified by consensus to fit the changing needs of the DOE with respect to developing new inert matrix fuel processing techniques. The focus throughout the project was on the use of microwave energy to sinter fully stabilized zirconia pellets using microwave energy and to evaluate the effectiveness of techniques that were developed. Additionally, the research team was to propose fundamental concepts as to processing radioactive fuels based on the effectiveness of the microwave process in sintering the simulated matrix material.

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

    Directory of Open Access Journals (Sweden)

    P. Degenne

    2016-01-01

    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.

  8. Simulation of Stochastic Processes by Coupled ODE-PDE

    Science.gov (United States)

    Zak, Michail

    2008-01-01

    A document discusses the emergence of randomness in solutions of coupled, fully deterministic ODE-PDE (ordinary differential equations-partial differential equations) due to failure of the Lipschitz condition as a new phenomenon. It is possible to exploit the special properties of ordinary differential equations (represented by an arbitrarily chosen, dynamical system) coupled with the corresponding Liouville equations (used to describe the evolution of initial uncertainties in terms of joint probability distribution) in order to simulate stochastic processes with the proscribed probability distributions. The important advantage of the proposed approach is that the simulation does not require a random-number generator.

  9. Best practice strategies for validation of micro moulding process simulation

    DEFF Research Database (Denmark)

    Costa, Franco; Tosello, Guido; Whiteside, Ben

    2009-01-01

    be easily controlled or known by the simulation analyst and others which are not easily known. For this reason, experimental validation studies are an important tool for establishing best practice methodologies for use during analysis set up on all future design projects. During the validation studies......, detailed information about the moulding process is gathered and used to establish these methodologies. Whereas in routine design projects, these methodologies are then relied on to provide efficient but reliable working practices. Data analysis and simulations on preliminary micro-moulding experiments have...

  10. Lattice Boltzmann simulations of immiscible displacement process with large viscosity ratios

    Science.gov (United States)

    Rao, Parthib; Schaefer, Laura

    2017-11-01

    Immiscible displacement is a key physical mechanism involved in enhanced oil recovery and carbon sequestration processes. This multiphase flow phenomenon involves a complex interplay of viscous, capillary, inertial and wettability effects. The lattice Boltzmann (LB) method is an accurate and efficient technique for modeling and simulating multiphase/multicomponent flows especially in complex flow configurations and media. In this presentation we present numerical simulation results of displacement process in thin long channels. The results are based on a new psuedo-potential multicomponent LB model with multiple relaxation time collision (MRT) model and explicit forcing scheme. We demonstrate that the proposed model is capable of accurately simulating the displacement process involving fluids with a wider range of viscosity ratios (>100) and which also leads to viscosity-independent interfacial tension and reduction of some important numerical artifacts.

  11. Sparse Representation Based Range-Doppler Processing for Integrated OFDM Radar-Communication Networks

    Directory of Open Access Journals (Sweden)

    Bo Kong

    2017-01-01

    Full Text Available In an integrated radar-communication network, multiuser access techniques with minimal performance degradation and without range-Doppler ambiguities are required, especially in a dense user environment. In this paper, a multiuser access scheme with random subcarrier allocation mechanism is proposed for orthogonal frequency division multiplexing (OFDM based integrated radar-communication networks. The expression of modulation Symbol-Domain method combined with sparse representation (SR for range-Doppler estimation is introduced and a parallel reconstruction algorithm is employed. The radar target detection performance is improved with less spectrum occupation. Additionally, a Doppler frequency detector is exploited to decrease the computational complexity. Numerical simulations show that the proposed method outperforms the traditional modulation Symbol-Domain method under ideal and realistic nonideal scenarios.

  12. Phases' characteristics of poultry litter hydrothermal carbonization under a range of process parameters.

    Science.gov (United States)

    Mau, Vivian; Quance, Julie; Posmanik, Roy; Gross, Amit

    2016-11-01

    The aim of this work was to study the hydrothermal carbonization of poultry litter under a range of process parameters. Experiments were conducted to investigate the effect of HTC of poultry litter under a range of operational parameters (temperature, reaction time, and solids concentration) on the formation and characteristics of its phases. Results showed production of a hydrochar with caloric value of 24.4MJ/kg, similar to sub-bituminous coal. The gaseous phase consisted mainly of CO2. However, significant amounts of H2S dictate the need for (further) treatment. The process also produced an aqueous phase with chemical characteristics suggesting its possible use as a liquid fertilizer. Temperature had the most significant effect on processes and product formation. Solids concentration was not a significant factor once dilution effects were considered. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Cooling rate and size effects on the medium-range structure of multicomponent oxide glasses simulated by molecular dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Tilocca, Antonio [Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ (United Kingdom)

    2013-09-21

    A set of molecular dynamics simulations were performed to investigate the effect of cooling rate and system size on the medium-range structure of melt-derived multicomponent silicate glasses, represented by the quaternary 45S5 Bioglass composition. Given the significant impact of the glass degradation on applications of these materials in biomedicine and nuclear waste disposal, bulk structural features which directly affect the glass dissolution process are of particular interest. Connectivity of the silicate matrix, ion clustering and nanosegregation, distribution of ring and chain structural patterns represent critical features in this context, which can be directly extracted from the models. A key issue is represented by the effect of the computational approach on the corresponding glass models, especially in light of recent indications questioning the suitability of conventional MD approaches (that is, involving melt-and-quench of systems containing ∼10{sup 3} atoms at cooling rates of 5-10 K/ps) when applied to model these glasses. The analysis presented here compares MD models obtained with conventional and nonconventional cooling rates and system sizes, highlighting the trend and range of convergence of specific structural features in the medium range. The present results show that time-consuming computational approaches involving much lower cooling rates and/or significantly larger system sizes are in most cases not necessary in order to obtain a reliable description of the medium-range structure of multicomponent glasses. We identify the convergence range for specific properties and use them to discuss models of several glass compositions for which a possible influence of cooling-rate or size effects had been previously hypothesized. The trends highlighted here represent an important reference to obtain reliable models of multicomponent glasses and extract converged medium-range structural features which affect the glass degradation and thus their

  14. Signal processing and analysis for copper layer thickness measurement within a large variation range in the CMP process

    Science.gov (United States)

    Li, Hongkai; Zhao, Qian; Lu, Xinchun; Luo, Jianbin

    2017-11-01

    In the copper (Cu) chemical mechanical planarization (CMP) process, accurate determination of a process reaching the end point is of great importance. Based on the eddy current technology, the in situ thickness measurement of the Cu layer is feasible. Previous research studies focus on the application of the eddy current method to the metal layer thickness measurement or endpoint detection. In this paper, an in situ measurement system, which is independently developed by using the eddy current method, is applied to the actual Cu CMP process. A series of experiments are done for further analyzing the dynamic response characteristic of the output signal within different thickness variation ranges. In this study, the voltage difference of the output signal is used to represent the thickness of the Cu layer, and we can extract the voltage difference variations from the output signal fast by using the proposed data processing algorithm. The results show that the voltage difference decreases as thickness decreases in the conventional measurement range and the sensitivity increases at the same time. However, it is also found that there exists a thickness threshold, and the correlation is negative, when the thickness is more than the threshold. Furthermore, it is possible that the in situ measurement system can be used within a larger Cu layer thickness variation range by creating two calibration tables.

  15. SDSim: A Novel Simulator for Solar Drying Processes

    Directory of Open Access Journals (Sweden)

    Yolanda Bolea

    2012-01-01

    Full Text Available SDSim is a novel solar dryer simulator based in a multicrop, inclined multipass solar air heather with in-built thermal storage mathematical model. This model has been developed as a designing and developing tool used to study and forecast the behavior of the system model in order to improve its drying efficiency and achieving a return on the dryer investment. The main feature of this simulator is that most of the parameters are permitted to be changed during the simulation process allowing finding the more suitable system for any specific situation with a user-friendly environment. The model has been evaluated in a real solar dryer system by comparing model estimates to collected data.

  16. Biopharmaceutical Process Optimization with Simulation and Scheduling Tools

    Directory of Open Access Journals (Sweden)

    Demetri Petrides

    2014-09-01

    Full Text Available Design and assessment activities associated with a biopharmaceutical process are performed at different levels of detail, based on the stage of development that the product is in. Preliminary “back-of-the envelope” assessments are performed early in the development lifecycle, whereas detailed design and evaluation are performed prior to the construction of a new facility. Both the preliminary and detailed design of integrated biopharmaceutical processes can be greatly assisted by the use of process simulators, discrete event simulators or finite capacity scheduling tools. This report describes the use of such tools for bioprocess development, design, and manufacturing. The report is divided into three sections. Section One provides introductory information and explains the purpose of bioprocess simulation. Section Two focuses on the detailed modeling of a single batch bioprocess that represents the manufacturing of a therapeutic monoclonal antibody (MAb. This type of analysis is typically performed by engineers engaged in the development and optimization of such processes. Section Three focuses on production planning and scheduling models for multiproduct plants.

  17. Generic Mathematical Model for Efficient Milling Process Simulation

    Directory of Open Access Journals (Sweden)

    Hilde Perez

    2015-01-01

    Full Text Available The current challenge in metal cutting models is to estimate cutting forces in order to achieve a more accurate and efficient machining process simulation and optimization system. This paper presents an efficient mathematical model for process simulation to evaluate the cutting action with variable part geometries of helical cutters and predict the cutting forces involved in the process. The objective of this paper has been twofold: to improve both the accuracy and computational efficiency of the algorithm for cutting force estimation in peripheral milling. Runout effect and the real tool tooth trajectory are taken into account to determine the instantaneous position of the cutting flute. An expression of average chip thickness for the engaged flute in the cut is derived for cutting force calculations resulting in a more efficient process simulation method in comparison with previous models. It provides an alternative to other studies in scientific literature commonly based on numerical integration. Experiments were carried out to verify the validity of the proposed method.

  18. Numerical simulation of X90 UOE pipe forming process

    Science.gov (United States)

    Zou, Tianxia; Ren, Qiang; Peng, Yinghong; Li, Dayong; Tang, Ding; Han, Jianzeng; Li, Xinwen; Wang, Xiaoxiu

    2013-12-01

    The UOE process is an important technique to manufacture large-diameter welding pipes which are increasingly applied in oil pipelines and offshore platforms. The forming process of UOE mainly consists of five successive operations: crimping, U-forming, O-forming, welding and mechanical expansion, through which a blank is formed into a pipe in a UOE pipe mill. The blank with an appropriate edge bevel is bent into a cylindrical shape by crimping (C-forming), U-forming and O-forming successively. After the O-forming, there is an open-seam between two ends of the plate. Then, the blank is welded by automatic four-electrode submerged arc welding technique. Subsequently, the welded pipe is expanded with a mechanical expander to get a high precision circular shape. The multiple operations in the UOE mill make it difficult to control the quality of the formed pipe. Therefore, process design mainly relies on experience in practical production. In this study, the UOE forming of an API X90 pipe is studied by using finite element simulation. The mechanical properties tests are performed on the API X90 pipeline steel blank. A two-dimensional finite element model under the hypothesis of plane strain condition is developed to simulate the UOE process according to data coming from the workshop. A kinematic hardening model is used in the simulation to take the Bauschinger effect into account. The deformation characteristics of the blank during the forming processes are analyzed. The simulation results show a significant coherence in the geometric configurations comparing with the practical manufacturing.

  19. [Comparison between the Range of Movement Canine Real Cervical Spine and Numerical Simulation - Computer Model Validation].

    Science.gov (United States)

    Srnec, R; Horák, Z; Sedláček, R; Sedlinská, M; Krbec, M; Nečas, A

    2017-01-01

    PURPOSE OF THE STUDY In developing new or modifying the existing surgical treatment methods of spine conditions an integral part of ex vivo experiments is the assessment of mechanical, kinematic and dynamic properties of created constructions. The aim of the study is to create an appropriately validated numerical model of canine cervical spine in order to obtain a tool for basic research to be applied in cervical spine surgeries. For this purpose, canine is a suitable model due to the occurrence of similar cervical spine conditions in some breeds of dogs and in humans. The obtained model can also be used in research and in clinical veterinary practice. MATERIAL AND METHODS In order to create a 3D spine model, the LightSpeed 16 (GE, Milwaukee, USA) multidetector computed tomography was used to scan the cervical spine of Doberman Pinscher. The data were transmitted to Mimics 12 software (Materialise HQ, Belgium), in which the individual vertebrae were segmented on CT scans by thresholding. The vertebral geometry was exported to Rhinoceros software (McNeel North America, USA) for modelling, and subsequently the specialised software Abaqus (Dassault Systemes, France) was used to analyse the response of the physiological spine model to external load by the finite element method (FEM). All the FEM based numerical simulations were considered as nonlinear contact statistic tasks. In FEM analyses, angles between individual spinal segments were monitored in dependence on ventroflexion/ /dorziflexion. The data were validated using the latero-lateral radiographs of cervical spine of large breed dogs with no evident clinical signs of cervical spine conditions. The radiographs within the cervical spine range of motion were taken at three different positions: in neutral position, in maximal ventroflexion and in maximal dorziflexion. On X-rays, vertebral inclination angles in monitored spine positions were measured and compared with the results obtain0ed from FEM analyses of the

  20. Towards process-informed bias correction of climate change simulations

    Science.gov (United States)

    Maraun, Douglas; Shepherd, Theodore G.; Widmann, Martin; Zappa, Giuseppe; Walton, Daniel; Gutiérrez, José M.; Hagemann, Stefan; Richter, Ingo; Soares, Pedro M. M.; Hall, Alex; Mearns, Linda O.

    2017-11-01

    Biases in climate model simulations introduce biases in subsequent impact simulations. Therefore, bias correction methods are operationally used to post-process regional climate projections. However, many problems have been identified, and some researchers question the very basis of the approach. Here we demonstrate that a typical cross-validation is unable to identify improper use of bias correction. Several examples show the limited ability of bias correction to correct and to downscale variability, and demonstrate that bias correction can cause implausible climate change signals. Bias correction cannot overcome major model errors, and naive application might result in ill-informed adaptation decisions. We conclude with a list of recommendations and suggestions for future research to reduce, post-process, and cope with climate model biases.

  1. Estimation of Potential Interference Immunity of Radio Reception with Spatial Signal Processing in Mutipath Radio-Communication Channels. Part II. Meter and Decimeter Ranges

    Science.gov (United States)

    Lvov, A. V.; Metelev, S. L.

    2016-11-01

    We propose simulation models for estimating the interference immunity of radio reception using the spatial processing of signals in the airborne and ground-based communication channels of the meter and decimeter wavelength ranges. The ultimate achievable interference immunity under various radio-wave propagation conditions is studied.

  2. Simulation of the Production Process Dynamics using Vensim and Stella

    Directory of Open Access Journals (Sweden)

    Corina SBUGHEA

    2016-04-01

    Full Text Available This paper aims to make a brief presentation of the principles of dynamic systems and to analyze two applications support for modeling and simulation of the evolution of these systems. For illustration, we chose a classic model of the dynamics of the production process, which we have implemented in Vensim and Stella, in order to obtain evolutionary trajectories of the endogenous variables and analyze the behavior of the system.

  3. Visualization of Process of Wheel Steel High Ingots Simulation

    Science.gov (United States)

    Bondarenko, V. I.; Bodryaga, V. V.; Nedopekin, F. V.; Belousov, V. V.

    2017-12-01

    The mathematical model for computation of formation of wheel steel high ingots has been formulated based on the generalized system of equations consisting of the Navier-Stokes equation, the turbulent heat and mass transfer equation and the continuity equation. It is suggested to use a pattern when designing software for simulation of hydrodynamic and thermo-physical processes. A software complex with friendly input and output data flows is provided for technologists of metallurgical production.

  4. Simulated Radar Range Profiles of a Simple Room as Compound by FDTD and Xpatch

    National Research Council Canada - National Science Library

    Dogaru, Traian; Le, Calvin

    2008-01-01

    This technical report presents numerical simulations of the ultra-wideband (UWB) radar return from a simple room with a human inside, with application to sensing through the wall (STTW) radar scenarios...

  5. Manycore processing of repeated range queries over massive moving objects observations

    DEFF Research Database (Denmark)

    Lettich, Francesco; Orlando, Salvatore; Silvestri, Claudio

    2014-01-01

    . In this paper we focus on a specific data-intensive problem, concerning the repeated processing of huge amounts of range queries over massive sets of moving objects, where the spatial extents of queries and objects are continuously modified over time. To tackle this problem and significantly accelerate query......The ability to timely process significant amounts of continuously updated spatial data is mandatory for an increasing number of applications. Parallelism enables such applications to face this data-intensive challenge and allows the devised systems to feature low latency and high scalability...... processing we devise a hybrid CPU/GPU pipeline that compresses data output and save query processing work. The devised system relies on an ad-hoc spatial index leading to a problem decomposition that results in a set of independent data-parallel tasks. The index is based on a point-region quadtree space...

  6. Process simulation and parametric modeling for strategic project management

    CERN Document Server

    Morales, Peter J

    2013-01-01

    Process Simulation and Parametric Modeling for Strategic Project Management will offer CIOs, CTOs and Software Development Managers, IT Graduate Students an introduction to a set of technologies that will help them understand how to better plan software development projects, manage risk and have better insight into the complexities of the software development process.A novel methodology will be introduced that allows a software development manager to better plan and access risks in the early planning of a project.  By providing a better model for early software development estimation and softw

  7. VIRTUAL COMMISSIONING OF A ROBOTIC CELL USING TECNOMATIX PROCESS SIMULATE

    Directory of Open Access Journals (Sweden)

    Nicolae-Adrian DUMITRASCU

    2017-06-01

    Full Text Available The concept of Virtual Commissioning (VC has become one of the most essential phases in the development and simulation of automated manufacturing processes. By creating a digital copy of the real system installment, companies have the ability to test out more complex scenarios with robots and complicated mechatronics design, greatly decreasing the startup time of the plant and shortening the product’s time to the market, while increasing the overall quality at the same time. This paper presents the core concepts of VC and all the required resources and technologies that are involved in the development of a state-of-the-art manufacturing process.

  8. Simulation of sub-barrier fusion process including dynamical deformation

    Energy Technology Data Exchange (ETDEWEB)

    Hata, Kentaro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-05-01

    Four reactions ({sup 40}Ca+{sup 40}Ca, {sup 58}Ni+{sup 58}Ni, {sup 64}Ni+{sup 64}Ni and {sup 74}Ge+{sup 74}Ge) were simulated as examples of spherical nuclei, {sup 40}Ca and {sup 58}Ni and dynamical deformation, {sup 64}Ni and {sup 74}Ge. The experimental excited functions of sub-barrier fusion reaction were reproduced with high accuracy without free parameters. The sub-barrier fusion process had supposed to pass one-dimensional fusion process estimated by the principle of least action on the potential surface with a freedom of nuclear deformation. (S.Y.)

  9. Simulation of the dynamic fracture of ceramic materials based on ZrB2 in a wide temperature range

    Science.gov (United States)

    Fedorov, A. Yu.; Skripnyak, E. G.; Skripnyak, V. V.; Vaganova, I. K.

    2017-12-01

    The damage kinetics and dynamic fracture of nanostructured ZrB2-based ceramics in a wide range of temperatures were studied by the numerical simulation method. 3D models taking into account the distribution of microvoids and inclusions were used for computer simulation of deformation and fracture of ZrB2-based ceramic materials. It was shown that the dynamic fracture of ZrB2-B4C nanocomposites is quasi-brittle in a wide temperature range. The failure is caused by microcrack nucleation and coalescence. The threshold failure stresses for ZrB2-B4C nanocomposites under compression in the strain rate range 10-3-106 s-1 and temperature range from 297 to 1673 K are predicted.

  10. Line-by-line spectroscopic simulations on graphics processing units

    Science.gov (United States)

    Collange, Sylvain; Daumas, Marc; Defour, David

    2008-01-01

    We report here on software that performs line-by-line spectroscopic simulations on gases. Elaborate models (such as narrow band and correlated-K) are accurate and efficient for bands where various components are not simultaneously and significantly active. Line-by-line is probably the most accurate model in the infrared for blends of gases that contain high proportions of H 2O and CO 2 as this was the case for our prototype simulation. Our implementation on graphics processing units sustains a speedup close to 330 on computation-intensive tasks and 12 on memory intensive tasks compared to implementations on one core of high-end processors. This speedup is due to data parallelism, efficient memory access for specific patterns and some dedicated hardware operators only available in graphics processing units. It is obtained leaving most of processor resources available and it would scale linearly with the number of graphics processing units in parallel machines. Line-by-line simulation coupled with simulation of fluid dynamics was long believed to be economically intractable but our work shows that it could be done with some affordable additional resources compared to what is necessary to perform simulations on fluid dynamics alone. Program summaryProgram title: GPU4RE Catalogue identifier: ADZY_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADZY_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 62 776 No. of bytes in distributed program, including test data, etc.: 1 513 247 Distribution format: tar.gz Programming language: C++ Computer: x86 PC Operating system: Linux, Microsoft Windows. Compilation requires either gcc/g++ under Linux or Visual C++ 2003/2005 and Cygwin under Windows. It has been tested using gcc 4.1.2 under Ubuntu Linux 7.04 and using Visual C

  11. Comparing ecohydrological processes in alien vs. native ranges: perspectives from the endangered shrub Myricaria germanica

    Science.gov (United States)

    Michielon, Bruno; Campagnaro, Thomas; Porté, Annabel; Hoyle, Jo; Picco, Lorenzo; Sitzia, Tommaso

    2017-04-01

    Comparing the ecology of woody species in their alien and native ranges may provide interesting insights for theoretical ecology, invasion biology, restoration ecology and forestry. The literature which describes the biological evolution of successful plant invaders is rich and increasing. However, no general theories have been developed about the geomorphic settings which may limit or favour the alien woody species expansion along rivers. The aim of this contribution is to explore the research opportunities in the comparison of ecohydrological processes occurring in the alien vs. the native ranges of invasive tree and shrub species along the riverine corridor. We use the endangered shrub Myricaria germanica as an example. Myricaria germanica is an Euro-Asiatic pioneer species that, in the native range, develops along natural rivers, wide and dynamic. These conditions are increasingly limited by anthropogenic constraints in most European rivers. This species has been recently introduced in New Zealand, where it is spreading in some natural rivers of the Canterbury region (South Island). We present the current knowledge about the natural and anthropogenic factors influencing this species in its native range. We compare this information with the current knowledge about the same factors influencing M. germanica invasiveness and invasibility of riparian habitats in New Zealand. We stress the need to identify potential factors which could drive life-traits and growing strategies divergence which may hinder the application to the alien ranges of existing ecohydrological knowledge from native ranges. Moreover, the pattern of expansion of the alien range of species endangered in their native ranges opens new windows for research.

  12. Parallel and distributed processing in power system simulation and control

    Energy Technology Data Exchange (ETDEWEB)

    Falcao, Djalma M. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia

    1994-12-31

    Recent advances in computer technology will certainly have a great impact in the methodologies used in power system expansion and operational planning as well as in real-time control. Parallel and distributed processing are among the new technologies that present great potential for application in these areas. Parallel computers use multiple functional or processing units to speed up computation while distributed processing computer systems are collection of computers joined together by high speed communication networks having many objectives and advantages. The paper presents some ideas for the use of parallel and distributed processing in power system simulation and control. It also comments on some of the current research work in these topics and presents a summary of the work presently being developed at COPPE. (author) 53 refs., 2 figs.

  13. ATCOM: accelerated image processing for terrestrial long-range imaging through atmospheric effects

    Science.gov (United States)

    Curt, Petersen F.; Paolini, Aaron

    2013-05-01

    Long-range video surveillance performance is often severely diminished due to atmospheric turbulence. The larger apertures typically used for video-rate operation at long-range are particularly susceptible to scintillation and blurring effects that limit the overall diffraction efficiency and resolution. In this paper, we present research progress made toward a digital signal processing technique which aims to mitigate the effects of turbulence in real-time. Our previous work in this area focused on an embedded implementation for portable applications. Our more recent research has focused on functional enhancements to the same algorithm using general-purpose hardware. We present some techniques that were successfully employed to accelerate processing of high-definition color video streams and study performance under nonideal conditions involving moving objects and panning cameras. Finally, we compare the real-time performance of two implementations using a CPU and a GPU.

  14. Comparison of Multichannel Wide Dynamic Range Compression and ChannelFree Processing Strategies on Consonant Recognition.

    Science.gov (United States)

    Plyler, Patrick; Hedrick, Mark; Rinehart, Brittany; Tripp, Rebekah

    2015-01-01

    Both wide dynamic range compression (WDRC) and ChannelFree (CF) processing strategies in hearing aids were designed to improve listener comfort and consonant identification, yet few studies have actually compared them. To determine whether CF processing provides equal or better consonant identification and subjective preference than WDRC. A repeated-measures randomized design was used in which each participant identified consonants from prerecorded nonsense vowel-consonant-vowel syllables in three conditions: unaided, aided using CF processing, and aided using WDRC processing. For each of the three conditions, syllables were presented in quiet and in a speech-noise background. Participants were also asked to rate the two processing schemes according to overall preference, preference in quiet and noise, and sound quality. Twenty adults (seven females; mean age 69.7 yr) with ≥1 yr of hearing aid use participated. Ten participants had previous experience wearing aids with WDRC, and 10 had previous experience with CF processing. Participants were tested with both WDRC and CF processing. Number of consonants correct were measured and used as the dependent variable in analyses of variance with subsequent post hoc testing. For subjective preference, a listener rating form was employed with subsequent χ² analysis. Overall results showed that signal-processing strategy did not significantly affect consonant identification or subjective preference, nor did previous hearing aid use influence results. Listeners with audiometric slopes exceeding 11 dB per octave, however, preferred CF processing and performed better in noise with CF processing. CF processing is a viable alternative to WDRC for listeners with more severely sloping audiometric contours. American Academy of Audiology.

  15. CAPE-OPEN Integration for Advanced Process Engineering Co-Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Zitney, S.E.

    2006-11-01

    This paper highlights the use of the CAPE-OPEN (CO) standard interfaces in the Advanced Process Engineering Co-Simulator (APECS) developed at the National Energy Technology Laboratory (NETL). The APECS system uses the CO unit operation, thermodynamic, and reaction interfaces to provide its plug-and-play co-simulation capabilities, including the integration of process simulation with computational fluid dynamics (CFD) simulation. APECS also relies heavily on the use of a CO COM/CORBA bridge for running process/CFD co-simulations on multiple operating systems. For process optimization in the face of multiple and some time conflicting objectives, APECS offers stochastic modeling and multi-objective optimization capabilities developed to comply with the CO software standard. At NETL, system analysts are applying APECS to a wide variety of advanced power generation systems, ranging from small fuel cell systems to commercial-scale power plants including the coal-fired, gasification-based FutureGen power and hydrogen production plant.

  16. Integrated Plasma Simulation of Ion Cyclotron and Lower Hybrid Range of Frequencies Actuators in Tokamaks

    Science.gov (United States)

    Bonoli, P. T.; Shiraiwa, S.; Wright, J. C.; Harvey, R. W.; Batchelor, D. B.; Berry, L. A.; Chen, Jin; Poli, F.; Kessel, C. E.; Jardin, S. C.

    2012-10-01

    Recent upgrades to the ion cyclotron RF (ICRF) and lower hybrid RF (LHRF) components of the Integrated Plasma Simulator [1] have made it possible to simulate LH current drive in the presence of ICRF minority heating and mode conversion electron heating. The background plasma is evolved in these simulations using the TSC transport code [2]. The driven LH current density profiles are computed using advanced ray tracing (GENRAY) and Fokker Planck (CQL3D) [3] components and predictions from GENRAY/CQL3D are compared with a ``reduced'' model for LHCD (the LSC [4] code). The ICRF TORIC solver is used for minority heating with a simplified (bi-Maxwellian) model for the non-thermal ion tail. Simulation results will be presented for LHCD in the presence of ICRF heating in Alcator C-Mod. [4pt] [1] D. Batchelor et al, Journal of Physics: Conf. Series 125, 012039 (2008).[0pt] [2] S. C. Jardin et al, J. Comp. Phys. 66, 481 (1986).[0pt] [3] R. W. Harvey and M. G. McCoy, Proc. of the IAEA Tech. Comm. Meeting on Simulation and Modeling of Therm. Plasmas, Montreal, Canada (1992).[0pt] [4] D. Ignat et al, Nucl. Fus. 34, 837 (1994).[0pt] [5] M. Brambilla, Plasma Phys. and Cont. Fusion 41,1 (1999).

  17. Confidence range estimate of extended source imagery acquisition algorithms via computer simulations. [in optical communication systems

    Science.gov (United States)

    Chen, CHIEN-C.; Hui, Elliot; Okamoto, Garret

    1992-01-01

    Spatial acquisition using the sun-lit Earth as a beacon source provides several advantages over active beacon-based systems for deep-space optical communication systems. However, since the angular extend of the Earth image is large compared to the laser beam divergence, the acquisition subsystem must be capable of resolving the image to derive the proper pointing orientation. The algorithms used must be capable of deducing the receiver location given the blurring introduced by the imaging optics and the large Earth albedo fluctuation. Furthermore, because of the complexity of modelling the Earth and the tracking algorithms, an accurate estimate of the algorithm accuracy can only be made via simulation using realistic Earth images. An image simulator was constructed for this purpose, and the results of the simulation runs are reported.

  18. Construction material processed using lunar simulant in various environments

    Science.gov (United States)

    Chase, Stan; Ocallaghan-Hay, Bridget; Housman, Ralph; Kindig, Michael; King, John; Montegrande, Kevin; Norris, Raymond; Vanscotter, Ryan; Willenborg, Jonathan; Staubs, Harry

    1995-01-01

    The manufacture of construction materials from locally available resources in space is an important first step in the establishment of lunar and planetary bases. The objective of the CoMPULSIVE (Construction Material Processed Using Lunar Simulant In Various Environments) experiment is to develop a procedure to produce construction materials by sintering or melting Johnson Space Center Simulant 1 (JSC-1) lunar soil simulant in both earth-based (1-g) and microgravity (approximately 0-g) environments. The characteristics of the resultant materials will be tested to determine its physical and mechanical properties. The physical characteristics include: crystalline, thermal, and electrical properties. The mechanical properties include: compressive tensile, and flexural strengths. The simulant, placed in a sealed graphite crucible, will be heated using a high temperature furnace. The crucible will then be cooled by radiative and forced convective means. The core furnace element consists of space qualified quartz-halogen incandescent lamps with focusing mirrors. Sample temperatures of up to 2200 C are attainable using this heating method.

  19. Random Process Simulation for stochastic fatigue analysis. Ph.D. Thesis - Rice Univ., Houston, Tex.

    Science.gov (United States)

    Larsen, Curtis E.

    1988-01-01

    A simulation technique is described which directly synthesizes the extrema of a random process and is more efficient than the Gaussian simulation method. Such a technique is particularly useful in stochastic fatigue analysis because the required stress range moment E(R sup m), is a function only of the extrema of the random stress process. The family of autoregressive moving average (ARMA) models is reviewed and an autoregressive model is presented for modeling the extrema of any random process which has a unimodal power spectral density (psd). The proposed autoregressive technique is found to produce rainflow stress range moments which compare favorably with those computed by the Gaussian technique and to average 11.7 times faster than the Gaussian technique. The autoregressive technique is also adapted for processes having bimodal psd's. The adaptation involves using two autoregressive processes to simulate the extrema due to each mode and the superposition of these two extrema sequences. The proposed autoregressive superposition technique is 9 to 13 times faster than the Gaussian technique and produces comparable values for E(R sup m) for bimodal psd's having the frequency of one mode at least 2.5 times that of the other mode.

  20. Simulation of anaerobic digestion processes using stochastic algorithm.

    Science.gov (United States)

    Palanichamy, Jegathambal; Palani, Sundarambal

    2014-01-01

    The Anaerobic Digestion (AD) processes involve numerous complex biological and chemical reactions occurring simultaneously. Appropriate and efficient models are to be developed for simulation of anaerobic digestion systems. Although several models have been developed, mostly they suffer from lack of knowledge on constants, complexity and weak generalization. The basis of the deterministic approach for modelling the physico and bio-chemical reactions occurring in the AD system is the law of mass action, which gives the simple relationship between the reaction rates and the species concentrations. The assumptions made in the deterministic models are not hold true for the reactions involving chemical species of low concentration. The stochastic behaviour of the physicochemical processes can be modeled at mesoscopic level by application of the stochastic algorithms. In this paper a stochastic algorithm (Gillespie Tau Leap Method) developed in MATLAB was applied to predict the concentration of glucose, acids and methane formation at different time intervals. By this the performance of the digester system can be controlled. The processes given by ADM1 (Anaerobic Digestion Model 1) were taken for verification of the model. The proposed model was verified by comparing the results of Gillespie's algorithms with the deterministic solution for conversion of glucose into methane through degraders. At higher value of 'τ' (timestep), the computational time required for reaching the steady state is more since the number of chosen reactions is less. When the simulation time step is reduced, the results are similar to ODE solver. It was concluded that the stochastic algorithm is a suitable approach for the simulation of complex anaerobic digestion processes. The accuracy of the results depends on the optimum selection of tau value.

  1. Measurement and simulation of thermistor response time in the millisecond range

    Science.gov (United States)

    Balko, Bohdan; Berger, Robert L.; Anderson, Karen

    1981-06-01

    The Finite Element Simulation Technique (FEST) has been applied to the design of hermetically-sealed thermistors with millisecond response times. These thermistors are used in stopped-flow calorimeters developed especially for investigations of biological reactions. FEST is also used to reconstruct the reaction kinetics obtained with these thermistors by correcting for their finite sensor response times and temperature loss.

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

    Directory of Open Access Journals (Sweden)

    Nathan Huynh

    2012-01-01

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

  3. Holistic simulation of geotechnical installation processes numerical and physical modelling

    CERN Document Server

    2015-01-01

    The book provides suitable methods for the simulations of boundary value problems of geotechnical installation processes with reliable prediction for the deformation behavior of structures in static or dynamic interaction with the soil. It summarizes the basic research of a research group from scientists dealing with constitutive relations of soils and their implementations as well as contact element formulations in FE-codes. Numerical and physical experiments are presented providing benchmarks for future developments in this field. Boundary value problems have been formulated and solved with the developed tools in order to show the effectivity of the methods. Parametric studies of geotechnical installation processes in order to identify the governing parameters for the optimization of the process are given in such a way that the findings can be recommended to practice for further use. For many design engineers in practice the assessment of the serviceability of nearby structures due to geotechnical installat...

  4. Advanced Wear Simulation for Bulk Metal Forming Processes

    Directory of Open Access Journals (Sweden)

    Behrens Bernd-Arno

    2016-01-01

    Full Text Available In the recent decades the finite element method has become an essential tool for the cost-efficient virtual process design in the metal forming sector in order to counter the constantly increasing quality standards, particularly from the automotive industry as well as intensified international competition in the forging industry. An optimized process design taking precise tool wear prediction into account is a way to increase the cost-efficiency of the bulk metal forming processes. The main objective of the work presented in this paper is a modelling algorithm, which allows predicting die wear with respect to a geometry update during the forming simulation. Changes in the contact area caused by geometry update lead to the different die wear distribution. It primarily concerns the die areas, which undergo high thermal and mechanical loads.

  5. IMPROVEMENT OF SLAB REHEATING PROCESS AT USIMINAS THROUGH MATHEMATICAL SIMULATION

    Directory of Open Access Journals (Sweden)

    Antônio Adel dos Santos

    2012-09-01

    Full Text Available Basic characteristics and application examples of the mathematical simulator for reheating process in walking-beam type furnaces, that has been developed and applied to Usiminas plate mill line at Ipatinga, are shown in this paper. This is a bi-dimensional mathematical model solved by the finite volume method, validated by temperature measurements inside the slab during heating and coded as a visual tool. Among these applications, the following can be highlighted: (i determination of suitable furnace zone temperatures and residence times for processing steels by accelerated cooling technology; (ii determination of slab average temperature at discharging as well as at each zone exit, supplying data to be fed to the automation system at the comissioning stage; (iii analyses of slab thermal distribution through the reheating process, enabling operational optimization

  6. Three-dimensional numerical simulation during laser processing of CFRP

    Science.gov (United States)

    Ohkubo, Tomomasa; Sato, Yuji; Matsunaga, Ei-ichi; Tsukamoto, Masahiro

    2017-09-01

    We performed three-dimensional numerical simulation about laser processing of carbon-fiber-reinforced plastic (CFRP) using OpenFOAM as libraries of finite volume method (FVM). Although a little theoretical or numerical studies about heat affected zone (HAZ) formation were performed, there is no research discussing how HAZ is generated considering time development about removal of each material. It is important to understand difference of removal speed of carbon fiber and resin in order to improve quality of cut surface of CFRP. We demonstrated how the carbon fiber and resin are removed by heat of ablation plume by our simulation. We found that carbon fiber is removed faster than resin at first stage because of the difference of thermal conductivity, and after that, the resin is removed faster because of its low combustion temperature. This result suggests the existence of optimal contacting time of the laser ablation and kerf of the target.

  7. Simulation and analysis of conjunctive use with MODFLOW's farm process

    Science.gov (United States)

    Hanson, R.T.; Schmid, W.; Faunt, C.C.; Lockwood, B.

    2010-01-01

    The extension of MODFLOW onto the landscape with the Farm Process (MF-FMP) facilitates fully coupled simulation of the use and movement of water from precipitation, streamflow and runoff, groundwater flow, and consumption by natural and agricultural vegetation throughout the hydrologic system at all times. This allows for more complete analysis of conjunctive use water-resource systems than previously possible with MODFLOW by combining relevant aspects of the landscape with the groundwater and surface water components. This analysis is accomplished using distributed cell-by-cell supply-constrained and demand-driven components across the landscape within " water-balance subregions" comprised of one or more model cells that can represent a single farm, a group of farms, or other hydrologic or geopolitical entities. Simulation of micro-agriculture in the Pajaro Valley and macro-agriculture in the Central Valley are used to demonstrate the utility of MF-FMP. For Pajaro Valley, the simulation of an aquifer storage and recovery system and related coastal water distribution system to supplant coastal pumpage was analyzed subject to climate variations and additional supplemental sources such as local runoff. For the Central Valley, analysis of conjunctive use from different hydrologic settings of northern and southern subregions shows how and when precipitation, surface water, and groundwater are important to conjunctive use. The examples show that through MF-FMP's ability to simulate natural and anthropogenic components of the hydrologic cycle, the distribution and dynamics of supply and demand can be analyzed, understood, and managed. This analysis of conjunctive use would be difficult without embedding them in the simulation and are difficult to estimate a priori. Journal compilation ?? 2010 National Ground Water Association. No claim to original US government works.

  8. Accelerating Cardiac Bidomain Simulations Using Graphics Processing Units

    Science.gov (United States)

    Neic, Aurel; Liebmann, Manfred; Hoetzl, Elena; Mitchell, Lawrence; Vigmond, Edward J.; Haase, Gundolf

    2013-01-01

    Anatomically realistic and biophysically detailed multiscale computer models of the heart are playing an increasingly important role in advancing our understanding of integrated cardiac function in health and disease. Such detailed simulations, however, are computationally vastly demanding, which is a limiting factor for a wider adoption of in-silico modeling. While current trends in high-performance computing (HPC) hardware promise to alleviate this problem, exploiting the potential of such architectures remains challenging since strongly scalable algorithms are necessitated to reduce execution times. Alternatively, acceleration technologies such as graphics processing units (GPUs) are being considered. While the potential of GPUs has been demonstrated in various applications, benefits in the context of bidomain simulations where large sparse linear systems have to be solved in parallel with advanced numerical techniques are less clear. In this study, the feasibility of multi-GPU bidomain simulations is demonstrated by running strong scalability benchmarks using a state-of-the-art model of rabbit ventricles. The model is spatially discretized using the finite element methods (FEM) on fully unstructured grids. The GPU code is directly derived from a large pre-existing code, the Cardiac Arrhythmia Research Package (CARP), with very minor perturbation of the code base. Overall, bidomain simulations were sped up by a factor of 11.8 to 16.3 in benchmarks running on 6–20 GPUs compared to the same number of CPU cores. To match the fastest GPU simulation which engaged 20GPUs, 476 CPU cores were required on a national supercomputing facility. PMID:22692867

  9. Molecular dynamics simulation of gas models of Lennard-Jones type interactions: Extensivity associated with interaction range and external noise

    Science.gov (United States)

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

    2017-06-01

    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.

  10. The Ansel Adams zone system: HDR capture and range compression by chemical processing

    Science.gov (United States)

    McCann, John J.

    2010-02-01

    We tend to think of digital imaging and the tools of PhotoshopTM as a new phenomenon in imaging. We are also familiar with multiple-exposure HDR techniques intended to capture a wider range of scene information, than conventional film photography. We know about tone-scale adjustments to make better pictures. We tend to think of everyday, consumer, silver-halide photography as a fixed window of scene capture with a limited, standard range of response. This description of photography is certainly true, between 1950 and 2000, for instant films and negatives processed at the drugstore. These systems had fixed dynamic range and fixed tone-scale response to light. All pixels in the film have the same response to light, so the same light exposure from different pixels was rendered as the same film density. Ansel Adams, along with Fred Archer, formulated the Zone System, staring in 1940. It was earlier than the trillions of consumer photos in the second half of the 20th century, yet it was much more sophisticated than today's digital techniques. This talk will describe the chemical mechanisms of the zone system in the parlance of digital image processing. It will describe the Zone System's chemical techniques for image synthesis. It also discusses dodging and burning techniques to fit the HDR scene into the LDR print. Although current HDR imaging shares some of the Zone System's achievements, it usually does not achieve all of them.

  11. Cyclotron resonant scattering feature simulations. II. Description of the CRSF simulation process

    Science.gov (United States)

    Schwarm, F.-W.; Ballhausen, R.; Falkner, S.; Schönherr, G.; Pottschmidt, K.; Wolff, M. T.; Becker, P. A.; Fürst, F.; Marcu-Cheatham, D. M.; Hemphill, P. B.; Sokolova-Lapa, E.; Dauser, T.; Klochkov, D.; Ferrigno, C.; Wilms, J.

    2017-05-01

    Context. Cyclotron resonant scattering features (CRSFs) are formed by scattering of X-ray photons off quantized plasma electrons in the strong magnetic field (of the order 1012 G) close to the surface of an accreting X-ray pulsar. Due to the complex scattering cross-sections, the line profiles of CRSFs cannot be described by an analytic expression. Numerical methods, such as Monte Carlo (MC) simulations of the scattering processes, are required in order to predict precise line shapes for a given physical setup, which can be compared to observations to gain information about the underlying physics in these systems. Aims: A versatile simulation code is needed for the generation of synthetic cyclotron lines. Sophisticated geometries should be investigatable by making their simulation possible for the first time. Methods: The simulation utilizes the mean free path tables described in the first paper of this series for the fast interpolation of propagation lengths. The code is parallelized to make the very time-consuming simulations possible on convenient time scales. Furthermore, it can generate responses to monoenergetic photon injections, producing Green's functions, which can be used later to generate spectra for arbitrary continua. Results: We develop a new simulation code to generate synthetic cyclotron lines for complex scenarios, allowing for unprecedented physical interpretation of the observed data. An associated XSPEC model implementation is used to fit synthetic line profiles to NuSTAR data of Cep X-4. The code has been developed with the main goal of overcoming previous geometrical constraints in MC simulations of CRSFs. By applying this code also to more simple, classic geometries used in previous works, we furthermore address issues of code verification and cross-comparison of various models. The XSPEC model and the Green's function tables are available online (see link in footnote, page 1).

  12. Simulation of Powder Layer Deposition in Additive Manufacturing Processes Using the Discrete Element Method

    Energy Technology Data Exchange (ETDEWEB)

    Herbold, E. B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Walton, O. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Homel, M. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-26

    This document serves as a final report to a small effort where several improvements were added to a LLNL code GEODYN-­L to develop Discrete Element Method (DEM) algorithms coupled to Lagrangian Finite Element (FE) solvers to investigate powder-­bed formation problems for additive manufacturing. The results from these simulations will be assessed for inclusion as the initial conditions for Direct Metal Laser Sintering (DMLS) simulations performed with ALE3D. The algorithms were written and performed on parallel computing platforms at LLNL. The total funding level was 3-­4 weeks of an FTE split amongst two staff scientists and one post-­doc. The DEM simulations emulated, as much as was feasible, the physical process of depositing a new layer of powder over a bed of existing powder. The DEM simulations utilized truncated size distributions spanning realistic size ranges with a size distribution profile consistent with realistic sample set. A minimum simulation sample size on the order of 40-­particles square by 10-­particles deep was utilized in these scoping studies in order to evaluate the potential effects of size segregation variation with distance displaced in front of a screed blade. A reasonable method for evaluating the problem was developed and validated. Several simulations were performed to show the viability of the approach. Future investigations will focus on running various simulations investigating powder particle sizing and screen geometries.

  13. Autonomous agent-based simulation of a model simulating the human air-threat assessment process

    OpenAIRE

    Ozkan, Baris Egemen

    2004-01-01

    Approved for public release; distribution is unlimited The Air Defense Laboratory (ADL) Simulation is a software program that models the way an air-defense officer thinks in the threat assessment process. The model uses multi-agent system (MAS) technology and is implemented in Java programming language. This research is a portion of Red Intent Project whose goal is to ultimately implement a model to predict the intent of any given track in the environment. For any air track in the simulati...

  14. SU-F-T-184: 3D Range-Modulator for Scanned Particle Therapy: Development, Monte Carlo Simulations and Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Simeonov, Y; Penchev, P; Ringbaek, T Printz [University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen (Germany); Brons, S [Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg (Germany); Weber, U [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Zink, K [University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen (Germany); University Hospital Giessen-Marburg, Marburg (Germany)

    2016-06-15

    Purpose: Active raster scanning in particle therapy results in highly conformal dose distributions. Treatment time, however, is relatively high due to the large number of different iso-energy layers used. By using only one energy and the so called 3D range-modulator irradiation times of a few seconds only can be achieved, thus making delivery of homogeneous dose to moving targets (e.g. lung cancer) more reliable. Methods: A 3D range-modulator consisting of many pins with base area of 2.25 mm2 and different lengths was developed and manufactured with rapid prototyping technique. The form of the 3D range-modulator was optimised for a spherical target volume with 5 cm diameter placed at 25 cm in a water phantom. Monte Carlo simulations using the FLUKA package were carried out to evaluate the modulating effect of the 3D range-modulator and simulate the resulting dose distribution. The fine and complicated contour form of the 3D range-modulator was taken into account by a specially programmed user routine. Additionally FLUKA was extended with the capability of intensity modulated scanning. To verify the simulation results dose measurements were carried out at the Heidelberg Ion Therapy Center (HIT) with a 400.41 MeV 12C beam. Results: The high resolution measurements show that the 3D range-modulator is capable of producing homogeneous 3D conformal dose distributions, simultaneously reducing significantly irradiation time. Measured dose is in very good agreement with the previously conducted FLUKA simulations, where slight differences were traced back to minor manufacturing deviations from the perfect optimised form. Conclusion: Combined with the advantages of very short treatment time the 3D range-modulator could be an alternative to treat small to medium sized tumours (e.g. lung metastasis) with the same conformity as full raster-scanning treatment. Further simulations and measurements of more complex cases will be conducted to investigate the full potential of the 3D

  15. Current loops and fluctuations in the zero-range process on a diamond lattice

    Science.gov (United States)

    Villavicencio-Sanchez, R.; Harris, R. J.; Touchette, H.

    2012-07-01

    We study the zero-range process on a simple diamond lattice with open boundary conditions and determine the conditions for the existence of loops in the mean current. We also perform a large deviation analysis for fluctuations of partial and total currents and check the validity of the Gallavotti-Cohen fluctuation relation for these quantities. In this context, we show that the fluctuation relation is not satisfied for partial currents between sites even if it is satisfied for the total current flowing between the boundaries. Finally, we extend our methods to study a chain of coupled diamonds and demonstrate co-existence of mean current regimes.

  16. Density and current profiles in Uq (A2(1)) zero range process

    Science.gov (United States)

    Kuniba, A.; Mangazeev, V. V.

    2017-09-01

    The stochastic R matrix for Uq (An(1)) introduced recently gives rise to an integrable zero range process of n classes of particles in one dimension. For n = 2 we investigate how finitely many first class particles fixed as defects influence the grand canonical ensemble of the second class particles. By using the matrix product stationary probabilities involving infinite products of q-bosons, exact formulas are derived for the local density and current of the second class particles in the large volume limit.

  17. Validation of full-wave simulations for mode conversion of waves in the ion cyclotron range of frequencies with phase contrast imaging in Alcator C-Mod

    Science.gov (United States)

    Tsujii, N.; Porkolab, M.; Bonoli, P. T.; Edlund, E. M.; Ennever, P. C.; Lin, Y.; Wright, J. C.; Wukitch, S. J.; Jaeger, E. F.; Green, D. L.; Harvey, R. W.

    2015-08-01

    Mode conversion of fast waves in the ion cyclotron range of frequencies (ICRF) is known to result in current drive and flow drive under optimised conditions, which may be utilized to control plasma profiles and improve fusion plasma performance. To describe these processes accurately in a realistic toroidal geometry, numerical simulations are essential. Quantitative comparison of these simulations and the actual experimental measurements is important to validate their predictions and to evaluate their limitations. The phase contrast imaging (PCI) diagnostic has been used to directly detect the ICRF waves in the Alcator C-Mod tokamak. The measurements have been compared with full-wave simulations through a synthetic diagnostic technique. Recently, the frequency response of the PCI detector array on Alcator C-Mod was recalibrated, which greatly improved the comparison between the measurements and the simulations. In this study, mode converted waves for D-3He and D-H plasmas with various ion species compositions were re-analyzed with the new calibration. For the minority heating cases, self-consistent electric fields and a minority ion distribution function were simulated by iterating a full-wave code and a Fokker-Planck code. The simulated mode converted wave intensity was in quite reasonable agreement with the measurements close to the antenna, but discrepancies remain for comparison at larger distances.

  18. Validation of full-wave simulations for mode conversion of waves in the ion cyclotron range of frequencies with phase contrast imaging in Alcator C-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Tsujii, N., E-mail: tsujii@k.u-tokyo.ac.jp [Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8561 (Japan); Porkolab, M.; Bonoli, P. T.; Edlund, E. M.; Ennever, P. C.; Lin, Y.; Wright, J. C.; Wukitch, S. J. [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Jaeger, E. F. [XCEL Engineering, Inc., Oak Ridge, Tennessee 37830 (United States); Green, D. L. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Harvey, R. W. [CompX, Del Mar, California 92014 (United States)

    2015-08-15

    Mode conversion of fast waves in the ion cyclotron range of frequencies (ICRF) is known to result in current drive and flow drive under optimised conditions, which may be utilized to control plasma profiles and improve fusion plasma performance. To describe these processes accurately in a realistic toroidal geometry, numerical simulations are essential. Quantitative comparison of these simulations and the actual experimental measurements is important to validate their predictions and to evaluate their limitations. The phase contrast imaging (PCI) diagnostic has been used to directly detect the ICRF waves in the Alcator C-Mod tokamak. The measurements have been compared with full-wave simulations through a synthetic diagnostic technique. Recently, the frequency response of the PCI detector array on Alcator C-Mod was recalibrated, which greatly improved the comparison between the measurements and the simulations. In this study, mode converted waves for D-{sup 3}He and D-H plasmas with various ion species compositions were re-analyzed with the new calibration. For the minority heating cases, self-consistent electric fields and a minority ion distribution function were simulated by iterating a full-wave code and a Fokker-Planck code. The simulated mode converted wave intensity was in quite reasonable agreement with the measurements close to the antenna, but discrepancies remain for comparison at larger distances.

  19. Direct numerical simulation of microcavitation processes in different bio environments

    Science.gov (United States)

    Ly, Kevin; Wen, Sy-Bor; Schmidt, Morgan S.; Thomas, Robert J.

    2017-02-01

    Laser-induced microcavitation refers to the rapid formation and expansion of a vapor bubble inside the bio-tissue when it is exposed to intense, pulsed laser energy. With the associated microscale dissection occurring within the tissue, laserinduced microcavitation is a common approach for high precision bio-surgeries. For example, laser-induced microcavitation is used for laser in-situ keratomileusis (LASIK) to precisely reshape the midstromal corneal tissue through excimer laser beam. Multiple efforts over the last several years have observed unique characteristics of microcavitions in biotissues. For example, it was found that the threshold energy for microcavitation can be significantly reduced when the size of the biostructure is increased. Also, it was found that the dynamics of microcavitation are significantly affected by the elastic modules of the bio-tissue. However, these efforts have not focused on the early events during microcavitation development. In this study, a direct numerical simulation of the microcavitation process based on equation of state of the biotissue was established. With the direct numerical simulation, we were able to reproduce the dynamics of microcavitation in water-rich bio tissues. Additionally, an experimental setup in deionized water and 10% PAA gel was made to verify the results of the simulation for early micro-cavitation formation for 10% Polyacrylamide (PAA) gel in deionized water.

  20. Simulation of the Burridge-Knopoff Model of Earthquakes with Variable Range Stress Transfer

    Science.gov (United States)

    Xia, Junchao; Gould, Harvey; Klein, W.; Rundle, J. B.

    2005-12-01

    Simple models of earthquake faults are important for understanding the mechanisms for their observed behavior, such as Gutenberg-Richter scaling and the relation between large and small events, which is the basis for various forecasting methods. Although cellular automaton models have been studied extensively in the long-range stress transfer limit, this limit has not been studied for the Burridge-Knopoff model, which includes more realistic friction forces and inertia. We find that the latter model with long-range stress transfer exhibits qualitatively different behavior than both the long-range cellular automaton models and the usual Burridge-Knopoff model with nearest-neighbor springs, depending on the nature of the velocity-weakening friction force. These results have important implications for our understanding of earthquakes and other driven dissipative systems.

  1. 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

    2011-01-01

    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.

  2. Design space development for the extraction process of Danhong injection using a Monte Carlo simulation method.

    Science.gov (United States)

    Gong, Xingchu; Li, Yao; Chen, Huali; Qu, Haibin

    2015-01-01

    A design space approach was applied to optimize the extraction process of Danhong injection. Dry matter yield and the yields of five active ingredients were selected as process critical quality attributes (CQAs). Extraction number, extraction time, and the mass ratio of water and material (W/M ratio) were selected as critical process parameters (CPPs). Quadratic models between CPPs and CQAs were developed with determination coefficients higher than 0.94. Active ingredient yields and dry matter yield increased as the extraction number increased. Monte-Carlo simulation with models established using a stepwise regression method was applied to calculate the probability-based design space. Step length showed little effect on the calculation results. Higher simulation number led to results with lower dispersion. Data generated in a Monte Carlo simulation following a normal distribution led to a design space with a smaller size. An optimized calculation condition was obtained with 10,000 simulation times, 0.01 calculation step length, a significance level value of 0.35 for adding or removing terms in a stepwise regression, and a normal distribution for data generation. The design space with a probability higher than 0.95 to attain the CQA criteria was calculated and verified successfully. Normal operating ranges of 8.2-10 g/g of W/M ratio, 1.25-1.63 h of extraction time, and two extractions were recommended. The optimized calculation conditions can conveniently be used in design space development for other pharmaceutical processes.

  3. Computer simulation of an industrial wastewater treatment process

    Energy Technology Data Exchange (ETDEWEB)

    Jenke, D.R.; Diebold, F.E.

    1985-01-01

    The computer program REDEQL.EPAK has been modified to allow for the prediction and simulation of the chemical effects of mixing 2 or more aqueous solutions and one or more solid phases. In this form the program is capable of modelling the lime neutralisation treatment process for acid mine waters. The program calculates the speciation of all influent solutions, evaluates the equilibrium composition of any mixed solution and provides the stoichiometry of the liquid and solid phases produced as a result of the mixing. The program is used to predict the optimum treatment effluent composition, to determine the amount of neutralising agent (lime) required to produce this optimum composition and to provide information which defines the mechanism controlling the treatment process.

  4. A simulation study of the critical ionization velocity process

    Science.gov (United States)

    Machida, S.; Goertz, C. K.

    1986-01-01

    The critical ionization velocity process is studied by first investigating a coupled system of equations describing the production of several ion species and electrons by impact ionization, their collisions with neutrals, and the heating of electrons. Analytic relations derived from this were tested with the help of a particle simulation, including collisional processes between neutrals and plasma particles. It was found that resistive heating of electrons plays an important role when the density of the neutrals is high, and that electron heating due to lower hybrid waves is significant when the neutral density is low. In both cases, the control of the plasma production rate by the ratio of the beam velocity to the critical velocity was verified.

  5. [Innovation in healthcare processes and patient safety using clinical simulation].

    Science.gov (United States)

    Rojo, E; Maestre, J M; Díaz-Mendi, A R; Ansorena, L; Del Moral, I

    2016-01-01

    Many excellent ideas are never implemented or generalised by healthcare organisations. There are two related paradigms: thinking that individuals primarily change through accumulating knowledge, and believing that the dissemination of that knowledge within the organisation is the key element to facilitate change. As an alternative, a description and evaluation of a simulation-based inter-professional team training program conducted in a Regional Health Service to promote and facilitate change is presented. The Department of Continuing Education completed the needs assessment using the proposals presented by clinical units and management. Skills and behaviors that could be learned using simulation were selected, and all personnel from the units participating were included. Experiential learning principles based on clinical simulation and debriefing, were used for the instructional design. The Kirkpatrick model was used to evaluate the program. Objectives included: a) decision-making and teamwork skills training in high prevalence diseases with a high rate of preventable complications; b) care processes reorganisation to improve efficiency, while maintaining patient safety; and, c) implementation of new complex techniques with a long learning curve, and high preventable complications rate. Thirty clinical units organised 39 training programs in the 3 public hospitals, and primary care of the Regional Health Service during 2013-2014. Over 1,559 healthcare professionals participated, including nursing assistants, nurses and physicians. Simulation in healthcare to train inter-professional teams can promote and facilitate change in patient care, and organisational re-engineering. Copyright © 2016 SECA. Publicado por Elsevier España, S.L.U. All rights reserved.

  6. Historical range of variability in live and dead wood biomass: a regional-scale simulation study

    Science.gov (United States)

    Etsuko Nonaka; Thomas A. Spies; Michael C. Wimberly; Janet L. Ohmann

    2007-01-01

    The historical range of variability (HRV) in landscape structure and composition created by natural disturbance can serve as a general guide for evaluating ecological conditions of managed landscapes. HRV approaches to evaluating landscapes have been based on age classes or developmental stages, which may obscure variation in live and dead stand structure. Developing...

  7. Persistence of pathogenic prion protein during simulated wastewater treatment processes

    Science.gov (United States)

    Hinckley, G.T.; Johnson, C.J.; Jacobson, K.H.; Bartholomay, C.; Mcmahon, K.D.; McKenzie, D.; Aiken, Judd M.; Pedersen, J.A.

    2008-01-01

    Transmissible spongiform encephalopathies (TSEs, prion diseases) are a class of fatal neurodegenerative diseases affecting a variety of mammalian species including humans. A misfolded form of the prion protein (PrP TSE) is the major, if not sole, component of the infectious agent. Prions are highly resistant to degradation and to many disinfection procedures suggesting that, if prions enter wastewater treatment systems through sewers and/or septic systems (e.g., from slaughterhouses, necropsy laboratories, rural meat processors, private game dressing) or through leachate from landfills that have received TSE-contaminated material, prions could survive conventional wastewater treatment Here, we report the results of experiments examining the partitioning and persistence of PrPTSE during simulated wastewater treatment processes including activated and mesophilic anaerobic sludge digestion. Incubation with activated sludge did not result in significant PrPTSE degradation. PrPTSE and prion infectivity partitioned strongly to activated sludge solids and are expected to enter biosolids treatment processes. A large fraction of PrPTSE survived simulated mesophilic anaerobic sludge digestion. The small reduction in recoverable PrPTSE after 20-d anaerobic sludge digestion appeared attributable to a combination of declining extractability with time and microbial degradation. Our results suggest that if prions were to enter municipal wastewater treatment systems, most would partition to activated sludge solids, survive mesophilic anaerobic digestion, and be present in treated biosolids. ?? 2008 American Chemical Society.

  8. The Research on Modeling and Simulation of TFE Polymerization Process

    Directory of Open Access Journals (Sweden)

    Jing Gao Sun

    2014-01-01

    Full Text Available PTFE (polytetrafluoroethylene is the fluorinated straight-chain polymer, made by the polymerization of tetrafluoroethylene monomer; it is used widely because of its excellent performance and can be obtained by the polymerization of body, solutions, suspensions, and emulsions. But only the last two are the main ways. This research paper makes simulation based on Polymer Plus. It uses the emulsion polymerization method at background to carry out a semibatch reactor system. Upon the actual production conditions, simulation process under the steady state conditions is used to analyze the effects of the changes on operating conditions; the corresponding dynamic model is created to analyze the impact of the changes of conditions on the entire system. Moreover, the amount of APS which plays an important part in this reaction is discussed for getting the most suitable amount of initiator. Because of less research work on this job, it is so difficult to find the related data from the literature. Therefore, this research will have a great significance for the process of the tetrafluoroethylene emulsion polymerization in the future.

  9. A review of thermal processing in the subsecond range: semiconductors and beyond

    Science.gov (United States)

    Rebohle, Lars; Prucnal, Slawomir; Skorupa, Wolfgang

    2016-10-01

    Thermal processing in the subsecond range comprises modern, non-equilibrium annealing techniques which allow various material modifications at the surface without affecting the bulk. Flash lamp annealing (FLA) is one of the most diverse methods for short-time annealing with applications ranging from the classical field of semiconductor doping to the treatment of polymers and flexible substrates. It still continues to extend its use to other material classes and applications, and is becoming of interest for an increasing number of users. In this review we present a short, but comprehensive and consistent picture of the current state-of-the-art of FLA, sometimes also called pulsed light sintering. In the first part we take a closer look at the physical and technological background, namely the electrical and optical specifications of flash lamps, the resulting temperature profiles, and the corresponding implications for process-relevant parameters such as reproducibility and homogeneity. The second part briefly considers the various applications of FLA, starting with the classical task of defect minimization and ultra-shallow junction formation in Si, followed by further applications in Si technology, namely in the fields of hyperdoping, crystallization of thin amorphous films, and photovoltaics. Subsequent chapters cover the topics of doping and crystallization in Ge and silicon carbide, doping of III-V semiconductors, diluted magnetic semiconductors, III-V nanocluster synthesis in Si, annealing of transparent conductive oxides and high-k materials, nanoclusters in dielectric matrices, and the use of FLA for flexible substrates.

  10. Process design and simulation of H2-rich gases production from biomass pyrolysis process.

    Science.gov (United States)

    Li, Chunshan; Suzuki, Kenzi

    2010-01-01

    In this study, biomass pyrolysis process for producing H(2)-rich gas is presented. The whole biomass pyrolysis process is established and simulated based on rigorous thermodynamic model, which includes pyrolysis reactor connecting one oil cracking reactor, water gas reactor and a gasifier. The simulation results are verified by the laboratory scale experimental measurements. Then, the influence of main operation parameters such as seam/biomass ratio, temperature (pyrolysis reactor, oil thermal cracking and gasifier) on the composition of fuel gas and hydrogen yield is discussed. Lastly, the optimization results are available. The results indicate that higher gas products and hydrogen yield can be obtained from the process, the H(2) yield can reach 83g/kg biomass, the H(2) concentration can reach 55% (mol) at the optimal temperature and steam/biomass ratio.

  11. Growth performance of free-range village chickens fed dehydrated processed food waste

    Directory of Open Access Journals (Sweden)

    Hossein, S.

    2015-06-01

    Full Text Available The effect of dehydrated processed food waste (DPFW inclusion in the diets on the growth performance (feed intake, body weight gain, body weight change and feed conversion ratio of free-range village chickens was investigated. Food waste collected from 20 different restaurants of Universiti Putra Malaysia Serdang Selangor was processed into DPFW containing 89.3% dry matter, 16% crude protein, 7.1% crude fat, 3.7% crude fiber, 7.4% crude ash, 3.07% NaCl, 1.56% Ca, 0.87% phosphorous and 4053 kcal/kg GE. A total of of 180 village chickens of the Arabian breed were randomly allocated into four dietary treatments of 0 (control, 20, 40 and 60% DPFW for 5-9 week grower and 10-14 week finisher periods with three replicates (15 birds for each replicate. The results showed that the highest feed intake in grower and finisher phases was observed in the control group by 634.0 g and 2,722.1 g, respectively, while the lowest was in 60% DPFW with 586.3 g for grower and 2,542.6 g for finisher phases (P0.05. Body weight gain and body weight change declined linearly with increasing levels of DPFW of more than 20% in the village chicken diets during both grower and finisher rearing phases. FAR increased (P0.05. In conclusion it seems that the dehydrated processed food waste could substitute 20% of formulated feed in grower and finisher phases of free-range village chickens without any adverse effects on growth performance.

  12. MATHEMATICAL SIMULATION OF CONCURRENT TWO-SIDED LENS PROCESSING

    Directory of Open Access Journals (Sweden)

    A. S. Kozeruk

    2015-01-01

    Full Text Available The purpose of the paper is to modernize technology for obtaining high-accuracy lenses with fine centre. Presently their operating surfaces are fixed  to an accessory with the help of adhesive substance that leads to elastic deformation in glass and causes local errors in lens parts.A mathematical model for concurrent two-sided processing of high-accuracy optical parts with spherical surfaces has been developed in the paper. The paper presents analytical expressions that permit to calculate sliding speed at any point on the processed spherical surface depending on type and value of technological equipment settings. Calculation of parameter Q = Pv in a diametric section of the convexo-concave lens has been carried out while using these expressions together with functional dependence of pressure on contact zone еarea of tool and part bedding surfaces.Theoretical and experimental investigations have been carried out with the purpose to study changes in Q parameter according to the processed lens surface for various setting parameters of the technological equipment and their optimum values ensuring preferential stock removal in the central or boundary part zone or uniform distribution of the removal along the whole processed surface have been determined in the paper.The paper proposes a machine tool scheme for concurrent two-sided grinding and polishing of lenses while fixing their side (cylindrical surface. Machine tool kinematics makes it possible flexibly and within wide limits to change its setting parameters  that significantly facilitates the control of form-building process of parts with highly-precise spherical surfaces.Methodology for investigations presupposes the following: mathematical simulation of highly-precise spherical surface form-building process under conditions of forced closing, execution of numerical and experimental studies.  

  13. Image simulation and a model of noise power spectra across a range of mammographic beam qualities.

    Science.gov (United States)

    Mackenzie, Alistair; Dance, David R; Diaz, Oliver; Young, Kenneth C

    2014-12-01

    The aim of this work is to create a model to predict the noise power spectra (NPS) for a range of mammographic radiographic factors. The noise model was necessary to degrade images acquired on one system to match the image quality of different systems for a range of beam qualities. Five detectors and x-ray systems [Hologic Selenia (ASEh), Carestream computed radiography CR900 (CRc), GE Essential (CSI), Carestream NIP (NIPc), and Siemens Inspiration (ASEs)] were characterized for this study. The signal transfer property was measured as the pixel value against absorbed energy per unit area (E) at a reference beam quality of 28 kV, Mo/Mo or 29 kV, W/Rh with 45 mm polymethyl methacrylate (PMMA) at the tube head. The contributions of the three noise sources (electronic, quantum, and structure) to the NPS were calculated by fitting a quadratic at each spatial frequency of the NPS against E. A quantum noise correction factor which was dependent on beam quality was quantified using a set of images acquired over a range of radiographic factors with different thicknesses of PMMA. The noise model was tested for images acquired at 26 kV, Mo/Mo with 20 mm PMMA and 34 kV, Mo/Rh with 70 mm PMMA for three detectors (ASEh, CRc, and CSI) over a range of exposures. The NPS were modeled with and without the noise correction factor and compared with the measured NPS. A previous method for adapting an image to appear as if acquired on a different system was modified to allow the reference beam quality to be different from the beam quality of the image. The method was validated by adapting the ASEh flat field images with two thicknesses of PMMA (20 and 70 mm) to appear with the imaging characteristics of the CSI and CRc systems. The quantum noise correction factor rises with higher beam qualities, except for CR systems at high spatial frequencies, where a flat response was found against mean photon energy. This is due to the dominance of secondary quantum noise in CR. The use of the

  14. Image simulation and a model of noise power spectra across a range of mammographic beam qualities

    Energy Technology Data Exchange (ETDEWEB)

    Mackenzie, Alistair, E-mail: alistairmackenzie@nhs.net; Dance, David R.; Young, Kenneth C. [National Coordinating Centre for the Physics of Mammography, Royal Surrey County Hospital, Guildford GU2 7XX, United Kingdom and Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Diaz, Oliver [Centre for Vision, Speech and Signal Processing, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, United Kingdom and Computer Vision and Robotics Research Institute, University of Girona, Girona 17071 (Spain)

    2014-12-15

    Purpose: The aim of this work is to create a model to predict the noise power spectra (NPS) for a range of mammographic radiographic factors. The noise model was necessary to degrade images acquired on one system to match the image quality of different systems for a range of beam qualities. Methods: Five detectors and x-ray systems [Hologic Selenia (ASEh), Carestream computed radiography CR900 (CRc), GE Essential (CSI), Carestream NIP (NIPc), and Siemens Inspiration (ASEs)] were characterized for this study. The signal transfer property was measured as the pixel value against absorbed energy per unit area (E) at a reference beam quality of 28 kV, Mo/Mo or 29 kV, W/Rh with 45 mm polymethyl methacrylate (PMMA) at the tube head. The contributions of the three noise sources (electronic, quantum, and structure) to the NPS were calculated by fitting a quadratic at each spatial frequency of the NPS against E. A quantum noise correction factor which was dependent on beam quality was quantified using a set of images acquired over a range of radiographic factors with different thicknesses of PMMA. The noise model was tested for images acquired at 26 kV, Mo/Mo with 20 mm PMMA and 34 kV, Mo/Rh with 70 mm PMMA for three detectors (ASEh, CRc, and CSI) over a range of exposures. The NPS were modeled with and without the noise correction factor and compared with the measured NPS. A previous method for adapting an image to appear as if acquired on a different system was modified to allow the reference beam quality to be different from the beam quality of the image. The method was validated by adapting the ASEh flat field images with two thicknesses of PMMA (20 and 70 mm) to appear with the imaging characteristics of the CSI and CRc systems. Results: The quantum noise correction factor rises with higher beam qualities, except for CR systems at high spatial frequencies, where a flat response was found against mean photon energy. This is due to the dominance of secondary quantum noise

  15. Simulation of signal and background processes for collider experiments

    Energy Technology Data Exchange (ETDEWEB)

    Schumann, S.

    2008-10-08

    In this thesis new theoretical tools for the accurate simulation of scattering processes at present and future collider experiments have been developed. Special emphasis has thereby to be given to multi-particle/multi-jet final states that often constitute signals for interesting (new) physics. Considering final states with a number of hard jets, there seems to be enough evidence that the traditional simulation tools HERWIG and PYTHIA cannot fully accomplish their description. Starting from a 2{yields}2 core process, they account only for soft and collinear QCD emissions through parton-shower models. Only recently, theoretical prescriptions have been found to consistently combine tree-level matrix-element calculations with the existing parton-shower algorithms. The gain of such methods is that phase-space regions covered by hard and by soft parton kinematics are simultaneously well described. In Chapter 2 of this thesis the working principles of such prescriptions have been discussed with special attention being paid to the merging scheme implemented in the SHERPA Monte Carlo. To consistently match QCD higher-order calculations (at one-loop or tree-level) with parton showers, a good analytical control over the perturbative terms present in the latter is required. This has triggered the demand for improved parton-shower models that facilitate the inclusion of exact matrix elements. In this line a completely new shower algorithm has been presented in Chapter 3. It is based on the Catani-Seymour dipole subtraction formalism, a universal method for calculating arbitrary processes at next-to-leading order in QCD. The splitting kernels used in the shower are justified approximations of the Catani-Seymour dipole functions. The kinematics of the individual splittings is accomplished such that exact four-momentum conservation can be ensured for each single branching. Accordingly, the shower can be stopped and started again at each intermediate stage of the evolution. The

  16. SIMULATION OF VINPOCETINE RELEASE PROCESS FROM MICROCAPSULES WITH HYDROPHOBIC SHELL

    Directory of Open Access Journals (Sweden)

    Yu. A. Polkovnikova

    2017-01-01

    Full Text Available Nowadays microcapsules are widely spread in different industries. Microcapsules with vitamins, etheric and fatty oils are included into different cosmetics (creams, gels, serums. Microencapsulated probiotics are used in foods and fodder additives in veterinary. An important field of application of microencapsulation in pharmacy is the combination in the total dosage of drugs that are incompatible when mixed in free form.The aim of work is a comparative analysis of thermodynamic characteristics of vinpocetine release from the melt of beeswax and cacao butter 3:2 into water, solution of hydrochloric acid 0.01 M and ethanol.Materials and methods. For simulation of the process of vinpocetine release from the melt into different environments models component models of the studied systems were built and their atom charges were calculated by quantum-chemical method. Spatial models of the components were built in Hyper Chem 8.01. As an initial state for the thermodynamic characteristics of the calculation of vinpocetine release from the melt, a conformation of «melt-vinpocetine» system was used after thermodynamic equilibration by molecular dynamics simulation in Bioeurica program for 5 ns. For isolated systems a vibrational analysis was performed with the use of unrestricted Hartree-Fock method in STO-3G basis set in Orca 4.0 program.Results and discussion. Vinpocetine release from the melt of beeswax and cacao butter 3:2 into water with different pH values and to ethanol depends on its solubility in these environments, and also on solubility of the melt.Conclusion. The performed study of vinpocetine release from the melt of beeswax and cacao butter 3:2 by molecular dynamics simulation demonstrates the opportunity of vinpocetine release into water with pH=2 and into ethanol. The obtained results make it possible to assume a lower degree of vinpocetine release from the melt into ethanol compared with the solution of hydrochloric acid 0,01 M.

  17. Cognitive processing load across a wide range of listening conditions: insights from pupillometry.

    Science.gov (United States)

    Zekveld, Adriana A; Kramer, Sophia E

    2014-03-01

    The pupil response to speech masked by interfering speech was assessed across an intelligibility range from 0% to 99% correct. In total, 37 participants aged between 18 and 36 years and with normal hearing were included. Pupil dilation was largest at intermediate intelligibility levels, smaller at high intelligibility, and slightly smaller at very difficult levels. Participants who reported that they often gave up listening at low intelligibility levels had smaller pupil dilations in these conditions. Participants who were good at reading masked text had relatively large pupil dilation when intelligibility was low. We conclude that the pupil response is sensitive to processing load, and possibly reflects cognitive overload in difficult conditions. It seems affected by methodological aspects and individual abilities, but does not reflect subjective ratings. Copyright © 2014 Society for Psychophysiological Research.

  18. Modelling and simulation of the consolidation behavior during thermoplastic prepreg composites forming process

    Science.gov (United States)

    Xiong, H.; Hamila, N.; Boisse, P.

    2017-10-01

    Pre-impregnated thermoplastic composites have recently attached increasing interest in the automotive industry for their excellent mechanical properties and their rapid cycle manufacturing process, modelling and numerical simulations of forming processes for composites parts with complex geometry is necessary to predict and optimize manufacturing practices, especially for the consolidation effects. A viscoelastic relaxation model is proposed to characterize the consolidation behavior of thermoplastic prepregs based on compaction tests with a range of temperatures. The intimate contact model is employed to predict the evolution of the consolidation which permits the microstructure prediction of void presented through the prepreg. Within a hyperelastic framework, several simulation tests are launched by combining a new developed solid shell finite element and the consolidation models.

  19. Simulation of the dust suppression process with foam in the areas of belt conveyors

    Directory of Open Access Journals (Sweden)

    Bespalov Vadim

    2017-01-01

    Full Text Available The article provides the analysis of the physical essence and simulation of the process of dust retention with foam in the air of working zones of belt conveyors transporting sand, crushed stone, gravel, coal, grain. In accordance with the proposed physical-energy concept of simulation of the process of dust control its physical essence is in a deliberate sequential action on the dust particles with previously prepared by the parameters external (additional dispersed systems. Use of dust retention technology foam method provides high efficiency of reducing the concentration of dust in the air of working areas of belt conveyors, which varies in the range of 85.0–99.0 %, which provides the standard level of dust contamination (MPC in air of working areas of listed industrial sources of formation and emission of dust.

  20. Process Simulation for the Design and Scale Up of Heterogeneous Catalytic Process: Kinetic Modelling Issues

    Directory of Open Access Journals (Sweden)

    Antonio Tripodi

    2017-05-01

    Full Text Available Process simulation represents an important tool for plant design and optimization, either applied to well established or to newly developed processes. Suitable thermodynamic packages should be selected in order to properly describe the behavior of reactors and unit operations and to precisely define phase equilibria. Moreover, a detailed and representative kinetic scheme should be available to predict correctly the dependence of the process on its main variables. This review points out some models and methods for kinetic analysis specifically applied to the simulation of catalytic processes, as a basis for process design and optimization. Attention is paid also to microkinetic modelling and to the methods based on first principles, to elucidate mechanisms and independently calculate thermodynamic and kinetic parameters. Different case studies support the discussion. At first, we have selected two basic examples from the industrial chemistry practice, e.g., ammonia and methanol synthesis, which may be described through a relatively simple reaction pathway and the relative available kinetic scheme. Then, a more complex reaction network is deeply discussed to define the conversion of bioethanol into syngas/hydrogen or into building blocks, such as ethylene. In this case, lumped kinetic schemes completely fail the description of process behavior. Thus, in this case, more detailed—e.g., microkinetic—schemes should be available to implement into the simulator. However, the correct definition of all the kinetic data when complex microkinetic mechanisms are used, often leads to unreliable, highly correlated parameters. In such cases, greater effort to independently estimate some relevant kinetic/thermodynamic data through Density Functional Theory (DFT/ab initio methods may be helpful to improve process description.

  1. CIVA: an expertise platform for simulation and processing NDT data.

    Science.gov (United States)

    Calmon, P; Mahaut, S; Chatillon, S; Raillon, R

    2006-12-22

    Ultrasonic modeling and simulation are more and more widely used by the different actors of industrial NDT. The applications are numerous and show a great variety: help for diagnosis, data reconstruction, performance demonstration, probe design and inspection parameters settling, virtual testing etc. The CEA (the French Atomic Energy Commission) is strongly involved in this evolution with the development of the CIVA expertise platform which gathers in the same software advanced processing and modeling tools. In the aim of fulfilling requirements of an intensive use the choice has been made to mainly adopt semi-analytical approximated methods. The wave propagation modeling is based on an integral formulation of the radiated field and applies the so-called pencil method. The modeling of beam-defect interaction and echoes formation mechanisms apply approximated theories such as Kirchhoff approximation or GTD. Over the years and with successive versions of the software, this approach is enriched by adaptations and improvements of the existing models or by new models, in order to extend the field of applicability of the simulation.

  2. Numerical Simulation and Investigation of System Parameters of Sonochemical Process

    Directory of Open Access Journals (Sweden)

    Sankar Chakma

    2013-01-01

    Full Text Available This paper presents the effects of various parameters that significantly affect the cavitation. In this study, three types of liquid mediums with different physicochemical properties were considered as the cavitation medium. The effects of various operating parameters such as temperature, pressure, initial bubble radius, dissolved gas content and so forth, were investigated in detail. The simulation results of cavitation bubble dynamics model showed a very interesting link among these parameters for production of oxidizing species. The formation of •OH radical and H2O2 is considered as the results of main effects of sonochemical process. Simulation results of radial motion of cavitation bubble dynamics revealed that bubble with small initial radius gives higher sonochemical effects. This is due to the bubble with small radius can undergo many acoustic cycles before reaching its critical radius when it collapses and produces higher temperature and pressure inside the bubble. On the other hand, due to the low surface tension and high vapor pressure, organic solvents are not suitable for sonochemical reactions.

  3. Process/Equipment Co-Simulation on Syngas Chemical Looping Process

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Liang; Zhou, Qiang; Fan, Liang-Shih

    2012-09-30

    The chemical looping strategy for fossil energy applications promises to achieve an efficient energy conversion system for electricity, liquid fuels, hydrogen and/or chemicals generation, while economically separate CO{sub 2} by looping reaction design in the process. Chemical looping particle performance, looping reactor engineering, and process design and applications are the key drivers to the success of chemical looping process development. In order to better understand and further scale up the chemical looping process, issues such as cost, time, measurement, safety, and other uncertainties need to be examined. To address these uncertainties, advanced reaction/reactor modeling and process simulation are highly desired and the modeling efforts can accelerate the chemical looping technology development, reduce the pilot-scale facility design time and operating campaigns, as well as reduce the cost and technical risks. The purpose of this work is thus to conduct multiscale modeling and simulations on the key aspects of chemical looping technology, including particle reaction kinetics, reactor design and operation, and process synthesis and optimization.

  4. Design and Implementation of Software for Resistance Welding Process Simulations

    DEFF Research Database (Denmark)

    Zhang, Wenqi

    2003-01-01

    Based on long time engineering research and dedicated collaborations with industry, a new welding software, SORPAS, has been developed for simulation of resistance projection and spot welding processes applying the powerful finite element method (FEM). In order to make the software directly usable...... by engineers and technicians in industry, all of the important parameters in resistance welding are considered and automatically implemented into the software. With the specially designed graphic user interface for Windows, engineers (even without prior knowledge of FEM) can quickly learn and easily operate...... and utilize the software. All industrial users, including welding engineers from DaimlerChrysler, Volkswangen, PSA Peugeot Citroen, VOLVO, Siemens, ABB and so on, have started using the software just after taking a one-day training course. With the user-friendly facilities for flexible geometric design...

  5. ATLAS simulation of boson plus jets processes in Run 2

    CERN Document Server

    The ATLAS collaboration

    2017-01-01

    This note describes the ATLAS simulation setup used to model the production of single electroweak bosons ($W$, $Z\\gamma^\\ast$ and prompt $\\gamma$) in association with jets in proton--proton collisions at centre-of-mass energies of 8 and 13 TeV. Several Monte Carlo generator predictions are compared in regions of phase space relevant for data analyses during the LHC Run-2, or compared to unfolded data distributions measured in previous Run-1 or early Run-2 ATLAS analyses. Comparisons are made for regions of phase space with or without additional requirements on the heavy-flavour content of the accompanying jets, as well as electroweak $Vjj$ production processes. Both higher-order corrections and systematic uncertainties are also discussed.

  6. Simulation of the ingot extraction in the continuous casting process

    Directory of Open Access Journals (Sweden)

    J. Szajnar

    2011-07-01

    Full Text Available Cast ingot pulling speed is significantly affecting the nature of the resulting structure and the quality of the outer surface of the ingot. By introducing a variable algorithm for extraction of the ingot we may to some extent control the shape and location of the solid / liquid interface and temperature field in the cross-section of the ingot. The shape of the crystallization front, as well as its position relative to mold plays an important role in the process of continuous casting ingots of grey iron and affects the structure of the casting. In order to verify the impact of an algorithm on the shape and the location of solid / liquid interface, a number of simulations in ANSYS Fluent 12 were made, for determining the shape of crystallization front and temperature distribution on the cross-section of the ingot.

  7. Simulation-based algorithms for Markov decision processes

    CERN Document Server

    Chang, Hyeong Soo; Fu, Michael C; Marcus, Steven I

    2013-01-01

    Markov decision process (MDP) models are widely used for modeling sequential decision-making problems that arise in engineering, economics, computer science, and the social sciences.  Many real-world problems modeled by MDPs have huge state and/or action spaces, giving an opening to the curse of dimensionality and so making practical solution of the resulting models intractable.  In other cases, the system of interest is too complex to allow explicit specification of some of the MDP model parameters, but simulation samples are readily available (e.g., for random transitions and costs). For these settings, various sampling and population-based algorithms have been developed to overcome the difficulties of computing an optimal solution in terms of a policy and/or value function.  Specific approaches include adaptive sampling, evolutionary policy iteration, evolutionary random policy search, and model reference adaptive search. This substantially enlarged new edition reflects the latest developments in novel ...

  8. A Friendly-Biological Reactor SIMulator (BioReSIM for studying biological processes in wastewater treatment processes

    Directory of Open Access Journals (Sweden)

    Raul Molina

    2014-12-01

    Full Text Available Biological processes for wastewater treatments are inherently dynamic systems because of the large variations in the influent wastewater flow rate, concentration composition and the adaptive behavior of the involved microorganisms. Moreover, the sludge retention time (SRT is a critical factor to understand the bioreactor performances when changes in the influent or in the operation conditions take place. Since SRT are usually in the range of 10-30 days, the performance of biological reactors needs a long time to be monitored in a regular laboratory demonstration, limiting the knowledge that can be obtained in the experimental lab practice. In order to overcome this lack, mathematical models and computer simulations are useful tools to describe biochemical processes and predict the overall performance of bioreactors under different working operation conditions and variations of the inlet wastewater composition. The mathematical solution of the model could be difficult as numerous biochemical processes can be considered. Additionally, biological reactors description (mass balance, etc. needs models represented by partial or/and ordinary differential equations associated to algebraic expressions, that require complex computational codes to obtain the numerical solutions. Different kind of software for mathematical modeling can be used, from large degree of freedom simulators capable of free models definition (as AQUASIM, to closed predefined model structure programs (as BIOWIN. The first ones usually require long learning curves, whereas the second ones could be excessively rigid for specific wastewater treatment systems. As alternative, we present Biological Reactor SIMulator (BioReSIM, a MATLAB code for the simulation of sequencing batch reactors (SBR and rotating biological contactors (RBC as biological systems of suspended and attached biomass for wastewater treatment, respectively. This BioReSIM allows the evaluation of simple and complex

  9. Processes and controlling factors of polygenetic dolomite formation in the Transdanubian Range, Hungary: a synopsis

    Science.gov (United States)

    Haas, János; Hips, Kinga; Budai, Tamás; Győri, Orsolya; Lukoczki, Georgina; Kele, Sándor; Demény, Attila; Poros, Zsófia

    2017-04-01

    In the Transdanubian Range (Hungary), dolostone and dolomitic limestone appear in a number of sedimentary successions formed from the Late Permian to the Late Triassic in various depositional settings and under various diagenetic conditions, whereas only a negligible amount of dolomite was detected in the post-Triassic formations. Seven dolomite-bearing units representing ramp, small and large carbonate platforms, and intraplatform basin settings are presented in this synopsis. In most cases, multi-stage and polygenetic dolomitization was inferred. The main mass of the dolostones was formed via near-surface diagenetic processes, which were commonly preceded by the formation of synsedimentary dolomite. Accordingly, surficial conditions that prevailed during sediment deposition controlled the dolomite-forming processes and thus the lateral extension and the time span of dolomitization. The area of episodic subaerial exposure was a critical controlling factor of the lateral extension of the near-surface dolomite genesis, whereas its temporal extension was mostly governed by climate. Burial diagenesis usually resulted in only moderate dolomitization, either in connection with compactional fluid flow or via thermal convection. The Triassic fault zones provided conduits for fluid flow that led to both replacive dolomitization and dolomite cement precipitation. In the Late Triassic extensional basins, synsedimentary fault-controlled dolomitization of basinal deposits was reconstructed.

  10. PROCESSING OF UAV BASED RANGE IMAGING DATA TO GENERATE DETAILED ELEVATION MODELS OF COMPLEX NATURAL STRUCTURES

    Directory of Open Access Journals (Sweden)

    T. K. Kohoutek

    2012-07-01

    Full Text Available Unmanned Aerial Vehicles (UAVs are more and more used in civil areas like geomatics. Autonomous navigated platforms have a great flexibility in flying and manoeuvring in complex environments to collect remote sensing data. In contrast to standard technologies such as aerial manned platforms (airplanes and helicopters UAVs are able to fly closer to the object and in small-scale areas of high-risk situations such as landslides, volcano and earthquake areas and floodplains. Thus, UAVs are sometimes the only practical alternative in areas where access is difficult and where no manned aircraft is available or even no flight permission is given. Furthermore, compared to terrestrial platforms, UAVs are not limited to specific view directions and could overcome occlusions from trees, houses and terrain structures. Equipped with image sensors and/or laser scanners they are able to provide elevation models, rectified images, textured 3D-models and maps. In this paper we will describe a UAV platform, which can carry a range imaging (RIM camera including power supply and data storage for the detailed mapping and monitoring of complex structures, such as alpine riverbed areas. The UAV platform NEO from Swiss UAV was equipped with the RIM camera CamCube 2.0 by PMD Technologies GmbH to capture the surface structures. Its navigation system includes an autopilot. To validate the UAV-trajectory a 360° prism was installed and tracked by a total station. Within the paper a workflow for the processing of UAV-RIM data is proposed, which is based on the processing of differential GNSS data in combination with the acquired range images. Subsequently, the obtained results for the trajectory are compared and verified with a track of a UAV (Falcon 8, Ascending Technologies carried out with a total station simultaneously to the GNSS data acquisition. The results showed that the UAV's position using differential GNSS could be determined in the centimetre to the decimetre

  11. Dynamic biogas upgrading based on the Sabatier process: thermodynamic and dynamic process simulation.

    Science.gov (United States)

    Jürgensen, Lars; Ehimen, Ehiaze Augustine; Born, Jens; Holm-Nielsen, Jens Bo

    2015-02-01

    This study aimed to investigate the feasibility of substitute natural gas (SNG) generation using biogas from anaerobic digestion and hydrogen from renewable energy systems. Using thermodynamic equilibrium analysis, kinetic reactor modeling and transient simulation, an integrated approach for the operation of a biogas-based Sabatier process was put forward, which was then verified using a lab scale heterogenous methanation reactor. The process simulation using a kinetic reactor model demonstrated the feasibility of the production of SNG at gas grid standards using a single reactor setup. The Wobbe index, CO2 content and calorific value were found to be controllable by the H2/CO2 ratio fed the methanation reactor. An optimal H2/CO2 ratio of 3.45-3.7 was seen to result in a product gas with high calorific value and Wobbe index. The dynamic reactor simulation verified that the process start-up was feasible within several minutes to facilitate surplus electricity use from renewable energy systems. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Validation of 30 nm process simulation using 3D TCAD for FinFET devices

    Science.gov (United States)

    Nawaz, Muhammad; Molzer, Wolfgang; Haibach, Patrick; Landgraf, Erhard; Roesner, Wolfgang; Staedele, Martin; Luyken, Hannes; Gencer, Alp

    2006-08-01

    This paper targets to show feasibility of a three-dimensional process simulation flow in the context of optimization of the device design and the underlying fabrication processes. The simulation is based on and refers to the development of the SOI-based 30 nm FinFET devices. The major goal of the simulation work is to implement a complete FinFET process flow into a commercially available 3D process simulation environment. Furthermore, all important three-dimensional geometrical features, such as corner roundings and 3D facets, have been introduced into the simulation set-up. After the successful demonstration of a functional 3D process simulation flow, detailed issues of process simulation methodology are assessed, such as the usage of different dopant diffusion models or the modelling of specific oxidation processes plus assessment of different annealing conditions. Finally, a comparison of the simulation results with electrical measurement data is performed which shows fairly good agreement.

  13. The CREST Simulation Development Process: Training the Next Generation.

    Science.gov (United States)

    Sweet, Robert M

    2017-04-01

    The challenges of training and assessing endourologic skill have driven the development of new training systems. The Center for Research in Education and Simulation Technologies (CREST) has developed a team and a methodology to facilitate this development process. Backwards design principles were applied. A panel of experts first defined desired clinical and educational outcomes. Outcomes were subsequently linked to learning objectives. Gross task deconstruction was performed, and the primary domain was classified as primarily involving decision-making, psychomotor skill, or communication. A more detailed cognitive task analysis was performed to elicit and prioritize relevant anatomy/tissues, metrics, and errors. Reference anatomy was created using a digital anatomist and clinician working off of a clinical data set. Three dimensional printing can facilitate this process. When possible, synthetic or virtual tissue behavior and textures were recreated using data derived from human tissue. Embedded sensors/markers and/or computer-based systems were used to facilitate the collection of objective metrics. A learning Verification and validation occurred throughout the engineering development process. Nine endourology-relevant training systems were created by CREST with this approach. Systems include basic laparoscopic skills (BLUS), vesicourethral anastomosis, pyeloplasty, cystoscopic procedures, stent placement, rigid and flexible ureteroscopy, GreenLight PVP (GL Sim), Percutaneous access with C-arm (CAT), Nephrolithotomy (NLM), and a vascular injury model. Mixed modalities have been used, including "smart" physical models, virtual reality, augmented reality, and video. Substantial validity evidence for training and assessment has been collected on systems. An open source manikin-based modular platform is under development by CREST with the Department of Defense that will unify these and other commercial task trainers through the common physiology engine, learning

  14. PROCESS SIMULATION AND QUALITY EVALUATION IN INCREMENTAL SHEET FORMING

    Directory of Open Access Journals (Sweden)

    Meftah Hrairi

    2011-12-01

    Full Text Available Single Point Incremental Forming (SPIF is a promising sheet-metal-forming process that permits the manufacturing of small to medium-sized batches of complex parts at low cost. It allows metal forming to work in the critical ‘necking-to-tearing' zone which results in a strong thinning before failure if the process is well designed. Moreover, the process is complex due to the number of variables involved. Thus, it is not possible to consider that the process has been well assessed; several remaining aspects need to be clarified. The objective of the present paper is to study some of these aspects, namely, the phenomenon of the wall thickness overstretch along depth and the effect of the tool path on the distribution of the wall thickness using finite element simulations.Abstrak: Pembentukan Tokokan Mata Tunggal (Single Point Incremental Forming (SPIF merupakan satu proses pembentukan kepingan logam yang membolehkan pembuatan dalam jumlah yang kecil hingga sederhana, bahagian-bahagian yang kompleks pada kos yang rendah. Jika proses ini direka dengan baik, kaedah ini membolehkan pembentukan logam yang baik terhasil. Jika tidak, semasa peringkat zon kritikal ‘perleheran-ke-pengoyakan' menyebabkan penipisan keterlaluan yang boleh menyebabkan logam tersebut rosak. Tambahan pula, proses ini agak kompleks, kerana ia melibatkan beberapa pemboleh ubah. Maka, walaupun proses ini telah dinilaikan seeloknya; masih terdapat beberapa aspek lain yang perlu diperjelaskan. Objektif kertas ini dibentangkan adalah untuk mengkaji beberapa aspek tertentu, seperti, ketebalan dinding regangan berlebihan di sepanjang kedalaman dan kesan tool path (beberapa siri posisi koordinat untuk menentukan pergerakan alatan memotong ketika operasi memesin terhadap pengagihan ketebalan dinding menggunakan simulasi unsur terhingga.

  15. A broad pH range and processive chitinase from a metagenome library

    Directory of Open Access Journals (Sweden)

    S.S. Thimoteo

    Full Text Available Chitinases are hydrolases that degrade chitin, a polymer of N-acetylglucosamine linked β(1-4 present in the exoskeleton of crustaceans, insects, nematodes and fungal cell walls. A metagenome fosmid library from a wastewater-contaminated soil was functionally screened for chitinase activity leading to the isolation and identification of a chitinase gene named metachi18A. The metachi18A gene was subcloned and overexpressed in Escherichia coli BL21 and the MetaChi18A chitinase was purified by affinity chromatography as a 6xHis-tagged fusion protein. The MetaChi18A enzyme is a 92-kDa protein with a conserved active site domain of glycosyl hydrolases family 18. It hydrolyses colloidal chitin with an optimum pH of 5 and temperature of 50°C. Moreover, the enzyme retained at least 80% of its activity in the pH range from 4 to 9 and 98% at 600 mM NaCl. Thin layer chromatography analyses identified chitobiose as the main product of MetaChi18A on chitin polymers as substrate. Kinetic analysis showed inhibition of MetaChi18A activity at high concentrations of colloidal chitin and 4-methylumbelliferyl N,N′-diacetylchitobiose and sigmoid kinetics at low concentrations of colloidal chitin, indicating a possible conformational change to lead the chitin chain from the chitin-binding to the catalytic domain. The observed stability and activity of MetaChi18A over a wide range of conditions suggest that this chitinase, now characterized, may be suitable for application in the industrial processing of chitin.

  16. Differential responses of invasive and native plants to warming with simulated changes in diurnal temperature ranges.

    Science.gov (United States)

    Chen, Bao-Ming; Gao, Yang; Liao, Hui-Xuan; Peng, Shao-Lin

    2017-07-01

    Although many studies have documented the effects of global warming on invasive plants, little is known about whether the effects of warming on plant invasion differ depending on the imposed change in different diurnal temperature ranges (DTR). We tested the impact of warming with DTR change on seed germination and seedling growth of eight species in the family Asteraceae. Four of these are invasive (Eupatorium catarium, Mikania micrantha, Biodens pilosa var. radiate, Ageratum conyzoides) in China, and four are native (Sonchus arvensis, Senecios candens, Pterocypsela indica, Eupatorium fortunei). Four temperature treatments were set in growth chambers (three warming by 3 °C with different DTRs and control), and experiments were run to mimic wintertime and summertime conditions. The control treatment (Tc ) was set to the mean temperature for the corresponding time of year, and the three warming treatments were symmetric (i.e. equal night-and-day) (DTRsym), asymmetric warming with increased (DTRinc) and decreased (DTRdec) DTR. The warming treatments did not affect seed germination of invasive species under any of the conditions, but DTRsym and DTRinc increased seed germination of natives relative to the control, suggesting that warming may not increase success of these invasive plant species via effects on seed germination of invasive plants relative to native plants. The invasive plants had higher biomass and greater stem allocation than the native ones under all of the warming treatments. Wintertime warming increased the biomass of the invasive and wintertime DTRsym and DTRinc increased that of the native plants, whereas summertime asymmetric warming decreased the biomass of the invasives but not the natives. Therefore, warming may not facilitate invasion of these invasive species due to the suppressive effects of summertime warming (particularly the asymmetric warming) on growth. Compared with DTRsym, DTRdec decreased the biomass of both the invasive and native

  17. Sub-Seasonal Predictability And Dynamical Processes: Long-Range Interactions

    Science.gov (United States)

    Brunet, G.

    2016-12-01

    World leading global forecasting systems in 2016 operate with around 20-100 ensemble members and a horizontal resolution in the range 13 to 50km with of order 100 vertical levels. We can currently predict large-scale weather patterns and regime transitions out to a month or more ahead and high-impact events, such as tropical cyclones, out to two weeks ahead. Under certain conditions, even sub-seasonal to seasonal forecasts have some predictive skill. Especially the intra-seasonal variability has a lot more degrees of freedom than seasonal variability and the associated dynamical and physical processes are numerous and complex. As an example research in the last three decades on tropical modes of ocean-atmosphere interaction, like the El Nino/Southern Oscillation (ENSO) oceanic phenomenon and its complex interaction between the large scale tropical atmosphere and organised moist convection, has permitted significant advances in seasonal prediction. Similarly research in the intra-seasonal variability has point out another ocean-atmosphere interaction mode, the Madden-Julian Oscillation (MJO), as an important source of predictability. MJO modulates significantly the mid-latitude intra-seasonal variability through tropical and mid-latitude teleconnections, like the Canadian winter temperature and precipitation. Another example is the two-way link between the MJO and the North Atlantic Oscillation (NAO) modulates significantly weather regimes over Western Europe. Pushing forecast leadtime to sub-seasonal scale will unfold a new landscape of predictability, model uncertainties and ensemble prediction issues. The richness of the sources of predictability associated with these processes could provide increase predictive skill in all seasons and regions. The associated socio-economic benefits are indeed promising to inform reliably the risk of high-impact weather, including tropical cyclones, droughts, floods, heat waves and the waxing and waning of monsoon precipitation

  18. Microtomographic imaging in the process of bone modeling and simulation

    Science.gov (United States)

    Mueller, Ralph

    1999-09-01

    Micro-computed tomography ((mu) CT) is an emerging technique to nondestructively image and quantify trabecular bone in three dimensions. Where the early implementations of (mu) CT focused more on technical aspects of the systems and required equipment not normally available to the general public, a more recent development emphasized practical aspects of micro- tomographic imaging. That system is based on a compact fan- beam type of tomograph, also referred to as desktop (mu) CT. Desk-top (mu) CT has been used extensively for the investigation of osteoporosis related health problems gaining new insight into the organization of trabecular bone and the influence of osteoporotic bone loss on bone architecture and the competence of bone. Osteoporosis is a condition characterized by excessive bone loss and deterioration in bone architecture. The reduced quality of bone increases the risk of fracture. Current imaging technologies do not allow accurate in vivo measurements of bone structure over several decades or the investigation of the local remodeling stimuli at the tissue level. Therefore, computer simulations and new experimental modeling procedures are necessary for determining the long-term effects of age, menopause, and osteoporosis on bone. Microstructural bone models allow us to study not only the effects of osteoporosis on the skeleton but also to assess and monitor the effectiveness of new treatment regimens. The basis for such approaches are realistic models of bone and a sound understanding of the underlying biological and mechanical processes in bone physiology. In this article, strategies for new approaches to bone modeling and simulation in the study and treatment of osteoporosis and age-related bone loss are presented. The focus is on the bioengineering and imaging aspects of osteoporosis research. With the introduction of desk-top (mu) CT, a new generation of imaging instruments has entered the arena allowing easy and relatively inexpensive access to

  19. Material processing with ultra-short pulse lasers working in 2μm wavelength range

    Science.gov (United States)

    Voisiat, B.; Gaponov, D.; Gečys, P.; Lavoute, L.; Silva, M.; Hideur, A.; Ducros, N.; Račiukaitis, G.

    2015-03-01

    New wavelengths of laser radiation are of interest for material processing. Results of application of the all-fiber ultrashort pulsed laser emitting in 2 µm range, manufactured by Novae, are presented. Average output power was 4.35 W in a single-spatial-mode beam centered at the 1950 nm wavelength. Pulses duration was 40 ps, and laser operated at 4.2 MHz pulse repetition rate. This performance corresponded to 25 kW of pulse peak power and almost 1 µJ in pulse energy. Material processing was performed using three different focusing lenses (100, 30 and 18 mm) and mechanical stages for the workpiece translation. 2 µm laser radiation is strongly absorbed by some polymers. Swelling of PMMA surface was observed for scanning speed above 5 mm/s using the average power of 3.45 W focused with the 30 mm lens. When scanning speed was reduced below 4 mm/s, ablation of PMMA took place. The swelling of PMMA is a consequence of its melting due to absorbed laser power. Therefore, experiments on butt welding of PMMA and overlapping welding of PMMA with other polymers were performed. Stable joint was achieved for the butt welding of two PMMA blocks with thickness of 5 mm. The laser was used to cut a Kapton film on a paper carrier with the same set-up as previous. The cut width depended on the cutting speed and focusing optics. A perfect cut with a width of 11 µm was achieved at the translation speed of 60 mm/s.

  20. 3D numerical simulation of the long range propagation of acoustical shock waves through a heterogeneous and moving medium

    Science.gov (United States)

    Luquet, David; Marchiano, Régis; Coulouvrat, François

    2015-10-01

    Many situations involve the propagation of acoustical shock waves through flows. Natural sources such as lightning, volcano explosions, or meteoroid atmospheric entries, emit loud, low frequency, and impulsive sound that is influenced by atmospheric wind and turbulence. The sonic boom produced by a supersonic aircraft and explosion noises are examples of intense anthropogenic sources in the atmosphere. The Buzz-Saw-Noise produced by turbo-engine fan blades rotating at supersonic speed also propagates in a fast flow within the engine nacelle. Simulating these situations is challenging, given the 3D nature of the problem, the long range propagation distances relative to the central wavelength, the strongly nonlinear behavior of shocks associated to a wide-band spectrum, and finally the key role of the flow motion. With this in view, the so-called FLHOWARD (acronym for FLow and Heterogeneous One-Way Approximation for Resolution of Diffraction) method is presented with three-dimensional applications. A scalar nonlinear wave equation is established in the framework of atmospheric applications, assuming weak heterogeneities and a slow wind. It takes into account diffraction, absorption and relaxation properties of the atmosphere, quadratic nonlinearities including weak shock waves, heterogeneities of the medium in sound speed and density, and presence of a flow (assuming a mean stratified wind and 3D turbulent ? flow fluctuations of smaller amplitude). This equation is solved in the framework of the one-way method. A split-step technique allows the splitting of the non-linear wave equation into simpler equations, each corresponding to a physical effect. Each sub-equation is solved using an analytical method if possible, and finite-differences otherwise. Nonlinear effects are solved in the time domain, and others in the frequency domain. Homogeneous diffraction is handled by means of the angular spectrum method. Ground is assumed perfectly flat and rigid. Due to the 3D

  1. 3D numerical simulation of the long range propagation of acoustical shock waves through a heterogeneous and moving medium

    Energy Technology Data Exchange (ETDEWEB)

    Luquet, David; Marchiano, Régis; Coulouvrat, François, E-mail: francois.coulouvrat@upmc.fr [Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR 7190, Institut Jean Le Rond d’Alembert, F-75005, Paris (France)

    2015-10-28

    Many situations involve the propagation of acoustical shock waves through flows. Natural sources such as lightning, volcano explosions, or meteoroid atmospheric entries, emit loud, low frequency, and impulsive sound that is influenced by atmospheric wind and turbulence. The sonic boom produced by a supersonic aircraft and explosion noises are examples of intense anthropogenic sources in the atmosphere. The Buzz-Saw-Noise produced by turbo-engine fan blades rotating at supersonic speed also propagates in a fast flow within the engine nacelle. Simulating these situations is challenging, given the 3D nature of the problem, the long range propagation distances relative to the central wavelength, the strongly nonlinear behavior of shocks associated to a wide-band spectrum, and finally the key role of the flow motion. With this in view, the so-called FLHOWARD (acronym for FLow and Heterogeneous One-Way Approximation for Resolution of Diffraction) method is presented with three-dimensional applications. A scalar nonlinear wave equation is established in the framework of atmospheric applications, assuming weak heterogeneities and a slow wind. It takes into account diffraction, absorption and relaxation properties of the atmosphere, quadratic nonlinearities including weak shock waves, heterogeneities of the medium in sound speed and density, and presence of a flow (assuming a mean stratified wind and 3D turbulent ? flow fluctuations of smaller amplitude). This equation is solved in the framework of the one-way method. A split-step technique allows the splitting of the non-linear wave equation into simpler equations, each corresponding to a physical effect. Each sub-equation is solved using an analytical method if possible, and finite-differences otherwise. Nonlinear effects are solved in the time domain, and others in the frequency domain. Homogeneous diffraction is handled by means of the angular spectrum method. Ground is assumed perfectly flat and rigid. Due to the 3D

  2. Computer simulation of energy use, greenhouse gas emissions, and process economics of the fluid milk process.

    Science.gov (United States)

    Tomasula, P M; Yee, W C F; McAloon, A J; Nutter, D W; Bonnaillie, L M

    2013-05-01

    Energy-savings measures have been implemented in fluid milk plants to lower energy costs and the energy-related carbon dioxide (CO2) emissions. Although these measures have resulted in reductions in steam, electricity, compressed air, and refrigeration use of up to 30%, a benchmarking framework is necessary to examine the implementation of process-specific measures that would lower energy use, costs, and CO2 emissions even further. In this study, using information provided by the dairy industry and equipment vendors, a customizable model of the fluid milk process was developed for use in process design software to benchmark the electrical and fuel energy consumption and CO2 emissions of current processes. It may also be used to test the feasibility of new processing concepts to lower energy and CO2 emissions with calculation of new capital and operating costs. The accuracy of the model in predicting total energy usage of the entire fluid milk process and the pasteurization step was validated using available literature and industry energy data. Computer simulation of small (40.0 million L/yr), medium (113.6 million L/yr), and large (227.1 million L/yr) processing plants predicted the carbon footprint of milk, defined as grams of CO2 equivalents (CO2e) per kilogram of packaged milk, to within 5% of the value of 96 g of CO 2e/kg of packaged milk obtained in an industry-conducted life cycle assessment and also showed, in agreement with the same study, that plant size had no effect on the carbon footprint of milk but that larger plants were more cost effective in producing milk. Analysis of the pasteurization step showed that increasing the percentage regeneration of the pasteurizer from 90 to 96% would lower its thermal energy use by almost 60% and that implementation of partial homogenization would lower electrical energy use and CO2e emissions of homogenization by 82 and 5.4%, respectively. It was also demonstrated that implementation of steps to lower non-process

  3. Comparative study of crystallization process in metallic melts using ab initio molecular dynamics simulations

    Science.gov (United States)

    Debela, Tekalign T.; Wang, X. D.; Cao, Q. P.; Zhang, D. X.; Jiang, J. Z.

    2017-05-01

    The crystallization process of liquid metals is studied using ab initio molecular dynamics simulations. The evolution of short-range order during quenching in Pb and Zn liquids is compared with body-centered cubic (bcc) Nb and V, and hexagonal closed-packed (hcp) Mg. We found that the fraction and type of the short-range order depends on the system under consideration, in which the icosahedral symmetry seems to dominate in the body-centered cubic metals. Although the local atomic structures in stable liquids are similar, liquid hcp-like Zn, bcc-like Nb and V can be deeply supercooled far below its melting point before crystallization while the supercooled temperature range in liquid Pb is limited. Further investigations into the nucleation process reveal the process of polymorph selection. In the body-centered cubic systems, the polymorph selection occurs in the supercooled state before the nucleation is initiated, while in the closed-packed systems it starts at the time of onset of crystallization. Atoms with bcc-like lattices in all studied supercooled liquids are always detected before the polymorph selection. It is also found that the bond orientational ordering is strongly correlated with the crystallization process in supercooled Zn and Pb liquids.

  4. Conversion of microalgae to jet fuel: process design and simulation.

    Science.gov (United States)

    Wang, Hui-Yuan; Bluck, David; Van Wie, Bernard J

    2014-09-01

    Microalgae's aquatic, non-edible, highly genetically modifiable nature and fast growth rate are considered ideal for biomass conversion to liquid fuels providing promise for future shortages in fossil fuels and for reducing greenhouse gas and pollutant emissions from combustion. We demonstrate adaptability of PRO/II software by simulating a microalgae photo-bio-reactor and thermolysis with fixed conversion isothermal reactors adding a heat exchanger for thermolysis. We model a cooling tower and gas floatation with zero-duty flash drums adding solids removal for floatation. Properties data are from PRO/II's thermodynamic data manager. Hydrotreating is analyzed within PRO/II's case study option, made subject to Jet B fuel constraints, and we determine an optimal 6.8% bioleum bypass ratio, 230°C hydrotreater temperature, and 20:1 bottoms to overhead distillation ratio. Process economic feasibility occurs if cheap CO2, H2O and nutrient resources are available, along with solar energy and energy from byproduct combustion, and hydrotreater H2 from product reforming. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Process of cracking in reinforced concrete beams (simulation and experiment

    Directory of Open Access Journals (Sweden)

    I. N. Shardakov

    2016-10-01

    Full Text Available The paper presents the results of experimental and theoretical investigations of the mechanisms of crack formation in reinforced concrete beams subjected to quasi-static bending. The boundary-value problem has been formulated in the framework of brittle fracture mechanics and solved using the finite-element method. Numerical simulation of the vibrations of an uncracked beam and a beam with cracks of different size serves to determine the pattern of changes in the spectrum of eigenfrequencies observed during crack evolution. A series of sequential quasi-static 4-point bend tests leading to the formation of cracks in a reinforced concrete beam were performed. At each loading step, the beam was subjected to an impulse load to induce vibrations. Two stages of cracking were detected. During the first stage the nonconservative process of deformation begins to develope, but has not visible signs. The second stage is an active cracking, which is marked by a sharp change in eingenfrequencies. The boundary of a transition from one stage to another is well registered. The vibration behavior was examined for the ordinary concrete beams and the beams strengthened with a carbon-fiber polymer. The obtained results show that the vibrodiagnostic approach is an effective tool for monitoring crack formation and assessing the quality of measures aimed at strengthening concrete structures

  6. Simulation of Forming Process as an Educational Tool Using Physical Modeling

    Science.gov (United States)

    Abdullah, A. B.; Muda, M. R.; Samad, Z.

    2008-01-01

    Metal forming process simulation requires a very high cost including the cost for dies, machine and material and tight process control since the process involve very huge pressure. A physical modeling technique is developed and initiates a new era of educational tool of simulating the process effectively. Several publications and findings have…

  7. Windthrow Dynamics in Boreal Ontario: A Simulation of the Vulnerability of Several Stand Types across a Range of Wind Speeds

    Directory of Open Access Journals (Sweden)

    Kenneth A. Anyomi

    2017-06-01

    Full Text Available In Boreal North America, management approaches inspired by the variability in natural disturbances are expected to produce more resilient forests. Wind storms are recurrent within Boreal Ontario. The objective of this study was to simulate wind damage for common Boreal forest types for regular as well as extreme wind speeds. The ForestGALES_BC windthrow prediction model was used for these simulations. Input tree-level data were derived from permanent sample plot (PSP data provided by the Ontario Ministry of Natural Resources. PSPs were assigned to one of nine stand types: Balsam fir-, Jack pine-, Black spruce-, and hardwood-dominated stands, and, Jack pine-, spruce-, conifer-, hardwood-, and Red and White pine-mixed species stands. Morphological and biomechanical parameters for the major tree species were obtained from the literature. At 5 m/s, predicted windthrow ranged from 0 to 20%, with damage increasing to 2 to 90% for winds of 20 m/s and to 10 to 100% for winds of 40 m/s. Windthrow varied by forest stand type, with lower vulnerability within hardwoods. This is the first study to provide such broad simulations of windthrow vulnerability data for Boreal North America, and we believe this will benefit policy decisions regarding risk management and forest planning.

  8. Virtual Earth System Laboratory (VESL): Effective Visualization of Earth System Data and Process Simulations

    Science.gov (United States)

    Quinn, J. D.; Larour, E. Y.; Cheng, D. L. C.; Halkides, D. J.

    2016-12-01

    The Virtual Earth System Laboratory (VESL) is a Web-based tool, under development at the Jet Propulsion Laboratory and UC Irvine, for the visualization of Earth System data and process simulations. It contains features geared toward a range of applications, spanning research and outreach. It offers an intuitive user interface, in which model inputs are changed using sliders and other interactive components. Current capabilities include simulation of polar ice sheet responses to climate forcing, based on NASA's Ice Sheet System Model (ISSM). We believe that the visualization of data is most effective when tailored to the target audience, and that many of the best practices for modern Web design/development can be applied directly to the visualization of data: use of negative space, color schemes, typography, accessibility standards, tooltips, etc cetera. We present our prototype website, and invite input from potential users, including researchers, educators, and students.

  9. The application of membrane technology for reuse of process water and minimisation of waste water in a textile washing range

    NARCIS (Netherlands)

    van t Hul, J.P.; Racz, I.G.; Reith, T.

    1997-01-01

    Recycling of process streams and reduction of waste disposal using membrane technology in a continuous textile washing process after dyeing with reactive dyes have been investigated theoretically. A mathematical process model of a conventional open-width washing range has been extended by membrane

  10. On the Monte Carlo simulation of electron transport in the sub-1 keV energy range.

    Science.gov (United States)

    Thomson, Rowan M; Kawrakow, Iwan

    2011-08-01

    The validity of "classic" Monte Carlo (MC) simulations of electron and positron transport at sub-1 keV energies is investigated in the context of quantum theory. Quantum theory dictates that uncertainties on the position and energy-momentum four-vectors of radiation quanta obey Heisenberg's uncertainty relation; however, these uncertainties are neglected in "classical" MC simulations of radiation transport in which position and momentum are known precisely. Using the quantum uncertainty relation and electron mean free path, the magnitudes of uncertainties on electron position and momentum are calculated for different kinetic energies; a validity bound on the classical simulation of electron transport is derived. In order to satisfy the Heisenberg uncertainty principle, uncertainties of 5% must be assigned to position and momentum for 1 keV electrons in water; at 100 eV, these uncertainties are 17 to 20% and are even larger at lower energies. In gaseous media such as air, these uncertainties are much smaller (less than 1% for electrons with energy 20 eV or greater). The classical Monte Carlo transport treatment is questionable for sub-1 keV electrons in condensed water as uncertainties on position and momentum must be large (relative to electron momentum and mean free path) to satisfy the quantum uncertainty principle. Simulations which do not account for these uncertainties are not faithful representations of the physical processes, calling into question the results of MC track structure codes simulating sub-1 keV electron transport. Further, the large difference in the scale at which quantum effects are important in gaseous and condensed media suggests that track structure measurements in gases are not necessarily representative of track structure in condensed materials on a micrometer or a nanometer scale.

  11. Short Range-Ordered Minerals: Insight into Aqueous Alteration Processes on Mars

    Science.gov (United States)

    Ming, D. W.; Morris, R. V.; Golden, D. C.

    2011-12-01

    Short range-ordered (SRO) aluminosilicates (e.g., allophane) and nanophase ferric oxides (npOx) are common SRO minerals derived during aqueous alteration of basaltic materials. NpOx refers to poorly crystalline or amorphous alteration products that can be any combination of superparamagnetic hematite and/or goethite, akaganeite, schwertmannite, ferrihydrite, iddingsite, and nanometer-sized ferric oxide particles that pigment palagonitic tephra. Nearly 30 years ago, SRO phases were suggested as alteration phases on Mars based on similar spectral properties for altered basaltic tephra on the slopes of Mauna Kea in Hawaii and Martian bright regions measured by Earth-based telescopes. Detailed characterization of altered basaltic tephra on Mauna Kea have identified a variety of alteration phases including allophane, npOx, hisingerite, jarosite, alunite, hematite, goethite, ferrihydrite, halloysite, kaolinite, smectite, and zeolites. The presence of npOx and other Fe-bearing minerals (jarosite, hematite, goethite) was confirmed by the Mössbauer Spectrometer onboard the Mars Exploration Rovers. Although the presence of allophane has not been definitely identified on Mars robotic missions, chemical analysis by the Spirit and Opportunity rovers and thermal infrared spectral orbital measurements suggest the presence of allophane or allophane-like phases on Mars. SRO phases form under a variety of environmental conditions on Earth ranging from cold and arid to warm and humid, including hydrothermal conditions. The formation of SRO aluminosilicates such as allophane (and crystalline halloysite) from basaltic material is controlled by several key factors including activity of water, extent of leaching, Si activity in solution, and available Al. Generally, a low leaching index (e.g., wet-dry cycles) and slightly acidic to alkaline conditions are necessary. NpOx generally form under aqueous oxidative weathering conditions, although thermal oxidative alteration may occasional be

  12. Short Range-Ordered Minerals: Insight into Aqueous Alteration Processes on Mars

    Science.gov (United States)

    Ming, Douglas W.; Morris, R. V.; Golden, D. C.

    2011-01-01

    Short range-ordered (SRO) aluminosilicates (e.g., allophane) and nanophase ferric oxides (npOx) are common SRO minerals derived during aqueous alteration of basaltic materials. NpOx refers to poorly crystalline or amorphous alteration products that can be any combination of superparamagnetic hematite and/or goethite, akaganeite, schwertmannite, ferrihydrite, iddingsite, and nanometer-sized ferric oxide particles that pigment palagonitic tephra. Nearly 30 years ago, SRO phases were suggested as alteration phases on Mars based on similar spectral properties for altered basaltic tephra on the slopes of Mauna Kea in Hawaii and Martian bright regions measured by Earth-based telescopes. Detailed characterization of altered basaltic tephra on Mauna Kea have identified a variety of alteration phases including allophane, npOx, hisingerite, jarosite, alunite, hematite, goethite, ferrihydrite, halloysite, kaolinite, smectite, and zeolites. The presence of npOx and other Fe-bearing minerals (jarosite, hematite, goethite) was confirmed by the M ssbauer Spectrometer onboard the Mars Exploration Rovers. Although the presence of allophane has not been definitely identified on Mars robotic missions, chemical analysis by the Spirit and Opportunity rovers and thermal infrared spectral orbital measurements suggest the presence of allophane or allophane-like phases on Mars. SRO phases form under a variety of environmental conditions on Earth ranging from cold and arid to warm and humid, including hydrothermal conditions. The formation of SRO aluminosilicates such as allophane (and crystalline halloysite) from basaltic material is controlled by several key factors including activity of water, extent of leaching, Si activity in solution, and available Al. Generally, a low leaching index (e.g., wet-dry cycles) and slightly acidic to alkaline conditions are necessary. NpOx generally form under aqueous oxidative weathering conditions, although thermal oxidative alteration may occasional be

  13. Simulating range-wide population and breeding habitat dynamics for an endangered woodland warbler in the face of uncertainty

    Science.gov (United States)

    Adam Duarte,; Hatfield, Jeffrey; Todd M. Swannack,; Michael R. J. Forstner,; M. Clay Green,; Floyd W. Weckerly,

    2015-01-01

    Population viability analyses provide a quantitative approach that seeks to predict the possible future status of a species of interest under different scenarios and, therefore, can be important components of large-scale species’ conservation programs. We created a model and simulated range-wide population and breeding habitat dynamics for an endangered woodland warbler, the golden-cheeked warbler (Setophaga chrysoparia). Habitat-transition probabilities were estimated across the warbler's breeding range by combining National Land Cover Database imagery with multistate modeling. Using these estimates, along with recently published demographic estimates, we examined if the species can remain viable into the future given the current conditions. Lastly, we evaluated if protecting a greater amount of habitat would increase the number of warblers that can be supported in the future by systematically increasing the amount of protected habitat and comparing the estimated terminal carrying capacity at the end of 50 years of simulated habitat change. The estimated habitat-transition probabilities supported the hypothesis that habitat transitions are unidirectional, whereby habitat is more likely to diminish than regenerate. The model results indicated population viability could be achieved under current conditions, depending on dispersal. However, there is considerable uncertainty associated with the population projections due to parametric uncertainty. Model results suggested that increasing the amount of protected lands would have a substantial impact on terminal carrying capacities at the end of a 50-year simulation. Notably, this study identifies the need for collecting the data required to estimate demographic parameters in relation to changes in habitat metrics and population density in multiple regions, and highlights the importance of establishing a common definition of what constitutes protected habitat, what management goals are suitable within those protected

  14. Combining short- and long-range fluorescence reporters with simulations to explore the intramolecular dynamics of an intrinsically disordered protein

    Science.gov (United States)

    Zosel, Franziska; Haenni, Dominik; Soranno, Andrea; Nettels, Daniel; Schuler, Benjamin

    2017-10-01

    Intrinsically disordered proteins (IDPs) are increasingly recognized as a class of molecules that can exert essential biological functions even in the absence of a well-defined three-dimensional structure. Understanding the conformational distributions and dynamics of these highly flexible proteins is thus essential for explaining the molecular mechanisms underlying their function. Single-molecule fluorescence spectroscopy in combination with Förster resonance energy transfer (FRET) is a powerful tool for probing intramolecular distances and the rapid long-range distance dynamics in IDPs. To complement the information from FRET, we combine it with photoinduced electron transfer (PET) quenching to monitor local loop-closure kinetics at the same time and in the same molecule. Here we employed this combination to investigate the intrinsically disordered N-terminal domain of HIV-1 integrase. The results show that both long-range dynamics and loop closure kinetics on the sub-microsecond time scale can be obtained reliably from a single set of measurements by the analysis with a comprehensive model of the underlying photon statistics including both FRET and PET. A more detailed molecular interpretation of the results is enabled by direct comparison with a recent extensive atomistic molecular dynamics simulation of integrase. The simulations are in good agreement with experiment and can explain the deviation from simple models of chain dynamics by the formation of persistent local secondary structure. The results illustrate the power of a close combination of single-molecule spectroscopy and simulations for advancing our understanding of the dynamics and detailed mechanisms in unfolded and intrinsically disordered proteins.

  15. Modelling and simulation of cure in pultrusion processes

    Science.gov (United States)

    Tucci, F.; Rubino, F.; Paradiso, V.; Carlone, P.; Valente, R.

    2017-10-01

    Trial and error approach is not a suitable method to optimize the pultrusion process because of the high times required for the start up and the wide range of possible combinations of matrix and reinforcement. On the other hand, numerical approaches can be a suitable solution to test different parameter configuration. One of the main tasks in pultrusion processes is to obtain a complete and homogeneous resin polymerization. The formation of cross-links between polymeric chains is thermally induced but it leads to a strong exothermic heat generation, hence the thermal and the chemical phenomena are mutually affected. It requires that the two problems have to be modelled in coupled way. The mathematical model used in this work considers the composite as a lumped material, whose thermal and mechanical properties are evaluated as function of resin and fibers properties. The numerical pattern is based on a quasi-static approach in a three-dimensional Eulerian domain, which describes both thermal and chemical phenomena. The data obtained are used in a simplified C.H.I.L.E. (Cure Hardening Instantaneous Linear Elastic) model to compute the mechanical properties of the resin fraction in the pultruded. The two combined approaches allow to formulate a numerical model which takes into account the normal (no-penetration) and tangential (viscosity/friction) interactions between die and profile, the pulling force and the hydrostatic pressure of the liquid resin to evaluate the stress and strain fields induced by the process within the pultruded. The implementation of the numerical models has been carried out using the ABAQUS finite element suite, by means of several user subroutines (in Fortran language) which improve the basic software potentialities.

  16. Assessment of alteration processes on circumstellar and interstellar grains in Queen Alexandra Range 97416

    Science.gov (United States)

    Bose, Maitrayee; Zega, Thomas J.; Williams, Peter

    2014-08-01

    Insight into the presolar and interstellar grain inventory of the CO3 chondrite Queen Alexandra Range (QUE) 97416 is gained through correlated secondary ion mass spectrometry (SIMS), transmission electron microscopy (TEM), and synchrotron-based X-ray absorption near-edge structure spectroscopy (XANES). Only one presolar silicate grain [O17/O16=(9.96±0.75)×10-4; O18/O16=(19.49±0.96)×10-4] that may have formed in a low-mass Red Giant or Asymptotic Giant Branch star occurs in the coarse-grained matrix of QUE 97416. No other presolar grains were identified. Although presolar grains are rare in QUE 97416, numerous (898±259 ppm) 15N-rich domains (δN15∼+1447‰ to +3069‰) occur in the thin section. Based on TEM of an extracted section, two 15N-rich domains are amorphous, C-bearing, and texturally uniform, and they are embedded in a ferromagnesian silicate matrix with varied grain sizes. The individual 15N-rich organic regions with high δN15 (+2942±107‰ and +2341±140‰) exhibit diverse carbon functional groups, such as aromatic, vinyl-keto, amidyl, and carboxylic functionality, while the nitrogen XANES reveals traces of nitrile functionality. QUE 97416 appears to have escaped aqueous alteration based on the absence of hydrated minerals but is thermally altered, which could have resulted in the destruction of presolar grains. However, this process at >400 °C metamorphic temperatures was inefficient in destroying the carriers of N isotope anomalies, which may indicate the resistant nature of the organic carriers and/or the limited extent of thermal metamorphism on the QUE 97416 parent body.

  17. Scenario Development Process at the Vertical Motion Simulator

    Science.gov (United States)

    Reardon, Scott E.; Beard, Steven D.; Lewis, Emily

    2017-01-01

    There has been a significant effort within the simulation community to standardize many aspects of flight simulation. More recently, an effort has begun to develop a formal scenario definition language for aviation. A working group within the AIAA Modeling and Simulation Technical Committee has been created to develop a standard aviation scenario definition language, though much of the initial effort has been tailored to training simulators. Research and development (R&D) simulators, like the Vertical Motion Simulator (VMS), and training simulators have different missions and thus have different scenario requirements. The purpose of this paper is to highlight some of the unique tasks and scenario elements used at the VMS so they may be captured by scenario standardization efforts. The VMS most often performs handling qualities studies and transfer of training studies. Three representative handling qualities simulation studies and two transfer of training simulation studies are described in this paper. Unique scenario elements discussed in this paper included special out-the-window (OTW) targets and environmental conditions, motion system parameters, active inceptor parameters, and configurable vehicle math model parameters.

  18. Process to Produce Iron Nanoparticle Lunar Dust Simulant Composite

    Science.gov (United States)

    Hung, Ching-cheh; McNatt, Jeremiah

    2010-01-01

    A document discusses a method for producing nanophase iron lunar dust composite simulant by heating a mixture of carbon black and current lunar simulant types (mixed oxide including iron oxide) at a high temperature to reduce ionic iron into elemental iron. The product is a chemically modified lunar simulant that can be attracted by a magnet, and has a surface layer with an iron concentration that is increased during the reaction. The iron was found to be -iron and Fe3O4 nanoparticles. The simulant produced with this method contains iron nanoparticles not available previously, and they are stable in ambient air. These nanoparticles can be mass-produced simply.

  19. Functional Decomposition of Modeling and Simulation Terrain Database Generation Process

    National Research Council Canada - National Science Library

    Yakich, Valerie R; Lashlee, J. D

    2008-01-01

    .... This report documents the conceptual procedure as implemented by Lockheed Martin Simulation, Training, and Support and decomposes terrain database construction using the Integration Definition for Function Modeling (IDEF...

  20. Material modeling for multistage tube hydroforming process simulation

    Science.gov (United States)

    Saboori, Mehdi

    The Aerospace industries of the 21st century demand the use of cutting edge materials and manufacturing technology. New manufacturing methods such as hydroforming are relatively new and are being used to produce commercial vehicles. This process allows for part consolidation and reducing the number of parts in an assembly compared to conventional methods such as stamping, press forming and welding of multiple components. Hydroforming in particular, provides an endless opportunity to achieve multiple crosssectional shapes in a single tube. A single tube can be pre-bent and subsequently hydroformed to create an entire component assembly instead of welding many smaller sheet metal sections together. The knowledge of tube hydroforming for aerospace materials is not well developed yet, thus new methods are required to predict and study the formability, and the critical forming limits for aerospace materials. In order to have a better understanding of the formability and the mechanical properties of aerospace materials, a novel online measurement approach based on free expansion test is developed using a 3D automated deformation measurement system (AramisRTM) to extract the coordinates of the bulge profile during the test. These coordinates are used to calculate the circumferential and longitudinal curvatures, which are utilized to determine the effective stresses and effective strains at different stages of the tube hydroforming process. In the second step, two different methods, a weighted average method and a new hardening function are utilized to define accurately the true stress-strain curve for post-necking regime of different aerospace alloys, such as inconel 718 (IN 718), stainless steel 321 (SS 321) and titanium (Ti6Al4V). The flow curves are employed in the simulation of the dome height test, which is utilized for generating the forming limit diagrams (FLDs). Then, the effect of stress triaxiality, the stress concentration factor and the effective plastic

  1. Simulation of Energy Savings in Automotive Coatings Processes

    Science.gov (United States)

    Gerini Romagnoli, Marco

    Recently, the automakers have become more and more aware of the environmental and economic impact of their manufacturing processes. The paint shop is the largest energy user in a vehicle manufacturing plant, and one way to reduce costs and energy usage is the optimization of this area. This project aims at providing a tool to model and simulate a paint shop, in order to run and analyze some scenarios and case studies, helping to take strategic decisions. Analytical computations and real data were merged to build a tool that can be used by FCA for their Sterling Heights plant. Convection and conduction heat losses were modeled for the dip processes and the ovens. Thermal balances were used to compute the consumptions of booths, decks and ovens, while pump and fan energy consumptions were modeled for each sub-process. The user acts on a calendar, scheduling a year of production, and the model predicts the energy consumption of the paint shop. Five scenarios were run to test different conditions and the influence of scheduling on the energy consumption. Two different sets of production schedules have been evaluated, the first one fulfilling the production requirement in one shift of 10 hours, at high rate, the second one using two 7-hour-long shifts at medium production rate. It was found that the unit cost was minimized in the warmest months of spring and fall, and system shutdown was a crucial factor to reduce energy consumption. A fifth hypothetical scenario was run, with a 4 month continuous production and an 8 month total shutdown, which reduced the energy consumption to a half of the best realistic scenario. When the plant was run in a two-shifts configuration, the cost to coat a vehicle was found to be 29 with weekend shutdown, and 39 without. In the one-shift configuration, the cost was slightly higher, but the difference was less than 5%. While the fifth scenario showed a consistent reduction of the unit cost, inventory and logistic expenses deriving from the

  2. NUMERICAL SIMULATION OF RESIDUAL STRESSES GENERATED IN THE WIRE DRAWING PROCESS FOR DIFFERENT PROCESS PARAMETERS

    Directory of Open Access Journals (Sweden)

    Juliana Zottis

    2014-03-01

    Full Text Available The drawing process of steel bars is usually used to check better dimensional accuracy and mechanical properties to the material. In the other hand, the major concern found in manufacturing axes through this process is the appearance of distortion of shape. Such distortions are directly linked to the accumulation of residual stresses generated during the processes. As a result, this paper aims to study the influence of process parameters such as shape of puller, speed and lubrication used in wire drawing analyzing the accumulation of residual stress after the process. The stress analysis was performed by FEM being used two simulation software: Simufact.formingGP and DeformTM. Through these analyzes, it was found that the shape of how the bar is pulled causes a reduction of up to 100 MPa in residual stresses in the center of the bar, which represents an important factor in the study of the possible causes of the distortion. As well as factors speed and homogeneity of lubrication significantly altered the profile of residual stresses in the bar.

  3. Preliminary Exploration of Simulation Preparation, Clinical Judgment and Reflective Process

    Directory of Open Access Journals (Sweden)

    Leighsa Sharoff

    2012-09-01

    Full Text Available Objective: How are clinical judgment and reflection enhanced with use of simulation is an area that requires exploration in addition to developing evidence about how best to prepare faculty and students for simulation. Simulation has proven to be an effective teaching strategy. Incorporating best practices to achieve optimal learning outcomes continues to require development. Methods: Triangulated evaluatory pilot study utilizing Survey Monkey for data collection. Seven students and 4 educators provided the convenience sample. Results: All participants felt more prepared with the prebriefing preparatory material. Students felt they had a better grasp of the simulation experience with sufficient understanding to respond effectively and decide on a course of nursing action to participate in patient care. Instructors felt more prepared with the additional information to effectively facilitate the simulation. Conclusions: Preparatory material enhanced simulation experience which further augmented clinical judgment and reflective practice. Simulation is essential to continued education of nursing students, preparing faculty and students for simulation improves outcomes. [J Contemp Med 2012; 2(3.000: 141-150

  4. Process modelling for air bending: validation by experiments and simulations

    NARCIS (Netherlands)

    Streppel, A.H.; Lutters, Diederick; ten Brinke, E.; Pijlman, H.H.; Kals, H.J.J.

    2001-01-01

    In order to evaluate and justify the use of bending simulations in e.g. CAPP applications, the simulations have to be compared to realistic samples from shop floor practice. However, input data concerning e.g. material behaviour, sheet thickness and tool geometry can be controlled in an adequate,

  5. Simulation models for food separation by adsorption process | Aoyi ...

    African Journals Online (AJOL)

    Separation of simulated industrial food products, by method of adsorption, has been studied. A thermodynamic approach has been applied to study the liquid adsorption where benzene and cyclohexane have been used to simulate edible oils in a system that employs silica gel as the adsorbent. Different models suggested ...

  6. Environmental Impact Analysis Process, Winnersville Weapons Range, Lanier and Lowndes Counties, Georgia

    Science.gov (United States)

    1985-11-01

    area and will adversely affect the value of all property in this area. The bombing range will also pose a greater danger to people and property. Just...tewer peopl., but only Echols County was considered. Particularly absurd is rhE lait (’i recited on Pg. IH that a range in Echols would n’,iulre

  7. Calibration and GEANT4 Simulations of the Phase II Proton Compute Tomography (pCT) Range Stack Detector

    Energy Technology Data Exchange (ETDEWEB)

    Uzunyan, S. A. [Northern Illinois Univ., DeKalb, IL (United States); Blazey, G. [Northern Illinois Univ., DeKalb, IL (United States); Boi, S. [Northern Illinois Univ., DeKalb, IL (United States); Coutrakon, G. [Northern Illinois Univ., DeKalb, IL (United States); Dyshkant, A. [Northern Illinois Univ., DeKalb, IL (United States); Francis, K. [Northern Illinois Univ., DeKalb, IL (United States); Hedin, D. [Northern Illinois Univ., DeKalb, IL (United States); Johnson, E. [Northern Illinois Univ., DeKalb, IL (United States); Kalnins, J. [Northern Illinois Univ., DeKalb, IL (United States); Zutshi, V. [Northern Illinois Univ., DeKalb, IL (United States); Ford, R. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Rauch, J. E. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Rubinov, P. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Sellberg, G. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Wilson, P. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Naimuddin, M. [Univ. of Delhi, New Delhi (India)

    2015-12-29

    Northern Illinois University in collaboration with Fermi National Accelerator Laboratory (FNAL) and Delhi University has been designing and building a proton CT scanner for applications in proton treatment planning. The Phase II proton CT scanner consists of eight planes of tracking detectors with two X and two Y coordinate measurements both before and after the patient. In addition, a range stack detector consisting of a stack of thin scintillator tiles, arranged in twelve eight-tile frames, is used to determine the water equivalent path length (WEPL) of each track through the patient. The X-Y coordinates and WEPL are required input for image reconstruction software to find the relative (proton) stopping powers (RSP) value of each voxel in the patient and generate a corresponding 3D image. In this Note we describe tests conducted in 2015 at the proton beam at the Central DuPage Hospital in Warrenville, IL, focusing on the range stack calibration procedure and comparisons with the GEANT~4 range stack simulation.

  8. Characterization of JG024, a pseudomonas aeruginosa PB1-like broad host range phage under simulated infection conditions

    Directory of Open Access Journals (Sweden)

    Rohde Manfred

    2010-11-01

    Full Text Available Abstract Background Pseudomonas aeruginosa causes lung infections in patients suffering from the genetic disorder Cystic Fibrosis (CF. Once a chronic lung infection is established, P. aeruginosa cannot be eradicated by antibiotic treatment. Phage therapy is an alternative to treat these chronic P. aeruginosa infections. However, little is known about the factors which influence phage infection of P. aeruginosa under infection conditions and suitable broad host range phages. Results We isolated and characterized a phage, named JG024, which infects a broad range of clinical and environmental P. aeruginosa strains. Sequencing of the phage genome revealed that the phage JG024 is highly related to the ubiquitous and conserved PB1-like phages. The receptor of phage JG024 was determined as lipopolysaccharide. We used an artificial sputum medium to study phage infection under conditions similar to a chronic lung infection. Alginate production was identified as a factor reducing phage infectivity. Conclusions Phage JG024 is a suitable broad host range phage which could be used in phage therapy. Phage infection experiments under simulated chronic lung infection conditions showed that alginate production reduces phage infection efficiency.

  9. Possibilities and importance of using computer games and simulations in educational process

    OpenAIRE

    Danilović Mirčeta S.

    2003-01-01

    The paper discusses if it is possible and appropriate to use simulations (simulation games) and traditional games in the process of education. It is stressed that the terms "game" and "simulation" can and should be taken in a broader sense, although they are chiefly investigated herein as video-computer games and simulations. Any activity combining the properties of game (competition, rules, players) and the properties of simulation (i.e. operational presentation of reality) should be underst...

  10. Emission characteristics of PBDEs during flame-retardant plastics extruding process: field investigation and laboratorial simulation.

    Science.gov (United States)

    Deng, Chao; Li, Ying; Li, Jinhui; Chen, Yuan; Li, Huafen

    2017-10-01

    Though mechanical recycling of WEEE plastics is supposed to be a promising method, PBDEs release and the resulting contamination during its processing remain unclear yet. The distribution of PBDEs pollution in production lines was investigated from two flame-retardant plastic modification plants in Southern China. This was followed by laboratory simulation experiments to characterize the emission processes. PBDEs concentrations ranged from 37 to 31,305 ng/L in cooling water and from 40,043 to 216,653 ng/g dry wt in solid samples taken during the field investigation. In the laboratory simulation, concentrations ranged from 146 to 433 ng/L in cooling water and from 411,436 to 747,516 ng/Nm3 in flue gas. All samples were dominated by BDE-209 among the congeners. Temperatures and impurities in plastic substrate can significantly affect PBDEs release. Special attention should be paid to the risks of water directly discharge from the cooling system, especially for the biological sludge and sediments, as well as flue gas emissions to the environment.

  11. Production of the entire range of r-process nuclides by black hole accretion disc outflows from neutron star mergers

    Science.gov (United States)

    Wu, Meng-Ru; Fernández, Rodrigo; Martínez-Pinedo, Gabriel; Metzger, Brian D.

    2016-12-01

    We consider r-process nucleosynthesis in outflows from black hole accretion discs formed in double neutron star and neutron star-black hole mergers. These outflows, powered by angular momentum transport processes and nuclear recombination, represent an important - and in some cases dominant - contribution to the total mass ejected by the merger. Here we calculate the nucleosynthesis yields from disc outflows using thermodynamic trajectories from hydrodynamic simulations, coupled to a nuclear reaction network. We find that outflows produce a robust abundance pattern around the second r-process peak (mass number A ˜ 130), independent of model parameters, with significant production of A < 130 nuclei. This implies that dynamical ejecta with high electron fraction may not be required to explain the observed abundances of r-process elements in metal poor stars. Disc outflows reach the third peak (A ˜ 195) in most of our simulations, although the amounts produced depend sensitively on the disc viscosity, initial mass or entropy of the torus, and nuclear physics inputs. Some of our models produce an abundance spike at A = 132 that is absent in the Solar system r-process distribution. The spike arises from convection in the disc and depends on the treatment of nuclear heating in the simulations. We conclude that disc outflows provide an important - and perhaps dominant - contribution to the r-process yields of compact binary mergers, and hence must be included when assessing the contribution of these systems to the inventory of r-process elements in the Galaxy.

  12. Predictive Simulation of Process Windows for Powder Bed Fusion Additive Manufacturing: Influence of the Powder Bulk Density.

    Science.gov (United States)

    Rausch, Alexander M; Küng, Vera E; Pobel, Christoph; Markl, Matthias; Körner, Carolin

    2017-09-22

    The resulting properties of parts fabricated by powder bed fusion additive manufacturing processes are determined by their porosity, local composition, and microstructure. The objective of this work is to examine the influence of the stochastic powder bed on the process window for dense parts by means of numerical simulation. The investigations demonstrate the unique capability of simulating macroscopic domains in the range of millimeters with a mesoscopic approach, which resolves the powder bed and the hydrodynamics of the melt pool. A simulated process window reveals the influence of the stochastic powder layer. The numerical results are verified with an experimental process window for selective electron beam-melted Ti-6Al-4V. Furthermore, the influence of the powder bulk density is investigated numerically. The simulations predict an increase in porosity and surface roughness for samples produced with lower powder bulk densities. Due to its higher probability for unfavorable powder arrangements, the process stability is also decreased. This shrinks the actual parameter range in a process window for producing dense parts.

  13. Simulating hydrologic and hydraulic processes throughout the Amazon River Basin

    Science.gov (United States)

    Beighley, R.E.; Eggert, K.G.; Dunne, T.; He, Y.; Gummadi, V.; Verdin, K.L.

    2009-01-01

    Presented here is a model framework based on a land surface topography that can be represented with various degrees of resolution and capable of providing representative channel/floodplain hydraulic characteristics on a daily to hourly scale. The framework integrates two models: (1) a water balance model (WBM) for the vertical fluxes and stores of water in and through the canopy and soil layers based on the conservation of mass and energy, and (2) a routing model for the horizontal routing of surface and subsurface runoff and channel and floodplain waters based on kinematic and diffusion wave methodologies. The WBM is driven by satellite-derived precipitation (TRMM_3B42) and air temperature (MOD08_M3). The model's use of an irregular computational grid is intended to facilitate parallel processing for applications to continental and global scales. Results are presented for the Amazon Basin over the period Jan 2001 through Dec 2005. The model is shown to capture annual runoff totals, annual peaks, seasonal patterns, and daily fluctuations over a range of spatial scales (>1, 000 to Amazon vary by approximately + /− 5 to 10 cm, and the fractional components accounting for these changes are: root zone soil moisture (20%), subsurface water being routed laterally to channels (40%) and channel/floodplain discharge (40%). Annual variability in monthly water storage changes by + /− 2·5 cm is likely due to 0·5 to 1 month variability in the arrival of significant rainfall periods throughout the basin.

  14. How interactions between animal movement and landscape processes modify range dynamics and extinction risk

    Science.gov (United States)

    Range dynamics models now incorporate many of the mechanisms and interactions that drive species distributions. However, connectivity continues to be studied using overly simple distance-based dispersal models with little consideration of how the individual behavior of dispersin...

  15. Formal Process Modeling to Improve Human Decision-Making in Test and Evaluation Acoustic Range Control

    Science.gov (United States)

    2017-09-01

    INTRODUCTION The purpose of this chapter is to present problems faced by undersea test ranges in the area of human decision-making and the lack of pre-test...noted that Range Officer training focuses on recognizing and understanding normal and expected conditions for the particular test and on using...These factors place increased burden on the test facility to conduct accurate and successful tests that produce the intended test conditions , which

  16. Simulation of business processes of processing and distribution of orders in transportation

    Directory of Open Access Journals (Sweden)

    Ольга Ігорівна Проніна

    2017-06-01

    Full Text Available Analyzing modern passenger transportation in Ukraine, we can conclude that with the increasing number of urban population the necessity to develop passenger traffic, as well as to improve the quality of transport services is increasing too. The paper examines the three existing models of private passenger transportation (taxi: a model with the use of dispatching service, without dispatching service model and a mixed model. An algorithm of getting an order, processing it, and its implementation according to the given model has been considered. Several arrangements schemes that characterize the operation of the system have been shown in the work as well. The interrelation of the client making an order and the driver who receives the order and executes it has been represented, the server being a connecting link between the customer and the driver and regulating the system as a whole. Business process of private passenger transportation without dispatching service was simulated. Basing on the simulation results it was proposed to supplement the model of private transportation by the making advice system, as well as improving the car selection algorithm. Advice system provides the optimum choice of the car, taking into account a lot of factors. And it will also make it possible to use more efficiently the specific additional services provided by the drivers. Due to the optimization of the order handling process it becomes possible to increase the capacity of the drivers thus increasing their profits. Passenger transportation without the use of dispatching service has some weak points and they were identified. Application of the system will improve transport structure in modern conditions, and improve the transportation basing on modern operating system

  17. Experiments and simulations show how long-range contacts can form in expanded unfolded proteins with negligible secondary structure.

    Science.gov (United States)

    Meng, Wenli; Lyle, Nicholas; Luan, Bowu; Raleigh, Daniel P; Pappu, Rohit V

    2013-02-05

    The sizes of unfolded proteins under highly denaturing conditions scale as N(0.59) with chain length. This suggests that denaturing conditions mimic good solvents, whereby the preference for favorable chain-solvent interactions causes intrachain interactions to be repulsive, on average. Beyond this generic inference, the broader implications of N(0.59) scaling for quantitative descriptions of denatured state ensembles (DSEs) remain unresolved. Of particular interest is the degree to which N(0.59) scaling can simultaneously accommodate intrachain attractions and detectable long-range contacts. Here we present data showing that the DSE of the N-terminal domain of the L9 (NTL9) ribosomal protein in 8.3 M urea lacks detectable secondary structure and forms expanded conformations in accord with the expected N(0.59) scaling behavior. Paramagnetic relaxation enhancements, however, indicate the presence of detectable long-range contacts in the denatured-state ensemble of NTL9. To explain these observations we used atomistic thermal unfolding simulations to identify ensembles whose properties are consistent with all of the experimental observations, thus serving as useful proxies for the DSE of NTL9 in 8.3 M urea. Analysis of these ensembles shows that residual attractions are present under mimics of good solvent conditions, and for NTL9 they result from low-likelihood, medium/long-range contacts between hydrophobic residues. Our analysis provides a quantitative framework for the simultaneous observation of N(0.59) scaling and low-likelihood long-range contacts for the DSE of NTL9. We propose that such low-likelihood intramolecular hydrophobic clusters might be a generic feature of DSEs that play a gatekeeping role to protect against aggregation during protein folding.

  18. Short-range precipitation forecasts using assimilation of simulated satellite water vapor profiles and column cloud liquid water amounts

    Science.gov (United States)

    Wu, Xiaohua; Diak, George R.; Hayden, Cristopher M.; Young, John A.

    1995-01-01

    These observing system simulation experiments investigate the assimilation of satellite-observed water vapor and cloud liquid water data in the initialization of a limited-area primitive equations model with the goal of improving short-range precipitation forecasts. The assimilation procedure presented includes two aspects: specification of an initial cloud liquid water vertical distribution and diabatic initialization. The satellite data is simulated for the next generation of polar-orbiting satellite instruments, the Advanced Microwave Sounding Unit (AMSU) and the High-Resolution Infrared Sounder (HIRS), which are scheduled to be launched on the NOAA-K satellite in the mid-1990s. Based on cloud-top height and total column cloud liquid water amounts simulated for satellite data a diagnostic method is used to specify an initial cloud water vertical distribution and to modify the initial moisture distribution in cloudy areas. Using a diabatic initialization procedure, the associated latent heating profiles are directly assimilated into the numerical model. The initial heating is estimated by time averaging the latent heat release from convective and large-scale condensation during the early forecast stage after insertion of satellite-observed temperature, water vapor, and cloud water formation. The assimilation of satellite-observed moisture and cloud water, together withy three-mode diabatic initialization, significantly alleviates the model precipitation spinup problem, especially in the first 3 h of the forecast. Experimental forecasts indicate that the impact of satellite-observed temperature and water vapor profiles and cloud water alone in the initialization procedure shortens the spinup time for precipitation rates by 1-2 h and for regeneration of the areal coverage by 3 h. The diabatic initialization further reduces the precipitation spinup time (compared to adiabatic initialization) by 1 h.

  19. Process of cracking in reinforced concrete beams (simulation and experiment)

    National Research Council Canada - National Science Library

    I N Shardakov; A P Shestakov; IO Glot; AA Bykov

    2016-01-01

    .... Numerical simulation of the vibrations of an uncracked beam and a beam with cracks of different size serves to determine the pattern of changes in the spectrum of eigenfrequencies observed during crack evolution...

  20. Single-Electron Transistor (SET) Process and Device Simulation Using SYSNOPSYS TCAD Tools

    OpenAIRE

    Uda Hashim; Amiza Rasmi

    2006-01-01

    Simulation of semiconductor device fabrication and operation is important to the design and manufacture of integrated circuits because it provides insights into complex phenomena that cannot obtained through experimentation or simple analytic models. Process and device simulation is commonly using for the design of new very large scale integration (VLSI) devices and processes. Simulation programs serves as exploratory tools in order to gain better understanding of process and device physics. ...

  1. Modeling and Simulation of - and Silicon Germanium-Base Bipolar Transistors Operating at a Wide Range of Temperatures.

    Science.gov (United States)

    Shaheed, M. Reaz

    1995-01-01

    to provide consistently accurate values for base sheet resistance for both Si- and SiGe-base transistors over a wide range of temperatures. A model for plasma-induced bandgap narrowing suitable for implementation in a numerical simulator has been developed. The appropriate method of incorporating this model in a drift -diffusion solver is described. The importance of including this model for low temperature simulation is demonstrated. With these models in place, the enhanced simulator has been used for evaluating and designing the Si- and SiGe-base bipolar transistors. Silicon-germanium heterojunction bipolar transistors offer significant performance and cost advantages over conventional technologies in the production of integrated circuits for communications, computer and transportation applications. Their high frequency performance at low cost, will find widespread use in the currently exploding wireless communication market. However, the high performance SiGe-base transistors are prone to have a low common-emitter breakdown voltage. In this dissertation, a modification in the collector design is proposed for improving the breakdown voltage without sacrificing the high frequency performance. A comprehensive simulation study of p-n-p SiGe-base transistors has been performed. Different figures of merit such as drive current, current gain, cut -off frequency and Early voltage were compared between a graded germanium profile and an abrupt germanium profile. The differences in the performance level between the two profiles diminishes as the base width is scaled down.

  2. A study of filling process for UV nanoimprint lithography using a fluid simulation

    Science.gov (United States)

    Yoneda, Ikuo; Nakagawa, Yasutada; Mikami, Shinji; Tokue, Hiroshi; Ota, Takumi; Koshiba, Takeshi; Ito, Masamitsu; Hashimoto, Koji; Nakasugi, Tetsuro; Higashiki, Tatsuhiko

    2009-03-01

    Nanoimprint lithography has advantages such as good resolution, CD uniformity and LER. However, nanoimprint lithography involves risks. In particular, defectivity is the most critical issue for nanoimprint lithography. Above all, the "non-fill defects" dominate such defects for UV nanoimprint. At the filling process of imprint resist, the capillary force that occurs between an imprint-resist and surface of template plays an important role. Our experience, suggests there is a relationship between the filling characteristics and pattern size of template. We also think the resist properties and the environmental conditions such as atmosphere pressure play important roles in the filling process. This paper explains the filling process dependency on the properties mentioned above. We analyzed the filling process using fluid simulation. At first, we assumed several pattern sizes with the same pattern height. Then, the filling times were estimated for each pattern size with various resist properties and the environmental conditions. An important attribute of our simulation model is the consideration accorded to the dissolution of gas between the template and imprint resist. As a result, the filling time of smaller pattern was found to be shorter than that of larger pattern. The assumed patterns are space and via on template ranging in size from 22nm width to 1000nm-width. The pattern height is 60nm. In this paper, we studied characteristics of filling mechanism by using fluid simulation. The relations between CD and filling time were obtained. We found that the gas dissolution rate is the dominant parameter for filling time.

  3. ASPEN Plus Simulation of CO2 Recovery Process

    Energy Technology Data Exchange (ETDEWEB)

    White, Charles W. [EG& G Technical Services, Inc., Morgantown, WV (United States)

    2002-09-30

    ASPEN Plus simulations have been created for a CO2 capture process based on adsorption by monoethanolamine (MEA). Three separate simulations were developed, one each for the flue gas scrubbing, recovery, and purification sections of the process. Although intended to work together, each simulation can be used and executed independently. The simulations were designed as template simulations to be added as a component to other more complex simulations. Applications involving simple cycle or hybrid power production processes were targeted. The default block parameters were developed based on a feed stream of raw flue gas of approximately 14 volume percent CO2 with a 90% recovery of the CO2 as liquid. This report presents detailed descriptions of the process sections as well as technical documentation for the ASPEN simulations including the design basis, models employed, key assumptions, design parameters, convergence algorithms, and calculated outputs.

  4. Processes Influencing Ozone Levels in Alaskan Forest Fires Plumes during Long-Range Transport over the North Atlantic

    Science.gov (United States)

    Real, E.; Law, K. S.; Wienzierl, B.; Fiebig, M.; Petzold, A.; Wild, O.; Methven, J.; Arnold, S.; Stohl, A.; Huntrieser, H.; hide

    2006-01-01

    A case of long-range transport of a biomass burning plume from Alaska to Europe is analyzed using a Lagrangian approach. This plume was sampled several times in the free troposphere over North America, the North Atlantic and Europe by 3 different aircraft during the IGAC Lagrangian 2K4 experiment which was part of the ICARTT/ITOP measurement intensive in summer 2004. Measurements in the plume showed enhanced values of CO, VOCs and NOy, mainly in form of PAN. Observed O3 levels increased by 17 ppbv over 5 days. A photochemical trajectory model, CiTTyCAT, is used to examine processes responsible for the chemical evolution of the plume. The model was initialized with upwind data, and compared with downwind measurements. The influence of high aerosol loading on photolysis rates in the plume is investigated using in-situ aerosol measurements in the plume and lidar retrievals of optical depth as input into a photolysis code (Fast-J), run in the model. Significant impacts on photochemistry are found with a decrease of 18 percent in O3 production and 24 percent in O3 destruction over 5 days when including aerosols. The plume is found to be chemically active with large O3 increases attributed primarily to PAN decomposition during descent of the plume towards Europe. The predicted O3 changes are very dependent on temperature changes during transport, and also, on water vapor levels in the lower troposphere which can lead to O3 destruction. Simulation of mixing/dilution was necessary to reproduce observed pollutants level in the plume. Mixing was simulated using background concentrations from measurements in air masses in close proximity to the plume, and mixing timescales (averaging 6.25 days) were derived from CO changes. Observed and simulated O3/CO correlations in the plume are also compared in order to evaluate the photochemistry in the model. Observed slopes changed from negative to positive over 5 days. This change, which can be attributed largely to photochemistry, is

  5. Application of Model-Based Signal Processing Methods to Computational Electromagnetics Simulators

    National Research Council Canada - National Science Library

    Ling, Hao

    2000-01-01

    This report summarizes the scientific progress on the research grant "Application of Model-Based Signal Processing Methods to Computational Electromagnetics Simulators" during the period 1 December...

  6. Annual Report on Application of Model-Based Signal Processing Methods to Computational Electromagnetics Simulators

    National Research Council Canada - National Science Library

    Ling, Hao

    1998-01-01

    This report summarizes the scientific progress on the research grant "Application of Model-Based Signal Processing Methods to Computational Electromagnetics Simulators" during the period 1 December...

  7. Application of Model-Based Signal Processing Methods to Computational Electromagnetics Simulators

    National Research Council Canada - National Science Library

    Ling, Hao

    1999-01-01

    This report summarizes the scientific progress on the research grant "Application of Model-Based Signal Processing Methods to Computational Electromagnetics Simulators" during the period 1 December...

  8. Optimization of Processes in a Freight Forwarding Company Using a Simulation Model

    Directory of Open Access Journals (Sweden)

    Sedláček Michal

    2017-01-01

    Full Text Available This paper discusses the possibilities of optimizing processes in forwarding companies that provide services in international truck transport. The computer simulation model was used to optimize logistics processes in the real distribution company. Software SIMUL8 was chosen as a development environment for its possibility of dynamic discrete simulation of company processes. This model will help us to analyze bottlenecks in company processes and find optimal solutions using simulation experiments. Optimization is focused on the company's warehouse, where a sequence of vehicles loading and unloading operations and emerging downtime are explored.

  9. Improvement of range spatial resolution of medical ultrasound imaging by element-domain signal processing

    Science.gov (United States)

    Hasegawa, Hideyuki

    2017-07-01

    The range spatial resolution is an important factor determining the image quality in ultrasonic imaging. The range spatial resolution in ultrasonic imaging depends on the ultrasonic pulse length, which is determined by the mechanical response of the piezoelectric element in an ultrasonic probe. To improve the range spatial resolution without replacing the transducer element, in the present study, methods based on maximum likelihood (ML) estimation and multiple signal classification (MUSIC) were proposed. The proposed methods were applied to echo signals received by individual transducer elements in an ultrasonic probe. The basic experimental results showed that the axial half maximum of the echo from a string phantom was improved from 0.21 mm (conventional method) to 0.086 mm (ML) and 0.094 mm (MUSIC).

  10. The weathering and transformation process of lead in China's shooting ranges.

    Science.gov (United States)

    Li, Yeling; Zhu, Yongbing; Zhao, Sanping; Liu, Xiaodong

    2015-09-01

    Corroding steel-core bullets from three shooting ranges in different climate zones of China were collected. Multiple technical methods (EMPA, SEM, XRD, and ICP-OES) were applied to investigate the structure, morphology, and weathering product of this type of bullet in China to analyze the weathering mechanisms in different types of soils. A scanning electron microscope (SEM) was used to view the morphology and microstructure of corrosion layers. On the corroded lead layer surface, unevenness, micro cracks, and spallation were usually present. Around the micro cracks, many types of euhedral and subhedral crystals of the secondary products of lead were formed, most of which were composed of cerussite (PbCO3), while hydrocerussite (Pb3(CO3)2(OH)2) was predominant in the bullet collected from the humid environment. X-ray power diffraction (XRD) results show that the secondary weathering products in the three shooting range soils are clearly different. In the Fangyan shooting range, which has a neutral and semi-arid soil, the lead weathering product was mainly hydrocerussite (Pb3(CO3)2(OH)2), while no substantial amount of crystal phase of lead compound could be found in acidic, damp soils from the Fenghuang shooting range, possibly due to the enhanced dissolution and mobilization of lead compounds at lower pH and higher content of organic matter in the soil. In hot and arid environment of the Baicheng shooting range, cerussite might have undergone thermal decomposition, thus generating shannonite (Pb2O(CO3)). These results indicate that the formation of secondary Pb minerals is largely affected by the climatic zone or the soil properties, which may have implications for range management practices.

  11. Towards a voxel-based geographic automata for the simulation of geospatial processes

    Science.gov (United States)

    Jjumba, Anthony; Dragićević, Suzana

    2016-07-01

    Many geographic processes evolve in a three dimensional space and time continuum. However, when they are represented with the aid of geographic information systems (GIS) or geosimulation models they are modelled in a framework of two-dimensional space with an added temporal component. The objective of this study is to propose the design and implementation of voxel-based automata as a methodological approach for representing spatial processes evolving in the four-dimensional (4D) space-time domain. Similar to geographic automata models which are developed to capture and forecast geospatial processes that change in a two-dimensional spatial framework using cells (raster geospatial data), voxel automata rely on the automata theory and use three-dimensional volumetric units (voxels). Transition rules have been developed to represent various spatial processes which range from the movement of an object in 3D to the diffusion of airborne particles and landslide simulation. In addition, the proposed 4D models demonstrate that complex processes can be readily reproduced from simple transition functions without complex methodological approaches. The voxel-based automata approach provides a unique basis to model geospatial processes in 4D for the purpose of improving representation, analysis and understanding their spatiotemporal dynamics. This study contributes to the advancement of the concepts and framework of 4D GIS.

  12. Enhancing Manufacturing Process Education via Computer Simulation and Visualization

    Science.gov (United States)

    Manohar, Priyadarshan A.; Acharya, Sushil; Wu, Peter

    2014-01-01

    Industrially significant metal manufacturing processes such as melting, casting, rolling, forging, machining, and forming are multi-stage, complex processes that are labor, time, and capital intensive. Academic research develops mathematical modeling of these processes that provide a theoretical framework for understanding the process variables…

  13. Axiomatic safety-critical assessment process (ASCAP) simulation methodology

    Energy Technology Data Exchange (ETDEWEB)

    Kaufman, L.M.; Giras, T.C. [Virginia Univ., Charlottesville, VA (United States). Center for Safety-Critical Ssytems

    2000-07-01

    The ASCAP simulation methodology models continuous train movement using a hybrid simulation consisting of both time and event driven portions. The actual train movement is predicated upon the solution of a series of discrete equations to determine its velocity, acceleration and braking profile at a specific time in tandem with the behavior of the train crew and the dispatcher agents in relationship to the behavioral states of the various stationary and mobile objects that a given train encounters. From this hybrid simulation, it is possible to generate accident scenarios. By performing multiple experiments to collect data for various accident scenarios, it will be possible to statistically quantify the risk associated with the various accident scenarios that are identified. (orig.)

  14. Simulation Process Analysis of Rubber Shock Absorber for Machine Tool

    Directory of Open Access Journals (Sweden)

    Chai Rong Xia

    2016-01-01

    Full Text Available The simulation on rubber shock absorber of machine tool was studied. The simple material model of rubber was obtained by through the finite element analysis software ABAQUS. The compression speed and the hardness of rubber material were considered to obtain the deformation law of rubber shock absorber. The location of fatigue were confirmed from the simulation results. The results shown that the fatigue position is distributed in the corner of shock absorber. The degree of deformation is increased with increasing of compress speed, and the hardness of rubber material is proportional to deformation.

  15. Process/Engineering Co-Simulation of Oxy-Combustion and Chemical Looping Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Sloan, David [Alstom Power Inc., Windsor, CT (United States)

    2013-03-01

    Over the past several years, the DOE has sponsored various funded programs, collectively referred to as Advanced Process Engineering Co-Simulator (APECS) programs, which have targeted the development of a steady-state simulator for advanced power plants. The simulator allows the DOE and its contractors to systematically evaluate various power plant concepts, either for preliminary conceptual design or detailed final design.

  16. Using manufacturing simulators to evaluate important processing decisions in the furniture and cabinet industries

    Science.gov (United States)

    Janice K. Wiedenbeck; Philip A. Araman

    1995-01-01

    We've been telling the wood industry about our process simulation modeling research and development work for several years. We've demonstrated our crosscut-first and rip-first rough mill simulation and animation models. Weâve advised companies on how they could use simulation modeling to help make critically important, pending decisions related to mill layout...

  17. Simulation of laser detection and ranging (LADAR) and forward-looking infrared (FLIR) data for autonomous tracking of airborne objects

    Science.gov (United States)

    Powell, Gavin; Markham, Keith C.; Marshall, David

    2000-06-01

    This paper presents the results of an investigation leading into an implementation of FLIR and LADAR data simulation for use in a multi sensor data fusion automated target recognition system. At present the main areas of application are in military environments but systems can easily be adapted to other areas such as security applications, robotics and autonomous cars. Recent developments have been away from traditional sensor modeling and toward modeling of features that are external to the system, such as atmosphere and part occlusion, to create a more realistic and rounded system. We have implemented such techniques and introduced a means of inserting these models into a highly detailed scene model to provide a rich data set for later processing. From our study and implementation we are able to embed sensor model components into a commercial graphics and animation package, along with object and terrain models, which can be easily used to create a more realistic sequence of images.

  18. Building Energy Simulation Test for Existing Homes (BESTEST-EX): Instructions for Implementing the Test Procedure, Calibration Test Reference Results, and Example Acceptance-Range Criteria

    Energy Technology Data Exchange (ETDEWEB)

    Judkoff, R.; Polly, B.; Bianchi, M.; Neymark, J.; Kennedy, M.

    2011-08-01

    This publication summarizes building energy simulation test for existing homes (BESTEST-EX): instructions for implementing the test procedure, calibration tests reference results, and example acceptance-range criteria.

  19. Micro Injection Moulding High Accuracy Three-Dimensional Simulations and Process Control

    DEFF Research Database (Denmark)

    Tosello, Guido; Costa, F.S.; Hansen, Hans Nørgaard

    2011-01-01

    Data analysis and simulations of micro‐moulding experiments have been conducted. Micro moulding simulations have been executed by implementing in the software the actual processing conditions. Various aspects of the simulation set‐up have been considered in order to improve the simulation accuracy......, injection pressure profile, moulding mass and flow pattern. The importance of calibrated micro moulding process monitoring for an accurate implementation strategy of the simulation and its validation has been demonstrated. In fact, inconsistencies and uncertainties in the experimental data must be minimized...

  20. Parallel computing with graphics processing units for high-speed Monte Carlo simulation of photon migration.

    Science.gov (United States)

    Alerstam, Erik; Svensson, Tomas; Andersson-Engels, Stefan

    2008-01-01

    General-purpose computing on graphics processing units (GPGPU) is shown to dramatically increase the speed of Monte Carlo simulations of photon migration. In a standard simulation of time-resolved photon migration in a semi-infinite geometry, the proposed methodology executed on a low-cost graphics processing unit (GPU) is a factor 1000 faster than simulation performed on a single standard processor. In addition, we address important technical aspects of GPU-based simulations of photon migration. The technique is expected to become a standard method in Monte Carlo simulations of photon migration.

  1. Design and application of a drip-type rainfall simulator adapted to steep topography and low intensity-rainfall characteristics in the Coastal Range of Southern Chile

    Science.gov (United States)

    Mohr, Christian; Anton, Huber

    2010-05-01

    Besides being adaptable for measuring infiltration, overland flow and sediment transport simultaneously, rainfall simulator systems allow the observation of the processes of runoff generation and soil erosion, too. This enables the assimilation of additional qualitative data and makes a rainfall simulator system a very valid method in the investigation of soil-hydrological response to precipitation events. In the present study a cheap, handy, transportable and easy to set up rainfall simulator applicable for the steep terrain conditions of the Southern Chilean Coastal range was designed based on Bowyer-Bower & Burt (1989). The used drip-type rainfall simulator had to fulfill two main requirements: adaptive to steep topography and little in water consumption. The used simulator is set up by a dismountable rectangular metal rack of 0.5x1.0m basal surface and 2.5m height. The metallic structure enables the attachment of plastic boards for wind protection. Fixable telescopic extensions allow a firm adjustment to slopes up to 45°. Horizontal metallic frames at different heights increase the stability of the structure and carry the devices of the rainfall simulator. On the uppermost frame, two containers provided with calibrated scales spend the water to a fast reacting receptacle assuring constant water supply and pressure by the Mariotte's principle. The rainfall intensity is adjusted by a control-panel according to the Bernoulli principle. This guarantees a constant water flow which was verified by the water-volume leaving the calibrated containers on top. Interchangeable glass-tubes of different diameters in the control-panel permit the generation of various precipitation intensities (4-60 mm/h; SD =0.16mm). The frame beneath carries an acrylic glass box with approx. 600 drop-formers (fishing line inside a 0.76mm Tygon-tube) at its bottom. 20 cm below, a framed 5mm-spacing-mesh serves as a raindrop randomizer. At the base of the simulator sheet metals avoid lateral

  2. Repeatability of Contour Method Residual Stress Measurements for a Range of Material, Process, and Geometry (Preprint)

    Science.gov (United States)

    2017-09-19

    titanium, and nickel, reflecting key industrial alloys . The set of conditions also includes a range of geometry, including plate, disk, and...for measurements. 2.2.3. Titanium Electron Beam Welded Plate Titanium alloy electron beam (EB) welded plate specimens were fabricated using one...right to use , modify, reproduce, release, perform, display, or disclose the work. 14. ABSTRACT (Maximum 200 words) This paper examines precision of

  3. Approaching a reliable process simulation for the virtual product development

    NARCIS (Netherlands)

    Kose, K.; Rietman, Bert; Tikhomirov, D.; Bessert, N.

    2005-01-01

    In this paper an outline for a strategy to include manufacturing effects in subsequent simulations for the virtual product development from an industrial point of view is given. Especially the conditions for a successful mapping of geometry and results between different applications are discussed.

  4. Process Simulation of Biobutanol Production from Lignocellulosic Feedstocks

    NARCIS (Netherlands)

    Procentese, A.; Guida, T.; Raganati, F.; Olivieri, G.; Salatino, P.; Marzocchella, A.

    2014-01-01

    A potential flowsheet to produce butanol production by conversion of a lignocellulosic biomass has been simulated by means of the software Aspen Plus®. The flowsheet has included upstream, fermentation, and downstream sections and the attention has been focused on the upstream section. The proposed

  5. Process Risk Assessment using Dynamic Simulation of Scenarios

    DEFF Research Database (Denmark)

    Markert, Frank; Kozin, Igor; Duijm, Nijs Jan

    2016-01-01

    (DES) of the scenarios, which is a Monte Carlo type method. The paper describes the application of DES to conduct the analysis part of a risk assessment that enables better time resolution in the modelling of the specific scenarios, simulate the interactions between concurrent chains of events under...

  6. Web-Based Modelling and Collaborative Simulation of Declarative Processes

    DEFF Research Database (Denmark)

    Slaats, Tijs; Marquard, Morten; Shahzad, Muhammad

    2015-01-01

    two years we have taken this adoption of DCR Graphs to the next level and decided to treat the notation as a product of its own by developing a stand-alone web-based collaborative portal for the modelling and simulation of declarative workflows. The purpose of the portal is to facilitate end...

  7. Gender Differences in Mental Simulation during Sentence and Word Processing

    Science.gov (United States)

    Wassenburg, Stephanie I.; de Koning, Björn B.; de Vries, Meinou H.; Boonstra, A. Marije; van der Schoot, Menno

    2017-01-01

    Text comprehension requires readers to mentally simulate the described situation by reactivating previously acquired sensory and motor information from (episodic) memory. Drawing upon research demonstrating gender differences, favouring girls, in tasks involving episodic memory retrieval, the present study explores whether gender differences exist…

  8. Challenges in Simulating Light-Induced Processes in DNA

    Directory of Open Access Journals (Sweden)

    Philipp Marquetand

    2016-12-01

    Full Text Available In this contribution, we give a perspective on the main challenges in performing theoretical simulations of photoinduced phenomena within DNA and its molecular building blocks. We distinguish the different tasks that should be involved in the simulation of a complete DNA strand subject to UV irradiation: (i stationary quantum chemical computations; (ii the explicit description of the initial excitation of DNA with light; (iii modeling the nonadiabatic excited state dynamics; (iv simulation of the detected experimental observable; and (v the subsequent analysis of the respective results. We succinctly describe the methods that are currently employed in each of these steps. While for each of them, there are different approaches with different degrees of accuracy, no feasible method exists to tackle all problems at once. Depending on the technique or combination of several ones, it can be problematic to describe the stacking of nucleobases, bond breaking and formation, quantum interferences and tunneling or even simply to characterize the involved wavefunctions. It is therefore argued that more method development and/or the combination of different techniques are urgently required. It is essential also to exercise these new developments in further studies on DNA and subsystems thereof, ideally comprising simulations of all of the different components that occur in the corresponding experiments.

  9. Numerical Integration with Graphical Processing Unit for QKD Simulation

    Science.gov (United States)

    2014-03-27

    6 2.1 Cryptography and Quantum Key Distribution Protocol . . . . . . . . . . . 6 2.1.1 Cryptography ...scientific research. 2.1 Cryptography and Quantum Key Distribution Protocol In order to have a better understanding of the QKD simulation a basic...information: From classical error correction to quantum cryptography . New York: Cambridge University Press, 1 ed., 2006. [7] C. H. Bennett and G. Brassard

  10. Arrival Processes for Vessels in a Port Simulation

    NARCIS (Netherlands)

    E. van Asperen (Eelco); R. Dekker (Rommert); M. Polman (Mark); H. de Swaan Arons; L. Waltman (Ludo)

    2003-01-01

    textabstractPorts provide jetty facilities for ships to load and unload their cargo. Jetty capacity is costly and therefore limited, causing delays for arriving ships. However, ship delays are also costly, so terminal operators attempt to min imize their number and duration. Here, simulation has

  11. Molecular dynamics simulations of cluster fission and fusion processes

    DEFF Research Database (Denmark)

    Lyalin, Andrey G.; Obolensky, Oleg I.; Solov'yov, Ilia

    2004-01-01

    Results of molecular dynamics simulations of fission reactions Na_10^2+ --> Na_7^+ +Na_3^+ and Na_18^2+ --> 2Na_9^+ are presented. The dependence of the fission barriers on the isomer structure of the parent cluster is analyzed. It is demonstrated that the energy necessary for removing homothetic...

  12. Simulation of the tube drawing process using the finite element method

    Science.gov (United States)

    Kassam, Zulfikar H. A.

    The power law and the Ramberg-Osgood constitutive equations are commonly used for describing material behavior. The Ramberg-Osgood equation is the more popular one as it is capable of describing behavior of several materials over the entire range of deformation. Previous research revealed, however, that the Ramberg-Osgood equation is not capable of describing the behavior of materials which exhibit sudden changes. One of the goals of this research was to develop a more accurate and efficient way of describing materials behavior. This goal has been achieved as a new equation, called the Alpha constitutive equation, has been developed. This equation is very accurate and efficient as well due to the ability of one equation being able to describe the behavior of any material---even materials that exhibit strain softening. The second phase of this research focused on developing a finite element program to simulate the tube drawing process which involves large plastic deformation and complicated boundary conditions. A specialized code to simulate the tube drawing in the presence of a mandrel has been developed. This finite element program has the ability to accept materials data in the form of a modified Ramberg-Osgood equation as well as the Alpha equation. A special technique was devised and implemented in the finite element program to avoid instability that tends to occur at the die exit. The finite element simulation results achieved in terms of the prediction of the drawing force compares well with the results obtained by Ontario Hydro Technologies. In addition, experiments conducted at Ontario Hydro revealed the formation of shear cracks on the outer surface of the tube. The finite element simulation results are consistent with this observation as the results indicate that maximum shear stress does exist at the outer walls of the tube which is responsible for the formation of shear cracks. The FEM program developed has the added advantage of having the capability

  13. Application of Tecnomatix Plant Simulation for Modeling Production and Logistics Processes

    Directory of Open Access Journals (Sweden)

    Julia Siderska

    2016-06-01

    Full Text Available The main objective of the article was to present the possibilities and examples of using Tecnomatix Plant Simulation (by Siemens to simulate the production and logistics processes. This tool allows to simulate discrete events and create digital models of logistic systems (e.g. production, optimize the operation of production plants, production lines, as well as individual logistics processes. The review of implementations of Tecnomatix Plant Simulation for modeling processes in production engineering and logistics was conducted and a few selected examples of simulations were presented. The author’s future studies are going to focus on simulation of production and logistic processes and their optimization with the use of genetic algorithms and artificial neural networks.

  14. Modified Range-Doppler Processing for FM-CW Synthetic Aperture Radar

    NARCIS (Netherlands)

    Wit, J.J.M. de; Meta, A.; Hoogeboom, P.

    2006-01-01

    The combination of compact frequency-modulated continuous-wave (FM-CW) technology and high-resolution synthetic aperture radar (SAR) processing techniques should pave the way for the development of a lightweight, cost-effective, high-resolution, airborne imaging radar. Regarding FM-CW SAR signal

  15. Symposium on intermediate-range atmospheric-transport processes and technology assessment. [Lead Abstract

    Energy Technology Data Exchange (ETDEWEB)

    1981-10-01

    Separate abstracts were prepared for the 47 papers in this proceedings. The purpose of this meeting was to assess the state of the art of modeling atmospheric transport processes 10 to 100 km downwind of point and area sources of pollution. (KRM)

  16. NASA Computational Case Study SAR Data Processing: Ground-Range Projection

    Science.gov (United States)

    Memarsadeghi, Nargess; Rincon, Rafael

    2013-01-01

    Radar technology is used extensively by NASA for remote sensing of the Earth and other Planetary bodies. In this case study, we learn about different computational concepts for processing radar data. In particular, we learn how to correct a slanted radar image by projecting it on the surface that was sensed by a radar instrument.

  17. White Sands Missile Range 2007 Urban Study: Data Processing - Volume DP-2 (Main Dataset)

    Science.gov (United States)

    2008-09-01

    were downloaded onto a thumb drive and sneaker -netted to a dedicated Excel spreadsheet for processing. Each of the resulting two datasets will be...Count Number Number List Tower Height (m AGL) Tower/Tripod Status 1 12 0637 NW 5 center NIST Calib 2 12 0638 NW 2.5 west NIST Calib 3 2 1330 SS 10 west

  18. Development of simulation program for analysis of thermoforming process; Sheet jukuseigata process no tame no kaiseki gijutsu no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, H.; Kihara, S.; Asano, K.; Ashibe, Y. [Sumitomo Heavy Industries, Ltd., Tokyo (Japan)

    1999-12-20

    Three-dimensional viscoelastic FEM code was developed to simulate thermoforming process of polymer sheet. The integral constitutive equation know as the K-BKZ model, where the stress is considered the integral of the time domain and some functions, is adopted and the model is newly formulated to solid element. Thermoforming process of a traveller's case was simulated. The validity of this method is demonstrated. (author)

  19. Bayesian integration of flux tower data into a process-based simulator for quantifying uncertainty in simulated output

    Science.gov (United States)

    Raj, Rahul; van der Tol, Christiaan; Hamm, Nicholas Alexander Samuel; Stein, Alfred

    2018-01-01

    Parameters of a process-based forest growth simulator are difficult or impossible to obtain from field observations. Reliable estimates can be obtained using calibration against observations of output and state variables. In this study, we present a Bayesian framework to calibrate the widely used process-based simulator Biome-BGC against estimates of gross primary production (GPP) data. We used GPP partitioned from flux tower measurements of a net ecosystem exchange over a 55-year-old Douglas fir stand as an example. The uncertainties of both the Biome-BGC parameters and the simulated GPP values were estimated. The calibrated parameters leaf and fine root turnover (LFRT), ratio of fine root carbon to leaf carbon (FRC : LC), ratio of carbon to nitrogen in leaf (C : Nleaf), canopy water interception coefficient (Wint), fraction of leaf nitrogen in RuBisCO (FLNR), and effective soil rooting depth (SD) characterize the photosynthesis and carbon and nitrogen allocation in the forest. The calibration improved the root mean square error and enhanced Nash-Sutcliffe efficiency between simulated and flux tower daily GPP compared to the uncalibrated Biome-BGC. Nevertheless, the seasonal cycle for flux tower GPP was not reproduced exactly and some overestimation in spring and underestimation in summer remained after calibration. We hypothesized that the phenology exhibited a seasonal cycle that was not accurately reproduced by the simulator. We investigated this by calibrating the Biome-BGC to each month's flux tower GPP separately. As expected, the simulated GPP improved, but the calibrated parameter values suggested that the seasonal cycle of state variables in the simulator could be improved. It was concluded that the Bayesian framework for calibration can reveal features of the modelled physical processes and identify aspects of the process simulator that are too rigid.

  20. Development of an Emergency Restoration Process Simulator of Electric Power Distribution Equipments after a Disaster

    Science.gov (United States)

    Sagai, Shigeo; Shumuta, Yoshiharu

    We are developing a tool which can simulate the emergency restoration process of electric power distribution facilities in order to examine the methods to speed-up the process. This report is aiming following two objectives; 1)describing an overview of the tool “restoration simulator” that simulates the emergency restoration process of the distribution facilities after a disaster, 2)evaluating effectiveness of various restoration methods to speed-up the restoration process using the tool.

  1. Grace: a Cross-platform Micromagnetic Simulator On Graphics Processing Units

    OpenAIRE

    Zhu, Ru

    2014-01-01

    A micromagnetic simulator running on graphics processing units (GPUs) is presented. Different from GPU implementations of other research groups which are predominantly running on NVidia’s CUDA platform, this simulator is developed with C++ Accelerated Massive Parallelism (C++ AMP) and is hardware platform independent. It runs on GPUs from venders including NVidia, AMD and Intel, and achieves significant performance boost as compared to previous central processing unit (CPU) simulators, up to ...

  2. Using Simulation Module, PCLAB, for Steady State Disturbance Sensitivity Analysis in Process Control

    Science.gov (United States)

    Ali, Emad; Idriss, Arimiyawo

    2009-01-01

    Recently, chemical engineering education moves towards utilizing simulation soft wares to enhance the learning process especially in the field of process control. These training simulators provide interactive learning through visualization and practicing which will bridge the gap between the theoretical abstraction of textbooks and the…

  3. Using a Readily Available Commercial Spreadsheet to Teach a Graduate Course on Chemical Process Simulation

    Science.gov (United States)

    Clarke, Matthew A.; Giraldo, Carlos

    2009-01-01

    Chemical process simulation is one of the most fundamental skills that is expected from chemical engineers, yet relatively few graduates have the opportunity to learn, in depth, how a process simulator works, from programming the unit operations to the sequencing. The University of Calgary offers a "hands-on" postgraduate course in…

  4. Combined Log Inventory and Process Simulation Models for the Planning and Control of Sawmill Operations

    Science.gov (United States)

    Guillermo A. Mendoza; Roger J. Meimban; Philip A. Araman; William G. Luppold

    1991-01-01

    A log inventory model and a real-time hardwood process simulation model were developed and combined into an integrated production planning and control system for hardwood sawmills. The log inventory model was designed to monitor and periodically update the status of the logs in the log yard. The process simulation model was designed to estimate various sawmill...

  5. A note on a perfect simulation algorithm for marked Hawkes processes

    DEFF Research Database (Denmark)

    Møller, Jesper; Rasmussen, Jakob Gulddahl

    2004-01-01

    The usual straightforward simulation algorithm for (marked or unmarked) Hawkes processes suffers from edge effect. In this note we describe a perfect simulation algorithm which is partly derived as in Brix and Kendall (2002) and partly using upper and lower processes as in the Propp-Wilson algori...

  6. The Process of Participatory Ergonomics Simulation in Hospital Work System Design

    DEFF Research Database (Denmark)

    Andersen, Simone Nyholm

    2016-01-01

    Participatory ergonomics simulation (PES) is a method to involve workers in simulation and design of their own future work system. Understanding of the process of PES is crucial in order to plan and facilitate the process towards creating an ergonomics work system design supporting both human well...

  7. Three-dimensional simulations of nanopowder compaction processes by granular dynamics method

    Science.gov (United States)

    Boltachev, G. Sh.; Lukyashin, K. E.; Shitov, V. A.; Volkov, N. B.

    2013-07-01

    In order to describe and to study the processes of cold compaction within the discrete element method a three-dimensional model of nanosized powder is developed. The elastic forces of repulsion, the tangential forces of “friction” (Cattaneo-Mindlin), and the dispersion forces of attraction (van der Waals-Hamaker), as well as the formation and destruction of hard bonds between the individual particles are taken into account. The monosized powders with the size of particles in the range 10-40 nm are simulated. The simulation results are compared to the experimental data of the alumina nanopowders compaction. It is shown that the model allows us to reproduce experimental data reliably and, in particular, describes the size effect in the compaction processes. A number of different external loading conditions is used in order to perform the theoretical and experimental researches. The uniaxial compaction (the closed-die compaction), the biaxial (radial) compaction, and the isotropic compaction (the cold isostatic pressing) are studied. The real and computed results are in a good agreement with each other. They reveal a weak sensitivity of the oxide nanopowders to the loading condition (compaction geometry). The application of the continuum theory of the plastically hardening porous body, which is usually used for the description of powders, is discussed.

  8. Simulations of ductile flow in brittle material processing

    Energy Technology Data Exchange (ETDEWEB)

    Luh, M.H.; Strenkowski, J.S.

    1988-12-01

    Research is continuing on the effects of thermal properties of the cutting tool and workpiece on the overall temperature distribution. Using an Eulerian finite element model, diamond and steel tools cutting aluminum have been simulated at various, speeds, and depths of cut. The relative magnitude of the thermal conductivity of the tool and the workpiece is believed to be a primary factor in the resulting temperature distribution in the workpiece. This effect is demonstrated in the change of maximum surface temperatures for diamond on aluminum vs. steel on aluminum. As a preliminary step toward the study of ductile flow in brittle materials, the relative thermal conductivities of diamond on polycarbonate is simulated. In this case, the maximum temperature shifts from the rake face of the tool to the surface of the machined workpiece, thus promoting ductile flow in the workpiece surface.

  9. Ground based snow water equivalent versus remotely sensed snow water extent assimilation for medium range streamflow simulation

    Science.gov (United States)

    Schaner, N. A.; Voisin, N.; Lettenmaier, D. P.

    2011-12-01

    In general, it is difficult for snow data assimilation to produce improvements in seasonal streamflow forecasts made with a well calibrated hydrological model when forced (up to the forecast time) by high quality gridded station data, because the uncertainty in the seasonal climate forecasts heavily influences streamflow forecast accuracy. On the other hand, improvements should be realizable for short to medium range (up to about 15 days) forecasts where the initial hydrologic conditions have more influence. Ground-based snow water equivalent (SWE) is observed at many locations across the western U.S., and is a state variable in most hydrological models, hence in principle can be assimilated directly into hydrologic models. However the challenge in assimilating SWE lies in the spatial disaggregation of point-based measurements in complex terrain and with varying observation density network, to the spatial resolution of hydrological models, which typically represent basin-average or grid cell-average (possibly with elevation bands) conditions, rather than points. The station-based SWE assimilation approach we consider here is taken from the University of Washington's West-Wide Seasonal Forecast system and uses the NRCS SNOw TELemetry (SNOTEL) network of about 600 stations across the mountainous West. The approach relies on a disaggregation using spatial and elevation-based weights. Satellite-derived Snow Cover Extent (SCE), in contrast, defines the spatial extent of the snow coverage but must rely on an empirical SCE-SWE relationship to produce estimates of SWE, which can then be assimilated. The direct insertion of SCE has not lead to much improvement in streamflow forecasts at seasonal lead times in previous studies, but our results show more marked improvements for shorter lead times. We evaluate the differences in potential forecast error reductions in medium range streamflow simulations (perfect forecast) for both SWE and SCE assimilation over the Feather River

  10. Range-resolved interferometric signal processing using sinusoidal optical frequency modulation.

    Science.gov (United States)

    Kissinger, Thomas; Charrett, Thomas O H; Tatam, Ralph P

    2015-04-06

    A novel signal processing technique using sinusoidal optical frequency modulation of an inexpensive continuous-wave laser diode source is proposed that allows highly linear interferometric phase measurements in a simple, self-referencing setup. Here, the use of a smooth window function is key to suppress unwanted signal components in the demodulation process. Signals from several interferometers with unequal optical path differences can be multiplexed, and, in contrast to prior work, the optical path differences are continuously variable, greatly increasing the practicality of the scheme. In this paper, the theory of the technique is presented, an experimental implementation using three multiplexed interferometers is demonstrated, and detailed investigations quantifying issues such as linearity and robustness against instrument drift are performed.

  11. On the performance of micro injection moulding process simulations of TPE micro rings

    DEFF Research Database (Denmark)

    Baruffi, Federico; Calaon, Matteo; Tosello, Guido

    of accurately capturing the position of the micro ring weld lines and air traps. Process simulations also correctly predicted the effects of the investigated process parameters on the part dimensions. The average deviation between real parts measurements and simulations results was 2 µm, demonstrating......Micro injection moulding (µIM) process simulations can be used as powerful tool for the optimization of the design of mould, part and process. However, numerous scale effects introduce relevant challenges in terms of both validation and accuracy of the simulations [1-2]. In this research, a case...... study based on µIM of thermoplastic elastomer (TPE) micro rings for sensor applications was treated. Injection moulding process simulations using Autodesk Moldflow Insight 2016® were applied with two main tasks: the first was the prediction of main parts defects. The second was the forecasting...

  12. Efficient simulation and process mechanics of incremental sheet forming

    NARCIS (Netherlands)

    Hadoush, A.

    2010-01-01

    Single Point Incremental Forming (SPIF) is a displacement controlled process performed on a CNC machine. A clamped blank is incrementally deformed by the movement of a small-sized tool that follows a prescribed lengthy tool path. The strain achieved by the SPIF process is higher than the strain

  13. Ready-to-Use Simulation: Demystifying Statistical Process Control

    Science.gov (United States)

    Sumukadas, Narendar; Fairfield-Sonn, James W.; Morgan, Sandra

    2005-01-01

    Business students are typically introduced to the concept of process management in their introductory course on operations management. A very important learning outcome here is an appreciation that the management of processes is a key to the management of quality. Some of the related concepts are qualitative, such as strategic and behavioral…

  14. Representing vegetation processes in hydrometeorological simulations using the WRF model

    DEFF Research Database (Denmark)

    Nielsen, Joakim Refslund

    -ments are still needed in the representation of the land surface variability and of some key land surface processes. This thesis explores two possibilities for improving the near-surface model predictions using the mesoscale Weather Research and Forecasting (WRF) model. In the _rst approach, data from satellite......For accurate predictions of weather and climate, it is important that the land surface and its processes are well represented. In a mesoscale model the land surface processes are calculated in a land surface model (LSM). These pro-cesses include exchanges of energy, water and momentum between...... the land surface components, such as vegetation and soil, and their interactions with the atmosphere. The land surface processes are complex and vary in time and space. Signi_cant e_ort by the land surface community has therefore been invested in improving the LSMs over the recent decades. However, improve...

  15. The Digital Simulation of Synchronous Motors Fed by Voltage-Source Inverters Over Wide Speed and Frequency Ranges

    Science.gov (United States)

    Rowihal, Said Soliman

    Both voltage-source and current-source inverters are widely used for supplying three-phase power to induction motor drives, each having their advantages and disadvantages. For high power drives and applications requiring accurate speed and tracking coordination, the synchronous motors are the optimum choice. For constant speed applications of synchronous motor drives, current-source inverters tend to be favored as the motor can usually be operated in the overexcited leading power factor region, thus providing the inverter with sufficient electro-motive force to allow natural commutation. Generally speaking low speed operation of synchronous motors is not satisfactory from naturally commutated current-source inverters. To provide a dynamic range of speed and frequency would require expensive control circuitry and complicates the performance of the drive. The advantage of the voltage-source inverter for the wide range of speed and frequency control herein envisaged is that forced commutation is employed throughout the range and the commutating circuits have been well developed and established. On balance, voltage-source inverters represent a viable compromise for variable-speed three -phase synchronous motor drives including start-up. To investigate the transient response of the voltage -source fed-synchronous motor drives, a digital computer program is developed. The program is based on two models --machine model and inverter model. The machine is represented by a detailed two-axis model which includes the effects due to saliency, damper windings, and machine resistances. The inverter model represents a forced-commutated voltage-source inverter assuming ideal switching devices (thyristors and diodes). To cope with the wide variations of power factor during start-up, a thyristor with a reverse connected parallel diode are integrated as a bidirectional switch. The digital program provides the machine variables of interest (phase currents, field current, damper winding

  16. Simulation and prediction of the thuringiensin abiotic degradation processes in aqueous solution by a radius basis function neural network model.

    Science.gov (United States)

    Zhou, Jingwen; Xu, Zhenghong; Chen, Shouwen

    2013-04-01

    The thuringiensin abiotic degradation processes in aqueous solution under different conditions, with a pH range of 5.0-9.0 and a temperature range of 10-40°C, were systematically investigated by an exponential decay model and a radius basis function (RBF) neural network model, respectively. The half-lives of thuringiensin calculated by the exponential decay model ranged from 2.72 d to 16.19 d under the different conditions mentioned above. Furthermore, an RBF model with accuracy of 0.1 and SPREAD value 5 was employed to model the degradation processes. The results showed that the model could simulate and predict the degradation processes well. Both the half-lives and the prediction data showed that thuringiensin was an easily degradable antibiotic, which could be an important factor in the evaluation of its safety. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Ultralong range ICD in the He dimer, resonant Auger - ICD cascade processes

    Energy Technology Data Exchange (ETDEWEB)

    Jahnke, Till [IKF, Goethe Universitaet, Max-von-Laue-Str.1, 60438 Frankfurt am Main (Germany)

    2013-07-01

    Interatomic (or intermolecular) Coulombic Decay (ICD) has become an extensively studied atomic decay process during the last 10 years. The talk shows examples of different systems in which ICD has been examined. In particular helium molecules (so called helium dimers) are presented in which ICD occurs over longest internuclear distances. In ICD electrons of low energy are created as a typical decay product. Such electrons are known to effectively cause DNA double strand breakups suggesting ICD as a possible origin for radiation damage of living tissue. The group of L. Cederbaum recently suggested that ICD can be triggered efficiently and site-selectively by resonant excitation of molecules. They realized that this provides a unique tool to create low energy electrons at a specific site inside a biological system for example in order to damage malignant cells that are tagged using specific marker molecules. Here we show experimentally that resonant Auger induced ICD can indeed be observed in model systems of small nitrogen and carbon monoxide clusters and - as expected - produces low energy electrons. Furthermore our simple model systems are able to prove the efficiency of ICD: it occurs before the individual molecule is able to undergo dissociation, i.e on a timescale <10 fs. Our findings therefore strongly support the idea of resonant Auger-ICD being a promising process to induce radiation damage at a specific site inside a high-Z-tagged cell.

  18. Computer Simulation Methods for Crushing Process in an Jaw Crusher

    Science.gov (United States)

    Il'ich Beloglazov, Ilia; Andreevich Ikonnikov, Dmitrii

    2016-08-01

    One of the trends at modern mining enterprises is the application of combined systems for extraction and transportation of the rock mass. Given technology involves the use the conveyor lines as a continuous link of combined technology. The application of a conveyor transport provides significant reduction of costs for energy resources, increase in labor productivity and process automation. However, the use of a conveyor transport provides for certain requirements for the quality of transported material. The maximum size of the rock mass pieces is one of the basic parameters for it. The crushing plants applies as a coarse crushing followed by crushing the material to the maximum size of piece which possible to use for conveyor transport. It is often represented by jaw crushers. Modelling of crushing process in jaw crushers allows to maximally optimize workflow and increase efficiency of the equipment at the further transportation and processing of rocks. We studied the interaction between walls of the jaw crusher and bulk material by using discrete element method (DEM) in this paper. The article examines the process of modeling by stages. It includes design of the crusher construction in solid and surface modeling system. Modelling of the crushing process based on the experimental data received via the crushing unit BOYD. The process of destruction and particle size distribution in the study was done. Analysis of research results shows a comparability of actual experiment and modeling process.

  19. Research in materials processing using a low gravity simulation aircraft

    Science.gov (United States)

    Owen, Robert B.

    1987-01-01

    The feasibility of performing materials experiments aboard the NASA KC-135 low gravity simulation aircraft is demonstrated. The vehicle serves as a research platform which flies parabolic maneuvers. Experiments which have been conducted on board the aircraft are outlined and particular attention is given to tests utilizing optical measurement techniques such as interferometry, schlieren, and holography. It is noted that the KC-135 can be used for crew training, flight hardware checkout, conceptual development, self-sufficient experiments, and research in support of and leading to space flight experiments.

  20. Gate design in injection molding of microfluidic components using process simulations

    DEFF Research Database (Denmark)

    Marhöfer, David Maximilian; Tosello, Guido; Islam, Aminul

    Process simulations are an effective design and optimization tool in conventional as well as micro injection molding (μIM). They can be applied to optimize and assist the design of the micro part, the mold, the micro cavity and the μIM process. Available simulation software is however developed...... to moulding process window, polymer flow, and part quality. This finally led to an optimization of the design and the realization as actual steel mold. Additionally, the simulation results were critically discussed and possible improvements and limitations of the gained results and the deployed software...... are presented. Ultimately, the simulation results were validated by comparing the flow pattern behavior of the polymer flow predicted by the simulation with the actual flow front at different time steps. These were realized by molding short shots with the realized molds and were compared to the simulations...

  1. Carbon nanotube vacuum gauges with wide-dynamic range and processes thereof

    Science.gov (United States)

    Manohara, Harish (Inventor); Kaul, Anupama B. (Inventor)

    2013-01-01

    A miniature thermal conductivity gauge employs a carbon single-walled-nanotube. The gauge operates on the principle of thermal exchange between the voltage-biased nanotube and the surrounding gas at low levels of power and low temperatures to measure vacuum across a wide dynamic range. The gauge includes two terminals, a source of constant voltage to the terminals, a single-walled carbon nanotube between the terminals, a calibration of measured conductance of the nanotube to magnitudes of surrounding vacuum and a current meter in electrical communication with the source of constant voltage. Employment of the nanotube for measuring vacuum includes calibrating the electrical conductance of the nanotube to magnitudes of vacuum, exposing the nanotube to a vacuum, applying a constant voltage across the nanotube, measuring the electrical conductance of the nanotube in the vacuum with the constant voltage applied and converting the measured electrical conductance to the corresponding calibrated magnitude of vacuum using the calibration. The nanotube may be suspended to minimize heat dissipation through the substrate, increasing sensitivity at even tower pressures.

  2. Dynamical effects and time scale in fission processes in nuclear collisions in the Fermi energy range

    Energy Technology Data Exchange (ETDEWEB)

    Colin, J.; Bocage, F.; Louvel, M. [Laboratoire de Physique Corpusculaire, IN2P3-CNRS, ISMRA et Universite, 14 - Caen (France)] [and others

    1999-10-01

    Recent experimental results concerning heavy systems (Pb+Au, Pb+Ag, Pb+Al, Gd+U, Gd+C, Ta+Au, U+U, U+C, Xe+Sn...) obtained at Ganil by the Indra and Nautilus collaborations will be presented. A study of reaction mechanisms has shown the dominant binary and highly dissipative character of the process. The two heavy and excited fragments produced after the first stage of the interaction can experience various decay modes: evaporation, fission, multifragmentation. However, deviations from this simple picture have been found by analysing angular and velocity distribution of light charge particles, IMF's (Intermediate Mass Fragment) and fragments. Indeed, there is an amount of matter in excess emitted in-between the two primary sources suggesting either the existence of a mi-rapidity source similar to the one observed in the relativistic regime (participants) or a strong deformation induced by the dynamics of the collision (neck instability). This last scenario is explored by analysing in details the angular distributions of the fission fragments. More precisely, we observed two components: the first one is isotropic and consistent with the predictions of a statistical model, the second is aligned along the velocity direction of the fissioning nuclei and has to be compared with the predictions of dynamical calculations. In this talk, we present the probability associated to each component as a function of the system size, the charge asymmetry of the fission fragments, the incident energy and the impact parameter. From the statistical component we extract the temperature, the charge and the angular momentum of the fissioning nuclei. From the second component we propose a scenario to explain such process and we discuss the physical parameters which can be extracted. (authors)

  3. Simulation of the Production Process Dynamics using Vensim and Stella

    National Research Council Canada - National Science Library

    Corina SBUGHEA

    2016-01-01

    .... For illustration, we chose a classic model of the dynamics of the production process, which we have implemented in Vensim and Stella, in order to obtain evolutionary trajectories of the endogenous...

  4. Catalytic Reactive Distillation for the Esterification Process: Experimental and Simulation

    Directory of Open Access Journals (Sweden)

    M. Mallaiah

    2017-10-01

    Full Text Available In the present study, methyl acetate has been synthesized using esterification of acetic acid with methanol in a continuous packed bed catalytic reactive distillation col- umn in the presence of novel Indion 180 ion exchange resin solid catalyst. The experiments were conducted at various operating conditions like reboiler temperature, reflux ratio, and different feed flow rates of the acetic acid and methanol. The non-ideal pseudo-homogeneous kinetic model has been developed for esterification of acetic acid with methanol in the presence of Indion 180 catalyst. The developed kinetic model was used for the simulation of the reactive distillation column for the synthesis of methyl acetate using equilibrium stage model in Aspen Plus version 7.3. The simulation results were compared with experimental results, and found that there is a good agreement between them. The sensitivity analyses were also carried out for the different parameters of bot- tom flow rate, feed temperatures of acetic acid and methanol, and feed flow rate of acetic acid and methanol.

  5. Post-processing interstitialcy diffusion from molecular dynamics simulations

    Science.gov (United States)

    Bhardwaj, U.; Bukkuru, S.; Warrier, M.

    2016-01-01

    An algorithm to rigorously trace the interstitialcy diffusion trajectory in crystals is developed. The algorithm incorporates unsupervised learning and graph optimization which obviate the need to input extra domain specific information depending on crystal or temperature of the simulation. The algorithm is implemented in a flexible framework as a post-processor to molecular dynamics (MD) simulations. We describe in detail the reduction of interstitialcy diffusion into known computational problems of unsupervised clustering and graph optimization. We also discuss the steps, computational efficiency and key components of the algorithm. Using the algorithm, thermal interstitialcy diffusion from low to near-melting point temperatures is studied. We encapsulate the algorithms in a modular framework with functionality to calculate diffusion coefficients, migration energies and other trajectory properties. The study validates the algorithm by establishing the conformity of output parameters with experimental values and provides detailed insights for the interstitialcy diffusion mechanism. The algorithm along with the help of supporting visualizations and analysis gives convincing details and a new approach to quantifying diffusion jumps, jump-lengths, time between jumps and to identify interstitials from lattice atoms.

  6. Post-processing interstitialcy diffusion from molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Bhardwaj, U., E-mail: haptork@gmail.com [Computational Analysis Division, BARC, Visakhapatnam, Andhra Pradesh, 530012 (India); Bukkuru, S. [Nuclear Physics Dept., Andhra University, Visakhapatnam, 530003 (India); Warrier, M. [Computational Analysis Division, BARC, Visakhapatnam, Andhra Pradesh, 530012 (India)

    2016-01-15

    An algorithm to rigorously trace the interstitialcy diffusion trajectory in crystals is developed. The algorithm incorporates unsupervised learning and graph optimization which obviate the need to input extra domain specific information depending on crystal or temperature of the simulation. The algorithm is implemented in a flexible framework as a post-processor to molecular dynamics (MD) simulations. We describe in detail the reduction of interstitialcy diffusion into known computational problems of unsupervised clustering and graph optimization. We also discuss the steps, computational efficiency and key components of the algorithm. Using the algorithm, thermal interstitialcy diffusion from low to near-melting point temperatures is studied. We encapsulate the algorithms in a modular framework with functionality to calculate diffusion coefficients, migration energies and other trajectory properties. The study validates the algorithm by establishing the conformity of output parameters with experimental values and provides detailed insights for the interstitialcy diffusion mechanism. The algorithm along with the help of supporting visualizations and analysis gives convincing details and a new approach to quantifying diffusion jumps, jump-lengths, time between jumps and to identify interstitials from lattice atoms. -- Graphical abstract:.

  7. 3D TCAD Simulation for Semiconductor Processes, Devices and Optoelectronics

    CERN Document Server

    Li, Simon

    2012-01-01

    Technology computer-aided design, or TCAD, is critical to today’s semiconductor technology and anybody working in this industry needs to know something about TCAD.  This book is about how to use computer software to manufacture and test virtually semiconductor devices in 3D.  It brings to life the topic of semiconductor device physics, with a hands-on, tutorial approach that de-emphasizes abstract physics and equations and emphasizes real practice and extensive illustrations.  Coverage includes a comprehensive library of devices, representing the state of the art technology, such as SuperJunction LDMOS, GaN LED devices, etc. Provides a vivid, internal view of semiconductor devices, through 3D TCAD simulation; Includes comprehensive coverage of  TCAD simulations for both optic and electronic devices, from nano-scale to high-voltage high-power devices; Presents material in a hands-on, tutorial fashion so that industry practitioners will find maximum utility; Includes a comprehensive library of devices, re...

  8. Fault-related dolomitization in the Orpesa Ranges (Iberian Chain, E Spain): reactive transport simulations and field data constraints

    Science.gov (United States)

    Gomez-Rivas, E.; Martin-Martin, J. D.; Corbella, M.; Teixell, A.

    2009-04-01

    The relationships between hydrothermal fluid circulation and fracturing that lead to mineral dissolution and/or precipitation in carbonate rocks have direct impacts on the evolution and final distribution of hydrocarbon reservoir permeability. Understanding the coupling between these processes is important for predicting permeability and improving hydrocarbon recovery. We present a case study of dolomitization processes in Cretaceous limestone from the Orpesa Ranges (Iberian Chain, E Spain). Extending over part of the Maestrat Cretaceous Basin, the Orpesa area is deformed by extensional faults. These faults accommodated thick sequences of shallow marine limestone, mainly during Aptian times. The syn-rift carbonates are partially dolomitized due to the circulation and mixing of hydrothermal fluids along normal faults and bedding. Both Aptian and later Neogene extensional faults must have served as conduits for the circulation of fluids. MVT deposits of Paleocene age are well documented in the Maestrat basin and may also be related to dolomitization. Samples of host rocks and vein fillings have been collected along strike and analyzed in different fault sections to characterize fluid and rock composition, track flow pathways and map the relationships of fluid flow with respect to the main normal faults in the area. Using field and geochemical data from the Orpesa Ranges carbonates, we have developed reactive-transport models to study the influence of different parameters in the dolomitization of carbonates related to the circulation and mixing of hydrothermal fluids at the outcrop scale. We present results from models that were run with constant and non-constant permeability. The main parameters analyzed include: initial porosity and permeability of layers and fractures, composition of fluids, groundwater and brines flux, composition of layers, reactive surface of minerals, differences in vertical and horizontal permeability, and presence or absence of stratigraphic

  9. Syllabic (~2-5 Hz) and fluctuation (~1-10 Hz) ranges in speech and auditory processing

    Science.gov (United States)

    Edwards, Erik; Chang, Edward F.

    2013-01-01

    Given recent interest in syllabic rates (~2-5 Hz) for speech processing, we review the perception of “fluctuation” range (~1-10 Hz) modulations during listening to speech and technical auditory stimuli (AM and FM tones and noises, and ripple sounds). We find evidence that the temporal modulation transfer function (TMTF) of human auditory perception is not simply low-pass in nature, but rather exhibits a peak in sensitivity in the syllabic range (~2-5 Hz). We also address human and animal neurophysiological evidence, and argue that this bandpass tuning arises at the thalamocortical level and is more associated with non-primary regions than primary regions of cortex. The bandpass rather than low-pass TMTF has implications for modeling auditory central physiology and speech processing: this implicates temporal contrast rather than simple temporal integration, with contrast enhancement for dynamic stimuli in the fluctuation range. PMID:24035819

  10. Hanford tank waste simulants specification and their applicability for the retrieval, pretreatment, and vitrification processes

    Energy Technology Data Exchange (ETDEWEB)

    GR Golcar; NG Colton; JG Darab; HD Smith

    2000-04-04

    A wide variety of waste simulants were developed over the past few years to test various retrieval, pretreatment and waste immobilization technologies and unit operations. Experiments can be performed cost-effectively using non-radioactive waste simulants in open laboratories. This document reviews the composition of many previously used waste simulants for remediation of tank wastes at the Hanford reservation. In this review, the simulants used in testing for the retrieval, pretreatment, and vitrification processes are compiled, and the representative chemical and physical characteristics of each simulant are specified. The retrieval and transport simulants may be useful for testing in-plant fluidic devices and in some cases for filtration technologies. The pretreatment simulants will be useful for filtration, Sr/TRU removal, and ion exchange testing. The vitrification simulants will be useful for testing melter, melter feed preparation technologies, and for waste form evaluations.

  11. Computational Simulation of VARI Fluid Process Molding for Stiffened Panel Structural Composites

    Directory of Open Access Journals (Sweden)

    XIAO Fei

    2016-08-01

    Full Text Available The resin filling time can be predicted and the flow pattern of resin can be simulated in Composites VARI Fluid Process Molding with simulation software PAM-RTM. The permeability is important parameter in VARI process. In-plane and transverse permeability are usually tested with complicate and expensive enclosed mold.A set of model with simple structure, easy operation, low cost, was built to obtain accurate permeability by using a process of vacuum-assisted resin infusion (VARI. Besides, the method of equivalent model was employed. The simulation results of effective model is compared with those of experimental VARI process. The filling times for simulation method is 254 s which is shorter than 301 s of the experimental process. Based on flow runner project with equivalent model, the stiffened panel structural composite is prepared to validate the selective process.

  12. A Strategy for Autogeneration of Space Shuttle Ground Processing Simulation Models for Project Makespan Estimations

    Science.gov (United States)

    Madden, Michael G.; Wyrick, Roberta; O'Neill, Dale E.

    2005-01-01

    Space Shuttle Processing is a complicated and highly variable project. The planning and scheduling problem, categorized as a Resource Constrained - Stochastic Project Scheduling Problem (RC-SPSP), has a great deal of variability in the Orbiter Processing Facility (OPF) process flow from one flight to the next. Simulation Modeling is a useful tool in estimation of the makespan of the overall process. However, simulation requires a model to be developed, which itself is a labor and time consuming effort. With such a dynamic process, often the model would potentially be out of synchronization with the actual process, limiting the applicability of the simulation answers in solving the actual estimation problem. Integration of TEAMS model enabling software with our existing schedule program software is the basis of our solution. This paper explains the approach used to develop an auto-generated simulation model from planning and schedule efforts and available data.

  13. Simulation and analysis of hot forging process for industrial locking gear elevators

    Science.gov (United States)

    Maarefdoust, M.; Kadkhodayan, M.

    2010-06-01

    In this paper hot forging process for industrial locking gear elevators is simulated and analyzed. An increase in demand of industrial locking gear elevators with better quality and lower price caused the machining process to be replaced by hot forging process. Production of industrial locking gear elevators by means of hot forging process is affected by many parameters such as billet temperature, geometry of die and geometry of pre-formatted billet. In this study the influences of billet temperature on effective plastic strain, radius of die corners on internal stress of billet and thickness of flash on required force of press are investigated by means of computer simulation. Three-dimensional modeling of initial material and die are performed by Solid Edge, while simulation and analysis of forging are performed by Super Forge. Based on the computer simulation the required dies are designed and the workpieces are formed. Comparison of simulation results with experimental data demonstrates great compatibility.

  14. Utilization of the Nursing Process to Foster Clinical Reasoning During a Simulation Experience

    Directory of Open Access Journals (Sweden)

    Amanda Lambie

    2015-11-01

    Full Text Available Nursing practice includes complex reasoning and multifaceted decision making with minimal standardized guidance in how to evaluate this phenomenon among nursing students. Learning outcomes related to the clinical reasoning process among novice baccalaureate nursing students during a simulation experience were evaluated. Nursing process records were utilized to evaluate and foster the development of clinical reasoning in a high-fidelity medical-surgical simulation experience. Students were unable to describe and process pertinent patient information appropriately prior to the simulation experience. Students’ ability to identify pertinent patient cues and plan appropriate patient care improved following the simulation. The learning activity afforded a structured opportunity to identify cues, prioritize the proper course of nursing interventions, and engage in collaboration among peers. The simulation experience provides faculty insight into the students’ clinical reasoning processes, while providing students with a clear framework for successfully accomplishing learning outcomes.

  15. Real-Time Simulation of Robot Controlled Belt Grinding Processes of Sculptured Surfaces

    Directory of Open Access Journals (Sweden)

    Xiang Zhang

    2004-06-01

    Full Text Available Industrial robots are introduced to belt grinding processes of free-formed surface with elastic wheel nowadays in order to obtain high quality product and high efficiency. However, it is a laborious task to plan grinding paths and write programs for the robot. To release people from it partially, it is necessary to simulate the belt grinding processes which are useful for path generating and dynamic robot control. In this paper, we present a framework of the robot controlled belt grinding simulation system and some key issues in it. We enhance the global removal model to local process model, which can simulate the grinding process more exactly. We also point out the bottleneck of the real-time simulation and put forward a neural network based regression method to meet this difficulty. At the end of the paper, some simple simulation examples are given.

  16. Improving the Aircraft Design Process Using Web-based Modeling and Simulation

    Science.gov (United States)

    Reed, John A.; Follen, Gregory J.; Afjeh, Abdollah A.

    2003-01-01

    Designing and developing new aircraft systems is time-consuming and expensive. Computational simulation is a promising means for reducing design cycle times, but requires a flexible software environment capable of integrating advanced multidisciplinary and muitifidelity analysis methods, dynamically managing data across heterogeneous computing platforms, and distributing computationally complex tasks. Web-based simulation, with its emphasis on collaborative composition of simulation models, distributed heterogeneous execution, and dynamic multimedia documentation, has the potential to meet these requirements. This paper outlines the current aircraft design process, highlighting its problems and complexities, and presents our vision of an aircraft design process using Web-based modeling and simulation.

  17. Improving the Aircraft Design Process Using Web-Based Modeling and Simulation

    Science.gov (United States)

    Reed, John A.; Follen, Gregory J.; Afjeh, Abdollah A.; Follen, Gregory J. (Technical Monitor)

    2000-01-01

    Designing and developing new aircraft systems is time-consuming and expensive. Computational simulation is a promising means for reducing design cycle times, but requires a flexible software environment capable of integrating advanced multidisciplinary and multifidelity analysis methods, dynamically managing data across heterogeneous computing platforms, and distributing computationally complex tasks. Web-based simulation, with its emphasis on collaborative composition of simulation models, distributed heterogeneous execution, and dynamic multimedia documentation, has the potential to meet these requirements. This paper outlines the current aircraft design process, highlighting its problems and complexities, and presents our vision of an aircraft design process using Web-based modeling and simulation.

  18. The use of process simulation models in virtual commissioning of process automation software in drinking water treatment plants

    NARCIS (Netherlands)

    Worm, G.I.M.; Kelderman, J.P.; Lapikas, T.; Van der Helm, A.W.C.; Van Schagen, K.M.; Rietveld, L.C.

    2012-01-01

    This research deals with the contribution of process simulation models to the factory acceptance test (FAT) of process automation (PA) software of drinking water treatment plants. Two test teams tested the same piece of modified PA-software. One team used an advanced virtual commissioning (AVC)

  19. Photonics-based real-time ultra-high-range-resolution radar with broadband signal generation and processing.

    Science.gov (United States)

    Zhang, Fangzheng; Guo, Qingshui; Pan, Shilong

    2017-10-23

    Real-time and high-resolution target detection is highly desirable in modern radar applications. Electronic techniques have encountered grave difficulties in the development of such radars, which strictly rely on a large instantaneous bandwidth. In this article, a photonics-based real-time high-range-resolution radar is proposed with optical generation and processing of broadband linear frequency modulation (LFM) signals. A broadband LFM signal is generated in the transmitter by photonic frequency quadrupling, and the received echo is de-chirped to a low frequency signal by photonic frequency mixing. The system can operate at a high frequency and a large bandwidth while enabling real-time processing by low-speed analog-to-digital conversion and digital signal processing. A conceptual radar is established. Real-time processing of an 8-GHz LFM signal is achieved with a sampling rate of 500 MSa/s. Accurate distance measurement is implemented with a maximum error of 4 mm within a range of ~3.5 meters. Detection of two targets is demonstrated with a range-resolution as high as 1.875 cm. We believe the proposed radar architecture is a reliable solution to overcome the limitations of current radar on operation bandwidth and processing speed, and it is hopefully to be used in future radars for real-time and high-resolution target detection and imaging.

  20. Students as Simulation Designers and Developers--Using Computer Simulations for Teaching Boundary Layer Processes.

    Science.gov (United States)

    Johnson, Tristan E.; Clayson, Carol Anne

    As technology developments seek to improve learning, researchers, developers, and educators seek to understand how technological properties impact performance. This paper delineates how a traditional science course is enhanced through the use of simulation projects directed by the students themselves as a means to increase their level of knowledge…

  1. Process simulation of a PEM fuel cell system

    Energy Technology Data Exchange (ETDEWEB)

    Ledjeff-Hey, K. [Gerhard-Mercator-Universitaet, Duisburg (Germany); Fraunhofer Inst. for Solar Energy Systems, Freiberg (Germany); Roes, J. [Gerhard-Mercator-Universitaet, Duisburg (Germany); Formanski, V. [Gerhard-Mercator-Universitaet, Duisburg (Germany); Gieshoff, J. [Fraunhofer Inst. for Solar Energy Systems, Freiberg (Germany); Vogel, B. [Fraunhofer Inst. for Solar Energy Systems, Freiberg (Germany)

    1996-01-01

    The thermodynamic performance of a PEM fuel cell system for producing electrical power from natural gas is investigated by considering the flows of energy and energy through the various steps of the whole system. The flows of energy are evaluated using a computer code for energy and energy analyses. The fuel cell system is designed to produce a hydrogen volumetric flow of nearly 5.0 m{sup 3} {sub NTP}/h, provided to the fuel cell at an absolute pressure of 2.9 bar. The fuel cell itself is working with an efficiency of about 60 % at an operating temperature of 65 - 75{degrees} C with an air ratio of four and provides a maximum electric power of 9 kW. Taking into consideration only the produced electric power as useful output of the fuel cell system a total efficiency of 42.2 % is calculated using the simulation results.

  2. Simulation of primary fuel atomization processes at subcritical pressures.

    Energy Technology Data Exchange (ETDEWEB)

    Arienti, Marco

    2013-06-01

    This report documents results from an LDRD project for the first-principles simulation of the early stages of spray formation (primary atomization). The first part describes a Cartesian embedded-wall method for the calculation of flow internal to a real injector in a fully coupled primary calculation. The second part describes the extension to an all-velocity formulation by introducing a momentum-conservative semi-Lagrangian advection and by adding a compressible term in the Poissons equation. Accompanying the description of the new algorithms are verification tests for simple two-phase problems in the presence of a solid interface; a validation study for a scaled-up multi-hole Diesel injector; and demonstration calculations for the closing and opening transients of a single-hole injector and for the high-pressure injection of liquid fuel at supersonic velocity.

  3. Ultrasonic-assisted manufacturing processes: Variational model and numerical simulations

    KAUST Repository

    Siddiq, Amir

    2012-04-01

    We present a computational study of ultrasonic assisted manufacturing processes including sheet metal forming, upsetting, and wire drawing. A fully variational porous plasticity model is modified to include ultrasonic softening effects and then utilized to account for instantaneous softening when ultrasonic energy is applied during deformation. Material model parameters are identified via inverse modeling, i.e. by using experimental data. The versatility and predictive ability of the model are demonstrated and the effect of ultrasonic intensity on the manufacturing process at hand is investigated and compared qualitatively with experimental results reported in the literature. © 2011 Elsevier B.V. All rights reserved.

  4. Ultrasonic-assisted manufacturing processes: variational model and numerical simulations.

    Science.gov (United States)

    Siddiq, Amir; El Sayed, Tamer

    2012-04-01

    We present a computational study of ultrasonic assisted manufacturing processes including sheet metal forming, upsetting, and wire drawing. A fully variational porous plasticity model is modified to include ultrasonic softening effects and then utilized to account for instantaneous softening when ultrasonic energy is applied during deformation. Material model parameters are identified via inverse modeling, i.e. by using experimental data. The versatility and predictive ability of the model are demonstrated and the effect of ultrasonic intensity on the manufacturing process at hand is investigated and compared qualitatively with experimental results reported in the literature. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. New method to simulate quantum interference using deterministic processes and application to event-based simulation of quantum computation

    NARCIS (Netherlands)

    De Raedt, H.; De Raedt, K.; Michielsen, K.

    2005-01-01

    We demonstrate that networks of locally connected processing units with a primitive learning capability exhibit behavior that is usually only attributed to quantum systems. We describe networks that simulate single-photon beam-splitter and Mach-Zehnder interferometer experiments on a causal,

  6. In-situ biogas upgrading process: modeling and simulations aspects

    DEFF Research Database (Denmark)

    Lovato, Giovanna; Alvarado-Morales, Merlin; Kovalovszki, Adam

    2017-01-01

    Biogas upgrading processes by in-situ hydrogen (H2) injection are still challenging and could benefit from a mathematical model to predict system performance. Therefore, a previous model on anaerobic digestion was updated and expanded to include the effect of H2 injection into the liquid phase of...

  7. Numerical simulation and parametric study of UOE pipe forming process

    Science.gov (United States)

    Ren, Qiang; Zou, Tian-xia; Ji, Zong-chen; Li, Da-yong; Peng, Ying-hong; Han, Jian-zeng; Wang, Xiao-xiu; Li, Xin-wen

    2013-05-01

    The UOE process is widely recognized as an effective approach to manufacture large-diameter submerged-arc welding pipes. During the UOE process, the plate is crimped along its edge, pressed into U and O shape, welded closed and then expanded to obtain a circular pipe. In this study, the mechanical properties tests are carried out on the API X80 pipeline steel to establish the constitutive model. A two-dimensional finite element model of the UOE forming process is established under plane strain assumption. The deformed geometry of different forming steps and the distribution of equivalent plastic strain are obtained. The model is validated in practical manufacturing by comparing the forming quality, which shows a significant coherence in their geometric configurations. In particular, the effect of process parameters on the forming quality is analyzed. Those parameters are the yield strength of the plate, the location of C-die, the initial location of U-rollers, the displacement of U-rollers, the location of V-anvil, the final spacing between O-punch and O-die. The main forming quality includes the opening after O-forming, the ovality after pre-welding and expansion. The relation curves of parameters versus forming quality are obtained and illustrated.

  8. Computer Simulation of Developmental Processes and Toxicities (SOT)

    Science.gov (United States)

    Rationale: Recent progress in systems toxicology and synthetic biology have paved the way to new thinking about in vitro/in silico modeling of developmental processes and toxicities, both for embryological and reproductive impacts. Novel in vitro platforms such as 3D organotypic ...

  9. Software for the Simulation of Power Plant Processes

    DEFF Research Database (Denmark)

    Elmegaard, Brian; Houbak, Niels

    2002-01-01

    Modelling of energy systems has been increasingly more important. In particular the dynamic behaviour is critical when operating the systems closer to the limits (either of the process, the materials, the emissions or the economics, etc.). This enforces strong requirements on both the models and ...

  10. Using Card Games to Simulate the Process of Natural Selection

    Science.gov (United States)

    Grilliot, Matthew E.; Harden, Siegfried

    2014-01-01

    In 1858, Darwin published "On the Origin of Species by Means of Natural Selection." His explanation of evolution by natural selection has become the unifying theme of biology. We have found that many students do not fully comprehend the process of evolution by natural selection. We discuss a few simple games that incorporate hands-on…

  11. Main reaction process simulation of hydrogen gas discharge in a ...

    Indian Academy of Sciences (India)

    2015-11-27

    Nov 27, 2015 ... ... reactions of hydrogen discharge in small electric vacuum components at low pressure and weak ionization were confirmed. Among the 21 types of reactions in hydrogen discharge process, 11 of them play importnat roles under low pressure and weak ionization in cold cathode electric vacuum device.

  12. Process-Play: A Simulation Procedure for Group Work Training.

    Science.gov (United States)

    Brenner, Viktor

    1999-01-01

    Describes process-play, an experiential training group structure that addresses the dilemma between participation in a training group and a student's right to privacy. Students participate in group training through a mask, whereby they differentially respond to certain group members on the basis of superficial characteristics. Introduces…

  13. Epidemic Processes on Complex Networks : Modelling, Simulation and Algorithms

    NARCIS (Netherlands)

    Van de Bovenkamp, R.

    2015-01-01

    Local interactions on a graph will lead to global dynamic behaviour. In this thesis we focus on two types of dynamic processes on graphs: the Susceptible-Infected-Susceptilbe (SIS) virus spreading model, and gossip style epidemic algorithms. The largest part of this thesis is devoted to the SIS

  14. Simulation of the perpendicular recording process including image charge effects

    NARCIS (Netherlands)

    Beusekamp, M.F.; Fluitman, J.H.J.

    1986-01-01

    This paper presents a complete model for the perpendicular recording process in single-pole-head keeper-layer configurations. It includes the influence of the image-charge distributions in the head and the keeper layer. Based on calculations of magnetization distributions in standstill situations,

  15. Simulation of Plant Physiological Process Using Fuzzy Variables

    Science.gov (United States)

    Daniel L. Schmoldt

    1991-01-01

    Qualitative modelling can help us understand and project effects of multiple stresses on trees. It is not practical to collect and correlate empirical data for all combinations of plant/environments and human/climate stresses, especially for mature trees in natural settings. Therefore, a mechanistic model was developed to describe ecophysiological processes. This model...

  16. Integration of life cycle assessment software with tools for economic and sustainability analyses and process simulation for sustainable process design

    DEFF Research Database (Denmark)

    Kalakul, Sawitree; Malakul, Pomthong; Siemanond, Kitipat

    2014-01-01

    The sustainable future of the world challenges engineers to develop chemical process designs that are not only technically and economically feasible but also environmental friendly. Life cycle assessment (LCA) is a tool for identifying and quantifying environmental impacts of the chemical product...... with other process design tools such as sustainable design (SustainPro), economic analysis (ECON) and process simulation. The software framework contains four main tools: Tool-I is for life cycle inventory (LCI) knowledge management that enables easy maintenance and future expansion of the LCI database; Tool...... and/or the process that makes it. It can be used in conjunction with process simulation and economic analysis tools to evaluate the design of any existing and/or new chemical-biochemical process and to propose improvement options in order to arrive at the best design among various alternatives...

  17. Temporal Gillespie Algorithm: Fast Simulation of Contagion Processes on Time-Varying Networks

    Science.gov (United States)

    Vestergaard, Christian L.; Génois, Mathieu

    2015-01-01

    Stochastic simulations are one of the cornerstones of the analysis of dynamical processes on complex networks, and are often the only accessible way to explore their behavior. The development of fast algorithms is paramount to allow large-scale simulations. The Gillespie algorithm can be used for fast simulation of stochastic processes, and variants of it have been applied to simulate dynamical processes on static networks. However, its adaptation to temporal networks remains non-trivial. We here present a temporal Gillespie algorithm that solves this problem. Our method is applicable to general Poisson (constant-rate) processes on temporal networks, stochastically exact, and up to multiple orders of magnitude faster than traditional simulation schemes based on rejection sampling. We also show how it can be extended to simulate non-Markovian processes. The algorithm is easily applicable in practice, and as an illustration we detail how to simulate both Poissonian and non-Markovian models of epidemic spreading. Namely, we provide pseudocode and its implementation in C++ for simulating the paradigmatic Susceptible-Infected-Susceptible and Susceptible-Infected-Recovered models and a Susceptible-Infected-Recovered model with non-constant recovery rates. For empirical networks, the temporal Gillespie algorithm is here typically from 10 to 100 times faster than rejection sampling. PMID:26517860

  18. Software and Process Developments in the Functionally Assembled Terrestrial Ecosystem Simulator (FATES)

    Science.gov (United States)

    Knox, R. G.; Koven, C.; Fisher, R.; Andre, B. J.; Bisht, G.; Vertenstein, M.; Riley, W. J.; Sacks, W.; Kluzek, E. B.; Lawrence, D. M.

    2016-12-01

    The Functionally Assembled Terrestrial Ecosystem Simulator (FATES) represents processes related to the demographics and dynamics of aboveground vegetation, often in an earth systems model context. It serves as a focal component of the Model-Experiment (MODEX) approach to the Next Generation Ecosystem Experiment (NGEE-Tropics). This is a tool to probe our understanding of the terrestrial carbon sink and forest response to a changing climate and human activities. It is co-developed with scientific measurement experiments that are designed specifically to improve our understanding of model process and parameterization. FATES is a successor of the Ecosystem Demography model, and had originally been coupled with the Community Land Model, ie CLM-ED. The work presented here describes refactoring to isolate the FATES code into a standalone module and create a well documented public API. The API allows FATES to be incorporated into a range of host models, such as the land models in ACME and CESM, and the ATS. Some newly developed model processes and testing strategies for verifying model results are presented as well.

  19. Contribution of muscle short-range stiffness to initial changes in joint kinetics and kinematics during perturbations to standing balance: A simulation study.

    Science.gov (United States)

    De Groote, Friedl; Allen, Jessica L; Ting, Lena H

    2017-04-11

    Simulating realistic musculoskeletal dynamics is critical to understanding neural control of muscle activity evoked in sensorimotor feedback responses that have inherent neural transmission delays. Thus, the initial mechanical response of muscles to perturbations in the absence of any change in muscle activity determines which corrective neural responses are required to stabilize body posture. Muscle short-range stiffness, a history-dependent property of muscle that causes a rapid and transient rise in muscle force upon stretch, likely affects musculoskeletal dynamics in the initial mechanical response to perturbations. Here we identified the contributions of short-range stiffness to joint torques and angles in the initial mechanical response to support surface translations using dynamic simulation. We developed a dynamic model of muscle short-range stiffness to augment a Hill-type muscle model. Our simulations show that short-range stiffness can provide stability against external perturbations during the neuromechanical response delay. Assuming constant muscle activation during the initial mechanical response, including muscle short-range stiffness was necessary to account for the rapid rise in experimental sagittal plane knee and hip joint torques that occurs simultaneously with very small changes in joint angles and reduced root mean square errors between simulated and experimental torques by 56% and 47%, respectively. Moreover, forward simulations lacking short-range stiffness produced unreasonably large joint angle changes during the initial response. Using muscle models accounting for short-range stiffness along with other aspects of history-dependent muscle dynamics may be important to advance our ability to simulate inherently unstable human movements based on principles of neural control and biomechanics. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. [CO2 response process and its simulation of Prunus sibirica photosynthesis under different soil moisture conditions].

    Science.gov (United States)

    Wu, Qin; Zhang, Guang-Can; Pei, Bin; Xu, Zhi-Qiang; Zhao, Yu; Fang, Li-Dong

    2013-06-01

    Taking the two-year old potted Prunus sibirica seedlings as test materials, and using CIRAS-2 photosynthetic system, this paper studied the CO2 response process of P. sibirica photosynthesis in semi-arid loess hilly region under eight soil moisture conditions. The CO2 response data of P. sibirica were fitted and analyzed by rectangular hyperbola model, exponential equation, and modified rectangular hyperbola model. Meanwhile, the quantitative relationships between the photosynthesis and the soil moisture were discussed. The results showed that the CO2 response process of P. sibirica photosynthesis had obvious response characteristics to the soil moisture threshold. The relative soil water content (RWC) required to maintain the higher photosynthetic rate (P(n)) and carboxylation efficiency (CE) of P. sibirica was in the range of 46.3%-81.9%. In this RWC range, the photosynthesis did not appear obvious CO2 saturated inhibition phenomenon. When the RWC exceeded this range, the photosynthetic capacity (P(n max)), CE, and CO2 saturation point (CSP) decreased evidently. Under different soil moisture conditions, there existed obvious differences among the three models in simulating the CO2 response data of P. sibirica. When the RWC was in the range of 46.3%-81.9%, the CO2 response process and the characteristic parameters such as CE, CO2 compensation point (see symbol), and photorespiration rate (R(p)) could be well fitted by the three models, and the accuracy was in the order of modified rectangular hyperbola model > exponential equation > rectangular hyperbola model. When the RWC was too high or too low, namely, the RWC was > 81.9% or process and the characteristic parameters. It was suggested that when the RWC was from 46.3% to 81.9%, the photosynthetic efficiency of P. sibirica was higher, and, as compared with rectangular hyperbola model and exponential equation, modified rectangular hyperbola model had more applicability to fit the CO2 response data of P. sibirica

  1. Simulation enabled search for explanatory mechanisms of the fracture healing process.

    Science.gov (United States)

    Kennedy, Ryan C; Marmor, Meir; Marcucio, Ralph; Hunt, C Anthony

    2018-02-01

    A significant portion of bone fractures fail to heal properly, increasing healthcare costs. Advances in fracture management have slowed because translation barriers have limited generation of mechanism-based explanations for the healing process. When uncertainties are numerous, analogical modeling can be an effective strategy for developing plausible explanations of complex phenomena. We demonstrate the feasibility of engineering analogical models in software to facilitate discovery of biomimetic explanations for how fracture healing may progress. Concrete analogical models-Callus Analogs-were created using the MASON simulation toolkit. We designated a Target Region initial state within a characteristic tissue section of mouse tibia fracture at day-7 and posited a corresponding day-10 Target Region final state. The goal was to discover a coarse-grain analog mechanism that would enable the discretized initial state to transform itself into the corresponding Target Region final state, thereby providing an alternative way to study the healing process. One of nine quasi-autonomous Tissue Unit types is assigned to each grid space, which maps to an 80×80 μm region of the tissue section. All Tissue Units have an opportunity each time step to act based on individualized logic, probabilities, and information about adjacent neighbors. Action causes transition from one Tissue Unit type to another, and simulation through several thousand time steps generates a coarse-grain analog-a theory-of the healing process. We prespecified a minimum measure of success: simulated and actual Target Region states achieve ≥ 70% Similarity. We used an iterative refinement protocol to explore many combinations of Tissue Unit logic and action constraints. Workflows progressed through four stages of analog mechanisms. Similarities of 73-90% were achieved for Mechanisms 2-4. The range of Upper-Level similarities increased to 83-94% when we allowed for uncertainty about two Tissue Unit

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

    Directory of Open Access Journals (Sweden)

    Wei Feng

    2015-01-01

    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.

  3. Challenges in simulation of chemical processes in combustion furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Hupa, M.; Kilpinen, P. [Aabo Akademi, Turku (Finland)

    1996-12-31

    The presentation gives an introduction to some of the present issues and problems in treating the complex chemical processes in combustion. The focus is in the coupling of the hydrocarbon combustion process with nitrogen oxide formation and destruction chemistry in practical furnaces or flames. Detailed kinetic modelling based on schemes of elementary reactions are shown to be a useful novel tool for identifying and studying the key reaction paths for nitrogen oxide formation and destruction in various systems. The great importance of the interaction between turbulent mixing and combustion chemistry is demonstrated by the sensitivity of both methane oxidation chemistry and fuel nitrogen conversion chemistry to the reactor and mixing pattern chosen for the kinetic calculations. The fluidized bed combustion (FBC) nitrogen chemistry involves several important heterogeneous reactions. Particularly the char in the bed plays an essential role. Recent research has advanced rapidly and the presentation proposes an overall picture of the fuel nitrogen reaction routes in circulating FBC conditions. (author)

  4. WHIZARD. Simulating multi-particle processes at LHC and ILC

    Energy Technology Data Exchange (ETDEWEB)

    Kilian, Wolfgang [Siegen Univ. (Germany). Theoretische Physik I; Ohl, Thorsten [Wuerzburg Univ. (Germany). Inst. fuer Theoretische Physik und Astrophysik; Reuter, Juergen [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Edinburgh Univ. (United Kingdom). School of Physics; Freiburg Univ. (Germany). Physikalisches Inst.

    2011-11-15

    We describe the universal Monte-Carlo (parton-level) event generator WHIZARD, version 2. The program automatically computes complete tree-level matrix elements, integrates them over phase space, evaluates distributions of observables, and generates unweighted partonic event samples. These are showered and hadronized by calling external codes, either automatically from within the program or via standard interfaces. There is no conceptual limit on the process complexity; using current hardware, the program has successfully been applied to hard scattering processes with up to eight particles in the final state. Matrix elements are computed as helicity amplitudes, so spin and color correlations are retained. For event generation, processes can be concatenated with full spin correlation, so factorized approximations to cascade decays are possible when complete matrix elements are not desired. The Standard Model, the MSSM, and many alternative models such as Little Higgs, anomalous couplings, or effects of extra dimensions or noncommutative SM extensions have been implemented. Using standard interfaces to parton shower and hadronization programs, WHIZARD covers physics at hadron, lepton, and photon colliders. (orig.)

  5. Universality and Realistic Extensions to the Semi-Analytic Simulation Principle in GNSS Signal Processing

    OpenAIRE

    O. Jakubov; P. Kacmarik; kovar, P.; F. Vejrazka

    2012-01-01

    Semi-analytic simulation principle in GNSS signal processing bypasses the bit-true operations at high sampling frequency. Instead, signals at the output branches of the integrate&dump blocks are successfully modeled, thus making extensive Monte Carlo simulations feasible. Methods for simulations of code and carrier tracking loops with BPSK, BOC signals have been introduced in the literature. Matlab toolboxes were designed and published. In this paper, we further extend the applicability o...

  6. Process Modelling Support for the Conceptual Modelling Phase of a Simulation Project

    OpenAIRE

    Heavey, Cathal; Ryan, John

    2006-01-01

    While many developments have taken place around supportingthe model coding task of simulation, there are few toolsavailable to assist in the conceptual modelling phase. Severalauthors have reported the advantages of using processmodelling tools in the early phases of a simulation project.This paper provides an overview of process modelling toolsin relation to their support for simulation, categorizing thetools into formal method and descriptive methods. A conclusionfrom this review is that no...

  7. Unified System for Processing Real and Simulated Data in the ATLAS Experiment

    CERN Document Server

    Borodin, Mikhail; De, Kaushik; Navarro, Jose Garcia; Golubkov, Dmitry; Klimentov, Alexei; Maeno, Tadashi; South, David; Vaniachine, Alexandre

    2015-01-01

    The physics goals of the next Large Hadron Collider run include high precision tests of the Standard Model and searches for new physics. These goals require detailed comparison of data with computational models simulating the expected data behavior. To highlight the role which modeling and simulation plays in future scientific discovery, we report on use cases and experience with a unified system built to process both real and simulated data of growing volume and variety.

  8. Analysis of the Utilization of Machinery in the Production Process Using Computer Simulation

    Directory of Open Access Journals (Sweden)

    Fedorko Gabriel

    2017-01-01

    Full Text Available For the efficient operation of each production process, individual machines and equipment must be used in the maximal possible measure. For this reason, it is necessary to know their utilization and to take measures to ensure their effective use. For performing such an analysis and to design subsequent measures, the use of the computer simulation method is very effective, e.g. simulation in Tecnomatix Plant Simulation program.

  9. Host Ranges of Listeria-Specific Bacteriophages from the Turkey Processing Plant Environment in the United States ▿

    Science.gov (United States)

    Kim, Jae-Won; Siletzky, Robin M.; Kathariou, Sophia

    2008-01-01

    Even though at least 400 Listeria phages have been isolated from various sources, limited information is available on phages from the food processing plant environment. Phages in the processing plant environment may play critical roles in determining the Listeria population that becomes established in the plant. In this study, we pursued the isolation of Listeria-specific phages from environmental samples from four turkey processing plants in the United States. These environmental samples were also utilized to isolate Listeria spp. Twelve phages were isolated and classified into three groups in terms of their host range. Of these, nine (group 1) showed a wide host range, including multiple serotypes of Listeria monocytogenes, as well as other Listeria spp. (L. innocua, L. welshimeri, L. seeligeri, and L. ivanovii). The remaining phages mostly infected L. monocytogenes serotype 4b as well as L. innocua, L. ivanovii, and/or L. welshimeri. All but one of the strains of the serotype 4b complex (4b, 4d, 4e) from the processing plant environment could be readily infected by the wide-host-range phages isolated from the environment of the processing plants. However, many strains of other serotypes (1/2a [or 3a] and 1/2b [or 3b]), which represented the majority of L. monocytogenes strains isolated from the environmental samples, were resistant to infection by these phages. Experiments with two phage-resistant strains showed reduced phage adsorption onto the host cells. These findings suggest that phage resistance may be an important component of the ecology of L. monocytogenes in the turkey processing plants. PMID:18791016

  10. Host ranges of Listeria-specific bacteriophages from the turkey processing plant environment in the United States.

    Science.gov (United States)

    Kim, Jae-Won; Siletzky, Robin M; Kathariou, Sophia

    2008-11-01

    Even though at least 400 Listeria phages have been isolated from various sources, limited information is available on phages from the food processing plant environment. Phages in the processing plant environment may play critical roles in determining the Listeria population that becomes established in the plant. In this study, we pursued the isolation of Listeria-specific phages from environmental samples from four turkey processing plants in the United States. These environmental samples were also utilized to isolate Listeria spp. Twelve phages were isolated and classified into three groups in terms of their host range. Of these, nine (group 1) showed a wide host range, including multiple serotypes of Listeria monocytogenes, as well as other Listeria spp. (L. innocua, L. welshimeri, L. seeligeri, and L. ivanovii). The remaining phages mostly infected L. monocytogenes serotype 4b as well as L. innocua, L. ivanovii, and/or L. welshimeri. All but one of the strains of the serotype 4b complex (4b, 4d, 4e) from the processing plant environment could be readily infected by the wide-host-range phages isolated from the environment of the processing plants. However, many strains of other serotypes (1/2a [or 3a] and 1/2b [or 3b]), which represented the majority of L. monocytogenes strains isolated from the environmental samples, were resistant to infection by these phages. Experiments with two phage-resistant strains showed reduced phage adsorption onto the host cells. These findings suggest that phage resistance may be an important component of the ecology of L. monocytogenes in the turkey processing plants.

  11. Simulationsverfahren fuer Brown-Resnick-Prozesse (Simulation Techniques for Brown-Resnick Processes)

    OpenAIRE

    Oesting, Marco

    2009-01-01

    Generalized Brown-Resnick processes form a flexible class of stationary max-stable processes based on Gaussian random fields. With regard to applications fast and accurate simulation of these processes is an important issue. In fact, Brown-Resnick processes that are generated by a dissipative flow do not allow for good finite approximations using the definition of the processes. On large intervals we get either huge approximation errors or very long operating times. Looking for solutions of t...

  12. Monte Carlo molecular simulation of phase-coexistence for oil production and processing

    KAUST Repository

    Li, Jun

    2011-01-01

    The Gibbs-NVT ensemble Monte Carlo method is used to simulate the liquid-vapor coexistence diagram and the simulation results of methane agree well with the experimental data in a wide range of temperatures. For systems with two components, the Gibbs-NPT ensemble Monte Carlo method is employed in the simulation while the mole fraction of each component in each phase is modeled as a Leonard-Jones fluid. As the results of Monte Carlo simulations usually contain huge statistical error, the blocking method is used to estimate the variance of the simulation results. Additionally, in order to improve the simulation efficiency, the step sizes of different trial moves is adjusted automatically so that their acceptance probabilities can approach to the preset values.

  13. Simulation of mass storage systems operating in a large data processing facility

    Science.gov (United States)

    Holmes, R.

    1972-01-01

    A mass storage simulation program was written to aid system designers in the design of a data processing facility. It acts as a tool for measuring the overall effect on the facility of on-line mass storage systems, and it provides the means of measuring and comparing the performance of competing mass storage systems. The performance of the simulation program is demonstrated.

  14. Students' Expectations of the Learning Process in Virtual Reality and Simulation-Based Learning Environments

    Science.gov (United States)

    Keskitalo, Tuulikki

    2012-01-01

    Expectations for simulations in healthcare education are high; however, little is known about healthcare students' expectations of the learning process in virtual reality (VR) and simulation-based learning environments (SBLEs). This research aims to describe first-year healthcare students' (N=97) expectations regarding teaching, studying, and…

  15. Ionic Liquid Design and Process Simulation for Decarbonization of Shale Gas

    DEFF Research Database (Denmark)

    Liu, Xinyan; Huang, Ying; Zhao, Yongsheng

    2016-01-01

    thermodynamic model was established. The simulation results have been found to agree well with the available experimental results. Two process flow sheet options, use of two single-stage flash operations or a multistage flash operation following the absorber, have been simulated and assessed. Compared...

  16. Anaerobic Digestion of Buffalo Dung: Simulation of Process Kinetics

    Directory of Open Access Journals (Sweden)

    Abdul Razaque Sahito

    2015-01-01

    Full Text Available Assessment of kinetic of AD (Anaerobic Digestion is a beneficial practice to forecast the performance of the process. It is helpful in the design of AD vessels, substrate feeding and digestate exit systems. The aim of this work was to assess the kinetics of anaerobically digested buffalo dung at different quantities of water added. It comprises the assessment of the specific methane production on the basis of VS (Volatile Solids added in each reactor by using three first order models, i.e. the modified Gompertz model, the Cone model and the Exponential Curve Factor model. The analysis was tested by using the three statistical parameters, i.e. the coefficient of multiple determinations, the standard deviation of residuals and the Akaike?s Information Criteria. The result reveals that the Exponential Curve Factor model was the best model that described the experimental data well. Moreover, there was not a direct or indirect relation between the kinetic coefficients of the AD process with the varying total or volatile solid content

  17. Simulation Of Assembly Processes With Technical Of Virtual Reality

    Science.gov (United States)

    García García, Manuel; Arenas Reina, José Manuel; Lite, Alberto Sánchez; Sebastián Pérez, Miguel Ángel

    2009-11-01

    Virtual reality techniques use at industrial processes provides a real approach to product life cycle. For components manual assembly, the use of virtual surroundings facilitates a simultaneous engineering in which variables such as human factors and productivity take a real act. On the other hand, in the actual phase of industrial competition it is required a rapid adjustment to client needs and to market situation. In this work it is analyzed the assembly of the front components of a vehicle using virtual reality tools and following up a product-process design methodology which includes every life service stage. This study is based on workstations design, taking into account productive and human factors from the ergonomic point of view implementing a postural study of every assembly operation, leaving the rest of stages for a later study. Design is optimized applying this methodology together with the use of virtual reality tools. It is also achieved a 15% reduction on time assembly and of 90% reduction in muscle—skeletal diseases at every assembly operation.

  18. PM(10) episodes in Greece: Local sources versus long-range transport-observations and model simulations.

    Science.gov (United States)

    Matthaios, Vasileios N; Triantafyllou, Athanasios G; Koutrakis, Petros

    2017-01-01

    Periods of abnormally high concentrations of atmospheric pollutants, defined as air pollution episodes, can cause adverse health effects. Southern European countries experience high particulate matter (PM) levels originating from local and distant sources. In this study, we investigated the occurrence and nature of extreme PM10 (PM with an aerodynamic diameter ≤10 μm) pollution episodes in Greece. We examined PM10 concentration data from 18 monitoring stations located at five sites across the country: (1) an industrial area in northwestern Greece (Western Macedonia Lignite Area, WMLA), which includes sources such as lignite mining operations and lignite power plants that generate a high percentage of the energy in Greece; (2) the greater Athens area, the most populated area of the country; and (3) Thessaloniki, (4) Patra, and (5) Volos, three large cities in Greece. We defined extreme PM10 pollution episodes (EEs) as days during which PM10 concentrations at all five sites exceeded the European Union (EU) 24-hr PM10 standards. For each EE, we identified the corresponding prevailing synoptic and local meteorological conditions, including wind surface data, for the period from January 2009 through December 2011. We also analyzed data from remote sensing and model simulations. We recorded 14 EEs that occurred over 49 days and could be grouped into two categories: (1) Local Source Impact (LSI; 26 days, 53%) and (2) African Dust Impact (ADI; 23 days, 47%). Our analysis suggested that the contribution of local sources to ADI EEs was relatively small. LSI EEs were observed only in the cold season, whereas ADI EEs occurred throughout the year, with a higher frequency during the cold season. The EEs with the highest intensity were recorded during African dust intrusions. ADI episodes were found to contribute more than local sources in Greece, with ADI and LSI fraction contribution ranging from 1.1 to 3.10. The EE contribution during ADI fluctuated from 41 to 83 μg/m3

  19. A Missing Data Approach to Correct for Direct and Indirect Range Restrictions with a Dichotomous Criterion: A Simulation Study

    National Research Council Canada - National Science Library

    Pfaffel, Andreas; Kollmayer, Marlene; Schober, Barbara; Spiel, Christiane

    2016-01-01

    ... only. This so-called range restriction problem causes biased population estimates. Correction methods for direct and indirect range restriction scenarios have widely studied for continuous criterion variables but not for dichotomous ones...

  20. Simulation of Wind Speed in the Ventilation Tunnel for Surge Tanks in Transient Processes

    National Research Council Canada - National Science Library

    Yang, Jiandong; Wang, Huang; Guo, Wencheng; Yang, Weijia; Zeng, Wei

    2016-01-01

    .... To obtain the wind speed in a ventilation tunnel for a surge tank during transient processes, this article adopts the one-dimensional numerical simulation method and establishes a mathematical model...

  1. Process Simulation of Resistance Weld Bonding and Automotive Light-weight Materials

    DEFF Research Database (Denmark)

    Zhang, Wenqi; Chergui, Azeddine; Nielsen, Chris Valentin

    This paper presents the latest developments in numerical simulation of resistance welding especially with the new functions for simulation of microstructures, weld bonding and spot welding of new light-weight materials. The fundamental functions in SORPAS® are built on coupled modeling...... of mechanical, electrical, thermal and metallurgical processes, which are essential for simulation of resistance welding process to predict the welding results and evaluate the weldability of materials. These functions have been further extended with new functions for optimization of welding process parameters...... and predicting welding process window, for weld planning with optimal welding parameter settings, and for modeling microstructures and hardness distribution after welding. Latest developments have been made on simulation of resistance welding with nonconductive materials for applications in weld bonding...

  2. The Detection of Shifts in Autocorrelated Processes with Moving Range and Exponentially-Weighted Moving Average Charts

    Directory of Open Access Journals (Sweden)

    Karin KANDANANOND

    2010-12-01

    Full Text Available The objective of this research is to select the appropriate control charts for detecting a shift in the autocorrelated observations. The autocorrelated processes were characterized using AR (1 and IMA (1, 1 for stationary and non-stationary processes respectively. A process model was simulated to achieve the response, the average run length (ARL. The empirical analysis was conducted to quantify the impacts of critical factors e.g., AR coefficient (f, MA coefficient (q, types of charts and shift sizes on the ARL. The results showed that the exponentially weighted moving average (EWMA was the most appropriate control chart to monitor AR (1 and IMA (1, 1 processes because of its sensitivity. For non-stationary case, the ARL at positive q was significantly higher than the one at negative q when a shift size was small. If the performance of the statistical process control under stationary and non-stationary disturbances is correctly characterized, practitioners will have guidelines for achieving the highest possible performance potential when deploying SPC.

  3. Design and fabrication of three-axis accelerometer sensor microsystem for wide temperature range applications using semi-custom process

    Science.gov (United States)

    Merdassi, A.; Wang, Y.; Xereas, G.; Chodavarapu, V. P.

    2014-03-01

    This paper describes an integrated CMOS-MEMS inertial sensor microsystem, consisting of a 3-axis accelerometer sensor device and its complementary readout circuit, which is designed to operate over a wide temperature range from - 55°C to 175°C. The accelerometer device is based on capacitive transduction and is fabricated using PolyMUMPS, which is a commercial process available from MEMSCAP. The fabricated accelerometer device is then post-processed by depositing a layer of amorphous silicon carbide to form a composite sensor structure to improve its performance over an extended wide temperature range. We designed and fabricated a CMOS readout circuit in IBM 0.13μm process that interfaces with the accelerometer device to serve as a capacitance to voltage converter. The accelerometer device is designed to operate over a measurement range of +/-20g. The described sensor system allows low power, low cost and mass-producible implementation well suited for a variety of applications with harsh or wide temperature operating conditions.

  4. Simulation of the surface roughness formation process in finishing

    Energy Technology Data Exchange (ETDEWEB)

    Losev, V.A.; Plyusnin, Y.G.

    1983-09-01

    Geometric, energy, and impulse models were developed to study the interaction of the abrasive and the ground surfaces in finishing. The geometric and energy models describe the process of finishing in the case of the use of tools with a fastened abrasive. The impulse model reflects the real picture of the action of unfastened abrasive grains on the surface being ground. The spectral density of the input signal is determined. The weight function and transfer function are treated. The spectral theory of the linear transformation of the stationary random function is used. On the basis of the experimental data and theoretical solutions, equations are obtained with which it is possible to predict the changes in surface roughness for various abrasive particle sizes.

  5. Mathematical Simulation of Porous Glass Thermal Processes at Annealing Stage

    Science.gov (United States)

    Grushko, I. S.

    2017-11-01

    The mathematical model of the porous glass heat field under conditions of complex heat exchange in the process of the technological stage of annealing is presented. The model includes calculations of the radiation, convective and molecular components. The mathematical model is based on the finite element method. The model is realised in the software Ansys. The statement of the problem is given. The object under study, i.e., model structural features, is presented. The method of model structure obtaining, the initials and boundary conditions are given. The theoretical basis of the methods, approaches and of the optimal calculation parameters choice principles are presented. The estimation of the model adequacy by means of the experimental verification is given. The comparison of the obtained data with the experimental results is performed. The relative error of calculation using the developed model does not exceed 15%.

  6. Tech-X Corporation releases simulation code for solving complex problems in plasma physics : VORPAL code provides a robust environment for simulating plasma processes in high-energy physics, IC fabrications and material processing applications

    CERN Multimedia

    2005-01-01

    Tech-X Corporation releases simulation code for solving complex problems in plasma physics : VORPAL code provides a robust environment for simulating plasma processes in high-energy physics, IC fabrications and material processing applications

  7. Multi-objective process optimisation of beer fermentation via dynamic simulation

    OpenAIRE

    Rodman, Alistair; Gerogiorgis, Dimitrios

    2016-01-01

    Fermentation is an essential step in beer brewing: when yeast is added to hopped wort, sugars released from the grain during germination are fermented into ethanol and higher alcohols. To study, simulate and optimise the beer fermentation process, accurate models of the chemical system are required for dynamic simulation of key component concentrations. Since the entire beer production process is a highly complex series of chemical reactions with the presence of over 600 species, many of the ...

  8. Simulations of the Ocean Response to a Hurricane: Nonlinear Processes

    KAUST Repository

    Zedler, Sarah E.

    2009-10-01

    Superinertial internal waves generated by a tropical cyclone can propagate vertically and laterally away from their local generation site and break, contributing to turbulent vertical mixing in the deep ocean and maintenance of the stratification of the main thermocline. In this paper, the results of a modeling study are reported to investigate the mechanism by which superinertial fluctuations are generated in the deep ocean. The general properties of the superinertial wave wake were also characterized as a function of storm speed and central latitude. The Massachusetts Institute of Technology (MIT) Ocean General Circulation Model (OGCM) was used to simulate the open ocean response to realistic westward-tracking hurricane-type surface wind stress and heat and net freshwater buoyancy forcing for regions representative of midlatitudes in the Atlantic, the Caribbean, and low latitudes in the eastern Pacific. The model had high horizontal [Δ(x, y) = 1/6°] and vertical (Δz = 5 m in top 100 m) resolution and employed a parameterization for vertical mixing induced by shear instability. In the horizontal momentum equation, the relative size of the nonlinear advection terms, which had a dominant frequency near twice the inertial, was large only in the upper 200 m of water. Below 200 m, the linear momentum equations obeyed a linear balance to 2%. Fluctuations at nearly twice the inertial frequency (2f) were prevalent throughout the depth of the water column, indicating that these nonlinear advection terms in the upper 200 m forced a linear mode below at nearly twice the inertial frequency via vorticity conservation. Maximum variance at 2f in horizontal velocity occurred on the south side of the track. This was in response to vertical advection of northward momentum, which in the north momentum equation is an oscillatory positive definite term that constituted a net force to the south at a frequency near 2f. The ratio of this term to the Coriolis force was larger on the

  9. Simulated hyperopic anisometropia and reading, visual information processing, and reading-related eye movement performance in children.

    Science.gov (United States)

    Narayanasamy, Sumithira; Vincent, Stephen J; Sampson, Geoff P; Wood, Joanne M

    2014-11-20

    This study investigated the impact of simulated hyperopic anisometropia and sustained near work on performance of academic-related measures in children. Participants included 16 children (mean age: 11.1 ± 0.8 years) with minimal refractive error. Academic-related outcome measures included a reading test (Neale Analysis of Reading Ability), visual information-processing tests (Coding and Symbol Search subtests from the Wechsler Intelligence Scale for Children), and a reading-related eye movement test (Developmental Eye Movement test). Performance was assessed with and without 0.75 diopters of simulated monocular hyperopic defocus (administered in a randomized order), before and after 20 minutes of sustained near work. Unilateral hyperopic defocus was systematically assigned to either the dominant or nondominant sighting eye to evaluate the impact of ocular dominance on any performance decrements. Simulated hyperopic anisometropia and sustained near work both independently reduced performance on all of the outcome measures (P anisometropia and near work (P anisometropia in combination with sustained near work. Laterality of the refractive error simulation (ocular dominance) did not significantly influence the outcome measures (P > 0.05). A reduction of up to 12% in performance was observed across the range of academic-related measures following sustained near work undertaken during the anisometropic simulation. Simulated hyperopic anisometropia significantly impaired academic-related performance, particularly in combination with sustained near work. The impact of uncorrected habitual anisometropia on academic-related performance in children requires further investigation. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  10. Stochastic Processes and Queueing Theory used in Cloud Computer Performance Simulations

    Directory of Open Access Journals (Sweden)

    Florin-Catalin ENACHE

    2015-10-01

    Full Text Available The growing character of the cloud business has manifested exponentially in the last 5 years. The capacity managers need to concentrate on a practical way to simulate the random demands a cloud infrastructure could face, even if there are not too many mathematical tools to simulate such demands.This paper presents an introduction into the most important stochastic processes and queueing theory concepts used for modeling computer performance. Moreover, it shows the cases where such concepts are applicable and when not, using clear programming examples on how to simulate a queue, and how to use and validate a simulation, when there are no mathematical concepts to back it up.

  11. Modelling and simulation of a pervaporation process using tubular module for production of anhydrous ethanol

    Science.gov (United States)

    Hieu, Nguyen Huu

    2017-09-01

    Pervaporation is a potential process for the final step of ethanol biofuel production. In this study, a mathematical model was developed based on the resistance-in-series model and a simulation was carried out using the specialized simulation software COMSOL Multiphysics to describe a tubular type pervaporation module with membranes for the dehydration of ethanol solution. The permeance of membranes, operating conditions, and feed conditions in the simulation were referred from experimental data reported previously in literature. Accordingly, the simulated temperature and density profiles of pure water and ethanol-water mixture were validated based on existing published data.

  12. Agent Behavior-Based Simulation Study on Mass Collaborative Product Development Process

    Directory of Open Access Journals (Sweden)

    Shuo Zhang

    2015-01-01

    Full Text Available Mass collaborative product development (MCPD benefits people by high innovation products with lower cost and shorter lead time due to quick development of group innovation, Internet-based customization, and prototype manufacturing. Simulation is an effective way to study the evolution process and therefore to guarantee the success of MCPD. In this paper, an agent behavior-based simulation approach of MCPD is developed, which models the MCPD process as the interactive process of design agents and the environment objects based on Complex Adaptive System (CAS theory. Next, the structure model of design agent is proposed, and the modification and collaboration behaviors are described. Third, the agent behavior-based simulation flow of MCPD is designed. At last, simulation experiments are carried out based on an engineering case of mobile phone design. The experiment results show the following: (1 the community scale has significant influence on MCPD process; (2 the simulation process can explicitly represent the modification and collaboration behaviors of design agents; (3 the community evolution process can be observed and analyzed dynamically based on simulation data.

  13. A framework of knowledge creation processes in participatory simulation of hospital work systems

    DEFF Research Database (Denmark)

    Andersen, Simone Nyholm; Broberg, Ole

    2017-01-01

    suggest applying a knowledge creation perspective. The aim of this study was to develop a framework describing the process of how ergonomics knowledge is created in PS. Video recordings from three projects applying PS of hospital work systems constituted the foundation of process mining analysis......Participatory simulation (PS) is a method to involve workers in simulating and designing their own future work system. Existing PS studies have focused on analysing the outcome, and minimal attention has been devoted to the process of creating this outcome. In order to study this process, we...

  14. Numerical Simulation of the Working Process in the Twin Screw Vacuum Pump

    Science.gov (United States)

    Lu, Yang; Fu, Yu; Guo, Bei; Fu, Lijuan; Zhang, Qingqing; Chen, Xiaole

    2017-08-01

    Twin screw vacuum pumps inherit the advantages of screw machinery, such as high reliability, stable medium conveying, small vibration, simple and compact structures, convenient operation, etc, which have been widely used in petrochemical and air industry. On the basis of previous studies, this study analyzed the geometric features of variable pitch of the twin screw vacuum pump such as the sealing line, the meshing line and the volume between teeth. The mathematical model of numerical simulation of the twin screw vacuum pump was established. The leakage paths of the working volume including the sealing line and the addendum arc were comprehensively considered. The corresponding simplified geometric model of leakage flow was built up for different leak paths and the flow coefficients were calculated. The flow coefficient value range of different leak paths was given. The results showed that the flow coefficient of different leak paths can be taken as constant value for the studied geometry. The analysis of recorded indicator diagrams showed that the increasing rotational speed can dramatically decrease the exhaust pressure and the lower rotational speed can lead to over-compression. The pressure of the isentropic process which was affected by leakage was higher than the theoretical process.

  15. A new multiscale modeling method for simulating the loss processes in polymer solar cell nanodevices.

    Science.gov (United States)

    Pershin, Anton; Donets, Sergii; Baeurle, Stephan A

    2012-05-21

    The photoelectric power conversion efficiency of polymer solar cells is till now, compared to conventional inorganic solar cells, still relatively low with maximum values ranging from 7% to 8%. This essentially relates to the existence of exciton and charge carrier loss phenomena, reducing the performance of polymer solar cells significantly. In this paper we introduce a new computer simulation technique, which permits to explore the causes of the occurrence of such phenomena at the nanoscale and to design new photovoltaic materials with optimized opto-electronic properties. Our approach consists in coupling a mesoscopic field-theoretic method with a suitable dynamic Monte Carlo algorithm, to model the elementary photovoltaic processes. Using this algorithm, we investigate the influence of structural characteristics and different device conditions on the exciton generation and charge transport efficiencies in case of a novel nanostructured polymer blend. More specifically, we find that the disjunction of continuous percolation paths leads to the creation of dead ends, resulting in charge carrier losses through charge recombination. Moreover, we observe that defects are characterized by a low exciton dissociation efficiency due to a high charge accumulation, counteracting the charge generation process. From these observations, we conclude that both the charge carrier loss and the exciton loss phenomena lead to a dramatic decrease in the internal quantum efficiency. Finally, by analyzing the photovoltaic behavior of the nanostructures under different circuit conditions, we demonstrate that charge injection significantly determines the impact of the defects on the solar cell performance.

  16. Experimental research and numerical simulation on cryogenic line chill-down process

    Science.gov (United States)

    Jin, Lingxue; Cho, Hyokjin; Lee, Cheonkyu; Jeong, Sangkwon

    2018-01-01

    The empirical heat transfer correlations are suggested for the fast cool down process of the cryogenic transfer line from room temperature to cryogenic temperature. The correlations include the heat transfer coefficient (HTC) correlations for single-phase gas convection and film boiling regimes, minimum heat flux (MHF) temperature, critical heat flux (CHF) temperature and CHF. The correlations are obtained from the experimental measurements. The experiments are conducted on a 12.7 mm outer diameter (OD), 1.25 mm wall thickness and 7 m long stainless steel horizontal pipe with liquid nitrogen (LN2). The effect of the lengthwise position is verified by measuring the temperature profiles in near the inlet and the outlet of the transfer line. The newly suggested heat transfer correlations are applied to the one-dimensional homogeneous transient model to simulate the cryogenic line chill-down process, and the chill-down time and the cryogen consumption are well predicted in the mass flux range from 26.0 kg/m2 s to 73.6 kg/m2 s through the correlations.

  17. Simulation of process for electrical energy production based on molten carbonate fuel cells

    Science.gov (United States)

    De Simon, G.; Parodi, F.; Fermeglia, M.; Taccani, R.

    A global molten carbonate fuel cells (MCFC) power plant steady-state simulation is presented. A performance fuel cell numerical model is developed and integrated as a custom block in Aspen plus™for the whole process simulation. The burner/reformer compact unit is built assembling existing Aspen plus™internal blocks. A simulation is obtained with the preliminary input specification to get to the base case and a sensitivity analysis is conducted, in order to find the process parameters whose change improves the global efficiency.

  18. Retrieval process development and enhancements project Fiscal year 1995: Simulant development technology task progress report

    Energy Technology Data Exchange (ETDEWEB)

    Golcar, G.R.; Bontha, J.R.; Darab, J.G. [and others

    1997-01-01

    The mission of the Retrieval Process Development and Enhancements (RPD&E) project is to develop an understanding of retrieval processes, including emerging and existing technologies, gather data on these technologies, and relate the data to specific tank problems such that end-users have the requisite technical bases to make retrieval and closure decisions. The development of waste simulants is an integral part of this effort. The work of the RPD&E simulant-development task is described in this document. The key FY95 accomplishments of the RPD&E simulant-development task are summarized below.

  19. Multivariant simulator for vacuum cooling processes of three component electrolyte systems

    Directory of Open Access Journals (Sweden)

    Suljkanović Midhat

    2010-01-01

    Full Text Available In this paper, a computer aided analysis and synthesis of the crystallization processes from multicomponent electrolyte systems were studied. In addition, the vacuum crystallization processes with adiabatic cooling of the system are presented. The cooling process of a multicomponent electrolyte system can be considered as a process with the concentration of the system and/or the crystallization of the solid phase from the system. Requirements for multivariant options of the process simulator are the result of practical needs in the design of new processes or the improvement of exploitation processes. According to this, there are needs for a simulation of a simple flashing of the system as well as for the vacuum cooling crystallization processes with the cyclic structure. The possibilities of the created process simulator are illustrated on three component electrolyte systems. Application of the process simulator for any other electrolyte systems requires only an update of the thermodynamic model, and physico-chemical properties related to electrolyte system.

  20. Exergetic analysis of cogeneration plants through integration of internal combustion engine and process simulators

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Leonardo de Oliveira [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil)], E-mail: leonardo.carvalho@petrobras.com.br; Leiroz, Albino Kalab; Cruz, Manuel Ernani [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), RJ (Brazil). Programa de Engenharia Mecanica], Emails: leiroz@mecanica.ufrj.br, manuel@mecanica.ufrj.br

    2010-07-01

    Internal combustion engines (ICEs) have been used in industry and power generation much before they were massively employed for transportation. Their high reliability, excellent power-to-weight ratio, and thermal efficiency have made them a competitive choice as main energy converters in small to medium sized power plants. Process simulators can model ICE powered energy plants with limited depth, due to the highly simplified ICE models used. Usually a better understanding of the global effects of different engine parameters is desirable, since the combustion process within the ICE is typically the main cause of exergy destruction in systems which utilize them. Dedicated commercial ICE simulators have reached such a degree of maturity, that they can adequately model a wide spectrum of phenomena that occur in ICEs. However, ICE simulators are unable to incorporate the remaining of power plant equipment and processes in their models. This paper presents and exploits the integration of an internal combustion engine simulator with a process simulator, so as to evaluate the construction of a fully coupled simulation platform to analyze the performance of ICE-based power plants. A simulation model of an actual cogeneration plant is used as a vehicle for application of the proposed computational methodology. The results show that by manipulating the engine mapping parameters, the overall efficiency of the plant can be improved. (author)

  1. Power plant simulators using Westinghouse distributed processing family hardware and software

    Energy Technology Data Exchange (ETDEWEB)

    Griebenow, R.; Sudduth, A.; Heuser, S.; Perdeus, M.; Fray, R.

    1993-10-01

    Duke Power Company and the Electric Power Research Institute have embarked on a joint effort to develop plant specific engineering and training simulators to support control replacement projects in Duke's fossil plants. These simulators use low cost personal computer hardware (PCs) and modular process simulation development software, integrated to Westinghouse Distributed Processing Family (WDPF) control hardware and software, to provide an accurate representation of the plant process and controls. Integrating the PC-based process simulation to the control system proved to be a very complex task. To meet the interface requirements, firmware was modified, and software and interface cards were developed that allow high-speed parallel access to the control system processor memory. In addition, modifications had to be made to provide necessary simulator training functions such as freezing the system, saving snap-shots, and loading initial conditions. This paper provides details on the development of the PC/WDPF interface and simulator instructor capabilities. In addition, it outlines plans for use of the simulator as an operator training and controls engineering tool.

  2. Computational Analysis and Simulation of Empathic Behaviors: a Survey of Empathy Modeling with Behavioral Signal Processing Framework.

    Science.gov (United States)

    Xiao, Bo; Imel, Zac E; Georgiou, Panayiotis; Atkins, David C; Narayanan, Shrikanth S

    2016-05-01

    Empathy is an important psychological process that facilitates human communication and interaction. Enhancement of empathy has profound significance in a range of applications. In this paper, we review emerging directions of research on computational analysis of empathy expression and perception as well as empathic interactions, including their simulation. We summarize the work on empathic expression analysis by the targeted signal modalities (e.g., text, audio, and facial expressions). We categorize empathy simulation studies into theory-based emotion space modeling or application-driven user and context modeling. We summarize challenges in computational study of empathy including conceptual framing and understanding of empathy, data availability, appropriate use and validation of machine learning techniques, and behavior signal processing. Finally, we propose a unified view of empathy computation and offer a series of open problems for future research.

  3. A Multiscale Simulation Framework to Investigate Hydrobiogeochemical Processes in the Groundwater-Surface Water Interaction Zone

    Science.gov (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.

    2016-12-01

    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

  4. On the performance of micro injection moulding process simulations of TPE micro rings

    DEFF Research Database (Denmark)

    Baruffi, Federico; Calaon, Matteo; Tosello, Guido

    Micro injection moulding (μIM) process simulations can be used as powerful tool for the optimization of the design of mould, parts and process. However, numerous combined scale effects introduce relevant challenges in terms of both validation and accuracy of the simulations [1], [2]. In this study......, a case study based on the micro injection moulding process of thermoplastic elastomer (TPE) micro rings (volume: 1.5 mm3, mass: 2.2 mg) for sensors application is treated. Injection moulding process simulations using Autodesk Moldflow Insight 2016® were applied with the aim of accomplishing two main...... tasks: the prediction of the main parts defects (weld lines and air traps) and of effects of the main injection moulding process parameters, namely mould temperature, melt temperature, injection speed and holding pressure, on the part geometrical accuracy. A three-dimensional multi-scale mesh...

  5. Ontological simulation for educational process organisation in a higher educational institution

    Science.gov (United States)

    Berestneva, O. G.; Marukhina, O. V.; Bahvalov, S. V.; Fisochenko, O. N.; Berestneva, E. V.

    2017-01-01

    Following the new-generation standards is needed to form a task list connected with planning and organizing of an academic process, structure and content formation of degree programmes. Even when planning the structure and content of an academic process, one meets some problems concerning the necessity to assess the correlation between degree programmes and demands of educational and professional standards and to consider today’s job-market and students demands. The paper presents examples of ontological simulations for solutions of organizing educational process problems in a higher educational institution and gives descriptions of model development. The article presents two examples: ontological simulation when planning an educational process in a higher educational institution and ontological simulation for describing competences of an IT-specialist. The paper sets a conclusion about ontology application perceptiveness for formalization of educational process organization in a higher educational institution.

  6. Stochastic simulation of nonstationary oscillation hydroclimatic processes using empirical mode decomposition

    Science.gov (United States)

    Lee, T.; Ouarda, T. B. M. J.

    2012-02-01

    Nonstationary oscillation (NSO) processes are observed in a number of hydroclimatic data series. Stochastic simulation models are useful to study the impacts of the climatic variations induced by NSO processes into hydroclimatic regimes. Reproducing NSO processes in a stochastic time series model is, however, a difficult task because of the complexity of the nonstationary behaviors. In the current study, a novel stochastic simulation technique that reproduces the NSO processes embedded in hydroclimatic data series is presented. The proposed model reproduces NSO processes by utilizing empirical mode decomposition (EMD) and nonparametric simulation techniques (i.e., k-nearest-neighbor resampling and block bootstrapping). The model was first tested with synthetic data sets from trigonometric functions and the Rössler system. The North Atlantic Oscillation (NAO) index was then examined as a real case study. This NAO index was then employed as an exogenous variable for the stochastic simulation of streamflows at the Romaine River in the province of Quebec, Canada. The results of the application to the synthetic data sets and the real-world case studies indicate that the proposed model preserves well the NSO processes along with the key statistical characteristics of the observations. It was concluded that the proposed model possesses a reasonable simulation capacity and a high potential as a stochastic model, especially for hydroclimatic data sets that embed NSO processes.

  7. An Interval-Valued Approach to Business Process Simulation Based on Genetic Algorithms and the BPMN

    Directory of Open Access Journals (Sweden)

    Mario G.C.A. Cimino

    2014-05-01

    Full Text Available Simulating organizational processes characterized by interacting human activities, resources, business rules and constraints, is a challenging task, because of the inherent uncertainty, inaccuracy, variability and dynamicity. With regard to this problem, currently available business process simulation (BPS methods and tools are unable to efficiently capture the process behavior along its lifecycle. In this paper, a novel approach of BPS is presented. To build and manage simulation models according to the proposed approach, a simulation system is designed, developed and tested on pilot scenarios, as well as on real-world processes. The proposed approach exploits interval-valued data to represent model parameters, in place of conventional single-valued or probability-valued parameters. Indeed, an interval-valued parameter is comprehensive; it is the easiest to understand and express and the simplest to process, among multi-valued representations. In order to compute the interval-valued output of the system, a genetic algorithm is used. The resulting process model allows forming mappings at different levels of detail and, therefore, at different model resolutions. The system has been developed as an extension of a publicly available simulation engine, based on the Business Process Model and Notation (BPMN standard.

  8. Simulation enables complex exhaust system production processes; Simulation ermoeglicht komplexe Fertigungsprozesse von Abgasanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Lanzinger, L. [Tecnomatix GmbH, Neu-Isenburg (Germany)

    2005-04-01

    Arvon-Meritor, a global supplier of car systems and components based in Augsburg, use the eM-Workplace software for exhaust system development. The software was developed by Tecnomatix, a leading provider of solutions for manufacturing process management. (orig.)

  9. Physical simulation of hot deformation and microstructural evolution of AISI 1016 steel using processing maps

    Energy Technology Data Exchange (ETDEWEB)

    Rajput, S.K. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Roorkee 247667 (India); Dikovits, M. [IWS—Institute for Materials Science and Welding, Graz University of Technology Kopernikusgasse 24, A-8010 Graz (Austria); Chaudhari, G.P., E-mail: chaudfmt@iitr.ernet.in [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Roorkee 247667 (India); Poletti, C. [IWS—Institute for Materials Science and Welding, Graz University of Technology Kopernikusgasse 24, A-8010 Graz (Austria); Warchomicka, F. [IWS—Institute for Materials Science and Welding, Graz University of Technology Kopernikusgasse 24, A-8010 Graz (Austria); IMST—Institute of Materials Science and Technology, Vienna University of Technology, Karlsplatz 13/E308, A-1040 Vienna (Austria); Pancholi, V.; Nath, S.K. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Roorkee 247667 (India)

    2013-12-10

    The hot deformation behavior of AISI 1016 steel is studied by performing hot compression tests in the Gleeble{sup ®} 3800 physical simulator in the temperature range 750–1050 °C after austenitization at 1050 °C for 5 min. The strain rates used vary from 0.01 to 80 s{sup −1} and the total true strain achieved is 0.7. The microstructural evolution is described based on light optical and scanning electron microscopy of the deformed and water quenched samples. An EBSD measurement on selected sample in the two-phase field is used to determine the microstructural changes in the ferritic phase. Then, processing windows are created using dynamic materials model, modified dynamic materials model, and strain rate sensitivity maps, which are correlated with the microstructural development. In order to determine the flow instability ranges produced by flow localization, different instability parameters are employed and compared. The processing map obtained using the power dissipation efficiency, η, correlates well with microstructural changes observed due to the dependency of this parameter on strain rate sensitivity m. Although instability zones predicted by the instability parameter κ{sub j} are similar to these predicted by flow localization parameter α, the latter approach is physically explained by the thermal softening due to adiabatic flow at high strain rates. Using sinh type constitutive equation, the average apparent activation energy for hot deformation of AISI 1016 steel is 290 kJ/mol and the stress exponent n is 3.8, indicating plastic deformation by dislocation gliding and climbing.

  10. Gate Design in Injection Molding of Microfluidic Components Using Process Simulations

    DEFF Research Database (Denmark)

    Marhöfer, David Maximilian; Tosello, Guido; Islam, Aminul

    2016-01-01

    Just as in conventional injection molding of plastics, process simulationsare an effective and interesting tool in the area of microinjection molding. They can be applied in order to optimize and assist the design of the microplastic part, the mold, and the actual process. Available simulation...... software is however actually made for macroscopic injection molding. By means of the correct implementation and careful modeling strategy though, it can also be applied to microplastic parts, as it is shown in the present work. Process simulations were applied to two microfluidic devices (amicrofluidic...... of this design in practiceas actual steel mold. Additionally, the simulation results were critically discussed and possible improvements and limitations of the gained results and the deployed software were described. Ultimately,the simulation results were validated by cross-checking the flow front behavior...

  11. Gate design in injection molding of microfluidic components using process simulations

    DEFF Research Database (Denmark)

    Marhöfer, D. M.; Tosello, G.; Islam, A.

    2015-01-01

    Just as in conventional injection molding of plastics, process simulations are an effective tool in the area of micro injection molding. They are applied in order to optimize and aid the design of the micro plastic part, the mold and the actual process. Available simulation software is actually...... made for macroscopic injection molding, but by means of the correct implementation and modelling strategy it can also be applied to micro plastic parts, as it is shown in the presented work. Process simulations are applied to two microfluidic devices (a micro distributor and a micro mixer) which shall...... be manufactured by micro injection molding. One of the main goals of the simulations is the investigation of the filling of the parts. Great emphasis is also on the optimization of selected gate designs for both parts which was successfully carried out. The paper describes how the two devices were meshed...

  12. A Simplified Finite Element Simulation for Straightening Process of Thin-Walled Tube

    Science.gov (United States)

    Zhang, Ziqian; Yang, Huilin

    2017-12-01

    The finite element simulation is an effective way for the study of thin-walled tube in the two cross rolls straightening process. To determine the accurate radius of curvature of the roll profile more efficiently, a simplified finite element model based on the technical parameters of an actual two cross roll straightening machine, was developed to simulate the complex straightening process. Then a dynamic simulation was carried out using ANSYS LS-DYNA program. The result implied that the simplified finite element model was reasonable for simulate the two cross rolls straightening process, and can be obtained the radius of curvature of the roll profile with the tube’s straightness 2 mm/m.

  13. Simulation of warpage induced by non-isothermal crystallization of co-polypropylene during the SLS process

    Science.gov (United States)

    Amado, Antonio; Schmid, Manfred; Wegener, Konrad

    2015-05-01

    Polymer processing using Additive Manufacturing Technologies (AM) has experienced a remarkable growth during the last years. The application range has been expanding rapidly, particularly driven by the so-called consumer 3D printing sector. However, for applications demanding higher requirements in terms of thermo-mechanical properties and dimensional accuracy the long established AM technologies such as Selective Laser Sintering (SLS) do not depict a comparable development. The higher process complexity hinders the number of materials that can be currently processed and the interactions between the different physics involved have not been fully investigated. In case of thermoplastic materials the crystallization kinetics coupled to the shrinkage strain development strongly influences the stability of the process. Thus, the current investigation presents a transient Finite Element simulation of the warpage effect during the SLS process of a new developed polyolefin (co-polypropylene) coupling the thermal, mechanical and phase change equations that control the process. A thermal characterization of the material was performed by means of DSC, integrating the Nakamura model with the classical Hoffmann-Lauritzen theory. The viscoelastic behavior was measured using a plate-plate rheometer at different degrees of undercooling and a phase change-temperature superposition principle was implemented. Additionally, for validation porpoises the warpage development of the first sintered layers was captured employing an optical device. The simulation results depict a good agreement with experimental measurements of deformation, describing the high sensitivity of the geometrical accuracy of the sintered parts related to the processing conditions.

  14. Measurements of ion cyclotron range of frequencies mode converted wave intensity with phase contrast imaging in Alcator C-Mod and comparison with full-wave simulations

    Energy Technology Data Exchange (ETDEWEB)

    Tsujii, N.; Porkolab, M.; Bonoli, P. T.; Lin, Y.; Wright, J. C.; Wukitch, S. J. [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Jaeger, E. F. [XCEL Engineering, Inc., Oak Ridge, Tennessee 37830 (United States); Green, D. L. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Harvey, R. W. [CompX, Del Mar, California 92014 (United States)

    2012-08-15

    Radio frequency waves in the ion cyclotron range of frequencies (ICRF) are widely used to heat tokamak plasmas. In ICRF heating schemes involving multiple ion species, the launched fast waves convert to ion cyclotron waves or ion Bernstein waves at the two-ion hybrid resonances. Mode converted waves are of interest as actuators to optimise plasma performance through current drive and flow drive. In order to describe these processes accurately in a realistic tokamak geometry, numerical simulations are essential, and it is important that these codes be validated against experiment. In this study, the mode converted waves were measured using a phase contrast imaging technique in D-H and D-{sup 3}He plasmas. The measured mode converted wave intensity in the D-{sup 3}He mode conversion regime was found to be a factor of {approx}50 weaker than the full-wave predictions. The discrepancy was reduced in the hydrogen minority heating regime, where mode conversion is weaker.

  15. All-digital signal-processing open-loop fiber-optic gyroscope with enlarged dynamic range.

    Science.gov (United States)

    Wang, Qin; Yang, Chuanchuan; Wang, Xinyue; Wang, Ziyu

    2013-12-15

    We propose and realize a new open-loop fiber-optic gyroscope (FOG) with an all-digital signal-processing (DSP) system where an all-digital phase-locked loop is employed for digital demodulation to eliminate the variation of the source intensity and suppress the bias drift. A Sagnac phase-shift tracking method is proposed to enlarge the dynamic range, and, with its aid, a new open-loop FOG, which can achieve a large dynamic range and high sensitivity at the same time, is realized. The experimental results show that compared with the conventional open-loop FOG with the same fiber coil and optical devices, the proposed FOG reduces the bias instability from 0.259 to 0.018 deg/h, and the angle random walk from 0.031 to 0.006 deg/h(1/2), moreover, enlarges the dynamic range to ±360 deg/s, exceeding the maximum dynamic range ±63 deg/s of the conventional open-loop FOG.

  16. The mid-domain effect matters: simulation analyses of range-size distribution data from Mount Kinabalu, Borneo

    DEFF Research Database (Denmark)

    Grytnes, John-Arvid; Beaman, John H.; Romdal, Tom Skovlund

    2008-01-01

    within the domain (range-restricted MDE), and a model encompassing all species with the theoretical midpoint within the domain (midpoint-restricted MDE). These predictions are compared with observations from the elevational pattern of range-size distributions and species richness of vascular plants...

  17. Impact of major and minor mode on EEG frequency range activities of music processing as a function of expertise.

    Science.gov (United States)

    Jenni, Raoul; Oechslin, Mathias S; James, Clara E

    2017-04-24

    Processing western tonal music may yield distinct brain responses depending on the mode of the musical compositions. Although subjective feelings in response to major and minor mode are well described, the underlying brain mechanisms and their development with increasing expertise have not been thoroughly examined. Using high-density electroencephalography, the present study investigated neuronal activities in the frequency domain in response to polyphone musical compositions in major and minor mode in non-musicians, amateurs and experts. During active listening decrease of theta- and gamma-frequency range activities occurred with increasing expertise in right posterior regions, possibly reflecting enhanced processing efficiency. Moreover, minor and major compositions distinctively modulated synchronization of neuronal activities in high frequency ranges (beta and gamma) in frontal regions, with increased activity in response to minor compositions in musicians and in experts in particular. These results suggest that high-frequency electroencephalographic (EEG) activities carry information about musical mode, showing gradual increase of processing efficiency and sensitivity with musical expertise. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. In-line process control for laser welding of titanium by high dynamic range ratio pyrometry and plasma spectroscopy

    Science.gov (United States)

    Lempe, B.; Taudt, C.; Baselt, T.; Rudek, F.; Maschke, R.; Basan, F.; Hartmann, P.

    2014-02-01

    The production of complex titanium components for various industries using laser welding processes has received growing attention in recent years. It is important to know whether the result of the cohesive joint meets the quality requirements of standardization and ultimately the customer requirements. Erroneous weld seams can have fatal consequences especially in the field of car manufacturing and medicine technology. To meet these requirements, a real-time process control system has been developed which determines the welding quality through a locally resolved temperature profile. By analyzing the resulting weld plasma received data is used to verify the stability of the laser welding process. The determination of the temperature profile is done by the detection of the emitted electromagnetic radiation from the material in a range of 500 nm to 1100 nm. As detectors, special high dynamic range CMOS cameras are used. As the emissivity of titanium depends on the wavelength, the surface and the angle of radiation, measuring the temperature is a problem. To solve these a special pyrometer setting with two cameras is used. That enables the compensation of these effects by calculating the difference between the respective pixels on simultaneously recorded images. Two spectral regions with the same emissivity are detected. Therefore the degree of emission and surface effects are compensated and canceled out of the calculation. Using the spatially resolved temperature distribution the weld geometry can be determined and the laser process can be controlled. The active readjustment of parameters such as laser power, feed rate and inert gas injection increases the quality of the welding process and decreases the number of defective goods.

  19. Shell model based reaction rates for rp-process nuclei in the mass range A=44-63

    CERN Document Server

    Fisker, J L; Görres, J; Langanke, K; Martínez-Pinedo, G; Wiescher, M C

    2001-01-01

    We have used large-scale shell-model diagonalization calculations to determine the level spectra, proton spectroscopic factors, and electromagnetic transition probabilities for proton rich nuclei in the mass range A=44-63. Based on these results and the available experimental data, we calculated the resonances for proton capture reactions on neutron deficient nuclei in this mass range. We also calculated the direct capture processes on these nuclei in the framework of a Woods-Saxon potential model. Taking into account both resonant and direct contributions, we determined the ground-state proton capture reaction rates for these nuclei under hot hydrogen burning conditions for temperatures between 10 sup 8 and 10 sup 1 sup 0 K. The calculated compound-nucleus level properties and the reaction rates are presented here; the rates are also available in computer-readable format from the authors.

  20. A low-noise SQUID simulator with a large dynamic range of up to eight flux quanta

    NARCIS (Netherlands)

    Martinez, A.; Flokstra, Jakob; Rillo, C.; Angurel, L.A.; Garcia, L.M.; ter Brake, Hermanus J.M.

    1990-01-01

    A 19 channel d.c. SQUID magnetometer for biomagnetic research is under construction. The system needs compactly built control and detection electronics and to facilitate the test an electronic circuit simulating the typical periodic characteristics of a SQUID was developed. In total nine steps of

  1. Possibilities and importance of using computer games and simulations in educational process

    Directory of Open Access Journals (Sweden)

    Danilović Mirčeta S.

    2003-01-01

    Full Text Available The paper discusses if it is possible and appropriate to use simulations (simulation games and traditional games in the process of education. It is stressed that the terms "game" and "simulation" can and should be taken in a broader sense, although they are chiefly investigated herein as video-computer games and simulations. Any activity combining the properties of game (competition, rules, players and the properties of simulation (i.e. operational presentation of reality should be understood as simulation games, where role-play constitutes their essence and basis. In those games the student assumes a new identity, identifies himself with another personality and responds similarly. Game rules are basic and most important conditions for its existence, accomplishment and goal achievement. Games and simulations make possible for a student to acquire experience and practice i.e. to do exercises in nearly similar or identical life situations, to develop cognitive and psycho-motor abilities and skills, to acquire knowledge, to develop, create and change attitudes and value criteria, and to develop perception of other people’s feelings and attitudes. It is obligatory for the teacher to conduct preparations to use and apply simulation games in the process of teaching.

  2. The use of discrete-event simulation modelling to improve radiation therapy planning processes.

    Science.gov (United States)

    Werker, Greg; Sauré, Antoine; French, John; Shechter, Steven

    2009-07-01

    The planning portion of the radiation therapy treatment process at the British Columbia Cancer Agency is efficient but nevertheless contains room for improvement. The purpose of this study is to show how a discrete-event simulation (DES) model can be used to represent this complex process and to suggest improvements that may reduce the planning time and ultimately reduce overall waiting times. A simulation model of the radiation therapy (RT) planning process was constructed using the Arena simulation software, representing the complexities of the system. Several types of inputs feed into the model; these inputs come from historical data, a staff survey, and interviews with planners. The simulation model was validated against historical data and then used to test various scenarios to identify and quantify potential improvements to the RT planning process. Simulation modelling is an attractive tool for describing complex systems, and can be used to identify improvements to the processes involved. It is possible to use this technique in the area of radiation therapy planning with the intent of reducing process times and subsequent delays for patient treatment. In this particular system, reducing the variability and length of oncologist-related delays contributes most to improving the planning time.

  3. A framework of knowledge creation processes in participatory simulation of hospital work systems.

    Science.gov (United States)

    Andersen, Simone Nyholm; Broberg, Ole

    2017-04-01

    Participatory simulation (PS) is a method to involve workers in simulating and designing their own future work system. Existing PS studies have focused on analysing the outcome, and minimal attention has been devoted to the process of creating this outcome. In order to study this process, we suggest applying a knowledge creation perspective. The aim of this study was to develop a framework describing the process of how ergonomics knowledge is created in PS. Video recordings from three projects applying PS of hospital work systems constituted the foundation of process mining analysis. The analysis resulted in a framework revealing the sources of ergonomics knowledge creation as sequential relationships between the activities of simulation participants sharing work experiences; experimenting with scenarios; and reflecting on ergonomics consequences. We argue that this framework reveals the hidden steps of PS that are essential when planning and facilitating PS that aims at designing work systems. Practitioner Summary: When facilitating participatory simulation (PS) in work system design, achieving an understanding of the PS process is essential. By applying a knowledge creation perspective and process mining, we investigated the knowledge-creating activities constituting the PS process. The analysis resulted in a framework of the knowledge-creating process in PS.

  4. Teaching Business Process Management with Simulation in Graduate Business Programs: An Integrative Approach

    Science.gov (United States)

    Saraswat, Satya Prakash; Anderson, Dennis M.; Chircu, Alina M.

    2014-01-01

    This paper describes the development and evaluation of a graduate level Business Process Management (BPM) course with process modeling and simulation as its integral component, being offered at an accredited business university in the Northeastern U.S. Our approach is similar to that found in other Information Systems (IS) education papers, and…

  5. Modeling and simulation of offshore wind farm O&M processes

    Energy Technology Data Exchange (ETDEWEB)

    Joschko, Philip, E-mail: joschko@informatik.uni-hamburg.de [University of Hamburg, Dept. of Informatics, Vogt-Kölln-Straße 30, 22527 Hamburg (Germany); Widok, Andi H., E-mail: a.widok@htw-berlin.de [University of Hamburg, Dept. of Informatics, Vogt-Kölln-Straße 30, 22527 Hamburg (Germany); Appel, Susanne, E-mail: susanne.appel@hs-bremen.de [HSB Bremen, Institute for Environment and Biotechnology, Neustadtswall 30, 28199 Bremen (Germany); Greiner, Saskia, E-mail: saskia.greiner@hs-bremen.de [HSB Bremen, Institute for Environment and Biotechnology, Neustadtswall 30, 28199 Bremen (Germany); Albers, Henning, E-mail: henning.albers@hs-bremen.de [HSB Bremen, Institute for Environment and Biotechnology, Neustadtswall 30, 28199 Bremen (Germany); Page, Bernd, E-mail: page@informatik.uni-hamburg.de [University of Hamburg, Dept. of Informatics, Vogt-Kölln-Straße 30, 22527 Hamburg (Germany)

    2015-04-15

    This paper describes a holistic approach to operation and maintenance (O&M) processes in the domain of offshore wind farm power generation. The acquisition and process visualization is followed by a risk analysis of all relevant processes. Hereafter, a tool was designed, which is able to model the defined processes in a BPMN 2.0 notation, as well as connect and simulate them. Furthermore, the notation was enriched with new elements, representing other relevant factors that were, to date, only displayable with much higher effort. In that regard a variety of more complex situations were integrated, such as for example new process interactions depending on different weather influences, in which case a stochastic weather generator was combined with the business simulation or other wind farm aspects important to the smooth running of the offshore wind farms. In addition, the choices for different methodologies, such as the simulation framework or the business process notation will be presented and elaborated depending on the impact they had on the development of the approach and the software solution. - Highlights: • Analysis of operation and maintenance processes of offshore wind farms • Process modeling with BPMN 2.0 • Domain-specific simulation tool.

  6. Prediction of acoustic foam properties by numerical simulation of polyurethane foaming process

    Directory of Open Access Journals (Sweden)

    Abdessalam Hichem

    2016-01-01

    Full Text Available This work aims to model and to simulate the polyurethane foaming process. Models taking into account the two main chemical reactions of the formation of polyurethane, the exothermic effect of these reactions as well as the thermo-rheo-kinetic coupling characterizing this process are proposed and implemented in the software NOGRID-points based on a meshless method (Finite Pointset Method. A prediction of some acoustic foam characteristics is also proposed based on the results of the numerical simulation of the foaming process and semi-phenomenological models.

  7. Application of a concept development process to evaluate process layout designs using value stream mapping and simulation

    Directory of Open Access Journals (Sweden)

    Ki-Young Jeong

    2011-07-01

    Full Text Available Purpose: We propose and demonstrate a concept development process (CDP as a framework to solve a value stream mapping (VSM related process layout design optimization problem.Design/methodology/approach: A case study approach was used to demonstrate the effectiveness of CDP framework in a portable fire extinguisher manufacturing company. To facilitate the CDP application, we proposed the system coupling level index (SCLI and simulation to evaluate the process layout design concepts.Findings: As part of the CDP framework application, three process layout design concepts - current layout (CL, express lane layout (ELL and independent zone layout (IZL - were generated. Then, the SCLI excluded CL and simulation selected IZL as the best concept. The simulation was also applied to optimize the performance of IZL in terms of the number of pallets. Based on this case study, we concluded that CDP framework worked well.Research limitations/implications: The process layout design optimization issue has not been well addressed in the VSM literature. We believe that this paper initiated the relevant discussion by showing the feasibility of CDP as a framework in this issue.Practical implications: The CDP and SCLI are very practice-oriented approaches in the sense that they do not require any complex analytical knowledge.Originality/value: We discussed a not well-addressed issue with a systematic framework. In addition, the SCLI presented was also unique.

  8. Comparative analysis of different process simulation settings of a micro injection molded part featuring conformal cooling

    DEFF Research Database (Denmark)

    Marhöfer, David Maximilian; Tosello, Guido; Islam, Aminul

    2015-01-01

    Process simulations are applied in all fields of engineering in order to support and optimize the design and quality of products and their manufacturing processes. Micro injection molding is not an exception in this regard. Simulations enable to investigate the process and the part quality....... In the reported work, process simulations using Autodesk Moldflow Insight 2015® are applied to a micro mechanical part to be fabricated by micro injection molding and with over-all dimensions of 12.0 × 3.0 × 0.8 mm³ and micro features (micro hole, diameter of 580 μm, and sharp radii down to 100 μm). Three...... of the implementation of the actual mold block, conventional cooling, and conformal cooling. In the comparison, characteristic quality criteria for injection molding are studied, such as the filling behavior of the cavity, the injection pressure, the temperature distribution, and the resulting part warpage...

  9. Numerical simulation and parameter optimization of automobile reinforced inner plate forming process

    Science.gov (United States)

    Su, Yanhong; Ma, Yaxin; Men, Zhengxing; Tang, Yue; Wang, Menghan

    2017-08-01

    Automotive reinforced inner plate is a typical sheet metal stamping parts, which is characterized by complex shape, the need for multi-channel process to complete. If the parts can be based on the needs and possibilities of a reasonable combination of some processes, not only can improve the quality of the workpiece, but also can save mold costs and improve production efficiency. The finite element analysis software Dy naform is used to develop the finite element model, and the forming process of the automotive reinforced inner plate was simulated and analyzed. The process parameters influencing the forming quality were optimized, and the shape and size of the blank were optimized to obtain the ideal billet state. In the wrinkled surface on the local optimization, a good control of the product forming quality. Finally, the simulation results are compared with those of the actual production. The correctness of the numerical simulation is verified.

  10. [Research on the range of motion measurement system for spine based on LabVIEW image processing technology].

    Science.gov (United States)

    Li, Xiaofang; Deng, Linhong; Lu, Hu; He, Bin

    2014-08-01

    A measurement system based on the image processing technology and developed by LabVIEW was designed to quickly obtain the range of motion (ROM) of spine. NI-Vision module was used to pre-process the original images and calculate the angles of marked needles in order to get ROM data. Six human cadaveric thoracic spine segments T7-T10 were selected to carry out 6 kinds of loads, including left/right lateral bending, flexion, extension, cis/counterclockwise torsion. The system was used to measure the ROM of segment T8-T9 under the loads from 1 Nm to 5 Nm. The experimental results showed that the system is able to measure the ROM of the spine accurately and quickly, which provides a simple and reliable tool for spine biomechanics investigators.

  11. The Pasm Parallel Processing System: Design, Simulation, and Image Processing Applications. Volume 1

    Science.gov (United States)

    1989-12-31

    communicate synchronizing instructions to the PEs. An additional MC-PE Communicatio .: Bus is used in both SIMD and MLMD modes. Individual PEs use the...6) disk file 1/O; (7) inter-process communication; and (8) frame and internet level communication. Process management includes the following...formed. The packet header indicates the process id that is to receive the message. the packet is then prefixed with an internet header specifying the

  12. Application of high-temperature simulated distillation to the residuum oil supercritical extraction process in petroleum refining

    Science.gov (United States)

    Raia; Villalanti; Subramanian; Williams

    2000-01-01

    The gas chromatographic method of high-temperature simulated distillation (HTSD) is described, and the results are presented for the application of HTSD to the characterization of petroleum refinery feed and products from solvent deasphalting operations. Results are presented for refinery residual feed, deasphalted oil, and asphaltene fractions from the residual oil supercritical extraction process. Asphaltene removal from petroleum residuum using solvent deasphalting results in the improved quality and high recovery of deasphalted oil product for use as lube oil, fluid catalytic cracking, or hydrocracker feedstocks. The HTSD procedure presented here proves valuable for characterizing the fractions from the deasphalting process to obtain the percentage yield with boiling point data over the range from approximately 36 degrees C (97 degrees F) to 733 degrees C (1352 degrees F), which covers the boiling range of n-paraffins of carbon number C5 to C108.

  13. Evaluation of Surface Runoff Generation Processes Using a Rainfall Simulator: A Small Scale Laboratory Experiment

    Science.gov (United States)

    Danáčová, Michaela; Valent, Peter; Výleta, Roman

    2017-12-01

    Nowadays, rainfall simulators are being used by many researchers in field or laboratory experiments. The main objective of most of these experiments is to better understand the underlying runoff generation processes, and to use the results in the process of calibration and validation of hydrological models. Many research groups have assembled their own rainfall simulators, which comply with their understanding of rainfall processes, and the requirements of their experiments. Most often, the existing rainfall simulators differ mainly in the size of the irrigated area, and the way they generate rain drops. They can be characterized by the accuracy, with which they produce a rainfall of a given intensity, the size of the irrigated area, and the rain drop generating mechanism. Rainfall simulation experiments can provide valuable information about the genesis of surface runoff, infiltration of water into soil and rainfall erodibility. Apart from the impact of physical properties of soil, its moisture and compaction on the generation of surface runoff and the amount of eroded particles, some studies also investigate the impact of vegetation cover of the whole area of interest. In this study, the rainfall simulator was used to simulate the impact of the slope gradient of the irrigated area on the amount of generated runoff and sediment yield. In order to eliminate the impact of external factors and to improve the reproducibility of the initial conditions, the experiments were conducted in laboratory conditions. The laboratory experiments were carried out using a commercial rainfall simulator, which was connected to an external peristaltic pump. The pump maintained a constant and adjustable inflow of water, which enabled to overcome the maximum volume of simulated precipitation of 2.3 l, given by the construction of the rainfall simulator, while maintaining constant characteristics of the simulated precipitation. In this study a 12-minute rainfall with a constant intensity

  14. Resistance Upset Welding of ODS Steel Fuel Claddings—Evaluation of a Process Parameter Range Based on Metallurgical Observations

    Directory of Open Access Journals (Sweden)

    Fabien Corpace

    2017-08-01

    Full Text Available Resistance upset welding is successfully applied to Oxide Dispersion Strengthened (ODS steel fuel cladding. Due to the strong correlation between the mechanical properties and the microstructure of the ODS steel, this study focuses on the consequences of the welding process on the metallurgical state of the PM2000 ODS steel. A range of process parameters is identified to achieve operative welding. Characterizations of the microstructure are correlated to measurements recorded during the welding process. The thinness of the clad is responsible for a thermal unbalance, leading to a higher temperature reached. Its deformation is important and may lead to a lack of joining between the faying surfaces located on the outer part of the join which can be avoided by increasing the dissipated energy or by limiting the clad stick-out. The deformation and the temperature reached trigger a recrystallization phenomenon in the welded area, usually combined with a modification of the yttrium dispersion, i.e., oxide dispersion, which can damage the long-life resistance of the fuel cladding. The process parameters are optimized to limit the deformation of the clad, preventing the compactness defect and the modification of the nanoscale oxide dispersion.

  15. Teaching Process Simulation in Eleven Easy Lessons Using Excel and Its Tools

    Science.gov (United States)

    Morris, Arthur E.

    The primary market driver for improving process technology is innovation, which requires a skilled and educated workforce. However, many Materials Science and Engineering departments have eliminated extractive metallurgy and chemical thermodynamics from their curricula, yet these topics contain the necessary fundamentals for process innovation. As a result, most MS&E students are ill-prepared for careers in processing. The dearth of process-oriented MS&E curricula has prompted some Universities to develop a "shared" effort to offer distance education between multiple institutions [1]. A target audience for a shared process simulation course would not only benefit students, but also be a basis for an on-line course for practicing engineers faced with new or changing career choices. To fill the gap, the basics of a process simulation course was developed in an abbreviated form as series of eleven articles and Excel workbooks published in Industrial Heating magazine between July 2012 and July 2013.

  16. Redesigning business processes : a methodology based on simulation and process mining techniques

    NARCIS (Netherlands)

    Maruster, L.; van Beest, N.R.T.P.

    2009-01-01

    Nowadays, organizations have to adjust their business processes along with the changing environment in order to maintain a competitive advantage. Changing a part of the system to support the business process implies changing the entire system, which leads to complex redesign activities. In this

  17. Development of simulator for studying formation process of crustal structure. 1; Chikaku kozo keisei simulator no kaihatsu. 1

    Energy Technology Data Exchange (ETDEWEB)

    Matsushima, J. [The University of Tokyo, Tokyo (Japan). Faculty of Engineering; Murakami, Y.; Okubo, Y.; Matsubayashi, O.; Tanaka, A.; Nakajima, Y.; Morijiri, R. [Geological Survey of Japan, Tsukuba (Japan); Rokugawa, S. [The University of Tokyo, Tokyo (Japan)

    1997-05-27

    The purpose of this study is to combine seismic activity and volcanic activity by reproducing the formation process of the crustal structure from a physical viewpoint or developing as its extension a numerical simulator which can predict the future. The phenomenon to which attention is especially paid at present is a relation between the dynamic process and the thermal process in the domain including the crust or the upper mantle. Namely, to elucidate the formation process of the crust structure, diastrophism also including seismic activity, igneous activity, etc., it is important to evaluate effects of the behavior of heat supplied from the deep on the dynamic process. In the finite element method, it is not easy to make the effect of gravity reflect to the calculation for boundary conditions. Accordingly, it is general to pay attention to stress difference, considering that stress by gravity is in proportion to static rock pressure stress. Further, to realize interaction between the thermal process and the dynamic process, effects of thermal stress are expressed combining the heat conducting analysis and the plastic flow analysis. 3 refs., 7 figs.

  18. Accurate transport simulation of electron tracks in the energy range 1 keV-4 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Cobut, V. E-mail: vincent.cobut@chim.u-cergy.fr; Cirioni, L.; Patau, J.P

    2004-01-01

    Multipurpose electron transport simulation codes are widely used in the fields of radiation protection and dosimetry. Broadly based on multiple scattering theories and continuous energy loss stopping powers with some mechanism taking straggling into account, they give reliable answers to many problems. However they may be unsuitable in some specific situations. In fact, many of them are not able to accurately describe particle transport through very thin slabs and/or in high atomic number materials, or also when knowledge of high-resolution depth dose distributions is required. To circumvent these deficiencies, we developed a Monte Carlo code simulating each interaction along electron tracks. Gas phase elastic cross sections are corrected to take into account solid state effects. Inelastic interactions are described within the framework of the Martinez et al. [J. Appl. Phys. 67 (1990) 2955] theory intended to deal with energy deposition in both condensed insulators and conductors. The model described in this paper is validated for some materials as aluminium and silicon, encountered in spectrometric and dosimetric devices. Comparisons with experimental, theoretical and other simulation results are made for angular distributions and energy spectra of transmitted electrons through slabs of different thicknesses and for depth energy distributions in semi-infinite media. These comparisons are quite satisfactory.

  19. Application of the Two-Step Filter to Process Ranging Measurements for Relative Navigation in an Elliptical Orbit

    Science.gov (United States)

    Garrison, James L.; Axelrad, Penina

    1997-01-01

    This estimator breaks a nonlinear estimation problem into a set of over determined 'first step' states which are linear in the observations and 'second step' states which are ultimately the states of interest. Linear estimation methods are applied to filter the observations and produce the optimal first step state estimate. The 'second step' states are obtained through iterative nonlinear parameter estimation considering the first step states as observations. It has been shown that this process exactly minimizes the least squares cost function for static problems and provides a better solution than the iterated extended Kalman filter (EKF) for dynamic problems. The two step filter is applied in this paper to process range and range rate measurements between the two spacecraft. Details of the application of the two step estimator to this problem will be given, highlighting the use of a test for ill-conditioned covariance estimates that can result from the first order covariance propagation. A comparison will be made between the performance of the two step filter and the IEKF.

  20. Using the design of simulation experiments to failures interactive effects analysis in process: a hypothetical case

    OpenAIRE

    Fabiano Leal; Dagoberto Alves De Almeida; José Arnaldo Barra Montevechi; Fernando Augusto Silva Marins

    2007-01-01

    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...