High flow ceramic pot filters.

Science.gov (United States)

van Halem, D; van der Laan, H; Soppe, A I A; Heijman, S G J

2017-11-01

Ceramic pot filters are considered safe, robust and appropriate technologies, but there is a general consensus that water revenues are limited due to clogging of the ceramic element. The objective of this study was to investigate the potential of high flow ceramic pot filters to produce more water without sacrificing their microbial removal efficacy. High flow pot filters, produced by increasing the rice husk content, had a higher initial flow rate (6-19 L h -1 ), but initial LRVs for E. coli of high flow filters was slightly lower than for regular ceramic pot filters. This disadvantage was, however, only temporarily as the clogging in high flow filters had a positive effect on the LRV for E. coli (from below 1 to 2-3 after clogging). Therefore, it can be carefully concluded that regular ceramic pot filters perform better initially, but after clogging, the high flow filters have a higher flow rate as well as a higher LRV for E. coli. To improve the initial performance of new high flow filters, it is recommended to further utilize residence time of the water in the receptacle, since additional E. coli inactivation was observed during overnight storage. Although a relationship was observed between flow rate and LRV of MS2 bacteriophages, both regular and high flow filters were unable to reach over 2 LRV. Copyright © 2017 Elsevier Ltd. All rights reserved.

Controlling flow conditions of test filters in iodine filters

International Nuclear Information System (INIS)

Holmberg, R.; Laine, J.

1979-03-01

Several different iodine filter and test filter designs and experience gained from their operation are presented. For the flow experiments, an iodine filter system equipped with flow regulating and measuring devices was built. In the experiments the influence of the packing method of the iodine sorption material and the influence of the flow regulating and measuring divices upon the flow conditions in the test filters was studied. On the basis of the experiments it has been shown that the flows through the test filters always can be adjusted to a correct value if there only is a high enough pressure difference available across the test filter ducting. As a result of the research, several different methods are presented with which the flows through the test filters in both operating and future iodine sorption system can easily be measured and adjusted to their correct values. (author)

Hydrodynamic calculation of a filter washing in liquids type used in containment venting systems; Calculo hidrodinamico de un filtro tipo lavado en liquidos usados en los sistemas de venteo de la contencion

Energy Technology Data Exchange (ETDEWEB)

Reyes G, A. A.; Sainz M, E.; Ortiz V, J., E-mail: alejandroantonioreyess@gmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

2015-09-15

From the nuclear accident of Chernobyl, the European nuclear power plants have chosen to install filters on the venting pipes of the containment, whose function is to help to mitigate the consequences of a severe accident, by controlled depressurization of the containment passively through a filtered venting of the containment system. These systems are designed to relieve the internal pressure of the containment by means of the deliberate opening of pressure relief devices, either a valve or rupture disc during a severe accident and be channeled to the filter unit. In this paper the hydraulic response of a filter system of gases washing by liquid is evaluated, due to this information is necessary to estimate the effect that has the pressure increase of the contention on the discharge capacity of the venting pipes. By simulation of computational of fluid dynamics with the programs: CAELINUX-2014 and OpenFOAM, the hydrodynamic characteristics of the Multi Venturi System for gases washing from the containment, which could be included in the general model of the venting pipe, were obtained. Representative models of the Venturi tubes of each concentric area that forming the washing system were generated; and using parametric calculations the average mass flow rate established through each venturi, depending on its size and depth in which it is located inside the tank was estimated. Also, the pressure and mass flow rate required to activate each concentric area depending on the pressure and mass load from the containment were calculated, to estimate the maximum flow that is established through the filter. Finally, the velocity profiles and the characteristic pressure at which each area operates as well as the pressure drop of local and global discharge also were calculated. (Author)

Removal of chloride from fly ash produced in hazardous waste incineration by leaching and displacement washing in a vertical filter press.

Science.gov (United States)

Kinnarinen, Teemu; Huhtanen, Mikko; Penttilä, Mika; Häkkinen, Antti

2013-02-01

Fly ash is generated in large quantities by waste incineration processes. Chloride is commonly present in the fly ash produced by the incineration of hazardous materials, such as polyvinylchloride plastic. Major difficulties related to the disposal and handling of fly ash include the high concentration of easily leachable chlorides, heavy metals and toxic compounds. In order to avoid adverse environmental effects from the disposal of fly ash, the content of soluble chlorides must be reduced. One of the most effective options for chloride removal is leaching and displacement washing in a filter press. The primary aim of this study was to obtain efficient removal of chloride from fly ash by utilizing a leaching and displacement washing process, carried out in a filter press. The secondary objective was to obtain high filtration capacities and low filter cake moisture contents. The slurry was prepared by mixing fly ash with water at an ash:water ratio of 1:2 and filtered to separate the solids from the liquid. After solid-liquid separation, most of the dissolved residual chloride was removed from the filter cake by washing the cake with fresh water in the second stage of separation. It was possible to remove up to 98% of the total chloride and to obtain sufficient filtration capacities. The residual moisture content of the filter cakes varied from 22 to 35 wt%, which meant that the cakes could be disposed of in landfill, or possibly utilized as a construction material.

High flow ceramic pot filters

OpenAIRE

van Halem, D.; van der Laan, H.; Soppe, A. I.A.; Heijman, S.G.J.

2017-01-01

Ceramic pot filters are considered safe, robust and appropriate technologies, but there is a general consensus that water revenues are limited due to clogging of the ceramic element. The objective of this study was to investigate the potential of high flow ceramic pot filters to produce more water without sacrificing their microbial removal efficacy. High flow pot filters, produced by increasing the rice husk content, had a higher initial flow rate (6–19 L h−1), but initial LRVs for E. coli o...

Effect of Disinfectants on Preventing the Cross-Contamination of Pathogens in Fresh Produce Washing Water

NARCIS (Netherlands)

Banach, J.L.; Sampers, I.; Haute, van S.; Fels, van der H.J.

2015-01-01

The potential cross-contamination of pathogens between clean and contaminated produce in the washing tank is highly dependent on the water quality. Process wash water disinfectants are applied to maintain the water quality during processing. The review examines the efficacy of process wash water

Cross contamination of Escherichia coli O157:H7 between lettuce and wash water during home-scale washing.

Science.gov (United States)

Jensen, Dane A; Friedrich, Loretta M; Harris, Linda J; Danyluk, Michelle D; Schaffner, Donald W

2015-04-01

Lettuce and leafy greens have been implicated in multiple foodborne disease outbreaks. This study quantifies cross contamination between lettuce pieces in a small-scale home environment. A five-strain cocktail of relevant Escherichia coli O157:H7 strains was used. Bacterial transfer between single inoculated lettuce leaf pieces to 10 non-inoculated lettuce leaf pieces that were washed in a stainless steel bowl of water for 30 s, 1 min, 2 min, and 5 min was quantified. Regardless of washing time, the wash water became contaminated with 90-99% of bacteria originally present on the inoculated lettuce leaf piece. The E. coli O157:H7 concentration on initially inoculated leaf pieces was reduced ∼ 2 log CFU. Each initially uncontaminated lettuce leaf piece had ∼ 1% of the E. coli O157:H7 from the inoculated lettuce piece transferred to it after washing, with more transfer occurring during the shortest (30 s) and longest (5 min) wash times. In all cases the log percent transfer rates were essentially normally distributed. In all scenarios, most of the E. coli O157:H7 (90-99%) transferred from the inoculated lettuce pieces to the wash water. Washing with plain tap water reduces levels of E. coli O157:H7 on the inoculated lettuce leaf pieces, but also spreads contamination to previously uncontaminated leaf pieces. Copyright © 2014 Elsevier Ltd. All rights reserved.

Velocity measurements in a rigid ceramic filter in a parallel-flow arrangement

International Nuclear Information System (INIS)

Al-Hajeri, M.H.; Aroussi, A.; Witry, A.

2002-01-01

Rigid ceramic filters have been developed for cleaning the hot combustion gas streams upstream of the turbine in a combined cycle power plant. To obtain continues operation a periodic cleaning is necessary and the cleaning efficiency depends on the distribution of the filtration cake. Consequently uniform particle deposition on the filter element surface is desired. The flow around three filter elements in cross flow is investigated computationally using the commercial code FLUENT. Three filter elements are placed in a two-dimensional rectangle duct with fixed face velocity and varying the velocity ratio between the approach and face velocity. Particle trajectories are obtained for a number of particle diameters and different inlet (approach) velocity to face filtration velocity ratios to investigate the behavior of particles around the filter element. (author)

Hanford underground storage tank waste filtration process evaluation

International Nuclear Information System (INIS)

Walker, B.W.; McCabe, D.J.

1997-01-01

The purpose of this filter study was to evaluate cross-flow filtration as effective solid-liquid separation technology for treating Hanford wastes, outline operating conditions for equipment, examine the expected filter flow rates, and determine proper cleaning. Two Hanford waste processing applications have been identified as candidates for the use of cross-flow filtration. The first of the Hanford applications involves filtration of the decanted supernate from sludge leaching and washing operations. This process involves the concentration and removal of dilute (0.05 wt percent) fines from the bulk of the supernate. The second application involves filtration to wash and concentrate the sludge during out-of-tank processing. This process employs a relatively concentrated (8 wt percent) solids feed stream. Filter studies were conducted with simulants to evaluate whether 0.5 micron cross-flow sintered metal Mott filters and 0.1 micron cross-flow Graver filters can perform solid-liquid separation of the solid/liquid waste streams effectively. In cross-flow filtration the fluid to be filtered flows in parallel to the membrane surface and generates shearing forces and/or turbulence across the filter medium. This shearing influences formation of filter cake stabilizing the filtrate flow rate

EFRT M-12 Issue Resolution: Solids Washing

Energy Technology Data Exchange (ETDEWEB)

Baldwin, David L.; Schonewill, Philip P.; Toth, James J.; Huckaby, James L.; Eslinger, Paul W.; Hanson, Brady D.; Kurath, Dean E.; Minette, Michael J.

2009-08-14

Pacific Northwest National Laboratory (PNNL) has been tasked by Bechtel National Inc. (BNI) on the River Protection Project-Hanford Tank Waste Treatment and Immobilization Plant (RPP-WTP) project to perform research and development activities to resolve technical issues identified for the Pretreatment Facility (PTF). The Pretreatment Engineering Platform (PEP) was designed, constructed, and operated as part of a plan to respond to issue M12, “Undemonstrated Leaching Processes.” The PEP is a 1/4.5-scale test platform designed to simulate the WTP pretreatment caustic leaching, oxidative leaching, ultrafiltration solids concentration, and slurry washing processes. The PEP replicates the WTP leaching processes using prototypic equipment and control strategies. Two operating scenarios were evaluated for the ultrafiltration process (UFP) and leaching operations. The first scenario has caustic leaching performed in the UFP-VSL-T01A/B ultrafiltration feed vessels, identified as Integrated Test A. The second scenario has caustic leaching conducted in the UFP-VSL-T02A ultrafiltration feed preparation vessel, identified as Integrated Test B. Washing operations in PEP Integrated Tests A and B were conducted successfully as per the approved run sheets. However, various minor instrumental problems occurred, and some of the process conditions specified in the run sheet were not met during the wash operations, such as filter-loop flow-rate targets not being met. Five analytes were selected based on full solubility and monitored in the post-caustic-leach wash as successful indicators of washing efficiency. These were aluminum, sulfate, nitrate, nitrite, and free hydroxide. Other analytes, including sodium, oxalate, phosphate, and total dissolved solids, showed indications of changing solubility; therefore, they were unsuitable for monitoring washing efficiency. In the post-oxidative-leach wash, two analytes with full solubility were selected as suitable indicators of washing

Effect of Disinfectants on Preventing the Cross-Contamination of Pathogens in Fresh Produce Washing Water

Directory of Open Access Journals (Sweden)

Jennifer L. Banach

2015-07-01

Full Text Available The potential cross-contamination of pathogens between clean and contaminated produce in the washing tank is highly dependent on the water quality. Process wash water disinfectants are applied to maintain the water quality during processing. The review examines the efficacy of process wash water disinfectants during produce processing with the aim to prevent cross-contamination of pathogens. Process wash water disinfection requires short contact times so microorganisms are rapidly inactivated. Free chlorine, chlorine dioxide, ozone, and peracetic acid were considered suitable disinfectants. A disinfectant’s reactivity with the organic matter will determine the disinfectant residual, which is of paramount importance for microbial inactivation and should be monitored in situ. Furthermore, the chemical and worker safety, and the legislative framework will determine the suitability of a disinfection technique. Current research often focuses on produce decontamination and to a lesser extent on preventing cross-contamination. Further research on a sanitizer’s efficacy in the washing water is recommended at the laboratory scale, in particular with experimental designs reflecting industrial conditions. Validation on the industrial scale is warranted to better understand the overall effects of a sanitizer.

Effect of Disinfectants on Preventing the Cross-Contamination of Pathogens in Fresh Produce Washing Water

Science.gov (United States)

Banach, Jennifer L.; Sampers, Imca; Van Haute, Sam; van der Fels-Klerx, H.J. (Ine)

2015-01-01

The potential cross-contamination of pathogens between clean and contaminated produce in the washing tank is highly dependent on the water quality. Process wash water disinfectants are applied to maintain the water quality during processing. The review examines the efficacy of process wash water disinfectants during produce processing with the aim to prevent cross-contamination of pathogens. Process wash water disinfection requires short contact times so microorganisms are rapidly inactivated. Free chlorine, chlorine dioxide, ozone, and peracetic acid were considered suitable disinfectants. A disinfectant’s reactivity with the organic matter will determine the disinfectant residual, which is of paramount importance for microbial inactivation and should be monitored in situ. Furthermore, the chemical and worker safety, and the legislative framework will determine the suitability of a disinfection technique. Current research often focuses on produce decontamination and to a lesser extent on preventing cross-contamination. Further research on a sanitizer’s efficacy in the washing water is recommended at the laboratory scale, in particular with experimental designs reflecting industrial conditions. Validation on the industrial scale is warranted to better understand the overall effects of a sanitizer. PMID:26213953

Comparison of fat maintenance in the face with centrifuge versus filtered and washed fat.

Science.gov (United States)

Asilian, Ali; Siadat, Amir Hossein; Iraji, Razieh

2014-06-01

Autogenous fat injection of the face is a viable and lasting remedy for soft tissue loss and has become a mainstay in facial rejuvenation. Fat transfer as either a stand-alone technique or as an adjunct to other filler technique and lifting depending on patient needs. Although soft tissue augmentation with autologous fat transfer has been increasingly used by esthetic surgeon, but there is no agreement concerning the best way of processing the harvested fat before injection. This study compared the clinical results obtained using simple filtered and washed fat via metal sieve with those achieved by means of pure centrifuged fat. A prospective single-blind analysis on 32 healthy patients undergoing nasolabial fold fat transplantation from 2009 to 2011 (simple sampling). Patients assigned in two groups randomly. The face of half (16 subjects) was injected with centrifuged, another half with simple filtered and washed fat to evaluate the effect of preparation methods on fat graft viability. Objective method was used to evaluate the results, involving the evaluation of postoperative photographs (in month 1, 6 and 12) by an esthetic surgeon (according to the nasolabial scale). Subjective method was a self-assessment obtained from patients about general level of satisfaction and improvement of skin texture, statistical analysis were performed by means of the Wilcoxon and Mann-Whitney test. Acquired data were analyzed using SPSS version 15 and a value of P > 0.05 was considered as significant. There was no significant difference in the survival of grafted fat between the Group 1 (fat-processing with centrifuge at 3400 rpm for 1-min) and Group 2 (washing the fat in the sieve). Our data suggest that the centrifuge of the fat does not enhance survival of grafted fat (P > 0.05).

Modeling Flow Past a Tilted Vena Cava Filter

Energy Technology Data Exchange (ETDEWEB)

Singer, M A; Wang, S L

2009-06-29

Inferior vena cava filters are medical devices used to prevent pulmonary embolism (PE) from deep vein thrombosis. In particular, retrievable filters are well-suited for patients who are unresponsive to anticoagulation therapy and whose risk of PE decreased with time. The goal of this work is to use computational fluid dynamics to evaluate the flow past an unoccluded and partially occluded Celect inferior vena cava filter. In particular, the hemodynamic response to thrombus volume and filter tilt is examined, and the results are compared with flow conditions that are known to be thrombogenic. A computer model of the filter inside a model vena cava is constructed using high resolution digital photographs and methods of computer aided design. The models are parameterized using the Overture software framework, and a collection of overlapping grids is constructed to discretize the flow domain. The incompressible Navier-Stokes equations are solved, and the characteristics of the flow (i.e., velocity contours and wall shear stresses) are computed. The volume of stagnant and recirculating flow increases with thrombus volume. In addition, as the filter increases tilt, the cava wall adjacent to the tilted filter is subjected to low velocity flow that gives rise to regions of low wall shear stress. The results demonstrate the ease of IVC filter modeling with the Overture software framework. Flow conditions caused by the tilted Celect filter may elevate the risk of intrafilter thrombosis and facilitate vascular remodeling. This latter condition also increases the risk of penetration and potential incorporation of the hook of the filter into the vena caval wall, thereby complicating filter retrieval. Consequently, severe tilt at the time of filter deployment may warrant early clinical intervention.

Development of laundry drainage treatment system with ceramic ultra filter

International Nuclear Information System (INIS)

Kanda, Masanori; Kurahasi, Takafumi

1995-01-01

A compact laundry drainage treatment system (UF system hereafter) with a ceramic ultra filter membrane (UF membrane hereafter) has been developed to reduce radioactivity in laundry drainage from nuclear power plants. The UF membrane is made of sintered fine ceramic. The UF membrane has 0.01 μm fine pores, resulting in a durable, heat-resistant, and corrosion-resistant porous ceramic filter medium. A cross-flow system, laundry drainage is filtrated while it flows across the UF membrane, is used as the filtration method. This method creates less caking when compared to other methods. The UF membrane is back washed at regular intervals with permeated water to minimize caking of the filter. The UF membrane and cross-flow system provides long stable filtration. The ceramic UF membrane is strong enough to concentrate suspended solids in laundry drainage up to a weight concentration of 10%. The final concentrated laundry drainage can be treated in an incinerator. The performance of the UF system was checked using radioactive laundry drainage. The decontamination factor of the UF system was 25 or more. The laundry drainage treatment capacity and concentration ratio of the UF system, as well as the service life of the UF membrane were also checked by examination using simulated non-radioactive laundry drainage. Even though laundry drainage was concentrated 1000 times, the UF system showed good permeated water quality and permeated water flux. (author)

FLOWING BILATERAL FILTER: DEFINITION AND IMPLEMENTATIONS

Directory of Open Access Journals (Sweden)

Maxime Moreaud

2015-06-01

Full Text Available The bilateral filter plays a key role in image processing applications due to its intuitive parameterization and its high quality filter result, smoothing homogeneous regions while preserving the edges of the objects. Considering the image as a topological relief, seeing pixel intensities as peaks and valleys, we introduce a way to control the tonal weighting coefficients, the flowing bilateral filter, reducing "halo" artifacts typically produced by the regular bilateral filter around a large peak surrounded by two valleys of lower values. In this paper we propose to investigate exact and approximated versions of CPU and parallel GPU (Graphical Processing Unit based implementations of the regular and flowing bilateral filter using the NVidia CUDA API. Fast implementations of these filters are important for the processing of large 3D volumes up to several GB acquired by x-ray or electron tomography.

Cross flow filtration of aqueous radioactive tank wastes

International Nuclear Information System (INIS)

McCabe, D.J.; Reynolds, B.A.; Todd, T.A.; Wilson, J.H.

1997-01-01

The Tank Focus Area (TFA) of the Department of Energy (DOE) Office of Science and Technology addresses remediation of radioactive waste currently stored in underground tanks. Baseline technologies for treatment of tank waste can be categorized into three types of solid liquid separation: (a) removal of radioactive species that have been absorbed or precipitated, (b) pretreatment, and (c) volume reduction of sludge and wash water. Solids formed from precipitation or absorption of radioactive ions require separation from the liquid phase to permit treatment of the liquid as Low Level Waste. This basic process is used for decontamination of tank waste at the Savannah River Site (SRS). Ion exchange of radioactive ions has been proposed for other tank wastes, requiring removal of insoluble solids to prevent bed fouling and downstream contamination. Additionally, volume reduction of washed sludge solids would reduce the tank space required for interim storage of High Level Wastes. The scope of this multi-site task is to evaluate the solid/liquid separations needed to permit treatment of tank wastes to accomplish these goals. Testing has emphasized cross now filtration with metal filters to pretreat tank wastes, due to tolerance of radiation and caustic

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

Science.gov (United States)

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

High flow ceramic pot filters

NARCIS (Netherlands)

van Halem, D.; van der Laan, H.; Soppe, A. I.A.; Heijman, S.G.J.

2017-01-01

Ceramic pot filters are considered safe, robust and appropriate technologies, but there is a general consensus that water revenues are limited due to clogging of the ceramic element. The objective of this study was to investigate the potential of high flow ceramic pot filters to produce more

Flood potential of Fortymile Wash and its principal southwestern tributaries, Nevada Test Site, Southern Nevada

International Nuclear Information System (INIS)

Squires, R.R.; Young, R.L.

1984-01-01

Flood hazards for a 9-mile reach of Fortymile Wash and its principal southwestern tributaries - Busted Butte, Drill Hole, and Yucca Washes - were evaluated to aid in determining possible sites for the storage of high-level radioactive wastes on the Nevada Test Site. Data from 12 peak-flow gaging stations adjacent to the Test Site were used to develop regression relations that would permit an estimation of the magnitude of the 100- and 500-year flood peaks (Q 100 and Q 500 ), in cubic feet per second. The resulting equations are: Q 100 = 482A 0 565 and Q 500 = 2200A 0 571 , where A is the tributary drainage area, in square miles. The estimate of the regional maximum flood was based on data from extreme floods elsewhere in Nevada and in surrounding states. Among seven cross sections on Fortymile Wash, the estimated maximum depths of the 100-year, 500-year, and regional maximum floods are 8, 11, and 29 feet, respectively. At these depths, flood water would remain within the deeply incised channel of the wash. Mean flow velocities would be as great as 9, 14, and 28 feet per second for the three respective flood magnitudes. The study shows that Busted Butte and Drill Hole Washes (9 and 11 cross sections, respectively) would have water depths of up to at least 4 feet and mean flow velocities of up to at least 8 feet per second during a 100-year flood. A 500-year flood would exceed stream-channel capacities at several places, with depths to 10 feet and mean flow velocities to 11 feet per second. The regional maximum flood would inundate sizeable areas in central parts of the two watersheds. At Yucca Wash (5 cross sections), the 100-year, 500-year, and regional maximum floods would remain within the stream channel. Maximum flood depths would be about 5, 9, and 23 feet and mean velocities about 9, 12, and 22 feet per second, respectively, for the three floods

Irreversible Wash Aid Additive for Cesium Mitigation: WARRP Demonstration

Energy Technology Data Exchange (ETDEWEB)

Kaminski, Michael [Argonne National Lab. (ANL), Argonne, IL (United States)

2015-01-01

This activity demonstrated, on a practical scale, the primary unit operations for building a containment structure for radioactive wash waters, washing down a hypothetically radioactively contaminated vehicle, collecting the hypothetically radioactive slurry waste water, filtering the hypothetically radioactive wash waters, disassembling the containment, and transporting the materials for final disposition.

A surface-renewal model of cross-flow microfiltration

Directory of Open Access Journals (Sweden)

A. Hasan

2013-03-01

Full Text Available A mathematical model using classical cake-filtration theory and the surface-renewal concept is formulated for describing cross-flow microfiltration under dynamic and steady-state conditions. The model can predict the permeate flux and cake buildup in the filter. The three basic parameters of the model are the membrane resistance, specific cake resistance and rate of surface renewal. The model is able to correlate experimental permeate flow rate data in the microfiltration of fermentation broths in laboratory- and pilot-scale units with an average root-mean-square (RMS error of 4.6%. The experimental data are also compared against the critical-flux model of cross-flow microfiltration, which has average RMS errors of 6.3, 5.5 and 6.1% for the cases of cake filtration, intermediate blocking and complete blocking mechanisms, respectively.

Effects of filter housing and ductwork configuration on air flow uniformity inside air cleaning filter housings

International Nuclear Information System (INIS)

Paul, J.D.

1993-01-01

Each new HEPA filter installation presents a different physical configuration based on the system requirements, the available space and designer preference. Each different configuration can result in variations of air flow uniformity inside the filter housing across the filter banks. This paper presents the results of air flow uniformity testing for six different filter housing/ductwork configurations and discusses if any of those variations in air flow uniformity is attributable to the difference in the physical arrangements for the six cases

Filtering Undesirable Flows in Networks

NARCIS (Netherlands)

Polevoy, G.; Trajanovski, S.; Grosso, P.; de Laat, C.; Gao, X.; Du, H.; Han, M.

2017-01-01

We study the problem of fully mitigating the effects of denial of service by filtering the minimum necessary set of the undesirable flows. First, we model this problem and then we concentrate on a subproblem where every good flow has a bottleneck. We prove that unless P=NP, this subproblem is

Baleen Hydrodynamics and Morphology of Cross-Flow Filtration in Balaenid Whale Suspension Feeding.

Directory of Open Access Journals (Sweden)

Alexander J Werth

Full Text Available The traditional view of mysticete feeding involves static baleen directly sieving particles from seawater using a simple, dead-end flow-through filtration mechanism. Flow tank experiments on bowhead (Balaena mysticetus baleen indicate the long-standing model of dead-end filtration, at least in balaenid (bowhead and right whales, is not merely simplistic but wrong. To recreate continuous intraoral flow, sections of baleen were tested in a flume through which water and buoyant particles circulated with variable flow velocity. Kinematic sequences were analyzed to investigate movement and capture of particles by baleen plates and fringes. Results indicate that very few particles flow directly through the baleen rack; instead much water flows anteroposteriorly along the interior (lingual side of the rack, allowing items to be carried posteriorly and accumulate at the posterior of the mouth where they might readily be swallowed. Since water flows mainly parallel to rather than directly through the filter, the cross-flow mechanism significantly reduces entrapment and tangling of minute items in baleen fringes, obviating the need to clean the filter. The absence of copepods or other prey found trapped in the baleen of necropsied right and bowhead whales supports this hypothesis. Reduced through-baleen flow was observed with and without boundaries modeling the tongue and lips, indicating that baleen itself is the main if not sole agent of crossflow. Preliminary investigation of baleen from balaenopterid whales that use intermittent filter feeding suggests that although the biomechanics and hydrodynamics of oral flow differ, cross-flow filtration may occur to some degree in all mysticetes.

Membrane processes for the reuse of car washing wastewater

OpenAIRE

Deniz Uçar

2018-01-01

This study investigates alternative treatments of car wash effluents. The car wash wastewater was treated by settling, filtration, and membrane filtration processes. During settling, total solid concentration decreased rapidly within the first 2 hours and then remained constant. Chemical oxygen demand (COD) and conductivity were decreased by 10% and 4%, respectively. After settling, wastewater was filtered throughout a 100 μm filter. It was found that filtration had a negligible effect on COD...

Comparative study of the performance of three cross-flow ceramic ...

African Journals Online (AJOL)

Several tests using water as effluent are used to analyse the performance of three types of microfiltration cross-flow ceramic membranes. Two of these membranes are commercial (Atech and Membralox/US Filter) and the third one is experimental. The main differences between them lie in their chemical composition ...

Bench-scale cross flow filtration of Tank S-107 sludge slurries and Tank C-107 supernatant

International Nuclear Information System (INIS)

Geeting, J.G.H.; Reynolds, B.A.

1996-10-01

Hanford tank waste filtration experiments were conducted using a bench-scale cross flow filter on 8 wt%, 1.5 wt%, and 0.05 wt% Tank S- 107 sludge slurries and on Tank C-107 supernatant. For comparison, two simulants each with solids loadings of 8 wt% and 0.05 wt% were also tested. The purpose of the tests was to determine the efficacy of cross flow filtration on slurries of various solids loadings. -In addition, filtrate flux dependency on axial velocity and transmembrane pressure was sought so that conditions for future experiments might be better selected. The data gathered are compared to the simulants and three cross flow filtration models. A two- parameter central composite design which tested. transmembrane pressure from 5 to 40 psig and axial Velocity from 3 to 9 ft/s was used for all feeds. The cross flow filter effectively removed solids from the liquid, as 19 of 20 filtrate samples had particle concentrations below the resolution limit of the photon correlation spectrometer used in the Hanford Radiocolloid Laboratory. Radiochemical analysis indicate that all filtrate samples were below Class A waste classification standards for 9OSr and transuranics

Filtered Rayleigh Scattering Measurements in a Buoyant Flow Field

National Research Council Canada - National Science Library

Meents, Steven M

2008-01-01

Filtered Rayleigh Scattering (FRS) is a non-intrusive, laser-based flow characterization technique that consists of a narrow linewidth laser, a molecular absorption filter, and a high resolution camera behind the filter to record images...

Exploring the gap between hand washing knowledge and practices in Bangladesh: a cross-sectional comparative study.

Science.gov (United States)

Rabbi, Sifat E; Dey, Nepal C

2013-01-30

Hand washing is considered as one of the most effective hygiene promotion activities for public health in developing countries. This study compared hand washing knowledge and practices in BRAC's water; sanitation and hygiene (WASH) programme areas over time. This study is a cross-sectional comparative study between baseline (2006), midline (2009) and end-line (2011) surveys in 50 sub-districts from the first phase of the programme. Thirty thousand households from 50 sub-districts were selected in two steps: i) 30 villages were selected from each sub-district by cluster sampling, and ii) 20 households were chosen systematically from each village. The matched households were considered (26,404 in each survey) for analysis. Data were collected from households through face-to-face interview using a pre-tested questionnaire. Respondents were the adult female members of the same households, who had knowledge of day-to-day household activities related to water, sanitation and hygiene. A gap between perception and practice of proper hand washing practices with soap was identified in the study areas. Hand washing practice with soap before eating was much lower than after defecation. In baseline data, 8% reported to wash their hands with soap which significantly increased to 22% in end line. Hand washing knowledge and practices before cooking food, before serving food and while handling babies is considerably limited than other critical times. A multivariate analysis shows that socio-economic factors including education of household head and respondent, water availability and access to media have strong positive association with hand washing with soap. Gap between knowledge and practice still persists in hand washing practices. Long term and extensive initiatives can aware people about the effectiveness of hand washing.

Exploring the gap between hand washing knowledge and practices in Bangladesh: a cross-sectional comparative study

Directory of Open Access Journals (Sweden)

Rabbi Sifat E

2013-01-01

Full Text Available Abstract Background Hand washing is considered as one of the most effective hygiene promotion activities for public health in developing countries. This study compared hand washing knowledge and practices in BRAC’s water; sanitation and hygiene (WASH programme areas over time. Methods This study is a cross-sectional comparative study between baseline (2006, midline (2009 and end-line (2011 surveys in 50 sub-districts from the first phase of the programme. Thirty thousand households from 50 sub-districts were selected in two steps: i 30 villages were selected from each sub-district by cluster sampling, and ii 20 households were chosen systematically from each village. The matched households were considered (26,404 in each survey for analysis. Data were collected from households through face-to-face interview using a pre-tested questionnaire. Respondents were the adult female members of the same households, who had knowledge of day-to-day household activities related to water, sanitation and hygiene. Results A gap between perception and practice of proper hand washing practices with soap was identified in the study areas. Hand washing practice with soap before eating was much lower than after defecation. In baseline data, 8% reported to wash their hands with soap which significantly increased to 22% in end line. Hand washing knowledge and practices before cooking food, before serving food and while handling babies is considerably limited than other critical times. A multivariate analysis shows that socio-economic factors including education of household head and respondent, water availability and access to media have strong positive association with hand washing with soap. Conclusion Gap between knowledge and practice still persists in hand washing practices. Long term and extensive initiatives can aware people about the effectiveness of hand washing.

Simulation of the air flows in many industrial pleated filters

International Nuclear Information System (INIS)

Del Fabbro, L.; Brun, P.; Laborde, J.C.; Lacan, J.; Ricciardi, L.; Renoux, A.

2000-01-01

The study presents results concerning the characterization of the charge loss and the air flow in nuclear and automobile type pleated filters. The experimental studies in correlation with the numerical models showed an homogenous distribution of the air flows in a THE nuclear type filter, whereas the distribution is heterogenous in the case of an automobile filter. (A.L.B.)

Application of Micropore Filter Technology: Exploring the Blood Flow Path in Arterial-Line Filters and Its Effect on Bubble Trapping Functions.

Science.gov (United States)

Herbst, Daniel P

2017-03-01

Conventional arterial-line filters commonly use a large volume circular shaped housing, a wetted micropore screen, and a purge port to trap, separate, and remove gas bubbles from extracorporeal blood flow. Focusing on the bubble trapping function, this work attempts to explore how the filter housing shape and its resulting blood flow path affect the clinical application of arterial-line filters in terms of gross air handling. A video camera was used in a wet-lab setting to record observations made during gross air-bolus injections in three different radially designed filters using a 30-70% glycerol-saline mixture flowing at 4.5 L/min. Two of the filters both had inlet ports attached near the filter-housing top with bottom oriented outlet ports at the bottom, whereas the third filter had its inlet and outlet ports both located at the bottom of the filter housing. The two filters with top-in bottom-out fluid paths were shown to direct the incoming flow downward as it passed through the filter, placing the forces of buoyancy and viscous drag in opposition to each other. This contrasted with the third filter's bottom-in bottom-out fluid path, which was shown to direct the incoming flow upward so that the forces of buoyancy and viscous drag work together. The direction of the blood flow path through a filter may be important to the application of arterial-line filter technology as it helps determine how the forces of buoyancy and flow are aligned with one another.

Cross-flow electrochemical reactor cells, cross-flow reactors, and use of cross-flow reactors for oxidation reactions

Science.gov (United States)

Balachandran, Uthamalingam; Poeppel, Roger B.; Kleefisch, Mark S.; Kobylinski, Thaddeus P.; Udovich, Carl A.

1994-01-01

This invention discloses cross-flow electrochemical reactor cells containing oxygen permeable materials which have both electron conductivity and oxygen ion conductivity, cross-flow reactors, and electrochemical processes using cross-flow reactor cells having oxygen permeable monolithic cores to control and facilitate transport of oxygen from an oxygen-containing gas stream to oxidation reactions of organic compounds in another gas stream. These cross-flow electrochemical reactors comprise a hollow ceramic blade positioned across a gas stream flow or a stack of crossed hollow ceramic blades containing a channel or channels for flow of gas streams. Each channel has at least one channel wall disposed between a channel and a portion of an outer surface of the ceramic blade, or a common wall with adjacent blades in a stack comprising a gas-impervious mixed metal oxide material of a perovskite structure having electron conductivity and oxygen ion conductivity. The invention includes reactors comprising first and second zones seprated by gas-impervious mixed metal oxide material material having electron conductivity and oxygen ion conductivity. Prefered gas-impervious materials comprise at least one mixed metal oxide having a perovskite structure or perovskite-like structure. The invention includes, also, oxidation processes controlled by using these electrochemical reactors, and these reactions do not require an external source of electrical potential or any external electric circuit for oxidation to proceed.

Risk of bacterial cross infection associated with inspiration through flow-based spirometers.

Science.gov (United States)

Bracci, Massimo; Strafella, Elisabetta; Croce, Nicola; Staffolani, Sara; Carducci, Annalaura; Verani, Marco; Valentino, Matteo; Santarelli, Lory

2011-02-01

Bacterial contamination of spirometers has been documented in water-sealed devices, mouthpieces, and connection tubes. Little information is available about bacterial contamination of flow-based apparatuses such as turbine-type spirometers and pneumotachographs. Inspiration through contaminated equipment is a potential source of cross infection. To investigate bacteria mobilization (ie, bacteria detachment and aerosolization from the instrument) during routine spirometric testing, 2 types of flow-based spirometers were used. Bacteria mobilization during artificial inspiration through in-line filters or cardboard mouthpieces was evaluated. Nine hundred workers undergoing periodic spirometric testing were enrolled at the occupational physician office in 30 sessions of 30 subjects each. The participants were asked to perform a forced vital capacity test in a turbine-type spirometer and in an unheated pneumotachograph fitted with disposable in-line filters or cardboard mouthpieces. To evaluate bacterial mobilization, an artificial inspiration was performed and bacterial growth determined. The bacterial growth analysis was assessed after the first and the thirtieth spirometric tests of each session without disinfecting the instruments between tests. In addition, instrument bacterial contamination was evaluated. No significant bacterial mobilization and instrument contamination were found in spirometric tests executed with in-line filters. Conversely, a significant bacterial mobilization and instrument contamination were observed in tests performed with cardboard mouthpieces. Differences between the 2 spirometers were not significant. In-line filters may effectively reduce the risk of bacterial cross infection. Inspiration through flow-based spirometers fitted with disposable cardboard mouthpieces is completely safe when combined with spirometer disinfection/sterilization between subjects. Copyright © 2011 Association for Professionals in Infection Control and

Final Report: Pilot-scale Cross-flow Filtration Test - Envelope A + Entrained Solids

International Nuclear Information System (INIS)

Duignan, M.R.

2000-01-01

This report discusses the results of the operation of a cross-flow filter in a pilot-scale experimental facility that was designed, built, and run by the Experimental Thermal Fluids Laboratory of the Savannah River Technology Center of the Westinghouse Savannah River Company.This filter technology was evaluated for its inclusion in the pretreatment section of the nuclear waste stabilization plant being designed by BNFL, Inc. This plant will be built at the U.S. Department of Energy's Hanford Site as part of the River Protection Project

Real world efficiency of retrofit partial-flow diesel particulate filters for trucks

International Nuclear Information System (INIS)

Van Asch, R.; Verbeek, R.; Ligterink, N.; Kadijk, G.

2009-11-01

In 2006 the Dutch Ministry of Housing, Spatial Planning and the Environment (VROM) introduced an incentive scheme for retrofitting diesel particulate filters on Euro II and Euro III trucks. This scheme involves both partial flow and full flow diesel particulate filters (also called semi-open or open respectively wall-flow or closed filters). In the period 2007 till January 2009 about 15,000 partial flow filters and 8,000 full flow diesel particulate filters were installed. The minimum filtration efficiency requirement for the partial flow diesel particulate filters is 50% during the type approval test. In 2008 an engine dynamometer test programme was conducted to measure the filtration efficiency of retrofit open particulates filters of heavy trucks. This led to somewhat disappointing results with average filtration efficiencies in the range of 5-20% during city and national motorway driving conditions up to 20-40% during long distance motorway driving. This result leads to two main questions: (1) Is this result also representative for medium heavy trucks used for delivery, and (2) do similar efficiencies show up also in tests on entire vehicles, tested under conditions as close as possible to their real world usage profile. To this end, an additional measurement programme was defined, which is reported here. The objective of the study reported here is to determine the real world filtration efficiency of retrofit partial flow particulate filters for a number of trucks under different driving conditions such as city and motorway driving. The emphasis should be on medium heavy trucks typically used for national delivery.

Using the developed cross-flow filtration chip for collecting blood plasma under high flow rate condition and applying the immunoglobulin E detection

Science.gov (United States)

Yeh, Chia-Hsien; Hung, Chia-Wei; Wu, Chun-Han; Lin, Yu-Cheng

2014-09-01

This paper presents a cross-flow filtration chip for separating blood cells (white blood cells, red blood cells, and platelets) and obtaining blood plasma from human blood. Our strategy is to flow the sample solution in parallel to the membrane, which can generate a parallel shear stress to remove the clogging microparticles on the membrane, so the pure sample solution is obtained in the reservoir. The cross-flow filtration chip includes a cross-flow layer, a Ni-Pd alloy micro-porous membrane, and a reservoir layer. The three layers are packaged in a polymethylmethacrylate (PMMA) frame to create the cross-flow filtration chip. Various dilutions of the blood sample (original, 2 × , 3 × , 5 × , and 10×), pore sizes with different diameters (1 µm, 2 µm, 4 µm, 7 µm, and 10 µm), and different flow rates (1 mL/min, 3 mL/min, 5 mL/min, 7 mL/min, and 10 mL/min) are tested to determine their effects on filtration percentage. The best filtration percentage is 96.2% when the dilution of the blood sample is 10 × , the diameter of pore size of a Ni-Pd alloy micro-porous membrane is 2 µm, and the flow rate is 10 mL/min. Finally, for the clinical tests of the immunoglobulin E (IgE) concentration, the cross-flow filtration chip is used to filter the blood of the allergy patients to obtain the blood plasma. This filtered blood plasma is compared with that obtained using the conventional centrifugation based on the enzyme-linked immunosorbent assay. The results reveal that these two blood separation methods have similar detection trends. The proposed filtration chip has the advantages of low cost, short filtration time, and easy operation and thus can be applied to the separation of microparticles, cells, bacteria, and blood.

Using the developed cross-flow filtration chip for collecting blood plasma under high flow rate condition and applying the immunoglobulin E detection

International Nuclear Information System (INIS)

Yeh, Chia-Hsien; Hung, Chia-Wei; Lin, Yu-Cheng; Wu, Chun-Han

2014-01-01

This paper presents a cross-flow filtration chip for separating blood cells (white blood cells, red blood cells, and platelets) and obtaining blood plasma from human blood. Our strategy is to flow the sample solution in parallel to the membrane, which can generate a parallel shear stress to remove the clogging microparticles on the membrane, so the pure sample solution is obtained in the reservoir. The cross-flow filtration chip includes a cross-flow layer, a Ni-Pd alloy micro-porous membrane, and a reservoir layer. The three layers are packaged in a polymethylmethacrylate (PMMA) frame to create the cross-flow filtration chip. Various dilutions of the blood sample (original, 2 × , 3 × , 5 × , and 10×), pore sizes with different diameters (1 µm, 2 µm, 4 µm, 7 µm, and 10 µm), and different flow rates (1 mL/min, 3 mL/min, 5 mL/min, 7 mL/min, and 10 mL/min) are tested to determine their effects on filtration percentage. The best filtration percentage is 96.2% when the dilution of the blood sample is 10 × , the diameter of pore size of a Ni-Pd alloy micro-porous membrane is 2 µm, and the flow rate is 10 mL/min. Finally, for the clinical tests of the immunoglobulin E (IgE) concentration, the cross-flow filtration chip is used to filter the blood of the allergy patients to obtain the blood plasma. This filtered blood plasma is compared with that obtained using the conventional centrifugation based on the enzyme-linked immunosorbent assay. The results reveal that these two blood separation methods have similar detection trends. The proposed filtration chip has the advantages of low cost, short filtration time, and easy operation and thus can be applied to the separation of microparticles, cells, bacteria, and blood. (paper)

Conceptual considerations of evaluate internal erosion phenomenon via no-erosion filter test and continuing erosion filter test

Directory of Open Access Journals (Sweden)

Ramos-Rivera Johnatan

2016-01-01

Full Text Available Some widely-graded soils may exhibit, under the influence of steady seepage flow, a behaviour in which grains of the finer fraction migrate through the interstices of the matrix formed by the coarser fraction. The migrating fines may accumulate at a downstream location within the soil. Alternatively, and where there is no capacity for retention at the downstream or exit boundary, the behaviour may lead to a washing out and consequent loss of the finer fraction. The phenomenon of erosion is termed internal instability, and the soils are considered internally unstable. Taking into consideration (i the specimen reconstitution by method of compaction, (ii the application of a vertical stress to the specimen, and (iii the use of multi-stage seepage flow with head-control, to measure the origin of a conduit through the coarser fraction, some test devices were conducted by different authors to evaluate this phenomenon, the purpose of this paper is to present some considerations and key aspects about internal erosion in dams and filter compatibility with core material (specimen reconstitution, test procedure, consolidation, seepage flow, test program and its relevance to the reality. The main reason to present this investigation is due to the absence of any specified regulatory or standard test method. Given the importance of filter compatibility of the zoned earth core dam and filter materials, as well the grading stability of each zone in the presence of seepage flow, additional consideration will be given to performing Continuing Erosion Filter (CEF tests on the core-filter interface, using the laboratory permeameter device.

Effect of a topical glucocorticoid, budesonide, on nasal mucosal blood flow as measured with 133Xe wash-out technique

International Nuclear Information System (INIS)

Bende, M.; Lindqvist, N.; Pipkorn, U.

1983-01-01

The ''vasoconstrictor'' effect of dermally applicated steroids is a widely used parameter when determining the potency of glucocorticoids. A similar effect on the nasal mucosa has been suggested as providing an explanation for the clinical effect of topically administered glucocorticoids in the treatment of nasal disorders such as allergic and vasomotor rhinitis. The recently described 133 Xe wash-out method was used for the purpose of blood flow determination in 11 healthy subjects. In a randomized double-blind cross-over study, the effect of topically administered budesonide, a non-halogenated glucocorticoid, for 1 week was compared with that of placebo. No difference was found to occur in the mucosal blood flow after the administration of budesonide, as compared with placebo. It seems likely that a more complex activity than vasoconstriction is responsible for the clinical effect in the treatment of nasal disorders, and further research is required in order to clarify this issue. (author)

Final Report: Pilot-scale Cross-flow Filtration Test - Envelope A + Entrained Solids

Energy Technology Data Exchange (ETDEWEB)

Duignan, M.R.

2000-06-27

This report discusses the results of the operation of a cross-flow filter in a pilot-scale experimental facility that was designed, built, and run by the Experimental Thermal Fluids Laboratory of the Savannah River Technology Center of the Westinghouse Savannah River Company.This filter technology was evaluated for its inclusion in the pretreatment section of the nuclear waste stabilization plant being designed by BNFL, Inc. This plant will be built at the U.S. Department of Energy's Hanford Site as part of the River Protection Project.

Energy Based Clutter Filtering for Vector Flow Imaging

DEFF Research Database (Denmark)

Villagómez Hoyos, Carlos Armando; Jensen, Jonas; Ewertsen, Caroline

2017-01-01

for obtaining vector flow measurements, since the spectra overlaps at high beam-to-flow angles. In this work a distinct approach is proposed, where the energy of the velocity spectrum is used to differentiate among the two signals. The energy based method is applied by limiting the amplitude of the velocity...... spectrum function to a predetermined threshold. The effect of the clutter filtering is evaluated on a plane wave (PW) scan sequence in combination with transverse oscillation (TO) and directional beamforming (DB) for velocity estimation. The performance of the filter is assessed by comparison...

Ultrafiltration to reuse laundering wash water

DEFF Research Database (Denmark)

Giagnorio, Mattia; Søtoft, Lene Fjerbæk; Tiraferri, Alberto

2017-01-01

Laundering industry consumes and discharges large amounts of water and surfactants, and the demand of surface active agents used for washing is increasing worldwide. Some of these substances are considered contaminants of emerging concern, as they persist in the environment. This work aimed...... at evaluating the feasibility of ultrafiltration as a method to treat the wash wastewater and possibly reuse the surfactant-rich permeate stream in laundry facilities. In particular, evaluation of surfactant recovery was performed through analysis of the permeate flux and properties obtained through polymeric...... and ceramic membranes. Wash water samples were collected at an industrial laundering facility for hospital linen and filtered through different ultrafiltration membranes with varying molecular weight cut-off. The critical micelle concentration of the detergent was quantified, and capillarity measurements were...

Prevention of airborne contamination and cross-contamination in germ-free mice by laminar flow

NARCIS (Netherlands)

Waaij, D. van der; Andres, A.H.

1971-01-01

The efficacy of horizontal and vertical laminar flow units (equipped with high-efficiency air filters) in the prevention of cross-contamination between cages and of contamination from outside has been demonstrated. With germ-free mice and using germ-free standard techniques for sterilization and for

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

Science.gov (United States)

Daum, Fred; Huang, Jim

2011-06-01

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

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

Application of velocity filtering to optical-flow passive ranging

Science.gov (United States)

Barniv, Yair

1992-01-01

The performance of the velocity filtering method as applied to optical-flow passive ranging under real-world conditions is evaluated. The theory of the 3-D Fourier transform as applied to constant-speed moving points is reviewed, and the space-domain shift-and-add algorithm is derived from the general 3-D matched filtering formulation. The constant-speed algorithm is then modified to fit the actual speed encountered in the optical flow application, and the passband of that filter is found in terms of depth (sensor/object distance) so as to cover any given range of depths. Two algorithmic solutions for the problems associated with pixel interpolation and object expansion are developed, and experimental results are presented.

Computational Modeling of Blood Flow in the TrapEase Inferior Vena Cava Filter

Energy Technology Data Exchange (ETDEWEB)

Singer, M A; Henshaw, W D; Wang, S L

2008-02-04

To evaluate the flow hemodynamics of the TrapEase vena cava filter using three dimensional computational fluid dynamics, including simulated thrombi of multiple shapes, sizes, and trapping positions. The study was performed to identify potential areas of recirculation and stagnation and areas in which trapped thrombi may influence intrafilter thrombosis. Computer models of the TrapEase filter, thrombi (volumes ranging from 0.25mL to 2mL, 3 different shapes), and a 23mm diameter cava were constructed. The hemodynamics of steady-state flow at Reynolds number 600 was examined for the unoccluded and partially occluded filter. Axial velocity contours and wall shear stresses were computed. Flow in the unoccluded TrapEase filter experienced minimal disruption, except near the superior and inferior tips where low velocity flow was observed. For spherical thrombi in the superior trapping position, stagnant and recirculating flow was observed downstream of the thrombus; the volume of stagnant flow and the peak wall shear stress increased monotonically with thrombus volume. For inferiorly trapped spherical thrombi, marked disruption to the flow was observed along the cava wall ipsilateral to the thrombus and in the interior of the filter. Spherically shaped thrombus produced a lower peak wall shear stress than conically shaped thrombus and a larger peak stress than ellipsoidal thrombus. We have designed and constructed a computer model of the flow hemodynamics of the TrapEase IVC filter with varying shapes, sizes, and positions of thrombi. The computer model offers several advantages over in vitro techniques including: improved resolution, ease of evaluating different thrombus sizes and shapes, and easy adaptation for new filter designs and flow parameters. Results from the model also support a previously reported finding from photochromic experiments that suggest the inferior trapping position of the TrapEase IVC filter leads to an intra-filter region of recirculating

A constant flow filter air sampler for workplace environments

International Nuclear Information System (INIS)

Parulian, A.; Rodgers, J.C.; McFarland, A.R.

1996-01-01

A filter air sampler has been developed for sampling radionuclide aerosol particles form the workplace environment. It provides easy filter changing, constant flow sampling, and a visual display to indicate proper operation. An experimental study was conducted to characterize the collection efficiency of the sampler as affected by variations in room air velocity, particle size, sampling flow rate, inlet geometry, and inlet orientation to the free stream. Tests were carried out in a wing tunnel at velocities between 0.3 m s -1 and 2.0 m s -1 , which is a range that covers anticipated velocities in the typical highly ventilated workplace environment of a nuclear facility. Nearly monodisperse aerosols with sizes between 5 and 20 μm aerodynamic diameter were sampled at flow rates between 28.3 and 84.9 L min -1 . Inlet orientations of 0 degree, 90 degree, and 180 degree from the horizontal were selected for evaluation. When the sampler was oriented at 0 degree over various ranges of free stream velocities, sampling flow rates and particle sizes, the transmission efficiency of aerosol was typically greater than 95%. The transmission efficiencies varied form 80% to 106% for 10-μm aerodynamic diameter particles over the previously noted range of free stream velocities and inlet orientations. Uniformity of deposits of 10 μm aerodynamic diameter particles on collection filters was examined for a sampling rate of 57 L min -1 , a sampler orientation of 90 degree into the wind and wind speeds of 0.3-2 m s -1 . The coefficients of variation for the areal density of the deposits ranged from 6.1% to 37.2%. A miniature critical flow venturi with a constant sampling flow rate of 57 L min -1 was developed for application to the new filter air sampler. It was demonstrated that the performance of the new filter air sampler is quite acceptable over a wide range of conditions. 31 refs., 8 figs., 1 tab

Counter current decantation washing of HLW sludge

International Nuclear Information System (INIS)

Brooke, J.N.; Peterson, R.A.

1997-01-01

The Savannah River Site (SRS) has 51 High Level Waste (HLW) tanks with typical dimensions 25.9 meters (85 feet) diameter and 10 meters (33 feet) high. Nearly 114 million liters (30 M gallons) of HLW waste is stored in these tanks in the form of insoluble solids called sludge, crystallized salt called salt cake, and salt solutions. This waste is being converted to waste forms stable for long term storage. In one of the processes, soluble salts are washed from HLW sludge in preparation for vitrification. At present, sludge is batch washed in a waste tank with one or no reuse of the wash water. Sodium hydroxide and sodium nitrite are added to the wash water for tank corrosion protection; the large volumes of spent wash water are recycled to the evaporator system; additional salt cake is produced; and sodium carbonate is formed in the washed sludge during storage by reaction with CO 2 from the air. High costs and operational concerns with the current washing process prompts DOE and WSRC to seek an improved washing method. A new method should take full advantage of the physical/chemical properties of sludge, experience from other technical disciplines, processing rate requirements, inherent process safety, and use of proven processes and equipment. Counter current solids washing is a common process in the minerals processing and chemical industries. Washing circuits can be designed using thickeners, filters or centrifuges. Realizing the special needs of nuclear work and the low processing rates required, a Counter Current Decantation (CCD) circuit is proposed using small thickeners and fluidic pumps

A new fold-cross metal mesh filter for suppressing side lobe leakage in terahertz region

Science.gov (United States)

Lu, Changgui; Qi, Zhengqing; Guo, Wengao; Cui, Yiping

2018-04-01

In this paper we propose a new type of fold-cross metal mesh band pass filter, which keeps diffraction side lobe far away from the main transmission peak and shows much better side lobe suppression. Both experimental and theoretical studies are made to analyze the mechanism of side lobe. Compared to the traditional cross filter, the fold-cross filter has a much lower side lobe with almost the same central frequency, bandwidth and highest transmission about 98%. Using the photolithography and electroplating techniques, we experimentally extend the distance between the main peak and diffraction side lobe to larger than 1 THz for the fold-cross filter, which is two times larger than the cross filter while maintaining the main peak transmissions of 89% at 1.25 THz for the two structures. This type of single layer substrate-free fold-cross metal structure shows better design flexibility and structure reliability with the introduction of fold arms for metal mesh band pass filters.

Modeling Flow Rate to Estimate Hydraulic Conductivity in a Parabolic Ceramic Water Filter

Directory of Open Access Journals (Sweden)

Ileana Wald

2012-01-01

Full Text Available In this project we model volumetric flow rate through a parabolic ceramic water filter (CWF to determine how quickly it can process water while still improving its quality. The volumetric flow rate is dependent upon the pore size of the filter, the surface area, and the height of water in the filter (hydraulic head. We derive differential equations governing this flow from the conservation of mass principle and Darcy's Law and find the flow rate with respect to time. We then use methods of calculus to find optimal specifications for the filter. This work is related to the research conducted in Dr. James R. Mihelcic's Civil and Environmental Engineering Lab at USF.

Reverse osmosis for wash water recovery in space vehicles.

Science.gov (United States)

Lawrence, R. W.; Saltonstall, C. W., Jr.

1973-01-01

Tests were carried out on both synthetic and real wash water derived from clothes laundry to determine the utility of reverse osmosis in recovering the water for recycle use. A blend membrane made from cellulose di- and triacetates, and a cross-linked cellulose acetate/methacrylate were evaluated. Both were found acceptable. A number of detergents were evaluated, including a cationic detergent, sodium dodecyl sulfate, potassium palmitate, and sodium dodecylbenzenesulfonate. The tests were all made at a temperature of 165 F to minimize microbial growth. Long-term (15 to 30 day) runs were made at 600 and 400 psi on laundry water which was pretreated either by alum addition and sand filtration or by filtration only through 0.5 micron filters. A 30-day run was made using a 2-in. diameter by 22-in. long spiral module at 400 psig with filtering as the pretreatment. The membrane fouling by colloidal matter was found to be controllable. The unit produced initially 55 gal/day and 27 gal/day after 30 days.

New Evidence That Nonlinear Source-Filter Coupling Affects Harmonic Intensity and fo Stability During Instances of Harmonics Crossing Formants.

Science.gov (United States)

Maxfield, Lynn; Palaparthi, Anil; Titze, Ingo

2017-03-01

The traditional source-filter theory of voice production describes a linear relationship between the source (glottal flow pulse) and the filter (vocal tract). Such a linear relationship does not allow for nor explain how changes in the filter may impact the stability and regularity of the source. The objective of this experiment was to examine what effect unpredictable changes to vocal tract dimensions could have on fo stability and individual harmonic intensities in situations in which low frequency harmonics cross formants in a fundamental frequency glide. To determine these effects, eight human subjects (five male, three female) were recorded producing fo glides while their vocal tracts were artificially lengthened by a section of vinyl tubing inserted into the mouth. It was hypothesized that if the source and filter operated as a purely linear system, harmonic intensities would increase and decrease at nearly the same rates as they passed through a formant bandwidth, resulting in a relatively symmetric peak on an intensity-time contour. Additionally, fo stability should not be predictably perturbed by formant/harmonic crossings in a linear system. Acoustic analysis of these recordings, however, revealed that harmonic intensity peaks were asymmetric in 76% of cases, and that 85% of fo instabilities aligned with a crossing of one of the first four harmonics with the first three formants. These results provide further evidence that nonlinear dynamics in the source-filter relationship can impact fo stability as well as harmonic intensities as harmonics cross through formant bandwidths. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

A granular refillable filter for glas-flows contaminated by radioactive impurities

International Nuclear Information System (INIS)

Bonn, J.W.

1975-01-01

Description is given of a granular charcoal refillable filter adapted to adsorb the radioactive impurities of a gaseous flow. That flow comprises a number of filtering layers, the consumed charcoal of which can be discharged by a pneumatic device without exposing the personnel to radioactivity. This can be applied to emergency devices in nuclear facilities [fr

Hanford phosphate precipitation filtration process evaluation

International Nuclear Information System (INIS)

Walker, B.W.; McCabe, D.J.

1997-01-01

The purpose of this filter study was to evaluate cross-flow filtration as effective solid-liquid separation technology for treating Hanford wastes, outline operating conditions for equipment, examine the expected filter flow rates, and determine proper cleaning. A proposed Hanford waste pre-treatment process uses sodium hydroxide at high temperature to remove aluminum from sludge. This process also dissolves phosphates. Upon cooling to 40 degrees centigrade the phosphates form a Na7(PO4)2F9H2O precipitate which must be removed prior to further treatment. Filter studies were conducted with a phosphate slurry simulant to evaluate whether 0.5 micron cross-flow sintered metal Mott filters can separate the phosphate precipitate from the wash solutions. The simulant was recirculated through the filters at room temperature and filtration performance data was collected

Treatment of car wash wastewater by UF membranes

Science.gov (United States)

Istirokhatun, Titik; Destianti, Puti; Hargianintya, Adenira; Oktiawan, Wiharyanto; Susanto, Heru

2015-12-01

The existence of car wash service facilitates car owners to remove dirt and grime from their vehicles. However, the dirt washed off vehicles as well as the cleaning materials themselves may be harmful to the environment if they are not properly managed and discharged. Many technologies have been proposed to treat car wash wastewater such as coagulation flocculation, tricking filter and flocculation-flotation. Nevertheless, these technologies have low efficiency to eliminate oil and small organic compounds. Ultrafiltration (UF) membranes were used in this study to treat car wash wastewater. This study investigated the performance of UF membranes under various pressures to remove COD, oil and grease, and also turbidity from car wash waste water. The membrane performance was examined by investigation of permeate flux and membrane rejection. The results meet the standard of environmental regulation and it is possible to be reused. The highest rejection was shown by PES10 (polyethersulfone 10 kDa) in 1 bar operation with complete rejection for both turbidity and oil and grace and 95% rejection for COD.

Substance Flow Analysis and Source Mapping of Chemical UV-filters

International Nuclear Information System (INIS)

Eriksson, E.; Andersen, H. R.; Ledin, A.

2008-01-01

Chemical ultraviolet (UV)-filters are used in sunscreens to protect the skin from harmful UV radiation which may otherwise cause sunburns and skin cancer. Commonly used chemical UV-filters are known to cause endocrine disrupting effects in both aquatic and terrestrial animals as well as in human skin cells. Here, source mapping and substance flow analysis were applied to find the sources of six UV-filters (oxybenzone, avobenzone, 4-methylbenzylidene camphor, octyl methoxycinnamate, octyl dimethyl PABA and homosalate) and to identify the most dominant flows of these substances in Denmark. Urban water, composed of wastewater and surface waters, was found to be the primary recipient of UV-filters, whereby wastewater received an estimated 8.5-65 tonnes and surface waters received 7.1-51 tonnes in 2005. In wastewater treatment plants, their sorption onto sludge is perceived to be an important process and presence in effluents can be expected due to a lack of biodegradability. In addition, the use of UV-filters is expected to continue to increase significantly. Not all filters (e.g., octyl dimethyl PABA and homosalate) are used in Denmark. For example, 4-MBC is mainly associated with self-tanning liquids and private import of sunscreens

Substance Flow Analysis and Source Mapping of Chemical UV-filters

Energy Technology Data Exchange (ETDEWEB)

Eriksson, E., E-mail: eve@env.dtu.dk; Andersen, H. R.; Ledin, A. [Technical University of Denmark, Department of Environmental Engineering (Denmark)

2008-12-15

Chemical ultraviolet (UV)-filters are used in sunscreens to protect the skin from harmful UV radiation which may otherwise cause sunburns and skin cancer. Commonly used chemical UV-filters are known to cause endocrine disrupting effects in both aquatic and terrestrial animals as well as in human skin cells. Here, source mapping and substance flow analysis were applied to find the sources of six UV-filters (oxybenzone, avobenzone, 4-methylbenzylidene camphor, octyl methoxycinnamate, octyl dimethyl PABA and homosalate) and to identify the most dominant flows of these substances in Denmark. Urban water, composed of wastewater and surface waters, was found to be the primary recipient of UV-filters, whereby wastewater received an estimated 8.5-65 tonnes and surface waters received 7.1-51 tonnes in 2005. In wastewater treatment plants, their sorption onto sludge is perceived to be an important process and presence in effluents can be expected due to a lack of biodegradability. In addition, the use of UV-filters is expected to continue to increase significantly. Not all filters (e.g., octyl dimethyl PABA and homosalate) are used in Denmark. For example, 4-MBC is mainly associated with self-tanning liquids and private import of sunscreens.

Cross flow electrofilter and method

Science.gov (United States)

Gidaspow, Dimitri; Lee, Chang H.; Wasan, Darsh T.

1981-01-01

A filter for clarifying carbonaceous liquids containing finely divided solid particles of, for instance, unreacted coal, ash and other solids discharged from a coal liquefaction process is presented. The filter includes two passageways separated by a porous filter medium. In one preferred embodiment the filter medium is of tubular shape to form the first passageway and is enclosed within an outer housing to form the second passageway within the annulus. An electrode disposed in the first passageway, for instance along the tube axis, is connected to a source of high voltage for establishing an electric field between the electrode and the filter medium. Slurry feed flows through the first passageway tangentially to the surfaces of the filter medium and the electrode. Particles from the feed slurry are attracted to the electrode within the first passageway to prevent plugging of the porous filter medium while carbonaceous liquid filters into the second passageway for withdrawal. Concentrated slurry is discharged from the first passageway at an end opposite to the feed slurry inlet. Means are also provided for the addition of diluent and a surfactant into the slurry to control relative permittivity and the electrophoretic mobility of the particles.

Cross-flow electrofilter and method

Science.gov (United States)

Gidaspow, Dimitri; Lee, Chang H.; Wasan, Darsh T.

1980-01-01

A filter for clarifying carbonaceous liquids containing finely divided solid particles of, for instance, unreacted coal, ash and other solids discharged from a coal liquefaction process is presented. The filter includes two passageways separated by a porous filter medium. In one preferred embodiment the filter medium is of tubular shape to form the first passageway and is enclosed within an outer housing to form the second passageway within the annulus. An electrode disposed in the first passageway, for instance along the tube axis, is connected to a source of high voltage for establishing an electric field between the electrode and the filter medium. Slurry feed flows through the first passageway tangentially to the surfaces of the filter medium and the electrode. Particles from the feed slurry are attracted to the electrode within the first passageway to prevent plugging of the porous filter medium while carbonaceous liquid filters into the second passageway for withdrawal. Concentrated slurry is discharged from the first passageway at an end opposite to the feed slurry inlet. Means are also provided for the addition of diluent and a surfactant into the slurry to control relative permittivity and the electrophoretic mobility of the particles.

Microstrip Cross-coupled Interdigital SIR Based Bandpass Filter

Directory of Open Access Journals (Sweden)

R. K. Maharjan

2012-09-01

Full Text Available A simple and compact 4.9 GHz bandpass filter for C-band applications is proposed. This paper presents a novel microstrip cross-coupled interdigital half-wavelength stepped impedance resonator (SIR based bandpass filter (BPF.The designed structure is similar to that of a combination of two parallel interdigital capacitors. The scattering parameters of the structure are measured using vector network analyzer (VNA. The self generated capacitive and inductive reactances within the interdigital resonators exhibited in a resonance frequency of 4.9 GHz. The resonant frequency and bandwidth of the capacitive cross-coupled resonator is directly optimized from the physical arrangement of the resonators. The measured insertion loss (S21 and return loss (S11 were 0.3 dB and 28 dB, respectively, at resonance frequency which were almost close to the simulation results.

CrossFlow: Cross-Organizational Workflow Management in Dynamic Virtual Enterprises

NARCIS (Netherlands)

Grefen, P.W.P.J.; Aberer, Karl; Hoffner, Yigal; Ludwig, Heiko

In this report, we present the approach to cross-organizational workflow management of the CrossFlow project. CrossFlow is a European research project aiming at the support of cross-organizational workflows in dynamic virtual enterprises. The cooperation in these virtual enterprises is based on

CrossFlow : cross-organizational workflow management in dynamic virtual enterprises

NARCIS (Netherlands)

Grefen, P.W.P.J.; Aberer, K.; Hoffner, Y.

2000-01-01

This paper gives a detailed overview of the approach to cross-organizational workflow management developed in the CrossFlow project. CrossFlow is a European research project aiming at the support of cross-organizational workflows in dynamic virtual enterprises. The cooperation in these virtual

Zero-crossing detection algorithm for arrays of optical spatial filtering velocimetry sensors

DEFF Research Database (Denmark)

Jakobsen, Michael Linde; Pedersen, Finn; Hanson, Steen Grüner

2008-01-01

This paper presents a zero-crossing detection algorithm for arrays of compact low-cost optical sensors based on spatial filtering for measuring fluctuations in angular velocity of rotating solid structures. The algorithm is applicable for signals with moderate signal-to-noise ratios, and delivers...... repeating the same measurement error for each revolution of the target, and to gain high performance measurement of angular velocity. The traditional zero-crossing detection is extended by 1) inserting an appropriate band-pass filter before the zero-crossing detection, 2) measuring time periods between zero...

Influence of particulates on crossflow filter performance with tetraphenylborate precipitate

International Nuclear Information System (INIS)

Peterson, R.A.; Nash, C.A.; McCabe, D.J.

1995-01-01

The pretreatment of High Level Waste at the Savannah River Site, prior to vitrification, includes tetraphenylborate precipitation of cesium. Also, strontium and actinides are removed from solution by sorption on monosodium titanate. The resulting slurry is concentrated and washed using 0.4 micron stainless steel Mott filters in a crossflow assembly. The rate of filtrate production is governed by a number of parameters including the concentration of both soluble and insoluble solids present in the process stream. The major insoluble constituents in the process stream are tetraphenylborate solids. However, the presence of small quantities of monosodium titanate as well as sludge particulates, typically less than 10% of the total solids concentration, produces up to a 50% decline in the rate of filtrate production. The cake that develops during filtration is the primary resistance to flow of filtrate. In addition, experimental data indicate the filter cake is enriched in the insoluble solids relative to the bulk of the solution. The presence of these insoluble solids in the filter cake influences not only the overall filtrate flow rate, but also the mechanisms by which the filter cake is formed

Prestart-up hydrogen peroxide solution washing of NPP unit with the RBMK-type reactor

International Nuclear Information System (INIS)

Gruzdev, N.I.; Man'kina, N.N.; Al'tshuller, M.A.

1979-01-01

Presented are the results of industrial hydrogen peroxide solution washing of condensating-feed system conducted on the second unit of the Kursk NPP. Duration of the washing constituted 8 hours. The hydrogen peroxide concentration during first 4 hours was 10-20 mg/kg at a flow rate of 260 m 2 /h, during the following 4 hours it constituted 2-5 mg/kg at a flow rate of 1000 m 3 /h. It is found out that prestart-up hydrogen peroxide washing of NPP power units with the RBMK-type reactor permits: to simplify essentially the technology and scheme of washing process; to reduce a flow rate of desalt washing water; to except environmental contamination with washing solutions and reagents being neutralized; to reduce the time of washing process; to reduce the time necessary for the achievement of reference water condition factors, and to increase the unit reliability and to improve a radiation situation

CFD simulation of an internal spin-filter: evidence of lateral migration and exchange flow through the mesh.

Science.gov (United States)

Figueredo-Cardero, Alvio; Chico, Ernesto; Castilho, Leda R; Medronho, Ricardo A

2009-11-01

In the present work Computational Fluid Dynamics (CFD) was used to study the flow field and particle dynamics in an internal spin-filter (SF) bioreactor system. Evidence of a radial exchange flow through the filter mesh was detected, with a magnitude up to 130-fold higher than the perfusion flow, thus significantly contributing to radial drag. The exchange flow magnitude was significantly influenced by the filter rotation rate, but not by the perfusion flow, within the ranges evaluated. Previous reports had only given indirect evidences of this exchange flow phenomenon in spin-filters, but the current simulations were able to quantify and explain it. Flow pattern inside the spin-filter bioreactor resembled a typical Taylor-Couette flow, with vortices being formed in the annular gap and eventually penetrating the internal volume of the filter, thus being the probable reason for the significant exchange flow observed. The simulations also showed that cells become depleted in the vicinity of the mesh due to lateral particle migration. Cell concentration near the filter was approximately 50% of the bulk concentration, explaining why cell separation achieved in SFs is not solely due to size exclusion. The results presented indicate the power of CFD techniques to study and better understand spin-filter systems, aiming at the establishment of effective design, operation and scale-up criteria.

Membrane processes for the reuse of car washing wastewater

Directory of Open Access Journals (Sweden)

Deniz Uçar

2018-04-01

Full Text Available This study investigates alternative treatments of car wash effluents. The car wash wastewater was treated by settling, filtration, and membrane filtration processes. During settling, total solid concentration decreased rapidly within the first 2 hours and then remained constant. Chemical oxygen demand (COD and conductivity were decreased by 10% and 4%, respectively. After settling, wastewater was filtered throughout a 100 μm filter. It was found that filtration had a negligible effect on COD removal. Finally, wastewater was filtered by four ultrafiltration membranes of varying molecular weight cutoff (MWCO (1, 5, 10 and 50 kDa and one nanofiltration membrane (NF270, MWCO = 200–400 Da. The permeate COD concentrations varied between 64.5 ± 3.2 and 85.5 ± 4.3 mg L−1 depending on UF pore size. When the NF270 nanofiltration membrane was used, the permeate COD concentration was 8.1 ± 0.4 mg L−1 corresponding to 97% removal. FeCl3 precipitation and activated carbon adsorption techniques were also applied to the retentate and 60–76% COD removals were obtained for activated carbon adsorption and FeCl3 precipitation, respectively.

A wash fluid for drilling into a field

Energy Technology Data Exchange (ETDEWEB)

Belyakov, V M; Badzhurak, R F; Koptelova, Ye K; Rogovoy, V K; Sapozhnikov, N G

1979-01-18

A wash fluid is proposed, used in drilling wells in water and a content of 3-5% by weight starch products. To speed up destruction of the starch products, to the fluid are added amylolytic enzymes in the amount of 0.01-0.1 percent by weight of the starch products' weight. To lower the use of starch products, up to 3% clay can be added to the fluid. The wash fluid is prepared directly at the work site. Dry powder of modified starch is mixed with cold water until a colloidal solution is obtained. Such a wash fluid preserves the required structural-mechanical properties for 3-5 days, which ensures prompt drilling into the waterbearing layer and installation of the filter. Then, during the work process, 5-6 hours before the moment required for lowering the viscosity, to the wash fluid is added the amylolytic enzyme; under its influence, the starch molecules split up, and the viscosity drops sharply. Using this wash fluid enables a reduction in well construction times from the beginning of drilling to the end of development of the water-bearing layer, and a rise in outputs and well service lives by reducing sedimentation of the water-bearing formation and elimination of down times during work required while waiting for destruction of the starch wash fluid under natural conditions.

[Design Method Analysis and Performance Comparison of Wall Filter for Ultrasound Color Flow Imaging].

Science.gov (United States)

Wang, Lutao; Xiao, Jun; Chai, Hua

2015-08-01

The successful suppression of clutter arising from stationary or slowly moving tissue is one of the key issues in medical ultrasound color blood imaging. Remaining clutter may cause bias in the mean blood frequency estimation and results in a potentially misleading description of blood-flow. In this paper, based on the principle of general wall-filter, the design process of three classes of filters, infinitely impulse response with projection initialization (Prj-IIR), polynomials regression (Pol-Reg), and eigen-based filters are previewed and analyzed. The performance of the filters was assessed by calculating the bias and variance of a mean blood velocity using a standard autocorrelation estimator. Simulation results show that the performance of Pol-Reg filter is similar to Prj-IIR filters. Both of them can offer accurate estimation of mean blood flow speed under steady clutter conditions, and the clutter rejection ability can be enhanced by increasing the ensemble size of Doppler vector. Eigen-based filters can effectively remove the non-stationary clutter component, and further improve the estimation accuracy for low speed blood flow signals. There is also no significant increase in computation complexity for eigen-based filters when the ensemble size is less than 10.

Lattice Boltzmann simulations for wall-flow dynamics in porous ceramic diesel particulate filters

Science.gov (United States)

Lee, Da Young; Lee, Gi Wook; Yoon, Kyu; Chun, Byoungjin; Jung, Hyun Wook

2018-01-01

Flows through porous filter walls of wall-flow diesel particulate filter are investigated using the lattice Boltzmann method (LBM). The microscopic model of the realistic filter wall is represented by randomly overlapped arrays of solid spheres. The LB simulation results are first validated by comparison to those from previous hydrodynamic theories and constitutive models for flows in porous media with simple regular and random solid-wall configurations. We demonstrate that the newly designed randomly overlapped array structures of porous walls allow reliable and accurate simulations for the porous wall-flow dynamics in a wide range of solid volume fractions from 0.01 to about 0.8, which is beyond the maximum random packing limit of 0.625. The permeable performance of porous media is scrutinized by changing the solid volume fraction and particle Reynolds number using Darcy's law and Forchheimer's extension in the laminar flow region.

Soil washing: From characterization to implementation

International Nuclear Information System (INIS)

Corden, F.L.; Groenendijk, E.

1995-01-01

Only recently has soil washing begun to be applied to remediation of contaminated soils in the US. The experience gained during full-scale and large pilot-scale projects points to the importance of soil and site characterization in correctly evaluating the applicability of soil washing to a site and determining accurate cost estimates for its implementation. This paper will discuss actual case studies of various treatability and pilot study approaches that led to successful evaluation and implementation of soil washing remedies. Soil washing is applicable to a broad variety of chemical contaminants. Target contaminants include metals, radionuclides, pesticides, polychlorinated biphenyls, polynuclear aromatic hydrocarbons and petroleum hydrocarbons, as well as combinations of these contaminants. Because the contaminants noted above are deposited in the soils in a variety of forms, the unit operations necessary to treat the soil vary. It is the diversity of the available treatment alternatives, and the ability to use the units in a variety of process flow configurations that result in a very broad definition of soil washing

Efficient simulations of fluid flow coupled with poroelastic deformations in pleated filters

KAUST Repository

Calo, Victor M.

2015-04-27

Pleated filters are broadly used for various applications. In certain cases, especially in solid-liquid separation case, the filtering media may get deflected and that may change the overall performance characteristics of the filter. From the modeling point of view, this is a challenging multiphysics problem, namely the interaction of the fluid with a so-called poroelastic structure. This work focuses on the development of an algorithm for the simulation of the Fluid Porous Structure Interaction (FPSI) problem in the case of pleated filtering media. The first part of the work is concerned with the development of a robust and accurate numerical method for solving the Stokes-Brinkman system of equations on quadrilateral grids. The mathematical model describes a free fluid flow coupled with a flow in porous media in a domain that contains the filtering media. To discretize the complex computational domain we use quadrilateral boundary fitted grids which resolve porous-fluid interfaces. The Stokes-Brinkman system of equations is discretized here using a sophisticated finite volume method, namely multi-point flux approximation (MPFA) O-method. MPFA is widely used, e.g., in solving scalar elliptic equations with full tensor and highly varying coefficients and/or solving on heterogeneous non-orthogonalgrids. Up to the authors’ knowledge, there was no investigation of MPFA discretization for Stokes-Brinkman problems, and this study aims to fill this gap. Some numerical experiments are presented in order to demonstrate the robustness of the proposed numerical algorithm[1]. The second part of this study focuses on the coupling of the flow model with the deflection of the filtering media. For the consideration of the FPSI problem in 3D, the classical Biot system describes coupled flow and deformations in a porous body due to difference in the upstream and downstream pressures. Solving the Biot system of equations is complicated and requires a significant amount of

Enhanced salmonella reduction on tomatoes washed in chlorinated water with wash aid T-128

Science.gov (United States)

Chlorine is widely used by the fresh and fresh-cut produce industries to reduce microbial populations and to prevent potential pathogen cross contamination during produce washing. However, the organic materials released from produce quickly react with chlorine and degrade its efficacy for pathogen i...

Use of pulsed neutron logging to evaluate perforation washing

International Nuclear Information System (INIS)

Dimon, C.A.

1986-01-01

This invention relates to the use of pulsed neutron logging techniques before and after perforation washing operations are performed to evaluate the degree of success of the perforation washing operations. Well logging operations of a type designed to respond to the difference between a formation immediately behind the well sheath and voids in the formation are performed both before and after the perforation washing operation. differences between the two resulting logs are then indicative of voids created by perforation washing. In a preferred embodiment, pulsed neutron logging is used as the logging technique, while a weighted brine having a high absorption cross section to pulsed neutrons is used as the perforation washing fluid

A new approach involving a multi transducer ultrasonic system for cleaning turbine engines' oil filters under practical conditions.

Science.gov (United States)

Nguyen, Dinh Duc; Ngo, Huu Hao; Yoon, Yong Soo; Chang, Soon Woong; Bui, Hong Ha

2016-09-01

The purpose of this paper is to provide a green technology that can clean turbine engine oil filters effectively in ships using ultrasound, with ultrasonic devices having a frequency of 25kHz and different powers of 300W and 600W, respectively. The effects of temperature, ultrasonic cleaning times, pressure losses through the oil filter, solvent washing, and ultrasonic power devices were investigated. In addition, the cleaning efficiency of three modes (hand washing, preliminary washing and ultrasonic washing) were compared to assess their relative effectiveness. Experimental results revealed that the necessary ultrasonic time varied significantly depending on which solvent was used for washing. For instance, the optimum ultrasonic cleaning time was 50-60min when the oil filter was cleaned in a solvent of kerosene oil (KO) and over 80min when in a solvent of diesel oil (DO) using the same ultrasonic generator device (25kHz, 600W) and experimental conditions. Furthermore, microscopic examination did not reveal any damage or breakdown on or within the structure of the filter after ultrasonic cleaning, even in the filter's surfaces at a constantly low frequency of 25kHz and power specific capacity (100W/gal). Overall, it may be concluded that ultrasound-assisted oil filter washing is effective, requiring a significantly shorter time than manual washing. This ultrasonic method also shows promise as a green technology for washing oil filters in turbine engines in general and Vietnamese navy ships in particular, because of its high cleaning efficiency, operational simplicity and savings. Copyright © 2016 Elsevier B.V. All rights reserved.

Geopolymerisation of silt generated from construction and demolition waste washing plants.

Science.gov (United States)

Lampris, C; Lupo, R; Cheeseman, C R

2009-01-01

Recycling plants that size, sort and wash construction and demolition waste can produce high quality aggregate. However, they also produce up to 80ton per hour of filter cake waste containing fine (waste and normally landfilled. This research investigated the potential to form geopolymers containing silt, which would allow this problematic waste to be beneficially reused as aggregate. This would significantly improve the economic viability of recycling plants that wash wastes. Silt filter cakes have been collected from a number of aggregate washing plants operating in the UK. These were found to contain similar aluminosilicate crystalline phases. Geopolymer samples were produced using silt and silt mixed with either metakaolin or pulverised fuel ash (PFA). Silt geopolymers cured at room temperature had average 7-day compressive strengths of 18.7MPa, while partial substitution of silt by metakaolin or PFA increased average compressive strengths to 30.5 and 21.9MPa, respectively. Curing specimens for 24h at 105 degrees C resulted in a compressive strength of 39.7MPa and microstructural analysis confirmed the formation of dense materials. These strengths are in excess of those required for materials to be used as aggregate, particularly in unbound applications. The implications of this research for the management of waste silt at construction and demolition waste washing plants are discussed.

Experimental research on the flow field uniformity in the filter house of a nuclear air cleaning system

International Nuclear Information System (INIS)

Jiang Feng; Yang Jun; Ye Suisheng

2000-01-01

The filter house structure is designed using similarity laws showing that the filter house structure causes a non-uniform flow field. The flow field is also measured experimentally. The air flow field is analyzed for different conditions. The results show that: (1) The HEPA filters affect the dispersion of the air flow; (2) The appropriate angle for air input to the rectifier satisfies the requirements for uniform air flow for the test conditions; (3) The rectifier has little influence on the air flow for operating conditions

Investigation Of Cross-Flow Model Water Turbine

International Nuclear Information System (INIS)

Obretenov, V.S.

1998-01-01

The research is made with the basic objective of constructing effective stream section of cross-flow turbine. In the research project are presented the results from experimental testing of the cross-flow turbine with various runner. nozzles and draft tubes. The rotational and universal characteristics of the turbine are presented. The experimental results have been analyzed.The results from the research give the possibility to make clear some important aspects of the working process with the cross-flow turbines. The characteristics derived from these tests prove that the stream section of the tested cross-flow turbine can be used as a model in the construction of cross-flow turbines for power electric stations with small capacity

Characterization of the selectivity of microsieves using a cross-flow microfiltration system

Directory of Open Access Journals (Sweden)

L. E. Gutierrez-Rivera

2010-12-01

Full Text Available Filtration through membranes is a process largely employed in the food and chemical industry to separate particles. Sieves present some advantages in relation to conventional membranes such as high homogeneity in the pore sizes, smooth surfaces, straight-through pores, etc. In this paper we compare the selectivity in the exclusion of particles by size of sieves with circular and slit pores with the same porosity. The selectivity was investigated by filtering a mixture of rutin in water in a cross-flow filtration system. The particle-size distribution of the rutin solution was measured before and after microfiltration. The results showed a high efficiency in the size exclusion of particles for microsieves with circular pores. The filtration through a commercial membrane (net filter with similar characteristics was also characterized for comparison.

Water saving in IC wafer washing process; IC wafer senjo deno sessui taisaku

Energy Technology Data Exchange (ETDEWEB)

Harada, H. [Mitsubishi Corp., Tokyo (Japan); Araki, M.; Nakazawa, T.

1997-11-30

This paper reports features of a wafer washing technology, a new IC wafer washing process, its pure water saving effect, and a `QC washing` which has pure water saving effect in the wafer washing. Wafer washing processes generally include the SC1 process (using ammonia + hydrogen peroxide aqueous solution) purposed for removing contamination due to ultrafine particles, the SC2 process (using hydrochloric acid + hydrogen peroxide aqueous solution) purposed for removing contamination due to heavy metals, the piranha washing process (using hot sulfuric acid + hydrogen peroxide aqueous solution) purposed for removing contamination due to organic matters, and the DHF (using dilute hydrofluoric acid) purposed for removing natural oxide films. Natural oxide films are now remained as surface protection films, by which surface contamination has been reduced remarkably. A high-temperature washing chemical circulating and filtering technology developed in Japan has brought about a reform in wafer washing processes having been used previously. Spin washing is used as a water saving measure, in which washing chemicals or pure water are sprayed onto one each of wafers which is spin-rotated, allowing washing and rinsing to be made with small amount of washing chemicals and pure water. The QC washing is a method to replace tank interior with pure was as quick as possible in order to increase the rinsing effect. 7 refs., 5 figs.

Cross-flow-assembled ultrathin and robust graphene oxide membranes for efficient molecule separation

Science.gov (United States)

Ying, Yulong; Ying, Wen; Guo, Yi; Peng, Xinsheng

2018-04-01

A graphene oxide (GO) membrane is promising for molecule separation. However, it is still a big challenge to achieve highly stable pristine GO membranes, especially in water. In this work, an ultrathin and robust GO membrane is assembled via the cross-flow method. The as-prepared 12 nm thick GO membrane (GOCF membrane) presents high stability with water permeance of 1505 ± 65 litres per hour per square meter per bar (LHM bar-1) and Evans Blue (EB) rejection of 98.7 ± 0.4%, 21-fold enhancement in water permeance compared with that of a pristine GO membrane (50-70 LHM bar-1) and 100 times higher than that of commercial ultrafiltration membranes (15 LHM.bar-1, GE2540F30, MWCO 1000, GE Co., Ltd) with similar rejection. Attributed to the surface cross-flow, the GO nanosheets will be refolded, crumpled, or wrinkled, resulting in a very strong inter-locking structure among the GO membrane, which significantly enhances the stability and facilitates their separation performance. This cross-flow assembling technique is also easily extended to assemble GO membranes onto other various backing filter supports. Based on the Donnan effect and size sieving mechanism, selective membrane separation of dyes with a similar molecular structure from their mixture (such as Rhodamine B (RhB) and Rose Bengal, and RhB and EB) are achieved with a selectivity of 133 ± 10 and 227 ± 15, respectively. Assembly of this ultrathin GO membrane with high stability and separation performance, via a simple cross-flow method, shows great potential for water purification.

Fabrication of antibacterial water filter by coating silver nanoparticles on flexible polyurethane foams

International Nuclear Information System (INIS)

Nguyen Thi Phuong Phong; Ngo Vo Ke Thanh; Phan Hue Phuong

2009-01-01

In this paper, we fabricated silver-coated polyurethane foams and used it as a bacterial filter for contaminated drinking water. Flexible PU foams were soaked in silver colloidal solutions for 10 h, then washed and air-dried at room temperature. The prepared silver colloidal solutions and silver-coated PU materials were characterized by several techniques including TEM, FESEM/EDS, UV-VIS, ICP-AAS, and Raman spectroscopy. The TEM images showed that the size of silver nanoparticles in colloidal solutions varies from 6 to 12nm. The Raman, FE-SEM/EDS and ICP-AAS data illustrated that silver nanoparticles were stable on the PU foam and were not washed away by water. Furthermore, the microbiological tests (tube tests and flow test) were carried out on silver-coated PU materials with the Coliforms, E. coli, and B. subtilis. The obtained results showed that the bacteria was killed completely with antibacterial efficiency of 100% being observed. Our research suggests that silver-coated polyurethane foams can be used as excellent antibacterial water filters and would have several applications in other sectors.

Desflurane usage during anesthesia with and without N2O using FLOW-i Automatic Gas Control with three different wash-in speeds.

Science.gov (United States)

De Medts, Robrecht; Carette, Rik; De Wolf, Andre M; Hendrickx, Jan F A

2017-06-09

AGC ® (Automatic Gas Control) is the FLOW-i's automated low flow tool (Maquet, Solna, Sweden) that target controls the inspired O 2 (F I O 2 ) and end-expired desflurane concentration (F A des) while (by design) exponentially decreasing fresh gas flow (FGF) during wash-in to a maintenance default FGF of 300 mL min -1 . It also offers a choice of wash-in speeds for the inhaled agents. We examined AGC performance and hypothesized that the use of lower wash-in speeds and N 2 O both reduce desflurane usage (Vdes). After obtaining IRB approval and patient consent, 78 ASA I-II patients undergoing abdominal surgery were randomly assigned to 1 of 6 groups (n = 13 each), depending on carrier gas (O 2 /air or O 2 /N 2 O) and wash-in speed (AGC speed 2, 4, or 6) of desflurane, resulting in groups air/2, air/4, air/6, N 2 O/2, N 2 O/4, and N 2 O/6. The target for F I O 2 was set at 35%, while the F A des target was selected so that the AGC displayed 1.3 MAC (corrected for the additive affect of N 2 O if used). AGC was activated upon starting mechanical ventilation. Varvel's criteria were used to describe performance of achieving the targets. Patient demographics, end-expired N 2 O concentration, MAC, FGF, and Vdes were compared using ANOVA. Data are presented as mean ± standard deviation, except for Varvel's criteria (median ± quartiles). Patient demographics did not differ among the groups. Median performance error was -2-0% for F I O 2 and -3-1% for F A des; median absolute performance error was 1-2% for F I O 2 and 0-3% for F A des. MAC increased faster in N 2 O groups, but total MAC decreased 0.1-0.25 MAC below that in the O 2 /air groups after 60 min. The effect of wash-in speed on Vdes faded over time. N 2 O decreased Vdes by 62%. AGC performance for O 2 and desflurane targeting is excellent. After 1 h, the wash-in speeds tested are unlikely to affect desflurane usage. N 2 O usage decreases Vdes proportionally with its reduction in F A tdes.

Filters for radioactive liquid wastes

International Nuclear Information System (INIS)

Koshiba, Yukihiko; Kawashima, Akio

1980-01-01

In the crud generated in the reactor cooling water for nuclear power plants, iron oxides (hematite and magnetite) are contained as the main components, and also Co, Mn, Fe, Cr exist as radioactive nuclides. A new filter to separate these cruds, nuclepore membrane filter (NPMF), was investigated for its adaptability, and has been adopted as a practical filter for radioactive liquid wastes. The NPMF has such features as the possibility of complete automation of operation, no generation of secondary wastes, and easy maintenance, because the NPMF has uniform circular holes in poly-carbonate thin films, and shows the properties of stable filtering of particulates, capability of back washing, and others. The elements mounted in a practical system have such construction that the membrane is cut in the form of doughnut, and sandwiched with 100 mesh polyester nets (spacer); the obtained unit filter (cassette) is mounted on the stackable plate of the same size; and 80 pieces of this cassette are formed in a filter of 4 m 2 filtering area. The performance varies with the properties of suspended matters and the turbidity of wastes. For example, the filtered liquid of 0.1 ppm or less can be obtained when the 1 μm filter material is used to treat the liquid waste containing 1 to 100 ppm suspended matters. Usually back washed water is produced by about 1/100 of treated liquid wastes. The lifetime of the membrane is expected to be 1 or 2 years if crud is the main component. (Wakatsuki, Y.)

Aerosol filtration with metallic fibrous filters

International Nuclear Information System (INIS)

Klein, M.; Goossens, W.R.A.

1983-01-01

The filtration efficiency of stainless steel fibrous filters (BEKIPOR porous mats and sintered webs) is determined using submicronic monodisperse polystyrene aerosols. Lasers spectrometers are used for the aerosol measurements. The parameters varied are the fiber diameter, the number of layers, the aerosol diameter and the superficial velocity. Two selected types of filters are tested with polydisperse methylene blue aerosols to determine the effect of bed loading on the filter performance and to test washing techniques for the regeneration of the filter

Performance evaluation of a dual-flow recharge filter for improving groundwater quality.

Science.gov (United States)

Samuel, Manoj P; Senthilvel, S; Mathew, Abraham C

2014-07-01

A dual-flow multimedia stormwater filter integrated with a groundwater recharge system was developed and tested for hydraulic efficiency and pollutant removal efficiency. The influent stormwater first flows horizontally through the circular layers of planted grass and biofibers. Subsequently, the flow direction changes to a vertical direction so that water moves through layers of pebbles and sand and finally gets recharged to the deep aquifers. The media in the sequence of vegetative medium:biofiber to pebble:sand were filled in nine proportions and tested for the best performing combination. Three grass species, viz., Typha (Typha angustifolia), Vetiver (Chrysopogon zizanioides), and St. Augustine grass (Stenotaphrum secundatum), were tested as the best performing vegetative medium. The adsorption behavior of Coconut (Cocos nucifera) fiber, which was filled in the middle layer, was determined by a series of column and batch studies.The dual-flow filter showed an increasing trend in hydraulic efficiency with an increase in flowrate. The chemical removal efficiency of the recharge dual-flow filter was found to be very high in case of K+ (81.6%) and Na+ (77.55%). The pH normalizing efficiency and electrical conductivity reduction efficiency were also recorded as high. The average removal percentage of Ca2+ was moderate, while that of Mg2+ was very low. The filter proportions of 1:1 to 1:2 (plant:fiber to pebble:sand) showed a superior performance compared to all other proportions. Based on the estimated annual costs and returns, all the financial viability criteria (internal rate of return, net present value, and benefit-cost ratio) were found to be favorable and affordable to farmers in terms of investing in the developed filtration system.

Cross-correlated imaging of distributed mode filtering rod fiber

DEFF Research Database (Denmark)

Laurila, Marko; Barankov, Roman; Jørgensen, Mette Marie

2013-01-01

We analyze the modal properties of an 85μm core distributed mode filtering rod fiber using cross-correlated (C2) imaging. We evaluate suppression of higher-order modes (HOMs) under severely misaligned mode excitation and identify a single-mode regime where HOMs are suppressed by more than 20dB....

Efficient simulations of fluid flow coupled with poroelastic deformations in pleated filters

KAUST Repository

Calo, Victor M.; Iliev, Dimitar; Iliev, Oleg; Kirsch, Ralf; Lakdawala, Zahra; Printsypar, Galina

2015-01-01

model describes a free fluid flow coupled with a flow in porous media in a domain that contains the filtering media. To discretize the complex computational domain we use quadrilateral boundary fitted grids which resolve porous-fluid interfaces

Computational fluid dynamics simulations of single-phase flow in a filter-press flow reactor having a stack of three cells

International Nuclear Information System (INIS)

Sandoval, Miguel A.; Fuentes, Rosalba; Walsh, Frank C.; Nava, José L.; Ponce de León, Carlos

2016-01-01

Highlights: • Computational fluid dynamic simulations in a filter-press stack of three cells. • The fluid velocity was different in each cell due to local turbulence. • The upper cell link pipe of the filter press cell acts as a fluid mixer. • The fluid behaviour tends towards a continuous mixing flow pattern. • Close agreement between simulations and experimental data was achieved. - Abstract: Computational fluid dynamics (CFD) simulations were carried out for single-phase flow in a pre-pilot filter press flow reactor with a stack of three cells. Velocity profiles and streamlines were obtained by solving the Reynolds-Averaged Navier-Stokes (RANS) equations with a standard k − ε turbulence model. The flow behaviour shows the appearance of jet flow at the entrance to each cell. At lengths from 12 to 15 cm along the cells channels, a plug flow pattern is developed at all mean linear flow rates studied here, 1.2 ≤ u ≤ 2.1 cm s −1 . The magnitude of the velocity profiles in each cell was different, due to the turbulence generated by the change of flow direction in the last fluid manifold. Residence time distribution (RTD) simulations indicated that the fluid behaviour tends towards a continuous mixing flow pattern, owing to flow at the output of each cell across the upper cell link pipe, which acts as a mixer. Close agreement between simulations and experimental RTD was obtained.

Construction of low dissipative high-order well-balanced filter schemes for non-equilibrium flows

International Nuclear Information System (INIS)

Wang Wei; Yee, H.C.; Sjoegreen, Bjoern; Magin, Thierry; Shu, Chi-Wang

2011-01-01

The goal of this paper is to generalize the well-balanced approach for non-equilibrium flow studied by Wang et al. (2009) to a class of low dissipative high-order shock-capturing filter schemes and to explore more advantages of well-balanced schemes in reacting flows. More general 1D and 2D reacting flow models and new examples of shock turbulence interactions are provided to demonstrate the advantage of well-balanced schemes. The class of filter schemes developed by Yee et al. (1999) , Sjoegreen and Yee (2004) and Yee and Sjoegreen (2007) consist of two steps, a full time step of spatially high-order non-dissipative base scheme and an adaptive non-linear filter containing shock-capturing dissipation. A good property of the filter scheme is that the base scheme and the filter are stand-alone modules in designing. Therefore, the idea of designing a well-balanced filter scheme is straightforward, i.e. choosing a well-balanced base scheme with a well-balanced filter (both with high-order accuracy). A typical class of these schemes shown in this paper is the high-order central difference schemes/predictor-corrector (PC) schemes with a high-order well-balanced WENO filter. The new filter scheme with the well-balanced property will gather the features of both filter methods and well-balanced properties: it can preserve certain steady-state solutions exactly; it is able to capture small perturbations, e.g. turbulence fluctuations; and it adaptively controls numerical dissipation. Thus it shows high accuracy, efficiency and stability in shock/turbulence interactions. Numerical examples containing 1D and 2D smooth problems, 1D stationary contact discontinuity problem and 1D turbulence/shock interactions are included to verify the improved accuracy, in addition to the well-balanced behavior.

Filter material charging apparatus for filter assembly for radioactive contaminants

International Nuclear Information System (INIS)

Goldsmith, J.M.; O'Nan, A. Jr.

1977-01-01

A filter charging apparatus for a filter assembly is described. The filter assembly includes a housing with at least one filter bed therein and the filter charging apparatus for adding filter material to the filter assembly includes a tank with an opening therein, the tank opening being disposed in flow communication with opposed first and second conduit means, the first conduit means being in flow communication with the filter assembly housing and the second conduit means being in flow communication with a blower means. Upon activation of the blower means, the blower means pneumatically conveys the filter material from the tank to the filter housing

CFD Analysis for Predicting Flow Resistance of the Cross Flow Gap in Prismatic VHTR Core

International Nuclear Information System (INIS)

Lee, Jeong Hun; Yoon, Su Jong; Park, Goon Cherl; Park, Jong Woon

2011-01-01

The core of Very High Temperature Reactor (VHTR) consists of assemblies of hexagonal graphite blocks and its height and across-flats width are 800 mm and 360 mm respectively. They are equipped with 108 coolant holes 16 mm in diameter. Up to ten fuel blocks arranged in vertical order form a fuel element column and the neutron flux varies over the cross section of the core. It makes different axial shrinkage of fuel element and this leads to make wedge-shaped gaps between the base and top surfaces of stacked blocks. The cross flow is defined as the core flow that passes through this cross gaps. The cross flow complicates the flow distribution of reactor core. Moreover, the cross flow could lead to uneven coolant distribution and consequently to superheating of individual fuel element zones with increased fission product release. Since the core cross flow has a negative impact on safety and efficiency of VHTR, core cross flow phenomena have to be investigated to improve the core thermal margin of VHTR. In particular, to predict amount of flow at the cross flow gap obtaining accurate flow loss coefficient is important. Nevertheless, there has not been much effort in domestic. The experiment of cross flow was carried out by H. G. Groehn in 1981 Germany. For the study of cross flow the applicability of CFD code should be validated. In this paper a commercial CFD code CFX-12 validation will be carried out with this cross flow experiment. Validated data can be used for validation of other thermal-hydraulic analysis codes

Salmonella transfer during pilot plant scale washing and roller conveying of tomatoes.

Science.gov (United States)

Wang, Haiqiang; Ryser, Elliot T

2014-03-01

Salmonella transfer during washing and roller conveying of inoculated tomatoes was quantified using a pilot scale tomato packing line equipped with plastic, foam, or brush rollers. Red round tomatoes (2.3 kg) were dip inoculated with Salmonella enterica serovar Typhimurium LT2 (avirulent) (4 log CFU/g), air dried for 2 h, and then washed in sanitizer-free water for 2 min. Inoculated tomatoes were then passed single file over a 1.5-m conveyor equipped with plastic, foam, or brush rollers followed by 25 previously washed uninoculated tomatoes. Tomato samples were collected after 2 min of both washing and roller conveying, with all 25 uninoculated tomatoes collected individually after conveying. Roller surface samples were collected before and after conveying the uninoculated tomatoes. Both tomato and surface samples were quantitatively examined for Salmonella by direct plating or membrane filtration using xylose lysine Tergitol 4 agar. Regardless of the roller type, Salmonella populations on inoculated tomatoes did not significantly (P conveyors. After conveying uninoculated tomatoes over contaminated foam rollers, 96% of the 25 tomatoes were cross-contaminated with Salmonella at >100 CFU per tomato. With plastic rollers, 24 and 76% of tomatoes were cross-contaminated with Salmonella at 10 to 100 and 1 to 10 CFU per tomato, respectively. In contrast, only 8% of 25 tomatoes were cross-contaminated with brush rollers with Salmonella populations of 1 to 10 CFU per tomato. Overall, cross-contamination was greatest with foam, followed by plastic and brush rollers (P < 0.05). Adding peroxyacetic acid or chlorine to the wash water significantly decreased cross-contamination during tomato conveying, with chlorine less effective in controlling Salmonella on foam compared with plastic and brush rollers.

Water flow exchange characteristics in coarse granular filter media

DEFF Research Database (Denmark)

Andreasen, Rune Røjgaard; Pugliese, Lorenzo; Poulsen, Tjalfe

2013-01-01

Elution of inhibitory metabolites is a key parameter controlling the efficiency of air cleaning bio- and biotrickling filters. To the authors knowledge no studies have yet considered the relationship between specific surface area related elution velocity and physical media characteristics, which...... in this study are performed at a concurrent airflow of 0.3 m s−1, water irrigation rates of 1–21 cm h−1 in materials with particle diameters ranging from 2 to 14 mm to represent media and operation conditions relevant for low flow biotrickling filter design. Specific surface area related elution velocity...... distribution was closely related to the filter water content, water irrigation rate, media specific surface area and particle size distribution. A predictive model linking the specific surface area related elution velocity distribution to irrigation rate, specific surface area and particle size distribution...

CANFLEX fuel bundle cross-flow endurance test (test report)

International Nuclear Information System (INIS)

Hong, Sung Deok; Chung, C. H.; Chang, S. K.; Kim, B. D.

1997-04-01

As part of the normal refuelling sequence of CANDU nuclear reactor, both new and irradiated bundles can be parked in the cross-flow region of the liner tubes. This situation occurs normally for a few minutes. The fuel bundle which is subjected to the cross-flow should be capable of withstanding the consequences of cross flow for normal periods, and maintain its mechanical integrity. The cross-flow endurance test was conducted for CANFLEX bundle, latest developed nuclear fuel, at CANDU-Hot Test Loop. The test was carried out during 4 hours at the inlet cross-flow region. After the test, the bundle successfully met all acceptance criteria after the 4 hours cross-flow test. (author). 2 refs., 3 tabs

CANFLEX fuel bundle cross-flow endurance test (test report)

Energy Technology Data Exchange (ETDEWEB)

Hong, Sung Deok; Chung, C. H.; Chang, S. K.; Kim, B. D.

1997-04-01

As part of the normal refuelling sequence of CANDU nuclear reactor, both new and irradiated bundles can be parked in the cross-flow region of the liner tubes. This situation occurs normally for a few minutes. The fuel bundle which is subjected to the cross-flow should be capable of withstanding the consequences of cross flow for normal periods, and maintain its mechanical integrity. The cross-flow endurance test was conducted for CANFLEX bundle, latest developed nuclear fuel, at CANDU-Hot Test Loop. The test was carried out during 4 hours at the inlet cross-flow region. After the test, the bundle successfully met all acceptance criteria after the 4 hours cross-flow test. (author). 2 refs., 3 tabs.

Adaptive probabilistic collocation based Kalman filter for unsaturated flow problem

Science.gov (United States)

Man, J.; Li, W.; Zeng, L.; Wu, L.

2015-12-01

The ensemble Kalman filter (EnKF) has gained popularity in hydrological data assimilation problems. As a Monte Carlo based method, a relatively large ensemble size is usually required to guarantee the accuracy. As an alternative approach, the probabilistic collocation based Kalman filter (PCKF) employs the Polynomial Chaos to approximate the original system. In this way, the sampling error can be reduced. However, PCKF suffers from the so called "cure of dimensionality". When the system nonlinearity is strong and number of parameters is large, PCKF is even more computationally expensive than EnKF. Motivated by recent developments in uncertainty quantification, we propose a restart adaptive probabilistic collocation based Kalman filter (RAPCKF) for data assimilation in unsaturated flow problem. During the implementation of RAPCKF, the important parameters are identified and active PCE basis functions are adaptively selected. The "restart" technology is used to alleviate the inconsistency between model parameters and states. The performance of RAPCKF is tested by unsaturated flow numerical cases. It is shown that RAPCKF is more efficient than EnKF with the same computational cost. Compared with the traditional PCKF, the RAPCKF is more applicable in strongly nonlinear and high dimensional problems.

Adaptive Rate Sampling and Filtering Based on Level Crossing Sampling

Directory of Open Access Journals (Sweden)

Saeed Mian Qaisar

2009-01-01

Full Text Available The recent sophistications in areas of mobile systems and sensor networks demand more and more processing resources. In order to maintain the system autonomy, energy saving is becoming one of the most difficult industrial challenges, in mobile computing. Most of efforts to achieve this goal are focused on improving the embedded systems design and the battery technology, but very few studies target to exploit the input signal time-varying nature. This paper aims to achieve power efficiency by intelligently adapting the processing activity to the input signal local characteristics. It is done by completely rethinking the processing chain, by adopting a non conventional sampling scheme and adaptive rate filtering. The proposed approach, based on the LCSS (Level Crossing Sampling Scheme presents two filtering techniques, able to adapt their sampling rate and filter order by online analyzing the input signal variations. Indeed, the principle is to intelligently exploit the signal local characteristics—which is usually never considered—to filter only the relevant signal parts, by employing the relevant order filters. This idea leads towards a drastic gain in the computational efficiency and hence in the processing power when compared to the classical techniques.

Ultrasonic Mastering of Filter Flow and Antifouling of Renewable Resources.

Science.gov (United States)

Radziuk, Darya; Möhwald, Helmuth

2016-04-04

Inadequate access to pure water and sanitation requires new cost-effective, ergonomic methods with less consumption of energy and chemicals, leaving the environment cleaner and sustainable. Among such methods, ultrasound is a unique means to control the physics and chemistry of complex fluids (wastewater) with excellent performance regarding mass transfer, cleaning, and disinfection. In membrane filtration processes, it overcomes diffusion limits and can accelerate the fluid flow towards the filter preventing antifouling. Here, we outline the current state of knowledge and technological design, with a focus on physicochemical strategies of ultrasound for water cleaning. We highlight important parameters of ultrasound for the delivery of a fluid flow from a technical perspective employing principles of physics and chemistry. By introducing various ultrasonic methods, involving bubbles or cavitation in combination with external fields, we show advancements in flow acceleration and mass transportation to the filter. In most cases we emphasize the main role of streaming and the impact of cavitation with a perspective to prevent and remove fouling deposits during the flow. We also elaborate on the deficiencies of present technologies and on problems to be solved to achieve a wide-spread application. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Precipitation-filtering technology for uranium waste solution generated on washing-electrokinetic decontamination

Energy Technology Data Exchange (ETDEWEB)

Kim, Gye-Nam, E-mail: kimsum@kaeri.re.kr; Park, Uk-Ryang; Kim, Seung-Soo; Moon, Jei-Kwon

2015-05-15

Graphical abstract: A recycling process diagram for the volume reduction of waste solution generated from washing-electrokinetic decontamination. - Highlights: • A process for recycling a waste solution generated was developed. • The total metal precipitation rate by NaOH in a supernatant after precipitation was the highest at pH 9. • The uranium radioactivity in the treated solution upon injection of 0.2 g of alum was lower. • After drying, the volume of sludge was reduced to 35% of the initial sludge volume. - Abstract: Large volumes of uranium waste solution are generated during the operation of washing-electrokinetic decontamination equipment used to remove uranium from radioactive soil. A treatment technology for uranium waste solution generated upon washing-electrokinetic decontamination for soil contaminated with uranium has been developed. The results of laboratory-size precipitation experiments were as follows. The total amount of metal precipitation by NaOH for waste solution was highest at pH 11. Ca(II), K(I), and Al(III) ions in the supernatant partially remained after precipitation, whereas the concentration of uranium in the supernatant was below 0.2 ppm. Also, when NaOH was used as a precipitant, the majority of the K(I) ions in the treated solution remained. The problem of CaO is to need a long dissolution time in the precipitation tank, while Ca(OH){sub 2} can save a dissolution time. However, the volume of the waste solution generated when using Ca(OH){sub 2} increased by 8 mL/100 mL (waste solution) compared to that generated when using CaO. NaOH precipitant required lower an injection volume lower than that required for Ca(OH){sub 2} or CaO. When CaO was used as a precipitant, the uranium radioactivity in the treated solution at pH 11 reached its lowest value, compared to values of uranium radioactivity at pH 9 and pH 5. Also, the uranium radioactivity in the treated solution upon injection of 0.2 g of alum with CaO or Ca(OH){sub 2} was

Simulation of flow in the unsaturated zone beneath Pagany Wash, Yucca Mountain

International Nuclear Information System (INIS)

Kwicklis, E.M.; Healy, R.W.; Flint, A.L.

1994-01-01

A one-dimensional numerical model was created to simulate water movement beneath Pagany Wash, Yucca Mountain, Nevada. Model stratigraphy and properties were based on data obtained from boreholes UE-25 UZ No. 4 and UE-25 UZ No. 5, which was drilled in the alluvial channel and bedrock sideslope of Pagany Wash. Although unable to account for multidimensional or preferential flowpaths beneath the wash, the model proved a useful conceptual tool with which to develop hypotheses and, in some cases, provide bounding calculations. The model indicated that liquid flux decreases with depth in the upper 120 m beneath the wash, with fluxes of several tens mm/yr in the nonwelded base of the Tiva Canyon Member and fluxes on the order of a tenth mm/yr in the upper Topopah Spring Member. Capillary barrier effects were indicated by the model to significantly delay the entry of large fluxes into the potential repository horizon during periods of increasing net infiltration, and to inhibit rapid drainage of water from the nonwelded and bedded intervals into the potential repository horizon during periods of moisture redistribution. Lateral moisture redistribution can be expected to be promoted by these effects

High-efficiency particulate air filter behavior at high-speed flows

International Nuclear Information System (INIS)

Tang, P.K.; Gregory, W.S.; Ricketts, C.I.; Smith, P.R.

1984-04-01

This paper presents a filter model based on the principle of fluid flow through porous media. The model includes both laminar and turbulent effects. The coefficients used in the model are determined empirically based on existing data. Deviation from the model is discussed

Modelling of air flows in pleated filters and of their clogging by solid particles

International Nuclear Information System (INIS)

Del Fabbro, L.

2002-01-01

The devices of air cleaning against particles are widely spread in various branches of industry: nuclear, motor, food, electronic,...; among these devices, numerous are constituted by pleated porous media to increase the surface of filtration and thus to reduce the pressure drop, for given air flow. The objective of our work is to compensate a lack evident of knowledge on the evolution of the pressure drop of pleated filter during the clogging and to deduct a modelling from it, on the basis of experiments concerning industrial filters of nuclear and car types. The obtained model is a function of characteristics of the filtering medium and pleats, of the characteristics of solid particles deposited on the filter, of the mass of particles and of the aeraulic conditions of air flow. It also depends on data on the clogging of flat filters of equivalent medium. To elaborate this model of pressure drop, an initial stage was carried out in order to characterize, experimentally and numerically, the pressure drop and the distribution of air flow in clean pleated filters of nuclear (high efficiency particulate air filter, in fiberglasses) and car (mean efficiency filter, in fibers of cellulose) types. The numerical model allowed to understand the fundamental role played by the aeraulic resistance of the filtering medium. From an non-dimensional approach, we established a semi-empirical model of pressure drop for a clean pleated filter valid for both studied types of medium; this model is used of first base for the development of the final model of clogging. The study of the clogging of the filters showed the complexity of the phenomenon dependent mainly on a reduction of the surface of filtration. This observation brings us to propose a clogging of pleated filters in three phases. Both first phases are similar in those observed for flat filters, while last phase corresponds to a reduction of the surface of filtration and leads a strong increase of the filter pressure drop

Coordinated Control of Cross-Flow Turbines

Science.gov (United States)

Strom, Benjamin; Brunton, Steven; Polagye, Brian

2016-11-01

Cross-flow turbines, also known as vertical-axis turbines, have several advantages over axial-flow turbines for a number of applications including urban wind power, high-density arrays, and marine or fluvial currents. By controlling the angular velocity applied to the turbine as a function of angular blade position, we have demonstrated a 79 percent increase in cross-flow turbine efficiency over constant-velocity control. This strategy uses the downhill simplex method to optimize control parameter profiles during operation of a model turbine in a recirculating water flume. This optimization method is extended to a set of two turbines, where the blade motions and position of the downstream turbine are optimized to beneficially interact with the coherent structures in the wake of the upstream turbine. This control scheme has the potential to enable high-density arrays of cross-flow turbines to operate at cost-effective efficiency. Turbine wake and force measurements are analyzed for insight into the effect of a coordinated control strategy.

Construction of Low Dissipative High Order Well-Balanced Filter Schemes for Non-Equilibrium Flows

Science.gov (United States)

Wang, Wei; Yee, H. C.; Sjogreen, Bjorn; Magin, Thierry; Shu, Chi-Wang

2009-01-01

The goal of this paper is to generalize the well-balanced approach for non-equilibrium flow studied by Wang et al. [26] to a class of low dissipative high order shock-capturing filter schemes and to explore more advantages of well-balanced schemes in reacting flows. The class of filter schemes developed by Yee et al. [30], Sjoegreen & Yee [24] and Yee & Sjoegreen [35] consist of two steps, a full time step of spatially high order non-dissipative base scheme and an adaptive nonlinear filter containing shock-capturing dissipation. A good property of the filter scheme is that the base scheme and the filter are stand alone modules in designing. Therefore, the idea of designing a well-balanced filter scheme is straightforward, i.e., choosing a well-balanced base scheme with a well-balanced filter (both with high order). A typical class of these schemes shown in this paper is the high order central difference schemes/predictor-corrector (PC) schemes with a high order well-balanced WENO filter. The new filter scheme with the well-balanced property will gather the features of both filter methods and well-balanced properties: it can preserve certain steady state solutions exactly; it is able to capture small perturbations, e.g., turbulence fluctuations; it adaptively controls numerical dissipation. Thus it shows high accuracy, efficiency and stability in shock/turbulence interactions. Numerical examples containing 1D and 2D smooth problems, 1D stationary contact discontinuity problem and 1D turbulence/shock interactions are included to verify the improved accuracy, in addition to the well-balanced behavior.

A study on the characteristics of the flow distribution in the Module Ceramic Filter during filter cleaning

International Nuclear Information System (INIS)

Chung, Jin-Do; Kim, Jang-Woo; Chung, Hwi-Bok; Im, Byoung-Uk; Chung, Eun-Ho; Yoon, Sang-Wook

2010-01-01

Ceramic filter has demonstrated as an attractive system to improve the efficiency and to reduce the effluent pollutants. Removal of particulates from the hot gas stream is very important in air pollution control. In particular, the elimination of the particulate matters discharged from a gas turbine at high temperature can prevent the corrosion the Integrated Gasification Combined Cycle. In this study, a Lab. scale test and numerical simulation were carried out to comprehend the relationship between pulse jet pressure and recovery of pressure drop and to characterize the reverse cleaning flow through a ceramic filter. (author)

Pleasant/Unpleasant Filtering for Affective Image Retrieval Based on Cross-Correlation of EEG Features

Directory of Open Access Journals (Sweden)

Keranmu Xielifuguli

2014-01-01

Full Text Available People often make decisions based on sensitivity rather than rationality. In the field of biological information processing, methods are available for analyzing biological information directly based on electroencephalogram: EEG to determine the pleasant/unpleasant reactions of users. In this study, we propose a sensitivity filtering technique for discriminating preferences (pleasant/unpleasant for images using a sensitivity image filtering system based on EEG. Using a set of images retrieved by similarity retrieval, we perform the sensitivity-based pleasant/unpleasant classification of images based on the affective features extracted from images with the maximum entropy method: MEM. In the present study, the affective features comprised cross-correlation features obtained from EEGs produced when an individual observed an image. However, it is difficult to measure the EEG when a subject visualizes an unknown image. Thus, we propose a solution where a linear regression method based on canonical correlation is used to estimate the cross-correlation features from image features. Experiments were conducted to evaluate the validity of sensitivity filtering compared with image similarity retrieval methods based on image features. We found that sensitivity filtering using color correlograms was suitable for the classification of preferred images, while sensitivity filtering using local binary patterns was suitable for the classification of unpleasant images. Moreover, sensitivity filtering using local binary patterns for unpleasant images had a 90% success rate. Thus, we conclude that the proposed method is efficient for filtering unpleasant images.

Agricultural sprays in cross-flow and drift

DEFF Research Database (Denmark)

Farooq, M.; Balachandar, R.; Wulfsohn, Dvoralai

2001-01-01

The droplet size and velocity characteristics of an agricultural spray were studied in a wind tunnel in the presence of a non-uniform cross-flow. The spray was generated at three nozzle-operating pressures. The droplet size and velocity was measured in both the cross-flow direction and the vertical...

Domestic wash water reclamation for reuse as commode water supply using filtration: Reverse-osmosis separation technique

Science.gov (United States)

Hall, J. B., Jr.; Batten, C. E.; Wilkins, J. R.

1974-01-01

A combined filtration-reverse-osmosis water recovery system has been evaluated to determine its capability to reclaim domestic wash water for reuse as a commode water supply. The system produced water that met all chemical and physical requirements established by the U.S. Public Health Service for drinking water with the exception of carbon chloroform extractables, methylene blue active substances, and phenols. It is thought that this water is of sufficient quality to be reused as commode supply water. The feasibility of using a combined filtration and reverse-osmosis technique for reclaiming domestic wash water has been established. The use of such a technique for wash-water recovery will require a maintenance filter to remove solid materials including those less than 1 micron in size from the wash water. The reverse-osmosis module, if sufficiently protected from plugging, is an attractive low-energy technique for removing contaminants from domestic wash water.

The flows structure in unsteady gas flow in pipes with different cross-sections

OpenAIRE

Plotnikov Leonid; Nevolin Alexandr; Nikolaev Dmitrij

2017-01-01

The results of numerical simulation and experimental study of the structure of unsteady flows in pipes with different cross sections are presented in the article. It is shown that the unsteady gas flow in a circular pipe is axisymmetric without secondary currents. Steady vortex structures (secondary flows) are observed in pipes with cross sections in the form of a square and an equilateral triangle. It was found that these secondary flows have a significant impact on gas flows in pipes of com...

Pyrolytic graphite as an efficient second-order neutron filter at tuned positions of boundary crossing

International Nuclear Information System (INIS)

Adib, M.; Abdel Kawy, A.; Habib, N.; El Mesiry, M.

2010-01-01

An investigation of pyrolytic graphite (PG) crystal as an efficient second order neutron filter at tuned boundary crossings has been carried out. The neutron transmission through PG crystal at these tuned crossing points as a function of first- and second-order wavelengths were calculated in terms of PG mosaic spread and thickness. The filtering features of PG crystals at these tuned boundary crossings were deduced. It was shown that, there are a large number of tuned positions at double and triple boundary crossings of the curves (hkl) are very promising as tuned filter positions. However, only fourteen of them are found to be most promising ones. These tuned positions are found to be within the neutron wavelengths from 0.133 up to 0.4050 nm. A computer package GRAPHITE has been used in order to provide the required calculations in the whole neutron wavelength range in terms of PG mosaic spread and its orientation with respect to incident neutron beam direction. It was shown that 0.5 cm thick PG crystal with angular mosaic spread of 2 0 is sufficient to remove 2nd-order neutrons at the wavelengths corresponding to the positions of the intersection boundaries curves (hkl).

Effects of soap-water wash on human epidermal penetration.

Science.gov (United States)

Zhu, Hanjiang; Jung, Eui-Chang; Phuong, Christina; Hui, Xiaoying; Maibach, Howard

2016-08-01

Skin decontamination is a primary interventional method used to decrease dermal absorption of hazardous contaminants, including chemical warfare agents, pesticides and industrial pollutants. Soap and water wash, the most common and readily available decontamination system, may enhance percutaneous absorption through the "wash-in effect." To understand better the effect of soap-water wash on percutaneous penetration, and provide insight to improving skin decontamination methods, in vitro human epidermal penetration rates of four C(14) -labeled model chemicals (hydroquinone, clonidine, benzoic acid and paraoxon) were assayed using flow-through diffusion cells. Stratum corneum (SC) absorption rates of these chemicals at various hydration levels (0-295% of the dry SC weights) were determined and compared with the results of the epidermal penetration study to clarify the effect of SC hydration on skin permeability. Results showed accelerated penetration curves of benzoic acid and paraoxon after surface wash at 30 min postdosing. Thirty minutes after washing (60 min postdosing), penetration rates of hydroquinone and benzoic acid decreased due to reduced amounts of chemical on the skin surface and in the SC. At the end of the experiment (90 min postdosing), a soap-water wash resulted in lower hydroquinone penetration, greater paraoxon penetration and similar levels of benzoic acid and clonidine penetration compared to penetration levels in the non-wash groups. The observed wash-in effect agrees with the enhancement effect of SC hydration on the SC chemical absorption rate. These results suggest SC hydration derived from surface wash to be one cause of the wash-in effect. Further, the occurrence of a wash-in effect is dependent on chemical identity and elapsed time between exposure and onset of decontamination. By reducing chemical residue quantity on skin surface and in the SC reservoir, the soap-water wash may decrease the total quantity of chemical absorbed in the

'If an Eye Is Washed Properly, It Means It Would See Clearly': A Mixed Methods Study of Face Washing Knowledge, Attitudes, and Behaviors in Rural Ethiopia.

Directory of Open Access Journals (Sweden)

Kristen Aiemjoy

2016-10-01

Full Text Available Face cleanliness is a core component of the SAFE (Surgery, Antibiotics, Facial cleanliness, and Environmental improvements strategy for trachoma control. Understanding knowledge, attitudes, and behaviors related to face washing may be helpful for designing effective interventions for improving facial cleanliness.In April 2014, a mixed methods study including focus groups and a quantitative cross-sectional study was conducted in the East Gojjam zone of the Amhara region of Ethiopia. Participants were asked about face washing practices, motivations for face washing, use of soap (which may reduce bacterial load, and fly control strategies.Overall, both knowledge and reported practice of face washing was high. Participants reported they knew that washing their own face and their children's faces daily was important for hygiene and infection control. Although participants reported high knowledge of the importance of soap for face washing, quantitative data revealed strong variations by community in the use of soap for face washing, ranging from 4.4% to 82.2% of households reporting using soap for face washing. Cost and forgetfulness were cited as barriers to the use of soap for face washing. Keeping flies from landing on children was a commonly cited motivator for regular face washing, as was trachoma prevention.Interventions aiming to improve facial cleanliness for trachoma prevention should focus on habit formation (to address forgetfulness and address barriers to the use of soap, such as reducing cost. Interventions that focus solely on improving knowledge may not be effective for changing face-washing behaviors.

Nasal Wash Treatment

Science.gov (United States)

... Medications Alternative Therapies Nasal Wash Treatment Nasal Wash Treatment Make an Appointment Ask a Question Refer Patient The Centers for Disease Control (CDC) guidelines for preparing water used in a nasal wash are listed below. Many ...

Evaluation of microplastic release caused by textile washing processes of synthetic fabrics.

Science.gov (United States)

De Falco, Francesca; Gullo, Maria Pia; Gentile, Gennaro; Di Pace, Emilia; Cocca, Mariacristina; Gelabert, Laura; Brouta-Agnésa, Marolda; Rovira, Angels; Escudero, Rosa; Villalba, Raquel; Mossotti, Raffaella; Montarsolo, Alessio; Gavignano, Sara; Tonin, Claudio; Avella, Maurizio

2018-05-01

A new and more alarming source of marine contamination has been recently identified in micro and nanosized plastic fragments. Microplastics are difficult to see with the naked eye and to biodegrade in marine environment, representing a problem since they can be ingested by plankton or other marine organisms, potentially entering the food web. An important source of microplastics appears to be through sewage contaminated by synthetic fibres from washing clothes. Since this phenomenon still lacks of a comprehensive analysis, the objective of this contribution was to investigate the role of washing processes of synthetic textiles on microplastic release. In particular, an analytical protocol was set up, based on the filtration of the washing water of synthetic fabrics and on the analysis of the filters by scanning electron microscopy. The quantification of the microfibre shedding from three different synthetic fabric types, woven polyester, knitted polyester, and woven polypropylene, during washing trials simulating domestic conditions, was achieved and statistically analysed. The highest release of microplastics was recorded for the wash of woven polyester and this phenomenon was correlated to the fabric characteristics. Moreover, the extent of microfibre release from woven polyester fabrics due to different detergents, washing parameters and industrial washes was evaluated. The number of microfibres released from a typical 5 kg wash load of polyester fabrics was estimated to be over 6,000,000 depending on the type of detergent used. The usage of a softener during washes reduces the number of microfibres released of more than 35%. The amount and size of the released microfibres confirm that they could not be totally retained by wastewater treatments plants, and potentially affect the aquatic environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Oak Ridge National Laboratory Melton Valley Storage Tanks Waste filtration process evaluation

International Nuclear Information System (INIS)

Walker, B.W.; McCabe, D.J.

1997-01-01

The purpose of this filter study was to evaluate cross-flow filtration as effective solid-liquid separation technology for treating Oak Ridge National Laboratory wastes, outline operating conditions for equipment, examine the expected filter flow rates, and determine proper cleaning.The Gunite Tanks at the Oak Ridge National Laboratory contain heels which are a mixture of sludge, wash water, and bentonite clay. The tanks are to be cleaned out with a variety of flushing techniques and the dilute mixture transferred to another storage tank. One proposal is to transfer this mixture into existing Melton Valley Storage Tanks (MVST), which already contain a large amount of sludge and supernate. The mixed aqueous phase will then be transferred to new MVST, which are prohibited from containing insoluble solids. To separate the solid from the liquid and thereby prevent solids transfer into the new MVST, a technique is needed that can cleanly separate the sludge and bentonite clay from the supernate. One proposed method for solid liquid separation is cross-flow filtration. Cross-flow filtration has been used at the Savannah River and West Valley sites for treatment of tank waste, and is being tested for applicability at other sites. The performance of cross-flow filters with sludge has been tested, but the impact of sludge combined with bentonite clay has not. The objective of this test was to evaluate the feasibility of using cross-flow filters to perform the solid liquid separation required for the mixture of Gunite and MVST tank wastes

Using one filter stage of unsaturated/saturated vertical flow filters for nitrogen removal and footprint reduction of constructed wetlands.

Science.gov (United States)

Morvannou, Ania; Troesch, Stéphane; Esser, Dirk; Forquet, Nicolas; Petitjean, Alain; Molle, Pascal

2017-07-01

French vertical flow constructed wetlands (VFCW) treating raw wastewater have been developed successfully over the last 30 years. Nevertheless, the two-stage VFCWs require a total filtration area of 2-2.5 m 2 /P.E. Therefore, implementing a one-stage system in which treatment performances reach standard requirements is of interest. Biho-Filter ® is one of the solutions developed in France by Epur Nature. Biho-Filter ® is a vertical flow system with an unsaturated layer at the top and a saturated layer at the bottom. The aim of this study was to assess this new configuration and to optimize its design and operating conditions. The hydraulic functioning and pollutant removal efficiency of three different Biho-Filter ® plants commissioned between 2011 and 2012 were studied. Outlet concentrations of the most efficient Biho-Filter ® configuration are 70 mg/L, 15 mg/L, 15 mg/L and 25 mg/L for chemical oxygen demand (COD), 5-day biological oxygen demand (BOD 5 ), total suspended solids (TSS) and total Kjeldahl nitrogen (TKN), respectively. Up to 60% of total nitrogen is removed. Nitrification efficiency is mainly influenced by the height of the unsaturated zone and the recirculation rate. The optimum recirculation rate was found to be 100%. Denitrification in the saturated zone works at best with an influent COD/NO 3 -N ratio at the inflet of this zone larger than 2 and a hydraulic retention time longer than 0.75 days.

Cross-flow analysis of injection wells in a multilayered reservoir

Directory of Open Access Journals (Sweden)

Mohammadreza Jalali

2016-09-01

Natural and forced cross-flow is modeled for some injection wells in an oil reservoir located at North Sea. The solution uses a transient implicit finite difference approach for multiple sand layers with different permeabilities separated by impermeable shale layers. Natural and forced cross-flow rates for each reservoir layer during shut-in are calculated and compared with different production logging tool (PLT measurements. It appears that forced cross-flow is usually more prolonged and subject to a higher flow rate when compared with natural cross-flow, and is thus worthy of more detailed analysis.

Mean streamline analysis for performance prediction of cross-flow fans

International Nuclear Information System (INIS)

Kim, Jae Won; Oh, Hyoung Woo

2004-01-01

This paper presents the mean streamline analysis using the empirical loss correlations for performance prediction of cross-flow fans. Comparison of overall performance predictions with test data of a cross-flow fan system with a simplified vortex wall scroll casing and with the published experimental characteristics for a cross-flow fan has been carried out to demonstrate the accuracy of the proposed method. Predicted performance curves by the present mean streamline analysis agree well with experimental data for two different cross-flow fans over the normal operating conditions. The prediction method presented herein can be used efficiently as a tool for the preliminary design and performance analysis of general-purpose cross-flow fans

Soft sensing for two-phase flow using an ensemble Kalman filter

NARCIS (Netherlands)

Gryzlov, A.; Leskens, M.; Mudde, R.F.

2009-01-01

A new approach for real-time monitoring of horizontal wells, which is based on data assimilation concepts, is presented. Such methodology can be used when the direct measurement of multiphase flow rates is unfeasible or even unavailable. The real-time estimator proposed is an ensemble Kalman filter

Performance and internal flow characteristics of a cross-flow turbine by guide vane angle

International Nuclear Information System (INIS)

Chen, Z M; Choi, Y D

2013-01-01

This study attempts to investigate the performance and internal flow characteristics of a cross-flow turbine by guide vane angle. In order to improve the performance of a cross flow turbine, the paper presents a numerical investigation of the turbine with air supply and discusses the influence of variable guide vane angle on the internal flow. A newly developed air supply from air suction Hole is adopted. To investigate the performance and internal flow of the cross-flow turbine, the CFD software based on the two-phase flow model is utilized. The numerical grids are made in two-dimensional geometry in order to shorten the time of two-phase calculations. Then a series of CFD analysis has been conducted in the range of different guide vane angle. Moreover, local output power is divided at different stages and the effect of air layer in each stage is examined

Separating particles from a liquid

International Nuclear Information System (INIS)

Leslie, C.M.; Watson, J.H.P.; Williams, J.A.

1980-01-01

An apparatus for separating particles suspended in a liquid from the liquid, is described, in which a flow of the liquid is passed through a filter bed of ferromagnetic bodies which acts as a coarse filter to trap the larger particles in the flow. The filter bed is arranged within a truncated core between the poles of an electromagnet. To cleanse the bed and flush out the trapped particles a wash liquid is passed through the bed and the electromagnet is energised to levitate the bed to allow the wash liquid to remove the particles. The liquid flow from the coarse filter can be passed to a high gradient magnetic separator at which remaining small particles in the flow are filtered magnetically. (U.K.)

Winter Maintenance Wash-Water Heavy Metal Removal Pilot Scale Evaluation

Directory of Open Access Journals (Sweden)

Christopher M. Miller

2016-01-01

Full Text Available To encourage sustainable engineering practices, departments of transportation are interested in reusing winter maintenance truck wash water as part of their brine production and future road application. Traffic-related metals in the wash water, however, could limit this option. The objective of this work was to conduct a pilot scale evaluation of heavy metal (copper, zinc, iron, and lead removal in a filtration unit (maximum flow rate of 45 L/minute containing proprietary (MAR Systems Sorbster® media. Three different trials were conducted and approximately 10,000 L of wash water collected from a winter maintenance facility in Ohio was treated with the pilot unit. Lab studies were also performed on six wash-water samples from multiple facilities to assess particle size removal and estimate settling time as a potential removal mechanism during wash-water storage. Pilot unit total metal removal efficiencies were 79%, 77%, 63%, and 94% for copper, zinc, iron, and lead, respectively. Particle settling calculation estimates for copper and zinc show that 10 hours in storage can also effectively reduce heavy metal concentrations in winter maintenance wash water in excess of 70%. These pilot scale results show promise for reducing heavy metal concentrations to an acceptable level for reuse.

TESTING OF THE SECOND GENERATION SPINTEK ROTARY FILTER -11357

Energy Technology Data Exchange (ETDEWEB)

Herman, D.; Poirier, M.; Fowley, M.; Keefer, M.; Huff, T.

2011-02-02

The SpinTek rotary microfilter has been developed under the Department of Energy (DOE) Office of Environmental Management (EM) for the purpose of deployment in radioactive service in the DOE complex. The unit that was fabricated and tested is the second generation of the filter that incorporates recommended improvements from previous testing. The completion of this test satisfied a key milestone for the EM technology development program and technology readiness for deployment by Savannah River Remediation in the Small Column Ion Exchange and Sludge Washing processes at the Savannah River Site (SRS). The Savannah River National Laboratory (SRNL) contracted SpinTek Filtration to fabricate a full scale 25 disk rotary filter and perform a 1000 hour endurance test with a simulated SRS sludge. Over 1500 hours of operation have been completed with the filter. SpinTek Filtration fabricated a prototypic 25 disk rotary filter including updates to manufacturing tolerances, an updated design to the rotary joint, improved cooling to the bottom journal, decreases in disk and filter shaft hydraulic resistances. The filter disks were fabricated with 0.5 {micro} pore size, sintered-metal filter media manufactured by Pall Corporation (M050). After fabrication was complete, the filter passed acceptance tests demonstrating rejection of solids and clean water flux with a 50% improvement over the previous filters. Once the acceptance test was complete, a 1000 hour endurance test was initiated simulating a sludge washing process. The test used a simulated SRS Sludge Batch 6 recipe. The insoluble solids started at 5 wt% and were raised to 10 and 15 wt% insoluble solids to simulate the concentration of a large volume tank. The filter system was automated and set up for 24 hour unattended operation. To facilitate this, process control logic was written to operate the filter. During the development it was demonstrated that the method of starting and stopping the filter can affect the build

Effect of induced cross flow on flow pattern and performance of proton exchange membrane fuel cell

International Nuclear Information System (INIS)

Jiao, Kui; Bachman, John; Zhou, Yibo; Park, Jae Wan

2014-01-01

Highlights: • 3D numerical works to study the effect of cross flow on the PEMFC performance. • The cross flow ensure more evenly distributed water and oxygen in the CL. • The optimal net power output can be identified by controlling the back pressure. • Results confirm that present design is effective in improving performance. - Abstract: The cross flow in proton exchange membrane fuel cells (PEMFCs) plays an important role in changing the transport pattern and performance. In this study, three-dimensional numerical simulations are carried out to investigate the effect of induced cross flow on the flow pattern and performance of a PEMFC with a previously proposed and experimentally studied novel parallel flow channel design. The numerical results indicate that the liquid water and oxygen become more evenly distributed in the catalyst layer (CL) as the pressure difference between the low-pressure and high-pressure flow channels increases. It has been found that, in the low-pressure channels, the cross flow drives a convective flow from the CL to the flow channel resulting in improved liquid water removal. The optimal net power output can be identified by controlling the back pressure on the high-pressure flow channels. The numerical results confirm that this novel parallel flow channel design is effective in improving PEMFC performance

Water flow experiments and analyses on the cross-flow type mercury target model with the flow guide plates

CERN Document Server

Haga, K; Kaminaga, M; Hino, R

2001-01-01

A mercury target is used in the spallation neutron source driven by a high-intensity proton accelerator. In this study, the effectiveness of the cross-flow type mercury target structure was evaluated experimentally and analytically. Prior to the experiment, the mercury flow field and the temperature distribution in the target container were analyzed assuming a proton beam energy and power of 1.5 GeV and 5 MW, respectively, and the feasibility of the cross-flow type target was evaluated. Then the average water flow velocity field in the target mock-up model, which was fabricated from Plexiglass for a water experiment, was measured at room temperature using the PIV technique. Water flow analyses were conducted and the analytical results were compared with the experimental results. The experimental results showed that the cross-flow could be realized in most of the proton beam path area and the analytical result of the water flow velocity field showed good correspondence to the experimental results in the case w...

The flows structure in unsteady gas flow in pipes with different cross-sections

Science.gov (United States)

Plotnikov, Leonid; Nevolin, Alexandr; Nikolaev, Dmitrij

2017-10-01

The results of numerical simulation and experimental study of the structure of unsteady flows in pipes with different cross sections are presented in the article. It is shown that the unsteady gas flow in a circular pipe is axisymmetric without secondary currents. Steady vortex structures (secondary flows) are observed in pipes with cross sections in the form of a square and an equilateral triangle. It was found that these secondary flows have a significant impact on gas flows in pipes of complex configuration. On the basis of experimental researches it is established that the strong oscillatory phenomena exist in the inlet pipe of the piston engine arising after the closing of the intake valve. The placement of the profiled plots (with a cross section of a square or an equilateral triangle) in the intake pipe leads to the damping of the oscillatory phenomena and a more rapid stabilization of pulsating flow. This is due to the stabilizing effect of the vortex structures formed in the corners of this configuration.

The flows structure in unsteady gas flow in pipes with different cross-sections

Directory of Open Access Journals (Sweden)

Plotnikov Leonid

2017-01-01

Full Text Available The results of numerical simulation and experimental study of the structure of unsteady flows in pipes with different cross sections are presented in the article. It is shown that the unsteady gas flow in a circular pipe is axisymmetric without secondary currents. Steady vortex structures (secondary flows are observed in pipes with cross sections in the form of a square and an equilateral triangle. It was found that these secondary flows have a significant impact on gas flows in pipes of complex configuration. On the basis of experimental researches it is established that the strong oscillatory phenomena exist in the inlet pipe of the piston engine arising after the closing of the intake valve. The placement of the profiled plots (with a cross section of a square or an equilateral triangle in the intake pipe leads to the damping of the oscillatory phenomena and a more rapid stabilization of pulsating flow. This is due to the stabilizing effect of the vortex structures formed in the corners of this configuration.

Oxygen profile and clogging in vertical flow sand filters for on-site wastewater treatment.

Science.gov (United States)

Petitjean, A; Forquet, N; Boutin, C

2016-04-01

13 million people (about 20% of the population) use on-site wastewater treatment in France. Buried vertical sand filters are often built, especially when the soil permeability is not sufficient for septic tank effluent infiltration in undisturbed soil. Clogging is one of the main problems deteriorating the operation of vertical flow filters for wastewater treatment. The extent of clogging is not easily assessed, especially in buried vertical flow sand filters. We suggest examining two possible ways of detecting early clogging: (1) NH4-N/NO3-N outlet concentration ratio, and (2) oxygen measurement within the porous media. Two pilot-scale filters were equipped with probes for oxygen concentration measurements and samples were taken at different depths for pollutant characterization. Influent and effluent grab-samples were taken three times a week. The systems were operated using batch-feeding of septic tank effluent. Qualitative description of oxygen transfer processes under unclogged and clogged conditions is presented. NH4-N outlet concentration appears to be useless for early clogging detection. However, NO3-N outlet concentration and oxygen content allows us to diagnose the early clogging of the system. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of closed immersion filtered water flow velocity on the ablation threshold of bisphenol A polycarbonate during excimer laser machining

International Nuclear Information System (INIS)

Dowding, Colin; Lawrence, Jonathan

2010-01-01

A closed flowing thick film filtered water immersion technique ensures a controlled geometry for both the optical interfaces of the flowing liquid film and allows repeatable control of flow-rate during machining. This has the action of preventing splashing, ensures repeatable machining conditions and allows control of liquid flow velocity. To investigate the impact of this technique on ablation threshold, bisphenol A polycarbonate samples have been machined using KrF excimer laser radiation passing through a medium of filtered water flowing at a number of flow velocities, that are controllable by modifying the liquid flow-rates. An average decrease in ablation threshold of 7.5% when using turbulent flow velocity regime closed thick film filtered water immersed ablation, compared to ablation using a similar beam in ambient air; however, the use of laminar flow velocities resulted in negligible differences between closed flowing thick film filtered water immersion and ambient air. Plotting the recorded threshold fluence achieved with varying flow velocity showed that an optimum flow velocity of 3.00 m/s existed which yielded a minimum ablation threshold of 112 mJ/cm 2 . This is attributed to the distortion of the ablation plume effected by the flowing immersion fluid changing the ablation mechanism: at laminar flow velocities Bremsstrahlung attenuation decreases etch rate, at excessive flow velocities the plume is completely destroyed, removing the effect of plume etching. Laminar flow velocity regime ablation is limited by slow removal of debris causing a non-linear etch rate over 'n' pulses which is a result of debris produced by one pulse remaining suspended over the feature for the next pulse. The impact of closed thick film filtered water immersed ablation is dependant upon beam fluence: high fluence beams achieved greater etch efficiency at high flow velocities as the effect of Bremsstrahlung attenuation is removed by the action of the fluid on the plume; low

Respirator Filter Efficiency Testing Against Particulate and Biological Aerosols Under Moderate to High Flow Rates

Science.gov (United States)

2006-08-01

flow rate through the test filter. The flow rate was measured using a mass flow meter (Series 4000, TSI, Shoreview, MN). Several modifications were made...operating conditions. This included assessing the effect of non- isokinetic sampling, flow calibrations, and characterization of the challenge...sampling bias on the measured penetrations due to the non- isokinetic sampling downstream. 3.3.2.2 System Characterization. Shakedown tests were

Thermal performance modeling of cross-flow heat exchangers

CERN Document Server

Cabezas-Gómez, Luben; Saíz-Jabardo, José Maria

2014-01-01

This monograph introduces a numerical computational methodology for thermal performance modeling of cross-flow heat exchangers, with applications in chemical, refrigeration and automobile industries. This methodology allows obtaining effectiveness-number of transfer units (e-NTU) data and has been used for simulating several standard and complex flow arrangements configurations of cross-flow heat exchangers. Simulated results have been validated through comparisons with results from available exact and approximate analytical solutions. Very accurate results have been obtained over wide ranges

Can a numerically stable subgrid-scale model for turbulent flow computation be ideally accurate?: a preliminary theoretical study for the Gaussian filtered Navier-Stokes equations.

Science.gov (United States)

Ida, Masato; Taniguchi, Nobuyuki

2003-09-01

This paper introduces a candidate for the origin of the numerical instabilities in large eddy simulation repeatedly observed in academic and practical industrial flow computations. Without resorting to any subgrid-scale modeling, but based on a simple assumption regarding the streamwise component of flow velocity, it is shown theoretically that in a channel-flow computation, the application of the Gaussian filtering to the incompressible Navier-Stokes equations yields a numerically unstable term, a cross-derivative term, which is similar to one appearing in the Gaussian filtered Vlasov equation derived by Klimas [J. Comput. Phys. 68, 202 (1987)] and also to one derived recently by Kobayashi and Shimomura [Phys. Fluids 15, L29 (2003)] from the tensor-diffusivity subgrid-scale term in a dynamic mixed model. The present result predicts that not only the numerical methods and the subgrid-scale models employed but also only the applied filtering process can be a seed of this numerical instability. An investigation concerning the relationship between the turbulent energy scattering and the unstable term shows that the instability of the term does not necessarily represent the backscatter of kinetic energy which has been considered a possible origin of numerical instabilities in large eddy simulation. The present findings raise the question whether a numerically stable subgrid-scale model can be ideally accurate.

Hand washing practices amongst medical students in Port Harcourt ...

African Journals Online (AJOL)

Alasia Datonye

Background: Hand washing with soap and water is one of ... Method: This was a descriptive cross sectional survey ... simple questionnaire exploring perceptions, attitudes and ... Many studies have shown that doctors decontaminating their hands between seeing patients ..... countries: a systematic review and meta analysis.

Soil washing and post-wash biological treatment of petroleum hydrocarbon contaminated soils

OpenAIRE

Bhandari, Alok

1992-01-01

A laboratory scale study was conducted to investigate the treatability of petroleum contaminated soils by soil washing and subsequent biological treatment of the different soil fractions. In addition to soils obtained from contaminated sites, studies were also performed on soils contaminated in the laboratory. Soil washing was performed using a bench-scale soil washing system. Washing was carried out with simultaneous fractionation of the bulk soil into sand, silt and clay fractions. Cl...

Recleaning of HEPA filters by reverse flow - evaluation of the underlying processes and the cleaning technique

International Nuclear Information System (INIS)

Leibold, H.; Leiber, T.; Doeffert, I.; Wilhelm, J.G.

1993-08-01

HEPA filter operation at high concentrations of fine dusts requires the periodic recleaning of the filter units in their service locations. Due to the low mechanical stress induced during the recleaning process the regenration via low pressure reverse flow is a very suitable technique. Recleanability of HEPA filter had been attained for particle diameter >0,4 μm at air velocities up to 1 m/s, but filter clogging occurred in case of smaller particles. The recleaning forces are too weak for particles [de

Cascade ultrafiltering of 210Pb and 210Po in freshwater using a tangential flow filtering system

International Nuclear Information System (INIS)

Ohtsuka, Y.; Takaku, Y.; Hisamatsu, S.; Inaba, J.; Yamamoto, M.

2006-01-01

A rapid method was developed using ultrafilters with a tangential flow filtering system for molecular size separation of naturally occurring 210 Pb and 210 Po in a freshwater sample. Generally, ultrafiltering of a large volume water sample for measuring the nuclides was too time consuming and not practical. The tangential flow filtering system made the filtering time short enough to adapt for in-situ ultrafiltering the large volume sample. In this method, a 20 liter water sample was at first passed through the 0.45 μm pore size membrane filter immediately after sample collection to obtain suspended particle matter [>0.45 μm particulate fraction (PRT)]. Two ultrafilters (Millipore Pellicon 2 R ) were used sequentially. The nuclides in the filtrate were separated into three fractions: high molecular mass (100 kDa-0.45μm; HMM), low molecular mass (10 k-100 kDa; LMM) and ionic ( 210 Pb and 210 Po in an oligotrophic lake, Lake Towada located in the northern area of Japan. (author)

Device for automatic filter changing. Einrichtung zum selbsttaetigen Wechseln eines Filters

Energy Technology Data Exchange (ETDEWEB)

Matschoss, V; Naschwitz, A; Wild, H

1984-01-05

A filter is moved from a store to an aerosol pipe by a lifting device and is clamped there. At the end of the operating period, the lifting device moves a new filter to a parking place. Control is from limit switches of the lifting, clamping and thrust devices and the position control of the store is by the limit switches. The filter changing device is enclosed in a gastight case, prevents blockage of a filter and makes it possible to set a certain operating period, to change the filter without interrupting the aerosol flow and to measure each filter in the sequence of operation outside the aerosol flow.

Flow of Hydrolysed Polyacrylamide Mother Liquor through Filter Bag: Detecting the Effects of Formulation and Process Properties on Pressure Drop

Directory of Open Access Journals (Sweden)

Zi-Ming Feng

2016-01-01

Full Text Available Hydrolysed polyacrylamide (HPAM mother liquor is mainly used to extract oil. The HPAM solution is needed to filter the impurity using a bag filter before it is injected into the oil well. Therefore, the pressure drop of HPAM mother liquor must be less than 0.02 MPa in the processing of impurity filtration. The influence factors on pressure drop need to be researched. In this work, the computational fluid dynamics program (CFD was used to research some key influence factors on pressure drop, such as porosity, outlet pressure of filter, inlet flow rate and viscosity of mother liquor. The simulation results indicated that with increasing porosity, outlet pressure, inlet flow rate and mother liquor viscosity, the pressure drop had increased after flowing through the filter bag.

Visualization of Two Phase Flow in a Horizontal Flow with Electrical Resistance Tomography based on Extended Kalman Filter

International Nuclear Information System (INIS)

Lee, Jeong Seong; Malik, Nauman Muhammad; Khambampati, Anil Kumar; Rashid, Ahmar; Kim, Sin; Kim, Kyung Youn

2008-01-01

For the visualization of the phase distribution in two phase flows, the electrical resistance tomography (ERT) technique is introduced. In ERT, the internal resistivity distribution is reconstructed based on the known sets of the injected currents and measured voltages on the surface of the object. The physical relationship between the internal resistivity and the surface voltages is governed by a partial differential equation with appropriate boundary conditions. This paper considers the estimation of the phase distribution with ERT in two phase flow in a horizontal flow using extended Kalman filter. To evaluate the reconstruction performance of the proposed algorithm, the experiments simulated two phase flows in a horizontal flow were carried out. The experiments with two phase flow phantom were done to suggest a practical implication of this research in detecting gas bubble in a feed water pipe of heat transfer systems

Illustration of cross flow of polystyrene melts through a coathanger die

Science.gov (United States)

Schöppner, V.; Henke, B.

2015-05-01

To design an optimal coathanger die with a uniform flow rate distribution and low pressure drop, it is essential to understand the flow conditions in the die. This is important because the quality of the product is influenced by the flow velocity and the flow rate distribution. In extrusion dies, cross flows also occur in addition to the main flow, which flow perpendicular to the main flow. This results in pressure gradients in the extrusion direction, which have an influence on flow distribution and pressure drop in the die. In recent decades, quantitative representation and analysis of physical flow processes have made considerable progress in predicting the weather, developing drive technologies and designing aircraft using simulation methods and lab trials. Using the flow-line method, the flow is analyzed in flat film extrusion dies with a rectangular cross-section, in particular cross flows. The simplest method to visualize the flow is based on the measurement of obstacle orientation in the flow field by adding individual particles. A near-surface flow field can be visualized by using wool or textile yarns. By sticking thin, frayed at the ends of strands of wool surface that is to be examined cross flows, near-wall profiles of the flow and vortex and separation regions can be visualized. A further possibility is to add glass fibers and analyze the fiber orientation by microscopy and x-ray analysis. In this paper the influence of process parameters (e.g. melt temperatures and throughput) on cross flow and fiber orientation is described.

Palladium-Catalyzed Suzuki–Miyaura Cross-Coupling in Continuous Flow

Directory of Open Access Journals (Sweden)

Christophe Len

2017-05-01

Full Text Available Carbon–carbon cross-coupling reactions are among the most important processes in organic chemistry and Suzuki–Miyaura reactions are the most widely used protocols. For a decade, green chemistry and particularly catalysis and continuous flow, have shown immense potential in achieving the goals of “greener synthesis”. To date, it seems difficult to conceive the chemistry of the 21st century without the industrialization of continuous flow process in the area of pharmaceuticals, drugs, agrochemicals, polymers, etc. A large variety of palladium Suzuki–Miyaura cross-coupling reactions have been developed using a continuous flow sequence for preparing the desired biaryl derivatives. Our objective is to focus this review on the continuous flow Suzuki–Miyaura cross-coupling using homogeneous and heterogeneous catalysts.

Numerical simulation of flow characteristics of lean jet to cross-flow in safety injection of reactor cooling system

International Nuclear Information System (INIS)

Wang Haijun; He Huining; Luo Yushan; Wang Weishu

2011-01-01

In the present work, a numerical simulation was performed to study the flow characteristics of lean jet to cross flow in a main tube in the safety injection of reactor cooling system. The influence scope and mixing characteristics of the confined lean jet in cross-flow were studied. It can be concluded that three basic flow regimes are marked, namely the attached lean jet, lift-off lean jet and impinging lean jet. The velocity ratio V R is the key factor in the flow state. The depth and region of jet to main flow are enhanced with the increase of the velocity ratio. The jet flow penetrates through the main flow with the increase of the velocity ratio. At higher velocity ratio, the jet flow strikes the main flow bottom and circumfluence happens in upriver of main flow. The vortex flow characteristics dominate the flow near region of jet to cross-flow and the mixture of jet to cross-flow. At different velocity ratio V R , the vortex grows from the same displacement, but the vortex type and the vortex is different. At higher velocity ratio, the vortex develops fleetly, wears off sharp and dies out sharp. The study is very important to the heat transfer experiments of cross-flow jet and thermal stress analysis in the designs of nuclear engineering. (authors)

Transport reduction via shear flow modification of the cross phase

International Nuclear Information System (INIS)

Ware, A.S.; Terry, P.W.; Diamond, P.H.; Carreras, B.A.

1996-01-01

As a model example of the effect of E x B shear flow on the cross phase between electrostatic potential and pressure fluctuations, a nonlinear theory of resistive pressure gradient driven turbulence (RPGDT) in a shear flow is presented. This work builds on numerical studies of RPGDT, which have shown that both flow shear and curvature can affect the cross phase as well as the fluctuation levels. In this work, we show that the effect of shear flow on transport can be expressed through the temporal response of pressure to potential. It is shown heuristically that even in the case where the fluctuation levels are not modified, the flow shear still acts to reduce the phase angle between potential and pressure fluctuations, thereby suppressing transport. The scaling of the cross phase with flow shear and flow curvature is presented. (author)

Sandstone-body and shale-body dimensions in a braided fluvial system: Salt wash sandstone member (Morrison formation), Garfield County, Utah

Science.gov (United States)

Robinson, J.W.; McCabea, P.J.

1997-01-01

Excellent three-dimensional exposures of the Upper Jurassic Salt Wash Sandstone Member of the Morrison Formation in the Henry Mountains area of southern Utah allow measurement of the thickness and width of fluvial sandstone and shale bodies from extensive photomosaics. The Salt Wash Sandstone Member is composed of fluvial channel fill, abandoned channel fill, and overbank/flood-plain strata that were deposited on a broad alluvial plain of low-sinuosity, sandy, braided streams flowing northeast. A hierarchy of sandstone and shale bodies in the Salt Wash Sandstone Member includes, in ascending order, trough cross-bedding, fining-upward units/mudstone intraclast conglomerates, singlestory sandstone bodies/basal conglomerate, abandoned channel fill, multistory sandstone bodies, and overbank/flood-plain heterolithic strata. Trough cross-beds have an average width:thickness ratio (W:T) of 8.5:1 in the lower interval of the Salt Wash Sandstone Member and 10.4:1 in the upper interval. Fining-upward units are 0.5-3.0 m thick and 3-11 m wide. Single-story sandstone bodies in the upper interval are wider and thicker than their counterparts in the lower interval, based on average W:T, linear regression analysis, and cumulative relative frequency graphs. Multistory sandstone bodies are composed of two to eight stories, range up to 30 m thick and over 1500 m wide (W:T > 50:1), and are also larger in the upper interval. Heterolithic units between sandstone bodies include abandoned channel fill (W:T = 33:1) and overbank/flood-plain deposits (W:T = 70:1). Understanding W:T ratios from the component parts of an ancient, sandy, braided stream deposit can be applied in several ways to similar strata in other basins; for example, to (1) determine the width of a unit when only the thickness is known, (2) create correlation guidelines and maximum correlation lengths, (3) aid in interpreting the controls on fluvial architecture, and (4) place additional constraints on input variables to

Comparison of the laboratory standard washing using CIPAC washing agent and the domestic washing on three recommended types of long-lasting insecticidal mosquito nets.

Science.gov (United States)

Ouattara, Jean Pierre Nabléni; Louwagie, Johanna; Pigeon, Olivier; Spanoghe, Pieter

2013-01-01

One of the best ways to prevent malaria is the use of insecticide-treated bed nets. Manufacturers pursue easier, safer and more efficient nets. Hence, many studies on the efficacy and wash resistance using World Health Organization standards have been reported. The commonly used detergent is "Savon de Marseille", because it closely resembles actually used soaps. At the 54(th) Collaborative International Pesticides Analytical Council (CIPAC) Technical Meeting in 2010, it was suggested to replace it by a standardized "CIPAC washing agent". The aim of this study was to investigate the difference between a laboratory hand washing simulation using the CIPAC washing agent (method-1) and a domestic washing (method-2) on different bed nets, as well as the effect of the drying process on the release of active ingredient. Interceptor®, Permanet®2.0 and Netprotect® nets were used in three treatments, each repeated 20 times. The first treatment included method-1 washing and indoor drying. The second treatment included method-2 washing and indoor drying. The third treatment used method-2 washing and UV-drying. The residual insecticide contents were determined using gas chromatography. The washing procedure and the number of washes have a significant effect on the release of active ingredient. Statistically, the two washing methods have the same effect on removing the active ingredient from the Interceptor® and Permanet®2.0 net, but a significantly different influence on the Netprotect® nets. The drying process has no significant effect on the insecticide. Both washing procedures affected the amount of insecticide remaining on nets independently of the impregnation technology. The active ingredient decreases with the number of washing cycles following an exponential or logarithmic model for coated nets. The laboratory hand washing simulation had more impact on the decrease of active ingredient content of the Netprotect® nets. All net types seemed to be effectively

Comparison of the laboratory standard washing using CIPAC washing agent and the domestic washing on three recommended types of long-lasting insecticidal mosquito nets.

Directory of Open Access Journals (Sweden)

Jean Pierre Nabléni Ouattara

Full Text Available One of the best ways to prevent malaria is the use of insecticide-treated bed nets. Manufacturers pursue easier, safer and more efficient nets. Hence, many studies on the efficacy and wash resistance using World Health Organization standards have been reported. The commonly used detergent is "Savon de Marseille", because it closely resembles actually used soaps. At the 54(th Collaborative International Pesticides Analytical Council (CIPAC Technical Meeting in 2010, it was suggested to replace it by a standardized "CIPAC washing agent". The aim of this study was to investigate the difference between a laboratory hand washing simulation using the CIPAC washing agent (method-1 and a domestic washing (method-2 on different bed nets, as well as the effect of the drying process on the release of active ingredient.Interceptor®, Permanet®2.0 and Netprotect® nets were used in three treatments, each repeated 20 times. The first treatment included method-1 washing and indoor drying. The second treatment included method-2 washing and indoor drying. The third treatment used method-2 washing and UV-drying. The residual insecticide contents were determined using gas chromatography.The washing procedure and the number of washes have a significant effect on the release of active ingredient. Statistically, the two washing methods have the same effect on removing the active ingredient from the Interceptor® and Permanet®2.0 net, but a significantly different influence on the Netprotect® nets. The drying process has no significant effect on the insecticide.Both washing procedures affected the amount of insecticide remaining on nets independently of the impregnation technology. The active ingredient decreases with the number of washing cycles following an exponential or logarithmic model for coated nets. The laboratory hand washing simulation had more impact on the decrease of active ingredient content of the Netprotect® nets. All net types seemed to be

Shell-crossing in quasi-one-dimensional flow

Science.gov (United States)

Rampf, Cornelius; Frisch, Uriel

2017-10-01

Blow-up of solutions for the cosmological fluid equations, often dubbed shell-crossing or orbit crossing, denotes the breakdown of the single-stream regime of the cold-dark-matter fluid. At this instant, the velocity becomes multi-valued and the density singular. Shell-crossing is well understood in one dimension (1D), but not in higher dimensions. This paper is about quasi-one-dimensional (Q1D) flow that depends on all three coordinates but differs only slightly from a strictly 1D flow, thereby allowing a perturbative treatment of shell-crossing using the Euler-Poisson equations written in Lagrangian coordinates. The signature of shell-crossing is then just the vanishing of the Jacobian of the Lagrangian map, a regular perturbation problem. In essence, the problem of the first shell-crossing, which is highly singular in Eulerian coordinates, has been desingularized by switching to Lagrangian coordinates, and can then be handled by perturbation theory. Here, all-order recursion relations are obtained for the time-Taylor coefficients of the displacement field, and it is shown that the Taylor series has an infinite radius of convergence. This allows the determination of the time and location of the first shell-crossing, which is generically shown to be taking place earlier than for the unperturbed 1D flow. The time variable used for these statements is not the cosmic time t but the linear growth time τ ˜ t2/3. For simplicity, calculations are restricted to an Einstein-de Sitter universe in the Newtonian approximation, and tailored initial data are used. However it is straightforward to relax these limitations, if needed.

Fluid-elastic vibration in two-phase cross flow

International Nuclear Information System (INIS)

Sasakawa, T.; Serizawa, A.; Kawara, Z.

2003-01-01

The present work aims at clarifying the mechanisms of fluid elastic vibration of tube bundles in two-phase cross flow. The experiment is conducted using air-water two-phase flow under atmospheric pressure. The test section is a 1.03m long transparent acrylic square duct with 128 x 128 mm 2 cross section, which consists of 3 rod-rows with 5 rods in each row. The rods are 125mm long aluminum rods with 22 mm in diameter (p/D=1.45). The natural frequency of rod vibration is about 30Hz. The result indicated a diversion of observed trend in vibration behavior depending on two-phase flow patterns either bubbly flow or churn flow. Specifically, in churn flow, the fluid elastic vibration has been observed to occur when the frequency in void fraction fluctuation approached to the natural frequency of the rods, but this was not the case in fluid elastic vibration in bubbly flow. This fact suggests the existence of mechanisms closely coupled with two-phase flow structures depending on the flow patterns, that is, static two-phase character-controlled mechanism in bubbly flow and dynamic character- controlled in churn flow

Flow velocity measurement by using zero-crossing polarity cross correlation method

International Nuclear Information System (INIS)

Xu Chengji; Lu Jinming; Xia Hong

1993-01-01

Using the designed correlation metering system and a high accurate hot-wire anemometer as a calibration device, the experimental study of correlation method in a tunnel was carried out. The velocity measurement of gas flow by using zero-crossing polarity cross correlation method was realized and the experimental results has been analysed

Dense Array Optimization of Cross-Flow Turbines

Science.gov (United States)

Scherl, Isabel; Strom, Benjamin; Brunton, Steven; Polagye, Brian

2017-11-01

Cross-flow turbines, where the axis of rotation is perpendicular to the freestream flow, can be used to convert the kinetic energy in wind or water currents to electrical power. By taking advantage of mean and time-resolved wake structures, the optimal density of an array of cross-flow turbines has the potential for higher power output per unit area of land or sea-floor than an equivalent array of axial-flow turbines. In addition, dense arrays in tidal or river channels may be able to further elevate efficiency by exploiting flow confinement and surface proximity. In this work, a two-turbine array is optimized experimentally in a recirculating water channel. The spacing between turbines, as well as individual and coordinated turbine control strategies are optimized. Array efficiency is found to exceed the maximum efficiency for a sparse array (i.e., no interaction between turbines) for stream-wise rotor spacing of less than two diameters. Results are discussed in the context of wake measurements made behind a single rotor.

Use of green washing fluids in a washing process for dioxin contaminated soils

Directory of Open Access Journals (Sweden)

Siwalee Yotapukdee

2017-09-01

Full Text Available High levels of dioxin contamination in soil have significant environmental challenges. Soil washing is a successful remediation process that is primarily used to treat coarse soils. Several literature studies have used various kinds of chemical washing liquids to remove dioxins from soils, though there are secondary environmental effects. This study intends to develop environmentally friendly soil washing methods that are effective in dioxin removal at an acceptable cost. Sugarcane wine, compost leachate, and ground fish broth were chosen as potential washing liquids. Each washing liquid was analyzed to determine its content of semivolatile organic compounds (SVOCs and volatile organic compounds (VOCs. These compounds are related to their bio-surfactant content. Several of the identified compounds had properties to help remove dioxins from contaminated soil. In the experiments, high removal efficiencies were observed, up to 70%~95% after five to six washes. Although effective removal was observed, a significant amount of wastewater was produced and the problems were not completely resolved. Thus, the optimal washing conditions are necessary to minimize the overall costs, while improving the process effectiveness. Moreover, an appropriate treatment method is required for wastewater containing dioxins.

The Cross-Flow Mixing Analysis of Quasi-Static Pebble Flow in Pebble Bed Reactor

International Nuclear Information System (INIS)

Fang Xiang; Liu Zhiyong; Sun Yanfei; Yang Xingtuan; Jiang Shengyao

2014-01-01

In the pebble bed reactor, large number of fuel pebbles’ movement law and moving state can affect the reactor’s design, operation and safety directly. Therefore the pebble flow, which is based on the theory of particle streaming, is one of the most important research subjects of the pebble bed reactor engineering. The in-core pebble flow is a very slow particle flow (or called quasi-static particle flow), which is very different from the usual particle motion. How to accurately describe the characteristics of in-core pebble flow is a central issue for this subject. Due to the presence of random flow, the cross-mixing phenomenon will occur inevitably. In the present paper, the mixing phenomenon of pebble flow is generalized on the basis of experiment results. The pebble flow cross-mixing probability serves as the parameter which describes both the regularity and the randomness of pebble flow. The results are provided in the form of diagrammatic presentation. (author)

Method and apparatus for a self-cleaning filter

Science.gov (United States)

Diebold, James P.; Lilley, Arthur; Browne, III, Kingsbury; Walt, Robb Ray; Duncan, Dustin; Walker, Michael; Steele, John; Fields, Michael

2010-11-16

A method and apparatus for removing fine particulate matter from a fluid stream without interrupting the overall process or flow. The flowing fluid inflates and expands the flexible filter, and particulate is deposited on the filter media while clean fluid is permitted to pass through the filter. This filter is cleaned when the fluid flow is stopped, the filter collapses, and a force is applied to distort the flexible filter media to dislodge the built-up filter cake. The dislodged filter cake falls to a location that allows undisrupted flow of the fluid after flow is restored. The shed particulate is removed to a bin for periodic collection. A plurality of filter cells can operate independently or in concert, in parallel, or in series to permit cleaning the filters without shutting off the overall fluid flow. The self-cleaning filter is low cost, has low power consumption, and exhibits low differential pressures.

Method and apparatus for a self-cleaning filter

Science.gov (United States)

Diebold, James P.; Lilley, Arthur; Browne, III, Kingsbury; Walt, Robb Ray; Duncan, Dustin; Walker, Michael; Steele, John; Fields, Michael

2013-09-10

A method and apparatus for removing fine particulate matter from a fluid stream without interrupting the overall process or flow. The flowing fluid inflates and expands the flexible filter, and particulate is deposited on the filter media while clean fluid is permitted to pass through the filter. This filter is cleaned when the fluid flow is stopped, the filter collapses, and a force is applied to distort the flexible filter media to dislodge the built-up filter cake. The dislodged filter cake falls to a location that allows undisrupted flow of the fluid after flow is restored. The shed particulate is removed to a bin for periodic collection. A plurality of filter cells can operate independently or in concert, in parallel, or in series to permit cleaning the filters without shutting off the overall fluid flow. The self-cleaning filter is low cost, has low power consumption, and exhibits low differential pressures.

Phase Resolved Angular Velocity Control of Cross Flow Turbines

Science.gov (United States)

Strom, Benjamin; Brunton, Steven; Polagye, Brian

2015-11-01

Cross flow turbines have a number of operational advantages for the conversion of kinetic energy in marine or fluvial currents, but they are often less efficient than axial flow devices. Here a control scheme is presented in which the angular velocity of a cross flow turbine with two straight blades is prescribed as a function of azimuthal blade position, altering the time-varying effective angle of attack. Flume experiments conducted with a scale model turbine show approximately an 80% increase in turbine efficiency versus optimal constant angular velocity and constant resistive torque control schemes. Torque, drag, and lateral forces on one- and two-bladed turbines are analyzed and interpreted with bubble flow visualization to develop a simple model that describes the hydrodynamics responsible for the observed increase in mean efficiency. Challenges associated with implementing this control scheme on commercial-scale devices are discussed. If solutions are found, the performance increase presented here may impact the future development of cross flow turbines.

Rating knowledge sharing in cross-domain collaborative filtering.

Science.gov (United States)

Li, Bin; Zhu, Xingquan; Li, Ruijiang; Zhang, Chengqi

2015-05-01

Cross-domain collaborative filtering (CF) aims to share common rating knowledge across multiple related CF domains to boost the CF performance. In this paper, we view CF domains as a 2-D site-time coordinate system, on which multiple related domains, such as similar recommender sites or successive time-slices, can share group-level rating patterns. We propose a unified framework for cross-domain CF over the site-time coordinate system by sharing group-level rating patterns and imposing user/item dependence across domains. A generative model, say ratings over site-time (ROST), which can generate and predict ratings for multiple related CF domains, is developed as the basic model for the framework. We further introduce cross-domain user/item dependence into ROST and extend it to two real-world cross-domain CF scenarios: 1) ROST (sites) for alleviating rating sparsity in the target domain, where multiple similar sites are viewed as related CF domains and some items in the target domain depend on their correspondences in the related ones; and 2) ROST (time) for modeling user-interest drift over time, where a series of time-slices are viewed as related CF domains and a user at current time-slice depends on herself in the previous time-slice. All these ROST models are instances of the proposed unified framework. The experimental results show that ROST (sites) can effectively alleviate the sparsity problem to improve rating prediction performance and ROST (time) can clearly track and visualize user-interest drift over time.

Filter bed systems treating domestic wastewater in the Nordic countries - Performance and reuse of filter media

DEFF Research Database (Denmark)

Jenssen, Petter D.; Krogstad, T.; Paruch, A.M.

2010-01-01

Nine filter beds have been constructed in the Nordic countries, Denmark, Finland, Norway and Sweden. Filter beds consist of a septic tank followed by an aerobic pre-treatment biofilter and a subsequent saturated flow grass-covered filter. Thus, filter beds are similar to subsurface flow construct...

Orientation masking and cross-orientation suppression (XOS): implications for estimates of filter bandwidth.

Science.gov (United States)

Meese, Tim S; Holmes, David J

2010-10-01

Most contemporary models of spatial vision include a cross-oriented route to suppression (masking from a broadly tuned inhibitory pool), which is most potent at low spatial and high temporal frequencies (T. S. Meese & D. J. Holmes, 2007). The influence of this pathway can elevate orientation-masking functions without exciting the target mechanism, and because early psychophysical estimates of filter bandwidth did not accommodate this, it is likely that they have been overestimated for this corner of stimulus space. Here we show that a transient 40% contrast mask causes substantial binocular threshold elevation for a transient vertical target, and this declines from a mask orientation of 0° to about 40° (indicating tuning), and then more gently to 90°, where it remains at a factor of ∼4. We also confirm that cross-orientation masking is diminished or abolished at high spatial frequencies and for sustained temporal modulation. We fitted a simple model of pedestal masking and cross-orientation suppression (XOS) to our data and those of G. C. Phillips and H. R. Wilson (1984) and found the dependency of orientation bandwidth on spatial frequency to be much less than previously supposed. An extension of our linear spatial pooling model of contrast gain control and dilution masking (T. S. Meese & R. J. Summers, 2007) is also shown to be consistent with our results using filter bandwidths of ±20°. Both models include tightly and broadly tuned components of divisive suppression. More generally, because XOS and/or dilution masking can affect the shape of orientation-masking curves, we caution that variations in bandwidth estimates might reflect variations in processes that have nothing to do with filter bandwidth.

Least median of squares filtering of locally optimal point matches for compressible flow image registration

International Nuclear Information System (INIS)

Castillo, Edward; Guerrero, Thomas; Castillo, Richard; White, Benjamin; Rojo, Javier

2012-01-01

Compressible flow based image registration operates under the assumption that the mass of the imaged material is conserved from one image to the next. Depending on how the mass conservation assumption is modeled, the performance of existing compressible flow methods is limited by factors such as image quality, noise, large magnitude voxel displacements, and computational requirements. The Least Median of Squares Filtered Compressible Flow (LFC) method introduced here is based on a localized, nonlinear least squares, compressible flow model that describes the displacement of a single voxel that lends itself to a simple grid search (block matching) optimization strategy. Spatially inaccurate grid search point matches, corresponding to erroneous local minimizers of the nonlinear compressible flow model, are removed by a novel filtering approach based on least median of squares fitting and the forward search outlier detection method. The spatial accuracy of the method is measured using ten thoracic CT image sets and large samples of expert determined landmarks (available at www.dir-lab.com). The LFC method produces an average error within the intra-observer error on eight of the ten cases, indicating that the method is capable of achieving a high spatial accuracy for thoracic CT registration. (paper)

Electrical Resistance Imaging of Bubble Boundary in Annular Two-Phase Flows Using Unscented Kalman Filter

International Nuclear Information System (INIS)

Lee, Jeong Seong; Chung, Soon Il; Ljaz, Umer Zeeshan; Khambampati, Anil Kumar; Kim, Kyung Youn; Kim, Sin Kim

2007-01-01

For the visualization of the phase boundary in annular two-phase flows, the electrical resistance tomography (ERT) technique is introduced. In ERT, a set of predetermined electrical currents is injected trough the electrodes placed on the boundary of the flow passage and the induced electrical potentials are measured on the electrode. With the relationship between the injected currents and the induced voltages, the electrical conductivity distribution across the flow domain is estimated through the image reconstruction algorithm. In this, the conductivity distribution corresponds to the phase distribution. In the application of ERT to two-phase flows where there are only two conductivity values, the conductivity distribution estimation problem can be transformed into the boundary estimation problem. This paper considers a bubble boundary estimation with ERT in annular two-phase flows. As the image reconstruction algorithm, the unscented Kalman filter (UKF) is adopted since from the control theory it is reported that the UKF shows better performance than the extended Kalman filter (EKF) that has been commonly used. We formulated the UKF algorithm to be incorporate into the image reconstruction algorithm for the present problem. Also, phantom experiments have been conducted to evaluate the improvement by UKF

Substrate Integrated Waveguide Cross-Coupling Filter with Multilayer Hexagonal Cavity

Directory of Open Access Journals (Sweden)

B. Wu

2013-01-01

Full Text Available Hexagonal cavities and their applications to multilayer substrate integrated waveguide (SIW filters are presented. The hexagonal SIW cavity which can combine flexibility of rectangular one and performance of circular one is convenient for bandpass filter’s design. Three types of experimental configuration with the same central frequency of 10 GHz and bandwidth of 6%, including three-order and four-order cross-coupling topologies, are constructed and fabricated based on low temperature cofired ceramic (LTCC technology. Both theoretical and experimental results are presented.

Computer simulation of flow ratios in a washing tower at Duesseldorf-Flingern refuse incineration plant; Computersimulation der Stroemungsverhaeltnisse in einem Waschturm der Muellverbrennungsanlage Duesseldorf-Flingern

Energy Technology Data Exchange (ETDEWEB)

Juengling, K [Technischer Ueberwachungs-Verein Rheinland e.V., Koeln (Germany); Koelle, P [Technischer Ueberwachungs-Verein Rheinland e.V., Koeln (Germany)

1997-03-01

Numeric investigations of flow ratios have been undertaken in order to optimise the operating performance of the washing towers of a refuse incineration plant during various modes of operation. On the basis of the kowledge gained from flow simulations, proposals have been developed, which have led to a significant prolongation of trouble-free operation. (orig.) [Deutsch] Zur Optimierung des Betriebsverhaltens der Waschtuerme einer Muellverbrennungsanlage bei unterschiedlichen Fahrweisen wurden numerische Untersuchungen der Stroemungsverhaeltnisse durchgefuehrt. Aufgrund der Erkenntnisse aus den Stroemungssimulationen wurden Vorschlaege entwickelt, die zu einer deutlichen Verlaengerung des stoerungsfreien Betriebs fuehrten. (orig.)

A volume-filtered formulation to capture particle-shock interactions in multiphase compressible flows

Science.gov (United States)

Shallcross, Gregory; Capecelatro, Jesse

2017-11-01

Compressible particle-laden flows are common in engineering systems. Applications include but are not limited to water injection in high-speed jet flows for noise suppression, rocket-plume surface interactions during planetary landing, and explosions during coal mining operations. Numerically, it is challenging to capture these interactions due to the wide range of length and time scales. Additionally, there are many forms of the multiphase compressible flow equations with volume fraction effects, some of which are conflicting in nature. The purpose of this presentation is to develop the capability to accurately capture particle-shock interactions in systems with a large number of particles from dense to dilute regimes. A thorough derivation of the volume filtered equations is presented. The volume filtered equations are then implemented in a high-order, energy-stable Eulerian-Lagrangian framework. We show this framework is capable of decoupling the fluid mesh from the particle size, enabling arbitrary particle size distributions in the presence of shocks. The proposed method is then assessed against particle-laden shock tube data. Quantities of interest include fluid-phase pressure profiles and particle spreading rates. The effect of collisions in 2D and 3D are also evaluated.

Effects of filtering methods on muscle and fat cross-sectional area measurement by pQCT: a technical note

International Nuclear Information System (INIS)

Sherk, Vanessa D; Bemben, Michael G; Palmer, Ian J; Bemben, Debra A

2011-01-01

Peripheral quantitative computed tomography (pQCT) is most commonly used for bone density and morphology assessment of the limbs, but it can also be used for soft tissue area quantification by segmenting regions representing different tissues. Scanning and analyzing cross-sectional areas of larger thighs present a special challenge due to increased statistical noise created from fewer detected x-ray photons. The purpose of this technical note is to compare total, muscle and fat cross-sectional area (CSA) measurements of the midthigh with Stratec 3000 pQCT scans using no filter, a weak smoothing filter and a strong smoothing filter to CSA measurements of midthigh MRI scans analyzed by Image J, a public domain image processing program. Nine healthy men and women participated in this study. CSAs did not differ significantly between MRI and strongly filtered pQCT images with per cent differences ranging from −3.1% for muscle to +6.5% for fat. The per cent difference in muscle CSA values between MRI and pQCT with the weak filter (−24.0 ± 38.0%) or no filter (−44.9 ± 22.7%) was strongly related to total thigh CSA (r = 0.78–0.92, p < 0.05). We propose that the midthigh can be assessed for soft tissue area measurements with pQCT, provided that strong smoothing filter is utilized. (note)

Application of Self Cleaning Rapid Sand Filter in Water Treatment

Directory of Open Access Journals (Sweden)

Ali Reza Rahmani

2005-08-01

Full Text Available Rapid sand filter is one of the most important units in the water treatment plants. It has some difficulties in operation such as backwashing. For the solving of this problem a rapid sand filter has designed and built with the self-cleaning backwashing system. This system consist of 3 main constituents; one galvanized siphon and two galvanized steel tanks. One of them is used for filtration and the other used for the storage of filtrated water in elevation for backwashing the system. Water enter from upside of the filter through the inlet pipe, and collected from the under drainage pipe. Then filter water conduct to the storage tank and exit from outlet pipe. In the beginning, the head loss was low, but because of bed clogging by suspended solids, it increases gradually to the designed head loss (1.2m. Then the system is outed of the service automatically and the backwash is began. The main data for the design of system selected from the hydraulic rules of siphons and rapid sand filter criteria. After essential calculations it was constructed and was started operation. For the hydraulic studies a known volume of storage tank was selected and the time needed for the fill (in filtration stage and empty (in backwash stage of water volume with volumetric method were measured. In hydraulic studies the filter surface rate (SOR was selected about 5-7.5m3/m2/hr (1.39-2.08 lit/sec and the flow of water in siphon, during the backwashing was measured 8.7 lit/sec. It can be seen that the siphon passes 4-6 times the inlet raw water thus a negative pressure will created in the siphon which causes the water above the sand bed to be discharged automatically and rinse water from elevated tank flow under the sand bed and back wash it. So according to this study self cleaning rapid sand filter is very useful for water filtration, especially in small population community. The construction of system is rapid, simple and economic.

A Cross-Domain Collaborative Filtering Algorithm Based on Feature Construction and Locally Weighted Linear Regression.

Science.gov (United States)

Yu, Xu; Lin, Jun-Yu; Jiang, Feng; Du, Jun-Wei; Han, Ji-Zhong

2018-01-01

Cross-domain collaborative filtering (CDCF) solves the sparsity problem by transferring rating knowledge from auxiliary domains. Obviously, different auxiliary domains have different importance to the target domain. However, previous works cannot evaluate effectively the significance of different auxiliary domains. To overcome this drawback, we propose a cross-domain collaborative filtering algorithm based on Feature Construction and Locally Weighted Linear Regression (FCLWLR). We first construct features in different domains and use these features to represent different auxiliary domains. Thus the weight computation across different domains can be converted as the weight computation across different features. Then we combine the features in the target domain and in the auxiliary domains together and convert the cross-domain recommendation problem into a regression problem. Finally, we employ a Locally Weighted Linear Regression (LWLR) model to solve the regression problem. As LWLR is a nonparametric regression method, it can effectively avoid underfitting or overfitting problem occurring in parametric regression methods. We conduct extensive experiments to show that the proposed FCLWLR algorithm is effective in addressing the data sparsity problem by transferring the useful knowledge from the auxiliary domains, as compared to many state-of-the-art single-domain or cross-domain CF methods.

A novel reverse-osmosis wash water recycle system for manned space stations

Science.gov (United States)

Ray, R. J.; Babcock, W. C.; Barss, R. P.; Andrews, T. A.; Lachapelle, E. D.

1984-01-01

The preliminary development of a wash water recycle system utilizing an inside-skinned hollow-fiber membrane is described. This module configuration is based on tube-side feed and is highly resistant to fouling with a minimum of pretreatment. During an ongoing research program for NASA, these modules were operated on actual wash waters with no significant fouling for a period of 40 days. Due to the tube-side-feed flow in these hollow-fiber membranes, the fibers themselves become the pressure vessels, allowing the development of extremely lightweight membrane modules. During the NASA research program, a pre-prototype membrane module capable of processing 6 gallons per day of wash water at 97 percent recovery was developed that can be dry-stored and that weighs 120 g.

Experimental–theoretical methodology for determination of inertial pressure drop distribution and pore structure properties in wall-flow diesel particulate filters (DPFs)

International Nuclear Information System (INIS)

Payri, F.; Broatch, A.; Serrano, J.R.; Piqueras, P.

2011-01-01

Wall-flow particulate filters have been placed as a standard technology for Diesel engines because of the increasing restrictions to soot emissions. The inclusion of this system within the exhaust line requires the development of computational tools to properly simulate its flow dynamics and acoustics behaviour. These aspects become the key to understand the influence on engine performance and driveability as a function of the filter placement. Since the pressure drop and the filtration process are strongly depending on the pore structure properties – permeability, porosity and pore size – a reliable definition of these characteristics is essential for model development. In this work a methodology is proposed to determine such properties based on the combination of the pressure drop rement in a steady flow test rig and two theoretical approaches. The later are a lumped model and a one-dimensional (1D) unsteady compressible flow model. The purpose is to simplify the integration of particulate filters into the global engine modelling and development processes avoiding the need to resort to specific and expensive characterisation tests. The proposed methodology was validated against measurements of the response of an uncoated diesel particulate filter (DPF) under different flow conditions as cold steady flow, impulsive flow and hot pulsating flow. -- Highlights: ► Experimental and modelling tools to characterise wall-flow DPFs pressure drop. ► Decomposition of inertial pressure drop contributions in canned DPFs. ► Methodology to define pore structure properties in clean wall-flow DPFs. ► Evaluation of specific permeability, porosity and mean pore diameter. ► Significant influence of slip-flow effect on uncoated wall-flow DPFs.

Effects of household washing on bacterial load and removal of Escherichia coli from lettuce and "ready-to-eat" salads.

Science.gov (United States)

Uhlig, Elisabeth; Olsson, Crister; He, Jiayi; Stark, Therese; Sadowska, Zuzanna; Molin, Göran; Ahrné, Siv; Alsanius, Beatrix; Håkansson, Åsa

2017-11-01

Customer demands for fresh salads are increasing, but leafy green vegetables have also been linked to food-borne illness due to pathogens such as Escherichia coli O157:H7. As a safety measure, consumers often wash leafy vegetables in water before consumption. In this study, we analyzed the efficiency of household washing to reduce the bacterial content. Romaine lettuce and ready-to-eat mixed salad were washed several times in flowing water at different rates and by immersing the leaves in water. Lettuce was also inoculated with E. coli before washing. Only washing in a high flow rate (8 L/min) resulted in statistically significant reductions ( p  < .05), "Total aerobic count" was reduced by 80%, and Enterobacteriaceae count was reduced by 68% after the first rinse. The number of contaminating E. coli was not significantly reduced. The dominating part of the culturable microbiota of the washed lettuce was identified by rRNA 16S sequencing of randomly picked colonies. The majority belonged to Pseudomonadaceae , but isolates from Enterobacteriaceae and Staphylococcaceaceae were also frequently found. This study shows the inefficiency of tap water washing methods available for the consumer when it comes to removal of bacteria from lettuce. Even after washing, the lettuce contained high levels of bacteria that in a high dose and under certain circumstances may constitute a health risk.

Selected hydrologic data from Fortymile Wash in the Yucca Mountain area, Nevada, water years 1993--94

Energy Technology Data Exchange (ETDEWEB)

Savard, C.S.

1996-09-01

The Yucca Mountain area is being evaluated by the US Department of Energy for its suitability to store high-level nuclear waste in a mined, underground repository. Hydrologic data are being collected by the US Geological Survey throughout a 150 Km{sup 2} study area about 15- Km northwest of Las Vegas in southern Nevada for site characterization studies. Ongoing hydrologic studies are investigating atmospheric precipitation, stream-flow, movement of water through the unsaturated zone, movement of water through the saturated zone, and paleohydrology. This study at Fortymile Wash involves some components of each of these studies. Fortymile Wash is an ephemeral stream near Yucca Mountain with tributaries draining the east side of Yucca Mountain and then forming a distributary system in the Amargosa Desert. An objective of the study is to determine the amount of recharge from Fortymile Wash to the ground-water flow system that has been proposed. Understanding the ground-water flow system is important because it is a possible mechanism for radionuclide migration from the repository to the accessible environment. An adequate understanding of the ground-water flow system is necessary for an evaluation of the safety issues involved in siting the potential repository.

Flow behaviour and robustness of non-segregating tailings made from filtered/centrifuged MFT

Energy Technology Data Exchange (ETDEWEB)

Nik, R.M.; Sego, D.C.; Morgenstern, N.R. [Alberta Univ., Edmonton, AB (Canada). Geotechnical Center

2010-07-01

This PowerPoint presentation described an experimental study of a centrifugal dewatering filtration process for mature fine tailings (MFT). Various MFT samples from different oil sands operations were pumped into a filtering centrifuge that produced cake, thin tailings, and filtrate. The MFT was then transformed into non-segregated tailings (NST) and composite tailings (CT). The depositional characteristics of the CT-NST samples were evaluated in a series of flume tests. Flow profiles were presented for various samples. Vane shear tests were also conducted. The yield stress of each sample was compared with its flow duration and solids content. The results of the experimental tests demonstrated that the centrifugal filtration process can be considered as the initial stage of a multi-stage tailings management plan. The filtering centrifuge method can be used to produce robust CTs with higher solids content. Use of the method can decrease the amount of coagulants or flocculants required for further treatment. tabs., figs.

A flow-based methodology for the calculation of TSO to TSO compensations for cross-border flows

International Nuclear Information System (INIS)

Glavitsch, H.; Andersson, G.; Lekane, Th.; Marien, A.; Mees, E.; Naef, U.

2004-01-01

In the context of the development of the European internal electricity market, several methods for the tarification of cross-border flows have been proposed. This paper presents a flow-based method for the calculation of TSO to TSO compensations for cross-border flows. The basic principle of this approach is the allocation of the costs of cross-border flows to the TSOs who are responsible for these flows. This method is cost reflective, non-transaction based and compatible with domestic tariffs. It can be applied when limited data are available. Each internal transmission network is then modelled as an aggregated node, called 'supernode', and the European network is synthesized by a graph of supernodes and arcs, each arc representing all cross-border lines between two adjacent countries. When detailed data are available, the proposed methodology is also applicable to all the nodes and lines of the transmission network. Costs associated with flows transiting through supernodes or network elements are forwarded through the network in a way reflecting how the flows make use of the network. The costs can be charged either towards loads and exports or towards generations and imports. Combination of the two charging directions can also be considered. (author)

Explaining low rates of sustained use of siphon water filter: evidence from follow-up of a randomised controlled trial in Bangladesh.

Science.gov (United States)

Najnin, Nusrat; Arman, Shaila; Abedin, Jaynal; Unicomb, Leanne; Levine, David I; Mahmud, Minhaj; Leder, Karin; Yeasmin, Farzana; Luoto, Jill E; Albert, Jeff; Luby, Stephen P

2015-04-01

To assess sustained siphon filter usage among a low-income population in Bangladesh and study relevant motivators and barriers. After a randomised control trial in Bangladesh during 2009, 191 households received a siphon water filter along with educational messages. Researchers revisited households after 3 and 6 months to assess filter usage and determine relevant motivators and barriers. Regular users were defined as those who reported using the filter most of the time and were observed to be using the filter at follow-up visits. Integrated behavioural model for water, sanitation and hygiene (IBM-WASH) was used to explain factors associated with regular filter use. Regular filter usage was 28% at the 3-month follow-up and 21% at the 6-month follow-up. Regular filter users had better quality water at the 6-month, but not at the 3-month visit. Positive predictors of regular filter usage explained through IBM-WASH at both times were willingness to pay >US$1 for filters, and positive attitude towards filter use (technology dimension at individual level); reporting boiling drinking water at baseline (psychosocial dimension at habitual level); and Bengali ethnicity (contextual dimension at individual level). Frequently reported barriers to regular filter use were as follows: considering filter use an additional task, filter breakage and time required for water filtering (technology dimension at individual level). The technological, psychosocial and contextual dimensions of IBM-WASH contributed to understanding the factors related to sustained use of siphon filter. Given the low regular usage rate and the hardware-related problems reported, the contribution of siphon filters to improving water quality in low-income urban communities in Bangladesh is likely to be minimal. © 2014 John Wiley & Sons Ltd.

Two models for the dynamics of a cross flow heat exchanger

Energy Technology Data Exchange (ETDEWEB)

Hopkinson, A [Control and Instrumentation Division, Atomic Energy Establishment, Winfrith, Dorchester, Dorset (United Kingdom)

1962-12-15

Two models of a cross flow heat exchanger, a concentric tube counter flow model and a cross flow model, are studied theoretically. Differential equations describing the behaviour of the models are derived and from them equations for the steady state temperatures and the temperature transfer functions are obtained. (author)

CVVHD treatment with CARPEDIEM: small solute clearance at different blood and dialysate flows with three different surface area filter configurations.

Science.gov (United States)

Lorenzin, Anna; Garzotto, Francesco; Alghisi, Alberta; Neri, Mauro; Galeano, Dario; Aresu, Stefania; Pani, Antonello; Vidal, Enrico; Ricci, Zaccaroa; Murer, Luisa; Goldstein, Stuart L; Ronco, Claudio

2016-10-01

The CARdiorenal PEDIatric EMergency (CARPEDIEM) machine was originally designed to perform only continuous venovenous hemofiltration (CVVH) in neonatal and pediatric patients. In some cases, adequate convective clearance may not be reached because of a limited blood flow. In such conditions, the application of diffusive clearance [continuous venovenous hemodialysis (CVVHD)] would help optimize blood purification. In this study, the CARPEDIEM™ machine was modified to enable the circulation of dialysis through the filter allowing testing of the performance of CARPEDIEM™ machine in CVVHD. Three different polyethersulfone hemodialyzers (surface area = 0.1 m(2), 0.2 m(2), and 0.35 m(2), respectively) were tested in vitro with a scheduled combination of plasma flow rates (Qp = 10-20-30 ml/min) and dialysis fluid flow rate (Qd = 5-10-15 ml/min). Three sessions were performed in co-current and one in counter-current configuration (as control) for each filter size. Clearance was measured from the blood and dialysate sides and results with mass balance error greater than 5 % were discarded. Urea and creatinine clearances for each plasma/dialysate combination are reported: clearance increase progressively for every filter proportionally to plasma flow rates. Similarly, clearances increase progressively with dialysate flow rates at a given plasma flow. The clearance curve tends to present a steep increase for small increases in plasma flow in the range below 10 ml/min, while the curve tends to plateau for values averaging 30 ml/min. As expected, the plateau is reached earlier with the smaller filter showing the effect of membrane surface-area limitation. At every plasma flow, the effect of dialysate flow increase is evident and well defined, showing that saturation of effluent was not achieved completely in any of the experimental conditions explored. No differences (p > 0.05 for all values) were obtained in experiments using whole blood instead of

A Cluster Randomized Controlled Trial to Reduce Childhood Diarrhea Using Hollow Fiber Water Filter and/or Hygiene–Sanitation Educational Interventions

Science.gov (United States)

Lindquist, Erik D.; George, C. M.; Perin, Jamie; Neiswender de Calani, Karen J.; Norman, W. Ray; Davis, Thomas P.; Perry, Henry

2014-01-01

Safe domestic potable water supplies are urgently needed to reduce childhood diarrheal disease. In periurban neighborhoods in Cochabamba, Bolivia, we conducted a cluster randomized controlled trial to evaluate the efficacy of a household-level hollow fiber filter and/or behavior change communication (BCC) on water, sanitation, and hygiene (WASH) to reduce the diarrheal disease in children less than 5 years of age. In total, 952 households were followed for a period of 12 weeks post-distribution of the study interventions. Households using Sawyer PointONE filters had significantly less diarrheal disease compared with the control arm during the intervention period, which was shown by diarrheal prevalence ratios of 0.21 (95% confidence interval [95% CI] = 0.15–0.30) for the filter arm and 0.27 (95% CI = 0.22–0.34) for the filter and WASH BCC arm. A non-significant reduction in diarrhea prevalence was reported in the WASH BCC study arm households (0.71, 95% CI = 0.59–0.86). PMID:24865680

Device for filtering gaseous media

International Nuclear Information System (INIS)

Benzel, M.

1978-01-01

The air filter system for gaseous radioactive substances consists of a vertical chamber with filter material (charcoal, e.g. impregnated). On one side of the chamber there is an inlet compartment and an outlet compartment. On the other side a guiding compartment turns the gas flow coming from the natural-air side through the lower part of filter chamber to the upper part of the filter. The gas flow leaves the upper part through the outlet conpartment as cleaned-air flow. The filter material may be filled into the chamber from above and drawn off below. For better utilization of the filter material the filter chamber is separated by means of a wall between the inlet and outlet compartment. This partition wall consist of two sheets arranged one above the other provided with slots which may be superposed in alignment. In this case filter material is tickling from the upper part of the chamber into the lower part avoiding to form a crater in the filter bed. (DG) [de

CrossFlow: integrating workflow management and electronic commerce

NARCIS (Netherlands)

Hoffner, Y.; Ludwig, H.; Grefen, P.W.P.J.; Aberer, K.

2001-01-01

The CrossFlow architecture provides support for cross-organisational workflow management in dynamically established virtual enterprises. The creation of a business relationship between a service provider organisation performing a service on behalf of a consumer organisation can be made dynamic when

Assessment of crushed-recycled glass as filter media for drinking water treatment

International Nuclear Information System (INIS)

Rutledge, S.O.; Fahie, C.; Gagnon, G.A.

2002-01-01

The objective of this project was to evaluate the performance of a pressure filter utilizing crushed glass as the filter media. The performance of the crushed glass filter was compared to that of a sand filter. The research was conducted in Orangedale, Nova Scotia, which is a small community of with a population of approximately 500. Orangedale is located on the south shore of Bras d'Or Lakes and feeds into Miller Pond, which serves as the source the of drinking water. The Orangedale treatment plant produces an average daily flow of 35 m3/d (6.4-gpm). The treatment plant consists of coagulation (sodium aluminate and polyaluminum chloride), flocculation, dissolved air flotation (DAF), disinfection with sodium hypochlorite and dual-media filtration with anthracite and sand. In general, the particle removal capabilities of the crushed glass filter were slightly poorer than that of a sand filter, as quantified in a field application in the community of Orangedale, Nova Scotia. It was found that the crushed glass used in this project had a higher angularity and slightly higher uniformity coefficient. During initial start-up the performance of the crushed glass filter was more variable and appeared to improve as the glass began to wear. After six-months of use the crushed glass filter was able to produce a very consistent filter effluent that was only slightly greater than the silica sand filter. After six-months of use, the sand filter achieved a 1.6 log-removal of particles with diameters greater than 2 μm; whereas the crushed glass filter achieved a 1.4 log removal for the similar particle size range. The observed removal performance was particularly encouraging given that the sand used had properties that were consistent with the standards set by the American Water Works Association. The crushed glass filter media was initially sieved and washed, but had no other pre-treatment preparation. Thus the application of crushed glass shows considerable promise as filter

Effect of the spatial filtering and alignment error of hot-wire probes in a wall-bounded turbulent flow

International Nuclear Information System (INIS)

Segalini, A; Cimarelli, A; Rüedi, J-D; De Angelis, E; Talamelli, A

2011-01-01

The effort to describe velocity fluctuation distributions in wall-bounded turbulent flows has raised different questions concerning the accuracy of hot-wire measurement techniques close to the wall and more specifically the effect of spatial averaging resulting from the finite size of the wire. Here, an analytical model which describes the effect of the spatial filtering and misalignment of hot-wire probes on the main statistical moments in turbulent wall-bounded flows is presented. The model, which is based on the two-point velocity correlation function, shows that the filtering is directly related to the transverse Taylor micro-scale. By means of turbulent channel flow DNS data, the capacity of the model to accurately describe the probe response is established. At the same time, the filtering effect is appraised for different wire lengths and for a range of misalignment angles which can be expected from good experimental practice. Effects of the second-order terms in the model equations are also taken into account and discussed. In order to use the model in a practical situation, the Taylor micro-scale distribution at least should be provided. A simple scaling law based on classic turbulence theory is therefore introduced and finally employed to estimate the filtering effect for different wire lengths

Measurement of 24.3 keV activation cross sections with the iron filter technique

International Nuclear Information System (INIS)

Rimawi, K.; Chrien, R.E.

1975-01-01

By using high-resolution detection techniques, intensities of specific activation lines from 197 Au(n,gamma), 238 U(n,gamma), 127 I(n,gamma), and 115 In(n,gamma) [54 min + 2.2 sec] were recorded, by using the BNL HFBR iron-filtered neutron beam. From a com- parison with the reaction 10 B(n,αgamma), cross sections at 24.3 keV were determined. (24.3 keV neutron activation cross sections, relative 10 B standard). (4 figures) (U.S.)

A Study on the Uncertainty of Flow-Induced Vibration in a Cross Flow over Staggered Tubes

Energy Technology Data Exchange (ETDEWEB)

Kim, Ji-Su; Park, Jong-Woon [Dongguk univ, Gyeong Ju (Korea, Republic of); Choi, Hyeon-Kyeong [HanNam University, Daejeon (Korea, Republic of)

2015-05-15

Cross-flow in many support columns of very high temperature reactor (VHTR) lower plenum would have FIV issues under high speed flow jetting from the core. For a group of multiple circular cylinders subjected to a cross-flow, three types of potential vibration mechanisms may exist: (1) Vortex-induced vibration (VIV), (2) Fluid-elastic vibration (FEV) and (3) Turbulence-induced vibration (TIV). Kevalahan studied the free vibration of circular cylinders in a tightly packed periodic square inline array of cylinders. Pandey et al. studied the flue gas flow distribution in the Low Temperature Super Heater (LTSH) tube bundles situated in second pass of a utility boiler and the phenomenon of flow induced vibration. Nakamura et al. studied flow instability of cylinder arrays resembling U-bend tubes in steam generators. The FIV evaluation is usually performed with computational fluid dynamic (CFD) analysis to obtain unknown frequency of oscillation of the multiple objects under turbulent flow and thus the uncertainty residing in the turbulence model used should be quantified. In this paper, potential FIV uncertainty arising from the turbulence phenomena are evaluated for a typical cross flow through staggered tube bundles resembling the VHTR lower plenum support columns. Flow induced vibration (FIV) is one of the important mechanical and fatigue issues in nuclear systems. Especially, cross-flow in many support structures of VHTR lower plenum would have FIV issues under highly turbulent jet flows from the core. The results show that the effect of turbulence parameters on FIV is not negligible and the uncertainty is 5 to 10%. Present method can be applied to future FIV evaluations of nuclear systems. More extensive studies on flow induced vibration in a plant scale by using more rigorous computational methods are under way.

OPTICAL CROSS-CORRELATION FILTERS: AN ECONOMICAL APPROACH FOR IDENTIFYING SNe Ia AND ESTIMATING THEIR REDSHIFTS

International Nuclear Information System (INIS)

Scolnic, Daniel M.; Riess, Adam G.; Huber, Mark E.; Rest, Armin; Stubbs, Christoper W.; Tonry, John L.

2009-01-01

Large photometric surveys of transient phenomena, such as Panoramic Survey Telescope and Rapid Response System and Large Synoptic Survey Telescope, will locate thousands to millions of Type Ia supernova (SN Ia) candidates per year, a rate prohibitive for acquiring spectroscopy to determine each candidate's type and redshift. In response, we have developed an economical approach to identifying SNe Ia and their redshifts using an uncommon type of optical filter which has multiple, discontinuous passbands on a single substrate. Observation of a supernova through a specially designed pair of these 'cross-correlation filters' measures the approximate amplitude and phase of the cross-correlation between the spectrum and a SN Ia template, a quantity typically used to determine the redshift and type of a high-redshift SN Ia. Simulating the use of these filters, we obtain a sample of SNe Ia which is ∼98% pure with individual redshifts measured to σ z = 0.01 precision. The advantages of this approach over standard broadband photometric methods are that it is insensitive to reddening, independent of the color data used for subsequent distance determinations which reduce selection or interpretation bias, and because it makes use of the spectral features its reliability is greater. A great advantage over long-slit spectroscopy comes from increased throughput, enhanced multiplexing, and reduced setup time resulting in a net gain in speed of up to ∼30 times. This approach is also insensitive to host galaxy contamination. Prototype filters were built and successfully used on Magellan with LDSS-3 to characterize three SuperNova Legacy Survey candidates. We discuss how these filters can provide critical information for the upcoming photometric supernova surveys.

LHCb Kalman Filter cross architecture studies

Science.gov (United States)

Hugo, Daniel; Pérez, Cámpora

2017-10-01

The 2020 upgrade of the LHCb detector will vastly increase the rate of collisions the Online system needs to process in software, in order to filter events in real time. 30 million collisions per second will pass through a selection chain, where each step is executed conditional to its prior acceptance. The Kalman Filter is a fit applied to all reconstructed tracks which, due to its time characteristics and early execution in the selection chain, consumes 40% of the whole reconstruction time in the current trigger software. This makes the Kalman Filter a time-critical component as the LHCb trigger evolves into a full software trigger in the Upgrade. I present a new Kalman Filter algorithm for LHCb that can efficiently make use of any kind of SIMD processor, and its design is explained in depth. Performance benchmarks are compared between a variety of hardware architectures, including x86_64 and Power8, and the Intel Xeon Phi accelerator, and the suitability of said architectures to efficiently perform the LHCb Reconstruction process is determined.

Use of cross-flow membrane filtration in a recirculating hydroponic system to suppress root disease in pepper caused by Pythium myriotylum.

Science.gov (United States)

Schuerger, Andrew C; Hammer, William

2009-05-01

Zoosporic pathogens in the genera Pythium and Phytophthora cause extensive root disease epiphytotics in recirculating hydroponic vegetable-production greenhouses. Zoospore cysts of Pythium myriotylum Drechsler were used to evaluate the effectiveness of cross-flow membrane filters to control pythiaceous pathogens in recirculating hydroponic systems. Four membrane filter brands (Honeycomb, Polypure, Polymate, and Absolife) were tested alone or in combination to determine which filters would effectively remove infective propagules of P. myriotylum from solutions and reduce disease incidence and severity. Zoospore cysts of P. myriotylum generally measured 8 to 10 microm, and it was hypothesized that filters with pore-sizespepper plants from root infection. Single-filter assays with Honeycomb and Polypure brands removed 85 to 95% of zoospore cysts when pore sizes were rated at 1, 5, 10, 20, or 30 microm. Single-filter assays of Polymate and Absolife brands were more effective, exhibiting apparently 100% removal of zoospore cysts from nutrient solutions on filters rated at 1 to 10 microm. However, plant bioassays with Honeycomb and Polymate single filters failed to give long-term protection of pepper plants. Double-filter assays with 1- and 0.5-microm Polymate filters significantly increased the protection of pepper plants grown in nutrient film technique systems but, eventually, root disease and plant wilt could be observed. Insect transmissions by shore flies were not factors in disease development. Scanning electron microscopy images of zoospore cysts entrapped on Polymate filters revealed zoospore cysts that were either fully encysted, partially encysted, or of unusually small size (3 microm in diameter). It was concluded that either the atypically small or pliable pleomorphic zoospore cysts were able to penetrate filter membranes that theoretically should have captured them.

Study on performance and flow field of an undershot cross-flow water turbine comprising different number of blades

Science.gov (United States)

Nishi, Yasuyuki; Hatano, Kentaro; Inagaki, Terumi

2017-10-01

Recently, small hydroelectric generators have gained attention as a further development in water turbine technology for ultra low head drops in open channels. The authors have evaluated the application of cross-flow water turbines in open channels as an undershot type after removing the casings and guide vanes to substantially simplify these water turbines. However, because undershot cross-flow water turbines are designed on the basis of cross-flow water turbine runners used in typical pipelines, it remains unclear whether the number of blades has an effect on the performance or flow fields. Thus, in this research, experiments and numerical analyses are employed to study the performance and flow fields of undershot cross-flow water turbines with varying number of blades. The findings show that the turbine output and torque are lower, the fluctuation is significantly higher, and the turbine efficiency is higher for runners with 8 blades as opposed to those with 24 blades.

On the Impact of Particulate Matter Distribution on Pressure Drop of Wall-Flow Particulate Filters

Directory of Open Access Journals (Sweden)

Vicente Bermúdez

2017-03-01

Full Text Available Wall-flow particulate filters are a required exhaust aftertreatment system to abate particulate matter emissions and meet current and incoming regulations applying worldwide to new generations of diesel and gasoline internal combustion engines. Despite the high filtration efficiency covering the whole range of emitted particle sizes, the porous substrate constitutes a flow restriction especially relevant as particulate matter, both soot and ash, is collected. The dependence of the resulting pressure drop, and hence the fuel consumption penalty, on the particulate matter distribution along the inlet channels is discussed in this paper taking as reference experimental data obtained in water injection tests before the particulate filter. This technique is demonstrated to reduce the particulate filter pressure drop without negative effects on filtration performance. In order to justify these experimental data, the characteristics of the particulate layer are diagnosed applying modeling techniques. Different soot mass distributions along the inlet channels are analyzed combined with porosity change to assess the new properties after water injection. Their influence on the subsequent soot loading process and regeneration is assessed. The results evidence the main mechanisms of the water injection at the filter inlet to reduce pressure drop and boost the interest for control strategies able to force the re-entrainment of most of the particulate matter towards the inlet channels’ end.

Void fraction measurement in two-phase flow processes via symbolic dynamic filtering of ultrasonic signals

International Nuclear Information System (INIS)

Chakraborty, Subhadeep; Keller, Eric; Talley, Justin; Srivastav, Abhishek; Ray, Asok; Kim, Seungjin

2009-01-01

This communication introduces a non-intrusive method for void fraction measurement and identification of two-phase flow regimes, based on ultrasonic sensing. The underlying algorithm is built upon the recently reported theory of a statistical pattern recognition method called symbolic dynamic filtering (SDF). The results of experimental validation, generated on a laboratory test apparatus, show a one-to-one correspondence between the flow measure derived from SDF and the void fraction measured by a conductivity probe. A sharp change in the slope of flow measure is found to be in agreement with a transition from fully bubbly flow to cap-bubbly flow. (rapid communication)

CrossFlow: Integrating Workflow Management and Electronic Commerce

NARCIS (Netherlands)

Hoffner, Y.; Ludwig, H.; Grefen, P.W.P.J.; Aberer, K.

2001-01-01

The CrossFlow1 architecture provides support for cross-organisational workflow management in dynamically established virtual enterprises. The creation of a business relationship between a service provider organisation performing a service on behalf of a consumer organisation can be made dynamic when

A Cross-Domain Collaborative Filtering Algorithm Based on Feature Construction and Locally Weighted Linear Regression

Directory of Open Access Journals (Sweden)

Xu Yu

2018-01-01

Full Text Available Cross-domain collaborative filtering (CDCF solves the sparsity problem by transferring rating knowledge from auxiliary domains. Obviously, different auxiliary domains have different importance to the target domain. However, previous works cannot evaluate effectively the significance of different auxiliary domains. To overcome this drawback, we propose a cross-domain collaborative filtering algorithm based on Feature Construction and Locally Weighted Linear Regression (FCLWLR. We first construct features in different domains and use these features to represent different auxiliary domains. Thus the weight computation across different domains can be converted as the weight computation across different features. Then we combine the features in the target domain and in the auxiliary domains together and convert the cross-domain recommendation problem into a regression problem. Finally, we employ a Locally Weighted Linear Regression (LWLR model to solve the regression problem. As LWLR is a nonparametric regression method, it can effectively avoid underfitting or overfitting problem occurring in parametric regression methods. We conduct extensive experiments to show that the proposed FCLWLR algorithm is effective in addressing the data sparsity problem by transferring the useful knowledge from the auxiliary domains, as compared to many state-of-the-art single-domain or cross-domain CF methods.

Experimental Investigation on Cross Flow of Wedge-shaped Gap in the core of Prismatic VHTR

International Nuclear Information System (INIS)

Lee, Jeong Hun; Park, Goon Cherl; Cho, Hyoung Kyu; Yoon, Su Jong

2014-01-01

The core of the PMR type reactor consists of assemblies of hexagonal graphite blocks. The graphite blocks have lots of advantages for neutron economy and high temperature structural integrity. The height and flat-to-flat width of fuel bock are 793 mm and 360 mm, respectively. Each block has 108 coolant channels of which the diameter is 16 mm. And there are gaps between blocks not only vertically but also horizontally for reloading of the fuel elements. The vertical gap induces the bypass flow and through the horizontal gap the cross flow is formed. Since the complicated flow distribution occurs by the bypass flow and cross flow, flow characteristics in the core of the PMR reactor cannot be treated as a simple pipe flow. The fuel zone of the PMR core consists of multiple layers of fuel blocks. The shape change of the fuel blocks could be caused by the thermal expansion and fast-neutron induced shrinkage. It could make different axial shrinkage of fuel block and this leads to wedge-shaped gaps between two stacked fuel blocks. The cross flow is often considered as a leakage flow through the horizontal gap between stacked fuel blocks and it complicates the flow distribution in the reactor core by connecting the coolant channel and the bypass gap. Moreover, the cross flow could lead to uneven coolant distribution and consequently cause superheating of individual fuel element zones with increased fission product release. Since the core cross flow has a negative impact on safety and efficiency of VHTR, core cross flow phenomena have to be investigated to improve the core thermal margin of VHTR. To develop the cross flow loss coefficient model for determination of the flow distribution for PMR core analysis codes, study on cross flow for PMR200 core is essential. In particular, to predict the amount of flow through the cross flow gap, obtaining accurate flow loss coefficient is important. In this study, the full-scale cross flow experimental facility was constructed to

Removal of PCR inhibitors using dielectrophoresis as a selective filter in a microsystem

DEFF Research Database (Denmark)

Perch-Nielsen, Ivan Ryberg; Bang, Dang Duong; Poulsen, Claus Riber

2003-01-01

, the removal of PCR inhibitors in sample preparation steps is essential and several methods have been published. The methods are either chemical or based on filtering. Conventional ways of filtering include mechanical filters or washing e. g. by centrifugation. Another way of filtering is the use of electric...... to manipulate cells in many microstructures. In this study, we used DEP as a selective filter for holding cells in a microsystem while the PCR inhibitors were flushed out of the system. Haemoglobin and heparin-natural components of blood-were selected as PCR inhibitors, since the inhibitory effects...

Filter-extruded liposomes revisited

DEFF Research Database (Denmark)

Hinna, Askell; Steiniger, Frank; Hupfeld, Stefan

2016-01-01

(pore-size, number of filter passages, and flow-rate), flow field-flow fractionation in conjunction with multi-angle laser light scattering (AF4-MALLS, Wyatt Technology Corp., Santa Barbara, CA) was employed. Liposome size-distributions determined by AF4-MALLS were compared with those of dynamic light...... is suggested to prepare large (300 nm) liposomes with rather narrow size distribution, based on the filter extrusion at defined flow-rates in combination with freeze-/ thaw-cycling and bench-top centrifugation....

Effect of Post-Reconstruction Gaussian Filtering on Image Quality and Myocardial Blood Flow Measurement with N-13 Ammonia PET

Directory of Open Access Journals (Sweden)

Hyeon Sik Kim

2014-10-01

Full Text Available Objective(s: In order to evaluate the effect of post-reconstruction Gaussian filtering on image quality and myocardial blood flow (MBF measurement by dynamic N-13 ammonia positron emission tomography (PET, we compared various reconstruction and filtering methods with image characteristics. Methods: Dynamic PET images of three patients with coronary artery disease (male-female ratio of 2:1; age: 57, 53, and 76 years were reconstructed, using filtered back projection (FBP and ordered subset expectation maximization (OSEM methods. OSEM reconstruction consisted of OSEM_2I, OSEM_4I, and OSEM_6I with 2, 4, and 6 iterations, respectively. The images, reconstructed and filtered by Gaussian filters of 5, 10, and 15 mm, were obtained, as well as non-filtered images. Visual analysis of image quality (IQ was performed using a 3-grade scoring system by 2 independent readers, blinded to the reconstruction and filtering methods of stress images. Then, signal-to-noise ratio (SNR was calculated by noise and contrast recovery (CR. Stress and rest MBF and coronary flow reserve (CFR were obtained for each method. IQ scores, stress and rest MBF, and CFR were compared between the methods, using Chi-square and Kruskal-Wallis tests. Results: In the visual analysis, IQ was significantly higher by 10 mm Gaussian filtering, compared to other sizes of filter (PP=0.923 and 0.855 for readers 1 and 2, respectively. SNR was significantly higher in 10 mm Gaussian filter. There was a significant difference in stress and rest MBF between several vascular territories. However CFR was not significantly different according to various filtering methods. Conclusion: Post-reconstruction Gaussian filtering with a filter size of 10 mm significantly enhances the IQ of N-13 ammonia PET-CT, without changing the results of CFR calculation. .

Effect of Post-Reconstruction Gaussian Filtering on Image Quality and Myocardial Blood Flow Measurement with N-13 Ammonia PET

International Nuclear Information System (INIS)

Kim, Hyeon Sik; Cho, Sang-Geon; Kim, Ju Han; Kwon, Seong Young; Lee, Byeong-il; Bom, Hee-Seung

2014-01-01

In order to evaluate the effect of post-reconstruction Gaussian filtering on image quality and myocardial blood flow (MBF) measurement by dynamic N-13 ammonia positron emission tomography (PET), we compared various reconstruction and filtering methods with image characteristics. Dynamic PET images of three patients with coronary artery disease (male-female ratio of 2:1; age: 57, 53, and 76 years) were reconstructed, using filtered back projection (FBP) and ordered subset expectation maximization (OSEM) methods. OSEM reconstruction consisted of OSEM-2I, OSEM-4I, and OSEM-6I with 2, 4, and 6 iterations, respectively. The images, reconstructed and filtered by Gaussian filters of 5, 10, and 15 mm, were obtained, as well as non-filtered images. Visual analysis of image quality (IQ) was performed using a 3-grade scoring system by 2 independent readers, blinded to the reconstruction and filtering methods of stress images. Then, signal-to-noise ratio (SNR) was calculated by noise and contrast recovery (CR). Stress and rest MBF and coronary flow reserve (CFR) were obtained for each method. IQ scores, stress and rest MBF, and CFR were compared between the methods, using Chi-square and Kruskal-Wallis tests. In the visual analysis, IQ was significantly higher by 10 mm Gaussian filtering, compared to other sizes of filter (P<0.001 for both readers). However, no significant difference of IQ was found between FBP and various numbers of iteration in OSEM (P=0.923 and 0.855 for readers 1 and 2, respectively). SNR was significantly higher in 10 mm Gaussian filter. There was a significant difference in stress and rest MBF between several vascular territories. However CFR was not significantly different according to various filtering methods. Post-reconstruction Gaussian filtering with a filter size of 10 mm significantly enhances the IQ of N-13 ammonia PET-CT, without changing the results of CFR calculation

Intermediate heat exchanger tube vibration induced by cross and parallel mixed flow

International Nuclear Information System (INIS)

Kawamura, Koji

1986-01-01

The characteristics of pool type LMFBR intermediate heat exchanger (IHX) tube vibrations induced by cross and parallel mixed flow were basically investigated. Secondary coolant in IHX tube bundle is mixed flow of parallel jit flow along the tube axis through flow holes in baffle plates and cross flow. By changing these two flow rate, flow distributions vary in the tube bundle. Mixed flow also induces vibrations which cause fretting wear and fatigue of tube. It is therefore very important to evaluate the tube vibration characteristics for estimating the tube integrity. The results show that the relationships between tube vibrations and flow distributions in the tube bundle were cleared, and mixed flow induced tube vibration could be evaluated on the base of the characteristics of both parallel and cross flow induced vibration. From these investigations it could be concluded that the characteristics of tube vibration for various flow distributions can be systematically evaluated. (author)

Influence of hole imperfection on jet cross flow interaction

International Nuclear Information System (INIS)

Jovanovic, M.B.; Lange, H.C. de; Steenhoven, A.A. van

2006-01-01

The influence of a small hole geometry variation on the jet cross flow interaction is investigated experimentally using particle image velocimetry and liquid crystal thermography. The flow characteristics correspond to film cooling in gas turbines. A production imperfection is represented with the small variation of the hole geometry. The experiments were conducted without and with the hole imperfection at three velocity ratios. If the imperfection is absent, the flow field is stable and clockwise vortices are detected downstream. The imperfection blocks the hole, accelerates the jet and changes the formation of large vortical structures. It produces the additional windward vortices, which influence the flow field and enhance the inflow of the cross-stream towards the cooled surface. The imperfection reduces the film cooling effectiveness

Cross-Dependency Inference in Multi-Layered Networks: A Collaborative Filtering Perspective.

Science.gov (United States)

Chen, Chen; Tong, Hanghang; Xie, Lei; Ying, Lei; He, Qing

2017-08-01

The increasingly connected world has catalyzed the fusion of networks from different domains, which facilitates the emergence of a new network model-multi-layered networks. Examples of such kind of network systems include critical infrastructure networks, biological systems, organization-level collaborations, cross-platform e-commerce, and so forth. One crucial structure that distances multi-layered network from other network models is its cross-layer dependency, which describes the associations between the nodes from different layers. Needless to say, the cross-layer dependency in the network plays an essential role in many data mining applications like system robustness analysis and complex network control. However, it remains a daunting task to know the exact dependency relationships due to noise, limited accessibility, and so forth. In this article, we tackle the cross-layer dependency inference problem by modeling it as a collective collaborative filtering problem. Based on this idea, we propose an effective algorithm Fascinate that can reveal unobserved dependencies with linear complexity. Moreover, we derive Fascinate-ZERO, an online variant of Fascinate that can respond to a newly added node timely by checking its neighborhood dependencies. We perform extensive evaluations on real datasets to substantiate the superiority of our proposed approaches.

Laboratory-scale integrated ARP filter test

Energy Technology Data Exchange (ETDEWEB)

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

2016-03-01

The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). Recently, the low filter flux through the ARP of approximately 5 gallons per minute has limited the rate at which radioactive liquid waste can be treated. Salt Batch 6 had a lower processing rate and required frequent filter cleaning. There is a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. This task attempted to simulate the entire ARP process, including multiple batches (5), washing, chemical cleaning, and blending the feed with heels and recycle streams. The objective of the tests was to determine whether one of these processes is causing excessive fouling of the crossflow or secondary filter. The authors conducted the tests with feed solutions containing 6.6 M sodium Salt Batch 6 simulant supernate with no MST.

A filtering technique for solving the advection equation in two-phase flow problems

International Nuclear Information System (INIS)

Devals, C.; Heniche, M.; Bertrand, F.; Tanguy, P.A.; Hayes, R.E.

2004-01-01

The aim of this work is to develop a numerical strategy for the simulation of two-phase flow in the context of chemical engineering applications. The finite element method has been chosen because of its flexibility to deal with complex geometries. One of the key points of two-phase flow simulation is to determine precisely the position of the interface between the two phases, which is an unknown of the problem. In this case, the interface can be tracked by the advection of the so-called color function. It is well known that the solution of the advection equation by most numerical schemes, including the Streamline Upwind Petrov-Galerkin (SUPG) method, may exhibit spurious oscillations. This work proposes an approach to filter out these oscillations by means of a change of variable that is efficient for both steady state and transient cases. First, the filtering technique will be presented in detail. Then, it will be applied to two-dimensional benchmark problems, namely, the advection skew to the mesh and the Zalesak's problems. (author)

Development of Test Protocols for International Space Station Particulate Filters

Science.gov (United States)

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

2015-01-01

Air quality control on the International Space Station (ISS) is a vital requirement for maintaining a clean environment for the crew and the hardware. This becomes a serious challenge in pressurized space compartments since no outside air ventilation is possible, and a larger particulate load is imposed on the filtration system due to lack of gravitational settling. The ISS Environmental Control and Life Support System (ECLSS) uses a filtration system that has been in use for over 14 years and has proven to meet this challenge. The heart of this system is a traditional High-Efficiency Particulate Air (HEPA) filter configured to interface with the rest of the life support elements and provide effective cabin filtration. The filter element for this system has a non-standard cross-section with a length-to-width ratio (LW) of 6.6. A filter test setup was designed and built to meet industry testing standards. A CFD analysis was performed to initially determine the optimal duct geometry and flow configuration. Both a screen and flow straighter were added to the test duct design to improve flow uniformity and face velocity profiles were subsequently measured to confirm. Flow quality and aerosol mixing assessments show that the duct flow is satisfactory for the intended leak testing. Preliminary leak testing was performed on two different ISS filters, one with known perforations and one with limited use, and results confirmed that the testing methods and photometer instrument are sensitive enough to detect and locate compromised sections of an ISS BFE.Given the engineering constraints in designing spacecraft life support systems, it is anticipated that non-industry standard filters will be required in future designs. This work is focused on developing test protocols for testing the ISS BFE filters, but the methodology is general enough to be extended to other present and future spacecraft filters. These techniques for characterizing the test duct and perform leak testing

Treatment of two-phase turbulent mixing, void drift and diversion cross-flow in a hydraulically non-equilibrium subchannel flow

International Nuclear Information System (INIS)

Sadatomi, Michio; Kawahara, Akimaro; Sato, Yoshifusa

1997-01-01

A practical way of treating two-phase turbulent mixing, void drift and diversion cross-flow on a subchannel analysis has been studied. Experimental data on the axial variations of subchannel flow parameters, such as flow rates of both phases, pressure, void fraction and concentrations of tracers for both phases, were obtained for hydraulically non-equilibrium two-phase subchannel flows in a vertical multiple channel made up of two-identical circular subchannels. These data were analyzed on the basis of the following four assumptions: (1) the turbulent mixing is independent of both the void drift and the diversion cross-flow; (2) the turbulent mixing rates of both phases in a non-equilibrium flow are equal to those in the equilibrium flow that the flow under consideration will attain; (3) the void drift is independent of the diversion cross-flow; and (4) the lateral gas velocity due to the void drift is predictable from Lahey et al.'s void settling model even in a non-equilibrium flow with the diversion cross-flow. The validity of the assumptions (1) and (2) was assured by comparing the concentration distribution data with the calculations, and that of the assumptions (3) and (4) by analyzing the data on flow rates of both phases, pressure and void fraction (author)

Analysis of the cross flow in a radial inflow turbine scroll

Science.gov (United States)

Hamed, A.; Abdallah, S.; Tabakoff, W.

1977-01-01

Equations of motion were derived, and a computational procedure is presented, for determining the nonviscous flow characteristics in the cross-sectional planes of a curved channel due to continuous mass discharge or mass addition. An analysis was applied to the radial inflow turbine scroll to study the effects of scroll geometry and the through flow velocity profile on the flow behavior. The computed flow velocity component in the scroll cross-sectional plane, together with the through flow velocity profile which can be determined in a separate analysis, provide a complete description of the three dimensional flow in the scroll.

Multilevel Bloom Filters for P2P Flows Identification Based on Cluster Analysis in Wireless Mesh Network

Directory of Open Access Journals (Sweden)

Xia-an Bi

2015-01-01

Full Text Available With the development of wireless mesh networks and distributed computing, lots of new P2P services have been deployed and enrich the Internet contents and applications. The rapid growth of P2P flows brings great pressure to the regular network operation. So the effective flow identification and management of P2P applications become increasingly urgent. In this paper, we build a multilevel bloom filters data structure to identify the P2P flows through researches on the locality characteristics of P2P flows. Different level structure stores different numbers of P2P flow rules. According to the characteristics values of the P2P flows, we adjust the parameters of the data structure of bloom filters. The searching steps of the scheme traverse from the first level to the last level. Compared with the traditional algorithms, our method solves the drawbacks of previous schemes. The simulation results demonstrate that our algorithm effectively enhances the performance of P2P flows identification. Then we deploy our flow identification algorithm in the traffic monitoring sensors which belong to the network traffic monitoring system at the export link in the campus network. In the real environment, the experiment results demonstrate that our algorithm has a fast speed and high accuracy to identify the P2P flows; therefore, it is suitable for actual deployment.

Removal of silver from wastewater using cross flow microfiltration

Directory of Open Access Journals (Sweden)

Zanain M.

2013-04-01

Full Text Available Removal of silver from wastewater was investigated using continuous cross flow microfiltration (MF technique hollow fiber membranes with a pore size 0.2μm, with sorbent coated material Al2O3/SDSH2Dz particle size (8 μm. The coating investigated was dithizone (Diphenylthiocarbazone in 0.005M ammonia solution. In the filtration of silver ion solutions, the effects of the permeate flow rate and cross flow velocity on the absorption of silver ion solutions, and since the pore size of membrane (=0.2 μm is smaller then that of the (Al2O3, no need to consider the variation of (Al2O3.rejection as it can be considered to be 100%. The amount of silver absorbed into sorbent material Al2O3/SDSH2Dz was (25.35, 39.68 ppm for the cross flown velocity of 5, 2.5 L/hr respectively, and were the results as function of permeate flow was (25.35, 39.68 ppm for the velocity of 5, 2.5 L/hr respectively.

27 CFR 19.328 - Wash water.

Science.gov (United States)

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Wash water. 19.328 Section... THE TREASURY LIQUORS DISTILLED SPIRITS PLANTS Production Chemical By-Products § 19.328 Wash water. Water used in washing chemicals to remove spirits therefrom may be run into a wash tank or a distilling...

Cross-border flow of health information

DEFF Research Database (Denmark)

Di Iorio, Concetta Tania; Carinci, Fabrizio; Brillante, Massimo

2013-01-01

The EUBIROD project aims to perform a cross-border flow of diabetes information across 19 European countries using the BIRO information system, which embeds privacy principles and data protection mechanisms in its architecture (privacy by design). A specific task of EUBIROD was to investigate...

THE EFFECT OF THE REYNOLDS NUMBER OF AIR FLOW TO THE PARTICLE COLLECTION EFFICIENCY OF A FIBROUS FILTER MEDIUM WITH CYLINDRICAL SECTION

Directory of Open Access Journals (Sweden)

George P. Kouropoulos

2014-01-01

Full Text Available At this study an attempt for the theoretical approach of the Re ynolds number effect of air flow to the particle collection efficiency of a fibrous fil ter with cylindrical section will be made. Initially, a report of the air filtration models to fibrous filter media will be presented along with an explanation of both the parameters and the physical quantities which govern the air filtration process. Furthermore, the resul ting equation from the mathematical model will be applied to a real filter medium and the characteristic curves of filter efficiency will be drawn. The change of a filter medi um efficiency with regard to the Reynolds number of air flow that passes through the filt er, derived from the curves, will be studied. The general conclusion that we have is that as the Reynolds number of filtered air increases, the collection efficiency of the filter decreases.

Study on an Undershot Cross-Flow Water Turbine with Straight Blades

Directory of Open Access Journals (Sweden)

Yasuyuki Nishi

2015-01-01

Full Text Available Small-scale hydroelectric power generation has recently attracted considerable attention. The authors previously proposed an undershot cross-flow water turbine with a very low head suitable for application to open channels. The water turbine was of a cross-flow type and could be used in open channels with the undershot method, remarkably simplifying its design by eliminating guide vanes and the casing. The water turbine was fitted with curved blades (such as the runners of a typical cross-flow water turbine installed in tube channels. However, there was ambiguity as to how the blades’ shape influenced the turbine’s performance and flow field. To resolve this issue, the present study applies straight blades to an undershot cross-flow water turbine and examines the performance and flow field via experiments and numerical analyses. Results reveal that the output power and the turbine efficiency of the Straight Blades runner were greater than those of the Curved Blades runner regardless of the rotational speed. Compared with the Curved Blades runner, the output power and the turbine efficiency of the Straight Blades runner were improved by about 31.7% and about 67.1%, respectively.

The Use of Nonlinear Constitutive Equations to Evaluate Draw Resistance and Filter Ventilation

Directory of Open Access Journals (Sweden)

Eitzinger B

2014-12-01

Full Text Available This study investigates by nonlinear constitutive equations the influence of tipping paper, cigarette paper, filter, and tobacco rod on the degree of filter ventilation and draw resistance. Starting from the laws of conservation, the path to the theory of fluid dynamics in porous media and Darcy's law is reviewed and, as an extension to Darcy's law, two different nonlinear pressure drop-flow relations are proposed. It is proven that these relations are valid constitutive equations and the partial differential equations for the stationary flow in an unlit cigarette covering anisotropic, inhomogeneous and nonlinear behaviour are derived. From these equations a system of ordinary differential equations for the one-dimensional flow in the cigarette is derived by averaging pressure and velocity over the cross section of the cigarette. By further integration, the concept of an electrical analog is reached and discussed in the light of nonlinear pressure drop-flow relations. By numerical calculations based on the system of ordinary differential equations, it is shown that the influence of nonlinearities cannot be neglected because variations in the degree of filter ventilation can reach up to 20% of its nominal value.

LES of turbulent jet in cross-flow: Part 1 – A numerical validation study

DEFF Research Database (Denmark)

Cavar, Dalibor; Meyer, Knud Erik

2012-01-01

The paper presents results of a LES based numerical simulation of the turbulent jet-in-cross-flow (JICF) flowfield, with Reynolds number based on cross-flow velocity and jet diameter Re=2400 and jet-to-cross-flow velocity ratio of R=3.3. The JICF flow case has been investigated in great detail...

Cross-section of single-crystal materials used as thermal neutron filters

International Nuclear Information System (INIS)

Adib, M.

2005-01-01

Transmission properties of several single crystal materials important for neutron scattering instrumentation are presented. A computer codes are developed which permit the calculation of thermal diffuse and Bragg-scattering cross-sections of silicon., and sapphire as a function of material's constants, temperature and neutron energy, E, in the range 0.1 MeV .A discussion of the use of their single-crystal as a thermal neutron filter in terms of the optimum crystal thickness, mosaic spread, temperature, cutting plane and tuning for efficient transmission of thermal-reactor neutrons is given

Discharge Coefficient Measurements for Flow Through Compound-Angle Conical Holes with Cross-Flow

Directory of Open Access Journals (Sweden)

M. E. Taslim

2004-01-01

Full Text Available Diffusion-shaped film holes with compound angles are currently being investigated for high temperature gas turbine airfoil film cooling. An accurate prediction of the coolant blowing rate through these film holes is essential in determining the film effectiveness. Therefore, the discharge coefficients associated with these film holes for a range of hole pressure ratios is essential in designing airfoil cooling circuits. Most of the available discharge coefficient data in open literature has been for cylindrical holes. The main objective of this experimental investigation was to measure the discharge coefficients for subsonic as well as supersonic pressure ratios through a single conical-diffusion hole. The conical hole has an exit-to-inlet area ratio of 4, a nominal flow length-to-inlet diameter ratio of 4, and an angle with respect to the exit plane (inclination angle of 0°, 30°, 45°, and 60°. Measurements were performed with and without a cross-flow. For the cases with a cross-flow, discharge coefficients were measured for each of the hole geometries and 5 angles between the projected conical hole axis and the cross-flow direction of 0°, 45°, 90°, 135°, and 180°. Results are compared with available data in open literature for cylindrical film holes as well as limited data for conical film holes.

Dual states estimation of a subsurface flow-transport coupled model using ensemble Kalman filtering

KAUST Repository

El Gharamti, Mohamad

2013-10-01

Modeling the spread of subsurface contaminants requires coupling a groundwater flow model with a contaminant transport model. Such coupling may provide accurate estimates of future subsurface hydrologic states if essential flow and contaminant data are assimilated in the model. Assuming perfect flow, an ensemble Kalman filter (EnKF) can be used for direct data assimilation into the transport model. This is, however, a crude assumption as flow models can be subject to many sources of uncertainty. If the flow is not accurately simulated, contaminant predictions will likely be inaccurate even after successive Kalman updates of the contaminant model with the data. The problem is better handled when both flow and contaminant states are concurrently estimated using the traditional joint state augmentation approach. In this paper, we introduce a dual estimation strategy for data assimilation into a one-way coupled system by treating the flow and the contaminant models separately while intertwining a pair of distinct EnKFs, one for each model. The presented strategy only deals with the estimation of state variables but it can also be used for state and parameter estimation problems. This EnKF-based dual state-state estimation procedure presents a number of novel features: (i) it allows for simultaneous estimation of both flow and contaminant states in parallel; (ii) it provides a time consistent sequential updating scheme between the two models (first flow, then transport); (iii) it simplifies the implementation of the filtering system; and (iv) it yields more stable and accurate solutions than does the standard joint approach. We conducted synthetic numerical experiments based on various time stepping and observation strategies to evaluate the dual EnKF approach and compare its performance with the joint state augmentation approach. Experimental results show that on average, the dual strategy could reduce the estimation error of the coupled states by 15% compared with the

Hair dyeing, hair washing and hair cortisol concentrations among women from the healthy start study

DEFF Research Database (Denmark)

Kristensen, Sheila K.; Larsen, Sofus C.; Olsen, Nanna J.

2017-01-01

Background: Hair cortisol concentration (HCC) has been suggested as a promising marker for chronic stress. However, studies investigating the influence of hair dyeing and hair washing frequency on HCC have shown inconsistent results. Objective: To examine associations between HCC and hair dyeing...... status or weekly hair washing frequency among women. Methods: This cross-sectional study was based on data from 266 mothers participating in the Healthy Start intervention study. HCC was measured in the proximal end of the hair (1–2 cm closest to the scalp) while hair dyeing status, frequency of hair...... washing and covariates were reported by the women. Linear regression analyses were applied to assess the associations between HCC and hair dyeing or weekly frequency of hair washing. Results: No statistically significant difference (p = 0.91) in HCC was found between women who dyed hair (adjusted mean...

Pre-study of exhaust gases of diesel engines with 'open' and 'wall-flow' diesel particulate filters and their toxicity

International Nuclear Information System (INIS)

Verbeek, R.; Rabe, E.

2007-04-01

The Dutch Ministry of VROM (Housing, Spatial Planning and the Environment) has recently introduced financial support programmes for the installation of Diesel Particulate Filters on both passenger cars and trucks. To obtain funding, the minimum filtration efficiency for passenger cars should be 30%. For trucks there are 2 categories: minimally 50% and minimally 90%. The 30 to 50% filtration efficiency is in practice realized with so called 'open' filters. More than 90% filtration efficiency is accomplished with the 'wall-flow' or 'closed' diesel particulate filter. All filters are combined with an integrated oxidation catalyst. The oxidation catalyst is necessary for the regeneration of the particulate matter captured within the filter; it will also oxidize and hence reduce components like unburned hydrocarbons and carbon monoxide. For any automotive catalytic after-treatment system there is theoretically a risk of undesirable reactions that might occur under certain conditions. Therefore, a number of international studies were conducted during the last decade to investigate the emission of potentially toxic components from diesel engines equipped with wall-flow diesel particulate filters and with oxidation catalysts. The results of these studies were generally positive: a reduction of many potentially toxic components and particulate mass although in some cases certain potentially toxic components had increased. The open filters have a very similar oxidation catalyst but a different way of filter trapping. The question was raised whether there would be significant risks of formation of certain potentially toxic components or ultra-fine particles that might be harmful for human health. VROM asked TNO to conduct this pre-study, which was also meant as a preparation for an experimental study. Several international studies as well as studies conducted by TNO during the past 8 years were evaluated with the focus on information on known toxic components, on particle

An improved collaborative filtering approach for predicting cross-category purchases based on binary market basket data

OpenAIRE

Mild, Andreas; Reutterer, Thomas

2002-01-01

Retail managers have been interested in learning about cross-category purchase behavior of their customers for a fairly long time. More recently, the task of inferring cross-category relationship patterns among retail assortments is gaining attraction due to its promotional potential within recommender systems used in online environments. Collaborative filtering algorithms are frequently used in such settings for the prediction of choices, preferences and/or ratings of online users. This pape...

Intracycle angular velocity control of cross-flow turbines

Science.gov (United States)

Strom, Benjamin; Brunton, Steven L.; Polagye, Brian

2017-08-01

Cross-flow turbines, also known as vertical-axis turbines, are attractive for power generation from wind and water currents. Some cross-flow turbine designs optimize unsteady fluid forces and maximize power output by controlling blade kinematics within one rotation. One established method is to dynamically pitch the blades. Here we introduce a mechanically simpler alternative: optimize the turbine rotation rate as a function of angular blade position. We demonstrate experimentally that this approach results in a 59% increase in power output over standard control methods. Analysis of fluid forcing and blade kinematics suggest that power increase is achieved through modification of the local flow conditions and alignment of fluid force and rotation rate extrema. The result is a low-speed, structurally robust turbine that achieves high efficiency and could enable a new generation of environmentally benign turbines for renewable power generation.

Integration of Computer Tomography and Simulation Analysis in Evaluation of Quality of Ceramic-Carbon Bonded Foam Filter

Directory of Open Access Journals (Sweden)

Karwiński A.

2013-12-01

Full Text Available Filtration of liquid casting alloys is used in casting technologies for long time. The large quantity of available casting filters allows using them depending on casting technology, dimensions of casting and used alloys. Technological progress of material science allows of using new materials in production of ceramic filters. In this article the Computed Tomography (CT technique was use in order to evaluate the thickness of branch in cross section of 20ppi ceramic-carbon bonded foam filter. Than the 3D image of foam filter was used in computer simulation of flow of liquid metal thru the running system.

Cross-shore flow on the inner-shelf off southwest Portugal

Science.gov (United States)

Lamas, L.; Peliz, A.; Oliveira, P.; Dias, J.

2012-04-01

Velocity measurements from 4 bottom-mounted ADCP deployments (summers of 2006, 2007, 2008 and 2011) at a 12-m depth site off Sines, Portugal, complemented with time series of winds, waves and tides, are used to study the inner-shelf cross-shore flow dependence on wave, tidal and wind forcings. During these four summers, the dominating winds are from the north (upwelling-favorable), with strong diurnal sea breeze cycle throughout these periods. This quasi-steady wind circulation is sometimes interrupted by short event-like reversals. The observed records were split in different subsets according to tidal amplitude, wave height, cross- and along-shore wind magnitudes, and the vertical structure of the cross-shore flow was studied for each of these subsets. Despite different forcing conditions, the cross-shore velocity profiles usually show a vertical parabolic structure with maximum onshore flow at mid-depth, resembling the upwelling return flow for mid-shelf conditions, but atypical for the inner-shelf and in disagreement with other inner-shelf studies from other sites. We compare the observations with simplified 2D inner-shelf models and with results from other studies.

Washing scaling of GeneChip microarray expression

Directory of Open Access Journals (Sweden)

Krohn Knut

2010-05-01

Full Text Available Abstract Background Post-hybridization washing is an essential part of microarray experiments. Both the quality of the experimental washing protocol and adequate consideration of washing in intensity calibration ultimately affect the quality of the expression estimates extracted from the microarray intensities. Results We conducted experiments on GeneChip microarrays with altered protocols for washing, scanning and staining to study the probe-level intensity changes as a function of the number of washing cycles. For calibration and analysis of the intensity data we make use of the 'hook' method which allows intensity contributions due to non-specific and specific hybridization of perfect match (PM and mismatch (MM probes to be disentangled in a sequence specific manner. On average, washing according to the standard protocol removes about 90% of the non-specific background and about 30-50% and less than 10% of the specific targets from the MM and PM, respectively. Analysis of the washing kinetics shows that the signal-to-noise ratio doubles roughly every ten stringent washing cycles. Washing can be characterized by time-dependent rate constants which reflect the heterogeneous character of target binding to microarray probes. We propose an empirical washing function which estimates the survival of probe bound targets. It depends on the intensity contribution due to specific and non-specific hybridization per probe which can be estimated for each probe using existing methods. The washing function allows probe intensities to be calibrated for the effect of washing. On a relative scale, proper calibration for washing markedly increases expression measures, especially in the limit of small and large values. Conclusions Washing is among the factors which potentially distort expression measures. The proposed first-order correction method allows direct implementation in existing calibration algorithms for microarray data. We provide an experimental

Electrical resistance imaging of a time-varying interface in stratified flows using an unscented Kalman filter

International Nuclear Information System (INIS)

Ijaz, Umer Zeeshan; Khambampati, Anil Kumar; Kim, Kyung Youn; Chung, Soon Il; Kim, Sin

2008-01-01

In this paper, we estimate a time-varying interfacial boundary in stratified flows of two immiscible liquids using electrical resistance tomography. The interfacial boundary is approximated with front points spaced discretely along the interface. The design variables to be estimated are the locations of the front points, which are varying with the moving interface. The inverse problem is treated as a stochastic nonlinear state estimation problem with the nonstationary phase boundary (state) being estimated with the aid of an unscented Kalman filter. Numerical experiments are performed to evaluate the performance of an unscented Kalman filter. Specifically, a detailed analysis has been done on the effect of the number of front points and contrast ratio on the reconstruction performance. The reconstruction results show that an unscented Kalman filter is better suited for estimation in comparison to the conventional extended Kalman filter

The effect of bathymetric filtering on nearshore process model results

Science.gov (United States)

Plant, N.G.; Edwards, K.L.; Kaihatu, J.M.; Veeramony, J.; Hsu, L.; Holland, K.T.

2009-01-01

Nearshore wave and flow model results are shown to exhibit a strong sensitivity to the resolution of the input bathymetry. In this analysis, bathymetric resolution was varied by applying smoothing filters to high-resolution survey data to produce a number of bathymetric grid surfaces. We demonstrate that the sensitivity of model-predicted wave height and flow to variations in bathymetric resolution had different characteristics. Wave height predictions were most sensitive to resolution of cross-shore variability associated with the structure of nearshore sandbars. Flow predictions were most sensitive to the resolution of intermediate scale alongshore variability associated with the prominent sandbar rhythmicity. Flow sensitivity increased in cases where a sandbar was closer to shore and shallower. Perhaps the most surprising implication of these results is that the interpolation and smoothing of bathymetric data could be optimized differently for the wave and flow models. We show that errors between observed and modeled flow and wave heights are well predicted by comparing model simulation results using progressively filtered bathymetry to results from the highest resolution simulation. The damage done by over smoothing or inadequate sampling can therefore be estimated using model simulations. We conclude that the ability to quantify prediction errors will be useful for supporting future data assimilation efforts that require this information.

Remediation of cadmium-contaminated paddy soils by washing with calcium chloride: Verification of on-site washing

International Nuclear Information System (INIS)

Makino, Tomoyuki; Kamiya, Takashi; Takano, Hiroyuki; Itou, Tadashi; Sekiya, Naoki; Sasaki, Kouta; Maejima, Yuji; Sugahara, Kazuo

2007-01-01

We developed a new, three-step soil-wash method to remediate Cd-contaminated paddy fields. The method comprises (1) chemically washing the field soil with a CaCl 2 solution; (2) washing the treated soil with water to eliminate residual Cd and CaCl 2 ; and (3) on-site treatment of wastewater using a portable wastewater treatment system. Cd concentrations in the treated water were below Japan's environmental quality standard (0.01 mg Cd L -1 ), and the removal of Cd from the exchangeable fraction was 55% and from the acid-soluble fraction 15%. While soil fertility properties were affected by the soil washing, adverse effects were not crucial and could be corrected. The washing had no affect on rice growth, and reduced the average Cd concentration in rice grains by about two-thirds compared to a control plot. These results confirmed the effectiveness of the soil-wash method in remediating Cd-contaminated paddy fields. - In situ soil washing in a paddy field using an on-site wastewater treatment system resulted in an effective decrease of Cd in soil and rice grains without affecting rice yield

From Microwave Filter to Digital Filter and Back Again

DEFF Research Database (Denmark)

Dalby, Arne Brejning

1989-01-01

A new very simple state variable flow graph representation for interdigital transmission line bandpass filters is presented, which has led to two important results: 1) A new type of digital filter with properties, that surpass the properties of most other (all pole) digital filtertypes. 2) The st...

Aquatic Plant/microbial Filters for Treating Septic Tank Effluent

Science.gov (United States)

Wolverton, B. C.

1988-01-01

The use of natural biological processes for treating many types of wastewater have been developed by NASA at the John C. Stennis Space Center, NSTL, Mississippi, during the past 15 years. The simplest form of this technology involves the use of aquatic plant/marsh filters for treatment of septic tank effluent. Septic tank effluent from single home units can be treated to advanced secondary levels and beyond by using a 37.2 sq m (400 sq ft) surface area washed gravel filter. This filter is generally 0.3 m (1 ft) deep with a surface cover of approximately 0.15 m (6 in.) of gravel. The plants in this filter are usually aesthetic or ornamental such as calla lily (Zantedeschia aethiopica), canna lily (Canna flaccida), elephant ear (Colocasia esculenta), and water iris (Iris pseudacorus).

Wavelength interrogation of fiber Bragg grating sensors based on crossed optical Gaussian filters.

Science.gov (United States)

Cheng, Rui; Xia, Li; Zhou, Jiaao; Liu, Deming

2015-04-15

Conventional intensity-modulated measurements require to be operated in linear range of filter or interferometric response to ensure a linear detection. Here, we present a wavelength interrogation system for fiber Bragg grating sensors where the linear transition is achieved with crossed Gaussian transmissions. This unique filtering characteristic makes the responses of the two branch detections follow Gaussian functions with the same parameters except for a delay. The substraction of these two delayed Gaussian responses (in dB) ultimately leads to a linear behavior, which is exploited for the sensor wavelength determination. Beside its flexibility and inherently power insensitivity, the proposal also shows a potential of a much wider operational range. Interrogation of a strain-tuned grating was accomplished, with a wide sensitivity tuning range from 2.56 to 8.7 dB/nm achieved.

Corrosion and flow resistance of metal filter elements used in the cleanup of syngas from the Transport Gasifier at the Power Systems Development Facility

Energy Technology Data Exchange (ETDEWEB)

Robert S. Dahlin; E. Carl Landham; Xiaofeng Guan [Southern Research Institute, Wilsonville, AL (United States). Power Systems Development Facility

2008-07-01

At the Power Systems Development Facility (PSDF), a variety of filter elements and failsafes are being tested for the cleanup of coal-generated syngas from the Kellogg Brown and Root (KBR) Transport Gasifier. Thus far, no evidence of corrosion or plugging has been found in the HR-160 failsafes or sinterned metal fiber elements. However, a progressive corrosion and increase in pressure drop has been noted in the iron aluminide elements. The corrosion was first detected as reddish-brown spots of iron oxide after about 2,000 to 3,000 hours of syngas exposure. As the corrosion progressed, the spots of iron oxide merged to form a continuous scale after about 5,000 to 5,500 hours of exposure. With additional exposure, a black scale containing iron sulfide also appeared, and localized areas of sulfidation and plugging were noted in element cross sections. These effects have not resulted in any significant reduction in tensile strength, but a gradual increase in the clean element pressure drop has been noted. Flow test results suggest that there is an interaction between the corroded filter surface and the dustcake that effectively increases the residual cake flow resistance and baseline pressure drop. 10 refs., 14 figs., 1 tab.

Ice slurry flow and heat transfer during flow through tubes of rectangular and slit cross-sections

Directory of Open Access Journals (Sweden)

Niezgoda-Żelasko Beata

2014-09-01

Full Text Available The paper presents the results of experimental research of pressure drop and heat transfer coefficients of ice slurry during its flow through tubes of rectangular and slit cross-sections. Moreover, the work discusses the influence of solid particles, type of motion and cross-section on the changes in the pressure drop and heat transfer coefficient. The analysis presented in the paper allows for identification of the criterial relations used to calculate the Fanning factor and the Nusselt number for laminar and turbulent flow, taking into account elements such as phase change, which accompanies the heat transfer process. Ice slurry flow is treated as a generalized flow of a non-Newtonian fluid.

Enhanced post wash retention of combed DNA molecules by varying multiple combing parameters.

Science.gov (United States)

Yadav, Hemendra; Sharma, Pulkit

2017-11-01

Recent advances in genomics have created a need for efficient techniques for deciphering information hidden in various genomes. Single molecule analysis is one such technique to understand molecular processes at single molecule level. Fiber- FISH performed with the help of DNA combing can help us in understanding genetic rearrangements and changes in genome at single DNA molecule level. For performing Fiber-FISH we need high retention of combed DNA molecules post wash as Fiber-FISH requires profuse washing. We optimized combing process involving combing solution, method of DNA mounting on glass slides and coating of glass slides to enhance post-wash retention of DNA molecules. It was found that average number of DNA molecules observed post-wash per field of view was maximum with our optimized combing solution. APTES coated glass slides showed lesser retention than PEI surface but fluorescent intensity was higher in case of APTES coated surface. Capillary method used to mount DNA on glass slides also showed lesser retention but straight DNA molecules were observed as compared to force flow method. Copyright © 2017 Elsevier Inc. All rights reserved.

Replacement of fluid-filter elements without interruption of flow

Science.gov (United States)

Kotler, R. A.; Ward, J. B.

1969-01-01

Gatling-type filter assembly, preloaded with several filter elements enables filter replacement without breaking into the operative fluid system. When the filter element becomes contaminated, a unit inner subassembly is rotated 60 degrees to position a clean filter in the line.

Scalable design of an IMS cross-flow micro-generator/ion detector

International Nuclear Information System (INIS)

Ortiz, Juan J; Nigri, Christian; Lasorsa, Carlos; Ortiz, Guillermo P

2013-01-01

Ion-mobility spectrometry (IMS) is an analytical technique used to separate and identify ionized gas molecules based on their mobility in a carrier buffer gas. Such methods come in a large variety of versions that currently allow ion identification at and above the millimeter scale. Here, we present a design for a cross-flow IMS method able to generate and detect ions at the sub-millimeter scale. We propose a novel ion focusing strategy and test it in a prototype device using nitrogen as a sample gas, and also with simulations using four different sample gases. By introducing an original lobular ion generation localized to a few ten of microns and substantially simplifying the design, our device is able to keep constant laminar flow conditions for high flow rates. In this way, it avoids the turbulences in the gas flow, which would occur in other ion-focusing cross-flow methods limiting their performance at the sub-millimeter scale. Scalability of the proposed design can contribute to improve the resolving power and resolution of currently available cross-flow methods. (paper)

Dynamic Kalman filtering to separate low-frequency instabilities from turbulent fluctuations: Application to the Large-Eddy Simulation of unsteady turbulent flows

International Nuclear Information System (INIS)

Cahuzac, A; Boudet, J; Borgnat, P; Lévêque, E

2011-01-01

A dynamic method based on Kalman filtering is presented to isolate low-frequency unsteadiness from turbulent fluctuations in the large-eddy simulation (LES) of unsteady turbulent flows. The method can be viewed as an adaptive exponential smoothing, in which the smoothing factor adapts itself dynamically to the local behavior of the flow. Interestingly, the proposed method does not require any empirical tuning. In practice, it is used to estimate a shear-improved Smagorinsky viscosity, in which the low-frequency component of the velocity field is used to estimate a correction term to the Smagorinsky viscosity. The LES of the flow past a circular cylinder at Reynolds number Re D = 4.7 × 10 4 is examined as a challenging test case. Good comparisons are obtained with the experimental results, indicating the relevance of the shear-improved Smagorinsky model and the efficiency of the Kalman filtering. Finally, the adaptive cut-off of the Kalman filter is investigated, and shown to adapt locally and instantaneously to the complex flow around the cylinder.

Evidence of prehistoric flooding and the potential for future extreme flooding at Coyote Wash, Yucca Mountain, Nye County, Nevada

International Nuclear Information System (INIS)

Glancy, P.A.

1994-01-01

Coyote Wash, an approximately 0.3-square-mile drainage on the eastern flank of Yucca Mountain, is the potential location for an exploratory shaft to evaluate the suitability of Yucca Mountain for construction of an underground repository for the storage of high-level radioactive wastes. An ongoing investigation is addressing the potential for hazards to the site and surrounding areas from flooding and related fluvial-debris movement. Unconsolidated sediments in and adjacent to the channel of North Fork Coyote Wash were examined for evidence of past floods. Trenches excavated across and along the valley bottom exposed multiple flood deposits, including debris-flow deposits containing boulders as large as 2 to 3 feet in diameter. Most of the alluvial deposition probably occurred during the late Quaternary. Deposits at the base of the deepest trench overlie bedrock and underlie stream terraces adjacent to the channel; these sediments are moderately indurated and probably were deposited during the late Pleistocene. Overlying nonindurated deposits clearly are younger and may be of Holocene age. This evidence of intense flooding during the past indicates that severe flooding and debris movement are possible in the future. Empirical estimates of large floods of the past range from 900 to 2,600 cubic feet per second from the 0.094-square-mile drainage area of North Fork Coyote Wash drainage at two proposed shaft sites. Current knowledge indicates that mixtures of water and debris are likely to flow from North Fork Coyote Wash at rates up to 2,500 cubic feet per second. South Fork Coyote Wash, which has similar basin area and hydraulic characteristics, probably will have concurrent floods of similar magnitudes. The peak flow of the two tributaries probably would combine near the potential sites for the exploratory shaft to produce future flow of water and accompanying debris potentially as large as 5,000 cubic feet per second

Factors Affecting the Levels of Heavy Metals in Juices Processed with Filter Aids.

Science.gov (United States)

Wang, Zhengfang; Jackson, Lauren S; Jablonski, Joseph E

2017-06-01

This study investigated factors that may contribute to the presence of arsenic and other heavy metals in apple and grape juices processed with filter aids. Different types and grades of filter aids were analyzed for arsenic, lead, and cadmium with inductively coupled plasma-tandem mass spectrometry. Potential factors affecting the transfer of heavy metals to juices during filtration treatments were evaluated. Effects of washing treatments on removal of heavy metals from filter aids were also determined. Results showed that diatomaceous earth (DE) generally contained a higher level of arsenic than perlite, whereas perlite had a higher lead content than DE. Cellulose contained the lowest level of arsenic among the surveyed filter aids. All samples of food-grade filter aids contained arsenic and lead levels that were below the U.S. Pharmacopeia and National Formulary limits of 10 ppm of total leachable arsenic and lead for food-grade DE filter aids. Two samples of arsenic-rich (>3 ppm) food-grade filter aids raised the level of arsenic in apple and grape juices during laboratory-scale filtration treatments, whereas three samples of low-arsenic (filter aids did not affect arsenic levels in filtered juices. Filtration tests with simulated juices (pH 2.9 to 4.1, Brix [°Bx] 8.2 to 18.1, total suspended solids [TSS] 0.1 to 0.5%) showed that pH or sugar content had no effect on arsenic levels of filtered juices, whereas arsenic content of filtered juice was elevated when higher amounts of filter aid were used for filtration. Authentic unfiltered apple juice (pH 3.6, °Bx 12.9, TSS 0.4%) and grape juice (pH 3.3, °Bx 16.2, TSS 0.05%) were used to verify results obtained with simulated juices. However, body feed ratio did not affect the arsenic content of filtered authentic juices. Washing treatments were effective at reducing arsenic, but not cadmium or lead, concentrations in a DE filter aid. This study identified ways to reduce the amount of arsenic transferred to juices

Remediation of cadmium contamination in paddy soils by washing with chemicals: Selection of washing chemicals

International Nuclear Information System (INIS)

Makino, Tomoyuki; Sugahara, Kazuo; Sakurai, Yasuhiro; Takano, Hiroyuki; Kamiya, Takashi; Sasaki, Kouta; Itou, Tadashi; Sekiya, Naoki

2006-01-01

The efficiencies of neutral salts, strong acids, and chelates were tested for extracting cadmium (Cd) from three paddy soils. The higher the selectivity of the cations of the added neutral salts toward soil adsorption sites, the lower the pH in the extracts and the more soil Cd could be extracted. In addition, soil carbon and nitrogen contents and mineral composition were closely associated with the amount of Cd extracted. Calcium chloride and iron(III) chloride were selected as wash chemicals to restore Cd-contaminated paddy soils in situ. Washing with calcium chloride led to the formation of Cd chloride complexes, enhancing Cd extraction from the soils. The washing also substantially decreased soil levels of exchangeable and acid-soluble Cd, which are the major forms of bioavailable Cd for rice (Oryza sativa L.). The optimum conditions for in situ soil washing were also determined for calcium chloride. - Calcium chloride and iron(III) chloride were useful for the in situ washing of Cd-contaminated paddy soils

Two-Phase Gas-Liquid Flow Structure Characteristics under Periodic Cross Forces Action

Directory of Open Access Journals (Sweden)

V. V. Perevezentsev

2015-01-01

Full Text Available The article presents a study of two-phase gas-liquid flow under the action of periodic cross forces. The work objective is to obtain experimental data for further analysis and have structure characteristics of the two-phase flow movement. For research, to obtain data without disturbing effect on the flow were used optic PIV (Particle Image Visualization methods because of their noninvasiveness. The cross forces influence was provided by an experimental stand design to change the angular amplitudes and the periods of channel movement cycle with two-phase flow. In the range of volume gas rates was shown a water flow rate versus the inclination angle of immovable riser section and the characteristic angular amplitudes and periods of riser section inclination cycle under periodic cross forces. Data on distribution of average water velocity in twophase flow in abovementioned cases were also obtained. These data allowed us to draw a conclusion that a velocity distribution depends on the angular amplitude and on the period of the riser section roll cycle. This article belongs to publications, which study two-phase flows with no disturbing effect on them. Obtained data give an insight into understanding a pattern of twophase gas-liquid flow under the action of periodic cross forces and can be used to verify the mathematical models of the CFD thermo-hydraulic codes. In the future, the work development expects taking measurements with more frequent interval in the ranges of angular amplitudes and periods of the channel movement cycle and create a mathematical model to show the action of periodic cross forces on two-phase gas-liquid flow.

Radiotracer study of wash load movement in a drum-type fabric washing machine using a gamma camera

Energy Technology Data Exchange (ETDEWEB)

Balt, A.P.; Brekel, L.D.M. van den; Vandecasteele, C.; Kolar, Z.

1987-01-01

A study was made of the movement of the wash loads in a drum-type washing machine. For this purpose a sup(99m)Tc source was attached to one or two separate textile pieces and the subsequent source positions were determined by means of a gamma-camera. The wash load movement pattern appears to depend on the type of textile material and its amount, as well as on the volume of water present in the washing machine.

Radiotracer study of wash load movement in a drum-type fabric washing machine using a gamma camera

International Nuclear Information System (INIS)

Balt, A.P.; Brekel, L.D.M. van den; Vandecasteele, C.; Kolar, Z.

1987-01-01

A study was made of the movement of the wash loads in a drum-type washing machine. For this purpose a sup(99m)Tc source was attached to one or two separate textile pieces and the subsequent source positions were determined by means of a gamma-camera. The wash load movement pattern appears to depend on the type of textile material and its amount, as well as on the volume of water present in the washing machine. (author)

A post-implementation evaluation of ceramic water filters distributed to tsunami-affected communities in Sri Lanka.

Science.gov (United States)

Casanova, Lisa M; Walters, Adam; Naghawatte, Ajith; Sobsey, Mark D

2012-06-01

Sri Lanka was devastated by the 2004 Indian Ocean tsunami. During recovery, the Red Cross distributed approximately 12,000 free ceramic water filters. This cross-sectional study was an independent post-implementation assessment of 452 households that received filters, to determine the proportion still using filters, household characteristics associated with use, and quality of household drinking water. The proportion of continued users was high (76%). The most common household water sources were taps or shallow wells. The majority (82%) of users used filtered water for drinking only. Mean filter flow rate was 1.12 L/hr (0.80 L/hr for households with taps and 0.71 for those with wells). Water quality varied by source; households using tap water had source water of high microbial quality. Filters improved water quality, reducing Escherichia coli for households (largely well users) with high levels in their source water. Households were satisfied with filters and are potentially long-term users. To promote sustained use, recovery filter distribution efforts should try to identify households at greatest long-term risk, particularly those who have not moved to safer water sources during recovery. They should be joined with long-term commitment to building supply chains and local production capacity to ensure safe water access.

Flow in curved ducts of varying cross-section

Science.gov (United States)

Sotiropoulos, F.; Patel, V. C.

1992-07-01

Two numerical methods for solving the incompressible Navier-Stokes equations are compared with each other by applying them to calculate laminar and turbulent flows through curved ducts of regular cross-section. Detailed comparisons, between the computed solutions and experimental data, are carried out in order to validate the two methods and to identify their relative merits and disadvantages. Based on the conclusions of this comparative study a numerical method is developed for simulating viscous flows through curved ducts of varying cross-sections. The proposed method is capable of simulating the near-wall turbulence using fine computational meshes across the sublayer in conjunction with a two-layer k-epsilon model. Numerical solutions are obtained for: (1) a straight transition duct geometry, and (2) a hydroturbine draft-tube configuration at model scale Reynolds number for various inlet swirl intensities. The report also provides a detailed literature survey that summarizes all the experimental and computational work in the area of duct flows.

Kalman/Map Filtering-Aided Fast Normalized Cross Correlation-Based Wi-Fi Fingerprinting Location Sensing

Directory of Open Access Journals (Sweden)

Yongliang Sun

2013-11-01

Full Text Available A Kalman/map filtering (KMF-aided fast normalized cross correlation (FNCC-based Wi-Fi fingerprinting location sensing system is proposed in this paper. Compared with conventional neighbor selection algorithms that calculate localization results with received signal strength (RSS mean samples, the proposed FNCC algorithm makes use of all the on-line RSS samples and reference point RSS variations to achieve higher fingerprinting accuracy. The FNCC computes efficiently while maintaining the same accuracy as the basic normalized cross correlation. Additionally, a KMF is also proposed to process fingerprinting localization results. It employs a new map matching algorithm to nonlinearize the linear location prediction process of Kalman filtering (KF that takes advantage of spatial proximities of consecutive localization results. With a calibration model integrated into an indoor map, the map matching algorithm corrects unreasonable prediction locations of the KF according to the building interior structure. Thus, more accurate prediction locations are obtained. Using these locations, the KMF considerably improves fingerprinting algorithm performance. Experimental results demonstrate that the FNCC algorithm with reduced computational complexity outperforms other neighbor selection algorithms and the KMF effectively improves location sensing accuracy by using indoor map information and spatial proximities of consecutive localization results.

Kalman/Map filtering-aided fast normalized cross correlation-based Wi-Fi fingerprinting location sensing.

Science.gov (United States)

Sun, Yongliang; Xu, Yubin; Li, Cheng; Ma, Lin

2013-11-13

A Kalman/map filtering (KMF)-aided fast normalized cross correlation (FNCC)-based Wi-Fi fingerprinting location sensing system is proposed in this paper. Compared with conventional neighbor selection algorithms that calculate localization results with received signal strength (RSS) mean samples, the proposed FNCC algorithm makes use of all the on-line RSS samples and reference point RSS variations to achieve higher fingerprinting accuracy. The FNCC computes efficiently while maintaining the same accuracy as the basic normalized cross correlation. Additionally, a KMF is also proposed to process fingerprinting localization results. It employs a new map matching algorithm to nonlinearize the linear location prediction process of Kalman filtering (KF) that takes advantage of spatial proximities of consecutive localization results. With a calibration model integrated into an indoor map, the map matching algorithm corrects unreasonable prediction locations of the KF according to the building interior structure. Thus, more accurate prediction locations are obtained. Using these locations, the KMF considerably improves fingerprinting algorithm performance. Experimental results demonstrate that the FNCC algorithm with reduced computational complexity outperforms other neighbor selection algorithms and the KMF effectively improves location sensing accuracy by using indoor map information and spatial proximities of consecutive localization results.

Water flow experiment using the PIV technique and the thermal hydraulic analysis on the cross-flow type mercury target model

International Nuclear Information System (INIS)

Haga, Katsuhiro; Terada, Atsuhiko; Kaminaga, Masanori; Hino, Ryutaro

2001-01-01

In this study the effectiveness of the cross-flow type mercury target structure was evaluated experimentally and analytically. The average water flow velocity field in the target mock-up model, which was fabricated with plexiglass, was measured at room temperature using the PIV (Particle Image Velocimetry) technique. The water flow analyses were conducted and the analytical results were compared with the experimental results. The experimental results showed that the cross-flow could be realized in the former part of the proton beam path where the heat load by the spallation reaction is large, and the analytical result of the water flow velocity field showed good correspondence to the experimental result in the case of the Reynolds number of more than 4.83 x 10 5 at the model inlet. With these results, the effectiveness of the cross-flow type mercury target structure and the present analysis code system was demonstrated. Then the mercury flow field and the temperature distribution in the target container were analyzed assuming the proton beam energy and power of 3 GeV and 5 MW. The analytical result showed that the cross-flow field of mercury, which is similar to the water flow field, could also be attained. (author)

Research on the flow field of undershot cross-flow water turbines using experiments and numerical analysis

International Nuclear Information System (INIS)

Nishi, Y; Inagaki, T; Li, Y; Omiya, R; Hatano, K

2014-01-01

The purpose of this research is to develop a water turbine appropriate for low-head open channels in order to effectively utilize the unused hydropower energy of rivers and agricultural waterways. The application of the cross-flow runner to open channels as an undershot water turbine has come under consideration and, to this end, a significant simplification was attained by removing the casings. However, the flow field of undershot cross-flow water turbines possesses free surfaces. This means that with the variation in the rotational speed, the water depth around the runner will change and flow field itself is significantly altered. Thus it is necessary to clearly understand the flow fields with free surfaces in order to improve the performance of this turbine. In this research, the performance of this turbine and the flow field were studied through experiments and numerical analysis. The experimental results on the performance of this turbine and the flow field were consistent with the numerical analysis. In addition, the inlet and outlet regions at the first and second stages of this water turbine were clarified

Alternative Antimicrobial Commercial Egg Washing Procedures.

Science.gov (United States)

Hudson, Lauren K; Harrison, Mark A; Berrang, Mark E; Jones, Deana R

2016-07-01

Commercial table eggs are washed prior to packaging. Standard wash procedures use an alkaline pH and warm water. If a cool water method could be developed that would still provide a microbiologically safe egg, the industry may save energy costs associated with water heating. Four wash procedures were evaluated for Salmonella reduction: pH 11 at 48.9°C (industry standard), pH 11 at ambient temperature (∼20°C), pH 6 at 48.9°C, and pH 6 at ambient temperature. Alkaline washes contained potassium hydroxide-based detergent, while pH 6 washes contained approximately 200 ppm of chlorine and a proprietary chlorine stabilizer (T-128). When eggs were inoculated by immersion in a cell suspension of Salmonella Enteritidis and Salmonella Typhimurium, all treatments resulted in a slight and similar reduction of Salmonella numbers (approximately 0.77 log CFU/ml of shell emulsion reduction). When eggs were inoculated by droplet on the shell surface, Salmonella counts were reduced by approximately 5 log CFU when washed with chlorine plus the chlorine stabilizer at both temperatures and with the alkaline wash at the high temperature. The reductions in Salmonella by these treatments were not significantly (P > 0.05) different from each other but were significantly (P pH 11 warm water wash and may be a viable option to reduce cost, increase shelf life, and slow pathogen growth in and on shell eggs.

Pollutants Characterization of Car Wash Wastewater

Directory of Open Access Journals (Sweden)

Hashim Nor Haslina

2016-01-01

Full Text Available The huge quantity of water consumed per car during washing cars yields the untreated effluents discharged to the stormwater system. Wastewater samples from snow car wash and two full hand service car wash station were analyzed for pH and the presence of PO43-,TP, O&G, alkalinity, TSS, NO3-, NO2-, COD and surfactant in accordance Standard Method of Water and Wastewater 2012. Two full hand wash service stations and one station of snow foam service were investigated in this study. Amongst the stations, snow foam car wash station indicates the highest concentration of PO43-, TP, O&G, TSS, COD and surfactant with the average value of 10.18 ± 0.87 mg/L, 30.93 ± 0.31 mg/L , 85.00 ± 0.64 mg/L 325.0 ± 0.6 mg/L, 485.0 ± 0.3 mg/L and 54.00 ± 2.50 mg/L as MBAS, respectively. Whereas, in parameters characterization in different stages throughout the car wash process, O&G was found to be the highest in pre soak stage, PO43-, TP, TSS and COD in washing stage and NO3- and NO2- in rinse stage. All parameters were compared to Environmental Quality (Industrial Effluent Regulations, 2009. There is a strong need to study on the characterization of car wash water in order to suggest the suitable treatment need for this type of wastewater.

Soil washing treatability study

International Nuclear Information System (INIS)

Krstich, M.

1995-12-01

Soil washing was identified as a viable treatment process option for remediating soil at the FEMP Environmental Management Project (FEMP). Little information relative to the specific application and potential effectiveness of the soil washing process exists that applies to the types of soil at the FEMP. To properly evaluate this process option in conjunction with the ongoing FEMP Remedial Investigation/Feasibility Study (RI/FS), a treatability testing program was necessary to provide a foundation for a detailed technical evaluation of the viability of the process. In August 1991, efforts were initiated to develop a work plan and experimental design for investigating the effectiveness of soil washing on FEMP soil. In August 1992, the final Treatability Study Work Plan for Operable Unit 5: Soil Washing (DOE 1992) was issued. This document shall be referenced throughout the remainder of this report as the Treatability Study Work Plan (TSWP). The purpose of this treatability study was to generate data to support initial screening and the detailed analysis of alternatives for the Operable Unit 5 FS

Factors Influencing HEPA Filter Performance

International Nuclear Information System (INIS)

Parsons, M.S.; Waggoner, Ch.A.

2009-01-01

Properly functioning HEPA air filtration systems depend on a variety of factors that start with the use of fully characterized challenge conditions for system design and then process control during operation. This paper addresses factors that should be considered during the design phase as well as operating parameters that can be monitored to ensure filter function and lifetime. HEPA filters used in nuclear applications are expected to meet design, fabrication, and performance requirements set forth in the ASME AG-1 standard. The DOE publication Nuclear Air Cleaning Handbook (NACH) is an additional guidance document for design and operation HEPA filter systems in DOE facilities. These two guidelines establish basic maximum operating parameters for temperature, maximum aerosol particle size, maximum particulate matter mass concentration, acceptable differential pressure range, and filter media velocity. Each of these parameters is discussed along with data linking variability of each parameter with filter function and lifetime. Temporal uncertainty associated with gas composition, temperature, and absolute pressure of the air flow can have a direct impact on the volumetric flow rate of the system with a corresponding impact on filter media velocity. Correlations between standard units of flow rate (standard meters per minute or cubic feet per minute) versus actual units of volumetric flow rate are shown for variations in relative humidity for a 70 deg. C to 200 deg. C temperature range as an example of gas composition that, uncorrected, will influence media velocity. The AG-1 standard establishes a 2.5 cm/s (5 feet per minute) ceiling for media velocities of nuclear grade HEPA filters. Data are presented that show the impact of media velocities from 2.0 to 4.0 cm/s media velocities (4 to 8 fpm) on differential pressure, filter efficiency, and filter lifetime. Data will also be presented correlating media velocity effects with two different particle size

Recirculating electric air filter

Science.gov (United States)

Bergman, W.

1985-01-09

An electric air filter cartridge has a cylindrical inner high voltage electrode, a layer of filter material, and an outer ground electrode formed of a plurality of segments moveably connected together. The outer electrode can be easily opened to remove or insert filter material. Air flows through the two electrodes and the filter material and is exhausted from the center of the inner electrode.

Probabilistics since WASH-1400

International Nuclear Information System (INIS)

Whitehead, N.E.

1980-01-01

Literature since the issuing of WASH-1400 reactor safety study shows that although the methodology has been attacked, it stands criticism well. Contrary to the aim of the study, which was to give a realistic, rather than a conservative risk estimate, there are many conservatisms in it. The strongly attacked treatment of common mode failure involving the square bounding model is shown here to be very likely to give correct results - and the applications of it in WASH-1400 do not often give results different from using the mean instead of the median. The Three-Mile Island accident is not such as to change the conclusions of WASH-1400 regarding core melt probabilities

Cross-flow shearing effects on the trajectory of highly buoyant bent-over plumes

Science.gov (United States)

Tohidi, Ali; Kaye, Nigel Berkeley; Gollner, Michael J.

2017-11-01

The dynamics of highly buoyant plumes in cross-flow is ubiquitous throughout both industrial and environmental phenomena. The rise of smoke from a chimney, wastewater discharge into river currents, and dispersion of wildfire plumes are only a few instances. There have been many previous studies investigating the behavior of jets and highly buoyant plumes in cross-flow. So far, however, very little attention has been paid to the role of shearing effects in the boundary layer on the plume trajectory, particularly on the rise height. Numerical simulations and dimensional analysis are conducted to characterize the near- and far-field behavior of a highly buoyant plume in a boundary layer cross-flow. The results show that shear in the cross-flow leads to large differences in the rise height of the plume in relation to a uniform cross-flow, especially at far-field. This material is based upon work supported by the National Science Foundation under Grant No.1200560. Any opinions, findings, and conclusions or recommendations expressed in the material are of the authors and do not necessarily reflect the views of NSF.

Effect of ribbed and smooth coolant cross-flow channel on film cooling

International Nuclear Information System (INIS)

Peng, Wei; Sun, Xiaokai; Jiang, Peixue; Wang, Jie

2017-01-01

Highlights: • Little different for plenum model and the cross-flow model at M = 0.5. • Crossflow model is much better than plenum model at M = 1.0, especially with ribs. • Coolant flow channel with V-shaped ribs has the best adiabatic film cooling. • Film cooling with the plenum model is better at M = 0.5 than at M = 1.0. • Crossflow model is better at M = 0.5 near film hole and at M = 1.0 for downstream. - Abstract: The influence of ribbed and unribbed coolant cross-flow channel on film cooling was investigated with the coolant supply being either a plenum-coolant feed or a coolant cross-flow feed. Validation experiments were conducted with comparison to numerical results using different RANS turbulence models showed that the RNG k–ε turbulence model and the RSM model gave closer predictions to the experimental data than the other RANS models. The results indicate that at a low blowing ratio of M = 0.5, the coolant supply channel structure has little effect on the film cooling. However, at a high blowing ratio of M = 1.0, the adiabatic wall film cooling effectiveness is significantly lower with the plenum feed than with the cross-flow feed, especially for the cases with ribs. The film cooling with the plenum model is better at M = 0.5 than at M = 1.0. The film cooling with the cross-flow model is better at a blowing ratio of M = 0.5 in the near hole region, while further downstream, it is better at M = 1.0. The results also show that the coolant cross-flow channel with V-shaped ribs has the best adiabatic film cooling effectiveness.

3D-CFD Simulation of Confined Cross-Flow Injection Process Using Single Piston Pump

Directory of Open Access Journals (Sweden)

M. Elashmawy

2017-12-01

Full Text Available Injection process into a confined cross flow is quite important for many applications including chemical engineering and water desalination technology. The aim of this study is to investigate the performance of the injection process into a confined cross-flow of a round pipe using a single piston injection pump. A computational fluid dynamics (CFD analysis has been carried out to investigate the effect of the locations of the maximum velocity and minimum pressure on the confined cross-flow process. The jet trajectory is analyzed and related to the injection pump shaft angle of rotation during the injection duty cycle by focusing on the maximum instant injection flow of the piston action. Results indicate a low effect of the jet trajectory within the range related to the injection pump operational conditions. Constant cross-flow was used and injection flow is altered to vary the jet to line flow ratio (QR. The maximum jet trajectory exhibits low penetration inside the cross-flow. The results showed three regions of the flow ratio effect zones with different behaviors. Results also showed that getting closer to the injection port causes a significant decrease on the locations of the maximum velocity and minimum pressure.

Effect of ribbed and smooth coolant cross-flow channel on film cooling

Energy Technology Data Exchange (ETDEWEB)

Peng, Wei; Sun, Xiaokai [Institute of Nuclear and New Energy Technology, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Tsinghua University, Beijing 100084 (China); Jiang, Peixue, E-mail: jiangpx@tsinghua.edu.cn [Key Laboratory for Thermal Science and Power Engineering of Ministry of Educations, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Wang, Jie [Institute of Nuclear and New Energy Technology, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Tsinghua University, Beijing 100084 (China)

2017-05-15

Highlights: • Little different for plenum model and the cross-flow model at M = 0.5. • Crossflow model is much better than plenum model at M = 1.0, especially with ribs. • Coolant flow channel with V-shaped ribs has the best adiabatic film cooling. • Film cooling with the plenum model is better at M = 0.5 than at M = 1.0. • Crossflow model is better at M = 0.5 near film hole and at M = 1.0 for downstream. - Abstract: The influence of ribbed and unribbed coolant cross-flow channel on film cooling was investigated with the coolant supply being either a plenum-coolant feed or a coolant cross-flow feed. Validation experiments were conducted with comparison to numerical results using different RANS turbulence models showed that the RNG k–ε turbulence model and the RSM model gave closer predictions to the experimental data than the other RANS models. The results indicate that at a low blowing ratio of M = 0.5, the coolant supply channel structure has little effect on the film cooling. However, at a high blowing ratio of M = 1.0, the adiabatic wall film cooling effectiveness is significantly lower with the plenum feed than with the cross-flow feed, especially for the cases with ribs. The film cooling with the plenum model is better at M = 0.5 than at M = 1.0. The film cooling with the cross-flow model is better at a blowing ratio of M = 0.5 in the near hole region, while further downstream, it is better at M = 1.0. The results also show that the coolant cross-flow channel with V-shaped ribs has the best adiabatic film cooling effectiveness.

Effects of fluid properties on the cross-flow between subchannels

International Nuclear Information System (INIS)

Azuma, Mie; Hotta, Akitoshi; Shirai, Hiroshi; Ninokata, Hisashi

2004-01-01

This study is one part of the fundamental research on the development of generalized boiling transition analysis methodology applicable to a wide variety of BWR-type fuel bundle geometries. In this study, quantitative identification of the void drift component in cross-flow is conducted by the combination of the Computational Fluid Dynamics (CFD) interface tracking technique and the Multiple Auto Regressive (MAR) method. The numerical model consists of two subchannels with a communication slit. The cross section is modeled in a reference of the Tapucu model, which is extracted from a symmetrical cell pair of actual square lattice fuel rod bundles. An air-water mixture in the slug and churn regimes at atmospheric pressure and room temperature is used as the working fluid. As a result, a concept on extraction of void drift and turbulent mixing components from cross-flow according to experimental data is confirmed by a numerical approach in which pressure is adjusted at each channel outlet using a model of two parallel channels with a communication slit. Criteria to extract components of the turbulent mixing and the void drift components from cross-flow assuming a multi-component mixture are proposed. Effects of surface tension and density ratio of water and air on the cross-flow between subchannels are investigated under conditions to maintain the gas-liquid evolution process based on the proposed criteria. The qualitative evaluation technique with dependency on surface tension and density ratio was proposed. It is expected to provide supplemental information which is difficult to obtain from experiments. (author)

Axial Fan Blade Vibration Assessment under Inlet Cross-Flow Conditions Using Laser Scanning Vibrometry

Directory of Open Access Journals (Sweden)

Till Heinemann

2017-08-01

Full Text Available In thermal power plants equipped with air-cooled condensers (ACCs, axial cooling fans operate under the influence of ambient flow fields. Under inlet cross-flow conditions, the resultant asymmetric flow field is known to introduce additional harmonic forces to the fan blades. This effect has previously only been studied numerically or by using blade-mounted strain gauges. For this study, laser scanning vibrometry (LSV was used to assess fan blade vibration under inlet cross-flow conditions in an adapted fan test rig inside a wind tunnel test section. Two co-rotating laser beams scanned a low-pressure axial fan, resulting in spectral, phase-resolved surface vibration patterns of the fan blades. Two distinct operating points with flow coefficients of 0.17 and 0.28 were examined, with and without inlet cross-flow influence. While almost identical fan vibration patterns were found for both reference operating points, the overall blade vibration increased by 100% at the low fan flow rate as a result of cross-flow, and by 20% at the high fan flow rate. While numerically predicted natural frequency modes could be confirmed from experimental data as minor peaks in the vibration amplitude spectrum, they were not excited significantly by cross-flow. Instead, primarily higher rotation-rate harmonics were amplified; that is, a synchronous blade-tip flapping was strongly excited at the blade-pass frequency.

Water motion and movement without sticking, weight loss and cross-contaminant in superhydrophobic glass tube.

Science.gov (United States)

Yuan, Jian-Jun; Jin, Ren-Hua

2010-02-10

We report that a simple fabrication of a superhydrophobic nanosurface consisted of a grass-like silica thin film on the inner wall of a glass tube and its feature in water motion and water movement. The glass tube with a superhydrophobic inner wall can make the water flow with friction-drag reduction and completely preventing water sticking. Transferring water by this tube did not cause weight loss at all. Therefore, aqueous solutions containing high content metal ions were cross-moved without washing the tube used and no cross-contamination occurred after cross-movement. Furthermore, in an inside diameter of 6.0 mm glass tube where the half-length of the inner surface is covered by superhydrophobic nanograss and the other half is an unmodified hydrophilic surface, the water droplets flowing down from the hydrophilic side can be stopped spontaneously at the hydrophilic-superhydrophobic boundary as if there is an invisible flow-stopping fence built inside the glass tube.

21 CFR 1250.87 - Wash water.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Wash water. 1250.87 Section 1250.87 Food and Drugs... Sanitation Facilities and Conditions on Vessels § 1250.87 Wash water. Where systems installed on vessels for wash water, as defined in § 1250.3(n), do not comply with the requirements of a potable water system...

Numerical solution of heat transfer process in a prismatic VHTR core accompanying bypass and cross flows

International Nuclear Information System (INIS)

Wang, Li; Liu, Qiusheng; Fukuda, Katsuya

2016-01-01

Highlights: • Three-dimensional CFD analysis is conducted for the thermal analysis in the reactor core. • Hot spot temperature, coolant channel outlet temperature distribution are affected by bypass flow. • Bypass gap size has significant influence on temperature and flow distribution in the core. • Cross flow has some effect on the temperature distribution of the coolant in the core due to flow mixing in the cross gaps. - Abstract: Bypass flow and cross flow gaps both exist in the core of a very high temperature gas-cooled reactor (VHTR), which is inevitable owing to tolerances in manufacturing, thermal expansion and irradiation shrinkage. The coolant mass flow rate distribution, temperature distribution, and hot spot temperature are significantly affected by bypass and cross flows. In the present study, three-dimensional CFD analysis is conducted for thermal analysis of the reactor core. A validation study for the turbulence model is performed by comparing the friction coefficient with published correlations. A sensitivity study of the near wall mesh is conducted to ensure mesh quality. Parametric studies are performed by changing the size of the bypass and cross gaps using a one-twelfth sector of a fuel block. Simulation results show the influence of the bypass gap size on temperature distribution and coolant mass flow rate distribution in the prismatic core. It is shown that the maximum fuel and coolant channel outlet temperatures increase with an increase in the gap size, which may lead to a structural risk to the fuel block. The cross flow is divided into two types: the cross flow from the bypass gap to the coolant channels and the cross flow from the high-pressure coolant channels to low-pressure coolant channels. These two types of flow have an opposing influence on the temperature gradient. It is found that the presence of the cross flow gaps may have a significant effect on the distribution of the coolant in the core due to flow mixing in the

TOMOGRAPHY OF PLASMA FLOWS IN THE UPPER SOLAR CONVECTION ZONE USING TIME-DISTANCE INVERSION COMBINING RIDGE AND PHASE-SPEED FILTERING

International Nuclear Information System (INIS)

Švanda, Michal

2013-01-01

The consistency of time-distance inversions for horizontal components of the plasma flow on supergranular scales in the upper solar convection zone is checked by comparing the results derived using two k-ω filtering procedures—ridge filtering and phase-speed filtering—commonly used in time-distance helioseismology. I show that both approaches result in similar flow estimates when finite-frequency sensitivity kernels are used. I further demonstrate that the performance of the inversion improves (in terms of a simultaneously better averaging kernel and a lower noise level) when the two approaches are combined together in one inversion. Using the combined inversion, I invert for horizontal flows in the upper 10 Mm of the solar convection zone. The flows connected with supergranulation seem to be coherent only for the top ∼5 Mm; deeper down there is a hint of change of the convection scales toward structures larger than supergranules

Flow in axisymmetric expansion in a catalytic converter

DEFF Research Database (Denmark)

Gotfredsen, Erik; Meyer, Knud Erik

The flow in an axisymmetric expansion (circular diffusor) is used in many different engineering applications, such as heat exchangers, catalytic converters and filters. These applications require a relatively uniform flow at the inlet. To minimise the pressure loss, an ideal solution would...... Velocimetry (PIV) is a unique method that resolve the entire cross flow. This type of flow is expected to have a fluctuating ‘jet’-like structure from the smaller inlet pipe into the larger converter. The fluctuations of the jet are difficult, if not impossible, to capture with standard time averaged models...

Numerical Study on Self-Cleaning Canister Filter With Add-On Filter Cap

Directory of Open Access Journals (Sweden)

Mohammed Akmal Nizam

2017-01-01

Full Text Available Filtration in a turbo machinery system such as a gas turbine will ensure that the air entering the inlet is free from contaminants that could bring damage to the main system. Self-cleaning filter systems for gas turbines are designed for continuously efficient flow filtration. A good filter would be able to maintain its effectiveness over a longer time period, prolonging the duration between filter replacements and providing lower pressure drop over its operating lifetime. With this goal in mind, the current study is focused on the difference in pressure loss of the benchmark Salutary Avenue Self-cleaning filter in comparison to a new design with an add-on filter cap. Geometry for the add-on filter cap will be based from Salutary Avenue Manufacturing Sdn.Bhd. SOLIDWORKS software was used to model the geometry of the filter, while simulation analysis on the flow through the filter was done using Computational Fluid Dynamic (CFD software. The simulations are based on a low velocity condition, in which the parameter for the inlet velocity are set at 0.032 m/s, 0.063 m/s, 0.094 m/s and 0.126 m/s respectively. From the simulation data obtained for the inlet velocities considered, the pressure drop reduction of the modified filter compared to the benchmark was found to be between 7.59% and 30.18%. All in all, the modification of the filter cap produced a lower pressure drop in comparison with the benchmark filter; an improvement of 27.02% for the total pressure drop was obtained.

Improving Ambient Wind Environments of a Cross-flow Wind Turbine near a Structure by using an Inlet Guide Structure and a Flow Deflector

Institute of Scientific and Technical Information of China (English)

Tadakazu TANINO; Shinichiro NAKAO; Genki UEBAYASHI

2005-01-01

A cross-flow wind turbine near a structure was tested for the performance. The results showed that the performance of a cross-flow wind turbine near a structure was up to 30% higher than the one without a structure.In addition, we tried to get higher performance of a cross-flow wind turbine by using an Inlet Guide Structure and a Flow Deflector. An Inlet Guide Structure was placed on the edge of a structure and a Flow Deflector was set near a cross-flow wind turbine and can improve ambient wind environments of the wind turbine, the maximum power coefficients were about 15 to 40% higher and the tip speed ratio range showing the high power coefficient was wide and the positive gradients were steep apparently.

Testing Of The Dual Rotary Filter System

International Nuclear Information System (INIS)

Herman, D.; Fowley, M.; Stefanko, D.

2011-01-01

The Savannah River National Laboratory (SRNL) installed and tested two hydraulically connected SpinTek rotary microfilter (RMF) units to determine the behavior of a multiple filter system. Both units were successfully controlled by a control scheme written in DELTA-V architecture by Savannah River Remediation (SRR) Process Control Engineering personnel. The control system was tuned to provide satisfactory response to changing conditions during the operation of the multi-filter system. Stability was maintained through the startup and shutdown of one of the filter units while the second was still in operation. The installation configuration originally proposed by the Small Colum Ion Exchange (SCIX) project of independent filter and motor mountings may be susceptible to vibration. Significant stiffening of the filter and motor mounts was required to minimize the vibration. Alignment of the motor to the filter was a challenge in this test configuration. The deployment configuration must be easy to manipulate and allow for fine adjustment. An analysis of the vibration signature of the test system identified critical speeds. Whether it corresponds to the resonance frequency of a rotor radial vibration mode that was excited by rotor unbalance is uncertain based upon the measurements. A relative motion series should be completed on the filter with the final shaft configuration to determine if the resonances exist in the final filter design. The instrumentation selected for deployment, including the concentrate discharge control valve and flow meters, performed well. Automation of the valve control integrated well with the control scheme and when used in concert with the other control variables, allowed automated control of the dual RMF system. The one area of concern with the instrumentation was the condition resulting when the filtrate flow meter operated with less than three gpm. This low flow was at the lower range of performance for the flow meter. This should not be

TESTING OF THE DUAL ROTARY FILTER SYSTEM

Energy Technology Data Exchange (ETDEWEB)

Herman, D.; Fowley, M.; Stefanko, D.

2011-08-29

The Savannah River National Laboratory (SRNL) installed and tested two hydraulically connected SpinTek rotary microfilter (RMF) units to determine the behavior of a multiple filter system. Both units were successfully controlled by a control scheme written in DELTA-V architecture by Savannah River Remediation (SRR) Process Control Engineering personnel. The control system was tuned to provide satisfactory response to changing conditions during the operation of the multi-filter system. Stability was maintained through the startup and shutdown of one of the filter units while the second was still in operation. The installation configuration originally proposed by the Small Colum Ion Exchange (SCIX) project of independent filter and motor mountings may be susceptible to vibration. Significant stiffening of the filter and motor mounts was required to minimize the vibration. Alignment of the motor to the filter was a challenge in this test configuration. The deployment configuration must be easy to manipulate and allow for fine adjustment. An analysis of the vibration signature of the test system identified critical speeds. Whether it corresponds to the resonance frequency of a rotor radial vibration mode that was excited by rotor unbalance is uncertain based upon the measurements. A relative motion series should be completed on the filter with the final shaft configuration to determine if the resonances exist in the final filter design. The instrumentation selected for deployment, including the concentrate discharge control valve and flow meters, performed well. Automation of the valve control integrated well with the control scheme and when used in concert with the other control variables, allowed automated control of the dual RMF system. The one area of concern with the instrumentation was the condition resulting when the filtrate flow meter operated with less than three gpm. This low flow was at the lower range of performance for the flow meter. This should not be

Local particle flux reversal under strongly sheared flow

International Nuclear Information System (INIS)

Terry, P.W.; Newman, D.E.; Ware, A.S.

2003-01-01

The advection of electron density by turbulent ExB flow with linearly varying mean yields a particle flux that can reverse sign at certain locations along the direction of magnetic shear. The effect, calculated for strong flow shear, resides in the density-potential cross phase. It is produced by the interplay between the inhomogeneities of magnetic shear and flow shear, but subject to a variety of conditions and constraints. The regions of reversed flux tend to wash out if the turbulence consists of closely spaced modes of different helicities, but survive if modes of a single helicity are relatively isolated. The reversed flux becomes negligible if the electron density response is governed by electron scales while the eigenmode is governed by ion scales. The relationship of these results to experimentally observe flux reversals is discussed

CROSS-FLOW ULTRAFILTRATION OF SECONDARY EFFLUENTS. MEMBRANE FOULING ANALYSIS

Directory of Open Access Journals (Sweden)

Luisa Vera

2014-12-01

Full Text Available The application of cross-flow ultrafiltration to regenerate secondary effluents is limited by membrane fouling. This work analyzes the influence of the main operational parameters (transmembrane pressure and cross-flow velocity about the selectivity and fouling observed in an ultrafiltration tubular ceramic membrane. The experimental results have shown a significant retention of the microcolloidal and soluble organic matter (52 – 54% in the membrane. The fouling analysis has defined the critical operational conditions where the fouling resistance is minimized. Such conditions can be described in terms of a dimensionless number known as shear stress number and its relationship with other dimensionless parameter, the fouling number.

A rigid porous filter and filtration method

Energy Technology Data Exchange (ETDEWEB)

Chiang, Ta-Kuan; Straub, Douglas, Straub L.; Dennis, Richard A.

1998-12-01

The present invention involves a porous rigid filter comprising a plurality of concentric filtration elements having internal flow passages and forming external flow passages there between. The present invention also involves a pressure vessel containing the filter for the removal of particulate from high pressure particulate containing gases, and further involves a method for using the filter to remove such particulate. The present filter has the advantage of requiring fewer filter elements due to the high surface area- to-volume ratio provided by the filter, requires a reduced pressure vessel size, and exhibits enhanced mechanical design properties, improved cleaning properties, configuration options, modularity and ease of fabrication.

Turbulent jet diffusion flame length evolution with cross flows in a sub-pressure atmosphere

International Nuclear Information System (INIS)

Wang, Qiang; Hu, Longhua; Zhang, Xiaozheng; Zhang, Xiaolei; Lu, Shouxiang; Ding, Hang

2015-01-01

Highlights: • Quantifying turbulent jet diffusion flame length with cross flows. • Unique data revealed for a sub-atmospheric pressure. • Non-dimensional global correlation proposed for flame trajectory-line length. - Abstract: This paper investigates the evolution characteristics of turbulent jet diffusion flame (flame trajectory-line length, flame height in vertical jet direction) with increasing cross flows in a sub-pressure (64 kPa) atmosphere. The combined effect of cross flow and a special sub-pressure atmosphere condition is revealed, where no data is available in the literatures. Experiments are carried out with a wind tunnel built specially in Lhasa city (altitude: 3650 m; pressure: 64 kPa) and in Hefei city (altitude: 50 m; pressure: 100 kPa), using nozzles with diameter of 3 mm, 4 mm and 5 mm and propane as fuel. It is found that, as cross flow air speed increases from zero, the flame trajectory-line length firstly decreases and then becomes almost stable (for relative small nozzle, 3 mm in this study) or increases (for relative large nozzle, 4 mm and 5 mm in this study) beyond a transitional critical cross flow air speed in normal pressure, however decreases monotonically until being blown-out in the sub-pressure atmosphere. The flame height in jet direction decreases monotonically with cross air flow speed and then reaches a steady value in both pressures. For the transitional state of flame trajectory-line length with increasing cross air flow speed, the corresponding critical cross flow air speed is found to be proportional to the fuel jet velocity, meanwhile independent of nozzle diameter. Correlation models are proposed for the flame height in jet direction and the flame trajectory-line length for both ambient pressures, which are shown to be in good agreement with the experimental results.

Constraining a compositional flow model with flow-chemical data using an ensemble-based Kalman filter

KAUST Repository

Gharamti, M. E.; Kadoura, A.; Valstar, J.; Sun, S.; Hoteit, Ibrahim

2014-01-01

Isothermal compositional flow models require coupling transient compressible flows and advective transport systems of various chemical species in subsurface porous media. Building such numerical models is quite challenging and may be subject to many sources of uncertainties because of possible incomplete representation of some geological parameters that characterize the system's processes. Advanced data assimilation methods, such as the ensemble Kalman filter (EnKF), can be used to calibrate these models by incorporating available data. In this work, we consider the problem of estimating reservoir permeability using information about phase pressure as well as the chemical properties of fluid components. We carry out state-parameter estimation experiments using joint and dual updating schemes in the context of the EnKF with a two-dimensional single-phase compositional flow model (CFM). Quantitative and statistical analyses are performed to evaluate and compare the performance of the assimilation schemes. Our results indicate that including chemical composition data significantly enhances the accuracy of the permeability estimates. In addition, composition data provide more information to estimate system states and parameters than do standard pressure data. The dual state-parameter estimation scheme provides about 10% more accurate permeability estimates on average than the joint scheme when implemented with the same ensemble members, at the cost of twice more forward model integrations. At similar computational cost, the dual approach becomes only beneficial after using large enough ensembles.

Constraining a compositional flow model with flow-chemical data using an ensemble-based Kalman filter

KAUST Repository

Gharamti, M. E.

2014-03-01

Isothermal compositional flow models require coupling transient compressible flows and advective transport systems of various chemical species in subsurface porous media. Building such numerical models is quite challenging and may be subject to many sources of uncertainties because of possible incomplete representation of some geological parameters that characterize the system\\'s processes. Advanced data assimilation methods, such as the ensemble Kalman filter (EnKF), can be used to calibrate these models by incorporating available data. In this work, we consider the problem of estimating reservoir permeability using information about phase pressure as well as the chemical properties of fluid components. We carry out state-parameter estimation experiments using joint and dual updating schemes in the context of the EnKF with a two-dimensional single-phase compositional flow model (CFM). Quantitative and statistical analyses are performed to evaluate and compare the performance of the assimilation schemes. Our results indicate that including chemical composition data significantly enhances the accuracy of the permeability estimates. In addition, composition data provide more information to estimate system states and parameters than do standard pressure data. The dual state-parameter estimation scheme provides about 10% more accurate permeability estimates on average than the joint scheme when implemented with the same ensemble members, at the cost of twice more forward model integrations. At similar computational cost, the dual approach becomes only beneficial after using large enough ensembles.

Hand Washing: Do's and Dont's

Science.gov (United States)

... hands frequently can help limit the transfer of bacteria, viruses and other microbes. Always wash your hands before: Preparing food or eating Treating wounds or caring for a sick person Inserting or removing contact lenses Always wash your hands after: Preparing food Using ...

Entropy Filtered Density Function for Large Eddy Simulation of Turbulent Reacting Flows

Science.gov (United States)

Safari, Mehdi

Analysis of local entropy generation is an effective means to optimize the performance of energy and combustion systems by minimizing the irreversibilities in transport processes. Large eddy simulation (LES) is employed to describe entropy transport and generation in turbulent reacting flows. The entropy transport equation in LES contains several unclosed terms. These are the subgrid scale (SGS) entropy flux and entropy generation caused by irreversible processes: heat conduction, mass diffusion, chemical reaction and viscous dissipation. The SGS effects are taken into account using a novel methodology based on the filtered density function (FDF). This methodology, entitled entropy FDF (En-FDF), is developed and utilized in the form of joint entropy-velocity-scalar-turbulent frequency FDF and the marginal scalar-entropy FDF, both of which contain the chemical reaction effects in a closed form. The former constitutes the most comprehensive form of the En-FDF and provides closure for all the unclosed filtered moments. This methodology is applied for LES of a turbulent shear layer involving transport of passive scalars. Predictions show favor- able agreements with the data generated by direct numerical simulation (DNS) of the same layer. The marginal En-FDF accounts for entropy generation effects as well as scalar and entropy statistics. This methodology is applied to a turbulent nonpremixed jet flame (Sandia Flame D) and predictions are validated against experimental data. In both flows, sources of irreversibility are predicted and analyzed.

Hand washing promotion for preventing diarrhoea

Science.gov (United States)

Ejemot-Nwadiaro, Regina I; Ehiri, John E; Arikpo, Dachi; Meremikwu, Martin M; Critchley, Julia A

2015-01-01

Background Diarrhoea accounts for 1.8 million deaths in children in low- and middle-income countries (LMICs). One of the identified strategies to prevent diarrhoea is hand washing. Objectives To assess the effects of hand washing promotion interventions on diarrhoeal episodes in children and adults. Search methods We searched the Cochrane Infectious Diseases Group Specialized Register (27 May 2015); CENTRAL (published in the Cochrane Library 2015, Issue 5); MEDLINE (1966 to 27 May 2015); EMBASE (1974 to 27 May 2015); LILACS (1982 to 27 May 2015); PsycINFO (1967 to 27 May 2015); Science Citation Index and Social Science Citation Index (1981 to 27 May 2015); ERIC (1966 to 27 May 2015); SPECTR (2000 to 27 May 2015); Bibliomap (1990 to 27 May 2015); RoRe, The Grey Literature (2002 to 27 May 2015); World Health Organization (WHO) International Clinical Trial Registry Platform (ICTRP), metaRegister of Controlled Trials (mRCT), and reference lists of articles up to 27 May 2015. We also contacted researchers and organizations in the field. Selection criteria Individually randomized controlled trials (RCTs) and cluster-RCTs that compared the effects of hand washing interventions on diarrhoea episodes in children and adults with no intervention. Data collection and analysis Three review authors independently assessed trial eligibility, extracted data, and assessed risk of bias. We stratified the analyses for child day-care centres or schools, community, and hospital-based settings. Where appropriate, incidence rate ratios (IRR) were pooled using the generic inverse variance method and random-effects model with 95% confidence intervals (CIs). We used the GRADE approach to assess the quality of evidence. Main results We included 22 RCTs: 12 trials from child day-care centres or schools in mainly high-income countries (54,006 participants), nine community-based trials in LMICs (15,303 participants), and one hospital-based trial among people with acquired immune deficiency

Environmental diagnosis of the washing machine motor

DEFF Research Database (Denmark)

Erichsen, Hanne K. Linnet

1997-01-01

An environmental diagnosis of the washing machine focusing on the motor is performed. The goal of the diagnosis is to designate environmental focus points in the product. The LCA of the washing machine showed impact potentials from the life cycle of the product (see: LCA of a washing machine). Th...... up 2%, Manually disassembling and recycling of metals, Reuse of motor in a new washing machine, aluminium wire instead of copper wire in the motor....

Modelling and measurement of wear particle flow in a dual oil filter system for condition monitoring

DEFF Research Database (Denmark)

Henneberg, Morten; Eriksen, René Lynge; Fich, Jens

2016-01-01

. The quantity of wear particles in gear oil is analysed with respect to system running conditions. It is shown that the model fits the data in terms of startup “particle burst” phenomenon, quasi-stationary conditions during operation, and clean-up filtration when placed out of operation. In order to establish...... boundary condition for particle burst phenomenon, the release of wear particles from a pleated mesh filter is measured in a test rig and included in the model. The findings show that a dual filter model, with startup phenomenon included, can describe trends in the wear particle flow observed in the gear...... particle generation is made possible by model parameter estimation and identification of an unintended lack of filter change. The model may also be used to optimise system and filtration performance, and to enable continuous condition monitoring....

Flow study in the cross sectional planes of a turbine scroll

Science.gov (United States)

Hamed, A.; Abdallah, S.; Tabakoff, W.

1977-01-01

A numerical study of the nonviscous flow characteristics in the cross-sectional planes of a radial inflow turbine scroll is presented. The velocity potential is used in the formulation to determine the flow velocity in these planes resulting from the continuous mass discharge. The effect of the through flow velocity is simulated by a continuous distribution of source/sink in the cross-section. A special iterative procedure is devised to handle the solution of the resulting Poisson's differential equation with Neumann boundary conditions in a domain with generally curved boundaries. The analysis is used to determine the effects of the radius of curvature, the location of the scroll section and its geometry on the flow characteristics in the turbine scroll.

Flow visualization studies of bodies with square cross sections

Science.gov (United States)

Chapman, G. T.; Clarkson, M. H.

1983-01-01

A water-tunnel study was conducted of four bodies. A solution of sodium fluorescein coating the body provided visualization of vortices and feeding sheets and isolated dots of methyl blue dye provided visualization of stream lines. These data, along with published oil-flow photos, were analyzed to develop the topological representation of the flows in cross-flow planes. Presented are the development of the flow along the body at fixed angles of attack and at a fixed body station with changes in angle of attack. Effects of roll angle, body corner radius, and nose bluntness are illustrated.

Transport of nanoparticles with dispersant through biofilm coated drinking water sand filters.

Science.gov (United States)

Li, Zhen; Aly Hassan, Ashraf; Sahle-Demessie, Endalkachew; Sorial, George A

2013-11-01

This article characterizes, experimentally and theoretically, the transport and retention of engineered nanoparticles (NP) through sand filters at drinking water treatment plants (DWTPs) under realistic conditions. The transport of four commonly used NPs (ZnO, CeO2, TiO2, and Ag, with bare surfaces and coating agents) through filter beds filled with sands from either acid washed and calcined, freshly acquired filter media, and used filter media from active filter media, were investigated. The study was conducted using water obtained upstream of the sand filter at DWTP. The results have shown that capping agents have a determinant importance in the colloidal stability and transport of NPs through the different filter media. The presence of the biofilm in used filter media increased adsorption of NPs but its effects in retaining capped NPs was less significant. The data was used to build a mathematical model based on the advection-dispersion equation. The model was used to simulate the performance of a scale-up sand filter and the effects on filtration cycle of traditional sand filtration system used in DWTPs. Published by Elsevier Ltd.

The structure of a jet in cross flow at low velocity ratios

International Nuclear Information System (INIS)

Gopalan, Shridhar; Abraham, Bruce M.; Katz, Joseph

2004-01-01

This paper examines in detail the flow structure and associated wall pressure fluctuations caused by the injection of a round, turbulent jet into a turbulent boundary layer. The velocity ratio, r, ratio of mean jet velocity to the mean cross flow, varies from 0.5 to 2.5 and the Reynolds number based on the cross flow speed and jet diameter is 1.9x10 4 . Particle image velocimetry is used to measure the flow and flush mounted pressure sensors installed at several locations used to determine the wall pressure. The results consist of sample instantaneous flow structures, distributions of mean velocity, vorticity and turbulence intensity, as well as wall pressure spectra. The flow structure depends strongly on the velocity ratio and there are two distinctly different regions. At low velocity ratios, namely r 2, the near-wall flow behind the jet resembles a Karman vortex street and the wall-normal vortical structures contain cross flow boundary layer vorticity. Autospectra of the pressure signals show that the effect of the jet is mainly in the 15-100 Hz range. At r 2, the wall pressure levels reach a plateau demonstrating the diminishing effect of the jet on the near-wall flow. Consistent with the flow structure, the highest wall pressure fluctuations occur off the jet centerline for r 2. Also, the advection speed of near-wall vortical structures increase with r at r 2 it is a constant

An Application of Filtered Renewal Processes in Hydrology

Directory of Open Access Journals (Sweden)

Mario Lefebvre

2014-01-01

Full Text Available Filtered renewal processes are used to forecast daily river flows. For these processes, contrary to filtered Poisson processes, the time between consecutive events is not necessarily exponentially distributed, which is more realistic. The model is applied to obtain one- and two-day-ahead forecasts of the flows of the Delaware and Hudson Rivers, both located in the United States. Better results are obtained than with filtered Poisson processes, which are often used to model river flows.

Calibration of the Dodewaard downcomer thermocouple cross-correlation flow-rate measurements

Energy Technology Data Exchange (ETDEWEB)

Stekelenburg, A J.C. [Technische Univ. Delft (Netherlands). Interfacultair Reactor Inst.; Hagen, T.H.J.J. van der [Technische Univ. Delft (Netherlands). Interfacultair Reactor Inst.; Akker, H.E.A. van den [Technische Univ. Delft (Netherlands). Lab. voor Fysische Technologie

1992-12-01

The cross-correlation flow measurement technique, applied for measuring the coolant flow rate in a nuclear reactor, was calibrated with the use of numerical simulations of turbulent flow. The three-dimensional domain was collapsed into two dimensions. With a two-dimensional calculation of steady-state flow with transient thermal characteristics the response of thermocouples to a temperature variation was calculated. By cross-correlating the calculated thermocouple responses, the link between total flow rate and measured transit times was made. Three calibration points were taken in the range of 579 kg/s to 1477 kg/s. In this range, the product of the calculated transit time and the mass flow-rate is constant up to +3.5% and -2.4%. The reliability of the calibration was estimated at {+-}4.6%. The influence of the inlet boundary conditions, and the modelling of the flow in the upper part of the downcomer channel on the calibration result is shown to be small. A measured velocity profile effect was successfully predicted. (orig.).

Radionuclide content of Las Vegas wash sediments

International Nuclear Information System (INIS)

Rudin, M.J.; Meyers, A.M.; Johnson, W.H.

1996-01-01

The Las Vegas Wash is an excavated waterway channel which drains all surface water and effluent discharge from sewage-treatment facilities from the greater Las Vegas Metropolitan Area to Lake Mead. Runoff and erosion processes are expected to transport man-made radioactivity that was deposited over the past several decades in the Las Vegas Valley. Additionally, radionuclides disposed of via the city's sanitary system are expected to accumulate in the Wash sediments. Fine and coarse sediment samples were collected at 100 m intervals and analyzed to determine the distribution of alpha- and gamma-emitting radionuclides in the lower 5,500 in of the Las Vegas Wash. Results indicate little accumulation of long-lived fission products in upstream Wash sediments. However, trace amounts of fission products measured in downstream sediments suggest the resuspension and transport of radioactive particulate matter within the Wash. Levels of naturally-occurring radionuclides found in Wash sediments were found to be consistent with levels typically found in southeast Nevada soils

Anaerobic treatment of distillery spent wash - a study on upflow anaerobic fixed film bioreactor.

Science.gov (United States)

Acharya, Bhavik K; Mohana, Sarayu; Madamwar, Datta

2008-07-01

Anaerobic digestion of wastewater from a distillery industry having very high COD (1,10,000-1,90,000 mg/L) and BOD (50,000-60,000 mg/L) was studied in a continuously fed, up flow fixed film column reactor using different support materials such as charcoal, coconut coir and nylon fibers under varying hydraulic retention time and organic loading rates. The seed consortium was prepared by enrichment with distillery spent wash in a conventional type reactor having working capacity of 3 L and was used for charging the anaerobic column reactor. Amongst the various support materials studied the reactor having coconut coir could treat distillery spent wash at 8d hydraulic retention time with organic loading rate of 23.25 kg COD m(-3)d(-1) leading to 64% COD reduction with biogas production of 7.2 m3 m(-3)d(-1) having high methane yield without any pretreatment or neutralization of the distillery spent wash. This study indicates fixed film biomethanation of distillery spent wash using coconut coir as the support material appears to be a cost effective and promising technology for mitigating the problems caused by distillery effluent.

An Analytical Model for Multilayer Well Production Evaluation to Overcome Cross-Flow Problem

KAUST Repository

Hakiki, Farizal; Wibowo, Aris T.; Rahmawati, Silvya D.; Yasutra, Amega; Sukarno, Pudjo

2017-01-01

One of the major concerns in a multi-layer system is that interlayer cross-flow may occur if reservoir fluids are produced from commingled layers that have unequal initial pressures. Reservoir would commonly have bigger average reservoir pressure (pore fluid pressure) as it goes deeper. The phenomenon is, however, not followed by the reservoir productivity or injectivity. The existence of reservoir with quite low average-pressure and high injectivity would tend experiencing the cross-flow problem. It is a phenomenon of fluid from bottom layer flowing into upper layer. It would strict upper-layer fluid to flow into wellbore. It is as if there is an injection treatment from bottom layer. The study deploys productivity index an approach parameter taking into account of cross-flow problem instead of injectivity index since it is a production well. The analytical study is to model the reservoir multilayer by addressing to avoid cross-flow problem. The analytical model employed hypothetical and real field data to test it. The scope of this study are: (a) Develop mathematical-based solution to determine the production rate from each layer; (b) Assess different scenarios to optimize production rate, those are: pump setting depth and performance of in-situ choke (ISC) installation. The ISC is acting as an inflow control device (ICD) alike that help to reduce cross-flow occurrence. This study employed macro program to write the code and develop the interface. Fast iterative procedure happens on solving the analytical model. Comparison results recognized that the mathematical-based solution shows a good agreement with the commercial software derived results.

An Analytical Model for Multilayer Well Production Evaluation to Overcome Cross-Flow Problem

KAUST Repository

Hakiki, Farizal

2017-10-17

One of the major concerns in a multi-layer system is that interlayer cross-flow may occur if reservoir fluids are produced from commingled layers that have unequal initial pressures. Reservoir would commonly have bigger average reservoir pressure (pore fluid pressure) as it goes deeper. The phenomenon is, however, not followed by the reservoir productivity or injectivity. The existence of reservoir with quite low average-pressure and high injectivity would tend experiencing the cross-flow problem. It is a phenomenon of fluid from bottom layer flowing into upper layer. It would strict upper-layer fluid to flow into wellbore. It is as if there is an injection treatment from bottom layer. The study deploys productivity index an approach parameter taking into account of cross-flow problem instead of injectivity index since it is a production well. The analytical study is to model the reservoir multilayer by addressing to avoid cross-flow problem. The analytical model employed hypothetical and real field data to test it. The scope of this study are: (a) Develop mathematical-based solution to determine the production rate from each layer; (b) Assess different scenarios to optimize production rate, those are: pump setting depth and performance of in-situ choke (ISC) installation. The ISC is acting as an inflow control device (ICD) alike that help to reduce cross-flow occurrence. This study employed macro program to write the code and develop the interface. Fast iterative procedure happens on solving the analytical model. Comparison results recognized that the mathematical-based solution shows a good agreement with the commercial software derived results.

Cellular automata model for urban road traffic flow considering pedestrian crossing street

Science.gov (United States)

Zhao, Han-Tao; Yang, Shuo; Chen, Xiao-Xu

2016-11-01

In order to analyze the effect of pedestrians' crossing street on vehicle flows, we investigated traffic characteristics of vehicles and pedestrians. Based on that, rules of lane changing, acceleration, deceleration, randomization and update are modified. Then we established two urban two-lane cellular automata models of traffic flow, one of which is about sections with non-signalized crosswalk and the other is on uncontrolled sections with pedestrians crossing street at random. MATLAB is used for numerical simulation of the different traffic conditions; meanwhile space-time diagram and relational graphs of traffic flow parameters are generated and then comparatively analyzed. Simulation results indicate that when vehicle density is lower than around 25 vehs/(km lane), pedestrians have modest impact on traffic flow, whereas when vehicle density is higher than about 60 vehs/(km lane), traffic speed and volume will decrease significantly especially on sections with non-signal-controlled crosswalk. The results illustrate that the proposed models reconstruct the traffic flow's characteristic with the situation where there are pedestrians crossing and can provide some practical reference for urban traffic management.

Social determinants of good hand-washing practice (GHP) among adolescents in a rural Indian community.

Science.gov (United States)

Dobe, Madhumita; Mandal, Ram Narayan; Jha, Ayan

2013-01-01

A cross-sectional study was conducted in 5 randomly selected villages to assess prevalence of good hand-washing practice (GHP) among adolescents, and describe the social determinants. The prevalence of adolescent GHP was 32.1% (95% CI = 27.1, 37.1). Logistic regression established 5 significant positive predictors-maternal GHP, presence of sanitary latrine, availability of soap at hand-washing locations, in-house water supply, and higher per capita income. Our research provides a scope for better understanding of the socioeconomic determinants of GHP in a rural Indian setting, and may find implications in the Total Sanitation Campaign launched by Government of India.

MR angiography with a matched filter

International Nuclear Information System (INIS)

De Castro, J.B.; Riederer, S.J.; Lee, J.N.

1987-01-01

The technique of matched filtering was applied to a series of cine MR images. The filter was devised to yield a subtraction angiographic image in which direct current components present in the cine series are removed and the signal-to-noise ratio (S/N) of the vascular structures is optimized. The S/N of a matched filter was compared with that of a simple subtraction, in which an image with high flow is subtracted from one with low flow. Experimentally, a range of results from minimal improvement to significant (60%) improvement in S/N was seen in the comparisons of matched filtered subtraction with simple subtraction

Particle Filtering Methods for Incorporating Intelligence Updates

Science.gov (United States)

2017-03-01

past time steps. 3.2.1 Particle Filtering through Bayesian Bootstrap Sampling Although SIS helps resolve the computational and complexity issues...variables. This insight was called the Bayesian bootstrap filter, or more commonly called the particle filter. Multiple particles are sampled from an...2012) 16 maps of drug flow into the United States. Business Insider Online, (July 8), http://www.businessinsider.com/16-maps-of-drug-flow-into-the

CANFLEX fuel bundle cross-flow endurance test 2 (test procedure)

Energy Technology Data Exchange (ETDEWEB)

Hong, Sung Deok; Chung, C. H.; Chang, S. K. [Korea Atomic Energy Research Institute, Taejon (Korea)

1999-04-01

This report describes test procedure of cross-flow 2 test for CANFLEX fuel. In October 1996. a cross-flow test was successfully performed in the KAERI Hot Test Loop for four hours at a water flow rate of 31kg/s, temperature of 266 deg C and inlet pressure of 11MPa, but it is requested more extended time periods to determine a realistic operational margin for the CANFLEX bundle during abnormal refuelling operations. The test shall be conducted for twenty two hours under the reactor conditions. After an initial period of ten hours, the test shall be stopped at the intervals of four hours for bundle inspection and inspect the test bundle end-plate to end-cap welds for failure or crack propagation using liquid penetrant examination. 2 refs., 1 fig. (Author)

On performing of interference technique based on self-adjusting Zernike filters (SA-AVT method) to investigate flows and validate 3D flow numerical simulations

Science.gov (United States)

Pavlov, Al. A.; Shevchenko, A. M.; Khotyanovsky, D. V.; Pavlov, A. A.; Shmakov, A. S.; Golubev, M. P.

2017-10-01

We present a method for and results of determination of the field of integral density in the structure of flow corresponding to the Mach interaction of shock waves at Mach number M = 3. The optical diagnostics of flow was performed using an interference technique based on self-adjusting Zernike filters (SA-AVT method). Numerical simulations were carried out using the CFS3D program package for solving the Euler and Navier-Stokes equations. Quantitative data on the distribution of integral density on the path of probing radiation in one direction of 3D flow transillumination in the region of Mach interaction of shock waves were obtained for the first time.

Wash water waste pretreatment system study

Science.gov (United States)

1976-01-01

The use of real wash water had no adverse effect on soap removal when an Olive Leaf soap based system was used; 96 percent of the soap was removed using ferric chloride. Numerous chemical agents were evaluated as antifoams for synthetic wash water. Wash water surfactants used included Olive Leaf Soap, Ivory Soap, Neutrogena and Neutrogena Rain Bath Gel, Alipal CO-436, Aerosol 18, Miranol JEM, Palmeto, and Aerosol MA-80. For each type of soapy wash water evaluated, at least one antifoam capable of causing nonpersistent foam was identified. In general, the silicones and the heavy metal ions (i.e., ferric, aluminum, etc.) were the most effective antifoams. Required dosage was in the range of 50 to 200 ppm.

Enhanced sludge washing evaluation plan

Energy Technology Data Exchange (ETDEWEB)

Jensen, R.D.

1994-09-01

The Tank Waste Remediation System (TWRS) Program mission is to store, treat, and immobilize highly radioactive Hanford Site waste (current and future tank waste and the strontium/cesium capsules) in an environmentally sound, safe, and cost-effective manner. The scope of the TWRS Waste Pretreatment Program is to treat tank waste and separate that waste into HLW and LLW fractions and provide additional treatment as required to feed LLW and HLW immobilization facilities. Enhanced sludge washing was chosen as the baseline process for separating Hanford tank waste sludge. Section 1.0 briefly discusses the purpose of the evaluation plan and provides the background that led to the choice of enhanced sludge washing as the baseline process. Section 2.0 provides a brief summary of the evaluation plan details. Section 3.0 discusses, in some detail, the technical work planned to support the evaluation of enhanced sludge washing. Section 4.0 briefly discusses the potential important of policy issues to the evaluation. Section 5.0 discusses the methodology to be used in the evaluation process. Section 6.0 summarizes the milestones that have been defined to complete the enhanced sludge washing evaluation and provides a summary schedule to evaluate the performance of enhanced sludge washing. References are identified in Section 7.0, and additional schedule and milestone information is provided in the appendices.

Enhanced sludge washing evaluation plan

International Nuclear Information System (INIS)

Jensen, R.D.

1994-09-01

The Tank Waste Remediation System (TWRS) Program mission is to store, treat, and immobilize highly radioactive Hanford Site waste (current and future tank waste and the strontium/cesium capsules) in an environmentally sound, safe, and cost-effective manner. The scope of the TWRS Waste Pretreatment Program is to treat tank waste and separate that waste into HLW and LLW fractions and provide additional treatment as required to feed LLW and HLW immobilization facilities. Enhanced sludge washing was chosen as the baseline process for separating Hanford tank waste sludge. Section 1.0 briefly discusses the purpose of the evaluation plan and provides the background that led to the choice of enhanced sludge washing as the baseline process. Section 2.0 provides a brief summary of the evaluation plan details. Section 3.0 discusses, in some detail, the technical work planned to support the evaluation of enhanced sludge washing. Section 4.0 briefly discusses the potential important of policy issues to the evaluation. Section 5.0 discusses the methodology to be used in the evaluation process. Section 6.0 summarizes the milestones that have been defined to complete the enhanced sludge washing evaluation and provides a summary schedule to evaluate the performance of enhanced sludge washing. References are identified in Section 7.0, and additional schedule and milestone information is provided in the appendices

30 CFR 206.459 - Allocation of washed coal.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Allocation of washed coal. 206.459 Section 206... MANAGEMENT PRODUCT VALUATION Indian Coal § 206.459 Allocation of washed coal. (a) When coal is subjected to washing, the washed coal must be allocated to the leases from which it was extracted. (b) When the net...

30 CFR 206.260 - Allocation of washed coal.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Allocation of washed coal. 206.260 Section 206... MANAGEMENT PRODUCT VALUATION Federal Coal § 206.260 Allocation of washed coal. (a) When coal is subjected to washing, the washed coal must be allocated to the leases from which it was extracted. (b) When the net...

Application of the extended Kalman filtering for the estimation of core coolant flow rate in pressurized water reactors

International Nuclear Information System (INIS)

Shieh, D.J.; Upadhyaya, B.R.

1986-01-01

In-core neutron detector and core-exit temperature signals in a pressurized water reactor (PWR) satisfy the condition of observability of the core dynamic system, and can be used to estimate nonmeasurable state variables and model parameters. The extension of the Kalman filtering technique is very useful for direct parameter estimation. This approach is applied to the determination of core coolant mass flow rate in PWRs and is evaluated using in-core measurements at the Loss-of-Fluid Test (LOFT) reactor. The influence of model uncertainties on the estimation accuracy was studied using the ambiguity function analysis. A sequential discretization method was developed to achieve faster convergence to the true value, avoiding model discretization at each sample point. The performance of the extended Kalman filter and the computational innovations were evaluated using a reduced order core dynamic model of the LOFT reactor and random data simulation. The technique was then applied to the determination of LOFT core coolant flow rate from operational data at 100% and 65% flow conditions

The fluence research of filter material for fast neutron fluence measurement

International Nuclear Information System (INIS)

Tang Xiding

2010-01-01

When the fast neutron fluence is measured by radioactivation techniques in the nuclear reactor the fast neutron is also filtered a little by the thermal neutron filter material, and if the filter material thickness increase the filtered fast neutron increases therewith. For fast neutron fluenc measurement, there are only cadmium, boron and gadolinium three elements filtering fluence can be calculated ordinarily. In order to calculate the filtered fast neutron fluence of the all elements in the filter material, the many total cross sections of nuclides had checked out from nuclear cross section data library, converted them into the same energy group structure, then element's total cross section, compound's total cross section and multilayer filters' total cross section had calculated from these total cross sections with same energy group structure, a new cross section data library can be obtained lastly through merging these cross sections into the old cross section data library used for neutron fluence measurement. The calculation analysis indicates that the results of the unit 2 surveillance capsule U of DAYA Bay NPP and the unit 1 surveillance capsule A of the Second Nuclear Power Plant of Qinshan by considering the all elements subtracting iron are smaller about 1.5% and 2.6% respectively than the ones only to consider cadmium, boron. The old measured results accord with the new values under the measurement uncertainty, are reliable. The new results are more accuracy. (authors)

Effectiveness-ntu computation with a mathematical model for cross-flow heat exchangers

Directory of Open Access Journals (Sweden)

H. A. Navarro

2007-12-01

Full Text Available Due to the wide range of design possibilities, simple manufactured, low maintenance and low cost, cross-flow heat exchangers are extensively used in the petroleum, petrochemical, air conditioning, food storage, and others industries. In this paper a mathematical model for cross-flow heat exchangers with complex flow arrangements for determining epsilon -NTU relations is presented. The model is based on the tube element approach, according to which the heat exchanger outlet temperatures are obtained by discretizing the coil along the tube fluid path. In each cross section of the element, tube-side fluid temperature is assumed to be constant because the heat capacity rate ratio C*=Cmin/Cmax tends toward zero in the element. Thus temperature is controlled by effectiveness of a local element corresponding to an evaporator or a condenser-type element. The model is validated through comparison with theoretical algebraic relations for single-pass cross-flow arrangements with one or more rows. Very small relative errors are obtained showing the accuracy of the present model. epsilon -NTU curves for several complex circuit arrangements are presented. The model developed represents a useful research tool for theoretical and experimental studies on heat exchangers performance.

INFLUENCE OF RESIDENCE-TIME DISTRIBUTION ON A SURFACE-RENEWAL MODEL OF CONSTANT-PRESSURE CROSS-FLOW MICROFILTRATION

Directory of Open Access Journals (Sweden)

W. Zhang

2015-03-01

Full Text Available Abstract This work examines the influence of the residence-time distribution (RTD of surface elements on a model of cross-flow microfiltration that has been proposed recently (Hasan et al., 2013. Along with the RTD from the previous work (Case 1, two other RTD functions (Cases 2 and 3 are used to develop theoretical expressions for the permeate-flux decline and cake buildup in the filter as a function of process time. The three different RTDs correspond to three different startup conditions of the filtration process. The analytical expressions for the permeate flux, each of which contains three basic parameters (membrane resistance, specific cake resistance and rate of surface renewal, are fitted to experimental permeate flow rate data in the microfiltration of fermentation broths in laboratory- and pilot-scale units. All three expressions for the permeate flux fit the experimental data fairly well with average root-mean-square errors of 4.6% for Cases 1 and 2, and 4.2% for Case 3, respectively, which points towards the constructive nature of the model - a common feature of theoretical models used in science and engineering.

Regular use of a hand cream can attenuate skin dryness and roughness caused by frequent hand washing

Directory of Open Access Journals (Sweden)

Kampf Günter

2006-02-01

Full Text Available Abstract Background Aim of the study was to determine the effect of the regular use of a hand cream after washing hands on skin hydration and skin roughness. Methods Twenty-five subjects washed hands and forearms with a neutral soap four times per day, for 2 minutes each time, for a total of two weeks. One part of them used a hand cream after each hand wash, the others did not (cross over design after a wash out period of two weeks. Skin roughness and skin hydration were determined on the forearms on days 2, 7, 9 and 14. For skin roughness, twelve silicon imprint per subject and time point were taken from the stratum corneum and assessed with a 3D skin analyzer for depth of the skin relief. For skin hydration, five measurements per subject and time point were taken with a corneometer. Results Washing hands lead to a gradual increase of skin roughness from 100 (baseline to a maximum of 108.5 after 9 days. Use of a hand cream after each hand wash entailed a decrease of skin roughness which the lowest means after 2 (94.5 and 14 days (94.8. Skin hydration was gradually decreased after washing hands from 79 (baseline to 65.5 after 14 days. The hand wash, followed by use of a hand cream, still decreased skin hydration after 2 days (76.1. Over the next 12 days, however, skin hydration did not change significantly (75.6 after 14 days. Conclusion Repetitive and frequent hand washing increases skin dryness and roughness. Use of a hand cream immediately after each hand wash can confine both skin dryness and skin roughness. Regular use of skin care preparations should therefore help to prevent both dry and rough skin among healthcare workers in clinical practice.

Adaptive Filtering Queueing for Improving Fairness

Directory of Open Access Journals (Sweden)

Jui-Pin Yang

2015-06-01

Full Text Available In this paper, we propose a scalable and efficient Active Queue Management (AQM scheme to provide fair bandwidth sharing when traffic is congested dubbed Adaptive Filtering Queueing (AFQ. First, AFQ identifies the filtering level of an arriving packet by comparing it with a flow label selected at random from the first level to an estimated level in the filtering level table. Based on the accepted traffic estimation and the previous fair filtering level, AFQ updates the fair filtering level. Next, AFQ uses a simple packet-dropping algorithm to determine whether arriving packets are accepted or discarded. To enhance AFQ’s feasibility in high-speed networks, we propose a two-layer mapping mechanism to effectively simplify the packet comparison operations. Simulation results demonstrate that AFQ achieves optimal fairness when compared with Rotating Preference Queues (RPQ, Core-Stateless Fair Queueing (CSFQ, CHOose and Keep for responsive flows, CHOose and Kill for unresponsive flows (CHOKe and First-In First-Out (FIFO schemes under a variety of traffic conditions.

A Spatial-Filtering Zero-Inflated Approach to the Estimation of the Gravity Model of Trade

Directory of Open Access Journals (Sweden)

Rodolfo Metulini

2018-02-01

Full Text Available Nonlinear estimation of the gravity model with Poisson-type regression methods has become popular for modelling international trade flows, because it permits a better accounting for zero flows and extreme values in the distribution tail. Nevertheless, as trade flows are not independent from each other due to spatial and network autocorrelation, these methods may lead to biased parameter estimates. To overcome this problem, eigenvector spatial filtering (ESF variants of the Poisson/negative binomial specifications have been proposed in the literature on gravity modelling of trade. However, no specific treatment has been developed for cases in which many zero flows are present. This paper contributes to the literature in two ways. First, by employing a stepwise selection criterion for spatial filters that is based on robust (sandwich p-values and does not require likelihood-based indicators. In this respect, we develop an ad hoc backward stepwise function in R. Second, using this function, we select a reduced set of spatial filters that properly accounts for importer-side and exporter-side specific spatial effects, as well as network effects, both at the count and the logit processes of zero-inflated methods. Applying this estimation strategy to a cross-section of bilateral trade flows between a set of 64 countries for the year 2000, we find that our specification outperforms the benchmark models in terms of model fitting, both considering the AIC and in predicting zero (and small flows.

Spatial heterogeneity of biofouling under different cross-flow velocities in reverse osmosis membrane systems

KAUST Repository

Farhat, Nadia; Staal, M.; Bucs, Szilard; Van Loosdrecht, M.C.M.; Vrouwenvelder, Johannes S.

2016-01-01

the spatial heterogeneity of biofilm development over the membrane fouling simulator (MFS) length (inlet and outlet part) at three different cross-flow velocities (0.08, 0.12 and 0.16 m/s). The MFS contained sheets of membrane and feed spacer and simulatedComparison of the inlet and outlet position of the MFS showed a more (i) heterogeneous biofilm distribution and a (ii) higher biological activity at the inlet side (first 2.5 cm) for all cross-flow velocities. The lowest cross-flow velocity had

DEVELOPMENT OF AN ADHESIVE CANDLE FILTER SAFEGUARD DEVICE; F

International Nuclear Information System (INIS)

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

2002-01-01

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

High-efficiency particulate air (HEPA) filter performance following service and radiation exposure

International Nuclear Information System (INIS)

Jones, L.R.

1975-01-01

Small HEPA filters were exposed to a 60 Co source with a radiation strength of 3 x 10 7 rads per hour and then exposed to steam--air mixtures at several times filter design flow, followed by extended exposure to steam and air at reduced flow. Additional filters were exposed to air flow in a reactor confinement system and then similarly tested with steam--air mixture flows. The test data and calculated effects of filter pluggage with moisture on confinement system performance following potential reactor accidents are described. Gamma radiation exposure impaired the performance of new filters only slightly and temporarily improved performance of service aged filters. Normal confinement system service significantly impaired filter performance although not sufficiently to prevent adequate performance of the SRP confinement system following an unlikely reactor accident. Calculations based on measured filter pluggage indicate that during an accident air flow could be reduced approximately 50 percent with service-degraded HEPA filters present, or approximately 10 percent with new filters damaged by the radiation exposure. (U.S.)

Studies on the crossed flow type MHD turbines

International Nuclear Information System (INIS)

Hori, Toshihiro; Katsurai, Makoto

1981-01-01

The studies on crossed flow type MHD turbines were performed to improve its characteristics. Two-dimensional models were considered for the analytical studies. To compensate the edge effect of magnetic field, the magnetic field gradient by tapering was considered. An iron-core structure and an air-core structure were investigated. It was found that the ideal characteristics can be obtained when there is the tapered length more than one wave length. Various methods for the improvement of magnetic field were studied in the case of practical crossed flow type MHD turbines. The methods were the adjustment with an iron-core, and the adoption of a curved channel. It can be expected to obtain the internal efficiency of more than 70 percent, when the number of pole-pairs is more than 10 and the radius of curvature of a few times of rotor radius is given to a curved channel. (Kato, T.)

A nowcasting technique based on application of the particle filter blending algorithm

Science.gov (United States)

Chen, Yuanzhao; Lan, Hongping; Chen, Xunlai; Zhang, Wenhai

2017-10-01

To improve the accuracy of nowcasting, a new extrapolation technique called particle filter blending was configured in this study and applied to experimental nowcasting. Radar echo extrapolation was performed by using the radar mosaic at an altitude of 2.5 km obtained from the radar images of 12 S-band radars in Guangdong Province, China. The first bilateral filter was applied in the quality control of the radar data; an optical flow method based on the Lucas-Kanade algorithm and the Harris corner detection algorithm were used to track radar echoes and retrieve the echo motion vectors; then, the motion vectors were blended with the particle filter blending algorithm to estimate the optimal motion vector of the true echo motions; finally, semi-Lagrangian extrapolation was used for radar echo extrapolation based on the obtained motion vector field. A comparative study of the extrapolated forecasts of four precipitation events in 2016 in Guangdong was conducted. The results indicate that the particle filter blending algorithm could realistically reproduce the spatial pattern, echo intensity, and echo location at 30- and 60-min forecast lead times. The forecasts agreed well with observations, and the results were of operational significance. Quantitative evaluation of the forecasts indicates that the particle filter blending algorithm performed better than the cross-correlation method and the optical flow method. Therefore, the particle filter blending method is proved to be superior to the traditional forecasting methods and it can be used to enhance the ability of nowcasting in operational weather forecasts.

Biological activation of carbon filters.

Science.gov (United States)

Seredyńska-Sobecka, Bozena; Tomaszewska, Maria; Janus, Magdalena; Morawski, Antoni W

2006-01-01

To prepare biological activated carbon (BAC), raw surface water was circulated through granular activated carbon (GAC) beds. Biological activity of carbon filters was initiated after about 6 months of filter operation and was confirmed by two methods: measurement of the amount of biomass attached to the carbon and by the fluorescein diacetate (FDA) test. The effect of carbon pre-washing on WG-12 carbon properties was also studied. For this purpose, the nitrogen adsorption isotherms at 77K and Fourier transform-infrared (FT-IR) spectra analyses were performed. Moreover, iodine number, decolorizing power and adsorption properties of carbon in relation to phenol were studied. Analysis of the results revealed that after WG-12 carbon pre-washing its BET surface increased a little, the pH value of the carbon water extract decreased from 11.0 to 9.4, decolorizing power remained at the same level, and the iodine number and phenol adsorption rate increased. In preliminary studies of the ozonation-biofiltration process, a model phenol solution with concentration of approximately 10mg/l was applied. During the ozonation process a dose of 1.64 mg O(3)/mg TOC (total organic carbon) was employed and the contact time was 5 min. Four empty bed contact times (EBCTs) in the range of 2.4-24.0 min were used in the biofiltration experiment. The effectiveness of purification was measured by the following parameters: chemical oxygen demand (COD(Mn)), TOC, phenol concentration and UV(254)-absorbance. The parameters were found to decrease with EBCT.

Abdominopelvic washings: A comprehensive review

Directory of Open Access Journals (Sweden)

Erika F Rodriguez

2013-01-01

Full Text Available Intraperitoneal spread may occur with gynecological epithelial neoplasms, as well as with non-gynecological malignancies, which may result in serosal involvement with or without concomitant effusion. Therefore, washings in patients with abdominopelvic tumors represent important specimens for cytologic examination. They are primarily utilized for staging ovarian cancers, although their role has decreased in staging of endometrial and cervical carcinoma. Abdominopelvic washings can be positive in a variety of pathologic conditions, including benign conditions, borderline neoplastic tumors, locally invasive tumors, or distant metastases. In a subset of cases, washings can be diagnostically challenging due to the presence of co-existing benign cells (e.g., mesothelial hyperplasia, endosalpingiosis, or endometriosis, lesions in which there is only minimal atypia (e.g., serous borderline tumors or scant atypical cells, and the rarity of specific tumor types (e.g., mesothelioma. Ancillary studies including immunocytochemistry and fluorescence in situ hybridization may be required in difficult cases to resolve the diagnosis. This article provides a comprehensive and contemporary review of abdominopelvic washings in the evaluation of gynecologic and non-gynecologic tumors, including primary peritoneal and mesothelial entities.

Flow parameter determination in pneumatic dilute phase flow applications; Foerderparameterbestimmung in pneumatischen Duennstrom-Transportanwendungen

Energy Technology Data Exchange (ETDEWEB)

Fuchs, A.; Zangl, H.; Brasseur, G. [Technische Univ. Graz (Austria). Inst. fuer Elektrische Messtechnik und Messsignalverarbeitung

2007-07-01

This paper investigates possible approaches towards the development of a flowmeter that allows the determination of the material velocity and the material concentration in pneumatically conveyed bulk solids. These two flow parameters yield the mass flow of material through the conveyor pipe. Measurement methods and sensor principles that satisfy requirements for the flowmeter have been realized as prototype-sensors and were tested in practical dilute phase conveying applications. In particular, the development and the application of optical principles, of a sensor based on spatial filtering, and a capacitive cross-correlation sensor are addressed in the present work. (orig.)

Soil washing

International Nuclear Information System (INIS)

Neuman, R.S.; Diel, B.N.; Halpern, Y.

1992-01-01

Disposal of soils or sludges contaminated with organic and inorganic compounds is a major problem for environmental remedial activities, hazardous waste generators, and the disposal industry. This paper reports that many of these wastes can be effectively treated utilizing soil washing technology. CWM has been developing soil washing technology over the past few years, with extensive work being conducted on the bench scale. These studies have demonstrated consistently high removal efficiencies (95-99%) for a wide variety of PCB and petroleum hydrocarbon contaminated waste. Recently, a comprehensive study examining the removal of both organic and inorganic contraminants from two different types of surrogate soil matrices was completed. In addition to establishing the range of contaminants that can be removed from soil, a method for surfactant/water separation was evaluated. For example, using a thermal phase separation method, approximately 90% of the surfactant could be recovered from the water

Study on cross-flow ultrafiltration for the radioactive liquid waste treatment

International Nuclear Information System (INIS)

Jung, K. H.; Jo, E. S.; Lee, D. G.; Lee, G. W.; Jung, K. J.

2000-01-01

The effect of the UF membranes on permeate flux was investigated in the ultrafiltration of dodecane (0.1v%) / water emulsion and dodecane-SDS-water emulsion in view of the treatment of radioactive oily emulsion liquid waste in the future. For variety of membranes, experiments in cross-flow modes have been performed at various pressure and different cross-flow velocities. Permeate flux decreased with the time and reached a constant steady-state value. Steady-state flux was found to be dependent by the hydrodynamic conditions but independent by the pressure. Flux decrease and rates of permeate flow resistance change have been analysed using a formulation of the equations illustrating the method of resistance mechanism recognition

Influence of flow direction in the performance of anaerobic filters - doi: 10.4025/actascitechnol.v34i2.10353

Directory of Open Access Journals (Sweden)

Ronaldo Fia

2012-03-01

Full Text Available This work aimed to evaluate the performance of similar anaerobic filters operating with opposite wastewater flows, and compare mathematical models that describe the kinetics of organic matter degradation in both. Two pilot-scale filters were fed with domestic effluent – one filter worked as upflow (UAF and the other as downflow (DAF. Experimental COD data obtained from samples taken along the length of the filters were used to fit the first-order mathematical model, the model proposed by Leduy and Zajic (1973 and the model proposed by Brasil et al. (2007. The first model showed overestimated reaction constant (k values when compared to those obtained using the other models. The models proposed by Brasil et al. (2007 and Leduy and Zajic (1973 presented the highest coefficients of determination (R2. The average removal efficiencies of total COD were equal to 68 and 79% for UAF and DAF, respectively. The results revealed no significant differences between the two filters with regard to the variables applied.

Implicit LES using adaptive filtering

Science.gov (United States)

Sun, Guangrui; Domaradzki, Julian A.

2018-04-01

In implicit large eddy simulations (ILES) numerical dissipation prevents buildup of small scale energy in a manner similar to the explicit subgrid scale (SGS) models. If spectral methods are used the numerical dissipation is negligible but it can be introduced by applying a low-pass filter in the physical space, resulting in an effective ILES. In the present work we provide a comprehensive analysis of the numerical dissipation produced by different filtering operations in a turbulent channel flow simulated using a non-dissipative, pseudo-spectral Navier-Stokes solver. The amount of numerical dissipation imparted by filtering can be easily adjusted by changing how often a filter is applied. We show that when the additional numerical dissipation is close to the subgrid-scale (SGS) dissipation of an explicit LES the overall accuracy of ILES is also comparable, indicating that periodic filtering can replace explicit SGS models. A new method is proposed, which does not require any prior knowledge of a flow, to determine the filtering period adaptively. Once an optimal filtering period is found, the accuracy of ILES is significantly improved at low implementation complexity and computational cost. The method is general, performing well for different Reynolds numbers, grid resolutions, and filter shapes.

Countercurrent soil washing system for remediation of viscous hydrocarbons, heavy metals, radionuclides

International Nuclear Information System (INIS)

Kuhlman, M.I.; Karlsson, M.K.; Downie, C.A.

1995-01-01

Drying augers and multicell DAF tanks are excellent machines in which to countercurrently wash soil and remove hazardous hydrocarbons, metals or radionuclides. An auger works well because it preferentially moves soil along one side of its trough. Thus, when enough high pressure and temperature water jets are placed along that path, contaminants can be melted, or dissolved and scoured from the soil. Contaminants and fines flow down the opposite side of the auger and out for extraction in a series of flotation tanks. Countercurrent washing of the silt results when soil settles in tanks through rising water and air bubbles then is pumped through cyclones placed above the next DAF tank of the series. LNAPLs, DNAPLs, or metallic contaminants made hydrophobic by chemicals in the system are removed at the overflow of the cyclones or by flotation in the tanks. The overflow from the cyclones and DAF tanks flows into the previous tank of the series. Examples of contaminants remediated include; arsenic, cadmium, lead and mercury, Naturally Occurring Radioactive Materials (NORM), uranium, solid oils, polyaromatic hydrocarbons in creosote and coal tars, and polychlorinated hydrocarbons

Pulsed-plasma gas-discharge inactivation of microbial pathogens in chilled poultry wash water.

Science.gov (United States)

Rowan, N J; Espie, S; Harrower, J; Anderson, J G; Marsili, L; MacGregor, S J

2007-12-01

A pulsed-plasma gas-discharge (PPGD) system was developed for the novel decontamination of chilled poultry wash water. Treatment of poultry wash water in the plasma generation chamber for up to 24 s at 4 degrees C reduced Escherichia coli NCTC 9001, Campylobacter jejuni ATCC 33560, Campylobacter coli ATCC 33559, Listeria monocytogenes NCTC 9863, Salmonella enterica serovar Enteritidis ATCC 4931, and S. enterica serovar Typhimurium ATCC 14028 populations to non-detectable levels ( or = 3 log CFU/ml) in recalcitrant B. cereus NCTC 11145 endospore numbers within 30 s, the level of endospore reduction was dependent on the nature of the sparged gas used in the plasma treatments. Scanning electron microscopy revealed that significant damage occurred at the cellular level in PPGD-treated test organisms. This electrotechnology delivers energy in intense ultrashort bursts, generating products such as ozone, UV light, acoustic and shock waves, and pulsed electric fields that have multiple bactericidal properties. This technology offers an exciting complementary or alternative approach for treating raw poultry wash water and for preventing cross-contamination in processing environments.

Fluidelastic vibration of cylinder arrays in axial and cross flow--state of the art

International Nuclear Information System (INIS)

Paidoussis, M.P.

1981-01-01

A critical assessment of the state of the art for flow-induced vibrations of cylinder arrays in cross and axial flow is presented. An historical review highlights the contributions which advanced understanding of the flow-induced vibration phenomena involved and/or predictive ability. In the case of axial-flow-induced vibration, the absence of separated flow regions has contributed towards the development of analytical predictive tools. The designer may predict the onset of fluidelastic instabilities, which generally occur at very high flow velocities, with greater confidence. In contrast, in the case of cross-flow-induced vibration, the complexity of the flow has encouraged more heuristic approaches to be adopted. The state of the art in this case is discussed with the aid of a new classification of the flow-induced vibration phenomena involved, to unify and clarify the contradictory claims facing the designer. It is concluded that, although the physical understanding of cross-flow-induced vibration phenomena is not good, useful design guidelines do exist. These are capable of predicting vibration characteristics to within a factor of 2 to 10. A comprehensive bibliography is included. 115 refs

Hydrodynamics of microbial filter feeding.

Science.gov (United States)

Nielsen, Lasse Tor; Asadzadeh, Seyed Saeed; Dölger, Julia; Walther, Jens H; Kiørboe, Thomas; Andersen, Anders

2017-08-29

Microbial filter feeders are an important group of grazers, significant to the microbial loop, aquatic food webs, and biogeochemical cycling. Our understanding of microbial filter feeding is poor, and, importantly, it is unknown what force microbial filter feeders must generate to process adequate amounts of water. Also, the trade-off in the filter spacing remains unexplored, despite its simple formulation: A filter too coarse will allow suitably sized prey to pass unintercepted, whereas a filter too fine will cause strong flow resistance. We quantify the feeding flow of the filter-feeding choanoflagellate Diaphanoeca grandis using particle tracking, and demonstrate that the current understanding of microbial filter feeding is inconsistent with computational fluid dynamics (CFD) and analytical estimates. Both approaches underestimate observed filtration rates by more than an order of magnitude; the beating flagellum is simply unable to draw enough water through the fine filter. We find similar discrepancies for other choanoflagellate species, highlighting an apparent paradox. Our observations motivate us to suggest a radically different filtration mechanism that requires a flagellar vane (sheet), something notoriously difficult to visualize but sporadically observed in the related choanocytes (sponges). A CFD model with a flagellar vane correctly predicts the filtration rate of D. grandis , and using a simple model we can account for the filtration rates of other microbial filter feeders. We finally predict how optimum filter mesh size increases with cell size in microbial filter feeders, a prediction that accords very well with observations. We expect our results to be of significance for small-scale biophysics and trait-based ecological modeling.

Filters in nuclear facilities

International Nuclear Information System (INIS)

Berg, K.H.; Wilhelm, J.G.

1985-01-01

The topics of the nine papers given include the behavior of HEPA filters during exposure to air flows of high humidity as well as of high differential pressure, the development of steel-fiber filters suitable for extreme operating conditions, and the occurrence of various radioactive iodine species in the exhaust air from boiling water reactors. In an introductory presentation the German view of the performance requirements to be met by filters in nuclear facilities as well as the present status of filter quality assurance are discussed. (orig.) [de

Particle image and acoustic Doppler velocimetry analysis of a cross-flow turbine wake

Science.gov (United States)

Strom, Benjamin; Brunton, Steven; Polagye, Brian

2017-11-01

Cross-flow turbines have advantageous properties for converting kinetic energy in wind and water currents to rotational mechanical energy and subsequently electrical power. A thorough understanding of cross-flow turbine wakes aids understanding of rotor flow physics, assists geometric array design, and informs control strategies for individual turbines in arrays. In this work, the wake physics of a scale model cross-flow turbine are investigated experimentally. Three-component velocity measurements are taken downstream of a two-bladed turbine in a recirculating water channel. Time-resolved stereoscopic particle image and acoustic Doppler velocimetry are compared for planes normal to and distributed along the turbine rotational axis. Wake features are described using proper orthogonal decomposition, dynamic mode decomposition, and the finite-time Lyapunov exponent. Consequences for downstream turbine placement are discussed in conjunction with two-turbine array experiments.

Experimental study of fuel bundle vibrations with rods subjected to mixed axial flow and cross-flow provided by a narrow gap (baffle jetting interaction)

International Nuclear Information System (INIS)

Boulanger, P.; Jacques, Y.; Fardeau, P.; Barbier, D.; Rigaudeau, J.

1997-01-01

The Hydraulic Core Laboratory (LHC) performs experimental studies of PWR fuel assembly mechanical behaviour submitted to representative flows in PWR core. Cross-flows prove particularly troublesome by generating on rods, in special cases, vibratory levels high enough to induce early grid to rod fretting. The fluid-structure interaction under mixed axial and cross-flow is also a major topic for analysis. The authors present a test loop devoted to the mixed axial-cross-flow fluid-structure interaction on representative half-scale mockup which is able to simulate, under ambient conditions, any complex flow (direction and flow rates) representative of PWR core flows. Despite its reduced size, the mockup retains the overall structure of a PWR fuel assembly. Rods displacement/velocity and velocity flow field are measured by laser techniques

Filter case for separating out radioactive effluents from gas flows

International Nuclear Information System (INIS)

Jannakos, K.; Zabel, G.

1982-01-01

A remotely operated change of filter in a filter case can be done with an annular or cylindrical filter insert, where the contaminated air side remains separate from the clean air side. A lid is provided which can be divided into two parts, and by which the openings of the filter insert and also in the intermediate floor can be opened or closed using the double lid technique. When closing the filter case lid, the double lid closure is always opened. (DG) [de

The Up-Flow Biological Aerated Filter (UFBAF) process in treating mixed (urban and industrial) sewage. Its performance in a pilot plant; Proceso de biofiltracion Up-Flow Biological Aerated Filter-UFBAF para el tratamiento de aguas residuales mixtas (urbanas e industriales). Rendimientos en planta piloto

Energy Technology Data Exchange (ETDEWEB)

NONE

2003-07-01

The Up-Flow Biological Aerated Filter (UFBAF) process is a variant on the conventional activated sludge process. It is based on a greater sludge density, as the sludge sticks to expanded clay balls of between 3 and 6 mm in diameter. A trial of this process was conducted using a pilot plant whose main components were a bio filter for eliminating organic matter and a single layer filter for eliminating the solids left over from the bio filter. the effluent employed in the trial was waste water that had been pretreated by sieving and primary decanting. The main object of these trials was to determine the capacity and limits of the treatment in eliminating organic matter under overload conditions in order to determine the recovery time required to return to normal operation. (Author) 3 refs.

Feature Subset Selection and Instance Filtering for Cross-project Defect Prediction - Classification and Ranking

Directory of Open Access Journals (Sweden)

Faimison Porto

2016-12-01

Full Text Available The defect prediction models can be a good tool on organizing the project's test resources. The models can be constructed with two main goals: 1 to classify the software parts - defective or not; or 2 to rank the most defective parts in a decreasing order. However, not all companies maintain an appropriate set of historical defect data. In this case, a company can build an appropriate dataset from known external projects - called Cross-project Defect Prediction (CPDP. The CPDP models, however, present low prediction performances due to the heterogeneity of data. Recently, Instance Filtering methods were proposed in order to reduce this heterogeneity by selecting the most similar instances from the training dataset. Originally, the similarity is calculated based on all the available dataset features (or independent variables. We propose that using only the most relevant features on the similarity calculation can result in more accurate filtered datasets and better prediction performances. In this study we extend our previous work. We analyse both prediction goals - Classification and Ranking. We present an empirical evaluation of 41 different methods by associating Instance Filtering methods with Feature Selection methods. We used 36 versions of 11 open source projects on experiments. The results show similar evidences for both prediction goals. First, the defect prediction performance of CPDP models can be improved by associating Feature Selection and Instance Filtering. Second, no evaluated method presented general better performances. Indeed, the most appropriate method can vary according to the characteristics of the project being predicted.

Influence of omni-directional guide vane on the performance of cross-flow rotor for urban wind energy

Science.gov (United States)

Wicaksono, Yoga Arob; Tjahjana, Dominicus Danardono Dwi Prija; Hadi, Syamsul

2018-02-01

Vertical axis wind turbine like cross-flow rotor have some advantage there are, high self-starting torque, low noise, and high stability; so, it can be installed in the urban area to produce electricity. But, the urban area has poor wind condition, so the cross-flow rotor needs a guide vane to increase its performance. The aim of this study is to determine experimentally the effect of Omni-Directional Guide Vane (ODGV) on the performance of a cross-flow wind turbine. Wind tunnel experiment has been carried out for various configurations. The ODGV was placed around the cross-flow rotor in order to increase ambient wind environment of the wind turbine. The maximum power coefficient is obtained as Cpmax = 0.125 at 60° wind direction. It was 21.46% higher compared to cross-flow wind turbine without ODGV. This result showed that the ODGV able to increase the performance of the cross-flow wind turbine.

Dynamic analysis of pedestrian crossing behaviors on traffic flow at unsignalized mid-block crosswalks

Science.gov (United States)

Liu, Gang; He, Jing; Luo, Zhiyong; Yang, Wunian; Zhang, Xiping

2015-05-01

It is important to study the effects of pedestrian crossing behaviors on traffic flow for solving the urban traffic jam problem. Based on the Nagel-Schreckenberg (NaSch) traffic cellular automata (TCA) model, a new one-dimensional TCA model is proposed considering the uncertainty conflict behaviors between pedestrians and vehicles at unsignalized mid-block crosswalks and defining the parallel updating rules of motion states of pedestrians and vehicles. The traffic flow is simulated for different vehicle densities and behavior trigger probabilities. The fundamental diagrams show that no matter what the values of vehicle braking probability, pedestrian acceleration crossing probability, pedestrian backing probability and pedestrian generation probability, the system flow shows the "increasing-saturating-decreasing" trend with the increase of vehicle density; when the vehicle braking probability is lower, it is easy to cause an emergency brake of vehicle and result in great fluctuation of saturated flow; the saturated flow decreases slightly with the increase of the pedestrian acceleration crossing probability; when the pedestrian backing probability lies between 0.4 and 0.6, the saturated flow is unstable, which shows the hesitant behavior of pedestrians when making the decision of backing; the maximum flow is sensitive to the pedestrian generation probability and rapidly decreases with increasing the pedestrian generation probability, the maximum flow is approximately equal to zero when the probability is more than 0.5. The simulations prove that the influence of frequent crossing behavior upon vehicle flow is immense; the vehicle flow decreases and gets into serious congestion state rapidly with the increase of the pedestrian generation probability.

Waste treatment at the Radiochemical Engineering Development Center

International Nuclear Information System (INIS)

Brunson, R.R.; Bond, W.D.; Chattin, F.R.; Collins, R.T.; Sullivan, G.R.; Wiles, R.H.

1997-01-01

At the Radiochemical Engineering Development Center (REDC) irradiated targets are processed for the recovery of valuable radioisotopes, principally transuranium nuclides. A system was recently installed for treating the various liquid alkaline waste streams for removal of excess radioactive contaminants at the REDC. Radionuclides that are removed will be stored as solids and thus the future discharge of radionuclides to liquid low level waste tank storage will be greatly reduced. The treatment system is of modular design and is installed in a hot cell (Cubicle 7) in Building 7920 at the REDC where preliminary testing is in progress. The module incorporates the following: (1) a resorcinol-formaldehyde resin column for Cs removal, (2) a cross flow filtration unit for removal of rare earths and actinides as hydroxide, and (3) a waste solidification unit. Process flowsheets for operation of the module, key features of the module design, and its computer-assisted control system are presented. Good operability of the cross flow filter system is mandatory to the successful treatment of REDC wastes. Results of tests to date on the operation of the filter in its slurry collection mode and its slurry washing mode are presented. These tests include the effects of entrained organic solvent in the waste stream feed to the filter

Peclet number analysis of cross-flow in porous gas diffusion layer of polymer electrolyte membrane fuel cell (PEMFC).

Science.gov (United States)

Suresh, P V; Jayanti, Sreenivas

2016-10-01

Adoption of hydrogen economy by means of using hydrogen fuel cells is one possible solution for energy crisis and climate change issues. Polymer electrolyte membrane (PEM) fuel cell, which is an important type of fuel cells, suffers from the problem of water management. Cross-flow is induced in some flow field designs to enhance the water removal. The presence of cross-flow in the serpentine and interdigitated flow fields makes them more effective in proper distribution of the reactants on the reaction layer and evacuation of water from the reaction layer than diffusion-based conventional parallel flow fields. However, too much of cross-flow leads to flow maldistribution in the channels, higher pressure drop, and membrane dehydration. In this study, an attempt has been made to quantify the amount of cross-flow required for effective distribution of reactants and removal of water in the gas diffusion layer. Unit cells containing two adjacent channels with gas diffusion layer (GDL) and catalyst layer at the bottom have been considered for the parallel, interdigitated, and serpentine flow patterns. Computational fluid dynamics-based simulations are carried out to study the reactant transport in under-the-rib area with cross-flow in the GDL. A new criterion based on the Peclet number is presented as a quantitative measure of cross-flow in the GDL. The study shows that a cross-flow Peclet number of the order of 2 is required for effective removal of water from the GDL. Estimates show that this much of cross-flow is not usually produced in the U-bends of Serpentine flow fields, making these areas prone to flooding.

Cross section of equity returns and assets’ fundamental cash-flow risk

NARCIS (Netherlands)

Galsband, V.

2010-01-01

The decomposition of consumption beta into a component driven by assets' cash-flow news and one related to assets' discount-rate news reveals that macroeconomic risks embodied in cash flows largely account for the cross-sectional dynamics of average stock returns. Empirically, we find that

Respiratory-Induced Haemodynamic Changes: A Contributing Factor to IVC Filter Penetration

International Nuclear Information System (INIS)

Laborda, Alicia; Kuo, William T.; Ioakeim, Ignatios; De Blas, Ignacio; Malvè, Mauro; Lahuerta, Celia; De Gregorio, Miguel A.

2015-01-01

PurposeThe purpose of the study is to evaluate the influence of respiratory-induced vena caval hemodynamic changes on filter migration/penetration.Materials and MethodsAfter placement of either a Gunther Tulip or Celect IVC filter, 101 consecutive patients scheduled for filter retrieval were prospectively enrolled in this study. Pre-retrieval CT scans were used to assess filter complications and to calculate cross-sectional area in three locations: at level of filter strut fixation, 3 cm above and 3 cm below. A 3D finite element simulation was constructed on these data and direct IVC pressure was recorded during filter retrieval. Cross-sectional areas and pressures of the vena cava were measured during neutral breathing and in Valsalva maneuver and identified filter complications were recorded. A statistical analysis of these variables was then performed.ResultsDuring Valsalva maneuvers, a 60 % decrease of the IVC cross-sectional area and a fivefold increase in the IVC pressure were identified (p < 0.001). There was a statistically significant difference in the reduction of the cross-sectional area at the filter strut level (p < 0.001) in patient with filter penetration. Difficulty in filter retrieval was higher in penetrated or tilted filters (p < 0.001; p = 0.005). 3D computational models showed significant IVC deformation around the filter during Valsalva maneuver.ConclusionCaval morphology and hemodynamics are clearly affected by Valsalva maneuvers. A physiological reduction of IVC cross-sectional area is associated with higher risk of filter penetration, despite short dwell times. Physiologic data should be used to improve future filter designs to remain safely implanted over longer dwell times

Respiratory-Induced Haemodynamic Changes: A Contributing Factor to IVC Filter Penetration

Energy Technology Data Exchange (ETDEWEB)

Laborda, Alicia, E-mail: alaborda@unizar.es [Universidad de Zaragoza, Minimally Invasive Techniques Research Group (GITMI) (Spain); Kuo, William T., E-mail: wkuo@stanford.edu [Stanford University Medical Center, Division of Vascular and Interventional Radiology (United States); Ioakeim, Ignatios, E-mail: ignacio.ioakim@hotmail.es [Universidad de Zaragoza, Minimally Invasive Techniques Research Group (GITMI) (Spain); De Blas, Ignacio, E-mail: deblas@unizar.es [Universidad de Zaragoza, Unit of Infectious Diseases and Epidemiology, Department of Animal Pathology (Spain); Malvè, Mauro, E-mail: mauro.malve@unavarra.es [Universidad Pública de Navarra, Department of Mechanical, Energy and Materials Engineering (Spain); Lahuerta, Celia, E-mail: celialahuerta@gmail.com; De Gregorio, Miguel A., E-mail: mgregori@unizar.es [Universidad de Zaragoza, Minimally Invasive Techniques Research Group (GITMI) (Spain)

2015-10-15

PurposeThe purpose of the study is to evaluate the influence of respiratory-induced vena caval hemodynamic changes on filter migration/penetration.Materials and MethodsAfter placement of either a Gunther Tulip or Celect IVC filter, 101 consecutive patients scheduled for filter retrieval were prospectively enrolled in this study. Pre-retrieval CT scans were used to assess filter complications and to calculate cross-sectional area in three locations: at level of filter strut fixation, 3 cm above and 3 cm below. A 3D finite element simulation was constructed on these data and direct IVC pressure was recorded during filter retrieval. Cross-sectional areas and pressures of the vena cava were measured during neutral breathing and in Valsalva maneuver and identified filter complications were recorded. A statistical analysis of these variables was then performed.ResultsDuring Valsalva maneuvers, a 60 % decrease of the IVC cross-sectional area and a fivefold increase in the IVC pressure were identified (p < 0.001). There was a statistically significant difference in the reduction of the cross-sectional area at the filter strut level (p < 0.001) in patient with filter penetration. Difficulty in filter retrieval was higher in penetrated or tilted filters (p < 0.001; p = 0.005). 3D computational models showed significant IVC deformation around the filter during Valsalva maneuver.ConclusionCaval morphology and hemodynamics are clearly affected by Valsalva maneuvers. A physiological reduction of IVC cross-sectional area is associated with higher risk of filter penetration, despite short dwell times. Physiologic data should be used to improve future filter designs to remain safely implanted over longer dwell times.

Potential of activated carbon to recover randomly-methylated-β-cyclodextrin solution from washing water originating from in situ soil flushing.

Science.gov (United States)

Sniegowski, K; Vanhecke, M; D'Huys, P-J; Braeken, L

2014-07-01

Despite the overall high efficacy of cyclodextrins to accelerate the treatment of soil aquifer remediation by in-situ soil flushing, the use in practice remains limited because of the high costs of cyclodextrin and high concentrations needed to significantly reduce the treatment time. The current study tested the potential of activated carbon to treat washing water originating from soil flushing in order to selectively separate hydrocarbon contaminants from washing water containing cyclodextrin and subsequently reuse the cyclodextrin solution for reinfiltration. A high recovery of the cyclodextrin from the washing water would reduce the costs and would make the technique economically feasible for soil remediation. This study aimed to investigate whether cyclodextrin can pass through the activated carbon filter without reducing the cyclodextrin concentration when the contaminated washing water is treated and whether the presence of cyclodextrin negatively affects the purification potential of activated carbon to remove the organic pollutants from the pumped soil water. Lab-scale column experiments showed that with the appropriate activated carbon 100% of cyclodextrin (randomly-methylated-β-cyclodextrin) can be recovered from the washing water and that the effect on the efficiency of activated carbon to remove the hydrocarbon contaminants remains limited. These results show that additional field tests are useful to make in-situ soil flushing with cyclodextrin both a technical and an economical interesting technique. These results might stimulate the application of cyclodextrin in soil treatment technology. Copyright © 2013 Elsevier B.V. All rights reserved.

Geometric optimization of cross-flow heat exchanger based on dynamic controllability

Directory of Open Access Journals (Sweden)

Alotaibi Sorour

2008-01-01

Full Text Available The operation of heat exchangers and other thermal equipments in the face of variable loads is usually controlled by manipulating inlet fluid temperatures or mass flow rates, where the controlled variable is usually one of the output temperatures. The aim of this work is to optimize the geometry of a tube with internal flow of water and an external cross-flow of air, based on its controllability characteristics. Controllability is a useful concept both from theoretical and practical perspective since it tells us if a particular output can be controlled by a particular input. This concept can also provide us with information about the easiest operating condition to control a particular output. A transient model of a tube in cross-flow is developed, where an implicit formulation is used for transient numerical solutions. The aspect ratio of the tube is optimized, subject to volume constraints, based on the optimum operation in terms of controllability. The reported optimized aspect ratio, water mass flow rate and controllability are studied for deferent external properties of the tube.

Detecting wash trade in the financial market

OpenAIRE

Cao, Yi; Li, Yuhua; Coleman, Sonya; Belatreche, Ammar; McGinnity, T. M.

2014-01-01

Wash trade refers to the activities of traders who utilise deliberately designed collusive transactions to increase the trading volumes for creating active market impression. Wash trade can be damaging to the proper functioning and integrity of capital markets. Existing work focuses on collusive clique detections based on certain assumptions of trading behaviours. Effective approaches for analysing and detecting wash trade in a real-life market have yet to be developed. T...

Washing of waste prior to landfilling.

Science.gov (United States)

Cossu, Raffaello; Lai, Tiziana

2012-05-01

The main impact produced by landfills is represented by the release of leachate emissions. Waste washing treatment has been investigated to evaluate its efficiency in reducing the waste leaching fraction prior to landfilling. The results of laboratory-scale washing tests applied to several significant residues from integrated management of solid waste are presented in this study, specifically: non-recyclable plastics from source separation, mechanical-biological treated municipal solid waste and a special waste, automotive shredded residues. Results obtained demonstrate that washing treatment contributes towards combating the environmental impacts of raw wastes. Accordingly, a leachate production model was applied, leading to the consideration that the concentrations of chemical oxygen demand (COD) and total Kjeldahl nitrogen (TKN), parameters of fundamental importance in the characterization of landfill leachate, from a landfill containing washed wastes, are comparable to those that would only be reached between 90 and 220years later in the presence of raw wastes. The findings obtained demonstrated that washing of waste may represent an effective means of reducing the leachable fraction resulting in a consequent decrease in landfill emissions. Further studies on pilot scale are needed to assess the potential for full-scale application of this treatment. Copyright © 2012 Elsevier Ltd. All rights reserved.

Backflushable filter insert

International Nuclear Information System (INIS)

Keith, R.C.; Vandenberg, T.; Randolph, M.C.; Lewis, T.B.; Gillis, P.J. Jr.

1988-01-01

Filter elements are mounted on a tube plate beneath an accumulator chamber whose wall is extended by skirt and flange to form a closure for the top of pressure vessel. The accumulator chamber is annular around a central pipe which serves as the outlet for filtered water passing from the filter elements. The chamber contains filtered compressed air from supply. Periodically the filtration of water is stopped and vessel is drained. Then a valve is opened, allowing the accumulated air to flow from chamber up a pipe and down pipe, pushing the filtered water from pipe back through the filter elements to clean them. The accumulator chamber is so proportioned, relative to the volume of the system communicating therewith during backflushing, that the equilibrium pressure during backflushing cannot exceed the pressure rating of the vessel. However a line monitors the pressure at the top of the vessel, and if it rises too far a bleed valve is automatically opened to depressurise the system. The chamber is intended to replace the lid of an existing vessel to convert a filter using filter aid to one using permanent filter elements. (author)

Virtual analysis of influence of a filter on mould filling

Directory of Open Access Journals (Sweden)

Zhian Xu

2011-11-01

Full Text Available Ceramic filters are used to avoid slag and impurities in foundry applications. When not properly applied, the presence of these filters may have a significant influence on mould filling. 3-D casting simulation has been applied to study the effects of the use of a ceramic filter on the metal flow in a gating system. Instead of using a pressure drop model to represent the behaviour of a fluid metal flow passing through a filter, a real exact filter geometry, which is created by a high resolution CT-scan and a non-destructive imaging technique, in the gating system is applied in the simulation. In this research, nodular cast iron is poured into a block casting. A depressurized gating system is used. After a choke, a filter with different orientations is placed in the system. Mould filling coupled with temperature is simulated. Geometries using different orientations of the filter, and without the filter have been researched. The simulated results show that the filter has no influence on the pouring time of the casting if the choke section is small enough compared to the effective section of the filter. Although the filter has no significant influence on the flow patterns in the block casting itself, the flow patterns in the filter zone are different. When the liquid metal passes a horizontal filter, it will be broken into many small streams and show a shower effect. After the part under the filter is full, the shower effect disappears. When the filter is located at the vertical position, due to the gravity, the shower effect is less. If no filter presents on the system, the liquid metal passes through the filter zone with a high speed and causes surface turbulence.

Cross-Generational Knowledge Flows in Edge Organizations: Research in Progress

National Research Council Canada - National Science Library

Liebowitz, Jay; Ayyavoo, Nirmala; Nguyen, Hang; Simien, James

2007-01-01

.... In order for workforce development and succession planning to be effective in edge organizations, cross-generational knowledge flows are paramount towards achieving an innovative and agile organization...

Genesis Eco Systems, Inc. soil washing process

International Nuclear Information System (INIS)

Cena, R.J.

1994-01-01

The Genesis soil washing system is an integrated system of modular design allowing for maximum material handling capabilities, with optimized use of space for site mobility. The Surfactant Activated Bio-enhanced Remediation Equipment-Generation 1 (SABRE-1, Patent Applied For) modification was developed specifically for removing petroleum byproducts from contaminated soils. Scientifically formulated surfactants, introduced by high pressure spray nozzles, displace the contaminant from the surface of the soil particles into the process solution. Once the contaminant is dispersed into the liquid fraction of the process, it is either mechanically removed, chemically oxidized, or biologically oxidized. The contaminated process water is pumped through the Genesis Biosep (Patent Applied For) filtration system where the fines portion is flocculated, and the contaminant-rich liquid portion is combined with an activated mixture of nutrients and carefully selected bacteria to decompose the hydrocarbon fraction. The treated soil and dewatered fines are transferred to a bermed stockpile where bioremediation continues during drying. The process water is reclaimed, filtered, and recycled within the system

The effects of material loading and flow rate on the disinfection of pathogenic microorganisms using cation resin-silver nanoparticle filter system

Science.gov (United States)

Mpenyana-Monyatsi, L.; Mthombeni, N. H.; Onyango, M. S.; Momba, M. N. B.

2017-08-01

Waterborne diseases have a negative impact on public health in instances where the available drinking water is of a poor quality. Decentralised systems are needed to provide safe drinking water to rural communities. Therefore, the present study aimed to develop and investigate the point-of-use (POU) water treatment filter packed with resin-coated silver nanoparticles. The filter performance was evaluated by investigating the effects of various bed masses (10 g, 15 g, 20 g) and flow rates (2 mL/min, 5 mL/min, 10 mL/min) by means of breakthrough curves for the removal efficiency of presumptive Escherichia coli, Shigella dysenteriae, Salmonella typhimurium and Vibrio cholerae from spiked groundwater samples. The results revealed that, as the bed mass increases the breakthrough time also increases with regards to all targeted microorganisms. However, when the flow rate increases the breakthrough time decreased. These tests demonstrated that resin-coated silver nanoparticle can be an effective material in removing all targeted microorganisms at 100% removal efficiency before breakthrough points are achieved. Moreover the filter system demonstrated that it is capable of producing 15 L/day of treated water at an operating condition of 10 mL/min flow rate and 15 g bed mass, which is sufficient to provide for seven individuals in the household if they consume 2 L/person/day for drinking purpose. Therefore, the bed mass of the filter system should be increased in order for it to produce sufficient water that will conform to the daily needs of an individual.

Shielded regeneration heating element for a particulate filter

Science.gov (United States)

Gonze, Eugene V [Pinckney, MI; Ament, Frank [Troy, MI

2011-01-04

An exhaust system includes a particulate filter (PF) that is disposed downstream from an engine. The PF filters particulates within an exhaust from the engine. A heating element heats particulate matter in the PF. A catalyst substrate or a flow converter is disposed upstream from said heating element. The catalyst substrate oxidizes the exhaust prior to reception by the heating element. The flow converter converts turbulent exhaust flow to laminar exhaust flow prior to reception by the heating element.

Cross-flow turbines: physical and numerical model studies towards improved array simulations

Science.gov (United States)

Wosnik, M.; Bachant, P.

2015-12-01

Cross-flow, or vertical-axis turbines, show potential in marine hydrokinetic (MHK) and wind energy applications. As turbine designs mature, the research focus is shifting from individual devices towards improving turbine array layouts for maximizing overall power output, i.e., minimizing wake interference for axial-flow turbines, or taking advantage of constructive wake interaction for cross-flow turbines. Numerical simulations are generally better suited to explore the turbine array design parameter space, as physical model studies of large arrays at large model scale would be expensive. However, since the computing power available today is not sufficient to conduct simulations of the flow in and around large arrays of turbines with fully resolved turbine geometries, the turbines' interaction with the energy resource needs to be parameterized, or modeled. Most models in use today, e.g. actuator disk, are not able to predict the unique wake structure generated by cross-flow turbines. Experiments were carried out using a high-resolution turbine test bed in a large cross-section tow tank, designed to achieve sufficiently high Reynolds numbers for the results to be Reynolds number independent with respect to turbine performance and wake statistics, such that they can be reliably extrapolated to full scale and used for model validation. To improve parameterization in array simulations, an actuator line model (ALM) was developed to provide a computationally feasible method for simulating full turbine arrays inside Navier--Stokes models. The ALM predicts turbine loading with the blade element method combined with sub-models for dynamic stall and flow curvature. The open-source software is written as an extension library for the OpenFOAM CFD package, which allows the ALM body force to be applied to their standard RANS and LES solvers. Turbine forcing is also applied to volume of fluid (VOF) models, e.g., for predicting free surface effects on submerged MHK devices. An

THEORETICAL AND EXPERIMENTAL ANALYSIS OF A CROSS-FLOW HEAT EXCHANGER

Directory of Open Access Journals (Sweden)

R. Tuğrul OĞULATA

1996-03-01

Full Text Available In this study, cross-flow plate type heat exchanger has been investigated because of its effective use in waste heat recovery systems. For this purpose, a heat regain system has been investigated and manufactured in laboratory conditions. Manufactured heat exchanger has been tested with an applicable experimental set up and temperatures, velocity of the air and the pressure losses occuring in the system have been measured and the efficiency of the system has been determined. The irreversibility of heat exchanger has been taken into consideration while the design of heat exchanger is being performed. So minimum entropy generation number has been analysied with respect to second law of thermodynamics in cross-flow heat exchanger. The minimum entropy generation number depends on parameters called optimum flow path length, dimensionless mass velocity and dimensionless heat transfer area. Variations of entropy generation number with these parameters have been analysied and introduced their graphics with their comments.

Experimental study of filter cake formation on different filter media

International Nuclear Information System (INIS)

Saleem, M.

2009-01-01

Removal of particulate matter from gases generated in the process industry is important for product recovery as well as emission control. Dynamics of filtration plant depend on operating conditions. The models, that predict filter plant behaviour, involve empirical resistance parameters which are usually derived from limited experimental data and are characteristics of the filter media and filter cake (dust deposited on filter medium). Filter cake characteristics are affected by the nature of filter media, process parameters and mode of filter regeneration. Removal of dust particles from air is studied in a pilot scale jet pulsed bag filter facility resembling closely to the industrial filters. Limestone dust and ambient air are used in this study with two widely different filter media. All important parameters like pressure drop, gas flow rate, dust settling, are recorded continuously at 1s interval. The data is processed for estimation of the resistance parameters. The pressure drop rise on test filter media is compared. Results reveal that the surface of filter media has an influence on pressure drop rise (concave pressure drop rise). Similar effect is produced by partially jet pulsed filter surface. Filter behaviour is also simulated using estimated parameters and a simplified model and compared with the experimental results. Distribution of cake area load is therefore an important aspect of jet pulse cleaned bag filter modeling. Mean specific cake resistance remains nearly constant on thoroughly jet pulse cleaned membrane coated filter bags. However, the trend can not be confirmed without independent cake height and density measurements. Thus the results reveal the importance of independent measurements of cake resistance. (author)

PERFORMANCE OF A SURFACE FLOW CONSTRUCTED WETLAND SYSTEM USED TO TREAT SECONDARY EFFLUENT AND FILTER BACKWASH WATER

Directory of Open Access Journals (Sweden)

Juan Antonio Vidales-Contreras

2011-05-01

The performance of a surface flow wetland system used to treat activated sludge effluent and filter backwash water from a tertiary treatment facility was evaluated. Samples were collected before and after vegetation removal from the system which consists of two densely vegetated settling basins (0.35 ha, an artificial stream, and a 3-ha surface flow wetland. Bulrush (Scripus spp. and cattail (Typha domingensis were the dominant plant species. The average inflow of chlorinated secondary effluent during the first two months of the actual study was 1.9  m3 min-1 while the inflow for backwash water treatment ranged from 0.21 to 0.42 m3 min-1. The system was able to reduce TSS and BOD5 to tertiary effluent standards; however, monitoring of chloride concentrations revealed that wetland evapotranspiration is probably enriching pollutant concentrations in the wetland outflow. Coliphage removal from the filter backwash was 97 and 35% during 1999 and 2000, respectively. However, when secondary effluent entered the system, coliphage removal averaged 65%. After vegetation removal, pH and coliphage density increased significantly (p

Gas-liquid mass transfer in a cross-flow hollow fiber module : Analytical model and experimental validation

NARCIS (Netherlands)

Dindore, V. Y.; Versteeg, G. F.

2005-01-01

The cross-flow operation of hollow fiber membrane contactors offers many advantages and is preferred over the parallel-flow contactors for gas-liquid mass transfer operations. However, the analysis of such a cross-flow membrane gas-liquid contactor is complicated due to the change in concentrations

Bacterial reduction by cell salvage washing and leukocyte depletion filtration.

Science.gov (United States)

Waters, Jonathan H; Tuohy, Marion J; Hobson, Donna F; Procop, Gary

2003-09-01

Blood conservation techniques are being increasingly used because of the increased cost and lack of availability of allogeneic blood. Cell salvage offers great blood savings opportunities but is thought to be contraindicated in a number of areas (e.g., blood contaminated with bacteria). Several outcome studies have suggested the safety of this technique in trauma and colorectal surgery, but many practitioners are still hesitant to apply cell salvage in the face of frank bacterial contamination. This study was undertaken to assess the efficacy of bacterial removal when cell salvage was combined with leukocyte depletion filtration. Expired packed erythrocytes were obtained and inoculated with a fixed amount of a stock bacteria (Escherichia coli American Type Culture Collections [ATCC] 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 29213, or Bacteroides fragilis ATCC 25285) in amounts ranging from 2,000 to 4,000 colony forming units/ml. The blood was processed via a cell salvage machine. The washed blood was then filtered using a leukocyte reduction filter. The results for blood taken during each step of processing were compared using a repeated-measures design. Fifteen units of blood were contaminated with each of the stock bacteria. From the prewash sample to the postfiltration sample, 99.0%, 99.6%, 100%, and 97.6% of E. coli, S. aureus, P. aeruginosa, and B. fragilis were removed, respectively. Significant but not complete removal of contaminating bacteria was seen. An increased level of patient safety may be added to cell salvage by including a leukocyte depletion filter when salvaging blood that might be grossly contaminated with bacteria.

High performance wash-free magnetic bioassays through microfluidically enhanced particle specificity.

Science.gov (United States)

Bechstein, Daniel J B; Lee, Jung-Rok; Ooi, Chin Chun; Gani, Adi W; Kim, Kyunglok; Wilson, Robert J; Wang, Shan X

2015-06-30

Magnetic biosensors have emerged as a sensitive and versatile platform for high performance medical diagnostics. These magnetic biosensors require well-tailored magnetic particles as detection probes, which need to give rise to a large and specific biological signal while showing very low nonspecific binding. This is especially important in wash-free bioassay protocols, which do not require removal of particles before measurement, often a necessity in point of care diagnostics. Here we show that magnetic interactions between magnetic particles and magnetized sensors dramatically impact particle transport and magnetic adhesion to the sensor surfaces. We investigate the dynamics of magnetic particles' biomolecular binding and magnetic adhesion to the sensor surface using microfluidic experiments. We elucidate how flow forces can inhibit magnetic adhesion, greatly diminishing or even eliminating nonspecific signals in wash-free magnetic bioassays, and enhancing signal to noise ratios by several orders of magnitude. Our method is useful for selecting and optimizing magnetic particles for a wide range of magnetic sensor platforms.

Debris filtering efficiency and its effect on long term cooling capability

International Nuclear Information System (INIS)

Jung, Min-Su; Kim, Kyu-Tae

2013-01-01

Highlights: • Debris filtering efficiencies for two debris filter designs used in PWRs are provided. • Various debris used in the tests are selected to simulate actual debris found in PWRs. • Debris filter efficiency is explained by flow-hole size and grid strap height. • The effect of debris filters on flow blockage during LTC after a LOCA is described. -- Abstract: A cutting-edge debris-filter designs, Protective Grid (P-grid) and Guardian Grid (G-grid) attached to the upper part of bottom nozzle, have been employed for the PWRs in Korea since 2000s to protect the fuel from debris-induced fuel failures. The debris-filter efficiency of the P-grid and G-grid designs is improved by relatively smaller flow areas formed by the grid straps and dimples. The debris-filter efficiency of the P-grid design is further improved by the relatively smaller flow-hole bottom nozzle. The debris-filter flow tests employing eighteen debris types showed that the debris-filter efficiencies of the P-grid and G-grid designs are 91 and 96%, respectively, while that of the SYS80 fuel design having only the standard flow-hole bottom nozzle is 26%. The slightly better debris-filter efficiency of the G-grid design against the P-grid design may be explained by relatively smaller flow areas at the G-grid dimple region as well as by the relatively longer solid end plug and the higher G-grid strap. The P-grid design may capture circular shapes of debris larger than 3.44 mm in diameter at the flow holes formed by the P-grid dimples, whereas the G-grid design may capture circular shapes of debris larger than 2.54 mm in diameter at the flow holes formed by the G-grid dimples. The aforementioned difference in the debris-filter efficiency between the P-grid and G-grid designs may be predicted by the solid modeling technique generating three-dimensional flow paths. Using the minimum flow-hole areas generated by the P-grid and G-grid designs, on the other hand, the effect of debris injected from

Numerical simulation of a cross flow Marine Hydrokinetic turbine.

Science.gov (United States)

Hall, Taylor; Aliseda, Alberto

2011-11-01

In the search for alternative sources of energy, the kinetic energy of water currents in oceans, rivers and estuaries is being explored as predictable and environmentally benign. We are investigating the flow past a cross flow turbine in which a helical blade under hydrodynamic forces turns around a shaft perpendicular to the free stream. This type of turbine, while very different from the classical horizontal axis turbine commonly used in the wind energy field, presents advantages for stacking in very narrow constricted channels where the water currents are consistently high and therefore turbine installation may be economically feasible. We use a model of a helical four-bladed turbine in cross flow to investigate the efficiency of the energy capture and the dynamics of the turbulent wake. Scale model experiments in a flume are used to validate the numerical results on a stationary configuration as an initial step towards creating an accurate numerical model of the turbine. The simulation of the rotating turbine provides a full perspective on the effect of angular position on flow detachment and vortex shedding from the blade, as well as on the fluctuations of the shaft torque produced (a problematic feature of this type of turbine). The results are analyzed in terms of hydrodynamic optimization of the blade and its structural loading. Supported by DOE through the Northwest National Marine Renewable Energy Center.

Calibration and use of filter test facility orifice plates

Science.gov (United States)

Fain, D. E.; Selby, T. W.

1984-07-01

There are three official DOE filter test facilities. These test facilities are used by the DOE, and others, to test nuclear grade HEPA filters to provide Quality Assurance that the filters meet the required specifications. The filters are tested for both filter efficiency and pressure drop. In the test equipment, standard orifice plates are used to set the specified flow rates for the tests. There has existed a need to calibrate the orifice plates from the three facilities with a common calibration source to assure that the facilities have comparable tests. A project has been undertaken to calibrate these orifice plates. In addition to reporting the results of the calibrations of the orifice plates, the means for using the calibration results will be discussed. A comparison of the orifice discharge coefficients for the orifice plates used at the seven facilities will be given. The pros and cons for the use of mass flow or volume flow rates for testing will be discussed. It is recommended that volume flow rates be used as a more practical and comparable means of testing filters. The rationale for this recommendation will be discussed.

33 CFR 157.124 - COW tank washing machines.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false COW tank washing machines. 157... OIL IN BULK Crude Oil Washing (COW) System on Tank Vessels Design, Equipment, and Installation § 157.124 COW tank washing machines. (a) COW machines must be permanently mounted in each cargo tank. (b...

Hand washing in operating room: a procedural comparison

Directory of Open Access Journals (Sweden)

Alessia Stilo

2016-09-01

Full Text Available BACKGROUND Hand washing has been considered a measure of personal hygiene for centuries and it is known that an improper hand hygiene by healthcare workers is responsible for about 40% of nosocomial infections. Therefore, surgical hand preparation is a critical element for healthcare safety in order to reduce microbial contamination of  surgical wound in case of non detected break of the gloves. The aim of our study is to evaluate the efficacy three antiseptics: Povi-iodine scrub; EPG (Ethanol, Hydrogen Peroxide, Glycerol, recommended by WHO, and common marseille soap type in a liquid formulation. METHODS It was designed a randomized, double-blind, single-center study conducted in the University Hospital of Messina, from January to June 2013. We asked operators to put the fingertips of their right hand (if not left-handed for one minute on the PCA medium, before washing with the three types of antiseptics, and after washing and drying. Drying was made using sterile gauzes or disposable wipes. Then, we measured the number of colony forming units per mL (CFU/mL and calculated the percentage of microbial load reduction. RESULTS 211 samples have been considered for statistical analysis: in 42 samples, in fact, initial microbial load was lower than after washing. Washing with EPG reduced CFU/ml from  a mean of 38,9 to 4,1 (86,5% reduction, washing with povi-iodine scrub from 59,55 to 12,9 (75,9% reduction and washing with Marseille soap from 47,26 to 12,7 (64,3% reduction. CONCLUSIONS Our study shows that washing with EPG has superior efficacy in CFU reduction. Antiseptic hand washing, however, cannot be considered the only measure to reduce infections: the anomaly of some results (initial microbial load lower than after washing  demonstrates that drying is an essential phase in the presurgical preparation. Therefore, hand hygiene must be part of a more complex strategy of surveillance and control of nosocomial infections

Washing technology development for gravel contaminated with uranium

Energy Technology Data Exchange (ETDEWEB)

Park, Uk Ryang; Kim, Gye Nam; Kim, Seung Soo; Kim, Wan Suk; Moon, Jai Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2013-10-15

The soil washing method has a short decontamination time and is economical. In addition, methods including phytoremediation, solidification/stabilization and bioremediation exist. Phytoremediation and bioremediation are economical, but have low remedial efficiency. In addition, bioremediation causes washing wastewater because it requires a washing process for the separation of microorganisms from the soils. In addition, solidification/stabilization is a commonly used methods, but eventually increases the volume of wastes. As mentioned above, many researches involved in the decontamination of radioactively contaminated soils have been actively processed. On the other hand, researches for decontaminating radioactively contaminated gravels are not being currently processed. In this study, we performed basic experiments using decontamination methods to decontaminate radioactively contaminated gravel. First, we measured the concentration of uranium in gravel included in uranium-contaminated soils and performed a washing experiment to monitor the tendency of uranium removal. In addition, when managing gravel with a low uranium-decontamination rate, we tried to satisfy the radioactivity concentration criteria for self-disposal in the wastes (0.4Bq/g or less) by performing a washing experiment after only a physical crushing process. We performed washing experiments to satisfy the radioactivity concentration criteria for self-disposal (0.4 Bq/g or less) in gravel included in radioactively contaminated soil. We performed washing experiments for gravel whose initial average concentration of uranium was 1.3Bq/g. In addition, the average concentration of uranium was 0.8Bq/g. Too increase the decontamination rate, we crushed the gravel with a jaw crusher and performed the washing experiments. The results were similar to the results without crushing. In addition, it was determined that the smaller the size of the gravel particles, the more efficient the uranium decontamination

Apparatus for washing out halogens

Energy Technology Data Exchange (ETDEWEB)

Pier, M; Hahn, J; Kroenig, W

1941-03-26

An apparatus is described for washing out of halogens and the like or liquid halogen compounds from the products, which are formed on pressure hydrogenation or splitting of carbon-containing material in the presence of halogens or halogen compounds, consisting of a washing apparatus installed between the reaction vessel and the hot separator, which is inclined in relatively small space for steam regulation and contains, with the steam, arranged baffles, especially spirals.

Experimental investigation of air side heat transfer and fluid flow performances of multi-port serpentine cross-flow mesochannel heat exchanger

International Nuclear Information System (INIS)

Siddiqui, Faisal A.; Dasgupta, Engr Sarbadaman; Fartaj, Amir

2012-01-01

Highlights: ► Air side heat transfer and flow characteristics of mesochannel cross-flow heat exchanger are studied experimentally. ► Hot ethylene glycol–water mixture (50:50) at constant mass flow rate is used against varying air flow. ► Air side heat transfer and fluid flow key parameters such as Nusselt number, Colburn factor, friction factor are obtained. ► General correlations are proposed for air side heat transfer and fluid flow parameters. - Abstract: Air side force convective heat transfer and flow characteristics of cross-flow mesochannel heat exchanger are investigated experimentally. A series of experiments representing 36 different operating conditions have been conducted on a finned mesochannel heat exchanger through the fully automated dynamic single-phase experimental facility which is capable of handling a wide variety of working fluids in air-to-liquid cross-flow orientation. The mesochannel heat exchanger is made of 15 aluminum slabs with arrays of wavy fins between slabs; 68 one millimeter circular diameter port located at each slab, and the air side frontal area of 304-mm × 304-mm. The ethylene glycol–water mixture as the working fluid in the liquid side was forced to flow through mesochannels maintaining constant inlet temperature and flow rate at 74 °C and 0.0345 kg/s respectively whereas the inlet flowing air into the arrays of wavy fins was changed at four different temperature levels from 28 °C to 43 °C. Frontal air velocity was altered in nine steps from 3 m/s to 11 m/s at each temperature level corresponding range of Reynolds number 752 a a ) and Colburn factor (j a ) were found higher in comparison with other studies.

Numerical Investigation of Cross Flow Phenomena in a Tight-Lattice Rod Bundle Using Advanced Interface Tracking Method

Science.gov (United States)

Zhang, Weizhong; Yoshida, Hiroyuki; Ose, Yasuo; Ohnuki, Akira; Akimoto, Hajime; Hotta, Akitoshi; Fujimura, Ken

In relation to the design of an innovative FLexible-fuel-cycle Water Reactor (FLWR), investigation of thermal-hydraulic performance in tight-lattice rod bundles of the FLWR is being carried out at Japan Atomic Energy Agency (JAEA). The FLWR core adopts a tight triangular lattice arrangement with about 1 mm gap clearance between adjacent fuel rods. In view of importance of accurate prediction of cross flow between subchannels in the evaluation of the boiling transition (BT) in the FLWR core, this study presents a statistical evaluation of numerical simulation results obtained by a detailed two-phase flow simulation code, TPFIT, which employs an advanced interface tracking method. In order to clarify mechanisms of cross flow in such tight lattice rod bundles, the TPFIT is applied to simulate water-steam two-phase flow in two modeled subchannels. Attention is focused on instantaneous fluctuation characteristics of cross flow. With the calculation of correlation coefficients between differential pressure and gas/liquid mixing coefficients, time scales of cross flow are evaluated, and effects of mixing section length, flow pattern and gap spacing on correlation coefficients are investigated. Differences in mechanism between gas and liquid cross flows are pointed out.

Theoretical and experimental study of a cross-flow induced-draft cooling tower

Directory of Open Access Journals (Sweden)

Abo Elazm Mahmoud Mohamed

2009-01-01

Full Text Available The main objective of this study is to find a proper solution for the cross-flow water cooling tower problem, also to find an empirical correlation's controlling heat and mass transfer coefficients as functions of inlet parameters to the tower. This is achieved by constructing an experimental rig and a computer program. The computer simulation solves the problem numerically. The apparatus used in this study comprises a cross-flow cooling tower. From the results obtained, the 'characteristic curve' of cross-flow cooling towers was constructed. This curve is very helpful for designers in order to find the actual value of the number of transfer units, if the values of inlet water temperature or inlet air wet bulb temperature are changed. Also an empirical correlation was conducted to obtain the required number of transfer units of the tower in hot water operation. Another correlation was found to obtain the effectiveness in the wet bulb operation.

Spatial filtring and thermocouple spatial filter

International Nuclear Information System (INIS)

Han Bing; Tong Yunxian

1989-12-01

The design and study on thermocouple spatial filter have been conducted for the flow measurement of integrated reactor coolant. The fundamental principle of spatial filtring, mathematical descriptions and analyses of thermocouple spatial filter are given

Cold or hot wash: Technological choices, cultural change, and their impact on clothes-washing energy use in China

International Nuclear Information System (INIS)

Lin, Jiang; Iyer, Maithili

2007-01-01

Usage pattern of clothes washing (and clothes washers) are strongly related to local cultural practices. Such practices have led to the development of distinctive clothes-washing technologies in the US, Europe, and Japan. In emerging markets such as China, several types of technologies often co-exist. Some use less energy but more water (the impeller type), and some use more energy but less water (the horizontal axis type). The competition between different technologies is thought to lead to better consumer choices. However, it could also lead to changes in clothes-washing habits-from cold to hot wash, and therefore to much higher energy use. This paper examines the standard development process in China to illustrate that adoption of foreign technologies and technical standards, if not carefully calibrated to the local cultural practices, could have unintended consequences for energy use and environment

Process and device for regulating an electromagnetic filter

International Nuclear Information System (INIS)

Dolle, Lucien.

1980-01-01

Process for regulating the operation of an electromagnetic filter and, in particular, for keeping the efficiency of the filter at a sufficiently high level irrespective of the degree of filter clogging, fluid flow rate and temperature of the fluid. The filter includes an envelope containing a filling that can be magnetized by a coil activated by a d.c. supply arranged around the envelope. The regulating process includes the following stages: - activating the coil by a current of lower intensity than that of the saturation current of the filling, - determining the pressure drop of the filter, fluid flow rate and fluid temperature, - increasing the intensity of the current activating the coil when the efficiency of the filter corresponding to the measured values drops below a given level [fr

Neutron Beam Filters

International Nuclear Information System (INIS)

Adib, M.

2011-01-01

The purpose of filters is to transmit neutrons with selected energy, while remove unwanted ones from the incident neutron beam. This reduces the background, and the number of spurious. The types of commonly used now-a-day neutron filters and their properties are discussed in the present work. There are three major types of neutron filters. The first type is filter of selective thermal neutron. It transmits the main reflected neutrons from a crystal monochromate, while reject the higher order contaminations accompanying the main one. Beams coming from the moderator always contain unwanted radiation like fast neutrons and gamma-rays which contribute to experimental background and to the biological hazard potential. Such filter type is called filter of whole thermal neutron spectrum. The third filter type is it transmits neutrons with energies in the resonance energy range (En . 1 KeV). The main idea of such neutron filter technique is the use of large quantities of a certain material which have the deep interference minima in its total neutron cross-section. By transmitting reactor neutrons through bulk layer of such material, one can obtain the quasimonochromatic neutron lines instead of white reactor spectrum.

Eulerian Time-Domain Filtering for Spatial LES

Science.gov (United States)

Pruett, C. David

1997-01-01

Eulerian time-domain filtering seems to be appropriate for LES (large eddy simulation) of flows whose large coherent structures convect approximately at a common characteristic velocity; e.g., mixing layers, jets, and wakes. For these flows, we develop an approach to LES based on an explicit second-order digital Butterworth filter, which is applied in,the time domain in an Eulerian context. The approach is validated through a priori and a posteriori analyses of the simulated flow of a heated, subsonic, axisymmetric jet.

Analysis of a Multi-Venturi filter for the venting of the primary container of a nuclear reactor

International Nuclear Information System (INIS)

Reyes G, A. A.; Sainz M, E.; Ortiz V, J.

2017-09-01

Since the Chernobyl nuclear accident, European nuclear power plants have opted to install filters in the containment vent pipes, whose function is to help mitigate the consequences of a severe accident, by means of the controlled depressurization of the containment passively through of a containment filtering vent system. These systems are designed to relieve the internal pressure of containment by deliberately opening pressure relief devices, either a valve or rupture disk during a severe accident and being channeled to the filtering unit. In this work, the hydraulic response of a liquid gas washing filtration system is evaluated, since this information is necessary to estimate the effect of the increase of the containment pressure on the venting capacity of the vent pipes. Through CFD simulation, using the programs with open source license CaeLinux-2014 and OpenFoam, the hydrodynamic characteristics of the Multi-Venturi system were obtained for the washing of the gases coming from the containment, which could be included in the general model of the vent pipe. Representative models of the venturi tubes of each concentric sector that are part of the washing system were generated and by parametric calculations the average mass expense established by each venturi was estimated, according to its dimensions and depth to which is located inside the tank. In the same way, the pressure and mass expense required to activate each concentric sector was calculated according to the pressure and mass load from the containment, in order to estimate the maximum expenditure that is established through the filter. The velocity profiles and the characteristic pressure at which each sector operates were also calculated, as well as the local and global discharge pressure drop. (Author)

Sludge pretreatment chemistry evaluation: Enhanced sludge washing separation factors

International Nuclear Information System (INIS)

Colton, N.G.

1995-03-01

This report presents the work conducted in Fiscal Year 1994 by the Sludge Pretreatment Chemistry Evaluation Subtask for the Tank Waste Remediation System (TWRS) Tank Waste Treatment Science Task. The main purpose of this task, is to provide the technical basis and scientific understanding to support TWRS baseline decisions and actions, such as the development of an enhanced sludge washing process to reduce the volume of waste that will require high-level waste (HLW) vitrification. One objective within the Sludge Pretreatment Chemistry Evaluation Subtask was to establish wash factors for various SST (single-shell tank) sludges. First, analytical data were compiled from existing tank waste characterization reports. These data were summarized on tank-specific worksheets that provided a uniform format for reviewing and comparing data, as well as the means to verify whether the data set for each tank was complete. Worksheets were completed for 27 SST wastes. The analytical water wash data provided tank-specific information about the fraction of each component that dissolves with water, i.e., an estimate of tank-specific wash factors for evaluating tank-by-tank processing. These wash data were then used collectively to evaluate some of the wash factors that are assumed for the overall SST waste inventory; specifically, wash factors for elements that would be found primarily in sludges. The final step in this study was to incorporate the characterization and wash factor data into a spreadsheet that provides insight into the effect of enhanced sludge washing on individual tank sludges as well as for groups of sludges that may be representative of different waste types. Spreadsheet results include the estimated mass and percentage of each element that would be removed with washing and leaching. Furthermore, estimated compositions are given of the final wash and leach streams and residual solids, in terms of both concentration and dry weight percent

Estimated ground-water recharge from streamflow in Fortymile Wash near Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Savard, C.S.

1998-01-01

The two purposes of this report are to qualitatively document ground-water recharge from stream-flow in Fortymile Wash during the period 1969--95 from previously unpublished ground-water levels in boreholes in Fortymile Canyon during 1982--91 and 1995, and to quantitatively estimate the long-term ground-water recharge rate from streamflow in Fortymile Wash for four reaches of Fortymile Wash (Fortymile Canyon, upper Jackass Flats, lower Jackass Flats, and Amargosa Desert). The long-term groundwater recharge rate was estimated from estimates of the volume of water available for infiltration, the volume of infiltration losses from streamflow, the ground-water recharge volume from infiltration losses, and an analysis of the different periods of data availability. The volume of water available for infiltration and ground-water recharge in the four reaches was estimated from known streamflow in ephemeral Fortymile Wash, which was measured at several gaging station locations. The volume of infiltration losses from streamflow for the four reaches was estimated from a streamflow volume loss factor applied to the estimated streamflows. the ground-water recharge volume was estimated from a linear relation between infiltration loss volume and ground-water recharge volume for each of the four reaches. Ground-water recharge rates were estimated for three different periods of data availability (1969--95, 1983--95, and 1992--95) and a long-term ground-water recharge rate estimated for each of the four reaches

Estimated ground-water recharge from streamflow in Fortymile Wash near Yucca Mountain, Nevada