WorldWideScience

Sample records for asynchronous particle tracking

  1. 3D asynchronous particle tracking in single and dual continuum matrix-fractures. Application to nuclear waste storage

    International Nuclear Information System (INIS)

    This PhD research was conducted as a collaboration between Laboratoire National d'Hydraulique et Environnement (LNHE) from EDF R and D and the Institut de Mecanique des Fluides de Toulouse (IMFT) in the frame of a CIFRE contract. This PhD thesis aims at providing LNHE a reliable numerical model to study the feasibility of a nuclear waste storage in deep geological structures. The main focus of the thesis is put on developing and implementing a Random Walk Particle Method (RWPM) to model contaminant transport in 3D heterogeneous and fractured porous media. In its first part, the report presents the Lagrangian particle tracking method used to model transport in heterogeneous media with a direct high resolution approach. The solute plume is discretized into concentration packets: particles. The model tracks each particle based on a time-explicit displacement algorithm according to an advective component and a diffusive random component. The method is implemented on a hydraulic model discretized on a 3D unstructured tetrahedral finite element mesh. We focus on techniques to overcome problems due to the discontinuous transport parameters and the unstructured mesh. First, we introduce an asynchronous time-stepping approach to deal with the numerical and overshoot errors that occur with conventional RWPM. Then, a filtering method is applied to smooth discontinuous transport parameters (pre-processing). Finally, once the particle displacements are computed, we propose several filtering and sampling methods to obtain concentrations from particle positions (post-processing). Applications of these methods are presented with cases of tracer advection-dispersion in homogeneous and heterogeneous media. For dense fracture networks, direct high resolution methods are very time consuming and need a lot of computational resources. So, as an alternative to the discrete approach, a dual-continuum representation is used, in the second part of the report, to describe the porous matrix

  2. 3D asynchronous particle tracking in single and dual continuum matrix-fractures. Application to nuclear waste storage; Modelisation 3D du transport particulaire asynchrone en simple et double continuum matrice-fractures: application au stockage de dechets nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Lam, M.Ph

    2008-06-15

    This PhD research was conducted as a collaboration between Laboratoire National d'Hydraulique et Environnement (LNHE) from EDF R and D and the Institut de Mecanique des Fluides de Toulouse (IMFT) in the frame of a CIFRE contract. This PhD thesis aims at providing LNHE a reliable numerical model to study the feasibility of a nuclear waste storage in deep geological structures. The main focus of the thesis is put on developing and implementing a Random Walk Particle Method (RWPM) to model contaminant transport in 3D heterogeneous and fractured porous media. In its first part, the report presents the Lagrangian particle tracking method used to model transport in heterogeneous media with a direct high resolution approach. The solute plume is discretized into concentration packets: particles. The model tracks each particle based on a time-explicit displacement algorithm according to an advective component and a diffusive random component. The method is implemented on a hydraulic model discretized on a 3D unstructured tetrahedral finite element mesh. We focus on techniques to overcome problems due to the discontinuous transport parameters and the unstructured mesh. First, we introduce an asynchronous time-stepping approach to deal with the numerical and overshoot errors that occur with conventional RWPM. Then, a filtering method is applied to smooth discontinuous transport parameters (pre-processing). Finally, once the particle displacements are computed, we propose several filtering and sampling methods to obtain concentrations from particle positions (post-processing). Applications of these methods are presented with cases of tracer advection-dispersion in homogeneous and heterogeneous media. For dense fracture networks, direct high resolution methods are very time consuming and need a lot of computational resources. So, as an alternative to the discrete approach, a dual-continuum representation is used, in the second part of the report, to describe the porous

  3. Selective particle capture by asynchronously beating cilia

    Science.gov (United States)

    Ding, Yang; Kanso, Eva

    2015-12-01

    Selective particle filtration is fundamental in many engineering and biological systems. For example, many aquatic microorganisms use filter feeding to capture food particles from the surrounding fluid, using motile cilia. One of the capture strategies is to use the same cilia to generate feeding currents and to intercept particles when the particles are on the downstream side of the cilia. Here, we develop a 3D computational model of ciliary bands interacting with flow suspended particles and calculate particle trajectories for a range of particle sizes. Consistent with experimental observations, we find optimal particle sizes that maximize capture rate. The optimal size depends nonlinearly on cilia spacing and cilia coordination, synchronous vs. asynchronous. These parameters affect the cilia-generated flow field, which in turn affects particle trajectories. The low capture rate of smaller particles is due to the particles' inability to cross the flow streamlines of neighboring cilia. Meanwhile, large particles have difficulty entering the sub-ciliary region once advected downstream, also resulting in low capture rates. The optimal range of particle sizes is enhanced when cilia beat asynchronously. These findings have potentially important implications on the design and use of biomimetic cilia in processes such as particle sorting in microfluidic devices.

  4. GPU-Based Asynchronous Global Optimization with Particle Swarm

    International Nuclear Information System (INIS)

    The recent upsurge in research into general-purpose applications for graphics processing units (GPUs) has made low cost high-performance computing increasingly more accessible. Many global optimization algorithms that have previously benefited from parallel computation are now poised to take advantage of general-purpose GPU computing as well. In this paper, a global parallel asynchronous particle swarm optimization (PSO) approach is employed to solve three relatively complex, realistic parameter estimation problems in which each processor performs significant computation. Although PSO is readily parallelizable, memory bandwidth limitations with GPUs must be addressed, which is accomplished by minimizing communication among individual population members though asynchronous operations. The effect of asynchronous PSO on robustness and efficiency is assessed as a function of problem and population size. Experiments were performed with different population sizes on NVIDIA GPUs and on single-core CPUs. Results for successful trials exhibit marked speedup increases with the population size, indicating that more particles may be used to improve algorithm robustness while maintaining nearly constant time. This work also suggests that asynchronous operations on the GPU may be viable in stochastic population-based algorithms to increase efficiency without sacrificing the quality of the solutions.

  5. Fuzzy Logic Particle Tracking

    Science.gov (United States)

    2005-01-01

    A new all-electronic Particle Image Velocimetry technique that can efficiently map high speed gas flows has been developed in-house at the NASA Lewis Research Center. Particle Image Velocimetry is an optical technique for measuring the instantaneous two component velocity field across a planar region of a seeded flow field. A pulsed laser light sheet is used to illuminate the seed particles entrained in the flow field at two instances in time. One or more charged coupled device (CCD) cameras can be used to record the instantaneous positions of particles. Using the time between light sheet pulses and determining either the individual particle displacements or the average displacement of particles over a small subregion of the recorded image enables the calculation of the fluid velocity. Fuzzy logic minimizes the required operator intervention in identifying particles and computing velocity. Using two cameras that have the same view of the illumination plane yields two single exposure image frames. Two competing techniques that yield unambiguous velocity vector direction information have been widely used for reducing the single-exposure, multiple image frame data: (1) cross-correlation and (2) particle tracking. Correlation techniques yield averaged velocity estimates over subregions of the flow, whereas particle tracking techniques give individual particle velocity estimates. For the correlation technique, the correlation peak corresponding to the average displacement of particles across the subregion must be identified. Noise on the images and particle dropout result in misidentification of the true correlation peak. The subsequent velocity vector maps contain spurious vectors where the displacement peaks have been improperly identified. Typically these spurious vectors are replaced by a weighted average of the neighboring vectors, thereby decreasing the independence of the measurements. In this work, fuzzy logic techniques are used to determine the true

  6. General defocusing particle tracking.

    Science.gov (United States)

    Barnkob, Rune; Kähler, Christian J; Rossi, Massimiliano

    2015-09-01

    A General Defocusing Particle Tracking (GDPT) method is proposed for tracking the three-dimensional motion of particles in Lab-on-a-chip systems based on a set of calibration images and the normalized cross-correlation function. In comparison with other single-camera defocusing particle-tracking techniques, GDPT possesses a series of key advantages: it is applicable to particle images of arbitrary shapes, it is intuitive and easy to use, it can be used without advanced knowledge of optics and velocimetry theory, it is robust against outliers and overlapping particle images, and it requires only equipment which is standard in microfluidic laboratories. We demonstrate the method by tracking the three-dimensional motion of 2 μm spherical particles in a microfluidic channel using three different optical arrangements. The position of the particles was measured with an estimated uncertainty of 0.1 μm in the in-plane direction and 2 μm in the depth direction for a measurement volume of 1510 × 1270 × 160 μm(3). A ready-to-use GUI implementation of the method can be acquired on . PMID:26201498

  7. On particle track detectors

    Science.gov (United States)

    Benton, E. V.; Gruhn, T. A.; Andrus, C. H.

    1973-01-01

    Aqueous sodium hydroxide is widely used to develop charged particle tracks in polycarbonate film, particularly Lexan. The chemical nature of the etching process for this system has been determined. A method employing ultra-violet absorbance was developed for monitoring the concentration of the etch products in solution. Using this method it was possible to study the formation of the etching solution saturated in etch products. It was found that the system super-saturates to a significant extent before precipitation occurs. It was also learned that the system approaches its equilibrium state rather slowly. It is felt that both these phenomena may be due to the presence of surfactant in the solution. In light of these findings, suggestions are given regarding the preparation and maintenance of the saturated etch solution. Two additional research projects, involving automated techniques for particle track analysis and particle identification using AgCl crystals, are briefly summarized.

  8. A Parallel Particle Swarm Optimization Algorithm Accelerated by Asynchronous Evaluations

    Science.gov (United States)

    Venter, Gerhard; Sobieszczanski-Sobieski, Jaroslaw

    2005-01-01

    A parallel Particle Swarm Optimization (PSO) algorithm is presented. Particle swarm optimization is a fairly recent addition to the family of non-gradient based, probabilistic search algorithms that is based on a simplified social model and is closely tied to swarming theory. Although PSO algorithms present several attractive properties to the designer, they are plagued by high computational cost as measured by elapsed time. One approach to reduce the elapsed time is to make use of coarse-grained parallelization to evaluate the design points. Previous parallel PSO algorithms were mostly implemented in a synchronous manner, where all design points within a design iteration are evaluated before the next iteration is started. This approach leads to poor parallel speedup in cases where a heterogeneous parallel environment is used and/or where the analysis time depends on the design point being analyzed. This paper introduces an asynchronous parallel PSO algorithm that greatly improves the parallel e ciency. The asynchronous algorithm is benchmarked on a cluster assembled of Apple Macintosh G5 desktop computers, using the multi-disciplinary optimization of a typical transport aircraft wing as an example.

  9. PARTICLE BEAM TRACKING CIRCUIT

    Science.gov (United States)

    Anderson, O.A.

    1959-05-01

    >A particle-beam tracking and correcting circuit is described. Beam induction electrodes are placed on either side of the beam, and potentials induced by the beam are compared in a voltage comparator or discriminator. This comparison produces an error signal which modifies the fm curve at the voltage applied to the drift tube, thereby returning the orbit to the preferred position. The arrangement serves also to synchronize accelerating frequency and magnetic field growth. (T.R.H.)

  10. FAST: A fully asynchronous and status-tracking pattern for geoprocessing services orchestration

    Science.gov (United States)

    Wu, Huayi; You, Lan; Gui, Zhipeng; Gao, Shuang; Li, Zhenqiang; Yu, Jingmin

    2014-09-01

    Geoprocessing service orchestration (GSO) provides a unified and flexible way to implement cross-application, long-lived, and multi-step geoprocessing service workflows by coordinating geoprocessing services collaboratively. Usually, geoprocessing services and geoprocessing service workflows are data and/or computing intensive. The intensity feature may make the execution process of a workflow time-consuming. Since it initials an execution request without blocking other interactions on the client side, an asynchronous mechanism is especially appropriate for GSO workflows. Many critical problems remain to be solved in existing asynchronous patterns for GSO including difficulties in improving performance, status tracking, and clarifying the workflow structure. These problems are a challenge when orchestrating performance efficiency, making statuses instantly available, and constructing clearly structured GSO workflows. A Fully Asynchronous and Status-Tracking (FAST) pattern that adopts asynchronous interactions throughout the whole communication tier of a workflow is proposed for GSO. The proposed FAST pattern includes a mechanism that actively pushes the latest status to clients instantly and economically. An independent proxy was designed to isolate the status tracking logic from the geoprocessing business logic, which assists the formation of a clear GSO workflow structure. A workflow was implemented in the FAST pattern to simulate the flooding process in the Poyang Lake region. Experimental results show that the proposed FAST pattern can efficiently tackle data/computing intensive geoprocessing tasks. The performance of all collaborative partners was improved due to the asynchronous mechanism throughout communication tier. A status-tracking mechanism helps users retrieve the latest running status of a GSO workflow in an efficient and instant way. The clear structure of the GSO workflow lowers the barriers for geospatial domain experts and model designers to

  11. Fuzzy logic particle tracking velocimetry

    Science.gov (United States)

    Wernet, Mark P.

    1993-01-01

    Fuzzy logic has proven to be a simple and robust method for process control. Instead of requiring a complex model of the system, a user defined rule base is used to control the process. In this paper the principles of fuzzy logic control are applied to Particle Tracking Velocimetry (PTV). Two frames of digitally recorded, single exposure particle imagery are used as input. The fuzzy processor uses the local particle displacement information to determine the correct particle tracks. Fuzzy PTV is an improvement over traditional PTV techniques which typically require a sequence (greater than 2) of image frames for accurately tracking particles. The fuzzy processor executes in software on a PC without the use of specialized array or fuzzy logic processors. A pair of sample input images with roughly 300 particle images each, results in more than 200 velocity vectors in under 8 seconds of processing time.

  12. Particle tracking with scintillating fibres

    CERN Document Server

    D'Ambrosio, C; Leutz, H; Puertolas, D

    1996-01-01

    This article presents our R&D-work on particle tracking with scintillating fibres. We have developed new fibre dyes, more efficient fibre cladding, coherent fibre bundles with improved packing fraction and a new fibre readout technique (ISPA-tube). Altogether, these new developments increased the hit density of fine grain (60 µm) fibres by about 7 times. This results in mini-tracks per 2.5 mm fibre layer rather than in single hits only and enhances the track reconstruction efficiency to nearly 100 %. Compared with competing tracking methods (silicon strips, MSGCs), our scintillating fibres are superior in hit numbers per radiation length and in the 2-track resolution. They require much less readout channels and consequently no cooling provisions to remove their electronic heat.

  13. Two-Particle Asynchronous Quantum Correlation: Wavefunction Collapse Acting as a Beamsplitter

    Science.gov (United States)

    Kowalski, F. V.; Browne, R. S.

    2016-03-01

    A two-body quantum correlation is calculated for a particle reflecting from a moving mirror. Correlated interference results when the incident and reflected particle substates and their associated mirror substates overlap. Using the Copenhagen interpretation of measurement, an asynchronous joint probability density (PDF), which is a function both of the different positions and different times at which the particle and mirror are measured, is derived assuming that no interaction occurs between each measurement. Measurement of the particle first, in the correlated interference region, results in a splitting of the mirror substate into ones which have and have not reflected the particle. An analog of the interference from the Doppler effect for only measurements of the particle (a marginal PDF), in this two-body system, is shown to be a consequence of the asynchronous measurement. The simplification obtained for a microscopic particle reflecting from a mesoscopic or macroscopic mirror is used to illustrate asynchronous correlation interferometry. In this case, the small displacement between these mirror states can yield negligible environmental decoherence times. In addition, interference of these mirror states does not vanish in the limit of large mirror mass due to the small momentum exchange in reflecting a microscopic particle.

  14. Particle tracking around surface nanobubbles

    CERN Document Server

    Dietrich, Erik; Lohse, Detlef; Seddon, James R T

    2016-01-01

    The exceptionally long lifetime of surface nanobubbles remains one of the biggest questions in the field. One of the proposed mechanisms for the stability is the \\emph{dynamic equilibrium} model, which describes a constant flux of gas in and out of the bubble. Here, we describe results from particle tracking experiments to measure this flow. The results are analysed by measuring the Vorono\\"i cell size distribution, the diffusion, and speed of the tracer particles. We show that there is no detectable difference in the movement of particles above nanobubble-laden surfaces, as compared to nanobubble-free surfaces.

  15. Particle Tracking of Fluorescent Microspheres

    Science.gov (United States)

    Kaminski, Zofia; Mueller, Joachim; Berk, Serkan

    2010-10-01

    In this research, the diffusion coefficients of the fluorescent microspheres and the relation of those coefficients to particle radius were investigated. An additional focus was to see how well the measured radius of the microspheres compared to the radius as reported by the manufacturer and to measure the distribution of radii in a sample. This study further developed the critical process of ensuring particle movement within the sample volume and made preliminary sample measurements.The methods developed for tracking microspheres will later be used to determine the radii of virus like particles (VLPs), which are a non-infectious model system of the HIV virus. Results from our measurements will be reported.

  16. Fast TPC Online Tracking on GPUs and Asynchronous Data Processing in the ALICE HLT to facilitate Online Calibration

    Science.gov (United States)

    Rohr, David; Gorbunov, Sergey; Krzewicki, Mikolaj; Breitner, Timo; Kretz, Matthias; Lindenstruth, Volker

    2015-12-01

    ALICE (A Large Heavy Ion Experiment) is one of the four major experiments at the Large Hadron Collider (LHC) at CERN, which is today the most powerful particle accelerator worldwide. The High Level Trigger (HLT) is an online compute farm of about 200 nodes, which reconstructs events measured by the ALICE detector in real-time. The HLT uses a custom online data-transport framework to distribute data and workload among the compute nodes. ALICE employs several calibration-sensitive subdetectors, e.g. the TPC (Time Projection Chamber). For a precise reconstruction, the HLT has to perform the calibration online. Online- calibration can make certain Offline calibration steps obsolete and can thus speed up Offline analysis. Looking forward to ALICE Run III starting in 2020, online calibration becomes a necessity. The main detector used for track reconstruction is the TPC. Reconstructing the trajectories in the TPC is the most compute-intense step during event reconstruction. Therefore, a fast tracking implementation is of great importance. Reconstructed TPC tracks build the basis for the calibration making a fast online-tracking mandatory. We present several components developed for the ALICE High Level Trigger to perform fast event reconstruction and to provide features required for online calibration. As first topic, we present our TPC tracker, which employs GPUs to speed up the processing, and which bases on a Cellular Automaton and on the Kalman filter. Our TPC tracking algorithm has been successfully used in 2011 and 2012 in the lead-lead and the proton-lead runs. We have improved it to leverage features of newer GPUs and we have ported it to support OpenCL, CUDA, and CPUs with a single common source code. This makes us vendor independent. As second topic, we present framework extensions required for online calibration. The extensions, however, are generic and can be used for other purposes as well. We have extended the framework to support asynchronous compute

  17. Tracking errors in 2D multiple particle tracking microrheology

    International Nuclear Information System (INIS)

    Tracking errors due to particles moving in and out of the focal plane are a fundamental problem of multiple particle tracking microrheology. Here, we present a new approach to treat these errors so that a statistically significant number of particle trajectories with reasonable length are received, which is important for an unbiased analysis of multiple particle tracking data from inhomogeneous fluids. Starting from Crocker and Grier’s tracking algorithm, we identify particle displacements between subsequent images as artificial jumps; if this displacement deviates more than four standard deviations from the mean value, trajectories are terminated at such positions. In a further processing step, trajectories separated by a time gap Δτmax are merged based on an adaptive search radius criterion accounting for individual particle mobility. For a series of Newtonian fluids covering the viscosity range 6–1300 mPa s, this approach yields the correct viscosity but also results in a viscosity-independent number of trajectories equal to the average number of particles in an image with a minimum length covering at least two orders of magnitude in time. This allows for an unbiased characterization of heterogeneous fluids. For a Carbopol ETD 2050 solution we recover the expected broad variation of particle mobility. Consistent with the widely accepted structural model of highly swollen microgel particles suspended in a polymer solution, we find about 2/3 of the tracers are elastically trapped. (paper)

  18. Bayesian target tracking based on particle filter

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    For being able to deal with the nonlinear or non-Gaussian problems, particle filters have been studied by many researchers. Based on particle filter, the extended Kalman filter (EKF) proposal function is applied to Bayesian target tracking. Markov chain Monte Carlo (MCMC) method, the resampling step, etc novel techniques are also introduced into Bayesian target tracking. And the simulation results confirm the improved particle filter with these techniques outperforms the basic one.

  19. A Particle Filter of Blind Equalization and Multiuser Detection in Asynchronous DS/CDMA Systems

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing; DONG Jian-ping; ZHANG Qian

    2008-01-01

    The particle filter (PF) is proposed to be the asynchronous direct-sequence eude-division multiple-access (DS/CDMA) multiuser detector without knowing the channel state information. The PF performs symbol detection according to the joint posterior density probability of simulated particles including relative delays, fading gains and symbols via sequential importance sample and resample. A simplified scheme is also proposed by separating the independent relative delays and fading with symbols. These parameters are modeled as the extended aggressive processes and estimated by the Kalman fdter, so as to provide their arbitrary importance distribution for symbol detection. Simulation results show that the bit error rate of the PF is less than convntional detectors.Moreover, the complexity of PF is moderate comaparable to other nonlinear suboptimal approaches.

  20. Better track leads to new particles

    CERN Multimedia

    2006-01-01

    "Dutch researcher Thijs Cornelissen developed an algorithm to reconstruct the particle tracks and that is being used in a European research institute for particle physics. His method provides greater insights into the origine of particles that arise as a result of collisions." (1/2 page)

  1. A parallel algorithm for 3D particle tracking and Lagrangian trajectory reconstruction

    International Nuclear Information System (INIS)

    Particle-tracking methods are widely used in fluid mechanics and multi-target tracking research because of their unique ability to reconstruct long trajectories with high spatial and temporal resolution. Researchers have recently demonstrated 3D tracking of several objects in real time, but as the number of objects is increased, real-time tracking becomes impossible due to data transfer and processing bottlenecks. This problem may be solved by using parallel processing. In this paper, a parallel-processing framework has been developed based on frame decomposition and is programmed using the asynchronous object-oriented Charm++ paradigm. This framework can be a key step in achieving a scalable Lagrangian measurement system for particle-tracking velocimetry and may lead to real-time measurement capabilities. The parallel tracking algorithm was evaluated with three data sets including the particle image velocimetry standard 3D images data set #352, a uniform data set for optimal parallel performance and a computational-fluid-dynamics-generated non-uniform data set to test trajectory reconstruction accuracy, consistency with the sequential version and scalability to more than 500 processors. The algorithm showed strong scaling up to 512 processors and no inherent limits of scalability were seen. Ultimately, up to a 200-fold speedup is observed compared to the serial algorithm when 256 processors were used. The parallel algorithm is adaptable and could be easily modified to use any sequential tracking algorithm, which inputs frames of 3D particle location data and outputs particle trajectories

  2. Particle Filters for Positioning, Navigation and Tracking

    OpenAIRE

    Gustafsson, Fredrik; Gunnarsson, Fredrik; Bergman, Niclas; Forssell, Urban; Jansson, Jonas; Karlsson, Rickard; Nordlund, Per-Johan

    2001-01-01

    A framework for positioning, navigation and tracking problems using particle filters (sequential Monte Carlo methods) is developed. It consists of a class of motion models and a general non-linear measurement equation in position. A general algorithm is presented, which is parsimonious with the particle dimension. It is based on marginalization, enabling a Kalman filter to estimate all position derivatives, and the particle filter becomes low-dimensional. This is of utmost importance for high...

  3. Discovery Mondays - 'Particle tracks: Seeing the invisible'

    CERN Document Server

    2007-01-01

    Simulation of particle tracks in the CMS detector. How can you 'see' something as infinitesimal and fleeting as an elementary particle that defeats even the most powerful microscope? Well, physicists have detectors to snoop on them. Unlike biologists looking at bacteria, physicists don't see the particles themselves. They study their impact on sensitive materials as they pass through them at ultra high speed, a bit like seeing plane vapour trails in a clear sky. At the next Discovery Monday you will be able to find out about the different methods used at CERN to detect particles. There will be demonstrations of the cloud chamber, where particles leave tell-tale evidence of their passage in tracks of droplets. You will also learn about past and current particle track detection techniques and how the tracks are reconstructed into magnificent composite images. Don't miss this opportunity to learn about the various ways of 'seeing' particles. The event will be conducted in French. Come along to the Microcosm ...

  4. Digital characterization of particle tracks for microdosimetry

    International Nuclear Information System (INIS)

    Work is in progress to develop a digital approach to microdosimetry and to construct a prototype instrument to obtain digital information about charged-particle tracks. The objective of such a device is to measure the numbers of electrons produced in various subvolumes of a chamber gas along a particle's path. This paper describes results of Monte Carlo calculations of charged-particle tracks in a cubical time-projection ionization chamber containing methane. Results are presented to show the effects of electron diffusion during charge collection. The calculations indicate that the optimum ratio of field strength and pressure is about 0.6 volts cm-1 torr-1. Examples of proton, carbon-ion, and electron tracks are shown. 2 refs., 6 figs

  5. Track-nanodosimetry of an alpha particle

    Energy Technology Data Exchange (ETDEWEB)

    De Nardo, L.; Tornielli, G. [Padova Univ., Padova (Italy); INFN, Padova (Italy); Cesari, V.; Colautti, P.; Conte, V. [INFN Laboratori Nazionali, Legnaro (Italy); Baek, W.Y.; Grosswendt, B. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Alkaa, A.; Segur, P. [Centre de Physique des Plasmas et de leur Applications, Toulouse (France)

    2002-07-01

    Effects of radiation are primarily determined by what happens in individual small volumes representative of DNA segments. Such sites are so small that the interactions due to radiation are very few and it is necessary to consider the stochastic of the number and nature of primary interactions and of secondary processes in order to understand the subsequent biological effects. Track-nanodosimetry has the objective to investigate stochastic aspect of energy deposition in particle tracks, by measuring the ionisation distributions induced by a charged particle in nanometric volumes of tissue-equivalent matter, positioned at different distances from the track. This paper is concerned with measurements and Monte Carlo calculations of ionisation distributions produced in a site of about 20 nm by a {sup 244}Cm alpha particle.

  6. Track-nanodosimetry of an alpha particle

    International Nuclear Information System (INIS)

    Effects of radiation are primarily determined by what happens in individual small volumes representative of DNA segments. Such sites are so small that the interactions due to radiation are very few and it is necessary to consider the stochastic of the number and nature of primary interactions and of secondary processes in order to understand the subsequent biological effects. Track-nanodosimetry has the objective to investigate stochastic aspect of energy deposition in particle tracks, by measuring the ionisation distributions induced by a charged particle in nanometric volumes of tissue-equivalent matter, positioned at different distances from the track. This paper is concerned with measurements and Monte Carlo calculations of ionisation distributions produced in a site of about 20 nm by a 244Cm alpha particle

  7. Fast particle tracking with wake fields

    Energy Technology Data Exchange (ETDEWEB)

    Dohlus, M.; Floettmann, K.; Henning, C.

    2012-01-15

    Tracking calculations of charged particles in electromagnetic fields require in principle the simultaneous solution of the equation of motion and of Maxwell's equations. In many tracking codes a simpler and more efficient approach is used: external fields like that of the accelerating structures are provided as field maps, generated in separate computations and for the calculation of self fields the model of a particle bunch in uniform motion is used. We describe how an externally computed wake function can be approximated by a table of Taylor coefficients and how the wake field kick can be calculated for the particle distribution in a tracking calculation. The integrated kick, representing the effect of a distributed structure, is applied at a discrete time. As an example, we use our approach to calculate the emittance growth of a bunch in an undulator beam pipe due to resistive wall wake field effects. (orig.)

  8. Canonical particle tracking in undulator fields

    International Nuclear Information System (INIS)

    A new algebraic mapping routine for particle tracking across wiggler and undulator fields in presented. It is based on a power series expansion of the generating function to guarantee fully canonical transformations. This method is 10 to 100 times faster than integration routines, applied in tracking codes like BETA or RACETRACK. The tracking method presented is not restricted to wigglers and undulators, it can be applied to other magnetic fields as well such as fringing fields of quadrupoles or dipoles if the suggested expansion converges

  9. Dominant Correlogram Based Particle Filter Tracking

    Institute of Scientific and Technical Information of China (English)

    MAO Yan-fen; SHI Peng-fei

    2005-01-01

    A novel dominant correlogram based particle filter was proposed for an object tracking in visual surveillance. Particle filter outperforms the Kalman filter in non-linear and non-Gaussian estimation problem. This paper proposed incorporating spatial information into visual feature, and yields a reliable likelihood description of the observation and prediction. A similarity-ratio is defined to evaluate the effectivity of different similarity measurements in weighing samples. The experimental results demonstrate the effective and robust performance compared with the histogram based tracking in traffic scenes.

  10. Particle Filter for Estimation and Tracking

    Institute of Scientific and Technical Information of China (English)

    Ji-zhen WANG; Zeng-shun ZHAO; Xiao-wei AN; Shu-xia TIAN

    2010-01-01

    In recent years, the particle filter technique has been widely used in tracking, estimation and navigation. In this paper, the authors described several practical filters including the general practical, the extended Kaman practical, and the unscented particle filters. And they explained the degeneracy problem in the practical filter process, and introduced some solved methods. Finally they demonstrated the estimation of different particle filters in non-liner and non-Gaussian situation respectively. The result proved the unscented particle filter had the best performance.

  11. Tracking particles by passing messages between images

    Energy Technology Data Exchange (ETDEWEB)

    Chertkov, Michael [Los Alamos National Laboratory; Kroc, Lukas [Los Alamos National Laboratory; Zdeborova, Lenka [Los Alamos National Laboratory; Krakala, Florent [ESPCI; Vergassola, M [CNRS

    2009-01-01

    Methods to extract information from the tracking of mobile objects/particles have broad interest in biological and physical sciences. Techniques based on the simple criterion of proximity in time-consecutive snapshots are useful to identify the trajectories of the particles. However, they become problematic as the motility and/or the density of the particles increases because of the uncertainties on the trajectories that particles have followed during the acquisition time of the images. Here, we report efficient methods for learning parameters of the dynamics of the particles from their positions in time-consecutive images. Our algorithm belongs to the class of message-passing algorithms, also known in computer science, information theory and statistical physics under the name of Belief Propagation (BP). The algorithm is distributed, thus allowing parallel implementation suitable for computations on multiple machines without significant inter-machine overhead. We test our method on the model example of particle tracking in turbulent flows, which is particularly challenging due to the strong transport that those flows produce. Our numerical experiments show that the BP algorithm compares in quality with exact Markov Chain Monte-Carlo algorithms, yet BP is far superior in speed. We also suggest and analyze a random-distance model that provides theoretical justification for BP accuracy. Methods developed here systematically formulate the problem of particle tracking and provide fast and reliable tools for its extensive range of applications.

  12. Passive target tracking using marginalized particle filter

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A marginalized particle filtering(MPF)approach is proposed for target tracking under the background of passive measurement.Essentially,the MPF is a combination of particle filtering technique and Kalman filter.By making full use of marginalization,the distributions of the tractable linear part of the total state variables are updated analytically using Kalman filter,and only the lower-dimensional nonlinear state variable needs to be dealt with using particle filter.Simulation studies are performed on an illustrative example,and the results show that the MPF method leads to a significant reduction of the tracking errors when compared with the direct particle implementation.Real data test results also validate the effectiveness of the presented method.

  13. Particle tracks fitted on the Riemann sphere

    CERN Document Server

    Strandlie, A; Frühwirth, R; Lillekjendlie, B

    2000-01-01

    We present a novel method of fitting trajectories of charged particles in high-energy physics particle detectors. The method fits a circular arc to two-dimensional measurements by mapping the measurements onto the Riemann sphere and fitting a plane to the transformed coordinates of the measurements. In this way, the non- linear task of circle fitting, which in general requires the application of some iterative procedure, is turned into a linear problem which can be solved in a fast, direct and non-iterative manner. We illustrate the usefulness of our approach by stating results from two simulation experiments of tracks from the ATLAS Inner Detector Transition Radiation Tracker (TRT). The first experiment shows that with a significantly lower execution time, the accuracy of the estimated track parameters is virtually as good as the accuracy obtained by applying an optimal, non-linear least- squares procedure. The second experiment focuses on track parameter estimation in the presence of ambiguous measurements....

  14. Track nanodosimetry of an alpha particle

    International Nuclear Information System (INIS)

    Experimental measurements and calculations are described of ionisation distributions in propane wall-less gas cavities of about 20 nm simulated size, performed at different distances from a 244Cm alpha particle track. Ionisation events are detected one by one by collecting electrons from the sensitive volume and by separating them with a drift column. Experimental results and Monte Carlo calculations indicate that, in the delta ray cloud, conditional probability curves, average cluster size and the ratio of second moment above first moment of the cluster distribution are invariant with track distance. (author)

  15. Track nanodosimetry of an alpha particle.

    Science.gov (United States)

    De Nardo, L; Colautti, P; Baek, W Y; Grosswendt, B; Alkaa, A; Ségur, P; Tornielli, G

    2002-01-01

    Experimental measurements and calculations are described of ionisation distributions in propane wall-less gas cavities of about 20 nm simulated size, performed at different distances from a 244Cm alpha particle track. Ionisation events are detected one by one by collecting electrons from the sensitive volume and by separating them with a drift column. Experimental results and Monte Carlo calculations indicate that, in the delta ray cloud, conditional probability curves, average cluster size and the ratio of second moment above first moment of the cluster distribution are invariant with track distance. PMID:12194323

  16. Track nanodosimetry of an alpha particle

    Energy Technology Data Exchange (ETDEWEB)

    De Nardo, L.; Colautti, P.; Baek, W.Y.; Grosswendt, B.; Alkaa, A.; Segur, P.; Tornielli, G

    2002-07-01

    Experimental measurements and calculations are described of ionisation distributions in propane wall-less gas cavities of about 20 nm simulated size, performed at different distances from a {sup 244}Cm alpha particle track. Ionisation events are detected one by one by collecting electrons from the sensitive volume and by separating them with a drift column. Experimental results and Monte Carlo calculations indicate that, in the delta ray cloud, conditional probability curves, average cluster size and the ratio of second moment above first moment of the cluster distribution are invariant with track distance. (author)

  17. Tracking of human head with particle filter

    Institute of Scientific and Technical Information of China (English)

    GUO Chao

    2009-01-01

    To cope with the problem of tracking a human head in a complicated scene, we propose a method that adopts human skin color and hair color integrated with a kind of particle filter named condensation algorithm. Firstly, a novel method is presented to set up human head color model using skin color and hair color separately based on region growing. Compared with traditional human face model, this method is more precise and works well when human turns around and the face disappears in the image. Then a novel method is presented to use color model in condensation algorithm more effectively. In this method, a combination of edge detection result, color segmentation result and color edge detection result in an Omega window is used to measure the scale and position of human head in condensation. Experiments show that this approach can track human head in complicated scene even when human turns around or the distance of tracking a human head changes quickly.

  18. Detection of single atoms in particle tracks

    International Nuclear Information System (INIS)

    The one-atom detection technique was used to search for atoms which are created from the neutralization of heavy ions as they lose their energy in a gas. When 252Cf decays by binary fission, Cs/super n+/ ions are formed approximately 14% of the time (in the heavy mass peak). Thus, these ions were injected into a gas at a low rate such that the Cs neutral atom could be searched for individually and at a known time after its production. A delay of a few microseconds allowed time for collection of the 3 x 106 electrons created by the 80-MeV Cs/sup n+/ energy; then a pulsed laser was fired along each particle track to remove one electron from each Cs atom by the saturated two-step resonance ionization process. These electrons were then drifted into a gas proportional counter and detected individually to measure the probability that a neutral Cs atom would be found at the end of the fission particle track. The results show that a Cs neutral species is formed about 14% of the time, and thus nearly all Cs/sup n+/ ions become Cs0 when the ions are thermalized in P-10 (90% Ar plus 10% CH4) counting gas. Extensions of the technique to obtain other details of particle track structure are discussed. For example, it is possible to detect even one negative ion created in a track where nearly 100 MeV of energy is absorbed; it is likewise possible to determine the population of quantum-selected excited states left in the wake of these tracks. 4 figures

  19. Collective aspects of charged particle track structure

    International Nuclear Information System (INIS)

    A plasmon generated by a swift charged particle constitutes a coherent excitation about the particle track. We discuss the representation of collective modes in impact parameter space when created by a swift ion or a fast electron, and the decay of these modes into localized excitations. Several alternative spatial representations are considered. We show that the high spatial resolution found in secondary electron emission measurements with scanning electron microscopy is consistent with the existence of the plasmon as an intermediary between the fast incident electron and the measured secondary electrons. 24 refs., 6 figs

  20. Nuclear track radiography of 'hot' aerosol particles

    CERN Document Server

    Boulyga, S F; Kievets, M K; Lomonosova, E M; Zhuk, I V; Yaroshevich, O I; Perelygin, V P; Petrova, R I; Brandt, R; Vater, P

    1999-01-01

    Nuclear track radiography was applied to identify aerosol 'hot' particles which contain elements of nuclear fuel and fallout after Chernobyl NPP accident. For the determination of the content of transuranium elements in radioactive aerosols the measurement of the alpha-activity of 'hot' particles by SSNTD was used in this work, as well as radiography of fission fragments formed as a result of the reactions (n,f) and (gamma,f) in the irradiation of aerosol filters by thermal neutrons and high energy gamma quanta. The technique allowed the sizes and alpha-activity of 'hot' particles to be determined without extracting them from the filter, as well as the determination of the uranium content and its enrichment by sup 2 sup 3 sup 5 U, sup 2 sup 3 sup 9 Pu and sup 2 sup 4 sup 1 Pu isotopes. Sensitivity of determination of alpha activity by fission method is 5x10 sup - sup 6 Bq per particle. The software for the system of image analysis was created. It ensured the identification of track clusters on an optical imag...

  1. Particle Filter with Gaussian Weighting for Human Tracking

    OpenAIRE

    T. Basaruddin; M. Rahmat Widyanto; Indah Agustien Siradjuddin

    2012-01-01

    Particle filter for object tracking could achieve high tracking accuracy.  To track the object, this method generates a number of particles which is the representation of the candidate target object.  The location of target object is determined by particles and each weight. The disadvantage of conventional particle filter is the computational time especially on the computation of particle’s weight.  Particle filter with Gaussian weighting is proposed to accomplish the computational problem.  ...

  2. Biological Insights from Single-Particle Tracking in Living Cells

    OpenAIRE

    Sanamrad, Arash

    2014-01-01

    Single-particle tracking is a technique that allows for quantitative analysis of the localization and movement of particles. In this technique, trajectories are constructed by determining and connecting the positions of individual particles from consecutive images. Recent advances have made it possible to track hundreds of particles in an individual cell by labeling the particles of interest with photoactivatable or photoconvertible fluorescent proteins and tracking one or a few at a time. Si...

  3. Particle Filtering Applied to Musical Tempo Tracking

    Directory of Open Access Journals (Sweden)

    Macleod Malcolm D

    2004-01-01

    Full Text Available This paper explores the use of particle filters for beat tracking in musical audio examples. The aim is to estimate the time-varying tempo process and to find the time locations of beats, as defined by human perception. Two alternative algorithms are presented, one which performs Rao-Blackwellisation to produce an almost deterministic formulation while the second is a formulation which models tempo as a Brownian motion process. The algorithms have been tested on a large and varied database of examples and results are comparable with the current state of the art. The deterministic algorithm gives the better performance of the two algorithms.

  4. Improvement of Multi-Particle Tracking Code COMA

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>COMA is a multi-particle tracking code for cyclotrons. It was developed by TRIUMF in 1975[1]. The code simulates particle acceleration by performing successive transformations on the particle co-ordinates

  5. Discovery Mondays - The detectors: tracking particles

    CERN Multimedia

    2005-01-01

    View of a module from the LHCb vertex detector, which will be presented at the next Discovery Monday. How do you observe the invisible? In order to deepen still further our knowledge of the infinitely small, physicists accelerate beams of particles and generate collisions between them at extraordinary energies. The collisions give birth to showers of new particles. What are they? In order to find out, physicists slip into the role of detectives thanks to the detectors. At the next Discovery Monday you will find out about the different methods used at CERN to detect particles. A cloud chamber will allow you to see the tracks of cosmic particles live. You will also be given the chance to see real modules for the ATLAS and for the LHCb experiments. Strange materials will be on hand, such as crystals that are heavier than iron and yet as transparent as glass... Come to the Microcosm and become a top detective yourself! This event will take place in French. Join us at the Microcosm (Reception Building 33, M...

  6. User's manual for the particle tracking model ZOOPT

    OpenAIRE

    Jackson, C.R.

    2004-01-01

    This report describes the development of a steady-state particle tracking code for use in conjunction with the object-oriented groundwater flow model, ZOOMQ3D (Jackson and Spink, 2004). Like the flow model, the particle tracking software, ZOOPT, is written using an object-oriented approach to promote its extensibility and flexibility. ZOOPT enables the definition of steady-state and time-variant path lines in three dimensions. Particles can be tracked in both the forward and re...

  7. Measuring the 3D motion of particles in microchannel acoustophoresis using astigmatism particle tracking velocimetry

    DEFF Research Database (Denmark)

    Augustsson, P.; Barnkob, Rune; Bruus, Henrik; Kähler, C. J.; Laurell, T.; Marín, Á. G.; Rossi, M.

    We introduce full three-dimensional tracking of particles in an acoustophoresis microchannel using Astigmatism Particle Tracking Velocimetry (APTV) [1]. For the first time the interaction between acoustic streaming and the primary acoustic radiation force in microchannel acoustophoresis are exami...

  8. Measuring the 3D motion of particles in microchannel acoustophoresis using astigmatism particle tracking velocimetry

    DEFF Research Database (Denmark)

    Augustsson, P.; Barnkob, Rune; Bruus, Henrik; Kähler, C. J.; Laurell, T.; Marín, Á. G.; Rossi, M.

    We introduce full three-dimensional tracking of particles in an acoustophoresis microchannel using Astigmatism Particle Tracking Velocimetry (APTV) [1]. For the first time the interaction between acoustic streaming and the primary acoustic radiation force in microchannel acoustophoresis are...

  9. Preparation of uranium containing particles and measurement of fission track

    International Nuclear Information System (INIS)

    In this study, we discussed results of the preparation of uranium containing particles and measurement of fission tracks for the uranium particles. Uranium-doped silica bead and uranium oxide particles were prepared by uranium sorption onto silica bead and laser ablation method, respectively. Fission tracks for the uranium metal, uranium-doped silica bead, and uranium oxide particles were detected on Lexan detector. Correlation of uranium particle diameter with fission track radius were also discussed. Results of the correlation were applied for the calculation of critical angle

  10. A novel clustering approach to positron emission particle tracking

    Science.gov (United States)

    Wiggins, Cody; Santos, Roque; Ruggles, Arthur

    2016-03-01

    A novel approach to positron emission particle tracking is presented based on determining regions of space with high density of line of response crossing via clustering. The method is shown to be able to accurately track multiple particles in systems where the number of particles is unknown and in which particles can enter and leave the field of view of the scanning system. This method is explored in various environments and its parametric dependence is studied.

  11. Improving z-tracking accuracy in the two-photon single-particle tracking microscope

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.; Liu, Y.-L.; Perillo, E. P.; Jiang, N.; Dunn, A. K., E-mail: adunn@utexas.edu, E-mail: tim.yeh@austin.utexas.edu; Yeh, H.-C., E-mail: adunn@utexas.edu, E-mail: tim.yeh@austin.utexas.edu [Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas 78712 (United States)

    2015-10-12

    Here, we present a method that can improve the z-tracking accuracy of the recently invented TSUNAMI (Tracking of Single particles Using Nonlinear And Multiplexed Illumination) microscope. This method utilizes a maximum likelihood estimator (MLE) to determine the particle's 3D position that maximizes the likelihood of the observed time-correlated photon count distribution. Our Monte Carlo simulations show that the MLE-based tracking scheme can improve the z-tracking accuracy of TSUNAMI microscope by 1.7 fold. In addition, MLE is also found to reduce the temporal correlation of the z-tracking error. Taking advantage of the smaller and less temporally correlated z-tracking error, we have precisely recovered the hybridization-melting kinetics of a DNA model system from thousands of short single-particle trajectories in silico. Our method can be generally applied to other 3D single-particle tracking techniques.

  12. Improving z-tracking accuracy in the two-photon single-particle tracking microscope

    International Nuclear Information System (INIS)

    Here, we present a method that can improve the z-tracking accuracy of the recently invented TSUNAMI (Tracking of Single particles Using Nonlinear And Multiplexed Illumination) microscope. This method utilizes a maximum likelihood estimator (MLE) to determine the particle's 3D position that maximizes the likelihood of the observed time-correlated photon count distribution. Our Monte Carlo simulations show that the MLE-based tracking scheme can improve the z-tracking accuracy of TSUNAMI microscope by 1.7 fold. In addition, MLE is also found to reduce the temporal correlation of the z-tracking error. Taking advantage of the smaller and less temporally correlated z-tracking error, we have precisely recovered the hybridization-melting kinetics of a DNA model system from thousands of short single-particle trajectories in silico. Our method can be generally applied to other 3D single-particle tracking techniques

  13. Particle filters for tracking in wireless sensor networks

    OpenAIRE

    Achutegui Roncal, Katrin

    2013-01-01

    The goal of this thesis is the development, implementation and assessment of efficient particle filters (PFs) for various target tracking applications on wireless sensor networks (WSNs). We first focus on developing efficient models and particle filters for indoor tracking using received signal strength (RSS) in WSNs. RSS is a very appealing type of measurement for indoor tracking because of its availability on many existing communication networks. In particular, most cur...

  14. Target tracking in glint noise using a MCMC particle filter

    Institute of Scientific and Technical Information of China (English)

    Hu Hongtao; Jing Zhongliang; Li Anping; Hu Shiqiang; Tian Hongwei

    2005-01-01

    In radar target tracking application, the observation noise is usually non-Gaussian, which is also referred as glint noise. The performances of conventional trackers degra de severely in the presence of glint noise. An improved particle filter, Markov chain Monte Carlo particle filter (MCMC-PF), is applied to cope with radar target tracking when the measurements are perturbed by glint noise. Tracking performance of the filter is demonstrated in the present of glint noise by computer simulation.

  15. Algorithms for tracking of charged particles in circular accelerators

    International Nuclear Information System (INIS)

    An important problem in accelerator design is the determination of the largest stable betatron amplitude. This stability limit is also known as the dynamic aperture. The equations describing the particle motion are non-linear, and the Linear Lattice Functions cannot be used to compute the stability limits. The stability limits are therefore usually searched for by particle tracking. One selects a set of particles with different betatron amplitudes and tracks them for many turns around the machine. The particles which survive a sufficient number of turns are termed stable. This paper concentrates on conservative systems. For this case the particle motion can be described by a Hamiltonian, i.e. tracking particles means application of canonical transformations. Canonical transformations are equivalent to symplectic mappings, which implies that there exist invariants. These invariants should not be destroyed in tracking

  16. Particle Tracking in Circular Accelerators Using the Exact Hamiltonian in SixTrack

    CERN Document Server

    Fjellstrom, Mattias; Hansson, Johan

    2013-12-13

    Particle motion in accelerators is in general complex. Tracking codes are developed to simulate beam dynamics in accelerators. SixTrack is a long lived particle tracking code maintained at CERN, the European Organization for Nuclear Research. A particle accelerator consists of a large number of magnets and other electromagnetic devices that guide the particle through the accelerator. Each device defines its own equation of motion, which often cannot be solved exactly. For this purpose, a number of approximations are introduced in order to facilitate the solution and to speed up the computation. In a high-energy accelerator, the particle has small transverse momentum components. This is exploited in the small-angle approximation. In this approximation the equations of motion are expanded to a low order in the transverse momentum components. In low-energy particle accelerators, or in tracking with large momentum deviations, this approximation is invalid. The equations of motion of a particle passing through a f...

  17. Hybrid Particle and Kalman Filtering for Pupil Tracking in Active IR Illumination Gaze Tracking System

    OpenAIRE

    Jian-nan Chi; Li-hua Xie; Peng-yun Zhang; Yi-fang Lu; Guo-sheng Zhang

    2014-01-01

    A novel pupil tracking method is proposed by combining particle filtering and Kalman filtering for the fast and accurate detection of pupil target in an active infrared source gaze tracking system. Firstly, we utilize particle filtering to track pupil in synthesis triple-channel color map (STCCM) for the fast detection and develop a comprehensive pupil motion model to conduct and analyze the randomness of pupil motion. Moreover, we built a pupil observational model based on the similarity mea...

  18. Constraining human motion for efficient tracking with a particle filter

    OpenAIRE

    Rius, Ignasi; Fernández, Carles; Mozerov, Mikhail; Gonzàlez Sabaté, Jordi

    2006-01-01

    Particle filters are one of the most commonly used techniques for full-body human tracking. However, given the high-dimensionality of the involved models, the number of required particles make the problem computationally very expensive. To overcome this, we present an action specific model of human postures which eases the process by guiding the prediction step of the particle filter, so only feasible human postures are considered. Thus, this model-based tracking approach samples from a first...

  19. Particle orbit tracking on a parallel computer: Hypertrack

    International Nuclear Information System (INIS)

    A program has been written which performs particle orbit tracking on the Intel iPSC/860 distributed memory parallel computer. The tracking is performed using a thin element (TEAPOT-style) approach. A brief description of the structure and performance of the code is presented, along with applications of the code is presented, along with applications of the code to the analysis of accelerator lattices for the SSC. The concept of 'ensemble tracking,' i.e. the tracking of ensemble averages of noninteracting particles such as the emittance, is presented. Preliminary results of such studies are presented

  20. Fluctuations in closed-loop fluorescent particle tracking

    Science.gov (United States)

    Berglund, Andrew J.; McHale, Kevin; Mabuchi, Hideo

    2007-06-01

    We present a comprehensive theory of closed-loop particle tracking for calculating the statistics of a diffusing fluorescent particle’s motion relative to the tracking lock point. A detailed comparison is made between the theory and experimental results, with excellent quantitative agreement found in all cases. A generalization of the theory of (open-loop) fluorescence correlation spectroscopy is developed, and the relationship to previous results is discussed. Two applications of the statistical techniques are given: a method for determining a tracked particle’s localization and an algorithm for rapid particle classification based on real-time analysis of the tracking control signal.

  1. Particle orbit tracking on a parallel computer: Hypertrack

    International Nuclear Information System (INIS)

    A program has been written which performs particle orbit tracking on the Intel iPSC/860 distributed memory parallel computer. The tracking is performed using a thin element approach. A brief description of the structure and performance of the code is presented, along with applications of the code to the analysis of accelerator lattices for the SSC. The concept of ''ensemble tracking'', i.e. the tracking of ensemble averages of noninteracting particles, such as the emittance, is presented. Preliminary results of such studies will be presented. 2 refs., 6 figs

  2. Track reconstruction by GPU in 3D particle tracking detectors

    Energy Technology Data Exchange (ETDEWEB)

    Bozza, Cristiano, E-mail: kryss@sa.infn.it [Department of Physics of the University of Salerno and INFN Gruppo Collegato di Salerno, via Giovanni Paolo II 132, Fisciano, SA 84084 (Italy); De Sio, Chiara [Department of Physics of the University of Salerno and INFN Gruppo Collegato di Salerno, via Giovanni Paolo II 132, Fisciano, SA 84084 (Italy); Kose, Umut [CERN, Geneva (Switzerland); Stellacci, Simona Maria [Department of Physics of the University of Salerno and INFN Gruppo Collegato di Salerno, via Giovanni Paolo II 132, Fisciano, SA 84084 (Italy)

    2015-09-11

    3D detectors for high-energy physics have always needed large computing power. Its availability has sometimes determined the statistics and performance of experiments. The increasing specific computing power of GPUs in recent years offers new opportunities for this field of application that should not be missed. The paper shows a novel algorithm that supports, as a by-product of speed, wider angular acceptance with respect to established techniques based on CPUs. While the algorithm has been developed in the environment of nuclear emulsions, it has been conceived from the very beginning as a tool for general tracking in 3D detectors. The overall logic can apply to many operational contexts in which tracking occurs in high combinatorial background. The performances of the algorithm are evaluated from different points of view, describing the details of the computing technique that are common to tracking problems and discussing measurements and data from a test-beam exposure. Computing speed has been evaluated on a broad variety of hardware, investigating an approximated scaling formula.

  3. Track reconstruction by GPU in 3D particle tracking detectors

    International Nuclear Information System (INIS)

    3D detectors for high-energy physics have always needed large computing power. Its availability has sometimes determined the statistics and performance of experiments. The increasing specific computing power of GPUs in recent years offers new opportunities for this field of application that should not be missed. The paper shows a novel algorithm that supports, as a by-product of speed, wider angular acceptance with respect to established techniques based on CPUs. While the algorithm has been developed in the environment of nuclear emulsions, it has been conceived from the very beginning as a tool for general tracking in 3D detectors. The overall logic can apply to many operational contexts in which tracking occurs in high combinatorial background. The performances of the algorithm are evaluated from different points of view, describing the details of the computing technique that are common to tracking problems and discussing measurements and data from a test-beam exposure. Computing speed has been evaluated on a broad variety of hardware, investigating an approximated scaling formula

  4. Nuclear track detector characterization for alpha-particle spectroscopy

    International Nuclear Information System (INIS)

    Solid State Nuclear Track Detectors (SSNTDs), CR-39™ type, are usually adopted in many applications in which it could be necessary to select tracks according to the incident alpha-particle energy; so several authors have argued that track parameters such as the major/minor axis being the most often reported, can be used to determine the alpha-particle’s energy. However, the use of these parameters only do an univocal result, for example the same axis length can be obtained for different combinations of incident angles and energies. We report on a track analysis performed by a semiautomatic system that classifies tracks according to two parameters, diameter length and mean grey level. This kind of analysis can give information about the track depth, that increases monotonically with the incident energy and angle of the alpha particle. Combining the information on the two parameters it is possible to determine univocally the incident alpha-particle energy values. In order to characterize CR-39 detectors according to the physical track parameters, detectors were irradiated, inside a vacuum chamber, by alpha particles at thirteen energy values, obtained by different mylar layers in front of a 241Am source. After the exposure the detectors were chemically etched to enlarge the tracks and then analyzed by means of a semiautomatic system, consisting on an optical microscope equipped with a CCD camera connected to a personal computer for image storage. A suitable routine analyzed the track parameters: diameter and mean grey level, allowing us to differentiate tracks according to the incident alpha-particle energy and then to individuate the discrimination factors for radon alpha tracks, when nuclear track detectors are applied in radon surveys. - Highlights: ► CR-39. ► Geometric and optical parameter. ► α spectrometry. ► Calibration

  5. Confocal scanner for vertical particle tracks in the nuclear photoemulsion

    International Nuclear Information System (INIS)

    A confocal scanner for selective observation of the vertical particle tracks in the nuclear photoemulsion is described. The particle track being searched for is imaging at an angle of 45 deg with respect to the optical axis of the system. The confocal scanner is provided with a new optical element, an 'image orthogonalizator', by means of which the extended image of the inclined vertical particle track is rotated over an angle of 90 deg. The stereoscopic version of the confocal scanner is presented as well. The described systems will be used in the experiments for investigation of the neutrino oscillations in the accelerators experiments

  6. Registration of light particles by a CN-track detector

    International Nuclear Information System (INIS)

    The validity of the track formation model proposed by Fleischer, Price and Walker was tested for a sensitive cellulose nitrate track detector using protons, deuterons and α particles. Quantitative data are given on the threshold energies and etchable track lengths of these particles. The same data were also calculated for 3H, 3He, 6H, and 8He by means of the model of primary radiation density presented in the paper. A simple empirical relation was found for the evolution of the etch ratio along the particle trajectory. (author)

  7. Optical tracking of nanoscale particles in microscale environments

    Science.gov (United States)

    Mathai, P. P.; Liddle, J. A.; Stavis, S. M.

    2016-03-01

    The trajectories of nanoscale particles through microscale environments record useful information about both the particles and the environments. Optical microscopes provide efficient access to this information through measurements of light in the far field from nanoparticles. Such measurements necessarily involve trade-offs in tracking capabilities. This article presents a measurement framework, based on information theory, that facilitates a more systematic understanding of such trade-offs to rationally design tracking systems for diverse applications. This framework includes the degrees of freedom of optical microscopes, which determine the limitations of tracking measurements in theory. In the laboratory, tracking systems are assemblies of sources and sensors, optics and stages, and nanoparticle emitters. The combined characteristics of such systems determine the limitations of tracking measurements in practice. This article reviews this tracking hardware with a focus on the essential functions of nanoparticles as optical emitters and microenvironmental probes. Within these theoretical and practical limitations, experimentalists have implemented a variety of tracking systems with different capabilities. This article reviews a selection of apparatuses and techniques for tracking multiple and single particles by tuning illumination and detection, and by using feedback and confinement to improve the measurements. Prior information is also useful in many tracking systems and measurements, which apply across a broad spectrum of science and technology. In the context of the framework and review of apparatuses and techniques, this article reviews a selection of applications, with particle diffusion serving as a prelude to tracking measurements in biological, fluid, and material systems, fabrication and assembly processes, and engineered devices. In so doing, this review identifies trends and gaps in particle tracking that might influence future research.

  8. Positron emission particle tracking-Application and labelling techniques

    Institute of Scientific and Technical Information of China (English)

    David J.Parker; Xianfeng Fan

    2008-01-01

    The positron emission particle tracking (PEPT) technique has been widely used in science and engineering to obtain detailed information on the motion and flow fields of fluids or granular materials in multiphase systems, for example, fluids in rock cracks, chemical reactors and food processors; dynamic behaviour of granular materials in chemical reactors, granulators, mixers, dryers, rotating kilns and ball mills. The information obtained by the PEPT technique can be used to optimise the design, operational conditions for a wide range of industrial process systems, and to evaluate modelling work. The technique is based on tracking radioactively labelled particles (up to three particles) by detecting the pairs of back-to-back 511 ke V -γ-rays arising from annihilation of emitted positrons. It therefore involves a positron camera, location algorithms for calculating the tracer location and speed, and tracer labelling techniques. This paper will review the particle tracking technique from tracking algorithm, tracer labelling to their application.

  9. PARTICLE FILTER BASED VEHICLE TRACKING APPROACH WITH IMPROVED RESAMPLING STAGE

    Directory of Open Access Journals (Sweden)

    Wei Leong Khong

    2014-02-01

    Full Text Available Optical sensors based vehicle tracking can be widely implemented in traffic surveillance and flow control. The vast development of video surveillance infrastructure in recent years has drawn the current research focus towards vehicle tracking using high-end and low cost optical sensors. However, tracking vehicles via such sensors could be challenging due to the high probability of changing vehicle appearance and illumination, besides the occlusion and overlapping incidents. Particle filter has been proven as an approach which can overcome nonlinear and non-Gaussian situations caused by cluttered background and occlusion incidents. Unfortunately, conventional particle filter approach encounters particle degeneracy especially during and after the occlusion. Particle filter with sampling important resampling (SIR is an important step to overcome the drawback of particle filter, but SIR faced the problem of sample impoverishment when heavy particles are statistically selected many times. In this work, genetic algorithm has been proposed to be implemented in the particle filter resampling stage, where the estimated position can converge faster to hit the real position of target vehicle under various occlusion incidents. The experimental results show that the improved particle filter with genetic algorithm resampling method manages to increase the tracking accuracy and meanwhile reduce the particle sample size in the resampling stage.

  10. Simultaneous Eye Tracking and Blink Detection with Interactive Particle Filters

    Science.gov (United States)

    Wu, Junwen; Trivedi, Mohan M.

    2007-12-01

    We present a system that simultaneously tracks eyes and detects eye blinks. Two interactive particle filters are used for this purpose, one for the closed eyes and the other one for the open eyes. Each particle filter is used to track the eye locations as well as the scales of the eye subjects. The set of particles that gives higher confidence is defined as the primary set and the other one is defined as the secondary set. The eye location is estimated by the primary particle filter, and whether the eye status is open or closed is also decided by the label of the primary particle filter. When a new frame comes, the secondary particle filter is reinitialized according to the estimates from the primary particle filter. We use autoregression models for describing the state transition and a classification-based model for measuring the observation. Tensor subspace analysis is used for feature extraction which is followed by a logistic regression model to give the posterior estimation. The performance is carefully evaluated from two aspects: the blink detection rate and the tracking accuracy. The blink detection rate is evaluated using videos from varying scenarios, and the tracking accuracy is given by comparing with the benchmark data obtained using the Vicon motion capturing system. The setup for obtaining benchmark data for tracking accuracy evaluation is presented and experimental results are shown. Extensive experimental evaluations validate the capability of the algorithm.

  11. Simultaneous Eye Tracking and Blink Detection with Interactive Particle Filters

    Directory of Open Access Journals (Sweden)

    Mohan M. Trivedi

    2008-04-01

    Full Text Available We present a system that simultaneously tracks eyes and detects eye blinks. Two interactive particle filters are used for this purpose, one for the closed eyes and the other one for the open eyes. Each particle filter is used to track the eye locations as well as the scales of the eye subjects. The set of particles that gives higher confidence is defined as the primary set and the other one is defined as the secondary set. The eye location is estimated by the primary particle filter, and whether the eye status is open or closed is also decided by the label of the primary particle filter. When a new frame comes, the secondary particle filter is reinitialized according to the estimates from the primary particle filter. We use autoregression models for describing the state transition and a classification-based model for measuring the observation. Tensor subspace analysis is used for feature extraction which is followed by a logistic regression model to give the posterior estimation. The performance is carefully evaluated from two aspects: the blink detection rate and the tracking accuracy. The blink detection rate is evaluated using videos from varying scenarios, and the tracking accuracy is given by comparing with the benchmark data obtained using the Vicon motion capturing system. The setup for obtaining benchmark data for tracking accuracy evaluation is presented and experimental results are shown. Extensive experimental evaluations validate the capability of the algorithm.

  12. Multiple object detection and tracking with pseudo-particle filter

    Institute of Scientific and Technical Information of China (English)

    Baolong GUO; Wei SUN

    2009-01-01

    To tackle the divergence of the classical particle filter method for multiple object tracking in image sequences, a new particle filter, called pseudoparticle filter (PPF), is proposed. The PPF invokes subset particles of generic particle filters to form a continuous estimate of the posterior density function of the objects.After sampling-importance resampling (SIR), the subset particles converge to the observations. It is proved that,using an appropriate kernel function of the mean shiift algorithm, we can get the subset particles of the observations and the fixed points of clustering results as the state of the objects. A multiple object data association and state estimation technique is proposed to resolve the subset particles correspondence ambiguities that arise when multiple objects are present. Experimental results demonstrate the efficiency and effectiveness of the algorithm for single and multiple object tracking.

  13. Alpha particle track coloration in CR-39: Improved observability

    CERN Document Server

    Oezguemues, A

    1999-01-01

    A comparative study of the observability of alpha particle tracks in CR-39 was performed with an optical microscope before and after coloration. The implantation of ink helped in observing the damage zones. At first glance through the microscope, the coloration makes the tracks stand out right away. This coloration is helpful, from the start, in the morphological study of the tracks (size, area, orientation, shape, perimeter). This operation is advantageous in distinguishing the alpha particle tracks from stains or scratches. Thus, the routine counting of the tracks is more easily performed. Consequently, this procedure allowed us: to decrease significantly the standard deviation of the approximate total of the parameters given from the image analysis system (Olympus CUE2); to envision the possibility of reasonably decreasing the etching time in order to limit the loss of information caused by the destruction of the CR-39 during chemical etching and to use a weaker enlarging lens in order to cover a larger fi...

  14. Near-wall velocity measurements by Particle-Shadow-Tracking

    CERN Document Server

    Lancien, Pierre; Métivier, François; 10.1007/s00348-007-0260-z

    2009-01-01

    We report a new method to measure the velocity of a fluid in the vicinity of a wall. The method, that we call Particle-Shadow Tracking (PST), simply consists in seeding the fluid with a small number of fine tracer particles of density close to that of the fluid. The position of each particle and of its shadow on the wall are then tracked simultaneously, allowing one to accurately determine the distance separating tracers from the wall and therefore to extract the velocity field. We present an application of the method to the determination of the velocity profile inside a laminar density current flowing along an inclined plane.

  15. Discovery Mondays - The detectors: tracking particles

    CERN Multimedia

    2005-01-01

    View of a module from the LHCb vertex detector, which will be presented at the next Discovery Monday. How do you observe the invisible? In order to deepen still further our knowledge of the infinitely small, physicists accelerate beams of particles at close to the speed of light, then generate collisions between them at extraordinary energies, giving birth to showers of new particles. What are these particles? In order to find out, physicists transform themselves into detectives with the help of the detectors. Located around the collision area, these exceptional machines are made up of various layers, each of which detects and measures specific properties of the particles that travel through them. Powerful computers then reconstruct their trajectory and record their charge, mass and energy in order to build up a kind of particle ID card. At the next Discovery Monday you will be able to find out about the different methods used at CERN to detect particles. A cloud chamber will provide live images of the trac...

  16. Ion-counting nanodosemeter with particle tracking capabilities.

    Science.gov (United States)

    Bashkirov, V; Schulte, R; Breskin, A; Chechik, R; Schemelinin, S; Garty, G; Wroe, A; Sadrozinski, H; Grosswendt, B

    2006-01-01

    An ion-counting nanodosemeter (ND) yielding the distribution of radiation-induced ions in a low-pressure gas within a millimetric, wall-less sensitive volume (SV) was equipped with a silicon microstrip telescope that tracks the primary particles, allowing correlation of nanodosimetric data with particle position relative to the SV. The performance of this tracking ND was tested with a broad 250 MeV proton beam at Loma Linda University Medical Center. The high-resolution tracking capability made it possible to map the ion registration efficiency distribution within the SV, for which only calculated data were available before. It was shown that tracking information combined with nanodosimetric data can map the ionisation pattern of track segments within 150 nm-equivalent long SVs with a longitudinal resolution of approximately 5 tissue-equivalent nanometers. Data acquired in this work were compared with results of Monte Carlo track structure simulations. The good agreement between 'tracking nanodosimetry' data acquired with the new system and simulated data supports the application of ion-counting nanodosimetry in experimental track-structure studies. PMID:17283009

  17. Boosting target tracking using particle filter with flow control

    Science.gov (United States)

    Moshtagh, Nima; Chan, Moses W.

    2013-05-01

    Target detection and tracking with passive infrared (IR) sensors can be challenging due to significant degradation and corruption of target signature by atmospheric transmission and clutter effects. This paper summarizes our efforts in phenomenology modeling of boosting targets with IR sensors, and developing algorithms for tracking targets in the presence of background clutter. On the phenomenology modeling side, the clutter images are generated using a high fidelity end-to-end simulation testbed. It models atmospheric transmission, structured clutter and solar reflections to create realistic background images. The dynamics and intensity of a boosting target are modeled and injected onto the background scene. Pixel level images are then generated with respect to the sensor characteristics. On the tracking analysis side, a particle filter for tracking targets in a sequence of clutter images is developed. The particle filter is augmented with a mechanism to control particle flow. Specifically, velocity feedback is used to constrain and control the particles. The performance of the developed "adaptive" particle filter is verified with tracking of a boosting target in the presence of clutter and occlusion.

  18. A modified variable rate particle filter for maneuvering target tracking

    Institute of Scientific and Technical Information of China (English)

    Yun-fei GUO; Kong-shuai FAN; Dong-liang PENG; Ji-an LUO; Han SHENTU

    2015-01-01

    To address the problem of maneuvering target tracking, where the target trajectory has prolonged smooth regions and abrupt maneuvering regions, a modifi ed variable rate particle fi lter (MVRPF) is proposed. First, a Cartesian-coordinate based variable rate model is presented. Compared with conventional variable rate models, the proposed model does not need any prior knowledge of target mass or external forces. Consequently, it is more convenient in practical tracking applications. Second, a maneuvering detection strategy is adopted to adaptively adjust the parameters in MVRPF, which helps allocate more state points at high maneuver regions and fewer at smooth regions. Third, in the presence of small measurement errors, the unscented particle fi lter, which is embedded in MVRPF, can move more particles into regions of high likelihood and hence can improve the tracking performance. Simulation results illustrate the effectiveness of the proposed method.

  19. Object Tracking Using a Particle Filter with SURF Feature

    Institute of Scientific and Technical Information of China (English)

    Shinfeng DLin; Yu-Ting Jiang; Jia-Jen Lin

    2014-01-01

    In this paper, a novel object tracking based on a particle filter and speeded up robust feature (SURF) is proposed, which uses both color and SURF features. The SURF feature makes the tracking result more robust. On the other hand, the particle selection can lead to save time. In addition, we also consider the matched particle applicable to calculating the SURF weight. Owing to the color, spatial, and SURF features being adopted, this method is more robust than the traditional color-based appearance model. Experimental results demonstrate the robustness and accurate tracking results with challenging sequences. Besides, the proposed method outperforms other methods during the intersection of similar color and object’s partial occlusion.

  20. Charges recombination in α particle tracks in argon

    International Nuclear Information System (INIS)

    The creation and evolution of (neutral) excited states and ionized states in α particle tracks in high pressure argon are studied. The main features of recently published experimental results on the recombination luminescence can be explained and a track model is proposed. Details are given on the track radius, on the electrons thermallization, and on collisions between electrons and triplet excited states. The most important result is that at high pressure and high electron and ion densities a collective electron-ion recombination is possible, that is more efficient that the well known dissociative recombination

  1. Weighted-delta-tracking for Monte Carlo particle transport

    International Nuclear Information System (INIS)

    Highlights: • This paper presents an alteration to the Monte Carlo Woodcock tracking technique. • The alteration improves computational efficiency within regions of high absorbers. • The rejection technique is replaced by a statistical weighting mechanism. • The modified Woodcock method is shown to be faster than standard Woodcock tracking. • The modified Woodcock method achieves a lower variance, given a specified accuracy. - Abstract: Monte Carlo particle transport (MCPT) codes are incredibly powerful and versatile tools to simulate particle behavior in a multitude of scenarios, such as core/criticality studies, radiation protection, shielding, medicine and fusion research to name just a small subset applications. However, MCPT codes can be very computationally expensive to run when the model geometry contains large attenuation depths and/or contains many components. This paper proposes a simple modification to the Woodcock tracking method used by some Monte Carlo particle transport codes. The Woodcock method utilizes the rejection method for sampling virtual collisions as a method to remove collision distance sampling at material boundaries. However, it suffers from poor computational efficiency when the sample acceptance rate is low. The proposed method removes rejection sampling from the Woodcock method in favor of a statistical weighting scheme, which improves the computational efficiency of a Monte Carlo particle tracking code. It is shown that the modified Woodcock method is less computationally expensive than standard ray-tracing and rejection-based Woodcock tracking methods and achieves a lower variance, given a specified accuracy

  2. Video Based Moving Object Tracking by Particle Filter

    Directory of Open Access Journals (Sweden)

    Md. Zahidul Islam

    2009-03-01

    Full Text Available Usually, the video based object tracking deal with non-stationary image stream that changes over time. Robust and Real time moving object tracking is a problematic issue in computer vision research area. Most of the existing algorithms are able to track only inpredefined and well controlled environment. Some cases, they don’t consider non-linearity problem. In our paper, we develop such a system which considers color information, distance transform (DT based shape information and also nonlinearity. Particle filtering has been proven very successful for non-gaussian and non-linear estimation problems. We examine the difficulties of video based tracking and step by step we analyze these issues. In our firstapproach, we develop the color based particle filter tracker that relies on the deterministic search of window, whose color content matches a reference histogram model. A simple HSV histogram-based color model is used to develop this observation system. Secondly, wedescribe a new approach for moving object tracking with particle filter by shape information. The shape similarity between a template and estimated regions in the video scene is measured by their normalized cross-correlation of distance transformed images. Our observation system of particle filter is based on shape from distance transformed edge features. Template is created instantly by selecting any object from the video scene by a rectangle. Finally, inthis paper we illustrate how our system is improved by using both these two cues with non linearity.

  3. Periodic Poisson Solver for Particle Tracking

    CERN Document Server

    Dohlus, M

    2015-01-01

    A method is described to solve the Poisson problem for a three dimensional source distribution that is periodic into one direction. Perpendicular to the direction of periodicity a free space (or open) boundary is realized. In beam physics, this approach allows to calculate the space charge field of a continualized charged particle distribution with periodic pattern. The method is based on a particle mesh approach with equidistant grid and fast convolution with a Green's function. The periodic approach uses only one period of the source distribution, but a periodic extension of the Green's function. The approach is numerically efficient and allows the investigation of periodic- and pseudo-periodic structures with period lengths that are small compared to the source dimensions, for instance of laser modulated beams or of the evolution of micro bunch structures. Applications for laser modulated beams are given.

  4. Inference in particle tracking experiments by passing messages between images.

    Science.gov (United States)

    Chertkov, M; Kroc, L; Krzakala, F; Vergassola, M; Zdeborová, L

    2010-04-27

    Methods to extract information from the tracking of mobile objects/particles have broad interest in biological and physical sciences. Techniques based on simple criteria of proximity in time-consecutive snapshots are useful to identify the trajectories of the particles. However, they become problematic as the motility and/or the density of the particles increases due to uncertainties on the trajectories that particles followed during the images' acquisition time. Here, we report an efficient method for learning parameters of the dynamics of the particles from their positions in time-consecutive images. Our algorithm belongs to the class of message-passing algorithms, known in computer science, information theory, and statistical physics as belief propagation (BP). The algorithm is distributed, thus allowing parallel implementation suitable for computations on multiple machines without significant intermachine overhead. We test our method on the model example of particle tracking in turbulent flows, which is particularly challenging due to the strong transport that those flows produce. Our numerical experiments show that the BP algorithm compares in quality with exact Markov Chain Monte Carlo algorithms, yet BP is far superior in speed. We also suggest and analyze a random distance model that provides theoretical justification for BP accuracy. Methods developed here systematically formulate the problem of particle tracking and provide fast and reliable tools for the model's extensive range of applications. PMID:20368454

  5. Asynchronous Anytime Sequential Monte Carlo

    OpenAIRE

    Paige, Brooks; Wood, Frank; Doucet, Arnaud; Teh, Yee Whye

    2014-01-01

    We introduce a new sequential Monte Carlo algorithm we call the particle cascade. The particle cascade is an asynchronous, anytime alternative to traditional particle filtering algorithms. It uses no barrier synchronizations which leads to improved particle throughput and memory efficiency. It is an anytime algorithm in the sense that it can be run forever to emit an unbounded number of particles while keeping within a fixed memory budget. We prove that the particle cascade is an unbiased mar...

  6. Particle Tracking and Deposition from CFD Simulations using a Viscoelastic Particle Model

    NARCIS (Netherlands)

    Losurdo, M.

    2009-01-01

    In the present dissertation the mathematical modelling of particle deposition is studied and the solution algorithms for particle tracking, deposition and deposit growth are developed. Particle deposition is modelled according to mechanical impact and contact mechanics taking into account the depend

  7. SimTrack: A compact c++ library for particle orbit and spin tracking in accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Yun [Brookhaven National Laboratory (BNL), Upton, NY (United States)

    2015-06-24

    SimTrack is a compact c++ library of 6-d symplectic element-by-element particle tracking in accelerators originally designed for head-on beam-beam compensation simulation studies in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. It provides a 6-d symplectic orbit tracking with the 4th order symplectic integration for magnet elements and the 6-d symplectic synchro-beam map for beam-beam interaction. Since its inception in 2009, SimTrack has been intensively used for dynamic aperture calculations with beam-beam interaction for RHIC. Recently, proton spin tracking and electron energy loss due to synchrotron radiation were added. In this article, I will present the code architecture, physics models, and some selected examples of its applications to RHIC and a future electron-ion collider design eRHIC.

  8. A novel particle tracking algorithm using polar coordinate system similarity

    Institute of Scientific and Technical Information of China (English)

    Xiaodong Ruan; Wenfeng Zhao; Yunming Chen

    2005-01-01

    A new algorithm using polar coordinate system similarity (PCSS) for tracking particle in particle tracking velocimetry (PTV) is proposed. The essence of the algorithm is to consider simultaneously the changes of the distance and angle of surrounding particles relative to the object particle.Monte Carlo simulations of a solid body rotational flow and a parallel shearing flow are used to investigate flows measurable by PCSS and the influences of experimental parameters on the implementation of the new algorithm. The results indicate that the PCSS algorithm can be applied to flows subjected to strong rotation and is not sensitive to experimental parameters in comparison with the conventional binary image cross-correlation (BICC) algorithm. Finally, PCSS is applied to images of a real experiment.

  9. A Voronoi Grid and a Particle Tracking Algorithm for DSMC

    OpenAIRE

    Stollmeier, Frank; Grabe, Martin

    2011-01-01

    The DSMC method simulates a gas by three uncoupled steps: moving representative particles through a physical domain, performing probabilistic collisions and estimating the macroscopic state by ensemble averaging. In order to ease computational treatment of these three steps it is convenient to discretize the space with a grid that fits into the boundaries of the physical domain. For efficient particle tracking it is useful that the cells of this grid are convex polyhedra which pr...

  10. Single-particle tracking for DNA tether length monitoring

    OpenAIRE

    Pouget, Noëlle; Dennis, Cynthia; Turlan, Catherine; Grigoriev, Mikhail; Chandler, Michaël; Salomé, Laurence

    2004-01-01

    We describe a simple single-particle tracking approach for monitoring the length of DNA molecules in tethered particle motion experiments. In this method, the trajectory of a submicroscopic bead tethered by a DNA molecule to a glass surface is determined by videomicroscopy coupled to image analysis. The amplitude of motion of the bead is measured by the standard deviation of the distribution of successive positions of the bead in a given time interval. We were able to describe theoretically t...

  11. Tracking Intermittently Speaking Multiple Speakers Using a Particle Filter

    Directory of Open Access Journals (Sweden)

    Quinlan Angela

    2009-01-01

    Full Text Available The problem of tracking multiple intermittently speaking speakers is difficult as some distinct problems must be addressed. The number of active speakers must be estimated, these active speakers must be identified, and the locations of all speakers including inactive speakers must be tracked. In this paper we propose a method for tracking intermittently speaking multiple speakers using a particle filter. In the proposed algorithm the number of active speakers is firstly estimated based on the Exponential Fitting Test (EFT, a source number estimation technique which we have proposed. The locations of the speakers are then tracked using a particle filtering framework within which the decomposed likelihood is used in order to decouple the observed audio signal and associate each element of the decomposed signal with an active speaker. The tracking accuracy is then further improved by the inclusion of a silence region detection step and estimation of the noise-only covariance matrix. The method was evaluated using live recordings of 3 speakers and the results show that the method produces highly accurate tracking results.

  12. Evaluation of a digital optical ionizing radiation particle track detector

    International Nuclear Information System (INIS)

    An ionizing radiation particle track detector is outlined which can, in principle, determine the three-dimensional spatial distribution of all the secondary electrons produced by the passage of ionizing radiation through a low-pressure (0.1 to 10 kPa) gas. The electrons in the particle track are excited by the presence of a high-frequency AC electric field, and two digital cameras image the optical radiation produced in electronic excitation collisions of the surroundings gas by the electrons. The specific requirements of the detector for neutron dosimetry and microdosimetry are outlined (i.e., operating conditions of the digital cameras, high voltage fields, gas mixtures, etc.) along with an estimate of the resolution and sensitivity achievable with this technique. The proposed detector is shown to compare favorable with other methods for obtaining the details of the track structure, particularly in the quality of the information obtainable about the particle track and the comparative simplicity and adaptability of the detector for measuring the secondary electron track structure for many forms of ionizing radiation over a wide range of energies

  13. Physical Models for Particle Tracking Simulations in the RF Gap

    International Nuclear Information System (INIS)

    This document describes the algorithms that are used in the PyORBIT code to track the particles accelerated in the Radio-Frequency cavities. It gives the mathematical description of the algorithms and the assumptions made in each case. The derived formulas have been implemented in the PyORBIT code. The necessary data for each algorithm are described in detail.

  14. 3D Visual Tracking with Particle and Kalman Filters

    OpenAIRE

    Bayramli, Burak

    2010-01-01

    One of the most visually demonstrable and straightforward uses of filtering is in the field of Computer Vision. In this document we will try to outline the issues encountered while designing and implementing a particle and kalman filter based tracking system.

  15. Physical Models for Particle Tracking Simulations in the RF Gap

    Energy Technology Data Exchange (ETDEWEB)

    Shishlo, Andrei P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holmes, Jeffrey A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-06-01

    This document describes the algorithms that are used in the PyORBIT code to track the particles accelerated in the Radio-Frequency cavities. It gives the mathematical description of the algorithms and the assumptions made in each case. The derived formulas have been implemented in the PyORBIT code. The necessary data for each algorithm are described in detail.

  16. Bearings-Only Tracking of Manoeuvring Targets Using Particle Filters

    Directory of Open Access Journals (Sweden)

    M. Sanjeev Arulampalam

    2004-11-01

    Full Text Available We investigate the problem of bearings-only tracking of manoeuvring targets using particle filters (PFs. Three different (PFs are proposed for this problem which is formulated as a multiple model tracking problem in a jump Markov system (JMS framework. The proposed filters are (i multiple model PF (MMPF, (ii auxiliary MMPF (AUX-MMPF, and (iii jump Markov system PF (JMS-PF. The performance of these filters is compared with that of standard interacting multiple model (IMM-based trackers such as IMM-EKF and IMM-UKF for three separate cases: (i single-sensor case, (ii multisensor case, and (iii tracking with hard constraints. A conservative CRLB applicable for this problem is also derived and compared with the RMS error performance of the filters. The results confirm the superiority of the PFs for this difficult nonlinear tracking problem.

  17. Particle Tracking and Deposition from CFD Simulations using a Viscoelastic Particle Model

    OpenAIRE

    Losurdo, M.

    2009-01-01

    In the present dissertation the mathematical modelling of particle deposition is studied and the solution algorithms for particle tracking, deposition and deposit growth are developed. Particle deposition is modelled according to mechanical impact and contact mechanics taking into account the dependency on time, temperature and particle-deposit composition explicitly. Indeed, such a model lies in the field of the rheology of visco-elastic solids which the author of this dissertation refers to...

  18. On the optical contrast of particle tracks in nuclear track detectors

    International Nuclear Information System (INIS)

    A study was made of the optical contrast of alpha-particle tracks normally incident on cellulose nitrate at all the phases of their development. Measurements of the optical contrast of the spots were performed using a microdensitometer. It was found that the maximum contrast corresponds to the point at which the particle reaches the end of its trajectory. Comparisons of the results of the present work with those obtained by other methods are discussed. (Auth.)

  19. Optimizing experimental parameters for tracking of diffusing particles

    Science.gov (United States)

    Vestergaard, Christian L.

    2016-08-01

    We describe how a single-particle tracking experiment should be designed in order for its recorded trajectories to contain the most information about a tracked particle's diffusion coefficient. The precision of estimators for the diffusion coefficient is affected by motion blur, limited photon statistics, and the length of recorded time series. We demonstrate for a particle undergoing free diffusion that precision is negligibly affected by motion blur in typical experiments, while optimizing photon counts and the number of recorded frames is the key to precision. Building on these results, we describe for a wide range of experimental scenarios how to choose experimental parameters in order to optimize the precision. Generally, one should choose quantity over quality: experiments should be designed to maximize the number of frames recorded in a time series, even if this means lower information content in individual frames.

  20. Evaluation of nanoparticle tracking analysis for total virus particle determination

    Directory of Open Access Journals (Sweden)

    Kramberger Petra

    2012-11-01

    Full Text Available Abstract The NanoSight LM10 with Nanoparticle tracking analysis (NTA software was evaluated for the quantification of latex particles, adenovirus 5, and influenza virus. The inter-day variability was determined by measuring the same sample over several consecutive days and the method’s accuracy was demonstrated by using known concentrations of the subject particles. NTA analysis was also used to quantify chromatographic fractions of adenovirus and influenza virus after purification on a CIM monolithic column. NTA results were compared and evaluated against hemagglutination (HA and end point dilution assay, determining total and infection virus particle number, respectively. The results demonstrated that nanoparticle tracking analysis is a method for fast estimation of virus concentration in different samples. In addition, it can provide a better insight into the sample status, regarding the level of virus aggregation.

  1. Collaborative research on fluidization employing computer-aided particle tracking

    International Nuclear Information System (INIS)

    The objective of this work is to obtain unique, fundamental information on fluidization dynamics over a wide range of flow regimes using a Transportable Computer-Aided Particle Tracking Apparatus (TCAPTA). The contractor will design and fabricate a transportable version of the Computer-Aided Particle Tracking Facility (CAPTF) he has previously developed. The contractor will install and operate the (TCAPTA) at the METC fluidization research facilities. Quantitative data on particle motion will be obtained and reduced. The data will be used to provide needed information for modeling of bed dynamics, and prediction of bed performance, including erosion. A radioactive tracer particle, identical in size shape and mass to the bed particles under study, is mixed in the bed. The radiation emitted by the tracer particle, monitored continuously by 16 scintillation detectors, allows its position to be determined as a function of time. Stochastic mixing processes intrinsic to fluidization further cause the particle to travel to all active regions of the bed, thus sampling the motion in these regions. After a long test run to insure that a sufficient sampling have been acquired, time-differentiation and other statistical processing will then yield the mean velocity distribution, the fluctuating velocity distribution, many types of auto- and cross correlations, as well as mean fluxes, including the mean momentum fluxes due to random motion, which represent the kinetic contributions to the mean stress tensor

  2. Alpha particle track coloration in CR-39: Improved observability

    International Nuclear Information System (INIS)

    A comparative study of the observability of alpha particle tracks in CR-39 was performed with an optical microscope before and after coloration. The implantation of ink helped in observing the damage zones. At first glance through the microscope, the coloration makes the tracks stand out right away. This coloration is helpful, from the start, in the morphological study of the tracks (size, area, orientation, shape, perimeter). This operation is advantageous in distinguishing the alpha particle tracks from stains or scratches. Thus, the routine counting of the tracks is more easily performed. Consequently, this procedure allowed us: to decrease significantly the standard deviation of the approximate total of the parameters given from the image analysis system (Olympus CUE2); to envision the possibility of reasonably decreasing the etching time in order to limit the loss of information caused by the destruction of the CR-39 during chemical etching and to use a weaker enlarging lens in order to cover a larger field of observation for the counting operations

  3. Joint Audio-Visual Tracking Using Particle Filters

    Directory of Open Access Journals (Sweden)

    Dmitry N. Zotkin

    2002-11-01

    Full Text Available It is often advantageous to track objects in a scene using multimodal information when such information is available. We use audio as a complementary modality to video data, which, in comparison to vision, can provide faster localization over a wider field of view. We present a particle-filter based tracking framework for performing multimodal sensor fusion for tracking people in a videoconferencing environment using multiple cameras and multiple microphone arrays. One advantage of our proposed tracker is its ability to seamlessly handle temporary absence of some measurements (e.g., camera occlusion or silence. Another advantage is the possibility of self-calibration of the joint system to compensate for imprecision in the knowledge of array or camera parameters by treating them as containing an unknown statistical component that can be determined using the particle filter framework during tracking. We implement the algorithm in the context of a videoconferencing and meeting recording system. The system also performs high-level semantic analysis of the scene by keeping participant tracks, recognizing turn-taking events and recording an annotated transcript of the meeting. Experimental results are presented. Our system operates in real-time and is shown to be robust and reliable.

  4. Channel Tracking Using Particle Filtering in Unresolvable Multipath Environments

    Directory of Open Access Journals (Sweden)

    Tanya Bertozzi

    2004-11-01

    Full Text Available We propose a new timing error detector for timing tracking loops inside the Rake receiver in spread spectrum systems. Based on a particle filter, this timing error detector jointly tracks the delays of each path of the frequency-selective channels. Instead of using a conventional channel estimator, we have introduced a joint time delay and channel estimator with almost no additional computational complexity. The proposed scheme avoids the drawback of the classical early-late gate detector which is not able to separate closely spaced paths. Simulation results show that the proposed detectors outperform the conventional early-late gate detector in indoor scenarios.

  5. Tracking Submicron Particles in Microchannel Flow by Microscopic Holography

    Institute of Scientific and Technical Information of China (English)

    罗锐; 刘石

    2012-01-01

    Three-dimensional tracking of submicron particles in flows in a micro-channel was carried out using in-line holographic microscopy.A fixed single 0.5 μm fluorescent particle was identified and isolated from dust particles or overlapped particle pair using the laser induced fluorescent(LIF) method.Then in-line microscopic holograms of the fixed single particle were obtained at different positions on the optical axis,i.e.the defocus distances.The holograms of the single particle were used as the model templates with the known defocus distances.The particles in the in-line microscopic holograms of flow in the microchannel were then identified and located to obtain their two-dimensional positions.The defocus distances of those particles were determined by matching each hologram pattern to one of the model templates obtained in the single particle test.Finally the three-dimensional position and velocity of each particle were obtained.

  6. Aging in dense suspensions of soft thermosensitive microgel particles studied with particle-tracking microrheology

    NARCIS (Netherlands)

    Ende, van den Dirk; Purnomo, Eko H.; Duits, Michel H.G.; Richtering, Walter; Mugele, Frieder

    2010-01-01

    Using particle tracking microrheology, we studied the glass transition in dense suspensions of thermosensitive microgel particles. These suspensions can be tuned reversibly between the glass state at low temperature and the liquid state at high temperature. In the glass state, the ensemble averaged

  7. Particle filters for object tracking: enhanced algorithm and efficient implementations

    International Nuclear Information System (INIS)

    Object tracking and recognition is a hot research topic. In spite of the extensive research efforts expended, the development of a robust and efficient object tracking algorithm remains unsolved due to the inherent difficulty of the tracking problem. Particle filters (PFs) were recently introduced as a powerful, post-Kalman filter, estimation tool that provides a general framework for estimation of nonlinear/ non-Gaussian dynamic systems. Particle filters were advanced for building robust object trackers capable of operation under severe conditions (small image size, noisy background, occlusions, fast object maneuvers ..etc.). The heavy computational load of the particle filter remains a major obstacle towards its wide use.In this thesis, an Excitation Particle Filter (EPF) is introduced for object tracking. A new likelihood model is proposed. It depends on multiple functions: position likelihood; gray level intensity likelihood and similarity likelihood. Also, we modified the PF as a robust estimator to overcome the well-known sample impoverishment problem of the PF. This modification is based on re-exciting the particles if their weights fall below a memorized weight value. The proposed enhanced PF is implemented in software and evaluated. Its results are compared with a single likelihood function PF tracker, Particle Swarm Optimization (PSO) tracker, a correlation tracker, as well as, an edge tracker. The experimental results demonstrated the superior performance of the proposed tracker in terms of accuracy, robustness, and occlusion compared with other methods Efficient novel hardware architectures of the Sample Important Re sample Filter (SIRF) and the EPF are implemented. Three novel hardware architectures of the SIRF for object tracking are introduced. The first architecture is a two-step sequential PF machine, where particle generation, weight calculation and normalization are carried out in parallel during the first step followed by a sequential re

  8. Particle track structure and its correlation with radiobiological endpoint

    International Nuclear Information System (INIS)

    One of the possible ways to classify track structures is application of conventional partition techniques of analysis of multidimensional data to the track structure. Using these cluster algorithms this paper attempts to find characteristics of radiation reflecting spatial distribution of ionizations in the primary particle track. Absolute frequency distributions of clusters giving the mean number of clusters produced by radiation per unit of deposited energy have been computed for radiations of different qualities. Results were compared with published data of cell inactivation. For particular biological objects the critical properties of radiation correlating with the cell inactivation can be found and it seems that the occurrence of a cluster of at least four ionizations formed in a domain of ∼2-3 nm correlates with the induction of double strand break. (author)

  9. Formation of particle tracks in solids and their technological application

    International Nuclear Information System (INIS)

    The phenomenon of discrete, directed, and developable ion tracks opens the possibility to structure and modify materials with individual atomic particles on a mesoscopic scale at a high level of pre-determination. The depth and sharpness of this microtool foreshadows new stimuli for a variety of fields. The technique is based on the possibility to amplify a quasi one-dimensional damage zone - engraved by the passage of an ion through an insulating solid - chemically by several orders of magnitude - a key feature for the practical application of the technique. The report reviews the exploration of the technique and outlines its relevant properties applicable to materials science and microstructure technology: Basic features of ion tracks - creation of defects - enhancement and annealing - selective chemical etching - available parameters, Ion track applications - single pores - filtration and membranes - stimulus-responsive membranes - creation of anisotropy - heavy-ion lithography - surface texture - focussed ion beams. (author)

  10. The Timepix Telescope for high performance particle tracking

    Energy Technology Data Exchange (ETDEWEB)

    Akiba, K. [Federal University of Rio de Janeiro, Rio de Janeiro (Brazil); Ronning, P. [CERN, The European Organisation for Nuclear Research, Geneva (Switzerland); Beuzekom, M. van; Beveren, V. van [NIKHEF, Amsterdam (Netherlands); Borghi, S. [University of Manchester, Manchester, Lancashire (United Kingdom); Boterenbrood, H. [NIKHEF, Amsterdam (Netherlands); Buytaert, J.; Collins, P. [CERN, The European Organisation for Nuclear Research, Geneva (Switzerland); Dosil Suárez, A. [Universidade de Santiago de Compostela, Santiago de Compostela (Spain); Dumps, R. [CERN, The European Organisation for Nuclear Research, Geneva (Switzerland); Eklund, L. [Glasgow University, Glasgow, Lanarkshire (United Kingdom); Esperante, D.; Gallas, A. [Universidade de Santiago de Compostela, Santiago de Compostela (Spain); Gordon, H. [University of Oxford, Oxfordshire (United Kingdom); Heijden, B. van der [NIKHEF, Amsterdam (Netherlands); Hombach, C. [University of Manchester, Manchester, Lancashire (United Kingdom); Hynds, D. [Glasgow University, Glasgow, Lanarkshire (United Kingdom); John, M. [University of Oxford, Oxfordshire (United Kingdom); Leflat, A. [Lomonosov Moscow State University, Moscow (Russian Federation); Li, Y. [University of Oxford, Oxfordshire (United Kingdom); and others

    2013-09-21

    The Timepix particle tracking telescope has been developed as part of the LHCb VELO Upgrade project, supported by the Medipix Collaboration and the AIDA framework. It is a primary piece of infrastructure for the VELO Upgrade project and is being used for the development of new sensors and front end technologies for several upcoming LHC trackers and vertexing systems. The telescope is designed around the dual capability of the Timepix ASICs to provide information about either the deposited charge or the timing information from tracks traversing the 14×14 mm matrix of 55×55μm pixels. The rate of reconstructed tracks available is optimised by taking advantage of the shutter driver readout architecture of the Timepix chip, operated with existing readout systems. Results of tests conducted in the SPS North Area beam facility at CERN show that the telescope typically provides reconstructed track rates during the beam spills of between 3.5 and 7.5 kHz, depending on beam conditions. The tracks are time stamped with 1 ns resolution with an efficiency of above 98% and provide a pointing resolution at the centre of the telescope of ∼1.6μm. By dropping the time stamping requirement the rate can be increased to ∼15kHz, at the expense of a small increase in background. The telescope infrastructure provides CO{sub 2} cooling and a flexible mechanical interface to the device under test, and has been used for a wide range of measurements during the 2011–2012 data taking campaigns. -- Highlights: • We provide a technical description of the Timepix Telescope for particle tracking applications. • We demonstrate the spatial and timing resolution to be 2μm and 1 ns respectively. • The maximum particle rate is 7.5 kHz with highly resolved timing and spacing. • The maximum particle rate is 15 kHz with only highly resolved spacing. • We briefly describe the software and tracking algorithms used to achieve this.

  11. Natural tracer test simulation by stochastic particle tracking method

    International Nuclear Information System (INIS)

    Stochastic particle tracking methods are well adapted to 3D transport simulations where discretization requirements of other methods usually cannot be satisfied. They do need a very accurate approximation of the velocity field. The described code is based on the mixed hybrid finite element method (MHFEM) to calculated the piezometric and velocity field. The random-walk method is used to simulate mass transport. The main advantages of the MHFEM over FD or FE are the simultaneous calculation of pressure and velocity, which are considered as unknowns; the possibility of interpolating velocities everywhere; and the continuity of the normal component of the velocity vector from one element to another. For these reasons, the MHFEM is well adapted for particle tracking methods. After a general description of the numerical methods, the model is used to simulate the observations made during the Twin Lake Tracer Test in 1983. A good match is found between observed and simulated heads and concentrations. (Author) (12 refs., 4 figs.)

  12. Investigation of granular impact using positron emission particle tracking

    KAUST Repository

    Marston, Jeremy O.

    2015-04-01

    We present results from an experimental study of granular impact using a combination of high-speed video and positron emission particle tracking (PEPT). The PEPT technique exploits the annihilation of photons from positron decay to determine the position of tracer particles either inside a small granular bed or attached to the object which impacts the bed. We use dense spheres as impactors and the granular beds are comprised of glass beads which are fluidised to achieve a range of different initial packing states. For the first time, we have simultaneously investigated both the trajectory of the sphere, the motion of particles in a 3-D granular bed and particles which jump into the resultant jet, which arises from the collapse of the cavity formed by the impacting sphere.

  13. Particle Tracking and Simulation on the .NET Framework

    International Nuclear Information System (INIS)

    Particle tracking and simulation studies are becoming increasingly complex. In addition to the use of more sophisticated graphics, interactive scripting is becoming popular. Compatibility with different control systems requires network and database capabilities. It is not a trivial task to fulfill all the various requirements without sacrificing runtime performance. We evaluated the effectiveness of the .NET framework by converting a C++ simulation code to C. The portability to other platforms is mentioned in terms of Mono

  14. The Timepix Telescope for High Performance Particle Tracking

    CERN Document Server

    Akiba, Kazuyoshi; van Beuzekom, Martin; van Beveren, Vincent; Borghi, Silvia; Boterenbrood, Henk; Buytaert, Jan; Collins, Paula; Dosil Suárez, Alvaro; Dumps, Raphael; Eklund, Lars; Esperante, Daniel; Gallas, Abraham; Gordon, Hamish; van der Heijden, Bas; Hombach, Christoph; Hynds, Daniel; John, Malcolm; Leflat, Alexander; Li, Yi Ming; Longstaff, Ian; Morton, Alexander; Nakatsuka, Noritsugu; Nomerotski, Andre; Parkes, Chris; Perez Trigo, Eliseo; Plackett, Richard; Reid, Matthew M; Rodriguez Perez, Pablo; Schindler, Heinrich; Szumlak, Tomasz; Tsopelas, Panagiotis; Vázquez Sierra, Carlos; Velthuis, Jaap; Wysokinski, Michal

    2013-01-01

    The Timepix particle tracking telescope has been developed as part of the LHCb VELO Upgrade project, supported by the Medipix Collaboration and the AIDA framework. It is a primary piece of infrastructure for the VELO Upgrade project and is being used for the development of new sensors and front end technologies for several upcoming LHC trackers and vertexing systems. The telescope is designed around the dual capability of the Timepix ASICs to provide information about either the deposited charge or the timing information from tracks traversing the 14 x 14mm matrix of 55 x 55 um pixels. The rate of reconstructed tracks available is optimised by taking advantage of the shutter driven readout architecture of the Timepix chip, operated with existing readout systems. Results of tests conducted in the SPS North Area beam facility at CERN show that the telescope typically provides reconstructed track rates during the beam spills of between 3.5 and 7.5 kHz, depending on beam conditions. The tracks are time stamped wi...

  15. From Waves to Particle Tracks and Quantum Probabilities

    Science.gov (United States)

    Falkenburg, Brigitte

    Here, the measurement methods for identifying massive charged particles are investigated. They have been used from early cosmic ray studies up to the present day. Laws such as the classical Lorentz force and Einstein's relativistic kinematics were established before the rise of quantum mechanics. Later, it became crucial to measure the energy loss of charged particles in matter. In 1930, Bethe developed a semi-classical model based on the quantum mechanics of scattering. In the early 1930s, he and others calculated the passage of charged particles through matter including pair creation and bremsstrahlung. Due to missing trust in quantum electrodynamics, however, only semi-empirical methods were employed in order to estimate the mass and charge from the features of particle tracks. In 1932, Anderson inserted a lead plate into the cloud chamber in order to determine the flight direction and charge of the `positive electron'. In the 1940s, nuclear emulsions helped to resolve puzzles about particle identification and quantum electrodynamics. Later, the measurement theory was extended in a cumulative process by adding conservation laws for dynamic properties, probabilistic quantum formulas for resonances, scattering cross sections, etc. The measurement method was taken over from cosmic ray studies to the era of particle accelerators, and finally taken back from there to astroparticle physics. The measurement methods remained the same, but in the transition from particle to astroparticle physics the focus of interest shifted. Indeed, the experimental methods of both fields explore the grounds of `new physics' in complementary ways.

  16. Tracking Water Diffusion Fronts in a Highly Viscous Aerosol Particle

    Science.gov (United States)

    Bastelberger, Sandra; Krieger, Ulrich; Peter, Thomas

    2016-04-01

    Field measurements indicate that atmospheric secondary aerosol particles can be present in a highly viscous, glassy state [1]. In contrast to liquid state particles, the gas phase equilibration is kinetically limited and governed by condensed phase diffusion. In recent water diffusion experiments on highly viscous single aerosol particles levitated in an electrodynamic balance (EDB) we observed a characteristic shift behavior of the Mie whispering gallery modes (WGM) indicative of the changing radial structure of the particle, thus providing us with an experimental method to track the diffusion process inside the particle. When a highly viscous, homogeneous particle is exposed to an abrupt increase in relative humidity, the rapid gas phase diffusion and strong concentration dependence of the diffusion coefficient in the condensed phase lead to extremely steep water concentration gradients inside the particle, reminiscent of diffusion fronts. The resulting quasi step-like concentration profile motivates the introduction of a simple core-shell model describing the morphology of the non-equilibrium particle during humidification. The subsequent particle growth and reduction of the shell refractive index can be observed as red and blueshift behavior of the WGM, respectively. The shift pattern can be attributed to a core-shell radius ratio and particle radius derived from model calculations [2]. If supplemented with growth information obtained from the WGM redshift and thermodynamic equilibrium data, we can infer a comprehensive picture of the time evolution of the diffusion fronts in the framework of our core-shell model. The measured time dependent concentration profile is then compared with simulations solving the non-linear diffusion equation [3] [1] Virtanen, A., et al., Nature, 467, 824-827, 2010 [2] Kaiser, T., Schweiger, G., Computers in Physics, Vol. 7, No. 6, 682-686, Nov/Dec 1993 [3] Zobrist, B., Soonsin, V., Luo, B.P., Peter, T. et al., Phys. Chem. Chem

  17. A multi-parametric particle-pairing algorithm for particle tracking in single and multiphase flows

    International Nuclear Information System (INIS)

    Multiphase flows (MPFs) offer a rich area of fundamental study with many practical applications. Examples of such flows range from the ingestion of foreign particulates in gas turbines to transport of particles within the human body. Experimental investigation of MPFs, however, is challenging, and requires techniques that simultaneously resolve both the carrier and discrete phases present in the flowfield. This paper presents a new multi-parametric particle-pairing algorithm for particle tracking velocimetry (MP3-PTV) in MPFs. MP3-PTV improves upon previous particle tracking algorithms by employing a novel variable pair-matching algorithm which utilizes displacement preconditioning in combination with estimated particle size and intensity to more effectively and accurately match particle pairs between successive images. To improve the method's efficiency, a new particle identification and segmentation routine was also developed. Validation of the new method was initially performed on two artificial data sets: a traditional single-phase flow published by the Visualization Society of Japan (VSJ) and an in-house generated MPF data set having a bi-modal distribution of particles diameters. Metrics of the measurement yield, reliability and overall tracking efficiency were used for method comparison. On the VSJ data set, the newly presented segmentation routine delivered a twofold improvement in identifying particles when compared to other published methods. For the simulated MPF data set, measurement efficiency of the carrier phases improved from 9% to 41% for MP3-PTV as compared to a traditional hybrid PTV. When employed on experimental data of a gas–solid flow, the MP3-PTV effectively identified the two particle populations and reported a vector efficiency and velocity measurement error comparable to measurements for the single-phase flow images. Simultaneous measurement of the dispersed particle and the carrier flowfield velocities allowed for the calculation of

  18. Particle tracking and map analysis for compact storage rings

    International Nuclear Information System (INIS)

    Particle tracking codes for large storage rings approximate the Hamiltonian by neglecting terms of order x/ρ and higher. For storage rings with small bending radius magnets like the Super Conducting X-ray Lithography Source (SXLS), which make use of combined function bending magnets, these approximations cannot be made. The authors use an explicit symplectic integrator to construct a tracking code which uses the exact Hamiltonian for drifts and isomagnetic combined function bending magnets, in a manner similar to the Teapot code. Hard edge fringe fields are included in a symplectic manner for dipoles and quadrupoles. The integrator is coupled to the DA package of Berz to provide an arbitrary order map which can be analyzed using the tools of Forest and Irwin. A discussion of the techniques and an application to the SXLS ring at Brookhaven is presented

  19. Particle tracking with a Timepix based triple GEM detector

    International Nuclear Information System (INIS)

    This paper details the response of a triple GEM detector with a 55 μmetre pitch pixelated ASIC for readout. The detector is operated as a micro TPC with 9.5 cm3 sensitive volume and characterized with a mixed beam of 120 GeV protons and positive pions. A process for reconstruction of incident particle tracks from individual ionization clusters is described and scans of the gain and drift fields are performed. The angular resolution of the measured tracks is characterized. Also, the readout was operated in a mixed mode where some pixels measure drift time and others charge. This was used to measure the energy deposition in the detector and the charge cloud size as a function of interaction depth. The future uses of the device, including in microdosimetry are discussed

  20. 3D imaging of particle tracks in Solid State Nuclear Track Detectors

    Science.gov (United States)

    Wertheim, D.; Gillmore, G.; Brown, L.; Petford, N.

    2009-04-01

    Inhalation of radon gas (222Rn) and associated ionizing decay products is known to cause lung cancer in human. In the U.K., it has been suggested that 3 to 5 % of total lung cancer deaths can be linked to elevated radon concentrations in the home and/or workplace. Radon monitoring in buildings is therefore routinely undertaken in areas of known risk. Indeed, some organisations such as the Radon Council in the UK and the Environmental Protection Agency in the USA, advocate a ‘to test is best' policy. Radon gas occurs naturally, emanating from the decay of 238U in rock and soils. Its concentration can be measured using CR?39 plastic detectors which conventionally are assessed by 2D image analysis of the surface; however there can be some variation in outcomes / readings even in closely spaced detectors. A number of radon measurement methods are currently in use (for examples, activated carbon and electrets) but the most widely used are CR?39 solid state nuclear track?etch detectors (SSNTDs). In this technique, heavily ionizing alpha particles leave tracks in the form of radiation damage (via interaction between alpha particles and the atoms making up the CR?39 polymer). 3D imaging of the tracks has the potential to provide information relating to angle and energy of alpha particles but this could be time consuming. Here we describe a new method for rapid high resolution 3D imaging of SSNTDs. A ‘LEXT' OLS3100 confocal laser scanning microscope was used in confocal mode to successfully obtain 3D image data on four CR?39 plastic detectors. 3D visualisation and image analysis enabled characterisation of track features. This method may provide a means of rapid and detailed 3D analysis of SSNTDs. Keywords: Radon; SSNTDs; confocal laser scanning microscope; 3D imaging; LEXT

  1. Distributed Particle Filter for Target Tracking: With Reduced Sensor Communications.

    Science.gov (United States)

    Ghirmai, Tadesse

    2016-01-01

    For efficient and accurate estimation of the location of objects, a network of sensors can be used to detect and track targets in a distributed manner. In nonlinear and/or non-Gaussian dynamic models, distributed particle filtering methods are commonly applied to develop target tracking algorithms. An important consideration in developing a distributed particle filtering algorithm in wireless sensor networks is reducing the size of data exchanged among the sensors because of power and bandwidth constraints. In this paper, we propose a distributed particle filtering algorithm with the objective of reducing the overhead data that is communicated among the sensors. In our algorithm, the sensors exchange information to collaboratively compute the global likelihood function that encompasses the contribution of the measurements towards building the global posterior density of the unknown location parameters. Each sensor, using its own measurement, computes its local likelihood function and approximates it using a Gaussian function. The sensors then propagate only the mean and the covariance of their approximated likelihood functions to other sensors, reducing the communication overhead. The global likelihood function is computed collaboratively from the parameters of the local likelihood functions using an average consensus filter or a forward-backward propagation information exchange strategy. PMID:27618057

  2. Particle tracking code of simulating global RF feedback

    International Nuclear Information System (INIS)

    It is well known in the ''control community'' that a good feedback controller design is deeply rooted in the physics of the system. For example, when accelerating the beam we must keep several parameters under control so that the beam travels within the confined space. Important parameters include the frequency and phase of the rf signal, the dipole field, and the cavity voltage. Because errors in these parameters will progressively mislead the beam from its projected path in the tube, feedback loops are used to correct the behavior. Since the feedback loop feeds energy to the system, it changes the overall behavior of the system and may drive it to instability. Various types of controllers are used to stabilize the feedback loop. Integrating the beam physics with the feedback controllers allows us to carefully analyze the beam behavior. This will not only guarantee optimal performance but will also significantly enhance the ability of the beam control engineer to deal effectively with the interaction of various feedback loops. Motivated by this theme, we developed a simple one-particle tracking code to simulate particle behavior with feedback controllers. In order to achieve our fundamental objective, we can ask some key questions: What are the input and output parameters? How can they be applied to the practical machine? How can one interface the rf system dynamics such as the transfer characteristics of the rf cavities and phasing between the cavities? Answers to these questions can be found by considering a simple case of a single cavity with one particle, tracking it turn-by-turn with appropriate initial conditions, then introducing constraints on crucial parameters. Critical parameters are rf frequency, phase, and amplitude once the dipole field has been given. These are arranged in the tracking code so that we can interface the feedback system controlling them

  3. Nuclear particle track-etched anti-bogus mark

    International Nuclear Information System (INIS)

    Nuclear particle track-etched anti-bogus mark is a new type of forgery-proof product after engraving gravure printing, thermocolour, fluorescence, laser hologram and metal concealed anti-bogus mark. The mark is manufactured by intricate high technology and the state strictly controlled sensitive nuclear facilities to ensure the mark not to be copied. The pattern of the mark is specially characterized by permeability of liquid to be discriminated from forgery. The genuine mark can be distinguished from sham one by transparent liquid (e.g. water), colorful pen and chemical reagent. The mark has passed the official examination of health safety. It is no danger of nuclear irradiation. (author)

  4. Single particle tracking and single molecule energy transfer

    CERN Document Server

    Bräuchle, Christoph; Michaelis, Jens

    2009-01-01

    Closing a gap in the literature, this handbook gathers all the information on single particle tracking and single molecule energy transfer. It covers all aspects of this hot and modern topic, from detecting virus entry to membrane diffusion, and from protein folding using spFRET to coupled dye systems, as well recent achievements in the field. Throughout, the first-class editors and top international authors present content of the highest quality, making this a must-have for physical chemists, spectroscopists, molecular physicists and biochemists.

  5. Inversely tracking indoor airborne particles to locate their release sources

    Science.gov (United States)

    Zhang, Tengfei (Tim); Li, Hongzhu; Wang, Shugang

    2012-08-01

    Airborne particles can have numerous adverse effects on human health. Knowing the release locations of airborne particulate sources is helpful in minimizing pollutant exposure. This paper describes a proposal to locate indoor particulate sources by two inverse models: the quasi-reversibility (QR) model and the zone prescription of contaminant sources with the Lagrangian-reversibility (LR) model. The QR model reverses the time marching direction of the Eulerian governing equation and replaces the second-order diffusion term with a fourth-order stabilization term. The zone prescription LR model traces individual particulate motion in a Lagrangian reference frame after reversing the flow field. The particle trajectories are solved backward to the initial release once the conservative forces acting on particles are reversed. The tracked particles are proposed to be placed at the zone boundary of the largest concentration contour within the domain at a given time, which is provided as the initially known information. By connecting all particles at t = 0, a zone is formed that can prescribe the actual contaminant source. This study finds that both models can accurately locate particulate sources released instantaneously at a spot. The QR model performs slightly better than the LR model but is much more computationally demanding.

  6. A 3D diamond detector for particle tracking

    International Nuclear Information System (INIS)

    A novel device using single-crystal chemical vapour deposited diamond and resistive electrodes in the bulk forming a 3D diamond detector is presented. The electrodes of the device were fabricated with laser assisted phase change of diamond into a combination of diamond-like carbon, amorphous carbon and graphite. The connections to the electrodes of the device were made using a photo-lithographic process. The electrical and particle detection properties of the device were investigated. A prototype detector system consisting of the 3D device connected to a multi-channel readout was successfully tested with 120 GeV protons proving the feasibility of the 3D diamond detector concept for particle tracking applications for the first time

  7. Modeling reactive transport with particle tracking and kernel estimators

    Science.gov (United States)

    Rahbaralam, Maryam; Fernandez-Garcia, Daniel; Sanchez-Vila, Xavier

    2015-04-01

    Groundwater reactive transport models are useful to assess and quantify the fate and transport of contaminants in subsurface media and are an essential tool for the analysis of coupled physical, chemical, and biological processes in Earth Systems. Particle Tracking Method (PTM) provides a computationally efficient and adaptable approach to solve the solute transport partial differential equation. On a molecular level, chemical reactions are the result of collisions, combinations, and/or decay of different species. For a well-mixed system, the chem- ical reactions are controlled by the classical thermodynamic rate coefficient. Each of these actions occurs with some probability that is a function of solute concentrations. PTM is based on considering that each particle actually represents a group of molecules. To properly simulate this system, an infinite number of particles is required, which is computationally unfeasible. On the other hand, a finite number of particles lead to a poor-mixed system which is limited by diffusion. Recent works have used this effect to actually model incomplete mix- ing in naturally occurring porous media. In this work, we demonstrate that this effect in most cases should be attributed to a defficient estimation of the concentrations and not to the occurrence of true incomplete mixing processes in porous media. To illustrate this, we show that a Kernel Density Estimation (KDE) of the concentrations can approach the well-mixed solution with a limited number of particles. KDEs provide weighting functions of each particle mass that expands its region of influence, hence providing a wider region for chemical reactions with time. Simulation results show that KDEs are powerful tools to improve state-of-the-art simulations of chemical reactions and indicates that incomplete mixing in diluted systems should be modeled based on alternative conceptual models and not on a limited number of particles.

  8. Sequential Bearings-Only-Tracking Initiation with Particle Filtering Method

    Directory of Open Access Journals (Sweden)

    Bin Liu

    2013-01-01

    Full Text Available The tracking initiation problem is examined in the context of autonomous bearings-only-tracking (BOT of a single appearing/disappearing target in the presence of clutter measurements. In general, this problem suffers from a combinatorial explosion in the number of potential tracks resulted from the uncertainty in the linkage between the target and the measurement (a.k.a the data association problem. In addition, the nonlinear measurements lead to a non-Gaussian posterior probability density function (pdf in the optimal Bayesian sequential estimation framework. The consequence of this nonlinear/non-Gaussian context is the absence of a closed-form solution. This paper models the linkage uncertainty and the nonlinear/non-Gaussian estimation problem jointly with solid Bayesian formalism. A particle filtering (PF algorithm is derived for estimating the model’s parameters in a sequential manner. Numerical results show that the proposed solution provides a significant benefit over the most commonly used methods, IPDA and IMMPDA. The posterior Cramér-Rao bounds are also involved for performance evaluation.

  9. Shake-The-Box: Lagrangian particle tracking at high particle image densities

    Science.gov (United States)

    Schanz, Daniel; Gesemann, Sebastian; Schröder, Andreas

    2016-05-01

    A Lagrangian tracking method is introduced, which uses a prediction of the particle distribution for the subsequent time-step as a mean to seize the temporal domain. Errors introduced by the prediction process are corrected by an image matching technique (`shaking' the particle in space), followed by an iterative triangulation of particles newly entering the measurement domain. The scheme was termed `Shake-The-Box' and previously characterized as `4D-PTV' due to the strong interaction with the temporal dimension. Trajectories of tracer particles are identified at high spatial accuracy due to a nearly complete suppression of ghost particles; a temporal filtering scheme further improves on accuracy and allows for the extraction of local velocity and acceleration as derivatives of a continuous function. Exploiting the temporal information enables the processing of densely seeded flows (beyond 0.1 particles per pixel, ppp), which were previously reserved for tomographic PIV evaluations. While TOMO-PIV uses statistical means to evaluate the flow (building an `anonymous' voxel space with subsequent spatial averaging of the velocity information using correlation), the Shake-The-Box approach is able to identify and track individual particles at numbers of tens or even hundreds of thousands per time-step. The method is outlined in detail, followed by descriptions of applications to synthetic and experimental data. The synthetic data evaluation reveals that STB is able to capture virtually all true particles, while effectively suppressing the formation of ghost particles. For the examined four-camera set-up particle image densities N I up to 0.125 ppp could be processed. For noise-free images, the attained accuracy is very high. The addition of synthetic noise reduces usable particle image density ( N I ≤ 0.075 ppp for highly noisy images) and accuracy (still being significantly higher compared to tomographic reconstruction). The solutions remain virtually free of ghost

  10. Optimization of detector positioning in the radioactive particle tracking technique

    International Nuclear Information System (INIS)

    The radioactive particle tracking (RPT) technique is a non-intrusive experimental velocimetry and tomography technique extensively applied to the study of hydrodynamics in a great variety of systems. In this technique, arrays of scintillation detector are used to track the motion of a single radioactive tracer particle emitting isotropic γ-rays. This work describes and applies an optimization strategy developed to find an optimal set of positions for the scintillation detectors used in the RPT technique. This strategy employs the overall resolution of the detectors as the objective function and a mesh adaptive direct search (MADS) algorithm to solve the optimization problem. More precisely, NOMAD, a C++ implementation of the MADS algorithm is used. First, the optimization strategy is validated using simple cases with known optimal detector configurations. Next, it is applied to a three-dimensional axisymmetric system (i.e. a vertical cylinder, which could represent a fluidized bed, bubble column, riser or else). The results obtained using the optimization strategy are in agreement with what was previously recommended by Roy et al. (2002) for a similar system. Finally, the optimization strategy is used for a system consisting of a partially filled cylindrical tumbler. The application of insights gained by the optimization strategy is shown to lead to a significant reduction in the error made when reconstructing the position of a tracer particle. The results of this work show that the optimization strategy developed is sensitive to both the type of objective function used and the experimental conditions. The limitations and drawbacks of the optimization strategy are also discussed. - Highlights: • A strategy to determine the optimal position of detectors for RPT. • Optimization results are specific to the objective function. • Optimization results are specific to the experimental conditions. • The strategy can help determine the minimum number of detector to

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

    Directory of Open Access Journals (Sweden)

    Hoffmann Alex C.

    2013-05-01

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

  12. Theory of heavy charged particle thermoluminescence response: the extended track interaction model

    International Nuclear Information System (INIS)

    The theory of heavy charged particle TL response is described in the framework of the extended track interaction model which includes an enhanced understanding of the role/parameters of the individual track (i.e. the track structure) which influence the track interaction effects, a more sophisticated treatment of track interaction effects as well as a revised analytical treatment of saturation effects based on knowledge of the dose-filling constants of the TCs and LCs. (author)

  13. SSCTRK: A particle tracking code for the SSC

    International Nuclear Information System (INIS)

    While many indirect methods are available to evaluate dynamic aperture there appears at this time to be no reliable substitute to tracking particles through realistic machine lattices for a number of turns determined by the storage times. Machine lattices are generated by ''Monte Carlo'' techniques from the expected rms fabrication and survey errors. Any given generated machine can potentially be a lucky or unlucky fluctuation from the average. Therefore simulation to serve as a predictor of future performance must be done for an ensemble of generated machines. Further, several amplitudes and momenta are necessary to predict machine performance. Thus to make Monte Carlo type simulations for the SSC requires very considerable computer resources. Hitherto, it has been assumed that this was not feasible, and alternative indirect methods have been proposed or tried to answer the problem. We reexamined the feasibility of using direct computation. Previous codes have represented lattices by a succession of thin elements separated by bend-drifts. With ''kick-drift'' configurations, tracking time is linear in the multipole order included, and the code is symplectic. Modern vector processors simultaneously handle a large number of cases in parallel. Combining the efficiencies of kick drift tracking with vector processing, in fact, makes realistic Monte Carlo simulation entirely feasible. SSCTRK uses the above features. It is structured to have a very friendly interface, a very wide latitude of choice for cases to be run in parallel, and, by using pure FORTRAN 77, to interchangeably run on a wide variety of computers. We describe in this paper the program structure operational checks and results achieved

  14. Real-Time Particle Tracking for Studying Intracellular Trafficking of Pharmaceutical Nanocarriers

    OpenAIRE

    Huang, Feiran; Watson, Erin; Dempsey, Christopher; Suh, Junghae

    2013-01-01

    Real-time particle tracking is a technique that combines fluorescence microscopy with object tracking and computing and can be used to extract quantitative transport parameters for small particles inside cells. Since the success of a nanocarrier can often be determined by how effectively it delivers cargo to the target organelle, understanding the complex intracellular transport of pharmaceutical nanocarriers is critical. Real-time particle tracking provides insight into the dynamics of the i...

  15. Steady-state particle tracking in the object-oriented regional groundwater model ZOOMQ3D

    OpenAIRE

    Jackson, C.R.

    2002-01-01

    This report describes the development of a steady-state particle tracking code for use in conjunction with the object-oriented regional groundwater flow model, ZOOMQ3D (Jackson, 2001). Like the flow model, the particle tracking software, ZOOPT, is written using an object-oriented approach to promote its extensibility and flexibility. ZOOPT enables the definition of steady-state pathlines in three dimensions. Particles can be tracked in both the forward and reverse directions en...

  16. Beam dynamics calculations and particle tracking using massively parallel processors

    International Nuclear Information System (INIS)

    During the past decade massively parallel processors (MPPs) have slowly gained acceptance within the scientific community. At present these machines typically contain a few hundred to one thousand off-the-shelf microprocessors and a total memory of up to 32 GBytes. The potential performance of these machines is illustrated by the fact that a month long job on a high end workstation might require only a few hours on an MPP. The acceptance of MPPs has been slow for a variety of reasons. For example, some algorithms are not easily parallelizable. Also, in the past these machines were difficult to program. But in recent years the development of Fortran-like languages such as CM Fortran and High Performance Fortran have made MPPs much easier to use. In the following we will describe how MPPs can be used for beam dynamics calculations and long term particle tracking

  17. Color-based tracking of plasma dust particles

    Energy Technology Data Exchange (ETDEWEB)

    Villamayor, Michelle Marie S., E-mail: mvillamayor@nip.upd.edu.ph; Soriano, Maricor N.; Ramos, Henry J. [National Institute of Physics, University of the Philippines, Diliman, Quezon City 1101 (Philippines); Kato, Shuichi; Wada, Motoi [Graduate School of Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan)

    2014-02-15

    Color-based tracking to observe agglomeration of deposited particles inside a compact planar magnetron during plasma discharge was done by creating high dynamic range (HDR) images of photos captured by a Pentax K10D digital camera. Carbon erosion and redeposition was also monitored using the technique. The HDR images were subjected to a chromaticity-based constraint discoloration inside the plasma chamber indicating film formation or carbon redeposition. Results show that dust deposition occurs first near the evacuation pumps due to the pressure gradient and then accumulates at the positively charged walls of the chamber. This method can be applied to monitor dust formation during dusty plasma experiments without major modification of plasma devices, useful especially for large fusion reactors.

  18. Robust and Adaptive Block Tracking Method Based on Particle Filter

    Directory of Open Access Journals (Sweden)

    Bin Sun

    2015-10-01

    Full Text Available In the field of video analysis and processing, object tracking is attracting more and more attention especially in traffic management, digital surveillance and so on. However problems such as objects’ abrupt motion, occlusion and complex target structures would bring difficulties to academic study and engineering application. In this paper, a fragmentsbased tracking method using the block relationship coefficient is proposed. In this method, we use particle filter algorithm and object region is divided into blocks initially. The contribution of this method is that object features are not extracted just from a single block, the relationship between current block and its neighbor blocks are extracted to describe the variation of the block. Each block is weighted according to the block relationship coefficient when the block is voted on the most matched region in next frame. This method can make full use of the relationship between blocks. The experimental results demonstrate that our method can provide good performance in condition of occlusion and abrupt posture variation.

  19. 3D measurement of the position of gold particles via evanescent digital holographic particle tracking velocimetry

    Science.gov (United States)

    Satake, Shin-ichi; Unno, Noriyuki; Nakata, Shuichiro; Taniguchi, Jun

    2016-08-01

    A new technique based on digital holography and evanescent waves was developed for 3D measurements of the position of gold nanoparticles in water. In this technique, an intensity profile is taken from a holographic image of a gold particle. To detect the position of the gold particle with high accuracy, its holographic image is recorded on a nanosized step made of MEXFLON, which has a refractive index close to that of water, and the position of the particle is reconstructed by means of digital holography. The height of the nanosized step was measured by using a profilometer and the digitally reconstructed height of the glass substrate had good agreement with the measured value. Furthermore, this method can be used to accurately track the 3D position of a gold particle in water.

  20. On the calibration of astigmatism particle tracking velocimetry for microflows

    International Nuclear Information System (INIS)

    Astigmatism particle tracking velocimetry (APTV) is a method to determine three components (3C) of the velocity field in a volume (3D) using a single camera. The depth position of the particles is coded by optical distortions caused by a cylindrical lens in the optical setup. This technique is particularly suited for microfluidic applications as measurement errors due to spatial averaging and depth of correlation, typically encountered with μPIV approaches, are eliminated so that the measurement precision is enhanced. Unfortunately, the current state of the technique is limited by the small measurement region achievable with the current calibration procedures as well as by higher order image aberrations (Cierpka et al 2010 Meas. Sci. Technol. 21 045401). In order to extend the size of the measurement volume and to account for all image aberrations, a new intrinsic calibration procedure, based on the imaging function of the particles, is proposed in the paper at hand. It provides an extended measurement depth, taking into account all image aberrations. In this work, the calibration procedure was applied to a μPIV arrangement but could also be implemented on macroscopic experimental setups. The calibration procedure is qualified with synthetic data as well as Poiseuille flow in a straight rectangular micro-channel with a cross-sectional area of 200 ×  500 µm2. The three-dimensional velocity distribution of the whole channel was resolved via APTV with uncertainties of 0.9% and 3.7% of the centerline velocity, uc, for the in-plane and out-of-plane components, respectively. Further investigations using different cylindrical-lens focal lengths, magnifications and particle sizes provide information about achievable measurement depths and help to design and adapt the optimal system for the desired experiment

  1. On the calibration of astigmatism particle tracking velocimetry for microflows

    Science.gov (United States)

    Cierpka, C.; Rossi, M.; Segura, R.; Kähler, C. J.

    2011-01-01

    Astigmatism particle tracking velocimetry (APTV) is a method to determine three components (3C) of the velocity field in a volume (3D) using a single camera. The depth position of the particles is coded by optical distortions caused by a cylindrical lens in the optical setup. This technique is particularly suited for microfluidic applications as measurement errors due to spatial averaging and depth of correlation, typically encountered with μPIV approaches, are eliminated so that the measurement precision is enhanced. Unfortunately, the current state of the technique is limited by the small measurement region achievable with the current calibration procedures as well as by higher order image aberrations (Cierpka et al 2010 Meas. Sci. Technol. 21 045401). In order to extend the size of the measurement volume and to account for all image aberrations, a new intrinsic calibration procedure, based on the imaging function of the particles, is proposed in the paper at hand. It provides an extended measurement depth, taking into account all image aberrations. In this work, the calibration procedure was applied to a μPIV arrangement but could also be implemented on macroscopic experimental setups. The calibration procedure is qualified with synthetic data as well as Poiseuille flow in a straight rectangular micro-channel with a cross-sectional area of 200 × 500 µm2. The three-dimensional velocity distribution of the whole channel was resolved via APTV with uncertainties of 0.9% and 3.7% of the centerline velocity, uc, for the in-plane and out-of-plane components, respectively. Further investigations using different cylindrical-lens focal lengths, magnifications and particle sizes provide information about achievable measurement depths and help to design and adapt the optimal system for the desired experiment.

  2. Monte Carlo N-Particle Tracking of Ultrafine Particle Flow in Bent Micro-Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Casella, Andrew M.; Loyalka, Sudarsham K.

    2016-02-16

    The problem of large pressure-differential driven laminar convective-diffusive ultrafine aerosol flow through bent micro-tubes is of interest in several contemporary research areas including; release of contents from pressurized containment vessels, aerosol sampling equipment, advanced scientific instruments, gas-phase micro-heat exchangers, and microfluidic devices. In each of these areas, the predominant problem is the determination of the fraction of particles entering the micro-tube that is deposited within the tube and the fraction that is transmitted through. Due to the extensive parameter restrictions of this class of problems, a Lagrangian particle tracking method making use of the coupling of the analytical stream line solutions of Dean and the simplified Langevin equation is quite a useful tool in problem characterization. This method is a direct analog to the Monte Carlo N-Particle method of particle transport extensively used in nuclear physics and engineering. In this work, 10 nm diameter particles with a density of 1 g/cm3 are tracked within micro-tubes with toroidal bends with pressure differentials ranging between 0.2175 and 0.87 atmospheres. The tubes have radii of 25 microns and 50 microns and the radius of curvature is between 1 m and 0.3183 cm. The carrier gas is helium, and temperatures of 298 K and 558 K are considered. Numerical convergence is considered as a function of time step size and of the number of particles per simulation. Particle transmission rates and deposition patterns within the bent micro-tubes are calculated.

  3. Particle image velocimetry for the Surface Tension Driven Convection Experiment using a particle displacement tracking technique

    Science.gov (United States)

    Wernet, Mark P.; Pline, Alexander D.

    1991-01-01

    The Surface Tension Driven Convection Experiment (STDCE) is a Space Transportation System flight experiment to study both transient and steady thermocapillary fluid flows aboard the USML-1 Spacelab mission planned for 1992. One of the components of data collected during the experiment is a video record of the flow field. This qualitative data is then quantified using an all electronic, two-dimensional particle image velocimetry technique called particle displacement tracking (PDT) which uses a simple space domain particle tracking algorithm. The PDT system is successful in producing velocity vector fields from the raw video data. Application of the PDT technique to a sample data set yielded 1606 vectors in 30 seconds of processing time. A bottom viewing optical arrangement is used to image the illuminated plane, which causes keystone distortion in the final recorded image. A coordinate transformation was incorporated into the system software to correct this viewing angle distortion. PDT processing produced 1.8 percent false identifications, due to random particle locations. A highly successful routine for removing the false identifications was also incorporated, reducing the number of false identifications to 0.2 percent.

  4. Study on Multi-Target Tracking Based on Particle Filter Algorithm

    OpenAIRE

    Junying Meng; Jiaomin Liu; Yongzheng Li; Juan Wang

    2013-01-01

    Particle filter is a probability estimation method based on Bayesian framework and it has unique advantage to describe the target tracking non-linear and non-Gaussian. In this study, firstly, analyses the particle degeneracy and sample impoverishment in particle filter multi-target tracking algorithm and secondly, it applies Markov Chain Monte Carlo (MCMC) method to improve re-sampling process and enhance performance of particle filter algorithm.

  5. VOLTAGE REGULATORS ASYNCHRONOUS GENERATORS

    OpenAIRE

    Grigorash O. V.; Bogatyrev N. I.; Hitskova A. O.

    2015-01-01

    A promising is currently the use of asynchronous generators with capacitive excitation as a source of electricity in stand-alone power systems. Drive asynchronous generators may exercise as a thermal engine and wind wheel wind power plant or turbines of small hydropower plants. The article discusses the structural and schematics of voltage stabilizers and frequency of asynchronous generators with improved operational and technical specifications. Technical novelty of design solutions of the m...

  6. Multi-color single particle tracking with quantum dots.

    Directory of Open Access Journals (Sweden)

    Eva C Arnspang

    Full Text Available Quantum dots (QDs have long promised to revolutionize fluorescence detection to include even applications requiring simultaneous multi-species detection at single molecule sensitivity. Despite the early promise, the unique optical properties of QDs have not yet been fully exploited in e. g. multiplex single molecule sensitivity applications such as single particle tracking (SPT. In order to fully optimize single molecule multiplex application with QDs, we have in this work performed a comprehensive quantitative investigation of the fluorescence intensities, fluorescence intensity fluctuations, and hydrodynamic radii of eight types of commercially available water soluble QDs. In this study, we show that the fluorescence intensity of CdSe core QDs increases as the emission of the QDs shifts towards the red but that hybrid CdSe/CdTe core QDs are less bright than the furthest red-shifted CdSe QDs. We further show that there is only a small size advantage in using blue-shifted QDs in biological applications because of the additional size of the water-stabilizing surface coat. Extending previous work, we finally also show that parallel four color multicolor (MC-SPT with QDs is possible at an image acquisition rate of at least 25 Hz. We demonstrate the technique by measuring the lateral dynamics of a lipid, biotin-cap-DPPE, in the cellular plasma membrane of live cells using four different colors of QDs; QD565, QD605, QD655, and QD705 as labels.

  7. Experiments with nuclear track detectors for diagnostics of protons and alpha particles from fusion plasmas

    International Nuclear Information System (INIS)

    This report deals with the experimental development of a method of detecting charged particles from nuclear fusion plasmas by means of nuclear track detectors. The latter were bombarded with protons and alpha particles poduced with an accelerator from the fusion reactions D (3He, p) α and D (D, p) T. In the parameter range expected for the particles emitted from thermonuclearly burning plasma the detection probabilities of protons and alpha particles were determined as functions of the energy and angle of incidence, and also the crater radii and depths as functions of the particle species, particle energy and etching time. The following results were obtained: For alpha particles the detection probability in the entire energy range investigated and at angles of incidence between 00 and 700 to the foil normal is about 100%. The alpha particle energy can be approximately determined from the track depths. For protons, on the other hand, the detection probability already decreases monotonically at low energies as the energy increases, becoming zero at about Esub(p) = 7 MeV. Proton detection is only possible at angles of incidence between 00 and 300. The proton energy can be approximately determined from the track radii. The measured energy dependence of the track radii and depths of alpha particles and protons and their angular dependence can be explained with a simple model calculation in which it is assumed that the track etching rate decreases as the particle range in the material of the nuclear track foils increases. (orig.)

  8. Digital characterization of recoil charged-particle tracks for neutron measurements

    International Nuclear Information System (INIS)

    We are developing a new optical ionization detector for imaging the track of a charged neutron-recoil particle in a gas. Electrons produced in the path of the recoil particle are excited by an external, high-voltage, RF, electric field of short duration. Their oscillatory motion causes ionization and excitation of nearby gas molecules, which then emit light in subsequent de-excitation. Two digital cameras image the optical radiation across two perpendicular planes and analyze it for the numbers of electrons in various volume elements along the track. These numbers constitute the digital characterization of the track. This information can then be used to infer the energy deposited in the track and the track LET in the gas. We have now observed alpha-particle tracks in a chamber utilizing these principles. The application of such a device for neutron dosimetry and neutron spectrometry will be described. 4 refs., 3 figs

  9. Digital characterization of recoil charged-particle tracks for neutron measurements

    International Nuclear Information System (INIS)

    We are developing a new optical ionization detector for imaging the track of a charged neutron-recoil particle in a gas. Electrons produced in the path of the recoil particle are excited by an external, high-voltage, rf, electric field of short duration. Their oscillatory motion causes ionization and excitation of nearby gas molecules, which then emit light in subsequent de-excitation. Two digital cameras image the optical radiation across two perpendicular planes and analyze it for the numbers of electrons in various volume elements along the track. These numbers constitute the digital characterization of the track. This information can then be used to infer the energy deposited in the track and the track LET in the gas. We have now observed alpha-particle tracks in a chamber utilizing these principles. The application of such a device for neutron dosimetry and neuron spectrometry will be described. (orig.)

  10. Particle Tracking Model and Abstraction of Transport Processes

    International Nuclear Information System (INIS)

    The purpose of this report is to document the abstraction model being used in total system performance assessment (TSPA) model calculations for radionuclide transport in the unsaturated zone (UZ). The UZ transport abstraction model uses the particle-tracking method that is incorporated into the finite element heat and mass model (FEHM) computer code (Zyvoloski et al. 1997 [DIRS 100615]) to simulate radionuclide transport in the UZ. This report outlines the assumptions, design, and testing of a model for calculating radionuclide transport in the UZ at Yucca Mountain. In addition, methods for determining and inputting transport parameters are outlined for use in the TSPA for license application (LA) analyses. Process-level transport model calculations are documented in another report for the UZ (BSC 2004 [DIRS 164500]). Three-dimensional, dual-permeability flow fields generated to characterize UZ flow (documented by BSC 2004 [DIRS 169861]; DTN: LB03023DSSCP9I.001 [DIRS 163044]) are converted to make them compatible with the FEHM code for use in this abstraction model. This report establishes the numerical method and demonstrates the use of the model that is intended to represent UZ transport in the TSPA-LA. Capability of the UZ barrier for retarding the transport is demonstrated in this report, and by the underlying process model (BSC 2004 [DIRS 164500]). The technical scope, content, and management of this report are described in the planning document ''Technical Work Plan for: Unsaturated Zone Transport Model Report Integration'' (BSC 2004 [DIRS 171282]). Deviations from the technical work plan (TWP) are noted within the text of this report, as appropriate. The latest version of this document is being prepared principally to correct parameter values found to be in error due to transcription errors, changes in source data that were not captured in the report, calculation errors, and errors in interpretation of source data

  11. Track before detect for point targets with particle filter in infrared image sequences

    Institute of Scientific and Technical Information of China (English)

    Hongtao Hu; Zhongliang Jing; Shiqiang Hu

    2005-01-01

    @@ The problem of detecting and tracking point targets in a sequence of infrared images with very low signalto-noise ratio (SNR) is investigated in this paper. A track before detect algorithm for infrared (IR) point target is developed based on particle filter. The particle filter is used to estimate the state of the target in track stage. The unnormalized weights of the output of the filter are used to approximately construct the likelihood ratio for hypothesis test in detection stage. Experiment results with the real image sequences that SNR is about 2.0 show that the proposed algorithm can successfully detect and track point target.

  12. Compositional asynchronous membrane systems

    Institute of Scientific and Technical Information of China (English)

    Cosmin Bonchis; Cornel Izbasa; Gabriel Ciobanu

    2007-01-01

    This paper presents an algorithmic way of building complex membrane systems by coupling elementary membranes. Its application seems particularly valuable in the case of asynchronous membrane systems, since the resulting membrane system remains asynchronous. The composition method is based on a handshake mechanism implemented by using antiport rules and promoters.

  13. 3D particle tracking velocimetry using dynamic discrete tomography for plasma physics applications

    DEFF Research Database (Denmark)

    Moseev, Dmitry; Alpers, Andreas; Gritzmann, Peter;

    2013-01-01

    3D particle tracking velocimetry (PTV) is a diagnostic technique which is widely used for studying flows, combustion, and plasmas. Current tomographic particle tracking methods are based on the multiplicative algebraic reconstruction technique and used for reconstructing the distribution of multi......-pixel sized particles as greylevel images. Reconstructions obtained by these methods do not necessarily match the experimental data. We propose a new algorithm which can be used for tracking dust particles in tokamaks and stellarators, as well as in low-temperature and complex plasmas. The dynamic discrete...... tomography algorithm is efficient for data from two projection directions and exact. The non-uniqueness can be detected and tracked individually. The algorithm performance is proportional to N3 on average where N is the number of particles in the reconstruction. There is a room for further improvement of the...

  14. A new paradigm for particle tracking velocimetry, based on graph-theory and pulsed neural network

    International Nuclear Information System (INIS)

    The Particle Tracking Velocimetry (PTV) technique works by recording, at different instances in time, positions of small tracers particles following a flow and illuminated by a sheet, or pseudo sheet, of light. It aims to recognize each particle trajectory, constituted of n different spots and determine thus each particle velocity vector. In this paper, we devise a new method, taking into account a global consistency of the trajectories to be extracted, in terms of visual perception and physical properties. It is based on a graph-theoretic formulation of the particle tracking problem and the use of an original neural network, called pulsed neural network. (authors). 4 figs

  15. Improvement in Fast Particle Track Reconstruction with Robust Statistics

    DEFF Research Database (Denmark)

    Aartsen, M.G.; Abbasi, R.; Abdou, Y.;

    2014-01-01

    The IceCube project has transformed one cubic kilometer of deep natural Antarctic ice into a Cherenkov detector. Muon neutrinos are detected and their direction inferred by mapping the light produced by the secondary muon track inside the volume instrumented with photomultipliers. Reconstructing...... the muon track from the observed light is challenging due to noise, light scattering in the ice medium, and the possibility of simultaneously having multiple muons inside the detector, resulting from the large flux of cosmic ray muons. This manuscript describes work on two problems: (1) the track...... reconstruction problem, in which, given a set of observations, the goal is to recover the track of a muon; and (2) the coincident event problem, which is to determine how many muons are active in the detector during a time window. Rather than solving these problems by developing more complex physical models that...

  16. An efficient Rao-Blackwellized particle filter for object tracking

    OpenAIRE

    Arnaud, Elise; Memin, Etienne

    2005-01-01

    International audience In this paper we present a technique for the tracking of textured almost planar object. The target is modeled as a noisy planar cloud of points. The tracking is led with an appropriate non linear stochastic filter. The particular system that we devised is conditionally Gaussian and can be efficiently implemented through variance reduction principle known as Rao-Blackwellisation. Our model allows also to melt a correlation measurements with dynamic model estimated fro...

  17. Neutron dosimetry using particle tracks in solids: an intercomparison

    International Nuclear Information System (INIS)

    Comparison of two nuclear track methods of dosimetry for fast neutrons shows similar uncertainties for manual counting of etched tracks as for electrochemical read-out by a commercial service. The standard deviation is approx. 30% under rigorous specification of conditions - i.e., monoenergetic neutrons and minimum neutron scattering. Because uncertainty of this magnitude or greater is common to most methods, such doses should not be quoted to higher precision. 16 references, 6 figures, 2 tables

  18. A particle-filtering approach to convoy tracking in the midst of civilian traffic

    Science.gov (United States)

    Pollard, Evangeline; Pannetier, Benjamin; Rombaut, Michèle

    2008-04-01

    In the battlefield surveillance domain, ground target tracking is used to evaluate the threat. Data used for tracking is given by a Ground Moving Target Indicator (GMTI) sensor which only detects moving targets. Multiple target tracking has been widely studied but most of the algorithms have weaknesses when targets are close together, as they are in a convoy. In this work, we propose a filtering approach for convoys in the midst of civilian traffic. Inspired by particle filtering, our specific algorithm cannot be applied to all the targets because of its complexity. That is why well discriminated targets are tracked using an Interacting Multiple Model-Multiple Hypothesis Tracking (IMM-MHT), whereas the convoy targets are tracked with a specific particle filter. We make the assumption that the convoy is detected (position and number of targets). Our approach is based on an Independent Partition Particle Filter (IPPF) incorporating constraint-regions. The originality of our approach is to consider a velocity constraint (all the vehicles belonging to the convoy have the same velocity) and a group constraint. Consequently, the multitarget state vector contains all the positions of the individual targets and a single convoy velocity vector. When another target is detected crossing or overtaking the convoy, a specific algorithm is used and the non-cooperative target is tracked down an adapted particle filter. As demonstrated by our simulations, a high increase in convoy tracking performance is obtained with our approach.

  19. Multiple Human Tracking Using Particle Filter with Gaussian Process Dynamical Model

    OpenAIRE

    Hong Man; Yafeng Yin; Jing Wang

    2008-01-01

    Abstract We present a particle filter-based multitarget tracking method incorporating Gaussian process dynamical model (GPDM) to improve robustness in multitarget tracking. With the particle filter Gaussian process dynamical model (PFGPDM), a high-dimensional target trajectory dataset of the observation space is projected to a low-dimensional latent space in a nonlinear probabilistic manner, which will then be used to classify object trajectories, predict the next motion state, and provide Ga...

  20. A SUNTANS-based unstructured grid local exact particle tracking model

    Science.gov (United States)

    Liu, Guangliang; Chua, Vivien P.

    2016-07-01

    A parallel particle tracking model, which employs the local exact integration method to achieve high accuracy, has been developed and embedded in an unstructured-grid coastal ocean model, Stanford Unstructured Nonhydrostatic Terrain-following Adaptive Navier-Stokes Simulator (SUNTANS). The particle tracking model is verified and compared with traditional numerical integration methods, such as Runge-Kutta fourth-order methods using several test cases. In two-dimensional linear steady rotating flow, the local exact particle tracking model is able to track particles along the circular streamline accurately, while Runge-Kutta fourth-order methods produce trajectories that deviate from the streamlines. In periodically varying double-gyre flow, the trajectories produced by local exact particle tracking model with time step of 1.0 × 10- 2 s are similar to those trajectories obtained from the numerical integration methods with reduced time steps of 1.0 × 10- 4 s. In three-dimensional steady Arnold-Beltrami-Childress (ABC) flow, the trajectories integrated with the local exact particle tracking model compares well with the approximated true path. The trajectories spiral upward and their projection on the x- y plane is a periodic ellipse. The trajectories derived with the Runge-Kutta fourth-order method deviate from the approximated true path, and their projections on the x- y plane are unclosed ellipses with growing long and short axes. The spatial temporal resolution needs to be carefully chosen before particle tracking models are applied. Our results show that the developed local exact particle tracking model is accurate and suitable for marine Lagrangian (trajectory-based)-related research.

  1. Passively Track WiFi Users with an Enhanced Particle Filter using Power-based Ranging

    OpenAIRE

    Li, Zan; Braun, Torsten

    2015-01-01

    Passive positioning systems produce user location information for third-party providers of positioning services. Since the tracked wireless devices do not participate in the positioning process, passive positioning can only rely on simple, measurable radio signal parameters, such as timing or power information. In this work, we provide a passive tracking system for WiFi signals with an enhanced particle filter using fine-grained power-based ranging. Our proposed particle filter provides an im...

  2. Improvement in fast particle track reconstruction with robust statistics

    Science.gov (United States)

    Aartsen, M. G.; Abbasi, R.; Abdou, Y.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Altmann, D.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Baum, V.; Bay, R.; Beatty, J. J.; Bechet, S.; Becker Tjus, J.; Becker, K.-H.; Benabderrahmane, M. L.; BenZvi, S.; Berghaus, P.; Berley, D.; Bernardini, E.; Bernhard, A.; Besson, D. Z.; Binder, G.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohaichuk, S.; Bohm, C.; Bose, D.; Böser, S.; Botner, O.; Brayeur, L.; Bretz, H.-P.; Brown, A. M.; Bruijn, R.; Brunner, J.; Carson, M.; Casey, J.; Casier, M.; Chirkin, D.; Christov, A.; Christy, B.; Clark, K.; Clevermann, F.; Coenders, S.; Cohen, S.; Cowen, D. F.; Cruz Silva, A. H.; Danninger, M.; Daughhetee, J.; Davis, J. C.; Day, M.; De Clercq, C.; De Ridder, S.; Desiati, P.; de Vries, K. D.; de With, M.; DeYoung, T.; Díaz-Vélez, J. C.; Dunkman, M.; Eagan, R.; Eberhardt, B.; Eisch, J.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Fedynitch, A.; Feintzeig, J.; Feusels, T.; Filimonov, K.; Finley, C.; Fischer-Wasels, T.; Flis, S.; Franckowiak, A.; Frantzen, K.; Fuchs, T.; Gaisser, T. K.; Gallagher, J.; Gerhardt, L.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Golup, G.; Gonzalez, J. G.; Goodman, J. A.; Góra, D.; Grandmont, D. T.; Grant, D.; Groß, A.; Ha, C.; Haj Ismail, A.; Hallen, P.; Hallgren, A.; Halzen, F.; Hanson, K.; Heereman, D.; Heinen, D.; Helbing, K.; Hellauer, R.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Hoffmann, R.; Homeier, A.; Hoshina, K.; Huelsnitz, W.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Ishihara, A.; Jacobi, E.; Jacobsen, J.; Jagielski, K.; Japaridze, G. S.; Jero, K.; Jlelati, O.; Kaminsky, B.; Kappes, A.; Karg, T.; Karle, A.; Kelley, J. L.; Kiryluk, J.; Kläs, J.; Klein, S. R.; Köhne, J.-H.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Kopper, C.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Krasberg, M.; Krings, K.; Kroll, G.; Kunnen, J.; Kurahashi, N.; Kuwabara, T.; Labare, M.; Landsman, H.; Larson, M. J.; Lesiak-Bzdak, M.; Leuermann, M.; Leute, J.; Lünemann, J.; Macías, O.; Madsen, J.; Maggi, G.; Maruyama, R.; Mase, K.; Matis, H. S.; McNally, F.; Meagher, K.; Merck, M.; Meures, T.; Miarecki, S.; Middell, E.; Milke, N.; Miller, J.; Mohrmann, L.; Montaruli, T.; Morse, R.; Nahnhauer, R.; Naumann, U.; Niederhausen, H.; Nowicki, S. C.; Nygren, D. R.; Obertacke, A.; Odrowski, S.; Olivas, A.; Omairat, A.; O'Murchadha, A.; Paul, L.; Pepper, J. A.; Pérez de los Heros, C.; Pfendner, C.; Pieloth, D.; Pinat, E.; Posselt, J.; Price, P. B.; Przybylski, G. T.; Rädel, L.; Rameez, M.; Rawlins, K.; Redl, P.; Reimann, R.; Resconi, E.; Rhode, W.; Ribordy, M.; Richman, M.; Riedel, B.; Rodrigues, J. P.; Rott, C.; Ruhe, T.; Ruzybayev, B.; Ryckbosch, D.; Saba, S. M.; Salameh, T.; Sander, H.-G.; Santander, M.; Sarkar, S.; Schatto, K.; Scheriau, F.; Schmidt, T.; Schmitz, M.; Schoenen, S.; Schöneberg, S.; Schönwald, A.; Schukraft, A.; Schulte, L.; Schulz, O.; Seckel, D.; Sestayo, Y.; Seunarine, S.; Shanidze, R.; Sheremata, C.; Smith, M. W. E.; Soldin, D.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stasik, A.; Stezelberger, T.; Stokstad, R. G.; Stößl, A.; Strahler, E. A.; Ström, R.; Sullivan, G. W.; Taavola, H.; Taboada, I.; Tamburro, A.; Tepe, A.; Ter-Antonyan, S.; Tešić, G.; Tilav, S.; Toale, P. A.; Toscano, S.; Unger, E.; Usner, M.; Vallecorsa, S.; van Eijndhoven, N.; Van Overloop, A.; van Santen, J.; Vehring, M.; Voge, M.; Vraeghe, M.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Weaver, Ch.; Wellons, M.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Williams, D. R.; Wissing, H.; Wolf, M.; Wood, T. R.; Woschnagg, K.; Xu, D. L.; Xu, X. W.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.; Ziemann, J.; Zierke, S.; Zoll, M.; Recht, B.; Ré, C.

    2014-02-01

    The IceCube project has transformed 1 km3 of deep natural Antarctic ice into a Cherenkov detector. Muon neutrinos are detected and their direction is inferred by mapping the light produced by the secondary muon track inside the volume instrumented with photomultipliers. Reconstructing the muon track from the observed light is challenging due to noise, light scattering in the ice medium, and the possibility of simultaneously having multiple muons inside the detector, resulting from the large flux of cosmic ray muons. This paper describes work on two problems: (1) the track reconstruction problem, in which, given a set of observations, the goal is to recover the track of a muon; and (2) the coincident event problem, which is to determine how many muons are active in the detector during a time window. Rather than solving these problems by developing more complex physical models that are applied at later stages of the analysis, our approach is to augment the detector's early reconstruction with data filters and robust statistical techniques. These can be implemented at the level of on-line reconstruction and, therefore, improve all subsequent reconstructions. Using the metric of median angular resolution, a standard metric for track reconstruction, we improve the accuracy in the initial reconstruction direction by 13%. We also present improvements in measuring the number of muons in coincident events: we can accurately determine the number of muons 98% of the time.

  3. 3D Shape-Encoded Particle Filter for Object Tracking and Its Application to Human Body Tracking

    Directory of Open Access Journals (Sweden)

    Chellappa R

    2008-01-01

    Full Text Available Abstract We present a nonlinear state estimation approach using particle filters, for tracking objects whose approximate 3D shapes are known. The unnormalized conditional density for the solution to the nonlinear filtering problem leads to the Zakai equation, and is realized by the weights of the particles. The weight of a particle represents its geometric and temporal fit, which is computed bottom-up from the raw image using a shape-encoded filter. The main contribution of the paper is the design of smoothing filters for feature extraction combined with the adoption of unnormalized conditional density weights. The "shape filter" has the overall form of the predicted 2D projection of the 3D model, while the cross-section of the filter is designed to collect the gradient responses along the shape. The 3D-model-based representation is designed to emphasize the changes in 2D object shape due to motion, while de-emphasizing the variations due to lighting and other imaging conditions. We have found that the set of sparse measurements using a relatively small number of particles is able to approximate the high-dimensional state distribution very effectively. As a measures to stabilize the tracking, the amount of random diffusion is effectively adjusted using a Kalman updating of the covariance matrix. For a complex problem of human body tracking, we have successfully employed constraints derived from joint angles and walking motion.

  4. 3D Shape-Encoded Particle Filter for Object Tracking and Its Application to Human Body Tracking

    Directory of Open Access Journals (Sweden)

    R. Chellappa

    2008-03-01

    Full Text Available We present a nonlinear state estimation approach using particle filters, for tracking objects whose approximate 3D shapes are known. The unnormalized conditional density for the solution to the nonlinear filtering problem leads to the Zakai equation, and is realized by the weights of the particles. The weight of a particle represents its geometric and temporal fit, which is computed bottom-up from the raw image using a shape-encoded filter. The main contribution of the paper is the design of smoothing filters for feature extraction combined with the adoption of unnormalized conditional density weights. The “shape filter” has the overall form of the predicted 2D projection of the 3D model, while the cross-section of the filter is designed to collect the gradient responses along the shape. The 3D-model-based representation is designed to emphasize the changes in 2D object shape due to motion, while de-emphasizing the variations due to lighting and other imaging conditions. We have found that the set of sparse measurements using a relatively small number of particles is able to approximate the high-dimensional state distribution very effectively. As a measures to stabilize the tracking, the amount of random diffusion is effectively adjusted using a Kalman updating of the covariance matrix. For a complex problem of human body tracking, we have successfully employed constraints derived from joint angles and walking motion.

  5. Particle track reconstruction in heavy materials with the Kalman technique

    International Nuclear Information System (INIS)

    The relatively recent use in HEP of the Kalman filtering and smoothing technique for the reconstruction of single tracks through gaseous detectors interspaced by heavy materials, is shown to work and to give even better results than other more classic techniques. However, fine tuning of the computer implementation has to be done carefully as well as respecting the mathematical constraints. The feasibility of the Kalman method in heavy materials here demonstrated may lead to the development of a general software package for the reconstruction of single tracks in HEP detectors. (orig.)

  6. Tracking with particle filter for high-dimensional observation and state spaces

    CERN Document Server

    Dubuisson, Séverine

    2015-01-01

    This title concerns the use of a particle filter framework to track objects defined in high-dimensional state-spaces using high-dimensional observation spaces.  Current tracking applications require us to consider complex models for objects (articulated objects, multiple objects, multiple fragments, etc.) as well as multiple kinds of information (multiple cameras, multiple modalities, etc.). This book presents some recent research that considers the main bottleneck of particle filtering frameworks (high dimensional state spaces) for tracking in such difficult conditions.

  7. Using Gaussian Process Annealing Particle Filter for 3D Human Tracking

    Directory of Open Access Journals (Sweden)

    Michael Rudzsky

    2008-01-01

    Full Text Available We present an approach for human body parts tracking in 3D with prelearned motion models using multiple cameras. Gaussian process annealing particle filter is proposed for tracking in order to reduce the dimensionality of the problem and to increase the tracker's stability and robustness. Comparing with a regular annealed particle filter-based tracker, we show that our algorithm can track better for low frame rate videos. We also show that our algorithm is capable of recovering after a temporal target loss.

  8. An alternative method for tracking a radioactive particle inside a fluid

    International Nuclear Information System (INIS)

    The proposed tracking method describes the trajectory of a radioactive particle moving in a fluid as a sequence of small cubic cells occupied by successive particle positions. In addition, the EM reconstruction algorithm was applied to get the image of the unique cell which had the greatest probability to contain the particle at a given time of a test. Next, this information was useful to calculate the coordinates and velocities of the particle at that time. The method was tested in laboratory using a gamma radiation detection system, the radioisotope 198Au and a mixer. According to the results, the maximum deviation found between theoretical and experimental values of the average rotating period was less than 8% and the particle’s reconstructed trajectories are representative of its real movement. Thus, a paradigm shift permitted us to begin the development of an alternative method to solve the complex problem of tracking the movement of a radioactive particle inside an opaque unit. - Highlights: • A practical but general method was developed to reconstruct successive positions of a radioactive particle using the EM algorithm. • This method permits to find the optimum voxel containing the particle after few iterations of the algorithm. • The proposed method can track the movement of the particle with a maximum relative error equal to 7.8%. • We can track the particle with accuracy suitable for each application varying detectors' number in the experimental setup

  9. Dim moving target tracking algorithm based on particle discriminative sparse representation

    Science.gov (United States)

    Li, Zhengzhou; Li, Jianing; Ge, Fengzeng; Shao, Wanxing; Liu, Bing; Jin, Gang

    2016-03-01

    The small dim moving target usually submerged in strong noise, and its motion observability is debased by numerous false alarms for low signal-to-noise ratio (SNR). A target tracking algorithm based on particle filter and discriminative sparse representation is proposed in this paper to cope with the uncertainty of dim moving target tracking. The weight of every particle is the crucial factor to ensuring the accuracy of dim target tracking for particle filter (PF) that can achieve excellent performance even under the situation of non-linear and non-Gaussian motion. In discriminative over-complete dictionary constructed according to image sequence, the target dictionary describes target signal and the background dictionary embeds background clutter. The difference between target particle and background particle is enhanced to a great extent, and the weight of every particle is then measured by means of the residual after reconstruction using the prescribed number of target atoms and their corresponding coefficients. The movement state of dim moving target is then estimated and finally tracked by these weighted particles. Meanwhile, the subspace of over-complete dictionary is updated online by the stochastic estimation algorithm. Some experiments are induced and the experimental results show the proposed algorithm could improve the performance of moving target tracking by enhancing the consistency between the posteriori probability distribution and the moving target state.

  10. RADON AND PROGENY ALPHA-PARTICLE ENERGY ANALYSIS USING NUCLEAR TRACK METHODOLOGY

    International Nuclear Information System (INIS)

    A preliminary procedure for alpha energy analysis of radon and progeny using Nuclear Track Methodology (NTM) is described in this paper. The method is based on the relationship between alpha-particle energies deposited in polycarbonate material (CR-39) and the track size developed after a well-established chemical etching process. Track geometry, defined by parameters such as major or minor diameters, track area and overall track length, is shown to correlate with alpha-particle energy over the range 6.00 MeV (218Po) to 7.69 MeV (214Po). Track features are measured and the data analyzed automatically using a digital imaging system and commercial PC software. Examination of particle track diameters in CR-39 exposed to environmental radon reveals a multi-modal distribution. Locations of the maxima in this distribution are highly correlated with alpha particle energies of radon daughters, and the distributions are sufficiently resolved to identify the radioisotopes. This method can be useful for estimating the radiation dose from indoor exposure to radon and its progeny.

  11. Improvement in Fast Particle Track Reconstruction with Robust Statistics

    CERN Document Server

    Aartsen, M G; Abdou, Y; Ackermann, M; Adams, J; Aguilar, J A; Ahlers, M; Altmann, D; Auffenberg, J; Bai, X; Baker, M; Barwick, S W; Baum, V; Bay, R; Beatty, J J; Bechet, S; Tjus, J Becker; Becker, K -H; Benabderrahmane, M L; BenZvi, S; Berghaus, P; Berley, D; Bernardini, E; Bernhard, A; Besson, D Z; Binder, G; Bindig, D; Bissok, M; Blaufuss, E; Blumenthal, J; Boersma, D J; Bohaichuk, S; Bohm, C; Bose, D; Böser, S; Botner, O; Brayeur, L; Bretz, H -P; Brown, A M; Bruijn, R; Brunner, J; Carson, M; Casey, J; Casier, M; Chirkin, D; Christov, A; Christy, B; Clark, K; Clevermann, F; Coenders, S; Cohen, S; Cowen, D F; Silva, A H Cruz; Danninger, M; Daughhetee, J; Davis, J C; Day, M; De Clercq, C; De Ridder, S; Desiati, P; de Vries, K D; de With, M; DeYoung, T; Díaz-Vélez, J C; Dunkman, M; Eagan, R; Eberhardt, B; Eisch, J; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Fedynitch, A; Feintzeig, J; Feusels, T; Filimonov, K; Finley, C; Fischer-Wasels, T; Flis, S; Franckowiak, A; Frantzen, K; Fuchs, T; Gaisser, T K; Gallagher, J; Gerhardt, L; Gladstone, L; Glüsenkamp, T; Goldschmidt, A; Golup, G; Gonzalez, J G; Goodman, J A; Góra, D; Grandmont, D T; Grant, D; Groß, A; Ha, C; Ismail, A Haj; Hallen, P; Hallgren, A; Halzen, F; Hanson, K; Heereman, D; Heinen, D; Helbing, K; Hellauer, R; Hickford, S; Hill, G C; Hoffman, K D; Hoffmann, R; Homeier, A; Hoshina, K; Huelsnitz, W; Hulth, P O; Hultqvist, K; Hussain, S; Ishihara, A; Jacobi, E; Jacobsen, J; Jagielski, K; Japaridze, G S; Jero, K; Jlelati, O; Kaminsky, B; Kappes, A; Karg, T; Karle, A; Kelley, J L; Kiryluk, J; Kläs, J; Klein, S R; Köhne, J -H; Kohnen, G; Kolanoski, H; Köpke, L; Kopper, C; Kopper, S; Koskinen, D J; Kowalski, M; Krasberg, M; Krings, K; Kroll, G; Kunnen, J; Kurahashi, N; Kuwabara, T; Labare, M; Landsman, H; Larson, M J; Lesiak-Bzdak, M; Leuermann, M; Leute, J; Lünemann, J; Macías, O; Madsen, J; Maggi, G; Maruyama, R; Mase, K; Matis, H S; McNally, F; Meagher, K; Merck, M; Meures, T; Miarecki, S; Middell, E; Milke, N; Miller, J; Mohrmann, L; Montaruli, T; Morse, R; Nahnhauer, R; Naumann, U; Niederhausen, H; Nowicki, S C; Nygren, D R; Obertacke, A; Odrowski, S; Olivas, A; Omairat, A; O'Murchadha, A; Paul, L; Pepper, J A; Heros, C Pérez de los; Pfendner, C; Pieloth, D; Pinat, E; Posselt, J; Price, P B; Przybylski, G T; Rädel, L; Rameez, M; Rawlins, K; Redl, P; Reimann, R; Resconi, E; Rhode, W; Ribordy, M; Richman, M; Riedel, B; Rodrigues, J P; Rott, C; Ruhe, T; Ruzybayev, B; Ryckbosch, D; Saba, S M; Salameh, T; Sander, H -G; Santander, M; Sarkar, S; Schatto, K; Scheriau, F; Schmidt, T; Schmitz, M; Schoenen, S; Schöneberg, S; Schönwald, A; Schukraft, A; Schulte, L; Schulz, O; Seckel, D; Sestayo, Y; Seunarine, S; Shanidze, R; Sheremata, C; Smith, M W E; Soldin, D; Spiczak, G M; Spiering, C; Stamatikos, M; Stanev, T; Stanisha, N A; Stasik, A; Stezelberger, T; Stokstad, R G; Stößl, A; Strahler, E A; Ström, R; Sullivan, G W; Taavola, H; Taboada, I; Tamburro, A; Tepe, A; Ter-Antonyan, S; Tešić, G; Tilav, S; Toale, P A; Toscano, S; Unger, E; Usner, M; Vallecorsa, S; van Eijndhoven, N; Van Overloop, A; van Santen, J; Vehring, M; Voge, M; Vraeghe, M; Walck, C; Waldenmaier, T; Wallraff, M; Weaver, Ch; Wellons, M; Wendt, C; Westerhoff, S; Whitehorn, N; Wiebe, K; Wiebusch, C H; Williams, D R; Wissing, H; Wolf, M; Wood, T R; Woschnagg, K; Xu, D L; Xu, X W; Yanez, J P; Yodh, G; Yoshida, S; Zarzhitsky, P; Ziemann, J; Zierke, S; Zoll, M

    2013-01-01

    The IceCube project has transformed one cubic kilometer of deep natural Antarctic ice into a Cherenkov detector. Muon neutrinos are detected and their direction inferred by mapping the light produced by the secondary muon track inside the volume instrumented with photomultipliers. Reconstructing the muon track from the observed light is challenging due to noise, light scattering in the ice medium, and the possibility of simultaneously having multiple muons inside the detector, resulting from the large flux of cosmic ray muons. This manuscript describes work on two problems: (1) the track reconstruction problem, in which, given a set of observations, the goal is to recover the track of a muon; and (2) the coincident event problem, which is to determine how many muons are active in the detector during a time window. Rather than solving these problems by developing more complex physical models that are applied at later stages of the analysis, our approach is to augment the detectors early reconstruction with dat...

  12. Nuclear track detectors for charged particles and neutrons

    International Nuclear Information System (INIS)

    It was with great emotion that I accepted to be a guest speaker to this memorial section dedicated to my old-time friend, Prof. Radomir Ilic. In addition to being one of the most outstanding scientists in the field of nuclear tracks, Prof. Radomir Ilic has been always highly acclaimed by the scientific community for his enthusiasm, his warm friendship, and his great vitality. Through his successful editorial activities, Prof. Ilic has proved to be very able to address the field of nuclear tracks to very wide audiences with special regards to young students. It was here in Portoroz, that Prof. Radomir Ilic was our host as the organiser of the 21st International Conference on Nuclear Tracks in Solids. All the participants have great memories of this very successful international conference. For all these reasons, the 2006 edition of the International Conference on Nuclear Energy for new Europe, with its wide audience and its venue at Portoroz, can be considered as one of the most appropriate forum for the memorial lecture of Prof. Radomir Ilic. The present paper will be dealing with the solid state nuclear track detectors-SSNTDs and their successful applications for the measurements of cosmic-ray-neutrons and terrestrial radioactivity, namely radon. (author)

  13. Aerogel Track Morphology: Measurement, Three Dimensional Reconstruction and Particle Location using Confocal Laser Scanning Microscopy

    Science.gov (United States)

    Kearsley, A. T.; Ball, A. D.; Wozniakiewicz, P. A.; Graham, G. A.; Burchell, M. J.; Cole, M. J.; Horz, F.; See, T. H.

    2007-01-01

    The Stardust spacecraft returned the first undoubted samples of cometary dust, with many grains embedded in the silica aerogel collector . Although many tracks contain one or more large terminal particles of a wide range of mineral compositions , there is also abundant material along the track walls. To help interpret the full particle size, structure and mass, both experimental simulation of impact by shots and numerical modeling of the impact process have been attempted. However, all approaches require accurate and precise measurement of impact track size parameters such as length, width and volume of specific portions. To make such measurements is not easy, especially if extensive aerogel fracturing and discoloration has occurred. In this paper we describe the application and limitations of laser confocal imagery for determination of aerogel track parameters, and for the location of particle remains.

  14. Fast Visual Object Tracking Using Modified kalman and Particle Filtering Algorithms in the Presence of Occlusions

    Directory of Open Access Journals (Sweden)

    G.Mallikarjuna Rao

    2014-09-01

    Full Text Available In the present day real time applications of visual object tracking in surveillance, it has become extremely complex, time consuming and tricky to do the tracking when there are occlusions are present for small duration or for longer time and also when it is done in outdoor environments. In these conditions, the target to be tracked can be lost for few seconds and that should be tracked as soon as possible. As from the literature it is observed that particle filter can be able to track the target robustly in different kinds of background conditions, and it’s robust to partial occlusion. However, this tracking cannot recover from large proportion of occlusion and complete occlusion, to avoid this condition, we proposed two new algorithms (modified kalman and modified particle filter for fast tracking of objects in the presence of occlusions. We considered the complete occlusion of tracking object and the main objective is how fast the system is able to track the object after the occlusion is crossed. From the experimental results, it is observed that the proposed algorithms have shown good improvement in results compared to the traditional methods.

  15. A particle-tracking code (TRACK3D) for convective solute transport modelling in the geosphere: Description and user's manual

    International Nuclear Information System (INIS)

    A deterministic particle-tracking code (TRACK3D) has been developed to compute convective flow paths of conservative (nonreactive) contaminants through porous geological media. TRACK3D requires the groundwater velocity distribution, which, in our applications, results from flow simulations using AECL's MOTIF code. The MOTIF finite-element code solves the transient and steady-state coupled equations of groundwater flow, solute transport and heat transport in fractured/porous media. With few modifications, TRACK3D can be used to analyse the velocity distributions calculated by other finite-element or finite-difference flow codes. TRACK3D temporarily integrates the velocity distribution, in conjunction with the model geometry, to calculate convective flow paths, exit locations and travel times of as many as 1000 water-coincident particles released in the flow domain. Both steady-state and time-varying velocity distributions can be handled. TRACK3D requires the flow domain to be discretized by a finite-element mesh containing as many as 25 000 elements. The mesh can contain three-dimensional (3-D) eight-noded hexahedral elements representing a solid region, or two-dimensional four-noded quadrilateral elements representing a plane, which can be oriented arbitrarily in 3-D space. TRACK3D has been verified by comparison with analytical and numerical solutions, and in an independent confirmation by Ontario Hydro Research. This report describes the assumptions, limitations, organization, operation and applications of the TRACK3D code, and provides a comprehensive user's manual. TRACK3D has been applied by AECL Research in the concept assessment phase of the Canadian Nuclear Fuel Waste Management Program to analyse convective radionuclide pathways and travel times from a hypothetical vault containing (for example) CANDU reactor fuel waste, through the surrounding geologic formations to discharge locations in the biosphere. The program has been used to examine the sensitivity

  16. Tracking Particles in Flows near Invariant Manifolds via Balance Functions

    CERN Document Server

    Kuehn, Christian; Kuhlmann, Hendrik C

    2016-01-01

    Particles moving inside a fluid near, and interacting with, invariant manifolds is a common phenomenon in a wide variety of applications. One elementary question is whether we can determine once a particle has entered a neighbourhood of an invariant manifold, when it leaves again. Here we approach this problem mathematically by introducing balance functions, which relate the entry and exit points of a particle by an integral variational formula. We define, study, and compare different natural choices for balance functions and conclude that an efficient compromise is to employ normal infinitesimal Lyapunov exponents. We apply our results to two different model flows: a regularized solid-body rotational flow and the asymmetric Kuhlmann--Muldoon model developed in the context of liquid bridges. Furthermore, we employ full numerical simulations of the Navier-Stokes equations of a two-way coupled particle in a shear--stress-driven cavity to test balance functions for a particle moving near an invariant wall. In co...

  17. Particle-tracking calculation of classical transport in high-beta field-reversed configuration plasma

    International Nuclear Information System (INIS)

    In this paper, classical particle transport processes in field-reversed configuration plasma is investigated by particle-tracking calculations. The end-loss rate is found to increase with ion temperature, and the temperature dependence is much stronger than that of the Bohm scaling and the empirical scaling. (author)

  18. Visible light photon counters (VLPCs) for high rate tracking medical imaging and particle astrophysics

    International Nuclear Information System (INIS)

    This paper is on the operation principles of the Visible Light Photon Counters (VLPCs), application to high luminosity-high multiplicity tracking for High Energy Charged Particle Physics, and application to Medical Imaging and Particle Astrophysics. The VLPCs as Solid State Photomultipliers (SSPMS) with high quantum efficiency can detect down to single photons very efficiently with excellent time resolution and high avalanche gains

  19. Visible light photon counters (VLPCs) for high rate tracking medical imaging and particle astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Atac, M.

    1998-02-01

    This paper is on the operation principles of the Visible Light Photon Counters (VLPCs), application to high luminosity-high multiplicity tracking for High Energy Charged Particle Physics, and application to Medical Imaging and Particle Astrophysics. The VLPCs as Solid State Photomultipliers (SSPMS) with high quantum efficiency can detect down to single photons very efficiently with excellent time resolution and high avalanche gains.

  20. Lagrangian particle tracking in three dimensions via single-camera in-line digital holography

    Energy Technology Data Exchange (ETDEWEB)

    Lu Jiang; Fugal, Jacob P; Nordsiek, Hansen; Saw, Ewe Wei; Shaw, Raymond A; Yang Weidong [Department of Physics, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA International Collaboration for Turbulence Research (United States)], E-mail: rashaw@mtu.edu

    2008-12-15

    Lagrangian particle trajectories are measured in three spatial dimensions with a single camera using the method of digital in-line holography. Lagrangian trajectories of 60-120 {mu}m diameter droplets in turbulent air obtained with data from one camera compare favorably with tracks obtained from a simultaneous dual-camera data set, the latter having high spatial resolution in all three dimensions. Using the single-camera system, particle motion along the optical axis is successfully tracked, allowing for long, continuous 3D tracks, but the depth resolution based on standard reconstruction methods is not sufficient to obtain accurate acceleration measurements for that component. Lagrangian velocity distributions for all three spatial components agree within reasonable sampling uncertainties and Lagrangian acceleration distributions agree for the two lateral components. An equivalent single-camera, imaging-based 2D tracking system would be challenged by the particle densities tested, but the holographic configuration allows for 3D tracking in the dilute limit. The method also allows particle size, shape and orientation to be measured along the trajectory. Lagrangian measurements of particle size provide a direct measure of particle size uncertainty under realistic conditions sampled from the entire measurement volume.

  1. Comparison of particle tracks calculated by Monte Carlo computer codes with experimental tracks observed with the Harwell low pressure cloud chamber

    International Nuclear Information System (INIS)

    Photographs of the droplets associated with the ionisations caused by charged particle tracks in the Harwell low pressure cloud chamber have been analysed. The radiation types these represent are alpha particles, protons and low energy X rays (carbon and aluminium) in either a tissue-equivalent gas or water vapour. The tracks were used to test the validity of two Monte Carlo codes developed by Wilson and Paratzke, namely MOCA14 for the generation of proton and alpha particle tracks, and MOCA8 for the generation of electron tracks. The comparisons showed that the code MOCA14 would appear to be valid for protons with energies greater than about 390 keV, and for alpha particles with energies greater than 1.6 MeV. No disagreement was found between the low energy X ray tracks from the cloud chamber and the tracks calculated from MOCA8, although this comparison was severely limited by droplet diffusion. (author)

  2. Cardiac fiber tracking using adaptive particle filtering based on tensor rotation invariant in MRI

    Science.gov (United States)

    Kong, Fanhui; Liu, Wanyu; Magnin, Isabelle E.; Zhu, Yuemin

    2016-03-01

    Diffusion magnetic resonance imaging (dMRI) is a non-invasive method currently available for cardiac fiber tracking. However, accurate and efficient cardiac fiber tracking is still a challenge. This paper presents a probabilistic cardiac fiber tracking method based on particle filtering. In this framework, an adaptive sampling technique is presented to describe the posterior distribution of fiber orientations by adjusting the number and status of particles according to the fractional anisotropy of diffusion. An observation model is then proposed to update the weight of particles by rotating diffusion tensor from the primary eigenvector to a given fiber orientation while keeping the shape of the tensor invariant. The results on human cardiac dMRI show that the proposed method is robust to noise and outperforms conventional streamline and particle filtering techniques.

  3. Charged Particle Tracking for the GlueX Detector

    Science.gov (United States)

    Taylor, Simon; GlueX Collaboration

    2011-04-01

    The GlueX experiment is a new experiment under construction at the Thomas Jefferson National Accelerator Facility designed to study gluonic degrees of freedom via the production of ``hybrid'' mesons with exotic quantum numbers. At full luminosity, the trigger rate is expected to be on the order of 150 kHz and the data rate to tape is expected to be on the order of 300 MB/s. In order to reduce the reconstruction time, the current GlueX analysis framework is multi-threaded such that multiple events can be analyzed in parallel on multi-core machines. The tracking code presents the largest bottleneck in the event reconstruction. By taking advantage of Single-Instruction, Multiple-Data (SIMD) instructions in the three-vector and matrix operations needed in the tracking code, the reconstruction can be sped up considerably. The current status of the tracking reconstruction for GlueX will be presented. This work was supported by the US Department of Energy contract DE-AC05-06OR23177, under which Jefferson Science Associates, LLC operates Thomas Jefferson National Accelerator Facility.

  4. Path sampling for particle filters with application to multi-target tracking

    CERN Document Server

    Maroulas, Vasileios

    2010-01-01

    In recent work (arXiv:1006.3100v1), we have presented a novel approach for improving particle filters for multi-target tracking. The suggested approach was based on Girsanov's change of measure theorem for stochastic differential equations. Girsanov's theorem was used to design a Markov Chain Monte Carlo step which is appended to the particle filter and aims to bring the particle filter samples closer to the observations. In the current work, we present an alternative way to append a Markov Chain Monte Carlo step to a particle filter to bring the particle filter samples closer to the observations. Both current and previous approaches stem from the general formulation of the filtering problem. We have used the currently proposed approach on the problem of multi-target tracking for both linear and nonlinear observation models. The numerical results show that the suggested approach can improve significantly the performance of a particle filter.

  5. Radon and progeny alpha-particle energy analysis using nuclear track methodology

    International Nuclear Information System (INIS)

    A preliminary procedure for alpha-energy analysis of radon and its progeny using nuclear track methodology (NTM) is described in this paper. The method is based on the relationship between alpha-particle energies deposited in polycarbonate material (CR-39) and the track size developed after a well-established chemical etching process. Track geometry, defined by parameters such as major or minor diameters, track area and overall track length, is shown to correlate with alpha-particle energy over the range 6.00 MeV (218Po) to 7.69 MeV (214Po). Track features are measured and the data analyzed automatically using a digital imaging system and commercial PC software. Examination of particle track diameters in CR-39 exposed to environmental radon reveals a multi-modal distribution. Locations of the maxima in this distribution are highly correlated with alphaparticle energies of radon daughters, and the distributions are sufficiently resolved to identify the radioisotopes. This method can be useful for estimating the radiation dose from indoor exposure to radon and its progeny. (author)

  6. Improved estimation of anomalous diffusion exponents in single particle tracking experiments

    OpenAIRE

    Bronshtein, Eldad Kepten Irena; Garini, Yuval

    2012-01-01

    The Mean Square Displacement is a central tool in the analysis of Single Particle Tracking experiments, shedding light on various biophysical phenomena. Frequently, parameters are extracted by performing time-averages on single particle trajectories followed by ensemble averaging. This procedure however, suffers from two systematic errors when applied to particles that perform anomalous diffusion. The first is significant at short time lags and is induced by measurement errors. The second ari...

  7. Stereoscopic particle tracking for 3D touch, vision and closed-loop control in optical tweezers

    International Nuclear Information System (INIS)

    Force measurement in an interactive 3D micromanipulation system can allow the user to make delicate adjustments, and to explore surfaces with touch as well as vision. We present a system to achieve this on the micron scale using stereoscopic particle tracking combined with holographic optical tweezers, which can track particles with nanometre accuracy. 2D tracking of particles in each of the stereo images gives 3D positions for each particle. This takes less than 200 µs per image pair, using a 1D 'symmetry transform' applied to each row and column of a 2D image, which can maintain tracking of particles throughout the 10 µm axial range. The only parameters required are the geometry of the imaging system, and therefore there is no need to recalibrate for different particle sizes or refractive indices. Consequently, we can calculate the force exerted by the optical trap in real time at 1 kilohertz, allowing us to implement a force-feedback interface (with a loop rate of 400 Hz). In combination with our OpenGL hologram calculation engine, the system has a closed-loop bandwidth of 20 Hz. This allows us to stabilize trapped particles axially through active feedback, cancelling out some Brownian motion. For the weak traps we use here (spring constant k≈2 pN µm−1), this results in a threefold increase in axial stiffness. We demonstrate the 3D interface by probing an oil droplet, mapping out its surface in the y–z plane

  8. Orbital single particle tracking on a commercial confocal microscope using piezoelectric stage feedback

    International Nuclear Information System (INIS)

    Single Particle Tracking (SPT) is a technique used to locate fluorescent particles with nanometer precision. In the orbital tracking method the position of a particle is obtained analyzing the distribution of intensity along a circular orbit scanned around the particle. In combination with an active feedback this method allows tracking of particles in 2D and 3D with millisecond temporal resolution. Here we describe a SPT setup based on a feedback approach implemented with minimal modification of a commercially available confocal laser scanning microscope, the Zeiss LSM 510, in combination with an external piezoelectric stage scanner. The commercial microscope offers the advantage of a user-friendly software interface and pre-calibrated hardware components. The use of an external piezo-scanner allows the addition of feedback into the system but also represents a limitation in terms of its mechanical response. We describe in detail this implementation of the orbital tracking method and discuss advantages and limitations. As an example of application to live cell experiments we perform the 3D tracking of acidic vesicles in live polarized epithelial cells. (paper)

  9. Local characterization of hindered Brownian motion by using digital video microscopy and 3D particle tracking

    International Nuclear Information System (INIS)

    In this article we present methods for measuring hindered Brownian motion in the confinement of complex 3D geometries using digital video microscopy. Here we discuss essential features of automated 3D particle tracking as well as diffusion data analysis. By introducing local mean squared displacement-vs-time curves, we are able to simultaneously measure the spatial dependence of diffusion coefficients, tracking accuracies and drift velocities. Such local measurements allow a more detailed and appropriate description of strongly heterogeneous systems as opposed to global measurements. Finite size effects of the tracking region on measuring mean squared displacements are also discussed. The use of these methods was crucial for the measurement of the diffusive behavior of spherical polystyrene particles (505 nm diameter) in a microfluidic chip. The particles explored an array of parallel channels with different cross sections as well as the bulk reservoirs. For this experiment we present the measurement of local tracking accuracies in all three axial directions as well as the diffusivity parallel to the channel axis while we observed no significant flow but purely Brownian motion. Finally, the presented algorithm is suitable also for tracking of fluorescently labeled particles and particles driven by an external force, e.g., electrokinetic or dielectrophoretic forces

  10. VOLTAGE REGULATORS ASYNCHRONOUS GENERATORS

    Directory of Open Access Journals (Sweden)

    Grigorash O. V.

    2015-06-01

    Full Text Available A promising is currently the use of asynchronous generators with capacitive excitation as a source of electricity in stand-alone power systems. Drive asynchronous generators may exercise as a thermal engine and wind wheel wind power plant or turbines of small hydropower plants. The article discusses the structural and schematics of voltage stabilizers and frequency of asynchronous generators with improved operational and technical specifications. Technical novelty of design solutions of the magnetic system and stabilizers asynchronous generator of electricity parameters confirmed by the patents for the invention of the Russian Federation. The proposed technical solution voltage stabilizer asynchronous generators, can reduce the weight of the block capacitors excitation and reactive power compensation, as well as to simplify the control system power circuit which has less power electronic devices. For wind power plants it is an important issue not only to stabilize the voltage of the generator, but also the frequency of the current. Recommend functionality stabilizer schemes parameters of electric power made for direct frequency converters with artificial and natural switching power electronic devices. It is also proposed as part of stabilization systems use single-phase voltage, three-phase transformers with rotating magnetic field, reduce the level of electromagnetic interference generated by power electronic devices for switching, enhance the efficiency and reliability of the stabilizer.

  11. Autonomous sensor particle for parameter tracking in large vessels

    International Nuclear Information System (INIS)

    A self-powered and neutrally buoyant sensor particle has been developed for the long-term measurement of spatially distributed process parameters in the chemically harsh environments of large vessels. One intended application is the measurement of flow parameters in stirred fermentation biogas reactors. The prototype sensor particle is a robust and neutrally buoyant capsule, which allows free movement with the flow. It contains measurement devices that log the temperature, absolute pressure (immersion depth) and 3D-acceleration data. A careful calibration including an uncertainty analysis has been performed. Furthermore, autonomous operation of the developed prototype was successfully proven in a flow experiment in a stirred reactor model. It showed that the sensor particle is feasible for future application in fermentation reactors and other industrial processes

  12. A drift chamber combined with a GEM stage for particle-identification and tracking studies

    International Nuclear Information System (INIS)

    Gaseous tracking detectors play a key role in existing and planned hadron and particle physics experiments. A universal tracking device has been set up for optimizing the performance of existing trackers (ANKE rate at COSY, WASA rate at COSY) and for developing new concepts (PANDA rate at FAIR). The setup consists of a drift gap followed by a GEM amplification stage and a stack of drift chambers. Additional scintillators above and below the setup give time reference signals for cosmics measurements. Data are read out with 160 MHz flash ADCs and with F1-TDCs. The setup is described. Results on tracking resolution, cluster formation along cosmics tracks, gas amplification for various mixtures are presented. The implication for particle identification based on the energy loss for e.g. straw detectors is discussed.

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

    International Nuclear Information System (INIS)

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

  14. A framework to integrate particle filters for robust tracking in non-stationary environments

    OpenAIRE

    Moreno Noguer, Francesc; Sanfeliu Cortés, Alberto

    2005-01-01

    In this paper we propose a new framework to integrate several particle filters, in order to obtain a robust tracking system able to cope with abrupt changes of illumination and position of the target. The proposed method is analytically justified and allows to build a tracking procedure that adapts online and simultaneously the colorspace where the image points are represented, the color distributions of the object and background and the contour of the object.

  15. Visual object tracking in 3D with color based particle filter

    OpenAIRE

    Barrera González, Pablo; Matellán Olivera, Vicente; Cañas, José María

    2005-01-01

    This paper addresses the problem of determining the current 3D location of a moving object and robustly tracking it from a sequence of camera images. The approach presented here uses a particle lter and does not perform any explicit triangulation. Only the color of the object to be tracked is required, but not any precise motion model. The observation model we have developed avoids the color ltering of the entire image. That and the MonteCarlo techniques inside the part...

  16. Markerless Human Motion Tracking Using Hierarchical Multi-Swarm Cooperative Particle Swarm Optimization

    OpenAIRE

    Saini, Sanjay; Zakaria, Nordin; Rambli, Dayang Rohaya Awang; Sulaiman, Suziah

    2015-01-01

    The high-dimensional search space involved in markerless full-body articulated human motion tracking from multiple-views video sequences has led to a number of solutions based on metaheuristics, the most recent form of which is Particle Swarm Optimization (PSO). However, the classical PSO suffers from premature convergence and it is trapped easily into local optima, significantly affecting the tracking accuracy. To overcome these drawbacks, we have developed a method for the problem based on ...

  17. Particle tracking during Ostwald ripening using time-resolved laboratory X-ray microtomography

    Energy Technology Data Exchange (ETDEWEB)

    Werz, T., E-mail: thomas.werz@uni-ulm.de [Ulm University, Institute of Micro and Nanomaterials, Albert-Einstein-Allee 47, 89081 (Germany); Baumann, M. [Ulm University, Institute of Micro and Nanomaterials, Albert-Einstein-Allee 47, 89081 (Germany); Wolfram, U. [Ulm University, Institute of Orthopaedic Research and Biomechanics, Helmholtzstrasse 14, 89081 (Germany); Krill, C.E. [Ulm University, Institute of Micro and Nanomaterials, Albert-Einstein-Allee 47, 89081 (Germany)

    2014-04-01

    Laboratory X-ray microtomography is investigated as a method for obtaining time-resolved images of microstructural coarsening of the semisolid state of Al–5 wt.% Cu samples during Ostwald ripening. Owing to the 3D imaging capability of tomography, this technique uniquely provides access to the growth rates of individual particles, thereby not only allowing a statistical characterization of coarsening—as has long been possible by conventional metallography—but also enabling quantification of the influence of local environment on particle boundary migration. The latter information is crucial to understanding growth kinetics during Ostwald ripening at high volume fractions of the coarsening phase. Automated image processing and segmentation routines were developed to close gaps in the network of particle boundaries and to track individual particles from one annealing step to the next. The particle tracking success rate places an upper bound of only a few percent on the likelihood of segmentation errors for any given particle. The accuracy of particle size trajectories extracted from the time-resolved tomographic reconstructions is correspondingly high. Statistically averaged coarsening data and individual particle growth rates are in excellent agreement with the results of prior experimental studies and with computer simulations of Ostwald ripening. - Highlights: • Ostwald ripening in Al–5 wt.% Cu measured by laboratory X-ray microtomography • Time-resolved measurement of individual particle growth • Automated segmentation routines developed to close gaps in particle boundary network • Particle growth/shrinkage rates deviate from LSW model prediction.

  18. Particle tracking during Ostwald ripening using time-resolved laboratory X-ray microtomography

    International Nuclear Information System (INIS)

    Laboratory X-ray microtomography is investigated as a method for obtaining time-resolved images of microstructural coarsening of the semisolid state of Al–5 wt.% Cu samples during Ostwald ripening. Owing to the 3D imaging capability of tomography, this technique uniquely provides access to the growth rates of individual particles, thereby not only allowing a statistical characterization of coarsening—as has long been possible by conventional metallography—but also enabling quantification of the influence of local environment on particle boundary migration. The latter information is crucial to understanding growth kinetics during Ostwald ripening at high volume fractions of the coarsening phase. Automated image processing and segmentation routines were developed to close gaps in the network of particle boundaries and to track individual particles from one annealing step to the next. The particle tracking success rate places an upper bound of only a few percent on the likelihood of segmentation errors for any given particle. The accuracy of particle size trajectories extracted from the time-resolved tomographic reconstructions is correspondingly high. Statistically averaged coarsening data and individual particle growth rates are in excellent agreement with the results of prior experimental studies and with computer simulations of Ostwald ripening. - Highlights: • Ostwald ripening in Al–5 wt.% Cu measured by laboratory X-ray microtomography • Time-resolved measurement of individual particle growth • Automated segmentation routines developed to close gaps in particle boundary network • Particle growth/shrinkage rates deviate from LSW model prediction

  19. A study of thermal counterflow using particle tracking velocimetry

    Czech Academy of Sciences Publication Activity Database

    Chagovets, Tymofiy; Van Sciver, S.W.

    2011-01-01

    Roč. 23, č. 10 (2011), 107101/1-107101/5. ISSN 1070-6631 Institutional research plan: CEZ:AV0Z10100520 Keywords : tracer particles * PTV * superfluid helium Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.926, year: 2011

  20. Analytical Benchmarking, Precision Particle Tracking, Electric and Magnetic Storage Rings, Runge-Kutta, Predictor-Corrector

    CERN Document Server

    Metodiev, E M; Fandaros, M; Haciomeroglu, S; Huang, D; Huang, K L; Patil, A; Prodromou, R; Semertzidis, O A; Sharma, D; Stamatakis, A N; Orlov, Y F; Semertzidis, Y K

    2015-01-01

    A set of analytical benchmarks for tracking programs are required for precision storage ring experiments. To determine the accuracy of precision tracking programs in electric and magnetic rings, a variety of analytical estimates of particle and spin dynamics in the rings are developed and compared to the numerical results of tracking simulations. Initial discrepancies in the comparisons indicated the need for improvement of several of the analytical estimates. As an example, we find that the fourth order Runge-Kutta/Predictor-Corrector method was accurate but slow, and that it passed all the benchmarks it was tested against, often to the sub-part per billion level. Thus high precision analytical estimates and tracking programs based on fourth order Runge-Kutta/Predictor-Corrector integration can be used to benchmark faster tracking programs for accuracy.

  1. Track structure of proton and α particle in water and DNA damage spectrum

    International Nuclear Information System (INIS)

    The Monte Carlo track structure model MOCA15 of the proton and α particle in water has been extended. In the simulation, the energy range of proton and α particle is 0.3-5 MeV/u. The cutoff energy of secondary energy electron is 1 eV. Tracks were analyzed to provide confirmation on the reliability of the code and the information on physical parameters, such as range, radial dose profiles. Model calculation shows the good agreement with the experimental data. A simple fast algorithm to simulate DNA damages spectrum produced by ionizing radiation was used. This algorithm captures the major trends in the DNA damage spectrum predicted using detailed track-structure simulations. This method is fast and can be generalized easily. The parameters used in the damage simulation algorithm are provided for proton and alpha particle. This work is systematic. (author)

  2. Drop deposition in annular two-phase flow calculated with Lagrangian Particle Tracking

    International Nuclear Information System (INIS)

    Highlights: • A new drop size correlation is proposed. • Increased drop size accounts for increased concentration. • LPT model has capability to predict obstacle effect. - Abstract: Lagrangian Particle Tracking is tested for its capability to predict deposition rates in pipes and pipes with obstacle. The drop size is one of the input parameters, which defines in its major part the deposition process. A new correlation is proposed to estimate the drop size, following a systematic analysis of the experimental drop sizes in annular two-phase flow. The Lagrangian Particle Tracking model showed good capability of prediction in the cases where the drop size is known; however, when the drop size is estimated the inaccuracy in calculated deposition rate is high. If the drop size is known at the inlet of the channel, Lagrangian Particle Tracking shows good capability of predicting the deposition increase downstream of the obstacle for steam-water flows of 5, 10 and 15 bar pressure

  3. Particle track analysis of natural decay series nuclides in sediments and pore waters

    International Nuclear Information System (INIS)

    Solid-state nuclear track detectors sensitive to alpha or fission product particles have been used, with some success, to measure low activities of natural decay series nuclides in environmental samples. Applications assessed thus far include excess 230Th and 210Pb dating of sediments, determination of uranium in sediment matrices and pore waters and dissolved 222Rn assay of aqueous solutions. Whenever possible, data obtained by the particle track methods have been compared with the results of conventional radiochemical analyses on duplicate samples. The observed agreement, although illustrating some limitations of particle track techniques, suggests that they have considerable potential in environmental radiochemistry. Not only are the techniques less skilled, less expensive and more portable than coventional methodology, but also they are generally non-destructive, require much less sample, register very low background levels and are, in some cases, more sensitive. (author)

  4. Analytical benchmarks for precision particle tracking in electric and magnetic rings

    International Nuclear Information System (INIS)

    To determine the accuracy of tracking programs for precision storage ring experiments, analytical estimates of particle and spin dynamics in electric and magnetic rings were developed and compared to the numerical results of a tracking program based on Runge–Kutta/Predictor–Corrector integration. Initial discrepancies in the comparisons indicated the need to improve several of the analytical estimates. In the end, this rather slow program passed all benchmarks, often agreeing with the analytical estimates to the part-per-billion level. Thus, it can in turn be used to benchmark faster tracking programs for accuracy

  5. Analytical benchmarks for precision particle tracking in electric and magnetic rings

    Energy Technology Data Exchange (ETDEWEB)

    Metodiev, E.M. [Brookhaven National Laboratory, Physics Department, Upton, NY 11973 (United States); Harvard College, Harvard University, Cambridge, MA 02138 (United States); Center for Axion and Precision Physics Research, IBS, Daejeon 305-701 (Korea, Republic of); Department of Physics, KAIST, Daejeon 305-701 (Korea, Republic of); D' Silva, I.M.; Fandaros, M. [Brookhaven National Laboratory, Physics Department, Upton, NY 11973 (United States); Gaisser, M. [Center for Axion and Precision Physics Research, IBS, Daejeon 305-701 (Korea, Republic of); Department of Physics, KAIST, Daejeon 305-701 (Korea, Republic of); Hacıömeroğlu, S. [Brookhaven National Laboratory, Physics Department, Upton, NY 11973 (United States); Center for Axion and Precision Physics Research, IBS, Daejeon 305-701 (Korea, Republic of); Istanbul Technical University, Istanbul 34469 (Turkey); Department of Physics, KAIST, Daejeon 305-701 (Korea, Republic of); Huang, D. [Brookhaven National Laboratory, Physics Department, Upton, NY 11973 (United States); Huang, K.L. [Brookhaven National Laboratory, Physics Department, Upton, NY 11973 (United States); Harvard College, Harvard University, Cambridge, MA 02138 (United States); Patil, A.; Prodromou, R.; Semertzidis, O.A.; Sharma, D.; Stamatakis, A.N. [Brookhaven National Laboratory, Physics Department, Upton, NY 11973 (United States); Orlov, Y.F. [Department of Physics, Cornell University, Ithaca, NY (United States); Semertzidis, Y.K. [Brookhaven National Laboratory, Physics Department, Upton, NY 11973 (United States); Center for Axion and Precision Physics Research, IBS, Daejeon 305-701 (Korea, Republic of); Department of Physics, KAIST, Daejeon 305-701 (Korea, Republic of)

    2015-10-11

    To determine the accuracy of tracking programs for precision storage ring experiments, analytical estimates of particle and spin dynamics in electric and magnetic rings were developed and compared to the numerical results of a tracking program based on Runge–Kutta/Predictor–Corrector integration. Initial discrepancies in the comparisons indicated the need to improve several of the analytical estimates. In the end, this rather slow program passed all benchmarks, often agreeing with the analytical estimates to the part-per-billion level. Thus, it can in turn be used to benchmark faster tracking programs for accuracy.

  6. Video object tracking using improved chamfer matching and condensation particle filter

    Science.gov (United States)

    Wu, Tao; Ding, Xiaoqing; Wang, Shengjin; Wang, Kongqiao

    2008-02-01

    Object tracking is an essential problem in the field of video and image processing. Although tracking algorithms working on gray video are convenient in actual applications, they are more difficult to be developed than those using color features, since less information is taken into account. Few researches have been dedicated to tracking object using edge information. In this paper, we proposed a novel video tracking algorithm based on edge information for gray videos. This method adopts the combination of a condensation particle filter and an improved chamfer matching. The improved chamfer matching is rotation invariant and capable of estimating the shift between an observed image patch and a template by an orientation distance transform. A modified discriminative likelihood measurement method that focuses on the difference is adopted. These values are normalized and used as the weights of particles which predict and track the object. Experiment results show that our modifications to chamfer matching improve its performance in video tracking problem. And the algorithm is stable, robust, and can effectively handle rotation distortion. Further work can be done on updating the template to adapt to significant viewpoint and scale changes of the appearance of the object during the tracking process.

  7. Asynchronized synchronous machines

    CERN Document Server

    Botvinnik, M M

    1964-01-01

    Asynchronized Synchronous Machines focuses on the theoretical research on asynchronized synchronous (AS) machines, which are "hybrids” of synchronous and induction machines that can operate with slip. Topics covered in this book include the initial equations; vector diagram of an AS machine; regulation in cases of deviation from the law of full compensation; parameters of the excitation system; and schematic diagram of an excitation regulator. The possible applications of AS machines and its calculations in certain cases are also discussed. This publication is beneficial for students and indiv

  8. Asynchronous Variational Contact Mechanics

    CERN Document Server

    Vouga, Etienne; Tamstorf, Rasmus; Grinspun, Eitan

    2010-01-01

    An asynchronous, variational method for simulating elastica in complex contact and impact scenarios is developed. Asynchronous Variational Integrators (AVIs) are extended to handle contact forces by associating different time steps to forces instead of to spatial elements. By discretizing a barrier potential by an infinite sum of nested quadratic potentials, these extended AVIs are used to resolve contact while obeying momentum- and energy-conservation laws. A series of two- and three-dimensional examples illustrate the robustness and good energy behavior of the method.

  9. A Parallel Implementation of Particle Tracking with Space Charge Effects on an Intel iPSC/860

    OpenAIRE

    Chang, L.; Bourianoff, G.; B. Cole; S. Machida

    1993-01-01

    Particle-tracking simulation is one of the scientific applications that is well suited to parallel computations. At the Superconducting Super Collider, it has been theoretically and empirically demonstrated that particle tracking on a designed lattice can achieve very high parallel efficiency on a MIMD Intel iPSC/860 machine. The key to such success is the realization that the particles can be tracked independently without considering their interaction. The perfectly parallel nature of partic...

  10. Charged particle tracking at Titan, and further applications

    Science.gov (United States)

    Bebesi, Zsofia; Erdos, Geza; Szego, Karoly

    2016-04-01

    We use the CAPS ion data of Cassini to investigate the dynamics and origin of Titan's atmospheric ions. We developed a 4th order Runge-Kutta method to calculate particle trajectories in a time reversed scenario. The test particle magnetic field environment imitates the curved magnetic environment in the vicinity of Titan. The minimum variance directions along the S/C trajectory have been calculated for all available Titan flybys, and we assumed a homogeneous field that is perpendicular to the minimum variance direction. Using this method the magnetic field lines have been calculated along the flyby orbits so we could select those observational intervals when Cassini and the upper atmosphere of Titan were magnetically connected. We have also taken the Kronian magnetodisc into consideration, and used different upstream magnetic field approximations depending on whether Titan was located inside of the magnetodisc current sheet, or in the lobe regions. We also discuss the code's applicability to comets.

  11. Spin resonance strength calculation through single particle tracking for RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Dutheil, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States); Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ranjbar, V. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-05-03

    The strengths of spin resonances for the polarized-proton operation in the Relativistic Heavy Ion Collider are currently calculated with the code DEPOL, which numerically integrates through the ring based on an analytical approximate formula. In this article, we test a new way to calculate the spin resonance strengths by performing Fourier transformation to the actual transverse magnetic fields seen by a single particle traveling through the ring. Comparison of calculated spin resonance strengths is made between this method and DEPOL.

  12. Dark-field scanning confocal microscope for vertical particle tracks in nuclear emulsion

    International Nuclear Information System (INIS)

    The principle of the DArk-FIeld Scanning CONfocal (DAFISCON) microscope for selective observation of the vertical particle tracks in nuclear emulsion is described. The construction of the DAFISCON microscope, built on the basis of the 2D measurement microscope, is described. The results of the experimental testing of the DAFISCON microscope, accomplished at high density of the vertical particle tracks, are presented. The 2D plot and the 1D plot of the CCD dark-field image are given. The spatial resolution of our microscope can be increased by using the objective with higher aperture

  13. Alpha particles energy estimation from track diameter development in a CR-39 detector.

    Science.gov (United States)

    Azooz, Aassim A; Al-Jubbori, Mushtaq A

    2016-09-01

    The slight nonlinearity in temporal development of tracks diameter in CR-39 nuclear track detectors is examined with the aim of attempting to find if such nonlinearity can be directly related to the charged particle energy. Narrowly spaced etching time-diameter experimental data for alpha particles at five energy values and for one additional energy value etched at five different temperatures are obtained. Initial results show good indication that measuring such time-diameter relationship can form a useful energy estimation tool. Good consistency with other independent published results is obtained. PMID:27341133

  14. MOTION OF TRACER PARTICLES IN A CENTRIFUGAL PUMP AND ITS TRACKING CHARACTERISTICS

    Institute of Scientific and Technical Information of China (English)

    LI Ya-lin; YUAN Shou-qi; TANG Yue; YUAN Jian-ping

    2012-01-01

    The Basset-Boussinesq-Oseen (BBO) equation can be used for most flows to trace the motion of a particle,but in a centrifugal pump,among the forces that act on the particles,one should also include those due to the impeller rotation,as additional effects.This paper firstly reviews various approximations of the BBO equation for the motion of dispersion particles in a viscous fluid.Then based on the motion equation for particles in low Reynolds number centrifugal pumps,a formula for calculating the tracking characteristics of tracer particles is deduced through the Fourier integral transformation.After that the deviations of the particle motion from the fluid motion,as predicted by the various approximations,are discussed and compared.At last,with an emphasis on the Particle Image Velocimetry (PIV) results,the tracking characteristics of particles are estimated.Also,advantages and disadvantages of different tracer particles are discussed and suitable tracer particles for application in PIV studies for flow fields in centrifugal pumps are suggested.

  15. Optical imaging of charged particle tracks in a gas. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Turner, J.E.; Hamn, R.N. [Oak Ridge National Lab., TN (United States); Hunter, S.R.; Gibson, W.A.; Hurst, G.S. [Pellissippi International, Inc., Oak Ridge, TN (United States); Wright, H.A. [Consultec Scientific, Inc., Knoxville, TN (United States)

    1995-09-28

    The development of a new detector designed to optically image the track of a charged particle in a gas is outlined. In the detector, a pulsed high-voltage (up to {approx} 30--40 kV), high-frequency (f = 27.125 MHz) RF field is temporarily applied (pulse duration {approx} 1--3 {mu}s) across a pair of electrodes, immediately following, or alternatively, just prior to the passage of a charged particle through the chamber. The pulsed RF field excites the subexcitation electrons left along the particle`s path leading to excitation and ionization of the surrounding gas and the emission of light. The track is then imaged by a fast intensified digital camera (shutter speed {approx} 0.1--5 {mu}s). The image is recorded in a two-dimensional pixel array (512 {times} 512 pixels) within the camera, and transferred to a computer for later analysis. The detector has been operated over the total gas pressure range 2.5--100 kPa (20--750 torr) using a gas mixture of 2--10% N2 in Ar. Images of both {alpha} and {beta} tracks obtained with this detector are discussed to demonstrate the usefulness of the present technique in charged-particle track analysis for dosimetry and microdosimetry applications.

  16. Electrochemical etching amplification of low-let recoil particle tracks in polymers for fast neutron dosimetry

    International Nuclear Information System (INIS)

    An electrochemical etching method for the amplification of fast-neutron-induced recoil particle tracks in polymers was investigated. The technique gave superior results over those obtained by conventional etching methods especially when polycarbonate foils were used for recoil particle track amplification. Electrochemical etching systems capable of multi-foil processing were designed and constructed to demonstrate the feasibility of the techniques for large-scale neutron dosimetry. Electrochemical etching parameters were studied including the nature or type of the polymer foil used, foil thickness and its effect on etching time, the applied voltage and its frequency, the chemical composition, concentration, and temperature of the etchant, distance and angle between the electrodes, and the type of particles such as recoil particles including protons. Recoil particle track density, mean track diameter, and optical density as functions of the mentioned parameters were determined. Each parameter was found to have a distinct effect on the etching results in terms of the measured responses. Several new characteristics of this fast neutron dosimetry method were studied especially for personnel dosimetry using various radiation sources such as nuclear reactors, medical cyclotrons, and isotopic neutron sources. The dose range, neutron energy dependence, directional response, fading characteristics, neutron threshold energy, etc. were investigated

  17. Local weighting of nanometric track structure properties in macroscopic voxel geometries for particle beam treatment planning

    Science.gov (United States)

    Alexander, F.; Villagrasa, C.; Rabus, H.; Wilkens, J. J.

    2015-12-01

    The research project BioQuaRT within the European Metrology Research Programme aimed at correlating ion track structure characteristics with the biological effects of radiation and developed measurement and simulation techniques for determining ion track structure on different length scales from about 2 nm to about 10 μm. Within this framework, we investigated methods to translate track-structure quantities derived on a nanometre scale to macroscopic dimensions. Here we make use of parameterizations that link the energy of the projectile to the ionization pattern of the track using nanodosimetric ionization cluster size distributions. They were defined with data generated by simulations of ion tracks in liquid water using the Geant4 Monte Carlo toolkit with the Geant4-DNA processes. For the clinical situation with a mixed radiation field, where particles of various energies hit a cell from several directions, we have to find macroscopic relevant mean values. They can be determined by appropriate local weighting functions for the identified parameterization. We show that a stopping power weighted mean value of the mentioned track structure properties can describe the overall track structure in a cell exposed to a mixed radiation field. The parameterization, together with the presented stopping power weighting approach, show how nanometric track structure properties could be integrated into treatment planning systems without the need to perform time consuming simulations on the nanometer level for each individual patient.

  18. Holographic time-resolved particle tracking by means of three-dimensional volumetric deconvolution

    CERN Document Server

    Latychevskaia, Tatiana

    2014-01-01

    Holographic particle image velocimetry allows tracking particle trajectories in time and space by means of holography. However, the drawback of the technique is that in the three-dimensional particle distribution reconstructed from a hologram, the individual particles can hardly be resolved due to the superimposed out-of-focus signal from neighboring particles. We demonstrate here a three-dimensional volumetric deconvolution applied to the reconstructed wavefront which results in resolving all particles simultaneously in three-dimensions. Moreover, we apply the three-dimensional volumetric deconvolution to reconstructions of a time-dependent sequence of holograms of an ensemble of polystyrene spheres moving in water. From each hologram we simultaneously resolve all particles in the ensemble in three dimensions and from the sequence of holograms we obtain the time-resolved trajectories of individual polystyrene spheres.

  19. Long-term tracking of neutrally buoyant tracer particles in two-dimensional fluid flows

    Science.gov (United States)

    Pervez, M. S.; Solomon, T. H.

    1994-07-01

    An experimental technique has been developed to produce and to track neutrally buoyant particles in a two-dimensional fluid flow. The key aspect of the technique is the ability to track particles for extended intervals (over an hour), which is essential for quantitative studies of transport and mixing. The approach is composed of two stages. In the first stage, digital image processing hardware partially processes the images, reducing the data rate to 50 kbyte/s (typically) and allowing several hours of data to be stored on a conventional computer disk. In the second stage, programs extract particle trajectories from the reduced data. The approach is tested in an experiment on planetary-type flows in a rotating annulus. In an appendix, a technique is discussed for fabricating wax or crayon particles with arbitrary density.

  20. A transition radiation detector for RHIC featuring accurate tracking and dE/dx particle identification

    Energy Technology Data Exchange (ETDEWEB)

    O`Brien, E.; Lissauer, D.; McCorkle, S.; Polychronakos, V.; Takai, H. [Brookhaven National Lab., Upton, NY (United States); Chi, C.Y.; Nagamiya, S.; Sippach, W.; Toy, M.; Wang, D.; Wang, Y.F.; Wiggins, C.; Willis, W. [Columbia Univ., New York, NY (United States); Cherniatin, V.; Dolgoshein, B. [Moscow Institute of Physics and Engineering, (Russian Federation); Bennett, M.; Chikanian, A.; Kumar, S.; Mitchell, J.T.; Pope, K. [Yale Univ., New Haven, CT (United States)

    1991-12-31

    We describe the results of a test ran involving a Transition Radiation Detector that can both distinguish electrons from pions which momenta greater titan 0.7 GeV/c and simultaneously track particles passing through the detector. The particle identification is accomplished through a combination of the detection of Transition Radiation from the electron and the differences in electron and pion energy loss (dE/dx) in the detector. The dE/dx particle separation is most, efficient below 2 GeV/c while particle ID utilizing Transition Radiation effective above 1.5 GeV/c. Combined, the electron-pion separation is-better than 5 {times} 10{sup 2}. The single-wire, track-position resolution for the TRD is {approximately}230 {mu}m.

  1. 3D tracking the Brownian motion of colloidal particles using digital holographic microscopy and joint reconstruction

    CERN Document Server

    Verrier, Nicolas; Fournel, Thierry

    2015-01-01

    In-line digital holography is a valuable tool for sizing, locating and tracking micro- or nano-objects in a volume. When a parametric imaging model is available, Inverse Problems approaches provide a straightforward estimate of the object parameters by fitting data with the model, thereby allowing accurate reconstruction. As recently proposed and demonstrated, combining pixel super-resolution techniques with Inverse Problems approaches improves the estimation of particle size and 3D-position. Here we demonstrate the accurate tracking of colloidal particles in Brownian motion. Particle size and 3D-position are jointly optimized from video holograms acquired with a digital holographic microscopy set up based on a "low-end" microscope objective ($\\times 20$, $\\rm NA\\ 0.5$). Exploiting information redundancy makes it possible to characterize particles with a standard deviation of 15 nm in size and a theoretical resolution of 2 x 2 x 5 nm$^3$ for position under additive white Gaussian noise assumption.

  2. A new positron emission particle tracking facility at iThemba LABS

    International Nuclear Information System (INIS)

    Positron emission particle tracking (PEPT) has become a powerful tool for in-situ characterisation and visualization of particulate flow within aggressive industrial environments, such as tumbling mills and powder mixers. PEPT is based on the tracking of a single tracer particle which has been labelled with a radionuclide that decays via beta-plus decay. The location of the particle is obtained by the triangulation of events associated with the detection of pairs of annihilation gamma rays in a modified 'positron camera.' One of the challenges facing PEPT is associated with labelling particles smaller than 100 μm which would allow studies in systems of finer particulate flow, such as flotation cells. The Positron Imaging Centre at the University of Birmingham is currently the only operational PEPT facility in the world. PEPT Cape Town will shortly become operational at iThemba LABS, South Africa. (author)

  3. Redundant Asynchronous Microprocessor System

    Science.gov (United States)

    Meyer, G.; Johnston, J. O.; Dunn, W. R.

    1985-01-01

    Fault-tolerant computer structure called RAMPS (for redundant asynchronous microprocessor system) has simplicity of static redundancy but offers intermittent-fault handling ability of complex, dynamically redundant systems. New structure useful wherever several microprocessors are employed for control - in aircraft, industrial processes, robotics, and automatic machining, for example.

  4. Asynchronous P300 BCI

    DEFF Research Database (Denmark)

    Panicker, Rajesh; Puthusserypady, Sadasivan; Sun, Ying

    2010-01-01

    An asynchronous hybrid brain-computer interface (BCI) system combining the P300 and steady-state visually evoked potentials (SSVEP) paradigms is introduced. A P300 base system is used for information transfer, and is augmented to include SSVEP for control state detection. The proposed system has...

  5. Probabilistic Data Association-Feedback Particle Filter for Multiple Target Tracking Applications

    OpenAIRE

    Yang, Tao; Mehta, Prashant G.

    2014-01-01

    This paper is concerned with the problem of tracking single or multiple targets with multiple non-target specific observations (measurements). For such filtering problems with data association uncertainty, a novel feedback control-based particle filter algorithm is introduced. The algorithm is referred to as the probabilistic data association-feedback particle filter (PDA-FPF). The proposed filter is shown to represent a generalization to the nonlinear non-Gaussian case of the classical Kalma...

  6. High throughput on-chip analysis of high-energy charged particle tracks using lensfree imaging

    International Nuclear Information System (INIS)

    We demonstrate a high-throughput charged particle analysis platform, which is based on lensfree on-chip microscopy for rapid ion track analysis using allyl diglycol carbonate, i.e., CR-39 plastic polymer as the sensing medium. By adopting a wide-area opto-electronic image sensor together with a source-shifting based pixel super-resolution technique, a large CR-39 sample volume (i.e., 4 cm × 4 cm × 0.1 cm) can be imaged in less than 1 min using a compact lensfree on-chip microscope, which detects partially coherent in-line holograms of the ion tracks recorded within the CR-39 detector. After the image capture, using highly parallelized reconstruction and ion track analysis algorithms running on graphics processing units, we reconstruct and analyze the entire volume of a CR-39 detector within ∼1.5 min. This significant reduction in the entire imaging and ion track analysis time not only increases our throughput but also allows us to perform time-resolved analysis of the etching process to monitor and optimize the growth of ion tracks during etching. This computational lensfree imaging platform can provide a much higher throughput and more cost-effective alternative to traditional lens-based scanning optical microscopes for ion track analysis using CR-39 and other passive high energy particle detectors

  7. High throughput on-chip analysis of high-energy charged particle tracks using lensfree imaging

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Wei; Shabbir, Faizan; Gong, Chao; Gulec, Cagatay; Pigeon, Jeremy; Shaw, Jessica; Greenbaum, Alon; Tochitsky, Sergei; Joshi, Chandrashekhar [Electrical Engineering Department, University of California, Los Angeles, California 90095 (United States); Ozcan, Aydogan, E-mail: ozcan@ucla.edu [Electrical Engineering Department, University of California, Los Angeles, California 90095 (United States); Bioengineering Department, University of California, Los Angeles, California 90095 (United States); California NanoSystems Institute (CNSI), University of California, Los Angeles, California 90095 (United States)

    2015-04-13

    We demonstrate a high-throughput charged particle analysis platform, which is based on lensfree on-chip microscopy for rapid ion track analysis using allyl diglycol carbonate, i.e., CR-39 plastic polymer as the sensing medium. By adopting a wide-area opto-electronic image sensor together with a source-shifting based pixel super-resolution technique, a large CR-39 sample volume (i.e., 4 cm × 4 cm × 0.1 cm) can be imaged in less than 1 min using a compact lensfree on-chip microscope, which detects partially coherent in-line holograms of the ion tracks recorded within the CR-39 detector. After the image capture, using highly parallelized reconstruction and ion track analysis algorithms running on graphics processing units, we reconstruct and analyze the entire volume of a CR-39 detector within ∼1.5 min. This significant reduction in the entire imaging and ion track analysis time not only increases our throughput but also allows us to perform time-resolved analysis of the etching process to monitor and optimize the growth of ion tracks during etching. This computational lensfree imaging platform can provide a much higher throughput and more cost-effective alternative to traditional lens-based scanning optical microscopes for ion track analysis using CR-39 and other passive high energy particle detectors.

  8. Micro-object motion tracking based on the probability hypothesis density particle tracker.

    Science.gov (United States)

    Shi, Chunmei; Zhao, Lingling; Wang, Junjie; Zhang, Chiping; Su, Xiaohong; Ma, Peijun

    2016-04-01

    Tracking micro-objects in the noisy microscopy image sequences is important for the analysis of dynamic processes in biological objects. In this paper, an automated tracking framework is proposed to extract the trajectories of micro-objects. This framework uses a probability hypothesis density particle filtering (PF-PHD) tracker to implement a recursive state estimation and trajectories association. In order to increase the efficiency of this approach, an elliptical target model is presented to describe the micro-objects using shape parameters instead of point-like targets which may cause inaccurate tracking. A novel likelihood function, not only covering the spatiotemporal distance but also dealing with geometric shape function based on the Mahalanobis norm, is proposed to improve the accuracy of particle weight in the update process of the PF-PHD tracker. Using this framework, a larger number of tracks are obtained. The experiments are performed on simulated data of microtubule movements and real mouse stem cells. We compare the PF-PHD tracker with the nearest neighbor method and the multiple hypothesis tracking method. Our PF-PHD tracker can simultaneously track hundreds of micro-objects in the microscopy image sequence. PMID:26084407

  9. Calibrations for Charged Particle Tracking with the GlueX Detector

    Science.gov (United States)

    Staib, Michael; GlueX Collaboration

    2015-10-01

    Two gas detectors comprise the tracking system for the GlueX experiment, the Central Drift Chamber (CDC) and the Forward Drift Chamber (FDC). The CDC is a cylindrical straw-tube detector covering polar angles between 6° and 168°, delivering spatial resolution of ~150 μm. The FDC is a Cathode Strip Chamber consisting of four packages, each with six alternating layers of anode wires and cathode strips. The FDC is designed to track forward-going charged particles with polar angles between 1° and 20° with a spatial resolution of ~200 μm. Both tracking detectors record timing information and energy loss measurements useful for particle identification. During Fall 2014 and Spring 2015, the first photon beam was delivered on target for commissioning of the GlueX detector in Hall-D at Jefferson Lab. These data are currently being used in a large effort to calibrate the individual detector subsystems to achieve design performance. Methods and results for calibrations of each of the tracking detectors are presented. Techniques for alignment of the tracking system using a combination of cosmic rays and beam data is discussed. Finally, some early results of physics measurements including charged final-state particles are presented. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Contract DE-AC05-06OR23177.

  10. 3D head pose estimation and tracking using particle filtering and ICP algorithm

    KAUST Repository

    Ben Ghorbel, Mahdi

    2010-01-01

    This paper addresses the issue of 3D head pose estimation and tracking. Existing approaches generally need huge database, training procedure, manual initialization or use face feature extraction manually extracted. We propose a framework for estimating the 3D head pose in its fine level and tracking it continuously across multiple Degrees of Freedom (DOF) based on ICP and particle filtering. We propose to approach the problem, using 3D computational techniques, by aligning a face model to the 3D dense estimation computed by a stereo vision method, and propose a particle filter algorithm to refine and track the posteriori estimate of the position of the face. This work comes with two contributions: the first concerns the alignment part where we propose an extended ICP algorithm using an anisotropic scale transformation. The second contribution concerns the tracking part. We propose the use of the particle filtering algorithm and propose to constrain the search space using ICP algorithm in the propagation step. The results show that the system is able to fit and track the head properly, and keeps accurate the results on new individuals without a manual adaptation or training. © Springer-Verlag Berlin Heidelberg 2010.

  11. 基于强跟踪滤波算法的异步电机参数自适应无速度传感器控制%Parameter Adaptation Sensorless Control of Asynchronous Motor Based on Strong Track Filter

    Institute of Scientific and Technical Information of China (English)

    陆可

    2011-01-01

    在异步电机四阶模型的基础上增加机械和转矩方程,并引入负载转矩和转子电阻为状态变量,得到七阶非线性模型.利用强跟踪滤波(STF)算法实现电机状态和转子电阻的同时估计,通过仿真比较了STF和扩展Kalman滤波(EKF)算法的估计性能.结果表明,STF算法能有效估计电机状态及辨识转子电阻,并且具有比EKF算法更理想的估计性能,同时能满足极低速和零速下的估计要求,从而在电机的整个工作范围内实现转子电阻自适应的状态估计.%The equations of machine and torque were added to the fourth-order model of asynchronous motor.A seventh-order nonlinear model was obtained via increasing load torque and rotor resistance as state variables.The motor states and the rotor resistance were estimated simultaneously using strong track filter (STF).Computer simulations were performed to compare the estimation performance between STF and EKF.The results illustrated that STF could estimate the motor states and the rotor resistance effectively, and its performance was more perfect than EKF' s.STF could also satisfy the estimation request running at very low and zero speed, thus it could realize the states estimation with rotor resistance adaptation in the whole operation range.

  12. Correlation of Particle Traversals with Clonogenic Survival Using Cell-Fluorescent Ion Track Hybrid Detector

    Directory of Open Access Journals (Sweden)

    Ivana eDokic

    2015-12-01

    Full Text Available Development of novel approaches linking the physical characteristics of particles with biological responses are of high relevance for the field of particle therapy. In radiobiology, the clonogenic survival of cells is considered the gold standard assay for assessment of cellular sensitivity to ionizing radiation. Towards further development of next generation biodosimeters in particle therapy, cell-fluorescent ion track hybrid detector (Cell-FIT-HD was recently engineered by our group and successfully employed to study physical particle track information in correlation with irradiation- induced DNA damage in cell nuclei. In this work, we investigated the feasibility of Cell-FIT-HD as a tool to study the effects of clinical beams on cellular clonogenic survival. Tumor cells were grown on the FNTD as cell culture, mimicking the standard procedures for clonogenic assay. Cell-FIT-HD was used to detect the spatial distribution of particle tracks within colony-initiating cells. The physical data were associated to radiation induced foci as surrogates for DNA double strand breakages (DSB, the hallmark of radiation ‐induced cell lethality. Long‐term cell fate was monitored to determine the ability of cells to form colonies. We report the first successful detection of particle traversal within colony-initiating cells at subcellular resolution using Cell-FIT-HD.

  13. High energy particle tracking using scintillating fibers and solid state photomultipliers

    International Nuclear Information System (INIS)

    The Solid State Photomultiplier (SSPM) recently developed at the Rockwell International Science Center, coupled with fast scintillating fibers can have a rate capacity of 108 tracks per second per cm2 of fiber cross section in systems for tracking of high energy ionizing particles. Relative to other approaches the SSPM can provide substantial improvements in spatial and temporal tracking accuracy. Results of preliminary experiments with 0.225 /times/ 0.225 mm2 cross section step-index-of-refraction fiber exposed to electrons from a beta source are presented. The experiments involved pulse height analysis of SSPM photon detection pulses induced by coincident scintillations in two adjacent fibers traversed by the same electron. The data for two different scintillating fibers tested indicate that meter long fibers of this type, optimally coupled to SSPMs, will be effective in detecting minimum ionizing particles. 4 refs., 3 figs., 1 tab

  14. Charged particle tracking through electrostatic wire meshes using the finite element method

    Science.gov (United States)

    Devlin, L. J.; Karamyshev, O.; Welsch, C. P.

    2016-06-01

    Wire meshes are used across many disciplines to accelerate and focus charged particles, however, analytical solutions are non-exact and few codes exist which simulate the exact fields around a mesh with physical sizes. A tracking code based in Matlab-Simulink using field maps generated using finite element software has been developed which tracks electrons or ions through electrostatic wire meshes. The fields around such a geometry are presented as an analytical expression using several basic assumptions, however, it is apparent that computational calculations are required to obtain realistic values of electric potential and fields, particularly when multiple wire meshes are deployed. The tracking code is flexible in that any quantitatively describable particle distribution can be used for both electrons and ions as well as other benefits such as ease of export to other programs for analysis. The code is made freely available and physical examples are highlighted where this code could be beneficial for different applications.

  15. Particle filter based visual tracking with multi-cue adaptive fusion

    Institute of Scientific and Technical Information of China (English)

    Anping Li; Zhongliang Jing; Shiqiang Hu

    2005-01-01

    @@ To improve the robustness of visual tracking in complex environments such as: cluttered backgrounds, partial occlusions, similar distraction and pose variations, a novel tracking method based on adaptive fusion and particle filter is proposed in this paper. In this method, the image color and shape cues are adaptively fused to represent the target observation; fuzzy logic is applied to dynamically adjust each cue weight according to its associated reliability in the past frame; particle filter is adopted to deal with non-linear and non-Gaussian problems in visual tracking. The method is demonstrated to be robust to illumination changes, pose variations, partial occlusions, cluttered backgrounds and camera motion for a test image sequence.

  16. Optical imaging of charged particle tracks in a gas. Final report

    International Nuclear Information System (INIS)

    The development of a new detector designed to optically image the track of a charged particle in a gas is outlined. In the detector, a pulsed high-voltage (up to ∼ 30--40 kV), high-frequency (f = 27.125 MHz) RF field is temporarily applied (pulse duration ∼ 1--3 μs) across a pair of electrodes, immediately following, or alternatively, just prior to the passage of a charged particle through the chamber. The pulsed RF field excites the subexcitation electrons left along the particle's path leading to excitation and ionization of the surrounding gas and the emission of light. The track is then imaged by a fast intensified digital camera (shutter speed ∼ 0.1--5 μs). The image is recorded in a two-dimensional pixel array (512 x 512 pixels) within the camera, and transferred to a computer for later analysis. The detector has been operated over the total gas pressure range 2.5--100 kPa (20--750 torr) using a gas mixture of 2--10% N2 in Ar. Images of both α and β tracks obtained with this detector are discussed to demonstrate the usefulness of the present technique in charged-particle track analysis for dosimetry and microdosimetry applications

  17. Particle filtering for obstacle tracking in UAS sense and avoid applications.

    Science.gov (United States)

    Tirri, Anna Elena; Fasano, Giancarmine; Accardo, Domenico; Moccia, Antonio

    2014-01-01

    Obstacle detection and tracking is a key function for UAS sense and avoid applications. In fact, obstacles in the flight path must be detected and tracked in an accurate and timely manner in order to execute a collision avoidance maneuver in case of collision threat. The most important parameter for the assessment of a collision risk is the Distance at Closest Point of Approach, that is, the predicted minimum distance between own aircraft and intruder for assigned current position and speed. Since assessed methodologies can cause some loss of accuracy due to nonlinearities, advanced filtering methodologies, such as particle filters, can provide more accurate estimates of the target state in case of nonlinear problems, thus improving system performance in terms of collision risk estimation. The paper focuses on algorithm development and performance evaluation for an obstacle tracking system based on a particle filter. The particle filter algorithm was tested in off-line simulations based on data gathered during flight tests. In particular, radar-based tracking was considered in order to evaluate the impact of particle filtering in a single sensor framework. The analysis shows some accuracy improvements in the estimation of Distance at Closest Point of Approach, thus reducing the delay in collision detection. PMID:25105154

  18. Particle Filtering for Obstacle Tracking in UAS Sense and Avoid Applications

    Directory of Open Access Journals (Sweden)

    Anna Elena Tirri

    2014-01-01

    Full Text Available Obstacle detection and tracking is a key function for UAS sense and avoid applications. In fact, obstacles in the flight path must be detected and tracked in an accurate and timely manner in order to execute a collision avoidance maneuver in case of collision threat. The most important parameter for the assessment of a collision risk is the Distance at Closest Point of Approach, that is, the predicted minimum distance between own aircraft and intruder for assigned current position and speed. Since assessed methodologies can cause some loss of accuracy due to nonlinearities, advanced filtering methodologies, such as particle filters, can provide more accurate estimates of the target state in case of nonlinear problems, thus improving system performance in terms of collision risk estimation. The paper focuses on algorithm development and performance evaluation for an obstacle tracking system based on a particle filter. The particle filter algorithm was tested in off-line simulations based on data gathered during flight tests. In particular, radar-based tracking was considered in order to evaluate the impact of particle filtering in a single sensor framework. The analysis shows some accuracy improvements in the estimation of Distance at Closest Point of Approach, thus reducing the delay in collision detection.

  19. Mica track microfilters applied in a cascade particle fractionator at an industrial plant

    International Nuclear Information System (INIS)

    Mica Track Microfilters (MTM) are produced by irradiation of mica discs with heavy ions. The air throughput dV/dt is investigated experimentally within the temperature range 20 deg C <= T <= 300 deg C and described by a simple formula. MTM are placed in a Cascade Particle Fractionator and applied in the filtration of hot and radioactive gas under industrial conditions. (author)

  20. Preliminary Study of Natural Alpha Particle Track Areal Distribution Behind Eyeglasses Obstacles

    International Nuclear Information System (INIS)

    Plastic nuclear track detectors are widely used to register tracks of alpha particles emitted from radon gas nuclei and radioactive daughter nuclei. Eye glasses, finger rings, necklaces and many other accessories intimately accompany most people. The eyeglasses may modify the surface distribution of alpha particle pass spots just behind them. There may be some effects due to the earth's magnetic field on the motion of the charged alpha particle emitters (radon ions). In metallic frames of the eyeglasses, the earth's magnetic field and charged radio-ions enforce free electrons to move setting electric current, which reduces the magnetic field at the frame. Being weak at the frame and stronger on both sides away, the magnetic field lines may form a magnetic trap of some charged radio-ions in the air. The polymer Solid State Nuclear Track Detector (SSNTD) CR-39 which is a polyalyl diglycol carbonate is used to register alpha particles behind the eyeglasses obstacles. Remarkable decrease in alpha track density was noticed in CR-39 registration due both to glass and magnetic screening. The obtained results call for more studies on all metallic tools used or possessed in mines and non-ventilated underground cavities.

  1. Test of scintillating bars coupled to Silicon Photomultipliers for a charged particle tracking device

    CERN Document Server

    Cecchini, S; Esposti, L Degli; Lax, I; Mandrioli, G; Mauri, N; Pasqualini, L; Patrizii, L; Pozzato, M; Sirri, G; Tenti, M

    2016-01-01

    The results obtained in laboratory tests, using scintillator bars read by silicon photomultipliers are reported. The present approach is the first step for designing a precision tracking system to be placed inside a free magnetized volume for the charge identification of low energy crossing particles. The devised system is demonstrated able to provide a spatial resolution better than 2 mm.

  2. Micro-heterogeneity of corn hulls cellulosic fiber biopolymer studied by multiple-particle tracking (MPT)

    Science.gov (United States)

    A novel technique named multiple-particle tracking (MPT) was used to investigate the micro-structural heterogeneities of Z-trim, a zero calorie cellulosic fiber biopolymer produced from corn hulls. The principle of MPT technique is to monitor the thermally driven motion of inert micro-spheres, which...

  3. Multiple Maneuvering Target Tracking by Improved Particle Filter Based on Multiscan JPDA

    Directory of Open Access Journals (Sweden)

    Jing Liu

    2012-01-01

    Full Text Available The multiple maneuvering target tracking algorithm based on a particle filter is addressed. The equivalent-noise approach is adopted, which uses a simple dynamic model consisting of target state and equivalent noise which accounts for the combined effects of the process noise and maneuvers. The equivalent-noise approach converts the problem of maneuvering target tracking to that of state estimation in the presence of nonstationary process noise with unknown statistics. A novel method for identifying the nonstationary process noise is proposed in the particle filter framework. Furthermore, a particle filter based multiscan Joint Probability Data Association (JPDA filter is proposed to deal with the data association problem in a multiple maneuvering target tracking. In the proposed multiscan JPDA algorithm, the distributions of interest are the marginal filtering distributions for each of the targets, and these distributions are approximated with particles. The multiscan JPDA algorithm examines the joint association events in a multiscan sliding window and calculates the marginal posterior probability based on the multiscan joint association events. The proposed algorithm is illustrated via an example involving the tracking of two highly maneuvering, at times closely spaced and crossed, targets, based on resolved measurements.

  4. Kalman-Filter-Based Particle Tracking on Parallel Architectures at Hadron Colliders

    CERN Document Server

    Cerati, Giuseppe; Lantz, Steven; McDermott, Kevin; Riley, Dan; Tadel, Matevž; Wittich, Peter; Würthwein, Frank; Yagil, Avi

    2016-01-01

    Power density constraints are limiting the performance improvements of modern CPUs. To address this we have seen the introduction of lower-power, multi-core processors such as GPGPU, ARM and Intel MIC. To stay within the power density limits but still obtain Moore's Law performance/price gains, it will be necessary to parallelize algorithms to exploit larger numbers of lightweight cores and specialized functions like large vector units. Track finding and fitting is one of the most computationally challenging problems for event reconstruction in particle physics. At the High-Luminosity Large Hadron Collider (HL-LHC), for example, this will be by far the dominant problem. The need for greater parallelism has driven investigations of very different track finding techniques such as Cellular Automata or Hough Transforms. The most common track finding techniques in use today, however, are those based on the Kalman Filter. Significant experience has been accumulated with these techniques on real tracking detector sy...

  5. Automatic track recognition for large-angle minimum ionizing particles in nuclear emulsions

    CERN Document Server

    Fukuda, T; Ishida, H; Matsumoto, T; Matsuo, T; Mikado, S; Nishimura, S; Ogawa, S; Shibuya, H; Sudou, J; Ariga, A; Tufanli, S

    2014-01-01

    We previously developed an automatic track scanning system which enables the detection of large-angle nuclear fragments in the nuclear emulsion films of the OPERA experiment. As a next step, we have investigated this system's track recognition capability for large-angle minimum ionizing particles $(1.0 \\leq |tan \\theta| \\leq 3.5)$. This paper shows that, for such tracks, the system has a detection efficiency of 95$\\%$ or higher and reports the achieved angular accuracy of the automatically recognized tracks. This technology is of general purpose and will likely contribute not only to various analyses in the OPERA experiment, but also to future experiments, e.g. on low-energy neutrino and hadron interactions, or to future research on cosmic rays using nuclear emulsions carried by balloons.

  6. Automatic track recognition for large-angle minimum ionizing particles in nuclear emulsions

    International Nuclear Information System (INIS)

    We previously developed an automatic track scanning system which enables the detection of large-angle nuclear fragments in the nuclear emulsion films of the OPERA experiment. As a next step, we have investigated this system's track recognition capability for large-angle minimum ionizing particles (1.0 ≤ |tan θ| ≤ 3.5). This paper shows that, for such tracks, the system has a detection efficiency of 95% or higher and reports the achieved angular accuracy of the automatically recognized tracks. This technology is of general purpose and will likely contribute not only to various analyses in the OPERA experiment, but also to future experiments, e.g. on low-energy neutrino and hadron interactions, or to future research on cosmic rays using nuclear emulsions carried by balloons

  7. Guitarist Fingertip Tracking by Integrating a Bayesian Classifier into Particle Filters

    Directory of Open Access Journals (Sweden)

    Chutisant Kerdvibulvech

    2008-01-01

    Full Text Available We propose a vision-based method for tracking guitar fingerings made by guitar players. We present it as a new framework for tracking colored finger markers by integrating a Bayesian classifier into particle filters. This adds the useful abilities of automatic track initialization and recovery from tracking failures in a dynamic background. Furthermore, by using the online adaptation of color probabilities, this method is able to cope with illumination changes. Augmented Reality Tag (ARTag is then utilized to calculate the projection matrix as an online process which allows the guitar to be moved while being played. Representative experimental results are also included. The method presented can be used to develop the application of human-computer interaction (HCI to guitar playing by recognizing the chord being played by a guitarist in virtual spaces. The aforementioned application would assist guitar learners by allowing them to automatically identify if they are using the correct chords required by the musical piece.

  8. Geometrical parameters of tracks registered by collimated alpha particles on CR-39 detector

    International Nuclear Information System (INIS)

    The latent tracks formed on CR-39 solid state track detector on exposure of alpha radiations emanating from a collimated 241Am source were developed by a chemical etching method. Alpha track images were captured by an optical microscope and were processed by using Image Pro-Plus (6.0) software. GEANT4 simulations were carried out to obtain the angular and energy distribution profiles of the alpha particles. Apart from fluence, geometric parameters like aspect ratio (the ratio of the major to minor axis) and the depth profiles of etched tracks were measured experimentally and correlated with simulated angular and energy profile of incident radiations. Reasonable agreement was observed in the fluence and depth profile information obtained from experiments and simulations

  9. Age and uranium content of soil micas from Antarctica by the fission particle track replica method

    International Nuclear Information System (INIS)

    A replica method was developed for fission particle track age dating and determination of uranium content of micas in a Wright Valley, Antarctica, soil and parent rock. The mica particles in the soil were relatively small, fragile, and easily dissolved by chemical etchings. Muscovite mica flakes were therefore used as a replicating substrate to register induced fission tracks of the soil mica. The micas from three soil horizons (0 to 10, 10 to 30, and 30 to 50 cm depths) and parent rock, in four size fractions (100 to 500, 2 to 5, 0.2 to 2, and <0.2μm) were examined to illustrate use of the method. The fission track age of the soil mica particles was 4.1 +- 0.2 million years (MY), slightly older than the minimum landscape (glacial bench) age of 3.7 +- 0.2 MY obtained previously by K-Ar dating of a volcanic cone formed after the glacial valley was formed. The ages of the 2 to 5, 0.2 to 2, and <0.2μm fractions were the same as for the 100 to 500 μm flakes, when the spontaneous track density was calculated from that of the latter, in proportion to the U content. The fission track age of parent rock mica was 151 million years. The U content of the soil mica was 0.5 to 1.6 ppM which is 20 to 50 times higher than that of mica from the parent rock (0.03 ppM). The mica in the soil appears from age and petrographic thin-section results to be of pedogenic origin, formed by replacement in feldspars after the bench was carved. The fission particle track replica method is useful for age-dating of micas in soils, for determining trace amounts of uranium in micas, and for study of soil genesis in the Antarctic cold desert

  10. Innovative Method Using Magnetic Particle Tracking to Measure Solids Circulation in a Spouted Bed

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, Ms. Emily [Waynesburg University; Halow, John [Waynesburg University; Daw, C Stuart [ORNL

    2010-01-01

    We describe an innovative method for measuring particle motion inside spouted fluidized beds. The method uses a magnetic tracer particle, which follows the bulk particle flow and is continuously tracked by multiple magnetic field detectors located outside the bed. We analyze signals from the detectors to determine the tracer position at each instant in time. From statistical analysis of the tracer trajectory, characteristic measures of the bulk particle flow, such as the average recirculation frequency, can be determined as a function of operating conditions. For experiments with a range of particle sizes and densities in a 3.9-cm-diameter spouted bed, we find that average solids recirculation rates correlate with excess velocity (superficial minus minimum spouting velocity), particle density, and bed depth.

  11. Innovative method using magnetic particle tracking to measure solids circulation in a spouted fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, Ms. Emily [Waynesburg University; Halow, John [Waynesburg University; Daw, C Stuart [ORNL

    2009-01-01

    We describe an innovative method for measuring particle motion inside spouted fluidized beds. The method uses a magnetic tracer particle, which follows the bulk particle flow and is continuously tracked by multiple magnetic field detectors located outside the bed. We analyze signals from the detectors to determine the tracer position at each instant in time. From statistical analysis of the tracer trajectory, characteristic measures of the bulk particle flow, such as the average recirculation frequency, can be determined as a function of operating conditions. For experiments with a range of particle sizes and densities in a 3.9-cm-diameter spouted bed, we find that average solids recirculation rates correlate with excess velocity (superficial minus minimum spouting velocity), particle density, and bed depth.

  12. A parallel implementation of particle tracking with space charge effects on an Intel iPSC/860

    International Nuclear Information System (INIS)

    Particle-tracking simulation is one of the scientific applications that is well-suited to parallel computations. At the Superconducting Super Collider, it has been theoretically and empirically demonstrated that particle tracking on a designed lattice can achieve very high parallel efficiency on a MIMD Intel iPSC/860 machine. The key to such success is the realization that the particles can be tracked independently without considering their interaction. The perfectly parallel nature of particle tracking is broken if the interaction effects between particles are included. The space charge introduces an electromagnetic force that will affect the motion of tracked particles in 3-D space. For accurate modeling of the beam dynamics with space charge effects, one needs to solve three-dimensional Maxwell field equations, usually by a particle-in-cell (PIC) algorithm. This will require each particle to communicate with its neighbor grids to compute the momentum changes at each time step. It is expected that the 3-D PIC method will degrade parallel efficiency of particle-tracking implementation on any parallel computer. In this paper, we describe an efficient scheme for implementing particle tracking with space charge effects on an INTEL iPSC/860 machine. Experimental results show that a parallel efficiency of 75% can be obtained

  13. A parallel implementation of particle tracking with space charge effects on an INTEL iPSC/860

    International Nuclear Information System (INIS)

    Particle-tracking simulation is one of the scientific applications that is well-suited to parallel computations. At the Superconducting Super Collider, it has been theoretically and empirically demonstrated that particle tracking on a designed lattice can achieve very high parallel efficiency on a MIMD Intel iPSC/860 machine. The key to such success is the realization that the particles can be tracked independently without considering their interaction. The perfectly parallel nature of particle tracking is broken if the interaction effects between particles are included. The space charge introduces an electromagnetic force that will affect the motion of tracked particles in 3-D space. For accurate modeling of the beam dynamics with space charge effects, one needs to solve three-dimensional Maxwell field equations, usually by a particle-in-cell (PIC) algorithm. This will require each particle to communicate with its neighbor grids to compute the momentum changes at each time step. It is expected that the 3-D PIC method will degrade parallel efficiency of particle-tracking implementation on any parallel computer. In this paper, we describe an efficient scheme for implementing particle tracking with space charge effects on an INTEL iPSC/860 machine. Experimental results show that a parallel efficiency of 75% can be obtained

  14. An algorithm for unfolding neutron dose and dose equivalent from digitized recoil-particle tracks

    International Nuclear Information System (INIS)

    Previous work conducted at the Oak Ridge National Laboratory (ORNL) has demonstrated the feasibility of a digital approach to neutron dosimetry. In contrast to current analog methods, the digital approach specifically refers to methods of collection and processing of ionization products created by recoil particles within detector volumes. A dosimeter utilizing the digital approach would consist of both a detector and a computer algorithm. The detector would measure the integral number of subexcitation electrons produced by recoil particles within various subvolumes of its sensitive volume. The computer algorithm would unfold the quantities absorbed dose, linear energy transfer, and dose equivalent given that digital track-structure information. ORNL researchers have completed a Monte Carlo simulation code of one detector design utilizing the operating principles of time-projection chambers. This thesis presents and verifies one version of the dosimeter's computer algorithm. This algorithm processes the output of the ORNL simulation code, but is applicable to all detectors capable of digitizing recoil-particle tracks. Key features include direct measurement of track lengths and identification of particle type for each registered event. The resulting dosimeter should allow more accurate determinations of neutron dose and dose equivalent compared with conventional dosimeters, which cannot measure these quantities directly. Verification of the algorithm was accomplished by running a variety of recoil particles through the simulated detector volume and comparing the resulting absorbed dose and dose equivalent to those unfolded by the algorithm

  15. The restricted linear energy transfer as a statistical parameter of the particle track structure in radiobiophysics

    International Nuclear Information System (INIS)

    The quantitative aspect of biological radiation effects, as for example the survival probability of a cell, or the average number of chromosome aberrations per cell, depends not only on the radiation dose, but also on the 'radiation quality', i.e. the type of ionizing particles involved and their energy spectrum. Microdosimetry shows that the impact of the radiation quality is a function of the particle track structure, i.e. the mutual positional relationships between ionization processes and excitations along the track of the ionizing particle and its secondary particles. The work in hand therefore was to identify a simple physical parameter of the particle track structure which would represent sufficiently accurately the neighbourhood relationships between the radiation-induced, molecular primary lesions, so as to be suitable for use as a numerical value indicating the radiation quality for the purposes of radiotherapy and radiation protection. The task was to obtain results further supporting the usefulness of this parameter, the restricted LET, and improving its acceptance. (orig./VHE)

  16. An algorithm for unfolding neutron dose and dose equivalent from digitized recoil-particle tracks

    International Nuclear Information System (INIS)

    Previous work had demonstrated the feasibility of a digital approach to neutron dosimetry. A Monte Carlo simulation code of one detector design utilizing the operating principles of time-projection chambers was completed. This thesis presents and verifies one version of the dosimeter's computer algorithm. This algorithm processes the output of the ORNL simulation code, but is applicable to all detectors capable of digitizing recoil-particle tracks. Key features include direct measurement of track lengths and identification of particle type for each registered event. The resulting dosimeter should allow more accurate determinations of neutron dose and dose equivalent compared with conventional dosimeters, which cannot measure these quantities directly. Verification of the algorithm was accomplished by running a variety of recoil particles through the simulated detector volume and comparing the resulting absorbed dose and dose equivalent to those unfolded by the algorithm

  17. Method based on the double sideband technique for the dynamic tracking of micrometric particles

    Science.gov (United States)

    Ramirez, Claudio; Lizana, Angel; Iemmi, Claudio; Campos, Juan

    2016-06-01

    Digital holography (DH) methods are of interest in a large number of applications. Recently, the double sideband (DSB) technique was proposed, which is a DH based method that, by using double filtering, provides reconstructed images without distortions and is free of twin images by using an in-line configuration. In this work, we implement a method for the investigation of the mobility of particles based on the DSB technique. Particle holographic images obtained using the DSB method are processed with digital picture recognition methods, allowing us to accurately track the spatial position of particles. The dynamic nature of the method is achieved experimentally by using a spatial light modulator. The suitability of the proposed tracking method is validated by determining the trajectory and velocity described by glass microspheres in movement.

  18. An application of 222Rn alpha particle's tracks to uranium exploration

    International Nuclear Information System (INIS)

    The uranium exploration method is based on the register of 222Rn alpha particles; 222Rn gas is generated in the chain 238U desintegration. The detection of alpha particles was performed with cellulose nitrate films (NTC), located in a grid at the region in study. The alpha particles produce latent tracks in the NTC films; these tracks may be enlarged by chemical etching and are observed with an ordinary optic microscope, ninety seven NTC films were used, these were distributed in an area of approximately seventeen square kilometers, located in the municipalities of Granados and Huasabas in Sonora Mexico, the detectors remain in the ground for a thirty days mean period. The results obtained show an area with high 222Rn concentration, this can be related with an underground uranium ore deposit. The more important conclusion is that the results obtained in this work can be used as preliminary results for other prospection methods in this particular area. (author)

  19. Software manual for operating particle displacement tracking data acquisition and reduction system

    Science.gov (United States)

    Wernet, Mark P.

    1991-01-01

    The software manual is presented. The necessary steps required to record, analyze, and reduce Particle Image Velocimetry (PIV) data using the Particle Displacement Tracking (PDT) technique are described. The new PDT system is an all electronic technique employing a CCD video camera and a large memory buffer frame-grabber board to record low velocity (less than or equal to 20 cm/s) flows. Using a simple encoding scheme, a time sequence of single exposure images are time coded into a single image and then processed to track particle displacements and determine 2-D velocity vectors. All the PDT data acquisition, analysis, and data reduction software is written to run on an 80386 PC.

  20. Development of two-dimensional velocity field measurement using particle tracking velocimetry on neutron radiography

    International Nuclear Information System (INIS)

    The structures of liquid metal two-phase flow are investigated for analyzing the core meltdown accident of fast reactor. The experiments of high-density ratio two-phase flow for lead-bismuth molten metal and nitrogen gases are conducted to understand in detail. The liquid phase velocity distributions of lead-bismuth molten metal are measured by neutron radiography using Au-Cd tracer particles. The liquid phase velocity distributions are obtained usually by using particle image velocimetry (PIV) on the neutron radiography. The PIV, however is difficult to get the velocity vector distribution quantitatively. An image of neutron radiography is divided into two images of the bubbles and the tracer particles each in particle tracking velocimetry (PTV), which distinguishes tracer contents in the bubble from them in the liquid phase. The locations of tracer particles in the liquid phase are possible to determine by particle mask correlation method, in which the bubble images are separated from the tracer images by Σ-scaling method. The particle tracking velocimetry give a full detail of the velocity vector distributions of the liquid phase in two-phase flow, in comparison with the PIV method. (M. Suetake)

  1. Etching characteristic studies for the detection of alpha particles in DAM–ADC nuclear track detector

    International Nuclear Information System (INIS)

    This study reports the characteristic studies for the detection of alpha particles in DAM–ADC nuclear track detector. Several important parameters that control the track formation such as, the bulk etch rate (VB), track etching rate (VT), dependence of VB and VT on etching concentration and temperature have been extensively studied. The activation energy (Eb) of the bulk etching rate for the DAM–ADC sheets has been calculated, the dependence of etching efficiency and sensitivity upon etchant concentrations and temperature has been investigated, registration efficiency of DAM–ADC detector etched at the optimum etching condition has been examined. The detailed studied results presented in this study provide various useful information about the mechanism of track formation in polymers. - Highlights: • Detection of alpha particles in DAM–ADC nuclear track detector. • The activation energy of the bulk etching rate for the DAM–ADC sheets. • The dependence of etching efficiency upon etchant concentrations • Registration efficiency of DAM–ADC detector

  2. Particle tracking in kaon electroproduction with cathode-charge sampling in multi-wire proportional chambers

    Energy Technology Data Exchange (ETDEWEB)

    Achenbach, P., E-mail: patrick@kph.uni-mainz.de [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany); Ayerbe Gayoso, C.; Bernauer, J.C.; Boehm, R. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany); Bosnar, D. [Department of Physics, University of Zagreb (Croatia); Boesz, M. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany); Debenjak, L. [University of Ljubljana and Jozef Stefan Institute, Ljubljana (Slovenia); Distler, M.O.; Esser, A. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany); Friscic, I. [Department of Physics, University of Zagreb (Croatia); Gomez Rodriguez de la Paz, M. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany); Makek, M. [Department of Physics, University of Zagreb (Croatia); Merkel, H.; Mueller, U.; Nungesser, L.; Pochodzalla, J. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany); Potokar, M. [University of Ljubljana and Jozef Stefan Institute, Ljubljana (Slovenia); Sanchez Majos, S.; Schlimme, B.S. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany); Sirca, S. [University of Ljubljana and Jozef Stefan Institute, Ljubljana (Slovenia)

    2011-06-11

    Wire chambers are routinely operated as tracking detectors in magnetic spectrometers at high-intensity continuous electron beams. Especially in experiments studying reactions with small cross-sections the reaction yield is limited by the background rate in the chambers. One way to determine the track of a charged particle through a multi-wire proportional chamber (MWPC) is the measurement of the charge distribution induced on its cathodes. In practical applications of this read-out method, the algorithm to relate the measured charge distribution to the avalanche position is an important factor for the achievable position resolution and for the track reconstruction efficiency. An algorithm was developed for operating two large-sized MWPCs in a strong background environment with multiple-particle tracks. Resulting efficiencies were determined as a function of the electron beam current and on the signal amplitudes. Because of the different energy-losses of pions, kaons, and protons in the momentum range of the spectrometer the efficiencies depend also on the particle species.

  3. Results of solid state nuclear track detector technique application in radon detection, by alpha particles tracks, for uranium prospecting in Caetite (BA-Brazil)

    International Nuclear Information System (INIS)

    The solid state nuclear track detector technique has been used in radon detection, by alpha particles tracks for uranium prospecting on the ground in Caetite city (Bahia-Brazil). The sensitive film to alpha particles used were CA 8015 exposed during 15 days and the results of three anomalies of this region are showed in a form of maps, made with the density of tracks obtained, and were compared with scintillation counter measurements. The technique showed to be simple and an effective auxiliary for the prospection of uranium ore bodies. The initial uranium exploration costs can be reduced by using this technique. (author)

  4. Text Mining: (Asynchronous Sequences

    Directory of Open Access Journals (Sweden)

    Sheema Khan

    2014-12-01

    Full Text Available In this paper we tried to correlate text sequences those provides common topics for semantic clues. We propose a two step method for asynchronous text mining. Step one check for the common topics in the sequences and isolates these with their timestamps. Step two takes the topic and tries to give the timestamp of the text document. After multiple repetitions of step two, we could give optimum result.

  5. Asynchronous Multiparty Computation

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Geisler, Martin; Krøigaard, Mikkel;

    2009-01-01

    We propose an asynchronous protocol for general multiparty computation. The protocol has perfect security and communication complexity  where n is the number of parties, |C| is the size of the arithmetic circuit being computed, and k is the size of elements in the underlying field. The protocol...... multithreading. Benchmarking of a VIFF implementation of our protocol confirms that it is applicable to practical non-trivial secure computations....

  6. Asynchronous Variational Integrators

    OpenAIRE

    Lew, A.; Marsden, J. E.; Ortiz, M.; West, M

    2003-01-01

    We describe a new class of asynchronous variational integrators (AVI) for nonlinear elastodynamics. The AVIs are distinguished by the following attributes: (i) The algorithms permit the selection of independent time steps in each element, and the local time steps need not bear an integral relation to each other; (ii) the algorithms derive from a spacetime form of a discrete version of Hamilton’s variational principle. As a consequence of this variational structure, the algorith...

  7. Surrogate-driven deformable motion model for organ motion tracking in particle radiation therapy

    International Nuclear Information System (INIS)

    The aim of this study is the development and experimental testing of a tumor tracking method for particle radiation therapy, providing the daily respiratory dynamics of the patient’s thoraco-abdominal anatomy as a function of an external surface surrogate combined with an a priori motion model. The proposed tracking approach is based on a patient-specific breathing motion model, estimated from the four-dimensional (4D) planning computed tomography (CT) through deformable image registration. The model is adapted to the interfraction baseline variations in the patient’s anatomical configuration. The driving amplitude and phase parameters are obtained intrafractionally from a respiratory surrogate signal derived from the external surface displacement. The developed technique was assessed on a dataset of seven lung cancer patients, who underwent two repeated 4D CT scans. The first 4D CT was used to build the respiratory motion model, which was tested on the second scan. The geometric accuracy in localizing lung lesions, mediated over all breathing phases, ranged between 0.6 and 1.7 mm across all patients. Errors in tracking the surrounding organs at risk, such as lungs, trachea and esophagus, were lower than 1.3 mm on average. The median absolute variation in water equivalent path length (WEL) within the target volume did not exceed 1.9 mm-WEL for simulated particle beams. A significant improvement was achieved compared with error compensation based on standard rigid alignment. The present work can be regarded as a feasibility study for the potential extension of tumor tracking techniques in particle treatments. Differently from current tracking methods applied in conventional radiotherapy, the proposed approach allows for the dynamic localization of all anatomical structures scanned in the planning CT, thus providing complete information on density and WEL variations required for particle beam range adaptation. (paper)

  8. A three dimensional method to reconstruct the charged particle tracks in the forward spectrometer

    International Nuclear Information System (INIS)

    A new three dimensional constrained method to reconstruct the charged particle tracks for the forward spectrometers is introduced. Using the method of least squares to solve the equation, the parameters of the tracks can be obtained. In order to reduce the computing time, the two-dimensional x-line is used as the starting points. The authors generated some Monte-Carlo data and compare the results with the data by different methods. It is shown that this method has good resolution and accuracy

  9. The use of conformally-invariant equations to describe tracks of charged particles

    International Nuclear Information System (INIS)

    To calculate tracks of charges particles in electric and magnetic fields, when they are doubly-measured, we have offered a method based on the application of new conformally-invariant variables. These variables are selected in such a way that they simplify the solution of the boundary problem for potentials. We have arrived at the relativistic conformally-invariant equations for tracks in the conic deflecting systems. We also suggest the results of numerical integration of the equations for the simple system with two electrodes. (orig.)

  10. The use of conformally-invariant equations to describe tracks of charged particles

    Energy Technology Data Exchange (ETDEWEB)

    Spivak-Lavrov, I.F. [Pedagogical Inst. of Aktyubinsk (Kazakhstan)

    1995-09-01

    To calculate tracks of charges particles in electric and magnetic fields, when they are doubly-measured, we have offered a method based on the application of new conformally-invariant variables. These variables are selected in such a way that they simplify the solution of the boundary problem for potentials. We have arrived at the relativistic conformally-invariant equations for tracks in the conic deflecting systems. We also suggest the results of numerical integration of the equations for the simple system with two electrodes. (orig.).

  11. Improved estimation of anomalous diffusion exponents in single particle tracking experiments

    CERN Document Server

    Bronshtein, Eldad Kepten Irena

    2013-01-01

    The Mean Square Displacement is a central tool in the analysis of Single Particle Tracking experiments, shedding light on various biophysical phenomena. Frequently, parameters are extracted by performing time-averages on single particle trajectories followed by ensemble averaging. This procedure however, suffers from two systematic errors when applied to particles that perform anomalous diffusion. The first is significant at short time lags and is induced by measurement errors. The second arises from the natural heterogeneity in biophysical systems. We show how to estimate and correct these two errors and improve the estimation of the anomalous parameters for the whole particle distribution. As a consequence we manage to characterize ensembles of heterogeneous particles even for rather short and noisy measurements where regular time averaged mean square displacement analysis fails. We apply this method to both simulations and in vivo measurements of telomere diffusion in 3T3 mouse embryonic fibroblast cells. ...

  12. Three-dimensional tracking of acoustophoretic particle trajectories in a Poiseuille flow

    Science.gov (United States)

    Barnkob, Rune; Rossi, Massimiliano; Marin, Alvaro G.; Kähler, Christian J.

    2013-11-01

    Acoustics in microfluidics has proved as an excellent technique for particle separation. The technique is often based on advecting the particles by a Poiseuille flow, while acoustic forces push the particles transversely across the flow according to particle size, density, and compressibility. In this work we study such particle trajectories in a microchannel containing a dilute particle suspension. The microchannel is excited in its transverse ultrasound half-wave resonance, while a Poiseuille flow is imposed along the channel. In addition to the viscous drag force from the imposed flow, the particles are subject to forces from acoustic radiation as well as viscous drag from acoustic streaming (Muller et al., PRE, in press, 2013). In the microchannel cross-section, the acoustic streaming is two-dimensional, while the acoustic radiation force is one-dimensional. However, the actual particle velocity induced by the acoustic radiation force has a two-dimensional character due to wall-enhancement of the viscous Stokes drag. In the experiments, we use a 3D astigmatic particle tracking technique (APTV, Cierpka et al., Meas Sci Technol 22, 2011) to determine the particle trajectories, which we compare to theoretical predictions for future optimization of acoustic separation systems. DFG, grant no. KA 1808/16-1.

  13. Real-Time MRI-Guided Catheter Tracking Using Hyperpolarized Silicon Particles

    Science.gov (United States)

    Whiting, Nicholas; Hu, Jingzhe; Shah, Jay V.; Cassidy, Maja C.; Cressman, Erik; Zacharias Millward, Niki; Menter, David G.; Marcus, Charles M.; Bhattacharya, Pratip K.

    2015-08-01

    Visualizing the movement of angiocatheters during endovascular interventions is typically accomplished using x-ray fluoroscopy. There are many potential advantages to developing magnetic resonance imaging-based approaches that will allow three-dimensional imaging of the tissue/vasculature interface while monitoring other physiologically-relevant criteria, without exposing the patient or clinician team to ionizing radiation. Here we introduce a proof-of-concept development of a magnetic resonance imaging-guided catheter tracking method that utilizes hyperpolarized silicon particles. The increased signal of the silicon particles is generated via low-temperature, solid-state dynamic nuclear polarization, and the particles retain their enhanced signal for ≥40 minutes—allowing imaging experiments over extended time durations. The particles are affixed to the tip of standard medical-grade catheters and are used to track passage under set distal and temporal points in phantoms and live mouse models. With continued development, this method has the potential to supplement x-ray fluoroscopy and other MRI-guided catheter tracking methods as a zero-background, positive contrast agent that does not require ionizing radiation.

  14. Asynchronous Bounded Expected Delay Networks

    OpenAIRE

    Bakhshi, Rena; Endrullis, Jörg; Fokkink, Wan; Pang, Jun

    2010-01-01

    The commonly used asynchronous bounded delay (ABD) network models assume a fixed bound on message delay. We propose a probabilistic network model, called asynchronous bounded expected delay (ABE) model. Instead of a strict bound, the ABE model requires only a bound on the expected message delay. While the conditions of ABD networks restrict the set of possible executions, in ABE networks all asynchronous executions are possible, but executions with extremely long delays are less probable. In ...

  15. Parallel computing of a digital hologram and particle searching for microdigital-holographic particle-tracking velocimetry

    International Nuclear Information System (INIS)

    We have developed a parallel algorithm for microdigital-holographic particle-tracking velocimetry. The algorithm is used in (1) numerical reconstruction of a particle image computer using a digital hologram, and (2) searching for particles. The numerical reconstruction from the digital hologram makes use of the Fresnel diffraction equation and the FFT (fast Fourier transform),whereas the particle search algorithm looks for local maximum graduation in a reconstruction field represented by a 3D matrix. To achieve high performance computing for both calculations (reconstruction and particle search), two memory partitions are allocated to the 3D matrix. In this matrix, the reconstruction part consists of horizontally placed 2D memory partitions on the x-y plane for the FFT, whereas, the particle search part consists of vertically placed 2D memory partitions set along the z axes.Consequently, the scalability can be obtained for the proportion of processor elements,where the benchmarks are carried out for parallel computation by a SGI Altix machine

  16. Magnetic poly(lactide-co-glycolide) and cellulose particles for MRI-based cell tracking.

    Science.gov (United States)

    Nkansah, Michael K; Thakral, Durga; Shapiro, Erik M

    2011-06-01

    Biodegradable, superparamagnetic microparticles and nanoparticles of poly(lactide-co-glycolide) (PLGA) and cellulose were designed, fabricated, and characterized for magnetic cell labeling. Monodisperse nanocrystals of magnetite were incorporated into microparticles and nanoparticles of PLGA and cellulose with high efficiency using an oil-in-water single emulsion technique. Superparamagnetic cores had high magnetization (72.1 emu/g). The resulting polymeric particles had smooth surface morphology and high magnetite content (43.3 wt % for PLGA and 69.6 wt % for cellulose). While PLGA and cellulose nanoparticles displayed highest r 2* values per millimole of iron (399 sec(-1) mM(-1) for cellulose and 505 sec(-1) mM(-1) for PLGA), micron-sized PLGA particles had a much higher r 2* per particle than either. After incubation for a month in citrate buffer (pH 5.5), magnetic PLGA particles lost close to 50% of their initial r 2* molar relaxivity, while magnetic cellulose particles remained intact, preserving over 85% of their initial r 2* molar relaxivity. Lastly, mesenchymal stem cells and human breast adenocarcinoma cells were magnetically labeled using these particles with no detectable cytotoxicity. These particles are ideally suited for noninvasive cell tracking in vivo via MRI and due to their vastly different degradation properties, offer unique potential for dedicated use for either short (PLGA-based particles) or long-term (cellulose-based particles) experiments. PMID:21404328

  17. Particle track densities in double drive tube 60009/10. [in plagioclase of lunar soil samples

    Science.gov (United States)

    Blanford, G. E.; Wood, G. C.; Mckay, D. S.

    1977-01-01

    Measurements are reported of particle track densities in grains from a suite of eleven samples from the Apollo 16 double drive tube 60009/10. All of the samples studied in 60009 show a clearly bimodal distribution of track densities in plagioclase. This bimodal distribution is interpreted to indicate a mixing of a relatively immature soil with a relatively mature soil. This mixing was not followed by any appreciable reworking which would have altered the distribution. The three lower samples in 60010 also show a bimodal distribution. However, the three uppermost samples show a unimodal distribution. The percentage of high track density plagioclase grains shows a good correlation with the other maturity indices of agglutinate content and the ferromagnetic resonance intensity.

  18. Beam test of a 12-layer scintillating-fiber charged-particle tracking system

    International Nuclear Information System (INIS)

    A 96-channel, 3-superlayer, scintillating-fiber tracking system has been tested in a 5 GeV/c π- beam. The scintillating fibers were 830 μm in diameter, spaced 850 μm apart, and 4.3 m in length. They were coupled to 6 m long, clear fiber waveguides and finally to visible light photon counters. A spatial resolution of ∼150 μm for a double-layered ribbon was achieved with this tracking system. This first prototype of a charged-particle tracking system configured for the Solenoidal Detector Collaboration at the Superconducting Super Collider is a benchmark in verifying the expected number of photoelectrons from the fibers. (orig.)

  19. Modeling Bimolecular Reactions and Transport in Porous Media Via Particle Tracking

    Energy Technology Data Exchange (ETDEWEB)

    Dong Ding; David Benson; Amir Paster; Diogo Bolster

    2012-01-01

    We use a particle-tracking method to simulate several one-dimensional bimolecular reactive transport experiments. In this numerical method, the reactants are represented by particles: advection and dispersion dominate the flow, and molecular diffusion dictates, in large part, the reactions. The particle/particle reactions are determined by a combination of two probabilities dictated by the physics of transport and energetics of reaction. The first is that reactant particles occupy the same volume over a short time interval. The second is the conditional probability that two collocated particles favorably transform into a reaction. The first probability is a direct physical representation of the degree of mixing in an advancing displacement front, and as such lacks empirical parameters except for the user-defined number of particles. This number can be determined analytically from concentration autocovariance, if this type of data is available. The simulations compare favorably to two physical experiments. In one, the concentration of product, 1,2-naphthoquinoe-4-aminobenzene (NQAB) from reaction between 1,2-naphthoquinone-4-sulfonic acid (NQS) and aniline (AN), was measured at the outflow of a column filled with glass beads at different times. In the other, the concentration distribution of reactants (CuSO_4 and EDTA^{4-}) and products (CuEDTA^{4-}) were quantified by snapshots of transmitted light through a column packed with cryloite sand. The thermodynamic rate coefficient in the latter experiment was 10^7 times greater than the former experiment, making it essentially instantaneous. When compared to the solution of the advection-dispersion-reaction equation (ADRE) with the well-mixed reaction coefficient, the experiments and the particle-tracking simulations showed on the order of 20% to 40% less overall product, which is attributed to poor mixing. The poor mixing also leads to higher product concentrations on the edges of the mixing zones, which the particle

  20. A parallel implementation of particle tracking with space charge effects on an Intel iPSC/860

    International Nuclear Information System (INIS)

    Particle-tracking simulation is one of the scientific applications that is well-suited to parallel computations. At the Superconducting Super Collider, it has been theoretically and empirically demonstrated that particle tracking on a designed lattice can achieve very high parallel efficiency on a MIMD Intel iPSC/860 macene. The key to such success is the realization that the particles can be tracked independently without considering their interaction. The perfectly parallel nature of particle tracking is broken if the interaction effects between particles are included. The space charge introduces an electromagnetic force that will affect the motion of tracked particles in 3-D space. For accurate modeling of the beam dynamics with space charge effects, one needs to solve three-dimensional Maxwell field equations, usually by a particle-in-cell (PIC) algorithm. This will require each particle to communicate with its neighbor grids to compute the momentum changes at each time step. It is expected that the 3-D PIC method will degrade parallel computer. In this paper, we describe an efficient scheme for implementing particle tracking with space charge effects on an INTEL iPSC/860 machine. Experimental results show that a parallel efficiency of 75% can be obtained

  1. Two dimensional, electronic particle tracking in liquids with a graphene-based magnetic sensor array

    Science.gov (United States)

    Neumann, Rodrigo F.; Engel, Michael; Steiner, Mathias

    2016-07-01

    The investigation and control of liquid flow at the nanometer scale is a key area of applied research with high relevance to physics, chemistry, and biology. We introduce a method and a device that allows the spatial resolution of liquid flow by integrating an array of graphene-based magnetic (Hall) sensors that is used for tracking the movement of magnetic nanoparticles immersed in a liquid under investigation. With a novel device concept based on standard integration processes and experimentally verified material parameters, we numerically simulate the performance of a single sensor pixel, as well as the whole sensor array, for tracking magnetic nanoparticles having typical properties. The results demonstrate that the device enables (a) the detection of individual nanoparticles in the liquid with high accuracy and (b) the reconstruction of a particle's flow-driven trajectory across the integrated sensor array with sub-pixel precision as a function of time, in what we call the ``Magnetic nanoparticle velocimetry'' technique. Since the method does not rely on optical detection, potential lab-on-chip applications include particle tracking and flow analysis in opaque media at the sub-micron scale.The investigation and control of liquid flow at the nanometer scale is a key area of applied research with high relevance to physics, chemistry, and biology. We introduce a method and a device that allows the spatial resolution of liquid flow by integrating an array of graphene-based magnetic (Hall) sensors that is used for tracking the movement of magnetic nanoparticles immersed in a liquid under investigation. With a novel device concept based on standard integration processes and experimentally verified material parameters, we numerically simulate the performance of a single sensor pixel, as well as the whole sensor array, for tracking magnetic nanoparticles having typical properties. The results demonstrate that the device enables (a) the detection of individual

  2. Particle Data Management Software for 3DParticle Tracking Velocimetry and Related Applications – The Flowtracks Package

    Directory of Open Access Journals (Sweden)

    Yosef Meller

    2016-06-01

    Full Text Available The Particle Tracking Velocimetry (PTV community employs several formats of particle information such as position and velocity as function of time, i.e. trajectory data, as a result of diverging needs unmet by existing formats, and a number of different, mostly home-grown, codes for handling the data. Flowtracks is a Python package that provides a single code base for accessing different formats as a database, i.e. storing data and programmatically manipulating them using format-agnostic data structures. Furthermore, it offers an HDF5-based format that is fast and extensible, obviating the need for other formats. The package may be obtained from https://github.com/OpenPTV/postptv and used as-is by many fluid-dynamics labs, or with minor extensions adhering to a common interface, by researchers from other fields, such as biology and population tracking.

  3. Thermoluminescence and nuclear particle tracks in ALHA-81005 Evidence for a brief transit time

    Science.gov (United States)

    Sutton, S. R.; Crozaz, G.

    1983-09-01

    Thermoluminescence and nuclear particle track measurements were made on the Antarctic meteorite ALHA-81005. No nuclear particle tracks were found in lithic fragments indicating that the clast material never resided at the very surface of the parent body. The unusually low natural thermoluminescence of this material is interpreted as being due to a combination of anomalous fading and thermal decay. The thermal decay could be due to very long terrestrial age or heating either during atmospheric entry, in a near sun orbit or during a parent body impact event. Impact heating is considered the more likely of these possibilities for this meteorite. If the impact heating interpretation is correct the thermoluminescence data constrains the space exposure time of the object to be less than 2,500 years. Such a brief earth transit time is consistent with a lunar origin for this meteorite.

  4. Application of nuclear particle tracks: A scanning x-ray microscope

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, P.J.

    1991-09-30

    The scanning x-ray microscope (SXM) is a short-wavelength analog of a near-field optical-scanning microscope, promising spatial resolution of {approximately}100{angstrom} up to {approximately}5 keV x-ray energy. A portion of a synchrotron x-ray beam streams through an etched nuclear particle track in an opaque membrane and impinges on an object within the narrow stream. Scattered or transmitted x-rays are detected with a photon counter. The SXM is feasible because a useful number of synchrotron x-rays, even from a bend magnet, will stream through a small diameter pore. The properties and limitations of the SXM are discussed together with other submicroscopic applications of nuclear particle tracks. 14 refs., 8 figs., 1 tab.

  5. 3D Head Pose Tracking Using a Particle Filter with Nose Template Matching

    Science.gov (United States)

    Kubota, Hitoshi; Takeshi, Masami; Saito, Hideo

    In this paper, we propose a real-time tracking method for driver's head pose in real vehicle environment by using multiple NIR cameras. In order to achieve real-time performance and high-accuracy, 6-DOF of head pose is estimated by a particle filter with restricted state space. Firstly, the 3D position of nose hole is measured by template matching of stereo images. Because nose hole is the most dark area in the captured NIR images, we can robustly detect the position of the nose very precisely. From the 3D position of the nose, we can estimate the head pose as an initial estimate. Then, each hypothesis is updated by prior probability with a constraint of nose position. Thus it can reduce the number of particles with maintained accuracy. The experimental results indicate that this method is effective for head pose tracking.

  6. Single-sheet identification method of heavy charged particles using solid state nuclear track detectors

    Indian Academy of Sciences (India)

    M F Zaki; A Abdel-Naby; A Ahmed Morsy

    2007-08-01

    The theoretical and experimental investigations of the penetration of charged particles in matter played a very important role in the development of modern physics. Solid state nuclear track detectors have become one of the most important tools for many branches of science and technology. An attempt has been made to examine the suitability of the single-sheet particle identification technique in CR-39 and CN-85 polycarbonate by plotting track cone length vs. residual range for different heavy ions in these detectors. So, the maximum etchable ranges of heavy ions such as 93Nb, 86Kr and 4He in CR-39 and 4He and 132Xe in CN-85 polycarbonate have been determined. The ranges of these ions in these detectors have also been computed theoretically using the Henke–Benton program. A reasonably good agreement has been observed between the experimentally and theoretically computed values.

  7. Innovative molecular-based fluorescent nanoparticles for multicolor single particle tracking in cells

    Science.gov (United States)

    Daniel, Jonathan; Godin, Antoine G.; Palayret, Matthieu; Lounis, Brahim; Cognet, Laurent; Blanchard-Desce, Mireille

    2016-03-01

    Based on an original molecular-based design, we present bright and photostable fluorescent organic nanoparticles (FONs) showing excellent colloidal stability in various aqueous environments. Complementary near-infrared emitting and green emitting FONs were prepared using a simple, fast and robust protocol. Both types of FONs could be simultaneously imaged at the single-particle level in solution as well as in biological environments using a monochromatic excitation and a dual-color fluorescence microscope. No evidence of acute cytotoxicity was found upon incubation of live cells with mixed solutions of FONs, and both types of nanoparticles were found internalized in the cells where their motion could be simultaneously tracked at video-rate up to minutes. These fluorescent organic nanoparticles open a novel non-toxic alternative to existing nanoparticles for imaging biological structures, compatible with live-cell experiments and specially fitted for multicolor single particle tracking.

  8. Passive Target Tracking in Non-cooperative Radar System Based on Particle Filtering

    Institute of Scientific and Technical Information of China (English)

    LI Shuo; TAO Ran

    2006-01-01

    We propose a target tracking method based on particle filtering(PF) to solve the nonlinear non-Gaussian target-tracking problem in the bistatic radar systems using external radiation sources. Traditional nonlinear state estimation method is extended Kalman filtering (EKF), which is to do the first level Taylor series extension. It will cause an inaccuracy or even a scatter estimation result on condition that there is either a highly nonlinear target or a large noise square-error. Besides, Kalman filtering is the optimal resolution under a Gaussian noise assumption, and is not suitable to the non-Gaussian condition. PF is a sort of statistic filtering based on Monte Carlo simulation that is using some random samples (particles) to simulate the posterior probability density of system random variables. This method can be used in any nonlinear random system. It can be concluded through simulation that PF can achieve higher accuracy than the traditional EKF.

  9. Preparation of Scandium-46 glass microspheres for application in radioactive particle tracking experiments

    International Nuclear Information System (INIS)

    This paper describes a novel approach for preparation of scandium oxide-glass microspheres for use as radiotracer in radioactive particle tracking (RPT) experiments conducted for flow visualization in industrial systems. The approach involves preparation of scandium (1 % Sc2O3) glass, crushing the glass into small particles of different sizes, converting the non-spherical particles into spherical particles using an indigenously developed novel approach. The obtained spherical glass microspheres were irradiated with thermal neutrons in a nuclear reactor and the activity of Scandium-46 was measured. The activity of the scandium glass microsphere of size 500-1500 μm was found to be 40-325 μCi. (author)

  10. Preparation and quantification of radioactive particles for tracking hydrodynamic behavior in multiphase reactors.

    Science.gov (United States)

    Yunos, Mohd Amirul Syafiq Mohd; Hussain, Siti Aslina; Yusoff, Hamdan Mohamed; Abdullah, Jaafar

    2014-09-01

    Radioactive particle tracking (RPT) has emerged as a promising and versatile technique that can provide rich information about a variety of multiphase flow systems. However, RPT is not an off-the-shelf technique, and thus, users must customize RPT for their applications. This paper presents a simple procedure for preparing radioactive tracer particles created via irradiation with neutrons from the TRIGA Mark II research reactor. The present study focuses on the performance evaluation of encapsulated gold and scandium particles for applications as individual radioactive tracer particles using qualitative and quantitative neutron activation analysis (NAA) and an X-ray microcomputed tomography (X-ray Micro-CT) scanner installed at the Malaysian Nuclear Agency. PMID:24907683

  11. Multi-view body tracking with a detector-driven hierarchical particle filter

    OpenAIRE

    Navarro, S.; López Méndez, Adolfo; Alcoverro Vidal, Marcel; Casas Pla, Josep Ramon

    2012-01-01

    In this paper we present a novel approach to markerless human motion capture that robustly integrates body part detections in multiple views. The proposed method fuses cues from multiple views to enhance the propagation and observation model of particle filtering methods aiming at human motion capture. We particularize our method to improve arm tracking in the publicly available IXMAS dataset. Our experiments show that the proposed method outperforms other state-ofthe- ar...

  12. WLAN-Based Pedestrian Tracking Using Particle Filters and Low-Cost MEMS Sensors

    OpenAIRE

    Wang, Hui; Lenz, Henning; Szabo, Andrei; Bamberger, Joachim; Hanebeck, Uwe D.

    2007-01-01

    Indoor positioning systems based on Wireless LAN (WLAN) are being widely investigated in academia and industry. Meanwhile, the emerging low-cost MEMS sensors can also be used as another independent positioning source. In this paper, we propose a pedestrian tracking framework based on particle filters, which extends the typical WLAN-based indoor positioning systems by integrating low-cost MEMS accelerometer and map information. Our simulation and real world experiments indicate a remarkable pe...

  13. Adaptation of multidimensional group particle tracking and particle wall-boundary condition model to the FDNS code

    Science.gov (United States)

    Chen, Y. S.; Farmer, R. C.

    1992-01-01

    A particulate two-phase flow CFD model was developed based on the FDNS code which is a pressure based predictor plus multi-corrector Navier-Stokes flow solver. Turbulence models with compressibility correction and the wall function models were employed as submodels. A finite-rate chemistry model was used for reacting flow simulation. For particulate two-phase flow simulations, a Eulerian-Lagrangian solution method using an efficient implicit particle trajectory integration scheme was developed in this study. Effects of particle-gas reaction and particle size change to agglomeration or fragmentation were not considered in this investigation. At the onset of the present study, a two-dimensional version of FDNS which had been modified to treat Lagrangian tracking of particles (FDNS-2DEL) had already been written and was operational. The FDNS-2DEL code was too slow for practical use, mainly because it had not been written in a form amenable to vectorization on the Cray, nor was the full three-dimensional form of FDNS utilized. The specific objective of this study was to reorder to calculations into long single arrays for automatic vectorization on the Cray and to implement the full three-dimensional version of FDNS to produce the FDNS-3DEL code. Since the FDNS-2DEL code was slow, a very limited number of test cases had been run with it. This study was also intended to increase the number of cases simulated to verify and improve, as necessary, the particle tracking methodology coded in FDNS.

  14. Optimization of microchannel plate multipliers for tracking minimum-ionizing particles

    Energy Technology Data Exchange (ETDEWEB)

    Oba, K.; Rehak, P.; Potter, D.

    1981-01-01

    The progress in development of special Microchannel Plates for particle tracking is reported. The requirements of (1) high spatial resolution; (2) high density of information; and (3) rate capability were found to be satisfied in a thick Microchannel Plate with a CsI coating operating in a focusing magnetic field. The measurements of the Microchannel Plate detection efficiency, gain and noise are presented for several detectors. The pictures of the passage and interaction of the high energy charged particles inside the detector are shown.

  15. A new positron emission particle tracking facility at iThemba LABS

    International Nuclear Information System (INIS)

    Positron emission particle tracking (PEPT) has become a powerful tool for in-situ characterisation of particulate flow within aggressive industrial environments, such as tumbling mills and powder mixers. PEPT is based on the tracking of a single tracer particle which has been labelled with a radionuclide that decays via β decay. The location of the particle is obtained by the triangulation of events associated with the detection of pairs of annihilation γ rays in a modified 'positron camera'. One of the challenges facing PEPT is associated with labelling sub-millimetre sized particles which would allow studies in systems of finer particulate flow, such as flotation cells. The Positron Imaging Centre at the University of Birmingham is currently the only operational PEPT facility in the world. We are presently installing a PEPT laboratory at the iThemba LABS cyclotron facility in Cape Town. Details of this new facility will be presented, together with a flavour of recent PEPT data obtained in Birmingham, and results from our accelerator-based studies at iThemba LABS which are aimed at extending the state-of-the-art in the size and type of labelled tracer particles for PEPT work. (author)

  16. Particle Filter with Integrated Voice Activity Detection for Acoustic Source Tracking

    Directory of Open Access Journals (Sweden)

    Anders M. Johansson

    2007-01-01

    Full Text Available In noisy and reverberant environments, the problem of acoustic source localisation and tracking (ASLT using an array of microphones presents a number of challenging difficulties. One of the main issues when considering real-world situations involving human speakers is the temporally discontinuous nature of speech signals: the presence of silence gaps in the speech can easily misguide the tracking algorithm, even in practical environments with low to moderate noise and reverberation levels. A natural extension of currently available sound source tracking algorithms is the integration of a voice activity detection (VAD scheme. We describe a new ASLT algorithm based on a particle filtering (PF approach, where VAD measurements are fused within the statistical framework of the PF implementation. Tracking accuracy results for the proposed method is presented on the basis of synthetic audio samples generated with the image method, whereas performance results obtained with a real-time implementation of the algorithm, and using real audio data recorded in a reverberant room, are published elsewhere. Compared to a previously proposed PF algorithm, the experimental results demonstrate the improved robustness of the method described in this work when tracking sources emitting real-world speech signals, which typically involve significant silence gaps between utterances.

  17. A new dyed ECE track identification method for nuclear particle detection

    International Nuclear Information System (INIS)

    A new procedure for obtaining highly contrasted red-dyed electrochemically etched recoil tracks in polymers such as polycarbonate (PC) and CR-39 has been successfully developed for spectrophotometry as applied to neutron dosimetry. The principal rationale in this method has been the provision of highly contrasted, photon-absorbing, large, dyed recoil tracks in an unaffected bulk material. The method consists of: (a) exposing the polymer to charged particles or neutrons; (b) electrochemical etching of the tracks; (c) acid sensitization; (d) dyeing with an appropriate dye. By investigation of the type, concentration, duration and temperature of the acid and the dye, optimized values of 20% by weight acrylic acid at 750C for 3.5 h for sensitization, and 3% by weight eosin bluish dye at 950C for 4 h for dyeing, provided a nearly 100% dyed-track efficiency. Spectrophotometry by UV and infrared radiation track counting, and optical densitometry were applied to the dyed samples. The results have shown some promise for UV absorbance measurements in routine large-scale applications. In this paper, the results of optimization studies and preliminary application of the technique to neutron dosimetry are presented and discussed. (author)

  18. A computational framework for particle and whole cell tracking applied to a real biological dataset.

    Science.gov (United States)

    Yang, Feng Wei; Venkataraman, Chandrasekhar; Styles, Vanessa; Kuttenberger, Verena; Horn, Elias; von Guttenberg, Zeno; Madzvamuse, Anotida

    2016-05-24

    Cell tracking is becoming increasingly important in cell biology as it provides a valuable tool for analysing experimental data and hence furthering our understanding of dynamic cellular phenomena. The advent of high-throughput, high-resolution microscopy and imaging techniques means that a wealth of large data is routinely generated in many laboratories. Due to the sheer magnitude of the data involved manual tracking is often cumbersome and the development of computer algorithms for automated cell tracking is thus highly desirable. In this work, we describe two approaches for automated cell tracking. Firstly, we consider particle tracking. We propose a few segmentation techniques for the detection of cells migrating in a non-uniform background, centroids of the segmented cells are then calculated and linked from frame to frame via a nearest-neighbour approach. Secondly, we consider the problem of whole cell tracking in which one wishes to reconstruct in time whole cell morphologies. Our approach is based on fitting a mathematical model to the experimental imaging data with the goal being that the physics encoded in the model is reflected in the reconstructed data. The resulting mathematical problem involves the optimal control of a phase-field formulation of a geometric evolution law. Efficient approximation of this challenging optimal control problem is achieved via advanced numerical methods for the solution of semilinear parabolic partial differential equations (PDEs) coupled with parallelisation and adaptive resolution techniques. Along with a detailed description of our algorithms, a number of simulation results are reported on. We focus on illustrating the effectivity of our approaches by applying the algorithms to the tracking of migrating cells in a dataset which reflects many of the challenges typically encountered in microscopy data. PMID:26948574

  19. Network-Based Output Tracking Control for a Class of T-S Fuzzy Systems That Can Not Be Stabilized by Nondelayed Output Feedback Controllers.

    Science.gov (United States)

    Zhang, Dawei; Han, Qing-Long; Jia, Xinchun

    2015-08-01

    This paper investigates network-based output tracking control for a T-S fuzzy system that can not be stabilized by a nondelayed fuzzy static output feedback controller, but can be stabilized by a delayed fuzzy static output feedback controller. By intentionally introducing a communication network that produces proper network-induced delays in the feedback control loop, a stable and satisfactory tracking control can be ensured for the T-S fuzzy system. Due to the presence of network-induced delays, the fuzzy system and the fuzzy tracking controller operate in an asynchronous way. Taking the asynchronous operation and network-induced delays into consideration, the network-based tracking control system is modeled as an asynchronous T-S fuzzy system with an interval time-varying delay. A new delay-dependent criterion for L2 -gain tracking performance is derived by using the deviation bounds of asynchronous normalized membership functions and a complete Lyapunov-Krasovskii functional. Applying a particle swarm optimization technique with the feasibility of the derived criterion, a novel design algorithm is presented to determine the minimum L2 -gain tracking performance and control gains simultaneously. The effectiveness of the proposed method is illustrated by performing network-based output tracking control of a Duffing-Van der Pol's oscillator. PMID:25222965

  20. Analysis of Base-Case Particle Tracking Results of the Base-Case Flow Fields (ID:U0160)

    International Nuclear Information System (INIS)

    The purpose of this analysis is to provide insight into the unsaturated-zone (UZ) subsystem performance through particle tracking analyses of the base-case flow fields. The particle tracking analyses will not be used directly in total-system performance-assessment (TSPA) calculations per se. The objective of this activity is to evaluate the transport of radionuclides through the unsaturated zone and to determine how different system parameters such as matrix diffusion, sorption, water-table rise, and perched water influence the transport to the water table. Plots will be generated to determine normalized cumulative breakthrough curves for selected radionuclides. The scope of this work is limited to the particle tracking analyses of ''base-case'' flow fields that are to be used by the code FEHM (Finite Element Heat and Mass; Zyvoloski 1997) for particle tracking simulations in ''Total System Performance Assessment-Site Recommendation Report'' (TSPA-SR)

  1. Analysis of Base-Case Particle Tracking Results of the Base-Case Flow Fields (ID:U0160)

    Energy Technology Data Exchange (ETDEWEB)

    C.K. Ho

    2000-01-19

    The purpose of this analysis is to provide insight into the unsaturated-zone (UZ) subsystem performance through particle tracking analyses of the base-case flow fields. The particle tracking analyses will not be used directly in total-system performance-assessment (TSPA) calculations per se. The objective of this activity is to evaluate the transport of radionuclides through the unsaturated zone and to determine how different system parameters such as matrix diffusion, sorption, water-table rise, and perched water influence the transport to the water table. Plots will be generated to determine normalized cumulative breakthrough curves for selected radionuclides. The scope of this work is limited to the particle tracking analyses of ''base-case'' flow fields that are to be used by the code FEHM (Finite Element Heat and Mass; Zyvoloski 1997) for particle tracking simulations in ''Total System Performance Assessment-Site Recommendation Report'' (TSPA-SR).

  2. Monte Carlo mesh tallies based on a Kernel Density Estimator approach using integrated particle tracks

    International Nuclear Information System (INIS)

    A new Monte Carlo mesh tally based on a Kernel Density Estimator (KDE) approach using integrated particle tracks is presented. We first derive the KDE integral-track estimator and present a brief overview of its implementation as an alternative to the MCNP fmesh tally. To facilitate a valid quantitative comparison between these two tallies for verification purposes, there are two key issues that must be addressed. The first of these issues involves selecting a good data transfer method to convert the nodal-based KDE results into their cell-averaged equivalents (or vice versa with the cell-averaged MCNP results). The second involves choosing an appropriate resolution of the mesh, since if it is too coarse this can introduce significant errors into the reference MCNP solution. After discussing both of these issues in some detail, we present the results of a convergence analysis that shows the KDE integral-track and MCNP fmesh tallies are indeed capable of producing equivalent results for some simple 3D transport problems. In all cases considered, there was clear convergence from the KDE results to the reference MCNP results as the number of particle histories was increased. (authors)

  3. Modification of thermal, optical and structural properties of bayfol nuclear track detector by alpha particles irradiation

    International Nuclear Information System (INIS)

    The effect of alpha particle dose on the thermal, optical and structural properties of Bayfol solid state nuclear track detector (SSNTD) was investigated. Non-isothermal studies were carried out using thermal gravimetric analysis (TGA) and differential thermal gravimetric (DTG) to obtain the activation energy of decomposition for Bayfol detector. Thermal gravimetric analysis (TGA) indicates that the Bayfol samples decompose in one main break down stage. Samples from 250 cm thickness sheets were exposed to alpha particles in the dose range 3.5-67.03 Gy. The variation of transition temperatures with the alpha particle dose has been determined using differential thermal analysis (DTA). The results indicate that the irradiation with alpha particles in the dose range 26.81-67.03 Gy decreases the melting temperature of the Bayfol samples and this is most suitable for applications requiring the molding of this polymer at lower temperatures. Also, the alpha particle dose gives advantage for increasing the correlation between melting temperatures and the amount of crystalline regions that is related to both cross-linking and degradation phenomena. In addition, optical and structural property studies using refractive index, IR spectroscopy, and x-ray diffraction measurements were performed on non irradiated and irradiated Bayfol samples. The results indicate that the anisotropic character, absorbance and the degree of ordering of the Bayfol polymer are dependent on the alpha particle dose

  4. Interpolating cathode pad readout in gas proportional detectors for high multiplicity particle tracks

    Energy Technology Data Exchange (ETDEWEB)

    Yu, B.; Radeka, V.; Smith, G.C.; O`Brien, E.

    1992-02-01

    Experiments which are planned for the Superconducting Super Collider and the Relativistic Heavy Ion Collider will involve interactions in which detectors will need to identify and localize hundreds or even thousands of particle tracks simultaneously. Most types of conventional position sensitive, proportional detectors with projective geometry are not able to unravel the individual tracks in these environments. We have been investigating several forms of sub-divided cathode readout to address this problem. We report here on geometric charge division using chevron shaped cathode pads which lie in rows underneath each anode wire. Investigations have quantified the non-linear effects due to avalanche angular localization, and how these become negligible with proper design of the pad. Differential nm-linearity of {plus_minus}5%, and position resolution in the region of 50{mu}m rms, have been achieved.

  5. Interpolating cathode pad readout in gas proportional detectors for high multiplicity particle tracks

    Energy Technology Data Exchange (ETDEWEB)

    Yu, B.; Radeka, V.; Smith, G.C.; O' Brien, E.

    1992-02-01

    Experiments which are planned for the Superconducting Super Collider and the Relativistic Heavy Ion Collider will involve interactions in which detectors will need to identify and localize hundreds or even thousands of particle tracks simultaneously. Most types of conventional position sensitive, proportional detectors with projective geometry are not able to unravel the individual tracks in these environments. We have been investigating several forms of sub-divided cathode readout to address this problem. We report here on geometric charge division using chevron shaped cathode pads which lie in rows underneath each anode wire. Investigations have quantified the non-linear effects due to avalanche angular localization, and how these become negligible with proper design of the pad. Differential nm-linearity of {plus minus}5%, and position resolution in the region of 50{mu}m rms, have been achieved.

  6. Direction Tracking of Multiple Moving Targets Using Quantum Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Gao Hongyuan

    2016-01-01

    Full Text Available Based on weighted signal covariance (WSC matrix and maximum likelihood (ML estimation, a directionof-arrival (DOA estimation method of multiple moving targets is designed and named as WSC-ML in the presence of impulse noise. In order to overcome the shortcoming of the multidimensional search cost of maximum likelihood estimation, a novel continuous quantum particle swarm optimization (QPSO is proposed for this continuous optimization problem. And a tracking method of multiple moving targets in impulsive noise environment is proposed and named as QPSO-WSC-ML. Later, we make use of rank-one updating to update the weighted signal covariance matrix of WSC-ML. Simulation results illustrate the proposed QPSO-WSC-ML method is efficient and robust for the direction tracking of multiple moving targets in the presence of impulse noise.

  7. Development of a scintillation-fiber detector for real-time particle tracking

    International Nuclear Information System (INIS)

    The prototype of the OFFSET (Optical Fiber Folded Scintillating Extended Tracker) tracker is presented. It exploits a novel system for particle tracking, designed to achieve real-time imaging, large detection areas, and a high spatial resolution especially suitable for use in medical diagnostics. The main results regarding the system architecture have been used as a demonstration of the technique which has been patented by the Istituto Nazionale di Fisica Nucleare (INFN). The prototype of this tracker, presented in this paper, has a 20 × 20 cm2 sensitive area, consisting of two crossed ribbons of 500 micron square scintillating fibers. The track position information is extracted in real time in an innovative way, using a reduced number of read-out channels to obtain very large detection area with moderate enough costs and complexity. The performance of the tracker was investigated using beta sources, cosmic rays, and a 62 MeV proton beam.

  8. Impact of electron irradiation on particle track etching response in polyallyl diglycol carbonate (PADC)

    Indian Academy of Sciences (India)

    R Mishra; S P Tripathy; A Kulshrestha; A Srivastava; S Ghosh; K K Dwivedi; D T Khathing; M Müller; D Fink

    2000-05-01

    In the present work, attempts have been made to investigate the modification in particle track etching response of polyallyl diglycol carbonate (PADC) due to impact of 2 MeV electrons. PADC samples pre-irradiated to 1, 10, 20, 40, 60, 80 and 100 Mrad doses of 2 MeV electrons were further exposed to 140 MeV 28Si beam and dose-dependent track registration properties of PADC have been studied. Etch-rate values of the PADC irradiated to 100 Mrad dose electron was found to increase by nearly 4 times that of pristine PADC. The electron irradiation has promoted chain scissioning in PADC, thereby converting the polymer into an easily etchable polymer. Moreover, the etching response and the detection efficiency were found to improve by electron irradiation. Scanning electron microscopy of etched samples further revealed the surface damage in these irradiated PADCs

  9. Development of a scintillation-fiber detector for real-time particle tracking

    Science.gov (United States)

    Lo Presti, D.; Bonanno, D. L.; Longhitano, F.; Pugliatti, C.; Russo, G. V.; Aiello, S.; Cirrone, G. A. P.; Giordano, V.; Leonora, E.; Randazzo, N.; Romano, F.; Russo, M.; Sipala, V.; Stancampiano, C.; Reito, S.

    2013-04-01

    The prototype of the OFFSET (Optical Fiber Folded Scintillating Extended Tracker) tracker is presented. It exploits a novel system for particle tracking, designed to achieve real-time imaging, large detection areas, and a high spatial resolution especially suitable for use in medical diagnostics. The main results regarding the system architecture have been used as a demonstration of the technique which has been patented by the Istituto Nazionale di Fisica Nucleare (INFN). The prototype of this tracker, presented in this paper, has a 20 × 20 cm2 sensitive area, consisting of two crossed ribbons of 500 micron square scintillating fibers. The track position information is extracted in real time in an innovative way, using a reduced number of read-out channels to obtain very large detection area with moderate enough costs and complexity. The performance of the tracker was investigated using beta sources, cosmic rays, and a 62 MeV proton beam.

  10. Track Reconstruction and Performance of DRIFT Directional Dark Matter Detectors using Alpha Particles

    CERN Document Server

    Burgos, S; Ghag, C; Gold, M; Kudryavtsev, V A; Lawson, T B; Loomba, D; Majewski, P; McMillan, J E; Muna, D; Murphy, A StJ; Nicklin, G G; Paling, S M; Petkov, A; Plank, S J S; Robinson, M; Sanghi, N; Smith, N J T; Snowden-Ifft, D P; Spooner, N J C; Sumner, T J; Turk, J; Tziaferi, T

    2007-01-01

    First results are presented from an analysis of data from the DRIFT-IIa and DRIFT-IIb directional dark matter detectors at Boulby Mine in which alpha particle tracks were reconstructed and used to characterise detector performance--an important step towards optimising directional technology. The drift velocity in DRIFT-IIa was [59.3 +/- 0.2 (stat) +/- 7.5 (sys)] m/s based on an analysis of naturally-occurring alpha-emitting background. The drift velocity in DRIFT-IIb was [57 +/- 1 (stat) +/- 3 (sys)] m/s determined by the analysis of alpha particle tracks from a Po-210 source. 3D range reconstruction and energy spectra were used to identify alpha particles from the decay of Rn-222, Po-218, Rn-220 and Po-216. This study found that (22 +/- 2)% of Po-218 progeny (from Rn-222 decay) are produced with no net charge in 40 Torr CS2. For Po-216 progeny (from Rn-220 decay) the uncharged fraction is (100 +0 -35)%.

  11. Particle tracking velocimetry using echocardiographic data resolves flow in the left ventricle

    Science.gov (United States)

    Sampath, Kaushik; Abd, Thura T.; George, Richard T.; Katz, Joseph

    2015-11-01

    Two dimensional contrast echocardiography was performed on patients with a history of left ventricular (LV) thrombus. The 636 x 434 pixels electrocardiograms were recorded using a GE Vivid 9E system with (M5S-D and 4V-D) probes in a 2-D mode at a magnification of 0.3 mm/pix. The concentration of 2-4.5 micron seed bubbles was adjusted to obtain individually discernable traces, and a data acquisition rate of 60-90 fps kept the inter-frame displacements suitable for matching traces, and calculating vectors, but yet low enough to allow a scanning depth and width of upto 13 cm and 60 degrees respectively. Particle tracking velocimetry (PTV) guided by initial particle image velocimetry (PIV) was used to obtain the velocity distributions inside the LV with vector spacing of 3-5 mm. The data quality was greatly enhanced by implementing an iterative particle specific enhancement and tracking algorithm. Data covering 20 heart beats facilitated phase averaging. The results elucidated blood flow in the intra-ventricular septal region, lateral wall region, the apex of the LV and the mitral valve region.

  12. PTRACK: A particle tracking program for evaluation travel path/travel time uncertainties

    International Nuclear Information System (INIS)

    PTRACK is a model which tracks the path of a radionuclide particle released from a nuclear waste repository into a ground-water flow system in a two-dimensional representation of stratified geologic medium. The code calculates the time required for the particle to travel from the release point (the edge of the disturbed zone) to the specified horizontal or vertical boundary (the accessible environment). The physical properties of the geologic setting and the ground-water flow system can be treated as fixed values or as random variables sampled from their respective probability distributions. In the latter case, PTRACK assigns a sampled value for each parameter and tracks a particle for this trial (realization) of the system. Repeated realizations allow the effects of parameter uncertainty on travel paths/travel times to be quantified. The code can also calculate partial correlation coefficients between dependent variables and independent variables, which are useful in identifying important independent variables. This documentation describes the mathematical basis for the model, the algorithms and solution techniques used, and the computer code design. It also contains a detailed user's manual. The implementation of PTRACK is verified with several systems for which solutions have been calculated by hand. The integration of PTRACK with a Latin hypercube sampling (LHS) code is also discussed, although other sampling methods can be employed in place of LHS. 11 refs., 14 figs., 22 tabs

  13. Embedded Analytical Solutions Improve Accuracy in Convolution-Based Particle Tracking Models using Python

    Science.gov (United States)

    Starn, J. J.

    2013-12-01

    Particle tracking often is used to generate particle-age distributions that are used as impulse-response functions in convolution. A typical application is to produce groundwater solute breakthrough curves (BTC) at endpoint receptors such as pumping wells or streams. The commonly used semi-analytical particle-tracking algorithm based on the assumption of linear velocity gradients between opposing cell faces is computationally very fast when used in combination with finite-difference models. However, large gradients near pumping wells in regional-scale groundwater-flow models often are not well represented because of cell-size limitations. This leads to inaccurate velocity fields, especially at weak sinks. Accurate analytical solutions for velocity near a pumping well are available, and various boundary conditions can be imposed using image-well theory. Python can be used to embed these solutions into existing semi-analytical particle-tracking codes, thereby maintaining the integrity and quality-assurance of the existing code. Python (and associated scientific computational packages NumPy, SciPy, and Matplotlib) is an effective tool because of its wide ranging capability. Python text processing allows complex and database-like manipulation of model input and output files, including binary and HDF5 files. High-level functions in the language include ODE solvers to solve first-order particle-location ODEs, Gaussian kernel density estimation to compute smooth particle-age distributions, and convolution. The highly vectorized nature of NumPy arrays and functions minimizes the need for computationally expensive loops. A modular Python code base has been developed to compute BTCs using embedded analytical solutions at pumping wells based on an existing well-documented finite-difference groundwater-flow simulation code (MODFLOW) and a semi-analytical particle-tracking code (MODPATH). The Python code base is tested by comparing BTCs with highly discretized synthetic steady

  14. Asynchronous Power Flow Controller

    Directory of Open Access Journals (Sweden)

    Rahul Juneja

    2014-04-01

    Full Text Available In the present system demand of electrical power increases so fast and transfer of electrical power is need of today‟s scenario. . The electrical power is transfer at same frequency through AC transmission line. However, power generation may be at different frequencies such as wind generation, sources at islanding or power generation in different countries. The proposed Asynchronous Power Flow Controller (APFC system essentially consists of two back-to-back voltage source converters as “Shunt Converter” and “Series Converter” which is coupled via a common dc link provided by a dc storage capacitor This paper suggests the power transfer and control between the sources operating at different or same frequencies.

  15. Strategy for fitting source strength and reconstruction procedure in radioactive particle tracking

    International Nuclear Information System (INIS)

    The Radioactive Particle Tracking (RPT) technique is widely applied to study the dynamic properties of flows inside a reactor. Usually, a single radioactive particle that is neutrally buoyant with respect to the phase is used as a tracker. The particle moves inside a 3D volume of interest, and its positions are determined by an array of scintillation detectors, which count the incoming photons. The particle position coordinates are calculated by using a reconstruction procedure that solves a minimization problem between the measured counts and calibration data. Although previous studies have described the influence of specified factors on the RPT resolution and sensitivities, the question of how to choose an appropriate source strength and reconstruction procedure for the given RPT setup remains an unsolved problem. This work describes and applies the original strategy for fitting both the source strength and the sampling time interval to a specified RPT setup to guarantee a required accuracy of measurements. Additionally, the measurement accuracy of an RPT setup can be significantly increased by changing the reconstruction procedure. The results of the simulations, based on the Monte Carlo approach, have demonstrated that the proposed strategy allows for the successful implementation of the As Low As Reasonably Achievable (ALARA) principle when designing the RPT setup. The limitations and drawbacks of the proposed procedure are also presented. - Highlights: • We develop an original strategy for fitting source strength and measurement time interval in radioactive particle tracking (RPT) technique. • The proposed strategy allows successfully to implement the ALAPA (As Low As Reasonably Achievable) principle in designing of a RPT setup. • Measurement accuracy of a RPT setup can be significantly increased by improvement of the reconstruction procedure. • The algorithm can be applied to monitor the motion of the radioactive tracer in a reactor

  16. A self-adaptive oriented particles Level-Set method for tracking interfaces

    Science.gov (United States)

    Ianniello, S.; Di Mascio, A.

    2010-02-01

    A new method for tracking evolving interfaces by lagrangian particles in conjunction with a Level-Set approach is introduced. This numerical technique is based on the use of time evolution equations for fundamental vector and tensor quantities defined on the front and represents a new and convenient way to couple the advantages of the Eulerian description given by a Level-Set function ϕ to the use of Lagrangian massless particles. The term oriented points out that the information advected by the particles not only concern the spatial location, but also the local (outward) normal vector n to the interface Γ and the second fundamental tensor (the shape operator) ∇n. The particles are exactly located upon Γ and provide all the requested information for tracking the interface on their own. In addition, a self-adaptive mechanism suitably modifies, at each time step, the markers distribution in the numerical domain: each particle behaves both as a potential seeder of new markers on Γ (so as to guarantee an accurate reconstruction of the interface) and a de-seeder (to avoid any useless gathering of markers and to limit the computational effort). The algorithm is conceived to avoid any transport equation for ϕ and to confine the Level-Set function to the role of a mere post-processing tool; thus, all the numerical diffusion problems usually affecting the Level-Set methodology are removed. The method has been tested both on 2D and 3D configurations; it carries out a fast reconstruction of the interface and its accuracy is only limited by the spatial resolution of the mesh.

  17. Operator tracking system using particle filter for skill evaluation in nuclear power plant control room

    International Nuclear Information System (INIS)

    This article proposes an automated operator tracking system by the use of particle filter and image processing technology to help operator skill evaluation in nuclear power plant operator training facilities. In each of the control room of the training facilities, a full-scope plant simulator with mock-up control panels are used for real-time operator training. At this point, the operators' behaviors and plant's events are recorded as video-log and event-log, by a multi-media recording system to evaluate operators' skills at training review meetings in which the instructors and trainees discuss each of their action during the training process. Multiple cameras that are placed on the control room ceiling are used in the recording system. However, the views from these cameras are limited and therefore it is not possible to thoroughly check how each of the operator approaches the target panel within an appropriate timing that corresponds to the plant's event. For example, the instructors have to estimate operators' real-world position from the views; and in some cases other operators might conceal the target operators from the cameras. The purpose of the proposed system is to help checking whether the position and timing of each operator is appropriate during each event or alarm occurrence, by tracking the operators from the recorded video. To achieve this objective, the real-time image processing technology is newly introduced in this study, where particle filter is one of convenient algorithms for operator tracking. In this algorithm, the main issue is how to recognize multiple operators from the background and to get their positions within the coordinates of the control room. For this purpose, one 3-D particle filter is used for each operator wearing colored vests and the similarity calculation algorithm is based on color histogram. The particles are directly placed inside the control room. By converting the particle coordinates into camera coordinates and taking

  18. Fission track-secondary ion mass spectrometry as a tool for detecting the isotopic signature of individual uranium containing particles.

    Science.gov (United States)

    Esaka, Fumitaka; Lee, Chi-Gyu; Magara, Masaaki; Kimura, Takaumi

    2012-04-01

    A fission track technique was used as a sample preparation method for subsequent isotope abundance ratio analysis of individual uranium containing particles with secondary ion mass spectrometry (SIMS) to measure the particles with higher enriched uranium efficiently. A polycarbonate film containing particles was irradiated with thermal neutrons and etched with 6M NaOH solution. Each uranium containing particle was then identified by observing fission tracks created and a portion of the film having a uranium containing particle was cut out and put onto a glassy carbon planchet. The polycarbonate film, which gave the increases of background signals on the uranium mass region in SIMS analysis, was removed by plasma ashing with 200 W for 20 min. In the analysis of swipe samples having particles containing natural (NBL CRM 950a) or low enriched uranium (NBL CRM U100) with the fission track-SIMS method, uranium isotope abundance ratios were successfully determined. This method was then applied to the analysis of a real inspection swipe sample taken at a nuclear facility. As a consequence, the range of (235)U/(238)U isotope abundance ratio between 0.0276 and 0.0438 was obtained, which was higher than that measured by SIMS without using a fission track technique (0.0225 and 0.0341). This indicates that the fission track-SIMS method is a powerful tool to identify the particle with higher enriched uranium in environmental samples efficiently. PMID:22405310

  19. Pro asynchronous programming with .NET

    CERN Document Server

    Blewett, Richard; Ltd, Rock Solid Knowledge

    2014-01-01

    Pro Asynchronous Programming with .NET teaches the essential skill of asynchronous programming in .NET. It answers critical questions in .NET application development, such as: how do I keep my program responding at all times to keep my users happy how do I make the most of the available hardware how can I improve performanceIn the modern world, users expect more and more from their applications and devices, and multi-core hardware has the potential to provide it. But it takes carefully crafted code to turn that potential into responsive, scalable applications.With Pro Asynchronous Programming

  20. A novel CMOS sensor with in-pixel auto-zeroed discrimination for charged particle tracking

    International Nuclear Information System (INIS)

    With the aim of developing fast and granular Monolithic Active Pixels Sensors (MAPS) as new charged particle tracking detectors for high energy physics experiments, a new rolling shutter binary pixel architecture concept (RSBPix) with in-pixel correlated double sampling, amplification and discrimination is presented. The discriminator features auto-zeroing in order to compensate process-related transistor mismatches. In order to validate the pixel, a first monolithic CMOS sensor prototype, including a pixel array of 96 × 64 pixels, has been designed and fabricated in the Tower-Jazz 0.18 μm CMOS Image Sensor (CIS) process. Results of laboratory tests are presented

  1. Potential of Thin Films for use in Charged Particle Tracking Detectors

    CERN Document Server

    Metcalfe, J; Murphy, J; Quevedo, M; Smith, L; Alvarado, J; Gnade, B; Takai, H

    2014-01-01

    Thin Film technology has widespread applications in everyday electronics, notably Liquid Crystal Display screens, solar cells, and organic light emitting diodes. We explore the potential of this technology as charged particle radiation tracking detectors for use in High Energy Physics experiments such as those at the Large Hadron Collider or the Relativistic Heavy Ion Collider. Through modern fabrication techniques, a host of semiconductor materials are available to construct thin, flexible detectors with integrated electronics with pixel sizes on the order of a few microns. We review the material properties of promising candidates, discuss the potential benefits and challenges associated with this technology, and review previously demonstrated applicability as a neutron detector.

  2. Tracking reactive pollutants in large groundwater systems by particle-based simulations

    Science.gov (United States)

    Kalbacher, T.; Sun, Y.; He, W.; Jang, E.; Delfs, J.; Shao, H.; Park, C.; Kolditz, O.

    2013-12-01

    Worldwide, great amounts of human and financial resources are being invested to protect and secure clean water resources. Especially in arid and semi-arid regions civilization depends on the availability of freshwater from the underlying aquifer systems where water quality and quantity are often dramatically deteriorating. Main reasons for the mitigation of water quality are extensive fertilizer use in agriculture and waste water from cities and various industries. It may be assumed that climate and demographic changes will add further stress to this situation in the future. One way to assess water quality is to model the coupled groundwater and chemical system, e.g.to assess the impact of possible contaminant precipitation, absorption and migration in subsurface media. Currently, simulating such scenarios at large scales is a challenging task due to the extreme computational load, numerical stability issues, scale-dependencies and spatially and temporally infrequently distributed or missing data, which can lead e.g. to in appropriate model simplifications and additionally uncertainties in the results. The simulation of advective-dispersive mass transport is usually solved by standard finite differences, finite element or finite volume methods. Particle tracking is an alternative method and commonly used e.g. to delineate contaminant travel times, with the advantage of being numerically more stable and computational less expensive. Since particle tracking is used to evaluate groundwater residence times, it seems natural and straightforward to include reactive processes to track geochemical changes as well. The main focus of the study is the evaluation of reactive transport processes at large scales. Therefore, a number of new methods have been developed and implemented into the OpenGeoSys project, which is a scientific, FEM-based, open source code for numerical simulation of thermo-hydro-mechanical-chemical processes in porous and fractured media (www

  3. Proceedings of the 3. conference: Particle track membranes and their applications

    International Nuclear Information System (INIS)

    The materials of the 3rd conference on Particle Track Membranes and Theirs Applications present actual state of art in the topic. The leading world institutions have presented their works on the technology of PTM production by interaction of ion beams with polymeric foils. The broad spectrum of PTM membranes have been shown, their properties have been described and their applicability discussed. A number of possible applications of PTM and also already realized in industry, medicine, biology and physical investigations have been presented. 29 lectures have been made in the course of conference

  4. Numerical analyses of boiling two-phase bubbly flows in pipes with particle tracking method

    International Nuclear Information System (INIS)

    The present study deals with the numerical modeling of two-phase bubbly flows with subcooled boiling in a flow channel using Particle Tracking Method. It is an on-going project whose final aim is to develop a computer code to more accurately predict, and better understand, the Departure from Nuclear Boiling (DNB) under PWR accidental conditions. At the first stage of the present study, this presentation reports the development of bubble dynamics models such as the bubble coalesces/break models and bubble heat transfer models. The validation of the models by comparing simulation results with experimental data in literature is also reported. (author)

  5. Method for predicting DNB power of subcooled boiling flows in pipes with particle tracking method

    International Nuclear Information System (INIS)

    Numerical modeling and prediction method of DNB powers are reported of two-phase bubbly flows with subcooled boiling in a flow channel using Particle Tracking Method. This study is aimed at developing a computer code to more accurately predict, and better understand, the Departure from Nuclear Boiling (DNB) under PWR accidental conditions. This presentation reports the modeling of bubble behavior near the heated wall and development of a prediction method for DNB power under subcooled, high-pressure conditions. The validation of the DNB model by comparing prediction with experimental data in literature is also reported. (author)

  6. A fully automated optical microscope for analysis of particle tracks in solids

    Science.gov (United States)

    Dolleiser, M.; Hashemi-Nezhad, S. R.

    2002-12-01

    A fully automatic optical microscope (FAOM) for on-line analysis of micro-objects is described. The system has many capabilities, such as autofocusing, autocounting, autoscanning, producing optical images corresponding to different depths in the sample, contour and edge finding, etc. The autofocusing can be achieved with more than one method. The system can be used for analysis and counting (high-density) micro-objects, such as particle tracks in plastic detectors. The processing speed of the system is adequate and it can be used in analysis of macro samples. The software of the FAOM is written in C++ and runs under Microsoft Windows operating systems.

  7. A fully automated optical microscope for analysis of particle tracks in solids

    CERN Document Server

    Dolleiser, M

    2002-01-01

    A fully automatic optical microscope (FAOM) for on-line analysis of micro-objects is described. The system has many capabilities, such as autofocusing, autocounting, autoscanning, producing optical images corresponding to different depths in the sample, contour and edge finding, etc. The autofocusing can be achieved with more than one method. The system can be used for analysis and counting (high- density) micro-objects, such as particle tracks in plastic detectors. The processing speed of the system is adequate and it can be used in analysis of macro samples. The software of the FAOM is written in C++ and runs under Microsoft Windows operating systems. (8 refs).

  8. A fully automated optical microscope for analysis of particle tracks in solids

    International Nuclear Information System (INIS)

    A fully automatic optical microscope (FAOM) for on-line analysis of micro-objects is described. The system has many capabilities, such as autofocusing, autocounting, autoscanning, producing optical images corresponding to different depths in the sample, contour and edge finding, etc. The autofocusing can be achieved with more than one method. The system can be used for analysis and counting (high-density) micro-objects, such as particle tracks in plastic detectors. The processing speed of the system is adequate and it can be used in analysis of macro samples. The software of the FAOM is written in C++ and runs under Microsoft Windows operating systems

  9. Proceedings of the 3. conference: Particle track membranes and their applications

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-31

    The materials of the 3rd conference on Particle Track Membranes and Theirs Applications present actual state of art in the topic. The leading world institutions have presented their works on the technology of PTM production by interaction of ion beams with polymeric foils. The broad spectrum of PTM membranes have been shown, their properties have been described and their applicability discussed. A number of possible applications of PTM and also already realized in industry, medicine, biology and physical investigations have been presented. 29 lectures have been made in the course of conference.

  10. Feasibility study of radioactive particle tracking in a draft tube column

    International Nuclear Information System (INIS)

    Lagrangian particle trajectories can be transformed to a classical residence time distribution, time-averaged velocity flow fields, the fluctuating velocities, turbulence, etc. The RPT technique is non-invasive, and can be performed in non-opaque systems where other techniques, like ultrasonic methods, laser velocimetry technique, etc., fail. In this study, RPT experiments were carried out with a propeller driven draft tube column. 24 NaI scintillation detectors strategically placed around the vessel are used to monitor the position of the tracer particle. The positions of the particle were determined by a Monte Calro based reconstruction method from the radiation measurement data. The results were compared with Computational Fluid Dynamics numerical simulations for validation. The radioactive particle tracking technique was applied to investigate the characteristics of water flow for the draft tube column. The trajectory of the tracer particle was successfully reconstructed using the Monte Carlo method. The mean circulation time was calculated to be about 48 s by both the RPT experiment and CFD simulation

  11. Mineralogy of Stardust Track 112 Particle: Relation to Amoeboid Olivine Aggregates

    Science.gov (United States)

    Komatsu, M.; Fagan, T.; Mikouchi, T.; Miyamoto, M.; Zolensky, M.; Ohsumi, K.

    2012-01-01

    The successful analysis of comet 81P/Wild 2 particles returned by the Stardust mission has revealed that the Wild 2 dust contains abundant silicate grains that are much larger than interstellar grains and appear to have formed in the inner regions of the solar nebula [1]. Wild 2 particles include minerals which are isotopically and mineralogically similar to CAIs [e.g., 2, 3] and chondrules [e.g., 4] in chondrites. In addition, particles similar to amoeboid olivine aggregates (AOAs) also have been discovered [5, 6,7]. C2067,2,112,1 is a terminal particle recovered from track #112 (T112). Nakamura-Messenger et al. [7] showed that the forsterite grain in T112 has O-16 enrichment of approximately 40 0/00 (vs. SMOW) and possibly formed together with AOAs. In this study, we have examined the mineralogy of the T112 particle and compared the possible relationships between T112 and AOAs in primitive meteorites.

  12. Improved estimation of anomalous diffusion exponents in single-particle tracking experiments

    Science.gov (United States)

    Kepten, Eldad; Bronshtein, Irena; Garini, Yuval

    2013-05-01

    The mean square displacement is a central tool in the analysis of single-particle tracking experiments, shedding light on various biophysical phenomena. Frequently, parameters are extracted by performing time averages on single-particle trajectories followed by ensemble averaging. This procedure, however, suffers from two systematic errors when applied to particles that perform anomalous diffusion. The first is significant at short-time lags and is induced by measurement errors. The second arises from the natural heterogeneity in biophysical systems. We show how to estimate and correct these two errors and improve the estimation of the anomalous parameters for the whole particle distribution. As a consequence, we manage to characterize ensembles of heterogeneous particles even for rather short and noisy measurements where regular time-averaged mean square displacement analysis fails. We apply this method to both simulations and in vivo measurements of telomere diffusion in 3T3 mouse embryonic fibroblast cells. The motion of telomeres is found to be subdiffusive with an average exponent constant in time. Individual telomere exponents are normally distributed around the average exponent. The proposed methodology has the potential to improve experimental accuracy while maintaining lower experimental costs and complexity.

  13. A Framework for Sediment Particle Tracking via Radio Frequency IDentification (RFID)

    Science.gov (United States)

    Tsakiris, Achilleas; Papanicolaou, Thanos; Abban, Benjamin

    2016-04-01

    The study of sedimentary and morphodynamic processes in riverine environments has recently been shifting from the traditional Eulerian, static perspective to a Lagrangian perspective, which considers the movement characteristics of the individual transported particles, such as their travel and resting distance and time. The Lagrangian framework, in turn allows to better study processes such as bedload particle diffusion, erosion and deposition within a river reach, to more accurately predict bedload fluxes especially through the use of stochastic Discrete Particle models. A technology that goes hand-in-hand with this Lagrangian perspective is Radio Frequency IDentification (RFID), which has been recently applied for tracking the movement of tagged sediment particles within the river continuum. RFID allows the wireless, bidirectional exchange of information between a base station, known as the reader, with a typically large number of transponders (or tags) via an (excitation) antenna. RFID allows essentially the unique, wireless detection and identification of a transponder over a distance. The goal of this study is to further enhance the utility of RFID in riverine applications by developing a framework that allows extracting the 3D location of RFID tagged sediment particles in nearly real-time. To address the goal of this coupled theoretical and experimental study, a semi-theoretical approach based on antenna inductive coupling was combined with experimental measurements for developing a relationship that provides an estimate of the distance between a tagged particle and the antenna using the Return Signal Strength Indication (RSSI). The RSSI quantifies the magnetic energy transmitted from the transponder to the antenna. The RFID system used in this study was a passive, Low-Frequency (LF) system, which ensured that the LF radio waves could penetrate through the river bed material. The RSSI of the signal transmitted from each transponder was measured with an

  14. Guidelines for the fitting of anomalous diffusion mean square displacement graphs from single particle tracking experiments.

    Directory of Open Access Journals (Sweden)

    Eldad Kepten

    Full Text Available Single particle tracking is an essential tool in the study of complex systems and biophysics and it is commonly analyzed by the time-averaged mean square displacement (MSD of the diffusive trajectories. However, past work has shown that MSDs are susceptible to significant errors and biases, preventing the comparison and assessment of experimental studies. Here, we attempt to extract practical guidelines for the estimation of anomalous time averaged MSDs through the simulation of multiple scenarios with fractional Brownian motion as a representative of a large class of fractional ergodic processes. We extract the precision and accuracy of the fitted MSD for various anomalous exponents and measurement errors with respect to measurement length and maximum time lags. Based on the calculated precision maps, we present guidelines to improve accuracy in single particle studies. Importantly, we find that in some experimental conditions, the time averaged MSD should not be used as an estimator.

  15. Fast Three-Dimensional Single-Particle Tracking in Natural Brain Tissue.

    Science.gov (United States)

    Sokoll, Stefan; Prokazov, Yury; Hanses, Magnus; Biermann, Barbara; Tönnies, Klaus; Heine, Martin

    2015-10-01

    Observation of molecular dynamics is often biased by the optical very heterogeneous environment of cells and complex tissue. Here, we have designed an algorithm that facilitates molecular dynamic analyses within brain slices. We adjust fast astigmatism-based three-dimensional single-particle tracking techniques to depth-dependent optical aberrations induced by the refractive index mismatch so that they are applicable to complex samples. In contrast to existing techniques, our online calibration method determines the aberration directly from the acquired two-dimensional image stream by exploiting the inherent particle movement and the redundancy introduced by the astigmatism. The method improves the positioning by reducing the systematic errors introduced by the aberrations, and allows correct derivation of the cellular morphology and molecular diffusion parameters in three dimensions independently of the imaging depth. No additional experimental effort for the user is required. Our method will be useful for many imaging configurations, which allow imaging in deep cellular structures. PMID:26445447

  16. PSO Algorithm Particle Filters for Improving the Performance of Lane Detection and Tracking Systems in Difficult Roads

    Directory of Open Access Journals (Sweden)

    Wen-Chang Cheng

    2012-12-01

    Full Text Available In this paper we propose a robust lane detection and tracking method by combining particle filters with the particle swarm optimization method. This method mainly uses the particle filters to detect and track the local optimum of the lane model in the input image and then seeks the global optimal solution of the lane model by a particle swarm optimization method. The particle filter can effectively complete lane detection and tracking in complicated or variable lane environments. However, the result obtained is usually a local optimal system status rather than the global optimal system status. Thus, the particle swarm optimization method is used to further refine the global optimal system status in all system statuses. Since the particle swarm optimization method is a global optimization algorithm based on iterative computing, it can find the global optimal lane model by simulating the food finding way of fish school or insects under the mutual cooperation of all particles. In verification testing, the test environments included highways and ordinary roads as well as straight and curved lanes, uphill and downhill lanes, lane changes, etc. Our proposed method can complete the lane detection and tracking more accurately and effectively then existing options.

  17. Identification of DNA double strand breaks at chromosome boundaries along the track of particle irradiation.

    Science.gov (United States)

    Niimi, Atsuko; Yamauchi, Motohiro; Limsirichaikul, Siripan; Sekine, Ryota; Oike, Takahiro; Sato, Hiro; Suzuki, Keiji; Held, Kathryn D; Nakano, Takashi; Shibata, Atsushi

    2016-08-01

    Chromosomal translocations arise from misrejoining of DNA double strand breaks (DSBs) between loci located on two chromosomes. One current model suggests that spatial proximity of potential chromosomal translocation partners influences translocation probability. Ionizing radiation (IR) is a potent inducer of translocations. Accumulating evidence demonstrates that particle irradiation more frequently causes translocations compared with X-ray irradiation. This observation has led to the hypothesis that the high frequency of translocations after particle irradiation may be due to the formation of DSBs at chromosome boundaries along the particle track, because such DSBs can be misrejoined between distinct chromosomes. In this study, we simultaneously visualized the site of IR-induced DSBs and chromosome position by combining Immunofluorescence and fluorescence in situ hybridization. Importantly, the frequency of γH2AX foci at the chromosome boundary of chromosome 1 after carbon-ion irradiation was >4-fold higher than that after X-ray irradiation. This observation is consistent with the idea that particle irradiation generates DSBs at the boundaries of two chromosomes along the track. Further, we showed that resolution of γH2AX foci at chromosome boundaries is prevented by inhibition of DNA-PKcs activity, indicating that the DSB repair is NHEJ-dependent. Finally, we found that γH2AX foci at chromosome boundaries after carbon-ion irradiation contain DSBs undergoing DNA-end resection, which promotes repair utilizing microhomology mediated end-joining during translocation. Taken together, our study suggests that the frequency of DSB formation at chromosome boundaries is associated with the incidence of chromosomal translocations, supporting the notion that the spatial proximity between breaks is an important factor in translocation formation. © 2016 Wiley Periodicals, Inc. PMID:27113385

  18. Reducing energy with asynchronous circuits

    OpenAIRE

    Rivas Barragan, Daniel

    2012-01-01

    Reducing energy consumption using asynchronous circuits. The elastic clocks approach has been implemented along with a closed-feedback loop in order to achieve a lower energy consumption along with more reliability in integrated circuits.

  19. In Situ Particle Tracking around kW Sized Wind Turbines

    Science.gov (United States)

    Brownstein, Ian; Dabiri, John

    2015-11-01

    Laboratory studies of model wind turbines are typically unable to match both the Reynolds number (Re) and tip speed ratio (TSR) of full-scale wind turbines. In order to match both relevant parameters, a quantitative flow visualization method was developed to take in situ measurements of the flow around full-scale wind turbines. The apparatus constructed was able to seed an approximately 9mx9mx5m volume in the wake of the turbine using artificial snow. Quantitative results were obtained by tracking the evolution of the snow using particle tracking algorithms. As a step toward full 3D-PTV measurements, results will be presented in which a 2D measurement is taken with a single camera positioned at the base of the turbine looking upward. The resulting tracking is therefore integrated in the span-wise direction. This method is demonstrated through a comparative study of a five-bladed VAWT producing power in different wind conditions at the Field Laboratory for Optimized Wind Energy (FLOWE) in Lancaster, CA. Future work to expand this method to 3D-PTV is also discussed.

  20. Principles and biophysical applications of single particle super-localization and rotational tracking

    Science.gov (United States)

    Gu, Yan

    While conventional Single Particle Tracking (SPT) techniques acquire 2D or 3D trajectories of particle probes, we have developed Single Particle Orientation and Rotational Tracking (SPORT) techniques to extract orientation and rotational information. Combined with DIC microscopy, the SPORT technique has been applied in biophysical studies, including membrane diffusion and intracellular transport. The rotational dynamics of nanoparticle vectors on live cell membranes was recorded and its influence on the fate of these nanoparticle vectors was elucidated. The rotational motions of gold nanorods with various surface modifiers were tracked continuously at a temporal resolution of 5 ms under a DIC microscope. We found that the rotational behaviors of gold nanorod vectors are strongly related to their surface charge, specific surface functional groups, and the availability of receptors on cell membranes. The study of rotational Brownian motion of nanoparticles on cell membranes will lead to a better understanding of the mechanisms of drug delivery and provide guidance in designing surface modification strategies for drug delivery vectors under various circumstances. To characterize the rotation mode of surface functionalized gold nanorods on cell membranes, the SPORT technique is combined with the correlation analysis of the bright and dark DIC intensities. The unique capabilities of visualizing and understanding rotational motions of functionalized nanoparticles on live cell membranes allow us to correlate rotational and translational dynamics in unprecedented detail and provide new insights for complex membrane processes, including electrostatic interactions, ligand-receptor binding, and lateral (confined and hopping) diffusion of membrane receptors. Surface-functionalized nanoparticles interact with the membrane in fundamentally different ways and exhibit distinct rotational modes. The early events of particle-membrane approach and attachment are directly visualized

  1. Principles and biophysical applications of single particle super-localization and rotational tracking

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Yan [Iowa State Univ., Ames, IA (United States)

    2013-01-01

    While conventional Single Particle Tracking (SPT) techniques acquire 2D or 3D trajectories of particle probes, we have developed Single Particle Orientation and Rotational Tracking (SPORT) techniques to extract orientation and rotational information. Combined with DIC microscopy, the SPORT technique has been applied in biophysical studies, including membrane diffusion and intracellular transport. The rotational dynamics of nanoparticle vectors on live cell membranes was recorded and its influence on the fate of these nanoparticle vectors was elucidated. The rotational motions of gold nanorods with various surface modifiers were tracked continuously at a temporal resolution of 5 ms under a DIC microscope. We found that the rotational behaviors of gold nanorod vectors are strongly related to their surface charge, specific surface functional groups, and the availability of receptors on cell membranes. The study of rotational Brownian motion of nanoparticles on cell membranes will lead to a better understanding of the mechanisms of drug delivery and provide guidance in designing surface modification strategies for drug delivery vectors under various circumstances. To characterize the rotation mode of surface functionalized gold nanorods on cell membranes, the SPORT technique is combined with the correlation analysis of the bright and dark DIC intensities. The unique capabilities of visualizing and understanding rotational motions of functionalized nanoparticles on live cell membranes allow us to correlate rotational and translational dynamics in unprecedented detail and provide new insights for complex membrane processes, including electrostatic interactions, ligand-receptor binding, and lateral (confined and hopping) diffusion of membrane receptors. Surface-functionalized nanoparticles interact with the membrane in fundamentally different ways and exhibit distinct rotational modes. The early events of particle-membrane approach and attachment are directly visualized

  2. Interpretation of migration of radionuclides in a rock fracture using a particle tracking method

    International Nuclear Information System (INIS)

    A particle tracking scheme was developed in order to model radionuclide transport through a tortuous flow field in a rock fracture. The particle tracking method may be used effectively in a heterogeneous flow field such as rock fracture. The parallel plate representation of the single fracture fails to recognize the spatial heterogeneity in the fracture aperture and thus seems inadequate in describing fluid movement through a real fracture. The heterogeneous flow field was modeled by a variable aperture channel model after characterizing aperture distribution by a hydraulic test. To support the validation of radionuclide transport models, a radionuclide migration experiment was performed in a natural fracture of granite. 3H2O and 131I are used as tracers. Simulated results were in agreement with experimental result and therefore support the validity of the transport model. Residence time distributions display multipeak curves caused by the fast arrival of solutes traveling along preferential fracture channels and by the much slower arrival of solutes following tortuous routes through the fracture. Results from the modelling of the transport of nonsorbing tracer through the fracture show that diffusion into the interconnected pore space in the rock mass has a significant effect on retardation. 12 figs., 3 tabs., 17 refs. (Author)

  3. Single particle tracking reveals spatial and dynamic organization of the Escherichia coli biofilm matrix

    International Nuclear Information System (INIS)

    Biofilms are communities of surface-adherent bacteria surrounded by secreted polymers known as the extracellular polymeric substance. Biofilms are harmful in many industries, and thus it is of great interest to understand their mechanical properties and structure to determine ways to destabilize them. By performing single particle tracking with beads of varying surface functionalization it was found that charge interactions play a key role in mediating mobility within biofilms. With a combination of single particle tracking and microrheological concepts, it was found that Escherichia coli biofilms display height dependent charge density that evolves over time. Statistical analyses of bead trajectories and confocal microscopy showed inter-connecting micron scale channels that penetrate throughout the biofilm, which may be important for nutrient transfer through the system. This methodology provides significant insight into a particular biofilm system and can be applied to many others to provide comparisons of biofilm structure. The elucidation of structure provides evidence for the permeability of biofilms to microscale objects, and the ability of a biofilm to mature and change properties over time. (paper)

  4. 3D dual-virtual-pinhole assisted single particle tracking microscopy

    Science.gov (United States)

    Ma, Ye; Wang, Yifan; Zhou, Xin; Kuang, Cuifang; Liu, Xu

    2014-07-01

    We propose a novel approach for high-speed, three-dimensional single particle tracking (SPT), which we refer to as dual-virtual-pinhole assisted single particle tracking microscopy (DVPaSPTM). DVPaSPTM system can obtain axial information of the sample without optical or mechanical depth scanning, so as to offer numbers of advantages including faster imaging, improved efficiency and a great reduction of photobleaching and phototoxicity. In addition, by the use of the dual-virtual-pinhole, the effect that the quantum yield exerts to the fluorescent signal can be eliminated, which makes the measurement independent of the surroundings and increases the accuracy of the result. DVPaSPTM system measures the intensity within different virtual pinholes of which the radii are given by the host computer. Axial information of fluorophores can be measured by the axial response curve through the ratio of intensity signals. We demonstrated the feasibility of the proposed method by a series of experiments. Results showed that the standard deviation of the axial measurement was 19.2 nm over a 2.5 μm range with 30 ms temporal resolution.

  5. Track structure based modelling of chromosome aberrations after photon and alpha-particle irradiation.

    Science.gov (United States)

    Friedland, Werner; Kundrát, Pavel

    2013-08-30

    A computational model of radiation-induced chromosome aberrations in human cells within the PARTRAC Monte Carlo simulation framework is presented. The model starts from radiation-induced DNA damage assessed by overlapping radiation track structures with multi-scale DNA and chromatin models, ranging from DNA double-helix in atomic resolution to chromatin fibre loops, heterochromatic and euchromatic regions, and chromosome territories. The repair of DNA double-strand breaks via non-homologous end-joining is followed. Initial spatial distribution and complexity, diffusive motion, enzymatic processing, synapsis and ligation of individual DNA ends from the breaks are simulated. To enable scoring of different chromosome aberration types resulting from improper joining of DNA fragments, the repair module has been complemented by tracking the chromosome origin of the ligated fragments and the positions of centromeres. The modelled motion of DNA ends has sub-diffusive characteristics and corresponds to measured chromatin mobility within time-scales of a few hours. The calculated formation of dicentrics after photon and α-particle irradiation in human fibroblasts is compared to experimental data (Cornforth et al., 2002, Radiat Res 158, 43). The predicted yields of dicentrics overestimate the measurements by factors of five for γ-rays and two for α-particle irradiation. Nevertheless, the observed relative dependence on radiation dose is correctly reproduced. Calculated yields and size distributions of other aberration types are discussed. The present work represents a first mechanistic approach to chromosome aberrations and their kinetics, combining full track structure simulations with detailed models of chromatin and accounting for the kinetics of DNA repair. PMID:23811166

  6. Development of multi-spectral three-dimensional micro particle tracking velocimetry

    Science.gov (United States)

    Tien, Wei-Hsin

    2016-08-01

    The color-coded 3D micro particle tracking velocimetry system (CC3DμPTV) is a volumetric velocimetry technique that uses the defocusing digital particle image velocimetry (DDPIV) approach to reconstruct the 3D location of the particle. It is suited for microscopic flow visualization because of the single camera configuration. However, several factors limit the performance of the system. In this study, the limitation of the CC3DμPTV is discussed in detail and a new concept of a multi-camera 3D μ-PTV system is proposed to improve the performance of the original CC3DμPTV system. The system utilizes two dichroic beam splitters to separate the incoming light into 3 spectral ranges, and image with three monochrome image sensors. The use of a color-matched light source, off-center individual pinhole and monochrome image sensors allow the system to achieve better sensitivity and optical resolution. The use of coherent lasers light sources with high-speed cameras improves the velocity measurement dynamic range. The performance of the proposed multi-spectral system is first evaluated with a simulation model based on the finite element method (FEM). The performance is also compared numerically with the CC3DμPTV system. The test results show significant improvements on the signal to noise ratio and optical resolution. Originally presented in 11th International Symposium on Particle Image Velocimetry, Santa Barbara, California, September 14–16, 2015.

  7. Application of fission track technique for the analysis of individual particles containing uranium in safeguard swipe samples

    International Nuclear Information System (INIS)

    An effective method for isotope ratio analysis of individual particles containing uranium in safeguard swipe samples was developed by using a fission track (FT) technique combined with thermal ionization mass spectrometry (TIMS). The particles in the sample were directly recovered onto a polycarbonate membrane filter, which was set in a filtration system. After the particle recovery, the filter was dissolved to form a non coated FT detector film containing the particles. Individual particles containing uranium were then identified by the observation of fission tracks created by thermal neutron irradiation. By combining the FT technique with TIMS, isotope ratios of uranium for individual particles in the swipe sample prepared from a uranium standard reference material could be effectively determined. (author)

  8. A Hidden Markov Model for Single Particle Tracks Quantifies Dynamic Interactions between LFA-1 and the Actin Cytoskeleton

    OpenAIRE

    Das, Raibatak; Cairo, Christopher W.; Coombs, Daniel

    2009-01-01

    The extraction of hidden information from complex trajectories is a continuing problem in single-particle and single-molecule experiments. Particle trajectories are the result of multiple phenomena, and new methods for revealing changes in molecular processes are needed. We have developed a practical technique that is capable of identifying multiple states of diffusion within experimental trajectories. We model single particle tracks for a membrane-associated protein interacting with a homoge...

  9. WE-D-BRF-01: FEATURED PRESENTATION - Investigating Particle Track Structures Using Fluorescent Nuclear Track Detectors and Monte Carlo Simulations

    International Nuclear Information System (INIS)

    Purpose: To report on the efforts funded by the AAPM seed funding grant to develop the basis for fluorescent nuclear track detector (FNTD) based radiobiological experiments in combination with dedicated Monte Carlo simulations (MCS) on the nanometer scale. Methods: Two confocal microscopes were utilized in this study. Two FNTD samples were used to find the optimal microscope settings, one FNTD irradiated with 11.1 MeV/u Gold ions and one irradiated with 428.77 MeV/u Carbon ions. The first sample provided a brightly luminescent central track while the latter is used to test the capabilities to observe secondary electrons. MCS were performed using TOPAS beta9 version, layered on top of Geant4.9.6p02. Two sets of simulations were performed, one with the Geant4-DNA physics list and approximating the FNTDs by water, a second set using the Penelope physics list in a water-approximated FNTD and a aluminum-oxide FNTD. Results: Within the first half of the funding period, we have successfully established readout capabilities of FNTDs at our institute. Due to technical limitations, our microscope setup is significantly different from the approach implemented at the DKFZ, Germany. However, we can clearly reconstruct Carbon tracks in 3D with electron track resolution of 200 nm. A second microscope with superior readout capabilities will be tested in the second half of the funding period, we expect an improvement in signal to background ratio with the same the resolution.We have successfully simulated tracks in FNTDs. The more accurate Geant4-DNA track simulations can be used to reconstruct the track energy from the size and brightness of the observed tracks. Conclusion: We have achieved the goals set in the seed funding proposal: the setup of FNTD readout and simulation capabilities. We will work on improving the readout resolution to validate our MCS track structures down to the nanometer scales

  10. Asynchronous Distributed Searchlight Scheduling

    CERN Document Server

    Obermeyer, Karl J; Bullo, Francesco

    2011-01-01

    This paper develops and compares two simple asynchronous distributed searchlight scheduling algorithms for multiple robotic agents in nonconvex polygonal environments. A searchlight is a ray emitted by an agent which cannot penetrate the boundary of the environment. A point is detected by a searchlight if and only if the point is on the ray at some instant. Targets are points which can move continuously with unbounded speed. The objective of the proposed algorithms is for the agents to coordinate the slewing (rotation about a point) of their searchlights in a distributed manner, i.e., using only local sensing and limited communication, such that any target will necessarily be detected in finite time. The first algorithm we develop, called the DOWSS (Distributed One Way Sweep Strategy), is a distributed version of a known algorithm described originally in 1990 by Sugihara et al \\cite{KS-IS-MY:90}, but it can be very slow in clearing the entire environment because only one searchlight may slew at a time. In an ...

  11. Asynchronous interactive control systems

    Science.gov (United States)

    Vuskovic, M. I.; Heer, E.

    1980-01-01

    A class of interactive control systems is derived by generalizing interactive manipulator control systems. The general structural properties of such systems are discussed and an appropriate general software implementation is proposed. This is based on the fact that tasks of interactive control systems can be represented as a network of a finite set of actions which have specific operational characteristics and specific resource requirements, and which are of limited duration. This has enabled the decomposition of the overall control algorithm into a set of subalgorithms, called subcontrollers, which can operate simultaneously and asynchronously. Coordinate transformations of sensor feedback data and actuator set-points have enabled the further simplification of the subcontrollers and have reduced their conflicting resource requirements. The modules of the decomposed control system are implemented as parallel processes with disjoint memory space communicating only by I/O. The synchronization mechanisms for dynamic resource allocation among subcontrollers and other synchronization mechanisms are also discussed in this paper. Such a software organization is suitable for the general form of multiprocessing using computer networks with distributed storage.

  12. Development of the Pattern Recognition Algorithm for Low Energy Particles in the Inner Tracking System of ALICE

    CERN Document Server

    Kolojvari, A A; CERN. Geneva; Tulina, T A

    1994-01-01

    The work is being carried out on the development of pattern recognition / initial parameters reconstruction algorithm for low energy charged particles tracks in the Inner Tracking System (ITS) of ALICE at the LHC. The algorithm should use the information only from ITS since it is supposed that it will be applied mainly to the particles which do not reach the next tracking detector, the TPC, due to their low energy and the presence of magnetic field. The algorithm is based on the transformation of any three space coordinate measurements inside the sensitive volume, placed into the solenoidal magnetic field, to the space of initial track parameters. The toy program for recognition of regular spiral trajectories is created. Some ideas are developed and tested. The further possibilities are discussed.

  13. GPU-based quasi-real-time Track Recognition in Imaging Devices: from raw Data to Particle Tracks

    CERN Document Server

    Bozza, Cristiano; De Sio, Chiara; Stellacci, Simona Maria

    2015-01-01

    Nuclear emulsions as tracking devices have been used by recent experiments thanks to fast automatic microscopes for emulsion readout. Automatic systems are evolving towards GPU-based solutions. Real-time imaging is needed to drive the motion of the microscope axes and 3D track recognition occurs quasi-online in local GPU clusters. The algorithms implemented in the Quick Scanning System are sketched. Most of them are very general and might turn out useful for other detector

  14. Increase in the area of etched alpha-particle tracks in CR-39 plastic with increasing storage time under nitrogen

    CERN Document Server

    Bhakta, J R; Miles, J C H

    1999-01-01

    The area of etched tracks in CR-39 (polyallyl diglycol carbonate, PADC) exposed to alpha-particles from an americium-241 source has been investigated as a function of post-exposure storage time in a dry nitrogen atmosphere. Data were collected over 2.5 years and the results show that the nominal maximum area of the track area distribution increases with increasing storage time.

  15. A Study Of Laser Induced Fluorescence In Neon As A Potential Particle Tracking Mechanism

    CERN Document Server

    Brookes, D J

    2000-01-01

    A new method to register the tracks of charged particles has been proposed employing laser induced fluorescence in the 1s5 - 2p9 cycling transition of neon gas as a method of determining the trajectory of a charged particle through that gas. A particle passing through neon gas will leave behind a trail of atoms trapped in the 1s5 metastable state. These metastable atoms can be made to fluoresce by pumping them to the 2p 9 state with a properly tuned laser. The 2p9 state only decays back to the 1s5 state, allowing the process to be repeated. The lifetime of the cycling transition is long enough to image when the neon atom is isolated, but collisions with other atoms can shorten this lifetime considerably. In this work the collisional deactivation rate has been measured from room temperature to the boiling point of neon. The collisional mixing rate ranged from 0.261×10- 11cm3s at 30K to 3.1×10- 11cm3s at 300K. The resulting lifetime was found to be 1130ns in 10torr of neon. The life of the neon cycling transi...

  16. Automated 3D Particle Field Extraction and Tracking System Using Digital in-line Holography

    Directory of Open Access Journals (Sweden)

    Hesham Eldeeb

    2006-01-01

    Full Text Available Digital holography for 3D particle field extraction and tracking is an active research topic. It has a great application in realizing characterization of micro-scale structures in microelectromechanical systems (MEMS with high resolution and accuracy. In-line configuration is studied in this study as the fundamental structure of a digital holography system. Digital holographic approach, not only eliminates wet chemical processing and mechanical scanning, but also enables the use of complex amplitude information inaccessible by optical reconstruction, thereby allowing flexible reconstruction algorithms to achieve optimization of specific information. However, owing to the inherently low pixel resolution of solid-state imaging sensors, digital holography gives poor depth resolution for images. This problem severely impairs the usefulness of digital holography especially in densely populated particle fields. This study describes a system that significantly improves particle axial-location accuracy by exploring the reconstructed complex amplitude information, compared with other numerical reconstruction schemes that are merely traditional optical reconstruction. Theoretical analysis and experimental results demonstrate that in-line configuration presents advantageous in enhancing the system performance. Greater flexibility of the system, higher lateral resolution and lower speckle noise can be achieved

  17. Registration of alpha particles in Makrofol-E nuclear track detectors

    Science.gov (United States)

    Rammah, Y. S.; Abdalla, Ayman M.; Ashraf, O.; Ashry, A. H.

    2016-06-01

    Fast detection of alpha particles in the range from 1 to 5 MeV in Makrofol-E polycarbonate nuclear track detectors (PCTDs) using a new chemical etchant was investigated. 252Cf and 241Am-thin open sources were used for irradiating Makrofol-E detectors with fission fragments and alpha particles in air at normal pressure and temperature (NPT). A chain of experimental work has been carried out using new etchants to register alpha particle in short time in Makrofol-E polycarbonate detectors. The etching efficiency were exhibited a clear dependence on the amount of methanol in the etching solution and etching time. The optimized chemical condition obtained at this stage of development for 200 μm Makrofol-E detectors are (8 ml of 10 N NaOH + 2 ml CH3OH) etching solutions at 60 °C for 3 h. In this study; it is possible to observe energy detection windows for Makrofol-E detectors according to applied etching duration. Makrofol-E introduced the characteristic Bragg peak, which indicates the advantages of this detector as alpha spectrometer. Consequently, the suggested new etchant can be developed for heavy ions detection and monitoring radon levels and its daughters.

  18. Particle path tracking method in two- and three-dimensional continuously rotating detonation engines

    International Nuclear Information System (INIS)

    The particle path tracking method is proposed and used in two-dimensional (2D) and three-dimensional (3D) numerical simulations of continuously rotating detonation engines (CRDEs). This method is used to analyze the combustion and expansion processes of the fresh particles, and the thermodynamic cycle process of CRDE. In a 3D CRDE flow field, as the radius of the annulus increases, the no-injection area proportion increases, the non-detonation proportion decreases, and the detonation height decreases. The flow field parameters on the 3D mid annulus are different from in the 2D flow field under the same chamber size. The non-detonation proportion in the 3D flow field is less than in the 2D flow field. In the 2D and 3D CRDE, the paths of the flow particles have only a small fluctuation in the circumferential direction. The numerical thermodynamic cycle processes are qualitatively consistent with the three ideal cycle models, and they are right in between the ideal F—J cycle and ideal ZND cycle. The net mechanical work and thermal efficiency are slightly smaller in the 2D simulation than in the 3D simulation. In the 3D CRDE, as the radius of the annulus increases, the net mechanical work is almost constant, and the thermal efficiency increases. The numerical thermal efficiencies are larger than F—J cycle, and much smaller than ZND cycle. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  19. Measurement of the track etch rates along proton and alpha particle trajectories in CR-39 and calculation of the detection efficiency

    CERN Document Server

    Dörschel, B; Hermsdorf, D; Kadner, K; Kuehne, H

    1999-01-01

    Computation of the neutron response of CR-39 detectors needs to simulate the track formation by neutron induced charged particles taking into account the bulk etch rate and the track etch rate varying along the particle trajectories. The latter one was determined experimentally by track length measurement. The results allowed to derive the relationship between the track etch rate and the restricted energy loss of the charged particles. On this basis, the geometrical track parameters and track etch rates as well as the critical angle of particle incidence could be determined for protons and alpha particles in the energy range from 0.2 to 8.8 MeV. The energy dependence of the critical angle enabled to determine the detection efficiency for a charged particle of given energy and direction.

  20. A Bayesian framework with an auxiliary particle filter for GMTI-based ground vehicle tracking aided by domain knowledge

    Science.gov (United States)

    Yu, Miao; Liu, Cunjia; Chen, Wen-hua; Chambers, Jonathon

    2014-06-01

    In this work, we propose a new ground moving target indicator (GMTI) radar based ground vehicle tracking method which exploits domain knowledge. Multiple state models are considered and a Monte-Carlo sampling based algorithm is preferred due to the manoeuvring of the ground vehicle and the non-linearity of the GMTI measurement model. Unlike the commonly used algorithms such as the interacting multiple model particle filter (IMMPF) and bootstrap multiple model particle filter (BS-MMPF), we propose a new algorithm integrating the more efficient auxiliary particle filter (APF) into a Bayesian framework. Moreover, since the movement of the ground vehicle is likely to be constrained by the road, this information is taken as the domain knowledge and applied together with the tracking algorithm for improving the tracking performance. Simulations are presented to show the advantages of both the new algorithm and incorporation of the road information by evaluating the root mean square error (RMSE).

  1. ASYNCHRONOUS ELECTRONIC DISCUSSION GROUP:

    Directory of Open Access Journals (Sweden)

    Tina Lim Swee KIM

    2007-01-01

    Full Text Available This paper examines the practice of online discussion in a course specially tailored for in-service teachers who are pursuing their basic degree qualification at a teacher training institute. Analyses of postings to the asynchronous electronic discussion group were made according to the type of postings as proposed by Poole (2000. Four focus areas were looked into, that is, content, technical, procedural, or non-academic. Analyses were done for each quarter of the 12 weeks of interaction. At the end of the learners’ participation in the EDG and before their end-of-course examination, the participants were then given a paper-based questionnaire asking their perceptions on the use of EDG as part of their coursework on the whole. Six aspects of EDG were examined, these are;Ø technical aspects, Ø motivation to use the EDG, Ø quality of interaction, Ø tutor’s response, Ø perceived learning, and Ø attitude towards EDG. Analyses on postings for the EDG showed that the bulk of the postings were made in the last quarter of the online discussions. Further, 97.8% of the postings were on content and the types of content posting registered were predominantly questions (41.19% and those that sought clarification/elaboration (37.48%. Findings from this study suggest that overall the participants were satisfied with the six aspects of EDG examined. The aspect that recorded the highest mean was ‘motivation to read tutor’s responses’ whilst the lowest mean (and the only one with negative perception was for ‘worthiness of time spent on online discussions’.

  2. Energy-efficient collaborative target tracking algorithm using cost-reference particle filtering in wireless acoustic sensor networks

    Institute of Scientific and Technical Information of China (English)

    YU Zhi-jun; WEI Jian-ming; LIU Hai-tao

    2009-01-01

    Target tracking is one of the most important applications of wireless sensor networks. Optimized computation and energy dissipation are critical requirements to save the limited resource of sensor nodes. A new robust and energy-efficient collaborative target tracking framework is proposed in this article. After a target is detected, only one active cluster is responsible for the tracking task at each time step. The tracking algorithm is distributed by passing the sensing and computation operations from one cluster to another. An event-driven cluster reforming scheme is also proposed for balancing energy consumption among nodes. Observations from three cluster members are chosen and a new class of particle filter termed cost-reference particle filter (CRPF) is introduced to estimate the target motion at the cluster head. This CRPF method is quite robust for wireless sensor network tracking applications because it drops the strong assumptions of knowing the probability distributions of the system process and observation noises. In simulation experiments, the performance of the proposed collaborative target tracking algorithm is evaluated by the metrics of tracking precision and network energy consumption.

  3. Direct measurement of particle size and 3D velocity of a gas-solid pipe flow with digital holographic particle tracking velocimetry.

    Science.gov (United States)

    Wu, Yingchun; Wu, Xuecheng; Yao, Longchao; Gréhan, Gérard; Cen, Kefa

    2015-03-20

    The 3D measurement of the particles in a gas-solid pipe flow is of great interest, but remains challenging due to curved pipe walls in various engineering applications. Because of the astigmatism induced by the pipe, concentric ellipse fringes in the hologram of spherical particles are observed in the experiments. With a theoretical analysis of the particle holography by an ABCD matrix, the in-focus particle image can be reconstructed by the modified convolution method and fractional Fourier transform. Thereafter, the particle size, 3D position, and velocity are simultaneously measured by digital holographic particle tracking velocimetry (DHPTV). The successful application of DHPTV to the particle size and 3D velocity measurement in a glass pipe's flow can facilitate its 3D diagnostics. PMID:25968543

  4. Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow.

    Science.gov (United States)

    Kim, Jin-Tae; Kim, David; Liberzon, Alex; Chamorro, Leonardo P

    2016-01-01

    3D-PTV is a quantitative flow measurement technique that aims to track the Lagrangian paths of a set of particles in three dimensions using stereoscopic recording of image sequences. The basic components, features, constraints and optimization tips of a 3D-PTV topology consisting of a high-speed camera with a four-view splitter are described and discussed in this article. The technique is applied to the intermediate flow field (5 fields around the jet core axis at a cross-plane located at ten diameters downstream of the jet is compared with literature, and the power spectrum of the large-scale streamwise velocity motions is obtained at various radial distances from the jet core. PMID:26967544

  5. Measurement of subcooled flow boiling using Particle Tracking Velocimetry and infrared thermographic technique

    International Nuclear Information System (INIS)

    Time resolved Particle Tracking Velocimetry (PTV) experiments were carried out to investigate turbulent, subcooled flow boiling through a vertical rectangular channel with a heated wall. Measurements of heated wall temperature using infrared camera were acquired. Simultaneous measurements of liquid and vapor bubbles velocity were measured using PTV. In addition, the dynamic of the bubbles were studied using Shadowgraphy technique. Turbulence statistics are inferred from PTV full-field velocity measurements. Quantities such as: instantaneous 2D velocity fields, time-averaged axial and normal velocities, axial and normal turbulence intensities, and Reynolds stresses are obtained. The present results provide new information due to the full-field nature of the technique. This work is an attempt to provide turbulent subcooled boiling flow data for validation and improvement of two phase flow computational models

  6. Development of Labview based data acquisition and multichannel analyzer software for radioactive particle tracking system

    Science.gov (United States)

    Rahman, Nur Aira Abd; Yussup, Nolida; Abdullah, Jaafar B.; Ibrahim, Maslina Bt. Mohd; Abdullah, Nor Arymaswati; Mokhtar, Mukhlis B.; Hassan, Hearie B.

    2015-04-01

    A DAQ (data acquisition) software called RPTv2.0 has been developed for Radioactive Particle Tracking System in Malaysian Nuclear Agency. RPTv2.0 that features scanning control GUI, data acquisition from 12-channel counter via RS-232 interface, and multichannel analyzer (MCA). This software is fully developed on National Instruments Labview 8.6 platform. Ludlum Model 4612 Counter is used to count the signals from the scintillation detectors while a host computer is used to send control parameters, acquire and display data, and compute results. Each detector channel consists of independent high voltage control, threshold or sensitivity value and window settings. The counter is configured with a host board and twelve slave boards. The host board collects the counts from each slave board and communicates with the computer via RS-232 data interface.

  7. Development of Labview based data acquisition and multichannel analyzer software for radioactive particle tracking system

    International Nuclear Information System (INIS)

    A DAQ (data acquisition) software called RPTv2.0 has been developed for Radioactive Particle Tracking System in Malaysian Nuclear Agency. RPTv2.0 that features scanning control GUI, data acquisition from 12-channel counter via RS-232 interface, and multichannel analyzer (MCA). This software is fully developed on National Instruments Labview 8.6 platform. Ludlum Model 4612 Counter is used to count the signals from the scintillation detectors while a host computer is used to send control parameters, acquire and display data, and compute results. Each detector channel consists of independent high voltage control, threshold or sensitivity value and window settings. The counter is configured with a host board and twelve slave boards. The host board collects the counts from each slave board and communicates with the computer via RS-232 data interface

  8. Mechanical engineering and design of silicon-based particle tracking devices

    International Nuclear Information System (INIS)

    The Mechanical Engineering and Electronics Division of the Los Alamos National Laboratory has been investigating silicon-based particle tracking device technology as part of the Superconducting Super Collider-sponsored silicon subsystem collaboration. Structural, thermal, and materials issues have been addressed. This paper discussed detector structural integrity and stability, including detailed finite element models of the silicon chip support and predictive methods used in designing with advanced composite materials. Electronic thermal loading and efficient dissipation of such energy using heat pipe technology has been investigated. The use of materials whose coefficients of thermal expansion are engineered to match silicon or to be near zero, as appropriate, have been explored. Material analysis and test results from radiation, chemical, and static loading are compared with analytical predictions and discussed. 1 ref., 2 figs., 1 tab

  9. SPACE CHARGE SIMULATION METHODS INCORPORATED IN SOME MULTI - PARTICLE TRACKING CODES AND THEIR RESULTS COMPARISON.

    Energy Technology Data Exchange (ETDEWEB)

    BEEBE - WANG,J.; LUCCIO,A.U.; D IMPERIO,N.; MACHIDA,S.

    2002-06-03

    Space charge in high intensity beams is an important issue in accelerator physics. Due to the complicity of the problems, the most effective way of investigating its effect is by computer simulations. In the resent years, many space charge simulation methods have been developed and incorporated in various 2D or 3D multi-particle-tracking codes. It has becoming necessary to benchmark these methods against each other, and against experimental results. As a part of global effort, we present our initial comparison of the space charge methods incorporated in simulation codes ORBIT++, ORBIT and SIMPSONS. In this paper, the methods included in these codes are overviewed. The simulation results are presented and compared. Finally, from this study, the advantages and disadvantages of each method are discussed.

  10. Expert (exotic Particle Emission and Radioactivity by Tracking) Studies at the Super-Frs Spectrometer

    Science.gov (United States)

    Geissel, H.; Kiselev, O.; Mukha, I.; Simon, H.; Scheidenberger, C.; Weick, H.; Winkler, M.; Fomichev, A.; Belogurov, S.; Bezbakh, A.; Chudoba, V.; Golovkov, M.; Gorshkov, A.; Itkis, Y.; Kaminski, G.; Knyazev, A.; Knyazheva, G.; Kozulin, E.; Krupko, S.; Mianowski, S.; Rymzhanova, S.; Sidorchuk, S.; Sharov, P.; Slepnev, R.; Ter-Akopian, G.; Zagrebaev, V.; Pfützner, M.; Dominik, W.; Janas, Z.; Mazzocchi, Ch.; Mianowski, S.; Korsheninnikov, A. A.; Kuzmin, E. A.; Nikolskii, E. Yu.; Eremin, I.; Eremin, V.; Fadeeva, N.; Terukov, E.; Tuboltsev, Yu.; Verbitskaya, E.; Ershov, S. N.; Egorova, I. A.; Nasirov, A. K.; Dunin, V. B.; Alkhazov, G. D.; Dobrovolsky, A. V.; Khanzadeev, A. V.; Parfenova, Yu. L.; Xu, X.; Kaminski, G.; Kopatch, Y.

    2015-06-01

    The proposal EXPERT is suggested for the Super-FRS Collaboration physics program [1] in the NUSTAR Collaboration of the project FAIR (Facility for Antiproton and Ion Research) in Darmstadt, Germany. It is aimed at studies of the nuclear landscape beyond the proton and neutron drip-lines and intends to push researches up to limits of nuclear existence. By combining the EXPERT instrumentation (two tracking techniques applied for radioactivity and nuclear decays in-flight), the phenomena of multi-nucleon radioactivity, resonance decays in continuum, beta-delayed exotic decays and exotic excitation modes can be studied via observations of particle emissions, including the 2p, 4p, 6p, n, 2n, 4n, 6n channels.

  11. Are particle-tracking algorithms the adequate method to determine migration paths for performance assessment

    International Nuclear Information System (INIS)

    Nuclear waste repositories have to be constructed in such a way that no hazardous effects on the environment do occur even after closure of the facility. To show compliance with this requirement longterm safety assessments simulate potential releases of radionuclides from the repository, their migration through the geosphere and their potential hazards in the biosphere. An integral part of these simulations is the calculation of groundwater flow and nuclide transport in the rocks surrounding the repository. Since transport calculations require great computational efforts these should be restricted to the regions of interest. These are usually derived from the groundwater flow models by means of particle-tracking algorithms. However, these do not necessarily represent the fastest travel path to the environment. Therefore one has to be aware of the limitations of pathlines for use in longterm safety assessments. Computer codes used: NAMMU. 6 figs., 3 refs

  12. Development of Labview based data acquisition and multichannel analyzer software for radioactive particle tracking system

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Nur Aira Abd, E-mail: nur-aira@nuclearmalaysia.gov.my; Yussup, Nolida; Ibrahim, Maslina Bt. Mohd; Abdullah, Nor Arymaswati; Mokhtar, Mukhlis B. [Technical Support Division, Malaysian Nuclear Agency, 43000, Kajang, Selangor (Malaysia); Abdullah, Jaafar B.; Hassan, Hearie B. [Industrial Technology Division, Malaysian Nuclear Agency, 43000, Kajang, Selangor (Malaysia)

    2015-04-29

    A DAQ (data acquisition) software called RPTv2.0 has been developed for Radioactive Particle Tracking System in Malaysian Nuclear Agency. RPTv2.0 that features scanning control GUI, data acquisition from 12-channel counter via RS-232 interface, and multichannel analyzer (MCA). This software is fully developed on National Instruments Labview 8.6 platform. Ludlum Model 4612 Counter is used to count the signals from the scintillation detectors while a host computer is used to send control parameters, acquire and display data, and compute results. Each detector channel consists of independent high voltage control, threshold or sensitivity value and window settings. The counter is configured with a host board and twelve slave boards. The host board collects the counts from each slave board and communicates with the computer via RS-232 data interface.

  13. Behaviour of interatomic interaction potentials in metal in the track area of heavy charged particles

    International Nuclear Information System (INIS)

    The computational technique of interatomic interaction potentials in the presence of ionized states is developed. Using aluminium as an example, they are obtained for atoms with different ionization degree. The molecular-dynamic modeling of atom transfer in crystal lattice has shown that ion emission from fast charged particle track near surface (coulomb explosion) is possible if the life time of ionized states is 10-13 s or more. On the base of pseudopotential approach behaviour of interaction potentials in conditions of electron subsystem excitation is analyzed. It has been found out that thermal tailing of Fermi surface does not result in essential change of interatomic interaction forces, and the local increase of conduction electrons concentration induces softening of crystal lattice when configuration with lesser interatomic distance becomes equilibrium

  14. Irreproducibility of Diffusion Coefficients in Single-Particle-Tracking Measurements in Heterogeneous Environment

    CERN Document Server

    Akimoto, Takuma

    2016-01-01

    Local diffusion coefficients in living cells are highly heterogeneous and may change over time. Such a time-dependent and spatially heterogeneous environment results in irreproducibility of single-particle-tracking measurements. Here, we provide rigorous descriptions of equilibrium and non-equilibrium diffusion processes for a heterogeneous diffusion model in living cells. We give exact solutions for the mean square displacement (MSD) and the relative standard deviation of the time-averaged MSD for equilibrium and non-equilibrium situations. We find that the time-averaged MSD grows linearly with time and that the diffusion coefficients are intrinsically random in non-equilibrium situations. Our findings pave the way for a theoretical understanding of irreproducible diffusion coefficients in cell biology.

  15. Characterization of hydrogel microstructure using laser tweezers particle tracking and confocal reflection imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kotlarchyk, M A; Botvinick, E L; Putnam, A J, E-mail: elliot.botvinick@uci.ed, E-mail: putnam@umich.ed [Department of Biomedical Engineering, University of California, Irvine, CA (United States)

    2010-05-19

    Hydrogels are commonly used as extracellular matrix mimetics for applications in tissue engineering and increasingly as cell culture platforms with which to study the influence of biophysical and biochemical cues on cell function in 3D. In recent years, a significant number of studies have focused on linking substrate mechanical properties to cell function using standard methodologies to characterize the bulk mechanical properties of the hydrogel substrates. However, current understanding of the correlations between the microstructural mechanical properties of hydrogels and cell function in 3D is poor, in part because of a lack of appropriate techniques. Here we have utilized a laser tracking system, based on passive optical microrheology instrumentation, to characterize the microstructure of viscoelastic fibrin clots. Trajectories and mean square displacements were observed as bioinert PEGylated (PEG: polyethylene glycol) microspheres (1, 2 or 4.7 {mu}m in diameter) diffused within confined pores created by the protein phase of fibrin hydrogels. Complementary confocal reflection imaging revealed microstructures comprised of a highly heterogeneous fibrin network with a wide range of pore sizes. As the protein concentration of fibrin gels was increased, our quantitative laser tracking measurements showed a corresponding decrease in particle mean square displacements with greater resolution and sensitivity than conventional imaging techniques. This platform-independent method will enable a more complete understanding of how changes in substrate mechanical properties simultaneously influence other microenvironmental parameters in 3D cultures.

  16. High-LET dose-response characteristics by track structure theory of heavy charged particles

    International Nuclear Information System (INIS)

    The track structure theory developed by Katz and co-workers ascribes the effect of high-LET radiation to the highly inhomogeneous dose distribution due to low energy Δ-rays ejected from the particle track. The theory predicts the effectiveness of high-LET radiation by using the ion parameters zsub(eff') effective charge of the ion, and β = v/c, the relative ion velocity, together with the characteristic dose D37 derived from low-LET dose-response characteristic of the detector and the approximate size asub(0) of the sensitive element of the detector. 60Co gamma-irradiation is used as a reference low-LET radiation, while high-LET radiation ranging from 16 MeV protons to 4 MeV/amu 160-ions covering an initial LET range of 30-5500 MeVcm2/g is obtained from a tandem Van de Graaff accelerator. A thin film (5mg/cm2) radiochromic dye cyanide plastic dosemeter was used as detector with the characteristic dose of 16.8 Mrad and a sensitive element size of 10-7 cm. Theoretical and experimental effectiveness, RBE, agreed within 10 to 25% depending on LET. (author)

  17. Fabrication of bright and small size semiconducting polymer nanoparticles for cellular labelling and single particle tracking

    Science.gov (United States)

    Wei, Lin; Zhou, Peng; Yang, Qingxiu; Yang, Qiaoyu; Ma, Ming; Chen, Bo; Xiao, Lehui

    2014-09-01

    In this work, we demonstrate a convenient and robust strategy for efficient fabrication of high fluorescence quantum yield (QY, 49.8 +/- 3%) semiconducting polymer nanoparticles (SPNs), with size comparable with semiconductor quantum dots (Qdots). The SPNs were synthesized by co-precipitation of hydrophobic semiconducting polymer together with amphiphilic multidentate polymer. Comprehensive spectroscopic and microscopic characterizations showed that the SPNs possess superior photophysical performance, with excellent fluorescence brightness and reduced photoblinking in contrast with Qdots, as well as good photostability compared to a fluorescent protein of a similar size, phycoerythrin. More importantly, by conjugating membrane biomarkers onto the surface of SPNs, it was found that they were not only suitable for specific cellular labelling but also for single particle tracking because of the improved optical performance.In this work, we demonstrate a convenient and robust strategy for efficient fabrication of high fluorescence quantum yield (QY, 49.8 +/- 3%) semiconducting polymer nanoparticles (SPNs), with size comparable with semiconductor quantum dots (Qdots). The SPNs were synthesized by co-precipitation of hydrophobic semiconducting polymer together with amphiphilic multidentate polymer. Comprehensive spectroscopic and microscopic characterizations showed that the SPNs possess superior photophysical performance, with excellent fluorescence brightness and reduced photoblinking in contrast with Qdots, as well as good photostability compared to a fluorescent protein of a similar size, phycoerythrin. More importantly, by conjugating membrane biomarkers onto the surface of SPNs, it was found that they were not only suitable for specific cellular labelling but also for single particle tracking because of the improved optical performance. Electronic supplementary information (ESI) available: Experimental section and additional supporting results as noted in the text

  18. Improvements on Particle Tracking Velocimetry: model-free calibration and noiseless measurement of second order statistics of the velocity field

    CERN Document Server

    Machicoane, Nathanael; Bourgoin, Mickael; Aliseda, Alberto; Volk, Romain

    2016-01-01

    This article describes two independent developments aimed at improving the Particle Tracking Method for measurements of flow or particle velocities. First, a stereoscopic multicamera calibration method that does not require any optical model is described and evaluated. We show that this new calibration method gives better results than the most commonly-used technique, based on the Tsai camera/optics model. Additionally, the methods uses a simple interpolant to compute the transformation matrix and it is trivial to apply for any experimental fluid dynamics visualization set up. The second contribution proposes a solution to remove noise from Eulerian measurements of velocity statistics obtained from Particle Tracking velocimetry, without the need of filtering and/or windowing. The novel method presented here is based on recomputing particle displacement measurements from two consecutive frames for multiple different time-step values between frames. We show the successful application of this new technique to re...

  19. Single particle tracking in systems showing anomalous diffusion: the role of weak ergodicity breaking.

    Science.gov (United States)

    Burov, Stas; Jeon, Jae-Hyung; Metzler, Ralf; Barkai, Eli

    2011-02-01

    Anomalous diffusion has been widely observed by single particle tracking microscopy in complex systems such as biological cells. The resulting time series are usually evaluated in terms of time averages. Often anomalous diffusion is connected with non-ergodic behaviour. In such cases the time averages remain random variables and hence irreproducible. Here we present a detailed analysis of the time averaged mean squared displacement for systems governed by anomalous diffusion, considering both unconfined and restricted (corralled) motion. We discuss the behaviour of the time averaged mean squared displacement for two prominent stochastic processes, namely, continuous time random walks and fractional Brownian motion. We also study the distribution of the time averaged mean squared displacement around its ensemble mean, and show that this distribution preserves typical process characteristics even for short time series. Recently, velocity correlation functions were suggested to distinguish between these processes. We here present analytical expressions for the velocity correlation functions. The knowledge of the results presented here is expected to be relevant for the correct interpretation of single particle trajectory data in complex systems. PMID:21203639

  20. Olivine in terminal particles of Stardust aerogel tracks and analogous grains in chondrite matrix

    Science.gov (United States)

    Frank, David R.; Zolensky, Michael E.; Le, Loan

    2014-10-01

    The dearth of both major and minor element analyses of anhydrous silicate phases in chondrite matrix has thus far hindered their comparison to the Wild 2 samples. We present 68 analyses of olivine (Fa0-97) in the coarse-grained terminal particles of Stardust aerogel tracks and a comprehensive dataset (>103 analyses) of analogous olivine grains (5-30 μm) isolated in CI, CM, CR, CH, CO, CV3-oxidized, CV3-reduced, C3-ungrouped (Acfer 094 and Ningqiang), L/LL 3.0-4, EH3, and Kakangari chondrite matrix. These compositions reveal that Wild 2 likely accreted a diverse assortment of material that was radially transported from various carbonaceous and ordinary chondrite-forming regions. The Wild 2 olivine includes amoeboid olivine aggregates (AOAs), refractory forsterite, type I and type II chondrule fragments and/or microchondrules, and rare relict grain compositions. In addition, we have identified one terminal particle that has no known compositional analog in the meteorite record and may be a signature of low-temperature, aqueous processing in the Kuiper Belt. The generally low Cr content of FeO-rich olivine in the Stardust samples indicates that they underwent mild thermal metamorphism, akin to a petrologic grade of 3.05-3.15.

  1. Particle tracking via RFID technology to monitor bedload sediment dynamics in mountain streams

    Science.gov (United States)

    Toro, Matteo; Fraccarollo, Luigi; Corbo, Simona; Maggioni, Alberto; Brardinoni, Francesco

    2015-04-01

    In this contribution we present preliminary results on the monitoring of bedload entrainment and transport in two mountain streams, the Grigno Creek (90 km2) and its tributary, the Tolvà Creek (14 km2), located in Valsugana, Autonomous Province of Trento. In particular, we monitor bedload by means of Radio Frequency Identification (RFID) technology in conjunction with Passive Integrated Transponders (PIT) (e.g., Lamarre et al., 2005) injected into pebble-to-cobble sized tracer stones (b-axis ranging from 30 to 130 mm). In the Grigno Creek 120 PITs were released in December 2013 along a 100-m channel reach and have been surveyed 10 times. In the Tolvà Creek 100 PITs were released in July 2013 along a 100-m channel reach, and the site has been surveyed 4 times. Particle tracking is conducted by integrating two complementary antenna types: (i) a portable one, which enables to estimate travel distances of tagged clasts; and (ii) a set of four fixed antennas (25m apart from each other), which allows detecting motion/rest periods of particles, entrainment thresholds and transport velocities. Particle tracking is combined with on-site high-frequency (i.e., 10 minutes) water stage monitoring. Salt dilution method is monthly applied to relate flow discharge to water stage. The analyzed river reaches extend over different morphologic units (steps, pools, glides and boulder-cascades). We are looking to estimate (i) the channel forming discharge; (ii) a quantitative evaluation of specific bedload transport. These information will be associated to the surficial bed texture and bed morphology. Data collected from fixed and mobile antennas will enable to infer statistical information of the trajectories run by tracer ensemble, in particular the step lengths, the total travel distances and the rest periods. Lamarre H., MacVicar B., Roy A.G. 2005 Using Passive Integrated Transponder (PIT) tags to investigate sediment transport in gravel-bed rivers. Journal of Sedimentary Research

  2. Dependence of alpha particle track diameter on the free volume holes size using positron annihilation lifetime technique

    Energy Technology Data Exchange (ETDEWEB)

    El-Gamal, S. [Physics Department, Faculty of Education, Ain Shams University, Roxy, 11711 Cairo (Egypt); Abdalla, Ayman M., E-mail: aymanabdalla62@hotmail.com [Physics Department, Faculty of Arts and Sciences, Najran University, Najran (Saudi Arabia); Centre for Advanced Materials and Nano-Engineering, Najran University, Najran 11001 (Saudi Arabia); Abdel-Hady, E.E. [Physics Department, Faculty of Science, Minia University, BO 61519, Minia (Egypt)

    2015-09-15

    The alpha particle track diameter dependence of the free volume holes size (V{sub f}) in DAM–ADC and CR-39 nuclear track detectors was investigated using positron annihilation lifetime technique. The effect of temperature on the alpha particle track diameter and free volume were also investigated in the T-range (RT-130 °C). The obtained results revealed that the values of ortho-positronium lifetime τ{sub 3} and V{sub f} increases while I{sub 3} slightly increases as T increases for the two detectors. The values of τ{sub 3}, V{sub f} and I{sub 3} are higher in CR-39 than DAM–ADC. The interpretation of obtained results is based on the fact that increasing T leads to significant enhancement of thermal expansion of the polymer matrix and consequently V{sub f} increases. The track diameter increases as T increases. This can be explained by the fact that the increase in T increases the crystal size and V{sub f} in the polymer. A relationship between V{sub f} and the alpha particle track diameter was obtained. Moreover results of detector irradiation, along with free volume evaluation are addressed and thoroughly discussed.

  3. Dependence of alpha particle track diameter on the free volume holes size using positron annihilation lifetime technique

    International Nuclear Information System (INIS)

    The alpha particle track diameter dependence of the free volume holes size (Vf) in DAM–ADC and CR-39 nuclear track detectors was investigated using positron annihilation lifetime technique. The effect of temperature on the alpha particle track diameter and free volume were also investigated in the T-range (RT-130 °C). The obtained results revealed that the values of ortho-positronium lifetime τ3 and Vf increases while I3 slightly increases as T increases for the two detectors. The values of τ3, Vf and I3 are higher in CR-39 than DAM–ADC. The interpretation of obtained results is based on the fact that increasing T leads to significant enhancement of thermal expansion of the polymer matrix and consequently Vf increases. The track diameter increases as T increases. This can be explained by the fact that the increase in T increases the crystal size and Vf in the polymer. A relationship between Vf and the alpha particle track diameter was obtained. Moreover results of detector irradiation, along with free volume evaluation are addressed and thoroughly discussed

  4. Quantifying the dynamic transition of hydrogenated castor oil gels measured via multiple particle tracking microrheology.

    Science.gov (United States)

    Wehrman, Matthew D; Lindberg, Seth; Schultz, Kelly M

    2016-08-14

    Rheological modifiers are essential ingredients in commercial materials that exploit facile and repeatable phase transitions. Although rheological modifiers are used to change flow behavior or quiescent stability, the complex properties of particulate gels during dilution is not well studied. We characterize a dynamically evolving colloidal gel, hydrogenated castor oil (HCO), a naturally sourced material, used in consumer products. This HCO scaffold consists of fibrous colloids, a surfactant (linear alkylbenzene sulfonate) and water. The gel undergoes critical transitions, degradation and formation, in response to an osmotic pressure gradient. Multiple particle tracking microrheology (MPT) measures the evolving material properties. In MPT, fluorescent probe particles are embedded into the sample and Brownian motion is measured. MPT data are analyzed using time-cure superposition, identifying critical transition times and critical relaxation exponents for degradation and formation where tc,deg = 102.5 min, ndeg = 0.77 ± 0.09, tc,for = 31.9 min, and nfor = 0.94 ± 0.11, respectively. During degradation and formation HCO gels evolve heterogeneously, this heterogeneity is characterized spatially and temporally. Heterogeneity of the gel is quantified by comparing variances of single particle van Hove correlation functions using an F-test with a 95% confidence interval. HCO transitions have rheological heterogeneous microenvironments that are homogeneously distributed throughout the field of view. Although HCO gels do evolve heterogeneously, this work determines that these heterogeneities do not significantly change traditional MPT measurements but the analysis techniques developed provide additional information on the unique heterogeneous scaffold microenvironments. This creates a toolbox that can be widely applied to other scaffolds during dynamic transitions. PMID:27396611

  5. A flame particle tracking analysis of turbulence–chemistry interaction in hydrogen–air premixed flames

    KAUST Repository

    Uranakara, Harshavardhana A.

    2015-11-21

    Interactions of turbulence, molecular transport, and energy transport, coupled with chemistry play a crucial role in the evolution of flame surface geometry, propagation, annihilation, and local extinction/re-ignition characteristics of intensely turbulent premixed flames. This study seeks to understand how these interactions affect flame surface annihilation of lean hydrogen–air premixed turbulent flames. Direct numerical simulations (DNSs) are conducted at different parametric conditions with a detailed reaction mechanism and transport properties for hydrogen–air flames. Flame particle tracking (FPT) technique is used to follow specific flame surface segments. An analytical expression for the local displacement flame speed (Sd) of a temperature isosurface is considered, and the contributions of transport, chemistry, and kinematics on the displacement flame speed at different turbulence-flame interaction conditions are identified. In general, the displacement flame speed for the flame particles is found to increase with time for all conditions considered. This is because, eventually all flame surfaces and their resident flame particles approach annihilation by reactant island formation at the end of stretching and folding processes induced by turbulence. Statistics of principal curvature evolving in time, obtained using FPT, suggest that these islands are ellipsoidal on average enclosing fresh reactants. Further examinations show that the increase in Sd is caused by the increased negative curvature of the flame surface and eventual homogenization of temperature gradients as these reactant islands shrink due to flame propagation and turbulent mixing. Finally, the evolution of the normalized, averaged, displacement flame speed vs. stretch Karlovitz number are found to collapse on a narrow band, suggesting that a unified description of flame speed dependence on stretch rate may be possible in the Lagrangian description.

  6. Target Tracking Approximation Algorithms with Particle Filter Optimization and Fault-Tolerant Analysis in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Xiang Gao

    2012-05-01

    Full Text Available In order to process target tracking approximation with unknown motion state models beforehand in a two-dimensional field of binary proximity sensors, the algorithms based on cost functions of particle filters and near-linear curve simple optimization are proposed in this paper. Through moving target across detecting intersecting fields of sensor nodes sequentially, cost functions are introduced to solve target tracking approximation and velocity estimation which is not similar to traditional particle filters that rely on probabilistic assumptions about the motion states. Then a near-linear curve geometric approach is used to simplify and easily describe target trajectories that are below a certain error measure. Because there maybe some sensor nodes invalid in practice, so a fault-tolerant detection is applied to avoid the nodes’ reporting fault and also improve accuracy of tracking at the same time. The validity of our algorithms is demonstrated through simulation results.

  7. Lagrangian 3D particle tracking in high-speed flows: Shake-The-Box for multi-pulse systems

    Science.gov (United States)

    Novara, Matteo; Schanz, Daniel; Reuther, Nico; Kähler, Christian J.; Schröder, Andreas

    2016-08-01

    The Shake-The-Box (STB) particle tracking technique, recently introduced for time-resolved 3D particle image velocimetry (PIV) images, is applied here to data from a multi-pulse investigation of a turbulent boundary layer flow with adverse pressure gradient in air at 36 m/s ( Re τ = 10,650). The multi-pulse acquisition strategy allows for the recording of four-pulse long time-resolved sequences with a time separation of a few microseconds. The experimental setup consists of a dual-imaging system and a dual-double-cavity laser emitting orthogonal polarization directions to separate the four pulses. The STB particle triangulation and tracking strategy is adapted here to cope with the limited amount of realizations available along the time sequence and to take advantage of the ghost track reduction offered by the use of two independent imaging systems. Furthermore, a correction scheme to compensate for camera vibrations is discussed, together with a method to accurately identify the position of the wall within the measurement domain. Results show that approximately 80,000 tracks can be instantaneously reconstructed within the measurement volume, enabling the evaluation of both dense velocity fields, suitable for spatial gradients evaluation, and highly spatially resolved boundary layer profiles. Turbulent boundary layer profiles obtained from ensemble averaging of the STB tracks are compared to results from 2D-PIV and long-range micro particle tracking velocimetry; the comparison shows the capability of the STB approach in delivering accurate results across a wide range of scales.

  8. Behavioral synthesis of asynchronous circuits

    DEFF Research Database (Denmark)

    Nielsen, Sune Fallgaard

    2005-01-01

    domain by introducing a computation model, which resembles the synchronous datapath and control architecture, but which is completely asynchronous. The model contains the possibility for isolating some or all of the functional units by locking their respective inputs and outputs while the functional unit...

  9. Acquiring Knowledge from Asynchronous Discussion

    Science.gov (United States)

    Teo, Yiong Hwee; Webster, Len

    2008-01-01

    This article discusses a study which was designed to explore how online scaffolding can be incorporated to support knowledge acquisition in asynchronous discussion. A group of Singapore preservice teachers engaged in collaborative critiquing of videos before they embarked on their video projects to illustrate what constitutes good and bad video…

  10. Asynchronous sequential machine design and analysis

    CERN Document Server

    Tinder, Richard

    2009-01-01

    Asynchronous Sequential Machine Design and Analysis provides a lucid, in-depth treatment of asynchronous state machine design and analysis presented in two parts: Part I on the background fundamentals related to asynchronous sequential logic circuits generally, and Part II on self-timed systems, high-performance asynchronous programmable sequencers, and arbiters.Part I provides a detailed review of the background fundamentals for the design and analysis of asynchronous finite state machines (FSMs). Included are the basic models, use of fully documented state diagrams, and the design and charac

  11. Instantaneous axial velocity of a radioactive tracer determined with radioactive particle tracking

    International Nuclear Information System (INIS)

    Radioactive Particle Tracking (RPT) is a technique that has been successfully used to get features of the liquid and/or the solid motion in multiphase contactors. It is one of the rare techniques able to provide experimental data in dense and strongly turbulent multiphase media. Validation of the technique has always been based on comparing the estimated mean velocity to an imposed mean velocity although the extracted features are frequently related to the instantaneous velocities. The present work pursues the analysis, through calibration experiments, of the ability of RPT to get the actual tracer instantaneous velocities. With this purpose, the motion of a radioactive tracer attached to a moving rod driven by a pneumatic system is reconstructed from the combined response of an array of 10 NaI(Tl) scintillation detectors. Simultaneously, the tracer motion is registered through an encoder able to establish the axial tracer coordinate with high precision and high time resolution. The tracer is a gold particle, activated by neutron bombardment. The rod is moved at different velocities and it travels upwards and downwards close to the column centre. A mini-pilot scale bubble column is used as the test facility. The model liquid is tap water in batch mode and the gas is air, flowing at different gas velocities, spanning the homogeneous and the heterogeneous flow regimes. Time series of the entirety response of all the detectors, while the rod is moving at different imposed velocities within the two phase emulsion, are measured with a sampling period of 0.03 s during about 2 minutes. The instantaneous tracer positions and velocities reconstructed from RPT and the one obtained from the encoder response are compared under different operating conditions and for different tracer velocities. (author)

  12. A shallow water equation solver and particle tracking method to evaluate the debris transport

    International Nuclear Information System (INIS)

    Debris generated by loss-of-coolant accident (LOCA) may run all over the containment floor, block the sump screen (or strainer), increase the hydraulic head loss across the screen, and eventually, have an adverse effect to long term recirculation cooling operation in pressurized water reactor (PWR). To resolve the problem from the issue, the replacement of containment recirculation sump strainer is being performed for the most of operating nuclear power plants (NPP) having limited strainer areas. The screen area required to incorporate the potential debris loading has been determined using the transport fraction (TF) defined by a ratio of amount of debris accumulated on screen to one generated by LOCA. For the most conventional NPP, the debris transport to the sump screen is initiated by the recirculation actuation. Therefore, evaluation of TF was based on the separated analyses on how the debris generated by LOCA is distributed to the containment floor before recirculation and on how much debris is transported by the flow in the containment pool after recirculation, respectively. This led to an approach to obtain TF values for blowdown phase, wash-down phase, pool recirculation phase, separately. Especially, the TF during recirculation phase has been calculated by steady state CFD analysis based that the break flow and recirculation safety injection flow are balanced, thus steady state flow field over the containment is established. However, such a phase separation cannot be applied to some NPP like the Advanced Power Reactor 1400 (APR1400) having no recirculation operation. Transport of debris to sump in the APR1400 is initiated from the early phase of a LOCA in fully transient manner. The present study is to calculate debris transport on the containment floor to sump in APR1400. For this purpose, a hydraulic model to calculate the transient flow field and a particle tracking model to trace the debris particle within the calculation domain are discussed

  13. Single molecule λ-DNA stretching studied by microfluidics and single particle tracking

    Science.gov (United States)

    Wang, Jun; Lu, Chang

    2007-10-01

    DNA stretching has been an intensively studied topic due to its involvement in the cellular functions. In this work, we studied DNA stretching based on microfluidics and single particle tracking techniques. Microfluidics generates well-defined flow field within microscale channels and potentially allows the incorporation of chemical and biological assays with the single molecule experiments. Single DNA molecules were tethered to the channel bottom (glass) at one end and to fluorescent microbeads at the other end. The microscale flow exerted hydrodynamic force on the microbead with a magnitude dependent on the flow rate. The force-extension curves of the single DNA molecules were obtained by localizing the fluorescent microbead with nanometer precision at different flow rates. We were able to obtain DNA force-extension curves which fit the wormlike chain model very well. Furthermore, we also observed plateaus at low forces (15-30pN) in these curves when the hydrodynamic force was kept constant for a duration of 10s at each flow rate. One possible reason is that stretching force with long duration lowers the activation barrier for the conformational changes of a double-stranded DNA molecule. We expect that this approach will be useful for studying the force associated with biological events involving single DNA molecules in general.

  14. Study of contrail microphysics in the vortex phase with a Lagrangian particle tracking model

    Directory of Open Access Journals (Sweden)

    S. Unterstrasser

    2010-06-01

    Full Text Available Crystal sublimation/loss is a~dominant feature of the contrail evolution during the vortex phase and has a substantial impact on the later contrail-to-cirrus transition. Previous studies showed that the fraction of crystals surviving the vortex phase depends primarily on relative humidity, temperature and the aircraft type. An existing model for contrail vortex phase simulations (with a 2–moment bulk microphysics scheme was upgraded with a newly developed state-of-the-art microphysics module (LCM which uses Lagrangian particle tracking. This allows for explicit process-oriented modelling of the ice crystal size distribution in contrast to the bulk approach. We show that it is of great importance to employ an advanced microphysics scheme to determine the crystal loss during the vortex phase. The LCM-model shows even larger sensitivities to the above mentioned key parameters than previously estimated with the bulk model. The impact of the initial crystal number is studied and for the first time also the initial width of the crystal size distribution. Both are shown to be relevant. This corroborates the need for a realistic representation of microphysical processes and knowledge of the ice phase characteristics.

  15. Study of contrail microphysics in the vortex phase with a Lagrangian particle tracking model

    Directory of Open Access Journals (Sweden)

    S. Unterstrasser

    2010-10-01

    Full Text Available Crystal sublimation/loss is a dominant feature of the contrail evolution during the vortex phase and has a substantial impact on the later contrail-to-cirrus transition. Previous studies showed that the fraction of crystals surviving the vortex phase depends primarily on relative humidity, temperature and the aircraft type. An existing model for contrail vortex phase simulations (with a 2-moment bulk microphysics scheme was upgraded with a newly developed state-of-the-art microphysics module (LCM which uses Lagrangian particle tracking. This allows for explicit process-oriented modelling of the ice crystal size distribution in contrast to the bulk approach. We show that it is of great importance to employ an advanced microphysics scheme to determine the crystal loss during the vortex phase. The LCM-model shows even larger sensitivities to the above mentioned key parameters than previously estimated with the bulk model. The impact of the initial crystal number is studied and for the first time also the initial width of the crystal size distribution. Both are shown to be relevant. This corroborates the need for a realistic representation of microphysical processes and knowledge of the ice phase characteristics.

  16. A review of progress in single particle tracking: from methods to biophysical insights

    Science.gov (United States)

    Manzo, Carlo; Garcia-Parajo, Maria F.

    2015-12-01

    Optical microscopy has for centuries been a key tool to study living cells with minimum invasiveness. The advent of single molecule techniques over the past two decades has revolutionized the field of cell biology by providing a more quantitative picture of the complex and highly dynamic organization of living systems. Amongst these techniques, single particle tracking (SPT) has emerged as a powerful approach to study a variety of dynamic processes in life sciences. SPT provides access to single molecule behavior in the natural context of living cells, thereby allowing a complete statistical characterization of the system under study. In this review we describe the foundations of SPT together with novel optical implementations that nowadays allow the investigation of single molecule dynamic events with increasingly high spatiotemporal resolution using molecular densities closer to physiological expression levels. We outline some of the algorithms for the faithful reconstruction of SPT trajectories as well as data analysis, and highlight biological examples where the technique has provided novel insights into the role of diffusion regulating cellular function. The last part of the review concentrates on different theoretical models that describe anomalous transport behavior and ergodicity breaking observed from SPT studies in living cells.

  17. Uncovering homo-and hetero-interactions on the cell membrane using single particle tracking approaches

    Science.gov (United States)

    Torreno-Pina, Juan A.; Manzo, Carlo; Garcia-Parajo, Maria F.

    2016-03-01

    The plasma membrane of eukaryotic cells is responsible for a myriad of functions that regulate cell physiology and plays a crucial role in a multitude of processes that include adhesion, migration, signaling recognition and cell-cell communication. This is accomplished by specific interactions between different membrane components such as lipids and proteins on the lipid bilayer but also through interactions with the underlying cortical actin cytoskeleton on the intracellular side and the glycocalyx matrix in close proximity to the extracellular side. Advanced biophysical techniques, including single particle tracking (SPT) have revealed that the lateral diffusion of molecular components on the plasma membrane represents a landmark manifestation of such interactions. Indeed, by studying changes in the diffusivity of individual membrane molecules, including sub-diffusion, confined diffusion and/or transient arrest of molecules in membrane compartments, it has been possible to gain insight on the nature of molecular interactions and to infer on its functional role for cell response. In this review, we will revise some exciting results where SPT has been crucial to reveal homo- and hetero-interactions on the cell membrane.

  18. Measuring the viscous and elastic properties of single cells using video particle tracking microrheology

    CERN Document Server

    Warren, Rebecca Louisa; Li, Xiang; Glidle, Andrew; Carlsson, Allan; Cooper, Jonathan M

    2011-01-01

    We present a simple and \\emph{non-invasive} experimental procedure to measure the linear viscoelastic properties of cells by passive video particle tracking microrheology. In order to do this, a generalised Langevin equation is adopted to relate the time-dependent thermal fluctuations of a bead, chemically bound to the cell's \\emph{exterior}, to the frequency-dependent viscoelastic moduli of the cell. It is shown that these moduli are related to the cell's cytoskeletal structure, which in this work is changed by varying the solution osmolarity from iso- to hypo-osmotic conditions. At high frequencies, the viscoelastic moduli frequency dependence changes from $\\propto \\omega^{3/4}$ found in iso-osmotic solutions to $\\propto \\omega^{1/2}$ in hypo--osmotic solutions; the first situation is typical of bending modes in isotropic \\textit{in vitro} reconstituted F--actin networks, and the second could indicate that the restructured cytoskeleton behaves as a gel with "\\textit{dangling branches}". The insights gained ...

  19. Toward utilization of MCNP5 particle track output file for simulation problems in photon spectrometry

    Science.gov (United States)

    Stankovic, Jelena; Marinkovic, Predrag; Ciraj-Bjelac, Olivera; Kaljevic, Jelica; Arandjic, Danijela; Lazarevic, Djordje

    2015-10-01

    Pulse height distribution (PHD) registered by a spectrometer is influenced by various physical phenomena such as photon interactions as well as disturbance produced by the electronic circuits inside the spectrometer. Therefore, spectrometry measurements of gamma and X-ray radiation inaccurately represent primary spectra. In order to overcome spectrum disruption, spectrum unfolding has to be applied. One of the common tools used in the unfolding process is Monte Carlo simulation of spectrometer response to monochromatic photons. The purpose of this work is to develop a new method for simulating CdTe semiconductor spectrometer response to monochromatic photons that can be further used for the spectrum unfolding procedure. The method is based upon post-processing of the particle track (PTRAC) output file generated by the MCNP5 program. In addition to the spectrometry output, this method provides information for each specific photon interaction inside the spectrometer active volume, which is required when taking into account spectrometer charge collection. The PTRAC generated detector response and the measured spectrum were in good agreement. The results obtained showed that this method can be used to generate precise response functions of gamma and X-ray spectrometers.

  20. Design and testing of monolithic active pixel sensors for charged particle tracking

    CERN Document Server

    Deptuch, G; Claus, G; Colledani, C; Dulinski, W; Gornushkin, Y; Husson, D; Riester, J L; Winter, M

    2002-01-01

    A monolithic active pixel sensor (MAPS) for charged particle tracking based on a novel detector structure has been proposed, simulated, fabricated and tested. This detector is inseparable from the readout electronics, since both of them are integrated on the same, low- resistivity silicon wafer standard for a CMOS process. The individual pixel is comprised of only three MOS transistors and a photodiode collecting the charge created in the thin undepleted epitaxial layer. This approach provides a low cost, high resolution and thin device with the whole detector area sensitive to radiation (100% fill factor). Detailed device simulations using the ISE-TCAD package have been carried out in order to study the charge. collection mechanism and to validate the proposed idea. In order to demonstrate viability of the technique, two prototype chips were successively fabricated using 0.6 mu m and 0.35 mu m CMOS processes. Both chips have been fully characterized. The pixel conversion gain has been calibrated using a /sup...

  1. Particle tracking carboxyl and transferrin conjugated quantum dots diffusion at living cell surface

    Science.gov (United States)

    Tian, Tian; Zhu, Zhaoqi; Xiao, Zhongdang

    2009-08-01

    Nanotechnologies and nanomaterials have gained much success in the fields of biological applications. In particular, quantum dots (QDs) are emerging as a revolutionary means for imaging and optical detection in opposition to conventional organic dyes. For their robust photostability, large extinction coefficients, and relatively small size, QDs present superior advantages in single molecules monitoring over long time period in living cell. The interaction between functionalized QDs and living cell is the primary problem of the QDs application in living cell. In this work, carboxyl and transferrin conjugated CdS QDs were evaluated using total internal reflect fluorescence (TIRF) microscopy and single particle tracking (SPT) techniques at living cell surface. The diffusion and binding were quantitively measured by mean square displacement (MSD) versus time plotting. To study the influence of different QDs surface on interaction between QDs and cell, dynamic characters of carboxyl and transferrin conjugated QDs were calculated respectively. The photonic characters of QDs were also investigated, considering that functionalized surface can lead to behavior altering of QDs under illuminating. Simultaneous imaging of several QDs with frame rates of up to 30 frames/s and localization accuracy of ~10 nm was present.

  2. Particle tracking velocimetry applied to estimate the pressure field around a Savonius turbine

    Science.gov (United States)

    Murai, Yuichi; Nakada, Taishi; Suzuki, Takao; Yamamoto, Fujio

    2007-08-01

    Particle tracking velocimetry (PTV) is applied to flows around a Savonius turbine. The velocity vector field measured with PTV is utilized to estimate the pressure field around the turbine, as well as to evaluate the torque performance. The main objective of the work is the establishment of the pressure estimation scheme required to discuss the turbine performance. First, the PTV data are interpolated on a regular grid with a fourth-order ellipsoidal differential equation to generate velocity vectors satisfying the third-order spatio-temporal continuity both in time and space. Second, the phase-averaged velocity vector information with respect to the turbine angle is substituted into three different types of pressure-estimating equations, i.e. the Poisson equation, the Navier-Stokes equation and the sub-grid scale model of turbulence. The results obtained based on the Navier-Stokes equation are compared with those based on the Poisson equation, and have shown several merits in employing the Navier-Stokes-based method for the PTV measurement. The method is applied to a rotating turbine with the tip-speed ratio of 0.5 to find the relationship between torque behaviour and flow structure in a phase-averaged sense. We have found that a flow attached to the convex surface of the blades induces low-pressure regions to drive the turbine, namely, the lift force helps the turbine blades to rotate even when the drag force is insufficient. Secondary mechanisms of torque generation are also discussed.

  3. Single-particle tracking of quantum dot-conjugated prion proteins inside yeast cells

    International Nuclear Information System (INIS)

    Research highlights: → We develop a method to track a quantum dot-conjugated protein in yeast cells. → We incorporate the conjugated quantum dot proteins into yeast spheroplasts. → We track the motions by conventional or 3D tracking microscopy. -- Abstract: Yeast is a model eukaryote with a variety of biological resources. Here we developed a method to track a quantum dot (QD)-conjugated protein in the budding yeast Saccharomyces cerevisiae. We chemically conjugated QDs with the yeast prion Sup35, incorporated them into yeast spheroplasts, and tracked the motions by conventional two-dimensional or three-dimensional tracking microscopy. The method paves the way toward the individual tracking of proteins of interest inside living yeast cells.

  4. Single-particle tracking of quantum dot-conjugated prion proteins inside yeast cells

    Energy Technology Data Exchange (ETDEWEB)

    Tsuji, Toshikazu; Kawai-Noma, Shigeko [Department of Biomolecular Engineering, Graduate School of Biosciences and Biotechnology, Tokyo Institute of Technology, B56, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501 (Japan); Pack, Chan-Gi [Cellular Informatics Laboratory, RIKEN Advanced Science Institute, Wako-shi, Saitama 351-0198 (Japan); Terajima, Hideki [Department of Biomolecular Engineering, Graduate School of Biosciences and Biotechnology, Tokyo Institute of Technology, B56, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501 (Japan); Yajima, Junichiro; Nishizaka, Takayuki [Department of Physics, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588 (Japan); Kinjo, Masataka [Laboratory of Molecular Cell Dynamics, Graduate School of Life Sciences, Hokkaido University, Sapporo 001-0021 (Japan); Taguchi, Hideki, E-mail: taguchi@bio.titech.ac.jp [Department of Biomolecular Engineering, Graduate School of Biosciences and Biotechnology, Tokyo Institute of Technology, B56, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501 (Japan)

    2011-02-25

    Research highlights: {yields} We develop a method to track a quantum dot-conjugated protein in yeast cells. {yields} We incorporate the conjugated quantum dot proteins into yeast spheroplasts. {yields} We track the motions by conventional or 3D tracking microscopy. -- Abstract: Yeast is a model eukaryote with a variety of biological resources. Here we developed a method to track a quantum dot (QD)-conjugated protein in the budding yeast Saccharomyces cerevisiae. We chemically conjugated QDs with the yeast prion Sup35, incorporated them into yeast spheroplasts, and tracked the motions by conventional two-dimensional or three-dimensional tracking microscopy. The method paves the way toward the individual tracking of proteins of interest inside living yeast cells.

  5. Belief Consensus Algorithms for Distributed Target Tracking in Wireless Sensor Networks

    CERN Document Server

    Savic, Vladimir; Zazo, Santiago

    2012-01-01

    In distributed target tracking in wireless sensor networks (WSN), agreement on the target state is usually achieved by the construction and maintenance of a communication path. Such an approach lack robustness to failures, and is not applicable to asynchronous networks. Recently, methods have been proposed that can solve these problems using consensus algorithms. However, these methods suffer from at least one of the following problems: i) they do not use fastest consensus methods, and ii) they cannot handle all parametric and nonparametric likelihood functions. In this paper, we propose a general framework for target tracking using distributed particle filtering (DPF) based on three asynchronous belief consensus (BC) algorithms: standard belief consensus (SBC), broadcast gossip (BG), and belief propagation (BP). Since DPF can be also solved (without consensus) by exchanging the observed data, we determine under which conditions BC-based methods are preferred. Finally, we perform extensive simulations to anal...

  6. Robust and highly performant ring detection algorithm for 3d particle tracking using 2d microscope imaging

    CERN Document Server

    Afik, Eldad

    2013-01-01

    Three-dimensional particle tracking is an essential tool in studying dynamics under the microscope, namely, cellular trafficking, bacteria taxis, fluid dynamics in microfluidics devices. The 3d position of a fluorescent particle can be determined using 2d imaging alone, by measuring the diffraction rings generated by an out-of-focus particle, imaged on a single camera. Here I present a ring detection algorithm exhibiting a high detection rate, which is robust to the challenges arising from particles vicinity. It is capable of real time analysis thanks to its high performance and low memory footprint. Many of the algorithmic concepts introduced can be advantageous in other cases, particularly for sparse data. The implementation is based on open-source and cross-platform software packages only, making it easy to distribute and modify. The image analysis algorithm, which is an offspring of the full 3d circle Hough transform, addresses the need to efficiently trace the trajectories of several particles concurrent...

  7. Alpha particle energy response of 1-mm-thick polycarbonate track detectors by 50 Hz-HV electrochemical etching method

    International Nuclear Information System (INIS)

    The electrochemical etching (ECE) method enlarges charged particle tracks to enhance its applications in particular in health physics and radiation dosimetry. The ECE method is usually based on using a high frequency-high voltage (HF-HV) generator with 250-μm-thick polycarbonate track detectors (PCTDs). The authors' recent studies on nitrogen and helium ions and alpha tracks in 1-mm-thick large-size PCTDs under a 50 Hz-HV ECE process provided promising results. In this study, alpha track efficiency and mean track diameter versus energy responses and registration energy range as well as alpha and background track shapes under three sets of 50 Hz-4, 5 and 6 kV applied field conditions have been studied and are reported. The efficiency versus alpha energy has a Bragg-type response from ∼15 keV to ∼4.5 MeV for the field conditions applied with an efficiency value of 40-50 % at the Bragg peak. The results are presented and discussed. (authors)

  8. Effects of nano-SiO{sub 2} particles on surface tracking characteristics of silicone rubber composites

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yong, E-mail: tjuliuyong@tju.edu.cn; Li, Zhonglei; Du, Boxue [Key Laboratory of Smart Grid of Ministry of Education (Tianjin University), School of Electrical Engineering and Automation, Tianjin University, Tianjin 300072 (China)

    2014-09-08

    Compared with neat silicone rubber composites (SiRCs), SiRCs filled with nano-sized SiO{sub 2} particles at weight ratios from 0.1 to 1.0 wt. % exhibit a higher surface flashover voltage and a greater resistance to surface tracking. Scanning electron microscopy images of tracking morphologies indicate that the SiO{sub 2} particles are situated in close proximity to the polymeric chains and act as bridges to stabilize the chains and maintain the structure of the composite. Higher concentrations of nano-sized SiO{sub 2} particles, however, (above 0.3 wt. %) produce defects in the molecular network which lead to reductions in both the surface flashover voltage and the resistance to surface tracking, although these reduced values are still superior to those of neat SiRCs. Therefore, SiRCs filled with nano-sized SiO{sub 2} particles, especially at an optimal weight ratio (0.1 to 0.3 wt. %), may have significant potential applications as outdoor insulators for power systems.

  9. Numerical issues in Lagrangian tracking and topological evolution of fluid particles in wall-bounded turbulent flows

    International Nuclear Information System (INIS)

    The determination of the local Lagrangian evolution of the flow topology in wall-bounded turbulence, and of the Lagrangian evolution associated with entrainment across the turbulent / non-turbulent interface into a turbulent boundary layer, require accurate tracking of a fluid particle and its local velocity gradients. This paper addresses the implementation of fluid-particle tracking in both a turbulent boundary layer direct numerical simulation and in a fully developed channel flow simulation. Determination of the sub-grid particle velocity is performed using both cubic B-spline, four-point Hermite spline and higher-order Hermite spline interpolation. Both wall-bounded flows show similar oscillations in the Lagrangian tracers of both velocity and velocity gradients, corresponding to the movement of particles across the boundaries of computational cells. While these oscillation in the particle velocity are relatively small and have negligible effect on the particle trajectories for time-steps of the order of CFL = 0.1, they appear to be the cause of significant oscillations in the evolution of the invariants of the velocity gradient tensor.

  10. Asynchronous control for networked systems

    CERN Document Server

    Rubio, Francisco; Bencomo, Sebastián

    2015-01-01

    This book sheds light on networked control systems; it describes different techniques for asynchronous control, moving away from the periodic actions of classical control, replacing them with state-based decisions and reducing the frequency with which communication between subsystems is required. The text focuses specially on event-based control. Split into two parts, Asynchronous Control for Networked Systems begins by addressing the problems of single-loop networked control systems, laying out various solutions which include two alternative model-based control schemes (anticipatory and predictive) and the use of H2/H∞ robust control to deal with network delays and packet losses. Results on self-triggering and send-on-delta sampling are presented to reduce the need for feedback in the loop. In Part II, the authors present solutions for distributed estimation and control. They deal first with reliable networks and then extend their results to scenarios in which delays and packet losses may occur. The novel ...

  11. Asynchronous MPI for the Masses

    OpenAIRE

    Wittmann, Markus; Hager, Georg; Zeiser, Thomas; Wellein, Gerhard

    2013-01-01

    We present a simple library which equips MPI implementations with truly asynchronous non-blocking point-to-point operations, and which is independent of the underlying communication infrastructure. It utilizes the MPI profiling interface (PMPI) and the MPI_THREAD_MULTIPLE thread compatibility level, and works with current versions of Intel MPI, Open MPI, MPICH2, MVAPICH2, Cray MPI, and IBM MPI. We show performance comparisons on a commodity InfiniBand cluster and two tier-1 systems in Germany...

  12. A C++ Framework for Conducting High-Speed, Long-Term Particle Tracking Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Kabel, A.C.; /SLAC

    2006-02-06

    For the purpose of conducting parallel, long-term tracking studies of storage rings such as the ones described in [3], [4], maximum execution speed is essential. We describe an approach involving metaprogramming techniques in C++ which results in execution speeds rivaling hand-optimized assembler code for a particular tracking lattice while retaining the generality and flexibility of an all-purpose tracking code.

  13. GAMIFICATION IN ASYNCHRONOUS EDUCATION PROCESS

    Directory of Open Access Journals (Sweden)

    B. P. Dyakonov

    2016-03-01

    Full Text Available The author of the paper discourses on the prospects of education in the context of the global tendency towards informatization and virtualization of the modern world, influence of these processes on personalized senses of education and educational values and related problems of methodological and technological education in relation to the personalized meanings and educational values. Educational individualization is defined by the author as the most expected way of educational evolution. Distance learning is studied as the main example of the modern transformative educational model. Asynchronous education is explored and characterized as one of the distance learning examples. While defining what asynchronous distance learning is, the author explores its role in the specifics of forming a subject to subject educational approach, while forecasting difficulties in creating holistic asynchronous educational environment. Gamification techniques in the educational process are studied with their respective opportunities and threats, examples in grad and post grad professional studies are provided, including but not limited to foreign language studies. Addictiveness as the goal and means of a build in gamification process is explored as the way to bridge the gap between students and the educators. The author studies gamification in the context of minimizing negative connotations from the educational process, while controversies between pain and game approaches of getting knowledge are brought into light.

  14. Developing new optical imaging techniques for single particle and molecule tracking in live cells

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Wei [Iowa State Univ., Ames, IA (United States)

    2010-01-01

    Differential interference contrast (DIC) microscopy is a far-field as well as wide-field optical imaging technique. Since it is non-invasive and requires no sample staining, DIC microscopy is suitable for tracking the motion of target molecules in live cells without interfering their functions. In addition, high numerical aperture objectives and condensers can be used in DIC microscopy. The depth of focus of DIC is shallow, which gives DIC much better optical sectioning ability than those of phase contrast and dark field microscopies. In this work, DIC was utilized to study dynamic biological processes including endocytosis and intracellular transport in live cells. The suitability of DIC microscopy for single particle tracking in live cells was first demonstrated by using DIC to monitor the entire endocytosis process of one mesoporous silica nanoparticle (MSN) into a live mammalian cell. By taking advantage of the optical sectioning ability of DIC, we recorded the depth profile of the MSN during the endocytosis process. The shape change around the nanoparticle due to the formation of a vesicle was also captured. DIC microscopy was further modified that the sample can be illuminated and imaged at two wavelengths simultaneously. By using the new technique, noble metal nanoparticles with different shapes and sizes were selectively imaged. Among all the examined metal nanoparticles, gold nanoparticles in rod shapes were found to be especially useful. Due to their anisotropic optical properties, gold nanorods showed as diffraction-limited spots with disproportionate bright and dark parts that are strongly dependent on their orientation in the 3D space. Gold nanorods were developed as orientation nanoprobes and were successfully used to report the self-rotation of gliding microtubules on kinesin coated substrates. Gold nanorods were further used to study the rotational motions of cargoes during the endocytosis and intracellular transport processes in live mammalian

  15. Use of Image Pro Plus for counting of α particles tracks in CR-39

    International Nuclear Information System (INIS)

    This paper measured the radon radiations present in NORM samples, through the diffusion chambers which contained a nuclear track detector (CR-39). For automatic counting of those tracks the computer program Image Pro plus was used. This paper reports the application of Image Pro plus for counting the nuclear tracks, coming from the radon radiation present in NORM samples. As the radiation rate of 222Rn if proportional to the number of these tracks, the methodology allowed to compare the levels of contamination of the analysed samples. Also, tables and graphics are presented with counting results referring to the stage of validation of Image Pro plus

  16. Some characteristics of the CR-39 solid state nuclear - Track Detector for register of protons and low energy alpha particles

    International Nuclear Information System (INIS)

    Experimental results related to registration properties of the CR-39 Solid State Nuclear Track Detector for charged particles are presented and discussed. The existence of an inverse proportion between the induction time and the temperature as well as normal concentration of solutions, is showed by the study of CR-39 chemical etching characteristics in NaOH and KOH solutions, comprising varied concentration and temperature. The bulk-etch rate and activation energy of the process were obtained. The critical energy and critical energy-loss rate of CR-39 track-detectors for registration of protons were experimentally determined. Samples were exposed to 24 Mev proton beams in the IEN/CNEN Cyclotron (CV-28), using scattering chamber with a tantalum thin target and aluminium absorbers in contact with the samples, in order to provide the required fluctuation in the scattered beam energy. From the mean track-diameter plotted against incident proton energy the critical energy was obtained. From the calculated energy-loss rate vs. energy curve, the critical energy loss rate were evaluated. The CR-39 response for low energy alpha particles (E = 7h) under the conditions of 6.25 N NaOH at 700C. It is shown that successive chemical etchings do not produce the same track geometry as obtained by means of a continous revelation with the same total etching time. (Author)

  17. Single particle tracking with sterol modulation reveals the cholesterol-mediated diffusion properties of integrin receptors

    International Nuclear Information System (INIS)

    A combination of sterol modulation with cyclodextrins plus fluorescence microscopy revealed a biophysical mechanism behind cholesterol’s influence on the diffusion of a ubiquitous class of receptors called integrins. The heterogeneous diffusion of integrins bound to ligand-coated quantum dots was measured using single particle tracking (SPT), and the ensemble changes in integrin diffusion were measured by fluorescence recovery after photobleaching (FRAP). A 25 ± 1% reduction of membrane cholesterol resulted in three significant changes to the diffusion of ligand-bound αPS2CβPS integrins as measured by SPT. There was a 23% increase in ligand-bound mobile integrins; there was a statistically significant increase in the average diffusion coefficient inside zones of confined diffusion, and histograms of confined integrin trajectories showed an increased frequency in the range of 0.1–1 μm2 s−1 and a decreased frequency in the 0.001–0.1 μm2 s−1 range. No statistical change was measured in the duration of confinement nor the size of confined zones. Restoring the cholesterol-depleted cells with exogenous cholesterol or exogenous epicholesterol resulted in similar diffusion properties. Epicholesterol differs from cholesterol in the orientation of a single hydroxyl group. The ability of epicholesterol to substitute for cholesterol suggests a biophysical mechanism for cholesterol’s effect on integrin diffusion. Influences of bilayer thickness, viscosity and organization are discussed as possible explanations for the measured changes in integrin diffusion when the membrane cholesterol concentration is reduced. (paper)

  18. Advanced algorithms for mobile robot motion planning and tracking in structured static environments using particle swarm optimization

    OpenAIRE

    Ćosić Aleksandar; Šušić Marko; Katić Duško

    2012-01-01

    An approach to intelligent robot motion planning and tracking in known and static environments is presented in this paper. This complex problem is divided into several simpler problems. The first is generation of a collision free path from starting to destination point, which is solved using a particle swarm optimization (PSO) algorithm. The second is interpolation of the obtained collision-free path, which is solved using a radial basis function neural network (RBFNN), and trajectory g...

  19. Robust and highly performant ring detection algorithm for 3d particle tracking using 2d microscope imaging

    Science.gov (United States)

    Afik, Eldad

    2015-09-01

    Three-dimensional particle tracking is an essential tool in studying dynamics under the microscope, namely, fluid dynamics in microfluidic devices, bacteria taxis, cellular trafficking. The 3d position can be determined using 2d imaging alone by measuring the diffraction rings generated by an out-of-focus fluorescent particle, imaged on a single camera. Here I present a ring detection algorithm exhibiting a high detection rate, which is robust to the challenges arising from ring occlusion, inclusions and overlaps, and allows resolving particles even when near to each other. It is capable of real time analysis thanks to its high performance and low memory footprint. The proposed algorithm, an offspring of the circle Hough transform, addresses the need to efficiently trace the trajectories of many particles concurrently, when their number in not necessarily fixed, by solving a classification problem, and overcomes the challenges of finding local maxima in the complex parameter space which results from ring clusters and noise. Several algorithmic concepts introduced here can be advantageous in other cases, particularly when dealing with noisy and sparse data. The implementation is based on open-source and cross-platform software packages only, making it easy to distribute and modify. It is implemented in a microfluidic experiment allowing real-time multi-particle tracking at 70 Hz, achieving a detection rate which exceeds 94% and only 1% false-detection.

  20. Modifications of the registration properties of charged particles in a CR-39 polymeric track detector induced by thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Saad, A.F., E-mail: abdallahsaad56@hotmail.com [Physics Department, Faculty of Science, University of Benghazi, Benghazi (Libya); Hamed, N.A.; Abdalla, Y.K.; Tawati, D.M. [Physics Department, Faculty of Science, University of Benghazi, Benghazi (Libya)

    2012-09-15

    The thermal annealing behavior of alpha and fission fragment tracks, following exposure pre- and post-annealing, in a high polymer material of poly allyl diglycol carbonate (PADC), a form of CR-39, has been investigated as a function of temperature and time. Isothermal and isochronal annealing experiments were carried out on CR-39 polymeric detectors exposed to a {sup 252}Cf source. The yields of fission fragment and surviving alpha tracks were measured as a function of annealing time and temperature, as was the variation of fission track diameter with annealing time. The bulk and track etch rates were measured using alpha and fission fragment track diameters and the bulk etch rate was also measured by the weight loss method. The activation energy of annealing was determined using two different models based on the experimental results. This paper presents novel information showing that the annealed CR-39 detectors were demonstrated to be highly sensitive to the fission fragments, but not to alpha particles.

  1. Hitting Families of Schedules for Asynchronous Programs

    OpenAIRE

    Chistikov, Dmitry; Majumdar, Rupak; Niksic, Filip

    2016-01-01

    Asynchronous programming is a ubiquitous idiom for concurrent programming, where sequential units of code, called events, are scheduled and run atomically by a scheduler. While running, an event can post additional events for future execution by the scheduler. Asynchronous programs can have subtle bugs due to the non-deterministic scheduling of events, and a lot of recent research has focused on systematic testing of these programs. Empirically, many bugs in asynchronous programs have small b...

  2. A method for designing asynchronous probabilistic processes

    OpenAIRE

    Abbes, Samy

    2013-01-01

    We present a method for constructing asynchronous probabilistic processes. The asynchronous probabilistic processes thus obtained are called invariant. They generalize the familiar independent and identically distributed sequences of random variables to an asynchronous framework. Invariant processes are shown to be characterised by a finite family of real numbers, their characteristic numbers. Our method provides first a way to obtaining necessary and sufficient normalization conditions for a...

  3. Asynchronous Methods for Deep Reinforcement Learning

    OpenAIRE

    Mnih, Volodymyr; Badia, Adrià Puigdomènech; Mirza, Mehdi; Graves, Alex; Lillicrap, Timothy P.; Harley, Tim; Silver, David; Kavukcuoglu, Koray

    2016-01-01

    We propose a conceptually simple and lightweight framework for deep reinforcement learning that uses asynchronous gradient descent for optimization of deep neural network controllers. We present asynchronous variants of four standard reinforcement learning algorithms and show that parallel actor-learners have a stabilizing effect on training allowing all four methods to successfully train neural network controllers. The best performing method, an asynchronous variant of actor-critic, surpasse...

  4. A novel asynchronous access method with binary interfaces

    Directory of Open Access Journals (Sweden)

    Torres-Solis Jorge

    2008-10-01

    Full Text Available Abstract Background Traditionally synchronous access strategies require users to comply with one or more time constraints in order to communicate intent with a binary human-machine interface (e.g., mechanical, gestural or neural switches. Asynchronous access methods are preferable, but have not been used with binary interfaces in the control of devices that require more than two commands to be successfully operated. Methods We present the mathematical development and evaluation of a novel asynchronous access method that may be used to translate sporadic activations of binary interfaces into distinct outcomes for the control of devices requiring an arbitrary number of commands to be controlled. With this method, users are required to activate their interfaces only when the device under control behaves erroneously. Then, a recursive algorithm, incorporating contextual assumptions relevant to all possible outcomes, is used to obtain an informed estimate of user intention. We evaluate this method by simulating a control task requiring a series of target commands to be tracked by a model user. Results When compared to a random selection, the proposed asynchronous access method offers a significant reduction in the number of interface activations required from the user. Conclusion This novel access method offers a variety of advantages over traditionally synchronous access strategies and may be adapted to a wide variety of contexts, with primary relevance to applications involving direct object manipulation.

  5. Simultaneous Multi-vehicle Detection and Tracking Framework with Pavement Constraints Based on Machine Learning and Particle Filter Algorithm

    Institute of Scientific and Technical Information of China (English)

    WANG Ke; HUANG Zhi; ZHONG Zhihua

    2014-01-01

    Due to the large variations of environment with ever-changing background and vehicles with different shapes, colors and appearances, to implement a real-time on-board vehicle recognition system with high adaptability, efficiency and robustness in complicated environments, remains challenging. This paper introduces a simultaneous detection and tracking framework for robust on-board vehicle recognition based on monocular vision technology. The framework utilizes a novel layered machine learning and particle filter to build a multi-vehicle detection and tracking system. In the vehicle detection stage, a layered machine learning method is presented, which combines coarse-search and fine-search to obtain the target using the AdaBoost-based training algorithm. The pavement segmentation method based on characteristic similarity is proposed to estimate the most likely pavement area. Efficiency and accuracy are enhanced by restricting vehicle detection within the downsized area of pavement. In vehicle tracking stage, a multi-objective tracking algorithm based on target state management and particle filter is proposed. The proposed system is evaluated by roadway video captured in a variety of traffics, illumination, and weather conditions. The evaluating results show that, under conditions of proper illumination and clear vehicle appearance, the proposed system achieves 91.2% detection rate and 2.6% false detection rate. Experiments compared to typical algorithms show that, the presented algorithm reduces the false detection rate nearly by half at the cost of decreasing 2.7%–8.6% detection rate. This paper proposes a multi-vehicle detection and tracking system, which is promising for implementation in an on-board vehicle recognition system with high precision, strong robustness and low computational cost.

  6. Some characteristics of the CR-39 solid state nuclear-track detector for protons and low energy alpha particles

    International Nuclear Information System (INIS)

    Experimental results related to certain registration properties of the CR-39 solid state nuclear-track detector for charged particles are presented and discussed. The determination of the CR-39 chemical etching in NaOH and KOH solutions, comprising concentration (2-10N) and temperature effects (50-900C), showed the existence of an inverse proportion between the induction time and the temperature as well as the normal concentration of the solutions. The critical energy and the critical energy-loss rate of CR-39 track detectors for registration of protons were experimentally determined. A number of samples was exposed to 24MeV proton beams in the IEN-CNEN Cyclotron (CV-28), using a scattering chamber with a tantalum thin target and aluminium absorbers in contact with the samples in order to provide the required fluctuation in the scattered beam energy. From the mean track-diameter plotted against incident proton energy for 16h and 24h chemical etching (6.25 NaOH, 700C), and considering 1.5 μm as the minimum observable track-diameter, the values (21.0 + - 1.5) MeV and (22.5 + - 1.5) MeV were deduced, respectively, for the critical energy. From the calculated energy-loss rate versus energy curve, the critical energy-loss rate was evaluated as 24 + - 2 MeV.cm2/g. Finally, the CR-39 response for low energy alpha particles (E < = 6 MeV) was studied. It was demonstrated also that successive chemical etchings do not produce the same track geometry as obtained by means of a continuous revelation with the same total etching time. (Author)

  7. Recovering the Elemental Composition of Comet Wild 2 Dust in Five Stardust Impact Tracks and Terminal Particles in Aerogel

    International Nuclear Information System (INIS)

    The elemental (non-volatile) composition of five Stardust impact tracks and terminal particles left from capture of Comet 81P/Wild 2 dust were mapped in a synchrotron x-ray scanning microprobe with full fluorescence spectra at each pixel. Because aerogel includes background levels of several elements of interest, we employ a novel 'dual threshold' approach to discriminate against background contaminants: an upper threshold, above which a spectrum contains cometary material plus aerogel and a lower threshold below which it contains only aerogel. The difference between normalized cometary-plus-background and background-only spectra is attributable to cometary material. The few spectra in between are discarded since misallocation is detrimental: cometary material incorrectly placed in the background spectrum is later subtracted from the cometary spectrum, doubling the loss of reportable cometary material. This approach improves precision of composition quantification. We present the refined whole impact track and terminal particle elemental abundances for the five impact tracks. One track shows mass increases in Cr and Mn (1.4x), Cu, As and K (2x), Zn (4x) and total mass (13%) by dual thresholds compared to a single threshold. Major elements Fe and Ni are not significantly affected. The additional Cr arises from cometary material containing little Fe. We exclude Au intermixed with cometary material because it is found to be a localized surface contaminant carried by comet dust into an impact track. The dual threshold technique can be used in other situations where elements of interest in a small sample embedded in a matrix are also present in the matrix itself

  8. Real-time visual sensing system achieving high-speed 3D particle tracking with nanometer resolution.

    Science.gov (United States)

    Cheng, Peng; Jhiang, Sissy M; Menq, Chia-Hsiang

    2013-11-01

    This paper presents a real-time visual sensing system, which is created to achieve high-speed three-dimensional (3D) motion tracking of microscopic spherical particles in aqueous solutions with nanometer resolution. The system comprises a complementary metal-oxide-semiconductor (CMOS) camera, a field programmable gate array (FPGA), and real-time image processing programs. The CMOS camera has high photosensitivity and superior SNR. It acquires images of 128×120 pixels at a frame rate of up to 10,000 frames per second (fps) under the white light illumination from a standard 100 W halogen lamp. The real-time image stream is downloaded from the camera directly to the FPGA, wherein a 3D particle-tracking algorithm is implemented to calculate the 3D positions of the target particle in real time. Two important objectives, i.e., real-time estimation of the 3D position matches the maximum frame rate of the camera and the timing of the output data stream of the system is precisely controlled, are achieved. Two sets of experiments were conducted to demonstrate the performance of the system. First, the visual sensing system was used to track the motion of a 2 μm polystyrene bead, whose motion was controlled by a three-axis piezo motion stage. The ability to track long-range motion with nanometer resolution in all three axes is demonstrated. Second, it was used to measure the Brownian motion of the 2 μm polystyrene bead, which was stabilized in aqueous solution by a laser trapping system. PMID:24216655

  9. Flow Mapping in a Gas-Solid Riser via Computer Automated Radioactive Particle Tracking (CARPT)

    Energy Technology Data Exchange (ETDEWEB)

    Muthanna Al-Dahhan; Milorad P. Dudukovic; Satish Bhusarapu; Timothy J. O' hern; Steven Trujillo; Michael R. Prairie

    2005-06-04

    Statement of the Problem: Developing and disseminating a general and experimentally validated model for turbulent multiphase fluid dynamics suitable for engineering design purposes in industrial scale applications of riser reactors and pneumatic conveying, require collecting reliable data on solids trajectories, velocities ? averaged and instantaneous, solids holdup distribution and solids fluxes in the riser as a function of operating conditions. Such data are currently not available on the same system. Multiphase Fluid Dynamics Research Consortium (MFDRC) was established to address these issues on a chosen example of circulating fluidized bed (CFB) reactor, which is widely used in petroleum and chemical industry including coal combustion. This project addresses the problem of lacking reliable data to advance CFB technology. Project Objectives: The objective of this project is to advance the understanding of the solids flow pattern and mixing in a well-developed flow region of a gas-solid riser, operated at different gas flow rates and solids loading using the state-of-the-art non-intrusive measurements. This work creates an insight and reliable database for local solids fluid-dynamic quantities in a pilot-plant scale CFB, which can then be used to validate/develop phenomenological models for the riser. This study also attempts to provide benchmark data for validation of Computational Fluid Dynamic (CFD) codes and their current closures. Technical Approach: Non-Invasive Computer Automated Radioactive Particle Tracking (CARPT) technique provides complete Eulerian solids flow field (time average velocity map and various turbulence parameters such as the Reynolds stresses, turbulent kinetic energy, and eddy diffusivities). It also gives directly the Lagrangian information of solids flow and yields the true solids residence time distribution (RTD). Another radiation based technique, Computed Tomography (CT) yields detailed time averaged local holdup profiles at

  10. Study of the characteristics of ionizing particles record of CR-39 track detectors

    International Nuclear Information System (INIS)

    The bulk and track etching proprieties of a new Solid State Nuclear Track Detector CR-39 were investigated under different etching conditions. The discussion is based on results obtained using aqueous solutions of KOH with addition of alcoholic solvent to aqueous solutions. It was found that track registration sensitivity can be dramatically changed by using the proper chemical treatment. A method to enlarge and dye etch tracks to be viewed by simple projection on a screen is discussed. The applications of CR-39 in neutron fluence measurements are shown. Graphs are presented of the densities of the registered traces by the detector as a function of etch time both for samples with and without a polycarbonate radiator. (author)

  11. Particle Filtering for Obstacle Tracking in UAS Sense and Avoid Applications

    OpenAIRE

    Anna Elena Tirri; Giancarmine Fasano; Domenico Accardo; Antonio Moccia

    2014-01-01

    Obstacle detection and tracking is a key function for UAS sense and avoid applications. In fact, obstacles in the flight path must be detected and tracked in an accurate and timely manner in order to execute a collision avoidance maneuver in case of collision threat. The most important parameter for the assessment of a collision risk is the Distance at Closest Point of Approach, that is, the predicted minimum distance between own aircraft and intruder for assigned current position and speed. ...

  12. Track structure approach to the calculation of peak 5a to peak 5 (TLD-100) relative intensities following heavy charged particle irradiation

    International Nuclear Information System (INIS)

    A track structure approach to the calculation of the relative strength of localised and de-localised recombination mechanisms leading to composite glow peak 5 in LiF:Mg,Ti following heavy charged particle irradiation is described. (authors)

  13. Confocal fluorescent imaging of tracks from heavy charged particles utilising new Al2O3:C,Mg crystals

    International Nuclear Information System (INIS)

    A completely optical, non-destructive imaging of tracks in a fluorescent crystal provides a new way to detect and to assess doses from heavy charged particles and neutrons. The technique combines confocal fluorescent microscopy with a new radiation-sensitive, luminescent material based on aluminium oxide single crystals doped with carbon, magnesium and having aggregate oxygen vacancy defects (Al2O3:C,Mg). Radiation-induced colour centres in the new material have an absorption band at 620 nm and produce fluorescence at 750 nm with a high quantum yield and a short, 75 ± 5 ns, fluorescence lifetime. Three-dimensional spatial distribution of fluorescent intensity allows one to obtain depth-dose distributions and to discriminate between high- and low-linear energy transfer radiations. Images of single tracks produced by different types of radiation have been obtained. Irradiations with a calibrated 241Am alpha source showed high efficiency for track detection. Thermal neutrons were detected using a nuclear reaction with a 6LiF radiator and production of alpha particles and tritium ions. Fast neutrons were detected using recoil protons produced in a polyethylene radiator installed in front of the crystalline detector. Three-dimensional reconstruction of a recoil proton propagating through the crystal was demonstrated. (authors)

  14. Asynchronous Discussions and Assessment in Online Learning

    Science.gov (United States)

    Vonderwell, Selma; Liang, Xin; Alderman, Kay

    2007-01-01

    This case study explored asynchronous online discussions, assessment processes, and the meaning students derived from their experiences in five online graduate courses at the Colleges of Education of two Midwestern higher education institutions. The findings suggest that asynchronous online discussions facilitate a multidimensional process of…

  15. Kernel density estimation and marginalized-particle based probability hypothesis density filter for multi-target tracking

    Institute of Scientific and Technical Information of China (English)

    张路平; 王鲁平; 李飚; 赵明

    2015-01-01

    In order to improve the performance of the probability hypothesis density (PHD) algorithm based particle filter (PF) in terms of number estimation and states extraction of multiple targets, a new probability hypothesis density filter algorithm based on marginalized particle and kernel density estimation is proposed, which utilizes the idea of marginalized particle filter to enhance the estimating performance of the PHD. The state variables are decomposed into linear and non-linear parts. The particle filter is adopted to predict and estimate the nonlinear states of multi-target after dimensionality reduction, while the Kalman filter is applied to estimate the linear parts under linear Gaussian condition. Embedding the information of the linear states into the estimated nonlinear states helps to reduce the estimating variance and improve the accuracy of target number estimation. The meanshift kernel density estimation, being of the inherent nature of searching peak value via an adaptive gradient ascent iteration, is introduced to cluster particles and extract target states, which is independent of the target number and can converge to the local peak position of the PHD distribution while avoiding the errors due to the inaccuracy in modeling and parameters estimation. Experiments show that the proposed algorithm can obtain higher tracking accuracy when using fewer sampling particles and is of lower computational complexity compared with the PF-PHD.

  16. Asynchronous Parallelization of a CFD Solver

    Directory of Open Access Journals (Sweden)

    Daniel S. Abdi

    2015-01-01

    Full Text Available A Navier-Stokes equations solver is parallelized to run on a cluster of computers using the domain decomposition method. Two approaches of communication and computation are investigated, namely, synchronous and asynchronous methods. Asynchronous communication between subdomains is not commonly used in CFD codes; however, it has a potential to alleviate scaling bottlenecks incurred due to processors having to wait for each other at designated synchronization points. A common way to avoid this idle time is to overlap asynchronous communication with computation. For this to work, however, there must be something useful and independent a processor can do while waiting for messages to arrive. We investigate an alternative approach of computation, namely, conducting asynchronous iterations to improve local subdomain solution while communication is in progress. An in-house CFD code is parallelized using message passing interface (MPI, and scalability tests are conducted that suggest asynchronous iterations are a viable way of parallelizing CFD code.

  17. Neutron response calculation on the basis of variable track etch rates along the secondary particle trajectories in CR-39

    CERN Document Server

    Hermsdorf, D; Dörschel, B; Henniger, J

    1999-01-01

    The calculation of the response of CR-39 detectors exposed to neutrons is of high importance for their dosimetric application. A computer code system has been developed for this purpose. Whereas the generation of secondary charged particles is carried out using non-analogue Monte-Carlo techniques with variance reduction the simulation of the track formation process is treated without any free parameter starting from the etch rate ratio V(REL) only. Results are given for the contribution of recoil protons to the response as a function of the neutron energy and angle of incidence. Furthermore, the influence of an external radiator has been studied. The comparison of the calculated values with experimental data confirm the reliability of the track etch model applied.

  18. A Rao-Blackwellized particle filter for joint parameter estimation and biomass tracking in a stochastic predator-prey system.

    Science.gov (United States)

    Martín-Fernández, Laura; Gilioli, Gianni; Lanzarone, Ettore; Miguez, Joaquin; Pasquali, Sara; Ruggeri, Fabrizio; Ruiz, Diego P

    2014-06-01

    Functional response estimation and population tracking in predator-prey systems are critical problems in ecology. In this paper we consider a stochastic predator-prey system with a Lotka-Volterra functional response and propose a particle filtering method for: (a) estimating the behavioral parameter representing the rate of effective search per predator in the functional response and (b) forecasting the population biomass using field data. In particular, the proposed technique combines a sequential Monte Carlo sampling scheme for tracking the time-varying biomass with the analytical integration of the unknown behavioral parameter. In order to assess the performance of the method, we show results for both synthetic and observed data collected in an acarine predator-prey system, namely the pest mite Tetranychus urticae and the predatory mite Phytoseiulus persimilis. PMID:24506552

  19. Advanced algorithms for mobile robot motion planning and tracking in structured static environments using particle swarm optimization

    Directory of Open Access Journals (Sweden)

    Ćosić Aleksandar

    2012-01-01

    Full Text Available An approach to intelligent robot motion planning and tracking in known and static environments is presented in this paper. This complex problem is divided into several simpler problems. The first is generation of a collision free path from starting to destination point, which is solved using a particle swarm optimization (PSO algorithm. The second is interpolation of the obtained collision-free path, which is solved using a radial basis function neural network (RBFNN, and trajectory generation, based on the interpolated path. The last is a trajectory tracking problem, which is solved using a proportional-integral (PI controller. Due to uncertainties, obstacle avoidance is still not ensured, so an additional fuzzy controller is introduced, which corrects the control action of the PI controller. The proposed solution can be used even in dynamic environments, where obstacles change their position in time. Simulation studies were realized to validate and illustrate this approach.

  20. Articulated Hand Motion Tracking Using ICA-based Motion Analysis and Particle Filtering

    Directory of Open Access Journals (Sweden)

    Makoto Kato

    2006-06-01

    Full Text Available This paper introduces a new representation of hand motions for tracking and recognizing hand-finger gestures in an image sequence. A human hand has many joints, for example our hand model has 15, and its high dimensionality makes it difficult to model hand motions. To make things easier, it is important to represent a hand motion in a low dimensional space. Principle component analysis (PCA has been proposed to reduce the dimensionality. However, the PCA basis vectors only represent global features, which are not optimal for representing intrinsic features. This paper proposes an efficient representation of hand motions by independent component analysis (ICA. The ICA basis vectors represent local features, each of which corresponds to the motion of a particular finger. This representation is more efficient in modeling hand motions for tracking and recognizing handfinger gestures in an image sequence. We will demonstrate the effectiveness of the method by tracking a hand in real image sequences.

  1. Detection of accelerated particles from pulsed plasma discharge using solid state nuclear track detector

    Indian Academy of Sciences (India)

    G M El-Aragi; U Seddik; A Abd El-Haliem

    2007-04-01

    The ion beam of a Mather-type 23.25 J plasma focus device operated with air filling at 10 Torr was registered using CR-39 nuclear track detector. The irradiated samples were etched in NaOH solution at 70°C for 1 h. It is found here that plasma beam contains multi-components of microbeams. The individual track density of microbeams is estimated and the total current density of the plasma stream is measured to be 1.2 mA/cm2. A model for counting the track density of individual microbeams is proposed here. Faraday cup measurements showed the ion pulse with energy ranging from 5.8 keV to 3.3 keV.

  2. Design and simulation of track/hold circuit with CMOS FET for particle detector

    International Nuclear Information System (INIS)

    In this paper, the objective is to realize a Track/Hold Circuit for silicon strip, Si(Li), CdZnTe and CsI detectors etc. By using CMOS transistor to implement various components in electronic circuit, the Track and Hold circuit only made with CMOS FET is succeeded to be designed and simulated. Performance was characterized using PSPICE simulator with BSIMV3.3 parameters of the Proteus. Several measurements of acquisition time can be made from 60 ns to 4.44 μs related to the output resistance, and the integral nonlinearity is good. (authors)

  3. Accurate calculation of Stokes drag for point-particle tracking in two-way coupled flows

    Science.gov (United States)

    Horwitz, J. A. K.; Mani, A.

    2016-08-01

    In this work, we propose and test a method for calculating Stokes drag applicable to particle-laden fluid flows where two-way momentum coupling is important. In the point-particle formulation, particle dynamics are coupled to fluid dynamics via a source term that appears in the respective momentum equations. When the particle Reynolds number is small and the particle diameter is smaller than the fluid scales, it is common to approximate the momentum coupling source term as the Stokes drag. The Stokes drag force depends on the difference between the undisturbed fluid velocity evaluated at the particle location, and the particle velocity. However, owing to two-way coupling, the fluid velocity is modified in the neighborhood of a particle, relative to its undisturbed value. This causes the computed Stokes drag force to be underestimated in two-way coupled point-particle simulations. We develop estimates for the drag force error as function of the particle size relative to the grid size. Because the disturbance field created by the particle contaminates the surrounding fluid, correctly calculating the drag force cannot be done solely by direct interpolation of the fluid velocity. Instead, we develop a correction method that calculates the undisturbed fluid velocity from the computed disturbed velocity field by adding an estimate of the velocity disturbance created by the particle. The correction scheme is tested for a particle settling in an otherwise quiescent fluid and is found to reduce the error in computed settling velocity by an order of magnitude compared with common interpolation schemes.

  4. Particle track membranes and their applications. Proceedings of the 2. Meeting 2-6 December 1991, Szczyrk, Poland

    International Nuclear Information System (INIS)

    The materials (16 papers) of the meeting present the activities of leading European institutions being engaged in the interesting topic. Technologies and methods of PTM (particle track membranes) production by interaction of ion beams with polymeric materials have been broadly discussed. The spectrum of polymeric foils, their applicability as PTM and their properties after irradiation in different conditions have been shown as well. A number of possible applications of PTM and already tested and realized in industry, medicine, biology and physical investigations have also been presented

  5. Dissecting the Cell Entry Pathway of Dengue Virus by Single-Particle Tracking in Living Cells

    NARCIS (Netherlands)

    van der Schaar, Hilde M.; Rust, Michael J.; Chen, Chen; van der Ende-Metselaar, Heidi; Wilschut, Jan; Zhuang, Xiaowei; Smit, Jolanda M.

    2008-01-01

    Dengue virus (DENV) is an enveloped RNA virus that causes the most common arthropod-borne infection worldwide. The mechanism by which DENV infects the host cell remains unclear. In this work, we used live-cell imaging and single-virus tracking to investigate the cell entry, endocytic trafficking, an

  6. Abstracting Asynchronous Multi-Valued Networks

    Directory of Open Access Journals (Sweden)

    J. Steggles

    2011-01-01

    Full Text Available Multi-valued networks (MVNs provide a simple yet expressive qualitative state based modelling approach for biological systems. In this paper we develop an abstraction theory for asynchronous MVNs that allows the state space of a model to be reduced while preserving key properties. The abstraction theory therefore provides a mechanism for coping with the state space explosion problem and supports the analysis and comparison of MVNs. We take as our starting point the abstraction theory for synchronous MVNs which uses the under- approximation approach of trace set inclusion. We show this definition of asynchronous abstraction allows the sound inference of analysis properties and preserves other interesting model properties. One problem that arises in the asynchronous case is that the trace set of an MVN can be infinite making a simple trace set inclusion check infeasible. To address this we develop a decision procedure for checking asynchronous abstractions based on using the finite state graph of an asynchronous MVN to reason about its trace semantics and formally show that this decision procedure is correct. We illustrate the abstraction techniques developed by considering two detailed case studies in which asynchronous abstractions are identified and validated for existing asynchronous MVN models taken from the literature.

  7. A comparison of single particle tracking and temporal image correlation spectroscopy for quantitative analysis of endosome motility

    DEFF Research Database (Denmark)

    Lund, F. W.; Wustner, D.

    2013-01-01

    Single particle tracking (SPT) is becoming a standard method to extract transport parameters from time-lapse image sequences of fluorescent vesicles in living cells. Another method to obtain these data is temporal image correlation spectroscopy (TICS), but this method is less often used for...... measurement of intracellular vesicle transport. Here, we present an extensive comparison of SPT and TICS. First we examine the effect of photobleaching, shading and noise on SPT and TICS analysis using simulated image sequences. To this end, we developed a simple photophysical model, which relates spatially...... varying illumination intensity to the bleaching propensity and fluorescence intensity of the moving particles. We found that neither SPT nor TICS are affected by photobleaching per se, but the transport parameters obtained by both methods are sensitive to the signal-to-noise ratio. In addition, the number...

  8. Particle tracking in E - φ space for synchrotron design and diagnosis

    International Nuclear Information System (INIS)

    The single particle equations for the longitudinal motion in a synchrotron can be faithfully represented as a one-turn mapping of a particle's phase space position relative to the synchronous particle. Applied to a distribution of particles, the mapping can be used to model the evolution of bunches to test beam manipulations or to extract the time dependence of quantities like the bunching factor, momentum spread, etc. which can be difficult to calculate. Such modelling requires rather few representative particles, permitting numerical experimentation and exploratory design trials. By modifying the mapping each turn to introduce the collective effects of the distribution, one can model such processes as phase feedback, space-charge effects, coupled bunch motion, etc. Calculations of this type offer quantitative performance predictions, aid diagnosis of existing accelerators, and contribute to the understanding of the underlying dynamics. This talk introduces the tools and some illustrations

  9. Infrared Spectroscopy of Wild 2 Particle Hypervelocity Tracks in Stardust Aerogel: Evidence for the presence of Volatile Organics in Comet Dust

    Energy Technology Data Exchange (ETDEWEB)

    Bajt, S; Sandford, S A; Flynn, G J; Matrajt, G; Snead, C J; Westphal, A J; Bradley, J P

    2007-08-28

    Infrared spectroscopy maps of some tracks, made by cometary dust from 81P/Wild 2 impacting Stardust aerogel, reveal an interesting distribution of volatile organic material. Out of six examined tracks three show presence of volatile organic components possibly injected into the aerogel during particle impacts. When particle tracks contained excess volatile organic material, they were found to be -CH{sub 2}-rich. Off-normal particle tracks could indicate impacts by lower velocity particles that could have bounced off the Whipple shield, therefore carry off some contamination from it. However, this theory is not supported by data that show excess organic-rich material in normal and off-normal particle tracks. It is clear that the population of cometary particles impacting the Stardust aerogel collectors also include grains that contained little or none of this volatile organic component. This observation is consistent with the highly heterogeneous nature of the collected grains, as seen by a multitude of other analytical techniques. We propose that at least some of the volatile organic material might be of cometary origin based on supporting data shown in this paper. However, we also acknowledge the presence of carbon (primarily as -CH{sub 3}) in the original aerogel, which complicates interpretation of these results.

  10. Burst-Mode Asynchronous Controllers on FPGA

    Directory of Open Access Journals (Sweden)

    Duarte L. Oliveira

    2008-01-01

    Full Text Available FPGAs have been mainly used to design synchronous circuits. Asynchronous design on FPGAs is difficult because the resulting circuit may suffer from hazard problems. We propose a method that implements a popular class of asynchronous circuits, known as burst mode, on FPGAs based on look-up table architectures. We present two conditions that, if satisfied, guarantee essential hazard-free implementation on any LUT-based FPGA. By doing that, besides all the intrinsic advantages of asynchronous over synchronous circuits, they also take advantage of the shorter design time and lower cost associated with FPGA designs.

  11. Carrying Synchronous Voice Data On Asynchronous Networks

    Science.gov (United States)

    Bergman, Larry A.

    1990-01-01

    Buffers restore synchronism for internal use and permit asynchronism in external transmission. Proposed asynchronous local-area digital communication network (LAN) carries synchronous voice, data, or video signals, or non-real-time asynchronous data signals. Network uses double buffering scheme that reestablishes phase and frequency references at each node in network. Concept demonstrated in token-ring network operating at 80 Mb/s, pending development of equipment operating at planned data rate of 200 Mb/s. Technique generic and used with any LAN as long as protocol offers deterministic (or bonded) access delays and sufficient capacity.

  12. Improved Particle Filter for Passive Target Tracking%改进粒子滤波在被动目标跟踪中的应用

    Institute of Scientific and Technical Information of China (English)

    邓小龙; 谢剑英; 杨煜普

    2005-01-01

    As a new method for dealing with any nonlinear or non-Gaussian distributions, based on the Monte Carlo methods and Bayesian filtering, particle filters (PF) are favored by researchers and widely applied in many fields. Based on particle filtering, an improved extended Kalman filter (EKF) proposal distribution is presented. Evaluation of the weights is simplified and other improved techniques including the residual resampling step and Markov Chain Monte Carlo method are introduced for target tracking. Performances of the EKF, basic PF and the improved PF are compared in target tracking examples. The simulation results confirm that the improved particle filter outperforms the others.

  13. Scale-Dependent Fracture-Matrix Interactions and Their Impact on Radionuclide Transport: Development of efficient particle-tracking methods

    Energy Technology Data Exchange (ETDEWEB)

    Rajaram, Harihar [University of Colorado, Boulder; Brutz, Michael [University of Colorado, Boulder; Klein, Dylan R [University of Colorado, Boulder; Mallikamas, Wasin [University of Colorado, Boulder

    2014-09-18

    Matrix Diffusion and Adsorption within a rock matrix are important mechanisms for retarding transport of radionuclides in fractured rock. Due to computational limitations and difficulties in characterizing complex subsurface systems, diffusive exchange between a fracture network and surrounding rock matrix is often modeled using simplified conceptual representations. There is significant uncertainty in “effective” parameters used in these models, such as the “effective matrix diffusivity”. Often, these parameters are estimated by fitting sparse breakthrough data, and estimated values fall outside meaningful ranges, because simplified interpretive models do not consider complex three-dimensional flow. There is limited understanding of the relationship between the effective parameters and rock mass characteristics including network structure and matrix properties. There is also evidence for an apparent scale-dependence in “effective matrix diffusion” coefficients. These observations raise questions on whether fracture-matrix interaction parameters estimated from small-scale tracer tests can be used for predicting radionuclide fate and transport at the scale of DOE field sites. High-resolution three-dimensional Discrete-Fracture-Network-Matrix (DFNM) models based on well-defined local scale transport equations can help to address some of these questions. Due to tremendous advances in computational technology over the last 10 years, DFNM modeling in relatively large domains is now feasible. The overarching objective of our research is to use DFNM modeling to improve fundamental understanding of how effective parameters in conceptual models are related to fracture network structure and matrix properties. An advanced three-dimensional DFNM model is being developed, which combines upscaled particle-tracking algorithms for fracture-matrix interaction and a parallel fracture-network flow simulator. The particle-tracking algorithms allow complexity in flow fields

  14. 3D silicon sensors with variable electrode depth for radiation hard high resolution particle tracking

    International Nuclear Information System (INIS)

    3D sensors, with electrodes micro-processed inside the silicon bulk using Micro-Electro-Mechanical System (MEMS) technology, were industrialized in 2012 and were installed in the first detector upgrade at the LHC, the ATLAS IBL in 2014. They are the radiation hardest sensors ever made. A new idea is now being explored to enhance the three-dimensional nature of 3D sensors by processing collecting electrodes at different depths inside the silicon bulk. This technique uses the electric field strength to suppress the charge collection effectiveness of the regions outside the p-n electrodes' overlap. Evidence of this property is supported by test beam data of irradiated and non-irradiated devices bump-bonded with pixel readout electronics and simulations. Applications include High-Luminosity Tracking in the high multiplicity LHC forward regions. This paper will describe the technical advantages of this idea and the tracking application rationale

  15. Use of plastic optical fibers for charged particle tracking in high energy physics

    International Nuclear Information System (INIS)

    A large tracking detector consisting of scintillating plastic optical fibers has been chosen by the DO collaboration as a part of a planned upgrade at the Fermilab Tevatron. The tracker will utilize a state of the art photodetector known as the Visible Light Photon Counter. The benefits of fiber tracking in high energy physics will be presented along with recent progress in several key areas, including: optimization of scintillating dyes and light yields, fiber construction, fiber ribbon manufacture and placement, optical transmission and photodetection. The current status of the D0 development effort will be outlined, including results from the characterization of 5,000 channels of VLPC. Finally, results from simulations of expected detector performance will be shown and discussed

  16. Initial recombination in the track of heavy charged particles: Numerical solution for air filled ionization chambers

    DEFF Research Database (Denmark)

    Kaiser, Franz-Joachim; Bassler, Niels; Tölli, Heikki;

    2012-01-01

    this study the effect of the underlying dose distribution on columnar recombination, a quantitative model for initial recombination,is investigated. Material and Methods Jaffe’s theory, formulated in 1913 quantifies initial recombination by elemental processes, providing an analytical (closed) solution...... 3D). The investigated charge carrier distributions are based on track structure models, which follow a 1/r2 behavior at larger radii and show a constant value at small radii. The results of the calculations are compared to the initial formulation and to data obtained in experiments using carbon ion....... Here, we investigate the effect of the underlying charged carrier distribution around a carbon ion track. The fundamental partial differential equation, formulated by Jaffe, is solved numerically taking into account more realistic charge carrier distributions by the use of a computer program (Gascoigne...

  17. Applications of particle-tracking techniques to bank infiltration: a case study from El Paso, Texas, USA

    Science.gov (United States)

    Abdel-Fattah, Ahmad; Langford, Richard; Schulze-Makuch, Dirk

    2008-08-01

    This paper presents results of a small scale study that utilized particle-tracking techniques to evaluate transport of river water through an alluvial aquifer in a bank infiltration testing site in El Paso, Texas, USA. The particle-tracking survey was used to better define filtration parameters. Several simulations were generated to allow visualization of the effects of well placement and pumping rate on flow paths, travel time, the size of the pumping influence zone, and proportion of river-derived water and groundwater mixing in the pumping well. Simulations indicate that migration of river water into the aquifer is generally slow. Most water does not arrive at the well by the end of an 18-day pumping period at 0.54 m3/min pumping rate for a well located 18 m from the river. Forty-four percent of the water pumped from the well was river water. The models provided important information needed to design appropriate sampling schedules for bank filtration practices and ensured meeting adequate soil-retention times. The pumping rate has more effect on river water travel time than the location of the pumping well from the river. The examples presented in this paper indicate that operating the pumping well at a doubled distance from the river increased the time required for the water to travel to the well, but did not greatly change the capture zone.

  18. 3D Joint Speaker Position and Orientation Tracking with Particle Filters

    OpenAIRE

    Carlos Segura; Javier Hernando

    2014-01-01

    This paper addresses the problem of three-dimensional speaker orientation estimation in a smart-room environment equipped with microphone arrays. A Bayesian approach is proposed to jointly track the location and orientation of an active speaker. The main motivation is that the knowledge of the speaker orientation may yield an increased localization performance and vice versa. Assuming that the sound produced by the speaker is originated from his mouth, the center of the head is deduced based ...

  19. NIR-emitting molecular-based nanoparticles as new two-photon absorbing nanotools for single particle tracking

    Science.gov (United States)

    Daniel, J.; Godin, A. G.; Clermont, G.; Lounis, B.; Cognet, L.; Blanchard-Desce, M.

    2015-07-01

    In order to provide a green alternative to QDs for bioimaging purposes and aiming at designing bright nanoparticles combining both large one- and two-photon brightness, a bottom-up route based on the molecular engineering of dedicated red to NIR emitting dyes that spontaneously form fluorescent organic nanoparticles (FONs) has been implemented. These fully organic nanoparticles built from original quadrupolar dyes are prepared using a simple, expeditious and green protocol that yield very small molecular-based nanoparticles (radius ~ 7 nm) suspension in water showing a nice NIR emission (λem=710 nm). These FONs typically have absorption coefficient more than two orders larger than popular NIR-emitting dyes (such as Alexa Fluor 700, Cy5.5 ….) and much larger Stokes shift values (i.e. up to over 5500 cm-1). They also show very large two-photon absorption response in the 800-1050 nm region (up to about 106 GM) of major promise for two-photon excited fluorescence microscopy. Thanks to their brightness and enhanced photostability, these FONs could be imaged as isolated nanoparticles and tracked using wide-field imaging. As such, thanks to their size and composition (absence of heavy metals), they represent highly promising alternatives to NIR-emitting QDs for use in bioimaging and single particle tracking applications. Moreover, efficient FONs coating was achieved by using a polymeric additive built from a long hydrophobic (PPO) and a short hydrophilic (PEO) segment and having a cationic head group able to interact with the highly negative surface of FONs. This electrostatically-driven interaction promotes both photoluminescence and two-photon absorption enhancement leading to an increase of two-photon brightness of about one order of magnitude. This opens the way to wide-field single particle tracking under two-photon excitation

  20. Implementing LOTOS as asynchronously Communicating Processes

    OpenAIRE

    Sjödin, Peter

    1990-01-01

    A technique is presented for translating LOTOS specifications into implementations executing as asynchronously communicating processes. This generation of implementations is described as transformations of LOTOS expressions. A protocol for implementing LOTOS synchronisation is described.

  1. Simulated tritium concentrations in river waters of the western Lake Taupo catchment, New Zealand with MODPATH particle tracking

    Directory of Open Access Journals (Sweden)

    M. A. Gusyev

    2014-03-01

    Full Text Available We simulated in a previous study tritium concentrations in the river waters of the western Lake Taupo catchment (WLTC using MODFLOW/MT3DMS model (Gusyev et al., 2013. The model was calibrated to match simulated tritium to measured tritium in river waters at baseflows of the Waihaha, Whanganui, Whareroa, Kuratau and Omori river catchments of the WLTC. Following from this work we now utilized the same MODFLOW model for the WLTC to calculate the pathways of groundwater particles (and their corresponding tritium concentrations using steady-state particle tracking with MODPATH. In order to simulate baseflow tritium concentrations with MODPATH, transit time distributions (TTDs such as cumulative frequency distribution (CFD and probability density function (PDF are generated with particle tracking for the river networks of the five WLTC catchment outflows. Then, PDFs are used in the convolution integral with tritium concentration time series obtained in the precipitation. The resulting MODPATH tritium concentrations yield a very good match to measured tritium concentrations and are similar to the MT3DMS simulated tritium concentrations, with the greatest variation occurring around the bomb peak. MODPATH and MT3DMS also yield similar Mean Transit Times (MTT of groundwater contribution to river baseflows, but the actual shape of the TTDs is strikingly different. While both distributions provide valuable information, the methodologies used to derive the TTDs are fundamentally different and hence must be interpreted differently. With the current models setting, only the methodology used with MODPATH provides the true TTD for use with the convolution integral.

  2. Asynchronous Data Fusion With Parallel Filtering Frame

    OpenAIRE

    Na Li; Junhui Liu

    2011-01-01

    This paper studies the design of data fusion algorithm for asynchronous system with integer times sampling. Firstly, the multisensor asynchronous samplings is mapped to the basic axis, accordingly a sampling sequence of single sensor can be taken. Secondly, aiming at the sensor with the densest sampling points, the modified parallel filtering is given. Afterwards, the sequential filtering fusion method is introduced to deal with the case that there are multiple mapped measurements at some sam...

  3. REACTIVE POWER COMPENSATION IN ASYNCHRONOUS ELECTRIC DRIVES

    Directory of Open Access Journals (Sweden)

    V.S. Malyar

    2013-10-01

    Full Text Available A problem of calculating capacity of cosine capacitors for individual compensation of reactive power in asynchronous electric drives in stationary and transient operation modes is considered. The algorithm introduced employs a high-adequacy mathematical model of asynchronous motor developed on the theory of representing vectors which takes into account both the magnetic core saturation and the current displacement in the rotor bars.

  4. Asynchronous communication in real space process algebra

    OpenAIRE

    Baeten, JCM Jos; Bergstra, JA Jan

    1992-01-01

    A version of classical real space process algebra is given in which messages travel with constant speed through a three-dimensional medium. It follows that communication is asynchronous and has a broadcasting character. A state operator is used to describe asynchronous message transfer and a priority mechanism allows to express the broadcasting mechanism. As an application, a protocol is specified in which the receiver moves with respect to the sender.

  5. Performance Analysis of Asynchronous Multicarrier Wireless Networks

    OpenAIRE

    Lin, Xingqin; Jiang, Libin; Andrews, Jeffrey G.

    2014-01-01

    This paper develops a novel analytical framework for asynchronous wireless networks deploying multicarrier transmission. Nodes in the network have different notions of timing, so from the viewpoint of a typical receiver, the received signals from different transmitters are asynchronous, leading to a loss of orthogonality between subcarriers. We first develop a detailed link-level analysis based on OFDM, based on which we propose a tractable system-level signal-to-interference-plus-noise ratio...

  6. Fragmentation studies in heavy charged particle beams by means of track etch detectors

    Czech Academy of Sciences Publication Activity Database

    Jadrníčková, Iva; Spurný, František

    Praha : ČVUT v Praze, 2006 - (Losinská, J.), s. 114-117 ISBN 80-01-03575-1. [Dny radiační ochrany /28./. Luhačovice (CZ), 20.11.2006-24.11.2006] R&D Projects: GA ČR GA202/04/0795; GA ČR(CZ) GD202/05/H031 Institutional research plan: CEZ:AV0Z10480505 Keywords : linear energy transfer * track detectors * fragmentation Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

  7. A novel approach to particle track etching: surfactant enhanced control of pore morphology

    International Nuclear Information System (INIS)

    Based on the understanding of the mechanism behind a long observed but thus far unexplained effect, a new method to control the geometry of nano- and micropores is described. Surfactant molecules added to an etching solution used for etching out ion tracks, create a steric-hindrance effect which is responsible for the formation of 'bottleneck' or 'cigar-like' pores. Filtration membranes thus obtained exhibit significantly improved flow rates without deterioration in the retention properties. New applications are made possible with these new pore geometries

  8. Track etch and thermo luminescent detectors response to high energy charged particles

    Czech Academy of Sciences Publication Activity Database

    Spurný, František; Jadrníčková, Iva

    2008-01-01

    Roč. 43, Supp. 1 (2008), S169-S173. ISSN 1350-4487. [International Conference on Solids /23./. Beijing, 11.09.2006-15.09.2006] R&D Projects: GA ČR GA202/04/0795 Grant ostatní: Evropské společenství(XE) ILSRA - 2004 - 248 Institutional research plan: CEZ:AV0Z10480505 Keywords : track etch detector * thermoluminescent detectors * LET spectrometry Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.267, year: 2008

  9. Dynamic melting and impurity particle tracking in continuously adjustable AC magnetic field

    Science.gov (United States)

    Bojarevics, V.; Pericleous, K.

    2016-07-01

    The analysis of semi-levitation melting is extended to account for the presence of particles (impurities, broken metal dendrite agglomerates, bubbles) during the full melting cycle simulated numerically using the pseudo-spectral schemes. The AC coil is dynamically moving with the melt front progress, while the generated Joule heat serves to enhance the melting rate. The electromagnetic force is decomposed into the time average and the oscillating parts. The time average effects on the particle transport are investigated previously using approximations derived for a locally uniform magnetic field. This paper presents expressions for the skin-layer type of the AC force containing also the pulsating part which contributes to the particle drag by the ‘history’ and ‘added mass’ contributions. The intense turbulence in the bulk of molten metal additionally contributes to the particle dispersion. The paper attempts to demonstrate the importance of each of the mentioned effects onto the particle transport during the melting until the final pouring stage. The method could be extended to similar AC field controlled melting/solidification processes.

  10. Direct multi-scale reconstruction of velocity fields from measurements of particle tracks

    CERN Document Server

    Kelley, Douglas H

    2010-01-01

    We present a method for reconstructing two-dimensional velocity fields at specified length scales using observational data from tracer particles in a flow, without the need for interpolation or smoothing. The algorithm, adapted from techniques proposed for oceanography, involves a least-squares projection of the measurements onto a set of two-dimensional, incompressible basis modes with known length scales. Those modes are constructed from components of the velocity potential function, which accounts for inflow and outflow at the open boundaries of the measurement region; and components of the streamfunction, which accounts for the remainder of the flow. All calculations are evaluated at particle locations, without interpolation onto an arbitrary grid. Since the modes have a well-defined length scales, scale-local flow properties are available directly. The technique eliminates outlier particles automatically and reduces the apparent compressibility of the data. Moreover the technique can be used to produce s...

  11. Simulating biodegradation under mixing-limited conditions using Michaelis-Menten (Monod) kinetic expressions in a particle tracking model

    Science.gov (United States)

    Ding, Dong; Benson, David A.

    2015-02-01

    Recent studies have demonstrated that effective field-scale bioremediation reactions rates are significantly lower than batch- or lab-scale rates, when the same law of mass action is used to represent the reaction at both scales. The mismatch is usually attributed to poor mixing of reactants brought about by heterogeneity. A recent method, based on a purely Lagrangian particle tracking (PT) theoretical development, successfully reproduces the effects of mixing-limited bimolecular reaction (A + B → C) from two benchmark experiments. In this numerical method, the reactants are represented by particles, and the small-scale physics are directly translated into a combination of two probabilities that govern whether: (1) reactant particles are collocated during a short time interval, and (2) two collocated particles favorably transform into a reaction. The latter is due to thermodynamics and is independent of scale of mixing. The former directly accounts for the degree of mixing in any system. We extend the application of the PT method to biodegradation, which is commonly characterized by more complex Michaelis-Menten (Monod) chemical kinetics. The advantage of the PT method is that it explains the variation of reaction rate based on mixing-controlled particle collisions instead of using empirical parameters. The PT method not only matches the Michaelis-Menten (Monod) equation under ideal conditions, but also captures the characteristics of non-ideal conditions such as imperfect mixing, disequilibrium, and limited availability of the active sites. We show these using hypothetical systems and also successfully apply the method to a column study of carbon tetrachloride biodegradation.

  12. Simulations of DSB Yields and Radiation-induced Chromosomal Aberrations in Human Cells Based on the Stochastic Track Structure iIduced by HZE Particles

    Science.gov (United States)

    Ponomarev, Artem; Plante, Ianik; George, Kerry; Wu, Honglu

    2014-01-01

    The formation of double-strand breaks (DSBs) and chromosomal aberrations (CAs) is of great importance in radiation research and, specifically, in space applications. We are presenting a new particle track and DNA damage model, in which the particle stochastic track structure is combined with the random walk (RW) structure of chromosomes in a cell nucleus. The motivation for this effort stems from the fact that the model with the RW chromosomes, NASARTI (NASA radiation track image) previously relied on amorphous track structure, while the stochastic track structure model RITRACKS (Relativistic Ion Tracks) was focused on more microscopic targets than the entire genome. We have combined chromosomes simulated by RWs with stochastic track structure, which uses nanoscopic dose calculations performed with the Monte-Carlo simulation by RITRACKS in a voxelized space. The new simulations produce the number of DSBs as function of dose and particle fluence for high-energy particles, including iron, carbon and protons, using voxels of 20 nm dimension. The combined model also calculates yields of radiation-induced CAs and unrejoined chromosome breaks in normal and repair deficient cells. The joined computational model is calibrated using the relative frequencies and distributions of chromosomal aberrations reported in the literature. The model considers fractionated deposition of energy to approximate dose rates of the space flight environment. The joined model also predicts of the yields and sizes of translocations, dicentrics, rings, and more complex-type aberrations formed in the G0/G1 cell cycle phase during the first cell division after irradiation. We found that the main advantage of the joined model is our ability to simulate small doses: 0.05-0.5 Gy. At such low doses, the stochastic track structure proved to be indispensable, as the action of individual delta-rays becomes more important.

  13. A cascade particle fractionator using mica track microfilters for the filtration of hot and radioactive waste gases

    International Nuclear Information System (INIS)

    A new type of filter was developed: We produced nuclear track microfilters made of mica. We tested this new product under field conditions at an industrial plant. These new microfilters are heat-resistant at temperatures up to 5000C. Additionally, mica microfilters are resistant against practically all chemicals, with the exception of hydrofluoric acid or hot concentrated alcali hydroxyd solutions. Mica microfilters are used in aerosol research and in pollution control investigations. The first application of mica microfilters was in the form of a filtration cascade used in the gas exit channel of a sinteroven. Here we purified hot (0C) waste gases containing radioactive aerosols. A continued application of this new filtration cascade shall be an alternative to the known cascade impactors or optical methods, used in environmental aerosol research. Our cascade particle fractionator allows also the investigation of the aerosol-size distribution, the form of the individual aerosol-particles and the chemical composition of individual aerosol-particles (microprobe chemical analysis). (orig./PW)

  14. A cellular-automata and particle-tracking simulation of abrasive jet micromachining of polymethyl-methacrylate

    International Nuclear Information System (INIS)

    A cellular automaton simulation which is able to predict the geometry of micro-features etched into ductile erosive targets, as a result of abrasive jet micromachining (AJM), is presented. Similar to a previous simulation for the AJM of brittle erosive targets, the movement of individual erodent particles is tracked in a simulated environment, including their collisions with, and ricochet from, the mask and target substrate modeled as cellular-automatons. A new cell erosion algorithm is presented in order to allow the previous simulation to be applied to the AJM of ductile materials. A previously published empirical erosion rule, which related the erosion rate of ductile substrates caused by a jet, was also proven to be applicable, to a good approximation, to single particle impacts. With this new cell erosion algorithm, the predictions of the model compared well with measurements of the surface evolution of unmasked channels, masked micro-holes and micro-channels machined in polymethyl-methacrylate. The results also highlight the importance of modeling the effect of particle size on the prediction of the size and shape of features fabricated in ductile erosive materials using AJM

  15. A Three-Dimensional Particle Tracking Velocimetry System for the Evaluation of Large Eddy Simulation Turbulence Models

    Science.gov (United States)

    Hunt, Joshua M.

    The necessity for evaluating the accuracy and characteristics of new Large-Eddy Simulation (LES) turbulence models in modern fluid mechanics research has inspired the development of a Three-Dimensional Particle Tracking Velocimetry (3DPTV) system capable of producing 3-Dimension 3-Component (3D3C) velocity vector fields. The system is based on the triangulation method of particle location and utilizes an optical system comprised of three 4008 x 2672 charge-coupled devices (CCDs), three 120mm lenses, and a water-filled prism. The tracer particles used in the system were Dynamic, Coherent Structures, and Stretched Vortex Models. The system is preferable to Direct Numerical Simulation (DNS) for such testing in that it is capable of acquiring data at a resolution adequate for a priori testing without the computational restrictions for high Reynolds numbers. In the present configuration, the system is capable of achieving a Taylor-microscale Reynolds number of 214, but with an increase to the CCD resolution of the system, a Taylor-microscale Reynolds number of nearly 400 would be attainable.

  16. Fluorescence labelling as tool for zeolite particle tracking in nanoremediation approaches.

    Science.gov (United States)

    Gillies, Glenn; Mackenzie, Katrin; Kopinke, Frank-Dieter; Georgi, Anett

    2016-04-15

    Colloidal Fe-zeolites such as Fe-BEA-35 are currently under study as new adsorbent and catalyst materials for in-situ chemical oxidation with H2O2. As for nanoremediation in general, the availability of suitable particle detection methods is a requirement for successful process development and particle tracing. Detection and distinguishing between natural colloids and introduced particles with a similar composition are a challenge. By means of fluorescence labelling, a highly specific detection option for Fe-BEA-35 was developed. 'Ship-in-a-bottle' synthesis of fluorescein within the zeolite pores, which was applied for the first time for a BEA type zeolite, provides a product with stable and non-extractable fluorescence. When the fluorescent labelled zeolite is added at a concentration of 1wt.% referring to the total zeolite mass, a very low detection limit of 1mg/L of total zeolite is obtained. Compared to commonly applied turbidity measurements, detection via fluorescence labelling is much more specific and sensitive. Fluorescence is only marginally affected by carboxymethyl cellulose, which is frequently applied as stabilizer in application suspensions but will be depleted upon contact with H2O2. Transport properties of fluorescent labelled and non-labelled Fe-zeolite particles are in agreement as determined in a column study with quartz sand and synthetic groundwater (classified as very hard). PMID:26849345

  17. Development of radiation hard semiconductor sensors for charged particle tracking at very high luminosities

    Science.gov (United States)

    Betancourt, Christopher; Fadeyev, Vitaliy; Sadrozinski, Hartmut F.; Wright, John

    2010-09-01

    The RD50 collaboration (sponsored by the European Organization for Nuclear Research CERN) has been exploring the development of radiation hard semiconductor devices for very high-luminosity colliders since 2002. The target fluence to qualify detectors set by the anticipated dose for the innermost tracking layers of the future upgrade of the CERN large hadron collider (LHC) is 1016 1 MeV neutron equivalent (neq) cm-2. This is much larger than typical fluences in space, but is mainly limited to displacement and total dose damage, without the single-event effects typical for the space environment. RD50 investigates radiation hardening from many angles, including: Search for alternative semiconductor to replace silicon, improvement of the intrinsic tolerance of the substrate material (p- vs. n-type, initial doping concentration, oxygen concentration), optimization of the readout geometry (collection of holes or electrons, surface treatment), novel detector designs (3D, edge-less, interconnects).

  18. Detection threshold control of CR-39 plastic nuclear track detectors for the selective measurement of high LET secondary charged particles

    International Nuclear Information System (INIS)

    The two-step etching method using PEW (Potassium hydroxide + Ethanol + Water) and NaOH solutions was applied to the control of the response of CR-39 plastic nuclear track detectors for the measurement of high LET (linear energy transfer) particles. CR-39 detectors were exposed to several heavy ion beams covering the LET∞H2O range of 30–750 keV/μm from HIMAC (Heavy Ion Medical Accelerator in Chiba) at NIRS (National Institute of Radiological Sciences), Japan. The detectors were pre-etched in PEW solutions with 3 different ethanol concentrations at the temperature of 70 °C for 30–60 min. Then, the detectors were post-etched in 7N NaOH solution at the same temperature for 4–28 h. We found that the response curves and the detection thresholds of the detectors smoothly shifted to higher LET regions as the ethanol concentration increases in PEW solution.

  19. Fluidity evaluation of cell membrane model formed on graphene oxide with single particle tracking using quantum dot

    Science.gov (United States)

    Okamoto, Yoshiaki; Motegi, Toshinori; Iwasa, Seiji; Sandhu, Adarsh; Tero, Ryugo

    2015-04-01

    The lipid bilayer is the fundamental structure of plasma membranes, and artificial lipid bilayer membranes are used as model systems of cell membranes. Recently we reported the formation of a supported lipid bilayer (SLB) on graphene oxide (GO) by the vesicle fusion method. In this study, we conjugated a quantum dot (Qdot) on the SLB surface as a fluorescence probe brighter than dye-labeled lipid molecules, to qualitatively evaluate the fluidity of the SLB on GO by the single particle tracking method. We obtained the diffusion coefficient of the Qdot-conjugated lipids in the SLB on GO. We also performed the Qdot conjugation on the SLB containing a lipid conjugated with polyethylene glycol, to prevent the nonspecific adsorption of Qdots. The difference in the diffusion coefficients between the SLBs on the GO and the bare SiO2 regions was evaluated from the trajectory of single Qdot-conjugated lipid diffusing between the two regions.

  20. Ionization Cluster Size Distributions Created by Low Energy Electrons and Alpha Particles in Nanometric Track Segment in Gases

    CERN Document Server

    Bantsar, Aliaksandr

    2012-01-01

    The interaction of ionizing radiation with nanometric targets is a field of interest for many branches of science such as: radiology, oncology, radiation protection and nanoelectronics. A new experimental technique known as nanodosimetry has been developed for the qualitative as well as quantitative description of these types of interactions. The work presented here is a contribution to this development, namely by further improvement of the new experimental technique called the Jet Counter, originally developed at the Andrzej So{\\l}tan Institute for Nuclear Studies. The Jet Counter is a unique device in the world for studying the interaction of low energy electrons with nanometer targets in the range 2-10 nm (in unit density). The basic experimental result is the frequency distribution of ionization cluster size produced by ionizing particles in a gaseous (nitrogen or propane) nanometric track segment. The first experimental data on the frequency distribution of ionization cluster size produced by low energy ...

  1. Energy deposition by a 106Ru/106Rh eye applicator simulated using LEPTS, a low-energy particle track simulation

    International Nuclear Information System (INIS)

    The present study introduces LEPTS, an event-by-event Monte Carlo programme, for simulating an ophthalmic 106Ru/106Rh applicator relevant in brachytherapy of ocular tumours. The distinctive characteristics of this code are the underlying radiation-matter interaction models that distinguish elastic and several kinds of inelastic collisions, as well as the use of mostly experimental input data. Special emphasis is placed on the treatment of low-energy electrons for generally being responsible for the deposition of a large portion of the total energy imparted to matter. - Highlights: → We present the Monte Carlo code LEPTS, a low-energy particle track simulation. → Carefully selected input data from 10 keV to 1 eV. → Application to an electron emitting Ru-106/Rh-106 plaque used in brachytherapy.

  2. ATLAS Transition Radiation Tracker (TRT): Straw Tubes for Tracking and Particle Identification at the Large Hadron Collider

    CERN Document Server

    Mindur, Bartosz; The ATLAS collaboration

    2016-01-01

    The ATLAS Transition Radiation Tracker (TRT) is the outermost of the three inner detector tracking subsystems and consists of 300000 thin-walled drift tubes (“straw tubes”) that are 4 mm in diameter. The TRT system provides 30 space points with 130 micron resolution for charged tracks with |η| 0.5 GeV/c. The TRT also provides electron identification capability by detecting transition radiation (TR) X-ray photons in a Xe-based working gas mixture. Compared to Run 1, the LHC beams now provide a higher center of mass energy (13 TeV), more bunches with a reduced spacing (25 ns), and more particles in each bunch leading to very challenging, higher occupancies in the TRT. We will present TRT modifications made for Run 2 for in areas: to improve response to the expected much higher rate of hits and to mitigate leaks of the Xe-based active gas mixture. The higher rates required changes to the data acquisition system and introduction of validity gate to reject out-of-time hits. Radiation-induced gain changes in ...

  3. Paramagnetic particles carried by cell-penetrating peptide tracking of bone marrow mesenchymal stem cells, a research in vitro

    International Nuclear Information System (INIS)

    The ability to track the distribution and differentiation of stem cells by high-resolution imaging techniques would have significant clinical and research implications. In this study, a model cell-penetrating peptide was used to carry gadolinium particles for magnetic resonance imaging of the mesenchymal stem cells. The mesenchymal stem cells were isolated from rat bone marrow by Percoll and identified by osteogenic differentiation in vitro. The cell-penetrating peptides labeled with fluorescein-5-isothiocyanate and gadolinium were synthesized by a solid-phase peptide synthesis method and the relaxivity of cell-penetrating peptide-gadolinium paramagnetic conjugate on 400 MHz nuclear magnetic resonance was 5.7311 ± 0.0122 mmol-1 s-1, higher than that of diethylenetriamine pentaacetic acid gadolinium (p < 0.05). Fluorescein imaging confirmed that this new peptide could internalize into the cytoplasm and nucleus. Gadolinium was efficiently internalized into mesenchymal stem cells by the peptide in a time- or concentration-dependent fashion, resulting in intercellular T1 relaxation enhancement, which was obviously detected by 1.5 T magnetic resonance imaging. Cytotoxicity assay and flow cytometric analysis showed the intercellular contrast medium incorporation did not affect cell viability and membrane potential gradient. The research in vitro suggests that the newly constructed peptides could be a vector for tracking mesenchymal stem cells

  4. ATLAS Transition Radiation Tracker (TRT): Straw Tubes for Tracking and Particle Identification at the Large Hadron Collider

    CERN Document Server

    Mindur, Bartosz; The ATLAS collaboration

    2016-01-01

    The ATLAS Transition Radiation Tracker (TRT) is the outermost of the three inner detector tracking subsystems and consists of $\\sim$300000 thin-walled drift tubes (``straw tubes'') that are 4~mm in diameter. The TRT system provides $\\sim$30 space points with $\\sim$130 micron resolution for charged tracks with $|\\eta| $ 0.5 GeV/c. The TRT also provides electron identification capability by detecting transition radiation (TR) X-ray photons in an Xe-based working gas mixture. Compared to Run 1, the LHC beams now provide a higher centre of mass energy (13 TeV), more bunches with a reduced spacing (25 ns), and more particles in each bunch leading to very challenging, higher occupancies in the TRT. Significant modifications of the TRT detector have been made for LHC Run 2 mainly to improve response to the expected much higher rate of hits and to mitigate leaks of the Xe-based active gas mixture. The higher rates required changes to the data acquisition system and introduction of validity gate to reject out-of-time ...

  5. The Physics Performance Of And Level 2 Trigger For The Inner Detector Of Atlas (particle Detector, Muon Tracking, Cern)

    CERN Document Server

    Dankers, R J

    1998-01-01

    In this thesis I describe a study on the physics performance of the ATLAS inner detector and a study on aspects of the second level trigger for the ATLAS inner detector. I present a short discussion of the standard model of particle physics, the Large Hadron Collider (LHC) at CERN and the physics potential of LHC. I introduce the ATLAS experiment, which is one of the four future LHC experiments. The ATLAS detector consists of an inner tracker (inner detector), calorimeters and a muon spectrometer. I present a parameterisation of the reconstruction accuracy of the ATLAS inner tracker for muon tracks. A method is described for calculating from a given set of parameters, representing a muon track in the inner tracker, a smeared set of parameters, as would be obtained from real measurements. Results are presented. I shortly describe supersymmetry and discuss the possibility to find evidence for the existence of super-symmetry with ATLAS. I describe the ATLAS trigger and data acquisition system. The task of the AT...

  6. A new laser test stand for simulating charged-particle tracks

    International Nuclear Information System (INIS)

    We report on the construction of a new laser test stand equipped with a 1064 nm pulsed infrared YAG laser for simulating the passage of a charged particle in a silicon detector. The standard semiconductor repairing tool, the so-called laser-cutter, has been modified to have a newly developed optics which has the ability to reduce the light by the order of 106-108 and to adjust the spot size to several microns. As an application we measured the position dependence of the induced signals in a silicon-strip detector when the laser light hits in the region between the strips. The measurement has shown that this device is very effective in evaluating the detailed response of a silicon detector without using charged particles generated by accelerators. (orig.)

  7. Advances in silicon detectors for particle tracking in extreme radiation environments

    CERN Document Server

    Parker, Sherwood; Da Vià, C; Hasi, J; Jarron, Pierre; Kenney, C; Kok, A; Perozziello, E; Watts, S J

    2003-01-01

    The LHC (Large Hadron Collider) is currently under construction at CERN, the European Laboratory for Particle Physics based in Geneva. The experiments at this accelerator will use substantial numbers of silicon detectors. These are close to the interaction point and will be exposed to very high fluences ( up to 10**1**5 particles cm**-**2) during their operating life. Such detectors are crucial to the disentanglement of important decay events and it is vital to guarantee a homogeneous reliable performance during their operation. Parameters like the charge collection efficiency (CCE) and response time will be discussed. Limitations of present technologies will be analysed and future strategies explored. Results obtained using alternative detector designs, such as 3D geometry, material engineering by oxygen diffusion and unconventional operational conditions are surveyed.

  8. New Software Techniques in Particle Physics and Improved Track Reconstruction for the CMS Experiment

    CERN Document Server

    Hauth, Thomas; Pfeiffer, Andreas

    This thesis presents improvements of the processing speed of HEP applications by making better use of the vector units in modern CPUs. To cope with the increased amount of LHC data, the parallel computing power of GPUs are one option. GPU-optimized reconstruction algorithms which provide a high level of parallelism are presented. Furthermore, the decay of neutral kaons was used to show the benefits of the Geant4-based fitting method when applied to the mass reconstruction of particles.

  9. The Use of Positron Emission Particle Tracking (PEPT) to Study the Movement of Inclusions in Low-Melting-Point Alloy Castings

    Science.gov (United States)

    Griffiths, W. D.; Beshay, Y.; Caden, A. J.; Fan, X.; Gargiuli, J.; Leadbeater, T. W.; Parker, D. J.

    2012-04-01

    Positron emission particle tracking (PEPT) employs a radioactive particle that decays by emission of positrons. These positrons collide with local electrons to produce γ-rays emitted at 180 deg to each other; detection of these γ-ray pairs allows the location of the radioactive particle to be identified within a few millimeters. This technique has been tested to determine its applicability to the study of inclusions in cast metals. To use particles representative of inclusion sizes in castings, both alumina particles and particles of an ion exchange resin were employed. These were within a size range of approximately 60 to 100 μm, made radioactive by adsorption and ion exchange techniques, respectively. The radioactive particles, of activity 100 to 1000 μCi, were introduced into tube-shaped castings made from the low-melting-point alloys Field's metal and Lensalloy-136, cast into an acrylic mold. The technique allowed the particle track to be determined from the point of initial introduction to the final resting place of the particle, with increasing reproducibility being obtained as the reproducibility as the casting technique was improved. Experiments in which filters were placed in to the running system showed that the removal of the particles by the filters varied according to the filter pore size.

  10. Asynchronous Complex Pipeline Design Based on ARM Instruction Set

    Institute of Scientific and Technical Information of China (English)

    WANG Bing; WANG Qin; PENG Rui-hua; FU Yu-zhuo

    2008-01-01

    This paper proposes an asynchronous complex pipeline based on ARM-V3 instruction set. Muller pipeline structure is used as prototype, and the factors which may affect pipeline performance are analyzed. To balance the difficulty of asynchronous design and performance analysis, both complete asynchronous and partial asynchronous structures aere designed and compared. Results of comparison with the well-Rnown industrial product ARM922T verify that about 30% and 40% performance improvement of the partial and complete asynchronous complex pipelines can be obtained respectively. The design methodologies can also be used in the design of other asynchronous pipelines.

  11. 3D Joint Speaker Position and Orientation Tracking with Particle Filters

    Directory of Open Access Journals (Sweden)

    Carlos Segura

    2014-01-01

    Full Text Available This paper addresses the problem of three-dimensional speaker orientation estimation in a smart-room environment equipped with microphone arrays. A Bayesian approach is proposed to jointly track the location and orientation of an active speaker. The main motivation is that the knowledge of the speaker orientation may yield an increased localization performance and vice versa. Assuming that the sound produced by the speaker is originated from his mouth, the center of the head is deduced based on the estimated head orientation. Moreover, the elevation angle of the head of the speaker can be partly inferred from the fast vertical movements of the computed mouth location. In order to test the performance of the proposed algorithm, a new multimodal dataset has been recorded for this purpose, where the corresponding 3D orientation angles are acquired by an inertial measurement unit (IMU provided by accelerometers, magnetometers and gyroscopes in the three-axes. The proposed joint algorithm outperforms a two-step approach in terms of localization and orientation angle precision assessing the superiority of the joint approach.

  12. 3D joint speaker position and orientation tracking with particle filters.

    Science.gov (United States)

    Segura, Carlos; Hernando, Javier

    2014-01-01

    This paper addresses the problem of three-dimensional speaker orientation estimation in a smart-room environment equipped with microphone arrays. A Bayesian approach is proposed to jointly track the location and orientation of an active speaker. The main motivation is that the knowledge of the speaker orientation may yield an increased localization performance and vice versa. Assuming that the sound produced by the speaker is originated from his mouth, the center of the head is deduced based on the estimated head orientation. Moreover, the elevation angle of the head of the speaker can be partly inferred from the fast vertical movements of the computed mouth location. In order to test the performance of the proposed algorithm, a new multimodal dataset has been recorded for this purpose, where the corresponding 3D orientation angles are acquired by an inertial measurement unit (IMU) provided by accelerometers, magnetometers and gyroscopes in the three-axes. The proposed joint algorithm outperforms a two-step approach in terms of localization and orientation angle precision assessing the superiority of the joint approach. PMID:24481230

  13. Two particle tracking and detection in a single Gaussian beam optical trap.

    Science.gov (United States)

    Praveen, P; Yogesha; Iyengar, Shruthi S; Bhattacharya, Sarbari; Ananthamurthy, Sharath

    2016-01-20

    We have studied in detail the situation wherein two microbeads are trapped axially in a single-beam Gaussian intensity profile optical trap. We find that the corner frequency extracted from a power spectral density analysis of intensity fluctuations recorded on a quadrant photodetector (QPD) is dependent on the detection scheme. Using forward- and backscattering detection schemes with single and two laser wavelengths along with computer simulations, we conclude that fluctuations detected in backscattering bear true position information of the bead encountered first in the beam propagation direction. Forward scattering, on the other hand, carries position information of both beads with substantial contribution from the bead encountered first along the beam propagation direction. Mie scattering analysis further reveals that the interference term from the scattering of the two beads contributes significantly to the signal, precluding the ability to resolve the positions of the individual beads in forward scattering. In QPD-based detection schemes, detection through backscattering, thereby, is imperative to track the true displacements of axially trapped microbeads for possible studies on light-mediated interbead interactions. PMID:26835934

  14. Microdosimetric spectra and LET distributions on board the Mir station obtained with a particle track detector

    International Nuclear Information System (INIS)

    A spectrometer measuring energy lost (?E) was used to determine linear energy transfer (LET) spectra on board the Mir orbital station during the period from 8 October 1997 to 16 June 2000, i.e. during the 24th, 26th, 27th and 28th basic expeditions. It was found that the LET spectra of secondary particles between 10 and 700 keV.μm-1 in tissue do not depend on the external radiator, with the average quality factors for the region mentioned being about 6.4 with ICRP 26 quality factors or about 7.4 with ICRP 60 quality factors. Both differential and integral LET spectra are presented for some typical cases. The spectra permitted us to calculate the total doses and dose equivalents due to particles with the LET values in the mentioned region. It was found that these doses are higher when the detector was placed in a less shielded area. It was also found that these doses vary from one expedition to another. The correlation of these variations with the solar activity level was studied. (author)

  15. Confined Diffusion Without Fences of a G-Protein-Coupled Receptor as Revealed by Single Particle Tracking

    Science.gov (United States)

    Daumas, Frédéric; Destainville, Nicolas; Millot, Claire; Lopez, André; Dean, David; Salomé, Laurence

    2003-01-01

    Single particle tracking is a powerful tool for probing the organization and dynamics of the plasma membrane constituents. We used this technique to study the μ-opioid receptor belonging to the large family of the G-protein-coupled receptors involved with other partners in a signal transduction pathway. The specific labeling of the receptor coupled to a T7-tag at its N-terminus, stably expressed in fibroblastic cells, was achieved by colloidal gold coupled to a monoclonal anti T7-tag antibody. The lateral movements of the particles were followed by nanovideomicroscopy at 40 ms time resolution during 2 min with a spatial precision of 15 nm. The receptors were found to have either a slow or directed diffusion mode (10%) or a walking confined diffusion mode (90%) composed of a long-term random diffusion and a short-term confined diffusion, and corresponding to a diffusion confined within a domain that itself diffuses. The results indicate that the confinement is due to an effective harmonic potential generated by long-range attraction between the membrane proteins. A simple model for interacting membrane proteins diffusion is proposed that explains the variations with the domain size of the short-term and long-term diffusion coefficients. PMID:12524289

  16. A New Numerical Approach to Evaluate Variation of Electric Field Strength at the End of Particle Trajectory in Nuclear Track Detectors

    International Nuclear Information System (INIS)

    A geometrical model for an electrochemical etching (ECE) track in a dielectric detector is defined and a primary programme is written to generate the track. The generated track is transformed to an M × N matrix of primary voltages. Using a numerical method, the matrix of final voltages is computed, and using another numerical approach, the electric field strengths in the elements of detector volume are computed. The final field strength at the end of particle trajectory is obtained. The results of our numerical computation show that there are exact correlations between the field strength at the end of particle trajectory and the parameters of track under ECE. It is found that although two traditional models of Mason and Smythe in dielectrics can be partly applied for short and long tracks, none of them are able to explain the behaviour of field strength in a 'general case'. Furthermore, we find that there is an expressive relationship between the field strength and the incidence angle of impacted particle, while the mentioned traditional models are not able to explain this effect

  17. Normalized and Asynchronous Mirror Alignment for Cherenkov Telescopes

    CERN Document Server

    Ahnen, M L; Balbo, M; Bergmann, M; Biland, A; Blank, M; Bretz, T; Bruegge, K A; Buss, J; Domke, M; Dorner, D; Einecke, S; Hempfling, C; Hildebrand, D; Hughes, G; Lustermann, W; Mannheim, K; Mueller, S A; Neise, D; Neronov, A; Noethe, M; Overkemping, A -K; Paravac, A; Pauss, F; Rhode, W; Shukla, A; Temme, F; Thaele, J; Toscano, S; Vogler, P; Walter, R; Wilbert, A

    2016-01-01

    Imaging Atmospheric Cherenkov Telescopes (IACTs) need imaging optics with large apertures and high image intensities to map the faint Cherenkov light emitted from cosmic ray air showers onto their image sensors. Segmented reflectors fulfill these needs, and as they are composed from mass production mirror facets they are inexpensive and lightweight. However, as the overall image is a superposition of the individual facet images, alignment is a challenge. Here we present a computer vision based star tracking alignment method, which also works for limited or changing star light visibility. Our method normalizes the mirror facet reflection intensities to become independent of the reference star's intensity or the cloud coverage. Using two CCD cameras, our method records the mirror facet orientations asynchronously of the telescope drive system, and thus makes the method easy to integrate into existing telescopes. It can be combined with remote facet actuation, but does not require one to work. Furthermore, it ca...

  18. Calculation of RBE for normal tissue complications based on charged particle track structure

    International Nuclear Information System (INIS)

    A new approach for the calculation of RBE for normal tissue complications after charged particle and neutron irradiation is discussed. It is based on the extension of a model originally developed for the application to cell survival. It can be shown, that according to the model RBE values are determined largely by the α/β-ratio of the photon dose response curve, but are expected to be nearly independent of the absolute values of α and β. Thus, the model can be applied to normal tissue complications as well, where α/β-ratios can be determined by means of fractionation experiments. Agreement of model predictions and experimental results obtained in animal experiments confirm the appliability of the model even in the case of complex biological endpoints. (orig.)

  19. TRACKING AND MONITORING OF TAGGED OBJECTS EMPLOYING PARTICLE SWARM OPTIMIZATION ALGORITHM IN A DEPARTMENTAL STORE

    Directory of Open Access Journals (Sweden)

    Indrajit Bhattacharya

    2011-05-01

    Full Text Available The present paper proposes a departmental store automation system based on Radio Frequency Identification (RFID technology and Particle Swarm Optimization (PSO algorithm. The items in the departmental store spanned over different sections and in multiple floors, are tagged with passive RFID tags. The floor is divided into number of zones depending on different types of items that are placed in their respective racks. Each of the zones is placed with one RFID reader, which constantly monitors the items in their zone and periodically sends that information to the application. The problem of systematic periodic monitoring of the store is addressed in this application so that the locations, distributions and demands of every item in the store can be invigilated with intelligence. The proposed application is successfully demonstrated on a simulated case study.

  20. Comparison of bulk and epitaxial 4H-SiC detectors for radiation hard particle tracking

    CERN Document Server

    Quinn, T; Bruzzi, M; Cunningham, W; Mathieson, K; Moll, M; Nelson, T; Nilsson, H E; Pintillie, I; Rahman, M; Reynolds, L; Sciortino, S; Sellin, P J; Strachan, H; Svensson, B G; Vaitkus, J

    2003-01-01

    Measurements and simulations have been carried out using bulk and epitaxial SiC detectors. Samples were irradiated to fluences of around 10**1**4 hardrons/cm**2. Material of thickness 40um gave a charge collection efficiency of 100% dropping to around 60% at 100mum thickness. Detailed MEDICI simulations incorporated the main defect levels in SiC, the vanadium center, Z-center and a mid-gap level as measured by deep level transient spectroscopy and other techniques. Calculated recombination currents and charge collection efficiencies at varying fluences were comparable to experimental data. The study suggests that SiC detectors will operate up to fluences around 10 **1**6/cm**2 as required by future particle physics experiments.