WorldWideScience

Sample records for recirculating air filtration

  1. Use of Recirculating Ventilation With Dust Filtration to Improve Wintertime Air Quality in a Swine Farrowing Room.

    Science.gov (United States)

    Anthony, T Renée; Altmaier, Ralph; Jones, Samuel; Gassman, Rich; Park, Jae Hong; Peters, Thomas M

    2015-01-01

    The performance of a recirculating ventilation system with dust filtration was evaluated to determine its effectiveness to improve the air quality in a swine farrowing room of a concentrated animal feeding operation (CAFO). Air was exhausted from the room (0.47 m(3) sec(-1); 1000 cfm), treated with a filtration unit (Shaker-Dust Collector), and returned to the farrowing room to reduce dust concentrations while retaining heat necessary for livestock health. The air quality in the room was assessed over a winter, during which time limited fresh air is traditionally brought into the building. Over the study period, dust concentrations ranged from 0.005-0.31 mg m(-3) (respirable) and 0.17-2.09 mg m(-3) (inhalable). In-room dust concentrations were reduced (41% for respirable and 33% for inhalable) with the system in operation, while gas concentrations (ammonia [NH3], hydrogen sulfide [H2S], carbon monoxide [CO], carbon dioxide [CO2]) were unchanged. The position of the exhaust and return air systems provided reasonably uniform contaminant distributions, although the respirable dust concentrations nearest one of the exhaust ducts was statistically higher than other locations in the room, with differences averaging only 0.05 mg m(-3). Throughout the study, CO2 concentrations consistently exceeded 1540 ppm (industry recommendations) and on eight of the 18 study days it exceeded 2500 ppm (50% of the ACGIH TLV), with significantly higher concentrations near a door to a temperature-controlled hallway that was typically often left open. Alternative heaters are recommended to reduce CO2 concentrations in the room. Contaminant concentrations were modeled using production and environmental factors, with NH3 related to the number of sow in the room and outdoor temperatures and CO2 related to the number of piglets and outdoor temperatures. The recirculating ventilation system provided dust reduction without increasing concentrations of hazardous gases.

  2. GSPEL - Air Filtration Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Evaluation capabilities for air filtration devices The Air Filtration Lab provides testing of air filtration devices to demonstrate and validate new or legacy system...

  3. GSPEL - Air Filtration Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Evaluation capabilities for air filtration devicesThe Air Filtration Lab provides testing of air filtration devices to demonstrate and validate new or legacy system...

  4. Filtration Performances of Fabrics for Recirculated Air from Air Conditioning System in Manufacturing Department%卷烟车间空调回风过滤用毛绒滤料的过滤性能

    Institute of Scientific and Technical Information of China (English)

    杨磊; 范晓伟; 张勍; 赵航; 宋高举; 苗芊; 程爱霞; 董富文

    2014-01-01

    In order to assess the cleaning effects of new flocked filter fabrics on the recirculated air from air conditioning system in cigarette manufacturing department, two fabrics of different types were tested and their influencing factors were analyzed. The results showed that: 1) The filtration efficiency of pile fabric was influenced by air velocity more significantly with a standard deviation of filtration efficiency distribution of 21.4%. The filtration efficiency of nap fabric was less affected by air velocity fluctuation, and its highest standard deviation of filtration efficiency distribution was 5.2%. 2) Dust concentration did not affect the running resistance of the two filtration fabrics significantly. 3) The average dust retentivities of nap fabric and pile fabric were 359.2 and 707.1 g/m2, respectively. Though lower in dust retentivity, nap fabric was considered to be more applicable due to its advantages of lower filtration resistance and higher stabilities of filtration efficiency and filtration resistance when air velocity or dust concentration fluctuated.%为研究新型毛绒滤料应用于卷烟车间空调系统过滤段时,对空调回风的净化效果,分析了不同型号毛绒滤料对空调回风粉尘的过滤特性及其影响因素。结果表明:①长毛绒滤料过滤效率受过滤风速的影响较为显著,过滤效率分布的标准差高达21.4%;过滤风速变化时,短毛绒滤料的过滤效率较稳定,过滤效率分布的标准差最高为5.2%。②粉尘浓度对两种毛绒滤料的运行阻力的影响均不明显。③短毛绒滤料平均容尘量359.2 g/m2,小于长毛绒滤料平均容尘量707.1 g/m2。尽管短毛绒滤料容尘量较小,但其过滤阻力、过滤风速变化时过滤效率的稳定性、粉尘浓度变化时过滤阻力的稳定性等性能指标均优于长毛绒滤料。

  5. Air filtration in HVAC systems

    CERN Document Server

    Ginestet, Alain; Tronville, Paolo; Hyttinen, Marko

    2010-01-01

    Air filtration Guidebook will help the designer and user to understand the background and criteria for air filtration, how to select air filters and avoid problems associated with hygienic and other conditions at operation of air filters. The selection of air filters is based on external conditions such as levels of existing pollutants, indoor air quality and energy efficiency requirements.

  6. Reduction of indoor particles concentration using re-circulating filtration units in Danish dwellings

    DEFF Research Database (Denmark)

    Spilak, Michal; Frederiksen, Marie; Karottki, Gabriela D.;

    2012-01-01

    Exposure to particulate matter has been shown to be associated with an increased risk of cardiovascular and respiratory diseases. The indoor environment contributes significantly to the total exposure to air pollution because of the many hours spent here, quantity of sources and low ventilation....... This exposure can be reduced by using re-circulating filtration units, limiting the impact of outdoor pollution penetration, indoor emissions and decomposition of dust on heated surfaces. The objective of this study was to investigate whether reducing the indoor particulate concentration, by means of specially...

  7. Air filtration and indoor air quality

    DEFF Research Database (Denmark)

    Bekö, Gabriel

    2006-01-01

    decent ventilation and air cleaning/air filtration, high indoor air quality cannot be accomplished. The need for effective air filtration has increased with increasing evidence on the hazardous effects of fine particles. Moreover, the air contains gaseous pollutants, removal of which requires various air....... These contradictions should motivate manufacturers and researchers to develop new efficient filtration techniques and/or improve the existing ones. Development of low polluting filtration techniques, which are at the same time easy and inexpensive to maintain is the way forward in the future....

  8. Improving IAQ Via Air Filtration.

    Science.gov (United States)

    Monk, Brian

    1999-01-01

    Provides tips on using air filtration to control indoor air quality in educational facilities, including dedicated spaces with unique air quality conditions such as in libraries, museums and archival storage areas, kitchens and dining areas, and laboratories. The control of particulate contaminants, gaseous contaminants, and moisture buildup are…

  9. Air filtration and indoor air quality

    DEFF Research Database (Denmark)

    Bekö, Gabriel

    2006-01-01

    Demands for better indoor air quality are increasing, since we spend most of our time indoors and we are more and more aware of indoor air pollution. Field studies in different parts of the world have documented that high percentage of occupants in many offices and buildings find the indoor air...... decent ventilation and air cleaning/air filtration, high indoor air quality cannot be accomplished. The need for effective air filtration has increased with increasing evidence on the hazardous effects of fine particles. Moreover, the air contains gaseous pollutants, removal of which requires various air...... cleaning techniques. Supply air filter is one of the key components in the ventilation system. Studies have shown that used ventilation filters themselves can be a significant source of indoor air pollution with consequent impact on perceived air quality, sick building syndrome symptoms and performance...

  10. Optimization of recirculating laminar air flow in operating room air conditioning systems

    Directory of Open Access Journals (Sweden)

    Enver Yalcin

    2016-04-01

    Full Text Available The laminar flow air-conditioning system with 100% fresh air is used in almost all operating rooms without discrimination in Turkey. The laminar flow device which is working with 100% fresh air should be absolutely used in Type 1A operating rooms. However, there is not mandatory to use of 100% fresh air for Type 1B defined as places performed simpler operation. Compared with recirculating laminar flow, energy needs of the laminar flow with 100 % fresh air has been emerged about 40% more than re-circulated air flow. Therefore, when a recirculating laminar flow device is operated instead of laminar flow system with 100% fresh air in the Type 1B operating room, annual energy consumption will be reduced. In this study, in an operating room with recirculating laminar flow, optimal conditions have been investigated in order to obtain laminar flow form by analyzing velocity distributions at various supply velocities by using computational fluid dynamics method (CFD.

  11. The Effect of Ventilation, Filtration and Passive Sorption on Indoor Air Quality in Museum Storage Rooms

    DEFF Research Database (Denmark)

    Ryhl-Svendsen, M.; Clausen, Geo

    2009-01-01

    A study was conducted in five storage rooms at the National Museum of Denmark, in which the effect on indoor air quality of mechanical ventilation, filtration and passive sorption was investigated. Mechanical ventilation and recirculation/filtration was initiated by introducing new ventilation...... and filtration units. Passive sorption was initiated by hanging sheets of sorptive materials oil walls. The control strategies were evaluated in terms of their ability to lower the concentration of internally, generated pollutants, and the indoor-to-outdoor concentration ratio of outdoor pollutants. The overall...... environmental impact for each method was evaluated by the use of material dosimeters. It was found that passive sorption performed better in a small room compared to a large room. Mechanical ventilation and filtration with activated charcoal gave a high protection against ozone, but were less effective...

  12. Simultaneously reducing CO2 and particulate exposures via fractional recirculation of vehicle cabin air

    Science.gov (United States)

    Jung, Heejung S.; Grady, Michael L.; Victoroff, Tristan; Miller, Arthur L.

    2017-01-01

    Prior studies demonstrate that air recirculation can reduce exposure to nanoparticles in vehicle cabins. However when people occupy confined spaces, air recirculation can lead to carbon dioxide (CO2) accumulation which can potentially lead to deleterious effects on cognitive function. This study proposes a fractional air recirculation system for reducing nanoparticle concentration while simultaneously suppressing CO2 levels in the cabin. Several recirculation scenarios were tested using a custom-programmed HVAC (heat, ventilation, air conditioning) unit that varied the recirculation door angle in the test vehicle. Operating the recirculation system with a standard cabin filter reduced particle concentrations to 1000 particles/cm3, although CO2 levels rose to 3000 ppm. When as little as 25% fresh air was introduced (75% recirculation), CO2 levels dropped to 1000 ppm, while particle concentrations remained below 5000 particles/cm3. We found that nanoparticles were removed selectively during recirculation and demonstrated the trade-off between cabin CO2 concentration and cabin particle concentration using fractional air recirculation. Data showed significant increases in CO2 levels during 100% recirculation. For various fan speeds, recirculation fractions of 50–75% maintained lower CO2 levels in the cabin, while still reducing particulate levels. We recommend fractional recirculation as a simple method to reduce occupants’ exposures to particulate matter and CO2 in vehicles. A design with several fractional recirculation settings could allow air exchange adequate for reducing both particulate and CO2 exposures. Developing this technology could lead to reductions in airborne nanoparticle exposure, while also mitigating safety risks from CO2 accumulation. PMID:28781568

  13. Simultaneously reducing CO2 and particulate exposures via fractional recirculation of vehicle cabin air

    Science.gov (United States)

    Jung, Heejung S.; Grady, Michael L.; Victoroff, Tristan; Miller, Arthur L.

    2017-07-01

    Prior studies demonstrate that air recirculation can reduce exposure to nanoparticles in vehicle cabins. However when people occupy confined spaces, air recirculation can lead to carbon dioxide (CO2) accumulation which can potentially lead to deleterious effects on cognitive function. This study proposes a fractional air recirculation system for reducing nanoparticle concentration while simultaneously suppressing CO2 levels in the cabin. Several recirculation scenarios were tested using a custom-programmed HVAC (heat, ventilation, air conditioning) unit that varied the recirculation door angle in the test vehicle. Operating the recirculation system with a standard cabin filter reduced particle concentrations to 1000 particles/cm3, although CO2 levels rose to 3000 ppm. When as little as 25% fresh air was introduced (75% recirculation), CO2 levels dropped to 1000 ppm, while particle concentrations remained below 5000 particles/cm3. We found that nanoparticles were removed selectively during recirculation and demonstrated the trade-off between cabin CO2 concentration and cabin particle concentration using fractional air recirculation. Data showed significant increases in CO2 levels during 100% recirculation. For various fan speeds, recirculation fractions of 50-75% maintained lower CO2 levels in the cabin, while still reducing particulate levels. We recommend fractional recirculation as a simple method to reduce occupants' exposures to particulate matter and CO2 in vehicles. A design with several fractional recirculation settings could allow air exchange adequate for reducing both particulate and CO2 exposures. Developing this technology could lead to reductions in airborne nanoparticle exposure, while also mitigating safety risks from CO2 accumulation.

  14. Four years experience with filtration systems in commercial nurseries for eliminating Phytophthora species from recirculation water

    Science.gov (United States)

    T. Ufer; M. Posner; H.-P. Wessels; S. Wagner; K. Kaminski; T. Brand; Werres S.

    2008-01-01

    In a four year project, three different filtration systems were tested under commercial nursery conditions to eliminate Phytophthora spp. from irrigation water. Five nurseries were involved in the project. Slow sand filtration systems were tested in three nurseries. In the fourth nursery, a filtration system with lava grains (Shieer® Bio filtration)...

  15. Nanofiber filter media for air filtration

    Science.gov (United States)

    Raghavan, Bharath Kumar

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

  16. 21 CFR 211.46 - Ventilation, air filtration, air heating and cooling.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Ventilation, air filtration, air heating and... Buildings and Facilities § 211.46 Ventilation, air filtration, air heating and cooling. (a) Adequate... holding of a drug product. (c) Air filtration systems, including prefilters and particulate matter...

  17. 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

  18. Tailoring Supramolecular Nanofibers for Air Filtration Applications.

    Science.gov (United States)

    Weiss, Daniel; Skrybeck, Dominik; Misslitz, Holger; Nardini, David; Kern, Alexander; Kreger, Klaus; Schmidt, Hans-Werner

    2016-06-15

    The demand of new materials and processes for nanofiber fabrication to enhance the performance of air filters is steadily increasing. Typical approaches to obtain nanofibers are based on top-down processes such as melt blowing, centrifugal spinning, and electrospinning of polymer materials. However, fabrication of polymer nanofibers is limited with respect to either a sufficiently high throughput or the smallest achievable fiber diameter. This study reports comprehensively on a fast and simple bottom-up process to prepare supramolecular nanofibers in situ inside viscose/polyester microfiber nonwovens. Here, selected small molecules of the materials class of 1,3,5-benzenetrisamides are employed. The microfiber-nanofiber composites exhibit a homogeneous nanofiber distribution and morphology throughout the entire nonwoven scaffold. Small changes in molecular structure and processing solvent have a strong influence on the final nanofiber diameter and diameter distribution and, consequently, on the filtration performance. Choosing proper processing conditions, microfiber-nanofiber composites with surprisingly high filtration efficiencies of particulate matter are obtained. In addition, the microfiber-nanofiber composite integrity at elevated temperatures was determined and revealed that the morphology of supramolecular nanofibers is maintained compared to that of the utilized polymer nonwoven.

  19. Coastal recirculation potential affecting air pollutants in Portugal: The role of circulation weather types

    Science.gov (United States)

    Russo, Ana; Gouveia, Célia; Levy, Ilan; Dayan, Uri; Jerez, Sonia; Mendes, Manuel; Trigo, Ricardo

    2016-06-01

    Coastal zones are under increasing development and experience air pollution episodes regularly. These episodes are often related to peaks in local emissions from industry or transportation, but can also be associated with regional transport from neighbour urban areas influenced by land-sea breeze recirculation. This study intends to analyze the relation between circulation weather patterns, air mass recirculation and pollution levels in three coastal airsheds of Portugal (Lisbon, Porto and Sines) based on the application of an objective quantitative measure of potential recirculation. Although ventilation events have a dominant presence throughout the studied 9-yrs period on all the three airsheds, recirculation and stagnation conditions occur frequently. The association between NO2, SO2 and O3 levels and recirculation potential is evident during summer months. Under high average recirculation potential and high variability, NO2 and SO2 levels are higher for the three airsheds, whilst for O3 each airshed responds differently. This indicates a high heterogeneity among the three airsheds in (1) the type of emission - traffic or industry - prevailing for each contaminant, and (2) the response to the various circulation weather patterns and recirculation situations. Irrespectively of that, the proposed methodology, based on iterative K-means clustering, allows to identify which prevailing patterns are associated with high recirculation potential, having the advantage of being applicable to any geographical location.

  20. Effect of room air recirculation delay on the decay rate of tracer gas concentration

    Energy Technology Data Exchange (ETDEWEB)

    Kristoffersen, A.R.; Gadgil, A.J.; Lorenzetti, D.M.

    2004-05-01

    Tracer gas measurements are commonly used to estimate the fresh air exchange rate in a room or building. Published tracer decay methods account for fresh air supply, infiltration, and leaks in ductwork. However, the time delay associated with a ventilation system recirculating tracer back to the room also affects the decay rate. We present an analytical study of tracer gas decay in a well-mixed, mechanically-ventilated room with recirculation. The analysis shows that failing to account for delays can lead to under- or over-estimates of the fresh air supply, depending on whether the decay rate calculation includes the duct volume.

  1. Experimental study on velocity characteristics of recirculation zone in humid air non-premixed flame

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    To examine the effect of the flow field within the recirculation zone on flame structure,the characteristic velocity fields of methane/humid air flame in nonpremixed combustion behind a disc bluff-body burner were experimentally studied by particle image velocimeter (PIV).The results show that two stagnation points exist on the centerline in the recirculation zone flame.However,the distance of the two stagnation points in humid air combustion shortens,and the minimal dimensionless velocity increases compared with the conventional nonhumid air combustion.In addition,the positional curves of the minimal velocities can be partitioned into three phases representing three different flame patterns.The analysis of axial minimal velocities on the centerline and their positions under different co-flow air velocity conditions reveals that fuel-to-air velocity ratio is the crucial parameter that governs humid air combustion flame characteristics.

  2. Some aspects of applying nanostructured materials in air filtration, water filtration and electrical engineering

    Science.gov (United States)

    Kimmer, Dusan; Vincent, Ivo; Lovecka, Lenka; Kazda, Tomas; Giurg, Adam; Skorvan, Ondrej

    2017-05-01

    Nanostructures prepared from nanofibres and nanostructured composites prepared from nanofibres and fillers are gradually becoming increasingly demanded materials for applications in various industrial branches connected with catalysis, environment protection (air filtration, waste water treatment, sound absorption), in biological engineering, electronics (battery separators, electrode materials), etc. Selected applications of these materials prepared in the company SPUR a.s. are summed up in the following presentation.

  3. Possibilities for the filtration of inlet air for gas turbines

    Energy Technology Data Exchange (ETDEWEB)

    Sievert, J.; Reinhardt, H.

    1988-05-01

    Gas turbines require large quantities of air, which are sucked in from the atmosphere. Depending on the weather conditions and the location of the gas turbine the ambient air contains impurities which may lead to damage to or contamination of the blading of the compressors and turbines. In consequence this causes a reduction in output or efficiency. In principle there are several possibilities for the filtration of air sucked in for gas turbines of which the technically relevant ones at the present time are described.

  4. 77 FR 38857 - Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units of Normal...

    Science.gov (United States)

    2012-06-29

    ... COMMISSION Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units of Normal..., Inspection, and Testing Criteria for Air Filtration and Adsorption Units of Normal Atmosphere Cleanup Systems..., entitled, ``Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units of...

  5. 76 FR 82323 - Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units

    Science.gov (United States)

    2011-12-30

    ... COMMISSION Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units AGENCY: Nuclear...-1274, ``Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units of....'' This guide applies to the design, inspection, and testing of air filtration and iodine adsorption...

  6. Reuse & Recirculation of Filter Backwash Water of Water Treatment Water

    Directory of Open Access Journals (Sweden)

    Mangesh L. Jibhakate

    2017-04-01

    Full Text Available Most of the water treatment plant, filtration is done by means of sand filtration process. Due to continuous filtration process, sand pores get clogged and decreases the efficiency. For mitigating such problem, reverse flow of water & air i.e. backwashing process is carried out. To carry out backwashing operation, 4% of treated water has been utilized and will result in muddy water known as backwash water. This backwash water is then discharged into a natural stream or storage tank near the plant for recirculation. The present study includes a trial for the reuse & recirculation of backwash water.

  7. Simulation of C-CP Fiber-Based Air Filtration

    Directory of Open Access Journals (Sweden)

    Christopher L. Cox, Ph.D.

    2008-06-01

    Full Text Available The overall goal of this project is to develop High Efficiency Particulate Air (HEPA filter media, using conventional fiber spinning techniques, with lower pressure drop than current media through the use of shaped fibers. Capillary-channeled polymer (C-CP fibers are gaining interest for use in a range of separations applications. This paper focuses on modeling air filtration where the filter consists of C-CP fibers. A variety of numerical tools are being used in this effort, including a finite element flow solver and Brownian dynamics simulation. Aspects of these techniques in relation to the problem at hand will be described, and simulation results including comparisons to round-fiber filters will be presented. The primary result presented here is the significant difference in predicted pressure drop between a prototype C-CP filter and a round-fiber filter with equal total cross-sectional area.

  8. Air Filtration as Protection against Fouling of Ventilation and Air Conditioning Units

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Lajčíková, Ariana

    2005-01-01

    Currently, air filters are one of the most critical components of air treatment systems as they decontaminate the air delivered to living space. During the operation, however, the level of harmful surface deposits increases, and at certain times, an uncleaned filter can itself become a source...... of undesirable contaminents influencing negatively the IAQ of a living space. This is the phenomenon that has been a subject of the current research. The article presents a new, alternative view on indoor air contaminents and filtration requirements. It describes alternative means of filtration and assesses...... issues of inadequate maintenance and/or long term use of applied air filters. An experimental method of evealuating the air quality by means of chemical analysis and state-of-the-art spectrometer is also described....

  9. Tools for Schools: Filtration for Improved Air Quality. Technical Services Bulletin.

    Science.gov (United States)

    2001

    This product bulletin addresses air pollution control in educational facilities to enhance educational performance, provides air quality recommendations for schools, and examines the filtration needs of various school areas. The types of air particles typically present are highlighted, and the use of proper filtration to control gases and vapors…

  10. Experimental investigation of air pressure affecting filtration performance of fibrous filter sheet.

    Science.gov (United States)

    Xu, Bin; Yu, Xiao; Wu, Ya; Lin, Zhongping

    2017-03-01

    Understanding the effect of air pressure on their filtration performance is important for assessing the effectiveness of fibrous filters under different practical circumstances. The effectiveness of three classes of air filter sheets were investigated in laboratory-based measurements at a wide range of air pressures (60-130 KPa). The filtration efficiency was found most sensitive to the air pressure change at smaller particle sizes. As the air pressure increased from 60 to 130 KPa, significant decrease in filtration efficiency (up to 15%) and increase in pressure drop (up to 90 Pa) were observed. The filtration efficiency of the filter sheet with largest fiber diameter and smallest solid volume fraction was affected most, while the pressure drop of the filter sheet with smallest fiber diameter and largest solid volume fraction was affected most. The effect of air pressure on the filtration efficiency was slightly larger at greater filter face air velocity. However, the effect of air pressure on the pressure drop was negligible. The filtration efficiency and pressure drop were explicitly expressed as functions of the air pressure. Two coefficients were empirically derived and successfully accounted for the effects of air pressure on filtration efficiency and pressure drop.

  11. Integrated photocatalytic filtration array for indoor air quality control.

    Science.gov (United States)

    Denny, Frans; Permana, Eric; Scott, Jason; Wang, Jing; Pui, David Y H; Amal, Rose

    2010-07-15

    Photocatalytic and filtration technologies were integrated to develop a hybrid system capable of removing and oxidizing organic pollutants from an air stream. A fluidized bed aerosol generator (FBAG) was adapted to prepare TiO(2)-loaded ventilation filters for the photodegradation of gas phase ethanol. Compared to a manually loaded filter, the ethanol photodegradation rate constant for the FBAG coated filter increased by 361%. Additionally, the presence of the photogenerated intermediate product, acetaldehyde, was reduced and the time for mineralization to CO(2) was accelerated. These improvements were attributed to the FBAG system providing a more uniform distribution of TiO(2) particles across the filter surface leading to greater accessibility by the UV light. A dual-UV-lamp system, as opposed to a single-lamp system, enhanced photocatalytic filter performance demonstrating the importance of high light irradiance and light distribution across the filter surface. Substituting the blacklight blue lamps with a UV-light-emitting-diode (UV-LED) array led to further improvement as well as suppressed the electrical energy per order (EE/O) by a factor of 6. These improvements derived from the more uniform distribution of light irradiance as well as the higher efficiency of UV-LEDs in converting electrical energy to photons.

  12. 77 FR 60481 - Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units of Post-Accident...

    Science.gov (United States)

    2012-10-03

    ... COMMISSION Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units of Post-Accident..., and Testing Criteria for Air Filtration and Adsorption Units of Post-accident Engineered-Safety... design, inspection, and testing of air filtration and iodine adsorption units of...

  13. The simulation of air recirculation and fire/explosion phenomena within a semiconductor factory.

    Science.gov (United States)

    I, Yet-Pole; Chiu, Yi-Long; Wu, Shi-Jen

    2009-04-30

    The semiconductor industry is the collection of capital-intensive firms that employ a variety of hazardous chemicals and engage in the design and fabrication of semiconductor devices. Owing to its processing characteristics, the fully confined structure of the fabrication area (fab) and the vertical airflow ventilation design restrict the applications of traditional consequence analysis techniques that are commonly used in other industries. The adverse situation also limits the advancement of a fire/explosion prevention design for the industry. In this research, a realistic model of a semiconductor factory with a fab, sub-fabrication area, supply air plenum, and return air plenum structures was constructed and the computational fluid dynamics algorithm was employed to simulate the possible fire/explosion range and its severity. The semiconductor factory has fan module units with high efficiency particulate air filters that can keep the airflow uniform within the cleanroom. This condition was modeled by 25 fans, three layers of porous ceiling, and one layer of porous floor. The obtained results predicted very well the real airflow pattern in the semiconductor factory. Different released gases, leak locations, and leak rates were applied to investigate their influence on the hazard range and severity. Common mitigation measures such as a water spray system and a pressure relief panel were also provided to study their potential effectiveness to relieve thermal radiation and overpressure hazards within a fab. The semiconductor industry can use this simulation procedure as a reference on how to implement a consequence analysis for a flammable gas release accident within an air recirculation cleanroom.

  14. Improving indoor air quality through botanical air filtration in energy efficient residences

    Science.gov (United States)

    Newkirk, Daniel W.

    According to the U.S. EPA, the average American spends 90% of their time indoors where pollutants are two to five times more prevalent than outside. The consequences of these pollutants are estimated to cost the U.S. 125 billion dollars in lost health and productivity. Background literature suggests botanical air filtration may be able to solve this problem by leveraging the natural ability of plants to purify indoor air. By improving indoor air quality, energy consumption can also be reduced by bringing in less outside air to dilute contaminants within the space. A botanical air filter, called the Biowall, was designed and grown aeroponically in a sealed environmental chamber. Precise measurements of air temperature, air humidity, air quality and energy consumption were made under various lighting levels, plant species and watering strategies to optimize its performance. It was found to reduce indoor air pollutants 60 percent and has the potential to reduce heating and cooling energy consumption by 20 to 30 percent.

  15. Antimicrobial nanoparticle-coated electrostatic air filter with high filtration efficiency and low pressure drop.

    Science.gov (United States)

    Sim, Kyoung Mi; Park, Hyun-Seol; Bae, Gwi-Nam; Jung, Jae Hee

    2015-11-15

    In this study, we demonstrated an antimicrobial nanoparticle-coated electrostatic (ES) air filter. Antimicrobial natural-product Sophora flavescens nanoparticles were produced using an aerosol process, and were continuously deposited onto the surface of air filter media. For the electrostatic activation of the filter medium, a corona discharge electrification system was used before and after antimicrobial treatment of the filter. In the antimicrobial treatment process, the deposition efficiency of S. flavescens nanoparticles on the ES filter was ~12% higher than that on the pristine (Non-ES) filter. In the evaluation of filtration performance using test particles (a nanosized KCl aerosol and submicron-sized Staphylococcus epidermidis bioaerosol), the ES filter showed better filtration efficiency than the Non-ES filter. However, antimicrobial treatment with S. flavescens nanoparticles affected the filtration efficiency of the filter differently depending on the size of the test particles. While the filtration efficiency of the KCl nanoparticles was reduced on the ES filter after the antimicrobial treatment, the filtration efficiency was improved after the recharging process. In summary, we prepared an antimicrobial ES air filter with >99% antimicrobial activity, ~92.5% filtration efficiency (for a 300-nm KCl aerosol), and a ~0.8 mmAq pressure drop (at 13 cm/s). This study provides valuable information for the development of a hybrid air purification system that can serve various functions and be used in an indoor environment.

  16. Power plant including an exhaust gas recirculation system for injecting recirculated exhaust gases in the fuel and compressed air of a gas turbine engine

    Science.gov (United States)

    Anand, Ashok Kumar; Nagarjuna Reddy, Thirumala Reddy; Shaffer, Jason Brian; York, William David

    2014-05-13

    A power plant is provided and includes a gas turbine engine having a combustor in which compressed gas and fuel are mixed and combusted, first and second supply lines respectively coupled to the combustor and respectively configured to supply the compressed gas and the fuel to the combustor and an exhaust gas recirculation (EGR) system to re-circulate exhaust gas produced by the gas turbine engine toward the combustor. The EGR system is coupled to the first and second supply lines and configured to combine first and second portions of the re-circulated exhaust gas with the compressed gas and the fuel at the first and second supply lines, respectively.

  17. Efficient and reusable polyamide-56 nanofiber/nets membrane with bimodal structures for air filtration.

    Science.gov (United States)

    Liu, Bowen; Zhang, Shichao; Wang, Xueli; Yu, Jianyong; Ding, Bin

    2015-11-01

    Nanofibrous media that both possess high airborne particle interception efficiency and robust air permeability would have broad technological implications for areas ranging from individual protection and industrial security to environmental governance; however, creating such filtration media has proved extremely challenging. Here we report a strategy to construct the bio-based polyamide-56 nanofiber/nets (PA-56 NFN) membranes with bimodal structures for effective air filtration via one-step electrospinning/netting. The PA-56 membranes are composed of completely covered two-dimensional (2D) ultrathin (∼20 nm) nanonets which are optimized by facilely regulating the solution concentration, and the bonded scaffold fibers constructed cavity structures which are synchronously created by using the CH3COOH inspiration. With integrated properties of small aperture, high porosity, and bonded scaffold, the resulting PA-56 NFN membranes exhibit high filtration efficiency of 99.995%, low pressure drop of 111 Pa, combined with large dust holding capacity of 49 g/m(2) and dust-cleaning regeneration ability, for filtrating ultrafine airborne particles in the most safe manner involving sieving principle and surface filtration. The successful synthesis of PA-56 NFN medium would not only make it a promising candidate for air filtration, but also provide new insights into the design and development of nanonet-based bimodal structures for various applications.

  18. Influence of combined dust reducing carpet and compact air filtration unit on the indoor air quality of a classroom

    NARCIS (Netherlands)

    Scheepers, P.T.J.; Hartog, J.J. de; Reijnaerts, J.; Beckmann, G.; Anzion, R.B.M.; Poels, K.; Godderis, L.

    2015-01-01

    Primary schools mostly rely on natural ventilation but also have an interest in affordable technology to improve indoor air quality (IAQ). Laboratory tests show promising results for dust reducing carpets and compact air filtration systems but there is no information available on the performance of

  19. An indoor air filtration study in homes of elderly

    DEFF Research Database (Denmark)

    Karottki, Dorina Gabriela; Spilak, Michal; Frederiksen, Marie

    2013-01-01

    Exposure to particulate air pollution increases respiratory and cardiovascular morbidity and mortality, especially in elderly, possibly through inflammation and vascular dysfunction.......Exposure to particulate air pollution increases respiratory and cardiovascular morbidity and mortality, especially in elderly, possibly through inflammation and vascular dysfunction....

  20. An indoor air filtration study in homes of elderly

    DEFF Research Database (Denmark)

    Karottki, Dorina Gabriela; Spilak, Michal; Frederiksen, Marie

    2013-01-01

    Exposure to particulate air pollution increases respiratory and cardiovascular morbidity and mortality, especially in elderly, possibly through inflammation and vascular dysfunction.......Exposure to particulate air pollution increases respiratory and cardiovascular morbidity and mortality, especially in elderly, possibly through inflammation and vascular dysfunction....

  1. Air cooled turbine component having an internal filtration system

    Science.gov (United States)

    Beeck, Alexander R [Orlando, FL

    2012-05-15

    A centrifugal particle separator is provided for removing particles such as microscopic dirt or dust particles from the compressed cooling air prior to reaching and cooling the turbine blades or turbine vanes of a turbine engine. The centrifugal particle separator structure has a substantially cylindrical body with an inlet arranged on a periphery of the substantially cylindrical body. Cooling air enters centrifugal particle separator through the separator inlet port having a linear velocity. When the cooling air impinges the substantially cylindrical body, the linear velocity is transformed into a rotational velocity, separating microscopic particles from the cooling air. Microscopic dust particles exit the centrifugal particle separator through a conical outlet and returned to a working medium.

  2. Herbal Extract Incorporated Nanofiber Fabricated by an Electrospinning Technique and its Application to Antimicrobial Air Filtration.

    Science.gov (United States)

    Choi, Jeongan; Yang, Byeong Joon; Bae, Gwi-Nam; Jung, Jae Hee

    2015-11-18

    Recently, with the increased attention to indoor air quality, antimicrobial air filtration techniques have been studied widely to inactivate hazardous airborne microorganisms effectively. In this study, we demonstrate herbal extract incorporated (HEI) nanofibers synthesized by an electrospinning technique and their application to antimicrobial air filtration. As an antimicrobial herbal material, an ethanolic extract of Sophora flavescens, which exhibits great antibacterial activity against pathogens, was mixed with the polymer solution for the electrospinning process. We measured various characteristics of the synthesized HEI nanofibers, such as fiber morphology, fiber size distribution, and thermal stability. For application of the electrospun HEI nanofibers, we made highly effective air filters with 99.99% filtration efficiency and 99.98% antimicrobial activity against Staphylococcus epidermidis. The pressure drop across the HEI nanofiber air filter was 4.75 mmH2O at a face air velocity of 1.79 cm/s. These results will facilitate the implementation of electrospun HEI nanofiber techniques to control air quality and protect against hazardous airborne microorganisms.

  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. Indoor particles affect vascular function in the aged - An air filtration-based intervention study

    DEFF Research Database (Denmark)

    Brauner, E.V.; Forchhammer, L.; Moller, P.

    2008-01-01

    factors, P-selectin, plasma amyloid A, C-reactive protein, fibrinogen, IL-6, tumor necrosis factor-alpha, protein oxidation measured as 2-aminoadipic semialdehyde in plasma, urinary 8-iso-prostaglandin F-2 alpha, and blood pressure. Indoor air filtration significantly improved MVF by 8.1% (95% confidence...

  5. Using experimental designs for modelling of intermittent air filtration process

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Identification of the optimal operating conditions and evaluation of their robustness are critical issues for industrial processes.A standard procedure,for modelling a laboratory-scale wire-to-cylinder electrostatic precipitator and for guiding the research of the set point,is presented.The procedure consists of formulating a set of recommendations regarding the choice of parameter values for electrostatic precipitation.The experiments were carried out on a laboratory cylindrical precipitator,built by one of the authors,with samples of wood particles.The parameters considered are the applied high voltage U,the air flow F,and the quantity of dust in air m.Several"one-factor-at-a-time"followed by factorial composite design experiments were performed,based on the following three-step strategy:1)Identify the domain of variation of the variables;2)Determine the mathematical model of the process outcome:3)Validation of the mathematical model and optimisation of the process.

  6. Epidemiological study of air filtration systems for preventing PRRSV infection in large sow herds.

    Science.gov (United States)

    Alonso, Carmen; Murtaugh, Michael P; Dee, Scott A; Davies, Peter R

    2013-10-01

    Porcine reproductive and respiratory syndrome virus (PRRSV) is the most economically significant pathogen in the US swine industry. Aerosol transmission among herds is a major concern in pig dense regions and filtration of incoming air, in combination with standard biosecurity procedures, has been demonstrated to prevent transmission of PRRSV into susceptible herds. To quantify the impact of air filtration on reducing risk of PRRSV outbreaks, we compared the incidence rate of new PRRSV introductions in 20 filtered and 17 non-filtered control sow herds in a swine dense region of North America during a 7 year study period. Events of novel virus introduction were ascertained by phylogenetic analysis of PRRSV ORF5 gene sequences. Putative new viruses were defined as exogenous (introduced) based on ORF5 nucleotide sequence differences compared to previous farm isolates. The influence of sequence difference cut-off values ranging from 2 to 10% on case definition and relative risk were evaluated. Non-filtered farms incurred about 0.5 outbreaks per year, with a seasonal increase in risk in cooler periods. Baseline risk, prior to filtration, in treatment farms was approximately 0.75 per year, approximately 50% higher than in control farms. Air filtration significantly reduced risk of PRRSV introduction events to 0.06-0.22 outbreaks per year, depending on the cut-off values used to classify a virus isolate as new to the herd. Overall, air filtration led to an approximately 80% reduction in risk of introduction of novel PRRSV, indicating that on large sow farms with good biosecurity in swine-dense regions, approximately four-fifths of PRRSV outbreaks may be attributable to aerosol transmission.

  7. 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.

  8. Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV) systems.

    Science.gov (United States)

    Ng, Bing Feng; Xiong, Jin Wen; Wan, Man Pun

    2017-01-01

    The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM) indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop) that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle clusters to enhance PM capturing efficiency without adding flow resistance in the air distribution ductwork could provide an energy-efficient solution. This pre-conditioning mechanism can be fulfilled by acoustic agglomeration, which is a phenomenon that promotes the coagulation of suspended particles by acoustic waves propagating in the fluid medium. This paper discusses the basic mechanisms of acoustic agglomeration along with influencing factors that could affect the agglomeration efficiency. The feasibility to apply acoustic agglomeration to improve filtration in air-conditioning and mechanical ventilation (ACMV) systems is investigated experimentally in a small-scale wind tunnel. Experimental results indicate that this novel application of acoustic pre-conditioning improves the PM2.5 filtration efficiency of the test filters by up to 10% without introducing additional pressure drop. The fan energy savings from not having to switch to a high capturing efficiency filter largely outstrip the additional energy consumed by the acoustics system. This, as a whole, demonstrates potential energy savings from the combined acoustic-enhanced filtration system without compromising on PM capturing efficiency.

  9. Hierarchically structured polysulfone/titania fibrous membranes with enhanced air filtration performance.

    Science.gov (United States)

    Wan, Huigao; Wang, Na; Yang, Jianmao; Si, Yinsong; Chen, Kun; Ding, Bin; Sun, Gang; El-Newehy, Mohamed; Al-Deyab, Salem S; Yu, Jianyong

    2014-03-01

    Hierarchically structured, superhydrophobic filter medium exhibiting robust filtration performance to airborne particulate were prepared by a facile deposition of electrospun polysulfone/titania nanoparticles (PSU/TiO2 NPs) on a conventional nonwoven substrate. The air permeability, tensile strength and abrasion resistance of pristine PSU fibrous membranes could be finely controlled by regulating the solvent composition and number ratios of jets. By employing the TiO2 NPs incorporation, the pristine PSU fibers were endowed with promising superhydrophobicity with a water contact angle of up to 152°. The quantitative hierarchical roughness analysis using N2 adsorption method has confirmed the major contribution of TiO2 NPs on enhancing the porous structure and surface fractal features with irregular rough structure. Filtration performance studies have revealed that the filtration efficiency and pressure drop of resultant hybrid membranes could be manipulated by tuning the surface composition as well as the hierarchical structures. Furthermore, the as-prepared PSU/TiO2-5 membrane exhibited improved filtration efficiency (99.997%) and pressure drop (45.3 Pa) compared with pristine PSU membrane, which would make them a promising media for fine particle filtration, and a new insight was also provided into the design and development of high performance filter medium based on hierarchical structured fibers.

  10. Air-bubbling, hollow-fiber reactor with cell bleeding and cross-flow filtration.

    Science.gov (United States)

    Nishii, K; Sode, K; Karube, I

    1990-05-01

    Continuous asymmetric reduction of dyhydrooxoisophorone (DOIP) to 4-hydroxy-2,2,6-trimethylcyclo-hexanone (4-HTMCH) was achieved by a thermophilic bacterium Bacillus stearothermophilus NK86-0151. Three reactors were used: an air-bubbling hollow-fiber reactor with cell bleeding and cross-flow filtration, an air-lift reactor, and a CSTR with PAA immobilized cells. The maximum cell concentration of 11.1 g dry wt L(-1) was obtained in an air-bubbling hollow-fiber reactor, while in the other reactors the cell densities were between 3.5 and 4.1 g dry wt L(-1) The optimum bleed ratio was 0.1 at the dilution rate 0.3 h(-1) in the hollow-fiber reactor. The highest viable cell concentration was maintained in the dilution range of 0.4-0.7 h(-1) by a combination of proper cell bleeding and cross-flow filtration. The maximum volumetric productivity of 4-HTMCH reached 826 mg L(-1) h(-1) at the dilution rate 0.54 h(-1). This value was 4 and 2 times higher than those in the air-lift reactor and CSTR, respectively. The increasing viable cell concentration increased the volumetric productivity of 4-HTMCH. A cell free product solution was continuously obtained by cross-flow filtration.

  11. Inverse Problem of Air Filtration of Nanoparticles: Optimal Quality Factors of Fibrous Filters

    Directory of Open Access Journals (Sweden)

    Dahua Shou

    2015-01-01

    Full Text Available Application of nanofibers has become an emerging approach to enhance filtration efficiency, but questions arise about the decrease in Quality factor (QF for certain particles due to the rapidly increasing pressure drop. In this paper, we theoretically investigate the QF of dual-layer filters for filtration of monodisperse and polydisperse nanoparticles. The inverse problem of air filtration, as defined in this work, consists in determining the optimal construction of the two-layer fibrous filter with the maximum QF. In comparison to a single-layer substrate, improved QF values for dual-layer filters are found when a second layer with proper structural parameters is added. The influences of solidity, fiber diameter, filter thickness, face velocity, and particle size on the optimization of QF are studied. The maximum QF values for realistic polydisperse particles with a lognormal size distribution are also found. Furthermore, we propose a modified QF (MQF accounting for the effects of energy cost and flow velocity, which are significant in certain operations. The optimal MQF of the dual-layer filter is found to be over twice that of the first layer. This work provides a quick tool for designing and optimizing fibrous structures with better performance for the air filtration of specific nanoparticles.

  12. RECIRCULATING ACCELERATION

    Energy Technology Data Exchange (ETDEWEB)

    BERG,J.S.; GARREN,A.A.; JOHNSTONE,C.

    2000-04-07

    This paper compares various types of recirculating accelerators, outlining the advantages and disadvantages of various approaches. The accelerators are characterized according to the types of arcs they use: whether there is a single arc for the entire recirculator or there are multiple arcs, and whether the arc(s) are isochronous or non-isochronous.

  13. PTR-MS Assessment of Photocatalytic and Sorption-Based Purification of Recirculated Cabin Air during Simulated 7-h Flights with High Passenger Density

    DEFF Research Database (Denmark)

    Wisthaler, Armin; Strøm-Tejsen, Peter; Fang, Lei

    2007-01-01

    Four different air purification conditions were established in a simulated 3-row 21-seat section of an aircraft cabin: no air purifier; a photocatalytic oxidation unit with an adsorptive prefilter; a second photocatalytic unit with an adsorptive prefil-ter; and a two-stage sorptionbased air filter...... (gas-phase absorption and adsorption). The air purifiers placed in the cabin air recirculation system were commercial prototypes developed for use in aircraft cabin systems. The four conditions were established in balanced order on 4 successive days of each of 4 successive weeks during simulated 7-h...

  14. Experimental development of advanced air filtration media based on electrospun polymer fibers

    Science.gov (United States)

    Ghochaghi, Negar

    Electrospinning is a process by which polymer fibers can be produced using an electrostatically driven fluid jet. Electrospun fibers can be produced at the micro- or nano-scale and are, therefore, very promising for air filtration applications. However, because electrospun fibers are electrically charged, it is difficult to control the morphology of filtration media. Fiber size, alignment and uniformity are very important factors that affect filter performance. The focus of this project is to understand the relationship between filter morphology and performance and to develop new methods to create filtration media with optimum morphology. This study is divided into three focus areas: unimodal and bimodal microscale fibrous media with aligned, orthogonal and random fiber orientations; unimodal and bimodal nanoscale fibers in random orientations; bimodal micrometer and nanometer fiber media with orthogonally aligned orientations. The results indicate that the most efficient filters, which are those with the highest ratio of particle collection efficiency divided by pressure drop, can be obtained through fabricating filters in orthogonal layers of aligned fibers with two different fiber diameters. Moreover, our results show that increasing the number of layers increases the performance of orthogonally layered fibers. Also, controlling fiber spacing in orthogonally layered micrometer fiber media can be an alternative way to study the filtration performance. Finally, such coatings presented throughout this research study can be designed and placed up-stream, down-stream, and/or in between conventional filters.

  15. Biological Chitin-MOF Composites with Hierarchical Pore Systems for Air-Filtration Applications.

    Science.gov (United States)

    Wisser, Dorothea; Wisser, Florian M; Raschke, Silvia; Klein, Nicole; Leistner, Matthias; Grothe, Julia; Brunner, Eike; Kaskel, Stefan

    2015-10-19

    Metal-organic frameworks (MOFs) are promising materials for gas-separation and air-filtration applications. However, for these applications, MOF crystallites need to be incorporated in robust and manageable support materials. We used chitin-based networks from a marine sponge as a non-toxic, biodegradable, and low-weight support material for MOF deposition. The structural properties of the material favor predominant nucleation of the MOF crystallites at the inside of the hollow fibers. This composite has a hierarchical pore system with surface areas up to 800 m(2)  g(-1) and pore volumes of 3.6 cm(3)  g(-1) , allowing good transport kinetics and a very high loading of the active material. Ammonia break-through experiments highlight the accessibility of the MOF crystallites and the adsorption potential of the composite indicating their high potential for filtration applications for toxic industrial gases.

  16. Influence of thermal flow field of cooling tower on recirculation ratio of a direct air-cooled system for a power plant

    Institute of Scientific and Technical Information of China (English)

    Zhao Wanli; Liu Peiqing

    2008-01-01

    In order to get thermal flow field of direct air-cooled system,the hot water was supplied to the model of direct air-cooled condenser(ACC).The particle image velocimetery(PIV)experiments were carried out to get thermal flow field of a ACC under different conditions in low velocity wind tunnel,at the same time,the recirculation ratio at cooling tower was measured,so the relationship between flow field characteristics and recirculation ratio of cooling tower can be discussed.From the results we can see that the flow field configuration around cooling tower has great effects on average recirculation ratio under cooling tower.The eddy formed around cooling tower is a key reason that recireulation pro-duces.The eddy intensity relates to velocity magnitude and direction angle,and the configuration of eddy lies on the ge-ometry size of cooling tower.So changing the flow field configuration around cooling tower reasonably can decrease recir-culation ratio under cooling tower,and heat dispel effect of ACC can also be improved.

  17. Mixed air ceilings for surgical rooms with recirculating blowers; Mischluftdecke fuer OP-Raeume mit Umluftventilatoren

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2001-07-01

    Ceilings of modern surgery rooms must have a size of about 3,200 x 3,200 mm for a laminar displacement flow of 0.18 - 0.25 m/s. air volume flows of more than 9,000 cubic metres per hour are required. Not all surgical wards have the capacity for sufficiently large air ducts for central air supply. [German] Die moderne Chirurgie verlangt OP-Zuluftdecken mit Groessen von etwa 3 200 x 3 200 mm, die eine laminare Verdraengungsstroemung im Geschwindigkeitsbereich von etwa 0,18 bis 0,25 m/s sichern. Hierbei werden Zuluft-Volumenstroeme bis ueber 9 000 m{sup 3}/h erforderlich. Nicht alle OP-Abteilungen lassen die Verlegung der entsprechend grossen Luftleitungen fuer zentrale Luftversorgung zu. (orig.)

  18. Validation for a recirculation model.

    Science.gov (United States)

    LaPuma, P T

    2001-04-01

    Recent Clean Air Act regulations designed to reduce volatile organic compound (VOC) emissions have placed new restrictions on painting operations. Treating large volumes of air which contain dilute quantities of VOCs can be expensive. Recirculating some fraction of the air allows an operator to comply with environmental regulations at reduced cost. However, there is a potential impact on employee safety because indoor pollutants will inevitably increase when air is recirculated. A computer model was developed, written in Microsoft Excel 97, to predict compliance costs and indoor air concentration changes with respect to changes in the level of recirculation for a given facility. The model predicts indoor air concentrations based on product usage and mass balance equations. This article validates the recirculation model using data collected from a C-130 aircraft painting facility at Hill Air Force Base, Utah. Air sampling data and air control cost quotes from vendors were collected for the Hill AFB painting facility and compared to the model's predictions. The model's predictions for strontium chromate and isocyanate air concentrations were generally between the maximum and minimum air sampling points with a tendency to predict near the maximum sampling points. The model's capital cost predictions for a thermal VOC control device ranged from a 14 percent underestimate to a 50 percent overestimate of the average cost quotes. A sensitivity analysis of the variables is also included. The model is demonstrated to be a good evaluation tool in understanding the impact of recirculation.

  19. Air Filtration as Protection against Fouling of Ventilation and Air Conditioning Units

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Lajčíková, Ariana

    2005-01-01

    Currently, air filters are one of the most critical components of air treatment systems as they decontaminate the air delivered to living space. During the operation, however, the level of harmful surface deposits increases, and at certain times, an uncleaned filter can itself become a source...

  20. Combustion-gas recirculation system

    Science.gov (United States)

    Baldwin, Darryl Dean

    2007-10-09

    A combustion-gas recirculation system has a mixing chamber with a mixing-chamber inlet and a mixing-chamber outlet. The combustion-gas recirculation system may further include a duct connected to the mixing-chamber inlet. Additionally, the combustion-gas recirculation system may include an open inlet channel with a solid outer wall. The open inlet channel may extend into the mixing chamber such that an end of the open inlet channel is disposed between the mixing-chamber inlet and the mixing-chamber outlet. Furthermore, air within the open inlet channel may be at a pressure near or below atmospheric pressure.

  1. Soil-based filtration technology for air purification: potentials for environmental and space life support application

    Science.gov (United States)

    Nelson, Mark; Bohn, Hinrich

    Soil biofiltration, also known as Soil bed reactor (SBR), technology was originally developed in Germany to take advantage of the diversity in microbial mechanisms to control gases producing malodor in industrial processes. The approach has since gained wider international acceptance and seen numerous improvements, for example, by the use of high-organic compost beds to maximize microbial processes. This paper reviews the basic mechanisms which underlay soil processes involved in air purification, advantages and limitations of the technology and the cur-rent research status of the approach. Soil biofiltration has lower capital and operating/energetic costs than conventional technologies and is well adapted to handle contaminants in moderate concentrations. The systems can be engineered to optimize efficiency though manipulation of temperature, pH, moisture content, soil organic matter and airflow rates. SBR technology was modified for application in the Biosphere 2 project, which demonstrated in preparatory research with a number of closed system testbeds that soil could also support crop plants while also serving as soil filters with air pumps to push air through the soil. This Biosphere 2 research demonstrated in several closed system testbeds that a number of important trace gases could be kept under control and led to the engineering of the entire agricultural soil of Biosphere 2 to serve as a soil filtration unit for the facility. Soil biofiltration, coupled with food crop produc-tion, as a component of bioregenerative space life support systems has the advantages of lower energy use and avoidance of the consumables required for other air purification approaches. Expanding use of soil biofiltration can aid a number of environmental applications, from the mitigation of indoor air pollution, improvement of industrial air emissions and prevention of accidental release of toxic gases.

  2. Selection of optimized air pollutant filtration technologies for petrochemical industries through multiple-attribute decision-making.

    Science.gov (United States)

    Moridi, Parvin; Atabi, Farideh; Nouri, Jafar; Yarahmadi, Rasoul

    2017-07-15

    Selecting cost-effective and efficient air filtration technologies that ensure sustainable development is a challenge to national, regional and local policy makers. Various factors such as efficiency, maintainability, and design of the developed devices can affect the selection of optimized technologies. The present study aimed to select optimal technologies for air filtration devices in petrochemical industries through a multi-criteria decision-making (MADM) method based on a fuzzy model of Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). Five criteria (filtration efficiency, cost, maintainability, designability, and size) were used to rank air pollution control technologies designed to eliminate particulate matter (PM), volatile organic compounds (VOCs), and ammonia (NH3). According to the results, the research criteria had different weights for different air pollutants. High-efficiency particulate air (HEPA + pre collector) filters, plasma chemistry, and chemical absorption were identified as the most appropriate filtration methods for PM, VOCs, and NH3, respectively (coefficients = 0.923, 0.9586, and 0.867, respectively). Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. 再循环对飞机空调系统性能影响分析%Analysis of the Recirculation Impact to Aircraft Air Conditioning Performances

    Institute of Scientific and Technical Information of China (English)

    南国鹏; 孙学德

    2012-01-01

    For the development of the commercial aircraft environment control system (ECS) ,with the thermodynamics theory, established mathematical models of the recirculation system and the simulation software has been developed. Using this simulation, analyzed the impact of the recirculation to the steady and dynamic performances of air conditioning system. Then the design principle and parameters scope of the recirculation system are concluded. The analysis result is directly applied to design the ECS of the certain commercial aircraft, the good achievement is gotten.%结合国内民航客机环境控制系统的研制需求,利用热力学理论建立了再循环系统各附件数学模型,并编制了系统仿真程序。通过仿真对再循环系统设计参数与空调系统的稳、动态指标之间的影响因素进行了研究,并得出再循环系统的设计原则和参数选取范围。将其结论应用于某型飞机环境控制系统的研制中.效果良好。

  4. Performance modeling of industrial gas turbines with inlet air filtration system

    Directory of Open Access Journals (Sweden)

    Samuel O. Effiom

    2015-03-01

    Full Text Available The effect of inlet air filtration on the performance of two industrial gas turbines (GT is presented. Two GTs were modeled similar to GE LM2500+ and Alstom GT13 E2-2012, using TURBOMATCH and chosen to operate at environmental conditions of Usan offshore oilfield and Maiduguri dessert in Nigeria. The inlet pressure recovered (Precov from the selected filters used in Usan offshore, and Maiduguri ranged between 98.36≤Precov≤99.51% and 98.67≤Precov≤99.56% respectively. At reduced inlet Precov by 98.36% (1.66 kPa and, at a temperature above 15 °C (ISA, a reduction of 16.9%, and 7.3% of power output and efficiency was obtained using GT13 E2-2012, while a decrease of 14.8% and 4.7% exist for power output and efficiency with GE LM2500+. In addition, a reduction in mass flow rate of air and fuel under the same condition was between 4.3≤mair≤10.6% and 10.4≤mfuel≤11.5% for GT13 E2-2012 and GE LM2500+, correspondingly. However, the GE LM2500+ was more predisposed to intake pressure drops since it functioned at a higher overall pressure ratio. The results obtained were found worthwhile and could be the basis for filter selection and efficient compressor housing design in the locations concerned.

  5. The impact of recirculation, ventilation and filters on secondary organic aerosols generated by indoor chemistry

    DEFF Research Database (Denmark)

    Fadeyi, M.O.; Weschler, Charles J.; Tham, K.W.

    2009-01-01

    This study examined the impact of recirculation rates (7 and 14 h(-1)), ventilation rates (1 and 2 h(-1)), and filtration on secondary organic aerosols (SOAs) generated by ozone of outdoor origin reacting with limonene of indoor origin. Experiments were conducted within a recirculating air handling...... system that serviced an unoccupied, 236 m(3) environmental chamber configured to simulate an office; either no filter, a new filter or a used filter was located downstream of where outdoor air mixed with return air. For otherwise comparable conditions, the SOA number and mass concentrations......, but this was more than offset by the increased dilution of SOA derived from ozone-initiated chemistry. The presence of a particle filter (new or used) strikingly lowered SOA number and mass concentrations compared with conditions when no filter was present. Even though the particle filter in this study had only 35...

  6. Evaluation of the long-term effect of air filtration on the occurrence of new PRRSV infections in large breeding herds in swine-dense regions.

    Science.gov (United States)

    Dee, Scott; Cano, Jean Paul; Spronk, Gordon; Reicks, Darwin; Ruen, Paul; Pitkin, Andrea; Polson, Dale

    2012-05-01

    Airborne transmission of porcine reproductive and respiratory syndrome virus (PRRSV) is a risk factor for the infection of susceptible populations. Therefore, a long‑term sustainability study of air filtration as a means to reduce this risk was conducted. Participating herds (n = 38) were organized into 4 independent cohorts and the effect of air filtration on the occurrence of new PRRSV infections was analyzed at 3 different levels from September 2008 to January 2012 including the likelihood of infection in contemporary filtered and non-filtered herds, the likelihood of infection before and after implementation of filtration and the time to failure in filtered and non-filtered herds. Results indicated that new PRRSV infections in filtered breeding herds were significantly lower than in contemporary non-filtered control herds (P filtration was 7.97 times higher than the odds after filtration was initiated (P filtration on reducing the occurrence of new PRRSV infections in the study population was demonstrated.

  7. Improvement of emissions and performance by using of air jet, exhaust gas re-circulation and insulation methods in a direct injection diesel engine

    Directory of Open Access Journals (Sweden)

    Jafarmadara S.

    2013-01-01

    Full Text Available This article investigates the improvement of operation characteristics and emissions reduction by means of creating an air-cell inside the piston body, exhaust gases recirculating and insulating combustion chamber in a direct injection diesel engine simultaneously. The engine considered is a caterpillar 3401 which was modeled with an air-cell included as part of the piston geometry. This air-cell demonstrates that air injection in late combustion period can be effective in a significant reduction of Soot emission while cold EGR can be effective in reduction of NOx emission. Also for increasing of performance parameters, combustion chamber with air-cell is insulated. The analyses are carried out at part (75% of full load and full load conditions at the same engine speed 1600 rpm. The obtained results indicate that creating the air-cell has a slight effect on improvement of performance parameters and it has significantly effect on Soot reduction. The air-cell decreases the Soot pollutant as a factor of two at both part and full load conditions. Also, the adding 5% of cold EGR in inlet air decreases NOx by about half and insulating the engine increases the power and IMEP by about 7.7% and 8.5% and decreases the ISFC by about 7.5% at part load and increases power and IMEP by 8.5%, 8.5% and decreases ISFC by 8% at full load condition, respectively. Using this method, it was possible to control emissions formation and increase performance parameters simultaneously. The predicted results for mean in-cylinder pressure and emissions are compared to the corresponding experimental results and show good agreements.

  8. Design and Characterization of Electrospun Polyamide Nanofiber Media for Air Filtration Applications

    NARCIS (Netherlands)

    Matulevicius, J; Kliucininkas, L; Martuzevicius, D; Krugly, E; Tichonovas, M.; Baltrusaitis, Jonas

    2014-01-01

    Electrospun polyamide 6 (PA 6) and polyamide 6/6 (PA 6/6) nanofibers were produced in order to investigate their experimental characteristics with the goal of obtaining filtration relevant fiber media. The experimental design model of each PA nanofibers contained the following variables: polymer con

  9. Design and Characterization of Electrospun Polyamide Nanofiber Media for Air Filtration Applications

    Directory of Open Access Journals (Sweden)

    Jonas Matulevicius

    2014-01-01

    Full Text Available Electrospun polyamide 6 (PA 6 and polyamide 6/6 (PA 6/6 nanofibers were produced in order to investigate their experimental characteristics with the goal of obtaining filtration relevant fiber media. The experimental design model of each PA nanofibers contained the following variables: polymer concentration, ratio of solvents, nanofiber media collection time, tip-to-collector distance, and the deposition voltage. The average diameter of the fibers, their morphology, basis weight, thickness, and resulting media solidity were investigated. Effects of each variable on the essential characteristics of PA 6/6 and PA 6 nanofiber media were studied. The comparative analysis of the obtained PA 6/6 and PA 6 nanofiber characteristics revealed that PA 6/6 had higher potential to be used in filtration applications. Based on the experimental results, the graphical representation—response surfaces—for obtaining nanofiber media with the desirable fiber diameter and basis weight characteristics were derived. Based on the modelling results the nanofiber filter media (mats were fabricated. Filtration results revealed that nanofiber filter media electrospun from PA6/6 8% (w/vol solutions with the smallest fiber diameters (62–66 nm had the highest filtration efficiency (PA6/6_30 = 84.9–90.9% and the highest quality factor (PA6/6_10 = 0.0486–0.0749 Pa−1.

  10. Experimental investigation of the formaldehyde removal mechanisms in a dynamic botanical filtration system for indoor air purification.

    Science.gov (United States)

    Wang, Zhiqiang; Pei, Jingjing; Zhang, Jensen S

    2014-09-15

    Botanical filtration has been proved to be effective for indoor gas pollutant removal. To understand the roles of different transport, storage and removal mechanism by a dynamic botanical air filter, a series of experimental investigations were designed and conducted in this paper. Golden Pothos (Epipremnum aureum) plants was selected for test, and its original soil or activated/pebbles root bed was used in different test cases. It was found that flowing air through the root bed with microbes dynamically was essential to obtain meaningful formaldehyde removal efficiency. For static potted plant as normally place in rooms, the clean air delivery rate (CADR), which is often used to quantify the air cleaning ability of portable air cleaners, was only ∼ 5.1m(3)/h per m(2) bed, while when dynamically with air flow through the bed, the CADR increased to ∼ 233 m(3)/h per m(2) bed. The calculated CADR due to microbial activity is ∼ 108 m(3)/h per m(2) bed. Moisture in the root bed also played an important role, both for maintaining a favorable living condition for microbes and for absorbing water-soluble compounds such as formaldehyde. The role of the plant was to introduce and maintain a favorable microbe community which effectively degraded the volatile organic compounds adsorbed or absorbed by the root bed. The presence of the plant increased the removal efficiency by a factor of two based on the results from the bench-scale root bed experiments.

  11. Space Characteristics of Exhaust Plume Recirculation Flow Ratios for Air-Cooled Condensers at Ambient Winds%风场影响下直接空冷系统热风回流率的空间分布特性

    Institute of Scientific and Technical Information of China (English)

    杨立军; 杜小泽; 杨勇平

    2011-01-01

    Ambient winds may lead to the worsened exhaust plume recirculation flows and the deteriorated heat transfer performances of the air-cooled condensers in a power plant.It can be of use for the design and operation of the direct dry cooling system to investigate the space characteristics of the exhaust plume recirculation flow ratios for the air-cooled condensers at ambient winds.On the basis of the representative 2×600 MW direct dry cooling power plant,the flow and temperature fields of the cooling air are presented and the exhaust plume recirculation flow ratios of the air-cooled condensers and condenser cells are calculated by using the numerical simulation.The results show that the exhaust plume recirculation flows are enhanced owing to the increase of the wind speeds and vary widely with the wind directions.The wind blowing from the main buildings is most unfavorable for the exhaust plume recirculation flows.The exhaust plume recirculation flow ratios present space-dependent characteristics and the conspicuous differences are presented among the condenser cells at various locations.The upwind condenser cells generally have more disadvantageous plume recirculation flows.%环境风场影响下,电站直接空冷系统热风回流加剧,传热性能恶化。掌握风场作用下直接空冷系统热风回流率的空间分布特性,可为空冷系统的设计和运行提供理论依据。以典型2×600 MW直接空冷电站为例,通过数值模拟获得了冷却空气流场和温度场,分别计算了空冷岛和各个空冷单元的热风回流率。计算结果表明,随环境风速增加,空冷岛热风回流率升高,并随风向发生显著变化,炉后来风时空冷岛热风回流最为严重。空冷单元热风回流率呈现空间分布特性,风场不同区域空冷单元热风回流存在显著差异,处于风场上游空冷单元通常具有更大的热风回流率。

  12. Electret Polyvinylidene Fluoride Nanofibers Hybridized by Polytetrafluoroethylene Nanoparticles for High-Efficiency Air Filtration.

    Science.gov (United States)

    Wang, Shan; Zhao, Xinglei; Yin, Xia; Yu, Jianyong; Ding, Bin

    2016-09-14

    Airborne particulate matter (PM) pollution has become a severe environmental concern calling for electret fibrous materials with high filtration efficiency and low pressure drop. However, restraining the dissipation of the electric charges in service to ensure the stabilized electrostatic force of the fibers for effectively adsorbing particles is extremely important and also challenging. Herein, we report novel electret nanofibrous membranes with numerous charges and desirable charge stability using polyvinylidene fluoride (PVDF) as the matrix polymer and polytetrafluoroethylene nanoparticles (PTFE NPs) as an inspiring charge enhancer through the in situ charging technology of electrospinning. Benefiting from the employment of PTFE NPs and optimized injection energy, the fibrous membranes are endowed with elevated surface potentials from 0.42 to 3.63 kV and reduced decrement of charges from 75.4 to 17.5%, which contribute to the ameliorative stability of filtration efficiency. Significantly, an electret mechanism is proposed, while deepened depth of the energy level and incremental polarized dipole charges with increasing PTFE NP concentrations and injection energy have been confirmed through the measurement of open-circuit thermally stimulated discharge and surface potential decay. Ultimately, the resultant fibrous membrane exhibited a high filtration efficiency of 99.972%, a low pressure drop of 57 Pa, a satisfactory quality factor of 0.14 Pa(-1), and superior long-term service performance. The successful fabrication of such an intriguing material may provide a new approach for the design and development of electret materials for PM2.5 governance.

  13. Is the use of particle air filtration justified? Costs and benefits of filtration with regard to health effects, building cleaning and occupant productivity

    DEFF Research Database (Denmark)

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

    2008-01-01

    Estimates of costs and the corresponding benefits of particle filtration have been derived for a standard office building. Reduction in occupants’ exposure to particles during their workday is anticipated to reduce their morbidity and mortality. Filtration may also reduce the costs associated......, the sensitivity of the results to these parameters was evaluated as part of this study. The study also acknowledges that the benefits-to-costs ratio depends on the perspective of the stakeholder: the employer renting the building is impacted by occupant performance and building energy costs; the building owner...... is impacted by maintenance of the building and its HVAC system; society is impacted by the employees’ health and welfare. Regardless of perspective, particle filtration is anticipated to lead to annual savings significantly exceeding the running costs for filtration. However, economic losses resulting from...

  14. Exhaust gas recirculation in a homogeneous charge compression ignition engine

    Science.gov (United States)

    Duffy, Kevin P.; Kieser, Andrew J.; Rodman, Anthony; Liechty, Michael P.; Hergart, Carl-Anders; Hardy, William L.

    2008-05-27

    A homogeneous charge compression ignition engine operates by injecting liquid fuel directly in a combustion chamber, and mixing the fuel with recirculated exhaust and fresh air through an auto ignition condition of the fuel. The engine includes at least one turbocharger for extracting energy from the engine exhaust and using that energy to boost intake pressure of recirculated exhaust gas and fresh air. Elevated proportions of exhaust gas recirculated to the engine are attained by throttling the fresh air inlet supply. These elevated exhaust gas recirculation rates allow the HCCI engine to be operated at higher speeds and loads rendering the HCCI engine a more viable alternative to a conventional diesel engine.

  15. Filtration effectiveness of HVAC systems at near-roadway schools.

    Science.gov (United States)

    McCarthy, M C; Ludwig, J F; Brown, S G; Vaughn, D L; Roberts, P T

    2013-06-01

    Concern for the exposure of children attending schools located near busy roadways to toxic, traffic-related air pollutants has raised questions regarding the environmental benefits of advanced heating, ventilation, and air-conditioning (HVAC) filtration systems for near-road pollution. Levels of black carbon and gaseous pollutants were measured at three indoor classroom sites and at seven outdoor monitoring sites at Las Vegas schools. Initial HVAC filtration systems effected a 31-66% reduction in black carbon particle concentrations inside three schools compared with ambient air concentrations. After improved filtration systems were installed, black carbon particle concentrations were reduced by 74-97% inside three classrooms relative to ambient air concentrations. Average black carbon particle concentrations inside the schools with improved filtration systems were lower than typical ambient Las Vegas concentrations by 49-96%. Gaseous pollutants were higher indoors than outdoors. The higher indoor concentrations most likely originated at least partially from indoor sources, which were not targeted as part of this intervention. Recent literature has demonstrated adverse health effects in subjects exposed to ambient air near major roadways. Current smart growth planning and infill development often require that buildings such as schools are built near major roadways. Improving the filtration systems of a school's HVAC system was shown to decrease children's exposure to near-roadway diesel particulate matter. However, reducing exposure to the gas-phase air toxics, which primarily originated from indoor sources, may require multiple filter passes on recirculated air. © 2012 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

  16. Ionizer assisted air filtration for collection of submicron and ultrafine particles-evaluation of long-term performance and influencing factors.

    Science.gov (United States)

    Shi, Bingbing; Ekberg, Lars

    2015-06-02

    Previous research has demonstrated that unipolar ionization can enhance the filter performance to collect airborne particles, aeroallergens, and airborne microorganisms, without affecting the filter pressure drop. However, there is a lack of research on the long-term system performance as well as the influence of environmental and operational parameters. In this paper, both field and laboratory tests were carried out to evaluate the long-term particle collection efficiency of a synthetic filter of class M6 with and without ionization. The effect of air velocity, temperature, relative humidity, and particle concentration were further investigated in laboratory tests. Results showed that ionization enhanced the filtration efficiency by 40%-units during most of the operation time. When the ionization system was managed by periodically switching the ionizer polarity, the filtration efficiency against PM0.3-0.5 was maintained above 50% during half a year. Furthermore, the pressure drop of the ionizer-assisted M6 filter was 25-30% lower than that of a filter of class F7. The evaluation of various influencing factors demonstrated that (1) air moisture reduced the increase of filtration efficiency; (2) higher upstream particle concentration and air velocity decreased the filtration efficiency; and (3) the air temperature had very limited effect on the filtration efficiency.

  17. Inter-laboratory performance between two nanoparticle air filtration systems using scanning mobility particle analyzers

    Science.gov (United States)

    Lore, Michael B.; Sambol, Anthony R.; Japuntich, Daniel A.; Franklin, Luke M.; Hinrichs, Steven H.

    2011-04-01

    The performance of two aerosol testing systems, at two different laboratories (University of Nebraska Medical Center—UNMC and 3M Company), was compared to evaluate which calibration procedures minimized variability in filter testing of nanoparticles. Both charged electret and uncharged flat-web fibrous filters were used with Scanning Mobility Particle Sizers to give upstream and downstream size distributions and calculate filter penetration. Challenge aerosols were polydisperse nanoparticles of sodium chloride (NaCl) ranging from approximately 10-300 nm and monodisperse polystyrene latex (PSL) spheres of preselected sizes, including 40, 60, 100, and 200 nm. The implementation of optimized procedures resulted in comparable filtration performance at the two testing sites with challenges of NaCl particles and PSL spheres. The penetration results for the uncharged filter were nearly identical for both challenges, while lower penetration through the charged filter was observed with NaCl aerosol, probably due to differences in NaCl and PSL dielectric constants. Results showed that reproducible, comparable nanoparticle filtration data could be achieved between two separate laboratories when sources of error and proper calibration procedures were addressed.

  18. A Novel Hierarchical Structured Poly(lactic acid/Titania Fibrous Membrane with Excellent Antibacterial Activity and Air Filtration Performance

    Directory of Open Access Journals (Sweden)

    Zhe Wang

    2016-01-01

    Full Text Available Hybrid poly(lactic acid/titania (PLA/TiO2 fibrous membranes exhibiting excellent air filtration performance and good antibacterial activity were prepared via the electrospinning technique. By varying the composition of the precursor solutions and the relative humidity, the morphologies of PLA/TiO2 fibers, including the nanopores and nanometer-scale protrusions on the surface of the fibers, could be regulated. The distribution of nanopores and TiO2 nanoparticles on the surface of PLA/TiO2 fibers was investigated. Nitrogen adsorption-desorption analysis revealed that nanopores and nanometer-scale protrusions play an important role in improving the specific surface area and nanopore volume of the relevant PLA/TiO2 fibrous membrane. Filtration performance tests conducted by measuring the penetration of sodium chloride aerosol particles with a 260 nm mass median diameter indicated that fibers with a high surface roughness, large specific surface area, and large nanopore volume greatly improved the particle capture efficiency and facilitated the penetration of airflow. Furthermore, the introduction of TiO2 nanoparticles endows the relevant fibrous membrane with antibacterial properties. The as-prepared PLA/TiO2 fibrous membrane loaded with 1.75 wt% TiO2 nanoparticles formed at a relative humidity of 45% exhibited a high filtration efficiency (99.996% and a relatively low pressure drop (128.7 Pa, as well as a high antibacterial activity of 99.5%.

  19. Electric air filtration: theory, laboratory studies, hardware development, and field evaluations

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, W.; Biermann, A.; Kuhl, W.; Lum, B.; Bogdanoff, A.; Hebard, H.; Hall, M.; Banks, D.; Mazumder, M.; Johnson, J.

    1983-09-01

    We summarize the results of a seven-year research project for the US Department of Energy (DOE) to develop electric air filters that extend the service life of high-efficiency particulate air (HEPA) filters used in the nuclear industry. This project was unique to Lawrence Livermore National Laboratory (LLNL), and it entailed comprehensive theory, laboratory studies, and hardware development. We present our work in three major areas: (1) theory of and instrumentation for filter test methods, (2) theoretical and laboratory studies of electric air filters, and (3) development and evaluation of eight experimental electric air filters.

  20. Self-Driven Desalination and Advanced Treatment of Wastewater in a Modularized Filtration Air Cathode Microbial Desalination Cell.

    Science.gov (United States)

    Zuo, Kuichang; Wang, Zhen; Chen, Xi; Zhang, Xiaoyuan; Zuo, Jiaolan; Liang, Peng; Huang, Xia

    2016-07-05

    Microbial desalination cells (MDCs) extract organic energy from wastewater for in situ desalination of saline water. However, to desalinate salt water, traditional MDCs often require an anolyte (wastewater) and a catholyte (other synthetic water) to produce electricity. Correspondingly, the traditional MDCs also produced anode effluent and cathode effluent, and may produce a concentrate solution, resulting in a low production of diluate. In this study, nitrogen-doped carbon nanotube membranes and Pt carbon cloths were utilized as filtration material and cathode to fabricate a modularized filtration air cathode MDC (F-MDC). With real wastewater flowing from anode to cathode, and finally to the middle membrane stack, the diluate volume production reached 82.4%, with the removal efficiency of salinity and chemical oxygen demand (COD) reached 93.6% and 97.3% respectively. The final diluate conductivity was 68 ± 12 μS/cm, and the turbidity was 0.41 NTU, which were sufficient for boiler supplementary or industrial cooling. The concentrate production was only 17.6%, and almost all the phosphorus and salt, and most of the nitrogen were recovered, potentially allowing the recovery of nutrients and other chemicals. These results show the potential utility of the modularized F-MDC in the application of municipal wastewater advanced treatment and self-driven desalination.

  1. Gravimetric Analysis of Particulate Matter using Air Samplers Housing Internal Filtration Capsules

    OpenAIRE

    O'Connor, Sean; O'Connor, Paula Fey; Feng, H. Amy; Ashley, Kevin

    2014-01-01

    An evaluation was carried out to investigate the suitability of polyvinyl chloride (PVC) internal capsules, housed within air sampling devices, for gravimetric analysis of airborne particles collected in workplaces. Experiments were carried out using blank PVC capsules and PVC capsules spiked with 0,1 – 4 mg of National Institute of Standards and Technology Standard Reference Material® (NIST SRM) 1648 (Urban Particulate Matter) and Arizona Road Dust (Air Cleaner Test Dust). The capsules were ...

  2. Case Studies of Air Filtration at Microscales: Micro- and Nanofiber Media

    Directory of Open Access Journals (Sweden)

    Benoît Mazé, Ph.D.

    2008-06-01

    Full Text Available In this work, 3-D fibrous geometries are developed to resemble the microstructure of spun-bonded and electrospun filters media and used here to simulate their filtration efficiency and pressure drop. For the sake of simplicity, a continuum flow theory was considered to prevail for the case of spun-bonded media (microfiber media whereas our electrospun media (nanofiber media were assumed to be in a free molecular flow regime.Our simulations results are in good general agreement with the experimental data. Especially, in predicting media’s pressure drop, our results show better predictions when compared to some of the existing models. We also quantitatively demonstrated that by decreasing the fiber diameter, the minimum collection efficiency of the media having identical pressure drops increases. This effect is accompanied by a decrease in the particle diameter associated with these minimum efficiencies – the most penetrating particle diameter. Studying the influence of the gas temperature, we showed that filter’s efficiency increases as the gas temperature increases. Conversely, the filter’s pressure drop decreases by increasing the gas temperature.

  3. Characteristics of Electret Non-woven Materials Applied to Air Filtration%驻极体非织造材料在空气过滤方面的应用特点

    Institute of Scientific and Technical Information of China (English)

    武松梅; 袁传刚

    2012-01-01

    The electret mechanism of air filtration material was briefly introduced. The characteris- tics of electret air filtration materials were elaborated in detail.%文章简要介紹了驻极体空气过滤材料的驻极机理,重点阐述了驻极体空气过滤材料的特点。

  4. Measured performance of filtration and ventilation systems for fine and ultrafine particles and ozone in an unoccupied modern California house.

    Science.gov (United States)

    Singer, B C; Delp, W W; Black, D R; Walker, I S

    2016-12-05

    This study evaluated nine ventilation and filtration systems in an unoccupied 2006 house located 250 m downwind of the I-80 freeway in Sacramento, California. Systems were evaluated for reducing indoor concentrations of outdoor particles in summer and fall/winter, ozone in summer, and particles from stir-fry cooking. Air exchange rate was measured continuously. Energy use was estimated for year-round operation in California. Exhaust ventilation without enhanced filtration provided indoor PM2.5 that was 70% lower than outdoors. Supply ventilation with MERV13 filtration provided slightly less protection, whereas supply MERV16 filtration reduced PM2.5 by 97-98% relative to outdoors. Supply filtration systems used little energy but provided no benefits for indoor-generated particles. Systems with MERV13-16 filter in the recirculating heating and cooling unit (FAU) operating continuously or 20 min/h reduced PM2.5 by 93-98%. Across all systems, removal percentages were higher for ultrafine particles and lower for black carbon, relative to PM2.5 . Indoor ozone was 3-4% of outdoors for all systems except an electronic air cleaner that produced ozone. Filtration via the FAU or portable filtration units lowered PM2.5 by 25-75% when operated over the hour following cooking. The energy for year-round operation of FAU filtration with an efficient blower motor was estimated at 600 kWh/year.

  5. 40 CFR 1065.127 - Exhaust gas recirculation.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Exhaust gas recirculation. 1065.127 Section 1065.127 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.127 Exhaust gas recirculation. Use...

  6. Filtration Fundamentals.

    Science.gov (United States)

    Ward, Ken; Hunsaker, Scot

    1997-01-01

    Examines how choice of commercial swimming-pool filtration systems is driven by the project-specific needs of the pools. Also highlighted are definitions of specific terms used when discussing filtration systems. Questions that pool designers can answer to make filtration-system purchasing decisions are listed. (GR)

  7. Effect of Water Cleaning on Performance of Air Filtration Medias%水清洗对空气净化材料过滤性能的影响

    Institute of Scientific and Technical Information of China (English)

    刘晓培; 卞思思; 常德强; 毛宁; 柳静献; 孙熙

    2012-01-01

    Air filtration media are designed for disposable, but in some application, it should be used for many times with water cleaning. Through experiments, the performances of polyester fiber layer media, which are cleaned with water for many times, including filtration elfieieney, resistance, dust capacity are studied in the paper. It was indicated by the results that water cleaning has less effect on filtration et/ieieney, resistance and dust capacity of the filter media. Therefore, air filtration media can be used repeatedly by way of water cleaning.%用于空气净化的材料一般为一次性使用,但有的应用场所需要对其进行反复水清洗多次使用。通过实验手段,研究常规涤纶纤维层滤料,在荷尘、清洗、烘干、荷尘等多次反复中其过滤效率、阻力、容尘量的变化情况。实验结果表明,清洗对滤料的过滤效率、阻力和容尘量没有明显的影响,滤料可以通过水清洗的方式反复使用。

  8. Environmental control implications of generating electric power from coal. 1977 technology status report. Appendix D. Assessment of NO/sub x/ control technology for coal fired utility boilers. [Low-excess-air, staged combustion, flu gas recirculation and burner design

    Energy Technology Data Exchange (ETDEWEB)

    1977-12-01

    An NOx control technology assessment study was conducted to examine the effectiveness of low-excess-air firing, staged combustion, flue gas recirculation, and current burner/boiler designs as applied to coal-fired utility boilers. Significant variations in NOx emissions exist with boiler type, firing method, and coal type, but a relative comparison of emissions control performance, cost, and operational considerations is presented for each method. The study emphasized the numerous operational factors that are of major importance to the user in selecting and implementing a combustion modification technique. Staged combustion and low-excess-air operation were identified as the most cost-effective methods for existing units. Close control of local air/fuel ratios and rigorous combustion equipment maintenance are essential to the success of both methods. Flue gas recirculation is relatively ineffective and has the added concern of tube erosion. More research is needed to resolve potential corrosion concerns with low-NOx operating modes. Low-NOx burners in conjunction with a compartmentalized windbox are capable of meeting a 0.6-lb/million Btu emission level on new units. Advanced burner designs are being developed to meet research emission goals of approximately 0.25 lb/MBtu.

  9. 家用空调过滤网过滤效果分析%Filtration Efficiency Analysis of Household Air Condition’s Filter

    Institute of Scientific and Technical Information of China (English)

    曲洁琼; 强天伟; 任永花

    2016-01-01

    本文通过对家用空调过滤网清洗前和清洗后两种状态下的过滤情况进行测试,分别分析其过滤效率与粒径、风速之间的关系,以及风速与阻力之间的关系,了解家用空调对于室内空气的过滤效果,以及清洗前和清洗后的家用空调过滤网对室内空气过滤效果的差异。%This paper tests two kinds of household air conditions’ filters, dirty and clean, analysing the relationship among filtration efficiency, particle size and wind speed, and the relationship between wind speed and resistance, knowing the filtration efficiency of household air condition to indoor air quality, and the different of filtration efficiency between the dirty and clean filters, then gives some corresponding conclusions.

  10. Beam Injection in Recirculator SALO

    CERN Document Server

    Guk, Ivan S; Dovbnya, Anatoly N; Kononenko, Stanislav; Peev, Fedor; Tarasenko, Alexander; Van der Wiel, Marnix

    2005-01-01

    Possible antetypes of injectors for electron recirculator SALO,* intended for nuclear-physical research, are analyzed. The plan injection of beams in recirculator is offered. Expected parameters of beams are designed.

  11. Engine with pulse-suppressed dedicated exhaust gas recirculation

    Science.gov (United States)

    Keating, Edward J.; Baker, Rodney E.

    2016-06-07

    An engine assembly includes an intake assembly, a spark-ignited internal combustion engine, and an exhaust assembly. The intake assembly includes a charge air cooler disposed between an exhaust gas recirculation (EGR) mixer and a backpressure valve. The charge air cooler has both an inlet and an outlet, and the back pressure valve is configured to maintain a minimum pressure difference between the inlet of the charge air cooler and an outlet of the backpressure valve. A dedicated exhaust gas recirculation system is provided in fluid communication with at least one cylinder and with the EGR mixer. The dedicated exhaust gas recirculation system is configured to route all of the exhaust gas from the at least one cylinder to the EGR mixer for recirculation back to the engine.

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

    Science.gov (United States)

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

    2011-09-01

    We grew multi-walled carbon nanotubes (MWCNTs) on a glass fiber air filter using thermal chemical vapor deposition (CVD) after the filter was catalytically activated with a spark discharge. After the CNT deposition, filtration and antibacterial tests were performed with the filters. Potassium chloride (KCl) particles (pressure drop across the filter. When a pristine glass fiber filter that had no CNTs was used, the particle filtration efficiencies at particle sizes under 30 nm and near 500 nm were 48.5% and 46.8%, respectively. However, the efficiencies increased to 64.3% and 60.2%, respectively, when the CNT-deposited filter was used. The reduction in the number of viable cells was determined by counting the colony forming units (CFU) of each test filter after contact with the cells. The pristine glass fiber filter was used as a control, and 83.7% of the E. coli were inactivated on the CNT-deposited filter.

  13. 再循环自净型排风柜面风速范围的最优化研究%Numerical simulation for optimum face velocity range of recirculation filtration fume hood

    Institute of Scientific and Technical Information of China (English)

    程勇; 刘东; 李斯玮; 王新林

    2011-01-01

    采用数值模拟方法,分析了面风速、操作面设计形式,假人高度和位置对再循环自净型排风柜性能的影响.结果显示,面风速为0.4~0.7 m/s,操作面采用拉门设计,假人站立于操作面中央操作时,排风柜内、外的气流组织形式和对柜内化学物的控制效果较好.结合实测数据分析了面风速对过滤器吸附速度的影响.%Investigates the influence of face velocity, design of the operation panel, height and position of anthropomorphic dummy on the performance of the hood through numerical simulation.The results show that for the face velocity from 0.4 m/s to 0.7 m/s, using sliding sash, and the dummy standing in the middle of the hood for operation, the air distribution inside and outside of the hood and contaminant control effect will be better.Analyses the effect of the face velocity on adsorption velocity of the filter with tested data.

  14. A Randomized Cross-over Air Filtration Intervention Trial for Reducing Cardiovascular Health Risks in Residents of Public Housing near a Highway

    Directory of Open Access Journals (Sweden)

    Luz T. Padró-Martínez

    2015-07-01

    Full Text Available Exposure to traffic-generated ultrafine particles (UFP; particles <100 nm is likely a risk factor for cardiovascular disease. We conducted a trial of high-efficiency particulate arrestance (HEPA filtration in public housing near a highway. Twenty residents in 19 apartments living <200 m from the highway participated in a randomized, double-blind crossover trial. A HEPA filter unit and a particle counter (measuring particle number concentration (PNC, a proxy for UFP were installed in living rooms. Participants were exposed to filtered air for 21 days and unfiltered air for 21 days. Blood samples were collected and blood pressure measured at days 0, 21 and 42 after a 12-hour fasting period. Plasma was analyzed for high sensitivity C-reactive protein (hsCRP, interleukin-6 (IL-6, tumor necrosis factor alpha-receptor II (TNF-RII and fibrinogen. PNC reductions ranging from 21% to 68% were recorded in 15 of the apartments. We observed no significant differences in blood pressure or three of the four biomarkers (hsCRP, fibrinogen, and TNF-RII measured in participants after 21-day exposure to HEPA-filtered air compared to measurements after 21-day exposure to sham-filtered air. In contrast, IL-6 concentrations were significantly higher following HEPA filtration (0.668 pg/mL; CI = 0.465–0.959 compared to sham filtration. Likewise, PNC adjusted for time activity were associated with increasing IL-6 in 14- and 21-day moving averages, and PNC was associated with decreasing blood pressure in Lags 0, 1 and 2, and in a 3-day moving average. These negative associations were unexpected and could be due to a combination of factors including exposure misclassification, unsuccessful randomization (i.e., IL-6 and use of anti-inflammatory medicines, or uncontrolled confounding. Studies with greater reduction in UFP levels and larger sample sizes are needed. There also needs to be more complete assessment of resident time activity and of outdoor vs. indoor source

  15. Shortening filtrations

    Institute of Scientific and Technical Information of China (English)

    ENOCHS Edgar E.

    2012-01-01

    Let C be a set of modules.We argue that there is an ordinal κ such that if a module has a filtration by modules in C,then it has a filtration of length κ by direct sums of modules in C.As an application we give another way to prove a result of Saorín and (S)(t)oví(c)ek and of (S)(t)oví(c)ek.

  16. Succession of microorganisms in a plate-type air treatment biofilter during filtration of various volatile compounds.

    Science.gov (United States)

    Repečkienė, Jūratė; Švedienė, Jurgita; Paškevičius, Algimantas; Tekorienė, Rūta; Raudonienė, Vita; Gudeliūnaitė, Eglė; Baltrėnas, Pranas; Misevičius, Antonas

    2015-01-01

    Changes in the number and species diversity of cultivable microorganisms in a newly developed plate-type biofilter during filtration of various volatile pollutants were studied. The novelty of the investigation is the monitoring of microorganism succession in different parts of biofilter plates with original packing material consisting of birch fibre and needle-punched non-woven fabric. It was shown that the largest number of fungi and yeasts develop on the top and middle, while bacteria develop on the bottom and middle parts of plates. The number of microorganisms depends on the origin of the pollutant, the pH and temperature inside the biofilter and the moisture of the porous plates. The statistically significant correlation between the number of microorganisms and inlet concentration of acetone was estimated, while ammonia showed a negative influence on yeast distribution. Paecilomyces variotii, Rhodotorula mucilaginosa and Bacillus subtilis were the most common organisms found during filtration of all examined volatiles; however, some differences of microbial communities in different parts of the biofilter plates and filtrated volatile compounds were obtained.

  17. Measured performance of filtration and ventilation systems for fine and ultrafine particles and ozone in an unoccupied modern California house

    Energy Technology Data Exchange (ETDEWEB)

    Singer, Brett C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Delp, William W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Black, Douglas R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-12-01

    This study evaluated nine ventilation and filtration systems in an unoccupied 2006 house located 250m downwind of the I-80 freeway in Sacramento, California. Systems were evaluated for reducing indoor concentrations of outdoor particles in summer and fall/winter, ozone in summer, and particles from stir-fry cooking. Air exchange rate was measured continuously. Energy use was estimated for year-round operation in California. Exhaust ventilation without enhanced filtration produced indoor PM2.5 that was 70% lower than outdoors. Supply ventilation with MERV13 filtration provided slightly less protection whereas supply MERV16 filtration reduced PM2.55 by 97-98% relative to outdoors. Supply filtration systems used little energy but provided no benefits for indoor-generated particles. Systems with MERV13-16 filters in the recirculating heating and cooling unit (FAU) operating continuously or 20 min/h reduced PM2.5 by 93-98%. Across all systems, removal percentages were higher for ultrafine particles and lower for black carbon, relative to PM2.5. Indoor ozone was 3-4% of outdoors for all systems except an electronic air cleaner that produced ozone. Filtration via the FAU or portable filtration units lowered PM2.5 by 25-75% when operated over the hour following cooking. The energy for year-round operation of FAU filtration with an efficient blower motor was estimated at 600 kWh/year.

  18. Removal of benzene and toluene from a refinery waste air stream by water sorption and biotrickling filtration

    OpenAIRE

    Paolo Viotti; Marco Schiavon; Renato Gavasci; Capodaglio,Andrea G.

    2015-01-01

    The paper presents the results of an analysis of a two-stage pilot plant for the removal of toluene and benzene from the exhaust air of an industrial wastewater treatment plant (WWTP). The two-stage air process combines a water scrubber and a biotrickling filter (BTF) in sequence, and treats air stripped from the liquid phase compartments of the WWTP. During the experimental period, the pilot plant treated an airflow of 600 Nm3h-1. Average concentrations of the waste air stream entering the w...

  19. Technology Solutions Case Study: Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    Energy Technology Data Exchange (ETDEWEB)

    A. Rudd and D. Bergey

    2015-08-01

    Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs.

  20. Building America Case Study: Ventilation System Effectiveness and Tested Indoor Air Quality Impacts, Tyler, Texas

    Energy Technology Data Exchange (ETDEWEB)

    2015-08-01

    ?Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four System Factor Categories: Balance, Distribution, Outside Air Source, and Recirculation Filtration. Recommended System Factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy.

  1. Filter System Performance in a Tilapia Recirculating System

    Directory of Open Access Journals (Sweden)

    Cristian Savin

    2012-10-01

    Full Text Available It is known that recirculating aquaculture systems, although has some advantages, production costs resulting from these production systems are quite high and is mainly due to the filtration system of technological water. Tilapia is one of the most important species in world aquaculture, the second production after carp, because of the advantages it has being reared in any production system: ponds, net-pens, cages, raceways, recirculating systems. Aim of this study was to evaluate the performance of a filter system in a tilapia recirculating system. Experiments were conducted during October – December 2011, during which feeding was done only with feed, Nutra category, ageappropriate granulation. Main physical – chemical parameters of technological water were monitored, pH, dissolved oxygen, nitrite, ammonia and ammonium, both the water entry in the filter and the exit from the filter. Filtration efficiency varied from 2-3% and up to 50-60%, mainly due to rapid loading of the filter and its need for cleaning.

  2. Preoperational test report, recirculation ventilation systems

    Energy Technology Data Exchange (ETDEWEB)

    Clifton, F.T.

    1997-11-11

    This represents a preoperational test report for Recirculation Ventilation Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102 and supports the ability to exhaust air from each tank. Each system consists of a valved piping loop, a fan, condenser, and moisture separator; equipment is located inside each respective tank farm in its own hardened building. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  3. Health benefits of particle filtration.

    Science.gov (United States)

    Fisk, W J

    2013-10-01

    The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also, reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and asthma health effects; however, many early studies had weak designs. A majority of recent intervention studies employed strong designs and more of these studies report statistically significant improvements in health symptoms or objective health outcomes, particularly for subjects with allergies or asthma. The percentage improvement in health outcomes is typically modest, for example, 7% to 25%. Delivery of filtered air to the breathing zone of sleeping allergic or asthmatic persons may be more consistently effective in improving health than room air filtration. Notable are two studies that report statistically significant improvements, with filtration, in markers that predict future adverse coronary events. From modeling, the largest potential benefits of indoor particle filtration may be reductions in morbidity and mortality from reducing indoor exposures to particles from outdoor air.

  4. Health Benefits of Particle Filtration

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, William J.

    2013-10-01

    The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and asthma health effects; however, many early studies had weak designs. A majority of recent intervention studies employed strong designs and more of these studies report statistically significant improvements in health symptoms or objective health outcomes, particularly for subjects with allergies or asthma. The percentage improvement in health outcomes is typically modest, e.g., 7percent to 25percent. Delivery of filtered air to the breathing zone of sleeping allergic or asthmatic persons may be more consistently effective in improving health than room air filtration. Notable are two studies that report statistically significant improvements, with filtration, in markers that predict future adverse coronary events. From modeling, the largest potential benefits of indoor particle filtration may be reductions in morbidity and mortality from reducing indoor exposures to particles from outdoor air.

  5. Health Benefits of Particle Filtration

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, William J.

    2013-10-01

    The evidence of health benefits of particle filtration in homes and commercial buildings is reviewed. Prior reviews of papers published before 2000 are summarized. The results of 16 more recent intervention studies are compiled and analyzed. Also, reviewed are four studies that modeled health benefits of using filtration to reduce indoor exposures to particles from outdoors. Prior reviews generally concluded that particle filtration is, at best, a source of small improvements in allergy and asthma health effects; however, many early studies had weak designs. A majority of recent intervention studies employed strong designs and more of these studies report statistically significant improvements in health symptoms or objective health outcomes, particularly for subjects with allergies or asthma. The percent age improvement in health outcomes is typically modest, for example, 7percent to 25percent. Delivery of filtered air to the breathing zone of sleeping allergic or asthmatic persons may be more consistently effective in improving health than room air filtration. Notable are two studies that report statistically significant improvements, with filtration, in markers that predict future adverse coronary events. From modeling, the largest potential benefits of indoor particle filtration may be reductions in morbidity and mortality from reducing indoor exposures to particles from outdoor air.

  6. Removal of benzene and toluene from a refinery waste air stream by water sorption and biotrickling filtration

    Directory of Open Access Journals (Sweden)

    Paolo Viotti

    2015-11-01

    Full Text Available The paper presents the results of an analysis of a two-stage pilot plant for the removal of toluene and benzene from the exhaust air of an industrial wastewater treatment plant (WWTP. The two-stage air process combines a water scrubber and a biotrickling filter (BTF in sequence, and treats air stripped from the liquid phase compartments of the WWTP. During the experimental period, the pilot plant treated an airflow of 600 Nm3h-1. Average concentrations of the waste air stream entering the water scrubber were 10.61 mg Nm-3 benzene and 9.26 mg Nm-3 toluene. The water scrubber obtained medium-high removal efficiencies (averages 51% and 60%, for benzene and toluene, respectively. Subsequent passage through the BTF allowed a further reduction of average concentrations, which decreased to 2.10 mg Nm-3 benzene and to 0.84 mg Nm-3 toluene, thereby allowing overall average removal efficiencies (REs of 80% and 91% for benzene and toluene, respectively. Results prove the benefits obtained from a combination of different removal technologies: water scrubbers to remove peak concentrations and soluble compounds, and BTFs to remove compounds with lower solubility, due to the biodegradation performed by microorganisms.

  7. Latest aspects of mechanical filtration

    Directory of Open Access Journals (Sweden)

    Stanislav Koláček

    2013-01-01

    Full Text Available The aim of this study was to describe and unify all knowledge about mechanic filtration. The first part deals with the parameters and properties of filtration. Here some important basic concepts are explained such as pressure gradient, filter life, etc. There’s also a description of convenient filtration technology for coarse and fine materials, such as sand, smoke or soot. The second part primarily focuses on the real use and application of filters for liquid and gaseous media. The differences in construction between different types of filters for filtration of fuels, oils, hydraulic fluids, air and cabin filters are described. The last section is focused mainly on new materials for the production of filters. These materials are ceramic or nanomaterials, which can actually be enriched for example with antibacterial silver or some fungicides.

  8. Treatment of refractory nano-filtration reject from a tannery using Pd-catalyzed wet air oxidation.

    Science.gov (United States)

    Tripathi, Pranav K; Rao, Nageswara N; Chauhan, Chetan; Pophali, Girish R; Kashyap, Sanjay M; Lokhande, Satish K; Gan, Lihua

    2013-10-15

    We attempted catalytic wet air oxidation (CWAO) of nanofiltration (NF)-reject using Pd based catalyst viz., Pd/activated charcoal (AC) and PdCl2 with the objective of degradation of refractory organic pollutants. Refractory organic pollutants in NF-reject before and after WAO and CWAO were confirmed by GC-MS analysis. Experiments were conducted to investigate the effects of temperature, catalyst dosage and air partial pressure on the rate of removal of total organic carbon (TOC). The reaction kinetics can be conveniently described by considering two-stage first order kinetics. The use of Pd/AC afforded 85% TOC removal, the corresponding rate constant (k) was 2.90 ± 0.075 × 10(-3)min(-1) (Pd/AC, 100mg/L; T, 473.15K; Pair, 0.69 MPa). On the other hand, 75% TOC was removed with k=2.31 ± 0.075 × 10(-3)min(-1) using Pd(2+) catalyst (Pd(2+), 16.66 mg/L; T, 473.15K; Pair, 0.69 MPa). The observed rate of mineralization under Pd-catalyzed conditions was significantly higher than that of the uncatalyzed oxidation (41%) under the similar experimental conditions. Catalyst stability experiments were performed and TEM, SEM, XRD, Raman and XPS characterization data collected. Despite some morphological transformation of support, Pd catalyst was stable under CWAO conditions.

  9. Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    Energy Technology Data Exchange (ETDEWEB)

    Rudd, A.; Bergey, D.

    2014-02-01

    Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy. It was inferior because the source of outside air was not direct from outside, the ventilation air was not distributed, and no provision existed for air filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four System Factor Categories: Balance, Distribution, Outside Air Source, and Recirculation Filtration. Recommended System Factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year.

  10. Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    Energy Technology Data Exchange (ETDEWEB)

    Rudd, Armin [Building Science Corporation, Somerville, MA (United States); Bergey, Daniel [Building Science Corporation, Somerville, MA (United States)

    2014-02-01

    In this project, Building America research team Building Science Corporation tested the effectiveness of ventilation systems at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy. This was because the source of outside air was not direct from outside, the ventilation air was not distributed, and no provision existed for air filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four system factor categories: balance, distribution, outside air source, and recirculation filtration. Recommended system factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year.

  11. 驻极处理对熔喷空气过滤材料过滤性能的影响%The influence on filtration efficiency of melt-blown air filter material after electrets treatment

    Institute of Scientific and Technical Information of China (English)

    刘超

    2013-01-01

      The structure characteristic and filtration mechanism of melt-blown filtration materials were introduced. The influence of melt-blown filtration material with electrets treatment on the filtration efficiency was studied.The electrets treatment could enhance filtration efficiency of the material greatly and almost re-main absorption resistance stable , the filtration efficiency of the material would increase by rise of elec-trets voltage.The filtration efficiency of melt-blown filtration material with electrets treatment was high-er than that of the melt-blown filtration material spray nanofiber and the absorption resistance of the melt-blown filtration material spray nanofiber was higher than the national standard and larger than that of the former.The electrets treatment was an important process on melt-blown air filter material and could be applied on production widely .%  介绍了熔喷过滤材料的结构特点和过滤机理,研究了驻极处理对熔喷过滤材料过滤性能的影响。结果表明:驻极处理能够大幅度地提高熔喷空气过滤材料的过滤效率而保持呼吸阻力几乎不变,并随着驻极电压的增加,过滤效率增大;在熔喷空气过滤材料上喷涂纳米纤维后,其过滤效率低于经驻极处理的熔喷空气过滤材料,而呼吸阻力却急剧增大,远远超过国家标准(≤350 Pa)的要求。驻极处理方法是熔喷空气过滤材料重要的一种处理工艺,可在生产中广泛应用。

  12. Microscreen effects on water quality in replicated recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Fernandes, Paulo; Pedersen, Lars-Flemming; Pedersen, Per Bovbjerg

    2015-01-01

    This study investigated the effects of three microscreen mesh sizes (100, 60 and 20 μm) on water quality and rainbow trout (Oncorhynchus mykiss) performance compared to a control group without microscreens, in triplicated recirculating aquaculture systems (RAS). Operational conditions were kept....... Fish performed similarly in all treatments. Preliminary screening of trout gills did not reveal any pathological changes related to microscreen filtration and the resulting water quality. Biofilter performance was also unaffected, with 0′-order nitrification rates (k0a) being equivalent for all twelve...

  13. Reducing Mortality from Terrorist Releases of Chemical and Biological Agents: I. Filtration for Ventilation Systems in Commercial Building

    Energy Technology Data Exchange (ETDEWEB)

    Thatcher, Tracy L.; Daisey, Joan M.

    1999-09-01

    There is growing concern about potential terrorist attacks involving releases of chemical and/or biological (CB) agents, such as sarin or anthrax, in and around buildings. For an external release, the CB agent can enter the building through the air intakes of a building's mechanical ventilation system and by infiltration through the building envelope. For an interior release in a single room, the mechanical ventilation system, which often recirculates some fraction of the air within a building, may distribute the released CB agent throughout the building. For both cases, installing building systems that remove chemical and biological agents may be the most effective way to protect building occupants. Filtration systems installed in the heating, ventilating and air-conditioning (HVAC) systems of buildings can significantly reduce exposures of building occupants in the event of a release, whether the release is outdoors or indoors. Reduced exposures can reduce the number of deaths from a terrorist attack. The purpose of this report is to provide information and examples of the design of filtration systems to help building engineers retrofit HVAC systems. The report also provides background information on the physical nature of CB agents and brief overviews of the basic principles of particle and vapor filtration.

  14. The impact of tropical recirculation on polar composition

    Directory of Open Access Journals (Sweden)

    S. E. Strahan

    2009-01-01

    Full Text Available We derive the tropical modal age of air from an analysis of the water vapor tape recorder. We combine the observationally derived modal age with mean age of air from CO2 and SF6 to create diagnostics for the independent evaluation of the vertical transport rate and horizontal recirculation into the tropics between 16–32 km. These diagnostics are applied to two Global Modeling Initiative (GMI chemistry and transport model (CTM age tracer simulations to give new insights into the tropical transport characteristics of the meteorological fields from the GEOS4-GCM and the GEOS4-DAS. Both simulations are found to have modal ages that are in reasonable agreement with the empirically derived age (i.e., transit times over the entire altitude range. Both simulations show too little horizontal recirculation into the tropics above 22 km, with the GEOS4-DAS fields having greater recirculation. Using CH4 as a proxy for mean age, comparisons between HALOE and model CH4 in the Antarctic demonstrate how the strength of tropical recirculation affects polar composition in both CTM experiments. The better the tropical recirculation is simulated, the better the CH4 simulation is in the Antarctic. Mean age in the Antarctic lower stratosphere can be compromised by poor representation of tropical ascent, tropical recirculation, or vortex barrier strength. The connection between polar and tropical composition shown in this study demonstrates the importance of diagnosing each of these processes separately in order to verify the adequate representation of the processes contributing to polar composition in models.

  15. The impact of tropical recirculation on polar composition

    Directory of Open Access Journals (Sweden)

    S. E. Strahan

    2009-04-01

    Full Text Available We derive the tropical modal age of air from an analysis of the water vapor tape recorder. We combine the observationally derived modal age with mean age of air from CO2 and SF6 to create diagnostics for the independent evaluation of the vertical transport rate and horizontal recirculation into the tropics between 16–32 km. These diagnostics are applied to two Global Modeling Initiative (GMI chemistry and transport model (CTM age tracer simulations to give new insights into the tropical transport characteristics of the meteorological fields from the GEOS4-GCM and the GEOS4-DAS. Both simulations are found to have modal ages that are in reasonable agreement with the empirically derived age (i.e., transit times over the entire altitude range. Both simulations show too little horizontal recirculation into the tropics above 22 km, with the GEOS4-DAS fields having greater recirculation. Using CH4 as a proxy for mean age, comparisons between HALOE and model CH4 in the Antarctic demonstrate how the strength of tropical recirculation affects polar composition in both CTM experiments. Better tropical recirculation tends to improve the CH4 simulation in the Antarctic. However, mean age in the Antarctic lower stratosphere can be compromised by poor representation of tropical ascent, tropical recirculation, or vortex barrier strength. The connection between polar and tropical composition shown in this study demonstrates the importance of diagnosing each of these processes separately in order to verify the adequate representation of the processes contributing to polar composition in models.

  16. 过滤室内空气对降低居民室内氡照射的效果研究%The study on effects of indoor air filtration on radon exposure to residents

    Institute of Scientific and Technical Information of China (English)

    贺丽萍; 陈波; 赵超; 卓维海

    2016-01-01

    Objective To evaluate the influence of indoor air filtration by air purifier on the behavior of indoor radon progeny and estimate its effects on indoor radon exposure to residents.Methods The concentrations of indoor radon progeny with and without the air filtration were calculated by the theoretical model developed in this study.Based on the dose conversion factors of attached and unattached radon progeny,the mitigation effects of indoor radon exposure due to the air filtration were estimated.Verification experiments were conducted in an airtight room.Results With the air filtration rate increased,the removal efficiency of indoor radon progeny would appear more obvious.For an airtight room with its initial aerosol concentration of 10 000 cm-3,the concentration of total radon progeny would decrease by more than 90% when the air filtration rate exceeded 10 h-1.But the concentrations of indoor unattached radon progeny would increase by using the air purifier in different extents.The variations of radon progeny concentrations and the decrease of internal doses were closely related to the filtration rate of air purifier.With the air filtration rates increased,the mitigation effects would be better and faster.The internal dose would reduce by more than 70% when the filtration rate exceeded 5 h-1.Conclusions Although the indoor concentration of unattached radon progeny will increase by using the air purifier,it is still effective in reducing the exposure dose to residents due to the inhalation of radon progeny.%目的 研究空气净化器过滤室内空气对室内氡子体行为的影响,探讨该方法对降低居民室内氡照射的效果.方法 构建理论模型计算室内空气过滤前后室内氡子体的浓度,基于结合态和未结合态氡子体的剂量转换系数,评估过滤室内空气对居民氡照射剂量的降低效果,并在密闭房间内进行部分实验验证.结果 室内空气的过滤速率越大,氡子体的去除效率越明显.

  17. Technology Review of Modern Gas Turbine Inlet Filtration Systems

    OpenAIRE

    2012-01-01

    An inlet air filtration system is essential for the successful operation of a gas turbine. The filtration system protects the gas turbine from harmful debris in the ambient air, which can lead to issues such as FOD, erosion, fouling, and corrosion. These issues if not addressed will result in a shorter operational life and reduced performance of the gas turbine. Modern day filtration systems are comprised of multiple filtration stages. Each stage is selected based on the local operating envir...

  18. Recirculation nursery systems for bivalves

    NARCIS (Netherlands)

    Kamermans, P.; Blanco Garcia, A.; Joaquim, Sandra; Matias, Domitilia; Magnesen, Thorolf; Nicolas, J.; Petten, Bruno; Robert, Rene

    2016-01-01

    n order to increase production of bivalves in hatcheries and nurseries, the development of new technology and its integration into commercial bivalve hatcheries is important. Recirculation aquaculture systems (RASs) have several advantages: high densities of the species can be cultured resulting in

  19. Aerosol Filtration Application Using Fibrous Media An Industrial Perspective

    Institute of Scientific and Technical Information of China (English)

    杨传芳

    2012-01-01

    Filtration of aerosol particles using non-woven fibrous media is a common practice for air cleaning. It has found wide applications in industries and our daily lives. This paper overviews some of these applications and provides an industrial perspective. It starts from discussing aerosol filtration theory, followed by a brief review on the advancement of filtration media. After that, filtration applications in respiratory protection, dust collection, and engine in-take air cleaning are elaborated. These are the areas that the author sees as the typical needed ones in China's fast pace economical development endeavor, where air filtration enables the protection of human health, environment and equipment for sustainability.

  20. The Applications of Electret Air Filtration Material in Breath Protection Products%驻极体空气过滤材料在呼吸防护用品中的应用

    Institute of Scientific and Technical Information of China (English)

    陈钢进; 肖慧明; 王良基

    2011-01-01

    This paper introduce briefly the applications and preparation of electret air filtration material in breath protection products as well as the characteristics of anti bacterium, clean-resistant, solvent- resistant and stability. At the same time, electret air filtration material which is a kind of promising new breath protection products material are also explained.%本文主要介绍了驻极体空气过滤材料在呼吸防护用品中的应用、制备以及抗菌性能、耐清洗性能、耐溶剂性能、稳定性等性能特性,并说明驻极体空气过滤材料是一类非常有应用前景的呼吸防护用品材料。

  1. Sulphur recirculation for reduced boiler corrosion; Minskad pannkorrosion med svavelrecirkulation

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Sven; Karlsson, Martin (Goetaverken Miljoe AB, Goeteborg (Sweden)); Blomqvist, Evalena; Baefver, Linda; Claesson, Frida; Davidsson, Kent (SP Sveriges Tekniska Forskningsinstitut, Boraas (Sweden)); Froitzheim, Jan; Pettersson, Jesper; Steenari, Britt-Marie (Chalmers Tekniska Hoegskola, Oorganisk miljoekemi, Goeteborg (Sweden))

    2010-03-15

    Sulphur recirculation is a new technology for reducing boiler corrosion and dioxin formation, which was demonstrated in full-scale tests performed at the Renova Waste to Energy plant at Saevenaes in Goeteborg (Sweden). Sulphur is recirculated from the flue gas cleaning back to the boiler, which reduces the chloride content of the deposits, which in turn reduces boiler corrosion and dioxin formation. Sulphur dioxide was separated from the flue gas in a wet scrubber by adding hydrogen peroxide, producing sulphuric acid. The sulphuric acid was injected into the furnace using nozzles with atomization air, surrounded by recirculated flue gas for improved mixing. By recirculating the sulphur, the sulphur dioxide concentration was increased in the boiler. Each sulphur atom passed the boiler several times and no external sulphur had to be added. Dioxin, ash, deposits and particle samplings together with 1000 h corrosion probe measurements were performed for normal operation (reference) and with sulphur recirculation respectively. During spring 2009, reference measurements were made and the recirculation system was installed and tested. During autumn 2009, a long term test with sulphur recirculation was made. An SO{sub 2} concentration of approximately 800 mg/m3 (n, d.g.) was maintained in the boiler by the system except during a period of extremely low sulphur content in the waste. The sulphur dioxide stack concentrations have been far below the emission limit. Sulphuric acid dew point measurements have shown that the sulphuric acid dosage did not lead to elevated SO{sub 3} concentrations, which may otherwise lead to low temperature corrosion. The chlorine content of both fly ash and boiler ash decreased and the sulphur content increased during the sulphur recirculation tests. The molar chlorine/sulphur ratio (Cl/S) decreased by two thirds in the fly ash as well as in the boiler ash, except for one sample. With sulphur recirculation in operation, the deposit growth was

  2. Heating, ventilation and air conditioning system modelling

    Energy Technology Data Exchange (ETDEWEB)

    Whalley, R.; Abdul-Ameer, A. [British University in Dubai (United Arab Emirates)

    2011-03-15

    Heating, ventilation and air conditioning modelling methods, for large scale, spatially dispersed systems are considered. Existing techniques are discussed and proposals for the application of novel analysis approaches are outlined. The use of distributed-lumped parameter procedures enabling the incorporation of the relatively concentrated and significantly dispersed, system element characteristics, is advocated. A dynamic model for a heating, ventilation and air conditioning system comprising inlet and exhaust fans, with air recirculation, heating/cooling and filtration units is presented. Pressure, airflow and temperature predictions within the system are computed following input, disturbance changes and purging operations. The generalised modelling advancements adopted and the applicability of the model for heating, ventilation and air conditioning system simulation, re-configuration and diagnostics is emphasised. The employment of the model for automatic, multivariable controller design purposes is commented upon. (author)

  3. Recirculation bubbler for glass melter apparatus

    Science.gov (United States)

    Guerrero, Hector; Bickford, Dennis

    2007-06-05

    A gas bubbler device provides enhanced recirculation of molten glass within a glass melter apparatus. The bubbler device includes a tube member disposed within a pool of molten glass contained in the melter. The tube member includes a lower opening through which the molten glass enters and upper slots disposed close to (above or below) the upper surface of the pool of molten glass and from which the glass exits. A gas (air) line is disposed within the tube member and extends longitudinally thereof. A gas bubble distribution device, which is located adjacent to the lower end of the tube member and is connected to the lower end of the gas line, releases gas through openings therein so as to produce gas bubbles of a desired size in the molten glass and in a distributed pattern across the tube member.

  4. Recirculated and Energy Recovered Linacs

    Energy Technology Data Exchange (ETDEWEB)

    Geoffrey Krafft

    2003-05-01

    Linacs that are recirculated share many characteristics with ordinary linacs, including the ability to accelerate electron beams from an injector to high energy with relatively little (normalized) emittance growth and the ability to deliver ultrashort bunch duration pulses to users. When such linacs are energy recovered, the additional possibility of accelerating very high average beam current arises. Because this combination of beam properties is not possible from either a conventional linac, or from storage rings where emittance and pulse length are set by the equilibrium between radiation damping and quantum excitation of oscillations about the closed orbit, energy recovered linacs are being considered for an increasing variety of applications. These possibilities extend from high power free-electron lasers and recirculated linac light sources, to electron coolers for high energy colliders or actual electron-ion colliding- beam machines based on an energy recovered linac for the electrons.

  5. Recirculated and Energy Recovered Linacs

    CERN Document Server

    Geoffr-Ey-Kraff

    2003-01-01

    Linacs that are recirculated share many characteristics with ordinary linacs, including the ability to accelerate electron beams FR-om an injector to high energy with relatively little (normalized) emittance growth and the ability to deliver ultrashort bunch duration pulses to users. When such linacs are energy recovered, the additional possibility of accelerating very high average beam current arises. Because this combination of beam properties is not possible FR-om either a conventional linac, or FR-om storage rings where emittance and pulse length are set by the equilibrium between radiation damping and quantum excitation of oscillations about the closed orbit, energy recovered linacs are being considered for an increasing variety of applications. These possibilities extend FR-om high power FR-ee-electron lasers and recirculated linac light sources, to electron coolers for high energy colliders or actual electron-ion colliding- beam machines based on an energy recovered linac for the electrons.

  6. Glomerular filtration rate

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/007305.htm Glomerular filtration rate To use the sharing features on this page, please enable JavaScript. Glomerular filtration rate (GFR) is a test used to check ...

  7. Na+ recirculation and isosmotic transport.

    Science.gov (United States)

    Larsen, E H; Møbjerg, N

    2006-01-01

    The Na(+) recirculation theory for solute-coupled fluid absorption is an expansion of the local osmosis concept introduced by Curran and analyzed by Diamond & Bossert. Based on studies on small intestine the theory assumes that the observed recirculation of Na(+) serves regulation of the osmolarity of the absorbate. Mathematical modeling reproducing bioelectric and hydrosmotic properties of small intestine and proximal tubule, respectively, predicts a significant range of observations such as isosmotic transport, hyposmotic transport, solvent drag, anomalous solvent drag, the residual hydraulic permeability in proximal tubule of AQP1 (-/-) mice, and the inverse relationship between hydraulic permeability and the concentration difference needed to reverse transepithelial water flow. The model reproduces the volume responses of cells and lateral intercellular space (lis) following replacement of luminal NaCl by sucrose as well as the linear dependence of volume absorption on luminal NaCl concentration. Analysis of solvent drag on Na(+) in tight junctions provides explanation for the surprisingly high metabolic efficiency of Na(+) reabsorption. The model predicts and explains low metabolic efficiency in diluted external baths. Hyperosmolarity of lis is governed by the hydraulic permeability of the apical plasma membrane and tight junction with 6-7 mOsm in small intestine and < or = 1 mOsm in proximal tubule. Truly isosmotic transport demands a Na(+) recirculation of 50-70% in small intestine but might be barely measurable in proximal tubule. The model fails to reproduce a certain type of observations: The reduced volume absorption at transepithelial osmotic equilibrium in AQP1 knockout mice, and the stimulated water absorption by gallbladder in diluted external solutions. Thus, it indicates cellular regulation of apical Na(+) uptake, which is not included in the mathematical treatment.

  8. The impact of building recirculation rates on secondary organic aerosols generated by indoor chemistry

    DEFF Research Database (Denmark)

    Zuraimi, M.S.; Weschler, Charles J.; Tham, K.W.

    2007-01-01

    reactions between indoor limonene and ozone. The experiments were conducted in a large environmental chamber using four recirculation rates (11, 14, 19 and 24 air change per hour (ACH)) and a constant outdoor air exchange rate (I ACH) as well as constant emission rates for limonene and ozone...

  9. Rotary filtration system

    Science.gov (United States)

    Herman, David T.; Maxwell, David N.

    2011-04-19

    A rotary filtration apparatus for filtering a feed fluid into permeate is provided. The rotary filtration apparatus includes a container that has a feed fluid inlet. A shaft is at least partially disposed in the container and has a passageway for the transport of permeate. A disk stack made of a plurality of filtration disks is mounted onto the shaft so that rotation of the shaft causes rotation of the filtration disks. The filtration disks may be made of steel components and may be welded together. The shaft may penetrate a filtering section of the container at a single location. The rotary filtration apparatus may also incorporate a bellows seal to prevent leakage along the shaft, and an around the shaft union rotary joint to allow for removal of permeate. Various components of the rotary filtration apparatus may be removed as a single assembly.

  10. Spunlaced and chemically bonded nonwovens for filtration applications: Performance evaluation and comparison

    CSIR Research Space (South Africa)

    Boguslavsky, L

    2008-11-01

    Full Text Available The main function of textile filter media in air filtration is to control air pollution. Air filtration plays an important role in improving air quality and hygiene. The demands for air quality and hygiene at work places have increased greatly due...

  11. A Randomized Cross-over Air Filtration Intervention Trial for Reducing Cardiovascular Health Risks in Residents of Public Housing near a Highway

    National Research Council Canada - National Science Library

    Padró-Martínez, Luz T; Owusu, Emmanuel; Reisner, Ellen; Zamore, Wig; Simon, Matthew C; Mwamburi, Mkaya; Brown, Carrie A; Chung, Mei; Brugge, Doug; Durant, John L

    2015-01-01

    .... Participants were exposed to filtered air for 21 days and unfiltered air for 21 days. Blood samples were collected and blood pressure measured at days 0, 21 and 42 after a 12-hour fasting period...

  12. Hydroxyl time series and recirculation in turbulent nonpremixed swirling flames

    Energy Technology Data Exchange (ETDEWEB)

    Guttenfelder, Walter A.; Laurendeau, Normand M.; Ji, Jun; King, Galen B.; Gore, Jay P. [School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907-1288 (United States); Renfro, Michael W. [Department of Mechanical Engineering, University of Connecticut, Storrs, CT 06269-3139 (United States)

    2006-10-15

    Time-series measurements of OH, as related to accompanying flow structures, are reported using picosecond time-resolved laser-induced fluorescence (PITLIF) and particle-imaging velocimetry (PIV) for turbulent, swirling, nonpremixed methane-air flames. The [OH] data portray a primary reaction zone surrounding the internal recirculation zone, with residual OH in the recirculation zone approaching chemical equilibrium. Modeling of the OH electronic quenching environment, when compared to fluorescence lifetime measurements, offers additional evidence that the reaction zone burns as a partially premixed flame. A time-series analysis affirms the presence of thin flamelet-like regions based on the relation between swirl-induced turbulence and fluctuations of [OH] in the reaction and recirculation zones. The OH integral time-scales are found to correspond qualitatively to local mean velocities. Furthermore, quantitative dependencies can be established with respect to axial position, Reynolds number, and global equivalence ratio. Given these relationships, the OH time-scales, and thus the primary reaction zone, appear to be dominated by convection-driven fluctuations. Surprisingly, the OH time-scales for these nominally swirling flames demonstrate significant similarities to previous PITLIF results in nonpremixed jet flames. (author)

  13. A Study on the Adverse Effect of AOVs in AFWS Recirculation Paths on Plant Safety

    Energy Technology Data Exchange (ETDEWEB)

    Huong, Ho Thi Thanh [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Chung, Dae-Wook [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2014-10-15

    Auxiliary feedwater system (AFWS) recirculation flow paths adopted air operated valves (AOVs) which could fail close on loss of instrument air (LOIA) event. So the AOVs and recirculation paths are closed on LOIA event, which could result in Auxiliary feedwater (AFW) pump(s) damage, which contributes greatly to core damage frequency (CDF).. On February 2002, the USNRC issued an inspection finding related to potential common cause failure of AOVs in AFWS recirculation flow paths on loss of instrument air system in Point Beach nuclear power plant (Pt. Beach). The AOVs have been removed from AFWS recirculation paths in the design of Korea standard nuclear power plant (KSNP). So, there is no possibility of above mentioned failure event in KSNP. It would be beneficial to evaluate the significance of adverse effect of AOVs in AFWS recirculation paths to realize the importance of maintaining AFWS recirculation paths always open. In this study, the AFWS modeling of Ulchin unit 3 and 4 was modified to model the AOVs in AFW recirculation flow paths to evaluate the change in CDF, which is caused by the adverse effect of AOV with operation mode of 'fails close' on LOIA event. It is concluded that the existence of AOV with 'fail close' design in AFWS MDP recirculation paths results in CDF increase of 131%, which is significant adverse effect on plant safety.. In this regard, the improved Westinghouse design and KSNP design had removed the AOVs from AFWS MDP recirculation paths. However, a couple of units with old Westinghouse design, Kori 1 and 2, still have AOVs in AFWS MDP recirculation paths and throttle back operation of AFWS is in effect. Although those AOVs adopt 'fail open' design to prevent above mentioned inadvertent closure, considering the big increase in CDF, there still exists considerable risk from the possibility of 'failure to open' during this throttle back operation. Therefore, it is strongly recommended that any

  14. TANK MIXING STUDY WITH FLOW RECIRCULATION

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.

    2014-06-25

    The primary objective of this work is to quantify the mixing time when two miscible fluids are mixed by one recirculation pump and to evaluate adequacy of 2.5 hours of pump recirculation to be considered well mixed in SRS tanks, JT-71/72. The work scope described here consists of two modeling analyses. They are the steady state flow pattern analysis during pump recirculation operation of the tank liquid and transient species transport calculations based on the initial steady state flow patterns. The modeling calculations for the mixing time are performed by using the 99% homogeneity criterion for the entire domain of the tank contents.

  15. Biological flocculation treatment on distillery wastewater and recirculation of wastewater.

    Science.gov (United States)

    Zhang, Wen; Xiong, Rongchun; Wei, Gang

    2009-12-30

    In the present study, a wastewater treatment system for the ethanol fermentation industry was developed by recycling distillery wastewater. The waste was able to be recycled for the next fermentation after being treated with bio-flocculation process. The bio-flocculation process contains three steps: screening, treatment with polyaspartic acid and filtration. When the filtrate from this process was recycled, the average ethanol production yield was very close to that in the conventional process using tap water. In contrast, the recycle of wastewater without flocculation and with chemical flocculation showed negative effects on ethanol yield as recycling was repeated. This new process was confirmed to have stable operation over ten recycles. Hazardous materials influencing distillery wastewater recycles on fermentation were also considered. It was found that the content of suspended solids (SS), volatile acid and Fe ions inhibited fermentation and resulted in a decreased ethanol yield. Bio-flocculation was shown to be an effective way to diminish the content of inhibitory compounds drastically when the waste was recirculated.

  16. The study of recirculating aquaculture system in pond and its purification effect

    Science.gov (United States)

    Qu, Jiangqi; Zhang, Qingjing; Jia, Chengxia; Liu, Pan; Yang, Mu

    2017-05-01

    In this paper, a recirculating aquaculture purification system (RAPS) was designed to solve the problems of aquaculture pollution and shortage of freshwater resource according to the characteristic of northern freshwater ponds of China. The system were arranged in series and composed of high density culture pond, deposit pond, floating and submerged plant pond, ecological floating bed pond and biofilm filtrate pond. At the fish density of 20~30kg/m3 in the high density culture pond, the water quality parameters were monitored seasonally. The results indicated that the removal rate of total nitrogen, total phosphorus, ammonia nitrogen and nitrite nitrogen in the recirculating aquaculture system were 69.59%, 77.89%, 72.54% and 68.68%, respectively. The floating and submerged plant pond and ecological floating bed pond can remove TN and TP obviously, and increase dissolved oxygen and transparency significantly. And the biofilm filtrate pond has good effect of removing ammonium nitrogen and nitrite nitrogen, meanwhile, the microbial communities in the recirculating aquaculture system regulate on the water quality. Therefore, the RAPS show significant effects on water saving and pollution emission reducing.

  17. Magnetic-seeding filtration

    Energy Technology Data Exchange (ETDEWEB)

    Ying, T.Y.; Chin, C.J.; Lu, S.C.; Yiacoumi, S. [Georgia Institute of Technology, Atlanta, GA (United States). School of Civil and Environmental Engineering] [and others

    1997-10-01

    Magnetic-seeding filtration consists of two steps: heterogeneous particle flocculation of magnetic and nonmagnetic particles in a stirred tank and high-gradient magnetic filtration (HGMF). The effects of various parameters affecting magnetic-seeding filtration (HGMF). The effects of various parameters affecting magnetic seeding filtration are theoretically and experimentally investigated. A trajectory model that includes hydrodynamic resistance, van der Waals, and electrostatic forces is developed to calculate the flocculation frequency in a turbulent-shear regime. Fractal dimension is introduced to simulate the open structure of aggregates. A magnetic-filtration model that consists of trajectory analysis, a particle build-up model, a breakthrough model, and a bivariate population-balance model is developed to predict the breakthrough curve of magnetic-seeding filtration. A good agreement between modeling results and experimental data is obtained. The results show that the model developed in this study can be used to predict the performance of magnetic-seeding filtration without using empirical coefficients or fitting parameters. 35 refs., 7 figs., 1 tab.

  18. Thermal-hydraulic tests of a recirculation cooling installation for the Rostov nuclear power station

    Science.gov (United States)

    Balunov, B. F.; Balashov, V. A.; Il'in, V. A.; Krayushnikov, V. V.; Lychakov, V. D.; Meshalkin, V. V.; Ustinov, A. N.; Shcheglov, A. A.

    2013-09-01

    Results obtained from thermal-hydraulic tests of the recirculation cooling installation used as part of the air cooling system under the containments of the Rostov nuclear power station Units 3 and 4 are presented. The operating modes of the installation during normal operation (air cooling on the surface of finned tubes), under the conditions of anticipated operational occurrences (air cooling and steam condensation from a steam-air mixture), and during an accident (condensation of pure steam) are considered. Agreement is obtained between the results of tests and calculations carried out according to the recommendations given in the relevant regulatory documents. A procedure of carrying out thermal calculation for the case of steam condensation from a steam-air mixture on the surface of fins is proposed. The possibility of efficient use of the recirculation cooling installation in the system for reducing emergency pressure under the containment of a nuclear power station is demonstrated.

  19. Suction-recirculation device for stabilizing particle flows within a solar powered solid particle receiver

    Science.gov (United States)

    Kolb, Gregory J [Albuquerque, NM

    2012-02-07

    A suction-recirculation device for stabilizing the flow of a curtain of blackened heat absorption particles falling inside of a solar receiver with an open aperture. The curtain of particles absorbs the concentrated heat from a solar mirror array reflected up to the receiver on a solar power tower. External winds entering the receiver at an oblique angle can destabilize the particle curtain and eject particles. A fan and ductwork is located behind the back wall of the receiver and sucks air out through an array of small holes in the back wall. Any entrained particles are separated out by a conventional cyclone device. Then, the air is recirculated back to the top of the receiver by injecting the recycled air through an array of small holes in the receiver's ceiling and upper aperture front wall. Since internal air is recirculated, heat losses are minimized and high receiver efficiency is maintained. Suction-recirculation velocities in the range of 1-5 m/s are sufficient to stabilize the particle curtain against external wind speeds in excess of 10 m/s.

  20. Filtration in Porous Media

    DEFF Research Database (Denmark)

    Yuan, Hao; Shapiro, Alexander

    There is a considerable and ongoing effort aimed at understanding the transport and the deposition of suspended particles in porous media, especially non-Fickian transport and non-exponential deposition of particles. In this work, the influential parameters in filtration models are studied...... to understand their effects on the non-Fickian transport and the non-exponential deposition. The filtration models are validated by the comparisons between the modelling results and the experimental data.The elliptic equation with distributed filtration coefficients may be applied to model non-Fickian transport...... and hyperexponential deposition. The filtration model accounting for the migration of surface associated particles may be applied for non-monotonic deposition....

  1. Water Filtration Products

    Science.gov (United States)

    1986-01-01

    American Water Corporation manufactures water filtration products which incorporate technology originally developed for manned space operations. The formula involves granular activated charcoal and other ingredients, and removes substances by catalytic reactions, mechanical filtration, and absorption. Details are proprietary. A NASA literature search contributed to development of the compound. The technology is being extended to a deodorizing compound called Biofresh which traps gas and moisture inside the unit. Further applications are anticipated.

  2. Effect of the air-to-liquid ratio on treatment efficiency of wastewater in multistage BAF in a recirculating aquaculture system%封闭循环水系统生物滤池气水比对水质净化效能的影响

    Institute of Scientific and Technical Information of China (English)

    黄滨; 雷霁霖; 翟介明; 周游; 王峰; 高淳仁; 梁友

    2013-01-01

    The half-smooth tongue-sole (Cynoglossus semilaevis Gunthe) is commonly reared in a recirculating aquaculture system. We evaluated the effect of the air-to-liquid ratio on the purification efficiency, DO, and pH in the biological aerated filters of a recirculating system. The test system was maintained at (19 ±1)℃ and 15 cycles. The DO in the tank remained above 12 mg/L. As the air-to-liquid ratio increased from 0.75:1 to 1.50:1, the removal rate of TAN increased from 35.0% to 52.0%, and the removal rate of NO2-N increased from 8.2% to 44.6%. Thus, the air-to-liquid ratio had a significant impact on nitrification, whereas the influence of chemical oxygen demand (COD) removal rate was not significant. The average removal rate was 10.14%. The pH values increased from 7.97 to 8.08 but decreased between the biofilter inlet and the outlet. The optimal air-to-liquid ratio was 1.25:1. This resulted in DO levels at the inlet of the first bio-filter tank that were close to saturation. Between the first bio-filter tank and the final bio-filter tank, DO only decreased by 10%. The recirculation aquaculture system maintained the water pH value between 7.9 and 8.1. Our results provide a reference for optimization of bio-film process culture conditions.%通过在全封闭循环水系统中养殖半滑舌鳎(Cynoglossus semilaevis Gunthe),研究了不同气水比对曝气生物滤池净化效能,以及对DO、pH值的影响。结果表明:本试验系统在温度为(19±1)℃,系统循环次数为15次,养殖池DO保持在12 mg/L以上的运行条件下,随着气水比由0.75:1~1.50:1的增加,生物滤池氨氮的去除率由35.0%增加至52.0%, NO2−N的去除率由8.2%增加至44.6%,气水比对硝化反应影响显著,但对化学需氧量COD的去除率影响并不显著,其平均去除率为10.14%; pH 值有增加的趋势,生物滤池进水口到出水口的 pH 值由7.97增加至8.08;气水比最佳运行参数为1.25:1。同时还发现1级生

  3. Aerosol generation by blower motors as a bias in assessing aerosol penetration into cabin filtration systems.

    Science.gov (United States)

    Heitbrink, William A; Collingwood, Scott

    2005-01-01

    In cabin filtration systems, blower motors pressurize a vehicle cabin with clean filtered air and recirculate air through an air-conditioning evaporator coil and a heater core. The exposure reduction offered by these cabins is evaluated by optical particle counters that measure size-dependent aerosol concentration inside and outside the cabin. The ratio of the inside-to-outside concentration is termed penetration. Blower motors use stationary carbon brushes to transmit an electrical current through a rotating armature that abrades the carbon brushes. This creates airborne dust that may affect experimental evaluations of aerosol penetration. To evaluate the magnitude of these dust emissions, blower motors were placed in a test chamber and operated at 12 and 13.5 volts DC. A vacuum cleaner drew 76 m3/hour (45 cfm) of air through HEPA filters, the test chamber, and through a 5 cm diameter pipe. An optical particle counter drew air through an isokinetic sampling probe and measured the size-dependent particle concentrations from 0.3 to 15 microm. The concentration of blower motor aerosol was between 2 x 10(5) and 1.8 x 10(6) particles/m3. Aerosol penetration into three stationary vehicles, two pesticide application vehicles and one tractor were measured at two conditions: low concentration (outside in the winter) and high concentration (inside repair shops and burning incense sticks used as a supplemental aerosol source). For particles smaller than 1 microm, the in-cabin concentrations can be explained by the blower motor emissions. For particles larger than 1 microm, other aerosol sources, such as resuspended dirt, are present. Aerosol generated by the operation of the blower motor and by other sources can bias the exposure reduction measured by optical particle counters.

  4. Visualization of water flow during filtration using flat filtration materials

    Directory of Open Access Journals (Sweden)

    Hrůza Jakub

    2012-04-01

    Full Text Available Filtration materials are very important elements of some industrial appliances. Water filtration is a separation of solid materials from fluid. Solid particles are captured on the frontal area of the filtration textile and only liquid passes through it. It is important to know the filtration process in a detailed way to be able to develop filtration materials. Visualization of filtration process enables a better view of the filtration. This method also enables to determine efficiency and homogeneity of filtration using image analysis. For this purpose, a new waterfiltration measuring setup was proposed and constructed. Filtration material is mounted into the optically transparent place in the setup. Laser sheet is directed into this place as in the case of Particle Image Velocimetry measuring method. Monochrome and sensitive camera records the light scattered by seeding particles in water. The seeding particles passing through the filter serve for measuring filtration efficiency, and also for visualization of filtration process. Filtration setup enables to measure also the pressure drop and a flow. The signals are processed by National Instruments compactDAQ system and UMA software. Microfibrous and nanofibrous filtration materials are tested by this measuring method. In the case of nanofibrous filtration, appropriate size of seeding particles is needed to be used to perform a process of filtration.

  5. Modeled effectiveness of ventilation with contaminant control devices on indoor air quality in a swine farrowing facility.

    Science.gov (United States)

    Anthony, T Renée; Altmaier, Ralph; Park, Jae Hong; Peters, Thomas M

    2014-01-01

    Because adverse health effects experienced by swine farm workers in concentrated animal feeding operations (CAFOs) have been associated with exposure to dust and gases, efforts to reduce exposures are warranted, particularly in winter seasons when exposures increase due to decreased ventilation. Simulation of air quality and operating costs for ventilating swine CAFO, including treating and recirculating air through a farrowing room, was performed using mass and energy balance equations over a 90-day winter season. System operation required controlling heater operation to achieve room temperatures optimal to ensure animal health (20 to 22.5 °C). Five air pollution control devices, four room ventilation rates, and five recirculation patterns were examined. Inhalable dust concentrations were easily reduced using standard industrial air pollution control devices, including a cyclone, filtration, and electrostatic precipitator. Operating ventilation systems at 0.94 m3 s(-1) (2000 cfm) with 75 to 100% recirculation of treated air from cyclone, electrostatic precipitator, and shaker dust filtration system achieves adequate particle control with operating costs under $1.00 per pig produced ($0.22 to 0.54), although carbon dioxide (CO2) concentrations approach 2000 ppm using in-room ventilated gas fired heaters. In no simulation were CO2 concentrations below industry recommended concentrations (1540 ppm), but alternative heating devices could reduce CO2 to acceptable concentrations. While this investigation does not represent all production swine farrowing barns, which differ in characteristics including room dimensions and swine occupancy, the simulation model and ventilation optimization methods can be applied to other production sites. This work shows that ventilation may be a cost-effective control option in the swine industry to reduce exposures.

  6. Diagnostics For Recirculating And Energy Recovered Linacs

    Energy Technology Data Exchange (ETDEWEB)

    Geoffrey A. Krafft; Jean-Claude Denard

    2002-12-18

    In this paper, the electron beam diagnostics developed for recirculating electron accelerators will be reviewed. The main novelties in dealing with such accelerators are: to have sufficient information and control possibilities for the longitudinal phase space, to have means to accurately set the recirculation path length, and to have a means to distinguish the beam passes on measurements of position in the linac proper. The solutions to these problems obtained at Jefferson Laboratory and elsewhere will be discussed. In addition, more standard instrumentation (profiling and emittance measurements) will be reviewed in the context of recirculating linacs. Finally, and looking forward, electron beam diagnostics for applications to high current energy recovered linacs will be discussed.

  7. High gradient magnetic beneficiation of dry pulverized coal via upwardly directed recirculating fluidization

    Science.gov (United States)

    Eissenberg, David M.; Liu, Yin-An

    1980-01-01

    This invention relates to an improved device and method for the high gradient magnetic beneficiation of dry pulverized coal, for the purpose of removing sulfur and ash from the coal whereby the product is a dry environmentally acceptable, low-sulfur fuel. The process involves upwardly directed recirculating air fluidization of selectively sized powdered coal in a separator having sections of increasing diameters in the direction of air flow, with magnetic field and flow rates chosen for optimum separations depending upon particulate size.

  8. Microfluidic colloid filtration

    Science.gov (United States)

    Linkhorst, John; Beckmann, Torsten; Go, Dennis; Kuehne, Alexander J. C.; Wessling, Matthias

    2016-03-01

    Filtration of natural and colloidal matter is an essential process in today’s water treatment processes. The colloidal matter is retained with the help of micro- and nanoporous synthetic membranes. Colloids are retained in a “cake layer” – often coined fouling layer. Membrane fouling is the most substantial problem in membrane filtration: colloidal and natural matter build-up leads to an increasing resistance and thus decreasing water transport rate through the membrane. Theoretical models exist to describe macroscopically the hydrodynamic resistance of such transport and rejection phenomena; however, visualization of the various phenomena occurring during colloid retention is extremely demanding. Here we present a microfluidics based methodology to follow filter cake build up as well as transport phenomena occuring inside of the fouling layer. The microfluidic colloidal filtration methodology enables the study of complex colloidal jamming, crystallization and melting processes as well as translocation at the single particle level.

  9. Sodium recirculation and isotonic transport in toad small intestine

    DEFF Research Database (Denmark)

    Nedergaard, Signe Nielsen; Larsen, Erik Hviid; Ussing, Hans H.

    1999-01-01

    Small intestine; leaky epithelia; solute-coupled water transport; Na*O+ recirculation; lateral intercellular space; flux ratio analysi......Small intestine; leaky epithelia; solute-coupled water transport; Na*O+ recirculation; lateral intercellular space; flux ratio analysi...

  10. CENTRIFUGAL MEMBRANE FILTRATION

    Energy Technology Data Exchange (ETDEWEB)

    Daniel J. Stepan; Bradley G. Stevens; Melanie D. Hetland

    1999-10-01

    The overall project consists of several integrated research phases related to the applicability, continued development, demonstration, and commercialization of the SpinTek centrifugal membrane filtration process. Work performed during this reporting period consisted of Phase 2 evaluation of the SpinTek centrifugal membrane filtration technology and Phase 3, Technology Partnering. During Phase 1 testing conducted at the EERC using the SpinTek ST-IIL unit operating on a surrogate tank waste, a solids cake developed on the membrane surface. The solids cake was observed where linear membrane velocities were less than 17.5 ft/s and reduced the unobstructed membrane surface area up to 25%, reducing overall filtration performance. The primary goal of the Phase 2 research effort was to enhance filtration performance through the development and testing of alternative turbulence promoter designs. The turbulence promoters were designed to generate a shear force across the entire membrane surface sufficient to maintain a self-cleaning membrane capability and improve filtration efficiency and long-term performance. Specific Phase 2 research activities included the following: System modifications to accommodate an 11-in.-diameter, two-disk rotating membrane assembly; Development and fabrication of alternative turbulence promoter designs; Testing and evaluation of the existing and alternative turbulence promoters under selected operating conditions using a statistically designed test matrix; and Data reduction and analysis; The objective of Phase 3 research was to demonstrate the effectiveness of SpinTek's centrifugal membrane filtration as a pretreatment to remove suspended solids from a liquid waste upstream of 3M's WWL cartridge technology for the selective removal of technetium (Tc).

  11. Magnetic-seeding filtration

    Energy Technology Data Exchange (ETDEWEB)

    Depaoli, D. [Oak Ridge National Lab., TN (United States)

    1996-10-01

    This task will investigate the capabilities of magnetic-seeding filtration for the enhanced removal of magnetic and nonmagnetic particulates from liquids. This technology appies to a wide range of liquid wastes, including groundwater, process waters, and tank supernatant. Magnetic-seeding filtration can be used in several aspects of treatment, such as (1) removal of solids, particularly those in the colloidal-size range that are difficult to remove by conventional means; (2) removal of contaminants by precipitation processes; and (3) removal of contaminants by sorption processes.

  12. Filtration by eyelashes

    Science.gov (United States)

    Vistarakula, Krishna; Bergin, Mike; Hu, David

    2010-11-01

    Nearly every mammalian and avian eye is rimmed with lashes. We investigate experimentally the ability of lashes to reduce airborne particle deposition in the eye. We hypothesize that there is an optimum eyelash length that maximizes both filtration ability and extent of peripheral vision. This hypothesis is tested using a dual approach. Using preserved heads from 36 species of animals at the American Museum of Natural History, we determine the relationship between eye size and eyelash geometry (length and spacing). We test the filtration efficacy of these geometries by deploying outdoor manikins and measuring particle deposition rate as a function of eyelash length.

  13. Enlargements of filtrations and applications

    CERN Document Server

    Corcuera, J M

    2012-01-01

    In this paper we review some old and new results about the enlargement of filtrations problem, as well as their applications to credit risk and insider trading problems. The enlargement of filtrations problem consists in the study of conditions under which a semimartingale remains a semimartingale when the filtration is enlarged, and, in such a case, how to find the Doob-Meyer decomposition. Filtrations may be enlarged in different ways. In this paper we consider initial and progressive filtration enlargements made by random variables and processes. Keywords: Credit Risk, Insider Trading, Enlargement of Filtrations

  14. Water Treatment Technology - Filtration.

    Science.gov (United States)

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on filtration provides instructional materials for six competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: purposes of sedimentation basins and flocculation…

  15. Nanoparticles filtration by leaked fibrous filters

    Energy Technology Data Exchange (ETDEWEB)

    Mouret, Guillaume; Calle-Chazelet, Sandrine; Thomas, Dominique; Appert-Collin, Jean-Christophe [Nancy-Universite/LSGC/CNRS - 1 rue Grandville - BP 20451 - F-54001 Nancy Cedex (France)], E-mail: sandrine.calle@ensic.inpl-nancy.fr; Bemer, Denis [INRS - Avenue de Bourgogne - F-54501 Vandoeuvre les Nancy Cedex (France)

    2009-05-01

    The aim of this work is first to measured nanoparticles penetration through three different fiberglass filters intentionally-pierced with calibrated needles at different filtration velocity. Then a semi-empirical model based on the air flow resistances of the new and perforated filter media and on the mechanism of Brownian diffusion for the collection of ultrafine particles by the media enables to well predict the efficiency observed for all tested operating conditions. Results show that the increase of particles penetration is all the more important that the pinhole is large and that the particle diameter is low. Another result is that the filtration efficiency of the new filter media controlled the penetration. A high efficiency filter with a high resistance to air flow will be more damaged than a low efficiency filter when being perforated.

  16. Capture of CO2 From Recirculating Flue Gas Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Ochs, Thomas L.

    2003-01-01

    The possible need for an economical method for the separation of CO2 from flue gas adds a new set of challenges to power plant design, construction, operation, and maintenance. Many of the new requirements of CO2 separation are similar in nature to those addressed by the mature chemical engineering processes used in petroleum refining and industrial chemical production. Chemical engineering processes are regularly used to separate heterogeneous vapors in processes such as the fractionation of hydrocarbons or the separation of the components of air. This paper addresses the application of chemical engineering processes to the mixtures of gases and vapors found in the flue gas of recirculating boilers. Adaptation of these techniques can lead to a reduction in the energy required to capture CO2.

  17. Dynamics of microorganism populations in recirculating nutrient solutions

    Science.gov (United States)

    Strayer, R. F.

    1994-11-01

    This overview covers the basic microbial ecology of recirculating hydroponic solutions. Examples from NASA and Soviet CELSS tests and the commercial hydroponic industry will be used. The sources of microorganisms in nutrient solutions include air, water, seeds, plant containers and plumbing, biological vectors, and personnel. Microbial fates include growth, death, and emigration. Important microbial habitats within nutrient delivery systems are root surfaces, hardware surfaces (biofilms), and solution suspension. Numbers of bacteria on root surfaces usually exceed those from the other habitats by several orders of magnitude. Gram negative bacteria dominate the microflora with fungal counts usually much lower. Trends typically show a decrease in counts with increasing time unless stressed plants increase root exudates. Important microbial activities include carbon mineralization and nitrogen transformations. Important detrimental interactions include competition with plants, and human and plant pathogenesis.

  18. Air Cleaning Technologies

    Science.gov (United States)

    2005-01-01

    to remove airborne pathogens from room air depends on several factors, including the airflow rate through the unit’s filter and the airflow patterns in the room. Tested under a variety of conditions, in-room air cleaners, including portable or ceiling mounted units with either a HEPA or a non-HEPA filter, portable units with UVGI lights only, or ceiling mounted units with combined HEPA filtration and UVGI lights, have been estimated to be between 30% and 90%, 99% and 12% and 80% effective, respectively. However, and although their effectiveness is variable, the United States Centers for Disease Control and Prevention has acknowledged in-room air cleaners as alternative technology for increasing room ventilation when this cannot be achieved by the building’s HVAC system with preference given to fixed recirculating systems over portable ones. Importantly, the use of an in-room air cleaner does not preclude either the need for health care workers and visitors to use personal protective equipment (N95 mask or equivalent) when entering AII rooms or health care facilities from meeting current regulatory requirements for airflow rates (ventilation rates) in buildings and airflow differentials for effective negative-pressure rooms. The Plasmacluster ion technology, developed in 2000, is an air purification technology. Its manufacturer, Sharp Electronics Corporation, says that it can disable airborne microorganisms through the generation of both positive and negative ions. (1) The functional unit is the hydroxyl, which is a molecule comprised of one oxygen molecule and one hydrogen atom. Plasmacluster ion air purifier uses a multilayer filter system composed of a prefilter, a carbon filter, an antibacterial filter, and a HEPA filter, combined with an ion generator to purify the air. The ion generator uses an alternating plasma discharge to split water molecules into positively and negatively charged ions. When these ions are emitted into the air, they are surrounded by

  19. Preoperational test report, recirculation condenser cooling systems

    Energy Technology Data Exchange (ETDEWEB)

    Clifton, F.T.

    1997-11-04

    This represents a preoperational test report for Recirculation Condenser Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The four system provide condenser cooling water for vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102. Each system consists of a valved piping loop, a pair of redundant recirculation pumps, a closed-loop evaporative cooling tower, and supporting instrumentation; equipment is located outside the farm on concrete slabs. Piping is routed to the each ventilation condenser inside the farm via below-grade concrete trenches. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  20. Preoperational test report, recirculation condenser cooling systems

    Energy Technology Data Exchange (ETDEWEB)

    Clifton, F.T.

    1997-11-04

    This represents a preoperational test report for Recirculation Condenser Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The four system provide condenser cooling water for vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102. Each system consists of a valved piping loop, a pair of redundant recirculation pumps, a closed-loop evaporative cooling tower, and supporting instrumentation; equipment is located outside the farm on concrete slabs. Piping is routed to the each ventilation condenser inside the farm via below-grade concrete trenches. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  1. Re-circulating linac vacuum system

    Energy Technology Data Exchange (ETDEWEB)

    Wells, Russell P.; Corlett, John N.; Zholents, Alexander A.

    2003-05-09

    The vacuum system for a proposed 2.5 GeV, 10{Mu}A recirculating linac synchrotron light source [1] is readily achievable with conventional vacuum hardware and established fabrication processes. Some of the difficult technical challenges associated with synchrotron light source storage rings are sidestepped by the relatively low beam current and short beam lifetime requirements of a re-circulating linac. This minimal lifetime requirement leads directly to relatively high limits on the background gas pressure through much of the facility. The 10{Mu}A average beam current produces very little synchrotron radiation induced gas desorption and thus the need for an ante-chamber in the vacuum chamber is eliminated. In the arc bend magnets, and the insertion devices, the vacuum chamber dimensions can be selected to balance the coherent synchrotron radiation and resistive wall wakefield effects, while maintaining the modest limits on the gas pressure and minimal outgassing.

  2. High Power Picosecond Laser Pulse Recirculation

    Energy Technology Data Exchange (ETDEWEB)

    Shverdin, M Y; Jovanovic, I; Semenov, V A; Betts, S M; Brown, C; Gibson, D J; Shuttlesworth, R M; Hartemann, F V; Siders, C W; Barty, C P

    2010-04-12

    We demonstrate a nonlinear crystal-based short pulse recirculation cavity for trapping the second harmonic of an incident high power laser pulse. This scheme aims to increase the efficiency and flux of Compton-scattering based light sources. We demonstrate up to 36x average power enhancement of frequency doubled sub-millijoule picosecond pulses, and 17x average power enhancement of 177 mJ, 10 ps, 10 Hz pulses.

  3. High-power picosecond laser pulse recirculation.

    Science.gov (United States)

    Shverdin, M Y; Jovanovic, I; Semenov, V A; Betts, S M; Brown, C; Gibson, D J; Shuttlesworth, R M; Hartemann, F V; Siders, C W; Barty, C P J

    2010-07-01

    We demonstrate a nonlinear crystal-based short pulse recirculation cavity for trapping the second harmonic of an incident high-power laser pulse. This scheme aims to increase the efficiency and flux of Compton-scattering-based light sources. We demonstrate up to 40x average power enhancement of frequency-doubled submillijoule picosecond pulses, and 17x average power enhancement of 177 mJ, 10 ps, 10 Hz pulses.

  4. Design and Experimentation of Collector based Solar Dryer with Recirculation for Spices

    Directory of Open Access Journals (Sweden)

    Mr. Ganesh There

    2016-02-01

    Full Text Available Sun drying system is very common method of preserving agricultural product. Solar energy is used for heating of air and to dry food substance. In open sun drying food is unprotected from rain, wind-borne dirt and dust, infestation by insects, rodents and other animal. This process is practically attractive and environmentally sound. Shell life of agricultural product is improve by drying. This paper present design and construction of active solar dryer with recirculation technique. It consists of solar collector, drying chamber with netted trays and recirculation arrangement. Air is allowed through inlet and it is heated up in collector. Then it is circulated in drying chamber where it is utilize for drying. The design based on geographical location Wardha and meteorological data were obtained for proper design specification. Locally available materials were used for construction such as polyurethane glass, mild steel metal sheet, plywood sheet and insulating material.

  5. Evaluation of a rainbow trout (Oncorhynchus mikyss culture water recirculating system

    Directory of Open Access Journals (Sweden)

    Iván Sánchez O.

    2014-09-01

    Full Text Available Objective. To evaluate a water recirculation system for rainbow trout fish cultures at the recirculating laboratory of the Aquaculture Engineering Production Program of University of Nariño. Materials and Methods. 324 rainbow trout (Oncorhynchus mikyss fries were cultured in 12 plastic tanks with a capacity of 250 L in an aquaculture recirculating system the treatment system of which was made up by a conventional sedimentation tank, a fixed stand upflow biofilter with recycled PVC tube pieces and a natural degassing system; the sedimentation unit effluent was pumped up to a reservoir tank using a 2 HP centrifugal pump after being subject to gravity through the biofilter and to be then distributed to the 12 culture units to which a constant amount of air from a blower was injected. Results. The water treatment system removed 31% of total suspended solids, 9.5% of total ammonia nitrogen, and increased dissolved oxygen to the final effluent in 6.5%. An increase of 305% in biomass was calculated during 75 days, the mortality percentage registered throughout the study period was 4.9%. Conclusions. The water treatment system maintained the physicochemical water quality parameters within the values recommended for the species. The increase in weight and size, food conversion, mortality and biomass production reported normal values for rainbow trout fish culture in recirculating systems.

  6. Filter aids influence on pressure drop across a filtration system

    Science.gov (United States)

    Hajar, S.; Rashid, M.; Nurnadia, A.; Ammar, M. R.; Hasfalina, C. M.

    2017-06-01

    Filter aids is commonly used to reduce pressure drop across air filtration system as it helps to increase the efficiency of filtration of accumulated filter cake. Filtration velocity is one of the main parameters that affect the performance of filter aids material. In this study, a formulated filter aids consisting of PreKot™ and activated carbon mixture (designated as PrekotAC) was tested on PTFE filter media under various filtration velocities of 5, 6, and 8 m/min at a constant material loading of 0.2 mg/mm2. Results showed that pressure drop is highly influenced by filtration velocity where higher filtration velocity leads to a higher pressure drop across the filter cake. It was found that PrekotAC performed better in terms of reducing the pressure drop across the filter cake even at the highest filtration velocity. The diversity in different particle size distribution of non-uniform particle size in the formulated PrekotAC mixture presents a higher permeability causes a lower pressure drop across the accumulated filter cake. The finding suggests that PrekotAC is a promising filter aids material that helps reducing the pressure drop across fabric filtration system.

  7. [Clinical experience of automated double filtration plasmapheresis].

    Science.gov (United States)

    Lee, C T; Chuang, F R; Hsu, K T; Lam, K K; Liao, S C; Liu, C C; Chen, J B; Jang, S W; Chien, Y S; Pan, H H

    1996-12-01

    Double filtration plasmapheresis, one kind of fractionation plasmapheresis, was developed from membrane type plasmapheresis to remove only the pathogen and return the normal protein back to the patient. We started our automated double filtration plasmapheresis since December 1993. There were 13 patients who received one hundred treatments totally during one year period. And they are myasthenia gravis (8 patients); acute inflammatory demyelinating polyneuropathy (1 patient), multiple myeloma (1 patient); acquired factor VIII inhibitor (1 patient); autoimmune hemolytic anemia (1 patient); systemic lupus erythematous (1 patient). Technically double filtration plasmapheresis is easy to perform and time-saving. It also makes necessity of replacement fluid less frequent. Incidence of complication is rare, and this includes hypotension 2%, palpitation 1%, headache 1%, hemolysis 4%, air emboli 1%, high secondary pressure 2%, and no motality during our treatment. Clinical response is documented in cases of myasthenia gravis; acute inflammatory demyelinating polyneuropathy and acquired factor VIII inhibitor in our study. In conclusion, double filtration plasmapheresis is a time-saving, convenient, and safe therapeutic modality with rare complication. Because its effectiveness on limited kinds of diseases and costs relatively high price, thus plasmapheresis should be used in selected cases and treat aggressively if indicated.

  8. Recirculation, stagnation and ventilation: The 2014 legionella episode

    Science.gov (United States)

    Russo, Ana; Soares, Pedro M. M.; Gouveia, Célia M.; Cardoso, Rita M.; Trigo, Ricardo M.

    2017-04-01

    Legionella transmission through the atmosphere is unusual, but not unprecedented. A scientific paper published in 2006 reports a surge in Pas-de-Calais, France, in which 86 people have been infected by bacteria released by a cooling tower more than 6 km away [3]. Similarly, in Norway, in 2005, there was another case where contamination spread beyond 10 km, although more concentrated within a radius of 1 km from an industrial unit [2]. An unprecedented large Legionella outbreak occurred in November 2014 nearby Lisbon, Portugal. As of 7 November 2014, 375 individuals become hill and 12 died infected by the Legionella pneumophila bacteria, contracted by inhalation of steam droplets of contaminated water (aerosols). These droplets are so small that can carry the bacteria directly to the lungs, depositing it in the alveoli. One way of studying the propagation of legionella episodes is through the use of aerosol dispersion models. However, such approaches often require detailed 3D high resolution wind data over the region, which isn't often available for long periods. The likely impact of wind on legionella transmission can also be understood based on the analysis of special types of flow conditions such as stagnation, recirculation and ventilation [1, 4]. The Allwine and Whiteman (AW) approach constitutes a straightforward method to assess the assimilative and dispersal capacities of different airsheds [1,4], as it only requires hourly wind components. Thus, it has the advantage of not needing surface and upper air meteorological observations and a previous knowledge of the atmospheric transport and dispersion conditions. The objective of this study is to analyze if the legionella outbreak event which took place in November 2014 had extreme potential recirculation and/or stagnation characteristics. In order to accomplish the proposed objective, the AW approach was applied for a hindcast time-series covering the affected area (1989-2007) and then for an independent

  9. Dynamic optical filtration

    Science.gov (United States)

    Chretien, Jean-Loup (Inventor); Lu, Edward T. (Inventor)

    2005-01-01

    A dynamic optical filtration system and method effectively blocks bright light sources without impairing view of the remainder of the scene. A sensor measures light intensity and position so that selected cells of a shading matrix may interrupt the view of the bright light source by a receptor. A beamsplitter may be used so that the sensor may be located away from the receptor. The shading matrix may also be replaced by a digital micromirror device, which selectively sends image data to the receptor.

  10. Magnetic flocculation and filtration

    Energy Technology Data Exchange (ETDEWEB)

    Yiacoumi, Sotira; Chin, Ching-Ju; Yin, Tung-Yu [Georgia Inst. of Tech., Atlanta, GA (United States). School of Civil and Environmental Engineering; Tsouris, C., DePaoli, D.W.; Chattin, M.R.; Spurrier, M. [Oak Ridge National Lab., TN (United States)

    1996-10-01

    A model is available in predicting flocculation frequencies between particles of various properties under the influence of a magnetic field. This model provides a basic understanding of fundamental phenomena, such as particle-particle and particle-collector interactions, occurring in HGMF (high gradient magnetic field), and will be extended to describe experimental data of particle flocculation and filtration and predict the performance of high- gradient magnetic filters. It is also expected that this model will eventually lead to a tool for design and optimization of magnetic filters for environmental, metallurgical, biochemical, and other applications.

  11. 40 CFR 86.165-12 - Air conditioning idle test procedure.

    Science.gov (United States)

    2010-07-01

    ... the vehicle using one full Urban Dynamometer Driving Schedule. Ensure that the vehicle has stabilized... lowest setting that continues to provide air flow. Recirculation shall be turned off except that if the system defaults to a recirculation mode when set to maximum cooling and maintains recirculation with the...

  12. Magnetic-seeding filtration

    Energy Technology Data Exchange (ETDEWEB)

    DePaoli, D.W.; Tsouris, C. [Oak Ridge National Lab., TN (United States); Yiacoumi, Sotira

    1997-10-01

    Magnetic-seeding filtration is a technology under development for the enhanced removal of magnetic and non-magnetic particulates from liquids. This process involves the addition of a small amount of magnetic seed particles (such as naturally occurring iron oxide) to a waste suspension, followed by treatment with a magnetic filter. Non-magnetic and weakly magnetic particles are made to undergo nonhomogeneous flocculation with the seed particles, forming flocs of high magnetic susceptibility that are readily removed by a conventional high-gradient magnetic filter. This technology is applicable to a wide range of liquid wastes, including groundwater, process waters, and tank supernatants. Magnetic-seeding filtration may be used in several aspects of treatment, such as (1) removal of solids, particularly those in the colloidal size range that are difficult to remove by conventional means; (2) removal of contaminants by precipitation processes; and (3) removal of contaminants by sorption processes. Waste stream characteristics for which the technology may be applicable include (1) particle sizes ranging from relatively coarse (several microns) to colloidal particles, (2) high or low radiation levels, (3) broad-ranging flow rates, (4) low to moderate solids concentration, (5) cases requiring high decontamination factors, and (6) aqueous or non-aqueous liquids. At this point, the technology is at the bench-scale stage of development; laboratory studies and fundamental modeling are currently being employed to determine the capabilities of the process.

  13. The bio-ethanol production with the thin stillage recirculation

    Directory of Open Access Journals (Sweden)

    M. Rakin

    2009-01-01

    Full Text Available In this paper, the bioethanol production with the thin stillage recirculation in mashing was investigated. The mashing was performed with recirculation of: 0, 10, 20 and 30 % of the thin stillage. The thin stillage recirculation was repeated six times. In the experiment without the thin stillage, the recirculation bioethanol yield (compared to the theoretical yield was 97.96 %, which implicates that the experiment conditions were chosen and performed well. With the addition of the thin stillage, the bioethanol yield increased and was above 100 %. Higher bioethanol yield than 100 % can be explained by the fact that the thin stillage contains carbohydrates, amino acids and yeast cells degradation products. The bioethanol yield increased with the increased number of thin stillage recirculation cycles. Dry matter content in fermenting slurry increased with the increased thin stillage quantity and the number of the thin stillage recirculation cycles (8.04 % for the first and 9.40 % for the sixth cycle. Dry matter content in thin stillage increased with the increased thin stillage quantity and the number of thin stillage recirculation cycles. Based on the obtained results it can be concluded that thin stillage recirculation increased the bioethanol yield. The highest bioethanol yields were obtained with recirculation of 10% thin stillage.

  14. Evaluation on Biofilter in Recirculating Integrated Multi-Trophic Aquaculture

    Directory of Open Access Journals (Sweden)

    S. Sumoharjo

    2013-06-01

    Full Text Available Integrated multi-trophic aquaculture pays more attention as a bio-integrated food production system that serves as a model of sustainable aquaculture, minimizes waste discharge, increases diversity and yields multiple products. The objectives of this research were to analyze the efficiency of total ammonia nitrogen biofiltration and its effect on carrying capacity of fish rearing units. Pilot-scale bioreactor was designed with eight run-raceways (two meters of each that assembled in series. Race 1-3 were used to stock silky worm (Tubifex sp as detrivorous converter, then race 4-8 were used to plant three species of leaf-vegetable as photoautotrophic converters, i.e; spinach (Ipomoea reptana, green mustard (Brassica juncea and basil (Ocimum basilicum. The three plants were placed in randomized block design based on water flow direction. Mass balance of nutrient analysis, was applied to figure out the efficiency of bio-filtration and its effect on carrying capacity of rearing units. The result of the experiment showed that 86.5 % of total ammonia nitrogen removal was achieved in 32 days of culturing period. This efficiency able to support the carrying capacity of the fish tank up to 25.95 kg/lpm with maximum density was 62.69 kg/m3 of fish biomass productionDoi: http://dx.doi.org/10.12777/ijse.4.2.2013.80-85 [How to cite this article: Sumoharjo, S.  and Maidie, A. (2013. Evaluation on Biofilter in Recirculating Integrated Multi-Trophic Aquaculture.  International Journal of  Science and Engineering, 4(2,80-85. Doi: http://dx.doi.org/10.12777/ijse.4.2.2013.80-85

  15. Triplet Focusing for Recirculating Linear Muon Accelerators

    CERN Document Server

    Keil, Eberhard

    2001-01-01

    Focusing by symmetrical triplets is studied for the linear accelerator lattices in recirculating muon accelerators with several passes where the ratio of final to initial muon energy is about four. Triplet and FODO lattices are compared. At similar acceptance, triplet lattices have straight sections for the RF cavities that are about twice as long as in FODO lat-tices. For the same energy gain, the total lengths of the linear accelerators with triplet lattices are about the same as of those with FODO lattices.

  16. In-tank recirculating arsenic treatment system

    Science.gov (United States)

    Brady, Patrick V.; Dwyer, Brian P.; Krumhansl, James L.; Chwirka, Joseph D.

    2009-04-07

    A low-cost, water treatment system and method for reducing arsenic contamination in small community water storage tanks. Arsenic is removed by using a submersible pump, sitting at the bottom of the tank, which continuously recirculates (at a low flow rate) arsenic-contaminated water through an attached and enclosed filter bed containing arsenic-sorbing media. The pump and treatment column can be either placed inside the tank (In-Tank) by manually-lowering through an access hole, or attached to the outside of the tank (Out-of-Tank), for easy replacement of the sorption media.

  17. Multi-frequency recirculating planar magnetrons

    Science.gov (United States)

    Greening, Geoffrey B.; Jordan, Nicholas M.; Exelby, Steven C.; Simon, David H.; Lau, Y. Y.; Gilgenbach, Ronald M.

    2016-08-01

    The multi-frequency recirculating planar magnetron (MFRPM) is the first magnetron capable of simultaneous generation of significantly different output frequencies (1 and 2 GHz) in a single operating pulse. Design and simulation of a prototype MFRPM were followed by hardware fabrication and experimental verification using the Michigan Electron Long Beam Accelerator with a Ceramic insulator at -300 kV, 1-5 kA, and 0.14-0.23 T axial magnetic field. Preliminary results demonstrated simultaneous generation of microwave pulses near 1 GHz and 2 GHz at powers up to 44 MW and 21 MW, respectively, with peak total efficiencies up to 9%.

  18. Effectiveness of Floating Micro-Bead Bio-Filter for Ornamental Fish in a Re-Circulating Aquaculture System

    OpenAIRE

    R Fadhil

    2011-01-01

    Bio-filtration has been widely used in re-circulating aquaculture system to remove waste and to convert toxic ammonia andnitrite into safe end products ornamental fish and other aquatic organisms. However, the study of micro-bead usage as the filter medium has not yet been broadened and thoroughly developed. Therefore, the aim of this study is to construct a biological filter made from polyethylene micro-bead as the filter medium and to analyze its effectiveness in removingwaste as well as in...

  19. Nonlinear EGR and VGT Control with Integral Action for Diesel Engines Régulation de Recirculation des Gaz d’Echappement (RGE et de Turbine à Géométrie Variable (TGV non linéaire avec action intégrée pour moteurs Diesel

    Directory of Open Access Journals (Sweden)

    Wahlström J.

    2011-10-01

    Full Text Available A nonlinear multivariable control design with integral action is proposed and investigated for control of Exhaust Gas Recirculation (EGR and Variable Geometry Turbine (VGT in heavy duty Diesel engines. The main control goal is to regulate oxygen/fuel ratio and intake manifold EGR-fraction, and they are specified in an outer loop. These are chosen as main performance variables since they are strongly coupled to the emissions. An existing nonlinear control design based on feedback linearization is extended with integral action. In particular, the control design method utilizes a control Lyapunov function, inverse optimal control, and a nonlinear input transformation. Comparisons between different control structures are performed in simulations showing the following four points. Firstly, integral action is necessary to handle model errors so that the controller can track the performance variables specified in the outer loop. Secondly, the proposed control design handles the nonlinear effects in the Diesel engine that results in less control errors compared to a control structure with PID controllers. Thirdly, it is important to use the input transformation and it is sufficient to use a control structure with PID controllers and input transformation to handle the nonlinear effects. Fourthly, the proposed control design is sensitive to model errors in the input transformation while a control structure with PID controllers and input transformation handles these model errors. Une conception de régulation non linéaire à variables multiples avec action intégrée est proposée et étudiée pour une régulation de la Recirculation des Gaz d’Echappement (RGE et une Turbine à Géométrie Variable (TGV au sein de moteurs Diesel à usage industriel. L’objectif principal de la régulation consiste à réguler le rapport oxygène / carburant et la fraction de RGE de tubulure d’admission, qui sont spécifiés au sein d’une boucle extérieure. Ceux

  20. Modus of filtration.

    Science.gov (United States)

    Meltzer, Theodore H

    2006-01-01

    Experience teaches that particles larger than the pores of a filter cannot negotiate its passage. Other retention mechanisms are less obvious than sieve retention or size exclusion. They are electrical in nature, and find expression in the bonding alliances that mutually attract (or repel) filters and particles. The influence of hydrogen bonds, of van der Waals forces, of hydrophobic adsorptions, and of transient polarities on particle retentions are set forth in terms of the double electrical layer concept that also governs colloidal destabilizations. The origins of differences in membrane porosities is explained, as also the importance of the filtration conditions. The singularity of the particle-fluid-filter relationship on organism and/or pore size alteration is stressed.

  1. Filtration properties of nonwovens.

    Science.gov (United States)

    Gador, W; Jankowska, E

    1999-01-01

    This paper presents the results and conclusions from experimental investigations concerning filtration properties of nonwovens. The needled nonwovens were made from polyester fibres (PTE) with average fibre diameter 12 micrometres and polypropylene fibres (PP) with average fibre diameter 32 micrometres. Nonwovens were produced out of each of those fibres or out of a mixture of polyester and polypropylene fibres. This paper also presents investigations of nonwoven fabric made of polypropylene fibres (PP) with average fibre diameter 2.6 micrometres, which was formed according to melt-blown technology. Oil mist, as challenge aerosol, was used to evaluate the performance of filter media at various aerosol velocities. The average oil mist test aerosol particle diameter was 0.3 micrometre. Filter penetration was measured at oil mist concentration 0.24 g/m(3).

  2. IC ENGINE SUPERCHARGING AND EXHAUST GAS RECIRCULATION USING JET COMPRESSOR

    Directory of Open Access Journals (Sweden)

    Adhimoulame Kalaisselvane

    2010-01-01

    Full Text Available Supercharging is a process which is used to improve the performance of an engine by increasing the specific power output whereas exhaust gas recirculation reduces the NOx produced by engine because of supercharging. In a conventional engine, supercharger functions as a compressor for the forced induction of the charge taking mechanical power from the engine crankshaft. In this study, supercharging is achieved using a jet compressor. In the jet compressor, the exhaust gas is used as the motive stream and the atmospheric air as the propelled stream. When high pressure motive stream from the engine exhaust is expanded in the nozzle, a low pressure is created at the nozzle exit. Due to this low pressure, atmospheric air is sucked into the expansion chamber of the compressor, where it is mixed and pressurized with the motive stream. The pressure of the mixed stream is further increased in the diverging section of the jet compressor. A percentage volume of the pressurized air mixture is then inducted back into the engine as supercharged air and the balance is let out as exhaust. This process not only saves the mechanical power required for supercharging but also dilutes the constituents of the engine exhaust gas thereby reducing the emission and the noise level generated from the engine exhaust. The geometrical design parameters of the jet compressor were obtained by solving the governing equations using the method of constant rate of momentum change. Using the theoretical design parameters of the jet compressor, a computational fluid dinamics analysis using FLUENT software was made to evaluate the performance of the jet compressor for the application of supercharging an IC engine. This evaluation turned out to be an efficient diagnostic tool for determining performance optimization and design of the jet compressor. A jet compressor was also fabricated for the application of supercharging and its performance was studied.

  3. Production of market size pikeperch (Sander lucioperca) in a pilot recirculation system

    NARCIS (Netherlands)

    Schram, E.; Philipsen, E.

    2003-01-01

    A pilot recirculation system was designed and constructed to investigate the production characteristics of pikeperch in recirculation systems. The design is based on a recirculation system for eel production.

  4. Effect of self recirculation casing treatment on the performance of a turbocharger centrifugal compressor

    Science.gov (United States)

    Gancedo, Matthieu

    Increase in emission regulations in the transport industry brings the need to have more efficient engines. A path followed by the automobile industry is to downsize the size of the internal combustion engine and increase the air density at the intake to keep the engine power when needed. Typically a centrifugal compressor is used to force the air into the engine, it can be powered from the engine shaft (superchargers) or extracting energy contained into the hot exhaust gases with a turbine (turbochargers). The flow range of the compressor needs to match the one of the engine. However compressors mass flow operating range is limited by choke on the high end and surge on the low end. In order to extend the operation at low mass flow rates, the use of passive devices for turbocharger centrifugal compressors was explored since the late 80's. Hence, casing treatments including flow recirculation from the inducer part of the compressor have been shown to move the surge limit to lower flows. Yet, the working mechanisms are still not well understood and thus, to optimize the design of this by-pass system, it is necessary to determine the nature of the changes induced by the device both on the dynamic stability of the pressure delivery and on the flow at the inlet. The compressor studied here features a self-recirculating casing treatment at the inlet. The recirculation passage could be blocked to carry a direct comparison between the cases with and without the flow feature. To grasp the effect on compressor stability, pressure measurements were taken in the different constituting elements of the compressor. The study of the mean pressure variations across the operating map showed that the tongue region is a limiting element. Dynamic pressure measurements revealed that the instabilities generated near the inducer when the recirculation is blocked increase the overall instability levels at the compressor outlet and propagating pressure waves starting at the tongue occurred

  5. A Study of NO{sub x} Reduction by Fuel Injection Recirculation

    Energy Technology Data Exchange (ETDEWEB)

    Feese, J.J.; Turns, S.R.

    1996-08-01

    Flue-gas recirculation (FGR) is a well-known method used to control oxides of nitrogen (NO{sub X}) in industrial burner applications. Recent small- and large-scale experiments in natural-gas fired boilers have shown that introducing the recirculated flue gases with the fuel results in a much greater reduction in NO{sub X}, per unit mass of gas recirculated, in comparison to introducing the flue gases with the combustion air. That fuel injection recirculation (FIR) is more effective than windbox FGR is quite remarkable. At present, however, there is no definitive understanding of why FIR is more effective than conventional FGR. The objective of the present investigation is to ascertain whether or not chemical and/or molecular transport effects alone can explain the differences in NO{sub X} reduction observed between FIR and FGR by studying laminar diffusion flames. The purpose of studying laminar flames is to isolate chemical effects from the effects of turbulent mixing and heat transfer, which are inherent in practical boilers. Numerical simulations of H{sub 2}-air and CH{sub 4}-air counterflow diffusion flames using full kinetics were performed and NO{sub X} emission indices calculated for various conditions. Studies were conducted in which a N{sub 2} diluent was added either on the fuel- or air-side of the flame for conditions of either fixed initial velocities or fixed fuel mass flux. Results from these simulation studies indicate that a major factor in diluent effectiveness is the differential effect on flame zone residence times associated with fuel-side verses air-side dilution. Simulations in which flow velocities were fixed as diluent was added either to the air or fuel stream showed lower NO{sub X} emissions for air-side dilution; however, if instead, fuel mass fluxes were fixed as diluent was added, which results in an increase in the velocity of the streams, fuel-side dilution was more effective. These results were independent of whether H{sub 2} or Ch

  6. Ceramic Ultra Filtration Membrane Bioreactor for Domestic Wastewater Treatment

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A long term domestic wastewater treatment experiment was conducted using a recirculating ceramic ultra filtration membrane bioreactor (CUFMB) system. Three experiments were run with a hydraulic retention time of 5h, sludge retention times of 5d, 15d, and 30d and a membrane surface flow rate of 4m/s. The experiment studied the membrane fouling mechanism and cleaning techniques. The results show that a CUFMB system can provide continuous good quality effluent which is completely acceptable for reuse. The system is also not affected by fluctuations of the inlet flow. The CUFMB sludge loading rate is similar to that of conventional biological treatment units. However, the volumetric loading rate of the CUFMB is 24 times that of conventional biological treatment units. Membrane fouling occurs due to channel clogging, which could be easily removed, and surface fouling, which can be effectively removed using the method described in this work which includes water rinsing, base cleaning, and acid washing.

  7. Beam Dynamics Studies in Recirculating Machines

    CERN Document Server

    Pellegrini, Dario; Latina, A

    The LHeC and the CLIC Drive Beam share not only the high-current beams that make them prone to show instabilities, but also unconventional lattice topologies and operational schemes in which the time sequence of the bunches varies along the machine. In order to asses the feasibility of these projects, realistic simulations taking into account the most worrisome effects and their interplays, are crucial. These include linear and non-linear optics with time dependent elements, incoherent and coherent synchrotron radiation, short and long-range wakefields, beam-beam effect and ion cloud. In order to investigate multi-bunch effects in recirculating machines, a new version of the tracking code PLACET has been developed from scratch. PLACET2, already integrates most of the effects mentioned before and can easily receive additional physics. Its innovative design allows to describe complex lattices and track one or more bunches accordingly to the machine operation, reproducing the bunch train splitting and recombinat...

  8. Nutrient Management in Recirculating Hydroponic Culture

    Science.gov (United States)

    Bugbee, Bruce

    2004-01-01

    There is an increasing need to recirculate and reuse nutrient solutions in order to reduce environmental and economic costs. However, one of the weakest points in hydroponics is the lack of information on managing the nutrient solution. Many growers and research scientists dump out nutrient solutions and refill at weekly intervals. Other authors have recommended measuring the concentrations of individual nutrients in solution as a key to nutrient control and maintenance. Dumping and replacing solution is unnecessary. Monitoring ions in solution is not always necessary; in fact the rapid depletion of some nutrients often causes people to add toxic amounts of nutrients to the solution. Monitoring ions in solution is interesting, but it is not the key to effective maintenance.

  9. Reduced bleed air extraction for DC-10 cabin air conditioning

    Science.gov (United States)

    Newman, W. H.; Viele, M. R.; Hrach, F. J.

    1980-01-01

    It is noted that a significant fuel savings can be achieved by reducing bleed air used for cabin air conditioning. Air in the cabin can be recirculated to maintain comfortable ventilation rates but the quality of the air tends to decrease due to entrainment of smoke and odors. Attention is given to a development system designed and fabricated under the NASA Engine Component Improvement Program to define the recirculation limit for the DC-10. It is shown that with the system, a wide range of bleed air reductions and recirculation rates is possible. A goal of 0.8% fuel savings has been achieved which results from a 50% reduction in bleed extraction from the engine.

  10. Problems of multiphase fluid filtration

    CERN Document Server

    Konovalov, AN

    1994-01-01

    This book deals with a spectrum of problems related to the mathematical modeling of multiphase filtration. Emphasis is placed on an inseparable triad: model - algorithm - computer code. An analysis of new and traditional filtration problems from the point of view of both their numerical implementation and the reproduction of one or another technological characteristics of the processes under consideration is given. The basic principles which underlie the construction of efficient numerical methods taking into account the filtration problems are discussed: non-evolutionary nature, degeneration,

  11. Characteristics of soot formation and burnout in turbulent recirculating flames

    Energy Technology Data Exchange (ETDEWEB)

    Touati, A.

    1987-01-01

    The present study represents an investigation of the effect of fuel type, fuel stream heat content, nitrogen dilution, and air jet velocity on soot formation rates and particle burnout in a highly recirculating, turbulent-type flame. Soot particle size and flux measurements have been made using an optical probe based on a large angle ratioing technique to measure the intensity of forward scattered light from individual particles at two off-axis angles. Chemical analyses of soot samples have been made using a gas chromatograph with a flame ionization detector (FID), and a morphological analysis of soot samples has been made using a scanning electron microscope (SEM). Physical probes have been used for temperature measurements and extraction of soot particles. Chemical analysis of the composition of the polycyclic aromatic hydrocarbons (PAHs) extracted from soot samples collected at the face of the burner and on a filter located downstream in the exhaust system suggests that multiple, convergent pathways, rather than one chemical mechanism, lead to the formation of high molecular weight PAHs and soot. Net soot production was found to be the result of the competition of soot particle formation and burnout. The fuel type and the fuel stream heat content appear the main parameters that determine the flame's propensity to soot. The addition of nitrogen to a fuel stream increases the difference in the net soot production among the fuel investigated. Dilution by nitrogen decreases more effectively the oxidation rate of soot particles in flames that use fuels of lower heat content.

  12. A detailed BWR recirculation loop model for RELAP

    Energy Technology Data Exchange (ETDEWEB)

    Araiza-Martínez, Enrique, E-mail: enrique.araiza@inin.gob.mx; Ortiz-Villafuerte, Javier, E-mail: javier.ortiz@inin.gob.mx; Castillo-Durán, Rogelio, E-mail: rogelio.castillo@inin.gob.mx

    2017-01-15

    Highlights: • A new detailed BWR recirculation loop model was developed for RELAP. • All jet pumps, risers, manifold, suction and control valves, and recirculation pump are modeled. • Model is tested against data from partial blockage of two jet pumps. • For practical applications, simulation results showed good agreement with available data. - Abstract: A new detailed geometric model of the whole recirculation loop of a BWR has been developed for the code RELAP. This detailed model includes the 10 jet pumps, 5 risers, manifold, suction and control valves, and the recirculation pump, per recirculation loop. The model is tested against data from an event of partial blockage at the entrance nozzle of one jet pump in both recirculation loops. For practical applications, simulation results showed good agreement with data. Then, values of parameters considered as figure of merit (reactor power, dome pressure, core flow, among others) for this event are compared against those from the common 1 jet pump per loop model. The results show that new detailed model led to a closer prediction of the reported power change. The detailed recirculation loop model can provide more reliable boundary condition data to a CFD models for studies of, for example, flow induced vibration, wear, and crack initiation.

  13. A ZigBee Wireless Sensor Network for Monitoring an Aquaculture Recirculating System

    Directory of Open Access Journals (Sweden)

    Francisco J. Espinosa-Faller

    2012-06-01

    Full Text Available A ZigBee wireless sensor network was developed for monitoring an experimental aquaculture recirculating system.Temperature, dissolved oxygen, water and air pressure as well as electric current sensors were included in the setup.The high fish densities required in these systems to become economically viable present a case where sensornetworks can be applied to preserve a healthy livestock and to reduce the risk of failures that end up in the loss ofproduction. Modules for reading and transmitting sensor values through a ZigBee wireless network were developedand tested. The modules were installed in an aquaculture recirculating system to transmit sensor values to thenetwork coordinator. A monitoring program was created in order to display and store sensor values and to comparethem with reference limits. An alert is emitted in case reference limits have been reached. E-mail and an SMSmessage alert can also be sent to the cellular phone of the system administrator, so immediate action can be taken. Aweb interface allows Internet access to the sensor values. The present work demonstrates the applicability of ZigBeewireless sensor network technology to aquaculture recirculating systems.

  14. Investigation of a combined gas-steam system with flue gas recirculation

    Directory of Open Access Journals (Sweden)

    Chmielniak Tadeusz

    2016-06-01

    Full Text Available This article presents changes in the operating parameters of a combined gas-steam cycle with a CO2 capture installation and flue gas recirculation. Parametric equations are solved in a purpose-built mathematical model of the system using the Ebsilon Professional code. Recirculated flue gases from the heat recovery boiler outlet, after being cooled and dried, are fed together with primary air into the mixer and then into the gas turbine compressor. This leads to an increase in carbon dioxide concentration in the flue gases fed into the CO2 capture installation from 7.12 to 15.7%. As a consequence, there is a reduction in the demand for heat in the form of steam extracted from the turbine for the amine solution regeneration in the CO2 capture reactor. In addition, the flue gas recirculation involves a rise in the flue gas temperature (by 18 K at the heat recovery boiler inlet and makes it possible to produce more steam. These changes contribute to an increase in net electricity generation efficiency by 1%. The proposed model and the obtained results of numerical simulations are useful in the analysis of combined gas-steam cycles integrated with carbon dioxide separation from flue gases.

  15. Technology Review of Modern Gas Turbine Inlet Filtration Systems

    Directory of Open Access Journals (Sweden)

    Melissa Wilcox

    2012-01-01

    Full Text Available An inlet air filtration system is essential for the successful operation of a gas turbine. The filtration system protects the gas turbine from harmful debris in the ambient air, which can lead to issues such as FOD, erosion, fouling, and corrosion. These issues if not addressed will result in a shorter operational life and reduced performance of the gas turbine. Modern day filtration systems are comprised of multiple filtration stages. Each stage is selected based on the local operating environment and the performance goals for the gas turbine. Selection of these systems can be a challenging task. This paper provides a review of the considerations for selecting an inlet filtration system by covering (1 the characteristics of filters and filter systems, (2 a review of the many types of filters, (3 a detailed look at the different environments where the gas turbine can operate, (4 a process for evaluating the site where the gas turbine will be or is installed, and (5 a method to compare various filter system options with life cycle cost analysis.

  16. Design and performance of a trickling air biofilter for chlorobenzene and o-dichlorobenzene vapors.

    Science.gov (United States)

    Oh, Y S; Bartha, R

    1994-01-01

    From contaminated industrial sludge, two stable multistrain microbial enrichments (consortia) that were capable of rapidly utilizing chlorobenzene and o-dichlorobenzene, respectively, were obtained. These consortia were characterized as to their species composition, tolerance range, and activity maxima in order to establish and maintain the required operational parameters during their use in biofilters for the removal of chlorobenzene contaminants from air. The consortia were immobilized on a porous perlite support packed into filter columns. Metered airstreams containing the contaminant vapors were partially humidified and passed through these columns. The vapor concentrations prior to and after biofiltration were measured by gas chromatography. Liquid was circulated concurrently with the air, and the device was operated in the trickling air biofilter mode. The experimental arrangement allowed the independent variation of liquid flow, airflow, and solvent vapor concentrations. Bench-scale trickling air biofilters removed monochlorobenzene, o-dichlorobenzene, and their mixtures at rates of up to 300 g of solvent vapor h(-1) m(-3) filter volume. High liquid recirculation rates and automated pH control were critical for stable filtration performance. When the accumulating NaCl was periodically diluted, the trickling air biofilters continued to remove chlorobenzenes for several months with no loss of activity. The demonstrated high performance and stability of the described trickling air biofilters favor their use in industrial-scale air pollution control. PMID:8085815

  17. Filtration and compression of organic materials

    DEFF Research Database (Denmark)

    Christensen, Morten Lykkegaard; Keiding, Kristian

    The conventional filtration theory has been based on filtrations of incompressible particles such as anatase, kaolin and clay. The filtration models have later been used for organic slurries but can often not explain the observed experimental data. At constant pressure, the filtrate volume does...

  18. 40 CFR 141.73 - Filtration.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Filtration. 141.73 Section 141.73... PRIMARY DRINKING WATER REGULATIONS Filtration and Disinfection § 141.73 Filtration. A public water system..., and does not meet all of the criteria in § 141.71 (a) and (b) for avoiding filtration, must...

  19. Modeling and simulation of the bioprocess with recirculation

    Directory of Open Access Journals (Sweden)

    Žerajić Stanko

    2007-01-01

    Full Text Available The bioprocess models with recirculation present an integration of the model of continuous bioreaction system and the model of separation system. The reaction bioprocess is integrated with separation the biomass, formed product, no consumed substrate or inhibitory substance. In this paper the simulation model of recirculation bioprocess was developed, which may be applied for increasing the biomass productivity and product biosynthesis increasing the conversion of a substrate-to-product, mixing efficiency and secondary C02 separation. The goal of the work is optimal bioprocess configuration, which is determined by simulation optimization. The optimal hemostat state was used as referent. Step-by-step simulation method is necessary because the initial bioprocess state is changing with recirculation in each step. The simulation experiment confirms that at the recirculation ratio a. = 0.275 and the concentration factor C = 4 the maximum glucose conversion to ethanol and at a dilution rate ten times larger.

  20. A closed recirculated sea-water system

    Science.gov (United States)

    1967-01-01

    Study of a virus disease in the chinook salmon (Oncorhynchus tshawytscha) necessitated the use of a marine environment to study the long range effects of the disease and to complete the life cycle of its etiologic agent. A closed recirculated sea-water system was designed for use under experimental laboratory conditions so that controlled studies of the disease could be made. As others may wish to do marine environment studies in the laboratory, the design and operation of our system are presented. Other systems currently in use have been described by Chin (1959), DeWitt and Salo (1960), McCrimmon and Berst (1966), and the authors of collected papers edited by Clark and Clark (1964). Preparatory to the design and construction of the system in use in this laboratory, visits were made to marine systems in use at the University of Washington's College of Fisheries, Seattle, -washington, and Friday Harbor Laboratory, San Juan Island, Washington; the Washington State Department of Fisheries' Point whitney Shellfish Laboratory, Brinnon, Washington; Humboldt State College, Arcata, California; and the Steinhart Aquarium of the California Academy of Science, San Francisco, California.

  1. Modeling of TAN in recirculating aquaculture systems by AQUASIM

    DEFF Research Database (Denmark)

    Arvin, Erik; Pedersen, Lars-Flemming

    2011-01-01

    Modeling of total ammonium nitrogen (TAN) in recirculating aquaculture systems (RAS) contribute to identifying and quantifying the most important processes and their relative contribution to removal of TAN. AQUASIM is a flexible modular simulation system for water quality in natural and technical...... systems developed by EAWAG (Reichert, 1994). AQUASIM allows simulating complex biological, chemical and physical processes in standardized hydraulic systems. We used AQUASIM to model the steady state TAN concentrations in 12 experimental recirculating aquaculture systems (RAS) operated by DTU AQUA...

  2. The effect of aeration and recirculation on a sand-based hybrid constructed wetland treating low-strength domestic wastewater.

    Science.gov (United States)

    Zapater-Pereyra, M; Kyomukama, E; Namakula, V; van Bruggen, J J A; Lens, P N L

    2016-08-01

    The Duplex-constructed wetland (CW) is a hybrid system composed of a vertical flow (VF) CW on top of a horizontal flow filter (HFF). Each compartment is designed to play a different role: aerobic treatment in the VF CW due to intermittent feeding and anoxic treatment in the HFF due to saturated conditions. Three Duplex-CWs were used in this study: Control, Aerated and Recirculating. The role of each compartment was tested for pollutant removal and micro-invertebrate abundance. In all systems, the VF CW removed mainly organic matter, solids and NH4(+)-N. Pathogens were removed in both compartments. Likewise, total nitrogen removal occurred in both compartments, only the Recirculating HFF was not able to denitrify the nitrogen due to the slightly more oxic conditions as compared to the other systems. All systems met discharge guidelines for organic matter, but only the Control and Aerated systems met those for total nitrogen. At the applied loading rates, the pollutant removal was not significantly enhanced by the use of aeration and recirculation. Therefore, operation as in the Control system, without aeration or recirculation, is recommended for the tested Duplex-CWs. If artificial aeration will be used in CWs, the support material should be carefully selected to allow a proper air distribution.

  3. Selection оf Parameters for System of Diesel Engine Exhaust Gas Recirculation

    Directory of Open Access Journals (Sweden)

    G. M. Kukharionok

    2014-01-01

    Full Text Available The paper presents research results of various methods for recirculation of diesel engine exhaust gases. An influence of recirculation parameters on economic and ecological diesel engine characteristics has been evaluated in the paper. The paper considers an influence of turbocharger configuration on the intensity of gas recirculation. Specific features of the recirculation system operation in dynamic modes have been shown in the paper. The paper provides recommendations for selection of a diesel engine exhaust gas recirculation system.

  4. Performance Study of Ceramic Filter Module in Recirculated Aquaculture System (RAS)

    Science.gov (United States)

    Ng, L. Y.; Ng, C. Y.

    2017-06-01

    The growth of world population has led to significant increase in seafood demand over the world. Aquaculture has been widely accepted by many countries to increase the seafood production owing to the decline of natural seafood resources. The aquaculture productivity, however, is directly linked to the pond water quality. In this study, attempts were made to employ ceramic micro-filter to improve the pond water quality through filtration processes. There were two batches of filtration processes, short term (1 hour) and long term (48 hours). Significant improvements on real pond water quality were recorded through the short term microfiltration process, which reduced turbidity (96%), total suspended solids (TSS) (80%), biochemical oxygen demand (BOD) (72%), chemical oxygen demand (COD) (55%), ammonia (60%), nitrate (96%) and phosphorus (83%). The long term filtration process also showed high efficiency in the removal of solid particle and organic matters. The results showed that all of the parameters were successfully reduced to acceptable ranges (turbidity<80 NTU, TSS<400 mg/L, BOD<5 mg/L, COD<70 mg/L, phosphate<3 mg/L and ammonia<0.05 mg/L) for fish culturing activity. Based on current study, there was a drastic increase in nitrate content after 24 hours due to the nitrification process by regenerated bacteria in the filtered pond water. Current study showed that the microfiltration using ceramic micro-filter has high potential to be used in recirculating aquaculture system throughout the aquaculture activities in order to maintain the pond water quality, thus, increase the survival rate of cultured species.

  5. Characterization, Washing, Leaching, and Filtration of C-104 Sludge

    Energy Technology Data Exchange (ETDEWEB)

    KP Brooks; PR Bredt; GR Golcar; SA Hartley; LK Jagoda; KG Rappe; MW Urie

    2000-06-09

    Approximately 1,400 g of wet Hanford Tank C-104 Sludge was evaluated by Battelle for the high-level waste (HLW) pretreatment processes of ultrafiltration, dilute caustic washing, and elevated-temperature caustic leaching. The filterability of diluted C-104 sludge was measured with a 0.1-{micro}m sintered metal Mott filter using a 24-inch-long, single-element, crossflow filtration system (cells unit filter [CUF]). While the filtrate was being recirculated prior to washing and leaching, a 6.9 wt% solids slurry was evaluated with a matrix of seven 1-hour conditions of varying trans-membrane pressure (30 to 70 psid) and axial velocity (9 to 15 ft/s). The filtrate flux and backpulse efficiency were determined for each condition. The slurry was concentrated to 23 wt% solids, a second matrix of six 1-hour conditions was performed, and data analogous to that recorded in the first matrix were obtained. The low-solids-concentration matrix produced filtrate flux rates that ranged from 0.038 to 0.083 gpm/ft{sup 2}. The high-solids-concentration matrix produced filtrate flux rates that ranged from 0.0095 to 0.0172 gpm/ft{sup 2}. In both cases, the optimum filtrate flux was at the highest axial velocity (15 ft/s) and transmembrane pressure had little effect. Nearly all of the measured filtrate fluxes were more than an order of magnitude greater than the required plant flux for C-104 of 0.00126 gpm/ft{sup 2}. In both matrices, the filtrate flux appeared to be proportional to axial velocity, and the permeability appeared to be inversely proportional to the trans-membrane pressure. The first test condition was repeated as the last test condition for each matrix. In both cases, there was a significant decrease in filtrate flux, indicating some filter fouling during the test matrix that could not be removed by backpulsing alone, although the backpulse number and duration were not optimized. Following testing of these two matrices, the material was washed within the CUF by

  6. 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.

  7. Cake creep during filtration of flocculated manure

    DEFF Research Database (Denmark)

    Christensen, Morten Lykkegaard; Keiding, Kristian

    the distribution of N and P on the fields. Filtration is a useful method for such a separation. Furthermore, chemicals can be added to flocculate the solids and thereby increase the filterability i.e. the specific filter-cake resistance can be reduced from 1015 m/kg to 1011 m/kg. Both the amount of added chemicals......, and the mixing procedure affect the result, and lab-scale experiments are often used to study how these pre-treatments influence the filtration process. However, the existing mathematical filtration models are based on filtration of inorganic particles and cannot simulate the filtration data obtained when manure...... that the discrepancy between the filtration theory and the observed filtration behaviour is due to a time-dependent collapse of the formed cake (creep). This can also explain the observed behaviour when flocculated manure is filtered. The filtration data can be simulated if cake creep is adopted in the filtration...

  8. Enhancement of fine particle filtration with efficient humidification☆

    Institute of Scientific and Technical Information of China (English)

    Yumei Zhang; Weidong Zhang; Zhengyu Yang; Junteng Liu; Fushen Yang; Ning Li; Le Du⁎

    2016-01-01

    Filtration is one of the most effective methods to remove suspended fine particles from air. In filtration processes, pressure drop of compact dust cake causes problems in efficiency and economy, which has received increasing at-tention and stil remains chal enging. In this study, we developed a novel technique to intensify the filtration of fine particles with efficient humidification. Two strategies for humidification, including ultrasonic atomization and steam humidification (control ing of ambient humidity), were employed and proved to be both effective. The re-generation frequency of the filter could be reduced by 55%with ultrasonic atomization, while steam humidification could lead to a 78%reduction in regeneration frequency. The effect of operating conditions on pressure drop and the mass loading during filtration were investigated. The dust cake showed a loose and porous structure with an opti-mized droplet-to-particle ratio. With the ratio of 1.53 and 0.0282, the maximum mass loading was 552 g·m−2 upon the ultrasonic atomization and 720 g·m−2 upon the steam humidification. The results show that humidification could slow down the increase of pressure drop during filtration and improve the efficiency of process.

  9. Air movement and perceived air quality

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor; Kaczmarczyk, J.

    2012-01-01

    The impact of air movement on perceived air quality (PAQ) and sick building syndrome (SBS) symptoms was studied. In total, 124 human subjects participated in four series of experiments performed in climate chambers at different combinations of room air temperature (20, 23, 26 and 28 °C), relative...... humidity (30, 40 and 70%) and pollution level (low and high). Most of the experiments were performed with and without facially applied airflow at elevated velocity. The importance of the use of recirculated room air and clean, cool and dry outdoor air was studied. The exposures ranged from 60. min to 235....... min. Acceptability of PAQ and freshness of the air improved when air movement was applied. The elevated air movement diminished the negative impact of increased air temperature, relative humidity and pollution level on PAQ. The degree of improvement depended on the pollution level, the temperature...

  10. Effect of flue gas recirculation on heat transfer in a supercritical circulating fluidized bed combustor

    Science.gov (United States)

    Błaszczuk, Artur

    2015-09-01

    This paper focuses on assessment of the effect of flue gas recirculation (FGR) on heat transfer behavior in 1296t/h supercritical coal-fired circulating fluidized bed (CFB) combustor. The performance test in supercritical CFB combustor with capacity 966 MWth was performed with the low level of flue gas recirculation rate 6.9% into furnace chamber, for 80% unit load at the bed pressure of 7.7 kPa and the ratio of secondary air to the primary air SA/PA = 0.33. Heat transfer behavior in a supercritical CFB furnace between the active heat transfer surfaces (membrane wall and superheater) and bed material has been analyzed for Geldart B particle with Sauter mean diameters of 0.219 and 0.246 mm. Bed material used in the heat transfer experiments had particle density of 2700 kg/m3. A mechanistic heat transfer model based on cluster renewal approach was used in this work. A heat transfer analysis of CFB combustion system with detailed consideration of bed-to-wall heat transfer coefficient distributions along furnace height is investigated. Heat transfer data for FGR test were compared with the data obtained for representative conditions without recycled flue gases back to the furnace through star-up burners.

  11. Experimental Gasification of Biomass in an Updraft Gasifier with External Recirculation of Pyrolysis Gases

    Directory of Open Access Journals (Sweden)

    Adi Surjosatyo

    2014-01-01

    Full Text Available The updraft gasifier is a simple type of reactor for the gasification of biomass that is easy to operate and has high conversion efficiency, although it produces high levels of tar. This study attempts to observe the performance of a modified updraft gasifier. A modified updraft gasifier that recirculates the pyrolysis gases from drying zone back to the combustion zone and gas outlet at reduction zone was used. In this study, the level of pyrolysis gases that returned to the combustion zone was varied, and as well as measurements of gas composition, lower heating value and tar content. The results showed that an increase in the amount of pyrolysis gases that returned to the combustion zone resulted in a decrease in the amount of tar produced. An increase in the amount of recirculated gases tended to increase the concentrations of H2 and CH4 and reduce the concentration of CO with the primary (gasification air flow held constant. Increasing the primary air flow tended to increase the amount of CO and decrease the amount of H2. The maximum of lower heating value was 4.9 MJ/m3.

  12. Effect of flue gas recirculation on heat transfer in a supercritical circulating fluidized bed combustor

    Directory of Open Access Journals (Sweden)

    Błaszczuk Artur

    2015-09-01

    Full Text Available This paper focuses on assessment of the effect of flue gas recirculation (FGR on heat transfer behavior in 1296t/h supercritical coal-fired circulating fluidized bed (CFB combustor. The performance test in supercritical CFB combustor with capacity 966 MWth was performed with the low level of flue gas recirculation rate 6.9% into furnace chamber, for 80% unit load at the bed pressure of 7.7 kPa and the ratio of secondary air to the primary air SA/PA = 0.33. Heat transfer behavior in a supercritical CFB furnace between the active heat transfer surfaces (membrane wall and superheater and bed material has been analyzed for Geldart B particle with Sauter mean diameters of 0.219 and 0.246 mm. Bed material used in the heat transfer experiments had particle density of 2700 kg/m3. A mechanistic heat transfer model based on cluster renewal approach was used in this work. A heat transfer analysis of CFB combustion system with detailed consideration of bed-to-wall heat transfer coefficient distributions along furnace height is investigated. Heat transfer data for FGR test were compared with the data obtained for representative conditions without recycled flue gases back to the furnace through star-up burners.

  13. Influence of leachate recirculation on aerobic and anaerobic decomposition of solid wastes

    Energy Technology Data Exchange (ETDEWEB)

    Bilgili, M. Sinan [Yildiz Technical University, Environmental Engineering Department, 34349 Besiktas, Istanbul (Turkey)]. E-mail: mbilgili@yildiz.edu.tr; Demir, Ahmet [Yildiz Technical University, Environmental Engineering Department, 34349 Besiktas, Istanbul (Turkey)]. E-mail: ahmetd@yildiz.edu.tr; Ozkaya, Bestamin [Yildiz Technical University, Environmental Engineering Department, 34349 Besiktas, Istanbul (Turkey)]. E-mail: bozkaya@yildiz.edu.tr

    2007-05-08

    In this study, the effect of leachate recirculation on aerobic and anaerobic degradation of municipal solid wastes is determined by four laboratory-scale landfill reactors. The options studied and compared with the traditional anaerobic landfill are: leachate recirculation, landfill aeration, and aeration with leachate recirculation. Leachate quality is regularly monitored by the means of pH, alkalinity, total dissolved solids, conductivity, oxidation-reduction potential, chloride, chemical oxygen demand, ammonia, and total Kjeldahl nitrogen, in addition to generated leachate quantity. Aerobic leachate recirculated landfill appears to be the most effective option in the removal of organic matter and ammonia. The main difference between aerobic recirculated and non-recirculated landfill options is determined at leachate quantity. Recirculation is more effective on anaerobic degradation of solid waste than aerobic degradation. Further studies are going on to determine the optimum operational conditions for aeration and leachate recirculation rates, also with the operational costs of aeration and recirculation.

  14. Filtration combustion: Smoldering and SHS

    Science.gov (United States)

    Matkowsky, Bernard J.

    1995-01-01

    Smolder waves and SHS (self-propagating high-temperature synthesis) waves are both examples of combustion waves propagating in porous media. When delivery of reactants through the pores to the reaction site is an important aspect of the process, it is referred to as filtration combustion. The two types of filtration combustion have a similar mathematical formulation, describing the ignition, propagation and extinction of combustion waves in porous media. The goal in each case, however, is different. In smoldering the desired goal is to prevent propagation, whereas in SHS the goal is to insure propagation of the combustion wave, leading to the synthesis of desired products. In addition, the scales in the two areas of application may well differ. For example, smoldering generally occurs at a relatively low temperature and with a smaller propagation velocity than SHS filtration combustion waves. Nevertheless, the two areas of application have much in common, so that mechanisms learned about in one application can be used to advantage in the other. In this paper we discuss recent results in the areas of filtration combustion.

  15. Demonstration of creep during filtration

    DEFF Research Database (Denmark)

    Christensen, Morten Lykkegaard; Bugge, Thomas Vistisen; Kirchheiner, Anders Løvenbalk

    The classical filtration theory assumes a unique relationship between the local filter cake porosity and the local effective pressure. For a number of compressible materials, it has however been observed that during the consolidation stage this may not be the case. It has been found that the prod......The classical filtration theory assumes a unique relationship between the local filter cake porosity and the local effective pressure. For a number of compressible materials, it has however been observed that during the consolidation stage this may not be the case. It has been found...... that the production of filtrate also depends on the characteristic time for the filter cake solids to deform. This is formulated in the Terzaghi-Voigt model in which a secondary consolidation is introduced. The secondary consolidation may be visualized by plots of the relative cake deformation (U) v.s. the square...... magnitude as the primary consolidation (defined by the hydraulic retardation), the creep phenomenon may occur during filtration. This will lead to Ruth's plots characterized by a concave with two (more or less) distinct slopes. The slopes are defined by the relationship between the porosity...

  16. Superamphiphobic nanofibrous membranes for effective filtration of fine particles.

    Science.gov (United States)

    Wang, Na; Zhu, Zhigao; Sheng, Junlu; Al-Deyab, Salem S; Yu, Jianyong; Ding, Bin

    2014-08-15

    The worldwide demands are rising for an energy-efficient and cost-effective approach that can provide advanced nanofibrous membranes with high filtration performance and superior antifouling properties. Here we report a novel synthesized fluorinated polyurethane (FPU) modified nanofibrous membrane optimized to achieve oil and non-oil aerosol particle filtration. By employing the FPU incorporation, the polyacrylonitrile/polyurethane (PAN/PU) composite membranes were endowed with superhydrophobicity with a water contact angle of 154° and superoleophobicity with an oil contact angle of 151°. Morphology, surface wettability, porous structure, and filtration performance could be manipulated by tuning the solution composition as well as the hierarchical structure. Furthermore, the as-prepared membranes can capture, for the first time, a range of different oil aerosol particles in a single-unit operation, with >99.9% filtration efficiency, by using the combined contribution of fiber diameter and surface roughness acting on the objective particles. Exemplified here by the construction of superamphiphobic nanofibrous membrane, numerous applications of this medium includes high efficiency particulate air filters, ultra-low penetration air filters, and respiratory protection equipment.

  17. Derivation of total filtration thickness for diagnostic x-ray source assembly

    Science.gov (United States)

    Sekimoto, Michiharu; Katoh, Yoh

    2016-08-01

    The method defined by the IEC 60522 for determining the inherent filtration of an x-ray source device is applicable only for a limited range of tube voltage. Because the users cannot legally remove the x-ray movable diaphragm of the x-ray source device, total filtration, which is the sum of the additional filtration diaphragm movable for specific filtration and x-ray, cannot be measured. We develop a method for simply obtaining the total filtration for different tube voltage values. Total filtration can be estimated from a ratio R‧ of the air kerma Kx+T\\prime , which is measured with an Al plate with thickness T, and Kx\\prime measured without an Al plate. The conditions of the target material of the x-ray source device are then entered into the Report 78 Spectrum Processor to calculate the air kerma K x and K x+T for Al thicknesses x and (x  +  T), respectively, to obtain R. The minimum value of x, which is the difference between the R and R‧, is the total filtration of the x-ray source device. The total filtration calculated using the industrial x-ray source device was within  ±1% in the 40-120 kV range. This method can calculate the total filtration using air kerma measurements with and without the Al plate. Therefore, the load on the x-ray tube can be reduced, and preparation of multiple Al plates is not necessary. Furthermore, for the 40-120 kV tube voltage range, the user can easily measure the total filtration.

  18. Experimental investigation of reactive turbulent recirculating jet mixing in a dump

    Science.gov (United States)

    Smith, G. D.; Giel, T. V.; Catalano, C. G.

    1980-01-01

    A ducted, subsonic, hydrogen air turbulent jet mixing flowfield was investigated, both with and without combustion. The geometric configuration was representative of a sudden expansion or dump combustor, with a central air jet surrounded by a low velocity hydrogen stream at an overall equivalence ratio of 0.12. The ratio of the duct to inner nozzle diameter was 2.5. Radial distributions of mean axial and radial velocity, axial and radial turbulent intensity, velocity cross correlation, gas composition, static temperature and total pressure, as well as axial distributions of wall static pressure, were obtained for axial stations from zero to six duct diameters from the combustor entrance. The data indicate that mixing is slower in the chemically reactive flow field than in the nonreactive flow field, and that the presence of combustion has a significant effect on the size and location of the recirculation zone within the mixing duct.

  19. Filtration Understanding: FY10 Testing Results and Filtration Model Update

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, Richard C.; Billing, Justin M.; Burns, Carolyn A.; Peterson, Reid A.; Russell, Renee L.; Schonewill, Philip P.; Shimskey, Rick W.

    2011-04-04

    This document completes the requirements of Milestone 2-4, Final Report of FY10 Testing, discussed in the scope of work outlined in the EM31 task plan WP-2.3.6-2010-1. The focus of task WP 2.3.6 is to improve the U.S. Department of Energy’s (DOE’s) understanding of filtration operations for high-level waste (HLW) to improve filtration and cleaning efficiencies, thereby increasing process throughput and reducing the Na demand (through acid neutralization). Developing the cleaning/backpulsing requirements will produce much more efficient operations for both the Hanford Tank Waste Treatment and Immobilization Plant (WTP) and the Savannah River Site (SRS), thereby significantly increasing throughput by limiting cleaning cycles. The scope of this work is to develop the understanding of filter fouling to allow developing this cleaning/backpulsing strategy.

  20. Acceleration schedules for a recirculating heavy-ion accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, W.M.; Grote, D.P.

    2002-05-01

    Recent advances in solid-state switches have made it feasible to design programmable, high-repetition-rate pulsers for induction accelerators. These switches could lower the cost of recirculating induction accelerators, such as the ''small recirculator'' at Lawrence Livermore National Laboratory (LLNL), by substantially reducing the number of induction modules. Numerical work is reported here to determine what effects the use of fewer pulsers at higher voltage would have on the beam quality of the LLNL small recirculator. Lattices with different numbers of pulsers are examined using the fluid/envelope code CIRCE, and several schedules for acceleration and compression are compared for each configuration. For selected schedules, the phase-space dynamics is also studied using the particle-in-cell code WARP3d.

  1. Particle surface area and bacterial activity in recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Pedersen, Per Bovbjerg; von Ahnen, Mathis; Fernandes, Paulo

    2017-01-01

    Suspended particles in recirculating aquaculture systems (RAS) provide surface area that can be colonized by bacteria. More particles accumulate as the intensity of recirculation increases thus potentially increasing the bacterial carrying capacity of the systems. Applying a recent, rapid, culture......-independent fluorometric detection method (Bactiquant®) for measuring bacterial activity, the current study explored the relationship between total particle surface area (TSA, derived from the size distribution of particles >5 μm) and bacterial activity in freshwater RAS operated at increasing intensity of recirculation......-up water; corresponding to 0.32 m3 make-up water kg−1 feed). This was likely due to the accumulation of dissolved nutrients sustaining free-living bacterial populations, and/or accumulation of suspended colloids and fine particles less than 5 μm in diameter, which were not characterized in the study...

  2. 40 CFR 141.173 - Filtration.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Filtration. 141.173 Section 141.173... PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration and Disinfection-Systems Serving 10,000 or More People § 141.173 Filtration. A public water system subject to the requirements of this subpart that...

  3. Use Recirculator "SALO" in the Mode of the Neutron Source

    CERN Document Server

    Guk, Ivan S; Dovbnya, Anatoly N; Kononenko, Stanislav; Peev, Fedor; Tarasenko, Alexander; Van der Wiel, Marnix

    2005-01-01

    The opportunity of use developed in NSC KIPT recirculator SALO* with superconducting accelerating structure TESLA for reception of intensive neutron streams surveyed. As an injector it is supposed to use RF-gun with superconducting accelerating structure. An electron beam with the peak energy 130 ??? is transported on a target located apart of 100 m from recirculator. System of the focusing are designed allowing to gain on a target the required density of a beam. Tolerances on precision of an alignment of magnetooptical devices are calculated.

  4. Efficiency enhancement in gasoline reforming through the recirculation of reformate

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, J. [DaimlerChrysler AG, RBP/AS, 89081 Ulm (Germany); Sommer, M. [DaimlerChrysler AG, RTC/A, 70567 Stuttgart (Germany); Diezinger, S.; Trimis, D.; Durst, F. [FAU Erlangen-Nurnberg, LSTM, 91031 Erlangen (Germany)

    2006-03-21

    Fuel processors for on-board hydrogen production have to meet numerous technical demands. They should be efficient, compact and lightweight, capable of different loads and able to perform cold start ups. In this paper, the recirculation of reformate is proposed as a means of efficiency enhancement. Different system configurations based on this idea are introduced and simulated. The resulting effect on the system's efficiency, the water balance as well as the impact of recirculation on the system's volume and weight are discussed. (author)

  5. A recirculating cooling system for improved topical cardiac hypothermia.

    Science.gov (United States)

    Rosenfeldt, F L; Fambiatos, A; Pastoriza-Pinol, J; Stirling, G R

    1981-10-01

    A simple system is described that recirculates cooling fluid for topical cardiac hypothermia. This disposable system can produce a flow of 1,500 ml/min at 2 degrees to 4 degrees C. The recirculating cooler produced significantly lower myocardial temperatures than a conventional fluid-discard system in 22 patients having coronary operation. This system has been used as part of the technique of hypothermic cardioplegia in more than 600 patients. During various cardiac procedures, septal temperatures were maintained well below 20 degrees C for 60 minutes or more without the need to reinfuse the cardioplegic solution.

  6. Comparison of nonwoven fiberglass and stainless steel microfiber media in aerosol coalescence filtration

    Science.gov (United States)

    Manzo, Gabriel

    Coalescing filters are used to remove small liquid droplets from air streams. They have numerous industrial applications including dehumidification, cabin air filtration, compressed air filtration, metal working, CCV, and agriculture. In compressed air systems, oils used for lubrication of compressor parts can aerosolize into the main air stream causing potential contamination concerns for downstream applications. In many systems, humid air can present problems to sensitive equipment and sensors. As the humid air cools, small water drops condense and can disrupt components that need to be kept dry. Fibrous nonwoven filter media are commonly used to coalesce small drops into larger drops for easier removal. The coalescing performance of a medium is dependent upon several parameters including permeability, porosity, and wettability. In many coalescing filters, glass fibers are used. In this work, the properties of steel fiber media are measured to see how these properties compare to glass fiber media. Steel fiber media has different permeability, porosity and wettability to oil and water than fiber glass media. These differences can impact coalescence performance. The impact of these differences in properties on coalescence filtration performance was evaluated in a coalescence test apparatus. The overall coalescence performance of the steel and glass nonwoven fiber media are compared using a filtration efficiency and filtration index. In many cases, the stainless steel media performed comparably to fiber glass media with efficiencies near 90%. Since stainless steel media had lower pressure drops than fiber glass media, its filtration index values were significantly higher. Broader impact of this work is the use of stainless steel fiber media as an alternative to fiber glass media in applications where aerosol filtration is needed to protect the environment or sensitive equipment and sensors.

  7. Evaluation of a Shaker Dust Collector for Use in a Recirculating Ventilation System.

    Science.gov (United States)

    Peters, Thomas M; Sawvel, Russell A; Park, Jae Hong; Anthony, T Renée

    2015-01-01

    General ventilation with recirculated air may be cost-effective to control the concentration of low-toxicity, contaminants in workplaces with diffuse, dusty operations, such as in agriculture. Such systems are, however, rarely adopted with little evidence showing improved air quality and ability to operate under harsh conditions. The goal of this work was to examine the initial and long-term performance of a fabric-filter shaker dust collector (SDC) in laboratory tests and as deployed within a recirculating ventilation system in an agricultural building. In laboratory tests, collection efficiency and pressure drop were tracked over several filter loading cycles, and the recovery of filter capacity (pressure drop) from filter shaking was examined. Collection efficiencies of particles larger than 5 μm was high (>95%) even when the filter was pristine, showing effective collection of large particles that dominate inhalable concentrations typical of agricultural dusts. For respirable-sized particles, collection efficiencies were low when the filter was pristine (e.g., 27% for 1 μm) but much higher when a dust cake developed on the filter (>99% for all size particles), even after shaking (e.g., 90% for 1 μm). The first shake of a filter was observed to recovery a substantial fraction of filter capacity, with subsequent shakes providing little benefit. In field tests, the SDC performed effectively over a period of three months in winter when incorporated in a recirculating ventilation system of a swine farrowing room. Trends in collection efficiency and pressure drop with loading were similar to those observed in the laboratory with overall collection efficiencies high (>80%) when pressure drop exceeded 230 Pa, or 23% of the maximum loading recommended by the manufacturer. This work shows that the SDC can function effectively over the harsh winter in swine rearing operations. Together with findings of improved air quality in the farrowing room reported in a

  8. Mobile surface water filtration system

    Directory of Open Access Journals (Sweden)

    Aashish Vatsyayan

    2012-09-01

    Full Text Available To design a mobile system for surface water filtrationMethodology: the filtration of surface impurities begins with their retraction to concentrated thickness using non ionising surfactants, then isolation using surface tension property and sedimentation of impurities in process chamber using electrocoagulation. Result:following studies done to determine the rate of spreading of crude oil on water a method for retraction of spread crude oil to concentrated volumes is developed involving addition of non -ionising surfactants in contrast to use of dispersants. Electrocoagulation process involves multiple processes taking place to lead to depositionof impurities such as oil, grease, metals. Studies of experiments conducted reveals parameters necessary for design of electrocoagulation process chamber though a holistic approach towards system designing is still required. Propeller theory is used in determining the required design of propeller and the desired thrust, the overall structure will finally contribute in deciding the choice of propeller.

  9. Centrifugal membrane filtration -- Task 9

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-08-01

    The Energy and Environmental Research Center (EERC) has teamed with SpinTek Membrane Systems, Inc., the developer of a centrifugal membrane filtration technology, to demonstrate applications for the SpinTek technology within the US Department of Energy (DOE) Environmental management (EM) Program. The technology uses supported microporous membranes rotating at high rpm, under pressure, to separate suspended and colloidal solids from liquid streams, yielding a solids-free permeate stream and a highly concentrated solids stream. This is a crosscutting technology that falls under the Efficient Separations and Processing Crosscutting Program, with potential application to tank wastes, contaminated groundwater, landfill leachate, and secondary liquid waste streams from other remediation processes, including decontamination and decommissioning systems. Membrane-screening tests were performed with the SpinTek STC-X4 static test cell filtration unit, using five ceramic membranes with different pore size and composition. Based on permeate flux, a 0.25-{micro}m TiO{sub 2}/Al{sub 2}O{sub 3} membrane was selected for detailed performance evaluation using the SpinTek ST-IIL centrifugal membrane filtration unit with a surrogate tank waste solution. An extended test run of 100 hr performed on a surrogate tank waste solution showed some deterioration in filtration performance, based on flux, apparently due to the buildup of solids near the inner portion of the membrane where relative membrane velocities were low. Continued testing of the system will focus on modifications to the shear pattern across the entire membrane surface to affect improved long-term performance.

  10. Cake Filtration in Viscoelastic Polymer Solutions

    Science.gov (United States)

    Surý, Alexander; Machač, Ivan

    2009-07-01

    In this contribution, the filtration equations for a cake filtration in viscoelastic fluids are presented. They are based on a capillary hybrid model for the flow of a power law fluid. In order to express the elastic pressure drop excess in the flow of viscoelastic filtrate through the filter cake and filter screen, modified Deborah number correction functions are included into these equations. Their validity was examined experimentally. Filtration experiments with suspensions of hardened polystyrene particles (Krasten) in viscoelastic aqueous solutions of polyacryl amides (0.4% and 0.6%wt. Kerafloc) were carried out at a constant pressure on a cylindrical filtration unit using filter screens of different resistance.

  11. Anaerobic ammonium-oxidizing (anammox) bacteria and associated activity in fixed-film biofilters of a marine recirculating aquaculture system.

    Science.gov (United States)

    Tal, Yossi; Watts, Joy E M; Schreier, Harold J

    2006-04-01

    Microbial communities in the biological filter and waste sludge compartments of a marine recirculating aquaculture system were examined to determine the presence and activity of anaerobic ammonium-oxidizing (anammox) bacteria. Community DNA was extracted from aerobic and anaerobic fixed-film biofilters and the anaerobic sludge waste collection tank and was analyzed by amplifying 16S rRNA genes by PCR using anammox-selective and universal GC-clamped primers. Separation of amplified PCR products by denaturing gradient gel electrophoresis and sequencing of the different phylotypes revealed a diverse biofilter microbial community. While Planctomycetales were found in all three communities, the anaerobic denitrifying biofilters contained one clone that exhibited high levels of sequence similarity to known anammox bacteria. Fluorescence in situ hybridization studies using an anammox-specific probe confirmed the presence of anammox Planctomycetales in the microbial biofilm from the denitrifying biofilters, and anammox activity was observed in these biofilters, as detected by the ability to simultaneously consume ammonia and nitrite. To our knowledge, this is the first identification of anammox-related sequences in a marine recirculating aquaculture filtration system, and our findings provide a foundation for incorporating this important pathway for complete nitrogen removal in such systems.

  12. Improved zinc electrode and rechargeable zinc-air battery

    Science.gov (United States)

    Ross, P.N. Jr.

    1988-06-21

    The invention comprises an improved rechargeable zinc-air cell/battery having recirculating alkaline electrolyte and a zinc electrode comprising a porous foam support material which carries the active zinc electrode material. 5 figs.

  13. Understanding heat transfer in 2D channel flows including recirculation

    NARCIS (Netherlands)

    Dirkse, M.H.; Loon, van W.K.P.; Stigter, J.D.; Bot, G.P.A.

    2007-01-01

    Inviscid, irrotational two-dimensional flows can be modelled using the Schwarz¿Christoffel integral. Although bounded flows including boundary layer separation and recirculation are not irrotational, a model is presented that uses the Schwarz¿Christoffel integral to model these flows. The model sepa

  14. Numerical analysis and control of the recirculation bubble strength ...

    African Journals Online (AJOL)

    user

    So et al (1985) experimentally determined jet characteristics in confined swirling ... z r u effr rr z u eff z z p z u u r u v μ μ μ μ ρ. 1. 1. (2). Radial component ..... swirl number it is possible to prevent generation of recirculation bubble in the mixing.

  15. Constrained control of a once-through boiler with recirculation

    DEFF Research Database (Denmark)

    Trangbæk, K

    2008-01-01

    There is an increasing need to operate power plants at low load for longer periods of time. When a once-through boiler operates at a sufficiently low load, recirculation is introduced, significantly altering the control structure. This paper illustrates the possibilities for using constrained con...

  16. Microorganisms in recirculating aquaculture systems and their management

    NARCIS (Netherlands)

    Rurangwa, E.; Verdegem, M.C.J.

    2015-01-01

    Recirculation aquaculture systems (RASs) are increasingly considered as production systems of the future with a minimum ecological impact for the production of aquatic food. To maintain a good water quality and to produce quality and healthy fishery products, the systems depend on a diverse microbia

  17. Use of low temperature blowers for recirculation of hot gases

    Science.gov (United States)

    Maru, H.C.; Forooque, M.

    1982-08-19

    An apparatus is described for maintaining motors at low operating temperatures during recirculation of hot gases in fuel cell operations and chemical processes such as fluidized bed coal gasification. The apparatus includes a means for separating the hot process gas from the motor using a secondary lower temperature gas, thereby minimizing the temperature increase of the motor and associated accessories.

  18. The effect of flow recirculation on abdominal aortic aneurysm

    Science.gov (United States)

    Taib, Ishkrizat; Amirnordin, Shahrin Hisham; Madon, Rais Hanizam; Mustafa, Norrizal; Osman, Kahar

    2012-06-01

    The presences of flow recirculation at the abdominal aortic aneurysm (AAA) region yield the unpredictable failure of aneurismal wall. The failure of the aneurismal wall is closely related to the hemodynamic factor. Hemodynamic factor such as pressure and velocity distribution play a significance role of aneurysm growth and rupture. By using the computational approach, the influence of hemodynamic factor is investigated using computational fluid dynamic (CFD) method on the virtual AAA model. The virtual 3D AAAs model was reconstructed from Spiral Computed Tomography scan (CT-scan). The blood flow is assumed as being transient, laminar and Newtonian within a rigid section of the vessel. The blood flow also driven by an imposed of pressure gradient in the form of physiological waveform. The pulsating blood flow is also considered in this simulation. The results on pressure distribution and velocity profile are analyzed to interpret the behaviour of flow recirculation. The results show the forming of vortices is seen at the aneurysm bulge. This vortices is form at the aneurysm region then destroyed rapidly by flow recirculation. Flow recirculation is point out much higher at distal end of aneurysm closed to iliac bifurcation. This phenomenon is managed to increase the possibility of aneurysm growth and rupture.

  19. Design and development of desiccant seed dryer with airflow inversion and recirculation.

    Science.gov (United States)

    Gill, R S; Singh, Sukhmeet; Singh, Parm Pal

    2014-11-01

    A desiccant seed dryer has been developed to dry seed in deep bed at safe temperatures for good shelf life and germination. The dryer consists of two chambers viz., air conditioning control unit and seed drying chamber. It operates in seed drying mode and desiccant regeneration mode. It has provision for recirculation of the drying air to minimise the moisture removal from drying air. Also, it has provision of airflow inversion through deep seed bed for uniform drying. Moisture removal from drying air has been done using silica gel desiccant. Chilly 'Punjab Surakh', Chilly 'Punjab Guchhedaar', Paddy, Coriander, Fenugreek and Radish seeds was dried with hot air at 38 °C from initial moisture content of 26.9 to 5 % (wb) in 2 h, 46.52 to 4.19 % (wb) in 4.25 h, 13.3 to 2.61 % (wb) in 4 h, 13.4 to 10.08 % (wb) in 3 h, 12.4 to 8.22 % (wb) in 4¼ h and 10.6 to 6.08 % (wb) in 4 h respectively. The statistical analysis based on paired t-test showed that seed drying in this dryer has no adverse effect on seed germination.

  20. Impact assessment of concentrate recirculation on the landfill gas production

    Directory of Open Access Journals (Sweden)

    Džolev Nikola M.

    2016-01-01

    Full Text Available This paper explores the impact of concentrate recirculation, as a product of leachate treated by reverse osmosis plant, on the production of landfill gas at the real-scale landfill for municipal solid waste. In an effort to come up with results experimental measurements were carried out at the landfill in Bijeljina. All measurements performed, were divided into 3 groups. The aims of two groups of measurement were to determine landfill gas and methane yield from concentrate and leachate in laboratory conditions (1st group and to find out concentrations of oxidizing matters (COD and BOD5 present in leachate and concentrate at different points of treatment as well as its variability over the time (2nd group which could be used to calculate the potential of landfill gas and methane generation from concentrate by recirculation, theoretically. 3rd group of measurements, carried out in parallel, have goal to determine the quality and quantity of the collected landfill gas at wells throughout the landfill. The results of analysis carried out in this experimental research show the clear evidence of concentrate recirculation impact on methane production by increasing the landfill gas flow, as well as its concentration within the landfill gas composition, at the nearby well. Although results indicated relatively high impact of concentrate recirculation on landfill gas production, comparing to its theoretical potential, the influence on the landfill at whole, is negligible, due to relatively low volumes in recirculation with respect to its size and objectively low potential given by organic matter present in concentrate.

  1. Air quality. How to give it back its original purity? The proliferation of air cleansers. Filters must be changed regularly. Measurement of the filtering efficiency of air treatment systems. The air treatment plants on the way of certification. Essential oils in a high building; Qualite de l'air. Comment lui rendre sa purete originelle? La proliferation des purificateurs d'air. Il faut changer les filtres regulierement. Mesure de l'efficacite de filtration des systemes de traitement d'air. Les centrales de traitement d'air sur la voie de la certification. Des huiles essentielles dans un immeuble de grande hauteur

    Energy Technology Data Exchange (ETDEWEB)

    Grumel, N.

    2000-07-01

    Outside air is polluted while the ambient indoor air is saturated with microorganisms. Inside buildings, the aeraulic networks are the link between both environments and the privileged place to clean the air using filtering systems. However, the notion of air quality is still badly perceived by owners, in particular in tertiary buildings. In France, efforts have to be made on the maintenance of aeraulic networks by hygiene specialists. Air quality inside buildings must be taken into consideration using communication and regulations. This dossier takes stock of the problem of air quality and of the available means to ensure a good air quality inside residential and tertiary buildings. The maintenance of air filters in one of the key points. It should be integrated in the general maintenance concept of buildings. The dossier includes a study of the in-situ measurement of the filtering efficiency of air treatment systems. This method is described in the Eurovent recommendation 4/10 of 1996. It has been experimented by the French technical centre of aeraulic and thermal industries (Cetiat) and the results are reported in the study. The performances of air treatment plants are now certified by Eurovent. This European organization has defined a program of tests which is conformable with the European EN 1886 and EN 13053 European standards. Finally, a new protocol of air decontamination based on the micronizing of essential oils in the aeraulic network of a 29 floors building is presented. (J.S.)

  2. Formation of disinfection byproducts in a recirculating mariculture system: emerging concerns.

    Science.gov (United States)

    Qiang, Zhimin; Zhang, Haiting; Dong, Huiyu; Adams, Craig; Luan, Gang; Wang, Lei

    2015-02-01

    Disinfection is commonly employed in recirculating mariculture systems (RMS) to control animal diseases and improve seawater quality; however, little is known about the occurrence of disinfection byproducts (DBPs) formed in such RMS. Beijing Aquarium is a typical RMS with artificially prepared seawater and mainly adopts a decentralized treatment strategy for different animal tanks, including sand filtration, foam fractionation, and disinfection (O3, UV, and O3/ClO2). This study reveals that the adopted disinfection processes were highly effective in controlling marine heterotrophic bacteria; however, some concerns were raised on the formation of various kinds of DBPs, including secondary oxidants, inorganic oxyanions, and hazardous organic species. Free chlorine and free bromine were generated from ozonation at health-relevant concentrations. High concentrations of BrO3(-) and ClO3(-) were formed in mammal tanks, which exceeded the USEPA-regulated maximum contaminant level (MCL) for drinking water by 19-25 and 52-54 times, respectively. Extremely high concentrations of NO3(-) were detected in mammal tanks, which considerably exceeded the MCL regulated by the Sea Water Quality Standard of China for the mariculture industry (Class II) by about 1100 times. Undoubtedly, the presence of various DBPs poses serious health threats to aquarium animals. To solve these problems, potential control measures for DBPs are proposed.

  3. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT - BAGHOUSE FILTRATION PRODUCTS - W.L. GORE & ASSOCIATES, INC. L4347 FILTER SAMPLE

    Science.gov (United States)

    Baghouse filtration products (BFPs) were evaluated by the Air Pollution Control Technology (APCT) pilot of the Environmental Technology Verification (ETV) Program. The performance factor verified was the mean outlet particle concentration for the filter fabric as a function of th...

  4. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT - BAGHOUSE FILTRATION PRODUCTS - BASF CORPORATION AX/BA-14/9-SAXP FILTER SAMPLE

    Science.gov (United States)

    Baghouse filtration products (BFPs) were evaluated by the Air Pollution Control Technology (APCT) pilot of the Environmental Technology Verification (ETV) Program. The performance factor verified was the mean outlet particle concentration for the filter fabric as a function of th...

  5. Enzymatic Method for Rapid Determination of Oxalic Acid in Bleaching Filtrates from the Pulp and Paper Industry

    Institute of Scientific and Technical Information of China (English)

    HONG Feng; SJ(O)DE Anders; NILVEBRANT Nils-Olof; J(O)NSSON Leif J.

    2005-01-01

    Bleaching with oxygen-containing agents and recirculation of process streams in the pulp and paper industry has increased the accumulation of oxalic acid and danger for precipitation of calcium oxalate encrusts, scaling. Analysis and control of oxalic acid in bleaching filtrates is therefore becoming increasingly important in the pulp and paper industry.Chromatographic methods, such as IC and HPLC, are generally more time-consuming but are valuable as standard methods for determination of oxalic acid. However, the instrumentation needed is expensive and stationary. In this study, an enzymatic method based on oxalate oxidase and peroxidase was developed to determine oxalic acid in authentic bleaching filtrates using a spectrophotometer. The results showed that bleaching filtrates contain some compounds interfering with the enzymatic method.Pretreatment of the samples with activated charcoal was a successful approach for decreasing problems with interference. By using dilution followed by charcoal treatment, the results obtained from five bleaching filtrates with the colorimetric method correlated very well with those obtained using IC. This study offers a selective, fast and mobile analysis method to determine oxalic acid in bleaching filtrates from the pulp and paper industry. The convenient enzyme-based method improves the possibilities for control of critical oxalic acid concentrations in closed-loop bleaching streams.

  6. Water Filtration Using Plant Xylem

    CERN Document Server

    Lee, Jongho; Chambers, Valerie; Venkatesh, Varsha; Karnik, Rohit

    2013-01-01

    Effective point-of-use devices for providing safe drinking water are urgently needed to reduce the global burden of waterborne disease. Here we show that plant xylem from the sapwood of coniferous trees - a readily available, inexpensive, biodegradable, and disposable material - can remove bacteria from water by simple pressure-driven filtration. Approximately 3 cm3 of sapwood can filter water at the rate of several liters per day, sufficient to meet the clean drinking water needs of one person. The results demonstrate the potential of plant xylem to address the need for pathogen-free drinking water in developing countries and resource-limited settings.

  7. Pig manure treatment and purification by filtration.

    Science.gov (United States)

    Makara, A; Kowalski, Z

    2015-09-15

    This study aimed to develop a new, complex pig manure treatment and filtration process. The final scheme, called the AMAK process, comprised the following successive steps: mineralization with mineral acids, alkalization with lime milk, superphosphate addition, a second alkalization, thermal treatment, and pressure filtration. The proposed method produced a filtrate with 95%, 80%, and 96% reductions in chemical oxygen demand, nitrogen content, and phosphorus content, respectively. An advantage of the proposed method was that it incorporated a crystalline phase into the solid organic part of the manure, which enabled high filtration rates (>1000 kg m(-2) h(-1)) and efficient separation. The process also eliminated odor emissions from the filtrate and sediment. The treated filtrate could be used to irrigate crops or it could be further treated in conventional biological wastewater treatment plants. The sediment could be used for producing mineral-organic fertilizer. The AMAK process is inexpensive, and it requires low investment costs.

  8. Enhancement of centrifugal compressor stable operation using an internal recirculation channel

    Directory of Open Access Journals (Sweden)

    Růžička M.

    2016-12-01

    Full Text Available Centrifugal compressors with a high pressure ratio are widely used in small aircraft turbine engines and turbocharges. At high rotational speeds they have a narrow stable operating region and the commonly used impellers with back swept blades are not able to ensure requested stability. In order to achieve a wider stable operating region, some other anti-surge measures can be used such as an Internal Recirculation Channel (IRC located in the inlet area of the compressor impeller. This paper analyses the influence of various IRC inlet slot geometries on air flow parameters. The flow velocity profiles downstream of the IRC outlet slot are evaluated and the influence of various channel configurations on compressor performance map is shown. Results from experiments as well as CFD simulations enable us to analyse the airflow in IRC and find out its most suitable geometry.

  9. Experiments on the formation of a recirculation zone in swirling coaxial jets

    Science.gov (United States)

    Champagne, F. H.; Kromat, S.

    The near flow field of coaxial air jets, with swirl in the outer one, was studied using flow visualization and hot-wire anemometry. The flow is sensitive to both the swirl number and the mass flow ratio between the outer and inner jets. A necessary condition for the formation of an internal recirculation zone (IRZ) is that the swirl number must exceed a minimum value which depends on the mass flow ratio. Spectral analysis of the velocity fluctuations indicates that the formation of an IRZ in the present flow does not appear to be related to the growth of convective flow instabilities. Analysis of the flow visualization and X-wire data indicates that the vorticity dynamics model for vortex breakdown proposed by Brown and Lopez [J Fluid Mech (1990) 222: 553] provides a plausible mechanism for the formation of an IRZ in this flow.

  10. Carbon Nanotube Membranes: Synthesis, Properties, and Future Filtration Applications

    Science.gov (United States)

    Rashid, Md. Harun-Or; Ralph, Stephen F.

    2017-01-01

    Over the course of the past decade, there has been growing interest in the development of different types of membranes composed of carbon nanotubes (CNTs), including buckypapers and composite materials, for an ever-widening range of filtration applications. This article provides an overview of how different types of CNT membranes are prepared and the results obtained from investigations into their suitability for different applications. The latter involve the removal of small particles from air samples, the filtration of aqueous solutions containing organic compounds and/or bacteria, and the separation of individual liquids present in mixtures. A growing number of reports have demonstrated that the incorporation of CNTs into composite membranes confers an improved resistance to fouling caused by biomacromolecules and bacteria. These results are discussed, along with evidence that demonstrates it is possible to further reduce fouling by taking advantage of the inherent conductivity of composite membranes containing CNTs, as well as by using different types of electrochemical stimuli. PMID:28468314

  11. NASA Lunar Dust Filtration and Separations Workshop Report

    Science.gov (United States)

    Agui, Juan H.; Stocker, Dennis P.

    2009-01-01

    NASA Glenn Research Center hosted a 2.5-day workshop, entitled "NASA Lunar Dust Filtration and Separations Workshop" at the Ohio Aerospace Institute in Cleveland, Ohio, on November 18 to 20, 2008. The purpose of the workshop was to address the issues and challenges of particulate matter removal from the cabin atmospheres in the Altair lunar lander, lunar habitats, and in pressurized rovers. The presence of lunar regolith dust inside the pressurized volumes was a theme of particular interest. The workshop provided an opportunity for NASA, industry experts, and academia to identify and discuss the capabilities of current and developing air and gas particulate matter filtration and separations technologies as they may apply to NASA s needs. A goal of the workshop was to provide recommendations for strategic research areas in cabin atmospheric particulate matter removal and disposal technologies that will advance and/or supplement the baseline approach for these future lunar surface exploration missions.

  12. Side Stream Filtration for Cooling Towers

    Energy Technology Data Exchange (ETDEWEB)

    None

    2012-10-20

    This technology evaluation assesses side stream filtration options for cooling towers, with an objective to assess key attributes that optimize energy and water savings along with providing information on specific technology and implementation options. This information can be used to assist Federal sites to determine which options may be most appropriate for their applications. This evaluation provides an overview of the characterization of side stream filtration technology, describes typical applications, and details specific types of filtration technology.

  13. Glomerular Filtration Barrier Assembly: An insight

    OpenAIRE

    Arif, Ehtesham; Nihalani, Deepak

    2013-01-01

    A glomerulus is the network of capillaries that resides in the Bowman’s capsule that functions as a filtration unit of kidney. The glomerular function ensures that essential plasma proteins are retained in blood and the filtrate is passed on as urine. The glomerular filtration assembly is composed of three main cellular barriers that are critical for the ultrafiltration process, the fenestrated endothelium, glomerular basement membrane and highly specialized podocytes. The podocytes along wit...

  14. Persistent homology in graph power filtrations.

    Science.gov (United States)

    Parks, Allen D; Marchette, David J

    2016-10-01

    The persistence of homological features in simplicial complex representations of big datasets in R (n) resulting from Vietoris-Rips or Čech filtrations is commonly used to probe the topological structure of such datasets. In this paper, the notion of homological persistence in simplicial complexes obtained from power filtrations of graphs is introduced. Specifically, the rth complex, r ≥ 1, in such a power filtration is the clique complex of the rth power G(r) of a simple graph G. Because the graph distance in G is the relevant proximity parameter, unlike a Euclidean filtration of a dataset where regional scale differences can be an issue, persistence in power filtrations provides a scale-free insight into the topology of G. It is shown that for a power filtration of G, the girth of G defines an r range over which the homology of the complexes in the filtration are guaranteed to persist in all dimensions. The role of chordal graphs as trivial homology delimiters in power filtrations is also discussed and the related notions of 'persistent triviality', 'transient noise' and 'persistent periodicity' in power filtrations are introduced.

  15. Filtration and compression of organic materials

    DEFF Research Database (Denmark)

    Christensen, Morten Lykkegaard; Keiding, Kristian

    The conventional filtration theory has been based on filtrations of incompressible particles such as anatase, kaolin and clay. The filtration models have later been used for organic slurries but can often not explain the observed experimental data. At constant pressure, the filtrate volume does...... not increase in proportion with square root time when e.g. sewage sludge and manure are filtered. Different explanations have been suggested. However, organic slurries are complex mixtures and it is therefore difficult to evaluate the suggested explanations and develops new models. One possible solution...

  16. Energy Analysis of n-Dodecane Combustion in a Hetero/Homogeneous Heat-Recirculating Microreactor for Portable Power Applications

    Science.gov (United States)

    Waits, C. M.; Tolmachoff, E. D.; Allmon, W. R.; Zecher-Freeman, N. E.

    2016-11-01

    An energy analysis is presented for n-dodecane/air combustion in a heat recirculating Inconel microreactor under vacuum conditions. Microreactor channels are partially coated with platinum enabling operating with coupled heterogeneous and homogeneous reactions. The radiant efficiency, important for thermophotovoltaic energy conversion, was found to decrease from 57% to 52% over 5 different runs covering 377 min of operation. A similar decrease in combustion efficiency was observed with 6%-8% energy lost to incomplete combustion and 5%- 6% lost through sensible heat in the exhaust. The remaining thermal loss is from unusable radiation and conduction through inlet and outlet tubing. Changes in the Inconel microreactor geometry and emissivity properties were observed.

  17. Tracking studies in eRHIC energy-recovery recirculator

    Energy Technology Data Exchange (ETDEWEB)

    Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Brooks, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ptitsyn, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Trbojevic, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tsoupas, N. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-07-13

    Beam and polarization tracking studies in eRHIC energy recovery electron recirculator are presented, based on a very preliminary design of the FFAG lattice. These simulations provide examples of some of the beam and spin optics aspects of the linear FFAG lattice concept and its application in eRHIC, they provide code benchmarking for synchrotron radiation and spin diffusion in addition, and pave the way towards end-to-end 6-D(phasespace)+3D(spin) tracking simulations.

  18. Control of synchrotron radiation effects during recirculation with bunch compression

    Energy Technology Data Exchange (ETDEWEB)

    Douglas, David [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Benson, Stephen [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Li, Rui [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Roblin, Yves [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Tennant, Christopher [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Krafft, Geoffrey [Old Dominion Univ., Norfolk, VA (United States); Terzic, Balsa [Old Dominion Univ., Norfolk, VA (United States); Tsai, Cheng [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

    2015-05-01

    Studies of beam quality during recirculation have been extended to an arc providing bunch compression with positive momentum compaction. It controls both incoherent and coherent synchrotron radiation (ISR and CSR) using methods including optics balance and generates little microbunching gain. We detail the dynamical basis for the design, discuss the design process, give an example, and provide simulations of ISR and CSR effects. Reference will be made to a complete analysis of microbunching effects.

  19. Mathematical model for analysis of recirculating vertical flow constructed wetlands.

    Science.gov (United States)

    Sklarz, Menachem Y; Gross, Amit; Soares, M Ines M; Yakirevich, Alexander

    2010-03-01

    The recirculating vertical flow constructed wetland (RVFCW) was developed for the treatment of domestic wastewater (DWW). In this system, DWW is applied to a vertical flow bed through which it trickles into a reservoir located beneath the bed. It is then recirculated back to the root zone of the bed. In this study, a compartmental model was developed to simulate the RVFCW. The model, which addresses transport and removal kinetics of total suspended solids, 5-day biological oxygen demand and nitrogen, was fitted to kinetical results obtained from pilot field setups and a local sensitivity analysis was performed on the model parameters and operational conditions. This analysis showed that after 5h of treatment water quality is affected more by stochastic events than by the model parameter values, emphasizing the stability of the RVFCW system to large variations in operational conditions. Effluent quality after 1h of treatment, when the sensitivity analysis showed the parameter impacts to be largest, was compared to model predictions. The removal rate was found to be dependent on the recirculation rate. The predictions correlated well with experimental observations, leading to the conclusion that the proposed model is a satisfactory tool for studying RVFCWs. Copyright 2009 Elsevier Ltd. All rights reserved.

  20. Can combining economizers with improved filtration save energy and protect equipment in data centers?

    Energy Technology Data Exchange (ETDEWEB)

    Shehabi, Arman; Ganguly, Srirupa; Gundel, Lara A.; Horvath, Arpad; Kirchstetter, Thomas W.; Lunden, Melissa M.; Tschudi, William; Gadgil, Ashok J.; Nazaroff, William W

    2009-06-05

    Economizer use in data centers is an energy efficiency strategy that could significantly limit electricity demand in this rapidly growing economic sector. Widespread economizer implementation, however, has been hindered by potential equipment reliability concerns associated with exposing information technology equipment to particulate matter of outdoor origin. This study explores the feasibility of using economizers in data centers to save energy while controlling particle concentrations with high-quality air filtration. Physical and chemical properties of indoor and outdoor particles were analyzed at an operating northern California data center equipped with an economizer under varying levels of air filtration efficiency. Results show that when improved filtration is used in combination with an economizer, the indoor/outdoor concentration ratios for most measured particle types were similar to levels when using conventional filtration without economizers. An energy analysis of the data center reveals that, even during the summer months, chiller savings from economizer use greatly outweigh any increase in fan power associated with improved filtration. These findings indicate that economizer use combined with improved filtration could reduce data center energy demand while providing a level of protection from particles of outdoor origin similar to that observed with conventional design.

  1. Can combining economizers with improved filtration save energy and protect equipment in data centers?

    Energy Technology Data Exchange (ETDEWEB)

    Shehabi, Arman; Ganguly, Srirupa; Gundel, Lara A.; Horvath, Arpad; Kirchstetter, Thomas W.; Lunden, Melissa M.; Tschudi, William; Gadgil, Ashok J.; Nazaroff, William W

    2009-06-05

    Economizer use in data centers is an energy efficiency strategy that could significantly limit electricity demand in this rapidly growing economic sector. Widespread economizer implementation, however, has been hindered by potential equipment reliability concerns associated with exposing information technology equipment to particulate matter of outdoor origin. This study explores the feasibility of using economizers in data centers to save energy while controlling particle concentrations with high-quality air filtration. Physical and chemical properties of indoor and outdoor particles were analyzed at an operating northern California data center equipped with an economizer under varying levels of air filtration efficiency. Results show that when improved filtration is used in combination with an economizer, the indoor/outdoor concentration ratios for most measured particle types were similar to levels when using conventional filtration without economizers. An energy analysis of the data center reveals that, even during the summer months, chiller savings from economizer use greatly outweigh any increase in fan power associated with improved filtration. These findings indicate that economizer use combined with improved filtration could reduce data center energy demand while providing a level of protection from particles of outdoor origin similar to that observed with conventional design.

  2. Tangential flow filtration of hemoglobin.

    Science.gov (United States)

    Palmer, Andre F; Sun, Guoyong; Harris, David R

    2009-01-01

    Bovine and human hemoglobin (bHb and hHb, respectively) was purified from bovine and human red blood cells via tangential flow filtration (TFF) in four successive stages. TFF is a fast and simple method to purify Hb from RBCs using filtration through hollow fiber (HF) membranes. Most of the Hb was retained in stage III (100 kDa HF membrane) and displayed methemoglobin levels less than 1%, yielding final concentrations of 318 and 300 mg/mL for bHb and hHb, respectively. Purified Hb exhibited much lower endotoxin levels than their respective RBCs. The purity of Hb was initially assessed via SDS-PAGE, and showed tiny impurity bands for the stage III retentate. The oxygen affinity (P(50)) and cooperativity coefficient (n) were regressed from the measured oxygen-RBC/Hb equilibrium curves of RBCs and purified Hb. These results suggest that TFF yielded oxygen affinities of bHb and hHb that are comparable to values in the literature. LC-MS was used to measure the molecular weight of the alpha (alpha) and beta (beta) globin chains of purified Hb. No impurity peaks were present in the HPLC chromatograms of purified Hb. The mass of the molecular ions corresponding to the alpha and beta globin chains agreed well with the calculated theoretical mass of the alpha- and beta- globin chains. Taken together, our results demonstrate that HPLC-grade Hb can be generated via TFF. In general, this method can be more broadly applied to purify Hb from any source of RBCs. This work is significant, since it outlines a simple method for generating Hb for synthesis and/or formulation of Hb-based oxygen carriers.

  3. Investigation of Microbunching Instabilities in Modern Recirculating Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Cheng [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

    2017-05-21

    Particle accelerators are machines to accelerate and store charged particles, such as electrons or protons, to the energy levels for various scientific applications. A collection of charged particles usually forms a particle beam. There are three basic types of particle accelerators: linear accelerators (linac), storage-ring (or circular) accelerators, and recirculating accelerators. In a linac, particles are accelerated and pass through once along a linear or straight beamline. Storage-ring accelerators propel particles around a circular track and repetitively append the energy to the stored beam. The third type, also the most recent one in chronology, the recirculating accelerator, is designed to accelerate the particle beam in a short section of linac, circulate the beam, and then either continue to accelerate for energy boost or decelerate it for energy recovery. The beam properties of a linac machine are set at best by the initial particle sources. For storage rings, the beam equilibria are instead determined by the overall machine design. The modern recirculating machines share with linacs the advantages to both accelerate and preserve the beam with high beam quality, as well as efficiently reuse the accelerating components. The beamline design in such a machine configuration can however be much more complicated than that of linacs. As modern accelerators push toward the high-brightness or high-intensity frontier by demanding particles in a highly charged bunch (about nano-Coulomb per bunch) to concentrate in an ever-decreasing beam phase space (transverse normalized emittance about 1 μm and relative energy spread of the order of 10^-5 in GeV beam energy), the interaction amongst particles via their self-generated electromagnetic fields can potentially lead to coherent instabilities of the beam and thus pose significant challenges to the machine design and operation. In the past decade and a half, microbunching instability (MBI) has been one of the most

  4. STUDY ON FIBROUS COMPOSITES BEHAVIOUR IN HYDRODYNAMIC PROCESS OF WINE FILTRATION

    Directory of Open Access Journals (Sweden)

    Petronela Nechita

    2009-11-01

    Full Text Available This study concerns the implementation and performance evaluation of fibrous composites in sterile filtration of wine. Conditions of preparation were established having in view that the separation of particulate contaminants from liquids by depth filtration is occurring by mechanical entrapment into structural pores and by electrokinetic adsorption, and both retention mechanisms are influenced by various factors. Functional characteristics and behaviour of the filtering composite in industrial filtration of wine were evaluated. It was found that the effectiveness with which micro-organisms were retained was substantially improved by a porous structure characterized by small pores, and respectively by high resistance to air filtration, as well as by a higher content of cationic charges in the system.

  5. Nitrogen oxides emissions from the MILD combustion with the conditions of recirculation gas.

    Science.gov (United States)

    Park, Min; Shim, Sung Hoon; Jeong, Sang Hyun; Oh, Kwang-Joong; Lee, Sang-Sup

    2017-04-01

    The nitrogen oxides (NOx) reduction technology by combustion modification which has economic benefits as a method of controlling NOx emitted in the combustion process, has recently been receiving a lot of attention. Especially, the moderate or intense low oxygen dilution (MILD) combustion which applied high temperature flue gas recirculation has been confirmed for its effectiveness with regard to solid fuel as well. MILD combustion is affected by the flue gas recirculation ratio and the composition of recirculation gas, so its NOx reduction efficiency is determined by them. In order to investigate the influence of factors which determine the reduction efficiency of NOx in MILD coal combustion, this study changed the flow rate and concentration of nitrogen (N2), carbon dioxide (CO2) and steam (H2O) which simulate the recirculation gas during the MILD coal combustion using our lab-scale drop tube furnace and performed the combustion experiment. As a result, its influence by the composition of recirculation gas was insignificant and it was shown that flue gas recirculation ratio influences the change of NOx concentration greatly. We investigated the influence of factors determining the nitrogen oxides (NOx) reduction efficiency in MILD coal combustion, which applied high-temperature flue gas recirculation. Using a lab-scale drop tube furnace and simulated recirculation gas, we conducted combustion testing changing the recirculation gas conditions. We found that the flue gas recirculation ratio influences the reduction of NOx emissions the most.

  6. Evaluation of an improved air distribution system for aircraft cabin

    DEFF Research Database (Denmark)

    Pang, Liping; Xu, Jie; Fang, Lei

    2013-01-01

    An improved air distribution system for aircraft cabin was proposed in this paper. Personalized outlets were introduced and placed at the bottom of the baggage hold. Its ratio of fresh air to recirculation air and the conditioned temperature of different types of inlets were also designed carefully...

  7. Heating, Ventilation and Air-Conditioning Systems, Part of Indoor Air Quality Design Tools for Schools

    Science.gov (United States)

    The main purposes of a Heating, Ventilation, and Air-Conditioning system are to help maintain good indoor air quality through adequate ventilation with filtration and provide thermal comfort. HVAC systems are among the largest energy consumers in schools.

  8. 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.

  9. Are vacuum-filtrated reduced graphene oxide membranes symmetric?

    KAUST Repository

    Tang, Bo

    2015-12-02

    Graphene or reduced graphene oxide (rGO) membrane-based materials are promising for many advanced applications due to their exceptional properties. One of the most widely used synthesis methods for rGO membranes is vacuum filtration of graphene oxide (GO) on a filter membrane, followed by reduction, which shows great advantages such as operational convenience and good controllability. Despite vacuum-filtrated rGO membranes being widely used in many applications, a fundamental question is overlooked: are the top and bottom surfaces of the membranes formed at the interfaces with air and with the filter membrane respectively symmetric or asymmetric? This work, for the first time, reports the asymmetry of the vacuum-filtrated rGO membranes and discloses the filter membranes’ physical imprint on the bottom surface of the rGO membrane, which takes place when the filter membrane surface pores have similar dimension to GO sheets. This result points out that the asymmetric surface properties should be cautiously taken into consideration while designing the surface-related applications for GO and rGO membranes.

  10. Evaluation of a rainbow trout (Oncorhynchus mikyss) culture water recirculating system

    OpenAIRE

    Iván Sánchez O; Wilmer Sanguino O.; Ariel Gómez C.; Roberto García C

    2014-01-01

    ABSTRACTObjective. To evaluate a water recirculation system for rainbow trout fish cultures at the recirculating laboratory of the Aquaculture Engineering Production Program of University of Nariño. Materials and Methods. 324 rainbow trout (Oncorhynchus mikyss) fries were cultured in 12 plastic tanks with a capacity of 250 L in an aquaculture recirculating system the treatment system of which was made up by a conventional sedimentation tank, a fixed stand upflow biofilter with recycled PVC tu...

  11. Particle clogging in porous media. Filtration of a smectite solution

    Energy Technology Data Exchange (ETDEWEB)

    Richards, Tobias (Chalmers University of Technology, Goeteborg (Sweden))

    2010-01-15

    The goal of this project is to find out if it is possible for bentonite clay to self heal during leaching with deionized water. The investigation has focused on the formation of a filter cake made of accessory material from MX 80 and the separation of solid material when a smectite solution (1%) is pushed through the cake using a pressure difference of 5 bar. It was also in the scope of this project to design and build the necessary equipment for these experiments. In the literature review it was not found any example that the phenomenon of clogging has been used as a self-healing method previously. It was rather separated also between the clogging of a filter cake (deep bed filtration or cake filtration) and the filtration of colloidal particles. Probably because the latter are in such low concentrations in natural systems and the focus have mainly been in the transport properties of colloids within a filter cake or deep bed filter. An experimental equipment was designed and built. It consists of seven filtration cells that could operate in parallel. All of them are connected to the same source of pressure to ensure equal conditions. A system was also prepared to prevent air from dissolving in the solution because it could create an unwanted expansion in the filter cake due to lower solubility at lower pressure. The experiment showed good separation of smectite particles from the solution when it passed through the filter cake. In all tested cases, the separation was almost complete after long enough time, indicating that the cake has small enough pores to act as a geometrical hinder for the small particles. Comparison between the materials prepared at Chalmers University of Technology and at Clay Technology showed a very good agreement indicating similar properties of the produced smectite

  12. Filtrating forms of soil bacteria

    Science.gov (United States)

    Van'kova, A. A.; Ivanov, P. I.; Emtsev, V. T.

    2013-03-01

    Filtrating (ultramicroscopic) forms (FF) of bacteria were studied in a soddy-podzolic soil and the root zone of alfalfa plants as part of populations of the most widespread physiological groups of soil bacteria. FF were obtained by filtering soil solutions through membrane filters with a pore diameter of 0.22 μm. It was established that the greater part of the bacteria in the soil and in the root zone of the plants has an ultramicroscopic size: the average diameter of the cells is 0.3 μm, and their length is 0.6 μm, which is significantly less than the cell size of banal bacteria. The number of FF varies within a wide range depending on the physicochemical conditions of the habitat. The FF number's dynamics in the soil is of a seasonal nature; i.e., the number of bacteria found increases in the summer and fall and decreases in the winter-spring period. In the rhizosphere of the alfalfa, over the vegetation period, the number of FF and their fraction in the total mass of the bacteria increase. A reverse tendency is observed in the rhizoplane. The morphological particularities (identified by an electron microscopy) and the nature of the FF indicate their physiological activity.

  13. PDF-based heterogeneous multiscale filtration model.

    Science.gov (United States)

    Gong, Jian; Rutland, Christopher J

    2015-04-21

    Motivated by modeling of gasoline particulate filters (GPFs), a probability density function (PDF) based heterogeneous multiscale filtration (HMF) model is developed to calculate filtration efficiency of clean particulate filters. A new methodology based on statistical theory and classic filtration theory is developed in the HMF model. Based on the analysis of experimental porosimetry data, a pore size probability density function is introduced to represent heterogeneity and multiscale characteristics of the porous wall. The filtration efficiency of a filter can be calculated as the sum of the contributions of individual collectors. The resulting HMF model overcomes the limitations of classic mean filtration models which rely on tuning of the mean collector size. Sensitivity analysis shows that the HMF model recovers the classical mean model when the pore size variance is very small. The HMF model is validated by fundamental filtration experimental data from different scales of filter samples. The model shows a good agreement with experimental data at various operating conditions. The effects of the microstructure of filters on filtration efficiency as well as the most penetrating particle size are correctly predicted by the model.

  14. Exhaust Gas Recirculation in Gas Turbines for Reduction of CO2 Emissions; Combustion Testing with Focus on Stability and Emissions

    Directory of Open Access Journals (Sweden)

    Johan E. Hustad

    2005-12-01

    Full Text Available Exhaust gas recirculation can be applied with the intention of reducing CO2 emissions. When a fraction of the exhaust gas is injected in the entry of a gas turbine, the amount of CO2 in the exhaust gas not being recirculated will be higher and less complicated to capture. However, with this change in combustion air composition, especially the reduced concentration of oxygen, the combustion process will be affected. The lower oxygen concentration decreases the stability and the increased amount of CO2, H2O and N2 will decrease the combustion temperature and thus, the NOx emissions. Testing has been performed on a 65 kW gas turbine combustor, to investigate the effect of adding N2, CO2 and O2 in the combustion process, with focus on stability and emissions of NOx. Results show that adding N2 and CO2 decreases the NOx emissions, whereas O2 addition increases the NOx emissions. The tests have been performed both in a diffusion flame (pilot burner and a premixed flame (main burner, and for additives being injected with the fuel or with the air stream. Addition into the fuel stream is proven to affect the NOx emissions the most. The stability limits of the flames are indicated with respect to mass-based additive-to-fuel ratios.

  15. Applying rotary jet heads for mixing and mass transfer in a forced recirculation tank reactor system

    DEFF Research Database (Denmark)

    Nordkvist, Mikkel; Grotkjær, Thomas; Hummer, J.S.

    2003-01-01

    An approximation to an ideally mixed tank reactor can be obtained by vigorous stirring with mechanical mixers. For an aerated reactor the gas dispersion contributes to the mixing process. Mixing can also be achieved by recirculation of a portion of the liquid through either an internal...... at 1-9 bar gauge pressure into the bulk liquid. Liquid feed can be added to the bulk volume or it may be injected into the pressurized recirculation loop. Gas is always fed to the recirculation loop, and the heat of reaction is removed in a plate-type heat exchanger inserted in the recirculation loop...

  16. A power recirculating test rig for ball screw endurance tests

    Directory of Open Access Journals (Sweden)

    Giberti Hermes

    2016-01-01

    Full Text Available A conceptual design of an innovative test rig for endurance tests of ball screws is presented in this paper. The test rig layout is based on the power recirculating principle and it also allows to overtake the main critical issues of the ball screw endurance tests. Among these there are the high power required to make the test, the lengthy duration of the same and the high loads between the screw and the frame that holds it. The article describes the test rig designed scheme, the kinematic expedients to be adopted in order to obtain the required performance and functionality and the sizing procedure to choose the actuation system.

  17. A recirculating hydroponic system for studying peanut (Arachis hypogaea L.)

    Science.gov (United States)

    Mackowiak, C. L.; Wheeler, R. M.; Stutte, G. W.; Yorio, N. C.; Ruffe, L. M.; Sager, J. C. (Principal Investigator)

    1998-01-01

    Peanut (Arachis hypogaea L.) plants were grown hydroponically, using continuously recirculating nutrient solution. Two culture tray designs were tested; one tray design used only nutrient solution, while the other used a sphagnum-filled pod development compartment just beneath the cover and above the nutrient solution. Both trays were fitted with slotted covers to allow developing gynophores to reach the root zone. Peanut seed yields averaged 350 gm-2 dry mass, regardless of tray design, suggesting that substrate is not required for hydroponic peanut production.

  18. Tools to Predict Beam Breakup in Recirculating Linacs

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Beard; Nikolitsa Merminga; Byung Yunn

    2003-05-01

    An important limitation on the maximum beam current in a recirculating linac is due to beam breakup caused by higher order modes (HOM) excited in the RF cavities. A HOM delivers a transverse kick to a beam bunch, the bunch on the next pass can then drive the HOM and cause it to grow until the beam is lost. Two codes, MATBBU1 and TDBBU2, have been written to estimate the threshold current for a set of HOMs and accelerator optics. The relative merits and limitations of each is discussed in detail.

  19. Laser scanning of a recirculation zone on the Bolund escarpment

    DEFF Research Database (Denmark)

    Mann, Jakob; Angelou, Nikolas; Sjöholm, Mikael;

    2012-01-01

    Rapid variations in the height of the recirculation zone are measured with a scanning wind lidar over a small escarpment on the Bolund Peninsula. The lidar is essentially a continuous-wave laser Doppler anemometer with the capability of rapidly changing the focus distance and the beam direction....... The instrument measures the line-ofsight velocity 390 times per second and scans ten wind profiles from the ground up to seven meters per second. The results will be used to test computational fluid dynamics models for flow over terrain, and has relevance for wind energy. The development of multiple lidar...

  20. ENVIRONMENTAL TECHNOLOGY VERIFICATION, TEST REPORT OF CONTROL OF BIOAEROSOLS IN HVAC SYSTEMS, FILTRATION GROUP, AEROSTAR FP-98 MINIPLEAT V-BLANK FILTER

    Science.gov (United States)

    The Environmental Technology Verification report discusses the technology and performance of the AeroStar FP-98 Minipleat V-Bank Filter air filter for dust and bioaerosol filtration manufactured by Filtration Group. The pressure drop across the filter was 137 Pa clean and 348 Pa ...

  1. ENVIRONMENTAL TECHNOLOGY VERIFICATION, TEST REPORT OF CONTROL OF BIOAEROSOLS IN HVAC SYSTEMS, FILTRATION GROUP, AEROSTAR "C-SERIES" POLYESTER PANEL FILTER

    Science.gov (United States)

    The Environmental Technology Verification report discusses the technology and performance of the AeroStar "C-Series" Polyester Panel Filter air filter for dust and bioaerosol filtration manufactured by Filtration Group. The pressure drop across the filter was 126 Pa clean and 267...

  2. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT--BAGHOUSE FILTRATION PRODUCTS, W.L. GORE ASSOC., INC.

    Science.gov (United States)

    The U.S. Environmental Protection Agency Air Pollution Control Technology (APCT) Verification Center evaluates the performance of baghouse filtration products used primarily to control PM2.5 emissions. This verification statement summarizes the test results for W.L. Gore & Assoc....

  3. A bubble- and clogging-free microfluidic particle separation platform with multi-filtration.

    Science.gov (United States)

    Cheng, Yinuo; Wang, Yue; Ma, Zengshuai; Wang, Wenhui; Ye, Xiongying

    2016-11-15

    Microfiltration is a compelling method to separate particles based on their distinct size and deformability. However, this approach is prone to clogging after processing a certain number of particles and forming bubbles in the separation procedure, which often leads to malfunctioning of devices. In this work, we report a bubble-free and clogging-free microfluidic particle separation platform with high throughput. The platform features an integrated bidirectional micropump, a hydrophilic microporous filtration membrane and a hydrophobic porous degassing membrane. The bidirectional micropump enables the fluid to flow back and forth repeatedly, which flushes the filtration membrane and clears the filtration micropores for further filtration, and to flow forward to implement multi-filtration. The hydrophobic porous membrane on top of the separation channel removes air bubbles forming in the separation channel, improving the separation efficiency and operational reliability. The microbead mixture and undiluted whole blood were separated using the microfluidic chip. After 5 cycles of reverse flushing and forward re-filtration, a 2857-fold enrichment ratio and an 89.8% recovery rate of 10 μm microbeads were achieved for microbead separation with 99.9% removal efficiency of 2 μm microbeads. After 8 cycles, white blood cells were effectively separated from whole blood with a 396-fold enrichment ratio and a 70.6% recovery rate at a throughput of 39.1 μl min(-1), demonstrating that the platform can potentially be used in biomedical applications.

  4. Metal reduction at bulk chemical filtration

    Science.gov (United States)

    Umeda, Toru; Daikoku, Shusaku; Tsuzuki, Shuichi; Murakami, Tetsuya

    2017-03-01

    OK73 thinner and cyclohexanone, both of which were spiked with metals were passed through Nylon 6,6 filter, varying flow rate, which include the conditions of both point-of-use and bulk filtrations. The influent and effluent metal concentrations were measured using ICP-MS for metal removal efficiency of the filtration. As a result, removal efficiency for some metals descended depending on the flow rate, while others maintained. Slower flow rate is recommended to maintain low metal concentration in bulk filtration based on the result. Metals in cyclohexanone were reduced at higher efficiency than in OK73 thinner, agrees with a metal removal model of hydrophilic adsorbent in organic solvent, evidenced in our previous paper. Further, metal reduction on 300 mm φ Si wafer after coating organic solvents with Nylon 6,6 filtration was evidenced with TREX analysis.

  5. Filtration in coal liquefaction - Influence of filtration conditions in non-hydrogenated systems

    Science.gov (United States)

    Clarke, J. W.; Rantell, T. D.

    1980-01-01

    A series of experiments has been carried out to study the effects of filtration conditions upon the rate of filtration of non-hydrogenated coal digests. The results show the dependence of cake resistivity on both the filtration temperature and pressure. Filter cakes were found to be compressible, resulting in smaller increases in rate with increasing pressure than with incompressible cakes. The filtration temperature determines the packing of residual solids in the cake which in turn affects the cake resistivity. An empirical relation has been derived between filtration temperature and resistivity. With increasing temperature there is an increase in filtration rate due to the reduced viscosity, but a reduction owing to a higher packing density of solids in the filter cake.

  6. Complications and Management of the Filtration Bleb

    Institute of Scientific and Technical Information of China (English)

    Clement; W; N; Chan

    1992-01-01

    Filtration surgery is the commonest operation performed for closed angle or open angle glaucoma when medical treatment or laser trabeculoplasty has failed to control the intraocular pressure. It is characterized by the formation of an artificial drainage fistula between the anterior chamber and subconjunctival space. The successful operation is evidenced by the appearance of a subconjunctival filtration bleb which in turn depends on the patency of this pathway. Despite numerous modification, the procedu...

  7. The Glomerular Filtration Barrier: Components and Crosstalk

    OpenAIRE

    Madhav C. Menon; Chuang, Peter Y.; Cijiang John He

    2012-01-01

    The glomerular filtration barrier is a highly specialized blood filtration interface that displays a high conductance to small and midsized solutes in plasma but retains relative impermeability to macromolecules. Its integrity is maintained by physicochemical and signalling interplay among its three core constituents—the glomerular endothelial cell, the basement membrane and visceral epithelial cell (podocyte). Understanding the pathomechanisms of inherited and acquired human diseases as well...

  8. Design validation and performance of closed loop gas recirculation system

    Science.gov (United States)

    Kalmani, S. D.; Joshi, A. V.; Majumder, G.; Mondal, N. K.; Shinde, R. R.

    2016-11-01

    A pilot experimental set up of the India Based Neutrino Observatory's ICAL detector has been operational for the last 4 years at TIFR, Mumbai. Twelve glass RPC detectors of size 2 × 2 m2, with a gas gap of 2 mm are under test in a closed loop gas recirculation system. These RPCs are continuously purged individually, with a gas mixture of R134a (C2H2F4), isobutane (iC4H10) and sulphur hexafluoride (SF6) at a steady rate of 360 ml/h to maintain about one volume change a day. To economize gas mixture consumption and to reduce the effluents from being released into the atmosphere, a closed loop system has been designed, fabricated and installed at TIFR. The pressure and flow rate in the loop is controlled by mass flow controllers and pressure transmitters. The performance and integrity of RPCs in the pilot experimental set up is being monitored to assess the effect of periodic fluctuation and transients in atmospheric pressure and temperature, room pressure variation, flow pulsations, uniformity of gas distribution and power failures. The capability of closed loop gas recirculation system to respond to these changes is also studied. The conclusions from the above experiment are presented. The validations of the first design considerations and subsequent modifications have provided improved guidelines for the future design of the engineering module gas system.

  9. Designing and Testing of Self-Cleaning Recirculating Zebrafish Tanks.

    Science.gov (United States)

    Nema, Shubham; Bhargava, Yogesh

    2016-08-01

    Maintenance of large number of zebrafish in captive conditions is a daunting task. This can be eased by the use of recirculating racks with self-cleaning zebrafish tanks. Commercially available systems are costly, and compatibility of intercompany products has never been investigated. Although various cost-effective designs and methods of construction of custom-made recirculating zebrafish racks are available in literature, the design of self-cleaning zebrafish tanks is still not available. In this study, we report the design and method of construction of the self-cleaning unit, which can be fitted in any zebrafish tank. We validated the design by investigating sediment cleaning process in rectangular and cylindrical tank geometries using time lapse imaging. Our results suggest that for both tank geometries, the tanks fitted with self-cleaning unit provided superior sediment cleaning than the tanks fitted with overflow-drain unit. Although the self-cleaning unit could clean the sediment completely from both geometries over prolonged period, the cleaning of sediments was faster in the cylindrical tank than the rectangular tank. In conclusion, cost and efforts of zebrafish maintenance could be significantly reduced through the installation of our self-cleaning unit in any custom-made zebrafish tank.

  10. CONVECTIVE HEAT TRANSFER IN CYCLONE DEVICE WITH EXTERNAL GAS RECIRCULATION

    Directory of Open Access Journals (Sweden)

    S. V. Karpov

    2016-01-01

    Full Text Available The article considers the convective heat transfer on the surface of a hollow cylinder or several billets in a cyclone device with the new principle of external gas recirculation. According to this principle, transport of coolant from the lateral surface of the chamber, where the temperature is the highest, in the axial region is being fulfilled due to the pressure drop between the wall and axial areas of cyclonic flow. Dependency analysis of average and local heat transfer coefficients from operational and geometrical parameters has been performed; the generalized similarity equations for the calculation of the latter have been suggested. It is demonstrated that in case of download of a cyclone chamber with several billets, the use of the considered scheme of the external recirculation due to the specific characteristics of aerodynamics practically does not lead to noticeable changes in the intensity of convective heat transfer. Both experimental data and the numerical simulation results obtained with the use of OpenFOAM platform were used in the work. The investigations fulfilled will expand the area of the use of cyclone heating devices.

  11. Continuous hydroponic wheat production using a recirculating system

    Science.gov (United States)

    Mackowiak, C. L.; Owens, L. P.; Hinkle, C. R.; Prince, R. P.

    1989-01-01

    Continuous crop production, where plants of various ages are growing simultaneously in a single recirculating nutrient solution, is a possible alternative to batch production in a Controlled Ecological Life Support System. A study was conducted at John F. Kennedy Space Center where 8 trays (0.24 sq m per tray) of Triticum aestivum L. Yecora Rojo were grown simultaneously in a growth chamber at 23 C, 65 percent relative humidity, 1000 ppm CO2, continuous light, with a continuous flow, thin film nutrient delivery system. The same modified Hoagland nutrient solution was recirculated through the plant trays from an 80 L reservoir throughout the study. It was maintained by periodic addition of water and nutrients based on chemical analyses of the solution. The study was conducted for 216 days, during which 24 trays of wheat were consecutively planted (one every 9 days), 16 of which were grown to maturity and harvested. The remaining 8 trays were harvested on day 216. Grain yields averaged 520 g m(exp -2), and had an average edible biomass of 32 percent. Consecutive yields were unaffected by nutrient solution age. It was concluded that continual wheat production will work in this system over an extended period of time. Certain micronutrient deficiencies and toxicities posed problems and must be addressed in future continuous production systems.

  12. Economic evaluation of recirculation as a method of pile cooling

    Energy Technology Data Exchange (ETDEWEB)

    Carson, A.B.; Purcell, R.H.; McEwen, L.H.

    1954-04-07

    Reductions in irradiation costs and increases in production rate have provided a continuing incentive for more efficient operation of the Hanford Piles. These improvements have been obtained by means of higher specific powers, greater water flow rates, and better water utilization. However, the extent of the improvements which can be made in this manner may be limited by such factors as tube and slug corrosion, slug stability, and graphite damage rates at higher operating temperatures. Water purification and pumping costs are also factors to be considered. New slug designs are being developed which may be capable of much higher specific power operation. Higher graphite temperatures may also prove feasible, but the water plant performance limitations for the present single pass cooling systems may prove much more expensive to relieve. The use of recirculating cooling water as a means of attaining higher temperature, higher power operation has received preliminary study. A preliminary economic evaluation of an operating area equipped for recirculation versus single pass cooling is needed to better determine the relative merits of the two cooling methods. This report presents the results of such an evaluation and discusses the direction of future development work in the field of pile cooling.

  13. A high temperature granulation process for ecological ash recirculation

    Energy Technology Data Exchange (ETDEWEB)

    Sundqvist, Thomas

    1999-07-01

    This thesis is a summary of three papers dealing with new technologies for facilitating ecological biomass ash recirculation back to forest and farm lands. The present outtake of biomass for paper and energy production may be incompatible with a sustainable forestry. The cycle of nutrients contained in the biomass extracted must be closed by ash recirculation in an environmental compatible way. This implies stabilization of the loose ashes/rest-products to a product with low heavy metal contents, controlled leaching properties and a high spreadability. In the present work, two different techniques were evaluated for the possibilities to separate heavy metals from the nutrient elements by utilizing high process temperatures to vaporize the unwanted metals from the condensed bulk materials. The results indicated that direct in-situ separation in fluidized bed combustion systems is possible, but requires too high process temperatures to be practically attractive. On the other hand, the new proposed high temperature treatment method for granulated raw materials was found to significantly separate As, Cd and Pb, with separation efficiencies exceeding 90 % at optimal operating conditions. In addition, the results indicated that the treatment method could be used to significantly delay and control the leaching characteristics, as well as the content of products of incomplete combustion of the produced granules.

  14. Turbulent characteristics of shear-thinning fluids in recirculating flows

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, A.S. [Inst. Superior de Engenharia do Porto (Portugal). Dept. de Engenharia Quimica; Pinho, F.T. [Centro de Estudos de Fenomenos de Transporte, Departamento de Engenharia Mecanica e Gestao Industrial, Faculdade de Engenharia da Universidade do Porto, Rua dos Bragas, 4050-123 Porto (Portugal)

    2000-03-01

    A miniaturised fibre optic laser-Doppler anemometer was used to carry out a detailed hydrodynamic investigation of the flow downstream of a sudden expansion with 0.1-0.2% by weight shear-thinning aqueous solutions of xanthan gum. Upstream of the sudden expansion the pipe flow was fully-developed and the xanthan gum solutions exhibited drag reduction with corresponding lower radial and tangential normal Reynolds stresses, but higher axial Reynolds stress near the wall and a flatter axial mean velocity profile in comparison with Newtonian flow. The recirculation bubble length was reduced by more than 20% relative to the high Reynolds number Newtonian flow, and this was attributed to the occurrence further upstream of high turbulence for the non-Newtonian solutions, because of advection of turbulence and earlier high turbulence production in the shear layer. Comparisons with the measurements of Escudier and Smith (1999) with similar fluids emphasized the dominating role of inlet turbulence. The present was less anisotropic, and had lower maximum axial Reynolds stresses (by 16%) but higher radial turbulence (20%) than theirs. They reported considerably longer recirculating bubble lengths than we do for similar non-Newtonian fluids and Reynolds numbers. (orig.)

  15. Simultaneous temperature and exhaust-gas recirculation-measurements in a homogeneous charge-compression ignition engine by use of pure rotational coherent anti-Stokes Raman spectroscopy

    Science.gov (United States)

    Weikl, Markus C.; Beyrau, Frank; Leipertz, Alfred

    2006-05-01

    Pure rotational coherent anti-Stokes Raman spectroscopy was used for the simultaneous determination of temperature and exhaust-gas recirculation in a homogeneous charge-compression ignition engine. Measurements were performed in a production-line four-cylinder gasoline engine operated with standard gasoline fuel through small optical line-of-sight accesses. The homogenization process of fresh intake air with recirculated exhaust gas was observed during the compression stroke, and the effect of charge temperature on combustion timing is shown. Single-pulse coherent anti-Stokes Raman spectroscopy spectra could not only be taken in the compression stroke but also during the gas-exchange cycle and after combustion. Consequently, the used method has been shown to be suitable for the investigation of two of the key parameters for self-ignition, namely temperature and charge composition.

  16. Properties of the filtrate from treatment of pig manure by filtration method

    Directory of Open Access Journals (Sweden)

    Makara Agnieszka

    2017-02-01

    Full Text Available This paper presents properties of filtrate obtained from pig manure using the AMAK treatment process, which includes the mineralization of macro- and microfertilizer components by the hydrolyzing of organic matter into forms that are bioavailable to plants. Filtration produced two products, sediment and filtrate. The quality of the filtrate allowed for its use as a substitute of water to irrigate crops. Concentrations of heavy metals are very low and therefore the quality of the filtrate fully complies with European standard concerning fertilizers. The used mineralization process practically eliminated odors from the filtrate. The reduction of specific odor emission by 99.1-99.5% in samples taken from above the filtrate, respectively compared to the odor concentration found in samples taken from above raw pig manure. Sediment could be used as raw material for production of mineral-organic fertilizer. Filtrate and filtration sediments analyses show that the majority of nitrogen and other fertilizing compounds included in raw pig manure remains in sediment.

  17. Unit process engineering for water quality control and biosecurity in marine water recirculating systems

    Science.gov (United States)

    High-intensity systems that treat and recirculate water must maintain a culture environment that can sustain near optimum fish health and growth at the design carrying capacity. Water recirculating systems that use centralized treatment systems can benefit from the economies of scale to decrease th...

  18. Low Load Model of a Once-through Boiler with Recirculation

    DEFF Research Database (Denmark)

    Trangbæk, Klaus

    2006-01-01

    A dynamic simulation model of a once-through boiler in low to medium load is developed. When the system is in low load, water from the evaporator is recirculated through a bottle. This recirculation system is included in the model, which is then shown to fit closed-loop data from a real plant...

  19. 21 CFR 177.2910 - Ultra-filtration membranes.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ultra-filtration membranes. 177.2910 Section 177... Components of Articles Intended for Repeated Use § 177.2910 Ultra-filtration membranes. Ultra-filtration... the processing of food, under the following prescribed conditions; (a)(1) Ultra-filtration...

  20. Removal of polycyclic aromatic hydrocarbons (PAH) during anaerobic digestion with recirculation of ozonated digested sludge

    Energy Technology Data Exchange (ETDEWEB)

    Bernal-Martinez, Arodi; Patureau, Dominique; Delgenes, Jean-Philippe [INRA, UR 050, Laboratoire de Biotechnologie de l' Environnement, Avenue des Etangs, Narbonne F11100 (France); Carrere, Helene [INRA, UR 050, Laboratoire de Biotechnologie de l' Environnement, Avenue des Etangs, Narbonne F11100 (France)], E-mail: carrere@supagro.inra.fr

    2009-03-15

    PAH are particularly monitored because of their carcinogenic properties and their ubiquity in the environment. Their presence in municipal sewage sludge is a major problem due to the environmental risks associated with the sludge spreading on agricultural soils. The objective of this work was to asses the removal of PAH naturally present in sludge by continuous anaerobic digestion with recirculation of ozonated sludge. Recirculation of ozonated digested sludge allowed to enhance PAH removals, the highest efficiency was obtained with the highest ozone dose (0.11 g O{sub 3}/g{sub TS}). In order to study the effect of recirculation, a reactor was operated without recirculation but was fed with a mixture of raw and ozonated digested sludge. This process led to the best performances in terms of PAH and solid removals. This pointed out some accumulation of nonbiodegradable or recalcitrant compounds during recirculation assay. Smallest and most soluble compounds presented the highest biodegradation efficiencies.

  1. Pulsed-focusing recirculating linacs for muon acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Rolland [Muons, Inc., Batavia, IL (United States)

    2014-12-31

    Since the muon has a short lifetime, fast acceleration is essential for high-energy applications such as muon colliders, Higgs factories, or neutrino factories. The best one can do is to make a linear accelerator with the highest possible accelerating gradient to make the accelerating time as short as possible. However, the cost of such a single linear accelerator is prohibitively large due to expensive power sources, cavities, tunnels, and related infrastructure. As was demonstrated in the Thomas Jefferson Accelerator Facility (Jefferson Lab) Continuous Electron Beam Accelerator Facility (CEBAF), an elegant solution to reduce cost is to use magnetic return arcs to recirculate the beam through the accelerating RF cavities many times, where they gain energy on each pass. In such a Recirculating Linear Accelerator (RLA), the magnetic focusing strength diminishes as the beam energy increases in a conventional linac that has constant strength quadrupoles. After some number of passes the focusing strength is insufficient to keep the beam from going unstable and being lost. In this project, the use of fast pulsed quadrupoles in the linac sections was considered for stronger focusing as a function of time to allow more successive passes of a muon beam in a recirculating linear accelerator. In one simulation, it was shown that the number of passes could be increased from 8 to 12 using pulsed magnet designs that have been developed and tested. This could reduce the cost of linac sections of a muon RLA by 8/12, where more improvement is still possible. The expense of a greater number of passes and corresponding number of return arcs was also addressed in this project by exploring the use of ramped or FFAG-style magnets in the return arcs. A better solution, invented in this project, is to use combined-function dipole-quadrupole magnets to simultaneously transport two beams of different energies through one magnet string to reduce costs of return arcs by almost a factor of

  2. Performance model of a recirculating stack nickel hydrogen cell

    Science.gov (United States)

    Zimmerman, Albert H.

    1994-01-01

    A theoretical model of the nickel hydrogen battery cell has been utilized to describe the chemical and physical changes during charge and overcharge in a recirculating stack nickel hydrogen cell. In particular, the movement of gas and electrolyte have been examined as a function of the amount of electrolyte put into the cell stack during cell activation, and as a function of flooding in regions of the gas screen in this cell design. Additionally, a two-dimensional variation on this model has been utilized to describe the effects of non-uniform loading in the nickel-electrode on the movement of gas and electrolyte within the recirculating stack nickel hydrogen cell. The type of nonuniform loading that has been examined here is that associated with higher than average loading near the surface of the sintered nickel electrode, a condition present to some degree in many nickel electrodes made by electrochemical impregnation methods. The effects of high surface loading were examined primarily under conditions of overcharge, since the movement of gas and electrolyte in the overcharging condition was typically where the greatest effects of non-uniform loading were found. The results indicate that significant changes in the capillary forces between cell components occur as the percentage of free volume in the stack filled by electrolyte becomes very high. These changes create large gradients in gas-filled space and oxygen concentrations near the boundary between the separator and the hydrogen electrode when the electrolyte fill is much greater than about 95 percent of the stack free volume. At lower electrolyte fill levels, these gaseous and electrolyte gradients become less extreme, and shift through the separator towards the nickel electrode. Similarly, flooding of areas in the gas screen cause higher concentrations of oxygen gas to approach the platinum/hydrogen electrode that is opposite the back side of the nickel electrode. These results illustrate the need for

  3. PULSED-FOCUSING RECIRCULATING LINACS FOR MUON ACCELERATION

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Rolland PAUL

    2014-12-31

    Since the muon has a short lifetime, fast acceleration is essential for high-energy applications such as muon colliders, Higgs factories, or neutrino factories. The best one can do is to make a linear accelerator with the highest possible accelerating gradient to make the accelerating time as short as possible. However, the cost of such a single linear accelerator is prohibitively large due to expensive power sources, cavities, tunnels, and related infrastructure. As was demonstrated in the Thomas Jefferson Accelerator Facility (Jefferson Lab) Continuous Electron Beam Accelerator Facility (CEBAF), an elegant solution to reduce cost is to use magnetic return arcs to recirculate the beam through the accelerating RF cavities many times, where they gain energy on each pass. In such a Recirculating Linear Accelerator (RLA), the magnetic focusing strength diminishes as the beam energy increases in a conventional linac that has constant strength quadrupoles. After some number of passes the focusing strength is insufficient to keep the beam from going unstable and being lost. In this project, the use of fast pulsed quadrupoles in the linac sections was considered for stronger focusing as a function of time to allow more successive passes of a muon beam in a recirculating linear accelerator. In one simulation, it was shown that the number of passes could be increased from 8 to 12 using pulsed magnet designs that have been developed and tested. This could reduce the cost of linac sections of a muon RLA by 8/12, where more improvement is still possible. The expense of a greater number of passes and corresponding number of return arcs was also addressed in this project by exploring the use of ramped or FFAG-style magnets in the return arcs. A better solution, invented in this project, is to use combined-function dipole-quadrupole magnets to simultaneously transport two beams of different energies through one magnet string to reduce costs of return arcs by almost a factor of

  4. Sanguinarine non- versus re-circulation during isolated heart perfusion--a Jekyll and Hyde effect?

    Science.gov (United States)

    Webster, I; Smith, A; Lochner, A; Huisamen, B

    2014-10-01

    In isolated rat heart perfusion experiments, drug administration occurs via retrograde perfusion. This can be done in the non-recirculating mode (coronary effluent is discarded), or recirculating mode (coronary effluent is collected and reused). It was recently observed in our lab while using sanguinarine, an MKP-1 inhibitor, that there were differences in outcomes depending on the mode of recirculation used. Hearts from control (C); diet-induced obese (DIO) Wistar rats and their age matched controls (AMC) were perfused on the rig. Hearts received buffer (control) , insulin, sanguinarine, insulin + sanguinarine combination or methanol (vehicle) for 15 mins pre- and 10 mins post-ischemia in either a non- or re-circulating manner. Hearts were subjected to 15 mins global ischemia and 30 mins reperfusion. Mechanical function was documented pre- and post-ischemia . When not-recirculated , sanguinarine alone and in combination with insulin in C, DIO and AMC groups, caused a significant decrease in functional recovery during reperfusion. However, when the coronary effluent was recirculated, hearts perfused with sanguinarine or sanguinarine + insulin exhibited a significant recovery in function when compared with their non-recirculation counterparts (p < 0.01). No differences were seen with either control, insulin nor vehicle hearts. Sanguinarine elicited a vast improvement in perfusion outcomes when recirculated compared to non-recirculation . Since this was seen during perfusion only when sanguinarine was present, it is possible that recirculating reperfusion of the drug caused profound changes in its composition. More investigation is needed into the mechanisms involved. Thus caution should be exercised by researchers when designing a perfusion protocol for drug research.

  5. Novel Particulate Air-Filtration Media: Market Survey

    Science.gov (United States)

    2013-02-01

    12 4.30 National Nonwovens .........................................................................................12...velocity increases the collection efficiency of the filter. In the case of flat sheet electrets ( nonwoven electrostatic charged media), the thickness can...including nonwoven , woven, and electret and combinations of media. Some of the manufacturers identified themselves as specializing in biofiltration or

  6. Exhaust Gas Recirculation Technology (EGR)%废气再循环系统EGR的探讨

    Institute of Scientific and Technical Information of China (English)

    桂林; 孙亮

    2012-01-01

    With the continuous improvement of economic level and living standards, an explosion of car makes easier to people in the life, but also causes serious air pollution. Exhaust gas recirculation technology (EGR) is the more effective emission control means. By a typical structure introduction, this paper gives an indepth analysis about how exhaust gas recirculation system works and the control strategies.%随着经济水平、生活水平的不断提高,汽车保有量激增,在给人们生活带来便利的同时,也造成了十分严重的大气污染。废气再循环技术(EGR),是目前比较有效地尾气控制手段。通过典型结构的介绍,深入分析废气再循环系统的工作原理、控制策略等。

  7. Increasing EDV Range through Intelligent Cabin Air Handling Strategies: Annual Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Leighton, Daniel [National Renewable Energy Lab. (NREL), Golden, CO (United States); Rugh, John [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-08-01

    Computational fluid dynamics (CFD) simulations of a Ford Focus Electric demonstrated that a split flow heating, ventilating and air conditioning (HVAC) system with rear recirculation ducts can reduce cabin heating loads by up to 57.4% relative to full fresh air usage under some conditions (steady state, four passengers, ambient temperature of -5 deg C). Simulations also showed that implementing a continuous recirculation fraction control system into the original equipment manufacturer (OEM) HVAC system can reduce cabin heating loads by up to 50.0% relative to full fresh air usage under some conditions (steady state, four passengers, ambient temperature of -5 deg C). Identified that continuous fractional recirculation control of the OEM system can provide significant energy savings for EVs at minimal additional cost, while a split flow HVAC system with rear recirculation ducts only provides minimal additional improvement at significant additional cost.

  8. Recycling crop residues for use in recirculating hydroponic crop production

    Science.gov (United States)

    Mackowiak, C. L.; Garland, J. L.; Sager, J. C.

    1996-01-01

    As part of bioregenerative life support feasibility testing by NASA, crop residues are being used to resupply elemental nutrients to recirculating hydroponic crop production systems. Methods for recovering nutrients from crop residues have evolved from water soaking (leaching) to rapid aerobic bioreactor processing. Leaching residues recovered the majority of elements but it also recovered significant amounts of soluble organics. The high organic content of leachates was detrimental to plant growth. Aerobic bioreactor processing reduced the organic content ten-fold, which reduced or eliminated phytotoxic effects. Wheat and potato production studies were successful using effluents from reactors having with 8- to 1-day retention times. Aerobic bioreactor effluents supplied at least half of the crops elemental mass needs in these studies. Descriptions of leachate and effluent mineral content, biomass productivity, microbial activity, and nutrient budgets for potato and wheat are presented.

  9. Releasing behavior of copper in recirculated bioreactor landfill.

    Science.gov (United States)

    Long, Yu-Yang; Hu, Li-Fang; Jiang, Chen-Jing; Fang, Cheng-Ran; Wang, Feng-Ping; Shen, Dong-Sheng

    2009-04-01

    The purpose of this study was to determine the releasing behavior of copper in municipal solid waste (MSW) in landfill with respect to refuse and leachate as an inseparable system. Two simulated bioreactor landfills, one with leachate recirculation and the other without, were operated in room temperature for 320 days. Copper in refuse showed behaviors of staggered migration and retention, which corresponded with the degradation process of landfill obviously. The significant different amounts of Cu2+ leached out from refuse into leachate of two landfills were 24.74 mg and 118.53 mg after 320 days' operation, respectively. It also reflected the releasing behavior of copper in landfill refuse at different stage accordingly. The results confirmed that the refuse in landfill had high potential of secondary pollution after closure.

  10. Removal of Pollutants of Landfill Leachate by Recirculation

    Institute of Scientific and Technical Information of China (English)

    LI Ye; WANG Lina; ZHENG Shizhong

    2008-01-01

    S After leached from municipal solid waste landfill was treated by recirculation, the concentration of pollutants decreases greatly, and the moisture content of the solid waste in landfill site was increased and waste stabilization rate was accelerated. Compared with traditional treatment methods, this method offers more important practical values, including short investment, enhanced treatment efficiency and facilitated operation and management. The experimental results indicated that a 99.9% removel of ammonia nitrogen and an 80.5% removal of COD were obtained, when hydraulic power surface load is 15.92 L/m2·d, and organic surface load is 25.54 g/m2·d.

  11. Fuzzy Logic Controller based on geothermal recirculating aquaculture system

    Directory of Open Access Journals (Sweden)

    Hanaa M. Farghally

    2014-01-01

    Full Text Available One of the most common uses of geothermal heat is in recirculation aquaculture systems (RAS where the water temperature is accurately controlled for optimum growing conditions for sustainable and intensive rearing of marine and freshwater fish. This paper presents a design for RAS rearing tank and brazed heat exchanger to be used with geothermal energy as a source of heating water. The heat losses from the RAS tank are calculated using Geo Heat Center Software. Then a plate type heat exchanger is designed using the epsilon – NTU analysis method. For optimal growth and abundance of production, a Fuzzy Logic control (FLC system is applied to control the water temperature (29 °C. A FLC system has several advantages over conventional techniques; relatively simple, fast, adaptive, and its response is better and faster at all atmospheric conditions. Finally, the total system is built in MATLAB/SIMULINK to study the overall performance of control unit.

  12. Experiments With Recirculating Target for F-18 Production

    Science.gov (United States)

    Kiselev, M. Y.

    2003-08-01

    Approximately 10 ml of O-18 water was loaded in an apparatus containing a 5 ml storage vessel, pump, silver target attached to a cyclotron, filter, backpressure regulator, conductivity meter, several valves and ion exchange cartridges. The water was continuously pumped through the target during proton bombardment at a rate 5 ml/min. Continuous irradiation with beam current ranging from 10 to 50 uA was conducted while pressure, temperature and conductivity were continuously monitored. The results indicate that recirculating of the target water can increase production of F-18 in relation to consumed O-18 water material. It can also increase productivity by eliminating idle periods for re-filling the target. A backpressure regulator can precisely control target pressure. This method also allows for continuous monitoring of the target material temperature, pressure, conductivity and accumulated radioactivity. Results of these observations provide important information about target performance and physical processes taking place inside the target.

  13. Numerical investigation of recirculation in the UTSI MHD combustor

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, R.J.; Lee, J.J.; Giel, T.V. Jr.

    1983-09-01

    Numerical studies were carried out to investigate the gross structure of flow in cylindrical combustors. The combustor configurations studied are variations of a working design used at the University of Tennessee Space Institute to burn pulverized coal at temperatures in excess of 3000K for generation of a plasma feeding a magnetohydrodynamic channel. The numerical studies were conducted for an isothermal fluid; the main objective of the calculations was to study the effect of the oxidant injection pattern on the gross structure of recirculating flows within the combustor. The calculations illustrate the basic features of the flow in combustors of this type and suggest implications for the injection of coal and oxidizer in this type of combustor.

  14. Exergetic performance analysis of a recirculating aquaculture system

    Energy Technology Data Exchange (ETDEWEB)

    Kucuk, Haydar [Mechanical Engineering Department, Guemueshane University, 29000 Guemueshane (Turkey); Midilli, Adnan [Energy Division, Mechanical Engineering Department. Nigde University, 51000 Nigde (Turkey); Oezdemir, Atilla; Cakmak, Eyuep [Central Fisheries Research Institute, Ministry of Agricultural and Rural Affairs, Trabzon (Turkey); Dincer, Ibrahim [Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, Ont. (Canada)

    2010-05-15

    This paper examines exergetic aspects of a Recirculation Aquaculture System (RAS) for Black Sea trout (Salmo trutta labrax) fingerling rearing at the Trabzon Central Fisheries Research Institute, Turkey. In its thermodynamic analysis, each component of the RAS is treated as a steady-state steady flow system and its exergetic efficiencies are studied. In addition, the following parameters are measured and recorded in experiments: the mass flow rates, inlet and outlet temperatures and of the system components, surrounding temperatures, and electrical work utilized by the components in the RAS. Based on these experimental data, inlet and outlet exergy values, exergy losses, and exergetic efficiencies of each component in the system are determined to assess their performance. Moreover, the overall system exergy efficiency is determined. The results show that exergy efficiencies of the system components are highly affected by varying input exergy flows as a function of the surrounding temperature and chiller's operating period. (author)

  15. The Role of Filtration in Maintaining Clean Heat Exchanger Coils

    Energy Technology Data Exchange (ETDEWEB)

    Li Yang; James E. Braun; Eckhard A. Groll

    2004-06-30

    The main purpose of the study was to investigate the role of filtration in maintaining clean heat exchanger coils and overall performance. Combinations of 6 different levels of filtration (MERV 14, 11, 8, 6, 4, and no filter) and 4 different coils (an eight-row lanced-fin coil, HX8L), (an eight-row wavy-fin coil, HX8W), (a four-row lanced-fin coil, HX4L) and (a two-row lanced-fin coil, HX2L) were tested at 4 different air velocities (1.52, 2.03, 2.54,3.05 m/s (300, 400, 500, 600 ft/min)). The fouled conditions were obtained after injection of 600 grams of ASHRAE standard dust upstream of the filter/coil combination. This magnitude of dust is representative of a year of normal operation for an air conditioning system. The air-side pressure drops of the coils and filters and air-side heat transfer coefficients of the coils were determined from the measurements under the clean and fouled conditions. Depending upon the filter and coil test, the coil pressure drops increased in the range of 6%-30% for an air velocity at 2.54 m/s (500 ft/min). The impact was significantly greater for tests performed without a filter. The largest relative effect of fouling on pressure drop occurs for coils with fewer rows and having lanced fins. Coils with a greater number of rows can hold more dust so that a fixed amount of dust has a relatively smaller impact. The impact of fouling on air-side heat transfer coefficients was found to be relatively small. In some cases, heat transfer was actually enhanced due to additional turbulence caused by the presence of dust. The experimental results for pressure drops and heat transfer coefficients were correlated and the correlations were implemented within computer models of prototypical rooftop air conditioners and used to evaluate the impact of fouling on cooling capacity and EER. The equipment cooling capacity is reduced with fouling primarily because of a decrease in air flow due to the increase pressure drop rather than due to changes in h

  16. Filtration theory using computer simulations

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, W.; Corey, I. [Lawrence Livermore National Lab., CA (United States)

    1997-08-01

    We have used commercially available fluid dynamics codes based on Navier-Stokes theory and the Langevin particle equation of motion to compute the particle capture efficiency and pressure drop through selected two- and three-dimensional fiber arrays. The approach we used was to first compute the air velocity vector field throughout a defined region containing the fiber matrix. The particle capture in the fiber matrix is then computed by superimposing the Langevin particle equation of motion over the flow velocity field. Using the Langevin equation combines the particle Brownian motion, inertia and interception mechanisms in a single equation. In contrast, most previous investigations treat the different capture mechanisms separately. We have computed the particle capture efficiency and the pressure drop through one, 2-D and two, 3-D fiber matrix elements. 5 refs., 11 figs.

  17. Oral bioavailability and enterohepatic recirculation of otilonium bromide in rats.

    Science.gov (United States)

    Shin, Beom Soo; Kim, Jung Jun; Kim, John; Hu, Sul Ki; Kim, Hyoung Jun; Hong, Seok Hyun; Kim, Han Kyung; Lee, Hye Suk; Yoo, Sun Dong

    2008-01-01

    This study was conducted to examine the oral bioavailability and the possibility of enterohepatic recirculation of otilonium bromide in rats. A sensitive LC/MS/MS assay (LLOQ 0.5 ng/mL) was developed for the determination of otilonium and applied to i.v. and oral administration studies in bile duct cannulated (BDC) and non-BDC rats. After i.v. injection to BDC rats (1 mg/ kg as otilonium), average t(1/2), CL, Vz and AUC were 7.9 +/- 1.9 h, 8.7 +/- 3.1 mL/min/kg, 5.7 +/- 1.4 L/kg and 2,088 +/- 676 ng h/mL, respectively, and these values were comparable to those found in non-BDC rats. The percentages of i.v. dose excreted unchanged in bile and urine in BDC rats were 11.6 +/- 3.0 and 3.1 +/- 0.7%, respectively. Upon oral administration to non-BDC rats (20 mg/kg as otilonium), t(1/2), Cmax, Tmax and AUC were 6.4 +/- 1.3 h, 182.8 +/- 44.6 ng/mL, 1.9 +/- 1.6 h and 579 +/- 113 ng h/mL, respectively. The absolute oral bioavailability was low (1.1%), while the drug was preferentially distributed to gastrointestinal tissues. A secondary peak was observed in the serum concentration-time profiles in non-BDC rats following both i.v. and oral administration, indicating that otilonium bromide was subject to enterohepatic recirculation.

  18. Recirculation of the Canary Current in fall 2014

    Science.gov (United States)

    Hernández-Guerra, Alonso; Espino-Falcón, Elisabet; Vélez-Belchí, Pedro; Dolores Pérez-Hernández, M.; Martínez-Marrero, Antonio; Cana, Luis

    2017-10-01

    Hydrographic measurements together with Ship mounted Acoustic Doppler Current Profilers and Lowered Acoustic Doppler Current Profilers (LADCP) obtained in October 2014 are used to describe water masses, geostrophic circulation and mass transport of the Canary Current System, as the Eastern Boundary of the North Atlantic Subtropical Gyre. Geostrophic velocities are adjusted to velocities from LADCP data to estimate an initial velocity at the reference layer. The adjustment results in a northward circulation at the thermocline layers over the African slope from an initial convergent flow. Final reference velocities and consequently absolute circulation are estimated from an inverse box model applied to an ocean divided into 13 neutral density layers. This allows us to evaluate mass fluxes consistent with the thermal wind equation and mass conservation. Ekman transport is estimated from the wind data derived from the Weather Research and Forecasting model. Ekman transport is added to the first layer and adjusted with the inverse model. The Canary Current located west of Lanzarote Island transports to the south a mass of - 1.5 ± 0.7 Sv (1 Sv = 106 m3 s- 1 ≈ 109 kg s- 1) of North Atlantic Central Water at the surface and thermocline layers ( 0-700 m). In fall 2014, hydrographic data shows that the Canary Current in the thermocline (below at about 80 m depth to 700 m) recirculates to the north over the African slope and flows through the Lanzarote Passage. At intermediate layers ( 700-1400 m), the Intermediate Poleward Undercurrent transports northward a relatively fresh Antarctic Intermediate Water in the range of 0.8 ± 0.4 Sv through the Lanzarote Passage and west of Lanzarote Island beneath the recirculation of the Canary Current.

  19. High gradient magnetic filtration of cupric oxide and fly ash particles

    Energy Technology Data Exchange (ETDEWEB)

    Lua, A.C. [Nanyang Technological University (Singapore). School of Mechanical and Production Engineering

    1996-12-31

    High gradient magnetic filtration (HGMF) tests have been carried out on cupric oxide particles and power plant fly ash which were dispersed in air streams. An experimental test rig was set up to conduct these tests. Results showed that for cupric oxide particles, filtration efficiencies of up to 95% were obtained for submicron sizes with dust loadings of up to 0.36 time the matrix volume. For fly ash, filtration efficiencies of up to 65% were obtained for submicron particles. However, all particle sizes showed progressive deterioration in efficiencies with loading. At the end of the test, the matrix had collected 0.52 times its own mass of fly ash. 2 refs., 7 figs.

  20. Effectiveness of Floating Micro-Bead Bio-Filter for Ornamental Fish in a Re-Circulating Aquaculture System

    Directory of Open Access Journals (Sweden)

    R Fadhil

    2011-01-01

    Full Text Available Bio-filtration has been widely used in re-circulating aquaculture system to remove waste and to convert toxic ammonia andnitrite into safe end products ornamental fish and other aquatic organisms. However, the study of micro-bead usage as the filter medium has not yet been broadened and thoroughly developed. Therefore, the aim of this study is to construct a biological filter made from polyethylene micro-bead as the filter medium and to analyze its effectiveness in removingwaste as well as in converting the toxic organic matter into stable substances. The bio-filter was constructed under a rotational molding process. The tubes, hoses, and piping were made from polyvinyl chloride (PVC while the fasteners were made from stainless steel and other non-corrosive materials. The effectiveness of this bio-filter was measured by using biochemical oxygen demand (BOD and total suspended solids (TSS analysis. Results indicated that this bio-filter is efficient enough to remove suspended solids and BOD. Therefore, this floating micro-bead bio-filter can be used in aquaculture systems.

  1. SELECTIVE NOx RECIRCULATION FOR STATIONARY LEAN-BURN NATURAL GAS ENGINES

    Energy Technology Data Exchange (ETDEWEB)

    Nigel Clark; Gregory Thompson; Richard Atkinson; Chamila Tissera; Matt Swartz; Emre Tatli; Ramprabhu Vellaisamy

    2005-01-01

    The research program conducted at the West Virginia University Engine and Emissions Research Laboratory (EERL) is working towards the verification and optimization of an approach to remove nitric oxides from the exhaust gas of lean burn natural gas engines. This project was sponsored by the US Department of Energy, National Energy Technology Laboratory (NETL) under contract number: DE-FC26-02NT41608. Selective NOx Recirculation (SNR) involves three main steps. First, NOx is adsorbed from the exhaust stream, followed by periodic desorption from the aftertreatment medium. Finally the desorbed NOx is passed back into the intake air stream and fed into the engine, where a percentage of the NOx is decomposed. This reporting period focuses on the NOx decomposition capability in the combustion process. Although researchers have demonstrated NOx reduction with SNR in other contexts, the proposed program is needed to further understand the process as it applies to lean burn natural gas engines. SNR is in support of the Department of Energy goal of enabling future use of environmentally acceptable reciprocating natural gas engines through NOx reduction under 0.1 g/bhp-hr. The study of decomposition of oxides of nitrogen (NOx) during combustion in the cylinder was conducted on a 1993 Cummins L10G 240 hp lean burn natural gas engine. The engine was operated at different air/fuel ratios, and at a speed of 800 rpm to mimic a larger bore engine. A full scale dilution tunnel and analyzers capable of measuring NOx, CO{sub 2}, CO, HC concentrations were used to characterize the exhaust gas. Commercially available nitric oxide (NO) was used to mimic the NOx stream from the desorption process through a mass flow controller and an injection nozzle. The same quantity of NOx was injected into the intake and exhaust line of the engine for 20 seconds at various steady state engine operating points. NOx decomposition rates were obtained by averaging the peak values at each set point minus

  2. The Glomerular Filtration Barrier: Components and Crosstalk

    Directory of Open Access Journals (Sweden)

    Madhav C. Menon

    2012-01-01

    Full Text Available The glomerular filtration barrier is a highly specialized blood filtration interface that displays a high conductance to small and midsized solutes in plasma but retains relative impermeability to macromolecules. Its integrity is maintained by physicochemical and signalling interplay among its three core constituents—the glomerular endothelial cell, the basement membrane and visceral epithelial cell (podocyte. Understanding the pathomechanisms of inherited and acquired human diseases as well as experimental injury models of this barrier have helped to unravel this interdependence. Key among the consequences of interference with the integrity of the glomerular filtration barrier is the appearance of significant amounts of proteins in the urine. Proteinuria correlates with kidney disease progression and cardiovascular mortality. With specific reference to proteinuria in human and animal disease phenotypes, the following review explores the roles of the endothelial cell, glomerular basement membrane, and the podocyte and attempts to highlight examples of essential crosstalk within this barrier.

  3. Development Study of Turbulent Kappa-Epsilon Model for Recirculation flow III : Two Dimension Recirculation Flow in a Reservoir

    Directory of Open Access Journals (Sweden)

    M. Syahril B. Kusuma

    2009-05-01

    Full Text Available An assessment of recirculation flow in Jatiluhur reservoir is conducted based on two dimensions turbulent K-e model. The numerical model was developed using finite difference method where hydrodynamic equation was solved by the combination of Mc Cormack and splitting methods. The K-e equation is solved using quickest scheme in convection term, central scheme in diffusion term and Euler scheme in reaction term. The simulations were done for maximum incoming flow during the rainy season and the dry season. Model results for the rainy season case have shown good agreement with those found by field measurement. The rainy season case generated a much recirculted flow and higher concentration of DO in the reservoir than that of the dry season case. Denser grid and high courant number is needed to avoid it from becoming oscillating and unstable and for achieving a more accurate results for the case with less average velocity.

  4. Maize genome sequencing by methylation filtration.

    Science.gov (United States)

    Palmer, Lance E; Rabinowicz, Pablo D; O'Shaughnessy, Andrew L; Balija, Vivekanand S; Nascimento, Lidia U; Dike, Sujit; de la Bastide, Melissa; Martienssen, Robert A; McCombie, W Richard

    2003-12-19

    Gene enrichment strategies offer an alternative to sequencing large and repetitive genomes such as that of maize. We report the generation and analysis of nearly 100,000 undermethylated (or methylation filtration) maize sequences. Comparison with the rice genome reveals that methylation filtration results in a more comprehensive representation of maize genes than those that result from expressed sequence tags or transposon insertion sites sequences. About 7% of the repetitive DNA is unmethylated and thus selected in our libraries, but potentially active transposons and unmethylated organelle genomes can be identified. Reverse transcription polymerase chain reaction can be used to finish the maize transcriptome.

  5. The Perspective of Riverbank Filtration in China

    Science.gov (United States)

    Li, J.; Teng, Y.; Zhai, Y.; Zuo, R.

    2014-12-01

    Sustainable drinking water supply can affect the health of people, and the surrounding ecosystems. According to statistics of the monitoring program of drinking water sources in 309 at or above prefecture level of China in 2013, the major pollutants index were total phosphorus, ammonia and manganese in surface drinking water sources, respectively, iron, ammonia and manganese in groundwater drinking water sources, respectively. More than 150 drinking water emergency environmental accidents happened since 2006, 52 of these accidents led to the disruption of water supply in waterworks, and a population of over ten million were affected. It indicated that there is a potential risk for people's health by the use of river water directly and it is necessary to require alternative techniques such as riverbank filtration for improving the drinking water quality. Riverbank filtration is an inexpensive natural process, not only smoothing out normal pollutant concentration found in surface water but also significantly reducing the risk from such emergency events as chemical spill into the river. Riverbank filtration technique has been used in many countries more than 100 years, including China. In China, in 1950s, the bank infiltration technique was first applied in northeast of China. Extensive bank infiltration application was conducted in 1980s, and more than 300 drinking water sources utilities bank infiltration established mainly near the Songhua River Basin, the Yellow River Basin, Haihe River Basin. However, the comparative lack of application and researches on riverbank filtration have formed critical scientific data gap in China. As the performance of riverbank filtration technique depend on not only the design and setting such as well type, pumping rate, but also the local hydrogeology and environmental properties. We recommend more riverbank filtration project and studies to be conducted to collect related significant environmental geology data in China

  6. Salt disposition alternatives filtration at SRTC

    Energy Technology Data Exchange (ETDEWEB)

    Walker, B. W.; Hobbs, D.

    2000-01-27

    Several of the prospective salt disposition alternative technologies require a monosodium titanate (MST) contact to remove strontium and actinides from inorganic salt solution feedstock. This feedstock also contains sludge solids from waste removal operations and may contain defoamers added in the evaporator systems. Filtration is required to remove the sludge and MST solids before sending the salt solution for further processing. This report describes testing performed using the Parallel Theological Experimental Filter (PREF). The PREF contains two single tube Mott sintered metal crossflow filters. For this test one filter was isolated so that the maximum velocities could be achieved. Previous studies showed slurries of MST and sludge in the presence of sodium tetraphenylborate (NaTPB) were filterable since the NaTPB slurry formed a filter cake which aided in removing the smaller MST and sludge particles. Some of the salt disposition alternative technologies do not use NaTPB raising the question of how effective crossflow filtration is with a feed stream containing only sludge and MST. Variables investigated included axial velocity, transmembrane pressure, defoamer effects, and solids concentration (MST and sludge). Details of the tests are outlined in the technical report WSRC-RP-98-O0691. Key conclusions from this study are: (1) Severe fouling of the Mott sintered metal filter did not occur with any of the solutions filtered. (2) The highest fluxes, in the range of .46 to 1.02 gpm/f{sup 2}, were obtained when salt solution decanted from settled solids was fed to the filter. These fluxes would achieve 92 to 204 gpm filtrate production for the current ITP filters. The filtrate fluxes were close to the flux of 0.42 gpm/f{sup 2} reported for In Tank Precipitation Salt Solution by Morrisey. (3) For the range of solids loading studied, the filter flux ranged from .04 to .17 gpm/f{sup 2} which would result in a filtrate production rate of 9 to 31 gpm for the current HP

  7. Industrial investigations of the liquid steel filtration

    Directory of Open Access Journals (Sweden)

    K. Janiszewski

    2014-07-01

    Full Text Available Hitherto existing investigations concerning the ceramic filter use in the steel making processes have given good results. The obtained results of filtration have proved that this method may be used as an effective and cheap way of steel filtration from non-metallic inclusions. Placing filters in the tundish is the best location considering the limitation of the possibility of secondary pollution of steel. Yet, the results presented in this paper, of an experiment prepared and carried out in the industrial environment, are the only positive results obtained, which are connected with so much quantities of liquid steel processed with use of the multi-hole ceramic filters.

  8. Projective Dimension in Filtrated K-Theory

    DEFF Research Database (Denmark)

    Bentmann, Rasmus Moritz

    2013-01-01

    Under mild assumptions, we characterise modules with projective resolutions of length n∈N in the target category of filtrated K-theory over a finite topological space in terms of two conditions involving certain Tor -groups. We show that the filtrated K-theory of any separable C∗dash-algebra over...... any topological space with at most four points has projective dimension 2 or less. We observe that this implies a universal coefficient theorem for rational equivariant KK-theory over these spaces. As a contrasting example, we find a separable C∗dash-algebra in the bootstrap class over a certain five...

  9. Projective Dimension in Filtrated K-Theory

    DEFF Research Database (Denmark)

    Bentmann, Rasmus Moritz

    2013-01-01

    any topological space with at most four points has projective dimension 2 or less. We observe that this implies a universal coefficient theorem for rational equivariant KK-theory over these spaces. As a contrasting example, we find a separable C∗dash-algebra in the bootstrap class over a certain five......-point space, the filtrated K-theory of which has projective dimension 3. Finally, as an application of our investigations, we exhibit Cuntz-Krieger algebras which have projective dimension 2 in filtrated K-theory over their respective primitive spectrum....

  10. Mechanisms of pressure filtration of liquid aluminum alloys

    Science.gov (United States)

    Cao, X.

    2006-12-01

    The Prefil Footprinter, a portable pressure filtration instrument, is usually used to detect the quality of liquid aluminum alloys. However, no investigations have ever been done to calculate the cake resistance to date. Based on the identification and classification of flow behavior using the first derivative method for filtrate mass vs filtration time curves, conventional filtration equations are successfully employed to understand the filtration behaviors. From the analyses of the variations of cake resistance with filtration time, the filtration mechanisms are discussed in detail over the different filtration stages. During the steady stage, either incompressible or compressible cake mode is the main mechanism. At the initial and terminal transient stages, however, deep-bed filtration, complete straining, and solidification clogging may appear. Solid inclusions in liquid metal have significant influence on the cake structures and properties. Some important issues related to the heterogeneity of filter media and test methodology are highlighted in this work.

  11. Dedicated breast CT: effect of adaptive filtration on dose distribution

    CERN Document Server

    Shikhaliev, Polad M

    2016-01-01

    Purpose: The purpose of the work was experimental investigations of the breast dose distributions with adaptive filtration. Adaptive filtration reduces detector dynamic range and improves image quality. The adaptive filter with predetermined shape is placed at the x-ray beam such that the x-ray intensity at the detector surface is flat. However, adaptive filter alters the mean dose to the breast, as well as volume distribution of the dose. Methods: The dose was measured using a 14 cm diameter cylindrical acrylic breast phantom. An acrylic adaptive filter was fabricated to match the 14 cm diameter of the phantom. The dose was measured using ion chamber inserted into holes distributed along the radius of the phantom from the center to the edge. The radial distribution of dose was measured and fitted by an analytical function and the volume distribution and mean value of dose was calculated. The measurements were performed at 40, 60, 90, and 120 kVp tube voltages and 6.6 mGy air kerma. Results: The adaptive filt...

  12. Carbon Nanotube Membranes: Synthesis, Properties, and Future Filtration Applications

    Directory of Open Access Journals (Sweden)

    Md. Harun-Or Rashid

    2017-05-01

    Full Text Available Over the course of the past decade, there has been growing interest in the development of different types of membranes composed of carbon nanotubes (CNTs, including buckypapers and composite materials, for an ever-widening range of filtration applications. This article provides an overview of how different types of CNT membranes are prepared and the results obtained from investigations into their suitability for different applications. The latter involve the removal of small particles from air samples, the filtration of aqueous solutions containing organic compounds and/or bacteria, and the separation of individual liquids present in mixtures. A growing number of reports have demonstrated that the incorporation of CNTs into composite membranes confers an improved resistance to fouling caused by biomacromolecules and bacteria. These results are discussed, along with evidence that demonstrates it is possible to further reduce fouling by taking advantage of the inherent conductivity of composite membranes containing CNTs, as well as by using different types of electrochemical stimuli.

  13. Intermittent filtration of bacteria and colloids in porous media

    Science.gov (United States)

    Auset, Maria; Keller, Arturo A.; Brissaud, François; Lazarova, Valentina

    2005-09-01

    Intermittent filtration through porous media used for water and wastewater treatment can achieve high pathogen and colloid removal efficiencies. To predict the removal of bacteria, the effects of cyclic infiltration and draining events (transient unsaturated flow) were investigated. Using physical micromodels, we visualized the intermittent transport of bacteria and other colloids in unsaturated porous media. Column experiments provided quantitative measurements of the phenomena observed at the pore scale. Tagged Escherichia coli and a conservative tracer (NaI) were introduced in an initial pulse into a 1.5 m sand column. Subsequent hydraulic flushes without tagged bacteria or tracer were repeated every 4 hours for the next 4 days, during which outflow concentrations were monitored. Breakthrough behavior between colloids and dissolved tracer differed significantly, reflecting the differences in transport processes. Advancement of the wetting front remobilized bacteria which were held in thin water films, attached to the air-water interface (AWI), or entrapped in stagnant pore water between gas bubbles. In contrast, the tracer was only remobilized by diffusion from immobile to mobile water. Remobilization led to successive concentration peaks of bacteria and tracer in the effluent but with significant temporal differences. Observations at the pore-scale indicated that the colloids were essentially irreversibly attached to the solid-water interface, which explained to some extent the high removal efficiency of microbes in the porous media. Straining, cluster filtration, cell lysis, protozoa grazing, and bacteriophage parasitism could also contribute to the removal efficiency of bacteria.

  14. Sulfur recirculation for increased electricity production in Waste-to-Energy plants.

    Science.gov (United States)

    Andersson, Sven; Blomqvist, Evalena W; Bäfver, Linda; Jones, Frida; Davidsson, Kent; Froitzheim, Jan; Karlsson, Martin; Larsson, Erik; Liske, Jesper

    2014-01-01

    Sulfur recirculation is a new technology for reducing boiler corrosion and dioxin formation. It was demonstrated in full-scale tests at a Waste to Energy plant in Göteborg (Sweden) during nearly two months of operation. Sulfur was recirculated as sulfuric acid from the flue gas cleaning back to the boiler, thus creating a sulfur loop. The new technology was evaluated by extensive measurement campaigns during operation under normal conditions (reference case) and operation with sulfur recirculation. The chlorine content of both fly ash and boiler ash decreased and the sulfur content increased during the sulfur recirculation tests. The deposit growth and the particle concentration decreased with sulfur recirculation and the dioxin concentration (I-TEQ) of the flue gas was reduced by approximately 25%. Sulfuric acid dew point measurements showed that the sulfuric acid dosage did not lead to elevated SO3 concentrations, which may otherwise induce low temperature corrosion. In the sulfur recirculation corrosion probe exposures, the corrosion rate decreased for all tested materials (16Mo3, Sanicro 28 and Inconel 625) and material temperatures (450 °C and 525 °C) compared to the reference exposure. The corrosion rates were reduced by 60-90%. Sulfur recirculation prevented the formation of transition metal chlorides at the metal/oxide interface, formation of chromate and reduced the presence of zinc in the corrosion products. Furthermore, measured corrosion rates at 525 °C with sulfur recirculation in operation were similar or lower compared to those measured at 450 °C material temperature in reference conditions, which corresponds to normal operation at normal steam temperatures. This implies that sulfur recirculation allows for higher steam data and electricity production without increasing corrosion.

  15. Long term/low dose formalin exposure to small-scale recirculation aquaculture systems

    DEFF Research Database (Denmark)

    Pedersen, Lars-Flemming; Pedersen, Per Bovbjerg; Nielsen, Jeppe L.

    2010-01-01

    Repetitive long term formalin application at low dose was investigated to determine the effect on formaldehyde removal rate, biofilter nitrification and the microbial composition in small-scale recirculation aquaculture biofilters. Six pilot-scale recirculation aquaculture systems holding rainbow...... Nitrobacter sp. was not detected. The relative abundances of AOB and NOB in the untreated system were generally higher compared to the system exposed to formalin. Low dose formalin in recirculated aquaculture systems proved to be a possible treatment strategy, as the effect on nitrification was minimal. Since...

  16. Aerosol filtration - performance of filter media; Filtration des aerosols - performances des medias filtrants

    Energy Technology Data Exchange (ETDEWEB)

    Bemer, D.; Regnier, R. [Institut National de Recherche et de Securite (INRS), Dept. Ingenierie des Procedes, 75 - Paris (France); Calle, S.; Thomas, D.; Simon, X.; Appert-Collin, J.Ch. [Centre National de la Recherche Scientifique (CNRS), Lab. des Sciences du Genie Chimique de Nancy, 54 - Vandoeuvre-les-Nancy (France)

    2006-03-15

    Set up in 2000, the Laboratoire de Filtration des Aerosols in Nancy (LFA), associating research teams from INRS (Institut National de Recherche et de Securite and LSGC (Laboratoire des Sciences du Genie Chimique - CNRS), has been commissioned to provide expertise in the aerosol filtration field to both CRAM (Caisse Regionale de l'Assurance Maladie) prevention specialists and industrialists. Following a theoretical review of fibre medium filtration, this paper summarises the different actions undertaken by the LFA: filter performance during clogging with liquid and solid aerosols, modelling, pneumatic unclogging of baghouse dust collectors, influence of micro-leaks, etc. (authors)

  17. Prevention of febrile nonhemolytic transfusion reaction with leucocyte filtrated concentrates

    Institute of Scientific and Technical Information of China (English)

    ZHAO Shu-ming; XIANG Guo-chun; ZHANG Jia-si; CHENG Xiao-ling; LI Ru-qing

    2002-01-01

    Objective: To assess the clinical efficiency of the transfusion of leucocyte filtrated RBC concentrates to prevent febrile nonhemolytic transfusion reactions (FNHTRs). Methods: One hundred patients with liver cirrhosis, gastric ulcer or cancer were subjected to receive RBC concentrates after leucocyte filtration.Another 50 patients with similar diseases were selected to receive non-filtrated RBC concentrates. The incidence of FNHTRs in all patients was investigated. Results: There was no FNHTR in 100 transfusions with leucocyte filtrated RBC concentrates, while FNHTRs occurred in 8 of 50 patients with non-filtrated RBC concentrates, with the incidence of 160%. Conclusion: FNHTRs to RBC transfusion can be prevented with leucocyte filtration.

  18. Plasma discharge self-cleaning filtration system

    Science.gov (United States)

    Cho, Young I.; Fridman, Alexander; Gutsol, Alexander F.; Yang, Yong

    2014-07-22

    The present invention is directed to a novel method for cleaning a filter surface using a plasma discharge self-cleaning filtration system. The method involves utilizing plasma discharges to induce short electric pulses of nanoseconds duration at high voltages. These electrical pulses generate strong Shockwaves that disintegrate and dislodge particulate matter located on the surface of the filter.

  19. Filtration of engineered nanoparticles using porous membranes

    NARCIS (Netherlands)

    Trzaskus, Krzystof

    2016-01-01

    The research presented in this thesis aims at providing a better understanding of the fundamental aspects responsible for nanoparticle removal and fouling development during filtration of engineered nanoparticles. The emphasis is put on the role of interparticle interactions in the feed solution,

  20. Organic micropollutant removal during river bank filtration

    NARCIS (Netherlands)

    Bertelkamp, C.

    2015-01-01

    This study investigated the factors influencing the main removal mechanisms (adsorption and biodegradation) for organic micropollutant (OMP) removal during river bank filtration (RBF) and the possibility of developing a predictive model of this process for OMP removal during RBF. Chapter 2 analysed

  1. Advances in hot gas filtration technology

    Energy Technology Data Exchange (ETDEWEB)

    Weber, C.

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

  2. Using Digital Filtration for Hurst Parameter Estimation

    Directory of Open Access Journals (Sweden)

    J. Prochaska

    2009-06-01

    Full Text Available We present a new method to estimate the Hurst parameter. The method exploits the form of the autocorrelation function for second-order self-similar processes and is based on one-pass digital filtration. We compare the performance and properties of the new method with that of the most common methods.

  3. Development of an Indexing Media Filtration System for Long Duration Space Missions

    Science.gov (United States)

    Agui, Juan H.; Vijayakumar, R.

    2013-01-01

    The effective maintenance of air quality aboard spacecraft cabins will be vital to future human exploration missions. A key component will be the air cleaning filtration system which will need to remove a broad size range of particles including skin flakes, hair and clothing fibers, other biological matter, and particulate matter derived from material and equipment wear. In addition, during surface missions any extraterrestrial planetary dust, including dust generated by near-by ISRU equipment, which is tracked into the habitat will also need to be managed by the filtration system inside the pressurized habitat compartments. An indexing media filter system is being developed to meet the demand for long-duration missions that will result in dramatic increases in filter service life and loading capacity, and will require minimal crew involvement. These features may also benefit other closed systems, such as submarines, and remote location terrestrial installations where servicing and replacement of filter units is not practical. The filtration system consists of three stages: an inertial impactor stage, an indexing media stage, and a high-efficiency filter stage, packaged in a stacked modular cartridge configuration. Each stage will target a specific range of particle sizes that optimize the filtration and regeneration performance of the system. An 1/8th scale and full-scale prototype of the filter system have been fabricated and have been tested in the laboratory and reduced gravity environments that simulate conditions on spacecrafts, landers and habitats. Results from recent laboratory and reducegravity flight tests data will be presented.

  4. MULTILAYER POROUS COMPOSITE FROM WASTE GLASS FOR WATER FILTRATION

    Directory of Open Access Journals (Sweden)

    M. P. Aji

    2015-07-01

    Full Text Available Multilayer porous composite have been produced through the heating process at temperature T=700oC for 2.5 h. Single layered porous composite was made with a varied mass percentage of from PEG polymer  1% to 10%. Double-layered porous composite were made by the arrangement of porosity (4:3%, (4:2% and (3:2%, while the three-layers porous composite have an arrangement (4:3:2%. Performance of multilayer porous composite for water filtration with pollutants of methylene blue 100 ppm was estimated from the absorbance spectrum. Rejection of methylene blue pollutants from single layered porous composite increases when the fraction of PEG polymer tend to be smaller in the matrix. Meanwhile, the double layered porous composite has a degradation of methylene blue pollutants are better than one layer. Triple layered porous composite have good performance for the water filtration where all the pollutants of methylene blue be able to be filtered.   Komposit pori berlapis telah dihasilkan dengan proses pemanasan pada temperatur T=700oC selama 2.5 jam. Komposit pori satu lapis dibuat dengan variasi persen massa polimer PEG 1% hingga 10%. Komposit pori dua lapis dibuat dengan susunan porositas (4:3%, (4:2% dan (3:2%, sedangkan komposit pori tiga lapis memiliki susunan porositas (4:3:2%. Kinerja komposit pori berlapis untuk filter air dengan polutan methylene blue 100 ppm diestimasi dari spektrum absorbansi. Rejeksi polutan methylene blue dari komposit pori satu lapis meningkat saat fraksi polimer PEG cenderung lebih kecil dalam matrik komposit. Sedangkan, komposit pori dua lapis memiliki kemampuan untuk degradasi polutan methylene blue yang lebih baik dari satu lapis. Komposit pori tiga lapis memiliki kinerja yang baik untuk filter air dimana seluruh polutan methylene blue mampu disaring. 

  5. Duckweed Lemna minor (Liliopsida, Lemnaceae) as a natural biofilter in brackish and fresh closed recirculating systems

    National Research Council Canada - National Science Library

    Tharwat S. Nashashibi; Mutaz A. Al-Qutob

    2012-01-01

    This study attempted to assess the potential use of common duckweed Lemna minor asnatural biofilter in brackish closed recirculating systems of 4 g/L salinity and to evaluate the effect ofsalinities...

  6. High-Power Laser Pulse Recirculation for Inverse Compton Scattering-Produced Gamma-Rays

    Energy Technology Data Exchange (ETDEWEB)

    Jovanovic, I; Shverdin, M; Gibson, D; Brown, C

    2007-04-17

    Inverse Compton scattering of high-power laser pulses on relativistic electron bunches represents an attractive method for high-brightness, quasi-monoenergetic {gamma}-ray production. The efficiency of {gamma}-ray generation via inverse Compton scattering is severely constrained by the small Thomson scattering cross section. Furthermore, repetition rates of high-energy short-pulse lasers are poorly matched with those available from electron accelerators, resulting in low repetition rates for generated {gamma}-rays. Laser recirculation has been proposed as a method to address those limitations, but has been limited to only small pulse energies and peak powers. Here we propose and experimentally demonstrate an alternative method for laser pulse recirculation that is uniquely capable of recirculating short pulses with energies exceeding 1 J. Inverse Compton scattering of recirculated Joule-level laser pulses has a potential to produce unprecedented peak and average {gamma}-ray brightness in the next generation of sources.

  7. Considerations upon energetic efficiency of a recirculating aquatic system (RAS for super intensive fish culture

    Directory of Open Access Journals (Sweden)

    Petru David

    2009-04-01

    Full Text Available The efficiency of the aquaculture using recirculating systems depends on many factors among which the most important it is the energy consumption of the system. To assure a high levelenergy conservation in an aquatic recirculating system, the intensity of water recirculation must be maximized, but this leads to a increasing of the consumed energy for water circulation. That is why is required a rigorous analysis for the energetic consumption for a system of this type and establishment of optimum solutions to minimize the consumption. This paperwork presents a detailed analysis of the energy consumption for a recirculating aquatic system for fish breeding, as well as considerations and solutions for optimization of the energy consumption.

  8. Applying rotary jet heads for mixing and mass transfer in a forced recirculation tank reactor system

    DEFF Research Database (Denmark)

    Nordkvist, Mikkel; Grotkjær, Thomas; Hummer, J.S.

    2003-01-01

    An approximation to an ideally mixed tank reactor can be obtained by vigorous stirring with mechanical mixers. For an aerated reactor the gas dispersion contributes to the mixing process. Mixing can also be achieved by recirculation of a portion of the liquid through either an internal...... or an external loop.In this study, we determine mixing times in water and CMC solutions and oxygen mass transfer coefficients in water for a tank reactor system where a small fraction of the total liquid volume is rapidly circulated through an external loop and injected through the nozzles of rotary jet heads...... at 1-9 bar gauge pressure into the bulk liquid. Liquid feed can be added to the bulk volume or it may be injected into the pressurized recirculation loop. Gas is always fed to the recirculation loop, and the heat of reaction is removed in a plate-type heat exchanger inserted in the recirculation loop...

  9. The influence of preliminary aerobic treatment on the efficacy of waste stabilisation under leachate recirculation conditions

    Directory of Open Access Journals (Sweden)

    Monika Suchowska-Kisielewicz

    2014-12-01

    Full Text Available This article presents the changes in the chemical composition of leachate and the concentrations and quantity of methane production in each individual decomposition phases, determined for untreated and after aerobic treatment of waste stabilised in anaerobic reactors with and without leachate recirculation. The research results demonstrate that leachate recirculation intensifies the decomposition of both aerobically treated and untreated waste. The methane production in the reactor with untreated, stabilised waste with recirculation was 28% higher; and in the reactor with aerobically treated waste, the methane production was 24% higher than in the reactors without recirculation. An important finding of the study is that aerobic treatment of waste prior to landfilling effectively reduces the quantity of pollutant emissions in leachate and biogas from waste and increases the availability for methane micro-organisms of organic substrates from difficult-to-decompose organic substances.

  10. Dietary carbohydrate composition can change waste production and biofilter load in recirculating aquaculture systems

    NARCIS (Netherlands)

    Meriac, A.; Eding, E.H.; Schrama, J.W.; Kamstra, A.; Verreth, J.A.J.

    2014-01-01

    This study investigated the effect of dietary carbohydrate composition on the production, recovery and degradability of fecal waste from rainbow trout (Oncorhynchus mykiss) in recirculating aquaculture systems (RAS). Dietary carbohydrate composition was altered by substituting starch with non-starch

  11. Energy Implications of In-Line Filtration in California

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Iain S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dickerhoff, Darryl [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Faulkner, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Turner, William J.N. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2013-02-01

    Occupant concern about indoor air quality (IAQ) issues has led to the increased use of more effective air filters in residential heating and cooling systems. This study performed measurements in ten California houses to determine the effects of changing filter performance and related characteristics on the energy use of the heating and cooling systems. Multiple filters were evaluated covering a wide range of filter effectiveness from simple low filtration fiberglass filters up to high efficiency filters that might be used by occupants concerned about IAQ. Sophisticated analysis and simulation tools used the field-testing results to determine filter impacts for a wide range of parameters and California climates. The results indicate that for MERV 10/11/13 filters the effects on energy use are moderate (<5%) over a wide range of performance conditions and climates. Using higher MERV 16 filters can lead to significantly increased energy use (>5%). The high airflow resistance of MERV 16 filters led to excess noise in some test houses from air bypassing the filter and the blower motor. Filter loading rates varied more from house to house than by MERV rating and overall were quite low in many of the homes. Filter related energy use does not need to be addressed for filters of MERV 10/11/13 and MERV 16 filters should only be used with low leakage tested ducts unless the filter is mounted at the blower compartment. MERV 16 filters should only be used if the filter area is sufficient to prevent noise issues and if the duct system has low air flow resistance and low leakage. Filters should be labeled for their air flow resistance, or static pressure at a particular flow rate, that would allow codes and standards to reference a particular performance specification and allow contractors and homeowners to make informed purchases.

  12. Design of a High-Reynolds Number Recirculating Water Tunnel

    Science.gov (United States)

    Daniel, Libin; Elbing, Brian

    2014-11-01

    An experimental fluid mechanics laboratory focused on turbulent boundary layers, drag reduction techniques, multiphase flows and fluid-structure interactions has recently been established at Oklahoma State University. This laboratory has three primary components; (1) a recirculating water tunnel, (2) a multiphase pipe flow loop, and (3) a multi-scale flow visualization system. The design of the water tunnel is the focus of this talk. The criteria used for the water tunnel design was that it had to produce a momentum-thickness based Reynolds number in excess of 104, negligible flow acceleration due to boundary layer growth, maximize optical access for use of the flow visualization system, and minimize inlet flow non-uniformity. This Reynolds number was targeted to bridge the gap between typical university/commercial water tunnels (103) and the world's largest water tunnel facilities (105) . These objectives were achieved with a 152 mm (6-inch) square test section that is 1 m long and has a maximum flow speed of 10 m/s. The flow non-uniformity was mitigated with the use of a tandem honeycomb configuration, a settling chamber and an 8.5:1 contraction. The design process that produced this final design will be presented along with its current status.

  13. OPTIMIZATION OF THE PROCESS OF DRYING THE FILTRATE DISTILLERY DREGS

    Directory of Open Access Journals (Sweden)

    A. A. Shevtsov

    2013-01-01

    Full Text Available The interactions of various factors affecting the process of drying the filtrate distillery dregs are investigated. Rational conditions for the process of drying the filtrate distillery dregs in a spray dryer are obtained.

  14. Internal filtration, filtration fraction, and blood flow resistance in high- and low-flux dialyzers.

    Science.gov (United States)

    Schneditz, Daniel; Zierler, Edda; Vanholder, Raymond; Eloot, Sunny

    2014-01-01

    It was the aim to examine the fluid flow in blood and dialysate compartments of highly permeable hollow fiber dialyzers where internal filtration contributes to solute removal but where excessive filtration bears a risk of cell activation and damage. Flow characteristics of high- (HF) and low-flux (LF) dialyzers were studied in lab-bench experiments using whole bovine blood. Measurements obtained under different operating conditions and under zero net ultrafiltration were compared to theoretical calculations obtained from a mathematical model. Experimental resistances in the blood compartment were within ±2% of those calculated from the model when dialysate was used as a test fluid. With whole blood, the experimental resistances in the blood compartment were only 81.8 ± 2.8% and 83.7 ± 4.3% of those calculated for the LF and HF dialyzer, respectively. Surprisingly, measured blood flow resistance slightly but significantly decreased with increasing flow rate (p filtration fraction, while overall internal filtration increased. The increase in internal filtration when increasing blood flow is associated with a beneficial reduction in internal filtration fraction. Concerns of increased hemoconcentration when increasing blood flow therefore appear to be unwarranted.

  15. Selective NOx Recirculation for Stationary Lean-Burn Natural Gas Engines

    Energy Technology Data Exchange (ETDEWEB)

    Nigel N. Clark

    2006-12-31

    Nitric oxide (NO) and nitrogen dioxide (NO2) generated by internal combustion (IC) engines are implicated in adverse environmental and health effects. Even though lean-burn natural gas engines have traditionally emitted lower oxides of nitrogen (NOx) emissions compared to their diesel counterparts, natural gas engines are being further challenged to reduce NOx emissions to 0.1 g/bhp-hr. The Selective NOx Recirculation (SNR) approach for NOx reduction involves cooling the engine exhaust gas and then adsorbing the NOx from the exhaust stream, followed by the periodic desorption of NOx. By sending the desorbed NOx back into the intake and through the engine, a percentage of the NOx can be decomposed during the combustion process. SNR technology has the support of the Department of Energy (DOE), under the Advanced Reciprocating Engine Systems (ARES) program to reduce NOx emissions to under 0.1 g/bhp-hr from stationary natural gas engines by 2010. The NO decomposition phenomenon was studied using two Cummins L10G natural gas fueled spark-ignited (SI) engines in three experimental campaigns. It was observed that the air/fuel ratio ({lambda}), injected NO quantity, added exhaust gas recirculation (EGR) percentage, and engine operating points affected NOx decomposition rates within the engine. Chemical kinetic model predictions using the software package CHEMKIN were performed to relate the experimental data with established rate and equilibrium models. The model was used to predict NO decomposition during lean-burn, stoichiometric burn, and slightly rich-burn cases with added EGR. NOx decomposition rates were estimated from the model to be from 35 to 42% for the lean-burn cases and from 50 to 70% for the rich-burn cases. The modeling results provided an insight as to how to maximize NOx decomposition rates for the experimental engine. Results from this experiment along with chemical kinetic modeling solutions prompted the investigation of rich-burn operating conditions

  16. Recirculation of Chilean copper smelting dust with high impurities contents to the smelting process

    Energy Technology Data Exchange (ETDEWEB)

    Sano, H.; Fujisawa, T. [Nagoya Univ., Nagoya (Japan). EcoTopia Science Inst.; Montenegro, V. [Nagoya Univ., Nagoya (Japan). Dept. of Materials Science and Engineering

    2007-07-01

    Dust generated during the copper smelting process is generally stabilized using hydrometallurgical methods as it contains high concentrations of arsenic. In this laboratory study, dust was recirculated during the smelting process in order to recover more copper and decrease dust emissions while recovering more copper. The behaviour of impurities and their influence on matte quality was also investigated. Industrial matte, flue dust, slag, and copper concentrates from a Chilean smelter were used as test materials. Dust recirculation tests were conducted in a simulated electric furnace. Off-gases were collected in a reaction tube, and the condensed volatile matter, slag, and matte phases were analyzed for their elemental content by inductively coupled plasma atomic emission spectrometry. The distribution of arsenic (As); antimony (Sb), bismuth (Bi), lead (Pb), and zinc (Zn) were investigated by varying the amounts of dust recirculating to the smelting stage with 21 per cent of the oxygen. Results showed that distributions of all analyzed elements increased with recirculation. It was concluded that copper can be recovered using the dust recirculation technique. However, impurities may limit the efficacy of the dust recirculation process. 6 refs., 3 tabs., 4 figs.

  17. 40 CFR 141.171 - Criteria for avoiding filtration.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Criteria for avoiding filtration. 141... PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration and Disinfection-Systems Serving 10,000 or More People § 141.171 Criteria for avoiding filtration. In addition to...

  18. 40 CFR 141.174 - Filtration sampling requirements.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Filtration sampling requirements. 141... PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration and Disinfection-Systems Serving 10,000 or More People § 141.174 Filtration sampling requirements. (a)...

  19. 40 CFR 141.71 - Criteria for avoiding filtration.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Criteria for avoiding filtration. 141... PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Filtration and Disinfection § 141.71 Criteria for avoiding filtration. A public water system that uses a surface water source must meet all...

  20. Origins of the poor filtration characteristics of wheat starch hydrolysates

    NARCIS (Netherlands)

    Matser, A.M.; Steeneken, P.A.M.

    1998-01-01

    The effects of wheat starch components on the filtration characteristics of wheat starch hydrolysates were investigated with a model-based approach. The filtration rate was not affected by the removal of the pentosans or by altering the conformation of the protein. On the other hand, the filtration

  1. Integrative filtration research and sustainable nanotechnology

    Institute of Scientific and Technical Information of China (English)

    Jing Wang; Drew Thompson; David Y.H.Pui

    2013-01-01

    With the wide applications of nanomaterials in an array of industries,more concerns are being raised about the occupational health and safety of nanoparticles in the workplace,and implications of nanotechnology on the environment and living systems.Studies on environmental,health and safety (EHS) issues of nanomaterials play a significant role in public acceptance,and eventual sustainability,of nanotechnology.We present research results on three aspects of the EHS studies:characterization and measurement of nanoparticles,nanoparticle emission and exposure at workplaces,and control and abatement of nanoparticle release using filtration technology.Measurement of nanoparticle agglomerates using a newly developed instrument,the Universal Nanoparticle Analyzer,is discussed.Nanoparticle emission and exposure measurement results for carbon nanotubes in the manufacture of nanocomposites and for silicon nanoparticles in their production at a pilot scale facility are presented.Filtration of nanoparticles and nanoparticle agglomerates are also studied.

  2. Ultrasonic filtration of industrial chemical solutions

    Science.gov (United States)

    Cosma, T.

    1974-01-01

    The practical results obtained as a result of filtering industrial chemical solutions under continuous flow conditions with the aid of an ultrasonic filter are presented. The main part of the assembly consists of an ultrasonic generator with an output power of about 400 W and the filtration assembly, in which there is a magnetostrictive amplifier constructed for 20.5 kHz. In addition to ensuring a continuous flow of filtered solution, ultrasonic filters can be replaced or cleaned at intervals of time that are 8-10 times greater than in the case of mechanical filters. They yield considerably better results as far as the size of the filtered particles is concerned. The parameters on which filtration quality depends are also presented.

  3. Breakthrough of cyanobacteria in bank filtration.

    Science.gov (United States)

    Pazouki, Pirooz; Prévost, Michèle; McQuaid, Natasha; Barbeau, Benoit; de Boutray, Marie-Laure; Zamyadi, Arash; Dorner, Sarah

    2016-10-01

    The removal of cyanobacteria cells in well water following bank filtration was investigated from a source water consisting of two artificial lakes (A and B). Phycocyanin probes used to monitor cyanobacteria in the source and in filtered well water showed an increase of fluorescence values demonstrating a progressive seasonal growth of cyanobacteria in the source water that were correlated with cyanobacterial biovolumes from taxonomic counts (r = 0.59, p cyanobacteria. Of cyanobacteria that passed through bank filtration, smaller cells were significantly more frequent in well water samples (p cyanobacteria to wells. Winter samples demonstrated that cyanobacteria accumulate within bank filters, leading to continued passage of cells beyond the bloom season. Although no concentrations of total microcystin-LR were above detection limits in filtered well water, there is concern that cyanobacterial cells that reach the wells have the potential to contain intracellular toxins. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. The filtration properties of a dimorphic yeast

    OpenAIRE

    McCarthy, Anthony A

    2001-01-01

    A dimorphic yeast Kluyveromyces marxianu var. marxianus NRRLy2415 which exhibits a wide range of mean morphological forms was used as a model organism to investigate the role of cell morphology on the dead-end and crossflow filtration behaviour. Varying the culturing conditions produced cell suspensions of different mean morphology. Batch fermentations were used to produce yeast-like morphologies and continuous cultures produced cells more mycelial in nature. Semi-automated image analysis was...

  5. Symptomatic hyponatremia during glomerular filtration rate testing

    OpenAIRE

    2010-01-01

    Hyponatremia affects nearly one in five of all hospitalized patients. Severe hyponatremia is associated with significant morbidity and mortality, and is therefore important to recognize. Prior reports have linked duloxetine with hyponatremia, but it is uncommon. In this case report, we describe a research subject taking duloxetine who developed severe symptomatic hyponatremia during glomerular filtration rate testing despite having undergone such testing uneventfully in the past.

  6. Analysis of Basis Weight Uniformity of Microfiber Nonwovens and Its Impact on Permeability and Filtration Properties

    Science.gov (United States)

    Amirnasr, Elham

    It is widely recognized that nonwoven basis weight non-uniformity affects various properties of nonwovens. However, few studies can be found in this topic. The development of uniformity definition and measurement methods and the study of their impact on various web properties such as filtration properties and air permeability would be beneficial both in industrial applications and in academia. They can be utilized as a quality control tool and would provide insights about nonwoven behaviors that cannot be solely explained by average values. Therefore, for quantifying nonwoven web basis weight uniformity we purse to develop an optical analytical tool. The quadrant method and clustering analysis was utilized in an image analysis scheme to help define "uniformity" and its spatial variation. Implementing the quadrant method in an image analysis system allows the establishment of a uniformity index that can be used to quantify the degree of uniformity. Clustering analysis has also been modified and verified using uniform and random simulated images with known parameters. Number of clusters and cluster properties such as cluster size, member and density was determined. We also utilized this new measurement method to evaluate uniformity of nonwovens produced with different processes and investigated impacts of uniformity on filtration and permeability. The results of quadrant method shows that uniformity index computed from quadrant method demonstrate a good range for non-uniformity of nonwoven webs. Clustering analysis is also been applied on reference nonwoven with known visual uniformity. From clustering analysis results, cluster size is promising to be used as uniformity parameter. It is been shown that non-uniform nonwovens has provide lager cluster size than uniform nonwovens. It was been tried to find a relationship between web properties and uniformity index (as a web characteristic). To achieve this, filtration properties, air permeability, solidity and

  7. Portable Hybrid Powered Water Filtration Device

    Directory of Open Access Journals (Sweden)

    Maria Lourdes V. Balansay

    2015-08-01

    Full Text Available The existing water filtration device has features that can be developed to be more useful and functional during emergency situations. The project’s development has been aided by following provisions in PEC, NEC, NEMA and Philippine National Standard for Safe Drinking Water provide standards for the construction of the project. These standards protect both the prototype and the user. These also served as guide for the maintenance of every component. The design of the portable hybrid powered water filtration device shows that the project has more advanced features such as portability and the power supply used such as photovoltaic module solar cells and manually operated generator. This also shows its effectiveness and reliability based on the results of discharging test, water quality test and water production test. Based on analysis of the overall financial aspects, the machine can be profitable and the amount of revenue and operating cost will increase as years pass. Using the proper machine/ tools and methods of fabrication helps in easy assembly of the project. The materials and components used are cost effective and efficient. The best time for charging the battery using solar panel is 9:00 am onwards while the hand crank generator is too slow because the generated current is little. The water filtration device is very efficient regarding the operating hours and water production. The machine may have a great effect to society and economy in generation of clean available water at less cost.

  8. Closed recirculating system for shrimp-mollusk polyculture

    Science.gov (United States)

    Wu, Xiongfei; Zhao, Zhidong; Li, Deshang; Chang, Kangmei; Tong, Zhuanshang; Si, Liegang; Xu, Kaichong; Ge, Bailin

    2005-12-01

    This paper deals with a new system of aquaculture, i.e., a closed recirculating system for shrimp-mollusk polyculture. The culture system consisted of several shrimp ponds, a mollusk water-purifying pond and a reservoir. During the production cycle, water circulated between the shrimp and mollusk ponds, and the reservoir compensated for water loss from seepage and evaporation. Constricted tagelus, Sinonovacula constricta, was selected as the cultured mollusk, and Pacific white shrimp, Litopenaeus vannamei, as the cultured shrimp. The main managing measures during the production cycle were: setting and using the aerators; introducting the probiotic products timely into the shrimp ponds; adopting a “pen-closing” method for controlling shrimp viral epidemics; setting the flow diversion barriers in the mollusk pond to keep the circulating water flowing through the pond along a sine-like curve and serve as substrate for biofilm; no direct feeding was necessary for the cultured mollusk until the co-cultured shrimp was harvested; natural foods in the water from the shrimp ponds was used for their foods. Two sets of the system were used in the experiment in 2002 and satisfactory results were achieved. The average yield of the shrimp was 11 943.5 kg/hm2, and that of the mollusk was 16 965 kg/hm2. After converting the mollusk yield into shrimp yield at their market price ratio, the food coefficient of the entire system averaged at as low as 0.81. The water quality in the ponds was maintained at a desirable level and no viral epidemics were discovered during the production cycle.

  9. Progress toward a prototype recirculating ion induction accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Friedman, A.; Barnard, J.J.; Cable, M.D. [and others

    1996-06-01

    The U.S. Inertial Fusion Energy (IFE) Program is developing the physics and technology of ion induction accelerators, with the goal of electric power production by means of heavy ion beam-driven inertial fusion (commonly called heavy ion fusion, or HIF). Such accelerators are the principal candidates for inertial fusion power production applications, because they are expected to enjoy high efficiency, inherently high pulse repetition frequency (power plants are expected to inject and burn several fusion targets per second), and high reliability. In addition (and in contrast with laser beams, which are focused with optical lenses) heavy-ion beams will be focused onto the target by magnetic fields, which cannot be damaged by target explosions. Laser beams are used in present-day and planned near-term facilities (such as LLNUs Nova and the National Ignition Facility, which is being designed) because they can focus beams onto very small, intensely illuminated spots for scaled experiments and because the laser technology is already available. An induction accelerator works by passing the beam through a series of accelerating modules, each of which applies an electromotive force to the beam as it goes by; effectively, the beam acts as the secondary winding of a series of efficient one-turn transformers. The authors present plans for and progress toward the development of a small (4.5-m-diam) prototype recirculator, which will accelerate singly charged potassium ions through 15 laps, increasing the ion energy from 80 to 320 keV and the beam current from 2 to 8 mA. Beam confinement and bending are effected with permanent-magnet quadrupoles and electric dipoles, respectively. The design is based on scaling laws and on extensive particle and fluid simulations of the behavior of the space charge-dominated beam.

  10. Closed recirculating system for shrimp-mollusk polyculture

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    This paper deals with a new system of aquaculture, i.e., a closed recirculating system for shrimp-mollusk polyculture. The culture system consisted of several shrimp ponds, a mollusk water-purifying pond and a reservoir. During the production cycle, water circulated between the shrimp and mollusk ponds, and the reservoir compensated for water loss from seepage and evaporation. Constricted tagelus, Sinonovacula constricta, was selected as the cultured mollusk, and Pacific white shrimp, Litopenaeus vannamei, as the cultured shrimp. The main managing measures during the production cycle were: setting and using the aerators; introducing the probiotic products timely into the shrimp ponds; adopting a "pen-closing" method for controlling shrimp viral epidemics; setting the flow diversion barriers in the mollusk pond to keep the circulating water flowing through the pond along a sine-like curve and serve as substrate for biofilm; no direct feeding was necessary for the cultured mollusk until the co-cultured shrimp was harvested; natural foods in the water from the shrimp ponds was used for their foods. Two sets of the system were used in the experiment in 2002 and satisfactory results were achieved. The average yield of the shrimp was 11 943.5 kg/hm2, and that of the mollusk was 16 965kg/hm2. After converting the mollusk yield into shrimp yield at their market price ratio, the food coefficient of the entire system averaged at as low as 0.81. The water quality in the ponds was maintained at a desirable level and no viral epidemics were discovered during the production cycle.

  11. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: BAGHOUSE FILTRATION PRODUCTS, W.L. GORE & ASSOCIATES, INC. LYSB3 FILTER SAMPLE

    Science.gov (United States)

    Baghouse filtration products (BFPs) were evaluated by the Air Pollution Control Technology (APCT) Verification Center. The performance factor verified was the mean outlet particle concentration for the filter fabric as a function of the size for particles equal to or smaller than...

  12. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT, BAGHOUSE FILTRATION PRODUCTS, W.L. GORE & ASSOCIATES, INC., L4427 FILTER SAMPLE

    Science.gov (United States)

    Baghouse filtration products (BFPs) were evaluated by the Air Pollution Control Technology (APCT) Verification Center. The performance factor verified was the mean outlet particle concentration for the filter fabric as a function of the size of those particles equal to and smalle...

  13. Filtration Combustion in Smoldering and SHS

    Science.gov (United States)

    Matkowsky, Bernard J.

    2001-01-01

    Smolder waves and SHS (self-propagating high-temperature synthesis) waves are both examples of filtration combustion waves propagating in porous media. Smoldering combustion is important for the study of fire safety. Smoldering itself can cause damage, its products are toxic and it can also lead to the more dangerous gas phase combustion which corresponds to faster propagation at higher temperatures. In SHS , a porous solid sample, consisting of a finely ground powder mixture of reactants, is ignited at one end. A high temperature thermal wave, having a frontal structure, then propagates through the sample converting reactants to products. The SHS technology appears to enjoy a number of advantages over the conventional technology, in which the sample is placed in a furnace and "baked" until it is "well done". The advantages include shorter synthesis times, greater economy, in that the internal energy of the reactions is employed rather than the costly external energy of the furnace, purer products, simpler equipment and no intrinsic limitation on the size of the sample to be synthesized as exists in the conventional technology. When delivery of reactants through the pores to the reaction site is an important aspect of the combustion process, it is referred to as filtration combustion. The two types of filtration combustion have a similar mathematical formulation, describing the ignition, propagation and extinction of combustion waves in porous media. The goal in each case, however, is different. In smoldering the desired goal is to prevent propagation, whereas in SHS the goal is to ensure propagation of the combustion wave, leading to the synthesis of desired products. In addition, the scales in the two areas of application differ. Smoldering generally occurs at lower temperatures and propagation velocities than in SHS nevertheless, the two applications have much in common so that what is learned fit make application can be used to advantage in the other. In porous

  14. Filtration Efficiency of Functionalized Ceramic Foam Filters for Aluminum Melt Filtration

    Science.gov (United States)

    Voigt, Claudia; Jäckel, Eva; Taina, Fabio; Zienert, Tilo; Salomon, Anton; Wolf, Gotthard; Aneziris, Christos G.; Le Brun, Pierre

    2017-02-01

    The influence of filter surface chemistry on the filtration efficiency of cast aluminum alloys was evaluated for four different filter coating compositions (Al2O3—alumina, MgAl2O4—spinel, 3Al2O3·2SiO2—mullite, and TiO2—rutile). The tests were conducted on a laboratory scale with a filtration pilot plant, which facilitates long-term filtration tests (40 to 76 minutes). This test set-up allows the simultaneous use of two LiMCAs (before and after the filter) for the determination of the efficiency of inclusion removal. The four tested filter surface chemistries exhibited good thermal stability and mechanical robustness after 750 kg of molten aluminum had been cast. All four filter types exhibited a mean filtration efficiency of at least 80 pct. However, differences were also observed. The highest filtration efficiencies were obtained with alumina- and spinel-coated filter surfaces (>90 pct), and the complete removal of the largest inclusions (>90 µm) was observed. The efficiency was slightly lower with mullite- and rutile-coated filter surfaces, in particular for large inclusions. These observations are discussed in relation to the properties of the filters, in particular in terms of, for example, the surface roughness.

  15. Filtration Efficiency of Functionalized Ceramic Foam Filters for Aluminum Melt Filtration

    Science.gov (United States)

    Voigt, Claudia; Jäckel, Eva; Taina, Fabio; Zienert, Tilo; Salomon, Anton; Wolf, Gotthard; Aneziris, Christos G.; Le Brun, Pierre

    2016-12-01

    The influence of filter surface chemistry on the filtration efficiency of cast aluminum alloys was evaluated for four different filter coating compositions (Al2O3—alumina, MgAl2O4—spinel, 3Al2O3·2SiO2—mullite, and TiO2—rutile). The tests were conducted on a laboratory scale with a filtration pilot plant, which facilitates long-term filtration tests (40 to 76 minutes). This test set-up allows the simultaneous use of two LiMCAs (before and after the filter) for the determination of the efficiency of inclusion removal. The four tested filter surface chemistries exhibited good thermal stability and mechanical robustness after 750 kg of molten aluminum had been cast. All four filter types exhibited a mean filtration efficiency of at least 80 pct. However, differences were also observed. The highest filtration efficiencies were obtained with alumina- and spinel-coated filter surfaces (>90 pct), and the complete removal of the largest inclusions (>90 µm) was observed. The efficiency was slightly lower with mullite- and rutile-coated filter surfaces, in particular for large inclusions. These observations are discussed in relation to the properties of the filters, in particular in terms of, for example, the surface roughness.

  16. Mineral and organic compounds in leachate from landfill with concentrate recirculation.

    Science.gov (United States)

    Talalaj, Izabela Anna

    2015-02-01

    The effect of a reverse osmosis concentrate recirculation on the mineral and organic compounds in a landfill leachate was investigated. Investigated was the quality of a leachate from two landfills operated for different periods (a 20-year-old Cell A and a 1-year-old Cell B), where the concentrate was recirculated. Examined were general parameters (conductivity, pH), organic compounds (biochemical oxygen demand (BOD), chemical oxygen demand (COD), total organic nitrogen, BOD/COD), and inorganic compounds (nitrogen ammonia, sulfite, sulfate, cyanide, boron, chloride, ferrous, zinc, chrome, copper). The findings from the first year of investigation showed that over the initial period of recirculation, the concentration of organic compounds (BOD, COD) increased, but after 6 months their values stabilized. It indicates that the concentrate recirculation accelerated organic decomposition, especially in the new landfill Cell. The analysis of inorganic parameters showed that recirculation landfills produce a leachate with a higher concentration of N-NH4, and Cl(-). In case of the old landfill Cell, an increase in B and Fe was also noticeable. These compounds are cyclically washed out from a waste dump and require an additional pretreatment in order to exclude them from recirculation cycle. The increased concentration of Cu, Zn, and Fe was noticed during the initial months of recirculation and in the season of intense atmospheric precipitation in the leachate from both Cells. Higher values of electro conductivity, Cl(-), N-NH4 (+), B, and Fe in the leachate from the old field indicate that the attenuation capacity of this landfill is close to exhaustion.

  17. How can liver toxins be removed? Filtration and adsorption with the Prometheus system.

    Science.gov (United States)

    Vienken, Joerg; Christmann, Horst

    2006-04-01

    The application of extracorporeal blood circuits in liver failure therapy has its roots in the two functions of the liver, first as a detoxifying and second as a synthetizing organ. In contrast to hydrophilic uremic toxins, most liver toxins are hydrophobic and bind preferentially to blood proteins. Consequently, the majority of these compounds cannot be removed by hemodialysis or similar dialytic procedures. Current systems use albumin as a transport vehicle for hydrophobic compounds across high flux membranes (e.g. albumin-dialysis, molecular adsorbent recirculating system (MARS)). In contrast to these devices, the Prometheus system (Fresenius Medical Care, Bad Homburg, Germany) applies filtration across highly permeable membranes with a molecular weight cut-off of >300.000. These membranes facilitate a direct filtration of most of the toxin-bearing proteins. In a secondary circuit these toxins are then removed by adsorber beads assembled in specially designed cartridges. The protein-containing toxin-free solution returns to the primary circuit. Clinical testing of the Prometheus system's safety and efficacy parameters showed that cell counts and coagulation factors were not significantly affected. Total bilirubin-, bile acid- and plasma ammonia-levels were reduced in vivo by -21%, -43% and -40%, respectively. First successful therapeutic results have been obtained for patients treated for drug abuse and for patients waiting for transplantation. Thus, a combination of plasma fractionation with highly permeable membranes followed by a secondary circuit with adsorber cartridges proves to be the most effective method of removing toxic waste in liver failure. Further investigations will follow in order to extend the application of the Prometheus system to larger cohorts of patients.

  18. Modeling of hyperbaric filtration and dewatering of coal

    Science.gov (United States)

    Ranjan, Sushil

    Generalized models have been developed for continuous hyperbaric filtration to evaluate cake formation, filter capacity/filter area, cake dewatering, air consumption and residual cake saturation/residual cake moisture. Emphasis has been placed on cake structure as being a major controlling factor in fine coal dewatering by filtration. The effects of cake structure, as defined by the distributions of pore size and shape, have been reviewed. A simple model relating cake structure to feed particle characteristics is presented and applied to a practical case of fine coal dewatering. A binary packing model has been proposed to explain the existence of compressibility in non-compressible cakes. This model proposes an inner open-structure in the main cake, with the inner layer being compressible. The variation in the inner cake porosity with applied pressure has been used to explain the change in specific cake resistance and filter capacity (solids cake throughput). Process simulations have been conducted for a single stage and a two stage process, wherein the original feed has been split into a coarse fraction and a fine fraction (and then each fraction processed separately). The process simulations for a two stage process show a lot of promise as this leads to a lowering of the required filter area and the residual cake moisture. The required filter area increases, while the residual cake moisture decreases as the cut size for the two stage process is increased. However, the advantages of a two stage process are adversely affected by an inefficient separation process, which leads to an increased filter area and a higher residual cake moisture and the two stage process approaches a single stage process.

  19. Enhancing treatment efficiency of swine wastewater by effluent recirculation in vertical-flow constructed wetland

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Livestock wastewater has been a major contributor to Chinese cultural eutrophication of surface waters. Constructed wetlands are under study as a best management practice to treat wastewater from dairy and swine operations, but the removal efficiency of pollutants is relatively low. Enhancing the treatment efficiency of livestock wastewater by effluent recirculation was investigated in a pilot-scale vertical-flow constructed wetland. The wetland system was composed of downflow and upflow stages, on which narrow-leafPhragmites communis and common reed Phragmites Typhia are planted, respectively; each stage has a dimension of4 m2 (2 m × 2 m). Wastewater from facultative pond was fed into the system intermittently at a flow rate of 0.4 m3/d. Recirculation rates of 0, 25%, 50%, 100% and 150% were adopted to evaluate the effect of the recirculation rate on pollutants removal. It shows that with effluent recirculation the average removal efficiencies of NH4-N, biological oxygen demand (BOD5) and suspended solids(SS)obviously increase to 61.7%, 81.3%, and 77.1%, respectively, in comparison with the values of 35.6%, 50.2%, and 49.3% without effluent recirculation. But the improvement of TP removal is slight, only from 42.3% to 48.9%. The variations of NH4-N, dissolved oxygen(DO) and oxidation-reduction potential(ORP) of inflow and outflow reveal that the adoption of effluent recirculation is beneficial to the formation of oxide environment in wetland. The exponential relationships with excellent correlation coefficients (R2 >0.93)are found between the removal rates of NH4-N and BOD5 and the recirculation rates. With recirculation the pH value of the outflow decreases as the alkalinity is consumed by gradually enhanced nitrification process. When recirculation rate is kept constant 100%, the ambient temperature appears to affect NH4-N removal, but does not have significant influence on BOD5 removal.

  20. Noscapine recirculates enterohepatically and induces self-clearance.

    Science.gov (United States)

    Mukkavilli, Rao; Gundala, Sushma R; Yang, Chunhua; Jadhav, Gajanan R; Vangala, Subrahmanyam; Reid, Michelle D; Aneja, Ritu

    2015-09-18

    Noscapine (Nos), an antitussive benzylisoquinoline opium alkaloid, is a non-toxic tubulin-binding agent currently in Phase II clinical trials for cancer chemotherapy. While preclinical studies have established its tumor-inhibitory properties in various cancers, poor absorptivity and rapid first-pass metabolism producing several uncharacterized metabolites for efficacy, present an impediment in translating its efficacy in humans. Here we report novel formulations of Nos in combination with dietary agents like capsaicin (Cap), piperine (Pip), eugenol (Eu) and curcumin (Cur) known for modulating Phase I and II drug metabolizing enzymes. In vivo pharmacokinetic (PK), organ toxicity evaluation of combinations, microsomal stability and in vitro cytochrome P450 (CYP) inhibition effects of Nos, Cap and Pip using human liver microsomes were performed. Single-dose PK screening of combinations revealed that the relative exposure of Nos (2 μg h/mL) was enhanced by 2-fold (4 μg h/mL) by Cap and Pip and their plasma concentration-time profiles showed multiple peaking phenomena for Nos indicating enterohepatic recirculation or differential absorption from intestine. CYP inhibition studies confirmed that Nos, Cap and Pip are not potent CYP inhibitors (IC50>1 μM). Repeated oral dosing of Nos, Nos+Cap and Nos+Pip showed lower exposure (Cmax and AUClast) of Nos on day 7 compared to day 1. Nos Cmax decreased from 3087 ng/mL to 684 ng/mL and AUClast from 1024 ng h/mL to 508 ng h/mL. In presence of Cap and Pip, the decrease in Cmax and AUClast of Nos was similar. This may be due to potential enzyme induction leading to rapid clearance of Nos as the trend was observed in Nos alone group also. The lack of effect on intrinsic clearance of Nos suggests that the potential drug biotransformation modulators employed in this study did not contribute toward increased exposure of Nos on repeated dosing. We envision that Nos-induced enzyme induction could alter the therapeutic efficacy of co

  1. Transfer and transport of aluminum in filtration unit

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Aluminum salt coagulants were used prevalently in various water works. In this article, the effects of filtration on residual aluminum concentration and species distribution were researched by determining the concentration of different Aluminum species before and after single layer filter, double layer filter, and membrane filtration units. In the research, size exclusion chromatography (SEC) was used to separate colloidal and soluble aluminum, ion exchange chromatography (IEC) was used to separate organic and inorganic aluminum, and inductivity coupled plasma-atomic emission spectrometry (ICP-AES) was used to determine the aluminum concentration. The results showed that the rapid filtration process had the ability of removing residual aluminum from coagulant effluent water, and that double layer filtration was more effective in residual aluminum removal than single layer filtration, while Nano filtration was more effective than micro filtration. It was found that when the residual aluminum concentration was below 1mg/L in sediment effluent, the residual aluminum concentration in treated water was above 0.2 mg/L. The direct rapid filtration process mainly removed the suspended aluminum. The removal of soluble and colloidal aluminum was always less than 10% and the natural small particles that adsorbed the amount of soluble or small particles aluminum on their surface were difficult to be removed in this process. Micro filtration and nano filtration were good technologies for removing aluminum; the residual aluminum concentration in the effluent was less than 0.05 mg/L.

  2. Martingale representation property in progressively enlarged filtrations

    CERN Document Server

    Jeanblanc, M

    2012-01-01

    Consider $\\mathbb{G}$ the progressive enlargement of a filtration $\\mathbb{F}$ with a random time $\\tau$. Assuming that, in $\\mathbb{F}$, the martingale representation property holds, we examine conditions under which the martingale representation property holds also in $\\mathbb{G}$. It is noted that the classical results on this subject are no more sufficient to deal with all examples coming from credit risk modeling. In this paper, we introduce a new methodology which extends the various classical results and applies on recent examples.

  3. Concentrations of selected contaminants in cabin air of airbus aircrafts.

    Science.gov (United States)

    Dechow, M; Sohn, H; Steinhanses, J

    1997-07-01

    The concentrations of selected air quality parameters in aircraft cabins were investigated including particle numbers in cabin air compared to fresh air and recirculation air, the microbiological contamination and the concentration of volatile organic compounds (VOC). The Airbus types A310 of Swissair and A340 of Lufthansa were used for measurements. The particles were found to be mainly emitted by the passengers, especially by smokers. Depending on recirculation filter efficiency the recirculation air contained a lower or equal amount of particles compared to the fresh air, whereas the amount of bacteria exceeded reported concentrations within other indoor spaces. The detected species were mainly non-pathogenic, with droplet infection over short distances identified as the only health risk. The concentration of volatile organic compounds (VOC) were well below threshold values. Ethanol was identified as the compound with the highest amount in cabin air. Further organics were emitted by the passengers--as metabolic products or by smoking--and on ground as engine exhaust (bad airport air quality). Cleaning agents may be the source of further compounds.

  4. Effects of Exhaust Gas Recirculation on the Homogeneous Charge Combustion Process of n-Heptane at Different Load Conditions

    Institute of Scientific and Technical Information of China (English)

    LIU Dexin; FENG Hongqing; ZHENG Jincai; MILLER David L; CERNANSKY Nicholas P

    2005-01-01

    Effects of exhaust gas recirculation (EGR) on homogeneous charge combustion of n-heptane was studied through simulation and experiment. Experiments were carried out in a single cylinder, four-stroke, air cooled engine and a single cylinder, two-stroke, water cooled engine. In the four-stroke engine, experiments of the effects of EGR were examined using heated N2 addition as a surrogate for external EGR and modifying engine to increase internal EGR. The ignition timing was sensitive to EGR due to thermal and chemical effects. EGR or extra air is a key factor in eliminating knock during mid-load conditions. For higher load operation the only way to avoid knock is to control reaction timing through the use of spark ignition. Experimental and modeling results from the two-stroke engine show that auto-ignition can be avoided by increasing the engine speed. The two-stroke engine experiments indicate that high levels of internal EGR can enable spark ignition at lean conditions. At higher load conditions, increasing the engine speed is an effective method to control transition from homogeneous charge compression ignition (HCCI) operation to non-HCCI operation and successful spark ignition of a highly dilute mixture can avoid serious knock.

  5. Next Generation Pressurized Oxy-Coal Combustion: High Efficiency and No Flue Gas Recirculation

    Energy Technology Data Exchange (ETDEWEB)

    Rue, David

    2013-09-30

    The Gas Technology Institute (GTI) has developed a pressurized oxy-coal fired molten bed boiler (MBB) concept, in which coal and oxygen are fired directly into a bed of molten coal slag through burners located on the bottom of the boiler and fired upward. Circulation of heat by the molten slag eliminates the need for a flue gas recirculation loop and provides excellent heat transfer to steam tubes in the boiler walls. Advantages of the MBB technology over other boilers include higher efficiency (from eliminating flue gas recirculation), a smaller and less expensive boiler, modular design leading to direct scalability, decreased fines carryover and handling costs, smaller exhaust duct size, and smaller emissions control equipment sizes. The objective of this project was to conduct techno-economic analyses and an engineering design of the MBB project and to support this work with thermodynamic analyses and oxy-coal burner testing. Techno-economic analyses of GTI’s pressurized oxy-coal fired MBB technology found that the overall plant with compressed CO2 has an efficiency of 31.6%. This is a significant increase over calculated 29.2% efficiency of first generation oxy-coal plants. Cost of electricity (COE) for the pressurized MBB supercritical steam power plant with CO2 capture and compression was calculated to be 134% of the COE for an air-coal supercritical steam power plant with no CO2 capture. This compares positively with a calculated COE for first generation oxy-coal supercritical steam power plants with CO2 capture and compression of 164%. The COE for the MBB power plant is found to meet the U.S. Department of Energy (DOE) target of 135%, before any plant optimization. The MBB power plant was also determined to be simpler than other oxy-coal power plants with a 17% lower capital cost. No other known combustion technology can produce higher efficiencies or lower COE when CO2 capture and compression are included. A thermodynamic enthalpy and exergy analysis

  6. Method and apparatus for control of coherent synchrotron radiation effects during recirculation with bunch compression

    Energy Technology Data Exchange (ETDEWEB)

    Douglas, David R; Tennant, Christopher

    2015-11-10

    A modulated-bending recirculating system that avoids CSR-driven breakdown in emittance compensation by redistributing the bending along the beamline. The modulated-bending recirculating system includes a) larger angles of bending in initial FODO cells, thereby enhancing the impact of CSR early on in the beam line while the bunch is long, and 2) a decreased bending angle in the final FODO cells, reducing the effect of CSR while the bunch is short. The invention describes a method for controlling the effects of CSR during recirculation and bunch compression including a) correcting chromatic aberrations, b) correcting lattice and CSR-induced curvature in the longitudinal phase space by compensating T.sub.566, and c) using lattice perturbations to compensate obvious linear correlations x-dp/p and x'-dp/p.

  7. DISPERSION COMPENSATION CFBG IN 100km 10Gbit/s RECIRCULATING SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    Yang Aiying; Wang Ziyu; Zhang Zhaoyi; Chen Zhangyuan; Wu Deming

    2003-01-01

    A 10 Gbit/s recirculating system is configured with Chirped Fiber Bragg Grating (CFBG) for the dispersion compensation. For the first time, the transmission distance in the loop reaches 1000km with bit error rate of 10-9. The effect of the group delay ripple of the fiber grating is also investigated in the recirculating systems, and it is shown that the transmission distance is limited to 4 cycles (4× 167.1km ) in the loop with the power penalty fluctuation below 1.0dB. Thus the group delay ripple should be reduced to allow for the wavelength drift of ±5GHz.At the end of this letter, the principles are given for designing long haul recirculating systems with dispersion compensation CFBG.

  8. Controlled reattachment in separated flows: a variational approach to recirculation length reduction

    CERN Document Server

    Boujo, E

    2014-01-01

    A variational technique is used to derive analytical expressions for the sensitivity of recirculation length to steady forcing in separated flows. Linear sensitivity analysis is applied to the two-dimensional steady flow past a circular cylinder for Reynolds numbers $40 \\leq Re \\leq 120$, both in the subcritical and supercritical regimes. Regions which are the most sensitive to volume forcing and wall blowing/suction are identified. Control configurations which reduce the recirculation length are designed based on the sensitivity information, in particular small cylinders used as control devices in the wake of the main cylinder, and fluid suction at the cylinder wall. Validation against full non-linear Navier-Stokes calculations shows excellent agreement for small-amplitude control. The linear stability properties of the controlled flow are systematically investigated. At moderate Reynolds numbers, we observe that regions where control reduces the recirculation length correspond to regions where it has a stab...

  9. Thermodynamic Model for Updraft Gasifier with External Recirculation of Pyrolysis Gas

    Directory of Open Access Journals (Sweden)

    Fajri Vidian

    2016-01-01

    Full Text Available Most of the thermodynamic modeling of gasification for updraft gasifier uses one process of decomposition (decomposition of fuel. In the present study, a thermodynamic model which uses two processes of decomposition (decomposition of fuel and char is used. The model is implemented in modification of updraft gasifier with external recirculation of pyrolysis gas to the combustion zone and the gas flowing out from the side stream (reduction zone in the updraft gasifier. The goal of the model obtains the influences of amount of recirculation pyrolysis gas fraction to combustion zone on combustible gas and tar. The significant results of modification updraft are that the increases amount of recirculation of pyrolysis gas will increase the composition of H2 and reduce the composition of tar; then the composition of CO and CH4 is dependent on equivalence ratio. The results of the model for combustible gas composition are compared with previous study.

  10. Recurrent amoebic gill infestation in rainbow trout cultured in a semiclosed water recirculation system

    Science.gov (United States)

    Noble, A.C.; Herman, R.L.; Noga, E.J.; Bullock, G.L.

    1997-01-01

    Five lots of commercially purchased juvenile rainbow trout Oncorhynchus mykiss (17-44 g) stocked in a continuous-production water recirculation system became infested with gilt amoebae. The amoebae were introduced into the recirculation system, as evidenced by their presence on gills of fish held in quarantine tanks. Based on their morphology, as seen in histological sections and by electron microscopy, the amoebae appeared to be more closely related to the family Cochliopodiidae than to other taxa of free living amoebae. Attempts to culture the amoebae in different media, at different temperatures of incubation, and in fish cell culture were not successful. Initial treatment of the recirculation system with formalin at 167 parts per million (ppm) for 1 h eliminated amoebae from the gills. Subsequent treatments of the entire system with formalin at 50-167 ppm reduced the intensity of further infestations.

  11. Saponification pretreatment and solids recirculation as a new anaerobic process for the treatment of slaughterhouse waste.

    Science.gov (United States)

    Affes, R; Palatsi, J; Flotats, X; Carrère, H; Steyer, J P; Battimelli, A

    2013-03-01

    Different configurations of anaerobic process, adapted to the treatment of solid slaughterhouse fatty waste, were proposed and evaluated in this study. The tested configurations are based on the combination of anaerobic digestion with/without waste saponification pretreatment (70 °C during 60 min) and with/without recirculation of the digestate solid fraction (ratio=20% w/w). After an acclimation period of substrate pulses-feeding cycles, the reactors were operated in a semi-continuous feeding mode, increasing organic loading rates along experimental time. The degradation of the raw substrate was shown to be the bottleneck of the whole process, obtaining the best performance and process yields in the reactor equipped with waste pretreatment and solids recirculation. Saponification promoted the emulsification and bioavailability of solid fatty residues, while recirculation of solids minimized the substrate/biomass wash-out and induced microbial adaptation to the treatment of fatty substrates.

  12. Control oriented modeling of ejector in anode gas recirculation solid oxygen fuel cell systems

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Yinhai, E-mail: yinhai.zhu@gmail.co [School of Energy and Power Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Li Yanzhong, E-mail: yzli-epe@mail.xjtu.edu.c [School of Energy and Power Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Cai Wenjian [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

    2011-04-15

    A one-equation model is proposed for fuel ejector in anode gas recirculation solid oxide fuel cell (SOFC) system. Firstly, the fundamental governing equations are established by employing the thermodynamic, fluid dynamic principles and chemical constraints inside the ejector; secondly, the one-equation model is derived by using the parameter analysis and lumped-parameter method. Finally, the computational fluid dynamics (CFD) technique is employed to obtain the source data for determining the model parameters. The effectiveness of the model is studied under a wide range of operation conditions. The effect of ejector performance on the anode gas recirculation SOFC system is also discussed. The presented model, which only contains four constant parameters, is useful in real-time control and optimization of fuel ejector in the anode gas recirculation SOFC system.

  13. Investigation of hydrocarbon oil transformation by gliding arc discharge: comparison of batch and recirculated configurations

    Science.gov (United States)

    Whitehead, J. Christopher; Prantsidou, Maria

    2016-04-01

    The degradation of liquid dodecane was studied in a gliding arc discharge (GAD) of humid argon or nitrogen. A batch or recirculating configuration was used. The products in the gaseous and liquid phase were analysed by infrared and chromatography and optical emission spectroscopy was used to identify the excited species in the discharge. The best degradation performance comes from the use of humid N2 but a GAD of humid argon produces fewer gas-phase products but more liquid-phase end-products. A wide range of products such as heavier saturated or unsaturated hydrocarbons both aliphatic and aromatic, and oxidation products mainly alcohols, but also aldehydes, ketones and esters are produced in the liquid-phase. The recirculating treatment mode is more effective than the batch mode increasing the reactivity and changing the product selectivities. Overall, the study shows promising results for the organic liquid waste treatment, especially in the recirculating mode.

  14. Low-cost multi-stage filtration enhanced by coagulation-flocculation in upflow gravel filtration

    NARCIS (Netherlands)

    Sanchez, L.D.; Marin, L.M.; Visscher, J.T.; Rietveld, L.C.

    2012-01-01

    This paper assesses the operational and design aspects of coagulation and flocculation in upflow gravel filters (CF-UGF) in a multi-stage filtration (MSF) plant. This study shows that CF-UGF units improve the performance of MSF considerably, when the system operates with turbidity above 30 NTU. It s

  15. Dynamic optimization of a dead-end filtration trajectory : Non-ideal cake filtration

    NARCIS (Netherlands)

    Blankert, Bastiaan; Kattenbelt, Carolien; Betlem, Ben H.L.; Roffel, Brian

    2007-01-01

    A control strategy aimed at minimizing energy consumption is formulated for non-ideal dead-end cake filtration with an inside-out hollow fiber ultrafiltration membrane system. The non-ideal behavior was assumed to originate from cake compression, non-linear cake resistance and a variable pump effici

  16. Dynamic optimization of a dead-end filtration trajectory : Blocking filtration laws

    NARCIS (Netherlands)

    Blankert, Bastiaan; Betlem, Ben H.L.; Roffel, Brian

    2006-01-01

    An operating model for dead-end membrane filtration is proposed based on the well-known blocking laws. The resulting model contains three parameters representing, the operating strategy, the fouling mechanism and the fouling potential of the feed. The optimal control strategy is determined by minimi

  17. Selective NOx Recirculation for Stationary Lean-Burn Natural Gas Engines

    Energy Technology Data Exchange (ETDEWEB)

    Nigel Clark; Gregory Thompson; Richard Atkinson; Richard Turton; Chamila Tissera; Emre Tatli; Andy Zimmerman

    2005-12-28

    Selective NOx Recirculation (SNR) involves cooling the engine exhaust gas and then adsorbing the oxides of nitrogen (NOx) from the exhaust stream, followed by the periodic desorption of NOx. By returning the desorbed, concentrated NOx into the engine intake and through the combustion chamber, a percentage of the NOx is decomposed during the combustion process. An initial study of NOx decomposition during lean-burn combustion was concluded in 2004 using a 1993 Cummins L10G 240hp natural gas engine. It was observed that the air/fuel ratio, injected NO (nitric oxide) quantity and engine operating points affected NOx decomposition rates of the engine. Chemical kinetic modeling results were also used to determine optimum NOx decomposition operating points and were published in the 2004 annual report. A NOx decomposition rate of 27% was measured from this engine under lean-burn conditions while the software model predicted between 35-42% NOx decomposition for similar conditions. A later technology 1998 Cummins L10G 280hp natural gas engine was procured with the assistance of Cummins Inc. to replace the previous engine used for 2005 experimental research. The new engine was equipped with an electronic fuel management system with closed-loop control that provided a more stable air/fuel ratio control and improved the repeatability of the tests. The engine was instrumented with an in-cylinder pressure measurement system and electronic controls, and was adapted to operate over a range of air/fuel ratios. The engine was connected to a newly commissioned 300hp alternating current (AC) motoring dynamometer. The second experimental campaign was performed to acquire both stoichiometric and slightly rich (0.97 lambda ratio) burn NOx decomposition rates. Effects of engine load and speed on decomposition were quantified, but Exhaust Gas Recirculation (EGR) was not varied independently. Decomposition rates of up to 92% were demonstrated. Following recommendations at the 2004 ARES peer

  18. METC CFD simulations of hot gas filtration

    Energy Technology Data Exchange (ETDEWEB)

    O`Brien, T.J.

    1995-06-01

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

  19. Diatomite releases silica during spirit filtration.

    Science.gov (United States)

    Gómez, J; Gil, M L A; de la Rosa-Fox, N; Alguacil, M

    2014-09-15

    The purpose of this study was to ascertain whether diatomite is an inert filter aid during spirit filtration. Surely, any compound with a negative effect on the spirit composition or the consumer's health could be dissolved. In this study different diatomites were treated with 36% vol. ethanol/water mixtures and the amounts and structures of the extracted compounds were determined. Furthermore, Brandy de Jerez was diatomite- and membrane-filtered at different temperatures and the silicon content was analysed. It was found that up to 0.36% by weight of diatomite dissolved in the aqueous ethanol and amorphous silica, in the form of hollow spherical microparticles, was the most abundant component. Silicon concentrations in Brandy de Jerez increased by up to 163.0% after contact with diatomite and these changes were more marked for calcined diatomite. In contrast, reductions of more than 30% in silicon concentrations were achieved after membrane filtration at low temperatures. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Renal filtration function in patients with gout

    Directory of Open Access Journals (Sweden)

    N. N. Kushnarenko

    2016-01-01

    Full Text Available Aim. To study circadian blood pressure (BP profile in patients with gout depending on the presence of arterial hypertension (HT and their relationship to the renal filtration function.Material and methods. Patients with gout (n=87 were included into the study. All the patients underwent ambulatory BP monitoring (ABPM with the assessment of circadian BP profile, determination of uric acid serum levels, glomerular filtration rate (GFR was evaluated by CKD-EPI method. Depending on GFR level, all the patients were divided into 2 groups - with renal dysfunction or without one.Results. ABPM revealed circadian BP dysregulation in 55% of gout patients both with HT and without HT. Chronic kidney disease (CKD was revealed in 72.4% of male patients, with the prevalence in patients with HT (76.6 vs 61%; p<0.001. Correlations between uric acid levels and some ABPM indicators and GFR were determined.Conclusion. Obtained data suggest the contribution of hyperuricemia in disorders of systemic and renal hemodynamics, leading to the early development of CKD.

  1. Riverbed Clogging and Sustainability of Riverbank Filtration

    Directory of Open Access Journals (Sweden)

    Thomas Grischek

    2016-12-01

    Full Text Available Clogging refers to a reduction of riverbed hydraulic conductivity. Due to difficulties in determining the thickness of the clogging layer, the leakage coefficient (L is introduced and used to quantify the recoverable portion of bank filtrate. L was determined at several riverbank filtration (RBF sites in field tests and using an analytical solution. Results were compared with data from similar experiments in the early 1970s and 1991–1993. In the 1980s, severe river water pollution in conjunction with high water abstraction led to partly unsaturated conditions beneath the riverbed. A leakage coefficient L of 5 × 10−7 s−1 was determined. After water quality improvement, L increased to 1–1.5 × 10−6 s−1. An alternative, cost and time efficient method is presented to estimate accurate leakage coefficients. The analytical solution is based on groundwater level monitoring data from observation wells next to the river, which can later feed into numerical models. The analytical approach was able to reflect long-term changes as well as seasonal variations. Recommendations for its application are given based on experience.

  2. Contribution of seawater recirculation to submarine groundwater discharge and related nutrient fluxes in two tropical bays

    Science.gov (United States)

    Vautier, Camille; Dulaiova, Henrietta

    2017-04-01

    Hawaiian coastal waters suffer from excess terrestrial nutrient loading, most of which comes from submarine groundwater discharge (SGD). This study quantifies and distinguishes the role of the fresh terrestrial and tidally pumped salt water components of SGD into the nearshore zone of two reefs on the island of Oahu: Maunalua Bay and Kāneohe Bay. The two components of SGD are characterized using isotopic techniques, and the study mainly focuses on the less understood recirculation component. A two-step approach is implemented: first, a conceptual model of groundwater circulation is established; second, nutrient fluxes associated with seawater recirculation are quantified. Groundwater circulation through the beach berm is quantified and characterized using 222Rn and 224Ra activity measurements. Nutrient fluxes are obtained by coupling nutrient concentration measurements and discharge estimates. The isotopic signatures inform us about the influence of the tidal cycle on groundwater circulation. 222Rn, 224Ra, and δ18O isotopes are used to derive apparent ages of the infiltrated seawater and allow us to quantify recirculation rates. The method is also complemented with the use of silicate concentration as tracers of the recirculation process. The trends in apparent ages observed in pore water in Maunalua match previously published conceptual groundwater circulation models and show a sequentially aging pore water circulation loop. However, the ages obtained in Kāneohe suggest a different tidal pumping dynamic that lacks a circulation loop, perhaps resulting from the absence of freshwater discharge. Derived nutrient fluxes show that the autochthonous production of inorganic nitrogen and phosphorus that occurs during seawater recirculation has a significant impact on nutrient cycles in the nearshore areas of the bays. This result suggests that seawater recirculation should be taken into account in biogeochemical studies of coastal areas.

  3. The Two Branches of the Recirculation of Atlantic Water in Fram Strait

    Science.gov (United States)

    von Appen, Wilken-Jon; Schauer, Ursula; Hattermann, Tore; Albretsen, Jon

    2016-04-01

    The Fram Strait between Greenland and Svalbard is one of the two gateways by which warm Atlantic Water enters the Arctic Ocean providing oceanic heat. The West Spitsbergen Current advects the warm water northward in the eastern Fram Strait. However, only some of this water stays in the boundary current and enters the Arctic Ocean. Another part leaves the boundary current and flows westward across Fram Strait before turning southward in the East Greenland Current. This recirculation of Atlantic Water corresponds with the ice edge in Fram Strait and the two likely depend on each other. Here we present results from a high resolution regional numerical model that shows the recirculation to consist of two branches. The northern branch depends on eddy fluxes while the southern branch exhibits less high frequency variability. We also present a compilation of different observational data in the center of Fram Strait around 0°EW that give insight into the structure of the southern recirculation branch near the ice edge. A glider section resolves the small horizontal scale over which the geostrophic flow occurs. Several meridional CTD sections capture the differences and similarities between different summers. Moorings and Argo floats provide information in winter as well. These observations are compared to the representation of the recirculation in the numerical model. We show that the southern recirculation occurs over a small horizontal distance of about 20km in the vicinity of 79°N and is significantly stronger in winter than in summer. While there is cold freshwater at the surface north of the front, the temperature down to 500m is much higher in the recirculation than further south.

  4. A study of dynamic filtration; Um estudo sobre filtracao dinamica

    Energy Technology Data Exchange (ETDEWEB)

    Girao, Joaquim Helder S. [PETROBRAS, Natal, RN (Brazil). Distrito de Perfuracao da Bacia Potiguar. Div. de Tecnicas de Perfuracao

    1989-12-31

    The problems that cause cost increase such as: formation damage and borehole swelling or caving lead us to study the filtration of the liquid part of formation drilling fluid. With the aim of comparing static and dynamic filtration rates, we developed a modest dynamic filtration equipment, consisting of a modified API filter, connected to reservoir by means of a positive injection pump. We carried out various tests, and the results were set in charts and tables. Through these, it is possible to notice how the static and dynamic filtration curves come apart for a same pressure value. We also evaluated the effects of circulation speed, starch concentration and counter pressure. This paper does not include calculations or mathematical models accounting for filtrate invasion radii, but it demonstrates, for example, that cleaning circulation will cause lower filtration rates at lower flows. (author) 5 refs., 11 figs., 14 tabs.

  5. Physicochemical interaction and its influence on deep bed filtration process.

    Science.gov (United States)

    Guo, Jin-long; Meng, Jun; Li, Gui-ping; Luan, Zhao-kun; Tang, Hong-xiao

    2004-01-01

    The capillary model was used to analyze the hydraulic conditions in the deep bed filtration process. The physicochemical interaction forces between the filter media and suspended particles and their influence on deep bed filtration process were also studied theoretically. Through the comparison of the hydraulic and physicochemical forces, the key influencing factors on the filtration process were proposed and investigated. Pilot study of the microflocculation deep bed filtration was carried out in the No. 9 Potable Water Treatment Plant of Beijing, and the experimental results of hydraulic head loss, particle distribution and entrapment were presented. The theoretical prediction was reasonably consistent with the experimental results under different conditions, which indicated that the regulation and control of micro-flocculation and deep bed filtration could be realized by the evaluation of the physicochemical interactions. Further theoretical and experimental research should be carried out to investigate the interaction mechanism and its application in the deep bed filtration and other cases.

  6. In-Water Hull Cleaning & Filtration System

    Science.gov (United States)

    George, Dan

    2015-04-01

    Dan George R & D Mining Technology LinkedIn GRD Franmarine have received the following prestigious awards in 2014 for their research & development of an in-water hull cleaning and filtration system "The Envirocart: Golden Gecko Award for Environmental Excellence; WA Innovator of the Year - Growth Sector; Department of Fisheries - Excellence in Marine Biosecurity Award - Innovation Category; Lloyd's List Asia Awards - Environmental Award; The Australian Innovation Challenge - Environment, Agriculture and Food Category; and Australian Shipping and Maritime Industry Award - Environmental Transport Award. The Envirocart developed and patented by GRD Franmarine is a revolutionary new fully enclosed capture and containment in-water hull cleaning technology. The Envirocart enables soft Silicon based antifouling paints and coatings containing pesticides such as Copper Oxide to be cleaned in situ using a contactless cleaning method. This fully containerised system is now capable of being deployed to remote locations or directly onto a Dive Support Vessel and is rated to offshore specifications. This is the only known method of in-water hull cleaning that complies with the Department of Agriculture Fisheries and Forestry (DAFF) and Department of Fisheries WA (DoF) Guidelines. The primary underwater cleaning tool is a hydraulically powered hull cleaning unit fitted with rotating discs. The discs can be fitted with conventional brushes for glass or epoxy based coatings or a revolutionary new patented blade system which can remove marine biofouling without damaging the antifouling paint (silicone and copper oxide). Additionally there are a patented range of fully enclosed hand cleaning tools for difficult to access niche areas such as anodes and sea chests, providing an innovative total solution that enables in-water cleaning to be conducted in a manner that causes no biological risk to the environment. In full containment mode or when AIS are present, material is pumped

  7. Performance of the prototype gas recirculation system with built-in RGA for INO RPC system

    Energy Technology Data Exchange (ETDEWEB)

    Bhuyan, M. [Department of High Energy Physics, Tata Institute of Fundamental Research, Mumbai 400005 (India); Datar, V.M. [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Joshi, A. [Alpha Pneumatics, 11-Krishna Kutir, Madanlal Dhingra Road, Thane 400602 (India); Kalmani, S.D., E-mail: kalmani@tifr.res.in [Department of High Energy Physics, Tata Institute of Fundamental Research, Mumbai 400005 (India); Mondal, N.K. [Department of High Energy Physics, Tata Institute of Fundamental Research, Mumbai 400005 (India); Rahman, M.A. [Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Mumbai 400005 (India); Satyanarayana, B.; Verma, P. [Department of High Energy Physics, Tata Institute of Fundamental Research, Mumbai 400005 (India)

    2012-01-01

    An open loop gas recovery and recirculation system has been developed for the INO RPC system. The gas mixture coming from RPC exhaust is first desiccated by passing through molecular sieve (3 Angstrom-Sign +4 Angstrom-Sign ). Subsequent scrubbing over basic active alumina removes toxic and acidic contaminants. The Isobutane and Freon are then separated by diffusion and liquefied by fractional condensation by cooling up to -26{sup Ring-Operator }C. A Residual Gas Analyser (RGA) is being used in the loop to study the performance of the recirculation system. The results of the RGA analysis will be discussed.

  8. Cleaning and recirculation of perfluorohexane ($C_{6} F_{14}$) in the STAR-RICH detector

    CERN Document Server

    Andrés, Yu; Cozza, D; Davenport, M; De Cataldo, G; Dell'Olio, L; Di Bari, D; Di Mauro, A; Dunlop, J C; Finch, E; Fraissard, Daniel; Franco, A; Gans, J; Ghidini, B; Harris, J W; Horsley, M; Kunde, G J; Lasiuk, B; Lesenechal, Y; Majka, R D; Martinengo, P; Morsch, Andreas; Nappi, E; Paic, G; Piuz, François; Posa, F; Raynaud, J; Salur, S; Sandweiss, J; Santiard, Jean-Claude; Satinover, J; Schyns, E M; Smirnov, N; Van Beelen, J; Williams, T D; Xu, Z

    2002-01-01

    A RICH detector with a CsI photo-cathode and liquid perfluorohexane radiator has been installed in the STAR experiment at RHIC. The liquid is continuously cleaned and distributed to a quartz containment vessel within the detector by a closed recirculation system. A VUV spectrometer is connected to the system which monitors the optical transparency of the liquid. This measurement provides one of the pieces of information necessary to model the number of Cherenkov photons which reach the pad plane. A description of the liquid recirculation system and the cleaning procedure for the liquid as well as the spectrometer is presented along with results of their performance. (23 refs).

  9. NUTRIENTS DYNIMIC IN AN AQUAPONIC RECIRCULATING SYSTEM FOR STURGEON AND LETTUCE (LACTUCA SATIVA PRODUCTION

    Directory of Open Access Journals (Sweden)

    LORENA SFETCU

    2013-12-01

    Full Text Available Aquaponics are modern production systems, which integrate the aquaculture technology with hydroponic systems (vegetable production without soil with a goal of fructification of residual nutrients resulted from metabolic activity of fish biomass as high quality vegetable biomass sealable as ecological products. In the present study, as a first step in aquaponic recirculating systems evaluation, the authors aim to compare two types of recirculating systems: classical (hereby noted with RAS and integrated/aquaponic (RAS_A regarding water quality parameters generally, and TAN (total ammonia nitrogen production and transformation, particularly.

  10. The effect of filter cake viscoelasticity on filtration

    DEFF Research Database (Denmark)

    Christensen, Morten Lykkegaard

    Wastewater is usually treated biologically, and a by-product from this treatment is waste-activated sludge with high water content. Sludge is therefore often filtrated to reduce the volume for handling and disposal, and to minimise the water content before incineration of the sludge. However...... a function of pressure as assumed when using the conventional models. Moreover, it is shown how the existing filtration models can be modified and the filtration process for activated sludge simulated....

  11. Analysis of fouling development under dynamic membrane filtration operation

    OpenAIRE

    Saleem, Mubashir; Alibardi, Luca; Cossu, Raffaello; Lavagnolo, Maria Cristina; Spagni, Alessandro

    2016-01-01

    This research is a contribution towards evaluating the appropriate fouling mechanism responsible for the flux decline under dynamic membrane (DM) filtration and its formation mechanism by using gravity-driven filtration in a specifically designed experimental setup. Series of extended short term filtration experiments were performed at varying operating conditions of mixed liquor suspended solids (MLSS) concentrations, trans-membrane pressures (TMP) and mesh pore sizes. Blocking models were a...

  12. Removal of cytomegalovirus DNA from donor blood by filtration.

    Science.gov (United States)

    Smith, K L; Cobain, T; Dunstan, R A

    1993-04-01

    Blood from five donors, previously shown to be positive for cytomegalovirus (CMV) DNA following polymerase chain reaction (PCR) amplification, was filtered through commercially available leucocyte filters. Analysis of pre- and post-filtration samples by PCR with ethidium bromide staining has shown that filtration was successful in removing CMV DNA from all samples. This is evidence that leucocyte filtration of red cell concentrates may greatly decrease the risk of CMV disease following transfusion to susceptible patients.

  13. Application of the Na+ recirculation theory to ion coupled water transport in low- and high resistance osmoregulatory epithelia

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Møbjerg, Nadja; Nielsen, Robert

    2007-01-01

    The theory of Na+ recirculation for isosmotic fluid absorption follows logically from Hertz's convection-diffusion equation applied to the exit of water and solutes from the lateral intercellular space. Experimental evidence is discussed indicating Na+ recirculation based upon the following...

  14. The accumulation of substances in Recirculating Aquaculture Systems (RAS) affects embryonic and larval development in common carp Cyprinus carpio

    NARCIS (Netherlands)

    Martins, C.I.; Pristin, M.G.; Ende, S.S.W.; Eding, E.H.; Verreth, J.A.J.

    2009-01-01

    The accumulation of substances in Recirculating Aquaculture Systems (RAS) may impair the growth and welfare of fish. To test the severity of contaminants accumulated in RAS, early-life stages of fish were used. Ultrafiltered water from two Recirculating Aquaculture Systems (RAS), one RAS with a high

  15. An evaluation of a micro programmable logic controller for oxygen monitoring and control in tanks of a recirculating aquaculture system

    Science.gov (United States)

    Control of dissolved gases, especially oxygen is an essential component of recirculating aquaculture systems. The use of pure oxygen in a recirculating aquaculture system creates supersaturated concentrations of dissolved oxygen and can reduce fish production costs by supporting greater fish and fee...

  16. Proceedings of the fifteenth DOE nuclear air cleaning conference

    Energy Technology Data Exchange (ETDEWEB)

    First, M.W. (ed.)

    1979-02-01

    Papers presented are grouped under the following topics: noble gas separation, damage control, aerosols, test methods, new air cleaning technology from Europe, open-end, and filtration. A separate abstract was prepared for each paper.

  17. Radiation dose reduction without compromise to image quality by alterations of filtration and focal spot size in cerebral angiography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Joon; Park, Min Keun; Jung, Da Eun; Kang, Jung Han; Kim, Byung Moon [Dept. of Radiology, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2017-08-01

    Different angiographic protocols may influence the radiation dose and image quality. In this study, we aimed to investigate the effects of filtration and focal spot size on radiation dose and image quality for diagnostic cerebral angiography using an in-vitro model and in-vivo patient groups. Radiation dose and image quality were analyzed by varying the filtration and focal spot size on digital subtraction angiography exposure protocols (1, inherent filtration + large focus; 2, inherent + small; 3, copper + large; 4, copper + small). For the in-vitro analysis, a phantom was used for comparison of radiation dose. For the in-vivo analysis, bilateral paired injections, and patient cohort groups were compared for radiation dose and image quality. Image quality analysis was performed in terms of contrast, sharpness, noise, and overall quality. In the in-vitro analysis, the mean air kerma (AK) and dose area product (DAP)/frame were significantly lower with added copper filtration (protocols 3 and 4). In the in-vivo bilateral paired injections, AK and DAP/frame were significantly lower with filtration, without significant difference in image quality. The patient cohort groups with added filtration (protocols 3 and 4) showed significant reduction of total AK and DAP/patient without compromise to the image quality. Variations in focal spot size showed no significant differences in radiation dose and image quality. Addition of filtration for angiographic exposure studies can result in significant total radiation dose reduction without loss of image quality. Focal spot size does not influence radiation dose and image quality. The routine angiographic protocol should be judiciously investigated and implemented.

  18. Temperature and Humidity Control in Air-Conditioned Buildings with lower Energy Demand and increased Indoor Air Quality

    DEFF Research Database (Denmark)

    Paul, Joachim; Martos, E. T.

    2003-01-01

    %. For indoor air temperature and humidity control, the use of an ice slurry (´Binary Ice´)was compared to conventional chilled water. The use of Binary Ice instead of chilled water makes the air handling and air distribution installation much simpler, recirculation of air becomes obsolete, and a higher portion....... Binary Ice as secondary refrigerant for air-conditioning purposes is an economical and technically feasible solution in any climate. Whatever chilled water can do in an air-conditioning installation ? Binary Ice can do it better....... of ambient air can be supplied, thus improving the indoor air quality still further. Reheating of air is not necessary when using Binary Ice. The introduction of chilled air into a room requires a different type of air outlet, however. When using Binary Ice, energy savings are high for climates with low...

  19. Research on Testing Methods of Recirculation Filtration Fume Hood%再循环自净型排风柜检测方法的分析研究

    Institute of Scientific and Technical Information of China (English)

    刘东; 程勇; 李斯玮; 王新林

    2011-01-01

    在分析常规检测方法弊端的基础上,提出以环己烷、异丙醇或盐酸溶液代替SF6作为示踪气体,将吸附过滤器吸附量检测和控制浓度检测有机结合起来的一种改良检测方法;并从必要性、技术性和经济性角度分析了该检测方法用以检测再循环自净型排风柜的可行性和合理性.

  20. Membraneless water filtration using CO2

    Science.gov (United States)

    Shin, Sangwoo; Shardt, Orest; Warren, Patrick; Stone, Howard

    2016-11-01

    Water purification technologies such as ultrafiltration and reverse osmosis utilize porous membranes to remove suspended particles and solutes. These membranes, however, cause many drawbacks such as a high pumping cost and a need for periodic replacement due to fouling. Here we show an alternative membraneless method for separating suspended particles by exposing the colloidal suspension to CO2. Dissolution of CO2 into the suspension creates solute gradients that drive phoretic motion of particles, or so-called diffusiophoresis. Due to the large diffusion potential built up by the dissociation of carbonic acid, colloidal particles move either away from or towards the gas-liquid interface depending on their surface charge. Our findings suggest a means to separate particles without membranes or filters, thus reducing operating and maintenance costs. Using the directed motion of particles induced by exposure to CO2, we demonstrate a scalable, continuous flow, membraneless particle filtration process that exhibits very low pressure drop and is essentially free from fouling.

  1. Dynamical Systems, Cytokine Storms, and Blood Filtration

    Science.gov (United States)

    Foster, Glenn; Hubler, Alfred

    2008-03-01

    Various infections and non-infectious diseases can trigger immune cells and the proteins (cytokines) the cells use to communicate with each other to be caught in a positive feedback loop; this ``cytokine storm'' is frequently fatal. By examining the network of cytokine-immune cell interactions we will illustrate why anti-mediator drugs have been generally ineffective in stopping this feedback. A more effective approach may be to try and reduce interactions by dampening many signals at once by filtering the cytokines out of the blood directly (think dialysis). We will argue that feedback on an out of control nonlinear dynamical system is easier to understand than its normal healthy state and apply filtration to a toy model of immune response.

  2. Pattern recognition using inverse resonance filtration

    CERN Document Server

    Sofina, Olga; Kvetnyy, Roman

    2010-01-01

    An approach to textures pattern recognition based on inverse resonance filtration (IRF) is considered. A set of principal resonance harmonics of textured image signal fluctuations eigen harmonic decomposition (EHD) is used for the IRF design. It was shown that EHD is invariant to textured image linear shift. The recognition of texture is made by transfer of its signal into unstructured signal which simple statistical parameters can be used for texture pattern recognition. Anomalous variations of this signal point on foreign objects. Two methods of 2D EHD parameters estimation are considered with the account of texture signal breaks presence. The first method is based on the linear symmetry model that is not sensitive to signal phase jumps. The condition of characteristic polynomial symmetry provides the model stationarity and periodicity. Second method is based on the eigenvalues problem of matrices pencil projection into principal vectors space of singular values decomposition (SVD) of 2D correlation matrix....

  3. Gravity filtration of suspensions: permeability effects

    Science.gov (United States)

    Soori, Tejaswi; Wang, Mengyu; Ward, Thomas

    2015-11-01

    This paper examines the filtration rates of mono-modal suspensions as a function of time and a cake layer builds up through theory and experimentation. Darcy's Law, which describes fluid flow through porous media, was applied along with the Kynch theory of sedimentation, which provides the basis for analyzing low concentration (ϕ filter media. A CCD camera was used to capture images of the cake formation and fluid drainage processes, and subsequent image and theoretical analysis found the fluid flow experienced a constant pressure loss due to the permeability of the filter media, whereas the experienced pressure loss due to the cake formation varies as a function of time, ϕ and d. The rate of cake formation was also found to be independent of ϕ but dependent on d which can be attributed to a change in porosity affecting permeability. Studies on similar systems with multi-modal suspensions are in-progress.

  4. Disinfection of water in recirculating aquaculture systems with peracetic acid (PAA)

    Science.gov (United States)

    The disinfection behaviour of peracetic acid (PAA) in recirculating aquaculture systems (RAS) was investigated. Peracetic acid is a strong oxidizing agent found in various concentrations in different products. Three Wofasteril PAA products (E400 (c), Lspecical; AC 150) were tested in vitro for the...

  5. Exhaust Gas Recirculation Control for Large Diesel Engines - Achievable Performance with SISO Design

    DEFF Research Database (Denmark)

    Hansen, Jakob Mahler; Blanke, Mogens; Niemann, Hans Henrik

    2013-01-01

    This paper investigates control possibilities for Exhaust Gas Recirculation (EGR) on large diesel engines. The goal is to reduce the amount of NOx in the exhaust gas by reducing the oxygen concentration available for combustion. Control limitations imposed by the system are assessed using linear...

  6. Investigation of proper modeling of very dense granular flows in the recirculation system of CFBs

    Institute of Scientific and Technical Information of China (English)

    Aristeidis Nikolopoulos; Nikos Nikolopoulos; Nikos Varveris; Sotirios Karellas; Panagiotis Grammelis; Emmanuel Kakaras

    2012-01-01

    The aim of this paper is the development of new models and/or the improvement of existing numerical models,used for simulating granular flow in CFB (circulating fluidized bed) recirculation systems.Most recent models follow the TFM (two-fluid model) methodology,but they cannot effectively simulate the inter-particle friction forces in the recirculation system,because the respective stress tensor does not incorporate compressibility of flow due to change of effective particle density.As a consequence,the induced normal and shear stresses are not modeled appropriately during the flow of the granular phase in the CFB recirculation system.The failure of conventional models,such as that of von Mises/Coulomb,is mainly caused by false approximation of the yield criterion which is not applicable to the CFB recirculation system.The present work adopts an alternative yield function,used for the first time in TFM Eulerian modeling.The proposed model is based on the Pitman-Schaeffer-Gray-Stiles yield criterion.Both the temporal deformation of the solid granular phase and the repose angle that the granular phase forms are more accurately simulated by this model.The numerical results of the proposed model agree well with experimental data,implying that frictional forces are efficiently simulated by the new model.

  7. CCR7 Controls Thymus Recirculation, but Not Production and Emigration, of Foxp3(+) T Cells.

    Science.gov (United States)

    Cowan, Jennifer E; McCarthy, Nicholas I; Anderson, Graham

    2016-02-09

    Current models of Foxp3(+) regulatory T cell (Treg) development involve CCR7-mediated migration of thymocytes into the thymus medulla to enable essential interactions with medullary epithelium. However, increased Foxp3(+) thymic Treg numbers in Ccr7(-/-) mice challenge this view, and the role of CCR7 in Treg development, emigration, and/or recirculation is unknown. Here, we have examined CCR7 and Rag2pGFP levels during Treg development and generated Rag2pGFPCcr7(-/-) mice to study its impact on the intrathymic Treg pool. We reveal surprising developmental heterogeneity in thymocytes described as Treg precursors, showing that they contain recirculating CCR6(+)CCR7(-)Rag2pGFP(-) T cells. Although CCR7 defines bona fide Rag2GFP(+) Treg precursors, it is not required for Treg production and emigration. Rather, we show that lack of CCR7 renders the thymus more receptive to Treg thymus homing. Our study reveals a role for CCR7 in limiting Treg recirculation back to the thymus and enables separation of the mechanisms controlling Treg production and thymic recirculation.

  8. HRT and nutrients affect bacterial communities grown on recirculation aquaculture system effluents

    NARCIS (Netherlands)

    Schneider, O.; Chabrillon-Popelka, M.; Smidt, H.; Haenen, O.L.M.; Sereti, V.; Eding, E.H.; Verreth, J.A.J.

    2007-01-01

    In a recirculation aquaculture system the drumfilter effluent can be used as substrate for heterotrophic bacterial production, which can be recycled as feed. Because the bacteria might contain pathogens, which could reduce its suitability as feed, it is important to characterize these communities. B

  9. Control-Oriented Model of Molar Scavenge Oxygen Fraction for Exhaust Recirculation in Large Diesel Engines

    DEFF Research Database (Denmark)

    Nielsen, Kræn Vodder; Blanke, Mogens; Eriksson, Lars;

    2016-01-01

    Exhaust gas recirculation (EGR) systems have been introduced to large marine engines in order to reduce NOx formation. Adequate modelling for control design is one of the bottlenecks to design EGR control that also meets emission requirements during transient loading conditions. This paper...

  10. Optimization of blue mussel (Mytilus edulis) seed culture using recirculation aquaculture systems

    NARCIS (Netherlands)

    Blanco Garcia, A.; Kamermans, P.

    2015-01-01

    By introducing recirculation aquaculture systems (RAS) in the nursery phase of the blue mussel (Mytilus edulis) (17–18 mm), we aimed at a similar growth and survival and a similar water quality compared to the commonly used flow-through systems (FTS). To calculate water flow and size of the biofilte

  11. Recirculating linacs for a neutrino factory--Arc optics design and optimization

    CERN Document Server

    Bogacz, S A

    2001-01-01

    A conceptual lattice design for a muon accelerator based on recirculating linacs (Nucl. Instr. and Meth. A 472 (2001) 499, these proceedings) is presented here. The challenge of accelerating and transporting a large phase space of short-lived muons is answered here by presenting a proof-of-principle lattice design for a recirculating linac accelerator. It is the centerpiece of a chain of accelerators consisting of a 3 GeV linac and two consecutive recirculating linear accelerators, which facilitates acceleration starting after ionization cooling at 190 MeV/c and proceeding to 50 GeV. Beam transport issues for large-momentum-spread beams are accommodated by appropriate lattice design choices. The resulting arc optics is further optimized with a sextupole correction to suppress chromatic effects contributing to the emittance dilution. The presented proof-of-principle design of the arc optics with horizontal separation of multi-pass beams can be extended to all passes in both recirculating linacs.

  12. Low-dose hydrogen peroxide application in closed recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Pedersen, Lars-Flemming; Good, C.; Pedersen, Per Bovbjerg

    2012-01-01

    The aim of the present work was to simulate water treatment practices with hydrogen peroxide (HP) in recirculating aquaculture systems (RAS). Six identical 1,700-L pilot-scale RAS were divided into two experimental groups based on daily feed allocation and operated under constant conditions...

  13. Improving sustainability of striped catfish (Pangasianodon hypophthalmus) farming in the Mekong Delta, Vietnam through recirculation technology

    NARCIS (Netherlands)

    Nguyen, Nhut

    2016-01-01

    The aim of this thesis was to document improvements in sustainability indicators of striped catfish (Pangasianodon hypophthalmus, Sauvage, 1878) production through the application of recirculation and waste treatment techniques. To be able to document improvements in sustainability, in each system s

  14. Adoption of Recirculating Aquaculture Systems in Pangasius Farms: A Choice Experiment

    NARCIS (Netherlands)

    Pham, T.A.N.; Gielen-Meuwissen, M.P.M.; Le, T.T.; Bosma, R.H.; Oude Lansink, A.G.J.M.

    2015-01-01

    A growing number of European customers’ demands certified pangasius such as ASC in order to ensure sustainable production. Implementing Recirculating Aquaculture Systems (RAS) contributes to an improved water quality, a key issue in achieving ASC certification. This study uses a choice experiment to

  15. Adoption of Recirculating Aquaculture Systems in Large Pangasius Farms: A Choice Experiment

    NARCIS (Netherlands)

    Pham, T.A.N.; Gielen-Meuwissen, M.P.M.; Le, T.C.; Verreth, J.A.J.; Bosma, R.H.; Oude Lansink, A.G.J.M.

    2016-01-01

    A growing number of European customers’ demands certified pangasius such as ASC in order to ensure sustainable production. Implementing Recirculating Aquaculture Systems (RAS) contributes to an improved water quality, a key issue in achieving ASC certification. This study uses a choice experiment to

  16. Removal of Nutrients from Septic Effluent with Re-circulated Hybrid Tidal Flow Constructed Wetland

    Science.gov (United States)

    Lihua Cui; Jigkun Feng; Ying Ouyang; Peiwen. Deng

    2012-01-01

    Hybrid tidal flow constructed wetland (CW) with recirculation is an improved biological and engineering technique for removal of excess nutrients and certain pollutants from wastewater. This study investigated the removal efficiency of total phosphorus (TP), ammonia-nitrogen (NH3-N), and total nitrogen (TN) from septic tank effluent with the hybrid tidal flow CW system...

  17. Multi-point optimization of recirculation flow type casing treatment in centrifugal compressors

    Science.gov (United States)

    Tun, Min Thaw; Sakaguchi, Daisaku

    2016-06-01

    High-pressure ratio and wide operating range are highly required for a turbocharger in diesel engines. A recirculation flow type casing treatment is effective for flow range enhancement of centrifugal compressors. Two ring grooves on a suction pipe and a shroud casing wall are connected by means of an annular passage and stable recirculation flow is formed at small flow rates from the downstream groove toward the upstream groove through the annular bypass. The shape of baseline recirculation flow type casing is modified and optimized by using a multi-point optimization code with a metamodel assisted evolutionary algorithm embedding a commercial CFD code CFX from ANSYS. The numerical optimization results give the optimized design of casing with improving adiabatic efficiency in wide operating flow rate range. Sensitivity analysis of design parameters as a function of efficiency has been performed. It is found that the optimized casing design provides optimized recirculation flow rate, in which an increment of entropy rise is minimized at grooves and passages of the rotating impeller.

  18. Access recirculation in a native fistula in spite of a seemingly adequate access flow

    NARCIS (Netherlands)

    Haas, Mark; Spargo, Benjamin H.; Wit, Ernst-Jan C.; Meehan, Shane M.

    2000-01-01

    True access recirculation (AR) measured by ultrasound dilution technique is usually absent in well-working shunts. It occurs with low access flows (Qa). High access flow rates are assumed to prevent AR. Two major exceptions to these rules are known: presence of intra-access strictures and inadverten

  19. Building America Case Study: Control Retrofits for Multifamily Domestic Hot Water Recirculation Systems, Brooklyn, New York

    Energy Technology Data Exchange (ETDEWEB)

    2016-12-01

    Domestic hot water (DHW) heating is the second largest energy end use in U.S. buildings, exceeded only by space conditioning. Recirculation systems consisting of a pump and piping loop(s) are commonly used in multifamily buildings to reduce wait time for hot water at faucets; however, constant pumping increases energy consumption by exposing supply and return line piping to continuous heat loss, even during periods when there is no demand for hot water. In this study, ARIES installed and tested two types of recirculation controls in a pair of buildings in order to evaluate their energy savings potential. Demand control, temperature modulation controls, and the simultaneous operation of both were compared to the baseline case of constant recirculation. Additionally, interactive effects between DHW control fuel reductions and space conditioning (heating and cooling) were estimated in order to make more realistic predictions of the payback and financial viability of retrofitting DHW systems with these controls. Results showed that DHW fuel consumption reduced by 7 percent after implementing the demand control technique, 2 percent after implementing temperature modulation, and 15 percent after implementing demand control and temperature modulation techniques simultaneously; recirculation pump runtime was reduced to 14 minutes or less per day. With space heating and cooling interactions included, the estimated annual cost savings were 8 percent, 1 percent, and 14 percent for the respective control techniques. Possible complications in the installation, commissioning and operation of the controls were identified and solutions offered.

  20. Nitrate removal effectiveness of fluidized sulfur-based autotrophic denitrification biofilters for recirculating aquaculture systems

    Science.gov (United States)

    There is a need to develop practical methods to reduce nitrate -nitrogen loads from recirculating aqua-culture systems to facilitate increased food protein production simultaneously with attainment of water quality goals. The most common wastewater denitrification treatment systems utilize methanol-...

  1. Water cortisol and testosterone in Nile tilapia (Oreochromis niloticus) recirculating aquaculture systems

    NARCIS (Netherlands)

    Mota, Vasco C.; Martins, Catarina I.M.; Eding, Ep H.; Canário, Adelino V.M.; Verreth, Johan A.J.

    2017-01-01

    The accumulation of steroids released by fish in recirculating aquaculture systems (RAS) may potentially influence their physiology and behavior. The present study examined the release rate of cortisol and testosterone by Nile tilapia, Oreochromis niloticus, and their accumulation in six identical

  2. Researchers evaluate low-energy recirculating system for inland production of marine finfish juveniles

    Science.gov (United States)

    The low-energy recirculating aquaculture system consists of nine separate modules which utilize the double drain fish culture tank paired to a moving bed biofilter. The nine fiberglass tanks are five feet in diameter and normal water depth is about three feet for a total tank volume of approximately...

  3. Experimental Bleaching of a Reef-Building Coral Using a Simplified Recirculating Laboratory Exposure System

    Science.gov (United States)

    Determining stressor-response relationships in reef building corals is a critical need for researchers because of global declines in coral reef ecosystems. A simplified recirculating coral exposure system for laboratory testing of a diversity of species and morphologies of reef b...

  4. Experimental Bleaching of a Reef-Building Coral Using a Simplified Recirculating Laboratory Exposure System

    Science.gov (United States)

    Determining stressor-response relationships in reef building corals is a critical need for researchers because of global declines in coral reef ecosystems. A simplified recirculating coral exposure system for laboratory testing of a diversity of species and morphologies of reef b...

  5. Performance evaluation of Large Eddy Simulation for recirculating and swirling flows

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Cheol Hong; Lee, Chang Eon [Inha University, Incheon (Korea, Republic of)

    2006-04-15

    The objective of this study is to evaluate the efficiency and the prediction accuracy of developed Large Eddy Simulation (LES) program for complex turbulent flows, such as recirculating and swirling flows. To save the computational cost, a Beowulf cluster system consisting 16 processors was constructed. The flows in backward-facing step and dump combustor were examined as representative recirculating and swirling flows. Firstly, a Direct Numerical Simulation (DNS) for laminar backward-facing step flows was previously conducted to validate the overall performance of program. Then LES was carried out for turbulent backward-facing step flows. The results of laminar flow showed a qualitative and quantitative agreement between simulations and experiments. The simulations of the turbulent flow also showed reasonable results. Secondly, LES results for non-swirling and swirling flows in a dump combustor were compared with the results of Reynolds-Averaged Navier-Stokes (RANS) using standard {kappa}-{epsilon} model. The results show that LES has a better performance in predicting the mean axial and azimuthal velocities, Corner Recirculation Zone (CRZ) and Center Toroidal Recirculation Zone (CTRZ) than those of RANS. Finally, it was examined the capability of LES for the description of unsteady phenomena.

  6. The benefits of powdered activated carbon recirculation for micropollutant removal in advanced wastewater treatment.

    Science.gov (United States)

    Meinel, F; Zietzschmann, F; Ruhl, A S; Sperlich, A; Jekel, M

    2016-03-15

    PAC adsorption is a widespread option for the removal of organic micropollutants (OMP) from secondary effluent. For an optimal exploitation of the adsorption capacity, PAC recirculation is nowadays a common practice, although the mechanistic interrelations of the complex recirculation process are not fully resolved. In this work, extensive multi-stage batch adsorption testing with repeated PAC and coagulant dosage was performed to evaluate the continuous-flow recirculation system. Partly loaded PAC showed a distinct amount of remaining capacity, as OMP and DOC removals considerably increased with each additional adsorption stage. At a low PAC dose of 10 mg PAC L(-1), removals of benzotriazole and carbamazepine were shown to rise from 80% in the 11th stage at 30 min adsorption time per stage. At a high PAC dose of 30 mg PAC L(-1), OMP and DOC removals were significantly higher and reached 98% (for benzotriazole and carbamazepine) after 11 stages. Coagulant dosage showed no influence on OMP removal, whereas a major part of DOC removal can be attributed to coagulation. Multi-stage adsorption is particularly beneficial for small PAC doses and significant PAC savings are feasible. A new model approach for predicting multi-stage OMP adsorption on the basis of a single-stage adsorption experiment was developed. It proved to predict OMP removals and PAC loadings accurately and thus contributes towards understanding the PAC recirculation process.

  7. Mixing and Recirculation Characteristics of A double COncentric Burner with Bluff—Body

    Institute of Scientific and Technical Information of China (English)

    H.K.Ma; C.H.Chiou; 等

    1993-01-01

    The concentric bluff-body jet burner is widely used in industrial combustion systems.This kind of burner often generates a considerably complex recirculation zone behind the bluff body.As a result,the fuel often remains in the recirculation zone,achieving stability of flame.This study investigates,by means of experiments,the variations of the aerodynamics as the fluid is injected into a combustion chamber through a doble concentric burner with a bluff-body.The observation and measurement of the aerodynamics in our experiment are conducted under a cold flow.The controlled parameters in our experiment are:variations in the blockage ratio of the center bluff body,the cone angle of the bluff body,and the velocity ratio(Us/Up) of the secondary jet and primary jet;the injection of helium bubbles into the primary and secondary jets to observe the recirculation zone behind the bluff body;using Tufts for obseving the characteristics of corner recirculation zone in a combustion chamber,measuring the average velocity of each point within the aerodynamics by the 5-hole pitot tube;measuring the distribution of static pressure of the combustion chamber walls with a static pressure tap.

  8. Removal of nitrogen by Algal Turf Scrubber Technology in recirculating aquaculture system

    NARCIS (Netherlands)

    Valeta, J.; Verdegem, M.C.J.

    2015-01-01

    Ongoing research in recirculation aquaculture focuses on evaluating and improving the purification potential of different types of filters. Algal Turf Scrubber (ATS) are special as they combine sedimentation and biofiltration. An ATS was subjected to high nutrient loads of catfish effluent to examin

  9. Removal of nitrogen by Algal Turf Scrubber Technology in recirculating aquaculture system

    NARCIS (Netherlands)

    Valeta, J.; Verdegem, M.C.J.

    2015-01-01

    Ongoing research in recirculation aquaculture focuses on evaluating and improving the purification potential of different types of filters. Algal Turf Scrubber (ATS) are special as they combine sedimentation and biofiltration. An ATS was subjected to high nutrient loads of catfish effluent to

  10. Geophysical monitoring of recirculation of leachate on landfill sites in the Netherlands

    NARCIS (Netherlands)

    Kruiver, P.P.; Westerhoff, R.S.; Noorlandt, R.P.; Hoekstra, N.N.; Woelders, H.; Vossen, W.J. van

    2009-01-01

    Geophysical investigations were carried out on two modern landfill sites in the Netherlands. The objective of the geo-electrical and EM31 measurements was to reveal the effect of recirculation of leachate on homogenising moisture content in the waste to stimulate the process of attenuation. At Vlagh

  11. Gas transfer rates from airlifts used for concurrent aeration, carbon dioxide stripping, and recirculation

    Science.gov (United States)

    Airlifts simplify recirculating aquaculture systems and can potentially reduce capital costs and minimize maintenance issues. Airlifts have the ability to move and aerate water as well as degass the water of any carbon dioxide. This study evaluated the oxygen transfer and carbon dioxide removal abil...

  12. Geosmin causes off-flavour in arctic charr in recirculating aquaculture systems

    Science.gov (United States)

    The “earthy” and “muddy” off-flavors in pond-reared fish are due to the presence of geosmin or 2-methylisoborneol (MIB) in the flesh of the fish. Similar off-flavors have been reported in fish raised in recirculating aquaculture systems (RAS); however, little information is available regarding the ...

  13. Water cortisol and testosterone in Nile tilapia (Oreochromis niloticus) recirculating aquaculture systems

    NARCIS (Netherlands)

    Mota, Vasco C.; Martins, Catarina I.M.; Eding, Ep H.; Canário, Adelino V.M.; Verreth, Johan A.J.

    2017-01-01

    The accumulation of steroids released by fish in recirculating aquaculture systems (RAS) may potentially influence their physiology and behavior. The present study examined the release rate of cortisol and testosterone by Nile tilapia, Oreochromis niloticus, and their accumulation in six identical l

  14. Solids removal from a coldwater recirculating system - comparison of swirl separator and radial-flow settlers

    Science.gov (United States)

    Solids removal across two settling devices, i.e., a swirl separator and a radial-flow settler, and across a microscreen drum filter was evaluated in a fully recirculating system containing a single 150 m3 'Cornell-type' dual-drain tank during the production of food-size Arctic char and rainbow trout...

  15. Observations on side-swimming rainbow trout Oncorhynchus mykiss in water recirculation aquaculture systems

    Science.gov (United States)

    During a controlled 6-month study using six replicated water recirculation aquaculture systems (WRAS), it was observed that rainbow trout Oncorhynchus mykiss in all WRAS exhibited a higher-than-normal prevalence of side-swimming (i.e. controlled, forward swimming, but with misaligned orientation suc...

  16. Anaerobic Digestion of the Organic Fraction of Municipal Solid Waste With Recirculation of Process Water

    DEFF Research Database (Denmark)

    Hartmann, H.; Angelidaki, Irini; Ahring, Birgitte Kiær

    2001-01-01

    A new concept of a wet anaerobic digestion treatment of the organic fraction of municipal solid waste (OFMSW) is investigated. Once the waste is diluted with water, the entire liquid fraction of the effluent is recirculated and used as process water for dilution of the waste. This enables a well...

  17. The Effect of Effluent Recirculation in a Semi-Continuous Two-Stage Anaerobic Digestion System

    Directory of Open Access Journals (Sweden)

    Karthik Rajendran

    2013-06-01

    Full Text Available The effect of recirculation in increasing organic loading rate (OLR and decreasing hydraulic retention time (HRT in a semi-continuous two-stage anaerobic digestion system using stirred tank reactor (CSTR and an upflow anaerobic sludge bed (UASB was evaluated. Two-parallel processes were in operation for 100 days, one with recirculation (closed system and the other without recirculation (open system. For this purpose, two structurally different carbohydrate-based substrates were used; starch and cotton. The digestion of starch and cotton in the closed system resulted in production of 91% and 80% of the theoretical methane yield during the first 60 days. In contrast, in the open system the methane yield was decreased to 82% and 56% of the theoretical value, for starch and cotton, respectively. The OLR could successfully be increased to 4 gVS/L/day for cotton and 10 gVS/L/day for starch. It is concluded that the recirculation supports the microorganisms for effective hydrolysis of polyhydrocarbons in CSTR and to preserve the nutrients in the system at higher OLRs, thereby improving the overall performance and stability of the process.

  18. Pilot-scale study of powdered activated carbon recirculation for micropollutant removal.

    Science.gov (United States)

    Meinel, F; Sperlich, A; Jekel, M

    Adsorption onto powdered activated carbon (PAC) is a promising technique for the removal of organic micropollutants (OMPs) from treated wastewater. To enhance the adsorption efficiency, PAC is recycled back into the adsorption stage. This technique was examined in pilot scale in comparison to a reference without recirculation. Coagulation with Fe(3+) was carried out simultaneously to adsorption. Extensive OMP measurements showed that recirculation significantly increased OMP eliminations. Thus, significant PAC savings were feasible. The PAC concentration in the contact reactor proved to be an important operating parameter that can be surrogated by the easily measurable total suspended solids (TSS) concentration. OMP eliminations increased with increasing TSS concentrations. At 20 mg PAC L(-1) and 2.8 g TSS L(-1) in the contact reactor, well-adsorbable carbamazepine was eliminated by 97%, moderately adsorbable diclofenac was eliminated by 92% and poorly-adsorbable acesulfame was eliminated by 54% in comparison to 49%, 35% and 18%, respectively, without recirculation. The recirculation system represents an efficient technique, as the PAC's adsorption capacity is practically completely used. Small PAC dosages yield high OMP eliminations. Poorly-adsorbable gabapentin was eliminated to an unexpectedly high degree. A laboratory-scale biomass inhibition study showed that aerobic biodegradation removed gabapentin in addition to adsorption.

  19. Facilities and techniques for indoor recirculating aquaculture of clownfish%小丑鱼室内循环水养殖设施与技术

    Institute of Scientific and Technical Information of China (English)

    单乐州; 邵鑫斌; 曹醒戈

    2016-01-01

    为了实现规模化人工养殖小丑鱼( Amphiprioninae),研发了小丑鱼室内循环水养殖设施和技术。1组循环水养殖系统由10个玻璃钢养殖桶和1个水处理玻璃缸及管道系统组成,采用物理过滤、生化过滤、藻板过滤进行循环水处理。1组循环水养殖系统每3个月可养殖产出全长约3.5 cm的商品小丑鱼5000尾,养殖存活率达80%以上。从2014年至2015年,利用该设施养殖生产出商品小丑鱼10余万尾。和常规的食用海水鱼循环水养殖设施相比,小丑鱼室内循环水养殖系统主要减少了蛋白分离器、气浮机、微滤机等设备,增加了藻板过滤设施。研究表明,小丑鱼室内循环水养殖系统建造成本低、运行能耗低、管理维护简单、水质稳定,可基本实现全封闭循环水养殖,适合进行小丑鱼等海水珊瑚礁观赏鱼类的规模化养殖生产。%In order to produce marketable clownfish in large scale, facilities and techniques for indoor recirculating aquaculture of sea-water clownfish were developed.One group clownfish recirculating aquaculture system was composed of 10 round fiberglass tanks, 1 fibre glass tank for waster water purification and piping system.Physical filtering, biochemical filtering, and plastic algal plate filtering were adopted for circulating watzer purification.One group system could produce 5,000 marketable clownfish with size of 3.5 cm in total length in 3 months, and the survival rate was above 80%.More than 100,000 marketable clownfish have been produced from 2014 to 2015 in these systems. Compared with the conventional seawater edible fish recirculating aquaculture system, the indoor recirculating aquaculture system of clownfish reduced the protein separator or air flotation equipment and microfiltration machine, and supplement the plastic algal plate filtering system.The research showed that the indoor recirculating aquaculture system of clownfish was

  20. Investigation of Saltwater Intrusion and Recirculation of Seawater at a Coastal Boundary

    Science.gov (United States)

    Motz, L. H.; Sedighi, A.

    2012-12-01

    Numerical experiments were conducted to investigate saltwater intrusion and recirculation of seawater at a coastal boundary. A field-scale two-dimensional cross-section was simulated in which freshwater inflow occurred at an upgradient boundary, and saltwater inflow and freshwater outflow and recirculated seawater outflow occurred at a downgradient coastal boundary. The upgradient boundary is a specified-flux boundary with a zero freshwater concentration, and the downgradient boundary is a specified-head boundary with a specified saltwater concentration. This problem was solved using the numerical groundwater flow and transport code SEAWAT for two conditions, i.e., first for the uncoupled condition in which the fluid density is constant and thus the flow and transport equations are uncoupled in a constant-density flowfield, and then for the coupled condition in which the fluid density is a function of the total dissolved solids concentration and thus the flow and transport equations are coupled in a variable-density flowfield. Equivalent freshwater heads were specified at the downstream boundary for both conditions to account for density differences between freshwater and saltwater at the downstream boundary. A range of results for the landward extent of saltwater intrusion and the amount of recirculation of seawater at the coastal boundary was obtained by varying the independent dimensionless ratio of the freshwater inflow relative to the density-driven buoyancy flux, defined as az. For both coupled and uncoupled conditions, it was determined that saltwater intrusion and seawater recirculation are decreased significantly as az is increased. However, the extent of saltwater intrusion is less and the degree of seawater recirculation is greater for the uncoupled condition compared to the coupled condition at smaller values of az, indicating that significant differences can occur between uncoupled and coupled simulations. For the experiments conducted in this

  1. Life Support Filtration System Trade Study for Deep Space Missions

    Science.gov (United States)

    Agui, Juan H.; Perry, Jay L.

    2017-01-01

    The National Aeronautics and Space Administrations (NASA) technical developments for highly reliable life support systems aim to maximize the viability of long duration deep space missions. Among the life support system functions, airborne particulate matter filtration is a significant driver of launch mass because of the large geometry required to provide adequate filtration performance and because of the number of replacement filters needed to a sustain a mission. A trade analysis incorporating various launch, operational and maintenance parameters was conducted to investigate the trade-offs between the various particulate matter filtration configurations. In addition to typical launch parameters such as mass, volume and power, the amount of crew time dedicated to system maintenance becomes an increasingly crucial factor for long duration missions. The trade analysis evaluated these parameters for conventional particulate matter filtration technologies and a new multi-stage particulate matter filtration system under development by NASAs Glenn Research Center. The multi-stage filtration system features modular components that allow for physical configuration flexibility. Specifically, the filtration system components can be configured in distributed, centralized, and hybrid physical layouts that can result in considerable mass savings compared to conventional particulate matter filtration technologies. The trade analysis results are presented and implications for future transit and surface missions are discussed.

  2. Vibrating membrane filtration as improved technology for microalgae dewatering.

    Science.gov (United States)

    Nurra, Claudia; Clavero, Ester; Salvadó, Joan; Torras, Carles

    2014-04-01

    The effect of shear-enhanced filtration by vibratory process in microalgae dewatering is presented in this paper. The aim of this research was to investigate the technical performance and improvement of vibrating membrane filtration compared with conventional tangential cross-flow filtration in microalgae concentration. An industrial-scale available commercial set-up was used. Several membrane materials as polyethersulfone, polyacrylonitrile, etc., and mean pore sizes (from 7000Da to 0.2μm) were tested and compared in both filtration set-ups. Experiments were carried-out with Nannochloropsis gaditana and Phaeodactylum tricornutum microalgae. It has been demonstrated that, even if the choice of the membrane depends on its cut-off, its material and the type of microalgae filtrated, dynamic filtration is always the best technology over a conventional one. If with conventional filtration permeability values were in the vicinity of 10L/h/m(2)/bar in steady state phase, with dynamic filtration these values increased to 30L/h/m(2)/bar or more.

  3. Analysis of the Medium Resistance for Constant Pressure Filtration

    Institute of Scientific and Technical Information of China (English)

    吴燕翔; 王碧玉

    2004-01-01

    A mathematical model for constant pressure filtration is established. The distribution of hydraulic pressure within the cake and the medium resistance are measured. The medium resistance Rm is calculated from the suppositional filtration time Ore. It is demonstrated that Rm is nearly a constant for a given filter cloth.

  4. Purification of contaminated water by filtration through porous glass

    Science.gov (United States)

    Wydeven, T.; Leban, M. I.

    1972-01-01

    Method for purifying water that is contaminated with mineral salts and soluble organic compounds is described. Method consists of high pressure filtration of contaminated water through stabilized porous glass membranes. Procedure for conducting filtration is described. Types of materials by percentage amounts removed from the water are identified.

  5. Scaling and particulate fouling in membrane filtration systems

    NARCIS (Netherlands)

    Boerlage, S.F.E.

    2001-01-01

    In the last decade, pressure driven membrane filtration processes; reverse osmosis, nano, ultra and micro-filtration have undergone steady growth. Drivers for this growth include desalination to combat water scarcity and the removal of various material from water to comply with increasingly stringen

  6. Scaling and particulate fouling in membrane filtration systems

    NARCIS (Netherlands)

    Boerlage, S.F.E.

    2001-01-01

    In the last decade, pressure driven membrane filtration processes; reverse osmosis, nano, ultra and micro-filtration have undergone steady growth. Drivers for this growth include desalination to combat water scarcity and the removal of various material from water to comply with increasingly

  7. Simulation of impaction filtration by a porous filter

    NARCIS (Netherlands)

    Ghazaryan, L.; Lopez Penha, D.J.; Geurts, B.J.; Stolz, S.; Winkelmann, C.; Vafai, K.

    2010-01-01

    We present a new numerical approach for estimating filtration through porous media from first principles. We numerically simulate particle motion as arises in a carrier gas flow. The filtration we look at occurs due to impaction of particles with obstructing surfaces that are contained in the solid

  8. Model and optimization of electromagnetic filtration of metals

    Directory of Open Access Journals (Sweden)

    S. Golak

    2013-04-01

    Full Text Available Electromagnetic buoyancy force causes the movement of non-conducive particles in a conducting liquid under electromagnetic field. The phenomenon allows filtration of small inclusions from molten metals. This paper presents a mathematical model of the filtration process under alternating electromagnetic field and the methodology for maximizing its efficiency.

  9. Performance of Water Recirculation Loop Maintentance Components for the Advanced Spacesuit Water Membrane Evaporator

    Science.gov (United States)

    Rector, Tony; Peyton, Barbara; Steele, John W.; Bue, Grant C.; Campbell, Colin; Makinen, Janice

    2014-01-01

    Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a second SWME water recirculation loop with no water quality maintenance. Results show the benefits of periodic water maintenance. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the evaluation of water recirculation maintenance components was to further enhance this advantage through the leveraging of fluid loop management lessonslearned from the International Space Station (ISS). A bed design that was developed for a UTAS military application, and considered for a potential ISS application with the Urine Processor Assembly, provided a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for ISS to introduce a biocide in a microgravity-compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

  10. Performance of Water Recirculation Loop Maintenance Components for the Advanced Spacesuit Water Membrane Evaporator

    Science.gov (United States)

    Rector, Tony; Peyton, Barbara M.; Steele, John W.; Makinen, Janice; Bue, Grant C.; Campbell, Colin

    2014-01-01

    Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a second SWME water recirculation loop with no water quality maintenance. Results show the benefits of periodic water maintenance. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the evaluation of water recirculation maintenance components was to further enhance this advantage through the leveraging of fluid loop management lessons learned from the International Space Station (ISS). A bed design that was developed for a UTAS military application, and considered for a potential ISS application with the Urine Processor Assembly, provided a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for ISS to introduce a biocide in a microgravity compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

  11. Physicochemical interaction and its influence on deep bed filtration process

    Institute of Scientific and Technical Information of China (English)

    GUO Jin-long; MENG Jun; LI GUI-ping; LUAN Zhao-kun; TANG Hong-xiao

    2004-01-01

    The capillary model was used to analyze the hydraulic conditions in the deep bed filtration process. Thephysicochemical interaction forces between the filter media and suspended particles and their influence on deep bedfiltration process were also studied theoretically. Through the comparison of the hydraulic and physicochemicalforces, the key influencing factors on the filtration process were proposed and investigated. Pilot study of the micro-flocculation deep bed filtration was carried out in the No. 9 Potable Water Treatment Plant of Beijing, and theexperimental results of hydraulic head loss, particle distribution and entrapment were presented. The theoreticalprediction was reasonably consistent with the experimental results under different conditions, which indicated that theregulation and control of micro-flocculation and deep bed filtration could be realized by the evaluation of thephysicochemical interactions. Further theoretical and experimental research should be carried out to investigate theinteraction mechanism and its application in the deep bed filtration and other cases.

  12. Wood dust particle and mass concentrations and filtration efficiency in sanding of wood materials.

    Science.gov (United States)

    Welling, Irma; Lehtimäki, Matti; Rautio, Sari; Lähde, Tero; Enbom, Seppo; Hynynen, Pasi; Hämeri, Kaarle

    2009-02-01

    The importance of fine particles has become apparent as the knowledge of their effects on health has increased. Fine particle concentrations have been published for outside air, plasma arc cutting, welding, and grinding, but little data exists for the woodworking industry. Sanding was evaluated as the producer of the woodworking industry's finest particles, and was selected as the target study. The number of dust particles in different particle size classes and the mass concentrations were measured in the following environments: workplace air during sanding in plywood production and in the inlet and return air; in the dust emission chamber; and in filter testing. The numbers of fine particles were low, less than 10(4) particles/cm(3) (10(7) particles/L). They were much lower than typical number concentrations near 10(6) particles/cm(3) measured in plasma arc cutting, grinding, and welding. Ultrafine particles in the size class less than 100 nm were found during sanding of MDF (medium density fiberboard) sheets. When the cleaned air is returned to the working areas, the dust content in extraction systems must be monitored continuously. One way to monitor the dust content in the return air is to use an after-filter and measure pressure drop across the filter to indicate leaks in the air-cleaning system. The best after-filtration materials provided a clear increase in pressure drop across the filter in the loading of the filter. The best after-filtration materials proved to be quite effective also for fine particles. The best mass removal efficiencies for fine particles around 0.3 mum were over 80% for some filter materials loaded with sanding wood dust.

  13. Screening culture filtrates of fungi for activity against Tylenchulus semipenetrans

    Energy Technology Data Exchange (ETDEWEB)

    Verdejo-Lucas, S.; Viera, A.; Stchigel, A. M.; Sorribas, F. J.

    2009-07-01

    Culture filtrates of 20 fungi isolated from citrus soils were screened for their activity against Tylenchulus semipenetrans in both in vitro and greenhouse tests. The filtrates of Talaromyces cyanescens (isolates 2-4 and 2-5), Paecilomyces lilacinus, Chaetomium robustum, Acremonium strictum, Engyodontium album, Myrothecium verrucaria, Emericella rugulosa, and Tarracomyces gigaspora consistently inhibited the motility of second-stage juveniles at various concentrations of the filtrate. Dose-response models were used to determine the filtrate concentration required to inhibit the motility of 50% of the juveniles (CI50). The culture filtrate of P. lilacinus showed the highest activity with a CI50 value of 58% that differed from that of C. robustum (CI50 = 68%), and A. strictum CI50 = 82%. The culture filtrates of P. lilacinus, E. album, and T. cyanescens 2-5 maintained their activity when autoclaved at 120 degree centigrade for 20 min. The autoclaved filtrate of T. cyanescens 2-4 was more effective at inhibiting juvenile motility (CI50 = 28%) than that of T. cyanescens 2-5 (CI50 = 80%), C. robustum (CI50 = 72 %) and P. lilacinus (CI50 = 72%). The culture filtrate of T. cyanescens 2-4 also inhibited egg hatching. Nematode reproduction on Cleopatra mandarin and Carrizo citrange were respectively reduced by the culture filtrate of P. lilacinus and the autoclaved filtrate of T. cyanescens 2-4. These results support the hypothesis that soil fungi may contribute to regulate nematode densities by the production of secondary metabolites with nematicidal activity. (Author) 30 refs.

  14. Instability Suppression in a Swirl-Stabilized Combustor Using Microjet Air Injection

    KAUST Repository

    LaBry, Zachary

    2010-01-04

    In this study, we examine the effectiveness of microjet air injection as a means of suppressing thermoacoustic instabilities in a swirl-stabilized, lean-premixed propane/air combustor. High-speed stereo PIV measurements, taken to explore the mechanism of combustion instability, reveal that the inner recirculation zone plays a dominant role in the coupling of acoustics and heat release that leads to combustion instability. Six microjet injector configurations were designed to modify the inner and outer recirculation zones with the intent of decoupling the mechanism leading to instability. Microjets that injected air into the inner recirculation zone, swirling in the opposite sense to the primary swirl were effective in suppressing combustion instability, reducing the overall sound pressure level by up to 17 dB within a certain window of operating conditions. Stabilization was achieved near an equivalence ratio of 0.65, corresponding to the region where the combustor transitions from a 40 Hz instability mode to a 110 Hz instability mode. PIV measurements made of the stabilized flow revealed significant modification of the inner recirculation zone and substantial weakening of the outer recirculation zone.

  15. Research of ceramic membrane filtration characteristics in continuous reaction system%连续反应系统中陶瓷膜过滤特性研究

    Institute of Scientific and Technical Information of China (English)

    张凤莉; 孙亚峰; 杨阿三

    2014-01-01

    Ceramic membrane module has high separation efficiency and good stability. In this thesis, we make multiphase reactor and ceramic membrane filtration components a continuous device, in order to realize the solid-liquid separation and continuous operation, we used three phases system including air, water and activated carbon as our study medium, studying its filtration characteristics, investigating the stability of the ceramic mem-brane filter components and membrane filtrating pressure and the effect of circulation pump frequency conversion on the components of ceramic membrane filtration flux. The results showed that the ceramic membrane components can ensure the stability to filter in the longer term;Filtration flux are greatly affected by the filtration pressure pro-portionally, the greater the filtrating pressure, the larger the filtration flux will be; In addition to this, the filtration flux increases with the growth of circulation flow rate.%陶瓷膜组件具有较高的分离效率且稳定性好,本文是将多相反应器与陶瓷膜过滤组件组成连续装置,以期实现液固分离和操作的连续化,以空气-水-活性炭三相为研究介质,对其过滤特性进行研究,结果表明:陶瓷膜组件能够确保在较长时间内过滤的稳定性;过滤通量受过滤压力的影响较大,过滤压力越大过滤通量越大;过滤通量随着循环流量的增大而增大。

  16. A simple high-performance matrix-free biomass molten carbonate fuel cell without CO2 recirculation.

    Science.gov (United States)

    Lan, Rong; Tao, Shanwen

    2016-08-01

    In previous reports, flowing CO2 at the cathode is essential for either conventional molten carbonate fuel cells (MCFCs) based on molten carbonate/LiAlO2 electrolytes or matrix-free MCFCs. For the first time, we demonstrate a high-performance matrix-free MCFC without CO2 recirculation. At 800°C, power densities of 430 and 410 mW/cm(2) are achieved when biomass-bamboo charcoal and wood, respectively-is used as fuel. At 600°C, a stable performance is observed during the measured 90 hours after the initial degradation. In this MCFC, CO2 is produced at the anode when carbon-containing fuels are used. The produced CO2 then dissolves and diffuses to the cathode to react with oxygen in open air, forming the required [Formula: see text] or [Formula: see text] ions for continuous operation. The dissolved [Formula: see text] ions may also take part in the cell reactions. This provides a simple new fuel cell technology to directly convert carbon-containing fuels such as carbon and biomass into electricity with high efficiency.

  17. An Approach to the Prototyping of an Optimized Limited Stroke Actuator to Drive a Low Pressure Exhaust Gas Recirculation Valve

    Directory of Open Access Journals (Sweden)

    Christophe Gutfrind

    2016-05-01

    Full Text Available The purpose of this article is to describe the design of a limited stroke actuator and the corresponding prototype to drive a Low Pressure (LP Exhaust Gas Recirculation (EGR valve for use in Internal Combustion Engines (ICEs. The direct drive actuator topology is an axial flux machine with two air gaps in order to minimize the rotor inertia and a bipolar surface-mounted permanent magnet in order to respect an 80° angular stroke. Firstly, the actuator will be described and optimized under constraints of a 150 ms time response, a 0.363 N·m minimal torque on an angular range from 0° to 80° and prototyping constraints. Secondly, the finite element method (FEM using the FLUX-3D® software (CEDRAT, Meylan, France will be used to check the actuator performances with consideration of the nonlinear effect of the iron material. Thirdly, a prototype will be made and characterized to compare its measurement results with the analytical model and the FEM model results. With these electromechanical behavior measurements, a numerical model is created with Simulink® in order to simulate an EGR system with this direct drive actuator under all operating conditions. Last but not least, the energy consumption of this machine will be estimated to evaluate the efficiency of the proposed EGR electromechanical system.

  18. An Approach to the Prototyping of an Optimized Limited Stroke Actuator to Drive a Low Pressure Exhaust Gas Recirculation Valve.

    Science.gov (United States)

    Gutfrind, Christophe; Dufour, Laurent; Liebart, Vincent; Vannier, Jean-Claude; Vidal, Pierre

    2016-05-20

    The purpose of this article is to describe the design of a limited stroke actuator and the corresponding prototype to drive a Low Pressure (LP) Exhaust Gas Recirculation (EGR) valve for use in Internal Combustion Engines (ICEs). The direct drive actuator topology is an axial flux machine with two air gaps in order to minimize the rotor inertia and a bipolar surface-mounted permanent magnet in order to respect an 80° angular stroke. Firstly, the actuator will be described and optimized under constraints of a 150 ms time response, a 0.363 N·m minimal torque on an angular range from 0° to 80° and prototyping constraints. Secondly, the finite element method (FEM) using the FLUX-3D(®) software (CEDRAT, Meylan, France) will be used to check the actuator performances with consideration of the nonlinear effect of the iron material. Thirdly, a prototype will be made and characterized to compare its measurement results with the analytical model and the FEM model results. With these electromechanical behavior measurements, a numerical model is created with Simulink(®) in order to simulate an EGR system with this direct drive actuator under all operating conditions. Last but not least, the energy consumption of this machine will be estimated to evaluate the efficiency of the proposed EGR electromechanical system.

  19. Fast spatially resolved exhaust gas recirculation (EGR) distribution measurements in an internal combustion engine using absorption spectroscopy.

    Science.gov (United States)

    Yoo, Jihyung; Prikhodko, Vitaly; Parks, James E; Perfetto, Anthony; Geckler, Sam; Partridge, William P

    2015-09-01

    Exhaust gas recirculation (EGR) in internal combustion engines is an effective method of reducing NOx emissions while improving efficiency. However, insufficient mixing between fresh air and exhaust gas can lead to cycle-to-cycle and cylinder-to-cylinder non-uniform charge gas mixtures of a multi-cylinder engine, which can in turn reduce engine performance and efficiency. A sensor packaged into a compact probe was designed, built and applied to measure spatiotemporal EGR distributions in the intake manifold of an operating engine. The probe promotes the development of more efficient and higher-performance engines by resolving high-speed in situ CO2 concentration at various locations in the intake manifold. The study employed mid-infrared light sources tuned to an absorption band of CO2 near 4.3 μm, an industry standard species for determining EGR fraction. The calibrated probe was used to map spatial EGR distributions in an intake manifold with high accuracy and monitor cycle-resolved cylinder-specific EGR fluctuations at a rate of up to 1 kHz.

  20. Hydraulic study of parallel channels coupled to recirculation loops; Estudio hidraulico de canales paralelos acoplados a lazos de recirculacion

    Energy Technology Data Exchange (ETDEWEB)

    Campos G, R. M.; Cecenas F, M. [Instituto de Investigaciones Electricas, Av. Reforma 113, Col. Palmira, 62490 Cuernavaca, Morelos (Mexico)], e-mail: rmcampos@iie.org.mx

    2009-10-15

    In this work is integrated a model of recirculation loops that allows to characterize each loop for separate and with which is possible to analyze events as shot of recirculation bombs or its transfer of high to low speed. The recirculation pattern is integrated to a model of 36 channels in parallel that represents the core of a BWR. Because the core reactor is conformed by fuel assemblies physically prepared in a parallel arrangement, it is natural to obtain a parallel application of complete pattern, where are have 36 channels tasks more other two tasks that calculates recirculation and punctual kinetics, respectively. As initial test of system, which even it is found in development, was analyzed a discharge of both recirculation pumps. In this test transitory it is only verified the hydraulic behavior, the power is imposed artificially as frontier condition that is function of flow in the calculated core by the recirculation pattern. The pattern of thermal hydraulics channel and the recirculation loops are programmed in language C, the neutronic pattern is programmed in Fortran 77. For the simulations was used a work station Alpha Station DS20E with operative system Unix and the communication system Parallel Virtual Machine, that allows to a heterogeneous collection of computers in net to work like a virtual computer in parallel. (Author)

  1. Simultaneous water desalination and electricity generation in a microbial desalination cell with electrolyte recirculation for pH control

    KAUST Repository

    Qu, Youpeng

    2012-02-01

    A recirculation microbial desalination cell (rMDC) was designed and operated to allow recirculation of solutions between the anode and cathode chambers. This recirculation avoided pH imbalances that could inhibit bacterial metabolism. The maximum power density was 931±29mW/m 2 with a 50mM phosphate buffer solution (PBS) and 776±30mW/m 2 with 25mM PBS. These power densities were higher than those obtained without recirculation of 698±10mW/m 2 (50mM PBS) and 508±11mW/m 2 (25mM PBS). The salt solution (20g/L NaCl) was reduced in salinity by 34±1% (50mM) and 37±2% (25mM) with recirculation (rMDC), and by 39±1% (50mM) and 25±3% (25mM) without recirculation (MDC). These results show that electrolyte recirculation using an rMDC is an effective method to increase power and achieve efficient desalination by eliminating pH imbalances. © 2011 Elsevier Ltd.

  2. Transpulmonary passage of venous air emboli

    Science.gov (United States)

    Butler, B. D.; Hills, B. A.

    1985-01-01

    Twenty-seven paralyzed anesthetized dogs were embolized with venous air to determine the effectiveness of the pulmonary vasculature for bubble filtration or trapping. Air doses ranged from 0.05 to 0.40 ml/kg min in 0.05-ml increments with ultrasonic Doppler monitors placed over arterial vessels to detect any microbubbles that crossed the lungs. Pulmonary vascular filtration of the venous air infusions was complete for the lower air doses ranging from 0.05 to 0.30 ml/kg min. When the air doses were increased to 0.35 ml/kg min, the filtration threshold was exceeded with arterial spillover of bubbles occurring in 50 percent of the animals and reaching 71 percent for 0.40 ml/kg min. Significant elevations were observed in pulmonary arterial pressure and pulmonary vascular resistance. Systemic blood pressure and cardiac output decreased, whereas left ventricular end-diastolic pressure remained unchanged. The results indicate that the filtration of venous bubbles by the pulmonary vasculature was complete when the air infusion rates were kept below a threshold value of 0.30 ml/kg min.

  3. Sorghum genome sequencing by methylation filtration.

    Directory of Open Access Journals (Sweden)

    Joseph A Bedell

    2005-01-01

    Full Text Available Sorghum bicolor is a close relative of maize and is a staple crop in Africa and much of the developing world because of its superior tolerance of arid growth conditions. We have generated sequence from the hypomethylated portion of the sorghum genome by applying methylation filtration (MF technology. The evidence suggests that 96% of the genes have been sequence tagged, with an average coverage of 65% across their length. Remarkably, this level of gene discovery was accomplished after generating a raw coverage of less than 300 megabases of the 735-megabase genome. MF preferentially captures exons and introns, promoters, microRNAs, and simple sequence repeats, and minimizes interspersed repeats, thus providing a robust view of the functional parts of the genome. The sorghum MF sequence set is beneficial to research on sorghum and is also a powerful resource for comparative genomics among the grasses and across the entire plant kingdom. Thousands of hypothetical gene predictions in rice and Arabidopsis are supported by the sorghum dataset, and genomic similarities highlight evolutionarily conserved regions that will lead to a better understanding of rice and Arabidopsis.

  4. Capturing phosphates with iron enhanced sand filtration.

    Science.gov (United States)

    Erickson, Andrew J; Gulliver, John S; Weiss, Peter T

    2012-06-01

    Most treatment practices for urban runoff capture pollutants such as phosphorus by either settling or filtration while dissolved phosphorus, typically as phosphates, is untreated. Dissolved phosphorus, however, represents an average 45% of total phosphorus in stormwater runoff and can be more than 95%. In this study, a new stormwater treatment technology to capture phosphate, called the Minnesota Filter, is introduced. The filter comprises iron filings mixed with sand and is tested for phosphate removal from synthetic stormwater. Results indicate that sand mixed with 5% iron filings captures an average of 88% phosphate for at least 200 m of treated depth, which is significantly greater than a sand filter without iron filings. Neither incorporation of iron filings into a sand filter nor capture of phosphates onto iron filings in column experiments had a significant effect on the hydraulic conductivity of the filter at mixtures of 5% or less iron by weight. Field applications with up to 10.7% iron were operated over 1 year without detrimental effects upon hydraulic conductivity. A model is applied and fit to column studies to predict the field performance of iron-enhanced sand filters. The model predictions are verified through the predicted performance of the filters in removing phosphates in field applications. Practical applications of the technology, both existing and proposed, are presented so stormwater managers can begin implementation.

  5. Crosslinked polytriazole membranes for organophilic filtration

    KAUST Repository

    Chisca, Stefan

    2016-12-30

    We report the preparation of crosslinked membranes for organophilic filtration, by reacting a new polytriazole with free OH groups, using non-toxic poly (ethylene glycol) diglycidyl ether (PEGDE). The OH-functionalized polymer was obtained by converting the oxadiazole to triazole rings with high yield (98%). The maximum degree of crosslinking is achieved after 6 h of reaction. The crosslinked polytriazole membranes are stable in a wide range of organic solvents and show high creep recovery, indicating the robustness of crosslinked membranes. The influence of different casting solutions and different crosslinking time on the membrane morphology and membrane performance was investigated. The membranes performance was studied in dimethylformamide (DMF) and (tetrahydrofuran) THF. We achieved a permeance for THF of 49 L m−2 h−1 bar−1 for membranes with molecular weight cut off (MWCO) of 7 kg mol−1 and a permeance for THF of 17.5 L m−2 h−1 bar−1 for membranes with MWCO of 3 kg mol−1. Our data indicate that by using the new polytriazole is possible to adjust the pore dimensions of the membranes to have a MWCO, which covers ultra- and nanofiltration range.

  6. Estimating Glomerular Filtration Rate in Older People

    Directory of Open Access Journals (Sweden)

    Sabrina Garasto

    2014-01-01

    Full Text Available We aimed at reviewing age-related changes in kidney structure and function, methods for estimating kidney function, and impact of reduced kidney function on geriatric outcomes, as well as the reliability and applicability of equations for estimating glomerular filtration rate (eGFR in older patients. CKD is associated with different comorbidities and adverse outcomes such as disability and premature death in older populations. Creatinine clearance and other methods for estimating kidney function are not easy to apply in older subjects. Thus, an accurate and reliable method for calculating eGFR would be highly desirable for early detection and management of CKD in this vulnerable population. Equations based on serum creatinine, age, race, and gender have been widely used. However, these equations have their own limitations, and no equation seems better than the other ones in older people. New equations specifically developed for use in older populations, especially those based on serum cystatin C, hold promises. However, further studies are needed to definitely accept them as the reference method to estimate kidney function in older patients in the clinical setting.

  7. Pulmonary interstitial compliance and microvascular filtration coefficient.

    Science.gov (United States)

    Goldberg, H S

    1980-08-01

    Static and dynamic properties governing the fluid movement into the pulmonary interstitium were examined in isolated canine lobes. The system was driven by altering intravascular presure (Piv) when the lobe was isogravimetric (change in weight (W) = 0) and allowing the lobe to become isogravimetric again. By making use of an analogy to charging a capacitor across a resistor, calculation of the filtration coefficient for transvascular fluid movement (KF) and determination of the pressure-volume relationship of the pulmonary interstitial space (Pis-Vis), with a minimum of untested assumptions, was possible. KF was found to be the same for fluid moving out of or into the intravascular space, and when the relationship between Piv and alveolar pressure (PAlv) was constant, KF was independent of transpulmonary pressure (PL). When PAlv exceeded Piv, changes in Piv did not influence KF, suggesting no significant change in either surface area available for fluid transudation or vascular permeability. The Pis-Vis curve for increasing values of Vis and Pis is best described by an exponential relationhip and is independent of PL. However, the Pis-Vis curve with decreasing values of Vis and Pis is dependent on PL.

  8. Sorghum genome sequencing by methylation filtration.

    Science.gov (United States)

    Bedell, Joseph A; Budiman, Muhammad A; Nunberg, Andrew; Citek, Robert W; Robbins, Dan; Jones, Joshua; Flick, Elizabeth; Rholfing, Theresa; Fries, Jason; Bradford, Kourtney; McMenamy, Jennifer; Smith, Michael; Holeman, Heather; Roe, Bruce A; Wiley, Graham; Korf, Ian F; Rabinowicz, Pablo D; Lakey, Nathan; McCombie, W Richard; Jeddeloh, Jeffrey A; Martienssen, Robert A

    2005-01-01

    Sorghum bicolor is a close relative of maize and is a staple crop in Africa and much of the developing world because of its superior tolerance of arid growth conditions. We have generated sequence from the hypomethylated portion of the sorghum genome by applying methylation filtration (MF) technology. The evidence suggests that 96% of the genes have been sequence tagged, with an average coverage of 65% across their length. Remarkably, this level of gene discovery was accomplished after generating a raw coverage of less than 300 megabases of the 735-megabase genome. MF preferentially captures exons and introns, promoters, microRNAs, and simple sequence repeats, and minimizes interspersed repeats, thus providing a robust view of the functional parts of the genome. The sorghum MF sequence set is beneficial to research on sorghum and is also a powerful resource for comparative genomics among the grasses and across the entire plant kingdom. Thousands of hypothetical gene predictions in rice and Arabidopsis are supported by the sorghum dataset, and genomic similarities highlight evolutionarily conserved regions that will lead to a better understanding of rice and Arabidopsis.

  9. Filtration application from recycled expanded polystyrene.

    Science.gov (United States)

    Shin, C

    2006-10-01

    Water-in-oil emulsion with drop size less than 100 mum is difficult to separate. Coalescence filtration is economical and effective for separation of secondary dispersions. Coalescence performance depends on flow rate, bed depth, fiber surface properties, and drop size. The amount of surface area of the fibers directly affects the efficiency. A new recycling method was investigated in the previous work in which polystyrene (PS) sub-mum fibers were electro-spun from recycled expanded polystyrene (EPS). These fibers are mixed with micro glass fibers to modify the glass fiber filter media. The filter media are tested in the separation of water droplets from an emulsion of water droplets in oil. The experimental results in this work show that adding nanofibers to conventional micron sized fibrous filter media improves the separation efficiency of the filter media but also increases the pressure drop. An optimum in the performance occurs (significant increase in efficiency with minimal increase in pressure drop) with the addition of about 4% by mass of 500 nm diameter PS nanofibers to glass fibers for the filters.

  10. Efficient filtration system for paraffin-catalyst slurry separation

    Directory of Open Access Journals (Sweden)

    Khodagholi Mohammad Ali

    2013-01-01

    Full Text Available The filtration efficiency for separating liquid paraffin (or water from a slurry consisting of 25 weight% spherical alumina in a Slurry Bubble Column Reactor (SBCR comprised of a cylindrical tube of 10 cm diameter and 150 cm length was studied. Various differential pressures (ΔP were applied to two separate tubular sintered metal stainless steel filter elements with nominal pore size of 4 and 16μm. The experimental results disclosed that the rate of filtrations increased on applying higher differential pressure to the filter element. Albeit this phenomenon is limited to moderate ΔPs and for ΔP more than 1 bar is neither harmful nor helpful. The highest filtration rates at ΔPs higher than 1 bar were 170 and 248 ml/minute for 4 and 16μm respectively. Using water as the liquid in slurry the rate of filtration enhanced to 4 folds, and this issue reveals impact of viscosity on filtration efficiency clearly. In all situations, the total amount of particles present in the filtrate part never exceeded a few parts per million (ppm. The statistical analysis of the SEM image of the filtrate indicated that by applying higher pressure difference to the filter element the frequency percent of larger particle size increases. The operation of filter cake removing was performed with back flashing of 300 ml of clean liquid with pressures of 3-5 bar of N2 gas.

  11. THE STUDY OF THE FILTRATION EFFICIENCY OF FILTER MATERIAL

    Institute of Scientific and Technical Information of China (English)

    Jia Ruiqing; Wang Luping; Wu Xueping

    2000-01-01

    In this paper, the course of the filtration is analyzed.In order to study the filtration efficiency of the filter material, the computer program was edited.According to the results of the computer program, some important parameters of the filter material are discussed.It shows that the filtration efficiency is closely related to the diameter (d) and the size (b).In addition, by using these results and the computer program, we can analysis the relationship between the fiber structure and filter properties quantitatively.

  12. Additive Difference Schemes for Filtration Problems in Multilayer Systems

    CERN Document Server

    Ayrjan, E A; Pavlush, M; Fedorov, A V

    2000-01-01

    In the present paper difference schemes for solution of the plane filtration problem in multilayer systems are analyzed within the framework of difference schemes general theory. Attention is paid to splitting the schemes on physical processes of filtration along water-carring layers and vertical motion between layers. Some absolutely stable additive difference schemes are obtained the realization of which needs no software modification. Parallel algorithm connected with the solving of the filtration problem in every water-carring layer on a single processor is constructed. Program realization on the multi-processor system SPP2000 at JINR is discussed.

  13. Flame dynamics of a meso-scale heat recirculating combustor

    Energy Technology Data Exchange (ETDEWEB)

    Vijayan, V.; Gupta, A.K. [Department of Mechanical Engineering, University of Maryland, College Park, MD 20742 (United States)

    2010-12-15

    The dynamics of premixed propane-air flame in a meso-scale ceramic combustor has been examined here. The flame characteristics in the combustor were examined by measuring the acoustic emissions and preheat temperatures together with high-speed cinematography. For the small-scale combustor, the volume to surface area ratio is small and hence the walls have significant effect on the global flame structure, flame location and flame dynamics. In addition to the flame-wall thermal coupling there is a coupling between flame and acoustics in the case of confined flames. Flame-wall thermal interactions lead to low frequency flame fluctuations ({proportional_to}100 Hz) depending upon the thermal response of the wall. However, the flame-acoustic interactions can result in a wide range of flame fluctuations ranging from few hundred Hz to few kHz. Wall temperature distribution is one of the factors that control the amount of reactant preheating which in turn effects the location of flame stabilization. Acoustic emission signals and high-speed flame imaging confirmed that for the present case flame-acoustic interactions have more significant effect on flame dynamics. Based on the acoustic emissions, five different flame regimes have been identified; whistling/harmonic mode, rich instability mode, lean instability mode, silent mode and pulsating flame mode. (author)

  14. Estimates of associated outdoor particulate matter health risk and costs reductions from alternative building, ventilation and filtration scenarios.

    Science.gov (United States)

    Sultan, Zuraimi M

    2007-05-01

    Although many studies have reported calculations of outdoor particulate matter (PM) associated externalities using ambient data, there is little information on the role buildings, their ventilation and filtration play. This study provides the framework to evaluate the health risk and cost reduction of building, ventilation and filtration strategies from outdoor PM pollution on a nationwide level and applied it to a case study in Singapore. Combining Indoor Air Quality (IAQ) and time weighted exposure models, with established concentration-response functions and monetary valuation methods, mortality and morbidity effects of outdoor PM on the population of Singapore under different building, ventilation and filtration strategies were estimated. Different interventions were made to compare the effects from the current building conditions. The findings demonstrate that building protection effect reduced approximately half the attributable health cases amounting to US$17.7 billion due to PM pollution when compared to levels computed using outdoor data alone. For residential buildings, nationwide adoption of natural ventilation from current state is associated with 28% higher cases of mortality and 13 to 38% higher cases for different morbidities, amounting to US$6.7 billion. The incurred cost is negligible compared to energy costs of air-conditioning. However, nationwide adoption of closed residence and air-conditioning are associated with outcomes including fewer mortality (10 and 6% respectively), fewer morbidities (8 and 4% respectively) and economic savings of US$1.5 and 0.9 billion respectively. The related savings were about a factor of 9 the energy cost for air-conditioning. Nationwide adoption of mechanical ventilation and filtration from current natural ventilation in schools is associated with fewer asthma hospital admissions and exacerbations; although the economic impact is not substantial. Enhanced workplace filtration reduces the mortality and morbidity

  15. Design of multifamily solar domestic hot water systems using recirculating distribution

    Energy Technology Data Exchange (ETDEWEB)

    Wedekind, D.R.

    1982-01-01

    This paper describes a study designed to quantify the effect of daily domestic hot water loads and system design on the performance of solar domestic hot water systems employing a recirculating distribution system. A solar domestic hot water system judged representative of the systems funded by the HUD Solar Demonstration Program, along with a modification to this system, was modeled using the TRNSYS simulation computer program. Results of simulations over a representative climatic period show that daily domestic hot water usage significantly affects solar system performance. Notable improvement in system performance can be obtained by the use of a recirculation return to solar storage system configuration within a specific range of daily domestic hot water loads. An optimum system was developed from parametric variations of system design and modeled on an annual basis. Comparison is made to modeled system performance of the original design.

  16. Continuous hydrothermal co-liquefaction of aspen wood and glycerol with water phase recirculation

    DEFF Research Database (Denmark)

    Pedersen, Thomas H.; Grigoras, Ionela F.; Hoffmann, Julia

    2016-01-01

    heating value of 34.3 MJ/kg. The volatile fraction of the biocrude consisted mostly of compounds having number of carbon atoms in the C6–C12 range similar to gasoline. In terms of process feasibility, it was revealed that total organic carbon (TOC) and ash significantly accumulated in the water phase when...... such is recirculated for the proceeding batch. After four batches the TOC and the ash mass fraction of the water phase were 136.2 [g/L] and 12.6 [%], respectively. Water phase recirculation showed a slight increase in the biocrude quality in terms on an effective hydrogen-to-carbon ratio, but it showed no effects...

  17. Conservation principles suspended solids distribution modeling to support ATS introduction on a recirculating WWTP

    DEFF Research Database (Denmark)

    Gernaey, Krist Victor Bernard; Nielsen, M.K.; Thornberg, D.;

    2004-01-01

    the potential benefit of ATS implementation on a full-scale recirculating WWTP. A reduction of the maximum SS peak load to the secondary clarifiers with 24.9% was obtained with ATS, whereas the cumulative SS load to the clarifiers is foreseen to be reduced with 22.5% for short rain events (4 hours duration......) and with 16.6% for long rain events (24 hours duration). The SS distribution model is a useful tool for off-line studies of the potential benefits to be obtained by introducing ATS on a recirculating WWTP. Finally, the successful operation of the ATS process on the full-scale plant is illustrated with data....

  18. Daily micro particle distribution of an experimental recirculating aquaculture system – A case study

    DEFF Research Database (Denmark)

    Fernandes, Paulo; Pedersen, Lars-Flemming; Pedersen, Per Bovbjerg

    2014-01-01

    The particle size distribution (PSD) in a recirculating aquaculture system (RAS) was investigated duringa 24-h cycle. PSD was analyzed in water sampled at several locations in a recirculation loop containing a60-m drum filter, a submerged fixed-bed biofilter and a trickling filter.In relation...... to total counts, the system was dominated by micro-particles with particles smaller than20 m comprising >94% of the distribution in all samples. However, the system presented a substantialvolumetric influence of larger particles, reflected by a PSD derivate ˇ-value of 3.40 ± 0.18. Overall ˇ......-valuesthroughout the compartments (p = 0.584) and experimental period (p = 0.217) were not significantlydifferent, although specific components seemed to marginally affect the PSD.A high internal water turnover rate (one system passage every 50 min) promoted the rapid removalof large particles from the system. Permanent volumetric...

  19. Peripheral regulatory T lymphocytes recirculating to the thymus suppress the development of their precursors.

    Science.gov (United States)

    Thiault, Nicolas; Darrigues, Julie; Adoue, Véronique; Gros, Marine; Binet, Bénédicte; Perals, Corine; Leobon, Bertrand; Fazilleau, Nicolas; Joffre, Olivier P; Robey, Ellen A; van Meerwijk, Joost P M; Romagnoli, Paola

    2015-06-01

    Most T lymphocytes, including regulatory T cells (Treg cells), differentiate in the thymus. The age-dependent involution of this organ leads to decreasing production of T cells. Here we found that the output of new Treg cells from the thymus decreased substantially more than that of conventional T cells. Peripheral mouse and human Treg cells recirculated back to the thymus, where they constituted a large proportion of the pool of Treg cells and displayed an activated and differentiated phenotype. In the thymus, the recirculating cells exerted their regulatory function by inhibiting interleukin 2 (IL-2)-dependent de novo differentiation of Treg cells. Thus, Treg cell development is controlled by a negative feedback loop in which mature progeny cells return to the thymus and restrain development of precursors of Treg cells.

  20. Conservation principles suspended solids distribution modeling to support ATS introduction on a recirculating WWTP

    DEFF Research Database (Denmark)

    Gernaey, Krist Victor Bernard; Nielsen, M.K.; Thornberg, D.

    2004-01-01

    A model for the description of the SS distribution in a full-scale recirculating activated sludge WWTP was developed. The model, based on conservation principles, uses on-line plant data as model inputs, and provides a prediction of the SS load in the inlet to the secondary clarifiers and the SS...... distribution in the WWTP as outputs. The calibrated model produces excellent predictions of the SS load to the secondary clarifiers, an essential variable for the operation of the aeration tank settling (ATS) process. A case study illustrated how the calibrated SS distribution model can be used to evaluate...... the potential benefit of ATS implementation on a full-scale recirculating WWTP. A reduction of the maximum SS peak load to the secondary clarifiers with 24.9% was obtained with ATS, whereas the cumulative SS load to the clarifiers is foreseen to be reduced with 22.5% for short rain events (4 hours duration...