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Sample records for annular centrifugal contactors

  1. Design Attributes and Scale Up Testing of Annular Centrifugal Contactors

    Energy Technology Data Exchange (ETDEWEB)

    David H. Meikrantz; Jack D. Law

    2005-04-01

    Annular centrifugal contactors are being used for rapid yet efficient liquid- liquid processing in numerous industrial and government applications. Commercialization of this technology began eleven years ago and now units with throughputs ranging from 0.25 to 700 liters per minute are readily available. Separation, washing, and extraction processes all benefit from the use of this relatively new commercial tool. Processing advantages of this technology include: low in-process volume per stage, rapid mixing and separation in a single unit, connection-in-series for multi-stage use, and a wide operating range of input flow rates and phase ratios without adjustment. Recent design enhancements have been added to simplify maintenance, improve inspection ability, and provide increased reliability. Cartridge-style bearing and mechanical rotary seal assemblies that can include liquid-leak sensors are employed to enhance remote operations, minimize maintenance downtime, prevent equipment damage, and extend service life. Clean-in-place capability eliminates the need for disassembly, facilitates the use of contactors for feed clarification, and can be automated for continuous operation. In nuclear fuel cycle studies, aqueous based separations are being developed that efficiently partition uranium, actinides, and fission products via liquid-liquid solvent extraction. Thus, annular centrifugal contactors are destined to play a significant role in the design of such new processes. Laboratory scale studies using mini-contactors have demonstrated feasibility for many such separation processes but validation at an engineering scale is needed to support actual process design.

  2. Liquid–Liquid Mixing Studies in Annular Centrifugal Contactors Comparing Stationary Mixing Vane Options

    Energy Technology Data Exchange (ETDEWEB)

    Wardle, Kent E.

    2015-11-10

    Comparative studies of multiphase operation of annular centrifugal contactors showing the impact of housing stationary mixing vane configuration. A number of experimental results for several different mixing vane options are reported with selected measurements in a lab-scale 5 cm contactor and 12.5 cm engineering-scale unit. Fewer straight vanes give greater mixingzone hold-up compared to curved vanes. Quantitative comparison of droplet size distribution also showed a significant decrease in mean diameter for four straight vanes versus eight curved vanes. This set of measurements gives a compelling case for careful consideration of mixing vane geometry when evaluating hydraulic operation and extraction process efficiency of annular centrifugal contactors.

  3. THE TESTING OF COMMERCIALLY AVAILABLE ENGINEERING AND PLANT SCALE ANNULAR CENTRIFUGAL CONTACTORS FOR THE PROCESSING OF SPENT NUCLEAR FUEL

    Energy Technology Data Exchange (ETDEWEB)

    Jack D. Law; David Meikrantz; Troy Garn; Nick Mann; Scott Herbst

    2006-10-01

    Annular centrifugal contactors are being evaluated for process scale solvent extraction operations in support of United State Advanced Fuel Cycle Initiative goals. These contactors have the potential for high stage efficiency if properly employed and optimized for the application. Commercially available centrifugal contactors are being tested at the Idaho National Laboratory to support this program. Hydraulic performance and mass transfer efficiency have been measured for portions of an advanced nuclear fuel cycle using 5-cm diameter annular centrifugal contactors. Advanced features, including low mix sleeves and clean-in-place rotors, have also been evaluated in 5-cm and 12.5-cm contactors.

  4. Experimental Measurements of Drop Size Distributions in 30 mm Diameter Annular Centrifugal Contactor with 30% TBP-Nitric Acid Biphasic System

    Directory of Open Access Journals (Sweden)

    Shekhar Kumar

    2013-01-01

    Full Text Available For design and development of liquid-liquid extraction systems, it is essential to have an accurate estimation of hydrodynamic and mass transfer characteristics of the employed contactor. In the present study, experimental evaluations consisted primarily of determining the maximum solution throughput that could be processed without cross-phase contamination at a given rotor speed, O/A flow ratio, and organic-aqueous solution pair in a 30 mm bowl diameter centrifugal contactor. In addition, analysis included experimental drop size determinations as well as holdup determination. The experimental drop size distributions are expected to be helpful for modeling work.

  5. CFD Simulation of Annular Centrifugal Extractors

    Directory of Open Access Journals (Sweden)

    S. Vedantam

    2012-01-01

    Full Text Available Annular centrifugal extractors (ACE, also called annular centrifugal contactors offer several advantages over the other conventional process equipment such as low hold-up, high process throughput, low residence time, low solvent inventory and high turn down ratio. The equipment provides a very high value of mass transfer coefficient and interfacial area in the annular zone because of the high level of power consumption per unit volume and separation inside the rotor due to the high g of centrifugal field. For the development of rational and reliable design procedures, it is important to understand the flow patterns in the mixer and settler zones. Computational Fluid Dynamics (CFD has played a major role in the constant evolution and improvements of this device. During the past thirty years, a large number of investigators have undertaken CFD simulations. All these publications have been carefully and critically analyzed and a coherent picture of the present status has been presented in this review paper. Initially, review of the single phase studies in the annular region has been presented, followed by the separator region. In continuation, the two-phase CFD simulations involving liquid-liquid and gas-liquid flow in the annular as well as separator regions have been reviewed. Suggestions have been made for the future work for bridging the existing knowledge gaps. In particular, emphasis has been given to the application of CFD simulations for the design of this equipment.

  6. Centrifugal contactor operations for UREX process flowsheet. An update

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Candido [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2014-08-01

    The uranium extraction (UREX) process separates uranium, technetium, and a fraction of the iodine from the other components of the irradiated fuel in nitric acid solution. In May 2012, the time, material, and footprint requirements for treatment of 260 L batches of a solution containing 130 g-U/L were evaluated for two commercial annular centrifugal contactors from CINC Industries. These calculated values were based on the expected volume and concentration of fuel arising from treatment of a single target solution vessel (TSV). The general conclusions of that report were that a CINC V-2 contactor would occupy a footprint of 3.2 m 2 (0.25 m x 15 m) if each stage required twice the nominal footprint of an individual stage, and approximately 1,131 minutes or nearly 19 hours is required to process all of the feed solution. A CINC V-5 would require approximately 9.9 m 2 (0.4 m x 25 m) of floor space but would require only 182 minutes or ~ 3 hours to process the spent target solution. Subsequent comparison with the Modular Caustic Side Solvent Extraction Unit (MCU) at Savannah River Site (SRS) in October 2013 suggested that a more compact arrangement is feasible, and the linear dimension for the CINC V-5 may be reduced to about 8 m; a comparable reduction for the CINC V-2 yields a length of 5 m. That report also described an intermediate-scale (10 cm) contactor design developed by Argonne in the early 1980s that would better align with the SHINE operations as they stood in May 2012. In this report, we revisit the previous evaluation of contactor operations after discussions with CINC Industries and analysis of the SHINE process flow diagrams for the cleanup of the TSV, which were not available at the time of the first assessment.

  7. The use of a centrifugal contactor for component concentration by solvent extraction

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, R.A.; Wygmans, D.G.; McElwee, M.J.; Wasserman, M.O.; Vandegrift, G.F.

    1992-07-01

    Theoretical and experimental work was undertaken to explore the use of the Argonne design centrifugal contactor as a concentrating device for metal ions in solutions such as transuranic-containing waste streams and contaminated groundwater. First, the theoretical basis for operating the contactor as a concentrator was developed. Then, the ability of the contactor to act as a concentrating device was experimentally demonstrated with neodymium over a wide range of organic-to-aqueous (O/A) flow ratios (0.01 to 33). These data were also used to derive a correlation for the effect of O/A flow ratio on extraction efficiency.

  8. Centrifugal contactor with liquid mixing and flow control vanes and method of mixing liquids of different phases

    Science.gov (United States)

    Jubin, Robert T.; Randolph, John D.

    1991-01-01

    The invention is directed to a centrifugal contactor for solvent extraction systems. The centrifugal contactor is provided with an annular vertically oriented mixing chamber between the rotor housing and the rotor for mixing process liquids such as the aqueous and organic phases of the solvent extraction process used for nuclear fuel reprocessing. A set of stationary helically disposed vanes carried by the housing is in the lower region of the mixing chamber at a location below the process-liquid inlets for the purpose of urging the liquids in an upward direction toward the inlets and enhancing the mixing of the liquids and mass transfer between the liquids. The upper region of the mixing vessel above the inlets for the process liquids is also provided with a set helically disposed vanes carried by the housing for urging the process liquids in a downward direction when the liquid flow rates through the inlets are relatively high and the liquids contact the vane set in the upper region. The use of these opposing vane sets in the mixing zone maintains the liquid in the mixing zone at suitable levels.

  9. Novel highly integrated biodiesel production technology in a centrifugal contactor separator device

    NARCIS (Netherlands)

    Kraai, G. N.; Schuur, B.; van Zwol, F.; van de Bovenkamp, H. H.; Heeres, H. J.

    2009-01-01

    The base catalyzed production of biodiesel (FAME) from sunflower oil and methanol in a continuous centrifugal contactor separator (CCS) with integrated reaction and phase separation was studied. The effect of catalyst loading (sodium methoxide), temperature, rotational frequency and flow rates of th

  10. Biodiesel synthesis from Jatropha curcas L. oil and ethanol in a continuous centrifugal contactor separator

    NARCIS (Netherlands)

    Abduh, Muhammad Yusuf; van Ulden, Wouter; Kalpoe, Vijay; van de Bovenkamp, Hendrik H.; Manurung, Robert; Heeres, Hero J.

    2013-01-01

    The synthesis of fatty acid ethyl esters (FAEE) from Jatropha curcas L. oil was studied in a batch reactor and a continuous centrifugal contactor separator (CCCS) using sodium ethoxide as the catalyst. The effect of relevant process variables like rotational speed, temperature, catalyst concentratio

  11. Synthesis and refining of sunflower biodiesel in a cascade of continuous centrifugal contactor separators

    NARCIS (Netherlands)

    Bin Abu Ghazali, Yusuf; van Ulden, Wouter; van de Bovenkamp, Hendrik; Teddy, T; Picchioni, Francesco; Manurung, Robert; Heeres, Hero J.

    2015-01-01

    The synthesis of fatty acid methyl esters (FAME) from sunflower oil and methanol was studied in a continuous centrifugal contactor separator (CCCS) using sodium methoxide as the catalyst. The effect of relevant process variables like oil and methanol flow rate, rotational speed and catalyst concentr

  12. Centrifugal pyrocontactor

    Science.gov (United States)

    Chow, Lorac S.; Leonard, Ralph A.

    1993-01-01

    A method for mixing and separating immiscible liquid salts and liquid metals in a centrifugal contractor. The method includes introducing the liquids into an annular mixing zone and intensely mixing the liquids using vertical vanes attached to a rotor cooperating with vertical baffles, a horizontal baffle, and bottom vanes attached to the contactor housing. The liquids enter the contactor in the range of 700-800 degrees Celsius. The liquids are separated in the rotor into a dense phase and a light phase which are discharged from the contactor.

  13. Towards an optimized flow-sheet for a SANEX demonstration process using centrifugal contactors

    Energy Technology Data Exchange (ETDEWEB)

    Magnusson, D. [European Commission, Joint Research Center, Karlsruhe (Germany). Inst. for Transuranium Elements; Chalmers Univ. of Technology, Gothenburg (Sweden). Nuclear Chemistry, Dept. of Chemical and Biological Engineering; Christiansen, B.; Glatz, J.P.; Malmbeck, R.; Serrano-Purroy, D. [European Commission, Joint Research Center, Karlsruhe (Germany). Inst. for Transuranium Elements; Modolo, G. [Forschungszentrum Juelich GmbH (Germany). Inst. for Energy Research, Safety Research and Reactor Technology; Sorel, C. [Commissariat a l' Energie Atomique Valrho (CEA), DRCP/SCPS, Bagnols-sur-Ceze (France)

    2009-07-01

    The design of an efficient process flow-sheet requires accurate extraction data for the experimental set-up used. Often this data is provided as equilibrium data. Due to the small hold-up volume compared to the flow rate in centrifugal contactors the time for extraction is often too short to reach equilibrium D-ratios. In this work single stage kinetics experiments have been carried out to investigate the D-ratio dependence of the flow rate and to compare this with equilibrium batch experiments for a SANEX system based on CyMe{sub 4}-BTBP. The first centrifuge experiment was run with spiked solutions while in the second a genuine actinide/lanthanide fraction from a TODGA process was used. Three different flow rates were tested with each set-up. The results show that even with low flow rates, only around 9% of the equilibrium D-ratio (Am) was reached for the extraction in the spiked test and around 16% in the hot test (the difference is due to the size of the centrifuges). In the hot test the lanthanide scrubbing was inefficient whereas in the stripping both the actinides and the lanthanides showed good results. Based on these results improvements of the suggested flow-sheet is discussed. (orig.)

  14. Centrifugal contactor modified for end stage operation in a multistage system

    Science.gov (United States)

    Jubin, Robert T.

    1990-01-01

    A cascade formed of a plurality of centrifugal contactors useful for countercurrent solvent extraction processes such as utilizable for the reprocessing of nuclear reactor fuels is modified to permit operation in the event one or both end stages of the cascade become inoperative. Weir assemblies are connected to each of the two end stages by suitable conduits for separating liquids discharged from an inoperative end stage based upon the weight of the liquid phases uses in the solvent extraction process. The weir assembly at one end stage is constructed to separate and discharge the heaviest liquid phase while the weir assembly at the other end stage is constructed to separate and discharge the lightest liquid phase. These weir assemblies function to keep the liquid discharge from an inoperative end stages on the same weight phase a would occur from an operating end stage.

  15. Mass Transfer Testing of a 12.5-cm Rotor Centrifugal Contactor

    Energy Technology Data Exchange (ETDEWEB)

    D. H. Meikrantz; T. G. Garn; J. D. Law; N. R. Mann; T. A. Todd

    2008-09-01

    TRUEX mass transfer tests were performed using a single stage commercially available 12.5 cm centrifugal contactor and stable cerium (Ce) and europium (Eu). Test conditions included throughputs ranging from 2.5 to 15 Lpm and rotor speeds of 1750 and 2250 rpm. Ce and Eu extraction forward distribution coefficients ranged from 13 to 19. The first and second stage strip back distributions were 0.5 to 1.4 and .002 to .004, respectively, throughout the dynamic test conditions studied. Visual carryover of aqueous entrainment in all organic phase samples was estimated at < 0.1 % and organic carryover into all aqueous phase samples was about ten times less. Mass transfer efficiencies of = 98 % for both Ce and Eu in the extraction section were obtained over the entire range of test conditions. The first strip stage mass transfer efficiencies ranged from 75 to 93% trending higher with increasing throughput. Second stage mass transfer was greater than 99% in all cases. Increasing the rotor speed from 1750 to 2250 rpm had no significant effect on efficiency for all throughputs tested.

  16. Hydraulic forces caused by annular pressure seals in centrifugal pumps

    Science.gov (United States)

    Iino, T.; Kaneko, H.

    1980-01-01

    The hydraulic forces caused by annular pressure seals were investigated. The measured inlet and exit loss coefficients of the flow through the seals were much smaller than the conventional values. The results indicate that the damping coefficient and the inertia coefficient of the fluid film in the seal are not affected much by the rotational speed or the eccentricity of the rotor, though the stiffness coefficient seemed to be influenced by the eccentricity.

  17. Experimental and modelling studies on continuous synthesis and refining of biodiesel in a dedicated bench scale unit using centrifugal contactor separator technology

    NARCIS (Netherlands)

    Abduh, Muhammad Yusuf; Martinez, Alberto Fernandez; Kloekhorst, Arjan; Manurung, Robert; Heeres, Hero J.

    2016-01-01

    Continuous synthesis and refining of biodiesel (FAME) using a laboratory scale bench scale unit was explored. The unit consists of three major parts: (i) a continuous centrifugal contactor separator (CCCS) to perform the reaction between sunflower oil and methanol; (ii) a washing unit for the crude

  18. Hydrodynamic features of centrifugal contactor separators; experimental studies on liquid hold-up, residence time distribution, phase behavior and drop size distributions

    NARCIS (Netherlands)

    Schuur, B.; Kraai, G.N.; Winkelman, J.G.N.; Heeres, H.

    2012-01-01

    The liquid hold-up, residence time distributions (RTD), drop size distributions and continuous/dispersed phase for a typical centrifugal contactor separator (CCS) of the type CINC V02 were determined experimentally for various L-L systems. The hold-up ratio of the different solvents was mainly a fun

  19. Hydrodynamic features of centrifugal contactor separators : Experimental studies on liquid hold-up, residence time distribution, phase behavior and drop size distributions

    NARCIS (Netherlands)

    Schuur, Boelo; Kraai, Gerard N.; Winkelman, Jozef G. M.; Heeres, Hero J.

    2012-01-01

    The liquid hold-up, residence time distributions (RTD), drop size distributions and continuous/dispersed phase for a typical centrifugal contactor separator (CCS) of the type CINC V02 were determined experimentally for various L-L systems. The hold-up ratio of the different solvents was mainly a fun

  20. Fluid-Structure Interaction Analysis on Turbulent Annular Seals of Centrifugal Pumps during Transient Process

    Directory of Open Access Journals (Sweden)

    Qinglei Jiang

    2011-01-01

    Full Text Available The current paper studies the influence of annular seal flow on the transient response of centrifugal pump rotors during the start-up period. A single rotor system and three states of annular seal flow were modeled. These models were solved using numerical integration and finite difference methods. A fluid-structure interaction method was developed. In each time step one of the three annular seal models was chosen to simulate the annular seal flow according to the state of rotor systems. The objective was to obtain a transient response of rotor systems under the influence of fluid-induced forces generated by annular seal flow. This method overcomes some shortcomings of the traditional FSI method by improving the data transfer process between two domains. Calculated results were in good agreement with the experimental results. The annular seal was shown to have a supportive effect on rotor systems. Furthermore, decreasing the seal clearance would enhance this supportive effect. In the transient process, vibration amplitude and critical speed largely changed when the acceleration of the rotor system increased.

  1. A New Approach to Designing the S-Shaped Annular Duct for Industrial Centrifugal Compressor

    Directory of Open Access Journals (Sweden)

    Ivan Yurko

    2014-01-01

    Full Text Available The authors propose an analytical method for designing the inlet annular duct for an industrial centrifugal compressor using high-order Bezier curves. Using the design of experiments (DOE theory, the three-level full factorial design was developed for determination of influence of the dimensionless geometric parameters on the output criteria. Numerical research was carried out for determination of pressure loss coefficients and velocity swirl angles using the software system ANSYS CFX. Optimal values of the slope for a wide range of geometric parameters, allowing minimizing losses in the duct, have been found. The study has used modern computational fluid dynamics techniques to develop a generalized technique for future development of efficient variable inlet guide vane systems. Recommendations for design of the s-shaped annular duct for industrial centrifugal compressor have been given.

  2. Fractional reactive extraction for symmetrical separation of 4-nitro-D,L-phenylalanine in centrifugal contactor separators: experiments and modeling.

    Science.gov (United States)

    Tang, Kewen; Wen, Ping; Zhang, Panliang; Huang, Yan

    2015-01-01

    The enantioselective liquid-liquid extraction of 4-nitro-D,L-phenylalanine (D,L-Nphy) using PdCl2 {(s)-BINAP} as extractant in dichloroethane was studied experimentally in a countercurrent cascade of 10 centrifugal contactor separators (CCSs) at 5°C, involving flow ratio, extractant concentration, and Cl(-) concentration. The steady-state enantiomeric excess (ee) in both stream exits was 90.86% at a 93.29% yield. The predicted value was modeled using an equilibrium stage approach. The correlation between model and experiment was satisfactory. The model was applied to optimize the production of both enantiomers in >97% ee and >99% ee. 14 stages and 16 stages are required for 97% ee and 99% ee for both enantiomers, respectively.

  3. Recent advances of annular centrifugal extractor for hot test of nuclear waste partitioning process

    Institute of Scientific and Technical Information of China (English)

    HeXiang-Ming; YanYu-Shun; 等

    1998-01-01

    Advances are being made in the design of the annular centrifugal extractor fornuclear fuel reprocessing extraction process studies.The extractors have been built and tested.Twelve stages of this extractor and 50 stages are used toimplement the TRPO process for the cleanup ofcommercial and defense nuclear waste liquids,respectively.Following advances are available:(1) simple way of assembly and disassembly between rotor part and housing part of extractor,ease of manipulator operation;(2)automatic sampling from housing of extractor in hot cell;(3) compact multi-stage housing system;(4) easy interstage link;(5) computer data acquisition and monitoring system of speed.

  4. Demonstration of a SANEX Process in Centrifugal Contactors using the CyMe{sub 4}-BTBP Molecule on a Genuine Fuel Solution

    Energy Technology Data Exchange (ETDEWEB)

    Magnusson, D.; Christiansen, B.; Glatz, J.P.; Malmbeck, R.; Serrano-Purroy, D. [European Commiss, Joint Res Ctr, Inst Transuranium Elements, D-76125 Karlsruhe, (Germany); Foreman, M.R.S. [Univ Reading, Dept Chem, Reading RG6 6AD, Berks, (United Kingdom); Geist, A. [Forschungszentrum Karlsruhe, Inst Nukl Entsorgung, D-76021 Karlsruhe, (Germany); Modolo, G. [Forschungszentrum Julich, Inst Energy Res Safety Res and Reactor Technol, D-52425 Julich, (Germany); Sorel, C. [Commissariat Energie Atom Valrho, CEA, DRCP SCPS, F-30207 Bagnols Sur Ceze, (France)

    2009-07-01

    Efficient recovery of minor actinides from a genuine spent fuel solution has been successfully demonstrated by the CyMe{sub 4}-BTBP/DMDOHEMA extractant mixture dissolved in octanol. The continuous countercurrent process, in which actinides(III) were separated from lanthanides(III), was carried out in laboratory centrifugal contactors using an optimized flow-sheet involving a total of 16 stages. The process was divided into 9 stages for extraction from a 2 M nitric acid feed solution, 3 stages for lanthanide scrubbing, and 4 stages for actinide back-extraction. Excellent feed decontamination factors for Am (7000) and Cm (1000) were obtained and the recoveries of these elements were higher than 99.9%. More than 99.9% of the lanthanides were directed to the raffinate except Gd for which 0.32% was recovered in the product. (authors)

  5. Experimental and Model Studies on Continuous Separation of 2-Phenylpropionic Acid Enantiomers by Enantioselective Liquid-Liquid Extraction in Centrifugal Contactor Separators.

    Science.gov (United States)

    Feng, Xiaofeng; Tang, Kewen; Zhang, Pangliang; Yin, Shuangfeng

    2016-03-01

    Multistage enantioselective liquid-liquid extraction (ELLE) of 2-phenylpropionic acid (2-PPA) enantiomers using hydroxypropyl-β-cyclodextrin (HP-β-CD) as extractant was studied experimentally in a counter-current cascade of centrifugal contactor separators (CCSs). Performance of the process was evaluated by purity (enantiomeric excess, ee) and yield (Y). A multistage equilibrium model was established on the basis of single-stage model for chiral extraction of 2-PPA enantiomers and the law of mass conservation. A series of experiments on the extract phase/washing phase ratio (W/O ratio), extractant concentration, the pH value of aqueous phase, and the number of stages was conducted to verify the multistage equilibrium model. It was found that model predictions were in good agreement with the experimental results. The model was applied to predict and optimize the symmetrical separation of 2-PPA enantiomers. The optimal conditions for symmetric separation involves a W/O ratio of 0.6, pH of 2.5, and HP-β-CD concentration of 0.1 mol L(-1) at a temperature of 278 K, where eeeq (equal enantiomeric excess) can reach up to 37% and Yeq (equal yield) to 69%. By simulation and optimization, the minimum number of stages was evaluated at 98 and 106 for eeeq > 95% and eeeq > 97%.

  6. FLUID CONTACTOR APPARATUS

    Science.gov (United States)

    Spence, R.; Streeton, R.J.W.

    1956-04-17

    The fluid contactor apparatus comprises a cylindrical column mounted co- axially and adapted to rotate within a cylindrical vessel, for the purpose of extracting a solute from am aqueous solution by means of an organic solvent. The column is particularly designed to control the vortex pattern so as to reduce the height of the vortices while, at the same time, the width of the annular radius in the radial direction between the vessel and column is less than half the radius of the column. A plurality of thin annular fins are spaced apart along the rotor approximately twice the radial dimension of the column such that two contrarotating substantially circular vortices are contained within each pair of fins as the column is rotated.

  7. Membrane contactor applications

    NARCIS (Netherlands)

    Klaassen, R.; Feron, P.H.M.; Jansen, A.

    2008-01-01

    In a membrane contactor the membrane separation is completely integrated with an extraction or absorption operation in order to exploit the benefits of both technologies fully. Membrane contactor applications that have been developed can be found in both water and gas treatment. Several recently dev

  8. Research Advances on flow field of annular centrifugal extraction%环隙式离心萃取器流场研究进展

    Institute of Scientific and Technical Information of China (English)

    潘九海; 甘仁武; 张艳红; 白志山

    2012-01-01

    围绕工业应用,人们在环隙流场稳定性、水力学特性等方面做了大量研究,而对环隙的流场流动机理、泰勒涡流场结构等方面的研究较少,随着线性和非线性理论、计算流体力学和流动可视化技术的飞速发展,对环隙流场流动机理、涡流场的结构进行详细直观描述有了可能,主要从环隙流场可视化、环隙流场数值模拟2个方面对该研究进行了系统的分析总结,并为将来的研究工作提出了几点意见.%Around the industrial application of annular centrifugal extractor ( ACE) , the flow instabilities, hydrodynamic characteristics and mass transfer performance of ACE has been extensively studied. But relatively scanty information is available on the detailed quantitative flow pattern and the structure of vortex. With the rapid development of linear and nonlinear theory, Computational Fluid Dynamics and flow visualization technology, more and more information was provided for the research of flow regime and vortex cell- The published literature has been critically analysed and presented in this paper,some specific recommendations have been made for future work.

  9. Contactor/filter improvements

    Science.gov (United States)

    Stelman, David

    1989-01-01

    A contactor/filter arrangement for removing particulate contaminants from a gaseous stream includes a housing having a substantially vertically oriented granular material retention member with upstream and downstream faces, a substantially vertically oriented microporous gas filter element, wherein the retention member and the filter element are spaced apart to provide a zone for the passage of granular material therethrough. The housing further includes a gas inlet means, a gas outlet means, and means for moving a body of granular material through the zone. A gaseous stream containing particulate contaminants passes through the gas inlet means as well as through the upstream face of the granular material retention member, passing through the retention member, the body of granular material, the microporous gas filter element, exiting out of the gas outlet means. Disposed on the upstream face of the filter element is a cover screen which isolates the filter element from contact with the moving granular bed and collects a portion of the particulates so as to form a dust cake having openings small enough to exclude the granular material, yet large enough to receive the dust particles. In one embodiment, the granular material is comprised of prous alumina impregnated with CuO, with the cover screen cleaned by the action of the moving granular material as well as by backflow pressure pulses.

  10. Electric vehicle drive train with contactor protection

    Science.gov (United States)

    Konrad, Charles E.; Benson, Ralph A.

    1994-01-01

    A drive train for an electric vehicle includes a traction battery, a power drive circuit, a main contactor for connecting and disconnecting the traction battery and the power drive circuit, a voltage detector across contacts of the main contactor, and a controller for controlling the main contactor to prevent movement of its contacts to the closed position when the voltage across the contacts exceeds a predetermined threshold, to thereby protect the contacts of the contactor. The power drive circuit includes an electric traction motor and a DC-to-AC inverter with a capacitive input filter. The controller also inhibits the power drive circuit from driving the motor and thereby discharging the input capacitor if the contacts are inadvertently opened during motoring. A precharging contactor is controlled to charge the input filter capacitor prior to closing the main contactor to further protect the contacts of the main contactor.

  11. ENGINEERING BULLETIN: ROTATING BIOLOGICAL CONTACTORS

    Science.gov (United States)

    Rotating biological contactors employ aerobic fixed-film treatment to degrade either organic and/or nitrogenous (ammonia-nitrogen) constituents present in aqueous waste streams. ixed-film systems provide a surface to which the biomass can adhere. Treatment is achieved as the wast...

  12. CENTRIFUGE APPARATUS

    Science.gov (United States)

    Skarstrom, C.; Urey, H.C.; Cohen, K.

    1960-08-01

    A high-speed centrifuge for the separation of gaseous isotopes is designed comprising a centrifugal pump mounted on the outlet of a centrifuge bowl and arranged to pump the heavy and light fractions out of the centrifuge bowl in two separate streams.

  13. Research on the displacement control method of asynchronous modular contactor

    Science.gov (United States)

    He, Gong; Ming, Zong

    2017-01-01

    Ac contactor is a kind of low voltage electrical appliances with large usage and wide application. Because of the frequent operation, contactor life must be long enough to ensure the reliable operation of power system. The electrical life of the contactor, as the key to affect the service life of the contactor, is mainly affected by the arc developed in the breaking and closing course. This paper concentrates on a new type of asynchronous modular contactor. To get the contactor movement characteristics, the dynamic model of the electromagnetic system is established by MATLAB/SIMULINK. Then, according to the displacement curve of contactor, the breaking process and closing process is planned. The thought of closed loop control, by adjusting the parameters of PID controller, enables the contactor to operate as the planning displacement curve. In addition, to achieve no arc or micro arc breaking and no bounce or micro bounce closing , a displacement closed loop control system for contactor is designed.

  14. CENTRIFUGAL SEPARATORS

    Science.gov (United States)

    Skarstrom, C.

    1959-03-10

    A centrifugal separator is described for separating gaseous mixtures where the temperature gradients both longitudinally and radially of the centrifuge may be controlled effectively to produce a maximum separation of the process gases flowing through. Tbe invention provides for the balancing of increases and decreases in temperature in various zones of the centrifuge chamber as the result of compression and expansions respectively, of process gases and may be employed effectively both to neutralize harmful temperature gradients and to utilize beneficial temperaturc gradients within the centrifuge.

  15. Centrifugal pumps

    CERN Document Server

    Anderson, HH

    1981-01-01

    Centrifugal Pumps describes the whole range of the centrifugal pump (mixed flow and axial flow pumps are dealt with more briefly), with emphasis on the development of the boiler feed pump. Organized into 46 chapters, this book discusses the general hydrodynamic principles, performance, dimensions, type number, flow, and efficiency of centrifugal pumps. This text also explains the pumps performance; entry conditions and cavitation; speed and dimensions for a given duty; and losses. Some chapters further describe centrifugal pump mechanical design, installation, monitoring, and maintenance. The

  16. Gas centrifuge purge method

    Science.gov (United States)

    Theurich, Gordon R.

    1976-01-01

    1. In a method of separating isotopes in a high speed gas centrifuge wherein a vertically oriented cylindrical rotor bowl is adapted to rotate about its axis within an evacuated chamber, and wherein an annular molecular pump having an intake end and a discharge end encircles the uppermost portion of said rotor bowl, said molecular pump being attached along its periphery in a leak-tight manner to said evacuated chamber, and wherein end cap closure means are affixed to the upper end of said rotor bowl, and a process gas withdrawal and insertion system enters said bowl through said end cap closure means, said evacuated chamber, molecular pump and end cap defining an upper zone at the discharge end of said molecular pump, said evacuated chamber, molecular pump and rotor bowl defining a lower annular zone at the intake end of said molecular pump, a method for removing gases from said upper and lower zones during centrifuge operation with a minimum loss of process gas from said rotor bowl, comprising, in combination: continuously measuring the pressure in said upper zone, pumping gas from said lower zone from the time the pressure in said upper zone equals a first preselected value until the pressure in said upper zone is equal to a second preselected value, said first preselected value being greater than said second preselected value, and continuously pumping gas from said upper zone from the time the pressure in said upper zone equals a third preselected value until the pressure in said upper zone is equal to a fourth preselected value, said third preselected value being greater than said first, second and fourth preselected values.

  17. Study on reliability technology of contactor relay

    Institute of Scientific and Technical Information of China (English)

    LIU Guo-jin; ZHAO Jing-ying; WANG Hai-tao; YANG Chen-guang; SUN Shun-li

    2007-01-01

    In this paper, the reliability of contactor relay is studied. There are three main parts about reliability test and analysis. First, in order to analyze reliability level of contact relay, the failure ratio ranks are established as index base on the product level. Second, the reliability test method is put forward. The sample plan of reliability compliance test is gained from reliability sample theory. The failure criterion is ensured according to the failure modes of contactor relay. Third, after reliability test experiment, the analysis of failure physics is made and the failure reason is found.

  18. Micro contactor based on isotachophoretic sample transport.

    Science.gov (United States)

    Goet, Gabriele; Baier, Tobias; Hardt, Steffen

    2009-12-21

    It is demonstrated how isotachophoresis (ITP) in a microfluidic device may be utilized to bring two small sample volumes into contact in a well-controlled manner. The ITP contactor serves a similar purpose as micromixers that are designed to mix two species rapidly in a microfluidic channel. In contrast to many micromixers, the ITP contactor does not require complex channel architectures and allows a sample processing in the spirit of "digital microfluidics", i.e. the samples always remain in a compact volume. It is shown that the ITP zone transport through microchannels proceeds in a reproducible and predictable manner, and that the sample trajectories follow simple relationships obtained from Ohm's law. Firstly, the micro contactor can be used to synchronize two ITP zones having reached a channel at different points in time. Secondly, fulfilling its actual purpose it is capable of bringing two samples in molecular contact via an interpenetration of ITP zones. It is demonstrated that the contacting time is proportional to the ITP zone extension. This opens up the possibility of using that type of device as a special type of micromixer with "mixing times" significantly below one second and an option to regulate the duration of contact through specific parameters such as the sample volume. Finally, it is shown how the micro contactor can be utilized to conduct a hybridization reaction between two ITP zones containing complementary DNA strands.

  19. Thermal Simulation of AC Electromagnetic Contactor

    Institute of Scientific and Technical Information of China (English)

    NIUChun-ping; CHENDe-gui; ZHANGJing-shu; LIXing-wen

    2005-01-01

    Transient magnetic circuit method is adopted to calculate the power loss in winding and shading coil. Based on the analysis of heat transfer process in AC contactor, a thermal model is proposed and the temperature field distribution is simulated with 3-D FEM of ANSYS.Comparison of simulation results with measurements shows that the proposed method is effective.

  20. Subcutaneous granuloma annulare

    Directory of Open Access Journals (Sweden)

    Dhar Sandipan

    1994-01-01

    Full Text Available Two cases of subcutaneos granuloma annulare are reported. Clinical presentation was in the form of hard subcutaneous nodules; histopathology confirmed the clinical diagnosis. The cases were unique because of onset in adult hood, occurrence over unusual sites and absence of classical lesions of granuloma annulare elsewhere.

  1. Subcutaneous granuloma annulare

    Directory of Open Access Journals (Sweden)

    Dhar Sandipan

    1993-01-01

    Full Text Available Two cases of subcutaneous granuloma annulare are reported. Clinical presentation was in the form of hard subcutaneous nodules, histopathology confirmed the clinical diagnosis. The cases were unique because of onset in adult age, occurrence over unusual sites and absence of classical lesions of granuloma annulare elsewhere.

  2. Centrifugally activated bearing for high-speed rotating machinery

    Science.gov (United States)

    Post, Richard F.

    1994-01-01

    A centrifugally activated bearing is disclosed. The bearing includes an annular member that extends laterally and radially from a central axis. A rotating member that rotates about the central axis relative to the annular member is also included. The rotating member has an interior chamber that surrounds the central axis and in which the annular member is suspended. Furthermore, the interior chamber has a concave shape for retaining a lubricant therein while the rotating member is at rest and for retaining a lubricant therein while the rotating member is rotating. The concave shape is such that while the rotating member is rotating a centrifugal force causes a lubricant to be forced away from the central axis to form a cylindrical surface having an axis collinear with the central axis. This centrifugally displaced lubricant provides restoring forces to counteract lateral displacement during operation.

  3. Continuous fluidized-bed contactor with recycle of sorbent

    Science.gov (United States)

    Scott, Charles D.; Petersen, James N.; Davison, Brian H.

    1996-01-01

    A continuous fluidized-bed contactor containing sorbent particles is used to remove solutes from liquid solvents. As the sorbent particles, for example gel beads, sorb the solute, for example metal ion species, the sorbent particles tend to decrease in diameter. These smaller loaded sorbent particles rise to the top of the contactor, as larger sorbent particles remain at the bottom of the contactor as a result of normal hydraulic forces. The smaller loaded sorbent particles are then recovered, regenerated, and reintroduced into the contactor. Alternatively, the loaded sorbent particles may also slightly increase in diameter, or exhibit no change in diameter but an increase in density. As a result of normal hydraulic forces the larger loaded sorbent particles fall to the bottom of the contactor. The larger loaded sorbent particles are then recovered, regenerated, and reintroduced into the contactor.

  4. Annular pancreas (image)

    Science.gov (United States)

    Annular pancreas is an abnormal ring or collar of pancreatic tissue that encircles the duodenum (the part of the ... intestine that connects to stomach). This portion of pancreas can constrict the duodenum and block or impair ...

  5. Rotating biological contactors: the Canadian experience

    Energy Technology Data Exchange (ETDEWEB)

    Cuenca, Manuel A. [Ryerson Polytechnical Univ., Toronto, ON (Canada). Chemical Engineering Dept.; Smith, Tom [CMS Rotordisk Inc., Concord, ON (Canada); Vianna, Arlinda C. [Servico Nacional de Aprendizagem Industrial (SENAI), Salvador, BA (Brazil)

    1993-12-31

    In fifteen years, Rotating Biological Contactors (RBC) have become one of the most attractive technologies for secondary wastewater treatment. The present work is a review of the evolution of RBC technology in the last twenty years. In addition, the status of the technology in Canada is described, emphasizing industrial facilities and landfill leachate treatment. An enumeration of the most relevant development areas is included. (author). 34 refs., 3 figs., 7 tabs.

  6. Hollow fiber membrane contactor as a gas–liquid model contactor

    NARCIS (Netherlands)

    Dindore, V.Y.; Brilman, D.W.F.; Versteeg, G.F.

    2005-01-01

    Microporous hollow fiber gas–liquid membrane contactors have a fixed and well-defined gas–liquid interfacial area. The liquid flow through the hollow fiber is laminar, thus the liquid side hydrodynamics are well known. This allows the accurate calculation of the fiber side physical mass transfer coe

  7. Hollow fiber membrane contactor as a gas-liquid model contactor

    NARCIS (Netherlands)

    Dindore, V. Y.; Brilman, D. W. F.; Versteeg, G. F.

    2005-01-01

    Microporous hollow fiber gas-liquid membrane contactors have a fixed and well-defined gas-liquid interfacial area. The liquid flow through the hollow fiber is laminar, thus the liquid side hydrodynamics are well known. This allows the accurate calculation of the fiber side physical mass transfer coe

  8. Centrifugal pumps

    CERN Document Server

    Gülich, Johann Friedrich

    2014-01-01

    This book gives an unparalleled, up-to-date, in-depth treatment of all kinds of flow phenomena encountered in centrifugal pumps including the complex interactions of fluid flow with vibrations and wear of materials. The scope includes all aspects of hydraulic design, 3D-flow phenomena and partload operation, cavitation, numerical flow calculations, hydraulic forces, pressure pulsations, noise, pump vibrations (notably bearing housing vibration diagnostics and remedies), pipe vibrations, pump characteristics and pump operation, design of intake structures, the effects of highly viscous flows, pumping of gas-liquid mixtures, hydraulic transport of solids, fatigue damage to impellers or diffusers, material selection under the aspects of fatigue, corrosion, erosion-corrosion or hydro-abrasive wear, pump selection, and hydraulic quality criteria. As a novelty, the 3rd ed. brings a fully analytical design method for radial impellers, which eliminates the arbitrary choices inherent to former design procedures. The d...

  9. Single Stage Contactor Testing Of The Next Generation Solvent Blend

    Energy Technology Data Exchange (ETDEWEB)

    Herman, D. T.; Peters, T. B.; Duignan, M. R.; Williams, M. R.; Poirier, M. R.; Brass, E. A.; Garrison, A. G.; Ketusky, E. T.

    2014-01-06

    The Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) facility at the Savannah River Site (SRS) is actively pursuing the transition from the current BOBCalixC6 based solvent to the Next Generation Solvent (NGS)-MCU solvent to increase the cesium decontamination factor. To support this integration of NGS into the MCU facility the Savannah River National Laboratory (SRNL) performed testing of a blend of the NGS (MaxCalix based solvent) with the current solvent (BOBCalixC6 based solvent) for the removal of cesium (Cs) from the liquid salt waste stream. This testing utilized a blend of BOBCalixC6 based solvent and the NGS with the new extractant, MaxCalix, as well as a new suppressor, tris(3,7dimethyloctyl) guanidine. Single stage tests were conducted using the full size V-05 and V-10 liquid-to-liquid centrifugal contactors installed at SRNL. These tests were designed to determine the mass transfer and hydraulic characteristics with the NGS solvent blended with the projected heel of the BOBCalixC6 based solvent that will exist in MCU at time of transition. The test program evaluated the amount of organic carryover and the droplet size of the organic carryover phases using several analytical methods. The results indicate that hydraulically, the NGS solvent performed hydraulically similar to the current solvent which was expected. For the organic carryover 93% of the solvent is predicted to be recovered from the stripping operation and 96% from the extraction operation. As for the mass transfer, the NGS solvent significantly improved the cesium DF by at least an order of magnitude when extrapolating the One-stage results to actual Seven-stage extraction operation with a stage efficiency of 95%.

  10. Generalized granuloma annulare

    Directory of Open Access Journals (Sweden)

    Khatri M

    1995-01-01

    Full Text Available A 35-years-old female patient had generalized pruritic papular lesions, distributed like dermatitis herpetiformis for last 4 years. Histopathologic changes were typical of granuloma annulare with negative results of direct immunofluorescence. The patient did not have association of diabetes mellitus or any other systemic disease. She failed to respond to dapsone therapy and 13-cis-retinoic acid.

  11. Low cost membrane contactors based on hollow fibres

    Directory of Open Access Journals (Sweden)

    Raudensky Miroslav

    2012-04-01

    Full Text Available Membrane contactors are used to solve different chemical engineering tasks (e.g. water saturation with gases. Such elements are traditionally used for bubble less oxidation of blood. However, their industrial applications are rather limited by their high investment costs. This is probably the main reason why membrane contactors are not used so widely, e.g. classical absorbers, etc. If potted bundles of hollow fibres are available, then it is a relatively simple task to design an ad hoc membrane contactor. However, it must be emphasised that to achieve the highest mass transfer efficiency requires a rather time-consuming tuning of each ad hoc designed contactor. To check the differences by water evaporation were aligned two modes, the water inside the hollow fibre membrane and fan air outside, next with the water outsides and flowing pressure air inside the membrane.

  12. Annular recuperator design

    Science.gov (United States)

    Kang, Yungmo

    2005-10-04

    An annular heat recuperator is formed with alternating hot and cold cells to separate counter-flowing hot and cold fluid streams. Each cold cell has a fluid inlet formed in the inner diameter of the recuperator near one axial end, and a fluid outlet formed in the outer diameter of the recuperator near the other axial end to evenly distribute fluid mass flow throughout the cell. Cold cells may be joined with the outlet of one cell fluidly connected to the inlet of an adjacent downstream cell to form multi-stage cells.

  13. [Disseminated granuloma annulare].

    Science.gov (United States)

    Kansky, A

    1975-09-01

    A case of generalized granuloma annulare in a 55 year old man is reported. The disease appeared five years before the first admission to the hospital. A large number of bluish-red or skin-colour papules were scattered mainly around the earlobes, buttocks and on the extremities. Some of the lesions were lined up in rings or plaques. Small depigmented and brownish scars were present. Two biopsies revealed characteristic foci of complete collagen degeneration accompanied by a palisading infiltrate in the upper dermis. Treatment with tuberculostatics and antimalarics was without improvement. The lesions cleared after a course of prednison, but reappeared when the drug was discontinued.

  14. On the mixing enhancement in annular flows

    Science.gov (United States)

    Moradi, H. V.; Floryan, J. M.

    2017-02-01

    The potential for mixing enhancement associated with the use of axisymmetric ribs in annular flows has been analyzed. The enhancement relies on the use of streamwise vortices produced by the centrifugal instability. Conditions leading to the formation of such vortices have been established for a wide range of geometric parameters of interest using linear stability theory. It has been demonstrated that vortices can be formed only in the presence of ribs with O(1) wavelengths. Slopes of the bounding walls in the case of the long wavelength ribs are too small to create centrifugal forces sufficient for flow destabilization. In the case of short wavelength ribs, the slopes become excessively large, resulting in the stream moving away from the wall and becoming rectilinear and, thus, reducing the magnitude of the centrifugal force field. It has been shown that decreasing the annulus' radius reduces the critical Reynolds number when ribs are placed at the inner cylinder but increases when the ribs are placed at the outer cylinder. The onset of the shear-driven instability has been investigated as the resulting travelling waves may interfere with the formation of vortices. It has been shown that the axisymmetric waves play the critical role for annuli with large radii while the spiral waves play the critical role for annuli with small radii. The ribs always reduce the critical Reynolds number for the travelling waves when compared with the onset conditions for smooth annuli. The conduit geometries giving preference to the formation of vortices while avoiding creation of the travelling waves have been identified. It is demonstrated that predictions of flow characteristics determined through the analysis of sinusoidal ribs provide a good approximation of the flow response to ribs of arbitrary shape.

  15. Multiple annular linear diffractive axicons.

    Science.gov (United States)

    Bialic, Emilie; de la Tocnaye, Jean-Louis de Bougrenet

    2011-04-01

    We propose a chromatic analysis of multiple annular linear diffractive axicons. Large aperture axicons are optical devices providing achromatic nondiffracting beams, with an extended depth of focus, when illuminated by a white light source, due to chromatic foci superimposition. Annular apertures introduce chromatic foci separation, and because chromatic aberrations result in focal segment axial shifts, polychromatic imaging properties are partially lost. We investigate here various design parameters that can be used to achieve color splitting, filtering, and combining using these properties. In order to improve the low-power efficiency of a single annular axicon, we suggest a spatial multiplexing of concentric annular axicons with different sizes and periods we call multiple annular aperture diffractive axicons (MALDAs). These are chosen to maintain focal depths while enabling color imaging with sufficient diffraction efficiency. Illustrations are given for binary phase diffractive axicons, considering technical aspects such as grating design wavelength and phase dependence due to the grating thickness.

  16. Physical processes associated with current collection by plasma contactors

    Science.gov (United States)

    Katz, Ira; Davis, Victoria A.

    1990-01-01

    Recent flight data confirms laboratory observations that the release of neutral gas increases plasma sheath currents. Plasma contactors are devices which release a partially ionized gas in order to enhance the current flow between a spacecraft and the space plasma. Ionization of the expellant gas and the formation of a double layer between the anode plasma and the space plasma are the dominant physical processes. A theory is presented of the interaction between the contactor plasma and the background plasma. The conditions for formation of a double layer between the two plasmas are derived. Double layer formation is shown to be a consequence of the nonlinear response of the plasmas to changes in potential. Numerical calculations based upon this model are compared with laboratory measurements of current collection by hollow cathode-based plasma contactors.

  17. Centrifuge modeling of monopiles

    DEFF Research Database (Denmark)

    Klinkvort, Rasmus Tofte

    2010-01-01

    To gain a larger knowledge of the monopile foundation concept, centrifuge modeling is used by the geotechnical group at DTU. The centrifuge operated at DTU is a beam centrifuge and was built in 1976. In the recent years it has been upgraded with onboard data acquisition and control systems. The c...... from centrifuge tests performed on large diameter piles installed in dry sand.......To gain a larger knowledge of the monopile foundation concept, centrifuge modeling is used by the geotechnical group at DTU. The centrifuge operated at DTU is a beam centrifuge and was built in 1976. In the recent years it has been upgraded with onboard data acquisition and control systems....... The capabilities of the centrifuge at DTU makes it possible to obtain a scale factor of 85 in experiments which equals a soil volume in prototype scale of a diameter of 40 meters and a depth of 40 meters. This paper describes centrifuge modeling theory, the centrifuge setup at DTU and as an example show results...

  18. Annular Hybrid Rocket Motor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Engineers at SpaceDev have conducted a preliminary design and analysis of a proprietary annular design concept for a hybrid motor. A U.S. Patent application has been...

  19. Annular Elastolytic Giant Cell Granuloma

    Directory of Open Access Journals (Sweden)

    Khandpur Sujay

    2001-01-01

    Full Text Available The clinical and histopathological features of annular elastolytic giant cell granuloma in a 42â€"year-old female patient are described. The condition presented as annular erythematous plaques over sun- exposed skin sparing the face. Histopathology revealed dense granulomatous infiltrate consisting of numerous giant cells and lymphohistiocytes without any palisading arrangement or necrobiosis. The features differentiating it from other similar granulomatous disorders are discussed.

  20. Manufacture of annular cermet articles

    Science.gov (United States)

    Forsberg, Charles W.; Sikka, Vinod K.

    2004-11-02

    A method to produce annular-shaped, metal-clad cermet components directly produces the form and avoids multiple fabrication steps such as rolling and welding. The method includes the steps of: providing an annular hollow form with inner and outer side walls; filling the form with a particulate mixture of ceramic and metal; closing, evacuating, and hermetically sealing the form; heating the form to an appropriate temperature; and applying force to consolidate the particulate mixture into solid cermet.

  1. Rotating Biological Contactors (RBC's). Student Manual. Biological Treatment Process Control.

    Science.gov (United States)

    Zickefoose, Charles S.

    This student manual provides the textual material for a unit on rotating biological contactors (RBC's). Topic areas considered include: (1) flow patterns of water through RBC installations; (2) basic concepts (shaft and stage); (3) characteristics of biomass; (4) mechanical features (bearings, mechanical drive systems, and air drive systems); (5)…

  2. Carbon Dioxide Absorption in a Membrane Contactor with Color Change

    Science.gov (United States)

    Pantaleao, Ines; Portugal, Ana F.; Mendes, Adelio; Gabriel, Joaquim

    2010-01-01

    A pedagogical experiment is described to examine the physical absorption of gases, in this case carbon dioxide, in a hollow fiber membrane contactor (HFMC) where the absorption concentration profile can be followed by a color change. The HFMC is used to teach important concepts and can be used in interesting applications for students, such as…

  3. METHOD OF CENTRIFUGE OPERATION

    Science.gov (United States)

    Cohen, K.

    1960-05-10

    A method of isotope separation is described in which two streams are flowed axially of, and countercurrently through, a cylindrical centrifuge bowl. Under the influence of a centrifugal field, the light fraction is concentrated in a stream flowing through the central portion of the bowl, whereas the heavy fraction is concentrated in a stream at the periphery thereof.

  4. Annular lipoatrophy of the ankles.

    Science.gov (United States)

    Dimson, Otobia G; Esterly, Nancy B

    2006-02-01

    Lipoatrophic panniculitis likely represents a group of disorders characterized by an inflammatory panniculitis followed by lipoatrophy. It occurs locally in a variety of settings and has been reported in the literature under various terms, including annular atrophic connective tissue panniculitis of the ankles, annular and semicircular lipoatrophy, abdominal lipoatrophy, and connective tissue panniculitis. Herein, a case of annular lipoatrophy of the ankles is described in a 6-year-old girl with autoimmune thyroid disease. Histologically, a mixed lobular panniculitis with lipophages was present. This pattern resembles that seen in lipoatrophic panniculitis. After a single, acute episode of an inflammatory process with subsequent lipoatrophy, her skin lesions have stabilized for 2 years requiring no treatment.

  5. Centrifugal pump handbook

    CERN Document Server

    Pumps, Sulzer

    2010-01-01

    This long-awaited new edition is the complete reference for engineers and designers working on pump design and development or using centrifugal pumps in the field. This authoritative guide has been developed with access to the technical expertise of the leading centrifugal pump developer, Sulzer Pumps. In addition to providing the most comprehensive centrifugal pump theory and design reference with detailed material on cavitation, erosion, selection of materials, rotor vibration behavior and forces acting on pumps, the handbook also covers key pumping applications topics and operational

  6. Electrolytically aided denitrification on a rotating biological contactor.

    Science.gov (United States)

    Rodziewicz, Joanna; Filipkowska, Urszula; Dziadkiewicz, Ewa

    2011-01-01

    The study was conducted at a bench scale on a rotating biological contactor under both conventional conditions (without the flow of electric current) and with the passage of an electric current having the following densities: 0.2 A m(-2), 0.8 A m(-)2 and 1.5 A m(-2). Stainless-steel discs covered with an immobilized biofilm served as a cathode, whereas an electrode made of stainless steel immersed in the wastewater of the flow tank of the contactor served as an anode. Experiments were carried out on municipal wastewater containing nitrogen in the organic and ammonium forms. The highest efficiency of nitrogen removal was observed with the passage of electric current at the density of 0.2 A m(-2). The efficiency of the denitrification process was over 64% and the nitrification efficiency was 93.4%.

  7. Membrane contactor assisted extraction/reaction process employing ionic liquids

    Science.gov (United States)

    Lin, Yupo J.; Snyder, Seth W.

    2012-02-07

    The present invention relates to a functionalized membrane contactor extraction/reaction system and method for extracting target species from multi-phase solutions utilizing ionic liquids. One preferred embodiment of the invented method and system relates to an extraction/reaction system wherein the ionic liquid extraction solutions act as both extraction solutions and reaction mediums, and allow simultaneous separation/reactions not possible with prior art technology.

  8. Eosinophilic annular erythema in childhood - Case report*

    Science.gov (United States)

    Abarzúa, Alvaro; Giesen, Laura; Silva, Sergio; González, Sergio

    2016-01-01

    Eosinophilic annular erythema is a rare, benign, recurrent disease, clinically characterized by persistent, annular, erythematous lesions, revealing histopathologically perivascular infiltrates with abundant eosinophils. This report describes an unusual case of eosinophilic annular erythema in a 3-year-old female, requiring sustained doses of hydroxychloroquine to be adequately controlled. PMID:27579748

  9. Integration issues of a plasma contactor Power Electronics Unit

    Science.gov (United States)

    Pinero, Luis R.; York, Kenneth W.; Bowers, Glen E.

    1995-06-01

    A hollow cathode-based plasma contactor is baselined on International Space Station Alpha (ISSA) for spacecraft charge control. The plasma contactor system consists of a hollow cathode assembly (HCA), a power electronics unit (PEU), and an expellant management unit (EMU). The plasma contactor has recently been required to operate in a cyclic mode to conserve xenon expellant and extend system life. Originally, a DC cathode heater converter was baselined for a continuous operation mode because only a few ignitions of the hollow cathode were expected. However, for cyclic operation, a DC heater supply can potentially result in hollow cathode heater component failure due to the DC electrostatic field. This can prevent the heater from attaining the proper cathode tip temperature for reliable ignition of the hollow cathode. To mitigate this problem, an AC cathode heater supply was therefore designed, fabricated, and installed into a modified PEU. The PEU was tested using resistive loads and then integrated with an engineering model hollow cathode to demonstrate stable steady-state operation. Integration issues such as the effect of line and load impedance on the output of the AC cathode heater supply and the characterization of the temperature profile of the heater under AC excitation were investigated.

  10. Integration issues of a plasma contactor Power Electronics Unit

    Science.gov (United States)

    Pinero, Luis R.; York, Kenneth W.; Bowers, Glen E.

    1995-01-01

    A hollow cathode-based plasma contactor is baselined on International Space Station Alpha (ISSA) for spacecraft charge control. The plasma contactor system consists of a hollow cathode assembly (HCA), a power electronics unit (PEU), and an expellant management unit (EMU). The plasma contactor has recently been required to operate in a cyclic mode to conserve xenon expellant and extend system life. Originally, a DC cathode heater converter was baselined for a continuous operation mode because only a few ignitions of the hollow cathode were expected. However, for cyclic operation, a DC heater supply can potentially result in hollow cathode heater component failure due to the DC electrostatic field. This can prevent the heater from attaining the proper cathode tip temperature for reliable ignition of the hollow cathode. To mitigate this problem, an AC cathode heater supply was therefore designed, fabricated, and installed into a modified PEU. The PEU was tested using resistive loads and then integrated with an engineering model hollow cathode to demonstrate stable steady-state operation. Integration issues such as the effect of line and load impedance on the output of the AC cathode heater supply and the characterization of the temperature profile of the heater under AC excitation were investigated.

  11. Benign concentric annular macular dystrophy

    Directory of Open Access Journals (Sweden)

    Luísa Salles de Moura Mendonça

    2015-06-01

    Full Text Available The purpose of the authors is to show clinical findings of a patient with benign concentric annular macular dystrophy, which is an unusual condition, and part of the "bull’s eye" maculopathy differential diagnosis. An ophthalmologic examination with color perception, fluorescein angiography, and ocular electrophysiology was performed.

  12. A Computer Model for Teaching the Dynamic Behavior of AC Contactors

    Science.gov (United States)

    Ruiz, J.-R. R.; Espinosa, A. G.; Romeral, L.

    2010-01-01

    Ac-powered contactors are extensively used in industry in applications such as automatic electrical devices, motor starters, and heaters. In this work, a practical session that allows students to model and simulate the dynamic behavior of ac-powered electromechanical contactors is presented. Simulation is carried out using a rigorous parametric…

  13. Maryland Centrifugal Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Hassam, Adil; Ellis, Richard F

    2016-12-22

    The Maryland Centrifugal Experiment (MCX) Project has investigated the concepts of centrifugal plasma confinement and stabilization of instabilities by velocity shear. The basic requirement is supersonic plasma rotation about a shaped, open magnetic field. Overall, the MCX Project attained three primary goals that were set out at the start of the project. First, supersonic rotation at Mach number upto 2.5 was obtained. Second, turbulence from flute interchange modes was found considerably reduced from conventional. Third, plasma pressure was contained along the field, as evidenced by density drops of x10 from the center to the mirror throats.

  14. Effect of Organic Loading on Rotating Biological Contactor Efficiency

    Directory of Open Access Journals (Sweden)

    Kossay K. Al-Ahmady

    2005-12-01

    Full Text Available Organic loading (weight per unit time per volume is useful for the design of rotating biological contactors (RBC and for comparison with the other processes such as activated sludge or oxidation ponds. The present study puts emphasis on the significance of this control or design parameter because it allows direct comparison of the RBC system's performance when operated under various circumstances and with different kinds of wastewater. The results of the paper proved that, the COD removal in rotating biological contactor systems is a function of the organic loading rate. However, each of the wastewater concentration and flow rate are also influence on the system efficiency but theirs impact can be combined by the effect of organic loading. The majority of COD removal (40-85 % of the total removal depending on the organic loading applied occurs in the first stages of the system. There is a strong correlation between the organic loading and the concentration of the suspended solids in the rotating biological contactor basin. At higher loadings higher concentrations noted. At a loading of about, (24 g/m2.d suspended solids were 225, 125, 35, and 25 mg/L in the first, second, third and, the fourth stage respectively. To achieve an effluent quality of (BOD < 25 mg/L, COD < 60 mg/L, the system must be operated on organic loadings of about (22 gBOD/m2.d and 65 gCOD/m2.d respectively. For nitrification process, the system must be designed to operate at organic loading of about (10 g/m2.d or less and, the reactor or basin volume should be designed to achieve a hydraulic loading of about (40 L/m2.d or less.

  15. Perceived radial translation during centrifugation

    NARCIS (Netherlands)

    Bos, J.E.; Correia Grácio, B.J.

    2015-01-01

    BACKGROUND: Linear acceleration generally gives rise to translation perception. Centripetal acceleration during centrifugation, however, has never been reported giving rise to a radial, inward translation perception. OBJECTIVE: To study whether centrifugation can induce a radial translation percepti

  16. Pumps, Centrifugal and Reciprocating

    Science.gov (United States)

    2011-04-27

    guidance for preparing test plans and conducting test programs to evaluate the effectiveness and suitability for military use of centrifugal and...This page is intentionally blank.)   US ARMY DEVELOPMENTAL TEST COMMAND TEST...Satisfy the needs of MIL-STD-4612. High-Altitude Electromagnetic Pulse ( HEMP ) Test Facility Satisfy the needs of MIL-STD-461. Rail Impact Test

  17. Centrifugal atomisation of alloys

    Energy Technology Data Exchange (ETDEWEB)

    Li Huiping [School of Mechanical and Materials Engineering, Univ. of Surrey, Guilford (United Kingdom); Dept. of Inorganic Materials, East China Univ. of Science and Technology, Shanghai, SH (China); Tsakiropoulos, P. [School of Mechanical and Materials Engineering, Univ. of Surrey, Guilford (United Kingdom); Johnson, T. [Tetronics Ltd., Faringdon, Oxfordshire (United Kingdom)

    2001-07-01

    Centrifugal atomisation using a rotating disk is described and compared to REP and PREP. Results of calculations of models describing the interaction of a melt with a rotating disk, the formation of thin film on the disk and the break up of the thin film and its atomisation at the edge of the disk are compared with experimental results. (orig.)

  18. Central centrifugal cicatricial alopecia

    Directory of Open Access Journals (Sweden)

    Collin Blattner

    2013-01-01

    Full Text Available Central centrifugal cicatricial alopecia is a common cause of progressive permanent apical alopecia. This unique form of alopecia includes entities previously know as "hot comb alopecia," "follicular degeneration syndrome," "pseudopelade" in African Americans and "central elliptical pseudopelade" in Caucasians. The etiology appears to be multifactorial and the condition occurs in all races.

  19. A Reconfigurable Radiation Pattern Annular Slot Antenna

    OpenAIRE

    Aziz, NA; Radhi, A; Nilavalan, R

    2016-01-01

    This paper contemplate a theoretical analysis of a pattern reconfigurable antenna using annular slot antenna operating in low frequency. A shorting pin is inserted to allow the annular slot antenna to have an omnidirectional radiation pattern like a monopole antenna. The reconfigurable antenna consists of numerous metal cylinders arranged around the annular slot antenna. By controlling pin diodes associated with the metal cylinders, the antenna is capable of working up in different dire...

  20. A new method for liposome preparation using a membrane contactor.

    Science.gov (United States)

    Jaafar-Maalej, Chiraz; Charcosset, Catherine; Fessi, Hatem

    2011-09-01

    In this article, we present a novel, scalable liposomal preparation technique suitable for the entrapment of pharmaceutical agents into liposomes. This new method is based on the ethanol-injection technique and uses a membrane contactor module, specifically designed for colloidal system preparation. In order to investigate the process, the influence of key parameters on liposome characteristics was studied. It has been established that vesicle-size distribution decreased with a decrease of the organic-phase pressure, an increase of the aqueous-phase flow rate, and a decrease of the phospholipid concentration. Additionally, special attention was paid on reproducibility and long-term stability of lipid vesicles, confirming the robustness of the membrane contactor-based technique. On the other hand, drug-loaded liposomes were prepared and filled with two hydrophobic drug models. High entrapment-efficiency values were successfully achieved for indomethacin (63%) and beclomethasone dipropionate (98%). Transmission electron microscopy images revealed nanometric quasispherical-shaped multilamellar vesicles (size ranging from 50 to 160 nm).

  1. Indicators for technological, environmental and economic sustainability of ozone contactors.

    Science.gov (United States)

    Zhang, Jie; Tejada-Martinez, Andres E; Lei, Hongxia; Zhang, Qiong

    2016-09-15

    Various studies have attempted to improve disinfection efficiency as a way to improve the sustainability of ozone disinfection which is a critical unit process for water treatment. Baffling factor, CT10, and log-inactivation are commonly used indicators for quantifying disinfection credits. However the applicability of these indicators and the relationship between these indicators have not been investigated in depth. This study simulated flow, tracer transport, and chemical species transport in a full-scale ozone contactor operated by the City of Tampa Water Department and six other modified designs using computational fluid dynamics (CFD). Through analysis of the simulation results, we found that baffling factor and CT10 are not optimal indicators of disinfection performance. We also found that the relationship between effluent CT obtained from CT transport simulation and baffling factor depends on the location of ozone release. In addition, we analyzed the environmental and economic impacts of ozone contactor designs and upgrades and developed a composite indicator to quantify the sustainability in technological, environmental and economic dimensions.

  2. Centrifugal unbalance detection system

    Science.gov (United States)

    Cordaro, Joseph V.; Reeves, George; Mets, Michael

    2002-01-01

    A system consisting of an accelerometer sensor attached to a centrifuge enclosure for sensing vibrations and outputting a signal in the form of a sine wave with an amplitude and frequency that is passed through a pre-amp to convert it to a voltage signal, a low pass filter for removing extraneous noise, an A/D converter and a processor and algorithm for operating on the signal, whereby the algorithm interprets the amplitude and frequency associated with the signal and once an amplitude threshold has been exceeded the algorithm begins to count cycles during a predetermined time period and if a given number of complete cycles exceeds the frequency threshold during the predetermined time period, the system shuts down the centrifuge.

  3. Centrifugally decoupling touchdown bearings

    Science.gov (United States)

    Post, Richard F

    2014-06-24

    Centrifugally decoupling mechanical bearing systems provide thin tensioned metallic ribbons contained in a support structure. This assembly rotates around a stationary shaft being centered at low speeds by the action of the metal ribbons. Tension springs are connected on one end to the ribbons and on the other end to the support structure. The ribbons pass through slots in the inner ring of the support structure. The spring preloading thus insures contact (or near-contact) between the ribbons and the shaft at rotation speeds below the transition speed. Above this speed, however, the centrifugal force on the ribbons produces a tensile force on them that exceeds the spring tensile force so that the ribbons curve outward, effectively decoupling them from mechanical contact with the shaft. They still remain, however, in position to act as a touchdown bearing in case of abnormally high transverse accelerations.

  4. Confocal Annular Josephson Tunnel Junctions

    Science.gov (United States)

    Monaco, Roberto

    2016-09-01

    The physics of Josephson tunnel junctions drastically depends on their geometrical configurations and here we show that also tiny geometrical details play a determinant role. More specifically, we develop the theory of short and long annular Josephson tunnel junctions delimited by two confocal ellipses. The behavior of a circular annular Josephson tunnel junction is then seen to be simply a special case of the above result. For junctions having a normalized perimeter less than one, the threshold curves in the presence of an in-plane magnetic field of arbitrary orientations are derived and computed even in the case with trapped Josephson vortices. For longer junctions, a numerical analysis is carried out after the derivation of the appropriate motion equation for the Josephson phase. We found that the system is modeled by a modified and perturbed sine-Gordon equation with a space-dependent effective Josephson penetration length inversely proportional to the local junction width. Both the fluxon statics and dynamics are deeply affected by the non-uniform annulus width. Static zero-field multiple-fluxon solutions exist even in the presence of a large bias current. The tangential velocity of a traveling fluxon is not determined by the balance between the driving and drag forces due to the dissipative losses. Furthermore, the fluxon motion is characterized by a strong radial inward acceleration which causes electromagnetic radiation concentrated at the ellipse equatorial points.

  5. Soliton bunching in annular Josephson junctions

    DEFF Research Database (Denmark)

    Vernik, I.V; Lazarides, Nickos; Sørensen, Mads Peter

    1996-01-01

    By studying soliton (fluxon) motion in long annular Josephson junctions it is possible to avoid the influence of the boundaries and soliton-soliton collisions present in linear junctions. A new experimental design consisting of a niobium coil placed on top of an annular junction has been used...

  6. OZONE CONTACTOR FLOW VISUALIZATION AND CHARACTERIZATION USING 3-DIMENSIONAL LASER INDUCED FLUORESCENCE

    Science.gov (United States)

    Hydrodynamics of ozone contactors have a crucial impact on efficient inactivation of pathogens such as Cryptosporidium as well as control of disinfection byproducts such as bromate. Improper mixing behaviors including short-circuiting, internal recirculation and presence...

  7. Applying Closing Phase-Angle Control Technique in Bounce Reduction of AC Permanent Magnet Contactor

    Directory of Open Access Journals (Sweden)

    Chieh-Tsung Chi

    2009-01-01

    Full Text Available A new low-cost electronic control circuit actuator is proposed for minimizing the bouncing times of an AC permanent magnet (PM contactor after two contacts closing. The proposed new actuator overcomes the bouncing problem of an uncontrollable restrictions imposed by previously conventional AC electromagnetic (EM contactor based on the minimization of kinetic energy prior to two contacts impact. By choosing the closing phase angle of coil voltage on purpose, the bouncing problems of the movable contact during the closing process are then overcome. The using life of contacts is then prolonged and their operating reliability is improved as well. In order to validate the feasibility and effectiveness of the proposed method here, several simulation and experimental procedures were performed on a prototype of AC PM contactor in the laboratory. Testing results actually showed that bouncing problem of contactor's contacts during the closing process was to be controlled by using the proposed technology.

  8. Simulation Study of AC Contactor Dynamic Contacts Contact Pressure Based on ADAMS

    Directory of Open Access Journals (Sweden)

    Gu Yungao

    2015-01-01

    Full Text Available A multi-body dynamics simulation model of CJ20-25 AC contactor was established with Pro/E(Pro/Engineerin this paper. A coupling simulation with machine, electric, magnetic on the contactor has been achieved in this model. Dynamic parameters which were called use the secondary development technology of ADAMS. The dynamic contact pressure signal of an AC contactor was obtained with ADAMS’s own simultaneous solution such as electromagnetic suction, kinematics and dynamics equations. The simulation results and actual measurement of contactor contact pressure signals are very similar. However, the complexity of the measured contacts vibration is greater than the simulation results because the actual working condition is more complex. This result provides a theoretical foundation to the dynamic contacts contact pressure test.

  9. Optimum annular focusing by a phase plate

    CERN Document Server

    Arrizón, Victor; Aguirre-Olivas, Dilia; Mellado-Villaseñor, Gabriel

    2015-01-01

    Conventional light focusing, i. e. concentration of an extended optical field within a small area around a point, is a frequently used process in Optics. An important extension to conventional focusing is the generation of the annular focal field of an optical beam. We discuss a simple optical setup that achieves this kind of focusing employing a phase plate as unique optical component. We first establish the class of beams that being transmitted through the phase plate can be focused into an annular field with topological charge of arbitrary integer order q. Then, for each beam in this class we determine the plate transmittance that generates the focal field with the maximum possible peak intensity. In particular, we discuss and implement experimentally the optimum annular focusing of a Gaussian beam. The attributes of optimum annular focal fields, namely the high peak intensity, intensity gradient and narrow annular section, are advantageous for different applications of such structured fields.

  10. [Generalized granuloma annulare or diffuse dermal histiocytosis?].

    Science.gov (United States)

    Kretzschmar, L; Biel, K; Luger, T A; Goerdt, S

    1995-08-01

    Generalized granuloma annulare is a rare variant of granuloma annulare affecting the trunk and extremities with a multitude of lesions. In contrast to localized granuloma annulare, generalized granuloma annulare occurs in older patients, shows a stronger association with diabetes, and is characteristically chronic. Like our 55-year-old patient, most patients present with papules and annular plaques; less often, macular or non-annular lesions may be encountered. Histology often fails to show necrobiotic or necrotic connective tissue changes demarcated by a palisading granuloma. Instead, there are diffuse dermal, band-like or nodular aggregations of histiocytes intermingled with some multinucleated giant cells and a predominantly lymphocytic infiltrate in the periphery. Because of its special characteristics, it has been suggested that generalized granuloma annulare might constitute a separate disease entity and that it should be classed among the primary cutaneous histiocytoses as a diffuse dermal histiocytosis. Using immunohistochemistry to determine the macrophage phenotype of the lesional histiocytes, we have shown that generalized granuloma annulare is not a cutaneous histiocytosis. Neither MS-1 high-molecular-weight protein, a new specific marker for cutaneous non-Langerhans cell histiocytoses, nor CD1a, the well-known marker for Langerhans cells and Langerhans cell histiocytoses, is expressed by the lesional histiocytes of our patient. In contrast, the antigen expression pattern was diagnostic for non-infectious granulomas and was highly similar to that in localized granuloma annulare. In contrast to the successful treatment of localized granuloma annulare reported with intralesional interferon beta-1, systemic treatment with interferon alpha-2b (9 x 10(6) units three times a week) was ineffective.

  11. THE PERTURBATION SOLUTIONS OF THE FLOW IN A ROTATING CURVED ANNULAR PIPE

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this paper, the flow in a rotating curved annular pipe isexamined by a perturbation method. A second order perturbation solution is presented. The characteristics of the secondary flow and the axial flow are studied in detail.The study indicates that the loops of the secondary flow are more complex than those in a curved annular pipe without rotation and its numbers depend on the ratio of the Coriolis force to centrifugal force F. As F ≈- 1 , the secondary flow has eight loops and its intensity reaches the minimum value, and the distribution of the axial flow is like that of the Poiseuille flow. The position of the maximum axial velocity is pushed to either outer bend or inner bend, which is also determined by F.

  12. Treatment of Antibiotic Pharmaceutical Wastewater Using a Rotating Biological Contactor

    Directory of Open Access Journals (Sweden)

    Rongjun Su

    2015-01-01

    Full Text Available Rotating biological contactors (RBC are effective for treating wastewater, while they are rarely reported to be used for treating antibiotic pharmaceutical wastewater (APW. The current study investigates treatment of APW using an RBC. The effects of influent concentration, number of stages, and temperature on the remediation of APW were studied. The results indicated, even at low ambient temperature, 45% COD and 40% NH4+-N removal efficiencies. Moreover, the BOD5 removal efficiency was 85%. Microscopic observations illustrated that there were various active microorganisms displayed in the biofilms and their distribution changed from stage to stage. Compared with activated sludge, the biofilms in this study have higher content of dry matter and are easier to dehydrate and settle. Compared with current commercial incineration processes or advanced oxidation processes, RBC can greatly reduce the treatment cost. This research shows RBC is effective for such an inherently biorecalcitrant wastewater even at low ambient temperature.

  13. DENITRIFICATION PROCESS ENHANCING IN FOUR-STAGES ROTATING BIOLOGICAL CONTACTOR

    Directory of Open Access Journals (Sweden)

    Artur Mielcarek

    2016-06-01

    Full Text Available The aim of the study was to determine the degree of an organic substrate consumption in the denitrification process involving a biofilm in four-stages laboratory scale rotating biological contactor (RBC. The discs submergence was 40% of their diameter. Acetic acid, used as external carbon source, was fed to the fourth stage of RBC. Consumption of substrate was observed for 2 and 24 hours. For a shorter period there was the removal of 37.9 ± 1.8 mg N·m-2, while using 499,9 ± 33.2 mg O2·m-2 of organic compounds. The prolongation of the experiment duration guaranteed higher efficiency of denitrification. The ratio of organic substrate used to the amount of nitrogen removed was 13: 1 and 21: 1 for 2 and 24 hours respectively.

  14. Power consumption in gas-inducing-type mechanically agitated contactors

    Energy Technology Data Exchange (ETDEWEB)

    Saravanan, K.; Mundale, V.D.; Patwardhan, A.W.; Joshi, J.B. [Univ. of Bombay (India). Dept. of Chemical Technology

    1996-05-01

    Power consumption was measured in 0.57, 1.0, and 1.5 m i.d. gas inducing type of mechanically agitated contactors (GIMAC) using single and multiple impellers. The ratio of impeller diameter to vessel diameter was varied in the range of 0.13 < D/T < 0.59. The effect of liquid submergence from the top and impeller clearance from the vessel bottom was investigated in detail. In the case of multiple impeller systems, six different designs were investigated. The designs included pitched blade downflow turbine (PBTD), pitched blade upflow turbine (PBTU), downflow propeller (PD), upflow propeller (PU), straight bladed turbine (SBT) and disc turbine (DT). The effect of interimpeller clearance was studied for the multiple impeller system. The effect of impeller speed was studied in the range of 0.13 < N < 13.5 rotations/s. A mathematical model has been developed for power consumption before and after the onset of gas induction.

  15. CENTRIFUGAL MEMBRANE FILTRATION

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-10-01

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

  16. LOW-PRESSURE MEMBRANE CONTACTORS FOR CARBON DIOXIDE CAPTURE

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Richard; Kniep, Jay; Hao, Pingjiao; Chan, Chi Cheng; Nguyen, Vincent; Huang, Ivy; Amo, Karl; Freeman, Brice; Fulton, Don; Ly, Jennifer; Lipscomb, Glenn; Lou, Yuecun; Gogar, Ravikumar

    2014-09-30

    This final technical progress report describes work conducted by Membrane Technology and Research, Inc. (MTR) for the Department of Energy (DOE NETL) on development of low-pressure membrane contactors for carbon dioxide (CO2) capture from power plant flue gas (award number DE-FE0007553). The work was conducted from October 1, 2011 through September 30, 2014. The overall goal of this three-year project was to build and operate a prototype 500 m2 low-pressure sweep membrane module specifically designed to separate CO2 from coal-fired power plant flue gas. MTR was assisted in this project by a research group at the University of Toledo, which contributed to the computational fluid dynamics (CFD) analysis of module design and process simulation. This report details the work conducted to develop a new type of membrane contactor specifically designed for the high-gas-flow, low-pressure, countercurrent sweep operation required for affordable membrane-based CO2 capture at coal power plants. Work for this project included module development and testing, design and assembly of a large membrane module test unit at MTR, CFD comparative analysis of cross-flow, countercurrent, and novel partial-countercurrent sweep membrane module designs, CFD analysis of membrane spacers, design and fabrication of a 500 m2 membrane module skid for field tests, a detailed performance and cost analysis of the MTR CO2 capture process with low-pressure sweep modules, and a process design analysis of a membrane-hybrid separation process for CO2 removal from coal-fired flue gas. Key results for each major task are discussed in the report.

  17. Central centrifugal cicatricial alopecia.

    Science.gov (United States)

    Whiting, David A; Olsen, Elise A

    2008-01-01

    A progressive scarring alopecia of the central scalp is commonly seen in young to middle-aged females of African descent. It usually starts at the vertex or mid top of the scalp and gradually spreads centrifugally, hence, the unifying term of central centrifugal cicatricial alopecia. The clinical pattern is suggestive of female pattern alopecia, but a lack of follicular pores indicative of scarring is present. It can progress for years before slowly burning out. The etiology is unknown but genetic factors may be important. It is often associated with a history of traumatic hairstyling involving heat, traction, and chemicals. However, most patients of African descent without this disorder have similar styling habits. Nonetheless, avoidance of physical and chemical trauma to the scalp hair, the use of suitable shampoos and conditioners, and the encouragement of natural hairstyles may be helpful. Any infection should be treated. Topical or intralesional corticosteroids and systemic antibiotics may be useful and topical minoxidil should be tried with the hope of preventing further scarring and encouraging regrowth of recovering follicles. Current research into the etiology of this disorder will help to foster much-needed clinical trials of therapeutic agents.

  18. Centrifugal shot blast system

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-02-01

    This report describes a demonstration of Concrete cleaning, Inc., modified centrifugal shot blast technology to remove the paint coating from concrete flooring. This demonstration is part of the Chicago Pile-5 (CP-5) Large-Scale Demonstration Project (LSDP) sponsored by the US Department of Energy (DOE), office of Science and Technology (OST), Deactivation and Decommissioning Focus Area (DDFA). The objective of the LSDP is to select and demonstrate potentially beneficial technologies at the Argonne National Laboratory-East (ANL) CP-5 Research Reactor. The purpose of the LSDP is to demonstrate that using innovative and improved decontamination and decommissioning (D and D) technologies from various sources can result in significant benefits, such as decreased cost and increased health and safety, as compared with baseline D and D technologies. Potential markets exist for the innovative centrifugal shot blast system at the following sites: Fernald Environmental Management Project, Los Alamos, Nevada, Oak Ridge Y-12 and K-25, Paducah, Portsmouth Gaseous Diffusion site, and the Savannah River Site. This information is based on a revision to the OST Linkage Tables dated August 4, 1997.

  19. Pre-Combustion Carbon Capture by a Nanoporous, Superhydrophobic Membrane Contactor Process

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Howard; Zhou, S James; Ding, Yong; Bikson, Ben

    2012-03-31

    This report summarizes progress made during Phase I and Phase II of the project: "Pre-Combustion Carbon Capture by a Nanoporous, Superhydrophobic Membrane Contactor Process," under contract DE-FE-0000646. The objective of this project is to develop a practical and cost effective technology for CO{sub 2} separation and capture for pre-combustion coal-based gasification plants using a membrane contactor/solvent absorption process. The goals of this technology development project are to separate and capture at least 90% of the CO{sub 2} from Integrated Gasification Combined Cycle (IGCC) power plants with less than 10% increase in the cost of energy services. Unlike conventional gas separation membranes, the membrane contactor is a novel gas separation process based on the gas/liquid membrane concept. The membrane contactor is an advanced mass transfer device that operates with liquid on one side of the membrane and gas on the other. The membrane contactor can operate with pressures that are almost the same on both sides of the membrane, whereas the gas separation membranes use the differential pressure across the membrane as driving force for separation. The driving force for separation for the membrane contactor process is the chemical potential difference of CO{sub 2} in the gas phase and in the absorption liquid. This process is thus easily tailored to suit the needs for pre-combustion separation and capture of CO{sub 2}. Gas Technology Institute (GTI) and PoroGen Corporation (PGC) have developed a novel hollow fiber membrane technology that is based on chemically and thermally resistant commercial engineered polymer poly(ether ether ketone) or PEEK. The PEEK membrane material used in the membrane contactor during this technology development program is a high temperature engineered plastic that is virtually non-destructible under the operating conditions encountered in typical gas absorption applications. It can withstand contact with most of the common treating

  20. Centrifugal microfluidics for biomedical applications.

    Science.gov (United States)

    Gorkin, Robert; Park, Jiwoon; Siegrist, Jonathan; Amasia, Mary; Lee, Beom Seok; Park, Jong-Myeon; Kim, Jintae; Kim, Hanshin; Madou, Marc; Cho, Yoon-Kyoung

    2010-07-21

    The centrifugal microfluidic platform has been a focus of academic and industrial research efforts for almost 40 years. Primarily targeting biomedical applications, a range of assays have been adapted on the system; however, the platform has found limited commercial success as a research or clinical tool. Nonetheless, new developments in centrifugal microfluidic technologies have the potential to establish wide-spread utilization of the platform. This paper presents an in-depth review of the centrifugal microfluidic platform, while highlighting recent progress in the field and outlining the potential for future applications. An overview of centrifugal microfluidic technologies is presented, including descriptions of advantages of the platform as a microfluidic handling system and the principles behind centrifugal fluidic manipulation. The paper also discusses a history of significant centrifugal microfluidic platform developments with an explanation of the evolution of the platform as it pertains to academia and industry. Lastly, we review the few centrifugal microfluidic-based sample-to-answer analysis systems shown to date and examine the challenges to be tackled before the centrifugal platform can be more broadly accepted as a new diagnostic platform. In particular, fully integrated, easy to operate, inexpensive and accurate microfluidic tools in the area of in vitro nucleic acid diagnostics are discussed.

  1. Unshrouded Centrifugal Turbopump Impeller

    Science.gov (United States)

    Prueger, George; Williams, Morgan; Chen, Wei; Paris, John; Stewart, Eric; Williams, Robert

    1999-01-01

    The ratio of rocket engine thrust to weight is a limiting constraint in placing more payload into orbit at a low cost. A key component of an engine's overall weight is the turbopump weight, Reducing the turbopump weight can result in significant engine weight reduction and hence, increased delivered payload. There are two main types of pumps: centrifugal and axial pumps. These types of pumps can be further sub-divided into those with shrouds and those without shrouds (unshrouded pumps). Centrifugal pumps can achieve the same pump discharge pressure as an axial pump and it requires fewer pump stages and lower pump weight than an axial pump. Also, with unshrouded centrifugal pumps (impeller), the number of stages and weight can be further reduced. However. there are several issues with regard to using an unshrouded impeller: 1) there is a pump performance penalty due to the front open face recirculation flow; 2) there is a potential pump axial thrust problem from the unbalanced front open face and the back shroud face; and, 3) since test data is very linu'ted for this configuration, there is uncertainty in the magnitude and phase of the rotordynamics forces due to the front impeller passage. The purpose of the paper is to discuss the design of an unshrouded impeller and to examine the design's hydrodynamic performance, axial thrust, and rotordynamics performance. The design methodology will also be discussed. This work will help provide some guidelines for unshrouded impeller design. In particular, the paper will discuss the design of three unshrouded impellers - one with 5 full and 5 partial blades (5+5). one with 6+6 blades and one with 8+8 blades. One of these designs will be selected for actual fabrication and flow test. Computational fluid dynamics (CFD) is used to help design and optimize the unshrouded impeller. The relative pump performance penalty is assessed by comparing the CFD results of the unshrouded impeller with the equivalent shrouded impeller for a

  2. A clinical study of annular cyclitis

    Directory of Open Access Journals (Sweden)

    Marilita Michael Moschos

    2009-02-01

    Full Text Available Marilita Michael Moschos1, Yan Guex-Crosier2, Ioannis Margetis1, Leonidas Zografos21Department of Ophthalmology, University of Athens, Greece; 2Jules Gonin Eye Hospital, University of Lausanne, SwitzerlandPurpose: To investigate six cases of annular cyclitis.Methods: All patients with impairment of visual acuity underwent complete ophthalmologic examination, color fundus photography, laboratory tests and fluorescein angiography. Indocyanine green (ICG angiography and B-scan ultrasonography were also performed in three cases in order to diagnose the disease.Results: All patients presented a unilateral or bilateral granulomatous uveitis, associated with inflammatory annular cyclitis. They had a shallow anterior chamber, a mildly elevated intraocular pressure (under 25 mm Hg and an annular serous retinal detachment. A resolution was observed after specific therapy associated with systemic prednisolone therapy and antiglaucomatous drops.Conclusion: This is the first description of an observational study of six patients with inflammatory annular cyclitis.Keywords: cyclitis, uveitis, malignant glaucoma

  3. Divergent Field Annular Ion Engine Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed work investigates an approach that would allow an annular ion engine geometry to achieve ion beam currents approaching the Child-Langmuir limit. In this...

  4. Adaptive optics scanning ophthalmoscopy with annular pupils.

    Science.gov (United States)

    Sulai, Yusufu N; Dubra, Alfredo

    2012-07-01

    Annular apodization of the illumination and/or imaging pupils of an adaptive optics scanning light ophthalmoscope (AOSLO) for improving transverse resolution was evaluated using three different normalized inner radii (0.26, 0.39 and 0.52). In vivo imaging of the human photoreceptor mosaic at 0.5 and 10° from fixation indicates that the use of an annular illumination pupil and a circular imaging pupil provides the most benefit of all configurations when using a one Airy disk diameter pinhole, in agreement with the paraxial confocal microscopy theory. Annular illumination pupils with 0.26 and 0.39 normalized inner radii performed best in terms of the narrowing of the autocorrelation central lobe (between 7 and 12%), and the increase in manual and automated photoreceptor counts (8 to 20% more cones and 11 to 29% more rods). It was observed that the use of annular pupils with large inner radii can result in multi-modal cone photoreceptor intensity profiles. The effect of the annular masks on the average photoreceptor intensity is consistent with the Stiles-Crawford effect (SCE). This indicates that combinations of images of the same photoreceptors with different apodization configurations and/or annular masks can be used to distinguish cones from rods, even when the former have complex multi-modal intensity profiles. In addition to narrowing the point spread function transversally, the use of annular apodizing masks also elongates it axially, a fact that can be used for extending the depth of focus of techniques such as adaptive optics optical coherence tomography (AOOCT). Finally, the positive results from this work suggest that annular pupil apodization could be used in refractive or catadioptric adaptive optics ophthalmoscopes to mitigate undesired back-reflections.

  5. [Galileo and centrifugal force].

    Science.gov (United States)

    Vilain, Christiane

    This work intends to focus on Galileo's study of what is now called "centrifugal force," within the framework of the Second Day of his Dialogo written in 1632, rather than on the previously published commentaries on the topic. Galileo proposes three geometrical demonstrations in order to prove that gravity will always overcome centrifugalforce, and that the potential rotation of the Earth, whatever its speed, cannot in any case project objects beyond it. Each of these demonstrations must consequently contain an error and it has seemed to us that the first one had not been understood up until now. Our analysis offers an opportunity to return to Galileo's geometrical representation of dynamical questions; actually, we get an insight into the sophistication of Galileo's practices more than into his mistakes. Our second point, concerning the historiography of the problem, shows an evolution from anachronic critics to more contextual considerations, in the course of the second half of the twentieth century.

  6. Evaluating hydraulic and disinfection efficiencies of a full-scale ozone contactor using a RANS-based modeling framework.

    Science.gov (United States)

    Zhang, Jie; Tejada-Martínez, Andrés E; Zhang, Qiong; Lei, Hongxia

    2014-04-01

    The capability of predicting hydraulic and disinfection efficiencies of ozone disinfection contactors is essential for evaluating existing contactors and improving future designs. Previous attempts based on ideal and non-ideal models for the hydraulics and simplified mechanisms for chemical reaction modeling have resulted in low accuracy and are restricted to contactors with simple geometries. This manuscript develops a modeling framework for the ozonation process by combining computational fluid dynamics (CFD) with a kinetics-based reaction modeling for the first time. This computational framework has been applied to the full-scale ozone contactor operated by the City of Tampa Water Department. Flow fields, residence time distribution, ozone concentration distribution, and concentration-contact time (CT) distribution within the contactor have been predicted via the computational framework. The predictions of ozone and bromate concentrations at sample points agree well with physical experimental data measured in the contactor. The predicted CT values at the contactor outlet demonstrate that the disinfection performance of the ozone contactor operated by the City of Tampa Water Department is sufficient to meet regulation requirements. The impact of seasonal flow rate change on disinfection performance is found to be significant and deserves attention during the management and operation of a water treatment plant.

  7. Membrane contactor assisted water extraction system for separating hydrogen peroxide from a working solution, and method thereof

    Science.gov (United States)

    Snyder, Seth W.; Lin, Yupo J.; Hestekin' Jamie A.; Henry, Michael P.; Pujado, Peter; Oroskar, Anil; Kulprathipanja, Santi; Randhava, Sarabjit

    2010-09-21

    The present invention relates to a membrane contactor assisted extraction system and method for extracting a single phase species from multi-phase working solutions. More specifically one preferred embodiment of the invention relates to a method and system for membrane contactor assisted water (MCAWE) extraction of hydrogen peroxide (H.sub.2O.sub.2) from a working solution.

  8. Development of a power electronics unit for the Space Station plasma contactor

    Science.gov (United States)

    Hamley, John A.; Hill, Gerald M.; Patterson, Michael J.; Saggio, Joseph, Jr.; Terdan, Fred; Mansell, Justin D.

    1994-02-01

    A hollow cathode plasma contactor has been baselined as a charge control device for the Space Station (SS) to prevent deleterious interactions of coated structural components with the ambient plasma. NASA LeRC Work Package 4 initiated the development of a plasma contactor system comprised of a Power Electronics Unit (PEU), an Expellant Management Unit (EMU), a command and data interface, and a Plasma Contactor Unit (PCU). A breadboard PEU was designed and fabricated. The breadboard PEU contains a cathode heater and discharge power supply, which were required to operate the PCU, a control and auxiliary power converter, an EMU interface, a command and telemetry interface, and a controller. The cathode heater and discharge supplies utilized a push-pull topology with a switching frequency of 20 kHz and pulse-width-modulated (PWM) control. A pulse ignition circuit derived from that used in arcjet power processors was incorporated in the discharge supply for discharge ignition. An 8088 based microcontroller was utilized in the breadboard model to provide a flexible platform for controller development with a simple command/data interface incorporating a direct connection to SS Mulitplexer/Demultiplexer (MDM) analog and digital I/O cards. Incorporating this in the flight model would eliminate the hardware and software overhead associated with a 1553 serial interface. The PEU autonomously operated the plasma contactor based on command inputs and was successfully integrated with a prototype plasma contactor unit demonstrating reliable ignition of the discharge and steady-state operation.

  9. Development of a Power Electronics Unit for the Space Station Plasma Contactor

    Science.gov (United States)

    Hamley, John A.; Hill, Gerald M.; Patterson, Michael J.; Saggio, Joseph, Jr.; Terdan, Fred; Mansell, Justin D.

    1994-01-01

    A hollow cathode plasma contactor has been baselined as a charge control device for the Space Station (SS) to prevent deleterious interactions of coated structural components with the ambient plasma. NASA LeRC Work Package 4 initiated the development of a plasma contactor system comprised of a Power Electronics Unit (PEU), an Expellant Management Unit (EMU), a command and data interface, and a Plasma Contactor Unit (PCU). A breadboard PEU was designed and fabricated. The breadboard PEU contains a cathode heater and discharge power supply, which were required to operate the PCU, a control and auxiliary power converter, an EMU interface, a command and telemetry interface, and a controller. The cathode heater and discharge supplies utilized a push-pull topology with a switching frequency of 20 kHz and pulse-width-modulated (PWM) control. A pulse ignition circuit derived from that used in arcjet power processors was incorporated in the discharge supply for discharge ignition. An 8088 based microcontroller was utilized in the breadboard model to provide a flexible platform for controller development with a simple command/data interface incorporating a direct connection to SS Mulitplexer/Demultiplexer (MDM) analog and digital I/O cards. Incorporating this in the flight model would eliminate the hardware and software overhead associated with a 1553 serial interface. The PEU autonomously operated the plasma contactor based on command inputs and was successfully integrated with a prototype plasma contactor unit demonstrating reliable ignition of the discharge and steady-state operation.

  10. Mass Transfer And Hydraulic Testing Of The V-05 And V-10 Contactors With The Next Generation Solvent

    Energy Technology Data Exchange (ETDEWEB)

    Herman, D. T.; Duignan, M. R.; Williams, M. R.; Peters, T. B.; Poirier, M. R.; Fondeur, F. F.

    2013-07-31

    The Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) facility is actively pursuing the transition from the current BOBCalixC6 based solvent to the Next Generation Solvent (NGS)-MCU solvent. To support this integration of NGS into the MCU facilities, Savannah River Remediation (SRR) requested that Savannah River National Laboratory (SRNL) perform testing of a blend of the NGS (MaxCalix based solvent) with the current solvent (BOBCalixC6 based solvent) for the removal of cesium (Cs) from the liquid salt waste stream. This testing differs from prior testing by utilizing a blend of BOBCalixC6 based solvent and the NGS with the full (0.05 M) concentration of the MaxCalix as well as a new suppressor, tris(3,7dimethyloctyl) guanidine. Single stage tests were conducted using the full size V-05 and V-10 centrifugal contactors installed at SRNL. These tests were designed to determine the mass transfer and hydraulic characteristics with the NGS solvent blended with the projected heel of the BOBCalixC6 based solvent that will exist in MCU at time of transition. The test program evaluated the amount of organic carryover and the droplet size of the organic carryover phases using several analytical methods. Stage efficiency and mass distribution ratios were determined by measuring Cs concentration in the aqueous and organic phases during single contactor testing. The nominal cesium distribution ratio, D(Cs) measured for extraction ranged from 37-60. The data showed greater than 96% stage efficiency for extraction. No significant differences were noted for operations at 4, 8 or 12 gpm aqueous salt simulant feed flow rates. The first scrub test (contact with weak caustic solution) yielded average scrub D(Cs) values of 3.3 to 5.2 and the second scrub test produced an average value of 1.8 to 2.3. For stripping behavior, the “first stage” D Cs) values ranged from 0.04 to 0.08. The efficiency of the low flow (0.27 gpm aqueous) was calculated to be 82.7%. The Spreadsheet

  11. Effect of Sedimentation on Treated Greywater Through Rotating Biological Contactor

    Directory of Open Access Journals (Sweden)

    Ashfaque Ahmed Pathan

    2016-06-01

    Full Text Available The aim of this paper was to study the effect of sedimentation on effluent of a pilot scale Rotating Biological Contactor (RBC. The treated greywater was given three hours sedimentation period and samples were analyzed to observe the effect of sedimentations under variousflow rates. Greywater was separated from the black water and collected in the collection tank and then it was pumped to an overhead tank. This tank supplied a regulated continuous flow of greywater into the RBC chamber at the required flow rate ranging between 0.28 to 1.89 l/min. A pilot scale RBC simulator was developed and placed outside a hall of residence at National Center of Excellence in Analytical Chemistry, Sindh University, Jamshoro. The simulator was operated at the rotational speed of discs of 1.7 rpm. The disks were uneven and textured so as to encourage growth of bacteria on them. These discs were immersed about 40 percent in the greywater.The simulator produced effluent of significant quality and was found efficient in removal of BOD5, COD and TSS as 85%, 68% and 95% respectively.

  12. Modified rotating biological contactor for removal of dichloromethane vapours.

    Science.gov (United States)

    Ravi, R; Philip, Ligy; Swaminathan, T

    2015-01-01

    Bioreactors are used for the treatment of waste gas and odour that has gained much acceptance in the recent years to treat volatile organic compounds (VOCs). The different types of bioreactors (biofilter, biotrickling filter and bioscrubber) have been used for waste gas treatment. Each of these reactors has some advantages and some limitations. Though biodegradation is the main process for the removal of the pollutants, the mechanisms of removal and the microbial communities may differ among these bioreactors. Consequently, their performance or removal efficiency may also be different. Clogging of reactor and pressure drop are the main problems. In this study attempts are made to use the principle of rotating biological contactor (RBC) used for wastewater treatment for the removal of VOC. To overcome the above problem the RBC is modified which is suitable for the treatment of VOC (dichloromethane, DCM). DCM is harmful to human health and hazardous to the atmospheric environment. Modified RBC had no clogging problems and no pressure drop. So, it can handle the pollutant load for a longer period of time. A maximum elimination capacity of 25.7 g/m3 h has been achieved in this study for the DCM inlet load of 58 g/m3 h. The average biofilm thickness is 1 mm. The transient behaviour of the modified RBC treating DCM was investigated. The modified RBC is able to handle shutdown, restart and shock loading operations.

  13. Life Cycle Tests on a Hollow Cathode Based Plasma Contactor

    Science.gov (United States)

    Vaughn, Jason A.; Schneider, Todd A.; Munafo, Paul (Technical Monitor)

    2001-01-01

    The propulsive Small Expendable Deployer System (ProSEDS) mission is designed to provide an on-orbit demonstration of the electrodynamic propulsion capabilities of tethers in space. The ProSEDS experiment will be a secondary payload on a Delta II unmanned expendable booster with a mission duration of 12 days. A 5-km conductive tether is attached to the Delta II second stage and collects current from the low Earth orbit (LEO) plasma, and a Hollow Cathode Plasma Contactor (HCPC) emits the collected electrons from the Delta II, completing the electrical circuit to the ambient plasma. The HCPC for the ProSEDS mission have made it necessary to turn off the HCPC once a minute throughout the entire mission. Because of the unusual operating requirements by the ProSEDS mission, an engineering development unit of the HCPC was built to demonstrate the HCPC design would start reliably for the life of the ProSEDS mission. During the life test the engineering unit cycled for over 10,000 on/off cycles without missing a single start, and during that same test the HCPC unit demonstrated the capability to emit 0 to 5 A electron emission current. The performance of the HCPC unit during this life test will be discussed.

  14. Preliminary Study of Greywater Treatment through Rotating Biological Contactor

    Directory of Open Access Journals (Sweden)

    Ashfaq Ahmed Pathan

    2011-07-01

    Full Text Available The characteristics of the greywater vary from country to country and it depends upon the cultural and social behavior of the respective country. There was a considerable need to characterize and recycle the greywater. In this regard greywater was separated from the black water and analyzed for various physiochemical parameters. Among various greywater recycling treatment technologies, RBC (Rotating Biological Contactor is more effective treatment technique in reducing COD (Chemical Oxygen Demand and organic matters from the greywater. But this technology was not applied and tested in Pakistan. There was extensive need to investigate the RBC technology for greywater recycling at small scale before applying at mass scale. To treat the greywater, a single-stage RBC simulator was designed and developed at laboratory scale. An electric motor equipped with gear box to control the rotations of the disks was mounted on the tank. The simulator was run at the rate of 1.7 rpm. The disc area of the RBC was immersed about 40% in the greywater. Water samples were collected at each HRT (Hydraulic Retention Time and analyzed for the parameters such as pH, conductivity, TDS (Total Dissolved Solids, salinity, BOD5 (Biochemical Oxygen Demand, COD and suspended solids by using standard methods. The results are encouraging with percentage removal of BOD5 and COD being 53 and 60% respectively.

  15. A turbulent bed contactor: energetic efficiency for particle collection

    Directory of Open Access Journals (Sweden)

    M. L. Gimenes

    2007-03-01

    Full Text Available Particle collection experiments were conducted in a fluidizing irrigated bed to evaluate the performance of mobile packings: 38 x 50 mm plain oblate spheroids 38 mm ID plain spheres and alternative perforated spheres with a 38 mm ID and 10% and 25% free areas were used as fluidizing media in a 0.264 m diameter and 1.20 m high turbulent bed contactor (TBC. Particle collection experiments were carried out above the minimum fluidization velocity, using as particulate test powder polysized alumina (size 1.5 to 5.5 mm. Experimental results demonstrated that the perforated spheres performed better in collecting particles than the other packings tested. The efficiency of particle collection was analysed based on energy consumption in the TBC, using the energetic efficiency concept. It was verified that not much more energy was consumed per unit of gas flow in fluidized beds of perforated packings than in those of conventional plain sphere packings, since the perforated spheres were more energetically efficient for particle collection than plain spheres and oblate spheroid packings.

  16. Apparatus for supporting contactors used in extracting nuclear materials from liquids

    Science.gov (United States)

    Leonard, Ralph A.; Frank, Robert C.

    1991-01-01

    Apparatus is provided for supporting one or more contactor stages used to remove radioactive materials from aqueous solutions. The contactor stages include a housing having an internal rotor, a motor secured to the top of the housing for rotating the rotor, and a drain in the bottom of the housing. The support apparatus includes two or more vertical members each secured to a ground support that is horizontal and perpendicular to the frame member, and a horizontally disposed frame member. The frame member may be any suitable shape, but is preferably a rectangular tube having substantially flat, spaced top and bottom surfaces separated by substantially vertical side surfaces. The top and bottom surfaces each have an opening through which the contactor housing is secured so that the motor is above the frame and the drain is below the frame during use.

  17. Application of PTFE membrane for ammonia removal in a membrane contactor.

    Science.gov (United States)

    Ahn, Y T; Hwang, Y H; Shin, H S

    2011-01-01

    The feasibility of a membrane contactor system for ammonia removal was studied. The mass transfer coefficient was used to quantitatively compare the effect of various operation conditions on ammonia removal efficiency. Effective removal of ammonia was possible with a Polytetrafluoroethylene (PTFE) membrane contactor system at all tested conditions. Among the various operation parameters, contact time and solution pH showed significant effect on the ammonia removal mechanism. The overall ammonia removal rate was not affected by influent suspended solution concentration unlike other pressure driven membrane filtration processes. Also the osmotic distillation phenomena which deteriorate the mass transfer efficiency can be minimized by preheating of influent wastewater. A membrane contactor system can be a possible alternative to treat high strength nitrogen wastewater by optimizing operation conditions such as stripping solution flow rate, influent wastewater temperature, and influent pH.

  18. Sediment particle entrainment in an obstructed annular

    Energy Technology Data Exchange (ETDEWEB)

    Loureiro, Bruno Venturini; Siqueira, Renato do Nascimento [Faculdade do Centro Leste (UCL), Serra, ES (Brazil). Lab. de Fenomenos de Transporte], e-mail: brunovl@ucl.br, e-mail: renatons@ucl.br

    2006-07-01

    Flow in an annular region with internal cylinder rotation is a classic problem in fluid mechanics and has been widely studied. Besides its importance as a fundamental problem, flow in annular regions has several practical applications. This project was motivated by an application of this kind of flow to the drilling of oil and gas wells. In this work, an erosion apparatus was constructed in order to study the effect of the internal cylinder rotation on particle entrainment in an obstructed annular space and bed package as well. The study also analyzed the influence of height of the particles bed on the process performance. The experiment was designed so that the internal cylinder rotation could be measured by an encoder. The fluid temperature was measured by a thermocouple and the experiments were carried out at the temperature of 25 deg C. The study revealed that the particle entrainment for the height of the bed that is close to the center of the cylinders is negligible and the internal cylinder rotation provokes the movement and packing of the bed. For lower height of the bed, with same dimension of the annular gap, the particle entrainment process was satisfactory and the bed compaction was smaller than in the previous case, leading to a more efficient cleaning process in the annular space. (author)

  19. Microwave assisted centrifuge and related methods

    Science.gov (United States)

    Meikrantz, David H [Idaho Falls, ID

    2010-08-17

    Centrifuge samples may be exposed to microwave energy to heat the samples during centrifugation and to promote separation of the different components or constituents of the samples using a centrifuge device configured for generating microwave energy and directing the microwave energy at a sample located in the centrifuge.

  20. Development of a WES Centrifuge,

    Science.gov (United States)

    1992-09-01

    centrifuge chamber during a long centrifuge flight ANS&A have suggested that a more practical and economical alternative would be to provide thermal barriers around...specifications and costs can be prepared, as follows; (10) Constant temperature and temperature gradient control system based on thermal barriers both...CONTROL SYSTEM Design study by ANS&A for constant temperature and temperature gradient control system based on thermal barriers both external to and

  1. Hyperbolically Shaped Centrifugal Compressor

    Institute of Scientific and Technical Information of China (English)

    Romuald Puzyrewski; Pawel Flaszy(n)ski

    2003-01-01

    Starting from the classical centrifugal compressor, cone shaped in meridional cross section, two modifications are considered on the basis of results from 2D and 3D flow models. The first modification is the change of the meridional cross section to hyperbolically shaped channel. The second modification, proposed on the basis of 2D axisymmetric solution, concerns the shape of blading. On the strength of this solution the blades are formed as 3D shaped blades, coinciding with the recent tendency in 3D designs. Two aims were considered for the change of meridional compressor shape. The first was to remove the separation zone which appears as the flow tums from axial to radial direction. The second aim is to uniformize the flow at exit of impeller. These two goals were considered within the frame of 2D axisymmetric model. Replacing the cone shaped compressor by a hyperbolically shaped one, the separation at the corner was removed. The disc and shroud shape of the compressor was chosen in the way which satisfies the condition of most uniform flow at the compressor exit. The uniformity of exit flow from the rotor can be considered as the factor which influences the performance of the diffuser following the rotor. In the 2D model a family of stream surfaces of S1 type is given in order to find S2 surfaces which may be identified with the midblade surfaces of compressor blading. A computation of 3D type has been performed in order to establish the relations between 2D and 3D models in the calculation of flow parameters. In the presented example the 2D model appears as the inverse model which leads to 3D shape of blading whereas the 3D model has been used for the direct solution. In the presented example the confrontation of two models, 2D and 3D, leads to a better understanding of the application of these models to the design procedure.

  2. Centrifugation. A theoretical study of oxygen enrichment by centrifugation

    Energy Technology Data Exchange (ETDEWEB)

    Kierkegaard, P.; Raetz, E.

    1998-12-01

    In the present paper we first investigate what happens if we fill a cylinder with air, close it and rotate it. The results show that no matter which peripheral speed is used, it is not possible by means of the radial separation effect alone, to enrich the oxygen concentration from the previous 21% to more then 23.3%, which is of no practical value. In case of a too low enrichment in one centrifuge, the wanted material from this centrifuge can be used as an input for a second centrifuge and so on, in this way forming a cascade of centrifuges. Oxygen will be enriched in each step, until the desired concentration is reached. Cascading was the technology in the very beginning by enrichment plants for uraniumhexaflouride, used for atomic weapons and nuclear power plants. In this study we try to avoid cascading by aiming for higher separation factors. Therefore, we next investigate the possibilities of using a countercurrent centrifuge where in principle the enriched gas is subjected to several centrifugation in the same centrifuge. The calculations show, that in this way it is possible to produce nearly a 100% pure oxygen (polluted with some heavier molecules like argon) in one machine. Our third step was to calculate the amount of oxygen produced per hour. Using a countercurrent centrifuge of the Zippe type, 100 cm high and 20 cm in diameter, it is or will be possible in the near future to produce 17 g enriched air per hour enriched to 50% oxygen. That corresponds to processing 1 m{sup 3} atmospherical air in the period of approximately 24 hours. This is not very impressive. Our fourth step was to estimate the amount of power used for producing this amount of oxygen. A rough, but complicated, estimate shows that the power consumption at the production level will be about the double of the consumption used today. The overall conclusion is, that centrifugation as a production method for oxygen (or nitrogen) will not be competitive with the currently used method in the

  3. Annular, erythematous skin lesions in a neonate

    Directory of Open Access Journals (Sweden)

    Aparna Palit

    2012-01-01

    Full Text Available A 7-day-old premature female infant presented with rapidly progressive, erythematous, annular skin lesions from the 5 th day of life. She was diagnosed provisionally as a case of neonatal lupus erythematosus and was investigated accordingly. Histopathological examination of the skin biopsy specimen revealed presence of hyphae of dermatophytes in the stratum corneum, and the diagnosis was changed to tinea corporis. Differential diagnosis of the annular erythema of infancy has been discussed and the importance of scraping a scaly lesion for KOH preparation in the diagnostic work-up of such a patient has been highlighted.

  4. Stitching algorithm for annular subaperture interferometry

    Institute of Scientific and Technical Information of China (English)

    Xi Hou; Fan Wu; Li Yang; Shibin Wu; Qiang Chen

    2006-01-01

    @@ Annular subaperture interferometry (ASI) has been developed for low cost and flexible test of rotationally symmetric aspheric surfaces, in which accurately combining the subaperture measurement data corrupted by misalignments and noise into a complete surface figure is the key problem. By introducing the Zernike annular polynomials which are orthogonal over annulus, a method that eliminates the coupling problem in the earlier algorithm based on Zernike circle polynomials is proposed. Vector-matrix notation is used to simplify the description and calculations. The performance of this reduction method is evaluated by numerical simulation. The results prove this method with high precision and good anti-noise capability.

  5. Optimal Thrust Vectoring for an Annular Aerospike Nozzle Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Recent success of an annular aerospike flight test by NASA Dryden has prompted keen interest in providing thrust vector capability to the annular aerospike nozzle...

  6. FOULING CHARACTERIZATION OF MEMBRANE CONTACTORS USED FOR THE RECOVERY AND CONCENTRATION OF AMMONIA FROM UNDIGESTED PIG SLURRY

    DEFF Research Database (Denmark)

    Zarebska, Agata; Norddahl, Birgir; Christensen, Knud Villy

    2012-01-01

    The main obstacle impeding implementation of membrane contactors for the recovery and concentration of ammonia from swine manure is the phenomena of membrane fouling. Fouling is defined as the accumulation of suspended or dissolved substances on the membrane surface and/or within its pores. Due...... a week of running the contactor without cleaning. This indicates that fouling could be a severe problem. The intensity of fouling can be reduced by feed pretreatment and by optimizing the operating conditions of the membrane contactor. This will also facilitate removal of ammonia....

  7. 新型交流接触器的应用%Application of New Type of AC Contactor

    Institute of Scientific and Technical Information of China (English)

    刘冬英; 李克芹

    2009-01-01

    简要介绍了TJ40(CJ45)系列新型交流接触器,详细阐述了两种派生产品的用途、结构、特点和应用,即机械联锁可逆交流接触器和切换电容器交流接触器.%The TJ40(CJ45)series new of AC contactors were introduced briefly.The use,structure,trait and application of the two derived contactor products,viz.mechanical interlock reversible AC contactor and smtching capacitor AC eontactor,were expounded.

  8. Centrifuge-Based Fluidic Platforms

    Science.gov (United States)

    Zoval, Jim; Jia, Guangyao; Kido, Horacio; Kim, Jitae; Kim, Nahui; Madou, Marc

    In this chapter centrifuge-based microfluidic platforms are reviewed and compared with other popular microfluidic propulsion methods. The underlying physical principles of centrifugal pumping in microfluidic systems are presented and the various centrifuge fluidic functions such as valving, decanting, calibration, mixing, metering, heating, sample splitting, and separation are introduced. Those fluidic functions have been combined with analytical measurements techniques such as optical imaging, absorbance and fluorescence spectroscopy and mass spectrometry to make the centrifugal platform a powerful solution for medical and clinical diagnostics and high-throughput screening (HTS) in drug discovery. Applications of a compact disc (CD)-based centrifuge platform analyzed in this review include: two-point calibration of an optode-based ion sensor, an automated immunoassay platform, multiple parallel screening assays and cellular-based assays. The use of modified commercial CD drives for high-resolution optical imaging is discussed as well. From a broader perspective, we compare the technical barriers involved in applying microfluidics for sensing and diagnostic as opposed to applying such techniques to HTS. The latter poses less challenges and explains why HTS products based on a CD fluidic platform are already commercially available, while we might have to wait longer to see commercial CD-based diagnostics.

  9. Modelling of cross-flow membrane contactors : Physical mass transfer processes

    NARCIS (Netherlands)

    Dindore, V. Y.; Brilman, D. W. F.; Versteeg, G. F.

    2005-01-01

    Traditionally, hollow fiber membrane contactors used for gas-liquid contacting were designed in a shell and tube configuration with shell-side fluid flowing parallel to the fiber-side fluid, either in co-current or counter-current pattern. The primary limitations of these so-called 'parallel flow' c

  10. Using 3D LIF to Investigate and Improve Performance of a Multichamber Ozone Contactor

    Science.gov (United States)

    Three-dimensional laser-induced fluorescence (3DLIF) was applied to visualize and quantitatively analyze hydrodynamics and mixing in a multi-chamber ozone contactor, the most widely used design for water disinfection. The results suggested that the mixing was characterized by ext...

  11. Modelling of cross-flow membrane contactors: physical mass transfer processes

    NARCIS (Netherlands)

    Dindore, V.Y.; Brilman, D.W.F.; Versteeg, G.F.

    2005-01-01

    Traditionally, hollow fiber membrane contactors used for gas–liquid contacting were designed in a shell and tube configuration with shell-side fluid flowing parallel to the fiber-side fluid, either in co-current or counter-current pattern. The primary limitations of these so-called ‘parallel flow’ c

  12. Surface-Roughness-Based Virtual Textiles: Evaluation Using a Multi-Contactor Display.

    Science.gov (United States)

    Philpott, Matthew; Summers, Ian R

    2015-01-01

    Virtual textiles, generated in response to exploratory movements, are presented to the fingertip via a 24-contactor vibrotactile array. Software models are based on surface-roughness profiles from real textiles. Results suggest that distinguishable "textile-like" surfaces are produced, but these lack the necessary accuracy for reliable matching to real textiles.

  13. Axial liquid mixing in a gas-liquid Multi-Stage Agitated Contactor (MAC)

    NARCIS (Netherlands)

    Breman, B.B; Beenackers, A.A C M; Bouma, M.J; VanderWerf, M.H.

    1996-01-01

    Data on interstage liquid mixing are reported for a gas-liquid Multi-stage Agitated Contactor (MAC). A dynamic method using heat as a tracer was applied for water, n-octane and monoethylene glycol as liquids both with and without the presence of a dispersed gas phase (air). In all cases, the axial m

  14. Treatment of anaerobically pre-treated domestic sewage by a rotating biological contactor

    NARCIS (Netherlands)

    Tawfik, A.; Klapwijk, A.; el-Gohary, F.; Lettinga, G.

    2002-01-01

    The performance of a rotating biological contactor (RBC) for the post-treatment of the effluent of an up-flow anaerobic sludge blanket (UASB) was the subject of this study. Different hydraulic and organic loading rates have been investigated. The removal efficiencies of CODtotal, CODsuspended, CODco

  15. Validation of a simple method for predicting the disinfection performance in a flow-through contactor.

    Science.gov (United States)

    Pfeiffer, Valentin; Barbeau, Benoit

    2014-02-01

    Despite its shortcomings, the T10 method introduced by the United States Environmental Protection Agency (USEPA) in 1989 is currently the method most frequently used in North America to calculate disinfection performance. Other methods (e.g., the Integrated Disinfection Design Framework, IDDF) have been advanced as replacements, and more recently, the USEPA suggested the Extended T10 and Extended CSTR (Continuous Stirred-Tank Reactor) methods to improve the inactivation calculations within ozone contactors. To develop a method that fully considers the hydraulic behavior of the contactor, two models (Plug Flow with Dispersion and N-CSTR) were successfully fitted with five tracer tests results derived from four Water Treatment Plants and a pilot-scale contactor. A new method based on the N-CSTR model was defined as the Partially Segregated (Pseg) method. The predictions from all the methods mentioned were compared under conditions of poor and good hydraulic performance, low and high disinfectant decay, and different levels of inactivation. These methods were also compared with experimental results from a chlorine pilot-scale contactor used for Escherichia coli inactivation. The T10 and Extended T10 methods led to large over- and under-estimations. The Segregated Flow Analysis (used in the IDDF) also considerably overestimated the inactivation under high disinfectant decay. Only the Extended CSTR and Pseg methods produced realistic and conservative predictions in all cases. Finally, a simple implementation procedure of the Pseg method was suggested for calculation of disinfection performance.

  16. Fluxon Dynamics in Elliptic Annular Josephson Junctions

    DEFF Research Database (Denmark)

    Monaco, Roberto; Mygind, Jesper

    2016-01-01

    We analyze the dynamics of a magnetic flux quantum (current vortex) trapped in a current-biased long planar elliptic annular Josephson tunnel junction. The system is modeled by a perturbed sine-Gordon equation that determines the spatial and temporal behavior of the phase difference across the tu...

  17. Annular beam with segmented phase gradients

    Directory of Open Access Journals (Sweden)

    Shubo Cheng

    2016-08-01

    Full Text Available An annular beam with a single uniform-intensity ring and multiple segments of phase gradients is proposed in this paper. Different from the conventional superposed vortices, such as the modulated optical vortices and the collinear superposition of multiple orbital angular momentum modes, the designed annular beam has a doughnut intensity distribution whose radius is independent of the phase distribution of the beam in the imaging plane. The phase distribution along the circumference of the doughnut beam can be segmented with different phase gradients. Similar to a vortex beam, the annular beam can also exert torques and rotate a trapped particle owing to the orbital angular momentum of the beam. As the beam possesses different phase gradients, the rotation velocity of the trapped particle can be varied along the circumference. The simulation and experimental results show that an annular beam with three segments of different phase gradients can rotate particles with controlled velocities. The beam has potential applications in optical trapping and optical information processing.

  18. A New Annular Shear Piezoelectric Accelerometer

    DEFF Research Database (Denmark)

    Liu, Bin; Kriegbaum, B.

    2000-01-01

    This paper describes the construction and performance of a recently introduced Annular Shear piezoelectric accelerometer, Type 4511. The design has insulated and double-shielded case. The accelerometer housing is made of stainless steel, AISI 316L. Piezoceramic PZ23 is used. The seismic mass...

  19. Annular lichenoid syphilis: A rare entity.

    Science.gov (United States)

    Khurana, Ananta; Singal, Archana; Gupta, Seema

    2014-01-01

    Syphilis is a disease known for centuries, but still continues to be a diagnostic challenge as the myriad manifestations of secondary syphilis can mimic a lot many dermatological disorders. Lichenoid syphilis is an uncommon entity, reported only occasionally in the penicillin era. We present the case of a 32-year-old woman presenting with localized annular lichenoid lesions on the neck.

  20. Annular Pressure Seals and Hydrostatic Bearings

    Science.gov (United States)

    2006-11-01

    affecting the rotordynamics of liquid turbopumps, in particular those handling large density fluids. Highlights on the bulk-flow analysis of annular seals... rotordynamic stability. Hydrostatic bearings rely on external fluid pressurization to generate load support and large centering stiffnesses, even in...SEALS IN PUMP APPLICATIONS Seal rotordynamic characteristic have a primary influence on the stability response of high-performance turbomachinery [1

  1. MEANS FOR DETERMINING CENTRIFUGE ALIGNMENT

    Science.gov (United States)

    Smith, W.Q.

    1958-08-26

    An apparatus is presented for remotely determining the alignment of a centrifuge. The centrifage shaft is provided with a shoulder, upon which two followers ride, one for detecting radial movements, and one upon the shoulder face for determining the axial motion. The followers are attached to separate liquid filled bellows, and a tube connects each bellows to its respective indicating gage at a remote location. Vibrations produced by misalignment of the centrifuge shaft are transmitted to the bellows, and tbence through the tubing to the indicator gage. This apparatus is particularly useful for operation in a hot cell where the materials handled are dangerous to the operating personnel.

  2. Generalized anti-centrifugal potential

    Energy Technology Data Exchange (ETDEWEB)

    Dandoloff, Rossen [Laboratoire de Physique Theorique et Modelisation, Universite de Cergy-Pontoise, F-95302 Cergy-Pontoise (France); Jensen, Bjørn [Department of Micro and Nano Systems Technology, Vestfold University College, N-3103 Tønsberg (Norway); Saxena, Avadh, E-mail: avadh@lanl.gov [Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2014-01-24

    We generalize the quantum anti-centrifugal potential in the two-dimensional Euclidean plane to two-dimensional surfaces embedded in three-dimensional Euclidean space. We consider the sphere with two caps removed in some detail. We show that quantum particles in this space are “pushed” towards either of the cap boundaries. We also consider the two-dimensional Euclidean plane with an elliptic area removed and compute the quantum anti-centrifugal potential on the elliptic boundary. It is argued that a sufficiently thin electrically conducting nano-wire shaped as an ellipse will exhibit an inhomogeneous charge distribution due to this quantum potential.

  3. Mass Transfer And Hydraulic Testing Of The V-05 And V-10 Contactors With The Next Generation Solvent

    Energy Technology Data Exchange (ETDEWEB)

    Herman, D. T.; Duignan, M. R.; Williams, M. R.; Peters, T. B.; Poirier, M. R.; Fondeur, F. F.

    2013-07-31

    The Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) facility is actively pursuing the transition from the current BOBCalixC6 based solvent to the Next Generation Solvent (NGS)-MCU solvent. To support this integration of NGS into the MCU facilities, Savannah River Remediation (SRR) requested that Savannah River National Laboratory (SRNL) perform testing of a blend of the NGS (MaxCalix based solvent) with the current solvent (BOBCalixC6 based solvent) for the removal of cesium (Cs) from the liquid salt waste stream. This testing differs from prior testing by utilizing a blend of BOBCalixC6 based solvent and the NGS with the full (0.05 M) concentration of the MaxCalix as well as a new suppressor, tris(3,7dimethyloctyl) guanidine. Single stage tests were conducted using the full size V-05 and V-10 centrifugal contactors installed at SRNL. These tests were designed to determine the mass transfer and hydraulic characteristics with the NGS solvent blended with the projected heel of the BOBCalixC6 based solvent that will exist in MCU at time of transition. The test program evaluated the amount of organic carryover and the droplet size of the organic carryover phases using several analytical methods. Stage efficiency and mass distribution ratios were determined by measuring Cs concentration in the aqueous and organic phases during single contactor testing. The nominal cesium distribution ratio, D(Cs) measured for extraction ranged from 37-60. The data showed greater than 96% stage efficiency for extraction. No significant differences were noted for operations at 4, 8 or 12 gpm aqueous salt simulant feed flow rates. The first scrub test (contact with weak caustic solution) yielded average scrub D(Cs) values of 3.3 to 5.2 and the second scrub test produced an average value of 1.8 to 2.3. For stripping behavior, the “first stage” D Cs) values ranged from 0.04 to 0.08. The efficiency of the low flow (0.27 gpm aqueous) was calculated to be 82.7%. The Spreadsheet

  4. Theory of batchwise centrifugal casting

    NARCIS (Netherlands)

    Biesheuvel, P. Maarten; Nijmeijer, Arian; Verweij, Henk

    1998-01-01

    In batchwise centrifugal casting a cylindrical mold is filled with suspension and rotated rapidly around its axis. This results in the movement of the particulate phase toward the cylinder wall and the formation of a tubular cast. Theory is presented for particle transport in the suspension phase an

  5. CENTRIFUGAL CASTING OF ANTIFRICTION SILUMIN

    Directory of Open Access Journals (Sweden)

    V. Ju. Stetsenko

    2010-01-01

    Full Text Available It is shown that the way of centrifugal casting into water-cooled mould with vertical rotation axis enables to receive hollow slugs with diameter 100–250 mm, with height under 200 mm with wall thickness under 15 mm of antifriction silumin АК15М3, which will replace expensive antifriction bronze.

  6. Simulation studies of ammonia removal from water in a membrane contactor under liquid-liquid extraction mode.

    Science.gov (United States)

    Mandowara, Amish; Bhattacharya, Prashant K

    2011-01-01

    Simulation studies were carried out, in an unsteady state, for the removal of ammonia from water via a membrane contactor. The contactor had an aqueous solution of NH(3) in the lumen and sulphuric acid in the shell side. The model equations were developed considering radial and axial diffusion and convection in the lumen. The partial differential equations were converted by the finite difference technique into a series of stiff ordinary differential equations w.r.t. time and solved using MATLAB. Excellent agreement was observed between the simulation results and experimental data (from the literature) for a contactor of 75 fibres. Excellent agreement was also observed between the simulation results and laboratory-generated data from a contactor containing 10,200 fibres. Our model is more suitable than the plug-flow model for designing the operation of the membrane contactor. The plug-flow model over-predicts the fractional removal of ammonia and was observed to be limited when designing longer contactors.

  7. Non newtonian annular alloy solidification in mould

    Energy Technology Data Exchange (ETDEWEB)

    Moraga, Nelson O.; Garrido, Carlos P. [Universidad de La Serena, Departamento de Ingenieria Mecanica, La Serena (Chile); Castillo, Ernesto F. [Universidad de Santiago de Chile, Departamento de Ingenieria Mecanica, Santiago (Chile)

    2012-08-15

    The annular solidification of an aluminium-silicon alloy in a graphite mould with a geometry consisting of horizontal concentric cylinders is studied numerically. The analysis incorporates the behavior of non-Newtonian, pseudoplastic (n=0.2), Newtonian (n=1), and dilatant (n=1.5) fluids. The fluid mechanics and heat transfer coupled with a transient model of convection diffusion are solved using the finite volume method and the SIMPLE algorithm. Solidification is described in terms of a liquid fraction of a phase change that varies linearly with temperature. The final results make it possible to infer that the fluid dynamics and heat transfer of solidification in an annular geometry are affected by the non-Newtonian nature of the fluid, speeding up the process when the fluid is pseudoplastic. (orig.)

  8. Dynamics of bouncing droplets in annular cavities

    Science.gov (United States)

    Lentz, Zachary Louis; Jalali, Mir Abbas; Alam, Mohammad-Reza

    2014-11-01

    In a cylindrical bath of silicon oil, vertically excited by a frequency of 45 Hz, we trace the motion of bouncing droplets as they fill an annular region. We compute the mean tangential and radial velocity components of the droplets and show that the maximum tangential velocity is larger than the maximum radial velocity by one order of magnitude. Velocity dispersions have almost equal levels in the radial and tangential directions, and their mean values are 1/4 times smaller than the mean tangential velocity. These results show that bouncing droplets undergo random motions within annular cavities determined by the interference patterns of self-induced circumferential waves. We derive analytical relations between the velocity dispersion and the wavelength of surface waves, and calculate the mean tangential velocity of droplets using the random kicks that they experience at the boundaries of the cavity by inward and outward traveling waves.

  9. Annular and Total Solar Eclipses of 2003

    Science.gov (United States)

    Espenak, Fred; Anderson, Jay

    2002-01-01

    On Saturday, 2003 May 31, an annular eclipse of the Sun will be visible from a broad corridor that traverses the North Atlantic. The path of the Moon's antumbral shadow begins in northern Scotland, crosses Iceland and central Greenland, and ends at sunrise in Baffin Bay (Canada). A partial eclipse will be seen within the much broader path of the Moon's penumbral shadow, which includes most of Europe, the Middle East, central and northern Asia, and northwestern North America. The trajectory of the Moon's shadow is quite unusual during this event. The shadow axis passes to the far north where it barely grazes Earth's surface. In fact, the northern edge of the antumbra actually misses Earth so that one path limit is defined by the day/night terminator rather than by the shadow's upper edge. As a result, the track of annularity has a peculiar "D" shape that is nearly 1200 kilometers wide. Since the eclipse occurs just three weeks prior to the northern summer solstice, Earth's northern axis is pointed sunwards by 22.8 deg. As seen from the Sun, the antumbral shadow actually passes between the North Pole and the terminator. As a consequence of this extraordinary geometry, the path of annularity runs from east to west rather than the more typical west to east. The event transpires near the Moon's ascending node in Taurus five degrees north of Aldebaran. Since apogee occurs three days earlier (May 28 at 13 UT), the Moon's apparent diameter (29.6 arc-minutes) is still too small to completely cover the Sun (31.6 arc-minutes) resulting in an annular eclipse.

  10. Design of a centrifugal blood pump: Heart Turcica Centrifugal.

    Science.gov (United States)

    Demir, Onur; Biyikli, Emre; Lazoglu, Ismail; Kucukaksu, Suha

    2011-07-01

    A prototype of a new implantable centrifugal blood pump system named Heart Turcica Centrifugal (HTC) was developed as a left ventricular assist device (LVAD) for the treatment of end-stage cardiac failure. In the development of HTC, effects of blade height and volute tongue profiles on the hydraulic and hemolytic performances of the pump were investigated. As a result, the prototype was manufactured using the best blade height and volute tongue profiles. Performance of the prototype model was experimentally evaluated in a closed-loop flow system using water as the medium. The hydraulic performance requirement of an LVAD (5 L/min flow rate against a pressure difference of 100 mm Hg) was attained at 2800 rpm rotational speed.

  11. Centrifugal separator devices, systems and related methods

    Science.gov (United States)

    Meikrantz, David H.; Law, Jack D.; Garn, Troy G.; Todd, Terry A.; Macaluso, Lawrence L.

    2012-03-20

    Centrifugal separator devices, systems and related methods are described. More particularly, fluid transfer connections for a centrifugal separator system having support assemblies with a movable member coupled to a connection tube and coupled to a fixed member, such that the movable member is constrained to movement along a fixed path relative to the fixed member are described. Also, centrifugal separator systems including such fluid transfer connections are described. Additionally, methods of installing, removing and/or replacing centrifugal separators from centrifugal separator systems are described.

  12. EFFECT OF ORGANIC LOADING RATES FOR TREATING GREY WATER IN ROTATING BIOLOGICAL CONTACTORS

    Directory of Open Access Journals (Sweden)

    S. Syed Enayathali

    2012-05-01

    Full Text Available The laboratory model of two-stage Rotating Biological Contactor (RBC which was used in the present study is a modified one, with a rovision to vary the speed of rotating blades. Grey wastewater was used to study the performance of the modified rotating biological contactor. The reactor had four rotating blades in each stage, having the size of 300 mm x100 mm x 10 mm, attached perpendicular to the shaft. The experiment was conducted for different influent COD loads and different speeds of rotating blades. Among the different speedsof rotational blades in treating grey water, the rotational speed of 3 rpm was found to yield better percent removal of COD at 95.07% as maximum, where as against the rotational speeds of 4.5 and 6 rpm, the treatment efficiency is 95.04% and 94.96% respectively

  13. An air-liquid contactor for large-scale capture of CO2 from air.

    Science.gov (United States)

    Holmes, Geoffrey; Keith, David W

    2012-09-13

    We present a conceptually simple method for optimizing the design of a gas-liquid contactor for capture of carbon dioxide from ambient air, or 'air capture'. We apply the method to a slab geometry contactor that uses components, design and fabrication methods derived from cooling towers. We use mass transfer data appropriate for capture using a strong NaOH solution, combined with engineering and cost data derived from engineering studies performed by Carbon Engineering Ltd, and find that the total costs for air contacting alone-no regeneration-can be of the order of $60 per tonne CO(2). We analyse the reasons why our cost estimate diverges from that of other recent reports and conclude that the divergence arises from fundamental design choices rather than from differences in costing methodology. Finally, we review the technology risks and conclude that they can be readily addressed by prototype testing.

  14. Effect of Annular Slit Geometry on Characteristics of Spiral Jet

    Institute of Scientific and Technical Information of China (English)

    Shigeru Matsuo; Kwon-Hee Lee; Shinsuke Oda; Toshiaki Setoguchi; Heuy-Dong Kim

    2003-01-01

    A spiral flow using an annular slit connected to a conical cylinder does not need special device to generate a tangential velocity component of the flow and differs from swirling flows. Pressurized fluid is supplied to an annular chamber and injected into the convergent nozzle through the annular slit. The annular jet develops into the spiral flow. In the present study, a spiral jet discharged out of nozzle exit was obtained by using a convergent nozzle and an annular slit set in nozzle inlet, and the effect of annular slit geometry on characteristics of the spiral jet was investigated by using a Laser Doppler Velocimeter (LDV) experimentally. Furthermore, velocity distributions of the spiral jet were compared with those of a normal jet.

  15. Centrifugal pumps and allied machinery

    CERN Document Server

    Anderson, HH

    1994-01-01

    This book will be of vital interest to all engineers and designers concerned with centrifugal pumps and turbines. Including statistical information derived from 20000 pumps and 700 turbines with capacities of 5gpm to 5000000gpm, this book offers the widest range and scope of information currently available. Statistical analyses suggest practical methods of increasing pump performance and provide valuable data for new design aspects.

  16. Liposome and niosome preparation using a membrane contactor for scale-up.

    Science.gov (United States)

    Pham, Thi Thuy; Jaafar-Maalej, Chiraz; Charcosset, Catherine; Fessi, Hatem

    2012-06-01

    The scaling-up ability of liposome and niosome production, from laboratory scale using a syringe-pump device to a pilot scale using the membrane contactor module, was investigated. For this aim, an ethanol injection-based method was applied for liposome and niosome preparation. The syringe-pump device was used for laboratory scale batches production (30 ml for liposomes, 20 ml for niosomes) then a pilot scale (750 ml for liposomes, 1000 ml for niosomes) were obtained using the SPG membrane contactor. Resulted nanovesicles were characterized in terms of mean vesicles size, polydispersity index (PdI) and zeta potential. The drug encapsulation efficiency (E.E.%) was evaluated using two drug-models: caffeine and spironolactone, a hydrophilic and a lipophilic molecule, respectively. As results, nanovectors mean size using the syringe-pump device was comprised between 82 nm and 95 nm for liposomes and between 83 nm and 127 nm for niosomes. The optimal E.E. of caffeine within niosomes, was found around 9.7% whereas the spironolactone E.E. reached 95.6% which may be attributed to its lipophilic properties. For liposomes these values were about 9.7% and 86.4%, respectively. It can be clearly seen that the spironolactone E.E. was slightly higher within niosomes than liposomes. Optimized formulations, which offered smaller size and higher E.E., were selected for pilot scale production using the SPG membrane. It has been found that vesicles characteristics (size and E.E.%) were reproducible using the membrane contactor module. Thus, the current study demonstrated the usefulness of the membrane contactor as a device for scaling-up both liposome and niosome preparations with small mean sizes.

  17. Method of reliability tolerance design based on EDA technology and its application on DC hybrid contactor

    Institute of Scientific and Technical Information of China (English)

    WANG Shu-juan; SHA You-tao; ZHANG Hui; ZHAI Guo-fu

    2007-01-01

    Tolerance design, including tolerance analysis and distribution, is an important part of the electronic system's reliability design. The traditional design needs to construct mathematic model of material circuit, which involves large amount of workload and lacks of practicability. This paper discusses the basic theory of electronic system's reliability tolerance design and presents a new design method based on EDA (Electronic Design Automatic) software. This method has been validated through the application research on reliability tolerance design of the DC hybrid contactor's control circuit.

  18. Preparation and Optimization of a Membrane for 3rd Generation Solvent Membrane Contactor

    OpenAIRE

    Arif, Asad

    2016-01-01

    Third generation solvent is a new class of CO2 absorbents with a great potential in terms of reduction of the regeneration energy requirement for post combustion carbon capture, but their use at the industrial scale is limited by their high volatility. Membrane contactor technology is proposed as possible solution, but the membrane layer must be purposely designed in order to act as amine barrier, without negatively affecting the overall CO2 mass transfer resistance. Teflon AF2400 has been re...

  19. Limited Diffraction Maps for Pulsed Wave Annular Arrays

    DEFF Research Database (Denmark)

    Fox, Paul D.

    2002-01-01

    A procedure is provided for decomposing the linear field of flat pulsed wave annular arrays into an equivalent set of known limited diffraction Bessel beams. Each Bessel beam propagates with known characteristics, enabling good insight into the propagation of annular fields to be obtained....... Numerical examples are given in the context of a 10-ring annular array operating at a central frequency of 2.5 MHz in water....

  20. Limited Diffraction Maps for Pulsed Wave Annular Arrays

    OpenAIRE

    Fox, Paul D.

    2002-01-01

    A procedure is provided for decomposing the linear field of flat pulsed wave annular arrays into an equivalent set of known limited diffraction Bessel beams. Each Bessel beam propagates with known characteristics, enabling good insight into the propagation of annular fields to be obtained. Numerical examples are given in the context of a 10-ring annular array operating at a central frequency of 2.5 MHz in water.

  1. Triple-bore hollow fiber membrane contactor for liquid desiccant based air dehumidification

    KAUST Repository

    Bettahalli, N.M. Srivatsa

    2016-04-26

    Dehumidification is responsible for a large part of the energy consumption in cooling systems in high humidity environments worldwide. Improving efficiency is therefore essential. Liquid desiccants offer a promising solution for dehumidification, as desired levels of humidity removal could be easily regulated. The use of membrane contactors in combination with liquid desiccant is attractive for dehumidification because they prevent direct contact between the humid air and the desiccant, removing both the potential for desiccant carryover to the air and the potential for contamination of the liquid desiccant by dust and other airborne materials, as well as minimizing corrosion. However, the expected additional mass transport barrier of the membrane surface can lower the expected desiccation rate per unit of desiccant surface area. In this context, hollow fiber membranes present an attractive option for membrane liquid desiccant contactors because of their high surface area per unit volume. We demonstrate in this work the performance of polyvinylidene fluoride (PVDF) based triple-bore hollow fiber membranes as liquid desiccant contactors, which are permeable to water vapor but impermeable to liquid water, for dehumidification of hot and humid air.

  2. Extraction and quantification of SO2 content in wines using a hollow fiber contactor.

    Science.gov (United States)

    Plaza, Andrea; Romero, Julio; Silva, Wladimir; Morales, Elizabeth; Torres, Alejandra; Aguirre, María J

    2014-10-01

    Sulfites [Formula: see text] or sulfur dioxide (SO2) is a preservative widely used in fruits and fruit-derived products. This study aims to propose a membrane contactor process for the selective removal and recovery of SO2 from wines in order to obtain its reliable quantification. Currently, the aspiration and Ripper methods offer a difficult quantification of the sulfite content in red wines because they involve evaporation steps of diluted compounds and a colorimetric assay, respectively. Therefore, an inexpensive and accurate methodology is not currently available for continuous monitoring of SO2 in the liquids food industry. Red wine initially acidified at pH Contactor, which separates the acidified red wine in the shell side and a diluted aqueous sodium hydroxide solution as receiving solution into the lumenside in countercurrent. Sulfite and bisulfite in the acidified red wine become molecular SO2, which is evaporated through the membrane pores filled with gas. Thus, SO2 is trapped in a colorless solution and the membrane contactor controls its transfer, decreasing experimental error induced in classical methods. Experimental results using model solutions with known concentration values of [Formula: see text] show an average extraction percentage of 98.91 after 4 min. On the other hand, two types of Chilean Cabernet Sauvignon wines were analyzed with the same system to quantify the content of free and total sulfites. Results show a good agreement between these methods and the proposed technique, which shows a lower experimental variability.

  3. THC1系列交流接触器%THC1 Series AC Contactor

    Institute of Scientific and Technical Information of China (English)

    夏芳娟; 曾萍; 陈红; 陈晓军

    2009-01-01

    介绍了THC1系列交流接触器.从技术参数、结构特点、创新点及材料方面介绍了该接触器的主要特征.新产品采用热塑件以利环保,采用塑料卡扣拼装和端子罩盖便于装配,将原有限的空间分割出若十小室,互不干扰,保证了工作时期的可靠绝缘及安全.%The THC1 AC contactor was introduced.The main traits of this contactor,such as technology,structure point,innovation points and material,were introduced.Thermal plastic was adopted to protect environ-ment.Plastic block buckle and terminal cover were adopted to assemble conveniently.Primary finite space was di-vided into several small cells so that they didn't interfere each other,with ensuring reliable insulation and safety when contactor works.

  4. Arcuate, annular, and polycyclic inflammatory and infectious lesions.

    Science.gov (United States)

    Sharma, Amit; Lambert, Phelps J; Maghari, Amin; Lambert, W Clark

    2011-01-01

    Common shapes encountered in dermatologic diseases include linear, nummular, annular, polycyclic, and arciform. The last three have a relatively restricted differential, which must be entirely explored. It is not uncommon for a single disease to present in annular, arciform or polycyclic configurations; moreover, the lesions may evolve from being arciform to annular and then become polycyclic. Regardless, recognizing the arrangement of the defect will undoubtedly help in making a diagnosis and guiding subsequent management. We explore diseases that often present in annular, arciform, and/or polycyclic forms.

  5. Granuloma annulare localized to the shaft of the penis

    DEFF Research Database (Denmark)

    Trap, R; Wiebe, B

    1993-01-01

    A case of granuloma annulare localized to the shaft of the penis is reported. The differential diagnoses are discussed. Penile granuloma annulare is a rare disorder and it is concluded that biopsies of penile lesions are recommended to verify the correct diagnosis.......A case of granuloma annulare localized to the shaft of the penis is reported. The differential diagnoses are discussed. Penile granuloma annulare is a rare disorder and it is concluded that biopsies of penile lesions are recommended to verify the correct diagnosis....

  6. Finite stretching of an annular plate.

    Science.gov (United States)

    Biricikoglu, V.; Kalnins, A.

    1971-01-01

    The problem of the finite stretching of an annular plate which is bonded to a rigid inclusion at its inner edge is considered. The material is assumed to be isotropic and incompressible with a Mooney-type constitutive law. It is shown that the inclusion of the effect of the transverse normal strain leads to a rapid variation in thickness which is confined to a narrow edge zone. The explicit solutions to the boundary layer equations, which govern the behavior of the plate near the edges, are presented.

  7. Annular lupus vulgaris mimicking tinea cruris.

    Science.gov (United States)

    Heo, Young Soo; Shin, Won Woong; Kim, Yong Ju; Song, Hae Jun; Oh, Chil Hwan

    2010-05-01

    Cutaneous tuberculosis is an infrequent form of extrapulmonary tuberculosis. It is often clinically and histopathologically confused with various cutaneous disorders. A 36-year-old man attended our clinic with slowly progressive, asymptomatic, annular skin lesions on both the thighs and buttocks for 10 years. He consulted with many physicians and was improperly treated with an oral antifungal agent for several months under the diagnosis of tinea cruris, but no resolution of his condition was observed. A diagnosis of lupus vulgaris was made based on the histopathologic examination and the polymerase chain reaction assay. Anti-tuberculosis therapy was administered and the lesions started to regress.

  8. Wave turbulence in annular wave tank

    Science.gov (United States)

    Onorato, Miguel; Stramignoni, Ettore

    2014-05-01

    We perform experiments in an annular wind wave tank at the Dipartimento di Fisica, Universita' di Torino. The external diameter of the tank is 5 meters while the internal one is 1 meter. The tank is equipped by two air fans which can lead to a wind of maximum 5 m/s. The present set up is capable of studying the generation of waves and the development of wind wave spectra for large duration. We have performed different tests including different wind speeds. For large wind speed we observe the formation of spectra consistent with Kolmogorv-Zakharov predictions.

  9. Annular and semicircular lipoatrophies. Report of three cases and review of the literature.

    Science.gov (United States)

    Rongioletti, F; Rebora, A

    1989-03-01

    Two cases of semicircular lipoatrophy and one of annular lipoatrophy are presented. The reasons why semicircular lipoatrophy, annular lipoatrophy, and annular atrophy of the ankles seem to be different clinical entities are discussed.

  10. Centrifuge facilities at Technical University of Denmark

    DEFF Research Database (Denmark)

    Leth, Caspar Thrane; Krogsbøll, Anette Susanne; Hededal, Ole

    2008-01-01

    The geotechnical group at the Danish Technical University (DTU) operates a geotechnical beam centrifuge. The centrifuge was build in 1976 and has been upgraded through the years, latest with onboard data and control systems. The centrifuge concept involves an increased gravity field in which...... the physical model is placed and tested. The capabilities of the centrifuge at DTU makes it possible to obtain a scale factor of 75-85 in the tests which equals a soil volume in prototype scale of ø40m and a depth of 36 m. The centrifuge facilities at DTU have through the years been used for testing various...... geotechnical issues, such as suction anchors, tension piles in clay, active earth pressures on sheet piles and group effects for lateral loaded piles. The paper describes physical modelling in general, the centrifuge, present setups and shows samples of obtained results....

  11. Empirical Design Considerations for Industrial Centrifugal Compressors

    Directory of Open Access Journals (Sweden)

    Cheng Xu

    2012-01-01

    Full Text Available Computational Fluid Dynamics (CFD has been extensively used in centrifugal compressor design. CFD provides further optimisation opportunities for the compressor design rather than designing the centrifugal compressor. The experience-based design process still plays an important role for new compressor developments. The wide variety of design subjects represents a very complex design world for centrifugal compressor designers. Therefore, some basic information for centrifugal design is still very important. The impeller is the key part of the centrifugal stage. Designing a highly efficiency impeller with a wide operation range can ensure overall stage design success. This paper provides some empirical information for designing industrial centrifugal compressors with a focus on the impeller. A ported shroud compressor basic design guideline is also discussed for improving the compressor range.

  12. Centrifugal quantum states of neutrons

    Science.gov (United States)

    Nesvizhevsky, V. V.; Petukhov, A. K.; Protasov, K. V.; Voronin, A. Yu.

    2008-09-01

    We propose a method for observation of the quasistationary states of neutrons localized near a curved mirror surface. The bounding effective well is formed by the centrifugal potential and the mirror Fermi potential. This phenomenon is an example of an exactly solvable “quantum bouncer” problem that can be studied experimentally. It could provide a promising tool for studying fundamental neutron-matter interactions, as well as quantum neutron optics and surface physics effects. We develop a formalism that describes quantitatively the neutron motion near the mirror surface. The effects of mirror roughness are taken into account.

  13. Signatures of an annular Fermi sea

    Science.gov (United States)

    Jo, Insun; Liu, Yang; Pfeiffer, L. N.; West, K. W.; Baldwin, K. W.; Shayegan, M.; Winkler, R.

    2017-01-01

    The concept of a Fermi surface, the constant-energy surface containing all the occupied electron states in momentum, or wave-vector (k ) , space plays a key role in determining electronic properties of conductors. In two-dimensional (2D) carrier systems, the Fermi surface becomes a contour which, in the simplest case, encircles the occupied states. In this case, the area enclosed by the contour, which we refer to as the Fermi sea (FS), is a simple disk. Here we report the observation of an FS with a new topology, namely, an FS in the shape of an annulus. Such an FS is expected in a variety of 2D systems where the energy band dispersion supports a ring of extrema at finite k , but its experimental observation has been elusive. Our study provides (1) theoretical evidence for the presence of an annular FS in 2D hole systems confined to wide GaAs quantum wells and (2) experimental signatures of the onset of its occupation as an abrupt rise in the sample resistance, accompanied by a sudden appearance of Shubnikov-de Haas oscillations at an unexpectedly high frequency whose value does not simply correspond to the (negligible) density of holes contained within the annular FS.

  14. Annular and Total Solar Eclipses of 2010

    Science.gov (United States)

    Espenak, Fred; Anderson, J.

    2008-01-01

    While most NASA eclipse bulletins cover a single eclipse, this publication presents predictions for two solar eclipses during 2010. This has required a different organization of the material into the following sections. Section 1 -- Eclipse Predictions: The section consists of a general discussion about the eclipse path maps, Besselian elements, shadow contacts, eclipse path tables, local circumstances tables, and the lunar limb profile. Section 2 -- Annular Solar Eclipse of 2010 Ja n 15: The section covers predictions and weather prospects for the annular eclipse. Section 3 -- Total Solar Eclipse of 2010 Jul 11: The se ction covers predictions and weather prospects for the total eclipse. Section 4 -- Observing Eclipses: The section provides information on eye safety, solar filters, eclipse photography, and making contact timings from the path limits. Section 5 -- Eclipse Resources: The final section contains a number of resources including information on the IAU Working Group on Eclipses, the Solar Eclipse Mailing List, the NASA eclipse bulletins on the Internet, Web sites for the two 2010 eclipses, and a summary identifying the algorithms, ephemerides, and paramete rs used in the eclipse predictions.

  15. Cavitation Effects in Centrifugal Pumps- A Review

    Directory of Open Access Journals (Sweden)

    Maxime Binama

    2016-05-01

    Full Text Available Cavitation is one of the most challenging fluid flow abnormalities leading to detrimental effects on both the centrifugal pump flow behaviors and physical characteristics. Centrifugal pumps’ most low pressure zones are the first cavitation victims, where cavitation manifests itself in form of pitting on the pump internal solid walls, accompanied by noise and vibration, all leading to the pump hydraulic performance degradation. In the present article, a general description of centrifugal pump performance and related parameters is presented. Based on the literature survey, some light were shed on fundamental cavitation features; where different aspects relating to cavitation in centrifugal pumps were briefly discussed

  16. Centrifugal separators and related devices and methods

    Science.gov (United States)

    Meikrantz, David H.; Law, Jack D.; Garn, Troy G.; Macaluso, Lawrence L.; Todd, Terry A.

    2012-03-06

    Centrifugal separators and related methods and devices are described. More particularly, centrifugal separators comprising a first fluid supply fitting configured to deliver fluid into a longitudinal fluid passage of a rotor shaft and a second fluid supply fitting sized and configured to sealingly couple with the first fluid supply fitting are described. Also, centrifugal separator systems comprising a manifold having a drain fitting and a cleaning fluid supply fitting are described, wherein the manifold is coupled to a movable member of a support assembly. Additionally, methods of cleaning centrifugal separators are described.

  17. Virgin Coconut Oil Production by Centrifugation Method

    OpenAIRE

    2014-01-01

    The virgin coconut oil (VCO) production by centrifugation method was studied. The production of VCO was studied by using various centrifugation speed, temperature and time intervals. The results showed that the yield of VCO was 13.53% at 12000rpm, at 120 minutes. The highest yield of VCO was 13.80% at centrifugation temperature of 40oC. The concentration of lauric acid present in the samples with variables of centrifugation temperatures, speed, and time intervals were 0.4543µg, 6.2367µg, and ...

  18. Virgin Coconut Oil Production by Centrifugation Method

    Directory of Open Access Journals (Sweden)

    Y.C.Wong

    2014-03-01

    Full Text Available The virgin coconut oil (VCO production by centrifugation method was studied. The production of VCO was studied by using various centrifugation speed, temperature and time intervals. The results showed that the yield of VCO was 13.53% at 12000rpm, at 120 minutes. The highest yield of VCO was 13.80% at centrifugation temperature of 40oC. The concentration of lauric acid present in the samples with variables of centrifugation temperatures, speed, and time intervals were 0.4543µg, 6.2367µg, and 6.4894µg respectively.

  19. Vortex beam based more stable annular laser guide star

    Science.gov (United States)

    Luo, Ruiyao; Cui, Wenda; Li, Lei; Sun, Quan; He, Yulong; Wang, Hongyan; Ning, Yu; Xu, Xiaojun

    2016-11-01

    We present an annular laser guide star (LGS) concept for large ground-based telescopes in this paper. The more stable annular LGS is generated by turbulence-resisted vortex beam. In the uplink, a vortex beam tends to wander more slightly than a Gaussian beam does in atmospheric turbulence. This may enable an annular LGS to wander more slightly than a traditional Gaussian beam generated LGS does, which would ease the burden of uplink tip-tilt mirror and benefit a dynamical closed-loop adaptive optics system. We conducted numerical simulation to validate the feasibility of this concept. And we have gotten 31% reduced variance of spot wandering of annular LGS. Besides, we set up a spatial light modulator based laser guide star simulator for beam propagation in turbulent atmosphere to experimentally test the annular LGS concept. Preliminary experimental results are given. To the best of our knowledge, it is the first time this concept is formulated.

  20. Effect of annular secondary conductor in a linear electromagnetic stirrer

    Indian Academy of Sciences (India)

    R Madhavan; V Ramanarayanan

    2008-10-01

    This paper presents the variation of average axial force density in the annular secondary conductor of a linear electromagnetic stirrer. Different geometries of secondaries are considered for numerical and experimental validation namely, 1. hollow annular ring, 2. annular ring with a solid cylinder and 3. solid cylinder. Experimental and numerical simulations are performed for a 2-pole in house built 15 kW linear electromagnetic stirrer (EMS). It is observed for a supply current of 200 A at 30 Hz the force densities in the hollow annular ring is 67% higher than the equivalent solid cylinder. The same values are 33% for annular ring with a solid cylinder. Force density variation with supply frequency and current are also reported. Numerical simulations using finite element model are validated with experimental results.

  1. CARBON DIOXIDE REDUCTION CONTACTORS IN SPACE VEHICLES AND OTHER ENCLOSED STRUCTURES,

    Science.gov (United States)

    CONTROLLED ATMOSPHERES, CARBON DIOXIDE , REMOVAL, LIFE SUPPORT SYSTEMS, SPACE ENVIRONMENTS, CONFINED ENVIRONMENTS, OXYGEN CONSUMPTION, REGENERATION(ENGINEERING), CHEMISORPTION, MASS TRANSFER, FLUID MECHANICS, CENTRIFUGES.

  2. DETERMINATION OF LIQUID FILM THICKNESS FOLLOWING DRAINING OF CONTACTORS, VESSELS, AND PIPES IN THE MCU PROCESS

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, M; Fernando Fondeur, F; Samuel Fink, S

    2006-06-06

    The Department of Energy (DOE) identified the caustic side solvent extraction (CSSX) process as the preferred technology to remove cesium from radioactive waste solutions at the Savannah River Site (SRS). As a result, Washington Savannah River Company (WSRC) began designing and building a Modular CSSX Unit (MCU) in the SRS tank farm to process liquid waste for an interim period until the Salt Waste Processing Facility (SWPF) begins operations. Both the solvent and the strip effluent streams could contain high concentrations of cesium which must be removed from the contactors, process tanks, and piping prior to performing contactor maintenance. When these vessels are drained, thin films or drops will remain on the equipment walls. Following draining, the vessels will be flushed with water and drained to remove the flush water. The draining reduces the cesium concentration in the vessels by reducing the volume of cesium-containing material. The flushing, and subsequent draining, reduces the cesium in the vessels by diluting the cesium that remains in the film or drops on the vessel walls. MCU personnel requested that Savannah River National Laboratory (SRNL) researchers conduct a literature search to identify models to calculate the thickness of the liquid films remaining in the contactors, process tanks, and piping following draining of salt solution, solvent, and strip solution. The conclusions from this work are: (1) The predicted film thickness of the strip effluent is 0.010 mm on vertical walls, 0.57 mm on horizontal walls and 0.081 mm in horizontal pipes. (2) The predicted film thickness of the salt solution is 0.015 mm on vertical walls, 0.74 mm on horizontal walls, and 0.106 mm in horizontal pipes. (3) The predicted film thickness of the solvent is 0.022 mm on vertical walls, 0.91 mm on horizontal walls, and 0.13 mm in horizontal pipes. (4) The calculated film volume following draining is: (a) Salt solution receipt tank--1.6 gallons; (b) Salt solution feed

  3. Centrifuge modelling of offshore monopile foundation

    DEFF Research Database (Denmark)

    Klinkvort, Rasmus Tofte; Hededal, Ole

    2010-01-01

    centrifuge tests on a laterally loaded monopile in dry sand. The prototype dimension of the piles was modelled to a diameter of 1 meter and penetration depth on 6 meter. The test series were designed in order to investigate the scaling laws in the centrifuge both for monotonic and cyclic loading...

  4. Centrifugal innervation of the mammalian olfactory bulb.

    Science.gov (United States)

    Matsutani, Shinji; Yamamoto, Noboru

    2008-12-01

    Although it has been known for decades that the mammalian olfactory bulb receives a substantial number of centrifugal inputs from other regions of the brain, relatively few data have been available on the function of the centrifugal olfactory system. Knowing the role of the centrifugal projection and how it works is of critical importance to fully understanding olfaction. The centrifugal fibers can be classified into two groups, a group that release neuromodulators, such as noradrenaline, serotonin, or acetylcholine, and a group originating in the olfactory cortex. Accumulating evidence suggests that centrifugal neuromodulatory inputs are associated with acquisition of odor memory. Because the distribution of the terminals on these fibers is diffuse and widespread, the neuromodulatory inputs must affect diverse subsets of bulbar neurons at the same time. In contrast, knowledge of the role of centrifugal fibers from the olfactory cortical areas is limited. Judging from recent morphological evidence, these fibers may modify the activity of neurons located in sparse and discrete loci in the olfactory bulb. Given the modular organization of the olfactory bulb, centrifugal fibers from the olfactory cortex may help coordinate the activities of restricted subsets of neurons belonging to distinct functional modules in an odor-specific manner. Because the olfactory cortex receives inputs from limbic and neocortical areas in addition to inputs from the bulb, the centrifugal inputs from the cortex can modulate odor processing in the bulb in response to non-olfactory as well as olfactory cues.

  5. Rotor for a pyrolysis centrifuge reactor

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a rotor for a pyrolysis centrifuge reactor, said rotor comprising a rotor body having a longitudinal centre axis, and at least one pivotally mounted blade being adapted to pivot around a pivot axis under rotation of the rotor body around the longitudinal centre axis....... Moreover, the present invention relates to a pyrolysis centrifuge reactor applying such a rotor....

  6. Regeneration of Alkanolamine Solutions in Membrane Contactor Based on Novel Polynorbornene

    Directory of Open Access Journals (Sweden)

    Shutova A.A.

    2014-11-01

    Full Text Available For the first time, a novel highly permeable glassy polymer, addition poly[bis(trimethylsilyltricyclononene] (PBTMST, was proposed for its use in a gas-liquid membrane contactor for the regeneration of CO2 absorption liquids (desorption of CO2. This membrane material possesses a good chemical stability and high barrier properties for a number of alkanolmines (30 wt% solutions of MEA, DEA, MDEA, AMP, DEAE or AEAE under typical regeneration conditions (T = 100°C. Studies on gas transport properties of PBTMST (100°C and 1-40 bar show that permeability coefficients of oxygen, nitrogen and carbon dioxide initially tend to decrease, and then level off after first 6-8 hours of operation. This behavior can be explained by partial relaxation of the free-volume structure of PBTMST, no chemical degradation of polymer material at high temperature was confirmed by IR analysis. At the same time, this membrane material preserves high gas permeability coefficients which are higher than those of conventional materials used in the membrane contactors. Gas-liquid membrane contactor based on dense PBTMST membrane shows a good, stable performance; particularly, CO2 loading in diethanolamine solution (30 wt% can be reduced for 0.05-0.34 mole/mole by single pass through the membrane desorber at 100°C and elevated pressure. It seems that desorption rate here is mainly controlled by liquid phase because decreasing of membrane thickness by 50% (from 31 to 21 μm leads to improvement of DEA regeneration only by 1.5-8.5%.

  7. Annular nanoantenna on fibre micro-axicon.

    Science.gov (United States)

    Grosjean, T; Fahys, A; Suarez, M; Charraut, D; Salut, R; Courjon, D

    2008-02-01

    In this paper, we propose to extend the concept of loop antenna to the optical domain. The aim is to develop a new generation of optical nanocollectors that are sensitive to specific electric or magnetic vectorial field components. For validating our approach, a preliminary one-micron-diameter gold nanoring is micromachined on the apex of a cone lens obtained from a tapered optical fibre. It is shown that such a nano-object behaves as a nano-antenna able to detect the longitudinal electric field from a Bessel beam in radial polarization and the longitudinal magnetic component from a Bessel beam in azimuthal polarization. In the latter case, the annular nano-antenna exhibits the properties of an optical inductance.

  8. Trauma-related papular granuloma annular.

    Science.gov (United States)

    Hu, Stephanie W; Kaplan, Jennifer; Patel, Rishi R; Kamino, Hideko

    2013-12-16

    Granuloma annulare (GA) is a benign, granulomatous disease with several clinical manifestations, which include localized, generalized, perforating, subcutaneous, patch, papular, and linear forms. We report a case of papular GA of the dorsal aspects of the hands that arose after repeated, direct trauma to the site of subsequent involvement. Although multiple etiologies for GA have been proposed, which include ultraviolet light, arthropod bites, trauma, tuberculin skin tests, viral infections, and PUVA photochemotherapy, the underlying pathogenesis of the disorder remains unclear. However, owing to the key histopathologic findings of focal collagen and elastic fiber degeneration and mucin deosition in GA, it is not surprising that cutaneous trauma may have played a role in connective tissue injury, subsequent degeneration, and the production of a granulomatous response with increased mucin deposition.

  9. Recurrent Annular Peripheral Choroidal Detachment after Trabeculectomy

    Science.gov (United States)

    Liu, Shaohui; Sun, Lisa L.; Kavanaugh, A. Scott; Langford, Marlyn P.; Liang, Chanping

    2013-01-01

    We report a challenging case of recurrent flat anterior chamber without hypotony after trabeculectomy in a 54-year-old Black male with a remote history of steroid-treated polymyositis, cataract surgery, and uncontrolled open angle glaucoma. The patient presented with a flat chamber on postoperative day 11, but had a normal fundus exam and intraocular pressure (IOP). Flat chamber persisted despite treatment with cycloplegics, steroids, and a Healon injection into the anterior chamber. A transverse B-scan of the peripheral fundus revealed a shallow annular peripheral choroidal detachment. The suprachoroidal fluid was drained. The patient presented 3 days later with a recurrent flat chamber and an annular peripheral choroidal effusion. The fluid was removed and reinforcement of the scleral flap was performed with the resolution of the flat anterior chamber. A large corneal epithelial defect developed after the second drainage. The oral prednisone was tapered quickly and the topical steroid was decreased. One week later, his vision decreased to count fingers with severe corneal stromal edema and Descemet's membrane folds that improved to 20/50 within 24 h of resumption of the oral steroid and frequent topical steroid. The patient's visual acuity improved to 20/20 following a slow withdrawal of the oral and topical steroid. Eight months after surgery, the IOP was 15 mm Hg without glaucoma medication. The detection of a shallow anterior choroidal detachment by transverse B-scan is critical to making the correct diagnosis. Severe cornea edema can occur if the steroid is withdrawn too quickly. Thus, steroids should be tapered cautiously in steroid-dependent patients. PMID:24348402

  10. Recurrent Annular Peripheral Choroidal Detachment after Trabeculectomy

    Directory of Open Access Journals (Sweden)

    Shaohui Liu

    2013-10-01

    Full Text Available We report a challenging case of recurrent flat anterior chamber without hypotony after trabeculectomy in a 54-year-old Black male with a remote history of steroid-treated polymyositis, cataract surgery, and uncontrolled open angle glaucoma. The patient presented with a flat chamber on postoperative day 11, but had a normal fundus exam and intraocular pressure (IOP. Flat chamber persisted despite treatment with cycloplegics, steroids, and a Healon injection into the anterior chamber. A transverse B-scan of the peripheral fundus revealed a shallow annular peripheral choroidal detachment. The suprachoroidal fluid was drained. The patient presented 3 days later with a recurrent flat chamber and an annular peripheral choroidal effusion. The fluid was removed and reinforcement of the scleral flap was performed with the resolution of the flat anterior chamber. A large corneal epithelial defect developed after the second drainage. The oral prednisone was tapered quickly and the topical steroid was decreased. One week later, his vision decreased to count fingers with severe corneal stromal edema and Descemet's membrane folds that improved to 20/50 within 24 h of resumption of the oral steroid and frequent topical steroid. The patient's visual acuity improved to 20/20 following a slow withdrawal of the oral and topical steroid. Eight months after surgery, the IOP was 15 mm Hg without glaucoma medication. The detection of a shallow anterior choroidal detachment by transverse B-scan is critical to making the correct diagnosis. Severe cornea edema can occur if the steroid is withdrawn too quickly. Thus, steroids should be tapered cautiously in steroid-dependent patients.

  11. Annular MHD Physics for Turbojet Energy Bypass

    Science.gov (United States)

    Schneider, Steven J.

    2011-01-01

    The use of annular Hall type MHD generator/accelerator ducts for turbojet energy bypass is evaluated assuming weakly ionized flows obtained from pulsed nanosecond discharges. The equations for a 1-D, axisymmetric MHD generator/accelerator are derived and numerically integrated to determine the generator/accelerator performance characteristics. The concept offers a shockless means of interacting with high speed inlet flows and potentially offers variable inlet geometry performance without the complexity of moving parts simply by varying the generator loading parameter. The cycle analysis conducted iteratively with a spike inlet and turbojet flying at M = 7 at 30 km altitude is estimated to have a positive thrust per unit mass flow of 185 N-s/kg. The turbojet allowable combustor temperature is set at an aggressive 2200 deg K. The annular MHD Hall generator/accelerator is L = 3 m in length with a B(sub r) = 5 Tesla magnetic field and a conductivity of sigma = 5 mho/m for the generator and sigma= 1.0 mho/m for the accelerator. The calculated isentropic efficiency for the generator is eta(sub sg) = 84 percent at an enthalpy extraction ratio, eta(sub Ng) = 0.63. The calculated isentropic efficiency for the accelerator is eta(sub sa) = 81 percent at an enthalpy addition ratio, eta(sub Na) = 0.62. An assessment of the ionization fraction necessary to achieve a conductivity of sigma = 1.0 mho/m is n(sub e)/n = 1.90 X 10(exp -6), and for sigma = 5.0 mho/m is n(sub e)/n = 9.52 X 10(exp -6).

  12. Characteristics of Electromagnetic Pulse Coupling into Annular Apertures

    Directory of Open Access Journals (Sweden)

    Yan-Peng Sun

    2013-11-01

    Full Text Available Electromagnetic pulse (EMP coupling into the annular apertures can disturb or damage much electronic equipment. To enhance electronic system’s  capability of anti-electromagnetic interference, the finite difference time domain method (FDTD was employed to study the characteristics of electromagnetic pulse coupling into the cavity enclosures with annular apertures. The coupling characteristics of annular apertures with different shapes (rectangle, square and circle were discussed. It shows that, in the case of the same aperture area, the coupling energy of electromagnetic pulse into the circular annular aperture is smaller than that into the rectangular and the square ones. To the rectangular annular aperture, while the polarization direction of the incident electromagnetic pulse is perpendicular to the long side of the rectangular annular aperture, the coupling energy is larger when the aspect ratio of the rectangular annular aperture is larger. The coupling effect of incident pulse with short pulse width is obviously better than the one with longer pulse width. The resonance phenomenon of the coupled waveform occurs in the cavity.

  13. Centrifugal membrane filtration -- Task 9

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-08-01

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

  14. Radiation and reflection acoustical fields of an annular phased array

    Institute of Scientific and Technical Information of China (English)

    LAI Puxiang; ZHANG Bixing; WANG Chenghao

    2007-01-01

    The characteristics of the radiation and reflection acoustical fields of an annular phased array are investigated. The effects of the element number, element radius, interelement spacing, centre frequency, focus position, and other parameters on the radiation acoustical field of the annular phased array is theoretically studied. In experiment, an annular transducer with 8 equal-area elements is designed and fabricated, and a series of experimental measurements are conducted. The radiation acoustical field and its reflection on a liquid-solid interface are theoretically and experimentally studied. The experimental result is in good agreement with the theoretical one.

  15. Centrifuge workers study. Phase II, completion report

    Energy Technology Data Exchange (ETDEWEB)

    Wooten, H.D.

    1994-09-01

    Phase II of the Centrifuge Workers Study was a follow-up to the Phase I efforts. The Phase I results had indicated a higher risk than expected among centrifuge workers for developing bladder cancer when compared with the risk in the general population for developing this same type of cancer. However, no specific agent could be identified as the causative agent for these bladder cancers. As the Phase II Report states, Phase I had been limited to workers who had the greatest potential for exposure to substances used in the centrifuge process. Phase II was designed to expand the survey to evaluate the health of all employees who had ever worked in Centrifuge Program Departments 1330-1339 but who had not been interviewed in Phase I. Employees in analytical laboratories and maintenance departments who provided support services for the Centrifuge Program were also included in Phase II. In December 1989, the Oak Ridge Associated Universities (ORAU), now known as Oak Ridge Institute for Science and Education (ORISE), was contracted to conduct a follow-up study (Phase II). Phase H of the Centrifuge Workers Study expanded the survey to include all former centrifuge workers who were not included in Phase I. ORISE was chosen because they had performed the Phase I tasks and summarized the corresponding survey data therefrom.

  16. Analysis of ammonia separation from purge gases in microporous hollow fiber membrane contactors.

    Science.gov (United States)

    Karami, M R; Keshavarz, P; Khorram, M; Mehdipour, M

    2013-09-15

    In this study, a mathematical model was developed to analyze the separation of ammonia from the purge gas of ammonia plants using microporous hollow fiber membrane contactors. A numerical procedure was proposed to solve the simultaneous linear and non linear partial differential equations in the liquid, membrane and gas phases for non-wetted or partially wetted conditions. An equation of state was applied in the model instead of Henry's law because of high solubility of ammonia in water. The experimental data of CO₂-water system in the literature was used to validate the model due to the lack of data for ammonia-water system. The model showed that the membrane contactor can separate ammonia very effectively and with recoveries higher than 99%. SEM images demonstrated that ammonia caused some micro-cracks on the surfaces of polypropylene fibers, which could be an indication of partial wetting of membrane in long term applications. However, the model results revealed that the membrane wetting did not have significant effect on the absorption of ammonia because of very high solubility of ammonia in water. It was also found that the effect of gas velocity on the absorption flux was much more than the effect of liquid velocity.

  17. Counteracting ammonia inhibition in anaerobic digestion by removal with a hollow fiber membrane contactor.

    Science.gov (United States)

    Lauterböck, B; Ortner, M; Haider, R; Fuchs, W

    2012-10-01

    The aim of the current study was to investigate the feasibility of membrane contactors for continuous ammonia (NH₃-N) removal in an anaerobic digestion process and to counteract ammonia inhibition. Two laboratory anaerobic digesters were fed slaughterhouse wastes with ammonium (NH₄⁺) concentrations ranging from 6 to 7.4 g/L. One reactor was used as reference reactor without any ammonia removal. In the second reactor, a hollow fiber membrane contactor module was used for continuous ammonia removal. The hollow fiber membranes were directly submerged into the digestate of the anaerobic reactor. Sulfuric acid was circulated in the lumen as an adsorbent solution. Using this set up, the NH₄⁺-N concentration in the membrane reactor was significantly reduced. Moreover the extraction of ammonia lowered the pH by 0.2 units. In combination that led to a lowering of the free NH₃-N concentration by about 70%. Ammonia inhibition in the reference reactor was observed when the concentration exceeded 6 g/L NH₄⁺-N or 1-1.2 g/L NH₃-N. In contrast, in the membrane reactor the volatile fatty acid concentration, an indicator for process stability, was much lower and a higher gas yield and better degradation was observed. The chosen approach offers an appealing technology to remove ammonia directly from media having high concentrations of solids and it can help to improve process efficiency in anaerobic digestion of ammonia rich substrates.

  18. Performance analysis of a liquid desiccant and membrane contactor hybrid air-conditioning system

    Energy Technology Data Exchange (ETDEWEB)

    Bergero, Stefano; Chiari, Anna [DIPARC, Faculty of Architecture, University of Genoa, Stradone S. Agostino 37, 16123 Genova (Italy)

    2010-11-15

    The present study examines the performances of a hybrid air-conditioning system in which a vapour-compression inverse cycle is integrated with an air dehumidification system working with hygroscopic solution and hydrophobic membrane. This model may be a valid alternative to traditional summertime air-conditioning system, in which the air is cooled to below its dew-point temperature and subsequently reheated. The proposed hybrid system involves simultaneously cooling and dehumidifying the air conveyed to the conditioned ambient in an air-solution membrane contactor. An LiCl solution is cooled by means of a vapour-compression inverse cycle using the refrigerant KLEA 407C. The solution is regenerated in another membrane contactor by exploiting the heat rejected by the condenser. A SIMULINK calculation programme was designed in order to simulate the system under examination in steady-state conditions. The performances of the system were analysed on varying a few significant operating parameters, and were compared with those of a traditional direct-expansion air-conditioning plant in typical summertime conditions. The results of the simulations revealed significant energy savings, which, in particular operating conditions, may exceed 50%. (author)

  19. Emergency membrane contactor based absorption system for ammonia leaks in water treatment plants

    Institute of Scientific and Technical Information of China (English)

    SHAO Jiahui; FANG Xuliang; HE Yiliang; JIN Qiang

    2008-01-01

    Because of the suspected health risks of trihalomethanes (THMs), more and more water treatment plants have replaced traditionalchlorine disinfection process with chloramines but often without the proper absorption system installed in the case of ammonia leaksin the storage room. A pilot plant membrane absorption system was developed and installed in a water treatment plant for this purpose.Experimentally determined contact angle, surface tension, and corrosion tests indicated that the sulfuric acid was the proper choice as the absorbent for leaking ammonia using polypropylene hollow fiber membrane contactor. Effects of several operating conditionson the mass transfer coefficient, ammonia absorption, and removal efficiency were examined, including the liquid concentration,liquid velocity, and feed gas concentration. Under the operation conditions investigated, the gas absorption efficiency over 99.9%was achieved. This indicated that the designed pilot plant membrane absorption system was effective to absorb the leaking ammonia in the model storage room. The removal rate of the ammonia in the model storage room was also experimentally and theoretically foundto be primarily determined by the ammonia suction flow rate from the ammonia storage room to the membrane contactor. The ammoniaremoval rate of 99.9% was expected to be achieved within 1.3 h at the ammonia gas flow rate of 500 m3/h. The success of the pilot plantmembrane absorption system developed in this study illustrated the potential of this technology for ammonia leaks in water treatmentplant, also paved the way towards a larger scale application.

  20. Determination of economically justified parameters of synchronous disconnection at low-voltage circuit switching via a synchronous vacuum contactor

    Directory of Open Access Journals (Sweden)

    A.V. Verkhola

    2014-04-01

    Full Text Available Dependence of a single switching procedure cost upon the contact opening delay time and delay-time spread is derived for a low-voltage synchronous vacuum contactor. For different cost levels, boundaries of permissible values of delay-time and delay-time spread are specified.

  1. Talking about the Maintenance of AC Contactor%浅谈交流接触器的维修

    Institute of Scientific and Technical Information of China (English)

    王如军

    2011-01-01

    AC eleOromagnetic contactor as an automatic switch in the control of electrical equipment companies have been widely used. But for various reasons often lead to the emergence of various AC contactor failure or damage. Therefore, there must be targeted to take various measures to do a goodjob AC contactor failure prevention, maintenance and processing, to protect AC contactor to work.%交流接触器作为一种电磁式自动开关在企业电气设备的控制中得到了广泛的应用。但由于各种原因经常导致交流接触器出现各种故障甚至损坏。因此,必须有针对性地采取各种措施,认真做好交流接触器故障的预防、维护和处理工作,保障交流接触器正常工作。

  2. INACTIVATION OF CRYPTOSPORIDIUM OOCYSTS IN A PILOT-SCALE OZONE BUBBLE-DIFFUSER CONTACTOR - II: MODEL VALIDATION AND APPLICATION

    Science.gov (United States)

    The ADR model developed in Part I of this study was successfully validated with experimenta data obtained for the inactivation of C. parvum and C. muris oocysts with a pilot-scale ozone-bubble diffuser contactor operated with treated Ohio River water. Kinetic parameters, required...

  3. FLOW REGIMES, GAS HOLD-UP AND AXIAL GAS MIXING IN THE GAS-LIQUID MULTISTAGE AGITATED CONTACTOR

    NARCIS (Netherlands)

    BREMAN, BB; BEENACKERS, AACM; BOUMA, MJ

    1995-01-01

    Experimental data are reported on Row regimes, gas hold-up and axial gas mixing of a gas-liquid Multi-stage Agitated Contactor (MAC), consisting of nine compartments [height, H, over diameter, D = 1; D = 0.09 m) separated by horizontal baffles with an opening of 0.04 m and with one centrally positio

  4. Microporous hollow fibre membrane modules as gas-liquid contactors. Part 1. Physical mass transfer processes : A specific application

    NARCIS (Netherlands)

    Kreulen, H.; Versteeg, G.F.; Swaaij, W.P.M. van

    1993-01-01

    Gas-liquid mass transfer has been studied in a membrane module with non-wetted microporous fibres in the laminar flow regime. This new type of gas/liquid contactor can be operated stabily over a large range of gas and liquid flows because gas and liquid phase do not influence each other directly. Th

  5. Membrane contactor/separator for an advanced ozone membrane reactor for treatment of recalcitrant organic pollutants in water

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Wai Kit, E-mail: kekyeung@ust.hk [Department of Chemical and Biomolecular Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong); Joueet, Justine; Heng, Samuel; Yeung, King Lun [Department of Chemical and Biomolecular Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong); Schrotter, Jean-Christophe [Water Research Center of Veolia, Anjou Recherche, Chemin de la Digue, BP 76. 78603, Maisons Laffitte, Cedex (France)

    2012-05-15

    An advanced ozone membrane reactor that synergistically combines membrane distributor for ozone gas, membrane contactor for pollutant adsorption and reaction, and membrane separator for clean water production is described. The membrane reactor represents an order of magnitude improvement over traditional semibatch reactor design and is capable of complete conversion of recalcitrant endocrine disrupting compounds (EDCs) in water at less than three minutes residence time. Coating the membrane contactor with alumina and hydrotalcite (Mg/Al=3) adsorbs and traps the organics in the reaction zone resulting in 30% increase of total organic carbon (TOC) removal. Large surface area coating that diffuses surface charges from adsorbed polar organic molecules is preferred as it reduces membrane polarization that is detrimental to separation. - Graphical abstract: Advanced ozone membrane reactor synergistically combines membrane distributor for ozone, membrane contactor for sorption and reaction and membrane separator for clean water production to achieve an order of magnitude enhancement in treatment performance compared to traditional ozone reactor. Highlights: Black-Right-Pointing-Pointer Novel reactor using membranes for ozone distributor, reaction contactor and water separator. Black-Right-Pointing-Pointer Designed to achieve an order of magnitude enhancement over traditional reactor. Black-Right-Pointing-Pointer Al{sub 2}O{sub 3} and hydrotalcite coatings capture and trap pollutants giving additional 30% TOC removal. Black-Right-Pointing-Pointer High surface area coating prevents polarization and improves membrane separation and life.

  6. Virtual cathode microwave generator having annular anode slit

    Science.gov (United States)

    Kwan, Thomas J. T.; Snell, Charles M.

    1988-01-01

    A microwave generator is provided for generating microwaves substantially from virtual cathode oscillation. Electrons are emitted from a cathode and accelerated to an anode which is spaced apart from the cathode. The anode has an annular slit therethrough effective to form the virtual cathode. The anode is at least one range thickness relative to electrons reflecting from the virtual cathode. A magnet is provided to produce an optimum magnetic field having the field strength effective to form an annular beam from the emitted electrons in substantial alignment with the annular anode slit. The magnetic field, however, does permit the reflected electrons to axially diverge from the annular beam. The reflected electrons are absorbed by the anode in returning to the real cathode, such that substantially no reflexing electrons occur. The resulting microwaves are produced with a single dominant mode and are substantially monochromatic relative to conventional virtual cathode microwave generators.

  7. Phased annular array transducers for ultrasonic guided wave applications

    Science.gov (United States)

    Yan, Fei; Borigo, Cody; Liang, Yue; Koduru, Jaya P.; Rose, Joseph L.

    2011-04-01

    Mode and frequency control always plays an important role in ultrasonic guided wave applications. In this paper, theoretical understanding of guided wave excitations of axisymmetric sources on plate structures is established. It is shown that a wave number spectrum can be used to investigate the guided wave excitations of an axisymmetric source. The wave number spectrum is calculated from a Hankel transform of the axial source loading profile. On the basis of the theoretical understanding, phased annular array transducers are developed as a powerful tool for guided wave mode and frequency control. By applying appropriate time delays to phase the multiple elements of an annular array transducer, guided wave mode and frequency tuning can be achieved fully electronically. The phased annular array transducers have been successfully used for various applications. Example applications presented in this paper include phased annular arrays for guided wave beamforming and a novel ultrasonic vibration modal analysis technique for damage detection.

  8. Gas dynamics in strong centrifugal fields

    Energy Technology Data Exchange (ETDEWEB)

    Bogovalov, S.V.; Kislov, V.A.; Tronin, I.V. [National research nuclear university “MEPhI”, Kashirskoje shosse, 31,115409, Moscow (Russian Federation)

    2015-03-10

    Dynamics of waves generated by scopes in gas centrifuges (GC) for isotope separation is considered. The centrifugal acceleration in the GC reaches values of the order of 106g. The centrifugal and Coriolis forces modify essentially the conventional sound waves. Three families of the waves with different polarisation and dispersion exist in these conditions. Dynamics of the flow in the model GC Iguasu is investigated numerically. Comparison of the results of the numerical modelling of the wave dynamics with the analytical predictions is performed. New phenomena of the resonances in the GC is found. The resonances occur for the waves polarized along the rotational axis having the smallest dumping due to the viscosity.

  9. Dewatering of fine coal using hyperbaric centrifugation

    Energy Technology Data Exchange (ETDEWEB)

    Ramazan Asmatulu; Gerald H. Luttrell; Roe-Hoan Yoon [Virginia Polytechnic Institute and State University, Blacksburg, VA (US). Center for Advanced Separation Technologies

    2005-09-01

    Many coal preparation plants are forced to discard their fine coal because of the inability of existing technologies to reduce the moisture content of this product to an acceptable level. In an effort to overcome this problem, a new mechanical dewatering method has been developed that combines centrifugation with pressure filtration. The process, which may be referred to as hyperbaric centrifugation, is capable of producing a drier product than can be achieved using either filtration or centrifugation alone. The test data obtained from batch experiments show that the new method can reduce cake moisture to 10% or below for many fine coal product streams.

  10. Polyharmonic functions of infinite order on annular regions

    OpenAIRE

    Kounchev, Ognyan; Render, Hermann

    2013-01-01

    Polyharmonic functions $f$ of infinite order and type $\\tau$ on annular regions are systematically studied. The first main result states that the Fourier-Laplace coefficients $f_{k,l}(r)$ of a polyharmonic function $f$ of infinite order and type $0$ can be extended to analytic functions on the complex plane cut along the negative semiaxis. The second main result gives a constructive procedure via Fourier-Laplace series for the analytic extension of a polyharmonic function on annular ...

  11. Experiments on soliton motion in annular Josephson junctions

    DEFF Research Database (Denmark)

    Davidson, A.; Dueholm, B.; Pedersen, Niels Falsig

    1986-01-01

    We report here the results of an extensive experimental investigation of soliton dynamics in Josephson junctions of different annular geometries. The annular geometry is unique in that it allows for the study of undisturbed soliton motion as well as soliton–antisoliton collisons, since there are ...... for a single trapped soliton, and evidence linking the stability of the soliton to surface damping. Journal of Applied Physics is copyrighted by The American Institute of Physics....

  12. Modeling of Centrifugal Force Field and the Effect on Filling and Solidification in Centrifugal Casting

    Science.gov (United States)

    Sheng, Wenbin; Ma, Chunxue; Gu, Wanli

    2011-06-01

    Based on the steady flow in a tube, a mathematical model has been established for the consideration of centrifuging force field by combining the equations of continuity, conservation of momentum and general energy. Effects of centrifugal field on the filling and solidification are modeled by two accessional terms: centrifugal force and Chorios force. In addition, the transfer of heat by convection is considered to achieve a coupling calculation of velocity field and temperature field. The solution of pressure item is avoided by introducing the stream function ψ(x,y) and the eddy function ξ(x,y). Corresponding difference formats for the simultaneous equations of centrifugal filling, the accessional terms and the solidifying latent heat have been established by the finite difference technique. Furthermore, the centrifugal filling and solidification processes in a horizontal tube are summarized to interpret the mechanism by which internal defects are formed in centrifugal castings.

  13. New mitral annular force transducer optimized to distinguish annular segments and multi-plane forces.

    Science.gov (United States)

    Skov, Søren Nielsen; Røpcke, Diana Mathilde; Ilkjær, Christine; Rasmussen, Jonas; Tjørnild, Marcell Juan; Jimenez, Jorge H; Yoganathan, Ajit P; Nygaard, Hans; Nielsen, Sten Lyager; Jensen, Morten Olgaard

    2016-03-21

    Limited knowledge exists about the forces acting on mitral valve annuloplasty repair devices. The aim of this study was to develop a new mitral annular force transducer to measure the forces acting on clinically used mitral valve annuloplasty devices. The design of an X-shaped transducer in the present study was optimized for simultaneous in- and out-of-plane force measurements. Each arm was mounted with strain gauges on four circumferential elements to measure out-of-plane forces, and the central parts of the X-arms were mounted with two strain gauges to measure in-plane forces. A dedicated calibration setup was developed to calibrate isolated forces with tension and compression for in- and out-of-plane measurements. With this setup, it was possible with linear equations to isolate and distinguish measured forces between the two planes and minimize transducer arm crosstalk. An in-vitro test was performed to verify the crosstalk elimination method and the assumptions behind it. The force transducer was implanted and evaluated in an 80kg porcine in-vivo model. Following crosstalk elimination, in-plane systolic force accumulation was found to be in average 4.0±0.1N and the out-of-plane annular segments experienced an average force of 1.4±0.4N. Directions of the systolic out-of-plane forces indicated movements towards a saddle shaped annulus, and the transducer was able to measure independent directional forces in individual annular segments. Further measurements with the new transducer coupled with clinical annuloplasty rings will provide a detailed insight into the biomechanical dynamics of these devices.

  14. Design and evaluation of hydraulic baffled-channel PAC contactor for taste and odor removal from drinking water supplies.

    Science.gov (United States)

    Kim, Young-Il; Bae, Byung-Uk

    2007-05-01

    Based on the concept of hydraulic flocculator, a baffled-channel powdered activated carbon (PAC) contactor, placed before the rapid-mixing basin, was designed and evaluated for removal of taste and odor (T&O) in drinking water. PAC adsorption kinetic tests for raw water samples were conducted for selection of design parameters related to contact time and degree of mixing. Within the tested range of velocity gradient (G) from 18 to 83s(-1), mixing had a relatively minor effect on the adsorption kinetics of the PAC. The hydrodynamic characteristics of the pilot-scale horizontally and vertically baffled-channel PAC contactor were investigated by tracer tests. It was found that the plug flow fractions of vertically baffled-channel PAC contactor (vBPC) were higher than those of the horizontally baffled-channel PAC contactor (hBPC) for the same bend width or bend height. However, the hBPC seems to be more appropriate than the vBPC in terms of construction and maintenance. The geosmin and MIB removal rate increased with the number of baffles, PAC dose and contact time increased regardless of bend width in the pilot-scale hBPC. The pair of full-scale hBPCs at Pohang water treatment plant, having a design capacity of 6.5x10(4)m(3)/d with 20min of hydraulic retention time with a safety factor of 2, was designed based on lab- and pilot-scale experimental results. Under a velocity gradient of 20s(-1), the number of baffles to be installed was calculated to be 20 with a space of about 2m between each baffle, resulting in a hydraulic head loss through the contactor of about 0.056m. The successful application of hBPC for T&O removal from drinking water supplies should provide momentum for developing more effective treatment methods.

  15. Deburring by centrifugal barrel tumbling

    Energy Technology Data Exchange (ETDEWEB)

    Gillespie, L.K.

    1976-08-01

    The reliability of small precision mechanisms greatly depends upon the production of burr-free, sharp-edged parts. Centrifugal barrel finishing (Harperizing) is one of the few processes capable of producing these conditions. Burrs less than 0.001-in. thick by 0.001-in. high (25.4 x 25.4 ..mu..m) can be removed from 303 Se stainless steel, 1018 steel, and 6061-T6 aluminum with dimensional changes in the order of 0.0001-in. (2.54 ..mu..m) and final edge radii of 0.003 in. (76.2 ..mu..m). These conditions can be produced in batch lots in 20 minutes or less. Surface finishes can be reduced from 45 to 25 or 35 microinches (1.15 to 0.68 or 0.89 ..mu..m), with 60-minute cycle times. Stock losses appear to be repeatable within +-0.00006 in. (1.524 ..mu..m). Very small parts receive less action than parts 0.5 in. (12.7 mm) in dia.

  16. Sonographic evaluation of digital annular pulley tears

    Energy Technology Data Exchange (ETDEWEB)

    Martinoli, C.; Derchi, L.E. [Istituto di Radiologia, Universita di Genova, Genoa (Italy); Bianchi, S.; Garcia, J.F. [Dept. de Radiologie, Hopital Cantonal Universitaire de Geneve (Switzerland); Nebiolo, M. [Reparto Pronto Soccorso Medico, Pietra Ligure (Italy)

    2000-07-01

    Objective. To evaluate the sonographic (US) appearance of digital annular pulley (DAP) tears in high-level rock climbers. Design and patients. We performed a retrospective analysis of the US examinations of 16 high-level rock climbers with clinical signs of DAP lesions. MRI and surgical evaluation were performed in five and three patients respectively. The normal US and MRI appearances of DAP were evaluated in 40 and three normal fingers respectively. Results. Nine of 16 patients presented a DAP tear. In eight subjects (seven with complete tears involving the fourth finger and one the fifth finger), US diagnosis was based on the indirect sign of volar bowstringing of the flexor tendons. Injured pulleys were not appreciated by US. Tears concerned the A2 and A3 in six patients and the A3 and A4 in two patients. A2 pulley thickening and hypoechogenicity compatible with a partial tear was demonstrated in one patient. MRI and surgical data correlated well with the US findings. Four patients had tenosynovitis of the flexor tendons but no evidence of pulley disruption. US examinations of three patients were normal. In the healthy subjects US demonstrated DAP in 16 of 40 digits. Conclusion. US can diagnose DAP tears and correlates with the MRI and surgical data. Because of its low cost and non-invasiveness we suggest US as the first imaging modality in the evaluation of injuries of the digital pulley. (orig.)

  17. Impulsively started, steady and pulsated annular inflows

    Science.gov (United States)

    Abdel-Raouf, Emad; Sharif, Muhammad A. R.; Baker, John

    2017-04-01

    A computational investigation was carried out on low Reynolds number laminar inflow starting annular jets using multiple blocking ratios and atmospheric ambient conditions. The jet exit velocity conditions are imposed as steady, unit pulsed, and sinusoidal pulsed while the jet surroundings and the far-field jet inlet upstream conditions are left atmospheric. The reason is to examine the flow behavior in and around the jet inlet under these conditions. The pulsation mode behavior is analyzed based on the resultant of the momentum and pressure forces at the entry of the annulus, the circulation and vortex formation, and the propulsion efficiency of the inflow jets. The results show that under certain conditions, the net force of inflow jets (sinusoidal pulsed jets in particular) could point opposite to the flow direction due to the adverse pressure drops in the flow. The propulsion efficiency is also found to increase with pulsation frequency and the sinusoidal pulsed inflow jets are more efficient than the unit pulsed inflow jets. In addition, steady inflow jets did not trigger the formation of vortices, while unit and sinusoidal pulsed inflow jets triggered the formation of vortices under a certain range of frequencies.

  18. Solar cycle modulation of Southern Annular Mode

    Science.gov (United States)

    Kuroda, Yuhji

    2016-04-01

    Climate is known to be affected by various factors, including oceanic changes and volcanic eruptions. 11-year solar cycle change is one of such important factors. Observational analysis shows that the winter-mean North Atlantic Oscillation (NAO) and late-winter/spring Southern Annular Mode (SAM) show structural modulation associated with 11-year solar cycle. In fact, these signals tend to extend from surface to upper stratosphere and persistent longer period only in the High Solar (HS) years. In the present study, we used 35-year record of ERA-Interim reanalysis data and performed wave-energy and momentum analysis on the solar-cycle modulation of the SAM to examine key factors to create such solar-SAM relationship. It is found that enhanced wave-mean flow interaction tends to take place in the middle stratosphere in association with enhanced energy input from diabatic heating on September only in HS years. The result suggests atmospheric and solar conditions on September are keys to create solar-SAM relationship.

  19. Vibration of an eccentrically clamped annular plate

    Science.gov (United States)

    Tseng, J.-G.; Wickert, J. A.

    1994-04-01

    Small amplitude vibration of an eccentric annular plate, which is free along its outer edge and clamped along the interior, is investigated through experimental and analytical methods. A disk with this geometry, or a stacked array in which the clamping and symmetry axes of each disk are nominally coincident, is common in data storage and brake systems applications. In the present case, the geometric imperfections on the boundary can have important implications for the disk's dynamic response. Changes that occur in the natural frequency spectrum, the mode shapes, and the free response under eccentric mounting are studied through laboratory measurements and an approximate discrete model of the plate. The natural frequencies and modes are found through global discretization of the Kamke quotient for a classical thin plate. For the axisymmetric geometry, the natural frequencies of the sine and cosine vibration modes for a specified number of nodal diameters are repeated. With increasing eccentricity, on the other hand, each pair of repeated frequencies splits at a rate that depends on the number of nodal diameters. Over a range of clamping and eccentricity ratios, the model's predictions are compared to the measured results.

  20. Molecular structure and centrifugal distortion in methylthioethyne

    NARCIS (Netherlands)

    Engelsen, D. den

    1969-01-01

    The investigation of the microwave spectra of five isotopic species of methylthioethyne, HCCSCH3 enabled a fairly reliable calculation to be made of bond lengths and angles. The centrifugal distortion parameters are related to molecular vibrations.

  1. Geotechnical Centrifuge Studies of Unsaturated Transport

    Science.gov (United States)

    Smith, R. W.; Mattson, E. D.; Palmer, C. D.

    2007-12-01

    Improved understanding of contaminant migration in heterogeneous, variably saturated porous media is required to better define the long-term stewardship requirements for U.S. Department of Energy (DOE) lands and to assist in the design of effective vadose-zone barriers to contaminant migrations. A geotechnical centrifuge provides an experimental approach to explore vadose zone transport over a wide range of relevant conditions in time frames not possible for conventional bench-top experiments. Our research to date resulted in the design, construction, and testing of in-flight experimental apparatus allowing the replication of traditional bench top unsaturated transport experiments using the 2-meter radius geotechnical centrifuge capabilities at the Idaho National Laboratory. Additionally we conducted a series of unsaturated 1-dimenstional column experiments using conservative tracers to evaluate the effects of increased centrifugal acceleration on derived transport properties and assessing the scaling relationships for these properties. Our experimental results indicated that breakthrough times for a conservative tracer decreased significantly and systematically as a function of increased centrifugal acceleration. Differences between these experimental results and estimates based on predictive scaling rules are due to slight moisture content differences between experiments at different centrifugal accelerations. In contrast, dispersion coefficients varied systemically with centrifugal acceleration in accordance with predictive scaling rules. The results we obtained in this study indicate that the centrifuge technique is a viable experimental method for the study of subsurface processes where gravitational acceleration is important. The geotechnical centrifuge allows experiments to be completed more quickly than tests conducted at 1-gravity and can be used to experimentally address important scaling issues, and permits experiments under a range of conditions that

  2. Combination Of Investment And Centrifugal Casting

    Science.gov (United States)

    Creeger, Gordon A.

    1994-01-01

    Modifications, including incorporation of centrifugal casting, made in investment-casting process reducing scrap rate. Used to make first- and second-stage high-pressure-fuel-turbopump nozzles, containing vanes with thin trailing edges and other thin sections. Investment mold spun for short time while being filled, and stopped before solidification occurs. Centrifugal force drives molten metal into thin trailing edges, ensuring they are filled. With improved filling, preheat and pour temperatures reduced and solidification hastened so less hot tearing.

  3. Clinical experience with the Sarns centrifugal pump.

    Science.gov (United States)

    Curtis, J J; Walls, J T; Demmy, T L; Boley, T M; Schmaltz, R A; Goss, C F; Wagner-Mann, C C

    1993-07-01

    Since October 1986, we have had experience with 96 Sarns centrifugal pumps in 72 patients (pts). Heparinless left atrial to femoral artery or aorta bypass was used in 14 pts undergoing surgery on the thoracic aorta with 13 survivors (93%). No paraplegia or device-related complications were observed. In 57 patients, the Sarns centrifugal pump was used as a univentricular (27 pts) or biventricular (30 pts) cardiac assist device for postcardiotomy cardiogenic shock. In these patients, cardiac assist duration ranged from 2 to 434 h with a hospital survival rate of 29% in those requiring left ventricular assist and 13% in those requiring biventricular assist. Although complications were ubiquitous in this mortally ill patient population, in 5,235 pump-hours, no pump thrombosis was observed. Hospital survivors followed for 4 months to 6 years have enjoyed an improved functional class. We conclude that the Sarns centrifugal pump is an effective cardiac assist device when used to salvage patients otherwise unweanable from cardiopulmonary bypass. Partial left ventricular bypass using a centrifugal pump has become our procedure of choice for unloading the left ventricle and for maintenance of distal aortic perfusion pressure when performing surgery on the thoracic aorta. This clinical experience with the Sarns centrifugal pump appears to be similar to that reported with other centrifugal assist devices.

  4. Multi-point optimization of recirculation flow type casing treatment in centrifugal compressors

    Science.gov (United States)

    Tun, Min Thaw; Sakaguchi, Daisaku

    2016-06-01

    High-pressure ratio and wide operating range are highly required for a turbocharger in diesel engines. A recirculation flow type casing treatment is effective for flow range enhancement of centrifugal compressors. Two ring grooves on a suction pipe and a shroud casing wall are connected by means of an annular passage and stable recirculation flow is formed at small flow rates from the downstream groove toward the upstream groove through the annular bypass. The shape of baseline recirculation flow type casing is modified and optimized by using a multi-point optimization code with a metamodel assisted evolutionary algorithm embedding a commercial CFD code CFX from ANSYS. The numerical optimization results give the optimized design of casing with improving adiabatic efficiency in wide operating flow rate range. Sensitivity analysis of design parameters as a function of efficiency has been performed. It is found that the optimized casing design provides optimized recirculation flow rate, in which an increment of entropy rise is minimized at grooves and passages of the rotating impeller.

  5. X-ray diffraction from bone employing annular and semi-annular beams.

    Science.gov (United States)

    Dicken, A J; Evans, J P O; Rogers, K D; Stone, N; Greenwood, C; Godber, S X; Prokopiou, D; Clement, J G; Lyburn, I D; Martin, R M; Zioupos, P

    2015-08-07

    There is a compelling need for accurate, low cost diagnostics to identify osteo-tissues that are associated with a high risk of fracture within an individual. To satisfy this requirement the quantification of bone characteristics such as 'bone quality' need to exceed that provided currently by densitometry. Bone mineral chemistry and microstructure can be determined from coherent x-ray scatter signatures of bone specimens. Therefore, if these signatures can be measured, in vivo, to an appropriate accuracy it should be possible by extending terms within a fracture risk model to improve fracture risk prediction.In this preliminary study we present an examination of a new x-ray diffraction technique that employs hollow annular and semi-annular beams to measure aspects of 'bone quality'. We present diffractograms obtained with our approach from ex vivo bone specimens at Mo Kα and W Kα energies. Primary data is parameterized to provide estimates of bone characteristics and to indicate the precision with which these can be determined.

  6. Planar Pressure Field Determination in the Initial Merging Zone of an Annular Swirling Jet Based on Stereo-PIV Measurements.

    Science.gov (United States)

    Vanierschot, Maarten; Van den Bulck, Eric

    2008-11-28

    In this paper the static pressure field of an annular swirling jet is measured indirectly using stereo-PIV measurements. The pressure field is obtained from numerically solving the Poisson equation, taken into account the axisymmetry of the flow. At the boundaries no assumptions are made and the exact boundary conditions are applied. Since all source terms can be measured using stereo-PIV and the boundary conditions are exact, no assumptions other than axisymmetry had to be made in the calculation of the pressure field. The advantage of this method of indirect pressure measurement is its high spatial resolution compared to the traditional pitot probes. Moreover this method is non-intrusive while the insertion of a pitot tube disturbs the flow. It is shown that the annular swirling flow can be divided into three regimes: a low, an intermediate and a high swirling regime. The pressure field of the low swirling regime is the superposition of the pressure field of the non-swirling jet and a swirl induced pressure field due to the centrifugal forces of the rotating jet. As the swirl increases, the swirl induced pressure field becomes dominant and for the intermediate and high swirling regimes, the simple radial equilibrium equation holds.

  7. Numerical Simulation and Analysis of CO2 Removal in a Polypropylene Hollow Fiber Membrane Contactor

    Directory of Open Access Journals (Sweden)

    Zhien Zhang

    2014-01-01

    Full Text Available This present study shows a comprehensive 2D numerical model for removal of CO2 in a polypropylene (PP hollow fiber membrane contactor (HFMC using the computational fluid dynamics (CFD method. Monoethanolamine (MEA solution was used as the liquid absorbent in a nonwetting mode. The simulation results represented that higher liquid velocity and concentration and lower gas velocity and concentration led to higher percent of CO2 removal. The most proper parameters for CO2 removal were less than 1 mol m−3 gas concentration and 0.2 m s−1 gas flow rate, and for MEA the values were above 8 mol m−3 concentration and approximately 1 m s−1 liquid velocity. Furthermore, the model was validated with the experiment results. Therefore, the modeling results provided references to the selection of absorbents and operation parameters in the experimental study and pilot-scale applications.

  8. Bioaugmentation for treating transient 4-fluorocinnamic acid shock loads in a rotating biological contactor.

    Science.gov (United States)

    Amorim, Catarina L; Duque, Anouk F; Afonso, Carlos M M; Castro, Paula M L

    2013-09-01

    A rotating biological contactor (RBC) was used to treat shock loadings of 4-fluorocinnamic acid (4-FCA). Intermittent 4-FCA shocks of 35 mg L(-1) were applied (ca. 3 months) with only limited mineralization occurring and accumulation of 4-fluorobenzoate (4-FBA) as an intermediate. After bioaugmentation with a degrading bacterium the RBC was able to deal with 4-FCA intermittent loading of 80 mg L(-1) however, a gradual decline in RBC performance occurred, leading to 4-FBA accumulation. The degrading strain was recovered from the biofilm during 2 months but intermittent feeding may have led to diminishing strain numbers. Distinct bacterial communities in the 1st and the 5th and 10th stages of the RBC were revealed by denaturating gradient gel electrophoresis. Several isolates retrieved from the RBC transformed 4-FCA into 4-FBA but only two strains mineralized the compound. Bioaugmentation allowed removal of the fluorinated compound however intermittent feeding may have compromised the bioreactor efficiency.

  9. Recovery of volatile fatty acids via membrane contactor using flat membranes: experimental and theoretical analysis.

    Science.gov (United States)

    Tugtas, Adile Evren

    2014-07-01

    Volatile fatty acid (VFA) separation from synthetic VFA solutions and leachate was investigated via the use of a membrane contactor. NaOH was used as a stripping solution to provide constant concentration gradient of VFAs in both sides of a membrane. Mass flux (12.23 g/m(2)h) and selectivity (1.599) observed for acetic acid were significantly higher than those reported in the literature and were observed at feed pH of 3.0, flow rate of 31.5 ± 0.9 mL/min, and stripping solution concentration of 1.0 N. This study revealed that the flow rate, stripping solution strength, and feed pH affect the mass transfer of VFAs through the PTFE membrane. Acetic and propionic acid separation performances observed in the present study provided a cost effective and environmental alternative due to elimination of the use of extractants.

  10. The use of the fungus Dichomitus squalens for degradation in rotating biological contactor conditions.

    Science.gov (United States)

    Novotný, Ceněk; Trošt, Nina; Šlušla, Martin; Svobodová, Kateřina; Mikesková, Hana; Válková, Hana; Malachová, Kateřina; Pavko, Aleksander

    2012-06-01

    Biodegradation potential of Dichomitus squalens in biofilm cultures and rotating biological contactor (RBC) was investigated. The fungus formed thick biofilms on inert and lignocellulosic supports and exhibited stable activities of laccase and manganese peroxidase to reach 40-62 and 25-32% decolorization of anthraquinone Remazol Brilliant Blue R and heterocyclic phthalocyanine dyes, respectively. The decolorization ceased when glucose concentration dropped to 1 mmol l(-1). In RBC reactor, respective decolorizations of Remazol Brilliant Blue R and heterocyclic Methylene Blue and Azure B dyes (50 mg l(-1)) attained 99%, 93%, and 59% within 7, 40 and 200 h. The fungus exhibited tolerance to coliform and non-coliform bacteria on rich organic media, the inhibition occurred only on media containing tryptone and NaCl. The degradation efficiency in RBC reactor, capability to decolorize a wide range of dye structures and tolerance to bacterial stress make D. squalens an organism applicable to remediation of textile wastewaters.

  11. Open absorption system for cooling and air conditioning using membrane contactors. 2006 annual report

    Energy Technology Data Exchange (ETDEWEB)

    Conde-Petit, M. [M. Conde Engineering, Zuerich (Switzerland); Weber, R. [Materials Science and Technology (EMPA), Abteilung Bautechnologien, Duebendorf (Switzerland)

    2006-11-15

    This illustrated annual report for 2006 for the Swiss Federal Office of Energy (SFOE) reports on work being done on the development of an open absorption system for cooling and air-conditioning. The report reviews the construction of a first prototype and the manufacture of its components. The conceptual design of this new type of air handling unit (AHU), operating with a liquid desiccant, is discussed. The AHU is to be autonomous and the system will not require additional mechanical refrigeration. It is to be thermally driven at temperatures below 80 {sup o}C. Waste heat sources, solar collectors, district heating plants and co-generation systems are targeted as providers of thermal energy at this temperature level. Work carried out is reported on, including that on two-stream membrane contactors.

  12. Bacterial Cellulose Production by Gluconacetobacter sp. RKY5 in a Rotary Biofilm Contactor

    Science.gov (United States)

    Kim, Yong-Jun; Kim, Jin-Nam; Wee, Young-Jung; Park, Don-Hee; Ryu, Hwa-Won

    A rotary biofilm contactor (RBC) inoculated with Gluconacetobacter sp. RKY5 was used as a bioreactor for improved bacterial cellulose production. The optimal number of disk for bacterial cellulose production was found to be eight, at which bacterial cellulose and cell concentrations were 5.52 and 4.98 g/L. When the aeration rate was maintained at 1.25 vvm, bacterial cellulose and cell concentrations were maximized (5.67 and 5.25 g/L, respectively). The optimal rotation speed of impeller in RBC was 15 rpm. When the culture pH in RBC was not controlled during fermentation, the maximal amount of bacterial cellulose (5.53 g/L) and cells (4.91 g/L) was obtained. Under the optimized culture conditions, bacterial cellulose and cell concentrations in RBC reached to 6.17 and 5.58 g/L, respectively.

  13. Stability study and lyophilization of vitamin E-loaded nanocapsules prepared by membrane contactor.

    Science.gov (United States)

    Khayata, N; Abdelwahed, W; Chehna, M F; Charcosset, C; Fessi, H

    2012-12-15

    In this research, we studied the accelerated stability of vitamin E-loaded nanocapsules (NCs) prepared by the nanoprecipitation method. Vitamin E-loaded NCs were optimized firstly at the laboratory scale and then scaled up using the membrane contactor technique. The optimum conditions of the membrane contactor preparation (pilot scale) produced vitamin E-loaded NCs with an average size of 253 nm, polydispersity index 0.19 and a zeta potential -16 mV. The average size, polydispersity index and zeta potential values were 185 nm, 0.12 and -15 mV, respectively for the NCs prepared at laboratory scale. No significant changes were noticed in these values after 3 and 6 months of storage at high temperature (40±2 °C) and relative humidity (75±5%) in spite of vitamin E sensitivity to light, heat and oxygen. The entrapment efficiency of NCs prepared at pilot scale was 97% at the beginning of the stability study, and became (95%, 59%) after 3 and 6 months of storage, respectively. These values at lab-scale were (98%, 96%, and 89%) at time zero and after 3 and 6 months of storage, respectively. This confirms the ability of vitamin E encapsulation to preserve its stability, which is one major goal of our work. Lyophilization of the optimized formula at lab-scale was also performed. Four types of cryoprotectants were tested (poly(vinyl pyrrolidone), sucrose, mannitol, and glucose). Freeze-dried NCs prepared with sucrose were found acceptable. The other lyophilized NCs obtained at different conditions presented large aggregates.

  14. Tube-side mass transfer for hollow fibre membrane contactors operated in the low Graetz range.

    Science.gov (United States)

    Wang, C Y; Mercer, E; Kamranvand, F; Williams, L; Kolios, A; Parker, A; Tyrrel, S; Cartmell, E; McAdam, E J

    2017-02-01

    Transformation of the tube-side mass transfer coefficient derived in hollow fibre membrane contactors (HFMC) of different characteristic length scales (equivalent diameter and fibre length) has been studied when operated in the low Graetz range (Gzlow Gz range, mass transfer is generally described by the Graetz problem (Sh=3.67) which assumes that the concentration profile comprises a constant shape over the fibre radius. In this study, it is experimentally evidenced that this assumption over predicts mass transfer within the low Graetz range. Furthermore, within the low Gz range (below 2), a proportional relationship between the experimentally determined mass transfer coefficient (Kov ) and the Graetz number has been identified. For Gz numbers below 2, the experimental Sh number approached unity, which suggests that mass transfer is strongly dependent upon diffusion. However, within this diffusion controlled region of mass transfer, tube-side fluid velocity remained important. For Gz numbers above 2, Sh could be satisfactorily described by extension to the Lévêque solution, which can be ascribed to the constrained growth of the concentration boundary layer adjacent to the fibre wall. Importantly this study demonstrates that whilst mass transfer in the low Graetz range does not explicitly conform to either the Graetz problem or classical Lévêque solution, it is possible to transform the experimentally derived overall mass transfer coefficient (Kov ) between characteristic length scales (dh and L). T h is was corroborated by comparison of the empirical relationship determined in this study (Sh=0.36Gz) with previously published studies operated in the low Gz range. This analysis provides important insight for process design when slow tube-side flows, or low Schmidt numbers (coincident with gases) constrain operation of hollow fibre membrane contactors to the low Gz range.

  15. Far-field Diffraction Properties of Annular Walsh Filters

    Directory of Open Access Journals (Sweden)

    Pubali Mukherjee

    2013-01-01

    Full Text Available Annular Walsh filters are derived from the rotationally symmetric annular Walsh functions which form a complete set of orthogonal functions that take on values either +1 or −1 over the domain specified by the inner and outer radii of the annulus. The value of any annular Walsh function is taken as zero from the centre of the circular aperture to the inner radius of the annulus. The three values 0, +1, and −1 in an annular Walsh function can be realized in a corresponding annular Walsh filter by using transmission values of zero amplitude (i.e., an obscuration, unity amplitude and zero phase, and unity amplitude and phase, respectively. Not only the order of the Walsh filter but also the size of the inner radius of the annulus provides an additional degree of freedom in tailoring of point spread function by using these filters for pupil plane filtering in imaging systems. In this report, we present the far-field amplitude characteristics of some of these filters to underscore their potential for effective use in several demanding applications like high-resolution microscopy, optical data storage, microlithography, optical encryption, and optical micromanipulation.

  16. Stratospheric Annular Modes Induced By Stationary Wave Forcing

    Science.gov (United States)

    Körnich, H.; Schmitz, G.

    The variability of the winter stratosphere shows distinguishable features in the north- ern and southern hemisphere. Since these differences are based on the different plan- etary waves of the underlying atmosphere, we explore the mechanism how stationary wave forcing in the troposphere can induce a stratospheric Annular Mode using a simple GCM. The model KMCM (Kühlungsborn Mechanistic Circulation Model) extends from the ground up to 60 km height and produces a reasonable winter climate. It takes into account the different large-scale wave forcings in the troposphere as prescribed pro- cesses. This allows us to examine the stratospheric Annular-Mode generation depend- ing on different wave forcings under perpetual January conditions. Principal com- ponent analysis is applied to identify the variability patterns of the geopotential and of the zonally averaged zonal wind. By this way, it is shown that the amplitude and composition of the orographic and thermal eddy forcing determines the stratospheric Annular Mode and the related downward propagation in the temperature field. Further model simplifications are introduced in order to understand the mechanism of the stratospheric AM-generation. Using a linear model version we illuminate the influence of the different wave forcing processes on the Annular Modes. Addition- ally, a constant-troposphere model is used to clarify the importance of transient and stationary waves. Finally, the Annular Mode is interpreted in terms of the dynamical coupling of the troposphere and stratosphere.

  17. Centrifugal acceleration in the magnetotail lobes

    Directory of Open Access Journals (Sweden)

    H. Nilsson

    2010-02-01

    Full Text Available Combined Cluster EFW and EDI measurements have shown that cold ion outflow in the magnetospheric lobes dominates the hydrogen ion outflow from the Earth's atmosphere. The ions have too low kinetic energy to be measurable with particle instruments, at least for the typical spacecraft potential of a sunlit spacecraft in the tenuous lobe plasmas outside a few RE. The measurement technique yields both density and bulk velocity, which can be combined with magnetic field measurements to estimate the centrifugal acceleration experienced by these particles. We present a quantitative estimate of the centrifugal acceleration, and the velocity change with distance which we would expect due to centrifugal acceleration. It is found that the centrifugal acceleration is on average outward with an average value of about of 5 m s−2. This is small, but acting during long transport times and over long distances the cumulative effect is significant, while still consistent with the relatively low velocities estimated using the combination of EFW and EDI data. The centrifugal acceleration should accelerate any oxygen ions in the lobes to energies observable by particle spectrometers. The data set also put constraints on the effectiveness of any other acceleration mechanisms acting in the lobes, where the total velocity increase between 5 and 19 RE geocentric distance is less than 5 km s−1.

  18. A Review of Biomedical Centrifugal Microfluidic Platforms

    Directory of Open Access Journals (Sweden)

    Minghui Tang

    2016-02-01

    Full Text Available Centrifugal microfluidic or lab-on-a-disc platforms have many advantages over other microfluidic systems. These advantages include a minimal amount of instrumentation, the efficient removal of any disturbing bubbles or residual volumes, and inherently available density-based sample transportation and separation. Centrifugal microfluidic devices applied to biomedical analysis and point-of-care diagnostics have been extensively promoted recently. This paper presents an up-to-date overview of these devices. The development of biomedical centrifugal microfluidic platforms essentially covers two categories: (i unit operations that perform specific functionalities, and (ii systems that aim to address certain biomedical applications. With the aim to provide a comprehensive representation of current development in this field, this review summarizes progress in both categories. The advanced unit operations implemented for biological processing include mixing, valving, switching, metering and sequential loading. Depending on the type of sample to be used in the system, biomedical applications are classified into four groups: nucleic acid analysis, blood analysis, immunoassays, and other biomedical applications. Our overview of advanced unit operations also includes the basic concepts and mechanisms involved in centrifugal microfluidics, while on the other hand an outline on reported applications clarifies how an assembly of unit operations enables efficient implementation of various types of complex assays. Lastly, challenges and potential for future development of biomedical centrifugal microfluidic devices are discussed.

  19. Demonstration of Caustic-Side Solvent Extraction with Optimized Solvent in the 2-cm Centrifugal Contactor Apparatus Using Dissolved Salt Cake from Tank 37H

    Energy Technology Data Exchange (ETDEWEB)

    Norato, M.A.

    2002-10-21

    A solvent extraction process for removal of cesium from alkaline solutions has been developed utilizing a novel solvent invented at the Oak Ridge National Laboratory (ORNL). This solvent consists of a calix[4]arene-crown-6 extractant (BOBCalix) dissolved in an inert hydrocarbon matrix (Isopar(R) L). An alkylphenoxy alcohol modifier added to the solvent enhances the extraction power of the calixarene and prevents the formation of a third phase. An additional additive, trioctylamine (TOA), improves stripping performance and mitigates the effects of any surfactants present in the feed stream. The solvent extraction process was successfully demonstrated with actual SRS HLW supernate during testing performed at SRTC in FY-2001. However, the solvent system has recently been optimized to enhance extractant solubility in the diluent and increase suppressor concentration. The results of the optimized solvent performance in tests using the same SRS composite waste supernate as was used FY-20 01 are described in another report.

  20. Demonstration of Caustic-Side Solvent Extraction with Optimized Solvent in the 2-cm Centrifugal Contactor Apparatus Using Dissolved Salt Cake from Tank 37H

    Energy Technology Data Exchange (ETDEWEB)

    Norato, M.A.

    2003-01-06

    Researchers successfully demonstrated the chemistry of the Caustic-Side Solvent Extraction (CSSX) flow sheet with optimized solvent. This represents the third such process demonstration using actual Savannah River Site (SRS) high level waste (HLW). The present test differed from previous studies in the use of radioactive waste derived from Tank 37H dissolved salt cake, as opposed to supernate solutions used in previous demonstrations.

  1. Multifold Laser Resonator for Annular Gain Media.

    Science.gov (United States)

    Duncan, Arlene

    Available from UMI in association with The British Library. A pair of spherical mirrors enclosing an off-axis beam in a hyperboloidal ray trajectory describes a Herriott Cell. Placed inside a linear Fabry Perot resonator, a multifold laser resonator is formed. By considering this resonator when coupled to a coaxial, annular geometry, RF discharge excited CO_2 gain media in a sealed-off configuration, this thesis aims to formulate the scaling laws and characterise the main features of these devices. To help establish a design baseline and to allow the determination of practical results, the scaling laws are developed with an (arbitrary) limit on the physical size of the laser module of 100 x 10 x 10cm. Within this size, design algorithms demonstrate the limitation on scaling power to about 460W. Output beam characteristics are investigated for a range of multifold lasers to determine the effects the choice of design parameters has and the predicted TEM _{00} output expected. All incongruities are found to be primarily dependent on whether or not the beam traverses the complete Herriott Cell, but more directly on the radial gain and refractive index variations present in the gain medium. In terms of polarization, image rotation and astigmatism, the Cell has been analysed to determine the non-planar influence. Theoretical and experimental results tie in with the conclusions from the previous observations. The use of tolerance equations and a study of deviations in beam spot positions on the mirrors under misalignments illustrates; dependence on electrode dimensions; greatest sensitivity to Cell mirror tilts; and a shift in the ray envelope cross-section from circular to elliptical on all resonator adjustments. At all stages results are compared with existing multifold lasers and other lasers with similar output powers. As a whole the thesis demonstrates the potential of these lasers in the medium power range as sealed-off devices with excellent mode quality. Increased

  2. Annular lupus vulgaris: an unusual case undiagnosed for five years.

    Science.gov (United States)

    Gönül, Müzeyyen; Kiliç, Arzu; Külcü Cakmak, Seray; Gül, Ulker; Koçak, Oğuzhan; Demiriz, Murat

    2007-01-01

    Tuberculosis is still a serious problem in both developing and developed countries. It is often confused with various cutaneous disorders both clinically and histopathologically.A 46-year-old woman attended our clinic with progressive, asymptomatic, annular skin lesions on her right upper extremity for 5 years. She had received many different therapies for these lesions at other institutions previously but these medications were not effective and the lesions deteriorated. On dermatological examination, well-demarcated, irregular bordered, violaceous colored, elevated and crusted annular lesions on her right hand dorsum and forearm were observed. She was diagnosed as having lupus vulgaris clinically and histopathologically. Antituberculosis therapy was administered and regression of the lesions started in the second week of medication.We report a case of long-standing, undiagnosed and uncommon, annular form of lupus vulgaris. We want to stress that clinical and histopathological findings are still important for the diagnosis of cutaneous tuberculosis.

  3. Portal Annular Pancreas: A Rare and Overlooked Anomaly

    Science.gov (United States)

    Mittal, Puneet; Gupta, Ranjana; Mittal, Amit; Ahmed, Arshad

    2017-01-01

    Summary Background Portal annular pancreas is a rare pancreatic developmental anomaly which is often overlooked at imaging, and often diagnosed retrospectively when it is detected incidentally at the time of surgery. Although the anomaly itself is asymptomatic, it becomes important in cases where pancreatic resection/anastomosis is planned, because of varying ductal anatomy, risk of ductal injury and increased risk of postoperative pancreatic fistula formation. Case Report We present imaging findings in a case of portal annular pancreas in a 45-year-old male patient. Conclusions Portal annular pancreas is a rare and often neglected pancreatic anomaly due to a lack of awareness of this entity. With the advent of MDCT and MRI, accurate preoperative diagnosis of this condition is possible.

  4. Vibration Analysis of Annular Sector Plates under Different Boundary Conditions

    Directory of Open Access Journals (Sweden)

    Dongyan Shi

    2014-01-01

    Full Text Available An analytical framework is developed for the vibration analysis of annular sector plates with general elastic restraints along each edge of plates. Regardless of boundary conditions, the displacement solution is invariably expressed as a new form of trigonometric expansion with accelerated convergence. The expansion coefficients are treated as the generalized coordinates and determined using the Rayleigh-Ritz technique. This work allows a capability of modeling annular sector plates under a variety of boundary conditions and changing the boundary conditions as easily as modifying the material properties or dimensions of the plates. Of equal importance, the proposed approach is universally applicable to annular sector plates of any inclusion angles up to 2π. The reliability and accuracy of the current method are adequately validated through numerical examples.

  5. Inverted annular flow heat transfer in a natural circulation loop

    Energy Technology Data Exchange (ETDEWEB)

    Ozawa, M.; Umekawa, H.; Shiba, Y.; Yano, T. [Kansai Univ., Osaka (Japan)

    1998-07-01

    Gravity-feed reflooding experiment was conducted in a natural circulation loop of liquid nitrogen. The cooling curve of high temperature tube wall had a characteristic feature, i.e. initial rapid cooling with steam binding, relatively long-time plateau, gradual decrease with or without flow oscillation, and final drastic decrease during quenching process. Such phenomena had close relationship to the heated wall dynamics and heating power transient. To provide fundamental understanding on the present phenomena, the heat transfer data in inverted annular and dispersed flows were obtained under steady or oscillatory flow condition. The experimental data suggested that the heat transfer coefficient in the inverted annular or dispersed flow regimes is a slightly increasing function of heat flux but significantly depended on the tube diameter. The flow oscillation deteriorated heat transfer slightly in the inverted annular and dispersed flow regimes but significantly in the quenching process.

  6. The effect of surfactants on the ozonation of o-cresol in aqueous solutions in a rotating packed contactor.

    Science.gov (United States)

    Ku, Young; Ji, Yan-Shiun; Chen, Hua-Wei; Chou, Yiang-Chen; Chang, Ching-Yuan

    2010-02-01

    Steady-state dissolved ozone concentrations were maintained relatively constant for experiments on ozone dissolution conducted in the presence of various amounts of sodium dodecyl sulphate (SDS) and Triton X-100 (TX-100), an anionic surfactant and a nonionic surfactant, respectively. Ozonation in a rotating packed contactor has been shown to be feasible for achieving nearly complete decomposition of o-cresol within about 10 minutes of reaction time for most experiments conducted. The temporal decomposition behaviour of o-cresol in aqueous solution by ozonation was described by a two-step pseudo-first-order reaction kinetics. Even though the presence of SDS and TX-100 slightly affected the decomposition rate constant of o-cresol by ozonation in the rotating packed contactor, the mineralization of total organic carbon was apparently reduced with the addition of SDS and TX-100.

  7. Membrane contactor/separator for an advanced ozone membrane reactor for treatment of recalcitrant organic pollutants in water

    Science.gov (United States)

    Kit Chan, Wai; Jouët, Justine; Heng, Samuel; Lun Yeung, King; Schrotter, Jean-Christophe

    2012-05-01

    An advanced ozone membrane reactor that synergistically combines membrane distributor for ozone gas, membrane contactor for pollutant adsorption and reaction, and membrane separator for clean water production is described. The membrane reactor represents an order of magnitude improvement over traditional semibatch reactor design and is capable of complete conversion of recalcitrant endocrine disrupting compounds (EDCs) in water at less than three minutes residence time. Coating the membrane contactor with alumina and hydrotalcite (Mg/Al=3) adsorbs and traps the organics in the reaction zone resulting in 30% increase of total organic carbon (TOC) removal. Large surface area coating that diffuses surface charges from adsorbed polar organic molecules is preferred as it reduces membrane polarization that is detrimental to separation.

  8. Analysis of Secondary Flows in Centrifugal Impellers

    Directory of Open Access Journals (Sweden)

    Brun Klaus

    2005-01-01

    Full Text Available Secondary flows are undesirable in centrifugal compressors as they are a direct cause for flow (head losses, create nonuniform meridional flow profiles, potentially induce flow separation/stall, and contribute to impeller flow slip; that is, secondary flows negatively affect the compressor performance. A model based on the vorticity equation for a rotating system was developed to determine the streamwise vorticity from the normal and binormal vorticity components (which are known from the meridional flow profile. Using the streamwise vorticity results and the small shear-large disturbance flow method, the onset, direction, and magnitude of circulatory secondary flows in a shrouded centrifugal impeller can be predicted. This model is also used to estimate head losses due to secondary flows in a centrifugal flow impeller. The described method can be employed early in the design process to develop impeller flow shapes that intrinsically reduce secondary flows rather than using disruptive elements such as splitter vanes to accomplish this task.

  9. Possible segregation caused by centrifugal titanium casting.

    Science.gov (United States)

    Watanabe, K; Okawa, S; Kanatani, M; Nakano, S; Miyakawa, O; Kobayashi, M

    1996-12-01

    The possibility of the segregation under solidification process using a centrifugal casting machine was investigated using an electron probe microanalyzer with elemental distribution map, line analysis and quantitative analysis. When a very small quantity of platinum was added to local molten titanium during the casting process, macroscopic segregation was observed under conditions of density difference of 0.1 g/cm3 at the most, confirming that the centrifugal force of the casting machine is extremely strong. When a Ti-6Al-4V alloy was cast, however, no macroscopic segregation was observed. The centrifugal force of the casting machine examined in the present study hardly results in the body-force segregation in this titanium alloy.

  10. Mathematical Model of Combustion in Blunt Annular Ceramic Burner

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The computer simulation of the combustion process in blast furnace (BF) stove has been studied by using the k-ε-g turbulent diffusion flame model. The combustion process in blunt annular ceramic burner was calculated by using the software. The profiles of gas and air velocity, temperature of the combustion products, concentration of the components, and the shape and length of the flame during combustion have been researched . Compared with the original annular ceramic burner, the new design of the blunt one improves the mixing of the gas and the air significantly, and shortened the length of the flame.

  11. Enhanced spontaneous emission rate in annular plasmonic nanocavities

    Science.gov (United States)

    Kroekenstoel, E. J. A.; Verhagen, E.; Walters, R. J.; Kuipers, L.; Polman, A.

    2009-12-01

    The spontaneous emission rate of erbium ions is enhanced by coupling to localized plasmonic resonances in subwavelength annular apertures in a Au film. The Er3+ ions, embedded in SiO2, are selectively located inside the apertures. The annular apertures act as nanocavities, enhancing the local density of optical states at the Er emission wavelength of 1.54 μm when the cavities are tuned to that wavelength. We show that this leads to an eightfold increase of the photoluminescence intensity, in conjunction with a 2.4-fold enhancement of the spontaneous emission rate.

  12. Polarization-independent waveguiding with annular photonic crystals.

    Science.gov (United States)

    Cicek, Ahmet; Ulug, Bulent

    2009-09-28

    A linear waveguide in an annular photonic crystal composed of a square array of annular dielectric rods in air is demonstrated to guide transverse electric and transverse magnetic modes simultaneously. Overlapping of the guided bands in the full band gap of the photonic crystal is shown to be achieved through an appropriate set of geometric parameters. Results of Finite-Difference Time-Domain simulations to demonstrate polarization-independent waveguiding with low loss and wavelength-order confinement are presented. Transmission through a 90 degrees bend is also demonstrated.

  13. Patch Type Granuloma Annulare Imitating Cutaneous T-Cell Lymphoma

    Directory of Open Access Journals (Sweden)

    Seval Doğruk Kaçar

    2015-03-01

    Full Text Available Granuloma annulare (GA is a benign inflammatory skin disease with distinct clinical and histopathological findings. Patch type GA is described with erythematous patches beyond the classical clinical appearance and an interstitial pattern is observed without histopathologically granulomas with disseminated histiocytes among collagen bundles and vessels. Here we report 46 year old woman diagnosed as patch type GA after a punch biopsy performed from the annular bordered patches in belly area, which is a classical area for mycosis fungoides (MF evolution, and lesions increasingly spreading out within a 2 year period.

  14. Mitral-aortic annular enlargement: modification of Manouguian's technique

    Directory of Open Access Journals (Sweden)

    Costa Mario Gesteira

    2002-01-01

    Full Text Available We hereby present a technical modification for mitral-aortic annular enlargement. The mitral valve is replaced through the retro-septal approach, avoiding patches for left atrial roof closure. We report a mitral-aortic valve replacement in a patient whose original annuli would preclude adequate prostheses. The simultaneous annular enlargement may be necessary for avoiding patient-prosthesis mismatch and for reconstructing destroyed mitral and aortic annuli. The technique may minimize the risk of bleeding and of paravalvular leakage, using an approach well known to cardiac surgeons.

  15. Detection methods for centrifugal microfluidic platforms

    DEFF Research Database (Denmark)

    Burger, Robert; Amato, Letizia; Boisen, Anja

    2016-01-01

    Centrifugal microfluidics has attracted much interest from academia as well as industry, since it potentially offers solutions for affordable, user-friendly and portable biosensing. A wide range of so-called fluidic unit operations, e.g. mixing, metering, liquid routing, and particle separation......, have been developed and allow automation and integration of complex assay protocols in lab-on-a-disc systems. Besides liquid handling, the detection strategy for reading out the assay is crucial for developing a fully integrated system. In this review, we focus on biosensors and readout methods...... for the centrifugal microfluidics platform and cover optical as well as mechanical and electrical detection principles....

  16. Effect of polymer concentration on the structure and performance of PEI hollow fiber membrane contactor for CO2 stripping.

    Science.gov (United States)

    Naim, R; Ismail, A F

    2013-04-15

    A series of polyetherimide (PEI) hollow fiber membranes with various polymer concentrations (13-16 wt.%) for CO2 stripping process in membrane contactor application was fabricated via wet phase inversion method. The PEI membranes were characterized in terms of liquid entry pressure, contact angle, gas permeation and morphology analysis. CO2 stripping performance was investigated via membrane contactor system in a stainless steel module with aqueous diethanolamine as liquid absorbent. The hollow fiber membranes showed decreasing patterns in gas permeation, contact angle, mean pore size and effective surface porosity with increasing polymer concentration. On the contrary, wetting pressure of PEI membranes has enhanced significantly with polymer concentration. Various polymer concentrations have different effects on the CO2 stripping flux in which membrane with 14 wt.% polymer concentration showed the highest stripping flux of 2.7 × 10(-2)mol/m(2)s. From the performance comparison with other commercial membrane, it is anticipated that the PEI membrane has a good prospect in CO2 stripping via membrane contactor.

  17. Gauge design for electrical contactor parts%电工触头零件的检具设计

    Institute of Scientific and Technical Information of China (English)

    赵延岭

    2015-01-01

    概述了电工触头检具的概念、种类、使用要求、设计原则和结构.介绍了检具材料选择、认证验收标准和维护等.分析了检具功能部件设计及原则 ,通过 TeSys接触器触头检具设计 ,举例说明了如何设计检测直观准确、高效可靠的电工触头检具 ,利用设定的检具系统重复性和再现性数据统计表格来快速判断检具是否合格.结果表明 ,在电工触头批量生产中使用检具测量是一种准确、快捷和高效的方法.%In this paper the conceptions ,types ,requirements ,design principles and structure of electrical contactor gauge were introduced ;material selection ,acceptance criteria and maintenance were illustrated ;the design principles of gauge features was analyzed .Taking TeSys contactor gauge design as an example ,it was explained how to design intuitive ;accu-rate ,efficient and reliable electrical contact gauge .The results showed that the use of the gauge measurements in electrical contactor production is an accurate ,fast and efficient way .

  18. Wet air oxidation of formic acid using nanoparticle-modified polysulfone hollow fibers as gas-liquid contactors.

    Science.gov (United States)

    Hogg, Seth R; Muthu, Satish; O'Callaghan, Michael; Lahitte, Jean-Francois; Bruening, Merlin L

    2012-03-01

    Catalytic wet air oxidation (CWAO) using membrane contactors is attractive for remediation of aqueous pollutants, but previous studies of even simple reactions such as formic acid oxidation required multiple passes through tubular ceramic membrane contactors to achieve high conversion. This work aims to increase single-pass CWAO conversions by using polysulfone (PS) hollow fibers as contactors to reduce diffusion distances in the fiber lumen. Alternating adsorption of polycations and citrate-stabilized platinum colloids in fiber walls provides catalytically active PS hollow fibers. Using a single PS fiber, 50% oxidation of a 50 mM formic acid feed solution results from a single pass through the fiber lumen (15 cm length) with a solution residence time of 40 s. Increasing the number of PS fibers to five while maintaining the same volumetric flow rate leads to over 90% oxidation, suggesting that further scale up in the number of fibers will facilitate high single pass conversions at increased flow rates. The high conversion compared to prior studies with ceramic fibers stems from shorter diffusion distances in the fiber lumen. However, the activity of the Pt catalyst is 20-fold lower than in previous ceramic fibers. Focusing the Pt deposition near the fiber lumen and limiting pore wetting to this region might increase the activity of the catalyst.

  19. Multi-functional annular fairing for coupling launch abort motor to space vehicle

    Science.gov (United States)

    Camarda, Charles J. (Inventor); Scotti, Stephen J. (Inventor); Buning, Pieter G. (Inventor); Bauer, Steven X. S. (Inventor); Engelund, Walter C. (Inventor); Schuster, David M. (Inventor)

    2011-01-01

    An annular fairing having aerodynamic, thermal, structural and acoustic attributes couples a launch abort motor to a space vehicle having a payload of concern mounted on top of a rocket propulsion system. A first end of the annular fairing is fixedly attached to the launch abort motor while a second end of the annular fairing is attached in a releasable fashion to an aft region of the payload. The annular fairing increases in diameter between its first and second ends.

  20. Centrifugal Sieve for Size-Segregation/ Beneficiation of Regolith Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Utilizing centrifugal force as the primary body-force, combined with both shearing flow and vibratory motion the proposed centrifugal-sieve separators can provide...

  1. Centrifugal Pump Experiment for Chemical Engineering Undergraduates

    Science.gov (United States)

    Vanderslice, Nicholas; Oberto, Richard; Marrero, Thomas R.

    2012-01-01

    The purpose of this paper is to describe a Centrifugal Pump Experiment that provided an experiential learning experience to chemical engineering undergraduates at the University of Missouri in the spring of 2010 in the Unit Operations Laboratory course. Lab equipment was used by senior students with computer-based data and control technology. In…

  2. APPLICATION ANALYSIS REPORT: RETECH PLASMA CENTRIFUGAL FURNACE

    Science.gov (United States)

    This document is an evaluation of the performance of the Retech, Inc. Plasma Centrifugal Furnace (PCF) and its applicability as a treatment for soils contaminated with organic and/or inorganic compounds. Both the technical and economic aspectsof the technology were examined. A...

  3. Performance of a Centrifugal Slurry Pump

    Directory of Open Access Journals (Sweden)

    Hawas Yahya Bajawi

    2014-02-01

    Full Text Available The aim of this study was to experimentally investigate the effect of speed, concentration and size of slurry on the performance of a centrifugal pump. For this purpose a facility was built where the performance of a centrifugal slurry pump was examined using aggregate slurry. Three sizes of slurry with three concentrations and at three impeller speeds were used for the performance investigations of a centrifugal slurry pump. As a reference performance the performance of centrifugal slurry pump was also tested with clean water. The performance of pump has been reported as variations of head, power and efficiency at various flow rates along with the system characteristics of the pump. The results reveal that the pump performance is grossly affected by the type of slurry, its concentration and size. Besides this the variation in speed also affects the performance as is observed in pumps with water. The maximum decrease in the head, with respect to clear water, at the operating point was found to be 47% for aggregate for size 20 mm, 15% concentration and 2600 rpm. The maximum decrement in efficiency at operating point for aggregate was found to be 47% for 4 mm size, 15% concentration and at 2200 rpm. The power increment requirement for aggregate was 9% for 4 mm size, 15% concentration and 2600 rpm.

  4. Predicting Droplet Formation on Centrifugal Microfluidic Platforms

    Science.gov (United States)

    Moebius, Jacob Alfred

    Centrifugal microfluidics is a widely known research tool for biological sample and water quality analysis. Currently, the standard equipment used for such diagnostic applications include slow, bulky machines controlled by multiple operators. These machines can be condensed into a smaller, faster benchtop sample-to-answer system. Sample processing is an important step taken to extract, isolate, and convert biological factors, such as nucleic acids or proteins, from a raw sample to an analyzable solution. Volume definition is one such step. The focus of this thesis is the development of a model predicting monodispersed droplet formation and the application of droplets as a technique for volume definition. First, a background of droplet microfluidic platforms is presented, along with current biological analysis technologies and the advantages of integrating such technologies onto microfluidic platforms. Second, background and theories of centrifugal microfluidics is given, followed by theories relevant to droplet emulsions. Third, fabrication techniques for centrifugal microfluidic designs are discussed. Finally, the development of a model for predicting droplet formation on the centrifugal microfluidic platform are presented for the rest of the thesis. Predicting droplet formation analytically based on the volumetric flow rates of the continuous and dispersed phases, the ratios of these two flow rates, and the interfacial tension between the continuous and dispersed phases presented many challenges, which will be discussed in this work. Experimental validation was completed using continuous phase solutions of different interfacial tensions. To conclude, prospective applications are discussed with expected challenges.

  5. Centrifugal Casting of Tubular Perovskite Membranes

    NARCIS (Netherlands)

    Mertins, Frederic H.B.; Kruidhof, Henk; Bouwmeester, Henny J.M.

    2005-01-01

    Dense tubular membranes were produced by centrifugal casting of an aqueous suspension, containing powder particles of the mixed-conducting perovskite La0.5Sr0.5CoO3−δ and a dispersant. The resulting green bodies were dried and sintered to produce tubes with a maximum length of 12 cm, having a relat

  6. Evaluation of an improved centrifugal casting machine.

    Science.gov (United States)

    Donovan, T E; White, L E

    1985-05-01

    A Type III gold alloy, a silver-palladium alloy, and a base metal alloy were cast in two different centrifugal casting machines. With the number of complete cast mesh squares as an indicator of castability, the Airspin casting machine produced superior castings with all three alloys. The base metal alloy produced the greatest number of complete squares with both casting machines.

  7. Pressure distribution in centrifugal dental casting.

    Science.gov (United States)

    Nielsen, J P

    1978-02-01

    Equations are developed for liquid metal pressure in centrifugal dental casting, given the instantaneous rotational velocity, density, and certain dimensions of the casting machine and casting pattern. A "reference parabola" is introduced making the fluid pressure concept more understandable. A specially designed specimen demonstrates experimentally the reference parabola at freezing.

  8. Modeling and control of water disinfection process in annular photoreactors

    NARCIS (Netherlands)

    Keesman, K.J.; Vries, D.; Mourik, van S.; Zwart, H.

    2007-01-01

    Abstract¿ As an alternative or addition to complex physical modeling, in this paper transfer function models of the disinfection process in annular photoreactors under different flow conditions are derived. These transfer function models allow an analytical evaluation of the system dynamics and the

  9. Modelling of water disinfection process in annular photoreactors

    NARCIS (Netherlands)

    Keesman, K.J.; Parasoglou, M.; Vries, D.

    2006-01-01

    As an alternative or addition to complex physical modelling, in this paper transfer function models of the disinfection process in annular photoreactors under different flow conditions are derived. These transfer function models allow an analytical evaluation of the system dynamics and the control s

  10. Modeling and control of water disinfection process in annular photoreactors

    NARCIS (Netherlands)

    Keesman, K.J.; Vries, D.; Mourik, van S.; Zwart, H.J.; Tzafestas, S.

    2007-01-01

    As an alternative or addition to complex physical modeling, in this paper transfer function models of the disinfection process in annular photoreactors under different flow conditions are derived. These transfer function models allow an analytical evaluation of the system dynamics and the control st

  11. Design curves for circular and annular duct silencers

    Science.gov (United States)

    Watson, Willie R.; Ramakrishnan, R.

    1989-01-01

    Conventional models of sound propagation between porous walls (Scott, 1946) are adapted in order to calculate design curves for the lined circular and annular-duct silencers used in HVAC systems. The derivation of the governing equations is outlined, and results for two typical cases are presented graphically. Good agreement with published experimental data is demonstrated.

  12. Annular-cladding erbium doped multicore fiber for SDM amplification.

    Science.gov (United States)

    Jin, Cang; Ung, Bora; Messaddeq, Younès; LaRochelle, Sophie

    2015-11-16

    We propose and numerically investigate annular-cladding erbium doped multicore fibers (AC-EDMCF) with either solid or air hole inner cladding to enhance the pump power efficiency in optical amplifiers for spatial division multiplexing (SDM) transmission links. We first propose an all-glass fiber in which a central inner cladding region with a depressed refractive index is introduced to confine the pump inside a ring-shaped region overlapping the multiple signal cores. Through numerical simulations, we determine signal core and annular pump cladding parameters respecting fabrication constraints. We also propose and examine a multi-spot injection scheme for launching the pump in the annular cladding. With this all-glass fiber with annular cladding, our results predict 10 dB increase in gain and 21% pump power savings compared to the standard double cladding design. We also investigate a fiber with an air hole inner cladding to further enhance the pump power confinement and minimize power leaking into the inner cladding. The results are compared to the all-glass AC-EDMCF.

  13. Fluxon dynamics in long annular Josephson tunnel junctions

    DEFF Research Database (Denmark)

    Martucciello, N.; Mygind, Jesper; Koshelets, V.P.

    1998-01-01

    Single-fluxon dynamics has been experimentally investigated in high-quality Nb/Al-AlOx/Nb annular Josephson tunnel junctions having a radius much larger than the Josephson penetration depth. Strong evidence of self-field effects is observed. An external magnetic field in the barrier plane acts...

  14. Life Testing of the Hollow Cathode Plasma Contactor for the ProSEDS Mission

    Science.gov (United States)

    Vaughn, Jason A.; Schneider, Todd A.; Finckenor, Miria M.; Munafo, Paul M. (Technical Monitor)

    2001-01-01

    The Propulsive Small Expendable Deployer System (ProSEDS) mission is designed to provide an on-orbit demonstration of the electrodynamic propulsion capabilities of tethers in space. The ProSEDS experiment will be a secondary payload on a Delta 11 unmanned expendable booster. A 5-km conductive tether is attached to the Delta 11 second stage and collects current from the low Earth orbit (LEO) plasma. A hollow cathode plasma contactor emits the collected electrons from the Delta II, completing the electrical circuit with the ambient plasma. The current flowing through the tether generates thrust based on the Lorentz Force Law. The thrust will be generated opposite to the velocity vector, slowing down the spacecraft and causing it to de-orbit in approximately 14 days compared to the normal 6 months. A 10-km non-conductive tether is between the conductive tether and an endmass containing several scientific instruments. The ProSEDS mission lifetime was set at I day because most of the primary objectives can be met in that time. The extended ProSEDS mission will be for as many days as possible, until the Delta 11 second stage burns up or the tether is severed by a micrometeoroid or space debris particle. The Hollow Cathode Plasma Contactor (HCPC) unit has been designed for a 12-day mission. Because of the science requirements to measure the background ambient plasma, the HCPC must operate on a duty cycle. Later in the ProSEDS mission, the HCPC is operated in a manner to allow charging of the secondary battery. Due to the unusual operating requirements by the ProSEDS mission, a development unit of the HCPC was built for thorough testing. This developmental unit was tested for a simulated ProSEDS mission, with measurements of the ability to start and stop during the duty cycle. These tests also provided valuable data for the ProSEDS software requirements. Qualification tests of the HCPC flight hardware are also discussed.

  15. Evolution of microstructure in centrifugal cast Al-Cu alloy

    Directory of Open Access Journals (Sweden)

    Sui Yanwei

    2010-02-01

    Full Text Available In this research, the effects of centrifugal radius and mould rotation speed on microstructure in centrifugal-cast Al-Cu alloy have been investigated. The results show that, with increase of the centrifugal radius or mould rotation speed, the grain size of centrifugal-cast Al-Cu alloy decreases gradually, while the content of white phases containing the Al2Cu precipitated from α-phase, divorced eutectic and regular eutectic microstructure increases, leading to higher Cu macrosegregation. The variation level of microstructure in centrifugal-cast Al-Cu alloy at 600 rpm of mould rotation speed is greater than that at 300 rpm.

  16. Recovery of methane from anaerobic process effluent using poly-di-methyl-siloxane membrane contactors.

    Science.gov (United States)

    Cookney, J; Cartmell, E; Jefferson, B; McAdam, E J

    2012-01-01

    This paper demonstrates the potential for recovering dissolved methane from low temperature anaerobic processes treating domestic wastewater. In the absence of methane recovery, ca. 45% of the produced methane is released as a fugitive emission which results in a net carbon footprint of -0.47 kg CO(2e) m(-3). A poly-di-methyl-siloxane (PDMS) membrane contactor was applied to support sweep gas desorption of dissolved methane using nitrogen. The dense membrane structure controlled gaseous mass transfer thus recovery was maximised at low liquid velocities. At the lowest liquid velocity, V(L), of 0.0025 m s(-1), 72% of the dissolved methane was recovered. A vacuum was also trialled as an alternative to sweep-gas operation. At vacuum pressures below 30 mbar, reasonable methane recovery was observed at an intermediate V(L) of 0.0056 m s(-1). Results from this study demonstrate that dissolved methane recovery could increase net electrical production from low temperature anaerobic processes by ca. +0.043 kWh(e) m(-3) and reduce the net carbon footprint to +0.01 kg CO(2e) m(-3). However, further experimental work to optimise the gas-side hydrodynamics is required as well as validation of the long-term impacts of biofouling on process performance.

  17. Vacuum interrupter, high reliability component of distribution switches, circuit breakers and contactors

    Institute of Scientific and Technical Information of China (English)

    SLADE Paul G.; LI Wang-pei; MAYO Stephen; SMITH R.Kirkland; TAYLOR Erik D.

    2007-01-01

    The use of vacuum interrupters (VIs) as the current interruption component for switches, circuit breakers, reclosers and contactors operating at distribution voltages has escalated since their introduction in the mid-1950's. This electrical product has developed a dominating position for switching and protecting distribution circuits. VIs are even being introduced into switching products operating at transmission voltages. Among the reasons for the VI's popularity are its compactness, its range of application, its low cost, its superb electrical and mechanical life and its ease of application. Its major advantage is its well-established reliability. In this paper we show how this reliability has been achieved by design, by mechanical life testing and by electrical performance testing. We introduce the "sealed for life" concept for the VI's integrity. We discuss this in terms of what is meant by a practical leak rate for VIs with a life of over 30 years. We show that a simple high voltage withstand test is an easy and effective method for monitoring the long-term vacuum integrity. Finally we evaluate the need for routine inspection of this electrical product when it is used in adverse ambient environments.

  18. Continuous treatment of coloured industry wastewater using immobilized Phanerochaete chrysosporium in a rotating biological contactor reactor.

    Science.gov (United States)

    Pakshirajan, Kannan; Kheria, Sumeet

    2012-06-30

    Coloured industry wastewaters often contain dyes and other toxic ingredients, and, therefore, pose serious threat to the receiving environment. Among the available methods the eco-friendly biological method has gained maximum attention due to its many advantages over the traditional methods. In the present study, continuous biological treatment of coloured wastewater from a textile dyeing industry was investigated using the white rot fungus Phanerochaete chrysosporium in a rotating biological contactor (RBC) reactor. The raw wastewater was diluted with an equal volume of either distilled water or media containing glucose at varying concentrations to study its effect on the decolourization process. Results revealed that the wastewater could be decolourized to an extent of more than 64% when diluted with media containing glucose; and, a maximum decolourization efficiency of 83% was obtained with 10 g/l glucose concentration. COD removal efficiencies were also found to be consistent with the decolourization efficiencies of the wastewaters. Further, the results were correlated with the enzyme activities of manganese peroxidase (MnP) and lignin peroxidase (LiP) by the fungus, which were found to play some significant role in decolourization of the wastewater. Results of replacing the costly carbon source glucose in the decolourization media with the more cheap molasses, however, revealed very high COD removal efficiency, but low decolourization efficiency of the industry wastewater.

  19. A portable membrane contactor sampler for analysis of noble gases in groundwater.

    Science.gov (United States)

    Matsumoto, Takuya; Han, Liang-Feng; Jaklitsch, Manfred; Aggarwal, Pradeep K

    2013-01-01

    To enable a wider use of dissolved noble gas concentrations and isotope ratios in groundwater studies, we have developed an efficient and portable sampling device using a commercially available membrane contactor. The device separates dissolved gases from a stream of water and collects them in a small copper tube (6 mm in diameter and 100 mm in length with two pinch-off clamps) for noble gas analysis by mass spectrometry. We have examined the performance of the sampler using a tank of homogeneous water prepared in the laboratory and by field testing. We find that our sampling device can extract heavier noble gases (Ar, Kr, and Xe) more efficiently than the lighter ones (He and Ne). An extraction time of about 60 min at a flow rate of 3 L/min is sufficient for all noble gases extracted in the sampler to attain equilibrium with the dissolved phase. The extracted gas sample did not indicate fractionation of helium ((3) He/(4) He) isotopes or other noble gas isotopes. Field performance of the sampling device was tested using a groundwater well in Vienna and results were in excellent agreement with those obtained from the conventional copper tube sampling method.

  20. Bacterial community dynamics in a rotating biological contactor treating 2-fluorophenol-containing wastewater.

    Science.gov (United States)

    Duque, Anouk F; Bessa, Vânia S; Castro, Paula M L

    2014-01-01

    One of the main factors affecting the performance of rotating biological contactors (RBC) is the biofilm characteristics. Therefore, a deep understanding of the microbial population dynamics and structure of the biofilm is mandatory if optimization of organic matter and nutrients removal is targeted. This study focused on the effects of organic shock loads of 2-fluorophenol (2-FP) on the microbial diversity present in an RBC biofilm. The RBC was seeded with activated sludge from a conventional wastewater treatment plant and was operated during 496 days. During the first 126 days, the RBC was subjected to intermittent 2-FP shocks of 25 mg l(-1) and no degradation occurred. Therefore, the reactor was subsequently augmented with a 2-FP-degrading strain (FP1). Afterwards, the RBC had a stable performance when subjected to 2-FP shocks up to 50 mg l(-1) and to a starvation period, as indicated by removal of the compound. Denaturing gradient gel electrophoresis (DGGE) revealed large shifts in microbial communities present in the first and fifth stages, although no clear relation between the sample collection time and spatial factor was found. Phylogenetic affiliation of some predominant members was assessed by direct sequencing of correspondent DGGE bands. Affiliations to α-, β- and δ-Proteobacteria were found. Several bacterial strains isolated from the reactor showed capacity for 2-FP degradation. Strain FP1 was successfully recovered from the biofilm by plating and by DGGE, reinforcing that bioaugmentation was successfully achieved.

  1. Degradation of phenolics, nitrogen-heterocyclics and polynuclear aromatic hydrocarbons in a rotating biological contactor.

    Science.gov (United States)

    Jeswani, Hansa; Mukherji, Suparna

    2012-05-01

    The degradation of phenolics, heterocyclics and polynuclear aromatic hydrocarbons (PAHs) in a synthetic biomass gasifier wastewater with average COD of 1388 mg/L was studied in a three stage rotating biological contactor (RBC) using the pyrene degrader, Exiguobacterium aurantiacum and activated sludge consortia (1:3 v/v). As the organic loading rate (OLR) was varied from 3.3 to 14 g/m(2)/d, the COD removal ranged from 63.3% to 92.6%. Complete removal of all the constituents was observed at the lowest OLR of 3.3g/m(2)/d. At 24h hydraulic retention time (HRT) and OLR of 6.6g/m(2)/d complete removal of pyridine, quinoline and benzene and 85-96% removal of phenol, naphthalene, phenanthrene, fluoranthene and pyrene was observed. E. aurantiacum was found to be the dominant bacteria in the biofilm. Clark's model provided good fits to data for all the three stages of the RBC.

  2. Energy-efficient treatment of organic wastewater streams using a rotatable bioelectrochemical contactor (RBEC).

    Science.gov (United States)

    Cheng, Ka Yu; Ho, Goen; Cord-Ruwisch, Ralf

    2012-12-01

    A membraneless bioelectrochemical system - rotatable bio-electrochemical contactor (RBEC) consists of an array of rotatable electrode disks was developed to convert the chemical energy from wastewater organics (acetate) directly into electricity. Each rotatable electrode disk had an upper-air exposing and a lower-water submerging halves. Intermittent rotation (180°) enabled each halve to alternately serve as anode and cathode. Removal of chemical oxygen demand (COD) was increased by 15% (from 0.79 to 0.91 kg COD m(-3) d(-1)) by allowing electron flow from the lower to the upper disk halves. Coupling with a potentiostat could alleviate cathodic limitation and increased COD removal to 1.32 kg COD m(-3) day(-1) (HRT 5h). About 40% of the COD removed was via current, indicating that the biofilm could use the lower half disk as electron acceptor. The RBEC removed COD more energy-efficiently than conventional activated sludge processes as active aeration is not required (0.47 vs. 0.7-2.0 kW h kg COD(-1)).

  3. Rotating biological contactor reactor with biofilm promoting mats for treatment of benzene and xylene containing wastewater.

    Science.gov (United States)

    Sarayu, K; Sandhya, S

    2012-12-01

    A novel rotating biological contactor (RBC) bioreactor immobilized with microorganisms was designed to remove volatile organic compounds (VOC), such as benzene and xylene from emissions, and its performance was investigated. Gas-phase VOCs stripped by air injection were 98 % removed in the RBC when the superficial air flow rate was 375 ml/h (1,193 and 1,226 mg/l of benzene and xylene, respectively). The maximum removal rate was observed to be 1,007 and 1,872 mg/m(3)/day for benzene and xylene, respectively. The concentration profile of benzene and xylene along the RBC was dependent on the air flow rate and the degree of microbial adaptation. Air flow rate and residence time were found to be the most important operational parameters for the RBC reactor. By manipulating these operational parameters, the removal efficiency and capacity of the bioreactor could be enhanced. The kinetic constant K (s) demonstrated a linear relationship that indicated the maximum removal of benzene and xylene in RBC reactor. The phylogenic profile shows the presence of bacterium like Pseudomonas sp., Bacillus sp., and Enterococcus sp., which belonged to the phylum Firmicutes, and Proteobacteria that were responsible for the 98 % organic removal in the RBC.

  4. Liposome preparation using a hollow fiber membrane contactor--application to spironolactone encapsulation.

    Science.gov (United States)

    Laouini, A; Jaafar-Maalej, C; Sfar, S; Charcosset, C; Fessi, H

    2011-08-30

    In this study, we present a novel liposome preparation technique suitable for the entrapment of pharmaceutical and cosmetic agents. This new method uses a membrane contactor in a hollow fiber configuration. In order to investigate the process, key parameters influence on the liposome characteristics was studied. It has been established that the vesicle size distribution decreased with the organic phase pressure decrease, the phospholipid concentration decreases and the aqueous to organic phase volume ratio increases. Liposomes were filled with a hydrophobic drug model, spironolactone that could be used for a paediatric medication. The mean size of drug-free and drug-loaded liposomes was, respectively, 113 ± 4 nm and 123 ± 3 nm. The zeta potential of drug-free and drug-loaded liposomes was, respectively, -43 ± 0.7 mV and -23 ± 0.6 mV. High entrapment efficiency values were successfully achieved (93 ± 1.12%). Transmission electron microscopy images revealed nanometric sized and spherical shaped oligo-lamellar vesicles. The release profile showed a rapid and complete release within about 5h. Additionally, special attention was paid on process reproducibility and long term lipid vesicles stability. Results confirmed the robustness of the hollow fiber module based technique. Moreover, the technique is simple, fast and has a potential for continuous production of nanosized liposome suspensions at large scale.

  5. Surface Charging Controlling of the Chinese Space Station with Hollow Cathode Plasma Contactor

    Science.gov (United States)

    Jiang, Kai; Wang, Xianrong; Qin, Xiaogang; Yang, Shengsheng; Yang, Wei; Zhao, Chengxuan; Chen, Yifeng; Shi, Liang; Tang, Daotan; Xie, Kan

    2016-07-01

    A highly charged manned spacecraft threatens the life of an astronaut and extravehicular activity, which can be effectively reduced by controlling the spacecraft surface charging. In this article, the controlling of surface charging on Chinese Space Station (CSS) is investigated, and a method to reduce the negative potential to the CSS is the emission electron with a hollow cathode plasma contactor. The analysis is obtained that the high voltage (HV) solar array of the CSS collecting electron current can reach 4.5 A, which can be eliminated by emitting an adequate electron current on the CSS. The theoretical analysis and experimental results are addressed, when the minimum xenon flow rate of the hollow cathode is 4.0 sccm, the emission electron current can neutralize the collected electron current, which ensures that the potential of the CSS can be controlled in a range of less than 21 V, satisfied with safety voltage. The results can provide a significant reference value to define a flow rate to the potential controlling programme for CSS.

  6. Innovative use of membrane contactor as condenser for heat recovery in carbon capture.

    Science.gov (United States)

    Yan, Shuiping; Zhao, Shuaifei; Wardhaugh, Leigh; Feron, Paul H M

    2015-02-17

    The gas-liquid membrane contactor generally used as a nonselective gas absorption enhancement device is innovatively proposed as a condenser for heat recovery in liquid-absorbent-based carbon capture. The membrane condenser is used as a heat exchanger to recover the latent heat of the exiting vapor from the desorber, and it can help achieve significant energy savings when proper membranes with high heat-transfer coefficients are used. Theoretical thermodynamic analysis of mass and heat transfer in the membrane condensation system shows that heat recovery increases dramatically as inlet gas temperature rises and outlet gas temperature falls. The optimal split mass flow rate is determined by the inlet gas temperature and the overall heat-transfer coefficient in the condensation system. The required membrane area is also strongly dependent on the overall heat-transfer coefficient, particularly at higher inlet gas temperatures. Mass transfer across the membrane has an insignificant effect on heat transfer and heat recovery, suggesting that membrane wetting may not be an issue when a membrane condenser is used for heat recovery. Our analysis provides important insights into the energy recovery performance of the membrane condensation system as well as selection of operational parameters, such as split mass flow rate and membrane area, thickness, and thermal conductivity.

  7. Dispersion-free solvent extraction of Cr(VI) from acidic solutions using hollow fiber contactor.

    Science.gov (United States)

    Alguacil, Francisco J; Alonso, Manuel; Lopez, Félix A; Lopez-Delgado, Aurora; Padilla, Isabel

    2009-10-15

    The use of dispersión-free solvent extraction, through microporous hydrophobic membrane has been investigated. The hollow fiber contactor, with surface area of 1.4 m2 was used to extract Cr(VI) (0.005-0.12 g/L from aqueous sulphuric acidic media (pH 2.5-4.2 +/- 0.05). Several parameters such as extractant concentration, feed acidity and metal concentration in the initial aqueous solution were investigated. Results revealed that 15% v/v Cyanex 923 in Exxsol D-100 as organic phase and feed in the 2.5 pH range, gave optimum extraction (exceeding 95%) of Cr(VI) and it was possible to strip using 10 g/L hydrazine sulfate (also with recoveries exceeding 95%). In this step, Cr(VI) is immediately reduced to the less hazardous Cr(III) state. Results also showed that under the various experimental conditions, chromium(VI) extraction was rate-controlled by the interfacial reaction on the membrane surface. Typical overall mass transfer coefficients values are 4.2 x 10(-5) and 3.6 x 10(-6) cm/s for extraction and stripping operations, respectively.

  8. Experimental design and statistical analysis in Rotating Disc Contactor (RDC) column

    Science.gov (United States)

    Ismail, Wan Nurul Aiffah; Zakaria, Siti Aisyah; Noor, Nor Fashihah Mohd; Ariffin, Wan Nor Munirah

    2015-12-01

    The purpose of this paper is to examine the performance of the liquid-liquid extraction in Rotating Disc Contactor (RDC) Column that being used in industries. In this study, the performance of small diameter column RDC using the chemical system involving cumene/isobutryric asid/water are analyzed by the method of design of the experiments (DOE) and also Multiple Linear Regression (MLR). The DOE method are used to estimated the effect of four independent. Otherwise, by using Multiple Linear Regression (MLR) is to justify the relationship between the input variables and output variables and also to determine which variable are more influence for both output variable. The input variables for both method include rotor speed (Nr); ratio of flow (Fd); concentration of continuous inlet (Ccin); concentration of dispersed inlet (Cdin); interaction between Nr with Fd; interaction between Nr with Ccin; interaction Nr with Cdin. Meanwhile the output variables are concentration of continuous outlet (Ccout) and concentration of dispersed outlet (Cdout) on RDC column performance. By using this two method, we have two linear model represent two output of Ccout and Cdout for MLR. Lastly, the researcher want to determine which input variable that give more influence to output variable by using this two method. Based on the result, we obtained that rotor speed (Nr) more influence to dependent variable, Ccout and concentration of continuous inlet (Ccin) more influence to dependent variable, Cdout according the two method that was used.

  9. Macroscale and microscale analysis of Anammox in anaerobic rotating biological contactor

    Institute of Scientific and Technical Information of China (English)

    Yongtao Lv; Lei Wang; Xudong Wang; Yongzhe Yang; Zhiying Wang; Jie Li

    2011-01-01

    Inoculated with conventional anaerobic activated sludge,the Anammox process was successfully developed in an anaerobic rotating biological contactor (AnRBC) fed with a low ratio of C/N synthetic wastewater.Operated in a single point feed mode,the AnRBC removed 92.1% (n =126) of the influent N at the highest surface load of 12 g/(m2.day).The biomass increased by 25% and 17.1 g/(m2.day) of maximum N removal surface load was achieved by elevating flow rate with another feed point.Fluorescence in situ hybridization and polymerase chain reaction analysis indicated that the Anammox genus Candidatus Kuenenia stuttgartiensis dominated the community.Both Anammox and denitrifying activity were detected in biofilm by the application of microelectrodes.In the outer layer of the biofilm (0-2500 μm),nitrite and ammonium consumed simultaneously in a ratio of 1.12/1,revealing the occurrence of Anammox.In the inner layer (> 2500 μm),a decrease of nitrate was caused by denitrification in the absence of nitrite and ammonium.

  10. 交流接触器的常见故障及处理方法%Common failures and processing method of AC contactor

    Institute of Scientific and Technical Information of China (English)

    吕俊霞

    2012-01-01

      AC contactor is the most common application of a kind of electrical appliances in power system. The AC contactor common faults, the fault cause and the specific methods removing the faults are analyzed, including contactor inadequate suction, coil overheat or burn out, interphase short circuit and abnormal arcing etc..%  交流接触器是电力系统应用最普遍的一种电器。分析了交流接触器的常见故障、产生故障的原因及排除故障的具体方法,主要涉及接触器吸力不足、线圈过热或烧坏、相间短路、灭弧装置不正常灭弧等。

  11. Meridional Considerations of the Centrifugal Compressor Development

    Directory of Open Access Journals (Sweden)

    C. Xu

    2012-01-01

    Full Text Available Centrifugal compressor developments are interested in using optimization procedures that enable compressor high efficiency and wide operating ranges. Recently, high pressure ratio and efficiency of the centrifugal compressors require impeller design to pay attention to both the blade angle distribution and the meridional profile. The geometry of the blades and the meridional profile are very important contributions of compressor performance and structure reliability. This paper presents some recent studies of meridional impacts of the compressor. Studies indicated that the meridional profiles of the impeller impact the overall compressor efficiency and pressure ratio at the same rotational speed. Proper meridional profiles can improve the compressor efficiency and increase the overall pressure ratio at the same blade back curvature.

  12. Fault Detection and Isolation in Centrifugal Pumps

    DEFF Research Database (Denmark)

    Kallesøe, Carsten

    Centrifugal pumps are used in a variety of different applications, such as water supply, wastewater, and different industrial applications. Some pump installations are crucial for the applications to work. Failures can lead to substantial economic losses and can influence the life of many people...... when they occur. Therefore, detection of faults, if possible in an early stage, and isolation of their causes are of great interest. Especially fault detection, which can be used for predictive maintenance, can decrease working expenses and increase the reliability of the application in which the pump...... is placed. The topic of this work is Fault Detection and Identification in centrifugal pumps. Different approaches are developed with special focus on robustness. Robustness with respect to disturbances, unknown parts of the system, and parameter variations are considered. All developed algorithms...

  13. Analysis of Secondary Flows in Centrifugal Impellers

    OpenAIRE

    2005-01-01

    Secondary flows are undesirable in centrifugal compressors as they are a direct cause for flow (head) losses, create nonuniform meridional flow profiles, potentially induce flow separation/stall, and contribute to impeller flow slip; that is, secondary flows negatively affect the compressor performance. A model based on the vorticity equation for a rotating system was developed to determine the streamwise vorticity from the normal and binormal vorticity components (which are known from the me...

  14. Centrifugal shot blasting. Innovative technology summary report

    Energy Technology Data Exchange (ETDEWEB)

    1999-07-01

    At the US Department of Energy (DOE) Fernald Environmental Management Project (FEMP), the Facilities Closure and Demolition Projects Integrated Remedial Design/Remedial Action (RD/RA) work plan calls for the removal of one inch (1 in) depth of concrete surface in areas where contamination with technetium-99 has been identified. This report describes a comparative demonstration between two concrete removal technologies: an innovative system using Centrifugal Shot Blasting (CSB) and a modified baseline technology called a rotary drum planer.

  15. Predicting Droplet Formation on Centrifugal Microfluidic Platforms

    OpenAIRE

    Moebius, Jacob Alfred

    2015-01-01

    Centrifugal microfluidics is a widely known research tool for biological sample and water quality analysis. Currently, the standard equipment used for such diagnostic applications include slow, bulky machines controlled by multiple operators. These machines can be condensed into a smaller, faster benchtop sample-to-answer system.Sample processing is an important step taken to extract, isolate, and convert biological factors, such as nucleic acids or proteins, from a raw sample to an analyzabl...

  16. Centrifugal compressor design choices for chillers

    Energy Technology Data Exchange (ETDEWEB)

    Brasz, J.J. [United Technologies Carrier, New York, NY (United States)

    1999-07-01

    The use of centrifugal compressors in the air conditioning and refrigeration industry is currently limited to large water cooled chillers varying in size from about 0.5 to 6 MW cooling capacity. These systems are primarily used for comfort or process cooling applications. All systems try to chill relatively large amounts of indoor or process water by a few degrees Celsius in a refrigerant evaporator. The heat removed from the chilled water is released together with the heat of compression in a refrigerant condenser to cooling tower water, from where it is discharged to the atmosphere. Different centrifugal compressor design concepts are used by the various chiller manufacturers: single-stage versus multi-stage, vaneless versus vaned diffuser, hermetic versus open-drive motors, shrouded versus open impellers, fixed versus variable diffuser geometry, low- versus high-pressure refrigerant. This variability seems strange for a mature industry like the air conditioning and refrigeration industry. This paper will show that the reason for this variability is the product compromise between the various conflicting system requirements with respect to size, cost, efficiency and refrigerant choice. The different system applications of the chillers (e.g. comfort cooling in a equatorial region versus process cooling in a moderate climate zone) play another major role in selecting an optimal centrifugal compression concept. Some general recommendations will be given for applications where a clear choice can be made. (Author)

  17. Stable isotope enrichment using a plasma centrifuge

    Science.gov (United States)

    Krishnan, Mahadevan; Bures, Brian; Madden, Robert

    2012-10-01

    A primary goal of the Department of Energy's Isotope Development and Production for Research and Applications Program (Isotope Program) within the Office of Nuclear Physics (NP) is to produce isotopes that are in short supply in the U.S. and of which there exists no or insufficient domestic commercial production capability. A vacuum arc plasma centrifuge is a rigid rotor column of metal plasma in which centrifugal forces re-distribute ions radially according to their mass/charge ratio. Early work demonstrated rotation at 2 million rpm and separation of various stable isotopes. The spinning plasma column had a Gaussian flux profile, peaked on the rigid rotor axis. This work adopts a more efficient approach, with the plasma created as a hollow column, wherein the flux is concentrated at larger radii where the centrifugal action is highest. By tailoring the vacuum arc discharge geometry, the rotation rate can also be increased to ˜10 million rpm. Data from Cu, Al and other metal plasmas will be presented and discussed in light of enriched stable isotopes needed for research and medicine.

  18. Shallow water model for horizontal centrifugal casting

    Science.gov (United States)

    Boháček, J.; Kharicha, A.; Ludwig, A.; Wu, M.

    2012-07-01

    A numerical model was proposed to simulate the solidification process of an outer shell of work roll made by the horizontal centrifugal casting technique. Shallow water model was adopted to solve the 2D average flow dynamics of melt spreading and the average temperature distribution inside the centrifugal casting mould by considering the centrifugal force, Coriolis force, viscous force due to zero velocity on the mould wall, gravity, and energy transport by the flow. Additionally, a 1D sub-model was implemented to consider the heat transfer in the radial direction from the solidifying shell to the mould. The solidification front was tracked by fulfilling the Stefan condition. Radiative and convective heat losses were included from both, the free liquid surface and the outer wall of the mould. Several cases were simulated with the following assumed initial conditions: constant height of the liquid metal (10, 20, and 30 mm), uniform temperature of the free liquid surface (1755 K). The simulation results have shown that while the solidification front remained rather flat, the free surface was disturbed by waves. The amplitude of waves increased with the liquid height. Free surface waves diminished as the solidification proceeded.

  19. Based on prole ac contactor automatic assembly system research%基于Pro/E的交流接触器自动装配系统研究

    Institute of Scientific and Technical Information of China (English)

    王军浩; 杨丽华; 厉鹏

    2014-01-01

    Parts for ac contactor with proltoolklt application interface is provided for the secondary development of pro/engineer, the realization of ac contactor automatic assembly parts.Through automatic assembly can improve the design efficiency. shorten product development cycle.%针对交流接触器常用零件,利用Pro/TOOLKIT应用程序接口对Pro/ENGINEER进行二次开发,实现交流接触器零部件的自动装配。通过自动装配可以提高设计效率,缩短产品开发周期。

  20. Research on Environmental Adaptation Experiments for Contactors%接触器高原环境适应性试验研究

    Institute of Scientific and Technical Information of China (English)

    田华

    2015-01-01

    To enhance the capability and reliability of contactors in specific high altitude environment, this paper assesses the environmental adaptation experiments for contactors.%为了增强接触器在高原环境条件下的适应性能,提高接触器在高原特殊环境条件下的可靠性水平,特此提出对接触器应通过的环境适应性试验提出了考核评价。

  1. Production of annular flat-topped vortex beams

    Institute of Scientific and Technical Information of China (English)

    Jiannong Chen; Yongjiang Yu; Feifei Wang

    2011-01-01

    @@ A model of an annular flat-topped vortex beam based on multi-Gaussian superimposition is proposed. We experimentally produce this beam with a computer-generated hologram (CGH) displayed on a spatial light modulator (SLM). The power of the beam is concentrated on a single-ring structure and has an extremely strong radial intensity gradient. This beam facilitates various applications ranging from Sisyphus atom cooling to micro-particle trapping.%A model of an annular fiat-topped vortex beam based on multi-Gaussian superimposition is proposed. We experimentally produce this beam with a computer-generated hologram (CGH) displayed on a spatial light modulator (SLM). The power of the beam is concentrated on a single-ring structure and has an extremely strong radial intensity gradient. This beam facilitates various applications ranging from Sisyphus atom cooling to micro-particle trapping.

  2. Energy and Exergy Analysis of an Annular Thermoelectric Heat Pump

    Science.gov (United States)

    Kaushik, S. C.; Manikandan, S.; Hans, Ranjana

    2016-07-01

    In this paper, the concept of an annular thermoelectric heat pump (ATEHP) has been introduced. An exoreversible thermodynamic model of the ATEHP considering the Thomson effect in conjunction with Peltier, Joule and Fourier heat conduction has been investigated using exergy analysis. New expressions for dimensionless heating power, optimum current at the maximum energy, exergy efficiency conditions and dimensionless irreversibilities in the ATEHP are derived. The results show that the heating power, energy and exergy efficiency of the ATEHP are lower than the flat-plate thermoelectric heat pump. The effects of annular shape parameter ( S r = r 2 /r 1), dimensionless temperature ratio ( θ = T h /T c) and the electrical contact resistances on the heating power, energy/exergy efficiency of an ATEHP have been studied. This study will help in the designing of actual ATEHP systems.

  3. Wind generated rogue waves in an annular wave flume

    CERN Document Server

    Toffoli, A; Salman, H; Monbaliu, J; Frascoli, F; Dafilis, M; Stramignoni, E; Forza, R; Manfrin, M; Onorato, M

    2016-01-01

    We investigate experimentally the statistical properties of a wind-generated wave field and the spontaneous formation of rogue waves in an annular flume. Unlike many experiments on rogue waves, where waves are mechanically generated, here the wave field is forced naturally by wind as it is in the ocean. What is unique about the present experiment is that the annular geometry of the tank makes waves propagating circularly in an {\\it unlimited-fetch} condition. Within this peculiar framework, we discuss the temporal evolution of the statistical properties of the surface elevation. We show that rogue waves and heavy-tail statistics may develop naturally during the growth of the waves just before the wave height reaches a stationary condition. Our results shed new light on the formation of rogue waves in a natural environment.

  4. Axisymmetric buckling of laminated thick annular spherical cap

    Science.gov (United States)

    Dumir, P. C.; Dube, G. P.; Mallick, A.

    2005-03-01

    Axisymmetric buckling analysis is presented for moderately thick laminated shallow annular spherical cap under transverse load. Buckling under central ring load and uniformly distributed transverse load, applied statically or as a step function load is considered. The central circular opening is either free or plugged by a rigid central mass or reinforced by a rigid ring. Annular spherical caps have been analysed for clamped and simple supports with movable and immovable inplane edge conditions. The governing equations of the Marguerre-type, first order shear deformation shallow shell theory (FSDT), formulated in terms of transverse deflection w, the rotation ψ of the normal to the midsurface and the stress function Φ, are solved by the orthogonal point collocation method. Typical numerical results for static and dynamic buckling loads for FSDT are compared with the classical lamination theory and the dependence of the effect of the shear deformation on the thickness parameter for various boundary conditions is investigated.

  5. Preparation of Bovine Serum Albumin (BSA) nanoparticles by desolvation using a membrane contactor: a new tool for large scale production.

    Science.gov (United States)

    Yedomon, B; Fessi, H; Charcosset, C

    2013-11-01

    Albumin nanoparticles are attractive drug delivery systems as they can be prepared under soft conditions and incorporate several kinds of molecules. The aim of this study was to upscale the desolvation process for preparing Bovine Serum Albumin (BSA) nanoparticles using a membrane contactor. At a first step, the BSA nanoparticles were prepared at small scale using a syringe pump. BSA nanoparticles of 139 nm in size, with a polydispersity index of 0.046, were obtained at the optimal conditions: pH 8.2, 100 mg mL(-1) BSA albumin solution (2 mL), and 1 mL min(-1) flow rate of ethanol addition (8 mL). The upscaling with a membrane contactor was achieved by permeating ethanol through the pores of a Shirasu Porous Glass (SPG Technology Co., Japan) membrane and circulating the aqueous phase tangentially to the membrane surface. By increasing the pressure of the ethanol from 1 to 2.7 bars, a progressive decrease in nanoparticle size was obtained with a high nanoparticles yield (around 94-96%). In addition, the flow rate of the circulating phase did not affect the BSA nanoparticle characteristics. At the optimal conditions (pH 8.2, 100 mg mL(-1) BSA albumin solution, pressure of ethanol 2.7 bars, flow rate of the circulating phase 30.7 mL s(-1)), the BSA nanoparticles showed similar characteristics to those obtained with the syringe pump. Large batches of BSA nanoparticles were prepared up to 10 g BSA. The BSA nanoparticles were stable at least during 2 months at 4 °C, and their characteristics were reproducible. It was then concluded that the membrane contactor technique could be a suitable method for the preparation of albumin nanoparticles at large scale with properties similar to that obtained at small scale.

  6. Pattern dynamics in an annular CO2 laser

    OpenAIRE

    Ramon, M.L. (M. L.); R. Meucci; Allaria, E.; Boccaletti, S.

    2000-01-01

    Competition among modes in an annular CO2 laser has been experimentally and numerically analyzed. During the coexistence of di erent patterns, each of them resulting from the interaction of two transverse modes with opposite angular momentum, chaos has been experimentally detected. A numerical model, derived from the Maxwell-Bloch equations and including symmetry breaking terms, enables the interpretation of the main experimental features.

  7. Flow of viscoplastic fluids in eccentric annular geometries

    DEFF Research Database (Denmark)

    Szabo, Peter; Hassager, Ole

    1992-01-01

    A classification of flowfields for the flow of a Bingham fluid in general eccentric annular geometries is presented. Simple arguments show that a singularity can exist in the stress gradient on boundaries between zones with yielded and un-yielded fluid respectively. A Finite Element code is used...... to verify this property of the Bingham fluid. An analytical solution for the flowfield in case of small eccentricities is derived....

  8. Allopurinol induced granuloma annulare in a patient of lepromatous leprosy

    Directory of Open Access Journals (Sweden)

    Satyendra Kumar Singh

    2013-01-01

    Full Text Available Granuloma annulare (GA is a benign, inflammatory dermatosis involving dermis or subcutis with unknown etiology and poorly understood pathology. GA has characteristic histological features of necrobiosis, granuloma formation and abundant mucin deposition. Various predisposing factors, systemic diseases and drugs have been implicated in the etiology. We hereby describe a case of 70 year old male who was a known case of lepromatous leprosy, taking multidrug therapy for 6 months presented with multiple discrete, annular, firm, non tender, smooth surfaced skin colored papular lesions ranging in size from 0.5-1 cm over back for 1 month. There was past history of intake of allopurinol for hyperuricemia which was started 1 year back. There was history of similar lesions 6 months back which healed within 1 month of stopping allopurinol and he started taking the drug for the past 4 months on his own without any medical advice. Histopathological examination showed superficial and deep perivascular lymphocytic infiltrate with numerous histiocytes scattered in the intersititum of reticular dermis and abundant mucin in between the histiocytes. Allopurinol was implicated as an etiological agent and dramatic improvement was seen after stopping the drug for a period of 4 weeks. Naranjo′s algorithm showed a probable association with a score of 6. Thus the final diagnosis of allopurinol induced generalised interstitial granuolma annulare was made. Patient was advised to continue antileprotic drugs, low purine diet and avoid allopurinol intake.

  9. Guided Wave Annular Array Sensor Design for Improved Tomographic Imaging

    Science.gov (United States)

    Koduru, Jaya Prakash; Rose, Joseph L.

    2009-03-01

    Guided wave tomography for structural health monitoring is fast emerging as a reliable tool for the detection and monitoring of hotspots in a structure, for any defects arising from corrosion, crack growth etc. To date guided wave tomography has been successfully tested on aircraft wings, pipes, pipe elbows, and weld joints. Structures practically deployed are subjected to harsh environments like exposure to rain, changes in temperature and humidity. A reliable tomography system should take into account these environmental factors to avoid false alarms. The lack of mode control with piezoceramic disk sensors makes it very sensitive to traces of water leading to false alarms. In this study we explore the design of annular array sensors to provide mode control for improved structural tomography, in particular, addressing the false alarm potential of water loading. Clearly defined actuation lines in the phase velocity dispersion curve space are calculated. A dominant in-plane displacement point is found to provide a solution to the water loading problem. The improvement in the tomographic images with the annular array sensors in the presence of water traces is clearly illustrated with a series of experiments. An annular array design philosophy for other problems in NDE/SHM is also discussed.

  10. Standing wave acoustic levitation on an annular plate

    Science.gov (United States)

    Kandemir, Mehmet Hakan; Çalışkan, Mehmet

    2016-11-01

    In standing wave acoustic levitation technique, a standing wave is formed between a source and a reflector. Particles can be attracted towards pressure nodes in standing waves owing to a spring action through which particles can be suspended in air. This operation can be performed on continuous structures as well as in several numbers of axes. In this study an annular acoustic levitation arrangement is introduced. Design features of the arrangement are discussed in detail. Bending modes of the annular plate, known as the most efficient sound generation mechanism in such structures, are focused on. Several types of bending modes of the plate are simulated and evaluated by computer simulations. Waveguides are designed to amplify waves coming from sources of excitation, that are, transducers. With the right positioning of the reflector plate, standing waves are formed in the space between the annular vibrating plate and the reflector plate. Radiation forces are also predicted. It is demonstrated that small particles can be suspended in air at pressure nodes of the standing wave corresponding to a particular bending mode.

  11. A New Atom Trap The Annular Shell Atom Trap (ASAT)

    CERN Document Server

    Pilloff, H S; Pilloff, Herschel S.; Horbatsch, Marko

    2002-01-01

    In the course of exploring some aspects of atom guiding in a hollow, optical fiber, a small negative potential energy well was found just in front of the repulsive or guiding barrier. This results from the optical dipole and the van der Waals potentials. The ground state for atoms bound in this negative potential well was determined by numerically solving the Schrodinger eq. and it was found that this negative well could serve as an atom trap. This trap is referred to as the Annular Shell Atom Trap or ASAT because of the geometry of the trapped atoms which are located in the locus of points defining a very thin annular shell just in front of the guiding barrier. A unique feature of the ASAT is the compression of the atoms from the entire volume to the volume of the annular shell resulting in a very high density of atoms in this trap. This trap may have applications to very low temperatures using evaporative cooling and possibly the formation of BEC. Finally, a scheme is discussed for taking advantage of the d...

  12. Quantitative annular dark field electron microscopy using single electron signals.

    Science.gov (United States)

    Ishikawa, Ryo; Lupini, Andrew R; Findlay, Scott D; Pennycook, Stephen J

    2014-02-01

    One of the difficulties in analyzing atomic resolution electron microscope images is that the sample thickness is usually unknown or has to be fitted from parameters that are not precisely known. An accurate measure of thickness, ideally on a column-by-column basis, parameter free, and with single atom accuracy, would be of great value for many applications, such as matching to simulations. Here we propose such a quantification method for annular dark field scanning transmission electron microscopy by using the single electron intensity level of the detector. This method has the advantage that we can routinely quantify annular dark field images operating at both low and high beam currents, and under high dynamic range conditions, which is useful for the quantification of ultra-thin or light-element materials. To facilitate atom counting at the atomic scale we use the mean intensity in an annular dark field image averaged over a primitive cell, with no free parameters to be fitted. To illustrate the potential of our method, we demonstrate counting the number of Al (or N) atoms in a wurtzite-type aluminum nitride single crystal at each primitive cell over the range of 3-99 atoms.

  13. Droplet sizes, dynamics and deposition in vertical annular flow

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, J C.B.; Dukler, A E

    1985-10-01

    The role of droplets in vertical upwards annular flow is investigated, focusing on the droplet size distributions, dynamics, and deposition phenomena. An experimental program was performed based on a new laser optical technique developed in these laboratories and implemented here for annular flow. This permitted the simultaneous measurement of droplet size, axial and radial velocity. The dependence of droplet size distributions on flow conditions is analyzed. The Upper-Log Normal function proves to be a good model for the size distribution. The mechanism controlling the maximum stable drop size was found to result from the interaction of the pressure fluctuations of the turbulent flow of the gas core with the droplet. The average axial droplet velocity showed a weak dependence on gas rates. This can be explained once the droplet size distribution and droplet size-velocity relationship are analyzed simultaneously. The surprising result from the droplet conditional analysis is that larger droplet travel faster than smaller ones. This dependence cannot be explained if the drag curves used do not take into account the high levels of turbulence present in the gas core in annular flow. If these are considered, then interesting new situations of multiplicity and stability of droplet terminal velocities are encountered. Also, the observed size-velocity relationship can be explained. A droplet deposition is formulated based on the particle inertia control. This permitted the calculation of rates of drop deposition directly from the droplet size and velocities data.

  14. Studies of efficiency in a perforated rotating disc contactor using a polymer-polymer aqueous two-phase systems

    Directory of Open Access Journals (Sweden)

    L. A. Sarubbo

    2005-09-01

    Full Text Available The mass transfer process in a perforated rotating disc contactor (PRDC using a polymer-polymer aqueous two-phase system was investigated. The results show that the efficiency did not show a regular trend with the increase of the dispersed phase velocity and increased with the rotation velocity. The separation efficiency was higher for three rotating discs than for four discs. The increase in tie-line length decreased the efficiency. The separation efficiency reached high values, about 96% under conditions studied in this work.

  15. Biofilm growth of Chlorella sorokiniana in a rotating biological contactor based photobioreactor.

    Science.gov (United States)

    Blanken, W; Janssen, M; Cuaresma, M; Libor, Z; Bhaiji, T; Wijffels, R H

    2014-12-01

    Microalgae biofilms could be used as a production platform for microalgae biomass. In this study, a photobioreactor design based on a rotating biological contactor (RBC) was used as a production platform for microalgae biomass cultivated in biofilm. In the photobioreactor, referred to as Algadisk, microalgae grow in biofilm on vertical rotating disks partially submerged in a growth medium. The objective is to evaluate the potential of the Algadisk photobioreactor with respect to the effects of disk roughness, disk rotation speed and CO2 concentration. These objectives where evaluated in relationship to productivity, photosynthetic efficiency, and long-term cultivation stability in a lab-scale Algadisk system. Although the lab-scale Algadisk system is used, operation parameters evaluated are relevant for scale-up. Chlorella Sorokiniana was used as model microalgae. In the lab-scale Algadisk reactor, productivity of 20.1 ± 0.7 g per m(2) disk surface per day and a biomass yield on light of 0.9 ± 0.04 g dry weight biomass per mol photons were obtained. Different disk rotation speeds did demonstrate minimal effects on biofilm growth and on the diffusion of substrate into the biofilm. CO2 limitation, however, drastically reduced productivity to 2-4 g per m(2) disk surface per day. Productivity could be maintained over a period of 21 weeks without re-inoculation of the Algadisk. Productivity decreased under extreme conditions such as pH 9-10, temperature above 40°C, and with low CO2 concentrations. Maximal productivity, however, was promptly recovered when optimal cultivation conditions were reinstated. These results exhibit an apparent opportunity to employ the Algadisk photobioreactor at large scale for microalgae biomass production if diffusion does not limit the CO2 supply.

  16. Biosorption of heavy metals in a photo-rotating biological contactor--a batch process study.

    Science.gov (United States)

    Orandi, Sanaz; Lewis, David M

    2013-06-01

    Metal removal potential of indigenous mining microorganisms from acid mine drainage (AMD) has been well recognised in situ at mine sites. However, their removal capacity requires to be investigated for AMD treatment. In the reported study, the capacity of an indigenous AMD microbial consortium dominated with Klebsormidium sp., immobilised in a photo-rotating biological contactor (PRBC), was investigated for removing various elements from a multi-ion synthetic AMD. The synthetic AMD was composed of major (Cu, Mn, Mg, Zn, Ca, Na, Ni) and trace elements (Fe, Al, Cr, Co, Se, Ag, Mo) at initial concentrations of 2 to 100 mg/L and 0.005 to 1 mg/L, respectively. The PRBC was operated for two 7-day batch periods under pH conditions of 3 and 5. The maximum removal was observed after 3 and 6 days at pH 3 and 5, respectively. Daily water analysis data demonstrated the ability of the algal-microbial biofilm to remove an overall average of 25-40 % of the major elements at pH 3 in the order of Na > Cu > Ca > Mg > Mn > Ni > Zn, whereas a higher removal (35-50 %) was observed at pH 5 in the order of Cu > Mn > Mg > Ca > Ni > Zn > Na. The removal efficiency of the system for trace elements varied extensively between 3 and 80 % at the both pH conditions. The batch data results demonstrated the ability for indigenous AMD algal-microbial biofilm for removing a variety of elements from AMD in a PRBC. The work presents the potential for further development and scale-up to use PBRC inoculated with AMD microorganisms at mine sites for first or secondary AMD treatment.

  17. pH-sensitive micelles for targeted drug delivery prepared using a novel membrane contactor method.

    Science.gov (United States)

    Laouini, Abdallah; Koutroumanis, Konstantinos P; Charcosset, Catherine; Georgiadou, Stella; Fessi, Hatem; Holdich, Richard G; Vladisavljević, Goran T

    2013-09-25

    A novel membrane contactor method was used to produce size-controlled poly(ethylene glycol)-b-polycaprolactone (PEG-PCL) copolymer micelles composed of diblock copolymers with different average molecular weights, Mn (9200 or 10,400 Da) and hydrophilic fractions, f (0.67 or 0.59). By injecting 570 L m(-2) h(-1) of the organic phase (a 1 mg mL(-1) solution of PEG-PCL in tetrahydrofuran) through a microengineered nickel membrane with a hexagonal pore array and 200 μm pore spacing into deionized water agitated at 700 rpm, the micelle size linearly increased from 92 nm for a 5-μm pore size to 165 nm for a 40-μm pore size. The micelle size was finely tuned by the agitation rate, transmembrane flux and aqueous to organic phase ratio. An encapsulation efficiency of 89% and a drug loading of ~75% (w/w) were achieved when a hydrophobic drug (vitamin E) was entrapped within the micelles, as determined by ultracentrifugation method. The drug-loaded micelles had a mean size of 146 ± 7 nm, a polydispersity index of 0.09 ± 0.01, and a ζ potential of -19.5 ± 0.2 mV. When drug-loaded micelles where stored for 50 h, a pH sensitive drug release was achieved and a maximum amount of vitamin E (23%) was released at the pH of 1.9. When a pH-sensitive hydrazone bond was incorporated between PEG and PCL blocks, no significant change in micelle size was observed at the same micellization conditions.

  18. Ammonia removal in the carbon contactor of a hybrid membrane process.

    Science.gov (United States)

    Stoquart, Céline; Servais, Pierre; Barbeau, Benoit

    2014-12-15

    The hybrid membrane process (HMP) coupling powdered activated carbon (PAC) and low-pressure membrane filtration is emerging as a promising new option to remove dissolved contaminants from drinking water. Yet, defining optimal HMP operating conditions has not been confirmed. In this study, ammonia removal occurring in the PAC contactor of an HMP was simulated at lab-scale. Kinetics were monitored using three PAC concentrations (1-5-10 g L(-1)), three PAC ages (0-10-60 days), two temperatures (7-22 °C), in ambient influent condition (100 μg N-NH4 L(-1)) as well as with a simulated peak pollution scenario (1000 μg N-NH4L(-1)). The following conclusions were drawn: i) Using a colonized PAC in the HMP is essential to reach complete ammonia removal, ii) an older PAC offers a higher resilience to temperature decrease as well as lower operating costs; ii) PAC concentration inside the HMP reactor is not a key operating parameter as under the conditions tested, PAC colonization was not limited by the available surface; iii) ammonia flux limited biomass growth and iv) hydraulic retention time was a critical parameter. In the case of a peak pollution, the process was most probably phosphate-limited but a mixed adsorption/nitrification still allowed reaching a 50% ammonia removal. Finally, a kinetic model based on these experiments is proposed to predict ammonia removal occurring in the PAC reactor of the HMP. The model determines the relative importance of the adsorption and biological oxidation of ammonia on colonized PAC, and demonstrates the combined role of nitrification and residual adsorption capacity of colonized PAC.

  19. An electrically driven gas-liquid-liquid contactor for bioreactor and other applications

    Energy Technology Data Exchange (ETDEWEB)

    Tsouris, C.; Borole, A.P.; Kaufman, E.N.; DePaoli, D.W. [Oak Ridge National Lab., TN (United States). Chemical Technology Div.

    1999-05-01

    An electrically driven gas-liquid-liquid bioreactor is described here, in which an aqueous medium containing a biocatalyst is introduced as a discontinuous phase into an organic-continuous liquid phase containing a substrate to be converted by the biocatalyst. A gas discontinuous phase, which may be needed to provide oxygen or a gaseous substrate to the biocatalyst, is also introduced into the bioreactor. In contrast to previous work on electrically driven contactors, it was found that the electroconvection generated by the electric field between parallel-plate electrodes may be employed to increase the volume fraction of the discontinuous gas phase in the bioreactor, providing the means for enhanced mass transfer. The electrically driven bioreactor was utilized for oil desulfurization experiments with Rhodococcus sp. IGTS8 bacteria as the biocatalyst. The organic phase used in the experiments was hexadecane containing dibenzothiophene, a model sulfur compound, that is oxidatively desulfurized to 2-hydroxybiphenyl (2-HBP) by the bacteria in the presence of air or oxygen. The gas volume fraction was increased by 60% by the application of a pulsed electric field, thus providing a means for increased transport of oxygen needed for oxidative desulfurization. The velocity of droplets and bubbles was measured by a phase Doppler velocimeter. The average rising velocity of bubbles was decreased from 13 to less than 3 cm/s and the average horizontal velocity was increased from 0 to 5 cm/s as the field strength was increased from 0 to 4 kV/cm. Desulfurization rates ranged from 1.0 to 5.50 mg of 2-HBP/g of dry cells/h. The desulfurization rate with aeration was doubled under the electric field as compared to the zero-field desulfurization under the same conditions.

  20. A new model of centrifugal blood pump for cardiopulmonary bypass: design improvement, performance, and hemolysis tests.

    Science.gov (United States)

    Leme, Juliana; Fonseca, Jeison; Bock, Eduardo; da Silva, Cibele; da Silva, Bruno Utiyama; Dos Santos, Alex Eugênio; Dinkhuysen, Jarbas; Andrade, Aron; Biscegli, José F

    2011-05-01

    A new model of blood pump for cardiopulmonary bypass (CPB) application has been developed and evaluated in our laboratories. Inside the pump housing is a spiral impeller that is conically shaped and has threads on its surface. Worm gears provide an axial motion of the blood column. Rotational motion of the conical shape generates a centrifugal pumping effect and improves pumping performance. One annular magnet with six poles is inside the impeller, providing magnetic coupling to a brushless direct current motor. In order to study the pumping performance, a mock loop system was assembled. Mock loop was composed of Tygon tubes (Saint-Gobain Corporation, Courbevoie, France), oxygenator, digital flowmeter, pressure monitor, electronic driver, and adjustable clamp for flow control. Experiments were performed on six prototypes with small differences in their design. Each prototype was tested and flow and pressure data were obtained for rotational speed of 1000, 1500, 2000, 2500, and 3000 rpm. Hemolysis was studied using pumps with different internal gap sizes (1.35, 1.45, 1.55, and 1.7 mm). Hemolysis tests simulated CPB application with flow rate of 5 L/min against total pressure head of 350 mm Hg. The results from six prototypes were satisfactory, compared to the results from the literature. However, prototype #6 showed the best results. Best hemolysis results were observed with a gap of 1.45 mm, and showed a normalized index of hemolysis of 0.013 g/100 L. When combined, axial and centrifugal pumping principles produce better hydrodynamic performance without increasing hemolysis.

  1. ELECTRO-HYDRAULIC SERVO SYSTEM IN THE CENTRIFUGE FIELD

    Institute of Scientific and Technical Information of China (English)

    Dong Longlei; Yan Guirong; Li Ronglin

    2004-01-01

    The mechanical characteristics of the electro-hydraulic servo system in the centrifuge field are analyzed.The hydraulic pressure law in the centrifuge field indicates the existence of the centrifuge hydraulic pressure.The mechanical characteristics of the slide-valve and the dual nozzle flapper valve are studied,and it is found that the centrifuge field can not only increase the driving force or moment of the function units,but also decrease the stability of the components.Finally by applying Gauss minimum constraint principle,the dynamic model of the electro-hydraulic vibrator in the centrifuge field is established,and the mechanical restriction of the system is also presented.The study will be helpful for the realization of the combined vibration and centrifuge test system.

  2. Annular Pulse Shaping Technique for Large-Diameter Kolsky Bar Experiments on Concrete

    Science.gov (United States)

    2014-10-01

    lt ag e (V ) Time (microsecond) Fig. 5 Linear incident wave generated using an annular copper pulse shaper (O.D. = 25.4 mm, I.D. = 14.4 mm). Note that...AFRL-RW-EG-TP-2014-005 Annular Pulse Shaping Technique for Large- Diameter Kolsky Bar Experiments on Concrete...NUMBER (Include area code) 13-6-2014 Technical Publication October 2012 - February 2014 ANNULAR PULSE SHAPING TECHNIQUE FOR LARGE-DIAMETER KOLSKY BAR

  3. Elastic Properties of the Annular Ligament of the Human Stapes—AFM Measurement

    OpenAIRE

    Kwacz, Monika; Rymuza, Zygmunt; Michałowski, Marcin; Wysocki, Jarosław

    2015-01-01

    Elastic properties of the human stapes annular ligament were determined in the physiological range of the ligament deflection using atomic force microscopy and temporal bone specimens. The annular ligament stiffness was determined based on the experimental load-deflection curves. The elastic modulus (Young’s modulus) for a simplified geometry was calculated using the Kirchhoff–Love theory for thin plates. The results obtained in this study showed that the annular ligament is a linear elastic ...

  4. Fabrication of bulk metallic glasses by centrifugal casting method

    OpenAIRE

    R. Nowosielski; R. Babilas

    2007-01-01

    Purpose: The aim of the present work is characterization of the centrifugal casting method, apparatus andproduced amorphous materials, which are also known as bulk metallic glassesDesign/methodology/approach: The studied centrifugal casting system consists of two main parts: castingapparatus and injection system of molten alloy. The described centrifugal casting method was presented bypreparing a casting apparatus “CentriCast – 5”. The apparatus includes a cylindrical copper mold, which isrot...

  5. A curious spacetime entirely free of centrifugal acceleration

    CERN Document Server

    Dadhich, Naresh

    2012-01-01

    In the Einstein gravity, besides the usual gravitational and centrifugal potential there is an additional attractive term that couples these two together. It is fun to enquire whether the latter could fully counteract the centrifugal repulsion everywhere making the spacetime completely free of the centrifugal acceleration. We present here such a curious spacetime metric and it produces a global monopole like stresses going as $~1/r^2$ in an AdS spacetime.

  6. Design and Prototyping of Micro Centrifugal Compressor

    Institute of Scientific and Technical Information of China (English)

    Shimpei Mizuki; Gaku Minorikawa; Toshiyuki Hirano; Yuichiro Asaga; Naoki Yamaguchi; Yutaka Ohta; Eisuke Outa

    2003-01-01

    In order to establish the design methodology of ultra micro centrifugal compressor, which is the most important component of ultra micro gas turbine unit, a 10 times of the final target size model was designed, prototyped and tested. The problems to be solved for downsizing were examined and 2-dimensional impeller was chosen as the first model due to its productivity. The conventional 1D prediction method, CFD and the inverse design were attempted. The prototyped compressor was driven by using a turbocharger and the performance characteristics were measured.

  7. Rotational spectroscopy with an optical centrifuge

    CERN Document Server

    Korobenko, Aleksey; Hepburn, John W; Milner, Valery

    2013-01-01

    We demonstrate a new spectroscopic method for studying electronic transitions in molecules with extremely broad range of angular momentum. We employ an optical centrifuge to create narrow rotational wave packets in the ground electronic state of $^{16}$O$_2$. Using the technique of resonance-enhanced multi-photon ionization, we record the spectrum of multiple ro-vibrational transitions between $X^3\\Sigma_{g}^{-}$ and $C^3\\Pi_{g}$ electronic manifolds of oxygen. Direct control of rotational excitation, extending to rotational quantum numbers as high as $N\\gtrsim 120$, enables us to interpret the complex structure of rotational spectra of $C^3\\Pi_{g}$ beyond thermally accessible levels.

  8. Theory and experiments on centrifuge cratering

    Science.gov (United States)

    Schmidt, R. M.; Holsapple, K. A.

    1980-01-01

    Centrifuge experimental techniques provide possibilities for laboratory simulation of ground motion and cratering effects due to explosive loadings. The results of a similarity analysis for the thermomechanical response of a continuum show that increased gravity is a necessary condition for subscale testing when identical materials for both model and prototype are being used. The general similarity requirements for this type of subscale testing are examined both theoretically and experimentally. The similarity analysis is used to derive the necessary and sufficient requirements due to the general balance and jump equations and gives relations among all the scale factors for size, density, stress, body forces, internal energy, heat supply, heat conduction, heat of detonation, and time. Additional constraints due to specific choices of material constitutive equations are evaluated separately. The class of constitutive equations that add no further requirements is identified. For this class of materials, direct simulation of large-scale cratering events at small scale on the centrifuge is possible and independent of the actual constitutive equations. For a rate-independent soil it is shown that a small experiment at gravity g and energy E is similar to a large event at 1 G but with energy equal to g3E. Consequently, experiments at 500 G with 8 grams of explosives can be used to simulate a kiloton in the field. A series of centrifuge experiments was performed to validate the derived similarity requirements and to determine the practicality of applying the technique to dry granular soils having little or no cohesion. Ten shots using Ottawa sand at various gravities confirmed reproducibility of results in the centrifuge environment, provided information on particle size effects, and demonstrated the applicability of the derived similitude requirements. These experiments used 0.5-4 grams of pentaerythritol-tetranitrate (PETN) and 1.7 grams of lead-azide explosives. They

  9. Development of liquid nitrogen Centrifugal Pump

    Energy Technology Data Exchange (ETDEWEB)

    Abe, M; Sagiyama, R; Tsuchiya, H [Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); Takayama, T [Institute for Molecular Science, National Institutes of Natural Sciences, 38 Nishigo-Naka, Myodaiji, Okazaki, Aichi 444-8585 (Japan); Torii, Y [OMNIX, 1-15-3 Nishishinjuku, Shinjuku, Tokyo, 160-0023 (Japan); Nakamura, M [YN Nakamura Ltd, 3-9-25 Ohjima, Koto, Tokyo, 136-0072 (Japan); Hoshino, Y [JECC TORISHA Co. Ltd, 2-8-52 Yoshinodai, Kawagoe-shi, Saitama, 350-0833 (Japan); Odashima, Y [Department of Basic Sciences, University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902 (Japan)], E-mail: mirei@issp.u-tokyo.ac.jp

    2009-02-01

    Usually liquid nitrogen (LN{sub 2}) transfer from a container to a laboratory equipment takes place by applying pressure to the container to push out liquid or pouring liquid into the cryostat directly by lifting the container. In order to overcome inconvenience of pressuring or lifting containers, we have been developing the Liquid Nitrogen Centrifugal Pump of a small electric turbine pump. Significant advantages that both reducing time to fill LN{sub 2}and controlling the flow rate of liquid into the cryostat are obtained by introducing this pump. We have achieved the lift of about 800mm with the vessel's opening diameter of 28mm.

  10. Preparation of Calcium Carbonate Nanoparticles with a Continuous Gas-liquid Membrane Contactor:Particles Morphology and Membrane Fouling

    Institute of Scientific and Technical Information of China (English)

    JIA Zhiqian; CHANG Qing; QIN Jin; MAMAT Aynur

    2013-01-01

    Nanosized calcium carbonate particles were prepared with a continuous gas-liquid membrane contactor.The effects of Ca(OH)2 concentration,CO2 pressure and liquid flow velocity on the particles morphology,pressure drop and membrane fouling were studied.With rising Ca(OH)2 concentrations,the average size of the particles increased.The effects of Ca(OH)2 concentration and CO2 pressure on particles were not apparent under the experimental conditions.When the Ca(OH)2 concentration and liquid flow velocity were high,or the CO2 pressure was low,the fouling on the membrane external surface at the contactor entrance was serious due to liquid leakage,whereas the fouling was slight at exit.The fouling on the membrane inner-surface at entrance was apparent due to adsorption of raw materials.The membrane can be recovered by washing with dilute hydrochloric acid and reused for at least 6 times without performance deterioration.

  11. Experimental study on the separation of CO{sub 2} from flue gas using hollow fiber membrane contactors without wetting

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Shui-ping; Fang, Meng-Xiang; Zhang, Wei-Feng; Luo, Zhong-Yang; Cen, Ke-Fa [State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027 (China); Wang, Shu-Yuan; Xu, Zhi-Kang [Institute of Polymer Science, Zhejiang University, Hangzhou 310027 (China)

    2007-05-15

    Experiments on CO{sub 2} removal from flue gas using polypropylene (PP) hollow fiber membrane contactors were conducted in this study. Absorbents including aqueous potassium glycinate (PG) solution, aqueous solutions of monoethanolamine (MEA) and methyldiethanolamine (MDEA) were used to absorb CO{sub 2} in the experiments. Based on the wetting experimental results, aqueous PG solution can offer a higher surface tension than water, aqueous MEA and MDEA solutions. Aqueous PG solution has a lower potential of membrane wetting after a continuously steady operation for 40 h to maintain CO{sub 2} removal efficiency of about 90%. Under moderate operating conditions, effects of the temperature, flow rate, and concentration of absorbents, and the flow rate of flue gas as well as the volumetric concentration of carbon dioxide in the flue gas on the mass transfer rate of CO{sub 2} were studied on a pilot-scale test facility. Unlike conventional absorbents, the mass transfer decreases with an increasing liquid temperature when using aqueous PG solution. Results show that CO{sub 2} removal efficiency was above 90% and the mass transfer rate was above 2.0 mol/(m{sup 2} h) using the PG aqueous solution. It indicates that the hollow fiber membrane contactor has a great potential in the area of CO{sub 2} separation from flue gas when absorbent's concentration and liquid-gas pressure difference are designed elaborately. (author)

  12. Hollow fiber membrane contactors for post-combustion CO2 capture: a scale-up study from laboratory to pilot plant

    NARCIS (Netherlands)

    Chabanon, E.; Kimball, E.; Favre, E.; Lorain, O.; Goetheer, E.L.V.; Ferre, D.; Gomez, A.; Broutin, P.

    2013-01-01

    Membrane contactors have been proposed for decades as a way to achieve intensified mass transfer processes. Post-combustion CO2 capture by absorption into a chemical solvent is one of the currently most intensively investigated topics in this area. Numerous studies have already been reported, unfort

  13. Microporous hollow fibre membrane modules as gas-liquid contactors. Part 1: Physical mass transfer processes. A specific application: mass transfer in highly viscous liquids

    NARCIS (Netherlands)

    Kreulen, H.; Versteeg, G.F.; Smolders, C.A.; Swaaij, van W.P.M.

    1993-01-01

    Gas-liquid mass transfer has been studied in a membrane module with non-wetted microporous fibres in the laminar flow regime. This new type of gas/liquid contactor can be operated stabily over a large range of gas and liquid flows because gas and liquid phase do not influence each other directly. Th

  14. Separative power of an optimised concurrent gas centrifuge

    Energy Technology Data Exchange (ETDEWEB)

    Bogovalov, Sergey; Boman, Vladimir [National Research Nuclear University (MEPHI), Moscow (Russian Federation)

    2016-06-15

    The problem of separation of isotopes in a concurrent gas centrifuge is solved analytically for an arbitrary binary mixture of isotopes. The separative power of the optimised concurrent gas centrifuges for the uranium isotopes equals to δU = 12.7 (V/700 m/s)2(300 K/T)(L/1 m) kg·SWU/yr, where L and V are the length and linear velocity of the rotor of the gas centrifuge and T is the temperature. This equation agrees well with the empirically determined separative power of optimised counter-current gas centrifuges.

  15. [Design and optimization of a centrifugal pump for CPCR].

    Science.gov (United States)

    Pei, J; Tan, X; Chen, K; Li, X

    2000-06-01

    Requirements for an optimal centrifugal pump, the vital component in the equipment for cardiopulmonary cerebral resuscitation(CPCR), have been presented. The performance of the Sarns centrifugal pump (Sarns, Inc./3M, Ann arbor, MI, U.S.A) was tested. The preliminarily optimized model for CPCR was designed according to the requirements of CPCR and to the comparison and analysis of several clinically available centrifugal pumps. The preliminary tests using the centrifugal pump made in our laboratory(Type CPCR-I) have confirmed the design and the optimization.

  16. Computer simulation for centrifugal mold filling of precision titanium castings

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    Computer simulation codes were developed based on a proposed mathematical model for centrifugal mold filling processes and previous computer software for 3D mold filling and solidification of castings (CASM-3D for Windows). Sample simulations were implemented for mold filling processes of precision titanium castings under gravity and different centrifugal casting techniques. The computation results show that the alloy melt has a much stronger mold filling ability for thin section castings under a centrifugal force field than that only under the gravity. A "return back" mold filling manner is showed to be a reasonable technique for centrifugal casting processes, especially for thin section precision castings.

  17. Separative Power of an Optimised Concurrent Gas Centrifuge

    Directory of Open Access Journals (Sweden)

    Sergey Bogovalov

    2016-06-01

    Full Text Available The problem of separation of isotopes in a concurrent gas centrifuge is solved analytically for an arbitrary binary mixture of isotopes. The separative power of the optimised concurrent gas centrifuges for the uranium isotopes equals to δU = 12.7 (V/700 m/s2(300 K/T(L/1 m kg·SWU/yr, where L and V are the length and linear velocity of the rotor of the gas centrifuge and T is the temperature. This equation agrees well with the empirically determined separative power of optimised counter-current gas centrifuges.

  18. Research on the development of the centrifugal spinning

    Directory of Open Access Journals (Sweden)

    Zhang Zhiming

    2017-01-01

    Full Text Available Centrifugal spinning is a new and efficient method to produce nanofibers quickly. It makes use of the centrifugal force instead of high voltage to produce the nanofibers. The centrifugal spinning has many advantages such as no high voltage, high yield, simple structure, no pollution and can be applied to high polymer material, ceramic and metal material. In order to have more understand about this novel nanofibers formation method, this paper introduces the method of centrifugal spinning and the effect of rotation speed, the properties of material such as viscosity and solvent evaporation, collector distance which have an impact on nanofibers morphology and diameter were also analyzed.

  19. Pancreaticoduodenectomy for pancreas carcinoma occurring in the annular pancreas: report of a case.

    Science.gov (United States)

    Kawaida, Hiromichi; Kono, Hiroshi; Watanabe, Mitsuaki; Maki, Akira; Amemiya, Hidetake; Matsuda, Masanori; Fujii, Hideki; Fukasawa, Mitsuharu; Takahashi, Ei; Sano, Katsuhiro; Inoue, Tomohiro

    2015-08-01

    The annular pancreas is a rare congenital anomaly in which a ring of the pancreas parenchyma surrounds the second part of the duodenum. Malignant tumors are extremely rare in patients with an annular pancreas. A 64-year-old man presented with appetite loss and vomiting. Abdominal contrast-enhanced computed tomography (CT) indicated pancreas parenchyma surrounding the second part of the duodenum, and a hypovascular area occupying lesion in the annular pancreas. Subtotal stomach-preserving pancreaticoduodenectomy was performed. Histopathology showed pancreatic carcinoma occurring in the complete annular pancreas.

  20. Links between granuloma annulare, necrobiosis lipoidica diabeticorum and childhood diabetes: a matter of time?

    Science.gov (United States)

    Davison, James E; Davies, Alison; Moss, Celia; Kirk, Jeremy M W; Taibjee, Saleem M; Agwu, J Chizo

    2010-01-01

    Diabetes mellitus is associated with a range of dermatologic presentations, including granuloma annulare and necrobiosis lipoidica diabeticorum. Granuloma annulare occurs earlier than necrobiosis lipoidica diabeticorum and the association with diabetes mellitus is much weaker. We describe two children with diabetes who both developed granuloma annulare and later, necrobiosis lipoidica diabeticorum. We postulate that the early onset and transient nature of granuloma annulare, compared with the later onset and persistence of necrobiosis lipoidica diabeticorum, might account for the different apparent rates of association with diabetes mellitus.

  1. Electron beam diagnostic system using computed tomography and an annular sensor

    Science.gov (United States)

    Elmer, John W.; Teruya, Alan T.

    2014-07-29

    A system for analyzing an electron beam including a circular electron beam diagnostic sensor adapted to receive the electron beam, the circular electron beam diagnostic sensor having a central axis; an annular sensor structure operatively connected to the circular electron beam diagnostic sensor, wherein the sensor structure receives the electron beam; a system for sweeping the electron beam radially outward from the central axis of the circular electron beam diagnostic sensor to the annular sensor structure wherein the electron beam is intercepted by the annular sensor structure; and a device for measuring the electron beam that is intercepted by the annular sensor structure.

  2. An Annular Gap Acceleration Model for γ-ray Emission of Pulsars

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    If the binding energy of the pulsar's surface is not so high (the case of a neutron star), both negative and positive charges will flow out freely from the surface of the star. An annular free flow model for γ-ray emission of pulsars is suggested. It is emphasized that:(1) Two kinds of acceleration regions (annular and core) need to be taken into account. The annular acceleration region is defined by the magnetic field lines that cross the null charge surface within the light cylinder. (2) If the potential drop in the annular region of a pulsar is high enough (normally the case for young pulsars), charges in both the annular and the core regions could be accelerated and produce primary gamma-rays. Secondary pairs are generated in both regions and stream outwards to power the broadband radiations. (3) The potential drop grows more rapidly in the annular region than in the core region. The annular acceleration process is a key process for producing the observed wide emission beams. (4)The advantages of both the polar cap and outer gap models are retained in this model. The geometric properties of the γ-ray emission from the annular flow are analogous to that presented in a previous work by Qiao et al., which match the observations well. (5) Since charges with different signs leave the pulsar through the annular and the core regions respectively, the current closure problem can be partially solved.

  3. Virtual Prototyping Technology of AC Contactor%交流接触器虚拟样机设计技术

    Institute of Scientific and Technical Information of China (English)

    何晓燕; 许志红

    2016-01-01

    采用虚拟样机技术,建立全面反映交流接触器动态特性的三维虚拟样机模型,模型包含完整触头系统、铁心系统及连接部件,从而考虑结构特点对其运动特性的影响。引入Ansys/LS-DYNA 动力学分析软件,采用基于连续介质力学的有限元法考虑机构之间的非线性接触、碰撞问题及弹性材料的形变作用,计算接触器动作过程中的触头弹跳情况。通过三维可视化界面得到触头、铁心等运动部件位移、速度随时间变化情况,对接触器动态特性进行直观地分析。通过交流接触器虚拟样机模型的仿真,从机械动力学角度,分析触头系统闭合速度和触头弹簧初压力、金属簧片物理特性及触头表面摩擦系数对触头弹跳的影响。交流接触器的三维虚拟样机设计对其结构优化设计具有良好的理论依据和实用价值。%With virtual prototyping technology, this paper establishes the 3D virtual prototyping model of AC contactor including the whole contact system, core system and connecting parts. It reflects the real dynamic characteristics of AC contactor affected by the structure. Based on the finite method of continuum mechanics, the nonlinear contact, collision problem and elastic material deformation have been taken into account in the dynamic analysis software Ansys/LS-DYNA. Contact bounce in the process of contactor action is simulated. Moreover, by 3D visualization window, the displacement and velocity of movable contact and core changing over time are obtained and the dynamic characteristics of contactor are analyzed visually. In addition, the influence of closure speed, pre force of spring, properties of reed and friction coefficient of contact on contact bounce has been analyzed from the view of mechanical dynamics. The 3D virtual prototype design of AC contactor provides theoretical basis for its structure optimization design and has high practical value.

  4. Performance Characteristics ofAC Contactor During Voltage Sag%晃电故障下交流接触器的工作特性分析

    Institute of Scientific and Technical Information of China (English)

    林抒毅; 许志红

    2011-01-01

    电磁式交流接触器是一种应用广泛的低压电器产品,当晃电故障发生时,交流接触器可能因为不稳定电压而频繁接通或分断,对系统造成很大的影响。论文以CJ20.63A交流接触器为研究对象,建立考虑触头运动情况的电磁机构吸合过程、吸持阶段以及释放过程的磁路动态计算方程,并通过实验验证了模型的正确性。针对不同的合闸相角和工作状态进行仿真,分析了发生晃电故障时电压下降幅度、晃电故障持续时间、晃电故障发生时刻及电压相角变化对接触器工作特性的影响。结果表明,吸合阶段的晃电影响与吸合时问有直接关系,吸合以后的晃电故障影响存在临界%Electromagnetic contactor is a kind of widely used electric product. When the voltage drops suddenly, the contactor will be open or closed frequently, and the circuit will be influenced seriously. Based on the research of CJ20-63A contactor dynamic equations were established during closing, cIosed and opening processes; the movement process of the moving contact and the bounce of the contacts were considered at the meantime. The experimental data shows the model is correct. Simulations were carried out with respect to different working states and various closing phase angles. Influences of the range, duration and occurrence time of voltage drop, and the variation of voltage phases on performance characteristics of contactors were analyzed; the result indicates that the influences of voltage sag on the contactor are related to the closing time directly in the closing process; and a critical time value should be considered after the contactor is closed. This research provides the basic for the further study on the intelligent AC contactor with anti-voltage sag.

  5. Postcardiotomy centrifugal assist: a single surgeon's experience.

    Science.gov (United States)

    Curtis, Jack J; McKenney-Knox, Charlotte A; Wagner-Mann, Colette C

    2002-11-01

    Because of the infrequent application of cardiac assist devices for postcardiotomy heart failure, most published reports include the results of learning curves from multiple surgeons. Between October 1986 and June 2001, a single surgeon used 35 Sarns Centrifugal Pumps as ventricular assist devices in 21 patients with severe hemodynamic compromise after open heart surgery (0.88% incidence). Patients' ages ranged from 39 to 77 (mean, 59.6 years). Three patients required right ventricular assist devices, 4 left ventricular assist devices, and 14 had biventricular assist devices. For all, the indication for application was inability to wean from cardiopulmonary bypass despite multiple inotropes and intraaortic balloon pumping. All were expected to be intraoperative deaths without further mechanical assistance. Patients were assisted from 2 to 434 h (median, 48 h). Fifteen patients (71.4%) were weaned from device(s), and 11 patients (52.4%) were hospital survivors. Actuarial survival in those dismissed from the hospital was 78% at 5 years and 39% at 10 years. Patients facing certain demise after cardiac surgery can be salvaged with temporary centrifugal mechanical assist. Results are competitive with that achieved with more sophisticated devices. Hospital survivors enjoy reasonable longevity.

  6. Some aversive characteristics of centrifugally generated gravity.

    Science.gov (United States)

    Altman, F.

    1973-01-01

    The effective weight of rats was manipulated by centrifugation. Two effective weight levels were obtained. In three escape avoidance conditions a lever press produced a change from a base level of 2.1 g to a response level of 1.1 g. In a punishment condition a response produced a change from a 1.1 g level to a 2.1 g level and in an extinction condition responses had no effect on the 2.1 g effective weight level present. All changes took 30 sec and were maintained for an additional 10 sec before a return to base level was initiated. When responses occurred closer together than the 40 sec, they delayed the return to base level by 40 sec. This 40 sec interval is referred to as response-contingent-time. The response rate and amount of response-contingent-time served as the data. The results confirmed previous data that centrifugation is aversive. The results are interpreted as indicating that the aversiveness is attributable to the increase in effective weight, and that rats can discriminate the different angular velocity-radius of rotation combinations used.

  7. Centrifugally Stimulated Exospheric Ion Escape at Mercury

    Science.gov (United States)

    Delcourt, Dominique; Seki, K.; Terada, N.; Moore, Thomas E.

    2012-01-01

    We investigate the transport of ions in the low-altitude magnetosphere magnetosphere of Mercury. We show that, because of small spatial scales, the centrifugal effect due to curvature of the E B drift paths can lead to significant particle energization in the parallel direction. We demonstrate that because of this effect, ions with initial speed smaller than the escape speed such as those produced via thermal desorption can overcome gravity and escape into the magnetosphere. The escape route of this low-energy exosphere originating material is largely controlled by the magnetospheric convection rate. This escape route spreads over a narrower range of altitudes when the convection rate increases. Bulk transport of low-energy planetary material thus occurs within a limited region of space once moderate magnetospheric convection is established. These results suggest that, via release of material otherwise gravitationally trapped, the E B related centrifugal acceleration is an important mechanism for the net supply of plasma to the magnetosphere of Mercury.

  8. PARTICLE DISTRIBUTION IN CENTRIFUGAL ACCELERATING FIELDS

    Institute of Scientific and Technical Information of China (English)

    Yu Sirong; Zhang Xinping; He Zhenming; Liu Yaohui

    2003-01-01

    Based on continuum theory and moving law of particles, a model is presented to obtain gradient distribution of particles in centrifugal accelerating field, by which the particle distribution in gradient composite material can be predicted. The simulation shows with increases in rotating time, four regions gradually appear from the internal periphery to the external one, they are free region, transition region, steady region and surface reinforced region,and the latest three regions are defined as a rich region. Finally, the steady region disappears, and the rich region only includes transition region and surface reinforced region. The influences of centrifugal acceleration coefficient G,primary volume fraction (0,pouring temperature (p and density difference between the particle and the metal matrix on particles gradient distribution are studied in detail. The results of the theoretical analysis agree with experiment ones. Both of analysis and experiment results indicate that with the increase in G and (p, the particle distribution becomes more centralized and the consistence of particle in the surface periphery becomes larger.

  9. Geometry optimization of linear and annular plasma synthetic jet actuators

    Science.gov (United States)

    Neretti, G.; Seri, P.; Taglioli, M.; Shaw, A.; Iza, F.; Borghi, C. A.

    2017-01-01

    The electrohydrodynamic (EHD) interaction induced in atmospheric air pressure by a surface dielectric barrier discharge (DBD) actuator has been experimentally investigated. Plasma synthetic jet actuators (PSJAs) are DBD actuators able to induce an air stream perpendicular to the actuator surface. These devices can be used in the field of aerodynamics to prevent or induce flow separation, modify the laminar to turbulent transition inside the boundary layer, and stabilize or mix air flows. They can also be used to enhance indirect plasma treatment effects, increasing the reactive species delivery rate onto surfaces and liquids. This can play a major role in plasma processing and chemical kinetics modelling, where often only diffusive mechanisms are considered. This paper reports on the importance that different electrode geometries can have on the performance of different PSJAs. A series of DBD aerodynamic actuators designed to produce perpendicular jets has been fabricated on two-layer printed circuit boards (PCBs). Both linear and annular geometries were considered, testing different upper electrode distances in the linear case and different diameters in the annular one. An AC voltage supplied at a peak of 11.5 kV and a frequency of 5 kHz was used. Lower electrodes were connected to the ground and buried in epoxy resin to avoid undesired plasma generation on the lower actuator surface. Voltage and current measurements were carried out to evaluate the active power delivered to the discharges. Schlieren imaging allowed the induced jets to be visualized and gave an estimate of their evolution and geometry. Pitot tube measurements were performed to obtain the velocity profiles of the PSJAs and to estimate the mechanical power delivered to the fluid. The optimal values of the inter-electrode distance and diameter were found in order to maximize jet velocity, mechanical power or efficiency. Annular geometries were found to achieve the best performance.

  10. Axisymmetric Natural Frequencies of Statically Loaded Annular Plates

    Directory of Open Access Journals (Sweden)

    Eihab M. Abdel-Rahman

    2003-01-01

    Full Text Available We present a numerical procedure to solve the axisymmetric vibration problem of statically loaded annular plates. We use the von Kármán nonlinear plate model to account for large deformations and study the effect of static deflections on the natural frequencies and mode shapes for six combinations of boundary conditions. The shooting method is used to solve the resulting eigenvalue problem. Our results show that static deformations have a significant effect on the natural frequencies and small effect on the mode shapes of the plate. Further, the results show that the presence of in-plane stresses has a significant effect on the natural frequencies.

  11. Coexistence of disseminated granuloma annulare and asymptomatic multiple myeloma

    Directory of Open Access Journals (Sweden)

    Şebnem Aktan

    2013-09-01

    Full Text Available Granuloma annulare (GA is a benign inflammatory dermatosis of unknown cause, characterized by necrobiotic dermal papules. Several morphologic forms of GA including localized, disseminated, linear, nodular, perforating, subcutaneous, pustular and arcuate dermal erythema have been reported in the literature. Disseminated GA, a rarely seen form, has been reported in association with some hematopoietic and solid malignancies; however, it has been suggested that the exact causative relationship between malignancy and GA is unclear. We present here a 66-year-old female patient with disseminated GA associated with asymptomatic multipl myeloma.

  12. Histiocytoid Sweet's syndrome presenting with annular erythematous plaques*

    Science.gov (United States)

    Marcarini, Renata; de Araujo, Raquel Nardelli; Nóbrega, Monisa Martins; Medeiros, Karina Bittencourt; Gripp, Alexandre Carlos; Maceira, Juan Manuel Piñeiro

    2016-01-01

    Histiocytoid Sweet's Syndrome is a rare inflammatory disease described in 2005 as a variant of the classical Sweet's Syndrome (SS). Histopathologically, the dermal inflammatory infiltrate is composed mainly of mononuclear cells that have a histiocytic appearance and represent immature myeloid cells. We describe a case of Histiocytoid Sweet's Syndrome in an 18-year-old man. Although this patient had clinical manifestations compatible with SS, the cutaneous lesions consisted of erythematous annular plaques, which are not typical for this entity and have not been described in histiocytic form so far. The histiocytic subtype was confirmed by histopathological analysis that showed positivity for myeloperoxidase in multiple cells with histiocytic appearance.

  13. Final Technical Report for the MIT Annular Fuel Research Project

    Energy Technology Data Exchange (ETDEWEB)

    Mujid S. Kazimi; Pavel Hejzlar

    2008-01-31

    MIT-NFC-PR-082 (January 2006) Abstract This summary provides an overview of the results of the U.S. DOE funded NERI (Nuclear Research ENergy Initiative) program on development of the internally and externally cooled annular fuel for high power density PWRs. This new fuel was proposed by MIT to allow a substantial increase in poer density (on the order of 30% or higher) while maintaining or improving safety margins. A comprehensive study was performed by a team consisting of MIT (lead organization), Westinghuse Electric Corporation, Gamma Engineering Corporation, Framatome ANP(formerly Duke Engineering) and Atomic Energy of Canada Limited.

  14. Analysis of Cold Flowfield of Multi—Annular Opposed Jets

    Institute of Scientific and Technical Information of China (English)

    H.F.Zhao; G.C.Benelli

    1992-01-01

    The technique of the use of multi-annular opposed jets as different from using swirl and bluff body creates an excellent recirculation zone with desired size in a large space.The size of ecirculation,the magnitude of reverse velocity and turbulence intensity are much greater than those formed by bluff body.Factors affecting the flowfield include the velocity ration of the opposed jets to the primary air J.the diameter and construction of the opposed jet ring,secondary air velocity and configuration,and confined or unconfined flow condition and so on.This method is a promising way for flame stabilization in combustion technology.

  15. Comparison of superresolution effects with annular phase and amplitude filters.

    Science.gov (United States)

    Luo, Hongxin; Zhou, Changhe

    2004-12-01

    The characteristics of annular amplitude and phase filters are compared. The behavior of two-zone phase and amplitude filters as the inner zone is increased is studied in detail. Numerical simulations show that a phase filter can achieve a superresolution effect, a circular Dammann effect, and flat-topped intensity for different applications, whereas a two-zone amplitude filter can generate only a superresolution effect. The experimental results show that both amplitude and phase filters can achieve superresolution. Generally, a phase superresolution filter is recommended for its higher efficiency and its special diffraction patterns that are impossible to achieve with an amplitude filter.

  16. Unusual Presentation of Acute Annular Urticaria: A Case Report

    Directory of Open Access Journals (Sweden)

    Gilles Guerrier

    2011-01-01

    Full Text Available Acute urticarial lesions may display central clearing with ecchymotic or haemorrhagic hue, often misdiagnosed as erythema multiforme, serum-sickness-like reactions, or urticarial vasculitis. We report a case of acute annular urticaria with unusual presentation occurring in a 20-month-old child to emphasize the distinctive morphologic manifestations in a single disease. Clinicians who care for children should be able to differentiate acute urticaria from its clinical mimics. A directed history and physical examination can reliably orientate necessary diagnostic testing and allow for appropriate treatment.

  17. V5 AND V10 CONTACTOR TESTING WITH THE NEXT GENERATION (CSSX) SOLVENT FOR THE SAVANNAH RIVER SITE INTEGRATED SALT DISPOSITION PROCESS

    Energy Technology Data Exchange (ETDEWEB)

    Restivo, M.; Peters, T.; Pierce, R.; Fondeur, F.; Steeper, T.; Williams, M.; Giddings, B.; Hickman, B.; Fink, S.

    2012-01-17

    program to test the full size strip (V5) and extraction (V10) centrifugal contactors and the associated strip and extraction effluent coalescers to determine the hydraulic and mass transfer characteristics with the NGS. The test program evaluated the amount of organic carryover and the droplet size of the carryover phases using several analytical methods. Provisions were also made to enable an evaluation of coalescer performance. Stage efficiency and mass distribution ratios were determined using Cs mass transfer measurements. Using 20 millimolar (mM) extractant (instead of 50 mM), the nominal D(Cs) measured was 16.0-17.5. The data indicate that equilibrium is achieved rapidly and maintained throughout sampling. The data showed good stage efficiency for extraction (Tests 1A-1D), ranging from 98.2% for Test 1A to 90.5% for Test 1D. No statistically-significant differences were noted for operations at 12 gpm aqueous flow when compared with either 4 gpm or 8 gpm of aqueous flow. The stage efficiencies equal or exceed those previously measured using the baseline CSSX solvent system. The nominal target for scrub Cs distribution values are {approx}1.0-2.5. The first scrub test yielded an average scrub value of 1.21 and the second scrub test produced an average value of 0.78. Both values are considered acceptable. Stage efficiency was not calculated for the scrub tests. For stripping behavior, six tests were completed in a manner to represent the first strip stage. For three tests at the baseline flow ratios (O:A of 3.75:1) but at different total flow rates, the D(Cs) values were all similar at {approx}0.052. Similar behavior was observed for two tests performed at an O:A ratio of 7:1 instead of 3.75:1. The data for the baseline strip tests exhibited acceptable stage efficiency, ranging from 82.0% for low flow to 89-90% for medium and high flow. The difference in efficiency may be attributable to the low volume in the contactor housing at lower flow rates. The concentrations of

  18. V5 AND V10 CONTACTOR TESTING WITH THE NEXT GENERATION (CSSX) SOLVENT FOR THE SAVANNAH RIVER SITE INTEGRATED SALT DISPOSITION PROCESS

    Energy Technology Data Exchange (ETDEWEB)

    Restivo, M.; Peters, T.; Pierce, R.; Fondeur, F.; Steeper, T.; Williams, M.; Giddings, B.; Hickman, B.; Fink, S.

    2012-01-17

    program to test the full size strip (V5) and extraction (V10) centrifugal contactors and the associated strip and extraction effluent coalescers to determine the hydraulic and mass transfer characteristics with the NGS. The test program evaluated the amount of organic carryover and the droplet size of the carryover phases using several analytical methods. Provisions were also made to enable an evaluation of coalescer performance. Stage efficiency and mass distribution ratios were determined using Cs mass transfer measurements. Using 20 millimolar (mM) extractant (instead of 50 mM), the nominal D(Cs) measured was 16.0-17.5. The data indicate that equilibrium is achieved rapidly and maintained throughout sampling. The data showed good stage efficiency for extraction (Tests 1A-1D), ranging from 98.2% for Test 1A to 90.5% for Test 1D. No statistically-significant differences were noted for operations at 12 gpm aqueous flow when compared with either 4 gpm or 8 gpm of aqueous flow. The stage efficiencies equal or exceed those previously measured using the baseline CSSX solvent system. The nominal target for scrub Cs distribution values are {approx}1.0-2.5. The first scrub test yielded an average scrub value of 1.21 and the second scrub test produced an average value of 0.78. Both values are considered acceptable. Stage efficiency was not calculated for the scrub tests. For stripping behavior, six tests were completed in a manner to represent the first strip stage. For three tests at the baseline flow ratios (O:A of 3.75:1) but at different total flow rates, the D(Cs) values were all similar at {approx}0.052. Similar behavior was observed for two tests performed at an O:A ratio of 7:1 instead of 3.75:1. The data for the baseline strip tests exhibited acceptable stage efficiency, ranging from 82.0% for low flow to 89-90% for medium and high flow. The difference in efficiency may be attributable to the low volume in the contactor housing at lower flow rates. The concentrations of

  19. High Efficiency Centrifugal Compressor for Rotorcraft Applications

    Science.gov (United States)

    Medic, Gorazd; Sharma, Om P.; Jongwook, Joo; Hardin, Larry W.; McCormick, Duane C.; Cousins, William T.; Lurie, Elizabeth A.; Shabbir, Aamir; Holley, Brian M.; Van Slooten, Paul R.

    2014-01-01

    The report "High Efficiency Centrifugal Compressor for Rotorcraft Applications" documents the work conducted at UTRC under the NRA Contract NNC08CB03C, with cost share 2/3 NASA, and 1/3 UTRC, that has been extended to 4.5 years. The purpose of this effort was to identify key technical barriers to advancing the state-of-the-art of small centrifugal compressor stages; to delineate the measurements required to provide insight into the flow physics of the technical barriers; to design, fabricate, install, and test a state-of-the-art research compressor that is representative of the rear stage of an axial-centrifugal aero-engine; and to acquire detailed aerodynamic performance and research quality data to clarify flow physics and to establish detailed data sets for future application. The design activity centered on meeting the goal set outlined in the NASA solicitation-the design target was to increase efficiency at higher work factor, while also reducing the maximum diameter of the stage. To fit within the existing Small Engine Components Test Facility at NASA Glenn Research Center (GRC) and to facilitate component re-use, certain key design parameters were fixed by UTRC, including impeller tip diameter, impeller rotational speed, and impeller inlet hub and shroud radii. This report describes the design effort of the High Efficiency Centrifugal Compressor stage (HECC) and delineation of measurements, fabrication of the compressor, and the initial tests that were performed. A new High-Efficiency Centrifugal Compressor stage with a very challenging reduction in radius ratio was successfully designed, fabricated and installed at GRC. The testing was successful, with no mechanical problems and the running clearances were achieved without impeller rubs. Overall, measured pressure ratio of 4.68, work factor of 0.81, and at design exit corrected flow rate of 3 lbm/s met the target requirements. Polytropic efficiency of 85.5 percent and stall margin of 7.5 percent were

  20. Separative power of an optimised concurrent gas centrifuge

    CERN Document Server

    Bogovalov, S V

    2015-01-01

    The problem of separation of uranium isotopes in a concurrent gas centrifuge is solved analytically. Separative power of the optimized concurrent gas centrifuges equals to $\\delta U=12.7(V/700~{\\rm m/s})^2 (300 ~{\\rm K}/T)L, ~{\\rm kg ~SWU/yr}$, where $L$ and $V$ are the length and linear velocity of the rotor of the gas centrifuge, $T$ is the temperature. This formula well agrees with an empirical separative power of counter current gas centrifuges. The optimal value of the separative power is not unique on the plane $(p_w,v_z)$, where $p_w$ is pressure at the wall of the rotor and $v_z$ is axial velocity of the gas. This value is constant on a line defined by the equation $p_wv_z=constant$. Equations defining the mass flux and the electric power necessary to support the rotation of the gas centrifuge are obtained.

  1. Portal annular pancreas: a systematic review of a clinical challenge.

    Science.gov (United States)

    Harnoss, Jonathan M; Harnoss, Julian C; Diener, Markus K; Contin, Pietro; Ulrich, Alexis B; Büchler, Markus W; Schmitz-Winnenthal, Friedrich H

    2014-10-01

    Portal annular pancreas (PAP) is an asymptomatic congenital pancreas anomaly, in which portal and/or mesenteric veins are encased by pancreas tissue. The aim of the study was to determine the role of PAP in pancreatic surgery as well as its management and potential complication, specifically, postoperative pancreatic fistula (POPF).On the basis of a case report, the MEDLINE and ISI Web of Science databases were systematically reviewed up to September 2012. All articles describing a case of PAP were considered.In summary, 21 studies with 59 cases were included. The overall prevalence of PAP was 2.4% and the patients' mean (SD) age was 55.9 (16.2) years. The POPF rate in patients with PAP (12 pancreaticoduodenectomies and 3 distal pancreatectomies) was 46.7% (in accordance with the definition of the International Study Group of Pancreatic Surgery).Portal annular pancreas is a quite unattended pancreatic variant with high prevalence and therefore still remains a clinical challenge to avoid postoperative complications. To decrease the risk for POPF, attentive preoperative diagnostics should also focus on PAP. In pancreaticoduodenectomy, a shift of the resection plane to the pancreas tail should be considered; in extensive pancreatectomy, coverage of the pancreatic remnant by the falciform ligament could be a treatment option.

  2. Non-null annular subaperture stitching interferometry for aspheric test

    Science.gov (United States)

    Zhang, Lei; Liu, Dong; Shi, Tu; Yang, Yongying; Chong, Shiyao; Miao, Liang; Huang, Wei; Shen, Yibing; Bai, Jian

    2015-10-01

    A non-null annular subaperture stitching interferometry (NASSI), combining the subaperture stitching idea and non-null test method, is proposed for steep aspheric testing. Compared with standard annular subaperture stitching interferometry (ASSI), a partial null lens (PNL) is employed as an alternative to the transmission sphere, to generate different aspherical wavefronts as the references. The coverage subaperture number would thus be reduced greatly for the better performance of aspherical wavefronts in matching the local slope of aspheric surfaces. Instead of various mathematical stitching algorithms, a simultaneous reverse optimizing reconstruction (SROR) method based on system modeling and ray tracing is proposed for full aperture figure error reconstruction. All the subaperture measurements are simulated simultaneously with a multi-configuration model in a ray-tracing program, including the interferometric system modeling and subaperture misalignments modeling. With the multi-configuration model, full aperture figure error would be extracted in form of Zernike polynomials from subapertures wavefront data by the SROR method. This method concurrently accomplishes subaperture retrace error and misalignment correction, requiring neither complex mathematical algorithms nor subaperture overlaps. A numerical simulation exhibits the comparison of the performance of the NASSI and standard ASSI, which demonstrates the high accuracy of the NASSI in testing steep aspheric. Experimental results of NASSI are shown to be in good agreement with that of Zygo® VerifireTM Asphere interferometer.

  3. A compact annular ring microstrip antenna for WSN applications.

    Science.gov (United States)

    Wang, Daihua; Song, Linli; Zhou, Hanchang; Zhang, Zhijie

    2012-01-01

    A compact annular ring microstrip antenna was proposed for a wireless sensor network (WSN) application in the 2.4 GHz band. In this paper the major considerations of the conformal antenna design were the compact size and the impact on antenna's performance of a steel installation base. By using a chip resistor of large resistance (120 Ω) the antenna size was reduced to 38% of that a conventional annular ring patch antenna. With the addition of the steel installation base the resonant frequency of the antenna increases about 4.2% and the bandwidth reduces from 17.5% to 11.7% by adjusting the load resistance simultaneously. Several key parameters were discussed and optimized, and the antenna was fabricated and its performance measured. The antenna is well matched at 2.4 GHz with 34.2 dB return loss and -2.5 dBi peak gain. Meanwhile, it exhibits excellent radiation patterns with very low cross-polarization levels.

  4. A Compact Annular Ring Microstrip Antenna for WSN Applications

    Directory of Open Access Journals (Sweden)

    Daihua Wang

    2012-06-01

    Full Text Available A compact annular ring microstrip antenna was proposed for a wireless sensor network (WSN application in the 2.4 GHz band. In this paper the major considerations of the conformal antenna design were the compact size and the impact on antenna’s performance of a steel installation base. By using a chip resistor of large resistance (120 Ω the antenna size was reduced to 38% of that a conventional annular ring patch antenna. With the addition of the steel installation base the resonant frequency of the antenna increases about 4.2% and the bandwidth reduces from 17.5% to 11.7% by adjusting the load resistance simultaneously. Several key parameters were discussed and optimized, and the antenna was fabricated and its performance measured. The antenna is well matched at 2.4 GHz with 34.2 dB return loss and –2.5 dBi peak gain. Meanwhile, it exhibits excellent radiation patterns with very low cross-polarization levels.

  5. Characterization of interfacial waves in horizontal core-annular flow

    Science.gov (United States)

    Tripathi, Sumit; Bhattacharya, Amitabh; Singh, Ramesh; Tabor, Rico F.

    2016-11-01

    In this work, we characterize interfacial waves in horizontal core annular flow (CAF) of fuel-oil and water. Experimental studies on CAF were performed in an acrylic pipe of 15.5mm internal diameter, and the time evolution of the oil-water interface shape was recorded with a high speed camera for a range of different flow-rates of oil (Qo) and water (Qw). The power spectrum of the interface shape shows a range of notable features. First, there is negligible energy in wavenumbers larger than 2 π / a , where a is the thickness of the annulus. Second, for high Qo /Qw , there is no single dominant wavelength, as the flow in the confined annulus does not allow formation of a preferred mode. Third, for lower Qo /Qw , a dominant mode arises at a wavenumber of 2 π / a . We also observe that the power spectrum of the interface shape depends weakly on Qw, and strongly on Qo, perhaps because the net shear rate in the annulus appears to depend weakly on Qw as well. We also attempt to build a general empirical model for CAF by relating the interfacial stress (calculated via the mean pressure gradient) to the flow rate in the annulus, the annular thickness and the core velocity. Authors are thankful to Orica Mining Services (Australia) for the financial support.

  6. Annular bullous lesions with atypical erythema multiforme in leprosy.

    Science.gov (United States)

    Shah, Aishani; Mahajan, Rashmi; Ninama, Kishan; Bilimoria, Freny

    2014-09-01

    Erythema nodosum leprosum (ENL) is an immune complex-mediated reaction that may complicate the course of multibacillary leprosy. Bullous lesions in Type II reaction, though reported, are exceedingly rare. We report the case of a 32 year old female patient who presented initially at our OPD with erythema nodosum. Cutaneous examination revealed impaired sensation over dorsum of right foot and thickened right lateral popliteal nerve. Slit skin smear (SSS) from ear lobes revealed AFB with a bacteriological index of 2+. She was started on MDT, tablet ofloxacin 200 mg twice a day, and 30 mg oral prednisolone. Two months later, she presented with generalised pruritus, large target lesions over the back, and hemorrhagic bullae over lower extremities and annular pattern of bullae, over both arms. A SSS was repeated which was positive for AFB. Histopathology from bullous lesions was consistent with ENL. Direct Immunofluorescence (DIF) study was negative. Our patient improved rapidly after she was started on thalidomide 100 mg twice daily, with withdrawal of ofloxacin. Erythema Multiforme (EMF) and annular bullous lesions have been reported in patients on treatment with ofloxacin. This case is being presented due to the unusual and varied manifestation of Type II lepra reaction in a 34 year old female patient.

  7. Droplet entrainment rate in gas-liquid annular flow

    Energy Technology Data Exchange (ETDEWEB)

    Sawant, P. [Energy Research Inc., Rockville, Maryland (United States); Liu, Y.; Ishii, M. [Purdue Univ., West Lafayette, Indiana (United States); Mori, M. [Tokyo Electric Power Co., Inc., Yokohama (Japan); Chen, S. [Purdue Univ., West Lafayette, Indiana (United States)

    2011-07-01

    Droplet entrainment and deposition are the two most important physical phenomena in the gas-liquid annular two-phase flow. Modeling of these phenomena is essential for the estimation of dryout margins in the Light Water Reactors (LWRs) and the boilers. In this study, gas-liquid annular two-phase flow experiments are performed in a vertical round tube test section under adiabatic conditions. Air-water and organic fluid Freon-113 are used as the test fluids. The experiments covered a wide range of pressure and flow conditions. Liquid film extraction technique was used for the measurement of droplet entrainment and deposition rates. Additionally, the thickness of liquid film was measured in the air-water experiments using the ring type conductance probes. In this paper, the experimental data on entrainment rate is used to analyze the currently available correlations in the literature. The analysis showed that the existing correlations failed to predict the data at high gas velocity conditions. At high gas velocity, the experimental entrainment rate approaches a maximum limiting value; however, the correlations predicted continuously increasing entrainment rate as the gas velocity increases. (author)

  8. Electroactive liquid lens driven by an annular membrane.

    Science.gov (United States)

    Wei, Kang; Domicone, Nicholas Wade; Zhao, Yi

    2014-03-01

    Unlike traditional focalization that recruits multiple moving lens elements to adjust focus, liquid lenses deliver adaptive focusing by simply tuning the surface profile of liquid or the elastomer that encloses liquid. Its simple and compact configuration, low cost, and actuation efficiency promise wide industrial, medical, and consumer applications. Dielectric elastomers (DEs), one type of commercially available soft active material, have been a good fit for creating adaptive optics. In this Letter, we present an adaptive, membrane-sealed liquid lens hydrostatically coupled to a concentric annular DE actuator. Electric actuation deforms the annular DE, which induces fluid transmission between the lens part and the actuation part for lens actuation. The maximum measured focal range was from 25.4 to 105.2 mm within 1.0 kV, which significantly outperforms the existing DE-actuated liquid lenses and eliminates the need for prestraining. The lens also enables varied focal ranges by simply adjusting its initial surface sagitta, providing flexibility for practical imaging applications.

  9. Maximizing prosthetic valve size with the Top Hat supra-annular aortic valve

    DEFF Research Database (Denmark)

    Aagaard, Jan; Geha, Alexander S.

    2007-01-01

    BACKGROUND AND AIM OF THE STUDY: The CarboMedics Top Hat supra-annular aortic valve allows a one-size (and often two-size) increase over the standard intra-annular valve. This advantage should minimize the risk of patient-prosthesis mismatch, where the effective prosthetic valve orifice area...

  10. Simultaneous occurrence of ulcerated necrobiosis lipoidica and granuloma annulare in a patient: case report.

    Science.gov (United States)

    Souza, Fernanda Homem de Mello de; Ribeiro, Camila Ferrari; Pereira, Marcela Abou Chami; Mesquita, Lismary; Fabrício, Lincoln

    2011-01-01

    Simultaneous occurrence of granuloma annulare and necrobiosis lipoidica is quite rare. There are seven reported cases in the literature, but only one presenting ulcerated necrobiosis lipoidica. We report a 39-year-old male with histopathologically confirmed granuloma annulare and ulcerated necrobiosis lipoidica, without diabetes mellitus.

  11. Design and characterization of the annular cathode high current pulsed electron beam source for circular components

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Wei; Wang, Langping, E-mail: aplpwang@hit.edu.cn; Wang, Xiaofeng

    2016-08-01

    Highlights: • An annular cathode for HCPEB irradiation of circular components was designed. • The processing window for the annular cathode is obtained. • Irradiation thickness uniformity along the circumferential direction exceeds 90%. - Abstract: In order to irradiate circular components with high current pulsed electron beam (HCPEB), an annular cathode based on carbon fiber bunches was designed and fabricated. Using an acceleration voltage of 25 kV, the maximum pulsed irradiation current and energy of this annular cathode can reach 7.9 kA and 300 J, respectively. The irradiation current density distribution of the annular cathode HCPEB source measured along the circumferential direction shows that the annular cathode has good emission uniformity. In addition, four 9310 steel substrates fixed uniformly along the circumferential direction of a metal ring substrate were irradiated by this annular cathode HCPEB source. The surface and cross-section morphologies of the irradiated samples were characterized by scanning electron microscopy (SEM). SEM images of the surface reveal that crater and surface undulation have been formed, which hints that the irradiation energy of the HCPEB process is large enough for surface modification of 9310 steel. Meanwhile, SEM cross-section images exhibit that remelted layers with a thickness of about 5.4 μm have been obtained in all samples, which proves that a good practical irradiation uniformity can be achieved by this annular cathode HCPEB source.

  12. Erythema annulare centrifugum as presenting sign of activation of breast cancer*

    Science.gov (United States)

    Topal, Ilteris Oguz; Topal, Yunus; Sargan, Aytul; Duman, Hatice; Gungor, Sule; Goncu, Ozgur Emek Kocaturk; Ozekinci, Selver

    2015-01-01

    Erythema annulare centrifugum is a figurate erythema of unknown etiology. It has been associated with many different entities, including infections, food allergy, drug reactions and malignant neoplasms. Herein, we report a case of erythema annulare centrifugum as presenting sign of activation of breastcancer. PMID:26734884

  13. Erythema annulare centrifugum as presenting sign of activation of breast cancer.

    Science.gov (United States)

    Topal, Ilteris Oguz; Topal, Yunus; Sargan, Aytul; Duman, Hatice; Gungor, Sule; Goncu, Ozgur Emek Kocaturk; Ozekinci, Selver

    2015-01-01

    Erythema annulare centrifugum is a figurate erythema of unknown etiology. It has been associated with many different entities, including infections, food allergy, drug reactions and malignant neoplasms. Herein, we report a case of erythema annulare centrifugum as presenting sign of activation of breastcancer.

  14. Annular Lichenoid Dermatitis of Youth: A Chronic Case Managed Using Pimecrolimus.

    Science.gov (United States)

    Malachowski, Stephen J; Creasey, Mackenzie; Kinkley, Nancy; Heaphy, Michael R

    2016-11-01

    Annular lichenoid dermatitis of youth, first described in 2003, is a rare and occasionally chronic skin disease. We report a case of annular lichenoid dermatitis of youth relapsing over the course of 5 years successfully treated and maintained with topical pimecrolimus cream.

  15. Core-annular flow through a horizontal pipe: Hydrodynamic counterbalancing of buoyancy force on core

    NARCIS (Netherlands)

    Ooms, G.; Vuik, C.; Poesio, P.

    2007-01-01

    A theoretical investigation has been made of core-annular flow: the flow of a high-viscosity liquid core surrounded by a low-viscosity liquid annular layer through a horizontal pipe. Special attention is paid to the question of how the buoyancy force on the core, caused by a density difference betwe

  16. [Hemodynamic analysis of a centrifugal blood pump].

    Science.gov (United States)

    Wang, Yang; Yang, Ming; Xu, Zihao; Zhuang, Xiaoqi; Li, Qilei; Xu, Liang

    2015-01-01

    This paper built the mathematical model of a centrifugal blood pump, which was designed by ourselves, combined it with that of the human cardiovascular system and simulated the coupling system using Matlab. Then we set up the experiment platform, linked the blood pump to mock human cardiovascular system in case of three-stage heart failure, and measured aortic pressure and flow under different speed. The comparison between experiment results and simulation results not only indicates the coupling model is correct and the blood pump works well, but also shows that with the increase of blood pump speed, the pulsation of aortic pressure and flow will be reduced, this situation will affect the structure and function of blood vessels.

  17. Centrifugal acceleration of plasma in pulsar magnetosphere

    Indian Academy of Sciences (India)

    R T Gangadhara; V Krishna

    2003-12-01

    We present a relativistic model for the centrifugal acceleration of plasma bunches and the coherent radio emission in pulsar magnetosphere. We find that rotation broadens the width of leading component compared to the width of trailing component. We explain this difference in the component widths using the nested cone emission geometry. We estimate the effect of pulsar spin on the Stokes parameters, and find that the inclination between the rotation and magnetic axes can introduce an asymmetry in the circular polarization of the conal components. We analyse the single pulse polarization data of PSR B0329+54 at 606 MHz, and find that in its conal components, one sense of circular polarization dominates in the leading component while the other sense dominates in the trailing component. Our simulation shows that changing the sign of the impact parameter changes the sense of circular polarization as well as the swing of polarization angle.

  18. Numerical simulation of centrifugal casting of pipes

    Science.gov (United States)

    Kaschnitz, E.

    2012-07-01

    A numerical simulation model for the horizontal centrifugal pipe casting process was developed with the commercial simulation package Flow3D. It considers - additionally to mass, energy and momentum conservation equations and free surface tracking - the fast radial and slower horizontal movement of the mold. The iron inflow is not steady state but time dependent. Of special importance is the friction between the liquid and the mold in connection with the viscosity and turbulence of the iron. Experiments with the mold at controlled revolution speeds were carried out using a high-speed camera. From these experiments friction coefficients for the description of the interaction between mold and melt were obtained. With the simulation model, the influence of typical process parameters (e.g. melts inflow, mold movement, melt temperature, cooling media) on the wall thickness of the pipes can be studied. The comparison to results of pipes from production shows a good agreement between simulation and reality.

  19. Annular core liquid-salt cooled reactor with multiple fuel and blanket zones

    Science.gov (United States)

    Peterson, Per F.

    2013-05-14

    A liquid fluoride salt cooled, high temperature reactor having a reactor vessel with a pebble-bed reactor core. The reactor core comprises a pebble injection inlet located at a bottom end of the reactor core and a pebble defueling outlet located at a top end of the reactor core, an inner reflector, outer reflector, and an annular pebble-bed region disposed in between the inner reflector and outer reflector. The annular pebble-bed region comprises an annular channel configured for receiving pebble fuel at the pebble injection inlet, the pebble fuel comprising a combination of seed and blanket pebbles having a density lower than the coolant such that the pebbles have positive buoyancy and migrate upward in said annular pebble-bed region toward the defueling outlet. The annular pebble-bed region comprises alternating radial layers of seed pebbles and blanket pebbles.

  20. CENTRIFUGAL PUMP AND SHAFT SEALING MEANS

    Science.gov (United States)

    Rushing, F.C.

    1960-09-01

    A description is given of sealing means between a hollow rotatable shaft and a stationary member surrounding the shaft which defines therewith a sealing space of annular cross-section, comprising a plurality of axially spaced rings held against seats by ring springs which serve to subdivide the sealing space- into a plurality of zones. Process gas introduced into the hollow shaft through a port communicating with a centrally located zone which iu turn communicates with a bore in the sleeve, is removed from the shaft through a second port communicating with an adjacent central zone and discharged through a second bore. A sealant gas is supplied to an end zone under a pressure sufficient to cause it to flow axially into adjacent zones and then maintained at a lower pressure than either the sealant gas source or the process gas inlet zone, preventing the sealant gas from entering the shaft and allowing gases leaking into the sealant gas to be withdrawn and led to a separator.

  1. A straight path centrifugal blood pump concept in the Capiox centrifugal pump.

    Science.gov (United States)

    Kijima, T; Oshiyama, H; Horiuchi, K; Nogawa, A; Hamasaki, H; Amano, N; Nojiri, C; Fukasawa, H; Akutsu, T

    1993-07-01

    This article describes comparative studies of a newly developed "straight path" centrifugal pump (Capiox centrifugal pump) targeted for open-heart surgery and circulatory support. A unique straight path design of the rotor was very effective in reducing the pump's rotational speed and prime volume. This pump was evaluated for hydraulics, hemolysis, depriming characteristics, cavitation, and heat generation. Two commercially available centrifugal pumps, the Biomedicus cone-type pump and the Sarns 3M impeller-type pump, were used as controls. The new pump required the lowest pump speed to produce the same flow rates under the same pressure loads and demonstrated the lowest hemolysis and the lowest temperature rise with the outlet clamped. The air volume required to deprime the new pump was one-third to one-half that for the other pumps, and no sign of cavitation was observed even if a small amount of air was introduced to the pump inlet under a negative pressure of 200 mm Hg.

  2. A Novel Fabrication Method for Functionally Graded Materials under Centrifugal Force: The Centrifugal Mixed-Powder Method

    Directory of Open Access Journals (Sweden)

    Eri Miura-Fujiwara

    2009-12-01

    Full Text Available One of the fabrication methods for functionally graded materials (FGMs is a centrifugal solid-particle method, which is an application of the centrifugal casting technique. However, it is the difficult to fabricate FGMs containing nano-particles by the centrifugal solid-particle method. Recently, we proposed a novel fabrication method, which we have named the centrifugal mixed-powder method, by which we can obtain FGMs containing nano-particles. Using this processing method, Cu-based FGMs containing SiC particles and Al-based FGMs containing TiO2 nano-particles on their surfaces have been fabricated. In this article, the microstructure and mechanical property of Cu/SiC and Al/TiO2 FGMs, fabricated by the centrifugal mixed-powder method are reviewed.

  3. Control of nitratation in an oxygen-limited autotrophic nitrification/denitrification rotating biological contactor through disc immersion level variation.

    Science.gov (United States)

    Courtens, Emilie N P; Boon, Nico; De Clippeleir, Haydée; Berckmoes, Karla; Mosquera, Mariela; Seuntjens, Dries; Vlaeminck, Siegfried E

    2014-03-01

    With oxygen supply playing a crucial role in an oxygen-limited autotrophic nitrification/denitrification (OLAND) rotating biological contactor (RBC), its controlling factors were investigated in this study. Disc rotation speeds (1.8 and 3.6rpm) showed no influence on the process performance of a lab-scale RBC, although abiotic experiments showed a significant effect on the oxygenation capacity. Estimations of the biological oxygen uptake rate revealed that 85-89% of the oxygen was absorbed by the microorganisms during the air exposure of the discs. Indeed, increasing the disc immersion (50 to 75-80%) could significantly suppress undesired nitratation, on the short and long term. The presented results demonstrated that nitratation could be controlled by the immersion level and revealed that oxygen control in an OLAND RBC should be predominantly based on the atmospheric exposure percentage of the discs.

  4. Preparation of vitamin E loaded nanocapsules by the nanoprecipitation method: from laboratory scale to large scale using a membrane contactor.

    Science.gov (United States)

    Khayata, N; Abdelwahed, W; Chehna, M F; Charcosset, C; Fessi, H

    2012-02-28

    Vitamin E or α-tocopherol is widely used as a strong antioxidant in many medical and cosmetic applications, but is rapidly degraded, because of its light, heat and oxygen sensitivity. In this study, we applied the nanoprecipitation method to prepare vitamin E-loaded nanocapsules, at laboratory-scale and pilot-scale. We scaled-up the preparation of nanocapsule with the membrane contactor technique. The effect of several formulation variables on the vitamin E-loaded nanocapsules properties (mean diameter, zeta potential, and drug entrapment efficiency) was investigated. The optimized formulation at laboratory-scale and pilot-scale lead to the preparation of vitamin E-loaded nanocapsules with mean diameter of 165 and 172 nm, respectively, and a high encapsulation efficiency (98% and 97%, respectively).

  5. Hydrodynamic and absorption studies of carbon dioxide absorption in aqueous amide solutions using a bubble column contactor

    Directory of Open Access Journals (Sweden)

    A. Blanco

    2013-12-01

    Full Text Available The present work analyses the carbon dioxide absorption process in aqueous n-alkylpyrrolidones solutions, from the point of view of hydrodynamic studies as well as mass transfer, using a bubble column contactor. An analysis of the influence of solute concentration and gas flow-rate is complemented by the study of the effect caused by the alkyl group on the hydrodynamics and mass transfer. The presence of this kind of substance produces a decrease in mass transfer rate, but on the basis of interfacial area and mass transfer coefficient values, ethyl-2-pyrrolidine (EP shows suitable characteristics to replace methyl-2-pyrrolidine (MP in gas separation processes due to its lower safety problems.

  6. Operating Characteristics Test System for AC/DC Contactor%交直流接触器动作特性测试系统

    Institute of Scientific and Technical Information of China (English)

    林文贵; 许志红

    2014-01-01

    The operating characteristics test system of AC/DC contactor was introduced.It achieves phase selection in the closing and opening course of contactor.Keyence laser displacement sensor is used to achieve the test of displacement of contact and iron core changing over time.Moreover,the sound signal making in the closing course of contactor by electret microphone is captured.The voltage,current of coil and main circuit with three-phase contacts are obtained.All signals mentioned above transmitting to PC based on data-acquisition,the system achieves data processing,automatically measuring and saving.The test system provides technical support for contactor studying and simulation,control strategy verifying of AC/DC contactor.It is of theoretical and practical significance in the design and development of AC/DC contactor.%介绍了一套交/直流接触器动作特性测试系统。系统实现了对交流接触器的选相分/合闸控制,采用激光位移传感器实现触头与铁心动态位移测试,驻极体传声器采集接触器闭合过程声音信号,霍尔传感器采集线圈回路和三相触头回路电压电流信号;同时使用数据采集卡将信号采集到上位机,完成数据的处理分析、自动测量、数据存储等功能。系统为交直流接触器的仿真研究、控制方案等提供技术支持,对提高接触器的设计与开发水平具有理论和实际意义。

  7. Continuous measuring method for static magnetic force of contactors%一种接触器静态吸力连续测量的方法

    Institute of Scientific and Technical Information of China (English)

    黄文锋; 朱翔鸥

    2012-01-01

    The dynamic process of AC contactor involves the coupling of electromagnetic conversion and mechanical movement, while the magnitude of the electromagnetic force is the function of both exciting current and the moving core displacement. However,there are some limitations in numerical calculation and simulation method. The results can not reflect the real process of the dynamics of the contactors. In order to understand the dynamic response of AC contactor precisely.it isimpossible to measure the electromagnetic force based on different currents and displacements. A method to achieve continuous measurement of the static magnetic force of contactors using force sensor is proposed, which can measure the electromagnetic force based on different currents and displacements. This method is used to measure the electromagnetic force of CJ20-100 contactor. The results are compared to simulation result, which shows that the methods is accurate. The measurement method provides an important reference value to study the dynamic characteristics of the electromagnetic contactors.%交流接触器动态过程涉及电磁转换和机械运动的耦合,其电磁吸力的大小同时是励磁电流和动铁芯位移的函数.目前广泛采用的数值计算与模拟仿真方法存在一定的局限性,其计算仿真结果难以反映真实的运动过程.为了准确掌握交流接触器的动态响应过程,需要对不同电流、不同位移时的电磁吸力进行测量.开发一种基于拉力传感器静态电磁吸力测量的方法,可以对不同电流或者不同位移时的电磁吸力进行连续测量.采用该测量方法对CJ20-100型接触器进行了实验研究,将测量结果与模拟仿真结果相比较,验证了该测量方法的准确性.该测量方法为电磁机构动态特性测量方法的研究提供了重要的参考价值.

  8. Technology of Zero-Current Breaking of Intelligent AC Contactor%智能交流接触器零电流分断技术

    Institute of Scientific and Technical Information of China (English)

    鲍光海; 张培铭

    2012-01-01

    Zero-current breaking technology is an important content in the research of intelligent AC contactor, In this paper, the optimization calculation aimed to breaking quickly of the electromagnetic mechanism of the intelligent AC contactor is conducted, by using the ANSYS electromagnetic software and the artificial fish swarm optimization algorithm based on genetic algorithm. This method not only ensures the reliable contact process of the intelligent AC contactor, but also realizes a quick release of the executive mechanism, thus greatly reduces the influence to the stability and accuracy of the three-phase contactors, especially the first opening phase when zero-current breaking, which improves the reliability of zero-current breaking and increases the technology research level of the intelligent AC contactor. A prototype is made based on the results of the optimization designation. The testing results show that the breaking time of the intelligent AC contactor is shortened greatly, and the stability of the breaking time is improved significantly too, so the reliability of the zero-current breaking increases significantly.%零电流分断技术是交流接触器智能化研究的重要内容。本文采用Ansys电磁场软件和基于遗传算法的人工鱼群优化算法对智能交流接触器电磁动作机构进行以快速分断为目标的优化计算,不仅保证智能交流接触器可靠与优化的接通过程,而且实现了动作机构快速释放,从而大幅度减小机构分散性对三相触头特别是首开相触头零电流分断准确性与稳定性影响,提高零电流分断的可靠性,从而提高了交流接触器智能化技术的研究水平。根据优化设计结果加工了样机,对样机测试与试验的结果表明,智能交流接触器的分断时间大幅缩短,三相触头分断时间稳定性也得到明显改善,因此零电流分断的可靠性显著提高。

  9. International Space Station (ISS) Plasma Contactor Unit (PCU) Utilization Plan Assessment Update

    Science.gov (United States)

    Hernandez-Pellerano, Amri; Iannello, Christopher J.; Garrett, Henry B.; Ging, Andrew T.; Katz, Ira; Keith, R. Lloyd; Minow, Joseph I.; Willis, Emily M.; Schneider, Todd A.; Whittlesey, Edward J.; Wollack, Edward J.; Wright, Kenneth H.

    2014-01-01

    The International Space Station (ISS) vehicle undergoes spacecraft charging as it interacts with Earth's ionosphere and magnetic field. The interaction can result in a large potential difference developing between the ISS metal chassis and the local ionosphere plasma environment. If an astronaut conducting extravehicular activities (EVA) is exposed to the potential difference, then a possible electrical shock hazard arises. The control of this hazard was addressed by a number of documents within the ISS Program (ISSP) including Catastrophic Safety Hazard for Astronauts on EVA (ISS-EVA-312-4A_revE). The safety hazard identified the risk for an astronaut to experience an electrical shock in the event an arc was generated on an extravehicular mobility unit (EMU) surface. A catastrophic safety hazard, by the ISS requirements, necessitates mitigation by a two-fault tolerant system of hazard controls. Traditionally, the plasma contactor units (PCUs) on the ISS have been used to limit the charging and serve as a "ground strap" between the ISS structure and the surrounding ionospheric plasma. In 2009, a previous NASA Engineering and Safety Center (NESC) team evaluated the PCU utilization plan (NESC Request #07-054-E) with the objective to assess whether leaving PCUs off during non-EVA time periods presented risk to the ISS through assembly completion. For this study, in situ measurements of ISS charging, covering the installation of three of the four photovoltaic arrays, and laboratory testing results provided key data to underpin the assessment. The conclusion stated, "there appears to be no significant risk of damage to critical equipment nor excessive ISS thermal coating damage as a result of eliminating PCU operations during non- EVA times." In 2013, the ISSP was presented with recommendations from Boeing Space Environments for the "Conditional" Marginalization of Plasma Hazard. These recommendations include a plan that would keep the PCUs off during EVAs when the

  10. The American Gas Centrifuge Past, Present, and Future

    Energy Technology Data Exchange (ETDEWEB)

    Waters, Dean

    2004-09-15

    The art of gas centrifugation was born in 1935 at the University of Virginia when Dr. Jesse Beams demonstrated experimentally the separation of chlorine isotopes using an ultra-high speed centrifuge. Dr. Beam’s experiment initiated work that created a rich history of scientific and engineering accomplishment in the United States in the art of isotope separation and even large scale biological separation by centrifugation. The early history of the gas centrifuge development was captured in a lecture and documented by Dr. Jesse Beams in 1975. Much of Dr. Beams lecture material is used in this paper up to the year 1960. Following work by Dr. Gernot Zippe at the University of Virginia between 1958 and 1960, the US government embarked on a centrifuge development program that ultimately led to the start of construction of the Gas Centrifuge Enrichment Plant in Piketon Ohio in the late 1970’s. The government program was abandoned in 1985 after investing in the construction of two of six planned process buildings, a complete supply chain for process and centrifuge parts, and the successful manufacture and brief operation of an initial complement of production machines that would have met 15 percent of the planned capacity of the constructed process buildings. A declining market for enriched uranium, a glut of uranium enrichment capacity worldwide, and the promise of a new laser based separation process factored in the decision to stop the government program. By the late 1990’s it had become evident that gas centrifugation held the best promise to produce enriched uranium at low cost. In1999, the United States Enrichment Corporation undertook an initiative to revive the best of the American centrifuge technology that had been abandoned fourteen years earlier. This is an exciting story and one that when complete will enable the United States to maintain its domestic supply and to be highly competitive in the world market for this important energy commodity. (auth)

  11. Separation of Nanoparticles in Aqueous Multiphase Systems through Centrifugation

    KAUST Repository

    Akbulut, Ozge

    2012-08-08

    This paper demonstrates the use of aqueous multiphase systems (MuPSs) as media for rate-zonal centrifugation to separate nanoparticles of different shapes and sizes. The properties of MuPSs do not change with time or during centrifugation; this stability facilitates sample collection after separation. A three-phase system demonstrates the separation of the reaction products (nanorods, nanospheres, and large particles) of a synthesis of gold nanorods, and enriches the nanorods from 48 to 99% in less than ten minutes using a benchtop centrifuge. © 2012 American Chemical Society.

  12. Intermittent Flow of Granular Matter in an Annular Geometry

    Science.gov (United States)

    Brzinski, Ted; Daniels, Karen E.

    Granular solids can be subjected to a finite stress below which the response is elastic. Above this yield stress, however, the material fails catastrophically, undergoing a rapid plastic deformation. In the case of a monotonically increasing stress the material exhibits a characteristic stick-slip response. We investigate the statistics of this intermittent failure in an annular shear geometry, driven with a linear-ramp torque in order to generate the stick-slip behavior. The apparatus is designed to allow visual access to particle trajectories and inter-particle forces (through the use of photoelastic materials). Additionally, twelve piezoelectric sensors at the outer wall measure acoustic emissions due to the plastic deformation of the material. We vary volume fraction, and use both fixed and deformable boundaries. We measure how the distribution of slip size and duration are related to the bulk properties of the packing, and compare to systems with similar governing statistics.

  13. Dynamic Response of Three-Layered Annular Plate with Imperfections

    Directory of Open Access Journals (Sweden)

    Pawlus Dorota

    2015-02-01

    Full Text Available This paper presents the imperfection sensitivity of annular plate with three-layered structure. The plate composed of thin elastic facings and a thicker elastic core is loaded in facing plane. The classical issue of a three-layered plate was solved for dynamic deflection problem using the approximation methods: orthogonalization and finite difference. The solution includes the axisymmetric and asymmetric plate modes of the dynamic stability loss. The evaluation of the rate of plate sensitivity to imperfection of plate preliminary geometry has been enriched by the analysis of plate models built of finite elements. The ABAQUS program has been used. The numerous calculation results in the form of deflection characteristics, buckling modes, values of critical parameters create the view of response of dynamic plate structure with different rate of imperfection and linear in time loading growth, too.

  14. Fast High Capacity Annular Gas Puff Valve Design Concept

    Science.gov (United States)

    Ruden, Edward

    2000-10-01

    A fast opening gas valve design concept is presented that can theoretically inject a few grams of D2 gas radially outward into a coaxial annular vacuum region with a radius of about 10 cm in less that 100 μ s. The concept employs a single turn 20-30 T pulsed magnetic field coil that axially accelerates an Mg alloy ring, which seals a gas plenum, to high velocity, releasing the gas. Both coil and ring are profiled to minimize stress in the ring. Such a device could be used to supply the initial gas load for a proposed 5 MJ Dense Plasma Focus driven by AFRL's Shiva Star Capacitor bank. The intent here is keep the vacuum current feed insulator under high vacuum during the discharge to avoid surface breakdown. Alternatively, a high energy rep ratable plasma flow opening switch could be supplied with such a valve. This work is funded by the USAF.

  15. Two-phase flow instabilities in a vertical annular channel

    Energy Technology Data Exchange (ETDEWEB)

    Babelli, I.; Nair, S.; Ishii, M. [Purdue Univ., West Lafayette, IN (United States)

    1995-09-01

    An experimental test facility was built to study two-phase flow instabilities in vertical annular channel with emphasis on downward flow under low pressure and low flow conditions. The specific geometry of the test section is similar to the fuel-target sub-channel of the Savannah River Site (SRS) Mark 22 fuel assembly. Critical Heat Flux (CHF) was observed following flow excursion and flow reversal in the test section. Density wave instability was not recorded in this series of experimental runs. The results of this experimental study show that flow excursion is the dominant instability mode under low flow, low pressure, and down flow conditions. The onset of instability data are plotted on the subcooling-Zuber (phase change) numbers stability plane.

  16. Stability of Three-Layered Annular Plate with Composite Facings

    Science.gov (United States)

    Pawlus, D.

    2017-02-01

    Paper presents the behaviour of three-layered annular plates subjected to loads acting in plate plane. Plates are composed of laminated fibre-reinforced composite facings and foam core. The static and dynamic parameters of plate critical state were evaluated. The sensitivity of composite structure of plate to the acting of quickly increasing in time loads is shown. The problem has been solved numerically using the finite element method. Results have been compared with ones obtained for plate models with isotropic layers. These plate models have also been calculated solving formulated task analytically and numerically by means of the finite difference method. Solutions to the problem concern the axisymmetrical and asymmetrical plate buckling modes. Numerous presented tables and figures create the image of the stability behaviour of examined composite plates.

  17. A Novel Design of Magnetorheological Damper with Annular Radial Channel

    Directory of Open Access Journals (Sweden)

    Shisha Zhu

    2016-01-01

    Full Text Available With the development of automotive vibration technology, the semiactive suspension system with adjustable damping force and high reliability is taken seriously. The magnetorheological damper (MRD that applies intelligent material (magnetorheological fluid is the key element of this system. It can achieve a continuous and adjustable damping and then reaches the purpose of comfort. In order to improve the damping effect of MRD, this paper presents a MRD, which has magnetorheological (MR effect along annular radial channel. The paper completely designs the structure and magnetic circuit of MRD. Based on the theory of electromagnetism and MR fluid dynamics, the paper analyzes and tests the external characteristics of the MRD by the MATLAB/Simulink and the vibration experiment. The results compared with ordinary MRD reveal that the damping force obviously increases and has wide adjustable range, thus verifying the reasonableness of the damper design.

  18. Development of annular targets for {sup 99}MO production.

    Energy Technology Data Exchange (ETDEWEB)

    Conner, C.; Lewandowski, E. F.; Snelgrove, J. L.; Liberatore, M. W.; Walker, D. E.; Wiencek, T. C.; McGann, D. J.; Hofman, G. L.; Vandegrift, G. F.

    1999-09-30

    The new annular target performed well during irradiation. The target is inexpensive and provides good heat transfer during irradiation. Based on these and previous tests, we conclude that targets with zirconium tubes and either nickel-plated or zinc-plated foils work well. We proved that we could use aluminum target tubes, which are much cheaper and easier to work with than the zirconium tubes. In aluminum target tubes nickel-plated fission-recoil barriers work well and prevent bonding of the foil to the new target tubes during irradiation. Also, zinc-plated and aluminum-foil barriers appear promising in anodized aluminum tubes. Additional tests are anticipated to address such issues as fission-recoil barrier thickness and uranium foil composition. Overall, however, the target was successful and will provide an inexpensive, efficient way to irradiate LEU metal foil for the production of {sup 99}Mo.

  19. Annular elastolytic giant cell granuloma of conjunctiva: A case report

    Directory of Open Access Journals (Sweden)

    Karabi Konar

    2014-01-01

    Full Text Available Annular elastolytic giant cell granuloma is a condition characterized histologically by damaged elastic fibers associated with preponderance of giant cells along with absence of necrobiosis, lipid, mucin, and pallisading granuloma. It usually occurs on sun-damaged skin and hence the previous name actinic granuloma. A similar process occurs on the conjunctiva. Over the past three decades only four cases of conjunctival actinic granuloma have been documented. All the previous patients were females with lesions in nasal or temporal bulbar conjunctiva varying 2-3 mm in size. We report a male patient aged 70 years presenting with a 14 mm × 7 mm fleshy mass on right lower bulbar conjunctiva. Clinical differential diagnoses were lymphoma, squamous cell carcinoma in situ and amyloidosis. Surgical excision followed by histopathology confirmed it to be a case of actinic granuloma. This is the first case of isolated conjunctival actinic granuloma of such a large size reported from India.

  20. Fluxons in long and annular intrinsic Josephson junction stacks

    Science.gov (United States)

    Clauss, T.; Oehmichen, V.; Mößle, M.; Müller, A.; Weber, A.; Koelle, D.; Kleiner, R.

    2002-12-01

    A promising approach towards a THz oscillator based on intrinsic Josephson junctions in high-temperature superconductors is based on the collective motion of Josephson fluxons, which are predicted to form various configurations ranging from a triangular to a quadratic lattice. Not only for this reason, but certainly also for the sake of basic physics, several experimental and theoretical investigations have been done on the subject of collective fluxon dynamics in stacked intrinsic Josephson junctions. In this paper we will present some experimental results on the fluxon dynamics of long intrinsic Josephson junction stacks made of Bi2Sr2CaCu2O8. The stacks were formed either in an open or in an annular geometry, and clear resonant fluxon modes were observed. Experiments discussed include measurements of current-voltage characteristics in external magnetic fields and in external microwave fields.

  1. Geometry-Driven Folding of a Floating Annular Sheet.

    Science.gov (United States)

    Paulsen, Joseph D; Démery, Vincent; Toga, K Buğra; Qiu, Zhanlong; Russell, Thomas P; Davidovitch, Benny; Menon, Narayanan

    2017-01-27

    Predicting the large-amplitude deformations of thin elastic sheets is difficult due to the complications of self contact, geometric nonlinearities, and a multitude of low-lying energy states. We study a simple two-dimensional setting where an annular polymer sheet floating on an air-water interface is subjected to different tensions on the inner and outer rims. The sheet folds and wrinkles into many distinct morphologies that break axisymmetry. These states can be understood within a recent geometric approach for determining the gross shape of extremely bendable yet inextensible sheets by extremizing an appropriate area functional. Our analysis explains the remarkable feature that the observed buckling transitions between wrinkled and folded shapes are insensitive to the bending rigidity of the sheet.

  2. Performance of annular flow sterilizer irradiated by a germicidal lamp

    Energy Technology Data Exchange (ETDEWEB)

    Sugawara, T.; Yoneya, M.; Ohashi, H. (Akita Univ. (Japan))

    1981-10-01

    Theoretical and experimental studies were conducted on the UV-inactivation characteristics of Bacillus subtilis spores in an annular-flow sterilizer irradiated by a germicidal lamp located at the center of the inner tube. Experimental results for sterilizer performance in laminar spore-suspension flow were well simulated dynamically and statically by theoretical considerations which incorporated multi-targets with single-hit model for the UV-inactivation kinetic and the diffuse light model for the angle characteristic of lamp, along with due attention to the parabolic velocity distribution and the negligible diffusion of spores. Scale on the outside wall of the inner tube was checked by the use of a cylindrical chemical actinometer. Calculated examples elucidate the reason why careful inspection is needed of UV-inactivation kinetics, angle characteristics of lamp, and fluid mixing to evaluate performance of actual flow UV sterilizers at high extent of inactivation up to the order of 99.999%.

  3. Design of an Annular Disc Subject to Thermomechanical Loading

    Directory of Open Access Journals (Sweden)

    Sergei Alexandrov

    2012-01-01

    Full Text Available Two solutions to design a thin annular disc of variable thickness subject to thermomechanical loading are proposed. It is assumed that the thickness of the disc is everywhere sufficiently small for the stresses to be averaged through the thickness. The state of stress is plane. The initiation of plastic yielding is controlled by Mises yield criterion. The design criterion for one of the solutions proposed requires that the distribution of stresses is uniform over the entire disc. In this case there is a relation between optimal values of the loading parameters at the final stage. The specific shape of the disc corresponds to each pair of such parameters. The other solution is obtained under the additional requirement that the distribution of strains is uniform. This solution exists for the disc of constant thickness at specific values of the loading parameters.

  4. Distinct annular oligomers captured along the assembly and disassembly pathways of transthyretin amyloid protofibrils.

    Directory of Open Access Journals (Sweden)

    Ricardo H Pires

    Full Text Available BACKGROUND: Defects in protein folding may lead to severe degenerative diseases characterized by the appearance of amyloid fibril deposits. Cytotoxicity in amyloidoses has been linked to poration of the cell membrane that may involve interactions with amyloid intermediates of annular shape. Although annular oligomers have been detected in many amyloidogenic systems, their universality, function and molecular mechanisms of appearance are debated. METHODOLOGY/PRINCIPAL FINDINGS: We investigated with high-resolution in situ atomic force microscopy the assembly and disassembly of transthyretin (TTR amyloid protofibrils formed of the native protein by pH shift. Annular oligomers were the first morphologically distinct intermediates observed in the TTR aggregation pathway. Morphological analysis suggests that they can assemble into a double-stack of octameric rings with a 16 ± 2 nm diameter, and displaying the tendency to form linear structures. According to light scattering data coupled to AFM imaging, annular oligomers appeared to undergo a collapse type of structural transition into spheroid oligomers containing 8-16 monomers. Disassembly of TTR amyloid protofibrils also resulted in the rapid appearance of annular oligomers but with a morphology quite distinct from that observed in the assembly pathway. CONCLUSIONS/SIGNIFICANCE: Our observations indicate that annular oligomers are key dynamic intermediates not only in the assembly but also in the disassembly of TTR protofibrils. The balance between annular and more compact forms of aggregation could be relevant for cytotoxicity in amyloidogenic disorders.

  5. Research on the Release Characteristics of Marine DC Contactor%船用直流接触器脱扣特性的研究

    Institute of Scientific and Technical Information of China (English)

    陆干文; 韩露; 彭格; 袁征; 王永鑫

    2009-01-01

    论述了直流接触器脱扣原理,分析了影响直流接触器正确脱扣的主要因素,以三维有限元分析为基础,采用ANSYS软件仿真分析,提出一种减小铁心剩磁吸力的方法,保证船用接触器断电后可靠释放,提高了船用直流接触器的可靠性.%The principle of the release characteristics on marine DC eontaetor was surveyed and the main fac-tors which impact DC contactor correct release were analyzed.Based on 3D finite element method,by ANSYS soft-ware,a way to reduce residual flux force was introduced to ensure the DC eontactor release correctly.The reliability of marine DC contactor was impmved.

  6. Discussion on Usage of Contactor in Distribution Circuit of Frequency Converter%变频器配电回路中接触器的用法探讨

    Institute of Scientific and Technical Information of China (English)

    王婧; 黄岩; 刘学忠; 张风友

    2015-01-01

    针对目前在变频器配电回路设计中,对接触器用法存在的一些争议进行分析讨论,包括在输入侧和输出侧使用接触器的原因,以及操作中需要注意的问题等,并结合实际案例进行分析,给出解决该问题的一般性原则。%Analysis and discussion have been made for some disputes about the usage of contactor in current design for distribution circuit of frequency converter, including the reason for using contactor at input side and output side and considerations during operation; actual cases are analyzed and general principles for solving such problem are offered.

  7. 船用真空接触器合闸速度研究%Research on Marine Vacuum Contactor Closing Speed

    Institute of Scientific and Technical Information of China (English)

    余晓松

    2015-01-01

    结合现有船用真空接触器样机,在分析船用真空接触器合闸机理的基础上,对影响船用真空接触器性能关键的合闸速度进行了理论分析和设计校核。通过试验验证,表明合闸速度满足设计要求。%Combined with the existing marine vacuum contactor prototype and based on analysis of the closing operations mechanism of marine vacuum contactor,this paper did some theoretical research and design proof on the closing speed of affecting the marine vacuum contactor’s characteristics and verified by experiment that the closing speed can meet the design requirements.

  8. 转换型接触器/继电器应用中的误区%Some Misunderstandings on Transfer Contactor and Relay Application

    Institute of Scientific and Technical Information of China (English)

    崔子南; 朱黔; 杨英奕; 夏瑞

    2014-01-01

    通过三个具有代表性的案例,介绍了单刀双掷或双刀双掷转换型接触器/继电器在电气控制电路中存在的隐患。分析了隐患产生的原因,并就如何正确使用转换型接触器/继电器提出了建议。%Three representative cases were presented in this article.Hidden troubles in the electric control circuit of single pole double throw or double pole double throw transfer contactor and relay were presented.Suggestions on how to use single pole double throw or double pole double throw transfer contactor and relay correctly were proposed.

  9. Liquid-phase membrane extraction of targeted pesticides from manufacturing wastewaters in a hollow fibre contactor with feed-stream recycle.

    Science.gov (United States)

    Đorđević, Jelena; Vladisavljević, Goran T; Trtić-Petrović, Tatjana

    2017-01-01

    A two-phase membrane extraction in a hollow fibre contactor with feed-stream recycle was applied to remove selected pesticides (tebufenozide, linuron, imidacloprid, acetamiprid and dimethoate) from their mixed aqueous solutions. The contactor consisted of 50 polypropylene hollow fibres impregnated with 5% tri-n-octylphosphine oxide in di-n-hexyl ether. For low-polar pesticides with log P ≥ 2 (tebufenozide and linuron), the maximum removal efficiency increased linearly from 85% to 96% with increasing the feed flow rate. The maximum removal efficiencies of more polar pesticides were significantly higher under feed recirculation (86%) than in a continuous single-pass operation (30%). It was found from the Wilson's plot that the mass transfer resistance of the liquid membrane can be neglected for low-polar pesticides. The pesticide removals from commercial formulations were similar to those from pure pesticide solutions, indicating that built-in adjuvants did not affect the extraction process.

  10. 交流接触器自动检测系统设计%Design of Automatic Detecting System of AC Contactor

    Institute of Scientific and Technical Information of China (English)

    李林; 强秀华; 邹斌

    2012-01-01

    针对交流接触器传统检测方法存在的缺点,设计了交流接触器自动检测系统.首先,对检测流程和设计要求做了说明;然后,给出了数据采集程序和PLC程序流程图.结果表明,该系统运行可靠,检测精度高,达到了规定的设计目标.%Focused on the defects of the traditional method of detecting for AC contactor, the paper designed the auto-matic detecting system of AC contactor. Firstly detecting process and design requirements were introduced, secondly the software flowchart of data acquisition program and PLC program were given. The results showed that this automatic detec-ting runs reliably and has high accuracy, it achieves the required goals and designed requirements.

  11. 一种高可靠性辅助触头设计与验证%Design and Verification of the Auxiliary Contactor with High Reliability

    Institute of Scientific and Technical Information of China (English)

    陈伟刚

    2015-01-01

    Against the current status of the poor reliability of the auxiliary contactors in low voltage electric appliances, the auxiliary contactor with double contacts that can laterally sliding is designed. The structure of double contacts can effectively reduce the beam current resistance, and the lateral sliding friction can effectively eliminate the dirt and oxide layers on surface of the contacts to reduce the membrane resistance. In addition, the simulation analysis for different types of the contact bridges is carried out, thus better structure of the contact bridge is obtained. The test results verify that the high reliable auxiliary contactor can effectively enhance the making capacity for small load, this provides certain reference to the design and optimization of the auxiliary contactors in low voltage electric appliances.%针对低压电器辅助触头可靠性差的现状,设计了一种双触点可横向滑动的辅助触头。其双触点结构可以有效降低束流电阻;横向滑动产生的滑动摩擦可以有效去除触点表面脏物和氧化层,降低触头接触的膜电阻。此外,对不同形式的触桥进行了仿真分析,获得了较优化的触桥结构。实测结果验证了高可靠性辅助触头可以有效提高小负载接通能力,从而为低压电器中辅助触头组的设计和优化提供相应参考。

  12. [Evaluation of high-efficiency gas-liquid contactors for natural gas processing]. Semiannual technical progress report, October 1, 1992--March 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-01

    The objective of this proposed program is to evaluate the potential of rotating gas-liquid contactors for natural gas processing by expanding the currently available database. This expansion will focus on application of this technology to environments representative of those typically encountered in natural gas processing plants. Operational and reliability concerns will be addressed while generating pertinent engineering data relating to the mass-transfer process. This report presents results on fluid dynamics and mass transfer coefficient studies.

  13. 膜接触器在环境治理中的应用研究进展%Novel Membrane Contactors and Their Application in Environmental Protection

    Institute of Scientific and Technical Information of China (English)

    李娜; 盛新江; 马青兰; 张国亮; 王家德

    2011-01-01

    In a novel membrane contactor, separation is efficiently integrated with conventional chemical separation technology, which achieves gas/liquid or liquid/liquid mass transfer without dispersion of one phase with another. After the first successful industrial installations, different kinds of membrane contactors have found important applications in environmental protection such as aromatics recovery from a process water, selective removal of heavy metals from an industrial process and recovery of ammonia, CO2 and H2S from an off gas stream. Principle of several typical membrane contactors were introduced, including membrane distillation, membrane adsorption, membrane extraction and membrane structured packing. Characteristics of material used in typical membrane contactors were also discussed.%膜接触器是将膜分离和传统化工单元操作有机结合而成的一种新型高效分离器,可不通过两相的直接接触而实现相间传质.继21世纪初首个工业化实例成功以来,在废水中芳香族化合物脱除、重金属选择吸收、废气中氨、CO2、H2S去除等多个领域的环境治理中,膜接触器技术的研究与应用日益重要.在此基础上,文章对膜蒸馏、膜吸收、膜萃取和膜填料替代等膜接触器技术的作用机理进行了比较,重点阐述了其在环境治理中的应用和发展状况,并对典型接触器中膜材料的性能和特点进行了分析.

  14. Mathematical modeling of liquid/liquid hollow fiber membrane contactor accounting for interfacial transport phenomena: Extraction of lanthanides as a surrogate for actinides

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, J.D.

    1994-08-04

    This report is divided into two parts. The second part is divided into the following sections: experimental protocol; modeling the hollow fiber extractor using film theory; Graetz model of the hollow fiber membrane process; fundamental diffusive-kinetic model; and diffusive liquid membrane device-a rigorous model. The first part is divided into: membrane and membrane process-a concept; metal extraction; kinetics of metal extraction; modeling the membrane contactor; and interfacial phenomenon-boundary conditions-applied to membrane transport.

  15. Failure analysis of a polymer centrifugal impeller

    Directory of Open Access Journals (Sweden)

    Nikhil K. Kar

    2015-10-01

    Full Text Available A failure analysis investigation was performed on a fractured polymer impeller used in a respiratory blower. Light microscopy, scanning electron microscopy and finite element analysis techniques were utilized to characterize the mode(s of failure and fracture surfaces. A radial split down the impeller center was observed with symmetric fracture faces about the impeller bore. Fractographic analysis revealed brittle fracture features including Wallner lines, mirror, mist and hackle features stemming from the impeller bore, emanating radially outward. Crazed fibrils and faint fatigue striations suggest that intermittent load cycling led to initiation, and rapid propagation of multiple crack fronts originating along the impeller lip. Finite element analysis revealed a flexural condition induces localized stresses along the impeller lip. Significant wear features were also observed within the impeller bore, which may have contributed to premature failure of the impeller. The brittle fracture morphology and defects within the impeller bore suggest that premature failure occurred because of multiple interacting factors including: intermittently high centrifugal velocities, imbalance bore and shaft conditions, defects within the bore caused by machining, and stress concentrations along the circumference of the impeller lip.

  16. Central centrifugal cicatricial alopecia: challenges and solutions

    Directory of Open Access Journals (Sweden)

    Herskovitz I

    2016-08-01

    Full Text Available Ingrid Herskovitz, Mariya Miteva Department of Dermatology and Cutaneous Surgery, University of Miami L Miller School of Medicine, Miami, FL, USA Abstract: Central centrifugal cicatricial alopecia (CCCA is the most common scarring alopecia among African American women. Data about epidemiology, etiology, genetic inheritance, and management are scarce and come from individual reports or small series. CCCA has been associated with hot combing and traumatic hair styling for years; however, studies fail to confirm it as the sole etiologic factor. It has been shown in a small series that CCCA can be inherited in an autosomal dominant fashion, with a partial penetrance and a strong modifying effect of hairstyling and sex. CCCA presents clinically as a central area of progressive irreversible hair loss that expands to the periphery. A patchy form has also been described. Dermoscopy is helpful to identify the optimal site for the biopsy, which establishes the diagnosis. Well-designed randomized controlled trials are needed to discover the optimal management. At this point, patients are advised to avoid traction and chemical treatments; topical and intralesional steroids, calcineurin inhibitors, and minoxidil can be helpful in halting the progression. Keywords: hair loss, alopecia, dermatoscopy, dermoscopy, trichoscopy, black scalp, African American, scarring alopecia

  17. Central centrifugal cicatricial alopecia: challenges and solutions.

    Science.gov (United States)

    Herskovitz, Ingrid; Miteva, Mariya

    2016-01-01

    Central centrifugal cicatricial alopecia (CCCA) is the most common scarring alopecia among African American women. Data about epidemiology, etiology, genetic inheritance, and management are scarce and come from individual reports or small series. CCCA has been associated with hot combing and traumatic hair styling for years; however, studies fail to confirm it as the sole etiologic factor. It has been shown in a small series that CCCA can be inherited in an autosomal dominant fashion, with a partial penetrance and a strong modifying effect of hairstyling and sex. CCCA presents clinically as a central area of progressive irreversible hair loss that expands to the periphery. A patchy form has also been described. Dermoscopy is helpful to identify the optimal site for the biopsy, which establishes the diagnosis. Well-designed randomized controlled trials are needed to discover the optimal management. At this point, patients are advised to avoid traction and chemical treatments; topical and intralesional steroids, calcineurin inhibitors, and minoxidil can be helpful in halting the progression.

  18. On the Motion of an Annular Film in Microgravity Gas-Liquid Flow

    Science.gov (United States)

    McQuillen, John B.

    2002-01-01

    Three flow regimes have been identified for gas-liquid flow in a microgravity environment: Bubble, Slug, and Annular. For the slug and annular flow regimes, the behavior observed in vertical upflow in normal gravity is similar to microgravity flow with a thin, symmetrical annular film wetting the tube wall. However, the motion and behavior of this film is significantly different between the normal and low gravity cases. Specifically, the liquid film will slow and come to a stop during low frequency wave motion or slugging. In normal gravity vertical upflow, the film has been observed to slow, stop, and actually reverse direction until it meets the next slug or wave.

  19. Characterization of annular two-phase gas-liquid flows in microgravity

    Science.gov (United States)

    Bousman, W. Scott; Mcquillen, John B.

    1994-01-01

    A series of two-phase gas-liquid flow experiments were developed to study annular flows in microgravity using the NASA Lewis Learjet. A test section was built to measure the liquid film thickness around the perimeter of the tube permitting the three dimensional nature of the gas-liquid interface to be observed. A second test section was used to measure the film thickness, pressure drop and wall shear stress in annular microgravity two-phase flows. Three liquids were studied to determine the effects of liquid viscosity and surface tension. The result of this study provide insight into the wave characteristics, pressure drop and droplet entrainment in microgravity annular flows.

  20. An analytical model for annular flow boiling heat transfer in microchannel heat sinks

    Energy Technology Data Exchange (ETDEWEB)

    Megahed, A.; Hassan, I. [Concordia University, Montreal, QC (Canada). Dept. of Mechanical and Industrial Engineering

    2009-07-01

    An analytical model has been developed to predict flow boiling heat transfer coefficient in microchannel heat sinks. The new analytical model is proposed to predict the two-phase heat transfer coefficient during annular flow regime based on the separated model. Opposing to the majority of annular flow heat transfer models, the model is based on fundamental conservation principles. The model considers the characteristics of microchannel heat sink during annular flow and eliminates using any empirical closure relations. Comparison with limited experimental data was found to validate the usefulness of this analytical model. The model predicts the experimental data with a mean absolute error 8%. (author)

  1. Tight focus of a radially polarized and amplitudemodulated annular multi-Gaussian beam

    Institute of Scientific and Technical Information of China (English)

    Chen Jian-Nong; Xu Qin-Feng; Wang Gang

    2011-01-01

    The focusing of a radially polarized beam without annular apodization ora phase filter at the entrance pupil of the objective results in a wide focus and low purity of the longitudinally polarized component.However,the presence of a physical annular apodization or phase filter makes some applications more difficult or even impossible.We propose a radially polarized and amplitude-modulated annular multi-Gaussian beam mode.Numerical simulation shows that it can be focused into a sharper focal spot of 0.125λ2 without additional apodizations or filters.The beam quality describing the purity of longitudinally polarized component is up to 86%.

  2. Centrifuging Step-Screw Conveyor for Regolith Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A variety of ISRU operations will utilize lunar regolith as feedstock. The proposed centrifuging step-screw conveyor concept will provide a well controlled robust,...

  3. MULTIOBJECT OPTIMIZATION OF A CENTRIFUGAL IMPELLER USING EVOLUTIONARY ALGORITHMS

    Institute of Scientific and Technical Information of China (English)

    Li Jun; Liu Lijun; Feng Zhenping

    2004-01-01

    Application of the multiobjective evolutionary algorithms to the aerodynamic optimization design of a centrifugal impeller is presented. The aerodynamic performance of a centrifugal impeller is evaluated by using the three-dimensional Navier-Stokes solutions. The typical centrifugal impeller is redesigned for maximization of the pressure rise and blade load and minimization of the rotational total pressure loss at the given flow conditions. The B閦ier curves are used to parameterize the three-dimensional impeller blade shape. The present method obtains many reasonable Pareto optimal designs that outperform the original centrifugal impeller. Detailed observation of the certain Pareto optimal design demonstrates the feasibility of the present multiobjective optimization method tool for turbomachinery design.

  4. TECHNOLOGY EVALUATION REPORT: RETECH'S PLASMA CENTRIFUGAL FURNACE - VOLUME I

    Science.gov (United States)

    A demonstration of the Retech, Inc. Plasma Centrifugal Furnace (PCF) was conducted under the Superfund Innovative Technology Evaluation (SITE) Program at the Department of Energy's (DOE's) Component Development and Integration Facility in Butte, Montana. The furnace uses heat gen...

  5. Comparative analysis of discrete exosome fractions obtained by differential centrifugation

    DEFF Research Database (Denmark)

    Jeppesen, Dennis Kjølhede; Hvam, Michael L; Primdahl-Bengtson, Bjarke

    2014-01-01

    BACKGROUND: Cells release a mixture of extracellular vesicles, amongst these exosomes, that differ in size, density and composition. The standard isolation method for exosomes is centrifugation of fluid samples, typically at 100,000×g or above. Knowledge of the effect of discrete...... ultracentrifugation speeds on the purification from different cell types, however, is limited. METHODS: We examined the effect of applying differential centrifugation g-forces ranging from 33,000×g to 200,000×g on exosome yield and purity, using 2 unrelated human cell lines, embryonic kidney HEK293 cells and bladder...... of phenol red and cleared by 200,000×g overnight centrifugation. The centrifugation tube fill level impacted the sedimentation efficacy. Comparative analysis by NTA, protein quantification, and detection of exosomal and contamination markers identified differences in vesicle size, concentration...

  6. Confusion around the tidal force and the centrifugal force

    CERN Document Server

    Matsuda, Takuya; Boffin, Henri M J

    2015-01-01

    We discuss the tidal force, whose notion is sometimes misunderstood in the public domain literature. We discuss the tidal force exerted by a secondary point mass on an extended primary body such as the Earth. The tidal force arises because the gravitational force exerted on the extended body by the secondary mass is not uniform across the primary. In the derivation of the tidal force, the non-uniformity of the gravity is essential, and inertial forces such as the centrifugal force are not needed. Nevertheless, it is often asserted that the tidal force can be explained by the centrifugal force. If we literally take into account the centrifugal force, it would mislead us. We therefore also discuss the proper treatment of the centrifugal force.

  7. Manufacture of hollow ingots using centrifugal casting machines

    Science.gov (United States)

    Pomeshchikov, A. G.; Greneva, T. S.; Baidachenko, V. I.; Berezin, V. I.

    2010-12-01

    Centrifugal machines are proposed for the foundry created at the Almalyk Mining and Smelting Factory in order to produce hollow ingots of a liquid metal made by remelting of consumable electrodes in a refractory accumulating crucible.

  8. DESIGN AND FABRICATION OF A CENTRIFUGAL CASTING MACHINE

    Directory of Open Access Journals (Sweden)

    Adedipe Oyewole

    2011-12-01

    Full Text Available The design and fabrication of a centrifugal casting machine was successfully carried out. The operation of the machine was based on the principle of centrifugal force. Suitable design theory, analysis and calculation were adopted carried out in the course of the work. The mold is bolted to the base plate which can rotate at moderatespeeds thereby forcing the molten metal against the inner walls of the mold. This machine could be used to cast small engineering components. The centrifugal force on the machine was determined to be 3207.3N, while the required power on the machine was 854.7W. A test was carried out on the fabricated centrifugal casting machine with aluminum alloy and the machine was able to cast 6kg of aluminum alloy and the casting was successful.

  9. Fluent-based numerical simulation of flow centrifugal fan

    Institute of Scientific and Technical Information of China (English)

    LI Xian-zhang

    2011-01-01

    Testing centrifugal fan flow field by physical laboratory is difficult because the testing system is complex and the workload is heavy, and the results observed by naked-eye deviates far from the actual value. To address this problem, the computational fluid dynamics software FLUENT was applied to establish three-dimensional model of the centrifugal fan. The numeral model was verified by comparing simulation data to experimental data. The pressure centrifugal fan and the speed changes in distribution in centrifugal fan was simulated by computational fluid dynamics software FLUENT. The simulation results show that the gas flow velocity in the impeller increases with impeller radius increase. Static pressure gradually increases when gas from the fan access is imported through fan impeller leaving fans.

  10. Hollow Fiber Membrane Contactors for Post-Combustion CO2 Capture: A Scale-Up Study from Laboratory to Pilot Plant

    Directory of Open Access Journals (Sweden)

    Chabanon E.

    2014-11-01

    Full Text Available Membrane contactors have been proposed for decades as a way to achieve intensified mass transfer processes. Post-combustion CO2 capture by absorption into a chemical solvent is one of the currently most intensively investigated topics in this area. Numerous studies have already been reported, unfortunately almost systematically on small, laboratory scale, modules. Given the level of flue gas flow rates which have to be treated for carbon capture applications, a consistent scale-up methodology is obviously needed for a rigorous engineering design. In this study, the possibilities and limitations of scale-up strategies for membrane contactors have been explored and will be discussed. Experiments (CO2 absorption from a gas mixture in a 30%wt MEA aqueous solution have been performed both on mini-modules and at pilot scale (10 m2 membrane contactor module based on PTFE hollow fibers. The results have been modelled utilizing a resistance in series approach. The only adjustable parameter is in fitting the simulations to experimental data is the membrane mass transfer coefficient (km, which logically plays a key role. The difficulties and uncertainties associated with scaleup computations from lab scale to pilot scale modules, with a particular emphasis on the km value, are presented and critically discussed.

  11. Power Consumption, Mixing Time, and Oxygen Mass Transfer in a Gas-Liquid Contactor Stirred with a Dual Impeller for Different Spacing

    Directory of Open Access Journals (Sweden)

    Hayder Mohammed Issa

    2016-01-01

    Full Text Available Multiple or dual impellers are widely implemented in stirred contactors used in various biological processes like fermentation, water treatment, and pharmaceutical production. The spacing between impellers is considered as a crucial factor in designing of these types of contactors resulting in variation of oxygen mass transfer, mixing time, or power consumption for such biological system. A study of three parts was conducted to characterize the effect of the spacing between impellers on the most important parameters that related to biological contactor performance: oxygen mass transfer coefficient kla from the gas phase (air to the liquid phase (water, mixing time, and power consumption for different operating rotational speeds (1.67–3.33 rps and for three different spacing positions. The used impellers system in the study is a dual impeller system which consists of an inverted and bladed rotated cone (IBRC and a pitched-blade up-flow propeller (PBPU. The experimental results showed that the shorter spacing (the lower PBPU in a higher position is more convenient, as the achieved oxygen mass transfer coefficient has showed an improvement in its values with lower mixing time and with a slight alteration in power consumption.

  12. 对接触器干扰单片机系统的抑制%Inhibition of Contactor Interferences to Monolithic Microcomputer System

    Institute of Scientific and Technical Information of China (English)

    王昊; 那文鹏; 姚丽萍

    2001-01-01

    On the occasions of monolithic microcomputer and contactors are packed in one case, electromagnetic interferences, yielded by contactor coils as they are switched on or off, and spark interferences, generated by the pushbutton swi tches that control contactor coils as they are switched on or off, all make mono lith ic microcomputer application system work improperly. The article introduces inh ibiting methods such as phase splitting, TVP, resistive and capacitive absorbing , time delay and coupling removing.%当单片机与接触器装在同一箱体时,接触器线圈在通、断电时产生的电磁干扰 ,控制接触器线圈通电、断电的按钮开关在通、断电时产生的火花干扰,均使单片机应用系统不能正常工作。本文介绍了分相、TVP、阻容吸收、延时、去耦等抑制方法。

  13. 新型智能混合式交流接触器%A New Type of Hybrid Semiconductor Intelligent AC Contactor

    Institute of Scientific and Technical Information of China (English)

    张培铭; 陈从华; 郑昕

    2001-01-01

    介绍了一种新型的混合式智能交流接触器,其仅用2个单向晶闸管就实现了接触器的少弧或无弧运行,且大大降低成本,减少体积。该接触器实现了全过程的动态优化控制,达到了节能、节材、无噪声、高操作频率、高电寿命,且可与主控计算机进行双向通信。%A new-type hybrid semiconductor intelligent AC contactor was developed. In the contacts of this kind of contactor with two SCRs only will there be no arcing or just small arcing when they are broken. The cost and volume are reduced greatly. This contactor realizes the optimal control in dynamic process and brings the benefits of energy and materials saving, no noise, high operating frequency and high electrical endurance. And it can also be communicated with the central master computer.

  14. Novel Water Treatment Processes Based on Hybrid Membrane-Ozonation Systems: A Novel Ceramic Membrane Contactor for Bubbleless Ozonation of Emerging Micropollutants

    Directory of Open Access Journals (Sweden)

    Stylianos K. Stylianou

    2015-01-01

    Full Text Available The aim of this study is the presentation of novel water treatment systems based on ozonation combined with ceramic membranes for the treatment of refractory organic compounds found in natural water sources such as groundwater. This includes, firstly, a short review of possible membrane based hybrid processes for water treatment from various sources. Several practical and theoretical aspects for the application of hybrid membrane-ozonation systems are discussed, along with theoretical background regarding the transformation of target organic pollutants by ozone. Next, a novel ceramic membrane contactor, bringing into contact the gas phase (ozone and water phase without the creation of bubbles (bubbleless ozonation, is presented. Experimental data showing the membrane contactor efficiency for oxidation of atrazine, endosulfan, and methyl tert-butyl ether (MTBE are shown and discussed. Almost complete endosulfan degradation was achieved with the use of the ceramic contactor, whereas atrazine degradation higher than 50% could not be achieved even after 60 min of reaction time. Single ozonation of water containing MTBE could not result in a significant MTBE degradation. MTBE mineralization by O3/H2O2 combination increased at higher pH values and O3/H2O2 molar ratio of 0.2 reaching a maximum of around 65%.

  15. High-power test of annular-ring coupled structures for the J-PARC linac energy upgrade

    Science.gov (United States)

    Tamura, Jun; Ao, Hiroyuki; Nemoto, Yasuo; Asano, Hiroyuki; Suzuki, Takahiro

    2015-02-01

    Annular-ring coupled structures (ACSs) will increase the beam energy of the Japan proton accelerator research complex (J-PARC) linac from 181 to 400 MeV to achieve a beam power of 1 MW for a materials and life science experimental facility. The mass production of the ACS cavities commenced in March 2009. Before the installation, all cavities require power testing. High-power testing is essential not only for confirming the cavity's design performance but also for preventing delays in cavity conditioning schedule. However, the 2011 Tohoku earthquake damaged J-PARC facilities, including the ACS power-test area, and cavity conditioning was interrupted for two years. After the facility's restoration, two ACS cavities (M01 and M11) were conditioned. They performed 15-20% above the designed accelerating field of 4.2 MV/m. As M01 was initially conditioned six years ago, the most recent conditioning time required for M01 was drastically reduced. From this result, we confirmed that long-term stored ACS cavities purged with nitrogen gas do not produce critical cavity performance issues. During high-power operation of M11, which is a unique cavity equipped with a capacitive iris in a waveguide, no significant increases in the temperature and the discharge rate around the capacitive iris were observed. Even considering beam loss due to residual gas scattering, the vacuum pressure was sufficiently low (4 × 10-6 Pa). More stable operation can be expected following a month-long conditioning process before the beam is commissioned. M11's conditioning successfully demonstrated an auto-conditioning program, and we established the conditioning scheme using this auto-conditioning program for all ACS cavities in a limited time and with limited manpower.

  16. 21 CFR 862.2140 - Centrifugal chemistry analyzer for clinical use.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Centrifugal chemistry analyzer for clinical use... Instruments § 862.2140 Centrifugal chemistry analyzer for clinical use. (a) Identification. A centrifugal chemistry analyzer for clinical use is an automatic device intended to centrifugally mix a sample and...

  17. Rapid detection of simulated bacteremia by centrifugation and filtration.

    OpenAIRE

    Herlich, M B; Schell, R F; Francisco, M.; Le Frock, J L

    1982-01-01

    A centrifugation-filtration procedure was developed to expedite the recovery of microorganisms from blood. Fresh whole human blood was inoculated with various aerobic and facultatively anaerobic microorganisms (3 to 18 per ml). The seeded blood was carefully overlaid on a Ficoll-Hypaque gradient (density, 1.114 g/ml) and centrifuged (400 x g) for 45 min at ambient temperature. The entire gradient (plasma, leukocytes, and Ficoll-Hypaque) was removed and filtered through a 0.22-micrometer membr...

  18. CALCULATION AND IMPROVEMENT OF DYNAMIC CHARACTERISTICS OF CENTRIFUGE

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The modeling of the rotor-support system of a typical centrifuge is discussed. The impedance matching method, cooperating with Riccati transfer matrix method and modal analysis method are adopted to calculate its dynamic characteristics. The influences of the main parts to the critical speeds are analyzed. Based on the analysis, a critical speed in the operating speed range is tuned successfully, and thus the dynamic characteristics of the centrifuge are much improved.

  19. Synthesis and Analytical Centrifugation of Magnetic Model Colloids

    OpenAIRE

    Luigjes, B.

    2012-01-01

    This thesis is a study of the preparation and thermodynamic properties of magnetic colloids. First, two types of magnetic model colloids are investigated: composite colloids and single-domain nanoparticles. Thermodynamics of magnetic colloids is studied using analytical centrifugation, including a specially adapted centrifuge for measuring heavy and strongly light absorbing colloids. Magnetic composite colloids can be prepared from thermodynamically stable Pickering emulsions of 3-methacrylox...

  20. Centrifugal microfluidic platforms: advanced unit operations and applications.

    Science.gov (United States)

    Strohmeier, O; Keller, M; Schwemmer, F; Zehnle, S; Mark, D; von Stetten, F; Zengerle, R; Paust, N

    2015-10-01

    Centrifugal microfluidics has evolved into a mature technology. Several major diagnostic companies either have products on the market or are currently evaluating centrifugal microfluidics for product development. The fields of application are widespread and include clinical chemistry, immunodiagnostics and protein analysis, cell handling, molecular diagnostics, as well as food, water, and soil analysis. Nevertheless, new fluidic functions and applications that expand the possibilities of centrifugal microfluidics are being introduced at a high pace. In this review, we first present an up-to-date comprehensive overview of centrifugal microfluidic unit operations. Then, we introduce the term "process chain" to review how these unit operations can be combined for the automation of laboratory workflows. Such aggregation of basic functionalities enables efficient fluidic design at a higher level of integration. Furthermore, we analyze how novel, ground-breaking unit operations may foster the integration of more complex applications. Among these are the storage of pneumatic energy to realize complex switching sequences or to pump liquids radially inward, as well as the complete pre-storage and release of reagents. In this context, centrifugal microfluidics provides major advantages over other microfluidic actuation principles: the pulse-free inertial liquid propulsion provided by centrifugal microfluidics allows for closed fluidic systems that are free of any interfaces to external pumps. Processed volumes are easily scalable from nanoliters to milliliters. Volume forces can be adjusted by rotation and thus, even for very small volumes, surface forces may easily be overcome in the centrifugal gravity field which enables the efficient separation of nanoliter volumes from channels, chambers or sensor matrixes as well as the removal of any disturbing bubbles. In summary, centrifugal microfluidics takes advantage of a comprehensive set of fluidic unit operations such as

  1. Parameter Study of Melt Spun Polypropylene Fibers by Centrifugal Spinning

    Science.gov (United States)

    2014-07-01

    synthesis of C/Fe3O4 composite nanofibers and their application for high performance lithium-ion batteries . J Power Sources. 2008;83:717–723. 2. Zhang...spinning process . Eur Polym J. 2013;49:3834–3845. 9 1 DEFENSE TECHNICAL (PDF) INFORMATION CTR DTIC OCA 2 DIRECTOR (PDF) US ARMY RESEARCH...composites, and energy harvesting to tissue engineering and drug delivery. Centrifugal spinning is a new technique that uses centrifugal forces to form

  2. Design and Characterization of a Centrifugal Compressor Surge Test Rig

    OpenAIRE

    2011-01-01

    A detailed description of a new centrifugal compressor surge test rig is presented. The objective of the design and development of the rig is to study the surge phenomenon in centrifugal compression systems and to investigate a novel method of surge control by active magnetic bearing servo actuation of the impeller axial tip clearance. In this paper, we focus on the design, initial setup, and testing of the rig. The latter two include the commissioning of the rig and the experimental characte...

  3. Fabrication of Al/Diamond Particles Functionally Graded Materials by Centrifugal Sintered-Casting Method

    Science.gov (United States)

    Watanabe, Yoshimi; Shibuya, Masafumi; Sato, Hisashi

    2013-03-01

    The continuous graded structure of functionally graded materials (FGMs) can be created under a centrifugal force. Centrifugal sintered-casting (CSC) method, proposed by the authors, is one of the fabrication methods of FGM under centrifugal force. This method is a combination of the centrifugal sintering method and centrifugal casting method. In this study, Al/diamond particle FGM was fabricated by the proposed method.

  4. Analysis and design of digital control for AC contactors%交流接触器数字化控制的分析与设计

    Institute of Scientific and Technical Information of China (English)

    罗海海; 许志红

    2015-01-01

    Digital control is put forward into AC contactors with dsPIC .Coil supply circuit is modified from BUCK whose current can be closed -loop in real -time by digital PI or on/off.The dynamic attraction and counterforce of contactor fit well in making to reduce the bounce or collision of contact and core , so the lifetime of AC contactors prolonged .Cutting off the PWM , keeping coil current in a low to save energy and undo noise after making stable .In breaking , the negative-voltage is adopted to enhance the break speed .Entire process of contactors are simulated by PROTEUS to guide the design of intelligent module and the analysis of control scheme .It also verified by experiments , which show that the digital control is flexibility and universality to improve the performance of AC contactors .%提出了以dsPIC为控制核心的交流接触器数字化控制技术。对BUCK电路进行改造作为线圈供电主回路,分别利用数字PI和流限开/关,实现了线圈电流的闭环控制,使得吸合过程的吸反力合理配合,减小触头和铁芯的弹跳与碰撞,提高电寿命。可靠吸合后,切断PWM斩波信号,转入直流低压运行,能耗小、无噪声。分断时,采用负压控制,线圈能量被快速吸收,提高了接触器的分断速度。通过PROTEUS软件对吸合、吸持和分断过程进行仿真,有助于智能控制模块的设计及控制方案的分析。相关试验结果表明,数字化控制技术改善了交流接触器各项性能指标,具有较好灵活性、通用性。

  5. Biofilm Community Dynamics in Bench-Scale Annular Reactors Simulating Arrestment of Chloraminated Drinking Water Nitrification

    Science.gov (United States)

    Annular reactors (ARs) were used to study biofilm community succession and provide an ecological insight during nitrification arrestment through simultaneously increasing monochloramine (NH2Cl) and chlorine to nitrogen mass ratios, resulting in four operational periods (I to IV)....

  6. An iterative method for the solution of nonlinear systems using the Faber polynomials for annular sectors

    Energy Technology Data Exchange (ETDEWEB)

    Myers, N.J. [Univ. of Durham (United Kingdom)

    1994-12-31

    The author gives a hybrid method for the iterative solution of linear systems of equations Ax = b, where the matrix (A) is nonsingular, sparse and nonsymmetric. As in a method developed by Starke and Varga the method begins with a number of steps of the Arnoldi method to produce some information on the location of the spectrum of A. This method then switches to an iterative method based on the Faber polynomials for an annular sector placed around these eigenvalue estimates. The Faber polynomials for an annular sector are used because, firstly an annular sector can easily be placed around any eigenvalue estimates bounded away from zero, and secondly the Faber polynomials are known analytically for an annular sector. Finally the author gives three numerical examples, two of which allow comparison with Starke and Varga`s results. The third is an example of a matrix for which many iterative methods would fall, but this method converges.

  7. Effect of January 15, 2010 annular solar eclipse on meteorological parameters over Goa, India

    Digital Repository Service at National Institute of Oceanography (India)

    Muraleedharan, P.M.; Nisha, P.G.; Mohankumar, K.

    Atmospheric perturbations due to the annular solar eclipse were monitored to understand its influence on the meteorological parameters from surface to the lower stratosphere. A strong inversion at 13 km and an abnormal warming in the upper...

  8. Theoretical and Experimental Investigation of Ultrasonic Focusing with Annular Phased Array

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bi-Xing; WANG Cheng-Hao; LAI Pu-Xiang

    2006-01-01

    @@ The focused acoustic field generated by an annular array transducer and its reflection field on a solid-liquid interface are investigated theoretically and experimentally. Theoretically, the concise analytic expressions about the radiation and reflection acoustic fields of the annular phased array are obtained by the ray approach method (saddle-point method). In experiment, an annular transducer with 8 equal-area elements is designed and fabricated, and a series of experiments about the radiation acoustic field and its reflection on the liquid-solid interface are carried out. The experimental characteristics of the transducer are in good agreement with the numerical ones. It shows the correctness of the theoretical result and the feasibility of dynamic focusing of the experiment system. With the maximum amplitude and its emergence time of the reflection wave, we can acquire the information and the imaging of the reflection interface by the annular phased array dynamic focusing.

  9. Annular lichenoid dermatitis of youth--a further case in a 12-year-old girl.

    Science.gov (United States)

    Kleikamp, Stefanie; Kutzner, Heinz; Frosch, Peter J

    2008-08-01

    Annular lichenoid dermatitis of youth was first described by Annessi et al. in 2003. Clinical criteria are persistent erythematous macules and annular lesions with a red-brown edge and a central hypopigmentation usually found on the flanks and groins of children and adolescents. Histologically, the disease is characterized by a lichenoid interface dermatitis with necrotic keratinocytes at the tip of the rete ridges. In our case a 12-year old girl developed annular red-brown macules with papules at the borders in an inframammary location. The histology of the lesion's border showed a lichenoid lymphocytic infiltrate with apoptotic keratinocytes at the tip of rete ridges. The lesions cleared with 0.03% tacrolimus ointment. Annular lichenoid dermatitis of youth is probably a new entity in the group of lichenoid dermatoses.

  10. Design of radial phononic crystal using annular soft material with low-frequency resonant elastic structures

    Science.gov (United States)

    Gao, Nansha; Wu, Jiu Hui; Yu, Lie; Xin, Hang

    2016-10-01

    Using FEM, we theoretically study the vibration properties of radial phononic crystal (RPC) with annular soft material. The band structures, transmission spectra, and displacement fields of eigenmode are given to estimate the starting and cut-off frequency of band gaps. Numerical calculation results show that RPC with annular soft material can yield low-frequency band gaps below 350 Hz. Annular soft material decreases equivalent stiffness of the whole structure effectively, and makes corresponding band gaps move to the lower frequency range. Physical mechanism behind band gaps is the coupling effect between long or traveling wave in plate matrix and the vibrations of corrugations. By changing geometrical dimensions of plate thickness e, the length of silicone rubber h2, and the corrugation width b, we can control the location and width of the first band gap. These research conclusions of RPC structure with annular soft material can potentially be applied to optimize band gaps, generate filters, and design acoustic devices.

  11. Instability of Annular Beam with Finite Thickness in Dielectric-Loaded Cylindrical Waveguide

    OpenAIRE

    Tamura, Shusuke; Yamakawa, Mitsuhisa; Takashima, Yusuke; Ogura, Kazuo

    2008-01-01

    The cherenkov and slow cyclotron instabilities driven by an axially injected electron beam in a cylindrical waveguide are studied using a new version of the self-consistent linear theory considering three-dimensional beam perturbations. There are three kinds of models for beam instability analysis, which are based on a cylindrical solid beam, an infinitesimally thin annular beam, and a finitely thick annular beam. Among these models, the beam shape properly representing the often used actual ...

  12. Non-approximate method for designing annular field of two-mirror concentric system

    Institute of Scientific and Technical Information of China (English)

    Yuanshen Huang; Dongyue Zhu; Baicheng Li; Dawei Zhang; Zhengji Ni; Songlin Zhuang

    2012-01-01

    Annular field aberrations of a three-reflection concentric system, which are composed of two spherical mirrors, are analyzed. An annular field with a high level of aberration correction exists near the position where the principal ray is perpendicular to the object-image plane. Aberrations are determined by the object height and aperture angle. In this letter, the general expression of the system aberration is derived using the geometric method, and the non-approximate design method is proposed to calculate the radii of the annular fields that have minimum aberrations under different aperture angles. The closer to 0.5 (the ratio of the radius of convex mirror to the radius of concave mirror) is, the smaller the system aberration is. The examples analyzed by LABVIEW indicate that the annular field designed by the proposed method has the smallest aberration in a given system.%Annular field aberrations of a three-reflection concentric system,which are composed of two spherical mirrors,are analyzed.An annular field with a high level of aberration correction exists near the position where the principal ray is perpendicular to the object-image plane.Aberrations are determined by the object height and aperture angle.In this letter,the general expression of the system aberration is derived using the geometric method,and the non-approximate design method is proposed to calculate the radii of the annular fields that have minimum aberrations under different aperture angles.The closer to 0.5 (the ratio of the radius of convex mirror to the radius of concave mirror) is,the smaller the system aberration is.The examples analyzed by LABVIEW indicate that the annular field designed by the proposed method has the smallest aberration in a given system.

  13. Predictors of right ventricular function as measured by tricuspid annular plane systolic excursion in heart failure

    DEFF Research Database (Denmark)

    Kjaergaard, Jesper; Iversen, Kasper K; Akkan, Dilek

    2009-01-01

    motion index scores, atrio-ventricular annular plane systolic excursion of the mitral annulus were significantly related to TAPSE. Septal and posterior mitral annular plane systolic excursion (beta = 0.56, p ... in heart failure patients, in particular with reduced septal longitudinal motion. TAPSE is decreased in patients with heart failure of ischemic etiology. However, the absolute reduction in TAPSE is small and seems to be of minor importance in the clinical utilization of TAPSE whether applied as a measure...

  14. Use of a pulsed column contactor as a continuous oxalate precipitation reactor

    Energy Technology Data Exchange (ETDEWEB)

    Borda, Gilles, E-mail: gilles.borda@cea.f [Commissariat a l' Energie Atomique, Nuclear Energy Division, Fuel Cycle Technology Department, BP17171, F 30207 Bagnols sur Ceze Cedex (France); Brackx, Emmanuelle; Boisset, Laurence; Duhamet, Jean [Commissariat a l' Energie Atomique, Nuclear Energy Division, Fuel Cycle Technology Department, BP17171, F 30207 Bagnols sur Ceze Cedex (France); Ode, Denis, E-mail: denis.ode@cea.f [Commissariat a l' Energie Atomique, Nuclear Energy Division, Fuel Cycle Technology Department, BP17171, F 30207 Bagnols sur Ceze Cedex (France)

    2011-03-15

    Research highlights: {yields} A new type of continuous precipitating device was patented by CEA and tested with reaction between a surrogate nitrate cerium(III) or neodymium(III) and oxalate complexing agent. {yields} Precipitate is confined in aqueous phase emulsion in tetrapropylene hydrogen and does not form deposit on the vessel walls. {yields} Measure size of the precipitate ranges from 20 to 40 {mu}m, it meets the process requirements to filter, and the precipitation reaction is complete. {yields} The laboratory design can be extrapolated to an industrial uranium(IV) and minor actinide(III) coprecipitating column. - Abstract: The current objective of coprecipitating uranium, and minor actinides in order to fabricate a new nuclear fuel by direct (co)precipitation for further transmutation, requires to develop specific technology in order to meet the following requirements: nuclear maintenance, criticity, and potentially high flowrates due to global coprecipitation. A new type of device designed and patented by the CEA was then tested in 2007 under inactive conditions and with uranium. The patent is for organic confinement in a pulsed column (PC). Actually, pulsed columns have been working for a long time in a nuclear environment, as they allow high capacity, sub-critical design (annular geometry) and easy high activity maintenance. The precipitation reaction between the oxalate complexing agent and a surrogate nitrate - cerium(III) or neodymium(III) alone, or coprecipitated uranium(IV) and cerium(III) - occurs within an emulsion created in the device by these two phases flowing with a counter-current chemically inert organic phase (for example tetrapropylene hydrogen-TPH) produced by the stirring action of the column pulsator. The precipitate is confined and thus does not form deposits on the vessel walls (which are also water-repellent); it flows downward by gravity and exits the column continuously into a settling tank. The results obtained for precipitation

  15. Design and analysis of 19 pin annular fuel rod cluster for pressure tube type boiling water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Deokule, A.P., E-mail: abhijit.deokule1986@gmail.com [Homi Bhabha National Institute, Trombay 400 085, Mumbai (India); Vishnoi, A.K.; Dasgupta, A.; Umasankari, K.; Chandraker, D.K.; Vijayan, P.K. [Bhabha Atomic Research Centre, Trombay 400 085, Mumbai (India)

    2014-09-15

    Highlights: • Development of 19 pin annular fuel rod cluster. • Reactor physics study of designed annular fuel rod cluster. • Thermal hydraulic study of annular fuel rod cluster. - Abstract: An assessment of 33 pin annular fuel rod cluster has been carried out previously for possible use in a pressure tube type boiling water reactor. Despite the benefits such as negative coolant void reactivity and larger heat transfer area, the 33 pin annular fuel rod cluster is having lower discharge burn up as compared to solid fuel rod cluster when all other parameters are kept the same. The power rating of this design cannot be increased beyond 20% of the corresponding solid fuel rod cluster. The limitation on the power is not due to physics parameters rather it comes from the thermal hydraulics side. In order to increase power rating of the annular fuel cluster, keeping same pressure tube diameter, the pin diameter was increased, achieving larger inside flow area. However, this reduces the number of annular fuel rods. In spite of this, the power of the annular fuel cluster can be increased by 30% compared to the solid fuel rod cluster. This makes the nineteen pin annular fuel rod cluster a suitable option to extract more power without any major changes in the existing design of the fuel. In the present study reactor physics and thermal hydraulic analysis carried out with different annular fuel rod cluster geometry is reported in detail.

  16. Annular structures as intermediates in fibril formation of Alzheimer Abeta17-42.

    Science.gov (United States)

    Zheng, Jie; Jang, Hyunbum; Ma, Buyong; Nussinov, Ruth

    2008-06-05

    We report all-atom molecular dynamics simulations of annular beta-amyloid (17-42) structures, single- and double-layered, in solution. We assess the structural stability and association force of Abeta annular oligomers associated through different interfaces, with a mutated sequence (M35A), and with the oxidation state (M35O). Simulation results show that single-layered annular models display inherent structural instability: one is broken down into linear-like oligomers, and the other collapses. On the other hand, a double-layered annular structure where the two layers interact through their C-termini to form an NC-CN interface (where N and C are the N and C termini, respectively) exhibits high structural stability over the simulation time due to strong hydrophobic interactions and geometrical constraints induced by the closed circular shape. The observed dimensions and molecular weight of the oligomers from atomic force microscopy (AFM) experiments are found to correspond well to our stable double-layered model with the NC-CN interface. Comparison with K3 annular structures derived from the beta 2-microglobulin suggests that the driving force for amyloid formation is sequence specific, strongly dependent on side-chain packing arrangements, structural morphologies, sequence composition, and residue positions. Combined with our previous simulations of linear-like Abeta, K3 peptide, and sup35-derived GNNQQNY peptide, the annular structures provide useful insight into oligomeric structures and driving forces that are critical in amyloid fibril formation.

  17. Depth-targeted transvascular drug delivery by using annular-shaped photomechanical waves

    Science.gov (United States)

    Akiyama, Takuya; Sato, Shunichi; Ashida, Hiroshi; Terakawa, Mitsuhiro

    2011-02-01

    Laser-based drug delivery is attractive for the targeting capability due to high spatial controllability of laser energy. Recently, we found that photomechanical waves (PMWs) can transiently increase the permeability of blood vessels in skin, muscle and brain of rats. In this study, we examined the use of annular-shaped PMWs to increase pressure at target depths due to superposition effect of pressure waves. This can increase the permeability of blood vessels located in the specific depth regions, enabling depth-targeted transvascular drug delivery. Annular PMWs were produced by irradiating a laser-absorbing material with annular-shaped pulsed laser beams that were produced by using an axicon lens. We first examined propagation and pressure characteristics of annular PMWs in tissue phantoms and confirmed an increased pressure at a target depth, which can be controlled by changing laser parameters. We injected Evans blue (EB) into a rat tail vein, and annular PMWs (inner diameter, 3 mm; outer diameter, 5 mm) were applied from the myofascial surface of the anterior tibialis muscle. After perfusion fixation, we observed fluorescence originating from EB in the tissue. We observed intense fluorescence at a target depth region of around 5 mm. These results demonstrate the capability of annular PMWs for depth-targeted transvascular drug delivery.

  18. Triple antibiotic combination therapy may improve but not resolve granuloma annulare.

    Science.gov (United States)

    Simpson, Brenda; Foster, Shannon; Ku, Jennifer H; Simpson, Eric L; Ehst, Benjamin D

    2014-01-01

    Granuloma annulare is a fairly common entity yet lacks reliable treatment options especially when multiple lesions or dissemination exists. A recent case series suggests that a regimen of three oral antibiotics may prove to be an effective treatment. Our objective is to evaluate the efficacy of once monthly triple antibiotic therapy for granuloma annulare. We conducted an open-label prospective study of subjects with at least five lesions of granuloma annulare who received once monthly rifampin, ofloxacin, and minocycline for 6 months. Improvement was measured with a novel objective Granuloma Annulare Severity Index (GASI) scoring system. Twenty-one subjects enrolled. Ten subjects (48%) achieved at least a 50% reduction in their GASI, including three subjects (14%) who reached 75% improvement and one subject (5%) whose skin cleared. Six subjects (29%) had no change or worsening of their granuloma annulare. Median GASI scores decreased significantly by 15 points (p antibiotic use may improve but not clear granuloma annulare over 6 months. Randomized trials may be warranted to further assess this therapy.

  19. Cultivation of Spirulina maxima in an annular photochemical reactor

    Energy Technology Data Exchange (ETDEWEB)

    Leduy, A.; Therien, N.

    1979-08-01

    An 8-L annular photochemical reactor has been designed and built for the cultivation of micro- or semi-microalgae at the laboratory scale. It may be operated in batch or continuous mode and is controlled for pH, temperature, gas mixture ratio (CO/sub 2/ and air), flow rate, light intensity and also illumination type (daylight or plant growth light) and mode (continuous or intermittent). It behaves as a perfect mixed reactor for all concentrations of algal cells. The reactor was used for the cultivation of the blue-green alga Spirulina maxima in a synthetic medium in both batch and continuous operations. At the dilution rate of 0.24 day/sup -1/, the optimal productivity was 0.91 g/L-day for biomass or 0.55 g/L-day for protein. This is equivalent to 14.5 g/m/sup 2/-day for biomass or 8.7 g/m/sup 2/-day for protein. The optimal productivity as well as the chemical composition of the algal biomass were comparable to results obtained from pilot plant studies and reported in the current literature.

  20. Annular beam shaping system for advanced 3D laser brazing

    Science.gov (United States)

    Pütsch, Oliver; Stollenwerk, Jochen; Kogel-Hollacher, Markus; Traub, Martin

    2012-10-01

    As laser brazing benefits from advantages such as smooth joints and small heat-affected zones, it has become established as a joining technology that is widely used in the automotive industry. With the processing of complex-shaped geometries, recent developed brazing heads suffer, however, from the need for continuous reorientation of the optical system and/or limited accessibility due to lateral wire feeding. This motivates the development of a laser brazing head with coaxial wire feeding and enhanced functionality. An optical system is designed that allows to generate an annular intensity distribution in the working zone. The utilization of complex optical components avoids obscuration of the optical path by the wire feeding. The new design overcomes the disadvantages of the state-of-the-art brazing heads with lateral wire feeding and benefits from the independence of direction while processing complex geometries. To increase the robustness of the brazing process, the beam path also includes a seam tracking system, leading to a more challenging design of the whole optical train. This paper mainly discusses the concept and the optical design of the coaxial brazing head, and also presents the results obtained with a prototype and selected application results.

  1. Stability of three-layered core-annular flow

    Science.gov (United States)

    Pillai, Dipin; Pushpavanam, Subramaniam; Sundararajan, T.

    2016-11-01

    Stability of a three-layered core-annular flow is analyzed using the method of modal linear stability analysis. A temporal analysis shows that the flow becomes unstable to two modes of instability when inertial effects are negligible. An energy budget analysis reveals that these two modes correspond to capillary instability associated with each fluid-fluid interface. With an increase in Reynolds number, the system exhibits additional Reynolds stress modes of instabilities. These modes correspond to the Tollmien-Schlichting type of waves associated with high Reynolds number shear flows, and are considered precursor to transition to turbulence. An investigation of the parameter space reveals that the system may simultaneously show up to 5 distinct modes of instability, viz., the two capillary modes at each interface and three Reynolds stress modes in the bulk of each phase. In addition, a spatio-temporal analysis shows that the Reynolds stress modes are always convectively unstable whereas the capillary modes may undergo a transition from convective to absolute instability with decrease in Weber number. To obtain encapsulated droplets in experiments, the operating parameters must be chosen such that the system lies in the regime of convective instability. MHRD-Govt of India, NSF 0968313.

  2. Linear Unsteady Aerodynamic Forces on Vibrating Annular Cascade Blades

    Institute of Scientific and Technical Information of China (English)

    Taketo Nagasaki; Nobuhiko Yamasaki

    2003-01-01

    The paper presents the formulation to compute numerically the unsteady aerodynamic forces on the vibrating annular cascade blades. The formulation is based on the finite volume method. By applying the TVD scheme to the linear unsteady calculations, the precise calculation of the peak of unsteady aerodynamic forces at the shock wave location like the delta function singularity becomes possible without empirical constants. As a further feature of the present paper, results of the present numerical calculation are compared with those of the double lineaxization theory (DLT), which assumes small unsteady and steady disturbances but the unsteady disturbances are much smaller than the steady disturbances. Since DLT requires fax less computational resources than the present numerical calculation, the validation of DLT is quite important from the engineering point of view. Under the conditions of small steady disturbances, a good agreement between these two results is observed, so that the two codes axe cross-validated.The comparison also reveals the limitation on the applicability of DLT.

  3. Imbalanced superfluid state in an annular disk.

    Science.gov (United States)

    Ye, Fei; Chen, Yan; Wang, Z D; Zhang, F C

    2009-09-02

    The imbalanced superfluid state of spin- 1/2 fermions with s-wave pairing is numerically studied by solving the Bogoliubov-de Gennes equation at zero temperature in an annular disk geometry with narrow radial width. Two distinct types of systems are considered. The first case may be relevant to heavy fermion superconductors, where magnetic field causes spin imbalance via Zeeman interaction and the system is studied in a grand canonical ensemble. As the magnetic field increases, the system is transformed from the uniform superfluid state to the Fulde-Ferrell-Larkin-Ovchinnikov state, and finally to the spin polarized normal state. The second case may be relevant to cold fermionic systems, where the number of fermions of each species is fixed as in a canonical ensemble. In this case, the ground state depends on the pairing strength. For weak pairing, the order parameter exhibits a periodic domain wall lattice pattern with a localized spin distribution at low spin imbalance, and a sinusoidally modulated pattern with extended spin distribution at high spin imbalance. For strong pairing, the phase separation between the superfluid state and polarized normal state is found to be preferable, while the increase of spin imbalance simply changes the ratio between them.

  4. Adipophilin expression in necrobiosis lipoidica, granuloma annulare, and sarcoidosis.

    Science.gov (United States)

    Schulman, Joshua M; LeBoit, Philip E

    2015-03-01

    Necrobiosis lipoidica (NL), granuloma annulare (GA), and sarcoidosis usually are distinguished by clinical presentation and routine microscopy, but their distinction can sometimes be challenging. Historically, a clue to diagnosing NL or GA has been the identification of lipid droplets in the areas of altered collagen, but such studies have required fresh frozen tissue, making them impractical. Here, we present the first report of immunohistochemical staining to detect adipophilin, a membrane protein in lipid droplets, in NL (n = 12), GA (n = 19), sarcoidosis (n = 12), and, as a control for nonspecific tissue damage, nongranulomatous cutaneous necrosis (n = 13). Four patterns of labeling were identified: (1) extracellular, within zones of altered collagen; (2) both intracellular and extracellular, after the distribution of palisaded or scattered histiocytes; (3) intracellular, within clustered histiocytes; and (4) periadnexal. All cases of NL demonstrated pattern 1; nearly all cases of GA (18/19) demonstrated pattern 2; most sarcoidosis (10/12) demonstrated pattern 3; and nongranulomatous necrosis demonstrated either pattern 4 (6/13) or did not stain (6/13), confirming that the antibody to adipophilin did not adhere nonspecifically to the damaged tissue. An additional set of 3 biopsies with overlapping or partially sampled features of NL, GA, and/or sarcoidosis subsequently confirmed the potential utility of adipophilin staining in diagnostically challenging cases. We conclude that the pattern of adipophilin expression is a useful adjunct in the evaluation of granulomatous dermatitis.

  5. HAMLET forms annular oligomers when deposited with phospholipid monolayers.

    Science.gov (United States)

    Baumann, Anne; Gjerde, Anja Underhaug; Ying, Ming; Svanborg, Catharina; Holmsen, Holm; Glomm, Wilhelm R; Martinez, Aurora; Halskau, Oyvind

    2012-04-20

    Recently, the anticancer activity of human α-lactalbumin made lethal to tumor cells (HAMLET) has been linked to its increased membrane affinity in vitro, at neutral pH, and ability to cause leakage relative to the inactive native bovine α-lactalbumin (BLA) protein. In this study, atomic force microscopy resolved membrane distortions and annular oligomers (AOs) produced by HAMLET when deposited at neutral pH on mica together with a negatively charged lipid monolayer. BLA, BAMLET (HAMLET's bovine counterpart) and membrane-binding Peptide C, corresponding to BLA residues 75-100, also form AO-like structures under these conditions but at higher subphase concentrations than HAMLET. The N-terminal Peptide A, which binds to membranes at acidic but not at neutral pH, did not form AOs. This suggests a correlation between the capacity of the proteins/peptides to integrate into the membrane at neutral pH-as observed by liposome content leakage and circular dichroism experiments-and the formation of AOs, albeit at higher concentrations. Formation of AOs, which might be important to HAMLET's tumor toxic action, appears related to the increased tendency of the protein to populate intermediately folded states compared to the native protein, the formation of which is promoted by, but not uniquely dependent on, the oleic acid molecules associated with HAMLET.

  6. Friction factor of annular Poiseuille flow in a transitional regime

    Directory of Open Access Journals (Sweden)

    Takahiro Ishida

    2016-12-01

    Full Text Available Annular Poiseuille flows in a transitional regime were investigated by direct numerical simulations with an emphasis on turbulent statistics including the friction factor that are affected by the presence of large-scale transitional structures. Five different radius ratios in the range of 0.1–0.8 and several friction Reynolds numbers in the range of 48–150 were analyzed to consider various flow states accompanied by characteristic transitional structures. Three characteristic structures, namely, turbulent–laminar coexistence referred to as “(straight puff,”“helical puff,” and “helical turbulence” were observed. The selection of the structures depends on both the radius ratio and the Reynolds number. The findings indicated that despite the transitional state with a turbulent–laminar coexistence, the helical turbulence resulted in a friction factor that was as high as the fully turbulent value. In contrast, with respect to the occurrence of streamwise-finite transitional structures, such as straight/helical puffs, the friction factor decreased in a stepwise manner toward a laminar level. The turbulent statistics revealed asymmetric distributions with respect to the wall-normal direction wherein the profiles and magnitudes were significantly influenced by the occurrence of transitional structures.

  7. Numerical Study of Transition of an Annular Lift Fan Aircraft

    Directory of Open Access Journals (Sweden)

    Yun Jiang

    2016-09-01

    Full Text Available The present study aimed at studying the transition of annular lift fan aircraft through computational fluid dynamics (CFD simulations. The oscillations of lift and drag, the optimization for the figure of merit, and the characteristics of drag, yawing, rolling and pitching moments in transition are studied. The results show that a two-stage upper and lower fan lift system can generate oscillations of lift and drag in transition, while a single-stage inner and outer fan lift system can eliminate the oscillations. The characteristics of momentum drag of the single-stage fans in transition are similar to that of the two-stage fans, but with the peak of drag lowered from 0.63 to 0.4 of the aircraft weight. The strategy to start transition from a negative angle of attack −21° further reduces the peak of drag to 0.29 of the weight. The strategy also reduces the peak of pitching torque, which needs upward extra thrusts of 0.39 of the weight to eliminate. The peak of rolling moment in transition needs differential upward thrusts of 0.04 of the weight to eliminate. The requirements for extra thrusts in transition lead to a total thrust–weight ratio of 0.7, which makes the aircraft more efficient for high speed cruise flight (higher than 0.7 Ma.

  8. Modeling and analysis of thermoacoustic instabilities in an annular combustor

    Science.gov (United States)

    Murthy, Sandeep; Sayadi, Taraneh; Le Chenadec, Vincent; Schmid, Peter

    2015-11-01

    A simplified model is introduced to study thermo-acoustic instabilities in axisymmetric combustion chambers. Such instabilities can be triggered when correlations between heat-release and pressure oscillations exist, leading to undesirable effects. Gas turbine designs typically consist of a periodic assembly of N identical units; as evidenced by documented studies, the coupling across sectors may give rise to unstable modes, which are the highlight of this study. In the proposed model, the governing equations are linearized in the acoustic limit, with each burner modeled as a one-dimensional system, featuring acoustic damping and a compact heat source. The coupling between the burners is accounted for by solving the two-dimensional wave equation over an annular region, perpendicular to the burners, representing the chamber's geometry. The discretization of these equations results in a set of coupled delay-differential equations, that depends on a finite set of parameters. The system's periodicity is leveraged using a recently developed root-of-unity formalism (Schmid et al., 2015). This results in a linear system, which is then subjected to modal and non-modal analysis to explore the influence of the coupled behavior of the burners on the system's stability and receptivity.

  9. Reactor pulse repeatability studies at the annular core research reactor

    Energy Technology Data Exchange (ETDEWEB)

    DePriest, K.R. [Applied Nuclear Technologies, Sandia National Laboratories, Mail Stop 1146, Post Office Box 5800, Albuquerque, NM 87185-1146 (United States); Trinh, T.Q. [Nuclear Facility Operations, Sandia National Laboratories, Mail Stop 0614, Post Office Box 5800, Albuquerque, NM 87185-1146 (United States); Luker, S. M. [Applied Nuclear Technologies, Sandia National Laboratories, Mail Stop 1146, Post Office Box 5800, Albuquerque, NM 87185-1146 (United States)

    2011-07-01

    The Annular Core Research Reactor (ACRR) at Sandia National Laboratories is a water-moderated pool-type reactor designed for testing many types of objects in the pulse and steady-state mode of operations. Personnel at Sandia began working to improve the repeatability of pulse operations for experimenters in the facility. The ACRR has a unique UO{sub 2}-BeO fuel that makes the task of producing repeatable pulses difficult with the current operating procedure. The ACRR produces a significant quantity of photoneutrons through the {sup 9}Be({gamma}, n){sup 8}Be reaction in the fuel elements. The photoneutrons are the result of the gammas produced during fission and in fission product decay, so their production is very much dependent on the reactor power history and changes throughout the day/week of experiments in the facility. Because the photoneutrons interfere with the delayed-critical measurements required for accurate pulse reactivity prediction, a new operating procedure was created. The photoneutron effects at delayed critical are minimized when using the modified procedure. In addition, the pulse element removal time is standardized for all pulse operations with the modified procedure, and this produces less variation in reactivity removal times. (authors)

  10. Measurement of large aspheric surfaces by annular subaperture stitching interferometry

    Institute of Scientific and Technical Information of China (English)

    Xiaokun Wang; Lihui Wang; Longhai Yin; Binzhi Zhang; Di Fan; Xuejun Zhang

    2007-01-01

    A new method for testing aspheric surfaces by annular subaperture stitching interferometry is introduced.It can test large-aperture and large-relative-aperture aspheric surfaces at high resolution, low cost, and high efficiency without auxiliary null optics. The basic principle of the method is described, the synthetical optimization stitching model and effective algorithm are established based on simultaneous least-square fitting. A hyperboloid with an aperture of 350 mm is tested by this method. The obtained peak-to-valley (PV) and root-mean-square (RMS) values of the surface error after stitching are 0.433λ and 0.052λ (λis 632.8 nm), respectively. The reconstructed surface map is coincide with the entire surface map from null test, and the difference of PV and RMS errors between them are 0.031λ and 0.005λ, respectively.This stitching model provides another quantitive method for testing large aspheric surfaces besides null compensation.

  11. An Unusual Presentation of Annular Pancreas: A Case Report

    Directory of Open Access Journals (Sweden)

    Saleheh Ala

    2015-01-01

    Full Text Available Abstract Annular pancreas (AP is a rare congenital malformation resulting from failure of pancreas ventral anlage rotation with the duodenum. This leads to a ring of pancreatic tissue that envelops the duodenum. Clinical manifestations of AP most commonly develop in infancy or early childhood but can present at any age. The diagnosis of AP, usually suggested by an upper GI series or abdominal CT scan, but surgery is considered the gold standard diagnostic method. Surgical bypass of the annulus in all patients with symptomatic AP is recommended. We report a one year old girl who presented with intermittent, non projectile, non bilious vomiting that occurred 1h to 2h after feeding since neonatal period. Upper GI contrast study demonstrates, a dilated duodenal bulb associated with narrowing of post bulbar area. The patient underwent surgical correction of the obstruction. A bypass of the ectopic pancreas tissue was performed by duodenoduodenostomy. Considering the rarity of this congenital abnormality, presenting with chronic partial duodenal obstruction, and its successful correction by surgical means have prompted us to report the case.

  12. Influences of phase shift on superresolution performances of annular filters

    Institute of Scientific and Technical Information of China (English)

    Liu Xi-Min; Liu Li-Ren; Bai Li-Hua

    2006-01-01

    This paper investigates the influences of phase shift on superresolution performances of annular filters.Firstly,it investigates the influence of phase shift on axial superresolution.It proves theoretically that axial superresolution can not be obtained by two-zone phase filter with phase shift π.and it gets the phase shift with which axial superresolution can be brought by two-zone phase filter.Secondly,it studies the influence of phase shift on transverse superresolution.It finds that the three-zone phase filter with arbitrary phase shift has an almost equal optimal transverse gain to that of commonly used three-zone phase filter,but can produce a much higher axial superresolution gain.Thirdly,it investigates the influence of phase shift on three-dimensional superresolution.Three-dimensional superresolution capability and design margin of three-zone complex filter with arbitrary phase shift are obtained,which presents the theoretical basis for three-dimensional superresolution design. Finally,it investigates the influence of phase shift on focal shift.To obtain desired focal shifts,it designs a series of three-zone phase filters with different phase shifts.A spatial light modulator (SLM) is used to implement the designed filters.By regulating the voltage imposed on the SLM,an accurate focal shift control iS obtained.

  13. Characterization of Novel Calorimeters in the Annular Core Research Reactor *

    Directory of Open Access Journals (Sweden)

    Hehr Brian D.

    2016-01-01

    Full Text Available A series of pulsed irradiation experiments have been performed in the central cavity of Sandia National Laboratories' Annular Core Research Reactor (ACRR to characterize the responses of a set of elemental calorimeter materials including Si, Zr, Sn, Ta, W, and Bi. Of particular interest was the perturbing effect of the calorimeter itself on the ambient radiation field – a potential concern in dosimetry applications. By placing the calorimeter package into a neutron-thermalizing lead/polyethylene (LP bucket and irradiating both with and without a cadmium wrapper, it was demonstrated that prompt capture gammas generated inside the calorimeters can be a significant contributor to the measured dose in the active disc region. An MCNP model of the experimental setup was shown to replicate measured dose responses to within 10%. The internal (n,γ contribution was found to constitute as much as 50% of the response inside the LP bucket and up to 20% inside the nominal (unmodified cavity environment, with Ta and W exhibiting the largest enhancement due to their sizable (n,γ cross sections. Capture reactions in non-disc components of the calorimeter were estimated to be responsible for up to a few percent of the measured response.

  14. Flow Pressure Loss through Straight Annular Corrugated Pipes

    Science.gov (United States)

    Sargent, Joseph R.; Kirk, Daniel R.; Marsell, Brandon; Roth, Jacob; Schallhorn, Paul A.; Pitchford, Brian; Weber, Chris; Bulk, Timothy

    2016-01-01

    Pressure loss through annular corrugated pipes, using fully developed gaseous nitrogen representing purge pipes in spacecraft fairings, was studied to gain insight into a friction factor coefficient for these pipes. Twelve pipes were tested: four Annuflex, four Masterflex and two Titeflex with ¼”, 3/8”, ½” and ¾” inner diameters. Experimental set-up was validated using smooth-pipe and showed good agreement to the Moody diagram. Nitrogen flow rates between 0-200 standard cubic feet per hour were used, producing approximate Reynolds numbers from 300-23,000. Corrugation depth varied from 0.248 = E/D = 0.349 and relative corrugation pitch of 0.192 = P/D = 0.483. Differential pressure per unit length was measured and calculated using 8-9 equidistant pressure taps. A detailed experimental uncertainty analysis, including correlated bias error terms, is presented. Results show larger differential pressure losses than smooth-pipes with similar inner diameters resulting in larger friction factor coefficients.

  15. Sedimentation of a suspension in a centrifugal field.

    Science.gov (United States)

    Lueptow, R M; Hübler, W

    1991-11-01

    To model centrifugal sedimentation of biological suspensions, the time history of sedimentation of particles in a centrifugal field was considered for two geometries: a tube and a cylindrical container. The Kynch theory for batch gravitational settling in Cartesian coordinates based on mass conservation was extended to include a centrifugal sedimentation force, cylindrical coordinates, and the Hawksley-Vand hindered settling model. The resulting quasi-linear partial differential equation was solved by the method of characteristics. The combination of radial dependence of the sedimentation force and cylindrical geometry in the centrifugal case results in several differences in the time-position history diagram of the sedimentation process compared to the gravitational case. First, instead of a region of uniform concentration equal to the initial concentration, a region of concentration that is continuously decreasing with time results. Second, in the region of particle accumulation, curved constant concentration contours result instead of straight lines. Finally, a secondary shock that is dependent upon the initial concentration and the radius ratio of the rotating vessel appears in the centrifugal case. The time history of the concentration for a particle suspension with an initial concentration typical of blood is presented.

  16. Exosome enrichment of human serum using multiple cycles of centrifugation.

    Science.gov (United States)

    Kim, Jeongkwon; Tan, Zhijing; Lubman, David M

    2015-09-01

    In this work, we compared the use of repeated cycles of centrifugation at conventional speeds for enrichment of exosomes from human serum compared to the use of ultracentrifugation (UC). After removal of cells and cell debris, a speed of 110 000 × g or 40 000 × g was used for the UC or centrifugation enrichment process, respectively. The enriched exosomes were analyzed using the bicinchoninic acid assay, 1D gel separation, transmission electron microscopy, Western blotting, and high-resolution LC-MS/MS analysis. It was found that a five-cycle repetition of UC or centrifugation is necessary for successful removal of nonexosomal proteins in the enrichment of exosomes from human serum. More significantly, 5× centrifugation enrichment was found to provide similar or better performance than 5× UC enrichment in terms of enriched exosome protein amount, Western blot band intensity for detection of CD-63, and numbers of identified exosome-related proteins and cluster of differentiation (CD) proteins. A total of 478 proteins were identified in the LC-MS/MS analyses of exosome proteins obtained from 5× UCs and 5× centrifugations including many important CD membrane proteins. The presence of previously reported exosome-related proteins including key exosome protein markers demonstrates the utility of this method for analysis of proteins in human serum.

  17. Experience with the Sarns centrifugal pump in postcardiotomy ventricular failure.

    Science.gov (United States)

    Curtis, J J; Walls, J T; Schmaltz, R; Boley, T M; Nawarawong, W; Landreneau, R J

    1992-09-01

    The reported clinical use of the Sarns centrifugal pump (Sarns, Inc./3M, Ann Arbor, Mich.) as a cardiac assist device for postcardiotomy ventricular failure is limited. During a 25-month period ending November 1988, we used 40 Sarns centrifugal pumps as univentricular or biventricular cardiac assist devices in 27 patients who could not be weaned from cardiopulmonary bypass despite maximal pharmacologic and intraaortic balloon support. Eighteen men and nine women with a mean age of 60.4 years (28 to 83) required assistance. Left ventricular assist alone was used in 12 patients, right ventricular assist in 2, and biventricular assist in 13. The duration of assist ranged from 2 to 434 hours (median 45). Centrifugal assist was successful in weaning 100% of the patients. Ten of 27 patients (37%) improved hemodynamically, allowing removal of the device(s), and 5 of 27 (18.5%) survived hospitalization. Survival of patients requiring left ventricular assist only was 33.3% (4/12). Complications were common and included renal failure, hemorrhage, coagulopathy, ventricular arrhythmias, sepsis, cerebrovascular accident, and wound infection. During 3560 centrifugal pump hours, no pump thrombosis was observed. The Sarns centrifugal pump is an effective assist device when used to salvage patients who otherwise cannot be weaned from cardiopulmonary bypass. Statistical analysis of preoperative patient characteristics, operative risk factors, and postoperative complications failed to predict which patients would be weaned from cardiac assist or which would survive.

  18. Shifts in the microbial community, nitrifiers and denitrifiers in the biofilm in a full-scale rotating biological contactor.

    Science.gov (United States)

    Peng, Xingxing; Guo, Feng; Ju, Feng; Zhang, Tong

    2014-07-15

    The objective of this study was to investigate the microbial community shifts, especially nitrifiers and denitrifiers, in the biofilm of two rotating biological contactor (RBC) trains with different running times along the plug flowpath. The microbial consortia were profiled using multiple approaches, including 454 high-throughput sequencing of the V3-V4 region of 16S rRNA gene, clone libraries, and quantitative polymerase chain reaction (qPCR). The results demonstrated that (1) the overall microbial community at different locations had distinct patterns, that is, there were similar microbial communities at the beginnings of the two RBC trains and completely different populations at the ends of the two RBC trains; (2) nitrifiers, including ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB, Nitrosomonas) and nitrite-oxidizing bacteria (NOB, Nitrospira), increased in relative abundance in the biofilm along the flowpath, whereas denitrifiers (Rhodanobacter, Paracoccus, Thauera, and Azoarcus) markedly decreased; (3) the AOA were subdominant to the AOB in all sampled sections; and (4) strong ecological associations were shown among different bacteria. Overall, the results of this study provided more comprehensive information regarding the biofilm community composition and assemblies in full-scale RBCs.

  19. Effect of Flow Rate and Disc Area Increment on the Efficiency of Rotating Biological Contactor for Treating Greywater

    Directory of Open Access Journals (Sweden)

    Ashfaq Ahmed Pathan

    2015-04-01

    Full Text Available The performance of greywater treatment through RBC (Rotating Biological Contactor is related to many factors including rotational speed of disc, surface area of the media, thickness of biological film; quality and flow rate of influent. The plastic media provides surface for biological slime. The slime is rotated alternatively into the settled wastewater and then into atmosphere to provide aerobic conditions for the microorganisms. In this study the performance of RBC is investigated at different flow rates and disk areas of media by introducing additional discs on the shaft of RBC. Initially efficiency of the RBC was observed on six flow rates at the disc area of 9.78m2. Furthermore optimized three flow rates were used to augment the disk area. The efficiency of RBC system was improved significantly at disk area of 11.76m2 and flow rate of 20 L/h. Under these conditions the removal of BOD5 (Biochemical Oxygen Demand COD (Chemical Oxygen Demand and TSS (Total Suspended Solid was observed 83, 57 and 90% respectively

  20. Biodegradation and detoxification potential of rotating biological contactor (RBC) with Irpex lacteus for remediation of dye-containing wastewater.

    Science.gov (United States)

    Malachova, Katerina; Rybkova, Zuzana; Sezimova, Hana; Cerven, Jiri; Novotny, Cenek

    2013-12-01

    Use of fungal organisms in rotating biological contactors (RBC) for bioremediation of liquid industrial wastes has so far been limited in spite of their significant biodegradation potential. The purpose was to investigate the power of RBC using Irpex lacteus for decolorization and detoxification of industrial dyes and dyeing textile liquors. Recalcitrant dye Methylene Blue (150 mg L(-1)) was decolorized within 70 days, its mutagenicity removed, and the biological toxicity decreased more than 10-fold. I. lacteus biofilm in the RBC completely decolorized within 26 and 47 days dyeing liquors containing disperse or reactive dyes adjusted to pH4.5 and 5-fold diluted with the growth medium, respectively. Their respective biological toxicity values were reduced 10- to 10(4)-fold in dependence of the test used. A battery of toxicity tests comprising Vibrio fisheri, Lemna minor and Sinapis alba was efficient to monitor the toxicity of textile dyes and wastewaters. Strong decolorization and detoxification power of RBC using I. lacteus biofilms was demonstrated.

  1. Centrifuge modelling of drained lateral pile - soil response

    DEFF Research Database (Denmark)

    Klinkvort, Rasmus Tofte

    of rigid piles. The tests have been performed in homogeneously dense dry or saturated Fontainebleau sand in order to mimic simplified drained offshore soil conditions. Approximately half of the tests have been carried out to investigate the centrifuge procedure in order to create a methodology of testing...... for monopiles today. Therefore it appears that the methodology for monopiles lacks scientific justification and a better understanding of rigid piles is needed. More than 70 centrifuge tests on laterally loaded rigid model piles have been carried out in connection with this thesis to get a better understanding...... that enables the transformation of result from tests in model scale to prototype scale. The grain size to pile diameter ratio, the non-linear stress distribution and the pile installation was identified from this investigation as important parameters in reliable scaling of centrifuge results. The remaining...

  2. Investigation of Surge Behavior in a Micro Centrifugal Compressor

    Institute of Scientific and Technical Information of China (English)

    Shimpei MIZUKI; Yuichiro ASAGA; Yushi ONO; Hoshio TSUJITA

    2006-01-01

    This paper reports the experimental and theoretical study of the surge occurred in prototyping an ultra micro centrifugal compressor. As the first step, the 10 times size model of an ultra micro centrifugal compressor having the 40 mm outer diameter was designed and manufactured. The detailed experimental investigations for the transient behavior of surge with several different values of B parameter were carried out. The experimental results during the surge were compared with those obtained by the non-linear lumped parameter theory in order to validate the effectiveness of the theoretical surge model for the micro centrifugal compressor. As a result, the quite different behavior of the surge appeared for the different values of B both in the experiment and in the analysis.

  3. Passively Shunted Piezoelectric Damping of Centrifugally-Loaded Plates

    Science.gov (United States)

    Duffy, Kirsten P.; Provenza, Andrew J.; Trudell, Jeffrey J.; Min, James B.

    2009-01-01

    Researchers at NASA Glenn Research Center have been investigating shunted piezoelectric circuits as potential damping treatments for turbomachinery rotor blades. This effort seeks to determine the effects of centrifugal loading on passively-shunted piezoelectric - damped plates. Passive shunt circuit parameters are optimized for the plate's third bending mode. Tests are performed both non-spinning and in the Dynamic Spin Facility to verify the analysis, and to determine the effectiveness of the damping under centrifugal loading. Results show that a resistive shunt circuit will reduce resonant vibration for this configuration. However, a tuned shunt circuit will be required to achieve the desired damping level. The analysis and testing address several issues with passive shunt circuit implementation in a rotating system, including piezoelectric material integrity under centrifugal loading, shunt circuit implementation, and tip mode damping.

  4. Centrifuge modeling of shallow foundation on soft soil

    Energy Technology Data Exchange (ETDEWEB)

    Leung, P.K.; Ku, H.Y.; Pane, V.; Schiffman, R.L.

    1984-05-01

    A series of centrifuge model tests was performed to study the behavior of shallow foundations on soft normally consolidated clay. The model tests included testing of foundation models with one-dimensional, plane strain, and axially symmetric geometries. The nonlinear consolidation properties of the soil were determined using specially developed laboratory testing techniques. The centrifuge test data were then compared with conventional and finite strain theories for consolidation assessment, as well as a limit analysis solution for foundation stability considerations. It is found that centrifuge testing coupled with careful laboratory testing provides a useful tool to validate analytical procedures. It has demonstrated that the finite strain theory and the limit analysis solution are valid procedures for the determination of consolidation settlement and foundation penetration of shallow foundations on soft soil, respectively.

  5. Studies on preparation of aceclofenac pellets by centrifugal granulator

    Directory of Open Access Journals (Sweden)

    Zibin GAO

    Full Text Available To prepare aceclofenac pellets by centrifugal granulation. Using 90~100 g of starch pellets as the core pellets,100 g of aceclofenac mixed with 50 g of microcrystalline cellulose(MCC and 4 g talc, methyl cellulose (HPMC as binder,the aceclofenac pellets were prepared by centrifugal granulation .And evaluate the quality of the pellets. The aceclofenac pellets had high yield and less losses,the pellets had a partical size of 0.70~0.88 mm(18~24 mesh)and had uniform particle size .the moisture ,drug content and dissolution meet the requirement . Aceclofenac pellets were prepared by the process of centrifugal granulation .The preparation prescription and process parameters were optimized by single factor method .and the pellets meet the standard requirements.

  6. Centrifuge modelling of a laterally cyclic loaded pile

    DEFF Research Database (Denmark)

    Klinkvort, Rasmus Tofte; Leth, Caspar Thrane; Hededal, Ole

    2010-01-01

    A total number of 9 static and 6 cyclic centrifuge tests on laterally loaded piles in very dense, dry sand was erformed. The prototype dimensions of the piles were 1 meter in diameter and penetration depths varying from 6 to 10 meters. The static tests were used to investigate the initial subgrade...... reaction modulus and as a reference for cyclic tests. For the cyclic tests the accumulation of deflections and the change in secant stiffness of the soil from repetitive loading were investigated. From all the tests carried out accumulations of deflections were seen. rom the centrifuge tests it was seen...

  7. Secondary Containment Design for a High Speed Centrifuge

    Energy Technology Data Exchange (ETDEWEB)

    Snyder, K.W.

    1999-03-01

    Secondary containment for high speed rotating machinery, such as a centrifuge, is extremely important for operating personnel safety. Containment techniques can be very costly, ungainly and time consuming to construct. A novel containment concept is introduced which is fabricated out of modular sections of polycarbonate glazed into a Unistrut metal frame. A containment study for a high speed centrifuge is performed which includes the development of parameters for secondary containment design. The Unistrut/polycarbonate shield framing concept is presented including design details and proof testing procedures. The economical fabrication and modularity of the design indicates a usefulness for this shielding system in a wide variety of containment scenarios.

  8. Aspiration spiral-flow type centrifugal flotation machine

    Institute of Scientific and Technical Information of China (English)

    陈文义

    2002-01-01

    Aspiration spiral flow type centrifugal flotation machine takes full advantage of centrifugal force field and gravitational field, and strengthens flotation of coal slurry. As a new-type flotation machine of high efficiency, its key component is bubble generator. Which completes the process of ore pulp inflation and liberalization. The design, parameters and working principle of bubble generator provide the design of the same device in similar equipment with reference. The result of industrial operation shows that this machine is of such features as small occupational area, greater concentration ratio, high processing capacity, high efficiency and lower investment etc.

  9. Deep eutectic solvents in countercurrent and centrifugal partition chromatography.

    Science.gov (United States)

    Roehrer, Simon; Bezold, Franziska; García, Eva Marra; Minceva, Mirjana

    2016-02-19

    Deep eutectic solvents (DESs) were evaluated as solvents in centrifugal partition chromatography, a liquid-liquid chromatography separation technology. To this end, the partition coefficients of ten natural compounds of different hydrophobicity were determined in non-aqueous biphasic systems containing DES. The influence of the composition of DESs and the presence of water in the biphasic system on the partition coefficient were also examined. In addition, several process relevant physical properties of the biphasic system, such as the density and viscosity of the phases, were measured. A mixture of three to four hydrophobic compounds was successfully separated in a centrifugal partition extractor using a heptane/ethanol/DES biphasic system.

  10. Centripetal Acceleration and Centrifugal Force in General Relativity

    Science.gov (United States)

    Bini, D.; de Felice, F.; Jantzen, R. T.

    2003-05-01

    In nonrelativistic mechanics noninertial observers studying accelerated test particle motion experience a centripetal acceleration which, once interpreted as a centrifugal force acting on the particle, allows writing the particle's equation of motion in a Newtonian form, simply by adding the inertial force contribution to that of the external forces in the acceleration-equals-force equation. In general relativity centripetal and centrifugal acceleration generalizing the classical concepts must be properly (geometrically) defined. This requires a relative Frenet-Serret frame approach based on a family of test observers.

  11. Model Based Fault Detection in a Centrifugal Pump Application

    DEFF Research Database (Denmark)

    Kallesøe, Carsten; Cocquempot, Vincent; Izadi-Zamanabadi, Roozbeh

    2006-01-01

    A model based approach for fault detection in a centrifugal pump, driven by an induction motor, is proposed in this paper. The fault detection algorithm is derived using a combination of structural analysis, observer design and Analytical Redundancy Relation (ARR) design. Structural consideration...... is capable of detecting four different faults in the mechanical and hydraulic parts of the pump.......A model based approach for fault detection in a centrifugal pump, driven by an induction motor, is proposed in this paper. The fault detection algorithm is derived using a combination of structural analysis, observer design and Analytical Redundancy Relation (ARR) design. Structural considerations...

  12. Electromagnetic Transformation of DF4D Diesel Locomotive Electric Air Contactor%DF4D型内燃机车电空接触器电磁化改造

    Institute of Scientific and Technical Information of China (English)

    徐冬明; 朱琳; 欧阳爱莲

    2015-01-01

    Aiming at the problem of high failure rate and poor reliability of the electric air contactor of the DF4D die⁃sel locomotive,the improvement scheme of the electro pneumatic contactor is put forward in this paper.%本文针对DF4D型内燃机车主电路电空接触器故障率高、可靠性差等问题,提出电空接触器电磁化改进方案。

  13. Measurement of mass transfer coefficients in a mechanically agitated, nondispersing contactor operating with a molten mixture of LiF--BeF/sub 2/--ThF/sub 4/ and molten bismuth

    Energy Technology Data Exchange (ETDEWEB)

    Brown, C.H. Jr.; Hightower, J.R. Jr.; Klein, J.A.

    1976-11-01

    A mechanically agitated, nondispersing contactor in which molten fluoride salt and molten bismuth phases were contacted has been built and operated. The mass transfer performance of the contactor was evaluated over a range of agitator speeds under conditions in which the major resistance to mass transfer was in the salt phase. The measured mass transfer rates were compared with rates predicted by literature correlations. The equipment necessary to contain the salt and bismuth at approximately 600/sup 0/C is described along with the complete set of experimental data obtained during operation. 11 figures, 12 tables.

  14. Simulation of computational fluid dynamics in ozone contactor%臭氧接触池的计算流体力学模拟

    Institute of Scientific and Technical Information of China (English)

    王静; 邓保庆; 陆丽; 李勋栋

    2012-01-01

    The hydraulic characteristic of ozone contactor has a great impact on the disinfection effect of microorganism. Computational fluid dynamics ( CFD) technique was used to simulate the flow field of a single - column ozone contactor. The Eulerian multiphase model and the standard k - e turbulent model were used in the simulation. The results show that ozone distribution is relatively uniform in the single -column contactor. In general, there does not exist the phenomenon of "dead zone" , which helps to guarantee high disinfection efficiency. However, gas bubble was found to accumulate underneath the outlet trough. The results offer a sample for optimizing the ozonation system.%臭氧接触池的水力特性直接影响着微生物消毒效果.利用计算流体力学(CFD)技术,采用欧拉多相流模型和标准k-ε湍流模型对单管臭氧接触池内的流场进行数值模拟.结果表明:单管式臭氧接触池内臭氧分布比较均匀,基本上没有“死区”现象的产生,可以保证较高的消毒效率,但是气体气泡大量聚集在接触池出口槽下方.模拟结果对单管式臭氧接触池的优化有一定的借鉴作用.

  15. Integrated Control and Simulation of AC Contactor%交流接触器集成控制与仿真

    Institute of Scientific and Technical Information of China (English)

    庄杰榕; 许志红

    2014-01-01

    将集成控制技术引入交流接触器的控制中,以智能功率芯片为核心,集成跨周期调制电路和功率开关管,以132 kHz的高频工作模式,对交流接触器进行闭环控制。使用Multisim和LabView软件,建立智能控制下的接触器闭环机电一体化仿真系统。通过仿真系统分析瞬态特性,合理设计控制模块的工作模式,从底层分析高频工作方式引起电子器件产生的噪声及抑制措施,达到对电磁机构动作特性的良好控制,试验验证了集成方案的可行性。%This paper introduced integrated control technology to intelligent contactor control.The smart power IC built in internal power MOSFET and PSM circuit is the core of the control module.The control module works in the high frequency of 132 kHz to control the AC contactor with closed-loop.And using the software of Multisim and LabVIEW,the mechatronics simulation system of AC contactor with intelligent control was built.By means of the simulation system,this paper analyzed the working principle of control circuit and audio-frequency noise of electron device.The experiments were performed to verify the control module.

  16. Machine Tool Used AC Contactor Reliability Evaluation Method%机床用交流接触器可靠性评估方法

    Institute of Scientific and Technical Information of China (English)

    陆宾; 陆俭国

    2014-01-01

    Introduction was made to AC contactor reliability study development situations both at home and abroad. This paper described the reliability test method of machine tool used AC contactor mechanical operation and the evaluation method, pointing out that the product failure distribution type is Weibull distribution when AC contactor turning on/off the rating electrical load, failure rate is not constant, it is not suitable to adopt failure rate value as reliability index, but to adopt reliability measurement test, and the corresponding methods were given.%介绍了国内外开展交流接触器可靠性研究概况,阐述了机床用交流接触器机械操作可靠性试验方法与评估方法。指出交流接触器通断实际电气负载时产品失效分布类型为威布尔分布,失效率不是常数,不宜采用失效率大小作为交流接触器通断实际电气负载时的可靠性指标,而应采用可靠性测定试验,并给出了交流接触器通断实际电气负载时可靠性试验方法与提供可靠性数据的评估方法。

  17. Time delay controlled annular array transducers for omnidirectional guided wave mode control in plate like structures

    Science.gov (United States)

    Koduru, Jaya P.; Rose, Joseph L.

    2014-10-01

    Guided waves in plate like structures offer several modes with unique characteristics that can be taken advantage for nondestructive inspection applications. Conditions relating to the structure under inspection like the surrounding media, liquid loading, coatings etc require the use of special modes for successful inspection. Therefore, transducers that can excite mode controlled guided waves are essential for defect detection and discrimination in structures. Array transducers with annular elements can generate omnidirectional guided waves in plate like structures. However, the wave modes excited are limited to a particular wavelength governed by the element spacing. This limitation on the annular array transducers can be overcome by controlling the phase at each element relative to one another. In this work, annular array transducer construction techniques are theoretically examined and the optimum phase delays between the annular elements to excite a desired guided wave mode are calculated. A five element comb type annular array transducer is fabricated utilizing 1-3 type piezocomposite material. The mode control capability of the transducer is experimentally verified by selectively exciting the A0 and S0 guided wave modes in an aluminum plate like structure.

  18. Propagation characteristics of annular laser beams passing through the reflection Bragg grating with deformation

    Science.gov (United States)

    Yin, Suqin; Zhang, Bin; Dan, Youquan

    2011-06-01

    When high-power annular laser beams produced by the unstable resonator pass through the volume Bragg grating (VBG), absorption of light in the VBG will induce a temperature increment, resulting in changes in surface distortion. Considering that the surface distortion of the grating induces index and period differences, the scalar wave equations for the annular laser beams propagating in the VBG have been solved numerically and iteratively using finite-difference and sparse matrix methods. The variation in intensity distributions, the total power reflection coefficient, and the power in the bucket (PIB) for the annular laser beams passing through the reflection VBG with deformation have been analyzed quantitatively. It can be shown that the surface distortion of the VBG and the beam orders of the annular beams affect evidently the intensity distributions, the power reflection coefficient, and the PIB of the output beam. The peak intensity decreases as the deformation of the VBG increases. The total power reflection efficiency decreases significantly with the increase in deformations of the VBG. The PIB of the output beam decreases as the obscuration ratio β and the deformation of the VBG increase. For the given obscuration ratio β, the influence of deformation of reflection VBG on the PIB of the annular beams is more sensitive with increase in distortion of the VBG and decrease in beam order.

  19. Repeated mitral valve replacement in a patient with extensive annular calcification

    Directory of Open Access Journals (Sweden)

    Kitamura Tadashi

    2011-11-01

    Full Text Available Abstract Background Mitral valve replacement in the presence of severe annular calcification is a technical challenge. Case report A 47-year-old lady who had undergone mitral and aortic valve replacement for rheumatic disease 27 years before presented with dyspnea. At reoperation, extensive mitral annular calcification was hindering the disc motion of the Starr-Edwards mitral prosthesis. The old prosthesis was removed and a St Jude Medical mechanical valve was implanted after thorough annular debridement. Postoperatively the patient developed paravalvular leak and hemolytic anemia, subsequently undergoing reoperation three days later. The mitral valve was replaced with an Edwards MIRA valve, with a bulkier sewing cuff, after more aggressive annular debridement. Although initially there was no paravalvular leak, it recurred five days later. The patient also developed a small cerebral hemorrhage. As the paravalvular leak and hemolytic anemia gradually worsened, the patient underwent reoperation 14 days later. A Carpentier-Edwards bioprosthetic valve with equine pericardial patches, one to cover the debrided calcified annulus, another as a collar around the prosthesis, was used to eliminate paravalvular leak. At 7 years postoperatively the patient is doing well without any evidence of paravalvular leak or structural valve deterioration. Conclusion Mitral valve replacement using a bioprosthesis with equine pericardial patches was useful to overcome recurrent paravalvular leak due to severe mitral annular calcification.

  20. Hydraulic study of drilling fluid flow in circular and annular tubes

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    Scheid, C.M.; Calcada, L.A.; Braga, E.R.; Paraiso, E.C.H. [Universidade Federal Rural do Rio de Janeiro (PPGEQ/UFRRJ), Seropedica, RJ (Brazil). Programa de Pos-Graduacao em Engenharia Quimica. Dept. de Engenharia Qumica], E-mail: calcada@ufrrj.br; Martins, A. L. [Petroleo Brasileiro S.A. (CENPES/PETROBRAS), Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    2011-10-15

    This study investigates the drilling fluid flow behavior of two water-based drilling fluids in circular and annular tubes. The study has four main objectives: 1) to evaluate correlations between the Power Law and the Casson rheological models, 2) to characterize the flow behavior, 3) to evaluate five hydraulic-diameter equations, and 4) to evaluate the correlations of five turbulent flow-friction factors. The experimental fluid flow loop consisted of one positive displacement pump of 25 HP connected to a 500-liter tank agitated by a 3-HP mixer. The fluids passed through six meters long tubes, arranged in three horizontal rows with independent inlets and outlets. The circular tubes had a 1 inch diameter and were configured as two concentric annular tubes. Annular Tube I had an outer diameter of 1 1/4 inch and an inner diameter of 1/2 inch. Annular Tube II had an outer diameter of 2 inches and an inner diameter of 3/4 inch. The results show that, for the fluids in exam, correlations proposed in the literature were inaccurate as far as predicting hydraulic diameter, estimating pressure drop, and defining the flow regime. In general, the performance of those correlations depended on the fluid properties and on the system's geometry. Finally, literature parameters for some of the correlations were estimated for the two drilling fluids studied. These estimations improved the predictive capacity of calculating the friction factor for real drilling fluids applications for both circular and annular tubes. (author)