WorldWideScience

Sample records for contaminated hepa filters

  1. HEPA air filter (image)

    Science.gov (United States)

    ... pet dander and other irritating allergens from the air. Along with other methods to reduce allergens, such ... controlling the amount of allergens circulating in the air. HEPA filters can be found in most air ...

  2. DOE HEPA filter test program

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-05-01

    This standard establishes essential elements of a Department of Energy (DOE) program for testing HEPA filters to be installed in DOE nuclear facilities or used in DOE-contracted activities. A key element is the testing of HEPA filters for performance at a DOE Filter Test Facility (FTF) prior to installation. Other key elements are (1) providing for a DOE HEPA filter procurement program, and (2) verifying that HEPA filters to be installed in nuclear facilities appear on a Qualified Products List (QPL).

  3. 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.

  4. Evaluation of HEPA filter service life

    Energy Technology Data Exchange (ETDEWEB)

    Fretthold, J.K.; Stithem, A.R.

    1997-07-14

    Rocky Flats Environmental Technology Site (RFETS), has approximately 10,000 High Efficiency Particulate Air (HEPA) Filters installed in a variety of filter plenums. These ventilation/filtration plenum systems are used to control the release of airborne particulate contaminates to the environment during normal operations and potential accidents. This report summarizes the results of destructive and non-destructive tests on HEPA filters obtained from a wide variety of ages and service conditions. These tests were performed to determine an acceptable service life criteria for HEPA filters used at Rocky Flats Environmental Technology Site (RFETS). A total of 140 filters of various ages (1972 to 1996) and service history (new, aged unused, used) were tested. For the purpose of this report, filter age from manufacture date/initial test date to the current sample date was used, as opposed to the actual time a filter was installed in an operating system.

  5. Analysis of an MCU HEPA filter

    Energy Technology Data Exchange (ETDEWEB)

    Peters, T. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Fondeur, F. F. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-01-01

    A series of direct analyses on three portions (inlet, center, and outlet) of the High Efficiency Particulate Air (HEPA) filter material from the Modular Caustic-Side Solvent Extraction Unit (MCU) have been performed; this includes x-ray methods such as X-Ray Diffraction (XRD), Contained Scanning Electron Microscopy (CSEM) and X-Ray Fluorescence (XRF), as well as Fourier Transform InfraRed spectroscopy (FTIR). Additionally, two leaching studies (one with water, one with dichloromethane) have been performed on three portions (inlet, center, and outlet) of the HEPA filter material, with the leachates being analyzed by Inductively-coupled plasma emission spectroscopy (ICPES), Semi-Volatile Organic Analysis (SVOA) and gammascan. From the results of the analyses, SRNL feels that cesium-depleted solvent is being introduced into the HEPA filter. The most likely avenue for this is mechanical aerosolization of solvent, where the aerosol is then carried along an airstream into the HEPA filter. Once introduced into the HEPA filter media, the solvent wicks throughout the material, and migrates towards the outlet end. Once on the outlet end, continual drying could cause particulate flakes to exit the filter and travel farther down the airstream path.

  6. 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.

  7. Degradation of HEPA filters exposed to DMSO

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, W.; Wilson, K.; Larsen, G. [Lawrence Livermore National Laboratory, CA (United States)] [and others

    1995-02-01

    Dimethyl sulfoxide (DMSO) sprays are being used to remove the high explosive (HE) from nuclear weapons in the process of their dismantlement. A boxed 50 cmf HEPA filter with an integral prefilter was exposed to DMSO vapor and aerosols that were generated by a spray nozzle to simulate conditions expected in the HE dissolution operation. After 198 hours of operation, the pressure drop of the filter had increased form 1.15 inches to 2,85 inches, and the efficiency for 0.3 {mu}m dioctyl sebacate (DOS) aerosols decreased form 99.992% to 98.6%. Most of the DMSO aerosols had collected as a liquid pool inside the boxed HEPA. The liquid was blown out of the filter exit with 100 cmf air flow at the end of the test. Since the filter still met the minimum allowed efficiency of 99.97% after 166 hours of exposure, we recommend replacing the filter every 160 hours of operation or sooner if the pressure drop increases by 50%. Examination of the filter showed that visible cracks appeared at the joints of the wooden frame and a portion of the sealant had pulled away from the frame. Since all of the DMSO will be trapped in the first HEPA filter, the second HEPA filter should not suffer from DMSO degradation. Thus the combined efficiency for the first filter (98.6%) and the second filter (99.97%) is 99.99996% for 0.3 {mu}m particles. If the first filter is replaced prior to its degradation, each of the filters will have 99.97% efficiency, and the combined efficiency will be 99.999991%. The collection efficiency for DMSO/HE aerosols will be much higher because the particle size is much greater.

  8. Specification for HEPA filters used by DOE contractors

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-01

    This standard establishes specification and testing requirements for High Efficiency Particulate Air (HEPA) filters procured to provide personnel and environmental protection when installed in DOE nuclear facilities. The standard specifies minimum requirements to be included in contractor specifications.

  9. Test plan for N2 HEPA filters assembly shop stock used on PFP E4 exhaust system

    Energy Technology Data Exchange (ETDEWEB)

    DICK, J.D.

    1999-09-01

    At Plutonium Finishing Plant (PFP) and Plutonium Reclamation Facility (PRF) Self-contained HEPA filters, encased in wooden frames and boxes, are installed in the E4 Exhaust Ventilation System to provide confinement of radioactive releases to the environment and confinement of radioactive contamination within designated zones inside the facility. Recently during the routine testing in-leakage was discovered downstream of the Self-contained HEPA filters boxes. This Test Plan describes the approach to conduct investigation of the root causes for the in-leakage of HEPA filters.

  10. 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.

  11. Performance of HEPA filters under hot dynamic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Frankum, D.P.; Costigan, G. [AEA Technology, Oxfordshire (United Kingdom)

    1995-02-01

    Accidents in nuclear facilities involving fires may have implications upon the ventilation systems where high efficiency particulate air (HEPA) filters are used to minimise the airborne release of radioactive or toxic particles. The Filter Development Section at Harwell Laboratory has been investigating the effect of temperature on the performance of HEPA filters under hot dynamic conditions[{sub 1}] for a number of years. The test rig is capable of delivering air flows of 10001/s (at ambient conditions) at temperatures up to 500{degrees}C, where measurements of the penetration and pressure drop across the filter are obtained. This paper reports the experiments on different constructions of HEPA filters; rectangular and circular. The filters were tested at an air temperature of 200{degrees}C for up to 48 hours at the rated airflow to assess their performance. The penetration measurements for rectangular filters were observed to be below 0.021% after prolonged operation. In a number of cases, holes appeared along the pleat creases of circular filters although the penetration remained below 1%. The sealing gasket for these filters was noted to deform with temperature, permitting a leakage path. A prototype high strength circular filter was evaluated at temperatures of up to 400{degrees}C with a penetration less than 0.65%.

  12. Preliminary studies to determine the shelf life of HEPA filters

    Energy Technology Data Exchange (ETDEWEB)

    Gilbert, H.; Fretthold, J.K.; Rainer, F. [Lawrence Livermore National Laboratory, CA (United States)] [and others

    1995-02-01

    We have completed a preliminary study using filter media tests and filter qualification tests to investigate the effect of shelf-life on HEPA filter performance. Our media studies showed that the tensile strength decreased with age, but the data were not sufficient to establish a shelf-life. Thermogravimetric analyses demonstrated that one manufacturer had media with low tensile strength due to insufficient binder. The filter qualification tests (heated air and overpressure) conducted on different aged filters showed that filter age is not the primary factor affecting filter performance; materials and the construction design have a greater effect. An unexpected finding of our study was that sub-standard HEPA filters have been installed in DOE facilities despite existing regulations and filter qualification tests. We found that the filter with low tensile strength failed the overpressure test. The same filter had passed the heated air test, but left the filter so structurally weak, it was prone to blow-out. We recommend that DOE initiate a filter qualification program to prevent this occurrence.

  13. 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.

  14. A review of DOE HEPA filter component test activities

    Energy Technology Data Exchange (ETDEWEB)

    Slawski, J.W.; Bresson, J.F. [Informatics Corp., Inc., Albuquerque, NM (United States); Scripsick, R.C. [Los Alamos National Lab., NM (United States)

    1997-08-01

    All HEPA filters purchased for installation in DOE nuclear facilities are required to be tested at a Filter Test Facility (FTF) prior to installation. The number of HEPA filters purchased by DOE has been reduced so much that the Hanford FTF was closed. From Fiscal Year (FY) 1992 to 1994, funding was not provided to the FTF Technical Support Group (TSG) at the Los Alamos National Laboratory. As a consequence, Round Robin Tests (RRTs), performed twice each year by the FTFs to assess constituency of test results among the FTFs, were not performed in FY 1992 and FY 1993. The Annual Reports of FTF test activities were not prepared for FY 1992 - 1995. Technical support provided to the FTFs was minimal. There is talk of closing a second FTF, and ongoing discussions as to whether DOE will continue to fund operation of the FTFs. In FY 1994, DOE Defense Programs commenced funding the TSG. RRT data for FY 1994 and 1995 have been entered into the database; the FY 1994 RRT report has been issued; and the FY 1995 RRT report is in progress. Data from semiannual reports have been retrieved and entered into the database. Standards related to HEPA filter test and procurement activities are now scheduled for issuance by FY 1996. Continuation of these activities depends on whether DOE will continue to support the HEPA filter test program. The history and activities of the FTFs and the TSG at Los Alamos have been reported at previous Air Cleaning Conferences. Data from the FY 1991 Annual Report of FTF activities was presented at the 1992 Air Cleaning Conference. Preparation of the Annual Reports was temporarily suspended in 1992. However, all of the FTF Semiannual report data have been retrieved and entered into the data base. This paper focuses primarily on the results of HEPA filter tests conducted by FTFs during FY 1992 - FY 1995, and the possible effects of the DOE program uncertainties on the quality of HEPA filters for installation at the DOE sites. 15 refs., 13 tabs.

  15. Improved HEPA Filter Technology for Flexible and Rigid Containment Barriers

    Energy Technology Data Exchange (ETDEWEB)

    Pinson, Paul Arthur

    1998-07-01

    Safety and reliability in glovebox operations can be significantly improved and waste packaging efficiencies can be increased by inserting flexible, lightweight, high capacity HEPA filters into the walls of plastic sheet barriers. This HEPA filter/barrier technology can be adapted to a wide variety of applications: disposable waste bags, protective environmental barriers for electronic equipment, single or multiple use glovebag assemblies, flexible glovebox wall elements, and room partitions. These reliable and inexpensive filtered barriers have many uses in fields such as radioactive waste processing, HVAC filter changeout, vapor or grit blasting, asbestos cleanup, pharmaceutical, medical, biological, and electronic equipment containment. The applications can result in significant cost savings, improved operational reliability and safety, and total waste volume reduction. This technology was developed at the Argonne National Laboratory-West (ANL-W) in 1993 and has been used at ANL-W since then at the TRU Waste Characterization Chamber Gloveboxes. Another 1998 AGS Conference paper titled "TRU Waste Characterization Gloveboxes", presented by Mr. David Duncan of ANL-W, describes these boxes.

  16. Potential for HEPA filter damage from water spray systems in filter plenums

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, W. [Lawrence Livermore National Lab., CA (United States); Fretthold, J.K. [Rocky Flats Safe Sites of Colorado, Golden, CO (United States); Slawski, J.W. [Department of Energy, Germantown, MD (United States)

    1997-08-01

    The water spray systems in high efficiency particulate air (HEPA) filter plenums that are used in nearly all Department of Energy (DOE) facilities for protection against fire was designed under the assumption that the HEPA filters would not be damaged by the water sprays. The most likely scenario for filter damage involves filter plugging by the water spray, followed by the fan blowing out the filter medium. A number of controlled laboratory tests that were previously conducted in the late 1980s are reviewed in this paper to provide a technical basis for the potential HEPA filter damage by the water spray system in HEPA filter plenums. In addition to the laboratory tests, the scenario for BEPA filter damage during fires has also occurred in the field. A fire in a four-stage, BEPA filter plenum at Rocky Flats in 1980 caused the first three stages of BEPA filters to blow out of their housing and the fourth stage to severely bow. Details of this recently declassified fire are presented in this paper. Although these previous findings suggest serious potential problems exist with the current water spray system in filter plenums, additional studies are required to confirm unequivocally that DOE`s critical facilities are at risk. 22 refs., 15 figs.

  17. HEPA Filter Disposal Write-Up 10/19/16

    Energy Technology Data Exchange (ETDEWEB)

    Loll, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-20

    Process knowledge (PK) collection on HEPA filters is handled via the same process as other waste streams at LLNL. The Field technician or Characterization point of contact creates an information gathering document (IGD) in the IGD database, with input provided from the generator, and submits it for electronic approval. This document is essentially a waste generation profile, detailing the physical, chemical as well as radiological characteristics, and hazards, of a waste stream. It will typically contain a general, but sometimes detailed, description of the work processes which generated the waste. It will contain PK as well as radiological and industrial hygiene analytical swipe results, and any other analytical or other supporting knowledge related to characterization. The IGD goes through an electronic approval process to formalize the characterization and to ensure the waste has an appropriate disposal path. The waste generator is responsible for providing initial process knowledge information, and approves the IGD before it routed to chemical and radiological waste characterization professionals. This is the standard characterization process for LLNL-generated HEPA Filters.

  18. HEPA Filter Disposal Write-Up 10/19/16

    Energy Technology Data Exchange (ETDEWEB)

    Loll, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-20

    Process knowledge (PK) collection on HEPA filters, is handled via the same process as other waste streams at LLNL. The Field technician or Characterization point of contact creates an information gathering document (IGD) in the IGD database, with input provided from the generator, and submits it for electronic approval. This document is essentially a waste generation profile, detailing the physical, chemical as well as radiological characteristics, and hazards, of a waste stream. It will typically contain a general, but sometimes detailed, description of the work processes which generated the waste. It will contain PK as well as radiological, and industrial hygiene analytical swipe results, and any other analytical or other supporting knowledge related to characterization. The IGD goes through an electronic approval process to formalize the characterization and to ensure the waste has an appropriate disposal path. The waste generator is responsible for providing initial process knowledge information, and approves the IGD before it routed to chemical and radiological waste characterization professionals. This is the standard characterization process for LLNL generated HEPA Filters.

  19. Radioactive air emissions notice of construction for HEPA filtered vacuum radioactive air emission units

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R.E.

    1997-10-27

    This notice of construction (NOC) requests a categorical approval for construction and operation of certain portable high-efficiency particulate air (HEPA) filtered vacuum radionuclide airborne emission units (HVUs). Approval of this NOC application is intended to allow operation of the HVUs without prior project-specific approval. This NOC does not request replacement or supersedence of any previous agreements/approvals by the Washington State Department of Health (WDOH) for the use of vacuums on the Hanford Site. These previous agreements/approvals include the approved NOCs for the use of EuroClean HEPA vacuums at the T Plant Complex and the Kelly Decontamination System at the Plutonium-Uranium Extraction (PUREX) Plant. Also, this NOC does not replace or supersede the agreement reached regarding the use of HEPA hand-held/shop-vacuum cleaners for routine cleanup activities conducted by the Environmental Restoration Project. Routine cleanup activities are conducted during the surveillance and maintenance of inactive waste sites (Radioactive Area Remedial Action Project) and inactive facilities. HEPA hand-held/shop-vacuum cleaners are used to clean up spot surface contamination areas found during outdoor radiological field surveys, and to clean up localized radiologically contaminated material (e.g., dust, dirt, bird droppings, animal feces, liquids, insects, spider webs, etc.). This agreement, documented in the October 12, 1994 Routine Meeting Minutes, is based on routine cleanup consisting of spot cleanup of low-level contamination provided that, in each case, the source term potential would be below 0.1 millirem per year. This application is intended to request sitewide approval for the new activities, and provide an option for any facility on the site to use this approval, within the terms of this NOC. The HVUs used in accordance with this NOC will support reduction of radiological contamination at various locations on the Hanford Site. Radiation Protection Air

  20. Method for HEPA filter leak scanning with differentiating aerosol detector

    Energy Technology Data Exchange (ETDEWEB)

    Kovach, B.J.; Banks, E.M.; Wikoff, W.O. [NUCON International, Inc., Columbus, OH (United States)

    1997-08-01

    While scanning HEPA filters for leaks with {open_quotes}Off the Shelf{close_quote} aerosol detection equipment, the operator`s scanning speed is limited by the time constant and threshold sensitivity of the detector. This is based on detection of the aerosol density, where the maximum signal is achieved when the scanning probe resides over the pinhole longer than several detector time-constants. Since the differential value of the changing signal can be determined by observing only the first small fraction of the rising signal, using a differentiating amplifier will speed up the locating process. The other advantage of differentiation is that slow signal drift or zero offset will not interfere with the process of locating the leak, since they are not detected. A scanning hand-probe attachable to any NUCON{reg_sign} Aerosol Detector displaying the combination of both aerosol density and differentiated signal was designed. 3 refs., 1 fig.

  1. High Efficiency Particulate Air (HEPA) filters from polyester and polypropylene fibre nonwovens

    CSIR Research Space (South Africa)

    Boguslavsky, L

    2010-10-01

    Full Text Available In this work, High Efficiency Particulate Air (HEPA) Filters are designed to keep small harmful particles from entering a control environment or to prevent them from escaping. Nonwoven fabrics for filtration application were produced from...

  2. Safety evaluation for packaging (onsite) for the Pacific Northwest National Laboratory HEPA filter box

    Energy Technology Data Exchange (ETDEWEB)

    McCoy, J.C.

    1998-07-15

    This safety evaluation for packaging (SEP) evaluates and documents the safe onsite transport of eight high-efficiency particulate air (HEPA) filters in the Pacific Northwest National Laboratory HEPA Filter Box from the 300 Area of the Hanford Site to the Central Waste Complex and on to burial in the 200 West Area. Use of this SEP is authorized for 1 year from the date of release.

  3. Summary of meeting on disposal of LET&D HEPA filters

    Energy Technology Data Exchange (ETDEWEB)

    1991-11-21

    This report is a compilation of correspondence between Westinghouse Idaho Nuclear Company and the US EPA over a period of time from 1988 to 1992 (most from 1991-92) regarding waste management compliance with EPA regulations. Typical subjects include: compliance with satellite accumulation requirements; usage of ``Sure Shot`` containers in place of aerosol cans; notice of upcoming recyclable battery shipments; disposition of batteries; HEPA filter leach sampling and permit impacts; functional and operation requirements for the spent filter handling system; summary of meeting on disposal of LET and D HEPA filters; solvent substitution database report; and mercury vapor light analytical testing.

  4. Viral Penetration of High Efficiency Particulate Air (HEPA) Filters (PREPRINT)

    Science.gov (United States)

    2009-09-01

    unique categories: vegetative bacterial cells, 54 spores, viruses, and toxins; viruses are the primary concern in this report. Although the 55 viral...most applications the HEPA is adequate, but tolerance for viral penetration is very 71 low, and thus only a few penetrating virions may be enough to...larger particles will be 397 more likely to contain viable virions). Tryptone is reported to protect viruses from 398 desiccation during aerosolization

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

    Energy Technology Data Exchange (ETDEWEB)

    Stillo, Andrew [Camfil Farr, 1 North Corporate Drive, Riverdale, NJ 07457 (United States); Ricketts, Craig I. [New Mexico State University, Department of Engineering Technology and Surveying Engineering, P.O. Box 30001 MSC 3566, Las Cruces, NM 88003-8001 (United States)

    2013-07-01

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

  6. Software Verification and Validation Test Report for the HEPA filter Differential Pressure Fan Interlock System

    Energy Technology Data Exchange (ETDEWEB)

    ERMI, A.M.

    2000-09-05

    The HEPA Filter Differential Pressure Fan Interlock System PLC ladder logic software was tested using a Software Verification and Validation (V&V) Test Plan as required by the ''Computer Software Quality Assurance Requirements''. The purpose of his document is to report on the results of the software qualification.

  7. Criteria for calculating the efficiency of deep-pleated HEPA filters with aluminum separators during and after design basis accidents

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, W.; First, M.W.; Anderson, W.L. [Lawrence Livermore National Laboratory, CA (United States)] [and others

    1995-02-01

    We have reviewed the literature on the performance of HEPA filters under normal and abnormal conditions to establish criteria for calculating the efficiency of HEPA filters in a DOE nonreactor nuclear facility during and after a Design Basis Accident (DBA). This study is only applicable to the standard deep-pleated HEPA filter with aluminum separators as specified in ASME N509[1]. Other HEPA filter designs such as the mini-pleat and separatorless filters are not included in this study. The literature review included the performance of new filters and parameters that may cause deterioration in the filter performance such as filter age, radiation, corrosive chemicals, seismic and rough handling, high temperature, moisture, particle clogging, high air flow and pressure pulses. The deterioration of the filter efficiency depends on the exposure parameters; in severe exposure conditions the filter will be damaged and have a residual efficiency of 0%. There are large gaps and limitations in the data that introduce significant error in the estimates of HEPA filter efficiencies under DBA conditions. Because of this limitation, conservative values of filter efficiency were chosen. The estimation of the efficiency of the HEPA filters under DBA conditions involves three steps: (1) The filter pressure drop and environmental parameters are determined during and after the DBA, (2) Comparing the filter pressure drop to a set of threshold values above which the filter is damaged. There is a different threshold value for each combination of environmental parameters, and (3) Determining the filter efficiency. If the filter pressure drop is greater than the threshold value, the filter is damaged and is assigned 0% efficiency. If the pressure drop is less, then the filter is not damaged and the efficiency is determined from literature values of the efficiency at the environmental conditions.

  8. Define and Quantify the Physics of Air Flow, Pressure Drop and Aerosol Collection in Nuclear Grade HEPA Filters

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Murray E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-02-23

    Objective: Develop a set of peer-review and verified analytical methods to adjust HEPA filter performance to different flow rates, temperatures and altitudes. Experimental testing will measure HEPA filter flow rate, pressure drop and efficiency to verify the analytical approach. Nuclear facilities utilize HEPA (High Efficiency Particulate Air) filters to purify air flow for workspace ventilation. However, the ASME AG-1 technical standard (Code on Nuclear Air and Gas Treatment) does not adequately describe air flow measurement units for HEPA filter systems. Specifically, the AG-1 standard does not differentiate between volumetric air flow in ACFM (actual cubic feet per minute)compared to mass flow measured in SCFM (standard cubic feet per minute). More importantly, the AG-1 standard has an overall deficiency for using HEPA filter devices at different air flow rates, temperatures, and altitudes. Technical Approach: The collection efficiency and pressure drops of 18 different HEPA filters will be measured over a range of flow rates, temperatures and altitudes. The experimental results will be compared to analytical scoping calculations. Three manufacturers have allocated six HEPA filters each for this effort. The 18 filters will be tested at two different flow rates, two different temperatures and two different altitudes. The 36 total tests will be conducted at two different facilities: the ATI Test facilities (Baltimore MD) and the Los Alamos National Laboratory (Los Alamos NM). The Radiation Protection RP-SVS group at Los Alamos has an aerosol wind tunnel that was originally designed to evaluate small air samplers. In 2010, modifications were started to convert the wind tunnel for HEPA filter testing. (Extensive changes were necessary for the required aerosol generators, HEPA test fixtures, temperature control devices and measurement capabilities.) To this date, none of these modification activities have been funded through a specific DOE or NNSA program. This is

  9. The effect of media area on the dust holding capacity of deep pleat HEPA filters

    Energy Technology Data Exchange (ETDEWEB)

    Dyment, J. [AWE, Aldermaston (United Kingdom); Loughborough, D. [AEAT Harwell, Oxford (United Kingdom)

    1997-08-01

    The high potential cost of storage, treatment and disposal of radioactive wastes places a premium on the longevity of installed HEPA filters in situations in radioactive processing facilities where dust capacity is a life determining factor. Previous work investigated the dust holding capacity v pressure drop characteristics of different designs of HEPA filter and also the effect of using graded density papers. This paper records an investigation of the effect of media area variation on the dust holding capacity of the {open_quotes}deep-pleat{close_quotes} design of HEPA filter. As in the previously reported work two test dusts (carbon black and sub micron sodium chloride) in the range (0.15 - 0.4{mu}m) were used. Media area adjustment was effected by varying the number of separators within the range 60 - 90. Results with the coarser dust allowed an optimum media area to be identified. Media areas greater or smaller than this optimum retained less dust than the optimum for the same terminal pressure drop. Conversely with the finer sodium chloride aerosol the dust holding capacity continued to increase up to the maximum area investigated. 7 refs., 4 figs.

  10. Performance testing of HEPA filters: Progress towards a European standard procedure

    Energy Technology Data Exchange (ETDEWEB)

    Dyment, J.

    1997-08-01

    Proposals for a future European testing procedure for {open_quotes}High Efficiency Particulate Air Filters (HEPA and ULPA){close_quotes} are being developed by CEN (Comite Europeen de Normalisation). The new standard will be given the status of national standard in participating countries, conflicting national standards being withdrawn. The standard will comprise 5 parts covering the grouping and classification of HEPA and ULPA filters according to their efficiency, fundamental principles of testing, marking etc (in part 1). Part 2 will cover aerosol production, measurement principles, counting equipment and statistics. Parts 3-5 will cover testing flat sheet media, leak testing of filter elements and the efficiency testing of filter elements respectively. The efficiency test methods allow the use of either homogeneous monodisperse or polydisperse aerosols for the determination of particulate filtration efficiencies as a function of particle size. The particle size at which maximum penetration occurs is first determined in flat sheet media tests; tests on filter elements (constructed using the same filter medium) may be carried out using either a homogeneous monodisperse aerosol of the size at which maximum penetration occurs (MPPS) or a polydisperse aerosol whose median size is close to the MPPS. Tests with monodisperse aerosols may be conducted using condensation nucleus counting equipment; tests using polydisperse test aerosols require the use of optical sizing particle counters. When determining the efficiency of filter elements the downstream aerosol concentrations may be determined from air samples obtained using either an overall method (single point sampling after mixing) or a scan method. The scan method also allows {open_quotes}local{close_quotes} efficiency values to be determined. 1 ref., 1 fig., 1 tab.

  11. Institute for Clean Energy Technology Mississippi State University NSR&D Aged HEPA Filter Study Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Jacks, Robert [Mississippi State Univ., Mississippi State, MS (United States); Stormo, Julie [Mississippi State Univ., Mississippi State, MS (United States); Rose, Coralie [Mississippi State Univ., Mississippi State, MS (United States); Rickert, Jaime [Mississippi State Univ., Mississippi State, MS (United States); Waggoner, Charles A. [Mississippi State Univ., Mississippi State, MS (United States)

    2017-03-22

    Data have demonstrated that filter media lose tensile strength and the ability to resist the effects of moisture as a function of age. Testing of new and aged filters needs to be conducted to correlate reduction of physical strength of HEPA media to the ability of filters to withstand upset conditions. Appendix C of the Nuclear Air Cleaning Handbook provides the basis for DOE’s HEPA filter service life guidance. However, this appendix also points out the variability of data, and it does not correlate performance of aged filters to degradation of media due to age. Funding awarded by NSR&D to initiate full-scale testing of aged HEPA filters addresses the issue of correlating media degradation due to age with testing of new and aged HEPA filters under a generic design basis event set of conditions. This funding has accelerated the process of describing this study via: (1) establishment of a Technical Working Group of all stakeholders, (2) development and approval of a test plan, (3) development of testing and autopsy procedures, (4) acquiring an initial set of aged filters, (5) testing the initial set of aged filters, and (6) developing the filter test report content for each filter tested. This funding was very timely and has moved the project forward by at least three years. Activities have been correlated with testing conducted under DOE-EM funding for evaluating performance envelopes for AG-1 Section FC Separator and Separatorless filters. This coordination allows correlation of results from the NSR&D Aged Filter Study with results from testing new filters of the Separator and Separatorless Filter Study. DOE-EM efforts have identified approximately 100 more filters of various ages that have been stored under Level B conditions. NSR&D funded work allows a time for rigorous review among subject matter experts before moving forward with development of the testing matrix that will be used for additional filters. The NSR&D data sets are extremely valuable in as much

  12. Health hazards associated with the use of di-(2-ethylhexyl) phthalate (commonly referred to as DOP) in HEPA filter test

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-01-01

    Di-(2-ethylhexyl) phthalate (DEHP), commonly referred to as di-octyl phthalate, is an important production chemical in the US. In addition to its major use as an additive in plastics, DEHP is widely used to evaluate the effectiveness of high efficiency particulate air (HEPA) filters. Historically, DEHP was also used in quantitative fit testing for respirators. Evaluations of this compound a decade ago showed that it can induce hepatocellular carcinomas in laboratory animals. Although most Department of Energy (DOE) facilities have since discontinued using DEHP in respirator fit testing, DEHP continues to be used for evaluating HEPA filters. This report summarizes available information on the toxicity, mutagenicity, carcinogenicity, and other hazards and problems posed by DEHP, specifically with reference to HEPA filter testing. Information on work practice improvements as well as the availability and suitability of DEHP substitutes are also presented. This material should assist the DOE in the safe use of this material.

  13. The case for improved HEPA-filter mechanical performance standards revisited

    Energy Technology Data Exchange (ETDEWEB)

    Ricketts, C.I.; Smith, P.R. [New Mexico State Univ., Las Cruces, NM (United States)

    1997-08-01

    Under benign operating conditions, High Efficiency Particulate Air (HEPA) filter units serve as reliable and relatively economical components in the air cleaning systems of nuclear facilities worldwide. Despite more than four decades of filter-unit evaluation and improvements, however, the material strength characteristics of the glass fiber filter medium continue to ultimately limit filter functional reliability. In worst-case scenarios involving fire suppression, loss-of-coolant accidents (LOCA`s), or exposure to shock waves or tornado induced flows, rupture of the filter medium of units meeting current qualification standards cannot be entirely ruled out. Even under so-called normal conditions of operation, instances of filter failure reported in the literature leave open questions of filter-unit reliability. Though developments of filter units with improved burst strengths have been pursued outside the United States, support for efforts in this country has been comparatively minimal. This despite user requests for filters with greater moisture resistance, for example. Or the fact that conventional filter designs result in not only the least robust component to be found in a nuclear air cleaning system, but also the one most sensitive to the adverse effects of conditions deviating from those of normal operation. Filter qualification-test specifications of current codes, standards, and regulatory guidelines in the United States are based primarily upon research performed in a 30-year period beginning in the 1950`s. They do not seem to reflect the benefits of the more significant developments and understanding of filter failure modes and mechanisms achieved since that time. One overseas design, based on such knowledge, has proven reliability under adverse operating conditions involving combined and serial challenges. Its widespread use, however, has faltered on a lack of consensus in upgrading filter performance standards. 34 refs., 2 figs., 3 tabs.

  14. The development of a HEPA filter with improved dust holding characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Dyment, J.; Hamblin, C.

    1995-02-01

    A limitation of the HEPA filters used in the extract of nuclear facilities is their relatively low capacity for captured dust. The costs associated with the disposal of a typical filter means that there are clear incentives to extend filter life. The work described in this report are the initial stages in the development of a filter which incorporates a medium which enhances its dust holding capacity. Experimental equipment was installed to enable the dust loading characteristics of candidate media to be compared with those of the glass fibre based papers currently used in filter construction. These tests involved challenging representative samples of the media with an air stream containing a controlled concentration of thermally generated sodium chloride particles. The dust loading characteristics of the media were then compared in terms of the rate of increasing in pressure differential. A number of {open_quotes}graded density{close_quotes} papers were subsequently identified which appeared to offer significant improvements in dust holding. In the second phase of the programme deep-pleat filters (1,700 M{sup 3}h{sup {minus}1}) incorporating graded density papers were manufactured and tested. Improvements of up to 50% were observed in their capacity for the sub-micron sodium chloride test dust. Smaller differences (15%) were measured when a coarser, carbon black, challenge was used. This is attributed to the differences in the particles sizes of the two dusts.

  15. Extraction of semivolatile organic compounds from high-efficiency particulate air (HEPA) filters by supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Schilling, J.B.

    1997-09-01

    Supercritical fluid extraction (SFE) using unmodified carbon dioxide has been explored as an alternative method for the extraction of semivolatile organic compounds from high-efficiency particulate air (HEPA) filters. HEPA filters provide the final stage of containment on many exhaust systems in US Department of Energy (DOE) facilities by preventing the escape of chemical and radioactive materials entrained in the exhausted air. The efficiency of the filters is tested by the manufacturer and DOE using dioctylphthalate (DOP), a substance regulated by the US Environmental Protection Agency under the Resource Conservation and Recovery Act. Therefore, the filters must be analyzed for semivolatile organics before disposal. Ninety-eight acid, base, and neutral semivolatile organics were spiked onto blank HEPA material and extracted using SFE, Soxhlet, automated Soxhlet, and sonication techniques. The SFE conditions were optimized using a Dionex SFE-703 instrument. Average recoveries for the 98 semivolatile compounds are 82.7% for Soxhlet, 74.0% for sonication, 70.2% for SFE, and 62.9% for Soxtec. Supercritical fluid extraction reduces the extraction solvent volume to 10--15 mL, a factor of 20--30 less than Soxhlet and more than 5 times less than Soxtec and sonication. Extraction times of 30--45 min are used compared to 16--18 h for Soxhlet extraction.

  16. 生物安全实验室效率检漏型高效空气过滤装置的研制%Development of HEPA Filter Unit with Efficiency Leak Detection for Bio-safety Laboratory

    Institute of Scientific and Technical Information of China (English)

    张宗兴; 赵明; 衣颖; 祁建城

    2013-01-01

    目的:研制一种可安装在生物安全实验室内的效率检漏型排风高效过滤装置,可实现对高效空气过滤器的原位检漏和消毒.方法:依据高效空气过滤器效率法检测和气体消毒要求,进行高效空气过滤装置的结构设计.结果:该高效空气过滤装置,可采用效率法对高效过滤器进行原位检漏,并可对过滤器进行原位气体消毒及验证消毒效果,满足相关标准要求.结论:该装置适用于生物安全实验室的污染空气排放处置,可满足我国生物安全实验室建设的需要.%Objective To develop an exhaust HEPA filter unit installed in the laboratory that has the functions of in-situ leak detection and sterilization of HEPA filter.Methods The structure composition of the unit was designed according to the requirement of efficiency test and gas sterilization of HEPA filter.Results The HEPA filter unit which met relevant standard requirements had the functions of in-situ leak detection using efficiency test,sterilization and validating the effect of sterilization of HEPA filter.Conclusion The unit which is applicable to decontamination of contaminated air emissions of bio-safety laboratory can meet the needs of construction of bio-safety laboratory in China.

  17. Reduction in MRSA environmental contamination with a portable HEPA-filtration unit.

    Science.gov (United States)

    Boswell, T C; Fox, P C

    2006-05-01

    There is renewed interest in the hospital environment as a potentially important factor for cross-infection with methicillin-resistant Staphylococcus aureus (MRSA) and other nosocomial pathogens. The aim of this study was to evaluate the effectiveness of a portable high-efficiency particulate air (HEPA)-filtration unit (IQAir Cleanroom H13, Incen AG, Goldach, Switzerland) at reducing MRSA environmental surface contamination within a clinical setting. The MRSA contamination rate on horizontal surfaces was assessed with agar settle plates in ward side-rooms of three patients who were heavy MRSA dispersers. Contamination rates were measured at different air filtration rates (60-235 m(3)/h) and compared with no air filtration using Poisson regression. Without air filtration, between 80% and 100% of settle plates were positive for MRSA, with the mean number of MRSA colony-forming units (cfu)/10-h exposure/plate ranging from 4.1 to 27.7. Air filtration at a rate of 140 m(3)/h (one patient) and 235 m(3)/h (two patients), resulted in a highly significant decrease in contamination rates compared with no air filtration (adjusted rate ratios 0.037, 0.099 and 0.248, respectively; P contamination within patient isolation rooms, and this may prove to be a useful addition to existing MRSA infection control measures.

  18. ANALYSIS OF VAPORS FROM METHYLENE CHLORIDE EXTRACTS OF NUCLEAR GRADE HEPA FILTER FIBERGLASS SAMPLES

    Energy Technology Data Exchange (ETDEWEB)

    FRYE JM; ANASTOS HL; GUTIERREZ FC

    2012-06-07

    While several organic compounds were detected in the vapor samples used in the reenactment of the preparation of mounts from the extracts of nuclear grade high-efficiency particulate air filter fiberglass samples, the most significant species present in the samples were methylene chloride, phenol, phenol-d6, and 2-fluorophenol. These species were all known to be present in the extracts, but were expected to have evaporated during the preparation of the mounts, as the mounts appeared to be dry before any vapor was collected. These species were present at the following percentages of their respective occupational exposure limits: methylene chloride, 2%; phenol, 0.4%; and phenol-d6, 0.6%. However, there is no established limit for 2-fluorophenol. Several other compounds were detected at low levels for which, as in the case of 2-fluorophenol, there are no established permissible exposure limits. These compounds include 2-chlorophenol; N-nitroso-1-propanamine; 2-fluoro-1,1{prime}-biphenyl; 1,2-dihydroacenaphthylene; 2,5-cyclohexadiene-1,4-dione,2,6-bis(1,1-dimethylethyl); trimethyl oxirane; n-propylpropanamine; 2-(Propylamino)ethanol; 4-methoxy-1-butene; 6-methyl-5-hepten-2-one; and 3,4-dimethylpyridine. Some of these were among those added as surrogates or spike standards as part ofthe Advanced Technologies and Laboratories International, Inc. preparation ofthe extract of the HEPA filter media and are indicated as such in the data tables in Section 2, Results; other compounds found were not previously known to be present. The main inorganic species detected (sulfate, sodium, and sulfur) are also consistent with species added in the preparation of the methylene chloride extract of the high-efficiency particulate air sample.

  19. Phase I characterization of the HEPA (High Efficiency Particulate Air) filter media used in the airborne activity confinement system at the Savannah River Site

    Energy Technology Data Exchange (ETDEWEB)

    Novick, V.J.; Higgins, P.J. (Argonne National Lab., IL (USA))

    1989-01-01

    The purpose of this report was to characterize the HEPA filter media material. This work consisted of two major tasks. First, the pressure drop characteristics of the HEPA filter material were measured as a function of the aerosol mass loading. Particle size effects were studied by using three different particle size distributions to load the filter material. The second task was to determine the filtration efficiency spectrum for solid particles as a function of particle diameter. The filtration efficiency was measured at two different media velocities, one corresponding to the equivalent flow rate under normal operating conditions, the other corresponding to the minimum equivalent flow rate expected through the filter compartments. These tests were conducted at the Argonne National Laboratory between September 1988 and February 1989. 20 refs., 31 figs., 10 tabs.

  20. The In Situ Test of HEPA Filter in Cleanroom%洁净室高效过滤器的在位检测

    Institute of Scientific and Technical Information of China (English)

    赵厚猛

    2012-01-01

    对洁净室高效过滤器在位检测做了简单的介绍,对旧车间高效过滤器进行在位检测提供了指导意见。%The introduction to in situ test of HEPA filter in cleanroom was made, Providing guidance to such test in old workshop.

  1. Exposure Assessment of Four Pharmaceutical Powders Based on Dustiness and Evaluation of Damaged HEPA Filters

    DEFF Research Database (Denmark)

    Levin, Marcus; Koponen, Ismo K.; Jensen, Keld A.

    2014-01-01

    the penetration is still dominated by particles larger than 100nm. Whereas the exposure potential was evident, the potential dust concentrations in air ducts following the pouring scenario above were at pg/m(3) levels. Hence, filter penetration at these damage levels was assumed to be only critical, if the active...

  2. A Quasi-Experimental Study Analyzing the Effectiveness of Portable High-Efficiency Particulate Absorption Filters in Preventing Infections in Hematology Patients during Construction

    Directory of Open Access Journals (Sweden)

    Gülden Yılmaz

    2016-03-01

    Full Text Available Objective: The increased risk of infection for patients caused by construction and renovation near hematology inpatient clinics is a major concern. The use of high-efficiency particulate absorption (HEPA filters can reduce the risk of infection. However, there is no standard protocol indicating the use of HEPA filters for patients with hematological malignancies, except for those who have undergone allogeneic hematopoietic stem cell transplantation. This quasi-experimental study was designed to measure the efficacy of HEPA filters in preventing infections during construction. Materials and Methods: Portable HEPA filters were placed in the rooms of patients undergoing treatment for hematological malignancies because of large-scale construction taking place near the hematology clinic. The rates of infection during the 6 months before and after the installation of the portable HEPA filters were compared. A total of 413 patients were treated during this 1-year period. Results: There were no significant differences in the antifungal prophylaxis and treatment regimens between the groups. The rates of infections, clinically documented infections, and invasive fungal infections decreased in all of the patients following the installation of the HEPA filters. When analyzed separately, the rates of invasive fungal infections were similar before and after the installation of HEPA filters in patients who had no neutropenia or long neutropenia duration. HEPA filters were significantly protective against infection when installed in the rooms of patients with acute lymphocytic leukemia, patients who were undergoing consolidation treatment, and patients who were neutropenic for 1-14 days. Conclusion: Despite the advent of construction and the summer season, during which environmental Aspergillus contamination is more prevalent, no patient or patient subgroup experienced an increase in fungal infections following the installation of HEPA filters. The protective

  3. ALTERNATE HIGH EFFICIENCY PARTICULATE AIR (HEPA) FILTRATION SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Bruce Bishop; Robert Goldsmith; Karsten Nielsen; Phillip Paquette

    2002-08-16

    In Phase IIA of this project, CeraMem has further developed and scaled up ceramic HEPA filters that are appropriate for use on filtration of vent gas from HLW tanks at DOE sites around the country. This work included procuring recrystallized SiC monoliths, developing membrane and cement materials, and defining a manufacturing process for the production of prototype full sizes HEPA filters. CeraMem has demonstrated that prototype full size filters can be manufactured by producing 9 full size filters that passed DOP aerosol testing at the Oak Ridge Filter Test Facility. One of these filters was supplied to the Savannah River Technical Center (SRTC) for process tests using simulated HLW tank waste. SRTC has reported that the filter was regenerable (with some increase in pressure drop) and that the filter retained its HEPA retention capability. CeraMem has also developed a Regenerable HEPA Filter System (RHFS) design and acceptance test plan that was reviewed by DOE personnel. The design and acceptance test plan form the basis of the system proposal for follow-on work in Phase IIB of this project.

  4. Removal of emerging organic contaminants in a poplar vegetation filter

    NARCIS (Netherlands)

    Martínez Hernández, V.; Lealb, M.; Meffe, R.; Miguel Garcia, de Angel; Alonso-Alonso, C.; Bustamante, de I.; Lillo, J.; Martín, I.; Salas, J.J.

    2017-01-01

    Vegetation filters (VFs), a type of land application system, are a robust technology based on natural treatment mechanisms for the removal of wastewater contaminants. Their capacity to attenuate emerging organic contaminants (EOCs) has not yet been evaluated. The present study reports the results

  5. Particle Removal Efficiency of the Portable HEPA Air Cleaner in a Simulated Hospital Ward

    DEFF Research Database (Denmark)

    Qian, Hua; Li, Yuguo; Sun, Hequan

    2010-01-01

    Use of a HEPA (high efficiency particulate air) filter in a room is believed to assist in reducing the risk of transmission of infectious diseases through removing the particles or large droplets to which pathogens may be attached. Use of a portable HEPA filter(s) in hospital wards is hypothesized...... of beds in an isolation ward is insufficient. An experiment was conducted in a full scale experimental ward with a dimension of 6.7 m × 6 m × 2.7 m and 6 beds to test these hypotheses for a portable HEPA filter. The removal efficiency for different size particles was measured at different locations...

  6. Low-Rank Kalman Filtering in Subsurface Contaminant Transport Models

    KAUST Repository

    El Gharamti, Mohamad

    2010-12-01

    Understanding the geology and the hydrology of the subsurface is important to model the fluid flow and the behavior of the contaminant. It is essential to have an accurate knowledge of the movement of the contaminants in the porous media in order to track them and later extract them from the aquifer. A two-dimensional flow model is studied and then applied on a linear contaminant transport model in the same porous medium. Because of possible different sources of uncertainties, the deterministic model by itself cannot give exact estimations for the future contaminant state. Incorporating observations in the model can guide it to the true state. This is usually done using the Kalman filter (KF) when the system is linear and the extended Kalman filter (EKF) when the system is nonlinear. To overcome the high computational cost required by the KF, we use the singular evolutive Kalman filter (SEKF) and the singular evolutive extended Kalman filter (SEEKF) approximations of the KF operating with low-rank covariance matrices. The SEKF can be implemented on large dimensional contaminant problems while the usage of the KF is not possible. Experimental results show that with perfect and imperfect models, the low rank filters can provide as much accurate estimates as the full KF but at much less computational cost. Localization can help the filter analysis as long as there are enough neighborhood data to the point being analyzed. Estimating the permeabilities of the aquifer is successfully tackled using both the EKF and the SEEKF.

  7. Pilot-scale tests of HEME and HEPA dissolution process

    Energy Technology Data Exchange (ETDEWEB)

    Qureshi, Z.H.; Strege, D.K.

    1994-06-01

    A series of pilot-scale demonstration tests for the dissolution of High Efficiency Mist Eliminators (HEME`s) and High Efficiency Particulate Airfilters (HEPA) were performed on a 1/5th linear scale. These fiberglass filters are to be used in the Defense Waste Processing Facility (DWPF) to decontaminate the effluents from the off-gases generated during the feed preparation process and vitrification. When removed, these filters will be dissolved in the Decontamination Waste Treatment Tank (DWTT) using 5 wt% NaOH solution. The contaminated fiberglass is converted to an aqueous stream which will be transferred to the waste tanks. The filter metal structure will be rinsed with process water before its disposal as low-level solid waste. The pilot-scale study reported here successfully demonstrated a simple one step process using 5 wt% NaOH solution. The proposed process requires the installation of a new water spray ring with 30 nozzles. In addition to the reduced waste generated, the total process time is reduced to 48 hours only (66% saving in time). The pilot-scale tests clearly demonstrated that the dissolution process of HEMEs has two stages - chemical digestion of the filter and mechanical erosion of the digested filter. The digestion is achieved by a boiling 5 wt% caustic solutions, whereas the mechanical break down of the digested filter is successfully achieved by spraying process water on the digested filter. An alternate method of breaking down the digested filter by increased air sparging of the solution was found to be marginally successful are best. The pilot-scale tests also demonstrated that the products of dissolution are easily pumpable by a centrifugal pump.

  8. Methodology for modeling the microbial contamination of air filters.

    Directory of Open Access Journals (Sweden)

    Yun Haeng Joe

    Full Text Available In this paper, we propose a theoretical model to simulate microbial growth on contaminated air filters and entrainment of bioaerosols from the filters to an indoor environment. Air filter filtration and antimicrobial efficiencies, and effects of dust particles on these efficiencies, were evaluated. The number of bioaerosols downstream of the filter could be characterized according to three phases: initial, transitional, and stationary. In the initial phase, the number was determined by filtration efficiency, the concentration of dust particles entering the filter, and the flow rate. During the transitional phase, the number of bioaerosols gradually increased up to the stationary phase, at which point no further increase was observed. The antimicrobial efficiency and flow rate were the dominant parameters affecting the number of bioaerosols downstream of the filter in the transitional and stationary phase, respectively. It was found that the nutrient fraction of dust particles entering the filter caused a significant change in the number of bioaerosols in both the transitional and stationary phases. The proposed model would be a solution for predicting the air filter life cycle in terms of microbiological activity by simulating the microbial contamination of the filter.

  9. Numerical modeling and experimental analysis of volatile contaminant removal from vertical flow filters

    NARCIS (Netherlands)

    De Biase, C.

    2012-01-01

    Vertical flow filters (unplanted) and vertical flow constructed wetlands (planted), simple and inexpensive technologies to treat effectively volatile organic compounds (VOCs) contaminated water, consist of containers filled with granular material which is intermittently fed with contaminated water.

  10. Testing cleanable/reuseable HEPA prefilters for mixed waste incinerator air pollution control systems

    Energy Technology Data Exchange (ETDEWEB)

    Burns, D.B.; Wong, A.; Walker, B.W.; Paul, J.D. [Westinghouse Savannah River Co., Aiken, SC (United States)

    1997-08-01

    The Consolidated Incineration Facility (CIF) at the US DOE Savannah River Site is undergoing preoperational testing. The CIF is designed to treat solid and liquid RCRA hazardous and mixed wastes from site operations and clean-up activities. The technologies selected for use in the air pollution control system (APCS) were based on reviews of existing incinerators, air pollution control experience, and recommendations from consultants. This approach resulted in a facility design using experience from other operating hazardous/radioactive incinerators. In order to study the CIF APCS prior to operation, a 1/10 scale pilot facility, the Offgas Components Test Facility (OCTF), was constructed and has been in operation since late 1994. Its mission is to demonstrate the design integrity of the CIF APCS and optimize equipment/instrument performance of the full scale production facility. Operation of the pilot facility has provided long-term performance data of integrated systems and critical facility components. This has reduced facility startup problems and helped ensure compliance with facility performance requirements. Technical support programs assist in assuring all stakeholders the CIF can properly treat combustible hazardous, mixed, and low-level radioactive wastes. High Efficiency Particulate Air (HEPA) filters are used to remove hazardous and radioactive particulates from the exhaust gas strewn before being released into the atmosphere. The HEPA filter change-out frequency has been a potential issue and was the first technical issue to be studied at the OCTF. Tests were conducted to evaluate the performance of HEPA filters under different operating conditions. These tests included evaluating the impact on HEPA life of scrubber operating parameters and the type of HEPA prefilter used. This pilot-scale testing demonstrated satisfactory HEPA filter life when using cleanable metal prefilters and high flows of steam and water in the offgas scrubber. 8 figs., 2 tabs.

  11. DWPF GC FILTER ASSEMBLY SAMPLING AND ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Bannochie, C.; Imrich, K.

    2009-11-11

    On March 18, 2009 a Defense Waste Processing Facility (DWPF) GC Line Filter Assembly was received at the Savannah River National Laboratory (SRNL). This filter assembly was removed from operation following the completion of Sludge Batch 4 processing in the DWPF. Work on this sample was requested in a Technical Assistance Request. This document reports the pictures, observations, samples collected, and analytical results for the assembly. The assembly arrived at SRNL separated into its three component filters: high efficiency particulate air (HEPA)-1, HEPA-2, and a high efficiency mist evaporator (HEME). Each stage of the assembly's media was sampled and examined visually and by scanning electron microscopy (SEM). Solids built up in the filter housing following the first stage HEME, were dissolved in dilute nitric acid and analyzed by ICP-AES and the undissolved white solids were analyzed by x-ray diffraction (XRD). The vast majority of the material in each of the three stages of the DWPF GC Line Filter Assembly appears to be contaminated with a Hg compound that is {approx}59 wt% Hg on a total solids basis. The Hg species was identified by XRD analysis to contain a mixture of Hg{sub 4}(OH)(NO{sub 3}){sub 3} and Hg{sub 10}(OH){sub 4}(NO{sub 3}){sub 6}. Only in the core sample of the second stage HEPA, did this material appear to be completely covering portions of the filter media, possibly explaining the pressure drops observed by DWPF. The fact that the material migrates through the HEME filter and both HEPA filters, and that it was seen collecting on the outlet side of the HEME filter, would seem to indicate that these filters are not efficient at removing this material. Further SRAT off-gas system modeling should help determine the extent of Hg breakthrough past the Mercury Water Wash Tank (MWWT). The SRAT off-gas system has not been modeled since startup of the facility. Improvements to the efficiency of Hg stripping prior to the ammonia scrubber would seem

  12. Filtering images contaminated with pep and salt type noise with pulse-coupled neural networks

    Institute of Scientific and Technical Information of China (English)

    ZHANG Junying; LU Zhijun; SHI Lin; DONG Jiyang; SHI Meihong

    2005-01-01

    Pulse coupled neural network (PCNN) has a specific feature that the fire of one neuron can capture its adjacent neurons to fire due to their spatial proximity and intensity similarity. In this paper, it is indicated that this feature itself is a very good mechanism for image filtering when the image is damaged with pep and salt (PAS) type noise. An adaptive filtering method, in which the noisy pixels are first located and then filtered based on the output of the PCNN, is presented. The threshold function of a neuron in the PCNN is designed when it is used for filtering random PAS and extreme PAS noise contaminated image respectively. The filtered image has no distortion for noisy pixels and only less mistiness for non-noisy pixels, compared with the conventional window-based filtering method. Excellent experimental results show great effectiveness and efficiency of the proposed method, especially for heavy-noise contaminated images.

  13. Treatment of volatile organic contaminants in a vertical flow filter: Relevance of different removal processes

    NARCIS (Netherlands)

    De Biase, C.; Reger, D.; Schmidt, A.; Jechalke, S.; Reiche, N.; Martínez-Lavanchy, P.M.; Rosell, M.; Van Afferden, M.; Maier, U.; Oswald, S.E.; Thullner, M.

    2011-01-01

    Vertical flow filters and vertical flow constructed wetlands are established wastewater treatment systems and have also been proposed for the treatment of contaminated groundwater. This study investigates the removal processes of volatile organic compounds in a pilot-scale vertical flow filter. The

  14. Treatment of volatile organic contaminants in a vertical flow filter: Relevance of different removal processes

    NARCIS (Netherlands)

    De Biase, C.; Reger, D.; Schmidt, A.; Jechalke, S.; Reiche, N.; Martínez-Lavanchy, P.M.; Rosell, M.; Van Afferden, M.; Maier, U.; Oswald, S.E.; Thullner, M.

    2011-01-01

    Vertical flow filters and vertical flow constructed wetlands are established wastewater treatment systems and have also been proposed for the treatment of contaminated groundwater. This study investigates the removal processes of volatile organic compounds in a pilot-scale vertical flow filter.

  15. Standard Practice for Processing Aerospace Liquid Samples for Particulate Contamination Analysis Using Membrane Filters

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This practice covers the processing of liquids in preparation for particulate contamination analysis using membrane filters and is limited only by the liquid-to-membrane filter compatibility. 1.2 The practice covers the procedure for filtering a measured volume of liquid through a membrane filter. When this practice is used, the particulate matter will be randomly distributed on the filter surface for subsequent contamination analysis methods. 1.3 The practice describes procedures to allow handling particles in the size range between 2 and 1000 μm with minimum losses during handling. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

  16. Analyses of integrated aircraft cabin contaminant monitoring network based on Kalman consensus filter.

    Science.gov (United States)

    Wang, Rui; Li, Yanxiao; Sun, Hui; Chen, Zengqiang

    2017-07-11

    The modern civil aircrafts use air ventilation pressurized cabins subject to the limited space. In order to monitor multiple contaminants and overcome the hypersensitivity of the single sensor, the paper constructs an output correction integrated sensor configuration using sensors with different measurement theories after comparing to other two different configurations. This proposed configuration works as a node in the contaminant distributed wireless sensor monitoring network. The corresponding measurement error models of integrated sensors are also proposed by using the Kalman consensus filter to estimate states and conduct data fusion in order to regulate the single sensor measurement results. The paper develops the sufficient proof of the Kalman consensus filter stability when considering the system and the observation noises and compares the mean estimation and the mean consensus errors between Kalman consensus filter and local Kalman filter. The numerical example analyses show the effectiveness of the algorithm. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  17. Effectiveness of ceramic filters in capturing Giardia duodenalis cysts in experimentally contaminated water

    OpenAIRE

    Larissa Imaculada da Costa Sobrinho; Francine Alves da Silva Coelho; Matheus Diniz Gonçalves Coelho

    2016-01-01

    Giardia duodenalis is the main water-transmitted protozoan in developing countries. This study evaluated the effectiveness of ceramic filters in capturing G. duodenalis cysts and verified the porosity size needed to remove cysts from contaminated water. The study was conducted in the Laboratory of Parasitology at the University of Taubaté, where each filter unit was made by joining two Pet gallons, latex hose and a ceramic filter. Two porosity sizes were selected: 0.5-1.0 μm and 5-15 μm with ...

  18. Low-rank Kalman filtering for efficient state estimation of subsurface advective contaminant transport models

    KAUST Repository

    El Gharamti, Mohamad

    2012-04-01

    Accurate knowledge of the movement of contaminants in porous media is essential to track their trajectory and later extract them from the aquifer. A two-dimensional flow model is implemented and then applied on a linear contaminant transport model in the same porous medium. Because of different sources of uncertainties, this coupled model might not be able to accurately track the contaminant state. Incorporating observations through the process of data assimilation can guide the model toward the true trajectory of the system. The Kalman filter (KF), or its nonlinear invariants, can be used to tackle this problem. To overcome the prohibitive computational cost of the KF, the singular evolutive Kalman filter (SEKF) and the singular fixed Kalman filter (SFKF) are used, which are variants of the KF operating with low-rank covariance matrices. Experimental results suggest that under perfect and imperfect model setups, the low-rank filters can provide estimates as accurate as the full KF but at much lower computational effort. Low-rank filters are demonstrated to significantly reduce the computational effort of the KF to almost 3%. © 2012 American Society of Civil Engineers.

  19. Assessing clustering strategies for Gaussian mixture filtering a subsurface contaminant model

    KAUST Repository

    Liu, Bo

    2016-02-03

    An ensemble-based Gaussian mixture (GM) filtering framework is studied in this paper in term of its dependence on the choice of the clustering method to construct the GM. In this approach, a number of particles sampled from the posterior distribution are first integrated forward with the dynamical model for forecasting. A GM representation of the forecast distribution is then constructed from the forecast particles. Once an observation becomes available, the forecast GM is updated according to Bayes’ rule. This leads to (i) a Kalman filter-like update of the particles, and (ii) a Particle filter-like update of their weights, generalizing the ensemble Kalman filter update to non-Gaussian distributions. We focus on investigating the impact of the clustering strategy on the behavior of the filter. Three different clustering methods for constructing the prior GM are considered: (i) a standard kernel density estimation, (ii) clustering with a specified mixture component size, and (iii) adaptive clustering (with a variable GM size). Numerical experiments are performed using a two-dimensional reactive contaminant transport model in which the contaminant concentration and the heterogenous hydraulic conductivity fields are estimated within a confined aquifer using solute concentration data. The experimental results suggest that the performance of the GM filter is sensitive to the choice of the GM model. In particular, increasing the size of the GM does not necessarily result in improved performances. In this respect, the best results are obtained with the proposed adaptive clustering scheme.

  20. Field test of radioactive high efficiency filter and filter exchange techniques of fuel cycle examination facility

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Yong Hwa; Lee, Hyung Kwon; Chun, Young Bum; Park, Dae Gyu; Ahn, Sang Bok; Chu, Yong Sun; Kim, Eun Ka

    1997-12-01

    The development of high efficiency filter was started to protect human beings from the contamination of radioactive particles, toxic gases and bacillus, and its gradual performance increment led to the fabrication of Ultra Low Penetration Air Filter (ULPA) today. The application field of ULPA has been spread not only to the air conditioning of nuclear power facilities, semiconductor industries, life science, optics, medical care and general facilities but also to the core of ultra-precision facilities. Periodic performance test on the filters is essential to extend its life-time through effective maintenance. Especially, the bank test on HEPA filter of nuclear facilities handling radioactive materials is required for environmental safety. Nowadays, the bank test technology has been reached to the utilization of a minimized portable detecting instruments and the evaluation techniques can provide high confidence in the area of particle distribution and leakage test efficiency. (author). 16 refs., 13 tabs., 14 figs.

  1. Activated soil filters for removal of biocides from contaminated run-off and waste-waters

    DEFF Research Database (Denmark)

    Bester, Kai; Banzhaf, Stefan; Burkhardt, Michael

    2011-01-01

    Building facades can be equipped with biocides to prevent formation of algal, fungal and bacterial films. Thus run-off waters may contain these highly active compounds. In this study, the removal of several groups of biocides from contaminated waters by means of an activated soil filter was studied....... A technical scale activated vertical soil filter (biofilter) with different layers (peat, sand and gravel), was planted with reed (Phragmites australis) and used to study the removal rates and fate of hydrophilic to moderate hydrophobic (log Kow 1.8–4.4) biocides and biocide metabolites such as: Terbutryn...

  2. Effectiveness of ceramic filters in capturing Giardia duodenalis cysts in experimentally contaminated water

    Directory of Open Access Journals (Sweden)

    Larissa Imaculada da Costa Sobrinho

    2016-04-01

    Full Text Available Giardia duodenalis is the main water-transmitted protozoan in developing countries. This study evaluated the effectiveness of ceramic filters in capturing G. duodenalis cysts and verified the porosity size needed to remove cysts from contaminated water. The study was conducted in the Laboratory of Parasitology at the University of Taubaté, where each filter unit was made by joining two Pet gallons, latex hose and a ceramic filter. Two porosity sizes were selected: 0.5-1.0 μm and 5-15 μm with or without activated carbon, and the assays were run in triplicate. Approximately 60 μL (53 cysts of G. duodenalis cysts were placed in 2 liters of distilled water. After the preparation of the contaminated water, this solution was run through the filter until the completely filtered. Afterwards, the filtrate was processed according to the methodology described by De Faria (2006, in order to concentrate parasitic elements. The results were statistically evaluated using ANOVA and Tukey tests, showing that the 0.5- 1,0 μm porosity filter candles (with and without activated carbon were able to retain 100% of cysts of G. duodenalis. This is a result significantly superior to the results obtained in the control group (p<0.05. On the other hand, for the candles with porosity of 5 15 μm, total retention occurred only in candles with activated carbon. Based upon our results, it can be concluded that, in candles with both porosity sizes with activated carbon, all filters showed a satisfactory efficacy for filtration of G. duodenalis cysts.

  3. A 6-pole filter for improving the readability of muscle contaminated EEGs.

    Science.gov (United States)

    Ives, J R; Schomer, D L

    1988-05-01

    A multi-channel switched-capacitor 6-pole filter for significantly reducing the EMG artifact present during seizures recorded by long-term monitoring procedures has been implemented for routine use. This permits repeated replay of the seizures with different filter settings. All of the channels can be simultaneously dialed to any cut-off frequency (3 dB down) between 8 Hz and 70 Hz and the event replayed for filtering and write-out onto any standard EEG machine. The advantage of the 6-pole switched-capacitor filter is that it does not require a complex design with high precision RC components. The cut-off frequency is determined by the frequency of a simple clock that is used to select the same cut-off point for all 16 channels. By changing the clock frequency, the operator moves the cut-off point linearly. The dramatic improvement obtained by off-line digital filtering that was recently reported (Gotman et al. 1981) indicates that more efficient filtering of EMG contaminated seizures is diagnostically significant in selected cases. This approach is limited by the availability and expense of not only the computer's hardware but also the dedicated software. Specially designed 4-pole analog filters (Barlow 1984) are less expensive than digital filtering, but are difficult to design even at specific frequencies and do not allow for a range of frequencies. The switched-capacitor 6-pole filters have all the advantages of the above but are even more efficient in reducing EMG artifact. They also do not have any of the above disadvantages and cost only a few dollars per channel.

  4. Contamination due to memory effects in filtered vacuum arc plasma deposition systems

    CERN Document Server

    Martins, D R; Verdonck, P; Brown, I G

    2002-01-01

    Thin film synthesis by filtered vacuum arc plasma deposition is a widely used technique with a number of important emerging technological applications. A characteristic feature of the method is that during the deposition process not only is the substrate coated by the plasma, but the plasma gun itself and the magnetic field coil and/or vacuum vessel section constituting the macroparticle filter are also coated to some extent. If then the plasma gun cathode is changed to a new element, there can be a contamination of the subsequent film deposition by sputtering from various parts of the system of the previous coating species. We have experimentally explored this effect and compared our results with theoretical estimates of sputtering from the SRIM (Stopping and Range of Ions in Matter) code. We find film contamination of order 10-4 - 10-3, and the memory of the prior history of the deposition hardware can be relatively long-lasting.

  5. Device for detecting gas contamination, which can be filtered out. Vorrichtung zur Erfassung von ausfilterbaren Gaskontaminationen

    Energy Technology Data Exchange (ETDEWEB)

    Keller, M.

    1986-04-10

    A filter disc is described, which is situated on a horizontal, compact turntable, which is moved over a suction head, whose suction lips act with appropriate holes or bores of the turntable. The suction head is pressed from below against the parallel turntable by a spring with a Cardan action. The turntable is preferably turned in steps with a certain cycle time, particularly according to a program, by a certain number of places with 'phase displaced' multiple rotation of the turntable for complete use of the filter surface. Instead of a filter disc, adsorber material can be provided to collect the contamination. An arrangement with a feed period of 1 to 2 days and three detectors is used for monitoring the radioactivity.

  6. Application of an optimum filter for a neptune 10 PC linac to reduce electron contamination

    Energy Technology Data Exchange (ETDEWEB)

    Bahreyni Toosi, M.T.; Saberi, H.; Hashemian, A. [Mashhad University of Medical Sciences, Medical Physics Dep., Faculty of Medicine, Mashhad (Iran, Islamic Republic of); Salek, R. [Mashhad University of Medical Sciences, Radiotherapy and Oncology Dep., Emam Reza Hospital, Mashhad (Iran, Islamic Republic of)

    2006-07-01

    Full text of publication follows: Skin sparing is one of the most desirable characteristics of high energy photon beams. However, photons emerging from the target of linacs are contaminated with secondary electrons as a result of their interactions with air, collimators, flattening filter and any other objects in their path. This phenomenon tends to increase patients skin dose. A practical way to reduce the contribution of electron contamination is to place a sheet of medium to high Z material just after the secondary collimators. Filters of different thicknesses and atomic numbers were applied. The dose reduction effect was evaluated by direct measurement using a pinpoint 0.015 cm{sup 3} PTW 31006 chamber in a Scanditronix water phantom. For this purpose, the percent depth dose was measured at various depths ranging from 0 to 210 mm. These measurements were carried out for three field sizes of 10 10, 20 20 and 25 25 cm{sup 2}. The setup was adjusted for SSD = 100 cm. The surface dose and D20/D10 were used as the criteria to determine the optimum filter. The complete geometry of the linac, filters and water phantom were also simulated by MCNP-4C code to compute the optimum filter. The results show a good agreement between the experimental and calculated data. A 0.4 mm thick lead foil produces the optimum condition. For open beams, the utilization of the optimum filter resulted in a 5.7, 7.9 and 9.6% reduction in PDD of 10 10, 20 20 and 25 25 cm{sup 2} respectively without any significant change in the quality of the x-ray beam. The flatness and homogeneity of the cross-line dose profile did not show significant changes at the 10 cm and the depth of maximum dose. (authors)

  7. Glass fiber contamination of cigarette filters: an additional health risk to the smoker?

    Science.gov (United States)

    Pauly, J L; Lee, H J; Hurley, E L; Cummings, K M; Lesses, J D; Streck, R J

    1998-11-01

    We report here the results of studies documenting the contamination of a cigarette-appearing smoking article labeled Eclipse with glass fibers, fragments, and particles. Eclipse, a product of the R. J. Reynolds Tobacco Company (RJR), was commercialized in June of 1996. Eclipse is unlike conventional cigarettes in that, like its predecessor Premier, it is designed to heat and not burn tobacco. The purpose of Eclipse was to simplify the chemical composition and reduce the biological activity of the mainstream and sidestream smoke and to achieve a significant reduction of environmental tobacco smoke. In Eclipse, tobacco pyrolysis is reduced by a carbon fuel rod that serves as a heat source for generating an aerosol having nicotine and tobacco flavor. The carbon rod, at the tip of the cigarette, is insulated and bound with two wrapping mats of glass fibers. Recently, Eclipse has been modified to address consumer complaints of burdensome draw and off-taste. The redesigned Eclipse, which we have termed the NEW Eclipse, has an unconventional filter-appearing mouthpiece that consists of a cellulose acetate cylindrical bundle with a central hollow tunnel. In our analysis of Eclipse, glass fibers (length:width aspect ratio, > or = 3:1) were: (a) observed protruding from the tip; (b) identified on the white cigarette wrapping paper; (c) viewed on the surface of the cork-appearing tipping paper; (d) found in the pack residue; (e) discovered lying freely on the cut surface of the filter by both light and electron microscopy; (f) harvested from the filter with adhesive tape; and (g) displaced when Eclipse was smoked mechanically. In a study of Eclipse that had not been removed from carefully opened packs, we observed that > or = 95% of the filters were contaminated with glass fibers (Eclipse: Regular, n = 114/120, 95%; Milds, n = 118/120, 98%; Menthol, n = 120/120, 100%). Likewise, 99% of NEW Eclipse had glass fibers on the redesigned filter (Regular, n = 119/120). In contrast

  8. Contextualizing Hepatocyte Functionality of Cryopreserved HepaRG Cell Cultures.

    Science.gov (United States)

    Jackson, Jonathan P; Li, Linhou; Chamberlain, Erica D; Wang, Hongbing; Ferguson, Stephen S

    2016-09-01

    Over the last decade HepaRG cells have emerged as a promising alternative to primary human hepatocytes (PHH) and have been featured in over 300 research publications. Most of these reports employed freshly differentiated HepaRG cells that require time-consuming culture (∼28 days) for full differentiation. Recently, a cryopreserved, predifferentiated format of HepaRG cells (termed here "cryo-HepaRG") has emerged as a new model that improves global availability and experimental flexibility; however, it is largely unknown whether HepaRG cells in this format fully retain their hepatic characteristics. Therefore, we systematically investigated the hepatocyte functionality of cryo-HepaRG cultures in context with the range of interindividual variation observed with PHH in both sandwich-culture and suspension formats. These evaluations uncovered a novel adaptation period for the cryo-HepaRG format and demonstrated the impact of extracellular matrix on cryo-HepaRG functionality. Pharmacologically important drug-metabolizing alleles were genotyped in HepaRG cells and poor metabolizer alleles for CYP2D6, CYP2C9, and CYP3A5 were identified and consistent with higher frequency alleles found in individuals of Caucasian decent. We observed liver enzyme inducibility with aryl hydrocarbon receptor, constitutive androstane receptor (CAR), and pregnane X receptor activators comparable to that of sandwich-cultured PHH. Finally, we show for the first time that cryo-HepaRG supports proper CAR cytosolic sequestration and translocation to hepatocyte nuclei in response to phenobarbital treatment. Taken together, these data reveal important considerations for the use of this cell model and demonstrate that cryo-HepaRG are suitable for metabolism and toxicology screening.

  9. A randomised controlled pilot study to compare filtration factor of a novel non-fit-tested high-efficiency particulate air (HEPA) filtering facemask with a fit-tested N95 mask.

    Science.gov (United States)

    Au, S S W; Gomersall, C D; Leung, P; Li, P T Y

    2010-09-01

    Use of a fit-tested N95 or FFP2 mask is recommended to protect against transmission of airborne pathogens. This poses considerable logistic problems when preparing for, or dealing with, an epidemic. Some of these problems might be overcome by use of a compact reusable high-efficiency particulate air filtering mask that can be cut to size. We carried out a randomised controlled cross-over study to compare the efficacy of such a mask (Totobobo, Dream Lab One Pte Ltd, Singapore) with fit-tested N95 masks (1860 or 1860s or 1862; 3M, St Paul, MN, USA) in 22 healthy volunteers. The median (interquartile range) reduction in airborne particle counts was significantly higher [193-fold (145-200)] for N95 masks than for Totobobo masks [135-fold (83-184)] (P or =100-fold between N95 (19/22) and Totobobo (16/22) masks. We conclude that use of the Totobobo mask without fit testing cannot be recommended, but its performance is sufficiently promising to warrant further investigation.

  10. A HYBRID FILTER AND WRAPPER FEATURE SELECTION APPROACH FOR DETECTING CONTAMINATION IN DRINKING WATER MANAGEMENT SYSTEM

    Directory of Open Access Journals (Sweden)

    S. VISALAKSHI

    2017-07-01

    Full Text Available Feature selection is an important task in predictive models which helps to identify the irrelevant features in the high - dimensional dataset. In this case of water contamination detection dataset, the standard wrapper algorithm alone cannot be applied because of the complexity. To overcome this computational complexity problem and making it lighter, filter-wrapper based algorithm has been proposed. In this work, reducing the feature space is a significant component of water contamination. The main findings are as follows: (1 The main goal is speeding up the feature selection process, so the proposed filter - based feature pre-selection is applied and guarantees that useful data are improbable to be detached in the initial stage which discussed briefly in this paper. (2 The resulting features are again filtered by using the Genetic Algorithm coded with Support Vector Machine method, where it facilitates to nutshell the subset of features with high accuracy and decreases the expense. Experimental results show that the proposed methods trim down redundant features effectively and achieved better classification accuracy.

  11. In situ bioremediation of trichloroethylene-contaminated water by a resting-cell methanotrophic microbial filter

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, R T; Duba, A G; Durham, W B; Hanna, M L; Jackson, K J; Jovanovich, M C; Knapp, R B; Knezovich, J P; Shah, N N; Shonnard, D R; Wijesinghe, A M

    1992-10-01

    The Lawrence Livermore National Laboratory is testing and developing an in situ microbial filter technology for remediating migrating subsurface plumes contaminated with low concentrations of trichloroethylene (TCE). Their current focus is the establishment of a replenishable bioactive zone (catalytic filter) along expanding plume boundaries by the Injection of a representative methanotrophic bacterium, Methylosinus trichosporium OB3b. We have successfully demonstrated this microbial filter strategy using emplaced, attached resting cells (no methane additions) in a 1.1-m flow-through test bed loaded with water-saturated sand. Two separate 24 h pulses of TCE (109 ppb and 85 ppb), one week apart, were pumped through the system at a flow velocity of 1.5 cm/h; no TCE (<0.5 ppb) was detected on the downstream side of the microbial filter. Subsequent excavation of the wet sand confirmed the existence of a TCE-bioactive zone 19 days after it had been created. An enhanced longevity of the cellular, soluble-form methane monooxygenase produced by this methanotroph Is a result of our laboratory bioreactor culturing conditions. Additional experiments with cells in sealed vials and emplaced in the 1.1-m test bed yielded a high resting-cell finite TCE biotransformation capacity of [approximately] 0.25 mg per mg of bacteria; this is suitable for a planned sand-filled trench field demonstration at a Lawrence Livermore National Laboratory site.

  12. Evaluation of sampling methods for Bacillus spore-contaminated HVAC filters.

    Science.gov (United States)

    Calfee, M Worth; Rose, Laura J; Tufts, Jenia; Morse, Stephen; Clayton, Matt; Touati, Abderrahmane; Griffin-Gatchalian, Nicole; Slone, Christina; McSweeney, Neal

    2014-01-01

    The objective of this study was to compare an extraction-based sampling method to two vacuum-based sampling methods (vacuum sock and 37mm cassette filter) with regards to their ability to recover Bacillus atrophaeus spores (surrogate for Bacillus anthracis) from pleated heating, ventilation, and air conditioning (HVAC) filters that are typically found in commercial and residential buildings. Electrostatic and mechanical HVAC filters were tested, both without and after loading with dust to 50% of their total holding capacity. The results were analyzed by one-way ANOVA across material types, presence or absence of dust, and sampling device. The extraction method gave higher relative recoveries than the two vacuum methods evaluated (p≤0.001). On average, recoveries obtained by the vacuum methods were about 30% of those achieved by the extraction method. Relative recoveries between the two vacuum methods were not significantly different (p>0.05). Although extraction methods yielded higher recoveries than vacuum methods, either HVAC filter sampling approach may provide a rapid and inexpensive mechanism for understanding the extent of contamination following a wide-area biological release incident.

  13. Enhanced Stormwater Contaminant Removal and Improved Runoff Quality Using Modified Sorbents in Tree Filters

    Science.gov (United States)

    Schifman, L. A.; Kasaraneni, V.; Boving, T. B.; Oyanedel-Craver, V.

    2013-12-01

    Stormwater runoff, particularly in urban areas, contains high concentrations of pathogens that are often cited as one of the main reasons for beach closings and other water quality issues in coastal areas. Commonly found contaminants in runoff are often addressed by structural best management practices (BMP) that capture and treat the runoff before discharging it. Many BMP, such as tree filters, act as primary filtration devices that attenuate total suspended solids, nutrients, and heavy metals from runoff, but typically these BMPs are not designed to treat bacteria and have only minor petroleum hydrocarbon (PH) treatment capabilities. To address this shortcoming, the contaminant retention of an alternative sorption material was compared to expanded shale that is usually used in tree filters. Red cedar wood chips were modified with either Quaternary Ammonium Silane (QAS) or Silver Nanoparticles (AgNPs) to provide antimicrobial properties to the matrix and/or exploit their affinity to sorb PH, particularly polycyclic aromatic hydrocarbons (PAH). Results show that the wood chips exhibit the highest sorption capacity for QAS, making this material favorable for treating bacteria, while at the same time attenuating PAH by sorption processes. In the case of AgNP amendment to wood, less AgNP uptake and more desorption from the wood matrix was observed, making this amendment less favorable for bacteria deactivation. Batch experiments show that wood chips modified with QAS can remove up to 3 orders of magnitude of bacteria and retain up to 0.1 mg/g of PAH compared to shale, which has very limited bacteria deactivation (less than one order of magnitude) a PAH retention capacity of 0.04 mg/g. In this talk, the contaminant removal efficiency of the modified and unmodified materials will be discussed on the background of how these materials may find use in enhanced treatment of stormwater in tree filter BMPs.

  14. Evaluation of genotoxicity using automated detection of γH2AX in metabolically competent HepaRG cells.

    Science.gov (United States)

    Quesnot, Nicolas; Rondel, Karine; Audebert, Marc; Martinais, Sophie; Glaise, Denise; Morel, Fabrice; Loyer, Pascal; Robin, Marie-Anne

    2016-01-01

    The in situ detection of γH2AX was recently reported to be a promising biomarker of genotoxicity. In addition, the human HepaRG hepatoma cells appear to be relevant for investigating hepatic genotoxicity since they express most of drug metabolizing enzymes and a wild type p53. The aim of this study was to determine whether the automated in situ detection of γH2AX positive HepaRG cells could be relevant for evaluation of genotoxicity after single or long-term repeated in vitro exposure compared to micronucleus assay. Metabolically competent HepaRG cells were treated daily with environmental contaminants and genotoxicity was evaluated after 1, 7 and 14 days. Using these cells, we confirmed the genotoxicity of aflatoxin B1 and benzo(a)pyrene and demonstrated that dimethylbenzanthracene, fipronil and endosulfan previously found genotoxic with comet or micronucleus assays also induced γH2AX phosphorylation. Furthermore, we showed that fluoranthene and bisphenol A induced γH2AX while no effect had been previously reported in HepG2 cells. In addition, induction of γH2AX was observed with some compounds only after 7 days, highlighting the importance of studying long-term effects of low doses of contaminants. Together, our data demonstrate that automated γH2AX detection in metabolically competent HepaRG cells is a suitable high-through put genotoxicity screening assay.

  15. Study on the Metal Fiber Filter Modeling for Capturing Radioactive Aerosol

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seunguk; Lee, Chanhyun; Park, Minchan; Lee, Jaekeun [EcoEnergy Research Institute, Busan (Korea, Republic of)

    2015-05-15

    The components of air cleaning system are demisters to remove entrained moisture, pre-filters to remove the bulk of the particulate matter, high efficiency particulate air (HEPA) filters, iodine absorbers(generally, activated carbon) and HEPA filters after the absorbers for redundancy and collection of carbon fines. The HEPA filters are most important components to prevent radioactive aerosols from being released to control room and adjacent environment. The Conventional HEPA filter has pleated media for low pressure drop. Consequently, the filters must provide high collection efficiency as well as low pressure drop. Unfortunately, conventional HEPA filters are made of glass fiber and polyester, and pose disposal issues since they cannot be recycled. In fact, 31,055 HEPA filters used in nuclear facilities in the U.S are annually disposed. The Analyses at face velocities 1cm/s and 10cm/s are also carried out, and they also show R2 value of 0.995. However, since official HEPA filter standards are established at face velocity of 5cm/s, this value will be used in further analysis. From the comparative studies carried out at different filter thickness and face velocities, a good correlation is found between the model and the experiment.

  16. An ultrasensitive bio-surrogate for nanoporous filter membrane performance metrology directed towards contamination control in microlithography applications

    Science.gov (United States)

    Ahmad, Farhan; Mish, Barbara; Qiu, Jian; Singh, Amarnauth; Varanasi, Rao; Bedford, Eilidh; Smith, Martin

    2016-03-01

    Contamination tolerances in semiconductor manufacturing processes have changed dramatically in the past two decades, reaching below 20 nm according to the guidelines of the International Technology Roadmap for Semiconductors. The move to narrower line widths drives the need for innovative filtration technologies that can achieve higher particle/contaminant removal performance resulting in cleaner process fluids. Nanoporous filter membrane metrology tools that have been the workhorse over the past decade are also now reaching limits. For example, nanoparticle (NP) challenge testing is commonly applied for assessing particle retention performance of filter membranes. Factors such as high NP size dispersity, low NP detection sensitivity, and high NP particle-filter affinity impose challenges in characterizing the next generation of nanoporous filter membranes. We report a novel bio-surrogate, 5 nm DNA-dendrimer conjugate for evaluating particle retention performance of nanoporous filter membranes. A technique capable of single molecule detection is employed to detect sparse concentration of conjugate in filter permeate, providing >1000- fold higher detection sensitivity than any existing 5 nm-sized particle enumeration technique. This bio-surrogate also offers narrow size distribution, high stability and chemical tunability. This bio-surrogate can discriminate various sub-15 nm pore-rated nanoporous filter membranes based on their particle retention performance. Due to high bio-surrogate detection sensitivity, a lower challenge concentration of bio-surrogate (as compared to other NPs of this size) can be used for filter testing, providing a better representation of customer applications. This new method should provide better understanding of the next generation filter membranes for removing defect-causing contaminants from lithography processes.

  17. Application of air ions for bacterial de-colonization in air filters contaminated by aerosolized bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yang Seon, E-mail: rup2r@yonsei.ac.kr [School of Mechanical Engineering, Yonsei University, 262 Seongsanno, Seodaemun-Gu, Seoul, 120-749 (Korea, Republic of); Yoon, Ki Young, E-mail: yky810921@yonsei.ac.kr [Exhaust Emission Engineering Team, Hyundai Motor Company, Hwaseong 445-706, Republic of Korea (Korea, Republic of); Park, Jae Hong, E-mail: cheap@yonsei.ac.kr [School of Mechanical Engineering, Yonsei University, 262 Seongsanno, Seodaemun-Gu, Seoul, 120-749 (Korea, Republic of); Hwang, Jungho, E-mail: hwangjh@yonsei.ac.kr [School of Mechanical Engineering, Yonsei University, 262 Seongsanno, Seodaemun-Gu, Seoul, 120-749 (Korea, Republic of)

    2011-01-15

    We aerosolized the Escherichia coli (E. coli) and Staphylococcus epidermidis (S. epidermidis) bacteria and collected them on membrane filters. Then we generated air ions by applying a high voltage to a carbon fiber tip and applied them to the contaminated filters. The antibacterial efficiency was not significantly affected by the bacteria being Gram-positive or Gram-negative, however, negative ions showed a lower antibacterial efficiency than positive ions to both E. coli and S. epidermidis, even though the concentration of negative air ions was much higher than that of positive air ions. With a field emission scanning electron microscope (FE-SEM) images and fluorescence microscopy images using a LIVE/DEAD BacLight Bacterial Viability Kit, electrostatic disruption of the bacteria was found to be the dominant antibacterial effect. - Research Highlights: {yields}This study examined the effects of air ions generated by a carbon fiber ionizer on the inactivation of bioaerosols. {yields}When the ion exposure time and the ion generation concentration were increased, the antibacterial efficiency increased. {yields}The bioaerosols carried a significant number of negative electrical charges. {yields}Negative ions showed lower antibacterial efficiency than positive ions to both E. coli and S. epidermidis, even though the concentration of negative air ions was much higher than that of positive air ions.

  18. Indoor Air Contaminant Adsorption By Palm Shell Activated Carbon Filter – A Proposed Study

    Directory of Open Access Journals (Sweden)

    Leman A.M

    2016-01-01

    Full Text Available Indoor air contaminant is a public issue. High Volatile Organic Compound (VOC, Carbon monoxide (CO, Carbon dioxide (CO2, and particulate matter is becoming main issue that needs to solve. Therefore, this study focus on improving indoor air quality by using activated carbon (AC for Ventilation and Air-Conditioning (VAC. It investigated because AC is widely explored but developing AC as a filter for VAC is not developed yet. The AC prepared by physical and chemical activation process and combination both of process and it was activated by H3PO4 and NaOH. Characterization and analysis process are consists of water content, ash content, bulk density, adsorption capacity, iodine number and indoor air filtering analysis. Treated activated carbon potential in achieving higher surface area of the structure to the range of 950 to 1150 m2/g for gas phase application. The higher surface area will adsorb more air pollution. Maintained properties of activated carbon such as hardness, density, pore, extractable ash, particle size (12 by 40 mesh and pH are becoming the main concern in achieving high quality of activated carbon.

  19. Activated soil filters for removal of biocides from contaminated run-off and waste-waters.

    Science.gov (United States)

    Bester, Kai; Banzhaf, Stefan; Burkhardt, Michael; Janzen, Niklas; Niederstrasser, Bernd; Scheytt, Traugott

    2011-11-01

    Building facades can be equipped with biocides to prevent formation of algal, fungal and bacterial films. Thus run-off waters may contain these highly active compounds. In this study, the removal of several groups of biocides from contaminated waters by means of an activated soil filter was studied. A technical scale activated vertical soil filter (biofilter) with different layers (peat, sand and gravel), was planted with reed (Phragmites australis) and used to study the removal rates and fate of hydrophilic to moderate hydrophobic (log K(ow) 1.8-4.4) biocides and biocide metabolites such as: Terbutryn, Cybutryn (Irgarol® 1051), Descyclopropyl-Cybutryn (Cybutryn and Terbutryn metabolite), Isoproturon, Diuron, and its metabolite Diuron-desmonomethyl, Benzo-isothiazolinone, n-Octyl-isothiazolinone, Dichloro-n-octylisothiazolinone and Iodocarbamate (Iodocarb). Three experiments were performed: the first one (36 d) under low flow conditions (61 L m(-2) d(-1)) reached removal rates between 82% and 100%. The second one was performed to study high flow conditions: During this experiment, water was added as a pulse to the filter system with a hydraulic load of 255 L m(-2) within 5 min (retention time waters or infiltration into soil without appropriate removal. In the last experiment the removal efficiencies of the different layers were studied. Though the peat layer was responsible for most of the removal, the sand and gravel layers also contributed significantly for some compounds. All compounds are rather removed by degradation than by sorption. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. [Prevention of contamination with a heat-and-moisture-exchanger (HME) and bacterial filter during clinical anesthesia].

    Science.gov (United States)

    Shibata, M; Asano, M

    1998-12-01

    Although the use of HME and bacterial filter is a common practice to protect the anesthesia machine as well as the patients from bacterial contaminants, there is no report demonstrating the effectiveness of this filter in clinical anesthesia setting. We evaluated the actual effectiveness of the filter during clinical use. While the anesthesia breathing circuit, two bacterial filters (BB 50 T, Nihon PALL) and anesthesia bag, which were sterilized with ethylen oxide gas (EOG), were connected to the anesthesia machine and used continuously for one week, EOG sterilized HME and bacterial filter (BB 25 A, Nihon PALL) were changed before each anesthesia. Culture samples were taken from the BB 25 A, the breathing circuit and the machine side of the BB 50 T. Of the 117 BB 25 A samples taken, 6 were positive for Micrococcus, alpha-Streptococcus, Bacillus, and Staphylococcus epidermidis. From 21 breathing circuit "internal" samples, one was positive for Bacillus, Staphylococcus epidermidis. But the contamination from outside sources was suspected, since all the BB 25 as used with this circuit were negative. Use of BB 25 A prevents contamination of the breathing circuit for a period of one week. If we use BB 25 A in every anesthesia case, the changing of the breathing circuit is unnecessary, reducing the cost and simplifying procedures during clinical practice.

  1. An Iterative Ensemble Kalman Filter with One-Step-Ahead Smoothing for State-Parameters Estimation of Contaminant Transport Models

    KAUST Repository

    Gharamti, M. E.

    2015-05-11

    The ensemble Kalman filter (EnKF) is a popular method for state-parameters estimation of subsurface flow and transport models based on field measurements. The common filtering procedure is to directly update the state and parameters as one single vector, which is known as the Joint-EnKF. In this study, we follow the one-step-ahead smoothing formulation of the filtering problem, to derive a new joint-based EnKF which involves a smoothing step of the state between two successive analysis steps. The new state-parameters estimation scheme is derived in a consistent Bayesian filtering framework and results in separate update steps for the state and the parameters. This new algorithm bears strong resemblance with the Dual-EnKF, but unlike the latter which first propagates the state with the model then updates it with the new observation, the proposed scheme starts by an update step, followed by a model integration step. We exploit this new formulation of the joint filtering problem and propose an efficient model-integration-free iterative procedure on the update step of the parameters only for further improved performances. Numerical experiments are conducted with a two-dimensional synthetic subsurface transport model simulating the migration of a contaminant plume in a heterogenous aquifer domain. Contaminant concentration data are assimilated to estimate both the contaminant state and the hydraulic conductivity field. Assimilation runs are performed under imperfect modeling conditions and various observational scenarios. Simulation results suggest that the proposed scheme efficiently recovers both the contaminant state and the aquifer conductivity, providing more accurate estimates than the standard Joint and Dual EnKFs in all tested scenarios. Iterating on the update step of the new scheme further enhances the proposed filter’s behavior. In term of computational cost, the new Joint-EnKF is almost equivalent to that of the Dual-EnKF, but requires twice more model

  2. Loading and unloading of freeze-dryers: airborne contamination risks for aseptically manufactured sterile drug products.

    Science.gov (United States)

    Ljungqvist, Bengt; Reinmüller, Berit

    2007-01-01

    In pharmaceutical manufacturing, freeze-drying processes can be adversely affected by temperature differences relative to the surrounding air. Loading and unloading of freeze-dryers are performed either without or with temperature differences between the cleanroom and the chamber of the freeze-dryer. This operation can cause a flow of room air through the opening, creating a contamination risk, especially when manual handling of material is performed in this area. To minimize this risk, a high-efficiency particulate air (HEPA) filter unit should be installed above the opening to provide clean air and protect the opening. Here the theoretical relationships are discussed and design criteria are presented.

  3. Evaluation of a new filtering medium for in situ biofiltration of groundwater contaminated with BTEX compounds

    Energy Technology Data Exchange (ETDEWEB)

    Forget, D.; Deschenes, L.; Karamanev, D.; Samson, R. [Ecole Polytechnique, Montreal, PQ (Canada)

    1997-12-31

    A study was conducted in which granular peat moss (GPM) was used as an in-situ filtering medium for the remediation of BTEX (benzene, toluene, ethylbenzene, and xylene) contaminated groundwater. GPM has excellent microbiological and mechanical properties. Porosity was evaluated at 80.8 per cent, hydraulic conductivity at 1.23 x 10{sup -2} cm/s. Toluene and benzene were used in microcosm studies which were performed under aerobic and denitrifying conditions. Synthetic groundwater was used in all experiments. The indigenous microflora of GPM had the ability to degrade the pollutants after a short adaptation period. The biofilter operated under plug flow regime with intermediate axial dispersion without dead zones or preferential flow paths. The biofilter operated under stable conditions for five months with an average toluene concentration of 400 micrograms/litre at the entrance and a concentration below the detection limit at the exit without showing any signs of clogging. Scale-up of the system and on site application is being prepared. 8 refs., 11 figs.

  4. Evaluation of the Hydrophobic Grid Membrane Filter for the Enumeration of Moulds and Yeasts in Naturally-Contaminated Foods

    OpenAIRE

    V.H. Tournas

    2009-01-01

    Over 240 food samples from six food groups (tree nuts, grains and grain products, dried fruits, fresh produce, fruit juice, and dairy products) were tested for levels of fungal contamination using the NEO-GRID hydrophobic grid membrane filter (HGMF) and the FDA official (BAM) method. Results showed that HGMF performed very well for all tested commodities giving yeast and mould (YM) counts similar to those of the BAM (reference) method. Statistical analysis of the data (t-test) revealed no sig...

  5. Heterogeneity of Rapid Sand Filters and Its Effect on Contaminant Transport and Nitrification Performance

    DEFF Research Database (Denmark)

    Lopato, Laure Rose; Galaj, Zofia; Delpont, Sébastien

    2011-01-01

    dispersivity of more than 33% in the 116 h after the start of filtration with a constant pore-water velocity and a zero-order nitrification rate of 9 mgN=L=h. The full-scale experiments showed that the rapid sand filter was heterogeneous with pore-water velocities ranging from 2.2 to 3:3 m=h for the same inlet...... flow. A first-order nitrification reaction with spatially variable pore-water velocity could be interpreted as a zero-order reaction with a constant pore-water velocity. A model demonstrated that filter heterogeneity could result in higher filter outlet ammonium concentrations....

  6. Synthetic ultraviolet light filtering chemical contamination of coastal waters of Virgin Islands national park, St. John, U.S. Virgin Islands.

    Science.gov (United States)

    Bargar, Timothy A; Alvarez, David A; Garrison, Virginia H

    2015-12-15

    Contamination of surface waters by synthetic ultraviolet light (UV) filtering chemicals is a concern for the Virgin Islands National Park (VINP). Discrete water samples were collected from VINP bays to determine UV filter chemical presence in the coastal waters. Spatial distribution and the potential for partitioning between subsurface waters and the sea surface microlayer (SML) were also examined. The UV filter chemicals 4-methylbenzylidene camphor, benzophenone-3, octinoxate, homosalate, and octocrylene were detected at concentrations up to 6073 ng/L (benzophenone-3). Concentrations for benzophenone-3 and homosalate declined exponentially (r(2)=0.86 to 0.98) with distance from the beach. Limited data indicate that some UV filter chemicals may partition to the SML relative to the subsurface waters. Contamination of VINP coastal waters by UV filter chemicals may be a significant issue, but an improved understanding of the temporal and spatial variability of their concentrations would be necessary to better understand the risk they present.

  7. A Nanoparticulate Photocatalytic Filter for Removal of Trace Contaminant Gases Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Maintaining a healthy atmosphere in closed life support systems is essential for crew well being and success of space missions. Current trace contaminant control...

  8. A Nanoparticulate Photocatalytic Filter for Removal of Trace Contaminant Gases Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Maintaining a healthy atmosphere in closed life support systems is necessary for the well being of the crew and success of a space mission. Current trace contaminant...

  9. Use of evidence in 3 local level HEPA policies in Denmark

    DEFF Research Database (Denmark)

    Jakobsen, Mette Winge; Juel Lau, Cathrine; Skovgaard, Thomas

    2013-01-01

    of relevant evidence for HEPA, resources as well as organizational structure, culture and capacity. Discussion: Our insight into the actual impact of research in HEPA policy making is still sketchy. However, projects such as REPOPA will help to further our understanding of how research and other kind...... activity (HEPA) policies in 7 countries. This presentation draws on the Danish results of the policy analyses. Focus is on the use and the type of research used in three local level HEPA policies in Denmark. Methods: Three municipal level policies were selected for further investigation. Document analysis...

  10. Assessing the fate of biodegradable volatile organic contaminants in unsaturated soil filter systems

    Science.gov (United States)

    Thullner, Martin; de Biase, Cecilia; Hanzel, Joanna; Reger, Daniel; Wick, Lukas; Oswald, Sascha; van Afferden, Manfred; Schmidt, Axel; Reiche, Nils; Jechalke, Sven

    2010-05-01

    The assessment of contaminant biodegradation in the subsurface is challenged by various abiotic processes leading to a reduction of contaminant concentration without a destructive mass removal of the contaminant. In unsaturated porous media, this interplay of processes is further complicated by volatilization. Many organic contaminants are sufficiently volatile to allow for significant fluxes from the water phase into the soil air, which can eventually lead to an emission of contaminants into the atmosphere. Knowledge of the magnitude of these emissions is thus required to evaluate the efficiency of bioremediation in such porous media and to estimate potential risks due to these emissions. In the present study, vertical flow constructed wetlands were investigated at the pilot scale as part of the SAFIRA II project. The investigated wetland system is intermittently irrigated by contaminated groundwater containing the volatile compounds benzene and MTBE. Measured concentration at the in- and outflow of the system demonstrate a high mass removal rate, but the highly transient flow and transport processes in the system challenge the quantification of biodegradation and volatilization and their contribution to the observed mass removal. By a combination of conservative solute tracer tests, stable isotope fractionation and measurements of natural radon concentration is the treated groundwater is was possible to determine the contribution of biodegradation and volatilization to total mass removal. The results suggest that for the investigated volatile compounds biodegradation is the dominating mass removal process with volatilization contributing only to minor or negligible amounts. These results can be confirmed by reactive transport simulations and were further supported by laboratory studies showing that also gas phase gradients of volatile compounds can be affected by biodegradation suggesting the unsaturated zone to act as a biofilter for contaminants in the soil air.

  11. Evaluation of the Hydrophobic Grid Membrane Filter for the Enumeration of Moulds and Yeasts in Naturally-Contaminated Foods

    Directory of Open Access Journals (Sweden)

    V.H. Tournas

    2009-01-01

    Full Text Available Over 240 food samples from six food groups (tree nuts, grains and grain products, dried fruits, fresh produce, fruit juice, and dairy products were tested for levels of fungal contamination using the NEO-GRID hydrophobic grid membrane filter (HGMF and the FDA official (BAM method. Results showed that HGMF performed very well for all tested commodities giving yeast and mould (YM counts similar to those of the BAM (reference method. Statistical analysis of the data (t-test revealed no significant differences between the two methods for all foods tested. Regression analysis showed that there was a good fit linear relationship between the two methods for most of the commodities examined. Some difficulties were encountered during counting of the colonies on HGMF since the size of the grid is very small and the number of possible colonies per plate can reach 1600.

  12. Evaluation of the Hydrophobic Grid Membrane Filter for the Enumeration of Moulds and Yeasts in Naturally-Contaminated Foods

    Directory of Open Access Journals (Sweden)

    V.H. Tournas

    2009-07-01

    Full Text Available Over 240 food samples from six food groups (tree nuts, grains and grain products, dried fruits, fresh produce, fruit juice, and dairy products were tested for levels of fungal contamination using the NEO-GRID hydrophobic grid membrane filter (HGMF and the FDA official (BAM method. Results showed that HGMF performed very well for all tested commodities giving yeast and mould (YM counts similar to those of the BAM (reference method. Statistical analysis of the data (t-test revealed no significant differences between the two methods for all foods tested. Regression analysis showed that there was a good fit linear relationship between the two methods for most of the commodities examined. Some difficulties were encountered during counting of the colonies on HGMF since the size of the grid is very small and the number of possible colonies per plate can reach 1600.

  13. An effect of containment filtered venting system on scale of contamination under severe accident

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Ju young; Lee, Jai-ki [Hanyang Univ., Seoul (Korea, Republic of)

    2016-02-15

    Some countries are expected to expand the scope of the Emergency Planning Zone(EPZ) by the influence of Fukushima accident. However, if the equipment, which is able to mitigate the severe accident consequences, is installed, unnecessary costs for an expansion of emergency planning zone will be reduced. The International Nuclear Safety Advisory Group (INSAC) has suggested to mitigate severe accidents by installing The Filtered Containment Venting System (FCVS). The probabilistic assessment code MACCS2 was used to calculate the effective radiation dose with and without FCVS to determine the effective reduction by the installation of a FCVS.

  14. Contamination impact of station brush fire on cleanroom facilities

    Science.gov (United States)

    Carey, Philip A.; Blakkolb, Brian K.

    2010-08-01

    Brush and forest fires, both naturally occurring and anthropogenic in origin, in proximity to space flight hardware processing facilities raise concerns about the threat of contamination resulting from airborne particulate and molecular components of smoke. Perceptions of the severity of the threat are possibly heightened by the high sensitivity of the human sense of smell to some components present in the smoke of burning vegetation. On August 26th, 2009, a brushfire broke out north of Pasadena, California, two miles from the Jet Propulsion Laboratory. The Station Fire destroyed over 160,000 acres, coming within a few hundred yards of JPL. Smoke concentrations on Lab were very heavy over several days. All Lab operations were halted, and measures were taken to protect personnel, critical hardware, and facilities. Evaluation of real-time cleanroom monitoring data, visual inspection of facilities, filter systems, and analysis of surface cleanliness samples revealed facility environments and hardware were minimally effected. Outside air quality easily exceeded Class Ten Million. Prefilters captured most large ash and soot; multi-stage filtration greatly minimized the impact on the HEPA/ULPA filters. Air quality in HEPA filtered spacecraft assembly cleanrooms remained within Class 10,000 specification throughout. Surface cleanliness was minimally affected, as large particles were effectively removed from the airstream, and sub-micron particles have extremely long settling rates. Approximate particulate fallout within facilities was 0.00011% area coverage/day compared to 0.00038% area coverage/day during normal operations. Deposition of condensable airborne components, as measured in real time, peaked at approximately 1.0 ng/cm2/day compared to 0.05 ng/cm2/day nominal.

  15. Contamination Impact of Station Brush Fire on Cleanroom Facilities

    Science.gov (United States)

    Carey, Phil; Blakkolb, Brian

    2010-01-01

    Brush and forest fires, both naturally occurring and anthropogenic in origin, in proximity to space flight hardware processing facilities raise concerns about the threat of contamination resulting from airborne particulate and molecular components of smoke. Perceptions of the severity of the threat are possibly heightened by the high sensitivity of the human sense of smell to some components present in the smoke of burning vegetation.On August 26th, 2009, a brushfire broke out north of Pasadena, California, two miles from the Jet Propulsion Laboratory. The Station Fire destroyed over 160,000 acres, coming within a few hundred yards of JPL. Smoke concentrations on Lab were very heavy over several days. All Lab operations were halted, and measures were taken to protect personnel, critical hardware, and facilities. Evaluation of real-time cleanroom monitoring data, visualinspection of facilities, filter systems, and analysis of surface cleanliness samples revealed facility environments andhardware were minimally effected.Outside air quality easily exceeded Class Ten Million. Prefilters captured most large ash and soot; multi-stage filtration greatly minimized the impact on the HEPA/ULPA filters. Air quality in HEPA filtered spacecraft assembly cleanrooms remained within Class 10,000 specification throughout. Surface cleanliness was inimally affected, as large particles were effectively removed from the airstream, and sub-micron particles have extremely long settling rates. Approximate particulate fallout within facilities was 0.00011% area coverage/day compared to 0.00038% area coverage/day during normal operations. Deposition of condensable airborne components, as measured in real time, peaked at approximately1.0 ng/cm2/day compared to 0.05 ng/cm2/day nominal.

  16. Fingerprint testing of contaminated ventilation extract filter systems at Sizewell B

    Energy Technology Data Exchange (ETDEWEB)

    Meddings, P.; Patel, S. [Nuclear Electric plc, Barnwood (United Kingdom)

    1996-06-01

    Sizewell B is Nuclear Electric`s latest power station, and the Pressurised Water Reactor (PWR) design on which it is based represents a ``first`` for the UK. One of the integral components of the plant is the heating, ventilation and air-conditioning (HVAC) system, which performs a contamination control and gaseous waste management function for the site. During the commissioning of Sizewell B Power Station the extract systems of the HVAC plant underwent a procedure known as ``fingerprinting``. This entailed the characterisation of the facilities provided to test the filtration plant during its lifetime. The assessment of their adequacy was then used to identify necessary modifications and/or to propose the manner in which future in situ performance testing would be carried out. The paper outlines the basic principles and procedure that was used to ``fingerprint`` test systems during the commissioning of Sizewell B. A specific example is presented to demonstrate the process. (UK).

  17. Use of sugarcane filter cake and nitrogen, phosphorus and potassium fertilization in the process of bioremediation of soil contaminated with diesel.

    Science.gov (United States)

    Tellechea, Fernando Reynel Fundora; Martins, Marco Antônio; da Silva, Alexsandro Araujo; da Gama-Rodrigues, Emanuela Forestieri; Martins, Meire Lelis Leal

    2016-09-01

    This study evaluated the use of sugarcane filter cake and nitrogen, phosphorus and potassium (NPK) fertilization in the bioremediation of a soil contaminated with diesel fuel using a completely randomized design. Five treatments (uncontaminated soil, T1; soil contaminated with diesel, T2; soil contaminated with diesel and treated with 15 % (wt) filter cake, T3; soil contaminated with diesel and treated with NPK fertilizer, T4; and soil contaminated with diesel and treated with 15 % (wt) filter cake and NPK fertilizer, T5) and four evaluation periods (1, 60, 120, and 180 days after the beginning of the experiment) were used according to a 4 × 5 factorial design to analyze CO2 release. The variables total organic carbon (TOC) and total petroleum hydrocarbons (TPH) remaining in the soil were analyzed using a 5 × 2 factorial design, with the same treatments described above and two evaluation periods (1 and 180 days after the beginning of the experiment). In T3 and T5, CO2 release was significantly higher, compared with the other treatments. Significant TPH removal was observed on day 180, when percent removal values were 61.9, 70.1, 68.2, and 75.9 in treatments T2, T3, T4, and T5, respectively, compared with the initial value (T1).

  18. Extended-life nuclear air cleaning filters via dynamic exclusion prefilters

    Energy Technology Data Exchange (ETDEWEB)

    Wright, S.R.; Crouch, H.S.; Bond, J.H. [Micro Composite Materials Corp., Durham, NC (United States)

    1997-08-01

    The primary objective of this investigation was to ascertain if a dynamic, self-cleaning particulate exclusion precleaner, designed for relatively large dust removal (2 to 100+ {mu}m diameter particles) from helicopter turbine inlets, could be extended to submicron filtration. The improved device could be used as a prefilter for HEPA filtration systems, significantly increasing service life. In nuclear air cleaning, its use would reduce the amount of nuclear particulate matter that would otherwise be entrapped in the HEPA filter cartridge/panel, causing fouling and increased back pressure, as well as requiring subsequent disposal of the contaminated media at considerable expense. A unique (patent-pending) mechanical separation device has recently been developed to extract particulate matter from fluid process streams based on a proprietary concept called Boundary Layer Momentum Transfer (BLMT). The device creates multiple boundary layers that actively exclude particles from entering the perimeter of the device, while allowing air to traverse the boundaries relatively unimpeded. A modified two-dimensional (2-D) computerized flow simulation model was used to assist in the prototype design. Empirical results are presented from particle breakthrough and AP experiments obtained from a reduced-scale prototype filter. Particles larger than 0.23 {mu}m were actively excluded by the prototype, but at a higher pressure drop than anticipated. Experimental data collected indicates that the filter housing and the inlet flow configuration may contribute significantly to improvements in device particle separation capabilities. Furthermore, preliminary experiments have shown that other downstream pressure drop considerations (besides those just across the spinning filtration disks) must be included to accurately portray the AP across the device. Further detailed quantitative investigations on a larger scale (1,000 CFM) prototype are warranted. 3 refs., 5 figs., 2 tabs.

  19. 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

  20. Flowrate testing of the bag filter LANCS-BOP 6CPVC-1.5-2SPVC (LANCS Industries) at 1 psig

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Murray E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Currie, Karissa Lyn [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Berg, Charlotte Katherine [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-13

    The air flowrate through a flexible HEPA grade filter (Part LANCS-BOP 6CPVC-1.5-2SPVC www.lancsindustries.com) was measured at 48 ALPM for a differential pressure drop of 1.0 psig (28 inWC, 7.0 kPa). These filters are rated by the manufacturer to have a flowrate of 3 ALPM at a differential pressure drop of 1 inWC (0.25 kPa). The Los Alamos National Laboratory Aerosol Engineering Facility used one of their test rigs (originally developed to measure the pressure drop in capsule HEPA filters) to measure the airflow through the LANCS bag filter.

  1. Leak test of the charcoal filter in the nuclear facility

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Sang Yeol; Lee, Key Soon; Hong, Kwon Pyo; Oh, Yon Woo; Park, Dae Kyu; Ahn, Sang Bok; Choo, Yong Sun; Kim, Sung Jung

    1998-06-01

    In the heating, ventilation and air conditioning(HVAC) system, pre-filter, HEPA(high efficiency particle air) filter and charcoal filter are instrumented in order to filter off the radioactive substance in the nuclear facility. Equipment of the charcoal filter off the radioactive substance in the nuclear facility. Equipment of the charcoal filter at the hot cell where manipulates the nuclear fuel irradiated in the nuclear reactor is essential for shutting off the leakage of the radioiodine which is produced from the cutting procedures of nuclear fuel. Also, the leak test of installed filter should be performed perfectly. In addition, charcoal filter is instrumented to filter the radioactive gas such as radioiodine which is produced in the nuclear facility. In this technical report, the theoretical discussion, the experimental procedures and the precautions of the leak test of charcoal filter are described. (author). 8 refs., 4 tabs., 8 figs.

  2. Engineering Task Plan for Hepa Filter Differential Pressure (DP) Fan Interlock Upgrades

    Energy Technology Data Exchange (ETDEWEB)

    SIMONS, S.R.

    2000-05-19

    This document provides a plan for installation of Differential Pressure (DP) fan interlocks on the primary ventilation systems in selected Tank Farm facilities. This plan contains the engineering tasks required for installation and is summarized by the Acceptance for Beneficial Use list. Individuals responsible for each task are identified and scheduled accordingly.

  3. Applications of nonwoven filter media

    Energy Technology Data Exchange (ETDEWEB)

    1988-11-01

    The multi-client technical and marketing report, Nonwovens in Filtration (1987) World Wide, has been completed by Filter Media Consulting, Inc. According to this 450-page report, $818 million in sales worldwide in nonwoven filter media represents a substantial segment of the entire nonwoven market. This total is mainly roll goods with a few exceptions. Meltblown composites represent $108 million, 13% of the total, and is the fastest growing segment as compared to needled felts, dry formed, thermobonded, spunbonded, wet laid and other unique processes, all extensively covered in this report. Included are 20 filtration applications covered in 190 pages, such as baghouse and dust filtration, Torit-type cartridge filters, HEPA/ULPA filtration, and heating, ventilation and air conditioning. Major markets are addressed, and trends in different fields are highlighted throughout the report.

  4. Differences in TCDD-elicited gene expression profiles in human HepG2, mouse Hepa1c1c7 and rat H4IIE hepatoma cells

    Directory of Open Access Journals (Sweden)

    Burgoon Lyle D

    2011-04-01

    Full Text Available Abstract Background 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD is an environmental contaminant that elicits a broad spectrum of toxic effects in a species-specific manner. Current risk assessment practices routinely extrapolate results from in vivo and in vitro rodent models to assess human risk. In order to further investigate the species-specific responses elicited by TCDD, temporal gene expression responses in human HepG2, mouse Hepa1c1c7 and rat H4IIE cells were compared. Results Microarray analysis identified a core set of conserved gene expression responses across species consistent with the role of AhR in mediating adaptive metabolic responses. However, significant species-specific as well as species-divergent responses were identified. Computational analysis of the regulatory regions of species-specific and -divergent responses suggests that dioxin response elements (DREs are involved. These results are consistent with in vivo rat vs. mouse species-specific differential gene expression, and more comprehensive comparative DRE searches. Conclusions Comparative analysis of human HepG2, mouse Hepa1c1c7 and rat H4IIE TCDD-elicited gene expression responses is consistent with in vivo rat-mouse comparative gene expression studies, and more comprehensive comparative DRE searches, suggesting that AhR-mediated gene expression is species-specific.

  5. Remediation of groundwater contaminated with MTBE and benzene: the potential of vertical-flow soil filter systems

    NARCIS (Netherlands)

    Afferden, M. van; Rahman, K.Z.; Mosig, P.; De Biase, C.; Thullner, M.; Oswald, S.E.; Müller, R.A.

    2011-01-01

    Field investigations on the treatment of MTBE and benzene from contaminated groundwater in pilot or full-scale constructed wetlands are lacking hugely. The aim of this study was to develop a biological treatment technology that can be operated in an economic, reliable and robust mode over a long per

  6. Remediation of groundwater contaminated with MTBE and benzene: the potential of vertical-flow soil filter systems

    NARCIS (Netherlands)

    Afferden, M. van; Rahman, K.Z.; Mosig, P.; De Biase, C.; Thullner, M.; Oswald, S.E.; Müller, R.A.

    2011-01-01

    Field investigations on the treatment of MTBE and benzene from contaminated groundwater in pilot or full-scale constructed wetlands are lacking hugely. The aim of this study was to develop a biological treatment technology that can be operated in an economic, reliable and robust mode over a long

  7. Leaks in nuclear grade high efficiency aerosol filters

    Energy Technology Data Exchange (ETDEWEB)

    Scripsick, Ronald Clyde [Univ. of California, Davis, CA (United States)

    1994-07-01

    Nuclear grade high efficiency aerosol filters, also known as high efficiency particulate air (HEPA) filters, are commonly used in air cleaning systems for removal of hazardous aerosols. Performance of the filter units is important in assuring health and environmental protection. The filter units are constructed from pleated packs of fiberglass filter media sealed into rigid frames. Results of previous studies on such filter units indicate that their performance may not be completely predicted by ideal performance of the fibrous filter media. In this study, departure from ideal performance is linked to leaks existing in filter units and overall filter unit performance is derived from independent performance of the individual filter unit components. The performance of 14 nuclear grade HEPA filter units (size 1, 25 cfm) with plywood frames was evaluated with a test system that permitted independent determination of penetration as a function of particle size for the whole filter unit, the filter unit frame, and the filter media pack. Tests were performed using a polydisperse aerosol of di-2-ethylhexyl phthalate with a count median diameter of 0.2 {mu}m and geometric standard deviation of 1.6. Flow rate and differential pressure were controlled from 1% to 100% of design values. Particle counts were made upstream and downstream of the filter unit with an optical particle counter (OPC). The OPC provided count information in 28 size channels over the particle diameter range from 0.1 to 0.7 μm. Results provide evidence for a two component leak model of filler unit performance with: (1) external leaks through filter unit frames, and (2) internal leaks through defects in the media and through the seal between the media pack and frame. For the filter units evaluated, these leaks dominate overall filter unit performance over much of the flow rate and particle size ranges tested.

  8. 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...

  9. Bisphenol a induces steatosis in HepaRG cells using a model of perinatal exposure.

    Science.gov (United States)

    Bucher, Simon; Jalili, Pégah; Le Guillou, Dounia; Begriche, Karima; Rondel, Karine; Martinais, Sophie; Zalko, Daniel; Corlu, Anne; Robin, Marie-Anne; Fromenty, Bernard

    2017-03-01

    Human exposure to bisphenol A (BPA) could favor obesity and related metabolic disorders such as hepatic steatosis. Investigations in rodents have shown that these deleterious effects are observed not only when BPA is administered during the adult life but also with different protocols of perinatal exposure. Whether perinatal BPA exposure could pose a risk in human is currently unknown, and thus appropriate in vitro models could be important to tackle this major issue. Accordingly, we determined whether long-term BPA treatment could induce steatosis in human HepaRG cells by using a protocol mimicking perinatal exposure. To this end, the kinetics of expression of seven proteins differentially expressed during liver development was determined during a 4-week period of cell culture required for proliferation and differentiation. By analogy with data reported in rodents and humans, our results indicated that the period of cell culture around day 15 and day 18 after seeding could be considered as the "natal" period. Consequently, HepaRG cells were treated for 3 weeks with BPA (from 0.2 to 2000 nM), with a treatment starting during the proliferating period. BPA was able to induce steatosis with a nonmonotonic dose response profile, with significant effects on neutral lipids and triglycerides observed for the 2 nM concentration. However, the expression of many enzymes involved in lipid and carbohydrate homeostasis was unchanged in exposed HepaRG cells. The expression of other potential BPA targets and enzymes involved in BPA biotransformation was also determined, giving answers as well as new questions regarding the mechanisms of action of BPA. Hence, HepaRG cells provide a valuable model that can prove useful for the toxicological assessment of endocrine disruptors on hepatic metabolisms, in particular in the developing liver. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1024-1036, 2017. © 2016 Wiley Periodicals, Inc.

  10. 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.

  11. Altered Hepa1-6 cells by dimethyl sulfoxide (DMSO)-treatment induce anti-tumor immunity in vivo.

    Science.gov (United States)

    Jiang, Zhengyu; Zhang, Hongxia; Wang, Ye; Yu, Bin; Wang, Chen; Liu, Changcheng; Lu, Juan; Chen, Fei; Wang, Minjun; Yu, Xinlu; Lin, Jiahao; Pan, Xinghua; Wang, Pin; Zhu, Haiying

    2016-02-23

    Cancer immunotherapy is the use of the immune system to treat cancer. Our current research proposed an optional strategy of activating immune system involving in cancer immunotherapy. When being treated with 2% DMSO in culture medium, Hepa1-6 cells showed depressed proliferation with no significant apoptosis or decreased viability. D-hep cells, Hepa1-6 cells treated with DMSO for 7 days, could restore to the higher proliferation rate in DMSO-free medium, but alteration of gene expression profile was irreversible. Interestingly, tumors from D-hep cells, not Hepa1-6 cells, regressed in wild-type C57BL/6 mice whereas D-hep cells exhibited similar tumorigenesis as Hep1-6 cells in immunodeficient mice. As expected, additional Hepa1-6 cells failed to form tumors in the D-hep-C57 mice in which D-hep cells were eliminated. Further research confirmed that D-hep-C57 mice established anti-tumor immunity against Hepa1-6 cells. Our research proposed viable tumor cells with altered biological features by DMSO-treatment could induce anti-tumor immunity in vivo.

  12. Highly Bactericidal Polyurethane Effective Against Both Normal and Drug-Resistant Bacteria: Potential Use as an Air Filter Coating.

    Science.gov (United States)

    Taylor, Matthew; McCollister, Bruce; Park, Daewon

    2016-03-01

    The battle against the prevalence of hospital-acquired infections has underscored the importance of identifying and maintaining the cleanliness of possible infection transmission sources in the patient's environment. One of the most crucial lines of defense for mitigating the spread of pathogens in a healthcare facility is the removal of microorganisms from the environment by air filtration systems. After removing the pathogenic microorganisms, the filters used in these systems can serve as reservoirs for the pathogens and pose a risk for secondary infection. This threat, combined with the ever-growing prevalence of drug-resistant bacterial strains, substantiates the need for an effective bactericidal air filter. To this end, a broad-spectrum bactericidal polyurethane incorporating immobilized quaternary ammonium groups was developed for use as an air filter coating. In this study, the bactericidal activity of the polymer coating on high-efficiency particulate air (HEPA) filter samples was quantified against eight bacterial strains commonly responsible for nosocomial infection-including drug-resistant strains, and confirmed when applied as a filter coating in conditions mimicking those of its intended application. The coated HEPA filter samples exhibited high bactericidal activity against all eight strains, and the polyurethane was concluded to be an effective coating in rendering HEPA filters bactericidal.

  13. METAL MEDIA FILTERS, AG-1 SECTION FI

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, D.

    2012-05-23

    One application of metal media filters is in various nuclear air cleaning processes including applications for protecting workers, the public and the environment from hazardous and radioactive particles. To support this application the development of the ASME AG-1 FI Standard on Metal Media has been under way for more than ten years. Development of the proposed section has required resolving several difficult issues associated with operating conditions (media velocity, pressure drop, etc.), qualification testing, and quality acceptance testing. Performance characteristics of metal media are dramatically different than the glass fiber media with respect to parameters like differential pressures, operating temperatures, media strength, etc. These differences make existing data for a glass fiber media inadequate for qualifying a metal media filter for AG-1. In the past much work has been conducted on metal media filters at facilities such as Lawrence Livermore National Laboratory (LLNL) and Savannah River National Laboratory (SRNL) to qualify the media as High Efficiency Particulate Air (HEPA) Filters. Particle retention testing has been conducted at Oak Ridge Filter Test Facility and at Air Techniques International (ATI) to prove that the metal media meets or exceeds the 99.97% particle retention required for a HEPA Filter. Even with his testing, data was lacking to complete an AG-1 FI Standard on metal media. With funding secured by Mississippi State University (MSU) from National Nuclear Security Administration (NNSA), a research test stand is being designed and fabricated at MSU's Institute for Clean Energy Technology (ICET) Facility to obtain qualification data on metal media. This in turn will support required data needed for the FI Standard. The paper will discuss in detail how the test stand at MSU will obtain the necessary data to complete the FI Standard.

  14. Summary of Martian Dust Filtering Challenges and Current Filter Development

    Science.gov (United States)

    O'Hara, William J., IV

    2017-01-01

    Traditional air particulate filtering in manned spaceflight (Apollo, Shuttle, ISS, etc.) has used cleanable or replaceable catch filters such as screens and High-Efficiency Particulate Arrestance (HEPA) filters. However, the human mission to Mars architecture will require a new approach. It is Martian dust that is the particulate of concern but the need also applies to particulates generated by crew. The Mars Exploration Program Analysis Group (MEPAG) high-lighted this concern in its Mars Science, Goals, Objectives, Investigations and Priorities document [7], by saying specifically that one high priority investigation will be to "Test ISRU atmospheric processing systems to measure resilience with respect to dust and other environmental challenge performance parameters that are critical to the design of a full-scale system." By stating this as high priority the MEPAG is acknowledging that developing and adequately verifying this capability is critical to success of a human mission to Mars. This architecture will require filtering capabilities that are highly reliable, will not restrict the flow path with clogging, and require little to no maintenance. This paper will summarize why this is the case, the general requirements for developing the technology, and the status of the progress made in this area.

  15. Use of the HepaRG Cell Line to Assess Potential Human Hepatotoxicity of ToxCast™ Chemicals

    Science.gov (United States)

    The HepaRG cell line is a promising model system for predicting human hepatotoxicity in part because of the greater capacity to metabolize chemicals than other cell models. We hypothesized that this cell line would be a relevant model for toxicity testing of industrial chemicals....

  16. PPAR agonists reduce steatosis in oleic acid-overloaded HepaRG cells

    Energy Technology Data Exchange (ETDEWEB)

    Rogue, Alexandra [Inserm UMR 991, 35043 Rennes Cedex (France); Université de Rennes 1, Faculté des Sciences Pharmaceutiques et Biologiques, 35043 Rennes Cedex (France); Biologie Servier, Gidy (France); Anthérieu, Sébastien; Vluggens, Aurore [Inserm UMR 991, 35043 Rennes Cedex (France); Université de Rennes 1, Faculté des Sciences Pharmaceutiques et Biologiques, 35043 Rennes Cedex (France); Umbdenstock, Thierry [Technologie Servier, Orléans (France); Claude, Nancy [Institut de Recherches Servier, Courbevoie (France); Moureyre-Spire, Catherine de la; Weaver, Richard J. [Biologie Servier, Gidy (France); Guillouzo, André, E-mail: Andre.Guillouzo@univ-rennes1.fr [Inserm UMR 991, 35043 Rennes Cedex (France); Université de Rennes 1, Faculté des Sciences Pharmaceutiques et Biologiques, 35043 Rennes Cedex (France)

    2014-04-01

    Although non-alcoholic fatty liver disease (NAFLD) is currently the most common form of chronic liver disease there is no pharmacological agent approved for its treatment. Since peroxisome proliferator-activated receptors (PPARs) are closely associated with hepatic lipid metabolism, they seem to play important roles in NAFLD. However, the effects of PPAR agonists on steatosis that is a common pathology associated with NAFLD, remain largely controversial. In this study, the effects of various PPAR agonists, i.e. fenofibrate, bezafibrate, troglitazone, rosiglitazone, muraglitazar and tesaglitazar on oleic acid-induced steatotic HepaRG cells were investigated after a single 24-hour or 2-week repeat treatment. Lipid vesicles stained by Oil-Red O and triglycerides accumulation caused by oleic acid overload, were decreased, by up to 50%, while fatty acid oxidation was induced after 2-week co-treatment with PPAR agonists. The greatest effects on reduction of steatosis were obtained with the dual PPARα/γ agonist muraglitazar. Such improvement of steatosis was associated with up-regulation of genes related to fatty acid oxidation activity and down-regulation of many genes involved in lipogenesis. Moreover, modulation of expression of some nuclear receptor genes, such as FXR, LXRα and CAR, which are potent actors in the control of lipogenesis, was observed and might explain repression of de novo lipogenesis. Conclusion: Altogether, our in vitro data on steatotic HepaRG cells treated with PPAR agonists correlated well with clinical investigations, bringing a proof of concept that drug-induced reversal of steatosis in human can be evaluated in in vitro before conducting long-term and costly in vivo studies in animals and patients. - Highlights: • There is no pharmacological agent approved for the treatment of NAFLD. • This study demonstrates that PPAR agonists can reduce fatty acid-induced steatosis. • Some nuclear receptors appear to be potent actors in the control

  17. Release behavior of smoke and clogging characteristics of the ventilation filter under the fire accident. Contract research

    Energy Technology Data Exchange (ETDEWEB)

    Takada, Junichi; Watanabe, Koji; Tsukamoto, Michio; Tashiro, Shinsuke [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Hayashi, Shiro [Nippon Muki Corp., Tokyo (Japan); Takita, Koji [Sanzo Environment Engineering Corp., Tokyo (Japan); Abe, Hitoshi [Ministry of Economy Trade and Industry, Tokyo (Japan); Uchiyama, Gunzo [Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan)

    2003-01-01

    In a part of building ventilating installation of reprocessing plant, the pre-filter is equipped in front of a HEPA filter. The pre-filter plays a role in protection and repression of clogging of HEPA filter. However, in a fire accident, it is considered that large smoke generation cause the pre-filter clogging due to smoke loading, increase of differential pressure and breakdown. In Japan Atomic Energy Research Institute, the demonstration tests to confirm the performance of ventilation filters by a fire accident were carried out. In the tests, smoke was generated from burning of the mock solid wastes (gloves made of rubber and/or cloth) or the mock recovered solvent (n-dodecane or tributyl phosphate / n-dodecane). The test data was acquired on generation of smoke, decrease evolution of smoke by transportation through the compositions of ventilation system (cell, duct, damper, filters) and clogging characteristics of the ventilation filters due to smoke loading. From the results, it was found that the performance of the whole of ventilation system was kept even if the pre-filter was breakdown. To adopt the analysis of the increase of differential pressure across the pre-filter using the safety analysis code, CELVA-1D, increase of differential pressure across the pre-filter was expressed by quadratic empirical equation with function of smoke loading per unit filtration area and it coefficients, ({alpha}, {beta}), were estimated. (author)

  18. Evaluation of the ICET Test Stand to Assess the Performance of a Range of Ceramic Media Filter Elements in Support of ASME AG-1 Subsection FO

    Energy Technology Data Exchange (ETDEWEB)

    Schemmel, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-04-26

    High Efficiency Particulate Air (HEPA) filters are defined as extended-medium, dry-type filters with: (1) a minimum particle removal efficiency of no less than 99.97 percent for 0.3 micrometer particles, (2) a maximum, clean resistance of 1.0 inch water column (in. WC) when operated at 1,000 cubic feet per minute (CFM), and (3) a rigid casing that extends the full depth of the medium. Specifically, ceramic media HEPA filters provide better performance at elevated temperatures, are moisture resistant and nonflammable, can perform their function if wetted and exposed to greater pressures, and can be cleaned and reused. This paper describes the modification and design of a large scale test stand which properly evaluates the filtration characteristics of a range of ceramic media filters challenged with a nuclear aerosol agent in order to develop Section FO of ASME AG-1.

  19. The Effect of Aromatic Hydrocarbon Receptor on the Phenotype of the Hepa 1c1c7 Murine Hepatoma Cells in the Absence of Dioxin

    Directory of Open Access Journals (Sweden)

    Feng Wang

    2007-01-01

    Full Text Available The aromatic hydrocarbon receptor (AhR mediates biological responses to certain exogenous ligands, such as the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, and has also been demonstrated to modulate the cell cycle and differentiated state of several cell lines independently of exogenous ligands. In this study, we used DNA micorarray analysis to elucidate the profile of genes responsive to the expression of unliganded AhR by re-introducing AhR into an AhR-deficient mouse derivative (c19 of the mouse hepatoma cell line Hepa1c1c7. 22 gene products were up-regulated and 8 were down-regulated two-fold or more in c19 cells infected with a retroviral vector expressing mouse AhR. Surprisingly, expression of genes involved in cell proliferation or differentiation were not affected by introduction of AhR. AhR also did not restore expression of the albumin gene in c19 cells. Introduction of AhR into c12, a similar AhRdefective mouse hepatoma cell line, also did not restore albumin expression, and furthermore, did not lead to changes in cellular morphology or cell cycle parameters. These observations fail to support the notion that unliganded AhR regulates proliferation and differentiation of liver-derived cells.

  20. International Space Station (ISS) Bacterial Filter Elements (BFEs): Filter Efficiency and Pressure Testing of Returned Units

    Science.gov (United States)

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

    2017-01-01

    The air revitalization system aboard the International Space Station (ISS) provides the vital function of maintaining a clean cabin 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 sedimentation due to the microgravity environment in Low Earth Orbit (LEO). The ISS Environmental Control and Life Support (ECLS) system architecture in the U.S. Segment uses a distributed particulate filtration approach consisting of traditional High-Efficiency Particulate Adsorption (HEPA) media filters deployed at multiple locations in each U.S. Segment module; these filters are referred to as Bacterial Filter Elements, or BFEs. These filters see a replacement interval, as part of maintenance, of 2-5 years dependent on location in the ISS. In this work, we present particulate removal efficiency, pressure drop, and leak test results for a sample set of 8 BFEs returned from the ISS after filter replacement. The results can potentially be utilized by the ISS Program to ascertain whether the present replacement interval can be maintained or extended to balance the on-ground filter inventory with extension of the lifetime of ISS beyond 2024. These results can also provide meaningful guidance for particulate filter designs under consideration for future deep space exploration missions.

  1. A multiscale method to calculate filter blockage

    CERN Document Server

    Dalwadi, Mohit P; Griffiths, Ian M

    2016-01-01

    Filters that act by adsorbing contaminant onto their pore walls will experience a decrease in porosity over time, and may eventually block. As adsorption will generally be larger towards the entrance of a filter, where the concentration of contaminant particles is higher, these effects can also result in a spatially varying porosity. We investigate this dynamic process using an extension of homogenization theory that accounts for a macroscale variation in microstructure. We formulate and homogenize the coupled problems of flow through a filter with a near-periodic time-dependent microstructure, solute transport due to advection, diffusion, and filter adsorption, and filter structure evolution due to the adsorption of contaminant. We use the homogenized equations to investigate how the contaminant removal and filter lifespan depend on the initial porosity distribution for a unidirectional flow. We confirm a conjecture made in Dalwadi et al. (2015) that filters with an initially negative porosity gradient have ...

  2. Preliminary field evaluation of high efficiency steel filters

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, W.; Larsen, G.; Lopez, R. [Lawrence Livermore National Laboratory, CA (United States)] [and others

    1995-02-01

    We have conducted an evaluation of two high efficiency steel filters in the exhaust of an uranium oxide grit blaster at the Y-12 Plant in Oak Ridge Tennessee. The filters were installed in a specially designed filter housing with a reverse air-pulse cleaning system for automatically cleaning the filters in-place. Previous tests conducted on the same filters and housing at LLNL under controlled conditions using Arizona road dust showed good cleanability with reverse air pulses. Two high efficiency steel filters, containing 64 pleated cartridge elements housed in the standard 2` x 2` x 1` HEPA frame, were evaluated in the filter test housing using a 1,000 cfm slip stream containing a high concentration of depleted uranium oxide dust. One filter had the pleated cartridges manufactured to our specifications by the Pall Corporation and the other by Memtec Corporation. Test results showed both filters had a rapid increase in pressure drop with time, and reverse air pulses could not decrease the pressure drop. We suspected moisture accumulation in the filters was the problem since there were heavy rains during the evaluations, and the pressure drop of the Memtec filter decreased dramatically after passing clean, dry air through the filter and after the filter sat idle for one week. Subsequent laboratory tests on a single filter cartridge confirmed that water accumulation in the filter was responsible for the increase in filter pressure drop and the inability to lower the pressure drop by reverse air pulses. No effort was made to identify the source of the water accumulation and correct the problem because the available funds were exhausted.

  3. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT - PHYSICAL REMOVAL OF MICROBIOLOGICAL & PARTICULATE CONTAMINANTS IN DRINKING WATER: US FILTER 3M10C MICROFILTRATION MEMBRANE SYSTEM AT CHULA VISTA, CALIFORNIA

    Science.gov (United States)

    Verification testing of the US Filter 3M10C membrane system was conducted over a 44-day test period at the Aqua 2000 Research Center in Chula Vista, California. The test period extended from July 24, 2002 to September 5, 2002. The source water was a blend of Colorado River and ...

  4. The histone deacetylase inhibiting drug Entinostat induces lipid accumulation in differentiated HepaRG cells

    Science.gov (United States)

    Nunn, Abigail D. G.; Scopigno, Tullio; Pediconi, Natalia; Levrero, Massimo; Hagman, Henning; Kiskis, Juris; Enejder, Annika

    2016-06-01

    Dietary overload of toxic, free metabolic intermediates leads to disrupted insulin signalling and fatty liver disease. However, it was recently reported that this pathway might not be universal: depletion of histone deacetylase (HDAC) enhances insulin sensitivity alongside hepatic lipid accumulation in mice, but the mechanistic role of microscopic lipid structure in this effect remains unclear. Here we study the effect of Entinostat, a synthetic HDAC inhibitor undergoing clinical trials, on hepatic lipid metabolism in the paradigmatic HepaRG liver cell line. Specifically, we statistically quantify lipid droplet morphology at single cell level utilizing label-free microscopy, coherent anti-Stokes Raman scattering, supported by gene expression. We observe Entinostat efficiently rerouting carbohydrates and free-fatty acids into lipid droplets, upregulating lipid coat protein gene Plin4, and relocating droplets nearer to the nucleus. Our results demonstrate the power of Entinostat to promote lipid synthesis and storage, allowing reduced systemic sugar levels and sequestration of toxic metabolites within protected protein-coated droplets, suggesting a potential therapeutic strategy for diseases such as diabetes and metabolic syndrome.

  5. 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.

  6. Filter arrays

    Energy Technology Data Exchange (ETDEWEB)

    Page, Ralph H.; Doty, Patrick F.

    2017-08-01

    The various technologies presented herein relate to a tiled filter array that can be used in connection with performance of spatial sampling of optical signals. The filter array comprises filter tiles, wherein a first plurality of filter tiles are formed from a first material, the first material being configured such that only photons having wavelengths in a first wavelength band pass therethrough. A second plurality of filter tiles is formed from a second material, the second material being configured such that only photons having wavelengths in a second wavelength band pass therethrough. The first plurality of filter tiles and the second plurality of filter tiles can be interspersed to form the filter array comprising an alternating arrangement of first filter tiles and second filter tiles.

  7. Investigation of the Contamination Control in a Cleaning Room with a Moving AGV by 3D Large-Scale Simulation

    Directory of Open Access Journals (Sweden)

    Qing-He Yao

    2013-01-01

    Full Text Available The motions of the airflow induced by the movement of an automatic guided vehicle (AGV in a cleanroom are numerically studied by large-scale simulation. For this purpose, numerical experiments scheme based on domain decomposition method is designed. Compared with the related past research, the high Reynolds number is treated by large-scale computation in this work. A domain decomposition Lagrange-Galerkin method is employed to approximate the Navier-Stokes equations and the convection diffusion equation; the stiffness matrix is symmetric and an incomplete balancing preconditioned conjugate gradient (PCG method is employed to solve the linear algebra system iteratively. The end wall effects are readily viewed, and the necessity of the extension to 3 dimensions is confirmed. The effect of the high efficiency particular air (HEPA filter on contamination control is studied and the proper setting of the speed of the clean air flow is also investigated. More details of the recirculation zones are revealed by the 3D large-scale simulation.

  8. Filter Efficiency and Pressure Testing of Returned ISS Bacterial Filter Elements (BFEs)

    Science.gov (United States)

    Green, Robert D.; Agui, Juan H.; Berger, Gordon M.; Vijayakumar, R.; Perry, Jay L.

    2017-01-01

    The air quality control equipment aboard the International Space Station (ISS) and future deep space exploration vehicles provide the vital function of maintaining a clean cabin 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 sedimentation. The ISS Environmental Control and Life Support (ECLS) system architecture in the U.S. Segment uses a distributed particulate filtration approach consisting of traditional High-Efficiency Particulate Air (HEPA) filters deployed at multiple locations in each U.S. Seg-ment module; these filters are referred to as Bacterial Filter Elements, or BFEs. In our previous work, we presented results of efficiency and pressure drop measurements for a sample set of two returned BFEs with a service life of 2.5 years. In this follow-on work, we present similar efficiency, pressure drop, and leak tests results for a larger sample set of six returned BFEs. The results of this work can aid the ISS Program in managing BFE logistics inventory through the stations planned lifetime as well as provide insight for managing filter element logistics for future exploration missions. These results also can provide meaningful guidance for particulate filter designs under consideration for future deep space exploration missions.

  9. Impact of runoff infiltration on contaminant accumulation and transport in the soil/filter media of Sustainable Urban Drainage Systems: A literature review.

    Science.gov (United States)

    Tedoldi, Damien; Chebbo, Ghassan; Pierlot, Daniel; Kovacs, Yves; Gromaire, Marie-Christine

    2016-11-01

    The increasing use of Sustainable Urban Drainage Systems (SUDS) for stormwater management raises some concerns about the fate of ubiquitous runoff micropollutants in soils and their potential threat to groundwater. This question may be addressed either experimentally, by sampling and analyzing SUDS soil after a given operating time, or with a modeling approach to simulate the fate and transport of contaminants. After briefly reminding the processes responsible for the retention, degradation, or leaching of several urban-sourced contaminants in soils, this paper presents the state of the art about both experimental and modeling assessments. In spite of noteworthy differences in the sampling protocols, the soil parameters chosen as explanatory variables, and the methods used to evaluate the site-specific initial concentrations, most investigations undoubtedly evidenced a significant accumulation of metals and/or hydrocarbons in SUDS soils, which in the majority of the cases appears to be restricted to the upper 10 to 30cm. These results may suggest that SUDS exhibit an interesting potential for pollution control, but antinomic observations have also been made in several specific cases, and the inter-site concentration variability is still difficult to appraise. There seems to be no consensus regarding the level of complexity to be used in models. However, the available data deriving from experimental studies is generally limited to the contamination profiles and a few parameters of the soil, as a result of which "complex" models (including colloid-facilitated transport for example) appear to be difficult to validate before using them for predictive evaluations.

  10. Optimal filtering

    CERN Document Server

    Anderson, Brian D O

    2005-01-01

    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

  11. In situ fabrication of depth-type hierarchical CNT/quartz fiber filters for high efficiency filtration of sub-micron aerosols and high water repellency

    Science.gov (United States)

    Li, Peng; Zong, Yichen; Zhang, Yingying; Yang, Mengmeng; Zhang, Rufan; Li, Shuiqing; Wei, Fei

    2013-03-01

    We fabricated depth-type hierarchical CNT/quartz fiber (QF) filters through in situ growth of CNTs upon quartz fiber (QF) filters using a floating catalyst chemical vapor deposition (CVD) method. The filter specific area of the CNT/QF filters is more than 12 times higher than that of the pristine QF filters. As a result, the penetration of sub-micron aerosols for CNT/QF filters is reduced by two orders of magnitude, which reaches the standard of high-efficiency particulate air (HEPA) filters. Simultaneously, due to the fluffy brush-like hierarchical structure of CNTs on QFs, the pore size of the hybrid filters only has a small increment. The pressure drop across the CNT/QF filters only increases about 50% with respect to that of the pristine QF filters, leading to an obvious increased quality factor of the CNT/QF filters. Scanning electron microscope images reveal that CNTs are very efficient in capturing sub-micron aerosols. Moreover, the CNT/QF filters show high water repellency, implying their superiority for applications in humid conditions.We fabricated depth-type hierarchical CNT/quartz fiber (QF) filters through in situ growth of CNTs upon quartz fiber (QF) filters using a floating catalyst chemical vapor deposition (CVD) method. The filter specific area of the CNT/QF filters is more than 12 times higher than that of the pristine QF filters. As a result, the penetration of sub-micron aerosols for CNT/QF filters is reduced by two orders of magnitude, which reaches the standard of high-efficiency particulate air (HEPA) filters. Simultaneously, due to the fluffy brush-like hierarchical structure of CNTs on QFs, the pore size of the hybrid filters only has a small increment. The pressure drop across the CNT/QF filters only increases about 50% with respect to that of the pristine QF filters, leading to an obvious increased quality factor of the CNT/QF filters. Scanning electron microscope images reveal that CNTs are very efficient in capturing sub-micron aerosols

  12. Treatment of a sulfate-rich groundwater contaminated with perchloroethene in a hydroponic plant root mat filter and a horizontal subsurface flow constructed wetland at pilot-scale.

    Science.gov (United States)

    Chen, Zhongbing; Kuschk, Peter; Paschke, Heidrun; Kästner, Matthias; Müller, Jochen A; Köser, Heinz

    2014-12-01

    A hydroponic plant root mat filter (HPRMF) was compared over 7months with a horizontal subsurface flow constructed wetland (HSSF CW) regarding the removal of perchloroethene (PCE) (about 2 mg L(-1)) from a sulfate- (850 mg L(-1)) and ammonia-rich (50 mg L(-1)) groundwater with a low TOC content. At a mean area specific inflow PCE load of 56 mg m(-2)d(-1), after 4m from inlet, the mean PCE removal during summer time reached 97% in the HPRMF and almost 100% in the HSSF CW. Within the first 2m in the HSSF CW metabolites like dichloroethenes, vinyl chloride and ethene accumulated, their concentrations decreased further along the flow path. Moreover, the tidal operation (a 7-d cycle) in the HSSFCW decreased the accumulation of PCE metabolites within the first 1m of the bed. The carcinogenic degradation metabolite vinyl chloride was not detected in the HPRMF. The smaller accumulation of the degradation metabolites in the HPRMF correlated with its higher redox potential. It can be concluded from this study that HPRMF appears an interesting alternative for special water treatment tasks and that tidal operation will show some positive effects on the removal of the accumulated PCE metabolites in HSSF CW. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Outbreak of Legionnaires' disease on a cruise ship linked to spa-bath filter stones contaminated with Legionella pneumophila serogroup 5.

    Science.gov (United States)

    Kura, F; Amemura-Maekawa, J; Yagita, K; Endo, T; Ikeno, M; Tsuji, H; Taguchi, M; Kobayashi, K; Ishii, E; Watanabe, H

    2006-04-01

    In January 2003, two cases of Legionnaires' disease associated with a ship's cruise were registered in the database of National Epidemiological Surveillance of Infectious Diseases. A 70-year-old male heavy smoker with mild emphysema contracted the disease during a cruise. Legionella pneumophila serogroup (sg) 5 was isolated from the patient's sputum and the ship's indoor spa. The isolate from the spa matched the patient's isolate by genotyping performed by pulsed-field gel electrophoresis (PFGE). The second case was in a 73-year-old female. During epidemiological investigation, a third case of Legionnaire's disease in a 71-year-old male was subsequently diagnosed among passengers on the same ship on the following cruise. Environmental investigation revealed that porous natural stones (Maifanshi) in the filters of the spas had harboured L. pneumophila, a phenomenon which has not been reported except in Japan. This is the first documented evidence of L. pneumophila sg 5 infection on a ship and of porous stones as a source of Legionella infection.

  14. Elements of Clean-room Technology and Contamination Control

    Directory of Open Access Journals (Sweden)

    J.C. Kapoor

    2003-07-01

    Full Text Available The heart of the clean room is the high efticiency particualte air (HEPA/ultra-low penetration air (ULPA filter, which provides the highest level of air cleaning ever achieved by a singleprocess step. Filter technology has seen tremendous growth in terms of ultimate performance and air handling capacity. Mere installation of ULPA filters of 99.99995 per cent efficiency for 0.2 um aerosol is not sufficient for achieving the desired performance of a clean room. Other design aspects like flow fields, face velocity, number of air changes, make-up air fractions and precise control of other environmental parameters (temperature, humidity, airflow, noise, vibrations, electrostatic discharge, etc. are equally important.

  15. Study on Pretreatment of Contaminated Raw Water by the Lava-based Biological Aerated Filter%火山岩BAF预处理污染水源的研究

    Institute of Scientific and Technical Information of China (English)

    陈玮; 田孝禾; 邢岚英; 刘宏远

    2016-01-01

    The efficiency of pretreatment of contaminated raw water by biological aerated filter, which based on the lava rock, was studied in this paper. The results indicated that BAF was effectually purged the contaminant in the raw water under the condition of the air/water ratio at 1∶1;the influent flow was 50 L/h, filtering velocity at 6.4 m/h. During the normal temperature period (11.9~32.9℃), the average removal rate of ammonia, nitrite nitrogen and CODMn were 92.76%, 94.46%and 30.69%, respectively. And during the low temperature period (5.1~10.8℃), the average removal rate of ammonia, nitrite nitrogen and CODMn were 85.82%, 48.42%and 24.15%, respectively. In the whole experiment period, the average removal rate of turbidity and UV254 were 45.68%, 45.68%. BAF, as a pretreatment process, can efficiently remove pollutants, such as ammonia, organic matters, etc.%采用火山岩为填料的曝气生物滤池(BAF)进行了预处理污染水源的试验研究。试验结果表明,在气水比为1∶1,流量为50 L/h,滤速6.4 m/h的条件下,火山岩BAF能有效净化水中的污染物质。其中常温期(11.9~32.9℃),氨氮、亚硝氮和CODMn的平均去除率分别为92.76%、94.46%和30.69%;低温期(5.1~10.8℃),氨氮、亚硝氮和CODMn的平均去除率分别为85.82%、48.42%和24.15%;试验期间对UV254和浊度的平均去除率分别为7.29%,45.68%。因此,火山岩BAF作为预处理工艺能有效去除原水中的氨氮和有机物等污染物。

  16. The Effect of Hyperthermia on DNA in Mouse HepA Cells-An Analysis with Computer and Observation with EM

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A computer analysis system, automated imaging cytometry (AIC), flow cytometry (FCM) and EM, were used to study the relationship of apoptosis and the change of DNA in mouse HepA cells subjected to hyperthermia. Our results showed that pyknotic rate in the 44 ℃ group was significantly increased (P<0. 01 ) when compared with that in the 37 ℃ group, both the diploid rate and aneuploid rate in the 44 ℃ group were significantly decreased (P< 0. 01 ) when compared with that in the 37 ℃ group. The pyknotic rate determined by ALC was in conformity with the apoptotic index (AI) determined by FCM. Under EM, ultrastructures of HapA ells appeared typical apoptosis changes in the 44 ℃ group. We are led to conclude that (1) when the temperature is 42 ℃ or 44 ℃ for 2 h, it did not promote the necrosis of HepA cells; (2) when the temperature is 42 ℃ for 2 h, it did not obviously induce the apoptosis of HepA cells, and the 44 ℃ for 2 h obviously induced the apoptosis of HepA cells; (3) AIC method can be used as an aid for the measurement of apoptotic index. Further study is needed to established it as a novel, simple and convenient method for determining the apoptosis.

  17. Reliability and Validity of the SE-HEPA: Examining Physical Activity- and Healthy Eating-Specific Self-Efficacy among a Sample of Preadolescents

    Science.gov (United States)

    Steele, Michael M.; Burns, Leonard G.; Whitaker, Brandi N.

    2013-01-01

    Objective. The purpose of this study was to examine the psychometric properties of the self-efficacy for healthy eating and physical activity measure (SE-HEPA) for preadolescents. Method. The reliability of the measure was examined to determine if the internal consistency of the measure was adequate (i.e., [alpha]s greater than 0.70). Next, in an…

  18. PLUTONIUM-URANIUM EXTRACTION (PUREX) FACILITY ALARACT DEMONSTRATION FOR FILTER HOUSING

    Energy Technology Data Exchange (ETDEWEB)

    LEBARON GJ

    2008-11-25

    This document presents an As Low As Reasonably Achievable Control Technology (ALARACT) demonstration for evaluating corrosion on the I-beam supporting filter housing No.9 for the 291-A-l emission unit of the Plutonium-Uranium Extraction (PUREX) Facility, located in the 200 East Area of the Hanford Site. The PUREX facility is currently in surveillance and maintenance mode. During a State of Washington, Department of Health (WDOH) 291-A-l emission unit inspection, a small amount of corrosion was observed at the base of a high-efficiency particulate air (HEPA) filter housing. A series of internal and external inspections identified the source of the corrosion material as oxidation of a small section of one of the carbon steel I-beams that provides support to the stainless steel filter housing. The inspections confirmed the corrosion is isolated to one I-beam support location and does not represent any compromise of the structural support or filter housing integrity. Further testing and inspections of the support beam corrosion and its cause were conducted but did not determine the cause. No definitive evidence was found to support any degradation of the housing. Although no degradation of the housing was found, a conservative approach will be implemented. The following actions will be taken: (1) The current operating filter housing No.9 will be removed from service. (2) The only remaining available filter housings (No.1, No.2, and No.3) will be placed in service. These filter housings have new HEPA filters fitted with stainless steel frames and faceguards which were installed in the spring of 2007. (3) Filter housings No.5 and No.10 will be put on standby as backups. To document the assessment of the unit, a draft ALARACT filter housing demonstration for the PUREX filter housing was prepared, and informally provided to WDOH on August 7, 2008. A follow up WDOH response to the draft ALARACT filter housing demonstration for the PUREX filter housing questioned whether

  19. Ultraviolet filters.

    Science.gov (United States)

    Shaath, Nadim A

    2010-04-01

    The chemistry, photostability and mechanism of action of ultraviolet filters are reviewed. The worldwide regulatory status of the 55 approved ultraviolet filters and their optical properties are documented. The photostabilty of butyl methoxydibenzoyl methane (avobenzone) is considered and methods to stabilize it in cosmetic formulations are presented.

  20. Recycling used automotive oil filters

    Science.gov (United States)

    Peaslee, Kent D.

    1994-02-01

    Over 400 million used automotive oil filters are discarded in the United States each year, most of which are disposed of in landfills wasting valuable resources and risking contamination of ground- and surface-water supplies. This article summarizes U.S. bureau of Mines research evaluating scrap prepared from used automotive oil filters. Experimental results show that crushed and drained oil filters have a bulk density that is higher than many typical scrap grades, a chemical analysis low in residual elements (except tin due to use of tin plate in filters), and an overall yield, oil-filter scrap to cast steel, of 76% to 85%, depending on the method used to prepare the scrap.

  1. MMP-2 inhibits PCSK9-induced degradation of the LDL receptor in Hepa1-c1c7 cells.

    Science.gov (United States)

    Wang, Xiang; Berry, Evan; Hernandez-Anzaldo, Samuel; Sun, Difei; Adijiang, Ayinuer; Li, Liang; Zhang, Dawei; Fernandez-Patron, Carlos

    2015-02-13

    Low-density lipoprotein receptor (LDLR) catalyzes the uptake of LDL-cholesterol by liver and peripheral organs. The function of the LDLR is antagonized by pro-protein convertase subtilisin/kexin type 9 (PCSK9), which binds to LDLR at the plasma membrane inducing LDLR degradation. Here, we report that matrix metalloproteinase-2 (MMP-2) interacts with and cleaves PCSK9, as evidenced by proteomic, chemical cross-linkage, blue native-PAGE and domain-specific antibodies Western blot analyses. Furthermore, MMP-2 overexpression renders Hepa1-c1c7 cells resistant to PCSK9-induced LDLR degradation. The data suggest that pathological MMP-2 overexpression may protect the LDLR from PCSK-9-induced degradation.

  2. Tailored liquid chromatography-mass spectrometry analysis improves the coverage of the intracellular metabolome of HepaRG cells.

    Science.gov (United States)

    Cuykx, Matthias; Negreira, Noelia; Beirnaert, Charlie; Van den Eede, Nele; Rodrigues, Robim; Vanhaecke, Tamara; Laukens, Kris; Covaci, Adrian

    2017-03-03

    Metabolomics protocols are often combined with Liquid Chromatography-Mass Spectrometry (LC-MS) using mostly reversed phase chromatography coupled to accurate mass spectrometry, e.g. quadrupole time-of-flight (QTOF) mass spectrometers to measure as many metabolites as possible. In this study, we optimised the LC-MS separation of cell extracts after fractionation in polar and non-polar fractions. Both phases were analysed separately in a tailored approach in four different runs (two for the non-polar and two for the polar-fraction), each of them specifically adapted to improve the separation of the metabolites present in the extract. This approach improves the coverage of a broad range of the metabolome of the HepaRG cells and the separation of intra-class metabolites. The non-polar fraction was analysed using a C18-column with end-capping, mobile phase compositions were specifically adapted for each ionisation mode using different co-solvents and buffers. The polar extracts were analysed with a mixed mode Hydrophilic Interaction Liquid Chromatography (HILIC) system. Acidic metabolites from glycolysis and the Krebs cycle, together with phosphorylated compounds, were best detected with a method using ion pairing (IP) with tributylamine and separation on a phenyl-hexyl column. Accurate mass detection was performed with the QTOF in MS-mode only using an extended dynamic range to improve the quality of the dataset. Parameters with the greatest impact on the detection were the balance between mass accuracy and linear range, the fragmentor voltage, the capillary voltage, the nozzle voltage, and the nebuliser pressure. By using a tailored approach for the intracellular HepaRG metabolome, consisting of three different LC techniques, over 2200 metabolites can be measured with a high precision and acceptable linear range. The developed method is suited for qualitative untargeted LC-MS metabolomics studies. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Contaminated water treatment

    Science.gov (United States)

    Gormly, Sherwin J. (Inventor); Flynn, Michael T. (Inventor)

    2010-01-01

    Method and system for processing of a liquid ("contaminant liquid") containing water and containing urine and/or other contaminants in a two step process. Urine, or a contaminated liquid similar to and/or containing urine and thus having a relatively high salt and urea content is passed through an activated carbon filter to provide a resulting liquid, to remove most of the organic molecules. The resulting liquid is passed through a semipermeable membrane from a membrane first side to a membrane second side, where a fortified drink having a lower water concentration (higher osmotic potential) than the resulting liquid is positioned. Osmotic pressure differential causes the water, but not most of the remaining inorganic (salts) contaminant(s) to pass through the membrane to the fortified drink. Optionally, the resulting liquid is allowed to precipitate additional organic molecules before passage through the membrane.

  4. International Space Station (ISS) Bacterial Filter Elements (BFEs): Filter Efficiency and Pressure Drop Testing of Returned Units

    Science.gov (United States)

    Green, Robert D.; Agui, Juan H.; Vijayakumar, R.; Berger, Gordon M.; Perry, Jay L.

    2017-01-01

    The air quality control equipment aboard the International Space Station (ISS) and future deep space exploration vehicles provide the vital function of maintaining a clean cabin 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 sedimentation. The ISS Environmental Control and Life Support (ECLS) system architecture in the U.S. Segment uses a distributed particulate filtration approach consisting of traditional High-Efficiency Particulate Air (HEPA) filters deployed at multiple locations in each U.S. Seg-ment module; these filters are referred to as Bacterial Filter Elements, or BFEs. In our previous work, we presented results of efficiency and pressure drop measurements for a sample set of two returned BFEs with a service life of 2.5 years. In this follow-on work, we present similar efficiency, pressure drop, and leak tests results for a larger sample set of six returned BFEs. The results of this work can aid the ISS Program in managing BFE logistics inventory through the stations planned lifetime as well as provide insight for managing filter element logistics for future exploration missions. These results also can provide meaningful guidance for particulate filter designs under consideration for future deep space exploration missions.

  5. Food Filter

    Institute of Scientific and Technical Information of China (English)

    履之

    1995-01-01

    A typical food-processing plant produces about 500,000 gallons of waste water daily. Laden with organic compounds, this water usually is evaporated or discharged into sewers.A better solution is to filter the water through

  6. Air filtration in the free molecular flow regime: a review of high-efficiency particulate air filters based on carbon nanotubes.

    Science.gov (United States)

    Li, Peng; Wang, Chunya; Zhang, Yingying; Wei, Fei

    2014-11-01

    Air filtration in the free molecular flow (FMF) regime is important and challenging because a higher filtration efficiency and lower pressure drop are obtained when the fiber diameter is smaller than the gas mean free path in the FMF regime. In previous studies, FMF conditions have been obtained by increasing the gas mean free path through reducing the pressure and increasing the temperature. In the case of carbon nanotubes (CNTs) with nanoscale diameters, it is possible to filtrate in the FMF regime under normal conditions. This paper reviews recent progress in theoretical and experimental studies of air filtration in the FMF regime. Typical structure models of high-efficiency particulate (HEPA) air filters based on CNTs are introduced. The pressure drop in air filters operated in the FMF regime is less than that predicted by the conventional air filtration theory. The thinnest HEPA filters fabricated from single-walled CNT films have an extremely low pressure drop. CNT air filters with a gradient nanostructure are shown to give a much better filtration performance in dynamic filtration. CNT air filters with a hierarchical structure and an agglomerated CNT fluidized bed air filter are also introduced. Finally, the challenges and opportunities for the application of CNTs in air filtration are discussed.

  7. Quantitative filter forensics for indoor particle sampling.

    Science.gov (United States)

    Haaland, D; Siegel, J A

    2017-03-01

    Filter forensics is a promising indoor air investigation technique involving the analysis of dust which has collected on filters in central forced-air heating, ventilation, and air conditioning (HVAC) or portable systems to determine the presence of indoor particle-bound contaminants. In this study, we summarize past filter forensics research to explore what it reveals about the sampling technique and the indoor environment. There are 60 investigations in the literature that have used this sampling technique for a variety of biotic and abiotic contaminants. Many studies identified differences between contaminant concentrations in different buildings using this technique. Based on this literature review, we identified a lack of quantification as a gap in the past literature. Accordingly, we propose an approach to quantitatively link contaminants extracted from HVAC filter dust to time-averaged integrated air concentrations. This quantitative filter forensics approach has great potential to measure indoor air concentrations of a wide variety of particle-bound contaminants. Future studies directly comparing quantitative filter forensics to alternative sampling techniques are required to fully assess this approach, but analysis of past research suggests the enormous possibility of this approach. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. The synthetic retinoid AGN 193109 but not retinoic acid elevates CYP1A1 levels in mouse embryos and Hepa-1c1c7 cells.

    Science.gov (United States)

    Soprano, D R; Gambone, C J; Sheikh, S N; Gabriel, J L; Chandraratna, R A; Soprano, K J; Kochhar, D M

    2001-07-15

    The synthetic retinoid AGN 193109 is a potent pan retinoic acid receptor (RAR) antagonist. Treatment of pregnant mice with a single oral 1 mg/kg dose of this antagonist on day 8 postcoitum results in severe craniofacial (median cleft face or frontonasal deficiency) and eye malformations in virtually all exposed fetuses. Using differential display analysis, we have determined that CYP1A1 mRNA levels are elevated in mouse embryos 6 h following treatment with AGN 193109. Similarly, an elevation in CYP1A1 mRNA levels, protein levels, and aryl hydrocarbon hydoxylase activity occurs in Hepa-1c1c7 cells, with the maximal elevation observed when the cells were treated with 10(-5) M AGN 193109 for 4 to 8 h. Elevation in CYP1A1 mRNA levels in mouse embryos and Hepa-1c1c7 cells does not occur upon treatment with the natural retinoid, all-trans-retinoic acid. Finally, elevation in CYP1A1 mRNA levels was not observed when mutant Hepa-1c1c7 cells, which are defective in either the aryl hydrocarbon receptor (AhR) or aryl hydrocarbon receptor nuclear translocator (ARNT), were treated with AGN 193109. This suggests that the AhR/ARNT pathway and not the RAR/RXR pathway is mediating the elevation of CYP1A1 mRNA levels by AGN 193109, at least in the Hepa-1c1c7 cells. This is the first example of a retinoid that displays the abililty to regulate both the RAR/RXR and AhR/ARNT transcriptional regulatory pathways.

  9. Protective effects of an ethanol extract of Angelica keiskei against acetaminophen-induced hepatotoxicity in HepG2 and HepaRG cells

    Science.gov (United States)

    Choi, Yoon-Hee; Lee, Hyun Sook; Chung, Cha-Kwon

    2017-01-01

    BACKGROUND/OBJECTIVE Although Angelica keiskei (AK) has widely been utilized for the purpose of general health improvement among Asian, its functionality and mechanism of action. The aim of this study was to determine the protective effect of ethanol extract of AK (AK-Ex) on acute hepatotoxicity induced by acetaminophen (AAP) in HepG2 human hepatocellular liver carcinoma cells and HepaRG human hepatic progenitor cells. MATERIALS/METHODS AK-Ex was prepared HepG2 and HepaRG cells were cultured with various concentrations and 30 mM AAP. The protective effects of AK-Ex against AAP-induced hepatotoxicity in HepG2 and HepaRG cells were evaluated using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide, lactate dehydrogenase (LDH) assay, flow cytometry, and Western blotting. RESULTS AK-Ex, when administered prior to AAP, increased cell growth and decreased leakage of LDH in a dose-dependent manner in HepG2 and HepaRG cells against AAP-induced hepatotoxicity. AK-Ex increased the level of Bcl-2 and decreased the levels of Bax, Bok and Bik decreased the permeability of the mitochondrial membrane in HepG2 cells intoxicated with AAP. AK-Ex decreased the cleavage of poly (ADP-ribose) polymerase (PARP) and the activation of caspase-9, -7, and -3. CONCLUSIONS These results demonstrate that AK-Ex downregulates apoptosis via intrinsic and extrinsic pathways against AAP-induced hepatotoxicity. We suggest that AK could be a useful preventive agent against AAP-induced apoptosis in hepatocytes. PMID:28386382

  10. Walking in the high-rise city: a Health Enhancement and Pedometer-determined Ambulatory (HEPA program in Hong Kong

    Directory of Open Access Journals (Sweden)

    Leung AYM

    2014-08-01

    Full Text Available Angela YM Leung,1,2 Mike KT Cheung,3 Michael A Tse,4 Wai Chuen Shum,5 BJ Lancaster,1,6 Cindy LK Lam7 1School of Nursing, 2Research Centre on Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine, University of Hong Kong, 3Centre on Research and Advocacy, Hong Kong Society for Rehabilitation, 4Institute of Human Performance, University of Hong Kong, 5Sheng Kung Hui Holy Carpenter Church Social Services, Hong Kong Special Administrative Region, People’s Republic of China; 6School of Nursing, Vanderbilt University, Nashville, TN, USA; 7Department of Family Medicine and Primary Care, University of Hong Kong, Hong Kong Special Administrative Region, People’s Republic of China Abstract: Due to the lack of good infrastructure in the public estates, many older adults in urban areas are sedentary. The Health Enhancement and Pedometer-Determined Ambulatory (HEPA program was developed to assist older adults with diabetes and/or hypertension to acquire walking exercise habits and to build social support, while engaged in regular physical activity. This study aimed to describe the HEPA program and to report changes in participants’ walking capacity and body strength after 10-week walking sessions. A pre- and postintervention design was used. Pedometers were used to measure the number of steps taken per day before and after the 10-week intervention. Upper and lower body strength, lower body flexibility, and quality of life were assessed. A total of 205 older adults completed the program and all health assessments. After the 10-week intervention, the average number of steps per day increased by 36%, from 6,591 to 8,934. Lower body strength, upper body strength, and aerobic fitness increased significantly after 10 weeks, along with improvement in the 12-item Short Form Health Survey (SF™-12 physical and mental health component summary scores. A social support network was built in the neighborhood, and the local environment was

  11. Formation of GSH-trapped reactive metabolites in human liver microsomes, S9 fraction, HepaRG-cells, and human hepatocytes.

    Science.gov (United States)

    Lassila, Toni; Rousu, Timo; Mattila, Sampo; Chesné, Christophe; Pelkonen, Olavi; Turpeinen, Miia; Tolonen, Ari

    2015-11-10

    The objective was to compare several in vitro human liver-derived subcellular and cellular incubation systems for the formation of GSH-trapped reactive metabolites. Incubations of pooled human liver microsomes, human liver S9 fractions, HepaRG-cells, and human hepatocytes were performed with glutathione as a trapping agent. Experiments with liver S9 were performed under two conditions, using only NADPH and using a full set of cofactors enabling also conjugative metabolism. Ten structurally different compounds were used as a test set, chosen as either "positive" (ciprofloxacin, clozapine, diclofenac, ethinyl estradiol, pulegone, and ticlopidine) or "negative" (caffeine, citalopram, losartan, montelukast) compounds, based on their known adverse reactions on liver or bone marrow. GSH conjugates were observed for seven of the ten compounds; while no conjugates were observed for caffeine, citalopram, or ciprofloxacin. Hepatocyte and HepaRG assays produced a clearly lower number and lower relative abundance of GSH conjugates compared to assays with microsomes and S9 fractions. The major GSH conjugates were different for many compounds in cellular subfractions and cell-based systems. Hepatocytes generally produced a higher number of GSH conjugates than HepaRG cells, although the differences were minor. The results show that the hepatic enzyme system used for screening of GSH-trapped reactive metabolites do have a high impact on the results, and results between different systems are comparable only qualitatively. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Generalised Filtering

    Directory of Open Access Journals (Sweden)

    Karl Friston

    2010-01-01

    Full Text Available We describe a Bayesian filtering scheme for nonlinear state-space models in continuous time. This scheme is called Generalised Filtering and furnishes posterior (conditional densities on hidden states and unknown parameters generating observed data. Crucially, the scheme operates online, assimilating data to optimize the conditional density on time-varying states and time-invariant parameters. In contrast to Kalman and Particle smoothing, Generalised Filtering does not require a backwards pass. In contrast to variational schemes, it does not assume conditional independence between the states and parameters. Generalised Filtering optimises the conditional density with respect to a free-energy bound on the model's log-evidence. This optimisation uses the generalised motion of hidden states and parameters, under the prior assumption that the motion of the parameters is small. We describe the scheme, present comparative evaluations with a fixed-form variational version, and conclude with an illustrative application to a nonlinear state-space model of brain imaging time-series.

  13. Notch filter

    Science.gov (United States)

    Shelton, G. B. (Inventor)

    1977-01-01

    A notch filter for the selective attenuation of a narrow band of frequencies out of a larger band was developed. A helical resonator is connected to an input circuit and an output circuit through discrete and equal capacitors, and a resistor is connected between the input and the output circuits.

  14. Carbon nanotube filters

    Science.gov (United States)

    Srivastava, A.; Srivastava, O. N.; Talapatra, S.; Vajtai, R.; Ajayan, P. M.

    2004-09-01

    Over the past decade of nanotube research, a variety of organized nanotube architectures have been fabricated using chemical vapour deposition. The idea of using nanotube structures in separation technology has been proposed, but building macroscopic structures that have controlled geometric shapes, density and dimensions for specific applications still remains a challenge. Here we report the fabrication of freestanding monolithic uniform macroscopic hollow cylinders having radially aligned carbon nanotube walls, with diameters and lengths up to several centimetres. These cylindrical membranes are used as filters to demonstrate their utility in two important settings: the elimination of multiple components of heavy hydrocarbons from petroleum-a crucial step in post-distillation of crude oil-with a single-step filtering process, and the filtration of bacterial contaminants such as Escherichia coli or the nanometre-sized poliovirus (~25 nm) from water. These macro filters can be cleaned for repeated filtration through ultrasonication and autoclaving. The exceptional thermal and mechanical stability of nanotubes, and the high surface area, ease and cost-effective fabrication of the nanotube membranes may allow them to compete with ceramic- and polymer-based separation membranes used commercially.

  15. In situ fabrication of depth-type hierarchical CNT/quartz fiber filters for high efficiency filtration of sub-micron aerosols and high water repellency.

    Science.gov (United States)

    Li, Peng; Zong, Yichen; Zhang, Yingying; Yang, Mengmeng; Zhang, Rufan; Li, Shuiqing; Wei, Fei

    2013-04-21

    We fabricated depth-type hierarchical CNT/quartz fiber (QF) filters through in situ growth of CNTs upon quartz fiber (QF) filters using a floating catalyst chemical vapor deposition (CVD) method. The filter specific area of the CNT/QF filters is more than 12 times higher than that of the pristine QF filters. As a result, the penetration of sub-micron aerosols for CNT/QF filters is reduced by two orders of magnitude, which reaches the standard of high-efficiency particulate air (HEPA) filters. Simultaneously, due to the fluffy brush-like hierarchical structure of CNTs on QFs, the pore size of the hybrid filters only has a small increment. The pressure drop across the CNT/QF filters only increases about 50% with respect to that of the pristine QF filters, leading to an obvious increased quality factor of the CNT/QF filters. Scanning electron microscope images reveal that CNTs are very efficient in capturing sub-micron aerosols. Moreover, the CNT/QF filters show high water repellency, implying their superiority for applications in humid conditions.

  16. CRYSTAL FILTER TEST SET

    Science.gov (United States)

    CRYSTAL FILTERS, *HIGH FREQUENCY, *RADIOFREQUENCY FILTERS, AMPLIFIERS, ELECTRIC POTENTIAL, FREQUENCY, IMPEDANCE MATCHING , INSTRUMENTATION, RADIOFREQUENCY, RADIOFREQUENCY AMPLIFIERS, TEST EQUIPMENT, TEST METHODS

  17. 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

  18. 3-Nitrobenzanthrone and 3-aminobenzanthrone induce DNA damage and cell signalling in Hepa1c1c7 cells.

    Science.gov (United States)

    Landvik, N E; Arlt, V M; Nagy, E; Solhaug, A; Tekpli, X; Schmeiser, H H; Refsnes, M; Phillips, D H; Lagadic-Gossmann, D; Holme, J A

    2010-02-03

    3-Nitrobenzanthrone (3-NBA) is a mutagenic and carcinogenic environmental pollutant found in diesel exhaust and urban air pollution. In the present work we have characterised the effects of 3-NBA and its metabolite 3-aminobenzanthrone (3-ABA) on cell death and cytokine release in mouse hepatoma Hepa1c1c7 cells. These effects were related to induced DNA damage and changes in cell signalling pathways. 3-NBA resulted in cell death and caused most DNA damage as judged by the amount of DNA adducts ((32)P-postlabelling assay), single strand (ss)DNA breaks and oxidative DNA lesions (comet assay) detected. An increased phosphorylation of H2AX, chk1, chk2 and partly ATM was observed using flow cytometry and/or Western blotting. Both compounds increased phosphorylation of p53 and MAPKs (ERK, p38 and JNK). However, only 3-NBA caused an accumulation of p53 in the nucleus and a translocation of Bax to the mitochondria. The p53 inhibitor pifithrin-alpha inhibited 3-NBA-induced apoptosis, indicating that cell death was a result of the triggering of DNA signalling pathways. The highest phosphorylation of Akt and degradation of IkappaB-alpha (suggesting activation of NF-kappaB) were also seen after treatment with 3-NBA. In contrast 3-ABA increased IL-6 release, but caused little or no toxicity. Cytokine release was inhibited by PD98059 and curcumin, suggesting that ERK and NF-kappaB play a role in this process. In conclusion, 3-NBA seems to have a higher potency to induce DNA damage compatible with its cytotoxic effects, while 3-ABA seems to have a greater effect on the immune system. Copyright 2009 Elsevier B.V. All rights reserved.

  19. Effectiveness of heating, ventilation and air conditioning system with HEPA filter unit on indoor air quality and asthmatic children's health

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ying; Raja, Suresh; Ferro, Andrea R.; Jaques, Peter A.; Hopke, Philip K. [Clarkson University, 8 Clarkson Avenue, Center for Air Resources Engineering and Science, Potsdam, NY 13699 (United States); Gressani, Cheryl; Wetzel, Larry E. [Air Innovations, Inc, 7000 Performance Drive, North Syracuse, NY 13212 (United States)

    2010-02-15

    Poor indoor air quality has been linked to the exacerbation of asthma symptoms in children. Because people spend most of their time indoors, improving indoor air quality may provide some relief to asthma sufferers. A study was conducted to assess whether operating an air cleaning/ventilating unit (HEPAiRx {sup registered}) in a child's bedroom can improve his/her respiratory health. Thirty children diagnosed with asthma were randomly split into two groups. For the first six weeks, group A had the air cleaning/ventilating unit (HEPAiRx {sup registered}) running in the bedrooms of the participants and group B did not; for the second six weeks, both groups had the cleaners running in the bedrooms; and, for the final six weeks, group A turned the cleaners off and group B kept theirs running. Indoor air quality parameters, including temperature, relative humidity, particulate matter (PM 0.5-10 {mu}m), carbon monoxide, carbon dioxide and total volatile organic compound (TVOC) concentrations, were monitored in each bedroom using an AirAdvice indoor air quality multi-meter. As a measure of pulmonary inflammation, exhaled breath condensate (EBC) was collected every sixth day and analyzed for nitrate and pH. Peak expiratory flow (PEF) was also measured. PM and TVOC concentrations decreased with operation of the HEPAiRx an average of 72% and 59%, respectively. The EBC nitrate concentrations decreased significantly and the EBC pH and PEF values increased significantly with operation of the unit (p < 0.001 when comparing on/off sample means). These results indicate that air cleaning in combination with ventilation can effectively reduce symptoms for asthma sufferers. (author)

  20. L-选择素与小鼠肝癌细胞Hepa1-6淋巴道转移的关系%Correlation between L-selectin and lymphatic metastasis potential of mice hepa1-6 cells

    Institute of Scientific and Technical Information of China (English)

    刘芯宇; 张嘉宁

    2013-01-01

    目的 研究L-选择素(L-selectin)与其配体甘露糖受体(mannose receptor,MR)间相互作用与小鼠肝癌细胞Hepa1-6淋巴道转移潜能相关性.方法 构建含有L-selectin的重组载体pcDNA3.1,转染小鼠肝癌细胞 Hepa1-6,筛选稳定表达L-selectin的细胞株.采用免疫组化、RT-PCR、流式细胞、体外黏附试验技术研究小鼠肝癌细胞Hepa1-6中L-selectin的表达及其与肿瘤细胞淋巴道转移潜能的相关性.结果 1重组质粒为目的基因L-selectin.2 Hepa1-6细胞表面有L-selectin表达,阳性率20.2%.3流式细胞仪检测结果表明Hepa1-6细胞表达L-selectin为19.9%.4体外黏附试验结果表明,不具有转移特性的Hepa1-6表达L-selectin后可发生淋巴道转移,L-selectin能与MR结合(P<0.001),介导Hepa1-6的淋巴道转移.结论 Hepa1-6表达目的基因L-selectin后具有淋巴道转移潜能,并能与MR在体外结合,介导肿瘤细胞的淋巴道转移.%Objective To study the correlation between L-selectin and its ligand mannose receptor with mice hepatoma cells Hepal-6 lymphatic metastatic potential. Methods The recombinant plasmids pcDNA3. 1 containing L-selectin was constructed, and transfected mouse liver tumor Hepal-6 cells. The cell strains with a stable expression of L-selectin were screened. Immunochemistry,flow cytometric analysis, RT-PCR and other procedures, in addition to in vitro adhesion assays were performed, to verify the expression of L-selectin on the surface of Hepal -6 cells, and the interactions between L-selectin and tumor cells lymphatic metastasis potential was studied. Results The target gene of recombinant plasmid was L-selectin. L-selectin was expressed on Hepal-6 cell' s surface with the positive rate of 20. 2% . By flow cytometric analysis,the positive expression rate of L-selectin in Hepal-6 cells was 19. 9% . In vitro adhesion assays indicated that this protein was able to bind specifically to MR(P < 0.001) ,and further confirmed that Hepal-6 cells

  1. Immune responses induced by Hepa1-6 hepotoma cell after over-expression SEA and CD80 in vitro%SEA-CD80基因过表达Hepa1-6肝癌细胞体外诱导的免疫学效应

    Institute of Scientific and Technical Information of China (English)

    司少艳; 史亮; 刘俊丽; 宋淑军; 景青萍; 吴继华; 张建中

    2011-01-01

    This study is aimed to determine whether Hepal-6 hepotoma cells could induce antitumor immune response after over-expression Staphylococcus enterotoxin A (SEA) and CD80. Mouse spleen lymphocytes were cocultured with hepal-6 cells infected with empty adenoviruse vector Ad (empty) or the recombinant aden-oviruses of Ad-MMRE-mTERT-B7, Ad-MMRE-mTERT-SEA or Ad-MMRE-mTERT-BIS. Lymphocyte proliferation was assayed by BrdU incorporation using a commercial kit, flow cytometric analysis was used to detect proliferation of T Lymphocyte subgroups. The production of IL-2, TNF-a and IFN-γ was tested by enzyme-linked immunosorbent assay, and antitumor activity of CTL was determined by lactate dehydrogenase release assay. Compared with Hepa1-6 infected with empty adenovirus or without infection, Hepal-6 infected with recombinant adenoviruses could significantly induce proliferatioin of spleen lymphocytes and T Lymphocyte subgroups, enhance IL-2, TNF-a and IFN-γ production and CTL killing activities. The antitumor response was significantly stronger in Hepal-6 cells after dual-gene over-expression than that in Hepal-6 cells after single-gene over-expression. The results indicate that SEA and CD80 expressed on the membrane of Hepal-6 cells by infection with recombinant adenovirus has immune activities. This study provides some experimental evidence for further tumor immune genetherapy with the recombinant adenovirus.%观察经SEA和CD80重组腺病毒感染Hepa1-6肝癌细胞后体外能否诱导抗肿瘤免疫学反应.方法 Hepa1-6细胞分别经空载体腺病毒Ad(空)和重组腺病毒Ad-MMRE-mTERT-B7、Ad-MMRE-mTERT-SEA、Ad-MMRE -mTERT-BIS感染后,和小鼠脾淋巴细胞共培养,然后采用Brdu酶联免疫法(ELISA)检测淋巴细胞增殖;流式细胞术检测T淋巴细胞亚群增殖;ELISA法检测细胞因子IL-2、TNF-α和IFN-γ的产生;LDH释放法检测CTLs对Hepa1-6的杀伤作用.结果与感染空载体腺病毒Ad(空)和未感染Hepa 1-6细胞相比,经重组腺病毒感染的Hepa

  2. CTEPP STANDARD OPERATING PROCEDURE FOR PRE-CLEANING FILTERS AND XAD-2 (SOP-5.10)

    Science.gov (United States)

    This SOP summarizes the method for pre-cleaning XAD-2 resin and quartz fiber filters. The procedure provides a cleaning method to help reduce potential background contamination in the resin and filters.

  3. System for detecting microbial contamination

    NARCIS (Netherlands)

    Gerritse, J.; Groenestijn, J.W.; Zegers, N.D.

    2009-01-01

    The present invention relates to a system for detecting microbial contamination of a liquid specimen comprising a device for concentrating micro-organisms from a liquid specimen, having (i) a hypobaric chamber, (ii) a filter housing comprising a liquid-permeable bed of an adsorbent material and adap

  4. Filter Efficiency and Leak Testing of Returned ISS Bacterial Filter Elements After 2.5 Years of Continuous Operation

    Science.gov (United States)

    Green, Robert D.; Agui, Juan H.; Berger, Gordon M.; Vijayakumar, R.; Perry, Jay L.

    2016-01-01

    The atmosphere revitalization equipment aboard the International Space Station (ISS) and future deep space exploration vehicles provides the vital functions of maintaining a habitable environment for the crew as well as protecting the hardware from fouling by suspended particulate matter. Providing these functions are challenging in pressurized spacecraft cabins because no outside air ventilation is possible and a larger particulate load is imposed on the filtration system due to lack of sedimentation in reduced gravity conditions. The ISS Environmental Control and Life Support (ECLS) system architecture in the U.S. Segment uses a distributed particulate filtration approach consisting of traditional High-Efficiency Particulate Adsorption (HEPA) filters deployed at multiple locations in each module. These filters are referred to as Bacteria Filter Elements (BFEs). As more experience has been gained with ISS operations, the BFE service life, which was initially one year, has been extended to two to five years, dependent on the location in the U.S. Segment. In previous work we developed a test facility and test protocol for leak testing the ISS BFEs. For this work, we present results of leak testing a sample set of returned BFEs with a service life of 2.5 years, along with particulate removal efficiency and pressure drop measurements. The results can potentially be utilized by the ISS Program to ascertain whether the present replacement interval can be maintained or extended to balance the on-ground filter inventory with extension of the lifetime of ISS to 2024. These results can also provide meaningful guidance for particulate filter designs under consideration for future deep space exploration missions.

  5. Convergent Filter Bases

    OpenAIRE

    Coghetto Roland

    2015-01-01

    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).

  6. 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.

  7. Application of biological filters in water treatment systems

    Science.gov (United States)

    Hurley, T. L.; Bambenek, R. A.

    1973-01-01

    Silver chloride placed on or close to barrier kills bacteria as they arrive. Dead bacteria accumulate linearly, whereas previously, live bacteria accumulated exponentially. During continuous 30-day tests, no bacteriological contamination was found downstream of filters with silver chloride added.

  8. Metabolomics analysis of the toxicity pathways of triphenyl phosphate in HepaRG cells and comparison to oxidative stress mechanisms caused by acetaminophen.

    Science.gov (United States)

    Van den Eede, Nele; Cuykx, Matthias; Rodrigues, Robim M; Laukens, Kris; Neels, Hugo; Covaci, Adrian; Vanhaecke, Tamara

    2015-12-01

    Since the publication of REACH guidelines, the need for in vitro tools for toxicity testing has increased. We present here the development of a hepatotoxicity testing tool using human HepaRG cell cultures and metabolomics. HepaRG cells were exposed to either 4mM acetaminophen (APAP) as reference toxicant for oxidative stress or 50 μM triphenyl phosphate (TPHP) as toxicant with unknown toxicity pathways (TPs). After 72 h exposure, cells were subjected to quenching and liquid-liquid extraction which resulted in a polar and an apolar fraction. Analysis of fractions was performed by ultrahigh performance liquid chromatography-high resolution tandem mass spectrometry (UHPLC-QTOF-MS). Significantly up or down regulated metabolites were selected by univariate statistics prior to identification. In order to obtain robust and specific TP biomarkers, the experiment was also repeated using a different culture medium composition to assess which metabolites show consistent changes. Potential biomarkers belonging to different TPs were found for APAP and TPHP. For APAP, the biomarkers were related to a decrease in unsaturated phospholipids, and for TPHP to an accumulation of phosphoglycerolipids and increase of palmitoyl lysophosphatidylcholine. This first proof-of-concept opens new perspectives for the analysis of other (reference) toxicants with different TPs and it can be used to expand the in vitro tool for hepatotoxicity screening of various compounds.

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

    Science.gov (United States)

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

    2015-01-01

    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. The filter element for this system has a non-standard cross-section with a length-to-width ratio (LW) of 6.6. A filter test setup was designed and built to meet industry testing standards. A CFD analysis was performed to initially determine the optimal duct geometry and flow configuration. Both a screen and flow straighter were added to the test duct design to improve flow uniformity and face velocity profiles were subsequently measured to confirm. Flow quality and aerosol mixing assessments show that the duct flow is satisfactory for the intended leak testing. Preliminary leak testing was performed on two different ISS filters, one with known perforations and one with limited use, and results confirmed that the testing methods and photometer instrument are sensitive enough to detect and locate compromised sections of an ISS BFE.Given the engineering constraints in designing spacecraft life support systems, it is anticipated that non-industry standard filters will be required in future designs. This work is focused on developing test protocols for testing the ISS BFE filters, but the methodology is general enough to be extended to other present and future spacecraft filters. These techniques for characterizing the test duct and perform leak testing

  10. NOVEL MICROWAVE FILTER DESIGN TECHNIQUES.

    Science.gov (United States)

    ELECTROMAGNETIC WAVE FILTERS, MICROWAVE FREQUENCY, PHASE SHIFT CIRCUITS, BANDPASS FILTERS, TUNED CIRCUITS, NETWORKS, IMPEDANCE MATCHING , LOW PASS FILTERS, MULTIPLEXING, MICROWAVE EQUIPMENT, WAVEGUIDE FILTERS, WAVEGUIDE COUPLERS.

  11. Miniaturized dielectric waveguide filters

    Science.gov (United States)

    Sandhu, Muhammad Y.; Hunter, Ian C.

    2016-10-01

    Design techniques for a new class of integrated monolithic high-permittivity ceramic waveguide filters are presented. These filters enable a size reduction of 50% compared to air-filled transverse electromagnetic filters with the same unloaded Q-factor. Designs for Chebyshev and asymmetric generalised Chebyshev filter and a diplexer are presented with experimental results for an 1800 MHz Chebyshev filter and a 1700 MHz generalised Chebyshev filter showing excellent agreement with theory.

  12. Fuel cell cathode air filters: Methodologies for design and optimization

    Science.gov (United States)

    Kennedy, Daniel M.; Cahela, Donald R.; Zhu, Wenhua H.; Westrom, Kenneth C.; Nelms, R. Mark; Tatarchuk, Bruce J.

    Proton exchange membrane (PEM) fuel cells experience performance degradation, such as reduction in efficiency and life, as a result of poisoning of platinum catalysts by airborne contaminants. Research on these contaminant effects suggests that the best possible solution to allowing fuel cells to operate in contaminated environments is by filtration of the harmful contaminants from the cathode air. A cathode air filter design methodology was created that connects properties of cathode air stream, filter design options, and filter footprint, to a set of adsorptive filter parameters that must be optimized to efficiently operate the fuel cell. Filter optimization requires a study of the trade off between two causal factors of power loss: first, a reduction in power production due to poisoning of the platinum catalyst by chemical contaminants and second, an increase in power requirements to operate the air compressor with a larger pressure drop from additional contaminant filtration. The design methodology was successfully applied to a 1.2 kW fuel cell using a programmable algorithm and predictions were made about the relationships between inlet concentration, breakthrough time, filter design, pressure drop, and compressor power requirements.

  13. In vivo – in vitro toxicogenomic comparison of TCDD-elicited gene expression in Hepa1c1c7 mouse hepatoma cells and C57BL/6 hepatic tissue

    Directory of Open Access Journals (Sweden)

    Boverhof Darrell R

    2006-04-01

    Full Text Available Abstract Background In vitro systems have inherent limitations in their ability to model whole organism gene responses, which must be identified and appropriately considered when developing predictive biomarkers of in vivo toxicity. Systematic comparison of in vitro and in vivo temporal gene expression profiles were conducted to assess the ability of Hepa1c1c7 mouse hepatoma cells to model hepatic responses in C57BL/6 mice following treatment with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD. Results Gene expression analysis and functional gene annotation indicate that Hepa1c1c7 cells appropriately modeled the induction of xenobiotic metabolism genes in vivo. However, responses associated with cell cycle progression and proliferation were unique to Hepa1c1c7 cells, consistent with the cell cycle arrest effects of TCDD on rapidly dividing cells. In contrast, lipid metabolism and immune responses, representative of whole organism effects in vivo, were not replicated in Hepa1c1c7 cells. Conclusion These results identified inherent differences in TCDD-mediated gene expression responses between these models and highlighted the limitations of in vitro systems in modeling whole organism responses, and additionally identified potential predictive biomarkers of toxicity.

  14. Digital filters in radio detectors of the Pierre Auger Observatory

    Science.gov (United States)

    Szadkowski, Zbigniew; Głas, Dariusz

    2016-09-01

    Ultra-high energy cosmic rays (UHECR) are the most energetic observable particles in Universe. The main challenge in detecting such energetic particles is very small flux. Most experiments focus on detecting Extensive Air Showers (EAS), initiated by primary UHECR particle in interaction with particles of the atmosphere. One of the observation method is detecting the radio emission from the EAS. This emission was theoretically suggested in 1960's, but technological development allow successful detection only in the last several years. This detection technique is used by Auger Engineering Radio Array (AERA). Most of the emission can be observed in frequency band 30 - 80 MHz, however this range is contaminated by radio frequency interferences (RFI). These contaminations must be reduced to decrease false trigger rate. Currently, there are two kind of digital filters used in AERA. One of them is median filter, based on Fast Fourier Transform. Second one is the notch filter, which is a composition of four infinite impulse response filters. Those filters have properly work in AERA radio detectors for many years. Dynamic progress in electronics allows to use more sophisticated algorithms of RFI reduction. Planned modernization of the AERA radio detectors' electronic allows to use finte impulse response (FIR) filters, which can fast adapt to environment conditions. These filters are: Least Mean Squares (LMS) filter and filter based on linear prediction (LP). Tests of new kind of filters are promising and show that FIR filters can be used in next generation radio detectors in AERA experiment.

  15. Filter quality of pleated filter cartridges.

    Science.gov (United States)

    Chen, Chun-Wan; Huang, Sheng-Hsiu; Chiang, Che-Ming; Hsiao, Ta-Chih; Chen, Chih-Chieh

    2008-04-01

    The performance of dust cartridge filters commonly used in dust masks and in room ventilation depends both on the collection efficiency of the filter material and the pressure drop across the filter. Currently, the optimization of filter design is based only on minimizing the pressure drop at a set velocity chosen by the manufacturer. The collection efficiency, an equally important factor, is rarely considered in the optimization process. In this work, a filter quality factor, which combines the collection efficiency and the pressure drop, is used as the optimization criterion for filter evaluation. Most respirator manufacturers pleat the filter to various extents to increase the filtration area in the limit space within the dust cartridge. Six sizes of filter holders were fabricated to hold just one pleat of filter, simulating six different pleat counts, ranging from 0.5 to 3.33 pleats cm(-1). The possible electrostatic charges on the filter were removed by dipping in isopropyl alcohol, and the air velocity is fixed at 100 cm s(-1). Liquid dicotylphthalate particles generated by a constant output atomizer were used as challenge aerosols to minimize particle loading effects. A scanning mobility particle sizer was used to measure the challenge aerosol number concentrations and size distributions upstream and downstream of the pleated filter. The pressure drop across the filter was monitored by using a calibrated pressure transducer. The results showed that the performance of pleated filters depend not only on the size of the particle but also on the pleat count of the pleated filter. Based on filter quality factor, the optimal pleat count (OPC) is always higher than that based on pressure drop by about 0.3-0.5 pleats cm(-1). For example, the OPC is 2.15 pleats cm(-1) from the standpoint of pressure drop, but for the highest filter quality factor, the pleated filter needed to have a pleat count of 2.65 pleats cm(-1) at particle diameter of 122 nm. From the aspect of

  16. Activation of the sonic hedgehog signaling pathway occurs in the CD133 positive cells of mouse liver cancer Hepa 1–6 cells

    Directory of Open Access Journals (Sweden)

    Jeng KS

    2013-08-01

    Full Text Available Kuo-Shyang Jeng,1 I-Shyan Sheen,2 Wen-Juei Jeng,2 Ming-Che Yu,3 Hsin-I Hsiau,3 Fang-Yu Chang,3 Hsin-Hua Tsai31Department of Surgery, Far Eastern Memorial Hospital, Taipei, 2Department of Hepato-Gastroenterology, Chang Gung Memorial Hospital, Linkou Medical Center, Chang Gung University, 3Department of Medical Research, Far Eastern Memorial Hospital, Taipei, Taiwan, Republic of ChinaBackground: The important role of cancer stem cells in carcinogenesis has been emphasized in research. CD133+ cells have been mentioned as liver cancer stem cells in hepatocellular carcinoma (HCC. Some researchers have proposed that the sonic hedgehog (Shh pathway contributes to hepatocarcinogenesis and that the pathway activation occurs mainly in cancer stem cells. We investigated whether the activation of the Shh pathway occurs in CD133+ cells from liver cancer.Materials and methods: We used magnetic sorting to isolate CD133+ cells from mouse cancer Hepa 1–6 cells. To examine the clonogenicity, cell culture and soft agar colony formation assay were performed between CD133+ and CD133- cells. To study the activation of the Shh pathway, we examined the mRNA expressions of Shh, patched homolog 1 (Ptch-1, glioma-associated oncogene homolog 1 (Gli-1, and smoothened homolog (Smoh by real-time polymerase chain reaction of both CD133+ and CD133- cells.Results: The number (mean ± standard deviation of colonies of CD133+ cells and CD133- cells was 1,031.0 ± 104.7 and 119.7 ± 17.6 respectively. This difference was statistically significant (P < 0.001. Their clonogenicity was 13.7% ± 1.4% and 1.6% ± 0.2% respectively with a statistically significant difference found (P < 0.001. CD133+ cells and CD133– cells were found to have statistically significant differences in Shh mRNA and Smoh mRNA (P = 0.005 and P = 0.043 respectively.Conclusion: CD133+ Hepa 1–6 cells have a significantly higher colony proliferation and clonogenicity. The Shh pathway is activated in these

  17. Composing morphological filters

    NARCIS (Netherlands)

    H.J.A.M. Heijmans (Henk)

    1995-01-01

    textabstractA morphological filter is an operator on a complete lattice which is increasing and idempotent. Two well-known classes of morphological filters are openings and closings. Furthermore, an interesting class of filters, the alternating sequential filters, is obtained if one composes openin

  18. Composing morphological filters

    NARCIS (Netherlands)

    Heijmans, H.J.A.M.

    1995-01-01

    A morphological filter is an operator on a complete lattice which is increasing and idempotent. Two well-known classes of morphological filters are openings and closings. Furthermore, an interesting class of filters, the alternating sequential filters, is obtained if one composes openings and closi

  19. In vitro evaluation of major in vivo drug metabolic pathways using primary human hepatocytes and HepaRG cells in suspension and a dynamic three-dimensional bioreactor system.

    Science.gov (United States)

    Darnell, Malin; Ulvestad, Maria; Ellis, Ewa; Weidolf, Lars; Andersson, Tommy B

    2012-10-01

    Major human specific metabolites, not detected during in vivo and in vitro preclinical studies, may cause unexpected drug interactions and toxicity in human and delays in clinical programs. Thus, reliable preclinical tools for the detection of major human metabolites are of high importance. The aim of this study was to compare major drug metabolic pathways in HepaRG cells, a human hepatoma cell line, to fresh human hepatocytes, cryopreserved human hepatocytes, and human in vivo data. Furthermore, the maintenance of cytochrome P450 (P450) and UDP-glucuronosyltransferase (UGT) activities in a dynamic three-dimensional (3D) bioreactor were evaluated over time by using HepaRG cells and human hepatocytes. (14)C-diclofenac and a candidate from AstraZeneca's drug development program, (14)C-AZD6610, which are metabolized by P450 and UGT in vivo, were used as model substrates. The proportion of relevant biotransformation pathways of the investigated drug was clearly different in the various cell systems. The hydroxylation route was favored in primary human hepatocytes, whereas the glucuronidation route was favored in HepaRG cells. The human in vivo metabolite profile of AZD6610 was best represented by human hepatocytes, whereas all major diclofenac metabolites were detected in HepaRG cells. Moreover, the metabolite profiles in cryopreserved and fresh human hepatocytes were essentially the same. The liver bioreactor using both fresh human hepatocytes and HepaRG cells retained biotransformation capacity over 1 week. Thus, the incubation time can be increased from a few hours in suspension to several days in 3D cultures, which opens up for detection of metabolites from slowly metabolized drugs.

  20. Passive Power Filters

    CERN Document Server

    Künzi, R

    2015-01-01

    Power converters require passive low-pass filters which are capable of reducing voltage ripples effectively. In contrast to signal filters, the components of power filters must carry large currents or withstand large voltages, respectively. In this paper, three different suitable filter struc tures for d.c./d.c. power converters with inductive load are introduced. The formulas needed to calculate the filter components are derived step by step and practical examples are given. The behaviour of the three discussed filters is compared by means of the examples. P ractical aspects for the realization of power filters are also discussed.

  1. 三种选择性培养基在滤膜法检测染菌海水中大肠杆菌的效果比较%Comparison of three selective culture media for the detection of Escherichia coil in the bacteria-contaminated seawater by using the filter membrane method

    Institute of Scientific and Technical Information of China (English)

    谢昭聪; 谈书勤; 容清; 郑文丽; 杜林

    2013-01-01

    目的:比较滤膜法使用的三种选择性培养基在染菌海水中检测大肠杆菌的效果.方法:通过染菌海水,使用滤膜法对海水样品进行相应处理后,分别把滤膜放置三种选择性培养基进行培养和菌落计数.结果:滤膜法实验中,mTEC培养基、品红亚硫酸钠培养基和改良品红亚硫酸钠培养基的阳性检出率分别为83%、96%和92%;三种选择性培养基在检测染菌海水样品中,品红亚硫酸钠培养基的回收检出率最高,其次是改良品红亚硫酸钠培养基,最低是mTEC培养基.结论:品红亚硫酸钠培养基和改良品红亚硫酸钠培养基比mTEC培养基更有利于过滤后大肠杆菌的生长;改良品红亚硫酸钠培养基比mTEC培养基更适合用于海水中大肠杆菌的检测.%Objective:To compare the effects of three selective culture media in detection of Escherichia coil from the bacteria-contaminated seawater by using the filter membrane method.Methods:The bacteria-contaminated seawater sample was treated by the filter membrane method,then the filter membranes were placed on three selective culture media for the microorganism cultivation and counting.Results:The positive rates to mTEC agar,the fuchsin basic sodium sulfite agar and modified fuchsin basic sodium sulfite agar used by the filter method were 83%,96% and 92% respectively.Among contaminated seawater samples,the fuchsin basic sodium sulfite agar ranked the first place regarding detection rate,followed by modified fuchsin basic sodium sulfite agar and the mTEC agar.Conclusion:Compared to mTEC agar,the fuchsin basic sodium sulfite agar and modified fuchsin basic sodium sulfite agar were more conducive to the Escherichia coli growing after the filtration process,and modified fuchsin basic sodium sulfite agar was more suitable for the detection of Escherichia coli in the bacteria-contaminated seawater than mTEC

  2. Method of securing filter elements

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Erik P.; Haslam, Jeffery L.; Mitchell, Mark A.

    2016-10-04

    A filter securing system including a filter unit body housing; at least one tubular filter element positioned in the filter unit body housing, the tubular filter element having a closed top and an open bottom; a dimple in either the filter unit body housing or the top of the tubular filter element; and a socket in either the filter unit body housing or the top of the tubular filter element that receives the dimple in either the filter unit body housing or the top of the tubular filter element to secure the tubular filter element to the filter unit body housing.

  3. Water Contamination

    Science.gov (United States)

    ... Statistics Training & Education Policy & Recommendations Fast Facts Healthy Water Sites Healthy Water Drinking Water Healthy Swimming Global ... type=”submit” value=”Submit” /> Healthy Water Home Water Contamination Recommend on Facebook Tweet Share Compartir On ...

  4. Generalized Hampel Filters

    Science.gov (United States)

    Pearson, Ronald K.; Neuvo, Yrjö; Astola, Jaakko; Gabbouj, Moncef

    2016-12-01

    The standard median filter based on a symmetric moving window has only one tuning parameter: the window width. Despite this limitation, this filter has proven extremely useful and has motivated a number of extensions: weighted median filters, recursive median filters, and various cascade structures. The Hampel filter is a member of the class of decsion filters that replaces the central value in the data window with the median if it lies far enough from the median to be deemed an outlier. This filter depends on both the window width and an additional tuning parameter t, reducing to the median filter when t=0, so it may be regarded as another median filter extension. This paper adopts this view, defining and exploring the class of generalized Hampel filters obtained by applying the median filter extensions listed above: weighted Hampel filters, recursive Hampel filters, and their cascades. An important concept introduced here is that of an implosion sequence, a signal for which generalized Hampel filter performance is independent of the threshold parameter t. These sequences are important because the added flexibility of the generalized Hampel filters offers no practical advantage for implosion sequences. Partial characterization results are presented for these sequences, as are useful relationships between root sequences for generalized Hampel filters and their median-based counterparts. To illustrate the performance of this filter class, two examples are considered: one is simulation-based, providing a basis for quantitative evaluation of signal recovery performance as a function of t, while the other is a sequence of monthly Italian industrial production index values that exhibits glaring outliers.

  5. 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.

  6. 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.

  7. Aircraft Recirculation Filter for Air-Quality and Incident Assessment

    Science.gov (United States)

    Eckels, Steven J.; Jones, Byron; Mann, Garrett; Mohan, Krishnan R.; Weisel, Clifford P.

    2015-01-01

    The current research examines the possibility of using recirculation filters from aircraft to document the nature of air-quality incidents on aircraft. These filters are highly effective at collecting solid and liquid particulates. Identification of engine oil contaminants arriving through the bleed air system on the filter was chosen as the initial focus. A two-step study was undertaken. First, a compressor/bleed air simulator was developed to simulate an engine oil leak, and samples were analyzed with gas chromatograph-mass spectrometry. These samples provided a concrete link between tricresyl phosphates and a homologous series of synthetic pentaerythritol esters from oil and contaminants found on the sample paper. The second step was to test 184 used aircraft filters with the same gas chromatograph-mass spectrometry system; of that total, 107 were standard filters, and 77 were nonstandard. Four of the standard filters had both markers for oil, with the homologous series synthetic pentaerythritol esters being the less common marker. It was also found that 90% of the filters had some detectable level of tricresyl phosphates. Of the 77 nonstandard filters, 30 had both markers for oil, a significantly higher percent than the standard filters. PMID:25641977

  8. Guided image filtering.

    Science.gov (United States)

    He, Kaiming; Sun, Jian; Tang, Xiaoou

    2013-06-01

    In this paper, we propose a novel explicit image filter called guided filter. Derived from a local linear model, the guided filter computes the filtering output by considering the content of a guidance image, which can be the input image itself or another different image. The guided filter can be used as an edge-preserving smoothing operator like the popular bilateral filter [1], but it has better behaviors near edges. The guided filter is also a more generic concept beyond smoothing: It can transfer the structures of the guidance image to the filtering output, enabling new filtering applications like dehazing and guided feathering. Moreover, the guided filter naturally has a fast and nonapproximate linear time algorithm, regardless of the kernel size and the intensity range. Currently, it is one of the fastest edge-preserving filters. Experiments show that the guided filter is both effective and efficient in a great variety of computer vision and computer graphics applications, including edge-aware smoothing, detail enhancement, HDR compression, image matting/feathering, dehazing, joint upsampling, etc.

  9. Solar Rejection Filter for Large Telescopes

    Science.gov (United States)

    Hemmati, Hamid; Lesh, James

    2009-01-01

    front aperture filter is integrated with the telescope dome, it will reject heat from the dome and will significantly reduce dome temperature regulation requirements and costs. Also, the filter will protect the telescope optics from dust and other contaminants in the atmosphere. It will be simpler to clean or replace this filter than the telescope primary mirror. It may be necessary to paint the support grid with a highly reflective material to avoid overheating.

  10. [Contaminated heparins].

    Science.gov (United States)

    Monneret, C

    2008-08-01

    In January 2008, following the detection of severe allergic reaction, several batches of heparins were removed from the United-States market. Although less dramatic, comparable side effects were also reported in Germany but not in France despite the fact that low-weight heparins, obtained from contaminated batches of unfractionated heparins, were used to limit shortage. So far, tainted injectable heparin has been linked to over 80 deaths in the USA. Analyses demonstrated that such tainted heparins were contaminated by high levels of chondroïtin persulfate (5-20%), a cheaper hemi-synthetic product. All batches were furnished by several Chinese chemical industries, China representing 50% of all heparins produced worldwide. Thus, contamination of the heparin supply is a worldwide problem. Following this event, the efficiency of the quality insurance, particularly analytical controls before proceeding, remains questionable. The strict respect of the pharmaceutical chain is urgently required to avoid any kind of quality problem in the future.

  11. Computer Aided Filter Design.

    Science.gov (United States)

    1987-12-01

    FIR filter can be described in the following. [Ref. 2] 1. FIR filters with exact linear phase can be easily designed. Linear phase filters are important...response for the four cases of linear phase filter , i.e., even or odd symmetry with an even or odd number of terms, can be written in the form: H (eJ ) = e...Ansari, The Design and Application of Optimal FIR Fractional Phase Filters , IEEE on Acoutics, Speech and Signal Processing, Vol. 2, 1987, pp.896-899. 77 14

  12. A unified Kalman filter

    Science.gov (United States)

    Stubberud, Allen R.

    2017-01-01

    When considering problems of linear sequential estimation, two versions of the Kalman filter, the continuous-time version and the discrete-time version, are often used. (A hybrid filter also exists.) In many applications in which the Kalman filter is used, the system to which the filter is applied is a linear continuous-time system, but the Kalman filter is implemented on a digital computer, a discrete-time device. The two general approaches for developing a discrete-time filter for implementation on a digital computer are: (1) approximate the continuous-time system by a discrete-time system (called discretization of the continuous-time system) and develop a filter for the discrete-time approximation; and (2) develop a continuous-time filter for the system and then discretize the continuous-time filter. Generally, the two discrete-time filters will be different, that is, it can be said that discretization and filter generation are not, in general, commutative operations. As a result, any relationship between the discrete-time and continuous-time versions of the filter for the same continuous-time system is often obfuscated. This is particularly true when an attempt is made to generate the continuous-time version of the Kalman filter through a simple limiting process (the sample period going to zero) applied to the discrete-time version. The correct result is, generally, not obtained. In a 1961 research report, Kalman showed that the continuous-time Kalman filter can be obtained from the discrete-time Kalman filter by taking limits as the sample period goes to zero if the white noise process for the continuous-time version is appropriately defined. Using this basic concept, a discrete-time Kalman filter can be developed for a continuous-time system as follows: (1) discretize the continuous-time system using Kalman's technique; and (2) develop a discrete-time Kalman filter for that discrete-time system. Kalman's results show that the discrete-time filter generated in

  13. Bias aware Kalman filters

    DEFF Research Database (Denmark)

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

    2006-01-01

    . The colored noise filter formulation is extended to correct both time correlated and uncorrelated model error components. A more stable version of the separate filter without feedback is presented. The filters are implemented in an ensemble framework using Latin hypercube sampling. The techniques...... are illustrated on a simple one-dimensional groundwater problem. The results show that the presented filters outperform the standard Kalman filter and that the implementations with bias feedback work in more general conditions than the implementations without feedback. 2005 Elsevier Ltd. All rights reserved....

  14. (Contaminated soil)

    Energy Technology Data Exchange (ETDEWEB)

    Siegrist, R.L.

    1991-01-08

    The traveler attended the Third International Conference on Contaminated Soil, held in Karlsruhe, Germany. The Conference was a status conference for worldwide research and practice in contaminated soil assessment and environmental restoration, with more than 1500 attendees representing over 26 countries. The traveler made an oral presentation and presented a poster. At the Federal Institute for Water, Soil and Air Hygiene, the traveler met with Dr. Z. Filip, Director and Professor, and Dr. R. Smed-Hildmann, Research Scientist. Detailed discussions were held regarding the results and conclusions of a collaborative experiment concerning humic substance formation in waste-amended soils.

  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. 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.

  17. Nicotine Contamination in Particulate Matter Sampling

    Directory of Open Access Journals (Sweden)

    Eric Garshick

    2009-02-01

    Full Text Available We have addressed potential contamination of PM2.5 filter samples by nicotine from cigarette smoke. We collected two nicotine samples – one nicotine sampling filter was placed in-line after the collection of PM2.5 and the other stood alone. The overall correlation between the two nicotine filter levels was 0.99. The nicotine collected on the “stand-alone” filter was slightly greater than that on the “in-line” filter (mean difference = 1.10 μg/m3, but the difference was statistically significant only when PM2.5 was low (≤ 50 μg/m3. It is therefore important to account for personal and secondhand smoke exposure while assessing occupational and environmental PM.

  18. An enhancement algorithm for low quality fingerprint image based on edge filter and Gabor filter

    Science.gov (United States)

    Xue, Jun-tao; Liu, Jie; Liu, Zheng-guang

    2009-07-01

    On account of restriction of man-made and collection environment, the fingerprint image generally has low quality, especially a contaminated background. In this paper, an enhancement algorithm based on edge filter and Gabor filter is proposed to solve this kind of fingerprint image. Firstly, a gray-based algorithm is used to enhance the edge and segment the image. Then, a multilevel block size method is used to extract the orientation field from segmented fingerprint image. Finally, Gabor filter is used to fulfill the enhancement of the fingerprint image. The experiment results show that the proposed enhancement algorithm is effective than the normal Gabor filter algorithm. The fingerprint image enhance by our algorithm has better enhancement effect, so it is helpful for the subsequent research, such as classification, feature exaction and identification.

  19. 水渣滤料-曝气生物滤池去除生活污水中污染物的效能研究%Research on Removal Efficiency of Contamination in Domestic Sewage by Water Quenched Slag Filter Medium Biological Aerated Filter

    Institute of Scientific and Technical Information of China (English)

    于衍真; 韩雯雯; 毕于顺; 冯岩

    2011-01-01

    为解决水渣对环境的污染及综合利用的问题,以水渣为主要原料,添加黏结剂和成孔剂,经混合、成球、养护制成免烧型水渣滤料.在直径为150mm,滤料层高为1500mm的水渣滤料曝气生物滤池(WBAF)中处理生活污水.结果表明,在温度为20~27℃,pH为7.0~8.0,气水比为5:1,进水ρCONDcr=167.58mg/L、浊度=34.60NTU、ρ(NH4^+-N)=36.45mg/L时,相应的出水指标为PCODcr=37.73mg/L、浊度=7.57NTU、ρ(NH4^+-N):5.39mg/L,符合国家污水综合排放标准(GB8978-1996)一级标准.氨氮去除效果明显是因为水渣滤料能溶出碱性物质,为硝化反应提供了碱度.%In order to dipose of the enviromental pollution caused by blast furnace water quenched slag and its comprehensive utilization, water quenched slag was adopted as dominating material mixed with bond and poreforming agent by commingle, conglobate and conseve to make avoiding-burning water quenchde slag filter medium. A pilot scale Water quenched slag filter medium Biological Aerated Filter (WBAF) of 150 mm in diameter and 1 500 mm in media height was tested to treat domestic Sewage. The results showed that PCODcr, = 37.73 mg/L,turbidity = 7.57 NTU,ρ(NH4^+-N) 5.39 mg/L when the corresponding influent concentration was 167.58 mg/L,34.60 NTU ,36.45 mg/L, respectively, under the conditions of T = 20 - 27 ℃ , pH = 7.0 - 8.0 and gas/ liquid = 5: 1. The quality indexes of the domestic sewage after treatment conform with the national discharge standards. The water quenched slag filter medium has higher ammonia nitrogen removal efficiency that because it can sufficiently supply alkalinity by dissolving alkaline substances.

  20. Noise Filtering in Communication with Chaos

    Energy Technology Data Exchange (ETDEWEB)

    Rosa, E. Jr. [Institute for Plasma Research, University of Maryland, College Park, Maryland 20742 (United States); Hayes, S. [Nonlinear Devices Corporation, 8701 Georgia Avenue Suite 501, Silver Spring, Maryland 20910 (United States); Grebogi, C. [Institut fuer Theoretische Physik und Astrophysik, Universitaet Potsdam, PF 601553, D-14415 Potsdam (Germany)

    1997-02-01

    A method, based on fundamental properties of chaotic dynamics, is devised for filtering {ital in-band} noise of an incoming signal generated by a chaotic oscillator. Initially the 2xmod1 map is used to illustrate the procedure and then the method is applied to recover the message encoded in a realistic chaotic signal, after the transmitted signal has been contaminated with noise. {copyright} {ital 1997} {ital The American Physical Society}

  1. Three-zone pupil filters

    Science.gov (United States)

    Sheppard, Colin J. R.; Campos, Juan; Escalera, Juan C.; Ledesma, Silvia

    2008-07-01

    The performance of pupil filters consisting of three zones each of constant complex amplitude transmittance is investigated. For filters where the transmittance is real, different classes of potentially useful filter are identified. These include leaky filters with an inner zone of low amplitude transmittance, pure phase filters with phase change of π, and equal area filters.

  2. 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

  3. Concentric Split Flow Filter

    Science.gov (United States)

    Stapleton, Thomas J. (Inventor)

    2015-01-01

    A concentric split flow filter may be configured to remove odor and/or bacteria from pumped air used to collect urine and fecal waste products. For instance, filter may be designed to effectively fill the volume that was previously considered wasted surrounding the transport tube of a waste management system. The concentric split flow filter may be configured to split the air flow, with substantially half of the air flow to be treated traveling through a first bed of filter media and substantially the other half of the air flow to be treated traveling through the second bed of filter media. This split flow design reduces the air velocity by 50%. In this way, the pressure drop of filter may be reduced by as much as a factor of 4 as compare to the conventional design.

  4. Crux vena cava filter.

    Science.gov (United States)

    Murphy, Erin H; Johnson, Eric D; Kopchok, George E; Fogarty, Thomas J; Arko, Frank R

    2009-09-01

    Inferior vena cava filters are widely accepted for pulmonary embolic prophylaxis in high-risk patients with contraindications to anticoagulation. While long-term complications have been associated with permanent filters, retrievable filters are now available and have resulted in the rapid expansion of this technology. Nonetheless, complications are still reported with optional filters. Furthermore, device tilting and thrombus load may prevent retrieval in up to 30% of patients, thereby eliminating the benefits of this technology. The Crux vena cava filter is a novel, self-centering, low-profile filter that is designed for ease of delivery, retrievability and improved efficacy while limiting fatigue-related device complications. This device has been proven safe and user-friendly in an ovine model and has recently been implanted in human subjects.

  5. CrowdFilter

    DEFF Research Database (Denmark)

    Mortensen, Michael Lind; Wallace, Byron C.; Kraska, Tim

    for complex multi-criteria search problems through crowdsourcing. The CrowdFilter system is capable of supporting both criteria-level labels and n-gram rationales, capturing the human decision making process behind each filtering choice. Using the data provided through CrowdFilter we also introduce a novel......Multi-criteria filtering of mixed open/closed-world data is a time-consuming task, requiring significant manual effort when latent open-world attributes are present. In this work we introduce a novel open-world filtering framework CrowdFilter, enabling automatic UI generation and label elicitation...... multi-criteria active learning method; capable of incorporating labels and n-gram rationales per inclusion criteria, and thus capable of determining both clear includes/excludes, as well as complex borderline cases. By incorporating the active learning approach into the elicitation process of Crowd...

  6. Conservative Noise Filters

    Directory of Open Access Journals (Sweden)

    Mona M.Jamjoom

    2016-05-01

    Full Text Available Noisy training data have a huge negative impact on machine learning algorithms. Noise-filtering algorithms have been proposed to eliminate such noisy instances. In this work, we empirically show that the most popular noise-filtering algorithms have a large False Positive (FP error rate. In other words, these noise filters mistakenly identify genuine instances as outliers and eliminate them. Therefore, we propose more conservative outlier identification criteria that improve the FP error rate and, thus, the performance of the noise filters. With the new filter, an instance is eliminated if and only if it is misclassified by a mutual decision of Naïve Bayesian (NB classifier and the original filtering criteria being used. The number of genuine instances that are incorrectly eliminated is reduced as a result, thereby improving the classification accuracy.

  7. Treatment of hepatitis C virus infection in patients with cirrhosis and predictive value of MELD: Analysis of data from the Hepa-C registry.

    Science.gov (United States)

    Fernández Carrillo, Carlos; Lens, Sabela; Llop, Elba; Pascasio, Juan Manuel; Crespo, Javier; Arenas, Juan; Fernández, Inmaculada; Baliellas, Carme; Carrión, José Antonio; de la Mata, Manuel; Buti, Maria; Castells, Lluís; Albillos, Agustín; Romero, Manuel; Turnes, Juan; Pons, Clara; Moreno-Planas, José María; Moreno-Palomares, José Javier; Fernández-Rodriguez, Conrado; García-Samaniego, Javier; Prieto, Martín; Fernández Bermejo, Miguel; Salmerón, Javier; Badia, Ester; Salcedo, Magdalena; Herrero, José Ignacio; Granados, Rafael; Blé, Michel; Mariño, Zoe; Calleja, José Luis

    2017-02-07

    Direct-acting antiviral agents (DAAs) are highly effective and well tolerated in patients with chronic hepatitis C virus (HCV) infection, including those with compensated cirrhosis. However, fewer data are available in patients with more advanced liver disease. Our retrospective, non-interventional, national, multi-center study in patients from the Spanish Hepa-C registry investigated the effectiveness and safety of interferon-free DAA regimens in patients with advanced liver disease, including those with decompensated cirrhosis, in routine practice (all currently approved regimens were registered). Patients transplanted during treatment or within 12 weeks of completing treatment were excluded. Among 843 cirrhotic patients (Child A, n=564; Child B/C, n=175), 90% achieved sustained virologic response 12 weeks post-treatment (SVR12). Significant differences in SVR12 and relapse rates were observed between Child A and Child B/C patients (94% vs. 78%, and 4% vs. 14%, respectively; both Pdecompensation was the most common SAE (7% overall). Death rate during the study period was 16/843 (2%), significantly higher among Child B/C vs. Child A patients (6.4% vs. 0.9%; Pdecompensated cirrhosis receiving DAAs present lower response rates and experience more SAEs. In this setting, a MELD score ≥18 may help clinicians to identify those patients with a higher risk of complications and to individualize treatment decisions. This article is protected by copyright. All rights reserved.

  8. EXPERIENCE OF ORNITHINE ASPARTATE (HEPA-MERZ AND PROBIOTICS BIOFLORUM FORTE IN THE TREATMENT OF NON-SEVERE FORMS OF ALCOHOLIC AND NON-ALCOHOLIC FATTY LIVER DISEASE

    Directory of Open Access Journals (Sweden)

    L. Yu. Ilchenko

    2016-01-01

    Full Text Available Aim: to evaluate the efficacy and tolerability of ornithine aspartate, probiotic Bioflorum Forte and their combination with steatosis and steatohepatitis in patients  with alcohol and non-alcoholic  fatty  liver disease. Materials and methods.  An open, randomized,  comparative  clinical study, which included 30 outpatients and inpatients with a diagnosis of steatosis, steatohepatitis. We analyzed the clinical symptoms, functional state of the liver. With the help of questionnaires  (Grids LeGo and post intoxication alcohol syndrome have established the presence of chronic alcohol intoxication. Test transmissions of numbers used to characterize the cognitive function, as well as detection  of minimal hepatic encephalopathy. Quality of life was assessed by questionnaire for patients with chronic liver disease — CLDQ (The chronic liver disease questionnaire. The duration of treatment was4 weeks. Results: all three treatment regimens have demonstrated therapeutic  efficacy: clinical improvement, recovery of liver function and results in cognitive function. When combined therapy also produced a significant improvement  in patients’ quality of life. It is shown that  the safety and tolerability of the means employed, adverse events were not reported. Conclusion: the results obtained allow us to recommend the use of ornithine aspartate (Hepa-Merz, both as monotherapy and as part of complex therapy of steatosis,  steatohepatitis with probiotic Bioflorum Forte in patients with alcoholic and non-alcoholic fatty liver disease.

  9. Oriented Fiber Filter Media

    Directory of Open Access Journals (Sweden)

    R. Bharadwaj

    2008-06-01

    Full Text Available 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 thick layered media can improve performance by about 40%. The results also show the improved performance is not monotonically correlated to the average fiber angle of the medium.

  10. 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

  11. An aperiodic phenomenon of the unscented Kalman filter in filtering noisy chaotic signals

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A non-periodic oscillatory behavior of the unscented Kalman filter (UKF) when used to filter noisy contaminated chaotic signals is reported. We show both theoretically and experimentally that the gain of the UKF may not converge or diverge but oscillate aperiodically. More precisely, when a nonlinear system is periodic, the Kalman gain and error covariance of the UKF converge to zero. However, when the system being considered is chaotic, the Kalman gain either converges to a fixed point with a magnitude larger than zero or oscillates aperiodically.

  12. Filter holder and gasket assembly for candle or tube filters

    Science.gov (United States)

    Lippert, Thomas Edwin; Alvin, Mary Anne; Bruck, Gerald Joseph; Smeltzer, Eugene E.

    1999-03-02

    A filter holder and gasket assembly for holding a candle filter element within a hot gas cleanup system pressure vessel. The filter holder and gasket assembly includes a filter housing, an annular spacer ring securely attached within the filter housing, a gasket sock, a top gasket, a middle gasket and a cast nut.

  13. Microbial Contamination of Ice Machines Is Mediated by Activated Charcoal Filtration Systems in a City Hospital.

    Science.gov (United States)

    Yorioka, Katsuhiro; Oie, Shigeharu; Hayashi, Koji; Kimoto, Hiroo; Furukawa, Hiroyuki

    2016-06-01

    Although microbial contamination of ice machines has been reported, no previous study has addressed microbial contamination of ice produced by machines equipped with activated charcoal (AC) filters in hospitals. The aim of this study was to provide clinical data for evaluating AC filters to prevent microbial contamination of ice. We compared microbial contamination in ice samples produced by machines with (n = 20) and without an AC filter (n = 40) in Shunan City Shinnanyo Municipal Hospital. All samples from the ice machine equipped with an AC filter contained 10-116 CFUs/g of glucose nonfermenting gram-negative bacteria such as Pseudomonas aeruginosa and Chryseobacterium meningosepticum. No microorganisms were detected in samples from ice machines without AC filters. After the AC filter was removed from the ice machine that tested positive for Gram-negative bacteria, the ice was resampled (n = 20). Analysis found no contaminants. Ice machines equipped with AC filters pose a serious risk factor for ice contamination. New filter-use guidelines and regulations on bacterial detection limits to prevent contamination of ice in healthcare facilities are necessary.

  14. 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 computin

  15. 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.

  16. 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...

  17. Bacteria survival probability in bactericidal filter paper.

    Science.gov (United States)

    Mansur-Azzam, Nura; Hosseinidoust, Zeinab; Woo, Su Gyeong; Vyhnalkova, Renata; Eisenberg, Adi; van de Ven, Theo G M

    2014-05-01

    Bactericidal filter papers offer the simplicity of gravity filtration to simultaneously eradicate microbial contaminants and particulates. We previously detailed the development of biocidal block copolymer micelles that could be immobilized on a filter paper to actively eradicate bacteria. Despite the many advantages offered by this system, its widespread use is hindered by its unknown mechanism of action which can result in non-reproducible outcomes. In this work, we sought to investigate the mechanism by which a certain percentage of Escherichia coli cells survived when passing through the bactericidal filter paper. Through the process of elimination, the possibility that the bacterial survival probability was controlled by the initial bacterial load or the existence of resistant sub-populations of E. coli was dismissed. It was observed that increasing the thickness or the number of layers of the filter significantly decreased bacterial survival probability for the biocidal filter paper but did not affect the efficiency of the blank filter paper (no biocide). The survival probability of bacteria passing through the antibacterial filter paper appeared to depend strongly on the number of collision between each bacterium and the biocide-loaded micelles. It was thus hypothesized that during each collision a certain number of biocide molecules were directly transferred from the hydrophobic core of the micelle to the bacterial lipid bilayer membrane. Therefore, each bacterium must encounter a certain number of collisions to take up enough biocide to kill the cell and cells that do not undergo the threshold number of collisions are expected to survive. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. 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.)

  19. Weighted guided image filtering.

    Science.gov (United States)

    Li, Zhengguo; Zheng, Jinghong; Zhu, Zijian; Yao, Wei; Wu, Shiqian

    2015-01-01

    It is known that local filtering-based edge preserving smoothing techniques suffer from halo artifacts. In this paper, a weighted guided image filter (WGIF) is introduced by incorporating an edge-aware weighting into an existing guided image filter (GIF) to address the problem. The WGIF inherits advantages of both global and local smoothing filters in the sense that: 1) the complexity of the WGIF is O(N) for an image with N pixels, which is same as the GIF and 2) the WGIF can avoid halo artifacts like the existing global smoothing filters. The WGIF is applied for single image detail enhancement, single image haze removal, and fusion of differently exposed images. Experimental results show that the resultant algorithms produce images with better visual quality and at the same time halo artifacts can be reduced/avoided from appearing in the final images with negligible increment on running times.

  20. Robustifying Vector Median Filter

    Directory of Open Access Journals (Sweden)

    Valentín Gregori

    2011-08-01

    Full Text Available This paper describes two methods for impulse noise reduction in colour images that outperform the vector median filter from the noise reduction capability point of view. Both methods work by determining first the vector median in a given filtering window. Then, the use of complimentary information from componentwise analysis allows to build robust outputs from more reliable components. The correlation among the colour channels is taken into account in the processing and, as a result, a more robust filter able to process colour images without introducing colour artifacts is obtained. Experimental results show that the images filtered with the proposed method contain less noisy pixels than those obtained through the vector median filter. Objective measures demonstrate the goodness of the achieved improvement.

  1. Filter cake breaker systems

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Marcelo H.F. [Poland Quimica Ltda., Duque de Caxias, RJ (Brazil)

    2004-07-01

    Drilling fluids filter cakes are based on a combination of properly graded dispersed particles and polysaccharide polymers. High efficiency filter cakes are formed by these combination , and their formation on wellbore walls during the drilling process has, among other roles, the task of protecting the formation from instantaneous or accumulative invasion of drilling fluid filtrate, granting stability to well and production zones. Filter cake minimizes contact between drilling fluid filtrate and water, hydrocarbons and clay existent in formations. The uniform removal of the filter cake from the entire interval is a critical factor of the completion process. The main methods used to breaking filter cake are classified into two groups, external or internal, according to their removal mechanism. The aim of this work is the presentation of these mechanisms as well their efficiency. (author)

  2. Naive Bayesian for Email Filtering

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The paper presents a method of email filter based on Naive Bayesian theory that can effectively filter junk mail and illegal mail. Furthermore, the keys of implementation are discussed in detail. The filtering model is obtained from training set of email. The filtering can be done without the users specification of filtering rules.

  3. Recent Advances on Endocrine Disrupting Effects of UV Filters

    Directory of Open Access Journals (Sweden)

    Jiaying Wang

    2016-08-01

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

  4. High-Q Bandpass Comb Filter for Mains Interference Extraction

    Directory of Open Access Journals (Sweden)

    Neycheva T.

    2009-12-01

    Full Text Available This paper presents a simple digital high-Q bandpass comb filter for power-line (PL or other periodical interference extraction. The filter concept relies on a correlated signal average resulting in alternating constructive and destructive spectrum interference i.e. the so-called comb frequency response. The presented filter is evaluated by Matlab simulations with real ECG signal contaminated with low amplitude PL interference. The made simulations show that this filter accurately extract the PL interference. It has high-Q notches only at PL odd harmonics and is appropriate for extraction of any kind of odd harmonic interference including rectangular shape. The filter is suitable for real-time operation with popular low-cost microcontrollers.

  5. How gradients in porosity can make a better filter

    Science.gov (United States)

    Griffiths, Ian; Bruna, Maria; Dalwadi, Mohit

    2015-11-01

    Depth filters are a common device for removing contaminants from fluid. Porosity-graded filters, whose porosities decrease with depth, have been shown experimentally to offer improved filtration efficiency over filters with uniform porosity, by allowing contaminants to be trapped more evenly within the filter media. However, experiments are unable to probe the microscopic behavior, and so the underlying mechanisms that are responsible for this improved filtration are unclear. We use homogenization theory to derive a macroscopic model for the fluid flow and particle trapping within a porosity-graded depth filter. We find that gradients in porosity induce a macroscale particle advection in the direction of reducing porosity and show how particle trapping is more evenly spread through the filter for a decreasing porosity compared with a uniform porosity. By quantifying the removal rate, we show how a given operating regime can be fine-tuned to improve filter efficiency. The talk is accompanied by an online demonstration of MEMFI, a software package in which audience members may explore for themselves the effect of porosity gradients in user-specified operating regimes.

  6. 油田废弃核桃壳滤料的污染物分析及其对土壤的影响研究%Contaminations of Waste Walnut-Shell Filtering Materials and the Impact on Soil Environment in Oil Field

    Institute of Scientific and Technical Information of China (English)

    朱艳吉; 匡丽; 王宝辉; 汪怀远

    2012-01-01

    核桃壳滤料广泛应用于油田污水处理,每年因此产生大量的废弃核桃壳滤料,由于将其露天堆砌在地面上,滤料上的污染物在降水、风力、地表径流等的作用下发生迁移,直接影响到堆砌场地周边的土壤、大气、水源的质量.采用标准方法对油田废弃核桃壳滤料上的污染物组成进行分析的结果表明,主要污染物为原油、CaCO3和Cd2+、Pb2+重金属离子,污染物总含量较高,与原油组成相比,废弃核桃壳滤料上的芳烃含量增加较多,饱和烃和胶质有所减少.借助一维对流-弥散方程建立了模拟石油类污染物在土壤中迁移转化规律的数学模型,通过室内土柱实验确定模型参数,同时验证模型的准确性.将实验及模拟的结果相结合可知,该模型可以用来模拟石油类污染物在土壤中的迁移规律,符合y=y0+A1exp(-x/t1 )+A2exp(-x/t2)规律.研究结果为油田废弃滤料对土壤环境的影响及治理提供了参考.%Due to high surface area, excellent adsorption and desorption, and low cost, walnut shell is widely used for filtering materials of the produced water in oil field. A lot of waste walnut-shell filtering materials are discharged in the oil production. The waste walnut shell filter is generally discarded on the soil. So, it is obvious that effect of the pollutions from the waste walnut shell on the soil, atmosphere, and water by the way of precipitation, wind and surface water. In this paper, the contaminations of waste walnut shell filter from oil field were analysed by national standard methods. It was found that the content of crude oil, CaCO3, Cd2+ and Pb2+ reached 17.55%, 1.51%, 1.33 mg·kg‐1 and 317.3 mg·kg‐1, respectively, and the high COD origins from pollutions. Compared with the average crude oil, the aroma fraction was concentrated in the waste walnut shell while the saturated hydrocarbon and colloid composition was decreased. The reason was that the aroma was stable

  7. Interactions of endosulfan and methoxychlor involving CYP3A4 and CYP2B6 in human HepaRG cells.

    Science.gov (United States)

    Savary, Camille C; Jossé, Rozenn; Bruyère, Arnaud; Guillet, Fabrice; Robin, Marie-Anne; Guillouzo, André

    2014-08-01

    Humans are usually exposed to several pesticides simultaneously; consequently, combined actions between pesticides themselves or between pesticides and other chemicals need to be addressed in the risk assessment. Many pesticides are efficient activators of pregnane X receptor (PXR) and/or constitutive androstane receptor (CAR), two major nuclear receptors that are also activated by other substrates. In the present work, we searched for interactions between endosulfan and methoxychlor, two organochlorine pesticides whose major routes of metabolism involve CAR- and PXR-regulated CYP3A4 and CYP2B6, and whose mechanisms of action in humans remain poorly understood. For this purpose, HepaRG cells were treated with both pesticides separately or in mixture for 24 hours or 2 weeks at concentrations relevant to human exposure levels. In combination they exerted synergistic cytotoxic effects. Whatever the duration of treatment, both compounds increased CYP3A4 and CYP2B6 mRNA levels while differently affecting their corresponding activities. Endosulfan exerted a direct reversible inhibition of CYP3A4 activity that was confirmed in human liver microsomes. By contrast, methoxychlor induced this activity. The effects of the mixture on CYP3A4 activity were equal to the sum of those of each individual compound, suggesting an additive effect of each pesticide. Despite CYP2B6 activity being unchanged and increased with endosulfan and methoxychlor, respectively, no change was observed with their mixture, supporting an antagonistic effect. Altogether, our data suggest that CAR and PXR activators endosulfan and methoxychlor can interact together and with other exogenous substrates in human hepatocytes. Their effects on CYP3A4 and CYP2B6 activities could have important consequences if extrapolated to the in vivo situation.

  8. 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...... filter and the DD2 filter. It also contains functions for Unscented Kalman filters as well as several versions of particle filters. The toolbox requires MATLAB version 7, but no additional toolboxes are required....

  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. 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...... in the expected sense. The second scheme is a Las Vegas algorithm using filtering triggers: Its effectiveness is the same as enforcing are consistency after every domain event, while in the expected case it is faster by a factor of m/n, where n and m are, respectively, the number of nodes and edges...

  12. A Comparison of IIR and Wavelet Filtering for Noise Reduction of the ECG.

    Science.gov (United States)

    Sørensen, Js; Johannesen, L; Grove, Usl; Lundhus, K; Couderc, J-P; Graff, C

    2010-09-26

    This study compares the ability to preserve information and reduce noise contaminants on the ECG for five wavelet filters and three IIR filters. Two 3-lead Holter ECGs were used. White Gaussian Noise was added to the first ECG in increments of 10% coverage. The second ECG contained alternating muscle transients and noise-free segments. Computation times and SNR improvements for different noise coverages were calculated and compared. RMS errors were calculated from noise-free segments on the ECG with transient muscle noise. Wavelet filters improved SNR more than IIR filters when the signal coverage was more than 50% noise. In contrast, the computation times were shorter for IIR filters (6 s) than for wavelet filters (88 s). On the ECG with transient muscle noise there was a trade-off in performance between wavelet and IIR filtering. In a clinical setting where the amount of noise is unknown, using IIR filters appears to be preferred for consistent performance.

  13. Air Filter Simulation by Geodict

    Institute of Scientific and Technical Information of China (English)

    WANG Xin-peng; Kitai Kim; Changhwan Lee; Jooyong Kim

    2006-01-01

    In this paper, we discussed the relationship of filter efficiency and pressure drop with the porosity, fiber diameter and filter thickness by Geodict. We found that filter efficiency will increase when filter porosity and fiber diameter decreasing or filter thickness increasing. And the pressure drop has a linear relationship with filter thickness and non-linear relationship with filter porosity and fiber diameter. We also compared the simulation results with the real test results by TSI 3160. Although there are some differences, I think Geodict can be used to predict filter efficiency and pressure drop.

  14. Experimental comparison of point-of-use filters for drinking water ultrafiltration.

    Science.gov (United States)

    Totaro, M; Valentini, P; Casini, B; Miccoli, M; Costa, A L; Baggiani, A

    2017-06-01

    Waterborne pathogens such as Pseudomonas spp. and Legionella spp. may persist in hospital water networks despite chemical disinfection. Point-of-use filtration represents a physical control measure that can be applied in high-risk areas to contain the exposure to such pathogens. New technologies have enabled an extension of filters' lifetimes and have made available faucet hollow-fibre filters for water ultrafiltration. To compare point-of-use filters applied to cold water within their period of validity. Faucet hollow-fibre filters (filter A), shower hollow-fibre filters (filter B) and faucet membrane filters (filter C) were contaminated in two different sets of tests with standard bacterial strains (Pseudomonas aeruginosa DSM 939 and Brevundimonas diminuta ATCC 19146) and installed at points-of-use. Every day, from each faucet, 100 L of water was flushed. Before and after flushing, 250 mL of water was collected and analysed for microbiology. There was a high capacity of microbial retention from filter C; filter B released only low Brevundimonas spp. counts; filter A showed poor retention of both micro-organisms. Hollow-fibre filters did not show good micro-organism retention. All point-of-use filters require an appropriate maintenance of structural parameters to ensure their efficiency. Copyright © 2016 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  15. Methoxychlor suppresses the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-inducible CYP1A1 expression in murine Hepa-1c1c7 cells.

    Science.gov (United States)

    Han, Eun Hee; Jeong, Tae Cheon; Jeong, Hye Gwang

    2007-08-01

    Methoxychlor (MXC) is a pesticide that was developed as a replacement for dichlorodiphenyltrichloroethane (DDT). The influence of MXC on CYP1A1 expression or the functions of mouse hepatoma Hepa-1clc7 remain unclear. Cultured Hepa-1c1c7 cells were treated with MXC with or without 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to assess the role of MXC on CYP1A1 expression. MXC alone did not affect CYP1A1-specific 7-ethoxyresorufin O-deethylase (EROD) activity. In contrast, TCDD-inducible EROD activities were markedly reduced upon concomitant treatment with TCDD and MXC in a concentration-dependent manner. Treatment with ICI 182.780, an estrogen-receptor antagonist, did not affect the suppressive effects of MXC on TCDD-inducible EROD activity. TCDD-inducible CYP1A1 mRNA levels were markedly suppressed upon treatment with TCDD and MXC, and this is consistent with their effects on EROD activity. A transient transfection assay using dioxin-response element (DRE)-linked luciferase and an electrophoretic mobility shift assay revealed that MXC reduced the transformation of the aryl hydrocarbons (Ah) receptor to a form capable of specifically binding to the DRE sequence in the promoter region of the CYP1A1 gene. These results suggest that the downregulation of CYP1A1 gene expression by MXC in Hepa-1c1c7 cells might be an antagonism of the DRE binding potential of the nuclear Ah receptor but is not mediated through the estradiol receptor.

  16. Updating the OMERACT filter

    DEFF Research Database (Denmark)

    Kirwan, John R; Boers, Maarten; Hewlett, Sarah

    2014-01-01

    OBJECTIVE: The Outcome Measures in Rheumatology (OMERACT) Filter provides guidelines for the development and validation of outcome measures for use in clinical research. The "Truth" section of the OMERACT Filter presupposes an explicit framework for identifying the relevant core outcomes that are......OBJECTIVE: The Outcome Measures in Rheumatology (OMERACT) Filter provides guidelines for the development and validation of outcome measures for use in clinical research. The "Truth" section of the OMERACT Filter presupposes an explicit framework for identifying the relevant core outcomes...... that are universal to all studies of the effects of intervention effects. There is no published outline for instrument choice or development that is aimed at measuring outcome, was derived from broad consensus over its underlying philosophy, or includes a structured and documented critique. Therefore, a new proposal...

  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. 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.

  19. Updating the OMERACT filter

    DEFF Research Database (Denmark)

    Tugwell, Peter; Boers, Maarten; D'Agostino, Maria-Antonietta

    2014-01-01

    OBJECTIVE: The Outcome Measures in Rheumatology (OMERACT) Filter provides guidelines for the development and validation of outcome measures for use in clinical research. The "Truth" section of the OMERACT Filter requires that criteria be met to demonstrate that the outcome instrument meets...... the criteria for content, face, and construct validity. METHODS: Discussion groups critically reviewed a variety of ways in which case studies of current OMERACT Working Groups complied with the Truth component of the Filter and what issues remained to be resolved. RESULTS: The case studies showed...... that there is broad agreement on criteria for meeting the Truth criteria through demonstration of content, face, and construct validity; however, several issues were identified that the Filter Working Group will need to address. CONCLUSION: These issues will require resolution to reach consensus on how Truth...

  20. 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.

  1. 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).

  2. Cryogenic coaxial microwave filters

    CERN Document Server

    Tancredi, G; Meeson, P J

    2014-01-01

    At millikelvin temperatures the careful filtering of electromagnetic radiation, especially in the microwave regime, is critical for controlling the electromagnetic environment for experiments in fields such as solid-state quantum information processing and quantum metrology. We present a design for a filter consisting of small diameter dissipative coaxial cables that is straightforward to construct and provides a quantitatively predictable attenuation spectrum. We describe the fabrication process and demonstrate that the performance of the filters is in good agreement with theoretical modelling. We further perform an indicative test of the performance of the filters by making current-voltage measurements of small, underdamped Josephson Junctions at 15 mK and we present the results.

  3. Demonstration of a Filter Cart for NOx Removal from Ground Support Equipment.

    Science.gov (United States)

    2007-11-02

    emissions. The filter cart was designed to control emissions of NOx, particulate, and unburned hydrocarbons ( UHCs ) from mobile diesel generators. It uses a...rows of activated carbon (AC) filters to adsorb NOx and UHCs . A separate stand-alone system is used to desorb and destroy the contaminants adsorbed

  4. Dual-color fluorescence imaging to monitor CYP3A4 and CYP3A7 expression in human hepatic carcinoma HepG2 and HepaRG cells.

    Directory of Open Access Journals (Sweden)

    Saori Tsuji

    Full Text Available Human adult hepatocytes expressing CYP3A4, a major cytochrome P450 enzyme, are required for cell-based assays to evaluate the potential risk of drug-drug interactions caused by transcriptional induction of P450 enzymes in early-phase drug discovery and development. However, CYP3A7 is preferentially expressed in premature hepatoblasts and major hepatic carcinoma cell lines. The human hepatocellular carcinoma cell line HepaRG possesses a high self-renewal capacity and can differentiate into hepatic cells similar to human adult hepatocytes in vitro. Transgenic HepaRG cells, in which the expression of fluorescent reporters is regulated by 35 kb regulatory elements of CYP3A4, have a distinct advantage over human hepatocytes isolated by collagenase perfusion, which are unstable in culture. Thus, we created transgenic HepaRG and HepG2 cells by replacing the protein-coding regions of human CYP3A4 and CYP3A7 with enhanced green fluorescent protein (EGFP and DsRed reporters, respectively, in a bacterial artificial chromosome vector that included whole regulatory elements. The intensity of DsRed fluorescence was initially high during the proliferation of transgenic HepaRG cells. However, most EGFP-positive cells were derived from those in which DsRed fluorescence was extinguished. Comparative analyses in these transgenic clones showed that changes in the total fluorescence intensity of EGFP reflected fold changes in the mRNA level of endogenous CYP3A4. Moreover, CYP3A4 induction was monitored by the increase in EGFP fluorescence. Thus, this assay provides a real-time evaluation system for quality assurance of hepatic differentiation into CYP3A4-expressing cells, unfavourable CYP3A4 induction, and fluorescence-activated cell sorting-mediated enrichment of CYP3A4-expressing hepatocytes based on the total fluorescence intensities of fluorescent reporters, without the need for many time-consuming steps.

  5. Holographic interference filters

    Science.gov (United States)

    Diehl, Damon W.

    Holographic mirrors have wavelength-selection properties and thus qualify as a class of interference filters. Two theoretical methods for analyzing such structures are developed. The first method uses Hill's matrix method to yield closed-forms solutions in terms of the Floquet-Bloch waves within a periodic structure. A process is developed for implementing this solution method on a computer, using sparse-matrix memory allocation, numerical root-finding algorithms, and inverse-iteration techniques. It is demonstrated that Hill's matrix method is valid for the analysis of finite and multi-periodic problems. The second method of theoretical analysis is a transfer-matrix technique, which is herein termed thin-film decomposition. It is shown that the two methods of solution yield results that differ by, at worst, a fraction of a percent. Using both calculation techniques, a number of example problems are explored. Of key importance is the construction of a set of curves that are useful for the design and characterization of holographic interference filters. In addition to the theoretical development, methods are presented for the fabrication of holographic interference filters using DuPont HRF-800X001 photopolymer. Central to the exposure system is a frequency-stabilized, tunable dye laser. The types of filters fabricated include single-tone reflection filters, two types of multitone reflection filters, and reflection filters for infrared wavelengths. These filters feature index profiles that are not easily attainable through other fabrication methods. As a supplement to the body of the dissertation, the computer algorithms developed to implement Hill's matrix method and thin-film decomposition are also included as an appendix. Further appendices provide more information on Floquet's theorem and Hill's matrix method. A final appendix presents a design for an infrared laser spectrophotometer.

  6. The Endogenous Kalman Filter

    OpenAIRE

    Brad Baxter; Liam Graham; Stephen Wright

    2007-01-01

    We relax the assumption of full information that underlies most dynamic general equilibrium models, and instead assume agents optimally form estimates of the states from an incomplete information set. We derive a version of the Kalman filter that is endogenous to agents' optimising decisions, and state conditions for its convergence. We show the (restrictive) conditions under which the endogenous Kalman filter will at least asymptotically reveal the true states. In general we show that incomp...

  7. 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.

  8. Mining dust filter. Bergbaustaubfilter

    Energy Technology Data Exchange (ETDEWEB)

    Igelbuescher, H.; Hoelter, H.

    1988-12-28

    A dust filter for application underground, whose casing is designed as a transportable unit combinable with further casings and fitted with removable filter pockets. These filter pockets have a frame which seals towards the casing and with the lattices on which the filter cloth is stretched and with spacers holding the said lattices at a distance. Each casing as such has inspection ports that are operationable optionally on either side, and clean and crude gas channels on its upper side. The ends of these channels have coupleable head pieces, so that connection is made easy when casings are arranged in a line. Each crude gas channel is connected to the inside of the casing by means of perforations in the floor of said channel, whereas the clean gas channel, for its part, is in connection with the inside of the casing by means of a channel on the head side of the casing. It is thus possible to create a dust filter having practically any desired output by arranging individual modules in line, in which connection each individual module is reliably transportable on the facilities available below ground, as pre-fabricated above ground. Stable support of the sides of the filter cloths is ensured by the lattice that consists of reciprocally cranked longitudinal and transverse wires. 10 figs.

  9. Effectiveness of adverse effects search filters: drugs versus medical devices

    Directory of Open Access Journals (Sweden)

    Kelly Farrah, MLIS, AHIP

    2016-09-01

    Full Text Available Objective: The study tested the performance of adverse effects search filters when searching for safety information on medical devices, procedures, and diagnostic tests in MEDLINE and Embase. Methods: The sensitivity of 3 filters was determined using a sample of 631 references from 131 rapid reviews related to the safety of health technologies. The references were divided into 2 sets by type of intervention: drugs and nondrug health technologies. Keyword and indexing analysis were performed on references from the nondrug testing set that 1 or more of the filters did not retrieve. Results: For all 3 filters, sensitivity was lower for nondrug health technologies (ranging from 53%– 87% than for drugs (88%–93% in both databases. When tested on the nondrug health technologies set, sensitivity was lower in Embase (ranging from 53%–81% than in MEDLINE (67%–87% for all filters. Of the nondrug records that 1 or more of the filters missed, 39% of the missed MEDLINE records and 18% of the missed Embase records did not contain any indexing terms related to adverse events. Analyzing the titles and abstracts of nondrug records that were missed by any 1 filter, the most commonly used keywords related to adverse effects were: risk, complications, mortality, contamination, hemorrhage, and failure. Conclusions: In this study, adverse effects filters were less effective at finding information about the safety of medical devices, procedures, and tests compared to information about the safety of drugs.

  10. Fractional vortex dipole phase filter

    Science.gov (United States)

    Sharma, Manoj Kumar; Joseph, Joby; Senthilkumaran, Paramasivam

    2014-10-01

    In spatial filtering experiments, the use of vortex phase filters plays an important role in realizing isotropic edge enhancement. In this paper, we report the use of a vortex dipole phase filter in spatial filtering. A dipole made of fractional vortices is used, and its filtering characteristics are studied. It is observed that the filter performance can be tuned by varying the distance of separation between the vortices of the dipole to achieve better contrast and output noise suppression, and when this distance tends to infinity, the filter performs like a 1-D Hilbert mask. Experimental and simulation results are presented.

  11. 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

  12. An IIR median hybrid filter

    Science.gov (United States)

    Bauer, Peter H.; Sartori, Michael A.; Bryden, Timothy M.

    1992-01-01

    A new class of nonlinear filters, the so-called class of multidirectional infinite impulse response median hybrid filters, is presented and analyzed. The input signal is processed twice using a linear shift-invariant infinite impulse response filtering module: once with normal causality and a second time with inverted causality. The final output of the MIMH filter is the median of the two-directional outputs and the original input signal. Thus, the MIMH filter is a concatenation of linear filtering and nonlinear filtering (a median filtering module). Because of this unique scheme, the MIMH filter possesses many desirable properties which are both proven and analyzed (including impulse removal, step preservation, and noise suppression). A comparison to other existing median type filters is also provided.

  13. Two-zone pupil filters

    Science.gov (United States)

    Sheppard, Colin J. R.; Campos, Juan; Escalera, Juan C.; Ledesma, Silvia

    2008-03-01

    The performance of pupil filters consisting of two zones each of constant complex amplitude transmittance is investigated. For filters where the transmittance is real, different classes of potentially useful filter are identified and optimized. These include leaky filters with an inner zone of low amplitude transmittance, pure phase filters with phase change of π, and equal area filters. The first of these minimizes the relative power in the outer rings for a given axial resolution, the second maximizes the Strehl ratio for a given transverse resolution, and the third minimizes the relative power in the outer rings for a given transverse resolution. Complex filters can give an axially shifted maximum in intensity: the performance parameters calculated relative to the true focus are investigated for some different classes of filter, but filters with phase change not equal to π are found to give inferior performance to the real value filters.

  14. Remotely serviced filter and housing

    Science.gov (United States)

    Ross, M.J.; Zaladonis, L.A.

    1987-07-22

    A filter system for a hot cell comprises a housing adapted for input of air or other gas to be filtered, flow of the air through a filter element, and exit of filtered air. The housing is tapered at the top to make it easy to insert a filter cartridge holds the filter element while the air or other gas is passed through the filter element. Captive bolts in trunnion nuts are readily operated by electromechanical manipulators operating power wrenches to secure and release the filter cartridge. The filter cartridge is adapted to make it easy to change a filter element by using a master-slave manipulator at a shielded window station. 6 figs.

  15. 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.

  16. 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.

  17. NOTCH FILTER USING SIMULATED INDUCTOR

    Directory of Open Access Journals (Sweden)

    D.SUSAN,

    2011-06-01

    Full Text Available The design of analog filters at low frequencies is not possible because the size of inductors becomes very large. In such cases, the simulated inductors using operational amplifiers are used. This paper deals with the implementation of notch filter using band pass filter which uses simulated inductor where the direct implementation of notch filter using simulated inductor is not possible because of floating inductor. The design of notch filter and the simulation done in PSPICE is presented.

  18. Improved directional-distance filter

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This paper proposes a new spatial-distance weighting function.By combining the weighting function and the traditional directional-distance filter (DDF) in a novel way,a new vector filter-the adaptive distance-weighted directional-distance filter (ADWDDF)-is presented.The experimental results show that the proposed solution provides better filtering performance and preserves better image chromaticity and edge or detail information compared with the traditional DDF and some other typical vector filters.

  19. Modeling the Performance of Biological Rapid Sand Filters Used to Remove Ammonium, Iron, and Manganese From Drinking Water

    DEFF Research Database (Denmark)

    Lee, Carson; Albrechtsen, Hans-Jørgen; Smets, Barth F.;

    filter management to performance . Biological rapid sand filters are used for the dual purpose of particle removal (including microorganisms) and contaminant removal through biological activity on the filter media. For drinking water treatment in the United States, biological filters use granular......Although biological rapid sand filters are a well established technology for treating drinking water, there is still a lack of scientific understanding of the processes controlling their performance. For example, the distribution and role of microorganisms in contaminant removal in the filter has...... for chlorine addition following treatment. Under the normal conditions found in many water treatment plants, reduced iron can be oxidized through aeration and the precipitates can be captured by the filter media. Ammonium and manganese can be removed biologically. This research uses both pilot and full scale...

  20. 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.

  1. 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.

  2. 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...

  3. Comparison of sand-based water filters for point-of-use arsenic removal in China.

    Science.gov (United States)

    Smith, Kate; Li, Zhenyu; Chen, Bohan; Liang, Honggang; Zhang, Xinyi; Xu, Ruifei; Li, Zhilin; Dai, Huanfang; Wei, Caijie; Liu, Shuming

    2017-02-01

    Contamination of groundwater wells by arsenic is a major problem in China. This study compared arsenic removal efficiency of five sand-based point-of-use filters with the aim of selecting the most effective filter for use in a village in Shanxi province, where the main groundwater source had arsenic concentration >200 μg/L. A biosand filter, two arsenic biosand filters, a SONO-style filter and a version of the biosand filter with nails embedded in the sand were tested. The biosand filter with embedded nails was the most consistent and effective under the study conditions, likely due to increased contact time between water and nails and sustained corrosion. Effluent arsenic was below China's standard of 50 μg/L for more than six months after construction. The removal rate averaged 92% and was never below 86%. In comparison, arsenic removal for the nail-free biosand filter was never higher than 53% and declined with time. The arsenic biosand filter, in which nails sit in a diffuser basin above the sand, performed better but effluent arsenic almost always exceeded the standard. This highlights the positive impact on arsenic removal of embedding nails within the top layer of biosand filter sand and the promise of this low-cost filtration method for rural areas affected by arsenic contamination. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. 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...

  5. 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...

  6. Physics-based prognostic modelling of filter clogging phenomena

    Science.gov (United States)

    Eker, Omer F.; Camci, Fatih; Jennions, Ian K.

    2016-06-01

    In industry, contaminant filtration is a common process to achieve a desired level of purification, since contaminants in liquids such as fuel may lead to performance drop and rapid wear propagation. Generally, clogging of filter phenomena is the primary failure mode leading to the replacement or cleansing of filter. Cascading failures and weak performance of the system are the unfortunate outcomes due to a clogged filter. Even though filtration and clogging phenomena and their effects of several observable parameters have been studied for quite some time in the literature, progression of clogging and its use for prognostics purposes have not been addressed yet. In this work, a physics based clogging progression model is presented. The proposed model that bases on a well-known pressure drop equation is able to model three phases of the clogging phenomena, last of which has not been modelled in the literature yet. In addition, the presented model is integrated with particle filters to predict the future clogging levels and to estimate the remaining useful life of fuel filters. The presented model has been implemented on the data collected from an experimental rig in the lab environment. In the rig, pressure drop across the filter, flow rate, and filter mesh images are recorded throughout the accelerated degradation experiments. The presented physics based model has been applied to the data obtained from the rig. The remaining useful lives of the filters used in the experimental rig have been reported in the paper. The results show that the presented methodology provides significantly accurate and precise prognostic results.

  7. Statistically-Efficient Filtering in Impulsive Environments: Weighted Myriad Filters

    Directory of Open Access Journals (Sweden)

    Gonzalez Juan G

    2002-01-01

    Full Text Available Linear filtering theory has been largely motivated by the characteristics of Gaussian signals. In the same manner, the proposed Myriad Filtering methods are motivated by the need for a flexible filter class with high statistical efficiency in non-Gaussian impulsive environments that can appear in practice. Myriad filters have a solid theoretical basis, are inherently more powerful than median filters, and are very general, subsuming traditional linear FIR filters. The foundation of the proposed filtering algorithms lies in the definition of the myriad as a tunable estimator of location derived from the theory of robust statistics. We prove several fundamental properties of this estimator and show its optimality in practical impulsive models such as the -stable and generalized- . We then extend the myriad estimation framework to allow the use of weights. In the same way as linear FIR filters become a powerful generalization of the mean filter, filters based on running myriads reach all of their potential when a weighting scheme is utilized. We derive the "normal" equations for the optimal myriad filter, and introduce a suboptimal methodology for filter tuning and design. The strong potential of myriad filtering and estimation in impulsive environments is illustrated with several examples.

  8. Domain wall filters

    CERN Document Server

    Bär, O; Neuberger, H; Witzel, O; Baer, Oliver; Narayanan, Rajamani; Neuberger, Herbert; Witzel, Oliver

    2007-01-01

    We propose using the extra dimension separating the domain walls carrying lattice quarks of opposite handedness to gradually filter out the ultraviolet fluctuations of the gauge fields that are felt by the fermionic excitations living in the bulk. This generalization of the homogeneous domain wall construction has some theoretical features that seem nontrivial.

  9. 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 f

  10. Magnetic-Optical Filter

    CERN Document Server

    Formicola, I; Pinto, C; Cerulo, P

    2007-01-01

    Magnetic-Optical Filter (MOF) is an instrument suited for high precision spectral measurements for its peculiar characteristics. It is employed in Astronomy and in the field of the telecommunications (it is called FADOF there). In this brief paper we summarize its fundamental structure and functioning.

  11. 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.

  12. Ozone decomposing filter

    Science.gov (United States)

    Simandl, Ronald F.; Brown, John D.; Whinnery, Jr., LeRoy L.

    1999-01-01

    In an improved ozone decomposing air filter carbon fibers are held together with a carbonized binder in a perforated structure. The structure is made by combining rayon fibers with gelatin, forming the mixture in a mold, freeze-drying, and vacuum baking.

  13. Spot- Zombie Filtering System

    Directory of Open Access Journals (Sweden)

    Arathy Rajagopal

    2014-01-01

    Full Text Available 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 send the spam messages to the targeted machine by exalting the filters, which causes the increase in false positives and false negatives. We develop an effective spam zombie detection system named SPOT by monitoring outgoing messages of a network. SPOT focuses on the number of outgoing messages that are originated or forwarded by each computer on a network to identify the presence of Zombies. SPOT is designed based on a powerful statistical tool called Sequential Probability Ratio Test, which has bounded false positive and false negative error rates.

  14. Digital hum filtering

    Science.gov (United States)

    Knapp, R.W.; Anderson, N.L.

    1994-01-01

    Data may be overprinted by a steady-state cyclical noise (hum). Steady-state indicates that the noise is invariant with time; its attributes, frequency, amplitude, and phase, do not change with time. Hum recorded on seismic data usually is powerline noise and associated higher harmonics; leakage from full-waveform rectified cathodic protection devices that contain the odd higher harmonics of powerline frequencies; or vibrational noise from mechanical devices. The fundamental frequency of powerline hum may be removed during data acquisition with the use of notch filters. Unfortunately, notch filters do not discriminate signal and noise, attenuating both. They also distort adjacent frequencies by phase shifting. Finally, they attenuate only the fundamental mode of the powerline noise; higher harmonics and frequencies other than that of powerlines are not removed. Digital notch filters, applied during processing, have many of the same problems as analog filters applied in the field. The method described here removes hum of a particular frequency. Hum attributes are measured by discrete Fourier analysis, and the hum is canceled from the data by subtraction. Errors are slight and the result of the presence of (random) noise in the window or asynchrony of the hum and data sampling. Error is minimized by increasing window size or by resampling to a finer interval. Errors affect the degree of hum attenuation, not the signal. The residual is steady-state hum of the same frequency. ?? 1994.

  15. Particle filter based entropy

    NARCIS (Netherlands)

    Boers, Y.; Driessen, Hans; Bagchi, Arunabha; Mandal, Pranab K.

    For many problems in the field of tracking or even the wider area of filtering the a posteriori description of the uncertainty can oftentimes not be described by a simple Gaussian density function. In such situations the characterization of the uncertainty by a mean and a covariance does not capture

  16. Spot- Zombie Filtering System

    Directory of Open Access Journals (Sweden)

    Arathy Rajagopal

    2015-10-01

    Full Text Available 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 send the spam messages to the targeted machine by exalting the filters, which causes the increase in false positives and false negatives. We develop an effective spam zombie detection system named SPOT by monitoring outgoing messages of a network. SPOT focuses on the number of outgoing messages that are originated or forwarded by each computer on a network to identify the presence of Zombies. SPOT is designed based on a powerful statistical tool called Sequential Probability Ratio Test, which has bounded false positive and false negative error rates.

  17. Harvesting contaminants from liquid

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, John T.; Hunter, Scott R.

    2016-05-31

    Disclosed are examples of apparatuses for evaporative purification of a contaminated liquid. In each example, there is a vessel for storing the contaminated fluid. The vessel includes a surface coated with a layer of superhydrophobic material and the surface is at least partially in contact with the contaminated liquid. The contaminants do not adhere to the surface as the purified liquid evaporates, thus allowing the contaminants to be harvested.

  18. Filtered epithermal quasi-monoenergetic neutron beams at research reactor facilities.

    Science.gov (United States)

    Mansy, M S; Bashter, I I; El-Mesiry, M S; Habib, N; Adib, M

    2015-03-01

    Filtered neutron techniques were applied to produce quasi-monoenergetic neutron beams in the energy range of 1.5-133keV at research reactors. A simulation study was performed to characterize the filter components and transmitted beam lines. The filtered beams were characterized in terms of the optimal thickness of the main and additive components. The filtered neutron beams had high purity and intensity, with low contamination from the accompanying thermal emission, fast neutrons and γ-rays. A computer code named "QMNB" was developed in the "MATLAB" programming language to perform the required calculations.

  19. 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...... indicate that IIR filters are the most effective in a number of situations....

  20. Apodized RFI filtering of synthetic aperture radar images

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2014-02-01

    Fine resolution Synthetic Aperture Radar (SAR) systems necessarily require wide bandwidths that often overlap spectrum utilized by other wireless services. These other emitters pose a source of Radio Frequency Interference (RFI) to the SAR echo signals that degrades SAR image quality. Filtering, or excising, the offending spectral contaminants will mitigate the interference, but at a cost of often degrading the SAR image in other ways, notably by raising offensive sidelobe levels. This report proposes borrowing an idea from nonlinear sidelobe apodization techniques to suppress interference without the attendant increase in sidelobe levels. The simple post-processing technique is termed Apodized RFI Filtering (ARF).

  1. Wash water in waterworks: contaminants and process options for reclamation

    Institute of Scientific and Technical Information of China (English)

    C B Chidambara Raj; Tan Ee Kwong; Wong Wai Cheng; Lee Mun Fong; Soh Hoo Tiong; Paul Stefan Klose

    2008-01-01

    Reclamation of clean water from filter backwash water was studied through pilot-scale experiments. The pilot plant consisted of clarification, sand-filtration, and ultrafiltration modules in sequence, with a provision to bypass the sand filter. Clean water that conformed to World Health Organization (WHO) guidelines on Potable Quality was reclaimed. Turbidity, aluminum and iron were found to be critical contaminants in process selection and design. Clarification, followed by sand filtration, was found to be the minimum requirement for recycling filter backwash. However, membrane filtration would enhance reclaimed water quality as the membrane acts as an additional barrier against Giardia and Cryptosporidium.

  2. Development of DWDM Filter Manufacture

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    DWDM technology is developing rapidly. Thin film narrow bandpass filter plays an important role in this field. This article presents some achievements in developing the DWDM narrow bandpass filters and also describes the results achieved by us.

  3. 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 ...

  4. In vitro comparison of epidural bacteria filters permeability and screening scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    Aysin Sener

    2015-12-01

    Full Text Available BACKGROUND AND OBJECTIVES: Epidural catheter bacteria filters are barriers in the patient-controlled analgesia/anaesthesia for preventing contamination at the epidural insertion site. The efficiency of these filters varies according to pore sizes and materials. METHOD: The bacterial adhesion capability of the two filters was measured in vitro experiment. Adhesion capacities for standard Staphylococcus aureus (ATCC 25923 and Pseudomonas aeruginosa (ATCC 27853 strains of the two different filters (Portex and Rusch which have the same pore size were examined. Bacterial suspension of 0.5 Mc Farland was placed in the patient-controlled analgesia pump, was filtered at a speed of 5 mL/h. in continuous infusion for 48 h and accumulated in bottle. The two filters were compared with colony counts of bacteria in the filters and bottles. At the same time, the filters and adhered bacteria were monitored by scanning electron microscope. RESULTS: Electron microscopic examination of filters showed that the Portex filter had a granular and the Rusch filter fibrillary structure. Colony counting from the catheter and bottle showed that both of the filters have significant bacterial adhesion capability (p < 0.001. After the bacteria suspension infusion, colony countings showed that the Portex filter was more efficient (p < 0.001. There was not any difference between S. aureus and P. aeruginosa bacteria adhesion. In the SEM monitoring after the infusion, it was physically shown that the bacteria were adhered efficiently by both of the filters. CONCLUSION: The granular structured filter was found statistically and significantly more successful than the fibrial. Although the pore sizes of the filters were same - of which structural differences shown by SEM were the same - it would not be right to attribute the changes in the efficiencies to only structural differences. Using microbiological and physical proofs with regard to efficiency at the same time has been

  5. Reduction in operatory mercury levels after contamination or amalgam removal.

    Science.gov (United States)

    Ferracane, J L; Engle, J H; Okabe, T; Mitchem, J C

    1994-04-01

    The threshold limit value (TLV) for occupational exposure to mercury can be exceeded in the dental operatory after a contamination event or during certain dental procedures. The objective of this study was to determine the time required for the mercury vapor levels to return to baseline in both non-ventilated and ventilated operatories after they had been contaminated with mercury to the TLV of 0.050 mg/m3; and to evaluate the efficiency of an activated charcoal filtering device for removing mercury vapor. The results showed that even in a poorly ventilated operatory, the mercury vapor level returned to background within 20-30 minutes after a contamination, and within 10-20 minutes when the operatory was ventilated. The filtering device reduced the level of mercury vapor by approximately 25% during a continuous contamination event, but did not clear the operatory faster than normal settling after a limited source contamination. The filter caused a significant reduction in mercury in the breathing zones of the patient and dentist during and after amalgam removal, but did not eliminate the exposure. This study demonstrated the difficulty in contaminating an operatory with mercury vapor and confirmed the limited time mercury remains airborne, presumably due to its density and affinity for surfaces.

  6. 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.

  7. Assessment of ceramic membrane filters

    Energy Technology Data Exchange (ETDEWEB)

    Ahluwalia, R.K.; Geyer, H.K.; Im, K.H. [and others

    1995-08-01

    The objectives of this project include the development of analytical models for evaluating the fluid mechanics of membrane coated, dead-end ceramic filters, and to determine the effects of thermal and thermo-chemical aging on the material properties of emerging ceramic hot gas filters. A honeycomb cordierite monolith with a thin ceramic coating and a rigid candle filter were evaluated.

  8. 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.

  9. Filtered cathodic arc source

    Science.gov (United States)

    Falabella, Steven; Sanders, David M.

    1994-01-01

    A continuous, cathodic arc ion source coupled to a macro-particle filter capable of separation or elimination of macro-particles from the ion flux produced by cathodic arc discharge. The ion source employs an axial magnetic field on a cathode (target) having tapered sides to confine the arc, thereby providing high target material utilization. A bent magnetic field is used to guide the metal ions from the target to the part to be coated. The macro-particle filter consists of two straight solenoids, end to end, but placed at 45.degree. to one another, which prevents line-of-sight from the arc spot on the target to the parts to be coated, yet provides a path for ions and electrons to flow, and includes a series of baffles for trapping the macro-particles.

  10. Event Filter Dataflow Software

    CERN Document Server

    Meessen, C; Bosman, M; Karr, K M; Pacheco, A; Qian, Z; Touchard, F

    2000-01-01

    This document describes the software handling the flow of events through the Event Filter. This is the fourth iteration of the implementation of the code. When compared to previous versions, enhancements come from the feedback by users and can be seen as simplifications while the interfaces have been kept identical. The high level design of the dataflow is briefly reminded. Then, the details of the implementation of the components are given.

  11. Web Content Filtering

    OpenAIRE

    Gómez Hidalgo, José María; Puertas Sanz, Enrique; Carrero García, Francisco Manuel; Buenaga Rodríguez, Manuel de

    2009-01-01

    Across the years, Internet has evolved from an academic network to a truly communication medium, reaching impressive levels of audience and becoming a billionaire business. Many of our working, studying, and entertainment activities are nowadays overwhelmingly limited if we get disconnected from the net of networks. And of course, with the use comes abuse. The World Wide Web features a wide variety of content that are harmful for children or just inappropriate in the workplace. Web filtering ...

  12. Archimedes Mass Filter Vaporizer

    Science.gov (United States)

    Putvinski, S.; Agnew, A. F.; Cluggish, B. P.; Ohkawa, T.; Sevier, L.; Umstadter, K. R.; Dresvin, S. V.; Kuteev, B. V.; Feygenson, O. N.; Ivanov, D. V.; Zverev, S. G.; Miroshnikov, I. V.; Egorov, S. M.; Kiesewetter, D. V.; Maliugin, V. I.

    2001-10-01

    Archimedes Technology Group, Inc., is developing a plasma mass separator called the Archimedes Filter that separates waste oxide mixtures ion by ion into two mass groups: light and heavy. Since high-level waste at Hanford has 99.9its radioactivity associated with heavy elements, the Archimedes Filter can effectively decontaminate over three-quarters of that waste. The Filter process involves some preprocessing followed by volatilization and separation by the magnetic and electric fields of the main plasma. This presentation describes the approach to volatilization of the waste oxy-hydroxide mixture by means of a very high heat flux (q > 10 MW/m2). Such a high heat flux is required to ensure congruent evaporation of the complex oxy-hydroxide mixture and is achieved by injection of small droplets of molten waste into an inductively coupled plasma (ICP) torch. This presentation further addresses different issues related to evaporation of the waste including modeling of droplet evaporation, estimates of parameters of plasma torch, and 2D modeling of the plasma. The experimental test bed for oxide vaporization and results of the initial experiments on oxide evaporation in 60 kW ICP torch will also be described.

  13. Removing Pathogens Using Nano-Ceramic-Fiber Filters

    Science.gov (United States)

    Tepper, Frederick; Kaledin, Leonid

    2005-01-01

    particle size is only 2 nanometers, about the size of a DNA molecule, yet the NanoCeram syringe filter is capable of retaining the dyes as the fluid is passed through the syringe, without much back-pressure. Endotoxins, which are contaminants that are part of the residue of destroyed bacteria, can cause toxic shock and are therefore of major concern in pharmaceutical products. The NanoCeram syringe filter is capable of removing greater than 99.96 percent of the endotoxins.

  14. Improved virus removal in ceramic depth filters modified with MgO.

    Science.gov (United States)

    Michen, Benjamin; Fritsch, Johannes; Aneziris, Christos; Graule, Thomas

    2013-02-05

    Ceramic filters, working on the depth filtration principle, are known to improve drinking water quality by removing human pathogenic microorganisms from contaminated water. However, these microfilters show no sufficient barrier for viruses having diameters down to 20 nm. Recently, it was shown that the addition of positively charged materials, for example, iron oxyhydroxide, can improve virus removal by adsorption mechanisms. In this work, we modified a common ceramic filter based on diatomaceous earth by introducing a novel virus adsorbent material, magnesium oxyhydroxide, into the filter matrix. Such filters showed an improved removal of about 4-log in regard to bacteriophages MS2 and PhiX174. This is explained with the electrostatic enhanced adsorption approach that is the favorable adsorption of negatively charged viruses onto positively charged patches in an otherwise negatively charged filter matrix. Furthermore, we provide theoretical evidence applying calculations according to Derjaguin-Landau-Verwey-Overbeek theory to strengthen our experimental results. However, modified filters showed a significant variance in virus removal efficiency over the course of long-term filtration experiments with virus removal increasing with filter operation time (or filter aging). This is explained by transformational changes of MgO in the filter upon contact with water. It also demonstrates that filter history is of great concern when filters working on the adsorption principles are evaluated in regard to their retention performance as their surface characteristics may alter with use.

  15. 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 adequat...... predict how optimum filter mesh size increases with cell size in microbial filter feeders, a prediction that accords very well with observations. We expect our results to be of significance for small-scale biophysics and trait-based ecological modeling....

  16. Efficiency of Silver Impregnated Porous Pot (SIPP Filters for Production of Clean Potable Water

    Directory of Open Access Journals (Sweden)

    Bhekie Mamba

    2012-08-01

    Full Text Available The Silver Impregnated Porous Pot (SIPP filter is a product of the Tshwane University of Technology manufactured for the production of safe drinking water at a household (home level. Two SIPP devices were assessed for the reduction efficiency of chemical contaminants such as calcium, magnesium, iron, arsenic, fluorides and total organic carbon (TOC as well as microbial contaminants from environmental samples. Turbidity change after filtration, together with correlation between chlorophyll a in the feed water and SIPP’s flow rates were also evaluated in order to give comprehensive guidelines on the quality of intake water that could be filtered through the filter without causing a significant decrease in flow rate. The SIPP filters removed contaminants from environmental water samples as follows: 70% to 92% iron, 36% to 68% calcium, 42% to 82% arsenic, 39% to 98% magnesium, 39% to 95% fluorides, 12% to 35% TOC and 45% to 82% turbidity. The SIPP filters had initial flow rates of 1 L/h to 4 L/h but the flow rates dropped to 0.5 L/h with an increase in cumulative volume of intake water as the filter was used. Turbidity and chemical contaminant reduction rates decreased with accumulating volume of intake water but the filter removed Ca, Fe and Mg to levels that comply with the South African National Standards (SANS 241 and the World Health Organization (WHO guideline values. However, the SIPP filters cannot produce enough water to satisfy the daily drinking water requirement of a typical household (25 L/p·d. Chlorophyll a was associated with a decrease in the flow rate through the SIPP filters.

  17. Tubular biotricking filter for reduction of odour and ammonia from live stock facilities

    DEFF Research Database (Denmark)

    Nielsen, Lars Peter; Andersen, Mathias

    2007-01-01

    between 80 and 100 %. Hardly water soluble components like methanethiol, dimethyl sulfide and methane was reduced by 7-9 %. In relation to the greenhouse effect the degradation of methane fully compensate the nitrous oxide emission from the filters. These results were achieved with a pressure drop......The removal capacity of biological air filters is often limited by the mass transfer from the gas to the liquid phase. In order to optimize this mass transfer we have developed a new biofilter concept based on parallel tubes. The filter is furthermore characterised by the use of counter......-current flow, fresh water supply without recirculation, high air velocity and a special filter material that distributes the water underneath the biofilm with the help of capillary action. In this way the filter is able to reduce contaminants that are hardly soluble in water. The filter has been tested...

  18. Pooled human liver preparations, HepaRG, or HepG2 cell lines for metabolism studies of new psychoactive substances? A study using MDMA, MDBD, butylone, MDPPP, MDPV, MDPB, 5-MAPB, and 5-API as examples.

    Science.gov (United States)

    Richter, Lilian H J; Flockerzi, Veit; Maurer, Hans H; Meyer, Markus R

    2017-09-05

    Metabolism studies play an important role in clinical and forensic toxicology. Because of potential species differences in metabolism, human samples are best suitable for elucidating metabolism. However, in the case of new psychoactive substances (NPS), human samples of controlled studies are not available. Primary human hepatocytes have been described as gold standard for in vitro metabolism studies, but there are some disadvantages such as high costs, limited availability, and variability of metabolic enzymes. Therefore, the aim of our study was to investigate and compare the metabolism of six methylenedioxy derivatives (MDMA, MDBD, butylone, MDPPP, MDPV, MDPB) and two bioisosteric analogues (5-MAPB, 5-API) using pooled human liver microsomes (pHLM) combined with cytosol (pHLC) or pooled human liver S9 fraction (pS9) all after addition of co-substrates for six phase I and II reactions. In addition, HepaRG and HepG2 cell lines were used. Results of the different in vitro tools were compared to each other, to corresponding published data, and to metabolites identified in human urine after consumption of MDMA, MDPV, or 5-MAPB. Incubations with pHLM plus pHLC showed similar results as pS9. A more cost efficient model for prediction of targets for toxicological screening procedures in human urine should be identified. As expected, the incubations with HepaRG provided better results than those with HepG2 concerning number and signal abundance of the metabolites. Due to easy handling without special equipment, incubations with pooled liver preparations should be the most suitable alternative to find targets for toxicological screening procedures for methylenedioxy derivatives and bioisosteric analogues. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Contaminated Sites in Iowa

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — Sites contaminated by hazardous materials or wastes. These sites are those administered by the Contaminated Sites Section of Iowa DNR. Many are sites which are...

  20. Center for Contaminated Sediments

    Data.gov (United States)

    Federal Laboratory Consortium — The U.S. Army Corps of Engineers Center for Contaminated Sediments serves as a clearinghouse for technology and expertise concerned with contaminated sediments. The...

  1. Off Japanese coast: a contaminated ocean; Au Japon, l'ocean contamine comme jamais

    Energy Technology Data Exchange (ETDEWEB)

    Dumas, C.; Linton, M.

    2011-07-15

    According to the IAEA the contamination of the ocean, off the coast of Fukushima is stabilized but radioactivity levels stay high. AREVA is in charge of decontaminating the water used to cool the damaged reactors. The decontamination process is made of 4 steps: (1) the de-oiling of water, (2) precipitation, flocculation and decanting, (3) filtering, and (4) storage of the radioactive sludge. (A.C.)

  2. Approximately liner phase IIR digital filter banks

    OpenAIRE

    J. D. Ćertić; M. D. Lutovac; L. D. Milić

    2013-01-01

    In this paper, uniform and nonuniform digital filter banks based on approximately linear phase IIR filters and frequency response masking technique (FRM) are presented. Both filter banks are realized as a connection of an interpolated half-band approximately linear phase IIR filter as a first stage of the FRM design and an appropriate number of masking filters. The masking filters are half-band IIR filters with an approximately linear phase. The resulting IIR filter banks are compared with li...

  3. Data Filtering and Control Design for Mobile Robots

    OpenAIRE

    Karasalo, Maja

    2009-01-01

    In this thesis, we consider problems connected to navigation and tracking for autonomousrobots under the assumption of constraints on sensors and kinematics. We study formation controlas well as techniques for filtering and smoothing of noise contaminated input. The scientific contributions of the thesis comprise five papers.In Paper A, we propose three cascaded, stabilizing formation controls for multi-agent systems.We consider platforms with non-holonomic kinematic constraints and direction...

  4. Power production from radioactively contaminated biomass and forest litter in Belarus - Phase 1b

    DEFF Research Database (Denmark)

    Roed, Jørn; Andersson, Kasper Grann; Fogh, C.L.

    2000-01-01

    The Chernobyl accident has led to radioactive contamination of vast Belarussian forest areas. A total scheme for remediation of contaminated forest areas and utilisation of the removed biomass in safe energy production is being investigated in aBelarussian-American-Danish collaborative project. H...... from the stream by using a combination of a cyclone and a baghouse filter....

  5. Detecting long-duration cloud contamination in hyper-temporal NDVI imagery

    NARCIS (Netherlands)

    Ali, A.; de Bie, C.A.J.M.; Skidmore, A.K.

    2013-01-01

    Cloud contamination impacts on the quality of hyper-temporal NDVI imagery and its subsequent interpretation. Short-duration cloud impacts are easily removed by using quality flags and an upper envelope filter, but long-duration cloud contamination of NDVI imagery remains. In this paper, an approach

  6. 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...

  7. 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.

  8. 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.

  9. Robust Kriged Kalman Filtering

    Energy Technology Data Exchange (ETDEWEB)

    Baingana, Brian; Dall' Anese, Emiliano; Mateos, Gonzalo; Giannakis, Georgios B.

    2015-11-11

    Although the kriged Kalman filter (KKF) has well-documented merits for prediction of spatial-temporal processes, its performance degrades in the presence of outliers due to anomalous events, or measurement equipment failures. This paper proposes a robust KKF model that explicitly accounts for presence of measurement outliers. Exploiting outlier sparsity, a novel l1-regularized estimator that jointly predicts the spatial-temporal process at unmonitored locations, while identifying measurement outliers is put forth. Numerical tests are conducted on a synthetic Internet protocol (IP) network, and real transformer load data. Test results corroborate the effectiveness of the novel estimator in joint spatial prediction and outlier identification.

  10. 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.

  11. [Prognostic model of the space station contamination stage].

    Science.gov (United States)

    Zlotovol'skiĭ, V M; Smolenskaia, G S

    1998-01-01

    Forty two non-metallic materials, 8 human metabolites and a process liquid (ethylene glycol) were selected for development of a prognostic model of space station contamination by harmful trace admixtures (HTAs). Removal technologies made allowance for absorption by atmospheric condensate (AC) and filter adsorption. Calculations took in 18 HTAs representative of 8 classes of compounds. Simulation modeling allowed to determine HTA migration rates and percent ratio (1), calculate concentrations of contaminants in the atmosphere and atmospheric condensate (2), and to assess filter efficiency by comparison of loads on the filter and a refrigeration/drying set (3). Comparison of empirical and measured data permitted conclusions about adequacy of the model and its potentiality for predicting ramifications of nominal and contingency situations.

  12. 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....

  13. The flexural stiffness and tension state of basalt filter

    Science.gov (United States)

    Khalmuradovich, Sattarov Laziz; Ahmedovich, Kurbanov Abdirahim

    2017-03-01

    In recent years, there is a growing demand in Uzbekistan for new, cheap and competitive products from local raw materials, the demand being directly connected with the expansion and development opportunities of the mining, metallurgical and processing industries. In such conditions, the need for providing a solution of the problems faced by these industries is a very urgent one and requires further comprehensive studies. One of these tasks includes assessment of the force parameters and bending stiffness of basalt fibre filters, aimed at further improving the efficiency of local basalt raw materials and aiding in the manufacture of new, long-lasting, reliable and high-quality products. In this case, we studied the interaction of basalt fibre filter with a gas or liquid medium, the deformed state of the fibres under the action force of the gas or liquid, and the filter recovery process after removal of the load, all of which occur during mechanical filtration. These tasks are of interest because during the mechanical filtration of a gas or liquid (hereinafter, mechanical filtration) from solids, all attention is paid to the quality of the filtering process. The filtering quality, as known, is determined by the degree of contamination in the liquid undergoing treatment, duration of separation of the pulp into solid and liquid phases during the decantation process of the mixture and the amount of gas/ liquid released into the atmosphere along with carbon monoxide and toxic impurities. At the same time, the state and behaviour of the filtering material remain as minor factors, the consideration of which can play a decisive role in the establishment of filter life and work capacity. Solutions to these problems are very urgent and allow one to create new technologies for the production of basalt filters based on force parameters and bending stiffness, wherein the purification occurs without the intervention of chemicals.

  14. A new procedure for treatment of oily slurry using geotextile filters.

    Science.gov (United States)

    Mendonça, M B; Cammarota, M C; Freire, D D C; Ehrlich, M

    2004-07-05

    A new procedure to mitigate the environmental impacts and reduce the cost of disposal of oil slurry is present in this paper. Waste from the petroleum industry has a high environmental impact. Systems for oil-water separation have been used to mitigate the contamination potential of these types of effluents. At the outlet of these systems, the oil is skimmed-off the surface, while the slurry is removed from the base. Due to the high concentration of contaminants, the disposal of this slurry is an environmentally hazardous practice. Usually this type of waste is disposed of in tanks or landfills after removal from the industrial plant. Basically, the proposed procedure utilizes drying beds with geotextile filters to both reduce the water content in the slurry and obtain a less contaminated effluent. Laboratory tests were carried out to simulate the drying system. Four types of filters were analyzed: two non-woven geotextiles, one woven geotextile, and a sand filter.

  15. Bacterial treatment effectiveness of point-of-use ceramic water filters.

    Science.gov (United States)

    Bielefeldt, Angela R; Kowalski, Kate; Summers, R Scott

    2009-08-01

    Laboratory experiments were conducted on six point-of-use (POU) ceramic water filters that were manufactured in Nicaragua; two filters were used by families for ca. 4 years and the other filters had limited prior use in our lab. Water spiked with ca. 10(6)CFU/mL of Escherichia coli was dosed to the filters. Initial disinfection efficiencies ranged from 3 - 4.5 log, but the treatment efficiency decreased with subsequent batches of spiked water. Silver concentrations in the effluent water ranged from 0.04 - 1.75 ppb. Subsequent experiments that utilized feed water without a bacterial spike yielded 10(3)-10(5)CFU/mL bacteria in the effluent. Immediately after recoating four of the filters with a colloidal silver solution, the effluent silver concentrations increased to 36 - 45 ppb and bacterial disinfection efficiencies were 3.8-4.5 log. The treatment effectiveness decreased to 0.2 - 2.5 log after loading multiple batches of highly contaminated water. In subsequent loading of clean water, the effluent water contained filters. This indicates that the silver had some benefit to reducing bacterial contamination by the filter. In general these POU filters were found to be effective, but showed loss of effectiveness with time and indicated a release of microbes into subsequent volumes of water passed through the system.

  16. 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.

  17. 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.

  18. Nanoparticle optical notch filters

    Science.gov (United States)

    Kasinadhuni, Pradeep Kumar

    Developing novel light blocking products involves the design of a nanoparticle optical notch filter, working on the principle of localized surface plasmon resonance (LSPR). These light blocking products can be used in many applications. One such application is to naturally reduce migraine headaches and light sensitivity. Melanopsin ganglion cells present in the retina of the human eye, connect to the suprachiasmatic nucleus (SCN-the body's clock) in the brain, where they participate in the entrainment of the circadian rhythms. As the Melanopsin ganglion cells are involved in triggering the migraine headaches in photophobic patients, it is necessary to block the part of visible spectrum that activates these cells. It is observed from the action potential spectrum of the ganglion cells that they absorb light ranging from 450-500nm (blue-green part) of the visible spectrum with a λmax (peak sensitivity) of around 480nm (blue line). Currently prescribed for migraine patients is the FL-41 coating, which blocks a broad range of wavelengths, including wavelengths associated with melanopsin absorption. The nanoparticle optical notch filter is designed to block light only at 480nm, hence offering an effective prescription for the treatment of migraine headaches.

  19. Contamination of the environment by special purpose centrifuges used in clinical laboratories

    Energy Technology Data Exchange (ETDEWEB)

    Harper, G.J.

    1981-10-01

    The generation of aerosols and the contamination of surfaces arising from the use of a number of special purpose centrifuges have been measured. Except when sealed containers were used all the equipment tested generated airborne particles and contaminated surrounding surfaces. The magnitude of this contamination was shown to be associated with several factors, and it could be considerably reduced by the use of sealed containers, and by fitting air filters. The significance of these findings and their application are discussed.

  20. Robust fault detection filter design

    Science.gov (United States)

    Douglas, Randal Kirk

    The detection filter is a specially tuned linear observer that forms the residual generation part of an analytical redundancy system designed for model-based fault detection and identification. The detection filter has an invariant state subspace structure that produces a residual with known and fixed directional characteristics in response to a known design fault direction. In addition to a parameterization of the detection filter gain, three methods are given for improving performance in the presence of system disturbances, sensor noise, model mismatch and sensitivity to small parameter variations. First, it is shown that by solving a modified algebraic Riccati equation, a stabilizing detection filter gain is found that bounds the H-infinity norm of the transfer matrix from system disturbances and sensor noise to the detection filter residual. Second, a specially chosen expanded-order detection filter is formed with fault detection properties identical to a set of independent reduced-order filters that have no structural constraints. This result is important to the practitioner because the difficult problem of finding a detection filter insensitive to disturbances and sensor noise is converted to the easier problem of finding a set of uncoupled noise insensitive filters. Furthermore, the statistical properties of the reduced-order filter residuals are easier to find than the statistical properties of the structurally constrained detection filter residual. Third, an interpretation of the detection filter as a special case of the dual of the restricted decoupling problem leads to a new detection filter eigenstructure assignment algorithm. The new algorithm places detection filter left eigenvectors, which annihilate the detection spaces, rather than right eigenvectors, which span the detection spaces. This allows for a more flexible observer based fault detection system structure that could not be formulated as a detection filter. Furthermore, the link to the dual

  1. Performance Testing of a Russian Mir Space Station Trace Contaminant Control Assembly

    Science.gov (United States)

    Curtis, R. E.; Perry, J. L.; Abramov, L. H.

    1997-01-01

    A filter assembly which is incorporated into the Russian Trace Contaminant Control Assembly was tested for removal of airborne trace chemical contaminants in a closed loop 9 m(exp 3) system. Given contaminant loading rates and maximum allowable atmospheric concentrations, the Russian system was able to maintain system air concentrations below maximum allowable limits. This was achieved for both a new filter system and for a system where a part of it was pre-loaded to emulate 3 years of system age.

  2. 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.

  3. Reconfigurable Mixed Mode Universal Filter

    Directory of Open Access Journals (Sweden)

    Neelofer Afzal

    2014-01-01

    Full Text Available This paper presents a novel mixed mode universal filter configuration capable of working in voltage and transimpedance mode. The proposed single filter configuration can be reconfigured digitally to realize all the five second order filter functions (types at single output port. Other salient features of proposed configuration include independently programmable filter parameters, full cascadability, and low sensitivity figure. However, all these features are provided at the cost of quite large number of active elements. It needs three digitally programmable current feedback amplifiers and three digitally programmable current conveyors. Use of six active elements is justified by introducing three additional reduced hardware mixed mode universal filter configurations and its comparison with reported filters.

  4. Wavelength Filters in Fibre Optics

    CERN Document Server

    Venghaus, Herbert

    2006-01-01

    Wavelength filters constitute an essential element of fibre-optic networks. This book gives a comprehensive account of the principles and applications of such filters, including their technological realisation. After an introductory chapter on wavelength division multiplexing in current and future fibre optic networks follows a detailed treatment of the phase characteristics of wavelength filters, a factor frequently neglected but of significant importance at high bit rates. Subsequent chapters cover three-dimensional reflection of gratings, arrayed waveguide gratings, fibre Bragg gratings, Fabry-Perot filters, dielectric multilayer filters, ring filters, and interleavers. The book explains the relevant performance parameters, the particular advantages and shortcomings of the various concepts and components, and the preferred applications. It also includes in-depth information on the characteristics of both commercially available devices and those still at the R&D stage. All chapters are authored by inter...

  5. Semi-Hausdorff Fuzzy Filters

    Directory of Open Access Journals (Sweden)

    V. Lakshmana Gomathi Nayagam

    2007-01-01

    Full Text Available The notion of fuzzy filters was studied by Vicente and Aranguren (1988, Lowen (1979, and Ramakrishnan and Nayagam (2002. The notion of fuzzily compactness was introduced and studied by Ramakrishnan and Nayagam (2002. In this paper, an equivalent condition of fuzzily compactness is studied and a new notion of semi-Hausdorffness on fuzzy filters, which cannot be defined in crisp theory of filters, is introduced and studied.

  6. Cuckoo Filter: Simplification and Analysis

    OpenAIRE

    Eppstein, David

    2016-01-01

    The cuckoo filter data structure of Fan, Andersen, Kaminsky, and Mitzenmacher (CoNEXT 2014) performs the same approximate set operations as a Bloom filter in less memory, with better locality of reference, and adds the ability to delete elements as well as to insert them. However, until now it has lacked theoretical guarantees on its performance. We describe a simplified version of the cuckoo filter using fewer hash function calls per query. With this simplification, we provide the first theo...

  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. Effects of electrocardiography contamination and comparison of ECG removal methods on upper trapezius electromyography recordings.

    Science.gov (United States)

    Marker, Ryan J; Maluf, Katrina S

    2014-12-01

    Electromyography (EMG) recordings from the trapezius are often contaminated by the electrocardiography (ECG) signal, making it difficult to distinguish low-level muscle activity from muscular rest. This study investigates the influence of ECG contamination on EMG amplitude and frequency estimations in the upper trapezius during muscular rest and low-level contractions. A new method of ECG contamination removal, filtered template subtraction (FTS), is described and compared to 30 Hz high-pass filter (HPF) and averaged template subtraction (ATS) methods. FTS creates a unique template of each ECG artifact using a low-pass filtered copy of the contaminated signal, which is subtracted from contaminated periods in the original signal. ECG contamination results in an over-estimation of EMG amplitude during rest in the upper trapezius, with negligible effects on amplitude and frequency estimations during low-intensity isometric contractions. FTS and HPF successfully removed ECG contamination from periods of muscular rest, yet introduced errors during muscle contraction. Conversely, ATS failed to fully remove ECG contamination during muscular rest, yet did not introduce errors during muscle contraction. The relative advantages and disadvantages of different ECG contamination removal methods should be considered in the context of the specific motor tasks that require analysis.

  10. Filters and supports in orthoalgebras

    Science.gov (United States)

    Foulis, D. J.; Greechie, R. J.; Rüttimann, G. T.

    1992-05-01

    An orthoalgebra, which is a natural generalization of an orthomodular lattice or poset, may be viewed as a “logic” or “proposition system” and, under a welldefined set of circumstances, its elements may be classified according to the Aristotelian modalities: necessary, impossible, possible, and contingent. The necessary propositions band together to form a local filter, that is, a set that intersects every Boolean subalgebra in a filter. In this paper, we give a coherent account of the basic theory of Orthoalgebras, define and study filters, local filters, and associated structures, and prove a version of the compactness theorem in classical algebraic logic.

  11. Spatial filtering with photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Maigyte, Lina [Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, Rambla Sant Nebridi 22, Terrassa 08222 (Spain); Staliunas, Kestutis [Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, Rambla Sant Nebridi 22, Terrassa 08222 (Spain); Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, Barcelona 08010 (Spain)

    2015-03-15

    Photonic crystals are well known for their celebrated photonic band-gaps—the forbidden frequency ranges, for which the light waves cannot propagate through the structure. The frequency (or chromatic) band-gaps of photonic crystals can be utilized for frequency filtering. In analogy to the chromatic band-gaps and the frequency filtering, the angular band-gaps and the angular (spatial) filtering are also possible in photonic crystals. In this article, we review the recent advances of the spatial filtering using the photonic crystals in different propagation regimes and for different geometries. We review the most evident configuration of filtering in Bragg regime (with the back-reflection—i.e., in the configuration with band-gaps) as well as in Laue regime (with forward deflection—i.e., in the configuration without band-gaps). We explore the spatial filtering in crystals with different symmetries, including axisymmetric crystals; we discuss the role of chirping, i.e., the dependence of the longitudinal period along the structure. We also review the experimental techniques to fabricate the photonic crystals and numerical techniques to explore the spatial filtering. Finally, we discuss several implementations of such filters for intracavity spatial filtering.

  12. Optimization of integrated polarization filters

    CERN Document Server

    Gagnon, Denis; Déziel, Jean-Luc; Dubé, Louis J

    2014-01-01

    This study reports on the design of small footprint, integrated polarization filters based on engineered photonic lattices. Using a rods-in-air lattice as a basis for a TE filter and a holes-in-slab lattice for the analogous TM filter, we are able to maximize the degree of polarization of the output beams up to 98 % with a transmission efficiency greater than 75 %. The proposed designs allow not only for logical polarization filtering, but can also be tailored to output an arbitrary transverse beam profile. The lattice configurations are found using a recently proposed parallel tabu search algorithm for combinatorial optimization problems in integrated photonics.

  13. 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

  14. Filter selection using genetic algorithms

    Science.gov (United States)

    Patel, Devesh

    1996-03-01

    Convolution operators act as matched filters for certain types of variations found in images and have been extensively used in the analysis of images. However, filtering through a bank of N filters generates N filtered images, consequently increasing the amount of data considerably. Moreover, not all these filters have the same discriminatory capabilities for the individual images, thus making the task of any classifier difficult. In this paper, we use genetic algorithms to select a subset of relevant filters. Genetic algorithms represent a class of adaptive search techniques where the processes are similar to natural selection of biological evolution. The steady state model (GENITOR) has been used in this paper. The reduction of filters improves the performance of the classifier (which in this paper is the multi-layer perceptron neural network) and furthermore reduces the computational requirement. In this study we use the Laws filters which were proposed for the analysis of texture images. Our aim is to recognize the different textures on the images using the reduced filter set.

  15. Kalman filtering implementation with Matlab

    OpenAIRE

    Kleinbauer, Rachel

    2004-01-01

    1960 und 1961 veröffentlichte Rudolf Emil Kalmen seine Arbeiten über einen rekursiven prädiktiven Filter, der auf dem Gebrauch von rekursiven Algorithmen basiert. Damit revolutionierte er das Feld der Schätzverfahren. Seitdem ist der sogenannte Kalman Filter Gegenstand ausführlicher Forschung und findet bis heute Anwendung in zahlreichen Gebieten. Der Kalman Filter schätzt den Zustand eines dynamischen Systems, auch wenn die exakte Form dieses Systems unbekannt ist. Der Filter ist sehr lei...

  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. Design and fabrication of magnetic coolant filter

    Science.gov (United States)

    Prashanth, B. N.

    2017-07-01

    Now a day's use of coolants in industry has become dominant because of high production demands. Coolants not only help in speeding up the production but also provide many advantages in the metal working operation. As the consumption of coolants is very high a system is badly in need, so as to recirculate the used coolant. Also the amount of hazardous waste generated by industrial plants has become an increasingly costly problem for the manufactures and an additional stress on the environment. Since the purchase and disposal of the spent cutting fluids is becoming increasingly expensive, fluid recycling is a viable option for minimizing the cost. Separation of metallic chips from the coolants by using magnetic coolant separation has proven a good management and maintenance of the cutting fluid. By removing the metallic chips, the coolant life is greatly extended, increases the machining quality and reduces downtime. Above being the case, a magnetic coolant filter is developed which utilizes high energy permanent magnets to develop a dense magnetic field along a narrow flow path into which the contaminated coolant is directed. The ferromagnetic particles captured and aligned by the dense magnetic field, from the efficient filter medium. This enables the unit to remove ferromagnetic particles from the coolant. Magnetic coolant filters use the principle of magnetic separation to purify the used coolant. The developed magnetic coolant separation has the capability of purifying 40 litres per minute of coolant with the size of the contaminants ranging from 1 µm to 30 µm. The filter will be helpful in saving the production cost as the cost associated with the proposed design is well justified by the cost savings in production. The magnetic field produced by permanent magnets will be throughout the area underneath the reservoir. This produces magnetic field 30mm above the coolant reservoir. Very fine particles are arrested without slip. The magnetic material used will not

  18. Resuspended contaminated sediments cause sublethal stress to oysters: A biomarker differentiates total suspended solids and contaminant effects.

    Science.gov (United States)

    Edge, Katelyn J; Dafforn, Katherine A; Simpson, Stuart L; Ringwood, Amy H; Johnston, Emma L

    2015-06-01

    Resuspended contaminated sediments represent an important route of contaminant exposure for aquatic organisms. During resuspension events, filter-feeding organisms are exposed to contaminants, in both the dissolved form (at the gills) and the particulate form (in the digestive system). In addition, these organisms must manage the physical stress associated with an increase in total suspended solids (TSS). To date, few studies have experimentally compared the contributions to biological stress of contaminated and clean suspended solids. The authors mixed field-collected sediments (<63 μm) from clean and contaminated field sites to create 4 treatments of increasing metal concentrations. Sydney rock oysters were then exposed to sediment treatments at different TSS concentrations for 4 d, and cellular biomarkers (lysosomal membrane stability, lipid peroxidation, and glutathione) were measured to evaluate sublethal toxicity. Lysosomal membrane stability was the most sensitive biomarker for distinguishing effects from resuspended contaminated sediments, as increasing amounts of contaminated TSS increased lysosomal membrane destabilization. The authors' results illustrate the importance of considering contaminant exposures from resuspended sediments when assessing the toxicity of contaminants to aquatic organisms. © 2015 SETAC.

  19. Specific filters applied in nuclear medicine services

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, Vitor S.; Crispim, Verginia R., E-mail: verginia@con.ufrj.b [Coordenacao dos Programas de Pos-Graduacao de Engenharia (PEN/COPPE/UFRJ), RJ (Brazil). Programa de Engenharia Nuclear; Brandao, Luis E.B. [Instituto de Engenharia Nuclear (IEN/CNEN-RJ) Rio de Janeiro, RJ (Brazil)

    2011-07-01

    In Nuclear Medicine, radioiodine, in various chemical forms, is a key tracer used in diagnostic practices and/or therapy. Due to its high volatility, medical professionals may incorporate radioactive iodine during the preparation of the dose to be administered to the patient. In radioactive iodine therapy doses ranging from 3.7 to 7.4 GBq per patient are employed. Thus, aiming at reducing the risk of occupational contamination, we developed a low cost filter to be installed at the exit of the exhaust system where doses of radioactive iodine are fractionated, using domestic technology. The effectiveness of radioactive iodine retention by silver impregnated silica [10%] crystals and natural activated carbon was verified using radiotracer techniques. The results showed that natural activated carbon is effective for I{sub 2} capture for a large or small amount of substrate but its use is restricted due to its low flash point (150 deg C). Besides, when poisoned by organic solvents, this flash point may become lower, causing explosions if absorbing large amounts of nitrates. To hold the CH{sub 3}I gas, it was necessary to increase the volume of natural activated carbon since it was not absorbed by SiO{sub 2} + Ag crystals. We concluded that, for an exhaust flow range of (306 {+-} 4) m{sup 3}/h, a double stage filter using SiO{sub 2} + Ag in the first stage and natural activated carbon in the second is sufficient to meet radiological safety requirements. (author)

  20. 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.

  1. Avaliação de filtros domésticos comerciais para purificação de águas e retenção de contaminantes inorgânicos Evaluation of domestic commercial filters to waters purification and retention of inorganic contaminates

    OpenAIRE

    Nilva Aparecida Ressinetti Pedro; Berenice Mandel Brígido; Maria Irene Cibela Badolato; José Leopoldo Ferreira Antunes; Elisabeth de Oliveira

    1997-01-01

    Twenty domestic commercial filters, in order to determine the percentual retention of color, turbidity, dry residue, bicarbonates, carbonates, total hardness, nitrogens, iron, chlorides, fluorides, and residual chlorine (parameters of food legislation) and sulphides in thirteen water samples proceeding from springs, wells, rivers, lakes, drinking patterns and standards, before and after purification were evaluated. The results showed that purifiers presented adequate retention for nitrates (7...

  2. Application of DFT Filter Banks and Cosine Modulated Filter Banks in Filtering

    Science.gov (United States)

    Lin, Yuan-Pei; Vaidyanathan, P. P.

    1994-01-01

    None given. This is a proposal for a paper to be presented at APCCAS '94 in Taipei, Taiwan. (From outline): This work is organized as follows: Sec. II is devoted to the construction of the new 2m channel under-decimated DFT filter bank. Implementation and complexity of this DFT filter bank are discussed therein. IN a similar manner, the new 2m channel cosine modulated filter bank is discussed in Sec. III. Design examples are given in Sec. IV.

  3. Application of DFT Filter Banks and Cosine Modulated Filter Banks in Filtering

    Science.gov (United States)

    Lin, Yuan-Pei; Vaidyanathan, P. P.

    1994-01-01

    None given. This is a proposal for a paper to be presented at APCCAS '94 in Taipei, Taiwan. (From outline): This work is organized as follows: Sec. II is devoted to the construction of the new 2m channel under-decimated DFT filter bank. Implementation and complexity of this DFT filter bank are discussed therein. IN a similar manner, the new 2m channel cosine modulated filter bank is discussed in Sec. III. Design examples are given in Sec. IV.

  4. Bridging the ensemble Kalman filter and particle filters: the adaptive Gaussian mixture filter

    OpenAIRE

    Stordal, Andreas Størksen; Karlsen, Hans A.; Nævdal, Geir; Hans J. Skaug; Vallès, Brice

    2010-01-01

    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 (EnKF) 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 a Gauss...

  5. Bioremediation of contaminated groundwater

    Science.gov (United States)

    Hazen, Terry C.; Fliermans, Carl B.

    1995-01-01

    An apparatus and method for in situ remediation of contaminated subsurface soil or groundwater contaminated by chlorinated hydrocarbons. A nutrient fluid is selected to stimulate the growth and reproduction of indigenous subsurface microorganisms that are capable of degrading the contaminants; an oxygenated fluid is selected to create a generally aerobic environment for these microorganisms to degrade the contaminants, leaving only pockets that are anaerobic. The nutrient fluid is injected periodically while the oxygenated fluid is injected continuously and both are extracted so that both are drawn across the plume. The nutrient fluid stimulates microbial colony growth; withholding it periodicially forces the larger, healthy colony of microbes to degrade the contaminants. Treatment is continued until the subsurface concentration of contaminants is reduced to an acceptable, preselected level. The nutrient fluid can be methane and the oxygenated fluid air for stimulating production of methanotrophs to break down chlorohydrocarbons, especially trichloroethylene (TCE) and tetrachloroethylene.

  6. JPL Contamination Control Engineering

    Science.gov (United States)

    Blakkolb, Brian

    2013-01-01

    JPL has extensive expertise fielding contamination sensitive missions-in house and with our NASA/industry/academic partners.t Development and implementation of performance-driven cleanliness requirements for a wide range missions and payloads - UV-Vis-IR: GALEX, Dawn, Juno, WFPC-II, AIRS, TES, et al - Propulsion, thermal control, robotic sample acquisition systems. Contamination control engineering across the mission life cycle: - System and payload requirements derivation, analysis, and contamination control implementation plans - Hardware Design, Risk trades, Requirements V-V - Assembly, Integration & Test planning and implementation - Launch site operations and launch vehicle/payload integration - Flight ops center dot Personnel on staff have expertise with space materials development and flight experiments. JPL has capabilities and expertise to successfully address contamination issues presented by space and habitable environments. JPL has extensive experience fielding and managing contamination sensitive missions. Excellent working relationship with the aerospace contamination control engineering community/.

  7. Digital Filters Using Identical Blocks

    Directory of Open Access Journals (Sweden)

    S. C. Dutta

    1985-07-01

    Full Text Available Improved response of non-recursive digital filters is achieved using Amplitude Change Functions (ACFs on a prototype filter. A generalized ACF with interesting properties is suggested. Methods for achieving variable cut-off frequency and frequency transformation are explained. A modular hardware implementation is also presented.

  8. Digital filter synthesis computer program

    Science.gov (United States)

    Moyer, R. A.; Munoz, R. M.

    1968-01-01

    Digital filter synthesis computer program expresses any continuous function of a complex variable in approximate form as a computational algorithm or difference equation. Once the difference equation has been developed, digital filtering can be performed by the program on any input data list.

  9. Polarizing Filter for Integrated Optics

    Science.gov (United States)

    Ramer, O. G.; Goss, W. C.; Goldstein, R.

    1986-01-01

    Polarizing filter for titanium-doped lithium niobate light waveguide suppresses transverse magnetic (TM) mode of light propagation while allowing transverse electric (TE) mode to continue on its way. Filter - lithium niobate crystal - is expected to find many applications in integrated optical circuits.

  10. Filter-extruded liposomes revisited

    DEFF Research Database (Denmark)

    Hinna, Askell; Steiniger, Frank; Hupfeld, Stefan;

    2016-01-01

    Filter-extrusion is a widely used technique for down-sizing of phospholipid vesicles. In order to gain a detailed insight into size and size distributions of filter-extruded vesicles composed of egg phosphatidyl-choline (with varying fractions of cholesterol) – in relation to extrusionparameters...

  11. Cold Crystal Reflector Filter Concept

    CERN Document Server

    Muhrer, G

    2014-01-01

    In this paper the theoretical concept of a cold crystal reflector filter will be presented. The aim of this concept is to balance the shortcoming of the traditional cold polycrystalline reflector filter, which lies in the significant reduction of the neutron flux right above (in energy space) or right below (wavelength space) the first Bragg edge.

  12. Tracking speckle displacement by double Kalman filtering

    Institute of Scientific and Technical Information of China (English)

    Donghui Li; Li Guo

    2006-01-01

    @@ A tracking technique using two sequentially-connected Kalman filter for tracking laser speckle displacement is presented. One Kalman filter tracks temporal speckle displacement, while another Kalman filter tracks spatial speckle displacement. The temporal Kalman filter provides a prior for the spatial Kalman filter, and the spatial Kalman filter provides measurements for the temporal Kalman filter. The contribution of a prior to estimations of the spatial Kalman filter is analyzed. An optical analysis system was set up to verify the double-Kalman-filter tracker's ability of tracking laser speckle's constant displacement.

  13. Identification Filtering with fuzzy estimations

    Directory of Open Access Journals (Sweden)

    J.J Medel J

    2012-10-01

    Full Text Available A digital identification filter interacts with an output reference model signal known as a black-box output system. The identification technique commonly needs the transition and gain matrixes. Both estimation cases are based on mean square criterion obtaining of the minimum output error as the best estimation filtering. The evolution system represents adaptive properties that the identification mechanism includes considering the fuzzy logic strategies affecting in probability sense the evolution identification filter. The fuzzy estimation filter allows in two forms describing the transition and the gain matrixes applying actions that affect the identification structure. Basically, the adaptive criterion conforming the inference mechanisms set, the Knowledge and Rule bases, selecting the optimal coefficients in distribution form. This paper describes the fuzzy strategies applied to the Kalman filter transition function, and gain matrixes. The simulation results were developed using Matlab©.

  14. 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 ...

  15. Evaluation of an iron-filtered epithermal neutron beam for neutron-capture therapy.

    Science.gov (United States)

    Musolino, S V; McGinley, P H; Greenwood, R C; Kliauga, P; Fairchild, R G

    1991-01-01

    An epithermal neutron filter using iron, aluminum, and sulfur was evaluated to determine if the therapeutic performance could be improved with respect to aluminum-sulfur-based filters. An empirically optimized filter was developed that delivered a 93% pure beam of 24-keV epithermal neutrons. It was expected that a thick filter using iron with a density thickness greater than 200 g/cm2 would eliminate the excess gamma contamination found in Al-S filters. This research showed that prompt gamma production from neutron interactions in iron was the dominant dose component. Dosimetric parameters of the beam were determined from the measurement of absorbed dose in air, thermal neutron flux in a head phantom, neutron and gamma spectroscopy, and microdosimetry.

  16. A Simple Slow-Sand Filter for Drinking Water Purification

    Directory of Open Access Journals (Sweden)

    K. O. Yusuf

    2017-04-01

    Full Text Available Water-borne diseases are commonly encountered when pathogen-contaminated water is consumed. In rural areas, water is usually obtained from ponds, open shallow wells, streams and rain water during rainy season. Rain water is often contaminated by pathogens due to unhygienic of physical and chemical conditions of the roofs thereby making it unsafe for consumption. A simple slow sand filter mechanism was designed and fabricated for purification of water in rural areas where electricity is not available to power water purification devices. Rain water samples were collected from aluminum roof, galvanized roof and thatched roof. The waters samples were allowed to flow through the slow sand filter. The values of turbidity, total dissolved solids, calcium, nitrite, faecal coliform and total coliform from unfiltered water through thatched roof were 0.92 NTU, 27.23 mg/l, 6 mg/l, 0.16 mg/l, 5cfu/100ml and 6.0 cfu/100ml, respectively while the corresponding values for slow sand filter from thatched roof were 0.01 NTU, 0.23 mg/l, 2.5 mg/l, 0.1 mg/l, 0 cfu/100ml and 0 cfu/100ml, respectively. The values of turbidity, total dissolved solid, nitrite, calcium, faecal coliform and total coliform from unfiltered water for aluminum roof were 0.82 NTU, 23.68 mg/l, 2.70 mg/l, 1.0 mg/l, 4 cfu/100ml and 4cfu/100ml, respectively while the corresponding values for slow sand filter were 0.01 NTU, 0.16 mg/l, 0.57 mg/l, 0.2 mg/l, 0 cfu/100ml and 0 cfu/100ml, respectively. The values obtained for galvanized roof were also satisfactory. The slow sand filter is recommended for used in rural areas for water purification to prevent risk of water-borne diseases.

  17. Laboratory Studies on Granular Filters and Their Relationship to Geotextiles for Stormwater Pollutant Reduction

    Directory of Open Access Journals (Sweden)

    Parneet Paul

    2015-04-01

    Full Text Available Applications of geotextiles within tertiary stormwater treatment systems and for stormwater infiltration can provide a substrate for biofilm formation, enabling biological treatment of contaminants. Geotextiles can serve as an efficient part of stormwater filtration within the urban water environment. The project assessed the applications of three experimental granular filters as a sustainable urban drainage system (SUDS for the decomposition of organic pollutant loading present in stormwater. The three filter rigs were packed with alternating layers of filter media consisting of gravel, pea gravel, sand and either a single, double or no layer of geotextile membrane. A nonwoven geotextile was layered within the filter media. The hydraulic loading capacity for the three filters matched that commonly used with conventional sand filters systems. Water quality parameters were quantified by measuring suspended solids, chemical oxygen demand, dissolved oxygen, pH, nitrate-nitrogen, and phosphate concentrations. It was found that Filter Rig No. 3 (upper and lower geotextile membrane and Filter Rig No. 2 (single geotextile membrane had a significant statistical difference in treatment performance from Filter Rig No. 1 (no geotextile membrane.

  18. Organophosphates in aircraft cabin and cockpit air--method development and measurements of contaminants.

    Science.gov (United States)

    Solbu, Kasper; Daae, Hanne Line; Olsen, Raymond; Thorud, Syvert; Ellingsen, Dag Gunnar; Lindgren, Torsten; Bakke, Berit; Lundanes, Elsa; Molander, Paal

    2011-05-01

    Methods for measurements and the potential for occupational exposure to organophosphates (OPs) originating from turbine and hydraulic oils among flying personnel in the aviation industry are described. Different sampling methods were applied, including active within-day methods for OPs and VOCs, newly developed passive long-term sample methods (deposition of OPs to wipe surface areas and to activated charcoal cloths), and measurements of OPs in high-efficiency particulate air (HEPA) recirculation filters (n = 6). In total, 95 and 72 within-day OP and VOC samples, respectively, have been collected during 47 flights in six different models of turbine jet engine, propeller and helicopter aircrafts (n = 40). In general, the OP air levels from the within-day samples were low. The most relevant OP in this regard originating from turbine and engine oils, tricresyl phosphate (TCP), was detected in only 4% of the samples (min-max cockpit air, was an order of magnitude higher as compared to after engine replacement (p = 0.02).

  19. Ethanol extract of Zingiber officinale Rose induces cell apoptosis and inhibits cell proliferation in mice with HepA liver cancer.%生姜醇提物诱导荷瘤鼠HepA细胞凋亡的研究

    Institute of Scientific and Technical Information of China (English)

    刘辉; 袁健; 李勇; 王玉

    2011-01-01

    目的 探讨生姜醇提物对荷瘤鼠HepA细胞生长及凋亡的影响.方法 建立荷瘤(HepA肝癌细胞)鼠动物模型,以生姜醇提物40 g/kg(高剂量)、10 g/kg(低剂量)灌胃给药20 d,测量荷瘤鼠生存时间及肿瘤重量变化,计算各组生命延长率及抑瘤率;采用TUNEL法检测组织凋亡指数(AI),观察生姜醇提物对荷瘤鼠体征及凋亡的影响.结果 生姜醇提物能明显抑制肿瘤的生长,延长半数死亡时间,给药组生命延长率达到30%~60%,高剂量组抑瘤率为32.4%;生姜醇提物可诱导荷瘤细胞凋亡,凋亡指数与对照组比较差异有显著性(P<0.01).结论 生姜醇提物可抑制荷瘤鼠肝癌细胞的生长,促进细胞凋亡.%Objective To evaluate the cell proliferation and apoptosis induced by ethanol extract of Zingiber officinale Rose in mice with HepA liver cancer. Methods The transplanted tumor model was established with subcutaneous injection of HepA cell in mice. Seventy mice were randomly divided into 7 groups. Ethanol extract of Zingiber officinale Rose lavage in 40 mg/kg ( high dose ) or 10 mg/kg ( low dose ) was performed in mice for 20 days. The sival and tumor inhibition rate were measured. Meanwhile, tumor apoptosis index assessed using TUNEL. Results Significant prolongation of sival was observed in all groups of( P <0. 05 ). Tumor inhibition rate was 32.4% in mice with high dose ethanol extract of Zingiber officinale Rose. Furthermore, significant increase of apoptosis index was revealed in test groups ( P < 0. 05 ). Conclusion Ethanol extract of Zingiber officinale Rose induces cell apoptosis and inhibits cell proliferation.

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

    DEFF Research Database (Denmark)

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

    2008-01-01

    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....... 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...

  1. Evaluation of the Impact of Fatty Acid Methyl Ester (FAME) Contamination on the Thermal Stability of Jet A

    Science.gov (United States)

    2013-11-01

    Carbon-Type Amorphous Material with Metalic and Non-Metalic Constituents Analysis of “Brown Goo” HP Pump Filter Elt . Line Intensity (c/s) Error...Pump Filter FINDING Carbon-containing amorphous material with metals and non-metals contamination Elt . Line Intensity (c/s) Error 2-sig Conc Units...6 4.1 Materials

  2. Contaminated soil concrete blocks

    NARCIS (Netherlands)

    Korte, de A.C.J.; Brouwers, H.J.H.; Limbachiya, Mukesh C.; Kew, Hsein Y.

    2009-01-01

    According to Dutch law the contaminated soil needs to be remediated or immobilised. The main focus in this article is the design of concrete blocks, containing contaminated soil, that are suitable for large production, financial feasible and meets all technical and environmental requirements. In ord

  3. 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...

  4. Shunt Active Filter in Damping Harmonics Propagation

    Directory of Open Access Journals (Sweden)

    BERBAOUI, B.

    2010-08-01

    Full Text Available This paper deals with a hybrid shunt active power filter applied on 500 kV HVDC, after a description of the causes and effects harmonic pollution which may damage equipments and interrupt electric power customers service; in this paper we present the deferent solutions of this problem among one has to study the two most recent types of filtering: passive and hybrid filter. The hybrid filter consists of active filter connected in shunt with passive filter. The hybrid shunt active filter proposed is based on three levels PWM inverter and characterized by detecting the harmonic current flowing into the passive filter and controlled by notch algorithm. This structure has been applied on a test HVDC power system, is presented as a technical solution makes it possible to eliminate the disadvantages from passive filtering, and also economic price of active filtering part. The simulation results justified the effectiveness of this type of filter face of the classic passive filter.

  5. Avaliação de filtros domésticos comerciais para purificação de águas e retenção de contaminantes inorgânicos Evaluation of domestic commercial filters to waters purification and retention of inorganic contaminates

    Directory of Open Access Journals (Sweden)

    Nilva Aparecida Ressinetti Pedro

    1997-04-01

    Full Text Available Twenty domestic commercial filters, in order to determine the percentual retention of color, turbidity, dry residue, bicarbonates, carbonates, total hardness, nitrogens, iron, chlorides, fluorides, and residual chlorine (parameters of food legislation and sulphides in thirteen water samples proceeding from springs, wells, rivers, lakes, drinking patterns and standards, before and after purification were evaluated. The results showed that purifiers presented adequate retention for nitrates (74.8 ± 16.2 % and residual chlorine (74.0 ± 11.2 and medium retention for sulphides (61.7 ± 11.3; while porcelain plus activated carbon filters presented adequate retention for color (90.0 ± 19.7, turbidity (76.4 ± 18.4 and iron (83.5 ± 15.1. Therefore the retention of carbonates, bicarbonates, total hardness, chlorides, dry residue, fluorides, ammonium nitrogens and nitrites was less than 10%, and the values of pH didn't show significant variation, for all the filters studied.

  6. Nanophotonic filters for digital imaging

    Science.gov (United States)

    Walls, Kirsty

    There has been an increasing demand for low cost, portable CMOS image sensors because of increased integration, and new applications in the automotive, mobile communication and medical industries, amongst others. Colour reproduction remains imperfect in conventional digital image sensors, due to the limitations of the dye-based filters. Further improvement is required if the full potential of digital imaging is to be realised. In alternative systems, where accurate colour reproduction is a priority, existing equipment is too bulky for anything but specialist use. In this work both these issues are addressed by exploiting nanophotonic techniques to create enhanced trichromatic filters, and multispectral filters, all of which can be fabricated on-chip, i.e. integrated into a conventional digital image sensor, to create compact, low cost, mass produceable imaging systems with accurate colour reproduction. The trichromatic filters are based on plasmonic structures. They exploit the excitation of surface plasmon resonances in arrays of subwavelength holes in metal films to filter light. The currently-known analytical expressions are inadequate for optimising all relevant parameters of a plasmonic structure. In order to obtain arbitrary filter characteristics, an automated design procedure was developed that integrated a genetic algorithm and 3D finite-difference time-domain tool. The optimisation procedure's efficacy is demonstrated by designing a set of plasmonic filters that replicate the CIE (1931) colour matching functions, which themselves mimic the human eye's daytime colour response.

  7. Decreasing the contamination and toxicity of a heavily contaminated soil by in situ bioremediation

    Science.gov (United States)

    Groudev, Stoyan; Georgiev, Plamen; Spasova, Irena; Nikolova, Marina

    2013-04-01

    An experimental plot of 140 m2 consisting of acidic soil heavily contaminated with uranium, non-ferrous metals (mainly Cu, Zn and Cd) and arsenic was treated in situ under real field conditions using the activity of the indigenous soil microflora. This activity was enhanced by suitable changes of some essential environmental factors such as pH and water, oxygen and nutrient contents of the soil. The treatment was connected with solubilization and removal of contaminants from the top soil layers (horizon A) due to the joint action of the soil microorganisms (mainly acidophilic chemolithotrophic bacteria) and leach solutions (diluted sulphuric acid). The dissolved contaminants were transferred to the soil horizon B and were removed from the soil profile through a system of drainage collecting pipes. The contaminated soil effluents were treated by means of a multi-component passive system consisting of an anoxic alkalizing drain, a permeable reactive multibarrier and a rock filter. The contamination and toxicity of the soil were regularly tested during the cleaning procedure and were considerably decreased at the end of the treatment.

  8. Vitrification of transuranic and beta-gamma contaminated solid wastes

    Energy Technology Data Exchange (ETDEWEB)

    Dukes, M.D.

    1980-06-01

    Vitrification of solid transuranic contaminated (TRU) wastes alone and with high-level liquid wastes (HLLW) was studied. Homogeneous glasses containing 20 to 30 wt % ash were made by using glass frits previously developed at the Savannah River Plant and Pacific Northwest Laboratories. If the ash is vitrified along with the HLLW, 1.0 wt % as can be added to the waste forms without affecting their quality. This loading of ash is well above the loading required by the relative amounts of HLLW and TRU ash that will be processed at the Savannah River Plant. Vitrification of TRU-contaminated electropolishing sludges and high efficiency particular air filter materials along with HLLW would require an increase in the quantity of glass to be produced. However, if these TRU-contaminated solids were vitrified with the HLLW, the addition of low-level beta-gamma contaminated ash would require no further increase in glass production.

  9. Simulasi Perancangan Filter Analog dengan Respon Chebyshev

    Directory of Open Access Journals (Sweden)

    RUSTAMAJI RUSTAMAJI

    2016-02-01

    Full Text Available Abstrak Dalam suatu sistem komunikasi penggunaan rangkaian filter sangat penting. Salah satu cara untuk memudahkan dalam perancangan sebuah filter dilakukanlah teknik simulasi. Penelitian ini bertujuan untuk merancang simulasi yang menghasilkan respon filter jenis chebyshev serta menghasilkan nilai komponen induktor (L dan kapasitor (C yang dibutuhkan untuk merangkai filter. Simulasi yang dirancang pada penelitian ini menggunakan Graphical User Interface (GUI. Dari simulasi yang dilakukan, didapatkan respon Chebyshev pada low pass filter, high pass filter, band pass filter, dan band stop filter sudah sesuai dengan input yang dimasukkan ke dalam parameter program dan sesuai dengan teori respon filter Chebyshev. Hasil Simulasi dari rangkaian band pass filter dan band stop filter dengan menggunakan Electronic Workbench (EWB, menunjukkan respon dengan pergeseran frekuensi sebesar 0,1 kHz lebih tinggi dari frekuensi yang diharapkan. Kata Kunci :filter, Chebyshev, band, respon frekuensi.   Abstract On communication system using filter is very important. One way to simplify the design of filter undertaken a simulation technique. This research aims to design a simulation that generates the filter response of chebyshev and generate the value component of the inductor (L and capacitor (C that needed for constructing the filter. This Simulation using Graphical User Interface (GUI. From result simulation, response in low pass filter, high pass filter, band pass filter, band stop filter and is in compliance with the input entered into the program and in accordance with the theory of Chebyshev filter response. The simulation of the band pass filter and bands stop filter by using electronic workbench ( EWB , show a response with shifts frequency of 0.1 khz higher than frequency expected.   Keywords: filter, Chebyshev, band, frequency respons

  10. 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

  11. Tunable Imaging Filters in Astronomy

    CERN Document Server

    Bland-Hawthorn, J

    2000-01-01

    While tunable filters are a recent development in night time astronomy, they have long been used in other physical sciences, e.g. solar physics, remote sensing and underwater communications. With their ability to tune precisely to a given wavelength using a bandpass optimized for the experiment, tunable filters are already producing some of the deepest narrowband images to date of astrophysical sources. Furthermore, some classes of tunable filters can be used in fast telescope beams and therefore allow for narrowband imaging over angular fields of more than a degree over the sky.

  12. 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

  13. 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.

  14. Nonlinear Filtering and Approximation Techniques

    Science.gov (United States)

    1988-10-01

    e par des iquations de dimension finie, les 6quations du filtre de Kalman : X +h~pklk Xk=(1 + bAt).kk..I + e2+h2 pl_(k - h( + b~t)Xk-... (6 -kIj (1...Equation. 3. Piecewise Linear Filtering with Small Observation Noise. 4. Filtres Approches pour un Probleme de Fitrage Nonlineaire Discretise avec Petit...finite dimensional solution, namely the Kalman filter (which is the extended Kalman filter for (0.1) ). The above considerations tend to indicate that

  15. 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

  16. Why conventional detection methods fail in identifying the existence of contamination events.

    Science.gov (United States)

    Liu, Shuming; Li, Ruonan; Smith, Kate; Che, Han

    2016-04-15

    Early warning systems are widely used to safeguard water security, but their effectiveness has raised many questions. To understand why conventional detection methods fail to identify contamination events, this study evaluates the performance of three contamination detection methods using data from a real contamination accident and two artificial datasets constructed using a widely applied contamination data construction approach. Results show that the Pearson correlation Euclidean distance (PE) based detection method performs better for real contamination incidents, while the Euclidean distance method (MED) and linear prediction filter (LPF) method are more suitable for detecting sudden spike-like variation. This analysis revealed why the conventional MED and LPF methods failed to identify existence of contamination events. The analysis also revealed that the widely used contamination data construction approach is misleading.

  17. Concrete ensemble Kalman filters with rigorous catastrophic filter divergence.

    Science.gov (United States)

    Kelly, David; Majda, Andrew J; Tong, Xin T

    2015-08-25

    The ensemble Kalman filter and ensemble square root filters are data assimilation methods used to combine high-dimensional, nonlinear dynamical models with observed data. Ensemble methods are indispensable tools in science and engineering and have enjoyed great success in geophysical sciences, because they allow for computationally cheap low-ensemble-state approximation for extremely high-dimensional turbulent forecast models. From a theoretical perspective, the dynamical properties of these methods are poorly understood. One of the central mysteries is the numerical phenomenon known as catastrophic filter divergence, whereby ensemble-state estimates explode to machine infinity, despite the true state remaining in a bounded region. In this article we provide a breakthrough insight into the phenomenon, by introducing a simple and natural forecast model that transparently exhibits catastrophic filter divergence under all ensemble methods and a large set of initializations. For this model, catastrophic filter divergence is not an artifact of numerical instability, but rather a true dynamical property of the filter. The divergence is not only validated numerically but also proven rigorously. The model cleanly illustrates mechanisms that give rise to catastrophic divergence and confirms intuitive accounts of the phenomena given in past literature.

  18. Concrete ensemble Kalman filters with rigorous catastrophic filter divergence

    Science.gov (United States)

    Kelly, David; Majda, Andrew J.; Tong, Xin T.

    2015-01-01

    The ensemble Kalman filter and ensemble square root filters are data assimilation methods used to combine high-dimensional, nonlinear dynamical models with observed data. Ensemble methods are indispensable tools in science and engineering and have enjoyed great success in geophysical sciences, because they allow for computationally cheap low-ensemble-state approximation for extremely high-dimensional turbulent forecast models. From a theoretical perspective, the dynamical properties of these methods are poorly understood. One of the central mysteries is the numerical phenomenon known as catastrophic filter divergence, whereby ensemble-state estimates explode to machine infinity, despite the true state remaining in a bounded region. In this article we provide a breakthrough insight into the phenomenon, by introducing a simple and natural forecast model that transparently exhibits catastrophic filter divergence under all ensemble methods and a large set of initializations. For this model, catastrophic filter divergence is not an artifact of numerical instability, but rather a true dynamical property of the filter. The divergence is not only validated numerically but also proven rigorously. The model cleanly illustrates mechanisms that give rise to catastrophic divergence and confirms intuitive accounts of the phenomena given in past literature. PMID:26261335

  19. e-FILTERS OF MS-ALGEBRAS

    Institute of Scientific and Technical Information of China (English)

    M.Sambasiva RAO

    2013-01-01

    The notion of e-filters is introduced in an MS-algebra and characterized.The concept of D-filters is introduced and a set of equivalent conditions under which every D-filter is an e-filter are given.The properties of the space of all prime e-filters of an MS-algebra are observed.The concept of D-prime filters is introduced and then a set of equivalent conditions are derived for a prime e-filter to become a D-prime filter in topological terms.

  20. Digital filtering: background and tutorial for psychophysiologists.

    Science.gov (United States)

    Cook, E W; Miller, G A

    1992-05-01

    Digital filtering offers more to psychophysiologists than is commonly appreciated. An introduction is offered here to foster the explicit design and use of digital filters. Because of considerable confusion in the literature about terminology important to both analog and digital filtering, basic concepts are reviewed and clarified. Because some time series concepts are fundamental to digital filtering, these are also presented. Examples of filters commonly used in psychophysiology are given, and procedures are presented for the design and use of one type of digital filter. Properties of some types of digital filters are described, and the relative advantages of simple analog and digital filters are discussed.

  1. Modeling Contamination Migration on the Chandra X-Ray Observatory - III

    Science.gov (United States)

    O'Dell, Stephen L.; Swartz, Douglas A.; Tice, Neil W.; Plucinsky, Paul P.; Grant, Catherine E.; Marshall, Herman L.; Vikhlinin, Alexy A.; Tennant, Allyn F.; Dahmer, Matthew T.

    2015-01-01

    During its first 16 years of operation, the cold (about -60 C) optical blocking filter of the Advanced CCD Imaging Spectrometer (ACIS), aboard the Chandra X-ray Observatory, has accumulated a growing layer of molecular contamination that attenuates low-energy x rays. Over the past few years, the accumulation rate, spatial distribution, and composition have changed. This evolution has motivated further analysis of contamination migration within and near the ACIS cavity, in part to evaluate potential bake-out scenarios intended to reduce the level of contamination. Keywords: X-ray astronomy, CCDs, contamination, modeling and simulation, spacecraft operations

  2. Failing arsenic mitigation technology in rural Bangladesh: explaining stagnation in niche formation of the Sono filter

    NARCIS (Netherlands)

    Kundu, D.K.; Mol, A.P.J.; Gupta, A.

    2016-01-01

    Arsenic contamination of shallow hand pump tube well drinking water in Bangladesh has created opportunities for radical innovations to emerge. One such innovation is the household Sono filter, designed to remove arsenic from water supplies. Applying a strategic niche management approach, and based

  3. Subsurface contaminants focus area

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-08-01

    The US Department of Enregy (DOE) Subsurface Contaminants Focus Area is developing technologies to address environmental problems associated with hazardous and radioactive contaminants in soil and groundwater that exist throughout the DOE complex, including radionuclides, heavy metals; and dense non-aqueous phase liquids (DNAPLs). More than 5,700 known DOE groundwater plumes have contaminated over 600 billion gallons of water and 200 million cubic meters of soil. Migration of these plumes threatens local and regional water sources, and in some cases has already adversely impacted off-site rsources. In addition, the Subsurface Contaminants Focus Area is responsible for supplying technologies for the remediation of numerous landfills at DOE facilities. These landfills are estimated to contain over 3 million cubic meters of radioactive and hazardous buried Technology developed within this specialty area will provide efective methods to contain contaminant plumes and new or alternative technologies for development of in situ technologies to minimize waste disposal costs and potential worker exposure by treating plumes in place. While addressing contaminant plumes emanating from DOE landfills, the Subsurface Contaminants Focus Area is also working to develop new or alternative technologies for the in situ stabilization, and nonintrusive characterization of these disposal sites.

  4. 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....

  5. 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...

  6. Biometric verification with correlation filters

    Science.gov (United States)

    Vijaya Kumar, B. V. K.; Savvides, Marios; Xie, Chunyan; Venkataramani, Krithika; Thornton, Jason; Mahalanobis, Abhijit

    2004-01-01

    Using biometrics for subject verification can significantly improve security over that of approaches based on passwords and personal identification numbers, both of which people tend to lose or forget. In biometric verification the system tries to match an input biometric (such as a fingerprint, face image, or iris image) to a stored biometric template. Thus correlation filter techniques are attractive candidates for the matching precision needed in biometric verification. In particular, advanced correlation filters, such as synthetic discriminant function filters, can offer very good matching performance in the presence of variability in these biometric images (e.g., facial expressions, illumination changes, etc.). We investigate the performance of advanced correlation filters for face, fingerprint, and iris biometric verification.

  7. 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).

  8. In-Place Filter Tester Instrument for Nuclear Material Containers.

    Science.gov (United States)

    Brown, Austin D; Moore, Murray E; Runnels, Joel T; Reeves, Kirk

    2016-05-01

    A portable instrument was developed to determine filter clogging and container leakage of in-place nuclear material storage canisters. This paper describes the development of an in-place filter tester for determining the "as found" condition of unopened canisters. The U.S. Department of Energy uses several thousand canisters for nuclear material storage, and air filters in the canister lids allow gases to escape while maintaining an equilibrated pressure without release of radioactive contamination. Diagnosing the filter condition and canister integrity is important for ensuring worker and public safety. Customized canister interfaces were developed for suction clamping (during tests) to two of the canister types in use at Los Alamos National Laboratory. Experimental leakage scenarios included: O-rings fouled with dust, cracked O-rings, and loose canister lids. The prototype tester has a measurement range for air leakage rates from 8.2 × 10 mL s up to 3.0 × 10 mL s. This is sufficient to measure a leak rate of 3.4 × 10 mL s, which is the Los Alamos helium leak criterion for post-drop tested canisters. The In-Place-Filter-Tester cannot measure to the lower value of the helium leak criterion for pre-drop tested canisters (1.0 × 10 mL s). However, helium leak testing requires canister disassembly, while the new in-place filter tester is able to assess the assembled condition of as-found and in-situ canisters.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, Ivan A.; Saveliev, Alexei V.; Rasipuram, Srinivasan; Kuznetsov, Andrey V.; Brown, Alan; Jasper, Warren [Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Textile Engineering Chemistry and Science, North Carolina State University, Raleigh, NC 27695 (United States)

    2012-05-15

    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).

  10. Stochastic processes and filtering theory

    CERN Document Server

    Jazwinski, Andrew H

    2007-01-01

    This unified treatment of linear and nonlinear filtering theory presents material previously available only in journals, and in terms accessible to engineering students. Its sole prerequisites are advanced calculus, the theory of ordinary differential equations, and matrix analysis. Although theory is emphasized, the text discusses numerous practical applications as well.Taking the state-space approach to filtering, this text models dynamical systems by finite-dimensional Markov processes, outputs of stochastic difference, and differential equations. Starting with background material on probab

  11. Aquatic Plants Aid Sewage Filter

    Science.gov (United States)

    Wolverton, B. C.

    1985-01-01

    Method of wastewater treatment combines micro-organisms and aquatic plant roots in filter bed. Treatment occurs as liquid flows up through system. Micro-organisms, attached themselves to rocky base material of filter, act in several steps to decompose organic matter in wastewater. Vascular aquatic plants (typically, reeds, rushes, cattails, or water hyacinths) absorb nitrogen, phosphorus, other nutrients, and heavy metals from water through finely divided roots.

  12. Performance analysis of adjustable window based FIR filter for noisy ECG Signal Filtering

    Directory of Open Access Journals (Sweden)

    N. Mahawar

    2013-09-01

    Full Text Available Recording of the electrical activity associated to heart functioning is known as Electrocardiogram (ECG. ECG is a quasi-periodical, rhythmically signal synchronized by the function of the heart, which acts as a generator of bioelectric events. ECG signals are low level signals and sensitive to external contaminations. Electrocardiogram signals are often corrupted by noise which may have electrical or electrophysiological origin. The noise signal tends to alter the signal morphology, thereby hindering the correct diagnosis. In order to remove the unwanted noise, a digital filtering technique based on adjustable windows is proposed in this paper. Finite Impulse Response (FIR low pass is designed using windowing method for the ECG signal. The results obtained from different techniques are compared on the basis of popularly used signal error measures like SNR, PRD, PRD1, and MSE.

  13. Q value analysis of microwave photonic filters

    Institute of Scientific and Technical Information of China (English)

    Lina ZHOU; Xinliang ZHANG; Enming XU

    2009-01-01

    This paper first presents the fundamental principles of the microwave photonic filters.As an example to explain how to implement a microwave photonic filter, a specific finite impulse response (FIR) filter is illustrated.Next, the Q value of the microwave photonic filters is analyzed theoretically, and methods around how to gain high Q value are discussed.Then,divided into FIR filter, first-order infinite impulse response (IIR) filter, and multi-order IIR filter, several novel microwave photonic filters with high Q value are listed and compared.The technical difficulties to get high Q value in first-order IIR filter and multi-order IIR filter are analyzed concretely.Finally, in order to gain higher Q value, a multi-order IIR microwave photonic filter that easily extends its order is presented and discussed.

  14. Stability Study of Filtering Techniques in Pictures of mini-MIAS Database; Estudio de Estabilidad de Tecnicas de Filtrado en Imagenes de la Base de Datos mini-MIAS

    Energy Technology Data Exchange (ETDEWEB)

    Parcero, E.; Vidal, V.; Verdu, G.; Mayo, P.

    2014-07-01

    The study of filtering techniques applied to medical imaging is particularly important because it can be decisive for an accurate diagnosis. This work aims to study the stability of Fuzzy Peer Group Averaging filter when applied to mammographic images of different nature in relation to the type of tissue abnormality found and diagnosis. The results show that the filter is effective, because obtained a PSNR value of 27 by comparing the filtered image with the original, and a value of 17 by comparing the filtered image with contaminated with noise. Also show that the filter will behave properly regardless of the image characteristics. (Author)

  15. Filtering algorithms using shiftable kernels

    CERN Document Server

    Chaudhury, Kunal Narayan

    2011-01-01

    It was recently demonstrated in [4][arxiv:1105.4204] that the non-linear bilateral filter \\cite{Tomasi} can be efficiently implemented using an O(1) or constant-time algorithm. At the heart of this algorithm was the idea of approximating the Gaussian range kernel of the bilateral filter using trigonometric functions. In this letter, we explain how the idea in [4] can be extended to few other linear and non-linear filters [18,21,2]. While some of these filters have received a lot of attention in recent years, they are known to be computationally intensive. To extend the idea in \\cite{Chaudhury2011}, we identify a central property of trigonometric functions, called shiftability, that allows us to exploit the redundancy inherent in the filtering operations. In particular, using shiftable kernels, we show how certain complex filtering can be reduced to simply that of computing the moving sum of a stack of images. Each image in the stack is obtained through an elementary pointwise transform of the input image. Thi...

  16. A taxonomy fuzzy filtering approach

    Directory of Open Access Journals (Sweden)

    Vrettos S.

    2003-01-01

    Full Text Available Our work proposes the use of topic taxonomies as part of a filtering language. Given a taxonomy, a classifier is trained for each one of its topics. The user is able to formulate logical rules combining the available topics, e.g. (Topic1 AND Topic2 OR Topic3, in order to filter related documents in a stream. Using the trained classifiers, every document in the stream is assigned a belief value of belonging to the topics of the filter. These belief values are then aggregated using logical operators to yield the belief to the filter. In our study, Support Vector Machines and Naïve Bayes classifiers were used to provide topic probabilities. Aggregation of topic probabilities based on fuzzy logic operators was found to improve filtering performance on the Renters text corpus, as compared to the use of their Boolean counterparts. Finally, we deployed a filtering system on the web using a sample taxonomy of the Open Directory Project.

  17. Biodegradation of gasoline compounds (BTEX) in a water works sand filter

    DEFF Research Database (Denmark)

    Arvin, Erik; Engelsen, P.; Sebber, U.

    2004-01-01

    Various chemical compounds including aromatic gasoline compounds frequently contaminate drinking water wells in urban areas. Because ground water treatment is simple, usually consisting of aeration/stripping and sand-filtration, it is of significant interest to know the ability of the conventional...... treatment to remove the chemical contaminants. The removal of gasoline compounds was investigated in a two-stage pilot scale sand filter, each with a filter depth of 0.8-1 m and with a filtration rate of 7.6 m/h. The concentrations of aromatic compounds were in the range 7-15 mu g/L, which are realistically...... sand grains). Influent iron concentrations in the range 0-4 mg/L and backwashing did not adversely affect the biodegradation of hydrocarbons. This study has shown that a conventional biological active sand filter can act as an efficient barrier against gasoline compounds, thereby saving the consumer...

  18. International journal of food contamination

    National Research Council Canada - National Science Library

    2014-01-01

    The International Journal of Food Contamination publishes baseline, monitoring data, indicating the qualitative and quantitative presence of microbiological and chemical contaminants in foods, animal...

  19. Radiological results for samples collected on paired glass- and cellulose-fiber filters at the Sandia complex, Tonopah Test Range, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Mizell, Steve A. [Desert Research Inst. (DRI), Las Vegas, NV (United States); Shadel, Craig A. [Desert Research Inst. (DRI), Las Vegas, NV (United States)

    2016-03-01

    Airborne particulates are collected at U.S. Department of Energy sites that exhibit radiological contamination on the soil surface to help assess the potential for wind to transport radionuclides from the contamination sites. Collecting these samples was originally accomplished by drawing air through a cellulose-fiber filter. These filters were replaced with glass-fiber filters in March 2011. Airborne particulates were collected side by side on the two filter materials between May 2013 and May 2014. Comparisons of the sample mass and the radioactivity determinations for the side-by-side samples were undertaken to determine if the change in the filter medium produced significant results. The differences in the results obtained using the two filter types were assessed visually by evaluating the time series and correlation plots and statistically by conducting a nonparametric matched-pair sign test. Generally, the glass-fiber filters collect larger samples of particulates and produce higher radioactivity values for the gross alpha, gross beta, and gamma spectroscopy analyses. However, the correlation between the radioanalytical results for the glass-fiber filters and the cellulose-fiber filters was not strong enough to generate a linear regression function to estimate the glass-fiber filter sample results from the cellulose-fiber filter sample results.

  20. Simplified Method for Groundwater Treatment Using Dilution and Ceramic Filter

    Science.gov (United States)

    Musa, S.; Ariff, N. A.; Kadir, M. N. Abdul; Denan, F.

    2016-07-01

    Groundwater is one of the natural resources that is not susceptible to pollutants. However, increasing activities of municipal, industrial, agricultural or extreme land use activities have resulted in groundwater contamination as occured at the Research Centre for Soft Soil Malaysia (RECESS), Universiti Tun Hussein Onn Malaysia (UTHM). Thus, aims of this study is to treat groundwater by using rainwater and simple ceramic filter as a treatment agent. The treatment uses rain water dilution, ceramic filters and combined method of dilute and filtering as an alternate treatment which are simple and more practical compared to modern or chemical methods. The water went through dilution treatment processes able to get rid of 57% reduction compared to initial condition. Meanwhile, the water that passes through the filtering process successfully get rid of as much as 86% groundwater parameters where only chloride does not pass the standard. Favorable results for the combination methods of dilution and filtration methods that can succesfully eliminate 100% parameters that donot pass the standards of the Ministry of Health and the Interim National Drinking Water Quality Standard such as those found in groundwater in RECESS, UTHM especially sulfate and chloride. As a result, it allows the raw water that will use clean drinking water and safe. It also proves that the method used in this study is very effective in improving the quality of groundwater.

  1. Biotreatment of air containing triethylamine (TEA vapor in biotrickling filter

    Directory of Open Access Journals (Sweden)

    A. Safari Variani

    2015-08-01

    Full Text Available Background: Treatment of waste air containing volatile organic compounds (VOCs using cheap and environmentally friendly methods is one of active fields in air pollution control. Objective: The aim of this study was to treat air containing triethylamine (TEA vapor using biotrickling filter inoculated with microbial species decomposing TEA. Methods: This experimental study was conducted in the School of Health affiliated to Qazvin University of Medical Sciences in 2014. Biotreatment was performed with biotrickling filter inoculated with microbial species decomposing TEA for two months. The biotrickling filter was set up with air containing TEA as the sole source of carbon, at Empty Bed Residence Times (EBRT of 36 sec, and inlet concentration of 84 ppm. Data were analyzed using descriptive statistics. Findings: Treatment of TEA contaminated air was made after an adaptation period of 11 days. Despite an increase in mass loading to 111 g/m3/h, TEA was eliminated with 109 g/m3/h capacity and 94-100% removal efficiency by zero order kinetics.Elimination capacity and removal efficiency were close to each other and confirmed109 g/m3/h as loading region with critical elimination capacity. Conclusion: With regards to the results, it is possible to treat air containing TEA vapor in biotrickling filter.

  2. Three Filtered Vacuum Arc Plasma Sources Deposition & Implantation System

    Institute of Scientific and Technical Information of China (English)

    WU Xian-ying; ZHANG Hui-xing; LI Qiang

    2004-01-01

    A deposition & implantation system, which includes three filtered vacuum arc plasma sources, has been built. Vacuum arc discharge is used to produce high-density metal plasma; Curved magnetic filtering technique is used to transfer the plasma into out-of-sight vacuum chamber and reduce macro-particles from the vacuum arc plasma in order to drastically reduce the macro-particles contamination of the films. The up to 30 kV negative bias applied to the target can be used for ion implantation in order to improve the film adhesion; or for ion sputtering to clear the substrate surface. The 0 to 300 V negative bias can be used to adjust the ion energy which forming films. The system is designed for various thin films synthesizing, such as single-layer, compound layer, multi-layer films. It's principle, components and applications are described in the literature.

  3. MULTISCALE TENSOR ANISOTROPIC FILTERING OF FLUORESCENCE MICROSCOPY FOR DENOISING MICROVASCULATURE.

    Science.gov (United States)

    Prasath, V B S; Pelapur, R; Glinskii, O V; Glinsky, V V; Huxley, V H; Palaniappan, K

    2015-04-01

    Fluorescence microscopy images are contaminated by noise and improving image quality without blurring vascular structures by filtering is an important step in automatic image analysis. The application of interest here is to automatically extract the structural components of the microvascular system with accuracy from images acquired by fluorescence microscopy. A robust denoising process is necessary in order to extract accurate vascular morphology information. For this purpose, we propose a multiscale tensor with anisotropic diffusion model which progressively and adaptively updates the amount of smoothing while preserving vessel boundaries accurately. Based on a coherency enhancing flow with planar confidence measure and fused 3D structure information, our method integrates multiple scales for microvasculature preservation and noise removal membrane structures. Experimental results on simulated synthetic images and epifluorescence images show the advantage of our improvement over other related diffusion filters. We further show that the proposed multiscale integration approach improves denoising accuracy of different tensor diffusion methods to obtain better microvasculature segmentation.

  4. 3D filtering technique in presence of additive noise in color videos implemented on DSP

    Science.gov (United States)

    Ponomaryov, Volodymyr I.; Montenegro-Monroy, Hector; Palacios, Alfredo

    2014-05-01

    A filtering method for color videos contaminated by additive noise is presented. The proposed framework employs three filtering stages: spatial similarity filtering, neighboring frame denoising, and spatial post-processing smoothing. The difference with other state-of- the-art filtering methods, is that this approach, based on fuzzy logic, analyses basic and related gradient values between neighboring pixels into a 7 fi 7 sliding window in the vicinity of a central pixel in each of the RGB channels. Following, the similarity measures between the analogous pixels in the color bands are taken into account during the denoising. Next, two neighboring video frames are analyzed together estimating local motions between the frames using block matching procedure. In the final stage, the edges and smoothed areas are processed differently in a current frame during the post-processing filtering. Numerous simulations results confirm that this 3D fuzzy filter perform better than other state-of-the- art methods, such as: 3D-LLMMSE, WMVCE, RFMDAF, FDARTF G, VBM3D and NLM, in terms of objective criteria (PSNR, MAE, NCD and SSIM) as well as subjective perception via human vision system in the different color videos. An efficiency analysis of the designed and other mentioned filters have been performed on the DSPs TMS320 DM642 and TMS320DM648 by Texas Instruments through MATLAB and Simulink module showing that the novel 3D fuzzy filter can be used in real-time processing applications.

  5. Granular-bed and ceramic candle filters in commercial plants: A comparison

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, K.B.; Haas, J.C.; Eshelman, M.B.

    1993-04-01

    Advanced coal fired power cycles require the removal of coal ash at high temperature and pressure. Granular-bed and ceramic candle filters can be used for this service. Conceptual designs for commercial size applications are made for each type of filter. The filters are incorporated in the design of a Foster Wheeler 450 MWe second generation pressurized fluidized bed combustion plant which contains a pressurized fluidized combustor and carbonizer. In a second application, the inters are incorporated in the design of a 100 MWe KRW (air) gasifier based power plant. The candle filter design is state of the art as determined from the open literature with an effort to minimize the cost. The granular-bed filter design is based on test work performed at high temperature and low pressure, tests at New York University performed at high pressure and temperate, and new analysis used to simplify the scale up of the filter and reduce overall cost. The incorporation of chemically reactive granites in the granular-bed filter for the removal of additional coal derived contaminants such as alkali or sulfur is considered. The conceptual designs of the granular-bed inter and the ceramic candle filter are compared in terms of the cost of electricity, capital cost, and operating and maintenance costs for each application.

  6. Anti-airborne-molecular-contamination technology in clean rooms; Kukichu no kagaku osen no teigen taisaku

    Energy Technology Data Exchange (ETDEWEB)

    Sakata, S.; Sato, K.; Takahashi, H.; Okada, T.

    1998-07-31

    As for, countermeasures for chemical contaminants in a cleanroom air, the technical development has progressed earnestly since T top phenomenon of photo-amplified resist with basic gas due to atmosphere was pointed out in 1991 by MacDonald. Airborne-Molecular-Contamination (AMC) is classified into acids, bases, condensables, and dopants. According to SEMATECH no 95052812A-TR, condensable are defined as silicones or hydrocarbons with a boiling point greater than or equal to 150 degC. Water-soluble gaseous contaminants in outdoor air coming into cleanrooms are removed with a water spray equipment. AMC originated from circulating air in cleanrooms are prevented using various chemical filters. Conventional chemical filters made of activated charcoal, however, have several defects. Ceramic chemical filters developed by the authors are nonflammable, and consist of inorganic materials without any volatile organic matters and without alkaline metal and so on, and they have high removal efficiencies of condensable. 15 refs., 12 figs., 3 tabs.

  7. Direct quantification of airborne nanoparticles composition by TXRF after collection on filters

    Energy Technology Data Exchange (ETDEWEB)

    Motellier, S; Lhaute, K; Guiot, A; Golanski, L; Tardif, F [CEA Grenoble, DRT, LITEN, DTNM, Laboratory of Nanochemistry and Nanosafety, 17 Avenue des Martyrs, Cedex 9, F-38054 Grenoble (France); Geoffroy, C, E-mail: sylvie.motellier@cea.fr [Elexience, 9 rue des petits ruisseaux, BP 61, 91371 Verrieres-le-Buisson Cedex (France)

    2011-07-06

    Direct TXRF analysis of nanoparticles deposited on filters was evaluated. Standard filters spiked with known amounts of NP were produced using an atomizer which generates an aerosol from a NP containing-liquid suspension. Polycarbonate filters provided the highest fluorescence signals and black polycarbonate filters containing chromium were further selected, Cr being used as internal standard for elemental quantification of the filter contaminants. Calibration curves were established for various NP (TiO{sub 2}, ZnO, CeO{sub 2}, Al{sub 2}O{sub 3}). Good linearity was observed. Low limits of detection were in the tens to the hundreds of ngs per filter, the method being less adapted to Al{sub 2}O{sub 3} due to the poor TXRF sensitivity for light elements. The analysis of MW-CNTs was attempted by quantification of their metal (Fe) catalyst impurities. Problems like CNT dispersion in liquids, quantification of the deposited quantity and high Fe-background contamination.

  8. Contamination vs. Exposure

    Science.gov (United States)

    ... Issues Related to Polonium-210 Contamination in the United Kingdom Guidance for Public Health Departments and Clinicians Caring ... released into the environment can cause air, water, surfaces, soil, plants, buildings, people, or animals to become ...

  9. Contaminant Candidate List 3

    Data.gov (United States)

    U.S. Environmental Protection Agency — CCL 3 is a list of contaminants that are currently not subject to any proposed or promulgated national primary drinking water regulations, that are known or...

  10. Contaminant Candidate List 1

    Data.gov (United States)

    U.S. Environmental Protection Agency — CCL 1 is a list of contaminants that are currently not subject to any proposed or promulgated national primary drinking water regulations, that are known or...

  11. Contaminant Candidate List 2

    Data.gov (United States)

    U.S. Environmental Protection Agency — CCL 2 is a list of contaminants that are currently not subject to any proposed or promulgated national primary drinking water regulations, that are known or...

  12. Identifying fecal matter contamination in produce fields using multispectral reflectance imaging under ambient solar illumination

    Science.gov (United States)

    Everard, Colm D.; Kim, Moon S.; Lee, Hoonsoo; O'Donnell, Colm P.

    2016-05-01

    An imaging device to detect fecal contamination in fresh produce fields could allow the producer avoid harvesting fecal contaminated produce. E.coli O157:H7 outbreaks have been associated with fecal contaminated leafy greens. In this study, in-field spectral profiles of bovine fecal matter, soil, and spinach leaves are compared. A common aperture imager designed with two identical monochromatic cameras, a beam splitter, and optical filters was used to simultaneously capture two-spectral images of leaves contaminated with both fecal matter and soil. The optical filters where 10 nm full width half maximum bandpass filters, one at 690 nm and the second at 710 nm. These were mounted in front of the object lenses. New images were created using the ratio of these two spectral images on a pixel by pixel basis. Image analysis results showed that the fecal matter contamination could be distinguished from soil and leaf on the ratio images. The use of this technology has potential to allow detection of fecal contamination in produce fields which can be a source of foodbourne illnesses. It has the added benefit of mitigating cross-contamination during harvesting and processing.

  13. Modeling for Airborne Contamination

    Energy Technology Data Exchange (ETDEWEB)

    F.R. Faillace; Y. Yuan

    2000-08-31

    The objective of Modeling for Airborne Contamination (referred to from now on as ''this report'') is to provide a documented methodology, along with supporting information, for estimating the release, transport, and assessment of dose to workers from airborne radioactive contaminants within the Monitored Geologic Repository (MGR) subsurface during the pre-closure period. Specifically, this report provides engineers and scientists with methodologies for estimating how concentrations of contaminants might be distributed in the air and on the drift surfaces if released from waste packages inside the repository. This report also provides dose conversion factors for inhalation, air submersion, and ground exposure pathways used to derive doses to potentially exposed subsurface workers. The scope of this report is limited to radiological contaminants (particulate, volatile and gaseous) resulting from waste package leaks (if any) and surface contamination and their transport processes. Neutron activation of air, dust in the air and the rock walls of the drift during the preclosure time is not considered within the scope of this report. Any neutrons causing such activation are not themselves considered to be ''contaminants'' released from the waste package. This report: (1) Documents mathematical models and model parameters for evaluating airborne contaminant transport within the MGR subsurface; and (2) Provides tables of dose conversion factors for inhalation, air submersion, and ground exposure pathways for important radionuclides. The dose conversion factors for air submersion and ground exposure pathways are further limited to drift diameters of 7.62 m and 5.5 m, corresponding to the main and emplacement drifts, respectively. If the final repository design significantly deviates from these drift dimensions, the results in this report may require revision. The dose conversion factors are further derived by using concrete of

  14. Evaluating document filtering systems over time

    NARCIS (Netherlands)

    Kenter, T.; Balog, K.; de Rijke, M.

    2015-01-01

    Document filtering is a popular task in information retrieval. A stream of documents arriving over time is filtered for documents relevant to a set of topics. The distinguishing feature of document filtering is the temporal aspect introduced by the stream of documents. Document filtering systems, up

  15. CPHD filter derivation for extended targets

    CERN Document Server

    Orguner, Umut

    2010-01-01

    This document derives the CPHD filter for extended targets. Only the update step is derived here. Target generated measurements, false alarms and prior are all assumed to be independent identically distributed cluster processes. We also prove here that the derived CPHD filter for extended targets reduce to PHD filter for extended targets and CPHD filter for standard targets under suitable assumptions.

  16. Band-pass filtered velocity statistics in decaying turbulent box

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    For homogeneous isotropic turbulence study,the acquisition of band-pass filtered velocity increments(FVI) in a non-forced turbulent box is still a challenge both experimentally and numerically.Turbulence and associated physical processes,at a given instant,are permanently contaminated by a forcing process which can seldom be universal.The situation tends to be the origin of intermittency and the non-Gaussian probability density distribution for acceleration and velocity gradients.To reveal implied mechanism...

  17. Performance-Based Technology Selection Filter description report

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, M.C.; Morrison, J.L.; Morneau, R.A.; Rudin, M.J.; Richardson, J.G.

    1992-05-01

    A formal methodology has been developed for identifying technology gaps and assessing innovative or postulated technologies for inclusion in proposed Buried Waste Integrated Demonstration (BWID) remediation systems. Called the Performance-Based Technology Selection Filter, the methodology provides a formalized selection process where technologies and systems are rated and assessments made based on performance measures, and regulatory and technical requirements. The results are auditable, and can be validated with field data. This analysis methodology will be applied to the remedial action of transuranic contaminated waste pits and trenches buried at the Idaho National Engineering Laboratory (INEL).

  18. Advances in the understanding of low molecular weight silicon formation and implications for control by AMC filters

    Science.gov (United States)

    Lobert, Jürgen M.; Cate, Philip W.; Ruede, David J.; Wildgoose, Joseph R.; Miller, Charles M.; Gaudreau, John C.

    2010-03-01

    Trimethylsilanol (TMS) is a low molecular weight / low boiling point silicon-containing, airborne contaminant that has received increased interest over the past few years as an important cause for contamination of optical surfaces in lithography equipment. TMS is not captured well by carbon-based filters, and hexamethyldisiloxane (HMDSO), even though captured well, can be converted to TMS when using acidic filter media commonly used for ammonia removal. TMS and HMDSO co-exist in a chemical equilibrium, which is affected by the acidity and moisture of their environment. This publication shows that HMDSO is converted to TMS by acidic media at concentrations typically found in cleanroom environments. This is contrary to published results that show a re-combination of TMS to HMDSO on acid media. We also demonstrate that, based on its conversion to TMS, HMDSO is not a suitable test compound for hybrid chemical filter performance, as the apparent lifetime/capacity of the filter can be substantially skewed towards larger numbers when conversion to TMS is involved. We show lifetime test results with toluene and HMDSO on acidic and non-acidic filter media. Appropriately designed, asymmetric hybrid chemical filters significantly minimize or eliminate the conversion of HMDSO to TMS, thereby reducing the risk to scanner optical elements. Similarly, such filters can also prevent or reduce acid-sensitive reactions of other AMC when passing through filter systems.

  19. Filter transient response to EEG waveforms.

    Science.gov (United States)

    Shirakawa, S; Smith, J R; Azumi, K

    1987-01-01

    The response of two types of linear filters to sinusoidal bursts was calculated to demonstrate how filters can distort EEG waveforms. Results show that the wider the filter bandwidth the less is the distortion, and for a given bandwidth, the higher the filter order the greater the distortion. The response of a linear phase filter was also calculated to demonstrate that this type of filter can also cause waveform distortion, although it is normally less than that caused by Butterworth, Tchebychev and elliptic filters.

  20. Novel Simplex Unscented Transform and Filter

    Institute of Scientific and Technical Information of China (English)

    Wan-Chun Li; Ping Wei; Xian-Ci Xiao

    2008-01-01

    In this paper, a new simplex unscented transform (UT) based Schmidt orthogonal algorithm and a new filter method based on this transform are proposed. This filter has less computation consumption than UKF (unscented Kalman filter), SUKF (simplex unscented Kalman filter) and EKF (extended Kalman filter). Computer simulation shows that this filter has the same performance as UKF and SUKF, and according to the analysis of the computational requirements of EKF, UKF and SUKF, this filter has preferable practicality value. Finally, the appendix shows the efficiency for this UT.

  1. Digital notch filter based active damping for LCL filters

    DEFF Research Database (Denmark)

    Yao, Wenli; Yang, Yongheng; Zhang, Xiaobin

    2015-01-01

    . In contrast, the active damping does not require any dissipation elements, and thus has become of increasing interest. As a result, a vast of active damping solutions have been reported, among which multi-loop control systems and additional sensors are necessary, leading to increased cost and complexity....... In this paper, a notch filter based active damping without the requirement of additional sensors is proposed, where the inverter current is employed as the feedback variable. Firstly, a design method of the notch filter for active damping is presented. The entire system stability has then been investigated...... in the z-domain. Simulations and experiments are carried out to verify the proposed active damping method. Both results have confirmed that the notch filter based active damping can ensure the entire system stability in the case of resonances with a good system performance....

  2. Numerical simulation of large fabric filter

    Directory of Open Access Journals (Sweden)

    Kovařík Petr

    2012-04-01

    Full Text Available Fabric filters are used in the wide range of industrial technologies for cleaning of incoming or exhaust gases. To achieve maximal efficiency of the discrete phase separation and long lifetime of the filter hoses, it is necessary to ensure uniform load on filter surface and to avoid impacts of heavy particles with high velocities to the filter hoses. The paper deals with numerical simulation of two phase flow field in a large fabric filter. The filter is composed of six chambers with approx. 1600 filter hoses in total. The model was simplified to one half of the filter, the filter hoses walls were substituted by porous zones. The model settings were based on experimental data, especially on the filter pressure drop. Unsteady simulations with different turbulence models were done. Flow field together with particles trajectories were analyzed. The results were compared with experimental observations.

  3. Numerical simulation of large fabric filter

    Science.gov (United States)

    Sedláček, Jan; Kovařík, Petr

    2012-04-01

    Fabric filters are used in the wide range of industrial technologies for cleaning of incoming or exhaust gases. To achieve maximal efficiency of the discrete phase separation and long lifetime of the filter hoses, it is necessary to ensure uniform load on filter surface and to avoid impacts of heavy particles with high velocities to the filter hoses. The paper deals with numerical simulation of two phase flow field in a large fabric filter. The filter is composed of six chambers with approx. 1600 filter hoses in total. The model was simplified to one half of the filter, the filter hoses walls were substituted by porous zones. The model settings were based on experimental data, especially on the filter pressure drop. Unsteady simulations with different turbulence models were done. Flow field together with particles trajectories were analyzed. The results were compared with experimental observations.

  4. Shielded multi-stage EMI noise filter

    Energy Technology Data Exchange (ETDEWEB)

    Kisner, Roger Allen; Fugate, David Lee

    2016-11-08

    Electromagnetic interference (EMI) noise filter embodiments and methods for filtering are provided herein. EMI noise filters include multiple signal exclusion enclosures. The multiple signal exclusion enclosures contain filter circuit stages. The signal exclusion enclosures can attenuate noise generated external to the enclosures and/or isolate noise currents generated by the corresponding filter circuits within the enclosures. In certain embodiments, an output of one filter circuit stage is connected to an input of the next filter circuit stage. The multiple signal exclusion enclosures can be chambers formed using conductive partitions to divide an outer signal exclusion enclosure. EMI noise filters can also include mechanisms to maintain the components of the filter circuit stages at a consistent temperature. For example, a metal base plate can distribute heat among filter components, and an insulating material can be positioned inside signal exclusion enclosures.

  5. Shielded multi-stage EMI noise filter

    Science.gov (United States)

    Kisner, Roger Allen; Fugate, David Lee

    2016-11-08

    Electromagnetic interference (EMI) noise filter embodiments and methods for filtering are provided herein. EMI noise filters include multiple signal exclusion enclosures. The multiple signal exclusion enclosures contain filter circuit stages. The signal exclusion enclosures can attenuate noise generated external to the enclosures and/or isolate noise currents generated by the corresponding filter circuits within the enclosures. In certain embodiments, an output of one filter circuit stage is connected to an input of the next filter circuit stage. The multiple signal exclusion enclosures can be chambers formed using conductive partitions to divide an outer signal exclusion enclosure. EMI noise filters can also include mechanisms to maintain the components of the filter circuit stages at a consistent temperature. For example, a metal base plate can distribute heat among filter components, and an insulating material can be positioned inside signal exclusion enclosures.

  6. Control of microbial contamination in drinking water from microfiltering dispensers by dialysis ultrafilters

    Directory of Open Access Journals (Sweden)

    Bolelli Luca

    2016-12-01

    Full Text Available Tap water filtering devices are widely employed to improve odor and taste of tap water, or to obtain refrigerated or sparkling drinking water. The presence of disinfectants-resistant bacteria in tap water is responsible of the biofilm formation inside tubes and tanks. The consequent contamination of dispensed water is a well-known hygiene problem because of the quite constant presence of potentially pathogenic bacteria likes P. aeruginosa. In this study, we tested the technical feasibility and effectiveness of the addition to different commercial devices of a packaged polysulphone fibers filter. We aimed to find a simple solution to implement the quality of the delivered water. Water contamination levels were determined in a wide selection of microfiltered water dispensers and we selected among them a representative group of 10 devices, new or in use. The packaged ultrafilter was introduced in about half of them, to monitor, when possible, in parallel the contamination levels and flow rate of a couple of identical units, with and without the filter. The placement of the dialysis filters resulted feasible at different positions along the water circuits of the variously designed filtration units. Delivered water resulted completely free from bacteria when the filter was placed exactly at, or very close to, the outlet in spite of the inner surfaces contamination. This performance was not obtained in presence of a more or less long tract of water circuits downstream the ultrafilter: a significant but not complete reduction of the plate count numbers was observed. The filters worked in continue over the whole study period, ten months, showing exactly the same efficiency. Moreover, the flow rate in presence of the filter was quite unaffected. The addition of this kind of filter to already in use water dispensers was technically easy, and its use can be recommended in all cases a simple but reliable water sanitization is requested.

  7. 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)

  8. A biological oil adsorption filter.

    Science.gov (United States)

    Pasila, Antti

    2004-12-01

    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.

  9. GPU Accelerated Vector Median Filter

    Science.gov (United States)

    Aras, Rifat; Shen, Yuzhong

    2011-01-01

    Noise reduction is an important step for most image processing tasks. For three channel color images, a widely used technique is vector median filter in which color values of pixels are treated as 3-component vectors. Vector median filters are computationally expensive; for a window size of n x n, each of the n(sup 2) vectors has to be compared with other n(sup 2) - 1 vectors in distances. General purpose computation on graphics processing units (GPUs) is the paradigm of utilizing high-performance many-core GPU architectures for computation tasks that are normally handled by CPUs. In this work. NVIDIA's Compute Unified Device Architecture (CUDA) paradigm is used to accelerate vector median filtering. which has to the best of our knowledge never been done before. The performance of GPU accelerated vector median filter is compared to that of the CPU and MPI-based versions for different image and window sizes, Initial findings of the study showed 100x improvement of performance of vector median filter implementation on GPUs over CPU implementations and further speed-up is expected after more extensive optimizations of the GPU algorithm .

  10. Automated Integrated Analog Filter Design Issues

    OpenAIRE

    2015-01-01

    An analysis of modern automated integrated analog circuits design methods and their use in integrated filter design is done. Current modern analog circuits automated tools are based on optimization algorithms and/or new circuit generation methods. Most automated integrated filter design methods are only suited to gmC and switched current filter topologies. Here, an algorithm for an active RC integrated filter design is proposed, that can be used in automated filter designs. The algorithm is t...

  11. Optimal Nonlinear Filter for INS Alignment

    Institute of Scientific and Technical Information of China (English)

    赵瑞; 顾启泰

    2002-01-01

    All the methods to handle the inertial navigation system (INS) alignment were sub-optimal in the past. In this paper, particle filtering (PF) as an optimal method is used for solving the problem of INS alignment. A sub-optimal two-step filtering algorithm is presented to improve the real-time performance of PF. The approach combines particle filtering with Kalman filtering (KF). Simulation results illustrate the superior performance of these approaches when compared with extended Kalman filtering (EKF).

  12. Multiplier-free filters for wideband SAR

    DEFF Research Database (Denmark)

    Dall, Jørgen; Christensen, Erik Lintz

    2001-01-01

    This paper derives a set of parameters to be optimized when designing filters for digital demodulation and range prefiltering in SAR systems. Aiming at an implementation in field programmable gate arrays (FPGAs), an approach for the design of multiplier-free filters is outlined. Design results ar...... are presented in terms of filter complexity and performance. One filter has been coded in VHDL and preliminary results indicate that the filter can meet a 2 GHz input sample rate....

  13. Evolving Information Filtering for Personalized Information Service

    Institute of Scientific and Technical Information of China (English)

    田范江; 李丛蓉; 王鼎兴

    2001-01-01

    Information filtering (IF) systems are important for personalized information service. However, most current IF systems suffer from low quality and long training time. In this paper, a refined evolving information filtering method is presented. This method describes user's information need from multi-aspects and improves filtering quality through a process like natural selection. Experimental result shows this method can shorten training time, improve filtering quality, and reduce the relevance between filtering results and training sequence.

  14. Characterization of radioactive contaminants and water treatment trials for the Taiwan Research Reactor's spent fuel pool.

    Science.gov (United States)

    Huang, Chun-Ping; Lin, Tzung-Yi; Chiao, Ling-Huan; Chen, Hong-Bin

    2012-09-30

    There were approximately 926 m(3) of water contaminated by fission products and actinides in the Taiwan Research Reactor's spent fuel pool (TRR SFP). The solid and ionic contaminants were thoroughly characterized using radiochemical analyses, scanning electron microscopy equipped with an energy dispersive spectrometer (SEM-EDS), and inductively coupled plasma optical emission spectrometry (ICP-OES) in this study. The sludge was made up of agglomerates contaminated by spent fuel particles. Suspended solids from spent ion-exchange resins interfered with the clarity of the water. In addition, the ionic radionuclides such as (137)Cs, (90)Sr, U, and α-emitters, present in the water were measured. Various filters and cation-exchange resins were employed for water treatment trials, and the results indicated that the solid and ionic contaminants could be effectively removed through the use of filters and cation exchange resins, respectively. Interestingly, the removal of U was obviously efficient by cation exchange resin, and the ceramic depth filter composed of diatomite exhibited the properties of both filtration and adsorption. It was found that the ceramic depth filter could adsorb β-emitters, α-emitters, and uranium ions. The diatomite-based ceramic depth filter was able to simultaneously eliminate particles and adsorb ionic radionuclides from water.

  15. Inferior vena cava filters in cancer patients: to filter or not to filter

    Directory of Open Access Journals (Sweden)

    Hikmat Abdel-Razeq

    2011-03-01

    Full Text Available Hikmat Abdel-Razeq1, Asem Mansour2, Yousef Ismael1, Hazem Abdulelah11Department of Internal Medicine, 2Department of Radiology, King Hussein Cancer Center, Amman, JordanPurpose: Cancer and its treatment are recognized risk factors for venous thromboembolism (VTE; active cancer accounts for almost 20% of all newly diagnosed VTE. Inferior vena cava (IVC filters are utilized to provide mechanical thromboprophylaxis to prevent pulmonary embolism (PE or to avoid bleeding from systemic anticoagulation in high-risk situations. In this report, and utilizing a case study, we will address the appropriate utilization of such filters in cancer patients.Methods: The case of a 43-year-old female patient with rectal cancer, who developed deep vein thrombosis following a complicated medical course, will be presented. The patient was anticoagulated with a low molecular weight heparin, but a few months later and following an episode of bleeding, an IVC filter was planned. Using the PubMed database, articles published in English language addressing issues related to IVC filters in cancer patients were accessed and will be presented.Results: Many recent studies questioned the need to insert IVC filters in advanced-stage cancer patients, particularly those whose anticipated survival is short and prevention of PE may be of little clinical benefit and could be a poor utilization of resources.Conclusion: Systemic anticoagulation can be safely offered for the majority of cancer patients. When the risk of bleeding or pulmonary embolism is high, IVC filters can be utilized. However, placement of such filters should take into consideration the stage of disease and life expectancy of such patients.Keywords: anticoagulation, bleeding, chemotherapy

  16. The Effect of Different Boiling and Filtering Devices on the Concentration of Disinfection By-Products in Tap Water

    OpenAIRE

    Glòria Carrasco-Turigas; Villanueva, Cristina M.; Fernando Goñi; Panu Rantakokko; Nieuwenhuijsen, Mark J.

    2013-01-01

    Disinfection by-products (DBPs) are ubiquitous contaminants in tap drinking water with the potential to produce adverse health effects. Filtering and boiling tap water can lead to changes in the DBP concentrations and modify the exposure through ingestion. Changes in the concentration of 4 individual trihalomethanes (THM4) (chloroform (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and bromoform (TBM)), MX, and bromate were tested when boiling and filtering high bromine-conta...

  17. Mecoprop (MCPP) removal in full-scale rapid sand filters at a groundwater-based waterworks

    DEFF Research Database (Denmark)

    Hedegaard, Mathilde Jørgensen; Arvin, Erik; Corfitzen, Charlotte B.;

    2014-01-01

    Contamination by the herbicide mecoprop (MCPP) was detected in groundwater abstraction wells at Kerteminde Waterworks in concentrations up to 0.08μg/L. MCPP was removed to below detection limit in a simple treatment line where anaerobic groundwater was aerated and subsequently filtered by primary...... filters, MCPP concentration decreased from 0.037μg/L to below the detection limit of 0.01μg/L. MCPP was removed continuously at different filter depths (0.80m).Additionally, biodegradation, mineralisation and adsorption were investigated in the laboratory in order to elucidate removal mechanisms.......It was concluded that MCPP was removed in secondary rapid sand filters at Kerteminde Waterworks, to which both adsorption and microbial degradation contributed....

  18. Sensory pollution from bag-type fiberglass ventilation filters: Conventional filter compared with filters containing various amounts of activated carbon

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Fadeyi, M.O.; Clausen, Geo

    2009-01-01

    (100 g/m(2)). Each filter was weighed at the beginning of the soiling period and after 3 and 6 months of service. Additionally, up- and down-stream ozone concentrations and filter pressure drops were measured monthly. Following 6 months of service, the air downstream of each of the combination filters......As ventilation filters accumulate particles removed from the airstream, they become emitters of sensory pollutants that degrade indoor air quality. Previously we demonstrated that an F7 bag-type filter that incorporates activated carbon (a "combination filter") reduces this adverse effect compared...... to an equivalent filter without carbon. The aim of the present study was to examine how the amount of activated carbon (AC) used in combination filters affects their ability to remove both sensory offending pollutants and ozone. A panel evaluated the air downstream of four different filters after each had...

  19. Design of SVD/SGK Convolution Filters for Image Processing

    Science.gov (United States)

    1980-01-01

    of filters by transforming one-dimensional linear phase filters * into two-dimensional linear phase filters . By assuming that the prototype filter is a...linear phase filter , his algorithm transforms a one-dimensional filter h(u) into a two-dimensional filter W (u,v) by means of transformation given by...significance of their implementation of the designed filter is that a large two-dimensional convolution *A linear phase filter implies symmetry of the filter. 13

  20. Radiant zone heated particulate filter

    Science.gov (United States)

    Gonze, Eugene V [Pinckney, MI

    2011-12-27

    A system includes a particulate matter (PM) filter including an upstream end for receiving exhaust gas and a downstream end. A radiant zoned heater includes N zones, where N is an integer greater than one, wherein each of the N zones includes M sub-zones, where M is an integer greater than or equal to one. A control module selectively activates at least a selected one of the N zones to initiate regeneration in downstream portions of the PM filter from the one of the N zones, restricts exhaust gas flow in a portion of the PM filter that corresponds to the selected one of the N zones, and deactivates non-selected ones of the N zones.

  1. Quantum Diffusion, Measurement and Filtering

    CERN Document Server

    Belavkin, V P

    1993-01-01

    A brief presentation of the basic concepts in quantum probability theory is given in comparison to the classical one. The notion of quantum white noise, its explicit representation in Fock space, and necessary results of noncommutative stochastic analysis and integration are outlined. Algebraic differential equations that unify the quantum non Markovian diffusion with continuous non demolition observation are derived. A stochastic equation of quantum diffusion filtering generalising the classical Markov filtering equation to the quantum flows over arbitrary *-algebra is obtained. A Gaussian quantum diffusion with one dimensional continuous observation is considered.The a posteriori quantum state difusion in this case is reduced to a linear quantum stochastic filter equation of Kalman-Bucy type and to the operator Riccati equation for quantum correlations. An example of continuous nondemolition observation of the coordinate of a free quantum particle is considered, describing a continuous collase to the statio...

  2. Contamination Control for Thermal Engineers

    Science.gov (United States)

    Rivera, Rachel B.

    2015-01-01

    The presentation will be given at the 26th Annual Thermal Fluids Analysis Workshop (TFAWS 2015) hosted by the Goddard Spaceflight Center (GSFC) Thermal Engineering Branch (Code 545). This course will cover the basics of Contamination Control, including contamination control related failures, the effects of contamination on Flight Hardware, what contamination requirements translate to, design methodology, and implementing contamination control into Integration, Testing and Launch.

  3. Lead-210 contamination

    Energy Technology Data Exchange (ETDEWEB)

    Gray, P. [Peter Gray and Associates, Tulsa, OK (United States)

    1997-12-31

    Nearly all scrap dealers, smelters and other recyclers routinely monitor for radioactivity in shipments entering their facility. These sensitive radiation gate monitors easily detect radium-226 and most other radioactive nuclides. However, the type of detector normally used, sodium iodide scintillation crystals, will not detect the low energy gamma radiation emitted by lead-210 and its progeny. Since lead-210 is a common radioactive contaminant in certain industries, contaminated scrap metal from these industries may avoid detection at the recycler. Lead-210 is a decay product of radon-222 which is produced in small concentrations with natural gas. As the natural gas liquids, particularly ethane and propane, are separated from the natural gas, the radon concentrates in the ethane/propane fraction. The natural gas industry, particularly gas processing facilities and industries using ethane and propane as feed stocks can be significantly contaminated with the radon decay products, especially lead-210, bismuth-210 and polonium-210. Unless the scrap metal is decontaminated before sending to the recycler, the lead-210 contaminated scrap may be processed, resulting in some degree of radioactive contamination of the recycling facilities. Methods of detecting the low energy gamma radiation associated with lead-210 include the pancake G-M detector and the thin crystal-thin window scintillation detector.

  4. Adaptive filtering prediction and control

    CERN Document Server

    Goodwin, Graham C

    2009-01-01

    Preface1. Introduction to Adaptive TechniquesPart 1. Deterministic Systems2. Models for Deterministic Dynamical Systems3. Parameter Estimation for Deterministic Systems4. Deterministic Adaptive Prediction5. Control of Linear Deterministic Systems6. Adaptive Control of Linear Deterministic SystemsPart 2. Stochastic Systems7. Optimal Filtering and Prediction8. Parameter Estimation for Stochastic Dynamic Systems9. Adaptive Filtering and Prediction10. Control of Stochastic Systems11. Adaptive Control of Stochastic SystemsAppendicesA. A Brief Review of Some Results from Systems TheoryB. A Summary o

  5. Tunable-Bandwidth Filter System

    Science.gov (United States)

    Aye, Tin; Yu, Kevin; Dimov, Fedor; Savant, Gajendra

    2006-01-01

    A tunable-bandwidth filter system (TBFS), now undergoing development, is intended to be part of a remote-sensing multispectral imaging system that will operate in the visible and near infrared spectral region (wavelengths from 400 to 900 nm). Attributes of the TBFS include rapid tunability of the pass band over a wide wavelength range and high transmission efficiency. The TBFS is based on a unique integration of two pairs of broadband Raman reflection holographic filters with two rotating spherical lenses. In experiments, a prototype of the TBFS was shown to be capable of spectral sampling of images in the visible range over a 200-nm spectral range with a spectral resolution of .30 nm. The figure depicts the optical layout of a prototype of the TBFS as part of a laboratory multispectral imaging system for the spectral sampling of color test images in two orthogonal polarizations. Each pair of broadband Raman reflection holographic filters is mounted at an equatorial plane between two halves of a spherical lens. The two filters in each pair are characterized by steep spectral slopes (equivalently, narrow spectral edges), no ripple or side lobes in their pass bands, and a few nanometers of non-overlapping wavelength range between their pass bands. Each spherical lens and thus the filter pair within it is rotated in order to rapidly tune its pass band. The rotations of the lenses are effected by electronically controlled, programmable, high-precision rotation stages. The rotations are coordinated by electronic circuits operating under overall supervision of a personal computer in order to obtain the desired variation of the overall pass bands with time. Embedding the filters inside the spherical lenses increases the range of the hologram incidence angles, making it possible to continuously tune the pass and stop bands of the filters over a wider wavelength range. In addition, each spherical lens also serves as part of the imaging optics: The telephoto lens focuses

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

    Directory of Open Access Journals (Sweden)

    Leila kabbai

    2016-07-01

    Full Text Available 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 operations will be presented. The first way is done using the standard method. The second way uses Field Programmable Gate Array (FPGA features Digital Signal Processor (DSP to ensure and make fast the scalability of the effective FPGA resource and then to speed up calculation. The third way uses real multiplier for more precision and a the maximum uses of FPGA resources. In this paper, we compare the image quality of hardware (VHDL and software (MATLAB implementation using the Peak Signal-to-Noise Ratio (PSNR. Also, the FPGA resource usage for different sizes of Gaussian kernel will be presented in order to provide a comparison between fixed-point and floating point implementations.

  7. The Effect of KangLaite and 5-Fluorouracil on proliferation and apoptosis of Hepa1-6 cell%康莱特联合5-Fu对肝癌细胞Heap1-6的作用

    Institute of Scientific and Technical Information of China (English)

    刘燕燕; 赵和平

    2010-01-01

    目的 研究康莱特(KLT)联用半量最佳体外抑瘤浓度5-氟尿嘧啶(5-Fu)、单药全量5-Fu对体外小鼠Heap1-6肝癌细胞增殖及凋亡的影响.方法 采用MTT法检测各药物组对细胞活性的影响;采用流式细胞术分析各药物组对肝癌细胞株Hepa1-6细胞周期的影响.,结果 MTT示:康莱特联用半量5-Fu较单药全量5-Fu的抗肿瘤效果显著;高剂量康莱特联合半量5-Fu的抗肝癌效果较低、中剂量组联合组显著.流式细胞术示:不同浓度的康莱特联合半量5-Fu较全量5-Fu的促凋亡作用差异在中剂量时差异无显著性.结论 中剂量的康莱特联用半量5-Fu对肿瘤细胞的抑制作用及促凋亡作用与单药5-Fu的疗效相当,可以指导临床用药.

  8. Soy isoflavones increase quinone reductase in hepa-1c1c7 cells via estrogen receptor beta and nuclear factor erythroid 2-related factor 2 binding to the antioxidant response element.

    Science.gov (United States)

    Froyen, Erik B; Steinberg, Francene M

    2011-09-01

    Soy protein and isoflavones (genistein and daidzein) have been demonstrated to increase quinone reductase (QR) activity, protein, and mRNA in animal and cell culture models. However, their mechanism of action has not been completely characterized. Additionally, it has not been determined if equol, a daidzein metabolite, can modulate QR activity and expression. Estrogen receptor beta (ERβ) is thought to be involved in stimulating QR gene transcription by anti-estrogens and phytoestrogens, along with nuclear factor erythroid 2-related factor 2 (Nrf2). This study tested the hypothesis that genistein, daidzein and equol increase quinone reductase activity, protein and mRNA via ERβ and Nrf2 binding to the QR antioxidant response element (ARE). QR expression and activity were determined using TaqMan polymerase chain reaction, protein immunoblots and activity assays. Molecular events were investigated using luciferase reporter gene assays and chromatin immunoprecipitation (ChIP). Hepa-1c1c7 cells were treated with control [0.1% (v:v) dimethyl sulfoxide (DMSO)]; 1 μmol/L β-naphthoflavone (positive control); 5 μmol/L resveratrol (ChIP positive control for ERβ binding) and 1, 5 and 25 μmol/L genistein, daidzein or equol. Treatment durations were 1 h (ChIP), 24 h (mRNA and luciferase assays) and 24 and 48 h (protein and activity). Genistein, daidzein and equol increased QR activity, protein and mRNA, with daidzein and equol having more of an impact at physiologic concentrations (1 and 5 μmol/L) compared to genistein. Furthermore, the study results demonstrate that genistein, daidzein and equol interact with the QR ARE and that daidzein and equol act via both ERβ and Nrf2 binding strongly to the QR ARE.

  9. Camel Milk Modulates the Expression of Aryl Hydrocarbon Receptor-Regulated Genes, Cyp1a1, Nqo1, and Gsta1, in Murine hepatoma Hepa 1c1c7 Cells

    Directory of Open Access Journals (Sweden)

    Hesham M. Korashy

    2012-01-01

    Full Text Available There is a traditional belief in the Middle East that camel milk may aid in prevention and treatment of numerous cases of cancer yet, the exact mechanism was not investigated. Therefore, we examined the ability of camel milk to modulate the expression of a well-known cancer-activating gene, Cytochrome P450 1a1 (Cyp1a1, and cancer-protective genes, NAD(PH:quinone oxidoreductase 1 (Nqo1 and glutathione S-transferase a1 (Gsta1, in murine hepatoma Hepa 1c1c7 cell line. Our results showed that camel milk significantly inhibited the induction of Cyp1a1 gene expression by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, the most potent Cyp1a1 inducer and known carcinogenic chemical, at mRNA, protein, and activity levels in a concentration-dependent manner. In addition, camel milk significantly decreased the xenobiotic responsive element (XRE-dependent luciferase activity, suggesting a transcriptional mechanism is involved. Furthermore, this inhibitory effect of camel milk was associated with a proportional increase in heme oxygenase 1. On the other hand, camel milk significantly induced Nqo1 and Gsta1 mRNA expression level in a concentration-dependent fashion. The RNA synthesis inhibitor, actinomycin D, completely blocked the induction of Nqo1 mRNA by camel milk suggesting the requirement of de novo RNA synthesis through a transcriptional mechanism. In conclusion, camel milk modulates the expression of Cyp1a1, Nqo1, and Gsta1 at the transcriptional and posttranscriptional levels.

  10. Design and fabrication of multiple airgap-based visible filters

    Science.gov (United States)

    Ghaderi, M.; Wolffenbuttel, R. F.

    2014-05-01

    The efficiency of a Bragg reflector design for implementation in optical resonators is highly dependent on the ratio between the high-index material and the low-index material used for the quarter-wavelength (QWOT) layers. A higher contrast implies that fewer layers are required to achieve a specified spectral selectivity over a wider spectral band. In turn, the reduced total thickness of the filter stack reduces the effect of optical absorption in the layers. The research presented here focuses on implementation of filters on top of silicon detectors that are already fabricated in a CMOS process. This implies that the constraints of process compatibility, such as the materials to be used, process temperature and cleanroom reentrance related to contamination, need to be considered. Silicon-dioxide is often used in CMOS-compatible designs, which has an index of refraction n~1.5, thus limiting nHi/nLo to about 2. This value can be improved by 50% when using air-films as the low-n material. Surface micromachining is used for the fabrication of such mirrors. Multiple layers of Si and SiO2 were alternatingly deposited, and subsequently the Si layers are selectively removed in a sacrificial etch. The width of the λ/4 air-gaps is about 100 nm, which is narrower as compared to the typical layer thickness that is used in surface micromachining for conventional MEMS applications. Moreover, a demanding optical design requires more layers than typically used in a conventional MEMS device. Since the number of stacked layers is significantly higher as compared to the conventional MEMS, fabricating such filters is a challenge. However, unlike a conventional MEMS, electrical contacting to the structural layers is not required in optical filter application, which, eases the fabrication of such filters. This paper presents the design of several 4-layer structures for use in the visible spectral range, along with the fabrication sequence and preliminary measurement results.

  11. Mecoprop (MCPP) removal in full-scale rapid sand filters at a groundwater-based waterworks

    Energy Technology Data Exchange (ETDEWEB)

    Hedegaard, Mathilde J., E-mail: mjhe@env.dtu.dk; Arvin, Erik; Corfitzen, Charlotte B.; Albrechtsen, Hans-Jørgen

    2014-11-15

    Contamination by the herbicide mecoprop (MCPP) was detected in groundwater abstraction wells at Kerteminde Waterworks in concentrations up to 0.08 μg/L. MCPP was removed to below detection limit in a simple treatment line where anaerobic groundwater was aerated and subsequently filtered by primary and secondary rapid sand filters. Water quality parameters were measured throughout the waterworks, and they behaved as designed for. MCPP was removed in secondary rapid sand filters — removal was the greatest in the sand filters in the filter line with the highest contact time (63 min). In these secondary sand filters, MCPP concentration decreased from 0.037 μg/L to below the detection limit of 0.01 μg/L. MCPP was removed continuously at different filter depths (0.80 m). Additionally, biodegradation, mineralisation and adsorption were investigated in the laboratory in order to elucidate removal mechanisms in the full-scale system. Therefore, microcosms were set up with filter sand, water and {sup 14}C-labelled MCPP at an initial concentration of 0.2 μg/L. After 24 h, 79–86% of the initial concentration of MCPP was removed. Sorption removed 11–15%, while the remaining part was removed by microbial processes, leading to a complete mineralisation of 13–18%. Microbial removal in the filter sand was similar at different depths of the rapid sand filter, while the amount of MCPP which adsorbed to the filter sand after 48 h decreased with depth from 21% of the initial MCPP in the top layer to 7% in the bottom layer. It was concluded that MCPP was removed in secondary rapid sand filters at Kerteminde Waterworks, to which both adsorption and microbial degradation contributed. - Highlights: • A full-scale groundwater based waterworks was able to remove MCPP. • In the secondary rapid sand filters, MCPP decreased from 0.037 μg/L to < 0.010 μg/L. • The filter sand removed MCPP both by sorption and by microbial degradation. • Microbial removal was unchanged while

  12. Environmental Contaminants in Foodstuffs

    Directory of Open Access Journals (Sweden)

    Mária Túri-Szerletics

    2008-06-01

    Full Text Available Consumers have specific concerns about food contaminants but often lack themeans to make appropriate judgements on what is high risk and what is not. Contaminantsin foods can be grouped according to their origin and nature. Environmental contaminantsof food-safety concern includes toxic metals and elements, organometallic compounds,agricultural chemicals and persistent organic pollutants such as halogenated hydrocarbonpesticides, polychlorinated biphenyls, dioxins, polycyclic aromatic hydrocarbons,phthalates, nirates, nitrites. These contaminants may present a potential hazard for humanhealth if exposure exceeds tolerable levels. This article shows the characteristics and thedietary intake of these elements and compounds. Further works need to concentrate onmechanism of different contaminants toxicity and metabolism, reevaluation of acceptablelimits, and their control in foods and in the environment.

  13. Laboratory evaluation of geosynthetic fabric containers for contaminant migration

    Energy Technology Data Exchange (ETDEWEB)

    Moo-Young, H.; Ochola, C.

    1999-07-01

    There exist various methods to determine the filtration properties of geotextiles, and most of these methods are based on the Apparent Opening Size (AOS) or O{sub 95} value as designated by ASTM D-4751 ``Standard Test Method for Determining Apparent Opening Size of a Geotextile''. The ability of a geotextile to function as an effective filter is dependent on the granularity of the medium being filtered, hydraulic conditions, and the configuration of the pore spaces within the geotextile. Current methods to determine the AOS do not take into consideration the various strains that the geotextiles may experience in the field, and are therefore based on static conditions or under no strain which may not be representative of what happens to a geotextile when in use. The utilization of GFC's to reduce the movement of contaminated sediments have necessitated the investigation of the migration of fines through various geotextile configurations used to construct the GFCs, and to determine the amount of total suspended solids that would be released. This laboratory study investigates the migration of fines and contaminants through GFCs. Contaminated dredges sediment was characterized for the physical and chemical properties. Hanging bag tests, barge simulation tests, fabric analysis strain tests, and pressure filtration tests with varying strain were conducted on the contaminated sediment and GFC configurations to determine the amount of total suspended solids that would be released to the water column.

  14. Particle Kalman Filtering: A Nonlinear Bayesian Framework for Ensemble Kalman Filters

    CERN Document Server

    Hoteit, Ibrahim; Pham, Dinh-Tuan

    2011-01-01

    This paper investigates an approximation scheme of the optimal nonlinear Bayesian filter based on the Gaussian mixture representation of the state probability distribution function. The resulting filter is similar to the particle filter, but is different from it in that, the standard weight-type correction in the particle filter is complemented by the Kalman-type correction with the associated covariance matrices in the Gaussian mixture. We show that this filter is an algorithm in between the Kalman filter and the particle filter, and therefore is referred to as the particle Kalman filter (PKF). In the PKF, the solution of a nonlinear filtering problem is expressed as the weighted average of an "ensemble of Kalman filters" operating in parallel. Running an ensemble of Kalman filters is, however, computationally prohibitive for realistic atmospheric and oceanic data assimilation problems. For this reason, we consider the construction of the PKF through an "ensemble" of ensemble Kalman filters (EnKFs) instead, ...

  15. Kalman Filtering with Real-Time Applications

    CERN Document Server

    Chui, Charles K

    2009-01-01

    Kalman Filtering with Real-Time Applications presents a thorough discussion of the mathematical theory and computational schemes of Kalman filtering. The filtering algorithms are derived via different approaches, including a direct method consisting of a series of elementary steps, and an indirect method based on innovation projection. Other topics include Kalman filtering for systems with correlated noise or colored noise, limiting Kalman filtering for time-invariant systems, extended Kalman filtering for nonlinear systems, interval Kalman filtering for uncertain systems, and wavelet Kalman filtering for multiresolution analysis of random signals. Most filtering algorithms are illustrated by using simplified radar tracking examples. The style of the book is informal, and the mathematics is elementary but rigorous. The text is self-contained, suitable for self-study, and accessible to all readers with a minimum knowledge of linear algebra, probability theory, and system engineering.

  16. Contamination Analysis Tools

    Science.gov (United States)

    Brieda, Lubos

    2015-01-01

    This talk presents 3 different tools developed recently for contamination analysis:HTML QCM analyzer: runs in a web browser, and allows for data analysis of QCM log filesJava RGA extractor: can load in multiple SRS.ana files and extract pressure vs. time dataC++ Contamination Simulation code: 3D particle tracing code for modeling transport of dust particulates and molecules. Uses residence time to determine if molecules stick. Particulates can be sampled from IEST-STD-1246 and be accelerated by aerodynamic forces.

  17. Groundwater contamination in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Tase, Norio [Univ. of Tsukuba, Ibaraki (Japan)

    1992-07-01

    Problems on groundwater contamination in Japan are briefly summarized in this paper. Although normal physical conditions in Japan restrict the possibilities of groundwater contamination, human activities are threatening groundwater resources. A survey by the Environment Agency of Japan showed nationwide spreading of organic substances, such as trichloroethylene as well as nitrogen compounds. Synthetic detergents have also been detected even in rural areas and in deep confined aquifers, although their concentrations are not as high. Public awareness of agrichemical or pesticides abuse, especially from golf courses, is apparent. Other problems such as nitrate-nitrogen, leachate from landfills, and the leaking of underground storage tanks are also discussed. 9 refs., 3 figs., 4 tabs.

  18. Groundwater contamination in Japan

    Science.gov (United States)

    Tase, Norio

    1992-07-01

    Problems on groundwater contamination in Japan are briefly summarized in this paper. Although normal physical conditions in Japan restrict the possibilities of groundwater contamination, human activities are threatening groundwater resources. A survey by the Environment Agency of Japan showed nationwide spreading of organic substances, such as trichloroethylene as well as nitrogen compounds. Synthetic detergents have also been detected even in rural areas and in deep confined aquifers, although their concentrations are not as high. Public awareness of agrichemical or pesticides abuse, especially from golf courses, is apparent. Other problems such as nitrate-nitrogen, leachate from landfills, and the leaking of underground storage tanks are also discussed.

  19. Rapid detection of Salmonella spp. in food by use of the ISO-GRID hydrophobic grid membrane filter.

    OpenAIRE

    Entis, P; Brodsky, M H; Sharpe, A N; Jarvis, G A

    1982-01-01

    A rapid hydrophobic grid-membrane filter (HGMF) method was developed and compared with the Health Protection Branch cultural method for the detection of Salmonella spp. in 798 spiked samples and 265 naturally contaminated samples of food. With the HGMF method, Salmonella spp. were isolated from 618 of the spiked samples and 190 of the naturally contaminated samples. The conventional method recovered Salmonella spp. from 622 spiked samples and 204 unspiked samples. The isolation rates from Sal...

  20. Bacteria/virus filter membrane

    Science.gov (United States)

    Lysaght, M. S.; Goodwin, F.; Roebelen, G.

    1977-01-01

    Hollow acrylate fiber membrane that filters bacterial and viral organisms can be used with closed-cycle life-support systems for underwater habitations or laboratories. Membrane also has applications in fields of medicine, gnotobiotics, pharmaceutical production, and industries and research facilities that require sterile water. Device eliminates need for strong chemicals or sterilizing agents, thereby reducing costs.

  1. 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.

  2. Sample-whitened matched filters

    DEFF Research Database (Denmark)

    Andersen, Ib

    1973-01-01

    components. These filters are shown to exist for ali realistic channels and the complete set of SWMF's for any channel is determined. It is shown that for nonpathological channels there is a unique SWMF which minimizes the amount of intersymbol interference defined as the discrete-time analog to the rms...

  3. Static Filtered Sky Color Constancy

    Directory of Open Access Journals (Sweden)

    Ali Alkhalifah

    2016-05-01

    Full Text Available In Computer Vision, the sky color is used for lighting correction, image color enhancement, horizon alignment, image indexing, and outdoor image classification and in many other applications. In this article, for robust color based sky segmentation and detection, usage of lighting correction for sky color detection is investigated. As such, the impact of color constancy on sky color detection algorithms is evaluated and investigated. The color correction (constancy algorithms used includes Gray-Edge (GE, Gray-World (GW, Max-RGB (MRGB and Shades-of-Gray (SG. The algorithms GE, GW, MRGB, and SG, are tested on the static filtered sky modeling. The static filter is developed in the LAB color space. This evaluation and analysis is essential for detection scenarios, especially, color based object detection in outdoor scenes. From the results, it is concluded that the color constancy before sky color detection using LAB static filters has the potential of improving sky color detection performance. However, the application of the color constancy can impart adverse effects on the detection results. For images, the color constancy algorithms depict a compact and stable representative of the sky chroma loci, however, the sky color locus might have a shifting and deviation in a particular color representation. Since the sky static filters are using the static chromatic values, different results can be obtained by applying color constancy algorithms on various datasets.

  4. Fast cartoon + texture image filters.

    Science.gov (United States)

    Buades, Antoni; Le, Triet M; Morel, Jean-Michel; Vese, Luminita A

    2010-08-01

    Can images be decomposed into the sum of a geometric part and a textural part? In a theoretical breakthrough, [Y. Meyer, Oscillating Patterns in Image Processing and Nonlinear Evolution Equations. Providence, RI: American Mathematical Society, 2001] proposed variational models that force the geometric part into the space of functions with bounded variation, and the textural part into a space of oscillatory distributions. Meyer's models are simple minimization problems extending the famous total variation model. However, their numerical solution has proved challenging. It is the object of a literature rich in variants and numerical attempts. This paper starts with the linear model, which reduces to a low-pass/high-pass filter pair. A simple conversion of the linear filter pair into a nonlinear filter pair involving the total variation is introduced. This new-proposed nonlinear filter pair retains both the essential features of Meyer's models and the simplicity and rapidity of the linear model. It depends upon only one transparent parameter: the texture scale, measured in pixel mesh. Comparative experiments show a better and faster separation of cartoon from texture. One application is illustrated: edge detection.

  5. Conflict-Induced Perceptual Filtering

    Science.gov (United States)

    Wendt, Mike; Luna-Rodriguez, Aquiles; Jacobsen, Thomas

    2012-01-01

    In a variety of conflict paradigms, target and distractor stimuli are defined in terms of perceptual features. Interference evoked by distractor stimuli tends to be reduced when the ratio of congruent to incongruent trials is decreased, suggesting conflict-induced perceptual filtering (i.e., adjusting the processing weights assigned to stimuli…

  6. Bacteria/virus filter membrane

    Science.gov (United States)

    Lysaght, M. S.; Goodwin, F.; Roebelen, G.

    1977-01-01

    Hollow acrylate fiber membrane that filters bacterial and viral organisms can be used with closed-cycle life-support systems for underwater habitations or laboratories. Membrane also has applications in fields of medicine, gnotobiotics, pharmaceutical production, and industries and research facilities that require sterile water. Device eliminates need for strong chemicals or sterilizing agents, thereby reducing costs.

  7. Service discovery using Bloom filters

    NARCIS (Netherlands)

    Goering, P.T.H.; Heijenk, Gerhard J.; Lelieveldt, B.P.F.; Haverkort, Boudewijn R.H.M.; de Laat, C.T.A.M.; Heijnsdijk, J.W.J.

    A protocol to perform service discovery in adhoc networks is introduced in this paper. Attenuated Bloom filters are used to distribute services to nodes in the neighborhood and thus enable local service discovery. The protocol has been implemented in a discrete event simulator to investigate the

  8. Quantized, piecewise linear filter network

    DEFF Research Database (Denmark)

    Sørensen, John Aasted

    1993-01-01

    A quantization based piecewise linear filter network is defined. A method for the training of this network based on local approximation in the input space is devised. The training is carried out by repeatedly alternating between vector quantization of the training set into quantization classes an...

  9. Design and Implementation of Wave Digital Filters

    Directory of Open Access Journals (Sweden)

    V. Davidek

    2001-09-01

    Full Text Available One of possibilities of the Wave Digital Filters (WDF design isusing the classical LC-filters theory. The aim of this paper is todemonstrate the design of WDF from the LC filter and the implementationof WDF on the fixed-point digital signal processor. The theory of wavedigital filter has been developed by using the classical scatteringparameter theory. The theory of ladder filters is well-known, and soour present problem can thus be reduced to a problem how to replace theL and C elements of the filters by adaptors and delay elements, addersand multipliers.

  10. Discrete continuous-phase superresolving filters.

    Science.gov (United States)

    Zhou, Sumei; Zhou, Changhe

    2004-12-01

    A new type of phase-only superresolving pupil filter with a discrete continuous-phase profile is presented that is a combination of discrete multilevel-phase modulation and continuous-phase modulation. This type of filter can achieve better superresolution performance than the continuous-phase filters reported in Opt. Lett. 28, 607 (2003). Therefore, with regard to the superresolution effect, this type of filter deserves study for practical applications. More importantly, the diffraction performance of this type of filter can explain the effect of a discrete-phase filter illuminated with a continuous wave front, whose superresolving performance cannot be analyzed with previous superresolution methods.

  11. Automated Integrated Analog Filter Design Issues

    Directory of Open Access Journals (Sweden)

    Karolis Kiela

    2015-07-01

    Full Text Available An analysis of modern automated integrated analog circuits design methods and their use in integrated filter design is done. Current modern analog circuits automated tools are based on optimization algorithms and/or new circuit generation methods. Most automated integrated filter design methods are only suited to gmC and switched current filter topologies. Here, an algorithm for an active RC integrated filter design is proposed, that can be used in automated filter designs. The algorithm is tested by designing an integrated active RC filter in a 65 nm CMOS technology.

  12. Performance comparison of various time variant filters

    Energy Technology Data Exchange (ETDEWEB)

    Kuwata, M. [JEOL Engineering Co. Ltd., Akishima, Tokyo (Japan); Husimi, K.

    1996-07-01

    This paper describes the advantage of the trapezoidal filter used in semiconductor detector system comparing with the other time variant filters. The trapezoidal filter is the compose of a rectangular pre-filter and a gated integrator. We indicate that the best performance is obtained by the differential-integral summing type rectangular pre-filter. This filter is not only superior in performance, but also has the useful feature that the rising edge of the output waveform is linear. We introduce an example of this feature used in a high-energy experiment. (author)

  13. Indirect Kalman Filter in Mobile Robot Application

    Directory of Open Access Journals (Sweden)

    Surachai Panich

    2010-01-01

    Full Text Available Problem statement: The most successful applications of Kalman filtering are to linearize about some nominal trajectory in state space that does not depend on the measurement data. The resulting filter is usually referred to as simply a linearized Kalman filter. Approach: This study introduced mainly indirect Kalman filter to estimate robot’s position. A developed differential encoder system integrated accelerometer is experimental tested in square shape. Results: Experimental results confirmed that indirect Kalman filter improves the accuracy and confidence of position estimation. Conclusion: In summary, we concluded that indirect Kalman filter has good potential to reduce error of measurement data.

  14. PSpice for filters and transmission lines

    CERN Document Server

    Tobin, Paul

    2007-01-01

    In this book, PSpice for Filters and Transmission Lines, we examine a range of active and passive filters where each design is simulated using the latest Cadence Orcad V10.5 PSpice capture software. These filters cannot match the very high order digital signal processing (DSP) filters considered in PSpice for Digital Signal Processing, but nevertheless these filters have many uses. The active filters considered were designed using Butterworth and Chebychev approximation loss functions rather than using the 'cookbook approach' so that the final design will meet a given specification in an exact

  15. Particle Filter for Estimation and Tracking

    Institute of Scientific and Technical Information of China (English)

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

    2010-01-01

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

  16. Pure E and B polarization maps via Wiener filtering

    CERN Document Server

    Bunn, Emory F

    2016-01-01

    In order to draw scientific conclusions from observations of cosmic microwave background (CMB) polarization, it is necessary to separate the contributions of the E and B components of the data. For data with incomplete sky coverage, there are ambiguous modes, which can be sourced by either E or B signals. Techniques exist for producing "pure" E and B maps, which are guaranteed to be free of cross-contamination, although the standard method, which involves constructing an eigenbasis, has a high computational cost. We show that such pure maps can be thought of as resulting from the application of a Wiener filter to the data. This perspective leads to far more efficient methods of producing pure maps. Moreover, by expressing the idea of purification in the general framework of Wiener filtering (i.e., maximization of a posterior probability), it leads to a variety of generalizations of the notion of pure E and B maps, e.g., accounting for noise or other contaminants in the data as well as correlations with temper...

  17. Pure E and B polarization maps via Wiener filtering

    Science.gov (United States)

    Bunn, Emory F.; Wandelt, Benjamin

    2017-08-01

    In order to draw scientific conclusions from observations of cosmic microwave background (CMB) polarization, it is necessary to separate the contributions of the E and B components of the data. For data with incomplete sky coverage, there are ambiguous modes, which can be sourced by either E or B signals. Techniques exist for producing "pure" E and B maps, which are guaranteed to be free of cross-contamination, although the standard method, which involves constructing an eigenbasis, has a high computational cost. We show that such pure maps can be thought of as resulting from the application of a Wiener filter to the data. This perspective leads to far more efficient methods of producing pure maps. Moreover, by expressing the idea of purification in the general framework of Wiener filtering (i.e., maximization of a posterior probability), it leads to a variety of generalizations of the notion of pure E and B maps, e.g., accounting for noise or other contaminants in the data as well as correlations with temperature anisotropy.

  18. Graphene oxide as filter media to remove levofloxacin and lead from aqueous solution.

    Science.gov (United States)

    Dong, Shunan; Sun, Yuanyuan; Wu, Jichun; Wu, Benjun; Creamer, Anne Elise; Gao, Bin

    2016-05-01

    There is an increasing need to develop novel and high-efficiency water purification technologies. This work systematically evaluated the potential of using graphene oxide (GO) directly as filter media for the removal of levofloxacin (LEV), an emerging contaminate, and lead (Pb), a heavy metal, from aqueous solution. Batch and fixed-bed experiments were conducted to determine the sorption behaviors of LEV and Pb onto the GO. In the batch system, GO showed strong sorption of the two contaminants with Langmuir maximum adsorption capacities of 256.6 and 227.2 mg g(-1), respectively. The removal of LEV and Pb by GO in fixed-bed columns was high under all tested conditions in both single and mixed solution systems. The removal efficiency of the two contaminants in the GO-sand columns increased with increasing GO content, but decreased with increasing injection flow rate. In the mixed solution system, although LEV and Pb competed for sorption, the GO media still had high removal efficiencies for them. The column experimental data were well described by the Bed Depth Service Time (BDST) model, suggesting the model can be used for the design of GO-sand filters in large-scale applications. Findings from this work demonstrated that GO is a promising nano-adsorbent that can be used as a high-efficiency filter media in water treatment to remove hazardous metal elements and emerging contaminants.

  19. 燃气轮机高效空气过滤器在极端天气下的应用对策%Countermeasures of Gas Turbine High Efficiency Air Filters in Extreme Weather Conditions

    Institute of Scientific and Technical Information of China (English)

    李俊; 龙涛

    2015-01-01

    对燃气轮机的进气过滤系统进行了升级改造,将进气过滤系统的过滤等级由F8级提升到了H11级。改造后过滤效率明显提升,压气机长期不需要进行水洗,保持在高效率状态下运行,发电机组的平均发电效率也得以提升,经济效益非常可观。升级后的进气过滤系统在现场运行过程中遇到了多种恶劣天气工况,如沙尘、暴雨大雾天气和空气中含油性物质等。通过对过滤器的滤材及结构进行改进,最终开发和筛选出对各种恶劣大气条件适应性强的高效过滤器。同时在日常运行中,我们也积累了一些处理突发状况的经验和总结了一些合理使用高效过滤器的策略。%The level of filtration of the inlet air filtration system for gas turbine was upgraded from F8 to H11.The filtration efficiency of air intake system improved significantly after the improvement was completed.The compressor need not washing for long term, and can keep working in a high state of efficiency.The average power generation efficiency of the unit can be improved which can bring consid-erable economic benefit.The upgraded air inlet filter system run in variety of weather conditions , such as sand dust weather, rainstorm weather, foggy weather and the condition that the air always contains oil substance.We found the type of High Efficiency Particulate Air ( HEPA) filter which can be well adapted to a variety of bad weather by improving the material and structure of filers.At the same time,some deal with emergency situation experiences accumulated during daily operation and some reasonable use strategy of HEPA fil-ter is summarized.

  20. Adaptive linear predictor FIR filter based on the Cyclone V FPGA with HPS to reduce narrow band RFI in AERA radio detection of cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Szadkowski, Zbigniew [University of Lodz, Department of Physics and Applied Informatics, 90-236 Lodz, (Poland)

    2015-07-01

    We present the new approach to a filtering of radio frequency interferences (RFI) in the Auger Engineering Radio Array (AERA) which study the electromagnetic part of the Extensive Air Showers. The radio stations can observe radio signals caused by coherent emissions due to geomagnetic radiation and charge excess processes. AERA observes frequency band from 30 to 80 MHz. This range is highly contaminated by human-made RFI. In order to improve the signal to noise ratio RFI filters are used in AERA to suppress this contamination. The first kind of filter used by AERA was the Median one, based on the Fast Fourier Transform (FFT) technique. The second one, which is currently in use, is the infinite impulse response (IIR) notch filter. The proposed new filter is a finite impulse response (FIR) filter based on a linear prediction (LP). A periodic contamination hidden in a registered signal (digitized in the ADC) can be extracted and next subtracted to make signal cleaner. The FIR filter requires a calculation of n=32, 64 or even 128 coefficients (dependent on a required speed or accuracy) by solving of n linear equations with coefficients built from the covariance Toeplitz matrix. This matrix can be solved by the Levinson recursion, which is much faster than the Gauss procedure. The filter has been already tested in the real AERA radio stations on Argentinean pampas with a very successful results. The linear equations were solved either in the virtual soft-core NIOSR processor (implemented in the FPGA chip as a net of logic elements) or in the external Voipac PXA270M ARM processor. The NIOS processor is relatively slow (50 MHz internal clock), calculations performed in an external processor consume a significant amount of time for data exchange between the FPGA and the processor. Test showed a very good efficiency of the RFI suppression for stationary (long-term) contaminations. However, we observed a short-time contaminations, which could not be suppressed either by the

  1. CONTAMINATED PROCESS EQUIPMENT REMOVAL FOR THE D&D OF THE 232-Z CONTAMINATED WASTE RECOVERY PROCESS FACILITY AT THE PLUTONIUM FINISHING PLANT (PFP)

    Energy Technology Data Exchange (ETDEWEB)

    HOPKINS, A.M.; MINETTE, M.J.; KLOS, D.B.

    2007-01-25

    This paper describes the unique challenges encountered and subsequent resolutions to accomplish the deactivation and decontamination of a plutonium ash contaminated building. The 232-Z Contaminated Waste Recovery Process Facility at the Plutonium Finishing Plant was used to recover plutonium from process wastes such as rags, gloves, containers and other items by incinerating the items and dissolving the resulting ash. The incineration process resulted in a light-weight plutonium ash residue that was highly mobile in air. This light-weight ash coated the incinerator's process equipment, which included gloveboxes, blowers, filters, furnaces, ducts, and filter boxes. Significant airborne contamination (over 1 million derived air concentration hours [DAC]) was found in the scrubber cell of the facility. Over 1300 grams of plutonium held up in the process equipment and attached to the walls had to be removed, packaged and disposed. This ash had to be removed before demolition of the building could take place.

  2. On Some Fuzzy Filters in Pseudo-BCI Algebras

    Directory of Open Access Journals (Sweden)

    Xiaohong Zhang

    2014-01-01

    Full Text Available Some new properties of fuzzy associative filters (also known as fuzzy associative pseudo-filters, fuzzy p-filter (also known as fuzzy pseudo-p-filters, and fuzzy a-filter (also known as fuzzy pseudo-a-filters in pseudo-BCI algebras are investigated. By these properties, the following important results are proved: (1 a fuzzy filter (also known as fuzzy pseudo-filters of a pseudo-BCI algebra is a fuzzy associative filter if and only if it is a fuzzy a-filter; (2 a filter (also known as pseudo-filter of a pseudo-BCI algebra is associative if and only if it is an a-filter (also call it pseudo-a filter; (3 a fuzzy filter of a pseudo-BCI algebra is fuzzy a-filter if and only if it is both a fuzzy p-filter and a fuzzy q-filter.

  3. Effect of filter media thickness on the performance of sand drying beds used for faecal sludge management.

    Science.gov (United States)

    Manga, M; Evans, B E; Camargo-Valero, M A; Horan, N J

    2016-12-01

    The effect of sand filter media thickness on the performance of faecal sludge (FS) drying beds was determined in terms of: dewatering time, contaminant load removal efficiency, solids generation rate, nutrient content and helminth eggs viability in the dried sludge. A mixture of ventilated improved pit latrine sludge and septage in the ratio 1:2 was dewatered using three pilot-scale sludge drying beds with sand media thicknesses of 150, 250 and 350 mm. Five dewatering cycles were conducted and monitored for each drying bed. Although the 150 mm filter had the shortest average dewatering time of 3.65 days followed by 250 mm and 350 mm filters with 3.83 and 4.02 days, respectively, there was no significant difference (p > 0.05) attributable to filter media thickness configurations. However, there was a significant difference for the percolate contaminant loads in the removal and recovery efficiency of suspended solids, total solids, total volatile solids, nitrogen species, total phosphorus, chemical oxygen demand, dissolved chemical oxygen demand and biochemical oxygen demand, with the highest removal efficiency for each parameter achieved by the 350 mm filter. There were also significant differences in the nutrient content (NPK) and helminth eggs viability of the solids generated by the tested filters. Filtering media configurations similar to 350 mm have the greatest potential for optimising nutrient recovery from FS.

  4. Mercury contamination extraction

    Science.gov (United States)

    Fuhrmann, Mark; Heiser, John; Kalb, Paul

    2009-09-15

    Mercury is removed from contaminated waste by firstly applying a sulfur reagent to the waste. Mercury in the waste is then permitted to migrate to the reagent and is stabilized in a mercury sulfide compound. The stable compound may then be removed from the waste which itself remains in situ following mercury removal therefrom.

  5. DSCOVR Contamination Lessons Learned

    Science.gov (United States)

    Graziani, Larissa

    2015-01-01

    The Triana observatory was built at NASA GSFC in the late 1990's, then placed into storage. After approximately ten years it was removed from storage and repurposed as the Deep Space Climate Observatory (DSCOVR). This presentation outlines the contamination control program lessons learned during the integration, test and launch of DSCOVR.

  6. FPGA design and implementation of Gaussian filter

    Science.gov (United States)

    Yang, Zhihui; Zhou, Gang

    2015-12-01

    In this paper , we choose four different variances of 1,3,6 and 12 to conduct FPGA design with three kinds of Gaussian filtering algorithm ,they are implementing Gaussian filter with a Gaussian filter template, Gaussian filter approximation with mean filtering and Gaussian filter approximation with IIR filtering. By waveform simulation and synthesis, we get the processing results on the experimental image and the consumption of FPGA resources of the three methods. We set the result of Gaussian filter used in matlab as standard to get the result error. By comparing the FPGA resources and the error of FPGA implementation methods, we get the best FPGA design to achieve a Gaussian filter. Conclusions can be drawn based on the results we have already got. When the variance is small, the FPGA resources is enough for the algorithm to implement Gaussian filter with a Gaussian filter template which is the best choice. But when the variance is so large that there is no more FPGA resources, we can chose the mean to approximate Gaussian filter with IIR filtering.

  7. Subsurface Contamination Control

    Energy Technology Data Exchange (ETDEWEB)

    Y. Yuan

    2001-11-16

    There are two objectives of this report, ''Subsurface Contamination Control''. The first is to provide a technical basis for recommending limiting radioactive contamination levels (LRCL) on the external surfaces of waste packages (WP) for acceptance into the subsurface repository. The second is to provide an evaluation of the magnitude of potential releases from a defective WP and the detectability of the released contents. The technical basis for deriving LRCL has been established in ''Retrieval Equipment and Strategy for Wp on Pallet'' (CRWMS M and O 2000g, 6.3.1). This report updates the derivation by incorporating the latest design information of the subsurface repository for site recommendation. The derived LRCL on the external surface of WPs, therefore, supercede that described in CRWMS M and O 2000g. The derived LRCL represent the average concentrations of contamination on the external surfaces of each WP that must not be exceeded before the WP is to be transported to the subsurface facility for emplacement. The evaluation of potential releases is necessary to control the potential contamination of the subsurface repository and to detect prematurely failed WPs. The detection of failed WPs is required in order to provide reasonable assurance that the integrity of each WP is intact prior to MGR closure. An emplaced WP may become breached due to manufacturing defects or improper weld combined with failure to detect the defect, by corrosion, or by mechanical penetration due to accidents or rockfall conditions. The breached WP may release its gaseous and volatile radionuclide content to the subsurface environment and result in contaminating the subsurface facility. The scope of this analysis is limited to radioactive contaminants resulting from breached WPs during the preclosure period of the subsurface repository. This report: (1) documents a method for deriving LRCL on the external surfaces of WP for acceptance into the

  8. Subsurface Contamination Control

    Energy Technology Data Exchange (ETDEWEB)

    Y. Yuan

    2001-12-12

    There are two objectives of this report, ''Subsurface Contamination Control''. The first is to provide a technical basis for recommending limiting radioactive contamination levels (LRCL) on the external surfaces of waste packages (WP) for acceptance into the subsurface repository. The second is to provide an evaluation of the magnitude of potential releases from a defective WP and the detectability of the released contents. The technical basis for deriving LRCL has been established in ''Retrieval Equipment and Strategy for Wp on Pallet'' (CRWMS M and O 2000g, 6.3.1). This report updates the derivation by incorporating the latest design information of the subsurface repository for site recommendation. The derived LRCL on the external surface of WPs, therefore, supercede that described in CRWMS M and O 2000g. The derived LRCL represent the average concentrations of contamination on the external surfaces of each WP that must not be exceeded before the WP is to be transported to the subsurface facility for emplacement. The evaluation of potential releases is necessary to control the potential contamination of the subsurface repository and to detect prematurely failed WPs. The detection of failed WPs is required in order to provide reasonable assurance that the integrity of each WP is intact prior to MGR closure. An emplaced WP may become breached due to manufacturing defects or improper weld combined with failure to detect the defect, by corrosion, or by mechanical penetration due to accidents or rockfall conditions. The breached WP may release its gaseous and volatile radionuclide content to the subsurface environment and result in contaminating the subsurface facility. The scope of this analysis is limited to radioactive contaminants resulting from breached WPs during the preclosure period of the subsurface repository. This report: (1) documents a method for deriving LRCL on the external surfaces of WP for acceptance into the

  9. A cost-effective weighing chamber for particulate matter filters.

    Science.gov (United States)

    Allen, R; Box, M; Liu, L J; Larson, T V

    2001-12-01

    Particulate matter (PM) is a ubiquitous air pollutant that has been receiving increasing attention in recent years due in part to the association between PM and a number of adverse health outcomes, including mortality and increases in emergency room visits and respiratory symptoms, as well as exacerbation of asthma and decrements in lung function. As a result, the ability to accurately sample ambient PM has become important, both to researchers and to regulatory agencies. The federal reference method for the determination of fine PM as PM2.5 in the atmosphere recommends that particle-sampling filters be conditioned and weighed in an environment with constant temperature and relative humidity (RH). It is also recommended that vibration, electrostatic charges, and contamination of the filters from laboratory air be minimized to reduce variability in filter weight measurements. These controls have typically been maintained in small, environmentally controlled "cleanrooms." As an alternative to constructing an elaborate cleanroom, we have designed, and presented in this paper, an inexpensive weighing chamber to maintain the necessary level of humidity control.

  10. Fuzzy Filtering Method for Color Videos Corrupted by Additive Noise

    Directory of Open Access Journals (Sweden)

    Volodymyr I. Ponomaryov

    2014-01-01

    Full Text Available A novel method for the denoising of color videos corrupted by additive noise is presented in this paper. The proposed technique consists of three principal filtering steps: spatial, spatiotemporal, and spatial postprocessing. In contrast to other state-of-the-art algorithms, during the first spatial step, the eight gradient values in different directions for pixels located in the vicinity of a central pixel as well as the R, G, and B channel correlation between the analogous pixels in different color bands are taken into account. These gradient values give the information about the level of contamination then the designed fuzzy rules are used to preserve the image features (textures, edges, sharpness, chromatic properties, etc.. In the second step, two neighboring video frames are processed together. Possible local motions between neighboring frames are estimated using block matching procedure in eight directions to perform interframe filtering. In the final step, the edges and smoothed regions in a current frame are distinguished for final postprocessing filtering. Numerous simulation results confirm that this novel 3D fuzzy method performs better than other state-of-the-art techniques in terms of objective criteria (PSNR, MAE, NCD, and SSIM as well as subjective perception via the human vision system in the different color videos.

  11. Rayleigh-maximum-likelihood bilateral filter for ultrasound image enhancement.

    Science.gov (United States)

    Li, Haiyan; Wu, Jun; Miao, Aimin; Yu, Pengfei; Chen, Jianhua; Zhang, Yufeng

    2017-04-17

    Ultrasound imaging plays an important role in computer diagnosis since it is non-invasive and cost-effective. However, ultrasound images are inevitably contaminated by noise and speckle during acquisition. Noise and speckle directly impact the physician to interpret the images and decrease the accuracy in clinical diagnosis. Denoising method is an important component to enhance the quality of ultrasound images; however, several limitations discourage the results because current denoising methods can remove noise while ignoring the statistical characteristics of speckle and thus undermining the effectiveness of despeckling, or vice versa. In addition, most existing algorithms do not identify noise, speckle or edge before removing noise or speckle, and thus they reduce noise and speckle while blurring edge details. Therefore, it is a challenging issue for the traditional methods to effectively remove noise and speckle in ultrasound images while preserving edge details. To overcome the above-mentioned limitations, a novel method, called Rayleigh-maximum-likelihood switching bilateral filter (RSBF) is proposed to enhance ultrasound images by two steps: noise, speckle and edge detection followed by filtering. Firstly, a sorted quadrant median vector scheme is utilized to calculate the reference median in a filtering window in comparison with the central pixel to classify the target pixel as noise, speckle or noise-free. Subsequently, the noise is removed by a bilateral filter and the speckle is suppressed by a Rayleigh-maximum-likelihood filter while the noise-free pixels are kept unchanged. To quantitatively evaluate the performance of the proposed method, synthetic ultrasound images contaminated by speckle are simulated by using the speckle model that is subjected to Rayleigh distribution. Thereafter, the corrupted synthetic images are generated by the original image multiplied with the Rayleigh distributed speckle of various signal to noise ratio (SNR) levels and

  12. Complex step-based low-rank extended Kalman filtering for state-parameter estimation in subsurface transport models

    KAUST Repository

    El Gharamti, Mohamad

    2014-02-01

    The accuracy of groundwater flow and transport model predictions highly depends on our knowledge of subsurface physical parameters. Assimilation of contaminant concentration data from shallow dug wells could help improving model behavior, eventually resulting in better forecasts. In this paper, we propose a joint state-parameter estimation scheme which efficiently integrates a low-rank extended Kalman filtering technique, namely the Singular Evolutive Extended Kalman (SEEK) filter, with the prominent complex-step method (CSM). The SEEK filter avoids the prohibitive computational burden of the Extended Kalman filter by updating the forecast along the directions of error growth only, called filter correction directions. CSM is used within the SEEK filter to efficiently compute model derivatives with respect to the state and parameters along the filter correction directions. CSM is derived using complex Taylor expansion and is second order accurate. It is proven to guarantee accurate gradient computations with zero numerical round-off errors, but requires complexifying the numerical code. We perform twin-experiments to test the performance of the CSM-based SEEK for estimating the state and parameters of a subsurface contaminant transport model. We compare the efficiency and the accuracy of the proposed scheme with two standard finite difference-based SEEK filters as well as with the ensemble Kalman filter (EnKF). Assimilation results suggest that the use of the CSM in the context of the SEEK filter may provide up to 80% more accurate solutions when compared to standard finite difference schemes and is competitive with the EnKF, even providing more accurate results in certain situations. We analyze the results based on two different observation strategies. We also discuss the complexification of the numerical code and show that this could be efficiently implemented in the context of subsurface flow models. © 2013 Elsevier B.V.

  13. Deep Ultraviolet Macroporous Silicon Filters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I proposal describes a novel method to make deep and far UV optical filters from macroporous silicon. This type of filter consists of an array of...

  14. WAVELET RATIONAL FILTERS AND REGULARITY ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    Zheng Kuang; Ming-gen Cui

    2000-01-01

    In this paper, we choose the trigonometric rational functions as wavelet filters and use them to derive various wavelets. Especially for a certain family of wavelets generated by the rational filters, the better smoothness results than Daubechies' are obtained.

  15. Adaptive Marginal Median Filter for Colour Images

    Directory of Open Access Journals (Sweden)

    Almanzor Sapena

    2011-03-01

    Full Text Available This paper describes a new filter for impulse noise reduction in colour images which is aimed at improving the noise reduction capability of the classical vector median filter. The filter is inspired by the application of a vector marginal median filtering process over a selected group of pixels in each filtering window. This selection, which is based on the vector median, along with the application of the marginal median operation constitutes an adaptive process that leads to a more robust filter design. Also, the proposed method is able to process colour images without introducing colour artifacts. Experimental results show that the images filtered with the proposed method contain less noisy pixels than those obtained through the vector median filter.

  16. Signal interference RF photonic bandstop filter.

    Science.gov (United States)

    Aryanfar, Iman; Choudhary, Amol; Shahnia, Shayan; Pagani, Mattia; Liu, Yang; Marpaung, David; Eggleton, Benjamin J

    2016-06-27

    In the microwave domain, signal interference bandstop filters with high extinction and wide stopbands are achieved through destructive interference of two signals. Implementation of this filtering concept using RF photonics will lead to unique filters with high performance, enhanced tuning range and reconfigurability. Here we demonstrate an RF photonic signal interference filter, achieved through the combination of precise synthesis of stimulated Brillouin scattering (SBS) loss with advanced phase and amplitude tailoring of RF modulation sidebands. We achieve a square-shaped, 20-dB extinction RF photonic filter over a tunable bandwidth of up to 1 GHz with a central frequency tuning range of 16 GHz using a low SBS loss of ~3 dB. Wideband destructive interference in this novel filter leads to the decoupling of the filter suppression from its bandwidth and shape factor. This allows the creation of a filter with all-optimized qualities.

  17. Kalman filtering with real-time applications

    CERN Document Server

    Chui, Charles K

    2017-01-01

    This new edition presents a thorough discussion of the mathematical theory and computational schemes of Kalman filtering. The filtering algorithms are derived via different approaches, including a direct method consisting of a series of elementary steps, and an indirect method based on innovation projection. Other topics include Kalman filtering for systems with correlated noise or colored noise, limiting Kalman filtering for time-invariant systems, extended Kalman filtering for nonlinear systems, interval Kalman filtering for uncertain systems, and wavelet Kalman filtering for multiresolution analysis of random signals. Most filtering algorithms are illustrated by using simplified radar tracking examples. The style of the book is informal, and the mathematics is elementary but rigorous. The text is self-contained, suitable for self-study, and accessible to all readers with a minimum knowledge of linear algebra, probability theory, and system engineering. Over 100 exercises and problems with solutions help de...

  18. Theory analysis and experimental research on on-line contamination detecting technology in hydraulic oil

    Institute of Scientific and Technical Information of China (English)

    YAO Cheng-yu; ZHAO Jing-yi; ZHANG Qi-sheng

    2006-01-01

    A system of on-line contamination detecting in hydraulic oil based on silting principle is accomplished, where, metal filter membrane as detector, solenoid as active force to propel piston to blotter and gain differential pressure, step motor drives the membrane to filtrate and counter-flush, LabVIEW as detecting software platform, oil's contamination detecting indirectly by gauging differential pressure. Based on theory analysis, accomplished is relation between contamination level and differential pressure, realizing polynomial curve fitting, and calibration experiment. Field experiment is simulated in the condition of experimental laboratory, has credible precision and real-time performance, which can popularize to the field of production.

  19. Adaptive Filter in SAR Interferometry Derived DEM

    Institute of Scientific and Technical Information of China (English)

    XU Caijun; WANG Hua; WANG Jianglin; GE Linlin

    2005-01-01

    In this paper, the performance of median filter, elevation dependent adaptive sigma median filter, and directionally dependent adaptive sigma median filter are tested on both InSAR Tandem DEM and simulated high-level noisy DEM. Through the comparison, the directionally dependent adaptive sigma median filter is proved to be the most effective one not only in the noise removing but also in the boundary preserve.

  20. Designing a Microstrip coupled line bandpass filter

    Directory of Open Access Journals (Sweden)

    Taoufik Ragani

    2013-09-01

    Full Text Available Bandpass filters play a significant role in wireless communication systems. Transmitted and received signals have to be filtered at a certain center frequency with a specific bandwidth, in this paper, a coupled-line bandpass Filter at the center frequency 6 GHz with the wide bandwidth of 2 GHz. this type of filter can be used in WLAN and other applications for the frequency range of 5-7 GHz.