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Sample records for advanced particle filters

  1. Westinghouse Advanced Particle Filter System

    SciTech Connect

    Lippert, T.E.; Bruck, G.J.; Sanjana, Z.N.; Newby, R.A.; Bachovchin, D.M.

    1996-12-31

    Integrated Gasification Combined Cycles (IGCC) and Pressurized Fluidized Bed Combustion (PFBC) are being developed and demonstrated for commercial, power generation application. Hot gas particulate filters are key components for the successful implementation of IGCC and PFBC in power generation gas turbine cycles. The objective of this work is to develop and qualify through analysis and testing a practical hot gas ceramic barrier filter system that meets the performance and operational requirements of PFBC and IGCC systems. This paper reports on the development and status of testing of the Westinghouse Advanced Hot Gas Particle Filter (W-APF) including: W-APF integrated operation with the American Electric Power, 70 MW PFBC clean coal facility--approximately 6000 test hours completed; approximately 2500 hours of testing at the Hans Ahlstrom 10 MW PCFB facility located in Karhula, Finland; over 700 hours of operation at the Foster Wheeler 2 MW 2nd generation PFBC facility located in Livingston, New Jersey; status of Westinghouse HGF supply for the DOE Southern Company Services Power System Development Facility (PSDF) located in Wilsonville, Alabama; the status of the Westinghouse development and testing of HGF`s for Biomass Power Generation; and the status of the design and supply of the HGF unit for the 95 MW Pinon Pine IGCC Clean Coal Demonstration.

  2. Advanced particle filter. Technical progress report No. 19, January 1995--March 1995

    SciTech Connect

    1995-08-01

    Tidd advanced particle filtration (APF) test runs 25 through 34 were completed during the first quarter of 1995. All Tidd testing was completed with the conclusion of APF test run 34 on 3/30/95. The Westinghouse activities supporting the APF operation during this quarter included processing of test data and participating in one APF borescope inspection. Data is included on the filter operation.

  3. Incorporating advanced language models into the P300 speller using particle filtering

    NASA Astrophysics Data System (ADS)

    Speier, W.; Arnold, C. W.; Deshpande, A.; Knall, J.; Pouratian, N.

    2015-08-01

    Objective. The P300 speller is a common brain-computer interface (BCI) application designed to communicate language by detecting event related potentials in a subject’s electroencephalogram signal. Information about the structure of natural language can be valuable for BCI communication, but attempts to use this information have thus far been limited to rudimentary n-gram models. While more sophisticated language models are prevalent in natural language processing literature, current BCI analysis methods based on dynamic programming cannot handle their complexity. Approach. Sampling methods can overcome this complexity by estimating the posterior distribution without searching the entire state space of the model. In this study, we implement sequential importance resampling, a commonly used particle filtering (PF) algorithm, to integrate a probabilistic automaton language model. Main result. This method was first evaluated offline on a dataset of 15 healthy subjects, which showed significant increases in speed and accuracy when compared to standard classification methods as well as a recently published approach using a hidden Markov model (HMM). An online pilot study verified these results as the average speed and accuracy achieved using the PF method was significantly higher than that using the HMM method. Significance. These findings strongly support the integration of domain-specific knowledge into BCI classification to improve system performance.

  4. Incorporating advanced language models into the P300 speller using particle filtering

    PubMed Central

    Speier, W; Arnold, CW; Deshpande, A; Knall, J

    2015-01-01

    Objective The P300 speller is a common brain–computer interface (BCI) application designed to communicate language by detecting event related potentials in a subject’s electroencephalogram (EEG) signal. Information about the structure of natural language can be valuable for BCI communication, but attempts to use this information have thus far been limited to rudimentary n-gram models. While more sophisticated language models are prevalent in natural language processing literature, current BCI analysis methods based on dynamic programming cannot handle their complexity. Approach Sampling methods can overcome this complexity by estimating the posterior distribution without searching the entire state space of the model. In this study, we implement sequential importance resampling, a commonly used particle filtering (PF) algorithm, to integrate a probabilistic automaton language model. Main Result This method was first evaluated offline on a dataset of 15 healthy subjects, which showed significant increases in speed and accuracy when compared to standard classification methods as well as a recently published approach using a hidden Markov model (HMM). An online pilot study verified these results as the average speed and accuracy achieved using the PF method was significantly higher than that using the HMM method. Significance These findings strongly support the integration of domain-specific knowledge into BCI classification to improve system performance. PMID:26061188

  5. ADVANCED HOT GAS FILTER DEVELOPMENT

    SciTech Connect

    E.S. Connolly; G.D. Forsythe

    1998-12-22

    Advanced, coal-based power plants will require durable and reliable hot gas filtration systems to remove particulate contaminants from the gas streams to protect downstream components such as turbine blades from erosion damage. It is expected that the filter elements in these systems will have to be made of ceramic materials to withstand goal service temperatures of 1600 F or higher. Recent demonstration projects and pilot plant tests have indicated that the current generation of ceramic hot gas filters (cross-flow and candle configurations) are failing prematurely. Two of the most promising materials that have been extensively evaluated are clay-bonded silicon carbide and alumina-mullite porous monoliths. These candidates, however, have been found to suffer progressive thermal shock fatigue damage, as a result of rapid cooling/heating cycles. Such temperature changes occur when the hot filters are back-pulsed with cooler gas to clean them, or in process upset conditions, where even larger gas temperature changes may occur quickly and unpredictably. In addition, the clay-bonded silicon carbide materials are susceptible to chemical attack of the glassy binder phase that holds the SiC particles together, resulting in softening, strength loss, creep, and eventual failure.

  6. OPTIMIZATION OF ADVANCED FILTER SYSTEMS

    SciTech Connect

    R.A. Newby; M.A. Alvin; G.J. Bruck; T.E. Lippert; E.E. Smeltzer; M.E. Stampahar

    2002-06-30

    Two advanced, hot gas, barrier filter system concepts have been proposed by the Siemens Westinghouse Power Corporation to improve the reliability and availability of barrier filter systems in applications such as PFBC and IGCC power generation. The two hot gas, barrier filter system concepts, the inverted candle filter system and the sheet filter system, were the focus of bench-scale testing, data evaluations, and commercial cost evaluations to assess their feasibility as viable barrier filter systems. The program results show that the inverted candle filter system has high potential to be a highly reliable, commercially successful, hot gas, barrier filter system. Some types of thin-walled, standard candle filter elements can be used directly as inverted candle filter elements, and the development of a new type of filter element is not a requirement of this technology. Six types of inverted candle filter elements were procured and assessed in the program in cold flow and high-temperature test campaigns. The thin-walled McDermott 610 CFCC inverted candle filter elements, and the thin-walled Pall iron aluminide inverted candle filter elements are the best candidates for demonstration of the technology. Although the capital cost of the inverted candle filter system is estimated to range from about 0 to 15% greater than the capital cost of the standard candle filter system, the operating cost and life-cycle cost of the inverted candle filter system is expected to be superior to that of the standard candle filter system. Improved hot gas, barrier filter system availability will result in improved overall power plant economics. The inverted candle filter system is recommended for continued development through larger-scale testing in a coal-fueled test facility, and inverted candle containment equipment has been fabricated and shipped to a gasifier development site for potential future testing. Two types of sheet filter elements were procured and assessed in the program

  7. Advances in Collaborative Filtering

    NASA Astrophysics Data System (ADS)

    Koren, Yehuda; Bell, Robert

    The collaborative filtering (CF) approach to recommenders has recently enjoyed much interest and progress. The fact that it played a central role within the recently completed Netflix competition has contributed to its popularity. This chapter surveys the recent progress in the field. Matrix factorization techniques, which became a first choice for implementing CF, are described together with recent innovations. We also describe several extensions that bring competitive accuracy into neighborhood methods, which used to dominate the field. The chapter demonstrates how to utilize temporal models and implicit feedback to extend models accuracy. In passing, we include detailed descriptions of some the central methods developed for tackling the challenge of the Netflix Prize competition.

  8. Advanced simulation of digital filters

    NASA Astrophysics Data System (ADS)

    Doyle, G. S.

    1980-09-01

    An Advanced Simulation of Digital Filters has been implemented on the IBM 360/67 computer utilizing Tektronix hardware and software. The program package is appropriate for use by persons beginning their study of digital signal processing or for filter analysis. The ASDF programs provide the user with an interactive method by which filter pole and zero locations can be manipulated. Graphical output on both the Tektronix graphics screen and the Versatec plotter are provided to observe the effects of pole-zero movement.

  9. Gaussian particle flow implementation of PHD filter

    NASA Astrophysics Data System (ADS)

    Zhao, Lingling; Wang, Junjie; Li, Yunpeng; Coates, Mark J.

    2016-05-01

    Particle filter and Gaussian mixture implementations of random finite set filters have been proposed to tackle the issue of jointly estimating the number of targets and their states. The Gaussian mixture PHD (GM-PHD) filter has a closed-form expression for the PHD for linear and Gaussian target models, and extensions using the extended Kalman filter or unscented Kalman Filter have been developed to allow the GM-PHD filter to accommodate mildly nonlinear dynamics. Errors resulting from linearization or model mismatch are unavoidable. A particle filter implementation of the PHD filter (PF-PHD) is more suitable for nonlinear and non-Gaussian target models. The particle filter implementations are much more computationally expensive and performance can suffer when the proposal distribution is not a good match to the posterior. In this paper, we propose a novel implementation of the PHD filter named the Gaussian particle flow PHD filter (GPF-PHD). It employs a bank of particle flow filters to approximate the PHD; these play the same role as the Gaussian components in the GM-PHD filter but are better suited to non-linear dynamics and measurement equations. Using the particle flow filter allows the GPF-PHD filter to migrate particles to the dense regions of the posterior, which leads to higher efficiency than the PF-PHD. We explore the performance of the new algorithm through numerical simulations.

  10. Advanced Petroleum-Based Fuels - Diesel Emissions Project (APBF-DEC): 2,000-Hour Performance of a NOx Adsorber Catalyst and Diesel Particle Filter System for a Medium-Duty, Pick-Up Diesel Engine Platform; Final Report

    SciTech Connect

    Not Available

    2007-03-01

    Presents the results of a 2,000-hour test of an emissions control system consisting of a nitrogen oxides adsorber catalyst in combination with a diesel particle filter, advanced fuels, and advanced engine controls in an SUV/pick-up truck vehicle platform.

  11. ADVANCED HOT GAS FILTER DEVELOPMENT

    SciTech Connect

    E.S. Connolly; G.D. Forsythe

    2000-09-30

    DuPont Lanxide Composites, Inc. undertook a sixty-month program, under DOE Contract DEAC21-94MC31214, in order to develop hot gas candle filters from a patented material technology know as PRD-66. The goal of this program was to extend the development of this material as a filter element and fully assess the capability of this technology to meet the needs of Pressurized Fluidized Bed Combustion (PFBC) and Integrated Gasification Combined Cycle (IGCC) power generation systems at commercial scale. The principal objective of Task 3 was to build on the initial PRD-66 filter development, optimize its structure, and evaluate basic material properties relevant to the hot gas filter application. Initially, this consisted of an evaluation of an advanced filament-wound core structure that had been designed to produce an effective bulk filter underneath the barrier filter formed by the outer membrane. The basic material properties to be evaluated (as established by the DOE/METC materials working group) would include mechanical, thermal, and fracture toughness parameters for both new and used material, for the purpose of building a material database consistent with what is being done for the alternative candle filter systems. Task 3 was later expanded to include analysis of PRD-66 candle filters, which had been exposed to actual PFBC conditions, development of an improved membrane, and installation of equipment necessary for the processing of a modified composition. Task 4 would address essential technical issues involving the scale-up of PRD-66 candle filter manufacturing from prototype production to commercial scale manufacturing. The focus would be on capacity (as it affects the ability to deliver commercial order quantities), process specification (as it affects yields, quality, and costs), and manufacturing systems (e.g. QA/QC, materials handling, parts flow, and cost data acquisition). Any filters fabricated during this task would be used for product qualification tests

  12. System and Apparatus for Filtering Particles

    NASA Technical Reports Server (NTRS)

    Agui, Juan H. (Inventor); Vijayakumar, Rajagopal (Inventor)

    2015-01-01

    A modular pre-filtration apparatus may be beneficial to extend the life of a filter. The apparatus may include an impactor that can collect a first set of particles in the air, and a scroll filter that can collect a second set of particles in the air. A filter may follow the pre-filtration apparatus, thus causing the life of the filter to be increased.

  13. Advanced development of the nested fiber filter

    SciTech Connect

    Litt, R.D.; Glover, R.C.; Raghavan, J.K.

    1993-05-01

    Battelle and DOE have been developing the Nested Fiber Filter for high-temperature, high-pressure particulate control as applied to advanced coal-fired power systems. The current program represents a focused effort to develop cleaning techniques for the NFF at pilot plant scale. The filter consists of a 10-inch deep nest of stainless steel fibers collecting particles as dendrites on individual fibers. Tests with a 6-sq ft Nested Fiber Filter (NFF) have demonstrated greater than 99% particulate capture over a limited number of operating hours. Design, development, and testing a 6-sq ft module proceeded in three sequential stages. The NFF test module was integrated with a fluidized bed combustor to provide a realistic particulate laden gas to the NFF. Initial problems with gas and particulate bypassing plus ineffective cleaning by acoustic drivers led to a series of tests on a 1.5 sq ft section of the NFF. The fiber bed was slightly compressed to further prevent voids forming at the side walls during the vibration cleaning cycle. A mechanical vibrator was coupled with the pulse combustor to effectively clean/regenerate the NFF over a limited number of cycles. Testing resumed with the 6-sq ft test module and the above modifications. Two tests totaling 15 hours of operation and 14 repetitive cycles are summarized here and demonstrated the NFF performance. The preliminary engineering and economic evaluation showed the NFF to be cost-competitive with the ceramic cross-flow filter and the granular bed filter. Capital cost for a NFF on a 330 MW PFBC is estimated to be $42.9 million or $130/kW. The total plant cost for a PFBC system including the NFF is estimated to be $1,274/kW. This compares to $1,261/kW for a PFBC plus ceramic cross-flow filter or $1,351/kW for a PFBC plus granular bed filter.

  14. Angle only tracking with particle flow filters

    NASA Astrophysics Data System (ADS)

    Daum, Fred; Huang, Jim

    2011-09-01

    We show the results of numerical experiments for tracking ballistic missiles using only angle measurements. We compare the performance of an extended Kalman filter with a new nonlinear filter using particle flow to compute Bayes' rule. For certain difficult geometries, the particle flow filter is an order of magnitude more accurate than the EKF. Angle only tracking is of interest in several different sensors; for example, passive optics and radars in which range and Doppler data are spoiled by jamming.

  15. Groupwise surface correspondence using particle filtering

    NASA Astrophysics Data System (ADS)

    Li, Guangxu; Kim, Hyoungseop; Tan, Joo Kooi; Ishikawa, Seiji

    2015-03-01

    To obtain an effective interpretation of organic shape using statistical shape models (SSMs), the correspondence of the landmarks through all the training samples is the most challenging part in model building. In this study, a coarse-tofine groupwise correspondence method for 3-D polygonal surfaces is proposed. We manipulate a reference model in advance. Then all the training samples are mapped to a unified spherical parameter space. According to the positions of landmarks of the reference model, the candidate regions for correspondence are chosen. Finally we refine the perceptually correct correspondences between landmarks using particle filter algorithm, where the likelihood of local surface features are introduced as the criterion. The proposed method was performed on the correspondence of 9 cases of left lung training samples. Experimental results show the proposed method is flexible and under-constrained.

  16. Particle filtering for passive fathometer tracking.

    PubMed

    Michalopoulou, Zoi-Heleni; Yardim, Caglar; Gerstoft, Peter

    2012-01-01

    Seabed interface depths and fathometer amplitudes are tracked for an unknown and changing number of sub-bottom reflectors. This is achieved by incorporating conventional and adaptive fathometer processors into sequential Monte Carlo methods for a moving vertical line array. Sediment layering information and time-varying fathometer response amplitudes are tracked by using a multiple model particle filter with an uncertain number of reflectors. Results are compared to a classical particle filter where the number of reflectors is considered to be known. Reflector tracking is demonstrated for both conventional and adaptive processing applied to the drifting array data from the Boundary 2003 experiment. The layering information is successfully tracked by the multiple model particle filter even for noisy fathometer outputs.

  17. Advanced Filter Technology For Nuclear Thermal Propulsion

    NASA Technical Reports Server (NTRS)

    Castillon, Erick

    2015-01-01

    The Scrubber System focuses on using HEPA filters and carbon filtration to purify the exhaust of a Nuclear Thermal Propulsion engine of its aerosols and radioactive particles; however, new technology may lend itself to alternate filtration options, which may lead to reduction in cost while at the same time have the same filtering, if not greater, filtering capabilities, as its predecessors. Extensive research on various types of filtration methods was conducted with only four showing real promise: ionization, cyclonic separation, classic filtration, and host molecules. With the four methods defined, more research was needed to find the devices suitable for each method. Each filtration option was matched with a device: cyclonic separators for the method of the same name, electrostatic separators for ionization, HEGA filters, and carcerands for the host molecule method. Through many hours of research, the best alternative for aerosol filtration was determined to be the electrostatic precipitator because of its high durability against flow rate and its ability to cleanse up to 99.99% of contaminants as small as 0.001 micron. Carcerands, which are the only alternative to filtering radioactive particles, were found to be non-existent commercially because of their status as a "work in progress" at research institutions. Nevertheless, the conclusions after the research were that HEPA filters is recommended as the best option for filtering aerosols and carbon filtration is best for filtering radioactive particles.

  18. ADVANCED HOT GAS FILTER DEVELOPMENT

    SciTech Connect

    RICHARD A. WAGNER

    1998-09-04

    This report describes the fabrication and testing of continuous fiber ceramic composite (CFCC) based hot gas filters. The fabrication approach utilized a modified filament winding method that combined both continuous and chopped fibers into a novel microstructure. The work was divided into five primary tasks. In the first task, a preliminary set of compositions was fabricated in the form of open end tubes and characterized. The results of this task were used to identify the most promising compositions for sub-scale filter element fabrication and testing. In addition to laboratory measurements of permeability and strength, exposure testing in a coal combustion environment was performed to asses the thermo-chemical stability of the CFCC materials. Four candidate compositions were fabricated into sub-scale filter elements with integral flange and a closed end. Following the 250 hour exposure test in a circulating fluid bed combustor, the retained strength ranged from 70 t 145 percent of the as-fabricated strength. The post-test samples exhibited non-catastrophic failure behavior in contrast to the brittle failure exhibited by monolithic materials. Filter fabrication development continued in a filter improvement and cost reduction task that resulted in an improved fiber architecture, the production of a net shape flange, and an improved low cost bond. These modifications were incorporated into the process and used to fabricate 50 full-sized filter elements for testing in demonstration facilities in Karhula, Finland and at the Power Systems Development Facility (PSDF) in Wilsonville, AL. After 581 hours of testing in the Karhula facility, the elements retained approximately 87 percent of their as-fabricated strength. In addition, mechanical response testing at Virginia Tech provided a further demonstration of the high level of strain tolerance of the vacuum wound filter elements. Additional testing in the M. W. Kellogg unit at the PSDF has accumulated over 1800 hours of

  19. Quantitative filter forensics for indoor particle sampling.

    PubMed

    Haaland, D; Siegel, J A

    2017-03-01

    Filter forensics is a promising indoor air investigation technique involving the analysis of dust which has collected on filters in central forced-air heating, ventilation, and air conditioning (HVAC) or portable systems to determine the presence of indoor particle-bound contaminants. In this study, we summarize past filter forensics research to explore what it reveals about the sampling technique and the indoor environment. There are 60 investigations in the literature that have used this sampling technique for a variety of biotic and abiotic contaminants. Many studies identified differences between contaminant concentrations in different buildings using this technique. Based on this literature review, we identified a lack of quantification as a gap in the past literature. Accordingly, we propose an approach to quantitatively link contaminants extracted from HVAC filter dust to time-averaged integrated air concentrations. This quantitative filter forensics approach has great potential to measure indoor air concentrations of a wide variety of particle-bound contaminants. Future studies directly comparing quantitative filter forensics to alternative sampling techniques are required to fully assess this approach, but analysis of past research suggests the enormous possibility of this approach.

  20. ADVANCED HOT GAS FILTER DEVELOPMENT

    SciTech Connect

    Matthew R. June; John L. Hurley; Mark W. Johnson

    1999-04-01

    Iron aluminide hot gas filters have been developed using powder metallurgy techniques to form seamless cylinders. Three alloys were short-term corrosion tested in simulated IGCC atmospheres with temperatures between 925 F and 1200 F with hydrogen sulfide concentrations ranging from 783 ppm{sub v} to 78,300 ppm{sub v}. Long-term testing was conducted for 1500 hours at 925 F with 78,300 ppm{sub v}. The FAS and FAL alloys were found to be corrosion resistant in the simulated environments. The FAS alloy has been commercialized.

  1. Analyzing Meteoroid Flights Using Particle Filters

    NASA Astrophysics Data System (ADS)

    Sansom, E. K.; Rutten, M. G.; Bland, P. A.

    2017-02-01

    Fireball observations from camera networks provide position and time information along the trajectory of a meteoroid that is transiting our atmosphere. The complete dynamical state of the meteoroid at each measured time can be estimated using Bayesian filtering techniques. A particle filter is a novel approach to modeling the uncertainty in meteoroid trajectories and incorporates errors in initial parameters, the dynamical model used, and observed position measurements. Unlike other stochastic approaches, a particle filter does not require predefined values for initial conditions or unobservable trajectory parameters. The Bunburra Rockhole fireball, observed by the Australian Desert Fireball Network (DFN) in 2007, is used to determine the effectiveness of a particle filter for use in fireball trajectory modeling. The final mass is determined to be 2.16+/- 1.33 {kg} with a final velocity of 6030+/- 216 {{m}} {{{s}}}-1, similar to previously calculated values. The full automatability of this approach will allow an unbiased evaluation of all events observed by the DFN and lead to a better understanding of the dynamical state and size frequency distribution of asteroid and cometary debris in the inner solar system.

  2. ADVANCED SECOND GENERATION CERAMIC CANDLE FILTERS

    SciTech Connect

    M.A. Alvin

    2002-01-31

    Through sponsorship from the Department of Energy's National Energy Technology Laboratory (DOE/NETL), development and manufacture of advanced second generation candle filters was undertaken in the early 1990's. Efforts were primarily focused on the manufacture of fracture toughened, 1.5 m, continuous fiber ceramic composite (CFCC) and filament wound candle filters by 3M, McDermott, DuPont Lanxide Composites, and Techniweave. In order to demonstrate long-term thermal, chemical, and mechanical stability of the advanced second generation candle filter materials, Siemens Westinghouse initiated high temperature, bench-scale, corrosion testing of 3M's CVI-SiC and DuPont's PRD-66 mini-candles, and DuPont's CFCC SiC-SiC and IF&P Fibrosic{sup TM} coupons under simulated, pressurized fluidized-bed combustion (PFBC) conditions. This effort was followed by an evaluation of the mechanical and filtration performance of the advanced second generation filter elements in Siemens Westinghouse's bench-scale PFBC test facility in Pittsburgh, Pennsylvania. Arrays of 1.4-1.5 m 3M CVI-SiC, DuPont PRD-66, DuPont SiC-SiC, and IF&P Fibrosic{sup TM} candles were subjected to steady state process operating conditions, increased severity thermal transients, and accelerated pulse cycling test campaigns which represented {approx}1760 hours of equivalent filter operating life. Siemens Westinghouse subsequently participated in early material surveillance programs which marked entry of the 3M CVI-SiC and DuPont PRD-66 candle filters in Siemens Westinghouse Advanced Particulate Filtration (APF) system at the American Electric Power (AEP) Tidd Demonstration Plant in Brilliant, Ohio. Siemens Westinghouse then conducted an extended, accelerated life, qualification program, evaluating the performance of the 3M, McDermott, and Techniweave oxide-based CFCC filter elements, modified DuPont PRD-66 elements, and the Blasch, Scapa Cerafil{sup TM}, and Specific Surface monolithic candles for use in the APF

  3. Advanced Bragg grating filters for DWDM applications

    NASA Astrophysics Data System (ADS)

    Sokolov, Victor I.; Khudobenko, Alexander I.; Panchenko, Vladislav Y.

    2002-09-01

    The advent of the technology of Dense Wavelength Division Multiplexing (DWDM) in Optical Fiber Networks (OFNs) has resulted in the necessity of developing advanced Optical Add/Drop Multiplexers (OADMs) on the basis of submicron Bragg gratings. The OADMs for dense multichannel OFNs with bit rates 10 - 40 Gbits/s per channel and channel spacing 200, 100 and 50 GHz must possess rectangular-shaped reflection/transmission spectra and linear phase characteristic within the stop/passband. These features can not be achieved with uniform periodic Bragg gratings and therefore nonuniform gratings with space-modulated coupling coefficient should be used. We present the recent advances in the design and fabrication of narrowband wavelength-selective optical filters for DWDM applications on the basis of single-mode fibers with side-polishing and periodic relief Bragg gratings with apodized coupling coefficient. The peculiarities of propagation, interaction and diffraction of electromagnetic waves in nonuniform Bragg grating structures are considered. Narrowband reflection filters based on side-polished fibers and submicron relief gratings on SiO2 and SiO materials are designed and fabricated. The filters have stopband width 0.4 - 0.8 nm and peak reflectivity R > 98% in the 1.55 mkm wavelength communication region. Narrowband flat-top reflection filters for DWDM applications based on side-polished fibers and periodic relief Bragg gratings are designed. The schemes for multichannel integration of Bragg grating filters into OFNs are presented.

  4. Towards robust particle filters for high-dimensional systems

    NASA Astrophysics Data System (ADS)

    van Leeuwen, Peter Jan

    2015-04-01

    In recent years particle filters have matured and several variants are now available that are not degenerate for high-dimensional systems. Often they are based on ad-hoc combinations with Ensemble Kalman Filters. Unfortunately it is unclear what approximations are made when these hybrids are used. The proper way to derive particle filters for high-dimensional systems is exploring the freedom in the proposal density. It is well known that using an Ensemble Kalman Filter as proposal density (the so-called Weighted Ensemble Kalman Filter) does not work for high-dimensional systems. However, much better results are obtained when weak-constraint 4Dvar is used as proposal, leading to the implicit particle filter. Still this filter is degenerate when the number of independent observations is large. The Equivalent-Weights Particle Filter is a filter that works well in systems of arbitrary dimensions, but it contains a few tuning parameters that have to be chosen well to avoid biases. In this paper we discuss ways to derive more robust particle filters for high-dimensional systems. Using ideas from large-deviation theory and optimal transportation particle filters will be generated that are robust and work well in these systems. It will be shown that all successful filters can be derived from one general framework. Also, the performance of the filters will be tested on simple but high-dimensional systems, and, if time permits, on a high-dimensional highly nonlinear barotropic vorticity equation model.

  5. State estimation and prediction using clustered particle filters

    PubMed Central

    Lee, Yoonsang; Majda, Andrew J.

    2016-01-01

    Particle filtering is an essential tool to improve uncertain model predictions by incorporating noisy observational data from complex systems including non-Gaussian features. A class of particle filters, clustered particle filters, is introduced for high-dimensional nonlinear systems, which uses relatively few particles compared with the standard particle filter. The clustered particle filter captures non-Gaussian features of the true signal, which are typical in complex nonlinear dynamical systems such as geophysical systems. The method is also robust in the difficult regime of high-quality sparse and infrequent observations. The key features of the clustered particle filtering are coarse-grained localization through the clustering of the state variables and particle adjustment to stabilize the method; each observation affects only neighbor state variables through clustering and particles are adjusted to prevent particle collapse due to high-quality observations. The clustered particle filter is tested for the 40-dimensional Lorenz 96 model with several dynamical regimes including strongly non-Gaussian statistics. The clustered particle filter shows robust skill in both achieving accurate filter results and capturing non-Gaussian statistics of the true signal. It is further extended to multiscale data assimilation, which provides the large-scale estimation by combining a cheap reduced-order forecast model and mixed observations of the large- and small-scale variables. This approach enables the use of a larger number of particles due to the computational savings in the forecast model. The multiscale clustered particle filter is tested for one-dimensional dispersive wave turbulence using a forecast model with model errors. PMID:27930332

  6. A backtracking algorithm that deals with particle filter degeneracy

    NASA Astrophysics Data System (ADS)

    Baarsma, Rein; Schmitz, Oliver; Karssenberg, Derek

    2016-04-01

    Particle filters are an excellent way to deal with stochastic models incorporating Bayesian data assimilation. While they are computationally demanding, the particle filter has no problem with nonlinearity and it accepts non-Gaussian observational data. In the geoscientific field it is this computational demand that creates a problem, since dynamic grid-based models are often already quite computationally demanding. As such it is of the utmost importance to keep the amount of samples in the filter as small as possible. Small sample populations often lead to filter degeneracy however, especially in models with high stochastic forcing. Filter degeneracy renders the sample population useless, as the population is no longer statistically informative. We have created an algorithm in an existing data assimilation framework that reacts to and deals with filter degeneracy based on Spiller et al. [2008]. During the Bayesian updating step of the standard particle filter, the algorithm tests the sample population for filter degeneracy. If filter degeneracy has occurred, the algorithm resets to the last time the filter did work correctly and recalculates the failed timespan of the filter with an increased sample population. The sample population is then reduced to its original size and the particle filter continues as normal. This algorithm was created in the PCRaster Python framework, an open source tool that enables spatio-temporal forward modelling in Python [Karssenberg et al., 2010] . The framework already contains several data assimilation algorithms, including a standard particle filter and a Kalman filter. The backtracking particle filter algorithm has been added to the framework, which will make it easy to implement in other research. The performance of the backtracking particle filter is tested against a standard particle filter using two models. The first is a simple nonlinear point model, and the second is a more complex geophysical model. The main testing

  7. Blended particle filters for large-dimensional chaotic dynamical systems.

    PubMed

    Majda, Andrew J; Qi, Di; Sapsis, Themistoklis P

    2014-05-27

    A major challenge in contemporary data science is the development of statistically accurate particle filters to capture non-Gaussian features in large-dimensional chaotic dynamical systems. Blended particle filters that capture non-Gaussian features in an adaptively evolving low-dimensional subspace through particles interacting with evolving Gaussian statistics on the remaining portion of phase space are introduced here. These blended particle filters are constructed in this paper through a mathematical formalism involving conditional Gaussian mixtures combined with statistically nonlinear forecast models compatible with this structure developed recently with high skill for uncertainty quantification. Stringent test cases for filtering involving the 40-dimensional Lorenz 96 model with a 5-dimensional adaptive subspace for nonlinear blended filtering in various turbulent regimes with at least nine positive Lyapunov exponents are used here. These cases demonstrate the high skill of the blended particle filter algorithms in capturing both highly non-Gaussian dynamical features as well as crucial nonlinear statistics for accurate filtering in extreme filtering regimes with sparse infrequent high-quality observations. The formalism developed here is also useful for multiscale filtering of turbulent systems and a simple application is sketched below.

  8. Advanced astronomical interference filters from SCHOTT technology

    NASA Astrophysics Data System (ADS)

    Hull, Anthony B.; Reichel, Steffen; Brauneck, Ulf; Bourquin, Sebastien; Marin-Franch, Antoni

    2016-01-01

    Developing precision interference filters for astronomical radiometry often requires simultaneous solutions to very difficult requirements. SCHOTT's 80-year legacy methods with interference filters and 9,200-m2 facility dedicated to filters and optical fabrication bring multiple disciplines together to simultaneously solve requirements that include: narrow-band high-transmission, steep-edge bandpasses, extremely high out-of-band rejection across Si response, sizes accommodating large fields-of-view, precision mechanical filter assemblies and both spectral uniformity and excellent transmitted wavefront across the field. We discuss solutions as satisfied for Spain's state-of-the-art new fast LOCAL UNIVERSE 3° wide-field survey telescope.

  9. Genetic particle filter application to land surface temperature downscaling

    NASA Astrophysics Data System (ADS)

    Mechri, Rihab; Ottlé, Catherine; Pannekoucke, Olivier; Kallel, Abdelaziz

    2014-03-01

    Thermal infrared data are widely used for surface flux estimation giving the possibility to assess water and energy budgets through land surface temperature (LST). Many applications require both high spatial resolution (HSR) and high temporal resolution (HTR), which are not presently available from space. It is therefore necessary to develop methodologies to use the coarse spatial/high temporal resolutions LST remote-sensing products for a better monitoring of fluxes at appropriate scales. For that purpose, a data assimilation method was developed to downscale LST based on particle filtering. The basic tenet of our approach is to constrain LST dynamics simulated at both HSR and HTR, through the optimization of aggregated temperatures at the coarse observation scale. Thus, a genetic particle filter (GPF) data assimilation scheme was implemented and applied to a land surface model which simulates prior subpixel temperatures. First, the GPF downscaling scheme was tested on pseudoobservations generated in the framework of the study area landscape (Crau-Camargue, France) and climate for the year 2006. The GPF performances were evaluated against observation errors and temporal sampling. Results show that GPF outperforms prior model estimations. Finally, the GPF method was applied on Spinning Enhanced Visible and InfraRed Imager time series and evaluated against HSR data provided by an Advanced Spaceborne Thermal Emission and Reflection Radiometer image acquired on 26 July 2006. The temperatures of seven land cover classes present in the study area were estimated with root-mean-square errors less than 2.4 K which is a very promising result for downscaling LST satellite products.

  10. Advanced Filters and Components for Power Applications

    DTIC Science & Technology

    2006-08-31

    Passive Input Filter Design". In Proc. of the 6th National Solid-State Power Conversion Conf., pages G1-1 - G1-10, May 1979. [3] M.J. Nave. Power Line Filter Design for Switched - Mode Power Supplies . Van

  11. Depth Filters Containing Diatomite Achieve More Efficient Particle Retention than Filters Solely Containing Cellulose Fibers

    PubMed Central

    Buyel, Johannes F.; Gruchow, Hannah M.; Fischer, Rainer

    2015-01-01

    The clarification of biological feed stocks during the production of biopharmaceutical proteins is challenging when large quantities of particles must be removed, e.g., when processing crude plant extracts. Single-use depth filters are often preferred for clarification because they are simple to integrate and have a good safety profile. However, the combination of filter layers must be optimized in terms of nominal retention ratings to account for the unique particle size distribution in each feed stock. We have recently shown that predictive models can facilitate filter screening and the selection of appropriate filter layers. Here we expand our previous study by testing several filters with different retention ratings. The filters typically contain diatomite to facilitate the removal of fine particles. However, diatomite can interfere with the recovery of large biopharmaceutical molecules such as virus-like particles and aggregated proteins. Therefore, we also tested filtration devices composed solely of cellulose fibers and cohesive resin. The capacities of both filter types varied from 10 to 50 L m−2 when challenged with tobacco leaf extracts, but the filtrate turbidity was ~500-fold lower (~3.5 NTU) when diatomite filters were used. We also tested pre–coat filtration with dispersed diatomite, which achieved capacities of up to 120 L m−2 with turbidities of ~100 NTU using bulk plant extracts, and in contrast to the other depth filters did not require an upstream bag filter. Single pre-coat filtration devices can thus replace combinations of bag and depth filters to simplify the processing of plant extracts, potentially saving on time, labor and consumables. The protein concentrations of TSP, DsRed and antibody 2G12 were not affected by pre-coat filtration, indicating its general applicability during the manufacture of plant-derived biopharmaceutical proteins. PMID:26734037

  12. Advanced optical interference filters based on metal and dielectric layers.

    PubMed

    Begou, Thomas; Lemarchand, Fabien; Lumeau, Julien

    2016-09-05

    In this paper, we investigate the design and the fabrication of an advanced optical interference filter based on metal and dielectric layers. This filter respects the specifications of the 2016 OIC manufacturing problem contest. We study and present all the challenges and solutions that allowed achieving a low deviation between the fabricated prototype and the target.

  13. COMPUTATIONS ON THE PERFORMANCE OF PARTICLE FILTERS AND ELECTRONIC AIR CLEANERS

    EPA Science Inventory

    The paper discusses computations on the performance of particle filters and electronic air cleaners (EACs). The collection efficiency of particle filters and ACs is calculable if certain factors can be assumed or calibrated. For fibrous particulate filters, measurement of colle...

  14. Fracture behavior of advanced ceramic hot gas filters: Final report

    SciTech Connect

    Singh, J.P.; Majumdar, S.; Sutaria, M.; Bielke, W.

    1997-03-01

    This report presents the results of mechanical/microstructural evaluation, thermal shock/fatigue testing, and stress analyses of advanced hot-gas filters obtained from different manufacturers. These filters were fabricated from both monolithic ceramics and composites. The composite filters, made of both oxide and nonoxide materials, were in both as-fabricated and exposed conditions, whereas the monolithic filters were made only of nonoxide materials. Mechanical property measurement of composite filters included diametral compression testing with O-ring specimens and burst-testing of short filter segments with rubber plugs. In-situ strength of fibers in the composite filters was evaluated by microscopic technique. Thermal shock/fatigue resistance was estimated by measuring the strengths of filter specimens before and after thermal cycling from an air environment at elevated temperatures to a room temperature oil bath. Filter performance during mechanical and thermal shock/fatigue loadings was correlated with microstructural observations. Micromechanical models were developed to derive properties of composite filter constituents on the basis of measured mechanical properties of the filters. Subsequently, these properties were used to analytically predict the performance of composite filters during thermal shock loading.

  15. Effect of particle-fiber friction coefficient on ultrafine aerosol particles clogging in nanofiber based filter

    NASA Astrophysics Data System (ADS)

    Sambaer, Wannes; Zatloukal, Martin; Kimmer, Dusan

    2013-04-01

    Realistic SEM image based 3D filter model considering transition/free molecular flow regime, Brownian diffusion, aerodynamic slip, particle-fiber and particle-particle interactions together with a novel Euclidian distance map based methodology for the pressure drop calculation has been utilized for a polyurethane nanofiber based filter prepared via electrospinning process in order to more deeply understand the effect of particle-fiber friction coefficient on filter clogging and basic filter characteristics. Based on the performed theoretical analysis, it has been revealed that the increase in the fiber-particle friction coefficient causes, firstly, more weaker particle penetration in the filter, creation of dense top layers and generation of higher pressure drop (surface filtration) in comparison with lower particle-fiber friction coefficient filter for which deeper particle penetration takes place (depth filtration), secondly, higher filtration efficiency, thirdly, higher quality factor and finally, higher quality factor sensitivity to the increased collected particle mass. Moreover, it has been revealed that even if the particle-fiber friction coefficient is different, the cake morphology is very similar.

  16. Effects of particle size and velocity on burial depth of airborne particles in glass fiber filters

    SciTech Connect

    Higby, D.P.

    1984-11-01

    Air sampling for particulate radioactive material involves collecting airborne particles on a filter and then determining the amount of radioactivity collected per unit volume of air drawn through the filter. The amount of radioactivity collected is frequently determined by directly measuring the radiation emitted from the particles collected on the filter. Counting losses caused by the particle becoming buried in the filter matrix may cause concentrations of airborne particulate radioactive materials to be underestimated by as much as 50%. Furthermore, the dose calculation for inhaled radionuclides will also be affected. The present study was designed to evaluate the extent to which particle size and sampling velocity influence burial depth in glass-fiber filters. Aerosols of high-fired /sup 239/PuO/sub 2/ were collected at various sampling velocities on glass-fiber filters. The fraction of alpha counts lost due to burial was determined as the ratio of activity detected by direct alpha count to the quantity determined by photon spectrometry. The results show that burial of airborne particles collected on glass-fiber filters appears to be a weak function of sampling velocity and particle size. Counting losses ranged from 0 to 25%. A correction that assumes losses of 10 to 15% would ensure that the concentration of airborne alpha-emitting radionuclides would not be underestimated when glass-fiber filters are used. 32 references, 21 figures, 11 tables.

  17. Segmentation and outline detection in underwater video images using particle filters

    NASA Astrophysics Data System (ADS)

    Yoerger, Edward J.; Charalampidis, Dimitrios; Ioup, George E.; Ioup, Juliette W.

    2016-05-01

    Recently we have been concerned with locating and tracking images of fish in underwater videos. While edge detection and region growing have assisted in obtaining some advances in this effort, a more extensive, non-linear approach appears necessary for improved results. In particular, the use of particle filtering applied to contour detection in natural images has met with some success. Following recent ideas in the literature, we are proposing to use a recursive Bayesian model which employs a sequential Monte Carlo approach, also known as the particle filter. This approach uses the corroboration between two scales of an image to produce various local features which characterize the different probability densities required by the particle filter. Since our data consist of video images of fish recorded by a stationary camera, we are capable of augmenting this process by means of background subtraction. Moreover, we are proposing a method that does not require the pre-computation of the distributions required by the particle filter. The above capabilities are applied to our dataset for the purpose of using contour detection with the aim of eventual segmentation of the fish images and fish classification. Although our dataset consists of fish images, the proposed techniques can be employed in applications involving different kinds of non-stationary underwater objects. We present results and examples of this analysis and discuss the particle filter application to our dataset.

  18. Ultrasonic tracking of shear waves using a particle filter

    PubMed Central

    Ingle, Atul N.; Ma, Chi; Varghese, Tomy

    2015-01-01

    Purpose: This paper discusses an application of particle filtering for estimating shear wave velocity in tissue using ultrasound elastography data. Shear wave velocity estimates are of significant clinical value as they help differentiate stiffer areas from softer areas which is an indicator of potential pathology. Methods: Radio-frequency ultrasound echo signals are used for tracking axial displacements and obtaining the time-to-peak displacement at different lateral locations. These time-to-peak data are usually very noisy and cannot be used directly for computing velocity. In this paper, the denoising problem is tackled using a hidden Markov model with the hidden states being the unknown (noiseless) time-to-peak values. A particle filter is then used for smoothing out the time-to-peak curve to obtain a fit that is optimal in a minimum mean squared error sense. Results: Simulation results from synthetic data and finite element modeling suggest that the particle filter provides lower mean squared reconstruction error with smaller variance as compared to standard filtering methods, while preserving sharp boundary detail. Results from phantom experiments show that the shear wave velocity estimates in the stiff regions of the phantoms were within 20% of those obtained from a commercial ultrasound scanner and agree with estimates obtained using a standard method using least-squares fit. Estimates of area obtained from the particle filtered shear wave velocity maps were within 10% of those obtained from B-mode ultrasound images. Conclusions: The particle filtering approach can be used for producing visually appealing SWV reconstructions by effectively delineating various areas of the phantom with good image quality properties comparable to existing techniques. PMID:26520761

  19. Advanced Techniques for Removal of Retrievable Inferior Vena Cava Filters

    SciTech Connect

    Iliescu, Bogdan; Haskal, Ziv J.

    2012-08-15

    Inferior vena cava (IVC) filters have proven valuable for the prevention of primary or recurrent pulmonary embolism in selected patients with or at high risk for venous thromboembolic disease. Their use has become commonplace, and the numbers implanted increase annually. During the last 3 years, in the United States, the percentage of annually placed optional filters, i.e., filters than can remain as permanent filters or potentially be retrieved, has consistently exceeded that of permanent filters. In parallel, the complications of long- or short-term filtration have become increasingly evident to physicians, regulatory agencies, and the public. Most filter removals are uneventful, with a high degree of success. When routine filter-retrieval techniques prove unsuccessful, progressively more advanced tools and skill sets must be used to enhance filter-retrieval success. These techniques should be used with caution to avoid damage to the filter or cava during IVC retrieval. This review describes the complex techniques for filter retrieval, including use of additional snares, guidewires, angioplasty balloons, and mechanical and thermal approaches as well as illustrates their specific application.

  20. A local particle filter for high-dimensional geophysical systems

    NASA Astrophysics Data System (ADS)

    Penny, Stephen G.; Miyoshi, Takemasa

    2016-11-01

    A local particle filter (LPF) is introduced that outperforms traditional ensemble Kalman filters in highly nonlinear/non-Gaussian scenarios, both in accuracy and computational cost. The standard sampling importance resampling (SIR) particle filter is augmented with an observation-space localization approach, for which an independent analysis is computed locally at each grid point. The deterministic resampling approach of Kitagawa is adapted for application locally and combined with interpolation of the analysis weights to smooth the transition between neighboring points. Gaussian noise is applied with magnitude equal to the local analysis spread to prevent particle degeneracy while maintaining the estimate of the growing dynamical instabilities. The approach is validated against the local ensemble transform Kalman filter (LETKF) using the 40-variable Lorenz-96 (L96) model. The results show that (1) the accuracy of LPF surpasses LETKF as the forecast length increases (thus increasing the degree of nonlinearity), (2) the cost of LPF is significantly lower than LETKF as the ensemble size increases, and (3) LPF prevents filter divergence experienced by LETKF in cases with non-Gaussian observation error distributions.

  1. Nonlinear Statistical Signal Processing: A Particle Filtering Approach

    SciTech Connect

    Candy, J

    2007-09-19

    A introduction to particle filtering is discussed starting with an overview of Bayesian inference from batch to sequential processors. Once the evolving Bayesian paradigm is established, simulation-based methods using sampling theory and Monte Carlo realizations are discussed. Here the usual limitations of nonlinear approximations and non-gaussian processes prevalent in classical nonlinear processing algorithms (e.g. Kalman filters) are no longer a restriction to perform Bayesian inference. It is shown how the underlying hidden or state variables are easily assimilated into this Bayesian construct. Importance sampling methods are then discussed and shown how they can be extended to sequential solutions implemented using Markovian state-space models as a natural evolution. With this in mind, the idea of a particle filter, which is a discrete representation of a probability distribution, is developed and shown how it can be implemented using sequential importance sampling/resampling methods. Finally, an application is briefly discussed comparing the performance of the particle filter designs with classical nonlinear filter implementations.

  2. Advanced lightweight ceramic candle filter module

    SciTech Connect

    Zievers, J.F.; Eggerstedt, P.

    1992-11-01

    To determine the economic effect of light weight ceramics, several sizes of filters were cost estimated for operation at 217.5 psi (15 bar) based on the use of all light weight ceramics (Fibro/Fibro) vs. the use of cooled alloy (RA300) tubesheets and silicon carbide candles (Alloy/SiC). A jet pulse delivery system was included in both estimates. The Fibro/Fibro system was estimated with the plenum design while the Alloy/SiC system was based on header/nozzle design. Battery limits were the filters and jet pulse delivery systems, Ex-works, with no main valves or dust removal systems. It was found that the cost of Fibro/Fibro components were consistently lower than the cost of the Alloy/SiC components; this comparison is illustrated in Figure 8.

  3. Advanced lightweight ceramic candle filter module

    SciTech Connect

    Zievers, J.F.; Eggerstedt, P.

    1992-01-01

    To determine the economic effect of light weight ceramics, several sizes of filters were cost estimated for operation at 217.5 psi (15 bar) based on the use of all light weight ceramics (Fibro/Fibro) vs. the use of cooled alloy (RA300) tubesheets and silicon carbide candles (Alloy/SiC). A jet pulse delivery system was included in both estimates. The Fibro/Fibro system was estimated with the plenum design while the Alloy/SiC system was based on header/nozzle design. Battery limits were the filters and jet pulse delivery systems, Ex-works, with no main valves or dust removal systems. It was found that the cost of Fibro/Fibro components were consistently lower than the cost of the Alloy/SiC components; this comparison is illustrated in Figure 8.

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

    PubMed

    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.

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

    PubMed Central

    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

  6. Localization using omnivision-based manifold particle filters

    NASA Astrophysics Data System (ADS)

    Wong, Adelia; Yousefhussien, Mohammed; Ptucha, Raymond

    2015-01-01

    Developing precise and low-cost spatial localization algorithms is an essential component for autonomous navigation systems. Data collection must be of sufficient detail to distinguish unique locations, yet coarse enough to enable real-time processing. Active proximity sensors such as sonar and rangefinders have been used for interior localization, but sonar sensors are generally coarse and rangefinders are generally expensive. Passive sensors such as video cameras are low cost and feature-rich, but suffer from high dimensions and excessive bandwidth. This paper presents a novel approach to indoor localization using a low cost video camera and spherical mirror. Omnidirectional captured images undergo normalization and unwarping to a canonical representation more suitable for processing. Training images along with indoor maps are fed into a semi-supervised linear extension of graph embedding manifold learning algorithm to learn a low dimensional surface which represents the interior of a building. The manifold surface descriptor is used as a semantic signature for particle filter localization. Test frames are conditioned, mapped to a low dimensional surface, and then localized via an adaptive particle filter algorithm. These particles are temporally filtered for the final localization estimate. The proposed method, termed omnivision-based manifold particle filters, reduces convergence lag and increases overall efficiency.

  7. Model Adaptation for Prognostics in a Particle Filtering Framework

    NASA Technical Reports Server (NTRS)

    Saha, Bhaskar; Goebel, Kai Frank

    2011-01-01

    One of the key motivating factors for using particle filters for prognostics is the ability to include model parameters as part of the state vector to be estimated. This performs model adaptation in conjunction with state tracking, and thus, produces a tuned model that can used for long term predictions. This feature of particle filters works in most part due to the fact that they are not subject to the "curse of dimensionality", i.e. the exponential growth of computational complexity with state dimension. However, in practice, this property holds for "well-designed" particle filters only as dimensionality increases. This paper explores the notion of wellness of design in the context of predicting remaining useful life for individual discharge cycles of Li-ion batteries. Prognostic metrics are used to analyze the tradeoff between different model designs and prediction performance. Results demonstrate how sensitivity analysis may be used to arrive at a well-designed prognostic model that can take advantage of the model adaptation properties of a particle filter.

  8. Recent Advances on Endocrine Disrupting Effects of UV Filters

    PubMed Central

    Wang, Jiaying; Pan, Liumeng; Wu, Shenggan; Lu, Liping; Xu, Yiwen; Zhu, Yanye; Guo, Ming; Zhuang, Shulin

    2016-01-01

    Ultraviolet (UV) filters are used widely in cosmetics, plastics, adhesives and other industrial products to protect human skin or products against direct exposure to deleterious UV radiation. With growing usage and mis-disposition of UV filters, they currently represent a new class of contaminants of emerging concern with increasingly reported adverse effects to humans and other organisms. Exposure to UV filters induce various endocrine disrupting effects, as revealed by increasing number of toxicological studies performed in recent years. It is necessary to compile a systematic review on the current research status on endocrine disrupting effects of UV filters toward different organisms. We therefore summarized the recent advances on the evaluation of the potential endocrine disruptors and the mechanism of toxicity for many kinds of UV filters such as benzophenones, camphor derivatives and cinnamate derivatives. PMID:27527194

  9. Object tracking by co-trained classifiers and particle filters

    NASA Astrophysics Data System (ADS)

    Tang, Liang; Li, Shanqing; Liu, Keyan; Wang, Lei

    2010-01-01

    This paper presents an online object tracking method, in which co-training and particle filters algorithms cooperate and complement each other for robust and effective tracking. Under framework of particle filters, the semi-supervised cotraining algorithm is adopted to construct, on-line update, and mutually boost two complementary object classifiers, which consequently improves discriminant ability of particles and its adaptability to appearance variants caused by illumination changing, pose verying, camera shaking, and occlusion. Meanwhile, to make sampling procedure more efficient, knowledge from coarse confidence maps and spatial-temporal constraints are introduced by importance sampling. It improves not only the accuracy and efficiency of sampling procedure, but also provides more reliable training samples for co-training. Experimental results verify the effectiveness and robustness of our method.

  10. Advances in holographic particle velocimetry

    NASA Astrophysics Data System (ADS)

    Simmons, Scott; Meng, Hui; Hussain, Fazle; Liu, David

    1993-12-01

    Holographic particle velocimetry (HPV) is a promising technique for 3D flow velocity and hence vorticity measurements to study turbulence, coherent structures and vortex interactions. We discuss various aspects in the development of this technique ranging from hologram recording configurations such as in-line, off-axis and multibeam to data processing. Difficulties in implementation are analyzed and solutions are discussed. We also present preliminary measurement results in a 3D vortex flow using one of our prototype HPV systems.

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

    PubMed Central

    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

  12. Utilizing Time Redundancy for Particle Filter-Based Transfer Alignment

    NASA Astrophysics Data System (ADS)

    Chattaraj, Suvendu; Mukherjee, Abhik

    2016-07-01

    Signal detection in the presence of high noise is a challenge in natural sciences. From understanding signals emanating out of deep space probes to signals in protein interactions for systems biology, domain specific innovations are needed. The present work is in the domain of transfer alignment (TA), which deals with estimation of the misalignment of deliverable daughter munitions with respect to that of the delivering mother platform. In this domain, the design of noise filtering scheme has to consider a time varying and nonlinear system dynamics at play. The accuracy of conventional particle filter formulation suffers due to deviations from modeled system dynamics. An evolutionary particle filter can overcome this problem by evolving multiple system models through few support points per particle. However, this variant has even higher time complexity for real-time execution. As a result, measurement update gets deferred and the estimation accuracy is compromised. By running these filter algorithms on multiple processors, the execution time can be reduced, to allow frequent measurement updates. Such scheme ensures better system identification so that performance improves in case of simultaneous ejection of multiple daughters and also results in better convergence of TA algorithms for single daughter.

  13. Ceramem filters for removal of particles from hot gas streams

    SciTech Connect

    Bishop, B.A.; Goldsmith, R.L.

    1994-11-01

    The need for hot gas cleanup in the power, advanced coal conversion, process and incineration industries is well documented and extensive development is being undertaken to develop and demonstrate suitable filtration technologies. In general, process conditions include (a) oxidizing or reducing atmospheres, (b) temperatures to 1800{degree}F, (c) pressures to 300 psi, and (d) potentially corrosive components in the gas stream. The most developed technologies entail the use of candle or tube filters, which suffer from fragility, lack of oxidation/corrosion resistance, and high cost. The ceramic membrane filter described below offers the potential to eliminate these limitations.

  14. A Parameterized Design Framework for Hardware Implementation of Particle Filters

    DTIC Science & Technology

    2008-03-01

    explore differ- ent design options for implementing two different particle filtering applications on field-programmable gate arrays ( FPGAs ), and we present...associated results on trade-offs between area ( FPGA resource requirements) and execution speed. Index Terms — Field programmable gate arrays, Parallel...programmable gate arrays ( FPGAs ) is proposed to enable comprehensive design space exploration of the whole system with attention to the interaction

  15. Chi-squared smoothed adaptive particle-filtering based prognosis

    NASA Astrophysics Data System (ADS)

    Ley, Christopher P.; Orchard, Marcos E.

    2017-01-01

    This paper presents a novel form of selecting the likelihood function of the standard sequential importance sampling/re-sampling particle filter (SIR-PF) with a combination of sliding window smoothing and chi-square statistic weighting, so as to: (a) increase the rate of convergence of a flexible state model with artificial evolution for online parameter learning (b) improve the performance of a particle-filter based prognosis algorithm. This is applied and tested with real data from oil total base number (TBN) measurements from three haul trucks. The oil data has high measurement uncertainty and an unknown phenomenological state model. Performance of the proposed algorithm is benchmarked against the standard form of SIR-PF estimation which utilises the Normal (Gaussian) likelihood function. Both implementations utilise the same particle filter based prognosis algorithm so as to provide a common comparison. A sensitivity analysis is also performed to further explore the effects of the combination of sliding window smoothing and chi-square statistic weighting to the SIR-PF.

  16. Ensemble Data Assimilation for Streamflow Forecasting: Experiments with Ensemble Kalman Filter and Particle Filter

    NASA Astrophysics Data System (ADS)

    Hirpa, F. A.; Gebremichael, M.; Hopson, T. M.; Wojick, R.

    2011-12-01

    We present results of data assimilation of ground discharge observation and remotely sensed soil moisture observations into Sacramento Soil Moisture Accounting (SACSMA) model in a small watershed (1593 km2) in Minnesota, the Unites States. Specifically, we perform assimilation experiments with Ensemble Kalman Filter (EnKF) and Particle Filter (PF) in order to improve streamflow forecast accuracy at six hourly time step. The EnKF updates the soil moisture states in the SACSMA from the relative errors of the model and observations, while the PF adjust the weights of the state ensemble members based on the likelihood of the forecast. Results of the improvements of each filter over the reference model (without data assimilation) will be presented. Finally, the EnKF and PF are coupled together to further improve the streamflow forecast accuracy.

  17. Models of filter-based particle light absorption measurements

    NASA Astrophysics Data System (ADS)

    Hamasha, Khadeejeh M.

    Light absorption by aerosol is very important in the visible, near UN, and near I.R region of the electromagnetic spectrum. Aerosol particles in the atmosphere have a great influence on the flux of solar energy, and also impact health in a negative sense when they are breathed into lungs. Aerosol absorption measurements are usually performed by filter-based methods that are derived from the change in light transmission through a filter where particles have been deposited. These methods suffer from interference between light-absorbing and light-scattering aerosol components. The Aethalometer is the most commonly used filter-based instrument for aerosol light absorption measurement. This dissertation describes new understanding of aerosol light absorption obtained by the filter method. The theory uses a multiple scattering model for the combination of filter and particle optics. The theory is evaluated using Aethalometer data from laboratory and ambient measurements in comparison with photoacoustic measurements of aerosol light absorption. Two models were developed to calculate aerosol light absorption coefficients from the Aethalometer data, and were compared to the in-situ aerosol light absorption coefficients. The first is an approximate model and the second is a "full" model. In the approximate model two extreme cases of aerosol optics were used to develop a model-based calibration scheme for the 7-wavelength Aethalometer. These cases include those of very strong scattering aerosols (Ammonium sulfate sample) and very absorbing aerosols (kerosene soot sample). The exponential behavior of light absorption in the strong multiple scattering limit is shown to be the square root of the total absorption optical depth rather than linear with optical depth as is commonly assumed with Beer's law. 2-stream radiative transfer theory was used to develop the full model to calculate the aerosol light absorption coefficients from the Aethalometer data. This comprehensive model

  18. Point Set Registration via Particle Filtering and Stochastic Dynamics

    PubMed Central

    Sandhu, Romeil; Dambreville, Samuel; Tannenbaum, Allen

    2013-01-01

    In this paper, we propose a particle filtering approach for the problem of registering two point sets that differ by a rigid body transformation. Typically, registration algorithms compute the transformation parameters by maximizing a metric given an estimate of the correspondence between points across the two sets of interest. This can be viewed as a posterior estimation problem, in which the corresponding distribution can naturally be estimated using a particle filter. In this work, we treat motion as a local variation in pose parameters obtained by running a few iterations of a certain local optimizer. Employing this idea, we introduce stochastic motion dynamics to widen the narrow band of convergence often found in local optimizer approaches for registration. Thus, the novelty of our method is threefold: First, we employ a particle filtering scheme to drive the point set registration process. Second, we present a local optimizer that is motivated by the correlation measure. Third, we increase the robustness of the registration performance by introducing a dynamic model of uncertainty for the transformation parameters. In contrast with other techniques, our approach requires no annealing schedule, which results in a reduction in computational complexity (with respect to particle size) as well as maintains the temporal coherency of the state (no loss of information). Also unlike some alternative approaches for point set registration, we make no geometric assumptions on the two data sets. Experimental results are provided that demonstrate the robustness of the algorithm to initialization, noise, missing structures, and/or differing point densities in each set, on several challenging 2D and 3D registration scenarios. PMID:20558877

  19. Independent motion detection with a rival penalized adaptive particle filter

    NASA Astrophysics Data System (ADS)

    Becker, Stefan; Hübner, Wolfgang; Arens, Michael

    2014-10-01

    Aggregation of pixel based motion detection into regions of interest, which include views of single moving objects in a scene is an essential pre-processing step in many vision systems. Motion events of this type provide significant information about the object type or build the basis for action recognition. Further, motion is an essential saliency measure, which is able to effectively support high level image analysis. When applied to static cameras, background subtraction methods achieve good results. On the other hand, motion aggregation on freely moving cameras is still a widely unsolved problem. The image flow, measured on a freely moving camera is the result from two major motion types. First the ego-motion of the camera and second object motion, that is independent from the camera motion. When capturing a scene with a camera these two motion types are adverse blended together. In this paper, we propose an approach to detect multiple moving objects from a mobile monocular camera system in an outdoor environment. The overall processing pipeline consists of a fast ego-motion compensation algorithm in the preprocessing stage. Real-time performance is achieved by using a sparse optical flow algorithm as an initial processing stage and a densely applied probabilistic filter in the post-processing stage. Thereby, we follow the idea proposed by Jung and Sukhatme. Normalized intensity differences originating from a sequence of ego-motion compensated difference images represent the probability of moving objects. Noise and registration artefacts are filtered out, using a Bayesian formulation. The resulting a posteriori distribution is located on image regions, showing strong amplitudes in the difference image which are in accordance with the motion prediction. In order to effectively estimate the a posteriori distribution, a particle filter is used. In addition to the fast ego-motion compensation, the main contribution of this paper is the design of the probabilistic

  20. Particle filtering for dispersion curve tracking in ocean acoustics.

    PubMed

    Zorych, Ivan; Michalopoulou, Zoi-Heleni

    2008-08-01

    A particle filtering method is developed for dispersion curve extraction from spectrograms of broadband acoustic signals propagating in underwater media. The goal is to obtain accurate representation of modal dispersion which can be employed for source localization and geoacoustic inversion. Results are presented from the application of the method to synthetic data, demonstrating the potential of the approach for accurate estimation of waveguide dispersion characteristics. The method outperforms simple time-frequency analysis providing estimates that are very close to numerically calculated dispersion curves. The method also provides uncertainty information on modal arrival time estimates, typically unavailable when traditional methods are used.

  1. Symmetric Phase-Only Filtering in Particle-Image Velocimetry

    NASA Technical Reports Server (NTRS)

    Wemet, Mark P.

    2008-01-01

    Symmetrical phase-only filtering (SPOF) can be exploited to obtain substantial improvements in the results of data processing in particle-image velocimetry (PIV). In comparison with traditional PIV data processing, SPOF PIV data processing yields narrower and larger amplitude correlation peaks, thereby providing more-accurate velocity estimates. The higher signal-to-noise ratios associated with the higher amplitude correlation peaks afford greater robustness and reliability of processing. SPOF also affords superior performance in the presence of surface flare light and/or background light. SPOF algorithms can readily be incorporated into pre-existing algorithms used to process digitized image data in PIV, without significantly increasing processing times. A summary of PIV and traditional PIV data processing is prerequisite to a meaningful description of SPOF PIV processing. In PIV, a pulsed laser is used to illuminate a substantially planar region of a flowing fluid in which particles are entrained. An electronic camera records digital images of the particles at two instants of time. The components of velocity of the fluid in the illuminated plane can be obtained by determining the displacements of particles between the two illumination pulses. The objective in PIV data processing is to compute the particle displacements from the digital image data. In traditional PIV data processing, to which the present innovation applies, the two images are divided into a grid of subregions and the displacements determined from cross-correlations between the corresponding sub-regions in the first and second images. The cross-correlation process begins with the calculation of the Fourier transforms (or fast Fourier transforms) of the subregion portions of the images. The Fourier transforms from the corresponding subregions are multiplied, and this product is inverse Fourier transformed, yielding the cross-correlation intensity distribution. The average displacement of the

  2. Particle filter based on thermophoretic deposition from natural convection flow

    SciTech Connect

    Sasse, A.G.B.M.; Nazaroff, W.W. ); Gadgil, A.J. )

    1994-04-01

    We present an analysis of particle migration in a natural convection flow between parallel plates and within the annulus of concentric tubes. The flow channel is vertically oriented with one surface maintained at a higher temperature than the other. Particle migration is dominated by advection in the vertical direction and thermophoresis in the horizontal direction. From scale analysis it is demonstrated that particles are completely removed from air flowing through the channel if its length exceeds L[sub c] = (b[sup 4]g/24K[nu][sup 2]), where b is the width of the channel, g is the acceleration of gravity, K is a thermophoretic coefficient of order 0.5, and [nu] is the kinematic viscosity of air. Precise predictions of particle removal efficiency as a function of system parameters are obtained by numerical solution of the governing equations. Based on the model results, it appears feasible to develop a practical filter for removing smoke particles from a smoldering cigarette in an ashtray by using natural convection in combination with thermophoresis. 22 refs., 8 figs., 1 tab.

  3. Comparative evaluation of ensemble Kalman filter, particle filter and variational techniques for river discharge forecast

    NASA Astrophysics Data System (ADS)

    Hirpa, F. A.; Gebremichael, M.; LEE, H.; Hopson, T. M.

    2012-12-01

    Hydrologic data assimilation techniques provide a means to improve river discharge forecasts through updating hydrologic model states and correcting the atmospheric forcing data via optimally combining model outputs with observations. The performance of the assimilation procedure, however, depends on the data assimilation techniques used and the amount of uncertainty in the data sets. To investigate the effects of these, we comparatively evaluate three data assimilation techniques, including ensemble Kalman filter (EnKF), particle filter (PF) and variational (VAR) technique, which assimilate discharge and synthetic soil moisture data at various uncertainty levels into the Sacramento Soil Moisture accounting (SAC-SMA) model used by the National Weather Service (NWS) for river forecasting in The United States. The study basin is Greens Bayou watershed with area of 178 km2 in eastern Texas. In the presentation, we summarize the results of the comparisons, and discuss the challenges of applying each technique for hydrologic applications.

  4. ECG Denoising Using Marginalized Particle Extended Kalman Filter with an Automatic Particle Weighting Strategy.

    PubMed

    Hesar, Hamed; Mohebbi, Maryam

    2016-06-20

    In this paper a model-based Bayesian filtering framework called the "marginalized particle-extended Kalman filter (MP-EKF) algorithm" is proposed for electrocardiogram (ECG) denoising. This algorithm does not have the extended Kalman filter (EKF) shortcoming in handling non-Gaussian nonstationary situations because of its nonlinear framework. In addition, it has less computational complexity compared with particle filter. This filter improves ECG denoising performance by implementing marginalized particle filter framework while reducing its computational complexity using EKF framework. An automatic particle weighting strategy is also proposed here that controls the reliance of our framework to the acquired measurements. We evaluated the proposed filter on several normal ECGs selected from MIT-BIH normal sinus rhythm database. To do so, artificial white Gaussian and colored noises as well as nonstationary real muscle artifact (MA) noise over a range of low SNRs from 10 to -5 dB were added to these normal ECG segments. The benchmark methods were the EKF and extended Kalman smoother (EKS) algorithms which are the first model-based Bayesian algorithms introduced in the field of ECG denoising. From SNR viewpoint, the experiments showed that in the presence of Gaussian white noise, the proposed framework outperforms the EKF and EKS algorithms in lower input SNRs where the measurements and state model are not reliable. Owing to its nonlinear framework and particle weighting strategy, the proposed algorithm attained better results at all input SNRs in non-Gaussian non-stationary situations (such as presence of pink noise, brown noise, and real muscle artifacts). In addition, the impact of the proposed filtering method on the distortion of diagnostic features of the ECG was investigated and compared with EKF/EKS methods using an ECG diagnostic distortion measure called the "Multi-Scale Entropy Based Weighted Distortion Measure" or MSEWPRD. The results revealed that our

  5. Loss of fine particle ammonium from denuded nylon filters

    NASA Astrophysics Data System (ADS)

    Yu, Xiao-Ying; Lee, Taehyoung; Ayres, Benjamin; Kreidenweis, Sonia M.; Malm, William; Collett, Jeffrey L.

    Ammonium is an important constituent of fine particulate mass in the atmosphere, but can be difficult to quantify due to possible sampling artifacts. Losses of semivolatile species such as NH 4NO 3 can be particularly problematic. In order to evaluate ammonium losses from aerosol particles collected on filters, a series of field experiments was conducted using denuded nylon and Teflon filters at Bondville, IL (February 2003), San Gorgonio, CA (April 2003 and July 2004), Grand Canyon NP, AZ (May, 2003), Brigantine, NJ (November 2003), and Great Smoky Mountains National Park (NP), TN (July-August 2004). Samples were collected over 24 h periods. Losses from denuded nylon filters ranged from 10% (monthly average) in Bondville, IL to 28% in San Gorgonio, CA in summer. Losses on individual sample days ranged from 1% to 65%. Losses tended to increase with increasing diurnal temperature and relative humidity changes and with the fraction of ambient total N(-III) (particulate NH 4++gaseous NH 3) present as gaseous NH 3. The amount of ammonium lost at most sites could be explained by the amount of NH 4NO 3 present in the sampled aerosol. Ammonium losses at Great Smoky Mountains NP, however, significantly exceeded the amount of NH 4NO 3 collected. Ammoniated organic salts are suggested as additional important contributors to observed ammonium loss at this location.

  6. Loss of Fine Particle Ammonium from Denuded Nylon Filters

    SciTech Connect

    Yu, Xiao-Ying; Lee, Taehyoung; Ayres, Benjamin; Kreidenweis, Sonia M.; Malm, William C.; Collett, Jeffrey L.

    2006-08-01

    Ammonium is an important constituent of fine particulate mass in the atmosphere, but can be difficult to quantify due to possible sampling artifacts. Losses of semivolatile species such as NH4NO3 can be particularly problematic. In order to evaluate ammonium losses from aerosol particles collected on filters, a series of field experiments was conducted using denuded nylon and Teflon filters at Bondville, Illinois (February 2003), San Gorgonio, California (April 2003 and July 2004), Grand Canyon National Park, Arizona (May, 2003), Brigantine, New Jersey (November 2003), and Great Smoky Mountains National Park (NP), Tennessee (July–August 2004). Samples were collected over 24-hr periods. Losses from denuded nylon filters ranged from 10% (monthly average) in Bondville, Illinois to 28% in San Gorgonio, California in summer. Losses on individual sample days ranged from 1% to 65%. Losses tended to increase with increasing diurnal temperature and relative humidity changes and with the fraction of ambient total N(--III) (particulate NH4+ plus gaseous NH3) present as gaseous NH3. The amount of ammonium lost at most sites could be explained by the amount of NH4NO3 present in the sampled aerosol. Ammonium losses at Great Smoky Mountains NP, however, significantly exceeded the amount of NH4NO3 collected. Ammoniated organic salts are suggested as additional important contributors to observed ammonium loss at this location.

  7. Lagrangian filtered density function for LES-based stochastic modelling of turbulent particle-laden flows

    NASA Astrophysics Data System (ADS)

    Innocenti, Alessio; Marchioli, Cristian; Chibbaro, Sergio

    2016-11-01

    The Eulerian-Lagrangian approach based on Large-Eddy Simulation (LES) is one of the most promising and viable numerical tools to study particle-laden turbulent flows, when the computational cost of Direct Numerical Simulation (DNS) becomes too expensive. The applicability of this approach is however limited if the effects of the Sub-Grid Scales (SGSs) of the flow on particle dynamics are neglected. In this paper, we propose to take these effects into account by means of a Lagrangian stochastic SGS model for the equations of particle motion. The model extends to particle-laden flows the velocity-filtered density function method originally developed for reactive flows. The underlying filtered density function is simulated through a Lagrangian Monte Carlo procedure that solves a set of Stochastic Differential Equations (SDEs) along individual particle trajectories. The resulting model is tested for the reference case of turbulent channel flow, using a hybrid algorithm in which the fluid velocity field is provided by LES and then used to advance the SDEs in time. The model consistency is assessed in the limit of particles with zero inertia, when "duplicate fields" are available from both the Eulerian LES and the Lagrangian tracking. Tests with inertial particles were performed to examine the capability of the model to capture the particle preferential concentration and near-wall segregation. Upon comparison with DNS-based statistics, our results show improved accuracy and considerably reduced errors with respect to the case in which no SGS model is used in the equations of particle motion.

  8. Speech enhancement based on nonlinear models using particle filters.

    PubMed

    Mustière, Frédéric; Bolić, Miodrag; Bouchard, Martin

    2009-12-01

    Motivated by the reportedly strong performance of particle filters (PFs) for noise reduction on essentially linear speech production models, and the mounting evidence that the introduction of nonlinearities can lead to a refined speech model, this paper presents a study of PF solutions to the problem of speech enhancement in the context of nonlinear, neural-type speech models. Several variations of a global model are presented (single/multiple neurons; bias/no bias), and corresponding PF solutions are derived. Different importance functions are given when beneficial, Rao-Blackwellization is proposed when possible, and dual/nondual versions of each algorithms are presented. The method shown can handle both white and colored noise. Using a variety of speech and noise signals and different objective quality measures, the performance of these algorithms are evaluated against other PF solutions running on linear models, as well as some traditional enhancement algorithms. A certain hierarchy in performance is established between each algorithm in the paper. Depending on the experimental conditions, the best-performing algorithms are a classical Rao-Blackwellized particle filter (RBPF) running on a linear model, and a proposed PF employing a nondual, nonlinear model with multiple neurons and no biases. With consistence, the neural-network-based PF outperforms RBPF at low signal-to-noise ratio (SNR).

  9. Proposed hardware architectures of particle filter for object tracking

    NASA Astrophysics Data System (ADS)

    Abd El-Halym, Howida A.; Mahmoud, Imbaby Ismail; Habib, SED

    2012-12-01

    In this article, efficient hardware architectures for particle filter (PF) are presented. We propose three different architectures for Sequential Importance Resampling Filter (SIRF) implementation. The first architecture is a two-step sequential PF machine, where particle sampling, weight, and output calculations are carried out in parallel during the first step followed by sequential resampling in the second step. For the weight computation step, a piecewise linear function is used instead of the classical exponential function. This decreases the complexity of the architecture without degrading the results. The second architecture speeds up the resampling step via a parallel, rather than a serial, architecture. This second architecture targets a balance between hardware resources and the speed of operation. The third architecture implements the SIRF as a distributed PF composed of several processing elements and central unit. All the proposed architectures are captured using VHDL synthesized using Xilinx environment, and verified using the ModelSim simulator. Synthesis results confirmed the resource reduction and speed up advantages of our architectures.

  10. Advanced analysis methods in particle physics

    SciTech Connect

    Bhat, Pushpalatha C.; /Fermilab

    2010-10-01

    Each generation of high energy physics experiments is grander in scale than the previous - more powerful, more complex and more demanding in terms of data handling and analysis. The spectacular performance of the Tevatron and the beginning of operations of the Large Hadron Collider, have placed us at the threshold of a new era in particle physics. The discovery of the Higgs boson or another agent of electroweak symmetry breaking and evidence of new physics may be just around the corner. The greatest challenge in these pursuits is to extract the extremely rare signals, if any, from huge backgrounds arising from known physics processes. The use of advanced analysis techniques is crucial in achieving this goal. In this review, I discuss the concepts of optimal analysis, some important advanced analysis methods and a few examples. The judicious use of these advanced methods should enable new discoveries and produce results with better precision, robustness and clarity.

  11. Optimizing Parameters of Process-Based Terrestrial Ecosystem Model with Particle Filter

    NASA Astrophysics Data System (ADS)

    Ito, A.

    2014-12-01

    Present terrestrial ecosystem models still contain substantial uncertainties, as model intercomparison studies have shown, because of poor model constraint by observational data. So, development of advanced methodology of data-model fusion, or data-assimilation, is an important task to reduce the uncertainties and improve model predictability. In this study, I apply the Particle filter (or Sequential Monte Carlo filer) to optimize parameters of a process-based terrestrial ecosystem model (VISIT). The Particle filter is one of the data-assimilation methods, in which probability distribution of model state is approximated by many samples of parameter set (i.e., particle). This is a computationally intensive method and applicable to nonlinear systems; this is an advantage of the method in comparison with other techniques like Ensemble Kalman filter and variational method. At several sites, I used flux measurement data of atmosphere-ecosystem CO2 exchange in sequential and non-sequential manners. In the sequential data assimilation, a time-series data at 30-min or daily steps were used to optimize gas-exchange-related parameters; this method would be also effective to assimilate satellite observational data. On the other hand, in the non-sequential case, annual or long-term mean budget was adjusted to observations; this method would be also effective to assimilate carbon stock data. Although there remain technical issues (e.g., appropriate number of particles and likelihood function), I demonstrate that the Partile filter is an effective method of data-assimilation for process-based models, enhancing collaboration between field and model researchers.

  12. A HIGH TEMPERATURE TEST FACILITY FOR STUDYING ASH PARTICLE CHARACTERISTICS OF CANDLE FILTER DURING SURFACE REGENERATION

    SciTech Connect

    Kang, B.S-J.; Johnson, E.K.; Rincon, J.

    2002-09-19

    Hot gas particulate filtration is a basic component in advanced power generation systems such as Integrated Gasification Combined Cycle (IGCC) and Pressurized Fluidized Bed Combustion (PFBC). These systems require effective particulate removal to protect the downstream gas turbine and also to meet environmental emission requirements. The ceramic barrier filter is one of the options for hot gas filtration. Hot gases flow through ceramic candle filters leaving ash deposited on the outer surface of the filter. A process known as surface regeneration removes the deposited ash periodically by using a high pressure back pulse cleaning jet. After this cleaning process has been done there may be some residual ash on the filter surface. This residual ash may grow and this may lead to mechanical failure of the filter. A High Temperature Test Facility (HTTF) was built to investigate the ash characteristics during surface regeneration at high temperatures. The system is capable of conducting surface regeneration tests of a single candle filter at temperatures up to 1500 F. Details of the HTTF apparatus as well as some preliminary test results are presented in this paper. In order to obtain sequential digital images of ash particle distribution during the surface regeneration process, a high resolution, high speed image acquisition system was integrated into the HTTF system. The regeneration pressure and the transient pressure difference between the inside of the candle filter and the chamber during regeneration were measured using a high speed PC data acquisition system. The control variables for the high temperature regeneration tests were (1) face velocity, (2) pressure of the back pulse, and (3) cyclic ash built-up time.

  13. Hollywood log-homotopy: movies of particle flow for nonlinear filters

    NASA Astrophysics Data System (ADS)

    Daum, Fred; Huang, Jim

    2011-06-01

    In this paper we show five movies of particle flow to provide insight and intuition about this new algorithm. The particles flow solves the well known and important problem of particle degeneracy. Bayes' rule is implemented by particle flow rather than as a pointwise multiplication. This theory is roughly seven orders of magnitude faster than standard particle filters, and it often beats the extended Kalman filter by two orders of magnitude in accuracy for difficult nonlinear problems.

  14. The filter-loading effect by ambient aerosols in filter absorption photometers depends on the coating of the sampled particles

    NASA Astrophysics Data System (ADS)

    Drinovec, Luka; Gregorič, Asta; Zotter, Peter; Wolf, Robert; Bruns, Emily Anne; Prévôt, André S. H.; Petit, Jean-Eudes; Favez, Olivier; Sciare, Jean; Arnold, Ian J.; Chakrabarty, Rajan K.; Moosmüller, Hans; Filep, Agnes; Močnik, Griša

    2017-03-01

    Black carbon is a primary aerosol tracer for high-temperature combustion emissions and can be used to characterize the time evolution of its sources. It is correlated with a decrease in public health and contributes to atmospheric warming. Black carbon measurements are usually conducted with absorption filter photometers, which are prone to several artifacts, including the filter-loading effect - a saturation of the instrumental response due to the accumulation of the sample in the filter matrix. In this paper, we investigate the hypothesis that this filter-loading effect depends on the optical properties of particles present in the filter matrix, especially on the black carbon particle coating. We conducted field campaigns in contrasting environments to determine the influence of source characteristics, particle age and coating on the magnitude of the filter-loading effect. High-time-resolution measurements of the filter-loading parameter in filter absorption photometers show daily and seasonal variations of the effect. The variation is most pronounced in the near-infrared region, where the black carbon mass concentration is determined. During winter, the filter-loading parameter value increases with the absorption Ångström exponent. It is suggested that this effect is related to the size of the black carbon particle core as the wood burning (with higher values of the absorption Ångström exponent) produces soot particles with larger diameters. A reduction of the filter-loading effect is correlated with the availability of the coating material. As the coating of ambient aerosols is reduced or removed, the filter-loading parameter increases. Coatings composed of ammonium sulfate and secondary organics seem to be responsible for the variation of the loading effect. The potential source contribution function analysis shows that high values of the filter-loading parameter in the infrared are indicative of local pollution, whereas low values of the filter

  15. A MultiScale Particle Filter Framework for Contour Detection.

    PubMed

    Widynski, Nicolas; Mignotte, Max

    2014-10-01

    We investigate the contour detection task in complex natural images. We propose a novel contour detection algorithm which jointly tracks at two scales small pieces of edges called edgelets. This multiscale edgelet structure naturally embeds semi-local information and is the basic element of the proposed recursive Bayesian modeling. Prior and transition distributions are learned offline using a shape database. Likelihood functions are learned online, thus are adaptive to an image, and integrate color and gradient information via local, textural, oriented, and profile gradient-based features. The underlying model is estimated using a sequential Monte Carlo approach, and the final soft contour detection map is retrieved from the approximated trajectory distribution. We also propose to extend the model to the interactive cut-out task. Experiments conducted on the Berkeley Segmentation data sets show that the proposed MultiScale Particle Filter Contour Detector method performs well compared to competing state-of-the-art methods.

  16. Geoacoustic and source tracking using particle filtering: experimental results.

    PubMed

    Yardim, Caglar; Gerstoft, Peter; Hodgkiss, William S

    2010-07-01

    A particle filtering (PF) approach is presented for performing sequential geoacoustic inversion of a complex ocean acoustic environment using a moving acoustic source. This approach treats both the environmental parameters [e.g., water column sound speed profile (SSP), water depth, sediment and bottom parameters] at the source location and the source parameters (e.g., source depth, range and speed) as unknown random variables that evolve as the source moves. This allows real-time updating of the environment and accurate tracking of the moving source. As a sequential Monte Carlo technique that operates on nonlinear systems with non-Gaussian probability densities, the PF is an ideal algorithm to perform tracking of environmental and source parameters, and their uncertainties via the evolving posterior probability densities. The approach is demonstrated on both simulated data in a shallow water environment with a sloping bottom and experimental data collected during the SWellEx-96 experiment.

  17. Modular particle filtering FPGA hardware architecture for brain machine interfaces.

    PubMed

    Mountney, John; Obeid, Iyad; Silage, Dennis

    2011-01-01

    As the computational complexities of neural decoding algorithms for brain machine interfaces (BMI) increase, their implementation through sequential processors becomes prohibitive for real-time applications. This work presents the field programmable gate array (FPGA) as an alternative to sequential processors for BMIs. The reprogrammable hardware architecture of the FPGA provides a near optimal platform for performing parallel computations in real-time. The scalability and reconfigurability of the FPGA accommodates diverse sets of neural ensembles and a variety of decoding algorithms. Throughput is significantly increased by decomposing computations into independent parallel hardware modules on the FPGA. This increase in throughput is demonstrated through a parallel hardware implementation of the auxiliary particle filtering signal processing algorithm.

  18. International Space Station (ISS) Advanced Recycle Filter Tank Assembly (ARFTA)

    NASA Technical Reports Server (NTRS)

    Nasrullah, Mohammed K.

    2013-01-01

    The International Space Station (ISS) Recycle Filter Tank Assembly (RFTA) provides the following three primary functions for the Urine Processor Assembly (UPA): volume for concentrating/filtering pretreated urine, filtration of product distillate, and filtration of the Pressure Control and Pump Assembly (PCPA) effluent. The RFTAs, under nominal operations, are to be replaced every 30 days. This poses a significant logistical resupply problem, as well as cost in upmass and new tanks purchase. In addition, it requires significant amount of crew time. To address and resolve these challenges, NASA required Boeing to develop a design which eliminated the logistics and upmass issues and minimize recurring costs. Boeing developed the Advanced Recycle Filter Tank Assembly (ARFTA) that allowed the tanks to be emptied on-orbit into disposable tanks that eliminated the need for bringing the fully loaded tanks to earth for refurbishment and relaunch, thereby eliminating several hundred pounds of upmass and its associated costs. The ARFTA will replace the RFTA by providing the same functionality, but with reduced resupply requirements

  19. Motion-compensated speckle tracking via particle filtering

    NASA Astrophysics Data System (ADS)

    Liu, Lixin; Yagi, Shin-ichi; Bian, Hongyu

    2015-07-01

    Recently, an improved motion compensation method that uses the sum of absolute differences (SAD) has been applied to frame persistence utilized in conventional ultrasonic imaging because of its high accuracy and relative simplicity in implementation. However, high time consumption is still a significant drawback of this space-domain method. To seek for a more accelerated motion compensation method and verify if it is possible to eliminate conventional traversal correlation, motion-compensated speckle tracking between two temporally adjacent B-mode frames based on particle filtering is discussed. The optimal initial density of particles, the least number of iterations, and the optimal transition radius of the second iteration are analyzed from simulation results for the sake of evaluating the proposed method quantitatively. The speckle tracking results obtained using the optimized parameters indicate that the proposed method is capable of tracking the micromotion of speckle throughout the region of interest (ROI) that is superposed with global motion. The computational cost of the proposed method is reduced by 25% compared with that of the previous algorithm and further improvement is necessary.

  20. Joint tracking algorithm using particle filter and mean shift with target model updating

    NASA Astrophysics Data System (ADS)

    Zhang, Bo; Tian, Weifeng; Jin, Zhihua

    2006-10-01

    Roughly, visual tracking algorithms can be divided into two main classes: deterministic tracking and stochastic tracking. Mean shift and particle filter are their typical representatives, respectively. Recently, a hybrid tracker, seamlessly integrating the respective advantages of mean shift and particle filter (MSPF) has achieved impressive success in robust tracking. The pivot of MSPF is to sample fewer particles using particle filter and then those particles are shifted to their respective local maximum of target searching space by mean shift. MSPF not only can greatly reduce the number of particles that particle filter required, but can remedy the deficiency of mean shift. Unfortunately, due to its inherent principle, MSPF is restricted to those applications with little changes of the target model. To make MSPF more flexible and robust, an adaptive target model is extended to MSPF in this paper. Experimental results show that MSPF with target model updating can robustly track the target through the whole sequences regardless of the change of target model.

  1. Particle filtering based structural assessment with acoustic emission sensing

    NASA Astrophysics Data System (ADS)

    Yan, Wuzhao; Abdelrahman, Marwa; Zhang, Bin; Ziehl, Paul

    2017-02-01

    Nuclear structures are designed to withstand severe loading events under various stresses. Over time, aging of structural systems constructed with concrete and steel will occur. This deterioration may reduce service life of nuclear facilities and/or lead to unnecessary or untimely repairs. Therefore, online monitoring of structures in nuclear power plants and waste storage has drawn significant attention in recent years. Of many existing non-destructive evaluation and structural monitoring approaches, acoustic emission is promising for assessment of structural damage because it is non-intrusive and is sensitive to corrosion and crack growth in reinforced concrete elements. To provide a rapid, actionable, and graphical means for interpretation Intensity Analysis plots have been developed. This approach provides a means for classification of damage. Since the acoustic emission measurement is only an indirect indicator of structural damage, potentially corrupted by non-genuine data, it is more suitable to estimate the states of corrosion and cracking in a Bayesian estimation framework. In this paper, we will utilize the accelerated corrosion data from a specimen at the University of South Carolina to develop a particle filtering-based diagnosis and prognosis algorithm. Promising features of the proposed algorithm are described in terms of corrosion state estimation and prediction of degradation over time to a predefined threshold.

  2. Sequential bearings-only-tracking initiation with particle filtering method.

    PubMed

    Liu, Bin; Hao, Chengpeng

    2013-01-01

    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.

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

    PubMed Central

    Hao, Chengpeng

    2013-01-01

    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. PMID:24453865

  4. Ultrafine particle removal by residential heating, ventilating, and air-conditioning filters.

    PubMed

    Stephens, B; Siegel, J A

    2013-12-01

    This work uses an in situ filter test method to measure the size-resolved removal efficiency of indoor-generated ultrafine particles (approximately 7-100 nm) for six new commercially available filters installed in a recirculating heating, ventilating, and air-conditioning (HVAC) system in an unoccupied test house. The fibrous HVAC filters were previously rated by the manufacturers according to ASHRAE Standard 52.2 and ranged from shallow (2.5 cm) fiberglass panel filters (MERV 4) to deep-bed (12.7 cm) electrostatically charged synthetic media filters (MERV 16). Measured removal efficiency ranged from 0 to 10% for most ultrafine particles (UFP) sizes with the lowest rated filters (MERV 4 and 6) to 60-80% for most UFP sizes with the highest rated filter (MERV 16). The deeper bed filters generally achieved higher removal efficiencies than the panel filters, while maintaining a low pressure drop and higher airflow rate in the operating HVAC system. Assuming constant efficiency, a modeling effort using these measured values for new filters and other inputs from real buildings shows that MERV 13-16 filters could reduce the indoor proportion of outdoor UFPs (in the absence of indoor sources) by as much as a factor of 2-3 in a typical single-family residence relative to the lowest efficiency filters, depending in part on particle size.

  5. Continuous and Discrete Space Particle Filters for Predictions in Acoustic Positioning

    NASA Astrophysics Data System (ADS)

    Bauer, Will; Kim, Surrey; Kouritzin, Michael A.

    2002-12-01

    Predicting the future state of a random dynamic signal based on corrupted, distorted, and partial observations is vital for proper real-time control of a system that includes time delay. Motivated by problems from Acoustic Positioning Research Inc., we consider the continual automated illumination of an object moving within a bounded domain, which requires object location prediction due to inherent mechanical and physical time lags associated with robotic lighting. Quality computational predictions demand high fidelity models for the coupled moving object signal and observation equipment pair. In our current problem, the signal represents the vector position, orientation, and velocity of a stage performer. Acoustic observations are formed by timing ultrasonic waves traveling from four perimeter speakers to a microphone attached to the performer. The goal is to schedule lighting movements that are coordinated with the performer by anticipating his/her future position based upon these observations using filtering theory. Particle system based methods have experienced rapid development and have become an essential technique of contemporary filtering strategies. Hitherto, researchers have largely focused on continuous state particle filters, ranging from traditional weighted particle filters to adaptive refining particle filters, readily able to perform path-space estimation and prediction. Herein, we compare the performance of a state-of-the-art refining particle filter to that of a novel discrete-space particle filter on the acoustic positioning problem. By discrete space particle filter we mean a Markov chain that counts particles in discretized cells of the signal state space in order to form an approximated unnormalized distribution of the signal state. For both filters mentioned above, we will examine issues like the mean time to localize a signal, the fidelity of filter estimates at various signal to noise ratios, computational costs, and the effect of signal

  6. Improving Hydrologic Data Assimilation by a Multivariate Particle Filter-Markov Chain Monte Carlo

    NASA Astrophysics Data System (ADS)

    Yan, H.; DeChant, C. M.; Moradkhani, H.

    2014-12-01

    Data assimilation (DA) is a popular method for merging information from multiple sources (i.e. models and remotely sensing), leading to improved hydrologic prediction. With the increasing availability of satellite observations (such as soil moisture) in recent years, DA is emerging in operational forecast systems. Although these techniques have seen widespread application, developmental research has continued to further refine their effectiveness. This presentation will examine potential improvements to the Particle Filter (PF) through the inclusion of multivariate correlation structures. Applications of the PF typically rely on univariate DA schemes (such as assimilating the outlet observed discharge), and multivariate schemes generally ignore the spatial correlation of the observations. In this study, a multivariate DA scheme is proposed by introducing geostatistics into the newly developed particle filter with Markov chain Monte Carlo (PF-MCMC) method. This new method is assessed by a case study over one of the basin with natural hydrologic process in Model Parameter Estimation Experiment (MOPEX), located in Arizona. The multivariate PF-MCMC method is used to assimilate the Advanced Scatterometer (ASCAT) grid (12.5 km) soil moisture retrievals and the observed streamflow in five gages (four inlet and one outlet gages) into the Sacramento Soil Moisture Accounting (SAC-SMA) model for the same scale (12.5 km), leading to greater skill in hydrologic predictions.

  7. Evaporation of suspensions to form an incompressible cake and to fill filter pores with solid particles

    NASA Astrophysics Data System (ADS)

    Khuzhayorov, B. Kh.

    2011-11-01

    Equations of filtration of suspensions to form an incompressible cake of particles on the surface of the filter with simultaneous passage of a certain share of the particles from the cake to the filter's pore space and next to the region of a filtered liquid are derived from the principles of the mechanics of multiphase media. The influence of the travel of the particles in the region of the cake and the filter on the dynamics of growth of the cake bed is investigated. An analysis of the derived dynamic filtration equations shows that allowance for the factors of travel and accumulation of particles in the cake and the filter causes their total filtration resistance, in particular the resistance in the inertial component of the filtration law, to decrease.

  8. Particle filtering with path sampling and an application to a bimodal ocean current model

    SciTech Connect

    Weare, Jonathan

    2009-07-01

    This paper introduces a recursive particle filtering algorithm designed to filter high dimensional systems with complicated non-linear and non-Gaussian effects. The method incorporates a parallel marginalization (PMMC) step in conjunction with the hybrid Monte Carlo (HMC) scheme to improve samples generated by standard particle filters. Parallel marginalization is an efficient Markov chain Monte Carlo (MCMC) strategy that uses lower dimensional approximate marginal distributions of the target distribution to accelerate equilibration. As a validation the algorithm is tested on a 2516 dimensional, bimodal, stochastic model motivated by the Kuroshio current that runs along the Japanese coast. The results of this test indicate that the method is an attractive alternative for problems that require the generality of a particle filter but have been inaccessible due to the limitations of standard particle filtering strategies.

  9. ASME AG-1 Section FC Qualified HEPA Filters; a Particle Loading Comparison - 13435

    SciTech Connect

    Stillo, Andrew; Ricketts, Craig I.

    2013-07-01

    High Efficiency Particulate Air (HEPA) Filters used to protect personnel, the public and the environment from airborne radioactive materials are designed, manufactured and qualified in accordance with ASME AG-1 Code section FC (HEPA Filters) [1]. The qualification process requires that filters manufactured in accordance with this ASME AG-1 code section must meet several performance requirements. These requirements include performance specifications for resistance to airflow, aerosol penetration, resistance to rough handling, resistance to pressure (includes high humidity and water droplet exposure), resistance to heated air, spot flame resistance and a visual/dimensional inspection. None of these requirements evaluate the particle loading capacity of a HEPA filter design. Concerns, over the particle loading capacity, of the different designs included within the ASME AG-1 section FC code[1], have been voiced in the recent past. Additionally, the ability of a filter to maintain its integrity, if subjected to severe operating conditions such as elevated relative humidity, fog conditions or elevated temperature, after loading in use over long service intervals is also a major concern. Although currently qualified HEPA filter media are likely to have similar loading characteristics when evaluated independently, filter pleat geometry can have a significant impact on the in-situ particle loading capacity of filter packs. Aerosol particle characteristics, such as size and composition, may also have a significant impact on filter loading capacity. Test results comparing filter loading capacities for three different aerosol particles and three different filter pack configurations are reviewed. The information presented represents an empirical performance comparison among the filter designs tested. The results may serve as a basis for further discussion toward the possible development of a particle loading test to be included in the qualification requirements of ASME AG-1

  10. Applying sequential Monte Carlo methods into a distributed hydrologic model: lagged particle filtering approach with regularization

    NASA Astrophysics Data System (ADS)

    Noh, S. J.; Tachikawa, Y.; Shiiba, M.; Kim, S.

    2011-04-01

    Applications of data assimilation techniques have been widely used to improve hydrologic prediction. Among various data assimilation techniques, sequential Monte Carlo (SMC) methods, known as "particle filters", provide the capability to handle non-linear and non-Gaussian state-space models. In this paper, we propose an improved particle filtering approach to consider different response time of internal state variables in a hydrologic model. The proposed method adopts a lagged filtering approach to aggregate model response until uncertainty of each hydrologic process is propagated. The regularization with an additional move step based on Markov chain Monte Carlo (MCMC) is also implemented to preserve sample diversity under the lagged filtering approach. A distributed hydrologic model, WEP is implemented for the sequential data assimilation through the updating of state variables. Particle filtering is parallelized and implemented in the multi-core computing environment via open message passing interface (MPI). We compare performance results of particle filters in terms of model efficiency, predictive QQ plots and particle diversity. The improvement of model efficiency and the preservation of particle diversity are found in the lagged regularized particle filter.

  11. Advanced configuration of hybrid passive filter for reactive power and harmonic compensation.

    PubMed

    Kececioglu, O Fatih; Acikgoz, Hakan; Sekkeli, Mustafa

    2016-01-01

    Harmonics is one of the major power quality problems for power systems. The harmonics can be eliminated by power filters such as passive, active, and hybrid. In this study, a new passive filter configuration has been improved in addition to the existing passive filter configurations. Conventional hybrid passive filters are not successful to compensate rapidly changing reactive power demand. The proposed configure are capable of compensating both harmonics and reactive power at the same time. Simulation results show that performance of reactive power and harmonic compensation with advanced hybrid passive filter is better than conventional hybrid passive filters.

  12. A particle filtering approach for spatial arrival time tracking in ocean acoustics.

    PubMed

    Jain, Rashi; Michalopoulou, Zoi-Heleni

    2011-06-01

    The focus of this work is on arrival time and amplitude estimation from acoustic signals recorded at spatially separated hydrophones in the ocean. A particle filtering approach is developed that treats arrival times as "targets" and tracks their "location" across receivers, also modeling arrival time gradient. The method is evaluated via Monte Carlo simulations and is compared to a maximum likelihood estimator, which does not relate arrivals at neighboring receivers. The comparison demonstrates a significant advantage in using the particle filter. It is also shown that posterior probability density functions of times and amplitudes become readily available with particle filtering.

  13. A novel permanently magnetised high gradient magnetic filter using assisted capture for fine particles

    SciTech Connect

    Watson, J.H.P.

    1995-02-01

    This paper describes the structure and properties of a novel permanently magnetised magnetic filter for fine friable radioactive material. Previously a filter was described and tested. This filter was designed so that the holes in the filter are left open as capture proceeds which means the pressure drop builds up only slowly. This filter is not suitable for friable composite particles which can be broken by mechanical forces. The structure of magnetic part of the second filter has been changed so as to strongly capture particles composed of fine particles weakly bound together which tend to break when captured. This uses a principle of assisted-capture in which coarse particles aid the capture of the fine fragments. The technique has the unfortunate consequence that the pressure drop across the filter rises faster as capture capture proceeds than the filter described previously. These filters have the following characteristics: (1) No external magnet is required. (2) No external power is required. (3) Small is size and portable. (4) Easily interchangeable. (5) Can be cleaned without demagnetising.

  14. PARTICLE TRANSPORTATION AND DEPOSITION IN HOT GAS FILTER VESSELS - A COMPUTATIONAL AND EXPERIMENTAL MODELING APPROACH

    SciTech Connect

    Goodarz Ahmadi

    2002-07-01

    In this project, a computational modeling approach for analyzing flow and ash transport and deposition in filter vessels was developed. An Eulerian-Lagrangian formulation for studying hot-gas filtration process was established. The approach uses an Eulerian analysis of gas flows in the filter vessel, and makes use of the Lagrangian trajectory analysis for the particle transport and deposition. Particular attention was given to the Siemens-Westinghouse filter vessel at Power System Development Facility in Wilsonville in Alabama. Details of hot-gas flow in this tangential flow filter vessel are evaluated. The simulation results show that the rapidly rotation flow in the spacing between the shroud and the vessel refractory acts as cyclone that leads to the removal of a large fraction of the larger particles from the gas stream. Several alternate designs for the filter vessel are considered. These include a vessel with a short shroud, a filter vessel with no shroud and a vessel with a deflector plate. The hot-gas flow and particle transport and deposition in various vessels are evaluated. The deposition patterns in various vessels are compared. It is shown that certain filter vessel designs allow for the large particles to remain suspended in the gas stream and to deposit on the filters. The presence of the larger particles in the filter cake leads to lower mechanical strength thus allowing for the back-pulse process to more easily remove the filter cake. A laboratory-scale filter vessel for testing the cold flow condition was designed and fabricated. A laser-based flow visualization technique is used and the gas flow condition in the laboratory-scale vessel was experimental studied. A computer model for the experimental vessel was also developed and the gas flow and particle transport patterns are evaluated.

  15. Homotopy Particle Filter for Ground-Based Tracking of Satellites at GEO

    NASA Astrophysics Data System (ADS)

    Moshtagh, N.; Chan, J.; Chan, M.

    2016-09-01

    Ground telescopes enable low-cost tracking and characterization of meter-class space objects. Since a telescope may be tasked to observe multiple fields of the sky, the time between observations for each object may vary from several seconds to tens of minutes. Long propagation times with nonlinear dynamics are challenging for traditional filtering methods such as the Extended Kalman Filter (EKF). Sampling-based filters based on the Particle Filter (PF) are promising for this type of problem but typically require maintaining a large number of samples. In this work, we evaluate the Homotopy Particle Filter (HPF) which promises effective performance with orders of magnitude fewer particles. The performance of the HPF is evaluated against GEO satellite observations collected by a ground telescope at Lockheed Martin's Space Object Tracking (SPOT) facility.

  16. Array of micro-machined mass energy micro-filters for charged particles

    NASA Technical Reports Server (NTRS)

    Stalder, Roland E. (Inventor); Van Zandt, Thomas R. (Inventor); Hecht, Michael H. (Inventor); Grunthaner, Frank J. (Inventor)

    1996-01-01

    An energy filter for charged particles includes a stack of micro-machined wafers including plural apertures passing through the stack of wafers, focusing electrodes bounding charged particle paths through the apertures, an entrance orifice to each of the plural apertures and an exit orifice from each of the plural apertures and apparatus for biasing the focusing electrodes with an electrostatic potential corresponding to an energy pass band of the filter.

  17. Advance particle and Doppler measurement methods

    NASA Technical Reports Server (NTRS)

    Busch, C.

    1985-01-01

    Particle environments, i.e., rain, ice, and snow particles are discussed. Two types of particles addressed are: (1) the natural environment in which airplanes fly and conduct test flights; and (2) simulation environments that are encountered in ground-test facilities such as wind tunnels, ranges, etc. There are characteristics of the natural environment that one wishes to measure. The liquid water content (LWC) is the one that seems to be of most importance; size distribution may be of importance in some applications. Like snow, the shape of the particle may be an important parameter to measure. As one goes on to environment in simulated tests, additional parameters may be required such as velocity distribution, the velocity lag of the particle relative to the aerodynamic flow, and the trajectory of the particle as it goes through the aerodynamic flow and impacts on the test object.

  18. Assessing consumption of bioactive micro-particles by filter-feeding Asian carp

    USGS Publications Warehouse

    Jensen, Nathan R.; Amberg, Jon J.; Luoma, James A.; Walleser, Liza R.; Gaikowski, Mark P.

    2012-01-01

    Silver carp Hypophthalmichthys molitrix (SVC) and bighead carp H. nobilis (BHC) have impacted waters in the US since their escape. Current chemical controls for aquatic nuisance species are non-selective. Development of a bioactive micro-particle that exploits filter-feeding habits of SVC or BHC could result in a new control tool. It is not fully understood if SVC or BHC will consume bioactive micro-particles. Two discrete trials were performed to: 1) evaluate if SVC and BHC consume the candidate micro-particle formulation; 2) determine what size they consume; 3) establish methods to evaluate consumption of filter-feeders for future experiments. Both SVC and BHC were exposed to small (50-100 μm) and large (150-200 μm) micro-particles in two 24-h trials. Particles in water were counted electronically and manually (microscopy). Particles on gill rakers were counted manually and intestinal tracts inspected for the presence of micro-particles. In Trial 1, both manual and electronic count data confirmed reductions of both size particles; SVC appeared to remove more small particles than large; more BHC consumed particles; SVC had fewer overall particles in their gill rakers than BHC. In Trial 2, electronic counts confirmed reductions of both size particles; both SVC and BHC consumed particles, yet more SVC consumed micro-particles compared to BHC. Of the fish that ate micro-particles, SVC consumed more than BHC. It is recommended to use multiple metrics to assess consumption of candidate micro-particles by filter-feeders when attempting to distinguish differential particle consumption. This study has implications for developing micro-particles for species-specific delivery of bioactive controls to help fisheries, provides some methods for further experiments with bioactive micro-particles, and may also have applications in aquaculture.

  19. Application of the implicit particle filter to a model of nearshore circulation

    NASA Astrophysics Data System (ADS)

    Miller, R. N.; Ehret, L. L.

    2014-04-01

    The implicit particle filter is applied to a stochastically forced shallow water model of nearshore flow, and found to produce reliable state estimates with tens of particles. The state vector of this model consists of a height anomaly and two horizontal velocity components at each point on a 128 × 98 regular rectangular grid, making for a state dimension O(104). The particle filter was applied to the model with two parameter choices representing two distinct dynamical regimes, and performed well in both. Demands on computing resources were manageable. Simulations with as many as a hundred particles ran overnight on a modestly configured workstation. In this case of observations defined by a linear function of the state vector, taken every time step of the numerical model, the implicit particle filter is equivalent to the optimal importance filter, i.e., at each step any given particle is drawn from the density of the system conditioned jointly upon observations and the state of that particle at the previous time. Even in this ideal case, the sample occasionally collapses to a single particle, and resampling is necessary. In those cases, the sample rapidly reinflates, and the analysis never loses track. In both dynamical regimes, the ensembles of particles deviated significantly from normality.

  20. Particle and Kalman filtering for state estimation and control of DC motors.

    PubMed

    Rigatos, Gerasimos G

    2009-01-01

    State estimation is a major problem in industrial systems. To this end, Gaussian and nonparametric filters have been developed. In this paper the Kalman Filter, which assumes Gaussian measurement noise, is compared to the Particle Filter, which does not make any assumption on the measurement noise distribution. As a case study the estimation of the state vector of a DC motor is used. The reconstructed state vector is used in a feedback control loop to generate the control input of the DC motor. In simulation tests it was observed that for a large number of particles the Particle Filter could succeed in accurately estimating the motor's state vector, but at the same time it required higher computational effort.

  1. Ensemble Kalman Filter vs Particle Filter in a Physically Based Coupled Model of Surface-Subsurface Flow (Invited)

    NASA Astrophysics Data System (ADS)

    Putti, M.; Camporese, M.; Pasetto, D.

    2010-12-01

    Data assimilation (DA) has recently received growing interest by the hydrological modeling community due to its capability to merge observations into model prediction. Among the many DA methods available, the Ensemble Kalman Filter (EnKF) and the Particle Filter (PF) are suitable alternatives for applications to detailed physically-based hydrological models. For each assimilation period, both methods use a Monte Carlo approach to approximate the state probability distribution (in terms of mean and covariance matrix) by a finite number of independent model trajectories, also called particles or realizations. The two approaches differ in the way the filtering distribution is evaluated. EnKF implements the classical Kalman filter, optimal only for linear dynamics and Gaussian error statistics. Particle filters, instead, use directly the recursive formula of the sequential Bayesian framework and approximate the posterior probability distributions by means of appropriate weights associated to each realization. We use the Sequential Importance Resampling (SIR) technique, which retains only the most probable particles, in practice the trajectories closest in a statistical sense to the observations, and duplicates them when needed. In contrast to EnKF, particle filters make no assumptions on the form of the prior distribution of the model state, and convergence to the true state is ensured for large enough ensemble size. In this study EnKF and PF have been implemented in a physically based catchment simulator that couples a three-dimensional finite element Richards equation solver with a finite difference diffusion wave approximation based on a digital elevation data for surface water dynamics. We report on the retrieval performance of the two schemes using a three-dimensional tilted v-catchment synthetic test case in which multi-source observations are assimilated (pressure head, soil moisture, and streamflow data). The comparison between the results of the two approaches

  2. NASAL FILTERING OF FINE PARTICLES IN CHILDREN VS. ADULTS

    EPA Science Inventory

    Nasal efficiency for removing fine particles may be affected by developmental changes in nasal structure associated with age. In healthy Caucasian children (age 6-13, n=17) and adults (age 18-28, n=11) we measured the fractional deposition (DF) of fine particles (1 and 2um MMAD)...

  3. [Particle load in intensive therapy. Possible solutions using a multi-lumen catheter and Intrapur filter].

    PubMed

    Schröder, F

    1990-06-01

    Patients at intensive care units need very many drugs applicated via a central venous katheter. Particles caused by incompatibility reactions or coming from disposible materials possibly can provoke severe complications such as embolism, anaphylactoid reactions or ARDS. The combined use of multilumen katheters and Intrapur filters brings a significant reduction of these particles, as shown by an infusion regime.

  4. Particle Density Using Deposition Filters at the Full Scale RDD Experiments.

    PubMed

    Berg, Rodney; Gilhuly, Colleen; Korpach, Ed; Ungar, Kurt

    2016-05-01

    During the Full-Scale Radiological Dispersal Device (FSRDD) Field Trials carried out in Suffield, Alberta, Canada, several suites of detection equipment and software models were used to measure and characterize the ground deposition. The FSRDD Field Trials were designed to disperse radioactive lanthanum of known activity to better understand such an event. This paper focuses on one means of measuring both concentration and the particle size distribution of the deposition using electrostatic filters placed around the trial site to collect deposited particles for analysis. The measurements made from ground deposition filters provided a basis to guide modeling and validate results by giving insight on how particles are distributed by a plume.

  5. 3D passive photon counting automatic target recognition using advanced correlation filters.

    PubMed

    Cho, Myungjin; Mahalanobis, Abhijit; Javidi, Bahram

    2011-03-15

    In this Letter, we present results for detecting and recognizing 3D objects in photon counting images using integral imaging with maximum average correlation height filters. We show that even under photon starved conditions objects may be automatically recognized in passively sensed 3D images using advanced correlation filters. We show that the proposed filter synthesized with ideal training images can detect and recognize a 3D object in photon counting images, even in the presence of occlusions and obscuration.

  6. Assessment of Metal Media Filters for Advanced Coal-Based Power Generation Applications

    SciTech Connect

    Alvin, M.A.

    2002-09-19

    Advanced coal and biomass-based gas turbine power generation technologies (IGCC, PFBC, PCFBC, and Hipps) are currently under development and demonstration. Efforts at Siemens Westinghouse Power Corporation (SWPC) have been focused on the development and demonstration of hot gas filter systems as an enabling technology for power generation. This paper reviews SWPC's material and component assessment efforts, identifying the performance, stability, and life of porous metal, advanced alloy, and intermetallic filters under simulated, pressurized fluidized-bed combustion conditions.

  7. A Gaussian process guided particle filter for tracking 3D human pose in video.

    PubMed

    Sedai, Suman; Bennamoun, Mohammed; Huynh, Du Q

    2013-11-01

    In this paper, we propose a hybrid method that combines Gaussian process learning, a particle filter, and annealing to track the 3D pose of a human subject in video sequences. Our approach, which we refer to as annealed Gaussian process guided particle filter, comprises two steps. In the training step, we use a supervised learning method to train a Gaussian process regressor that takes the silhouette descriptor as an input and produces multiple output poses modeled by a mixture of Gaussian distributions. In the tracking step, the output pose distributions from the Gaussian process regression are combined with the annealed particle filter to track the 3D pose in each frame of the video sequence. Our experiments show that the proposed method does not require initialization and does not lose tracking of the pose. We compare our approach with a standard annealed particle filter using the HumanEva-I dataset and with other state of the art approaches using the HumanEva-II dataset. The evaluation results show that our approach can successfully track the 3D human pose over long video sequences and give more accurate pose tracking results than the annealed particle filter.

  8. Development of a filter regeneration system for advanced spacecraft fluid systems

    NASA Technical Reports Server (NTRS)

    Behrend, A. F., Jr.; Descamp, V. A.

    1974-01-01

    The development of a filter regeneration system for efficiently cleaning fluid particulate filters is presented. Based on a backflush/jet impingement technique, the regeneration system demonstrated a cleaning efficiency of 98.7 to 100%. The operating principles and design features are discussed with emphasis on the primary system components that include a regenerable filter, vortex particle separator, and zero-g particle trap. Techniques and equipment used for ground and zero-g performance tests are described. Test results and conclusions, as well as possible areas for commercial application, are included.

  9. Analysis of video-based microscopic particle trajectories using Kalman filtering.

    PubMed

    Wu, Pei-Hsun; Agarwal, Ashutosh; Hess, Henry; Khargonekar, Pramod P; Tseng, Yiider

    2010-06-16

    The fidelity of the trajectories obtained from video-based particle tracking determines the success of a variety of biophysical techniques, including in situ single cell particle tracking and in vitro motility assays. However, the image acquisition process is complicated by system noise, which causes positioning error in the trajectories derived from image analysis. Here, we explore the possibility of reducing the positioning error by the application of a Kalman filter, a powerful algorithm to estimate the state of a linear dynamic system from noisy measurements. We show that the optimal Kalman filter parameters can be determined in an appropriate experimental setting, and that the Kalman filter can markedly reduce the positioning error while retaining the intrinsic fluctuations of the dynamic process. We believe the Kalman filter can potentially serve as a powerful tool to infer a trajectory of ultra-high fidelity from noisy images, revealing the details of dynamic cellular processes.

  10. Individual Particle Analysis of Ambient PM 2.5 Using Advanced Electron Microscopy Techniques

    SciTech Connect

    Gerald J. Keeler; Masako Morishita

    2006-12-31

    The overall goal of this project was to demonstrate a combination of advanced electron microscopy techniques that can be effectively used to identify and characterize individual particles and their sources. Specific techniques to be used include high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), STEM energy dispersive X-ray spectrometry (EDX), and energy-filtered TEM (EFTEM). A series of ambient PM{sub 2.5} samples were collected in communities in southwestern Detroit, MI (close to multiple combustion sources) and Steubenville, OH (close to several coal fired utility boilers). High-resolution TEM (HRTEM) -imaging showed a series of nano-metal particles including transition metals and elemental composition of individual particles in detail. Submicron and nano-particles with Al, Fe, Ti, Ca, U, V, Cr, Si, Ba, Mn, Ni, K and S were observed and characterized from the samples. Among the identified nano-particles, combinations of Al, Fe, Si, Ca and Ti nano-particles embedded in carbonaceous particles were observed most frequently. These particles showed very similar characteristics of ultrafine coal fly ash particles that were previously reported. By utilizing HAADF-STEM, STEM-EDX, and EF-TEM, this investigation was able to gain information on the size, morphology, structure, and elemental composition of individual nano-particles collected in Detroit and Steubenville. The results showed that the contributions of local combustion sources - including coal fired utilities - to ultrafine particle levels were significant. Although this combination of advanced electron microscopy techniques by itself can not identify source categories, these techniques can be utilized as complementary analytical tools that are capable of providing detailed information on individual particles.

  11. Multispectral Filter Arrays: Recent Advances and Practical Implementation

    PubMed Central

    Lapray, Pierre-Jean; Wang, Xingbo; Thomas, Jean-Baptiste; Gouton, Pierre

    2014-01-01

    Thanks to some technical progress in interferencefilter design based on different technologies, we can finally successfully implement the concept of multispectral filter array-based sensors. This article provides the relevant state-of-the-art for multispectral imaging systems and presents the characteristics of the elements of our multispectral sensor as a case study. The spectral characteristics are based on two different spatial arrangements that distribute eight different bandpass filters in the visible and near-infrared area of the spectrum. We demonstrate that the system is viable and evaluate its performance through sensor spectral simulation. PMID:25407904

  12. Advanced Energy-Efficient Filtration: Fan Filter Unit

    SciTech Connect

    Xu, Tengfang

    2005-10-01

    The objective of this project is to provide assistance in development of a standard test procedure for fan-filter units, which are gaining popularity for use in California cleanrooms. In particular, LBNL carried out collaboration with various stakeholders in the industry and took a lead in developing a draft standard method for testing the energy performance of fan-filter units, and provided assistance to California public utility companies by testing the draft method in PG&E's testing facility. Through testing more units in the future with a robust standard method, baseline performance information can be developed for use in possible energy incentive programs.

  13. Characterization of Airborne Particles Collected from Car Engine Air Filters Using SEM and EDX Techniques.

    PubMed

    Heredia Rivera, Birmania; Gerardo Rodriguez, Martín

    2016-10-01

    Particulate matter accumulated on car engine air-filters (CAFs) was examined in order to investigate the potential use of these devices as efficient samplers for collecting street level air that people are exposed to. The morphology, microstructure, and chemical composition of a variety of particles were studied using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). The particulate matter accumulated by the CAFs was studied in two categories; the first was of removed particles by friction, and the second consisted of particles retained on the filters. Larger particles with a diameter of 74-10 µm were observed in the first category. In the second one, the detected particles had a diameter between 16 and 0.7 µm. These particles exhibited different morphologies and composition, indicating mostly a soil origin. The elemental composition revealed the presence of three groups: mineral (clay and asphalt), metallic (mainly Fe), and biological particles (vegetal and animal debris). The palynological analysis showed the presence of pollen grains associated with urban plants. These results suggest that CAFs capture a mixture of atmospheric particles, which can be analyzed in order to monitor urban air. Thus, the continuous availability of large numbers of filters and the retroactivity associated to the car routes suggest that these CAFs are very useful for studying the high traffic zones within a city.

  14. Characterization of Airborne Particles Collected from Car Engine Air Filters Using SEM and EDX Techniques

    PubMed Central

    Heredia Rivera, Birmania; Gerardo Rodriguez, Martín

    2016-01-01

    Particulate matter accumulated on car engine air-filters (CAFs) was examined in order to investigate the potential use of these devices as efficient samplers for collecting street level air that people are exposed to. The morphology, microstructure, and chemical composition of a variety of particles were studied using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). The particulate matter accumulated by the CAFs was studied in two categories; the first was of removed particles by friction, and the second consisted of particles retained on the filters. Larger particles with a diameter of 74–10 µm were observed in the first category. In the second one, the detected particles had a diameter between 16 and 0.7 µm. These particles exhibited different morphologies and composition, indicating mostly a soil origin. The elemental composition revealed the presence of three groups: mineral (clay and asphalt), metallic (mainly Fe), and biological particles (vegetal and animal debris). The palynological analysis showed the presence of pollen grains associated with urban plants. These results suggest that CAFs capture a mixture of atmospheric particles, which can be analyzed in order to monitor urban air. Thus, the continuous availability of large numbers of filters and the retroactivity associated to the car routes suggest that these CAFs are very useful for studying the high traffic zones within a city. PMID:27706087

  15. Iris recognition using Gabor filters optimized by the particle swarm algorithm

    NASA Astrophysics Data System (ADS)

    Tsai, Chung-Chih; Taur, Jin-Shiuh; Tao, Chin-Wang

    2009-04-01

    An efficient feature extraction algorithm based on optimized Gabor filters and a relative variation analysis approach is proposed for iris recognition. The Gabor filters are optimized by using the particle swarm algorithm to adjust the parameters. Moreover, a sequential scheme is developed to determine the number of filters in the optimal Gabor filter bank. In the preprocessing step, the lower part of the iris image is unwrapped and normalized to a rectangular block that is then decomposed by the optimal Gabor filters. After that, a simple encoding method is adopted to generate a compact iris code. Experimental results show that with a smaller iris code size, the proposed method can produce comparable performance to that of the existing iris recognition systems.

  16. Filter performance of n99 and n95 facepiece respirators against viruses and ultrafine particles.

    PubMed

    Eninger, Robert M; Honda, Takeshi; Adhikari, Atin; Heinonen-Tanski, Helvi; Reponen, Tiina; Grinshpun, Sergey A

    2008-07-01

    The performance of three filtering facepiece respirators (two models of N99 and one N95) challenged with an inert aerosol (NaCl) and three virus aerosols (enterobacteriophages MS2 and T4 and Bacillus subtilis phage)-all with significant ultrafine components-was examined using a manikin-based protocol with respirators sealed on manikins. Three inhalation flow rates, 30, 85, and 150 l min(-1), were tested. The filter penetration and the quality factor were determined. Between-respirator and within-respirator comparisons of penetration values were performed. At the most penetrating particle size (MPPS), >3% of MS2 virions penetrated through filters of both N99 models at an inhalation flow rate of 85 l min(-1). Inhalation airflow had a significant effect upon particle penetration through the tested respirator filters. The filter quality factor was found suitable for making relative performance comparisons. The MPPS for challenge aerosols was <0.1 mum in electrical mobility diameter for all tested respirators. Mean particle penetration (by count) was significantly increased when the size fraction of <0.1 mum was included as compared to particles >0.1 mum. The filtration performance of the N95 respirator approached that of the two models of N99 over the range of particle sizes tested ( approximately 0.02 to 0.5 mum). Filter penetration of the tested biological aerosols did not exceed that of inert NaCl aerosol. The results suggest that inert NaCl aerosols may generally be appropriate for modeling filter penetration of similarly sized virions.

  17. Absorption coefficient measurements of particle-laden filters using laser heating: Validation with nigrosin

    NASA Astrophysics Data System (ADS)

    Presser, Cary

    2012-05-01

    A laser-heating technique, referred as the laser-driven thermal reactor, was used in conjunction with laser transmissivity measurements to determine the absorption coefficient of particle-laden substrates (e.g., quartz-fiber filters). The novelty of this approach is that it analyzes a wide variety of specific samples (not just filtered samples) and overcomes measurement issues (e.g., absorption enhancement) associated with other filter-based particle absorption techniques. The absorption coefficient was determined for nigrosin-laden, quartz-fiber filters and the effect of the filter on the absorption measurements was estimated when compared to the isolated nigrosin results. The isolated nigrosin absorption coefficient compared favorably with Lorenz-Mie calculations for an idealized polydispersion of spherical particles (based on a measured nigronsin/de-ionized water suspension size distribution) dispersed throughout a volume equivalent to that of the nigrosin-laden filter. To validate the approach, the absorption coefficient of a nigrosin/de-ionized water suspension was in good agreement with results obtained from an ultraviolet/visible spectrometer. In addition, the estimated imaginary part of the refractive index from the Lorenz-Mie calculations compared well with literature values and was used to estimate the absorption coefficient of optically opaque packed nigrosin.

  18. Material characterization of the clay bonded silicon carbide candle filters and ash formations in the W-APF system after 500 hours of hot gas filtration at AEP. Appendix to Advanced Particle Filter: Technical progress report No. 11, January--March 1993

    SciTech Connect

    Alvin, M.A.

    1993-04-05

    (1) After 500 hours of operation in the pressurized fluidized-bed combustion gas environment, the fibrous outer membrane along the clay bonded silicon carbide Schumacher Dia Schumalith candles remained intact. The fibrous outer membrane did not permit penetration of fines through the filter wall. (2) An approximate 10-15% loss of material strength occurred within the intact candle clay bonded silicon carbide matrix after 500 hours of exposure to the PFBC gas environment. A relatively uniform strength change resulted within the intact candles throughout the vessel (i.e., top to bottom plenums), as well as within the various cluster ring positions (i.e., outer versus inner ring candle filters). A somewhat higher loss of material strength, i.e., 25% was detected in fractured candle segments removed from the W-APF ash hopper. (3) Sulfur which is present in the pressurized fluidized-bed combustion gas system induced phase changes along the surface of the binder which coats the silicon carbide grains in the Schumacher Dia Schumalith candle filter matrix.

  19. Advanced Trickling Filters. Training Module 2.112.4.77.

    ERIC Educational Resources Information Center

    Layton, Ronald F.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with operation and maintenance of a trickling filter wastewater treatment plant. Included are objectives, instructor guides, student handouts and transparency masters. This is the third level of a three module series and considers…

  20. Advanced Crew Escape Suits (ACES): Particle Impact Test

    NASA Technical Reports Server (NTRS)

    Rosales, Keisa R.; Stoltzfus, Joel M.

    2009-01-01

    NASA Johnson Space Center (JSC) requested NASA JSC White Sands Test Facility to assist in determining the effects of impaired anodization on aluminum parts in advanced crew escape suits (ACES). Initial investigation indicated poor anodization could lead to an increased risk of particle impact ignition, and a lack of data was prevalent for particle impact of bare (unanodized) aluminum; therefore, particle impact tests were performed. A total of 179 subsonic and 60 supersonic tests were performed with no ignition of the aluminum targets. Based on the resulting test data, WSTF found no increased particle impact hazard was present in the ACES equipment.

  1. Evaluation of filter media for particle number, surface area and mass penetrations.

    PubMed

    Li, Lin; Zuo, Zhili; Japuntich, Daniel A; Pui, David Y H

    2012-07-01

    The National Institute for Occupational Safety and Health (NIOSH) developed a standard for respirator certification under 42 CFR Part 84, using a TSI 8130 automated filter tester with photometers. A recent study showed that photometric detection methods may not be sensitive for measuring engineered nanoparticles. Present NIOSH standards for penetration measurement are mass-based; however, the threshold limit value/permissible exposure limit for an engineered nanoparticle worker exposure is not yet clear. There is lack of standardized filter test development for engineered nanoparticles, and development of a simple nanoparticle filter test is indicated. To better understand the filter performance against engineered nanoparticles and correlations among different tests, initial penetration levels of one fiberglass and two electret filter media were measured using a series of polydisperse and monodisperse aerosol test methods at two different laboratories (University of Minnesota Particle Technology Laboratory and 3M Company). Monodisperse aerosol penetrations were measured by a TSI 8160 using NaCl particles from 20 to 300 nm. Particle penetration curves and overall penetrations were measured by scanning mobility particle sizer (SMPS), condensation particle counter (CPC), nanoparticle surface area monitor (NSAM), and TSI 8130 at two face velocities and three layer thicknesses. Results showed that reproducible, comparable filtration data were achieved between two laboratories, with proper control of test conditions and calibration procedures. For particle penetration curves, the experimental results of monodisperse testing agreed well with polydisperse SMPS measurements. The most penetrating particle sizes (MPPSs) of electret and fiberglass filter media were ~50 and 160 nm, respectively. For overall penetrations, the CPC and NSAM results of polydisperse aerosols were close to the penetration at the corresponding median particle sizes. For each filter type, power

  2. Workshop on advances in smooth particle hydrodynamics

    SciTech Connect

    Wingate, C.A.; Miller, W.A.

    1993-12-31

    This proceedings contains viewgraphs presented at the 1993 workshop held at Los Alamos National Laboratory. Discussed topics include: negative stress, reactive flow calculations, interface problems, boundaries and interfaces, energy conservation in viscous flows, linked penetration calculations, stability and consistency of the SPH method, instabilities, wall heating and conservative smoothing, tensors, tidal disruption of stars, breaking the 10,000,000 particle limit, modelling relativistic collapse, SPH without H, relativistic KSPH avoidance of velocity based kernels, tidal compression and disruption of stars near a supermassive rotation black hole, and finally relativistic SPH viscosity and energy.

  3. Kalman filter with a linear state model for PDR+WLAN positioning and its application to assisting a particle filter

    NASA Astrophysics Data System (ADS)

    Raitoharju, Matti; Nurminen, Henri; Piché, Robert

    2015-12-01

    Indoor positioning based on wireless local area network (WLAN) signals is often enhanced using pedestrian dead reckoning (PDR) based on an inertial measurement unit. The state evolution model in PDR is usually nonlinear. We present a new linear state evolution model for PDR. In simulated-data and real-data tests of tightly coupled WLAN-PDR positioning, the positioning accuracy with this linear model is better than with the traditional models when the initial heading is not known, which is a common situation. The proposed method is computationally light and is also suitable for smoothing. Furthermore, we present modifications to WLAN positioning based on Gaussian coverage areas and show how a Kalman filter using the proposed model can be used for integrity monitoring and (re)initialization of a particle filter.

  4. Removal of virus to protozoan sized particles in point-of-use ceramic water filters.

    PubMed

    Bielefeldt, Angela R; Kowalski, Kate; Schilling, Cherylynn; Schreier, Simon; Kohler, Amanda; Scott Summers, R

    2010-03-01

    The particle removal performance of point-of-use ceramic water filters (CWFs) was characterized in the size range of 0.02-100 microm using carboxylate-coated polystyrene fluorescent microspheres, natural particles and clay. Particles were spiked into dechlorinated tap water, and three successive water batches treated in each of six different CWFs. Particle removal generally increased with increasing size. The removal of virus-sized 0.02 and 0.1 microm spheres were highly variable between the six filters, ranging from 63 to 99.6%. For the 0.5 microm spheres removal was less variable and in the range of 95.1-99.6%, while for the 1, 2, 4.5, and 10 microm spheres removal was >99.6%. Recoating four of the CWFs with colloidal silver solution improved removal of the 0.02 microm spheres, but had no significant effects on the other particle sizes. Log removals of 1.8-3.2 were found for natural turbidity and spiked kaolin clay particles; however, particles as large as 95 microm were detected in filtered water.

  5. Combined assimilation of streamflow and satellite soil moisture with the particle filter and geostatistical modeling

    NASA Astrophysics Data System (ADS)

    Yan, Hongxiang; Moradkhani, Hamid

    2016-08-01

    Assimilation of satellite soil moisture and streamflow data into a distributed hydrologic model has received increasing attention over the past few years. This study provides a detailed analysis of the joint and separate assimilation of streamflow and Advanced Scatterometer (ASCAT) surface soil moisture into a distributed Sacramento Soil Moisture Accounting (SAC-SMA) model, with the use of recently developed particle filter-Markov chain Monte Carlo (PF-MCMC) method. Performance is assessed over the Salt River Watershed in Arizona, which is one of the watersheds without anthropogenic effects in Model Parameter Estimation Experiment (MOPEX). A total of five data assimilation (DA) scenarios are designed and the effects of the locations of streamflow gauges and the ASCAT soil moisture on the predictions of soil moisture and streamflow are assessed. In addition, a geostatistical model is introduced to overcome the significantly biased satellite soil moisture and also discontinuity issue. The results indicate that: (1) solely assimilating outlet streamflow can lead to biased soil moisture estimation; (2) when the study area can only be partially covered by the satellite data, the geostatistical approach can estimate the soil moisture for those uncovered grid cells; (3) joint assimilation of streamflow and soil moisture from geostatistical modeling can further improve the surface soil moisture prediction. This study recommends that the geostatistical model is a helpful tool to aid the remote sensing technique and the hydrologic DA study.

  6. Distributed Multi Robot Simultaneous Localization and Mapping with Consensus Particle Filtering

    NASA Astrophysics Data System (ADS)

    Hidayat, F.; Trilaksono, B. R.; Hindersah, H.

    2017-01-01

    These paper present distributed computations of join probabilities SLAM with consensus particle filtering algorithm. We consider groups of robot observe an unknown environment and build the global maps. In this paper, every local map is a global map. Global maps build by using its own information and the information obtained from the other robots. We use particles likelihood as transfer parameters. The information can be transferred to other robot if reach global agreement on particles weight. The global agreement can be obtained by using the Consensus Particle Filtering algorithm, computation is done locally on each robot. After reaching an agreement, then the global map can be built and information of the global map is owned on each robot.

  7. Lifted linear phase filter banks and the polyphase-with-advance representation

    SciTech Connect

    Brislawn, C. M.; Wohlberg, B. E.

    2004-01-01

    A matrix theory is developed for the noncausal polyphase-with-advance representation that underlies the theory of lifted perfect reconstruction filter banks and wavelet transforms as developed by Sweldens and Daubechies. This theory provides the fundamental lifting methodology employed in the ISO/IEC JPEG-2000 still image coding standard, which the authors helped to develop. Lifting structures for polyphase-with-advance filter banks are depicted in Figure 1. In the analysis bank of Figure 1(a), the first lifting step updates x{sub 0} with a filtered version of x{sub 1} and the second step updates x{sub 1} with a filtered version of x{sub 0}; gain factors 1/K and K normalize the lowpass- and highpass-filtered output subbands. Each of these steps is inverted by the corresponding operations in the synthesis bank shown in Figure 1(b). Lifting steps correspond to upper- or lower-triangular matrices, S{sub i}(z), in a cascade-form decomposition of the polyphase analysis matrix, H{sub a}(z). Lifting structures can also be implemented reversibly (i.e., losslessly in fixed-precision arithmetic) by rounding the lifting updates to integer values. Our treatment of the polyphase-with-advance representation develops an extensive matrix algebra framework that goes far beyond the results of. Specifically, we focus on analyzing and implementing linear phase two-channel filter banks via linear phase lifting cascade schemes. Whole-sample symmetric (WS) and half-sample symmetric (HS) linear phase filter banks are characterized completely in terms of the polyphase-with-advance representation. The theory benefits significantly from a number of new group-theoretic structures arising in the polyphase-with-advance matrix algebra from the lifting factorization of linear phase filter banks.

  8. Particle size distribution in effluent of trickling filters and in humus tanks.

    PubMed

    Schubert, W; Günthert, F W

    2001-11-01

    Particles and aggregates from trickling filters must be eliminated from wastewater. Usually this happens through sedimentation in humus tanks. Investigations to characterize these solids by way of particle size measurements, image analysis and particle charge measurements (zeta potential) are made within the scope of Research Center for Science and Technology "Fundamentals of Aerobic biological wastewater treatment" (SFB 411). The particle size measuring results given within this report were obtained at the Ingolstadt wastewater treatment plant, Germany, which served as an example. They have been confirmed by similar results from other facilities. Particles flushed out from trickling filters will be partially destroyed on their way to the humus tank. A large amount of small particles is to be found there. On average 90% of the particles are smaller than 30 microm. Particle size plays a decisive role in the sedimentation behaviour of solids. Small particles need sedimentation times that cannot be provided in settling tanks. As a result they cause turbidity in the final effluent. Therefore quality of sewage discharge suffers, and there are hardly advantages of the fixed film reactor treatment compared to the activated sludge process regarding sedimentation behaviour.

  9. Antibacterial performance of nano polypropylene filter media containing nano-TiO2 and clay particles

    NASA Astrophysics Data System (ADS)

    Shafiee, Sara; Zarrebini, Mohammad; Naghashzargar, Elham; Semnani, Dariush

    2015-10-01

    Disinfection and elimination of pathogenic microorganisms from liquid can be achieved by filtration process using antibacterial filter media. The advent of nanotechnology has facilitated the introduction of membranes consisting of nano-fiber in filtration operations. The melt electro-spun fibers due to their extremely small diameters are used in the production of this particular filtration medium. In this work, antibacterial polypropylene filter medium containing clay particles and nano-TiO2 were made using melt electro-spun technology. Antibacterial performance of polypropylene nano-filters was evaluated using E. coli bacteria. Additionally, filtration efficiency of the samples in terms fiber diameter, filter porosity, and fiber distribution using image processing technique was determined. Air permeability and dust aerosol tests were conducted to establish the suitability of the samples as a filter medium. It was concluded that as far as antibacterial property is concerned, nano-fibers filter media containing clay particles are preferential to similar media containing TiO2 nanoparticles.

  10. Boundary filters for vector particles passing parity breaking domains

    SciTech Connect

    Kolevatov, S. S.; Andrianov, A. A.

    2014-07-23

    The electrodynamics supplemented with a Lorenz and CPT invariance violating Chern-Simons (CS) action (Carrol-Field-Jackiw electrodynamics) is studied when the parity-odd medium is bounded by a hyperplane separating it from the vacuum. The solutions in both half-spaces are carefully discussed and for space-like boundary stitched on the boundary with help of the Bogolubov transformations. The presence of two different Fock vacua is shown. The passage of photons and massive vector mesons through a boundary between the CS medium and the vacuum of conventional Maxwell electrodynamics is investigated. Effects of reflection from a boundary (up to the total one) are revealed when vector particles escape to vacuum and income from vacuum passing the boundary.

  11. Use of particle filters in an active control algorithm for noisy nonlinear structural dynamical systems

    NASA Astrophysics Data System (ADS)

    Sajeeb, R.; Manohar, C. S.; Roy, D.

    2007-09-01

    The problem of active control of nonlinear structural dynamical systems, in the presence of both process and measurement noises, is considered. The focus of the study is on the use of particle filters for state estimation in feedback control algorithms for nonlinear structures, when a limited number of noisy output measurements are available. The control design is done using the state-dependent Riccati equation (SDRE) method. The stochastic differential equations (SDEs) governing the dynamical systems are discretized using explicit forms of Ito-Taylor expansions. The Bayesian bootstrap filter and that based on sequential important sampling (SIS) are employed for state estimation. The simulation results show the feasibility of using particle filters and SDRE techniques in control of nonlinear structural dynamical systems.

  12. Computer Vision Tracking Using Particle Filters for 3D Position Estimation

    DTIC Science & Technology

    2014-03-27

    5 2.2 Photogrammetry ...focus on particle filters. 2.2 Photogrammetry Photogrammetry is the process of determining 3-D coordinates through images. The mathematical underpinnings...of photogrammetry are rooted in the 1480s with Leonardo da Vinci’s study of perspectives [8, p. 1]. However, digital photogrammetry did not emerge

  13. High-efficiency particulate air filter test stand and aerosol generator for particle loading studies.

    PubMed

    Arunkumar, R; Hogancamp, Kristina U; Parsons, Michael S; Rogers, Donna M; Norton, Olin P; Nagel, Brian A; Alderman, Steven L; Waggoner, Charles A

    2007-08-01

    This manuscript describes the design, characterization, and operational range of a test stand and high-output aerosol generator developed to evaluate the performance of 30 x 30 x 29 cm(3) nuclear grade high-efficiency particulate air (HEPA) filters under variable, highly controlled conditions. The test stand system is operable at volumetric flow rates ranging from 1.5 to 12 standard m(3)/min. Relative humidity levels are controllable from 5%-90% and the temperature of the aerosol stream is variable from ambient to 150 degrees C. Test aerosols are produced through spray drying source material solutions that are introduced into a heated stainless steel evaporation chamber through an air-atomizing nozzle. Regulation of the particle size distribution of the aerosol challenge is achieved by varying source solution concentrations and through the use of a postgeneration cyclone. The aerosol generation system is unique in that it facilitates the testing of standard HEPA filters at and beyond rated media velocities by consistently providing, into a nominal flow of 7 standard m(3)/min, high mass concentrations (approximately 25 mg/m(3)) of dry aerosol streams having count mean diameters centered near the most penetrating particle size for HEPA filters (120-160 nm). Aerosol streams that have been generated and characterized include those derived from various concentrations of KCl, NaCl, and sucrose solutions. Additionally, a water insoluble aerosol stream in which the solid component is predominantly iron (III) has been produced. Multiple ports are available on the test stand for making simultaneous aerosol measurements upstream and downstream of the test filter. Types of filter performance related studies that can be performed using this test stand system include filter lifetime studies, filtering efficiency testing, media velocity testing, evaluations under high mass loading and high humidity conditions, and determination of the downstream particle size distributions.

  14. Integration of GPS precise point positioning and MEMS-based INS using unscented particle filter.

    PubMed

    Abd Rabbou, Mahmoud; El-Rabbany, Ahmed

    2015-03-25

    Integration of Global Positioning System (GPS) and Inertial Navigation System (INS) integrated system involves nonlinear motion state and measurement models. However, the extended Kalman filter (EKF) is commonly used as the estimation filter, which might lead to solution divergence. This is usually encountered during GPS outages, when low-cost micro-electro-mechanical sensors (MEMS) inertial sensors are used. To enhance the navigation system performance, alternatives to the standard EKF should be considered. Particle filtering (PF) is commonly considered as a nonlinear estimation technique to accommodate severe MEMS inertial sensor biases and noise behavior. However, the computation burden of PF limits its use. In this study, an improved version of PF, the unscented particle filter (UPF), is utilized, which combines the unscented Kalman filter (UKF) and PF for the integration of GPS precise point positioning and MEMS-based inertial systems. The proposed filter is examined and compared with traditional estimation filters, namely EKF, UKF and PF. Tightly coupled mechanization is adopted, which is developed in the raw GPS and INS measurement domain. Un-differenced ionosphere-free linear combinations of pseudorange and carrier-phase measurements are used for PPP. The performance of the UPF is analyzed using a real test scenario in downtown Kingston, Ontario. It is shown that the use of UPF reduces the number of samples needed to produce an accurate solution, in comparison with the traditional PF, which in turn reduces the processing time. In addition, UPF enhances the positioning accuracy by up to 15% during GPS outages, in comparison with EKF. However, all filters produce comparable results when the GPS measurement updates are available.

  15. Integration of GPS Precise Point Positioning and MEMS-Based INS Using Unscented Particle Filter

    PubMed Central

    Abd Rabbou, Mahmoud; El-Rabbany, Ahmed

    2015-01-01

    Integration of Global Positioning System (GPS) and Inertial Navigation System (INS) integrated system involves nonlinear motion state and measurement models. However, the extended Kalman filter (EKF) is commonly used as the estimation filter, which might lead to solution divergence. This is usually encountered during GPS outages, when low-cost micro-electro-mechanical sensors (MEMS) inertial sensors are used. To enhance the navigation system performance, alternatives to the standard EKF should be considered. Particle filtering (PF) is commonly considered as a nonlinear estimation technique to accommodate severe MEMS inertial sensor biases and noise behavior. However, the computation burden of PF limits its use. In this study, an improved version of PF, the unscented particle filter (UPF), is utilized, which combines the unscented Kalman filter (UKF) and PF for the integration of GPS precise point positioning and MEMS-based inertial systems. The proposed filter is examined and compared with traditional estimation filters, namely EKF, UKF and PF. Tightly coupled mechanization is adopted, which is developed in the raw GPS and INS measurement domain. Un-differenced ionosphere-free linear combinations of pseudorange and carrier-phase measurements are used for PPP. The performance of the UPF is analyzed using a real test scenario in downtown Kingston, Ontario. It is shown that the use of UPF reduces the number of samples needed to produce an accurate solution, in comparison with the traditional PF, which in turn reduces the processing time. In addition, UPF enhances the positioning accuracy by up to 15% during GPS outages, in comparison with EKF. However, all filters produce comparable results when the GPS measurement updates are available. PMID:25815446

  16. Joint State and Parameter Estimation for Two Land Surface Models Using the Ensemble Kalman Filter and Particle Filter

    NASA Astrophysics Data System (ADS)

    Zhang, Hongjuan; Hendricks-Franssen, Harrie-Jan; Han, Xujun; Vrugt, Jasper A.; Vereecken, Harry

    2016-04-01

    Land surface models (LSMs) resolve the water and energy balance with different parameters and state variables. Many of the parameters of these models cannot be measured directly in the field, and require calibration against flux and soil moisture data. Two LSMs are used in our work: Variable Infiltration Capacity Hydrologic Model (VIC) and the Community Land Model (CLM). Temporal variations in soil moisture content at 5, 20 and 50 cm depth in the Rollesbroich experimental watershed in Germany are simulated in both LSMs. Data assimilation (DA) provides a good way to jointly estimate soil moisture content and soil properties of the resolved soil domain. Four DA methods combined with the two LSMs are used in our work: the Ensemble Kalman Filter (EnKF) using state augmentation or dual estimation, the Residual Resampling Particle Filter (RRPF) and Markov chain Monte Carlo Particle Filter (MCMCPF). These four DA methods are tuned and calibrated for a five month period, and subsequently evaluated for another five month period. Performances of the two LSMs and the four DA methods are compared. Our results show that all DA methods improve the estimation of soil moisture content of the VIC and CLM models, especially if the soil hydraulic properties (VIC), the maximum baseflow velocity (VIC) and/or soil texture (CLM) are jointly estimated with soil moisture content. The augmentation and dual estimation methods performed slightly better than RRPF and MCMCPF in the evaluation period. The differences in simulated soil moisture content between CLM and VIC were larger than variations among the DA methods. The CLM performed better than the VIC model. The strong underestimation of soil moisture content in the third layer of the VIC model is likely related to an inadequate parameterization of groundwater drainage.

  17. Station Based Polynomial Modeling of the local ionospheric Vertical Total Electron Content (VTEC) using Particle Filter

    NASA Astrophysics Data System (ADS)

    Erdogan, Eren; Onur Karslioglu, Mahmut; Durmaz, Murat; Aghakarimi, Armin

    2014-05-01

    In this study, particle filter (PF) which is mainly based on the Monte Carlo simulation technique has been carried out for polynomial modeling of the local ionospheric conditions above the selected ground based stations. Less sensitivity to the errors caused by linearization of models and the effect of unknown or unmodeled components in the system model is one of the advantages of the particle filter as compared to the Kalman filter which is commonly used as a recursive filtering method in VTEC modeling. Besides, probability distribution of the system models is not necessarily required to be Gaussian. In this work third order polynomial function has been incorporated into the particle filter implementation to represent the local VTEC distribution. Coefficients of the polynomial model presenting the ionospheric parameters and the receiver inter frequency biases are the unknowns forming the state vector which has been estimated epoch-wise for each ground station. To consider the time varying characteristics of the regional VTEC distribution, dynamics of the state vector parameters changing permanently have been modeled using the first order Gauss-Markov process. In the processing of the particle filtering, multi-variety probability distribution of the state vector through the time has been approximated by means of randomly selected samples and their associated weights. A known drawback of the particle filtering is that the increasing number of the state vector parameters results in an inefficient filter performance and requires more samples to represent the probability distribution of the state vector. Considering the total number of unknown parameters for all ground stations, estimation of these parameters which were inserted into a single state vector has caused the particle filter to produce inefficient results. To solve this problem, the PF implementation has been carried out separately for each ground station at current time epochs. After estimation of unknown

  18. Implicit particle filtering for equations with partial noise and application to geomagnetic data assimilation

    NASA Astrophysics Data System (ADS)

    Morzfeld, M.; Atkins, E.; Chorin, A. J.

    2011-12-01

    The task in data assimilation is to identify the state of a system from an uncertain model supplemented by a stream of incomplete and noisy data. The model is typically given in form of a discretization of an Ito stochastic differential equation (SDE), x(n+1) = R(x(n))+ G W(n), where x is an m-dimensional vector and n=0,1,2,.... The m-dimensional vector function R and the m x m matrix G depend on the SDE as well as on the discretization scheme, and W is an m-dimensional vector whose elements are independent standard normal variates. The data are y(n) = h(x(n))+QV(n) where h is a k-dimensional vector function, Q is a k x k matrix and V is a vector whose components are independent standard normal variates. One can use statistics of the conditional probability density (pdf) of the state given the observations, p(n+1)=p(x(n+1)|y(1), ... , y(n+1)), to identify the state x(n+1). Particle filters approximate p(n+1) by sequential Monte Carlo and rely on the recursive formulation of the target pdf, p(n+1)∝p(x(n+1)|x(n)) p(y(n+1)|x(n+1)). The pdf p(x(n+1)|x(n)) can be read off of the model equations to be a Gaussian with mean R(x(n)) and covariance matrix Σ = GG^T, where the T denotes a transposed; the pdf p(y(n+1)|x(n+1)) is a Gaussian with mean h(x(n+1)) and covariance QQ^T. In a sampling-importance-resampling (SIR) filter one samples new values for the particles from a prior pdf and then one weighs these samples with weights determined by the observations, to yield an approximation to p(n+1). Such weighting schemes often yield small weights for many of the particles. Implicit particle filtering overcomes this problem by using the observations to generate the particles, thus focusing attention on regions of large probability. A suitable algebraic equation that depends on the model and the observations is constructed for each particle, and its solution yields high probability samples of p(n+1). In the current formulation of the implicit particle filter, the state

  19. Particle capture in axial magnetic filters with power law flow model

    NASA Astrophysics Data System (ADS)

    Abbasov, T.; Herdem, S.; Köksal, M.

    1999-05-01

    A theory of capture of magnetic particle carried by laminar flow of viscous non-Newtonian (power law) fluid in axially ordered filters is presented. The velocity profile of the fluid flow is determined by the Kuwabara-Happel cell model. For the trajectory of the particle, the capture area and the filter performance simple analytical expressions are obtained. These expressions are valid for particle capture processes from both Newtonian and non-Newtonian fluids. For this reason the obtained theoretical results make it possible to widen the application of high-gradient magnetic filtration (HGMF) to other industrial areas. For Newtonian fluids the theoretical results are shown to be in good agreement with the experimental ones reported in the literature.

  20. Filtering capacity of Daphnia magna on sludge particles in treated wastewater.

    PubMed

    Pau, Conxi; Serra, Teresa; Colomer, Jordi; Casamitjana, Xavier; Sala, Lluís; Kampf, Ruud

    2013-01-01

    A great challenge in water reuse is the reduction of suspended particle concentration in wastewater. In particular the reduction of the presence of small particles in suspension which cause a cloudy appearance in the water and, which also make disinfection difficult. The present study evaluates the filtering capacity of a population of Cladodera (Daphnia magna) in secondary effluents from a wastewater plant. The study was performed in both a mesocosm and the laboratory, in an effort to compare the grazing on sludge particles by Daphnia versus the settling rate of those sludge particles. The particle volume concentration of small particles (with a diameter below 30 μm) was used to evaluate the efficiency of the proposed biotreatment system for small particles. Both laboratory and mesocosm results showed that the suspended particle volume concentration decreased with time due to the Daphnia filtration, with the highest reduction in experiments carried out with the highest Daphnia concentration. In the mesocosm experiments, the Daphnia diameter was also found to play an important role, with an allometric relationship between the filtering rate of Daphnia and the Daphnia nondimensional diameter. In laboratory experiments, the effect of D. magna in the suspended concentration of small particles was in the range of 10.1-29.4%, according to the range of Daphnia concentration of 10-50 ind/l. For laboratory experiments, sedimentation was responsible for 62.2% of the suspended particle concentration reduction. For the mesocosm experiments, the reduction in the particle concentration attributed to the Daphnia filtration ranged between 2.5 and 39%, corresponding to Daphnia concentrations of between 5 and 100 ind/l (i.e. biovolumes of 8-60 ind/l).

  1. Advanced hot-gas filter development. Topical report, September 30, 1994--May 31, 1996

    SciTech Connect

    Lane, J.E.; LeCostaouec, J.F.; Painter, C.J.; Sue, W.A.; Radford, K.C.

    1996-12-31

    The application of high-performance, high-temperature particulate control devices is considered to be beneficial to advanced fossil fuel processing technology, to selected high-temperature industrial processes, and to waste incineration concepts. Ceramic rigid filters represent the most attractive technology for these applications due to their capability to withstand high-temperature corrosive environments. However, current generation monolithic filters have demonstrated poor resistance to crack propagation and can experience catastrophic failure during use. To address this problem, ceramic fiber-reinforced ceramic matrix composite (CMC) filter materials are needed for reliable damage tolerant candle filters. This program is focused on the development of an oxide-fiber reinforced oxide material composite filter material that is cost competitive with prototype next generation filters. This goal would be achieved through the development of a low cost sol-gel fabrication process and a three-dimensional fiber architecture optimized for high volume filter manufacturing. The 3D continuous fiber reinforcement provides a damage tolerant structure which is not subject to delamination-type failures. This report documents the Phase 1, Filter Material Development and Evaluation, results. Section 2 provides a program summary. Technical results, including experimental procedures, are presented and discussed in Section 3. Section 4 and 5 provide the Phase 1 conclusions and recommendations, respectively. The remaining sections cover acknowledgements and references.

  2. Evaluation of the effect of media velocity on filter efficiency and most penetrating particle size of nuclear grade high-efficiency particulate air filters.

    PubMed

    Alderman, Steven L; Parsons, Michael S; Hogancamp, Kristina U; Waggoner, Charles A

    2008-11-01

    High-efficiency particulate air (HEPA) filters are widely used to control particulate matter emissions from processes that involve management or treatment of radioactive materials. Section FC of the American Society of Mechanical Engineers AG-1 Code on Nuclear Air and Gas Treatment currently restricts media velocity to a maximum of 2.5 cm/sec in any application where this standard is invoked. There is some desire to eliminate or increase this media velocity limit. A concern is that increasing media velocity will result in higher emissions of ultrafine particles; thus, it is unlikely that higher media velocities will be allowed without data to demonstrate the effect of media velocity on removal of ultrafine particles. In this study, the performance of nuclear grade HEPA filters, with respect to filter efficiency and most penetrating particle size, was evaluated as a function of media velocity. Deep-pleat nuclear grade HEPA filters (31 cm x 31 cm x 29 cm) were evaluated at media velocities ranging from 2.0 to 4.5 cm/sec using a potassium chloride aerosol challenge having a particle size distribution centered near the HEPA filter most penetrating particle size. Filters were challenged under two distinct mass loading rate regimes through the use of or exclusion of a 3 microm aerodynamic diameter cut point cyclone. Filter efficiency and most penetrating particle size measurements were made throughout the duration of filter testing. Filter efficiency measured at the onset of aerosol challenge was noted to decrease with increasing media velocity, with values ranging from 99.999 to 99.977%. The filter most penetrating particle size recorded at the onset of testing was noted to decrease slightly as media velocity was increased and was typically in the range of 110-130 nm. Although additional testing is needed, these findings indicate that filters operating at media velocities up to 4.5 cm/sec will meet or exceed current filter efficiency requirements. Additionally

  3. Continuous collection of soluble atmospheric particles with a wetted hydrophilic filter.

    PubMed

    Takeuchi, Masaki; Ullah, S M Rahmat; Dasgupta, Purnendu K; Collins, Donald R; Williams, Allen

    2005-12-15

    Approximately one-third of the area (14-mm diameter of a 25-mm diameter) of a 5-microm uniform pore size polycarbonate filter is continuously wetted by a 0.25 mL/min water mist. The water forms a continuous thin film on the filter and percolates through it. The flowing water substantially reduces the effective pore size of the filter. At the operational air sampling flow rate of 1.5 standard liters per minute, such a particle collector (PC) efficiently captures particles down to very small size. As determined by fluorescein-tagged NaCl aerosol generated by a vibrating orifice aerosol generator, the capture efficiency was 97.7+% for particle aerodynamic diameters ranging from 0.28 to 3.88 microm. Further, 55.3 and 80.3% of 25- and 100-nm (NH4)2SO4 particles generated by size classification with a differential mobility analyzer were respectively collected by the device. The PC is integrally coupled with a liquid collection reservoir. The liquid effluent from the wetted filter collector, bearing the soluble components of the aerosol, can be continuously collected or periodically withdrawn. The latter strategy permits the use of a robust syringe pump for the purpose. Coupled with a PM2.5 cyclone inlet and a membrane-based parallel plate denuder at the front end and an ion chromatograph at the back end, the PC readily operated for at least 4-week periods without filter replacement or any other maintenance.

  4. Variation in penetration of submicrometric particles through electrostatic filtering facepieces during exposure to paraffin oil aerosol.

    PubMed

    Plebani, Carmela; Listrani, Stefano; Tranfo, Giovanna; Tombolini, Francesca

    2012-01-01

    Several studies show the increase of penetration through electrostatic filters during exposure to an aerosol flow, because of particle deposition on filter fibers. We studied the effect of increasing loads of paraffin oil aerosol on the penetration of selected particle sizes through an electrostatic filtering facepiece. FFP2 facepieces were exposed for 8 hr to a flow rate of 95.0 ± 0.5 L/min of polydisperse paraffin aerosol at 20.0 ± 0.5 mg/m(3). The penetration of bis(2-ethylhexyl)sebacate (DEHS) monodisperse neutralized aerosols, with selected particle size in the 0.03-0.40 μm range, was measured immediately prior to the start of the paraffin aerosol loading and at 1, 4, and 8 hr after the start of paraffin aerosol loading. Penetration through isopropanol-treated facepieces not oil paraffin loaded was also measured to evaluate facepiece behavior when electrostatic capture mechanisms are practically absent. During exposure to paraffin aerosol, DEHS penetration gradually increased for all aerosol sizes, and the most penetrating particle size (0.05 μm at the beginning of exposure) shifted slightly to larger diameters. After the isopropanol treatment, the higher penetration value was 0.30 μm. In addition to an increased penetration during paraffin loading at a given particle size, the relative degree of increase was greater as the particle size increased. Penetration value measured after 8 hr for 0.03-μm particles was on average 1.6 times the initial value, whereas it was about 8 times for 0.40-μm particles. This behavior, as well evidenced in the measurements of isopropanol-treated facepieces, can be attributed to the increasing action in particle capture of the electrostatic forces (Coulomb and polarization), which depend strictly on the diameter and electrical charge of neutralized aerosol particles. With reference to electrostatic filtering facepieces as personal protective equipment, results suggest the importance of complying with the manufacturer

  5. Tracking Algorithm of Multiple Pedestrians Based on Particle Filters in Video Sequences

    PubMed Central

    Liu, Yun; Wang, Chuanxu; Zhang, Shujun; Cui, Xuehong

    2016-01-01

    Pedestrian tracking is a critical problem in the field of computer vision. Particle filters have been proven to be very useful in pedestrian tracking for nonlinear and non-Gaussian estimation problems. However, pedestrian tracking in complex environment is still facing many problems due to changes of pedestrian postures and scale, moving background, mutual occlusion, and presence of pedestrian. To surmount these difficulties, this paper presents tracking algorithm of multiple pedestrians based on particle filters in video sequences. The algorithm acquires confidence value of the object and the background through extracting a priori knowledge thus to achieve multipedestrian detection; it adopts color and texture features into particle filter to get better observation results and then automatically adjusts weight value of each feature according to current tracking environment. During the process of tracking, the algorithm processes severe occlusion condition to prevent drift and loss phenomena caused by object occlusion and associates detection results with particle state to propose discriminated method for object disappearance and emergence thus to achieve robust tracking of multiple pedestrians. Experimental verification and analysis in video sequences demonstrate that proposed algorithm improves the tracking performance and has better tracking results. PMID:27847514

  6. Tracking Algorithm of Multiple Pedestrians Based on Particle Filters in Video Sequences.

    PubMed

    Li, Hui; Liu, Yun; Wang, Chuanxu; Zhang, Shujun; Cui, Xuehong

    2016-01-01

    Pedestrian tracking is a critical problem in the field of computer vision. Particle filters have been proven to be very useful in pedestrian tracking for nonlinear and non-Gaussian estimation problems. However, pedestrian tracking in complex environment is still facing many problems due to changes of pedestrian postures and scale, moving background, mutual occlusion, and presence of pedestrian. To surmount these difficulties, this paper presents tracking algorithm of multiple pedestrians based on particle filters in video sequences. The algorithm acquires confidence value of the object and the background through extracting a priori knowledge thus to achieve multipedestrian detection; it adopts color and texture features into particle filter to get better observation results and then automatically adjusts weight value of each feature according to current tracking environment. During the process of tracking, the algorithm processes severe occlusion condition to prevent drift and loss phenomena caused by object occlusion and associates detection results with particle state to propose discriminated method for object disappearance and emergence thus to achieve robust tracking of multiple pedestrians. Experimental verification and analysis in video sequences demonstrate that proposed algorithm improves the tracking performance and has better tracking results.

  7. Improving the LPJ-GUESS modelled carbon balance with a particle filter data assimilation technique

    NASA Astrophysics Data System (ADS)

    McRobert, Andrew; Scholze, Marko; Kemp, Sarah; Smith, Ben

    2015-04-01

    The recent increases in anthropogenic carbon dioxide (CO_2) emissions have disrupted the equilibrium in the global carbon cycle pools with the ocean and terrestrial pools increasing their respective storages to accommodate roughly half of the anthropogenic increase. Dynamic global vegetation models (DGVM) have been developed to quantify the modern carbon cycle changes. In this study, a particle filter data assimilation technique has been used to calibrate the process parameters in the DGVM LPJ-GUESS (Lund-Potsdam-Jena General Ecosystem Simulator). LPJ-GUESS simulates individual plant function types (pft) as a competitive balance within high resolution forest patches. Thirty process parameters have been optimized twice, using both a sequential and iterative method of particle filter. The iterative method runs the model for the full time period of thirteen years and then evaluates the cost function from the mismatch of observations and model results before adjusting the parameters and repeating the full time period. The sequential method runs the model and particle filter for each year of the time series in order, adjusting the parameters between each year, then loops back to beginning of the series to repeat. For each particle, the model output of NEP (Net Ecosystem Productivity) is compared to eddy flux measurements from ICOS flux towers to minimize the cost function. A high-resolution regional carbon balance has been simulated for central Sweden using a network of several ICOS flux towers.

  8. Advances in Bayesian Model Based Clustering Using Particle Learning

    SciTech Connect

    Merl, D M

    2009-11-19

    Recent work by Carvalho, Johannes, Lopes and Polson and Carvalho, Lopes, Polson and Taddy introduced a sequential Monte Carlo (SMC) alternative to traditional iterative Monte Carlo strategies (e.g. MCMC and EM) for Bayesian inference for a large class of dynamic models. The basis of SMC techniques involves representing the underlying inference problem as one of state space estimation, thus giving way to inference via particle filtering. The key insight of Carvalho et al was to construct the sequence of filtering distributions so as to make use of the posterior predictive distribution of the observable, a distribution usually only accessible in certain Bayesian settings. Access to this distribution allows a reversal of the usual propagate and resample steps characteristic of many SMC methods, thereby alleviating to a large extent many problems associated with particle degeneration. Furthermore, Carvalho et al point out that for many conjugate models the posterior distribution of the static variables can be parametrized in terms of [recursively defined] sufficient statistics of the previously observed data. For models where such sufficient statistics exist, particle learning as it is being called, is especially well suited for the analysis of streaming data do to the relative invariance of its algorithmic complexity with the number of data observations. Through a particle learning approach, a statistical model can be fit to data as the data is arriving, allowing at any instant during the observation process direct quantification of uncertainty surrounding underlying model parameters. Here we describe the use of a particle learning approach for fitting a standard Bayesian semiparametric mixture model as described in Carvalho, Lopes, Polson and Taddy. In Section 2 we briefly review the previously presented particle learning algorithm for the case of a Dirichlet process mixture of multivariate normals. In Section 3 we describe several novel extensions to the original

  9. The new approach for infrared target tracking based on the particle filter algorithm

    NASA Astrophysics Data System (ADS)

    Sun, Hang; Han, Hong-xia

    2011-08-01

    Target tracking on the complex background in the infrared image sequence is hot research field. It provides the important basis in some fields such as video monitoring, precision, and video compression human-computer interaction. As a typical algorithms in the target tracking framework based on filtering and data connection, the particle filter with non-parameter estimation characteristic have ability to deal with nonlinear and non-Gaussian problems so it were widely used. There are various forms of density in the particle filter algorithm to make it valid when target occlusion occurred or recover tracking back from failure in track procedure, but in order to capture the change of the state space, it need a certain amount of particles to ensure samples is enough, and this number will increase in accompany with dimension and increase exponentially, this led to the increased amount of calculation is presented. In this paper particle filter algorithm and the Mean shift will be combined. Aiming at deficiencies of the classic mean shift Tracking algorithm easily trapped into local minima and Unable to get global optimal under the complex background. From these two perspectives that "adaptive multiple information fusion" and "with particle filter framework combining", we expand the classic Mean Shift tracking framework .Based on the previous perspective, we proposed an improved Mean Shift infrared target tracking algorithm based on multiple information fusion. In the analysis of the infrared characteristics of target basis, Algorithm firstly extracted target gray and edge character and Proposed to guide the above two characteristics by the moving of the target information thus we can get new sports guide grayscale characteristics and motion guide border feature. Then proposes a new adaptive fusion mechanism, used these two new information adaptive to integrate into the Mean Shift tracking framework. Finally we designed a kind of automatic target model updating strategy

  10. Design of reflective color filters with high angular tolerance by particle swarm optimization method.

    PubMed

    Yang, Chenying; Hong, Liang; Shen, Weidong; Zhang, Yueguang; Liu, Xu; Zhen, Hongyu

    2013-04-22

    We propose three color filters (red, green, blue) based on a two-dimensional (2D) grating, which maintain the same perceived specular colors for a broad range of incident angles with the average polarization. Particle swarm optimization (PSO) method is employed to design these filters for the first time to our knowledge. Two merit functions involving the reflectance curves and color difference in CIEDE2000 formula are respectively constructed to adjust the structural parameters during the optimization procedure. Three primary color filters located at 637nm, 530nm and 446nm with high saturation are obtained with the peak reflectance of 89%, 83%, 66%. The reflectance curves at different incident angles are coincident and the color difference is less than 8 for the incident angle up to 45°. The electric field distribution of the structure is finally studied to analyze the optical property.

  11. Combining Video, Audio and Lexical Indicators of Affect in Spontaneous Conversation via Particle Filtering

    PubMed Central

    Savran, Arman; Cao, Houwei; Shah, Miraj; Nenkova, Ani; Verma, Ragini

    2013-01-01

    We present experiments on fusing facial video, audio and lexical indicators for affect estimation during dyadic conversations. We use temporal statistics of texture descriptors extracted from facial video, a combination of various acoustic features, and lexical features to create regression based affect estimators for each modality. The single modality regressors are then combined using particle filtering, by treating these independent regression outputs as measurements of the affect states in a Bayesian filtering framework, where previous observations provide prediction about the current state by means of learned affect dynamics. Tested on the Audio-visual Emotion Recognition Challenge dataset, our single modality estimators achieve substantially higher scores than the official baseline method for every dimension of affect. Our filtering-based multi-modality fusion achieves correlation performance of 0.344 (baseline: 0.136) and 0.280 (baseline: 0.096) for the fully continuous and word level sub challenges, respectively. PMID:25300451

  12. Retention of radioactive particles and associated effects in the filter-feeding marine mollusc Mytilus edulis.

    PubMed

    Jaeschke, B C; Lind, O C; Bradshaw, C; Salbu, B

    2015-01-01

    Radioactive particles are aggregates of radioactive atoms that may contain significant activity concentrations. They have been released into the environment from nuclear weapons tests, and from accidents and effluents associated with the nuclear fuel cycle. Aquatic filter-feeders can capture and potentially retain radioactive particles, which could then provide concentrated doses to nearby tissues. This study experimentally investigated the retention and effects of radioactive particles in the blue mussel, Mytilus edulis. Spent fuel particles originating from the Dounreay nuclear establishment, and collected in the field, comprised a U and Al alloy containing fission products such as (137)Cs and (90)Sr/(90)Y. Particles were introduced into mussels in suspension with plankton-food or through implantation in the extrapallial cavity. Of the particles introduced with food, 37% were retained for 70 h, and were found on the siphon or gills, with the notable exception of one particle that was ingested and found in the stomach. Particles not retained seemed to have been actively rejected and expelled by the mussels. The largest and most radioactive particle (estimated dose rate 3.18 ± 0.06 Gyh(-1)) induced a significant increase in Comet tail-DNA %. In one case this particle caused a large white mark (suggesting necrosis) in the mantle tissue with a simultaneous increase in micronucleus frequency observed in the haemolymph collected from the muscle, implying that non-targeted effects of radiation were induced by radiation from the retained particle. White marks found in the tissue were attributed to ionising radiation and physical irritation. The results indicate that current methods used for risk assessment, based upon the absorbed dose equivalent limit and estimating the "no-effect dose" are inadequate for radioactive particle exposures. Knowledge is lacking about the ecological implications of radioactive particles released into the environment, for example potential

  13. Real-Time Flood Forecasting System Using Channel Flow Routing Model with Updating by Particle Filter

    NASA Astrophysics Data System (ADS)

    Kudo, R.; Chikamori, H.; Nagai, A.

    2008-12-01

    A real-time flood forecasting system using channel flow routing model was developed for runoff forecasting at water gauged and ungaged points along river channels. The system is based on a flood runoff model composed of upstream part models, tributary part models and downstream part models. The upstream part models and tributary part models are lumped rainfall-runoff models, and the downstream part models consist of a lumped rainfall-runoff model for hillslopes adjacent to a river channel and a kinematic flow routing model for a river channel. The flow forecast of this model is updated by Particle filtering of the downstream part model as well as by the extended Kalman filtering of the upstream part model and the tributary part models. The Particle filtering is a simple and powerful updating algorithm for non-linear and non-gaussian system, so that it can be easily applied to the downstream part model without complicated linearization. The presented flood runoff model has an advantage in simlecity of updating procedure to the grid-based distributed models, which is because of less number of state variables. This system was applied to the Gono-kawa River Basin in Japan, and flood forecasting accuracy of the system with both Particle filtering and extended Kalman filtering and that of the system with only extended Kalman filtering were compared. In this study, water gauging stations in the objective basin were divided into two types of stations, that is, reference stations and verification stations. Reference stations ware regarded as ordinary water gauging stations and observed data at these stations are used for calibration and updating of the model. Verification stations ware considered as ungaged or arbitrary points and observed data at these stations are used not for calibration nor updating but for only evaluation of forecasting accuracy. The result confirms that Particle filtering of the downstream part model improves forecasting accuracy of runoff at

  14. Design and Specification of Optical Bandpass Filters for Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS)

    NASA Technical Reports Server (NTRS)

    Leviton, Douglas B.; Tsevetanov, Zlatan; Woodruff, Bob; Mooney, Thomas A.

    1998-01-01

    Advanced optical bandpass filters for the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) have been developed on a filter-by-filter basis through detailed studies which take into account the instrument's science goals, available optical filter fabrication technology, and developments in ACS's charge-coupled-device (CCD) detector technology. These filters include a subset of filters for the Sloan Digital Sky Survey (SDSS) which are optimized for astronomical photometry using today's charge-coupled-devices (CCD's). In order for ACS to be truly advanced, these filters must push the state-of-the-art in performance in a number of key areas at the same time. Important requirements for these filters include outstanding transmitted wavefront, high transmittance, uniform transmittance across each filter, spectrally structure-free bandpasses, exceptionally high out of band rejection, a high degree of parfocality, and immunity to environmental degradation. These constitute a very stringent set of requirements indeed, especially for filters which are up to 90 mm in diameter. The highly successful paradigm in which final specifications for flight filters were derived through interaction amongst the ACS Science Team, the instrument designer, the lead optical engineer, and the filter designer and vendor is described. Examples of iterative design trade studies carried out in the context of science needs and budgetary and schedule constraints are presented. An overview of the final design specifications for the ACS bandpass and ramp filters is also presented.

  15. Evaluation of Particle Counter Technology for Detection of Fuel Contamination Detection Utilizing Advanced Aviation Forward Area Refueling System

    DTIC Science & Technology

    2014-01-24

    replacement of water bottom removal.  Recirculation – Air was purged from the filter separator vessel and fuel was again pumped from the tank , through...8, Automatic Particle Counter, cleanliness, free water , Diesel 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT none 18. NUMBER OF...Advanced Aviation Forward Area Refueling System Joel Schmitigal U S Army Tank Automotive Research DISTRIBUTION STATEMENT A. Approved for public release

  16. Particle Filters for Real-Time Fault Detection in Planetary Rovers

    NASA Technical Reports Server (NTRS)

    Dearden, Richard; Clancy, Dan; Koga, Dennis (Technical Monitor)

    2001-01-01

    Planetary rovers provide a considerable challenge for robotic systems in that they must operate for long periods autonomously, or with relatively little intervention. To achieve this, they need to have on-board fault detection and diagnosis capabilities in order to determine the actual state of the vehicle, and decide what actions are safe to perform. Traditional model-based diagnosis techniques are not suitable for rovers due to the tight coupling between the vehicle's performance and its environment. Hybrid diagnosis using particle filters is presented as an alternative, and its strengths and weakeners are examined. We also present some extensions to particle filters that are designed to make them more suitable for use in diagnosis problems.

  17. Unscented particle filtering for estimation of shipboard deformation based on inertial measurement units.

    PubMed

    Wang, Bo; Xiao, Xuan; Xia, Yuanqing; Fu, Mengyin

    2013-11-15

    Shipboard is not an absolute rigid body. Many factors could cause deformations which lead to large errors of mounted devices, especially for the navigation systems. Such errors should be estimated and compensated effectively, or they will severely reduce the navigation accuracy of the ship. In order to estimate the deformation, an unscented particle filter method for estimation of shipboard deformation based on an inertial measurement unit is presented. In this method, a nonlinear shipboard deformation model is built. Simulations demonstrated the accuracy reduction due to deformation. Then an attitude plus angular rate match mode is proposed as a frame to estimate the shipboard deformation using inertial measurement units. In this frame, for the nonlinearity of the system model, an unscented particle filter method is proposed to estimate and compensate the deformation angles. Simulations show that the proposed method gives accurate and rapid deformation estimations, which can increase navigation accuracy after compensation of deformation.

  18. Unscented Particle Filtering for Estimation of Shipboard Deformation Based on Inertial Measurement Units

    PubMed Central

    Wang, Bo; Xiao, Xuan; Xia, Yuanqing; Fu, Mengyin

    2013-01-01

    Shipboard is not an absolute rigid body. Many factors could cause deformations which lead to large errors of mounted devices, especially for the navigation systems. Such errors should be estimated and compensated effectively, or they will severely reduce the navigation accuracy of the ship. In order to estimate the deformation, an unscented particle filter method for estimation of shipboard deformation based on an inertial measurement unit is presented. In this method, a nonlinear shipboard deformation model is built. Simulations demonstrated the accuracy reduction due to deformation. Then an attitude plus angular rate match mode is proposed as a frame to estimate the shipboard deformation using inertial measurement units. In this frame, for the nonlinearity of the system model, an unscented particle filter method is proposed to estimate and compensate the deformation angles. Simulations show that the proposed method gives accurate and rapid deformation estimations, which can increase navigation accuracy after compensation of deformation. PMID:24248280

  19. Particle Filtering with Region-based Matching for Tracking of Partially Occluded and Scaled Targets*

    PubMed Central

    Nakhmani, Arie; Tannenbaum, Allen

    2012-01-01

    Visual tracking of arbitrary targets in clutter is important for a wide range of military and civilian applications. We propose a general framework for the tracking of scaled and partially occluded targets, which do not necessarily have prominent features. The algorithm proposed in the present paper utilizes a modified normalized cross-correlation as the likelihood for a particle filter. The algorithm divides the template, selected by the user in the first video frame, into numerous patches. The matching process of these patches by particle filtering allows one to handle the target’s occlusions and scaling. Experimental results with fixed rectangular templates show that the method is reliable for videos with nonstationary, noisy, and cluttered background, and provides accurate trajectories in cases of target translation, scaling, and occlusion. PMID:22506088

  20. Combining Particle Filters and Consistency-Based Approaches for Monitoring and Diagnosis of Stochastic Hybrid Systems

    NASA Technical Reports Server (NTRS)

    Narasimhan, Sriram; Dearden, Richard; Benazera, Emmanuel

    2004-01-01

    Fault detection and isolation are critical tasks to ensure correct operation of systems. When we consider stochastic hybrid systems, diagnosis algorithms need to track both the discrete mode and the continuous state of the system in the presence of noise. Deterministic techniques like Livingstone cannot deal with the stochasticity in the system and models. Conversely Bayesian belief update techniques such as particle filters may require many computational resources to get a good approximation of the true belief state. In this paper we propose a fault detection and isolation architecture for stochastic hybrid systems that combines look-ahead Rao-Blackwellized Particle Filters (RBPF) with the Livingstone 3 (L3) diagnosis engine. In this approach RBPF is used to track the nominal behavior, a novel n-step prediction scheme is used for fault detection and L3 is used to generate a set of candidates that are consistent with the discrepant observations which then continue to be tracked by the RBPF scheme.

  1. Auxiliary particle filter-model predictive control of the vacuum arc remelting process

    NASA Astrophysics Data System (ADS)

    Lopez, F.; Beaman, J.; Williamson, R.

    2016-07-01

    Solidification control is required for the suppression of segregation defects in vacuum arc remelting of superalloys. In recent years, process controllers for the VAR process have been proposed based on linear models, which are known to be inaccurate in highly-dynamic conditions, e.g. start-up, hot-top and melt rate perturbations. A novel controller is proposed using auxiliary particle filter-model predictive control based on a nonlinear stochastic model. The auxiliary particle filter approximates the probability of the state, which is fed to a model predictive controller that returns an optimal control signal. For simplicity, the estimation and control problems are solved using Sequential Monte Carlo (SMC) methods. The validity of this approach is verified for a 430 mm (17 in) diameter Alloy 718 electrode melted into a 510 mm (20 in) diameter ingot. Simulation shows a more accurate and smoother performance than the one obtained with an earlier version of the controller.

  2. Statistical Orbit Determination using the Particle Filter for Incorporating Non-Gaussian Uncertainties

    NASA Technical Reports Server (NTRS)

    Mashiku, Alinda; Garrison, James L.; Carpenter, J. Russell

    2012-01-01

    The tracking of space objects requires frequent and accurate monitoring for collision avoidance. As even collision events with very low probability are important, accurate prediction of collisions require the representation of the full probability density function (PDF) of the random orbit state. Through representing the full PDF of the orbit state for orbit maintenance and collision avoidance, we can take advantage of the statistical information present in the heavy tailed distributions, more accurately representing the orbit states with low probability. The classical methods of orbit determination (i.e. Kalman Filter and its derivatives) provide state estimates based on only the second moments of the state and measurement errors that are captured by assuming a Gaussian distribution. Although the measurement errors can be accurately assumed to have a Gaussian distribution, errors with a non-Gaussian distribution could arise during propagation between observations. Moreover, unmodeled dynamics in the orbit model could introduce non-Gaussian errors into the process noise. A Particle Filter (PF) is proposed as a nonlinear filtering technique that is capable of propagating and estimating a more complete representation of the state distribution as an accurate approximation of a full PDF. The PF uses Monte Carlo runs to generate particles that approximate the full PDF representation. The PF is applied in the estimation and propagation of a highly eccentric orbit and the results are compared to the Extended Kalman Filter and Splitting Gaussian Mixture algorithms to demonstrate its proficiency.

  3. Segmentation of nerve bundles and ganglia in spine MRI using particle filters.

    PubMed

    Dalca, Adrian; Danagoulian, Giovanna; Kikinis, Ron; Schmidt, Ehud; Golland, Polina

    2011-01-01

    Automatic segmentation of spinal nerve bundles that originate within the dural sac and exit the spinal canal is important for diagnosis and surgical planning. The variability in intensity, contrast, shape and direction of nerves seen in high resolution myelographic MR images makes segmentation a challenging task. In this paper, we present an automatic tracking method for nerve segmentation based on particle filters. We develop a novel approach to particle representation and dynamics, based on Bézier splines. Moreover, we introduce a robust image likelihood model that enables delineation of nerve bundles and ganglia from the surrounding anatomical structures. We demonstrate accurate and fast nerve tracking and compare it to expert manual segmentation.

  4. 3D Air Filtration Modeling for Nanofiber Based Filters in the Ultrafine Particle Size Range

    NASA Astrophysics Data System (ADS)

    Sambaer, Wannes; Zatloukal, Martin; Kimmer, Dusan

    2011-07-01

    In this work, novel 3D filtration model for nanofiber based filters has been proposed and tested. For the model validation purposes, filtration efficiency characteristics of two different polyurethane nanofiber based structures (prepared by the electrospinning process) were determined experimentally in the ultrafine particle size range (20-400 nm). It has been found that the proposed model is able to reasonably predict the measured filtration efficiency curves for both tested samples.

  5. Fabrication of advanced particles and particle-based materials assisted by droplet-based microfluidics.

    PubMed

    Wang, Jing-Tao; Wang, Juan; Han, Jun-Jie

    2011-07-04

    Recent advances in the fabrication of complex particles and particle-based materials assisted by droplet-based microfluidics are reviewed. Monodisperse particles with expected internal structures, morphologies, and sizes in the range of nanometers to hundreds of micrometers have received a good deal of attention in recent years. Due to the capability of generating monodisperse emulsions and of executing precise control and operations on the suspended droplets inside the microchannels, droplet-based microfluidic devices have become powerful tools for fabricating complex particles with desired properties. Emulsions and multiple-emulsions generated in the microfluidic devices can be composed of a variety of materials including aqueous solutions, gels, polymers and solutions containing functional nanoparticles. They are ideal microreactors or fine templates for synthesizing advanced particles, such as polymer particles, microcapsules, nanocrystals, and photonic crystal clusters or beads by further chemical or physical operations. These particles are promising materials that may be applicable for many fields, such as photonic materials, drug delivery systems, and bio-analysis. From simple to complex, from spherical to nonspherical, from polymerization and reaction crystallization to self-assembly, this review aims to help readers be aware of the many aspects of this field.

  6. Comparison of EKF, pseudomeasurement, and particle filters for a bearing-only target tracking problem

    NASA Astrophysics Data System (ADS)

    Lin, Xiangdong; Kirubarajan, Thiagalingam; Bar-Shalom, Yaakov; Maskell, Simon

    2002-08-01

    In this paper we consider a nonlinear bearing-only target tracking problem using three different methods and compare their performances. The study is motivated by a ground surveillance problem where a target is tracked from an airborne sensor at an approximately known altitude using depression angle observations. Two nonlinear suboptimal estimators, namely, the extended Kalman Filter (EKF) and the pseudomeasurement tracking filter are applied in a 2-D bearing-only tracking scenario. The EKF is based on the linearization of the nonlinearities in the dynamic and/or the measurement equations. The pseudomeasurement tracking filter manipulates the original nonlinear measurement algebraically to obtain the linear-like structures measurement. Finally, the particle filter, which is a Monte Carlo integration based optimal nonlinear filter and has been presented in the literature as a better alternative to linearization via EKF, is used on the same problem. The performances of these three different techniques in terms of accuracy and computational load are presented in this paper. The results demonstrate the limitations of these algorithms on this deceptively simple tracking problem.

  7. Particle properties in granular activated carbon filter during drinking water treatment.

    PubMed

    Lin, Tao; Chen, Wei; Wang, Leilei

    2010-01-01

    The elemental composition and bacteria attached in particles were investigated during granular activated carbon (GAC) filtration. The experimental results showed that trapped influent particles could form new, larger particles on GAC surface. The sloughing of individuals off GAC surface caused an increase in effluent particles in the size range from 5 to 25 tm. The selectivity for element removal in GAC filters caused an increasing proportion of metallic elements in the effluent particles. The distribution of molar ratio indicated a complicated composition for large particles, involving organic and inorganic substances. The organic proportion accounted for 40% of total carbon attached to the particles. Compared with dissolved carbon, there was potential for the formation of trihalomethanes by organic carbon attached to particles, especially for those with size larger than 10 im. The pure carbon energy spectrum was found only in the GAC effluent and the size distribution of carbon fines was mainly above 10 microm. The larger carbon fines provided more space for bacterial colonization and stronger protection for attached bacteria against disinfection. The residual attached bacteria after chorine disinfection was increased to 10(2)-l0(3) CFU/mL within 24 hours at 25 degrees C.

  8. Perihelion advance of a test particle in the Kerr field.

    NASA Astrophysics Data System (ADS)

    Haque, Enamul

    2017-01-01

    Here I represent a Perihelion advance of a test particle in the Kerr field. I assume that the spin of the central body to be very small and planar motion occurs only in the equatorial plane. I find some physical picture which is different from the case of Schwarzschild field and can recover the picture for Schwarzschild field. We use perturbation method to solve the equation of motion.

  9. Robust Dead Reckoning System for Mobile Robots Based on Particle Filter and Raw Range Scan

    PubMed Central

    Duan, Zhuohua; Cai, Zixing; Min, Huaqing

    2014-01-01

    Robust dead reckoning is a complicated problem for wheeled mobile robots (WMRs), where the robots are faulty, such as the sticking of sensors or the slippage of wheels, for the discrete fault models and the continuous states have to be estimated simultaneously to reach a reliable fault diagnosis and accurate dead reckoning. Particle filters are one of the most promising approaches to handle hybrid system estimation problems, and they have also been widely used in many WMRs applications, such as pose tracking, SLAM, video tracking, fault identification, etc. In this paper, the readings of a laser range finder, which may be also interfered with by noises, are used to reach accurate dead reckoning. The main contribution is that a systematic method to implement fault diagnosis and dead reckoning in a particle filter framework concurrently is proposed. Firstly, the perception model of a laser range finder is given, where the raw scan may be faulty. Secondly, the kinematics of the normal model and different fault models for WMRs are given. Thirdly, the particle filter for fault diagnosis and dead reckoning is discussed. At last, experiments and analyses are reported to show the accuracy and efficiency of the presented method. PMID:25192318

  10. Electrostatic Introduction Theory Based Spatial Filtering Method for Solid Particle Velocity Measurement

    NASA Astrophysics Data System (ADS)

    Xu, Chuanlong; Tang, Guanghua; Zhou, Bin; Yang, Daoye; Zhang, Jianyong; Wang, Shimin

    2007-06-01

    Electrostatic induction theory based spatial filtering method for particle velocity measurement has the advantages of the simplicity of measurement system and of the convenience of data processing. In this paper, the relationship between solid particle velocity and the power spectrum of the output signal of the electrostatic senor was derived theoretically. And the effects of the length of the electrode, the thickness of the dielectric pipe and its length on the spatial filtering characteristics of the electrostatic sensor were investigated numerically using finite element method. Additionally, as for the roughness and the difficult determination of the peak frequency fmax of the power spectrum characteristics curve of the output signal, a wavelet analysis based filtering method was adopted to smooth the curve, which can determine peak frequency fmax accurately. Finally, the velocity measurement method was applied in a dense phase pneumatic conveying system under high pressure, and the experimental results show that the system repeatability is within ±4% over the gas superficial velocity range of 8.63-18.62 m/s for particle concentration range 0.067-0.130 m3/m3.

  11. Fitting complex population models by combining particle filters with Markov chain Monte Carlo.

    PubMed

    Knape, Jonas; de Valpine, Perry

    2012-02-01

    We show how a recent framework combining Markov chain Monte Carlo (MCMC) with particle filters (PFMCMC) may be used to estimate population state-space models. With the purpose of utilizing the strengths of each method, PFMCMC explores hidden states by particle filters, while process and observation parameters are estimated using an MCMC algorithm. PFMCMC is exemplified by analyzing time series data on a red kangaroo (Macropus rufus) population in New South Wales, Australia, using MCMC over model parameters based on an adaptive Metropolis-Hastings algorithm. We fit three population models to these data; a density-dependent logistic diffusion model with environmental variance, an unregulated stochastic exponential growth model, and a random-walk model. Bayes factors and posterior model probabilities show that there is little support for density dependence and that the random-walk model is the most parsimonious model. The particle filter Metropolis-Hastings algorithm is a brute-force method that may be used to fit a range of complex population models. Implementation is straightforward and less involved than standard MCMC for many models, and marginal densities for model selection can be obtained with little additional effort. The cost is mainly computational, resulting in long running times that may be improved by parallelizing the algorithm.

  12. Sound speed estimation and source localization with linearization and particle filtering.

    PubMed

    Lin, Tao; Michalopoulou, Zoi-Heleni

    2014-03-01

    A method is developed for the estimation of source location and sound speed in the water column relying on linearization. The Jacobian matrix, necessary for the proposed linearization approach, includes derivatives with respect to empirical orthogonal function coefficients instead of sound speed directly. First, the inversion technique is tested on synthetic arrival times, using Gaussian distributions for the errors in the considered arrival times. The approach is efficient, requiring a few iterations, and produces accurate results. Probability densities of the estimates are calculated for different levels of noise in the arrival times. Subsequently, particle filtering is employed for the estimation of arrival times from signals recorded during the Shallow Water 06 experiment. It has been shown in the past that particle filtering can be employed for the successful estimation of multipath arrival times from short-range data and, consequently, in geometry, bathymetry, and sound speed inversion. Here probability density functions of arrival times computed via particle filtering are propagated backward through the proposed inversion process. Inversion estimates are consistent with values reported in the literature for the same quantities. Last it is shown that results are consistent with estimates resulting from fast simulated annealing applied to the same data.

  13. Thermo-mechanical analysis of a user filter assembly for undulator/wiggler operations at the Advanced Photon Source

    SciTech Connect

    Nian, H.L.T.; Kuzay, T.M.; Collins, J.; Shu, D.; Benson, C.; Dejus, R.

    1996-12-31

    This paper reports a thermo-mechanical study of a beamline filter (user filter) for undulator/wiggler operations. It is deployed in conjunction with the current commissioning window assembly on the APS insertion device (ID) front ends. The beamline filter at the Advanced Photon Source (APS) will eventually be used in windowless operations also. Hence survival and reasonable life expectancy of the filters under intense insertion device (ID) heat flu are crucial to the beamline operations. To accommodate various user requirements, the filter is configured to be a multi-choice type and smart to allow only those filter combinations that will be safe to operate with a given ring current and beamline insertion device gap. However, this paper addresses only the thermo-mechanical analysis of individual filter integrity and safety in all combinations possible. The current filter design is configured to have four filter frames in a cascade with each frame holding five filters. This allows a potential 625 total filter combinations. Thermal analysis for all of these combinations becomes a mammoth task considering the desired choices for filter materials (pyrolitic graphite and metallic filters), filter thicknesses, undulator gaps, and the beam currents. The paper addresses how this difficult task has been reduced to a reasonable effort and computational level. Results from thermo-mechanical analyses of the filter combinations are presented both in tabular and graphical format.

  14. Filter feeders and plankton increase particle encounter rates through flow regime control

    PubMed Central

    Humphries, Stuart

    2009-01-01

    Collisions between particles or between particles and other objects are fundamental to many processes that we take for granted. They drive the functioning of aquatic ecosystems, the onset of rain and snow precipitation, and the manufacture of pharmaceuticals, powders and crystals. Here, I show that the traditional assumption that viscosity dominates these situations leads to consistent and large-scale underestimation of encounter rates between particles and of deposition rates on surfaces. Numerical simulations reveal that the encounter rate is Reynolds number dependent and that encounter efficiencies are consistent with the sparse experimental data. This extension of aerosol theory has great implications for understanding of selection pressure on the physiology and ecology of organisms, for example filter feeders able to gather food at rates up to 5 times higher than expected. I provide evidence that filter feeders have been strongly selected to take advantage of this flow regime and show that both the predicted peak concentration and the steady-state concentrations of plankton during blooms are ≈33% of that predicted by the current models of particle encounter. Many ecological and industrial processes may be operating at substantially greater rates than currently assumed. PMID:19416879

  15. Joint Target Detection and Tracking Filter for Chilbolton Advanced Meteorological Radar Data Processing

    NASA Astrophysics Data System (ADS)

    Pak, A.; Correa, J.; Adams, M.; Clark, D.; Delande, E.; Houssineau, J.; Franco, J.; Frueh, C.

    2016-09-01

    Recently, the growing number of inactive Resident Space Objects (RSOs), or space debris, has provoked increased interest in the field of Space Situational Awareness (SSA) and various investigations of new methods for orbital object tracking. In comparison with conventional tracking scenarios, state estimation of an orbiting object entails additional challenges, such as orbit determination and orbital state and covariance propagation in the presence of highly nonlinear system dynamics. The sensors which are available for detecting and tracking space debris are prone to multiple clutter measurements. Added to this problem, is the fact that it is unknown whether or not a space debris type target is present within such sensor measurements. Under these circumstances, traditional single-target filtering solutions such as Kalman Filters fail to produce useful trajectory estimates. The recent Random Finite Set (RFS) based Finite Set Statistical (FISST) framework has yielded filters which are more appropriate for such situations. The RFS based Joint Target Detection and Tracking (JoTT) filter, also known as the Bernoulli filter, is a single target, multiple measurements filter capable of dealing with cluttered and time-varying backgrounds as well as modeling target appearance and disappearance in the scene. Therefore, this paper presents the application of the Gaussian mixture-based JoTT filter for processing measurements from Chilbolton Advanced Meteorological Radar (CAMRa) which contain both defunct and operational satellites. The CAMRa is a fully-steerable radar located in southern England, which was recently modified to be used as a tracking asset in the European Space Agency SSA program. The experiments conducted show promising results regarding the capability of such filters in processing cluttered radar data. The work carried out in this paper was funded by the USAF Grant No. FA9550-15-1-0069, Chilean Conicyt - Fondecyt grant number 1150930, EU Erasmus Mundus MSc

  16. Characterization of the interactions within fine particle mixtures in highly concentrated suspensions for advanced particle processing.

    PubMed

    Otsuki, Akira; Bryant, Gary

    2015-12-01

    This paper aims to summarize recent investigations into the dispersion of fine particles, and the characterization of their interactions, in concentrated suspensions. This summary will provide a better understanding of the current status of this research, and will provide useful feedback for advanced particle processing. Such processes include the fabrication of functional nanostructures and the sustainable beneficiation of complex ores. For example, there has been increasing demand for complex ore utilization due to the noticeable decrease in the accessibility of high grade and easily extractable ores. In order to maintain the sustainable use of mineral resources, the effective beneficiation of complex ores is urgently required. It can be successfully achieved only with selective particle/mineral dispersion/liberation and the assistance of mineralogical and particle characterization.

  17. Effects of Particle Filters and Accelerated Engine Replacement on Heavy-Duty Diesel Vehicle Emissions of Black Carbon, Nitrogen Oxides, and Ultrafine Particles

    NASA Astrophysics Data System (ADS)

    Kirchstetter, T.; Preble, C.; Dallmann, T. R.; DeMartini, S. J.; Tang, N. W.; Kreisberg, N. M.; Hering, S. V.; Harley, R. A.

    2013-12-01

    Diesel particle filters have become widely used in the United States since the introduction in 2007 of a more stringent exhaust particulate matter emission standard for new heavy-duty diesel vehicle engines. California has instituted additional regulations requiring retrofit or replacement of older in-use engines to accelerate emission reductions and air quality improvements. This presentation summarizes pollutant emission changes measured over several field campaigns at the Port of Oakland in the San Francisco Bay Area associated with diesel particulate filter use and accelerated modernization of the heavy-duty truck fleet. Pollutants in the exhaust plumes of hundreds of heavy-duty trucks en route to the Port were measured in 2009, 2010, 2011, and 2013. Ultrafine particle number, black carbon (BC), nitrogen oxides (NOx), and nitrogen dioxide (NO2) concentrations were measured at a frequency ≤ 1 Hz and normalized to measured carbon dioxide concentrations to quantify fuel-based emission factors (grams of pollutant emitted per kilogram of diesel consumed). The size distribution of particles in truck exhaust plumes was also measured at 1 Hz. In the two most recent campaigns, emissions were linked on a truck-by-truck basis to installed emission control equipment via the matching of transcribed license plates to a Port truck database. Accelerated replacement of older engines with newer engines and retrofit of trucks with diesel particle filters reduced fleet-average emissions of BC and NOx. Preliminary results from the two most recent field campaigns indicate that trucks without diesel particle filters emit 4 times more BC than filter-equipped trucks. Diesel particle filters increase emissions of NO2, however, and filter-equipped trucks have NO2/NOx ratios that are 4 to 7 times greater than trucks without filters. Preliminary findings related to particle size distribution indicate that (a) most trucks emitted particles characterized by a single mode of approximately

  18. Cascaded Kalman and particle filters for photogrammetry based gyroscope drift and robot attitude estimation.

    PubMed

    Sadaghzadeh N, Nargess; Poshtan, Javad; Wagner, Achim; Nordheimer, Eugen; Badreddin, Essameddin

    2014-03-01

    Based on a cascaded Kalman-Particle Filtering, gyroscope drift and robot attitude estimation method is proposed in this paper. Due to noisy and erroneous measurements of MEMS gyroscope, it is combined with Photogrammetry based vision navigation scenario. Quaternions kinematics and robot angular velocity dynamics with augmented drift dynamics of gyroscope are employed as system state space model. Nonlinear attitude kinematics, drift and robot angular movement dynamics each in 3 dimensions result in a nonlinear high dimensional system. To reduce the complexity, we propose a decomposition of system to cascaded subsystems and then design separate cascaded observers. This design leads to an easier tuning and more precise debugging from the perspective of programming and such a setting is well suited for a cooperative modular system with noticeably reduced computation time. Kalman Filtering (KF) is employed for the linear and Gaussian subsystem consisting of angular velocity and drift dynamics together with gyroscope measurement. The estimated angular velocity is utilized as input of the second Particle Filtering (PF) based observer in two scenarios of stochastic and deterministic inputs. Simulation results are provided to show the efficiency of the proposed method. Moreover, the experimental results based on data from a 3D MEMS IMU and a 3D camera system are used to demonstrate the efficiency of the method.

  19. A particle filter to reconstruct a free-surface flow from a depth camera

    NASA Astrophysics Data System (ADS)

    Combés, Benoit; Heitz, Dominique; Guibert, Anthony; Mémin, Etienne

    2015-10-01

    We investigate the combined use of a kinect depth sensor and of a stochastic data assimilation (DA) method to recover free-surface flows. More specifically, we use a weighted ensemble Kalman filter method to reconstruct the complete state of free-surface flows from a sequence of depth images only. This particle filter accounts for model and observations errors. This DA scheme is enhanced with the use of two observations instead of one classically. We evaluate the developed approach on two numerical test cases: a collapse of a water column as a toy-example and a flow in an suddenly expanding flume as a more realistic flow. The robustness of the method to depth data errors and also to initial and inflow conditions is considered. We illustrate the interest of using two observations instead of one observation into the correction step, especially for unknown inflow boundary conditions. Then, the performance of the Kinect sensor in capturing the temporal sequences of depth observations is investigated. Finally, the efficiency of the algorithm is qualified for a wave in a real rectangular flat bottomed tank. It is shown that for basic initial conditions, the particle filter rapidly and remarkably reconstructs the velocity and height of the free surface flow based on noisy measurements of the elevation alone.

  20. Advanced filter banks and time interleaving for analog and digital conversion

    NASA Astrophysics Data System (ADS)

    Velazquez, Scott R.

    1999-10-01

    This paper presents a comparison of Advanced Filter Banks (AFB) and Time-Interleaving for high-speed, high-resolution conversion between analog and digital signals using a parallel array of converters. The AFB is an unconventional class of filter bank that employs both analog and digital signal processing. The AFB improves the speed and resolution of the conversion compared to the standard Time-Interleaved array conversion technique. Gain and phase mismatch errors are analyzed for both the AFB and Time-Interleaving architectures. The filters in the AFB isolate the converters in the array from each other and attenuate the effects of mismatches. In four-channel example systems analyzed in this paper, gain and phase errors are attenuated by 21 dB more in the AFB (with 30 dB stopband attenuation) than in the Time- Interleaved system. The AFB is capable of analog-to-digital conversion with 14-bit resolution and 400 MHz sample rate.

  1. An advanced threshold-extension tracking filter for satellite video reception

    NASA Astrophysics Data System (ADS)

    Rogers, W. M.

    Developments related to frequency-modulated television transmission via satellite repeaters have hade large commercial applications in connection with earth terminals for satellite TV reception. Difficulties concerning the assurance of a satisfactory quality of video and audio reception are related to the threshold phenomenon, which exists in any realizable FM receiver. Its onset cannot be eliminated, but it can be delayed with a more sophisticated 'threshold-extension demodulator' (TED). For given performance criteria, the best threshold extension available usually results in the lowest overall earth terminal cost. Suitable threshold-extension techniques are discussed, taking into account the employment of open-loop and closed-loop tracking filters. A description is provided of a TED which represents a new closed-loop tracking filter invention. Attention is given to advanced tracking filter implementation, performance results, and projected and potential future applications.

  2. Particle filtering for arrival time tracking in space and source localization.

    PubMed

    Michalopoulou, Zoi-Heleni; Jain, Rashi

    2012-11-01

    Locating and tracking a source in an ocean environment and estimating environmental parameters of a sound propagation medium are critical tasks in ocean acoustics. Many approaches for both are based on full field calculations which are computationally intensive and sensitive to assumptions on the structure of the environment. Alternative methods that use only select features of the acoustic field for localization and environmental parameter estimation have been proposed. The focus of this paper is the development of a method that extracts arrival times and amplitudes of distinct paths from measured acoustic time-series using sequential Bayesian filtering, namely, particle filtering. These quantities, along with complete posterior probability density functions, also extracted by filtering, are employed in source localization and bathymetry estimation. Aspects of the filtering methodology are presented and studied in terms of their impact on the uncertainty in the arrival time estimates. Using the posterior probability densities of arrival times, source localization and water depth estimation are performed for the Haro Strait Primer experiment; the results are compared to those of conventional methods. The comparison demonstrates a significant advantage in the proposed approach.

  3. Absorption/transmission measurements of PSAP particle-laden filters from the Biomass Burning Observation Project (BBOP) field campaign

    SciTech Connect

    Presser, Cary; Nazarian, Ashot; Conny, Joseph M.; Chand, Duli; Sedlacek, Arthur; Hubbe, John M.

    2016-12-02

    Absorptivity measurements with a laser-heating approach, referred to as the laser-driven thermal reactor (LDTR), were carried out in the infrared and applied at ambient (laboratory) nonreacting conditions to particle-laden filters from a three-wavelength (visible) particle/soot absorption photometer (PSAP). Here, the particles were obtained during the Biomass Burning Observation Project (BBOP) field campaign. The focus of this study was to determine the particle absorption coefficient from field-campaign filter samples using the LDTR approach, and compare results with other commercially available instrumentation (in this case with the PSAP, which has been compared with numerous other optical techniques).

  4. Using particle filter to track horizontal variations of atmospheric duct structure from radar sea clutter

    NASA Astrophysics Data System (ADS)

    Zhao, X. F.; Huang, S. X.; Wang, D. X.

    2012-11-01

    This paper addresses the problem of estimating range-varying parameters of the height-dependent refractivity over the sea surface from radar sea clutter. In the forward simulation, the split-step Fourier parabolic equation (PE) is used to compute the radar clutter power in the complex refractive environments. Making use of the inherent Markovian structure of the split-step Fourier PE solution, the refractivity from clutter (RFC) problem is formulated within a nonlinear recursive Bayesian state estimation framework. Particle filter (PF), which is a technique for implementing a recursive Bayesian filter by Monte Carlo simulations, is used to track range-varying characteristics of the refractivity profiles. Basic ideas of employing PF to solve RFC problem are introduced. Both simulation and real data results are presented to confirm the feasibility of PF-RFC performances.

  5. Using particle filter to track horizontal variations of atmospheric duct structure from radar sea clutter

    NASA Astrophysics Data System (ADS)

    Zhao, X. F.; Huang, S. X.

    2012-08-01

    This paper addresses the problem of estimating range-varying parameters of the height-dependent refractivity over the sea surface from radar sea clutter. In the forward simulation, the split-step Fourier parabolic equation (PE) is used to compute the radar clutter power in the complex refractive environments. Making use of the inherent Markovian structure of the split-step Fourier PE solution, the refractivity from clutter (RFC) problem is formulated within a nonlinear recursive Bayesian state estimation framework. Particle filter (PF) that is a technique for implementing a recursive Bayesian filter by Monte Carlo simulations is used to track range-varying characteristics of the refractivity profiles. Basic ideas of employing PF to solve RFC problem are introduced. Both simulation and real data results are presented to check up the feasibility of PF-RFC performances.

  6. Particle capture processes and evaporation on a microscopic scale in wet filters.

    PubMed

    Mullins, Benjamin J; Braddock, Roger D; Agranovski, Igor E

    2004-11-01

    This paper details results of an experimental study of the capture of solid and liquid aerosols on fibrous filters wetted with water. A microscopic cell containing a single fibre (made from a variety of materials) was observed via a microscope, with a high speed CCD camera used to dynamically image the interactions between liquid droplets, zeolite and PSL particles and fibres. Variable quantities of liquid irrigation were used, and the possibility for subsequent fibre regeneration after clogging or drying was also studied. It was found that drainage of the wetting liquid (water) from the fibres occurred, even at very low irrigation rates when the droplet consisted almost completely of captured particles. It was also found that the fibre was rapidly loaded with captured particles when the irrigation was not supplied. However, almost complete regeneration (removal of the collected cake) by the liquid droplets occurred shortly after recommencement of the water supply. The study also examined the capture of oily liquid aerosols on fibres wetted with water. A predominance of the barrel shaped droplet on the fibre was observed, with oil droplets displacing water droplets (if the oil and fibre combination created a barrel shaped droplet), creating various compound droplets of oil and water not previously reported in literature. This preferential droplet shape implies that whatever the initial substance wetting a filter, a substance with a greater preferential adherence to the fibre will displace the former one.

  7. Representation of Probability Density Functions from Orbit Determination using the Particle Filter

    NASA Technical Reports Server (NTRS)

    Mashiku, Alinda K.; Garrison, James; Carpenter, J. Russell

    2012-01-01

    Statistical orbit determination enables us to obtain estimates of the state and the statistical information of its region of uncertainty. In order to obtain an accurate representation of the probability density function (PDF) that incorporates higher order statistical information, we propose the use of nonlinear estimation methods such as the Particle Filter. The Particle Filter (PF) is capable of providing a PDF representation of the state estimates whose accuracy is dependent on the number of particles or samples used. For this method to be applicable to real case scenarios, we need a way of accurately representing the PDF in a compressed manner with little information loss. Hence we propose using the Independent Component Analysis (ICA) as a non-Gaussian dimensional reduction method that is capable of maintaining higher order statistical information obtained using the PF. Methods such as the Principal Component Analysis (PCA) are based on utilizing up to second order statistics, hence will not suffice in maintaining maximum information content. Both the PCA and the ICA are applied to two scenarios that involve a highly eccentric orbit with a lower apriori uncertainty covariance and a less eccentric orbit with a higher a priori uncertainty covariance, to illustrate the capability of the ICA in relation to the PCA.

  8. A localized particle filter for data assimilation in high-dimensional geophysical models.

    NASA Astrophysics Data System (ADS)

    Poterjoy, Jonathan; Anderon, Jeffrey

    2016-04-01

    This talk introduces an ensemble data assimilation approach based on the particle filter (PF) that has potential for nonlinear/non-Gaussian applications in geoscience. PFs make no assumptions regarding prior and posterior error distributions, allowing them to perform well for most applications provided with a sufficiently large number of particles. The proposed method is similar to the PF in that ensemble realizations of the model state are weighted based on the likelihood of observations to approximate posterior probabilities of the system state. The new approach, denoted the local PF, reduces the influence of distant observations on the weight calculations via a localization function. Unlike standard PFs, the local PF provides accurate results using ensemble sizes small enough to be affordable for large models. Comparisons of the local PF and ensemble Kalman filters using a simplified atmospheric general circulation model (with 25 particles) demonstrate that the new method is a viable data assimilation technique for large geophysical systems. The local PF also shows substantial benefits over the EnKF when observation networks consist of measurements that relate nonlinearly to the model state - analogous to remotely sensed data used frequently in atmospheric analyses.

  9. Alignment of 3-D optical coherence tomography scans to correct eye movement using a particle filtering.

    PubMed

    Xu, Juan; Ishikawa, Hiroshi; Wollstein, Gadi; Kagemann, Larry; Schuman, Joel S

    2012-07-01

    Eye movement artifacts occurring during 3-D optical coherence tomography (OCT) scanning is a well-recognized problem that may adversely affect image analysis and interpretation. A particle filtering algorithm is presented in this paper to correct motion in a 3-D dataset by considering eye movement as a target tracking problem in a dynamic system. The proposed particle filtering algorithm is an independent 3-D alignment approach, which does not rely on any reference image. 3-D OCT data is considered as a dynamic system, while the location of each A-scan is represented by the state space. A particle set is used to approximate the probability density of the state in the dynamic system. The state of the system is updated frame by frame to detect A-scan movement. The proposed method was applied on both simulated data for objective evaluation and experimental data for subjective evaluation. The sensitivity and specificity of the x-movement detection were 98.85% and 99.43%, respectively, in the simulated data. For the experimental data (74 3-D OCT images), all the images were improved after z-alignment, while 81.1% images were improved after x-alignment. The proposed algorithm is an efficient way to align 3-D OCT volume data and correct the eye movement without using references.

  10. Modified Particle Filtering Algorithm for Single Acoustic Vector Sensor DOA Tracking

    PubMed Central

    Li, Xinbo; Sun, Haixin; Jiang, Liangxu; Shi, Yaowu; Wu, Yue

    2015-01-01

    The conventional direction of arrival (DOA) estimation algorithm with static sources assumption usually estimates the source angles of two adjacent moments independently and the correlation of the moments is not considered. In this article, we focus on the DOA estimation of moving sources and a modified particle filtering (MPF) algorithm is proposed with state space model of single acoustic vector sensor. Although the particle filtering (PF) algorithm has been introduced for acoustic vector sensor applications, it is not suitable for the case that one dimension angle of source is estimated with large deviation, the two dimension angles (pitch angle and azimuth angle) cannot be simultaneously employed to update the state through resampling processing of PF algorithm. To solve the problems mentioned above, the MPF algorithm is proposed in which the state estimation of previous moment is introduced to the particle sampling of present moment to improve the importance function. Moreover, the independent relationship of pitch angle and azimuth angle is considered and the two dimension angles are sampled and evaluated, respectively. Then, the MUSIC spectrum function is used as the “likehood” function of the MPF algorithm, and the modified PF-MUSIC (MPF-MUSIC) algorithm is proposed to improve the root mean square error (RMSE) and the probability of convergence. The theoretical analysis and the simulation results validate the effectiveness and feasibility of the two proposed algorithms. PMID:26501280

  11. Dynamic omni-directional vision localization using a beacon tracker based on particle filter

    NASA Astrophysics Data System (ADS)

    Cao, Zuoliang; Liu, Shiyu

    2007-09-01

    Omni-directional vision navigation for AGVs appears definite significant since its advantage of panoramic sight with a single compact visual scene. This unique guidance technique involves target recognition, vision tracking, object positioning, path programming. An algorithm for omni-vision based global localization which utilizes two overhead features as beacon pattern is proposed in this paper. An approach for geometric restoration of omni-vision images has to be considered since an inherent distortion exists. The mapping between image coordinates and physical space parameters of the targets can be obtained by means of the imaging principle on the fisheye lens. The localization of the robot can be achieved by geometric computation. Dynamic localization employs a beacon tracker to follow the landmarks in real time during the arbitrary movement of the vehicle. The coordinate transformation is devised for path programming based on time sequence images analysis. The beacon recognition and tracking are a key procedure for an omni-vision guided mobile unit. The conventional image processing such as shape decomposition, description, matching and other usually employed technique are not directly applicable in omni-vision. Particle filter (PF) has been shown to be successful for several nonlinear estimation problems. A beacon tracker based on Particle Filter which offers a probabilistic framework for dynamic state estimation in visual tracking has been developed. We independently use two Particle Filters to track double landmarks but a composite algorithm on multiple objects tracking conducts for vehicle localization. We have implemented the tracking and localization system and demonstrated the relevant of the algorithm.

  12. Enhancement of microfluidic particle separation using cross-flow filters with hydrodynamic focusing

    PubMed Central

    Chiu, Yun-Yen; Huang, Chen-Kang

    2016-01-01

    A microfluidic chip is proposed to separate microparticles using cross-flow filtration enhanced with hydrodynamic focusing. By exploiting a buffer flow from the side, the microparticles in the sample flow are pushed on one side of the microchannels, lining up to pass through the filters. Meanwhile a larger pressure gradient in the filters is obtained to enhance separation efficiency. Compared with the traditional cross-flow filtration, our proposed mechanism has the buffer flow to create a moving virtual boundary for the sample flow to actively push all the particles to reach the filters for separation. It further allows higher flow rates. The device only requires soft lithograph fabrication to create microchannels and a novel pressurized bonding technique to make high-aspect-ratio filtration structures. A mixture of polystyrene microparticles with 2.7 μm and 10.6 μm diameters are successfully separated. 96.2 ± 2.8% of the large particle are recovered with a purity of 97.9 ± 0.5%, while 97.5 ± 0.4% of the small particle are depleted with a purity of 99.2 ± 0.4% at a sample throughput of 10 μl/min. The experiment is also conducted to show the feasibility of this mechanism to separate biological cells with the sample solutions of spiked PC3 cells in whole blood. By virtue of its high separation efficiency, our device offers a label-free separation technique and potential integration with other components, thereby serving as a promising tool for continuous cell filtration and analysis applications. PMID:26858812

  13. Enhancement of microfluidic particle separation using cross-flow filters with hydrodynamic focusing.

    PubMed

    Chiu, Yun-Yen; Huang, Chen-Kang; Lu, Yen-Wen

    2016-01-01

    A microfluidic chip is proposed to separate microparticles using cross-flow filtration enhanced with hydrodynamic focusing. By exploiting a buffer flow from the side, the microparticles in the sample flow are pushed on one side of the microchannels, lining up to pass through the filters. Meanwhile a larger pressure gradient in the filters is obtained to enhance separation efficiency. Compared with the traditional cross-flow filtration, our proposed mechanism has the buffer flow to create a moving virtual boundary for the sample flow to actively push all the particles to reach the filters for separation. It further allows higher flow rates. The device only requires soft lithograph fabrication to create microchannels and a novel pressurized bonding technique to make high-aspect-ratio filtration structures. A mixture of polystyrene microparticles with 2.7 μm and 10.6 μm diameters are successfully separated. 96.2 ± 2.8% of the large particle are recovered with a purity of 97.9 ± 0.5%, while 97.5 ± 0.4% of the small particle are depleted with a purity of 99.2 ± 0.4% at a sample throughput of 10 μl/min. The experiment is also conducted to show the feasibility of this mechanism to separate biological cells with the sample solutions of spiked PC3 cells in whole blood. By virtue of its high separation efficiency, our device offers a label-free separation technique and potential integration with other components, thereby serving as a promising tool for continuous cell filtration and analysis applications.

  14. Fault prediction for nonlinear stochastic system with incipient faults based on particle filter and nonlinear regression.

    PubMed

    Ding, Bo; Fang, Huajing

    2017-03-31

    This paper is concerned with the fault prediction for the nonlinear stochastic system with incipient faults. Based on the particle filter and the reasonable assumption about the incipient faults, the modified fault estimation algorithm is proposed, and the system state is estimated simultaneously. According to the modified fault estimation, an intuitive fault detection strategy is introduced. Once each of the incipient fault is detected, the parameters of which are identified by a nonlinear regression method. Then, based on the estimated parameters, the future fault signal can be predicted. Finally, the effectiveness of the proposed method is verified by the simulations of the Three-tank system.

  15. An Optimal Observing System Study for the Kuroshio Extension using Particle Filters

    NASA Astrophysics Data System (ADS)

    Kramer, Werner; van Leeuwen, Peter Jan; Pierieni, Stefano; Dijkstra, Henk

    2010-05-01

    The Kuroshio Extension - the eastward-flowing free jet formed when the warm waters of the Kuroshio separate from the Japanese coast - reveals bimodal behavior. It changes from an elongated, energetic meandering jet into a weaker, unstable jet with a reduced zonal penetration. Many of its characteristics, e.g. the decadal period and the more stable character of the elongated state, are also observed in a reduced-gravity ocean model of the northern Pacific basin with a schematic Japanese coastline driven by a constant double-gyre wind field. The success of this idealized model suggests that intrinsic nonlinear mechanisms play a major role in determining the meander pattern of the mean flow. The low complexity of the model makes it ideal to perform an observing system study. Here, we take a new approach by using particle filters to assimilate observations into the model. An ensemble of model states is integrated over time from an initial distribution. The first approach is to pick one run as the synthetic truth. Observations are produced from this synthetic truth with an additional observation error. The particle filter technique adjusts the weight of each ensemble run - each particle - according to the observation value and the error distribution. From the ensemble and its weight distribution the expectation and probability distribution of the state vector can be computed. As the ensemble itself is not altered by the filter, different sets of observations, e.g. with different geometrical configurations, locations and/or time resolutions, can be analyzed a posteriori. The particle filter analyses allows us to identify which observations have a large impact on reconstructing the true state of Kuroshio Extension. More precisely, which observations contribute to a (local) reduction in the entropy of the ensemble. In a way each observation is then linked to an area of influence, which permits for determining the flow of information. We will present results where

  16. Behaviour of advanced materials impacted by high energy particle beams

    NASA Astrophysics Data System (ADS)

    Bertarelli, A.; Carra, F.; Cerutti, F.; Dallocchio, A.; Garlasché, M.; Guinchard, M.; Mariani, N.; Marques dos Santos, S. D.; Peroni, L.; Scapin, M.; Boccone, V.

    2013-07-01

    Beam Intercepting Devices (BID) are designed to operate in a harsh radioactive environment and are highly loaded from a thermo-structural point of view. Moreover, modern particle accelerators, storing unprecedented energy, may be exposed to severe accidental events triggered by direct beam impacts. In this context, impulse has been given to the development of novel materials for advanced thermal management with high thermal shock resistance like metal-diamond and metal-graphite composites on top of refractory metals such as molybdenum, tungsten and copper alloys. This paper presents the results of a first-of-its-kind experiment which exploited 440 GeV proton beams at different intensities to impact samples of the aforementioned materials. Effects of thermally induced shockwaves were acquired via high speed acquisition system including strain gauges, laser Doppler vibrometer and high speed camera. Preliminary information of beam induced damages on materials were also collected. State-of-the-art hydrodynamic codes (like Autodyn®), relying on complex material models including equation of state (EOS), strength and failure models, have been used for the simulation of the experiment. Preliminary results confirm the effectiveness and reliability of these numerical methods when material constitutive models are completely available (W and Cu alloys). For novel composite materials a reverse engineering approach will be used to build appropriate constitutive models, thus allowing a realistic representation of these complex phenomena. These results are of paramount importance for understanding and predicting the response of novel advanced composites to beam impacts in modern particle accelerators.

  17. Artefact-reduced kinematics measurement using a geometric finger model with mixture-prior particle filtering.

    PubMed

    Chang, Cheung-Wen; Kuo, Li-Chieh; Jou, I-Ming; Su, Fong-Chin; Sun, Yung-Nien

    2013-01-01

    It is challenging to measure the finger's kinematics of underlying bones in vivo. This paper presents a new method of finger kinematics measurement, using a geometric finger model and several markers deliberately stuck on skin surface. Using a multiple-view camera system, the optimal motion parameters of finger model were estimated using the proposed mixture-prior particle filtering. This prior, consisting of model and marker information, avoids generating improper particles for achieving near real-time performance. This method was validated using a planar fluoroscopy system that worked simultaneously with photographic system. Ten male subjects with asymptomatic hands were investigated in experiments. The results showed that the kinematic parameters could be estimated more accurately by the proposed method than by using only markers. There was 20-40% reduction in skin artefacts achieved for finger flexion/extension. Thus, this profile system can be developed as a tool of reliable kinematics measurement with good applicability for hand rehabilitation.

  18. Segmentation of Nerve Bundles and Ganglia in Spine MRI Using Particle Filters

    PubMed Central

    Dalca, Adrian; Danagoulian, Giovanna; Kikinis, Ron; Schmidt, Ehud; Golland, Polina

    2011-01-01

    Automatic segmentation of spinal nerve bundles that originate within the dural sac and exit the spinal canal is important for diagnosis and surgical planning. The variability in intensity, contrast, shape and direction of nerves seen in high resolution myelographic MR images makes segmentation a challenging task. In this paper, we present an automatic tracking method for nerve segmentation based on particle filters. We develop a novel approach to particle representation and dynamics, based on Bézier splines. Moreover, we introduce a robust image likelihood model that enables delineation of nerve bundles and ganglia from the surrounding anatomical structures. We demonstrate accurate and fast nerve tracking and compare it to expert manual segmentation. PMID:22003741

  19. EFFECT OF VENTILATION SYSTEMS AND AIR FILTERS ON DECAY RATES OF PARTICLES PRODUCED BY INDOOR SOURCES IN AN OCCUPIED TOWNHOUSE

    EPA Science Inventory

    Several studies have shown the importance of particle losses in real homes due to deposition and filtration; however, none have quantitatively shown the impact of using a central forced air fan and in-duct filter on particle loss rates. In an attempt to provide such data, we me...

  20. Biofuel-Promoted Polychlorinated Dibenzodioxin/furan Formation in an Iron-Catalyzed Diesel Particle Filter.

    PubMed

    Heeb, Norbert V; Rey, Maria Dolores; Zennegg, Markus; Haag, Regula; Wichser, Adrian; Schmid, Peter; Seiler, Cornelia; Honegger, Peter; Zeyer, Kerstin; Mohn, Joachim; Bürki, Samuel; Zimmerli, Yan; Czerwinski, Jan; Mayer, Andreas

    2015-08-04

    Iron-catalyzed diesel particle filters (DPFs) are widely used for particle abatement. Active catalyst particles, so-called fuel-borne catalysts (FBCs), are formed in situ, in the engine, when combusting precursors, which were premixed with the fuel. The obtained iron oxide particles catalyze soot oxidation in filters. Iron-catalyzed DPFs are considered as safe with respect to their potential to form polychlorinated dibenzodioxins/furans (PCDD/Fs). We reported that a bimetallic potassium/iron FBC supported an intense PCDD/F formation in a DPF. Here, we discuss the impact of fatty acid methyl ester (FAME) biofuel on PCDD/F emissions. The iron-catalyzed DPF indeed supported a PCDD/F formation with biofuel but remained inactive with petroleum-derived diesel fuel. PCDD/F emissions (I-TEQ) increased 23-fold when comparing biofuel and diesel data. Emissions of 2,3,7,8-TCDD, the most toxic congener [toxicity equivalence factor (TEF) = 1.0], increased 90-fold, and those of 2,3,7,8-TCDF (TEF = 0.1) increased 170-fold. Congener patterns also changed, indicating a preferential formation of tetra- and penta-chlorodibenzofurans. Thus, an inactive iron-catalyzed DPF becomes active, supporting a PCDD/F formation, when operated with biofuel containing impurities of potassium. Alkali metals are inherent constituents of biofuels. According to the current European Union (EU) legislation, levels of 5 μg/g are accepted. We conclude that risks for a secondary PCDD/F formation in iron-catalyzed DPFs increase when combusting potassium-containing biofuels.

  1. Particle image velocimetry (PIV) study of rotating cylindrical filters for animal cell perfusion processes.

    PubMed

    Figueredo-Cardero, Alvio; Chico, Ernesto; Castilho, Leda; de Andrade Medronho, Ricardo

    2012-01-01

    In the present work, the main fluid flow features inside a rotating cylindrical filtration (RCF) system used as external cell retention device for animal cell perfusion processes were investigated using particle image velocimetry (PIV). The motivation behind this work was to provide experimental fluid dynamic data for such turbulent flow using a high-permeability filter, given the lack of information about this system in the literature. The results shown herein gave evidence that, at the boundary between the filter mesh and the fluid, a slip velocity condition in the tangential direction does exist, which had not been reported in the literature so far. In the RCF system tested, this accounted for a fluid velocity 10% lower than that of the filter tip, which could be important for the cake formation kinetics during filtration. Evidence confirming the existence of Taylor vortices under conditions of turbulent flow and high permeability, typical of animal cell perfusion RCF systems, was obtained. Second-order turbulence statistics were successfully calculated. The radial behavior of the second-order turbulent moments revealed that turbulence in this system is highly anisotropic, which is relevant for performing numerical simulations of this system.

  2. Distributed multi-sensor particle filter for bearings-only tracking

    NASA Astrophysics Data System (ADS)

    Zhang, Jungen; Ji, Hongbing

    2012-02-01

    In this article, the classical bearings-only tracking (BOT) problem for a single target is addressed, which belongs to the general class of non-linear filtering problems. Due to the fact that the radial distance observability of the target is poor, the algorithm-based sequential Monte-Carlo (particle filtering, PF) methods generally show instability and filter divergence. A new stable distributed multi-sensor PF method is proposed for BOT. The sensors process their measurements at their sites using a hierarchical PF approach, which transforms the BOT problem from Cartesian coordinate to the logarithmic polar coordinate and separates the observable components from the unobservable components of the target. In the fusion centre, the target state can be estimated by utilising the multi-sensor optimal information fusion rule. Furthermore, the computation of a theoretical Cramer-Rao lower bound is given for the multi-sensor BOT problem. Simulation results illustrate that the proposed tracking method can provide better performances than the traditional PF method.

  3. The legacy of filter design and how that has extended into current choices for advanced astronomical filter

    NASA Astrophysics Data System (ADS)

    Hull, T.; Reichel, S.; Brauneck, U.; Naulin, V.; Marín-Franch, A.

    2016-07-01

    SCHOTT was one of the interference filters inventors starting around 1935. Based on this legacy optical bandpass filters were design, manufactured, and integrated into optical instruments in satellites. In addition a special blocking coating was developed reducing cross talk and ghost. For ground based telescopes steep-edge narrow bandpass filters with low transmitted wavefront error and about 100 mm x 100 mm size were manufactured pushing the filter design and the technology to its limits. The reached results for design and measurements will be shown on an H-alpha filter.

  4. A method for retrieving clouds with satellite infrared radiances using the particle filter

    NASA Astrophysics Data System (ADS)

    Xu, Dongmei; Auligné, Thomas; Descombes, Gaël; Snyder, Chris

    2016-11-01

    Ensemble-based techniques have been widely utilized in estimating uncertainties in various problems of interest in geophysical applications. A new cloud retrieval method is proposed based on the particle filter (PF) by using ensembles of cloud information in the framework of Gridpoint Statistical Interpolation (GSI) system. The PF cloud retrieval method is compared with the Multivariate Minimum Residual (MMR) method that was previously established and verified. Cloud retrieval experiments involving a variety of cloudy types are conducted with the PF and MMR methods with measurements of infrared radiances on multi-sensors onboard both geostationary and polar satellites, respectively. It is found that the retrieved cloud masks with both methods are consistent with other independent cloud products. MMR is prone to producing ambiguous small-fraction clouds, while PF detects clearer cloud signals, yielding closer heights of cloud top and cloud base to other references. More collections of small-fraction particles are able to effectively estimate the semi-transparent high clouds. It is found that radiances with high spectral resolutions contribute to quantitative cloud top and cloud base retrievals. In addition, a different way of resolving the filtering problem over each model grid is tested to better aggregate the weights with all available sensors considered, which is proven to be less constrained by the ordering of sensors. Compared to the MMR method, the PF method is overall more computationally efficient, and the cost of the model grid-based PF method scales more directly with the number of computing nodes.

  5. Particle filtering methods for georeferencing panoramic image sequence in complex urban scenes

    NASA Astrophysics Data System (ADS)

    Ji, Shunping; Shi, Yun; Shan, Jie; Shao, Xiaowei; Shi, Zhongchao; Yuan, Xiuxiao; Yang, Peng; Wu, Wenbin; Tang, Huajun; Shibasaki, Ryosuke

    2015-07-01

    Georeferencing image sequences is critical for mobile mapping systems. Traditional methods such as bundle adjustment need adequate and well-distributed ground control points (GCP) when accurate GPS data are not available in complex urban scenes. For applications of large areas, automatic extraction of GCPs by matching vehicle-born image sequences with geo-referenced ortho-images will be a better choice than intensive GCP collection with field surveying. However, such image matching generated GCP's are highly noisy, especially in complex urban street environments due to shadows, occlusions and moving objects in the ortho images. This study presents a probabilistic solution that integrates matching and localization under one framework. First, a probabilistic and global localization model is formulated based on the Bayes' rules and Markov chain. Unlike many conventional methods, our model can accommodate non-Gaussian observation. In the next step, a particle filtering method is applied to determine this model under highly noisy GCP's. Owing to the multiple hypotheses tracking represented by diverse particles, the method can balance the strength of geometric and radiometric constraints, i.e., drifted motion models and noisy GCP's, and guarantee an approximately optimal trajectory. Carried out tests are with thousands of mobile panoramic images and aerial ortho-images. Comparing with the conventional extended Kalman filtering and a global registration method, the proposed approach can succeed even under more than 80% gross errors in GCP's and reach a good accuracy equivalent to the traditional bundle adjustment with dense and precise control.

  6. Assimilation of microwave brightness temperatures for soil moisture estimation using particle filter

    NASA Astrophysics Data System (ADS)

    Bi, H. Y.; Ma, J. W.; Qin, S. X.; Zeng, J. Y.

    2014-03-01

    Soil moisture plays a significant role in global water cycles. Both model simulations and remote sensing observations have their limitations when estimating soil moisture on a large spatial scale. Data assimilation (DA) is a promising tool which can combine model dynamics and remote sensing observations to obtain more precise ground soil moisture distribution. Among various DA methods, the particle filter (PF) can be applied to non-linear and non-Gaussian systems, thus holding great potential for DA. In this study, a data assimilation scheme based on the residual resampling particle filter (RR-PF) was developed to assimilate microwave brightness temperatures into the macro-scale semi-distributed Variance Infiltration Capacity (VIC) Model to estimate surface soil moisture. A radiative transfer model (RTM) was used to link brightness temperatures with surface soil moisture. Finally, the data assimilation scheme was validated by experimental data obtained at Arizona during the Soil Moisture Experiment 2004 (SMEX04). The results show that the estimation accuracy of soil moisture can be improved significantly by RR-PF through assimilating microwave brightness temperatures into VIC model. Both the overall trends and specific values of the assimilation results are more consistent with ground observations compared with model simulation results.

  7. A Robust Indoor Autonomous Positioning System Using Particle Filter Based on ISM Band Wireless Communications

    NASA Astrophysics Data System (ADS)

    Ikeda, Takeshi; Kawamoto, Mitsuru; Sashima, Akio; Suzuki, Keiji; Kurumatani, Koichi

    In the field of the ubiquitous computing, positioning systems which can provide users' location information have paid attention as an important technical element which can be applied to various services, for example, indoor navigation services, evacuation services, market research services, guidance services, and so on. A lot of researchers have proposed various outdoor and indoor positioning systems. In this paper, we deal with indoor positioning systems. Many conventional indoor positioning systems use expensive infrastructures, because the propagated times of radio waves are used to measure users' positions with high accuracy. In this paper, we propose an indoor autonomous positioning system using radio signal strengths (RSSs) based on ISM band communications. In order to estimate users' positions, the proposed system utilizes a particle filter that is one of the Monte Carlo methods. Because the RSS information is used in the proposed system, the equipments configuring the system are not expensive compared with the conventional indoor positioning systems and it can be installed easily. Moreover, because the particle filter is used to estimate user's position, even if the RSS fluctuates due to, for example, multi-paths, the system can carry out position estimation robustly. We install the proposed system in one floor of a building and carry out some experiments in order to verify the validity of the proposed system. As a result, we confirmed that the average of the estimation errors of the proposed system was about 1.8 m, where the result is enough accuracy for achieving the services mentioned above.

  8. Deform PF-MT: Particle Filter With Mode Tracker for Tracking Nonaffine Contour Deformations

    PubMed Central

    Vaswani, Namrata; Rathi, Yogesh; Yezzi, Anthony; Tannenbaum, Allen

    2013-01-01

    We propose algorithms for tracking the boundary contour of a deforming object from an image sequence, when the nonaffine (local) deformation over consecutive frames is large and there is overlapping clutter, occlusions, low contrast, or outlier imagery. When the object is arbitrarily deforming, each, or at least most, contour points can move independently. Contour deformation then forms an infinite (in practice, very large), dimensional space. Direct application of particle filters (PF) for large dimensional problems is impractically expensive. However, in most real problems, at any given time, most of the contour deformation occurs in a small number of dimensions (“effective basis space”) while the residual deformation in the rest of the state space (“residual space”) is small. This property enables us to apply the particle filtering with mode tracking (PF-MT) idea that was proposed for such large dimensional problems in recent work. Since most contour deformation is low spatial frequency, we propose to use the space of deformation at a subsampled set of locations as the effective basis space. The resulting algorithm is called deform PF-MT. It requires significant modifications compared to the original PF-MT because the space of contours is a non-Euclidean infinite dimensional space. PMID:19933014

  9. Experimental Study on Ultrafine Particle Removal Performance of Portable Air Cleaners with Different Filters in an Office Room

    PubMed Central

    Ma, Huan; Shen, Henggen; Shui, Tiantian; Li, Qing; Zhou, Liuke

    2016-01-01

    Size- and time-dependent aerodynamic behaviors of indoor particles, including PM1.0, were evaluated in a school office in order to test the performance of air-cleaning devices using different filters. In-situ real-time measurements were taken using an optical particle counter. The filtration characteristics of filter media, including single-pass efficiency, volume and effectiveness, were evaluated and analyzed. The electret filter (EE) medium shows better initial removal efficiency than the high efficiency (HE) medium in the 0.3–3.5 μm particle size range, while under the same face velocity, the filtration resistance of the HE medium is several times higher than that of the EE medium. During service life testing, the efficiency of the EE medium decreased to 60% with a total purifying air flow of 25 × 104 m3/m2. The resistance curve rose slightly before the efficiency reached the bottom, and then increased almost exponentially. The single-pass efficiency of portable air cleaner (PAC) with the pre-filter (PR) or the active carbon granule filter (CF) was relatively poor. While PAC with the pre-filter and the high efficiency filter (PR&HE) showed maximum single-pass efficiency for PM1.0 (88.6%), PAC with the HE was the most effective at removing PM1.0. The enhancement of PR with HE and electret filters augmented the single-pass efficiency, but lessened the airflow rate and effectiveness. Combined with PR, the decay constant of large-sized particles could be greater than for PACs without PR. Without regard to the lifetime, the electret filters performed better with respect to resource saving and purification improvement. A most penetrating particle size range (MPPS: 0.4–0.65 μm) exists in both HE and electret filters; the MPPS tends to become larger after HE and electret filters are combined with PR. These results serve to provide a better understanding of the indoor particle removal performance of PACs when combined with different kinds of filters in school

  10. Wavelet-based SAR image despeckling and information extraction, using particle filter.

    PubMed

    Gleich, Dusan; Datcu, Mihai

    2009-10-01

    This paper proposes a new-wavelet-based synthetic aperture radar (SAR) image despeckling algorithm using the sequential Monte Carlo method. A model-based Bayesian approach is proposed. This paper presents two methods for SAR image despeckling. The first method, called WGGPF, models a prior with Generalized Gaussian (GG) probability density function (pdf) and the second method, called WGMPF, models prior with a Generalized Gaussian Markov random field (GGMRF). The likelihood pdf is modeled using a Gaussian pdf. The GGMRF model is used because it enables texture parameter estimation. The prior is modeled using GG pdf, when texture parameters are not needed. A particle filter is used for drawing particles from the prior for different shape parameters of GG pdf. When the GGMRF prior is used, the particles are drawn from prior in order to estimate noise-free wavelet coefficients and for those coefficients the texture parameter is changed in order to obtain the best textural parameters. The texture parameters are changed for a predefined set of shape parameters of GGMRF. The particles with the highest weights represents the final noise-free estimate with corresponding textural parameters. The despeckling algorithms are compared with the state-of-the-art methods using synthetic and real SAR data. The experimental results show that the proposed despeckling algorithms efficiently remove noise and proposed methods are comparable with the state-of-the-art methods regarding objective measurements. The proposed WGMPF preserves textures of the real, high-resolution SAR images well.

  11. Filterable redox cycling activity: a comparison between diesel exhaust particles and secondary organic aerosol constituents.

    PubMed

    McWhinney, Robert D; Badali, Kaitlin; Liggio, John; Li, Shao-Meng; Abbatt, Jonathan P D

    2013-04-02

    The redox activity of diesel exhaust particles (DEP) collected from a light-duty diesel passenger car engine was examined using the dithiothreitol (DTT) assay. DEP was highly redox-active, causing DTT to decay at a rate of 23-61 pmol min(-1) μg(-1) of particle used in the assay, which was an order of magnitude higher than ambient coarse and fine particulate matter (PM) collected from downtown Toronto. Only 2-11% of the redox activity was in the water-soluble portion, while the remainder occurred at the black carbon surface. This is in contrast to redox-active secondary organic aerosol constituents, in which upward of 90% of the activity occurs in the water-soluble fraction. The redox activity of DEP is not extractable by moderately polar (methanol) and nonpolar (dichloromethane) organic solvents, and is hypothesized to arise from redox-active moieties contiguous with the black carbon portion of the particles. These measurements illustrate that "Filterable Redox Cycling Activity" may therefore be useful to distinguish black carbon-based oxidative capacity from water-soluble organic-based activity. The difference in chemical environment leading to redox activity highlights the need to further examine the relationship between activity in the DTT assay and toxicology measurements across particles of different origins and composition.

  12. Bronchoalveolar inflammation after exposure to diesel exhaust: comparison between unfiltered and particle trap filtered exhaust

    PubMed Central

    Rudell, B.; Blomberg, A.; Helleday, R.; Ledin, M. C.; Lundback, B.; Stjernberg, N.; Horstedt, P.; Sandstrom, T.

    1999-01-01

    OBJECTIVES: Air pollution particulates have been identified as having adverse effects on respiratory health. The present study was undertaken to further clarify the effects of diesel exhaust on bronchoalveolar cells and soluble components in normal healthy subjects. The study was also designed to evaluate whether a ceramic particle trap at the end of the tail pipe, from an idling engine, would reduce indices of airway inflammation. METHODS: The study comprised three exposures in all 10 healthy never smoking subjects; air, diluted diesel exhaust, and diluted diesel exhaust filtered with a ceramic particle trap. The exposures were given for 1 hour in randomised order about 3 weeks apart. The diesel exhaust exposure apperatus has previously been carefully developed and evaluated. Bronchoalveolar lavage was performed 24 hours after exposures and the lavage fluids from the bronchial and bronchoalveolar region were analysed for cells and soluble components. RESULTS: The particle trap reduced the mean steady state number of particles by 50%, but the concentrations of the other measured compounds were almost unchanged. It was found that diesel exhaust caused an increase in neutrophils in airway lavage, together with an adverse influence on the phagocytosis by alveolar macrophages in vitro. Furthermore, the diesel exhaust was found to be able to induce a migration of alveolar macrophages into the airspaces, together with reduction in CD3+CD25+ cells. (CD = cluster of differentiation) The use of the specific ceramic particle trap at the end of the tail pipe was not sufficient to completely abolish these effects when interacting with the exhaust from an idling vehicle. CONCLUSIONS: The current study showed that exposure to diesel exhaust may induce neutrophil and alveolar macrophage recruitment into the airways and suppress alveolar macrophage function. The particle trap did not cause significant reduction of effects induced by diesel exhaust compared with unfiltered diesel

  13. Development of an Advanced Recycle Filter Tank Assembly for the ISS Urine Processor Assembly

    NASA Technical Reports Server (NTRS)

    Link, Dwight E., Jr.; Carter, Donald Layne; Higbie, Scott

    2010-01-01

    Recovering water from urine is a process that is critical to supporting larger crews for extended missions aboard the International Space Station. Urine is collected, preserved, and stored for processing into water and a concentrated brine solution that is highly toxic and must be contained to avoid exposure to the crew. The brine solution is collected in an accumulator tank, called a Recycle Filter Tank Assembly (RFTA) that must be replaced monthly and disposed in order to continue urine processing operations. In order to reduce resupply requirements, a new accumulator tank is being developed that can be emptied on orbit into existing ISS waste tanks. The new tank, called the Advanced Recycle Filter Tank Assembly (ARFTA) is a metal bellows tank that is designed to collect concentrated brine solution and empty by applying pressure to the bellows. This paper discusses the requirements and design of the ARFTA as well as integration into the urine processor assembly.

  14. Tightly coupled low cost 3D RISS/GPS integration using a mixture particle filter for vehicular navigation.

    PubMed

    Georgy, Jacques; Noureldin, Aboelmagd

    2011-01-01

    Satellite navigation systems such as the global positioning system (GPS) are currently the most common technique used for land vehicle positioning. However, in GPS-denied environments, there is an interruption in the positioning information. Low-cost micro-electro mechanical system (MEMS)-based inertial sensors can be integrated with GPS and enhance the performance in denied GPS environments. The traditional technique for this integration problem is Kalman filtering (KF). Due to the inherent errors of low-cost MEMS inertial sensors and their large stochastic drifts, KF, with its linearized models, has limited capabilities in providing accurate positioning. Particle filtering (PF) was recently suggested as a nonlinear filtering technique to accommodate for arbitrary inertial sensor characteristics, motion dynamics and noise distributions. An enhanced version of PF called the Mixture PF is utilized in this study to perform tightly coupled integration of a three dimensional (3D) reduced inertial sensors system (RISS) with GPS. In this work, the RISS consists of one single-axis gyroscope and a two-axis accelerometer used together with the vehicle's odometer to obtain 3D navigation states. These sensors are then integrated with GPS in a tightly coupled scheme. In loosely-coupled integration, at least four satellites are needed to provide acceptable GPS position and velocity updates for the integration filter. The advantage of the tightly-coupled integration is that it can provide GPS measurement update(s) even when the number of visible satellites is three or lower, thereby improving the operation of the navigation system in environments with partial blockages by providing continuous aiding to the inertial sensors even during limited GPS satellite availability. To effectively exploit the capabilities of PF, advanced modeling for the stochastic drift of the vertically aligned gyroscope is used. In order to benefit from measurement updates for such drift, which are

  15. Tightly Coupled Low Cost 3D RISS/GPS Integration Using a Mixture Particle Filter for Vehicular Navigation

    PubMed Central

    Georgy, Jacques; Noureldin, Aboelmagd

    2011-01-01

    Satellite navigation systems such as the global positioning system (GPS) are currently the most common technique used for land vehicle positioning. However, in GPS-denied environments, there is an interruption in the positioning information. Low-cost micro-electro mechanical system (MEMS)-based inertial sensors can be integrated with GPS and enhance the performance in denied GPS environments. The traditional technique for this integration problem is Kalman filtering (KF). Due to the inherent errors of low-cost MEMS inertial sensors and their large stochastic drifts, KF, with its linearized models, has limited capabilities in providing accurate positioning. Particle filtering (PF) was recently suggested as a nonlinear filtering technique to accommodate for arbitrary inertial sensor characteristics, motion dynamics and noise distributions. An enhanced version of PF called the Mixture PF is utilized in this study to perform tightly coupled integration of a three dimensional (3D) reduced inertial sensors system (RISS) with GPS. In this work, the RISS consists of one single-axis gyroscope and a two-axis accelerometer used together with the vehicle’s odometer to obtain 3D navigation states. These sensors are then integrated with GPS in a tightly coupled scheme. In loosely-coupled integration, at least four satellites are needed to provide acceptable GPS position and velocity updates for the integration filter. The advantage of the tightly-coupled integration is that it can provide GPS measurement update(s) even when the number of visible satellites is three or lower, thereby improving the operation of the navigation system in environments with partial blockages by providing continuous aiding to the inertial sensors even during limited GPS satellite availability. To effectively exploit the capabilities of PF, advanced modeling for the stochastic drift of the vertically aligned gyroscope is used. In order to benefit from measurement updates for such drift, which are

  16. Study of nanoscale structural biology using advanced particle beam microscopy

    NASA Astrophysics Data System (ADS)

    Boseman, Adam J.

    This work investigates developmental and structural biology at the nanoscale using current advancements in particle beam microscopy. Typically the examination of micro- and nanoscale features is performed using scanning electron microscopy (SEM), but in order to decrease surface charging, and increase resolution, an obscuring conductive layer is applied to the sample surface. As magnification increases, this layer begins to limit the ability to identify nanoscale surface structures. A new technology, Helium Ion Microscopy (HIM), is used to examine uncoated surface structures on the cuticle of wild type and mutant fruit flies. Corneal nanostructures observed with HIM are further investigated by FIB/SEM to provide detailed three dimensional information about internal events occurring during early structural development. These techniques are also used to reconstruct a mosquito germarium in order to characterize unknown events in early oogenesis. Findings from these studies, and many more like them, will soon unravel many of the mysteries surrounding the world of developmental biology.

  17. Performance of Advanced Light Source particle beam diagnostics

    SciTech Connect

    Hinkson, J.

    1993-05-01

    The Advanced Light Source (ALS), a third-generation synchrotron radiation facility, is complete. The particle beam diagnostics have been installed and tested. The beam injection systems have been running for two years. We have performance data on beam position monitors, beam intensity monitors, scintillators, beam collimators, a 50 {Omega} Faraday cup, and broad-band striplines and kickers used in the linac, transport lines, and the booster synchrotron. The single-turn monitoring capability of the booster beam position monitoring system has been particularly useful for studying beam dynamics. Beam diagnostics for the storage ring are being commissioned. In this paper we describe each instrument, show its performance, and outline how the instruments are controlled and their output data displayed.

  18. The "Puck" energetic charged particle detector: Design, heritage, and advancements.

    PubMed

    Clark, G; Cohen, I; Westlake, J H; Andrews, G B; Brandt, P; Gold, R E; Gkioulidou, M A; Hacala, R; Haggerty, D; Hill, M E; Ho, G C; Jaskulek, S E; Kollmann, P; Mauk, B H; McNutt, R L; Mitchell, D G; Nelson, K S; Paranicas, C; Paschalidis, N; Schlemm, C E

    2016-08-01

    Energetic charged particle detectors characterize a portion of the plasma distribution function that plays critical roles in some physical processes, from carrying the currents in planetary ring currents to weathering the surfaces of planetary objects. For several low-resource missions in the past, the need was recognized for a low-resource but highly capable, mass-species-discriminating energetic particle sensor that could also obtain angular distributions without motors or mechanical articulation. This need led to the development of a compact Energetic Particle Detector (EPD), known as the "Puck" EPD (short for hockey puck), that is capable of determining the flux, angular distribution, and composition of incident ions between an energy range of ~10 keV to several MeV. This sensor makes simultaneous angular measurements of electron fluxes from the tens of keV to about 1 MeV. The same measurements can be extended down to approximately 1 keV/nucleon, with some composition ambiguity. These sensors have a proven flight heritage record that includes missions such as MErcury Surface, Space ENvironment, GEochemistry, and Ranging and New Horizons, with multiple sensors on each of Juno, Van Allen Probes, and Magnetospheric Multiscale. In this review paper we discuss the Puck EPD design, its heritage, unexpected results from these past missions and future advancements. We also discuss high-voltage anomalies that are thought to be associated with the use of curved foils, which is a new foil manufacturing processes utilized on recent Puck EPD designs. Finally, we discuss the important role Puck EPDs can potentially play in upcoming missions.

  19. The "Puck" energetic charged particle detector: Design, heritage, and advancements

    NASA Astrophysics Data System (ADS)

    Clark, G.; Cohen, I.; Westlake, J. H.; Andrews, G. B.; Brandt, P.; Gold, R. E.; Gkioulidou, M. A.; Hacala, R.; Haggerty, D.; Hill, M. E.; Ho, G. C.; Jaskulek, S. E.; Kollmann, P.; Mauk, B. H.; McNutt, R. L.; Mitchell, D. G.; Nelson, K. S.; Paranicas, C.; Paschalidis, N.; Schlemm, C. E.

    2016-08-01

    Energetic charged particle detectors characterize a portion of the plasma distribution function that plays critical roles in some physical processes, from carrying the currents in planetary ring currents to weathering the surfaces of planetary objects. For several low-resource missions in the past, the need was recognized for a low-resource but highly capable, mass-species-discriminating energetic particle sensor that could also obtain angular distributions without motors or mechanical articulation. This need led to the development of a compact Energetic Particle Detector (EPD), known as the "Puck" EPD (short for hockey puck), that is capable of determining the flux, angular distribution, and composition of incident ions between an energy range of ~10 keV to several MeV. This sensor makes simultaneous angular measurements of electron fluxes from the tens of keV to about 1 MeV. The same measurements can be extended down to approximately 1 keV/nucleon, with some composition ambiguity. These sensors have a proven flight heritage record that includes missions such as MErcury Surface, Space ENvironment, GEochemistry, and Ranging and New Horizons, with multiple sensors on each of Juno, Van Allen Probes, and Magnetospheric Multiscale. In this review paper we discuss the Puck EPD design, its heritage, unexpected results from these past missions and future advancements. We also discuss high-voltage anomalies that are thought to be associated with the use of curved foils, which is a new foil manufacturing processes utilized on recent Puck EPD designs. Finally, we discuss the important role Puck EPDs can potentially play in upcoming missions.

  20. Climatological sensitivity analysis of crop yield to changes in temperature and precipitation using particle filter

    NASA Astrophysics Data System (ADS)

    Yokozawa, M.; Sakurai, G.; Iizumi, T.

    2010-12-01

    The climatological sensitivities of crop yields to changes in mean temperature and precipitation during a period of the growing season were statistically examined. The sensitivity is defined as the change of yield in response to the change of climatic condition in the growth period from sowing to harvesting. The objective crops are maize and soybean, which are being cultivated in United States, Brazil and China as the world major production countries. We collected the yield data of maize and soybean on county level of United States from USDA during a period of 1980-2006, on Município level of Brazil during a period of 1990-2006 and on Xiàn level of China during a period of 1980-2005. While the data on only four provinces in China are used (Heilongjiang, Henan, Liaoning, and Shandong), total production of the four provinces reaches about 40% (maize) and 51% (soybean) to the country total (USDA 1997). We used JRA-25 reanalysis climate data distributed from the Japanese Meteorological Agency during a period of 1980 through 2006 with a resolution of 1.125° in latitude and longitude. To coincide in resolution, the crop yield data were reallocated into the same grids as climate. To eliminate economical and technical effects on yield, we detrended the time series data of yield and climate. We applied a local regression model to conduct the detrend (cubic weighting and M estimator of Tukey's bi-weight function). The time series data on the deviation from the trend were examined with the changes in temperature and precipitation for each grid using the particle filter. The particle filter used here is based on self-organizing state-space model. As a result, in the northern hemisphere, positive sensitivity, i.e. increase in temperature shifts the crop yield positively, is generally found especially in higher latitude, while negative sensitivity is found in the lower latitude. The neutral sensitivity is found in the regions where the mean temperature during growing season

  1. Investigation on the internal acceleration process of the outer radiation belt using the particle filter

    NASA Astrophysics Data System (ADS)

    Toyama, H.; Miyoshi, Y.; Ueno, G.; Koshiishi, H.; Matsumoto, H.; Shiokawa, K.

    2013-12-01

    It is known that high energy electrons in the radiation belts often cause satellite anomalies and malfunctions. Thus, a forecast of the time variation of the energetic electrons is necessary to protect satellites in the radiation belts. Time variations of the radiation belt electrons have been modeled with the Fokker-Plank equation. Performance of the forecast using the Fokker-Planck equation depends on the parameters used in the model, so that improvement of the parameters is important for the space weather forecast. We performed data assimilation using the particle filter by a code which was developed by Miyoshi et al.[2006]. We prepare 1000 particles used for the calculation. In this study, phase space density, the diffusion coefficient, and wave amplitude, and the source amplitude of the internal acceleration compose the state vector. The observation vector consists of the differential flux measured by the Tsubasa satellite. We also apply the particle smoother to estimate the smoothed distribution. While there were several discrepancies between the simulation without the data assimilation and the observations, the data assimilation improves the simulation result, and captures the typical flux variations of the outer belt during magnetic storms. We also discuss the internal acceleration process on the basis of the source amplitude estimated through the data assimilation.

  2. A Framework for 3D Model-Based Visual Tracking Using a GPU-Accelerated Particle Filter.

    PubMed

    Brown, J A; Capson, D W

    2012-01-01

    A novel framework for acceleration of particle filtering approaches to 3D model-based, markerless visual tracking in monocular video is described. Specifically, we present a methodology for partitioning and mapping the computationally expensive weight-update stage of a particle filter to a graphics processing unit (GPU) to achieve particle- and pixel-level parallelism. Nvidia CUDA and Direct3D are employed to harness the massively parallel computational power of modern GPUs for simulation (3D model rendering) and evaluation (segmentation, feature extraction, and weight calculation) of hundreds of particles at high speeds. The proposed framework addresses the computational intensity that is intrinsic to all particle filter approaches, including those that have been modified to minimize the number of particles required for a particular task. Performance and tracking quality results for rigid object and articulated hand tracking experiments demonstrate markerless, model-based visual tracking on consumer-grade graphics hardware with pixel-level accuracy up to 95 percent at 60+ frames per second. The framework accelerates particle evaluation up to 49 times over a comparable CPU-only implementation, providing an increased particle count while maintaining real-time frame rates.

  3. Highly Integrated Polysulfone/polyacrylonitrile/polyamide-6 Air Filter for Multi-level Physical Sieving Airborne Particles.

    PubMed

    Zhang, Shichao; Tang, Ning; Cao, Leitao; Yin, Xia; Yu, Jianyong; Ding, Bin

    2016-10-04

    Rational structural design involving controlled pore size, high porosity, and particle-targeted function is critical to the realization of highly efficient air filters, and the filter with absolute particle-screen ability has significant technological implications for applications including individual protection, industrial security, and environmental governance; however, it remains an ongoing challenge. In this study, we first report a facile and scalable strategy to fabricate the highly integrated polysulfone/polyacrylonitrile/polyamide-6 (PSU/PAN/PA-6) air filter for multi-level physical sieving airborne particles via sequential electrospinning. Our strategy causes the PSU microfiber (diameter of ~1 μm) layer, PAN nanofiber (diameter of ~200 nm) layer, and PA-6 nanonets (diameter of ~20 nm) layer to orderly assemble into the integrated filter with gradually varied pore structures and high porosity; thus enables the filter to work efficiently by employing different layers to cut off penetration of particles with certain size that exceeds the designed threshold level. By virtue of its elaborate gradient structure, robust hydrophobicity (WCA of ~130o), and superior mechanical property (5.6 MPa), our PSU/PAN/PA-6 filter even can filtrate the 300 nm particles with a high removal efficiency of 99.992% and a low pressure drop of 118 Pa in the way of physical sieving manner, which completely gets rid of the negative impact from high airflow speed, electret failure, and high humidity. It is expected that our highly integrated filter has wider applications for filtration and separation, and design of 3D functional structure in the future.

  4. Mobile Robot Positioning with 433-MHz Wireless Motes with Varying Transmission Powers and a Particle Filter

    PubMed Central

    Canedo-Rodriguez, Adrian; Rodriguez, Jose Manuel; Alvarez-Santos, Victor; Iglesias, Roberto; Regueiro, Carlos V.

    2015-01-01

    In wireless positioning systems, the transmitter's power is usually fixed. In this paper, we explore the use of varying transmission powers to increase the performance of a wireless localization system. To this extent, we have designed a robot positioning system based on wireless motes. Our motes use an inexpensive, low-power sub-1-GHz system-on-chip (CC1110) working in the 433-MHz ISM band. Our localization algorithm is based on a particle filter and infers the robot position by: (1) comparing the power received with the expected one; and (2) integrating the robot displacement. We demonstrate that the use of transmitters that vary their transmission power over time improves the performance of the wireless positioning system significantly, with respect to a system that uses fixed power transmitters. This opens the door for applications where the robot can localize itself actively by requesting the transmitters to change their power in real time. PMID:25942641

  5. A numerical investigation of the diesel particle filter regeneration process under temperature pulse conditions

    NASA Astrophysics Data System (ADS)

    Meng, Zhongwei; Zhang, Jing; Chen, Chao; Yan, Yan

    2016-10-01

    A one-dimensional transient diesel particle filter (DPF) model is applied to study DPF regeneration performance. Numerical simulations are performed to predict the effects of various factors influencing regeneration performance under temperature pulse conditions, and the regeneration performances of three typical DPFs are compared and analyzed. Numerical results indicate that the thermal conductivity characteristics of DPF configurations can greatly affect soot oxidation, which in turn influences the regeneration process. The transition points of the regeneration flow rate indicate a balance between its promotion of the regeneration process and retardation owing to cooling effects. The sensitive ranges of soot loading, oxygen concentration, and inlet temperature are observed to provide a reference for controlling DPF regeneration. The multi-step exhaust condition is employed to control DPF regeneration. It was found that a transient increase in the flow rate is more effective at reducing the peak temperature and peak temperature gradient than a transient decrease of oxygen concentration.

  6. Indoor anti-occlusion visible light positioning systems based on particle filtering

    NASA Astrophysics Data System (ADS)

    Jiang, Meng; Huang, Zhitong; Li, Jianfeng; Zhang, Ruqi; Ji, Yuefeng

    2015-04-01

    As one of the most popular categories of mobile services, a rapid growth of indoor location-based services has been witnessed over the past decades. Indoor positioning methods based on Wi-Fi, radio-frequency identification or Bluetooth are widely commercialized; however, they have disadvantages such as low accuracy or high cost. An emerging method using visible light is under research recently. The existed visible light positioning (VLP) schemes using carrier allocation, time allocation and multiple receivers all have limitations. This paper presents a novel mechanism using particle filtering in VLP system. By this method no additional devices are needed and the occlusion problem in visible light would be alleviated which will effectively enhance the flexibility for indoor positioning.

  7. Particle Filter with Novel Nonlinear Error Model for Miniature Gyroscope-Based Measurement While Drilling Navigation.

    PubMed

    Li, Tao; Yuan, Gannan; Li, Wang

    2016-03-15

    The derivation of a conventional error model for the miniature gyroscope-based measurement while drilling (MGWD) system is based on the assumption that the errors of attitude are small enough so that the direction cosine matrix (DCM) can be approximated or simplified by the errors of small-angle attitude. However, the simplification of the DCM would introduce errors to the navigation solutions of the MGWD system if the initial alignment cannot provide precise attitude, especially for the low-cost microelectromechanical system (MEMS) sensors operated in harsh multilateral horizontal downhole drilling environments. This paper proposes a novel nonlinear error model (NNEM) by the introduction of the error of DCM, and the NNEM can reduce the propagated errors under large-angle attitude error conditions. The zero velocity and zero position are the reference points and the innovations in the states estimation of particle filter (PF) and Kalman filter (KF). The experimental results illustrate that the performance of PF is better than KF and the PF with NNEM can effectively restrain the errors of system states, especially for the azimuth, velocity, and height in the quasi-stationary condition.

  8. Particle Filter with Novel Nonlinear Error Model for Miniature Gyroscope-Based Measurement While Drilling Navigation

    PubMed Central

    Li, Tao; Yuan, Gannan; Li, Wang

    2016-01-01

    The derivation of a conventional error model for the miniature gyroscope-based measurement while drilling (MGWD) system is based on the assumption that the errors of attitude are small enough so that the direction cosine matrix (DCM) can be approximated or simplified by the errors of small-angle attitude. However, the simplification of the DCM would introduce errors to the navigation solutions of the MGWD system if the initial alignment cannot provide precise attitude, especially for the low-cost microelectromechanical system (MEMS) sensors operated in harsh multilateral horizontal downhole drilling environments. This paper proposes a novel nonlinear error model (NNEM) by the introduction of the error of DCM, and the NNEM can reduce the propagated errors under large-angle attitude error conditions. The zero velocity and zero position are the reference points and the innovations in the states estimation of particle filter (PF) and Kalman filter (KF). The experimental results illustrate that the performance of PF is better than KF and the PF with NNEM can effectively restrain the errors of system states, especially for the azimuth, velocity, and height in the quasi-stationary condition. PMID:26999130

  9. Fast Filtered Imaging of the C-2U Advanced Beam-Driven Field-Reversed Configuration

    NASA Astrophysics Data System (ADS)

    Granstedt, E. M.; Petrov, P.; Knapp, K.; Cordero, M.; Patel, V.; the TAE Team

    2015-11-01

    The goal of the C-2U program is to sustain a Field-Reversed Configuration (FRC) for 5+ ms using neutral beam injection, end-biasing, and various particle fueling techniques. Three high-speed, filtered cameras are used to observe visible light emission from deuterium pellet ablation and compact-toroid injection which are used for auxiliary particle fueling. The instruments are also used to view the dynamics of the macroscopic plasma evolution, identify regions of strong plasma-material interactions, and visualize non-axisymmetric perturbations. To achieve the necessary viewing geometry, imaging lenses are mounted in re-entrant viewports, two of which are mounted on bellows for retraction during gettering and removal if cleaning is necessary. Images are coupled from the imaging lens to the camera via custom lens-based optical periscopes. Each instrument contains a remote-controlled filter wheel which is set between shots to select a particular emission line from neutral D or various charge states of He, C, O, or Ti. Measurements of absolute emissivity and estimates of neutral and impurity density will be presented.

  10. Particle filter-based relative rolling estimation algorithm for non-cooperative infrared spacecraft

    NASA Astrophysics Data System (ADS)

    Li, Zhengzhou; Ge, Fengzeng; Chen, Wenhao; Shao, Wanxing; Liu, Bing; Cheng, Bei

    2016-09-01

    The issue of feature point mismatching among infrared image sequence would bring big challenge to estimating the relative motion of non-cooperative spacecraft for it couldn't provide the prior knowledge about its geometric structure and motion pattern. The paper introduces particle filter to precisely match the feature points within a desired region predicted by a kinetic equation, and presents a least square estimation-based algorithm to measure the relative rolling motion of non-cooperative spacecraft. The state transition equation and the measurement update equation of non-cooperative spacecraft are represented by establishing its kinetic equations, and then the relative pose measurement is converted to the maximum posteriori probability estimation via assuming the uncertainties about geometric structure and motion pattern as random and time-varying variables. These uncertainties would be interpreted and even solved through continuously measuring the image feature points of the rotating non-cooperative infrared spacecraft. Subsequently, the feature point is matched within a predicted region among sequence infrared image using particle filter algorithm to overcome the position estimation noise caused by the uncertainties of geometric structure and motion pattern. Finally, the position parameters including rotation motion are estimated by means of solving the minimum error of feature point mismatching using least square estimate theory. Both simulated and real infrared image sequences are induced in the experiment to evaluate the performance of the relative rolling estimation, and the experimental data show that the rolling motion estimated by the proposed algorithm is more robust to the feature extraction noise and various rotation speed. Meanwhile, the relative rolling estimation error would increase dramatically with distance and rotation speed increasing.

  11. Machine remaining useful life prediction: An integrated adaptive neuro-fuzzy and high-order particle filtering approach

    NASA Astrophysics Data System (ADS)

    Chen, Chaochao; Vachtsevanos, George; Orchard, Marcos E.

    2012-04-01

    Machine prognosis can be considered as the generation of long-term predictions that describe the evolution in time of a fault indicator, with the purpose of estimating the remaining useful life (RUL) of a failing component/subsystem so that timely maintenance can be performed to avoid catastrophic failures. This paper proposes an integrated RUL prediction method using adaptive neuro-fuzzy inference systems (ANFIS) and high-order particle filtering, which forecasts the time evolution of the fault indicator and estimates the probability density function (pdf) of RUL. The ANFIS is trained and integrated in a high-order particle filter as a model describing the fault progression. The high-order particle filter is used to estimate the current state and carry out p-step-ahead predictions via a set of particles. These predictions are used to estimate the RUL pdf. The performance of the proposed method is evaluated via the real-world data from a seeded fault test for a UH-60 helicopter planetary gear plate. The results demonstrate that it outperforms both the conventional ANFIS predictor and the particle-filter-based predictor where the fault growth model is a first-order model that is trained via the ANFIS.

  12. Optical Metrology for the Filter Set for the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS)

    NASA Technical Reports Server (NTRS)

    Leviton, Douglas B.; Boucarut, Rene A.; Content, David A.; Keski-Kuha, Ritva A.; Krebs, Carolyn A.; Miner, Linda A.; Norton, Todd A.; Mehalick, Kimberly; Petrone, Peter; Bush, Frank D.; Puc, Bernard; Standley, Clive; Tsvetanov, Zlatan; Kral, Catherine

    1998-01-01

    The Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) will employ a wide variety of spectral filtration components including narrow band, medium band, wide band, and far ultraviolet (FUV) long pass filters, spatially- variable filters (ramp filters), VIS/IR polarizers, NUV polarizers, FUV prisms, and a grism. These components are spread across ACS's Wide Field, High Resolution, and Solar Blind channels which provide diffraction-limited imaging of astronomical targets using aberration-correcting optics which remove most aberrations from HST's Optical Telescope Assembly (OTA). In order for ACS to be truly advanced, these filters must push the state-of-the-art in performance in a number of key areas at the same time. Important requirements which these filters must meet include outstanding transmitted wavefront, high transmittance, uniform transmittance across each filter, spectrally structure-free bandpasses, exceptionally high out of band rejection, and a high degree of parfocality. These constitute a very stringent set of requirements indeed, especially for filters which are up to 90 mm in diameter. The development of optical metrology stations used to demonstrate that each ACS filter will meet its design specifications is discussed. Of particular note are specially-designed spectral transmissometers and interferometers.

  13. Assimilation of Satellite Soil Moisture observation with the Particle Filter-Markov Chain Monte Carlo and Geostatistical Modeling

    NASA Astrophysics Data System (ADS)

    Moradkhani, Hamid; Yan, Hongxiang

    2016-04-01

    Soil moisture simulation and prediction are increasingly used to characterize agricultural droughts but the process suffers from data scarcity and quality. The satellite soil moisture observations could be used to improve model predictions with data assimilation. Remote sensing products, however, are typically discontinuous in spatial-temporal coverages; while simulated soil moisture products are potentially biased due to the errors in forcing data, parameters, and deficiencies of model physics. This study attempts to provide a detailed analysis of the joint and separate assimilation of streamflow and Advanced Scatterometer (ASCAT) surface soil moisture into a fully distributed hydrologic model, with the use of recently developed particle filter-Markov chain Monte Carlo (PF-MCMC) method. A geostatistical model is introduced to overcome the satellite soil moisture discontinuity issue where satellite data does not cover the whole study region or is significantly biased, and the dominant land cover is dense vegetation. The results indicate that joint assimilation of soil moisture and streamflow has minimal effect in improving the streamflow prediction, however, the surface soil moisture field is significantly improved. The combination of DA and geostatistical approach can further improve the surface soil moisture prediction.

  14. Novel particle and radiation sources and advanced materials

    NASA Astrophysics Data System (ADS)

    Mako, Frederick

    2016-03-01

    The influence Norman Rostoker had on the lives of those who had the pleasure of knowing him is profound. The skills and knowledge I gained as a graduate student researching collective ion acceleration has fueled a career that has evolved from particle beam physics to include particle and radiation source development and advanced materials research, among many other exciting projects. The graduate research performed on collective ion acceleration was extended by others to form the backbone for laser driven plasma ion acceleration. Several years after graduate school I formed FM Technologies, Inc., (FMT), and later Electron Technologies, Inc. (ETI). Currently, as the founder and president of both FMT and ETI, the Rostoker influence can still be felt. One technology that we developed is a self-bunching RF fed electron gun, called the Micro-Pulse Gun (MPG). The MPG has important applications for RF accelerators and microwave tube technology, specifically clinically improved medical linacs and "green" klystrons. In addition to electron beam and RF source research, knowledge of materials and material interactions gained indirectly in graduate school has blossomed into breakthroughs in materials joining technologies. Most recently, silicon carbide joining technology has been developed that gives robust helium leak tight, high temperature and high strength joints between ceramic-to-ceramic and ceramic-to-metal. This joining technology has the potential to revolutionize the ethylene production, nuclear fuel and solar receiver industries by finally allowing for the practical use of silicon carbide as furnace coils, fuel rods and solar receptors, respectively, which are applications that have been needed for decades.

  15. Diesel passenger car PM emissions: From Euro 1 to Euro 4 with particle filter

    NASA Astrophysics Data System (ADS)

    Tzamkiozis, Theodoros; Ntziachristos, Leonidas; Samaras, Zissis

    2010-03-01

    This paper examines the impact of the emission control and fuel technology development on the emissions of gaseous and, in particular, PM pollutants from diesel passenger cars. Three cars in five configurations in total were measured, and covered the range from Euro 1 to Euro 4 standards. The emission control ranged from no aftertreatment in the Euro 1 case, an oxidation catalyst in Euro 2, two oxidation catalysts and exhaust gas recirculation in Euro 3 and Euro 4, while a catalyzed diesel particle filter (DPF) fitted in the Euro 4 car led to a Euro 4 + DPF configuration. Both certification test and real-world driving cycles were employed. The results showed that CO and HC emissions were much lower than the emission standard over the hot-start real-world cycles. However, vehicle technologies from Euro 2 to Euro 4 exceeded the NOx and PM emission levels over at least one real-world cycle. The NOx emission level reached up to 3.6 times the certification level in case of the Euro 4 car. PM were up to 40% and 60% higher than certification level for the Euro 2 and Euro 3 cars, while the Euro 4 car emitted close or slightly below the certification level over the real-world driving cycles. PM mass reductions from Euro 1 to Euro 4 were associated with a relevant decrease in the total particle number, in particular over the certification test. This was not followed by a respective reduction in the solid particle number which remained rather constant between the four technologies at 0.86 × 10 14 km -1 (coefficient of variation 9%). As a result, the ratio of solid vs. total particle number ranged from ˜50% in Euro 1-100% in Euro 4. A significant reduction of more than three orders of magnitude in solid particle number is achieved with the introduction of the DPF. However, the potential for nucleation mode formation at high speed from the DPF car is an issue that needs to be considered in the over all assessment of its environmental benefit. Finally, comparison of the

  16. Particle filtering for tracking of GLUT4 vesicles in TIRF microscpy

    NASA Astrophysics Data System (ADS)

    Wu, Xiangping; Liu, Xiaofang; Xu, Wenglong; Yan, Dandan; Chen, Yongli

    2009-10-01

    GLUT4 is responsible for insulin-stimulated glucose uptake into fat cells and description of the dynamic behavior of it can give insight in some working mechanisms and structures of these cells. Quantitative analysis of the dynamical process requires tracking of hundreds of GLUT4 vesicles characterized as bright spots in noisy image sequences. In this paper, a 3D tracking algorithm built in Bayesian probabilistic framework is put forward, combined with the unique features of the TIRF microscopy. A brightness-correction procedure is firstly applied to ensure that the intensity of a vesicle is constant along time and is only affected by spatial factors. Then, tracking is formalized as a state estimation problem and a developed particle filter integrated by a sub-optimizer that steers the particles towards a region with high likelihood is used. Once each tracked vesicle is located in image plane, the depth information of a granule can be indirectly inferred according to the exponential relationship between its intensity and its vertical position. The experimental results indicate that the vesicles are tracked well under different motion styles. More, the algorithm provides the depth information of the tracked vesicle.

  17. Object tracking with adaptive HOG detector and adaptive Rao-Blackwellised particle filter

    NASA Astrophysics Data System (ADS)

    Rosa, Stefano; Paleari, Marco; Ariano, Paolo; Bona, Basilio

    2012-01-01

    Scenarios for a manned mission to the Moon or Mars call for astronaut teams to be accompanied by semiautonomous robots. A prerequisite for human-robot interaction is the capability of successfully tracking humans and objects in the environment. In this paper we present a system for real-time visual object tracking in 2D images for mobile robotic systems. The proposed algorithm is able to specialize to individual objects and to adapt to substantial changes in illumination and object appearance during tracking. The algorithm is composed by two main blocks: a detector based on Histogram of Oriented Gradient (HOG) descriptors and linear Support Vector Machines (SVM), and a tracker which is implemented by an adaptive Rao-Blackwellised particle filter (RBPF). The SVM is re-trained online on new samples taken from previous predicted positions. We use the effective sample size to decide when the classifier needs to be re-trained. Position hypotheses for the tracked object are the result of a clustering procedure applied on the set of particles. The algorithm has been tested on challenging video sequences presenting strong changes in object appearance, illumination, and occlusion. Experimental tests show that the presented method is able to achieve near real-time performances with a precision of about 7 pixels on standard video sequences of dimensions 320 × 240.

  18. Damage Detection in Flexible Plates through Reduced-Order Modeling and Hybrid Particle-Kalman Filtering.

    PubMed

    Capellari, Giovanni; Azam, Saeed Eftekhar; Mariani, Stefano

    2015-12-22

    Health monitoring of lightweight structures, like thin flexible plates, is of interest in several engineering fields. In this paper, a recursive Bayesian procedure is proposed to monitor the health of such structures through data collected by a network of optimally placed inertial sensors. As a main drawback of standard monitoring procedures is linked to the computational costs, two remedies are jointly considered: first, an order-reduction of the numerical model used to track the structural dynamics, enforced with proper orthogonal decomposition; and, second, an improved particle filter, which features an extended Kalman updating of each evolving particle before the resampling stage. The former remedy can reduce the number of effective degrees-of-freedom of the structural model to a few only (depending on the excitation), whereas the latter one allows to track the evolution of damage and to locate it thanks to an intricate formulation. To assess the effectiveness of the proposed procedure, the case of a plate subject to bending is investigated; it is shown that, when the procedure is appropriately fed by measurements, damage is efficiently and accurately estimated.

  19. Damage Detection in Flexible Plates through Reduced-Order Modeling and Hybrid Particle-Kalman Filtering

    PubMed Central

    Capellari, Giovanni; Eftekhar Azam, Saeed; Mariani, Stefano

    2015-01-01

    Health monitoring of lightweight structures, like thin flexible plates, is of interest in several engineering fields. In this paper, a recursive Bayesian procedure is proposed to monitor the health of such structures through data collected by a network of optimally placed inertial sensors. As a main drawback of standard monitoring procedures is linked to the computational costs, two remedies are jointly considered: first, an order-reduction of the numerical model used to track the structural dynamics, enforced with proper orthogonal decomposition; and, second, an improved particle filter, which features an extended Kalman updating of each evolving particle before the resampling stage. The former remedy can reduce the number of effective degrees-of-freedom of the structural model to a few only (depending on the excitation), whereas the latter one allows to track the evolution of damage and to locate it thanks to an intricate formulation. To assess the effectiveness of the proposed procedure, the case of a plate subject to bending is investigated; it is shown that, when the procedure is appropriately fed by measurements, damage is efficiently and accurately estimated. PMID:26703615

  20. State-of-charge estimation in lithium-ion batteries: A particle filter approach

    NASA Astrophysics Data System (ADS)

    Tulsyan, Aditya; Tsai, Yiting; Gopaluni, R. Bhushan; Braatz, Richard D.

    2016-11-01

    The dynamics of lithium-ion batteries are complex and are often approximated by models consisting of partial differential equations (PDEs) relating the internal ionic concentrations and potentials. The Pseudo two-dimensional model (P2D) is one model that performs sufficiently accurately under various operating conditions and battery chemistries. Despite its widespread use for prediction, this model is too complex for standard estimation and control applications. This article presents an original algorithm for state-of-charge estimation using the P2D model. Partial differential equations are discretized using implicit stable algorithms and reformulated into a nonlinear state-space model. This discrete, high-dimensional model (consisting of tens to hundreds of states) contains implicit, nonlinear algebraic equations. The uncertainty in the model is characterized by additive Gaussian noise. By exploiting the special structure of the pseudo two-dimensional model, a novel particle filter algorithm that sweeps in time and spatial coordinates independently is developed. This algorithm circumvents the degeneracy problems associated with high-dimensional state estimation and avoids the repetitive solution of implicit equations by defining a 'tether' particle. The approach is illustrated through extensive simulations.

  1. Human tracking in thermal images using adaptive particle filters with online random forest learning

    NASA Astrophysics Data System (ADS)

    Ko, Byoung Chul; Kwak, Joon-Young; Nam, Jae-Yeal

    2013-11-01

    This paper presents a fast and robust human tracking method to use in a moving long-wave infrared thermal camera under poor illumination with the existence of shadows and cluttered backgrounds. To improve the human tracking performance while minimizing the computation time, this study proposes an online learning of classifiers based on particle filters and combination of a local intensity distribution (LID) with oriented center-symmetric local binary patterns (OCS-LBP). Specifically, we design a real-time random forest (RF), which is the ensemble of decision trees for confidence estimation, and confidences of the RF are converted into a likelihood function of the target state. First, the target model is selected by the user and particles are sampled. Then, RFs are generated using the positive and negative examples with LID and OCS-LBP features by online learning. The learned RF classifiers are used to detect the most likely target position in the subsequent frame in the next stage. Then, the RFs are learned again by means of fast retraining with the tracked object and background appearance in the new frame. The proposed algorithm is successfully applied to various thermal videos as tests and its tracking performance is better than those of other methods.

  2. Challenge of N95 and P100 Filtering Facepiece Respirators with Particles Containing Viable H1N1

    DTIC Science & Technology

    2016-06-13

    Zhao B, Zhang Z, and Li X. 2005. Numerical study of the transport of droplets or particles generated by respiratory system indoors. Bldg. Environment... respiratory U U U SAR 35 Joseph D. Wander 850 283 6240 Reset Challenge of N95 and P100 Filtering Facepiece Respirators with Particles Containing...transmission include the use of respiratory protection devices in some situations. Furthermore, in the past decade, respirators have become commonplace

  3. Advances in sublimation studies for particles of explosives

    NASA Astrophysics Data System (ADS)

    Furstenberg, Robert; Nguyen, Viet; Fischer, Thomas; Abrishami, Tara; Papantonakis, Michael; Kendziora, Chris; Mott, David R.; McGill, R. Andrew

    2015-05-01

    When handling explosives, or related surfaces, the hands routinely become contaminated with particles of explosives and related materials. Subsequent contact with a solid surface results in particle crushing and deposition. These particles provide an evidentiary trail which is useful for security applications. As such, the opto-physico-chemical characteristics of these particles are critical to trace explosives detection applications in DOD or DHS arenas. As the persistence of these particles is vital to their forensic exploitation, it is important to understand which factors influence their persistence. The longevity or stability of explosives particles on a substrate is a function of several environmental parameters or particle properties including: Vapor pressure, particle geometry, airflow, particle field size, substrate topography, humidity, reactivity, adlayers, admixtures, particle areal density, and temperature. In this work we deposited particles of 2,4-dinitrotoluene on standard microscopy glass slides by particle sieving and studied their sublimation as a function of airflow velocity, areal particle density and particle field size. Analysis of 2D microscopic images was used to compute and track particle size and geometrical characteristics. The humidity, temperature and substrate type were kept constant for each experiment. A custom airflow cell, using standard microscopy glass slide, allowed in-situ photomicroscopy. Areal particle densities and airflow velocities were selected to provide relevant loadings and flow velocities for a range of potential applications. For a chemical of interest, we define the radial sublimation velocity (RSV) for the equivalent sphere of a particle as the parameter to characterize the sublimation rate. The RSV is a useful parameter because it is independent of particle size. The sublimation rate for an ensemble of particles was found to significantly depend on airflow velocity, the areal density of the particles, and the

  4. Filtered sub-grid constitutive models for fluidized gas-particle flows constructed from 3-D simulations

    SciTech Connect

    Sarkar, Avik; Milioli, Fernando E.; Ozarkar, Shailesh; Li, Tingwen; Sun, Xin; Sundaresan, Sankaran

    2016-10-01

    The accuracy of fluidized-bed CFD predictions using the two-fluid model can be improved significantly, even when using coarse grids, by replacing the microscopic kinetic-theory-based closures with coarse-grained constitutive models. These coarse-grained constitutive relationships, called filtered models, account for the unresolved gas-particle structures (clusters and bubbles) via sub-grid corrections. Following the previous 2-D approaches of Igci et al. [AIChE J., 54(6), 1431-1448, 2008] and Milioli et al. [AIChE J., 59(9), 3265-3275, 2013], new filtered models are constructed from highly-resolved 3-D simulations of gas-particle flows. Although qualitatively similar to the older 2-D models, the new 3-D relationships exhibit noticeable quantitative and functional differences. In particular, the filtered stresses are strongly dependent on the gas-particle slip velocity. Closures for the filtered inter-phase drag, gas- and solids-phase pressures and viscosities are reported. A new model for solids stress anisotropy is also presented. These new filtered 3-D constitutive relationships are better suited to practical coarse-grid 3-D simulations of large, commercial-scale devices.

  5. Effect of ventilation systems and air filters on decay rates of particles produced by indoor sources in an occupied townhouse

    NASA Astrophysics Data System (ADS)

    Howard-Reed, Cynthia; Wallace, Lance A.; Emmerich, Steven J.

    Several studies have shown the importance of particle losses in real homes due to deposition and filtration; however, none have quantitatively shown the impact of using a central forced air fan and in-duct filter on particle loss rates. In an attempt to provide such data, we measured the deposition of particles ranging from 0.3 to 10 μm in an occupied townhouse and also in an unoccupied test house. Experiments were run with three different sources (cooking with a gas stove, citronella candle, pouring kitty litter), with the central heating and air conditioning (HAC) fan on or off, and with two different types of in-duct filters (electrostatic precipitator and ordinary furnace filter). Particle size, HAC fan operation, and the electrostatic precipitator had significant effects on particle loss rates. The standard furnace filter had no effect. Surprisingly, the type of source (combustion vs. mechanical generation) and the type of furnishings (fully furnished including carpet vs. largely unfurnished including mostly bare floor) also had no measurable effect on the deposition rates of particles of comparable size. With the HAC fan off, average deposition rates varied from 0.3 h -1 for the smallest particle range (0.3-0.5 μm) to 5.2 h -1 for particles greater than 10 μm. Operation of the central HAC fan approximately doubled these rates for particles <5 μm, and increased rates by 2 h -1 for the larger particles. An in-duct electrostatic precipitator increased the loss rates compared to the fan-off condition by factors of 5-10 for particles <2.5 μm, and by a factor of 3 for 2.5-5.0 μm particles. In practical terms, use of the central fan alone could reduce indoor particle concentrations by 25-50%, and use of an in-duct ESP could reduce particle concentrations by 55-85% compared to fan-off conditions.

  6. MODIS SCA assimilation with the particle filter for improving discharge simulation

    NASA Astrophysics Data System (ADS)

    Thirel, G.; Salamon, P.; Burek, P.; Kalas, M.

    2012-04-01

    LISFLOOD is a distributed, semi-physical rainfall-runoff model designed for the simulation of hydrological processes in medium to large scale river basins. This model is used at the European Commission Joint Research Centre for studying floods, global hydrological changes and droughts. LISFLOOD is the basis of the European Flood Alert System (EFAS), which is a real-time probabilistic flood prediction system with a lead-time of up to 10 days. The aim of this study is to evaluate the feasibility of assimilation of satellite snow data into LISFLOOD. Furthermore, the impact of the assimilation on the snow simulation as well as on discharge will be assessed. For this purpose, MODIS Snow Cover Area (SCA) has been used here. Since cloud coverage limits the availability of MODIS data, we implemented methods for improving the data set, such as - combination of the data from the two MODIS satellites - merging data from previous days - extrapolate data from neighboring pixels - extrapolate data from pixels with similar altitudes. The data provided by the MODIS satellites is SCA, i.e. presence or not of snow, whereas the LISFLOOD model simulates Snow Water Equivalent (SWE). For the conversion from SWE to SCA we employed a snow depletion curve. The assimilation method used is the particle filter. This method is based on multiple perturbed simulations of the model, which at each assimilation time step are either kept or removed based on the similarity between the modeled SCA and the observed SCA (i.e., MODIS data). One major advantage of the particle filter as applied here is, that model states are not modified directly and hence the model conserves the mass balance throughout the assimilation. Tests have been performed on synthetic data (normal LISFLOOD SCA used as observations) on a small basin (1-dimensional problem) and on a larger basin (7-dimensional problem), both located in the Czech Morava River basin. These experiments showed the positive performance of the

  7. Advanced Kalman Filter for Real-Time Responsiveness in Complex Systems

    SciTech Connect

    Welch, Gregory Francis

    2014-06-10

    Complex engineering systems pose fundamental challenges in real-time operations and control because they are highly dynamic systems consisting of a large number of elements with severe nonlinearities and discontinuities. Today’s tools for real-time complex system operations are mostly based on steady state models, unable to capture the dynamic nature and too slow to prevent system failures. We developed advanced Kalman filtering techniques and the formulation of dynamic state estimation using Kalman filtering techniques to capture complex system dynamics in aiding real-time operations and control. In this work, we looked at complex system issues including severe nonlinearity of system equations, discontinuities caused by system controls and network switches, sparse measurements in space and time, and real-time requirements of power grid operations. We sought to bridge the disciplinary boundaries between Computer Science and Power Systems Engineering, by introducing methods that leverage both existing and new techniques. While our methods were developed in the context of electrical power systems, they should generalize to other large-scale scientific and engineering applications.

  8. Fabrication of a multi-walled carbon nanotube-deposited glass fiber air filter for the enhancement of nano and submicron aerosol particle filtration and additional antibacterial efficacy.

    PubMed

    Park, Jae Hong; Yoon, Ki Young; Na, Hyungjoo; Kim, Yang Seon; Hwang, Jungho; Kim, Jongbaeg; Yoon, Young Hun

    2011-09-01

    We grew multi-walled carbon nanotubes (MWCNTs) on a glass fiber air filter using thermal chemical vapor deposition (CVD) after the filter was catalytically activated with a spark discharge. After the CNT deposition, filtration and antibacterial tests were performed with the filters. Potassium chloride (KCl) particles (<1 μm) were used as the test aerosol particles, and their number concentration was measured using a scanning mobility particle sizer. Antibacterial tests were performed using the colony counting method, and Escherichia coli (E. coli) was used as the test bacteria. The results showed that the CNT deposition increased the filtration efficiency of nano and submicron-sized particles, but did not increase the pressure drop across the filter. When a pristine glass fiber filter that had no CNTs was used, the particle filtration efficiencies at particle sizes under 30 nm and near 500 nm were 48.5% and 46.8%, respectively. However, the efficiencies increased to 64.3% and 60.2%, respectively, when the CNT-deposited filter was used. The reduction in the number of viable cells was determined by counting the colony forming units (CFU) of each test filter after contact with the cells. The pristine glass fiber filter was used as a control, and 83.7% of the E. coli were inactivated on the CNT-deposited filter.

  9. Particle filter based hybrid prognostics for health monitoring of uncertain systems in bond graph framework

    NASA Astrophysics Data System (ADS)

    Jha, Mayank Shekhar; Dauphin-Tanguy, G.; Ould-Bouamama, B.

    2016-06-01

    The paper's main objective is to address the problem of health monitoring of system parameters in Bond Graph (BG) modeling framework, by exploiting its structural and causal properties. The system in feedback control loop is considered uncertain globally. Parametric uncertainty is modeled in interval form. The system parameter is undergoing degradation (prognostic candidate) and its degradation model is assumed to be known a priori. The detection of degradation commencement is done in a passive manner which involves interval valued robust adaptive thresholds over the nominal part of the uncertain BG-derived interval valued analytical redundancy relations (I-ARRs). The latter forms an efficient diagnostic module. The prognostics problem is cast as joint state-parameter estimation problem, a hybrid prognostic approach, wherein the fault model is constructed by considering the statistical degradation model of the system parameter (prognostic candidate). The observation equation is constructed from nominal part of the I-ARR. Using particle filter (PF) algorithms; the estimation of state of health (state of prognostic candidate) and associated hidden time-varying degradation progression parameters is achieved in probabilistic terms. A simplified variance adaptation scheme is proposed. Associated uncertainties which arise out of noisy measurements, parametric degradation process, environmental conditions etc. are effectively managed by PF. This allows the production of effective predictions of the remaining useful life of the prognostic candidate with suitable confidence bounds. The effectiveness of the novel methodology is demonstrated through simulations and experiments on a mechatronic system.

  10. Epileptic Seizure Prediction by a System of Particle Filter Associated with a Neural Network

    NASA Astrophysics Data System (ADS)

    Liu, Derong; Pang, Zhongyu; Wang, Zhuo

    2009-12-01

    None of the current epileptic seizure prediction methods can widely be accepted, due to their poor consistency in performance. In this work, we have developed a novel approach to analyze intracranial EEG data. The energy of the frequency band of 4-12 Hz is obtained by wavelet transform. A dynamic model is introduced to describe the process and a hidden variable is included. The hidden variable can be considered as indicator of seizure activities. The method of particle filter associated with a neural network is used to calculate the hidden variable. Six patients' intracranial EEG data are used to test our algorithm including 39 hours of ictal EEG with 22 seizures and 70 hours of normal EEG recordings. The minimum least square error algorithm is applied to determine optimal parameters in the model adaptively. The results show that our algorithm can successfully predict 15 out of 16 seizures and the average prediction time is 38.5 minutes before seizure onset. The sensitivity is about 93.75% and the specificity (false prediction rate) is approximately 0.09 FP/h. A random predictor is used to calculate the sensitivity under significance level of 5%. Compared to the random predictor, our method achieved much better performance.

  11. Usefulness of Nonlinear Interpolation and Particle Filter in Zigbee Indoor Positioning

    NASA Astrophysics Data System (ADS)

    Zhang, Xiang; Wu, Helei; Uradziński, Marcin

    2014-12-01

    The key to fingerprint positioning algorithm is establishing effective fingerprint information database based on different reference nodes of received signal strength indicator (RSSI). Traditional method is to set the location area calibration multiple information sampling points, and collection of a large number sample data what is very time consuming. With Zigbee sensor networks as platform, considering the influence of positioning signal interference, we proposed an improved algorithm of getting virtual database based on polynomial interpolation, while the pre-estimated result was disposed by particle filter. Experimental result shows that this method can generate a quick, simple fine-grained localization information database, and improve the positioning accuracy at the same time. Kluczem do algorytmu pozycjonowania wykorzystującego metodę fi ngerprinting jest ustanowienie skutecznej bazy danych na podstawie informacji z radiowych nadajników referencyjnych przy wykorzystaniu wskaźnika mocy odbieranego sygnału (RSSI). Tradycyjna metoda oparta jest na przeprowadzeniu kalibracji obszaru lokalizacji na podstawie wielu punktów pomiarowych i otrzymaniu dużej liczby próbek, co jest bardzo czasochłonne.

  12. Air quality benefits of universal particle filter and NOx controls on diesel trucks

    NASA Astrophysics Data System (ADS)

    Tao, L.; Mcdonald, B. C.; Harley, R.

    2015-12-01

    Heavy-duty diesel trucks are a major source of black carbon/particulate matter and nitrogen oxide emissions on urban and regional scales. These emissions are relevant to both air quality and climate change. Since 2010 in the US, new engines are required to be equipped with emission control systems that greatly reduce both PM and NOx emissions, by ~98% relative to 1988 levels. To reduce emissions from the legacy fleet of older trucks that still remain on the road, regulations have been adopted in Califonia to accelerate the replacement of older trucks and thereby reduce associated emissions of PM and NOx. Use of diesel particle filters will be widespread by 2016, and universal use of catalytic converters for NOx control is required by 2023. We assess the air quality consequences of this clean-up effort in Southern California, using the Community Multiscale Air Quality model (CMAQ), and comparing three scenarios: historical (2005), present day (2016), and future year (2023). Emissions from the motor vehicle sector are mapped at high spatial resolution based on traffic count and fuel sales data. NOx emissions from diesel engines in 2023 are expected to decrease by ~80% compared to 2005, while the fraction of NOx emitted as NO2 is expected to increase from 5 to 18%. Air quality model simulations will be analyzed to quantify changes in NO2, black carbon, particulate matter, and ozone, both basin-wide and near hot spots such as ports and major highways.

  13. Particle Filters and Occlusion Handling for Rigid 2D-3D Pose Tracking

    PubMed Central

    Lee, Jehoon; Sandhu, Romeil; Tannenbaum, Allen

    2013-01-01

    In this paper, we address the problem of 2D-3D pose estimation. Specifically, we propose an approach to jointly track a rigid object in a 2D image sequence and to estimate its pose (position and orientation) in 3D space. We revisit a joint 2D segmentation/3D pose estimation technique, and then extend the framework by incorporating a particle filter to robustly track the object in a challenging environment, and by developing an occlusion detection and handling scheme to continuously track the object in the presence of occlusions. In particular, we focus on partial occlusions that prevent the tracker from extracting an exact region properties of the object, which plays a pivotal role for region-based tracking methods in maintaining the track. To this end, a dynamical choice of how to invoke the objective functional is performed online based on the degree of dependencies between predictions and measurements of the system in accordance with the degree of occlusion and the variation of the object’s pose. This scheme provides the robustness to deal with occlusions of an obstacle with different statistical properties from that of the object of interest. Experimental results demonstrate the practical applicability and robustness of the proposed method in several challenging scenarios. PMID:24058277

  14. Adaptive Particle Filter for Nonparametric Estimation with Measurement Uncertainty in Wireless Sensor Networks.

    PubMed

    Li, Xiaofan; Zhao, Yubin; Zhang, Sha; Fan, Xiaopeng

    2016-05-30

    Particle filters (PFs) are widely used for nonlinear signal processing in wireless sensor networks (WSNs). However, the measurement uncertainty makes the WSN observations unreliable to the actual case and also degrades the estimation accuracy of the PFs. In addition to the algorithm design, few works focus on improving the likelihood calculation method, since it can be pre-assumed by a given distribution model. In this paper, we propose a novel PF method, which is based on a new likelihood fusion method for WSNs and can further improve the estimation performance. We firstly use a dynamic Gaussian model to describe the nonparametric features of the measurement uncertainty. Then, we propose a likelihood adaptation method that employs the prior information and a belief factor to reduce the measurement noise. The optimal belief factor is attained by deriving the minimum Kullback-Leibler divergence. The likelihood adaptation method can be integrated into any PFs, and we use our method to develop three versions of adaptive PFs for a target tracking system using wireless sensor network. The simulation and experimental results demonstrate that our likelihood adaptation method has greatly improved the estimation performance of PFs in a high noise environment. In addition, the adaptive PFs are highly adaptable to the environment without imposing computational complexity.

  15. Microtubule dynamics analysis using kymographs and variable-rate particle filters.

    PubMed

    Smal, Ihor; Grigoriev, Ilya; Akhmanova, Anna; Niessen, Wiro J; Meijering, Erik

    2010-07-01

    Studying intracellular dynamics is of fundamental importance for understanding healthy life at the molecular level and for developing drugs to target disease processes. One of the key technologies to enable this research is the automated tracking and motion analysis of these objects in microscopy image sequences. To make better use of the spatiotemporal information than common frame-by-frame tracking methods, two alternative approaches have recently been proposed, based upon either Bayesian estimation or space-time segmentation. In this paper, we propose to combine the power of both approaches, and develop a new probabilistic method to segment the traces of the moving objects in kymograph representations of the image data. It is based on variable-rate particle filtering and uses multiscale trend analysis of the extracted traces to estimate the relevant kinematic parameters. Experiments on realistic synthetically generated images as well as on real biological image data demonstrate the improved potential of the new method for the analysis of microtubule dynamics in vitro.

  16. Filtering coal-derived oil through a filter media precoated with particles partially solubilized by said oil

    DOEpatents

    Rodgers, Billy R.; Edwards, Michael S.

    1977-01-01

    Solids such as char, ash, and refractory organic compounds are removed from coal-derived liquids from coal liquefaction processes by the pressure precoat filtration method using particles of 85-350 mesh material selected from the group of bituminous coal, anthracite coal, lignite, and devolatilized coals as precoat materials and as body feed to the unfiltered coal-derived liquid.

  17. Study of the effect of humidity, particle hygroscopicity and size on the mass loading capacity of HEPA filters

    SciTech Connect

    Gupta, A.

    1992-09-01

    The effect of humidity, particle hygroscopicity and size on the mass loading capacity of glass fiber HEPA filters has been studied. At humidifies above the deliquescent point, the pressure drop across the HEPA filter increased non-linearly with the areal loading density (mass collected/filtration area) of NaCl aerosol, thus significantly reducing the mass loading capacity of the filter compared to dry hygroscopic or non-hygroscopic particle mass loadings. The specific cake resistance, K{sub 2}, has been computed for different test conditions and used as a measure of the mass loading capacity. K. was found to decrease with increasing humidity for the non-hygroscopic aluminum oxide particles and the hygroscopic NaCl particles (at humidities below the deliquescent point). It is postulated that an increase in humidity leads to the formation of a more open particulate cake which lowers the pressure drop for a given mass loading. A formula for predicting K{sub 2} for lognormally distributed aerosols (parameters obtained from impactor data) is derived. The resistance factor, R, calculated using this formula was compared to the theoretical R calculated using the Rudnick-Happel expression. For the non-hygroscopic aluminum oxide the agreement was good but for the hygroscopic sodium chloride, due to large variation in the cake porosity estimates, the agreement was poor.

  18. Effect of humidity and particle hygroscopicity on the mass loading capacity of high efficiency particulate air (HEPA) filters

    SciTech Connect

    Gupta, A.; Biswas, P. ); Monson, P.R. ); Novick, V.J. )

    1993-07-01

    The effect of humidity, particle hygroscopicity, and size on the mass loading capacity of glass fiber high efficiency particulate air filters was studied. Above the deliquescent point, the pressure drop across the filter increased nonlinearly with areal loading density (mass collected/filtration area) of a NaCl aerosol, thus significantly reducing the mass loading capacity of the filter compared to dry hygroscopic or nonhygroscopic particle mass loadings. The specific cake resistance K[sub 2] was computed for different test conditions and used as a measure of the mass loading capacity. K[sub 2] was found to decrease with increasing humidity for nonhygroscopic aluminum oxide particles and for hygroscopic NaCl particles (at humidities below the deliquescent point). It is postulated that an increase in humidity leads to the formation of a more open particulate cake which lowers the pressure drop for a given mass loading. A formula for predicting K[sub 2] for lognormally distributed aerosols (parameters obtained from impactor data) was derived. The resistance factor, R, calculated using this formula was compared to the theoretical R calculated using the Rudnick-Happel expression. For the nonhygroscopic aluminum oxide, the agreement was good but for the hygroscopic sodium chloride, due to large variation in the cake porosity estimates, the agreement was poor. 17 refs., 6 figs., 3 tabs.

  19. Study of the effect of humidity, particle hygroscopicity and size on the mass loading capacity of HEPA filters

    SciTech Connect

    Gupta, A.

    1992-01-01

    The effect of humidity, particle hygroscopicity and size on the mass loading capacity of glass fiber HEPA filters has been studied. At humidifies above the deliquescent point, the pressure drop across the HEPA filter increased non-linearly with the areal loading density (mass collected/filtration area) of NaCl aerosol, thus significantly reducing the mass loading capacity of the filter compared to dry hygroscopic or non-hygroscopic particle mass loadings. The specific cake resistance, K{sub 2}, has been computed for different test conditions and used as a measure of the mass loading capacity. K. was found to decrease with increasing humidity for the non-hygroscopic aluminum oxide particles and the hygroscopic NaCl particles (at humidities below the deliquescent point). It is postulated that an increase in humidity leads to the formation of a more open particulate cake which lowers the pressure drop for a given mass loading. A formula for predicting K{sub 2} for lognormally distributed aerosols (parameters obtained from impactor data) is derived. The resistance factor, R, calculated using this formula was compared to the theoretical R calculated using the Rudnick-Happel expression. For the non-hygroscopic aluminum oxide the agreement was good but for the hygroscopic sodium chloride, due to large variation in the cake porosity estimates, the agreement was poor.

  20. An adaptive non-local means filter for denoising live-cell images and improving particle detection.

    PubMed

    Yang, Lei; Parton, Richard; Ball, Graeme; Qiu, Zhen; Greenaway, Alan H; Davis, Ilan; Lu, Weiping

    2010-12-01

    Fluorescence imaging of dynamical processes in live cells often results in a low signal-to-noise ratio. We present a novel feature-preserving non-local means approach to denoise such images to improve feature recovery and particle detection. The commonly used non-local means filter is not optimal for noisy biological images containing small features of interest because image noise prevents accurate determination of the correct coefficients for averaging, leading to over-smoothing and other artifacts. Our adaptive method addresses this problem by constructing a particle feature probability image, which is based on Haar-like feature extraction. The particle probability image is then used to improve the estimation of the correct coefficients for averaging. We show that this filter achieves higher peak signal-to-noise ratio in denoised images and has a greater capability in identifying weak particles when applied to synthetic data. We have applied this approach to live-cell images resulting in enhanced detection of end-binding-protein 1 foci on dynamically extending microtubules in photo-sensitive Drosophila tissues. We show that our feature-preserving non-local means filter can reduce the threshold of imaging conditions required to obtain meaningful data.

  1. Developments in non-linear Kalman Ensemble and Particle Filtering techniques for hydrological data assimilation

    NASA Astrophysics Data System (ADS)

    Khaki, Mehdi; Forootan, Ehsan; Kuhn, Michael; Awange, Joseph; Pattiaratchi, Charitha

    2016-04-01

    Quantifying large-scale (basin/global) water storage changes is essential to understand the Earth's hydrological water cycle. Hydrological models have usually been used to simulate variations in storage compartments resulting from changes in water fluxes (i.e., precipitation, evapotranspiration and runoff) considering physical or conceptual frameworks. Models however represent limited skills in accurately simulating the storage compartments that could be the result of e.g., the uncertainty of forcing parameters, model structure, etc. In this regards, data assimilation provides a great chance to combine observational data with a prior forecast state to improve both the accuracy of model parameters and to improve the estimation of model states at the same time. Various methods exist that can be used to perform data assimilation into hydrological models. The one more frequently used particle-based algorithms suitable for non-linear systems high-dimensional systems is the Ensemble Kalman Filtering (EnKF). Despite efficiency and simplicity (especially in EnKF), this method indicate some drawbacks. To implement EnKF, one should use the sample covariance of observations and model state variables to update a priori estimates of the state variables. The sample covariance can be suboptimal as a result of small ensemble size, model errors, model nonlinearity, and other factors. Small ensemble can also lead to the development of correlations between state components that are at a significant distance from one another where there is no physical relation. To investigate the under-sampling issue raise by EnKF, covariance inflation technique in conjunction with localization was implemented. In this study, a comparison between latest methods used in the data assimilation framework, to overcome the mentioned problem, is performed. For this, in addition to implementing EnKF, we introduce and apply the Local Ensemble Kalman Filter (LEnKF) utilizing covariance localization to remove

  2. Energy-filtered TEM imaging and EELS study of ODS particles and argon-filled cavities in ferritic-martensitic steels.

    PubMed

    Klimiankou, M; Lindau, R; Möslang, A

    2005-01-01

    Oxide-dispersion-strengthened (ODS) ferritic-martensitic steels with yttrium oxide (Y(2)O(3)) have been produced by mechanical alloying and hot isostatic pressing for use as advanced material in fusion power reactors. Argon gas, usually widely used as inert gas during mechanical alloying, was surprisingly detected in the nanodispersion-strengthened materials. Energy-filtered transmission electron microscopy (EFTEM) and electron energy loss spectroscopy (EELS) led to the following results: (i) chemical composition of ODS particles, (ii) voids with typical diameters of 1-6 nm are formed in the matrix, (iii) these voids are filled with Ar gas, and (iv) the high-density nanosized ODS particles serve as trapping centers for the Ar bubbles. The Ar L(3,2) energy loss edge at 245 eV as well as the absorption features of the ODS particle elements were identified in the EELS spectrum. The energy resolution in the EEL spectrum of about 1.0 eV allows to identify the electronic structure of the ODS particles.

  3. An Analysis of Field-Aged Diesel Particulate Filter Performance: Particle Emissions Before, During and After Regeneration

    SciTech Connect

    Barone, Teresa L; Storey, John Morse; Domingo, Norberto

    2010-01-01

    A field-aged, passive diesel particulate filter (DPF) employed in a school bus retrofit program was evaluated for emissions of particle mass and number concentration before, during and after regeneration. For the particle mass measurements, filter samples were collected for gravimetric analysis with a partial flow sampling system, which sampled proportionally to the exhaust flow. Total number concentration and number-size distributions were measured by a condensation particle counter and scanning mobility particle sizer, respectively. The results of the evaluation show that the number concentration emissions decreased as the DPF became loaded with soot. However after soot removal by regeneration, the number concentration emissions were approximately 20 times greater, which suggests the importance of the soot layer in helping to trap particles. Contrary to the number concentration results, particle mass emissions decreased from 6 1 mg/hp-hr before regeneration to 3 2 mg/hp-hr after regeneration. This indicates that nanoparticles with diameter less than 50 nm may have been emitted after regeneration since these particles contribute little to the total mass. Overall, average particle emission reductions of 95% by mass and 10,000-fold by number concentration after four years of use provided evidence of the durability of a field-aged DPF. In contrast to previous reports for new DPFs in which elevated number concentrations occurred during the first 200 seconds of a transient cycle, the number concentration emissions were elevated during the second half of the heavy-duty federal test procedure when high speed was sustained. This information is relevant for the analysis of mechanisms by which particles are emitted from field-aged DPFs.

  4. An analysis of field-aged diesel particulate filter performance: particle emissions before, during, and after regeneration.

    PubMed

    Barone, Teresa L; Storey, John M E; Domingo, Norberto

    2010-08-01

    A field-aged, passive diesel particulate filter (DPF) used in a school bus retrofit program was evaluated for emissions of particle mass and number concentration before, during, and after regeneration. For the particle mass measurements, filter samples were collected for gravimetric analysis with a partial flow sampling system, which sampled proportionally to the exhaust flow. A condensation particle counter and scanning mobility particle sizer measured total number concentration and number-size distributions, respectively. The results of the evaluation show that the number concentration emissions decreased as the DPF became loaded with soot. However, after soot removal by regeneration, the number concentration emissions were approximately 20 times greater, which suggests the importance of the soot layer in helping to trap particles. Contrary to the number concentration results, particle mass emissions decreased from 6 +/- 1 mg/hp-hr before regeneration to 3 +/- 2 mg/hp-hr after regeneration. This indicates that nanoparticles with diameters less than 50 nm may have been emitted after regeneration because these particles contribute little to the total mass. Overall, average particle emission reductions of 95% by mass and 10,000-fold by number concentration after 4 yr of use provided evidence of the durability of a field-aged DPF. In contrast to previous reports for new DPFs in which elevated number concentrations occurred during the first 200 sec of a transient cycle, the number concentration emissions were elevated during the second half of the heavy-duty Federal Test Procedure (FTP) when high speed was sustained. This information is relevant for the analysis of mechanisms by which particles are emitted from field-aged DPFs.

  5. Biologically active filters - An advanced water treatment process for contaminants of emerging concern.

    PubMed

    Zhang, Shuangyi; Gitungo, Stephen W; Axe, Lisa; Raczko, Robert F; Dyksen, John E

    2017-05-01

    With the increasing concern of contaminants of emerging concern (CECs) in source water, this study examines the hypothesis that existing filters in water treatment plants can be converted to biologically active filters (BAFs) to treat these compounds. Removals through bench-scale BAFs were evaluated as a function of media, granular activated carbon (GAC) and dual media, empty bed contact time (EBCT), and pre-ozonation. For GAC BAFs, greater oxygen consumption, increased pH drop, and greater dissolved organic carbon removal normalized to adenosine triphosphate (ATP) were observed indicating increased microbial activity as compared to anthracite/sand dual media BAFs. ATP concentrations in the upper portion of the BAFs were as much as four times greater than the middle and lower portions of the dual media and 1.5 times greater in GAC. Sixteen CECs were spiked in the source water. At an EBCT of 18 min (min), GAC BAFs were highly effective with overall removals greater than 80% without pre-ozonation; exceptions included tri(2-chloroethyl) phosphate and iopromide. With a 10 min EBCT, the degree of CECs removal was reduced with less than half of the compounds removed at greater than 80%. The dual media BAFs showed limited CECs removal with only four compounds removed at greater than 80%, and 10 compounds were reduced by less than 50% with either EBCT. This study demonstrated that GAC BAFs with and without pre-ozonation are an effective and advanced technology for treating emerging contaminants. On the other hand, pre-ozonation is needed for dual media BAFs to remove CECs. The most cost effective operating conditions for dual media BAFs were a 10 min EBCT with the application of pre-ozonation.

  6. Biologically Induced Deposition of Fine Suspended Particles by Filter-Feeding Bivalves in Land-Based Industrial Marine Aquaculture Wastewater

    PubMed Central

    Zhou, Yi; Zhang, Shaojun; Liu, Ying; Yang, Hongsheng

    2014-01-01

    Industrial aquaculture wastewater contains large quantities of suspended particles that can be easily broken down physically. Introduction of macro-bio-filters, such as bivalve filter feeders, may offer the potential for treatment of fine suspended matter in industrial aquaculture wastewater. In this study, we employed two kinds of bivalve filter feeders, the Pacific oyster Crassostrea gigas and the blue mussel Mytilus galloprovincialis, to deposit suspended solids from marine fish aquaculture wastewater in flow-through systems. Results showed that the biodeposition rate of suspended particles by C. gigas (shell height: 8.67±0.99 cm) and M. galloprovincialis (shell height: 4.43±0.98 cm) was 77.84±7.77 and 6.37±0.67 mg ind−1•d−1, respectively. The total solid suspension (TSS) deposition rates of oyster and mussel treatments were 3.73±0.27 and 2.76±0.20 times higher than that of the control treatment without bivalves, respectively. The TSS deposition rates of bivalve treatments were significantly higher than the natural sedimentation rate of the control treatment (P<0.001). Furthermore, organic matter and C, N in the sediments of bivalve treatments were significantly lower than those in the sediments of the control (P<0.05). It was suggested that the filter feeders C. gigas and M. galloprovincialis had considerable potential to filter and accelerate the deposition of suspended particles from industrial aquaculture wastewater, and simultaneously yield value-added biological products. PMID:25250730

  7. Biologically induced deposition of fine suspended particles by filter-feeding bivalves in land-based industrial marine aquaculture wastewater.

    PubMed

    Zhou, Yi; Zhang, Shaojun; Liu, Ying; Yang, Hongsheng

    2014-01-01

    Industrial aquaculture wastewater contains large quantities of suspended particles that can be easily broken down physically. Introduction of macro-bio-filters, such as bivalve filter feeders, may offer the potential for treatment of fine suspended matter in industrial aquaculture wastewater. In this study, we employed two kinds of bivalve filter feeders, the Pacific oyster Crassostrea gigas and the blue mussel Mytilus galloprovincialis, to deposit suspended solids from marine fish aquaculture wastewater in flow-through systems. Results showed that the biodeposition rate of suspended particles by C. gigas (shell height: 8.67 ± 0.99 cm) and M. galloprovincialis (shell height: 4.43 ± 0.98 cm) was 77.84 ± 7.77 and 6.37 ± 0.67 mg ind(-1) • d(-1), respectively. The total solid suspension (TSS) deposition rates of oyster and mussel treatments were 3.73 ± 0.27 and 2.76 ± 0.20 times higher than that of the control treatment without bivalves, respectively. The TSS deposition rates of bivalve treatments were significantly higher than the natural sedimentation rate of the control treatment (P < 0.001). Furthermore, organic matter and C, N in the sediments of bivalve treatments were significantly lower than those in the sediments of the control (P < 0.05). It was suggested that the filter feeders C. gigas and M. galloprovincialis had considerable potential to filter and accelerate the deposition of suspended particles from industrial aquaculture wastewater, and simultaneously yield value-added biological products.

  8. Multi-faults detection and estimation for nonlinear stochastic system based on particle filter and hypothesis test

    NASA Astrophysics Data System (ADS)

    Ding, Bo; Fang, Huajing

    2016-12-01

    This paper is concerned with the fault detection and estimation for nonlinear stochastic system with additive multi-faults. The states of system are estimated by the improved particle filter which composed of basic particle filter and preliminary fault estimation. Since the preliminary fault estimation contains noise, the faults are detected by the method of hypothesis testing, while the amplitude of each fault is estimated by the average of the sample of preliminary fault estimation. Meanwhile, the relationship of the sample size, the significance level of two types of error, the amplitude of fault and the variance of the error of preliminary fault estimation are also given. The effectiveness of the proposed method is verified by the simulation of three-vessel water tank system.

  9. Research on a Lamb Wave and Particle Filter-Based On-Line Crack Propagation Prognosis Method

    PubMed Central

    Chen, Jian; Yuan, Shenfang; Qiu, Lei; Cai, Jian; Yang, Weibo

    2016-01-01

    Prognostics and health management techniques have drawn widespread attention due to their ability to facilitate maintenance activities based on need. On-line prognosis of fatigue crack propagation can offer information for optimizing operation and maintenance strategies in real-time. This paper proposes a Lamb wave-particle filter (LW-PF)-based method for on-line prognosis of fatigue crack propagation which takes advantages of the possibility of on-line monitoring to evaluate the actual crack length and uses a particle filter to deal with the crack evolution and monitoring uncertainties. The piezoelectric transducers (PZTs)-based active Lamb wave method is adopted for on-line crack monitoring. The state space model relating to crack propagation is established by the data-driven and finite element methods. Fatigue experiments performed on hole-edge crack specimens have validated the advantages of the proposed method. PMID:26950130

  10. Research on a Lamb Wave and Particle Filter-Based On-Line Crack Propagation Prognosis Method.

    PubMed

    Chen, Jian; Yuan, Shenfang; Qiu, Lei; Cai, Jian; Yang, Weibo

    2016-03-03

    Prognostics and health management techniques have drawn widespread attention due to their ability to facilitate maintenance activities based on need. On-line prognosis of fatigue crack propagation can offer information for optimizing operation and maintenance strategies in real-time. This paper proposes a Lamb wave-particle filter (LW-PF)-based method for on-line prognosis of fatigue crack propagation which takes advantages of the possibility of on-line monitoring to evaluate the actual crack length and uses a particle filter to deal with the crack evolution and monitoring uncertainties. The piezoelectric transducers (PZTs)-based active Lamb wave method is adopted for on-line crack monitoring. The state space model relating to crack propagation is established by the data-driven and finite element methods. Fatigue experiments performed on hole-edge crack specimens have validated the advantages of the proposed method.

  11. Toward the Application of the Implicit Particle Filter to Real Data in a Shallow Water Model of the Nearshore Ocean

    NASA Astrophysics Data System (ADS)

    Miller, R.

    2015-12-01

    Following the success of the implicit particle filter in twin experiments with a shallow water model of the nearshore environment, the planned next step is application to the intensive Sandy Duck data set, gathered at Duck, NC. Adaptation of the present system to the Sandy Duck data set will require construction and evaluation of error models for both the model and the data, as well as significant modification of the system to allow for the properties of the data set. Successful implementation of the particle filter promises to shed light on the details of the capabilities and limitations of shallow water models of the nearshore ocean relative to more detailed models. Since the shallow water model admits distinct dynamical regimes, reliable parameter estimation will be important. Previous work by other groups give cause for optimism. In this talk I will describe my progress toward implementation of the new system, including problems solved, pitfalls remaining and preliminary results

  12. An iterative particle filter approach for coupled hydro-geophysical inversion of a controlled infiltration experiment

    SciTech Connect

    Manoli, Gabriele; Rossi, Matteo; Pasetto, Damiano; Deiana, Rita; Ferraris, Stefano; Cassiani, Giorgio; Putti, Mario

    2015-02-15

    The modeling of unsaturated groundwater flow is affected by a high degree of uncertainty related to both measurement and model errors. Geophysical methods such as Electrical Resistivity Tomography (ERT) can provide useful indirect information on the hydrological processes occurring in the vadose zone. In this paper, we propose and test an iterated particle filter method to solve the coupled hydrogeophysical inverse problem. We focus on an infiltration test monitored by time-lapse ERT and modeled using Richards equation. The goal is to identify hydrological model parameters from ERT electrical potential measurements. Traditional uncoupled inversion relies on the solution of two sequential inverse problems, the first one applied to the ERT measurements, the second one to Richards equation. This approach does not ensure an accurate quantitative description of the physical state, typically violating mass balance. To avoid one of these two inversions and incorporate in the process more physical simulation constraints, we cast the problem within the framework of a SIR (Sequential Importance Resampling) data assimilation approach that uses a Richards equation solver to model the hydrological dynamics and a forward ERT simulator combined with Archie's law to serve as measurement model. ERT observations are then used to update the state of the system as well as to estimate the model parameters and their posterior distribution. The limitations of the traditional sequential Bayesian approach are investigated and an innovative iterative approach is proposed to estimate the model parameters with high accuracy. The numerical properties of the developed algorithm are verified on both homogeneous and heterogeneous synthetic test cases based on a real-world field experiment.

  13. Hydraulic parameter estimation by remotely-sensed top soil moisture observations with the particle filter

    NASA Astrophysics Data System (ADS)

    Montzka, Carsten; Moradkhani, Hamid; Weihermüller, Lutz; Franssen, Harrie-Jan Hendricks; Canty, Morton; Vereecken, Harry

    2011-03-01

    SummaryIn a synthetic study we explore the potential of using surface soil moisture measurements obtained from different satellite platforms to retrieve soil moisture profiles and soil hydraulic properties using a sequential data assimilation procedure and a 1D mechanistic soil water model. Four different homogeneous soil types were investigated including loamy sand, loam, silt, and clayey soils. The forcing data including precipitation and potential evapotranspiration were taken from the meteorological station of Aachen (Germany). With the aid of the forward model run, a synthetic data set was designed and observations were generated. The virtual top soil moisture observations were then assimilated to update the states and hydraulic parameters of the model by means of a particle filtering data assimilation method. Our analyses include the effect of assimilation strategy, measurement frequency, accuracy in surface soil moisture measurements, and soils differing in textural and hydraulic properties. With this approach we were able to assess the value of periodic spaceborne observations of top soil moisture for soil moisture profile estimation and identify the adequate conditions (e.g. temporal resolution and measurement accuracy) for remotely sensed soil moisture data assimilation. Updating of both hydraulic parameters and state variables allowed better predictions of top soil moisture contents as compared with updating of states only. An important conclusion is that the assimilation of remotely-sensed top soil moisture for soil hydraulic parameter estimation generates a bias depending on the soil type. Results indicate that the ability of a data assimilation system to correct the soil moisture state and estimate hydraulic parameters is driven by the non linearity between soil moisture and pressure head.

  14. An iterative particle filter approach for coupled hydro-geophysical inversion of a controlled infiltration experiment

    NASA Astrophysics Data System (ADS)

    Manoli, Gabriele; Rossi, Matteo; Pasetto, Damiano; Deiana, Rita; Ferraris, Stefano; Cassiani, Giorgio; Putti, Mario

    2015-02-01

    The modeling of unsaturated groundwater flow is affected by a high degree of uncertainty related to both measurement and model errors. Geophysical methods such as Electrical Resistivity Tomography (ERT) can provide useful indirect information on the hydrological processes occurring in the vadose zone. In this paper, we propose and test an iterated particle filter method to solve the coupled hydrogeophysical inverse problem. We focus on an infiltration test monitored by time-lapse ERT and modeled using Richards equation. The goal is to identify hydrological model parameters from ERT electrical potential measurements. Traditional uncoupled inversion relies on the solution of two sequential inverse problems, the first one applied to the ERT measurements, the second one to Richards equation. This approach does not ensure an accurate quantitative description of the physical state, typically violating mass balance. To avoid one of these two inversions and incorporate in the process more physical simulation constraints, we cast the problem within the framework of a SIR (Sequential Importance Resampling) data assimilation approach that uses a Richards equation solver to model the hydrological dynamics and a forward ERT simulator combined with Archie's law to serve as measurement model. ERT observations are then used to update the state of the system as well as to estimate the model parameters and their posterior distribution. The limitations of the traditional sequential Bayesian approach are investigated and an innovative iterative approach is proposed to estimate the model parameters with high accuracy. The numerical properties of the developed algorithm are verified on both homogeneous and heterogeneous synthetic test cases based on a real-world field experiment.

  15. Removal of Particles and Acid Gases (SO2 or HCl) with a Ceramic Filter by Addition of Dry Sorbents

    SciTech Connect

    Hemmer, G.; Kasper, G.; Wang, J.; Schaub, G.

    2002-09-20

    The present investigation intends to add to the fundamental process design know-how for dry flue gas cleaning, especially with respect to process flexibility, in cases where variations in the type of fuel and thus in concentration of contaminants in the flue gas require optimization of operating conditions. In particular, temperature effects of the physical and chemical processes occurring simultaneously in the gas-particle dispersion and in the filter cake/filter medium are investigated in order to improve the predictive capabilities for identifying optimum operating conditions. Sodium bicarbonate (NaHCO{sub 3}) and calcium hydroxide (Ca(OH){sub 2}) are known as efficient sorbents for neutralizing acid flue gas components such as HCl, HF, and SO{sub 2}. According to their physical properties (e.g. porosity, pore size) and chemical behavior (e.g. thermal decomposition, reactivity for gas-solid reactions), optimum conditions for their application vary widely. The results presented concentrate on the development of quantitative data for filtration stability and overall removal efficiency as affected by operating temperature. Experiments were performed in a small pilot unit with a ceramic filter disk of the type Dia-Schumalith 10-20 (Fig. 1, described in more detail in Hemmer 2002 and Hemmer et al. 1999), using model flue gases containing SO{sub 2} and HCl, flyash from wood bark combustion, and NaHCO{sub 3} as well as Ca(OH){sub 2} as sorbent material (particle size d{sub 50}/d{sub 84} : 35/192 {micro}m, and 3.5/16, respectively). The pilot unit consists of an entrained flow reactor (gas duct) representing the raw gas volume of a filter house and the filter disk with a filter cake, operating continuously, simulating filter cake build-up and cleaning of the filter medium by jet pulse. Temperatures varied from 200 to 600 C, sorbent stoichiometric ratios from zero to 2, inlet concentrations were on the order of 500 to 700 mg/m{sup 3}, water vapor contents ranged from

  16. Variational filtering.

    PubMed

    Friston, K J

    2008-07-01

    This note presents a simple Bayesian filtering scheme, using variational calculus, for inference on the hidden states of dynamic systems. Variational filtering is a stochastic scheme that propagates particles over a changing variational energy landscape, such that their sample density approximates the conditional density of hidden and states and inputs. The key innovation, on which variational filtering rests, is a formulation in generalised coordinates of motion. This renders the scheme much simpler and more versatile than existing approaches, such as those based on particle filtering. We demonstrate variational filtering using simulated and real data from hemodynamic systems studied in neuroimaging and provide comparative evaluations using particle filtering and the fixed-form homologue of variational filtering, namely dynamic expectation maximisation.

  17. Particle Pusher for the Investigation of Wave-Particle Interactions in the Magnetic Centrifugal Mass Filter (MCMF)

    NASA Astrophysics Data System (ADS)

    Kulp-McDowall, Taylor; Ochs, Ian; Fisch, Nathaniel

    2016-10-01

    A particle pusher was constructed in MATLAB using a fourth order Runge-Kutta algorithm to investigate the wave-particle interactions within theoretical models of the MCMF. The model simplified to a radial electric field and a magnetic field focused in the z direction. Studies on an average velocity calculation were conducted in order to test the program's behavior in the large radius limit. The results verified that the particle pusher was behaving correctly. Waves were then simulated on the rotating particles with a periodic divergenceless perturbation in the Bz component of the magnetic field. Preliminary runs indicate an agreement of the particle's motion with analytical predictions-ie. cyclic contractions of the doubly rotating particle's gyroradius.The next stage of the project involves the implementation of particle collisions and turbulence within the particle pusher in order to increase its accuracy and applicability. This will allow for a further investigation of the alpha channeling electrode replacement thesis first proposed by Abraham Fetterman in 2011. Made possible by Grants from the Princeton Environmental Institute (PEI) and the Program for Plasma Science and Technology (PPST).

  18. The performance of biological anaerobic filters packed with sludge-fly ash ceramic particles (SFCP) and commercial ceramic particles (CCP) during the restart period: effect of the C/N ratios and filter media.

    PubMed

    Yue, Qinyan; Han, Shuxin; Yue, Min; Gao, Baoyu; Li, Qian; Yu, Hui; Zhao, Yaqin; Qi, Yuanfeng

    2009-11-01

    Two lab-scale upflow biological anaerobic filters (BAF) packed with sludge-fly ash ceramic particles (SFCP) and commercial ceramic particles (CCP) were employed to investigate effects of the C/N ratios and filter media on the BAF performance during the restart period. The results indicated that BAF could be restarted normally after one-month cease. The C/N ratio of 4.0 was the thresholds of nitrate removal and nitrite accumulation. TN removal and phosphate uptake reached the maximum value at the same C/N ratio of 5.5. Ammonia formation was also found and excreted a negative influence on TN removal, especially when higher C/N ratios were applied. Nutrients were mainly degraded within the height of 25 cm from the bottom. In addition, SFCP, as novel filter media manufactured by wastes-dewatered sludge and fly ash, represented a better potential in inhibiting nitrite accumulation, TN removal and phosphate uptake due to their special characteristics in comparison with CCP.

  19. The impact of filtering direct-feedthrough on the x-space theory of magnetic particle imaging

    NASA Astrophysics Data System (ADS)

    Lu, Kuan; Goodwill, Patrick; Zheng, Bo; Conolly, Steven

    2011-03-01

    Magnetic particle imaging (MPI) is a new medical imaging modality that maps the instantaneous response of superparamagnetic particles under an applied magnetic field. In MPI, the excitation and detection of the nanoparticles occur simultaneously. Therefore, when a sinusoidal excitation field is applied to the system, the received signal spectrum contains both harmonics from the particles and a direct feedthrough signal from the source at the fundamental drive frequency. Removal of the induced feedthrough signal from the received signal requires significant filtering, which also removes part of the signal spectrum. In this paper, we present a method to investigate the impact of temporally filtering out individual lower order harmonics on the reconstructed x-space image. Analytic and simulation results show that the loss of particle signal at low frequency leads to a recoverable loss of low spatial frequency information in the x-space image. Initial experiments validate the findings and demonstrate the feasibility of the recovery of the lost signal. This builds on earlier work that discusses the ideal one-dimensional MPI system and harmonic decomposition of the MPI signal.

  20. A comparison of biologically active filters for the removal of ozone by-products, turbidity, and particles

    SciTech Connect

    Coffey, B.M.; Krasner, S.W.; Sclimenti, M.J.; Hacker, P.A.; Gramith, J.T.

    1996-11-01

    Biofiltration tests were performed at the Metropolitan Water District of Southern California`s 5.5-mgd (21,000 m{sup 3}d) demonstration plant using two 400 ft{sup 2} (37 m{sup 2}) anthracite/sand filters and a 6 ft{sup 2} (0.56 m{sup 2}) granular activated carbon (GAC)/sand filter operated in parallel. The empty-bed contact time (EBCT) within the GAC and anthracite ranged from 2.1-3.1 min. The filters were evaluated based on (1) conventional filtration performance (turbidity, particle removal, and headloss); (2) removal of biodegradable ozone by-products (assimilable organic carbon [AOC], aldehydes, and aldoketoacids) after startup; (3) removal of biodegradable ozone by-products at steady state; and (4) resistance to short-term process upsets such as intermittent chlorination or filter out-of-service time. Approximately 80 percent formaldehyde removal was achieved by the anthracite/sand filter operated at a 2.1-min EBCT (6 gpm/ft{sup 2} [15 m/h]) within 8 days of ozone operation. The GAC/sand filter operated at the same rate achieved 80 percent removal within 1 day, possibly as an additive effect of adsorption and biological removal. In-depth aldehyde monitoring at four depths (0.5-min EBCT intervals) provided additional insight into the removal kinetics. During periods of warmer water temperature, from 20 to 48 percent of the AOC was removed in the flocculation/sedimentation basins by 40-75 percent. This percentage removal typically resulted in AOC concentrations within 40 {mu}g C/L of the raw, unozonated water levels.

  1. Combined processes of two-stage Fenton-biological anaerobic filter-biological aerated filter for advanced treatment of landfill leachate.

    PubMed

    Wang, Xiaojun; Han, Jijun; Chen, Zhiwei; Jian, Lei; Gu, Xiaoyang; Lin, Che-Jen

    2012-12-01

    There are numerous non-biodegradable organic materials in the mature landfill leachate. To meet the new discharge standard of China, additional advanced treatment is needed for the effluent from the biological treatment processes of leachate. In this study, a combined process including two stages of "Fenton-biological anaerobic filter (BANF)-biological aerated filter (BAF)" was evaluated to address the advanced treatment need. The Fenton oxidation was applied to reduce chemical oxygen demand (COD) and enhance biodegradability of refractory organics, and the BANF-BAF process was then applied to remove the total nitrogen (TN). The treatment achieved effluent concentrations of COD<70 mg/L, TN<40 mg/L and NH(3)-N<10 mg/L. The removal efficiency of COD and TN were 96.1% and 95.9%, respectively. The effluent quality met the new discharge standard for Pollution Control on the Landfill Site of Municipal Solid of PR China (GB16889-2008). The operation cost of these processes was about 36.1CHY/t (5.70USD/t).

  2. Decentralized Riemannian Particle Filtering with Applications to Multi-Agent Localization

    DTIC Science & Technology

    2012-06-14

    USA, December 10-12 1997. 172 52. Brown, Robert G. and Patrick Y.C. Hwang. Introduction To Random Signals and Applied Kalman Filtering. John Wiley...London, 1994. 234. Randal Beard, Jonathan Lawton Wynn Stirling , Jacob Gunther. “Nonlinear Projec- tion Filter based on Galerkin Approximation”. AIAA...Sensor Networks and Information Processing, 161 – 166. 2004. 242. Roberts , S. Reece S. “Robust, Low-Bandwidth, Multi-Vehicle Mapping”. in Pro

  3. Advanced Concepts in Distortion-Invariant Phase-Only Filter Design

    DTIC Science & Technology

    1992-07-01

    State Sciences Electromagnetics & Reliability Directorate If your address has changed or if you -vish to be removed from the Rome Laboratory ,nailing...saturation level. (We will say that a filter is which the filter magnitude is nonzero) for these optimal saturated if magnitude limitations have changed the...drive more of their area into satura- tion In those actions the spectral shape of the filter is f S(f)H(f)d changed , with an adverse effect on the SNR if

  4. MODELING REFLECTANCE AND TRANSMITTANCE OF QUARTZ-FIBER FILTER SAMPLES CONTAINING ELEMENTAL CARBON PARTICLES: IMPLICATIONS FOR THERMAL/OPTICAL ANALYSIS. (R831086)

    EPA Science Inventory

    A radiative transfer scheme that considers absorption, scattering, and distribution of light-absorbing elemental carbon (EC) particles collected on a quartz-fiber filter was developed to explain simultaneous filter reflectance and transmittance observations prior to and during...

  5. Three dimensional indoor positioning based on visible light with Gaussian mixture sigma-point particle filter technique

    NASA Astrophysics Data System (ADS)

    Gu, Wenjun; Zhang, Weizhi; Wang, Jin; Amini Kashani, M. R.; Kavehrad, Mohsen

    2015-01-01

    Over the past decade, location based services (LBS) have found their wide applications in indoor environments, such as large shopping malls, hospitals, warehouses, airports, etc. Current technologies provide wide choices of available solutions, which include Radio-frequency identification (RFID), Ultra wideband (UWB), wireless local area network (WLAN) and Bluetooth. With the rapid development of light-emitting-diodes (LED) technology, visible light communications (VLC) also bring a practical approach to LBS. As visible light has a better immunity against multipath effect than radio waves, higher positioning accuracy is achieved. LEDs are utilized both for illumination and positioning purpose to realize relatively lower infrastructure cost. In this paper, an indoor positioning system using VLC is proposed, with LEDs as transmitters and photo diodes as receivers. The algorithm for estimation is based on received-signalstrength (RSS) information collected from photo diodes and trilateration technique. By appropriately making use of the characteristics of receiver movements and the property of trilateration, estimation on three-dimensional (3-D) coordinates is attained. Filtering technique is applied to enable tracking capability of the algorithm, and a higher accuracy is reached compare to raw estimates. Gaussian mixture Sigma-point particle filter (GM-SPPF) is proposed for this 3-D system, which introduces the notion of Gaussian Mixture Model (GMM). The number of particles in the filter is reduced by approximating the probability distribution with Gaussian components.

  6. Preliminary study on filamentous particle distribution in septic tank effluent and their impact on filter cake development.

    PubMed

    Spychała, Marcin; Nieć, Jakub; Pawlak, Maciej

    2013-01-01

    In this paper, the preliminary study on the impact of filamentous particles (FP) in the septic tank effluent (STE) on filter cake (FC) development was presented. The number, length and diameter (30 p./cm3, 451 and 121 microm, respectively, on average) of FPs were measured using microscope image analysis of STE samples condensed using a vacuum evaporation set. Results of this study showed, that 0.73% of volatile suspended solids (VSSs) mass from the STE occurs in the form of FPs. No correlation between FP total mass and VSS was found. An experiment with a layer of FPs simulated by ground toilet paper was conducted and showed the impact of this layer (4.89 mg/cm2) on wastewater hydraulic conductivity--for an FC with FPs (FC-FP), hydraulic conductivity was seven times lower than for the FC without the FP layer, and on outflow quality (lower concentration of organic matter expressed as chemical oxygen demand (COD) in effluent from the FC-FP filter than in the effluent from the FC filter: 618 and 732 gO2/m3, respectively). Despite a relatively small amount of FPs in STE solids (as volume fraction), they play an important role in FC development due to their relatively high length and low degradability. Probably relatively small pores of the FC containing FPs (FC-FP) caused a small particle blocking and a decrease in permeability.

  7. Advanced astronomical filter design: challenges, strategy, and results to meet current and future requirements

    NASA Astrophysics Data System (ADS)

    Reichel, S.; Biertümpfel, R.; Brauneck, U.; Bourquin, S.; Marín-Franch, A.

    2016-07-01

    The Observatorio Astrofisico de Javalambre in Spain will conduct an all-sky astronomical survey using multi-bands, where optical filters are needed. These filters are narrow bandpass steep edge filters (FWHM = 14.5 nm) in a spectrum between 390 to 920 nm with 10.0 nm steps. In order to fulfill the demanding requirements for final scientific image quality and transmitted wavefront error a new white-light Shack Hartmann sensor and difficult refractive index measurements of the sub-assembly were needed. In addition due to the spectral requirements the design and manufacturing of the filters were pushed at its technological limit.

  8. New ion-assisted filtered cathodic arc deposition (IFCAD) technology for producing advanced thin films on temperature-sensitive substrates

    NASA Astrophysics Data System (ADS)

    Fulton, Michael L.

    1999-10-01

    An innovative Ion-Assisted Filtered Cathodic Arc Deposition (IFCAD) system has been developed for low temperature production of thin-film coatings. The IFCAD system employs electro-magnetic and mechanical filtering techniques to remove unwanted macroparticles and neutral atoms from the plasma stream. Therefore, only ions within a defined energy range arrive at the substrate surface, depositing thin-films with excellent mechanical and optical properties. Ion- Assisted-Deposition is coupled with Filtered Cathodic Arc technology to enhance and modify the arc deposited thin- films. Using an advanced computer controlled plasma beam scanning system, high quality, large area, uniform IFCAD multi-layer film structures are attained. Amorphous Diamond- Like-Carbon films (up to 85% sp3 bonded carbon; and micro- hardness greater than 50 GPa) have been deposited in multi- layer thin-film combinations with other IFCAD source materials (such as: Al2O3) for optical and tribological applications. Rutile TiO2 (refractive index of 2.8 at 500 nm) has been deposited with this technology for advanced optical filter applications. The new IFCAD technology has been included in development programs, such as: plastic and glass lens coatings for optical systems; wear resistant coatings on various metal substrates, ultra smooth, durable, surface hydrophobic coatings for aircraft windows; EUV coatings for space instrumentation; transparent conductive coatings; and UV protective coatings for solar cell concentrator plastic Fresnel lens elements for space power.

  9. Advanced Scavenge Systems for an Integrated Engine Inlet Particle Separator

    DTIC Science & Technology

    1977-09-01

    INSTRUMENTAT10N............ .oooo.....& 117 TEST RIG FACILITY INSTALLAT ION ..................... 124 TEST PLA.N OUJTLINE. . ... . .. .. .. .. . ... IZ...CDD 40 - 00 COD 0 cc 0a co 0 im 0 00 0-4 < -i 4L B LA SECT ION I (HUB) I1- SECTION 2 2- SECTION 3 3- SECTION 4 4 SECTION 5 5 STACKING POINT L.o in...based on previous particle seoarator experienc*, the difference in separation ef~iciency from 20-percent scavenge to 25 percent scavenge is mall, and

  10. Advanced Handling and Sorting Techniques for Ultrasmall Particles

    DTIC Science & Technology

    1975-04-15

    Nitrogen Mixtures III-ll Ashing of Inorganic Materials with Oxygen, Hydrogen and Tetrafluoromethane 111-19 Spread in a Particle Beam Diameter IV-14...MATERIALS WITH OXYGEN, HYDROGEN AND TETRAFLUOROMETHANE Sample Material Initial Wt gm Final Wt. gm % Residue A. Ashed with Oxygen 1. Clay... Tetrafluoromethane (CF4) 1. Silica Dust 2. Uranium Dioxide 0.5173 1.4142 1.1845 93.2 4.0943 73.4 0.5601 99.9 4.1506 100.0 0.3409 60.8 2.9834 100.0 0.6301

  11. Nanoparticle filtration performance of NIOSH-certified particulate air-purifying filtering facepiece respirators: evaluation by light scattering photometric and particle number-based test methods.

    PubMed

    Rengasamy, Samy; Eimer, Benjamin C

    2012-01-01

    National Institute for Occupational Safety and Health (NIOSH) certification test methods employ charge neutralized NaCl or dioctyl phthalate (DOP) aerosols to measure filter penetration levels of air-purifying particulate respirators photometrically using a TSI 8130 automated filter tester at 85 L/min. A previous study in our laboratory found that widely different filter penetration levels were measured for nanoparticles depending on whether a particle number (count)-based detector or a photometric detector was used. The purpose of this study was to better understand the influence of key test parameters, including filter media type, challenge aerosol size range, and detector system. Initial penetration levels for 17 models of NIOSH-approved N-, R-, and P-series filtering facepiece respirators were measured using the TSI 8130 photometric method and compared with the particle number-based penetration (obtained using two ultrafine condensation particle counters) for the same challenge aerosols generated by the TSI 8130. In general, the penetration obtained by the photometric method was less than the penetration obtained with the number-based method. Filter penetration was also measured for ambient room aerosols. Penetration measured by the TSI 8130 photometric method was lower than the number-based ambient aerosol penetration values. Number-based monodisperse NaCl aerosol penetration measurements showed that the most penetrating particle size was in the 50 nm range for all respirator models tested, with the exception of one model at ~200 nm size. Respirator models containing electrostatic filter media also showed lower penetration values with the TSI 8130 photometric method than the number-based penetration obtained for the most penetrating monodisperse particles. Results suggest that to provide a more challenging respirator filter test method than what is currently used for respirators containing electrostatic media, the test method should utilize a sufficient number

  12. Numerical experiments with an implicit particle filter for the shallow water equations

    NASA Astrophysics Data System (ADS)

    Souopgui, I.; Chorin, A. J.; Hussaini, M.

    2012-12-01

    of the state space. In our numerical experiments, we varied the availability of the data (in both space and time) as well as the variance of the observation noise. We found that the implicit particle filter is reliable and efficient in all scenarios we considered. The implicit sampling method could improve the accuracy of the traditional variational approach. Moreover, we obtain quantitative measures of the uncertainty of the state estimate ``for free,'' while no information about the uncertainty is easily available using the traditional 4D-Var method only.

  13. Effects of Particle Filters and Selective Catalytic Reduction on Heavy-Duty Diesel Drayage Truck Emissions at the Port of Oakland.

    PubMed

    Preble, Chelsea V; Dallmann, Timothy R; Kreisberg, Nathan M; Hering, Susanne V; Harley, Robert A; Kirchstetter, Thomas W

    2015-07-21

    Effects of fleet modernization and use of diesel particle filters (DPF) and selective catalytic reduction (SCR) on heavy-duty diesel truck emissions were studied at the Port of Oakland in California. Nitrogen oxides (NOx), black carbon (BC), particle number (PN), and size distributions were measured in the exhaust plumes of ∼1400 drayage trucks. Average NOx, BC, and PN emission factors for newer engines (2010-2013 model years) equipped with both DPF and SCR were 69 ± 15%, 92 ± 32%, and 66 ± 35% lower, respectively, than 2004-2006 engines without these technologies. Intentional oxidation of NO to NO2 for DPF regeneration increased tailpipe NO2 emissions, especially from older (1994-2006) engines with retrofit DPFs. Increased deployment of advanced controls has further skewed emission factor distributions; a small number of trucks emit a disproportionately large fraction of total BC and NOx. The fraction of DPF-equipped drayage trucks increased from 2 to 99% and the median engine age decreased from 11 to 6 years between 2009 and 2013. Over this period, fleet-average BC and NOx emission factors decreased by 76 ± 22% and 53 ± 8%, respectively. Emission changes occurred rapidly compared to what would have been observed due to natural (i.e., unforced) turnover of the Port truck fleet. These results provide a preview of more widespread emission changes expected statewide and nationally in the coming years.

  14. Impacts of backwashing on granular activated carbon filters for advanced wastewater treatment.

    PubMed

    Frank, Joshua; Ruhl, Aki Sebastian; Jekel, Martin

    2015-12-15

    The use of granular activated carbon (GAC) in fixed bed filters is a promising option for the removal of organic micropollutants (OMP) from wastewater treatment plant effluents. Frequent backwashing of the filter bed is inevitable, but its effect on potential filter stratification is not well understood yet and thus has been evaluated in the present study for two commercial GAC products. Backwashing of GAC filters was simulated with 10 or 100 filter bed expansions of 20 or 100% at backwash velocities of 12 and 40 m/h, respectively. Five vertical fractions were extracted and revealed a vertical stratification according to grain sizes and material densities. Sieve analyses indicated increasing grain sizes towards the bottom for one GAC while grain sizes of the other GAC were more homogeneously distributed throughout the filter bed. The apparent densities of the top sections were significantly lower than that of the bottom sections of both products. Comparative long term fixed bed adsorption experiments with the top and bottom sections of the stratified GAC showed remarkable differences in breakthrough curves of dissolved organic carbon, UV light absorption at 254 nm wavelength (UVA254) and OMP. GAC from the upper section showed constantly better removal efficiencies than GAC from the bottom section, especially for weakly adsorbing OMP such as sulfamethoxazole. Furthermore correlations between UVA254 reductions and OMP removals were found.

  15. Far Ultraviolet Refractive Index of Optical Materials for Solar Blind Channel (SBC) Filters for HST Advanced Camera for Surveys

    NASA Technical Reports Server (NTRS)

    Leviton, Douglas B.; Madison, Timothy J.; Petrone, Peter

    1998-01-01

    Refractive index measurements using the minimum deviation method have been carried out for prisms of a variety of far ultraviolet optical materials used in the manufacture of Solar Blind Channel (SBC) filters for the HST Advanced Camera for Surveys (ACS). Some of the materials measured are gaining popularity in a variety of high technology applications including high power excimer lasers and advanced microlithography optics operating in a wavelength region where high quality knowledge of optical material properties is sparse. Our measurements are of unusually high accuracy and precision for this wavelength region owing to advanced instrumentation in the large vacuum chamber of the Diffraction Grating Evaluation Facility (DGEF) at Goddard Space Flight Center (GSFC). Index values for CaF2, BaF2, LiF, and far ultraviolet grades of synthetic sapphire and synthetic fused silica are reported and compared with values from the literature.

  16. Innovative experimental particle physics through technological advances: Past, present and future

    SciTech Connect

    Cheung, Harry W.K.; /Fermilab

    2005-01-01

    This mini-course gives an introduction to the techniques used in experimental particle physics with an emphasis on the impact of technological advances. The basic detector types and particle accelerator facilities will be briefly covered with examples of their use and with comparisons. The mini-course ends with what can be expected in the near future from current technology advances. The mini-course is intended for graduate students and post-docs and as an introduction to experimental techniques for theorists.

  17. Design and physicochemical characterization of advanced spray-dried tacrolimus multifunctional particles for inhalation

    PubMed Central

    Wu, Xiao; Hayes, Don; Zwischenberger, Joseph B; Kuhn, Robert J; Mansour, Heidi M

    2013-01-01

    The aim of this study was to design, develop, and optimize respirable tacrolimus microparticles and nanoparticles and multifunctional tacrolimus lung surfactant mimic particles for targeted dry powder inhalation delivery as a pulmonary nanomedicine. Particles were rationally designed and produced at different pump rates by advanced spray-drying particle engineering design from organic solution in closed mode. In addition, multifunctional tacrolimus lung surfactant mimic dry powder particles were prepared by co-dissolving tacrolimus and lung surfactant mimic phospholipids in methanol, followed by advanced co-spray-drying particle engineering design technology in closed mode. The lung surfactant mimic phospholipids were 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and 1,2-dipalmitoyl-sn-glycero-3-[phosphor-rac-1-glycerol]. Laser diffraction particle sizing indicated that the particle size distributions were suitable for pulmonary delivery, whereas scanning electron microscopy imaging indicated that these particles had both optimal particle morphology and surface morphology. Increasing the pump rate percent of tacrolimus solution resulted in a larger particle size. X-ray powder diffraction patterns and differential scanning calorimetry thermograms indicated that spray drying produced particles with higher amounts of amorphous phase. X-ray powder diffraction and differential scanning calorimetry also confirmed the preservation of the phospholipid bilayer structure in the solid state for all engineered respirable particles. Furthermore, it was observed in hot-stage micrographs that raw tacrolimus displayed a liquid crystal transition following the main phase transition, which is consistent with its interfacial properties. Water vapor uptake and lyotropic phase transitions in the solid state at varying levels of relative humidity were determined by gravimetric vapor sorption technique. Water content in the various powders was very low and well within the levels necessary

  18. The Los Alamos Laser Acceleration of Particles Workshop and beginning of the advanced accelerator concepts field

    NASA Astrophysics Data System (ADS)

    Joshi, C.

    2012-12-01

    The first Advanced Acceleration of Particles-AAC-Workshop (actually named Laser Acceleration of Particles Workshop) was held at Los Alamos in January 1982. The workshop lasted a week and divided all the acceleration techniques into four categories: near field, far field, media, and vacuum. Basic theorems of particle acceleration were postulated (later proven) and specific experiments based on the four categories were formulated. This landmark workshop led to the formation of the advanced accelerator R&D program in the HEP office of the DOE that supports advanced accelerator research to this day. Two major new user facilities at Argonne and Brookhaven and several more directed experimental efforts were built to explore the advanced particle acceleration schemes. It is not an exaggeration to say that the intellectual breadth and excitement provided by the many groups who entered this new field provided the needed vitality to then recently formed APS Division of Beams and the new online journal Physical Review Special Topics-Accelerators and Beams. On this 30th anniversary of the AAC Workshops, it is worthwhile to look back at the legacy of the first Workshop at Los Alamos and the fine groundwork it laid for the field of advanced accelerator concepts that continues to flourish to this day.

  19. Adaptive prognosis of lithium-ion batteries based on the combination of particle filters and radial basis function neural networks

    NASA Astrophysics Data System (ADS)

    Sbarufatti, Claudio; Corbetta, Matteo; Giglio, Marco; Cadini, Francesco

    2017-03-01

    Lithium-Ion rechargeable batteries are widespread power sources with applications to consumer electronics, electrical vehicles, unmanned aerial and spatial vehicles, etc. The failure to supply the required power levels may lead to severe safety and economical consequences. Thus, in view of the implementation of adequate maintenance strategies, the development of diagnostic and prognostic tools for monitoring the state of health of the batteries and predicting their remaining useful life is becoming a crucial task. Here, we propose a method for predicting the end of discharge of Li-Ion batteries, which stems from the combination of particle filters with radial basis function neural networks. The major innovation lies in the fact that the radial basis function model is adaptively trained on-line, i.e., its parameters are identified in real time by the particle filter as new observations of the battery terminal voltage become available. By doing so, the prognostic algorithm achieves the flexibility needed to provide sound end-of-discharge time predictions as the charge-discharge cycles progress, even in presence of anomalous behaviors due to failures or unforeseen operating conditions. The method is demonstrated with reference to actual Li-Ion battery discharge data contained in the prognostics data repository of the NASA Ames Research Center database.

  20. Apparatus and method for concentrating and filtering particles suspended in a fluid

    DOEpatents

    Fiechtner, Gregory J.; Cummings, Eric B.; Singh, Anup K.

    2009-05-19

    Disclosed is a device for separating and concentrating particles suspended in a fluid stream by using dielectrophoresis (DEP) to trap and/or deflect those particles as they migrate through a fluid channel. The method uses fluid channels designed to constrain a liquid flowing through it to uniform electrokinetic flow velocities. This behavior is achieved by connecting deep and shallow sections of channels, with the channel depth varying abruptly along an interface. By careful design of abrupt changes in specific permeability at the interface, an abrupt and spatially uniform change in electrokinetic force can be selected. Because these abrupt interfaces also cause a sharp gradient in applied electric fields, a DEP force also can be established along the interface. Depending on the complex conductivity of the suspended particles and the immersion liquid, the DEP force can controllably complement or oppose the local electrokinetic force transporting the fluid through the channel allowing for manipulation of particles suspended in the transporting liquid.

  1. Advanced fluorescence imaging endoscopy using an acousto-optic tuneable filter

    NASA Astrophysics Data System (ADS)

    Whelan, Maurice P.; Bouhifd, Mounir; Aprahamian, Marc

    2004-07-01

    Two novel prototype instruments for in vivo fluorescence-based medical diagnostics are described. The devices are based on an acousto-optic tuneable filter (AOTF) and can be easily attached to the eyepiece of most commercially available endoscopes. The instruments developed offer significant advantages over typical fixed-filter or filter-wheel fluorescence imaging systems in terms of flexibility, performance and diagnostic potential. Any filtering center-wavelength in the range from 450 to 700 nm can be rapidly selected either by random access or sequential tuning using simple commands delivered over a PC serial interface. In addition, both filtered and unfiltered light can be imaged to facilitate the direct association of fluorescence signals with specific anatomical sites. To demonstrate the system in vivo, a study of the diagnostic potential of fluorescence imaging for pancreatitis was conducted on rats. The aim was to detect extremely low-levels of endogenous protoporphyrin IX (PpIX) that has been shown to accumulate in early-stage diseased tissue undergoing an inflammatory response. Results show clearly that the device is effective in diagnosing mild pancreatitis in rats without the necessity of administering PpIX promoting agents such as ALA. Planning of human clinical trials is currently underway to demonstrate its potential as a tool for non-invasive early diagnosis of gastroenterological diseases.

  2. Technical note: Improving the AWAT filter with interpolation schemes for advanced processing of high resolution data

    NASA Astrophysics Data System (ADS)

    Peters, Andre; Nehls, Thomas; Wessolek, Gerd

    2016-06-01

    Weighing lysimeters with appropriate data filtering yield the most precise and unbiased information for precipitation (P) and evapotranspiration (ET). A recently introduced filter scheme for such data is the AWAT (Adaptive Window and Adaptive Threshold) filter (Peters et al., 2014). The filter applies an adaptive threshold to separate significant from insignificant mass changes, guaranteeing that P and ET are not overestimated, and uses a step interpolation between the significant mass changes. In this contribution we show that the step interpolation scheme, which reflects the resolution of the measuring system, can lead to unrealistic prediction of P and ET, especially if they are required in high temporal resolution. We introduce linear and spline interpolation schemes to overcome these problems. To guarantee that medium to strong precipitation events abruptly following low or zero fluxes are not smoothed in an unfavourable way, a simple heuristic selection criterion is used, which attributes such precipitations to the step interpolation. The three interpolation schemes (step, linear and spline) are tested and compared using a data set from a grass-reference lysimeter with 1 min resolution, ranging from 1 January to 5 August 2014. The selected output resolutions for P and ET prediction are 1 day, 1 h and 10 min. As expected, the step scheme yielded reasonable flux rates only for a resolution of 1 day, whereas the other two schemes are well able to yield reasonable results for any resolution. The spline scheme returned slightly better results than the linear scheme concerning the differences between filtered values and raw data. Moreover, this scheme allows continuous differentiability of filtered data so that any output resolution for the fluxes is sound. Since computational burden is not problematic for any of the interpolation schemes, we suggest always using the spline scheme.

  3. Modulation power of porous materials and usage as ripple filter in particle therapy.

    PubMed

    Printz Ringbæk, Toke; Simeonov, Yuri; Witt, Matthias; Engenhart-Cabillic, Rita; Kraft, Gerhard; Zink, Klemens; Weber, Uli

    2017-04-07

    Porous materials with microscopic structures like foam, sponges, lung tissues and lung substitute materials have particular characteristics, which differ from those of solid materials. Ion beams passing through porous materials show much stronger energy straggling than expected for non-porous solid materials of the same thickness. This effect depends on the microscopic fine structure, the density and the thickness of the porous material. The beam-modulating effect from a porous plate enlarges the Bragg peak, yielding similar benefits in irradiation time reduction as a ripple filter. A porous plate can additionally function as a range shifter, which since a higher energy can be selected for the same penetration depth in the body reduces the scattering at the beam line and therefore improves the lateral fall-off. Bragg curve measurements of ion beams passing through different porous materials have been performed in order to determine the beam modulation effect of each. A mathematical model describing the correlation between the mean material density, the porous pore structure size and the strength of the modulation has been developed and a new material parameter called 'modulation power' is defined as the square of the Gaussian sigma divided by the mean water-equivalent thickness of the porous absorber. Monte Carlo simulations have been performed in order to validate the model and to investigate the Bragg peak enlargement, the scattering effects of porosity and the lateral beam width at the end of the beam range. The porosity is found to only influence the lateral scattering in a negligible way. As an example of a practical application, it is found that a 20 mm and 50 mm plate of Gammex LN300 performs similar to a 3 mm and 6 mm ripple filter, respectively, and at the same time can improve the sharpness of the lateral beam due to its multifunctionality as a ripple filter and a range shifter.

  4. Modulation power of porous materials and usage as ripple filter in particle therapy

    NASA Astrophysics Data System (ADS)

    Printz Ringbæk, Toke; Simeonov, Yuri; Witt, Matthias; Engenhart-Cabillic, Rita; Kraft, Gerhard; Zink, Klemens; Weber, Uli

    2017-04-01

    Porous materials with microscopic structures like foam, sponges, lung tissues and lung substitute materials have particular characteristics, which differ from those of solid materials. Ion beams passing through porous materials show much stronger energy straggling than expected for non-porous solid materials of the same thickness. This effect depends on the microscopic fine structure, the density and the thickness of the porous material. The beam-modulating effect from a porous plate enlarges the Bragg peak, yielding similar benefits in irradiation time reduction as a ripple filter. A porous plate can additionally function as a range shifter, which since a higher energy can be selected for the same penetration depth in the body reduces the scattering at the beam line and therefore improves the lateral fall-off. Bragg curve measurements of ion beams passing through different porous materials have been performed in order to determine the beam modulation effect of each. A mathematical model describing the correlation between the mean material density, the porous pore structure size and the strength of the modulation has been developed and a new material parameter called ‘modulation power’ is defined as the square of the Gaussian sigma divided by the mean water-equivalent thickness of the porous absorber. Monte Carlo simulations have been performed in order to validate the model and to investigate the Bragg peak enlargement, the scattering effects of porosity and the lateral beam width at the end of the beam range. The porosity is found to only influence the lateral scattering in a negligible way. As an example of a practical application, it is found that a 20 mm and 50 mm plate of Gammex LN300 performs similar to a 3 mm and 6 mm ripple filter, respectively, and at the same time can improve the sharpness of the lateral beam due to its multifunctionality as a ripple filter and a range shifter.

  5. Denuder/filter sampling of organic acids and organosulfates at urban and boreal forest sites: Gas/particle distribution and possible sampling artifacts

    NASA Astrophysics Data System (ADS)

    Kristensen, Kasper; Bilde, Merete; Aalto, Pasi P.; Petäjä, Tuukka; Glasius, Marianne

    2016-04-01

    Carboxylic acids and organosulfates comprise an important fraction of atmospheric secondary organic aerosols formed from both anthropogenic and biogenic precursors. The partitioning of these compounds between the gas and particle phase is still unclear and further research is warranted to better understand the abundance and effect of organic acids and organosulfates on the formation and properties of atmospheric aerosols. This work compares atmospheric aerosols collected at an urban and a boreal forest site using two side-by-side sampling systems; a high volume sampler (HVS) and a low volume (LVS) denuder/filter sampling system allowing for separate collection of gas- and particle-phase organics. All particle filters and denuder samples were collected at H.C. Andersen Boulevard (HCAB), Copenhagen, Denmark in the summer of 2010, and at the remote boreal forest site at Hyytiälä forestry field station in Finland in the summer of 2012. The chemical composition of gas- and particle-phase secondary organic aerosol was investigated by ultra-high performance liquid chromatography/electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC/ESI-Q-TOFMS), with a focus on carboxylic acids and organosulfates. Results show gas-phase concentrations higher than those observed in the particle phase by a factor of 5-6 in HCAB 2010 and 50-80 in Hyytiälä 2012. Although abundant in the particle phase, no organosulfates were detected in the gas phase at either site. Through a comparison of samples collected by the HVS and the LVS denuder/filter sampling system we evaluate the potential artifacts associated with sampling of atmospheric aerosols. Such comparison shows that particle phase concentrations of semi-volatile organic acids obtained from the filters collected by HVS are more than two times higher than concentrations obtained from filters collected using LVS denuder/filter system. In most cases, higher concentrations of organosulfates are observed in particles

  6. Real-Time Characterization of Particle and Gas Phase Diesel Emissions - Understanding the Influence of a Diesel Particulate Filter

    NASA Astrophysics Data System (ADS)

    Cross, E. S.; Sappok, A.; Carrasquillo, A. J.; Onasch, T. B.; Fortner, E.; Jayne, J.; Wong, V.; Worsnop, D. R.; Kroll, J. H.

    2010-12-01

    Diesel engine emissions constitute an important source of particulate black carbon (BC) and gas phase organics in the atmosphere. Particles composed of black carbon absorb incoming solar radiation having a net positive radiative forcing effect on the climate. Black carbon also has major air quality implications as BC particles from combustion sources are often coated with poly-aromatic hydrocarbons (PAHs), and are generally emitted in higher concentrations close to population centers. Regulations of diesel emissions target the mass of particulate matter (PM) and concentration of volatile gas phase organic compounds (VOC) produced. A third, potentially important component of diesel exhaust, is low volatility organic compounds (LVOC). Both the VOCs and LVOCs can lead to the formation of ultrafine particles (via homogeneous nucleation) and secondary organic aerosols (via oxidation). Recent development of mass spectrometric techniques to measure particulate black carbon and gas phase organics provide the opportunity to quantify and chemically characterize diesel emissions in real-time. Measurements of both the particulate and gas phase emissions from a medium-duty diesel engine will be presented. The experimental apparatus includes a diesel particulate filter (DPF) integrated in the exhaust line, which is a requirement for all 2007 and newer on-road diesel engines in the U.S. Measurements taken over the regeneration cycle of the DPF provide insight into how this after-treatment technology influences the gas phase and particle phase composition of the emissions. Gas phase measurements were made with a newly developed Total Gas-Phase Organic (TGO) instrument. Particulate species were characterized with a Soot Particle Aerosol Mass Spectrometer (SP-AMS). The combined utility of the TGO and SP-AMS instruments for emissions characterization studies will be demonstrated.

  7. Fuel Property, Emission Test, and Operability Results from a Fleet of Class 6 Vehicles Operating on Gas-to-Liquid Fuel and Catalyzed Diesel Particle Filters

    SciTech Connect

    Alleman, T. L.; Eudy, L.; Miyasato, M.; Oshinuga, A.; Allison, S.; Corcoran, T.; Chatterjee, S.; Jacobs, T.; Cherrillo, R. A.; Clark, R.; Virrels, I.; Nine, R.; Wayne, S.; Lansing, R.

    2005-11-01

    A fleet of six 2001 International Class 6 trucks operating in southern California was selected for an operability and emissions study using gas-to-liquid (GTL) fuel and catalyzed diesel particle filters (CDPF). Three vehicles were fueled with CARB specification diesel fuel and no emission control devices (current technology), and three vehicles were fueled with GTL fuel and retrofit with Johnson Matthey's CCRT diesel particulate filter. No engine modifications were made.

  8. Single Particle ICP-MS: Advances toward routine analysis of nanomaterials.

    PubMed

    Montaño, Manuel D; Olesik, John W; Barber, Angela G; Challis, Katie; Ranville, James F

    2016-07-01

    From its early beginnings in characterizing aerosol particles to its recent applications for investigating natural waters and waste streams, single particle inductively coupled plasma-mass spectrometry (spICP-MS) has proven to be a powerful technique for the detection and characterization of aqueous dispersions of metal-containing nanomaterials. Combining the high-throughput of an ensemble technique with the specificity of a single particle counting technique and the elemental specificity of ICP-MS, spICP-MS is capable of rapidly providing researchers with information pertaining to size, size distribution, particle number concentration, and major elemental composition with minimal sample perturbation. Recently, advances in data acquisition, signal processing, and the implementation of alternative mass analyzers (e.g., time-of-flight) has resulted in a wider breadth of particle analyses and made significant progress toward overcoming many of the challenges in the quantitative analysis of nanoparticles. This review provides an overview of spICP-MS development from a niche technique to application for routine analysis, a discussion of the key issues for quantitative analysis, and examples of its further advancement for analysis of increasingly complex environmental and biological samples. Graphical Abstract Single particle ICP-MS workflow for the analysis of suspended nanoparticles.

  9. A polypropylene cartridge filter with hematite nanoparticles for solid particles retention and arsenic removal

    NASA Astrophysics Data System (ADS)

    Tomaszewska, Justyna; Jakubiak, Szymon; Michalski, Jakub; Pronk, Wouter; Hug, Stephan J.; Kurzydłowski, Krzysztof J.

    2016-03-01

    In this article, we report a processing route for deposition of hematite (α-Fe2O3) nanoparticles into a cartridge filter composed of polypropylene (PP) non-woven fabric by a dip-coating method. During the process, a plasma activated non-woven fabric was immersed in an electrostatically stabilized aqueous hematite suspension under low vacuum conditions. Oxygen groups introduced onto the surface of the polymer provide a strong attachment of hematite nanoparticles to the polypropylene surface, confirmed under conditions of ultrasound. Preliminary tests demonstrated the efficiency of the cartridge in treating spring water with moderate arsenic concentrations, with kinetics and extent of adsorption showing a good correlation to a Langmuir adsorption model.

  10. Probabilistic tractography using Q-ball imaging and particle filtering: application to adult and in-utero fetal brain studies.

    PubMed

    Pontabry, J; Rousseau, F; Oubel, E; Studholme, C; Koob, M; Dietemann, J-L

    2013-04-01

    By assuming that orientation information of brain white matter fibers can be inferred from Diffusion-Weighted Magnetic Resonance Imaging (DW-MRI) measurements, tractography algorithms provide an estimation of the brain connectivity in vivo. The two key ingredients of tractography are the diffusion model (tensor, high-order tensor, Q-ball, etc.) and the means to deal with uncertainty during the tracking process (deterministic vs probabilistic mathematical framework). In this paper, we investigate the use of an analytical Q-ball model for the diffusion data within a well-formalized particle filtering framework. The proposed method is validated and compared to other tracking algorithms on the MICCAI'09 contest Fiber Cup phantom. Tractographies of in vivo adult and fetal brain Diffusion-Weighted Images (DWIs) are also shown to illustrate the robustness of the algorithm.

  11. A Rao-Blackwellized particle filter for joint parameter estimation and biomass tracking in a stochastic predator-prey system.

    PubMed

    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.

  12. Particle filter using a new resampling approach applied to LEO satellite autonomous orbit determination with a magnetometer

    NASA Astrophysics Data System (ADS)

    Wu, Jinjie; Liu, Kun; Wei, Jingbo; Han, Dapeng; Xiang, Junhua

    2012-12-01

    Particle filter (PF) is widely used in nonlinear and non-Gaussian systems. Resampling is one of the significant steps in PF. However, PF using conventional resampling approaches may lead to divergent solutions because of the degeneracy phenomenon or sample impoverishment associated with a multidimensional system. In this article, an efficient alternative to conventional resampling approaches, called adaptive partial systematic resampling (APSR) with Markov chain Monte Carlo move and intelligent roughening is proposed for satellite orbit determination using a magnetometer. The results of the new resampling approach are compared with conventional resampling approaches and with unscented Kalman filter (UKF) for various initial errors in position and velocity, measurement sampling periods, and measurement noises to evaluate and verify the performance of the new resampling approach. The results of the new resampling approach in all cases are significantly better than the results of conventional resampling approaches. The velocity accuracy of the orbit determination of APSR is slightly poorer than UKF for relatively small initial errors, and small Gaussian measurement noise. However, the proposed approach yields more robust and stable convergence than UKF under large initial errors, long measurement sampling period, large Gaussian measurement noise, or non-Gaussian noise.

  13. Inward particle transport at high collisionality in the Experimental Advanced Superconducting Tokamak

    SciTech Connect

    Wang, G. Q.; Ma, J.; Weiland, J.; Zang, Q.

    2013-10-15

    We have made the first drift wave study of particle transport in the Experimental Advanced Superconducting Tokamak (Wan et al., Nucl. Fusion 49, 104011 (2009)). The results reveal that collisions make the particle flux more inward in the high collisionality regime. This can be traced back to effects that are quadratic in the collision frequency. The particle pinch is due to electron trapping which is not very efficient in the high collisionality regime so the approach to equilibrium is slow. We have included also the electron temperature gradient (ETG) mode to give the right electron temperature gradient, since the Trapped Electron Mode (TE mode) is weak in this regime. However, at the ETG mode number ions are Boltzmann distributed so the ETG mode does not give particle transport.

  14. Simultaneous multi-vehicle detection and tracking framework with pavement constraints based on machine learning and particle filter algorithm

    NASA Astrophysics Data System (ADS)

    Wang, Ke; Huang, Zhi; Zhong, Zhihua

    2014-11-01

    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.

  15. Large-scale generic test stand for testing of multiple configurations of air filters utilizing a range of particle size distributions.

    PubMed

    Giffin, Paxton K; Parsons, Michael S; Unz, Ronald J; Waggoner, Charles A

    2012-05-01

    The Institute for Clean Energy Technology (ICET) at Mississippi State University has developed a test stand capable of lifecycle testing of high efficiency particulate air filters and other filters specified in American Society of Mechanical Engineers Code on Nuclear Air and Gas Treatment (AG-1) filters. The test stand is currently equipped to test AG-1 Section FK radial flow filters, and expansion is currently underway to increase testing capabilities for other types of AG-1 filters. The test stand is capable of producing differential pressures of 12.45 kPa (50 in. w.c.) at volumetric air flow rates up to 113.3 m(3)/min (4000 CFM). Testing is performed at elevated and ambient conditions for temperature and relative humidity. Current testing utilizes three challenge aerosols: carbon black, alumina, and Arizona road dust (A1-Ultrafine). Each aerosol has a different mass median diameter to test loading over a wide range of particles sizes. The test stand is designed to monitor and maintain relative humidity and temperature to required specifications. Instrumentation is implemented on the upstream and downstream sections of the test stand as well as on the filter housing itself. Representative data are presented herein illustrating the test stand's capabilities. Digital images of the filter pack collected during and after testing is displayed after the representative data are discussed. In conclusion, the ICET test stand with AG-1 filter testing capabilities has been developed and hurdles such as test parameter stability and design flexibility overcome.

  16. Delta-doped hybrid advanced detector for low energy particle detection

    NASA Technical Reports Server (NTRS)

    Cunningham, Thomas J. (Inventor); Fossum, Eric R. (Inventor); Nikzad, Shouleh (Inventor); Pain, Bedabrata (Inventor); Soli, George A. (Inventor)

    2000-01-01

    A delta-doped hybrid advanced detector (HAD) is provided which combines at least four types of technologies to create a detector for energetic particles ranging in energy from hundreds of electron volts (eV) to beyond several million eV. The detector is sensitive to photons from visible light to X-rays. The detector is highly energy-sensitive from approximately 10 keV down to hundreds of eV. The detector operates with milliwatt power dissipation, and allows non-sequential readout of the array, enabling various advanced readout schemes.

  17. Delta-doped hybrid advanced detector for low energy particle detection

    NASA Technical Reports Server (NTRS)

    Cunningham, Thomas J. (Inventor); Fossum, Eric R. (Inventor); Nikzad, Shouleh (Inventor); Pain, Bedabrata (Inventor); Soli, George A. (Inventor)

    2002-01-01

    A delta-doped hybrid advanced detector (HAD) is provided which combines at least four types of technologies to create a detector for energetic particles ranging in energy from hundreds of electron volts (eV) to beyond several million eV. The detector is sensitive to photons from visible light to X-rays. The detector is highly energy-sensitive from approximately 10 keV down to hundreds of eV. The detector operates with milliwatt power dissipation, and allows non-sequential readout of the array, enabling various advanced readout schemes.

  18. A Reliability-Based Particle Filter for Humanoid Robot Self-Localization in RoboCup Standard Platform League

    PubMed Central

    Sánchez, Eduardo Munera; Alcobendas, Manuel Muñoz; Noguera, Juan Fco. Blanes; Gilabert, Ginés Benet; Simó Ten, José E.

    2013-01-01

    This paper deals with the problem of humanoid robot localization and proposes a new method for position estimation that has been developed for the RoboCup Standard Platform League environment. Firstly, a complete vision system has been implemented in the Nao robot platform that enables the detection of relevant field markers. The detection of field markers provides some estimation of distances for the current robot position. To reduce errors in these distance measurements, extrinsic and intrinsic camera calibration procedures have been developed and described. To validate the localization algorithm, experiments covering many of the typical situations that arise during RoboCup games have been developed: ranging from degradation in position estimation to total loss of position (due to falls, ‘kidnapped robot’, or penalization). The self-localization method developed is based on the classical particle filter algorithm. The main contribution of this work is a new particle selection strategy. Our approach reduces the CPU computing time required for each iteration and so eases the limited resource availability problem that is common in robot platforms such as Nao. The experimental results show the quality of the new algorithm in terms of localization and CPU time consumption. PMID:24193098

  19. Research on sludge-fly ash ceramic particles (SFCP) for synthetic and municipal wastewater treatment in biological aerated filter (BAF).

    PubMed

    Zhao, Yaqin; Yue, Qinyan; Li, Renbo; Yue, Min; Han, Shuxin; Gao, Baoyu; Li, Qian; Yu, Hui

    2009-11-01

    Sludge-fly ash ceramic particles (SFCP) and clay ceramic particles (CCP) were employed in two lab-scale up-flow biological aerated filters (BAF) for wastewater treatment to investigate the availability of SFCP used as biofilm support compared with CCP. For synthetic wastewater, under the selected hydraulic retention times (HRT) of 1.5, 0.75 and 0.37 h, respectively, the removal efficiencies of chemical oxygen demand (COD(Cr)) and ammonium nitrogen (NH(4)(+)-N) in SFCP reactor were all higher than those of CCP reactor all through the media height. Moreover, better capabilities responding to loading shock and faster recovery after short intermittence were observed in the SFCP reactor compared with the CCP reactor. For municipal wastewater treatment, which was carried out under HRT of 0.75 h, air-liquid ratio of 7.5 and backwashing period of 48 h, the SFCP reactor also performed better than the CCP reactor, especially for the removal of NH(4)(+)-N.

  20. Performance of an N95 filtering facepiece particulate respirator and a surgical mask during human breathing: two pathways for particle penetration.

    PubMed

    Grinshpun, Sergey A; Haruta, Hiroki; Eninger, Robert M; Reponen, Tiina; McKay, Roy T; Lee, Shu-An

    2009-10-01

    The protection level offered by filtering facepiece particulate respirators and face masks is defined by the percentage of ambient particles penetrating inside the protection device. There are two penetration pathways: (1) through the faceseal leakage, and the (2) filter medium. This study aimed at differentiating the contributions of these two pathways for particles in the size range of 0.03-1 microm under actual breathing conditions. One N95 filtering facepiece respirator and one surgical mask commonly used in health care environments were tested on 25 subjects (matching the latest National Institute for Occupational Safety and Health fit testing panel) as the subjects performed conventional fit test exercises. The respirator and the mask were also tested with breathing manikins that precisely mimicked the prerecorded breathing patterns of the tested subjects. The penetration data obtained in the human subject- and manikin-based tests were compared for different particle sizes and breathing patterns. Overall, 5250 particle size- and exercise-specific penetration values were determined. For each value, the faceseal leakage-to-filter ratio was calculated to quantify the relative contributions of the two penetration pathways. The number of particles penetrating through the faceseal leakage of the tested respirator/mask far exceeded the number of those penetrating through the filter medium. For the N95 respirator, the excess was (on average) by an order of magnitude and significantly increased with an increase in particle size (p < 0.001): approximately 7-fold greater for 0.04 microm, approximately 10-fold for 0.1 microm, and approximately 20-fold for 1 microm. For the surgical mask, the faceseal leakage-to-filter ratio ranged from 4.8 to 5.8 and was not significantly affected by the particle size for the tested submicrometer fraction. Facial/body movement had a pronounced effect on the relative contribution of the two penetration pathways. Breathing intensity and

  1. Effects of an iron-based fuel-borne catalyst and a diesel particle filter on exhaust toxicity in lung cells in vitro.

    PubMed

    Steiner, Sandro; Czerwinski, Jan; Comte, Pierre; Heeb, Norbert V; Mayer, Andreas; Petri-Fink, Alke; Rothen-Rutishauser, Barbara

    2015-08-01

    Metal-containing fuel additives catalyzing soot combustion in diesel particle filters are used in a widespread manner, and with the growing popularity of diesel vehicles, their application is expected to increase in the near future. Detailed investigation into how such additives affect exhaust toxicity is therefore necessary and has to be performed before epidemiological evidence points towards adverse effects of their application. The present study investigates how the addition of an iron-based fuel additive (Satacen®3, 40 ppm Fe) to low-sulfur diesel affects the in vitro cytotoxic, oxidative, (pro-)inflammatory, and mutagenic activity of the exhaust of a passenger car operated under constant, low-load conditions by exposing a three-dimensional model of the human airway epithelium to complete exhaust at the air-liquid interface. We could show that the use of the iron catalyst without and with filter technology has positive as well as negative effects on exhaust toxicity compared to exhaust with no additives: it decreases the oxidative and, compared to a non-catalyzed diesel particle filter, the mutagenic potential of diesel exhaust, but increases (pro-)inflammatory effects. The presence of a diesel particle filter also influences the impact of Satacen®3 on exhaust toxicity, and the proper choice of the filter type to be used is of importance with regards to exhaust toxicity. Figure ᅟ.

  2. First results from solid state neutral particle analyzer on experimental advanced superconducting tokamak

    NASA Astrophysics Data System (ADS)

    Zhang, J. Z.; Zhu, Y. B.; Zhao, J. L.; Wan, B. N.; Li, J. G.; Heidbrink, W. W.

    2016-11-01

    Full function integrated, compact solid state neutral particle analyzers (ssNPA) based on absolute extreme ultraviolet silicon photodiode have been successfully implemented on the experimental advanced superconducting tokamak to measure energetic particle. The ssNPA system has been operated in advanced current mode with fast temporal and spatial resolution capabilities, with both active and passive charge exchange measurements. It is found that the ssNPA flux signals are increased substantially with neutral beam injection (NBI). The horizontal active array responds to modulated NBI beam promptly, while weaker change is presented on passive array. Compared to near-perpendicular beam, near-tangential beam brings more passive ssNPA flux and a broader profile, while no clear difference is observed on active ssNPA flux and its profile. Significantly enhanced intensities on some ssNPA channels have been observed during ion cyclotron resonant heating.

  3. First results from solid state neutral particle analyzer on experimental advanced superconducting tokamak.

    PubMed

    Zhang, J Z; Zhu, Y B; Zhao, J L; Wan, B N; Li, J G; Heidbrink, W W

    2016-11-01

    Full function integrated, compact solid state neutral particle analyzers (ssNPA) based on absolute extreme ultraviolet silicon photodiode have been successfully implemented on the experimental advanced superconducting tokamak to measure energetic particle. The ssNPA system has been operated in advanced current mode with fast temporal and spatial resolution capabilities, with both active and passive charge exchange measurements. It is found that the ssNPA flux signals are increased substantially with neutral beam injection (NBI). The horizontal active array responds to modulated NBI beam promptly, while weaker change is presented on passive array. Compared to near-perpendicular beam, near-tangential beam brings more passive ssNPA flux and a broader profile, while no clear difference is observed on active ssNPA flux and its profile. Significantly enhanced intensities on some ssNPA channels have been observed during ion cyclotron resonant heating.

  4. Recovering Bioactive Compounds from Olive Oil Filter Cake by Advanced Extraction Techniques

    PubMed Central

    Lozano-Sánchez, Jesús; Castro-Puyana, María; Mendiola, Jose A.; Segura-Carretero, Antonio; Cifuentes, Alejandro; Ibáñez, Elena

    2014-01-01

    The potential of by-products generated during extra-virgin olive oil (EVOO) filtration as a natural source of phenolic compounds (with demonstrated bioactivity) has been evaluated using pressurized liquid extraction (PLE) and considering mixtures of two GRAS (generally recognized as safe) solvents (ethanol and water) at temperatures ranging from 40 to 175 °C. The extracts were characterized by high-performance liquid chromatography (HPLC) coupled to diode array detection (DAD) and electrospray time-of-flight mass spectrometry (HPLC-DAD-ESI-TOF/MS) to determine the phenolic-composition of the filter cake. The best isolation procedure to extract the phenolic fraction from the filter cake was accomplished using ethanol and water (50:50, v/v) at 120 °C. The main phenolic compounds identified in the samples were characterized as phenolic alcohols or derivatives (hydroxytyrosol and its oxidation product), secoiridoids (decarboxymethylated and hydroxylated forms of oleuropein and ligstroside aglycones), flavones (luteolin and apigenin) and elenolic acid derivatives. The PLE extraction process can be applied to produce enriched extracts with applications as bioactive food ingredients, as well as nutraceuticals. PMID:25226536

  5. High temperature corrosion of advanced ceramic materials for hot-gas filters and heat exchangers

    SciTech Connect

    Kupp, E.R.; Trubelja, M.F.; Spear, K.E.; Tressler, R.E.

    1995-08-01

    Experimental corrosion studies of hot gas filter materials and heat exchanger materials in oxidizing combustion environments have been initiated. Filter materials from 3M Co. and DuPont Lanxide Composites Inc. are being tested over a range of temperatures, times and gas flows. It has been demonstrated that morphological and phase changes due to corrosive effects occur after exposure of the 3M material to a combustion environment for as little as 25 hours at 800{degrees}C. The study of heat exchanger materials has focused on enhancing the corrosion resistance of DuPont Lanxide Dimox{trademark} composite tubes by adding chromium to its surfaces by (1) heat treatments in a Cr{sub 2}O{sub 3} powder bed, or (2) infiltrating surface porosity with molten chromium nitrate. Each process is followed by a surface homogenization at 1500{degrees}C. The powder bed method has been most successful, producing continuous Cr-rich layers with thicknesses ranging from 20 to 250 {mu}m. As-received and Cr-modified DuPont Lanxide Dimox{trademark} samples will be reacted with commonly encountered coal-ash slags to determine the Cr effects on corrosion resistance.

  6. Plasmonic Color-Graded Nanosystems with Achromatic Subwavelength Architectures for Light Filtering and Advanced SERS Detection.

    PubMed

    Proietti Zaccaria, Remo; Bisio, Francesco; Das, Gobind; Maidecchi, Giulia; Caminale, Michael; Vu, Chinh Duc; De Angelis, Francesco; Di Fabrizio, Enzo; Toma, Andrea; Canepa, Maurizio

    2016-03-01

    Plasmonic color-graded systems are devices featuring a spatially variable plasmonic response over their surface. They are widely used as nanoscale color filters; their typical size is small enough to allow integration with miniaturized electronic circuits, paving the way to realize novel nanophotonic devices. Currently, most plasmonic color-graded systems are intrinsically discrete because their chromatic response exploits the tailored plasmon resonance of microarchitectures characterized by different size or geometry for each target color. Here, we report the realization of multifunctional plasmon-graded devices where continuously graded chromatic response is achieved by smoothly tuning the composition of the resonator material while simultaneously maintaining an achromatic nanoscale geometry. The result is a new class of versatile materials: we show their application as plasmonic filters with a potential pixel size smaller than half of the exciting wavelength but also as multiplexed surface-enhanced Raman spectroscopy (SERS) substrates. Many more implementations, such as photovoltaic efficiency boosters or color routers, await and will benefit from the low fabrication cost and intrinsic plasmonic flexibility of the presented systems.

  7. High temperature corrosion of advanced ceramic materials for hot gas filters and heat exchangers. Final report

    SciTech Connect

    Kupp, E.R.; Trubelja, K.E.; Spear, K.E.; Tressler, R.E.

    1995-08-01

    Experimental corrosion studies of hot gas filter materials and heat exchanger materials in oxidizing combustion environments have been initiated. Filter materials from 3M Co. and DuPont Lanxide Composites Inc. are being tested over a range of temperatures, times and gas flows. It has been demonstrated that morphological and phase changes due to corrosive effects occur after exposure of these materials to a simulated coal combustion environment for relatively short periods of time (10-50 hours). Heat exchanger tubes from DuPont Lanxide Composite Inc. were cut and infiltrated with Cr by heating in a Cr{sub 2}O{sub 3} powder bed. This resulted in continuous Cr-rich layers with thicknesses ranging from 20 to 250 {mu}m. The Cr-free and the Cr-infiltrated specimens were reacted with the molten Illinois No. 6 slag for 2 and 20 h at 1260{degrees}C, and the reaction layers examined with SEM and EDX. In the Cr-free specimens, the segregation of Fe and the precipitation of Fe{sub 2}O{sub 3} were detected near the liquid/gas interface, but no evidence of corrosion was present. In the Cr-infiltrate specimens, corrosion was evident, since a rearrangement and segregation of the Cr-rich grains occurred toward the surface of the molten slag. In addition, evidence of the diffusion of major quantities of Fe was observed from the liquid slag into the Cr-rich layer formed by infiltration.

  8. Factors Associated with Advanced Inferior Vena Cava Filter Removals: A Single-Center Retrospective Study of 203 Patients Over 7 Years

    SciTech Connect

    Dowell, Joshua D. Wagner, Daniel Elliott, Eric; Yildiz, Vedat O. Pan, Xueliang

    2016-02-15

    PurposeTo identify factors associated with advanced inferior vena cava filter (IVCF) retrieval to raise awareness on technical considerations, retrieval efficiency, and patient safety.Materials and MethodsA single-center retrospective review was performed of 203 consecutive retrievable IVC filters placed between 2007 and 2014. Attempted retrievals were classified as advanced if the routine “snare and sheath” technique was initially unsuccessful after multiple attempts, or an alternate endovascular maneuver or access site was utilized. Patient and filter characteristics were recorded.Results203 attempted retrievals were reviewed (48.7 % male, 51.2 % female, mean age 52.7 years, mean dwell time 109 days). Advanced retrievals were observed in 20 patients (9.8 %) (15 females, 5 males). Fluoroscopy time (p ≤ 0.01, 34.3 ± 21.1 and 5.3 ± 4.5 min for advanced retrievals and routine retrievals respectively, same below), gender (p = 0.031), and retrieval tilt angle (p ≤ 0.01, 5.7 ± 5.10° vs. 11.9 ± 11.03°) were associated with advanced retrievals. Females were 3.16 times more likely to have an advanced retrieval performed than males with a significantly higher tilt angle in those with advanced retrieval. History of cancer (p = 0.502), dwell time (p = 0.916), retrieval caval diameter (p = 0.053), placement caval diameter (p = 0.365), filter type (p = 0.710), strut perforation (p = 0.506), placement tilt angle (p = 0.311), and age (p = 0.558) were not found significantly associated with advanced retrievals.ConclusionsWomen are at increased risk for advanced filter retrieval secondary to a significant change in filter tilt over time compared to men, independent of filter type or competing demographic or filter risks, likely placing them at increased risk for higher procedural fluoroscopy times.

  9. Advanced In-Situ Detection and Chemical Analysis of Interstellar Dust Particles

    NASA Astrophysics Data System (ADS)

    Sternovsky, Z.; Gemer, A.; Gruen, E.; Horanyi, M.; Kempf, S.; Maute, K.; Postberg, F.; Srama, R.; Williams, E.; O'brien, L.; Rocha, J. R. R.

    2015-12-01

    The Ulysses dust detector discovered that interstellar dust particles pass through the solar system. The Hyperdsut instrument is developed for the in-situ detection and analysis of these particles to determine the elemental, chemical and isotopic compositions. Hyperdust builds on the heritage of previous successful instruments, e.g. the Cosmic Dust Analyzer (CDA) on Cassini. Hyperdust combines a highly sensitive Dust Trajectory Sensor (DTS) and the high mass resolution Chemical Analyzer (CA). The DTS will detect dust particles as small as 0.3 μm in radius, and the velocity vector information is used to confirm the interstellar origin and/or reveal the dynamics from the interactions within the solar system. The effective target area of the CA is > 600 cm2 achieves mass resolution in excess of 200, which is considerably higher than that of CDA, and is acheved by advanced ion optics design. The Hyperdust instrument is in the final phases of development to TRL 6.

  10. A Study Into the Effects of Kalman Filtered Noise in Advanced Guidance Laws of Missile Navigation

    DTIC Science & Technology

    2014-03-01

    air-to-air missile APN augmented proportional navigation AWG air weapons guidance DG differential geometry DOF degrees of freedom F fighter...not a viable substitute. The Phoenix was a long range missile with an advanced radar guidance system based heavily on the Tomcat AWG -9 radar. Using

  11. De-noising and retrieving algorithm of Mie lidar data based on the particle filter and the Fernald method.

    PubMed

    Li, Chen; Pan, Zengxin; Mao, Feiyue; Gong, Wei; Chen, Shihua; Min, Qilong

    2015-10-05

    The signal-to-noise ratio (SNR) of an atmospheric lidar decreases rapidly as range increases, so that maintaining high accuracy when retrieving lidar data at the far end is difficult. To avoid this problem, many de-noising algorithms have been developed; in particular, an effective de-noising algorithm has been proposed to simultaneously retrieve lidar data and obtain a de-noised signal by combining the ensemble Kalman filter (EnKF) and the Fernald method. This algorithm enhances the retrieval accuracy and effective measure range of a lidar based on the Fernald method, but sometimes leads to a shift (bias) in the near range as a result of the over-smoothing caused by the EnKF. This study proposes a new scheme that avoids this phenomenon using a particle filter (PF) instead of the EnKF in the de-noising algorithm. Synthetic experiments show that the PF performs better than the EnKF and Fernald methods. The root mean square error of PF are 52.55% and 38.14% of that of the Fernald and EnKF methods, and PF increases the SNR by 44.36% and 11.57% of that of the Fernald and EnKF methods, respectively. For experiments with real signals, the relative bias of the EnKF is 5.72%, which is reduced to 2.15% by the PF in the near range. Furthermore, the suppression impact on the random noise in the far range is also made significant via the PF. An extensive application of the PF method can be useful in determining the local and global properties of aerosols.

  12. Chromatic energy filter and characterization of laser-accelerated proton beams for particle therapy

    NASA Astrophysics Data System (ADS)

    Hofmann, Ingo; Meyer-ter-Vehn, Jürgen; Yan, Xueqing; Al-Omari, Husam

    2012-07-01

    The application of laser accelerated protons or ions for particle therapy has to cope with relatively large energy and angular spreads as well as possibly significant random fluctuations. We suggest a method for combined focusing and energy selection, which is an effective alternative to the commonly considered dispersive energy selection by magnetic dipoles. Our method is based on the chromatic effect of a magnetic solenoid (or any other energy dependent focusing device) in combination with an aperture to select a certain energy width defined by the aperture radius. It is applied to an initial 6D phase space distribution of protons following the simulation output from a Radiation Pressure Acceleration model. Analytical formula for the selection aperture and chromatic emittance are confirmed by simulation results using the TRACEWIN code. The energy selection is supported by properly placed scattering targets to remove the imprint of the chromatic effect on the beam and to enable well-controlled and shot-to-shot reproducible energy and transverse density profiles.

  13. Recent advancements of wide-angle polarization analysis with 3He neutron spin filters

    NASA Astrophysics Data System (ADS)

    Chen, W. C.; Gentile, T. R.; Ye, Q.; Kirchhoff, A.; Watson, S. M.; Rodriguez-Rivera, J. A.; Qiu, Y.; Broholm, C.

    2016-09-01

    Wide-angle polarization analysis with polarized 3He based neutron spin filters (NSFs) has recently been employed on the Multi-Axis Crystal Spectrometer (MACS) at the National Institute of Standards and Technology Center for Neutron Research (NCNR). Over the past several years, the apparatus has undergone many upgrades to address the fundamental requirements for wide angle polarization analysis using spin exchange optical pumping based 3He NSFs. In this paper, we report substantial improvements in the on-beam-line performance of the apparatus and progress toward routine user capability. We discuss new standard samples used for 3He NSF characterization and the flipping ratio measurement on MACS. We further discuss the management of stray magnetic fields produced by operation of superconducting magnets on the MACS instrument, which can significantly reduce the 3He polarization relaxation time. Finally, we present the results of recent development of horseshoe-shaped wide angle cells.

  14. Low pressure fabric filters advanced dedusting technology for high resistivity fly ash

    SciTech Connect

    Johnson, H.F.; Weltz, E.; Horst, J.

    1998-07-01

    Power Generation organizations in Europe are making increased use of lower cost (costs are typically 20--25% lower than the lowest cost European sourced coals) and lower sulfur content Australian and South African coals to improve competitiveness. The higher resistivity of the particulate from combustion of these coals due to their relatively low sulphur content and somewhat higher ash content makes the particulate more difficult to collect with an electrostatic precipitator (ESP) and favors the use of pulse jet fabric filters (PJFF) to meet stringent emission requirements. The Lentjes Bischoff low pressure PJFF design--based on Lurgi technology--has been purposely designed and developed since the late 1980's for very large scale applications and has been successfully applied to over 11,000 MW of coal fired boilers in a number of countries with the majority of installations in Australia and South Africa. Coal fired boiler sizes range from 30 to 670 MW and include conventional pulverized coal (p.c.) fired boilers as well as stoker fired, fluidized bed and the latest circulating fluidized bed fired boiler technologies. These applications are on new large base load installations as well as retrofitted into existing ESP casings. The design, construction and operating experience with two major installations covering both the retrofit of a PJFF into an existing ESP casing to meet new more stringent emission requirements and a new large base load installation are examined in detail. Firstly, the authors look at the retrofit of low pressure PJFF to the existing 6 x 280 MW boiler ESP casings at Gladstone Power Station, Queensland, Australia and then the new base load low pressure PJFF for the 6 x 670 MW boilers for Majuba Power Station, South Africa. The development of the modern low pressure pulse jet fabric filter has significantly improved the cost competitiveness of PJFF versus alternative technologies.

  15. High temperature corrosion of advanced ceramic materials for hot gas filters and heat exchangers

    SciTech Connect

    Crossland, C.E.; Shelleman, D.L.; Spear, K.E.

    1996-08-01

    A vertical flow-through furnace has been built to study the effect of corrosion on the morphology and mechanical properties of ceramic hot gas filters. Sections of 3M Type 203 and DuPont Lanxide SiC-SiC filter tubes were sealed at one end and suspended in the furnace while being subjected to a simulated coal combustion environment at 870{degrees}C. X-ray diffraction and electron microscopy is used to identify phase and morphology changes due to corrosion while burst testing determines the loss of mechanical strength after exposure to the combustion gases. Additionally, a thermodynamic database of gaseous silicon compounds is currently being established so that calculations can be made to predict important products of the reaction of the environment with the ceramics. These thermodynamic calculations provide useful information concerning the regimes where the ceramic may be degraded by material vaporization. To verify the durability and predict lifetime performance of ceramic heat exchangers in coal combustion environments, long-term exposure testing of stressed (internally pressurized) tubes must be performed in actual coal combustion environments. The authors have designed a system that will internally pressurize 2 inch OD by 48 inch long ceramic heat exchanger tubes to a maximum pressure of 200 psi while exposing the outer surface of the tubes to coal combustion gas at the Combustion and Environmental Research Facility (CERF) at the Pittsburgh Energy and Technology Center. Water-cooled, internal o-ring pressure seals were designed to accommodate the existing 6 inch by 6 inch access panels of the CERF. Tubes will be exposed for up to a maximum of 500 hours at temperatures of 2500 and 2600{degrees}F with an internal pressure of 200 psi. If the tubes survive, their retained strength will be measured using the high temperature tube burst test facility at Penn State University. Fractographic analysis will be performed to identify the failure source(s) for the tubes.

  16. A Novel Multi-Sensor Environmental Perception Method Using Low-Rank Representation and a Particle Filter for Vehicle Reversing Safety.

    PubMed

    Zhang, Zutao; Li, Yanjun; Wang, Fubing; Meng, Guanjun; Salman, Waleed; Saleem, Layth; Zhang, Xiaoliang; Wang, Chunbai; Hu, Guangdi; Liu, Yugang

    2016-06-09

    Environmental perception and information processing are two key steps of active safety for vehicle reversing. Single-sensor environmental perception cannot meet the need for vehicle reversing safety due to its low reliability. In this paper, we present a novel multi-sensor environmental perception method using low-rank representation and a particle filter for vehicle reversing safety. The proposed system consists of four main steps, namely multi-sensor environmental perception, information fusion, target recognition and tracking using low-rank representation and a particle filter, and vehicle reversing speed control modules. First of all, the multi-sensor environmental perception module, based on a binocular-camera system and ultrasonic range finders, obtains the distance data for obstacles behind the vehicle when the vehicle is reversing. Secondly, the information fusion algorithm using an adaptive Kalman filter is used to process the data obtained with the multi-sensor environmental perception module, which greatly improves the robustness of the sensors. Then the framework of a particle filter and low-rank representation is used to track the main obstacles. The low-rank representation is used to optimize an objective particle template that has the smallest L-1 norm. Finally, the electronic throttle opening and automatic braking is under control of the proposed vehicle reversing control strategy prior to any potential collisions, making the reversing control safer and more reliable. The final system simulation and practical testing results demonstrate the validity of the proposed multi-sensor environmental perception method using low-rank representation and a particle filter for vehicle reversing safety.

  17. A Novel Multi-Sensor Environmental Perception Method Using Low-Rank Representation and a Particle Filter for Vehicle Reversing Safety

    PubMed Central

    Zhang, Zutao; Li, Yanjun; Wang, Fubing; Meng, Guanjun; Salman, Waleed; Saleem, Layth; Zhang, Xiaoliang; Wang, Chunbai; Hu, Guangdi; Liu, Yugang

    2016-01-01

    Environmental perception and information processing are two key steps of active safety for vehicle reversing. Single-sensor environmental perception cannot meet the need for vehicle reversing safety due to its low reliability. In this paper, we present a novel multi-sensor environmental perception method using low-rank representation and a particle filter for vehicle reversing safety. The proposed system consists of four main steps, namely multi-sensor environmental perception, information fusion, target recognition and tracking using low-rank representation and a particle filter, and vehicle reversing speed control modules. First of all, the multi-sensor environmental perception module, based on a binocular-camera system and ultrasonic range finders, obtains the distance data for obstacles behind the vehicle when the vehicle is reversing. Secondly, the information fusion algorithm using an adaptive Kalman filter is used to process the data obtained with the multi-sensor environmental perception module, which greatly improves the robustness of the sensors. Then the framework of a particle filter and low-rank representation is used to track the main obstacles. The low-rank representation is used to optimize an objective particle template that has the smallest L-1 norm. Finally, the electronic throttle opening and automatic braking is under control of the proposed vehicle reversing control strategy prior to any potential collisions, making the reversing control safer and more reliable. The final system simulation and practical testing results demonstrate the validity of the proposed multi-sensor environmental perception method using low-rank representation and a particle filter for vehicle reversing safety. PMID:27294931

  18. Recent advances in polarized 3 He based neutron spin filter development

    NASA Astrophysics Data System (ADS)

    Chen, Wangchun; Gentile, Thomas; Erwin, Ross; Watson, Shannon; Krycka, Kathryn; Ye, Qiang; NCNR NIST Team; University of Maryland Team

    2015-04-01

    Polarized 3 He neutron spin filters (NSFs) are based on the strong spin-dependence of the neutron absorption cross section by 3 He. NSFs can polarize large area, widely divergent, and broadband neutron beams effectively and allow for combining a neutron polarizer and a spin flipper into a single polarizing device. The last capability utilizes 3 He spin inversion based on the adiabatic fast passage (AFP) nuclear magnetic resonance technique. Polarized 3 He NSFs are significantly expanding the polarized neutron measurement capabilities at the NIST Center for Neutron Research (NCNR). Here we present an overview of 3 He NSF applications to small-angle neutron scattering, thermal triple axis spectrometry, and wide-angle polarization analysis. We discuss a recent upgrade of our spin-exchange optical pumping (SEOP) systems that utilize chirped volume holographic gratings for spectral narrowing. The new capability allows us to polarize rubidium/potassium hybrid SEOP cells over a liter in volume within a day, with 3 He polarizations up to 88%, Finally we discuss how we can achieve nearly lossless 3 He polarization inversion with AFP.

  19. Space debris tracking based on fuzzy running Gaussian average adaptive particle filter track-before-detect algorithm

    NASA Astrophysics Data System (ADS)

    Torteeka, Peerapong; Gao, Peng-Qi; Shen, Ming; Guo, Xiao-Zhang; Yang, Da-Tao; Yu, Huan-Huan; Zhou, Wei-Ping; Zhao, You

    2017-02-01

    Although tracking with a passive optical telescope is a powerful technique for space debris observation, it is limited by its sensitivity to dynamic background noise. Traditionally, in the field of astronomy, static background subtraction based on a median image technique has been used to extract moving space objects prior to the tracking operation, as this is computationally efficient. The main disadvantage of this technique is that it is not robust to variable illumination conditions. In this article, we propose an approach for tracking small and dim space debris in the context of a dynamic background via one of the optical telescopes that is part of the space surveillance network project, named the Asia-Pacific ground-based Optical Space Observation System or APOSOS. The approach combines a fuzzy running Gaussian average for robust moving-object extraction with dim-target tracking using a particle-filter-based track-before-detect method. The performance of the proposed algorithm is experimentally evaluated, and the results show that the scheme achieves a satisfactory level of accuracy for space debris tracking.

  20. Effects of diesel particle filter retrofits and accelerated fleet turnover on drayage truck emissions at the Port of Oakland.

    PubMed

    Dallmann, Timothy R; Harley, Robert A; Kirchstetter, Thomas W

    2011-12-15

    Heavy-duty diesel drayage trucks have a disproportionate impact on the air quality of communities surrounding major freight-handling facilities. In an attempt to mitigate this impact, the state of California has mandated new emission control requirements for drayage trucks accessing ports and rail yards in the state beginning in 2010. This control rule prompted an accelerated diesel particle filter (DPF) retrofit and truck replacement program at the Port of Oakland. The impact of this program was evaluated by measuring emission factor distributions for diesel trucks operating at the Port of Oakland prior to and following the implementation of the emission control rule. Emission factors for black carbon (BC) and oxides of nitrogen (NO(x)) were quantified in terms of grams of pollutant emitted per kilogram of fuel burned using a carbon balance method. Concentrations of these species along with carbon dioxide were measured in the exhaust plumes of individual diesel trucks as they drove by en route to the Port. A comparison of emissions measured before and after the implementation of the truck retrofit/replacement rule shows a 54 ± 11% reduction in the fleet-average BC emission factor, accompanied by a shift to a more highly skewed emission factor distribution. Although only particulate matter mass reductions were required in the first year of the program, a significant reduction in the fleet-average NO(x) emission factor (41 ± 5%) was observed, most likely due to the replacement of older trucks with new ones.

  1. Application of a high-efficiency cabin air filter for simultaneous mitigation of ultrafine particle and carbon dioxide exposures inside passenger vehicles.

    PubMed

    Lee, Eon S; Zhu, Yifang

    2014-02-18

    Modern passenger vehicles are commonly equipped with cabin air filters but their filtration efficiency for ultrafine particle (UFP) is rather low. Although setting the vehicle ventilation system to recirculation (RC) mode can reduce in-cabin UFPs by ∼ 90%, passenger-exhaled carbon dioxide (CO2) can quickly accumulate inside the cabin. Using outdoor air (OA) mode instead can provide sufficient air exchange to prevent CO2 buildup, but in-cabin UFP concentrations would increase. To overcome this dilemma, we developed a simultaneous mitigation method for UFP and CO2 using high-efficiency cabin air (HECA) filtration in OA mode. Concentrations of UFP and other air pollutants were simultaneously monitored in and out of 12 different vehicles under 3 driving conditions: stationary, on local roadways, and on freeways. Under each experimental condition, data were collected with no filter, in-use original equipment manufacturer (OEM) filter, and two types of HECA filters. The HECA filters offered an average in-cabin UFP reduction of 93%, much higher than the OEM filters (∼ 50% on average). Throughout the measurements, the in-cabin CO2 concentration remained in the range of 620-930 ppm, significantly lower than the typical level of 2500-4000 ppm observed in the RC mode.

  2. Advancements in the Interferometric Measurements of Real Time Finishing Birefringent Filter's Crystal Plates

    NASA Astrophysics Data System (ADS)

    Gan, Ma; Mgan, Ya; Kushtal Skomorovsky, Gi, Vi; Domyshev, Gn; Sadokhin, Vp

    2006-10-01

    The finishing of birefringent plates consists of two processes: polishing and evaluation of a surface, which have been performed separately till now. The purpose of this work is achieving of high accuracy of the evaluation and machining of the plane-parallel plates from birefringent crystals, in particular of crystal plates of birefringent filters during their finishing. The developed process combines evaluation and polishing in an interactive way. We have found modes of treatment, shape of polisher, have designed interferometer, with a mirror arranged in polisher. Visual checking of optical thickness comparatively with reference plate was carried out using the interference fringes of equal birefringence, and checking of an optical wedge - by interference rings of an equal inclination. The automated processing of TV camera interference fringes was impossible, because of gaps of interference fringes on polishing cells above the mirror. Therefore a special software was developed for processing of a complex fringe pattern interferogram. Software FastInterf uses furrier analysis technique which allows to process an interferogram with multiply gaps. Interferograms are registered by a high resolution TV camera (1280 ×1024). Automatic processing of a fringe interferogram using FastInterf software takes less then one second. The influence of gaps is excluded, and the flat field is taken into account. Software provides full 3D surface and wavefront maps. Aberration analysis of a wavefront gives information on thickness of a plate comparatively with a reference one, optical wedge of plate and azimuth of an inclination of wave front. Moreover, software provides a control of surface quality. The measuring device, features of the software are described and process of interferometric evaluation during polishing is illustrated.

  3. Particulate Emissions Control using Advanced Filter Systems: Final Report for Argonne National Laboratory, Corning Inc. and Hyundai Motor Company CRADA Project

    SciTech Connect

    Seong, Hee Je; Choi, Seungmok

    2015-10-09

    This is a 3-way CRADA project working together with Corning, Inc. and Hyundai Motor Co. (HMC). The project is to understand particulate emissions from gasoline direct-injection engines (GDI) and their physico-chemical properties. In addition, this project focuses on providing fundamental information about filtration and regeneration mechanisms occurring in gasoline particulate filter (GPF) systems. For the work, Corning provides most advanced filter substrates for GPF applications and HMC provides three-way catalyst (TWC) coating services of these filter by way of a catalyst coating company. Then, Argonne National Laboratory characterizes fundamental behaviors of filtration and regeneration processes as well as evaluated TWC functionality for the coated filters. To examine aging impacts on TWC and GPF performance, the research team evaluates gaseous and particulate emissions as well as back-pressure increase with ash loading by using an engine-oil injection system to accelerate ash loading in TWC-coated GPFs.

  4. How does breathing frequency affect the performance of an N95 filtering facepiece respirator and a surgical mask against surrogates of viral particles?

    PubMed

    He, Xinjian; Reponen, Tiina; McKay, Roy; Grinshpun, Sergey A

    2014-01-01

    Breathing frequency (breaths/min) differs among individuals and levels of physical activity. Particles enter respirators through two principle penetration pathways: faceseal leakage and filter penetration. However, it is unknown how breathing frequency affects the overall performance of N95 filtering facepiece respirators (FFRs) and surgical masks (SMs) against viral particles, as well as other health-relevant submicrometer particles. A FFR and SM were tested on a breathing manikin at four mean inspiratory flows (MIFs) (15, 30, 55, and 85 L/min) and five breathing frequencies (10, 15, 20, 25, and 30 breaths/min). Filter penetration (Pfilter) and total inward leakage (TIL) were determined for the tested respiratory protection devices against sodium chloride (NaCl) aerosol particles in the size range of 20 to 500 nm. "Faceseal leakage-to-filter" (FLTF) penetration ratios were calculated. Both MIF and breathing frequency showed significant effects (p < 0.05) on Pfilter and TIL. Increasing breathing frequency increased TIL for the N95 FFR whereas no clear trends were observed for the SM. Increasing MIF increased Pfilter and decreased TIL resulting in decreasing FLTF ratio. Most of FLTF ratios were >1, suggesting that the faceseal leakage was the primary particle penetration pathway at various breathing frequencies. Breathing frequency is another factor (besides MIF) that can significantly affect the performance of N95 FFRs, with higher breathing frequencies increasing TIL. No consistent trend of increase or decrease of TIL with either MIF or breathing frequency was observed for the tested SM. To potentially extend these findings beyond the manikin/breathing system used, future studies are needed to fully understand the mechanism causing the breathing frequency effect on the performance of respiratory protection devices on human subjects.

  5. Effects of continuously regenerating diesel particulate filters on regulated emissions and number-size distribution of particles emitted from a diesel engine.

    PubMed

    Liu, Zhihua; Shah, Asad Naeem; Ge, Yunshan; Ding, Yan; Tan, Jianwei; Jiang, Lei; Yu, Linxiao; Zhao, Wei; Wang, Chu; Zeng, Tao

    2011-01-01

    The effects of continuously regenerating diesel particulate filter (CRDPF) systems on regulated gaseous emissions, and number-size distribution and mass of particles emanated from a diesel engine have been investigated in this study. Two CRDPF units (CRDPF-1 and CRDPF-2) with different specifications were separately retrofitted to the engine running with European steady-state cycle (ESC). An electrical low pressure impactor (ELPI) was used for particle number-size distribution measurement and mass estimation. The conversion/reduction rate (R(CR)) of hydrocarbons (HC) and carbon monoxide (CO) across CRDPF-1 was 83% and 96.3%, respectively. Similarly, the R(CR) of HC and CO and across CRDPF-2 was 91.8% and 99.1%, respectively. The number concentration of particles and their concentration peaks; nuclei mode, accumulation mode and total particles; and particle mass were highly reduced with the CRDPF units. The nuclei mode particles at downstream of CRDPF-1 and CRDPF-2 decreased by 99.9% to 100% and 97.8% to 99.8% respectively; and the particle mass reduced by 73% to 92.2% and 35.3% to 72.4%, respectively, depending on the engine conditions. In addition, nuclei mode particles increased with the increasing of engine speed due to the heterogeneous nucleation initiated by the higher exhaust temperature, while accumulation mode particles were higher at higher loads due to the decrease in the air-to-fuel ratio (A/F) at higher loads.

  6. Plasma asymmetry due to the magnetic filter in fusion-type negative ion sources: Comparisons between two and three-dimensional particle-in-cell simulations

    SciTech Connect

    Fubiani, G. Boeuf, J. P.

    2014-07-15

    Previously reported 2D Particle-In-Cell Monte Carlo Collisions (PIC-MCC) simulations of negative ion sources under conditions similar to those of the ITER neutral beam injection system have shown that the presence of the magnetic filter tends to generate asymmetry in the plasma properties in the extraction region. In this paper, we show that these conclusions are confirmed by 3D PIC-MCC simulations and we provide quantitative comparisons between the 2D and 3D model predictions.

  7. Filter and method of fabricating

    DOEpatents

    Janney, Mark A.

    2006-02-14

    A method of making a filter includes the steps of: providing a substrate having a porous surface; applying to the porous surface a coating of dry powder comprising particles to form a filter preform; and heating the filter preform to bind the substrate and the particles together to form a filter.

  8. Analysis of the bromate-sulfite-ferrocyanide pH oscillator using the particle filter: toward the automated modeling of complex chemical systems.

    PubMed

    Sato, Naoya; Hasegawa, Hiroshi H; Kimura, Rika; Mori, Yoshihito; Okazaki, Noriaki

    2010-09-23

    This study was aimed at identifying a quantitatively accurate reaction model of the bromate-sulfilte-ferrocyanide (BSF) pH oscillator by using the simulation-based model estimation algorithm known as the particle filter. The Rbai-Kaminaga-Hanazaki (RKH) model proposed for the BSF system was extended by adding the protonation equilibrium of SO42-, for which the particle filter analysis was carried out to optimize the rate constants involved with reference to the measured pH oscillation data. The extended RKH model with the optimized rate constants almost completely reproduced the measured pH oscillations and the state diagram, showing the validity of the present analysis. Chemical oscillators such as the BSF system show drastic switching of the dominant reaction path, which strongly disturbs the convergence of the rate constants if the objective function is defined in a conventional manner to reflect only a single time step datum. In this study, the objective function was defined as the residual sum of squares with respect to pH taken over an interval longer than one oscillatory period, so that all of the relevant reaction steps can contribute to the objective function. This is the first report which exemplifies the effectiveness of the particle filter in the analysis of real complex chemical systems.

  9. Advancements in the Coupling of State-of-the-Art Energetic Particle and Magnetohydrodynamic Simulations

    NASA Astrophysics Data System (ADS)

    Gorby, M.

    2015-12-01

    Recent advancements in coupling the Earth Moon Mars Radiation Environment Module (EMMREM) and two MHD models, Magnetohydrodynamics Around a Sphere (MAS) and ENLIL, have yielded promising results for predicting differential energy flux and radiation doses at 1AU. The EMMREM+MAS coupling focuses on the details of particle acceleration due to CMEs initiated low in the corona (1Rs - 20Rs). The EMMREM+ENLIL coupling gives results for CMEs initiated at ~20Rs and is part of a predictive capability being developed in conjunction with the CCMC. The challenge in forming large solar energetic particle events in both the prompt scenario lower down or for a gradual CME further out is to have enhanced scattering within the acceleration regions while also allowing for efficient escape of accelerated particles downstream. We present here details of the MHD parameters and topology of a CME around the acceleration regions in the early evolution (below 2Rs), dose and flux predictions at 1AU, and how compression regions vs. shocks affect the evolution and spectrum of an SEP event.

  10. Advances in Quantifying the Radiative Effects of Aerosol Particles on Climate from Airborne Field Studies

    NASA Astrophysics Data System (ADS)

    Pilewskie, P.; Schmidt, K. S.; Coddington, O.; Bergstrom, R.; Redemann, J.

    2007-12-01

    In the fourth assessment report of the Intergovernmental Panel on Climate Change, large uncertainties persist in estimates of climate forcing by aerosol particles. One contributor to this uncertainty is the poorly quantified vertical distribution of solar radiation absorbed by aerosol particles, from the regional to global scale. Another is the spectral and spatial variability of surface albedo, an effect that can dominate the top-of-atmosphere perturbations due to aerosol scattering and absorption, particularly over land. Over the past three years a number of intensive airborne field experiments (ICARTT, MILAGRO, GoMACCS) have contributed significantly to our understanding of the impact of pollution outflow from urban-industrial centers on radiative forcing, using spectrally resolved radiometric measurements and novel observationally-based methods to derive forcing efficiency and flux divergence. We present an overview of some of the most significant advances in direct radiative forcing realized by these studies, and recommendations on where the greatest challenges remain. In addition we present findings from these experiments on the influence of aerosol particles on cloud radiative properties, a potentially greater effect but even more uncertain than direct radiative forcing.

  11. Advances in Single-Particle Electron Cryomicroscopy Structure Determination applied to Sub-tomogram Averaging

    PubMed Central

    Bharat, Tanmay A.M.; Russo, Christopher J.; Löwe, Jan; Passmore, Lori A.; Scheres, Sjors H.W.

    2015-01-01

    Summary Recent innovations in specimen preparation, data collection, and image processing have led to improved structure determination using single-particle electron cryomicroscopy (cryo-EM). Here we explore some of these advances to improve structures determined using electron cryotomography (cryo-ET) and sub-tomogram averaging. We implement a new three-dimensional model for the contrast transfer function, and use this in a regularized likelihood optimization algorithm as implemented in the RELION program. Using direct electron detector data, we apply both single-particle analysis and sub-tomogram averaging to analyze radiation-induced movements of the specimen. As in single-particle cryo-EM, we find that significant sample movements occur during tomographic data acquisition, and that these movements are substantially reduced through the use of ultrastable gold substrates. We obtain a sub-nanometer resolution structure of the hepatitis B capsid, and show that reducing radiation-induced specimen movement may be central to attempts at further improving tomogram quality and resolution. PMID:26256537

  12. Verification of sub-grid filtered drag models for gas-particle fluidized beds with immersed cylinder arrays

    SciTech Connect

    Sarkar, Avik; Sun, Xin; Sundaresan, Sankaran

    2014-04-23

    The accuracy of coarse-grid multiphase CFD simulations of fluidized beds may be improved via the inclusion of filtered constitutive models. In our previous study (Sarkar et al., Chem. Eng. Sci., 104, 399-412), we developed such a set of filtered drag relationships for beds with immersed arrays of cooling tubes. Verification of these filtered drag models is addressed in this work. Predictions from coarse-grid simulations with the sub-grid filtered corrections are compared against accurate, highly-resolved simulations of full-scale turbulent and bubbling fluidized beds. The filtered drag models offer a computationally efficient yet accurate alternative for obtaining macroscopic predictions, but the spatial resolution of meso-scale clustering heterogeneities is sacrificed.

  13. The movement of particles in liquid metals under gravity forces and the interaction of particles with advancing solid-liquid interface

    NASA Technical Reports Server (NTRS)

    Weinberg, F.

    1984-01-01

    The problems of shrinkage and gas porosity are discussed. Gravity forces enhance the removal of gas bubbles from a metal melt and contribute to the feeding of shrinkage porosity in castings. Experiments are reviewed which determine how large a density difference is required for metal particles to float or sink in a metal melt and to what extent do factors not considered in Stokes Law influence particle movement in a real system. As to the interaction of particles with an advancing solid-liquid interface, the results indicate that the metal particles are not rejected in a metal melt, and that concentrations of particles in a metal following solidification are due to other factors.

  14. Solid colloidal optical wavelength filter

    DOEpatents

    Alvarez, Joseph L.

    1992-01-01

    A solid colloidal optical wavelength filter includes a suspension of spheal particles dispersed in a coagulable medium such as a setting plastic. The filter is formed by suspending spherical particles in a coagulable medium; agitating the particles and coagulable medium to produce an emulsion of particles suspended in the coagulable medium; and allowing the coagulable medium and suspended emulsion of particles to cool.

  15. Elastic vibrations of a fiber due to impact of an aerosol particle and their influence on the efficiency of fibrous filters

    NASA Astrophysics Data System (ADS)

    Chernyakov, A. L.; Kirsch, A. A.; Kirsch, V. A.

    2011-05-01

    The excitation of sound vibrations of a cylindrical fine fiber due to the impact of a spherical aerosol particle is investigated. The equations describing the dynamics of impact are derived for an arbitrary shooting parameter. The coefficient of restitution is calculated, and its analytical approximation is obtained. It is shown, for the case of long fibers, that the coefficient of restitution depends upon a single parameter λc. The parameter λc depends on the particle radial velocity component near the fiber surface, the mass of the particle, the density of the fiber, the modulus of elasticity, and the geometric parameters of the fiber and the particle. The inertial deposition of submicron aerosol particles on fine fibers in a filter is considered. The efficiency of filtration is studied as a function of the gas flow velocity. The existence of a critical flow velocity U*, below which the losses of particle energy during collision have no effect on the efficiency, is demonstrated. For velocities higher than the critical velocity, the filtration efficiency is dependent on the mechanisms of nonelastic losses of the particle's energy. Its value can be significantly lower than that estimated when particle rebound effects are neglected. After they have rebounded, some particles are not able to attain the initial high velocities in the stream, thus depositing on neighboring fibers. The dynamics of these particles is investigated. For this case, it is shown that the filtration efficiency is dependent on the velocity distribution of the rebounded particles and that it increases with the packing density of fibers. A qualitative difference between the asymptotic behavior of a fiber and that of a flat plate is found long after the initial impulse.

  16. Deposition rate and etching rate due to neutral radicals and dust particles measured using QCMs together with a dust eliminating filter

    NASA Astrophysics Data System (ADS)

    Katayama, Ryu; Koga, Kazunori; Yamashita, Daisuke; Kamataki, Kunihiro; Seo, Hyunwoong; Itagaki, Naho; Shiratani, Masaharu; Ashikawa, Naoko; Tokitani, Masayuki; Masuzaki, Suguru; Nishimura, Kiyohiko; Sagara, Akio; the LHD experimental Group Team

    2015-09-01

    We have developed an in-situ method for measuring deposition rate of radicals and dust particles using quartz crystal microbalances (QCMs) together with a dust eliminating filter. The QCMs have three channels of quartz crystals. Channel 1 was used to measure total deposition rate due to radicals and dust particles. Channel 2 was covered with a dust eliminating filter. Channel 3 was covered with a stainless-steel plate. Moreover, all QCMs are covered with a grounded stainless steel mesh for suppressing influx of charged particles. The measurements were conducted in the Large Helical Device in the National Institute for Fusion Science, Japan. Although the deposition measurements during the discharges were difficult, we obtained deposition rate and etching rate by comparing the data before and after each discharge. The frequency difference for channel 1 changes from 0.1 Hz (etching) to -0.5 Hz (deposition), while those for channels 2 and 3 are within a range of +/-0.1 Hz and +/-0.05 Hz, respectively. The QCM method gives information on deposition rate and etching rate due to neutral radicals and dust particles.

  17. Electrochemical Advanced Oxidation Process for Shipboard Final Purification of Filtered Black Water, Gray Water, and Bilge Water, Vol. 1

    DTIC Science & Technology

    2001-08-01

    Shipboard Final Purification of Filtered Black Water , Gray Water , and Bilge Water O. Weres, PhD and H.E. O’Donnell Sonoma Research Company Napa...Process for Shipboard Final Purification of Filtered Black Water , Gray Water , and Bilge Water 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...Shipboard Final Purification of Filtered Black Water , Gray Water , and Bilge Water Final Report Submitted to: SERDP Office 901 North Stuart Street, Suite

  18. Observation of Energetic Particle Driven Modes Relevant to Advanced Tokamak Regimes

    SciTech Connect

    R. Nazikian; B. Alper; H.L. Berk; D. Borba; C. Boswell; R.V. Budny; K.H. Burrell; C.Z. Cheng; E.J. Doyle; E. Edlund; R.J. Fonck; A. Fukuyama; N.N. Gorelenkov; C.M. Greenfield; D.J. Gupta; M. Ishikawa; R.J. Jayakumar; G.J. Kramer; Y. Kusama; R.J. La Haye; G.R. McKee; W.A. Peebles; S.D. Pinches; M. Porkolab; J. Rapp; T.L. Rhodes; S.E. Sharapov; K. Shinohara; J.A. Snipes; W.M. Solomon; E.J. Strait; M. Takechi; M.A. Van Zeeland; W.P. West; K.L. Wong; S. Wukitch; L. Zeng

    2004-10-21

    Measurements of high-frequency oscillations in JET [Joint European Torus], JT-60U, Alcator C-Mod, DIII-D, and TFTR [Tokamak Fusion Test Reactor] plasmas are contributing to a new understanding of fast ion-driven instabilities relevant to Advanced Tokamak (AT) regimes. A model based on the transition from a cylindrical-like frequency-chirping mode to the Toroidal Alfven Eigenmode (TAE) has successfully encompassed many of the characteristics seen in experiments. In a surprising development, the use of internal density fluctuation diagnostics has revealed many more modes than has been detected on edge magnetic probes. A corollary discovery is the observation of modes excited by fast particles traveling well below the Alfven velocity. These observations open up new opportunities for investigating a ''sea of Alfven Eigenmodes'' in present-scale experiments, and highlight the need for core fluctuation and fast ion measurements in a future burning-plasma experiment.

  19. Full Useful Life (120,000 miles) Exhaust Emission Performance of a NOx Adsorber and Diesel Particle Filter Equipped Passenger Car and Medium-duty Engine in Conjunction with Ultra Low Sulfur Fuel (Presentation)

    SciTech Connect

    Thornton, M.; Tatur, M.; Tomazic, D.; Weber, P.; Webb, C.

    2005-08-25

    Discusses the full useful life exhaust emission performance of a NOx (nitrogen oxides) adsorber and diesel particle filter equipped light-duty and medium-duty engine using ultra low sulfur diesel fuel.

  20. A novel method for online analysis of gas and particle composition: description and evaluation of a Filter Inlet for Gases and AEROsols (FIGAERO)

    NASA Astrophysics Data System (ADS)

    Lopez-Hilfiker, F. D.; Mohr, C.; Ehn, M.; Rubach, F.; Kleist, E.; Wildt, J.; Mentel, Th. F.; Lutz, A.; Hallquist, M.; Worsnop, D.; Thornton, J. A.

    2014-04-01

    We describe a novel inlet that allows measurement of both gas and particle molecular composition when coupled to mass spectrometric, chromatographic, or optical sensors: the Filter Inlet for Gases and AEROsols (FIGAERO). The design goals for the FIGAERO are to allow unperturbed observation of ambient air while simultaneously analyzing gases and collecting particulate matter on a Teflon® (hereafter Teflon) filter via an entirely separate sampling port. The filter is analyzed periodically by the same sensor on hourly or faster timescales using temperature-programmed thermal desorption. We assess the performance of the FIGAERO by coupling it to a high-resolution time-of-flight chemical-ionization mass spectrometer (HRToF-CIMS) in laboratory chamber studies of α-pinene oxidation and field measurements at a boreal forest location. Low instrument backgrounds give detection limits of ppt or lower for compounds in the gas-phase and in the picogram m-3 range for particle phase compounds. The FIGAERO-HRToF-CIMS provides molecular information about both gases and particle composition on the 1 Hz and hourly timescales, respectively for hundreds of compounds. The FIGAERO thermal desorptions are highly reproducible (better than 10%), allowing a calibrated assessment of the effective volatility of desorbing compounds and the role of thermal decomposition during the desorption process. We show that the often multi-modal desorption thermograms arising from secondary organic aerosol (SOA) provide additional insights into molecular composition and/or particle morphology, and exhibit changes with changes in SOA formation or aging pathways.

  1. State estimation in large-scale open channel networks using sequential Monte Carlo methods: Optimal sampling importance resampling and implicit particle filters

    NASA Astrophysics Data System (ADS)

    Rafiee, Mohammad; Barrau, Axel; Bayen, Alexandre M.

    2013-06-01

    This article investigates the performance of Monte Carlo-based estimation methods for estimation of flow state in large-scale open channel networks. After constructing a state space model of the flow based on the Saint-Venant equations, we implement the optimal sampling importance resampling filter to perform state estimation in a case in which measurements are available at every time step. Considering a case in which measurements become available intermittently, a random-map implementation of the implicit particle filter is applied to estimate the state trajectory in the interval between the measurements. Finally, some heuristics are proposed, which are shown to improve the estimation results and lower the computational cost. In the first heuristics, considering the case in which measurements are available at every time step, we apply the implicit particle filter over time intervals of a desired size while incorporating all the available measurements over the corresponding time interval. As a second heuristic method, we introduce a maximum a posteriori (MAP) method, which does not require sampling. It will be seen, through implementation, that the MAP method provides more accurate results in the case of our application while having a smaller computational cost. All estimation methods are tested on a network of 19 tidally forced subchannels and 1 reservoir, Clifton Court Forebay, in Sacramento-San Joaquin Delta in California, and numerical results are presented.

  2. Lithium-ion battery state of health monitoring and remaining useful life prediction based on support vector regression-particle filter

    NASA Astrophysics Data System (ADS)

    Dong, Hancheng; Jin, Xiaoning; Lou, Yangbing; Wang, Changhong

    2014-12-01

    Lithium-ion batteries are used as the main power source in many electronic and electrical devices. In particular, with the growth in battery-powered electric vehicle development, the lithium-ion battery plays a critical role in the reliability of vehicle systems. In order to provide timely maintenance and replacement of battery systems, it is necessary to develop a reliable and accurate battery health diagnostic that takes a prognostic approach. Therefore, this paper focuses on two main methods to determine a battery's health: (1) Battery State-of-Health (SOH) monitoring and (2) Remaining Useful Life (RUL) prediction. Both of these are calculated by using a filter algorithm known as the Support Vector Regression-Particle Filter (SVR-PF). Models for battery SOH monitoring based on SVR-PF are developed with novel capacity degradation parameters introduced to determine battery health in real time. Moreover, the RUL prediction model is proposed, which is able to provide the RUL value and update the RUL probability distribution to the End-of-Life cycle. Results for both methods are presented, showing that the proposed SOH monitoring and RUL prediction methods have good performance and that the SVR-PF has better monitoring and prediction capability than the standard particle filter (PF).

  3. Reduction in (pro-)inflammatory responses of lung cells exposed in vitro to diesel exhaust treated with a non-catalyzed diesel particle filter

    NASA Astrophysics Data System (ADS)

    Steiner, Sandro; Czerwinski, Jan; Comte, Pierre; Müller, Loretta L.; Heeb, Norbert V.; Mayer, Andreas; Petri-Fink, Alke; Rothen-Rutishauser, Barbara

    2013-12-01

    Increasingly stringent regulation of particulate matter emissions from diesel vehicles has led to the widespread use of diesel particle filters (DPFs), the effect of which on exhaust toxicity is so far poorly understood. We exposed a cellular model of the human respiratory epithelium at the air-liquid interface to non-catalyzed wall-flow DPF-filtered diesel exhaust and compared the resulting biological responses to the ones observed upon exposure to unfiltered exhaust. Filtered diesel exhaust acted highly oxidative, even though to a lesser extent than unfiltered exhaust (quantification of total reduced glutathione), and both exhaust types triggered comparable responses to oxidative stress (measurement of heme-oxygenase 1 (HMOX1) and superoxide-dismutase (SOD1) gene expression). Further, diesel exhaust filtration significantly reduced pro-inflammatory responses (measurement of tumor necrosis factor (TNF) and interleukin-8 (IL-8) gene expression and quantification of the secretion of their gene products TNF-α and IL-8). Because inflammatory processes are central to the onset of adverse respiratory health effects caused by diesel exhaust inhalation, our results imply that DPFs may make a valuable contribution to the detoxification of diesel vehicle emissions. The induction of significant oxidative stress by filtered diesel exhaust however, also implies that the non-particulate exhaust components also need to be considered for lung cell risk assessment.

  4. The Advanced Composition Explorer Shock Database and Application to Particle Acceleration Theory

    NASA Technical Reports Server (NTRS)

    Parker, L. Neergaard; Zank, G. P.

    2015-01-01

    The theory of particle acceleration via diffusive shock acceleration (DSA) has been studied in depth by Gosling et al. (1981), van Nes et al. (1984), Mason (2000), Desai et al. (2003), Zank et al. (2006), among many others. Recently, Parker and Zank (2012, 2014) and Parker et al. (2014) using the Advanced Composition Explorer (ACE) shock database at 1 AU explored two questions: does the upstream distribution alone have enough particles to account for the accelerated downstream distribution and can the slope of the downstream accelerated spectrum be explained using DSA? As was shown in this research, diffusive shock acceleration can account for a large population of the shocks. However, Parker and Zank (2012, 2014) and Parker et al. (2014) used a subset of the larger ACE database. Recently, work has successfully been completed that allows for the entire ACE database to be considered in a larger statistical analysis. We explain DSA as it applies to single and multiple shocks and the shock criteria used in this statistical analysis. We calculate the expected injection energy via diffusive shock acceleration given upstream parameters defined from the ACE Solar Wind Electron, Proton, and Alpha Monitor (SWEPAM) data to construct the theoretical upstream distribution. We show the comparison of shock strength derived from diffusive shock acceleration theory to observations in the 50 keV to 5 MeV range from an instrument on ACE. Parameters such as shock velocity, shock obliquity, particle number, and time between shocks are considered. This study is further divided into single and multiple shock categories, with an additional emphasis on forward-forward multiple shock pairs. Finally with regard to forward-forward shock pairs, results comparing injection energies of the first shock, second shock, and second shock with previous energetic population will be given.

  5. Advances in 4D Treatment Planning for Scanned Particle Beam Therapy — Report of Dedicated Workshops

    PubMed Central

    Bert, Christoph; Graeff, Christian; Riboldi, Marco; Nill, Simeon; Baroni, Guido; Knopf, Antje-Christin

    2014-01-01

    We report on recent progress in the field of mobile tumor treatment with scanned particle beams, as discussed in the latest editions of the 4D treatment planning workshop. The workshop series started in 2009, with about 20 people from 4 research institutes involved, all actively working on particle therapy delivery and development. The first workshop resulted in a summary of recommendations for the treatment of mobile targets, along with a list of requirements to apply these guidelines clinically. The increased interest in the treatment of mobile tumors led to a continuously growing number of attendees: the 2012 edition counted more than 60 participants from 20 institutions and commercial vendors. The focus of research discussions among workshop participants progressively moved from 4D treatment planning to complete 4D treatments, aiming at effective and safe treatment delivery. Current research perspectives on 4D treatments include all critical aspects of time resolved delivery, such as in-room imaging, motion detection, beam application, and quality assurance techniques. This was motivated by the start of first clinical treatments of hepato cellular tumors with a scanned particle beam, relying on gating or abdominal compression for motion mitigation. Up to date research activities emphasize significant efforts in investigating advanced motion mitigation techniques, with a specific interest in the development of dedicated tools for experimental validation. Potential improvements will be made possible in the near future through 4D optimized treatment plans that require upgrades of the currently established therapy control systems for time resolved delivery. But since also these novel optimization techniques rely on the validity of the 4DCT, research focusing on alternative 4D imaging technique, such as MRI based 4DCT generation will continue. PMID:24354749

  6. The Advanced Composition Explorer Shock Database and Application to Particle Acceleration Theory

    NASA Technical Reports Server (NTRS)

    Parker, L. Neergaard; Zank, G. P.

    2015-01-01

    The theory of particle acceleration via diffusive shock acceleration (DSA) has been studied in depth by Gosling et al. (1981), van Nes et al. (1984), Mason (2000), Desai et al. (2003), Zank et al. (2006), among many others. Recently, Parker and Zank (2012, 2014) and Parker et al. (2014) using the Advanced Composition Explorer (ACE) shock database at 1 AU explored two questions: does the upstream distribution alone have enough particles to account for the accelerated downstream distribution and can the slope of the downstream accelerated spectrum be explained using DSA? As was shown in this research, diffusive shock acceleration can account for a large population of the shocks. However, Parker and Zank (2012, 2014) and Parker et al. (2014) used a subset of the larger ACE database. Recently, work has successfully been completed that allows for the entire ACE database to be considered in a larger statistical analysis. We explain DSA as it applies to single and multiple shocks and the shock criteria used in this statistical analysis. We calculate the expected injection energy via diffusive shock acceleration given upstream parameters defined from the ACE Solar Wind Electron, Proton, and Alpha Monitor (SWEPAM) data to construct the theoretical upstream distribution. We show the comparison of shock strength derived from diffusive shock acceleration theory to observations in the 50 keV to 5 MeV range from an instrument on ACE. Parameters such as shock velocity, shock obliquity, particle number, and time between shocks are considered. This study is further divided into single and multiple shock categories, with an additional emphasis on forward-forward multiple shock pairs. Finally with regard to forwardforward shock pairs, results comparing injection energies of the first shock, second shock, and second shock with previous energetic population will be given.

  7. The “Puck” energetic charged particle detector: Design, heritage, and advancements

    PubMed Central

    Cohen, I.; Westlake, J. H.; Andrews, G. B.; Brandt, P.; Gold, R. E.; Gkioulidou, M. A.; Hacala, R.; Haggerty, D.; Hill, M. E.; Ho, G. C.; Jaskulek, S. E.; Kollmann, P.; Mauk, B. H.; McNutt, R. L.; Mitchell, D. G.; Nelson, K. S.; Paranicas, C.; Paschalidis, N.; Schlemm, C. E.

    2016-01-01

    Abstract Energetic charged particle detectors characterize a portion of the plasma distribution function that plays critical roles in some physical processes, from carrying the currents in planetary ring currents to weathering the surfaces of planetary objects. For several low‐resource missions in the past, the need was recognized for a low‐resource but highly capable, mass‐species‐discriminating energetic particle sensor that could also obtain angular distributions without motors or mechanical articulation. This need led to the development of a compact Energetic Particle Detector (EPD), known as the “Puck” EPD (short for hockey puck), that is capable of determining the flux, angular distribution, and composition of incident ions between an energy range of ~10 keV to several MeV. This sensor makes simultaneous angular measurements of electron fluxes from the tens of keV to about 1 MeV. The same measurements can be extended down to approximately 1 keV/nucleon, with some composition ambiguity. These sensors have a proven flight heritage record that includes missions such as MErcury Surface, Space ENvironment, GEochemistry, and Ranging and New Horizons, with multiple sensors on each of Juno, Van Allen Probes, and Magnetospheric Multiscale. In this review paper we discuss the Puck EPD design, its heritage, unexpected results from these past missions and future advancements. We also discuss high‐voltage anomalies that are thought to be associated with the use of curved foils, which is a new foil manufacturing processes utilized on recent Puck EPD designs. Finally, we discuss the important role Puck EPDs can potentially play in upcoming missions. PMID:27867799

  8. Filter quality of pleated filter cartridges.

    PubMed

    Chen, Chun-Wan; Huang, Sheng-Hsiu; Chiang, Che-Ming; Hsiao, Ta-Chih; Chen, Chih-Chieh

    2008-04-01

    The performance of dust cartridge filters commonly used in dust masks and in room ventilation depends both on the collection efficiency of the filter material and the pressure drop across the filter. Currently, the optimization of filter design is based only on minimizing the pressure drop at a set velocity chosen by the manufacturer. The collection efficiency, an equally important factor, is rarely considered in the optimization process. In this work, a filter quality factor, which combines the collection efficiency and the pressure drop, is used as the optimization criterion for filter evaluation. Most respirator manufacturers pleat the filter to various extents to increase the filtration area in the limit space within the dust cartridge. Six sizes of filter holders were fabricated to hold just one pleat of filter, simulating six different pleat counts, ranging from 0.5 to 3.33 pleats cm(-1). The possible electrostatic charges on the filter were removed by dipping in isopropyl alcohol, and the air velocity is fixed at 100 cm s(-1). Liquid dicotylphthalate particles generated by a constant output atomizer were used as challenge aerosols to minimize particle loading effects. A scanning mobility particle sizer was used to measure the challenge aerosol number concentrations and size distributions upstream and downstream of the pleated filter. The pressure drop across the filter was monitored by using a calibrated pressure transducer. The results showed that the performance of pleated filters depend not only on the size of the particle but also on the pleat count of the pleated filter. Based on filter quality factor, the optimal pleat count (OPC) is always higher than that based on pressure drop by about 0.3-0.5 pleats cm(-1). For example, the OPC is 2.15 pleats cm(-1) from the standpoint of pressure drop, but for the highest filter quality factor, the pleated filter needed to have a pleat count of 2.65 pleats cm(-1) at particle diameter of 122 nm. From the aspect of

  9. Regenerative particulate filter development

    NASA Technical Reports Server (NTRS)

    Descamp, V. A.; Boex, M. W.; Hussey, M. W.; Larson, T. P.

    1972-01-01

    Development, design, and fabrication of a prototype filter regeneration unit for regenerating clean fluid particle filter elements by using a backflush/jet impingement technique are reported. Development tests were also conducted on a vortex particle separator designed for use in zero gravity environment. A maintainable filter was designed, fabricated and tested that allows filter element replacement without any leakage or spillage of system fluid. Also described are spacecraft fluid system design and filter maintenance techniques with respect to inflight maintenance for the space shuttle and space station.

  10. Application and advantages of novel clay ceramic particles (CCPs) in an up-flow anaerobic bio-filter (UAF) for wastewater treatment.

    PubMed

    Han, Wei; Yue, Qinyan; Wu, Suqing; Zhao, Yaqin; Gao, Baoyu; Li, Qian; Wang, Yan

    2013-06-01

    Utilization of clay ceramic particles (CCPs) as the novel filter media employed in an up-flow anaerobic bio-filter (UAF) was investigated. After a series of tests and operations, CCPs have presented higher total porosity and roughness, meanwhile lower bulk and grain density. When CCPs were utilized as fillers, the reactor had a shorter start up period of 45 days comparing with conventional reactors, and removal rate of chemical oxygen demand (COD) still reached about 76% at a relatively lower temperature during the stable state. In addition, degradation of COD and ammonia nitrogen (NH4-N) at different media height along the reactor was evaluated, and the dates showed that the main reduction process happened within the first 30 cm media height from the bottom flange. Five phases were observed according to different organic loadings during the experiment period, and the results indicated that COD removal increased linearly when the organic loading was increased.

  11. The development of optical microscopy techniques for the advancement of single-particle studies

    SciTech Connect

    Marchuk, Kyle

    2013-05-15

    Single particle orientation and rotational tracking (SPORT) has recently become a powerful optical microscopy tool that can expose many molecular motions. Unfortunately, there is not yet a single microscopy technique that can decipher all particle motions in all environmental conditions, thus there are limitations to current technologies. Within, the two powerful microscopy tools of total internal reflection and interferometry are advanced to determine the position, orientation, and optical properties of metallic nanoparticles in a variety of environments. Total internal reflection is an optical phenomenon that has been applied to microscopy to produce either fluorescent or scattered light. The non-invasive far-field imaging technique is coupled with a near-field illumination scheme that allows for better axial resolution than confocal microscopy and epi-fluorescence microscopy. By controlling the incident illumination angle using total internal reflection fluorescence (TIRF) microscopy, a new type of imaging probe called “non-blinking” quantum dots (NBQDs) were super-localized in the axial direction to sub-10-nm precision. These particles were also used to study the rotational motion of microtubules being propelled by the motor protein kinesin across the substrate surface. The same instrument was modified to function under total internal reflection scattering (TIRS) microscopy to study metallic anisotropic nanoparticles and their dynamic interactions with synthetic lipid bilayers. Utilizing two illumination lasers with opposite polarization directions at wavelengths corresponding to the short and long axis surface plasmon resonance (SPR) of the nanoparticles, both the in-plane and out-of-plane movements of many particles could be tracked simultaneously. When combined with Gaussian point spread function (PSF) fitting for particle super-localization, the binding status and rotational movement could be resolved without degeneracy. TIRS microscopy was also used to

  12. One-dimensional soil temperature simulation with Common Land Model by assimilating in situ observations and MODIS LST with the ensemble particle filter

    NASA Astrophysics Data System (ADS)

    Yu, Zhongbo; Fu, Xiaolei; Luo, Lifeng; Lü, Haishen; Ju, Qin; Liu, Di; Kalin, Dresden A.; Huang, Dui; Yang, Chuanguo; Zhao, Lili

    2014-08-01

    Soil temperature plays an important role in hydrology, agriculture, and meteorology. In order to improve the accuracy of soil temperature simulation, a soil temperature data assimilation system was developed based on the Ensemble Particle Filter (EnPF) and the Common Land Model (CLM), and then applied in the Walnut Gulch Experimental Watershed (WGEW) in Arizona, United States. Surface soil temperature in situ observations and Moderate Resolution Imaging Spectroradiometer Land Surface Temperature (MODIS LST) data were assimilated into the system. In this study, four different assimilation experiments were conducted: (1) assimilating in situ observations of instantaneous surface soil temperature each hour, (2) assimilating in situ observations of instantaneous surface soil temperature once per day, (3) assimilating verified MODIS LST once per day, and (4) assimilating original MODIS LST once per day. These four experiments reflect a transition from high-quality and more frequent in situ observations to lower quality and less frequent remote sensing data in the data assimilation system. The results from these four experiments show that the assimilated results are better than the simulated results without assimilation at all layers except the bottom layer, while the superiority gradually diminishes as the quality and frequency of the observations decrease. This demonstrates that remote sensing data can be assimilated using the ensemble particle filter in poorly gauged catchments to obtain highly accurate soil variables (e.g., soil moisture, soil temperature). Meanwhile, the results also demonstrate that the ensemble particle filter is effective in assimilating soil temperature observations to improve simulations, but the performance of the data assimilation method is affected by the frequency of assimilation and the quality of the input data.

  13. A Dynamic Model for the Interaction Between an Insoluble Particle and an Advancing Solid/Liquid Interface

    NASA Technical Reports Server (NTRS)

    Catalina, A. V.; Mukherjee, S.; Stefanescu, D. M.

    2000-01-01

    Most models that describe the interaction of an insoluble particle with an advancing solid-liquid interface are based on the assumption of steady state. However, as demonstrated by experimental work, the process does not reach steady state until the particle is pushed for a while by the interface. In this work, a dynamic mathematical model was developed. The dynamic model demonstrates that this interaction is essentially non-steady state and that steady state eventually occurs only when solidification is conducted at sub-critical velocities. The model was tested for three systems: aluminum-zirconia particles, succinonitrilepolystyrene particles, and biphenyl-glass particles. The calculated values for critical velocity of the pushing/engulfment transition were in same range with the experimental ones.

  14. Similar cellular effects induced by diesel exhaust particles from a representative diesel vehicle recovered from filters and Standard Reference Material 1650.

    PubMed

    Boland, S; Baeza-Squiban, A; Bonvallot, V; Houcine, O; Pain, C; Meyer, M; Marano, F

    2001-01-01

    Standard reference diesel exhaust particles (DEP) SRM 1650 are often used to evaluate the toxicity of DEP. However, these particles did not necessarily reflect the effects of DEP representative of present diesel automobiles. This study was designed to compare the effects of SRM 1650 to DEP from representative cars (RC-DEP) on airway epithelial cells. Therefore we established a method to recover RC-DEP impacted on filters after emission from diesel automobiles on test beds. Electron microscopy and flow cytometry showed that these two types of particles were phagocytosed to the same extent by epithelial cells. This phagocytosis is not dependent on the adsorbed organic compounds in contrast to the cytotoxic effect evaluated by measurements of LDH release. This is emphasized by the fact that RC-DEP equipped with an oxidation catalyst are less cytotoxic than particles from a non-equipped vehicle or SRM 1650. This type of catalyst also reduces significantly the release of GM-CSF by bronchial epithelial cells. We have shown in the present paper that SRM 1650 may be used as a surrogate of DEP. However, exhaust gas post-treatment devices of current diesel automobiles reduce the cytotoxicity as well as the inflammatory response of these particles.

  15. Effects of biodiesel, engine load and diesel particulate filter on nonvolatile particle number size distributions in heavy-duty diesel engine exhaust.

    PubMed

    Young, Li-Hao; Liou, Yi-Jyun; Cheng, Man-Ting; Lu, Jau-Huai; Yang, Hsi-Hsien; Tsai, Ying I; Wang, Lin-Chi; Chen, Chung-Bang; Lai, Jim-Shoung

    2012-01-15

    Diesel engine exhaust contains large numbers of submicrometer particles that degrade air quality and human health. This study examines the number emission characteristics of 10-1000 nm nonvolatile particles from a heavy-duty diesel engine, operating with various waste cooking oil biodiesel blends (B2, B10 and B20), engine loads (0%, 25%, 50% and 75%) and a diesel oxidation catalyst plus diesel particulate filter (DOC+DPF) under steady modes. For a given load, the total particle number concentrations (N(TOT)) decrease slightly, while the mode diameters show negligible changes with increasing biodiesel blends. For a given biodiesel blend, both the N(TOT) and mode diameters increase modestly with increasing load of above 25%. The N(TOT) at idle are highest and their size distributions are strongly affected by condensation and possible nucleation of semivolatile materials. Nonvolatile cores of diameters less than 16 nm are only observed at idle mode. The DOC+DPF shows remarkable filtration efficiency for both the core and soot particles, irrespective of the biodiesel blend and engine load under study. The N(TOT) post the DOC+DPF are comparable to typical ambient levels of ≈ 10(4)cm(-3). This implies that, without concurrent reductions of semivolatile materials, the formation of semivolatile nucleation mode particles post the after treatment is highly favored.

  16. Effect of Drive Cycle and Gasoline Particulate Filter on the Size and Morphology of Soot Particles Emitted from a Gasoline-Direct-Injection Vehicle.

    PubMed

    Saffaripour, Meghdad; Chan, Tak W; Liu, Fengshan; Thomson, Kevin A; Smallwood, Gregory J; Kubsh, Joseph; Brezny, Rasto

    2015-10-06

    The size and morphology of particulate matter emitted from a light-duty gasoline-direct-injection (GDI) vehicle, over the FTP-75 and US06 transient drive cycles, have been characterized by transmission-electron-microscope (TEM) image analysis. To investigate the impact of gasoline particulate filters on particulate-matter emission, the results for the stock-GDI vehicle, that is, the vehicle in its original configuration, have been compared to the results for the same vehicle equipped with a catalyzed gasoline particulate filter (GPF). The stock-GDI vehicle emits graphitized fractal-like aggregates over all driving conditions. The mean projected area-equivalent diameter of these aggregates is in the 78.4-88.4 nm range and the mean diameter of primary particles varies between 24.6 and 26.6 nm. Post-GPF particles emitted over the US06 cycle appear to have an amorphous structure, and a large number of nucleation-mode particles, depicted as low-contrast ultrafine droplets, are observed in TEM images. This indicates the emission of a substantial amount of semivolatile material during the US06 cycle, most likely generated by the incomplete combustion of accumulated soot in the GPF during regeneration. The size of primary particles and soot aggregates does not vary significantly by implementing the GPF over the FTP-75 cycle; however, particles emitted by the GPF-equipped vehicle over the US06 cycle are about 20% larger than those emitted by the stock-GDI vehicle. This may be attributed to condensation of large amounts of organic material on soot aggregates. High-contrast spots, most likely solid nonvolatile cores, are observed within many of the nucleation-mode particles emitted over the US06 cycle by the GPF-equipped vehicle. These cores are either generated inside the engine or depict incipient soot particles which are partially carbonized in the exhaust line. The effect of drive cycle and the GPF on the fractal parameters of particles, such as fractal dimension and

  17. Moving granular-bed filter development program. Topical report

    SciTech Connect

    Newby, R.A.; Yang, W.C.; Smeltzer, E.E.; Lippert, T.E.

    1994-04-01

    Advanced, coal-based, power plants, such as IGCC and Advanced-PFBC, are currently nearing commercial demonstration. These power plant technologies require hot gas filtration as part of their gas cleaning trains. Ceramic barrier filters are the major filter candidates being developed for these hot gas cleaning applications. While ceramic barrier filters achieve high levels of particle removal, concerns exist for their reliability and operability in these applications. An alternative hot gas filtration technology is the moving granular bed filter. An advanced, moving granular bed filter has been conceived, and early development activities performed by the Westinghouse Electric Corporation, Science and Technology Center. This document reports on the Base Contract tasks performed to resolve the barrier technical issues for this technology. The concept, the Standleg Moving Granular Bed Filter (SMGBF) has a concurrent downward, gas and bed media flow configuration that results in simplified features and improved scaleup feasibility compared to alternative designs. Two modes of bed media operation were assessed in the program: once-through using pelletized power plant waste as bed media, and recycle of bed media via standleg and pneumatic transport techniques. Cold Model testing; high-temperature, high-pressure testing; and pelletization testing using advanced power plant wastes, have been conducted in the program. A commercial, economic assessment of the SMGBF technology was performed for IGCC and Advanced-PFBC applications. The evaluation shows that the barrier technical issues can be resolved, and that the technology is potentially competitive with ceramic barrier filters.

  18. Ceramic filters

    SciTech Connect

    Holmes, B.L.; Janney, M.A.

    1995-12-31

    Filters were formed from ceramic fibers, organic fibers, and a ceramic bond phase using a papermaking technique. The distribution of particulate ceramic bond phase was determined using a model silicon carbide system. As the ceramic fiber increased in length and diameter the distance between particles decreased. The calculated number of particles per area showed good agreement with the observed value. After firing, the papers were characterized using a biaxial load test. The strength of papers was proportional to the amount of bond phase included in the paper. All samples exhibited strain-tolerant behavior.

  19. A Method for Consensus Reaching in Product Kansei Evaluation Using Advanced Particle Swarm Optimization

    PubMed Central

    2017-01-01

    Consumers' opinions toward product design alternatives are often subjective and perceptual, which reflect their perception about a product and can be described using Kansei adjectives. Therefore, Kansei evaluation is often employed to determine consumers' preference. However, how to identify and improve the reliability of consumers' Kansei evaluation opinions toward design alternatives has an important role in adding additional insurance and reducing uncertainty to successful product design. To solve this problem, this study employs a consensus model to measure consistence among consumers' opinions, and an advanced particle swarm optimization (PSO) algorithm combined with Linearly Decreasing Inertia Weight (LDW) method is proposed for consensus reaching by minimizing adjustment of consumers' opinions. Furthermore, the process of the proposed method is presented and the details are illustrated using an example of electronic scooter design evaluation. The case study reveals that the proposed method is promising for reaching a consensus through searching optimal solutions by PSO and improving the reliability of consumers' evaluation opinions toward design alternatives according to Kansei indexes. PMID:28316619

  20. Recent advances in the modeling of plasmas with the Particle-In-Cell methods

    NASA Astrophysics Data System (ADS)

    Vay, Jean-Luc; Lehe, Remi; Vincenti, Henri; Godfrey, Brendan; Lee, Patrick; Haber, Irv

    2015-11-01

    The Particle-In-Cell (PIC) approach is the method of choice for self-consistent simulations of plasmas from first principles. The fundamentals of the PIC method were established decades ago but improvements or variations are continuously being proposed. We report on several recent advances in PIC related algorithms, including: (a) detailed analysis of the numerical Cherenkov instability and its remediation, (b) analytic pseudo-spectral electromagnetic solvers in Cartesian and cylindrical (with azimuthal modes decomposition) geometries, (c) arbitrary-order finite-difference and generalized pseudo-spectral Maxwell solvers, (d) novel analysis of Maxwell's solvers' stencil variation and truncation, in application to domain decomposition strategies and implementation of Perfectly Matched Layers in high-order and pseudo-spectral solvers. Work supported by US-DOE Contracts DE-AC02-05CH11231 and the US-DOE SciDAC program ComPASS. Used resources of NERSC, supported by US-DOE Contract DE-AC02-05CH11231.

  1. A Method for Consensus Reaching in Product Kansei Evaluation Using Advanced Particle Swarm Optimization.

    PubMed

    Yang, Yan-Pu

    2017-01-01

    Consumers' opinions toward product design alternatives are often subjective and perceptual, which reflect their perception about a product and can be described using Kansei adjectives. Therefore, Kansei evaluation is often employed to determine consumers' preference. However, how to identify and improve the reliability of consumers' Kansei evaluation opinions toward design alternatives has an important role in adding additional insurance and reducing uncertainty to successful product design. To solve this problem, this study employs a consensus model to measure consistence among consumers' opinions, and an advanced particle swarm optimization (PSO) algorithm combined with Linearly Decreasing Inertia Weight (LDW) method is proposed for consensus reaching by minimizing adjustment of consumers' opinions. Furthermore, the process of the proposed method is presented and the details are illustrated using an example of electronic scooter design evaluation. The case study reveals that the proposed method is promising for reaching a consensus through searching optimal solutions by PSO and improving the reliability of consumers' evaluation opinions toward design alternatives according to Kansei indexes.

  2. Particle-filtering-based failure prognosis via sigma-points: Application to Lithium-Ion battery State-of-Charge monitoring

    NASA Astrophysics Data System (ADS)

    Acuña, David E.; Orchard, Marcos E.

    2017-02-01

    This paper presents a novel prognostic method that allows a proper characterization of the uncertainty associated with the evolution in time of nonlinear dynamical systems. The method assumes a state-space representation of the system, as well as the availability of particle-filtering-based estimates of the state posterior density at the moment in which the prognostic algorithm is executed. Our proposal significantly improves all particle-filtering-based prognosis frameworks currently available in two main aspects. First, it provides a correction for the expression that is used for the computation of the Time-of-Failure (ToF) probability mass function in the context of online monitoring schemes. Secondly, it presents a method for improved characterization of the tails of the ToF probability mass function via sequential propagation of sigma-points and the computation of Gaussian Mixture Models (GMMs). The proposed algorithm is tested and validated using experimental data related to the problem of Lithium-Ion battery State-of-Charge prognosis.

  3. Aerosol-phase Activity of Iodine Captured from a Triiodide Resin Filter on Fine Particles Containing an Infectious Virus

    DTIC Science & Technology

    2015-01-01

    phage, filter, infection , iodine, triiodide U U U SAR 6 Joseph D. Wander 850 283-6240 Reset ORIGINAL ARTICLE Aerosol-phase activity of iodine captured... infections in enclosed areas. Introduction Recurring reminders of the risk of respiratory infection by airborne pathogenic microbes include malicious...enhancing protection against the airborne infections by the integration of anti microbials such as silver (Foss Manufacturing Company, Inc. 2004; Mia

  4. Advances in analytical methods and occurrence of organic UV-filters in the environment--A review.

    PubMed

    Ramos, Sara; Homem, Vera; Alves, Arminda; Santos, Lúcia

    2015-09-01

    UV-filters are a group of compounds designed mainly to protect skin against UVA and UVB radiation, but they are also included in plastics, furniture, etc., to protect products from light damage. Their massive use in sunscreens for skin protection has been increasing due to the awareness of the chronic and acute effects of UV radiation. Some organic UV-filters have raised significant concerns in the past few years for their continuous usage, persistent input and potential threat to ecological environment and human health. UV-filters end up in wastewater and because wastewater treatment plants are not efficient in removing them, lipophilic compounds tend to sorb onto sludge and hydrophilics end up in river water, contaminating the existing biota. To better understand the risk associated with UV-filters in the environment a thorough review regarding their physicochemical properties, toxicity and environmental degradation, analytical methods and their occurrence was conducted. Higher UV-filter concentrations were found in rivers, reaching 0.3mg/L for the most studied family, the benzophenone derivatives. Concentrations in the ng to μg/L range were also detected for the p-aminobenzoic acid, cinnamate, crylene and benzoyl methane derivatives in lake and sea water. Although at lower levels (few ng/L), UV-filters were also found in tap and groundwater. Swimming pool water is also a sink for UV-filters and its chlorine by-products, at the μg/L range, highlighting the benzophenone and benzimidazole derivatives. Soils and sediments are not frequently studied, but concentrations in the μg/L range have already been found especially for the benzophenone and crylene derivatives. Aquatic biota is frequently studied and UV-filters are found in the ng/g-dw range with higher values for fish and mussels. It has been concluded that more information regarding UV-filter degradation studies both in water and sediments is necessary and environmental occurrences should be monitored more

  5. Effect of advanced aftertreatment for PM and NOx reduction on heavy-duty diesel engine ultrafine particle emissions.

    PubMed

    Herner, Jorn Dinh; Hu, Shaohua; Robertson, William H; Huai, Tao; Chang, M-C Oliver; Rieger, Paul; Ayala, Alberto

    2011-03-15

    Four heavy-duty and medium-duty diesel vehicles were tested in six different aftertreament configurations using a chassis dynamometer to characterize the occurrence of nucleation (the conversion of exhaust gases to particles upon dilution). The aftertreatment included four different diesel particulate filters and two selective catalytic reduction (SCR) devices. All DPFs reduced the emissions of solid particles by several orders of magnitude, but in certain cases the occurrence of a volatile nucleation mode could increase total particle number emissions. The occurrence of a nucleation mode could be predicted based on the level of catalyst in the aftertreatment, the prevailing temperature in the aftertreatment, and the age of the aftertreatment. The particles measured during nucleation had a high fraction of sulfate, up to 62% of reconstructed mass. Additionally the catalyst reduced the toxicity measured in chemical and cellular assays suggesting a pathway for an inverse correlation between particle number and toxicity. The results have implications for exposure to and toxicity of diesel PM.

  6. Sub-micron filter

    DOEpatents

    Tepper, Frederick; Kaledin, Leonid

    2009-10-13

    Aluminum hydroxide fibers approximately 2 nanometers in diameter and with surface areas ranging from 200 to 650 m.sup.2/g have been found to be highly electropositive. When dispersed in water they are able to attach to and retain electronegative particles. When combined into a composite filter with other fibers or particles they can filter bacteria and nano size particulates such as viruses and colloidal particles at high flux through the filter. Such filters can be used for purification and sterilization of water, biological, medical and pharmaceutical fluids, and as a collector/concentrator for detection and assay of microbes and viruses. The alumina fibers are also capable of filtering sub-micron inorganic and metallic particles to produce ultra pure water. The fibers are suitable as a substrate for growth of cells. Macromolecules such as proteins may be separated from each other based on their electronegative charges.

  7. Hybrid Filter Membrane

    NASA Technical Reports Server (NTRS)

    Laicer, Castro; Rasimick, Brian; Green, Zachary

    2012-01-01

    Cabin environmental control is an important issue for a successful Moon mission. Due to the unique environment of the Moon, lunar dust control is one of the main problems that significantly diminishes the air quality inside spacecraft cabins. Therefore, this innovation was motivated by NASA s need to minimize the negative health impact that air-suspended lunar dust particles have on astronauts in spacecraft cabins. It is based on fabrication of a hybrid filter comprising nanofiber nonwoven layers coated on porous polymer membranes with uniform cylindrical pores. This design results in a high-efficiency gas particulate filter with low pressure drop and the ability to be easily regenerated to restore filtration performance. A hybrid filter was developed consisting of a porous membrane with uniform, micron-sized, cylindrical pore channels coated with a thin nanofiber layer. Compared to conventional filter media such as a high-efficiency particulate air (HEPA) filter, this filter is designed to provide high particle efficiency, low pressure drop, and the ability to be regenerated. These membranes have well-defined micron-sized pores and can be used independently as air filters with discreet particle size cut-off, or coated with nanofiber layers for filtration of ultrafine nanoscale particles. The filter consists of a thin design intended to facilitate filter regeneration by localized air pulsing. The two main features of this invention are the concept of combining a micro-engineered straight-pore membrane with nanofibers. The micro-engineered straight pore membrane can be prepared with extremely high precision. Because the resulting membrane pores are straight and not tortuous like those found in conventional filters, the pressure drop across the filter is significantly reduced. The nanofiber layer is applied as a very thin coating to enhance filtration efficiency for fine nanoscale particles. Additionally, the thin nanofiber coating is designed to promote capture of

  8. Investigating the Performance of Some Tracking Filter Schema for the Advanced Shipboard Command and Control Technology (ASCACT) Project

    DTIC Science & Technology

    2000-10-01

    tracking performance of the 3CVP AR track filter is compared with: 1) an adaptive single motion model Kalman filter (ASMMKF); 2) an IMM algorithm using...probleme complexe qui continue d’attirer !’attention de nombreux chercheurs depuis plusieurs annees. On a etabli que le filtrage de Kalman de type modeles...8217’ utilise trois filtres ayant des modeles differents de v1tesses constantes (appeles ŗCVPAR") et un detecteur de manoeuvre. L’estime est choisi par le

  9. Estimation of ice activation parameters within a particle tracking Lagrangian cloud model using the ensemble Kalman filter to match ISCDAC golden case observations

    NASA Astrophysics Data System (ADS)

    Reisner, J. M.; Dubey, M. K.

    2010-12-01

    To both quantify and reduce uncertainty in ice activation parameterizations for stratus clouds occurring in the temperature range between -5 to -10 C ensemble simulations of an ISDAC golden case have been conducted. To formulate the ensemble, three parameters found within an ice activation model have been sampled using a Latin hypercube technique over a parameter range that induces large variability in both number and mass of ice. The ice activation model is contained within a Lagrangian cloud model that simulates particle number as a function of radius for cloud ice, snow, graupel, cloud, and rain particles. A unique aspect of this model is that it produces very low levels of numerical diffusion that enable the model to accurately resolve the sharp cloud edges associated with the ISDAC stratus deck. Another important aspect of the model is that near the cloud edges the number of particles can be significantly increased to reduce sampling errors and accurately resolve physical processes such as collision-coalescence that occur in this region. Thus, given these relatively low numerical errors, as compared to traditional bin models, the sensitivity of a stratus deck to changes in parameters found within the activation model can be examined without fear of numerical contamination. Likewise, once the ensemble has been completed, ISDAC observations can be incorporated into a Kalman filter to optimally estimate the ice activation parameters and reduce overall model uncertainty. Hence, this work will highlight the ability of an ensemble Kalman filter system coupled to a highly accurate numerical model to estimate important parameters found within microphysical parameterizations containing high uncertainty.

  10. Characterization and Failure Analysis of Ceramic Filters Utilized for Emission Control Coal Gasification

    SciTech Connect

    Daniel Mei; Jianren Zhou; Ziaul Huque

    1998-03-01

    Advanced integrated gasification combined cycle (IGCC) and pressurized fluidized bed combustion (PFBC) power system requires both hot gas desulfurization and particulate filtration to improve system thermal efficiency and overall performance. Therefore, effective high temperature ceramic filters are indispensable key component in both of the advanced IGCC and PFBC coal based power systems to perform hot gas cleanup work. To meet the environmental particulate emission requirements and improve thermal efficiency, ceramic filters are mainly utilized to cleanup the hot gas particulate to protect downstream heat exchanger and gas turbine components from fouling and corrosion. The mechanical integrity of ceramic filters and an efficient dust cake removal system are the key issues for hot gas cleanup systems. The filters must survive combined stresses due to mechanical, thermal, chemical and steam attack throughout normal operations (cold back pulse cleaning jets), unexpected excessive ash accumulation, and the start up and shut down conditions. To evaluate the design and performance of ceramic filters, different long term filter testing programs were conducted. To fulfill this purpose, two Advanced Particle Filter (APF) systems were complete at Tidd PFBC Demonstration Plant, in Brilliant, Ohio in late 1990 as part of the Department of Energy's (DOE) Clean Coal Technology Program. But the most undesirable thing ever happened was the sudden functional and physical failures of filters prior to its designed life time. In Tidd APF filter vessel, twenty eight (28) filters failed one time. Significant research effort has been carried out to find out the causes that led to the early failure of filters. In this work, the studies are emphasized on the possible failure causes analysis of rigid ceramic candle filters. The objectives of this program were to provide an systematic study on the characterization of filters, material laboratory analysis on filter micro-structure, the dust

  11. Advanced multi-frequency radar: Design, preliminary measurements and particle size distribution retrieval

    NASA Astrophysics Data System (ADS)

    Majurec, Ninoslav

    In the spring of 2001 the Microwave Remote Sensing Laboratory (MIRSL) at the University of Massachusetts began the development of an advanced Multi-Frequency Radar (AMFR) system for studying clouds and precipitation. This mobile radar was designed to consist of three polarimetric Doppler subsystems operating at Ku-band (13.4 GHz), Ka-band (35.6 GHz) and W-band (94.92 GHz). This combination of frequency bands allows a measurement of a wide range of atmospheric targets ranging from weakly reflecting clouds to strong precipitation. The antenna beamwidths at each frequency were intentionally matched, ensuring consistent sampling volume. Multi-frequency radar remote sensing techniques are not widely used because few multi-frequency radars are available to the science community. One exception is the 33 GHz/95 GHz UMass Cloud Profiling Radar System (CPRS), which AMFR is intended to replace. AMFR's multi-parameter capabilities are designed for characterizing the complex microphysics of layer clouds and precipitation processes in winter storms. AMFR will also play an important role in developing algorithms and validating measurements for an upcoming generation of space-borne radars. The frequency bands selected for AMFR match those of several sensors that have been deployed or are under development. These include the Japanese Aerospace Exploration Agencies (JAXA's) Tropical Rainfall Measuring Mission (TRMM) satellite Ku-band (13 GHz) radar, the CloudSat W-band (95 GHz) radar, and the Global Precipitation Mission (GPM) satellite radars at Ku-band and Ka-band. This dissertation describes the AMFR hardware design and development. Compared to CPRS, the addition of one extra frequency band (Ku) will extend AMFR's measurement capabilities towards the larger particle sizes (precipitation). AMFR's design is based around high-power klystron amplifiers. This ensures complete coherency (CPRS uses magnetrons and coherent-on-receive technique). The partial loss in sensitivity due to

  12. Anti-clogging filter system

    DOEpatents

    Brown, Erik P.

    2015-05-19

    An anti-clogging filter system for filtering a fluid containing large particles and small particles includes an enclosure with at least one individual elongated tubular filter element in the enclosure. The individual elongated tubular filter element has an internal passage, a closed end, an open end, and a filtering material in or on the individual elongated tubular filter element. The fluid travels through the open end of the elongated tubular element and through the internal passage and through the filtering material. An anti-clogging element is positioned on or adjacent the individual elongated tubular filter element and provides a fluid curtain that preferentially directs the larger particulates to one area of the filter material allowing the remainder of the filter material to remain more efficient.

  13. Impact of supplemental firing of tire-derived fuel (TDF) on mercury species and mercury capture with the advanced hybrid filter in a western subbituminous coal flue gas

    SciTech Connect

    Ye Zhuang; Stanley J. Miller

    2006-05-15

    Pilot-scale experimental studies were carried out to evaluate the impacts of cofiring tire-derived fuel and a western subbituminous coal on mercury species in flue gas. Mercury samples were collected at the inlet and outlet of the Advanced Hybrid filter to determine mercury concentrations in the flue gas with and without TDF cofiring, respectively. Cofiring of TDF with a subbituminous coal had a significant effect on mercury speciation in the flue gas. With 100% coal firing, there was only 16.8% oxidized mercury in the flue gas compared to 47.7% when 5% TDF (mass basis) was fired and 84.8% when 10% TDF was cofired. The significantly enhanced mercury oxidation may be the result of additional homogeneous gas reactions between Hg{sup 0} and the reactive chlorine generated in the TDF-cofiring flue gas and the in situ improved reactivity of unburned carbon in ash by the reactive chlorine species. Although the cofiring of TDF demonstrated limited improvement on mercury-emission control with the Advanced Hybrid filter, it proved to be a very cost-effective mercury control approach for power plants equipped with wet or dry flue gas desulfurization (FGD) systems because of the enhanced mercury oxidation. 15 refs., 4 figs., 4 tabs.

  14. A new coincidence model for single particle counters, Part II: Advances and applications.

    PubMed

    Knapp, J Z; Lieberman, A; Abramson, L R

    1994-01-01

    Accuracy, acceptance limits and methods for U.S.P. (788) contaminating particle assays published in the XXII Revision are refined in U.S.P. XXIII. In both Revisions, although different numerical values and methods are employed, particle contamination limits remain constants for all S.V.I. container volumes. The effect of this quality standard is high particle concentration acceptance limits in the smallest S.V.I. container sizes. The effect of these high concentrations is to introduce both undercount errors and false counts into U.S.P. (788) SVI contaminating particle assays. There is general agreement that the count of high concentrations of particles by a single particle light extinction counter result in an increase of the average size of the distribution of particles reported and a decrease in their total number. The error mechanism is termed "signal coincidence." Understanding and control of both these problems is unified with the introduction of the count efficiency parameter. Part I of this paper makes available two core concepts with which evaluation and control of coincidence error in single particle counters can be accurately quantified. These two core concepts are the "Particle Triggered Poisson Model," a new more accurate statistical model of the particle counting process and a concentration measure that includes the effect of particle size on the counting capability of a detector. Use of these concepts make it possible to evaluate particle detector count efficiency capability from experimental data of the coincidence effect. This is an application paper. It combines the theory in the Part I paper with the replicability of particle counters into a simple test protocol. The test results can be used to calculate a contour of particle size and count within which both undercount errors and the introduction of false counts into U.S.P. (788) particle assays are controlled. From the data analyzed it can be seen that any single particle size test cannot

  15. International journal of computational fluid dynamics real-time prediction of unsteady flow based on POD reduced-order model and particle filter

    NASA Astrophysics Data System (ADS)

    Kikuchi, Ryota; Misaka, Takashi; Obayashi, Shigeru

    2016-04-01

    An integrated method consisting of a proper orthogonal decomposition (POD)-based reduced-order model (ROM) and a particle filter (PF) is proposed for real-time prediction of an unsteady flow field. The proposed method is validated using identical twin experiments of an unsteady flow field around a circular cylinder for Reynolds numbers of 100 and 1000. In this study, a PF is employed (ROM-PF) to modify the temporal coefficient of the ROM based on observation data because the prediction capability of the ROM alone is limited due to the stability issue. The proposed method reproduces the unsteady flow field several orders faster than a reference numerical simulation based on Navier-Stokes equations. Furthermore, the effects of parameters, related to observation and simulation, on the prediction accuracy are studied. Most of the energy modes of the unsteady flow field are captured, and it is possible to stably predict the long-term evolution with ROM-PF.

  16. Use of advanced particle methods in modeling space propulsion and its supersonic expansions

    NASA Astrophysics Data System (ADS)

    Borner, Arnaud

    This research discusses the use of advanced kinetic particle methods such as Molecular Dynamics (MD) and direct simulation Monte Carlo (DSMC) to model space propulsion systems such as electrospray thrusters and their supersonic expansions. MD simulations are performed to model an electrospray thruster for the ionic liquid (IL) EMIM--BF4 using coarse-grained (CG) potentials. The model is initially featuring a constant electric field applied in the longitudinal direction. Two coarse-grained potentials are compared, and the effective-force CG (EFCG) potential is found to predict the formation of the Taylor cone, the cone-jet, and other extrusion modes for similar electric fields and mass flow rates observed in experiments of a IL fed capillary-tip-extractor system better than the simple CG potential. Later, one-dimensional and fully transient three-dimensional electric fields, the latter solving Poisson's equation to take into account the electric field due to space charge at each timestep, are computed by coupling the MD model to a Poisson solver. It is found that the inhomogeneous electric field as well as that of the IL space-charge improve agreement between modeling and experiment. The boundary conditions (BCs) are found to have a substantial impact on the potential and electric field, and the tip BC is introduced and compared to the two previous BCs, named plate and needle, showing good improvement by reducing unrealistically high radial electric fields generated in the vicinity of the capillary tip. The influence of the different boundary condition models on charged species currents as a function of the mass flow rate is studied, and it is found that a constant electric field model gives similar agreement to the more rigorous and computationally expensive tip boundary condition at lower flow rates. However, at higher mass flow rates the MD simulations with the constant electric field produces extruded particles with higher Coulomb energy per ion, consistent with

  17. Heavy Charged Particle Radiobiology: Using Enhanced Biological Effectiveness and Improved Beam Focusing to Advance Cancer Therapy

    PubMed Central

    Allen, Christopher; Borak, Thomas B.; Tsujii, Hirohiko; Nickoloff, Jac A.

    2011-01-01

    Ionizing radiation causes many types of DNA damage, including base damage and single- and double-strand breaks. Photons, including X-rays and γ-rays, are the most widely used type of ionizing radiation in radiobiology experiments, and in radiation cancer therapy. Charged particles, including protons and carbon ions, are seeing increased use as an alternative therapeutic modality. Although the facilities needed to produce high energy charged particle beams are more costly than photon facilities, particle therapy has shown improved cancer survival rates, reflecting more highly focused dose distributions and more severe DNA damage to tumor cells. Despite early successes of charged particle radiotherapy, there is room for further improvement, and much remains to be learned about normal and cancer cell responses to charged particle radiation. PMID:21376738

  18. Heavy charged particle radiobiology: using enhanced biological effectiveness and improved beam focusing to advance cancer therapy.

    PubMed

    Allen, Christopher; Borak, Thomas B; Tsujii, Hirohiko; Nickoloff, Jac A

    2011-06-03

    Ionizing radiation causes many types of DNA damage, including base damage and single- and double-strand breaks. Photons, including X-rays and γ-rays, are the most widely used type of ionizing radiation in radiobiology experiments, and in radiation cancer therapy. Charged particles, including protons and carbon ions, are seeing increased use as an alternative therapeutic modality. Although the facilities needed to produce high energy charged particle beams are more costly than photon facilities, particle therapy has shown improved cancer survival rates, reflecting more highly focused dose distributions and more severe DNA damage to tumor cells. Despite early successes of charged particle radiotherapy, there is room for further improvement, and much remains to be learned about normal and cancer cell responses to charged particle radiation.

  19. Ceramic fiber filter technology

    SciTech Connect

    Holmes, B.L.; Janney, M.A.

    1996-06-01

    Fibrous filters have been used for centuries to protect individuals from dust, disease, smoke, and other gases or particulates. In the 1970s and 1980s ceramic filters were developed for filtration of hot exhaust gases from diesel engines. Tubular, or candle, filters have been made to remove particles from gases in pressurized fluidized-bed combustion and gasification-combined-cycle power plants. Very efficient filtration is necessary in power plants to protect the turbine blades. The limited lifespan of ceramic candle filters has been a major obstacle in their development. The present work is focused on forming fibrous ceramic filters using a papermaking technique. These filters are highly porous and therefore very lightweight. The papermaking process consists of filtering a slurry of ceramic fibers through a steel screen to form paper. Papermaking and the selection of materials will be discussed, as well as preliminary results describing the geometry of papers and relative strengths.

  20. The Interaction Between an Insoluble Particle and an Advancing Solid/Liquid Interface: Micro-Gravity Experiments and Theoretical Developments

    NASA Technical Reports Server (NTRS)

    Catalina, Adrian V.; Ssen, Subhayu; Stefanescu, Doru M.

    2003-01-01

    The interaction of an insoluble particle with an advancing solid/liquid interface (SLI) has been a subject of investigation for the past four decades. While the original interest stemmed from geology applications (e.g., frost heaving in soil), researchers soon realized that the complex science associated with such an interaction is relevant to many other scientific fields encompassing metal matrix composites (MMCs), high temperature superconductors, inclusion management in steel, growth of monotectics, and preservation of biological cells. During solidification of a liquid containing an insoluble particle, three distinct interaction phenomena have been experimentally observed: instantaneous engulfment of the particle, continuous pushing, and particle pushing followed by engulfment. It was also observed that for given experimental conditions and particle size there is a critical solidification velocity, V(sub cr), above which a particle is engulfed. During solidification of MMCs pushing leads to particle agglomeration at the grain boundaries and this has detrimental effects on mechanical properties of the casting. Consequently, the process must be designed for instantaneous engulfment to occur. This implies the development of accurate theoretical models to predict V(sub cr), and perform benchmark experiments to test the validity of such models. Although considerable progress has been made in understanding the pushing/engulfment phenomenon (PEP), its quantification in terms of the material and processing parameters remains a focus of research. Since natural convection currents occurring during terrestrial solidification experiments complicate the study of PEP, execution of experiments on the International Space Station (ISS) has been approved and funded by NASA. Extensive terrestrial (1g) experiments and preliminary micro-gravity (mu g) experiments on two space shuttle missions have been conducted in preparation for future experiments on the ISS. The investigated

  1. Nonlinear Attitude Filtering Methods

    NASA Technical Reports Server (NTRS)

    Markley, F. Landis; Crassidis, John L.; Cheng, Yang

    2005-01-01

    This paper provides a survey of modern nonlinear filtering methods for attitude estimation. Early applications relied mostly on the extended Kalman filter for attitude estimation. Since these applications, several new approaches have been developed that have proven to be superior to the extended Kalman filter. Several of these approaches maintain the basic structure of the extended Kalman filter, but employ various modifications in order to provide better convergence or improve other performance characteristics. Examples of such approaches include: filter QUEST, extended QUEST, the super-iterated extended Kalman filter, the interlaced extended Kalman filter, and the second-order Kalman filter. Filters that propagate and update a discrete set of sigma points rather than using linearized equations for the mean and covariance are also reviewed. A two-step approach is discussed with a first-step state that linearizes the measurement model and an iterative second step to recover the desired attitude states. These approaches are all based on the Gaussian assumption that the probability density function is adequately specified by its mean and covariance. Other approaches that do not require this assumption are reviewed, including particle filters and a Bayesian filter based on a non-Gaussian, finite-parameter probability density function on SO(3). Finally, the predictive filter, nonlinear observers and adaptive approaches are shown. The strengths and weaknesses of the various approaches are discussed.

  2. Cell toxicity and oxidative potential of engine exhaust particles: impact of using particulate filter or biodiesel fuel blend.

    PubMed

    Gerlofs-Nijland, Miriam E; Totlandsdal, Annike I; Tzamkiozis, Theodoros; Leseman, Daan L A C; Samaras, Zissis; Låg, Marit; Schwarze, Per; Ntziachristos, Leonidas; Cassee, Flemming R

    2013-06-04

    The link between emissions of vehicular particulate matter (PM) and adverse health effects is well established. However, the influence of new emission control technologies and fuel types on both PM emissions and health effects has been less well investigated. We examined the health impact of PM emissions from two vehicles equipped with or without a diesel particulate filter (DPF). Both vehicles were powered either with diesel (B0) or a 50% v/v biodiesel blend (B50). The DPF effectively decreased PM mass emissions (∼85%), whereas the fuel B50 without DPF lead to less reduction (∼50%). The hazard of PM per unit distance driven was decreased for the DPF-equipped vehicle as indicated by a reduced cytotoxicity, oxidative, and pro-inflammatory potential. This was not evident and even led to an increase when the hazard was expressed on a per unit of mass basis. In general, the PM oxidative potential was similar or reduced for the B50 compared to the B0 powered vehicle. However, the use of B50 resulted in increased cytotoxicity and IL-6 release in BEAS-2B cells irrespective of the expression metric. This study shows that PM mass reduction achieved by the use of B50 will not necessarily decrease the hazard of engine emissions, while the application of a DPF has a beneficial effect on both PM mass emission and PM hazard.

  3. Durability of ceramic filters

    SciTech Connect

    Alvin, M.A.; Tressler, R.E.; Lippert, T.E.; Diaz, E.S.; Smeltzer, E.E.

    1994-10-01

    The objectives of this program are to identify the potential long-term thermal/chemical effects that advanced coal-based power generating systems have on the stability of porous ceramic filter materials, as well as to assess the influence of these effects on filter operating performance and life.

  4. Regression modeling of particle size distributions in urban storm water: advancements through improved sample collection methods

    USGS Publications Warehouse

    Fienen, Michael N.; Selbig, William R.

    2012-01-01

    A new sample collection system was developed to improve the representation of sediment entrained in urban storm water by integrating water quality samples from the entire water column. The depth-integrated sampler arm (DISA) was able to mitigate sediment stratification bias in storm water, thereby improving the characterization of suspended-sediment concentration and particle size distribution at three independent study locations. Use of the DISA decreased variability, which improved statistical regression to predict particle size distribution using surrogate environmental parameters, such as precipitation depth and intensity. The performance of this statistical modeling technique was compared to results using traditional fixed-point sampling methods and was found to perform better. When environmental parameters can be used to predict particle size distributions, environmental managers have more options when characterizing concentrations, loads, and particle size distributions in urban runoff.

  5. Advances in Automated QA/QC for TRISO Fuel Particle Production

    SciTech Connect

    Hockey, Ronald L.; Bond, Leonard J.; Batishko, Charles R.; Gray, Joseph N.; Saurwein, John J.; Lowden, Richard A.

    2004-06-30

    Fuel in most Generation IV reactor designs typically encompasses billions of the TRISO particles. Present day QA/QC methods, done manually and in many cases destructively, cannot economically test a statistically significant fraction of the large number of the individual fuel particles required. Fully automated inspection technologies are essential to economical TRISO fuel particle production. A combination of in-line nondestructive (NDE) measurements employing electromagnetic induction and digital optical imaging analysis is currently under investigation and preliminary data indicate the potential for meeting the demands of this application. To calibrate high-speed NDE methods, surrogate fuel particle samples are being coated with layers containing a wide array of defect types found to degrade fuel performance and these are being characterized via high-resolution CT and digital radiographic images.

  6. MST Filterability Tests

    SciTech Connect

    Poirier, M. R.; Burket, P. R.; Duignan, M. R.

    2015-03-12

    The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). The low filter flux through the ARP has limited the rate at which radioactive liquid waste can be treated. Recent filter flux has averaged approximately 5 gallons per minute (gpm). Salt Batch 6 has had a lower processing rate and required frequent filter cleaning. Savannah River Remediation (SRR) has a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. In addition, at the time the testing started, SRR was assessing the impact of replacing the 0.1 micron filter with a 0.5 micron filter. This report describes testing of MST filterability to investigate the impact of filter pore size and MST particle size on filter flux and testing of filter enhancers to attempt to increase filter flux. The authors constructed a laboratory-scale crossflow filter apparatus with two crossflow filters operating in parallel. One filter was a 0.1 micron Mott sintered SS filter and the other was a 0.5 micron Mott sintered SS filter. The authors also constructed a dead-end filtration apparatus to conduct screening tests with potential filter aids and body feeds, referred to as filter enhancers. The original baseline for ARP was 5.6 M sodium salt solution with a free hydroxide concentration of approximately 1.7 M.3 ARP has been operating with a sodium concentration of approximately 6.4 M and a free hydroxide concentration of approximately 2.5 M. SRNL conducted tests varying the concentration of sodium and free hydroxide to determine whether those changes had a significant effect on filter flux. The feed slurries for the MST filterability tests were composed of simple salts (NaOH, NaNO2, and NaNO3) and MST (0.2 – 4.8 g/L). The feed slurry for the filter enhancer tests contained simulated salt batch 6 supernate, MST, and filter enhancers.

  7. Nanofiber Filters Eliminate Contaminants

    NASA Technical Reports Server (NTRS)

    2009-01-01

    With support from Phase I and II SBIR funding from Johnson Space Center, Argonide Corporation of Sanford, Florida tested and developed its proprietary nanofiber water filter media. Capable of removing more than 99.99 percent of dangerous particles like bacteria, viruses, and parasites, the media was incorporated into the company's commercial NanoCeram water filter, an inductee into the Space Foundation's Space Technology Hall of Fame. In addition to its drinking water filters, Argonide now produces large-scale nanofiber filters used as part of the reverse osmosis process for industrial water purification.

  8. NATO Advanced Research Workshop: Optics of Biological Particles. Held in Novosibirsk, Russia on 3-6 Oct 2005

    DTIC Science & Technology

    2005-01-01

    A 3. DATES COVERED - 4 . TITLE AND SUBTITLE NATO Advanced Research Workshop Optics of Biological Particles 5a. CONTRACT NUMBER 5b. GRANT...Characterization of Biologi- cal Species” 4 17:20 – 19:00 visit IChK&C 19:00 dinner 2nd day: Tuesday October 4 , 2005 09:00 – 09:30 Virginia Foot...surfaces; (3) erythrocyte lysis in isotonic solution of ammonium chloride; ( 4 ) endocytosis. OPTICS OF RED BLOOD CELLS AND CELL AGGREGATES Alexander V

  9. ADVANCED METHODS FOR THE COMPUTATION OF PARTICLE BEAM TRANSPORT AND THE COMPUTATION OF ELECTROMAGNETIC FIELDS AND MULTIPARTICLE PHENOMENA

    SciTech Connect

    Alex J. Dragt

    2012-08-31

    Since 1980, under the grant DEFG02-96ER40949, the Department of Energy has supported the educational and research work of the University of Maryland Dynamical Systems and Accelerator Theory (DSAT) Group. The primary focus of this educational/research group has been on the computation and analysis of charged-particle beam transport using Lie algebraic methods, and on advanced methods for the computation of electromagnetic fields and multiparticle phenomena. This Final Report summarizes the accomplishments of the DSAT Group from its inception in 1980 through its end in 2011.

  10. Modeling Combined Chemotherapy and Particle Therapy for Locally Advanced Pancreatic Cancer

    PubMed Central

    Durante, Marco; Tommasino, Francesco; Yamada, Shigeru

    2015-01-01

    Pancreatic ductal adenocarcinoma is the only cancer for which deaths are predicted to increase in 2014 and beyond. Combined radiochemotherapy protocols using gemcitabine and hypofractionated X-rays are ongoing in several clinical trials. Recent results indicate that charged particle therapy substantially increases local control of resectable and unresectable pancreas cancer, as predicted from previous radiobiology studies considering the high tumor hypoxia. Combination with chemotherapy improves the overall survival (OS). We compared published data on X-ray and charged particle clinical results with or without adjuvant chemotherapy calculating the biological effective dose. We show that chemoradiotherapy with protons or carbon ions results in 1 year OS significantly higher than those obtained with other treatment schedules. Further hypofractionation using charged particles may result in improved local control and survival. A comparative clinical trial using the standard X-ray scheme vs. the best current standard with carbon ions is crucial and may open new opportunities for this deadly disease. PMID:26217585

  11. Characterizing the distribution of particles in urban stormwater: advancements through improved sampling technology

    USGS Publications Warehouse

    Selbig, William R.

    2014-01-01

    A new sample collection system was developed to improve the representation of sediment in stormwater by integrating the entire water column. The depth-integrated sampler arm (DISA) was able to mitigate sediment stratification bias in storm water, thereby improving the characterization of particle size distribution from urban source areas. Collector streets had the lowest median particle diameter of 8 μm, followed by parking lots, arterial streets, feeder streets, and residential and mixed land use (32, 43, 50, 80 and 95 μm, respectively). Results from this study suggest there is no single distribution of particles that can be applied uniformly to runoff in urban environments; however, integrating more of the entire water column during the sample collection can address some of the shortcomings of a fixed-point sampler by reducing variability and bias caused by the stratification of solids in a water column.

  12. Particle-vibration coupling: Recent advances in microscopic calculations with the Skyrme Hamiltonian

    NASA Astrophysics Data System (ADS)

    Colò, G.; Baldo, M.; Bortignon, P. F.; Rizzo, D.; Bocchi, G.

    2016-11-01

    In this contribution, we report some recent progress in our understanding of particle-vibration coupling (PVC) in nuclei. In particular, we first review the formal development that has allowed some of us to deduce the PVC equations within the Green's functionmethod. Applications are then discussed, both in the case of single-particle states and giant resonances in magic nuclei. We also present a new model that extends the PVC ansatz and is meant to account for the complete low-lying spectra of odd nuclei.

  13. Eddy Current, Magnetic Particle and Hardness Testing, Aviation Quality Control (Advanced): 9227.04.

    ERIC Educational Resources Information Center

    Dade County Public Schools, Miami, FL.

    This unit of instruction includes the principles of eddy current, magnetic particle and hardness testing; standards used for analyzing test results; techniques of operating equipment; interpretation of indications; advantages and limitations of these methods of testing; care and calibration of equipment; and safety and work precautions. Motion…

  14. Advanced 3D electromagnetic and particle-in-cell modeling on structured/unstructured hybrid grids

    SciTech Connect

    Seidel, D.B.; Pasik, M.F.; Kiefer, M.L.; Riley, D.J.; Turner, C.D.

    1998-01-01

    New techniques have been recently developed that allow unstructured, free meshes to be embedded into standard 3-dimensional, rectilinear, finite-difference time-domain grids. The resulting hybrid-grid modeling capability allows the higher resolution and fidelity of modeling afforded by free meshes to be combined with the simplicity and efficiency of rectilinear techniques. Integration of these new methods into the full-featured, general-purpose QUICKSILVER electromagnetic, Particle-In-Cell (PIC) code provides new modeling capability for a wide variety of electromagnetic and plasma physics problems. To completely exploit the integration of this technology into QUICKSILVER for applications requiring the self-consistent treatment of charged particles, this project has extended existing PIC methods for operation on these hybrid unstructured/rectilinear meshes. Several technical issues had to be addressed in order to accomplish this goal, including the location of particles on the unstructured mesh, adequate conservation of charge, and the proper handling of particles in the transition region between structured and unstructured portions of the hybrid grid.

  15. Combination of ozonation, activated carbon, and biological aerated filter for advanced treatment of dyeing wastewater for reuse.

    PubMed

    Zou, Xiao-Ling

    2015-06-01

    Laboratorial scale experiments were performed to investigate and evaluate the performance and removal characteristics of organics, color, and genotoxicity by an integrated process including ozonation, activated carbon (AC), and biological aerated filter (BAF) for recycling biotreated dyeing wastewater (BTDW) collected from a cotton textile factory. Influent chemical oxygen demand (COD) in the range of 156 - 252 mg/L, 5-day biochemical oxygen demand (BOD5) of 13.5 - 21.7 mg/L, and color of 58 - 76° were observed during the 20-day continuous operation. Outflows with average COD of 43 mg/L, BOD5 of 6.6 mg/L, and color of 5.6° were obtained after being decontaminated by the hybrid system with ozone dosage of 0.25 mg O3applied/mg COD0, 40 min ozonation contact time, 30 min hydraulic retention time (HRT) for AC treatment, and 2.5 h HRT for BAF treatment. More than 82 % of the genotoxicity of BTDW was eliminated in the ozonation unit. The genotoxicity of the BAF effluent was less than 1.33 μg 4-nitroquinoline-N-oxide/L. Ozonation could change the organics molecular structures, destroy chromophores, increase the biodegradability, and obviously reduce the genotoxicity of BTDW. Results showed that the combined process could guarantee water reuse with high quality.

  16. Advanced optical correlation and digital methods for pattern matching—50th anniversary of Vander Lugt matched filter

    NASA Astrophysics Data System (ADS)

    Millán, María S.

    2012-10-01

    On the verge of the 50th anniversary of Vander Lugt’s formulation for pattern matching based on matched filtering and optical correlation, we acknowledge the very intense research activity developed in the field of correlation-based pattern recognition during this period of time. The paper reviews some domains that appeared as emerging fields in the last years of the 20th century and have been developed later on in the 21st century. Such is the case of three-dimensional (3D) object recognition, biometric pattern matching, optical security and hybrid optical-digital processors. 3D object recognition is a challenging case of multidimensional image recognition because of its implications in the recognition of real-world objects independent of their perspective. Biometric recognition is essentially pattern recognition for which the personal identification is based on the authentication of a specific physiological characteristic possessed by the subject (e.g. fingerprint, face, iris, retina, and multifactor combinations). Biometric recognition often appears combined with encryption-decryption processes to secure information. The optical implementations of correlation-based pattern recognition processes still rely on the 4f-correlator, the joint transform correlator, or some of their variants. But the many applications developed in the field have been pushing the systems for a continuous improvement of their architectures and algorithms, thus leading towards merged optical-digital solutions.

  17. Initial operation of the Tidd PFBC hot gas clean up filter

    SciTech Connect

    Mudd, M.J.; Hoffman, J.D.

    1993-09-01

    The objective of this program is to evaluate the design and obtain operating experience for up to two Advanced Particle Filter (APF) systems through long-term testing on a slipstream at Ohio Power Company`s Tidd PFBC Demonstration Plant. Performance and reliability of commercial-scale filter modules will be monitored to aid in an assessment of the readiness and economic viability of this technology for commercial PFBC applications.

  18. Realisation and advanced engineering of true optical rugate filters based on nanoporous anodic alumina by sinusoidal pulse anodisation

    NASA Astrophysics Data System (ADS)

    Santos, Abel; Yoo, Jeong Ha; Rohatgi, Charu Vashisth; Kumeria, Tushar; Wang, Ye; Losic, Dusan

    2016-01-01

    This study is the first realisation of true optical rugate filters (RFs) based on nanoporous anodic alumina (NAA) by sinusoidal waves. An innovative and rationally designed sinusoidal pulse anodisation (SPA) approach in galvanostatic mode is used with the aim of engineering the effective medium of NAA in a sinusoidal fashion. A precise control over the different anodisation parameters (i.e. anodisation period, anodisation amplitude, anodisation offset, number of pulses, anodisation temperature and pore widening time) makes it possible to engineer the characteristic reflection peaks and interferometric colours of NAA-RFs, which can be finely tuned across the UV-visible-NIR spectrum. The effect of the aforementioned anodisation parameters on the photonic properties of NAA-RFs (i.e. characteristic reflection peaks and interferometric colours) is systematically assessed in order to establish for the first time a comprehensive rationale towards NAA-RFs with fully controllable photonic properties. The experimental results are correlated with a theoretical model (Looyenga-Landau-Lifshitz - LLL), demonstrating that the effective medium of these photonic nanostructures can be precisely described by the effective medium approximation. NAA-RFs are also demonstrated as chemically selective photonic platforms combined with reflectometric interference spectroscopy (RIfS). The resulting optical sensing system is used to assess the reversible binding affinity between a model drug (i.e. indomethacin) and human serum albumin (HSA) in real-time. Our results demonstrate that this system can be used to determine the overall pharmacokinetic profile of drugs, which is a critical aspect to be considered for the implementation of efficient medical therapies.This study is the first realisation of true optical rugate filters (RFs) based on nanoporous anodic alumina (NAA) by sinusoidal waves. An innovative and rationally designed sinusoidal pulse anodisation (SPA) approach in galvanostatic

  19. Advanced new relaxation filter-selective signal excitation methods for (13)C solid-state nuclear magnetic resonance.

    PubMed

    Asada, Mamiko; Nemoto, Takayuki; Mimura, Hisashi; Sako, Kazuhiro

    2014-10-21

    We have developed new relaxation filter-selective signal excitation (RFS) methods for (13)C solid-state NMR, which enable extraction of the spectrum of a target component from a mixture of several components. These methods are based on the equalization of proton relaxation time in a single domain via rapid intraproton spin diffusion and the difference in proton relaxation time of individual components in the mixture. We recently reported two types of RFS methods using proton spin-lattice relaxation time in the rotating frame ((1)H T1rho) in (13)C solid-state nuclear magnetic resonance (NMR) spectroscopy. Here, to increase the availability of RFS methods, we focus on proton spin-lattice relaxation time ((1)H T1). Introduction of simple pulse sequences to one-dimensional experiments reduced data acquisition time and increased flexibility, and led to the development of two new types of RFS methods using (1)H T1. We then demonstrated these methods by selectively exciting the (13)C signals of target components in a commercially available drug and a number of physical mixtures, and we showed them to be applicable to the quantitative analysis of individual components in these solid mixtures with an experimental duration of 1.5 to about 10 h. The practicality and versatility of these four RFS methods were increased by combining two or more of them, or by using a flip-back pulse, which is an effective means of shortening experimental duration. These RFS methods are suitable for use in a broad range of fields.

  20. ADVANCING THE ION BEAM THIN FILM PLANARIZATION PROCESS FOR THE SMOOTHING OF SUBSTRATE PARTICLES

    SciTech Connect

    Mirkarimi, P B; Spiller, E; Baker, S L; Robinson, J C; Stearns, D G; Liddle, J A; Salmassi, F; Liang, T; Stivers, A R

    2004-10-19

    For a number of technologies small substrate contaminants are undesirable, and for one technology in particular, extreme ultraviolet lithography (EUVL), they can be a very serious issue. We have demonstrated that the Ion Beam Thin Film Planarization Process, a coating process designed to planarize substrate asperities, can be extended to smooth {approx}70 nm and {approx}80 nm diameter particles on EUVL reticle substrates to a height of {approx}0.5 nm, which will render them noncritical in an EUVL printing process. We demonstrate this smoothing process using controlled nanoscale substrate particles and lines fabricated with an e-beam lithography process. The above smoothing process was also modified to yield an excellent reflectance/wavelength uniformity and a good EUV reflectivity for the multilayer, which is required for EUVL reticles. Cross-sectional TEM on a smoothed substrate line defect shows excellent agreement with results obtained from our multilayer growth model.

  1. Current Advances in Virus-Like Particles as a Vaccination Approach against HIV Infection

    PubMed Central

    Zhao, Chongbo; Ao, Zhujun; Yao, Xiaojian

    2016-01-01

    HIV-1 virus-like particles (VLPs) are promising vaccine candidates against HIV-1 infection. They are capable of preserving the native conformation of HIV-1 antigens and priming CD4+ and CD8+ T cell responses efficiently via cross presentation by both major histocompatibility complex (MHC) class I and II molecules. Progress has been achieved in the preclinical research of HIV-1 VLPs as prophylactic vaccines that induce broadly neutralizing antibodies and potent T cell responses. Moreover, the progress in HIV-1 dendritic cells (DC)-based immunotherapy provides us with a new vision for HIV-1 vaccine development. In this review, we describe updates from the past 5 years on the development of HIV-1 VLPs as a vaccine candidate and on the combined use of HIV particles with HIV-1 DC-based immunotherapy as efficient prophylactic and therapeutic vaccination strategies. PMID:26805898

  2. Advanced methods in global gyrokinetic full f particle simulation of tokamak transport

    SciTech Connect

    Ogando, F.; Heikkinen, J. A.; Henriksson, S.; Janhunen, S. J.; Kiviniemi, T. P.; Leerink, S.

    2006-11-30

    A new full f nonlinear gyrokinetic simulation code, named ELMFIRE, has been developed for simulating transport phenomena in tokamak plasmas. The code is based on a gyrokinetic particle-in-cell algorithm, which can consider electrons and ions jointly or separately, as well as arbitrary impurities. The implicit treatment of the ion polarization drift and the use of full f methods allow for simulations of strongly perturbed plasmas including wide orbit effects, steep gradients and rapid dynamic changes. This article presents in more detail the algorithms incorporated into ELMFIRE, as well as benchmarking comparisons to both neoclassical theory and other codes.Code ELMFIRE calculates plasma dynamics by following the evolution of a number of sample particles. Because of using an stochastic algorithm its results are influenced by statistical noise. The effect of noise on relevant magnitudes is analyzed.Turbulence spectra of FT-2 plasma has been calculated with ELMFIRE, obtaining results consistent with experimental data.

  3. The Frontier of Modern Calorimetry: Hardware Advances and Application in Particle Physics Analysis

    NASA Astrophysics Data System (ADS)

    Medvedeva, Tatiana

    While the last missing components of the SM puzzle seem to be successfully found, particle physicists remain hungry for what might be there, beyond the cosy boundaries of the well studies elementary particle world. However, the sophisticated technique of data analysis and acute Monte Carlo simulations remain fruitless. It appears that the successful intrusion into the realm, in which we were not welcome so far, may require a very different implication of effort. All those results might suggest, though banal, that we need an improvement on the hardware side. Indeed, the hadronic calorimeter of CMS is no competitor to its other state-of-art components. This obstacle in many cases significantly complicates the flow of the physics analysis. Besides, the era of high luminosity LHC operation in the offing is calling for the same. After exploration of the analysis debri with 8TeV collision data, we investigate various approaches for better calorimetry for the CMS detector.

  4. Advances and patents about grinding equipments with nano-particle jet minimum quantity lubrication.

    PubMed

    Jia, Dongzhou; Li, Changhe; Wang, Sheng; Zhang, Qiang; Hou, Yali

    2014-01-01

    In recent years, a large number of patents have been devoted to developing minimum quantity lubrication (MQL) grinding techniques that can significantly improve both environmentally conscious and energy saving and costeffective sustainable grinding fluid alternatives. Among them, one patent is about a controllable nano-fluids jet MQL grinding system based on electrostatic atomization. Using the principle of electrostatics, it can achieve the control of droplet transfer by charging the sprayed droplets. This system can improve the uniformity of the droplet spectrum, liquid deposition efficiency and effective utilization of liquid. It can also effectively control the movement patterns of the droplets, thereby reducing the pollution of the environment and providing better health protection for workers. Although researchers accomplished profound and systematic studies on MQL, especially on nano-particles jet MQL. It can solve the shortage of MQL in cooling performance, greatly improve the working environment, save energy and reduce costs to achieve a low-carbon manufacturing. The unique lubricating performance and tribological property of solid nano-particles form nano-particle shearing films at the grinding wheel/workpiece interface, which can enhance the lubricating performance of MQL grinding. Existing studies on MQL grinding equipments, however, cannot meet the needs of the technological development. Therefore, our research provided a general introduction of the latest patients and research progress of nanoparticles jet MQL grinding equipments presented by the research team from Qingdao Technological University.

  5. Remediating radium contaminated legacy sites: Advances made through machine learning in routine monitoring of "hot" particles.

    PubMed

    Varley, Adam; Tyler, Andrew; Smith, Leslie; Dale, Paul; Davies, Mike

    2015-07-15

    The extensive use of radium during the 20th century for industrial, military and pharmaceutical purposes has led to a large number of contaminated legacy sites across Europe and North America. Sites that pose a high risk to the general public can present expensive and long-term remediation projects. Often the most pragmatic remediation approach is through routine monitoring operating gamma-ray detectors to identify, in real-time, the signal from the most hazardous heterogeneous contamination (hot particles); thus facilitating their removal and safe disposal. However, current detection systems do not fully utilise all spectral information resulting in low detection rates and ultimately an increased risk to the human health. The aim of this study was to establish an optimised detector-algorithm combination. To achieve this, field data was collected using two handheld detectors (sodium iodide and lanthanum bromide) and a number of Monte Carlo simulated hot particles were randomly injected into the field data. This allowed for the detection rate of conventional deterministic (gross counts) and machine learning (neural networks and support vector machines) algorithms to be assessed. The results demonstrated that a Neural Network operated on a sodium iodide detector provided the best detection capability. Compared to deterministic approaches, this optimised detection system could detect a hot particle on average 10cm deeper into the soil column or with half of the activity at the same depth. It was also found that noise presented by internal contamination restricted lanthanum bromide for this application.

  6. Advances in Thermal Spray Deposition of Billets for Particle Reinforced Light Metals

    NASA Astrophysics Data System (ADS)

    Wenzelburger, Martin; Zimmermann, Christian; Gadow, Rainer

    2007-04-01

    Forming of light-metals in semi-solid state offers some advantages like low process temperatures, improved mould durability, good flow behavior and fine, globular microstructure of the final material. By the introduction of ceramic particles, increased elastic modulus and yield strength as well as wear resistance and creep behavior can be obtained. By semi-solid forging or semi-solid casting, particle reinforced metals (PRM) can be produced with improved matrix microstructure and beneficial forming process parameters compared to conventional MMC manufacturing techniques. The production of this kind of light metal matrix composites requires the supply of dense semi-finished parts with well defined volume fractions of homogeneously distributed particulate reinforcement. A manufacturing method for cylindrical light metal billets is described that applies thermal spraying as a build-up process for simultaneous deposition of matrix and reinforcement phase with cored wires as spraying material. Thermal spraying leads to small grain sizes and prevents dendrite formation. However, long process cycle times lead to billet heating and recrystallization of the matrix microstructure. In order to preserve small grain sizes that enable semi-solid forming, the thermal spraying process was analyzed by in-flight particle analysis and thermography. As a consequence, the deposition process was optimized by adaptation of the thermal spraying parameters and by application of additional cooling, leading to lower billet temperatures and finer PRM billet microstructure.

  7. Advances in Thermal Spray Deposition of Billets for Particle Reinforced Light Metals

    SciTech Connect

    Wenzelburger, Martin; Zimmermann, Christian; Gadow, Rainer

    2007-04-07

    Forming of light-metals in semi-solid state offers some advantages like low process temperatures, improved mould durability, good flow behavior and fine, globular microstructure of the final material. By the introduction of ceramic particles, increased elastic modulus and yield strength as well as wear resistance and creep behavior can be obtained. By semi-solid forging or semi-solid casting, particle reinforced metals (PRM) can be produced with improved matrix microstructure and beneficial forming process parameters compared to conventional MMC manufacturing techniques. The production of this kind of light metal matrix composites requires the supply of dense semi-finished parts with well defined volume fractions of homogeneously distributed particulate reinforcement. A manufacturing method for cylindrical light metal billets is described that applies thermal spraying as a build-up process for simultaneous deposition of matrix and reinforcement phase with cored wires as spraying material. Thermal spraying leads to small grain sizes and prevents dendrite formation. However, long process cycle times lead to billet heating and recrystallization of the matrix microstructure. In order to preserve small grain sizes that enable semi-solid forming, the thermal spraying process was analyzed by in-flight particle analysis and thermography. As a consequence, the deposition process was optimized by adaptation of the thermal spraying parameters and by application of additional cooling, leading to lower billet temperatures and finer PRM billet microstructure.

  8. Characterization of exposures to nanoscale particles and fibers during solid core drilling of hybrid carbon nanotube advanced composites.

    PubMed

    Bello, Dhimiter; Wardle, Brian L; Zhang, Jie; Yamamoto, Namiko; Santeufemio, Christopher; Hallock, Marilyn; Virji, M Abbas

    2010-01-01

    This work investigated exposures to nanoparticles and nanofibers during solid core drilling of two types of advanced carbon nanotube (CNT)-hybrid composites: (1) reinforced plastic hybrid laminates (alumina fibers and CNT); and (2) graphite-epoxy composites (carbon fibers and CNT). Multiple real-time instruments were used to characterize the size distribution (5.6 nm to 20 microm), number and mass concentration, particle-bound polyaromatic hydrocarbons (b-PAHs), and surface area of airborne particles at the source and breathing zone. Time-integrated samples included grids for electron microscopy characterization of particle morphology and size resolved (2 nm to 20 microm) samples for the quantification of metals. Several new important findings herein include generation of airborne clusters of CNTs not seen during saw-cutting of similar composites, fewer nanofibers and respirable fibers released, similarly high exposures to nanoparticles with less dependence on the composite thickness, and ultrafine (< 5 nm) aerosol originating from thermal degradation of the composite material.

  9. Removal of total and antibiotic resistant bacteria in advanced wastewater treatment by ozonation in combination with different filtering techniques.

    PubMed

    Lüddeke, Frauke; Heß, Stefanie; Gallert, Claudia; Winter, Josef; Güde, Hans; Löffler, Herbert

    2015-02-01

    Elimination of bacteria by ozonation in combination with charcoal or slow sand filtration for advanced sewage treatment to improve the quality of treated sewage and to reduce the potential risk for human health of receiving surface waters was investigated in pilot scale at the sewage treatment plant Eriskirch, Baden-Wuerttemberg/Germany. To determine the elimination of sewage bacteria, inflowing and leaving wastewater of different treatment processes was analysed in a culture-based approach for its content of Escherichia coli, enterococci and staphylococci and their resistance against selected antibiotics over a period of 17 month. For enterococci, single species and their antibiotic resistances were identified. In comparison to the established flocculation filtration at Eriskirch, ozonation plus charcoal or sand filtration (pilot-scale) reduced the concentrations of total and antibiotic resistant E. coli, enterococci and staphylococci. However, antibiotic resistant E. coli and staphylococci apparently survived ozone treatment better than antibiotic sensitive strains. Neither vancomycin resistant enterococci nor methicillin resistant Staphylococcus aureus (MRSA) were detected. The decreased percentage of antibiotic resistant enterococci after ozonation may be explained by a different ozone sensitivity of species: Enterococcus faecium and Enterococcus faecalis, which determined the resistance-level, seemed to be more sensitive for ozone than other Enterococcus-species. Overall, ozonation followed by charcoal or sand filtration led to 0.8-1.1 log-units less total and antibiotic resistant E. coli, enterococci and staphylococci, as compared to the respective concentrations in treated sewage by only flocculation filtration. Thus, advanced wastewater treatment by ozonation plus charcoal or sand filtration after common sewage treatment is an effective tool for further elimination of microorganisms from sewage before discharge in surface waters.

  10. Vapor purification with self-cleaning filter

    SciTech Connect

    Josephson, Gary B.; Heath, William O.; Aardahl, Christopher L.

    2003-12-09

    A vapor filtration device including a first electrode, a second electrode, and a filter between the first and second electrodes is disclosed. The filter is formed of dielectric material and the device is operated by applying a first electric potential between the electrodes to polarize the dielectric material such that upon passing a vapor stream through the filter, particles from the vapor stream are deposited onto the filter. After depositing the particles a second higher voltage is applied between the electrodes to form a nonthermal plasma around the filter to vaporize the collected particles thereby cleaning the filter. The filter can be a packed bed or serpentine filter mat, and an optional upstream corona wire can be utilized to charge airborne particles prior to their deposition on the filter.

  11. Advances in the field of single-particle cryo-electron microscopy over the last decade.

    PubMed

    Frank, Joachim

    2017-02-01

    In single-particle cryo-electron microscopy (cryo-EM), molecules suspended in a thin aqueous layer are rapidly frozen and imaged at cryogenic temperature in the transmission electron microscope. From the random projection views, a three-dimensional image is reconstructed, enabling the structure of the molecule to be obtained. In this article I discuss technological progress over the past decade, which has, in my own field of study, culminated in the determination of ribosome structure at 2.5-Å resolution. I also discuss likely future improvements in methodology.

  12. Westinghouse hot gas filter system development

    SciTech Connect

    Lippert, T.E.; Bruck, G.J.; Sanjana, Z.N.; Alvin, M.A.; Newby, R.A.

    1998-12-31

    Integrated Gasification Combined Cycles (IGCC) and Pressurized Fluidized Bed Combustion (PFBC) are being developed and demonstrated for commercial, power generation application. Hot gas particulate filters are key components for the successful implementation of IGCC and PFBC in power generation gas turbine cycles. The objective of this work is to develop and qualify through analysis and testing a practical hot gas ceramic barrier filter system that meets the performance and operational requirements for these applications. This paper reports on the development and status of testing of the Westinghouse Advanced Hot Gas Particle Filter (W-APF) including: 4,246 hours of testing that has now been completed at the Foster Wheeler 10 MW PCFB facility located in Karhula, Finland; operation of the W-APF in conjunction with the Foster Wheeler Advanced HIPPS Test Program being conducted at their Livingston, New Jersey site; approximately 2,100 hours of operation of the W-APF at the SCS/PSDF site on the MWK transport reactor test loop; the design, installation and startup status of the W-APF unit supplied to the 95 MW Pinon Pine IGCC Clean Coal Demonstration, Reno, Nevada; and the status of the Westinghouse development and testing of HGF`s for Biomass Power Generation. Results reported include operating history, operating characteristics and filter performance. Schedules and objectives for future testing are summarized. The status of the 200 MWe PCFB Clean Coal Demonstration Project, City of Lakeland Florida and 75 MW(e) Minnesota Agriculture Biomass Power Project are summarized.

  13. Advanced oxidation of natural organic matter using hydrogen peroxide and iron-coated pumice particles.

    PubMed

    Kitis, M; Kaplan, S S

    2007-08-01

    The oxidative removal of natural organic matter (NOM) from waters using hydrogen peroxide and iron-coated pumice particles as heterogeneous catalysts was investigated. Two NOM sources were tested: humic acid solution and a natural source water. Iron coated pumice removed about half of the dissolved organic carbon (DOC) concentration at a dose of 3000 mg l(-1) in 24 h by adsorption only. Original pumice and peroxide dosed together provided UV absorbance reductions as high as 49%, mainly due to the presence of metal oxides including Al(2)O(3), Fe(2)O(3) and TiO(2) in the natural pumice, which are known to catalyze the decomposition of peroxide forming strong oxidants. Coating the original pumice particles with iron oxides significantly enhanced the removal of NOM with peroxide. A strong linear correlation was found between iron contents of coated pumices and UV absorbance reductions. Peroxide consumption also correlated with UV absorbance reduction. Control experiments proved the effective coating and the stability of iron oxide species bound on pumice surfaces. Results overall indicated that in addition to adsorptive removal of NOM by metal oxides on pumice surfaces, surface reactions between iron oxides and peroxide result in the formation of strong oxidants, probably like hydroxyl radicals, which further oxidize both adsorbed NOM and remaining NOM in solution, similar to those in Fenton-like reactions.

  14. Advances in nuclear data and all-particle transport for radiation oncology

    SciTech Connect

    White, R.M.; Chadwick, M.B.; Chandler, W.P.; Hartmann Siantar, C.L.; Westbrook, C.K.

    1994-05-01

    Fast neutrons have been used to treat over 15,000 cancer patients worldwide and proton therapy is rapidly emerging as a treatment of choice for tumors around critical anatomical structures. Neutron therapy requires evaluated data to {approximately}70 MeV while proton therapy requires data to {approximately}250 MeV. Collaboration between Lawrence Livermore National Laboratory (LLNL) and the medical physics community has revealed limitations in nuclear cross section evaluations and radiation transport capabilities that have prevented neutron and proton radiation therapy centers from using Monte Carlo calculations to accurately predict dose in patients. These evaluations require energy- and angle-dependent cross sections for secondary neutrons, charged-particles and recoil nuclei. We are expanding the LLNL nuclear databases to higher energies for biologically important elements and have developed a three-dimensional, all-particle Monte Carlo radiation transport code that uses computer-assisted-tomography (CT) images as the input mesh. This code, called PEREGRINE calculates dose distributions in the human body and can be used as a tool to determine the dependence of dose on details of the evaluated nuclear data. In this paper, we will review the status of the nuclear data required for neutron and proton therapy, describe the capabilities of the PEREGRINE package, and show the effects of tissue inhomogeneities on dose distribution.

  15. The Search for Fractional Charge Particles in an Advanced, Automated Variation of the Millikan Experiment

    NASA Astrophysics Data System (ADS)

    Lee, I. T.; Halyo, V.; Lee, E. R.; Loomba, D.; Perl, M. L.

    2001-04-01

    We will present a variation on the Millikan apparatus designed to look for fractionally charged particles in bulk materials, and results from the current run. Oil drops are produced from a drop-on-demand ejector, and imaged by a digital CCD camera and framegrabber combination. A networked Linux cluster is used to simultaneously collect and analyze data, and to monitor and control the apparatus. The experiment is fully automated, and utilizes laminar air flow to make possible the accurate measurements of charge on large (20 micron) fluid drops. The experiment has the capability to process a total of 10^7 to 10^8 drops (20-200 mg), and the ability to use large drops enables the search to be carried out in mineral suspensions.

  16. Sintered composite filter

    DOEpatents

    Bergman, W.

    1986-05-02

    A particulate filter medium formed of a sintered composite of 0.5 micron diameter quartz fibers and 2 micron diameter stainless steel fibers is described. Preferred composition is about 40 vol.% quartz and about 60 vol.% stainless steel fibers. The media is sintered at about 1100/sup 0/C to bond the stainless steel fibers into a cage network which holds the quartz fibers. High filter efficiency and low flow resistance are provided by the smaller quartz fibers. High strength is provided by the stainless steel fibers. The resulting media has a high efficiency and low pressure drop similar to the standard HEPA media, with tensile strength at least four times greater, and a maximum operating temperature of about 550/sup 0/C. The invention also includes methods to form the composite media and a HEPA filter utilizing the composite media. The filter media can be used to filter particles in both liquids and gases.

  17. Disk filter

    DOEpatents

    Bergman, Werner

    1986-01-01

    An electric disk filter provides a high efficiency at high temperature. A hollow outer filter of fibrous stainless steel forms the ground electrode. A refractory filter material is placed between the outer electrode and the inner electrically isolated high voltage electrode. Air flows through the outer filter surfaces through the electrified refractory filter media and between the high voltage electrodes and is removed from a space in the high voltage electrode.

  18. Disk filter

    DOEpatents

    Bergman, W.

    1985-01-09

    An electric disk filter provides a high efficiency at high temperature. A hollow outer filter of fibrous stainless steel forms the ground electrode. A refractory filter material is placed between the outer electrode and the inner electrically isolated high voltage electrode. Air flows through the outer filter surfaces through the electrified refractory filter media and between the high voltage electrodes and is removed from a space in the high voltage electrode.

  19. Inversely estimating the vertical profile of the soil CO2 production rate in a deciduous broadleaf forest using a particle filtering method.

    PubMed

    Sakurai, Gen; Yonemura, Seiichiro; Kishimoto-Mo, Ayaka W; Murayama, Shohei; Ohtsuka, Toshiyuki; Yokozawa, Masayuki

    2015-01-01

    Carbon dioxide (CO2) efflux from the soil surface, which is a major source of CO2 from terrestrial ecosystems, represents the total CO2 production at all soil depths. Although many studies have estimated the vertical profile of the CO2 production rate, one of the difficulties in estimating the vertical profile is measuring diffusion coefficients of CO2 at all soil depths in a nondestructive manner. In this study, we estimated the temporal variation in the vertical profile of the CO2 production rate using a data assimilation method, the particle filtering method, in which the diffusion coefficients of CO2 were simultaneously estimated. The CO2 concentrations at several soil depths and CO2 efflux from the soil surface (only during the snow-free period) were measured at two points in a broadleaf forest in Japan, and the data were assimilated into a simple model including a diffusion equation. We found that there were large variations in the pattern of the vertical profile of the CO2 production rate between experiment sites: the peak CO2 production rate was at soil depths around 10 cm during the snow-free period at one site, but the peak was at the soil surface at the other site. Using this method to estimate the CO2 production rate during snow-cover periods allowed us to estimate CO2 efflux during that period as well. We estimated that the CO2 efflux during the snow-cover period (about half the year) accounted for around 13% of the annual CO2 efflux at this site. Although the method proposed in this study does not ensure the validity of the estimated diffusion coefficients and CO2 production rates, the method enables us to more closely approach the "actual" values by decreasing the variance of the posterior distribution of the values.

  20. Inversely Estimating the Vertical Profile of the Soil CO2 Production Rate in a Deciduous Broadleaf Forest Using a Particle Filtering Method

    PubMed Central

    Sakurai, Gen; Yonemura, Seiichiro; Kishimoto-Mo, Ayaka W.; Murayama, Shohei; Ohtsuka, Toshiyuki; Yokozawa, Masayuki

    2015-01-01

    Carbon dioxide (CO2) efflux from the soil surface, which is a major source of CO2 from terrestrial ecosystems, represents the total CO2 production at all soil depths. Although many studies have estimated the vertical profile of the CO2 production rate, one of the difficulties in estimating the vertical profile is measuring diffusion coefficients of CO2 at all soil depths in a nondestructive manner. In this study, we estimated the temporal variation in the vertical profile of the CO2 production rate using a data assimilation method, the particle filtering method, in which the diffusion coefficients of CO2 were simultaneously estimated. The CO2 concentrations at several soil depths and CO2 efflux from the soil surface (only during the snow-free period) were measured at two points in a broadleaf forest in Japan, and the data were assimilated into a simple model including a diffusion equation. We found that there were large variations in the pattern of the vertical profile of the CO2 production rate between experiment sites: the peak CO2 production rate was at soil depths around 10 cm during the snow-free period at one site, but the peak was at the soil surface at the other site. Using this method to estimate the CO2 production rate during snow-cover periods allowed us to estimate CO2 efflux during that period as well. We estimated that the CO2 efflux during the snow-cover period (about half the year) accounted for around 13% of the annual CO2 efflux at this site. Although the method proposed in this study does not ensure the validity of the estimated diffusion coefficients and CO2 production rates, the method enables us to more closely approach the “actual” values by decreasing the variance of the posterior distribution of the values. PMID:25793387

  1. Advanced treatment of biologically pretreated coal gasification wastewater using a novel anoxic moving bed biofilm reactor (ANMBBR)-biological aerated filter (BAF) system.

    PubMed

    Zhuang, Haifeng; Han, Hongjun; Jia, Shengyong; Zhao, Qian; Hou, Baolin

    2014-04-01

    A novel system integrating anoxic moving bed biofilm reactor (ANMBBR) and biological aerated filter (BAF) with short-cut biological nitrogen removal (SBNR) process was investigated as advanced treatment of real biologically pretreated coal gasification wastewater (CGW). The results showed the system had efficient capacity of degradation of pollutants especially nitrogen removal. The best performance was obtained at hydraulic residence times of 12h and nitrite recycling ratios of 200%. The removal efficiencies of COD, total organic carbon, NH4(+)-N, total phenols and total nitrogen (TN) were 74.6%, 70.0%, 85.0%, 92.7% and 72.3%, the corresponding effluent concentrations were 35.1, 18.0, 4.8, 2.2 and 13.6mg/L, respectively. Compared with traditional A(2)/O process, the system had high performance of NH4(+)-N and TN removal, especially under the high toxic loading. Moreover, ANMBBR played a key role in eliminating toxicity and degrading refractory compounds, which was beneficial to improve biodegradability of raw wastewater for SBNR process.

  2. Mathematical modeling of flow field in ceramic candle filter

    NASA Astrophysics Data System (ADS)

    Seo, Taewon; Kim, Heuy-Dong; Choi, Joo-Hong; Chung, Jae Hwa

    1998-06-01

    Integrated gasification combined cycle (IGCC) is one of the candidates to achieve stringent environmental regulation among the clean coal technologies. Advancing the technology of the hot gas cleanup systems is the most critical component in the development of the IGCC. Thus the aim of this study is to understand the flow field in the ceramic filter and the influence of ceramic filter in removal of the particles contained in the hot gas flow. The numerical model based on the Reynolds stress turbulence model with the Darcy’s law in the porous region is adopted. It is found that the effect of the porosity in the flowfield is negligibly small while the effect of the filter length is significant. It is also found as the permeability decreases, the reattachment point due to the flow separation moves upstream. This is because the fluid is sucked into the filter region due to the pressure drop before the flow separation occurs. The particle follows well with the fluid stream and the particle is directly sucked into the filter due to the pressure drop even in the flow separation region.

  3. Advanced laser particle accelerator development at LANL: from fast ignition to radiation oncology

    SciTech Connect

    Flippo, Kirk A; Gaillard, Sandrine A; Offermann, D T; Cobble, J A; Schmitt, M J; Gautier, D C; Kwan, T J T; Montgomery, D S; Kluge, Thomas; Bussmann, Micheal; Bartal, T; Beg, F N; Gall, B; Geissel, M; Korgan, G; Kovaleski, S; Lockard, T; Malekos, S; Schollmeier, M; Sentoku, Y; Cowan, T E

    2010-01-01

    Laser-plasma accelerated ion and electron beam sources are an emerging field with vast prospects, and promise many superior applications in a variety of fields such as hadron cancer therapy, compact radioisotope generation, table-top nuclear physics, laboratory astrophysics, nuclear forensics, waste transmutation, SN M detection, and inertial fusion energy. LANL is engaged in several projects seeking to develop compact high current and high energy ion and electron sources. We are especially interested in two specific applications: ion fast ignition/capsule perturbation and radiation oncology in conjunction with our partners at the ForschungsZentrum Dresden-Rossendorf (FZD). Laser-to-beam conversion efficiencies of over 10% are needed for practical applications, and we have already shown inherent etliciencies of >5% from flat foils, on Trident using only a 5th of the intensity and energy of the Nova Petawatt. With clever target designs, like structured curved cone targets, we have also been able to achieve major ion energy gains, leading to the highest energy laser-accelerated proton beams in the world. These new target designs promise to help usher in the next generation of particle sources realizing the potential of laser-accelerated beams.

  4. Advanced Laser Particle Accelerator Development at LANL: From Fast Ignition to Radiation Oncology

    SciTech Connect

    Flippo, K. A.; Offermann, D. T.; Cobble, J. A.; Schmitt, M. J.; Gautier, D. C.; Kwan, T. J.; Montgomery, D. S.; Gaillard, S. A.; Kluge, T.; Bussmann, M.; Cowan, T. E.; Bartal, T.; Beg, F. N.; Gall, B.; Kovaleski, S.; Geissel, M.; Schollmeier, M.; Korgan, G.; Malekos, S.; Lockard, T.

    2010-11-04

    Laser-plasma accelerated ion and electron beam sources are an emerging field with vast prospects, and promise many superior applications in a variety of fields such as hadron cancer therapy, compact radioisotope generation, table-top nuclear physics, laboratory astrophysics, nuclear forensics, waste transmutation, Special Nuclear Material (SNM) detection, and inertial fusion energy. LANL is engaged in several projects seeking to develop compact high-current and high-energy ion and electron sources. We are especially interested in two specific applications: ion fast ignition/capsule perturbation and radiation oncology. Laser-to-beam conversion efficiencies of over 10% are needed for practical applications, and we have already shown inherent efficiencies of >5% from flat foils, on Trident using only a 5th of the intensity and energy of the Nova Petawatt laser. With clever target designs, like structured curved cone targets, we have also been able to achieve major ion energy gains, leading to the highest energy laser-accelerated proton beams in the world [3]. These new target designs promise to help usher in the next generation of particle sources realizing the potential of laser-accelerated beams.

  5. Water Filters

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The Aquaspace H2OME Guardian Water Filter, available through Western Water International, Inc., reduces lead in water supplies. The filter is mounted on the faucet and the filter cartridge is placed in the "dead space" between sink and wall. This filter is one of several new filtration devices using the Aquaspace compound filter media, which combines company developed and NASA technology. Aquaspace filters are used in industrial, commercial, residential, and recreational environments as well as by developing nations where water is highly contaminated.

  6. Numerical simulation of large fabric filter

    NASA Astrophysics Data System (ADS)

    Sedláček, Jan; Kovařík, Petr

    2012-04-01

    Fabric filters are used in the wide range of industrial technologies for cleaning of incoming or exhaust gases. To achieve maximal efficiency of the discrete phase separation and long lifetime of the filter hoses, it is necessary to ensure uniform load on filter surface and to avoid impacts of heavy particles with high velocities to the filter hoses. The paper deals with numerical simulation of two phase flow field in a large fabric filter. The filter is composed of six chambers with approx. 1600 filter hoses in total. The model was simplified to one half of the filter, the filter hoses walls were substituted by porous zones. The model settings were based on experimental data, especially on the filter pressure drop. Unsteady simulations with different turbulence models were done. Flow field together with particles trajectories were analyzed. The results were compared with experimental observations.

  7. Fabrication of a Common-mode Noise Filter for Balanced-mode Signal Transmission using Mn-Zn Ferrite Particle/Polyimide Composite Thick Film

    NASA Astrophysics Data System (ADS)

    Sato, Toshiro; Kokai, Takahiro; Moroishi, Masashi; Yamasawa, Kiyohito; Sakuma, Toshiyuki; Karasawa, Hiroki; Hirasawa, Koichi

    To develop a common-mode noise filter for balanced-mode digital signal interfaces such as USB ver. 2 and IEEE 1394, a Mn-Zn ferrite/Polyimide composite thick film was fabricated and applied to the filter device. The polycrystalline Mn-Zn ferrite powder and polyimide precursor liquid solution were used as the starting materials for the composite thick film. The composite film had a large imaginary part of complex permeability at high frequencies over 1GHz, and high permittivity. The common-mode noise filter using the composite film exhibited the common-mode suppression of over 10dB in the frequency range over 1GHz.

  8. Filtered cathodic arc source

    DOEpatents

    Falabella, S.; Sanders, D.M.

    1994-01-18

    A continuous, cathodic arc ion source coupled to a macro-particle filter capable of separation or elimination of macro-particles from the ion flux produced by cathodic arc discharge is described. The ion source employs an axial magnetic field on a cathode (target) having tapered sides to confine the arc, thereby providing high target material utilization. A bent magnetic field is used to guide the metal ions from the target to the part to be coated. The macro-particle filter consists of two straight solenoids, end to end, but placed at 45[degree] to one another, which prevents line-of-sight from the arc spot on the target to the parts to be coated, yet provides a path for ions and electrons to flow, and includes a series of baffles for trapping the macro-particles. 3 figures.

  9. Filtered cathodic arc source

    DOEpatents

    Falabella, Steven; Sanders, David M.

    1994-01-01

    A continuous, cathodic arc ion source coupled to a macro-particle filter capable of separation or elimination of macro-particles from the ion flux produced by cathodic arc discharge. The ion source employs an axial magnetic field on a cathode (target) having tapered sides to confine the arc, thereby providing high target material utilization. A bent magnetic field is used to guide the metal ions from the target to the part to be coated. The macro-particle filter consists of two straight solenoids, end to end, but placed at 45.degree. to one another, which prevents line-of-sight from the arc spot on the target to the parts to be coated, yet provides a path for ions and electrons to flow, and includes a series of baffles for trapping the macro-particles.

  10. Filter Component Assessment

    SciTech Connect

    Alvin, M.A.; Lippert, T.E.; Diaz, E.S.; Smeltzer, E.E.

    1996-12-31

    Advanced particulate filtration systems are currently being developed at Westinghouse for use in both coal-fired Integrated Gasification Combined Cycle (IGCC) and Pressurized Fluidized Bed Combustion (PFBC) systems. To date, Westinghouse has demonstrated 5855 hours of successful operation of first generation monolithic filter elements in PFBC applications when ash bridging or process thermal transient excursions are avoided. Alternate advanced monolithic and second generation fiber reinforced, filament wound and vacuum infiltrated filters are also being developed which are considered to have enhanced high temperature creep resistance, improved fracture toughness, or enhanced thermal shock characteristics, respectively. Mechanical and component fabrication improvements, as well as degradation mechanisms for each filter element have been identified by Westinghouse during exposure to simulated PFBC operating conditions and alkali-containing steam/air environments. Additional effort is currently being focused on determining the stability of the advanced monolithic high temperature creep resistant clay bonded silicon carbide (SiC) materials, alumina/mullite, and chemically vapor infiltrated (CVI) SiC materials during operation in the Westinghouse Advanced Particulate Filtration (W-APF) system at Foster Wheeler`s pressurized circulating fluidized-bed combustion (PCFBC) test facility in Karhula, Finland. Select advanced filter materials are being defined for additional long-term exposure in integrated gasification combined cycle (IGCC) gas streams. The results of these efforts are summarized in this paper. 6 refs., 7 figs., 11 tabs.

  11. Biological Filters.

    ERIC Educational Resources Information Center

    Klemetson, S. L.

    1978-01-01

    Presents the 1978 literature review of wastewater treatment. The review is concerned with biological filters, and it covers: (1) trickling filters; (2) rotating biological contractors; and (3) miscellaneous reactors. A list of 14 references is also presented. (HM)

  12. Metallic Filters

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Filtration technology originated in a mid 1960's NASA study. The results were distributed to the filter industry, an HR Textron responded, using the study as a departure for the development of 421 Filter Media. The HR system is composed of ultrafine steel fibers metallurgically bonded and compressed so that the pore structure is locked in place. The filters are used to filter polyesters, plastics, to remove hydrocarbon streams, etc. Several major companies use the product in chemical applications, pollution control, etc.

  13. Filter validation.

    PubMed

    Madsen, Russell E

    2006-01-01

    Validation of a sterilizing filtration process is critical since it is impossible with currently available technology to measure the sterility of each filled container; therefore, sterility assurance of the filtered product must be achieved through validation of the filtration process. Validating a pharmaceutical sterile filtration process involves three things: determining the effect of the liquid on the filter, determining the effect of the filter on the liquid, and demonstrating that the filter removes all microorganisms from the liquid under actual processing conditions.

  14. Flight prototype regenerative particulate filter system development

    NASA Technical Reports Server (NTRS)

    Green, D. C.; Garber, P. J.

    1974-01-01

    The effort to design, fabricate, and test a flight prototype Filter Regeneration Unit used to regenerate (clean) fluid particulate filter elements is reported. The design of the filter regeneration unit and the results of tests performed in both one-gravity and zero-gravity are discussed. The filter regeneration unit uses a backflush/jet impingement method of regenerating fluid filter elements that is highly efficient. A vortex particle separator and particle trap were designed for zero-gravity use, and the zero-gravity test results are discussed. The filter regeneration unit was designed for both inflight maintenance and ground refurbishment use on space shuttle and future space missions.

  15. FILTER TREATMENT

    DOEpatents

    Sutton, J.B.; Torrey, J.V.P.

    1958-08-26

    A process is described for reconditioning fused alumina filters which have become clogged by the accretion of bismuth phosphate in the filter pores, The method consists in contacting such filters with faming sulfuric acid, and maintaining such contact for a substantial period of time.

  16. Water Filters

    NASA Technical Reports Server (NTRS)

    1987-01-01

    A compact, lightweight electrolytic water filter generates silver ions in concentrations of 50 to 100 parts per billion in the water flow system. Silver ions serve as effective bactericide/deodorizers. Ray Ward requested and received from NASA a technical information package on the Shuttle filter, and used it as basis for his own initial development, a home use filter.

  17. Using advanced dispersion models and mobile monitoring to characterize spatial patterns of ultrafine particles in an urban area

    NASA Astrophysics Data System (ADS)

    Zwack, Leonard M.; Hanna, Steven R.; Spengler, John D.; Levy, Jonathan I.

    2011-09-01

    In urban settings with elevated bridges, buildings, and other complex terrain, the relationship between traffic and air pollution can be highly variable and difficult to accurately characterize. Atmospheric dispersion models are often used in this context, but incorporating background concentrations and characterizing emissions at high spatiotemporal resolution is challenging, especially for ultrafine particles (UFPs). Ambient pollutant monitoring can characterize this relationship, especially when using continuous real-time monitoring. However, it is challenging to quantify local source contributions over background or to characterize spatial patterns across a neighborhood. The goal of this study is to evaluate contributions of traffic to neighborhood-scale air pollution using a combination of regression models derived from mobile UFP monitoring observations collected in Brooklyn, NY and outputs from the Quick Urban & Industrial Complex (QUIC) model. QUIC is a dispersion model that can explicitly take into account the three-dimensional shapes of buildings. The monitoring-based regression model characterized concentration gradients from a major elevated roadway, controlling for real-time traffic volume, meteorological variables, and other local sources. QUIC was applied to simulate dispersion from this same major roadway. The relative concentration decreases with distance from the roadway estimated by the monitoring-based regression model after removal of background and by QUIC were similar. Horizontal contour plots with both models demonstrated non-uniform patterns related to building configuration and source heights. We used the best-fit relationship between the monitoring-based regression model after removal of background and the QUIC outputs ( R2 = 0.80) to estimate a UFP emissions factor of 5.7 × 10 14 particles/vehicle-km, which was relatively consistent across key model assumptions. Our joint applications of novel techniques for analyzing mobile monitoring

  18. A multireader diagnostic performance study of low-contrast detectability on a third-generation dual-source CT scanner: filtered back projection versus advanced modeled iterative reconstruction

    NASA Astrophysics Data System (ADS)

    Solomon, Justin; Mileto, Achille; Ramirez-Giraldo, Juan Carlos; Samei, Ehsan

    2015-03-01

    The purpose of this work was to compare CT low-contrast detectability between two reconstruction algorithms, filtered back-projection (FBP) and advanced modeled iterative reconstruction (ADMIRE). A phantom was designed with a range of low-contrast circular inserts representing 5 contrast levels and 3 sizes. The phantom was imaged on a third-generation dual-source CT scanner (SOMATOM Definition Force, Siemens Healthcare) under various dose levels (0.74 - 5.8 mGy CTDIVol). Images were reconstructed using different settings of slice thickness (0.6 - 5 mm) and reconstruction algorithms (FBP and ADMIRE with strength of 3-5) and were assessed by eleven blinded and independent readers using a two alternative forced choice (2AFC) detection experiment. A second observer experiment was further performed in which observers scored the images based on the total number of visible object groups. Detection performance increased with increasing contrast, size, dose, with accuracy ranging from 50% (i.e., guessing) to 87% with an average inter-observer variability of ±7%. The use of ADMIRE-3 increased performance by 5.2% resulting in an estimated dose reduction potential of 56-60%. The results from the second experiment also showed increased number of visible object groups for increasing dose, slice thickness, and ADMIRE strength. The score difference between FBP and ADMIRE was 0.9, 1.3, and 2.1 for ADMIRE strengths of 3, 4, and 5, respectively, resulting in estimated dose reduction potentials between 4-80%. Overall, the data indicated potential to image at reduced doses while maintaining comparable image quality when using ADMIRE compared to FBP.

  19. Advanced Simultion of Digital Filters.

    DTIC Science & Technology

    1980-09-01

    REPORT DOCUMENTATION PAGE m o m iTwca -- oS ____ ___ ____ __ ____ ___ ____ ___ ____ _ P~lm3 COUPLSITl4 PORN REPORMT U虪 0. G0VtF Acch 1O F R...States Military Academy, 1973 Submitted in partial fulfillment of the k. S requirements for the degree of PIC ,. MASTER OF SCIENCE IN ELECTRICAL

  20. Magnetic particle imaging: advancements and perspectives for real-time in vivo monitoring and image-guided therapy

    NASA Astrophysics Data System (ADS)

    Pablico-Lansigan, Michele H.; Situ, Shu F.; Samia, Anna Cristina S.

    2013-05-01

    Magnetic particle imaging (MPI) is an emerging biomedical imaging technology that allows the direct quantitative mapping of the spatial distribution of superparamagnetic iron oxide nanoparticles. MPI's increased sensitivity and short image acquisition times foster the creation of tomographic images with high temporal and spatial resolution. The contrast and sensitivity of MPI is envisioned to transcend those of other medical imaging modalities presently used, such as magnetic resonance imaging (MRI), X-ray scans, ultrasound, computed tomography (CT), positron emission tomography (PET) and single photon emission computed tomography (SPECT). In this review, we present an overview of the recent advances in the rapidly developing field of MPI. We begin with a basic introduction of the fundamentals of MPI, followed by some highlights over the past decade of the evolution of strategies and approaches used to improve this new imaging technique. We also examine the optimization of iron oxide nanoparticle tracers used for imaging, underscoring the importance of size homogeneity and surface engineering. Finally, we present some future research directions for MPI, emphasizing the novel and exciting opportunities that it offers as an important tool for real-time in vivo monitoring. All these opportunities and capabilities that MPI presents are now seen as potential breakthrough innovations in timely disease diagnosis, implant monitoring, and image-guided therapeutics.

  1. Ceramic fiber reinforced filter

    DOEpatents

    Stinton, David P.; McLaughlin, Jerry C.; Lowden, Richard A.

    1991-01-01

    A filter for removing particulate matter from high temperature flowing fluids, and in particular gases, that is reinforced with ceramic fibers. The filter has a ceramic base fiber material in the form of a fabric, felt, paper of the like, with the refractory fibers thereof coated with a thin layer of a protective and bonding refractory applied by chemical vapor deposition techniques. This coating causes each fiber to be physically joined to adjoining fibers so as to prevent movement of the fibers during use and to increase the strength and toughness of the composite filter. Further, the coating can be selected to minimize any reactions between the constituents of the fluids and the fibers. A description is given of the formation of a composite filter using a felt preform of commercial silicon carbide fibers together with the coating of these fibers with pure silicon carbide. Filter efficiency approaching 100% has been demonstrated with these filters. The fiber base material is alternately made from aluminosilicate fibers, zirconia fibers and alumina fibers. Coating with Al.sub.2 O.sub.3 is also described. Advanced configurations for the composite filter are suggested.

  2. Tier 2 Intermediate Useful Life (50,000 Miles) and 4000 Mile Supplemental Federal Test Procedure (SFTP) Exhaust Emission Results for a NOx Adsorber and Diesel Particle Filter Equipped Light-Duty Diesel Vehicle

    SciTech Connect

    Tatur, M.; Tyrer, H.; Tomazic, D.; Thornton, M.; McDonald, J.

    2005-01-01

    Due to its high efficiency and superior durability the diesel engine is again becoming a prime candidate for future light-duty vehicle applications within the United States. While in Europe the overall diesel share exceeds 40%, the current diesel share in the U.S. is 1%. Despite the current situation and the very stringent Tier 2 emission standards, efforts are being made to introduce the diesel engine back into the U.S. market. In order to succeed, these vehicles have to comply with emissions standards over a 120,000 miles distance while maintaining their excellent fuel economy. The availability of technologies such as high-pressure, common-rail fuel systems, low-sulfur diesel fuel, NO{sub x} adsorber catalysts (NAC), and diesel particle filters (DPFs) allow the development of powertrain systems that have the potential to comply with the light-duty Tier 2 emission requirements. In support of this, the U.S. Department of Energy (DOE) has engaged in several test projects under the Advanced Petroleum Based Fuels - Diesel Emission Controls (APBF-DEC) activity. The primary technology being addressed by these projects are the sulfur tolerance and durability of the NAC/DPF system. The project investigated the performance of the emission control system and system desulphurization effects on regulated and unregulated emissions. Emissions measurements were conducted over the Federal Test Procedure (FTP), Supplemental Federal Test Procedure (SFTP), and the Highway Fuel Economy Test (HFET). Testing was conducted after the accumulation of 150 hours of engine operation calculated to be the equivalent of approximately 8,200 miles. For these evaluations three out of six of the FTP test cycles were within the 50,000-mile Tier 2 bin 5 emission standards (0.05 g/mi NO{sub x} and 0.01 g/mi PM). Emissions over the SC03 portion of the SFTP were within the 4,000-mile SFTP standards. The emission of NO{sub x}+NMHC exceeded the 4,000-mile standard over the US06 portion of the SFTP

  3. Volumetric Modulation Arc Radiotherapy With Flattening Filter-Free Beams Compared With Static Gantry IMRT and 3D Conformal Radiotherapy for Advanced Esophageal Cancer: A Feasibility Study

    SciTech Connect

    Nicolini, Giorgia; Ghosh-Laskar, Sarbani; Shrivastava, Shyam Kishore; Banerjee, Sushovan; Chaudhary, Suresh; Agarwal, Jai Prakash; Munshi, Anusheel; Clivio, Alessandro; Fogliata, Antonella; Mancosu, Pietro; Vanetti, Eugenio; Cozzi, Luca

    2012-10-01

    Purpose: A feasibility study was performed to evaluate RapidArc (RA), and the potential benefit of flattening filter-free beams, on advanced esophageal cancer against intensity-modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3D-CRT). Methods and Materials: The plans for 3D-CRT and IMRT with three to seven and five to seven fixed beams were compared against double-modulated arcs with avoidance sectors to spare the lungs for 10 patients. All plans were optimized for 6-MV photon beams. The RA plans were studied for conventional and flattening filter-free (FFF) beams. The objectives for the planning target volume were the volume receiving {>=}95% or at most 107% of the prescribed dose of <1% with a dose prescription of 59.4 Gy. For the organs at risk, the lung volume (minus the planning target volume) receiving {>=}5 Gy was <60%, that receiving 20 Gy was <20%-30%, and the mean lung dose was <15.0 Gy. The heart volume receiving 45 Gy was <20%, volume receiving 30 Gy was <50%. The spinal dose received by 1% was <45 Gy. The technical delivery parameters for RA were assessed to compare the normal and FFF beam characteristics. Results: RA and IMRT provided equivalent coverage and homogeneity, slightly superior to 3D-CRT. The conformity index was 1.2 {+-} 0.1 for RA and IMRT and 1.5 {+-} 0.2 for 3D-CRT. The mean lung dose was 12.2 {+-} 4.5 for IMRT, 11.3 {+-} 4.6 for RA, and 10.8 {+-} 4.4 for RA with FFF beams, 18.2 {+-} 8.5 for 3D-CRT. The percentage of volume receiving {>=}20 Gy ranged from 23.6% {+-} 9.1% to 21.1% {+-} 9.7% for IMRT and RA (FFF beams) and 39.2% {+-} 17.0% for 3D-CRT. The heart and spine objectives were met by all techniques. The monitor units for IMRT and RA were 457 {+-} 139, 322 {+-} 20, and 387 {+-} 40, respectively. RA with FFF beams showed, compared with RA with normal beams, a {approx}20% increase in monitor units per Gray, a 90% increase in the average dose rate, and 20% reduction in beam on time (owing to different

  4. Filtering apparatus

    DOEpatents

    Haldipur, Gaurang B.; Dilmore, William J.

    1992-01-01

    A vertical vessel having a lower inlet and an upper outlet enclosure separated by a main horizontal tube sheet. The inlet enclosure receives the flue gas from a boiler of a power system and the outlet enclosure supplies cleaned gas to the turbines. The inlet enclosure contains a plurality of particulate-removing clusters, each having a plurality of filter units. Each filter unit includes a filter clean-gas chamber defined by a plate and a perforated auxiliary tube sheet with filter tubes suspended from each tube sheet and a tube connected to each chamber for passing cleaned gas to the outlet enclosure. The clusters are suspended from the main tube sheet with their filter units extending vertically and the filter tubes passing through the tube sheet and opening in the outlet enclosure. The flue gas is circulated about the outside surfaces of the filter tubes and the particulate is absorbed in the pores of the filter tubes. Pulses to clean the filter tubes are passed through their inner holes through tubes free of bends which are aligned with the tubes that pass the clean gas.

  5. Filtering apparatus

    DOEpatents

    Haldipur, G.B.; Dilmore, W.J.

    1992-09-01

    A vertical vessel is described having a lower inlet and an upper outlet enclosure separated by a main horizontal tube sheet. The inlet enclosure receives the flue gas from a boiler of a power system and the outlet enclosure supplies cleaned gas to the turbines. The inlet enclosure contains a plurality of particulate-removing clusters, each having a plurality of filter units. Each filter unit includes a filter clean-gas chamber defined by a plate and a perforated auxiliary tube sheet with filter tubes suspended from each tube sheet and a tube connected to each chamber for passing cleaned gas to the outlet enclosure. The clusters are suspended from the main tube sheet with their filter units extending vertically and the filter tubes passing through the tube sheet and opening in the outlet enclosure. The flue gas is circulated about the outside surfaces of the filter tubes and the particulate is absorbed in the pores of the filter tubes. Pulses to clean the filter tubes are passed through their inner holes through tubes free of bends which are aligned with the tubes that pass the clean gas. 18 figs.

  6. Filter component assessment

    SciTech Connect

    Alvin, M.A.; Lippert, T.E.; Diaz, E.S.; Smeltzer, E.W.

    1995-11-01

    The objectives of this program are to provide a more ruggedized filter system that utilizes porous ceramic filters which have improved resistance to damage resulting from crack propagation, thermal fatigue and/or thermal excursions during plant or process transient conditions, and/or mechanical ash bridging events within the candle filter array. As part of the current Phase 1, Task 1, effort of this program, Westinghouse is evaluating the filtration characteristics, mechanical integrity, and corrosion resistance of the following advanced or second generation candle filters for use in advanced coal-fired process applications: 3M CVI-SiC composite--chemical vapor infiltration of silicon carbide into an aluminosilicate Nextel{trademark} 312 fiber preform; DuPont PRD-66--filament wound candle filter structure containing corundum, cordierite, cristobalite, and mullite; DuPont SiC-SiC--chemical infiltration of silicon carbide into a silicon carbide Nicalon{trademark} fiber mat or felt preform; and IF and P Fibrosic{trademark}--vacuum infiltrated oxide-based chopped fibrous matrix. Results to date are presented.

  7. Effects of uniformities of deposition of respirable particles on filters on determining their quartz contents by using the direct on-filter X-ray diffraction (DOF XRD) method.

    PubMed

    Chen, Ching-Hwa; Tsaia, Perng-Jy; Lai, Chane-Yu; Peng, Ya-Lian; Soo, Jhy-Charm; Chen, Cheng-Yao; Shih, Tung-Sheng

    2010-04-15

    In this study, field samplings were conducted in three workplaces of a foundry plant, including the molding, demolding, and bead blasting, respectively. Three respirable aerosol samplers (including a 25-mm aluminum cyclone, nylon cyclone, and IOSH cyclone) were used side-by-side to collect samples from each selected workplace. For each collected sample, the uniformity of the deposition of respirable dusts on the filter was measured and its free silica content was determined by both the DOF XRD method and NIOSH 7500 XRD method (i.e., the reference method). A same trend in measured uniformities can be found in all selected workplaces: 25-mm aluminum cyclone>nylon cyclone>IOSH cyclone. Even for samples collected by the sampler with the highest uniformity (i.e., 25-mm aluminum cyclone), the use of the DOF XRD method would lead to the measured free silica concentrations 1.15-2.89 times in magnitude higher than that of the reference method. A new filter holder should be developed with the minimum uniformity comparable to that of NIOSH 7500 XRD method (=0.78) in the future. The use of conversion factors for correcting quartz concentrations obtained from the DOF XRD method based on the measured uniformities could be suitable for the foundry industry at this stage.

  8. Contactor/filter improvements

    DOEpatents

    Stelman, David

    1989-01-01

    A contactor/filter arrangement for removing particulate contaminants from a gaseous stream includes a housing having a substantially vertically oriented granular material retention member with upstream and downstream faces, a substantially vertically oriented microporous gas filter element, wherein the retention member and the filter element are spaced apart to provide a zone for the passage of granular material therethrough. The housing further includes a gas inlet means, a gas outlet means, and means for moving a body of granular material through the zone. A gaseous stream containing particulate contaminants passes through the gas inlet means as well as through the upstream face of the granular material retention member, passing through the retention member, the body of granular material, the microporous gas filter element, exiting out of the gas outlet means. Disposed on the upstream face of the filter element is a cover screen which isolates the filter element from contact with the moving granular bed and collects a portion of the particulates so as to form a dust cake having openings small enough to exclude the granular material, yet large enough to receive the dust particles. In one embodiment, the granular material is comprised of prous alumina impregnated with CuO, with the cover screen cleaned by the action of the moving granular material as well as by backflow pressure pulses.

  9. Kalman filter-based fast track reconstruction for charged particles in a Compressed Baryonic Matter experiment using parallel computing on a multicore server at the Laboratory of Information Technologies, Joint Institute for Nuclear Research

    NASA Astrophysics Data System (ADS)

    Ablyazimov, T. O.; Zyzak, M. V.; Ivanov, V. V.; Kisel, P. I.

    2015-05-01

    One of the main goals in the Compressed Baryonic Matter (CBM) experiment (GSI, Germany) is to find parameters of charged particle trajectories. An online full event reconstruction is planned to be carried out in this experiment, thus demanding fast algorithms be developed, which make the most of the capabilities of modern CPU and GPU architectures. This paper presents the results of an analysis of the Kalman filter-based track reconstruction for charged particles implemented by using various code parallelization methods. A multicore server located at the Laboratory of Information Technologies, Joint Institute for Nuclear Research (LIT JINR), with two CPU Intel Xeon X5660 processors and a GPU Nvidia GTX 480 video card is used.

  10. EFFECT OF CENTRAL FANS AND IN-DUCT FILTERS ON DEPOSITION RATES OF ULTRAFINE AND FINE PARTICLES IN AN OCCUPIED TOWNHOUSE

    EPA Science Inventory

    Airborne particles are implicated in morbidity and mortality of certain high-risk subpopulations. Exposure to particles occurs mostly indoors, where a main removal mechanism is deposition to surfaces. Deposition can be affected by the use of forced- air circulation through duct...

  11. Ultraviolet filters.

    PubMed

    Shaath, Nadim A

    2010-04-01

    The chemistry, photostability and mechanism of action of ultraviolet filters are reviewed. The worldwide regulatory status of the 55 approved ultraviolet filters and their optical properties are documented. The photostabilty of butyl methoxydibenzoyl methane (avobenzone) is considered and methods to stabilize it in cosmetic formulations are presented.

  12. Recent advances in particle and droplet manipulation for lab-on-a-chip devices based on surface acoustic waves.

    PubMed

    Wang, Zhuochen; Zhe, Jiang

    2011-04-07

    Manipulation of microscale particles and fluid liquid droplets is an important task for lab-on-a-chip devices for numerous biological researches and applications, such as cell detection and tissue engineering. Particle manipulation techniques based on surface acoustic waves (SAWs) appear effective for lab-on-a-chip devices because they are non-invasive, compatible with soft lithography micromachining, have high energy density, and work for nearly any type of microscale particles. Here we review the most recent research and development of the past two years in SAW based particle and liquid droplet manipulation for lab-on-a-chip devices including particle focusing and separation, particle alignment and patterning, particle directing, and liquid droplet delivery.

  13. Automated classification of single airborne particles from two-dimensional angle-resolved optical scattering (TAOS) patterns by non-linear filtering

    NASA Astrophysics Data System (ADS)

    Crosta, Giovanni Franco; Pan, Yong-Le; Aptowicz, Kevin B.; Casati, Caterina; Pinnick, Ronald G.; Chang, Richard K.; Videen, Gorden W.

    2013-12-01

    Measurement of two-dimensional angle-resolved optical scattering (TAOS) patterns is an attractive technique for detecting and characterizing micron-sized airborne particles. In general, the interpretation of these patterns and the retrieval of the particle refractive index, shape or size alone, are difficult problems. By reformulating the problem in statistical learning terms, a solution is proposed herewith: rather than identifying airborne particles from their scattering patterns, TAOS patterns themselves are classified through a learning machine, where feature extraction interacts with multivariate statistical analysis. Feature extraction relies on spectrum enhancement, which includes the discrete cosine FOURIER transform and non-linear operations. Multivariate statistical analysis includes computation of the principal components and supervised training, based on the maximization of a suitable figure of merit. All algorithms have been combined together to analyze TAOS patterns, organize feature vectors, design classification experiments, carry out supervised training, assign unknown patterns to classes, and fuse information from different training and recognition experiments. The algorithms have been tested on a data set with more than 3000 TAOS patterns. The parameters that control the algorithms at different stages have been allowed to vary within suitable bounds and are optimized to some extent. Classification has been targeted at discriminating aerosolized Bacillus subtilis particles, a simulant of anthrax, from atmospheric aerosol particles and interfering particles, like diesel soot. By assuming that all training and recognition patterns come from the respective reference materials only, the most satisfactory classification result corresponds to 20% false negatives from B. subtilis particles and <11% false positives from all other aerosol particles. The most effective operations have consisted of thresholding TAOS patterns in order to reject defective ones

  14. Comparison of advanced DSP techniques for spectrally efficient Nyquist-WDM signal generation using digital FIR filters at transmitters based on higher-order modulation formats

    NASA Astrophysics Data System (ADS)

    Weng, Yi; Wang, Junyi; Pan, Zhongqi

    2016-02-01

    To support the ever-increasing demand for high-speed optical communications, Nyquist spectral shaping serves as a promising technique to improve spectral efficiency (SE) by generating near-rectangular spectra with negligible crosstalk and inter-symbol interference in wavelength-division-multiplexed (WDM) systems. Compared with specially-designed optical methods, DSP-based electrical filters are more flexible as they can generate different filter shapes and modulation formats. However, such transmitter-side pre-filtering approach is sensitive to the limited taps of finite-impulse-response (FIR) filter, for the complexity of the required DSP and digital-to-analog converter (DAC) is limited by the cost and power consumption of optical transponder. In this paper, we investigate the performance and complexity of transmitter-side FIR-based DSP with polarization-division-multiplexing (PDM) high-order quadrature-amplitude-modulation (QAM) formats. Our results show that Nyquist 64-QAM, 16-QAM and QPSK WDM signals can be sufficiently generated by digital FIR filters with 57, 37, and 17 taps respectively. Then we explore the effects of the required spectral pre-emphasis, bandwidth and resolution on the performance of Nyquist-WDM systems. To obtain negligible OSNR penalty with a roll-off factor of 0.1, two-channel-interleaved DAC requires a Gaussian electrical filter with the bandwidth of 0.4-0.6 times of the symbol rate for PDM-64QAM, 0.35-0.65 times for PDM-16QAM, and 0.3-0.8 times for PDM-QPSK, with required DAC resolutions as 8, 7, 6 bits correspondingly. As a tradeoff, PDM-64QAM can be a promising candidate for SE improvement in next-generation optical metro networks.

  15. THE INFLUENCE OF HUMAN ACTIVITY PATTERNS ON PERSONAL PM EXPOSURE: A COMPARATIVE ANALYSIS OF FILTER-BASED AND CONTINUOUS PARTICLE MEASUREMENTS

    EPA Science Inventory

    Particulate matter (PM) exposure data from the U.S. Environmental Protection Agency sponsored 1998 Baltimore and 1999 Fresno PM Exposure Studies were analyzed to identify important microenvironments and activities that may lead to increased particle exposure for select elderly ...

  16. Electric filter with movable belt electrode

    DOEpatents

    Bergman, Werner

    1983-01-01

    A method and apparatus for removing airborne contaminants entrained in a gas or airstream includes an electric filter characterized by a movable endless belt electrode, a grounded electrode, and a filter medium sandwiched therebetween. Inclusion of the movable, endless belt electrode provides the driving force for advancing the filter medium through the filter, and reduces frictional drag on the filter medium, thereby permitting a wide choice of filter medium materials. Additionally, the belt electrode includes a plurality of pleats in order to provide maximum surface area on which to collect airborne contaminants.

  17. Electric filter with movable belt electrode

    DOEpatents

    Bergman, W.

    1983-09-20

    A method and apparatus for removing airborne contaminants entrained in a gas or airstream includes an electric filter characterized by a movable endless belt electrode, a grounded electrode, and a filter medium sandwiched there between. Inclusion of the movable, endless belt electrode provides the driving force for advancing the filter medium through the filter, and reduces frictional drag on the filter medium, thereby permitting a wide choice of filter medium materials. Additionally, the belt electrode includes a plurality of pleats in order to provide maximum surface area on which to collect airborne contaminants. 4 figs.

  18. Evaluation of the effect of media velocity on HEPA filter performance

    SciTech Connect

    Alderman, Steven; Parsons, Michael; Hogancamp, Kristina; Norton, O. Perry; Waggoner, Charles

    2007-07-01

    Section FC of the ASME AG-1 Code addresses glass fiber HEPA filters and restricts the media velocity to a maximum of 2.54 cm/s (5 ft/min). Advances in filter media technology allow glass fiber HEPA filters to function at significantly higher velocities and still achieve HEPA performance. However, diffusional capture of particles < 100 nm is reduced at higher media velocities due to shorter residence times within the media matrix. Therefore, it is unlikely that higher media velocities for HEPA filters will be allowed without data to demonstrate the effect of media velocity on removal of particles in the smaller size classes. In order to address this issue, static testing has been conducted to generate performance related data and a range of dynamic testing has provided data regarding filter lifetimes, loading characteristics, changes in filter efficiency and the most penetrating particle size over time. Testing was conducted using 31 cm x 31 cm x 29 cm deep pleat HEPA filters supplied from two manufacturers. Testing was conducted at media velocities ranging from 2.0-4.5 cm/s with a solid aerosol challenge composed of potassium chloride. Two set of media velocity data were obtained for each filter type. In one set of evaluations, the maximum aerosol challenge particle size was limited to 3 {mu}m, while particles above 3 {mu}m were not constrained in the second set. This provided for considerable variability in the challenge mass mean diameter and overall mass loading rate. Results of this testing will be provided to the ASME AG-1 FC Committee for consideration in future versions of the HEPA standard. In general, the initial filter efficiency decreased with increasing media velocity. However, initial filter efficiencies were generally good in all cases. Filter efficiency values averaged over the first ten minute of the loading cycle ranged from 99.970 to 99.996 %. Additionally, the most penetrating particle size was observed to decrease with increasing media velocity

  19. Optical iconic filters for large class recognition.

    PubMed

    Casasent, D; Mahalamobis, A

    1987-06-01

    Approaches are advanced for pattern recognition when a large number of classes must be identified. Multilevel encoded multiple-iconic filters are considered for this problem. Hierarchical arrangements of iconic filters and/or preprocessing stages are described. A theoretical basis for the sidelobe level and noise effects of filters designed for large class problems is advanced. Experimental data are provided for an optical character recognition case study.

  20. Semi-continuous sampling of health relevant atmospheric particle subfractions for chemical speciation using a rotating drum impactor in series with sequential filter sampler.

    PubMed

    Li, Fengxia; Schnelle-Kreis, Jürgen; Karg, Erwin; Cyrys, Josef; Gu, Jianwei; Orasche, Jürgen; Abbaszade, Gülcin; Peters, Annette; Zimmermann, Ralf

    2016-04-01

    To achieve unattended continuous long-term (eg., 1 week) sampling of size-segregated 24-h ambient particulate matter (PM), a sampling strategy of a modified 3-stage rotating drum impactor (RDI) in series with a sequential filter sampler was introduced and verified in a field campaign. Before the field sampling, lab experiment was conducted to test the collection efficiency of the third stage of the RDI using the quartz-fiber filter (QFF) as the substrate. The measured value is 0.36 μm, which is larger than the nominal value 0.1 μm. A fast direct analysis of organic species in all size fractions (<0.36, 0.36-1, 1-2.4, and 2.4-10 μm) of 24-h ambient samples was done using in situ derivatization thermal desorption gas chromatography time-of-flight mass spectrometry (IDTD-GC-TOFMS). A few secondary originated polar markers (dicarboxylic acids, cis-pinonic acid, etc.) were introduced and evaluated using this method for the first t