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Sample records for hot-gas filter development

  1. ADVANCED HOT GAS FILTER DEVELOPMENT

    Energy Technology Data Exchange (ETDEWEB)

    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

  2. ADVANCED HOT GAS FILTER DEVELOPMENT

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. ADVANCED HOT GAS FILTER DEVELOPMENT

    Energy Technology Data Exchange (ETDEWEB)

    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.

  4. Development of iron-aluminide hot-gas filters

    Energy Technology Data Exchange (ETDEWEB)

    Tortorelli, P.F.; Wright, I.G.; Judkins, R.R.

    1996-06-01

    Removal of particles from hot synthesis gas produced by coal gasification is vital to the success of these systems. In Integrated [Coal] Gasification Combined Cycle systems, the synthesis gas is the fuel for gas turbines. To avoid damage to turbine components, it is necessary that particles be removed from the fuel gas prior to combustion and introduction into the turbine. Reliability and durability of the hot-gas filtering devices used to remove the particles is, of course, of special importance. Hot-gas filter materials include both ceramics and metals. Numerous considerations must be made in selecting materials for these filters. Constituents in the hot gases may potentially degrade the properties and performance of the filters to the point that they are ineffective in removing the particles. Very significant efforts have been made by DOE and others to develop effective hot-particle filters and, although improvements have been made, alternative materials and structures are still needed.

  5. Ceramic hot-gas filter

    Science.gov (United States)

    Connolly, Elizabeth Sokolinski; Forsythe, George Daniel; Domanski, Daniel Matthew; Chambers, Jeffrey Allen; Rajendran, Govindasamy Paramasivam

    1999-01-01

    A ceramic hot-gas candle filter having a porous support of filament-wound oxide ceramic yarn at least partially surrounded by a porous refractory oxide ceramic matrix, and a membrane layer on at least one surface thereof. The membrane layer may be on the outer surface, the inner surface, or both the outer and inner surface of the porous support. The membrane layer may be formed of an ordered arrangement of circularly wound, continuous filament oxide ceramic yarn, a ceramic filler material which is less permeable than the filament-wound support structure, or some combination of continuous filament and filler material. A particularly effective membrane layer features circularly wound filament with gaps intentionally placed between adjacent windings, and a filler material of ceramic particulates uniformly distributed throughout the gap region. The filter can withstand thermal cycling during backpulse cleaning and is resistant to chemical degradation at high temperatures.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Process for making ceramic hot gas filter

    Science.gov (United States)

    Connolly, Elizabeth Sokolinski; Forsythe, George Daniel; Domanski, Daniel Matthew; Chambers, Jeffrey Allen; Rajendran, Govindasamy Paramasivam

    2001-01-01

    A ceramic hot-gas candle filter having a porous support of filament-wound oxide ceramic yarn at least partially surrounded by a porous refractory oxide ceramic matrix, and a membrane layer on at least one surface thereof. The membrane layer may be on the outer surface, the inner surface, or both the outer and inner surface of the porous support. The membrane layer may be formed of an ordered arrangement of circularly wound, continuous filament oxide ceramic yarn, a ceramic filler material which is less permeable than the filament-wound support structure, or some combination of continuous filament and filler material. A particularly effective membrane layer features circularly wound filament with gaps intentionally placed between adjacent windings, and a filler material of ceramic particulates uniformly distributed throughout the gap region. The filter can withstand thermal cycling during backpulse cleaning and is resistant to chemical degradation at high temperatures.

  8. Advanced hot gas filter development. Topical report, May 1995--December 1996

    Energy Technology Data Exchange (ETDEWEB)

    Hurley, J.L.; June, M.R.

    1997-12-31

    Porous iron aluminide was evaluated for use as a particulate filter in pressurized fluid-bed combustion (PFBC) and integrated gasification combined cycles (IGCC) with a short term test. Three alloy compositions were tested: Fe{sub 3}Al 5% chromium (FAL), Fe{sub 3}Al 2% chromium (FAS) and FeAl 0% chromium. The test conditions simulated air blown (Tampa Electric) and oxygen blown (Sierra Pacific) gasifiers with one test gas composition. Four test conditions were used with hydrogen sulfide levels varying from 783 ppm to 78,3000 ppm at 1 atmosphere along with temperatures ranging between 925 F and 1200 F. The iron aluminide was found capable of withstanding the proposed operating conditions and capable of giving years of service. The production method and preferred composition were established as seamless cylinders of Fe{sub 3}Al 2% chromium with a preoxidation of seven hours at 1472 F.

  9. Development and characterization of Textron continuous fiber ceramic composite hot gas filter materials. Final report, September 30, 1994--October 31, 1997

    Energy Technology Data Exchange (ETDEWEB)

    DiPietro, S.G.; Alvin, M.A.

    1997-12-31

    Uncertainties about the long-term ability of monolithic ceramics to survive in the IGCC or PFBC hot gas filter environment led DOE/METC to consider the merits of using continuous fiber reinforced ceramic composites (CFCCs) as potential next-generation high temperature filter elements. This seems to be a logical strategy to pursue in light of the fact that properly-engineered CFCC materials have shown much-improved damage tolerance and thermal shock behavior as compared to existing monolithic ceramic materials. Textron`s Advanced Hot Gas Filter Development Program was intended to be a two year, two phase program which transitioned developmental materials R and D into prototype filter element fabrication. The first phase was to demonstrate the technical feasibility of fabricating CFCC hot gas filter elements which could meet the pressure drop specifications of less than ten inches of water (iwg) at a face velocity of ten feet per minute (fpm), while showing sufficient integrity to survive normal mechanical loads and adequate environmental resistance to steam/alkali corrosion conditions at a temperature of approximately 870 C (1600 F). The primary objective of the second phase of the program was to scale up fabrication methods developed in Phase 1 to produce full-scale CFCC candle filters for validation testing. Textron encountered significant process-related and technical difficulties in merely meeting the program permeability specifications, and much effort was expended in showing that this could indeed be achieved. Thus, by the time the Phase 1 program was completed, expenditure of program funds precluded continuing on with Phase 2, and Textron elected to terminate their program after Phase 1. This allowed Textron to be able to focus technical and commercialization efforts on their largely successful DOE CFCC Program.

  10. Factors affecting dustcake drag in a hot-gas filter system collecting coal gasification ash

    Energy Technology Data Exchange (ETDEWEB)

    Dahlin, R.S.; Landham, E.C. [Power Systems Development Facility, Wilsonville, AL (United States)

    2008-01-15

    This paper discusses the use of laboratory drag measurements and filter operating data to analyze factors affecting dustcake flow resistance in a hot-gas filter at the Power Systems Development Facility (PSDF). The hot-gas filter is a Siemens-Westinghouse two-tier candle filter system that is collecting coal gasification ash from a KBR Transport Gasifier. Operating experience with this system has shown that the flow resistance of the dustcake is responsible for most of the pressure drop across the hot-gas filter, and the pressure drop varies substantially with the type of coal being gasified and the operating conditions of the gasifier and filter systems. To analyze factors affecting dustcake drag, samples of gasification ash from various coals and various operating conditions were resuspended in a laboratory test apparatus, and the drag was measured as the dust was collected on a sintered metal filter. The lab-measured drag values were compared to actual values of transient drag determined from the increase in pressure drop, the inlet dust loading, and the face velocity in the hot-gas filter. After correcting the lab drag data to hot-gas filter conditions, good agreement was achieved between the lab measurements and the hot-gas filter transient drag values. Both types of measurements showed that drag was strongly influenced by coal type and carbon content.

  11. Mechanical behavior of ceramic composite hot-gas filters after exposure to severe environments

    Energy Technology Data Exchange (ETDEWEB)

    Pysher, D.J.; Weaver, B.L.; Smith, R.G. [Ceramic Technology Center, St. Paul, MN (United States)] [and others

    1995-08-01

    A novel type of hot-gas filter based on a ceramic fiber reinforced ceramic matrix has been developed, as reported at previous Fossil Energy Materials Conferences, through research activities at Oak Ridge National Laboratory (ORNL) and at the 3M Company. Simulated testing has been done at the Westinghouse Science and Technology Center. This filter technology has been extended to full size, 60 mm OD by 1.5 meter long candle filters and a commercially viable process for producing the filters has been developed filters are undergoing testing and demonstration use throughout the world for applications in pressurized fluidized-bed combustion (PFBC) and integrated gasification combined cycle (IGCC) plants. Demonstration tests of this ceramic composite filter along with other filters are in progress at the Tidd PFBC plant Mechanical tests were performed on the 3 M brand Ceramic Composite Candle Filter after exposure to various corrosive environments in order to assess its ability to function as a hot gas filter in coal-fired applications. Due to the different construction of ceramic composite filters and the thin composite wall versus the typical thick-walled monolithic filter, standard mechanical property tests had to be refined or modified to accurately determine the filters properties. These tests and filter property results will be described Longitudinal tensile and diametral O-ring compression tests were performed on as-produced candle filters as well as on filters which had been exposed to various environments. The exposures were for 1000 hrs at 850{degrees}C in wet air, in wet air containing Na{sub 2}CO{sub 3}, and in wet air containing NaCl. In addition, a filter which bad been coated with ash (Old Grimethorpe) was exposed to wet air at 850{degrees}C for 1000 hours.

  12. Fiber-reinforced composite hot-gas filters

    Science.gov (United States)

    Stinton, D. P.; Lowden, R. A.; Chang, R.

    1987-05-01

    A chemical vapor deposition process was developed for the fabrication of high-temperature particulate filters. Fibrous materials such as Nicalon (SiC) felt and aluminosilicate papers were used as the filter material. Preliminary evaluation of filter specimens fabricated from Nicalon revealed extremely encouraging results. Cleanable filters with collection efficiencies of greater than 99.9% were recorded for both PFBC flyash and gasifier char.

  13. Automated nondestructive evaluation method for characterizing ceramic and metallic hot gas filters.

    Energy Technology Data Exchange (ETDEWEB)

    Ellingson, W. A.; Koehl, E. R.; Deemer, C.; Pastilla, P.; Wheeler, B.; Forster, G. A.

    2002-06-03

    In advanced coal-fired power generation, one technology under development to clean up hot gases before their use as fuel for gas turbines is rigid ceramic candle filters. These porous filters are typically 1.5 m long and 60 mm in diameter and are made of various ceramic materials, including clay-bonded SiC. The high costs of downtime in a large utility demands that nondestructive evaluation/characterization (NDE/C) methods be available. At shutdowns, data from such analysis are needed to decide which filters are still usable and which need to be replaced, and if possible, to estimate the remaining lifetimes. Thus our objective was to develop reliable low-cost NDE technology for these filters. Our approach was to develop NDE/C technology, referred to as acousto-ultrasonics (AU), for application to hot gas filters. Lamb waves generated by the AU method were analyzed to derive a stress wave factor (SWF). This technology was tested by comparing SWF data with the measured strength for a variety of rigid ceramic filters and was shown to work on iron-aluminide filters as well but no strength data have been obtained on the iron-aluminides at this time.

  14. High temperature corrosion of advanced ceramic materials for hot gas filters. Topical report for part 1 of high temperature corrosion of advanced ceramic materials for hot gas filters and heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Spear, K.E.; Crossland, C.E.; Shelleman, D.L.; Tressler, R.E. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering

    1997-12-11

    This program consists of two separate research areas. Part 1, for which this report is written, studied the high temperature corrosion of advanced ceramic hot gas filters, while Part 2 studied the long-term durability of ceramic heat exchangers to coal combustion environments. The objectives of Part 1 were to select two candidate ceramic filter materials for flow-through hot corrosion studies and subsequent corrosion and mechanical properties characterization. In addition, a thermodynamic database was developed so that thermochemical modeling studies could be performed to simulate operating conditions of laboratory reactors and existing coal combustion power plants, and to predict the reactions of new filter materials with coal combustion environments. The latter would make it possible to gain insight into problems that could develop during actual operation of filters in coal combustion power plants so that potential problems could be addressed before they arise.

  15. Hot gas cleanup using ceramic cross flow membrane filters. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Ciliberti, D.F.; Smeltzer, E.E.; Alvin, M.A.; Keairns, D.L.; Bachovchin, D.M.

    1983-12-01

    The single unresolved technical issue in the commercialization of pressurized fluid-bed combustion (PPBC) for electric power production is the hot gas cleaning problem. In this technology, high-temperature and -pressure (HTHP), dust-laden flue gases from the combustor must be cleaned enough to reduce expansion turbine blade erosion to an economically acceptable level. Additionally, the level of particulate emission must be compatible with the New Source Performance Standards (NSPS) for environmental acceptability. The Department of Energy (DOE) has sponsored a wide range of research and development programs directed at the solution of this problem. These programs were divided into two classifications, one dealing with more advanced concepts where testing was to be done at relatively large scale and a second group of less advanced, novel concepts where the testing was to be carried out at a bench scale. The cross-flow ceramic membrane filter program described in this report is a member of the small-scale, novel concept group.

  16. Thermal-shock behavior of advanced ceramic/composite hot-gas filters

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-02-01

    The thermal shock/fatigue behavior of monolithic and composite hot-gas candle filters obtained from various manufacturers was evaluated. The composite filters were made of both oxide and nonoxide materials; the monolithic filters were made only of nonoxide materials. During single-cycle thermal shock tests, composite filters show little or no strength degradation when quenched from temperatures between 900 and 1000{degrees}C. At higher quenching temperatures, slow strength degradation was observed. Regular monolithic SiC filters showed no strength degradation when quenched from temperatures up to {approx}700-900{degrees}C, whereas at higher quenching temperatures, the strength decreased at a relatively sharper rate. On the other hand, recrystallized monolithic SiC filters showed higher initial strength and retained this strength to higher quenching temperatures when compared with regular SiC filters. This finding may be related to the difference in the strength of grain boundary phases in the two filters. For thermal cycles between room temperature and 800-1000{degrees}C, composite filters show little (18-24%) strength degradation up to three cycles, beyond which the strength remains unchanged. Similar behavior, with an initial strength drop of 15-28%, was observed for monolithic filter specimens that were thermally cycled between room temperature and 800{degrees}C.

  17. Method of making a continuous ceramic fiber composite hot gas filter

    Science.gov (United States)

    Hill, Charles A.; Wagner, Richard A.; Komoroski, Ronald G.; Gunter, Greg A.; Barringer, Eric A.; Goettler, Richard W.

    1999-01-01

    A ceramic fiber composite structure particularly suitable for use as a hot gas cleanup ceramic fiber composite filter and method of making same from ceramic composite material has a structure which provides for increased strength and toughness in high temperature environments. The ceramic fiber composite structure or filter is made by a process in which a continuous ceramic fiber is intimately surrounded by discontinuous chopped ceramic fibers during manufacture to produce a ceramic fiber composite preform which is then bonded using various ceramic binders. The ceramic fiber composite preform is then fired to create a bond phase at the fiber contact points. Parameters such as fiber tension, spacing, and the relative proportions of the continuous ceramic fiber and chopped ceramic fibers can be varied as the continuous ceramic fiber and chopped ceramic fiber are simultaneously formed on the porous vacuum mandrel to obtain a desired distribution of the continuous ceramic fiber and the chopped ceramic fiber in the ceramic fiber composite structure or filter.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kupp, E.R.; Trubelja, M.F.; Spear, K.E.; Tressler, R.E. [Pennsylvania State Univ., University Park, PA (United States)

    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.

  19. Hot-gas cleanup system model development. Volume II. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Ushimaru, K.; Bennett, A.; Bekowies, P.J.

    1982-11-01

    Under Contract to the Department of Energy (DOE) through the Morgantown Energy Technology Center (METC), Flow Industries, Inc., has developed computer models to simulate the physical performance of five hot-gas cleanup devices for pressurized, fluidized-bed combustion (PFBC), combined-cycle power plants. Separate cost models have also been developed to estimate the cost of each device. The work leading to the development of these models is described in Volume I of this report. This volume contains the user's manuals for both the physical and cost models. The manuals for the physical models are given first followed by those for the cost models. Each manual is a complete and separate document. The model names and devices and their respective subroutine names are: (1) Moving Granular Bed Filter by Combustion Power Company, USRCGB, QFCOST; (2) Ceramic Bag Filter by Acurex, USRACB, QDCOST; (3) Electrostatic Granular Bed Filter by General Electric, USRGGB, QACOST; (4) Electrostatic Precipitator by Research Cottrell, USRCEP, QECOST; and (5) Electrocyclone by General Electric, USRGCY, QBCOST.

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

    Energy Technology Data Exchange (ETDEWEB)

    Crossland, C.E.; Shelleman, D.L.; Spear, K.E. [Pennsylvania State Univ., University Park, PA (United States)] [and others

    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.

  1. Evaluation of an all-ceramic tubesheet assembly for a hot gas filter

    Energy Technology Data Exchange (ETDEWEB)

    Bitner, J.L. [Mallett Technology, Inc., Canonsburg, PA (United States); Mallett, R.H. [Mallett Technology, Inc., Research Triangle Park, NC (United States); Eggerstedt, P.M. [Industrial Filter and Pump Mfg. Co., Cicero, IL (United States); Swindeman, R.W. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    A 10-inch thick, all-ceramic tubesheet design is evaluated for differential pressure and thermal conditions. Primary stresses from differential pressure are well within a safe allowable. The calculated peak thermal stresses at local discontinuities approach the modules of rupture for the ceramic material. Kiln tests were performed to demonstrate differential temperatures between hot center and cooler rim do not cause failures or visible tensile cracks. There appear to be mitigating mechanisms and design features in the Industrial Filter and Pump (IF and P) Mfg. Co. all-ceramic tubesheet design concept that add forgiveness in accommodating differential pressure and thermal loading stresses. A material characterization program on the ceramic materials is recommended.

  2. Advances in hot gas filtration technology

    Energy Technology Data Exchange (ETDEWEB)

    Weber, C.

    The past decade has seen the introduction of new filter media specifically designed for 'hot-gas' filtration. These media are available as woven or knitted fabrics and as non-wovens, i.e. needled felts. Needlefelted fabrics have proven so highly successful in the dedusting of hot gases that they are widely used nowadays in this new and necessary technology. Hot-gas filtration offers advantages in, for example, the saving or recycling of energy, the elimination of the cooling process, and the short-circuiting of process steps. This paper gives a survey of the types of textile fibres available for hot-gas filtration from the more recently developed organic fibres to refractory fibres. It describes, compares and contrasts their salient properties and lists the uses to which they may be put. It concentrates on such fibres which are generally referred to as 'high performance materials', since they are expected to provide satisfactory performance under extreme conditions of temperature, chemical environment and mechanical stress. It touches on filtration theory governing the collection mechanism. 9 refs., 7 figs., 3 tabs.

  3. Hot-gas cleanup system model development. Volume I. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Ushimaru, K.; Bennett, A.; Bekowies, P.J.

    1982-11-01

    This two-volume report summarizes the state of the art in performance modeling of advanced high-temperature, high-pressure (HTHP) gas cleanup devices. Volume I contains the culmination of the research effort carried over the past 12 months and is a summary of research achievements. Volume II is the user's manual for the computer programs developed under the present research project. In this volume, Section 2 presents background information on pressurized, fluidized-bed combustion concepts, a description of the role of the advanced gas cleanup systems, and a list of advanced gas cleanup systems that are currently in development under DOE sponsorship. Section 3 describes the methodology for the software architecture that forms the basis of the well-disciplined and structured computer programs developed under the present project. Section 4 reviews the fundamental theories that are important in analyzing the cleanup performance of HTHP gas filters. Section 5 discusses the effect of alkali agents in HTHP gas cleanup. Section 6 evaluates the advanced HTHP gas cleanup models based on their mathematical integrity, availability of supporting data, and the likelihood of commercialization. As a result of the evaluation procedure detailed in Section 6, five performance models were chosen to be incorporated into the overall system simulation code, ASPEN. These five models (the electrocyclone, ceramic bag filter, moving granular bed filter, electrostatic granular bed filter, and electrostatic precipitator) are described in Section 7. The method of cost projection for these five models is discussed in Section 8. The supporting data and validation of the computer codes are presented in Section 9, and finally the conclusions and recommendations for the HTHP gas cleanup system model development are given in Section 10. 72 references, 19 figures, 25 tables.

  4. Evaluation of mechanical properties and structural changes of ceramic filter materials for hot gas cleaning under simulated process conditions

    OpenAIRE

    Westerheide, R.; Wehd, C. von der; Rehak, P.; Adler, J.

    2002-01-01

    In the combined cycle technology for advanced coal fired power plants at high temperatures up to 950 °C the removal of particles from the stream to the gas turbine is carried out with ceramic filter elements. These elements consist often of siliceous bonded coarse grained silicon carbide. A stable long term operation of the filter elements leads to the demands on good resistance towards thermal, mechanical and chemical loading. The structure of ceramic filter elements consists usually of a hi...

  5. PARTICULATE HOT GAS STREAM CLEANUP TECHNICAL ISSUES

    Energy Technology Data Exchange (ETDEWEB)

    None

    1999-02-26

    This quarterly report describes technical activities performed under Contract No. DE-AC21-94MC31160. The analyses of hot gas stream cleanup (HGCU) ashes and descriptions of filter performance studied under Task 1 of this contract are designed to address problems with filter operation that are apparently linked to characteristics of the collected ash. This report includes a description of a device developed to harden a filter cake on a filter element so that the element and cake can subsequently be encapsulated in epoxy and studied in detail. This report also reviews the status of the HGCU data base of ash and char characteristics. Task 1 plans for the remainder of the project include characterization of additional samples collected during site visits to the Department of Energy/Southern Company Services Power Systems Development Facility (PSDF), encapsulation of an intact filter cake from the PSDF, and completion and delivery of the HGCU data bank. Task 2 of this project concerns the testing and failure analyses of new and used filter elements and filter materials. Task 2 work during the past quarter consisted of hoop tensile and axial compressive stress-strain responses of McDermott ceramic composite and hoop tensile testing of Techniweave candle filters as-manufactured and after exposure to the gasification environment.

  6. Particulate hot gas stream cleanup technical issues

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-01

    This is the tenth in a series of quarterly reports describing the activities performed under Contract No. DE-AC21-94MC31160. Analyses of Hot Gas Stream Cleanup (HGCU) ashes and descriptions of filter performance address aspects of filter operation that are apparently linked to the characteristics of the collected ash or the performance of the ceramic bed filter elements. Task I is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters (APFS) and to relate these ash properties to the operation and performance of these filters. Task 2 concerns testing and failure analysis of ceramic filter elements. Under Task I during the past quarter, analyses were performed on a particulate sample from the Transport Reactor Demonstration Unit (TRDU) located at the University of North Dakota Energy and Environmental Research Center. Analyses are in progress on ash samples from the Advanced Particulate Filter (APF) at the Pressurized Fluidized-Bed Combustor (PFBC) that was in operation at Tidd and ash samples from the Pressurized Circulating Fluid Bed (PCFB) system located at Karhula, Finland. A site visit was made to the Power Systems Development Facility (PSDF) to collect ash samples from the filter vessel and to document the condition of the filter vessel with still photographs and videotape. Particulate samples obtained during this visit are currently being analyzed for entry into the Hot Gas Cleanup (HGCU) data base. Preparations are being made for a review meeting on ash bridging to be held at Department of Energy Federal Energy Technology Center - Morgantown (DOE/FETC-MGN) in the near future. Most work on Task 2 was on hold pending receipt of additional funds; however, creep testing of Schumacher FT20 continued. The creep tests on Schumacher FT20 specimens just recently ended and data analysis and comparisons to other data are ongoing. A summary and analysis of these creep results will be sent out shortly. Creep

  7. PARTICULATE HOT GAS STREAM CLEANUP TECHNICAL ISSUES

    Energy Technology Data Exchange (ETDEWEB)

    None

    1999-05-05

    This is the fourth annual report describing the activities performed under Task 1 of Contract No. DE-AC21-94MC31160. The analyses of hot gas stream cleanup (HGCU) ashes and descriptions of filter performance studied under this contract are designed to address problems with filter operation that are apparently linked to characteristics of the collected ash. This work is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters and to relate these ash properties to the operation and performance of these filters and their components. This report summarizes characterizations of ash and char samples from pressurized fluidized-bed combustion and gasification facilities. Efforts are under way to develop a method for preserving fragile filter cakes formed on ceramic filter elements. The HGCU data base was formatted for Microsoft Access 97 ® . Plans for the remainder of the project include characterization of additional samples collected during site visits to the Department of Energy / Southern Company Services Power Systems Development Facility and completion and delivery of the HGCU data base.

  8. PARTICULATE HOT GAS STREAM CLEANUP TECHNICAL ISSUES

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-11-30

    This is the fourth annual report describing the activities performed under Task 1 of Contract No. DE-AC21-94MC31160. The analyses of hot gas stream cleanup (HGCU) ashes and descriptions of filter performance studied under this contract are designed to address problems with filter operation that are apparently linked to characteristics of the collected ash. This work is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters and to relate these ash properties to the operation and performance of these filters and their components. This report summarizes characterizations of ash and char samples from pressurized fluidized-bed combustion and gasification facilities. Efforts are under way to develop a method for preserving fragile filter cakes formed on ceramic filter elements. The HGCU data base was formatted for Microsoft Access 97 ® . Plans for the remainder of the project include characterization of additional samples collected during site visits to the Department of Energy / Southern Company Services Power Systems Development Facility and completion and delivery of the HGCU data base.

  9. PARTICULATE HOT GAS STREAM CLEANUP TECHNICAL ISSUES

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-05-05

    This is the fourth annual report describing the activities performed under Task 1 of Contract No. DE-AC21-94MC31160. The analyses of hot gas stream cleanup (HGCU) ashes and descriptions of filter performance studied under this contract are designed to address problems with filter operation that are apparently linked to characteristics of the collected ash. This work is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters and to relate these ash properties to the operation and performance of these filters and their components. This report summarizes characterizations of ash and char samples from pressurized fluidized-bed combustion and gasification facilities. Efforts are under way to develop a method for preserving fragile filter cakes formed on ceramic filter elements. The HGCU data base was formatted for Microsoft Access 97{reg_sign}. Plans for the remainder of the project include characterization of additional samples collected during site visits to the Department of Energy/Southern Company Services Power Systems Development Facility and completion and delivery of the HGCU data base.

  10. [PFBC Hot Gas Cleanup Test Program

    Energy Technology Data Exchange (ETDEWEB)

    1992-10-01

    Four hundred and fifty four clay bonded silicon carbide Schumacher Dia Schumalith candle filters were purchased for installation in the Westinghouse Advanced Particle Filtration (APF) system at the American Electric Power (AEP) plant in Brilliant, Ohio. A surveillance effort has been identified which will monitor candle filter performance and life during hot gas cleaning in AEP's pressurized fluidized-bed combustion system. A description of the candle surveillance program, strategy for candle filter location selection, as well as candle filter post-test characterization is provided in this memo. The period of effort for candle filter surveillance monitoring is planned through March 1994.

  11. Particulate hot gas stream cleanup technical issues

    Energy Technology Data Exchange (ETDEWEB)

    Pontius, D.H.; Snyder, T.R.

    1999-09-30

    The analyses of hot gas stream cleanup particulate samples and descriptions of filter performance studied under this contract were designed to address problems with filter operation that have been linked to characteristics of the collected particulate matter. One objective of this work was to generate an interactive, computerized data bank of the key physical and chemical characteristics of ash and char collected from operating advanced particle filters and to relate these characteristics to the operation and performance of these filters. The interactive data bank summarizes analyses of over 160 ash and char samples from fifteen pressurized fluidized-bed combustion and gasification facilities utilizing high-temperature, high pressure barrier filters.

  12. Hot-gas filtration for pressurized fluidized-bed combustion

    Energy Technology Data Exchange (ETDEWEB)

    Chang, R.; Kuby, W.

    1984-03-01

    This topical report discusses the status of the work, conducted under EPRI contract 1336-4, on the evaluation and development of ceramic filter hot gas cleanup technology for pressurized fluidized bed combustion. This topical report represents the status of the work through September 1983. The goal of the effort is to achieve 6000 h of operation on a 13-filter durability test rig. The work includes two parallel tasks. The first is construction of a durability test facility, operation of the facility with an initial candidate filter media installed, and assessment of results. The second task includes a literature survey to identify state-of-the-art ceramic fibers suitable for high-temperature gas filtration applications and filter testing in a single-filter test facility to assess the performance of promising new filter media. The best candidate will be chosen for further evaluation in the durability facility.

  13. METC CFD simulations of hot gas filtration

    Energy Technology Data Exchange (ETDEWEB)

    O`Brien, T.J.

    1995-06-01

    Computational Fluid Dynamic (CFD) simulations of the fluid/particle flow in several hot gas filtration vessels will be presented. These simulations have been useful in designing filtration vessels and in diagnosing problems with filter operation. The simulations were performed using the commercial code FLUENT and the METC-developed code MFIX. Simulations of the initial configuration of the Karhula facility indicated that the dirty gas flow over the filter assemblage was very non-uniform. The force of the dirty gas inlet flow was inducing a large circulation pattern that caused flow around the candles to be in opposite directions on opposite sides of the vessel. By introducing a system of baffles, a more uniform flow pattern was developed. This modification may have contributed to the success of the project. Several simulations of configurations proposed by Industrial Filter and Pump were performed, varying the position of the inlet. A detailed resolution of the geometry of the candles allowed determination of the flow between the individual candles. Recent simulations in support of the METC/CeraMem Cooperative Research and Development Agreement have analyzed the flow in the vessel during the cleaning back-pulse. Visualization of experiments at the CeraMem cold-flow facility provided confidence in the use of CFD. Extensive simulations were then performed to assist in the design of the hot test facility being built by Ahlstrom/Pyropower. These tests are intended to demonstrate the CeraMem technology.

  14. Particulate hot gas stream cleanup technical issues

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-01

    This is the thirteenth quarterly report describing the activities performed under Contract No. DE-AC21-94MC31160. The analyses of Hot Gas Stream Cleanup (HGCU) ashes and descriptions of filter performance studied under this contract are designed to address problems with filter operation that are apparently linked to characteristics of the collected ash. Task 1 is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters (APFS) and to relate these ash properties to the operation and performance of these filters and their components. APF operations have also been limited by the strength and durability of the ceramic materials that have served as barrier filters for the capture of entrained HGCU ashes. Task 2 concerns testing and failure analyses of ceramic filter elements currently used in operating APFs and the characterization and evaluation of new ceramic materials. Task I research activities during the past quarter included characterizations of additional ash samples from Pressurized Fluidized-Bed Combustion (PFBC) facilities to the HGCU data base. Task I plans for the next quarter include characterization of samples collected during a site visit on January 20 to the Department of Energy / Southern Company Services Power Systems Development Facility (PSDF). Further work on the HGCU data base is also planned. Task 2 work during the past quarter included creep testing of a Coors P- I OOA- I specimen machined from Candle FC- 007 after 1166 hours in-service at the Karhula Pressurized Circulating Fluid Bed (PCFB) facility. Samples are currently in preparation for microstructural evaluations of Coors P-IOOA-I.Sixteen cordierite rings manufactured by Specific Surfaces were received for testing. Three of the specimens were exposed to the PFBC environment at the PSDF. These specimens are currently being machined for testing.

  15. Particulate Hot Gas Stream Cleanup Technical Issues

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    1998-08-31

    This is the fifteenth quarterly report describing the activities performed under Contract No. DE-AC21-94MC31160. The analyses of Hot Gas Stream Cleanup (HGCU) ashes and descriptions of filter performance studied under this contract are designed to address problems with filter operation that are apparently linked to characteristics of the collected ash. Task 1 is designed to generate a data bank of the key characteristics of ashes collected from operating advanced particle filters (APFs) and to relate these ash properties to the operation and performance of these filters and their components. APF operations have also been limited by the strength and durability of the ceramic materials that have served as barrier filters for the capture of entrained HGCU ashes. Task 2 concerns testing and failure analyses of ceramic filter elements currently used in operating APFs and the characterization and evaluation of new ceramic materials. Task 1 research activities during the past quarter included characterizations of samples collected during a site visit on May 18 to the Department of Energy / Southern Company Services Power Systems Development Facility (PSDF) and a particulate sample collected in the Westinghouse filter at Sierra Pacific Power Company's Piñon Pine Power Project. Analysis of this Piñon Pine sample is ongoing: however, this report contains the results of analyses completed to date. Significant accomplishments were achieved on the HGCU data bank during this reporting quarter. The data bank was prepared for presentation at the Advanced Coal-Based Power and Environmental Systems 98 Conference scheduled for July, 1998. Task 2 work during the past quarter consisted of testing two Dupont PRD-66C candle filters, one McDermott ceramic composite candle filter, one Blasch 4-270 candle filter, and one Specific Surface cordierite candle filter. Tensile and thermal expansion testing is complete and the rest of the testing is in progress. Also, some 20-inch long

  16. Particulate Hot Gas Stream Cleanup Technical Issues

    Energy Technology Data Exchange (ETDEWEB)

    Potius, D.; Snyder, T.

    1997-07-01

    The characteristics of entrained particles generated by advanced coal conversion technologies and the harsh flue gas environments from which these particles must be removed challenge current ceramic barrier filtration systems. Measurements have shown that the size distribution, morphology, and chemical composition of particles generated by pressurized fluidized-bed combustion (PFBC) and gasification processes differ significantly from the corresponding characteristics of conventional pulverized-coal ash particles. The entrained particulate matter from these advanced conversion technologies often comprise fine size distributions, irregular particle morphologies, high specific surface areas, and significant proportions of added sorbent material. These characteristics can create high ash cohesivity and high pressure losses through the filter cakes. In addition, the distributions of chemical constituents among the collected particles provide local, highly concentrated chemical species that promote reactions between adjacent particles that ultimately cause strong, nodular deposits to form in the filter vessel. These deposits can lead directly to bridging and filter element failure. This project is designed to address aspects of filter operation that are apparently linked to the characteristics of the collected ash or the performance of the ceramic filter elements. The activities conducted under Task 1, Assessment of Ash Characteristics, are discussed in this paper. Activities conducted under Task 2, Testing and Failure Analysis of Ceramic Filters, are discussed in a separate paper included in the proceedings of the Advanced Coal-Based Power and Environmental Systems `97 Conference. The specific objectives of Task I include the generation of a data base of the key characteristics of Hot Gas Stream Cleanup (HGCU) ashes collected from operating advanced particle filters (APFS) and the identification of relationships between HGCU ash properties and the operation and

  17. Particulate hot gas stream cleanup technical issues

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-01

    This is the eleventh in a series of quarterly reports describing the activities performed under Contract No. DE-AC21-94MC31160. Analyses of Hot Gas Stream Cleanup (HGCU) ashes and descriptions of filter performance address aspects of filter operation that are apparently linked to the characteristics of the collected ash or the performance of the ceramic bed filter elements. Task 1 is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters (APFS) and to relate these ash properties to the operation and performance of these filters. Task 2 concerns testing and failure analysis of ceramic filter elements. Under Task 1 during the past quarter, analyses were completed on samples obtained during a site visit to the Power Systems Development Facility (PSDF). Analyses are in progress on ash samples from the Advanced Particulate Filter (APF) at the Pressurized Fluidized-Bed Combustor (PFBC) that was in operation at Tidd and ash samples from the Pressurized Circulating Fluid Bed (PCFB) system located at Karhula, Finland. An additional analysis was performed on a particulate sample from the Transport Reactor Demonstration Unit (TRDU) located at the University of North Dakota Energy and Environmental Research Center. A manuscript and poster were prepared for presentation at the Advanced Coal-Based Power and Environmental Systems `97 Conference scheduled for July 22 - 24, 1997. A summary of recent project work covering the mechanisms responsible for ash deposit consolidation and ash bridging in APF`s collecting PFB ash was prepared and presented at FETC-MGN in early July. The material presented at that meeting is included in the manuscript prepared for the Contractor`s Conference and also in this report. Task 2 work during the past quarter included mechanical testing and microstructural examination of Schumacher FT20 and Pall 326 as- manufactured, after 540 hr in service at Karhula, and after 1166 hr in service at

  18. PARTICULATE HOT GAS STREAM CLEANUP TECHNICAL ISSUES

    Energy Technology Data Exchange (ETDEWEB)

    D.H. Pontius

    1999-08-30

    This quarterly report describes technical activities performed under Contract No. DE-AC21-94MC31160. The analyses of hot gas stream cleanup (HGCU) ashes and descriptions of filter performance studied under Task 1 of this contract are designed to address problems with filter operation that are apparently linked to characteristics of the collected ash. This report reviews the status of the HGCU data bank of ash and char characteristics, including the interactive querying of measured particulate properties. Task 1 plans for the remainder of the project include completion and delivery of the HGCU data bank, and issuance of a comprehensive final report on activities conducted under Task 1. Task 2 of this project concerns the testing and failure analyses of new and used filter elements and filter materials. Task 2 work during the past quarter included preliminary testing of two materials. One material tested was the soft candle filter manufactured by CGC and supplied by ABB. The other material was N610/mullite manufactured by Albany International (AIT).

  19. PARTICULATE HOT GAS STREAM CLEANUP TECHNICAL ISSUES

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-05-01

    This quarterly report describes technical activities performed under Contract No. DE-AC21-94MC31160. The analyses of hot gas stream cleanup (HGCU) ashes and descriptions of filter performance studied under Task 1 of this contract are designed to address problems with filter operation that are apparently linked to characteristics of the collected ash. This report includes summaries of analyses performed on particulate samples from Sierra Pacific Power Company's Pinon Pine Power Project. This report also reviews the status of the HGCU data bank of ash and char characteristics, and plans for enhancing the data bank with interactive querying of measured particulate properties. Task 1 plans for the remainder of the project include completion and delivery of the HGCU data bank. Task 2 of this project concerns the testing and failure analyses of new and used filter elements and filter materials. Task 2 work during the past quarter included preliminary testing of two materials. One material tested was the soft candle filter manufactured by CGC and supplied by ABB. The other material was N610/mullite manufactured by Albany International (AIT).

  20. Development of regenerable copper-based sorbents for hot gas cleanup: Final technical report, September 1, 1995--August 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Abbasian, J.; Slimane, R.B.; Wangerow, J.R.

    1997-05-01

    The overall objective of this study was to determine the effectiveness of the copper-chromite sorbent (developed in previous ICCI-funded projects) for longer duration application under optimum conditions in the temperature range of 550{degrees}-650{degrees}C to minimize sorbent reduction and degradation during the cyclic process. Three (3) formulations of attrition resistant granules of the copper chromite sorbent (i.e., CuCr-10, CuCr-21, and CuCr-29) as well as one (1) copper chromite sorbent in pellet form (i.e., CuCr-36) were selected for cyclic desulfurization tests. The desulfurization and regeneration capabilities of the selected formulations as well as the effects of operating parameters were determined, to identify the {open_quotes}best{close_quotes} sorbent formulation and the optimum operating conditions. The durability of the {open_quotes}best{close_quotes} sorbent formulation was determined in {open_quotes}long-term{close_quotes} multicycle tests conducted at the optimum operating conditions. The attrition resistance of the selected formulations were determined and compared with those of other sorbents, including a limestone, a dolomite, and a commercial zinc titanate sorbent. The results obtained in this study indicate that, the CuCr-29 sorbent has excellent attrition resistance and desulfurization performance, which are far superior to the commercial zinc titanate sorbents. The optimum desulfurization temperature in terms of sorbent efficiency and utilization appears to be about 600{degrees}C. Sorbent regeneration at 750{degrees}C ensured complete conversion of the copper sulfide to oxide without sulfate formation or reactivity deterioration in subsequent cycles.

  1. Regenerative particulate filter development

    Science.gov (United States)

    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.

  2. An integrated modular hot gas conditioning technology

    Energy Technology Data Exchange (ETDEWEB)

    Abatzoglou, N.; Bangala, D.; Chornet, E. [Kemestrie Inc., Sherbrooke, Quebec (Canada)

    1999-07-01

    Hot gas conditioning is considered the most scientific and technological challenge on the road towards commercialization of large biomass and waste gasification units. The modular hot gas conditioning system presented in this paper is designed to be integrated into any gasification unit regardless of feedstock type and operation pressure. It comprises a mobile granular bed filtration system and an in-series multi-tubular fixed-bed downdraft steam catalytic reformer. In this work we discuss the concept, the design, the methodology and our results. (author)

  3. Particulate hot gas stream cleanup technical issues. Quarterly report, January 1--March 31, 1998

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-08-01

    The analyses of Hot Gas Stream Cleanup (HGCU) ashes and descriptions of filter performance studied under this contract are designed to address problems with filter operation that are apparently linked to characteristics of the collected ash. Task 1 is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters (APFs) and to relate these ash properties to the operation and performance of these filters and their components. APF operations have also been limited by the strength and durability of the ceramic materials that have served as barrier filters for the capture of entrained HGCU ashes. Task 2 concerns testing and failure analyses of ceramic filter elements currently used in operating APFs and the characterization and evaluation of new ceramic materials. Task 1 research activities during the past quarter included characterizations of samples collected during a site visit on January 20 to the Department of Energy/Southern Company Services Power Systems Development Facility (PSDF). Comparisons were made between laboratory analyses of these PSDF ashes and field data obtained from facility operation. In addition, selected laboratory techniques were reviewed to assess their reproducibility and the influence of non-ideal effects and differences between laboratory and filter conditions on the quantities measured. Further work on the HGCU data base is planned for the next quarter. Two Dupont PRD-66 candle filters, one McDermott candle filter, one Blasch candle filter, and one Specific Surfaces candle filter were received at SRI for testing. A test plan and cutting plan for these candles was developed. Acquisition of two of the Dupont PRD-66 candle filters will allow candle-to-candle variability to be examined.

  4. DEVELOPMENT OF AN ADHESIVE CANDLE FILTER SAFEGUARD DEVICE

    Energy Technology Data Exchange (ETDEWEB)

    John P. Hurley; Ann K. Henderson; Jan W. Nowok; Michael L. Swanson

    2002-01-01

    In order to reach the highest possible efficiencies in a coal-fired turbine-based power system, the turbine should be directly fired with the products of coal conversion. Two main types of systems employ these turbines: those based on pressurized fluidized-bed combustors and those based on integrated gasification combined cycles. In both systems, suspended particulates must be cleaned from the gas stream before it enters the turbine so as to prevent fouling and erosion of the turbine blades. To produce the cleanest gas, barrier filters are being developed and are in use in several facilities. Barrier filters are composed of porous, high-temperature materials that allow the hot gas to pass but collect the particulates on the surface. The three main configurations of the barrier filters are candle, cross-flow, and tube filters. Both candle and tube filters have been tested extensively. They are composed of coarsely porous ceramic that serves as a structural support, overlain with a thin, microporous ceramic layer on the dirty gas side that serves as the primary filter surface. They are highly efficient at removing particulate matter from the gas stream and, because of their ceramic construction, are resistant to gas and ash corrosion. However, ceramics are brittle and individual elements can fail, allowing particulates to pass through the hole left by the filter element and erode the turbine. Preventing all failure of individual ceramic filter elements is not possible at the present state of development of the technology. Therefore, safeguard devices (SGDs) must be employed to prevent the particulates streaming through occasional broken filters from reaching the turbine. However, the SGD must allow for the free passage of gas when it is not activated. Upon breaking of a filter, the SGD must either mechanically close or quickly plug with filter dust to prevent additional dust from reaching the turbine. Production of a dependable rapidly closing autonomous mechanical

  5. Limits of search filter development.

    Science.gov (United States)

    Wilczynski, Nancy L; Lokker, Cynthia; McKibbon, Kathleen Ann; Hobson, Nicholas; Haynes, R Brian

    2016-01-01

    The research attempted to develop search filters for biomedical literature databases that improve retrieval of studies of clinical relevance for the nursing and rehabilitation professions. Diagnostic testing framework compared machine-culled and practitioner-nominated search terms with a hand-tagged clinical literature database. We were unable to: (1) develop filters for nursing, likely because of the overlapping and expanding scope of practice for nurses in comparison with medical professionals, or (2) develop filters for rehabilitation, because of its broad scope and the profession's multifaceted understanding of "health and ability." We found limitations on search filter development for these health professions: nursing and rehabilitation.

  6. Hot gas path component having near wall cooling features

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, Carlos Miguel; Kottilingam, Srikanth Chandrudu; Lacy, Benjamin Paul

    2017-11-28

    A method for providing micro-channels in a hot gas path component includes forming a first micro-channel in an exterior surface of a substrate of the hot gas path component. A second micro-channel is formed in the exterior surface of the hot gas path component such that it is separated from the first micro-channel by a surface gap having a first width. The method also includes disposing a braze sheet onto the exterior surface of the hot gas path component such that the braze sheet covers at least of portion of the first and second micro-channels, and heating the braze sheet to bond it to at least a portion of the exterior surface of the hot gas path component.

  7. [PFBC Hot Gas Cleanup Test Program]. Third Quarterly technical progress report, July--September 1992, CY 1992

    Energy Technology Data Exchange (ETDEWEB)

    1992-10-01

    Four hundred and fifty four clay bonded silicon carbide Schumacher Dia Schumalith candle filters were purchased for installation in the Westinghouse Advanced Particle Filtration (APF) system at the American Electric Power (AEP) plant in Brilliant, Ohio. A surveillance effort has been identified which will monitor candle filter performance and life during hot gas cleaning in AEP`s pressurized fluidized-bed combustion system. A description of the candle surveillance program, strategy for candle filter location selection, as well as candle filter post-test characterization is provided in this memo. The period of effort for candle filter surveillance monitoring is planned through March 1994.

  8. Hot particulate removal and desulfurization results from the METC integrated gasification and hot gas cleanup facility

    Energy Technology Data Exchange (ETDEWEB)

    Rockey, J.M.

    1995-06-01

    The Morgantown Energy Technology Center (METC) is conducting experimental testing using a 10-inch diameter fluid-bed gasifier (FBG) and modular hot gas cleanup rig (MGCR) to develop advanced methods for removing contaminants in hot coal gasifier gas streams for commercial development of integrated gasification combined-cycle (IGCC) power systems. The program focus is on hot gas particulate removal and desulfurization technologies that match the temperatures and pressures of the gasifier, cleanup system, and power generator. The purpose of this poster is to present the program objectives and results of the work conducted in cooperation with industrial users and vendors to meet the vision for IGCC of reducing the capital cost per kilowatt to $1050 and increasing the plant efficiency to 52% by the year 2010.

  9. Hot gas cleanup test facility for gasification and pressurized combustion. Quarterly technical progress report, July 1--September 30, 1992

    Energy Technology Data Exchange (ETDEWEB)

    1992-12-31

    The objective of this project is to evaluate hot gas particle control technologies using coal-derived gas streams. This will entail the design, construction, installation, and use of a flexible test facility which can operate under realistic gasification and combustion conditions. The major particulate control device issues to be addressed include the integration of the particulate control devices into coal utilization systems, on-line cleaning techniques, chemical and thermal degradation of components, fatigue or structural failures, blinding, collection efficiency as a function of particle size, and scale-up of particulate control systems to commercial size. The conceptual design of the facility was extended to include a within scope, phased expansion of the existing Hot Gas Cleanup Test Facility Cooperative Agreement to also address systems integration issues of hot particulate removal in advanced coal-based power generation systems. This expansion included the consideration of the following modules at the test facility in addition to the existing Transport Reactor gas source and Hot Gas Cleanup Units: Carbonizer/Pressurized Circulating Fluidized Bed Gas Source; hot Gas Cleanup Units to mate to all gas streams; and Combustion Gas Turbine. Fuel Cell and associated gas treatment. This expansion to the Hot Gas Cleanup Test Facility is herein referred to as the Power Systems Development Facility (PSDF).

  10. Particulate hot gas stream cleanup technical issues. Quarterly report, April 1 - June 30, 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    This is the seventh in a series of quarterly reports describing the activities performed for this project. Our analyses of Hot Gas Stream Cleanup (HGCU) ashes and descriptions of filter performance address aspects of filter operation that are apparently linked to the characteristics of the collected ash or the performance of the ceramic barrier filter elements. Task 1 is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters (APFs) and to relate these ash properties to the operation and performance of these filters. Task 2 concerns testing and failure analysis of ceramic filter elements. Under Task 1 during the past quarter, we received and analyzed a hopper ash sample from the Transport Reactor Demonstration Unit (TRDU) located at the University of North Dakota`s Energy and Environmental Research Center (UNDEERC). We also received six ash samples from the Ahlstrom 10 MWt Pressurized Fluidized Circulating Fluid Bed (PCFB) facility located at Karhula, Finland. We selected one of the filter cake ashes from this batch of samples for detailed analyses. We continued our work on the HGCU data base we are constructing in Microsoft Access{reg_sign}. We have been entering a variety of information into the data base, including numerical values, short or long text entries, and photographs. Task 2 efforts during the past quarter focused on hoop tensile testing of Schumacher FT20 and Refractron candle filter elements removed from the Karhula APF after {approximately}540 hours of service.

  11. Investigation of austenitic alloys for advanced heat recovery and hot gas cleanup systems

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W.; Ren, W.

    1996-06-01

    The objective of the research is to provide databases and design criteria to assist in the selection of optimum alloys for construction of components needed to contain process streams in advanced heat recovery and hot-gas cleanup systems. Typical components include: steam line piping and superheater tubing for low emission boilers (600 to 700{degrees}C), heat exchanger tubing for advanced steam cycles and topping cycle systems (650 to 800{degrees}C), foil materials for recuperators, on advanced turbine systems (700 to 750{degrees}C), and tubesheets for barrier filters, liners for piping, cyclones, and blowback system tubing for hot-gas cleanup systems (850 to 1000{degrees}C). The materials being examined fall into several classes, depending on which of the advanced heat recovery concepts is of concern. These classes include martensitic steels for service to 650{degrees}C, lean stainless steels and modified 25Cr-30Ni steels for service to 700{degrees}C, modified 25Cr-20Ni steels for service to 900{degrees}C, and high Ni-Cr-Fe or Ni-Cr-Co-Fe alloys for service to 1000{degrees}C.

  12. Experimental and Numerical Investigations on Flue Gas Purification during Hot Gas Filtration

    Energy Technology Data Exchange (ETDEWEB)

    Thulfaut, C.; Renz, U.

    2002-09-19

    The aim of the actual investigations is to integrate the catalytic reduction of carbon monoxide and particularly nitric oxides into the hot gas filtration process with ceramic filter elements of fluidized bed combustors which mainly represent an important N2O-source. According to Klein (Klein 1994) worldwide approx. 260 coal-fired power plants with fluidized bed combustors in the power range > 50 MWel existed in 1994, to which approx. 1% of the global coal dissipation corresponds. These emitted dinitrogen oxide with 70 kt/a, however, 20% of the entire N2O amounts from stationary firing plants. After Kleins calculations an increase of coal-fired fluidized bed combustors only by 10% triples the N2O emission.

  13. 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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  14. Application of CFCC technology to hot gas filtration applications

    Energy Technology Data Exchange (ETDEWEB)

    Richlen, S.

    1995-06-01

    Discussion will feature high temperature filter development under the DOE`s Office of Industrial Technologies Continuous Fiber Ceramic Composite (CFCC) Program. Within the CFCC Program there are four industry projects and a national laboratory technology support project. Atlantic Research, Babcock & Wilcox, DuPont Lanxide Composites, and Textron are developing processing methods to produce CFCC Components with various types of matrices and composites, along with the manufacturing methods to produce industrial components, including high temperature gas filters. The Oak Ridge National Laboratory is leading a National Laboratory/University effort to increase knowledge of such generic and supportive technology areas as environmental degradation, measurement of mechanical properties, long-term performance, thermal shock and thermal cycling, creep and fatigue, and non-destructive characterization. Tasks include composite design, materials characterization, test methods, and performance-related phenomena, that will support the high temperature filter activities of industry and government.

  15. Particulate hot gas stream cleanup technical issues. Quarterly report, January--March 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-05-21

    To identify which ash characteristics can lead to problems with filtration, the authors have assembled 235 ash samples from eleven facilities involved in METC`s HGCU program. They have analyzed many of these ashes with a variety of laboratory tests. Physical attributes of the particles that they have examined include size distribution, specific surface area, particle morphology, and bulk ash cohesivity and permeability. They have also performed a range of chemical analyses on these ashes, as well as characterizations of agglomerates of ash removed from filter vessels at Tidd and Karhula. They are in the process of assembling the data obtained in these studies into an interactive data base which will help the manufacturers and operators of high-temperature barrier filters tailor their designs and operations to the specific characteristics of the ashes they are collecting. In order to understand the thermal and mechanical behavior of the various types of ceramic materials used in hot gas filtration, they have been performing hoop and axial tensile tests, thermal expansion, compression, and creep evaluations of these materials at temperatures up to 1,800 F. Nondestructive testing methods they perform on filter specimens include density and ultrasonic velocity. To date they have evaluated various characteristics of Dupont/Lanxide PRD-66, Dupont composite, 3M composite, IF and P Fibrosics, Refractron, Schumacher, and Blasch alumina mullite materials.

  16. Hot gas filtration: Investigations to remove gaseous pollutant components out of flue gas during hot gas filtration. Final report; HGR: Untersuchung zur Minimierung von gasfoermigen Schadstoffen aus Rauchgasen bei der Heissgasfiltration. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Christ, A.; Gross, R.; Renz, U.

    1998-07-01

    Power plants with gas and steam turbines in pressurized fluidized bed or pressurized gasification processes enable power generation of coal with high efficiency and little emissions. To run these plants the cleaning of the flue gas is necessary before entering the turbines under the conditions of high temperature and pressure. Ceramic filter elements are the most probable method for hot gas cleaning. A simultaneous reduction of gaseous pollutant components under these conditions could help to make the whole process more efficient. The aim of the project is to integrate the catalytic reduction of carbon monoxide, hydrocarbons and nitric oxides into the hot gas filtration with ceramic filter elements as a one step mecanism. The project is focused on: - the catalytic behaviour of ferruginous ashes of brown coal, - the effectiveness of calcinated aluminates as a catalyst to remove uncombusted hydrocarbons in a hot gas filtration unit, - numerical simulation of the combined removal of particles and gaseous pollutant components out of the flue gas. (orig.) [Deutsch] Gas- und Dampfturbinen-Kraftwerke mit Druckwirbelschicht- oder mit Druckvergasungsverfahren ermoeglichen die Verstromung von Kohle mit hohem Wirkungsgrad und niedrigen Emissionen. Eine Voraussetzung fuer den Betrieb dieser Anlagen ist die Entstaubung der Rauchgase bei hohen Temperaturen und Druecken. Abreinigungsfilter mit keramischen Elementen werden dazu eingesetzt. Eine Reduzierung gasfoermiger Schadstoffe unter den gleichen Bedingungen koennte die Rauchgaswaesche ersetzen. Ziel des Gesamtvorhabens ist es, die Integration von Heissgasfiltration und katalytischem Abbau der Schadstoffe Kohlenmonoxid, Kohlenwasserstoffe und Stickoxide in einem Verfahrensschritt zu untersuchen. Die Arbeitsschwerpunkte dieses Teilvorhabens betreffen - die katalytische Wirkung eisenhaltiger Braunkohlenaschen, - die Wirksamkeit des Calciumaluminats als Katalysator des Abbaus unverbrannter Kohlenwasserstoffe im Heissgasfilter

  17. Advanced turbine design for coal-fueled engines. Phase 1, Erosion of turbine hot gas path blading: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, J.H.; Johnson, B.V.

    1993-04-01

    The investigators conclude that: (1) Turbine erosion resistance was shown to be improved by a factor of 5 by varying the turbine design. Increasing the number of stages and increasing the mean radius reduces the peak predicted erosion rates for 2-D flows on the blade airfoil from values which are 6 times those of the vane to values of erosion which are comparable to those of the vane airfoils. (2) Turbine erosion was a strong function of airfoil shape depending on particle diameter. Different airfoil shapes for the same turbine operating condition resulted in a factor of 7 change in airfoil erosion for the smallest particles studied (5 micron). (3) Predicted erosion for the various turbines analyzed was a strong function of particle diameter and weaker function of particle density. (4) Three dimensional secondary flows were shown to cause increases in peak and average erosion on the vane and blade airfoils. Additionally, the interblade secondary flows and stationary outer case caused unique erosion patterns which were not obtainable with 2-D analyses. (5) Analysis of the results indicate that hot gas cleanup systems are necessary to achieve acceptable turbine life in direct-fired, coal-fueled systems. In addition, serious consequences arise when hot gas filter systems fail for even short time periods. For a complete failure of the filter system, a 0.030 in. thick corrosion-resistant protective coating on a turbine blade would be eroded at some locations within eight minutes.

  18. Hot gas cleanup test facility for gasification and pressurized combustion. Quarterly technical progress report, January 1--March 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    1992-12-01

    This quarterly technical progress report summarizes work completed during the Sixth Quarter of the First Budget Period, January 1 through March 31, 1992, under the Department of Energy (DOE) Cooperative Agreement No. DE-FC21-90MC25140 entitled ``Hot Gas Cleanup Test Facility for Gasification and Pressurized Combustion.`` The objective of this project is to evaluate hot gas particle control technologies using coal-derived gas streams. The major emphasis during this reporting period was expanding the test facility to address system integration issues of hot particulate removal in advanced power generation systems. The conceptual design of the facility was extended to include additional modules for the expansion of the test facility, which is referred to as the Power Systems Development Facility (PSOF). A letter agreement was negotiated between Southern Company Services (SCS) and Foster Wheeler (FW) for the conceptual design of the Advanced Pressurized Fluid-Bed Combustion (APFBC)/Topping Combustor/Gas Turbine System to be added to the facility. The expanded conceptual design also included modifications to the existing conceptual design for the Hot Gas Cleanup Test Facility (HGCTF), facility layout and balance of plant design for the PSOF. Southern Research Institute (SRI) began investigating the sampling requirements for the expanded facility and assisted SCS in contacting Particulate Control Device (PCD) vendors for additional information. SCS also contacted the Electric Power Research Institute (EPRI) and two molten carbonate fuel cell vendors for input on the fuel cell module for the PSDF.

  19. Particulate Hot Gas Stream Cleanup Technical Issues: Quarterly report, July 1-September 30, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Pontius, D.H.

    1996-12-09

    This is the eighth in a series of quarterly reports describing the activities performed under Contract No. DE-AC21-94MC31160. Analyses of Hot Gas Stream Cleanup (HGCU) ashes and descriptions of filter performance address aspects of filter operation that are apparently linked to the characteristics of the collected ash or the performance of the ceramic barrier filter elements. Task 1 is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters (APFS) and to relate these ash properties to the operation and performance of these filters. Task 2 concerns testing and failure analysis of ceramic filter elements. Under Task I during the past quarter, additional analyses were performed on ashes from the Ahlstrom 10 MWt Pressurized Fluidized Circulating Fluid Bed (PCFB) facility located at Karhula, Finland. Work continued on the HGCU data base being constructed in Microsoft Access. A variety of information has been entered into the data base, including numerical values, short or long text entries, and photographs. Detailed design of a bench top device for high temperature measurement of ash permeability has also begun. In addition to these activities, a paper was prepared and a poster was presented summarizing recent work performed under this contract at the 1996 DOE/METC Contractor`s Conference. A presentation was also given corresponding to the manuscript entitled Particle Characteristics and High-Temperature Filtration that was prepared for publication in the Proceedings of the Thirteenth Annual International Pittsburgh Coal Conference held this September in Pittsburgh, PA. Arrangements have been made to be present at the DOE/METC Modular Gas Cleanup Rig (MGCR) at the conclusion of the next run of the DOE/METC air blown Fluid Bed Gasifier (FBG). This visit will include on-site sampling to collect and characterize the filter cakes collected during FGB operation. Task 2 efforts during the past quarter focused on

  20. Investigation of austenitic alloys for advanced heat recovery and hot gas cleanup systems

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W.; Ren, W. [Oak Ridge National Lab., TN (United States)

    1995-08-01

    Alloys for design and construction of structural components needed to contain process streams and provide internal structures in advanced heat recovery and hot gas cleanup systems were examined. Emphasis was placed on high-strength, corrosion-resistant alloys for service at temperatures above 1000 {degrees}F (540{degrees}C). Data were collected that related to fabrication, joining, corrosion protection, and failure criteria. Alloys systems include modified type 310 and 20Cr-25Ni-Nb steels and sulfidation-resistance alloys HR120 and HR160. Types of testing include creep, stress-rupture, creep crack growth, fatigue, and post-exposure short-time tensile. Because of the interest in relatively inexpensive alloys for high temperature service, a modified type 310 stainless steel was developed with a target strength of twice that for standard type 310 stainless steel.

  1. 3-D woven, mullite matrix, composite filter

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-12-01

    Westinghouse, with Techniweave as a major subcontractor, is conducting a three-phase program aimed at providing advanced candle filters for a 1996 pilot scale demonstration in one of the two hot gas filter systems at Southern Company Service`s Wilsonville PSD Facility. The Base Program (Phases I and II) objective is to develop and demonstrate the suitability of the Westinghouse/Techniweave next generation composite candle filter for use in Pressurized Fluidized Bed Combustion (PFBC) and/or Integrated Gasification Combined Cycle (IGCC) power generation systems. The Optional Task (Phase M, Task 5) objective is to fabricate, inspect and ship to Wilsonville Hot gas particulate filters are key components for the successful commercializaion of advanced coal-based power-generation systems such as Pressurized Fluidized-bed Combustion (PFBC), including second-generation PFBC, and Integrated Gasification Combined Cycles (IGCC). Current generation monolithic ceramic filters are subject to catastrophic failure because they have very low resistance to crack propagation. To overcome this problem, a damage-tolerant ceramic filter element is needed.

  2. Kinetic behaviour of iron oxide sorbent in hot gas desulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Y.G. Pan; J.F. Perales; E. Velo; L. Puigjaner [Universitat Politecnica de Catalunya, Barcelona (Spain). Department of Chemical Engineering

    2005-06-01

    Although a number of reports on sorbents containing ZnO for H{sub 2}S removal from coal-derived gases can be found in the literature, it is shown in our study that a special sorbent containing Fe{sub 2}O{sub 3}{center_dot}FeO (SFO) with minor promoters (Al{sub 2}O{sub 3}, K{sub 2}O, and CaO) as the main active species is more attractive for both sulfidation and regeneration stages, also under economic considerations. This paper presents the kinetic behaviour of SFO in a hot gas desulfurization process using a thermogravimetric analysis under isothermal condition in the operating range between 500 and 800{sup o}C. The gas stream was N{sub 2} with a 2% wt of H{sub 2}S. Experiences carried out on sorbent sulfidation with SFO (particle sizes in the range of 0.042-0.12 mm) indicate that the sorbent sulfidation capacity sharply increases with temperature in the range of 500-600{sup o}C. It is also shown that the sample weight reaches its maximum absorption capacity, near saturation, at 600{sup o}C so that it makes no sense to increase the sulfidation temperature from this point. To make a comparison between SFO and a zinc titanate based sorbent, a set of sulfidation tests was carried out at 600{sup o}C during 7200 s using the same sieve range for both sorbents between 42 and 90 m. Results show that the sulfidation capacity of SFO is 1.9 times higher than that of zinc titanate. 11 refs., 8 figs., 1 tab.

  3. Particulate hot gas stream cleanup technical issues: Task 1.0, Assessment of ash characteristics. Quarterly report, January--March 1995

    Energy Technology Data Exchange (ETDEWEB)

    Pontius, D.H.

    1995-05-01

    Analyses of Hot Gas Stream Cleanup (HGSC) ashes and descriptions of filter performance were made to address the problems with filter operation that are apparently linked to the collected ash. This task is designed to generate data base of the key properties of ashes collected from operating advanced particle filters and to relate these ash proeprties to the operation and performance of these filters. Activities including initial formatting of the data base and entry, modification of the permeability model, and initial design of a high-temperature test device for measuring uncompacted bulk porosity of ashe aggregates (indicator of relative cohesivity of the ash, filter cake porosity/permeability). Chemical analyses of hopper and filter cake ashes from Tidd showed that the consolidation degree could not be accounted for by condensation/adsorption from the flue gas; the mechanism is likely physical rearrangement of the ash particles.

  4. Numerical Investigation of the Transient Behavior of a Hot Gas Duct under Rapid Depressurization

    Directory of Open Access Journals (Sweden)

    JingBao Liu

    2016-01-01

    Full Text Available A hot gas duct is an indispensable component for the nuclear-process heat applications of the Very-High-Temperature Reactor (VHTR, which has to fulfill three requirements: to withstand high temperature, high pressure, and large pressure transient. In this paper, numerical investigation of pressure transient is performed for a hot gas duct under rapid depressurization. System depressurization imposes an imploding pressure differential on the internal structural elements of a hot gas duct, the structural integrity of which is susceptible to being damaged. Pressure differential and its imposed duration, which are two key factors to evaluate the damage severity of a hot gas duct under depressurization, are examined in regard to depressurization rate and insulation packing tightness. It is revealed that depressurization rate is a decisive parameter for controlling the pressure differential and its duration, whereas insulating-packing tightness has little effect on them.

  5. Detection of Hot Gas in Galaxy Groups via the Sunyaev-Zel'dovich Effect

    OpenAIRE

    Moodley, K.; Warne, R.; Goheer, N.; Trac, H.

    2008-01-01

    Motivated by the observed shortfall of baryons in the local universe, we investigate the ability of high resolution cosmic microwave background (CMB) experiments to detect hot gas in the outer regions of nearby group halos. We construct hot gas models with the gas in hydrostatic equilibrium with the dark matter and described by a polytropic equation of state. We also consider models that add entropy to the gas in line with constraints from X-ray observations. We calculate the thermal Sunyaev-...

  6. Flight prototype regenerative particulate filter system development

    Science.gov (United States)

    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.

  7. Chemical hot gas purification for biomass gasification processes; Chemische Heissgasreinigung bei Biomassevergasungsprozessen

    Energy Technology Data Exchange (ETDEWEB)

    Stemmler, Michael

    2010-07-01

    The German government decided to increase the percentage of renewable energy up to 20 % of all energy consumed in 2020. The development of biomass gasification technology is advanced compared to most of the other technologies for producing renewable energy. So the overall efficiency of biomass gasification processes (IGCC) already increased to values above 50 %. Therefore, the production of renewable energy attaches great importance to the thermochemical biomass conversion. The feedstock for biomass gasification covers biomasses such as wood, straw and further energy plants. The detrimental trace elements released during gasification of these biomasses, e.g. KCl, H{sub 2}S and HCl, cause corrosion and harm downstream devices. Therefore, gas cleaning poses an especial challenge. In order to improve the overall efficiency this thesis aims at the development of gas cleaning concepts for the allothermic, water blown gasification at 800 C and 1 bar (Guessing-Process) as well as for the autothermic, water and oxygen blown gasification at 950 C and 18 bar (Vaernamo-Process). Although several mechanisms for KCl- and H{sub 2}S-sorption are already well known, the achievable reduction of the contamination concentration is still unknown. Therefore, calculations on the produced syngas and the chemical hot gas cleaning were done with a thermodynamic process model using SimuSage. The syngas production was included in the calculations because the knowledge of the biomass syngas composition is very limited. The results of these calculations prove the dependence of syngas composition on H{sub 2}/C-ratio and ROC (Relative Oxygen Content). Following the achievable sorption limits were detected via experiments. The KCl containing syngases were analysed by molecular beam mass spectrometry (MBMS). Furthermore, an optimised H{sub 2}S-sorbent was developed because the examined sorbents exceeded the sorption limit of 1 ppmv. The calculated sorption limits were compared to the limits

  8. Novel Backup Filter Device for Candle Filters

    Energy Technology Data Exchange (ETDEWEB)

    Bishop, B.; Goldsmith, R.; Dunham, G.; Henderson, A.

    2002-09-18

    The currently preferred means of particulate removal from process or combustion gas generated by advanced coal-based power production processes is filtration with candle filters. However, candle filters have not shown the requisite reliability to be commercially viable for hot gas clean up for either integrated gasifier combined cycle (IGCC) or pressurized fluid bed combustion (PFBC) processes. Even a single candle failure can lead to unacceptable ash breakthrough, which can result in (a) damage to highly sensitive and expensive downstream equipment, (b) unacceptably low system on-stream factor, and (c) unplanned outages. The U.S. Department of Energy (DOE) has recognized the need to have fail-safe devices installed within or downstream from candle filters. In addition to CeraMem, DOE has contracted with Siemens-Westinghouse, the Energy & Environmental Research Center (EERC) at the University of North Dakota, and the Southern Research Institute (SRI) to develop novel fail-safe devices. Siemens-Westinghouse is evaluating honeycomb-based filter devices on the clean-side of the candle filter that can operate up to 870 C. The EERC is developing a highly porous ceramic disk with a sticky yet temperature-stable coating that will trap dust in the event of filter failure. SRI is developing the Full-Flow Mechanical Safeguard Device that provides a positive seal for the candle filter. Operation of the SRI device is triggered by the higher-than-normal gas flow from a broken candle. The CeraMem approach is similar to that of Siemens-Westinghouse and involves the development of honeycomb-based filters that operate on the clean-side of a candle filter. The overall objective of this project is to fabricate and test silicon carbide-based honeycomb failsafe filters for protection of downstream equipment in advanced coal conversion processes. The fail-safe filter, installed directly downstream of a candle filter, should have the capability for stopping essentially all particulate

  9. Developing metal coated mesh filters for mid-infrared astronomy

    Science.gov (United States)

    Sako, Shigeyuki; Miyata, Takashi; Kamizuka, Takafumi; Nakamura, Tomohiko; Asano, Kentaro; Uchiyama, Mizuho; Onaka, Takashi; Sakon, Itsuki; Wada, Takehiko

    2012-09-01

    A metal mesh filter is appropriate to a band-pass filter for astronomy in the long mid-infrared between 25 and 40 μm, where most of optical materials are opaque. The mesh filter does not require transparent dielectric materials unlike interference filters because the transmission characteristics bare determined by surface plasmon-polariton (SPP) resonances excited on a metal surface with a periodic structure. In this study, we have developed the mesh filters optimized to atmospheric windows at 31.8 and 37.5 μm accessible from the Chajnantor site of 5,640 m altitude. First, mesh filters made of a gold film of 2 μm thickness have been fabricated. Four identical film-type filters are stacked incoherently to suppress leakages at stop-bands. The transmissions of the stacked filters have been measured to be 0.8 at the peaks and below 1 x 10-3 at the stop-bands at 4 K. The ground-based mid-infrared camera MAX38 has been equipped with the stacked filters and successfully obtained diffraction-limited stellar images at the Chajnantor site. The film-type mesh filter does not have sufficient mechanical strength for a larger aperture and for use in space. We have developed mesh filters with higher strength by applying the membrane technology for x-ray optics. The membrane-type mesh filter is made of SiC and coated with a thin gold layer. The optical performance of the mesh filter is independent of internal materials in principle because the SPP resonances are excited only on the metal surface. The fabricated membrane-type mesh filter has been confirmed to provide comparable optical performance to the film-type mesh filter.

  10. Assessment of coal gasification/hot gas cleanup based advanced gas turbine systems

    Energy Technology Data Exchange (ETDEWEB)

    1990-12-01

    The major objectives of the joint SCS/DOE study of air-blown gasification power plants with hot gas cleanup are to: (1) Evaluate various power plant configurations to determine if an air-blown gasification-based power plant with hot gas cleanup can compete against pulverized coal with flue gas desulfurization for baseload expansion at Georgia Power Company's Plant Wansley; (2) determine if air-blown gasification with hot gas cleanup is more cost effective than oxygen-blown IGCC with cold gas cleanup; (3) perform Second-Law/Thermoeconomic Analysis of air-blown IGCC with hot gas cleanup and oxygen-blown IGCC with cold gas cleanup; (4) compare cost, performance, and reliability of IGCC based on industrial gas turbines and ISTIG power island configurations based on aeroderivative gas turbines; (5) compare cost, performance, and reliability of large (400 MW) and small (100 to 200 MW) gasification power plants; and (6) compare cost, performance, and reliability of air-blown gasification power plants using fluidized-bed gasifiers to air-blown IGCC using transport gasification and pressurized combustion.

  11. Integrated operation of a pressurized fixed-bed gasifier, hot gas desulfurization system, and turbine simulator

    Energy Technology Data Exchange (ETDEWEB)

    Bevan, S.; Ayala, R.E.; Feitelberg, A.; Furman, A.

    1995-11-01

    The overall objective of the General Electric Hot Gas Cleanup (HGCU) Program is to develop a commercially viable technology to remove sulfur, particulates, and halogens from a high-temperature fuel gas stream using a moving bed, regenerable mixed metal oxide sorbent based process. The HGCU Program is based on the design and demonstration of the HGCU system in a test facility made up of a pilot-scale fixed bed gasifier, a HGCU system, and a turbine simulator in Schenectady, NY, at the General Electric Research and Development Center. The objectives of the turbine simulator testing are (1) to demonstrate the suitability of fuel gas processed by the HGCU system for use in state-of-the-art gas turbines firing at 2,350 F rotor inlet temperature and (2) to quantify the combustion characteristics and emissions on low-Btu fuel gas. The turbine simulator program also includes the development and operation of experimental combustors based on the rich-quench-lean concept (RQL) to minimize the conversion of ammonia and other fuel-bound nitrogen species to NO{sub x} during combustion. The HGCU system and turbine simulator have been designed to process approximately 8,000 lb/hr of low heating value fuel gas produced by the GE fixed bed gasifier. The HGCU system has utilized several mixed metal oxide sorbents, including zinc ferrite, zinc titanate, and Z-Sorb, with the objective of demonstrating good sulfur removal and mechanical attrition resistance as well as economic cost characteristics. Demonstration of halogen removal and the characterization of alkali and trace metal concentrations in the fuel gas are subordinate objectives of the overall program. This report describes the results of several long-duration pilot tests.

  12. Multidimensional filter banks and wavelets research developments and applications

    CERN Document Server

    Levy, Bernard

    1997-01-01

    Multidimensional Filter Banks and Wavelets: Reserach Developments and Applications brings together in one place important contributions and up-to-date research results in this important area. Multidimensional Filter Banks and Wavelets: Research Developments and Applications serves as an excellent reference, providing insight into some of the most important research issues in the field.

  13. Modelling and experimental validation of the hot-gas defrost process of an air-cooled evaporator

    Energy Technology Data Exchange (ETDEWEB)

    Dopazo, J. Alberto; Fernandez-Seara, Jose; Uhia, Francisco J.; Diz, Ruben [Area de Maquinas y Motores Termicos, E.T.S. de Ingenieros Industriales, University of Vigo, Campus Lagoas-Marcosende No 9, 36310 Vigo, Pontevedra (Spain)

    2010-06-15

    A detailed transient simulation model has been developed to predict and evaluate the performance of the hot-gas defrost process of an air-coil evaporator. In the model, the defrost process is subdivided into six stages: preheating, tube frost melting start, fin frost melting start, air presence, tube-fin water film and dry-heating. In each stage, the control volume is subdivided into systems represented by a single node, which has the representative properties of the system. A finite difference approach was used to solve the model equations. The results include the time required to defrost, the distribution of the energy during defrost process, the instantaneous refrigerant properties and the instantaneous fin and tube temperature distribution. The results are compared with experimental data obtained in a local storage facility under actual operating conditions and also using data available in the literature. The model results substantially agree with the experimental data in both cases. (author)

  14. Particulate hot gas stream cleanup technical issues. Quarterly technical progress report, July 1995--September 1995

    Energy Technology Data Exchange (ETDEWEB)

    Pontius, D.H.

    1995-12-15

    This is the fourth quarterly report describing the activities performed under Contract No. DE-AC21-94MC31160. Task 1 of this contract concerns analyses of HGCU ashes and descriptions of filter performance that are designed to address the problems with filter operation linked to the characteristics of the collected ash. Task 2 of this contract includes characterization of new and used filter elements. Some of the problems observed at the Tidd and Karhula PFBC facilities include excessive filtering pressure drop, the formation of large, tenacious ash deposits within the filter vessel, and bent or broken candle filter elements. These problems have been attributed to ash characteristics, durability of the ceramic filter elements, and specific limitations of the filter design. In addition to these problems related to the characteristics of PFBC ashes, our laboratory characterizations of gasifier and carbonize ashes have shown that these ashes also have characteristics that might negatively affect filtration. Problems with the durability of the filter elements are being addressed by the development and evaluation of elements constructed from alternative ceramic materials.

  15. Particulate hot gas stream cleanup technical issues. Quarterly report, October 1995--December 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    This is the fifth quarterly report describing the activities performed under Contract No. DE-AC21-94MC31160. Task 1 of this contract concerns analyses of HGCU ashes and descriptions of filter performance that are designed to address the problems with filter operation linked to the characteristics of the collected ash. Task 2 of this contract includes characterization of new and used filter elements. Some of the problems observed at the Tidd and Karhula PFBC facilities include excessive filtering pressure drop, the formation of large, tenacious ash deposits within the filter vessel, and bent or broken candle filter elements. These problems have been attributed to ash characteristics, durability of the ceramic filter elements, and specific limitations of the filter design. In addition to these problems related to the characteristics of PFBC ashes, our laboratory characterizations of gasifier and carbonizer ashes have shown that these ashes also have characteristics that might negatively affect filtration. Problems with the durability of the filter elements are being addressed by the development and evaluation of elements constructed from alternative ceramic materials.

  16. Filtered Containment Venting - latest developments in Spain

    Energy Technology Data Exchange (ETDEWEB)

    Zieger, T.

    2015-07-01

    Introduction: The containment of a Nuclear Power Plant (NPP) is the last barrier for the release of radioactive substances to the environment. The “Status Report on Filtered Containment Venting” [1] states the following: In case of a Severe Accident the containment can be pressurized with a pressure exceeding its failure pressure. In order to keep the containment intact de-pressurization should be possible. To protect the environment against contamination with fission products filtration of the released gas is recommended. Filtered containment venting (FCV) is an additional option to protect the containment and the facility while mitigating radioactivity releases to the environment. The Fukushima Daiichi NPP’s accident demonstrated that in the absence of alternatives to reduce the containment pressure build-up due to steam and incondensable gas accumulation during an accident, the venting of the containment becomes an essential accident management measure for the preservation of its structural integrity... (Author)

  17. Hot Gas Cleanup Test Facility for gasification and pressurized combustion. Quarterly report, October--December 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-02-01

    The objective of this project is to evaluate hot gas particle control technologies using coal-derived gas streams. This will entail the design, construction, installation, and use of a flexible test facility which can operate under realistic gasification and combustion conditions. The major particulate control device issues to be addressed include the integration of the particulate control devices into coal utilization systems, on-line cleaning techniques, chemical and thermal degradation of components, fatigue or structural failures, blinding, collection efficiency as a function of particle size, and scale-up of particulate control systems to commercial size. The conceptual design of the facility was extended to include a within scope, phased expansion of the existing Hot Gas Cleanup Test Facility Cooperative Agreement to also address systems integration issues of hot particulate removal in advanced coal-based power generation systems. This expansion included the consideration of the following modules at the test facility in addition to the original Transport Reactor gas source and Hot Gas Cleanup Units: carbonizer/pressurized circulating fluidized bed gas source; hot gas cleanup units to mate to all gas streams; combustion gas turbine; and fuel cell and associated gas treatment. The major emphasis during this reporting period was continuing the detailed design of the facility and integrating the particulate control devices (PCDs) into structural and process designs. Substantial progress in underground construction activities was achieved during the quarter. Delivery and construction of coal handling and process structural steel began during the quarter. Delivery and construction of coal handling and process structural steel began during the quarter. MWK equipment at the grade level and the first tier are being set in the structure.

  18. Development of Test Protocols for International Space Station Particulate Filters

    Science.gov (United States)

    Green, Robert D.; Vijayakumar, R.; Agui, Juan H.

    2014-01-01

    Air quality control on the International Space Station (ISS) is a vital requirement for maintaining a clean environment for the crew and the hardware. This becomes a serious challenge in pressurized space compartments since no outside air ventilation is possible, and a larger particulate load is imposed on the filtration system due to lack of gravitational settling. The ISS Environmental Control and Life Support System (ECLSS) uses a filtration system that has been in use for over 14 years and has proven to meet this challenge. The heart of this system is a traditional High- Efficiency Particulate Air (HEPA) filter configured to interface with the rest of the life support elements and provide effective cabin filtration. Over the years, the service life of these filters has been re-evaluated based on limited post-flight tests of returned filters and risk factors. On earth, a well designed and installed HEPA filter will last for several years, e.g. in industrial and research clean room applications. Test methods for evaluating these filters are being developed on the basis of established test protocols used by the industry and the military. This paper will discuss the test methods adopted and test results on prototypes of the ISS filters. The results will assist in establishing whether the service life can be extended for these filters. Results from unused filters that have been in storage will also be presented to ascertain the shelf life and performance deterioration, if any and determine if the shelf life may be extended.

  19. Combined Particle Filter and Selective Catalytic Reduction Catalyst for Diesel Engines

    DEFF Research Database (Denmark)

    Hvam, Jeanette

    them ideal for multiple applications like high power electronic devices, heating elements, abrasive materials and cutting tools. Porous silicon carbide is suitable for electrode and catalyst support material as well as hot gas filter units or a combination of these. The automotive industry demands new...... for exhaust gas purification. By combining the particulate filtration application with the application as catalyst support for NOx reduction, the low emissions standards can be met. This project was initiated as a result of the need for new and improved filters with characteristics making it suitable...... here. A new and improved filter was developed on the basis of the research results concerning copper as partner additive. In comparison to filters produced with aluminium as sole additive, these new filters exhibit enhanced mechanical stability, enhanced microstructure and controllable surface...

  20. Hot gas path component cooling system having a particle collection chamber

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, Carlos Miguel; Lacy, Benjamin Paul

    2018-02-20

    A cooling system for a hot gas path component includes a substrate having an outer surface and an inner surface. The inner surface defines at least one interior space. A passage is formed in the substrate between the outer surface and the inner surface. An access passage is formed in the substrate and extends from the outer surface to the inner space. The access passage is formed at a first acute angle to the passage and includes a particle collection chamber. The access passage is configured to channel a cooling fluid to the passage. Furthermore, the passage is configured to channel the cooling fluid therethrough to cool the substrate.

  1. Fuel Efficient Diesel Particulate Filter (DPF) Modeling and Development

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, Mark L.; Gallant, Thomas R.; Kim, Do Heui; Maupin, Gary D.; Zelenyuk, Alla

    2010-08-01

    The project described in this report seeks to promote effective diesel particulate filter technology with minimum fuel penalty by enhancing fundamental understanding of filtration mechanisms through targeted experiments and computer simulations. The overall backpressure of a filtration system depends upon complex interactions of particulate matter and ash with the microscopic pores in filter media. Better characterization of these phenomena is essential for exhaust system optimization. The acicular mullite (ACM) diesel particulate filter substrate is under continuing development by Dow Automotive. ACM is made up of long mullite crystals which intersect to form filter wall framework and protrude from the wall surface into the DPF channels. ACM filters have been demonstrated to effectively remove diesel exhaust particles while maintaining relatively low backpressure. Modeling approaches developed for more conventional ceramic filter materials, such as silicon carbide and cordierite, have been difficult to apply to ACM because of properties arising from its unique microstructure. Penetration of soot into the high-porosity region of projecting crystal structures leads to a somewhat extended depth filtration mode, but with less dramatic increases in pressure drop than are normally observed during depth filtration in cordierite or silicon carbide filters. Another consequence is greater contact between the soot and solid surfaces, which may enhance the action of some catalyst coatings in filter regeneration. The projecting crystals appear to provide a two-fold benefit for maintaining low backpressures during filter loading: they help prevent soot from being forced into the throats of pores in the lower porosity region of the filter wall, and they also tend to support the forming filter cake, resulting in lower average cake density and higher permeability. Other simulations suggest that soot deposits may also tend to form at the tips of projecting crystals due to the axial

  2. Dissolution Model Development: Formulation Effects and Filter Complications

    DEFF Research Database (Denmark)

    Berthelsen, Ragna; Holm, Rene; Jacobsen, Jette

    2016-01-01

    This study describes various complications related to sample preparation (filtration) during development of a dissolution method intended to discriminate among different fenofibrate immediate-release formulations. Several dissolution apparatus and sample preparation techniques were tested. The flow...... the mini paddle dissolution method demonstrates that sample preparation influenced the results. The investigations show that excipients from the formulations directly affected the drug–filter interaction, thereby affecting the dissolution profiles and the ability to predict the in vivo data....... With the tested drug–formulation combination, the best in vivo–in vitro correlation was found after filtration of the dissolution samples through 0.45-μm hydrophobic PTFE membrane filters....

  3. Does a Business Curriculum Develop or Filter Critical Thinking?

    Science.gov (United States)

    Coleman, B. Jay; Mason, Paul; Steagall, Jeffrey W.

    2012-01-01

    We investigate whether a business curriculum develops critical thinking ability or at least serves as a filter for critical thinking (i.e., students who cannot think critically tend not to progress toward graduation). We measure critical thinking by performance on the Watson-Glaser Critical Thinking Appraisal Short Form which was administered to a…

  4. Development of active porous medium filters based on plasma textiles

    Science.gov (United States)

    Kuznetsov, Ivan A.; Saveliev, Alexei V.; Rasipuram, Srinivasan; Kuznetsov, Andrey V.; Brown, Alan; Jasper, Warren

    2012-05-01

    Inexpensive, flexible, washable, and durable materials that serve as antimicrobial filters and self-decontaminating fabrics are needed to provide active protection to people in areas regularly exposed to various biohazards, such as hospitals and bio research labs working with pathogens. Airlines and cruise lines need such material to combat the spread of infections. In households these materials can be used in HVAC filters to fight indoor pollution, which is especially dangerous to people suffering from asthma. Efficient filtering materials are also required in areas contaminated by other types of hazardous dust particulates, such as nuclear dust. The primary idea that guided the undertaken study is that a microplasma-generating structure can be embedded in a textile fabric to generate a plasma sheath ("plasma shield") that kills bacterial agents coming in contact with the fabric. The research resulted in the development of a plasma textile that can be used for producing new types of self-decontaminating garments, fabrics, and filter materials, capable of activating a plasma sheath that would filter, capture, and destroy any bacteriological agent deposited on its surface. This new material relies on the unique antimicrobial and catalytic properties of cold (room temperature) plasma that is benign to people and does not cause thermal damage to many polymer textiles, such as Nomex and polypropylene. The uniqueness of cold plasma as a disinfecting agent lies in the inability of bacteria to develop resistance to plasma exposure, as they can for antibiotics. Plasma textiles could thus be utilized for microbial destruction in active antimicrobial filters (for continuous decontamination and disinfection of large amounts of air) as well as in self-decontaminating surfaces and antibacterial barriers (for example, for creating local antiseptic or sterile environments around wounds and burns).

  5. Improving search filter development: a study of palliative care literature

    Directory of Open Access Journals (Sweden)

    Tieman Jennifer

    2007-06-01

    Full Text Available Abstract Background It is difficult to systematically search for literature relevant to palliative care in general medical journals. A previously developed search filter for use on OVID Medline validated using a gold standard set of references identified through hand searching, achieved an unacceptably low sensitivity (45.4%. Retrieving relevant literature is integral to support evidence based practice, and understanding the nature of the incorrectly excluded citations (false negatives using the filter may lead to improvement in the filter's performance. Methods The objectives were to describe the nature of subjects reflected in the false negative citations and to empirically improve the sensitivity of the search filter. A thematic analysis of MeSH terms by three independent reviewers was used to describe the subject coverage of the missed records. Using a frequency analysis of MeSH terms, those headings which could individually contribute at least 2.5% to sensitivity (occurring 19 or more times were added to the search filter. All previously run searches were rerun at the same time as the revised filter, and results compared. Results Thematic analysis of MeSH terms identified thirteen themes reflected in the missing records, none of them intrinsically palliative. The addition of six MeSH terms to the existing search filter (physician-patient relations, prognosis, quality of life, survival rate, treatment outcome and attitude to health led to an increase in sensitivity from 46.3% to 64.7%, offset by a decrease in precision from 72.6% to 21.9%. Conclusion The filter's sensitivity was successfully increased using frequency analysis of MeSH terms, offset by a decrease in precision. A thematic analysis of MeSH terms for the false negative citations confirmed the absence of any intrinsically palliative theme or term, suggesting that future improvements to search filters for palliative care literature will first depend on better identifying how

  6. Influence of heat exchange of reservoir with rocks on hot gas injection via a single well

    Science.gov (United States)

    Nikolaev, Vladimir E.; Ivanov, Gavril I.

    2017-11-01

    In the computational experiment the influence of heat exchange through top and bottom of the gas-bearing reservoir on the dynamics of temperature and pressure fields during hot gas injection via a single well is investigated. The experiment was carried out within the framework of modified mathematical model of non-isothermal real gas filtration, obtained from the energy and mass conservation laws and the Darcy law. The physical and caloric equations of state together with the Newton-Riemann law of heat exchange of gas reservoir with surrounding rocks, are used as closing relations. It is shown that the influence of the heat exchange with environment on temperature field of the gas-bearing reservoir is localized in a narrow zone near its top and bottom, though the size of this zone is increased with time.

  7. Selective Laser Melting of Hot Gas Turbine Components: Materials, Design and Manufacturing Aspects

    DEFF Research Database (Denmark)

    Goutianos, Stergios

    2017-01-01

    are built additively to nearly net shape. This allows the fabrication of arbitrary complex geometries that cannot be made by conventional manufacturing techniques. However, despite the powerful capabilities of SLM, a number of issues (e.g. part orientation, support structures, internal stresses), have......Selective Laser Melting (SLM) allows the design and manufacturing of novel parts and structures with improved performance e.g. by incorporating complex and more efficient cooling schemes in hot gas turbine parts. In contrast to conventional manufacturing of removing material, with SLM parts...... to be considered in order to manufacture cost-effective and high quality parts at an industrial scale. These issues are discussed in the present work from an engineering point of view with the aim to provide simple quidelines to produce high quality SLM parts....

  8. Integral Hot Gas Pressure Forming of an AA2219 Aluminum Alloy Ellipsoidal Shell

    Science.gov (United States)

    Yuan, S. J.; Zhang, R.; Zhang, W. W.

    2017-04-01

    To overcome the poor plastic deformation performance of AA2219 aluminum alloy sheet and its weld seam at room temperature, an integral hot gas pressure forming (IHGPF) process for a combined welded ellipsoidal shell was proposed. A simulation of the IHGPF process was conducted to analyze the axis length variation and thickness distribution during the forming process of the combined welded ellipsoidal shell at elevated temperature. The results demonstrated that lengths of the short and long axes were 150 mm and 220 mm, respectively, and that maximum wall thinning occurred at the pole. Furthermore, an experiment was conducted using IHGPF, and the forming accuracy was measured by three-dimensional video technology. A sound ellipsoidal shell with final axis length ratio of 1.5 was obtained with a shell diameter accuracy of more than 99.3%. It was experimentally proven that an aluminum alloy ellipsoidal shell can be formed using the proposed IHGPF technology.

  9. Selective Laser Melting of Hot Gas Turbine Components: Materials, Design and Manufacturing Aspects

    DEFF Research Database (Denmark)

    Goutianos, Stergios

    2017-01-01

    Selective Laser Melting (SLM) allows the design and manufacturing of novel parts and structures with improved performance e.g. by incorporating complex and more efficient cooling schemes in hot gas turbine parts. In contrast to conventional manufacturing of removing material, with SLM parts...... to be considered in order to manufacture cost-effective and high quality parts at an industrial scale. These issues are discussed in the present work from an engineering point of view with the aim to provide simple quidelines to produce high quality SLM parts....... are built additively to nearly net shape. This allows the fabrication of arbitrary complex geometries that cannot be made by conventional manufacturing techniques. However, despite the powerful capabilities of SLM, a number of issues (e.g. part orientation, support structures, internal stresses), have...

  10. Hot gas stripping of ammonia and carbon dioxide from simulated and actual in situ retort waters

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, C.L.

    1979-01-01

    This study proved that ammonia and carbon dioxide could be removed from retort water by hot gas stripping and that overall transfer rates were slower than for physical desorption alone. The ammonia in solution complexed with the carbonate species with the result that the CO/sub 2/ transfer rates were linked to the relatively slower desorption of NH/sub 3/ from solution. Ionic reactions in the liquid phase limited the quantity of free NH/sub 3/ and CO/sub 2/, thus decreasing the driving forces for mass transfer. The retort water exhibited foaming tendencies that affected the interfacial area which should be taken into account if a stripping tower is considered on a larger scale. Transfer unit heights were calculated for the process conditions studied and correlated such that scaleup to increased capacities is possible.

  11. Selective Laser Melting of Hot Gas Turbine Components: Materials, Design and Manufacturing Aspects

    Science.gov (United States)

    Goutianos, Stergios

    2017-07-01

    Selective Laser Melting (SLM) allows the design and manufacturing of novel parts and structures with improved performance e.g. by incorporating complex and more efficient cooling schemes in hot gas turbine parts. In contrast to conventional manufacturing of removing material, with SLM parts are built additively to nearly net shape. This allows the fabrication of arbitrary complex geometries that cannot be made by conventional manufacturing techniques. However, despite the powerful capabilities of SLM, a number of issues (e.g. part orientation, support structures, internal stresses), have to be considered in order to manufacture cost-effective and high quality parts at an industrial scale. These issues are discussed in the present work from an engineering point of view with the aim to provide simple quidelines to produce high quality SLM parts.

  12. Investigation of austenitic alloys for advanced heat recovery and hot-gas cleanup systems

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    Materials properties were collected for the design and construction of structural components for use in advanced heat recovery and hot gas cleanup systems. Alloys systems included 9Cr-1Mo-V steel, modified 316 stainless steel, modified type 310 stainless steel, modified 20Cr-25Ni-Nb stainless steel, and modified alloy 800. Experimental work was undertaken to expand the databases for potentially useful alloys. Types of testing included creep, stress-rupture, creep-crack growth, fatigue, and post-exposure short-time tensile tests. Because of the interest in relatively inexpensive alloys for service at 700 C and higher, research emphasis was placed on a modified type 310 stainless steel and a modified 20Cr-25Ni-Nb stainless steel. Both steels were found to have useful strength to 925 C with good weldability and ductility.

  13. Investigation of austenitic alloys for advanced heat recovery and hot gas cleanup systems

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W.; Ren, W. [Oak Ridge National Lab., TN (United States)

    1996-08-01

    Materials properties were collected for the design and construction of structural components for use in advanced heat recovery and hot gas cleanup systems. Alloys systems included 9Cr-1Mo-V steel, modified 316 stainless steel, modified type 310 stainless steel, modified 20Cr-25Ni-Nb stainless steel, modified alloy 800, and two sulfidation resistant alloys: HR160 and HR120. Experimental work was undertaken to expand the databases for potentially useful alloys. Types of testing included creep, stress-rupture, creep-crack growth, fatigue, and post-exposure short-time tensile tests. Because of the interest in relatively inexpensive alloys for service at 700{degrees}C and higher, research emphasis was placed on a modified type 310 stainless steel and a modified 20Cr-25Ni-Nb stainless steel. Both steels were found to have useful strength to 925{degrees}C with good weldability and ductility.

  14. The scatter and evolution of the global hot gas properties of simulated galaxy cluster populations

    Science.gov (United States)

    Le Brun, Amandine M. C.; McCarthy, Ian G.; Schaye, Joop; Ponman, Trevor J.

    2017-04-01

    We use the cosmo-OverWhelmingly Large Simulation (cosmo-OWLS) suite of cosmological hydrodynamical simulations to investigate the scatter and evolution of the global hot gas properties of large simulated populations of galaxy groups and clusters. Our aim is to compare the predictions of different physical models and to explore the extent to which commonly adopted assumptions in observational analyses (e.g. self-similar evolution) are violated. We examine the relations between (true) halo mass and the X-ray temperature, X-ray luminosity, gas mass, Sunyaev-Zel'dovich (SZ) flux, the X-ray analogue of the SZ flux (YX) and the hydrostatic mass. For the most realistic models, which include active galactic nuclei (AGN) feedback, the slopes of the various mass-observable relations deviate substantially from the self-similar ones, particularly at late times and for low-mass clusters. The amplitude of the mass-temperature relation shows negative evolution with respect to the self-similar prediction (i.e. slower than the prediction) for all models, driven by an increase in non-thermal pressure support at higher redshifts. The AGN models predict strong positive evolution of the gas mass fractions at low halo masses. The SZ flux and YX show positive evolution with respect to self-similarity at low mass but negative evolution at high mass. The scatter about the relations is well approximated by log-normal distributions, with widths that depend mildly on halo mass. The scatter decreases significantly with increasing redshift. The exception is the hydrostatic mass-halo mass relation, for which the scatter increases with redshift. Finally, we discuss the relative merits of various hot gas-based mass proxies.

  15. Children's sense of reality: The development of orbitofrontal reality filtering

    OpenAIRE

    Liverani, Maria Chiara; Aurélie L. Manuel; Nahum, Louis; Guardabassi, Veronica; Tomasetto, Carlo; Schnider, Armin

    2015-01-01

    Orbitofrontal reality filtering denotes a memory control mechanism necessary to keep thought and behavior in phase with reality. In adults, it is mediated by the orbitofrontal cortex and subcortical connections and its failure induces reality confusion, confabulations, and disorientation. Here we investigated for the first time the development of this mechanism in 83 children from ages 7 to 11 years and 20 adults. We used an adapted version of a continuous recognition task composed of two run...

  16. Toward polarized antiprotons: Machine development for spin-filtering experiments

    Directory of Open Access Journals (Sweden)

    C. Weidemann

    2015-02-01

    Full Text Available The paper describes the commissioning of the experimental equipment and the machine studies required for the first spin-filtering experiment with protons at a beam kinetic energy of 49.3 MeV in COSY. The implementation of a low-β insertion made it possible to achieve beam lifetimes of τ_{b}=8000  s in the presence of a dense polarized hydrogen storage-cell target of areal density d_{t}=(5.5±0.2×10^{13}  atoms/cm^{2}. The developed techniques can be directly applied to antiproton machines and allow the determination of the spin-dependent p[over ¯]p cross sections via spin filtering.

  17. Properties of ceramic candle filters

    Energy Technology Data Exchange (ETDEWEB)

    Pontius, D.H.

    1995-06-01

    The mechanical integrity of ceramic filter elements is a key issue for hot gas cleanup systems. To meet the demands of the advanced power systems, the filter components must sustain the thermal stresses of normal operations (pulse cleaning), of start-up and shut-down conditions, and of unanticipated process upsets such as excessive ash accumulation without catastrophic failure. They must also survive the various mechanical loads associated with handling and assembly, normal operation, and process upsets. For near-term filter systems, these elements must survive at operating temperatures of 1650{degrees}F for three years.

  18. DEVELOPMENT OF OPTIMAL FILTERS OBTAINED THROUGH CONVOLUTION METHODS, USED FOR FINGERPRINT IMAGE ENHANCEMENT AND RESTORATION

    Directory of Open Access Journals (Sweden)

    Cătălin LUPU

    2014-12-01

    Full Text Available This article presents the development of optimal filters through covolution methods, necessary for restoring, correcting and improving fingerprints acquired from a sensor, able to provide the most ideal image in the output. After the image was binarized and equalized, Canny filter is applied in order to: eliminate the noise (filtering the image with a Gaussian filter, non-maxima suppression, module gradient adaptive binarization and extension edge points edges by hysteresis. The resulting image after applying Canny filter is not ideal. It is possible that the result will be an image with very fragmented edges and many pores in ridge. For the resulting image, a bank of convolution filters are applied one after another (Kirsch, Laplace, Roberts, Prewitt, Sobel, Frei-Chen, averaging convolution filter, circular convolution filter, lapacian convolution filter, gaussian convolution filter, LoG convolution filter, DoG, inverted filters, Wiener, the filter of ”equalization of the power spectrum” (intermediary filter between the Wiener filter and the inverted filter, the geometrical average filter , etc. with different features.

  19. Development of Phase-Only Filters for Sensor Imagery

    Science.gov (United States)

    1993-12-01

    results of our statistically-designed filters to that of an fSDF filter. An fSDF filter is an iteratively designed, equal-correlation peak filter that...takes into account spatial light modulator (SLM) modulation characteristics. 5 Therefore, an fSDF filter was designed to produce equal correlation...heights for the training set using a BPOF. The average PCE value of the raining set using the fSDF filter was 140.7, which was higher than the values

  20. Electron beam weld development on a Filter Pack Assembly

    Science.gov (United States)

    Dereskiewicz, J. P.

    1994-06-01

    A continuous electron beam welding procedure was developed to replace the manual gas tungsten arc welding procedure on the Filter Pack Assembly. A statistical study was used to evaluate the feasibility of electron beam welding 6061-T6 aluminum covers to A356 cast weldments throughout the joint tolerance range specified on product drawings. Peak temperature exposures were not high enough to degrade the heat sensitive electrical components inside the cast weldment. Actual weldments with alodine coating on the weld joint area were successfully cleaned using a nonmetallic fiberglass brush cleaning method.

  1. Assessment of high-temperature filtering elements

    Energy Technology Data Exchange (ETDEWEB)

    Monica Lupion; Francisco J. Gutierrez Ortiz; Benito Navarrete; Vicente J. Cortes [University of Seville, Seville (Spain). E.T.S. Ingenieros

    2008-07-01

    A complete experimental campaign has been carried out in a hot gas filtration test facility so as to test several filtering elements and configurations, particularly, three different types of bag filters and one ceramic candle. The facility was designed to operate under a wide range of conditions, thus providing an excellent tool for the investigation of hot gas filtration applications for the advanced electrical power generation industry such as IGCC, PFBC or fuel cell technologies. Relevant parameters for the characterization and optimization of the performance of the filters have been studied for a variety of operation conditions such as filtration velocity, particle concentration, pressure and temperature among others. Pressure drop across the filter, cleaning pulse interval, baseline pressure drop, filtration efficiency and durability of the filter have been investigated for each type considered and dependences on parameters have been established. On top of that, optimal operating conditions and cleaning strategies were determined. The tests results show that bag filters are a suitable alternative for the hot gas filtration due to the better performance and the high efficiency observed, which makes them suitable for industrial applications operating under high temperature high pressure conditions considered within the study (200-370{degree}C and 4-7.5 barg respectively). 7 refs., 7 figs., 10 tabs.

  2. The hot gas cleaning with multifunctional sorbent technique at 1-20 bar pressure; Kaasujen kuumapuhdistus multifunktionaalisella sorbenttitekniikalla 1-20 bar:n paineessa

    Energy Technology Data Exchange (ETDEWEB)

    Jaanu, K.; Orjala, M.; Paakkinen, K.; Rantanen, J. [VTT Energy, Espoo (Finland)

    1996-12-01

    The aim of the research was to study the simultaneous hot gas cleanup of alkali metals and selected heavy metals under pressure of 1-20 bar using multifunctional sorbent technology, to investigate effects of it on sulfur and nitrogen emissions and to improve the total efficiency of the hot gas cleanup method by reducing the concentrations of harmful components to the level required by the gas turbines. The research has started in the year 1993. The optimization of the test facility at 900 deg C and 20 bar has been accomplished, as targeted. The main topics have been the alkali metals. The main targets of the year 1994 was to concentrate on the research of sorbent effectiveness to remove the impurities like alkalies etc. from the flue gas. Furthermore researches on kinetics and mechanisms were started. The results showed that the developed multifunctional sorbent are highly effective to remove alkalies from the flue gas. Also a mechanism for alkali and lead sorption was proposed. The main topics for 1995 were scheduled to be the completion of the kinetic and mechanical studies and the modelling and the estimation of the data for the pilot scale unit. The kinetic data for one sorbent has been completed and a model for that has also been developed. The measured and calculated results are indicating that the developed multifunctional sorption process is highly effective to remove alkalies and heavy metals such as lead and cadmium from high-temperature combustion gases. The tests are carried out mainly using the pressurized entrained flow reactor of VTT Energy, located in Jyvaeskylae, and in the university of Arizona, where the tests are conducted under atmospheric pressure. Some comparisons of the results might be made with those of Aabo Akademi during the future modelling. 3. The results are applied to purification of the hot gases in boilers, power and process industry. (Abstract Truncated)

  3. A Simple Candle Filter Safeguard Device

    Energy Technology Data Exchange (ETDEWEB)

    Hurley, J.P.; Henderson, A.K.; Swanson, M.L.

    2002-09-18

    In order to reach the highest possible efficiencies in a coal-fired turbine-based power system, the turbine should be directly fired with the products of coal utilization. Two main designs employ these turbines: those based on pressurized fluidized-bed combustors (PFBCs) and those based on integrated gasification combined cycles (IGCCs). In both designs, the suspended particulates, or dust, must be cleaned from the gas before it enters the turbine to prevent fouling and erosion of the blades. To produce the cleanest gas, barrier filters are being developed and are in commercial use. Barrier filters are composed of porous, high-temperature materials that allow the hot gas to pass but collect the dust on the surface. The three main configurations are candle, cross-flow, and tube. Both candle and tube filters have been tested extensively. They are primarily composed of coarsely porous ceramic that serves as a structural support, overlain with a thin, microporous ceramic layer o n the dirty gas side that serves as the primary filter surface. They are highly efficient at removing particulate matter from the gas stream and, because of their ceramic construction, are resistant to gas and ash corrosion. However, ceramics are brittle, and individual elements can fail, allowing the particulates to pass through the hole left by the filter element and erode the turbine. Because of the possibility of occasional filter breakage, safeguard devices (SGDs) must be employed to prevent the dust streaming through broken filters from reaching the turbine. The Energy & Environmental Research Center (EERC) safeguard device is composed of three main parts: the ceramic substrate, the adhesive coating, and the safeguard device housing. This report describes the development and laboratory testing of each of those parts as well as the bench-scale performance of both types of complete SGDs.

  4. Development of Drabkin energy filters for J-PARC project

    CERN Document Server

    Yamazaki, D; Soyama, K; Tasaki, S

    2003-01-01

    In the J-PARC project, the high intensity spallation neutron source has been developed. Very intensive pulsed neutron beam will be available from a coupled moderator installed at the spallation source. Wavelengths of neutrons is generally determined by its time-of-flight (TOF) from the source to the detector, but the available precision is limited by the non-zero emission time-width of the moderator system. It follows that high precision experiments cannot be performed with the intensive pulsed neutrons from the coupled moderator. We have been developing Drabkin energy filters, which effectively reduces the emission time-width by the spatial neutron spin resonance. In this paper, firstly, we describe the physics in the Drabkin spin flipper, which is the main part of the Drabkin energy filter, and derive the spin-flip probability by the flipper in the quantum-mechanical manner. Secondly, the properties of the resonance spin flipping are described. Thirdly, sweep mode for the application to pulsed neutrons are ...

  5. Particulate hot gas stream cleanup technical issues. Annual report, October 1994--September 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-19

    This is the first annual report describing the activities performed under Contract No. DE-AC21-94MC31160. Task I of this contract is concerned with the analyses of HGCU ashes and descriptions of filter performance and is designed to address the problems with filter operation that are apparently linked to the characteristics of the collected ash. Task 2 of this contract includes characterization of new and used filter elements. Some of the problems observed at the Tidd and Karhula PFBC facilities include excessive filtering pressure drop, the formation of large, tenacious ash deposits within the filter vessel, and bent or broken candle filter elements. In addition to these problems related to the characteristics of PFBC ashes and the ceramic materials used to construct candle filters, our previous laboratory characterizations of gasifier and carbonizer ashes have shown that these ashes also have characteristics that might negatively affect filtration.

  6. The Hot-gas screw-type engine - Simulation as a basis for construction. Pt. 3; Die Heissgasschraubenmaschine - simulationsgestuetzte Auslegung. T. 3

    Energy Technology Data Exchange (ETDEWEB)

    Kauder, K.; Unwerth, T. von [Dortmund Univ. (Germany). FG Fluidenergiemaschinen

    1998-12-31

    In this paper new results of the research regarding the design of the first experimental plant for a hot-gas screw-type machine are reported. Target of the development is the verification of operating behaviour as well as the thermal and mechanical behaviour of the screw-type motor parts. The selection and dimensioning of the plant components is described with a main focus on the construction of the thermally high-loaded hot-gas screw-type engine. Its manufacturing tolerances are based on simulations, with which the mechanical deformations of the rotors and the casing respective the resulting clearance-heights can be calculated. With inclusion of an efficient cooling method for the motor parts, for the, in the article documented, projected nominal working condition with a material-depending limit for the entrance temperature at {theta}{sub E,} {sub M}=600 C, a pressure ratio {pi}=6 and a male rotor peripheral speed u{sub HR}=120 ms{sup -1}, each rotor should be decreased by 0.07 mm. (orig.) [Deutsch] Es wird ueber neue Forschungsergebnisse im Hinblick auf die konstruktive Realisierung der ersten Versuchsanlage einer Heissgasschraubenmaschine berichtet. Ziel der daran durchgefuehrten Untersuchungen ist die Verifikation des Betriebsverhaltens sowie des thermischen und mechanischen Bauteilverhaltens des Heissgasschraubenmotors. Nachzulesen ist die Auswahl und Dimensionierung der Anlagenkomponenten, wobei ein Hauptaugenmerk auf der Auslegung des thermisch hoch belasteten Schraubenmotors liegt. Dessen Dimensionierung liegen Simulationsrechnungen zugrunde, mit deren Hilfe die mechanischen Verformungen der Rotoren und des Gehaeuses respektive der daraus resultierenden Spalthoehen a priori angegeben werden koennen. Fuer den hier dokumentierten, angestrebten Nennbetriebszustand mit einer werkstoffbedingt begrenzten Motoreintrittstemperatur von {theta}{sub E,} {sub M}=600 C, einem Druckverhaeltnis von {pi}=6 und einer Hauptrotorumfangsgeschwindigkeit von u{sub HR}=120 ms

  7. Development and evaluation of evidence-based nursing (EBN) filters and related databases.

    Science.gov (United States)

    Lavin, Mary A; Krieger, Mary M; Meyer, Geralyn A; Spasser, Mark A; Cvitan, Tome; Reese, Cordie G; Carlson, Judith H; Perry, Anne G; McNary, Patricia

    2005-01-01

    Difficulties encountered in the retrieval of evidence-based nursing (EBN) literature and recognition of terminology, research focus, and design differences between evidence-based medicine and nursing led to the realization that nursing needs its own filter strategies for evidence-based practice. This article describes the development and evaluation of filters that facilitate evidence-based nursing searches. An inductive, multistep methodology was employed. A sleep search strategy was developed for uniform application to all filters for filter development and evaluation purposes. An EBN matrix was next developed as a framework to illustrate conceptually the placement of nursing-sensitive filters along two axes: horizontally, an adapted nursing process, and vertically, levels of evidence. Nursing diagnosis, patient outcomes, and primary data filters were developed recursively. Through an interface with the PubMed search engine, the EBN matrix filters were inserted into a database that executes filter searches, retrieves citations, and stores and updates retrieved citations sets hourly. For evaluation purposes, the filters were subjected to sensitivity and specificity analyses and retrieval set comparisons. Once the evaluation was complete, hyperlinks providing access to any one or a combination of completed filters to the EBN matrix were created. Subject searches on any topic may be applied to the filters, which interface with PubMed. Sensitivity and specificity for the combined nursing diagnosis and primary data filter were 64% and 99%, respectively; for the patient outcomes filter, the results were 75% and 71%, respectively. Comparisons were made between the EBN matrix filters (nursing diagnosis and primary data) and PubMed's Clinical Queries (diagnosis and sensitivity) filters. Additional comparisons examined publication types and indexing differences. Review articles accounted for the majority of the publication type differences, because "review" was accepted by

  8. Development of Drabkin energy filters for J-PARC project

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, Dai; Soyama, Kazuhiko; Ebisawa, Toru [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Tasaki, Seiji [Kyoto Univ., Kyoto (Japan)

    2003-03-01

    In the J-PARC project, the high intensity spallation neutron source has been developed. Very intensive pulsed neutron beam will be available from a coupled moderator installed at the spallation source. Wavelengths of neutrons is generally determined by its time-of-flight (TOF) from the source to the detector, but the available precision is limited by the non-zero emission time-width of the moderator system. It follows that high precision experiments cannot be performed with the intensive pulsed neutrons from the coupled moderator. We have been developing Drabkin energy filters, which effectively reduces the emission time-width by the spatial neutron spin resonance. In this paper, firstly, we describe the physics in the Drabkin spin flipper, which is the main part of the Drabkin energy filter, and derive the spin-flip probability by the flipper in the quantum-mechanical manner. Secondly, the properties of the resonance spin flipping are described. Thirdly, sweep mode for the application to pulsed neutrons are described and the effects of the field sweeping to the spin-flip probabilities were numerically demonstrated. Suppressions of sub-peaks in the resonance spin flipping by modulated magnetic fields are also demonstrated numerically. We have developed Drabkin flippers with 10 periods of field and carried out performance test of the flipper at JRR-3M. Firstly, field dependency of the spin-flip probability was measured with monochromatic beam ({lambda}=8.8 A, FWHM 2.5%). Secondly, wavelength dependency of the spin-flip probability was measured with chopped beam ({lambda}=8.3 A, FWHM 14.9%). The results were consistent with the expected values by numerical calculations. (author)

  9. Development of ultrastable filters and lasers for solar seismology

    Science.gov (United States)

    Rust, D. M.; Kunski, R.; Cohn, R. F.

    1986-01-01

    The Stable Solar Analyzer is a recently developed instrument for the measurement of solar magnetic fields and surface velocities that is being employed at the U.S. National Solar Observatory to study the subsurface convection cells of the sun and the structure of surface and subsurface magnetic fields. The Analyzer is expected to ultimately be flown aboard such spacecraft as the ESA/NASA Solar and Heliospheric Observatory. This instrument is based on a crystalline lithium niobate Fabry-Perot filter that is used in conjunction with a stabilized laser that furnishes an absolute wavelength reference; this laser Fabry-Perot combination has achieved wavelength stabilities of the order of 2 parts in 10 to the 10th, over a six-hour interval.

  10. High-temperature high-pressure gas cleanup with ceramic bag filters. Draft final report

    Energy Technology Data Exchange (ETDEWEB)

    Shackleton, M.; Chang, R.; Sawyer, J.; Kuby, W.; Turner-Tamiyasu, E.

    1982-12-06

    Advanced processes designed for the efficient use of coal in the production of energy will benefit from, or even depend upon, highly efficient, economical, high-temperature removal systems for fine particulates. In the case of pressurized fluidized-bed combustion (PFBC), the hot gas cleanup device must operate at approximately 1600/sup 0/F. Existing commercial filter systems are temperature limited due to the filter material, but ceramic fibers intended for refractory insulation offer the promise of a practical high-temperature filter media if they can be incorporated into a design which combines filter performance with acceptable durability. The current work was initiated to further develop and demonstrate on a larger-scale basis, a ceramic fiber filtration system for application to coal-fired PFBC's. The development effort centered around the need to replace the knit metal wire scrim, used in earlier designs as support for the fine fiber ceramic mat filtration medium, with a corrosion-resistant material. This led to the selection of woven ceramic cloth for support of the mat layer. Because of the substantial difference in strength and other material properties between the metal and ceramic cloth, tests were necessary to optimize the filter; pulse parameters such as pulse duration, pulse pressure, and pulse injection orifice size; woven cloth mesh configuration; the technique for clamping the bag to the support; and similar structural, fluid, and control parameters. The demonstration effort included both tests to prove this concept in a real application and a systems analysis to show commercial feasibility of the ceramic filtration approach for hot gas cleanup in PFBC's. 12 references, 57 figures, 23 tables.

  11. Particulate hot gas stream cleanup technical issues. Quarterly report, April--June 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-08-01

    This is the third in a series of quarterly reports. Analyses of HGCU ashes and descriptions of filter performance are designed to address aspects of filter operation apparently linked to properties of the collected ash. Task 1 is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters and to relate these ash properties to the operation and performance of these filters and their components. Task 2 concerns testing and failure analysis of ceramic filters. Mechanical and thermal testing of Dupont/Lanxide PRD-66, Dupont composite, 3M composite, and IF and P Fibrosics is continuing. Thermal expansion values of the PRD-66, 3M composite, and IF and P Fibrosics were measured at 1500{degree}F. Testing of new Refractron and Schumacher candle filter materials is in progress. No creep was detected for the Refractron specimens after {approx}150 hr at 1550{degree}F and creep testing is proceeding at 1600{degree}F. Machined Schumacher creep specimens will be tested following completion of the Refractron tests.

  12. Glomerular disease search filters for Pubmed, Ovid Medline, and Embase: a development and validation study.

    Science.gov (United States)

    Hildebrand, Ainslie M; Iansavichus, Arthur V; Lee, Christopher W C; Haynes, R Brian; Wilczynski, Nancy L; McKibbon, K Ann; Hladunewich, Michelle A; Clark, William F; Cattran, Daniel C; Garg, Amit X

    2012-06-06

    Tools to enhance physician searches of Medline and other bibliographic databases have potential to improve the application of new knowledge in patient care. This is particularly true for articles about glomerular disease, which are published across multiple disciplines and are often difficult to track down. Our objective was to develop and test search filters for PubMed, Ovid Medline, and Embase that allow physicians to search within a subset of the database to retrieve articles relevant to glomerular disease. We used a diagnostic test assessment framework with development and validation phases. We read a total of 22,992 full text articles for relevance and assigned them to the development or validation set to define the reference standard. We then used combinations of search terms to develop 997,298 unique glomerular disease filters. Outcome measures for each filter included sensitivity, specificity, precision, and accuracy. We selected optimal sensitive and specific search filters for each database and applied them to the validation set to test performance. High performance filters achieved at least 93.8% sensitivity and specificity in the development set. Filters optimized for sensitivity reached at least 96.7% sensitivity and filters optimized for specificity reached at least 98.4% specificity. Performance of these filters was consistent in the validation set and similar among all three databases. PubMed, Ovid Medline, and Embase can be filtered for articles relevant to glomerular disease in a reliable manner. These filters can now be used to facilitate physician searching.

  13. Investigating the Potential Dilution of the Metal Content of Hot Gas in Early-Type Galaxies by Accreted Cold Gas

    OpenAIRE

    Su, Yuanyuan; Irwin, Jimmy

    2013-01-01

    The measured emission-weighted metal abundance of the hot gas in early-type galaxies has been known to be lower than theoretical expectations for 20 years. In addition, both X-ray luminosity and metal abundance vary significantly among galaxies of similar optical luminosities. This suggests some missing factors in the galaxy evolution process, especially the metal enrichment process. With {\\it Chandra} and {\\it XMM-Newton}, we studied 32 early-type galaxies (kT $\\lesssim$ 1 keV) covering a sp...

  14. Moving Bed Granular Bed Filter Development Program. Topical report, September 1994

    Energy Technology Data Exchange (ETDEWEB)

    Haas, J.C.; Prudhomme, J.W.; Wilson, K.W.

    1994-09-01

    Five test arrangements have been designed to support the Granular Bed Filter Development Program as defined in the Test Plan. The first arrangement is a 3.6 ft. diameter half filter, with a glass covering along the cross section to allow visual examination of the granular alumina material passing through the filter. The second test arrangement is a 3.6 ft diameter full size filter having refractory lining to simulate actual surface roughness conditions. The third test arrangement will examine filter geometry scale up by testing a 6.0 ft. diameter full size filter. The fourth Test Arrangement consists of a small 12 inch diameter fluidizer to measure the minimum fluidization velocity of the 7 m (approx. size) alumina material to be used in the filter assemblies. The last Test Unit is used to evaluation relative abrasion characteristics of potential refractory and ceramic materials to be installed in high abrasion areas in the pneumatic transport piping.

  15. ELECTROSTATICALLY ENHANCED BARRIER FILTER COLLECTION

    Energy Technology Data Exchange (ETDEWEB)

    John Erjavec; Michael D. Mann; Ryan Z. Knutson; Michael L. Swanson; Michael E. Collings

    2003-06-01

    This work was performed through the University of North Dakota (UND) Chemical Engineering Department with assistance from UND's Energy & Environmental Research Center. This research was undertaken in response to the U.S. Department of Energy Federal Technology Center Program Solicitation No. DE-PS26-99FT40479, Support of Advanced Coal Research at U.S. Universities and Colleges. Specifically, this research was in support of the UCR Core Program and addressees Topic 1, Improved Hot-Gas Contaminant and Particulate Removal Techniques, introducing an advanced design for particulate removal. Integrated gasification combined cycle (IGCC) offers the potential for very high efficiency and clean electric generation. In IGCC, the product gas from the gasifier needs to be cleaned of particulate matter to avoid erosion and high-temperature corrosion difficulties arising with the turbine blades. Current methods involve cooling the gases to {approx}100 C to condense alkalis and remove sulfur and particulates using conventional scrubber technology. This ''cool'' gas is then directed to a turbine for electric generation. While IGCC has the potential to reach efficiencies of over 50%, the current need to cool the product gas for cleaning prior to firing it in a turbine is keeping IGCC from reaching its full potential. The objective of the current project was to develop a highly reliable particulate collector system that can meet the most stringent turbine requirements and emission standards, can operate at temperatures above 1500 F, is applicable for use with all U.S. coals, is compatible with various sorbent injection schemes for sulfur and alkali control, can be integrated into a variety of configurations for both pressurized gasification and combustion, increases allowable face velocity to reduce filter system capital cost, and is cost-competitive with existing technologies. The collector being developed is a new concept in particulate control called

  16. The filter wheel and filters development for the X-IFU instruments onboard Athena

    Science.gov (United States)

    Bozzo, E.; Barbera, M.; Genolet, L.; Paltani, S.; Sordet, M.; Branduardi-Raymont, G.; Rauw, G.; Sciortino, S.; Barret, D.; Den Herder, J. W.

    2016-07-01

    Athena is the large mission selected by ESA in 2013 to investigate the science theme "Hot and Energetic Universe" and presently scheduled for launch in 2028. One of the two instruments located at the focus of the 12 m-long Athena telescope is the X-ray Integral Field Unit (X-IFU). This is an array of TES microcalorimeters that will be operated at temperatures of 50 mK in order to perform high resolution spectroscopy with an energy resolution down to 2.5 eV at energies < 7 keV. In order to cope with the large dynamical range of X-ray fluxes spanned by the celestial objects Athena will be observing, the X-IFU will be equipped with a filter wheel. This will allow the user to fine tune the instrument set-up based on the nature of the target, thus optimizing the scientific outcomes of the observation. A few positions of the filter wheel will also be used to host a calibration source and to allow the measurement of the instrument intrinsic background.

  17. Developing topic-specific search filters for PubMed with click-through data.

    Science.gov (United States)

    Li, J; Lu, Z

    2013-01-01

    Search filters have been developed and demonstrated for better information access to the immense and ever-growing body of publications in the biomedical domain. However, to date the number of filters remains quite limited because the current filter development methods require significant human efforts in manual document review and filter term selection. In this regard, we aim to investigate automatic methods for generating search filters. We present an automated method to develop topic-specific filters on the basis of users' search logs in PubMed. Specifically, for a given topic, we first detect its relevant user queries and then include their corresponding clicked articles to serve as the topic-relevant document set accordingly. Next, we statistically identify informative terms that best represent the topic-relevant document set using a background set composed of topic irrelevant articles. Lastly, the selected representative terms are combined with Boolean operators and evaluated on benchmark datasets to derive the final filter with the best performance. We applied our method to develop filters for four clinical topics: nephrology, diabetes, pregnancy, and depression. For the nephrology filter, our method obtained performance comparable to the state of the art (sensitivity of 91.3%, specificity of 98.7%, precision of 94.6%, and accuracy of 97.2%). Similarly, high-performing results (over 90% in all measures) were obtained for the other three search filters. Based on PubMed click-through data, we successfully developed a high-performance method for generating topic-specific search filters that is significantly more efficient than existing manual methods. All data sets (topic-relevant and irrelevant document sets) used in this study and a demonstration system are publicly available at http://www.ncbi.nlm.nih.gov/CBBresearch/Lu/downloads/CQ_filter/

  18. Assessment performance of high-temperature filtering elements

    Energy Technology Data Exchange (ETDEWEB)

    Monica Lupion; Francisco J. Gutierrez Ortiz; Benito Navarrete; Vicente J. Cortes [University of Seville, Seville (Spain). E.T.S. Ingenieros

    2010-04-15

    An extensive experimental campaign has been carried out in a hot gas filtration test facility so as to test several filtering elements and configurations, particularly, three different types of bag filters and one ceramic candle. The facility was designed to operate under a wide range of conditions, thus providing an excellent tool for the investigation of hot gas filtration applications for the advanced electrical power generation industry such as IGCC, PFBC or fuel cell technologies. Relevant parameters for the characterisation and optimization of the performance of the filters have been studied for a variety of operating conditions such as filtration velocity, particle concentration, pressure and temperature among others. Pressure drop across the filter, cleaning pulse interval, baseline pressure drop, filtration efficiency and durability of the filter have been investigated for each type considered and dependences on parameters have been established. On top of that, optimal operating conditions and cleaning strategies were determined. The tests results show that bag filters are a suitable alternative for the hot gas filtration due to the better performance and the high efficiency observed, which makes them suitable for industrial applications operating under high temperature high pressure conditions considered within the study (200-370{sup o}C and 4-7.5 barg, respectively). 8 refs., 7 figs., 10 tabs.

  19. The development of the spatially correlated adjustment wavelet filter for atomic force microscopy data.

    Science.gov (United States)

    Sikora, Andrzej; Rodak, Aleksander; Unold, Olgierd; Klapetek, Petr

    2016-12-01

    In this paper a novel approach for the practical utilization of the 2D wavelet filter in terms of the artifacts removal from atomic force microscopy measurements results is presented. The utilization of additional data such as summary photodiode signal map is implemented in terms of the identification of the areas requiring the data processing, filtering settings optimization and the verification of the process performance. Such an approach allows to perform the filtering parameters adjustment by average user, while the straightforward method requires an expertise in this field. The procedure was developed as the function of the Gwyddion software. The examples of filtering the phase imaging and Electrostatic Force Microscopy measurement result are presented. As the wavelet filtering feature may remove a local artifacts, its superior efficiency over similar approach with 2D Fast Fourier Transformate based filter (2D FFT) can be noticed. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Tandem Filter Development for Thermophotovoltaic Energy Conversion from January 2003 to February 2006

    Energy Technology Data Exchange (ETDEWEB)

    Fourspring PM

    2007-03-19

    The intent of this report is to summarize the tandem filter development for spectral control of thermophotovoltaic energy conversion from January 2003 to the termination of the program in February 2006 and to closeout tandem filter development in order to capture the knowledge gained from the development effort. Over the last three years, the goals of the tandem filter development have been the following: (1) Study the limits of the design of the interference optical coatings component of a tandem filter in order to develop higher performance designs; (2) Enhance the fabrication process of the optical interference coatings to increase the fidelity with the intended design and allow more complex, higher performing designs; (3) Support TPV module testing by providing tandem filters and assembly assistance; (4) Identify and develop materials for optical interference coatings that are stable at higher temperatures than current materials; and (5) Improve the understanding of the directional and spectral reflectance and transmittance characterization of the completed tandem filters to insure the veracity of the characterization data and to provide useful feedback to the tandem filter development process. This development effort has been a collaboration between KAPL and its contracted development partner, Rugate Technologies Inc.

  1. Development of a wavelength tunable filter using MEMS technology

    Science.gov (United States)

    Liu, Junting

    Microelectromechanical systems (MEMS) for optical applications have received intensive attention in recent years because of their potential applications in optical telecommunication. Traditional wavelength division multiplexing (WDM) offers high capacity but requires the fabrication of selective add-drop filters. MEMS technology offers an effective way to fabricate these components at low cost. This thesis presents the development of a device that tunes the Bragg wavelength by coupling into the evanescent field of the grating. A Bragg grating is a periodic perturbation of the refractive index along a fiber or a periodic perturbation of the structure of a planar waveguide. The Bragg wavelength can be tuned by changing the degree to which a dielectric slab couples into the evanescent field. The result is a change in the effective index of the grating, and thus a change in the wavelength that which it reflects. In this thesis Bragg gratings were successfully written into an optical fiber using phase mask technique. Mechanical polishing was used to side-polish the fiber and remove cladding to expose the core. Grating structures were also fabricated in planar waveguide using E-beam writing and dry etching. In order to achieve the smoothest possible morphology of the waveguide, plasma dry etching of transparent substrates was studied in great detail. It is found that the pre-etch cleaning procedure greatly influences the ability to obtain a smooth etched surface. Upper limits of evanescent field tuning were investigated by applying different index liquids such as D. I. water and index matching oils or by positioning different dielectric materials such as glass and silicon close to the grating. Planar waveguides were found to be more sensitive to effective index change. Two kinds of computer simulation were carried out to understand the mode profile and to estimate the value of effective index of planar waveguide under "dry" and "wet" conditions. The first one used an

  2. Space shuttle navigation filter development. [data processor for radar tracking data

    Science.gov (United States)

    Lear, W. M.

    1976-01-01

    Problems encountered in developing a high speed trajectory data processor for the shuttle ascent and entry phases are described. The development of a 19 state acceleration filter for the processor is reported.

  3. Development and Validation of Search Filters to Identify Articles on Family Medicine in Online Medical Databases

    NARCIS (Netherlands)

    Pols, D.H.; Bramer, W.M.; Bindels, P.J.E.; Laar, F.A. van de; Bohnen, A.M.

    2015-01-01

    Physicians and researchers in the field of family medicine often need to find relevant articles in online medical databases for a variety of reasons. Because a search filter may help improve the efficiency and quality of such searches, we aimed to develop and validate search filters to identify

  4. Development and validation of search filters to identify articles on family medicine in online medical databases

    NARCIS (Netherlands)

    D.H.J. Pols (David); W.M. Bramer (Wichor); P.J.E. Bindels (Patrick); F.A. van de Laar (Floris A.); A.M. Bohnen (Arthur)

    2015-01-01

    textabstractPhysicians and researchers in the field of family medicine often need to find relevant articles in online medical databases for a variety of reasons. Because a search filter may help improve the efficiency and quality of such searches, we aimed to develop and validate search filters to

  5. CONSTRAINING THE MILKY WAY'S HOT GAS HALO WITH O VII AND O VIII EMISSION LINES

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Matthew J.; Bregman, Joel N., E-mail: mjmil@umich.edu, E-mail: jbregman@umich.edu [Department of Astronomy, University of Michigan, Ann Arbor, MI 48104 (United States)

    2015-02-10

    The Milky Way hosts a hot (≈2 × 10{sup 6} K), diffuse, gaseous halo based on detections of z = 0 O VII and O VIII absorption lines in quasar spectra and emission lines in blank-sky spectra. Here we improve constraints on the structure of the hot gas halo by fitting a radial model to a much larger sample of O VII and O VIII emission line measurements from XMM-Newton/EPIC-MOS spectra compared to previous studies (≈650 sightlines). We assume a modified β-model for the halo density distribution and a constant-density Local Bubble from which we calculate emission to compare with the observations. We find an acceptable fit to the O VIII emission line observations with χ{sub red}{sup 2} (dof) = 1.08 (644) for best-fit parameters of n{sub o}r{sub c}{sup 3β}=1.35±0.24 cm{sup –3} kpc{sup 3β} and β = 0.50 ± 0.03 for the hot gas halo and negligible Local Bubble contribution. The O VII observations yield an unacceptable χ{sub red}{sup 2} (dof) = 4.69 (645) for similar best-fit parameters, which is likely due to temperature or density variations in the Local Bubble. The O VIII fitting results imply hot gas masses of M(<50 kpc) = 3.8{sub −0.3}{sup +0.3}×10{sup 9} M{sub ⊙} and M(<250 kpc) = 4.3{sub −0.8}{sup +0.9}×10{sup 10} M{sub ⊙}, accounting for ≲50% of the Milky Way's missing baryons. We also explore our results in the context of optical depth effects in the halo gas, the halo gas cooling properties, temperature and entropy gradients in the halo gas, and the gas metallicity distribution. The combination of absorption and emission line analyses implies a sub-solar gas metallicity that decreases with radius, but that also must be ≥0.3 Z {sub ☉} to be consistent with the pulsar dispersion measure toward the Large Magellanic Cloud.

  6. Development and validation of filters for the retrieval of studies of clinical examination from Medline.

    Science.gov (United States)

    Shaikh, Nader; Badgett, Robert G; Pi, Mina; Wilczynski, Nancy L; McKibbon, K Ann; Ketchum, Andrea M; Haynes, R Brian

    2011-10-19

    Efficiently finding clinical examination studies--studies that quantify the value of symptoms and signs in the diagnosis of disease-is becoming increasingly difficult. Filters developed to retrieve studies of diagnosis from Medline lack specificity because they also retrieve large numbers of studies on the diagnostic value of imaging and laboratory tests. The objective was to develop filters for retrieving clinical examination studies from Medline. We developed filters in a training dataset and validated them in a testing database. We created the training database by hand searching 161 journals (n = 52,636 studies). We evaluated the recall and precision of 65 candidate single-term filters in identifying studies that reported the sensitivity and specificity of symptoms or signs in the training database. To identify best combinations of these search terms, we used recursive partitioning. The best-performing filters in the training database as well as 13 previously developed filters were evaluated in a testing database (n = 431,120 studies). We also examined the impact of examining reference lists of included articles on recall. In the training database, the single-term filters with the highest recall (95%) and the highest precision (8.4%) were diagnosis[subheading] and "medical history taking"[MeSH], respectively. The multiple-term filter developed using recursive partitioning (the RP filter) had a recall of 100% and a precision of 89% in the training database. In the testing database, the Haynes-2004-Sensitive filter (recall 98%, precision 0.13%) and the RP filter (recall 89%, precision 0.52%) showed the best performance. The recall of these two filters increased to 99% and 94% respectively with review of the reference lists of the included articles. Recursive partitioning appears to be a useful method of developing search filters. The empirical search filters proposed here can assist in the retrieval of clinical examination studies from Medline; however, because of

  7. Glomerular disease search filters for Pubmed, Ovid Medline, and Embase: a development and validation study

    Directory of Open Access Journals (Sweden)

    Hildebrand Ainslie M

    2012-06-01

    Full Text Available Abstract Background Tools to enhance physician searches of Medline and other bibliographic databases have potential to improve the application of new knowledge in patient care. This is particularly true for articles about glomerular disease, which are published across multiple disciplines and are often difficult to track down. Our objective was to develop and test search filters for PubMed, Ovid Medline, and Embase that allow physicians to search within a subset of the database to retrieve articles relevant to glomerular disease. Methods We used a diagnostic test assessment framework with development and validation phases. We read a total of 22,992 full text articles for relevance and assigned them to the development or validation set to define the reference standard. We then used combinations of search terms to develop 997,298 unique glomerular disease filters. Outcome measures for each filter included sensitivity, specificity, precision, and accuracy. We selected optimal sensitive and specific search filters for each database and applied them to the validation set to test performance. Results High performance filters achieved at least 93.8% sensitivity and specificity in the development set. Filters optimized for sensitivity reached at least 96.7% sensitivity and filters optimized for specificity reached at least 98.4% specificity. Performance of these filters was consistent in the validation set and similar among all three databases. Conclusions PubMed, Ovid Medline, and Embase can be filtered for articles relevant to glomerular disease in a reliable manner. These filters can now be used to facilitate physician searching.

  8. Water Filters

    Science.gov (United States)

    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.

  9. Development of Front Surface, Spectral Control Filters with Greater Temperature Stability for Thermophotovoltaic Energy Conversion

    Energy Technology Data Exchange (ETDEWEB)

    TD Rahmlow, Jr.; DM DePoy; PM Fourspring; H Ehsani; JE Lazo-Wasem; EJ Gratiix

    2006-10-02

    Spectral control is an important consideration in achieving high conversion efficiency with thermophotovoltaic (TPV) energy conversion systems. TPV modules using front surface filters as the primary spectral control device have demonstrated conversion efficiencies in excess of 20% with power densities in excess of 0.4 W/cm{sup 2}. The front surface filter we are developing is a short pass, long wavelength reflection filter consisting of an interference filter deposited on a plasma filter. The materials used in the interference filter must exhibit high broad band transmission and good film quality and sufficient temperature stability at the operating temperature of the TPV cells and over any potential temperature excursions that may occur. Three high refractive index materials that offer good potential for use in TPV spectral control filters are antimony selenide (Sb{sub 2}Se{sub 3}), antimony sulfide (Sb{sub 2}S{sub 3}), and gallium telluride (GaTe). The highest spectral efficiency has been demonstrated using Sb{sub 2}Se{sub 3}; however this material develops significant near infrared (NIR, 0.72-2.5 {micro}m) absorption at temperatures in excess of 90 C. The other two materials are being developed as high temperature alternatives to Sb{sub 2}Se{sub 3}. TPV filters using GaTe and Sb{sub 2}S{sub 3} have been designed and fabricated, and initial results indicate that GaTe based filters are capable of operation at temperatures of 150 C or greater. Measured performance of TPV filters containing Sb{sub 2}Se{sub 3}, GaTe and Sb{sub 2}S{sub 3} are presented, along with the impact that these have on TPV module performance.

  10. [Development and evaluation of a composite structural filter for removal of arsenic in drinking water].

    Science.gov (United States)

    Zhao, Yuechao; Chen, Yayan; Lin, Shaobin; Wang, Chen; Cao, Yong

    2004-07-01

    To develop a composite structural filter and evaluate its performance on-site for removal of high level arsenic in drinking water. Composite filters were manufactured using iron loaded carbon powder and superfine PE resin as main components. Test water was prepared by spiking arsenic in raw drinking water. The filter application safety and removal effects on arsenic and other parameters were tested. The composite structural filter made of iron loaded carbon powder and superfine PE resin in equal quantity was safe for drinking water treatment and reached a capacity of 2.56mgAs/g for water with arsenic concentration of 0.4mg/L, and improved water turbidity and chemical oxygen demand apparently. The composite filter manufactured using iron loaded carbon powder and superfine PE resin as main components was appropriate for removal of arsenic in rural drinking water with high level of arsenic.

  11. The development of the spatially correlated adjustment wavelet filter for atomic force microscopy data

    Energy Technology Data Exchange (ETDEWEB)

    Sikora, Andrzej, E-mail: sikora@iel.wroc.pl [Electrotechnical Institute, Division of Electrotechnology and Materials Science, M. Skłodowskiej-Curie 55/61, 50-369 Wrocław (Poland); Rodak, Aleksander [Faculty of Electronics, Wrocław University of Technology, Janiszewskiego 11/17, 50-372 Wrocław (Poland); Unold, Olgierd [Institute of Computer Engineering, Control and Robotics, Faculty of Electronics, Wrocław University of Technology, Janiszewskiego 11/17, 50-372 Wrocław (Poland); Klapetek, Petr [Czech Metrology Institute, Okružní 31, 638 00 Brno (Czech Republic)

    2016-12-15

    In this paper a novel approach for the practical utilization of the 2D wavelet filter in terms of the artifacts removal from atomic force microscopy measurements results is presented. The utilization of additional data such as summary photodiode signal map is implemented in terms of the identification of the areas requiring the data processing, filtering settings optimization and the verification of the process performance. Such an approach allows to perform the filtering parameters adjustment by average user, while the straightforward method requires an expertise in this field. The procedure was developed as the function of the Gwyddion software. The examples of filtering the phase imaging and Electrostatic Force Microscopy measurement result are presented. As the wavelet filtering feature may remove a local artifacts, its superior efficiency over similar approach with 2D Fast Fourier Transformate based filter (2D FFT) can be noticed. - Highlights: • A novel approach to 2D wavelet-based filter for atomic force microscopy is shown. • The additional AFM measurement signal is used to adjust the filter. • Efficient removal of the local interference phenomena caused artifacts is presented.

  12. The medline UK filter: development and validation of a geographic search filter to retrieve research about the UK from OVID medline.

    Science.gov (United States)

    Ayiku, Lynda; Levay, Paul; Hudson, Tom; Craven, Jenny; Barrett, Elizabeth; Finnegan, Amy; Adams, Rachel

    2017-07-13

    A validated geographic search filter for the retrieval of research about the United Kingdom (UK) from bibliographic databases had not previously been published. To develop and validate a geographic search filter to retrieve research about the UK from OVID medline with high recall and precision. Three gold standard sets of references were generated using the relative recall method. The sets contained references to studies about the UK which had informed National Institute for Health and Care Excellence (NICE) guidance. The first and second sets were used to develop and refine the medline UK filter. The third set was used to validate the filter. Recall, precision and number-needed-to-read (NNR) were calculated using a case study. The validated medline UK filter demonstrated 87.6% relative recall against the third gold standard set. In the case study, the medline UK filter demonstrated 100% recall, 11.4% precision and a NNR of nine. A validated geographic search filter to retrieve research about the UK with high recall and precision has been developed. The medline UK filter can be applied to systematic literature searches in OVID medline for topics with a UK focus. © 2017 Crown copyright. Health Information and Libraries Journal © 2017 Health Libraries GroupThis article is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland.

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

    Science.gov (United States)

    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.

  14. Development of integrated approaches for hydrological data assimilation through combination of ensemble Kalman filter and particle filter methods

    Science.gov (United States)

    Fan, Y. R.; Huang, G. H.; Baetz, B. W.; Li, Y. P.; Huang, K.; Chen, X.; Gao, M.

    2017-07-01

    This study improved hydrologic data assimilation through integrating the capabilities of particle filter (PF) and ensemble Kalman filter (EnKF) methods, leading to two integrated data assimilation schemes: the coupled EnKF and PF (CEnPF) and parallelized EnKF and PF (PEnPF) approaches. The applicability and usefulness of CEnPF and PEnPF were demonstrated using a conceptual rainfall-runoff model. The performance of two new developed data assimilation methods and traditional EnKF and PF approaches was tested through a synthetic experiment and two real-world cases with one located in the Jing River basin and one located in the Yangtze River basin. The results show that both PEnPF and CEnPF approaches have more opportunities to provide better results for both deterministic and probabilistic predictions than traditional EnKF and PF approaches. Moreover, the computational time of the two integrated methods is manageable. But the proposed PEnPF may need much more time for some large-scale or time-consuming hydrologic models since it generally needs three times of model runs used by EnKF, PF and CEnPF.

  15. Water Filters

    Science.gov (United States)

    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.

  16. Development and characterization of ultra lightweight, highly selective, filter media for oil-water mixtures

    Science.gov (United States)

    Baghernejad, Lida

    Emulsions formed by oil-water mixtures can cause serious issues at different stages of crude oil production, produced water remediation, and oil spills. Efficient, cost-effective processes for separation of oil--water emulsions or dispersions are critical and highly desirable. Filters are among the most common means employed to separate oil-water emulsions into their corresponding components. To conduct single step gravity-based or centrifugal separation of oil--water mixtures into their pure phase, it is essential that the filter be hydrophilic and oleophobic both in air and water. The filter medium should also have high surface porosity, which affects the rate of permeation of one phase. It should be stable at operating temperatures and pressures and be resistant to degradation by chemicals in the feed stream. Favorable oil rejection characteristics, resistance to fouling by organic and inorganic foulants and low cost of production are also important. The goal of this project is to develop ultra-lightweight filters that are durable, highly porous and able to selectively separate oil-water mixtures, from non-woven cellulose based materials by electrospinning. Since electrospinning is a cost-effective, scalable method that can be used to fabricate filters with very thin nanoscale fibers and nano-dimension pores, and cellulose is a very cheap and abundant ingredient, these filters may be considered as novel tools for efficient, cost-effective separation of oil-water emulsions in industry. Currently there is a growing demand for highly porous selective filters for oil-water mixtures in the petroleum industry. These filters are beneficial to both manufacturers and consumers. This research focuses on the development and characterization of the new filter material and evaluation of its suitability for oil-water separation in the field.

  17. The nearby interstellar medium toward α Leo. UV observations and modeling of a warm cloud within hot gas

    Science.gov (United States)

    Gry, Cecile; Jenkins, Edward B.

    2017-02-01

    Aims: Our aim is to characterize the conditions in the nearest interstellar cloud. Methods: We analyze interstellar absorption features in the full UV spectrum of the nearby (d = 24 pc) B8 IVn star α Leo (Regulus). Observations were obtained with STIS at high resolution and high signal-to-noise ratio by the HST ASTRAL Treasury program. We derive column densities for many key atomic species and interpret their partial ionizations. Results: The gas in front of α Leo exhibits two absorption components. The main one is kinematically identified as the local interstellar cloud (LIC) that surrounds the Sun. The second component is shifted by +5.6 km s-1 relative to the main component, in agreement with results for other lines of sight in this region of the sky, and shares its ionization and physical conditions. The excitation of the C II fine-structure levels and the ratio of Mg I to Mg II reveal a temperature T = 6500 (+750, -600) K and electron density n(e) = 0.11 (+0.025, -0.03) cm-3. Our investigation of the ionization balance yields the ion fractions for 10 different atoms and indicates that about 1/3 of the hydrogen atoms are ionized. Metals are significantly depleted onto grains, with sulfur showing [S/H] -0.27. N(H I) = 1.9 (+0.9, -0.6) × 1018 cm-3, which indicates that this partly neutral gas occupies only 2 to 8 parsecs (about 13%) of the space toward the star, with the remaining volume being filled with a hot gas that emits soft X-rays. We do not detect any absorption features from the highly ionized species that could be produced in an interface between the warm medium and the surrounding hot gas, possibly because of non-equilibrium conditions or a particular magnetic field orientation that reduces thermal conduction. Finally, the radial velocity of the LIC agrees with that of the Local Leo Cold Cloud, indicating that they may be physically related.

  18. XMM-Newton and Chandra Observations of the Galaxy Group NGC 5044. 1; Evidence for Limited Multiphase Hot Gas

    Science.gov (United States)

    Buote, David A.; Lewis, Aaron D.; Brighenti, Fabrizio; Mathews, William G.

    2003-01-01

    Using new XMM and Chandra observations, we present an analysis of the temperature structure of the hot gas within a radius of 100 kpc of the bright nearby galaxy group NGC 5044. A spectral deprojection analysis of data extracted from circular annuli reveals that a two-temperature model (2T) of the hot gas is favored over single-phase or cooling flow (M = 4.5 +/- 0.2 solar mass/yr) models within the central approx.30 kpc. Alternatively, the data can be fitted equally well if the temperature within each spherical shell varies continuously from approx.T(sub h) to T(sub c) approx. T(sub h)/2, but no lower. The high spatial resolution of the Chandra data allows us to determine that the temperature excursion T(sub h) approaches T(sub c) required in each shell exceeds the temperature range between the boundaries of the same shell in the best-fitting single-phase model. This is strong evidence for a multiphase gas having a limited temperature range. We do not find any evidence that azimuthal temperature variations within each annulus on the sky can account for the range in temperatures within each shell. We provide a detailed investigation of the systematic errors on the derived spectral models considering the effects of calibration, plasma codes, bandwidth, variable NH, and background rate. We find that the RGS gratings and the EPIC and ACIS CCDs give fully consistent results when the same models are fitted over the same energy ranges for each instrument. The cooler component of the 2T model has a temperature (T(sub c) approx. 0.7 keV) similar to the kinetic temperature of the stars. The hot phase has a temperature (T(sub h) approx. 1.4 keV) characteristic of the virial temperature of the solar mass halo expected in the NGC 5044 group. However, in view of the morphological disturbances and X-ray holes visible in the Chandra image within R approx. equals 10 kpc, bubbles of gas heated to approx.T(sub h) in this region may be formed by intermittent AGN feedback. Some

  19. The Cosmic History of Hot Gas Cooling and Radio AGN Activity in Massive Early-Type Galaxies

    Science.gov (United States)

    Danielson, A. L. R.; Lehmer, B. D.; Alexander, D. M.; Brandt, W. M.; Luo, B.; Miller, N.; Xue, Y. Q.; Stott, J. P.

    2012-01-01

    We study the X-ray properties of 393 optically selected early-type galaxies (ETGs) over the redshift range of z approx equals 0.0-1.2 in the Chandra Deep Fields. To measure the average X-ray properties of the ETG population, we use X-ray stacking analyses with a subset of 158 passive ETGs (148 of which were individually undetected in X-ray). This ETG subset was constructed to span the redshift ranges of z = 0.1-1.2 in the approx equals 4 Ms CDF-S and approx equals 2 Ms CDF-N and z = 0.1-0.6 in the approx equals 250 ks E-CDF-S where the contribution from individually undetected AGNs is expected to be negligible in our stacking. We find that 55 of the ETGs are detected individually in the X-rays, and 12 of these galaxies have properties consistent with being passive hot-gas dominated systems (i.e., systems not dominated by an X-ray bright Active Galactic Nucleus; AGN). On the basis of our analyses, we find little evolution in the mean 0.5-2 keY to B-band luminosity ratio (L(sub x) /L(sub Beta) varies as [1 +z]) since z approx equals 1.2, implying that some heating mechanism prevents the gas from cooling in these systems. We consider that feedback from radio-mode AGN activity could be responsible for heating the gas. We select radio AGNs in the ETG population using their far-infrared/radio flux ratio. Our radio observations allow us to constrain the duty cycle history of radio AGN activity in our ETG sample. We estimate that if scaling relations between radio and mechanical power hold out to z approx equals 1.2 for the ETG population being studied here, the average mechanical power from AGN activity is a factor of approx equals1.4 -- 2.6 times larger than the average radiative cooling power from hot gas over the redshift range z approx equals 0-1.2. The excess of inferred AGN mechanical power from these ETGs is consistent with that found in the local Universe for similar types of galaxies.

  20. Development of nitrocellulose membrane filters impregnated with different biosynthesized silver nanoparticles applied to water purification.

    Science.gov (United States)

    Fernández, Jorge G; Almeida, César A; Fernández-Baldo, Martín A; Felici, Emiliano; Raba, Julio; Sanz, María I

    2016-01-01

    Bactericidal water filters were developed. For this purpose, nitrocellulose membrane filters were impregnated with different biosynthesized silver nanoparticles. Silver nanoparticles (AgNPs) from Aspergillus niger (AgNPs-Asp), Cryptococcus laurentii (AgNPs-Cry) and Rhodotorula glutinis (AgNPs-Rho) were used for impregnating nitrocellulose filters. The bactericidal properties of these nanoparticles against Escherichia coli, Enterococcus faecalis and Pseudomona aeruginosa were successfully demonstrated. The higher antimicrobial effect was observed for AgNPs-Rho. This fact would be related not only to the smallest particles, but also to polysaccharides groups that surrounding these particles. Moreover, in this study, complete inhibition of bacterial growth was observed on nitrocellulose membrane filters impregnated with 1 mg L(-1) of biosynthesized AgNPs. This concentration was able to reduce the bacteria colony count by over 5 orders of magnitude, doing suitable for a water purification device. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Thermal and structural analysis of a filter vessel ceramic tubesheet

    Energy Technology Data Exchange (ETDEWEB)

    Mallett, R.H. [Mallett Technology, Inc., Research Triangle Park, NC (United States); Swindeman, R.W. [Oak Ridge National Lab., TN (United States); Zievers, J.F. [Industrial Filter & Pump Mfg. Co., Cicero, IL (United States)

    1995-08-01

    A ceramic tubesheet assembly for a hot gas filter vessel is analyzed using the finite element method to determine stresses under differential pressure loading. The stresses include local concentration effects. Selection of the stress measures for evaluation of structural integrity is discussed. Specification of stress limits based upon limited data is considered. Stress results from this ongoing design analysis technology project are shown for one design concept.

  2. Design and development of high performance panel air filter with experimental evaluation and analysis of filter media pleats

    Directory of Open Access Journals (Sweden)

    Sagar R. Patil

    2015-11-01

    Full Text Available In automobile vehicles mostly plastic molded panel filters used for the purpose of engine air filtration. Fibrous structured cellulose media were being used with different permeability’s according to requirement of rated air flow rate required for the engine. To optimize the filter pleat design of automotive panel air filter, it is important to study correlation of pressure drop, dust holding capacity & efficiency. The main role of a filter is to provide least pressure drop with high dust holding and efficiency. A channel made for the testing of different pleat designs. This research comprises of experimental design & evaluation of filter element with variable pleat depth and pleat density. This assessment offers the selection of pleat design according to the performance requirements.

  3. Quasi-Optical Filter Development and Characterization for Far-IR Astronomical Applications

    Science.gov (United States)

    Stewart, Kenneth

    Mid-infrared through microwave filters, beamsplitters, and polarizers are a crucial supporting technology for NASA’s space astronomy, astrophysics, and earth science programs. Building upon our successful production of mid-infrared, far-infrared, millimeter, and microwave bandpass and lowpass filters, we propose to investigate aspects of their optical performance that are still not well understood and have yet to be addressed by other researchers. Specifically, we wish to understand and mitigate unexplained high-frequency leaks found to degrade or invalidate spectroscopic data from flight instruments such as Herschel/PACS, SHARC II, GISMO, and ACT, but not predicted by numerical simulations. A complete understanding will improve accuracy and sensitivity, and will enable the mass and volume of cryogenic baffling to be appropriately matched to the physically achievable quasioptical filter response, thereby reducing the cost of future far-infrared missions. The development and experimental validation of this modeling capability will enable optimization of system performance as well as reduce risks to the schedule and end science products for all future space and suborbital missions that use quasioptical filters. The outcome of this work will be critical in achieving the exacting background-limited bolometric detector performance specifications of future far-infrared and submillimeter space instruments. This program will allow us to apply our unique in-house numerical simulation software and develop enhanced layer alignment, filter fabrication, and testing techniques for the first time to address these issues: (1) enhance filter performance, (2) simplify the optical architecture of future instruments by improving our understanding of high-frequency leaks, and (3) produce filters which minimize or eliminate these important effects. With our state-ofthe-art modeling, fabrication, and testing facilities and expertise, established in previous projects, we are uniquely

  4. [Formula: see text]Children's sense of reality: The development of orbitofrontal reality filtering.

    Science.gov (United States)

    Liverani, Maria Chiara; Manuel, Aurélie L; Nahum, Louis; Guardabassi, Veronica; Tomasetto, Carlo; Schnider, Armin

    2017-05-01

    Orbitofrontal reality filtering denotes a memory control mechanism necessary to keep thought and behavior in phase with reality. In adults, it is mediated by the orbitofrontal cortex and subcortical connections and its failure induces reality confusion, confabulations, and disorientation. Here we investigated for the first time the development of this mechanism in 83 children from ages 7 to 11 years and 20 adults. We used an adapted version of a continuous recognition task composed of two runs with the same picture set but arranged in different order. The first run measures storage and recognition capacity (item memory), the second run measures reality filtering. We found that accuracy and reaction times in response to all stimulus types of the task improved in parallel across ages. Importantly, at no age was there a notable performance drop in the second run. This means that reality filtering was already efficacious at age 7 and then steadily improved as item memory became stronger. At the age of 11 years, reality filtering dissociated from item memory, similar to the pattern observed in adults. However, performance in 11-year-olds was still inferior as compared to adults. The study shows that reality filtering develops early in childhood and becomes more efficacious as memory capacity increases. For the time being, it remains unresolved, however, whether this function already depends on the orbitofrontal cortex, as it does in adults, or on different brain structures in the developing brains of children.

  5. Development of a bifunctional filter for prion protein and leukoreduction of red blood cell components.

    Science.gov (United States)

    Yokomizo, Tomo; Kai, Takako; Miura, Morikazu; Ohto, Hitoshi

    2015-02-01

    Leukofiltration of blood components is currently implemented worldwide as a precautionary measure against white blood cell-associated adverse effects and the potential transmission of variant Creutzfeldt-Jakob disease (vCJD). A newly developed bifunctional filter (Sepacell Prima, Asahi Kasei Medical) was assessed for prion removal, leukoreduction (LR), and whether the filter significantly affected red blood cells (RBCs). Sepacell Prima's postfiltration effects on RBCs, including hemolysis, complement activation, and RBC chemistry, were compared with those of a conventional LR filter (Sepacell Pure RC). Prion removal was measured by Western blot after spiking RBCs with microsomal fractions derived from scrapie-infected hamster brain homogenate. Serially diluted exogenous prion solutions (0.05 mL), with or without filtration, were injected intracerebrally into Golden Syrian hamsters. LR efficiency of 4.44 log with the Sepacell Prima was comparable to 4.11 log with the conventional LR filter. There were no significant differences between the two filters in hemoglobin loss, hemolysis, complement activation, and RBC biomarkers. In vitro reduction of exogenously spiked prions by the filter exceeded 3 log. The titer, 6.63 (log ID50 /mL), of prefiltration infectivity of healthy hamsters was reduced to 2.52 (log ID50 /mL) after filtration. The reduction factor was calculated as 4.20 (log ID50 ). With confirmed removal efficacy for exogenous prion protein, this new bifunctional prion and LR filter should reduce the residual risk of vCJD transmission through blood transfusion without adding complexity to component processing. © 2014 AABB.

  6. EVIDENCE FOR THE DIRECT DETECTION OF THE THERMAL SPECTRUM OF THE NON-TRANSITING HOT GAS GIANT HD 88133 b

    KAUST Repository

    Piskorz, Danielle

    2016-11-23

    We target the thermal emission spectrum of the non-transiting gas giant HD 88133 b with high-resolution near-infrared spectroscopy, by treating the planet and its host star as a spectroscopic binary. For sufficiently deep summed flux observations of the star and planet across multiple epochs, it is possible to resolve the signal of the hot gas giant\\'s atmosphere compared to the brighter stellar spectrum, at a level consistent with the aggregate shot noise of the full data set. To do this, we first perform a principal component analysis to remove the contribution of the Earth\\'s atmosphere to the observed spectra. Then, we use a cross-correlation analysis to tease out the spectra of the host star and HD 88133 b to determine its orbit and identify key sources of atmospheric opacity. In total, six epochs of Keck NIRSPEC L-band observations and three epochs of Keck NIRSPEC K-band observations of the HD 88133 system were obtained. Based on an analysis of the maximum likelihood curves calculated from the multi-epoch cross-correlation of the full data set with two atmospheric models, we report the direct detection of the emission spectrum of the non-transiting exoplanet HD 88133 b and measure a radial projection of the Keplerian orbital velocity of 40 +/- 15 km s(-1), a true mass of 1.02(-0.28)(+0.61) M-J, a nearly face-on orbital inclination of 15(-5)(+60), and an atmosphere opacity structure at high dispersion dominated by water vapor. This, combined with 11 years of radial velocity measurements of the system, provides the most up-to-date ephemeris for HD 88133.

  7. THE ORIGIN OF THE HOT GAS IN THE GALACTIC HALO: TESTING GALACTIC FOUNTAIN MODELS' X-RAY EMISSION

    Energy Technology Data Exchange (ETDEWEB)

    Henley, David B.; Shelton, Robin L. [Department of Physics and Astronomy, University of Georgia, Athens, GA 30602 (United States); Kwak, Kyujin [School of Natural Science, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulju-gun, Ulsan 689-798 (Korea, Republic of); Hill, Alex S. [CSIRO Astronomy and Space Science, Marsfield, NSW (Australia); Mac Low, Mordecai-Mark, E-mail: dbh@physast.uga.edu [Department of Astrophysics, American Museum of Natural History, 79th Street at Central Park West, New York, NY 10024 (United States)

    2015-02-20

    We test the X-ray emission predictions of galactic fountain models against XMM-Newton measurements of the emission from the Milky Way's hot halo. These measurements are from 110 sight lines, spanning the full range of Galactic longitudes. We find that a magnetohydrodynamical simulation of a supernova-driven interstellar medium, which features a flow of hot gas from the disk to the halo, reproduces the temperature but significantly underpredicts the 0.5-2.0 keV surface brightness of the halo (by two orders of magnitude, if we compare the median predicted and observed values). This is true for versions of the model with and without an interstellar magnetic field. We consider different reasons for the discrepancy between the model predictions and the observations. We find that taking into account overionization in cooled halo plasma, which could in principle boost the predicted X-ray emission, is unlikely in practice to bring the predictions in line with the observations. We also find that including thermal conduction, which would tend to increase the surface brightnesses of interfaces between hot and cold gas, would not overcome the surface brightness shortfall. However, charge exchange emission from such interfaces, not included in the current model, may be significant. The faintness of the model may also be due to the lack of cosmic ray driving, meaning that the model may underestimate the amount of material transported from the disk to the halo. In addition, an extended hot halo of accreted material may be important, by supplying hot electrons that could boost the emission of the material driven out from the disk. Additional model predictions are needed to test the relative importance of these processes in explaining the observed halo emission.

  8. Continued Development of an Ultra-Narrow Bandpass Filter for Solar Research

    Science.gov (United States)

    Rust, David M.

    1993-01-01

    The objective of work under this task was to develop ultranarrow optical bandpass filters and related technology necessary for construction of a compact solar telescope capable of operating unattended in space. The scientific problems to which such a telescope could be applied include solar seismology, solar activity monitoring, solar irradiance variations, solar magnetic field evolution, and the location of targets for narrow-field specialized telescopes. We have demonstrated a Y-cut lithium-niobate Fabry-Perot etalon. This filter will be used on the Flare Genesis Experiment. We also obtained solar images with a Z-cut etalon. The technical report on etalon filters is attached to this final report. We believe that work under this grant will lead to the commercial availability of a universal optical filter with approximately 0.1 A bandwidth. Progress was made toward making a suitable 1-2 A tunable blocker filter, but it now appears that the best approach is to make a double-cavity etalon that will not require such a narrow blocker. Broader band blockers are commercially available.

  9. Methodology of water quality index (WQI) development for filtrated water using irradiated basic filter elements

    Science.gov (United States)

    Anuar, Nuraslinda; Muhamad Pauzi, Anas; Abu Bakar, Asyraf Arif

    2017-01-01

    Clean water production can be achieved by using common simple water filtration system that consists of an empty bottle and the filter elements such as cotton/coffee filter, sands, and gravels, which can be easily assembled and used. To reduce the time to get an acceptably clean water using the common water filtration, this paper will discuss on a solution to increase the filtration effectiveness of the filter elements by irradiating gossypium (or commonly known as cotton), and silica oxide which is the main composition material for sand and gravel from various scale based on the Wentworth scale. There were few studies regarding gamma and neutron irradiation of silica based materials that proves that gamma and neutron irradiation introduce defects, hence, we expect that it may lead to the formation of micropores and alter the water filtration effectiveness. It was established that higher amount of irradiation results in higher concentration of defects. This paper will firstly review literatures on the effect of gamma and neutron irradiation effect on filter elements such as sands and papers, and then develops a water quality index (WQI) that reflects the water appearance quality of the filtrated water. The WQI focuses on the physical appearance such as smells and color of the filtered water.

  10. Development of sludge filterability test to assess the solids removal potential of a sludge bed

    NARCIS (Netherlands)

    Mahmoud, N.A.; Zandvoort, M.H.; Lier, van J.B.; Zeeman, G.

    2006-01-01

    A qualitative sludge characterisation technique called ¿sludge filterability technique¿ has been developed. This technique enables the determination of the sludge potential for the physical removal of solids, weighing the effect of different process parameters on solids removal and identifying the

  11. Iron oxide impregnated filter paper (Pi test): a review of its development and methodological research

    NARCIS (Netherlands)

    Chardon, W.J.; Menon, R.G.; Chien, S.H.

    1996-01-01

    Iron oxide impregnated filter paper (FeO paper) has been used to study the availability of phosphorus (P) to plants and algae, P desorption kinetics and P dynamics in the field. Since its initial development a number of differences in the method of preparation of the paper and its application have

  12. Development of black coating on filtering media and its effect on ...

    African Journals Online (AJOL)

    Kpong water Treatment plant is one of the two major Water treatment plants supplying the Accra/ Tema Metropolitan areas. The filtering media at Kpong water works has been observed to develop a black coating after three to four years of commissioning. This appearance results in more water than necessary being used for ...

  13. Development of Cryogenic Filter Wheels for the HERSCHEL Photodetector Array Camera & Spectrometer (PACS)

    Science.gov (United States)

    Koerner, Christian; Kampf, Dirk; Poglitsch, Albrecht; Schubert, Josef; Ruppert, U.; Schoele, M.

    2014-01-01

    This paper describes the two PACS Filter Wheels that are direct-drive rotational mechanisms operated at a temperature below 5K inside the PACS focal plane unit of the Herschel Satellite. The purpose of the mechanisms is to switch between filters. The rotation axis is pivoted to the support structure via a slightly preloaded pair of ball bearings and driven by a Cryotorquer. Position sensing is realized by a pair of Hall effect sensors. Powerless positioning at the filter positions is achieved by a magnetic ratchet system. The key technologies are the Cryotorquer design and the magnetic ratchet design in the low temperature range. Furthermore, we will report on lessons learned during the development and qualification of the mechanism and the paint.

  14. Modeling sorbent injection for mercury control in baghouse filters: I--model development and sensitivity analysis.

    Science.gov (United States)

    Flora, Joseph R V; Hargis, Richard A; O'Dowd, William J; Pennline, Henry W; Vidic, Radisav D

    2003-04-01

    A two-stage mathematical model for Hg removal using powdered activated carbon injection upstream of a baghouse filter was developed, with the first stage accounting for removal in the ductwork and the second stage accounting for additional removal caused by the retention of carbon particles on the filter. The model shows that removal in the ductwork is minimal, and the additional carbon detention time from the entrapment of the carbon particles in the fabric filter enhances the Hg removal from the gas phase. A sensitivity analysis on the model shows that Hg removal is dependent on the isotherm parameters, the carbon pore radius and tortuosity, the C/Hg ratio, and the carbon particle radius.

  15. Modeling sorbent injection for mercury control in baghouse filters: I - model development and sensitivity analysis

    Energy Technology Data Exchange (ETDEWEB)

    Joseph R.V. Flora; Richard A. Hargis; William J. O' Dowd; Henry W. Pennline; Radisav D. Vidic [University of South Carolina, Columbia, SC (United States). Department of Civil and Environmental Engineering

    2003-04-01

    A two-stage mathematical model for mercury (Hg) removal using powdered activated carbon injection upstream of a baghouse filter was developed, with the first stage accounting for removal in the ductwork and the second stage accounting for additional removal caused by the retention of carbon particles on the filter. The model shows that removal in the ductwork is minimal, and the additional carbon detention time from the entrapment of the carbon particles in the fabric filter enhances the Hg removal from the gas phase. A sensitivity analysis on the model shows that Hg removal is dependent on the isotherm parameters, the carbon pore radius and tortuosity, the C/Hg ratio, and the carbon particle radius. 23 refs., 8 figs., 1 tab.

  16. Catalytic hot gas cleaning

    Energy Technology Data Exchange (ETDEWEB)

    Simell, P. [VTT Energy, Espoo (Finland)

    1996-12-31

    Gasification gas that contains particulates can be purified from tars and ammonia by using nickel monolith catalysts. Temperatures over 900 deg C are required at 20 bar pressure to avoid deactivation by H{sub 2}S and carbon. Dolomites and limestones are effective tar decomposing catalysts only when calcined. Tar decomposition in gasification conditions can take place by steam or dry (CO{sub 2}) reforming reactions. These reactions follow apparent first order kinetics with respect to hydrocarbons in gasification conditions. (author) (16 refs.)

  17. Hot gas path component

    Energy Technology Data Exchange (ETDEWEB)

    Lacy, Benjamin Paul; Kottilingam, Srikanth Chandrudu; Porter, Christopher Donald; Schick, David Edward

    2017-09-12

    Various embodiments of the disclosure include a turbomachine component. and methods of forming such a component. Some embodiments include a turbomachine component including: a first portion including at least one of a stainless steel or an alloy steel; and a second portion joined with the first portion, the second portion including a nickel alloy including an arced cooling feature extending therethrough, the second portion having a thermal expansion coefficient substantially similar to a thermal expansion coefficient of the first portion, wherein the arced cooling feature is located within the second portion to direct a portion of a coolant to a leakage area of the turbomachine component.

  18. Knowing How Good Our Searches Are: An Approach Derived from Search Filter Development Methodology

    Directory of Open Access Journals (Sweden)

    Sarah Hayman

    2015-12-01

    Full Text Available Objective – Effective literature searching is of paramount importance in supporting evidence based practice, research, and policy. Missed references can have adverse effects on outcomes. This paper reports on the development and evaluation of an online learning resource, designed for librarians and other interested searchers, presenting an evidence based approach to enhancing and testing literature searches. Methods – We developed and evaluated the set of free online learning modules for librarians called Smart Searching, suggesting the use of techniques derived from search filter development undertaken by the CareSearch Palliative Care Knowledge Network and its associated project Flinders Filters. The searching module content has been informed by the processes and principles used in search filter development. The self-paced modules are intended to help librarians and other interested searchers test the effectiveness of their literature searches, provide evidence of search performance that can be used to improve searches, as well as to evaluate and promote searching expertise. Each module covers one of four techniques, or core principles, employed in search filter development: (1 collaboration with subject experts; (2 use of a reference sample set; (3 term identification through frequency analysis; and (4 iterative testing. Evaluation of the resource comprised ongoing monitoring of web analytics to determine factors such as numbers of users and geographic origin; a user survey conducted online elicited qualitative information about the usefulness of the resource. Results – The resource was launched in May 2014. Web analytics show over 6,000 unique users from 101 countries (at 9 August 2015. Responses to the survey (n=50 indicated that 80% would recommend the resource to a colleague. Conclusions – An evidence based approach to searching, derived from search filter development methodology, has been shown to have value as an online learning

  19. Developing a denoising filter for electron microscopy and tomography data in the cloud.

    Science.gov (United States)

    Starosolski, Zbigniew; Szczepanski, Marek; Wahle, Manuel; Rusu, Mirabela; Wriggers, Willy

    2012-09-01

    The low radiation conditions and the predominantly phase-object image formation of cryo-electron microscopy (cryo-EM) result in extremely high noise levels and low contrast in the recorded micrographs. The process of single particle or tomographic 3D reconstruction does not completely eliminate this noise and is even capable of introducing new sources of noise during alignment or when correcting for instrument parameters. The recently developed Digital Paths Supervised Variance (DPSV) denoising filter uses local variance information to control regional noise in a robust and adaptive manner. The performance of the DPSV filter was evaluated in this review qualitatively and quantitatively using simulated and experimental data from cryo-EM and tomography in two and three dimensions. We also assessed the benefit of filtering experimental reconstructions for visualization purposes and for enhancing the accuracy of feature detection. The DPSV filter eliminates high-frequency noise artifacts (density gaps), which would normally preclude the accurate segmentation of tomography reconstructions or the detection of alpha-helices in single-particle reconstructions. This collaborative software development project was carried out entirely by virtual interactions among the authors using publicly available development and file sharing tools.

  20. Design for sustainable development--household drinking water filter for arsenic and pathogen treatment in Nepal.

    Science.gov (United States)

    Ngai, Tommy K K; Shrestha, Roshan R; Dangol, Bipin; Maharjan, Makhan; Murcott, Susan E

    2007-10-01

    In the last 20 years, the widespread adoption of shallow tubewells in Nepal Terai region enabled substantial improvement in access to water, but recent national water quality testing showed that 3% of these sources contain arsenic above the Nepali interim guideline of 50 microg/L, and up to 60% contain unsafe microbial contamination. To combat this crisis, MIT, ENPHO and CAWST together researched, developed and implemented a household water treatment technology by applying an iterative, learning development framework. A pilot study comparing 3 technologies against technical, social, and economic criteria showed that the Kanchan Arsenic Filter (KAF) is the most promising technology for Nepal. A two-year technical and social evaluation of over 1000 KAFs deployed in rural villages of Nepal determined that the KAF typically removes 85-90% arsenic, 90-95% iron, 80-95% turbidity, and 85-99% total coliforms. Then 83% of the households continued to use the filter after 1 year, mainly motivated by the clean appearance, improved taste, and reduced odour of the filtered water, as compared to the original water source. Although over 5,000 filters have been implemented in Nepal by January 2007, further research rooted in sustainable development is necessary to understand the technology diffusion and scale-up process, in order to expand access to safe water in the country and beyond.

  1. Development of adsorptive hybrid filters to enable two-step purification of biologics

    Science.gov (United States)

    Peck, Michael; Voloshin, Alexei M.; Moreno, Angela M.; Tan, Zhijun; Hester, Jonathan; Borys, Michael C.; Li, Zheng Jian

    2017-01-01

    ABSTRACT Recent progress in mammalian cell culture process has resulted in significantly increased product titers, but also a substantial increase in process- and product-related impurities. Due to the diverse physicochemical properties of these impurities, there is constant need for new technologies that offer higher productivity and improved economics without sacrificing the process robustness required to meet final drug substance specifications. Here, we examined the use of new synthetic adsorptive hybrid filters (AHF) modified with the high binding capacity of quaternary amine (Emphaze™ AEX) and salt-tolerant biomimetic (Emphaze™ ST-AEX) ligands for clearance of process-related impurities like host cell protein (HCP), residual DNA, and virus. The potential to remove soluble aggregates was also examined. Our aim was to develop a mechanistic understanding of the interactions governing adsorptive removal of impurities during filtration by evaluating the effect of various filter types, feed streams, and process conditions on impurity removal. The ionic capacity of these filters was measured and correlated with their ability to remove impurities for multiple molecules. The ionic capacity of AHF significantly exceeded that of traditional adsorptive depth filters (ADF) by 40% for the Emphaze™ AEX and by 700% for the Emphaze™ ST-AEX, providing substantially higher reduction of soluble anionic impurities, including DNA, HCPs and model virus. Nevertheless, we determined that ADF with filter aid provided additional hydrophobic functionality that resulted in removal of higher molecular weight species than AHF. Implementing AHF demonstrated improved process-related impurity removal and viral clearance after Protein A chromatography and enabled a two-step purification process. The consequences of enhanced process performance are far reaching because it allows the downstream polishing train to be restructured and simplified, and chromatographic purity standards to be

  2. The separation efficiency of ceramic barrier filters determined at high temperatures by optical particle size and concentration measurement

    Energy Technology Data Exchange (ETDEWEB)

    Hemmer, G.; Umhauer, H.; Kasper, G. [Univ. Karlsruhe, Inst. fuer Mechanische Verfahrenstechnik und Mechanik, Karlsruhe (Germany); Berbner, S. [Freudenberg Nonwovens, Filtration Div., Hopkinsville, KY (United States)

    1999-07-01

    Based on the experiences of earlier investigations a special optical particle counter was developed capable of recording size and quantity (concentration) of the particles directly within a given gas particle stream under the prevailing conditions (true in-situ measurements at high temperatures). In addition to earlier investigations [1], a second type of ceramic filter media with much smaller porosity and a membrane layer on the filtration side was tested. The candles with a length of 1.5 m which are used in industrial applications were mounted in the same hot gas filtration unit already used before. Measurements on the clean gas side at temperatures of up to 1000 C have been conducted using a fraction of quartz particles as test dust. The particle size ranged between 0.3 {mu}m and 10 {mu}m. Filtration velocity (1.5 cm/s) and final pressure drop of dust cake {delta}p (1000 Pa) were kept constant. As a main result the fractional efficiency as function of temperature is discussed and compared with that obtained before for a filter media of type I: The fractional efficiency values of filter type II are at least 100 times higher than that of filter type I. (orig.)

  3. Hot gas in the cold dark matter scenario: X-ray clusters from a high-resolution numerical simulation

    Science.gov (United States)

    Kang, Hyesung; Cen, Renyue; Ostriker, Jeremiah P.; Ryu, Dongsu

    1994-01-01

    A new, three-dimensional, shock-capturing hydrodynamic code is utilized to determine the distribution of hot gas in a standard cold dark matter (CDM) model of the universe. Periodic boundary conditions are assumed: a box with size 85 h(exp -1) Mpc having cell size 0.31 h(exp -1) Mpc is followed in a simulation with 270(exp 3) = 10(exp 7.3) cells. Adopting standard parameters determined from COBE and light-element nucleosynthesis, sigma(sub 8) = 1.05, omega(sub b) = 0.06, and assuming h = 0.5, we find the X-ray-emitting clusters and compute the luminosity function at several wavelengths, the temperature distribution, and estimated sizes, as well as the evolution of these quantities with redshift. We find that most of the total X-ray emissivity in our box originates in a relatively small number of identifiable clusters which occupy approximately 10(exp -3) of the box volume. This standard CDM model, normalized to COBE, produces approximately 5 times too much emission from clusters having L(sub x) is greater than 10(exp 43) ergs/s, a not-unexpected result. If all other parameters were unchanged, we would expect adequate agreement for sigma(sub 8) = 0.6. This provides a new and independent argument for lower small-scale power than standard CDM at the 8 h(exp -1) Mpc scale. The background radiation field at 1 keV due to clusters in this model is approximately one-third of the observed background, which, after correction for numerical effects, again indicates approximately 5 times too much emission and the appropriateness of sigma(sub 8) = 0.6. If we have used the observed ratio of gas to total mass in clusters, rather than basing the mean density on light-element nucleosynthesis, then the computed luminosity of each cluster would have increased still further, by a factor of approximately 10. The number density of clusters increases to z approximately 1, but the luminosity per typical cluster decreases, with the result that evolution in the number density of bright

  4. Development of Filtering Methods for PET Signals Contaminated by RF Pulses for Combined PET-MRI

    Science.gov (United States)

    Huh, Yoonsuk; Choi, Yong; Hong, Key Jo; Hu, Wei; Kang, Jihoon; Jung, Jin Ho; Song, Myung Sung; Park, Hyun-wook; Kim, Byung-Tae

    2013-10-01

    This paper presents the development of filtering methods for positron emission tomography (PET) signals contaminated by radio frequency (RF) pulses for combined PET and clinical 3-T magnetic resonance imaging (MRI). The filtering methods include software, hardware, and hybrid correction methods. In the software correction method, PET signals are assessed, and valid signals are identified based on the characteristics of a typical PET signal using Field-Programmable Gate Array (FPGA)-based programming. The hardware correction method makes use of differential-to-single-ended and low-pass filter circuits for PET analog signals. The hybrid correction method involves the sequential application of both the hardware and software methods. Both valid and contaminated PET signals are measured with an oscilloscope. An evaluation is then made of the performance (energy resolution, photopeak channel, total counts, and coincidence timing resolution) of the PET detector modules with and without various MR sequences (gradient echo, spin echo T1 sequence). For all correction methods, the energy resolution, photopeak position, and coincidence timing resolution with MR sequences are similar (noise signals and reduce count loss while preserving the valid analog signals of MR sequences, is reliable and useful for the development of simultaneous PET-MRI.

  5. Development of a wavy Stark velocity filter for studying interstellar chemistry

    Science.gov (United States)

    Okada, Kunihiro; Takada, Yusuke; Kimura, Naoki; Wada, Michiharu; Schuessler, Hans A.

    2017-08-01

    Cold polar molecules are key to both the understanding of fundamental physics and the characterization of the chemical evolution of interstellar clouds. To facilitate such studies over a wide range of temperatures, we developed a new type of Stark velocity filter for changing the translational and rotational temperatures of velocity-selected polar molecules without changing the output beam position. The translational temperature of guided polar molecules can be significantly varied by exchanging the wavy deflection section with one having a different radius of the curvature and a different deflection angle. Combining in addition a temperature variable gas cell with the wavy Stark velocity filter enables to observe the translational and rotational temperature dependence of the reaction-rate constants of cold ion-polar molecule reactions over the interesting temperature range of 10-100 K.

  6. Development of a wavy Stark velocity filter for studying interstellar chemistry.

    Science.gov (United States)

    Okada, Kunihiro; Takada, Yusuke; Kimura, Naoki; Wada, Michiharu; Schuessler, Hans A

    2017-08-01

    Cold polar molecules are key to both the understanding of fundamental physics and the characterization of the chemical evolution of interstellar clouds. To facilitate such studies over a wide range of temperatures, we developed a new type of Stark velocity filter for changing the translational and rotational temperatures of velocity-selected polar molecules without changing the output beam position. The translational temperature of guided polar molecules can be significantly varied by exchanging the wavy deflection section with one having a different radius of the curvature and a different deflection angle. Combining in addition a temperature variable gas cell with the wavy Stark velocity filter enables to observe the translational and rotational temperature dependence of the reaction-rate constants of cold ion-polar molecule reactions over the interesting temperature range of 10-100 K.

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

    Science.gov (United States)

    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.

  8. Development and preclinical evaluation of a new viewing filter system to control reflection and enhance dye staining during vitrectomy.

    Science.gov (United States)

    Enaida, Hiroshi; Hachisuka, Yoshiyuki; Yoshinaga, Yukiyasu; Ikeda, Yasuhiro; Hisatomi, Toshio; Yoshida, Shigeo; Oshima, Yusuke; Kadonosono, Kazuaki; Ishibashi, Tatsuro

    2013-02-01

    We developed a new artificial image enhancement system and evaluated its usefulness in controlling intraoperative reflection and enhancing of Brilliant Blue G (BBG) staining. The system was composed of three kinds of filters (a polarizing filter, a blue-enhancing filter, and a sharp-cut filter Y) and attached to the inferior surface of the operating microscope. Twenty-seven post-mortem extracted porcine eyes were used for a series of examinations. We performed surgery using the 23G-vitrectomy system with a halogen light and xenon lights and compared the reduction of intraoperative reflection under air condition and visibility and BBG contrast with and without this system. The evaluation of images was calculated in CIE 1976 (L*, a*, b*) color space (CIELAB) carried out by ImageJ software. The transmission of each filter and absorbance of BBG was measured by a spectrophotometer. We measured spectral irradiance at each wavelength about each filter from each light source with a spectroradiometer. Under both light sources, intraoperative reflection was controlled using a polarizing (PL) filter or combination of filters under air condition. Evaluation of the value of L* within the cutter surface was changed by 37.8 % under the halogen light, and 61.6 % (averaged) under the xenon light with inserted filters versus no filter. The BBG intensity difference was obtained with sharp-cut Y filter under both light source and PL with blue enhancing filter under the halogen light using each L*, a*, b* parameter with statistically significant (p system can reduce intraoperative reflections under the air condition and obtain an excellent BBG staining intensity induced by various light sources.

  9. Further development of the cleanable steel HEPA filter, cost/benefit analysis, and comparison with competing technologies

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, W.; Larsen, G.; Lopez, R.; Wilson, K.; Witherell, C.; McGregor, M.

    1997-01-01

    We have made further progress in developing a cleanable steel fiber HEPA filter. We fabricated a pleated cylindrical cartridge using commercially available steel fiber media that is made with 1 {mu}m stainless steel fibers and sintered into a sheet form. Test results at the Department of Energy (DOE) Filter Test Station at Oak Ridge show the prototype filter cartridge has 99.99% efficiency for 0.3 {mu}m dioctyl phthalate (DOP) aerosols and a pressure drop of 1.5 inches. Filter loading and cleaning tests using AC Fine dust showed the filter could be repeatedly cleaned using reverse air pulses. Our analysis of commercially optimized filters suggest that cleanable steel HEPA filters need to be made from steel fibers less than 1 {mu}m, and preferably 0.5 {mu}m, to meet the standard HEPA filter requirements in production units. We have demonstrated that 0.5 {mu}m steel fibers can be produced using the fiber bundling and drawing process. The 0.5 {mu}m steel fibers are then sintered into small filter samples and tested for efficiency and pressure drop. Test results on the sample showed a penetration of 0.0015% at 0.3 {mu}m and a pressure drop of 1.15 inches at 6.9 ft/min (3.5 cm/s) velocity. Based on these results, steel fiber media can easily meet the requirements of 0.03% penetration and 1.0 inch of pressure drop by using less fibers in the media. A cost analysis of the cleanable steel HEPA filter shows that, although the steel HEPA filter costs much more than the standard glass fiber HEPA filter, it has the potential to be very cost effective because of the high disposal costs of contaminated HEPA filters. We estimate that the steel HEPA filter will save an average of $16,000 over its 30 year life. The additional savings from the clean-up costs resulting from ruptured glass HEPA filters during accidents was not included but makes the steel HEPA filter even more cost effective. We also present the results of our evaluation of competing technologies with metallic and

  10. How to identify existing literature on patients' knowledge, views, and values: the development of a validated search filter.

    Science.gov (United States)

    Wessels, Monique; Hielkema, Lian; van der Weijden, Trudy

    2016-10-01

    The research sought to establish validated search filters for retrieval of studies on patients' knowledge and values. Two nonprofit organizations in the Netherlands were studied for guideline development. An existing filter was adapted to three bibliographic interfaces. After defining the scope, a reference database was built for the development of the new filters. The performance of the new filters was validated in different disease categories. Sensitivity, specificity, precision, negative predictive value, and accuracy were (%): 90.5/98/77/99.2/97 (MEDLINE-Ovid), 90.1/98.8/79.3/99.5/98.3 (PubMed), and 93.1/98.4/81.8/99.6/98.7 (Embase). The filters provide pragmatic tools for searching for patients' issues. Further optimization and validation is recommended.

  11. Further development of the cleanable steel HEPA filter, cost/benefit analysis, and comparison with competing technologies

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, W.; Lopez, R.; Wilson, K. [Lawrence Livermore National Lab., CA (United States)] [and others

    1997-08-01

    We have made further progress in developing a cleanable steel fiber HEPA filter. We fabricated a pleated cylindrical cartridge using commercially available steel fiber media that is made with 1 {mu}m stainless steel fibers and sintered into a sheet form. Test results at the Department of Energy (DOE) Filter Test Station at Oak Ridge show the prototype filter cartridge has 99.99% efficiency for 0.3 {mu}m dioctyl phthalate (DOP) aerosols and a pressure drop of 1.5 inches. Filter loading and cleaning tests using AC Fine dust showed the filter could be repeatedly cleaned using reverse air pulses. Our analysis of commercially optimized filters suggest that cleanable steel HEPA filters need to be made from steel fibers less than 1{mu}m, and preferably 0.5 {mu}m, to meet the standard HEPA filter requirements in production units. We have demonstrated that 0.5 {mu}m steel fibers can be produced using the fiber bundling and drawing process. The 0.5 {mu}m steel fibers are then sintered into small filter samples and tested for efficiency and pressure drop. Test results on the sample showed a penetration of 0.0015 % at 0.3 {mu}m and a pressure drop of 1.15 inches at 6.9 ft/min (3.5 cm/s) velocity. Based on these results, steel fiber media can easily meet the requirements of 0.03 % penetration and 1.0 inch of pressure drop by using less fibers in the media. A cost analysis of the cleanable steel HEPA filter shows that, although the steel HEPA filter costs much more than the standard glass fiber HEPA filter, it has the potential to be very cost effective because of the high disposal costs of contaminated HEPA filters. We estimate that the steel HEPA filter will save an average of $16,000 over its 30 year life. The additional savings from the clean-up costs resulting from ruptured glass HEPA filters during accidents was not included but makes the steel HEPA filter even more cost effective. 33 refs., 28 figs., 1 tab.

  12. Development of synthetic and natural mineral based adsorptive and filter media containing cyclodextrin moieties

    Science.gov (United States)

    Andersen, E.; Rácz, I.; Erös, A.; Bánhegyi, Gy; Fenyvesi, É.; Takács, E.

    2013-12-01

    Adsorptive filter media were developed based on UHMWPE (ultra high molecular weight polyethylene), perlite mineral and sol-gel synthesized silica gel as support and various cyclodextrin oligomers and polymers as active adsorbents. Adsorptive capacity was characterized by dye adsorption before and after Soxhlet extraction in water to check the hydrolytic stability of the structures obtained. Morphological and in some cases spectroscopic studies were made to understand the differences in behaviour. At the present stage the development of such structures hardly exceeds the trial and error approach, nevertheless some promising formulations were found.

  13. Development of biomass in a drinking water granular active carbon (GAC) filter.

    Science.gov (United States)

    Velten, Silvana; Boller, Markus; Köster, Oliver; Helbing, Jakob; Weilenmann, Hans-Ulrich; Hammes, Frederik

    2011-12-01

    Indigenous bacteria are essential for the performance of drinking water biofilters, yet this biological component remains poorly characterized. In the present study we followed biofilm formation and development in a granular activated carbon (GAC) filter on pilot-scale during the first six months of operation. GAC particles were sampled from four different depths (10, 45, 80 and 115 cm) and attached biomass was measured with adenosine tri-phosphate (ATP) analysis. The attached biomass accumulated rapidly on the GAC particles throughout all levels in the filter during the first 90 days of operation and maintained a steady state afterward. Vertical gradients of biomass density and growth rates were observed during start-up and also in steady state. During steady state, biomass concentrations ranged between 0.8-1.83 x 10(-6) g ATP/g GAC in the filter, and 22% of the influent dissolved organic carbon (DOC) was removed. Concomitant biomass production was about 1.8 × 10(12) cells/m(2)h, which represents a yield of 1.26 × 10(6) cells/μg. The bacteria assimilated only about 3% of the removed carbon as biomass. At one point during the operational period, a natural 5-fold increase in the influent phytoplankton concentration occurred. As a result, influent assimilable organic carbon concentrations increased and suspended bacteria in the filter effluent increased 3-fold as the direct consequence of increased growth in the biofilter. This study shows that the combination of different analytical methods allows detailed quantification of the microbiological activity in drinking water biofilters. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Photographic filters

    Science.gov (United States)

    Rodigues, Jose Eduardo; Santosdealmeida, Wagner

    1987-12-01

    Some of the main aspects related to photographic filters are examined and prepared as a reference for researchers and students of remote sensing. A large range of information about the filters including their basic fundamentals, classification, and main types is presented. The theme cannot be exhausted in this or any other individual publication because of its great complexity, profound theoretical publication, and dynmaic technological development. The subject does not deal only with filter applications in remote sensing. As much as possible, additional information about the utilization of these products in other professional areas, as pictorial photography, photographic processing, and optical engineering, were included.

  15. Development of a hot heat exchanger and a cleaning system for a 35 kW hermetic four cylinder Stirling engine for solid biomass fuels

    DEFF Research Database (Denmark)

    Carlsen, Henrik; Marinitsch, Gerald; Schöch, Martin

    2005-01-01

    been operated for more than 9,000 hours. Operating experiences gained from these plants formed the basis for the further development of this technology. The experiences showed that the efficiency of the Stirling hot gas heat exchanger and of the hot gas heat exchanger cleaning system have to be further...... optimised. Within the scope of a RD&D project, a new hot gas heat exchanger and a new cleaning system have been developed and optimised in cooperation of the AUSTRIAN BIOENERGY CENTRE GmbH, the Technical University of Denmark, MAWERA Holzfeuerungsanlagen GmbH, Austria, and BIOS BIOENERGIESYSTEME Gmb......H, Austria. The new design of the Stirling hot gas heat exchanger has been developed in order to optimise the performance of the engine and simplify the geometry. In this respect, an equal distribution of the heat transfer across each tube in the hot gas heat exchanger, the reduction of the internal Helium...

  16. Water Usage and Availability in Bongo's Communities: Research Leading to the Development of an Indigenous Fluoride Filter

    Science.gov (United States)

    Friscia, J. M.; Epstein, B.; Cumberbatch, T.; Okuneff, A.

    2010-12-01

    Over the course of a six-week period in both 2009 and 2010, an investigation into the collection and usage of water was undertaken in the Bongo District of Ghana. The outcome of this research was to provide data for the design of a defluoridation filter for the groundwater that could be used either in the household or at the borehole. This filter would use laterite as the filter medium and would prevent the development of dental fluorosis, which is common in the District. In 2009, the focus was on denser, more centrally located communities, while the research in 2010 focused on communities in which people live further from water sources. The localities studied were in Namoo, Kuyelingo, Bongo Central, and Kadare. After an analysis of data collected in 2009 and a preliminary review of data collected in 2010, it has been determined that the different localities have different requirements for a filter design. Denser communities, including parts of Namoo, Kuyelingo, and Bongo Central, would benefit most from a filter installed directly at the borehole. This filter would not process all the water fetched, since less than half the water collected is ingested. In more remote communities, such as parts of Kuyelingo near the Vea Dam and Kadare, a household filter would be ideal. In these communities, when people live far from the borehole, they seek other sources, including river water, wells, rainwater, and dam water. Many of these sources are unsafe to drink without proper treatment. Therefore, a household filter that can filter the fluoride from borehole water (when the household does indeed fetch from the pump) and can filter bacteria and viruses from the other water sources would be most appropriate. The results from the water survey provide an overview of the water collection rate throughout the day, distance the water is carried to the individual households, and breakdown of water usage within the household - in both dense and remote communities. Child with Dental

  17. Development and Performance Evaluation of a Ceramic Filter for Point-of-Use Water Purification

    National Research Council Canada - National Science Library

    Bukola Olalekan Bolaji; Olugbenga Oluseyi Akande

    2013-01-01

    In this work, a ceramic filter for point-of-use water purification was designed, fabricated and tested to evaluate its performance in filtering water to the World Health Organisation (WHO) standards...

  18. Breakdown electric fields in dissociated hot gas mixtures of sulfur hexafluoride including teflon: Calculations with experimental validations and utilization in fluid dynamics arc simulations

    Science.gov (United States)

    Yousfi, M.; Merbahi, N.; Reichert, F.; Petchanka, A.

    2017-03-01

    Measurements of breakdown voltage Vb, gas temperature Tg, and density N and the associated critical electric field Ecr/N are performed in hot dissociated SF6 highly diluted in argon and in hot dissociated SF6 mixed with PTFE (Polytetrafluoroethylene or C2F4) also highly diluted in argon. Gases are heated using a microwave source and optical emission spectroscopy is used for measurements of Tg and N while Vb is measured from a specific inter-electrode arrangement placed inside of the cell of the hot gas conditioning. The experimental Ecr/N data in the numerous considered cases of gas temperatures and compositions have been used to evaluate and validate the sets of the collision cross sections of the 11 species involved in hot dissociated SF6 (i.e., SF6, SF5, SF4, S2F2, SF3, SF2, SF, S2, F2, F, and S), the 13 additional species involved either in hot C2F4 or CF4 (C2F6, C2F4, C2F2, CF4, CF3, CF2, CF, F2, F and carbon species as C, C2, C3, C4) and also the 2 further species (CS and CS2) present only in the considered mixtures SF6 + C2F4. The fitted sets of collision cross sections of all these 26 species are then used without argon dilution in hot SF6 and hot SF6 + C2F4 mixtures to calculate and to analyze the Ecr/N data obtained for a wide range of gas temperature (up to 4000 K) and gas pressure (8 bar and more) using a rigorous multi-term solution of the Boltzmann equation for electron energy distribution function and standard calculations of hot gas composition for the species proportions. Such Ecr/N data have been then successfully used to evaluate from a Computational Fluid Dynamics model the switching capacity at terminal fault from a coupled simulation of the electrostatic field and the hot gas flow after current zero.

  19. [Influence of wearing long wavelength filter glasses on refractive development of children's hyperopia].

    Science.gov (United States)

    Huang, J; Yu, Z Q; Chu, R Y; Qian, Y S; Xu, Y; Wang, X Q

    2017-01-11

    Objective: To investigate the effect of wearing long wavelength filter glasses on refractive development of children's hyperopia. Methods: Case control study. Seventeen 5-7 years' old children with high hyperopia from optometry clinic of Eye and ENT Hospital Affiliated to Fudan University were enrolled in this research. The experiment design was self-control between right and left eye, 3 children were lost during two years' period of observation, all the children's hyperopic refraction were more than +6.00 D, cycloplegic by 1% atropine. All the children were required to wear long wavelength filter glasses for 6 hours after waking up, the rest of the time with the conventional glasses. Refraction, axis and red/green match point were tested before the intervention and 3, 6, 12, 18, 24 months, after the intervention. Results: After two years' intervention, hyperopia decreased, eye axis increased, the best corrected visual acuity increased both in experimental eyes and control eyes, but there were no statistically significant difference between the two groups at each time point. All children were with normal color vision, compared to the long-wavelength light, the hyperopic eyes were more sensitive to middle-wavelength light, no significant difference was found between two groups, red/green match points were 42.802±1.216 and 42.889±1.560 respectively. After wearing long wavelength filter, red/green match point were significant decreased in the experimental group in 6 months and 12 months time points (6 months: 0.995±0. 543 vs. 0.104±0.143, t=3.04, P=0.005, 12 months: 1.096±0.392 vs. 0.17±0.248, t=2.725, P=0.008). The experiment eyes were more sensitive to long-wavelength light than the control eyes. But in later time, there was no significant difference between two groups. Conclusion: Wearing long wavelength filter glasses two years has no effect on refractive development on children with high hyperopia, but it can cause short-term chromatic adaptation, making

  20. Hybrid Adaptive Filter development for the minimisation of transient fluctuations superimposed on electrotelluric field recordings mainly by magnetic storms

    Directory of Open Access Journals (Sweden)

    A. Konstantaras

    2006-01-01

    Full Text Available The method of Hybrid Adaptive Filtering (HAF aims to recover the recorded electric field signals from anomalies of magnetotelluric origin induced mainly by magnetic storms. An adaptive filter incorporating neuro-fuzzy technology has been developed to remove any significant distortions from the equivalent magnetic field signal, as retrieved from the original electric field signal by reversing the magnetotelluric method. Testing with further unseen data verifies the reliability of the model and demonstrates the effectiveness of the HAF method.

  1. Hybrid Adaptive Filter development for the minimisation of transient fluctuations superimposed on electrotelluric field recordings mainly by magnetic storms

    OpenAIRE

    Konstantaras, A.; Varley, M. R.; Vallianatos, F.; Makris, J. P.; Collins, G.; Holifield, P.

    2006-01-01

    The method of Hybrid Adaptive Filtering (HAF) aims to recover the recorded electric field signals from anomalies of magnetotelluric origin induced mainly by magnetic storms. An adaptive filter incorporating neuro-fuzzy technology has been developed to remove any significant distortions from the equivalent magnetic field signal, as retrieved from the original electric field signal by reversing the magnetotelluric method. Testing with further unseen data verifies the reliability of the model an...

  2. Hybrid Adaptive Filter development for the minimisation of transient fluctuations superimposed on electrotelluric field recordings mainly by magnetic storms

    OpenAIRE

    A. Konstantaras; M. R. Varley; F. Vallianatos; J. P. Makris; G. Collins; P.  Holifield

    2006-01-01

    International audience; The method of Hybrid Adaptive Filtering (HAF) aims to recover the recorded electric field signals from anomalies of magnetotelluric origin induced mainly by magnetic storms. An adaptive filter incorporating neuro-fuzzy technology has been developed to remove any significant distortions from the equivalent magnetic field signal, as retrieved from the original electric field signal by reversing the magnetotelluric method. Testing with further unseen data verifies the rel...

  3. Hybrid Adaptive Filter development for the minimisation of transient fluctuations superimposed on electrotelluric field recordings mainly by magnetic storms

    Science.gov (United States)

    Konstantaras, A.; Varley, M. R.; Vallianatos, F.; Makris, J. P.; Collins, G.; Holifield, P.

    2006-10-01

    The method of Hybrid Adaptive Filtering (HAF) aims to recover the recorded electric field signals from anomalies of magnetotelluric origin induced mainly by magnetic storms. An adaptive filter incorporating neuro-fuzzy technology has been developed to remove any significant distortions from the equivalent magnetic field signal, as retrieved from the original electric field signal by reversing the magnetotelluric method. Testing with further unseen data verifies the reliability of the model and demonstrates the effectiveness of the HAF method.

  4. Development of Wien filter for small ion gun of surface analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bahng, Jungbae [Department of Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Busan Center, Korea Basic Science Institute, Busan 609-735 (Korea, Republic of); Hong, Jonggi; Choi, Myoung Choul; Won, Mi-Sook; Lee, Byoung-Seob, E-mail: bslee@kbsi.re.kr [Busan Center, Korea Basic Science Institute, Busan 609-735 (Korea, Republic of)

    2016-02-15

    The gas cluster ion beam (GCIB) and liquid metal ion beam have been studied in the context of ion beam usage for analytical equipment in applications such as X-ray photoelectron spectroscopy and secondary ion mass spectroscopy (SIMS). In particular, small ion sources are used for the secondary ion generation and ion etching. To set the context to this study, the SIMS project has been launched to develop ion-gun based analytical equipment for the Korea Basic Science Institute. The objective of the first stage of the project is the generation of argon beams with a GCIB system [A. Kirkpatrick, Nucl. Instrum. Methods Phys. Res., Sect. B 206, 830–837 (2003)] that consists of a nozzle, skimmer, ionizer, acceleration tube, separation system, transport system, and target. The Wien filter directs the selected cluster beam to the target system by exploiting the velocity difference of the generated particles from GCIB. In this paper, we present the theoretical modeling and three-dimensional electromagnetic analysis of the Wien filter, which can separate Ar{sup +}{sub 2500} clusters from Ar{sup +}{sub 2400} to Ar{sup +}{sub 2600} clusters with a 1-mm collimator.

  5. Developing diagnostics for input-output systems: the effects of certain linear and nonlinear filters on the correlation integral

    Directory of Open Access Journals (Sweden)

    D. Vassiliadis

    1994-01-01

    Full Text Available Input-output systems are characterized by applying time series analysis techniques developed for autonomous systems to the input and the output time series separately and using the results as nonlinear statistics of the time series distributions. Two examples are presented using the correlation integral as a nonlinear statistic: the first one examines the change in the statistic when several sample input time series are passed through a nonlinear filter. The rectifier is chosen as the filter because it models, at first approximation, the effect of dayside magnetospheric reconnection to the interplanetary magnetic field and solar wind input. The changes in the correlation integral are used to characterize the filter response. A second example compares a linear filter of the rectified solar wind input to the observed auroral geomagnetic activity in terms of their correlation integrals. Implications for models of the solar wind-magneto- sphere coupling are discussed.

  6. High-performance ceramic filters for energy engineering. Final report; Filter aus Hochleistungskeramik fuer die Energietechnik. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Westerheide, R. [Fraunhofer-Institut fuer Werkstoffmechanik (IWM), Freiburg im Breisgau (Germany); Adler, J. [Fraunhofer-Institut fuer Keramische Technologien und Sinterwerkstoffe (IKTS), Dresden (Germany); Buhl, H. [ESK-SIC GmbH, Frechen-Grefrath (Germany); Fister, D. [H.C. Starck GmbH, Laufenburg (Germany); Krein, J. [LLB Lurgi Lentjes Energietechnik GmbH, Frankfurt (Germany); Voelker, W. [Annawerk GmbH, Roedental (Germany); Walch, A. [eds.] [USF Schumacher Umwelt- und Trenntechnik GmbH, Crailsheim (Germany)

    1999-09-30

    The hot gas particulate removal of many advanced coal fired power generation technologies works at temperatures above 800 C. The filter elements for these applications are often based on ceramic materials, e.g. silicon carbide. However, the mostly clay bonded silicon carbide is subject to creep and oxidation due to probable changes of the binder phase. In this work the development of new ceramic filter materials based on silicon carbide and alumina is described. The goal of the development was to increase the potential application temperature. To obtain the goal, the work was performed together with ceramic powder manufacturers, developers of ceramic materials and components as well as with companies who operate test facilities. Different routes were chosen to increase the high temperature resistance in consideration of corrosion resistance, fracture strength and pressure loss of the filter materials. One of these routes was the optimization of the binder phase of the silicon carbide materials. Other routes were concentrated on the base material and the investigation of other possibilities for the silicon carbide bonding, i.e. a recrystallization process of SiC (RSiC) or a self bonding of granulated small grained silicon carbide powder. Additionally filter materials based on alumina were developed. The report covers these material development oriented topics as well as the additional work in materials reliability, coating development and modeling of microstructure. (orig.) [German] In der Kombikraftwerkstechnik wird insbesondere bei Kohlefeuerung die Heissgasreinigung oft bei Temperaturen ueber 800 C eingesetzt. Die Filterelemente fuer diese Anwendungen bestehen oft aus keramischen Materialien. Das haeufig eingesetzte tongebundene Siliciumcarbid unterliegt jedoch besonders aufgrund der Beschaffenheit der Bindephase Kriech- und Oxidationsschaedigungen. In diesem Bericht wird die Entwicklung von neuen keramischen Filtermaterialien, die auf Siliciumcarbid oder

  7. Development of a heart failure filter for Medline: an objective approach using evidence-based clinical practice guidelines as an alternative to hand searching.

    Science.gov (United States)

    Damarell, Raechel A; Tieman, Jennifer; Sladek, Ruth M; Davidson, Patricia M

    2011-01-28

    Heart failure is a highly debilitating syndrome with a poor prognosis primarily affecting the elderly. Clinicians wanting timely access to heart failure evidence to provide optimal patient care can face many challenges in locating this evidence. This study developed and validated a search filter of high clinical utility for the retrieval of heart failure articles in OvidSP Medline. A Clinical Advisory Group was established to advise study investigators. The study set of 876 relevant articles from four heart failure clinical practice guidelines was divided into three datasets: a Term Identification Set, a Filter Development Set, and a Filter Validation Set. A further validation set (the Cochrane Validation Set) was formed using studies included in Cochrane heart failure systematic reviews. Candidate search terms were identified via word frequency analysis. The filter was developed by creating combinations of terms and recording their performance in retrieving items from the Filter Development Set. The filter's recall was then validated in both the Filter Validation Set and the Cochrane Validation Set. A precision estimate was obtained post-hoc by running the filter in Medline and screening the first 200 retrievals for relevance to heart failure. The four-term filter achieved a recall of 96.9% in the Filter Development Set; 98.2% in the Filter Validation Set; and 97.8% in the Cochrane Validation Set. Of the first 200 references retrieved by the filter when run in Medline, 150 were deemed relevant and 50 irrelevant. The post-hoc precision estimate was therefore 75%. This study describes an objective method for developing a validated heart failure filter of high recall performance and then testing its precision post-hoc. Clinical practice guidelines were found to be a feasible alternative to hand searching in creating a gold standard for filter development. Guidelines may be especially appropriate given their clinical utility. A validated heart failure filter is now

  8. Development and evaluation of a prototype non-woven fabric filter for purification of malaria-infected blood

    Directory of Open Access Journals (Sweden)

    Tao Zhi-Yong

    2011-08-01

    Full Text Available Abstract Background Many malaria-related studies depend on infected red blood cells (iRBCs as fundamental material; however, infected blood samples from human or animal models include leukocytes (white blood cells or WBCs, especially difficult to separate from iRBCs in cases involving Plasmodium vivax. These host WBCs are a source of contamination in biology, immunology and molecular biology studies, requiring their removal. Non-woven fabric (NWF has the ability to adsorb leukocytes and is already used as filtration material to deplete WBCs for blood transfusion and surgery. The present study describes the development and evaluation of a prototype NWF filter designed for purifying iRBCs from malaria-infected blood. Methods Blood samples of P. vivax patients were processed separately by NWF filter and CF11 column methods. WBCs and RBCs were counted, parasite density, morphology and developing stage was checked by microscopy, and compared before and after treatment. The viability of filtrated P. vivax parasites was examined by in vitro short-term cultivation. Results A total of 15 P. vivax-infected blood samples were treated by both NWF filter and CF11 methods. The WBC removal rate of the NWF filter method was 99.03%, significantly higher than the CF11 methods (98.41%, P P in vitro short-term culture results showed that after filter treatment, P. vivax parasite could develop as normal as CF11 method, and no obvious density, developing stage difference were fund between two methods. Conclusions NWF filter filtration removed most leukocytes from malaria-infected blood, and the recovery rate of RBCs was higher than with CF11 column method. Filtrated P. vivax parasites were morphologically normal, viable, and suitable for short-term in vitro culture. NWF filter filtration is simple, fast and robust, and is ideal for purification of malaria-infected blood.

  9. Development and evaluation of antimicrobial activated carbon fiber filters using Sophora flavescens nanoparticles.

    Science.gov (United States)

    Sim, Kyoung Mi; Kim, Kyung Hwan; Hwang, Gi Byoung; Seo, SungChul; Bae, Gwi-Nam; Jung, Jae Hee

    2014-09-15

    Activated carbon fiber (ACF) filters have a wide range of applications, including air purification, dehumidification, and water purification, due to their large specific surface area, high adsorption capacity and rate, and specific surface reactivity. However, when airborne microorganisms such as bacteria and fungi adhere to the carbon substrate, ACF filters can become a source of microbial contamination, and their filter efficacy declines. Antimicrobial treatments are a promising means of preventing ACF bio-contamination. In this study, we demonstrate the use of Sophora flavescens in antimicrobial nanoparticles coated onto ACF filters. The particles were prepared using an aerosol process consisting of nebulization-thermal drying and particle deposition. The extract from S. flavescens is an effective, natural antimicrobial agent that exhibits antibacterial activity against various pathogens. The efficiency of Staphylococcus epidermidis inactivation increased with the concentration of S. flavescens nanoparticles in the ACF filter coating. The gas adsorption efficiency of the coated antimicrobial ACF filters was also evaluated using toluene. The toluene-removal capacity of the ACF filters remained unchanged while the antimicrobial activity was over 90% for some nanoparticle concentrations. Our results provide a scientific basis for controlling both bioaerosol and gaseous pollutants using antimicrobial ACF filters coated with S. flavescens nanoparticles. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Development and evaluation of a plant-based air filter system for ...

    African Journals Online (AJOL)

    Y. Choi

    2013-04-17

    Apr 17, 2013 ... We investigated a novel plant-based air filter system for bacterial growth control. The volatile ... The results show that the air filter system used in this ..... improving their air pollutant-removing activity for indoor air quality control. ACKNOWLEDGEMENT. This study was supported by the Korea Ministry of Envi-.

  11. Subpilot scale gasifier evaluation of ceramic cross flow filter. Final report, February 1, 1988--December 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Lippert, T.E.; Alvin, M.A.; Smeltzer, E.E.; Bachovchin, D.M.; Meyer, J.H.

    1993-08-01

    The operating characteristics, performance and durability of a hot gas cross flow filter system were evaluated at the Texaco 15 tpd, entrained-bed gasifier pilot plant facility that is located at their Montebello Research Facilities (MRL) in California. A candle filter unit was also tested for comparative purposes. A wide range of operating test conditions were experienced. This report summarizes the results of eleven different test runs that occurred from April 1989 through August 1992. Differences between filter operation on the entrained gasifier and prior experience on fluid bed combustion are discussed.

  12. Enhanced Bank of Kalman Filters Developed and Demonstrated for In-Flight Aircraft Engine Sensor Fault Diagnostics

    Science.gov (United States)

    Kobayashi, Takahisa; Simon, Donald L.

    2005-01-01

    In-flight sensor fault detection and isolation (FDI) is critical to maintaining reliable engine operation during flight. The aircraft engine control system, which computes control commands on the basis of sensor measurements, operates the propulsion systems at the demanded conditions. Any undetected sensor faults, therefore, may cause the control system to drive the engine into an undesirable operating condition. It is critical to detect and isolate failed sensors as soon as possible so that such scenarios can be avoided. A challenging issue in developing reliable sensor FDI systems is to make them robust to changes in engine operating characteristics due to degradation with usage and other faults that can occur during flight. A sensor FDI system that cannot appropriately account for such scenarios may result in false alarms, missed detections, or misclassifications when such faults do occur. To address this issue, an enhanced bank of Kalman filters was developed, and its performance and robustness were demonstrated in a simulation environment. The bank of filters is composed of m + 1 Kalman filters, where m is the number of sensors being used by the control system and, thus, in need of monitoring. Each Kalman filter is designed on the basis of a unique fault hypothesis so that it will be able to maintain its performance if a particular fault scenario, hypothesized by that particular filter, takes place.

  13. Development and testing of a medline search filter for identifying patient and public involvement in health research.

    Science.gov (United States)

    Rogers, Morwenna; Bethel, Alison; Boddy, Kate

    2017-06-01

    Research involving the public as partners often proves difficult to locate due to the variations in terms used to describe public involvement, and inability of medical databases to index this concept effectively. To design a search filter to identify literature where patient and public involvement (PPI) was used in health research. A reference standard of 172 PPI papers was formed. The references were divided into a development set and a test set. Search terms were identified from common words, phrases and synonyms in the development set. These terms were combined as a search strategy for medline via OvidSP, which was then tested for sensitivity against the test set. The resultant search filter was then assessed for sensitivity, specificity and precision using a previously published systematic review. The search filter was found to be highly sensitive 98.5% in initial testing. When tested against results generated by a 'real-life' systematic review, the filter had a specificity of 81%. However, sensitivity dropped to 58%. Adjustments to the population group of terms increased the sensitivity to 73%. The PPI filter designed for medline via OvidSP could aid information specialists and researchers trying to find literature specific to PPI. © 2016 Health Libraries Group.

  14. Development of the Kinematic Global Positioning System Precise Point Positioning Method Using 3-Pass Filter

    Directory of Open Access Journals (Sweden)

    Byung-Kyu Choi

    2012-09-01

    Full Text Available Kinematic global positioning system precise point positioning (GPS PPP technology is widely used to the several area such as monitoring of crustal movement and precise orbit determination (POD using the dual-frequency GPS observations. In this study we developed a kinematic PPP technology and applied 3-pass (forward/backward/forward filter for the stabilization of the initial state of the parameters to be estimated. For verification of results, we obtained GPS data sets from six international GPS reference stations (ALGO, AMC2, BJFS, GRAZ, IENG and TSKB and processed in daily basis by using the developed software. As a result, the mean position errors by kinematic PPP showed 0.51 cm in the east-west direction, 0.31 cm in the north-south direction and 1.02 cm in the up-down direction. The root mean square values produced from them were 1.59 cm for the east-west component, 1.26 cm for the south-west component and 2.95 cm for the up-down component.

  15. Development and stability studies of sunscreen cream formulations containing three photo-protective filters

    Directory of Open Access Journals (Sweden)

    Slim Smaoui

    2017-02-01

    Full Text Available The present study aimed to formulate and subsequently evaluate sunscreen cream (W/O/W emulsion containing three photo-protective filters: benzophenone-3, ethylhexyl methoxycinnamate and titanium dioxide at different percentages. Formulations were stored at 8, 25 and 40 °C for four weeks to investigate their stability. Color, centrifugation, liquefaction, phase separation, pH and Sun Protection Factor (SPF of sunscreen cream formulations were determined. The microbiological stability of the creams was also evaluated and the organoleptic quality was carried out for 28 days. Interestingly, the combination of 7% Benzophenone-3, 7% Ethylhexyl methoxycinnamate and 6% Titanium dioxide preserved physicochemical properties of the product and was efficient against the development of different spoilage microorganisms as well as aerobic plate counts, Pseudomonas aeruginosa, Staphylococcus aureus, and yeast and mold counts. Furthermore, a good stability was observed for all formulations throughout the experimental period. The newly formulated sunscreen cream was proved to exhibit a number of promising properties and attributes that might open new opportunities for the development of more efficient, safe, and cost-effective skin-care, cosmetic, and pharmaceutical products.

  16. Development of simple band-spectral pyranometer and quantum meter using photovoltaic cells and bandpass filters

    Energy Technology Data Exchange (ETDEWEB)

    Bilguun, Amarsaikhan, E-mail: bilguun@pes.ee.tut.ac.jp; Nakaso, Tetsushi; Harigai, Toru; Suda, Yoshiyuki; Takikawa, Hirofumi, E-mail: takikawa@ee.tut.ac.jp [Toyohashi University of Technology, 1-1 Habarigaoka, Tempaku, Toyohashi 441-8580 (Japan); Tanoue, Hideto [Kitakyushu National College of Technology, 5-20-1, Kokuraminami, Kitakyushu, Fukuoka 802-0985 (Japan)

    2016-02-01

    In recent years, greenhouse automatic-control, based on the measurement of solar irradiance, has been attracting attention. This control is an effective method for improving crop production. In the agricultural field, it is necessary to measure Photon Flux Density (PFD), which is an important parameter in the promotion of plant growth. In particular, the PFD of Photosynthetically Active Radiation (PAR, 400-700 nm) and Plant Biologically Active Radiation (PBAR, 300-800 nm) have been discussed in agricultural plant science. The commercial quantum meter (QM, PAR meter) can only measure Photosynthetically Photon Flux Density (PPFD) which is the integrated PFD quantity on the PAR wavelength. In this research, a band-spectral pyranometer or quantum meter using PVs with optical bandpass filters for dividing the PBAR wavelength into 100 nm bands (five independent channels) was developed. Before field testing, calibration of the instruments was carried out using a solar simulator. Next, a field test was conducted in three differing weather conditions such as clear, partly cloudy and cloudy skies. As a result, it was found that the response rate of the developed pyranometer was faster by four seconds compared with the response rate of the commercial pyranometer. Moreover, the outputs of each channel in the developed pyranometer were very similar to the integrated outputs of the commercial spectroradiometer. It was confirmed that the solar irradiance could be measured in each band separately using the developed band-spectral pyranometer. It was indicated that the developed band-spectral pyranometer could also be used as a PV band-spectral quantum meter which is obtained by converting the band irradiance into band PFD.

  17. Development and flight tests of a Kalman filter for navigation during terminal area and landing operations

    Science.gov (United States)

    Schmidt, S. F.; Flanagan, P. F.; Sorenson, J. A.

    1978-01-01

    A Kalman filter for aircraft terminal area and landing navigation was implemented and flight tested in the NASA Ames STOLAND avionics computer onboard a Twin Otter aircraft. This system combines navaid measurements from TACAN, MODILS, air data, radar altimeter sensors along with measurements from strap-down accelerometer and attitude angle sensors. The flight test results demonstrate that the Kalman filter provides improved estimates of the aircraft position and velocity as compared with estimates from the more standard complementary filter. The onboard computer implementation requirements to achieve this improved performance are discussed.

  18. Development and evaluation of a prototype non-woven fabric filter for purification of malaria-infected blood.

    Science.gov (United States)

    Tao, Zhi-Yong; Xia, Hui; Cao, Jun; Gao, Qi

    2011-08-25

    Many malaria-related studies depend on infected red blood cells (iRBCs) as fundamental material; however, infected blood samples from human or animal models include leukocytes (white blood cells or WBCs), especially difficult to separate from iRBCs in cases involving Plasmodium vivax. These host WBCs are a source of contamination in biology, immunology and molecular biology studies, requiring their removal. Non-woven fabric (NWF) has the ability to adsorb leukocytes and is already used as filtration material to deplete WBCs for blood transfusion and surgery. The present study describes the development and evaluation of a prototype NWF filter designed for purifying iRBCs from malaria-infected blood. Blood samples of P. vivax patients were processed separately by NWF filter and CF11 column methods. WBCs and RBCs were counted, parasite density, morphology and developing stage was checked by microscopy, and compared before and after treatment. The viability of filtrated P. vivax parasites was examined by in vitro short-term cultivation. A total of 15 P. vivax-infected blood samples were treated by both NWF filter and CF11 methods. The WBC removal rate of the NWF filter method was 99.03%, significantly higher than the CF11 methods (98.41%, P < 0.01). The RBC recovery rate of the NWF filter method was 95.48%, also significantly higher than the CF11 method (87.05%, P < 0.01). Fourteen in vitro short-term culture results showed that after filter treatment, P. vivax parasite could develop as normal as CF11 method, and no obvious density, developing stage difference were fund between two methods. NWF filter filtration removed most leukocytes from malaria-infected blood, and the recovery rate of RBCs was higher than with CF11 column method. Filtrated P. vivax parasites were morphologically normal, viable, and suitable for short-term in vitro culture. NWF filter filtration is simple, fast and robust, and is ideal for purification of malaria-infected blood.

  19. Ross filter development for absolute measurement of Al line radiation on MST

    Science.gov (United States)

    Lauersdorf, N.; Reusch, L. M.; den Hartog, D. J.; Goetz, J. A.; Franz, P.; Vanmeter, P.

    2017-10-01

    The MST has a two-color soft x-ray tomography (SXT) diagnostic that, using the double-filter technique, measures electron temperature (Te) from the slope of the soft x-ray (SXR) continuum. Because MST has an aluminum plasma-facing surface, bright Al line radiation occurs in the SXR spectrum. In past application of the double-filter technique, these lines have been filtered out using thick Be filters ( 400 μm and 800 μm), restricting the measurement temperature range to >=1 keV due to the signal strength having a positive correlation with Te. Another way to deal with the line radiation is to explicitly include it into the SXR spectrum analysis from which Te is derived. A Ross filter set has been designed to measure this line radiation, and will enable the absolute intensities of the aluminum lines to be quantified and incorporated into the analysis. The Ross filter will be used to measure Al+11 and Al+12 lines, occurring between 1.59 and 2.04 keV. By using multiple detectors with filters made of varying element concentrations, we create spectral bins in which the dominant transmission is the line radiation. Absolute measurement of Al line intensities will enable use of thinner filters in the SXT diagnostic and accurate measurement of Te < 1 keV. This material is based upon work supported by the U.S. Department of Energy Office of Science, Office of Fusion Energy Sciences program under Award Numbers DE-FC02-05ER54814 and DE-SC0015474.

  20. Developing a software for tracking the memory states of the machines in the LHCb Filter Farm

    CERN Document Server

    Jain, Harshit

    2017-01-01

    The LHCb Event Filter Farm consists of more than 1500 server nodes with a total amount of roughly 65 TB operating memory .The memory is crucial for the success of the LHCb experiment, since the proton-proton collisions are temporarily stored on these memory modules. Unfortunately, the aging nodes of the server farm occasionally suffer losses of their memory modules. The lower the available memory, the lower performance we can get out of it. Inducing the users or administrators to pay attention to this matter is inefficient. One needs to upgrade it to an acceptable way. The aim of this project was to develop a software to monitor a set of test machines. The software stores the data of the memory sticks in advance in a database which will be used for future reference. Then it checks the memory sticks at a future time instant to find any failures. In the case of any such losses the software looks up in the database to find out which memory sticks have lost and displays all information of those sticks in a log fi...

  1. Development of an ensemble Kalman filter data assimilation system for the Venusian atmosphere.

    Science.gov (United States)

    Sugimoto, Norihiko; Yamazaki, Akira; Kouyama, Toru; Kashimura, Hiroki; Enomoto, Takeshi; Takagi, Masahiro

    2017-08-24

    The size and mass of Venus is similar to those of the Earth; however, its atmospheric dynamics are considerably different and they are poorly understood due to limited observations and computational difficulties. Here, we developed a data assimilation system based on the local ensemble transform Kalman filter (LETKF) for a Venusian Atmospheric GCM for the Earth Simulator (VAFES), to make full use of the observational data. To examine the validity of the system, two datasets were assimilated separately into the VAFES forecasts forced with solar heating that excludes the diurnal component Qz; one was created from a VAFES run forced with solar heating that includes the diurnal component Qt, whereas the other was based on observations made by the Venus Monitoring Camera (VMC) onboard the Venus Express. The VAFES-LETKF system rapidly reduced the errors between the analysis and forecasts. In addition, the VAFES-LETKF system successfully reproduced the thermal tide excited by the diurnal component of solar heating, even though the second datasets only included horizontal winds at a single altitude on the dayside with a long interval of approximately one Earth day. This advanced system could be useful in the analysis of future datasets from the Venus Climate Orbiter 'Akatsuki'.

  2. Development of a Sigma-2 Receptor affinity filter through a Monte Carlo based QSAR analysis.

    Science.gov (United States)

    Rescifina, Antonio; Floresta, Giuseppe; Marrazzo, Agostino; Parenti, Carmela; Prezzavento, Orazio; Nastasi, Giovanni; Dichiara, Maria; Amata, Emanuele

    2017-08-30

    For the first time in sigma-2 (σ2) receptor field, a quantitative structure-activity relationship (QSAR) model has been built using pKi values of the whole set of known selective σ2 receptor ligands (548 compounds), taken from the Sigma-2 Receptor Selective Ligands Database (S2RSLDB) (http://www.researchdsf.unict.it/S2RSLDB/), through the Monte Carlo technique and employing the software CORAL. The model has been developed by using a large and structurally diverse set of compounds, allowing for a prediction of different populations of chemical compounds endpoint (σ2 receptor pKi). The statistical quality reached, suggested that model for pKi determination is robust and possesses a satisfactory predictive potential. The statistical quality is high for both visible and invisible sets. The screening of the FDA approved drugs, external to our dataset, suggested that sixteen compounds might be repositioned as σ2 receptor ligands (predicted pKi≥8). A literature check showed that six of these compounds have already been tested for affinity at σ2 receptor and, of these, two (Flunarizine and Terbinafine) have shown an experimental σ2 receptor pKi>7. This suggests that this QSAR model may be used as focusing screening filter in order to prospectively find or repurpose new drugs with high affinity for the σ2 receptor, and overall allowing for an enhanced hit rate respect to a random screening. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Development of particle filters for ships; Udvikling af partikelfiltre til skibe

    Energy Technology Data Exchange (ETDEWEB)

    Jakobsen, O.; Norre Holm, J.; Koecks, M. [Teknologisk Institut, Aarhus (Denmark)

    2013-04-01

    The project has resulted in a solution with a well-functioning maritime particle filter which reduces the particle emission significantly. The visible smoke from the vessels funnel, which typically is seen while manoeuvring in the harbour, is also reduced to a minimum. The system is constructed in such a way that the exhaust gases can be bypassed around the filter unit, in this situation to ensure the engines operation in case of filter clogging. The system has been provided with safety functions to prevent an excessive exhaust gas back-pressure and there are fitted remote controlled exhaust valves. Some of the challenges in the project have been the requirement from the engine manufacturer of keeping a low turbocharger back-pressure, besides the space conditions aboard the test vessel and the achievement of sufficient temperatures for regeneration of the particle filter. To oppose the requirement of low exhaust gas back-pressure, the filter housing was designed with space for twice as many monoliths as originally planned. In the funnel casing the original installations were removed to make space for the filter housing, and the system was enlarged with electrically controlled exhaust valves to improve the daily operation of the crew. The regeneration issue was solved by mounting electric automatically controlled heating elements in the filter housing and by an ash exhaust system. Regeneration is carried out by the crew when the vessel lies in harbour in the evening after the last tour of the day. Before mounting the particle filter, measurements were carried out aboard, showing a compound of particle emissions with an expected high NO{sub x}-level of 8.33 g/kW, whereas the other emissions were lower than expected at first. Especially HC and CO were very low, but also the particle mass (PM) had a relatively low value of 0.22 g/kWh. After commissioning the particle filter, a significant reduction of 93% of the particle number (N) was observed. A reduction in N was

  4. Development of a HPLC method for determination of four UV filters in sunscreen and its application to skin penetration studies.

    Science.gov (United States)

    Souza, Carla; Maia Campos, Patrícia M B G

    2017-12-01

    This study describes the development, validation and application of a high-performance liquid chromatography (HPLC) method for the simultaneous determination of the in vitro skin penetration profile of four UV filters on porcine skin. Experiments were carried out on a gel-cream formulation containing the following UV filters: diethylamino hydroxybenzoyl hexyl benzoate (DHHB), bis-ethylhexyloxyphenol methoxyphenyl triazine (BEMT), methylene bis-benzotriazolyl tetramethylbutylphenol (MBBT) and ethylhexyl triazone (EHT). The HPLC method demonstrated suitable selectivity, linearity (10.0-50.0 μg/mL), precision, accuracy and recovery from porcine skin and sunscreen formulation. The in vitro skin penetration profile was evaluated using Franz vertical diffusion cells for 24 h after application on porcine ear skin. None of the UV filters penetrated the porcine skin. Most of them stayed on the skin surface (>90%) and only BEMT, EHT and DHHB reached the dermis plus epidermis layer. These results are in agreement with previous results in the literature. Therefore, the analytical method was useful to evaluate the in vitro skin penetration of the UV filters and may help the development of safer and effective sunscreen products. Copyright © 2017 John Wiley & Sons, Ltd.

  5. Testing of ceramic filter materials at the PCFB test facility; Keraamisten suodinmateriaalien testaus PCFB-koelaitoksessa

    Energy Technology Data Exchange (ETDEWEB)

    Kuivalainen, R.; Eriksson, T.; Lehtonen, P.; Tiensuu, J. [Foster Wheeler Energia Oy, Karhula (Finland)

    1997-10-01

    Pressurized Circulating Fluidized Bed (PCFB) combustion technology has been developed in Karhula, Finland since 1986. In 1989, a 10 MW PCFB test facility was constructed. The test facility has been used for performance testing with different coal types through the years 1990-1994 for obtaining data for design and commercialization of the high-efficiency low-emission PCFB combustion technology. The main objective of the project Y53 was to evaluate advanced candle filter materials for the Hot Gas Clean-up Unit (HGCU) to be used in a commercial PCFB Demonstration Project. To achieve this goal, the selected candle materials were exposed to actual high temperature, high pressure coal combustion flue gases for a period of 1000-1500 h during the PCFB test runs. The test runs were carried out in three test segments in Foster Wheeler`s PCFB test facility at the Karhula R and D Center. An extensive inspection and sampling program was carried out after the second test segment. Selected sample candles were analyzed by the filter supplier and the preliminary results were encouraging. The material strength had decreased only within expected range. Slight elongation of the silicon carbide candles was observed, but at this phase the elongation can not be addressed to creep, unlike in the candles tested in 1993-94. The third and last test segment was completed successfully in October 1996. The filter system was inspected and several sample candles were selected for material characterization. The results will be available in February - March 1997. (orig.)

  6. Hot Gas Conditioning: Recent Progress with Larger-Scale Biomass Gasification Systems; Update and Summary of Recent Progress

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, D. J.

    2001-09-01

    As a result of environmental and policy considerations, there is increasing interest in using renewable biomass resources as feedstock for power, fuels, and chemicals and hydrogen. Biomass gasification is seen as an important technology component for expanding the use of biomass. Advanced biomass gasification systems provide clean products that can be used as fuel or synthesis gases in a variety of environmentally friendly processes. Advanced end-use technologies such as gas turbines or synthesis gas systems require high quality gases with narrowly defined specifications. Other systems such as boilers may also have fuel quality requirements, but they will be substantially less demanding. The gas product from biomass gasifiers contains quantities of particulates, tars, and other constituents that may exceed these specified limits. As a result, gas cleaning and conditioning will be required in most systems. Over the past decade, significant research and development activities have been conducted on the topic of gas cleanup and conditioning. This report provides an update of efforts related to large-scale biomass gasification systems and summarizes recent progress. Remaining research and development issues are also summarized.

  7. Development of Gel-Filter Method for High Enrichment of Low-Molecular Weight Proteins from Serum

    Science.gov (United States)

    Chen, Lingsheng; Zhai, Linhui; Li, Yanchang; Li, Ning; Zhang, Chengpu; Ping, Lingyan; Chang, Lei; Wu, Junzhu; Li, Xiangping; Shi, Deshun; Xu, Ping

    2015-01-01

    The human serum proteome has been extensively screened for biomarkers. However, the large dynamic range of protein concentrations in serum and the presence of highly abundant and large molecular weight proteins, make identification and detection changes in the amount of low-molecular weight proteins (LMW, molecular weight ≤ 30kDa) difficult. Here, we developed a gel-filter method including four layers of different concentration of tricine SDS-PAGE-based gels to block high-molecular weight proteins and enrich LMW proteins. By utilizing this method, we identified 1,576 proteins (n = 2) from 10 μL serum. Among them, 559 (n = 2) proteins belonged to LMW proteins. Furthermore, this gel-filter method could identify 67.4% and 39.8% more LMW proteins than that in representative methods of glycine SDS-PAGE and optimized-DS, respectively. By utilizing SILAC-AQUA approach with labeled recombinant protein as internal standard, the recovery rate for GST spiked in serum during the treatment of gel-filter, optimized-DS, and ProteoMiner was 33.1 ± 0.01%, 18.7 ± 0.01% and 9.6 ± 0.03%, respectively. These results demonstrate that the gel-filter method offers a rapid, highly reproducible and efficient approach for screening biomarkers from serum through proteomic analyses. PMID:25723528

  8. Development of gel-filter method for high enrichment of low-molecular weight proteins from serum.

    Directory of Open Access Journals (Sweden)

    Lingsheng Chen

    Full Text Available The human serum proteome has been extensively screened for biomarkers. However, the large dynamic range of protein concentrations in serum and the presence of highly abundant and large molecular weight proteins, make identification and detection changes in the amount of low-molecular weight proteins (LMW, molecular weight ≤ 30kDa difficult. Here, we developed a gel-filter method including four layers of different concentration of tricine SDS-PAGE-based gels to block high-molecular weight proteins and enrich LMW proteins. By utilizing this method, we identified 1,576 proteins (n = 2 from 10 μL serum. Among them, 559 (n = 2 proteins belonged to LMW proteins. Furthermore, this gel-filter method could identify 67.4% and 39.8% more LMW proteins than that in representative methods of glycine SDS-PAGE and optimized-DS, respectively. By utilizing SILAC-AQUA approach with labeled recombinant protein as internal standard, the recovery rate for GST spiked in serum during the treatment of gel-filter, optimized-DS, and ProteoMiner was 33.1 ± 0.01%, 18.7 ± 0.01% and 9.6 ± 0.03%, respectively. These results demonstrate that the gel-filter method offers a rapid, highly reproducible and efficient approach for screening biomarkers from serum through proteomic analyses.

  9. Development and evaluation of a plant-based air filter system for ...

    African Journals Online (AJOL)

    We investigated a novel plant-based air filter system for bacterial growth control. The volatile components released from the experimental plant (Cupressus macrocarpa) were used as the basis of the bacterial growth control and inhibition. We monitored the effect of light on the gas exhausted from the system, and we found ...

  10. Development and evaluation of a plant-based air filter system for ...

    African Journals Online (AJOL)

    Y. Choi

    2013-04-17

    Apr 17, 2013 ... We investigated a novel plant-based air filter system for bacterial growth control. The volatile components released from the experimental plant (Cupressus macrocarpa) were used as the basis of the bacterial growth control and inhibition. We monitored the effect of light on the gas exhausted from.

  11. Ceramic fiber filter technology

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Microwave Filters

    OpenAIRE

    Zhou, Jiafeng

    2010-01-01

    The general theory of microwave filter design based on lumped-element circuit is described in this chapter. The lowpass prototype filters with Butterworth, Chebyshev and quasielliptic characteristics are synthesized, and the prototype filters are then transformed to bandpass filters by lowpass to bandpass frequency mapping. By using immitance inverters ( J - or K -inverters), the bandpass filters can be realized by the same type of resonators. One design example is given to verify the theory ...

  13. Generic Kalman Filter Software

    Science.gov (United States)

    Lisano, Michael E., II; Crues, Edwin Z.

    2005-01-01

    The Generic Kalman Filter (GKF) software provides a standard basis for the development of application-specific Kalman-filter programs. Historically, Kalman filters have been implemented by customized programs that must be written, coded, and debugged anew for each unique application, then tested and tuned with simulated or actual measurement data. Total development times for typical Kalman-filter application programs have ranged from months to weeks. The GKF software can simplify the development process and reduce the development time by eliminating the need to re-create the fundamental implementation of the Kalman filter for each new application. The GKF software is written in the ANSI C programming language. It contains a generic Kalman-filter-development directory that, in turn, contains a code for a generic Kalman filter function; more specifically, it contains a generically designed and generically coded implementation of linear, linearized, and extended Kalman filtering algorithms, including algorithms for state- and covariance-update and -propagation functions. The mathematical theory that underlies the algorithms is well known and has been reported extensively in the open technical literature. Also contained in the directory are a header file that defines generic Kalman-filter data structures and prototype functions and template versions of application-specific subfunction and calling navigation/estimation routine code and headers. Once the user has provided a calling routine and the required application-specific subfunctions, the application-specific Kalman-filter software can be compiled and executed immediately. During execution, the generic Kalman-filter function is called from a higher-level navigation or estimation routine that preprocesses measurement data and post-processes output data. The generic Kalman-filter function uses the aforementioned data structures and five implementation- specific subfunctions, which have been developed by the user on

  14. Toward the Development of a Coupled COAMPS-ROMS Ensemble Kalman Filter and Adjoint with a focus on the Indian Ocean and the Intraseasonal Oscillation

    Science.gov (United States)

    2015-09-30

    1 Approved for public release; distribution is unlimited. Toward the Development of a Coupled COAMPS-ROMS Ensemble Kalman Filter and Adjoint...system at NCAR. (2) Compare the performance of the Ensemble Kalman Filter (EnKF) using the Data Assimilation Research Testbed (DART) and 4

  15. Development of Compact and Low-Crosstalk PLC-WDM Filters for Hybrid-Integrated Bidirectional Optical Transceivers

    Science.gov (United States)

    Kim, Kyoung-Youm; Kim, Se Yoon; Kim, Myoung Won; Jung, Suntae

    2005-05-01

    This paper reports on the development of planar-lightwave-circuit wavelength-division-multiplexing (PLC-WDM) filters based on double polynomial curve directional couplers, which will be integrated into compact and low-cost bidirectional optical transceivers for FTTx systems. Silica-based PLC-WDM filters smaller than 5 mm x 100 m for Ethernet passive optical network (E-PON) applications were designed and fabricated to have low bidirectional crosstalk (lower than -40 dB) as well as low insertion losses (lower than 1 dB) within the operating temperatures of -40 to 80 ° C. Several features and design guides that can reduce the size of directional couplers and improve the level of bidirectional crosstalk are discussed.

  16. SU-F-J-28: Development of a New Imaging Filter to Remove the Shadows From the Carbon Fiber Grid Table Top

    Energy Technology Data Exchange (ETDEWEB)

    Maehana, W [Kanagawa Cancer Center, Yokohama, Kanagawa (Japan); Yokohama National University, Yokohama, kanagawa (Japan); Nagao, T [Yokohama National University, Yokohama, kanagawa (Japan)

    2016-06-15

    Purpose: For the image guided radiation therapy (IGRT), the shadows caused by the construction of the treatment couch top adversely affect the visual evaluation. Therefore, we developed the new imaging filter in order to remove the shadows. The performance of the new filter was evaluated using the clinical images. Methods: The new filter was composed of the band-pass filter (BPF) weighted by the k factor and the low-pass filter (LPF). In the frequency region, the stop bandwidth were 8.3×10{sup 3} mm{sup −1} on u direction and 11.1×10{sup 3} mm{sup −1} on v direction for the BPF, and the pass bandwidth were 8.3×10{sup 3} mm{sup −1} on u direction and 11.1×10{sup 3} mm{sup −1} on v direction for the LPF. After adding the filter, the shadows from the carbon fiber grid table top (CFGTT, Varian) on the kV-image was removed. To check the filter effect, we compared the clinical images, which are thorax and thoracoabdominal region, with to without the filter. The subjective evaluation tests was performed by adapting a three-point scale (agree, neither agree nor disagree, disagree) about the 15 persons in the department of radiation oncology. Results: We succeeded in removing all shadows of CFGTT using the new filter. This filter is very useful shown by the results of the subjective evaluation having the 23/30 persons agreed to the filtered clinical images. Conclusion: We concluded that the proposed method was useful tool for the IGRT and the new filter leads to improvement of the accuracy of radiation therapy.

  17. Development of Filtered Bispectrum for EEG Signal Feature Extraction in Automatic Emotion Recognition Using Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    Prima Dewi Purnamasari

    2017-05-01

    Full Text Available The development of automatic emotion detection systems has recently gained significant attention due to the growing possibility of their implementation in several applications, including affective computing and various fields within biomedical engineering. Use of the electroencephalograph (EEG signal is preferred over facial expression, as people cannot control the EEG signal generated by their brain; the EEG ensures a stronger reliability in the psychological signal. However, because of its uniqueness between individuals and its vulnerability to noise, use of EEG signals can be rather complicated. In this paper, we propose a methodology to conduct EEG-based emotion recognition by using a filtered bispectrum as the feature extraction subsystem and an artificial neural network (ANN as the classifier. The bispectrum is theoretically superior to the power spectrum because it can identify phase coupling between the nonlinear process components of the EEG signal. In the feature extraction process, to extract the information contained in the bispectrum matrices, a 3D pyramid filter is used for sampling and quantifying the bispectrum value. Experiment results show that the mean percentage of the bispectrum value from 5 × 5 non-overlapped 3D pyramid filters produces the highest recognition rate. We found that reducing the number of EEG channels down to only eight in the frontal area of the brain does not significantly affect the recognition rate, and the number of data samples used in the training process is then increased to improve the recognition rate of the system. We have also utilized a probabilistic neural network (PNN as another classifier and compared its recognition rate with that of the back-propagation neural network (BPNN, and the results show that the PNN produces a comparable recognition rate and lower computational costs. Our research shows that the extracted bispectrum values of an EEG signal using 3D filtering as a feature extraction

  18. Sticky superhydrophobic filter paper developed by dip-coating of fluorinated waterborne epoxy emulsion

    Science.gov (United States)

    Huang, Xiangxuan; Wen, Xiufang; Cheng, Jiang; Yang, Zhuoru

    2012-09-01

    A superhydrophobic and superoleophilic coating for oil filter paper was synthesized based on waterborne bisphenol-A novolac epoxy emulsion. The benzoic acid (BA) and maleic anhydride (MA) were used as modification agents to give the epoxy resin hydrophilic groups (carboxyl) and Cdbnd C double bonds. And the fluorinated waterborne epoxy emulsion was prepared by free radical solution polymerization of dodecafluoroheptyl methacrylate (DFMA) monomer. The covalent bound low free energy fluorinated chains in the monomer reduce the surface energy of solidification polymers sufficiently to give rise to superhydrophobic behavior while conserving superoleophilicity. Surfaces prepared show a sticky property, which exhibits a static water contact angle of 152° for a 5 μL droplet that does not slid off even when the sample is held upside down. This synthetic emulsion is simple and convenient as impregnating agent for filter paper, which can be considered as a suitable candidate for various substrates such as cotton textiles, E-glass and artificial fiber, and so on.

  19. Optimal filtering

    CERN Document Server

    Anderson, Brian D O

    1979-01-01

    This graduate-level text augments and extends beyond undergraduate studies of signal processing, particularly in regard to communication systems and digital filtering theory. Vital for students in the fields of control and communications, its contents are also relevant to students in such diverse areas as statistics, economics, bioengineering, and operations research.Topics include filtering, linear systems, and estimation; the discrete-time Kalman filter; time-invariant filters; properties of Kalman filters; computational aspects; and smoothing of discrete-time signals. Additional subjects e

  20. Development of Highly Sensitive and Selective Breathing Sensors Using Molecular Imprinted Filtering for Diabetic and Alcoholic Patients

    Science.gov (United States)

    Bhuiyan, Md. Saleh Akram

    Wellness sensor technology is an emerging diagnostic test research field, which mostly deal with the point of care of the patients in the recent days. Due to the lack of awareness from the patients, most diseases cannot be detected in due time. This led to worse conditions, such as diabetic and alcoholic syndrome. Therefore, many research groups have been working to develop portable sensor devices that can track serious diseases. These include diabetic and alcoholic biomarkers in breathing. These devices have very high selectivity and reliability. However, the major limitation of biomarkers is that it deals with the bio-molecular based sensing mechanism. Extensive challenges exist in the selectivity and reliability of breathing sensors. These require development of proper materials and effective detection methods. Thus, selection of proper materials, correct sensing parameters, effective device architecture and simple fabrication processing are substantially critical. The goal of this work is to develop graphene based breathing sensors with high selectivity and sensitivity using a novel molecular imprinted filtering technique. The sensors have various applications including Point of Care Testing (POCT) device for personalized home and clinical use in early detection of diabetic and alcoholic patients. Different fabrication procedures were used to optimize the sensor performance. The optimized results demonstrate that a proper biomarker molecule imprinting process could selectively detect diabetes and alcohol. The graphene layer was optimized by maintaining spray coating time, pattern and distance between the substrate and spray coater. Graphene adhesion to the substrate was also improved using polyvinyl pyrrolidone. The molecular imprinting filter made on top of the graphene layer improved the performance of acetone and ethanol molecule detection, indicated by the change of resistance in the graphene layer. The sensors showed poor performance for long-time exposure

  1. The Identification of Filters and Interdependencies for Effective Resource Allocation: Coupling the Mitigation of Natural Hazards to Economic Development.

    Science.gov (United States)

    Agar, S. M.; Kunreuther, H.

    2005-12-01

    Policy formulation for the mitigation and management of risks posed by natural hazards requires that governments confront difficult decisions for resource allocation and be able to justify their spending. Governments also need to recognize when spending offers little improvement and the circumstances in which relatively small amounts of spending can make substantial differences. Because natural hazards can have detrimental impacts on local and regional economies, patterns of economic development can also be affected by spending decisions for disaster mitigation. This paper argues that by mapping interdependencies among physical, social and economic factors, governments can improve resource allocation to mitigate the risks of natural hazards while improving economic development on local and regional scales. Case studies of natural hazards in Turkey have been used to explore specific "filters" that act to modify short- and long-term outcomes. Pre-event filters can prevent an event from becoming a natural disaster or change a routine event into a disaster. Post-event filters affect both short and long-term recovery and development. Some filters cannot be easily modified by spending (e.g., rural-urban migration) but others (e.g., land-use practices) provide realistic spending targets. Net social benefits derived from spending, however, will also depend on the ways by which filters are linked, or so-called "interdependencies". A single weak link in an interdependent system, such as a power grid, can trigger a cascade of failures. Similarly, weak links in social and commercial networks can send waves of disruption through communities. Conversely, by understanding the positive impacts of interdependencies, spending can be targeted to maximize net social benefits while mitigating risks and improving economic development. Detailed information on public spending was not available for this study but case studies illustrate how networks of interdependent filters can modify

  2. Nanofiber filter media for air filtration

    Science.gov (United States)

    Raghavan, Bharath Kumar

    Nanofibers have higher capture efficiencies in comparison to microfibers in the submicron particle size range of 100-500 nm because of small fiber diameter and increased surface area of the fibers. Pressure drop across the filter increases tremendously with decrease in fiber diameter in the continuum flow regime. Nanofibers with fiber diameter less than 300 nm are in the slip flow regime as a consequence of which steep increase in pressure drop is considerably reduced due to slip effect. The outlet or inlet gases have broad range of particle size distribution varying from few micrometers to nanometers. The economic benefits include capture of a wide range of particle sizes in the gas streams using compact filters composed of nanofibers and microfibers. Electrospinning technique was used to successfully fabricate polymeric and ceramic nanofibers. The nanofibers were long, continuous, and flexible with diameters in the range of 200--300 nm. Nanofibers were added to the filter medium either by mixing microfibers and nanofibers or by directly electrospinning nanofibers as thin layer on the surface of the microfiber filter medium. Experimental results showed that either by mixing Nylon 6 nanofibers with B glass fibers or by electrospinning Nylon 6 nanofibers as a thin layer on the surface of the microfiber medium in the surface area ratio of 1 which is 0.06 g of nanofibers for 2 g of microfibers performed better than microfiber filter media in air filtration tests. This improved performance is consistent with numerical modeling. The particle loading on a microfibrous filter were studied for air filtration tests. The experimental and modeling results showed that both pressure drop and capture efficiency increased with loading time. Nanofiber filter media has potential applications in many filtration applications and one of them being hot gas filtration. Ceramic nanofibers made of alumina and titania nanofibers can withstand in the range of 1000°C. Ceramic nanofibers

  3. Nanofiber Filters Eliminate Contaminants

    Science.gov (United States)

    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.

  4. Development of multi-filter spectroradiometry; Filter hoshiki ni yoru bunka hosharyo no keisoku hoho to sono supekutoru no hyogen hoho ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Miyake, Y.; Aoshima, T.; Minoda, T.; Kato, T.; Kondo, S. [Eiko Instruments Trading Co. Ltd., Tokyo (Japan)

    1996-10-27

    Described in this paper is a technique of solar radiation spectroradiometry in which high-resolution wavelength computation adds to a multi-filter method. The solar spectrum upon entering the atmosphere is scattered and absorbed by parameter-constituting elements such as gas, aerosol, cloud particles, etc., and its spectral contour is complicatedly deformed relative to wavelength. Taking advantage of the fact that the scattering and absorbing characteristics of some of the elements are constant relative to wavelength, a simple equation was constructed to enable high-resolution spectrum measurement wavelength-wise, and this compensates for the limit in measurable wavelength that the conventional multi-filter method suffers from. The new method discussed here is not so expensive as the grating method thanks to the employment of filters, is capable of determining spectral radiation quantities with a precision of {plus_minus}5%, and is reduced in terms of the capacity of memory for data storage. The new method enables data collection under various atmospheric conditions that the four seasons present, which the difficult-to-apply and expensive spectroradiometer fails. It is expected that this method will find its use in collecting basic data for the designing of photovoltaic power generation systems, in the study of photochemical reaction in agriculture, and in collecting basic data for daylight lighting. 1 ref., 6 figs., 2 tabs.

  5. District-level hospital trauma care audit filters: Delphi technique for defining context-appropriate indicators for quality improvement initiative evaluation in developing countries.

    Science.gov (United States)

    Stewart, Barclay T; Gyedu, Adam; Quansah, Robert; Addo, Wilfred Larbi; Afoko, Akis; Agbenorku, Pius; Amponsah-Manu, Forster; Ankomah, James; Appiah-Denkyira, Ebenezer; Baffoe, Peter; Debrah, Sam; Donkor, Peter; Dorvlo, Theodor; Japiong, Kennedy; Kushner, Adam L; Morna, Martin; Ofosu, Anthony; Oppong-Nketia, Victor; Tabiri, Stephen; Mock, Charles

    2016-01-01

    Prospective clinical audit of trauma care improves outcomes for the injured in high-income countries (HICs). However, equivalent, context-appropriate audit filters for use in low- and middle-income country (LMIC) district-level hospitals have not been well established. We aimed to develop context-appropriate trauma care audit filters for district-level hospitals in Ghana, was well as other LMICs more broadly. Consensus on trauma care audit filters was built between twenty panellists using a Delphi technique with four anonymous, iterative surveys designed to elicit: (i) trauma care processes to be measured; (ii) important features of audit filters for the district-level hospital setting; and (iii) potentially useful filters. Filters were ranked on a scale from 0 to 10 (10 being very useful). Consensus was measured with average percent majority opinion (APMO) cut-off rate. Target consensus was defined a priori as: a median rank of ≥9 for each filter and an APMO cut-off rate of ≥0.8. Panellists agreed on trauma care processes to target (e.g. triage, phases of trauma assessment, early referral if needed) and specific features of filters for district-level hospital use (e.g. simplicity, unassuming of resource capacity). APMO cut-off rate increased successively: Round 1--0.58; Round 2--0.66; Round 3--0.76; and Round 4--0.82. After Round 4, target consensus on 22 trauma care and referral-specific filters was reached. Example filters include: triage--vital signs are recorded within 15 min of arrival (must include breathing assessment, heart rate, blood pressure, oxygen saturation if available); circulation--a large bore IV was placed within 15 min of patient arrival; referral--if referral is activated, the referring clinician and receiving facility communicate by phone or radio prior to transfer. This study proposes trauma care audit filters appropriate for LMIC district-level hospitals. Given the successes of similar filters in HICs and obstetric care filters in LMICs

  6. Hybrid Filter Membrane

    Science.gov (United States)

    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

  7. Power Systems Development Facility Gasification Test Campaign TC25

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services

    2008-12-01

    In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF), located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR Transport Gasifier, a hot gas particulate control device, advanced syngas cleanup systems, and high-pressure solids handling systems. This report summarizes the results of TC25, the second test campaign using a high moisture lignite coal from the Red Hills mine in Mississippi as the feedstock in the modified Transport Gasifier configuration. TC25 was conducted from July 4, 2008, through August 12, 2008. During TC25, the PSDF gasification process operated for 742 hours in air-blown gasification mode. Operation with the Mississippi lignite was significantly improved in TC25 compared to the previous test (TC22) with this fuel due to the addition of a fluid bed coal dryer. The new dryer was installed to dry coals with very high moisture contents for reliable coal feeding. The TC25 test campaign demonstrated steady operation with high carbon conversion and optimized performance of the coal handling and gasifier systems. Operation during TC25 provided the opportunity for further testing of instrumentation enhancements, hot gas filter materials, and advanced syngas cleanup technologies. The PSDF site was also made available for testing of the National Energy Technology Laboratory's fuel cell module and Media Process Technology's hydrogen selective membrane with syngas from the Transport Gasifier.

  8. Power Systems Development Facility Gasification Test Campaign TC24

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services

    2008-03-30

    In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF), located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR Transport Gasifier, a hot gas particulate control device, advanced syngas cleanup systems, and high-pressure solids handling systems. This report summarizes the results of TC24, the first test campaign using a bituminous coal as the feedstock in the modified Transport Gasifier configuration. TC24 was conducted from February 16, 2008, through March 19, 2008. The PSDF gasification process operated for about 230 hours in air-blown gasification mode with about 225 tons of Utah bituminous coal feed. Operational challenges in gasifier operation were related to particle agglomeration, a large percentage of oversize coal particles, low overall gasifier solids collection efficiency, and refractory degradation in the gasifier solids collection unit. The carbon conversion and syngas heating values varied widely, with low values obtained during periods of low gasifier operating temperature. Despite the operating difficulties, several periods of steady state operation were achieved, which provided useful data for future testing. TC24 operation afforded the opportunity for testing of various types of technologies, including dry coal feeding with a developmental feeder, the Pressure Decoupled Advanced Coal (PDAC) feeder; evaluating a new hot gas filter element media configuration; and enhancing syngas cleanup with water-gas shift catalysts. During TC24, the PSDF site was also made available for testing of the National Energy Technology Laboratory's fuel cell module and Media Process Technology's hydrogen selective membrane.

  9. Advanced Filtering Techniques Applied to Spaceflight Project

    Data.gov (United States)

    National Aeronautics and Space Administration — IST-Rolla developed two nonlinear filters for spacecraft orbit determination during the Phase I contract. The theta-D filter and the cost based filter, CBF, were...

  10. Development of 2.8 V Ketjen black supercapacitors with high rate capabilities for AC line filtering

    Science.gov (United States)

    Yoo, Yongju; Park, Jinwoo; Kim, Min-Seop; Kim, Woong

    2017-08-01

    Supercapacitors are generally more compact than conventional bulky aluminum electrolytic capacitors (AECs). Replacement of AECs with supercapacitors can lead to miniaturization of electronic devices. However, even state-of-the-art supercapacitors developed in laboratories are superior to or competitive with AECs only in low voltage applications (graphitic nature of KB, we demonstrate that the voltage limit can be extended to 53 V. The KB supercapacitor exhibits excellent areal capacitance, cell voltage, and phase angle values of ∼574 μF cm-2, 2.8 V, and ∼-80°, respectively. In addition, we demonstrate that an AC line filtering circuit with three supercapacitors connected in series can extend the application voltage without significant sacrifice in rate capability (ϕ ∼ -77° at 120 Hz). On the other hand, KBs are much less expensive than carbon materials previously demonstrated for AC line filtering and hence are very attractive for practical applications. We believe that this demonstration of high-performance supercapacitors made from low-cost carbon materials is both scientifically interesting and important for practical applications.

  11. Analog active filters

    Science.gov (United States)

    Ghausi, M. S.

    1984-01-01

    The evolution of active filters during the time from 1920 to 1980 is considered, taking into account the hardware used to implement a filtering network for voice frequency over 60 years. From 1920 to 1960 the majority of voice-frequency filters was realized as discrete RLC networks. After the development of transistors, it was realized that size and cost reductions could be achieved by replacing the inductors with active networks. In the early 1970's, batch-processed thin-film hybrid integrated circuits began to be employed. The synthesis of transfer functions which are predominantly input/output types is considered. Attention is given to direct realizations, synthesis using component simulation, cascade synthesis, multiple-loop feedback design, active-R and active-C filters, aspects of sensitivity, and switched-capacitor filters.

  12. THz Discrimination of Materials: Development of an Apparatus Based on Room Temperature Detection and Metasurfaces Selective Filters

    Science.gov (United States)

    Carelli, P.; Chiarello, F.; Torrioli, G.; Castellano, M. G.

    2017-03-01

    We present an apparatus for terahertz discrimination of materials designed to be fast, simple, compact, and economical in order to be suitable for preliminary on-field analysis. The system working principles, bio-inspired by the human vision of colors, are based on the use of an incoherent source, a room temperature detector, a series of microfabricated metamaterials selective filters, a very compact optics based on metallic ellipsoidal mirrors in air, and a treatment of the mirrors' surfaces that select the frequency band of interest. We experimentally demonstrate the operation of the apparatus in discriminating simple substances such as salt, staple foods, and grease. We present the system and the obtained results and discuss issues and possible developments.

  13. Analog filters in nanometer CMOS

    CERN Document Server

    Uhrmann, Heimo; Zimmermann, Horst

    2014-01-01

    Starting from the basics of analog filters and the poor transistor characteristics in nanometer CMOS 10 high-performance analog filters developed by the authors in 120 nm and 65 nm CMOS are described extensively. Among them are gm-C filters, current-mode filters, and active filters for system-on-chip realization for Bluetooth, WCDMA, UWB, DVB-H, and LTE applications. For the active filters several operational amplifier designs are described. The book, furthermore, contains a review of the newest state of research on low-voltage low-power analog filters. To cover the topic of the book comprehensively, linearization issues and measurement methods for the characterization of advanced analog filters are introduced in addition. Numerous elaborate illustrations promote an easy comprehension. This book will be of value to engineers and researchers in industry as well as scientists and Ph.D students at universities. The book is also recommendable to graduate students specializing on nanoelectronics, microelectronics ...

  14. Development of Filter-Blower Unit for use in the Advanced Nuclear Biological Chemical Protection System (ANBCPS) Helicopter/Transport-aircraft version

    NARCIS (Netherlands)

    Sabel, R.; Reffeltrath, P.A.; Jonkman, A.; Post, T.

    2006-01-01

    As a participant in the three-nation partnership for development of the ANBCP-S for use in Helicopters, Transport Aircraft and Fast Jet, the Royal Netherlands Airforce (RNLAF) picked up the challenge to design a Filter- Blower-Unit (FBU). Major Command (MajCom) of the RNLAF set priority to develop a

  15. Sediment plume development from forest roads: How are they related to filter strip recommendations

    Science.gov (United States)

    Johnny M. Grace

    2004-01-01

    Forest roads have been presented as the major source of soil erosion from forestactivities in recent years. Controlling sediment movement from forest roads is emphasizedin forest management throughout the nation. However, design and development of BestManagement Practices (BMPs) to control sediment movement from the forest road prismrequires a better understanding of...

  16. Development of polarized {sup 3}He filter for polarized neutron experiment

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, K.; Sato, H.; Yoshimi, A.; Asahi, K. [Tokyo Inst. of Tech. (Japan). Faculty of Science; Masuda, Y.; Muto, S.; Ishimoto, S.; Morimoto, K.

    1996-08-01

    A high-pressure polarized {sup 3}He gas cell, pumped with two diode lasers, has been developed at KEK for use as a polarizer and a spin analyzer for low energy neutrons. The polarization attained of {sup 3}He was determined through the measurement of the transmission of the unpolarized neutrons through the {sup 3}He cell. So far we obtained P{sub He}=18% at 10 atm and P{sub He}=12% at 20 atm. (author)

  17. Impact of Chloramination on the Development of Laboratory-Grown Biofilms Fed with Filter-Pretreated Groundwater

    Science.gov (United States)

    Ling, Fangqiong; Liu, Wen-Tso

    2013-01-01

    This study evaluated the continuous impact of monochloramine disinfection on laboratory-grown biofilms through the characterization of biofilm architecture and microbial community structure. Biofilm development and disinfection were achieved using CDC (Centers for Disease Control and Prevention) biofilm reactor systems with polyvinyl chloride (PVC) coupons as the substratum and sand filter-pretreated groundwater as the source of microbial seeding and growth nutrient. After 2 weeks of growth, the biofilms were subjected to chloramination for 8 more weeks at concentrations of 7.5±1.4 to 9.1±0.4 mg Cl2 L−1. Control reactors received no disinfection during the development of biofilms. Confocal laser scanning microscopy and image analysis indicated that chloramination could lead to 81.4–83.5% and 86.3–95.6% reduction in biofilm biomass and thickness, respectively, but could not eliminate biofilm growth. 16S rRNA gene terminal restriction fragment length polymorphism analysis indicated that microbial community structures between chloraminated and non-chloraminated biofilms exhibited different successional trends. 16S rRNA gene pyrosequencing analysis further revealed that chloramination could select members of Actinobacteria and Acidobacteria as the dominant populations, whereas natural development leads to the selection of members of Nitrospira and Bacteroidetes as dominant biofilm populations. Overall, chloramination treatment could alter the growth of multi-species biofilms on the PVC surface, shape the biofilm architecture, and select a certain microbial community that can survive or proliferate under chloramination. PMID:23124766

  18. Impact of Chloramination on the Development of Laboratory-Grown Biofilms Fed with Filter-Pretreated Groundwater

    KAUST Repository

    Ling, Fangqiong

    2013-01-01

    This study evaluated the continuous impact of monochloramine disinfection on laboratory-grown biofilms through the characterization of biofilm architecture and microbial community structure. Biofilm development and disinfection were achieved using CDC (Centers for Disease Control and Prevention) biofilm reactor systems with polyvinyl chloride (PVC) coupons as the substratum and sand filter-pretreated groundwater as the source of microbial seeding and growth nutrient. After 2 weeks of growth, the biofilms were subjected to chloramination for 8 more weeks at concentrations of 7.5±1.4 to 9.1±0.4 mg Cl2 L-1. Control reactors received no disinfection during the development of biofilms. Confocal laser scanning microscopy and image analysis indicated that chloramination could lead to 81.4-83.5% and 86.3-95.6% reduction in biofilm biomass and thickness, respectively, but could not eliminate biofilm growth. 16S rRNA gene terminal restriction fragment length polymorphism analysis indicated that microbial community structures between chloraminated and non-chloraminated biofilms exhibited different successional trends. 16S rRNA gene pyrosequencing analysis further revealed that chloramination could select members of Actinobacteria and Acidobacteria as the dominant populations, whereas natural development leads to the selection of members of Nitrospira and Bacteroidetes as dominant biofilm populations. Overall, chloramination treatment could alter the growth of multi-species biofilms on the PVC surface, shape the biofilm architecture, and select a certain microbial community that can survive or proliferate under chloramination.

  19. Driving Force Filtering and Driving Mechanism Analysis of Urban Agricultural Development in Weifang County, China

    Directory of Open Access Journals (Sweden)

    SUI Fei-fei

    2016-03-01

    Full Text Available As an agricultural nation, the agricultural landscape is the basic appearance and existence in China, but the common existence often be neglected and contempted. As a new type of design and ideology, the development of urban agricultural landscape will greatly affect the texture and structure of the urban space. According to the urban agricultural production data and the socio-economic data of Weifang County, a set of evaluation index system that could analyze quantitatively the driving force of urban agricultural production changes and the internal drive mechanism was built. The original driving force indicators of economy, society, resources and environment from the time-series were chosen, and then 15 driving forces from the original driving forces by correlation analysis and principal component analysis were selected. The degree of influence was analyzed and the driving forces model by means of partial least squares(PLS was built. The results demonstrated that the factors greatly influenced the increase of urban agricultural output value in Weifang County were per capita net income of rural residents, agricultural machinery total power, effective irrigation area, centralized treatment rate of urban sewage, with the driving exponents 0.2509, 0.1019, 0.1655, 0.1332, respectively. The negative influence factor was the use amount of agricultural plastic film and the driving exponent was-0.2146. The research provides a reference for the development of urban agriculture, as well as a reference for the related study.

  20. Development of a predictive model for 6 month survival in patients with venous thromboembolism and solid malignancy requiring IVC filter placement.

    Science.gov (United States)

    Huang, Steven Y; Odisio, Bruno C; Sabir, Sharjeel H; Ensor, Joe E; Niekamp, Andrew S; Huynh, Tam T; Kroll, Michael; Gupta, Sanjay

    2017-07-01

    Our purpose was to develop a predictive model for short-term survival (i.e. modeling was used to assess variables associated with 6 month survival following filter placement in patients with VTE and solid malignancy. Significant variables were used to generate a predictive model. 397 patients with solid malignancy received a filter during the study period. Three variables were associated with 6 month survival: (1) serum albumin [hazard ratio (HR) 0.496, P predictive model to estimate 6 month survival with an area under the receiver operating characteristic curve of 0.815, sensitivity of 0.782, and specificity of 0.715. Six month survival in patients with VTE and solid malignancy requiring filter placement can be predicted from three patient variables. Our predictive model could be used to help physicians decide whether a permanent or retrievable filter may be more appropriate as well as to assess the risks and benefits for filter retrieval within the context of survival longevity in patients with cancer.

  1. On the possibility of developing incoherent fibre-optic data transmission systems based on signal spectral coding with matched acousto-optical filters

    Energy Technology Data Exchange (ETDEWEB)

    Proklov, Valerii V; Byshevski-Konopko, O A; Grigorievski, V I [V.A.Kotel' nikov Institute of Radio Engineering and Electronics, Russian Academy of Sciences, Fryazino branch, Fryazino, Moscow Region (Russian Federation)

    2013-06-30

    The scheme is suggested for developing the optical communication line based on the principle of code division of multiple access with matched acousto-optical filters and a 16-bit long Walsh sequence. Results of modelling show that such a line can operate if adjacent spectral lines are separated by at least double the Rayleigh criterion. (optical information transmission)

  2. On the possibility of developing incoherent fibre-optic data transmission systems based on signal spectral coding with matched acousto-optical filters

    Science.gov (United States)

    Proklov, Valerii V.; Byshevski-Konopko, O. A.; Grigorievski, V. I.

    2013-06-01

    The scheme is suggested for developing the optical communication line based on the principle of code division of multiple access with matched acousto-optical filters and a 16-bit long Walsh sequence. Results of modelling show that such a line can operate if adjacent spectral lines are separated by at least double the Rayleigh criterion.

  3. Water Filters

    Science.gov (United States)

    1988-01-01

    Seeking to find a more effective method of filtering potable water that was highly contaminated, Mike Pedersen, founder of Western Water International, learned that NASA had conducted extensive research in methods of purifying water on board manned spacecraft. The key is Aquaspace Compound, a proprietary WWI formula that scientifically blends various types of glandular activated charcoal with other active and inert ingredients. Aquaspace systems remove some substances; chlorine, by atomic adsorption, other types of organic chemicals by mechanical filtration and still others by catalytic reaction. Aquaspace filters are finding wide acceptance in industrial, commercial, residential and recreational applications in the U.S. and abroad.

  4. Filter apparatus

    Science.gov (United States)

    Kuban, D.P.; Singletary, B.H.; Evans, J.H.

    A plurality of holding tubes are respectively mounted in apertures in a partition plate fixed in a housing receiving gas contaminated with particulate material. A filter cartridge is removably held in each holding tube, and the cartridges and holding tubes are arranged so that gas passes through apertures therein and across the the partition plate while particulate material is collected in the cartridges. Replacement filter cartridges are respectively held in holding canisters mounted on a support plate which can be secured to the aforesaid housing, and screws mounted on said canisters are arranged to push replacement cartridges into the cartridge holding tubes and thereby eject used cartridges therefrom.

  5. Inorganic UV filters

    Directory of Open Access Journals (Sweden)

    Eloísa Berbel Manaia

    2013-06-01

    Full Text Available Nowadays, concern over skin cancer has been growing more and more, especially in tropical countries where the incidence of UVA/B radiation is higher. The correct use of sunscreen is the most efficient way to prevent the development of this disease. The ingredients of sunscreen can be organic and/or inorganic sun filters. Inorganic filters present some advantages over organic filters, such as photostability, non-irritability and broad spectrum protection. Nevertheless, inorganic filters have a whitening effect in sunscreen formulations owing to the high refractive index, decreasing their esthetic appeal. Many techniques have been developed to overcome this problem and among them, the use of nanotechnology stands out. The estimated amount of nanomaterial in use must increase from 2000 tons in 2004 to a projected 58000 tons in 2020. In this context, this article aims to analyze critically both the different features of the production of inorganic filters (synthesis routes proposed in recent years and the permeability, the safety and other characteristics of the new generation of inorganic filters.

  6. Adaptive noise Wiener filter for scanning electron microscope imaging system.

    Science.gov (United States)

    Sim, K S; Teh, V; Nia, M E

    2016-01-01

    Noise on scanning electron microscope (SEM) images is studied. Gaussian noise is the most common type of noise in SEM image. We developed a new noise reduction filter based on the Wiener filter. We compared the performance of this new filter namely adaptive noise Wiener (ANW) filter, with four common existing filters as well as average filter, median filter, Gaussian smoothing filter and the Wiener filter. Based on the experiments results the proposed new filter has better performance on different noise variance comparing to the other existing noise removal filters in the experiments. © Wiley Periodicals, Inc.

  7. Development and modelling of a steel slag filter effluent neutralization process with CO2-enriched air from an upstream bioprocess.

    Science.gov (United States)

    Bove, Patricia; Claveau-Mallet, Dominique; Boutet, Étienne; Lida, Félix; Comeau, Yves

    2018-02-01

    The main objective of this project was to develop a steel slag filter effluent neutralization process by acidification with CO 2 -enriched air coming from a bioprocess. Sub-objectives were to evaluate the neutralization capacity of different configurations of neutralization units in lab-scale conditions and to propose a design model of steel slag effluent neutralization. Two lab-scale column neutralization units fed with two different types of influent were operated at hydraulic retention time of 10 h. Tested variables were mode of flow (saturated or percolating), type of media (none, gravel, Bionest and AnoxKaldnes K3), type of air (ambient or CO 2 -enriched) and airflow rate. One neutralization field test (saturated and no media, 2000-5000 ppm CO 2 , sequential feeding, hydraulic retention time of 7.8 h) was conducted for 7 days. Lab-scale and field-scale tests resulted in effluent pH of 7.5-9.5 when the aeration rate was sufficiently high. A model was implemented in the PHREEQC software and was based on the carbonate system, CO 2 transfer and calcite precipitation; and was calibrated on ambient air lab tests. The model was validated with CO 2 -enriched air lab and field tests, providing satisfactory validation results over a wide range of CO 2 concentrations. The flow mode had a major impact on CO 2 transfer and hydraulic efficiency, while the type of media had little influence. The flow mode also had a major impact on the calcite surface concentration in the reactor: it was constant in saturated mode and was increasing in percolating mode. Predictions could be made for different steel slag effluent pH and different operation conditions (hydraulic retention time, CO 2 concentration, media and mode of flow). The pH of the steel slag filter effluent and the CO 2 concentration of the enriched air were factors that influenced most the effluent pH of the neutralization process. An increased concentration in CO 2 in the enriched air reduced calcite precipitation

  8. Filter This

    Directory of Open Access Journals (Sweden)

    Audrey Barbakoff

    2011-03-01

    Full Text Available In the Library with the Lead Pipe welcomes Audrey Barbakoff, a librarian at the Milwaukee Public Library, and Ahniwa Ferrari, Virtual Experience Manager at the Pierce County Library System in Washington, for a point-counterpoint piece on filtering in libraries. The opinions expressed here are those of the authors, and are not endorsed by their employers. [...

  9. Monolithic integrated filters - An overview

    Science.gov (United States)

    Entenmann, W.

    1981-04-01

    An overview of the state of the art in monolithic integrated filter design is given. The close mutual influence of technology and network theory and the continuing development of filter designs with higher integration, higher reliability, lower costs and lower space demands are examined. The fundamental concepts of circuit theory and MOS technology are described and the principal construction of the components of the three major classes of MOS filter circuits examined, namely the change-transfer filter, the switched-capacitor filter and the digital filter. The most important properties, such as the periodicity of the spectra, the impulse response, as well as recursive, nonrecursive, linear and minimal phase filters are covered. Some methods for calculating filter circuits by using classical reactance filter synthesis with the aid of suitable transformations from analog time-continuous reference circuits are discussed. The obtainable signal frequency ranges and filter grades are shown in order to compare the efficiency and operating range of monolithic integrated filter circuits with each other and with other concepts.

  10. Development of a method for bacteria and virus recovery from heating, ventilation, and air conditioning (HVAC) filters.

    Science.gov (United States)

    Farnsworth, James E; Goyal, Sagar M; Kim, Seung Won; Kuehn, Thomas H; Raynor, Peter C; Ramakrishnan, M A; Anantharaman, Senthilvelan; Tang, Weihua

    2006-10-01

    The aim of the work presented here is to study the effectiveness of building air handling units (AHUs) in serving as high volume sampling devices for airborne bacteria and viruses. An HVAC test facility constructed according to ASHRAE Standard 52.2-1999 was used for the controlled loading of HVAC filter media with aerosolized bacteria and virus. Nonpathogenic Bacillus subtilis var. niger was chosen as a surrogate for Bacillus anthracis. Three animal viruses; transmissible gastroenteritis virus (TGEV), avian pneumovirus (APV), and fowlpox virus were chosen as surrogates for three human viruses; SARS coronavirus, respiratory syncytial virus, and smallpox virus; respectively. These bacteria and viruses were nebulized in separate tests and injected into the test duct of the test facility upstream of a MERV 14 filter. SKC Biosamplers upstream and downstream of the test filter served as reference samplers. The collection efficiency of the filter media was calculated to be 96.5 +/- 1.5% for B. subtilis, however no collection efficiency was measured for the viruses as no live virus was ever recovered from the downstream samplers. Filter samples were cut from the test filter and eluted by hand-shaking. An extraction efficiency of 105 +/- 19% was calculated for B. subtilis. The viruses were extracted at much lower efficiencies (0.7-20%). Our results indicate that the airborne concentration of spore-forming bacteria in building AHUs may be determined by analyzing the material collected on HVAC filter media, however culture-based analytical techniques are impractical for virus recovery. Molecular-based identification techniques such as PCR could be used.

  11. Development of an Inner Filter Effects-Based Upconversion Nanoparticles-Curcumin Nanosystem for the Sensitive Sensing of Fluoride Ion.

    Science.gov (United States)

    Liu, Yan; Ouyang, Qin; Li, Huanhuan; Zhang, Zhengzhu; Chen, Quansheng

    2017-05-31

    This paper describes a novel ratiometric fluorescence-based sensor for the detection of fluoride ion. Yb3+, Er3+, and Tm3+ codoped NaYF4 upconversion nanoparticles (UCNPs), which can emit fluorescence at 546, 657, 758, and 812 nm under the 980 nm single wavelength excitation, were synthesized, amino-modified and applied as the fluorescent signal indicator. The natural chemical curcumin served as specific recognition element and mixed with UCNPs to make a nanosystem. In this nanosystem, the absorption peak of curcumin shows a bathochromic shift when F- was added, causing an upconversion fluorescence quenching at 546 and 657 nm through inner filter effects (IFE), whereas the upconversion emission at 758 and 812 nm remained unchanged. Thus, the fluorescence ratio I546/I758 was inversely proportional to F- concentration. Meanwhile, the large absorption bathochromic shift also lead to a color change, based on the colorimetric analysis of F- by the naked eye. Under the optimized conditions, the developed UCNPs-curcumin mixed system achieved the colorimetric and ratiometric fluorescence sensing toward F- in the linear range of 25-200 μM and 5-200 μM, with the detection limits as low as 25 μM (ca. 0.48 ppm) and 5 μM (ca. 0.10 ppm), respectively. The developed nanosystem also has high selectivity and antijamming ability. Furthermore, this method showed promising practical applications in spiked real samples (ex., tap water and milk) with recoveries of 79.58% to 134.02% and RSD values in the range of 0.94% to 22.11%, which confirmed its great potential in harmful substance detection.

  12. Development of an adaptive low-pass filtered speech test for the identification of auditory processing disorders.

    Science.gov (United States)

    O'Beirne, Greg A; McGaffin, Andrew J; Rickard, Natalie A

    2012-06-01

    One type of test commonly used to examine auditory processing disorders (APD) is the low-pass filtered speech test (LPFST), of which there are various versions. In LPFSTs, a monaural, low-redundancy speech sample is distorted by using filtering to modify its frequency content. Due to the richness of the neural pathways in the auditory system and the redundancy of acoustic information in spoken language, a normal listener is able to recognize speech even when parts of the signal are missing, whereas this ability is often impaired in listeners with APD. One limitation of the various versions of the LPFST is that they are carried out using a constant level of low-pass filtering (e.g. a fixed 1kHz corner frequency) which makes them prone to ceiling and floor effects. The purpose of this study was to counter these effects by modifying the LPFST using a computer-based adaptive procedure, and to evaluate the performance of normal-hearing participants of varying ages on the test. In this preliminary study, 33 adults and 30 children (aged 8-11 years) with no known history of listening difficulties were tested. The University of Canterbury Adaptive Speech Test (UCAST) platform was used to administer a four-alternative forced-choice adaptive test that altered a low-pass filter (LPF) to track the corner frequency at which participants correctly identified a certain percentage of the word stimuli. Findings on the University of Canterbury Adaptive Speech Test-Filtered Words (UCAST-FW) indicated a significant maturational effect. Adult participants performed significantly better on the UCAST-FW in comparison to the child participants. The UCAST-FW test was reliable over repeated administrations. An adaptive low-pass filtered speech test such as the UCAST-FW is sensitive to maturational changes in auditory processing ability. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  13. Water Filter

    Science.gov (United States)

    1982-01-01

    A compact, lightweight electrolytic water sterilizer available through Ambassador Marketing, generates silver ions in concentrations of 50 to 100 parts per billion in water flow system. The silver ions serve as an effective bactericide/deodorizer. Tap water passes through filtering element of silver that has been chemically plated onto activated carbon. The silver inhibits bacterial growth and the activated carbon removes objectionable tastes and odors caused by addition of chlorine and other chemicals in municipal water supply. The three models available are a kitchen unit, a "Tourister" unit for portable use while traveling and a refrigerator unit that attaches to the ice cube water line. A filter will treat 5,000 to 10,000 gallons of water.

  14. Development of a Kalman Filter in the Gauss-Helmert Model for Reliability Analysis in Orientation Determination with Smartphone Sensors.

    Science.gov (United States)

    Ettlinger, Andreas; Neuner, Hans; Burgess, Thomas

    2018-01-31

    The topic of indoor positioning and indoor navigation by using observations from smartphone sensors is very challenging as the determined trajectories can be subject to significant deviations compared to the route travelled in reality. Especially the calculation of the direction of movement is the critical part of pedestrian positioning approaches such as Pedestrian Dead Reckoning ("PDR"). Due to distinct systematic effects in filtered trajectories, it can be assumed that there are systematic deviations present in the observations from smartphone sensors. This article has two aims: one is to enable the estimation of partial redundancies for each observation as well as for observation groups. Partial redundancies are a measure for the reliability indicating how well systematic deviations can be detected in single observations used in PDR. The second aim is to analyze the behavior of partial redundancy by modifying the stochastic and functional model of the Kalman filter. The equations relating the observations to the orientation are condition equations, which do not exhibit the typical structure of the Gauss-Markov model ("GMM"), wherein the observations are linear and can be formulated as functions of the states. To calculate and analyze the partial redundancy of the observations from smartphone-sensors used in PDR, the system equation and the measurement equation of a Kalman filter as well as the redundancy matrix need to be derived in the Gauss-Helmert model ("GHM"). These derivations are introduced in this article and lead to a novel Kalman filter structure based on condition equations, enabling reliability assessment of each observation.

  15. Leukodepletion blood filters: filter design and mechanisms of leukocyte removal.

    Science.gov (United States)

    Dzik, S

    1993-04-01

    Modern leukocyte removal filters have been developed after years of refinement in design. Current filters are composite filters in which synthetic microfiber material is prepared as a nonwoven web. The filter material may be surface modified to alter surface tension or charge to improve performance. The housing design promotes effective contact of blood with the filter material and decreases shear forces. The exact mechanisms by which these filters remove leukocytes from blood components are uncertain, but likely represent a combination of both physical and biological processes whose contributions to leukocyte removal are interdependent. Small-pore microfiber webs result in barrier phenomena that permit retention of individual cells and increase the total adsorptive area of the filter. Modifications in surface charge can increase or decrease cell attraction to the fibers. Optimum interfacial surface tensions between blood cells, plasma, and filter fibers not only permit effective blood flow through small fiber pores, but also facilitate cell contact with the material. Barrier retention is a common mechanism for all modern leukocyte-removal filters and applies to all leukocyte subtypes. Because barrier retention does not depend on cell viability, it is operative for cells of any age and will retain any nondeformable cell, including whole nuclei from lymphocytes or monocytes. Barrier retention is supplemented by retention by adhesion. RBCs, lymphocytes, monocytes, granulocytes, and platelets differ in their relative adhesiveness to filter fibers. Different adhesive mechanisms are used in filters designed for RBCs compared with filters designed for platelets. Although lymphocytes, monocytes, and granulocytes can adhere directly to filter fibers, the biological mechanisms underlying cell adhesion may differ for these cell types. These differences may depend on expression of cell adhesion molecules. In the case of filtration of fresh RBCs, platelet-leukocyte interaction

  16. The intractable cigarette 'filter problem'.

    Science.gov (United States)

    Harris, Bradford

    2011-05-01

    When lung cancer fears emerged in the 1950s, cigarette companies initiated a shift in cigarette design from unfiltered to filtered cigarettes. Both the ineffectiveness of cigarette filters and the tobacco industry's misleading marketing of the benefits of filtered cigarettes have been well documented. However, during the 1950s and 1960s, American cigarette companies spent millions of dollars to solve what the industry identified as the 'filter problem'. These extensive filter research and development efforts suggest a phase of genuine optimism among cigarette designers that cigarette filters could be engineered to mitigate the health hazards of smoking. This paper explores the early history of cigarette filter research and development in order to elucidate why and when seemingly sincere filter engineering efforts devolved into manipulations in cigarette design to sustain cigarette marketing and mitigate consumers' concerns about the health consequences of smoking. Relevant word and phrase searches were conducted in the Legacy Tobacco Documents Library online database, Google Patents, and media and medical databases including ProQuest, JSTOR, Medline and PubMed. 13 tobacco industry documents were identified that track prominent developments involved in what the industry referred to as the 'filter problem'. These reveal a period of intense focus on the 'filter problem' that persisted from the mid-1950s to the mid-1960s, featuring collaborations between cigarette producers and large American chemical and textile companies to develop effective filters. In addition, the documents reveal how cigarette filter researchers' growing scientific knowledge of smoke chemistry led to increasing recognition that filters were unlikely to offer significant health protection. One of the primary concerns of cigarette producers was to design cigarette filters that could be economically incorporated into the massive scale of cigarette production. The synthetic plastic cellulose acetate

  17. Thin-film optical pass band filters based on new photo-lithographic process for CaSSIS FPA detector on Exomars TGO mission: development, integration, and test

    Science.gov (United States)

    Gambicorti, L.; Piazza, D.; Gerber, M.; Pommerol, A.; Roloff, V.; Ziethe, R.; Zimmermann, C.; Da Deppo, V.; Cremonese, G.; Ficai Veltroni, I.; Marinai, M.; Di Carmine, E.; Bauer, T.; Moebius, P.; Thomas, N.

    2016-08-01

    A new technique based on photolithographic processes of thin-film optical pass band coatings on a monolithic substrate has been applied to the filters of the Focal Plane Assembly (FPA) of the Colour and Stereo Surface Imaging System (CaSSIS) that will fly onboard of the ExoMars Trace Gas Orbiter to be launched in March 2016 by ESA. The FPA including is one of the spare components of the Simbio-Sys instrument of the Italian Space Agency (ASI) that will fly on ESA's Bepi Colombo mission to Mercury. The detector, developed by Raytheon Vision Systems, is a 2kx2k hybrid Si-PIN array with a 10 μm pixel. The detector is housed within a block and has filters deposited directly on the entrance window. The window is a 1 mm thick monolithic plate of fused silica. The Filter Strip Assembly (FSA) is produced by Optics Balzers Jena GmbH and integrated on the focal plane by Leonardo-Finmeccanica SpA (under TAS-I responsibility). It is based on dielectric multilayer interference coatings, 4 colour bands selected with average in-band transmission greater than 95 percent within wavelength range (400-1100 nm), giving multispectral images on the same detector and thus allows CaSSIS to operate in push-frame mode. The Field of View (FOV) of each colour band on the detector is surrounded by a mask of low reflective chromium (LRC), which also provides with the straylight suppression required (an out-of-band transmission of less than 10-5/nm). The mask has been shown to deal effectively with cross-talk from multiple reflections between the detector surface and the filter. This paper shows the manufacturing and optical properties of the FSA filters and the FPA preliminary on-ground calibration results.

  18. Development of serum-free media for the cultivation and recovery of Acholeplasma laidlawii used for challenge testing sterilizing-grade filters in biopharmaceutical applications.

    Science.gov (United States)

    Bates, Shawn; Nguyen, Nhung; Lentine, Kerry Roche

    2008-01-01

    A serum-free cultivation broth and recovery agar for use in 0.1 micron-rated filter characterization and validation studies for biopharmaceutical applications were developed using Acholeplasma laidlawii as the test microorganism. Selection criteria were (A) a single-stage, serum-free broth medium to support high-titer cell growth and yield a cellular morphology suitable for bacterial challenge testing within 24 h and (B) a serum-free agar growth medium that can recover cells using conventional enumeration techniques. Different formulation components at various concentrations were screened for their effects on growth, cell size, and recovery on membrane filters. An optimized broth, Glucose Hydrolysate Broth, containing glucose, polypeptone, bovine serum albumin, 2-Amino-2-(hydroxymethyl)-1,3-propanediol (Tris base), oleic acid, and palmitic acid produced small 370 X 406 nanometer monodisperse cells at titers in excess of 1 x 10(9) colony-forming units per milliliter (cfu mL(-1)) within 20-24 h of incubation. Glucose Mycoplasma Agar, containing glucose, mycoplasma broth base, bovine serum albumin, Tris base, oleic acid, and palmitic acid, produced colonies approximately 1 mm in size and facilitated recovery on 0.2-microm polyvinylidene fluoride membrane filters. A comparison of recovery of A. laidlawii on Glucose Mycoplasma Agar pour-plate versus membrane filters resulted in an 89 +/- 4% recovery. Linearity across the target recovery range was 0.9992 (r2). Presence/absence tests of filtrate from each 0.2-microm assay membrane resulted in absence of growth as compared to controls, thus demonstrating the suitability of using 0.2-microm membrane filters for recovery of A. laidlawii.

  19. Multilevel Mixture Kalman Filter

    Directory of Open Access Journals (Sweden)

    Xiaodong Wang

    2004-11-01

    Full Text Available The mixture Kalman filter is a general sequential Monte Carlo technique for conditional linear dynamic systems. It generates samples of some indicator variables recursively based on sequential importance sampling (SIS and integrates out the linear and Gaussian state variables conditioned on these indicators. Due to the marginalization process, the complexity of the mixture Kalman filter is quite high if the dimension of the indicator sampling space is high. In this paper, we address this difficulty by developing a new Monte Carlo sampling scheme, namely, the multilevel mixture Kalman filter. The basic idea is to make use of the multilevel or hierarchical structure of the space from which the indicator variables take values. That is, we draw samples in a multilevel fashion, beginning with sampling from the highest-level sampling space and then draw samples from the associate subspace of the newly drawn samples in a lower-level sampling space, until reaching the desired sampling space. Such a multilevel sampling scheme can be used in conjunction with the delayed estimation method, such as the delayed-sample method, resulting in delayed multilevel mixture Kalman filter. Examples in wireless communication, specifically the coherent and noncoherent 16-QAM over flat-fading channels, are provided to demonstrate the performance of the proposed multilevel mixture Kalman filter.

  20. Digital filters

    CERN Document Server

    Hamming, Richard W

    1997-01-01

    Digital signals occur in an increasing number of applications: in telephone communications; in radio, television, and stereo sound systems; and in spacecraft transmissions, to name just a few. This introductory text examines digital filtering, the processes of smoothing, predicting, differentiating, integrating, and separating signals, as well as the removal of noise from a signal. The processes bear particular relevance to computer applications, one of the focuses of this book.Readers will find Hamming's analysis accessible and engaging, in recognition of the fact that many people with the s

  1. Filtered or Unfiltered?

    Science.gov (United States)

    Curry, Ann; Haycock, Ken

    2001-01-01

    Discusses results of a survey questionnaire of public and school libraries that investigated the use of Internet filtering software. Considers filter alternatives; reasons for filtering or not filtering; brand names; satisfaction with site blocking; satisfaction with the decision to install filter software; and guidelines for considering filters.…

  2. Stack filter classifiers

    Energy Technology Data Exchange (ETDEWEB)

    Porter, Reid B [Los Alamos National Laboratory; Hush, Don [Los Alamos National Laboratory

    2009-01-01

    Just as linear models generalize the sample mean and weighted average, weighted order statistic models generalize the sample median and weighted median. This analogy can be continued informally to generalized additive modeels in the case of the mean, and Stack Filters in the case of the median. Both of these model classes have been extensively studied for signal and image processing but it is surprising to find that for pattern classification, their treatment has been significantly one sided. Generalized additive models are now a major tool in pattern classification and many different learning algorithms have been developed to fit model parameters to finite data. However Stack Filters remain largely confined to signal and image processing and learning algorithms for classification are yet to be seen. This paper is a step towards Stack Filter Classifiers and it shows that the approach is interesting from both a theoretical and a practical perspective.

  3. Development of a new ridge filter with honeycomb geometry for a pencil beam scanning system in particle radiotherapy

    Science.gov (United States)

    Tansho, R.; Furukawa, T.; Hara, Y.; Mizushima, K.; Saotome, N.; Saraya, Y.; Shirai, T.; Noda, K.

    2017-09-01

    A ridge filter (RGF), a beam energy modulation device, is usually used for particle radiotherapy with a pencil beam scanning system. The conventional RGF has a one-dimensional (1D) periodic laterally stepped structure in orthogonal plane with a central beam direction. The energy of a beam passing through the different thicknesses of the stepped RGF is modulated. Although the lateral pencil beam size is required to cover the several stepped RGF units to modulate its energy as designed, the current trend is to decrease lateral beam size to improve the scanning system. As a result, the beam size becomes smaller than the size of the individual RGF unit. The aim of this study was to develop a new RGF with two-dimensional (2D) honeycomb geometry to simultaneously achieve both a decrease in lateral beam size and the desired energy modulation. The conventional 1D-RGF and the 2D-RGF with honeycomb geometry were both designed so that the Bragg peak size of a 79 MeV/u carbon ion pencil beam in water was 1 mm RMS in the beam direction. To validate the design of the 2D-RGF, we calculated depth dose distributions in water using a simplified Monte Carlo method. In the calculations, we decreased the lateral pencil beam size at the entrance of the RGF and investigated the threshold of lateral beam size with which the pencil beam can reproduce the desired Bragg peak size for each type of RGF. In addition, we calculated lateral dose distributions in air downstream from the RGF and evaluated the inhomogeneity of the lateral dose distributions. Using the 2D-RGF, the threshold of lateral beam size with which the pencil beam can reproduce the desired Bragg peak size was smaller than that using the 1D-RGF. Moreover, the distance from the RGF at which the lateral dose distribution becomes uniform was shorter using the 2D-RGF than that using the 1D-RGF. These results indicate that when the periodic length of both RGFs is the same, the 2D-RGF allows use of a pencil beam with smaller lateral

  4. Gaussian particle flow implementation of PHD filter

    Science.gov (United States)

    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.

  5. Development of highly sensitive passive sampler for nitrogen dioxide using porous polyethylene membrane filter as turbulence limiting diffuser

    Science.gov (United States)

    Sekine, Yoshika; Watts, Simon F.; Rendell, Andrew; Butsugan, Michio

    2008-06-01

    A new design of passive sampler is described which is appropriate to reduce the sampling resolution of most formats of Palmes' tubes from weeks to 24 h or less. The sampler employs a flat-type porous polyethylene membrane filter as a diffuser, which controls mass transfer of the target analyte from ambient air to impregnated trapping filter. The new design is applicable to any analyte for which there is a paper Palmes' tube method, e.g. H2S, OCS, NO, SO2, O3, organic acids, NH3 and so on. As an example, the sampler for the determination of ambient atmospheric nitrogen dioxide (NO2), employing a trapping filter impregnated with triethanolamine is described. Performance of the new sampler was evaluated in laboratory and field experiments. The sampling rate was measured directly at four kerb-side sites in Oxford, UK and Kanagawa, Japan, by comparing measured concentrations from the samplers with co-located automated NO2 analyzers. Results showed mass transfer rate of NO2 within the diffuser did not change with external wind speed (0.5-2 m s-1). The passive device had relatively higher sampling rate than those of previous samplers and gave equivalent results on NO2 concentrations to the automated NO2 analyzer at 24 h or less sampling duration. LOD and LOQ indicated possible application of these devices to sampling in urban intermediate, urban background and suburban areas.

  6. Tunable Multiband Microwave Photonic Filters

    Directory of Open Access Journals (Sweden)

    Mable P. Fok

    2017-11-01

    Full Text Available The increasing demand for multifunctional devices, the use of cognitive wireless technology to solve the frequency resource shortage problem, as well as the capabilities and operational flexibility necessary to meet ever-changing environment result in an urgent need of multiband wireless communications. Spectral filter is an essential part of any communication systems, and in the case of multiband wireless communications, tunable multiband RF filters are required for channel selection, noise/interference removal, and RF signal processing. Unfortunately, it is difficult for RF electronics to achieve both tunable and multiband spectral filtering. Recent advancements of microwave photonics have proven itself to be a promising candidate to solve various challenges in RF electronics including spectral filtering, however, the development of multiband microwave photonic filtering still faces lots of difficulties, due to the limited scalability and tunability of existing microwave photonic schemes. In this review paper, we first discuss the challenges that were facing by multiband microwave photonic filter, then we review recent techniques that have been developed to tackle the challenge and lead to promising developments of tunable microwave photonic multiband filters. The successful design and implementation of tunable microwave photonic multiband filter facilitate the vision of dynamic multiband wireless communications and radio frequency signal processing for commercial, defense, and civilian applications.

  7. Power systems development facility. Quarterly technical progress report, July 1--September 30, 1993

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-31

    This quarterly technical progress report summarizes work completed during the Second Quarter of the Second Budget Period, July 1 through September 30, 1993, under the Department of Energy (DOE) Cooperative Agreement No. DE-FC21-90MC25140 entitled ``Hot Gas Cleanup Test Facility for Gasification and Pressurized Combustion.`` The objective of this project is to evaluate hot gas particle control technologies using coal-derived gas streams. This will entail the design, construction, installation, and use of a flexible test facility which can operate under realistic gasification and combustion conditions. The major particulate control device issues to be addressed include the integration of the particulate control devices into coal utilization systems, on-line cleaning techniques, chemical and thermal degradation of components, fatigue or structural failures, blinding, collection efficiency as a function of particle size, and scaleup of particulate control systems to commercial size. The conceptual design of the facility was extended to include a within scope, phased expansion of the existing Hot Gas Cleanup Test Facility Cooperative Agreement to also address systems integration issues of hot particulate removal in advanced coal-based power generation systems. This expansion included the consideration of the following modules at the test facility in addition to the existing Transport Reactor gas source and Hot Gas Cleanup Units: Carbonizer/Pressurized Circulating Fluidized Bed Gas Source. Hot Gas Cleanup Units to mate to all gas streams; Combustion Gas Turbine; and Fuel Cell and associated gas treatment. This expansion to the Hot Gas Cleanup Test Facility is herein referred to as the Power Systems Development Facility (PSDF). The major emphasis during this reporting period was continuing the detailed design of the facility.

  8. Structured filtering

    Science.gov (United States)

    Granade, Christopher; Wiebe, Nathan

    2017-08-01

    A major challenge facing existing sequential Monte Carlo methods for parameter estimation in physics stems from the inability of existing approaches to robustly deal with experiments that have different mechanisms that yield the results with equivalent probability. We address this problem here by proposing a form of particle filtering that clusters the particles that comprise the sequential Monte Carlo approximation to the posterior before applying a resampler. Through a new graphical approach to thinking about such models, we are able to devise an artificial-intelligence based strategy that automatically learns the shape and number of the clusters in the support of the posterior. We demonstrate the power of our approach by applying it to randomized gap estimation and a form of low circuit-depth phase estimation where existing methods from the physics literature either exhibit much worse performance or even fail completely.

  9. Concept and development of a discharge alert filter for abnormal laboratory values coupled with computerized provider order entry: a tool for quality improvement and hospital risk management.

    Science.gov (United States)

    Mathew, George; Kho, Abel; Dexter, Paul; Bloodworth, Nathaniel; Fantz, Corinne; Spell, Nathan; LaBorde, David V

    2012-06-01

    To develop a clinical decision support system activated at the time of discharge to reduce potentially inappropriate discharges from unidentified or unaddressed abnormal laboratory values. We identified 106 laboratory tests for possible inclusion in the discharge alert filter. We selected 7 labs as widely available, commonly obtained, and associated with high risk for potential morbidity or mortality within abnormal ranges. We identified trigger thresholds at levels that would capture significant laboratory abnormalities while avoiding excessive flag generation because of laboratory results that minimally deviate outside the normal reference range. We selected sodium (>155 or 6 mEq/dL) phosphorous (11,000 cells/mm with a rise of 20% or more between the 2 most recent results), and international normalized ratio greater than 4. A discharge alert filter that reliably and effectively identifies patients that may be discharged in unsafe situations because of unaddressed critical laboratory values can improve patient safety at discharge and potentially reduce the incidence of costly litigation. Further research is needed to validate whether the proposed discharge alert filter is effective at improving patient safety at discharge.

  10. DRUCKFLAMM - Investigation on combustion and hot gas cleanup in pulverized coal combustion systems. Final report; DRUCKFLAMM - Untersuchungen zur Verbrennung und Heissgasreinigung bei der Druckkohlenstaubfeuerung. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Hein, K.R.G.; Benoehr, A.; Schuermann, H.; Stroehle, J.; Klaiber, C.; Kuhn, R.; Maier, J.; Schnell, U.; Unterberger, S.

    2001-07-01

    The ambitions of making energy supply more efficient and less polluting brought forth the development of coal based combined cycle power plants allowing considerable increases in net efficiencies. One of the regarded firing concepts for a coal based combined cycle power plant is represented by the pressurised pulverised coal combustion process which has the highest efficiency potential compared with the other coal based concepts. The fundamental purpose of the project was to gain firm knowledge concerning firing behaviour of coal in a pressurised pulverised coal combustion system. Detailed investigations were carried out in a pressurised entrained flow reactor taking into account fuel conversion and particle behaviour, pollutant formation and material behaviour under conditions of a pressurised pulverised coal firing. During the project's investigations several different measurement techniques were tested and partially also acquired (e.g. a two-colour-pyrometry system to measure simultaneous particle surface temperature and particle diameter of burning fuel particles). Calculation models under pressurised conditions for pressure vessel simulation and better scale-up were developed synchronously with the experimental investigations. The results gained using the pressurised entrained flow reactor show that many combustion mechanisms are influenced by increased pressure, for instance the fuel conversion is intensified and at the same time pollutant emissions decreased. The material investigations show that the ceramic materials used due to the very high combustion temperatures are very sensitive versus slagging and fast temperature changes, therefore further development requirements are needed to fully realise the high durability of ceramics in the pressurised furnace. Concerning the improvement of existing models for furnace simulation under pressurised conditions, a good resemblance can be observed when considering the actual measurement results from the test

  11. Experiences with sol-gel bonded high porosity alumina fiber materials for filter applications

    OpenAIRE

    Handrick, Karin E.; Mohlratzer, August; Ostertag, Rolf; Sporn, Dieter; Schmidt, Helmut K.

    1988-01-01

    High porous alumina fiber structures appear promising for hot gas filtration in particular for diesel particulate traps. For this purpose, however, a method is required for manufacturing of stable shapes resisant to the blow-out by the gas flow. The sol-gel process was expected to be the best suited method for fiber bonding to provide the required stability. The main tasks of the development-work were a uniform isotropic fiber-distribution, the adaptation of the sol-gel-process to the applica...

  12. Convergent Filter Bases

    Directory of Open Access Journals (Sweden)

    Coghetto Roland

    2015-09-01

    Full Text Available We are inspired by the work of Henri Cartan [16], Bourbaki [10] (TG. I Filtres and Claude Wagschal [34]. We define the base of filter, image filter, convergent filter bases, limit filter and the filter base of tails (fr: filtre des sections.

  13. Ageing studies for the ATLAS MDT muonchambers and development of a gas filter to prevent drift tube ageing

    Energy Technology Data Exchange (ETDEWEB)

    Koenig, S.

    2008-01-15

    The muon spectrometer of the ATLAS detector, which is currently assembled at the LHC accelerator at CERN, uses drift tubes as basic detection elements over most of the solid angle. The performance of these monitored drift tubes (MDTs), in particular their spatial resolution of 80 {mu}m, determines the precision of the spectrometer. If ageing effects occur, the precision of the drift tubes will be degraded. Hence ageing effects have to be minimized or avoided altogether if possible. Even with a gas mixture of Ar:CO{sub 2}=93:7, which was selected for its good ageing properties, ageing effects were observed in test systems. They were caused by small amounts of impurities, in particular volatile silicon compounds. Systematic studies revealed the required impurity levels deteriorating the drift tubes to be well below 1 ppm. Many components of the ATLAS MDT gas system are supplied by industry. In a newly designed ageing experiment in Freiburg these components were validated for their use in ATLAS. With a fully assembled ATLAS gas distribution rack as test component ageing effects were observed. It was therefore decided to install gas filters in the gas distribution lines to remove volatile silicon compounds efficiently from the gas mixture. Finally a filter was designed that can adsorb up to 5.5 g of volatile silicon compounds, hereby reducing the impurities in the outlet gas mixture to less than 30 ppb. (orig.)

  14. Ceramic HEPA Filter Program

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, M A; Bergman, W; Haslam, J; Brown, E P; Sawyer, S; Beaulieu, R; Althouse, P; Meike, A

    2012-04-30

    Potential benefits of ceramic filters in nuclear facilities: (1) Short term benefit for DOE, NRC, and industry - (a) CalPoly HTTU provides unique testing capability to answer questions for DOE - High temperature testing of materials, components, filter, (b) Several DNFSB correspondences and presentations by DNFSB members have highlighted the need for HEPA filter R and D - DNFSB Recommendation 2009-2 highlighted a nuclear facility response to an evaluation basis earthquake followed by a fire (aka shake-n-bake) and CalPoly has capability for a shake-n-bake test; (2) Intermediate term benefit for DOE and industry - (a) Filtration for specialty applications, e.g., explosive applications at Nevada, (b) Spin-off technologies applicable to other commercial industries; and (3) Long term benefit for DOE, NRC, and industry - (a) Across industry, strong desire for better performance filter, (b) Engineering solution to safety problem will improve facility safety and decrease dependence on associated support systems, (c) Large potential life-cycle cost savings, and (d) Facilitates development and deployment of LLNL process innovations to allow continuous ventilation system operation during a fire.

  15. z-transform DFT filters and FFT's

    DEFF Research Database (Denmark)

    Bruun, G.

    1978-01-01

    The paper shows how discrete Fourier transformation can be implemented as a filter bank in a way which reduces the number of filter coefficients. A particular implementation of such a filter bank is directly related to the normal complex FFT algorithm. The principle developed further leads to typ...

  16. Distortion invariant pattern recognition with phase filters

    Science.gov (United States)

    Rosen, Joseph; Shamir, Joseph

    1987-01-01

    A recently developed approach for pattern recognition using spatial filters with reduced tolerance requirements is employed for the generation of filters containing mainly phase information. As anticipated, the recognition levels were decreased, but they remain adequate for unambiguous identification together with appreciable amounts of distortion immunity. Furthermore, the information content of the filters is compatible with low devices like spatial light modulators.

  17. Matched Spectral Filter Imager Project

    Data.gov (United States)

    National Aeronautics and Space Administration — OPTRA proposes the development of an imaging spectrometer for greenhouse gas and volcanic gas imaging based on matched spectral filtering and compressive imaging....

  18. Integrated Spatial Filter Array Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To address the NASA Earth Science Division need for spatial filter arrays for amplitude and wavefront control, Luminit proposes to develop a novel Integrated Spatial...

  19. Power Systems Development Facility Gasification Test Campaing TC18

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services

    2005-08-31

    In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama, routinely demonstrates gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a KBR Transport Gasifier, a hot gas particulate control device (PCD), advanced syngas cleanup systems, and high pressure solids handling systems. This report details Test Campaign TC18 of the PSDF gasification process. Test campaign TC18 began on June 23, 2005, and ended on August 22, 2005, with the gasifier train accumulating 1,342 hours of operation using Powder River Basin (PRB) subbituminous coal. Some of the testing conducted included commissioning of a new recycle syngas compressor for gasifier aeration, evaluation of PCD filter elements and failsafes, testing of gas cleanup technologies, and further evaluation of solids handling equipment. At the conclusion of TC18, the PSDF gasification process had been operated for more than 7,750 hours.

  20. Optimal Gaussian Filter for Effective Noise Filtering

    OpenAIRE

    Kopparapu, Sunil; Satish, M

    2014-01-01

    In this paper we show that the knowledge of noise statistics contaminating a signal can be effectively used to choose an optimal Gaussian filter to eliminate noise. Very specifically, we show that the additive white Gaussian noise (AWGN) contaminating a signal can be filtered best by using a Gaussian filter of specific characteristics. The design of the Gaussian filter bears relationship with the noise statistics and also some basic information about the signal. We first derive a relationship...

  1. POWER SYSTEMS DEVELOPMENT FACILITY

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2002-11-01

    This report discusses test campaign GCT4 of the Kellogg Brown & Root, Inc. (KBR) transport reactor train with a Siemens Westinghouse Power Corporation (Siemens Westinghouse) particle filter system at the Power Systems Development Facility (PSDF) located in Wilsonville, Alabama. The transport reactor is an advanced circulating fluidized-bed reactor designed to operate as either a combustor or a gasifier using one of two possible particulate control devices (PCDs). The transport reactor was operated as a pressurized gasifier during GCT4. GCT4 was planned as a 250-hour test run to continue characterization of the transport reactor using a blend of several Powder River Basin (PRB) coals and Bucyrus limestone from Ohio. The primary test objectives were: Operational Stability--Characterize reactor loop and PCD operations with short-term tests by varying coal-feed rate, air/coal ratio, riser velocity, solids-circulation rate, system pressure, and air distribution. Secondary objectives included the following: Reactor Operations--Study the devolatilization and tar cracking effects from transient conditions during transition from start-up burner to coal. Evaluate the effect of process operations on heat release, heat transfer, and accelerated fuel particle heat-up rates. Study the effect of changes in reactor conditions on transient temperature profiles, pressure balance, and product gas composition. Effects of Reactor Conditions on Synthesis Gas Composition--Evaluate the effect of air distribution, steam/coal ratio, solids-circulation rate, and reactor temperature on CO/CO{sub 2} ratio, synthesis gas Lower Heating Value (LHV), carbon conversion, and cold and hot gas efficiencies. Research Triangle Institute (RTI) Direct Sulfur Recovery Process (DSRP) Testing--Provide syngas in support of the DSRP commissioning. Loop Seal Operations--Optimize loop seal operations and investigate increases to previously achieved maximum solids-circulation rate.

  2. Development of an all-sky-scanning spectroradiometer with a visible diode array and a near-infrared acousto-optic tunable filter.

    Science.gov (United States)

    Nield, K M; Bittar, A; Hamlin, J D

    1997-10-20

    A sky scanner was developed that collects spectral radiance data over the wavelength range 390-1732 nm by use of two radiometers, the first being a monochromator with a 512-element silicon diode array and the second being a near-infrared acousto-optic tunable filter (AOTF) coupled to an InGaAs detector. The scanner is capable of completing a set of spectral radiance measurements at 146 points in the sky hemisphere in a period of less than 4 min.

  3. Hot Gas Corrosion of Silicon Based Ceramics.

    Science.gov (United States)

    1985-12-13

    results, it must be noted that this is merely because thermodynamic data was unavailable for the beta form. The data generated also indicates that -8% of...N4 will be transformed to SiO 2 (in the form of quartz or cristobalite ) or silicon oxy nitride (Si2 N2 0). While the presence of Si 2 N2 0 has been

  4. Sorbent for use in hot gas desulfurization

    Science.gov (United States)

    Gasper-Galvin, Lee D.; Atimtay, Aysel T.

    1993-01-01

    A multiple metal oxide sorbent supported on a zeolite of substantially silicon oxide is used for the desulfurization of process gas streams, such as from a coal gasifier, at temperatures in the range of about 1200.degree. to about 1600.degree. F. The sorbent is provided by a mixture of copper oxide and manganese oxide and preferably such a mixture with molybdenum oxide. The manganese oxide and the molybdenum are believed to function as promoters for the reaction of hydrogen sulfide with copper oxide. Also, the manganese oxide inhibits the volatilization of the molybdenum oxide at the higher temperatures.

  5. Catalytic hot gas cleaning of gasification gas

    Energy Technology Data Exchange (ETDEWEB)

    Simell, P. [VTT Energy, Espoo (Finland). Energy Production Technologies

    1997-12-31

    The aim of this work was to study the catalytic cleaning of gasification gas from tars and ammonia. In addition, factors influencing catalytic activity in industrial applications were studied, as well as the effects of different operation conditions and limits. Also the catalytic reactions of tar and ammonia with gasification gas components were studied. The activities of different catalyst materials were measured with laboratory-scale reactors fed by slip streams taken from updraft and fluid bed gasifiers. Carbonate rocks and nickel catalysts proved to be active tar decomposing catalysts. Ammonia decomposition was in turn facilitated by nickel catalysts and iron materials like iron sinter and iron dolomite. Temperatures over 850 deg C were required at 2000{sup -1} space velocity at ambient pressure to achieve almost complete conversions. During catalytic reactions H{sub 2} and CO were formed and H{sub 2}O was consumed in addition to decomposing hydrocarbons and ammonia. Equilibrium gas composition was almost achieved with nickel catalysts at 900 deg C. No deactivation by H{sub 2}S or carbon took place in these conditions. Catalyst blocking by particulates was avoided by using a monolith type of catalyst. The apparent first order kinetic parameters were determined for the most active materials. The activities of dolomite, nickel catalyst and reference materials were measured in different gas atmospheres using laboratory apparatus. This consisted of nitrogen carrier, toluene as tar model compound, ammonia and one of the components H{sub 2}, H{sub 2}O, CO, CO{sub 2}, CO{sub 2}+H{sub 2}O or CO+CO{sub 2}. Also synthetic gasification gas was used. With the dolomite and nickel catalyst the highest toluene decomposition rates were measured with CO{sub 2} and H{sub 2}O. In gasification gas, however, the rate was retarded due to inhibition by reaction products (CO, H{sub 2}, CO{sub 2}). Tar decomposition over dolomite was modelled by benzene reactions with CO{sub 2}, H{sub 2}O and gasification gas. Operation conditions free of external or internal mass transfer limitations were used. Apparent first order kinetic parameters were determined for all the studied gas mixtures. In addition, for the CO{sub 2} reaction, a mechanistic model of Langmuir-Hinshelwood type was derived and tested. The best mode was based on benzene single site adsorption as the rate determining step and non-dissociable adsorption of CO{sub 2}. To be active in gasification gas carbonate rocks have to be in a calcined state. When the catalyst was carbonated and water was present, the activity of the catalysts was lost almost completely. This decline of activity closely followed the equilibrium decomposition pressure and temperature of CaCO{sub 3}. (orig.) 56 refs.

  6. Numerical simulation of the porous filter properties for the internal arc mollifying effects

    Energy Technology Data Exchange (ETDEWEB)

    Rochette, D.; Bussiere, W. [Laboratoire Arc Electrique et Plasmas thermiques, CNRS FRE 3120, Universite, Blaise Pascal, IUT de Montlucon, Avenue Aristide Briand, BP 2235, 03101, Montlucon Cedex (France); Clain, S. [Institut de Mathematiques, CNRS UMR 5219, Universite Paul Sabatier Toulouse, 3, 118 route de Narbonne, F-31062 Toulouse Cedex 4 (France); Gentils, F.; Wild, J. [Schneider Electric - Science and Technology Division - Research Center A2, 38050, Grenoble Cedex 9 (France)

    2011-01-15

    A mathematical model and numerical experiments of pressure wave impacts with a porous medium are presented to simulate the valve burst out of a medium voltage switchgear and to evaluate the protection filter efficiency. A simplified one-dimensional gas flow model in porous medium with variable porosity is used. To solve numerically the governing equations, we employed the numerical method presented in Rochette et al. (2005) to take into account the non-conservative term P({partial_derivative}{phi}/{partial_derivative}x). Three sets of test are performed to study several filter prototypes. The objective is to provide a filter which does not produce a high reflected wave and cools enough the ejected hot gas. We first consider filters with variable porosity and simulate the interaction with an incident pressure wave, then we consider two types of granular material to characterize their incidence on the flow and finally, we simulate two different fluid flows (air and SF6) going through the porous medium. (author)

  7. Interdigital filter design

    CSIR Research Space (South Africa)

    Du Plessis, WP

    2009-10-01

    Full Text Available flexible, and allows design tradeoffs to be evaluated in an intuitive way. Keywords: Cavity resonator filters, microwave filters, coupled transmission lines. 1 Introduction Interdigital filters are popular at the higher microwave frequencies for a... number of reasons. Ideal interdigital filters have perfect symmetry which means that they have better phase and delay characteristics than combline filters [1]. The couplings between the resonators of interdigital filters are also lower than those...

  8. Development of an Intrinsic Continuum Robot and Attitude Estimation of Its End-effector Based on a Kalman Filter

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Chang Hyun; Bae, Ji Hwan; Kang, Bong Soo [Hannam University, Daejeon (Korea, Republic of)

    2015-04-15

    This paper presents the design concept of an intrinsic continuum robot for safe man-machine interface and characteristic behaviors of its end-effector based on real experiments. Since pneumatic artificial muscles having similar antagonistic actuation to human muscles are used for main backbones of the proposed robot as well as in the role of the actuating devices, variable stiffness of robotic joints can be available in the actual environment. In order to solve the inherent shortcoming of an intrinsic continuum robot due to bending motion of the backbone materials, a Kalman filter scheme based on a triaxial accelerometer and a triaxial gyroscope was proposed to conduct an attitude estimation of the end-effector of the robot. The experimental results verified that the proposed method was effective in estimating the attitude of the end-effector of the intrinsic continuum robot.

  9. Optional inferior vena caval filters: where are we now?

    LENUS (Irish Health Repository)

    Keeling, A N

    2008-08-01

    With the advent of newer optional\\/retrievable inferior vena caval filters, there has been a rise in the number of filters inserted globally. This review article examines the currently available approved optional filter models, outlines the clinical indications for filter insertion and examines the expanding indications. Additionally, the available evidence behind the use of optional filters is reviewed, the issue of anticoagulation is discussed and possible future filter developments are considered.

  10. Filter Fabrics for Airport Drainage.

    Science.gov (United States)

    1979-09-01

    pneumatically filling a woven polypropylene stocking with sand and vibrating it into a prebored hole, while another method uses a polyester nonwoven fabric...Selected Nonwoven Filter Fabrics," Letter Report, June 1977, U. S. Army Engineer Waterways Experiment Station, CE, Vicksburg, Miss. 18. BalL, J. E...woven and nonwoven plastic filter fabric. It has been developed based on limited field performance observations and the laboratory test evaluation of

  11. Active Optical Lattice Filters

    Directory of Open Access Journals (Sweden)

    Gary Evans

    2005-06-01

    Full Text Available Optical lattice filter structures including gains are introduced and analyzed. The photonic realization of the active, adaptive lattice filter is described. The algorithms which map between gains space and filter coefficients space are presented and studied. The sensitivities of filter parameters with respect to gains are derived and calculated. An example which is relevant to adaptive signal processing is also provided.

  12. Design and development of an improved low-cost ceramic water filter based on the existing Potpaz home water treatment device for use within rural households of the Vhembe region

    OpenAIRE

    2012-01-01

    M.Tech. This project aimed to develop the Potpaz ceramic water filter into an improved filter design optimally suited to South African rural conditions, to provide potable water rather than contaminated water to households. Communities that do not have access to in-house treated water often end up with a contaminated water supply, as the water to be consumed is usually sourced from communal water collection points and stored in containers. There is evidence that the water consumed at point...

  13. Filter replacement lifetime prediction

    Science.gov (United States)

    Hamann, Hendrik F.; Klein, Levente I.; Manzer, Dennis G.; Marianno, Fernando J.

    2017-10-25

    Methods and systems for predicting a filter lifetime include building a filter effectiveness history based on contaminant sensor information associated with a filter; determining a rate of filter consumption with a processor based on the filter effectiveness history; and determining a remaining filter lifetime based on the determined rate of filter consumption. Methods and systems for increasing filter economy include measuring contaminants in an internal and an external environment; determining a cost of a corrosion rate increase if unfiltered external air intake is increased for cooling; determining a cost of increased air pressure to filter external air; and if the cost of filtering external air exceeds the cost of the corrosion rate increase, increasing an intake of unfiltered external air.

  14. BIOMASS-FUELED, SMALL-SCALE, INTEGRATED-GASIFIER, GAS-TURBINE POWER PLANT: PROGRESS REPORT ON THE PHASE 2 DEVELOPMENT

    Science.gov (United States)

    The paper reports the latest efforts to complete development of Phase 2 of a three-phase effort to develop a family of small-scale (1 to 20 MWe) biomass-fueled power plants. The concept envisioned is an air-blown pressurized fluidized-bed gasifier followed by a dry hot gas clean...

  15. Real-valued composite filters for optical pattern recognition

    Science.gov (United States)

    Balendra, A.; Rajan, P. K.

    1993-01-01

    The design of real-valued composite filters for optical pattern recognition and classification is considered. A procedure to design a real-valued minimum average correlation energy (MACE) filter is developed. Also, the design of a real MVSDF-MACE filter that minimizes the output variance due to input noise while maintaining a sharp correlation peak is developed. Computer simulation indicates that the performance of these real filters is almost as good as that of the complex filters.

  16. Improved Notch Filter For Synchronous-Response Control

    Science.gov (United States)

    Johnson, Bruce G.; Downer, James R.; Eisenhaure, David B.; Hockney, Richard; Misovec, Kathleen

    1991-01-01

    Tracking differential-notch filter (TDNF) developed to retain good synchronous-response performance of notch filter, but with vastly improved stability properties. Measurement error perfectly filtered from feedback signal used to drive compensator. Provides good stability of simple lead/lag compensator combined with good synchronous-response performance gained by addition of notch filter.

  17. UV filters for lighting of plants

    Energy Technology Data Exchange (ETDEWEB)

    Doehring, T.; Koefferlein, M.; Thiel, S.; Seidlitz, H.K.; Payer, H.D. [GSF-Forschungszentrum fuer Umwelt und Gesundheit GmbH, Oberschleissheim (Germany)

    1994-12-31

    Different filter glasses are available which provide absorption properties suitable for gradual changes of the spectral UV-B illumination of artificial lighting. Using a distinct set of lamps and filter glasses an acceptable simulation of the UV-B part of natural global radiation can be achieved. The ageing of these and other filter materials under the extreme UV radiation in the lamphouse of a solar simulator is presently unavoidable. This instability can be dealt with only by a precise spectral monitoring and by replacing the filters accordingly. For this reason attempts would be useful to develop real ozone filters which can replace glass filters. In any case chamber experiments require a careful selection of the filter material used and must be accompanied by a continuous UV-B monitoring.

  18. Sensory Pollution from Bag Filters, Carbon Filters and Combinations

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Clausen, Geo; Weschler, Charles J.

    2008-01-01

    by an upstream pre-filter (changed monthly), an EU7 filter protected by an upstream activated carbon (AC) filter, and EU7 filters with an AC filter either downstream or both upstream and downstream. In addition, two types of stand-alone combination filters were evaluated: a bag-type fiberglass filter...

  19. Advances in Collaborative Filtering

    Science.gov (United States)

    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.

  20. Origin of warm and hot gas emission from low-mass protostars: Herschel-HIFI observations of CO J = 16-15. I. Line profiles, physical conditions, and H2O abundance

    Science.gov (United States)

    Kristensen, L. E.; van Dishoeck, E. F.; Mottram, J. C.; Karska, A.; Yıldız, U. A.; Bergin, E. A.; Bjerkeli, P.; Cabrit, S.; Doty, S.; Evans, N. J.; Gusdorf, A.; Harsono, D.; Herczeg, G. J.; Johnstone, D.; Jørgensen, J. K.; van Kempen, T. A.; Lee, J.-E.; Maret, S.; Tafalla, M.; Visser, R.; Wampfler, S. F.

    2017-09-01

    component. The former originates in either outflow cavity shocks or the disk wind, and the latter in irradiated shocks. The low water abundance can be explained by photodissociation. The ubiquity of the warm and hot CO components suggest that fundamental mechanisms govern the excitation of these components; we hypothesize that the warm component arises when H2 stops being the dominant coolant. In this scenario, the hot component arises in cooling molecular H2-poor gas just prior to the onset of H2 formation. High spectral resolution observations of highly excited CO transitions uniquely shed light on the origin of warm and hot gas in low-mass protostellar objects. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  1. In Defense of Filtering.

    Science.gov (United States)

    Burt, David

    1997-01-01

    Presents responses to 10 common arguments against the use of Internet filters in libraries. Highlights include keyword blocking; selection of materials; liability of libraries using filters; users' judgments; Constitutional issues, including First Amendment rights; and censorship. (LRW)

  2. HEPA filter monitoring program

    Science.gov (United States)

    Kirchner, K. N.; Johnson, C. M.; Aiken, W. F.; Lucerna, J. J.; Barnett, R. L.; Jensen, R. T.

    1986-07-01

    The testing and replacement of HEPA filters, widely used in the nuclear industry to purify process air, are costly and labor-intensive. Current methods of testing filter performance, such as differential pressure measurement and scanning air monitoring, allow determination of overall filter performance but preclude detection of incipient filter failure such as small holes in the filters. Using current technology, a continual in-situ monitoring system was designed which provides three major improvements over current methods of filter testing and replacement. The improvements include: cost savings by reducing the number of intact filters which are currently being replaced unnecessarily; more accurate and quantitative measurement of filter performance; and reduced personnel exposure to a radioactive environment by automatically performing most testing operations.

  3. Bites of Lists - mapping and filtering sublists

    DEFF Research Database (Denmark)

    Nørmark, Kurt

    The idea of applying map and filter functions on consecutive sublists instead of on individual list elements is discussed and developed in this paper. A non-empty, consecutive sublist is called a bite. Both map and filter functions accept a function parameter - a bite function - which...... is responsible for returning a prefix bite of a list. We develop families of bite functions via a collection of higher-order bite generators. On top of the bite generators, a number of bite mapping and bite filtering functions are introduced. We illustrate the usefulness of bite mapping and filtering via...

  4. MST Filterability Tests

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, M. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Burket, P. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Duignan, M. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    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.

  5. Oriented Fiber Filter Media

    OpenAIRE

    R. Bharadwaj; A. Patel, S. Chokdeepanich, Ph.D.; G.G. Chase, Ph.D.

    2008-01-01

    Coalescing filters are widely used throughout industry and improved performance will reduce droplet emissions and operating costs. Experimental observations show orientation of micro fibers in filter media effect the permeability and the separation efficiency of the filter media. In this work two methods are used to align the fibers to alter the filter structure. The results show that axially aligned fiber media improve quality factor on the order of 20% and cutting media on an angle from a t...

  6. Filter service system

    Science.gov (United States)

    Sellers, Cheryl L [Peoria, IL; Nordyke, Daniel S [Arlington Heights, IL; Crandell, Richard A [Morton, IL; Tomlins, Gregory [Peoria, IL; Fei, Dong [Peoria, IL; Panov, Alexander [Dunlap, IL; Lane, William H [Chillicothe, IL; Habeger, Craig F [Chillicothe, IL

    2008-12-09

    According to an exemplary embodiment of the present disclosure, a system for removing matter from a filtering device includes a gas pressurization assembly. An element of the assembly is removably attachable to a first orifice of the filtering device. The system also includes a vacuum source fluidly connected to a second orifice of the filtering device.

  7. Bias aware Kalman filters

    DEFF Research Database (Denmark)

    Drecourt, J.-P.; Madsen, H.; Rosbjerg, Dan

    2006-01-01

    This paper reviews two different approaches that have been proposed to tackle the problems of model bias with the Kalman filter: the use of a colored noise model and the implementation of a separate bias filter. Both filters are implemented with and without feedback of the bias into the model sta...

  8. HEPA filter encapsulation

    Science.gov (United States)

    Gates-Anderson, Dianne D.; Kidd, Scott D.; Bowers, John S.; Attebery, Ronald W.

    2003-01-01

    A low viscosity resin is delivered into a spent HEPA filter or other waste. The resin is introduced into the filter or other waste using a vacuum to assist in the mass transfer of the resin through the filter media or other waste.

  9. Adjustable Fiber Optic Microwave Transversal Filters

    Science.gov (United States)

    Shadaram, Mehdi; Lutes, George F.; Logan, Ronald T.; Maleki, Lutfollah

    1994-01-01

    Microwave transversal filters implemented as adjustable tapped fiber optic delay lines developed. Main advantages of these filters (in comparison with conventional microwave transversal filters) are small size, light weight, no need for matching of radio-frequency impedances, no need for shielding against electromagnetic radiation at suboptical frequencies, no need for mechanical tuning, high stability of amplitude and phase, and active control of transfer functions. Weights of taps in fiber optic delay lines adjusted.

  10. Spectral filtering for plant production

    Energy Technology Data Exchange (ETDEWEB)

    Young, R.E.; McMahon, M.J.; Rajapakse, N.C.; Becoteau, D.R.

    1994-12-31

    Research to date suggests that spectral filtering can be an effective alternative to chemical growth regulators for altering plant development. If properly implemented, it can be nonchemical and environmentally friendly. The aqueous CuSO{sub 4}, and CuCl{sub 2} solutions in channelled plastic panels have been shown to be effective filters, but they can be highly toxic if the solutions contact plants. Some studies suggest that spectral filtration limited to short EOD intervals can also alter plant development. Future research should be directed toward confirmation of the influence of spectral filters and exposure times on a broader range of plant species and cultivars. Efforts should also be made to identify non-noxious alternatives to aqueous copper solutions and/or to incorporate these chemicals permanently into plastic films and panels that can be used in greenhouse construction. It would also be informative to study the impacts of spectral filters on insect and microbal populations in plant growth facilities. The economic impacts of spectral filtering techniques should be assessed for each delivery methodology.

  11. Filtering multifocal VEP signals using Prony's method.

    Science.gov (United States)

    Fernández, A; de Santiago, L; Blanco, R; Pérez-Rico, C; Rodríguez-Ascariz, J M; Barea, R; Miguel-Jiménez, J M; García-Luque, J R; Ortiz del Castillo, M; Sánchez-Morla, E M; Boquete, L

    2015-01-01

    This paper describes use of Prony's method as a filter applied to multifocal visual-evoked-potential (mfVEP) signals. Prony's method can be viewed as an extension of Fourier analysis that allows a signal to be decomposed into a linear combination of functions with different amplitudes, damping factors, frequencies and phase angles. By selecting Prony method parameters, a frequency filter has been developed which improves signal-to-noise ratio (SNR). Three different criteria were applied to data recorded from control subjects to produce three separate datasets: unfiltered raw data, data filtered using the traditional method (fast Fourier transform: FFT), and data filtered using Prony's method. Filtering using Prony's method improved the signals' original SNR by 44.52%, while the FFT filter improved the SNR by 33.56%. The extent to which signal can be separated from noise was analysed using receiver-operating-characteristic (ROC) curves. The area under the curve (AUC) was greater in the signals filtered using Prony's method than in the original signals or in those filtered using the FFT. filtering using Prony's method improves the quality of mfVEP signal pre-processing when compared with the original signals, or with those filtered using the FFT. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. The discrete prolate spheroidal filter as a digital signal processing tool

    Science.gov (United States)

    Mathews, J. D.; Breakall, J. K.; Karawas, G. K.

    1983-01-01

    The discrete prolate spheriodall (DPS) filter is one of the glass of nonrecursive finite impulse response (FIR) filters. The DPS filter is superior to other filters in this class in that it has maximum energy concentration in the frequency passband and minimum ringing in the time domain. A mathematical development of the DPS filter properties is given, along with information required to construct the filter. The properties of this filter were compared with those of the more commonly used filters of the same class. Use of the DPS filter allows for particularly meaningful statements of data time/frequency resolution cell values. The filter forms an especially useful tool for digital signal processing.

  13. Filtering and control of wireless networked systems

    CERN Document Server

    Zhang, Dan; Yu, Li

    2017-01-01

    This self-contained book, written by leading experts, offers a cutting-edge, in-depth overview of the filtering and control of wireless networked systems. It addresses the energy constraint and filter/controller gain variation problems, and presents both the centralized and the distributed solutions. The first two chapters provide an introduction to networked control systems and basic information on system analysis. Chapters (3–6) then discuss the centralized filtering of wireless networked systems, presenting different approaches to deal with energy efficiency and filter/controller gain variation problems. The next part (chapters 7–10) explores the distributed filtering of wireless networked systems, addressing the main problems of energy constraint and filter gain variation. The final part (chapters 11–14) focuses on the distributed control of wireless networked systems. development of wireless networked systems for communication and control applications, the bo...

  14. G-Filtering Nonstationary Time Series

    Directory of Open Access Journals (Sweden)

    Mengyuan Xu

    2012-01-01

    Full Text Available The classical linear filter can successfully filter the components from a time series for which the frequency content does not change with time, and those nonstationary time series with time-varying frequency (TVF components that do not overlap. However, for many types of nonstationary time series, the TVF components often overlap in time. In such a situation, the classical linear filtering method fails to extract components from the original process. In this paper, we introduce and theoretically develop the G-filter based on a time-deformation technique. Simulation examples and a real bat echolocation example illustrate that the G-filter can successfully filter a G-stationary process whose TVF components overlap with time.

  15. Programmable Baseband Filter for Multistandard Mobile Phones

    DEFF Research Database (Denmark)

    Jensen, Rasmus Glarborg; Christensen, Kåre Tais; Bruun, Erik

    2003-01-01

    of the input transconductor. The entire filter consumes between 2.5 mW and 7.5 mW, depending on the desired noise performance. It is implemented in a standard 0.25 mum CMOS process. A test circuit has been developed and fabricated and measurements show that both the required programmability and the required......This paper describes a channel selection filter for mobile communication systems using a direct down conversion architecture. The filter can be programmed to meet the requirements of different communication standards, including GSM (Global System for Mobile communication), WCDMA (Wideband Code...... Division Multiple Access), and Bluetooth. The filter includes a novel DC offset compensation circuit that combines offset sampling in GSM mode with high pass filtering in WCDMA mode. The filter can be programmed to different noise performance levels by programming the impedance level and power consumption...

  16. The intractable cigarette ‘filter problem’

    Science.gov (United States)

    2011-01-01

    Background When lung cancer fears emerged in the 1950s, cigarette companies initiated a shift in cigarette design from unfiltered to filtered cigarettes. Both the ineffectiveness of cigarette filters and the tobacco industry's misleading marketing of the benefits of filtered cigarettes have been well documented. However, during the 1950s and 1960s, American cigarette companies spent millions of dollars to solve what the industry identified as the ‘filter problem’. These extensive filter research and development efforts suggest a phase of genuine optimism among cigarette designers that cigarette filters could be engineered to mitigate the health hazards of smoking. Objective This paper explores the early history of cigarette filter research and development in order to elucidate why and when seemingly sincere filter engineering efforts devolved into manipulations in cigarette design to sustain cigarette marketing and mitigate consumers' concerns about the health consequences of smoking. Methods Relevant word and phrase searches were conducted in the Legacy Tobacco Documents Library online database, Google Patents, and media and medical databases including ProQuest, JSTOR, Medline and PubMed. Results 13 tobacco industry documents were identified that track prominent developments involved in what the industry referred to as the ‘filter problem’. These reveal a period of intense focus on the ‘filter problem’ that persisted from the mid-1950s to the mid-1960s, featuring collaborations between cigarette producers and large American chemical and textile companies to develop effective filters. In addition, the documents reveal how cigarette filter researchers' growing scientific knowledge of smoke chemistry led to increasing recognition that filters were unlikely to offer significant health protection. One of the primary concerns of cigarette producers was to design cigarette filters that could be economically incorporated into the massive scale of cigarette

  17. Microwave filters and circuits contributions from Japan

    CERN Document Server

    Matsumoto, Akio

    1970-01-01

    Microwave Filters and Circuits: Contributions from Japan covers ideas and novel circuits used to design microwave filter that have been developed in Japan, as well as network theory into the field of microwave transmission networks. The book discusses the general properties and synthesis of transmission-line networks; transmission-line filters on the image-parameter basis; and experimental results on a class of transmission-line filter constructed only with commensurate TEM lossless transmission lines. The text describes lines constants, approximation problems in transmission-line networks, as

  18. Development of intelligent surveillance system (ISS) in region of interest (ROI) using Kalman filter and camshift on Raspberry Pi 2

    Science.gov (United States)

    Park, Junghun; Hong, Kicheon

    2017-06-01

    Due to the improvement of the picture quality of closed-circuit television (CCTV), the demand for CCTV has increased rapidly and its market size has also increased. The current system structure of CCTV transfers compressed images without analysis received from CCTV to a control center. The compressed images are suitable for the evidence required for a criminal arrest, but they cannot prevent crime in real time, which has been considered a limitation. Thus, the present paper proposes a system implementation that can prevent crimes by applying a situation awareness system at the back end of the CCTV cameras for image acquisition to prevent crimes efficiently. In the system implemented in the present paper, the region of interest (ROI) is set virtually within the image data when a barrier, such as fence, cannot be installed in actual sites and unauthorized intruders are tracked constantly through data analysis and recognized in the ROI via the developed algorithm. Additionally, a searchlight or alarm sound is activated to prevent crime in real time and the urgent information is transferred to the control center. The system was implemented in the Raspberry Pi 2 board to be run in real time. The experiment results showed that the recognition success rate was 85% or higher and the track accuracy was 90% or higher. By utilizing the system, crime prevention can be achieved by implementing a social safety network.

  19. Compact planar microwave blocking filters

    Science.gov (United States)

    U-Yen, Kongpop (Inventor); Wollack, Edward J. (Inventor)

    2012-01-01

    A compact planar microwave blocking filter includes a dielectric substrate and a plurality of filter unit elements disposed on the substrate. The filter unit elements are interconnected in a symmetrical series cascade with filter unit elements being organized in the series based on physical size. In the filter, a first filter unit element of the plurality of filter unit elements includes a low impedance open-ended line configured to reduce the shunt capacitance of the filter.

  20. A biological oil adsorption filter

    Energy Technology Data Exchange (ETDEWEB)

    Pasila, A. [University of Helsinki (Finland). Dept. of Agricultural Engineering and Household Technology

    2005-12-01

    A new oil adsorption method called adsorption filtration (AF) has been developed. It is a technology where by oil residues can be cleaned from water by running it through a simple filter made from freeze treated, dried, milled and then fragmented plant material. By choosing suitable plants and fragmentation sizes it is possible to produce filters, which pass water but adsorb oil. The aim of this study was to investigate the possibilities of manufacturing oil adsorbing filter materials from reed canary grass (Phalaris arundinacea), flax (Linum usitatissimum L.) or hemp fibre (Cannabis sativa L.). The oil (80 ml) was mixed with de-ionised water (200 ml) and this mixture was filtered through 10 or 20 g adsorption filters. Fine spring harvested hemp fibre (diameter less than 1 mm) and reed canary grass fragments adsorb 2-4 g of oil per gram of adsorption material compared to 1-3 g of water. Adsorption filtration is thus a novel way of gathering spilled oil in shallow coastal waters before the oil reaches the shore. (author)

  1. Performance of efficient digital filters

    OpenAIRE

    Agbonogieva, Osazee

    2009-01-01

    An efficient digital signal uses an 8-bit embedded processor on a DSP platform, which was developed to design the technical specifications in this final year project. The goal was to design a program that counts maximum bits time of 8, 16, 32 and 64 on a Matlab platform, specify the filter design and generate the C header as an export bit integer signed or unsigned, copy the filter coefficients to a platform called PSoC, and initialize with the coefficients generated by Matlab. The prop...

  2. The diffuse ensemble filter

    Directory of Open Access Journals (Sweden)

    X. Yang

    2009-07-01

    Full Text Available A new class of ensemble filters, called the Diffuse Ensemble Filter (DEnF, is proposed in this paper. The DEnF assumes that the forecast errors orthogonal to the first guess ensemble are uncorrelated with the latter ensemble and have infinite variance. The assumption of infinite variance corresponds to the limit of "complete lack of knowledge" and differs dramatically from the implicit assumption made in most other ensemble filters, which is that the forecast errors orthogonal to the first guess ensemble have vanishing errors. The DEnF is independent of the detailed covariances assumed in the space orthogonal to the ensemble space, and reduces to conventional ensemble square root filters when the number of ensembles exceeds the model dimension. The DEnF is well defined only in data rich regimes and involves the inversion of relatively large matrices, although this barrier might be circumvented by variational methods. Two algorithms for solving the DEnF, namely the Diffuse Ensemble Kalman Filter (DEnKF and the Diffuse Ensemble Transform Kalman Filter (DETKF, are proposed and found to give comparable results. These filters generally converge to the traditional EnKF and ETKF, respectively, when the ensemble size exceeds the model dimension. Numerical experiments demonstrate that the DEnF eliminates filter collapse, which occurs in ensemble Kalman filters for small ensemble sizes. Also, the use of the DEnF to initialize a conventional square root filter dramatically accelerates the spin-up time for convergence. However, in a perfect model scenario, the DEnF produces larger errors than ensemble square root filters that have covariance localization and inflation. For imperfect forecast models, the DEnF produces smaller errors than the ensemble square root filter with inflation. These experiments suggest that the DEnF has some advantages relative to the ensemble square root filters in the regime of small ensemble size, imperfect model, and copious

  3. Compact microstrip bandpass filter with tunable notch

    DEFF Research Database (Denmark)

    Christensen, Silas; Zhurbenko, Vitaliy; Johansen, Tom Keinicke

    2014-01-01

    Two different designs combining a bandpass and a notch filter are developed to operate in the receiving band from 350–470 MHz. The bandpass filter is designed from a simple structure, by use of only four short circuited stubs and a half wavelength transmission line connecting the stubs. The tunable...

  4. Performance Assessment of Sintered Metal Fiber Filters in Fluid Catalytic Cracking Unit

    Directory of Open Access Journals (Sweden)

    Liang Yang

    2014-01-01

    Full Text Available A long-term test was performed in a fluid catalytic cracking (FCC hot gas filtration facility using sintered metal candle filters. The operating temperature and pressure were maximum 55°C and 0.28 MPa, respectively. Specific particle sampling systems were used to measure the particle size and concentration directly at high temperature. The range of inlet particle concentration is from 150 to 165 mg/Nm3. The outlet particle concentration is in the range of 0.71–2.77 mg/Nm3 in stable operation. The filtration efficiency is from 98.23% to 99.55%. The inlet volume median diameter and the outlet volume median diameter of the particle are about 1 μm and 2.2 μm, respectively. The cake thickness is calculated based on the equation of Carman-Kozeny. The effects of operating parameters including face velocity, gas cleaning pressure, pulse duration, and maximum pressure drop were investigated. The optimal operating conditions and cleaning strategies were determined. The results show that sintered metal fiber filters are suitable for industrial application due to the good performance and high efficiency observed.

  5. Very Large Solar Rejection Filter for Laser Communication Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Surface Optics Corporation (SOC) will develop a band pass filter comprised of a visible dielectric mirror and an induced transmission filter, applied to two sides of...

  6. Spot- Zombie Filtering System

    OpenAIRE

    Arathy Rajagopal; B. Geethanjali; Arulprakash P

    2015-01-01

    A major security challenge on the Internet is the existence of the large number of compromised machines. Such machines have been increasingly used to launch various security attacks including spamming and spreading malware, DDoS, and identity theft. These compromised machines are called "Zombies". In general E-mail applications and providers uses spam filters to filter the spam messages. Spam filtering is a technique for discriminating the genuine message from the spam messages. The attackers...

  7. Fundamentals of Stochastic Filtering

    CERN Document Server

    Crisan, Dan

    2008-01-01

    The objective of stochastic filtering is to determine the best estimate for the state of a stochastic dynamical system from partial observations. The solution of this problem in the linear case is the well known Kalman-Bucy filter which has found widespread practical application. The purpose of this book is to provide a rigorous mathematical treatment of the non-linear stochastic filtering problem using modern methods. Particular emphasis is placed on the theoretical analysis of numerical methods for the solution of the filtering problem via particle methods. The book should provide sufficient

  8. Stripe delay filters

    OpenAIRE

    Zakharov, Alexander V.; Ilchenko, Mykhailo Ye.; Trubarov, Igor V.; Pinchuk, Ludmila S.

    2016-01-01

    There are considered constructions of microsized stripe delay filters, which are realized on a basis of ceramic materials with high dielectric permittivity. Delay time of non-minimal phase filters is 7–12 ns at frequencies of 1900 MHz with relative bandwidth of 3.6–3.85%. Filters dimensions are comparable with ones used in portable communication devices. Dimensions of researched three-resonator filter at frequency of 1900 MHz are 8.4×5×2 mm with material dielectric permittivity εr = 92, and 5...

  9. Particle filters for random set models

    CERN Document Server

    Ristic, Branko

    2013-01-01

    “Particle Filters for Random Set Models” presents coverage of state estimation of stochastic dynamic systems from noisy measurements, specifically sequential Bayesian estimation and nonlinear or stochastic filtering. The class of solutions presented in this book is based  on the Monte Carlo statistical method. The resulting  algorithms, known as particle filters, in the last decade have become one of the essential tools for stochastic filtering, with applications ranging from  navigation and autonomous vehicles to bio-informatics and finance. While particle filters have been around for more than a decade, the recent theoretical developments of sequential Bayesian estimation in the framework of random set theory have provided new opportunities which are not widely known and are covered in this book. These recent developments have dramatically widened the scope of applications, from single to multiple appearing/disappearing objects, from precise to imprecise measurements and measurement models. This book...

  10. Development of an extended Kalman filter for the self-sensing application of a spring-biased shape memory alloy wire actuator

    Science.gov (United States)

    Gurung, H.; Banerjee, A.

    2016-02-01

    This report presents the development of an extended Kalman filter (EKF) to harness the self-sensing capability of a shape memory alloy (SMA) wire, actuating a linear spring. The stress and temperature of the SMA wire, constituting the state of the system, are estimated using the EKF, from the measured change in electrical resistance (ER) of the SMA. The estimated stress is used to compute the change in length of the spring, eliminating the need for a displacement sensor. The system model used in the EKF comprises the heat balance equation and the constitutive relation of the SMA wire coupled with the force-displacement behavior of a spring. Both explicit and implicit approaches are adopted to evaluate the system model at each time-update step of the EKF. Next, in the measurement-update step, estimated states are updated based on the measured electrical resistance. It has been observed that for the same time step, the implicit approach consumes less computational time than the explicit method. To verify the implementation, EKF estimated states of the system are compared with those of an established model for different inputs to the SMA wire. An experimental setup is developed to measure the actual spring displacement and ER of the SMA, for any time-varying voltage applied to it. The process noise covariance is decided using a heuristic approach, whereas the measurement noise covariance is obtained experimentally. Finally, the EKF is used to estimate the spring displacement for a given input and the corresponding experimentally obtained ER of the SMA. The qualitative agreement between the EKF estimated displacement with that obtained experimentally reveals the true potential of this approach to harness the self-sensing capability of the SMA.

  11. Wideband Lithium Niobate FBAR Filters

    Directory of Open Access Journals (Sweden)

    Thomas Baron

    2013-01-01

    Full Text Available Filters based on film bulk acoustic resonators (FBARs are widely used for mobile phone applications, but they can also address wideband aerospace requirements. These devices need high electromechanical coupling coefficients to achieve large band pass filters. The piezoelectric material LiNbO3 complies with such specifications and is compatible with standard fabrication processes. In this work, simple metal—LiNbO3—metal structures have been developed to fabricate single FBAR elements directly connected to each other on a single chip. A fabrication process based on LiNbO3/silicon Au-Au bonding and LiNbO3 lapping/polishing has been developed and is proposed in this paper. Electrical measurements of these FBAR filters are proposed and commented exhibiting filters with 8% of fractional bandwidth and 3.3 dB of insertion losses. Electrical measurements show possibilities to obtain 14% of fractional bandwidth. These devices have been packaged, allowing for power handling, thermal, and ferroelectric tests, corresponding to spatial conditions.

  12. Randomized Filtering Algorithms

    DEFF Research Database (Denmark)

    Katriel, Irit; Van Hentenryck, Pascal

    2008-01-01

    of AllDifferent and is generalization, the Global Cardinality Constraint. The first delayed filtering scheme is a Monte Carlo algorithm: its running time is superior, in the worst case, to that of enforcing are consistency after every domain event, while its filtering effectiveness is analyzed...

  13. Multilevel ensemble Kalman filter

    KAUST Repository

    Chernov, Alexey

    2016-01-06

    This work embeds a multilevel Monte Carlo (MLMC) sampling strategy into the Monte Carlo step of the ensemble Kalman filter (EnKF). In terms of computational cost vs. approximation error the asymptotic performance of the multilevel ensemble Kalman filter (MLEnKF) is superior to the EnKF s.

  14. Updating the OMERACT filter

    DEFF Research Database (Denmark)

    Wells, George; Beaton, Dorcas E; Tugwell, Peter

    2014-01-01

    The "Discrimination" part of the OMERACT Filter asks whether a measure discriminates between situations that are of interest. "Feasibility" in the OMERACT Filter encompasses the practical considerations of using an instrument, including its ease of use, time to complete, monetary costs, and inter...

  15. Fast Anisotropic Gauss Filtering

    NARCIS (Netherlands)

    Geusebroek, J.M.; Smeulders, A.W.M.; van de Weijer, J.; Heyden, A.; Sparr, G.; Nielsen, M.; Johansen, P.

    2002-01-01

    We derive the decomposition of the anisotropic Gaussian in a one dimensional Gauss filter in the x-direction followed by a one dimensional filter in a non-orthogonal direction phi. So also the anisotropic Gaussian can be decomposed by dimension. This appears to be extremely efficient from a

  16. Vena cava filter; Vena-cava-Filter

    Energy Technology Data Exchange (ETDEWEB)

    Helmberger, T. [Klinikum Bogenhausen, Institut fuer Diagnostische und Interventionelle Radiologie und Nuklearmedizin, Muenchen (Germany)

    2007-05-15

    Fulminant pulmonary embolism is one of the major causes of death in the Western World. In most cases, deep leg and pelvic venous thrombosis are the cause. If an anticoagulant/thrombotic therapy is no longer possible or ineffective, a vena cava filter implant may be indicated if an embolism is threatening. Implantation of the filter is a simple and safe intervention. Nevertheless, it is necessary to take into consideration that the data base for determining the indications for this treatment are very limited. Currently, a reduction in the risk of thromboembolism with the use of filters of about 30%, of recurrences of almost 5% and fatal pulmonary embolism of 1% has been reported, with a risk of up to 20% of filter induced vena cava thrombosis. (orig.) [German] Die fulminante Lungenembolie zaehlt zu den Haupttodesursachen in der westlichen Welt. In der Mehrzahl der Faelle sind tiefe Bein- und Beckenvenenthrombosen ursaechlich verantwortlich. Ist eine antikoagulative/-thrombotische Therapie nicht (mehr) moeglich oder unwirksam, kann bei drohender Emboliegefahr die Vena-cava-Filterimplantation indiziert sein. Die Filterimplantation ist eine einfache und sehr sichere Intervention. Dennoch muss bei der Indikationsstellung beruecksichtigt werden, dass die Datenlage zur Wirksamkeit sehr limitiert ist. So wird aktuell ueber eine Reduktion des Thrombembolierisikos um 30% bei Embolierezidiven von knapp 5% und fatalen Lungenembolien von 1% unter Filterprophylaxe berichtet, bei einem Risiko von bis zu 20% fuer die filterinduzierte Vena-cava-Thrombose. (orig.)

  17. Learning Separable Filters.

    Science.gov (United States)

    Sironi, Amos; Tekin, Bugra; Rigamonti, Roberto; Lepetit, Vincent; Fua, Pascal

    2015-01-01

    Learning filters to produce sparse image representations in terms of over-complete dictionaries has emerged as a powerful way to create image features for many different purposes. Unfortunately, these filters are usually both numerous and non-separable, making their use computationally expensive. In this paper, we show that such filters can be computed as linear combinations of a smaller number of separable ones, thus greatly reducing the computational complexity at no cost in terms of performance. This makes filter learning approaches practical even for large images or 3D volumes, and we show that we significantly outperform state-of-the-art methods on the curvilinear structure extraction task, in terms of both accuracy and speed. Moreover, our approach is general and can be used on generic convolutional filter banks to reduce the complexity of the feature extraction step.

  18. Development of a practicable measuring method for continuous determination of the concentration and particle size distribution of dusts in air filter elements. Part project: Development of the scientific groundwork. Final report; Entwicklung eines feldtauglichen Messverfahrens zur kontinuierlichen Bestimmung der Konzentration und Groessenverteilung von Staeuben an Luftfiltereinsaetzen. Teilprojekt: Erarbeitung der wissenschaftlichen Grundlagen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Weichert, R.; Rulik, O.

    1997-06-01

    Filters may be used for reducing emissions of particulate pollutants from processing plants or for air cleaning in ventilation plants. The efficiency of a filter depends on its material, design, and operating conditions, notably the concentration and size of partciles, and on its load, i.e., its working hours. The purpose of the present project was to develop an inexpensive, easy-to-use, practicable measuring method for on-line measurement of the concentration and particle size distribution of dusts upstream (raw gas) and downstream (clean gas) of filters installed in processing plants, thus providing a means of continuously monitoring filter efficiency. The measuring principle of the developed method is based on the light scatter produced by individual particles passing through the measuring zone. The particle size measuring range is from 0.3 to 30 {mu}m, thus providing for the majority of all respirable dusts. The concentration measuring range is from a few mg/m{sup 3} on the clean gas side up to several g/m{sup 3} on the raw gas side. Special measures were needed to accomodate such a wide concentration range in a single measuring device. One of tasks of the study was to develop the technology required for this. (orig./SR) [Deutsch] Zur Minderung von Emissionen partikelfoermiger Schadstoffe aus verfahrenstechnischen Anlagen sowie zur Reinhaltung der Luft in Lueftungsanlagen werden Filter eingesetzt. Die Wirksamkeit dieser Filter haengt ab - von Material und Aufbau des Filters, von den Betriebsbedingungen des Filters, insbesondere von der Konzentration und der Groesse der Partikel und - von der Beladung des Filters, d.h. von seiner Betriebsdauer. Ziel des Vorhabens ist es, ein kostenguenstiges, handliches und feldtaugliches Messgeraet zu entwickeln, mit dem in technischen Anlagen die Konzentration und Groessenverteilung von Staeuben sowohl vor dem Filter (Rohgas) als auch hinter dem Filter (Reingas) on-line gemessen und so die Wirksamkeit des Filters

  19. Kalman filtering theory and practice with MATLAB

    CERN Document Server

    Grewal, M

    2015-01-01

    The definitive textbook and professional reference on Kalman Filtering fully updated, revised, and expanded This book contains the latest developments in the implementation and application of Kalman filtering. Authors Grewal and Andrews draw upon their decades of experience to offer an in-depth examination of the subtleties, common pitfalls, and limitations of estimation theory as it applies to real-world situations. They present many illustrative examples including adaptations for nonlinear filtering, global navigation satellite systems, the error modeling of gyros and accelerometers, inertial navigation systems, and freeway traffic control. Kalman Filtering: Theory and Practice Using MATLAB, Fourth Edition is an ideal textbook in advanced undergraduate and beginning graduate courses in stochastic processes and Kalman filtering. It is also appropriate for self-instruction or review by practicing engineers and scientists who want to learn more about this important topic.

  20. Designer Infrared Filters using Stacked Metal Lattices

    Science.gov (United States)

    Smith, Howard A.; Rebbert, M.; Sternberg, O.

    2003-01-01

    We have designed and fabricated infrared filters for use at wavelengths greater than or equal to 15 microns. Unlike conventional dielectric filters used at the short wavelengths, ours are made from stacked metal grids, spaced at a very small fraction of the performance wavelengths. The individual lattice layers are gold, the spacers are polyimide, and they are assembled using integrated circuit processing techniques; they resemble some metallic photonic band-gap structures. We simulate the filter performance accurately, including the coupling of the propagating, near-field electromagnetic modes, using computer aided design codes. We find no anomalous absorption. The geometrical parameters of the grids are easily altered in practice, allowing for the production of tuned filters with predictable useful transmission characteristics. Although developed for astronomical instrumentation, the filters arc broadly applicable in systems across infrared and terahertz bands.

  1. Field of Particle Filters Image Inpainting

    DEFF Research Database (Denmark)

    Cuzol, Anne; Pedersen, Kim Steenstrup; Nielsen, Mads

    2008-01-01

    We present a novel algorithm for solving the image inpainting problem based on a field of locally interacting particle filters. Image inpainting, also known as image completion, is concerned with the problem of filling image regions with new visually plausible data. In order to avoid the difficulty...... of solving the problem globally for the region to be inpainted, we introduce a field of local particle filters. The states of the particle filters are image patches. Global consistency is enforced by a Markov random field image model which connects neighbouring particle filters. The benefit of using locally...... interacting particle filters is that several competing hypotheses on inpainting solutions are kept active, allowing the method to provide globally consistent solutions on problems where other local methods may fail. We provide examples of applications of the developed method. Keywords: Inpainting · Image...

  2. Performance and optimisation of trickling filters on eel farms

    NARCIS (Netherlands)

    Kamstra, A.; Heul, van der J.W.; Nijhof, M.

    1998-01-01

    The design of trickling filters used on commercial eel farms differs considerably with respect to dimensions, hydraulic and substrate loads and filter medium applied. In this paper, a model, developed for ammonium removal in a pilot-scale trickling filter, has been validated for a range of

  3. A design aid for determining width of filter strips

    Science.gov (United States)

    M.G. Dosskey; M.J. Helmers; D.E. Eisenhauer

    2008-01-01

    watershed planners need a tool for determining width of filter strips that is accurate enough for developing cost-effective site designs and easy enough to use for making quick determinations on a large number and variety of sites.This study employed the process-based Vegetative Filter Strip Model to evaluate the relationship between filter strip width and trapping...

  4. Metal Mesh Filters for Terahertz Receivers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The technical objective of this SBIR program is to develop and demonstrate metal mesh filters for use in NASA's low noise receivers for terahertz astronomy and...

  5. High Performance Miniature Bandpass Filters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is submitted for developing low impedance, miniature bandpass RF frequency filter via MEMS technique, in applications of SMAP, Aquarius follow-on,...

  6. Investigation of Locally Made Ceramic Filter for Household Water Treatment

    OpenAIRE

    Nurmiyanto, Awaluddin; Prasetya, Agus

    2012-01-01

    This research have objective to develop and evaluate the performance of ceramic filter in using locally available material at Yogyakarta. Ceramic filter are made by pressing a mixture of clay, discarded pottery (grog) and combustible material (coconut fiber) into the molder. Curving processes are then applied to form tubular shape before firing it using kiln (1005°C). Filtration test were performed gravitationally by flowing well water into ceramic filter. Filtered water quality was complying...

  7. Ceramic fiber reinforced filter

    Science.gov (United States)

    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.

  8. Far infrared interference filters.

    Science.gov (United States)

    Varma, S P; Möller, K D

    1969-08-01

    Capacitive meshes for far ir, low pass filters are prepared from Cu layers on 2.5 micro plastic film. The properties of these meshes of different mesh constants g with their different combinations in two-mesh, fourmesh, and eight-mesh filters are studied in the spectral region 160 cm(-1) to 10 cm(-1) by the use of a grating spectrometer. The applications of these meshes as low pass filters in the far ir spectral region in a grating spectrometer are described.

  9. Circuits and filters handbook

    CERN Document Server

    Chen, Wai-Kai

    2003-01-01

    A bestseller in its first edition, The Circuits and Filters Handbook has been thoroughly updated to provide the most current, most comprehensive information available in both the classical and emerging fields of circuits and filters, both analog and digital. This edition contains 29 new chapters, with significant additions in the areas of computer-aided design, circuit simulation, VLSI circuits, design automation, and active and digital filters. It will undoubtedly take its place as the engineer's first choice in looking for solutions to problems encountered in the design, analysis, and behavi

  10. EMI filter design

    CERN Document Server

    Ozenbaugh, Richard Lee

    2011-01-01

    With today's electrical and electronics systems requiring increased levels of performance and reliability, the design of robust EMI filters plays a critical role in EMC compliance. Using a mix of practical methods and theoretical analysis, EMI Filter Design, Third Edition presents both a hands-on and academic approach to the design of EMI filters and the selection of components values. The design approaches covered include matrix methods using table data and the use of Fourier analysis, Laplace transforms, and transfer function realization of LC structures. This edition has been fully revised

  11. Radar data smoothing filter study

    Science.gov (United States)

    White, J. V.

    1984-01-01

    The accuracy of the current Wallops Flight Facility (WFF) data smoothing techniques for a variety of radars and payloads is examined. Alternative data reduction techniques are given and recommendations are made for improving radar data processing at WFF. A data adaptive algorithm, based on Kalman filtering and smoothing techniques, is also developed for estimating payload trajectories above the atmosphere from noisy time varying radar data. This algorithm is tested and verified using radar tracking data from WFF.

  12. Percutaneous caval filters for the prevention of pulmonary embolism

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, R.W.; Vorwerk, D.

    1988-07-01

    The Kimray-Greenfield filter is the most commonly used of all filters. Percutaneous insertion technique has made this filter more attractive also for interventional radiology. Its drawbacks are, in particular, the large calibre of the insertion instruments and its low effectivity in case of eccentric placing. Good results have been obtained to date with the specially developed cava filters that can be introduced percutaneously. Clinical and experimental studies have shown that some filters are particularly effective, such as the 'basket filter'; at the same time, these have also a higher thrombogenicity. However, independent of the choice of the cava filter, it seems that the operatively inserted filters are increasingly a thing of the past.

  13. Comparison of cryogenic low-pass filters

    Science.gov (United States)

    Thalmann, M.; Pernau, H.-F.; Strunk, C.; Scheer, E.; Pietsch, T.

    2017-11-01

    Low-temperature electronic transport measurements with high energy resolution require both effective low-pass filtering of high-frequency input noise and an optimized thermalization of the electronic system of the experiment. In recent years, elaborate filter designs have been developed for cryogenic low-level measurements, driven by the growing interest in fundamental quantum-physical phenomena at energy scales corresponding to temperatures in the few millikelvin regime. However, a single filter concept is often insufficient to thermalize the electronic system to the cryogenic bath and eliminate spurious high frequency noise. Moreover, the available concepts often provide inadequate filtering to operate at temperatures below 10 mK, which are routinely available now in dilution cryogenic systems. Herein we provide a comprehensive analysis of commonly used filter types, introduce a novel compact filter type based on ferrite compounds optimized for the frequency range above 20 GHz, and develop an improved filtering scheme providing adaptable broad-band low-pass characteristic for cryogenic low-level and quantum measurement applications at temperatures down to few millikelvin.

  14. Dedusting and filtering technology; Entstaubungs- und Filtertechnik

    Energy Technology Data Exchange (ETDEWEB)

    Selck, S.; Stockmann, H.W.; Both, R. [Deutsche Montan Technologie GmbH, Essen (Germany). Gas and Fire Div.

    2004-07-01

    For the further development of the filtration and dedusting technology within the last research period the new regulations in occupational hygiene concerning dust as well as ISO and EN standards have been considered. Also the new requirements concerning fire and explosion protection filter materials based in the test regulations for synthetic materials have been taken into account. The adoption of these new regulations inhibits the further use of the available high effective filter materials in underground coal mines. The development of new filter materials has been forced by the test regulations for synthetic materials, as the specific aspects of electrostatic behaviour, soot and toxic gases formed by burning of filter materials impacting the CO self rescue filters, have been taken into account. Even these requirements are partially inhibiting high filter efficiencies and air flows, all the requirements have been fulfilled on a high level on filter efficiencies matching the present state of art in occupational hygiene as reported in the Silicosis Reports Vol. 20 and 21. (orig.)

  15. Paul Rodgersi filter Kohilas

    Index Scriptorium Estoniae

    2000-01-01

    28. I Kohila keskkoolis kohaspetsiifiline skulptuur ja performance "Filter". Kooli 130. aastapäeva tähistava ettevõtmise eesotsas oli skulptor Paul Rodgers ja kaks viimase klassi noormeest ئ Marko Heinmäe, Hendrik Karm.

  16. Perspectives on Nonlinear Filtering

    KAUST Repository

    Law, Kody

    2015-01-07

    The solution to the problem of nonlinear filtering may be given either as an estimate of the signal (and ideally some measure of concentration), or as a full posterior distribution. Similarly, one may evaluate the fidelity of the filter either by its ability to track the signal or its proximity to the posterior filtering distribution. Hence, the field enjoys a lively symbiosis between probability and control theory, and there are plenty of applications which benefit from algorithmic advances, from signal processing, to econometrics, to large-scale ocean, atmosphere, and climate modeling. This talk will survey some recent theoretical results involving accurate signal tracking with noise-free (degenerate) dynamics in high-dimensions (infinite, in principle, but say d between 103 and 108 , depending on the size of your application and your computer), and high-fidelity approximations of the filtering distribution in low dimensions (say d between 1 and several 10s).

  17. Updating the OMERACT filter

    DEFF Research Database (Denmark)

    D'Agostino, Maria-Antonietta; Boers, Maarten; Kirwan, John

    2014-01-01

    OBJECTIVE: The Outcome Measures in Rheumatology (OMERACT) Filter provides a framework for the validation of outcome measures for use in rheumatology clinical research. However, imaging and biochemical measures may face additional validation challenges because of their technical nature. The Imagin...

  18. Compact photonic spin filters

    Science.gov (United States)

    Ke, Yougang; Liu, Zhenxing; Liu, Yachao; Zhou, Junxiao; Shu, Weixing; Luo, Hailu; Wen, Shuangchun

    2016-10-01

    In this letter, we propose and experimentally demonstrate a compact photonic spin filter formed by integrating a Pancharatnam-Berry phase lens (focal length of ±f ) into a conventional plano-concave lens (focal length of -f). By choosing the input port of the filter, photons with a desired spin state, such as the right-handed component or the left-handed one, propagate alone its original propagation direction, while the unwanted spin component is quickly diverged after passing through the filter. One application of the filter, sorting the spin-dependent components of vector vortex beams on higher-order Poincaré sphere, is also demonstrated. Our scheme provides a simple method to manipulate light, and thereby enables potential applications for photonic devices.

  19. Filtered stochastic calculus

    OpenAIRE

    Lenczewski, Romuald

    2001-01-01

    By introducing a color filtration to the multiplicity space, we extend the quantum Ito calculus on multiple symmetric Fock space to the framework of filtered adapted biprocesses. In this new notion of adaptedness,``classical'' time filtration makes the integrands similar to adapted processes, whereas ``quantum'' color filtration produces their deviations from adaptedness. An important feature of this calculus, which we call filtered stochastic calculus, is that it provides an explicit interpo...

  20. Contactor/filter improvements

    Science.gov (United States)

    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.

  1. A modified LLCL-filter with the reduced conducted EMI noise

    DEFF Research Database (Denmark)

    Wu, Weimin; Sun, Yunjie; Lin, Zhe

    2014-01-01

    mode EMI noises are investigated for the LCL- and LLCL-filter-based single-phase full-bridge grid-tied inverters. Based on this, a modified LLCL-filter topology is proposed to provide enough attenuation on the conducted EMI noise as well as to reduce the dc-side leakage current. The parameter design...... method of the filter is also developed. The comparative analysis and discussion on four filter cases (the conventional LCL filter, the conventional LLCL filter, the modified LCL filter, and the modified LLCL filter) are carried out and verified through simulations and experiments on a 0.5-kW, 110 V/50 Hz...

  2. Reconfigurable Ring Filter with Controllable Frequency Response

    Directory of Open Access Journals (Sweden)

    Norfishah Ab Wahab

    2014-01-01

    Full Text Available Reconfigurable ring filter based on single-side-access ring topology is presented. Using capacitive tuning elements, the electrical length of the ring can be manipulated to shift the nominal center frequency to a desired position. A synthesis is developed to determine the values of the capacitive elements. To show the advantage of the synthesis, it is applied to the reconfigurable filter design using RF lumped capacitors. The concept is further explored by introducing varactor-diodes to continuously tune the center frequency of the ring filter. For demonstration, two prototypes of reconfigurable ring filters are realized using microstrip technology, simulated, and measured to validate the proposed concept. The reconfigured filter using lumped elements is successfully reconfigured from 2 GHz to 984.4 MHz and miniaturized by 71% compared to the filter directly designed at the same reconfigured frequency, while, for the filter using varactor-diodes, the frequency is chosen from 1.10 GHz to 1.38 GHz spreading over 280 MHz frequency range. Both designs are found to be compact with acceptable insertion loss and high selectivity.

  3. Digital filters principles and applications with MATLAB

    CERN Document Server

    Taylor, Fred J

    2012-01-01

    "The proposed book is not an exposition on digital signal processing (DSP) but rather a treatise on digital filters. The material and coverage is comprehensive, presented in a consistent style that first develops topics and subtopics in terms it their purpose, relationship to other core ideas, theoretical and conceptual framework, and finally instruction in the implementation of digital filter devices. Each major study is supported by Matlab-enabled activities and examples, with each Chapter culminating in a comprehensive design case study"--

  4. Choosing and using astronomical filters

    CERN Document Server

    Griffiths, Martin

    2014-01-01

    As a casual read through any of the major amateur astronomical magazines will demonstrate, there are filters available for all aspects of optical astronomy. This book provides a ready resource on the use of the following filters, among others, for observational astronomy or for imaging: Light pollution filters Planetary filters Solar filters Neutral density filters for Moon observation Deep-sky filters, for such objects as galaxies, nebulae and more Deep-sky objects can be imaged in much greater detail than was possible many years ago. Amateur astronomers can take

  5. Anti-Aliasing filter for reverse-time migration

    KAUST Repository

    Zhan, Ge

    2012-01-01

    We develop an anti-aliasing filter for reverse-time migration (RTM). It is similar to the traditional anti-aliasing filter used for Kirchhoff migration in that it low-pass filters the migration operator so that the dominant wavelength in the operator is greater than two times the trace sampling interval, except it is applied to both primary and multiple reflection events. Instead of applying this filter to the data in the traditional RTM operation, we apply the anti-aliasing filter to the generalized diffraction-stack migration operator. This gives the same migration image as computed by anti-aliased RTM. Download

  6. Filters for cathodic arc plasmas

    Science.gov (United States)

    Anders, Andre; MacGill, Robert A.; Bilek, Marcela M. M.; Brown, Ian G.

    2002-01-01

    Cathodic arc plasmas are contaminated with macroparticles. A variety of magnetic plasma filters has been used with various success in removing the macroparticles from the plasma. An open-architecture, bent solenoid filter, with additional field coils at the filter entrance and exit, improves macroparticle filtering. In particular, a double-bent filter that is twisted out of plane forms a very compact and efficient filter. The coil turns further have a flat cross-section to promote macroparticle reflection out of the filter volume. An output conditioning system formed of an expander coil, a straightener coil, and a homogenizer, may be used with the magnetic filter for expanding the filtered plasma beam to cover a larger area of the target. A cathodic arc plasma deposition system using this filter can be used for the deposition of ultrathin amorphous hard carbon (a-C) films for the magnetic storage industry.

  7. Sensory pollution from bag filters, carbon filters and combinations.

    Science.gov (United States)

    Bekö, G; Clausen, G; Weschler, C J

    2008-02-01

    Used ventilation filters are a major source of sensory pollutants in air handling systems. The objective of the present study was to evaluate the net effect that different combinations of filters had on perceived air quality after 5 months of continuous filtration of outdoor suburban air. A panel of 32 subjects assessed different sets of used filters and identical sets consisting of new filters. Additionally, filter weights and pressure drops were measured at the beginning and end of the operation period. The filter sets included single EU5 and EU7 fiberglass filters, an EU7 filter protected by an upstream pre-filter (changed monthly), an EU7 filter protected by an upstream activated carbon (AC) filter, and EU7 filters with an AC filter either downstream or both upstream and downstream. In addition, two types of stand-alone combination filters were evaluated: a bag-type fiberglass filter that contained AC and a synthetic fiber cartridge filter that contained AC. Air that had passed through used filters was most acceptable for those sets in which an AC filter was used downstream of the particle filter. Comparable air quality was achieved with the stand-alone bag filter that contained AC. Furthermore, its pressure drop changed very little during the 5 months of service, and it had the added benefit of removing a large fraction of ozone from the airstream. If similar results are obtained over a wider variety of soiling conditions, such filters may be a viable solution to a long recognized problem. The present study was designed to address the emission of sensory offending pollutants from loaded ventilation filters. The goal was to find a low-polluting solution from commercially available products. The results indicate that the use of activated carbon (AC) filters downstream of fiberglass bag filters can reduce the degradation of air quality that occurs with increasing particle loading. A more practical solution, yet comparably effective, is a stand-alone particle

  8. Multilevel ensemble Kalman filtering

    KAUST Repository

    Hoel, Haakon

    2016-01-08

    The ensemble Kalman filter (EnKF) is a sequential filtering method that uses an ensemble of particle paths to estimate the means and covariances required by the Kalman filter by the use of sample moments, i.e., the Monte Carlo method. EnKF is often both robust and efficient, but its performance may suffer in settings where the computational cost of accurate simulations of particles is high. The multilevel Monte Carlo method (MLMC) is an extension of classical Monte Carlo methods which by sampling stochastic realizations on a hierarchy of resolutions may reduce the computational cost of moment approximations by orders of magnitude. In this work we have combined the ideas of MLMC and EnKF to construct the multilevel ensemble Kalman filter (MLEnKF) for the setting of finite dimensional state and observation spaces. The main ideas of this method is to compute particle paths on a hierarchy of resolutions and to apply multilevel estimators on the ensemble hierarchy of particles to compute Kalman filter means and covariances. Theoretical results and a numerical study of the performance gains of MLEnKF over EnKF will be presented. Some ideas on the extension of MLEnKF to settings with infinite dimensional state spaces will also be presented.

  9. Multi-Configuration Matched Spectral Filter Core Project

    Data.gov (United States)

    National Aeronautics and Space Administration — OPTRA proposes the development of a modular, reconfigurable matched spectral filter (RMSF) spectrometer for the monitoring of greenhouse and volcanic gases. The...

  10. Filters for Submillimeter Electromagnetic Waves

    Science.gov (United States)

    Berdahl, C. M.

    1986-01-01

    New manufacturing process produces filters strong, yet have small, precise dimensions and smooth surface finish essential for dichroic filtering at submillimeter wavelengths. Many filters, each one essentially wafer containing fine metal grid made at same time. Stacked square wires plated, fused, and etched to form arrays of holes. Grid of nickel and tin held in brass ring. Wall thickness, thickness of filter (hole depth) and lateral hole dimensions all depend upon operating frequency and filter characteristics.

  11. Filtering algorithm for dotted interferences

    Energy Technology Data Exchange (ETDEWEB)

    Osterloh, K., E-mail: kurt.osterloh@bam.de [Federal Institute for Materials Research and Testing (BAM), Division VIII.3, Radiological Methods, Unter den Eichen 87, 12205 Berlin (Germany); Buecherl, T.; Lierse von Gostomski, Ch. [Technische Universitaet Muenchen, Lehrstuhl fuer Radiochemie, Walther-Meissner-Str. 3, 85748 Garching (Germany); Zscherpel, U.; Ewert, U. [Federal Institute for Materials Research and Testing (BAM), Division VIII.3, Radiological Methods, Unter den Eichen 87, 12205 Berlin (Germany); Bock, S. [Technische Universitaet Muenchen, Lehrstuhl fuer Radiochemie, Walther-Meissner-Str. 3, 85748 Garching (Germany)

    2011-09-21

    An algorithm has been developed to remove reliably dotted interferences impairing the perceptibility of objects within a radiographic image. This particularly is a major challenge encountered with neutron radiographs collected at the NECTAR facility, Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II): the resulting images are dominated by features resembling a snow flurry. These artefacts are caused by scattered neutrons, gamma radiation, cosmic radiation, etc. all hitting the detector CCD directly in spite of a sophisticated shielding. This makes such images rather useless for further direct evaluations. One approach to resolve this problem of these random effects would be to collect a vast number of single images, to combine them appropriately and to process them with common image filtering procedures. However, it has been shown that, e.g. median filtering, depending on the kernel size in the plane and/or the number of single shots to be combined, is either insufficient or tends to blur sharp lined structures. This inevitably makes a visually controlled processing image by image unavoidable. Particularly in tomographic studies, it would be by far too tedious to treat each single projection by this way. Alternatively, it would be not only more comfortable but also in many cases the only reasonable approach to filter a stack of images in a batch procedure to get rid of the disturbing interferences. The algorithm presented here meets all these requirements. It reliably frees the images from the snowy pattern described above without the loss of fine structures and without a general blurring of the image. It consists of an iterative, within a batch procedure parameter free filtering algorithm aiming to eliminate the often complex interfering artefacts while leaving the original information untouched as far as possible.

  12. Adaptive digital filters

    CERN Document Server

    Kovačević, Branko; Milosavljević, Milan

    2013-01-01

    “Adaptive Digital Filters” presents an important discipline applied to the domain of speech processing. The book first makes the reader acquainted with the basic terms of filtering and adaptive filtering, before introducing the field of advanced modern algorithms, some of which are contributed by the authors themselves. Working in the field of adaptive signal processing requires the use of complex mathematical tools. The book offers a detailed presentation of the mathematical models that is clear and consistent, an approach that allows everyone with a college level of mathematics knowledge to successfully follow the mathematical derivations and descriptions of algorithms.   The algorithms are presented in flow charts, which facilitates their practical implementation. The book presents many experimental results and treats the aspects of practical application of adaptive filtering in real systems, making it a valuable resource for both undergraduate and graduate students, and for all others interested in m...

  13. Automated electronic filter design

    CERN Document Server

    Banerjee, Amal

    2017-01-01

    This book describes a novel, efficient and powerful scheme for designing and evaluating the performance characteristics of any electronic filter designed with predefined specifications. The author explains techniques that enable readers to eliminate complicated manual, and thus error-prone and time-consuming, steps of traditional design techniques. The presentation includes demonstration of efficient automation, using an ANSI C language program, which accepts any filter design specification (e.g. Chebyschev low-pass filter, cut-off frequency, pass-band ripple etc.) as input and generates as output a SPICE(Simulation Program with Integrated Circuit Emphasis) format netlist. Readers then can use this netlist to run simulations with any version of the popular SPICE simulator, increasing accuracy of the final results, without violating any of the key principles of the traditional design scheme.

  14. Computer-Generated Holographic Matched Filters

    Science.gov (United States)

    Butler, Steven Frank

    This dissertation presents techniques for the use of computer-generated holograms (CGH) for matched filtering. An overview of the supporting technology is provided. Included are techniques for modifying existing CGH algorithms to serve as matched filters in an optical correlator. It shows that matched filters produced in this fashion can be modified to improve the signal-to-noise and efficiency over that possible with conventional holography. The effect and performance of these modifications are demonstrated. In addition, a correction of film non-linearity in continuous -tone filter production is developed. Computer simulations provide quantitative and qualitative demonstration of theoretical principles, with specific examples validated in optical hardware. Conventional and synthetic holograms, both bleached and unbleached, are compared.

  15. Filters in topology optimization

    DEFF Research Database (Denmark)

    Bourdin, Blaise

    1999-01-01

    In this article, a modified (``filtered'') version of the minimum compliance topology optimization problem is studied. The direct dependence of the material properties on its pointwise density is replaced by a regularization of the density field using a convolution operator. In this setting...... it is possible to establish the existence of solutions. Moreover, convergence of an approximation by means of finite elements can be obtained. This is illustrated through some numerical experiments. The ``filtering'' technique is also shown to cope with two important numerical problems in topology optimization...

  16. A PC Controlled Filter

    Directory of Open Access Journals (Sweden)

    M. Van Looy

    1998-12-01

    Full Text Available In this paper we present a switched capacitor filter design using the SC22324 1C, which is fitted with an E2PROM. It contains four digitally programmable switched-capacitor filter sections, in order to obtain different responses. The SC22324 also contains the on-chip RAM. We'd like to explain, how could the on-chip RAM controlled via a PC. In this way the chip may be used afterwards with a menu where the user may select the wanted parameters.

  17. Parzen Particle Filters

    DEFF Research Database (Denmark)

    Lehn-Schiøler, Tue; Erdogmus, Deniz; Principe, Jose C.

    2004-01-01

    Using a Parzen density estimator any distribution can be approximated arbitrarily close by a sum of kernels. In particle filtering this fact is utilized to estimate a probability density function with Dirac delta kernels; when the distribution is discretized it becomes possible to solve an otherw......Using a Parzen density estimator any distribution can be approximated arbitrarily close by a sum of kernels. In particle filtering this fact is utilized to estimate a probability density function with Dirac delta kernels; when the distribution is discretized it becomes possible to solve...

  18. A superior edge preserving filter with a systematic analysis

    Science.gov (United States)

    Holladay, Kenneth W.; Rickman, Doug

    1991-01-01

    A new, adaptive, edge preserving filter for use in image processing is presented. It had superior performance when compared to other filters. Termed the contiguous K-average, it aggregates pixels by examining all pixels contiguous to an existing cluster and adding the pixel closest to the mean of the existing cluster. The process is iterated until K pixels were accumulated. Rather than simply compare the visual results of processing with this operator to other filters, some approaches were developed which allow quantitative evaluation of how well and filter performs. Particular attention is given to the standard deviation of noise within a feature and the stability of imagery under iterative processing. Demonstrations illustrate the performance of several filters to discriminate against noise and retain edges, the effect of filtering as a preprocessing step, and the utility of the contiguous K-average filter when used with remote sensing data.

  19. Enhanced Optical Filter Design

    CERN Document Server

    Cushing, David

    2011-01-01

    This book serves as a supplement to the classic texts by Angus Macleod and Philip Baumeister, taking an intuitive approach to the enhancement of optical coating (or filter) performance. Drawing from 40 years of experience in thin film design, Cushing introduces the basics of thin films, the commonly used materials and their deposition, the major coatings and their applications, and improvement methods for each.

  20. The ATLAS event filter

    CERN Document Server

    Beck, H P; Boissat, C; Davis, R; Duval, P Y; Etienne, F; Fede, E; Francis, D; Green, P; Hemmer, F; Jones, R; MacKinnon, J; Mapelli, Livio P; Meessen, C; Mommsen, R K; Mornacchi, Giuseppe; Nacasch, R; Negri, A; Pinfold, James L; Polesello, G; Qian, Z; Rafflin, C; Scannicchio, D A; Stanescu, C; Touchard, F; Vercesi, V

    1999-01-01

    An overview of the studies for the ATLAS Event Filter is given. The architecture and the high level design of the DAQ-1 prototype is presented. The current status if the prototypes is briefly given. Finally, future plans and milestones are given. (11 refs).

  1. Sand Filter Technology

    Science.gov (United States)

    2016-08-01

    EXWC) performed the evaluation at the Naval Air Station Lemoore, CA . The two year evaluation period began with one year of sand filter operation...appear dirty? If you answered “ yes ” to the first question and “ yes ” to either of the other questions, investigate this technology for your

  2. Fast Anisotropic Gauss Filters

    NARCIS (Netherlands)

    Geusebroek, J.M.; Smeulders, A.W.M.; van de Weijer, J.

    2003-01-01

    We derive the decomposition of the anisotropic Gaussian in a one dimensional Gauss filter in the x-direction phi. So also the anisotropic Gaussian can be decomposed by dimension. This appears to be extremely efficient from a computing perspective. An implementation scheme for normal covolution and

  3. Underwater Sound Filtering

    NARCIS (Netherlands)

    Rutger van Aalst; Ines Simic

    2015-01-01

    This paper describes a possible solution to the underwater sound filtering problem, using Blind Source Separation. The problem regards splitting sound from a boat engine and the water waves to prove the possibility to extract one sound fragment from the other on the open sea. The illustrations shown

  4. Choosing and using methodological search filters: searchers' views.

    Science.gov (United States)

    Beale, Sophie; Duffy, Steven; Glanville, Julie; Lefebvre, Carol; Wright, Dianne; McCool, Rachael; Varley, Danielle; Boachie, Charles; Fraser, Cynthia; Harbour, Jenny; Smith, Lynne

    2014-06-01

    Search filters or hedges are search strategies developed to assist information specialists and librarians to retrieve different types of evidence from bibliographic databases. The objectives of this project were to learn about searchers' filter use, how searchers choose search filters and what information they would like to receive to inform their choices. Interviews with information specialists working in, or for, the National Institute for Health and Care Excellence (NICE) were conducted. An online questionnaire survey was also conducted and advertised via a range of email lists. Sixteen interviews were undertaken and 90 completed questionnaires were received. The use of search filters tends to be linked to reducing a large amount of literature, introducing focus and assisting with searches that are based on a single study type. Respondents use numerous ways to identify search filters and can find choosing between different filters problematic because of knowledge gaps and lack of time. Search filters are used mainly for reducing large result sets (introducing focus) and assisting with searches focused on a single study type. Features that would help with choosing filters include making information about filters less technical, offering ratings and providing more detail about filter validation strategies and filter provenance. © 2014 The authors. Health Information and Libraries Journal © 2014 Health Libraries Group.

  5. DEMONSTRATION BULLETIN: COLLOID POLISHING FILTER METHOD - FILTER FLOW TECHNOLOGY, INC.

    Science.gov (United States)

    The Filter Flow Technology, Inc. (FFT) Colloid Polishing Filter Method (CPFM) was tested as a transportable, trailer mounted, system that uses sorption and chemical complexing phenomena to remove heavy metals and nontritium radionuclides from water. Contaminated waters can be pro...

  6. Comparison between analog and digital filters

    Directory of Open Access Journals (Sweden)

    Zoltan Erdei

    2010-12-01

    Full Text Available Digital signal processing(DSP is one of the most powerful technologies and will model science and engineering in the 21st century. Revolutionary changes have already been made in different areas of research such as communications, medical imaging, radar and sonar technology, high fidelity audio signal reproducing etc. Each of these fields developed a different signal processing technology with its own algorithms, mathematics and technology, Digital filters are used in two general directions: to separate mixed signals and to restore signals that were compromised in different modes. The objective of this paper is to compare some basic digital filters versus analog filters such as low-pass, high-pass, band-pass filters. Scientists and engineers comprehend that, in comparison with analog filters, digital filters can process the same signal in real-time with broader flexibility. This understanding is considered important to instill incentive for engineers to become interested in the field of DSP. The analysis of the results will be made using dedicated libraries in MATLAB and Simulink software, such as the Signal Processing Toolbox.

  7. Molecular circuits for dynamic noise filtering.

    Science.gov (United States)

    Zechner, Christoph; Seelig, Georg; Rullan, Marc; Khammash, Mustafa

    2016-04-26

    The invention of the Kalman filter is a crowning achievement of filtering theory-one that has revolutionized technology in countless ways. By dealing effectively with noise, the Kalman filter has enabled various applications in positioning, navigation, control, and telecommunications. In the emerging field of synthetic biology, noise and context dependency are among the key challenges facing the successful implementation of reliable, complex, and scalable synthetic circuits. Although substantial further advancement in the field may very well rely on effectively addressing these issues, a principled protocol to deal with noise-as provided by the Kalman filter-remains completely missing. Here we develop an optimal filtering theory that is suitable for noisy biochemical networks. We show how the resulting filters can be implemented at the molecular level and provide various simulations related to estimation, system identification, and noise cancellation problems. We demonstrate our approach in vitro using DNA strand displacement cascades as well as in vivo using flow cytometry measurements of a light-inducible circuit in Escherichia coli.

  8. Feature-Based Nonlocal Polarimetric SAR Filtering

    Directory of Open Access Journals (Sweden)

    Xiaoli Xing

    2017-10-01

    Full Text Available Polarimetric synthetic aperture radar (PolSAR images are inherently contaminated by multiplicative speckle noise, which complicates the image interpretation and image analyses. To reduce the speckle effect, several adaptive speckle filters have been developed based on the weighted average of the similarity measures commonly depending on the model or probability distribution, which are often affected by the distribution parameters and modeling texture components. In this paper, a novel filtering method introduces the coefficient of variance ( CV and Pauli basis (PB to measure the similarity, and the two features are combined with the framework of the nonlocal mean filtering. The CV is used to describe the complexity of various scenes and distinguish the scene heterogeneity; moreover, the Pauli basis is able to express the polarimetric information in PolSAR image processing. This proposed filtering combines the CV and Pauli basis to improve the estimation accuracy of the similarity weights. Then, the similarity of the features is deduced according to the test statistic. Subsequently, the filtering is proceeded by using the nonlocal weighted estimation. The performance of the proposed filter is tested with the simulated images and real PolSAR images, which are acquired by AIRSAR system and ESAR system. The qualitative and quantitative experiments indicate the validity of the proposed method by comparing with the widely-used despeckling methods.

  9. In-place HEPA filter penetration test

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, W.; Wilson, K.; Elliott, J. [Lawrence Livermore National Lab., CA (United States)] [and others

    1997-08-01

    We have demonstrated the feasibility of conducting penetration tests on high efficiency particulate air (HEPA) filters as installed in nuclear ventilation systems. The in-place penetration test, which is designed to yield equivalent penetration measurements as the standard DOP efficiency test, is based on measuring the aerosol penetration of the filter installation as a function of particle size using a portable laser particle counter. This in-place penetration test is compared to the current in-place leak test using light scattering photometers for single HEPA filter installations and for HEPA filter plenums using the shroud method. Test results show the in-place penetration test is more sensitive than the in-place leak test, has a similar operating procedure, but takes longer to conduct. Additional tests are required to confirm that the in-place penetration test yields identical results as the standard dioctyl phthalate (DOP) penetration test for HEPA filters with controlled leaks in the filter and gasket and duct by-pass leaks. Further development of the procedure is also required to reduce the test time before the in-place penetration test is practical. 14 refs., 14 figs., 3 tabs.

  10. Numerical study of canister filters with alternatives filter cap configurations

    Science.gov (United States)

    Mohammed, A. N.; Daud, A. R.; Abdullah, K.; Seri, S. M.; Razali, M. A.; Hushim, M. F.; Khalid, A.

    2017-09-01

    Air filtration system and filter play an important role in getting a good quality air into turbo machinery such as gas turbine. The filtration system and filter has improved the quality of air and protect the gas turbine part from contaminants which could bring damage. During separation of contaminants from the air, pressure drop cannot be avoided but it can be minimized thus helps to reduce the intake losses of the engine [1]. This study is focused on the configuration of the filter in order to obtain the minimal pressure drop along the filter. The configuration used is the basic filter geometry provided by Salutary Avenue Manufacturing Sdn Bhd. and two modified canister filter cap which is designed based on the basic filter model. The geometries of the filter are generated by using SOLIDWORKS software and Computational Fluid Dynamics (CFD) software is used to analyse and simulates the flow through the filter. In this study, the parameters of the inlet velocity are 0.032 m/s, 0.063 m/s, 0.094 m/s and 0.126 m/s. The total pressure drop produce by basic, modified filter 1 and 2 is 292.3 Pa, 251.11 Pa and 274.7 Pa. The pressure drop reduction for the modified filter 1 is 41.19 Pa and 14.1% lower compared to basic filter and the pressure drop reduction for modified filter 2 is 17.6 Pa and 6.02% lower compared to the basic filter. The pressure drops for the basic filter are slightly different with the Salutary Avenue filter due to limited data and experiment details. CFD software are very reliable in running a simulation rather than produces the prototypes and conduct the experiment thus reducing overall time and cost in this study.

  11. FPGA implementation of filtered image using 2D Gaussian filter

    OpenAIRE

    Leila kabbai; Anissa Sghaier; Ali Douik; Mohsen Machhout

    2016-01-01

    Image filtering is one of the very useful techniques in image processing and computer vision. It is used to eliminate useless details and noise from an image. In this paper, a hardware implementation of image filtered using 2D Gaussian Filter will be present. The Gaussian filter architecture will be described using a different way to implement convolution module. Thus, multiplication is in the heart of convolution module, for this reason, three different ways to implement multiplication opera...

  12. Generalized Selection Weighted Vector Filters

    Directory of Open Access Journals (Sweden)

    Rastislav Lukac

    2004-09-01

    Full Text Available This paper introduces a class of nonlinear multichannel filters capable of removing impulsive noise in color images. The here-proposed generalized selection weighted vector filter class constitutes a powerful filtering framework for multichannel signal processing. Previously defined multichannel filters such as vector median filter, basic vector directional filter, directional-distance filter, weighted vector median filters, and weighted vector directional filters are treated from a global viewpoint using the proposed framework. Robust order-statistic concepts and increased degree of freedom in filter design make the proposed method attractive for a variety of applications. Introduced multichannel sigmoidal adaptation of the filter parameters and its modifications allow to accommodate the filter parameters to varying signal and noise statistics. Simulation studies reported in this paper indicate that the proposed filter class is computationally attractive, yields excellent performance, and is able to preserve fine details and color information while efficiently suppressing impulsive noise. This paper is an extended version of the paper by Lukac et al. presented at the 2003 IEEE-EURASIP Workshop on Nonlinear Signal and Image Processing (NSIP '03 in Grado, Italy.

  13. NONDESTRUCTIVE EVALUATION OF CERAMIC CANDLE FILTERS

    Energy Technology Data Exchange (ETDEWEB)

    Roger H.L. Chen, Ph.D.; Alejandro Kiriakidis

    1999-09-01

    Nondestructive evaluation (NDE) techniques have been used to reduce the potential mechanical failures and to improve the reliability of a structure. Failure of a structure is usually initiated at some type of flaw in the material. NDE techniques have been developed to determine the presence of flaws larger than an acceptable size and to estimate the remaining stiffness of a damaged structure (Chen, et. al, 1995). Ceramic candle filters have been tested for use in coal-fueled gas turbine systems. They protect gas turbine components from damage due to erosion. A total of one hundred and one candle filters were nondestructively evaluated in this study. Ninety-eight ceramic candle filters and three ceramic composite filters have been nondestructively inspected using dynamic characterization technique. These ceramic filters include twelve unused Coors alumina/mullite, twenty-four unused and fifteen used Schumacher-Dia-Schumalith TF-20, twenty-five unused and nine used Refractron 326, eight unused and three used Refractron 442T, one new Schumacher-T 10-20, and one used Schumacher-Dia-Schumalith F-40. All filters were subjected to a small excitation and the dynamic response was picked up by a piezoelectric accelerometer. The evaluation of experimental results was processed using digital signal analysis technique including various forms of data transformation. The modal parameters for damage assessment for the unexposed (unused) vs. exposed (used) specimen were based on two vibration parameters: natural frequencies and mode shapes. Finite Element models were built for each specimen type to understand its dynamic response. Linear elastic modal analysis was performed using eight nodes, three-dimensional isotropic solid elements. Conclusions based on our study indicate that dynamic characterization is a feasible NDE technique in studying structural properties of ceramic candle filters. It has been shown that the degradation of the filters due to long working hours (or

  14. MEDOF - MINIMUM EUCLIDEAN DISTANCE OPTIMAL FILTER

    Science.gov (United States)

    Barton, R. S.

    1994-01-01

    values of amplitude and phase for the k whose metric was largest, as well as consistency checks, are reported. A finer search can be done in the neighborhood of the optimal k if desired. The filter finally selected is written to disk in terms of drive values, not in terms of the filter's complex transmittance. Optionally, the impulse response of the filter may be created to permit users to examine the response for the features the algorithm deems important to the recognition process under the selected metric, limitations of the filter SLM, etc. MEDOF uses the filter SLM to its greatest potential, therefore filter competence is not compromised for simplicity of computation. MEDOF is written in C-language for Sun series computers running SunOS. With slight modifications, it has been implemented on DEC VAX series computers using the DEC-C v3.30 compiler, although the documentation does not currently support this platform. MEDOF can also be compiled using Borland International Inc.'s Turbo C++ v1.0, but IBM PC memory restrictions greatly reduce the maximum size of the reference images from which the filters can be calculated. MEDOF requires a two dimensional Fast Fourier Transform (2DFFT). One 2DFFT routine which has been used successfully with MEDOF is a routine found in "Numerical Recipes in C: The Art of Scientific Programming," which is available from Cambridge University Press, New Rochelle, NY 10801. The standard distribution medium for MEDOF is a .25 inch streaming magnetic tape cartridge (Sun QIC-24) in UNIX tar format. MEDOF was developed in 1992-1993.

  15. Simulation for noise cancellation using LMS adaptive filter

    Science.gov (United States)

    Lee, Jia-Haw; Ooi, Lu-Ean; Ko, Ying-Hao; Teoh, Choe-Yung

    2017-06-01

    In this paper, the fundamental algorithm of noise cancellation, Least Mean Square (LMS) algorithm is studied and enhanced with adaptive filter. The simulation of the noise cancellation using LMS adaptive filter algorithm is developed. The noise corrupted speech signal and the engine noise signal are used as inputs for LMS adaptive filter algorithm. The filtered signal is compared to the original noise-free speech signal in order to highlight the level of attenuation of the noise signal. The result shows that the noise signal is successfully canceled by the developed adaptive filter. The difference of the noise-free speech signal and filtered signal are calculated and the outcome implies that the filtered signal is approaching the noise-free speech signal upon the adaptive filtering. The frequency range of the successfully canceled noise by the LMS adaptive filter algorithm is determined by performing Fast Fourier Transform (FFT) on the signals. The LMS adaptive filter algorithm shows significant noise cancellation at lower frequency range.

  16. Hydrodynamics of microbial filter feeding

    DEFF Research Database (Denmark)

    Nielsen, Lasse Tor; Asadzadeh, Seyed Saeed; Dölger, Julia

    2017-01-01

    Microbial filter feeders are an important group of grazers, significant to the microbial loop, aquatic food webs, and biogeochemical cycling. Our understanding of microbial filter feeding is poor, and, importantly, it is unknown what force microbial filter feeders must generate to process adequate...... amounts of water. Also, the trade-off in the filter spacing remains unexplored, despite its simple formulation: A filter too coarse will allow suitably sized prey to pass unintercepted, whereas a filter too fine will cause strong flow resistance. We quantify the feeding flow of the filter......-feeding choanoflagellate Diaphanoeca grandis using particle tracking, and demonstrate that the current understanding of microbial filter feeding is inconsistent with computational fluid dynamics (CFD) and analytical estimates. Both approaches underestimate observed filtration rates by more than an order of magnitude...

  17. Very High Speed Discrete Time Optical Signal Generation and Filtering

    Science.gov (United States)

    Narayan, Vishwa

    Optical lattice filters constitute a class of devices that generate and operate upon high bandwidth optical signals. This dissertation describes the design, analysis, construction and testing of such devices. We derive elegant z-transform based filter transfer functions and develop a convenient state variable based scattering matrix filter description. A variety of filters are designed and analyzed. We also design locally optimal optical lattice filters with mirror imperfections such as losses and finite reflectivity round-off error. We conduct a quantitative sensitivity analysis of the degrading effects of these imperfections on system performance, and study the distorting effects of phase error on pulse train shape. Experimentally, we use mirror based optical lattice filters to generate 667 GHz repetition rate pulse bursts with step and ramp envelopes, and coded pulse bursts. We also demonstrate the quadrupling and octupling of the 76 MHz repetition rate of a mode-locked laser. We demonstrate the low pass filtering property of optical lattice filters by realizing a high speed discrete time optical integrator. Step functions are integrated to ramps, and ramps to quadratics, at 667 GHz. We also constructed a mechanical variable repetition rate filter with a tuning range of 2.14 to 100 GHz. We design and analyze a gain based mirror filter with active gain elements. Small signal linear constant gain tends to improve filter performance by increasing the output, and reducing fluctuations in the frequency response. We study the behavior of these filters at the stability limit, characterized by large fluctuations in the frequency response. Optical lattice filters may be used as wavelength multiplexers/demultiplexers in lightwave systems, as variable repetition rate pulse train generators for tunable repetition rate optical spectroscopy, as optical clock generators, and as discrete time/analog optical signal filters.

  18. Model for optimising the execution of anti-spam filters

    Directory of Open Access Journals (Sweden)

    David Ruano-Ordás

    2016-12-01

    Full Text Available During last years, the combination of several filtering techniques for the development of anti-spam systems has gained a enormous popularity. However, although the accuracy achieved by these models has increased considerably, its use has entailed the emergence of new challenges such as the need to reduce the excessive use of computational resources, the increase of filtering speed and the adjustment of the weights used for the combination of several filtering techniques. In order to achieve this goal we have been refined several aspects including: (i the design and development of small technical improvements to increase the overall performance of the filter, (ii application of genetic algorithms to increase filtering accuracy and (iii the use of scheduling algorithms to improve filtering throughput.

  19. Dust removal and filter technology. Entstaubungs- und Filtertechnik

    Energy Technology Data Exchange (ETDEWEB)

    Stockmann, H.W. (DMT-Gesellschaft fuer Forschung und Pruefung mbH, Essen (Germany). DMT-Institut fuer Staubbekaempfung, Gefahrstoffe und Ergonomie); Henke, B. (DMT-Gesellschaft fuer Forschung und Pruefung mbH, Essen (Germany). DMT-Institut fuer Staubbekaempfung, Gefahrstoffe und Ergonomie)

    1991-01-01

    New approaches were adopted in filter technology to respond to technological changes in mechanized mining and to allow perfect dust removal in keeping with occupational hygiene requirements. Self-supporting filter materials based on ceramic fibres and synthetic granulates were taken to develop filter elements allowing lamination to enhance their separation-active surface area. Filter materials made from thermally fixed fibre nonwovens were processed to form plicated filter bags of the same structural volume but with a surface area increased by a factor of 2.5. Integrated inlet nozzles were developed to allow these elements to be cleaned of dust deposits. These nozzles were also studied in basic filter-technology tests. A test rig supplied design findings which were included in a study to develop new generations of dedusters. A reduction of design volume and an increase of through-put rate greater than 20% could be predicted. Service tests with modified filter materials were run for ventilation-air dust dust removal both for whole faces and for face segments. The benefits of filter technology for face, face opening and drifting were highlighted. New methods for wetting and transport of the dust removed from the dedusters were developed. New concepts of exhaust-air filter separators allow flat storage bunkers to be used in pneumatic conveyance of building materials at the face. (orig.)

  20. The Rao-Blackwellized Particle Filter: A Filter Bank Implementation

    Directory of Open Access Journals (Sweden)

    Karlsson Rickard

    2010-01-01

    Full Text Available For computational efficiency, it is important to utilize model structure in particle filtering. One of the most important cases occurs when there exists a linear Gaussian substructure, which can be efficiently handled by Kalman filters. This is the standard formulation of the Rao-Blackwellized particle filter (RBPF. This contribution suggests an alternative formulation of this well-known result that facilitates reuse of standard filtering components and which is also suitable for object-oriented programming. Our RBPF formulation can be seen as a Kalman filter bank with stochastic branching and pruning.

  1. Multilevel particle filter

    KAUST Repository

    Law, Kody

    2016-01-06

    This talk will pertain to the filtering of partially observed diffusions, with discrete-time observations. It is assumed that only biased approximations of the diffusion can be obtained, for choice of an accuracy parameter indexed by l. A multilevel estimator is proposed, consisting of a telescopic sum of increment estimators associated to the successive levels. The work associated to O( 2) mean-square error between the multilevel estimator and average with respect to the filtering distribution is shown to scale optimally, for example as O( 2) for optimal rates of convergence of the underlying diffusion approximation. The method is illustrated on some toy examples as well as estimation of interest rate based on real S&P 500 stock price data.

  2. Particle flow superpositional GLMB filter

    Science.gov (United States)

    Saucan, Augustin-Alexandru; Li, Yunpeng; Coates, Mark

    2017-05-01

    In this paper we propose a Superpositional Marginalized δ-GLMB (SMδ-GLMB) filter for multi-target tracking and we provide bootstrap and particle flow particle filter implementations. Particle filter implementations of the marginalized δ-GLMB filter are computationally demanding. As a first contribution we show that for the specific case of superpositional observation models, a reduced complexity update step can be achieved by employing a superpositional change of variables. The resulting SMδ-GLMB filter can be readily implemented using the unscented Kalman filter or particle filtering methods. As a second contribution, we employ particle flow to produce a measurement-driven importance distribution that serves as a proposal in the SMδ-GLMB particle filter. In high-dimensional state systems or for highly- informative observations the generic particle filter often suffers from weight degeneracy or otherwise requires a prohibitively large number of particles. Particle flow avoids particle weight degeneracy by guiding particles to regions where the posterior is significant. Numerical simulations showcase the reduced complexity and improved performance of the bootstrap SMδ-GLMB filter with respect to the bootstrap Mδ-GLMB filter. The particle flow SMδ-GLMB filter further improves the accuracy of track estimates for highly informative measurements.

  3. Manipulation Robustness of Collaborative Filtering

    OpenAIRE

    Benjamin Van Roy; Xiang Yan

    2010-01-01

    A collaborative filtering system recommends to users products that similar users like. Collaborative filtering systems influence purchase decisions and hence have become targets of manipulation by unscrupulous vendors. We demonstrate that nearest neighbors algorithms, which are widely used in commercial systems, are highly susceptible to manipulation and introduce new collaborative filtering algorithms that are relatively robust.

  4. Popping the filter bubble

    OpenAIRE

    Hughes, Katie; Cronin, G; Welch, L

    2017-01-01

    So-called “fake news” is everywhere and is having a major impact on daily life from politics to education. The rapid growth of information and the numbers of people who can create it means that we need more sophisticated tools to process the news we receive. Join us to learn about different methods you can use to be your own fact checker and pop your filter bubble.

  5. Offsetting the Affective Filter

    Directory of Open Access Journals (Sweden)

    Barry Chametzky, PhD

    2017-06-01

    Full Text Available When forced to deal with a stressful, unfamiliar situation, how do people react? People are familiar, in a traditional setting, with sensory overload. But in an online environment, when learners are anxious, they exhibit different behaviors to help mediate their anxiety. Additionally, in an online environment, since visual clues are often lacking, how do these behaviors manifest themselves? People navigate stressful and/or unfamiliar situations by offsetting their affective filter.

  6. Filter Bank Fusion Frames

    OpenAIRE

    Chebira, Amina; Fickus, Matthew; Mixon, Dustin G.

    2010-01-01

    In this paper we characterize and construct novel oversampled filter banks implementing fusion frames. A fusion frame is a sequence of orthogonal projection operators whose sum can be inverted in a numerically stable way. When properly designed, fusion frames can provide redundant encodings of signals which are optimally robust against certain types of noise and erasures. However, up to this point, few implementable constructions of such frames were known; we show how to construct them using ...

  7. Developing a Small-Scale De-Fluoridation Filter for Use in Rural Northern Ghana with Activated Alumina As the Sorbent

    Science.gov (United States)

    Craig, L.; Stillings, L. L.

    2014-12-01

    In northern Ghana, groundwater is the main source of household water and is generally considered safe to drink. However in some areas it contains fluoride (F-) concentrations above the 1.5 ppm limit recommended by the World Health Organization, putting the users at risk of fluorosis. The study area in the Upper East Region of Ghana has pockets of groundwater F- up to 4.6 ppm and, as a result, also has a high percentage of residents with dental fluorosis. They have no alternative water source and, because of poverty and limited access to technology, lack the capacity to set up advanced treatment systems. One proposed solution is to attach F- adsorption filters to the wells, since adsorption is considered a simple and cost effective approach for treating high F-drinking water. This study evaluates activated alumina as a sorbent for use in de-fluoridation filters in the study area. We evaluated the long-term adsorption capacity of activated alumina, and changes in F- adsorption rate and capacity with grain size. We measured differences in positive surface charge (C m-2) via slow acid titration, as well as F- loading with varied prior hydration time. Results from this research show no notable change in F- adsorption or positive surface charge when the activated alumina surface was pre-equilibrated in distilled water from 24 hours to 30 weeks. The results of F- loading show a maximum of ~3.4 mg F- sorbed per gm activated alumina (initial pH ~6.9, initial F- 1 to 60 ppm, 20 hr reaction time). The pH dependent surface charge is ~0.14 C m-2 at pH of ~4.4 and is zero at pH ~8.6. F- loading experiments were conducted with grain size 0.125 to 0.250 mm and 0.5 to 1.0 mm to evaluate changes in F- adsorption rate (initial pH ~6.9, initial F- 10 ppm) and F- loading (initial pH ~6.9, initial F- 1 to 60 ppm, 20 hr reaction time). The F- loading did not change with grain size. However time to equilibrium increased dramatically with a decrease in grain size - after one hour of

  8. Recursive Robot-Arm Dynamics via Filtering and Smoothing

    Science.gov (United States)

    Rodriguez, Guillermo

    1987-01-01

    Forward and inverse dynamics solved using Kalman filtering and Bryson-Frazier smoothing. Dynamics of serial-link robot arm solved by using recursive techniques from linear filtering and smoothing theory. Solutions of dynamical equations give forces, moments, and accelerations at joints between links, and multilink inertia matrix and its inverse. Theoretical developments lay foundation for use of filtering and smoothing techniques in design of robot controls.

  9. Tunable Microwave Filter Design Using Thin-Film Ferroelectric Varactors

    Science.gov (United States)

    Haridasan, Vrinda

    Military, space, and consumer-based communication markets alike are moving towards multi-functional, multi-mode, and portable transceiver units. Ferroelectric-based tunable filter designs in RF front-ends are a relatively new area of research that provides a potential solution to support wideband and compact transceiver units. This work presents design methodologies developed to optimize a tunable filter design for system-level integration, and to improve the performance of a ferroelectric-based tunable bandpass filter. An investigative approach to find the origins of high insertion loss exhibited by these filters is also undertaken. A system-aware design guideline and figure of merit for ferroelectric-based tunable band- pass filters is developed. The guideline does not constrain the filter bandwidth as long as it falls within the range of the analog bandwidth of a system's analog to digital converter. A figure of merit (FOM) that optimizes filter design for a specific application is presented. It considers the worst-case filter performance parameters and a tuning sensitivity term that captures the relation between frequency tunability and the underlying material tunability. A non-tunable parasitic fringe capacitance associated with ferroelectric-based planar capacitors is confirmed by simulated and measured results. The fringe capacitance is an appreciable proportion of the tunable capacitance at frequencies of X-band and higher. As ferroelectric-based tunable capac- itors form tunable resonators in the filter design, a proportionally higher fringe capacitance reduces the capacitance tunability which in turn reduces the frequency tunability of the filter. Methods to reduce the fringe capacitance can thus increase frequency tunability or indirectly reduce the filter insertion-loss by trading off the increased tunability achieved to lower loss. A new two-pole tunable filter topology with high frequency tunability (> 30%), steep filter skirts, wide stopband

  10. Development of New Fluorescence Instrument for extended Deep-UV to NIR Excitation-Emission Matrices with Simultaneous Absorbance and Inner-Filter Effect Correction

    Science.gov (United States)

    Gilmore, A. M.

    2013-12-01

    Characterization of dissolved organic matter components, including humic and fulvic acids, chlorophyll and algae, oils and proteins, among others, using fluorescence excitation-emission matrices (EEMs) is now widely accepted due to the rapidly afforded high-sensitivity and selectivity. However, to date no single instrument has been able to effectively cover the entire spectral range from 200 nm to over 800 nm and also facilitate the simultaneous absorbance spectral acquisition required for correcting the concentration dependent inner filter effects that can distort the quantification of the fluorescence signal. The new instrument uses a UV-enhanced light source coupled to a scanning double grating monochromator for the full UV-NIR absorbance and fluorescence excitation scanning as well as a UV to NIR sensitive CCD-spectrograph for rapid fluorescence emission detection. Both the absorbance and fluorescence detection are uniquely corrected using an optically and kinetically coordinated reference detector system. Other major problems solved for the long-range scanning for EEMs include 1) the removal of second order light from the excitation path which is accomplished using an automated filter wheel and 2) masking of the higher order emission bands which is accomplished by effective software masking. A key feature of the system is the facilitation of continuous ';on-the-fly' processing of the NIST traceable corrected fluorescence and absorbance data for immediate multivariate processing to support several commercially available packages for parallel factor analysis (PARAFAC) and principal component analysis (PCA). Several examples of qualitative and quantitative analyses with the system will be explained including: 1) measuring natural organic matter components associated with disinfection by-product formation in drinking water treatment and fouling permeates of filtration membranes, 2) measuring chlorophyll spectra associated with classification of algal species

  11. Diesel particulate filter design simulation: A review

    Directory of Open Access Journals (Sweden)

    Shichun Yang

    2016-03-01

    Full Text Available Simulation is a powerful tool in the design and analysis of diesel particulate filters. Various models have been developed in the last three decades and great improvements have been made in terms of model comprehensiveness and accuracy. However, simulation of diesel particulate filter is still not a reliable resort to fine-tuning of diesel particulate filter and much effort is still needed. To promote the development of effective simulation models, first, the various models are viewed. Their characteristics and application occasions are discussed. Second, regarding the limitations of these models, some key submodels are introduced, which are pressure drop model in the wall, filtration model, and soot oxidation model. Finally, some conclusions are made and further researches are recommended.

  12. A class of quaternion Kalman filters.

    Science.gov (United States)

    Jahanchahi, Cyrus; Mandic, Danilo P

    2014-03-01

    The existing Kalman filters for quaternion-valued signals do not operate fully in the quaternion domain, and are combined with the real Kalman filter to enable the tracking in 3-D spaces. Using the recently introduced HR-calculus, we develop the fully quaternion-valued Kalman filter (QKF) and quaternion-extended Kalman filter (QEKF), allowing for the tracking of 3-D and 4-D signals directly in the quaternion domain. To consider the second-order noncircularity of signals, we employ the recently developed augmented quaternion statistics to derive the widely linear QKF (WL-QKF) and widely linear QEKF (WL-QEKF). To reduce computational requirements of the widely linear algorithms, their efficient implementation are proposed and it is shown that the quaternion widely linear model can be simplified when processing 3-D data, further reducing the computational requirements. Simulations using both synthetic and real-world circular and noncircular signals illustrate the advantages offered by widely linear over strictly linear quaternion Kalman filters.

  13. Varactor-tuned Substrate Integrated Evanescent Filter

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Acar, Öncel; Dong, Yunfeng

    Evanescent mode waveguides allow for more compact microwave component design in comparison to the traditional fundamental mode waveguide technology. Evanescent waveguides can be integrated into a dielectric substrate in order to further reduce the mass and volume. Unfortunately, traditional reali......, fabricated and tested in order to validate the developed filter models as well as the implemented realization method. The filter structure as well as its tuning are shown in Figure 1....... is considered. In contrast to other methods described in the literature, it avoids etching split ring resonators in the metal layer of the SIW. The filters presented here use varactors as tuning elements. The varactors (as well as DC decoupling circuits) are mounted on the surface of PCB bringing the lower...... metal layer of the waveguide to the top layer with metalized via holes. The present filters are analyzed using models based on impedance matrix representation. The developed models allow computationally efficient and relatively accurate prediction of the filter behavior in a wide frequency range (at...

  14. Power Systems Development Facility

    Energy Technology Data Exchange (ETDEWEB)

    Southern Company Services

    2009-01-31

    In support of technology development to utilize coal for efficient, affordable, and environmentally clean power generation, the Power Systems Development Facility (PSDF), located in Wilsonville, Alabama, has routinely demonstrated gasification technologies using various types of coals. The PSDF is an engineering scale demonstration of key features of advanced coal-fired power systems, including a Transport Gasifier, a hot gas particulate control device, advanced syngas cleanup systems, and high-pressure solids handling systems. This final report summarizes the results of the technology development work conducted at the PSDF through January 31, 2009. Twenty-one major gasification test campaigns were completed, for a total of more than 11,000 hours of gasification operation. This operational experience has led to significant advancements in gasification technologies.

  15. Wiener filter for filtered back projection in digital breast tomosynthesis

    Science.gov (United States)

    Wang, Xinying; Mainprize, James G.; Wu, Gang; Yaffe, Martin J.

    2012-03-01

    Conventional filtered back projection (FBP) reconstruction for digital breast tomosynthesis (DBT) can suffer from a low signal to noise ratio. Because of the strong amplification by the reconstruction filters (ramp, apodization and slice thickness), noise at high spatial frequencies can be greatly increased. Image enhancement by Wiener filtering is investigated as a possible method to improve image quality. A neighborhood wavelet coefficient window technique is used to estimate the noise content of projection images and a Wiener filter is applied to the projection images. The neighborhood wavelet coefficient window is a non-linear technique, which may cause the Wiener filters estimated before and after the application of the reconstruction filters to be different. Image quality of a FBP reconstruction with and without Wiener filtering is investigated using a Fourier-based observer detectability metric ( d' ) for evaluation. Simulations of tomosynthesis are performed in both homogeneous and anatomic textured backgrounds containing lowcontrast masses or small microcalcifications. Initial results suggest that improvements in detectability can be achieved when the Wiener filter is applied, especially when the Wiener filter is estimated for the reconstruction filtered projections.

  16. LLCL-Filtered Grid Converter with Improved Stability and Robustness

    DEFF Research Database (Denmark)

    Min, Huang; Wang, Xiongfei; Loh, Poh Chiang

    2016-01-01

    LLCL-filter has been proven to introduce more filtering at the converter switching frequency, while using smaller passive components. However, like other higher order filters, it introduces resonance to the grid when used with a grid converter. Its stability and robustness are also affected by grid...... method even with no damping added to the grid converter. The method has been applied to the development of an LLCL-filter for testing in the laboratory with a 5-kW, 400-V, and 50-Hz grid converter. The method can also be applied to the lower order LCL-filter with only a slight modification needed....... impedance variations, making its design more challenging. To address these concerns, a new parameter design method for LLCL-filter has been formulated in the paper, which when enforced, guarantees robust and stable grid current control regardless of how the grid conditions change. It is thus an enhanced...

  17. Distributed Kalman-Consensus Filtering for Sparse Signal Estimation

    Directory of Open Access Journals (Sweden)

    Yisha Liu

    2014-01-01

    Full Text Available A Kalman filtering-based distributed algorithm is proposed to deal with the sparse signal estimation problem. The pseudomeasurement-embedded Kalman filter is rebuilt in the information form, and an improved parameter selection approach is discussed. By introducing the pseudomeasurement technology into Kalman-consensus filter, a distributed estimation algorithm is developed to fuse the measurements from different nodes in the network, such that all filters can reach a consensus on the estimate of sparse signals. Some numerical examples are provided to demonstrate the effectiveness of the proposed approach.

  18. Impulse control in Kalman-like filtering problems

    Directory of Open Access Journals (Sweden)

    Michael V. Basin

    1998-01-01

    Full Text Available This paper develops the impulse control approach to the observation process in Kalman-like filtering problems, which is based on impulsive modeling of the transition matrix in an observation equation. The impulse control generates the jumps of the estimate variance from its current position down to zero and, as a result, enables us to obtain the filtering equations for the Kalman estimate with zero variance for all post-jump time moments. The filtering equations for the estimates with zero variances are obtained in the conventional linear filtering problem and in the case of scalar nonlinear state and nonlinear observation equations.

  19. Modular, Parallel Pulse-Shaping Filter Architectures

    Science.gov (United States)

    Gray, Andrew A.

    2003-01-01

    Novel architectures based on parallel subconvolution frequency-domain filtering methods have been developed for modular processing rate reduction of discrete-time pulse-shaping filters. Such pulse-shaping is desirable and often necessary to obtain bandwidth efficiency in very-high-rate wireless communications systems. In principle, this processing could be implemented in very-large-scale integrated (VLSI) circuits. Whereas other approaches to digital pulse-shaping are based primarily on time-domain processing concepts, the theory and design rules of the architectures presented here are founded on frequency-domain processing that has advantages in certain systems.

  20. Restricted Kalman Filtering Theory, Methods, and Application

    CERN Document Server

    Pizzinga, Adrian

    2012-01-01

    In statistics, the Kalman filter is a mathematical method whose purpose is to use a series of measurements observed over time, containing random variations and other inaccuracies, and produce estimates that tend to be closer to the true unknown values than those that would be based on a single measurement alone. This Brief offers developments on Kalman filtering subject to general linear constraints. There are essentially three types of contributions: new proofs for results already established; new results within the subject; and applications in investment analysis and macroeconomics, where th

  1. Live Convolution with Time-Varying Filters

    Directory of Open Access Journals (Sweden)

    Øyvind Brandtsegg

    2018-01-01

    Full Text Available The paper presents two new approaches to artefact-free real-time updates of the impulse response in convolution. Both approaches are based on incremental updates of the filter. This can be useful for several applications within digital audio processing: parametrisation of convolution reverbs, dynamic filters, and live convolution. The development of these techniques has been done within the framework of a research project on crossadaptive audio processing methods for live performance. Our main motivation has thus been live convolution, where the signals from two music performers are convolved with each other, allowing the musicians to “play through each other’s sound”.

  2. Superconducting notch filter

    Energy Technology Data Exchange (ETDEWEB)

    Pang, C S; Falco, C M; Kampwirth, R T; Schuller, I K; Hudak, J J; Anastasio, T A

    1979-01-01

    Results of a preliminary investigation of a superconducting notch filter for possible application in the 2 to 30 MHz high frequency (HF) communication band are presented. The circuit was successfully implemented using planar geometry so that closed cycle refrigeration could be used to cool circuits fabricated from high T/sub c/ Nb/sub 3/Sn or Nb/sub 3/Ge thin films. In the present design, circuit Q's of about 2 x 10/sup 3/ were obtained with 50-ohm source and output impedance. (TFD)

  3. Spindoktorer et politisk filter

    OpenAIRE

    Talic, Elvedin; Bernt, Rune; Mortensen, Mass Holmegård

    2015-01-01

    Through the TV and other media, many rumors about what a spin-doctor does and the nature of his services have spread. We would like to clarify the function; role and influence the spin-doctor have on Danish politics. We will look specifically at the relationship of power between the Ministers and spin-doctors, and the spin-doctors and media, as some believe that the spin-doctor sometimes will rise to power. We will also take look at the filter function between spin-doctors and media, as it is...

  4. Multilevel ensemble Kalman filtering

    KAUST Repository

    Hoel, Hakon

    2016-06-14

    This work embeds a multilevel Monte Carlo sampling strategy into the Monte Carlo step of the ensemble Kalman filter (EnKF) in the setting of finite dimensional signal evolution and noisy discrete-time observations. The signal dynamics is assumed to be governed by a stochastic differential equation (SDE), and a hierarchy of time grids is introduced for multilevel numerical integration of that SDE. The resulting multilevel EnKF is proved to asymptotically outperform EnKF in terms of computational cost versus approximation accuracy. The theoretical results are illustrated numerically.

  5. Charcoal filter testing

    Energy Technology Data Exchange (ETDEWEB)

    Lyons, J. [Nuclear Regulatory Commission, Washington, DC (United States)

    1997-08-01

    In this very brief, informal presentation, a representative of the US Nuclear Regulatory Commission outlines some problems with charcoal filter testing procedures and actions being taken to correct the problems. Two primary concerns are addressed: (1) the process to find the test method is confusing, and (2) the requirements of the reference test procedures result in condensation on the charcoal and causes the test to fail. To address these problems, emergency technical specifications were processed for three nuclear plants. A generic or an administrative letter is proposed as a more permanent solution. 1 fig.

  6. The optimum sunglass filter?

    Science.gov (United States)

    Soederberg, Per G.; Michael, Ralph; Ayala, Marcelo; Wu, Jiangmei; Loefgren, Stefan; Merriam, John; Chen, Enping

    1999-06-01

    It is concluded that sunglasses shall block UVR and toxic blue light, allow transmittance of signal light and bring luminous intensity behind the filters to a comfortable level. It was found that some commercially available sunglasses, apart from one pair of photochromatic dark state lenses tested, block ultraviolet radiation (UVR) adequately. Further, it was found that it is possible to block the toxic blue radiation without interfering substantially on blue signal light perception. However, none of the sunglasses tested blocked the toxic blue light enough.

  7. Digital Filters for Low Frequency Equalization

    DEFF Research Database (Denmark)

    Tyril, Marni; Abildgaard, J.; Rubak, Per

    2001-01-01

    Digital filters with high resolution in the low-frequency range are studied. Specifically, for a given computational power, traditional IIR filters are compared with warped FIR filters, warped IIR filters, and modified warped FIR filters termed warped individual z FIR filters (WizFIR). The results...

  8. HEPA filter fire (and subsequent unfiltered release)

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, G.W., Westinghouse Hanford

    1996-08-12

    This document supports the development and presentation of the following accident scenario in the TWRS Final Safety Analysis Report: HEPA Filter Failure - Exposure to High Temperature or Pressure. The calculations needed to quantify the risk associated with this accident scenario are included within.

  9. implementation of spatial domain homomorphic filtering

    African Journals Online (AJOL)

    eobe

    There is a lot of background literature on frequency- domain Homomorphic ... developed in the literature [4-6, 8-9]. This paper ..... Processing times for spatial and frequency domain filter. Colour Image Dimensions Spatial domain processing time(s) Frequency domainprocessing time(s). Girl. 256 × 256. 0.058. 0.914. Swan.

  10. HEPA filter fire (and subsequent unfiltered release)

    Energy Technology Data Exchange (ETDEWEB)

    Powers, T.B.

    1996-09-27

    This document supports the development and presentation of the following accident scenario in the TWRS Final Safety Analysis Report: HEPA Filter Failure - Exposure to High Temperature or Pressure. The calculations needed to quantify the risk associated with this accident scenario are included within.

  11. Target detection by way of Kalman filtering

    Science.gov (United States)

    Sipe, Gary A.

    1993-03-01

    A simple, time domain method is used to analyze moderate to high PRF radar signals. The quantities of interest are the signal's PRF, SNR, and time of arrival. The time of arrival problem is important because it can be used, with multiple sensors, to determine the position of the emitting target. An algorithm is described which will produce these values using Kalman filtering. Individual pulses in a pulsed type radar are measured against a threshold using a two sample detection scheme to provide some glitch rejection. Results of individual time domain measurements of the signal parameter are smoothed with a Kalman filter. Integrating the pulse train envelope during the radar dwell time provides the energy centroid for a scan cycle. This centroid, time differenced with multiple sensors, provides observables for an Extended Kalman Filter for emitter localization. The work here simulates all data. Tests of the algorithms developed were conducted on real, classified data in addition to the work presented here.

  12. High flow ceramic pot filters.

    Science.gov (United States)

    van Halem, D; van der Laan, H; Soppe, A I A; Heijman, S G J

    2017-11-01

    Ceramic pot filters are considered safe, robust and appropriate technologies, but there is a general consensus that water revenues are limited due to clogging of the ceramic element. The objective of this study was to investigate the potential of high flow ceramic pot filters to produce more water without sacrificing their microbial removal efficacy. High flow pot filters, produced by increasing the rice husk content, had a higher initial flow rate (6-19 L h-1), but initial LRVs for E. coli of high flow filters was slightly lower than for regular ceramic pot filters. This disadvantage was, however, only temporarily as the clogging in high flow filters had a positive effect on the LRV for E. coli (from below 1 to 2-3 after clogging). Therefore, it can be carefully concluded that regular ceramic pot filters perform better initially, but after clogging, the high flow filters have a higher flow rate as well as a higher LRV for E. coli. To improve the initial performance of new high flow filters, it is recommended to further utilize residence time of the water in the receptacle, since additional E. coli inactivation was observed during overnight storage. Although a relationship was observed between flow rate and LRV of MS2 bacteriophages, both regular and high flow filters were unable to reach over 2 LRV. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. From Microwave Filter to Digital Filter and Back Again

    DEFF Research Database (Denmark)

    Dalby, Arne Brejning

    1989-01-01

    A new very simple state variable flow graph representation for interdigital transmission line bandpass filters is presented, which has led to two important results: 1) A new type of digital filter with properties, that surpass the properties of most other (all pole) digital filtertypes. 2......) The study of the new digital filtertype has led to design formulas for interdigital transmission line filters that are very simple compared to the hitherto known formulas. The accuracy is the same or better....

  14. Recent Techniques in Design and Implementation of Microwave Planar Filters

    OpenAIRE

    P.K. Singhal; Baral, R. N.

    2008-01-01

    This paper details the techniques and initiatives made recently for improved response and simultaneous development of microwave planar filters. Although the objective of all the techniques is to design low cost filters with reduced dimensions, compact size with better frequency response, the methodological approaches are quite variant. The paper has gone through extensive analysis of all these techniques, their concept and design procedures.

  15. A low-loss, continuously tunable microwave notch filter

    DEFF Research Database (Denmark)

    Acar, Öncel; Johansen, Tom Keinicke; Zhurbenko, Vitaliy

    2016-01-01

    The development in high-end microwave transceiver systems toward the software defined radio has brought about the need for tunable frontend filters. Although the problem is being tackled by the microwave community, there still appears to be an unmet demand for practical tunable filter technologies...

  16. Explicit filtering of building blocks for genetic algorithms

    NARCIS (Netherlands)

    C.H.M. van Kemenade

    1996-01-01

    textabstractGenetic algorithms are often applied to building block problems. We have developed a simple filtering algorithm that can locate building blocks within a bit-string, and does not make assumptions regarding the linkage of the bits. A comparison between the filtering algorithm and genetic

  17. Predicting the efficiency of deposit removal during filter backwash

    African Journals Online (AJOL)

    The long-term performance of granular media filters used in drinking water treatment is ultimately limited by the efficiency of the backwash process. This paper demonstrates that it is possible to develop quantitative predictions of backwash efficiency based on filter operating conditions. An experimental investigation into the ...

  18. DSP Control of Line Hybrid Active Filter

    DEFF Research Database (Denmark)

    Dan, Stan George; Benjamin, Doniga Daniel; Magureanu, R.

    2005-01-01

    Active Power Filters have been intensively explored in the past decade. Hybrid active filters inherit the efficiency of passive filters and the improved performance of active filters, and thus constitute a viable improved approach for harmonic compensation. In this paper a parallel hybrid filter ...... active filter. Simulation and experimental results obtained in laboratory confirmed the validity and effectiveness of the control.......Active Power Filters have been intensively explored in the past decade. Hybrid active filters inherit the efficiency of passive filters and the improved performance of active filters, and thus constitute a viable improved approach for harmonic compensation. In this paper a parallel hybrid filter...... is studied for current harmonic compensation. The hybrid filter is formed by a single tuned Le filter and a small-rated power active filter, which are directly connected in series without any matching transformer. Thus the required rating of the active filter is much smaller than a conventional standalone...

  19. Filter and Filter Bank Design for Image Texture Recognition

    Energy Technology Data Exchange (ETDEWEB)

    Randen, Trygve

    1997-12-31

    The relevance of this thesis to energy and environment lies in its application to remote sensing such as for instance sea floor mapping and seismic pattern recognition. The focus is on the design of two-dimensional filters for feature extraction, segmentation, and classification of digital images with textural content. The features are extracted by filtering with a linear filter and estimating the local energy in the filter response. The thesis gives a review covering broadly most previous approaches to texture feature extraction and continues with proposals of some new techniques. 143 refs., 59 figs., 7 tabs.

  20. Tandem HEPA filter tests.

    Science.gov (United States)

    Schuster, B G; Osetek, D J

    1978-02-01

    Current methods for evaluating the performance and reliability of high-efficiency air cleaning systems use forward light-scattering photometers and DOP aerosol. This method is limited to measuring protection factors of 10(4) or 10(5) and has poor sensitivity to particles less than .3 micron. More accurate determination of system performance could be made by measuring two filter stages with a single test. Because of the large protection factors of a two-stage system, it is necessary to use high challenge aerosol concentrations and long downstream sampling times. Concentrations were measured using an intra-cavity laser light-scattering aerosol spectrometer which is capable of detection of single particles ranging in size from 0.07 to 3.00 micron diameter. The results of several tests with challenge aerosols of both NaCl and DOP yielded protection factors ranging from 1.4 x 10(7) to 3.0 x 10(9) for two HEPA filters in series.

  1. Validation of search filters for identifying pediatric studies in PubMed

    NARCIS (Netherlands)

    Leclercq, Edith; Leeflang, Mariska M. G.; van Dalen, Elvira C.; Kremer, Leontien C. M.

    2013-01-01

    To identify and validate PubMed search filters for retrieving studies including children and to develop a new pediatric search filter for PubMed. We developed 2 different datasets of studies to evaluate the performance of the identified pediatric search filters, expressed in terms of sensitivity,

  2. Ceramic High Efficiency Particulate Air (HEPA) Filter Final Report CRADA No. TC02160.0

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bergman, W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-08-25

    The technical objective of this project was to develop a ceramic HEPA filter technology, by initially producing and testing coupon ceramics, small scale prototypes, and full scale prototype HEPA filters, and to address relevant manufacturing and commercialization technical issues.

  3. Artificial neural network (ANN)-based prediction of depth filter loading capacity for filter sizing.

    Science.gov (United States)

    Agarwal, Harshit; Rathore, Anurag S; Hadpe, Sandeep Ramesh; Alva, Solomon J

    2016-11-01

    This article presents an application of artificial neural network (ANN) modelling towards prediction of depth filter loading capacity for clarification of a monoclonal antibody (mAb) product during commercial manufacturing. The effect of operating parameters on filter loading capacity was evaluated based on the analysis of change in the differential pressure (DP) as a function of time. The proposed ANN model uses inlet stream properties (feed turbidity, feed cell count, feed cell viability), flux, and time to predict the corresponding DP. The ANN contained a single output layer with ten neurons in hidden layer and employed a sigmoidal activation function. This network was trained with 174 training points, 37 validation points, and 37 test points. Further, a pressure cut-off of 1.1 bar was used for sizing the filter area required under each operating condition. The modelling results showed that there was excellent agreement between the predicted and experimental data with a regression coefficient (R2 ) of 0.98. The developed ANN model was used for performing variable depth filter sizing for different clarification lots. Monte-Carlo simulation was performed to estimate the cost savings by using different filter areas for different clarification lots rather than using the same filter area. A 10% saving in cost of goods was obtained for this operation. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1436-1443, 2016. © 2016 American Institute of Chemical Engineers.

  4. Spatial filters for high average power lasers

    Science.gov (United States)

    Erlandson, Alvin C

    2012-11-27

    A spatial filter includes a first filter element and a second filter element overlapping with the first filter element. The first filter element includes a first pair of cylindrical lenses separated by a first distance. Each of the first pair of cylindrical lenses has a first focal length. The first filter element also includes a first slit filter positioned between the first pair of cylindrical lenses. The second filter element includes a second pair of cylindrical lenses separated by a second distance. Each of the second pair of cylindrical lenses has a second focal length. The second filter element also includes a second slit filter positioned between the second pair of cylindrical lenses.

  5. Investigation of Locally Made Ceramic Filter for Household Water Treatment

    Directory of Open Access Journals (Sweden)

    Awaluddin Nurmiyanto

    2012-06-01

    Full Text Available This research have objective to develop and evaluate the performance of ceramic filter in using locally available material at Yogyakarta. Ceramic filter are made by pressing a mixture of clay, discarded pottery (grog and combustible material (coconut fiber into the molder. Curving processes are then applied to form tubular shape before firing it using kiln (1005°C. Filtration test were performed gravitationally by flowing well water into ceramic filter. Filtered water quality was complying with Indonesia drinking water quality standard (E.Coli and turbidity although it has low filtration rate (0,461 L/Hr. The most optimum ceramic filter in turbidity and bacterial removal was composition number 10 {clay+coconut fiber 4,5%(w/w+grog 5%(w/w} that have average turbidity removal 88,2%, and average E. Coli removal 100%. N2 adsorption-desorption result on ceramic filter number 10 showed 0,04μm pore size, and 4,32m2/g pore surface area. The result from the XRD (X-ray diffractometer indicates crystal structure of calcite and quartz on ceramic filter surface. Energy Dispersive X-ray (EDX analysis showed Carbon compound as the most material constituent within the filter. Whereas micro’s photo using SEM (scanning electron microscopic and TEM (transmitted electron microscopic showed filter surface consists of stacked aggregates, separated by more randomly oriented particles.

  6. Note: cryogenic coaxial microwave filters.

    Science.gov (United States)

    Tancredi, G; Schmidlin, S; Meeson, P J

    2014-02-01

    The careful filtering of microwave electromagnetic radiation is critical for controlling the electromagnetic environment for experiments in solid-state quantum information processing and quantum metrology at millikelvin temperatures. We describe the design and fabrication of a coaxial filter assembly and demonstrate that its performance is in excellent agreement with theoretical modelling. We further perform an indicative test of the operation of the filters by making current-voltage measurements of small, underdamped Josephson junctions at 15 mK.

  7. Multi-filter spectrophotometry simulations

    Science.gov (United States)

    Callaghan, Kim A. S.; Gibson, Brad K.; Hickson, Paul

    1993-01-01

    To complement both the multi-filter observations of quasar environments described in these proceedings, as well as the proposed UBC 2.7 m Liquid Mirror Telescope (LMT) redshift survey, we have initiated a program of simulated multi-filter spectrophotometry. The goal of this work, still very much in progress, is a better quantitative assessment of the multiband technique as a viable mechanism for obtaining useful redshift and morphological class information from large scale multi-filter surveys.

  8. Faraday anomalous dispersion optical filters

    Science.gov (United States)

    Shay, T. M.; Yin, B.; Alvarez, L. S.

    1993-01-01

    The effect of Faraday anomalous dispersion optical filters on infrared and blue transitions of some alkali atoms is calculated. A composite system is designed to further increase the background noise rejection. The measured results of the solar background rejection and image quality through the filter are presented. The results show that the filter may provide high transmission and high background noise rejection with excellent image quality.

  9. Hot Gas TVC For Planetary Ascent Vehicle Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A Mars ascent vehicle (MAV) uses solid rocket motors to propel soil samples into orbit, but the motors cannot provide steering. Cold gas thrusters are used for...

  10. Origin of the hot gas in low-mass protostars

    DEFF Research Database (Denmark)

    Van Kempen, T. A.; Kristensen, L. E.; Herczeg, G. J.

    2010-01-01

    Aims. "Water In Star-forming regions with Herschel" (WISH) is a Herschel key programme aimed at understanding the physical and chemical structure of young stellar objects (YSOs) with a focus on water and related species. Methods. The low-mass protostar HH 46 was observed with the Photodetector Ar...

  11. Hot Gas TVC For Planetary Ascent Vehicle Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A Mars ascent vehicle (MAV) uses solid rocket motors to propel soil samples into orbit, but the motors cannot provide steering. Flexseal TVC control is planned for...

  12. Theoretical modelling of hot gas ingestion through turbine rim seals

    Directory of Open Access Journals (Sweden)

    J. Michael Owen

    2012-12-01

    The nozzle guide vanes create three-dimensional (3D variations in the distribution of pressure in the mainstream annulus and the turbine blades create unsteady effects. Computational fluid dynamics (CFD is both time-consuming and expensive for these 3D unsteady flows, and engine designers tend to use correlations or simple models to predict ingress. This paper describes the application of simple ‘orifice models’, the analytical solutions of which can be used to calculate the sealing effectiveness of turbine rim seals. The solutions agree well with available data for externally-induced ingress, where the effects of rotation are negligible, for rotationally-induced ingress, where the effects of the external flow are small, and for combined ingress, where the effects of both external flow and rotation are significant.

  13. ADVANCED SULFUR CONTROL CONCEPTS FOR HOT-GAS DESULFURIZATION TECHNOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    A. LOPEZ ORTIZ; D.P. HARRISON; F.R. GROVES; J.D. WHITE; S. ZHANG; W.-N. HUANG; Y. ZENG

    1998-10-31

    This research project examined the feasibility of a second generation high-temperature coal gas desulfurization process in which elemental sulfur is produced directly during the sorbent regeneration phase. Two concepts were evaluated experimentally. In the first, FeS was regenerated in a H2O-O2 mixture. Large fractions of the sulfur were liberated in elemental form when the H2O-O2 ratio was large. However, the mole percent of elemental sulfur in the product was always quite small (<<1%) and a process based on this concept was judged to be impractical because of the low temperature and high energy requirements associated with condensing the sulfur. The second concept involved desulfurization using CeO2 and regeneration of the sulfided sorbent, Ce2O2S, using SO2 to produce elemental sulfur directly. No significant side reactions were observed and the reaction was found to be quite rapid over the temperature range of 500°C to 700°C. Elemental sulfur concentrations (as S2) as large as 20 mol% were produced. Limitations associated with the cerium sorbent process are concentrated in the desulfurization phase. High temperature and highly reducing coal gas such as produced in the Shell gasification process are required if high sulfur removal efficiencies are to be achieved. For example, the equilibrium H2S concentration at 800°C from a Shell gas in contact with CeO2 is about 300 ppmv, well above the allowable IGCC specification. In this case, a two-stage desulfurization process using CeO2 for bulk H2S removal following by a zinc sorbent polishing step would be required. Under appropriate conditions, however, CeO2 can be reduced to non-stoichiometric CeOn (n<2) which has significantly greater affinity for H2S. Pre-breakthrough H2S concentrations in the range of 1 ppmv to 5 ppmv were measured in sulfidation tests using CeOn at 700°C in highly reducing gases, as measured by equilibrium O2 concentration, comparable to the Shell gas. Good sorbent durability was indicated in a twenty-five-cycle test. The sorbent was exposed for 58 consecutive days to temperatures between 600°C and 800°C and gas atmospheres from highly reducing to highly oxidizing without measurable loss of sulfur capacity or reactivity. In the process analysis phase of this study, a two-stage desulfurization process using cerium sorbent with SO2 regeneration followed by zinc sorbent with dilute O2 regeneration was compared to a single-stage process using zinc sorbent and O2 regeneration with SO2 in the regeneration product gas converted to elemental sulfur using the direct sulfur recovery process (DSRP). Material and energy balances were calculated using the process simulation package PRO/II. Major process equipment was sized and a preliminary economic analysis completed. Sorbent replacement rate, which is determined by the multicycle sorbent durability, was found to be the most significant factor in both processes. For large replacement rates corresponding to average sorbent lifetimes of 250 cycles or less, the single-stage zinc sorbent process with DSRP was estimated to be less costly. However, the cost of the two-stage cerium sorbent process was more sensitive to sorbent replacement rate, and, as the required replacement rate decreased, the economics of the two-stage process improved. For small sorbent replacement rates corresponding to average sorbent lifetimes of 1000 cycles or more, the two-stage cerium process was estimated to be less costly. In the relatively wide middle range of sorbent replacement rates, the relative economics of the two processes depends on other factors such as the unit cost of sorbents, oxygen, nitrogen, and the relative capital costs.

  14. Hot gas handling device and motorized vehicle comprising the device

    NARCIS (Netherlands)

    Klein Geltink, J.; Beukers, A.; Van Tooren, M.J.L.; Koussios, S.

    2012-01-01

    The invention relates to a device for handling hot exhaust gasses discharged from an internal combustion engine. The device comprises a housing (2), enclosing a space (3) for transporting the exhaust gasses. The housing (2) is provided with an entrance - opening (4) for the exhaust gasses discharged

  15. Hot gas flow cell for optical measurements on reactive gases

    DEFF Research Database (Denmark)

    Grosch, Helge; Fateev, Alexander; Nielsen, Karsten Lindorff

    2013-01-01

    was validated for high resolution measurements at temperatures of up to 800 K (527 degrees C) in the ultraviolet (UV) and infrared (IR) regions (190-20 000 nm). Verification of the gas temperature in the cell is provided by a thermocouple and emission/transmission measurements in the IR and UV regions. High......-resolution measurements are presented for the absorption cross-section of sulfur dioxide (SO2) in the UV range up to 773 K (500 degrees C)...

  16. Transient Heating and Thermomechanical Stress Modeling of Ceramic HEPA Filters

    Energy Technology Data Exchange (ETDEWEB)

    Bogle, Brandon [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kelly, James [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Haslam, Jeffrey [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-09-29

    The purpose of this report is to showcase an initial finite-element analysis model of a ceramic High-Efficiency Particulate (HEPA) Air filter design. Next generation HEPA filter assemblies are being developed at LLNL to withstand high-temperature fire scenarios by use of ceramics and advanced materials. The filters are meant for use in radiological and nuclear facilities, and are required to survive 500°C fires over an hour duration. During such conditions, however, collecting data under varying parameters can be challenging; therefore, a Finite Element Analysis model of the filter was conducted using COMSOL ® Multiphysics to analyze the effects of fire. Finite Element Analysis (FEA) modelling offers several opportunities: researchers can quickly and easily consider impacts of potential design changes, material selection, and flow characterization on filter performance. Specifically, this model provides stress references for the sealant at high temperatures. Modeling of full filter assemblies was deemed inefficient given the computational requirements, so a section of three tubes from the assembly was modeled. The model looked at the transient heating and thermomechanical stress development during a 500°C air flow at 6 CFM. Significant stresses were found at the ceramic-metal interfaces of the filter, and conservative temperature profiles at locations of interest were plotted. The model can be used for the development of sealants that minimize stresses at the ceramic-metal interface. Further work on the model would include the full filter assembly and consider heat losses to make more accurate predictions.

  17. Adaptive filtering and change detection

    CERN Document Server

    Gustafsson, Fredrik

    2003-01-01

    Adaptive filtering is a classical branch of digital signal processing (DSP). Industrial interest in adaptive filtering grows continuously with the increase in computer performance that allows ever more conplex algorithms to be run in real-time. Change detection is a type of adaptive filtering for non-stationary signals and is also the basic tool in fault detection and diagnosis. Often considered as separate subjects Adaptive Filtering and Change Detection bridges a gap in the literature with a unified treatment of these areas, emphasizing that change detection is a natural extensi

  18. Kalman filter estimation of RLC parameters for UMP transmission line

    Directory of Open Access Journals (Sweden)

    Mohd Amin Siti Nur Aishah

    2018-01-01

    Full Text Available This paper present the development of Kalman filter that allows evaluation in the estimation of resistance (R, inductance (L, and capacitance (C values for Universiti Malaysia Pahang (UMP short transmission line. To overcome the weaknesses of existing system such as power losses in the transmission line, Kalman Filter can be a better solution to estimate the parameters. The aim of this paper is to estimate RLC values by using Kalman filter that in the end can increase the system efficiency in UMP. In this research, matlab simulink model is developed to analyse the UMP short transmission line by considering different noise conditions to reprint certain unknown parameters which are difficult to predict. The data is then used for comparison purposes between calculated and estimated values. The results have illustrated that the Kalman Filter estimate accurately the RLC parameters with less error. The comparison of accuracy between Kalman Filter and Least Square method is also presented to evaluate their performances.

  19. Bridging the ensemble Kalman filter and particle filters

    Energy Technology Data Exchange (ETDEWEB)

    Stordal, Andreas Stoerksen; Karlsen, Hans A.; Naevdal, Geir; Skaug, Hans J.; Valles, Brice

    2009-12-15

    The nonlinear filtering problem occurs in many scientific areas. Sequential Monte Carlo solutions with the correct asymptotic behavior such as particle filters exist but they are computationally too expensive when working with high-dimensional systems. The ensemble Kalman filter is a more robust method that has shown promising results with a small sample size but the samples are not guaranteed to come from the true posterior distribution. By approximating the model error with Gaussian kernels we get the advantage of both a Kalman correction and a weighting step. The resulting Gaussian mixture filter has the advantage of both a local Kalman type correction and the weighting/re sampling step of a particle filter. The Gaussian mixture approximation relies on a tunable bandwidth parameter which often has to be kept quite large in order to avoid weight collapse in high dimensions. As a result, the Kalman correction is too large to capture highly non-Gaussian posterior distributions. In this paper we have extended the Gaussian mixture filter (Hoteit et al., 2008b) and also made the connection to particle filters more transparent. In particular we introduce a tuning parameter for the importance weights. In the last part of the paper we have performed a simulation experiment with the Lorenz40 model where our method has been compared to the EnKF and a full implementation of a particle filter. The results clearly indicate that the new method has advantages compared to the standard EnKF. (Author)

  20. Kalman Filter Desing, Smoothing and Analysis

    OpenAIRE

    Cederkvist, Henrik Rene

    2001-01-01

    Thesis is based on three different aspects of Kalman filtering. >Kalman filters for navigation. Investigate the difference between a Extended Kalman Filter and a Linearized Kalman Filter with feedback. And show how different system models relate to these Kalman Filters when implemented in a filter. >Smoothing. Investigate how much there is to be gained from smoothing. We will only look at the fixed-interval smoother, using the method of forward and backward filtering. ...

  1. Particle Kalman Filtering: A Nonlinear Framework for Ensemble Kalman Filters

    KAUST Repository

    Hoteit, Ibrahim

    2010-09-19

    Optimal nonlinear filtering consists of sequentially determining the conditional probability distribution functions (pdf) of the system state, given the information of the dynamical and measurement processes and the previous measurements. Once the pdfs are obtained, one can determine different estimates, for instance, the minimum variance estimate, or the maximum a posteriori estimate, of the system state. It can be shown that, many filters, including the Kalman filter (KF) and the particle filter (PF), can be derived based on this sequential Bayesian estimation framework. In this contribution, we present a Gaussian mixture‐based framework, called the particle Kalman filter (PKF), and discuss how the different EnKF methods can be derived as simplified variants of the PKF. We also discuss approaches to reducing the computational burden of the PKF in order to make it suitable for complex geosciences applications. We use the strongly nonlinear Lorenz‐96 model to illustrate the performance of the PKF.

  2. Developing a Method for Resolving NOx Emission Inventory Biases Using Discrete Kalman Filter Inversion, Direct Sensitivities, and Satellite-Based Columns

    Science.gov (United States)

    An inverse method was developed to integrate satellite observations of atmospheric pollutant column concentrations and direct sensitivities predicted by a regional air quality model in order to discern biases in the emissions of the pollutant precursors.

  3. Monolithically Integrated Reconfigurable Filters for Microwave Photonic Links

    Science.gov (United States)

    Norberg, Erik J.

    For the purposes of commercial communication and military electronic warfare and radar alike, there is an increasing interest in RF systems that can handle very wide instantaneous bandwidths at high center frequencies. Optical signal processing has the capability to reduce latency, improve size, weight and power (SwAP) performance, and overcome the inherent bandwidth limitations of electronic counterparts. By rapidly pre-filtering wide bandwidth microwave signals in the optical domain, the analog-to-digital conversion (ADC) and subsequent digital signal processing (DSP) can be significantly relieved. Compared to channelizing and add/drop filters for wavelength division multiplexing (WDM) applications, the microwave filter application is much more challenging as it requires a more versatile filter, ideally with tunability in both frequency and bandwidth. In this work such a filter was developed using integrated photonics. By integrating the filter on a single InP chip, the stability required for coherent filtering is met, while the active integration platform offers a flexible filter design and higher tolerance in the coupler and fabrication specifications. Using an entirely deep etched fabrication with a single blanket regrowth, a simple fabrication with high yield is achieved. The reconfigurable filter is designed as an array of uncoupled filter stages with each filter stage reconfigurable as a filter pole or zero with arbitrary magnitude and phase. This gives rise to a flexible ffilter synthesis, much like an optical version of DSP filters. Flat-topped bandpass filters are demonstrated with frequency tunability over 30 GHz, bandwidth adjustable between 1.9 and 5.4 GHz, and stopband rejection >32 dB. In order to meet the stringent spurious-free dynamic range (SFDR) requirements of the microwave application, a novel epitaxial layer integration platform is developed. Optimized for high optical saturation power and low propagation loss, it produces semiconductor

  4. ADVANCED SECOND GENERATION CERAMIC CANDLE FILTERS

    Energy Technology Data Exchange (ETDEWEB)

    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

  5. High flow ceramic pot filters

    NARCIS (Netherlands)

    van Halem, D.; van der Laan, H.; Soppe, A. I.A.; Heijman, S.G.J.

    2017-01-01

    Ceramic pot filters are considered safe, robust and appropriate technologies, but there is a general consensus that water revenues are limited due to clogging of the ceramic element. The objective of this study was to investigate the potential of high flow ceramic pot filters to produce more

  6. Derivative free filtering using Kalmtool

    DEFF Research Database (Denmark)

    Bayramoglu, Enis; Hansen, Søren; Ravn, Ole

    2010-01-01

    In this paper we present a toolbox enabling easy evaluation and comparison of different filtering algorithms. The toolbox is called Kalmtool 4 and is a set of MATLAB tools for state estimation of nonlinear systems. The toolbox contains functions for extended Kalman filtering as well as for DD1 fi...

  7. Sample-whitened matched filters

    DEFF Research Database (Denmark)

    Andersen, Ib

    1973-01-01

    A sample-whitened matched filter (SWMF) for a channel with intersymbol interference and additive white Gaussian noise is defined as a linear filter with the properties that its output samples are a sufficient statistic for the MAP estimation of the transmitted sequence and have uncorrelated noise...

  8. Optimal search filters for renal information in EMBASE.

    Science.gov (United States)

    Iansavichus, Arthur V; Haynes, R Brian; Shariff, Salimah Z; Weir, Matthew; Wilczynski, Nancy L; McKibbon, Ann; Rehman, Faisal; Garg, Amit X

    2010-07-01

    EMBASE is a popular database used to retrieve biomedical information. Our objective was to develop and test search filters to help clinicians and researchers efficiently retrieve articles with renal information in EMBASE. We used a diagnostic test assessment framework because filters operate similarly to screening tests. We divided a sample of 5,302 articles from 39 journals into development and validation sets of articles. Information retrieval properties were assessed by treating each search filter as a "diagnostic test" or screening procedure for the detection of relevant articles. We tested the performance of 1,936,799 search filters made of unique renal terms and their combinations. REFERENCE STANDARD & OUTCOME: The reference standard was manual review of each article. We calculated the sensitivity and specificity of each filter to identify articles with renal information. The best renal filters consisted of multiple search terms, such as "renal replacement therapy," "renal," "kidney disease," and "proteinuria," and the truncated terms "kidney," "dialy," "neph," "glomerul," and "hemodial." These filters achieved peak sensitivities of 98.7% (95% CI, 97.9-99.6) and specificities of 98.5% (95% CI, 98.0-99.0). The retrieval performance of these filters remained excellent in the validation set of independent articles. The retrieval performance of any search will vary depending on the quality of all search concepts used, not just renal terms. We empirically developed and validated high-performance renal search filters for EMBASE. These filters can be programmed into the search engine or used on their own to improve the efficiency of searching.

  9. DNN Filter Bank Cepstral Coefficients for Spoofing Detection

    DEFF Research Database (Denmark)

    Yu, Hong; Tan, Zheng-Hua; Zhang, Yiming

    2017-01-01

    With the development of speech synthesis techniques, automatic speaker verification systems face the serious challenge of spoofing attack. In order to improve the reliability of speaker verification systems, we develop a new filter bank-based cepstral feature, deep neural network (DNN) filter ban...... 2015 database show that the Gaussian mixture model maximum-likelihood classifier trained by the new feature performs better than the state-of-the-art linear frequency triangle filter bank cepstral coefficients-based classifier, especially on detecting unknown attacks.......With the development of speech synthesis techniques, automatic speaker verification systems face the serious challenge of spoofing attack. In order to improve the reliability of speaker verification systems, we develop a new filter bank-based cepstral feature, deep neural network (DNN) filter bank...... cepstral coefficients, to distinguish between natural and spoofed speech. The DNN filter bank is automatically generated by training a filter bank neural network (FBNN) using natural and synthetic speech. By adding restrictions on the training rules, the learned weight matrix of FBNN is band limited...

  10. Development of filter element from nanocomposites of ultra high molar mass polyethylene having silver nanoparticles; Desenvolvimento de elemento filtrante a partir de nanocompositos de polietileno de ultra-alta massa molar contendo nanoparticulas de prata

    Energy Technology Data Exchange (ETDEWEB)

    Bizzo, Maurizio A.; Wang, S. Hui, E-mail: mbizzo@usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Escola Politecnica de Engenharia Metalurgica e de Materiais

    2015-07-01

    The production of polymer based filter elements for water is widespread in the market but has an undesirable characteristic, they are not always efficient and capable of retaining or eliminating microorganisms. This paper proposes the production of filters with biocidal activity, comprised by nanocomposites of ultra-high molar mass polyethylene (UHMMPE) containing silver nanoparticles. The polymer is responsible for the uniform porous structure of the filter element and the Ag nanoparticles for its biocidal action. The filter elements were produced from two kinds of UHMMPE particles with different particle size distributions, one in the range of 150 to 200μm and the other of 300 to 400μm. Samples were collected from the obtained filter elements and characterized by X-ray diffractometry, scanning electron microscopy and microanalysis. The results indicated the formation of nanocomposite containing silver nanoparticles. (author)

  11. A Siren Detection System based on Mechanical Resonant Filters

    Directory of Open Access Journals (Sweden)

    John N. Avaritsiotis

    2001-09-01

    Full Text Available A system based on mechanical resonant filters is proposed that can be used for the detection of acoustical signals the frequency components of which vary according to specific periodic patterns. Usually, signals of this category produced by the siren of an emergency vehicle. The device essentially implements a mechanical narrow filter bank that covers the frequency range of a typical siren sound. Signal detection is obtained by measuring the time delay between successive activation of the filters of the bank. The whole analysis reveals how a set of simple, low-cost mechanical resonant filters can replace an electronic analog or digital system for the implementation of a filter bank. Moreover, a scaling down procedure is proposed so that a microsystem may be developed.

  12. Application of RPF in MEMS gyro random drift filtering

    Science.gov (United States)

    Guowei, GAO; Yan, XIE

    2017-08-01

    With the development of micro-mechanical inertial technology, how to suppress the MEMS gyro’s random drift increasingly become a hot topic. In order to filter a certain type of MEMS gyro’s random drift, this paper introduces the regularized particle filter algorithm. The derivation of the algorithm and its application in MEMS gyro’s filtering process are described in detail in this paper: First, acquiring MEMS gyro’s static drift data and conducting data pre-treatment; then establishing the AR model by using time series analysis method, and transforming it into the corresponding state space model; finally, executing the estimation and compensation for MEMS gyro’s random drift with regular particle filter algorithm, and comparing it with other common methods in engineering. Tests and simulation results show that the regularized particle filter algorithm could achieve a good effect on the suppression of MEMS gyro’s random drift, it has a higher practical application value.

  13. Faculty Experiences of Internet Filtering at a Proprietary Higher Education Institution

    Science.gov (United States)

    Rzemyk, Thomas J.

    2011-01-01

    Despite widespread acknowledgement that Internet access in libraries and schools is filtered, the effects of that filtering on faculty who must utilize such a system for research, teaching, and curriculum development in American higher education are not known. This qualitative case study explored faculty experiences of Internet filtering in terms…

  14. Desensitized Optimal Filtering and Sensor Fusion Tool Kit Project

    Data.gov (United States)

    National Aeronautics and Space Administration — It is proposed to develop desensitized optimal filtering techniques and to implement these algorithms in a navigation and sensor fusion tool kit. These proposed...

  15. Operational Factors in Membrane Bioreactors Using a Simple Ceramic Filter

    National Research Council Canada - National Science Library

    HASAN, Md. Mahmudul; NAKAJIMA, Jun

    2014-01-01

    To explore the cost reduction of water reclamation and reuse facilities in developing countries, a simple ceramic filter made of local materials, such as clay and rice bran, was used in a membrane bioreactor (MBR) process...

  16. Turbine Engine Performance Estimation using Particle Filters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Development of a nonlinear particle filter for engine performance is proposed. The approach employs NASA high-fidelity C-MAPSS40K engine model as the central...

  17. One-Dimensional Tunable Photonic-Crystal IR Filter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — MetroLaser proposes to design and develop an innovative narrowband tunable IR filter based on the properties of a one-dimensional photonic crystal structure with a...

  18. Directional bilateral filters for smoothing fluorescence microscopy images

    Science.gov (United States)

    Venkatesh, Manasij; Mohan, Kavya; Seelamantula, Chandra Sekhar

    2015-08-01

    Images obtained through fluorescence microscopy at low numerical aperture (NA) are noisy and have poor resolution. Images of specimens such as F-actin filaments obtained using confocal or widefield fluorescence microscopes contain directional information and it is important that an image smoothing or filtering technique preserve the directionality. F-actin filaments are widely studied in pathology because the abnormalities in actin dynamics play a key role in diagnosis of cancer, cardiac diseases, vascular diseases, myofibrillar myopathies, neurological disorders, etc. We develop the directional bilateral filter as a means of filtering out the noise in the image without significantly altering the directionality of the F-actin filaments. The bilateral filter is anisotropic to start with, but we add an additional degree of anisotropy by employing an oriented domain kernel for smoothing. The orientation is locally adapted using a structure tensor and the parameters of the bilateral filter are optimized for within the framework of statistical risk minimization. We show that the directional bilateral filter has better denoising performance than the traditional Gaussian bilateral filter and other denoising techniques such as SURE-LET, non-local means, and guided image filtering at various noise levels in terms of peak signal-to-noise ratio (PSNR). We also show quantitative improvements in low NA images of F-actin filaments.

  19. Kalman Filtering with Inequality Constraints for Turbofan Engine Health Estimation

    Science.gov (United States)

    Simon, Dan; Simon, Donald L.

    2003-01-01

    Kalman filters are often used to estimate the state variables of a dynamic system. However, in the application of Kalman filters some known signal information is often either ignored or dealt with heuristically. For instance, state variable constraints (which may be based on physical considerations) are often neglected because they do not fit easily into the structure of the Kalman filter. This paper develops two analytic methods of incorporating state variable inequality constraints in the Kalman filter. The first method is a general technique of using hard constraints to enforce inequalities on the state variable estimates. The resultant filter is a combination of a standard Kalman filter and a quadratic programming problem. The second method uses soft constraints to estimate state variables that are known to vary slowly with time. (Soft constraints are constraints that are required to be approximately satisfied rather than exactly satisfied.) The incorporation of state variable constraints increases the computational effort of the filter but significantly improves its estimation accuracy. The improvement is proven theoretically and shown via simulation results. The use of the algorithm is demonstrated on a linearized simulation of a turbofan engine to estimate health parameters. The turbofan engine model contains 16 state variables, 12 measurements, and 8 component health parameters. It is shown that the new algorithms provide improved performance in this example over unconstrained Kalman filtering.

  20. Directional bilateral filters for smoothing fluorescence microscopy images

    Directory of Open Access Journals (Sweden)

    Manasij Venkatesh

    2015-08-01

    Full Text Available Images obtained through fluorescence microscopy at low numerical aperture (NA are noisy and have poor resolution. Images of specimens such as F-actin filaments obtained using confocal or widefield fluorescence microscopes contain directional information and it is important that an image smoothing or filtering technique preserve the directionality. F-actin filaments are widely studied in pathology because the abnormalities in actin dynamics play a key role in diagnosis of cancer, cardiac diseases, vascular diseases, myofibrillar myopathies, neurological disorders, etc. We develop the directional bilateral filter as a means of filtering out the noise in the image without significantly altering the directionality of the F-actin filaments. The bilateral filter is anisotropic to start with, but we add an additional degree of anisotropy by employing an oriented domain kernel for smoothing. The orientation is locally adapted using a structure tensor and the parameters of the bilateral filter are optimized for within the framework of statistical risk minimization. We show that the directional bilateral filter has better denoising performance than the traditional Gaussian bilateral filter and other denoising techniques such as SURE-LET, non-local means, and guided image filtering at various noise levels in terms of peak signal-to-noise ratio (PSNR. We also show quantitative improvements in low NA images of F-actin filaments.

  1. Selection of statistical indices in the biospeckle laser analysis regarding filtering actions

    Science.gov (United States)

    Rivera, Fernando Pujaico; Braga, Roberto Alves

    2017-07-01

    This paper tests some traditional methods to analyze dynamic laser speckle regarding their filtering actions. Additionally, we propose two new biospeckle indices based on the binary entropy, including one that avoids filtering the original signals. The work was based on theoretical developments and was validated using a drying paint monitoring test. We proved that the dynamic laser speckle, or biospeckle, is compromised by filtering actions and that it is possible to elect an index that does not provide filtering.

  2. Power Systems Development Facility. Environmental Assessment

    Energy Technology Data Exchange (ETDEWEB)

    1993-06-01

    The objective of the PSDF would be to provide a modular facility which would support the development of advanced, pilot-scale, coal-based power systems and hot gas clean-up components. These pilot-scale components would be designed to be large enough so that the results can be related and projected to commercial systems. The facility would use a modular approach to enhance the flexibility and capability for testing; consequently, overall capital and operating costs when compared with stand-alone facilities would be reduced by sharing resources common to different modules. The facility would identify and resolve technical barrier, as well as-provide a structure for long-term testing and performance assessment. It is also intended that the facility would evaluate the operational and performance characteristics of the advanced power systems with both bituminous and subbituminous coals. Five technology-based experimental modules are proposed for the PSDF: (1) an advanced gasifier module, (2) a fuel cell test module, (3) a PFBC module, (4) a combustion gas turbine module, and (5) a module comprised of five hot gas cleanup particulate control devices. The final module, the PCD, would capture coal-derived ash and particles from both the PFBC and advanced gasifier gas streams to provide for overall particulate emission control, as well as to protect the combustion turbine and the fuel cell.

  3. Effects of pre- and postnatal exposure to the UV-filter Octyl Methoxycinnamate (OMC) on the reproductive, auditory and neurological development of rat offspring

    DEFF Research Database (Denmark)

    Petersen, Marta Axelstad; Boberg, Julie; Hougaard, Karin Sørig

    2011-01-01

    development of treated offspring. Groups of 14-18 pregnant Wistar rats were dosed with 0, 500, 750 or 1000mg OMC/kg bw/day during gestation and lactation. Serum thyroxine (T(4)), testosterone, estradiol and progesterone levels were measured in dams and offspring. Anogenital distance, nipple retention......, postnatal growth and timing of sexual maturation were assessed. On postnatal day 16, gene expression in prostate and testes, and weight and histopathology of the thyroid gland, liver, adrenals, prostate, testes, epididymis and ovaries were measured. After weaning, offspring were evaluated in a battery...... less severely affected in the offspring. On postnatal day 16, high dose male offspring showed reduced relative prostate and testis weights, and a dose-dependent decrease in testosterone levels. In OMC exposed female offspring, motor activity levels were decreased, while low and high dose males showed...

  4. SU-G-BRB-07: Developing a QA Procedure for Gated VMAT SABR Treatments Using 10 MV Beam in Flattening-Filter Free Mode

    Energy Technology Data Exchange (ETDEWEB)

    Chitsazzadeh, S [University of Victoria, Victoria, British Columbia (Canada); Wells, D [British Columbia Cancer Agency, Victoria, British Columbia (Canada); Mestrovic, A [British Columbia Cancer Agency, Vancouver, British Columbia (Canada)

    2016-06-15

    Purpose: To develop a QA procedure for gated VMAT stereotactic ablative radiotherapy (SABR) treatments. Methods: An interface was constructed to attach the translational stage of a Quasar respiratory motion phantom to a pinpoint ion chamber insert and move the ion chamber inside an ArcCheck diode array. The Quasar phantom controller used a patient specific breathing pattern to translate the ion chamber in a superior-inferior direction inside the ArcCheck. An amplitude-based RPM tracking system was specified to turn the beam on during the exhale phase of the breathing pattern. SABR plans were developed using Eclipse for liver PTVs ranging in size from 3-12 cm in diameter using a 2-arc VMAT technique. Dose was measured in the middle of the penumbra region, where the high dose gradient allowed for sensitive detection of any inaccuracies in gated dose delivery. The overall fidelity of the dose distribution was confirmed using ArcCheck. The sensitivity of the gating QA procedure was investigated with respect to the following four parameters: PTV size, duration of exhale, baseline drift, and gating window size. Results: The difference between the measured dose to a point in the penumbra and the Eclipse calculated dose was under 2% for small residual motions. The QA procedure was independent of PTV size and duration of exhale. Baseline drift and gating window size, however, significantly affected the penumbral dose measurement, with differences of up to 30% compared to Eclipse. Conclusion: This study described a highly sensitive QA procedure for gated VMAT SABR treatments. The QA outcome was dependent on the gating window size and baseline drift. Analysis of additional patient breathing patterns will be required to determine a clinically relevant gating window size and an appropriate tolerance level for this procedure.

  5. Coal-fueled diesel technology development Emissions Control

    Energy Technology Data Exchange (ETDEWEB)

    Van Kleunen, W.; Kaldor, S.; Gal, E.; Mengel, M.; Arnold, M.

    1994-01-01

    GEESI Emissions Control program activity ranged from control concept testing of 10 CFM slipstream from a CWS fuel single cylinder research diesel engine to the design, installation, and operation of a full-size Emissions Control system for a full-size CWS fuel diesel engine designed for locomotive operation.Early 10 CFM slipstream testing program activity was performed to determine Emissions Characteristics and to evaluate Emissions Control concepts such a Barrier filtration, Granular bed filtration, and Cyclone particulate collection for reduction of particulate and gaseous emissions. Use of sorbent injection into the engine exhaust gas upstream of the barrier filter or use of sorbent media in the granular bed filter were found to provide reduction of exhaust gas SO{sub 2} and NO{sub x} in addition to collection of ash particulate. Emergence of the use of barrier filtration as a most practical Emissions Control concept disclosed a need to improve cleanability of the filter media in order to avoid reduction of turbocharger performance by excessive barrier filter pressure drop. The next progression of program activity, after the slipstream feasibility state, was 500 CFM cold flow testing of control system concepts. The successful completion of 500 CFM cold flow testing of the Envelope Filter led to a subsequent progression to a similar configuration Envelope Filter designed to operate at 500 CFM hot gas flow from the CWS fuel research diesel engine in the GETS engine test laboratory. This Envelope Filter included the design aspect proven by cold flow testing as well as optimization of the selection of the installed filter media.

  6. Coal-fueled diesel technology development emissions control

    Science.gov (United States)

    Vankleunen, W.; Kaldor, S.; Gal, E.; Mengel, M.; Arnold, M.

    1994-01-01

    General Electric Environmental Services, Inc. (GEESI), Emissions Control program activity ranged from control concept testing of 10 CFM slipstream from a coal-water-slurry (CWS) fuel single cylinder research diesel engine to the design, installation, and operation of a full-size emissions control system for a full-size CWS fuel diesel engine designed for locomotive operation. Early 10 CFM slipstream testing program activity was performed to determine emissions characteristics and to evaluate emissions control concepts such a barrier filtration, granular bed filtration, and cyclone particulate collection for reduction of particulate and gaseous emissions. Use of sorbent injection into the engine exhaust gas upstream of the barrier filter or use of sorbent media in the granular bed filter were found to provide reduction of exhaust gas SO2 and NO(x) in addition to collection of ash particulate. Emergence of the use of barrier filtration as a most practical emissions control concept disclosed a need to improve cleanability of the filter media in order to avoid reduction of turbocharger performance by excessive barrier filter pressure drop. The next progression of program activity, after the slipstream feasibility state, was 500 CFM cold flow testing of control system concepts. The successful completion of 500 CFM cold flow testing of the envelope filter led to a subsequent progression to a similar configuration envelope filter designed to operate at 500 CFM hot gas flow from the CWS fuel research diesel engine in the GETS engine test laboratory. This envelope filter included the design aspect proven by cold flow testing as well as optimization of the selection of the installed filter media.

  7. Transparent graphene microstrip filters for wireless communications

    Science.gov (United States)

    Wang, Jinchen; Guan, Yifei; Yu, Hua; Li, Na; Wang, Shuopei; Shen, Cheng; Dai, Zhijiang; Gan, Decheng; Yang, Rong; He, Songbai; Zhang, Guangyu

    2017-08-01

    A microstrip is an indispensable component for wireless communication circuits. With the development of 5G technology, optically transparent microstrip filters urgently need to be developed. In this work, we have theoretically and experimentally demonstrated the immense potential of graphene microstrips for transparent wireless communication circuits in the 5G era. Both wideband and dual-band transparent graphene microstrip filters have shown more than 80% optical transmissivity in the region from 250 nm to 2000 nm with good frequency responses. S and C band microwave signals can transmit along the graphene microstrip lines effectively while coupling excitations produce relatively large insertion losses. Our results show that transparent microstrips designed with high-quality graphene will largely scale down the size of the wireless devices and thus play an irreplaceable role in the 5G era.

  8. Face Recognition using Gabor Filters

    Directory of Open Access Journals (Sweden)

    Sajjad MOHSIN

    2011-01-01

    Full Text Available An Elastic Bunch Graph Map (EBGM algorithm is being proposed in this research paper that successfully implements face recognition using Gabor filters. The proposed system applies 40 different Gabor filters on an image. As aresult of which 40 images with different angles and orientation are received. Next, maximum intensity points in each filtered image are calculated and mark them as Fiducial points. The system reduces these points in accordance to distance between them. The next step is calculating the distances between the reduced points using distance formula. At last, the distances are compared with database. If match occurs, it means that the image is recognized.

  9. Pragmatic circuits signals and filters

    CERN Document Server

    Eccles, William

    2006-01-01

    Pragmatic Circuits: Signals and Filters is built around the processing of signals. Topics include spectra, a short introduction to the Fourier series, design of filters, and the properties of the Fourier transform. The focus is on signals rather than power. But the treatment is still pragmatic. For example, the author accepts the work of Butterworth and uses his results to design filters in a fairly methodical fashion. This third of three volumes finishes with a look at spectra by showing how to get a spectrum even if a signal is not periodic. The Fourier transform provides a way of dealing wi

  10. Simplified design of filter circuits

    CERN Document Server

    Lenk, John

    1999-01-01

    Simplified Design of Filter Circuits, the eighth book in this popular series, is a step-by-step guide to designing filters using off-the-shelf ICs. The book starts with the basic operating principles of filters and common applications, then moves on to describe how to design circuits by using and modifying chips available on the market today. Lenk's emphasis is on practical, simplified approaches to solving design problems.Contains practical designs using off-the-shelf ICsStraightforward, no-nonsense approachHighly illustrated with manufacturer's data sheets

  11. SU-F-T-506: Development and Commissioning of the Effective and Efficient Grid Therapy Using High Dose Rate Flattening Filter Free Beam and Multileaf Collimator

    Energy Technology Data Exchange (ETDEWEB)

    Liu, M; Wen, N; Beyer, C; Siddiqui, F; Chetty, I; Zhao, B [Henry Ford Health System, Detroit, MI (United States)

    2016-06-15

    Purpose: Treating bulky tumors with grid therapy (GT) has demonstrated high response rates. Long delivery time (∼15min), with consequent increased risk of intrafraction motion, is a major disadvantage of conventional MLC-based GT (MLC-GT). The goal of this study was to develop and commission a MLC-GT technique with similar dosimetric characteristics, but more efficient delivery. Methods: Grid plan was designed with 10X-FFF (2400MU/min) beam and MLC in a commercial treatment planning system (TPS). Grid size was 1cm by 1cm and grid-to-grid distance was 2cm. Field-in-field technique was used to flatten the dose profile at depth of 10cm. Prescription was 15Gy at 1.5cm depth. Doses were verified at depths of 1.5cm, 5cm and 10cm. Point dose was measured with a plastic scintillator detector (PSD) while the planar dose was measured with calibrated Gafchromic EBT3 films in a 20cm think, 30cmx30cm solid water phantom. The measured doses were compared to the doses calculated in the treatment planning system. Percent depth dose (PDD) within the grid was also measured using EBT3 film. Five clinical cases were planned to compare beam-on time. Results: The valley-to-peak dose ratio at the 3 depths was approximately 10–15%, which is very similar to published result. The average point dose difference between the PSD measurements and TPS calculation is 2.1±0.6%. Film dosimetry revealed good agreement between the delivered and calculated dose. The average gamma passing rates at the 3 depths were 95% (3%, 1mm). The average percent difference between the measured PDD and calculated PDD was 2.1% within the depth of 20cm. The phantom plan delivery time was 3.6 min. Average beam-on time was reduced by 66.1±5.6% for the 5 clinical cases. Conclusion: An effective and efficient GT technique was developed and commissioned for the treatment of bulky tumors using FFF beam combined with MLC and automation. The Department of Radiation Oncology at Henry Ford Health System receives research

  12. A Gaussian mixture ensemble transform filter

    OpenAIRE

    Reich, Sebastian

    2011-01-01

    We generalize the popular ensemble Kalman filter to an ensemble transform filter where the prior distribution can take the form of a Gaussian mixture or a Gaussian kernel density estimator. The design of the filter is based on a continuous formulation of the Bayesian filter analysis step. We call the new filter algorithm the ensemble Gaussian mixture filter (EGMF). The EGMF is implemented for three simple test problems (Brownian dynamics in one dimension, Langevin dynamics in two dimensions, ...

  13. Monolithic integrated switched-capacitor filters. I

    Science.gov (United States)

    Rienecker, W.

    1980-06-01

    The historical background of switched-capacitor filters is reviewed, and advanced design techniques for such filters are considered with reference to filter implementation in integrated systems. It is shown that basic equivalences between the components of time-invariant and time-variant networks make it possible to construct switched-capacitor filters that imitate classic filter types. Some examples of commercial switched-capacitor filters show the advantages of this technology.

  14. MATLAB Based Digital IIR Filter Design

    OpenAIRE

    Samarjeet Singh; Uma Sharma

    2012-01-01

    a fundamental aspect of signal processing is filtering. Filtering involves the manipulation of the spectrum of a signal by passing or blocking certain portions of the spectrum, depending on the frequency of those portions. In this paper, Digital filters are designed using frequency specifications. Matlab provides different options for digital filter design, which includes function, calls to filter algorithms and a graphical user interface called Sptool. A variety of filter design algorithms ...

  15. Removing Pathogens Using Nano-Ceramic-Fiber Filters

    Science.gov (United States)

    Tepper, Frederick; Kaledin, Leonid

    2005-01-01

    A nano-aluminum-oxide fiber of only 2 nanometers in diameter was used to develop a ceramic-fiber filter. The fibers are electropositive and, when formulated into a filter material (NanoCeram(TradeMark)), would attract electro-negative particles such as bacteria and viruses. The ability to detect and then remove viruses as well as bacteria is of concern in space cabins since they may be carried onboard by space crews. Moreover, an improved filter was desired that would polish the effluent from condensed moisture and wastewater, producing potable drinking water. A laboratory- size filter was developed that was capable of removing greater than 99.9999 percent of bacteria and virus. Such a removal was achieved at flow rates hundreds of times greater than those through ultraporous membranes that remove particles by sieving. Because the pore size of the new filter was rather large as compared to ultraporous membranes, it was found to be more resistant to clogging. Additionally, a full-size cartridge is being developed that is capable of serving a full space crew. During this ongoing effort, research demonstrated that the filter media was a very efficient adsorbent for DNA (deoxyribonucleic acid), RNA (ribonucleic acid), and endotoxins. Since the adsorption is based on the charge of the macromolecules, there is also a potential for separating proteins and other particulates on the basis of their charge differences. The separation of specific proteins is a major new thrust of biotechnology. The principal application of NanoCeram filters is based on their ability to remove viruses from water. The removal of more than 99.9999 percent of viruses was achieved by a NanoCeram polishing filter added to the effluent of an existing filtration device. NanoCeram is commercially available in laboratory-size filter discs and in the form of a syringe filter. The unique characteristic of the filter can be demonstrated by its ability to remove particulate dyes such as Metanyl yellow. Its

  16. Compact Micromachined Bandpass Filters for Infrared Planetary Spectroscopy

    Science.gov (United States)

    Brown, Ari D.; Aslam, Shahid; Chervenak, James A.; Huang, Wei-Chung; Merrell, Willie; Quijada, Manuel

    2011-01-01

    The thermal instrument strawman payload of the Jupiter Europa Orbiter on the Europa Jupiter Science Mission will map out thermal anomalies, the structure, and atmospheric conditions of Europa and Jupiter within the 7-100 micron spectral range. One key requirement for the payload is that the mass cannot exceed 3.7 kg. Consequently, a new generation of light-weight miniaturized spectrometers needs to be developed. On the path toward developing these spectrometers is development of ancillary miniaturized spectroscopic components. In this paper, we present a strategy for making radiation hard and low mass FIR band pass metal mesh filters. Our strategy involves using MEMS-based fabrication techniques, which will permit the quasi-optical filter structures to be made with micron-scale precision. This will enable us to achieve tight control over both the pass band of the filter and the micromachined silicon support structure architecture, which will facilitate integration of the filters for a variety of applications.

  17. Development of an automated water toxicity biosensor using Thiobacillus ferrooxidans for monitoring cyanides in natural water for a water filtering plant.

    Science.gov (United States)

    Okochi, Mina; Mima, Koji; Miyata, Maki; Shinozaki, Youhei; Haraguchi, Satoshi; Fujisawa, Minoru; Kaneko, Masao; Masukata, Tadashi; Matsunaga, Tadashi

    2004-09-30

    An on-line biosensor consisting of immobilized Thiobacillus ferrooxidans and an oxygen electrode was developed for automated monitoring of acute toxicity in water samples. T. ferrooxidans is an obligatory acidophilic, autotrophic bacterium and derives its energy by the oxidation of ferrous ion, elemental sulfur, and reduced sulfur compounds including metal sulfides. The assay is based on the monitoring of a current increase by addition of toxicoids, which is caused by the inhibition of bacterial respiration and decrease in oxygen consumption. Optimum cell number on the membrane was 5.0 x 10(8) cells. The steady-state current was obtained when concentration of FeSO4 was above 3.6 mM at pH 3. The sensor response of T. ferrooxidans immobilized membrane for 5.0 microM KCN was within an error of 10% for 30 membranes. A linear relationship was obtained at KCN concentration in the range of 0.5-3.0 microM in a flow-type monitoring system. Minimum detectable concentrations of KCN, Na2S, and NaN3 were 0.5, 1.2, and 0.07 microM, respectively. The monitoring system contained two biosensors and these sensors were cleaned with sulfuric acid (pH 1.5) twice a day. This treatment could remove fouling on microbial immobilized membrane by natural water and ferrous precipitation in the flow cell. This flow-type monitoring sensor was operated continuously for 5 months. Also, T. ferrooxidans immobilized membrane can be stored for one month at 4 degrees C when preserved with wet absorbent cotton under argon gas. Copyright 2004 Wiley Periodicals, Inc.

  18. A modified LLCL-filter with the reduced conducted EMI noise

    DEFF Research Database (Denmark)

    Wu, Weimin; Sun, Yunjie; Lin, Zhe

    2013-01-01

    ) and the Differential-Mode (DM) EMI noises are investigated for the LCL- and LLCL-filters based single-phase full-bridge grid-tied inverter. Based on this, a modified LLCL-filter topology is proposed to provide enough attenuation on the conducted EMI noise as well as to reduce the DC-side leakage current. The parameter...... design method of the filter is also developed. The comparative analysis and discussion on four filter cases (the conventional LCL-filter, the conventional LLCL-filter, the modified LCL-filter, and the modified LLCL-filter) are carried out and verified through simulations and experiments on a 0.5 kW, 110...

  19. Complex noise suppression using a sparse representation and 3D filtering of images

    Science.gov (United States)

    Kravchenko, V. F.; Ponomaryov, V. I.; Pustovoit, V. I.; Palacios-Enriquez, A.

    2017-08-01

    A novel method for the filtering of images corrupted by complex noise composed of randomly distributed impulses and additive Gaussian noise has been substantiated for the first time. The method consists of three main stages: the detection and filtering of pixels corrupted by impulsive noise, the subsequent image processing to suppress the additive noise based on 3D filtering and a sparse representation of signals in a basis of wavelets, and the concluding image processing procedure to clean the final image of the errors emerged at the previous stages. A physical interpretation of the filtering method under complex noise conditions is given. A filtering block diagram has been developed in accordance with the novel approach. Simulations of the novel image filtering method have shown an advantage of the proposed filtering scheme in terms of generally recognized criteria, such as the structural similarity index measure and the peak signal-to-noise ratio, and when visually comparing the filtered images.

  20. Buffers and vegetative filter strips

    Science.gov (United States)

    Matthew J. Helmers; Thomas M. Isenhart; Michael G. Dosskey; Seth M. Dabney

    2008-01-01

    This chapter describes the use of buffers and vegetative filter strips relative to water quality. In particular, we primarily discuss the herbaceous components of the following NRCS Conservation Practice Standards.