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Sample records for centrifugal separators

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Flow pattern in reverse-flow centrifugal separators

    NARCIS (Netherlands)

    Peng, W; Hoffmann, AC; Boot, PJAJ; Udding, A; Dries, HWA; Ekker, A; Kater, J

    2002-01-01

    Experimental flow patterns, determined by Laser Doppler Anemometry (LDA) for two types of reverse-flow centrifugal separators, are presented. The flow patterns in (a) a conventional cylinder-on-cone cyclone with tangential inlet and (b) a swirl tube with vane-generated swirl and a cylindrical body a

  9. Basic separative power of multi-component isotopes separation in a gas centrifuge

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Hongmin; Lei, Zengguang; Zhuge, Fu [Institute of Physical and Chemical Engineering, Tianjin (China)

    2008-07-01

    On condition that the overall separation factor per unit exists in centrifuge for multi-component isotopes separation, the relations between separative power of each component and molecular weight have been investigated in the paper while the value function and the separative power of binary-component separation are adopted. The separative power of each component is proportional to the square of the molecular weight difference between its molecular weight and the average molecular weight of other remnant components. In addition, these relations are independent on the number of the components and feed concentrations. The basic separative power and related expressions, suggested in the paper, can be used for estimating the separative power of each component and analyzing the separation characteristics. The most valuable application of the basic separative power is to evaluate the separative capacity of centrifuge for multi-component isotopes. (author)

  10. Fast centrifugal partition chromatography as a preparative-scale separation technique for citrus flavones

    Science.gov (United States)

    Fast centrifugal partition chromatography (FCPC) is a preparative-scale separations methodology based on the principles of counter current chromatography. Separations by FCPC are typically achieved with higher recoveries and with lower solvent use compared to conventional column chromatography. HSCP...

  11. Faults Analysis and Diagnosis of DR J-460 Dish Centrifugal Separator's Helical Gear

    Institute of Scientific and Technical Information of China (English)

    MA Xiao-jian; GAN Xue-hui

    2004-01-01

    The main faults of dish centrifugal separator's helical gear are described in this paper. In order to diagnose the DR J-460 dish centrifugal separator correctly, the vibration is tested with a helical gear under both normal and abnormal conditions. After comparing several general methods of the gear's fault feature extraction, a new convenient and effective method is presented on the basis of analyzing the vibration spectrum under different rotary velocities.

  12. Polymethylmethacrylate/Polyacrylonitrile Membranes via Centrifugal Spinning as Separator in Li-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Meltem Yanilmaz

    2015-04-01

    Full Text Available Electrospun nanofiber membranes have been extensively studied as separators in Li-ion batteries due to their large porosity, unique pore structure, and high electrolyte uptake. However, the electrospinning process has some serious drawbacks, such as low spinning rate and high production cost. The centrifugal spinning technique can be used as a fast, cost-effective and safe technique to fabricate high-performance fiber-based separators. In this work, polymethylmethacrylate (PMMA/polyacrylonitrile (PAN membranes with different blend ratios were produced via centrifugal spinning and characterized by using different electrochemical techniques for use as separators in Li-ion batteries. Compared with commercial microporous polyolefin membrane, centrifugally-spun PMMA/PAN membranes had larger ionic conductivity, higher electrochemical oxidation limit, and lower interfacial resistance with lithium. Centrifugally-spun PMMA/PAN membrane separators were assembled into Li/LiFePO4 cells and these cells delivered high capacities and exhibited good cycling performance at room temperature. In addition, cells using centrifugally-spun PMMA/PAN membrane separators showed superior C-rate performance compared to those using microporous polypropylene (PP membranes. It is, therefore, demonstrated that centrifugally-spun PMMA/PAN membranes are promising separator candidate for high-performance Li-ion batteries.

  13. Centrifugal separation and equilibration dynamics in an electron-antiproton plasma

    CERN Document Server

    Andresen, G B; Baquero-Ruiz, Marcelo; Bertsche, William; Bowe, Paul D; Butler, Eoin; Cesar, Claudio L; Chapman, Steven; Charlton, Michael; Deller, A; Eriksson, S; Fajans, Joel; Friesen, Tim; Fujiwara, Makoto C; Gill, David R; Gutierrez, A; Hangst, Jeffrey S; Hardy, Walter N; Hayden, Michael E; Humphries, Andrew J; Hydomako, Richard; Jonsell, Svante; Madsen, Niels; Menary, Scott; Nolan, Paul; Olin, Art; Povilus, Alexander; Pusa, Petteri; Robicheaux, Francis; Sarid, Eli; Silveira, Daniel M; So, Chukman; Storey, James W; Thompson, Robert I; van der Werf, Dirk P; Wurtele, Jonathan S; Yamazaki, Yasunori

    2011-01-01

    Charges in cold, multiple-species, non-neutral plasmas separate radially by mass, forming centrifugally-separated states. Here, we report the first detailed measurements of such states in an electron-antiproton plasma, and the first observations of the separation dynamics in any centrifugally-separated system. While the observed equilibrium states are expected and in agreement with theory, the equilibration time is approximately constant over a wide range of parameters, a surprising and as yet unexplained result. Electron-antiproton plasmas play a crucial role in antihydrogen trapping experiments.

  14. 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

  15. Two-phase (bio)catalytic reactions in a table-top centrifugal contact separator

    NARCIS (Netherlands)

    Kraai, Gerard N.; Zwol, Floris van; Schuur, Boelo; Heeres, Hero J.; Vries, Johannes G. de

    2008-01-01

    A new spin on catalysis: A table-top centrifugal contact separator allows for fast continuous two-phase reactions to be performed by intimately mixing two immiscible phases and then separating them. Such a device has been used to produce biodiesel from sunflower oil and MeOH/NaOMe. A lipase-catalyze

  16. Carnosol purification. Scaling-up centrifugal partition chromatography separations.

    Science.gov (United States)

    Bouju, Elodie; Berthod, Alain; Faure, Karine

    2016-09-30

    This paper illustrates the application of a recently proposed protocol allowing the scale-up prediction on hydrostatic countercurrent chromatography columns (centrifugal partition chromatographs or CPC). A commercial extract of rosemary (Rosmarinus officinalis L.) was used as the starting material containing 0.48% of carnosol, an active pharmaceutical ingredient with great potential. After a rapid method development on a small-scale 35-mL CPC instrument that allowed for the determination of the solvent system and maximum sample concentration and volume, the purification was transferred on two larger instruments using the "free space between peaks" method. The method takes into account the technical limitations of the larger instruments, such as pressure and/or maximum centrifugal field, and allows, by simply running an analytical-sized injection on the large scale rotor, to give an accurate prediction of the maximum sample load and best throughput. The 0.27g of rosemary extract maximum load on a 35-mL CPC was transferred as a 1.9g load on a 254-mL medium size CPC and 9g load on a 812-mL CPC. The maximum process efficiency of 3.1mg of carnosol per hour obtained on the small 35-mL column was transferred on the 254-mL CPC giving 8.3mg/h and, on the larger 812-mL column 49.4mg of carnosol could be obtained per hour. If the scaling-up in CPC instruments is not directly homothetic, it can be highly predictable through a few simple experiments.

  17. 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.

  18. Process Intensification. Continuous Two-Phase Catalytic Reactions in a Table-Top Centrifugal Contact Separator

    NARCIS (Netherlands)

    Kraai, Gerard N.; Schuur, Boelo; van Zwol, Floris; Haak, Robert M.; Minnaard, Adriaan J.; Feringa, Ben L.; Heeres, Hero J.; de Vries, Johannes G.; Prunier, ML

    2009-01-01

    Production of fine chemicals is mostly performed in batch reactors. Use of continuous processes has many advantages which may reduce the cost of production. We have developed the use of centrifugal contact separators (CCSs) for continuous two-phase catalytic reactions. This equipment has previously

  19. 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

  20. 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

  1. Performance of different analytical methods in evaluating grade efficiency of centrifugal separators

    NARCIS (Netherlands)

    Ray, MB; Hoffmann, AC; Postma, RS

    2000-01-01

    In this paper results are presented from four different particle size analysis techniques used to characterize the performance of a novel centrifugal gas-solid separator. The Post Cyclone (PoC), is a new secondary collector situated at the top of a conventional reverse flow cyclone which utilizes th

  2. Integrated reactor and centrifugal separator and uses thereof

    Science.gov (United States)

    Birdwell, Jr., Joseph F; Jennings, Harold L.; McFarlane, Joanna; Tsouris, Constantino

    2012-01-17

    An apparatus for providing reaction of fluids and separation of products with increased residence time. The apparatus includes a stationary shell, a rotating hollow cylindrical component disposed in the stationary shell, a residence-time increasing device external to the stationary shell, a standpipe for introducing fluid into an interior cavity of the hollow cylindrical component from the residence-time increasing device, a first outlet in fluid flow communication with the interior cavity of the hollow cylindrical component for a less dense phase fluid, and a second outlet in fluid flow communication with the interior cavity of the hollow cylindrical component for a more dense phase fluid.

  3. Separation of Bacteria, Protozoa and Carbon Nanotubes by Density Gradient Centrifugation

    Directory of Open Access Journals (Sweden)

    Monika Mortimer

    2016-10-01

    Full Text Available Sustainable production and use of carbon nanotube (CNT-enabled materials require efficient assessment of CNT environmental hazards, including the potential for CNT bioaccumulation and biomagnification in environmental receptors. Microbes, as abundant organisms responsible for nutrient cycling in soil and water, are important ecological receptors for studying the effects of CNTs. Quantification of CNT association with microbial cells requires efficient separation of CNT-associated cells from individually dispersed CNTs and CNT agglomerates. Here, we designed, optimized, and demonstrated procedures for separating bacteria (Pseudomonas aeruginosa from unbound multiwall carbon nanotubes (MWCNTs and MWCNT agglomerates using sucrose density gradient centrifugation. We demonstrate separation of protozoa (Tetrahymena thermophila from MWCNTs, bacterial agglomerates, and protozoan fecal pellets by centrifugation in an iodixanol solution. The presence of MWCNTs in the density gradients after centrifugation was determined by quantification of 14C-labeled MWCNTs; the recovery of microbes from the density gradient media was confirmed by optical microscopy. Protozoan intracellular contents of MWCNTs and of bacteria were also unaffected by the designed separation process. The optimized methods contribute to improved efficiency and accuracy in quantifying MWCNT association with bacteria and MWCNT accumulation in protozoan cells, thus supporting improved assessment of CNT bioaccumulation.

  4. Separation of Bacteria, Protozoa and Carbon Nanotubes by Density Gradient Centrifugation

    Science.gov (United States)

    Mortimer, Monika; Petersen, Elijah J.; Buchholz, Bruce A.; Holden, Patricia A.

    2016-01-01

    Sustainable production and use of carbon nanotube (CNT)-enabled materials require efficient assessment of CNT environmental hazards, including the potential for CNT bioaccumulation and biomagnification in environmental receptors. Microbes, as abundant organisms responsible for nutrient cycling in soil and water, are important ecological receptors for studying the effects of CNTs. Quantification of CNT association with microbial cells requires efficient separation of CNT-associated cells from individually dispersed CNTs and CNT agglomerates. Here, we designed, optimized, and demonstrated procedures for separating bacteria (Pseudomonas aeruginosa) from unbound multiwall carbon nanotubes (MWCNTs) and MWCNT agglomerates using sucrose density gradient centrifugation. We demonstrate separation of protozoa (Tetrahymena thermophila) from MWCNTs, bacterial agglomerates, and protozoan fecal pellets by centrifugation in an iodixanol solution. The presence of MWCNTs in the density gradients after centrifugation was determined by quantification of 14C-labeled MWCNTs; the recovery of microbes from the density gradient media was confirmed by optical microscopy. Protozoan intracellular contents of MWCNTs and of bacteria were also unaffected by the designed separation process. The optimized methods contribute to improved efficiency and accuracy in quantifying MWCNT association with bacteria and MWCNT accumulation in protozoan cells, thus supporting improved assessment of CNT bioaccumulation. PMID:27917301

  5. Experimental Research on Desulfurization of Fine Coal Using an Enhanced Centrifugal Gravity Separator

    Institute of Scientific and Technical Information of China (English)

    TAO You-jun; LUO Zhen-fu; ZHAO Yue-min; TAO Daniel

    2006-01-01

    A desulphurization experimental study under the effects of compounding physical force fields has been described for < 0.5 mm fine particles of high sulfur coal. A statistical test using the Box-Behnken Design of experiments was conducted to evaluate the effects of individual operating variables and their interactions on desulfurization of fine coal using an enhanced centrifugal gravity separator. A model describing the relation between desulphurization efficiency of pyrite sulfur and different operating variables has been designed. The interactions between different factors on the pyrite sulfur desulphurization efficiency have been analysed. The optimal test conditions for desulfarization are extracted from the Design-Expert 6.0 software. Finally, the advantage of centrifugal gravity separation for fine coal is pointed out.

  6. Analysis and optimization of gas-centrifugal separation of uranium isotopes by neural networks

    Directory of Open Access Journals (Sweden)

    Migliavacca S.C.P.

    2002-01-01

    Full Text Available Neural networks are an attractive alternative for modeling complex problems with too many difficulties to be solved by a phenomenological model. A feed-forward neural network was used to model a gas-centrifugal separation of uranium isotopes. The prediction showed good agreement with the experimental data. An optimization study was carried out. The optimal operational condition was tested by a new experiment and a difference of less than 1% was found.

  7. Removal of primary iron rich phase from aluminum-silicon melt by centrifugal separation

    Directory of Open Access Journals (Sweden)

    Seong Woo Kim

    2013-03-01

    Full Text Available Recycling is a major consideration in continued aluminum use due to the enormous demand for high quality products. Some impurity elements gradually accumulate through the repetitive reuse of aluminum alloy scrap. Of them, the iron content should be suppressed under the allowed limit. In the present research, a novel separation method was introduced to remove primary iron-rich intermetallic compounds by centrifugation during solidification of Al-Si-Fe alloys. This method does not use the density difference between two phases as in other centrifugal methods, but uses the order of solidification in Al-Si-Fe alloys, because iron promotes the formation of intermetallic compounds with other alloying elements as a primary phase. Two Al-Si-Fe alloys which have different iron contents were chosen as the starting materials. The iron-rich phase could be efficiently removed by centrifuging under a centrifugal force of 40 g. Coarse intermetallic compounds were found in the sample inside the crucible, while rather fine intermetallic compounds were found in the sample outside the crucible. Primary intermetallic compounds were linked to each other via aluminum-rich matrix, and formed like a network. The highest iron removal fraction is 67% and the lowest one is 7% for Al-12Si-1.7Fe alloy. And they are 82% and 18% for Al-12Si-3.4Fe alloy, respectively.

  8. Analysis and testing the performance of a centrifugal two phase flow separator

    Energy Technology Data Exchange (ETDEWEB)

    Mirza-Moghadam, A V

    1979-01-01

    Analysis and testing the performance of an 8 in., 1.72 ft high centrifugal cyclone separator for flows up to 4.0 lbs/s and pressures ranging from 10 to 60 psig. Conclusions drawn are based on inlet steam qualities of 23 to 27 percent (x% = m/sub s//m /sub t/) .99% and better steam quality is achieved up to 3 lbs/s under 50 and 60 psig. Breakdown flow rate is found to be a linear function of separator pressure.

  9. A critical evaluation of Amicon Ultra centrifugal filters for separating proteins, drugs and nanoparticles in biosamples.

    Science.gov (United States)

    Johnsen, Elin; Brandtzaeg, Ole Kristian; Vehus, Tore; Roberg-Larsen, Hanne; Bogoeva, Vanya; Ademi, Ornela; Hildahl, Jon; Lundanes, Elsa; Wilson, Steven Ray

    2016-02-20

    Amicon(®) Ultra centrifugal filters were critically evaluated for various sample preparations, namely (a) proteome fractionation, (b) sample cleanup prior to liquid chromatography mass spectrometry (LC-MS) measurement of small molecules in cell lysate, and (c) separating drug-loaded nanoparticles and released drugs for accurate release profiling in biological samples. (a) Filters of supposedly differing molar mass (MM) selectivity (10, 30, 50 and 100K) were combined to attempt fractionation of samples of various complexity and concentration. However, the products had surprisingly similar MM retentate/filtrate profiles, and the filters were unsuited for proteome fractionation. (b) Centrifugal filtration was the only clean-up procedure in a FDA-guideline validated LC-MS method for determining anti-tuberculosis agents rifampicin and thioridazine in macrophage cell lysate. An additional organic solvent washing step (drug/protein-binding disruption) was required for satisfactory recovery. (c) The centrifugation filters are well suited for separating drugs and nanoparticles in simple aqueous solutions, but significantly less so for biological samples, as common drug-protein binding disruptors can dissolve NPs or be incompatible with LC-MS instrumentation.

  10. Prediction and optimization of the recovery rate in centrifugal separation of platelet-rich plasma (PRP)

    Science.gov (United States)

    Piao, Linfeng; Park, Hyungmin; Jo, Chris

    2016-11-01

    We present a theoretical model of the recovery rate of platelet and white blood cell in the process of centrifugal separation of platelet-rich plasma (PRP). For the practically used conditions in the field, the separation process is modeled as a one-dimensional particle sedimentation; a quasi-linear partial differential equation is derived based on the kinematic-wave theory. This is solved to determine the interface positions between supernatant-suspension and suspension-sediment, used to estimate the recovery rate of the plasma. While correcting the Brown's hypothesis (1989) claiming that the platelet recovery is linearly proportional to that of plasma, we propose a new correlation model for prediction of the platelet recovery, which is a function of the volume of whole blood, centrifugal acceleration and time. For a range of practical parameters, such as hematocrit, volume of whole blood and centrifugation (time and acceleration), the predicted recovery rate shows a good agreement with available clinical data. We propose that this model is further used to optimize the preparation method of PRP that satisfies the customized case. Supported by a Grant (MPSS-CG-2016-02) through the Disaster and Safety Management Institute funded by Ministry of Public Safety and Security of Korean government.

  11. Recovery of materials from waste printed circuit boards by vacuum pyrolysis and vacuum centrifugal separation.

    Science.gov (United States)

    Zhou, Yihui; Wu, Wenbiao; Qiu, Keqiang

    2010-11-01

    In this research, a two-step process consisting of vacuum pyrolysis and vacuum centrifugal separation was employed to treat waste printed circuit boards (WPCBs). Firstly, WPCBs were pyrolysed under vacuum condition at 600 °C for 30 min in a lab-scale reactor. Then, the obtained pyrolysis residue was heated under vacuum until the solder was melted, and then the molten solder was separated from the pyrolysis residue by the centrifugal force. The results of vacuum pyrolysis showed that the type-A of WPCBs (the base plates of which was made from cellulose paper reinforced phenolic resin) pyrolysed to form an average of 67.97 wt.% residue, 27.73 wt.% oil, and 4.30 wt.% gas; and pyrolysis of the type-B of WPCBs (the base plates of which was made from glass fiber reinforced epoxy resin) led to an average mass balance of 72.20 wt.% residue, 21.45 wt.% oil, and 6.35 wt.% gas. The results of vacuum centrifugal separation showed that the separation of solder was complete when the pyrolysis residue was heated at 400 °C, and the rotating drum was rotated at 1200 rpm for 10 min. The pyrolysis oil and gas can be used as fuel or chemical feedstock after treatment. The pyrolysis residue after solder separation contained various metals, glass fibers and other inorganic materials, which could be recycled for further processing. The recovered solder can be reused directly and it can also be a good resource of lead and tin for refining.

  12. Theoretical and numerical analysis of coal dust separated by centrifugal force for working and heading faces

    Institute of Scientific and Technical Information of China (English)

    Shiqiang Chen; Haiqiao Wang; Yiqun Li; Haijiao Cui; Jie Zhao; Xiaowei Zhang

    2014-01-01

    In order to meet engineering needs of Chinese underground coal mines, a new dust-collecting fan, a device of dust separated by centrifugal force in driven cyclone passageway (DCCP) was designed. In centrifugal dust removal section (CDRS) of DCCP, a general equation is derived from the principle of force equilibrium. According to CDRS structure parameters and fan running parameters, the general equation is simplified, and the simplest equation is calculated numerically by MATLAB. The calculation results illustrate that increasing quantity of air current is against dust removal, but it is beneficial to dust removal by increasing the radius of driven spiral blade and increasing the particle diameter of coal dust. The conclusions show that the dust-collecting structure parameters coupled with the fan running parameters is a novel optimization approach to dust-collection fan for working and heading faces, which is especially suitable for Chinese underground mines.

  13. Centrifugal partition chromatography in a biorefinery context: Separation of monosaccharides from hydrolysed sugar beet pulp.

    Science.gov (United States)

    Ward, David P; Cárdenas-Fernández, Max; Hewitson, Peter; Ignatova, Svetlana; Lye, Gary J

    2015-09-11

    A critical step in the bioprocessing of sustainable biomass feedstocks, such as sugar beet pulp (SBP), is the isolation of the component sugars from the hydrolysed polysaccharides. This facilitates their subsequent conversion into higher value chemicals and pharmaceutical intermediates. Separation methodologies such as centrifugal partition chromatography (CPC) offer an alternative to traditional resin-based chromatographic techniques for multicomponent sugar separations. Highly polar two-phase systems containing ethanol and aqueous ammonium sulphate are examined here for the separation of monosaccharides present in hydrolysed SBP pectin: l-rhamnose, l-arabinose, d-galactose and d-galacturonic acid. Dimethyl sulfoxide (DMSO) was selected as an effective phase system modifier improving monosaccharide separation. The best phase system identified was ethanol:DMSO:aqueous ammonium sulphate (300gL(-1)) (0.8:0.1:1.8, v:v:v) which enabled separation of the SBP monosaccharides by CPC (200mL column) in ascending mode (upper phase as mobile phase) with a mobile phase flow rate of 8mLmin(-1). A mixture containing all four monosaccharides (1.08g total sugars) in the proportions found in hydrolysed SBP was separated into three main fractions; a pure l-rhamnose fraction (>90%), a mixed l-arabinose/d-galactose fraction and a pure d-galacturonic acid fraction (>90%). The separation took less than 2h demonstrating that CPC is a promising technique for the separation of these sugars with potential for application within an integrated, whole crop biorefinery.

  14. An improved turbulence model for separation flow in a centrifugal pump

    Directory of Open Access Journals (Sweden)

    Yun Ren

    2016-06-01

    Full Text Available For the stable and reliable operation of centrifugal pump, the transient flow must be studied and the separation region should be avoided. Three-dimensional, incompressible, steady, and transient flows in a centrifugal pump at specific speed within 74 were numerically studied using shear stress transport k-ω turbulence model, and an improved explicit algebraic Reynolds stress model–rotation-curvature turbulence model was proposed by considering the effects of rotation and curvature in the impeller passages in this work. Steady and transient computations were conducted to compare with the experiments. The comparison of pump hydraulic performance showed that the explicit algebraic Reynolds stress model–rotation-curvature turbulence model was better than the original model, especially between 0.6QBEP and 1.2QBEP; the improved model could enhance the head prediction of pump by about 1%–7% than that with the original model. Then, the visualization of the vortex evolution was observed to validate the unsteady simulations. Good agreement was investigated between calculations and visualizations. It is indicated that the explicit algebraic Reynolds stress model–rotation-curvature model can successfully capture the separation flow.

  15. 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.

  16. Linear polymer separation using carbon-nanotube-modified centrifugal filter units.

    Science.gov (United States)

    Krawczyk, Tomasz; Marian, Karolina; Pawlyta, Mirosława

    2016-02-01

    The separation of linear polymers such as polysaccharides and polyethylene glycol was performed with modified commercial centrifugal filter units. The deposition of a 0.16-0.35 μm layer of modified carbon nanotubes prevented permeation of linear polymers of molecular weight higher than 20 000 Da through the membrane. It allowed facile purification of solution of 0.1 g of polymer samples from small molecules within 25 min by using a bench-top centrifuge. The structure of modified carbon nanotubes was optimized in order to achieve good adhesion to the low binding regenerated cellulose surface and low solubility in aqueous solutions after deposition. The best modification of carbon nanotubes was oxidation and subsequent amide formation of diethanolamine. Introduction of acetic acid groups using sodium chloroacetate worked equally well. The modified filter could be used multiple times without the decrease of the efficiency. The carbon nanotubes layer was stable in aqueous solutions in a pH range of 1-7. The proposed method provides a convenient way of purification of modified polymers in research areas such as drug delivery or macromolecular probes synthesis.

  17. Alternative separation steps for monoclonal antibody purification: combination of centrifugal partitioning chromatography and precipitation.

    Science.gov (United States)

    Oelmeier, Stefan A; Ladd-Effio, Christopher; Hubbuch, Jürgen

    2013-12-01

    Protein drugs continue to grow both in medicinal importance as in scale of their production. This furthers the interest in separation technologies that have the potential to replace chromatographic steps in a protein purification process. Two such unit operations that are employed in large scale in the chemical industry are extraction and precipitation. Their usefulness for the purification of proteins has been demonstrated, but the integration of such unit operations in a way that generate an output stream of high protein concentration and low process related impurities was missing. In this work, we employ centrifugal partitioning chromatography ('CPC') in combination with precipitation of the protein of interest to purify a cell culture supernatant of a monoclonal antibody producing cell line. Centrifugal partitioning chromatography was used as means of multi-step extraction using aqueous two-phase systems and was able to remove up to 88.2% of host cell protein ('HCP'). The following PEG driven precipitation and resolubilization of the protein of interest was use to condition the CPC output stream to suit subsequent chromatographic steps, to increase mAb concentration, remove the phase forming polymer, further improve HCP clearance, and integrate a low pH hold step for viral clearance. The entire process reduced HCP content by 99.4% while recovering 93% of the protein of interest. High throughput screening techniques were extensively employed during the development of the process.

  18. Highly Efficient and Scalable Separation of Semiconducting Carbon Nanotubes via Weak Field Centrifugation

    Science.gov (United States)

    Reis, Wieland G.; Weitz, R. Thomas; Kettner, Michel; Kraus, Alexander; Schwab, Matthias Georg; Tomović, Željko; Krupke, Ralph; Mikhael, Jules

    2016-05-01

    The identification of scalable processes that transfer random mixtures of single-walled carbon nanotubes (SWCNTs) into fractions featuring a high content of semiconducting species is crucial for future application of SWCNTs in high-performance electronics. Herein we demonstrate a highly efficient and simple separation method that relies on selective interactions between tailor-made amphiphilic polymers and semiconducting SWCNTs in the presence of low viscosity separation media. High purity individualized semiconducting SWCNTs or even self-organized semiconducting sheets are separated from an as-produced SWCNT dispersion via a single weak field centrifugation run. Absorption and Raman spectroscopy are applied to verify the high purity of the obtained SWCNTs. Furthermore SWCNT - network field-effect transistors were fabricated, which exhibit high ON/OFF ratios (105) and field-effect mobilities (17 cm2/Vs). In addition to demonstrating the feasibility of high purity separation by a novel low complexity process, our method can be readily transferred to large scale production.

  19. Preparative separation of glycoalkaloids α-solanine and α-chaconine by centrifugal partition chromatography.

    Science.gov (United States)

    Attoumbré, Jacques; Lesur, David; Giordanengo, Philippe; Baltora-Rosset, Sylvie

    2012-11-01

    The main glycoalkaloids of a commercial potato cultivar, α-chaconine and α-solanine, were extracted from sprouts of Solanum tuberosum cv. Pompadour by a mixture of MeOH/H(2)O/CH(3)COOH (400/100/50, v/v/v). In these conditions, 2.8±0.62g of crude extract were obtained from 50g of fresh sprouts and the total glycoalkaloid content was determined by analytical HPLC at 216.5mg/100g. α-Chaconine and α-solanine were separated in a preparative scale using centrifugal partition chromatography (CPC). In a solvent system composed of a mixture of ethyl acetate/butanol/water (15/35/50, v/v/v), α-chaconine (54mg) and α-solanine (15mg) were successfully isolated from the crude extract in one step of purification. The purity of isolated compounds was determined to be higher than 92% by HPLC analysis.

  20. Performance enhancement of open loop gas recovery process by centrifugal separation of gases

    Science.gov (United States)

    Kalmani, S. D.; Joshi, A. V.; Bhattacharya, S.; Hunagund, P. V.

    2016-11-01

    The proposed INO-ICAL detector [1] is going to be instrumented with 28800 RPCs (Resistive Plate Chamber). These RPCs (2 × 2 m2 size) will consist of two glass electrodes separated by 2 mm and will use a gas mixture of Freon R134a, isobutane and sulphur hexafluoride (in the ratio of 95.3:4.5:0.2). An Open Ended System (OES), in which the gas mixture is vented to the atmosphere after a single passage through the detector, is most commonly used for small detector setups. However, OES cannot be used with the INO-ICAL detector due to reasons of cost and pollution. It is necessary, therefore, to recirculate the gas mixture in a closed loop. In a Closed Loop gas System (CLS) [2] the gas mixture is purified and recirculated after flowing through the RPC. The impurities which get accumulated in the gas mixture due to leaks or formation of radicals are removed by suitable filters. The Open Loop System (OLS) [3] is based on the separation and recovery of major gas components after passage of the gas mixture through the RPCs. and has the advantage that it does not need filters for removal of impurities. However a CLS is found to be more efficient than OLS in the recovery of gases in the mixture. In this paper we discuss centrifugal separation [4] as a technique to extract major gas constituents and use this technique to improve the efficiency of OLS. Results from preliminary trial runs are reported.

  1. Effect of Coriolis force on counter-current chromatographic separation by centrifugal partition chromatography.

    Science.gov (United States)

    Ikehata, Jun-Ichi; Shinomiya, Kazufusa; Kobayashi, Koji; Ohshima, Hisashi; Kitanaka, Susumu; Ito, Yoichiro

    2004-02-06

    The effect of Coriolis force on the counter-current chromatographic separation was studied using centrifugal partition chromatography (CPC) with four different two-phase solvent systems including n-hexane-acetonitrile (ACN); tert-butyl methyl ether (MtBE)-aqueous 0.1% trifluoroacetic acid (TFA) (1:1); MtBE-ACN-aqueous 0.1% TFA (2:2:3); and 12.5% (w/w) polyethylene glycol (PEG) 1000-12.5% (w/w) dibasic potassium phosphate. Each separation was performed by eluting either the upper phase in the ascending mode or the lower phase in the descending mode, each in clockwise (CW) and counterclockwise column rotation. Better partition efficiencies were attained by the CW rotation in both mobile phases in all the two-phase solvent systems examined. The mathematical analysis also revealed the Coriolis force works favorably under the CW column rotation for both mobile phases. The overall results demonstrated that the Coriolis force produces substantial effects on CPC separation in both organic-aqueous and aqueous-aqueous two-phase systems.

  2. Feedback Control and Dynamic Behaviour of Z-Source Converter Fed Separately Excited DC Motor and Centrifugal Pump Set

    Directory of Open Access Journals (Sweden)

    Saswati Swapna Dash

    2014-07-01

    Full Text Available This paper presents an overall study of Feedback Control of Z-Source Converter Fed Separately excited DC motor with centrifugal Pump Set. Z-source converter can be used for both voltage buck and boost mode using LC impedance network. In this paper the dynamic modeling of Z-source with motor load and centrifugal pump set is carried out with new findings. The compensators for speed feedback loop are designed by taking average state space analysis and small signal model of the system. The feedback loop is designed by classical control methods. The experiment is done in MATLAB work environment and the result is verified by Simulation.

  3. Numerical Investigation of Cell Encapsulation for Multiplexing Diagnostic Assays Using Novel Centrifugal Microfluidic Emulsification and Separation Platform

    Directory of Open Access Journals (Sweden)

    Yong Ren

    2016-01-01

    Full Text Available In the present paper, we report a novel centrifugal microfluidic platform for emulsification and separation. Our design enables encapsulation and incubation of multiple types of cells by droplets, which can be generated at controlled high rotation speed modifying the transition between dripping-to-jetting regimes. The droplets can be separated from continuous phase using facile bifurcated junction design. A three dimensional (3D model was established to investigate the formation and sedimentation of droplets using the centrifugal microfluidic platform by computational fluid dynamics (CFD. The simulation results were compared to the reported experiments in terms of droplet shape and size to validate the accuracy of the model. The influence of the grid resolution was investigated and quantified. The physics associated with droplet formation and sedimentation is governed by the Bond number and Rossby number, respectively. Our investigation provides insight into the design criteria that can be used to establish centrifugal microfluidic platforms tailored to potential applications, such as multiplexing diagnostic assays, due to the unique capabilities of the device in handling multiple types of cells and biosamples with high throughput. This work can inspire new development of cell encapsulation and separation applications by centrifugal microfluidic technology.

  4. Practice of centrifugal stable isotope separation for experiments in neutrino physics

    Energy Technology Data Exchange (ETDEWEB)

    Tikhomirov, A.V. [Kurchatov Institute, Moscow (Russian Federation)

    1994-12-31

    Results of xenon 136, germanium 76 and chromium 50 enrichment with the use of centrifuge cascades are presented. The isotopes are meant for use in experiments in neutrino physics. Tens of kilograms of these isotopes have been produced in Russia, with an enrichment level of an order of magnitude or higher with respect to their natural content. Practical possibilities of using the centrifugal technique both for neutrino investigation and other applications are outlined. 2 tabs., 9 refs.

  5. Separation of active laccases from Pleurotus sapidus culture supernatant using aqueous two-phase systems in centrifugal partition chromatography.

    Science.gov (United States)

    Schwienheer, C; Prinz, A; Zeiner, T; Merz, J

    2015-10-01

    For the production of bio active compounds, e.g., active enzymes or antibodies, a conserved purification process with a minimum loss of active compounds is necessary. In centrifugal partition chromatography (CPC), the separation effect is based on the different distribution of the components to be separated between two immiscible liquid phases. Thereby, one liquid phase is kept stationary in chambers by a centrifugal field and the mobile phase is pumped through via connecting ducts. Aqueous two phase systems (ATPS) are known to provide benign conditions for biochemical products and seem to be promising when used in CPC for purification tasks. However, it is not known if active biochemical compounds can "survive" the conditions in a CPC where strong shear forces can occur due to the two-phasic flow under centrifugal forces. Therefore, this aspect has been faced within this study by the separation of active laccases from a fermentation broth of Pleurotus sapidus. After selecting a suitable ATPS and operating conditions, the activity yield was calculated and the preservation of the active enzymes could be observed. Therefore, CPC could be shown as potentially suitable for the purification of bio-active compounds.

  6. Applied catastrophic phase inversion: a continuous non-centrifugal phase separation step in biphasic whole-cell biocatalysis.

    Science.gov (United States)

    Glonke, Sebastian; Sadowski, Gabriele; Brandenbusch, Christoph

    2016-11-01

    Biphasic whole-cell biotransformations are known to be efficient alternatives to common chemical synthesis routes, especially for the production of, e.g. apolar enantiopure organic compounds. They provide high stereoselectivity combined with high product concentrations owing to the presence of an organic phase serving as substrate reservoir and product sink. Industrial implementation suffers from the formation of stable Pickering emulsions caused by the presence of cells. State-of-the-art downstream processing includes inefficient strategies such as excessive centrifugation, use of de-emulsifiers or thermal stress. In contrast, using the catastrophic phase inversion (CPI) phenomenon (sudden switch of emulsion type caused by addition of dispersed phase), Pickering-type emulsions can be destabilized efficiently. Within this work a model system using bis(2-ethylhexyl) phthalate (BEHP) as organic phase in combination with E. coli, JM101 was successfully separated using a continuous mixer settler setup. Compared to the state-of-the-art centrifugal separations, this process allows complete phase separation with no detectable water content or cells in the organic phase with no utilities/additives required. Furthermore, the concentration of the product is not affected by the separation. It is therefore a simple applicable method that can be used for separation of stable Pickering-type emulsions based on the knowledge of the point of inversion.

  7. Investigation, comparison and design of chambers used in centrifugal partition chromatography on the basis of flow pattern and separation experiments.

    Science.gov (United States)

    Schwienheer, C; Merz, J; Schembecker, G

    2015-04-17

    In centrifugal partition chromatography (CPC) the separation efficiency is mainly influenced by the hydrodynamic of mobile and stationary phase in the chambers. Thus, the hydrodynamic has to be investigated and understood in order to enhance a CPC separation run. Different chamber geometries have been developed in the past and the influence of several phase systems and CPC operating conditions were investigated for these chambers. However, a direct comparison between the different chamber types has not been performed yet. In order to investigate the direct influence of the chamber design on the hydrodynamic, several chamber designs - partially similar in geometry to commercial available designs - are investigated under standardized conditions in the present study. The results show the influence of geometrical aspects of the chamber design on the hydrodynamic and therewith, on the separation efficiency. As a conclusion of the present study, some ideas for an optimal chamber design for laboratory and industrial purpose are proposed.

  8. The Structure of Centrifugal Separator and its Control System%离心选矿机结构及其控制方法

    Institute of Scientific and Technical Information of China (English)

    李华杰

    2012-01-01

    Centrifugal separator is a kind of gravity separation equipment developed in the 1960s for dressing of low-grade and fine grained mineral. With the progress of technology, the integrated ore dressing technology with centrifugal separator has been gradually improved. The application of advanced automatic control technology make the working process of centrifugal separator more reliable and convenient, which greatly enhanced ore dressing performance of centrifugal separator. This article introduces the structure, components, working principle and automatic control system of centrifugal separator.%离心选矿机是国内60年代研制出的一种重选设备,适用于低品位、细粒级的钨矿石选别.随着技术的进步,离心选矿机选矿的综合技术日趋完善,特别是先进的自动控制技术的应用,使得离心选矿机的工作过程稳定可靠、调节方便,大大提升了离心选矿机的选矿效果.本文介绍了离心选矿机的结构组成、工作原理和自动控制系统.

  9. Plasma centrifuge with vacuum arc discharge applied to the separation of stable isotopes

    Science.gov (United States)

    Delbosco, Edson

    1989-09-01

    The results of a vacuum-arc plasma centrifuge experiment are described. A plasma centrifuge is an apparatus where a plasma column is produced due to the interaction of an electric current with an externally applied magnetic field, vector J x vector B. Among the applications of a rotating plasma, this work deals particularly with its utilization in an isotope enrichment device. The main characteristics of the plasma produced in this experiment are presented, with special attention to the plasma column rotation and the isotope enrichment. The analysis of the results is performed using a fluid model for a completely ionized rigid body rotating plasma column in steady state equilibrium. The main results are: (1) rotation frequency of the plasma column in the range 2 x (exp 4) to 3 x 10 (exp 5) rad/s; (2) enrichment of 10 to 30 pct for the magnesium isotopes, and 290 to 490 pct for the carbon-13 isotope; (3) rigid body rotation of the plasma column only for radii smaller than the characteristic radius of the plasma column, r(sub e); (4) linear dependence of the rotation frequency upon the magnetic field strength only for r is less than r(sub e); (5) existence of an optimum value of the magnetic field for maximum enrichment; and (6) dependence of the rotation frequency upon the inverse of the atomic mass.

  10. Comparison [(3)H]-flumazenil binding parameters in rat cortical membrane using different separation methods, filtration and centrifugation.

    Science.gov (United States)

    Ahmadi, Fatemeh; Faizi, Mehrdad; Tabatabai, Sayyed Abbas; Beiki, Davood; Shahhosseini, Soraya

    2013-10-01

    Radioligand receptor binding assays are a common method to evaluate the affinity of newly synthesized benzodiazepine ligands for the receptor. [(3)H]-flumazenil is an antagonist of benzodiazepine receptors and is generally used as a radioligand. In this study, the binding parameters of [(3)H]-flumazenil to rat cortical membranes were evaluated using two separation methods: filtration with GF/C filters and centrifugation. Additionally, the effects of vacuum pressure, exposure time to the cocktail, and geometry on the filtration method were studied. The binding parameters of [(3)H]-flumazenil (Kd and Bmax) were determined through saturation studies using two methods. The results from this study showed that the filtration method is time consuming and requires more steps to be completed. Because filtration causes partial elution of bound [(3)H]-flumazenil into the liquid scintillation cocktail, the results are not reproducible, which result in inaccurate estimation of the binding parameters. The centrifugation method in contrast to filtration is straightforward and produces reproducible as well as reliable results, all of the steps are performed in a single polypropylene tube, which eliminates the loss of tissue and avoids other systematic errors associated with transfer and handling.

  11. Isotopic separation by centrifugation. Rotating plasma; Separacion Isotopic por Centrifugacion Plasma Rotante

    Energy Technology Data Exchange (ETDEWEB)

    Perello, M.; Vigon, M. A.

    1972-07-01

    The motion of a gas simultaneously submitted to an electric discharge and magnetic field has been studied in order to analyze the possibility of producing isotopes separation by rotation of a plasma. Some experimental results obtained under different discharge conditions are also given. Differences of pressure up to 15 mm oil between both electrodes has been attained. No definite conclusion on separation factors could be reached because of the low reproducibility of results, probably due to the short duration of the discharge with a new chamber designed to support stronger thermal shocks more reliable data can be expected. (Author) 16 refs.

  12. Development of a centrifugal in-line separator for oil-water flows

    NARCIS (Netherlands)

    Slot, J.J.

    2013-01-01

    The world energy consumption will increase in the next decades. However, many aging oil fields are showing a steady decline in oil production. And they are producing increasing amounts of water, making the separation of the oil from the oil-water mixture an important processing step. In-line separa

  13. 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%.

  14. High-speed, high-purity separation of gold nanoparticle-DNA origami constructs using centrifugation.

    Science.gov (United States)

    Ko, Seung Hyeon; Vargas-Lara, Fernando; Patrone, Paul N; Stavis, Samuel M; Starr, Francis W; Douglas, Jack F; Liddle, J Alexander

    2014-10-01

    DNA origami is a powerful platform for assembling gold nanoparticle constructs, an important class of nanostructure with numerous applications. Such constructs are assembled by the association of complementary DNA oligomers. These association reactions have yields of 90%. The gold nanoparticles play a number of critical roles in our system, functioning not only as integral components of the purified products, but also as hydrodynamic separators and optical indicators of the reaction products during the purification process. We find that separation resolution is ultimately limited by the polydispersity in the mass of the gold nanoparticles and by structural distortions of DNA origami induced by the gold nanoparticles. Our study establishes a methodology for determining the design rules for nanomanufacturing DNA origami-nanoparticle constructs.

  15. 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

  16. 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

  17. 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

  18. 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.

  19. Preparative separation of sesamin and sesamolin from defatted sesame meal via centrifugal partition chromatography with consecutive sample injection.

    Science.gov (United States)

    Jeon, Je-Seung; Park, Chae Lee; Syed, Ahmed Shah; Kim, Young-Mi; Cho, Il Je; Kim, Chul Young

    2016-02-01

    A preparative separation method using consecutive sample injection centrifugal partition chromatography (CPC) was developed to obtain sesamin and sesamolin from defatted sesame meal extracts. A two-phase solvent system consisting of n-hexane-ethyl acetate-methanol-water (8:2:8:2, v/v) was applied in reversed-phase mode (descending mode). Preliminary experiments with an SCPC-100 (column volume: 100mL) were performed to select the appropriate two-phase solvent system and sample injection times; these parameters were then used with an SCPC-1000 (column volume: 1000mL) in a 10-fold scale-up preparative run. A sample containing 3g of crude extract was consecutively injected four times onto the SCPC-1000, which yielded 328mg of sesamin and 168mg of sesamolin. These compounds were analyzed by high-performance liquid chromatography and determined to have purities of 95.6% and 93.9%, respectively. Sesamin and sesamolin (30μM) increased antioxidant response element (ARE) luciferase activity 2.6-fold and 1.9-fold, respectively.

  20. 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.

  1. 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.

  2. Intensified Separation of Steviol Glycosides from a Crude Aqueous Extract of Stevia rebaudiana Leaves Using Centrifugal Partition Chromatography.

    Science.gov (United States)

    Hubert, Jane; Borie, Nicolas; Chollet, Sébastien; Perret, Joël; Barbet-Massin, Claire; Berger, Monique; Daydé, Jean; Renault, Jean-Hugues

    2015-11-01

    Aqueous extracts of Stevia rebaudiana leaves have been approved since 2008 by the Joint Expert Committee for Food Additives as sugar substitutes in many food and beverages in Western and Far East Asian countries. The compounds responsible for the natural sweetness of Stevia leaves include a diversity of diterpenoid glycosides derived from a steviol skeleton. These steviol glycosides also exhibit a low calorific value as well as promising therapeutic applications, particularly for the treatment of sugar metabolism disturbances. In this work, centrifugal partition chromatography is proposed as an efficient technical alternative to purify steviol glycosides from crude aqueous extracts of Stevia leaves on a multigram scale. Two different commercial instruments, including an ASCPC250® and a FCPE300® made of columns containing 1890 and 231 twin-cells, respectively, were evaluated and compared. All experiments were performed with a polar biphasic solvent system composed of ethyl acetate, n-butanol, and water in a gradient elution mode. When using the 1890 partition cell centrifugal partition chromatography column of 250 mL, 42 mg of stevioside, 68 mg of dulcoside A, and 172 mg of rebaudioside A, three major constituents of the initial extract were obtained from 1 g of the initial mixture at purities of 81%, 83%, and 99%, respectively. The productivity was further improved by intensifying the procedure on the 231 partition cell centrifugal partition chromatography column of 303 mL with the sample mass loading increased up to 5 g, resulting in the recovery of 1.2 g of stevioside, 100 mg of dulcoside A, and 1.1 g of rebaudioside A at purities of 79%, 62%, and 98%, respectively. The structures of the isolated compounds were validated by HPLC-UV, ESI-MS, (1)H, and (13)C NMR analyses. Altogether, the results demonstrate that the column design (i.e., the partition cell number) is an important aspect to be considered for a larger scale centrifugal partition chromatography

  3. Recovery Behavior of Separating Britholite (Ca3Ce2[(Si,P)O4]3F) Phase from Rare-Earth-rich Slag by Centrifugal Casting

    Science.gov (United States)

    Li, Juncheng; Guo, Zhancheng; Yang, Tao; Yue, Zicheng; Ma, Changhao

    2015-05-01

    A new approach to separate britholite phase from the rare-earth-rich slag by super gravity was investigated. With the parameter of G = 500, t = 5 min, T = 1423 K, almost all britholite phase is enriched in the concentrate, while the tailing is made up of CaF2 phase. Under the hypothesis that the RE exists in the slag in terms of RE2O3, with the gravity coefficient G = 500, t = 5 min and T = 1423 K, the mass fraction of RE2O3 in the concentrate is up to 24.67%, while the mass fraction of CaF2 in the tailing is 50.01%. Considering that the mass fraction of RE2O3 is 12.01% in the parallel sample, the recovery ratio of rare earth in the concentrate is up to 76.47% by centrifugal separation.

  4. 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

  5. Photochemical Synthesis and Versatile Functionalization Method of a Robust Porous Poly(ethylene glycol methacrylate-co-allyl methacrylate Monolith Dedicated to Radiochemical Separation in a Centrifugal Microfluidic Platform

    Directory of Open Access Journals (Sweden)

    Marion Losno

    2016-03-01

    Full Text Available The use of a centrifugal microfluidic platform is an alternative to classical chromatographic procedures for radiochemistry. An ion-exchange support with respect to the in situ light-addressable process of elaboration is specifically designed to be incorporated as a radiochemical sample preparation module in centrifugal microsystem devices. This paper presents a systematic study of the synthesis of the polymeric porous monolith poly(ethylene glycol methacrylate-co-allyl methacrylate used as a solid-phase support and the versatile and robust photografting process of the monolith based on thiol-ene click chemistry. The polymerization reaction is investigated, varying the formulation of the polymerisable mixture. The robustness of the stationary phase was tested in concentrated nitric acid. Thanks to their unique “easy-to-use” features, centrifugal microfluidic platforms are potential successful candidates for the downscaling of chromatographic separation of radioactive samples (automation, multiplexing, easy integration in glove-boxes environment, and low cost of maintenance.

  6. 微灌离心分离器内部流场分布数值模拟%Numerical simulation of flow field distribution in centrifugal separator for micro-irrigation

    Institute of Scientific and Technical Information of China (English)

    邱元锋; 孟戈; 罗金耀

    2015-01-01

    在缺水地区,利用高含沙水作为微灌水源的条件下,低浓度混合多相流模型已不能适用于微灌用离心分离器的数值模拟。该文以高含沙水作为微灌水源,结合离心分离器的结构参数,在流体力学基本方程基础上,通过网格划分和边界条件设定,采用有限体积法进行离散和求解,控制方程采用k-ε模型模拟分析了离心分离器的内部流场特征,并通过试验验证数值模拟成果,模拟值与试验实测值相对误差在10%以内,说明数值模拟采用的算法和模型是合理的。在试验验证的基础上,模拟分析了高含沙水为微灌水源的条件下,离心分离器的速度、湍动能以及静压分布,结果表明:离心分离器内速度分布主要有切向速度、轴向速度和径向速度,沿径向方向具有一定的对称性;离心分离器内湍动能分布具有一定的对称性,由轴中间向器壁两侧逐渐变小;静压分布具有一定的对称性性,由器壁两侧向轴中心逐渐减少。结果可为微灌用离心分离器特性参数的优化提供依据。%Centrifugal separator is one kind of filtration equipment that can separate the sediment from high-silt content water based on principles of rotational flow and centrifugal force. In recent years, research on numerical simulation of centrifugal separator is mostly in the fields of petroleum and chemical industry, and focuses on low concentration and mixture multiphase flow model. When using high-silt content water as micro-irrigation water source in water shortage areas, there will be high-silt content water near the centrifugal separator wall and underflow, in such case, low concentration and mixture multiphase flow model is not applicable to the numerical simulation of centrifugal separator that has used for micro-irrigation. Using high-silt content water as micro-irrigation water source, combined with the structure parameters of

  7. Factors Influencing the Separation Efficiency of Disc Centrifuge for Natural Latex%天然胶乳碟式离心机分离效率的影响因素

    Institute of Scientific and Technical Information of China (English)

    杨耀华; 李宗良

    2014-01-01

    The working principle of the disc centrifuge model LX-460 for separation of natural latex was brielfy introduced. The factors inlfuencing the separation efifciency such as regulator combination, separation time, solid content of fresh latex and centrifuge type were studied. The experimental results showed that there was an optimum length for the regulator screw when the separation efifciency was high. The efifciency could be reduced when the time was prolonged or the solid content of the latex increased. The centrifuge type also had an inlfuence on the separation efifciency. In order to improve the efifciency, it was recommended to establish standard processing parameters and separation time, control the quality of fresh latex, maintain the centrifuge in good condition, and strengthen personnel training.%简述LX-460型天然胶乳碟式离心机的工作原理,考察离心机调节器组合、分离时间、新鲜胶乳干胶浓度、离心机型号对天然胶乳离心分离效率的影响。结果表明:调节螺丝长度适当,分离效率较高;分离时间延长,分离效率降低;新鲜胶乳干胶含量越大,分离效率降低;离心机型号对分离效果有一定的影响。确定合理的工艺参数和分离时间、控制新鲜胶乳质量、良好维护离心机、加强操作人员培训是提高离心机分离效率的重要措施。

  8. Evaluation of real-time PCR coupled with immunomagnetic separation or centrifugation for the detection of healthy and sanitizer-injured Salmonella spp. on mung bean sprouts.

    Science.gov (United States)

    Zheng, Qianwang; Mikš-Krajnik, Marta; Yang, Yishan; Lee, Sang-Myun; Lee, Seung-Cheol; Yuk, Hyun-Gyun

    2016-04-02

    Fresh mung bean sprouts have been identified as a source of many Salmonella outbreaks worldwide. The aim of this study was to develop a rapid and accurate detection methodology for low levels of healthy and sanitizer-injured Salmonella on mung bean sprouts using real-time PCR coupled with either immunomagnetic separation (PCR-IMS) or centrifugation (PCR-cen). Initially, three parameters of IMS; specificity/sensitivity, bacterial concentration and bead incubation time were optimized. Secondly, limit of detection (LOD) was determined for the optimized PCR-IMS and PCR-cen. These two methods were compared against PCR alone (PCR) and the standard culture method (ISO) for their ability to detect Salmonella using inoculated and uninoculated sprouts. Under optimum IMS conditions (10(5)CFU/ml for 30 min), capture efficiency of Salmonella in sprout suspensions was lower than 40%, most probably due to the non-specific binding of the background microbiota. PCR-IMS and PCR-cen had a similar LOD at 10(3)CFU/ml, which was one log unit lower than PCR. Enrichment of 10h was sufficient to detect 100% of the inoculated sprouts with both PCR-IMS and PCR-cen, which was significantly faster compared to PCR and the ISO method. Moreover, the validation study using uninoculated sprouts revealed that PCR-IMS and PCR-cen were equally effective on Salmonella detection, showing 98.3% accuracy. These results suggest that PCR-cen would be the effective and less costly method for the detection of both healthy and sanitizer-injured Salmonella on mung bean sprouts.

  9. 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...

  10. 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...

  11. 钻井污水处理装置离心分离橇的试验研究%Experimental Study of the Centrifugal Separation Skid of Sewage Treatment Unit

    Institute of Scientific and Technical Information of China (English)

    李向伟; 许福东; 李海明; 鄢玲俐; 杨迅; 杨晓峰; 伍远平

    2013-01-01

    An industrial test of the centrifugal separation skid on drilling wastewater treatment unit was conducted. The operating mechanism and efficiency of the treatment components of the unit were discussed. The operating parameters of the horizontal decanter centrifuge as the key treatment component of the skid were optimized through test. The flocculating agent was screened. The field test shows that the operating parameters suitable for the decanter centrifuge in treatment of drilling wastewater are large length-diameter ratio, high overflow weir plate, separation factor 1 314-1 716, and differential speed 5~12 r/min. The skid adopts the wastewater treatment technology of de-oiling buffering, centrifugal separation and adsorption filtration. The turbidity of the water at the outlet reaches 20 NTU below. The chromaticity decreases remarkably. It can satisfy the recycling requirement for mud preparation and mud replacement after drilling completion. It can also be used as inflow of standard discharge treatment equipment. The treatment technology is characterized by compact structure, easy transportation, and few manual operations. It is suitable for the operating condition of drilling crews.%对钻井污水处理装置离心分离橇进行了工业性试验研究,探讨了各处理单元的工作机理和功效,对分离橇的核心处理单元卧螺离心机的工作参数进行了试验优化,对絮凝剂进行了筛选.现场试验结果表明,卧螺离心机适合处理钻井污水的工作参数范围为大长径比、高溢流堰板、分离因数1 314~1 716、差转速5~ 12 r/min;离心分离橇采用除油缓冲→离心分离→吸附过滤工艺处理钻井污水,出水浊度达到20 NTU以下,色度明显降低,能够达到配钻井液和完钻后的替换钻井液等回用要求,也可作为达标排放处理设备的进水.该处理工艺具有设备结构紧凑,便于移运,人工参与少,能连续运行的特点,适合钻井队的使用工况.

  12. 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

  13. 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.

  14. 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.

  15. 卧螺式浮渣分离离心机两相数值模拟%Two-phase numerical simulation research in a decanter centrifuge of separating floating sludge

    Institute of Scientific and Technical Information of China (English)

    朱明军; 袁惠新; 付双成; 董连东

    2015-01-01

    Traditional decanter centrifuge is only used to separate heavy sludge rather than floating sludge. This research developed a two-phase numerical simulation on a decanter centrifuge in separating light solid floating sludge. The three dimension software Pro-E was used to build the 3D model. The computational fluid dynamics software Fluent was applied to analyze volume fraction distribution of the solid and liquid phase as well as the effects of operating conditions and fluid parameters on flow field and separation properties. The simulation was based on Euler multiple phase flow model and RNGk-εturbulence model in a multiple coordinate reference system. The simulation results showed that the decanter centrifuge can be used to separate high density and middle-coarse particles;the fluid settling lamination was obvious and water was in the inner side while floating sludge outside of cistern;there was little effect of rotation speed discrepancy on separation properties. Rotation speed discrepancy in the range of 30—70r/min was optimal. With the increase of the feed concentration,particles’ setting velocity and separation efficiency decreased. Low setting velocity for small particles resulted in less separation efficiency and coarse particles had higher separation capabilities because of quick setting velocity.%传统的卧式螺旋卸料离心机只能分离沉渣,不能分离浮渣。本文对一种分离轻质固体浮渣的卧螺离心机进行两相数值模拟研究,使用Pro-E软件建立三维模型,应用计算流体力学软件Fluent,基于Euler多相流模型,采用RNG k-ε湍流模型及多重参考系(MRF)方法,模拟分析了这种卧螺离心机内的固液两相体积分数分布以及操作参数和物性参数对流场和分离性能的影响。模拟结果表明:此卧螺离心机适用于高浓度、中粗粒子的分离;流体沉降分层比较明显,水在液池的外层,浮渣在内层;转速差总体上对分离性

  16. Detection of outliers by neural network on the gas centrifuge experimental data of isotopic separation process; Aplicacao de redes neurais para deteccao de erros grosseiros em dados de processo de separacao de isotopos de uranio por ultracentrifugacao

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Monica de Carvalho Vasconcelos

    2004-07-01

    This work presents and discusses the neural network technique aiming at the detection of outliers on a set of gas centrifuge isotope separation experimental data. In order to evaluate the application of this new technique, the result obtained of the detection is compared to the result of the statistical analysis combined with the cluster analysis. This method for the detection of outliers presents a considerable potential in the field of data analysis and it is at the same time easier and faster to use and requests very less knowledge of the physics involved in the process. This work established a procedure for detecting experiments which are suspect to contain gross errors inside a data set where the usual techniques for identification of these errors cannot be applied or its use/demands an excessively long work. (author)

  17. 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.

  18. 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...

  19. 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.

  20. 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.

  1. 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

  2. Design of a coil satellite centrifuge and its performance on counter-current chromatographic separation of 4-methylumbelliferyl sugar derivatives with polar organic-aqueous two-phase solvent systems.

    Science.gov (United States)

    Shinomiya, Kazufusa; Tokura, Koji; Kimura, Emiru; Takai, Midori; Harikai, Naoki; Yoshida, Kazunori; Yanagidaira, Kazuhiro; Ito, Yoichiro

    2015-05-01

    A new high-speed counter-current chromatograph, named coil satellite centrifuge (CSC), was designed and fabricated in our laboratory. The CSC apparatus produces the satellite motion such that the coiled column simultaneously rotates around the sun axis (the angular velocity, ω1), the planet axis (ω2) and the satellite axis (the central axis of the column) (ω3). In order to achieve this triplicate rotary motion without twisting of the flow tube, the rotation of each axis was determined by the following formula: ω1=ω2+ω3. This relation enabled to lay out the flow tube without twisting by the simultaneous rotation of three axes. The flow tube was introduced from the bottom side of the apparatus into the sun axis of the first rotary frame reaching the upper side of the planet axis and connected to the column in the satellite axis. The performance of the apparatus was examined on separation of 4-methylumbelliferyl (MU) sugar derivatives as test samples with organic-aqueous two-phase solvent systems composed of ethyl acetate/1-butanol/water (3:2:5, v/v) for lower phase mobile and (1:4:5, v/v) for upper phase mobile. With lower phase mobile, five 4-MU sugar derivatives including β-D-cellobioside (Cel), β-D-glucopyranoside, α-D-mannopyranoside, β-D-fucopyranoside and α-L-fucopyranoside (α-L-Fuc) were separated with the combined rotation around each axis at counterclockwise (CCW) (ω1) - CCW (ω2) - CCW (ω3) by the flow tube distribution. With upper phase mobile, three 4-MU sugar derivatives including α-L-Fuc, β-D-galactopyranoside and Cel were separated with the combined rotation around each axis at clockwise (CW) (ω1) - CW (ω2) - CW (ω3) by the flow tube distribution. A series of experiments on peak resolution and stationary phase retention revealed that better partition efficiencies were obtained at the flow rate of 0.5 mL/min (column 1) and 0.8 mL/min (column 2) for lower phase mobile and 0.2 mL/min (column 1) and 0.4 mL/min (column 2) for upper phase

  3. 21 CFR 864.9275 - Blood bank centrifuge for in vitro diagnostic use.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Blood bank centrifuge for in vitro diagnostic use... Manufacture Blood and Blood Products § 864.9275 Blood bank centrifuge for in vitro diagnostic use. (a) Identification. A blood bank centrifuge for in vitro diagnostic use is a device used only to separate blood...

  4. 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....

  5. 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.

  6. 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.

  7. Comparison of the peak resolution and the stationary phase retention between the satellite and the planetary motions using the coil satellite centrifuge with counter-current chromatographic separation of 4-methylumbelliferyl sugar derivatives.

    Science.gov (United States)

    Shinomiya, Kazufusa; Zaima, Kazumasa; Harada, Yukina; Yasue, Miho; Harikai, Naoki; Tokura, Koji; Ito, Yoichiro

    2017-01-20

    Coil satellite centrifuge (CSC) produces the complex satellite motion consisting of the triplicate rotation of the coiled column around three axes including the sun axis (the angular velocity, ω1), the planet axis (ω2) and the satellite axis (the central axis of the column) (ω3) according to the following formula: ω1=ω2+ω3. Improved peak resolution in the separation of 4-methylumbelliferyl sugar derivatives was achieved using the conventional multilayer coiled columns with ethyl acetate/1-butanol/water (3: 2: 5, v/v) for the lower mobile phase at the combination of the rotation speeds (ω1, ω2, ω3)=(300, 150, 150rpm), and (1:4:5, v/v) for the upper mobile phase at (300:100:200rpm). The effect of the satellite motion on the peak resolution and the stationary phase retention was evaluated by each CSC separation with the different rotation speeds of ω2 and ω3 under the constant revolution speed at ω1=300rpm. With the lower mobile phase, almost constant peak resolution and stationary phase retention were yielded regardless of the change of ω2 and ω3, while with the upper mobile phase these two values were sensitively varied according to the different combination of ω2 and ω3. For example, when ω2=147 or 200rpm is used, no stationary phase was retained in the coiled column while ω2=150rpm could retain enough volume of stationary phase for separation. On the other hand, the combined rotation speeds at (ω1, ω2, ω3)=(300, 300, 0rpm) or (300, 0, 300rpm) produced insufficient peak resolution regardless of the choice of the mobile phase apparently due to the lack of rotation speed except at (300, 0, 300rpm) with the upper mobile phase. At lower rotation speed of ω1=300rpm, better peak resolution and stationary phase retention were obtained by the satellite motion (ω3) than by the planetary motion (ω2), or ω3>ω2. The effect of the hydrophobicity of the two-phase solvent systems on the stationary phase retention was further examined using the n

  8. 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.

  9. 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

  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. 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

  12. 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.)

  13. 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.

  14. 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.

  15. On the progress in stable isotope separation

    Energy Technology Data Exchange (ETDEWEB)

    Prusakov, V.N. [Kurchatov Institute, Moscow (Russian Federation)

    1994-12-31

    The principles and process of centrifuge isotope separation are reviewed; the fundamental advantage of the centrifuge over gaseous diffusion arises from the fact that the primary isotope separation effect occurs at thermodynamic equilibrium; thus, gas centrifuge enrichment uses only about 1/20 to 1/30 of the electricity per SWU (separation work unit) consumed by gaseous diffusion. The various substances that can be used in centrifuge isotope separation are listed (fluorides, oxyfluorides, {pi}-complexes, boron hydrides, metal-organic compounds, halides...). The centrifuge method productivity is much greater than with the electromagnetic separation technique; examples of centrifuge stable and radioactive isotope separation are given; the method of the residue reduction is also presented with the example of separating radioactive krypton-85 out of a nuclear reactor krypton blend. 4 figs.

  16. Topological analysis of the formation of Jet-Wake flow pattern in centrifugal impeller channel

    Institute of Scientific and Technical Information of China (English)

    ZHENG Qun; LIU Shun-long

    2004-01-01

    Topological analyses are carried out for the numerical results of internal flow field in centrifugal impeller. Topological rules of the singular point characteristics of the limiting streamline are derived and used to determine three dimensional separation patterns in centrifugal impeller and to verify the numerical results. The results reveal that the wake is saddle to nodal closed separation and the formation, its onset point and its developing process of Jet-Wake Flow pattern in centrifugal impeller are presented in this paper.

  17. 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...

  18. 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.

  19. 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.

  20. 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.

  1. Centripetal/Centrifugal Family Style of Families with Aggressive and Non-Aggressive Boys.

    Science.gov (United States)

    Hurst, Duane F.; And Others

    Research on family interaction has characterized family style on centripetal and centrifugal dimensions, representing opposing natures with their own continua. Centripetal forces produce binding, or a prolonged process of separation of parent and child; centrifugal forces preciptate expelling, or hastened separation and premature autonomy. To…

  2. 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).

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. [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.

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. German chemical plants with particular reference to centrifuges

    Energy Technology Data Exchange (ETDEWEB)

    Broadbent, F.

    1946-01-01

    This report consisted of 9 reports. Report No. 1 was about Elmore Metall A. G., Schlandern on Siegburg. Two divisions of works in this factory were: (1) tube-drawing section for copper, steel, and zinc, with old machinery; (2) a section making electrolytically-deposited copper cylinders up to 100'' diameter, of high purity and excellent mechanical properties. The electrolytically-deposited copper cylinders were produced in lead-lined wooden tanks. Report No. 2 was about H. Krantz Maschinenfabrik, Aachen. This firm specialized in hydro-extractors, confined to types suitable for laundries and textile work. The machines built were of sizes from 800 mm to 1,8000 mm basket diameter. Report No. 3 was about O. Doerries A. G., Vorm Banning, and Seyfold Duren. This firm specialized in paper-making machinery, including centrifugal grit extractors for the treatment of paper stock. Erkensators number 4 and number 4L were compared in this report. Reports No. 4 and No. 5 were about I. G. Farbenindustrie, Dormagen, and Elberfeld. General information about the continuously-operating centrifuges was given. Report No. 6 was about Glanstoff Courtald between Cologne and Dormagen, where they used two methods of extracting water from viscose cakes, (1) by multiple-hinged candle hydro-extractors, and (2) by converted spinning pots. Report No. 7 was about Matthers and Weber, Duisberg, and gave general information about two kinds of centrifuges, (1) for crude bi-carbonate, and (2) for refined bi-carbonate. Report No. 8 was about Westfalia Separator A. G., Oelde; where the high-speed centrifuges of the ''cream separator'' or Laval type were made. Report No. 9 was about Escher Wyss, Ravensburg, where centrifuges, water turbines, spray dryers, and paper-making machinery were manufactured.

  19. Effect of gelatin on the water dispersion and centrifugal purification of single-walled carbon nanotubes

    Science.gov (United States)

    Hanium Maria, Kazi; Mieno, Tetsu

    2016-01-01

    We report a convenient and effective procedure for the water dispersion and purification of single-walled carbon nanotubes (SWNTs). The purification procedure involves a combination of dispersion and centrifugation, in which gelatin; an environmentally friendly material is used as a dispersing agent. It has been found that an aqueous solution of gelatin effectively disperses SWNTs for more than a month. Another advantage of using gelatin as a dispersing agent is that it can be easily removed by washing with water and filtration. The centrifugation procedure employs a centrifugal force of about 2500 times the gravitational force to separate the particles. Although carbonaceous and metallic impurities usually have higher density than SWNTs in arc-produced carbon soot, the centrifugation can easily remove impurities leaving undamaged SWNTs in solution when appropriate centrifugal force and a centrifugation time are used. Centrifugation is carried out for three times to sufficiently remove impurities. Finally, the SWNTs are separated from the gelatin by heating in water and filtering.

  20. Dynamical system analysis of unstable flow phenomena in centrifugal blower

    Directory of Open Access Journals (Sweden)

    Garcia David

    2015-09-01

    Full Text Available Methods of dynamical system analysis were employed to analyze unsteady phenomena in a centrifugal blower. Pressure signals gathered at different control points were decomposed into their Principal Components (PCs by means of Singular Spectrum Analysis (SSA. Certain number of PCs was considered in the analysis based on their statistical correlation. Projection of the original signal onto its PCs allowed to draw the phase trajectory that clearly separated non-stable blower working conditions from its regular operation.

  1. 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.

  2. 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

    measured at design flow rate and speed. The measured efficiency and stall margin were lower than pre-test CFD predictions by 2.4 percentage points (pt) and 4.5 pt, respectively. Initial impressions from the experimental data indicated that the loss in the efficiency and stall margin can be attributed to a design shortfall in the impeller. However, detailed investigation of experimental data and post-test CFD simulations of higher fidelity than pre-test CFD, and in particular the unsteady CFD simulations and the assessment with a wider range of turbulence models, have indicated that the loss in efficiency is most likely due to the impact of unfavorable unsteady impeller/diffuser interactions induced by diffuser vanes, an impeller/diffuser corrected flow-rate mismatch (and associated incidence levels), and, potentially, flow separation in the radial-to-axial bend. An experimental program with a vaneless diffuser is recommended to evaluate this observation. A subsequent redesign of the diffuser (and the radial-to-axial bend) is also recommended. The diffuser needs to be redesigned to eliminate the mismatching of the impeller and the diffuser, targeting a slightly higher flow capacity. Furthermore, diffuser vanes need to be adjusted to align the incidence angles, to optimize the splitter vane location (both radially and circumferentially), and to minimize the unsteady interactions with the impeller. The radial-to-axial bend needs to be redesigned to eliminate, or at least minimize, the flow separation at the inner wall, and its impact on the flow in the diffuser upstream. Lessons were also learned in terms of CFD methodology and the importance of unsteady CFD simulations for centrifugal compressors was highlighted. Inconsistencies in the implementation of a widely used two-equation turbulence model were identified and corrections are recommended. It was also observed that unsteady simulations for centrifugal compressors require significantly longer integration times than what

  3. Separation of carbon nanotubes into chirally enriched fractions

    Science.gov (United States)

    Doorn, Stephen K [Los Alamos, NM; Niyogi, Sandip [Los Alamos, NM

    2012-04-10

    A mixture of single-walled carbon nanotubes ("SWNTs") is separated into fractions of enriched chirality by preparing an aqueous suspension of a mixture of SWNTs and a surfactant, injecting a portion of the suspension on a column of separation medium having a density gradient, and centrifuging the column. In some embodiments, salt is added prior to centrifugation. In other embodiments, the centrifugation is performed at a temperature below room temperature. Fractions separate as colored bands in the column. The diameter of the separated SWNTs decreases with increasing density along the gradient of the column. The colored bands can be withdrawn separately from the column.

  4. 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....

  5. 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.

  6. 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.

  7. Low-molecular weight plasma proteome analysis using centrifugal ultrafiltration.

    Science.gov (United States)

    Greening, David W; Simpson, Richard J

    2011-01-01

    The low-molecular weight fraction (LMF) of the human plasma proteome is an invaluable source of biological information, especially in the context of identifying plasma-based biomarkers of disease. This protocol outlines a standardized procedure for the rapid/reproducible LMF profiling of human plasma samples using centrifugal ultrafiltration fractionation, followed by 1D-SDS-PAGE separation and nano-LC-MS/MS. Ultrafiltration is a convective process that uses anisotropic semipermeable membranes to separate macromolecular species on the basis of size. We have optimized centrifugal ultrafiltration for plasma fractionation with respect to buffer and solvent composition, centrifugal force, duration and temperature to facilitate >95% recovery, and enrichment of low-M (r) components from human plasma. Using this protocol, >260 unique peptides can be identified from a single plasma profiling experiment using 100 μL of plasma (Greening and Simpson, J Proteomics 73:637-648, 2010). The efficacy of this method is demonstrated by the identification, for the first time, of several plasma proteins (e.g., protein KIAA0649 (Q9Y4D3), rheumatoid factor D5, serine protease inhibitor A3, and transmembrane adapter protein PAG) previously not reported in extant high-confidence Human Proteome Organization Plasma Proteome Project datasets.

  8. 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

  9. 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 ...

  10. 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.

  11. Methodology for optimally sized centrifugal partition chromatography columns.

    Science.gov (United States)

    Chollet, Sébastien; Marchal, Luc; Jérémy Meucci; Renault, Jean-Hugues; Legrand, Jack; Foucault, Alain

    2015-04-01

    Centrifugal Partition Chromatography (CPC) is a separation process based on the partitioning of solutes between two partially miscible liquid phases. There is no solid support for the stationary phase. The centrifugal acceleration is responsible for both stationary phase retention and mobile phase dispersion. CPC is thus a process based on liquid-liquid mass transfer. The separation efficiency is mainly influenced by the hydrodynamics of the phases in each cell of the column. Thanks to a visualization system, called "Visual CPC", it was observed that the mobile phase can flow through the stationary phase as a sheet, or a spray. Hydrodynamics, which directly governs the instrument efficiency, is directly affected during scale changes, and non-linear phenomena prevent the successful achievement of mastered geometrical scale changes. In this work, a methodology for CPC column sizing is proposed, based on the characterization of the efficiency of advanced cell shapes, taking into account the hydrodynamics. Knowledge about relationship between stationary phase volume, cell efficiency and separation resolution in CPC allowed calculating the optimum cell number for laboratory and industrial scale CPC application. The methodology is highlighted with results on five different geometries from 25 to 5000 mL, for two applications: the separation of alkylbenzene by partitioning with heptane/methanol/water biphasic system; and the separation of peptides by partitioning with n-butanol/acetic acid/water (4/1/5) biphasic system. With this approach, it is possible to predict the optimal CPC column length leading to highest productivity.

  12. 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...

  13. 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.

  14. 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....

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  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. 21 CFR 864.9245 - Automated blood cell separator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Automated blood cell separator. 864.9245 Section... Blood and Blood Products § 864.9245 Automated blood cell separator. (a) Identification. An automated blood cell separator is a device that uses a centrifugal or filtration separation principle...

  5. The application of two-dimensional centrifugation to clinical chemistry testing.

    Science.gov (United States)

    Holen, J T; Schultz, S G; Wong, S T

    1986-01-01

    We have developed a new clinical chemistry analyzer, the VISION System, which uses centrifugal force to separate whole blood, measure reagent and plasma volumes, and complete all steps required for a spectrophotometric analysis. The system is based on a multichambered test pack containing liquid reagents, which can be centrifuged in two planes oriented at right angles to each other. The analyzer regulates the temperature, timing and optical measurements for up to 10 different test packs in the same run. We have demonstrated good precision and accuracy on 6 clinical chemistry analytes, 2 enzymes, potassium and theophylline using this system.

  6. Uranium enrichment using gas centrifugation. An analysis focusing export control; Urananrikning med gascentrifugering. En analys med fokus paa exportkontroll

    Energy Technology Data Exchange (ETDEWEB)

    Oliver, Lena; Peterson, Jenny; Wilhelmsen, Katarina [Swedish Defense Research Inst., Stockholm (Sweden)

    2005-08-01

    The Swedish Defence Research Agency, FOI, has performed a study on uranium enrichment by gas centrifugation. The theory and principles of gas centrifugation is described in this report and relevant equipment used in the process has been identified. Different aspects of operating a gas centrifuge facility - and its indicators - are also presented. The separation efficiency and the flow of material through a centrifuge are very small, and therefore, a large number of centrifuges in cascades is needed to produce a larger amount of enriched uranium within a reasonable time. Countries with nuclear weapons ambitions often show an interest in gas centrifuges to produce weapons grade uranium - if they have managed to acquire the technology - because of the efficiency of the process and since it is relatively easy to conceal. Most equipment used in gas centrifuge facilities is under export control to prevent clandestine uranium enrichment. The Nuclear Suppliers' Group has compiled lists of nuclear related equipment and components that are of importance to export control. The control lists have also been included in the EU legislation.

  7. 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.

  8. Clinical use of centrifugal pumps and the roller pump in open heart surgery: a comparative evaluation.

    Science.gov (United States)

    Yoshikai, M; Hamada, M; Takarabe, K; Okazaki, Y; Ito, T

    1996-06-01

    Centrifugal pumps have been used widely as the main pump in open heart surgery to reduce damage to blood elements and to reduce the activation of the coagulation system. The purpose of this study was the evaluation and comparison of the effects of two types of centrifugal pumps and of one type of roller pump on blood elements, the coagulation system, complements, and immunoglobulins. Two types of centrifugal pumps (Lifestream; St. Jude Medical, Chelmsford, Massachusetts; and BP-80: Medtronic, BioMedicus, Inc., Eden Prairie, Minnesota, U.S.A.) and one roller pump (Mera Co.) were used separately as the main pump for cardiopulmonary bypass (CPB) in 29 patients. Platelet counts, lactate dehydrogenase, antithrombin III, thrombin-antithrombin complex (TAT), complements (C3, C4, and CH50) and immunoglobulins G, A, and M values were measured before and after CPB and compared. Values, except those for TAT, showed no significant difference among the three groups. The TAT values increased less in each of the centrifugal pump groups than in the roller pump group. This finding suggests that thrombin synthesis might be suppressed by the use of a centrifugal pump.

  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. Different Ways to On-Line Hyphenate Centrifugal Partition Chromatography and Mass Spectrometry: Application to Prenylated Xanthones from Garcinia mangostana.

    Science.gov (United States)

    Destandau, Emilie; Michel, Thomas; Toribio, Alix; Elfakir, Claire

    2015-11-01

    Centrifugal partition chromatography is a liquid-liquid separation method well adapted for the fractionation or purification of natural compounds from plant extracts. However, following the preparative isolation, the fractions collected must be analysed by high-performance thin-layer chromatography or high-performance liquid chromatography to evaluate their composition and/or their purity. These additional steps are time-consuming and increase the risk of compound degradation. In order to get an instantaneous analysis of fraction content with structural information on the phytochemicals eluted, it is possible to hyphenate on-line centrifugal partition chromatography with mass spectrometry. Depending on the complexity of the extract, two different kinds of centrifugal partition chromatography-mass spectrometry coupling can be performed: centrifugal partition chromatography-mass spectrometry or centrifugal partition chromatography-high-performance liquid chromatography-mass spectrometry coupling. In the first case, one part of the centrifugal partition chromatography effluent is directly introduced in the mass spectrometry ionisation source to identify the eluted compounds, while in the second case, it is directed to a high-performance liquid chromatography-mass spectrometry system where compounds are first separated thanks to high-performance liquid chromatography and then identified using mass spectrometry.

  11. The trend of stable isotope separation

    Energy Technology Data Exchange (ETDEWEB)

    Yonekawa, Shigeru [Power Reactor and Nuclear Fuel Development Corp., Kamisaibara, Okayama (Japan). Ningyo Toge Works; Aoki, Eiji; Yato, Yumio

    1994-12-01

    Recently, stable isotopes are used in the field of medical science, nuclear physics, environmental science and agriculture. This report reviews the present status of stable isotope enrichment in ORNL, Urenco, Russia and PNC. Further the utilization method of the stable isotopes in the field of medical science, nuclear power and material science are described, and the application possibility of Laser separation method and Gas Centrifuge method are estimated. There are many overseas actual results of stable isotope separation with Gas Centrifuge method, therefore this method is possible enough in principle. (author).

  12. Flow Characteristics of a Pipe Diffuser for Centrifugal Compressors

    Directory of Open Access Journals (Sweden)

    Zhenzhong Sun

    2017-01-01

    Full Text Available The pipe diffuser, an efficient kind of radial bladed diffuser, is widely used in centrifugal compressors for gas turbine engines. This paper investigates flow characteristics of a pipe diffuser for centrifugal compressors by solving three-dimensional Reynolds-averaged Navier-Stokes equations. The results show that the pipe diffuser is adaptable to high Mach number incoming flows, and its unique leading edge could uniform the flow distortion. Numerical analysis indicates that the choke in pipe diffuser occurs suddenly, which leads to the dramatically steep performance curves near choke condition. Besides, it is found that the first half flow passage is particularly important to the pipe diffuser performance as it influences the choking behavior, the static pressure distribution, and the matching, so more attention should be paid to this region when designing or optimizing a pipe diffuser. Two counter-rotating vortices generated in the diffuser inlet region are captured by numerical simulation, and they can exist in the downstream of the diffuser passage. More detailed analysis show that these two vortices dominate the flow structure in the whole diffuser passage by shifting flow to certain positions and forming high-momentum flow cells and wake flow cells. The leading edge formed by the intersection of adjacent diffuser passages significantly affects this pair of vortices. In addition, these two vortices also affect the flow separation in pipe diffuser flow passages, they suppress separation near the front wall and back wall while facilitate separation at center locations. Therefore, it is recommended to design the leading edge of the pipe diffuser carefully to control the vortices and obtain a better flow field.

  13. Experiments on Plasma Injection into a Centrifugally Confined System

    Science.gov (United States)

    Messer, S.; Bomgardner, R.; Brockington, S.; Case, A.; Witherspoon, F. D.; Uzun-Kaymak, I.; Elton, R.; Young, W.; Teodorescu, C.; Morales, C. H.; Ellis, R. F.

    2009-11-01

    We describe the cross-field injection of plasma into a centrifugally-confined system. Two different types of plasma railgun have been installed on the Maryland Centrifugal Experiment (MCX) in an attempt to drive that plasma's rotation. The initial gun was a coaxial device designed to mitigate the blowby instability. The second one was a MiniRailgun with a rectangular bore oriented so that the MCX magnetic field augments the railgun's internal magnetic field. Tests at HyperV indicate this MiniRailgun reaches much higher densities than the original gun, although muzzle velocity is slightly reduced. We discuss the impact of these guns on MCX for various conditions. Initial results show that even for a 2 kG field, firing the MiniRailgun modifies oscillations of the MCX diamagnetic loops and can impact the core current and voltage. The gun also has a noticeable impact on MCX microwave emissions. These observations suggest plasma enters the MCX system. We also compare diagnostic data collected separately from MCX for these and other guns, focussing primarily on magnetic measurements.

  14. Numerical modeling of centrifuge cyclic lateral pile load experiments

    Institute of Scientific and Technical Information of China (English)

    Nikos Gerolymos; Sandra Escoffer; George Gazetas; Jacques Gamier

    2009-01-01

    To gain insight into the inelastic behavior of piles, the response of a vertical pile embedded in dry sand and subjected to cyclic lateral loading was studied experimentally in centrifuge tests conducted in Laboratoire Central des Ponts et Chaussees. Three types of cyclic loading were applied, two asymmetric and one symmetric with respect to the unloaded pile. An approximately square-root variation of soil stiffness with depth was obtained from indirect in-flight density measurements, laboratory tests on reconstituted samples, and well-established empirical correlations. The tests were simulated using a cyclic nonlinear Winkler spring model, which describes the full range of inelastic phenomena, including separation and re-attachment of the pile from and to the soil. The model consists of three mathematical expressions capable of reproducing a wide variety of monotonic and cyclic experimental p-y curves. The physical meaning of key model parameters is graphically explained and related to soil behavior. Comparisons with the centrifuge test results demonstrate the general validity of the model and its ability to capture several features of pile-soil interaction, including: soil plastification at an early stage of loading, "pinching" behavior due to the formation of a relaxation zone around the upper part of the pile, and stiffness and strength changes due to cyclic loading. A comparison of the p-y curves derived from the test results and the proposed model, as well as those from the classical curves of Reese et al. (1974) for sand, is also presented.

  15. Thermal hydrodynamic analysis of a countercurrent gas centrifuge; Analise termo hidrodinamica de uma centrifuga a contracorrente

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Delvonei Alves de

    1999-07-01

    The influence of the thermal countercurrent on the separative performance of countercurrent centrifuges is treated in this work. The methodology used consists in modeling the gas flow inside the rotor under thermal boundary conditions supplied by the structural thermal model. The gas flow model, also called hydrodynamical model, is based on the Finite Volume Method for cylindrical geometry with azimuthal symmetry. The structural thermal model is based on the Nodal Method and take into account simultaneously, the conduction convection and radiation phenomena. The procedure adopted for this study consisted in the definition of the operational and geometric conditions of a centrifuge which was used as a pattern to the accomplished analysis. This configuration, called 'Standard Centrifuge', was used for the accomplishment of several simulations where the importance of the realistic boundary thermal conditions for the numerical evaluation of the centrifuge separative capacity was evidenced. A selective alteration for the optical properties based on simple engineering procedures was proposed. An improvement of 5% was obtained with this alteration. (author)

  16. 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…

  17. 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...

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. SEPARATION OF X-BEARING BOVINE SPERM BY CENTRIFUGATION IN CONTINUOUS PERCOLL AND OPTIPREP DENSITY GRADIENT: EFFECT IN SPERM VIABILITY AND IN VITRO EMBRYO PRODUCTION SEPARAÇÃO DE ESPERMATOZOIDES PORTADORES DO CROMOSSOMO X BOVINO POR CENTRIFUGAÇÃO EM GRADIENTE DE DENSIDADE CONTÍNUO DE PERCOLL E OPTIPREP: EFEITO SOBRE A VIABILIDADE ESPERMÁTICA E NA PRODUÇÃO IN VITRO DE EMBRIÕES

    Directory of Open Access Journals (Sweden)

    Aline Costa Lucio

    2009-07-01

    Full Text Available

    The aim of this study was to separate X-bearing bovine sperm by continuous Percoll and OptiPrep density gradients and to validate the sexing of resultant in vitro produced embryos by Polimerase Chain Reaction (PCR. Frozen/thawed sperm was layered on density gradients which were previously prepared in polystyrene tubes, 24 h before procedures and maintained at 4 °C. The tubes were centrifuged at 500 x g for 15 min at 22 °C. Supernatants were gently aspirated and the sperm recovered from the bottom of the tubes. Viability and integrity of sperm were evaluated by Trypan Blue/Giemsa stain. Cleavage and blastocyst rates were determined by in vitro production of embryos and PCR was performed for identification of the embryos’ genetic sex. No damage in viability and acrossomal integrity and in cleavage and blastocyst rates was found in the Percoll and OptiPrep treatment compared to the non-centrifuged group (P>0.05. The percentage of female embryos in the Percoll and OptiPrep group was 63.0 and 47.6%, respectively. The female embryos in control group were 48.7%. A sexual deviation in the Percoll density gradient was achieved without reduction of sperm viability and in vitro production rates.

    KEY WORDS: Bovine, centrifugation, in vitro production of embryos, PCR, X-bearing sperm.

    O objetivo deste estudo foi separar espermatozoides bovinos portadores do cromossomo X pela centrifugação em gradiente de densidade contínuo de Percoll e OptiPrep, e validar a sexagem pela reação em cadeia da polimerase (PCR, dos embriões produzidos in vitro. Para a sexagem, espermatozoides descongelados foram depositados nos gradientes de densidade, previamente preparados, em tubos de poliestireno, 24 horas antes da sexagem e mantidos a 4°C. Centrifugou-se a 500 x g por quinze minutos a 22°C. Os sobrenadantes foram aspirados, e os espermatozoides recuperados do

  4. Application of IMHOFLOT G-cell centrifugal flotation technology

    Energy Technology Data Exchange (ETDEWEB)

    Imhof, R.; Fletcher, M.; Vathavooran, A.; Singh, A. [Maelgwyn Mining Services Ltd., Cardiff (United Kingdom)

    2007-10-15

    The Imhoflot G-Cell, a new development in the pneumatic flotation technology (which incorporates centrifugal forces in the separating vessel), is a recent innovation in the mineral processing world. The G-Cell was invented by Dr Rainer Imhof and commercialized by Maelgwyn Mineral Services Ltd. In a short time span a number of plants and units have been successfully commissioned in the mineral processing industry. In addition, a number of industrial G-Cell flotation plants are in the process of construction for the purpose of coal preparation and environmental remediation. In this paper two industrial installations have been highlighted, together with a pilot plant test programme investigating ultra-fine flotation recovery for a base metal operation.

  5. Short communication. Stallion sperm quality after combined ejaculate fractionation and colloidal centrifugation

    Directory of Open Access Journals (Sweden)

    Francisco Crespo

    2015-12-01

    Full Text Available This study investigated the possible additive benefit of ejaculate fractionation and colloidal centrifugation on stallion sperm quality. Using an open-end artificial vagina, the sperm-rich fraction (FRAC-1 was separated from the rest of the ejaculate (FRAC-2 and a third sperm sample representing the combined ejaculate was reconstituted post-ejaculation (RAW. Each semen sample was processed for colloidal centrifugation. The percentage of abnormal spermatozoa was 17.8 ± 7.0% in RAW and 14.6 ± 9.5% in FRAC-1 but decreased to 11.4 ± 4.7% and 9.6 ± 6.9% respectively, after colloidal centrifugation. A sperm DNA fragmentation index of 10.9 ± 5.1% was observed in RAW and 7.5 ± 2.4% in FRAC-1 semen collected with the AV but this decreased to 7.8 ± 2.8% and 5.2 ± 2.3% after colloidal centrifugation. The rate of increase in sperm DNA fragmentation during the first 6 h of incubation at 37 ºC was 1.8 ± 0.9% per hour in RAW semen and 2.0 ± 2.0% per hour in FRAC-1 but this significantly decreased to 1.3 ± 1.4% and 0.9 ± 0.8% respectively after colloidal centrifugation. While stallion seminal characteristics can be improved using colloidal centrifugation, further enhancement is possible if the ejaculate is initially fractionated.

  6. 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.

  7. Cost- and energy-efficient dehydration of unconventional oil using disc-stack centrifuges

    Energy Technology Data Exchange (ETDEWEB)

    Agrell, J. [Alfa Laval Tumba AB, Stockholm (Sweden)

    2008-07-01

    Centrifuge dehydration methods for heavy oils were discussed. The high viscosity of heavy oils can mean that emulsions are often stabilized by surface-active compounds that occur naturally in the oil during dehydration processes. Disc-stack centrifuges are used to dehydrate crude oils without the excessive need for chemical treatments and wash water. The lower separation temperatures mean that dehydration can be accomplished with reduced energy inputs and lower carbon dioxide (CO{sub 2}) emissions. The main challenges to efficient crude oil dehydration were identified as the small density difference between oil and water; high oil viscosity; higher solids content; and the tight emulsions formed through oil processing. It was concluded that separation at higher viscosities leads to reduced heating requirements and increased energy savings. Continuous solids discharge make it possible for large amounts of solids to be processed. 3 refs.

  8. Prediction and verification of centrifugal dewatering of P. pastoris fermentation cultures using an ultra scale-down approach.

    Science.gov (United States)

    Lopes, A G; Keshavarz-Moore, E

    2012-08-01

    Recent years have seen a dramatic rise in fermentation broth cell densities and a shift to extracellular product expression in microbial cells. As a result, dewatering characteristics during cell separation is of importance, as any liquor trapped in the sediment results in loss of product, and thus a decrease in product recovery. In this study, an ultra scale-down (USD) approach was developed to enable the rapid assessment of dewatering performance of pilot-scale centrifuges with intermittent solids discharge. The results were then verified at scale for two types of pilot-scale centrifuges: a tubular bowl equipment and a disk-stack centrifuge. Initial experiments showed that employing a laboratory-scale centrifugal mimic based on using a comparable feed concentration to that of the pilot-scale centrifuge, does not successfully predict the dewatering performance at scale (P-value dewatering levels was achieved using the USD method (P-value ≥0.05), based on using a feed concentration at small-scale that mimicked the same height of solids as that in the pilot-scale centrifuge. Initial experiments used Baker's yeast feed suspensions followed by fresh Pichia pastoris fermentation cultures. This work presents a simple and novel USD approach to predict dewatering levels in two types of pilot-scale centrifuges using small quantities of feedstock (<50 mL). It is a useful tool to determine optimal conditions under which the pilot-scale centrifuge needs to be operated, reducing the need for repeated pilot-scale runs during early stages of process development.

  9. Solanidine isolation from Solanum tuberosum by centrifugal partition chromatography.

    Science.gov (United States)

    Attoumbré, Jacques; Giordanengo, Philippe; Baltora-Rosset, Sylvie

    2013-07-01

    The aim of this investigation was the preparative isolation of solanidine (aglycone of the two main potato glycoalkaloids: α-chaconine and α-solanine) from fresh Solanum tuberosum (cv. Pompadour) material by implementing a new preparation scheme using centrifugal partition chromatography (CPC). A setup for obtaining solanidine by hydrolysis of the glycoalkaloids found in the skin and sprouts of S. tuberosum was first developed. Then its isolation was carried out by the development of CPC conditions: the solvent system used for separation was ethyl acetate/butanol/water in the ratio 42.5:7.5:50 v/v/v, 0.6 g of crude extract were separated with a 8 mL/min flow rate of mobile phase while rotating at 2500 rpm. A run yielded 98 mg of solanidine (86.7% recovery from the crude extract) in a one-step separation. The purity of the isolated solanidine was over 98%. Thus, CPC has proven to be the method of choice to get solanidine of very high purity from S. tuberosum biomass in large quantities.

  10. On Continuous Magnetically Enhanced Centrifugation in Large Scale Downstream Processing of Bioproducts

    OpenAIRE

    Lindner, Johannes

    2014-01-01

    The current thesis targets on the technical use of Magnetically Enhanced Centrifugation (MEC). Aim is the understanding of the mechanisms of particle transport out of the magnetic field by simulations of the phenomena, and the realization of MEC in a large scale. Industrial scale machines for batch-wise and continuous discharge were tested. The use of synthetic magnetic particles with functionalized surface allows the separation of non-magnetic matter.

  11. Computer assisted centrifugal elutriation I: detection system and data acquisition equipment

    OpenAIRE

    P.M.A. Sloot; Carels, M.J.; Tensen, P.; Figdor, C. G.

    1987-01-01

    To optimize cell separations by centrifugal elutriation, we constructed an on-line computer-controlled multiparametric light-scatter system. A bypass sample flow, at the outlet of an elutriation rotor, is hydrofocussed and three scatter parameters of each cell are determined up to a maximum of 15 000 cells/second. The 18-bit representation of the parameter values are cumulatively stored by means of a direct memory access interface. The histogram memory is continuously displayed to provide inf...

  12. 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.

  13. 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...

  14. Possible biomedical applications and limitations of a variable-force centrifuge on the lunar surface: A research tool and an enabling resource

    Science.gov (United States)

    Cowing, Keith L.

    1992-01-01

    Centrifuges will continue to serve as a valuable research tool in gaining an understanding of the biological significance of the inertial acceleration due to gravity. Space- and possibly lunar-based centrifuges will play a significant and enabling role with regard to the human component of future lunar and martian exploration, both as a means of accessing potential health and performance risks and as a means of alleviating these risks. Lunar-based centrifuges could be particularly useful as part of a program of physiologic countermeasures designed to alleviate the physical deconditioning that may result from prolonged exposure to a 1/6-g environment. Centrifuges on the lunar surface could also be used as part of a high-fidelity simulation of a trip to Mars. Other uses could include crew readaptation to 1 g, waste separation, materials processing, optical mirror production in situ on the Moon, and laboratory specimen separation.

  15. A Parametric Study for High-Efficiency Gas-Liquid Separator Design

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A gas liquid centrifugal separator is widely used in industry on account of its simple geometry and little maintenance. These separators have considerable advantages over filters, scrubbers or precipitators in term of compact design, lower pressure drop and higher capacity. A gas liquid centrifugal separator is a device that utilizes centrifugal forces and low pressure caused by rotational motion to separate liquid from gas by density differences.Efficient and reliable separation is required for the optimum operation. These separators axe often operated at less than peak efficiency due to the entrainment of separated liquid through an outlet pipe which is closely associated with the very complicated flow phenomena involved. Design parameters such as length of the separation space,vane exit angle, inlet to outlet diameter ratio, models for separation efficiency and pressure drop as a function of physical dimensions are not available in literature. This leaves the designer with very little to go on except known designs and experimentation. The aim of present study is to perform a parametric study to get higher efficiency for gas-liquid separator. A parametric study has been carried out with the help of CFD tools to analyze a separation performance of a centrifugal separator by varying the length of separator space. The best design parameters are analyzed based upon obtained results, tangential velocities, vortices, total pressure losses. From the present study several attempts are made to improve the performance of conventional centrifugal separators.

  16. 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.

  17. 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...

  18. 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)

  19. 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.

  20. A specter of coexistence: Is centrifugal community organization haunted by the ghost of competition?

    Science.gov (United States)

    Wasserberg, G.; Kotler, B.P.; Morris, D.W.; Abramsky, Z.

    2006-01-01

    In a centrifugally organized community species prefer the same habitat (called "core") but differ in their secondary habitat preferences. The first model of centrifugal community organization (CCO) predicted that optimally foraging, symmetrically competing species would share use of the core habitat at all density combinations. But one might also assume that the competition in the core habitat is asymmetrical, that is, that one of the species (the dominant) has a behavioral advantage therein. In this study, we asked how should habitat use evolve in a centrifugally organized community if its species compete asymmetrically in the core habitat? To address this question we developed an "isoleg model". The model predicts that in a centrifugally organized community, asymmetric competition promotes the use of the core habitat exclusively by the dominant species at most points in the state space. The separation of the core habitat use by the species ("the ghost of competition past") may be either complete or partial ("partial ghost"), and behavior at the stable competitive equilibrium between the species could determine whether coexistence should occur at the "complete-" or the "partial ghost" regions. This version of CCO should be a common feature of competitive systems.

  1. Equipment Design of Camellia Fruit and Shell Separating by Micro-wave

    Directory of Open Access Journals (Sweden)

    Jian Zhou

    2015-07-01

    Full Text Available For obtaining excellent properties of separating Camellia fruit and shell, the micro-wave technology is used, the separating equipment is also designed. The set includes lifting raw material system, micro-wave controlling system, eliminating wet system, micro-wave affection body, dropping material system. The camellia fruits are transported into micro-wave system, then they are crashed with centrifugal throwing disc, by the affect of wind and centrifugal force, thus shells and seeds are separated obviously.

  2. Development of an efficient soymilk cream production method by papain digestion, heat treatment, and low-speed centrifugation.

    Science.gov (United States)

    Abe, Naoki; Wu, Chang-Yu; Kim, Yoon-Kyung; Fujii, Tomoyuki; Abe, Keietsu

    2015-01-01

    We developed the simple method of soymilk cream production from the high-fat soymilk, which was prepared by papain digestion and heat treatment. As a result of the treatment, high-fat soymilk was aggregated and it became possible to separate soymilk cream as the surface fraction by low-speed centrifugation (6000 × g, 10 min).

  3. High Technology Centrifugal Compressor for Commercial Air Conditioning Systems

    Energy Technology Data Exchange (ETDEWEB)

    Ruckes, John

    2006-04-15

    R&D Dynamics, Bloomfield, CT in partnership with the State of Connecticut has been developing a high technology, oil-free, energy-efficient centrifugal compressor called CENVA for commercial air conditioning systems under a program funded by the US Department of Energy. The CENVA compressor applies the foil bearing technology used in all modern aircraft, civil and military, air conditioning systems. The CENVA compressor will enhance the efficiency of water and air cooled chillers, packaged roof top units, and other air conditioning systems by providing an 18% reduction in energy consumption in the unit capacity range of 25 to 350 tons of refrigeration The technical approach for CENVA involved the design and development of a high-speed, oil-free foil gas bearing-supported two-stage centrifugal compressor, CENVA encompassed the following high technologies, which are not currently utilized in commercial air conditioning systems: Foil gas bearings operating in HFC-134a; Efficient centrifugal impellers and diffusers; High speed motors and drives; and System integration of above technologies. Extensive design, development and testing efforts were carried out. Significant accomplishments achieved under this program are: (1) A total of 26 builds and over 200 tests were successfully completed with successively improved designs; (2) Use of foil gas bearings in refrigerant R134a was successfully proven; (3) A high speed, high power permanent magnet motor was developed; (4) An encoder was used for signal feedback between motor and controller. Due to temperature limitations of the encoder, the compressor could not operate at higher speed and in turn at higher pressure. In order to alleviate this problem a unique sensorless controller was developed; (5) This controller has successfully been tested as stand alone; however, it has not yet been integrated and tested as a system; (6) The compressor successfully operated at water cooled condensing temperatures Due to temperature

  4. Separation phenomena in Liquids and Gases

    Energy Technology Data Exchange (ETDEWEB)

    Louvet, P.; Dr Soubbaramayer [CEA Saclay, Dept. des Lasers et de la Physico-Chimie, DESICP/DLPC/SPP, 91 - Gif-sur-Yvette (France); Noe, P

    1989-07-01

    The Proceedings of the 1989 Workshop are presented in two volumes: volume 1 contains 4 papers on plasma processes and 7 papers on centrifugation. The papers on plasma processes deal with two main methods: ion cyclotron resonance and rotating plasmas. A survey lecture reviews extensively the physics of the two processes, the published experimental results and includes an abundant bibliography of about 200 references. The 3 other papers communicate original and recent experiments carried out by the authors. The plasma process remains as a possible technology to separate stable isotopes and isotopes of metals located in the middle of the Mendeleev Table. Regarding the stable isotopes, the ion cyclotron resonance might be an alternative to the Calutron process. The sessions on centrifugation include 2 review papers by URENCO authors and 5 specialized communications. The review papers take stock of the centrifuge research and gives the current status of the centrifuge technology in URENCO. The authors say that the centrifugation is presently an established industrial and commercial process ready to enter in competition for any new construction of enrichment capacity. Volume 2 contains the papers on 3 topics: basic studies (11 papers), chemical process (2 papers) and laser processes (7 papers). The papers on basic studies include investigations on rotating flows. A special attention is given to studies on convection flows, driven by acceleration field or (and) capillary forces. The interest of convection is obvious, as it has applications in important fields: the hydrodynamics of liquid uranium in the evaporation crucible of AVLIS Process, the crystal growth experiments on earth or under microgravity conditions (future experiments planned in space-labs) and the welding by electron or photon beams. Two papers are presented on the chemical process and both of them are by French authors. The French CEA has, in the past, developed with success the CHEMEX process. The

  5. Short communication: Improved method for centrifugal recovery of bacteria from raw milk applied to sensitive real-time quantitative PCR detection of Salmonella spp

    Science.gov (United States)

    Centrifugation of milk is widely used as a separation/concentration step in assays for pathogenic microorganisms. Separation of the cream and liquid supernate from the pellet containing sedimented solids, somatic cells and microorganisms eliminates many interfering substances, and resuspension of th...

  6. 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.

  7. 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...

  8. 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.

  9. Method of separating a surfactant from a liquid

    NARCIS (Netherlands)

    Van den Berg, A.W.; Lems, S.

    2002-01-01

    The present invention relates to a method of separating a surfactant from a liquid, such as a wastewater stream from an industrial laundry. In accordance with the invention, the liquid is cooled to below the Krafft temperature of the surfactant and subjected to centrifugal forces for the separation

  10. 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.

  11. 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.

  12. 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.

  13. Trajectory and terminal distribution of single centrifugal axons from olfactory cortical areas in the rat olfactory bulb.

    Science.gov (United States)

    Matsutani, S

    2010-08-11

    The olfactory bulb receives a large number of centrifugal fibers whose functions remain unclear. To gain insight into the function of the bulbar centrifugal system, the morphology of individual centrifugal axons from olfactory cortical areas was examined in detail. An anterograde tracer, Phaseolus vulgaris leucoagglutinin, was injected into rat olfactory cortical areas, including the pars lateralis of the anterior olfactory nucleus (lAON) and the anterior part of the piriform cortex (aPC). Reconstruction from serial sections revealed that the extrabulbar segments of centrifugal axons from the lAON and those from the aPC had distinct trajectories: the former tended to innervate the pars externa of the AON before entering the olfactory bulb, while the latter had extrabulbar collaterals that extended to a variety of targets. In contrast to the extrabulbar segments, no clear differences were found between the intrabulbar segments of axons from the lAON and from the aPC. The intrabulbar segments of centrifugal axons were mainly found in the granule cell layer but a few axons extended into the external plexiform and glomerular layer. Approximately 40% of centrifugal axons innervated both the medial and lateral aspects of the olfactory bulb. The number of boutons found on single intrabulbar segments was typically less than 1000. Boutons tended to aggregate and form complex terminal tufts with short axonal branches. Terminal tufts, no more than 10 in single axons from ipsilateral cortical areas, were localized to the granule cell layer with varying intervals; some tufts formed patchy clusters and others were scattered over areas that extended for a few millimeters. The patchy, widespread distribution of terminals suggests that the centrifugal axons are able to couple the activity of specific subsets of bulbar neurons even when the subsets are spatially separated.

  14. Centrifugal microfluidic platform for radiochemistry: potentialities for the chemical analysis of nuclear spent fuels.

    Science.gov (United States)

    Bruchet, Anthony; Taniga, Vélan; Descroix, Stéphanie; Malaquin, Laurent; Goutelard, Florence; Mariet, Clarisse

    2013-11-15

    The use of a centrifugal microfluidic platform is for the first time reported as an alternative to classical chromatographic procedures for radiochemistry. The original design of the microfluidic platform has been thought to fasten and simplify the prototyping process with the use of a circular platform integrating four rectangular microchips made of thermoplastic. The microchips, dedicated to anion-exchange chromatographic separations, integrate a localized monolithic stationary phase as well as injection and collection reservoirs. The results presented here were obtained with a simplified simulated nuclear spent fuel sample composed of non-radioactive isotopes of Europium and Uranium, in proportion usually found for uranium oxide nuclear spent fuel. While keeping the analytical results consistent with the conventional procedure (extraction yield for Europium of ≈97%), the use of the centrifugal microfluidic platform allowed to reduce the volume of liquid needed by a factor of ≈250. Thanks to their unique "easy-to-use" features, centrifugal microfluidic platforms are potential successful candidates for the downscaling of chromatographic separation of radioactive samples (automation, multiplexing, easy integration in glove-boxes environment and low cost of maintenance).

  15. Evaluation of erythrocyte flow at a bearing gap in a hydrodynamically levitated centrifugal blood pump.

    Science.gov (United States)

    Murashige, Tomotaka; Kosaka, Ryo; Sakota, Daisuke; Nishida, Masahiro; Kawaguchi, Yasuo; Yamane, Takashi; Maruyama, Osamu

    2015-01-01

    We have developed a hydrodynamically levitated centrifugal blood pump for extracorporeal circulatory support. In the blood pump, a spiral groove bearing was adopted for a thrust bearing. In the spiral groove bearing, separation of erythrocytes and plasma by plasma skimming has been postulated to occur. However, it is not clarified that plasma skimming occurs in a spiral groove bearing. The purpose of this study is to verify whether plasma skimming occurs in the spiral groove bearing of a hydrodynamically levitated centrifugal blood pump. For evaluation of plasma skimming in the spiral groove bearing, an impeller levitation performance test using a laser focus displacement meter and a microscopic visualization test of erythrocyte flow using a high-speed microscope were conducted. Bovine blood diluted with autologous plasma to adjust hematocrit to 1.0% was used as a working fluid. Hematocrit on the ridge region in the spiral groove bearing was estimated using image analysis. As a result, hematocrits on the ridge region with gaps of 45 μm, 31 μm, and 25 μm were calculated as 1.0%, 0.6%, and 0.3%, respectively. Maximum skimming efficiency in this study was calculated as 70% with a gap of 25 μm. We confirmed that separation of erythrocyte and plasma occurred in the spiral groove bearing with decrease in bearing gap in a hydrodynamically levitated centrifugal blood pump.

  16. [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.

  17. 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.

  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. 2011 IEEE Visualization Contest Winner: Visualizing Unsteady Vortical Behavior of a Centrifugal Pump

    KAUST Repository

    Otto, Mathias

    2012-09-01

    In the 2011 IEEE Visualization Contest, the dataset represented a high-resolution simulation of a centrifugal pump operating below optimal speed. The goal was to find suitable visualization techniques to identify regions of rotating stall that impede the pump\\'s effectiveness. The winning entry split analysis of the pump into three parts based on the pump\\'s functional behavior. It then applied local and integration-based methods to communicate the unsteady flow behavior in different regions of the dataset. This research formed the basis for a comparison of common vortex extractors and more recent methods. In particular, integration-based methods (separation measures, accumulated scalar fields, particle path lines, and advection textures) are well suited to capture the complex time-dependent flow behavior. This video (http://youtu.be/ oD7QuabY0oU) shows simulations of unsteady flow in a centrifugal pump. © 2012 IEEE.

  20. 2011 IEEE Visualization Contest winner: Visualizing unsteady vortical behavior of a centrifugal pump.

    Science.gov (United States)

    Otto, Mathias; Kuhn, Alexander; Engelke, Wito; Theisel, Holger

    2012-01-01

    In the 2011 IEEE Visualization Contest, the dataset represented a high-resolution simulation of a centrifugal pump operating below optimal speed. The goal was to find suitable visualization techniques to identify regions of rotating stall that impede the pump's effectiveness. The winning entry split analysis of the pump into three parts based on the pump's functional behavior. It then applied local and integration-based methods to communicate the unsteady flow behavior in different regions of the dataset. This research formed the basis for a comparison of common vortex extractors and more recent methods. In particular, integration-based methods (separation measures, accumulated scalar fields, particle path lines, and advection textures) are well suited to capture the complex time-dependent flow behavior. This video (http://youtu.be/oD7QuabY0oU) shows simulations of unsteady flow in a centrifugal pump.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. An asymmetric tubular ceramic-carbonate dual phase membrane for high temperature CO2 separation.

    Science.gov (United States)

    Dong, Xueliang; Ortiz Landeros, José; Lin, Y S

    2013-10-25

    For the first time, a tubular asymmetric ceramic-carbonate dual phase membrane was prepared by a centrifugal casting technique and used for high temperature CO2 separation. This membrane shows high CO2 permeation flux and permeance.

  6. Novel design for centrifugal counter-current chromatography: VI. Ellipsoid column.

    Science.gov (United States)

    Gu, Dongyu; Yang, Yi; Xin, Xuelei; Aisa, Haji Akber; Ito, Yoichiro

    2015-01-01

    A novel ellipsoid column was designed for centrifugal counter-current chromatography. Performance of the ellipsoid column with a capacity of 3.4 mL was examined with three different solvent systems composed of 1-butanol-acetic acid-water (4:1:5, v/v) (BAW), hexane-ethyl acetate-methanol-0.1 M HCl (1:1:1:1, v/v) (HEMH), and 12.5% (w/w) PEG1000 and 12.5% (w/w) dibasic potassium phosphate in water (PEG-DPP) each with suitable test samples. In dipeptide separation with BAW system, both stationary phase retention (Sf) and peak resolution (Rs) of the ellipsoid column were much higher at 0° column angle (column axis parallel to the centrifugal force) than at 90° column angle (column axis perpendicular to the centrifugal force), where elution with the lower phase at a low flow rate produced the best separation yielding Rs at 2.02 with 27.8% Sf at a flow rate of 0.07 ml/min. In the DNP-amino acid separation with HEMW system, the best results were obtained at a flow rate of 0.05 ml/min with 31.6% Sf yielding high Rs values at 2.16 between DNP-DL-glu and DNP-β-ala peaks and 1.81 between DNP-β-ala and DNP-L-ala peaks. In protein separation with PEG-DPP system, lysozyme and myolobin were resolved at Rs of 1.08 at a flow rate of 0.03 ml/min with 38.9% Sf. Most of those Rs values exceed those obtained from the figure-8 column under similar experimental conditions previously reported.

  7. Liquid Metering Centrifuge Sticks (LMCS): A Centrifugal Approach to Metering Known Sample Volumes for Colorimetric Solid Phase Extraction (C-SPE)

    Science.gov (United States)

    Gazda, Daniel B.; Schultz, John R.; Clarke, Mark S.

    2007-01-01

    Phase separation is one of the most significant obstacles encountered during the development of analytical methods for water quality monitoring in spacecraft environments. Removing air bubbles from water samples prior to analysis is a routine task on earth; however, in the absence of gravity, this routine task becomes extremely difficult. This paper details the development and initial ground testing of liquid metering centrifuge sticks (LMCS), devices designed to collect and meter a known volume of bubble-free water in microgravity. The LMCS uses centrifugal force to eliminate entrapped air and reproducibly meter liquid sample volumes for analysis with Colorimetric Solid Phase Extraction (C-SPE). C-SPE is a sorption-spectrophotometric platform that is being developed as a potential spacecraft water quality monitoring system. C-SPE utilizes solid phase extraction membranes impregnated with analyte-specific colorimetric reagents to concentrate and complex target analytes in spacecraft water samples. The mass of analyte extracted from the water sample is determined using diffuse reflectance (DR) data collected from the membrane surface and an analyte-specific calibration curve. The analyte concentration can then be calculated from the mass of extracted analyte and the volume of the sample analyzed. Previous flight experiments conducted in microgravity conditions aboard the NASA KC-135 aircraft demonstrated that the inability to collect and meter a known volume of water using a syringe was a limiting factor in the accuracy of C-SPE measurements. Herein, results obtained from ground based C-SPE experiments using ionic silver as a test analyte and either the LMCS or syringes for sample metering are compared to evaluate the performance of the LMCS. These results indicate very good agreement between the two sample metering methods and clearly illustrate the potential of utilizing centrifugal forces to achieve phase separation and metering of water samples in microgravity.

  8. Wide dynamic range enrichment method of semiconducting single-walled carbon nanotubes with weak field centrifugation.

    Science.gov (United States)

    Reis, Wieland G; Tomović, Željko; Weitz, R Thomas; Krupke, Ralph; Mikhael, Jules

    2017-03-20

    The potential of single-walled carbon nanotubes (SWCNTs) to outperform silicon in electronic application was finally enabled through selective separation of semiconducting nanotubes from the as-synthesized statistical mix with polymeric dispersants. Such separation methods provide typically high semiconducting purity samples with narrow diameter distribution, i.e. almost single chiralities. But for a wide range of applications high purity mixtures of small and large diameters are sufficient or even required. Here we proof that weak field centrifugation is a diameter independent method for enrichment of semiconducting nanotubes. We show that the non-selective and strong adsorption of polyarylether dispersants on nanostructured carbon surfaces enables simple separation of diverse raw materials with different SWCNT diameter. In addition and for the first time, we demonstrate that increased temperature enables higher purity separation. Furthermore we show that the mode of action behind this electronic enrichment is strongly connected to both colloidal stability and protonation. By giving simple access to electronically sorted SWCNTs of any diameter, the wide dynamic range of weak field centrifugation can provide economical relevance to SWCNTs.

  9. [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.

  10. 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.

  11. 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.

  12. Isolation of Methoxyfuranocoumarins From Ammi majus by Centrifugal Partition Chromatography.

    Science.gov (United States)

    Bartnik, Magdalena; Mazurek, Anna Katarzyna

    2016-01-01

    Pure methoxyfuranocoumarins were isolated from Ammi majus L. by use of low-pressure column chromatography (LPCC) followed by centrifugal partition chromatography (CPC). The concentrated petroleum ether extract from fruits of A. majus was fractionated on a silica gel column using a gradient of ethyl acetate in dichloromethane (0-80%, v/v). Coumarin-rich fractions were analyzed by thin-layer chromatography (TLC) and high-performance liquid chromatography with diode array detection (HPLC/DAD). Xanthotoxin (8-MOP) and isopimpinellin (isoP), structurally similar compounds, were isolated in one fraction (FR6). To avoid multistep and long-lasting TLC preparation, optimization of CPC conditions has been performed. In one run, an effective separation of 8-MOP and isoP was achieved. The two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (10 : 8 : 10 : 9; v/v) in an ascending mode (the aqueous phase was a stationary phase, and the organic phase was a mobile phase), with flow rate 3 mL/min and rotation speed 1,600 r.p.m., was used. The identification and high purities of isolated 8-MOP (98.7%) and isoP (100%) were confirmed by HPLC/DAD assay, when compared with standards. The developed CPC method could be applied to the effective isolation of 8-MOP and isoP from plant extracts. The high purity of obtained compounds makes possible further exploitation of these components in biological studies.

  13. Centrifugal Distortion Causes Anderson Localization in Laser Kicked Molecules

    Science.gov (United States)

    Floss, Johannes; Averbukh, Ilya Sh.

    2014-05-01

    The periodically kicked 2D rotor is a textbook model in nonlinear dynamics. The classical kicked rotor can exhibit truly chaotic motion, whilst in the quantum regime this chaotic motion is suppressed by a mechanism similar to Anderson Localization. Up to now, these effects have been mainly observed in an atom optics analogue of a quantum rotor: cold atoms in a standing light wave. We demonstrate that common linear molecules (like N2, O2, CO2, ...), kicked by a train of short linearly polarized laser pulses, can exhibit a new mechanism for dynamical Anderson Localization due to their non-rigidity. When the pulses are separated by the rotational revival time trev = πℏ / B , the angular momentum J grows ballistically (Quantum Resonance). We show that, due to the centrifugal distortion of fast spinning molecules, above some critical value J =Jcr the Quantum Resonance is suppressed via the mechanism of Anderson Localization. This leads to a non-sinusoidal oscillation of the angular momentum distribution, which may be experimentally observed even at ambient conditions by using current techniques for laser molecular alignment.

  14. Evaluation of floating impeller phenomena in a Gyro centrifugal pump.

    Science.gov (United States)

    Nishimura, Ikuya; Ichikawa, S; Mikami, M; Ishitoya, H; Motomura, T; Kawamura, M; Linneweber, J; Glueck, J; Shinohara, T; Nosé, Y

    2013-01-01

    The Gyro centrifugal pump developed as a totally implantable artificial heart was designed with a free impeller, in which the rotational shaft (male bearing) of the impeller was completely separated from the female bearing. For this type of pump, it is very important to keep the proper magnet balance (impeller-magnet and actuator-magnet) in order to prevent thrombus formation and/or bearing wear. When the magnet balance is not proper, the impeller is jerked down into the bottom bearing. On the other hand, if magnet balance is proper, the impeller lifted off the bottom of the pump housing within a certain range of pumping conditions. In this study, this floating phenomenon was investigated in detail. The floating phenomenon was proved by observation of the impeller behavior using a transparent acrylic pump. The impeller floating phenomenon was mapped on a pump performance curve. The impeller floating phenomenon is affected by the magnet-magnet coupling distance and rotational speed of the impeller. In order to keep the proper magnet balance and to maintain the impeller floating phenomenon at the driving condition of right and left pump, the magnet-magnet coupling distance was altered by a spacer which was installed between the pump and actuator. It became clear that the same pump could handle different conditions (right and left ventricular assist), by just changing the thickness of the spacer. When magnet balance is proper, the floating impeller phenomenon occurs automatically in response to the impeller rev. It is called "the dynamic RPM suspension".

  15. 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.

  16. 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.

  17. Task 9 -- Centrifugal membrane filtration. Semi-annual report, April 1--September 30, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Stepan, D.J.; Grafsgaard, M.E.

    1997-12-31

    This project is designed to establish the utility of a novel centrifugal membrane filtration technology for the remediation of liquid mixed waste streams at US Department of Energy (DOE) facilities in support of the DOE Environmental Management (EM) program. The Energy and Environmental Research Center (EERC) has teamed with SpinTek Membrane Systems, Inc., a small business and owner of the novel centrifugal membrane filtration technology, to establish the applicability of the technology to DOE site remediation and the commercial viability of the technology for liquid mixed waste stream remediation. The technology is a uniquely configured process that makes use of ultrafiltration and centrifugal force to separate suspended and dissolved solids from liquid waste streams, producing a filtered water stream and a low-volume contaminated concentrate stream. This technology has the potential for effective and efficient waste volume minimization, the treatment of liquid tank wastes, the remediation of contaminated groundwater plumes, and the treatment of secondary liquid waste streams from other remediation processes, as well as the liquid waste stream generated during decontamination and decommissioning activities.

  18. Internal flow numerical simulation of double-suction centrifugal pump using DES model

    Science.gov (United States)

    Zhou, P. J.; Wang, F. J.; Yang, M.

    2012-11-01

    It is a challenging task for the flow simulation for a double-suction centrifugal pump, because the wall effects are strong in this type of pumps. Detached-eddy simulation (DES), referred as a hybrid RANS-LES approach, has emerged recently as a potential compromise between RANS based turbulence models and Large Eddy Simulation. In this approach, the unsteady RANS model is employed in the boundary layer, while the LES treatment is applied to the separated region. In this paper, S-A DES method and SST k-ω DES method are applied to the numerical simulation for the 3D flow in whole passage of a double-suction centrifugal pump. The unsteady flow field including velocity and pressure distributions is obtained. The head and efficiency of the pump are predicted and compared with experimental results. According to the calculated results, S-A DES model is easy to control the partition of the simulation when using near wall grid with 30 suction centrifugal pump. S-A DES method can capture more flow phenomenon than SST k - ω DES method. In addition, it can accurately predict the power performance under different flow conditions, and can reflect pressure fluctuation characteristics.

  19. Process intensification technologies for biodiesel production reactive separation processes

    CERN Document Server

    Kiss, A A

    2014-01-01

    This book is among the first to address the novel process intensification technologies for biodiesel production, in particular the integrated reactive separations. It provides a comprehensive overview illustrated with many industrially relevant examples of novel reactive separation processes used in the production of biodiesel (e.g. fatty acid alkyl esters): reactive distillation, reactive absorption, reactive extraction, membrane reactors, and centrifugal contact separators. Readers will also learn about the working principles, design and control of integrated processes, while also getting a

  20. Sample of CFD optimization of a centrifugal compressor stage

    Science.gov (United States)

    Galerkin, Y.; Drozdov, A.

    2015-08-01

    Industrial centrifugal compressor stage is a complicated object for gas dynamic design when the goal is to achieve maximum efficiency. The Authors analyzed results of CFD performance modeling (NUMECA Fine Turbo calculations). Performance prediction in a whole was modest or poor in all known cases. Maximum efficiency prediction was quite satisfactory to the contrary. Flow structure in stator elements was in a good agreement with known data. The intermediate type stage “3D impeller + vaneless diffuser+ return channel” was designed with principles well proven for stages with 2D impellers. CFD calculations of vaneless diffuser candidates demonstrated flow separation in VLD with constant width. The candidate with symmetrically tampered inlet part b3 / b2 = 0,73 appeared to be the best. Flow separation takes place in the crossover with standard configuration. The alternative variant was developed and numerically tested. The obtained experience was formulated as corrected design recommendations. Several candidates of the impeller were compared by maximum efficiency of the stage. The variant with gas dynamic standard principles of blade cascade design appeared to be the best. Quasi - 3D non-viscid calculations were applied to optimize blade velocity diagrams - non-incidence inlet, control of the diffusion factor and of average blade load. “Geometric” principle of blade formation with linear change of blade angles along its length appeared to be less effective. Candidates’ with different geometry parameters were designed by 6th math model version and compared. The candidate with optimal parameters - number of blades, inlet diameter and leading edge meridian position - is 1% more effective than the stage of the initial design.

  1. Early Silicate Liquid Immiscibility in the Skaergaard Intrusion: Evidence from high Temperature Centrifugation Experiments

    Science.gov (United States)

    Veksler, I.; Dorfman, A. M.; Borisov, A. A.; Wirth, R.; Dingwell, D. B.

    2007-12-01

    Immiscible droplet textures are common in groundmass glasses and plagioclase-hosted melt inclusions of tholeiitic basalts (Philpotts, 1982). Our experiments on synthetic analogues of natural immiscible basaltic-rhyolitic glasses showed that conventional quenching experiments in 1-atm gas mixing furnaces were in most cases unable to reproduce unmixing yielding instead either turbid, opalescent glasses, or crystallization of tridymite and pyroxenes. In contrast, experiments involving in situ high-temperature centrifugation at 1000g on some of the liquids did yield macroscopic unmixing and phase separation. It appears that experimental reproduction of immiscibility in complex ferrobabsaltic aluminosilicate melts is hampered by nucleation barrier, metastable crystallization, and sluggish phase separation kinetics. Three-four hours of centrifugation were insufficient to complete phase segregation, and resulted in sub-micron immiscible emulsions in quenched glasses. For a model liquid composition of the Middle Zone of the Skaergaard intrusion obtained from experiments by Toplis and Carroll (1995) centrifugation at super-liquidus temperatures of 1110-1120 degrees C, produced a thin, silicic layer (64.5 wt.% SiO2 and 7.4 wt.% FeO) at the top of the main Fe-rich glass (46 wt.% SiO2 and 21 wt.% FeO). Transmission electron microscopy of the quenched products revealed silica-rich immiscible globules of about 20--30 nm in diameter suspended in the Fe-rich glass. The globules are however not a quench feature because they moved during centrifugation over a few millimeters of the sample length and eventually accumulated in the thin (0.2 mm) silicic liquid layer at the top. The divergent compositions of the top and at the bottom were shown in a series of static runs to crystallize very similar crystal assemblages of plagioclase, pyroxene, olivine, and Fe-Ti oxides. In light of our centrifuge experiments, immiscibility in the Skaergaard intrusion may have started already at the

  2. Sludge Water Characteristics Under Different Separation Methods from a Membrane Bioreactor

    KAUST Repository

    Wei, Chunhai

    2013-11-22

    The concept of sludge water was proposed to integrate the relative terminologies and its characteristics under different separation methods from a membrane bioreactor (MBR) were investigated in this study. Based on chemical oxygen demand (COD) and three-dimensional fluorescence excitation-emission matrix (F-EEM), and compared with the control (gravitational sedimentation), some suspended particulate organics or biopolymer clusters (mainly proteins) were released from sludge flocs into the supernatant after centrifugation under low to middle centrifugal forces (10-4000 g) and then aggregated into a pellet under high centrifugal forces (10000-20000 g). Filtration (1.2 μm glass fiber filter) produced sludge water with a lower biopolymers concentration than the control (gravitational sedimentation followed by filtration) due to cake layer formation during filtration. As for centrifugation followed by filtration, low to middle centrifugal forces did not significantly affect sludge water characteristics but high centrifugal forces reduced the concentrations of some proteins in sludge water from advanced analytical protocols including F-EEM and liquid chromatography with on-line organic carbon detection (LC-OCD), demonstrating a low to middle centrifugal force suitable for MBR sludge water separation. From LC-OCD, the main fractions of sludge water were humic substances and building blocks, low molecular weight neutrals and biopolymers (mainly proteins rather than polysaccharides). Supplemental materials are available for this article. Go to the publisher\\'s online edition of Separation Science and Technology to view the supplemental file. © 2013 Copyright Taylor and Francis Group, LLC.

  3. 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.

  4. Use of neural network for the simulation of a gas centrifuge

    Energy Technology Data Exchange (ETDEWEB)

    Migliavacca, Sylvana C. Presti; Rodrigues, C. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil); Nascimento, Claudio A.O. Nascimento [Sao Paulo Univ., SP (Brazil). Escola Politecnica; Vasconcelos Andrade, Monica de C. [Centro Tecnologico da Marinha, Sao Paulo, SP (Brazil)

    1996-12-31

    The authors propose the use of neural networks for the simulation and prediction of the separative and operational parameters of a gas centrifuge separating uranium isotopes. The last set of experimental data in the open literature, seems to be presented by Zippe (1960). The results from the uranium separation experiments are compiled and presented to the neural network in the learning and testing processes. The best structure is then chosen to minimize the total error. The parameters calculated by the neural network are then compared with the experimental data and with some theoretical results. The prediction using the neural network model shows good agreement with the experimental data. (author) 21 refs., 17 figs., 5 tabs.

  5. 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.

  6. 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

  7. 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.

  8. 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,...

  9. 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.

  10. 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...

  11. 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...

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  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. Separation Logic

    DEFF Research Database (Denmark)

    Reynolds, John C.

    2002-01-01

    expressions) for accessing and modifying shared structures, and for explicit allocation and deallocation of storage. Assertions are extended by introducing a "separating conjunction" that asserts that its sub-formulas hold for disjoint parts of the heap, and a closely related "separating implication". Coupled......, dynamically allocated arrays, and recursive procedures. We will also discuss promising future directions....

  18. 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...

  19. 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.

  20. 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...

  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. Preparative Isolation of Polar Antioxidant Constituents from Abies koreana Using Centrifugal Partition Chromatography Guided by DPPH center dot-HPLC Experiment

    NARCIS (Netherlands)

    Jeon, Je-Seung; Kim, Ji Hoon; Park, Chae Lee; Kim, Chul Young

    2015-01-01

    Preparative separation of antioxidant constituents from the leaves of Abies koreana Wilson (Pinaceae) was performed by centrifugal partition chromatography (CPC) with a two-phase solvent system of ethyl acetate-isopropanol-water (9:1:10, v/v) target-guided by DPPH•-HPLC experiment. In DPPH•-HPLC exp

  4. 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.

  5. 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.

  6. Steam separator modeling for various nuclear reactor transients

    Energy Technology Data Exchange (ETDEWEB)

    Paik, C Y; Mullen, G; Knoess, C; Griffith, P

    1987-06-01

    In a pressurized water reactor steam generator, a moisture separator is used to separate steam and liquid and to insure that essentially dry steam is supplied to the turbine. During a steam line break or combined steam line break plus tube rupture, a number of phenomena can occur in the separator which have no counterparts during steady-state operation. How the separator will perform under these circumstances is important for two reasons, it affects the carry-over of radioactive iodine and the water inventory in the secondary side. This study has as its goal the development of a simple separator model which can be applied to a variety of steam generator for off-design conditions. Experiments were performed using air and water on three different types of centrifugal separators: a cyclone as a generic separator, a Combustion Engineering type stationary swirl vane separator, and a Westinghouse type separator. The cyclone separator system has three stages of separation: first the cyclone, then a gravity separator, and finally a chevron plate separator. The other systems have only a centrifugal separator to isolate the effect of the primary separator. Experiments were also done in MIT blowdown rig, with and without a separator, using steam and water. The separators appear to perform well at flow rates well above the design values as long as the downcomer water level is not high. High downcomer water level rather than high flow rates appear to be the primary cause of degraded performance. Appreciable carry-over from the separator section of a steam generator occurs when the drain lines from three stages of separation are unable to carry off the liquid flow. Failure scenarios of the separator for extreme range of conditions from the quasi-steady state transient to the fast transients are presented. A general model structure and simple separator models are provided.

  7. Influence of the permeability of networked primary Si on the ejection of hypereutectic Al-Si melts by centrifugation

    Science.gov (United States)

    Youn, Ji Won; Jeon, Je-Beom; Park, Jin Man; Seo, Seok Yong; Lim, Jeon Taik; Kim, Suk Jun; Kim, Ki Young

    2017-02-01

    The separation of high purity Si for solar cells from Al-Si alloy melt in the mushy zone was investigated using an advanced centrifugal technique. The efficiency of separating Si, based on the weight ratio of separated Si to Si in alloy melt, was maximized by optimizing the permeability of a porous structure of Si (Si foam.) For the optimization of the permeability, two fundamental microstructure variables, size and the solid fraction of primary Si platelets, were controlled by adjusting the Si content in the melts and the rotation start temperature, respectively. The best separation efficiency (48.3% with 3N purity) was achieved when Si content in melt was 24% and the solid fraction was 8.7%. The melt with 23% Si led to a higher separation efficiency (69.8%) for a solid fraction of 10.4%, but Al sandwiched between the Si platelets resulted in a decrease in the purity to 2N.

  8. Performance analysis of a centrifugal compressor with variable inlet guide vanes

    Institute of Scientific and Technical Information of China (English)

    XIAO Jun; GU Chuangang; SHU Xinwei; GAO Chuang

    2007-01-01

    The flow in a centrifugal compressor stage with variable inlet guide vanes (VIGVs) is investigated by numerical simulation in this paper.Analysis of the performance curves and relative velocity vectograms indicates that performance curves shift toward small flow domain when VIGVs turn positively,and toward large flow domain when VIGVs turn negatively.Stage efficiency drops quickly after work condition enters a small flow domain through the peak efficiency point.Under the circumstance of large setting angles of the guide vanes,there exist obvious flow separations in guide vane passages within wide flow ranges,and back flow regions can be located at the front of splitter suction surfaces under large flow conditions,while under the condition of small flow,flow separations occur on suction surfaces of long blades.

  9. Rapid assessment of sedimentation stability in dispersions using near infrared transmission measurements during centrifugation and oscillatory rheology.

    Science.gov (United States)

    Kuentz, Martin; Röthlisberger, Dieter

    2003-11-01

    We used the LUMiFuge) 114 particle separation analyser to investigate the sedimentation kinetics of bentonite/xanthan gum mixtures through pH 2-7 during centrifugation. This new technique monitors timed near infrared transmission profiles of different samples in the centrifugal field. Statistical analysis of the data then identifies the formulations with minimal clarification tendency. All mixtures were characterised by rotational and oscillatory rheology. Various rheological parameters correlated with the LUMiFuge clarification data, most notably the relaxation exponent, n and loss tangent, tan delta. We devised a combined desirability function for the different mixtures, defining maximal desirability as the minimal values for the two oscillatory parameters. The results matched those of separation analysis in the centrifugal field.We conclude that the experimental design is suitable for selecting formulations with optimal sedimentation stability whether combined with LUMiFuge analysis or oscillatory measurements. The method can be used to screen formulations for optimal long-term stability test performance, with significant potential savings and minimal sedimentation risk after prolonged storage.

  10. 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.

  11. 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.

  12. Neutron diffraction analyses of U-(6-10 wt.%)Mo alloy powders fabricated by centrifugal atomization

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Man [Advanced Fuel Technology Development Division, Korea Atomic Energy Research Institute, 150 Deokjin-dong, Yuseong, Daejeon 305-353 (Korea, Republic of); Ryu, Ho Jin, E-mail: hjryu@kaeri.re.k [Advanced Fuel Technology Development Division, Korea Atomic Energy Research Institute, 150 Deokjin-dong, Yuseong, Daejeon 305-353 (Korea, Republic of); Kim, Ki Hwan; Lee, Don Bae; Lee, Yoon Sang [Advanced Fuel Technology Development Division, Korea Atomic Energy Research Institute, 150 Deokjin-dong, Yuseong, Daejeon 305-353 (Korea, Republic of); Lee, Jeong Soo; Seong, Baek Seok [Neutron Science Division, Korea Atomic Energy Research Institute, 150 Deokjin-dong, Yuseong, Daejeon 305-353 (Korea, Republic of); Kim, Chang Kyu [Advanced Fuel Technology Development Division, Korea Atomic Energy Research Institute, 150 Deokjin-dong, Yuseong, Daejeon 305-353 (Korea, Republic of); Cornen, Marilyne [INSA de Rennes, UMR CNRS 6226 Sciences Chimiques de Rennes/Chimie-Metallurgie, 20 Avenue des Buttes de Coesmes, 35043 Rennes Cedex (France)

    2010-02-15

    Lattice parameters of U-(6-10 wt.%)Mo alloy powders fabricated by a centrifugal atomization technique were measured by neutron diffraction analyses. A micro-segregation of Mo at cell boundaries was observed in the centrifugally atomized U-Mo alloy powders with varying Mo content. Lattice parameters of gamma phases decrease linearly with the increasing Mo content. By separating the overlapped diffraction peaks from cell boundaries and cell interior, lattice parameters and Mo contents of each region were calculated. The Mo content at cell boundaries is about 2-5 at.% lower than that in the cell interior and the lattice parameters for the cell boundaries are higher than those for the cell interior of the atomized U-Mo powder.

  13. Neutron diffraction analyses of U-(6-10 wt.%)Mo alloy powders fabricated by centrifugal atomization

    Science.gov (United States)

    Park, Jong Man; Ryu, Ho Jin; Kim, Ki Hwan; Lee, Don Bae; Lee, Yoon Sang; Lee, Jeong Soo; Seong, Baek Seok; Kim, Chang Kyu; Cornen, Marilyne

    2010-02-01

    Lattice parameters of U-(6-10 wt.%)Mo alloy powders fabricated by a centrifugal atomization technique were measured by neutron diffraction analyses. A micro-segregation of Mo at cell boundaries was observed in the centrifugally atomized U-Mo alloy powders with varying Mo content. Lattice parameters of gamma phases decrease linearly with the increasing Mo content. By separating the overlapped diffraction peaks from cell boundaries and cell interior, lattice parameters and Mo contents of each region were calculated. The Mo content at cell boundaries is about 2-5 at.% lower than that in the cell interior and the lattice parameters for the cell boundaries are higher than those for the cell interior of the atomized U-Mo powder.

  14. 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...

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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...

  1. 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.

  2. 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.

  3. 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.

  4. 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...

  5. Multi-stage mixer-settler planet centrifuge. Preliminary studies on partition of macromolecules with organic-aqueous and aqueous-aqueous two-phase solvent systems.

    Science.gov (United States)

    Ito, Y; Zhang, T Y

    1988-03-11

    A rotary-seal-free planetary centrifuge holds a separation column which consists of multiple partition units (ca. 200) connected in series with transfer tubes. In the cavity of each partition unit the transfer tube extends to form a mixer which vibrates to stir the contents under an oscillating force field generated by the planetary motion of the centrifuge. Consequently, solutes locally introduced at the inlet of the column are subjected to an efficient partition process in each partition unit and separated according to their partition coefficients. The mixer tube equipped with a flexible silicone rubber joint was found to produce excellent results for partition with viscous polymer phase systems. The capability of the method was demonstrated on separation of cytochrome c and lysozyme using a PEG-aqueous dibasic potassium phosphate-aqueous two-phase solvent system.

  6. Severe Hemolysis in a Patient With Erythrocytosis During Coupled Plasma Filtration Adsorption Therapy Was Prevented by Changing From Membrane-Based Technique to a Centrifuge-Based One.

    Science.gov (United States)

    Fan, Rong; Wu, Buyun; Kong, Ling; Gong, Dehua

    2016-01-01

    Coupled plasma filtration adsorption (CPFA) usually adopts membrane to separate plasma from blood. Here, we reported a case with erythrocytosis experienced severe hemolysis and membrane rupture during CPFA, which was avoided by changing from membrane-based technique to a centrifuge-based one. A 66-year-old man was to receive CPFA for severe hyperbilirubinemia (total bilirubin 922 μmol/L, direct bilirubin 638 μmol/L) caused by obstruction of biliary tract. He had erythrocytosis (hemoglobin 230 g/L, hematocrit 0.634) for years because of untreated tetralogy of Fallot. Severe hemolysis and membrane rupture occurred immediately after blood entering into the plasma separator even at a low flow rate (50 mL/min) and persisted after changing a new separator. Finally, centrifugal plasma separation technique was used for CPFA in this patient, and no hemolysis occurred. After 3 sessions of CPFA, total bilirubin level decreased to 199 μmol/L with an average decline by 35% per session. Thereafter, the patient received endoscopic biliary stent implantation, and total bilirubin level returned to nearly normal. Therefore, centrifugal-based plasma separation can also be used in CPFA and may be superior to a membrane-based one in patients with hyperviscosity.

  7. RESEARCH AND DEVELOPMENT OF AN INTEGRAL SEPARATOR FOR A CENTRIFUGAL GAS PROCESSING FACILITY

    Energy Technology Data Exchange (ETDEWEB)

    LANCE HAYS

    2007-02-27

    A COMPACT GAS PROCESSING DEVICE WAS INVESTIGATED TO INCREASE GAS PRODUCTION FROM REMOTE, PREVIOUSLY UN-ECONOMIC RESOURCES. THE UNIT WAS TESTED ON AIR AND WATER AND WITH NATURAL GAS AND LIQUID. RESULTS ARE REPORTED WITH RECOMMENDATIONS FOR FUTURE WORK.

  8. HRS Separator

    CERN Multimedia

    2016-01-01

    Footage of the 90 and 60 degree ISOLDE HRS separator magnets in the HRS separator zone. In the two vacuum sectors HRS20 and HRS30 equipment such as the HRS slits SL240, the HRS faraday cup FC300 and wiregrid WG210 can be spotted. Vacuum valves, turbo pumps, beamlines, quadrupoles, water and compressed air connections, DC and signal cabling can be seen throughout the video. The HRS main and user beamgate in the beamline between MAG90 and MAG60 and its switchboxes as well as all vacuum bellows and flanges are shown. Instrumentation such as the HRS scanner unit 482 / 483, the HRS WG470 wiregrid and slits piston can be seen. The different quadrupoles and supports are shown as well as the RILIS guidance tubes and installation at the magnets and the different radiation monitors.

  9. GPS Separator

    CERN Multimedia

    2016-01-01

    Footage of the 70 degree ISOLDE GPS separator magnet MAG70 as well as the switchyard for the Central Mass and GLM (GPS Low Mass) and GHM (GPS High Mass) beamlines in the GPS separator zone. In the GPS20 vacuum sector equipment such as the long GPS scanner 482 / 483 unit, faraday cup FC 490, vacuum valves and wiregrid piston WG210 and WG475 and radiation monitors can also be seen. Also the RILIS laser guidance and trajectory can be seen, the GPS main beamgate switch box and the actual GLM, GHM and Central Beamline beamgates in the beamlines as well as the first electrostatic quadrupoles for the GPS lines. Close up of the GHM deflector plates motor and connections and the inspection glass at the GHM side of the switchyard.

  10. The carbon fiber development for uranium centrifuges: a Brazilian cooperative research

    Energy Technology Data Exchange (ETDEWEB)

    Queiroz, Paulo Cesar Beltrao de, E-mail: p.queiroz@ctmsp.mar.mil.b [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), Sao Paulo, SP (Brazil); Zouain, Desiree Moraes, E-mail: dmzouain@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2009-07-01

    This paper analyzes both the carbon fiber-based development for uranium centrifuges and the research project that supports its development effort over time. The carbon fiber-based engineering properties make it a valuable supply for high technologic products. Nevertheless, its fabrication occurs only in few developed countries and there is no production in Brazil. In addition, the carbon fiber-based products have dual applications: they can be used by the civilian and military industry. Therefore, there are international restrictions related to its use and applications that justify the internal development. Moreover, the Brazilian Navy centrifuges for uranium enrichment were developed using carbon-fiber which contains polyacrylonitrile (PAN) as an imported raw material. The PAN properties of low weight, high tensile strength increase the isotopic separation efficiency. The Brazilian financial scenario surrounded by the international uncertain economy shows that combined creative project solutions are more effective. Therefore, the Navy's Technological Center in Sao Paulo (CTMSP), the University of Campinas (UNICAMP), the University of Sao Paulo (USP), the RADICIFIBRAS Company, and the Brazilian FINEP agency, which is responsible for the project financial support, established a partnership aiming the development of a domestic PAN-based carbon fiber industry. The innovative project solutions adopted and the results of this partnership are presented here. (author)

  11. Design and optimization of a single stage centrifugal compressor for a solar dish-Brayton system

    Science.gov (United States)

    Wang, Yongsheng; Wang, Kai; Tong, Zhiting; Lin, Feng; Nie, Chaoqun; Engeda, Abraham

    2013-10-01

    According to the requirements of a solar dish-Brayton system, a centrifugal compressor stage with a minimum total pressure ratio of 5, an adiabatic efficiency above 75% and a surge margin more than 12% needs to be designed. A single stage, which consists of impeller, radial vaned diffuser, 90° crossover and two rows of axial stators, was chosen to satisfy this system. To achieve the stage performance, an impeller with a 6:1 total pressure ratio and an adiabatic efficiency of 90% was designed and its preliminary geometry came from an in-house one-dimensional program. Radial vaned diffuser was applied downstream of the impeller. Two rows of axial stators after 90° crossover were added to guide the flow into axial direction. Since jet-wake flow, shockwave and boundary layer separation coexisted in the impeller-diffuser region, optimization on the radius ratio of radial diffuser vane inlet to impeller exit, diffuser vane inlet blade angle and number of diffuser vanes was carried out at design point. Finally, an optimized centrifugal compressor stage fulfilled the high expectations and presented proper performance. Numerical simulation showed that at design point the stage adiabatic efficiency was 79.93% and the total pressure ratio was 5.6. The surge margin was 15%. The performance map including 80%, 90% and 100% design speed was also presented.

  12. Numerical Flow Simulation in a Centrifugal Pump at Design and Off-Design Conditions

    Directory of Open Access Journals (Sweden)

    K. W. Cheah

    2007-01-01

    Full Text Available The current investigation is aimed to simulate the complex internal flow in a centrifugal pump impeller with six twisted blades by using a three-dimensional Navier-Stokes code with a standard k-ε two-equation turbulence model. Different flow rates were specified at inlet boundary to predict the characteristics of the pump. A detailed analysis of the results at design load, Qdesign, and off-design conditions, Q = 0.43 Qdesign and Q = 1.45 Qdesign, is presented. From the numerical simulation, it shows that the impeller passage flow at design point is quite smooth and follows the curvature of the blade. However, flow separation is observed at the leading edge due to nontangential inflow condition. The flow pattern changed significantly inside the volute as well, with double vortical flow structures formed at cutwater and slowly evolved into a single vortical structure at the volute diffuser. For the pressure distribution, the pressure increases gradually along streamwise direction in the impeller passages. When the centrifugal pump is operating under off-design flow rate condition, unsteady flow developed in the impeller passage and the volute casing.

  13. Flow control of a centrifugal fan in a commercial air conditioner

    Science.gov (United States)

    Kim, Jiyu; Bang, Kyeongtae; Choi, Haecheon; Seo, Eung Ryeol; Kang, Yonghun

    2015-11-01

    Air-conditioning fans require a low noise level to provide user comfort and quietness. The aerodynamic noise sources are generated by highly unsteady, turbulent structures near the fan blade. In this study, we investigate the flow characteristics of a centrifugal fan in an air-conditioner indoor unit and suggest control ideas to develop a low noise fan. The experiment is conducted at the operation condition where the Reynolds number is 163000 based on the blade tip velocity and chord length. Intermittent separation occurs at the blade leading edge and thus flow significantly fluctuates there, whereas vortex shedding occurs at the blade trailing edge. Furthermore, the discharge flow observed in the axial plane near the shroud shows low-frequency intermittent behaviors, resulting in high Reynolds stresses. To control these flow structures, we modify the shapes of the blade leading edge and shroud of the centrifugal fan and obtain noise reduction. The flow characteristics of the base and modified fans will be discussed. Supported by 0420-20130051.

  14. TWO-DIMENSIONAL PARTICLE IMAGE VELOCIMETRY(PIV) MEASUREMENTS IN A TRANSPARENT CENTRIFUGAL PUMP

    Institute of Scientific and Technical Information of China (English)

    Yang Hua; Gu Chuangang; Wang Tong

    2005-01-01

    A special transparent centrifugal pump is designed. Detailed optical measurements of the flow inside the rotating passages of a five-bladed shroud centrifugal pump impeller have been performed by using two-dimensional particle image velocimetry (PIV). The flow is surveyed at three load conditions qv/qνd = 0.4, qν/qνd = 1.0, qν/qνd = 1.5, respectively. As a result, phase averaged PIV velocity vector maps on three planes between hub and shroud of the impeller are presented. At design load, the mean field of relative velocity is predominantly vane congruent, showing well-behaved flow without separation. The distributions of the relative velocity on different plane along the pump shaft are very different and there is always a low velocity zone near the pressure-side of the blade at both low and design flow rate, but the low-velocity-zone at the low flow rate is much larger than that at the design one. The study demonstrates that the PIV technique is efficient in providing reliable and detailed velocity data over a full impeller passage.

  15. Impact energy analysis of turbulent water sprays for continuous centrifugal concentration

    Institute of Scientific and Technical Information of China (English)

    PEN Nan-qi; CHEN Lu-zheng; XIONG Da-he

    2009-01-01

    A SLon full-scale continuous centrifugal concentrator was used to reconcentrate hematite from a high gradient magnetic separation concentrate to study the effect of impact angle, concentrate mass and drum rotation speed on the impact energy of turbulent water sprays for continuous centrifugal concentration, under conditions of feed volume flow rate around 9 m3/h, feed solid concentration of 25% - 35% and reciprocating velocity of water sprays at 0. 05 m/s. The results indicate that a mimmal critical impact energy is required in the water sprays for achieving continuous concentration of the concentrator; an unfitted impact angle reduces the impact ffciency, and the highest impact efficiency of 0. 6416 is found at the mpact angle of 60°; the increase in concentrate mass leads to an increase in impact energy, and the highest impact efficiency is maintained when the concentrate mass varies in the range of 0. 44 -0. 59 kg/s; when the concentrate mass and the pressure of water sprays are kept at around 0. 45 kg/s and in the range of 0. 4 -0. 6 MPa respectively, the impact energy increases proportionally with the increase of drum rotation speed.

  16. Simulation and analysis of multi-stage centrifugal fractional extraction process of 4-nitrobenzene glycine enantiomers☆

    Institute of Scientific and Technical Information of China (English)

    Ping Wen; Kewen Tang; Jicheng Zhou; Panliang Zhang

    2015-01-01

    Based on the interfacial ligand exchange model and the law of conservation of mass, the multi-stage enantioselective liquid–liquid extraction model has been established to analyze and discuss on multi-stage centrifugal fractional extraction process of 4-nitrobenzene glycine (PGL) enantiomers. The influence of phase ratio, extractant concentra-tion, and PF6−concentration on the concentrations of enantiomers in the extract and raffinate was investigated by experiment and simulation. A good agreement between model and experiment was obtained. On this basis, the influence of many parameters such as location of stage, concentration levels, extractant excess, and number of stages on the symmetric separation performance was simulated. The optimal location of feed stage is the middle of fractional extraction equipment. The feed flow must satisfy a restricted relationship on flow ratios and the liquid throughout of centrifugal device. For desired purity specification, the required flow ratios decrease with extractant concentration and increase with PF6−concentration. When the number of stages is 18 stages at extractant excess of 1.0 or 14 stages at extractant excess of 2.0, the eeeq (equal enantiomeric excess) can reach to 99%.

  17. Mechanism of Gas Intrusion into Molten Metal during Horizontal Centrifugal Casting

    Institute of Scientific and Technical Information of China (English)

    NI Feng; ZHANG Xhan-ling; YANG Di-xin; BI Xiao-qin; ZHANG Yong-zhen

    2004-01-01

    A mechanism of gas intrusion into molten metal during horizontal centrifugal casting was introduced .Based upon this concept, a special pouring method was suggested ,which can effectively prevent the pinhole defects in horizontal centrifugal castings.

  18. Centrifugal Model Tests on Railway Embankments of Expansive Soils

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Based on the centrifugal model tests on railway embankments of expansive soil in Nanning-Kunming railway,the author studied several embankments under different physical conditions. The stress and strain states and settlement of the embankments were analyzed, and the obtained results can be used as a reference to field construction.

  19. Liquid egg white pasteurization using a centrifugal UV irradiator

    Science.gov (United States)

    Studies are lacking on UV nonthermal pasteurization of liquid egg white (LEW). The objective of this study was to inactivate Escherichia coli using a UV irradiator that centrifugally formed a thin film of LEW on the inside of a rotating cylinder. The LEW was inoculated with E. coli K12 to approximat...

  20. DEMONSTRATION BULLETIN: THE PLASMA CENTRIFUGAL FURNACE RETECH, INC.

    Science.gov (United States)

    The plasma centrifugal furnace is a thermal technology which uses the heat generated from a plasma torch to decontaminate metal and organic contaminated waste. This is accomplished by melting metal-bearing solids and, in the process, thermally destroying organic contaminants. The...

  1. Pasteurization of grapefruit juice using a centrifugal ultraviolet light irradiator

    Science.gov (United States)

    The pharmaceutical industry uses UV irradiators to inactivate viruses in liquids without heat. The penetration depth of UV in some liquids, such as serum plasma, can be short. To overcome this, very thin films may be produced by centrifugal force, small diameter tubing, or other means. Many liquid f...

  2. Latex micro-balloon pumping in centrifugal microfluidic platforms.

    Science.gov (United States)

    Aeinehvand, Mohammad Mahdi; Ibrahim, Fatimah; Harun, Sulaiman Wadi; Al-Faqheri, Wisam; Thio, Tzer Hwai Gilbert; Kazemzadeh, Amin; Madou, Marc

    2014-03-01

    Centrifugal microfluidic platforms have emerged as point-of-care diagnostic tools. However, the unidirectional nature of the centrifugal force limits the available space for multi-step processes on a single microfluidic disc. To overcome this limitation, a passive pneumatic pumping method actuated at high rotational speeds has been previously proposed to pump liquid against the centrifugal force. In this paper, a novel micro-balloon pumping method that relies on elastic energy stored in a latex membrane is introduced. It operates at low rotational speeds and pumps a larger volume of liquid towards the centre of the disc. Two different micro-balloon pumping mechanisms have been designed to study the pump performance at a range of rotational frequencies from 0 to 1500 rpm. The behaviour of the micro-balloon pump on the centrifugal microfluidic platforms has been theoretically analysed and compared with the experimental data. The experimental data show that the developed pumping method dramatically decreases the required rotational speed to pump liquid compared to the previously developed pneumatic pumping methods. It also shows that within a range of rotational speed, a desirable volume of liquid can be stored and pumped by adjusting the size of the micro-balloon.

  3. Pasteurization of Grapefruit Juice using a Centrifugal Ultraviolet Light Device

    Science.gov (United States)

    The pharmaceutical industry uses UV devices to nonthermally inactivate viruses in liquids. To overcome the low penetration depth of UV in some liquids, such as serum plasma, thin films are formed by centrifugal force. Liquid foods also have low UV penetration depths. Studies are lacking on nontherma...

  4. 14 CFR 35.35 - Centrifugal load tests.

    Science.gov (United States)

    2010-01-01

    ... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: PROPELLERS Tests and Inspections § 35.35 Centrifugal load tests. The applicant must demonstrate that a propeller complies with paragraphs (a), (b) and (c) of this section without evidence of...

  5. Application of antioxidants and centrifugation for cryopreservation of boar spermatozoa.

    Science.gov (United States)

    Zhang, Wei; Yi, Kangle; Chen, Chao; Hou, Xiaofeng; Zhou, Xu

    2012-06-01

    Although cryopreserved boar semen has been available since 1975, a major breakthrough in commercial application has not yet occurred due to the high susceptibility of boar spermatozoa to damage during cryopreservation and the complicated process required for deep freezing. In recent years, the application of antioxidants during the cryopreservation of boar semen has been the subject of considerable research aimed at improving the quality of post-thaw semen. Centrifugation is necessary before using cryopreservation protocols for freezing boar spermatozoa. Studies of the effect of different centrifugation regimens on boar sperm recovery, yield and cryosurvival have made significant contributions. Therefore this review elucidates results of recent applications of various antioxidants and centrifugation regimens used in efforts to improve cryopreservation of boar spermatozoa. This review is intended to enhance understanding of the roles of these antioxidants and centrifugation regimens with respect to mechanisms that increase resistance to cryodamage of boar spermatozoa. In addition, the discussion addresses the need for developing an objective evaluation of effectiveness and estimating the prospect of application of new techniques for the cryopreservation of boar semen and its use in artificial insemination.

  6. Vibratory centrifuge for the dewatering of coal sludge

    Energy Technology Data Exchange (ETDEWEB)

    Schiele, H.; Schlebusch, L.

    1981-03-03

    A vibratory centrifuge for the dewatering of coal sludge, washed small coal or slack which comprises a revolvable conical screen which has a diameter that increases towards its discharge end. The conical screen is vibratable in an axial direction and includes radial steps each having a height of at least 20 mm to rearrangement or loosen the material in the zone of each step.

  7. Synthesis and Analytical Centrifugation of Magnetic Model Colloids

    NARCIS (Netherlands)

    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 s

  8. Numerical Simulation and Cold Modeling experiments on Centrifugal Casting

    Science.gov (United States)

    Keerthiprasad, Kestur Sadashivaiah; Murali, Mysore Seetharam; Mukunda, Pudukottah Gopaliengar; Majumdar, Sekhar

    2011-02-01

    In a centrifugal casting process, the fluid flow eventually determines the quality and characteristics of the final product. It is difficult to study the fluid behavior here because of the opaque nature of melt and mold. In the current investigation, numerical simulations of the flow field and visualization experiments on cold models have been carried out for a centrifugal casting system using horizontal molds and fluids of different viscosities to study the effect of different process variables on the flow pattern. The effects of the thickness of the cylindrical fluid annulus formed inside the mold and the effects of fluid viscosity, diameter, and rotational speed of the mold on the hollow fluid cylinder formation process have been investigated. The numerical simulation results are compared with corresponding data obtained from the cold modeling experiments. The influence of rotational speed in a real-life centrifugal casting system has also been studied using an aluminum-silicon alloy. Cylinders of different thicknesses are cast at different rotational speeds, and the flow patterns observed visually in the actual castings are found to be similar to those recorded in the corresponding cold modeling experiments. Reasonable agreement is observed between the results of numerical simulation and the results of cold modeling experiments with different fluids. The visualization study on the hollow cylinders produced in an actual centrifugal casting process also confirm the conclusions arrived at from the cold modeling experiments and numerical simulation in a qualitative sense.

  9. Centrifugally driven microfluidic disc for detection of chromosomal translocations

    DEFF Research Database (Denmark)

    Brøgger, Anna Line; Kwasny, Dorota; Bosco, Filippo G.

    2012-01-01

    and prognosis of patients. In this work we demonstrate a novel, centrifugally-driven microfluidic system for controlled manipulation of oligonucleotides and subsequent detection of chromosomal translocations. The device is fabricated in the form of a disc with capillary burst microvalves employed to control...

  10. Centrifuge modelling of rigid piles in soft clay

    DEFF Research Database (Denmark)

    Klinkvort, R.T.; Poder, M.; Truong, P.;

    2016-01-01

    of this study is to employ centrifuge modelling in order to derive experimental p-y curves for rigid piles embedded in over-consolidated soft clay. A kaolin clay sample was prepared and pre-consolidated by applying a constant pressure at the soil surface, while different over-consolidation ratios were achieved...

  11. Ocular torsion before and after 1 hour centrifugation

    NARCIS (Netherlands)

    Groen, E.; Graaf, B. de; Bles, W.; Bos, J.E.

    1996-01-01

    To assess a possible otolith contribution to effects observed following prolonged expo-sure to hyper gravity, we used video-oculography to measure ocular torsion during static and dynamic conditions of lateral body tilt (roll) before and after one hour of centrifugation with a Gx-load of 3G. Static

  12. Extraction of cocoa proanthocyanidins and their fractionation by sequential centrifugal partition chromatography and gel permeation chromatography.

    Science.gov (United States)

    Pedan, Vasilisa; Fischer, Norbert; Rohn, Sascha

    2016-08-01

    Cocoa beans contain secondary metabolites ranging from simple alkaloids to complex polyphenols with most of them believed to possess significant health benefits. The increasing interest in these health effects has prompted the need to develop techniques for their extraction, fractionation, separation, and analysis. This work provides an update on analytical procedures with a focus on establishing a gentle extraction technique. Cocoa beans were finely ground to an average particle size of centrifugal partition chromatography (SCPC) and gel permeation column chromatography using Sephadex LH-20. For SCPC, a two-phase solvent system consisting of ethyl acetate/n-butanol/water (4:1:5, v/v/v) was successfully applied for the separation of theobromine, caffeine, and representatives of the two main phenolic compound classes flavan-3-ols and flavonols. Gel permeation chromatography on Sephadex LH-20 using a stepwise elution sequence with aqueous acetone has been shown for effectively separating individual flavan-3-ols. Separation was obtained for (-)-epicatechin, proanthocyanidin dimer B2, trimer C1, and tetramer cinnamtannin A2. The purity of alkaloids and phenolic compounds was determined by HPLC analysis and their chemical identity was confirmed by mass spectrometry.

  13. Comparative analysis of discrete exosome fractions obtained by differential centrifugation

    Directory of Open Access Journals (Sweden)

    Dennis K. Jeppesen

    2014-11-01

    Full Text Available 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 carcinoma FL3 cells. The fractions were evaluated by nanoparticle tracking analysis (NTA, total protein quantification and immunoblotting for CD81, TSG101, syntenin, VDAC1 and calreticulin. Results: NTA revealed the lowest background particle count in Dulbecco's Modified Eagle's Medium media devoid 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 and composition of the obtained fractions. In addition, HEK293 and FL3 vesicles displayed marked differences in sedimentation characteristics. Exosomes were pelleted already at 33,000×g, a g-force which also removed most contaminating microsomes. Optimal vesicle-to-protein yield was obtained at 67,000×g for HEK293 cells but 100,000×g for FL3 cells. Relative expression of exosomal markers (TSG101, CD81, syntenin suggested presence of exosome subpopulations with variable sedimentation characteristics. Conclusions: Specific g-force/k factor usage during differential centrifugation greatly influences the purity and yield of exosomes. The vesicle sedimentation profile differed between the 2 cell lines.

  14. 40 CFR Appendix - Alternative Organic HAP Emissions Limits for Open Molding, Centrifugal Casting, and SMC...

    Science.gov (United States)

    2010-07-01

    ... Limits for Open Molding, Centrifugal Casting, and SMC Manufacturing Operations Where the Standards Are..., Table 5 Alternative Organic HAP Emissions Limits for Open Molding, Centrifugal Casting, and SMC... casting—CR/HS 3,4 A vent system that moves heated air through the mold 27 lb/ton. 8. Centrifugal...

  15. A novel technique using the Hendrickx centrifuge for extracting winter sporangia of Synchytrium endobioticum from soil

    NARCIS (Netherlands)

    Wander, J.G.N.; Berg, van den W.; Boogert, van den P.H.J.F.; Lamers, J.G.; Leeuwen, van G.C.M.; Hendrickx, G.; Bonants, P.J.M.

    2007-01-01

    A zonal centrifugation method, known as the Hendrickx centrifuge technique, was tested for routine detection of winter sporangia of Synchytrium endobioticum in soil. In four experiments the ability of the Hendrickx centrifuge to extract the sporangia from soil was compared with a method used by the

  16. 77 FR 65360 - Grant of Authority for Subzone Status (Centrifugal and Submersible Pumps); Auburn, NY

    Science.gov (United States)

    2012-10-26

    ... Foreign-Trade Zones Board Grant of Authority for Subzone Status (Centrifugal and Submersible Pumps... subzone at the centrifugal and submersible pump manufacturing and warehousing facilities of Xylem Water... activity related to the manufacturing of centrifugal and submersible pumps and related controllers at...

  17. Research on Three-Dimensional Unsteady Turbulent Flow in Multistage Centrifugal Pump and Performance Prediction Based on CFD

    Directory of Open Access Journals (Sweden)

    Zhi-jian Wang

    2013-01-01

    Full Text Available The three-dimensional flow physical model of any stage of the 20BZ4 multistage centrifugal pump is built which includes inlet region, impeller flow region, guide-vane flow region and exit region. The three-dimensional unsteady turbulent flow numerical model is created based on Navier-Stoke solver and standard k-ε turbulent equations. The method of multireference frame (MRF and SIMPLE algorithm are used to simulate the flow in multistage centrifugal pump based on FLUENT software. The distributions of relative velocity, absolute velocity, static pressure, and total pressure in guide vanes and impellers under design condition are analyzed. The simulation results show that the flow in impeller is mostly uniform, without eddy, backflow, and separation flow, and jet-wake phenomenon appears only along individual blades. There is secondary flow at blade end and exit of guide vane. Due to the different blade numbers of guide vane and impeller, the total pressure distribution is asymmetric. This paper also simulates the flow under different working conditions to predict the hydraulic performances of centrifugal pump and external characteristics including flow-lift, flow-shaft power, and flow-efficiency are attained. The simulation results are compared with the experimental results, and because of the mechanical losses and volume loss ignored, there is a little difference between them.

  18. Investigation of the Stage Performance and Flow Fields in a Centrifugal Compressor with a Vaneless Diffuser

    Directory of Open Access Journals (Sweden)

    Ahti Jaatinen-Värri

    2014-01-01

    Full Text Available The effect of the width of the vaneless diffuser on the stage performance and flow fields of a centrifugal compressor is studied numerically and experimentally. The diffuser width is varied by reducing the diffuser flow area from the shroud side (i.e., pinching the diffuser. Seven different diffuser widths are studied with numerical simulation. In the modeling, the diffuser width b/b2 is varied within the range 1.00 to 0.50. The numerical results are compared with results obtained in previous studies. In addition, two of the diffusers are further investigated with experimental measurement. The main finding of the work is that the pinch reduces losses in the impeller associated with the tip-clearance flow. Furthermore, it is shown that a too large width reduction causes the flow to accelerate excessively, resulting in a highly nonuniform flow field and flow separation near the shroud.

  19. Performance Enhancement of Dual-Inlet Centrifugal Blower by Optimal Design of Splitter

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Sung; Jang, Choon Man [Korea Institute of Construction Technology, Goyang (Korea, Republic of)

    2014-12-15

    The shape of an impeller splitter for a dual-inlet centrifugal blower was optimized to enhance the blower performance. Two design variable, the normalized chord and pitch of a splitter, were used to evaluate the blower performance and internal flow fields based on the three-dimensional flow analysis. The blower performance obtained using this numerical simulation had a maximum error of 4 percent compared to that in an experiment at the design flow condition. The shape optimization of the splitter successfully increased the blower efficiency and pressure by 3.65 and 1.14 percent compared to the reference values. The blower performance was increased by reducing the flow separation near the blade suction surface by optimizing the shape of the splitter, which produced a pressure increase at the outlet of the volute casing.

  20. Centrifugal partition chromatography as a tool for preparative purification of pea albumin with enhanced yields.

    Science.gov (United States)

    Bérot, Serge; Le Goff, Elisabeth; Foucault, Alain; Quillien, Laurence

    2007-01-15

    A new procedure including the use of centrifugal partition chromatography (CPC) is proposed to purify PA1b and its isoforms. These pea (Pisum sativum L.) seed proteins are toxic against weevils and can be used as an environment-friendly insecticide. CPC was applied to a whole albumin fraction prepared from pea flour. The butanol:aqueous TFA system used in CPC allowed the separation of PA1b from other albumins and a degree of purification above 95%. Compared to analytical procedures based on methanol extraction, anion exchange and then reversed-phase chromatography (RPC), CPC recovered PA1b in much better yield, which is indispensable for large-scale purification of a biodegradable insecticide.

  1. Magnetron sputtering of copper on thermosensitive polymer materials of the gas centrifuge rotors

    Science.gov (United States)

    Borisevich, V.; Senchenkov, S.; Titov, D.

    2016-09-01

    Magnetron sputtering is the well-known and widely-used deposition technique for coating versatile high-quality and well-adhered films. However, the technology has some limitations, caused by high temperatures on the coating surface. The paper is devoted to the experimental development of a process of magnetron sputtering of copper on a surface coated with a thermosensitive polymer made of carbon fiber with epoxide binder. This process is applied for balancing a rotor of a gas centrifuge for isotope separation. The optimum operating parameters of the process are found and discussed. They were in quantitative agreement with data obtained by means of non-stationary modeling based on a global description of plasma in the typical geometry of the magnetron discharges obtained in independent research. The structure of the resulting layer is investigated.

  2. EFFECTS OF SPLITTER BLADES ON THE LAW OF INNER FLOW WITHIN CENTRIFUGAL PUMP IMPELLER

    Institute of Scientific and Technical Information of China (English)

    YUAN Shouqi; ZHANG Jinfeng; YUAN Jianping; HE Youshi; FU Yuedeng

    2007-01-01

    Analysis on the inner flow field of a centrifugal pump impeller with splitter blades is carried out by numerical simulation. Based on this analysis, the principle of increasing pump head and efficiency are discussed. New results are obtained from the analysis of turbulence kinetic energy and relative velocity distribution: Firstly, unreasonable length or deviation design of the splitter blades may cause great turbulent fluctuation in impeller channel, which has a great effect on the stability of impeller outlet flow; Secondly, it is found that the occurrence of flow separation can be decreased or delayed with splitter blades from the analysis of blade loading; Thirdly, the effect of splitter blades on reforming the structure of "jet-wake" is explained from the relative velocity distribution at different flow cross-sections, which shows the flow process in the impeller. The inner flow analysis verifies the results of performance tests results and the PIV test.

  3. Large-scale and highly efficient synthesis of micro- and nano-fibers with controlled fiber morphology by centrifugal jet spinning for tissue regeneration.

    Science.gov (United States)

    Ren, Liyun; Pandit, Vaibhav; Elkin, Joshua; Denman, Tyler; Cooper, James A; Kotha, Shiva P

    2013-03-21

    PLLA fibrous tissue scaffolds with controlled fiber nanoscale surface roughness are fabricated with a novel centrifugal jet spinning process. The centrifugal jet spinning technique is a highly efficient synthesis method for micron- to nano-sized fibers with a production rate up to 0.5 g min(-1). During the centrifugal jet spinning process, a polymer solution jet is stretched by the centrifugal force of a rotating chamber. By engineering the rheological properties of the polymer solution, solvent evaporation rate and centrifugal force that are applied on the solution jet, polyvinylpyrrolidone (PVP) and poly(l-lactic acid) (PLLA) composite fibers with various diameters are fabricated. Viscosity measurements of polymer solutions allowed us to determine critical polymer chain entanglement limits that allow the generation of continuous fiber as opposed to beads or beaded fibers. Above a critical concentration at which polymer chains are partially or fully entangled, lower polymer concentrations and higher centrifugal forces resulted in thinner fibers. Etching of PVP from the PLLA-PVP composite fibers doped with increasing PVP concentrations yielded PLLA fibers with increasing nano-scale surface roughness and porosity, which increased the fiber hydrophilicity dramatically. Scanning electron micrographs of the etched composite fibers suggest that PVP and PLLA were co-contiguously phase separated within the composite fibers during spinning and nano-scale roughness features were created after the partial etching of PVP. To study the tissue regeneration efficacy of the engineered PLLA fiber matrix, human dermal fibroblasts are used to simulate partial skin graft. Fibers with increased PLLA surface roughness and porosity demonstrated a trend towards higher cell attachment and proliferation.

  4. 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.

  5. The enhanced ASDEX Upgrade pellet centrifuge launcher

    Science.gov (United States)

    Plöckl, B.; Lang, P. T.

    2013-10-01

    Pellets played an important role in the program of ASDEX Upgrade serving both for investigations on efficient particle fuelling and high density scenarios but also for pioneering work on Edge Localised Mode (ELM) pacing and mitigation. Initially designed for launching fuelling pellets from the magnetic low field side, the system was converted already some time ago to inject pellets from the magnetic high field side as much higher fuelling efficiency was found using this configuration. In operation for more than 20 years, the pellet launching system had to undergo a major revision and upgrading, in particular of its control system. Furthermore, the control system installed adjacent to the launcher had to be transferred to a more distant location enforcing a complete galvanic separation from torus potential and a fully remote control solution. Changing from a hybrid system consisting of PLC S5/S7 and some hard wired relay control to a state of the art PLC system allowed the introduction of several new operational options enabling more flexibility in the pellet experiments. This article describes the new system architecture of control hardware and software, the operating procedure, and the extended operational window. First successful applications for ELM pacing and triggering studies are presented as well as utilization for the development of high density scenarios.

  6. Mild separation system for olive oil: quality evaluation and pilot plant design

    Directory of Open Access Journals (Sweden)

    Francesco Genovese

    2013-09-01

    Full Text Available The entire process of olive oil extraction involves the breakage of olive fruits to obtain a paste, the kneading of the paste, a centrifugation, and a further cleaning, performed by a disc stack centrifuge, to separate the residual water. In this research, in order to evaluate the effect of final centrifugal separation on olive oil quality and to both define and design the settings of a innovative separation system, olive oil was separated off from water using an accelerated separation process, tested in comparison with a disc centrifuge. The laboratory plant used for the trials was constituted by a twin cylindrical separator equipped with 4 variable frequency inverters, in order to regulate the fluid flow rates in the plant. Oil samples were collected during the trials to evaluate the influence of the proposed innovative process on oil quality; measuring some parameters as free acidity, peroxides (PV, specific extinction coefficients K232 and K270, chlorophylls , carotenoids, total polyphenols (POL and turbidity. Results showed statistically significant differences (p-values<0.05 in some parameters as POL, PV, and ultraviolet absorption K232 and K270.

  7. ElectroCore separator for particulate air emissions

    Energy Technology Data Exchange (ETDEWEB)

    Easom, B.H.; Smolensky, L.A.; Wysk, S.R.; Altman, R.F.; Olen, K.R.

    1998-07-01

    Coal combustion in fossil energy power systems releases trace amounts of chemical elements identified in the Clean Air Act Amendments of 1990 as hazardous air pollutants (HAPs). Most HAPs exist as solid phase particulate matter and are emitted to the atmosphere in this form. To reduce the emissions of these HAPs, a novel, high efficiency particle collection system known as the ElectroCore is being developed. The concept involves placing a high efficiency particle separator downstream of an underperforming electrostatic precipitator (ESP) that strips the particles from the incoming flow and returns them, along with a small amount of recirculation flow, back to the inlet of the ESP. The main component of the system is the ElectroCore separator. Its design is based on the mechanical Core Separator developed by LSR as a high efficiency centrifugal separator. Enhancing the Core Separator by adding an electrical field improves the separation efficiency of particles in the sub-micron range which is the range where centrifugal separation is ineffective. In the combined system, the centrifugal forces operating on the particles augmented by electrostatic forces so that the ElectroCore has high separation efficiency for particles of all sizes. Field tests have shown that the ElectroCore operating downstream of an underperforming ESP can reduce the particulate emission rate to below 4.3 ng/J (0.01 lb{sub m}/million Btu) even for ESPs with emission rates as high as 260 ng/J (0.6 lb{sub m}/million Btu). The ElectroCore system can perform with most all coal ranks or residual fuel oils (RFO) and has a potentially low capital cost.

  8. Environmental and centrifugal factors influencing the visco-elastic properties of oral biofilms in vitro.

    Science.gov (United States)

    Peterson, Brandon W; Busscher, Henk J; Sharma, Prashant K; van der Mei, Henny C

    2012-01-01

    Centrifugal compaction causes changes in the surface properties of bacterial cells. It has been shown previously that the surface properties of planktonic cells change with increasing centrifugal compaction. This study aimed to analyze the influences of centrifugal compaction and environmental conditions on the visco-elastic properties of oral biofilms. Biofilms were grown out of a layer of initially adhering streptococci, actinomyces or a combination of these. Different uni-axial deformations were induced on the biofilms and the load relaxations were measured over time. Linear-Regression-Analysis demonstrated that both the centrifugation coefficient for streptococci and induced deformation influenced the percentage relaxation. Centrifugal compaction significantly influenced relaxation only upon compression of the outermost 20% of the biofilm (p centrifugal compaction of initially adhering, centrifuged bacteria extend to the visco-elastic properties of biofilms, indicating that the initial bacterial layer influences the structure of the entire biofilm.

  9. Centrifugal microfluidic platform for ultrasensitive detection of botulinum toxin.

    Science.gov (United States)

    Koh, Chung-Yan; Schaff, Ulrich Y; Piccini, Matthew E; Stanker, Larry H; Cheng, Luisa W; Ravichandran, Easwaran; Singh, Bal-Ram; Sommer, Greg J; Singh, Anup K

    2015-01-20

    We present an innovative centrifugal microfluidic immunoassay platform (SpinDx) to address the urgent biodefense and public health need for ultrasensitive point-of-care/incident detection of botulinum toxin. The simple, sample-to-answer centrifugal microfluidic immunoassay approach is based on binding of toxins to antibody-laden capture particles followed by sedimentation of the particles through a density-media in a microfluidic disk and quantification by laser-induced fluorescence. A blind, head-to-head comparison study of SpinDx versus the gold-standard mouse bioassay demonstrates 100-fold improvement in sensitivity (limit of detection = 0.09 pg/mL), while achieving total sample-to-answer time of capture beads and detection antibodies) are disconnected from the disk architecture and the reader, facilitating rapid development of new assays. SpinDx can also serve as a general-purpose immunoassay platform applicable to diagnosis of other conditions and diseases.

  10. Analysis of cantilever NEMS in centrifugal-fluidic systems

    Science.gov (United States)

    Mohsen-Nia, Mohsen; Abadian, Fateme; Abadian, Naeime; Dehkordi, Keivan Mosaiebi; Keivani, Maryam; Abadyan, Mohamadreza

    2016-07-01

    Electromechanical nanocantilevers are promising for using as sensors/detectors in centrifugal-fluidic systems. For this application, the presence of angular speed and electrolyte environment should be considered in the theoretical analysis. Herein, the pull-in instability of the nanocantilever incorporating the effects of angular velocity and liquid media is investigated using a size-dependent continuum theory. Using d’Alembert principle, the angular speed is transformed into an equivalent centrifugal force. The electrochemical and dispersion forces are incorporated considering the corrections due to the presence of electrolyte media. Two different approaches, i.e., the Rayleigh-Ritz method (RRM) and proposing a lumped parameter model (LPM), were applied to analyze the system. The models are validated with the results presented in literature. Impacts of the angular velocity, electrolyte media, dispersion forces, and size effect on the instability characteristics of the nanocantilever are discussed.

  11. Stage-efficiency of centrifugal extractor used in nuclear industry

    Institute of Scientific and Technical Information of China (English)

    吴秋林; 景山; 王兴海; 宋崇立

    2003-01-01

    The stage-efficiency of a single-stage prototype (d70) centrifugal extractor and the cascade is tested by HNO3-Nd3+ and 30%TRPO-kerosene system. The experimental results of the single-stage centrifugal extractor show that the carryover of the two phases decreases with increasing ratio of the two flow rate and rotation rate and the stage efficiency increases with not only decreasing total flow rate but also increasing rotor speed. However, the experimental results of the cascade show that the average stage efficiency of the cascade increases with not only decreasing total flow rate but also increasing rotor speed in both three-stage mode and two-stage mode.

  12. Dynamical System Analysis of Unsteady Phenomena in Centrifugal Compressor

    Institute of Scientific and Technical Information of China (English)

    YasuyukiKomatsubara; ShimpeiMizuki

    1997-01-01

    Surge and rotating stall occurring in a centrifugal compressor system are investigated by using a phase portrait reconstruction method.From experimentally measured time series of data,the method clarified the cyclic behavior of surge.For rotating stall,there still remain problems in the phase portrait due to the chaotic behavior.However,the results obtained by the present method are able to provide new insights to the modelings for surge and rotating stall.Surge and roatting stall occurring in a centrifugal compressor system are investigated by using a phase portrait reconstruction method.From experimentally measured time series of data,the method clarified the cylcic behavior of surge.For rotating stall,there still remain problems in the phase portrait due to the chaotic behavior.However,the results obtained by the present method are able to provide new insights to the modelings for surge and rotating stall.

  13. The simulation and performance of a centrifugal chiller

    Science.gov (United States)

    Jackson, W. L.; Chen, F. C.; Hwang, B. C.

    A computer simulation model was developed to analyze the performance of a water-cooled centrifugal chiller. The model is based on a heat pump thermodynamic cycle and empirical correlations for the performance of the system components. The system simulated is composed of a variable-speed centrifugal compressor with a hot-gas bypass option for capacity control, two shell-and-tube heat exchangers, and an expansion device. The model was validated and calibrated against the experimental test results of a 125-ton chiller. The performance of a similar chiller system at various operating conditions and design modifications was analyzed. System performance comparisons were made between a baseline case, cases with high-performance heat exchanger tubes and compressor motor, and various variable-speed compressor operating strategies. It was found that significant performance improvement can be realized by using variable-speed drive and on-demand control strategy.

  14. Centrifuge modeling of PGD response of buried pipe

    Institute of Scientific and Technical Information of China (English)

    Michael O'Rourke; Vikram Gadicherla; Tarek Abdoun

    2005-01-01

    A new centrifuge based method for determining the response of continuous buried pipe to PGD is presented.The physical characteristics of the RPI's 100 g-ton geotechnical centrifuge and the current lifeline experiment split-box are described: The split-box contains the model pipeline and surrounding soil and is manufactured such that half can be offset, in flight, simulating PGD. In addition, governing similitude relations which allow one to determine the physical characteristics,(diameter, wall thickness and material modulus of elasticity) of the model pipeline are presented. Finally, recorded strains induced in two buried pipes with prototype diameters of 0.63 m and 0.95 m (24 and 36 inch) subject to 0.6 and 2.0 meters (2and 6 feet) of full scale fault offsets and presented and compared to corresponding FE results.

  15. Hemocompatibility of a hydrodynamic levitation centrifugal blood pump.

    Science.gov (United States)

    Yamane, Takashi; Maruyama, Osamu; Nishida, Masahiro; Kosaka, Ryo; Sugiyama, Daisuke; Miyamoto, Yusuke; Kawamura, Hiroshi; Kato, Takahisa; Sano, Takeshi; Okubo, Takeshi; Sankai, Yoshiyuki; Shigeta, Osamu; Tsutsui, Tatsuo

    2007-01-01

    A noncontact type centrifugal pump without any complicated control or sensing modules has been developed as a long-term implantable artificial heart. Centrifugal pumps with impellers levitated by original hydrodynamic bearings were designed and have been modified through numerical analyses and in vitro tests. The hemolysis level was reduced by changing the pressure distribution around the impeller and subsequently expanding the bearing gap. Thrombus formation in the bearing was examined with in vitro thrombogenesis tests and was reduced by changing the groove shapes to increase the bearing-gap flow to 3% of the external flow. Unnecessary vortices around the vanes were also eliminated by changing the number of vanes from four to six.

  16. Considerations in designing a centrifugal atomiser for metal powder production

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Y.Y. [Department of Engineering, The University of Liverpool, Liverpool L69 3GH (United Kingdom)]. E-mail: y.y.zhao@livepool.ac.uk

    2006-07-01

    In centrifugal atomisation for metal powder production, the key to the control of the particle sizes is the design of the atomiser. This paper studies the main issues concerned in designing a centrifugal atomiser and provides guidance on the selection of an electric motor, radius of atomiser, slope angle of atomiser wall and flow rate of cooling water. In the selection of the atomiser radius, the power and material constraints as well as the hydraulic jump radius need to be considered. A cup atomiser with a slope angle of 60-70{sup o} would result in small spray droplets and thus a fine powder. The water cooling system needs to be assessed by examining the heat flow in the solid metal layer and in the atomiser.

  17. Production of centrifugal fields greater than 100 million times gravity.

    Science.gov (United States)

    Katano, R; Shimizu, S

    1979-07-01

    A high-speed rotation instrument to produce centrifugal fields greater than 100 million times gravity has been constructed. Small, solid, spherical high-carbon chromium steel rotors are suspended magnetically in high vacuum and spun by a rotating magnetic field. It is found that the spinning rotor explodes when the calculated average value of stress in the meridian plane reaches about 1.2 times the tensile strength of the material. The maximum speed of rotation so far achieved for more than a few days without bursting was obtained with a rotor of 1.50 mm diameter. The speed of 2.11 x 10(5) rev/s corresponded to a centrifugal field of 1.34 x 10(8) times gravity. Our instrument will find application in the study of nuclear atomic phenomena.

  18. Operation of Droplet-Microfluidic Devices with a Lab Centrifuge

    Directory of Open Access Journals (Sweden)

    Noorsher Ahmed

    2016-09-01

    Full Text Available Microfluidic devices are valuable for a variety of biotechnology applications, such as synthesizing biochemical libraries, screening enzymes, and analyzing single cells. However, normally, the devices are controlled using specialized pumps, which require expert knowledge to operate. Here, we demonstrate operation of poly(dimethylsiloxane devices without pumps. We build a scaffold that holds the device and reagents to be infused in a format that can be inserted into a 50 mL falcon tube and spun in a common lab centrifuge. By controlling the device design and centrifuge spin speed, we infuse the reagents at controlled flow rates. We demonstrate the encapsulation and culture of clonal colonies of red and green Escherichia coli in droplets seeded from single cells.

  19. Centrifuge Modeling of Piles Subjected to Lateral Loads

    Science.gov (United States)

    Brant, Logan; Ling, Hoe I.

    There are many applications where piles are employed to absorb and deflect lateral impact loads. Structural elements of this type are used to protect infrastructure and are commonly found at marine sites. A series of model tests have been conducted using Columbia University's centrifuge facility to better understand the performance of piles subjected to these loading conditions. A device was designed to install and laterally load single model piles during centrifuge flight. This device uniquely contains two lateral loading systems, one which allows static testing and another appropriate for dynamic tests. This research examines the behavior of tubular steel piles embedded within dry or saturated soil and subjected to varied rates of lateral loading. This investigation provides insight on the contribution of lateral loading rates to the behavior of piles.

  20. Massively parallel single-molecule manipulation using centrifugal force

    CERN Document Server

    Halvorsen, Ken

    2009-01-01

    Precise manipulation of single molecules has already led to remarkable insights in physics, chemistry, biology and medicine. However, widespread adoption of single-molecule techniques has been impeded by equipment cost and the laborious nature of making measurements one molecule at a time. We have solved these issues with a new approach: massively parallel single-molecule force measurements using centrifugal force. This approach is realized in a novel instrument that we call the Centrifuge Force Microscope (CFM), in which objects in an orbiting sample are subjected to a calibration-free, macroscopically uniform force-field while their micro-to-nanoscopic motions are observed. We demonstrate high-throughput single-molecule force spectroscopy with this technique by performing thousands of rupture experiments in parallel, characterizing force-dependent unbinding kinetics of an antibody-antigen pair in minutes rather than days. Additionally, we verify the force accuracy of the instrument by measuring the well-est...

  1. Scalp psoriasis associated with central centrifugal cicatricial alopecia

    Directory of Open Access Journals (Sweden)

    Krista N. Larson

    2017-01-01

    Full Text Available Scalp psoriasis is a very common dermatological condition with a variety of presentations, but only rarely presents as severe alopecia. We present a case of a 50-year-old female with many years of recalcitrant hair loss that was thought to be secondary to central centrifugal cicatricial alopecia which was later diagnosed as psoriasis. This case highlights an interesting presentation and rare complication of a common disease.

  2. A Review of Centrifugal Testing of Gasoline Contamination and Remediation

    OpenAIRE

    Jay N. Meegoda; Liming Hu

    2011-01-01

    Leaking underground storage tanks (USTs) containing gasoline represent a significant public health hazard. Virtually undetectable to the UST owner, gasoline leaks can contaminate groundwater supplies. In order to develop remediation plans one must know the extent of gasoline contamination. Centrifugal simulations showed that in silty and sandy soils gasoline moved due to the physical process of advection and was retained as a pool of free products above the water table. However, in clayey soi...

  3. Computational and Experimental Study of an Industrial Centrifugal Compressor Volute

    Institute of Scientific and Technical Information of China (English)

    HarriPitkanen; HannuEsa; 等

    2000-01-01

    A centrifugal compressor with a vaneless diffuser was studied experimentally and numericallly.The main target of the study was to analyze the volute flow.Two different volute geometries was studied.The numerical solution was done by using a steady-state RANS code at both design and off-design conditions.Both calculated and measured pressure and velocity distributions are presented.

  4. Centrifugal Blower for Personal Air Ventilation System (PAVS) - Phase 1

    Science.gov (United States)

    2015-02-01

    functionality. 15. SUBJECT TERMS COOLING SBIR REPORTS AXIAL FLOW FANS OFF THE SHELF EQUIPMENT BLOWERS LIGHTWEIGHT CENTRIFUGAL FORCE...HEAT STRESS (PHYSIOLOGY) AIR FLOW VENTILATION PORTABLE EQUIPMENT PERSONAL COOLING SYSTEMS EFFICIENCY EVAPORATION INTEGRATED SYSTEMS PROTOTYPES...gH Vn ad s ad s 4 1 4 3     is angular speed (2rpm) V is volumetric flow rate Had is the fan pumping head (in meters) g is the

  5. Centrifuge modeling of rocking-isolated inelastic RC bridge piers

    OpenAIRE

    Loli, Marianna; Knappett, Jonathan A; Brown, Michael J.; Anastasopoulos, Ioannis; GAZETAS, George

    2014-01-01

    Experimental proof is provided of an unconventional seismic design concept, which is based on deliberately underdesigning shallow foundations to promote intense rocking oscillations and thereby to dramatically improve the seismic resilience of structures. Termed rocking isolation, this new seismic design philosophy is investigated through a series of dynamic centrifuge experiments on properly scaled models of a modern reinforced concrete (RC) bridge pier. The experimental method reproduces th...

  6. Centrifugal stretching of 170Hf in the interacting boson model

    Directory of Open Access Journals (Sweden)

    Werner V.

    2014-03-01

    Full Text Available We present the results of a recent experiment to deduce lifetimes of members of the ground state rotational band of 170Hf, which show the effect of centrifugal stretching in this deformed isotope. Results are compared to the geometrical confined beta-soft(CBS rotor model, as well as to the interacting boson model (IBM. Two methods to correct for effects due to the finite valence space within the IBM are proposed.

  7. Comparative hemolysis study of clinically available centrifugal pumps.

    Science.gov (United States)

    Naito, K; Suenaga, E; Cao, Z L; Suda, H; Ueno, T; Natsuaki, M; Itoh, T

    1996-06-01

    Centrifugal pumps have become important devices for cardiopulmonary bypass and circulatory assistance. Five types of centrifugal pumps are clinically available in Japan. To evaluate the blood trauma caused by centrifugal pumps, a comparative hemolysis study was performed under identical conditions. In vitro hemolysis test circuits were constructed to operate the BioMedicus BP-80 (Medtronic, BioMedicus), Sarns Delphin (Sarns/3M Healthcare), Isoflow (St. Jude Medical [SJM]), HPM-15 (Nikkiso), and Capiox CX-SP45 (Terumo). The hemolysis test loop consisted of two 1.5 m lengths of polyvinyl chloride tubing with a 3/8-inch internal diameter, a reservoir with a sampling port, and a pump head. All pumps were set to flow at 6 L/min against the total pressure head of 120 mm Hg. Experiments were conducted simultaneously for 6 h at room temperature (21 degrees C) with fresh bovine blood. Blood samples for plasma-free hemoglobin testing were taken, and the change in temperature at the pump outlet port was measured during the experiment. The mean pump rotational speeds were 1,570, 1,374, 1,438, 1,944, and 1,296 rpm, and the normalized indexes of hemolysis were 0.00070, 0.00745, 0.00096, 0.00066, 0.00090 g/100 L for the BP-80, Sarns, SJM, Nikkiso, and Terumo pumps, respectively. The change in temperature at the pump outlet port was the least for the Nikkiso pump (1.8 degrees C) and the most with the SJM pump (3.8 degrees C). This study showed that there is no relationship between the pump rotational speed (rpm) and the normalized index of hemolysis in 5 types of centrifugal pumps. The pump design and number of impellers could be more notable factors in blood damage.

  8. Prenatal centrifugation: A model for fetal programming of adult weight?

    Science.gov (United States)

    Baer, Lisa A.; Rushing, Linda; Wade, Charles E.; Ronca, April E.

    2005-08-01

    'Fetal programming' is a newly emerging field that is revealing astounding insights into the prenatal origins of adult disease, including metabolic, endocrine, and cardiovascular pathophysiology. In the present study, we tested the hypothesis that rat pups conceived, gestated and born at 2-g have significantly reduced birth weights and increased adult body weights as compared to 1-g controls. Offspring were produced by mating young adult male and female rats that were adapted to 2-g centrifugation. Female rats underwent conception, pregnancy and birth at 2-g. Newborn pups in the 2-g condition were removed from the centrifuge and fostered to non-manipulated, newly parturient dams maintained at 1-g. Comparisons were made with 1-g stationary controls, also cross- fostered at birth. As compared to 1-g controls, birth weights of pups gestated and born at 2-g were significantly reduced. Pup body weights were significantly reduced until Postnatal day (P)12. Beginning on P63, body weights of 2-g-gestated offspring exceeded those of 1-g controls by 7-10%. Thus, prenatal rearing at 2-g restricts neonatal growth and increases adult body weight. Collectively, these data support the hypothesis that 2-g centrifugation alters the intrauterine milieu, thereby inducing persistent changes in adult phenotype.

  9. Governing Principles of Alginate Microparticle Synthesis with Centrifugal Forces.

    Science.gov (United States)

    Eral, Huseyin Burak; Safai, Eric R; Keshavarz, Bavand; Kim, Jae Jung; Lee, Jisoek; Doyle, P S

    2016-07-19

    A controlled synthesis of polymeric particles is becoming increasingly important because of emerging applications ranging from medical diagnostics to self-assembly. Centrifugal synthesis of hydrogel microparticles is a promising method, combining rapid particle synthesis and the ease of manufacturing with readily available laboratory equipment. This method utilizes centrifugal forces to extrude an aqueous polymer solution, sodium alginate (NaALG) through a nozzle. The extruded solution forms droplets that quickly cross-link upon contact with aqueous calcium chloride (CaCl2) solution to form hydrogel particles. The size distribution of hydrogel particles is dictated by the pinch-off behavior of the extruded solution through a balance of inertial, viscous, and surface tension stresses. We identify the parameters dictating the particle size and provide a numerical correlation predicting the average particle size. Furthermore, we create a phase map identifying different pinch-off regimes (dripping without satellites, dripping with satellites, and jetting), explaining the corresponding particle size distributions, and present scaling arguments predicting the transition between regimes. By shedding light on the underlying physics, this study enables the rational design and operation of particle synthesis by centrifugal forces.

  10. Numerical Analysis and Centrifuge Modeling of Shallow Foundations

    Institute of Scientific and Technical Information of China (English)

    罗强; 栾茂田; 杨蕴明; 王忠涛; 赵守正

    2014-01-01

    The influence of non-coaxial constitutive model on predictions of dense sand behavior is investigated in this paper. The non-coaxial model with strain softening plasticity is applied into finite-element program ABAQUS, which is first used to predict the stress-strain behavior and the non-coaxial characteristic between the orientations of the principal stress and principal plastic strain rate in simple shear tests. The model is also used to predict load settlement responses and bearing capacity factors of shallow foundations. A series of centrifuge tests for shallow foundations on saturated dense sand are performed under drained conditions and the test results are compared with the corresponding numerical results. Various footing dimensions, depths of embedment, and footing shapes are considered in these tests. In view of the load settlement relationships, the stiffness of the load-displacement curves is significantly affected by the non-coaxial model compared with those predicted by the coaxial model, and a lower value of non-coaxial modulus gives a softer response. Considering the soil behavior at failure, the coaxial model predictions of bearing capacity factors are more advanced than those of centrifuge test results and the non-coaxial model results;besides, the non-coaxial model gives better predictions. The non-coaxial model predictions are closer to those of the centrifuge results when a proper non-coaxial plastic modulus is chosen.

  11. Subchronic centrifugal mechanical assist in an unheparinized calf model.

    Science.gov (United States)

    Wagner-Mann, C; Curtis, J; Mann, F A; Turk, J; Demmy, T; Turpin, T

    1996-06-01

    The purpose of this study was to determine whether the major centrifugal pumps currently in use in the United States (Medtronic, BioMedicus BioPump and Carmeda-coated BioPump, Sarns 3M centrifugal pump, and St. Jude Medical Lifestream) could function as left mechanical assist devices in the subchronic (72 h) unheparinized calf model. Calves were instrumented for left atrial to aorta ex vivo assist, and the pump flow was set at 3.5 +/- 0.4 L/min. Two calves (Sarns 3M and St. Jude) survived 72 h of pumping without clinical complications. The other 2 calves died at 62 and 66 h (Medtronic BioPump and Carmeda-coated BioPump, respectively); both had pelvic limb paralysis. The seal of the Sarns 3M pump head ruptured after approximately 36 h of pumping and required replacement. On postmortem examination, pump-associated thromboembolic lesions were detected in 3 of the 4 calves in one or more of the following organs: kidneys, pancreas, abomasum, duodenum, ileum, spleen, and lumbar spinal cord. The calf with the Sarns 3M pump had no discernable lesions. Because of the clinical abnormalities and postmortem lesions in the unheparinized calf model, it was suggested that anticoagulation is necessary for conducting centrifugal mechanical assist studies in calves using presently available technology.

  12. Modelling of horizontal centrifugal casting of work roll

    Science.gov (United States)

    Xu, Zhian; Song, Nannan; Tol, Rob Val; Luan, Yikun; Li, Dianzhong

    2012-07-01

    A numerical model to simulate horizontal centrifugal roll castings is presented in this paper. In order to simulate the flow fluid and solidification of horizontal centrifugal roll casting correctly, the model uses a body fitted mesh technique to represent the geometry. This new method maps a plate layer mesh to a circular mesh. The smooth body fitted mesh method gives more accurate calculation results for cylindrical geometries. A velocity depending on the angular velocity and inner radius of the mould is set up as a velocity boundary condition. The fluid flow coupled with heat transfer and solidification in a rapidly rotating roll is simulated. A gravity free falling method is applied as a pouring condition. A moveable pouring system is also used in the simulations. High speed steel is used to produce the work roll. Two different gating positions and a moveable gating system are simulated in this paper. Results show that the position of pouring system has a significant influence on the temperature distribution. The temperature distribution at a fixed central pouring system is more favourable than the distribution from a side pouring system. A moving gating system method is a better way to obtain a uniform temperature field in centrifugal casting and offers an alternative for existing techniques.

  13. Effect of centrifugal forces on dimensional error of bored shapes

    Science.gov (United States)

    Arsuaga, M.; de Lacalle, L. N. López; Lobato, R.; Urbikain, G.; Campa, F.

    2012-04-01

    Boring operations of deep holes with a slender boring bar are often hindered by the precision because of their low static stiffness and high deformations. Because of that, it is not possible to remove much larger depths of cuts than the nose radius of the tool, unlike the case of turning and face milling operations, and consequently, the relationship between the cutting force distribution, tool geometry, feed rate and depth of cut becomes non-linear and complex. This problem gets worse when working with a rotating boring head where apart from the cutting forces and the variation of the inclination angle because of shape boring, the bar and head are affected by de centrifugal forces. The centrifugal forces, and therefore the centrifugal deflection, will vary as a function of the rotating speed, boring bar mass distribution and variable radial position of the bar in shape boring. Taking in to account all this effects, a load and deformation model was created. This model has been experimentally validated to use as a corrector factor of the radial position of the U axis in the boring head.

  14. Microstructures of Al-Al3Ti functionally graded materials fabricated by centrifugal solid-particle method and centrifugal in situ method

    Science.gov (United States)

    Watanabe, Yoshimi; Zhou, Qi; Sato, Hisashi; Fujii, Toshiyuki; Inamura, Tomonari

    2017-01-01

    Methods of fabrication by centrifugal casting for functionally graded materials (FGMs) can be classified into two categories on the basis of the relationship between the process temperature and the liquidus temperature of a master alloy. They are the centrifugal solid-particle method and centrifugal in situ method, which could be carried out at process temperatures lower and higher than the liquidus temperature of the master alloy, respectively. In a previous study, it was found that the microstructures of Al-Al3Ti FGMs fabricated by the centrifugal in situ method processed at 1600 °C were different from those fabricated by the centrifugal solid-particle method processed at 800 °C. Although it is expected that the FGMs fabricated by the centrifugal in situ method processed at approximately the liquidus temperature should show extraordinary microstructures, those microstructures have not been observed. In this study, the microstructures of Al-Al3Ti FGMs fabricated at 1000 °C (centrifugal solid-particle method) and 1200 °C (centrifugal in situ method) were investigated.

  15. Water Drainage from Unsaturated Soils in a Centrifuge Permeameter

    Science.gov (United States)

    Ornelas, G.; McCartney, J.; Zhang, M.

    2013-12-01

    This study involves an analysis of water drainage from an initially saturated silt layer in a centrifuge permeameter to evaluate the hydraulic properties of the soil layer in unsaturated conditions up to the point where the water phase becomes discontinuous. These properties include the soil water retention curve (SWRC) and the hydraulic conductivity function (HCF). The hydraulic properties of unsaturated silt are used in soil-atmosphere interaction models that take into account the role of infiltration and evaporation of water from soils due to atmospheric interaction. These models are often applied in slope stability analyses, landfill cover design, aquifer recharge analyses, and agricultural engineering. The hydraulic properties are also relevant to recent research concerning geothermal heating and cooling, as they can be used to assess the insulating effects of soil around underground heat exchangers. This study employs a high-speed geotechnical centrifuge to increase the self-weight of a compacted silt specimen atop a filter plate. Under a centrifuge acceleration of N times earth's gravity, the concept of geometric similitude indicates that the water flow process in a small-scale soil layer will be similar to those in a soil layer in the field that is N times thicker. The centrifuge acceleration also results in an increase in the hydraulic gradient across the silt specimen, which causes water to flow out of the pores following Darcy's law. The drainage test was performed until the rate of liquid water flow out of the soil layer slowed to a negligible level, which corresponds to the transition point at which further water flow can only occur due to water vapor diffusion following Fick's law. The data from the drainage test in the centrifuge were used to determine the SWRC and HCF at different depths in the silt specimen, which compared well with similar properties defined using other laboratory tests. The transition point at which liquid water flow stopped (and

  16. Cyclonic Separation Technology: Researches and Developments

    Institute of Scientific and Technical Information of China (English)

    汪华林; 张艳红; 王剑刚; 刘洪来

    2012-01-01

    Centered on thetechniques and industrial applications of the reinforced cyclonic separation process, its principles and mechanism for separation ot ions, molecules and their aggregates using polyalsperse aroplets are discussed generally; the characteristics and influential factors of fish-hook phenomenon of the grade efficiency curve in cyclonic separation for both gas and liquid are analyzed; and the influence of shear force on particle be- havior (or that of particle swarm) is also summarized. A novel idea for cyclonic separation is presented here: enhancing the cyclonic seoaration process of ions, molecules and their aggregates with monodisperse microspheres and their surface grafting, rearranging the distribution of particles by size using centrifugal field, reinforcing the cyclonic separation performance with orderly arranged particle swarm. Also the investigation of the shortcut flow, recirculation flow, the asymmetric structure and non-linear characteristics of the cyclonic flow field with a com-bined method of Volumetric 3-component Velocimetry (V3V) and Phase-Doppler Particle Anemometer (PDPA) are elaborated. It is recommended to develop new systems for the separation of heterogeneous phases with cyclonic technology, in accordance with the capture and reuse of CO2, methanol to olefins (MTO) process, coal transfer, andthe exploitation of oil shale.

  17. System of Thermal Balance Maintenance in Modern Test Benches for Centrifugal Pumps

    Directory of Open Access Journals (Sweden)

    A. I. Petrov

    2015-01-01

    Full Text Available The article “Systems of the heat balance maintenance in modern test benches for centrifugal pumps” makes the case to include cooling systems of a working fluid (heat setting in test bench for impeller pumps. It briefly summarizes an experience of bench building to test centrifugal pumps, developed at the BMSTU Department E-10 over the last 10 years. The article gives the formulas and the algorithm to calculate the heat capacity of different types of impeller pumps when tested at the bench as ell as to determine the heating time of the liquid in the bench without external cooling. Based on analysis of the power balance of a centrifugal pump, it is shown that about 90% of the pump unit-consumed electric power in terminals is used for heating up the working fluid in the loop of the test bench. The article gives examples of elementary heat calculation of the pump operation within the test bench. It presents the main types of systems to maintain thermal balance, their advantages, disadvantages and possible applications. The cooling system schemes for open and closed version of the benches both with built-in and with an independent cooling circuit are analysed. The paper separately considers options of such systems for large benches using the cooling tower as a cooling device in the loop, and to test the pumps using the hydraulic fluids other than water, including those at high temperatures of working fluids; in the latter case a diagram of dual-circuit cooling system "liquid-liquid-air" is shown. The paper depicts a necessity to use ethylene glycol coolant in the two-loop cooling bench. It provides an example of combining the functions of cooling and filtration in a single cooling circuit. Criteria for effectiveness of these systems are stated. Possible ways for developing systems to maintain a thermal balance, modern methods of regulation and control are described. In particular, the paper shows the efficiency of frequency control of the

  18. A high-efficiency superhydrophobic plasma separator.

    Science.gov (United States)

    Liu, Changchun; Liao, Shih-Chuan; Song, Jinzhao; Mauk, Michael G; Li, Xuanwen; Wu, Gaoxiang; Ge, Dengteng; Greenberg, Robert M; Yang, Shu; Bau, Haim H

    2016-02-01

    To meet stringent limit-of-detection specifications for low abundance target molecules, a relatively large volume of plasma is needed for many blood-based clinical diagnostics. Conventional centrifugation methods for plasma separation are not suitable for on-site testing or bedside diagnostics. Here, we report a simple, yet high-efficiency, clamshell-style, superhydrophobic plasma separator that is capable of separating a relatively large volume of plasma from several hundred microliters of whole blood (finger-prick blood volume). The plasma separator consists of a superhydrophobic top cover with a separation membrane and a superhydrophobic bottom substrate. Unlike previously reported membrane-based plasma separators, the separation membrane in our device is positioned at the top of the sandwiched whole blood film to increase the membrane separation capacity and plasma yield. In addition, the device's superhydrophobic characteristics (i) facilitates the formation of well-defined, contracted, thin blood film with a high contact angle; (ii) minimizes biomolecular adhesion to surfaces; (iii) increases blood clotting time; and (iv) reduces blood cell hemolysis. The device demonstrated a "blood in-plasma out" capability, consistently extracting 65 ± 21.5 μL of plasma from 200 μL of whole blood in less than 10 min without electrical power. The device was used to separate plasma from Schistosoma mansoni genomic DNA-spiked whole blood with a recovery efficiency of >84.5 ± 25.8%. The S. mansoni genomic DNA in the separated plasma was successfully tested on our custom-made microfluidic chip by using loop mediated isothermal amplification (LAMP) method.

  19. Laser Anemometer Measurements of the Flow Field in a 4:1 Pressure Ratio Centrifugal Impeller

    Science.gov (United States)

    Skoch, G. J.; Prahst, P. S.; Wernet, M. P.; Wood, J. R.; Strazisar, A. J.

    1997-01-01

    A laser-doppler anemometer was used to obtain flow-field velocity measurements in a 4:1 pressure ratio, 4.54 kg/s (10 lbm/s), centrifugal impeller, with splitter blades and backsweep, which was configured with a vaneless diffuser. Measured through-flow velocities are reported for ten quasi-orthogonal survey planes at locations ranging from 1% to 99% of main blade chord. Measured through-flow velocities are compared to those predicted by a 3-D viscous steady flow analysis (Dawes) code. The measurements show the development and progression through the impeller and vaneless diffuser of a through-flow velocity deficit which results from the tip clearance flow and accumulation of low momentum fluid centrifuged from the blade and hub surfaces. Flow traces from the CFD analysis show the origin of this deficit which begins to grow in the inlet region of the impeller where it is first detected near the suction surface side of the passage. It then moves toward the pressure side of the channel, due to the movement of tip clearance flow across the impeller passage, where it is cut by the splitter blade leading edge. As blade loading increases toward the rear of the channel the deficit region is driven back toward the suction surface by the cross-passage pressure gradient. There is no evidence of a large wake region that might result from flow separation and the impeller efficiency is relatively high. The flow field in this impeller is quite similar to that documented previously by NASA Lewis in a large low-speed backswept impeller.

  20. Task 9 - centrifugal membrane filtration. Semi-annual report April 1--September 30, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Stepan, D.J.; Moe, T.A.; Collings, M.E.

    1997-05-01

    This report assesses a centrifugal membrane filtration technology developed by SpinTek Membrane Systems, Inc. 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. The Tank Waste Focus Area was chosen for study. Membrane-screening tests were performed with the STC-X4 static test cell filtration unit, using five ceramic membranes with different pore size and composition. Based on permeate flux, a 0.25-{mu}m TiO{sub 2}/Al{sub 2}O{sub 3} membrane was selected for detailed performance evaluation using the centrifugal membrane filtration unit with a surrogate tank waste solution. The performance of the unit was evaluated with a statistical test design that determined the effect of temperature, pressure, membrane rotational speed, and solids loading on permeate flux. All four variables were found to be statistically significant, with the magnitude of the effect in the order of temperature, solids loading, rotor speed, and pressure. Temperature, rotor speed, and pressure had an increasing effect on flux with increasing value, while increases in solids loading showed a decrease in permeate flux. Significant interactions between rotor speed and solids loading and pressure and solids loading were also observed. The regression equation derived from test data had a correlation coefficient of 0.934, which represents a useful predictive capability for integrating the technology into DOE cleanup efforts. An extended test run performed on surrogate waste 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.

  1. Industrial case study on alkaloids purification by pH-zone refining centrifugal partition chromatography.

    Science.gov (United States)

    Kotland, Alexis; Chollet, Sébastien; Diard, Catherine; Autret, Jean-Marie; Meucci, Jeremy; Renault, Jean-Hugues; Marchal, Luc

    2016-11-25

    The industrial potential of pH-zone refining centrifugal partition chromatography has been evaluated by studying the purification of pharmaceutical ingredients at the pilot scale. For the first time, a scale up methodology based on both column capacity and mass transfer efficiency as invariants was developed. The purification of catharanthine and vindoline from an industrial crude extract of aerial parts of Catharanthus roseus, was used as a case of study. Toluene/CH3CN/water (4/1/5, v/v/v) was selected as biphasic solvent system, triethylamine as retainer in the organic stationary phase and sulphuric acid as displacer in the aqueous mobile phase. The separation intensification was performed on a 36mL CPC column equipped with 832 partition twin-cells. The combined effects of four parameters (displacer and retainer concentrations for intensive parameters, flow rate and rotational speed for extensive parameters) were studied by design of experiment in order to maximize both recoveries and productivities. Then, scale change was done on two larger columns (305mL and 1950mL of capacity) equipped with only 231 and 238 partition cells. For this step, it has been shown that the global mass transfer coefficient k0a (the efficiency of a column design) and the stationary phase retention (the capacity of the column) were relevant and useful scale up invariants. A CPC model based on acid-base equilibriums and interfacial mass transfer in continuously stirred tank reactors in series was used to predict fully separations on larger CPC column at the optimized operating conditions and to guide the CPC user in its scale-up strategy. The experimental validation on pilot CPC column, by injecting up to 150g of Catharanthus roseus crude extract on the 1950mL column highlighted the preservation of the separation quality, the non-linear character of the scale up in centrifugal partition chromatography and that a productivity of about 4kg of processed crude extract per day can be reached

  2. Enriched surface acidity for surfactant-free suspensions of carboxylated carbon nanotubes purified by centrifugation

    Directory of Open Access Journals (Sweden)

    Elizabeth I. Braun

    2016-06-01

    Full Text Available It is well known that surfactant-suspended carbon nanotube (CNT samples can be purified by centrifugation to decrease agglomerates and increase individually-dispersed CNTs. However, centrifugation is not always part of protocols to prepare CNT samples used in biomedical applications. Herein, using carboxylated multi-walled CNTs (cMWCNTs suspended in water without a surfactant, we developed a Boehm titrimetric method for the analysis of centrifuged cMWCNT suspensions and used it to show that the surface acidity of oxidized carbon materials in aqueous cMWCNT suspensions was enriched by ∼40% by a single low-speed centrifugation step. This significant difference in surface acidity between un-centrifuged and centrifuged cMWCNT suspensions has not been previously appreciated and is important because the degree of surface acidity is known to affect the interactions of cMWCNTs with biological systems.

  3. Bioreactor-free tissue engineering: directed tissue assembly by centrifugal casting.

    Science.gov (United States)

    Mironov, Vladimir; Kasyanov, Vladimir; Markwald, Roger R; Prestwich, Glenn D

    2008-02-01

    Casting is a process by which a material is introduced into a mold while it is liquid, allowed to solidify in a predefined shape inside the mold, and then removed to give a fabricated object, part or casing. Centrifugal casting could be defined as a process of molding using centrifugal forces. Although the centrifugal casting technology has a long history in metal manufacturing and in the plastics industry, only recently has this technology attracted the attention of tissue engineers. Initially, centrifugation was used to optimize cell seeding on a solid scaffold. More recently, centrifugal casting has been used to create tubular scaffolds and both tubular and flat multilayered, living tissue constructs. These newer applications were enabled by a new class of biocompatible in situ crosslinkable hydrogels that mimic the extracellular matrix. Herein the authors summarize the state of the art of centrifugal casting technology in tissue engineering, they outline associated technological challenges, and they discuss the potential future for clinical applications.

  4. Mathematical model of the component mixture distribution in the molten cast iron during centrifugation (sedimentation)

    Science.gov (United States)

    Bikulov, R. A.; Kotlyar, L. M.

    2014-12-01

    For the development and management of the manufacturing processes of axisymmetric articles with compositional structure by centrifugal casting method [1,2,3,4] is necessary to create a generalized mathematical model of the dynamics of component mixture in the molten cast iron during centrifugation. In article. based on the analysis of the dynamics of two-component mixture at sedimentation, a method of successive approximations to determine the distribution of a multicomponent mixture by centrifugation in a parabolic crucible is developed.

  5. Methods of observation of the centrifugal quantum states of neutrons

    Science.gov (United States)

    Cubitt, R.; Nesvizhevsky, V. V.; Petukhov, A. K.; Voronin, A. Yu.; Pignol, G.; Protasov, K. V.; Gurshijants, P.

    2009-12-01

    We propose methods for observation of the quasi-stationary states of neutrons, localized near a curved mirror surface. The bounding effective well is formed by the centrifugal potential and the mirror's optical potential. This phenomenon is an example of an exactly solvable "quantum bouncer" problem that can be studied experimentally. It could provide a new tool for studying fundamental neutron-matter interactions, neutron quantum optics and surface physics effects. The feasibility of observation of such quantum states has been proven in first experiments.

  6. Methods of observation of the centrifugal quantum states of neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Cubitt, R. [Institut Laue-Langevin (ILL), 6 rue Jules Horowitz, F-38042 Grenoble (France); Nesvizhevsky, V.V., E-mail: nesvizhevsky@ill.e [Institut Laue-Langevin (ILL), 6 rue Jules Horowitz, F-38042 Grenoble (France); Petukhov, A.K. [Institut Laue-Langevin (ILL), 6 rue Jules Horowitz, F-38042 Grenoble (France); Voronin, A.Yu., E-mail: dr.a.voronin@gmail.co [P.N. Lebedev Physical Institute, 53 Leninsky Prospekt, 119991 Moscow (Russian Federation); Pignol, G.; Protasov, K.V. [Laboratoire de Physique Subatomique et de Cosmologie (LPSC), IN2P3-CNRS, UJF, 53, Avenue des Martyrs, F-38026 Grenoble (France); Gurshijants, P. [Institute of Solid State Physics (ISSP), Institutskaya Street 2, 142432 Chernogolovka, Moscow Region (Russian Federation)

    2009-12-11

    We propose methods for observation of the quasi-stationary states of neutrons, localized near a curved mirror surface. The bounding effective well is formed by the centrifugal potential and the mirror's optical potential. This phenomenon is an example of an exactly solvable 'quantum bouncer' problem that can be studied experimentally. It could provide a new tool for studying fundamental neutron-matter interactions, neutron quantum optics and surface physics effects. The feasibility of observation of such quantum states has been proven in first experiments.

  7. Capture into resonance and phase space dynamics in optical centrifuge

    CERN Document Server

    Armon, Tsafrir

    2016-01-01

    The process of capture of a molecular enesemble into rotational resonance in the optical centrifuge is investigated. The adiabaticity and phase space incompressibility are used to find the resonant capture probability in terms of two dimensionless parameters P1,P2 characterising the driving strength and the nonlinearity, and related to three characteristic time scales in the problem. The analysis is based on the transformation to action-angle variables and the single resonance approximation, yielding reduction of the three-dimensional rotation problem to one degree of freedom. The analytic results for capture probability are in a good agreement with simulations. The existing experiments satisfy the validity conditions of the theory.

  8. Centrifugal experimental study of suction bucket foundations under dynamic loading

    Science.gov (United States)

    Lu, Xiaobing; Wu, Yongren; Jiao, Bintian; Wang, Shuyun

    2007-12-01

    Centrifugal experiments were carried out to investigate the responses of suction bucket foundations under horizontal and vertical dynamic loading. It is shown that when the loading amplitude is over a critical value, the sand at the upper part around the bucket is softened or even liquefied. The excess pore pressure decreases from the upper part to the lower part of the sand layer in the vertical direction and decreases radially from the bucket’s side wall in the horizontal direction. Large settlements of the bucket and the sand layer around the bucket are induced by dynamic loading. The dynamic responses of the bucket with smaller height (the same diameter) are heavier.

  9. Silver nanodisks: size selection via centrifugation and optical properties.

    Science.gov (United States)

    Germain, V; Brioude, A; Ingert, D; Pileni, M P

    2005-03-22

    Silver nanodisks, having two different sizes, and spherical particles are synthesized by soft chemistry. By using centrifugation, nanodisks are mainly selected. The experimental absorption spectra of these nanodisks with different sizes are compared to those simulated using the discrete dipole approximation method. For small nanodisk sizes, the nanodisk shape is neglected and the simulated spectra closest to the experiments are obtained by assuming a spheroidal particle. Conversely, for larger nanodisks, the precise geometries represented by snip and aspect ratio are needed for good agreement between experiments and simulations.

  10. Fast Centrifugal Partition Chromatography Fractionation of Concentrated Agave (Agave salmiana) Sap to Obtain Saponins with Apoptotic Effect on Colon Cancer Cells.

    Science.gov (United States)

    Santos-Zea, Liliana; Fajardo-Ramírez, Oscar R; Romo-López, Irasema; Gutiérrez-Uribe, Janet A

    2016-03-01

    Separation of potentially bioactive components from foods and plant extracts is one of the main challenges for their study. Centrifugal partition chromatography has been a successful technique for the screening and identification of molecules with bioactive potential, such as steroidal saponins. Agave is a source of steroidal saponins with anticancer potential, though the activity of these compounds in concentrated agave sap has not been yet explored. In this study, fast centrifugal partition chromatography (FCPC) was used coupled with in vitro tests on HT-29 cells as a screening procedure to identify apoptotic saponins from an acetonic extract of concentrated agave sap. The three most bioactive fractions obtained by FCPC at partition coefficients between 0.23 and 0.4 contained steroidal saponins, predominantly magueyoside b. Flow cytometry analysis determined that the fraction rich in kammogenin and manogenin glycosides induced apoptosis, but when gentrogenin and hecogenin glycosides were also found in the fraction, a necrotic effect was observed. In conclusion, this study provides the evidence that steroidal saponins in concentrated agave sap were potential inductors of apoptosis and that it was possible to separate them using fast centrifugal partition chromatography.

  11. Size-isolation of ultrasound-mediated phase change perfluorocarbon droplets using differential centrifugation.

    Science.gov (United States)

    Mercado, Karla P; Radhakrishnan, Kirthi; Stewart, Kyle; Snider, Lindsay; Ryan, Devin; Haworth, Kevin J

    2016-05-01

    Perfluorocarbon droplets that are capable of an ultrasound-mediated phase transition have applications in diagnostic and therapeutic ultrasound. Techniques to modify the droplet size distribution are of interest because of the size-dependent acoustic response of the droplets. Differential centrifugation has been used to isolate specific sizes of microbubbles. In this work, differential centrifugation was employed to isolate droplets with diameters between 1 and 3 μm and 2 and 5 μm from an initially polydisperse distribution. Further, an empirical model was developed for predicting the droplet size distribution following differential centrifugation and to facilitate the selection of centrifugation parameters for obtaining desired size distributions.

  12. Adiabatic field-free alignment of asymmetric top molecules with an optical centrifuge

    CERN Document Server

    Korobenko, A

    2015-01-01

    We use an optical centrifuge to align asymmetric top $\\mathrm{SO_2}$ molecules by adiabatically spinning their most polarizable O-O axis. The effective centrifugal potential in the rotating frame confines sulfur atoms to the plane of the laser-induced rotation, leading to the planar molecular alignment which persists after the molecules are released from the centrifuge. Periodic appearance of the full three-dimensional alignment, typically observed only with linear and symmetric top molecules, is also detected. Together with strong in-plane centrifugal forces, which bend the molecules by up to 10 degrees, permanent field-free alignment offers new ways of controlling molecules with laser light.

  13. High Order Centrifugal Distortion Corrections to Energy Levels of Asymmetric Top Molecules

    Institute of Scientific and Technical Information of China (English)

    LIU Yu-Yan; LIU Xiao-Yong; LIU Hong-Ping; GUO Yuan-Qing; HUANG Guang-Ming; LIN Jie-Li; GAO Hui

    2000-01-01

    High order centrifugal distortion terms have been derived and added to the effective Hamiltonian of asymmetric top molecules. Based on this Hamiltonian, a program in Fortran 77 has been developed for spectral analysis of asymmetric top molecules. The high order centrifugal distortion terms are found to be non-negligible even for the low-lying rotational transitions of molecules, such as Ha 18O, subjected to severe centrifugal distortion effect,and for the high-lying rotational transitions of molecules, such as 14N16O2 subjected to the moderate centrifugal distortion effect.

  14. Computer precision simulation for titanium casting centrifugal mold filling of prescision titanium castings

    Directory of Open Access Journals (Sweden)

    Daming XU

    2004-08-01

    Full Text Available Computer simulation codes were developed based on proposed mathematical model for centrifugal mold filling processes and previous computer software for 3D mold filling and solidification of castings. 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 unde 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 prcision castings.

  15. The Monitoring Of Running Stability For The Tripod Type Centrifuge%三足式离心机运行稳定性的监控

    Institute of Scientific and Technical Information of China (English)

    徐罕

    2014-01-01

    The tripod type centrifuge is widely used for the production department of light industry, chemical industry, medicine and metallurgy etc. It is a kind of equipment which is used to separate solid particles or crystals from solutions or mixed liquid. The running stability of this kind of centrifuge is depended on the water-penetrability of separated liquid. To a liquid with good water-penetrability, materials have entered onto a screen grate which always carries an eccentric load by reason of an uneven distribution,so that the suspended materials have created the disturbing dynamic source of centrifuge caused by centrifugal forces. When the disturbing forces have increased with the eccentric load of materials to reach at a certain degree, the suspended materials, will tumble down and the centrifuge will appear unstable in running state. This phenomenon has become a problem child of tripod type centrifuge.%三足式离心机广泛应用于轻工、化工、医疗以及冶金工业等生产部门,是从溶液中分离出晶体或固体颗粒的一种设备。该型离心机的运行稳定性,取决于被分离液体的透水性。对于透水性良好的物料,进入筛栏后往往分布不均形成偏载,由此产生的离心力构成了对离心机机体运行的扰动力源,当此力源强度随偏载量达到一定程度后,机体将产生倾翻,离心机将出现运行失稳,这种现象已成为三足式离心机运行中的一个急需解决的问题。

  16. Design and Characterization of a Centrifugal Compressor Surge Test Rig

    Directory of Open Access Journals (Sweden)

    Kin Tien Lim

    2011-01-01

    Full Text Available 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 characterization of the compressor performance. The behavior of the compressor during surge is analyzed by driving the experimental setup into surge. Two fundamental frequencies, 21 Hz and 7 Hz, connected to the surge oscillation in the test rig are identified, and the observed instability is categorized according to the intensity of pressure fluctuations. Based on the test results, the excited pressure waves are clearly the result of surge and not stall. Also, they exhibit the characteristics of mild and classic surge instead of deep surge. Finally, the change in the compressor performance due to variation in the impeller tip clearance is experimentally examined, and the results support the potential of the tip clearance modulation for the control of compressor surge. This is the first such demonstration of the feasibility of surge control of a compressor using active magnetic bearings.

  17. Flow in a Low Specific Speed Centrifugal Pump Using PIV

    Directory of Open Access Journals (Sweden)

    Cui Dai

    2013-01-01

    Full Text Available The interflow plays important roles in centrifugal pump design. In order to study the effect of rotation and z-axis on internal flow, two-dimensional particle image velocimetry (PIV measurements have been performed to measure the steady velocity field on three planes in all impeller passages of a low specific-speed centrifugal pump. The results show that the relative velocity flows in blade passages are obviously different in terms of the positions of the blade relative to the tongue. The interaction between the impeller and tongue changes the occurrence and development of low velocity region with time. From shroud to hub, the relative velocity gradually increases, and the minimum value moves toward the suction surface. On the midplane, the magnitude increases with increased flow rate from pressure surface to suction surface, while at the shroud and hub, the measured velocity first increases with decreased flow rate from the blade pressure surface to nearly ζ = 0.5 to 0.6.

  18. Centrifugal compression of soft particle packings: theory and experiment.

    Science.gov (United States)

    Nordstrom, K N; Verneuil, E; Ellenbroek, W G; Lubensky, T C; Gollub, J P; Durian, D J

    2010-10-01

    An exact method is developed for computing the height of an elastic medium subjected to centrifugal compression, for arbitrary constitutive relation between stress and strain. Example solutions are obtained for power-law media and for cases where the stress diverges at a critical strain--for example as required by packings composed of deformable but incompressible particles. Experimental data are presented for the centrifugal compression of thermo-responsive N-isopropylacrylamide (NIPA) microgel beads in water. For small radial acceleration, the results are consistent with Hertzian elasticity, and are analyzed in terms of the Young elastic modulus of the bead material. For large radial acceleration, the sample compression asymptotes to a value corresponding to a space-filling particle volume fraction of unity. Therefore we conclude that the gel beads are incompressible, and deform without deswelling. In addition, we find that the Young elastic modulus of the particulate gel material scales with cross-link density raised to the power 3.3±0.8, somewhat larger than the Flory expectation.

  19. In-vitro assessment of centrifugal pumps for ventricular assist.

    Science.gov (United States)

    Jakob, H; Kutschera, Y; Palzer, B; Prellwitz, W; Oelert, H

    1990-08-01

    Currently two major types of centrifugal pumps are commercially available for ventricular assist: the Biomedicus-cone (Group I) and the Centrimed-impeller pump (now Sarns 3M) (Group II). To compare them for blood trauma and hemolysis, an in-vitro experiment was designed with a Stöckert roller pump as a standard control (Group III). The in-vitro circuit was constructed consisting of a pump head, electromagnetic flow probe, polyvinyl chloride tubing and a reservoir, identical for all groups. Human ACD blood was used for priming and was circulated with a flow rate of 2 L/min for 24 h. Blood samples were taken at 0, 1, 3, 6, 12, and 24 h and zero control values were subtracted from the resulting data per time interval. Among the 16 parameters studied, a highly significant difference in favor of Group I was found for glutamate oxalacetate transaminase (GOT) and lactate dehydrogenase (p less than 0.0001) and for the free plasma hemoglobin (p less than 0.0001) after 12 and 24 h, respectively. The hemolytic index (Allen) again was lowest for group I in contrast to Groups II and III (0.012 versus 0.060 and 1.70) after 24 h. All other parameters studied did not render significant differences between the systems tested. The authors conclude that the Biomedicus pump currently is the least traumatic centrifugal pump for ventricular assist.

  20. Platelet function and hemolysis in centrifugal pumps: in vitro investigations.

    Science.gov (United States)

    Steines, D; Westphal, D; Göbel, C; Reul, H; Rau, G

    1999-08-01

    The effects of centrifugal pumps on blood components other than erythrocytes, namely platelets and their interaction with the coagulation system, are not very well known. In a comparative study with three centrifugal pumps (BioMedicus BP-80, St. Jude Isoflow, and Sarns Delphin) and the Stockert roller pump hemolysis, platelet counts, thromboplastin and partial thromboplastin times, as well as resonance thrombography (RTG) parameters for the assessment of platelet and coagulation function were evaluated in vitro. Normalized indices of hemolysis (NIH) with ACD anticoagulation after 360 minutes were 0.008+/-0.004 (Isoflow), 0.018+/-0.017 (BP-80), 0.085+/-0.051 (Delphin), and 0.049+/-0.010 g/1001 (roller pump). Plasmatic coagulation was activated in all circuits. Platelet function was severely inhibited by the BP-80, indicated by increase in RTG platelet time to 358%+/-150% of initial values compared to 42%+/-29% (Isoflow), 40%+/-20% (Delphin), and 12%+/-10% (roller pump). Fibrin polymerization was affected similarly. The large surface area of the BP-80 leads to an extensive activation of platelets and plasminogen.

  1. Numerical Study of Unsteady Flow in Centrifugal Cold Compressor

    Science.gov (United States)

    Zhang, Ning; Zhang, Peng; Wu, Jihao; Li, Qing

    In helium refrigeration system, high-speed centrifugal cold compressor is utilized to pumped gaseous helium from saturated liquid helium tank at low temperature and low pressure for producing superfluid helium or sub-cooled helium. Stall and surge are common unsteady flow phenomena in centrifugal cold compressors which severely limit operation range and impact efficiency reliability. In order to obtain the installed range of cold compressor, unsteady flow in the case of low mass flow or high pressure ratio is investigated by the CFD. From the results of the numerical analysis, it can be deduced that the pressure ratio increases with the decrease in reduced mass flow. With the decrease of the reduced mass flow, backflow and vortex are intensified near the shroud of impeller. The unsteady flow will not only increase the flow loss, but also damage the compressor. It provided a numerical foundation of analyzing the effect of unsteady flow field and reducing the flow loss, and it is helpful for the further study and able to instruct the designing.

  2. LISSAT Analysis of a Generic Centrifuge Enrichment Plant

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, H; Elayat, H A; O?Connell, W J; Szytel, L; Dreicer, M

    2007-05-31

    The U.S. Department of Energy (DOE) is interested in developing tools and methods for use in designing and evaluating safeguards systems for current and future plants in the nuclear power fuel cycle. The DOE is engaging several DOE National Laboratories in efforts applied to safeguards for chemical conversion plants and gaseous centrifuge enrichment plants. As part of the development, Lawrence Livermore National Laboratory has developed an integrated safeguards system analysis tool (LISSAT). This tool provides modeling and analysis of facility and safeguards operations, generation of diversion paths, and evaluation of safeguards system effectiveness. The constituent elements of diversion scenarios, including material extraction and concealment measures, are structured using directed graphs (digraphs) and fault trees. Statistical analysis evaluates the effectiveness of measurement verification plans and randomly timed inspections. Time domain simulations analyze significant scenarios, especially those involving alternate time ordering of events or issues of timeliness. Such simulations can provide additional information to the fault tree analysis and can help identify the range of normal operations and, by extension, identify additional plant operational signatures of diversions. LISSAT analyses can be used to compare the diversion-detection probabilities for individual safeguards technologies and to inform overall strategy implementations for present and future plants. Additionally, LISSAT can be the basis for a rigorous cost-effectiveness analysis of safeguards and design options. This paper will describe the results of a LISSAT analysis of a generic centrifuge enrichment plant. The paper will describe the diversion scenarios analyzed and the effectiveness of various safeguards systems alternatives.

  3. Centrifugo-pneumatic multi-liquid aliquoting - parallel aliquoting and combination of multiple liquids in centrifugal microfluidics.

    Science.gov (United States)

    Schwemmer, F; Hutzenlaub, T; Buselmeier, D; Paust, N; von Stetten, F; Mark, D; Zengerle, R; Kosse, D

    2015-08-07

    The generation of mixtures with precisely metered volumes is essential for reproducible automation of laboratory workflows. Splitting a given liquid into well-defined metered sub-volumes, the so-called aliquoting, has been frequently demonstrated on centrifugal microfluidics. However, so far no solution exists for assays that require simultaneous aliquoting of multiple, different liquids and the subsequent pairwise combination of aliquots with full fluidic separation before combination. Here, we introduce the centrifugo-pneumatic multi-liquid aliquoting designed for parallel aliquoting and pairwise combination of multiple liquids. All pumping and aliquoting steps are based on a combination of centrifugal forces and pneumatic forces. The pneumatic forces are thereby provided intrinsically by centrifugal transport of the assay liquids into dead end chambers to compress the enclosed air. As an example, we demonstrate simultaneous aliquoting of 1.) a common assay reagent into twenty 5 μl aliquots and 2.) five different sample liquids, each into four aliquots of 5 μl. Subsequently, the reagent and sample aliquots are simultaneously transported and combined into twenty collection chambers. All coefficients of variation for metered volumes were between 0.4%-1.0% for intra-run variations and 0.5%-1.2% for inter-run variations. The aliquoting structure is compatible to common assay reagents with a wide range of liquid and material properties, demonstrated here for contact angles between 20° and 60°, densities between 789 and 1855 kg m(-3) and viscosities between 0.89 and 4.1 mPa s. The centrifugo-pneumatic multi-liquid aliquoting is implemented as a passive fluidic structure into a single fluidic layer. Fabrication is compatible to scalable fabrication technologies such as injection molding or thermoforming and does not require any additional fabrication steps such as hydrophilic or hydrophobic coatings or integration of active valves.

  4. Cardio-postural interactions and short-arm centrifugation.

    Science.gov (United States)

    Blaber, Andrew; Goswami, Nandu; Xu, Da; Laurin, Alexendre

    INTRODUCTION: We are interested in mechanisms associated with orthostatic tolerance. In previous studies we have shown that postural muscles in the calf contribute to both posture and blood pressure regulation during orthostatic stress. In this study we investigated the relationship between cardiovascular and postural muscle control before, during and after short arm human centrifuge (SAHC) up to 2.2 G. METHODS: Eleven healthy young subjects (6 m, 5 f), with no history of cardiovascular disease, falls or orthostatic hypotension, participated. All were familiarized with the SAHC with 10 minutes at 1-G at the feet. Each subject was instrumented in the supine position on the SAHC for beat-to-beat ECG and blood pressure (Portapres derived SBP). Bilateral lower leg EMG was collected from four leg postural muscles: tibialis anterior, medial gastrocnemius, lateral gastrocnemius, and medial soleus. Transdermal differential recording of signals was performed using an 8-channel EMG system, (Myosystem 1200, Noraxon Inc., Arizona, USA). Postural sway data of the body COP was computed from the force and moment data collected with a force platform (Accusway, AMTI, MA, USA). Before and after SAHC, the subject stood on a force platform with their gaze fixed on a point at eye level, closed their eyes and stood quietly for 5 min. A final stand was conducted 30 min after centrifugation with supine rest in between. During clockwise centrifugation (10-min 1g and 10-min 2.2g at the foot) the subjects’ head was hooded and in the dark. The subject’s body was restrained into the rotation arm with a parachute harness and given additional body support with a foot-plate. ECG, EMG and BP data were collected throughout and centre of pressure trajectory (COP) collected during the stand test. Subjects were requested to relax and not to voluntarily contract the leg muscles; however, they were not to suppress contractions as they occurred involuntarily or by reflex. A Continuous Wavelet

  5. A new non-synchronous preparative counter-current centrifuge-the next generation of dynamic extraction/chromatography devices with independent mixing and settling control, which offer a step change in efficiency.

    Science.gov (United States)

    Ignatova, Svetlana; Hawes, David; van den Heuvel, Remco; Hewitson, Peter; Sutherland, Ian A

    2010-01-01

    A new and significantly more robust design of non-synchronous coil planet centrifuge is introduced where the degree of mixing between two immiscible phases can be changed independently from the "g" field required to separate out the phases. A hypothesis that an optimum ratio between the speed of the bobbin and the speed of the rotor can be found to optimise the efficiency of the separation for a given force field is upheld for an intermediate polarity phase system. This paves the way for extensive further research to find the optimum non-synchronous conditions for a range of different phase systems that are desirable for the separation of large molecules, proteins and biologics but can tend to emulsify in the standard "J" type centrifuge systems currently available and routinely in use for aqueous organic phase systems. A step change of up to 30% in resolution and 90% in plate efficiency is demonstrated.

  6. Incidence of electrocardiographic changes during cytapheresis using an intermittent flow centrifuge, haemonetics V50 and a continuous flow centrifuge, AS104.

    Science.gov (United States)

    Komatsu, F; Kajiwara, M

    1997-03-01

    Electrocardiographic (ECG) monitoring was performed during cytapheresis and the incidence of ECG changes was compared between methods of intermittent flow centrifugation using the Haemonetics V50 with apheresis donors and continuous flow centrifugation with the AS104 for peripheral blood stem cell (PBSC) collection from patients. ST depression, inverted T wave and other ECG changes were found in 49 (14.3%) of the 342 cytaphereses carried out by the intermittent flow centrifugation method and in 8 (4.7%) of the 169 PBSC collections by the continuous flow centrifugation method. This difference was significant (P < 0.05). The hemodynamic changes in the procedure with the AS104 seem to be small. This is considered to be important for prevention of serious ST and T wave changes.

  7. Numerical Calculation of the Three-Dimensional Swirling Flow Inside the Centrifugal Pump Volutes

    Directory of Open Access Journals (Sweden)

    E. Cezmi Nursen

    2003-01-01

    Full Text Available The flow inside the volute of a centrifugal pump is threedimensional and, depending upon the position of the inlet relative to the cross-section center line, a single or double swirling flow occurs. The purpose of this study was the calculation of the three-dimensional swirling flow inside the centrifugal pump volute.

  8. PECULIARITIES OF STRUCTURE-FORMATION AT SVS IN MELTED CONDENSED MIXTURES AT INFLUENCE OF CENTRIFUGAL FORCE

    Directory of Open Access Journals (Sweden)

    V. V. Hubovich

    2007-01-01

    Full Text Available The influence of centrifugal force on dynamics of the burning wave spread and the carbide particles distribution in metallic alloy in the process of SVS-casting is considered. It was concluded that centrifugal force can be used for production of materials with gradient of the hardening particles concentration.

  9. The theory of the centrifugal mechanism of feeding-in in bent crystals

    OpenAIRE

    2001-01-01

    For a particle channeled in the bent crystal planes (axes), the phenomenon of "bending dechanneling", which is a particle transition to a random state due to centrifugal force, is well known. We consider an analytical theory of the reverse phenomenon, i.e., feeding from a random state to a channeled state due to centrifugal force in a crystal with variable curvature.

  10. Concept designs of nonrotating-type centrifugal blood pump and basic study on output characteristics of the oscillating disk-type centrifugal pump.

    Science.gov (United States)

    Kabei, N; Tuichiya, K; Sakurai, Y

    1994-09-01

    When designing a turbo-type blood pump as an artificial heart, the gap between a rotating shaft and a pump housing should be perfectly sealed to prevent any leakage or contamination through a seal. In addition, blood coagulation in a blood chamber must be avoided. To overcome these problems, we proposed five different nonrotating-type turbo pumps: a caudal-fin-type axial-flow pump, a caudal-fin-type centrifugal pump, a nutating-column-type centrifugal pump, a nutating-collapsible-tube-type centrifugal pump, and an oscillating-disk-type centrifugal pump. We selected and developed the oscillating-disk-type centrifugal pump that consists of a disk, a driving rod, a seal, an oscillation mechanism, and a pump housing. The disk is mounted on the end of the rod, which is connected to a high-speed DC motor through an oscillation mechanism. The rod and the disk do not rotate, but they oscillate in the pump housing. This movement of the disk generates forward fluid flow around the axis (i.e., the rotational fluid flow). Centrifugal force due to fluid rotation supports the pressure difference between the outlet and the inlet. The diameter of the disk is 39 mm, the maximum inner diameter of the pump housing is 40 mm, and the volume of the blood chamber for 25 degrees' oscillation is 16.9 ml. The performance of the pump was tested in a mock circulatory system.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Fictional Separation Logic

    DEFF Research Database (Denmark)

    Jensen, Jonas Buhrkal; Birkedal, Lars

    2012-01-01

    , separation means physical separation. In this paper, we introduce \\emph{fictional separation logic}, which includes more general forms of fictional separating conjunctions P * Q, where "*" does not require physical separation, but may also be used in situations where the memory resources described by P and Q...

  12. Principles of separation: indications and therapeutic targets for plasma exchange.

    Science.gov (United States)

    Williams, Mark E; Balogun, Rasheed A

    2014-01-01

    Extracorporeal "blood purification," mainly in the form of hemodialysis has been a major portion of the clinical activity of many nephrologists for the past 5 decades. A possibly older procedure, therapeutic plasma exchange, separates and then removes plasma as a method of removing pathogenic material from the patient. In contrast to hemodialysis, therapeutic plasma exchange preferentially removes biologic substances of high molecular weight such as autoantibodies or alloantibodies, antigen-antibody complexes, and Ig paraproteins. These molecular targets may be cleared through two alternative procedures: centrifugal separation and membrane separation. This review presents operational features of each procedure, with relevance to the nephrologist. Kinetics of removal of these plasma constituents are based on the principles of separation by the apheresis technique and by features specific to each molecular target, including their production and compartmentalization in the body. Molecular targets for common renal conditions requiring therapeutic plasma exchange are also discussed in detail.

  13. The potential of centrifugal casting for the production of near net shape uranium parts

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, E. [United States Air Force Academy, Colorado Springs, CO (US). Dept. of Engineering Mechanics

    1993-09-01

    This report was written to provide a detailed summary of a literature survey on the near net shape casting process of centrifugal casting. Centrifugal casting is one potential casting method which could satisfy the requirements of the LANL program titled Near Net Shape Casting of Uranium for Reduced Environmental, Safety and Health Impact. In this report, centrifugal casting techniques are reviewed and an assessment of the ability to achieve the near net shape and waste minimization goals of the LANL program by using these techniques is made. Based upon the literature reviewed, it is concluded that if properly modified for operation within a vacuum, vertical or horizontal centrifugation could be used to safely cast uranium for the production of hollow, cylindrical parts. However, for the production of components of geometries other than hollow tubes, vertical centrifugation could be combined with other casting methods such as semi-permanent mold or investment casting.

  14. Numerical study of a high-speed miniature centrifugal compressor

    Science.gov (United States)

    Li, Xiaoyi

    A miniature centrifugal compressor is a key component of reverse Brayton cycle cryogenic cooling system. The system is commonly used to generate a low cryogenic temperature environment for electronics to increase their efficiency, or generate, store and transport cryogenic liquids, such as liquid hydrogen and oxygen, where space limit is also an issue. Because of space limitation, the compressor is composed of a radial IGV, a radial impeller and an axial-direction diffuser (which reduces the radial size because of smaller diameter). As a result of reduction in size, rotating speed of the impeller is as high as 313,000 rpm, and Helium is used as the working fluid, in order to obtain the required static pressure ratio/rise. Two main characteristics of the compressor---miniature and high-speed, make it distinct from conventional compressors. Higher compressor efficiency is required to obtain a higher COP (coefficient of performance) system. Even though miniature centrifugal compressors start to draw researchers' attention in recent years, understanding of the performance and loss mechanism is still lacking. Since current experimental techniques are not advanced enough to capture details of flow at miniature scale, numerical methods dominate miniature turbomachinery study. This work numerically studied a high speed miniature centrifugal compressor with commercial CFD code. The overall performance of the compressor was predicted with consideration of interaction between blade rows by using sliding mesh model. The law of similarity of turbomachinery was validated for small scale machines. It was found that the specific ratio effect needs to be considered when similarity law is applied. But Reynolds number effect can be neglected. The loss mechanism of each component was analyzed. Loss due to turning bend was significant in each component. Tip leakage loss of small scale turbomachines has more impact on the impeller performance than that of large scale ones. Because the

  15. Use of partially shrouded impeller in a small centrifugal compressor

    Institute of Scientific and Technical Information of China (English)

    Jin Tang; Teemu Turunen-Saaresti; Jaakko Larjola

    2008-01-01

    Numerical analysis is conducted for the 3-dimensional impeller and vaneless diffuser of a small centrifugal compressor. The influence of impeller tip clearance on the flow field of the impeller is investigated. Detailed investigation on the leaking flow across the tip clearance of the impeller shows that the leaking flow rate is higher near the exit of the impeller than that near the inlet of the impeller. Based on this phenomenon, a new partially shrouded impeller is designed. The impeller is shrouded near the exit of the impeller. Numerical results show that the secondary flow region becomes smaller at the exit of the impeller. Better performance is achieved than that with the unshrouded impeller.

  16. Approaches to stable operation of shaftless centrifugal pump

    Science.gov (United States)

    Kawashima, Ryunosuke; Uno, Mitsuo; Kanemoto, Toshiaki

    2009-03-01

    The shaft-less impeller of the centrifugal pump, which is driven by the magnetic induction, was developed. The impeller rotates under the floating condition without any control device. The floating condition of the impeller is realized by utilizing the pressure in pump casing. The pump performance and the rotational behavior of the impeller were investigated experimentally. It has found that the floating position of the impeller become quite unstable in a partial flow rate operation. And the pressure distribution at the casing wall affects the rotational posture of the impeller. This paper presents the effect of the casing treatment on the rotational posture of the impeller and the pressure distribution. The reasonable casing treatment is available for the stable rotational posture of the impeller.

  17. Centrifugal photovoltaic and photogalvanic effects driven by structured light

    CERN Document Server

    Wätzel, Jonas

    2016-01-01

    Much efforts are devoted to material structuring in a quest to enhance the photovoltaic effect. We show that structuring light in a way it transfers orbital angular momentum to semiconductor-based rings results in a steady charge accumulation at the outer boundaries that be utilized for the generation of an open circuit voltage or a photogalvanic (bulk photovoltaic) type current. This effect which stems both from structuring light and matter (confinement potentials), can be magnified even at fixed moderate intensities, by increasing the orbital angular momentum of light which strengthens the effective centrifugal potential that repels the charge outwards. Based on a full numerical time propagation of the carriers wave functions in the presence of light pulses we demonstrate how the charge buildup leads to a useable voltage or directed photocurrent whose amplitudes and directions are controllable by the light pulse parameters.

  18. Centrifugal experimental study of suction bucket foundations under dynamic loading

    Institute of Scientific and Technical Information of China (English)

    Xiaobing Lu; Yongren Wu; Bintian Jiao; Shuyun Wang

    2007-01-01

    Centrifugal experiments were carded out to investigate the responses of suction bucket foundations under horizontal and vertical dynamic loading. It is shown that when the loading amplitude is over a critical value, the sand at the upper part around the bucket is softened or even liq-uefied. The excess pore pressure decreases from the upper part to the lower part of the sand layer in the vertical direc-tion and decreases radially from the bucket's side wall in the horizontal direction. Large settlements of the bucket and the sand layer around the bucket are induced by dynamic load-ing. The dynamic responses of the bucket with smaller height (the same diameter) are heavier.

  19. Effect of Fluid Viscosity on Centrifugal Pump Performance

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nohhyeong [GS Caltex Corporation, Daejeon (Korea, Republic of)

    2013-06-15

    The characteristics of centrifugal pump performance according to fluid viscosity change were studied experimentally. A small volute pump with low specific speed was tested by changing the viscosity of an aqueous solution of sugar and glycerin, which is considered a Newtonian fluid. After finishing the test, the total head, shaft horsepower, and pump efficiency were compared with those of a water pump. The results are summarized as follows: when the fluid viscosity is increased, the shut-off head shows very little change but the total head decreases gradually as the flow increases, and this makes the H-Q curve leaning rapidly, and when the fluid viscosity is increased, the shaft horsepower shows very little change at the shutoff condition; however, the shaft horsepower increases more rapidly with an increase in the flow and viscosity.

  20. Stopping intense beams of internally cold molecules via centrifugal forces

    Science.gov (United States)

    Wu, Xing; Gantner, Thomas; Zeppenfeld, Martin; Chervenkov, Sotir; Rempe, Gerhard

    2016-05-01

    Cryogenic buffer-gas cooling produces intense beams of internally cold molecules. It offers a versatile source for studying collision dynamics and reaction pathways in the cold regime, and could open new avenues for controlled chemistry, precision spectroscopy, and exploration of fundamental physics. However, an efficient deceleration of these beams still presents a challenge. Here, we demonstrate that intense and continuous beams of electrically guided molecules produced by a cryogenic buffer-gas cell can be brought to a halt by the centrifugal force in a rotating frame. Various molecules (e.g. CH3F and CF3CCH) are decelerated to below 20m /s at a corresponding output intensity of ~ 6 ×109mm-2 .s-1 . In addition, our RF-resonant depletion detection shows that up to 90 % rotational-state purity can be achieved in the so-produced slow molecular beams.

  1. Centrifugal photovoltaic and photogalvanic effects driven by structured light.

    Science.gov (United States)

    Wätzel, J; Berakdar, J

    2016-02-22

    Much efforts are devoted to material structuring in a quest to enhance the photovoltaic effect. We show that structuring light in a way it transfers orbital angular momentum to semiconductor-based rings results in a steady charge accumulation at the outer boundaries that can be utilized for the generation of an open circuit voltage or a photogalvanic (bulk photovoltaic) type current. This effect which stems both from structuring light and matter confinement potentials, can be magnified even at fixed moderate intensities, by increasing the orbital angular momentum of light which strengthens the effective centrifugal potential that repels the charge outwards. Based on a full numerical time propagation of the carriers wave functions in the presence of light pulses we demonstrate how the charge buildup leads to a useable voltage or directed photocurrent whose amplitudes and directions are controllable by the light pulse parameters.

  2. Ultrasound treatment of centrifugally atomized 316 stainless steel powders

    Science.gov (United States)

    Rawers, James C.; McCune, Robert A.; Dunning, John S.

    1991-12-01

    The Bureau of Mines is studying the surface characteristics of rapidly solidified powders and the potential for surface modification of fine powders prior to consolidation. The surface modification and work hardening of fine powders were accomplished by applying high-energy ultrasound to centrifugally atomized austenitic 316 stainless steel powders suspended in liquid media. Cavitation implosion changed the surface morphology, hammering the surface and occasionally fretting off microchips of work-hardened metal. Ultrasound-cavitation work-hardened metal powder surfaces producing a strained, duplex austenite face-centered cubic (fcc)-martensite body-centered tetragonal (bct) phase structure. The amount of work hardening depended upon the quantity of ultrasound energy used, considering both power level and experimental time. Work hardening was relatively independent of the liquid media used.

  3. A multiple disk centrifugal pump as a blood flow device.

    Science.gov (United States)

    Miller, G E; Etter, B D; Dorsi, J M

    1990-02-01

    A multiple disk, shear force, valveless centrifugal pump was studied to determine its suitability as a blood flow device. A pulsatile version of the Tesla viscous flow turbine was designed by modifying the original steady flow pump concept to produce physiological pressures and flows with the aid of controlling circuitry. Pressures and flows from this pump were compared to a Harvard Apparatus pulsatile piston pump. Both pumps were connected to an artificial circulatory system. Frequency and systolic duration were varied over a range of physiological conditions for both pumps. The results indicated that the Tesla pump, operating in a pulsatile mode, is capable of producing physiologic pressures and flows similar to the Harvard pump and other pulsatile blood pumps.

  4. Operational Experience with a Cryogenic Axial-Centrifugal Compressor

    CERN Document Server

    Decker, L; Löhlein, K; Purtschert, W; Ziegler, B L; Lebrun, P; Tavian, L; Brunovsky, I; Tucek, L

    1998-01-01

    The Large Hadron Collider (LHC), presently under construction at CERN, requires large refrigeration capacity at 1.8 K. Compression of gaseous helium at cryogenic temperatures is therefore inevitable. Together with subcontractors, Linde Kryotechnik has developed a prototype machine. This unit is based on a cryogenic axial-centrifugal compressor, running on ceramic ball bearings and driven by a variable-frequency electrical motor operating at ambient temperature. Integrated in a test facility for superconducting magnets the machine has been commissioned without major problems and successfully gone through the acceptance test in autumn 1995. Subsequent steps were initiated to improve efficiency of this prototype. This paper describes operating experience gained so far and reports on measured performance prior to and after constructional modifications.

  5. Performance Improvement of a Centrifugal Compressor by Passive Means

    Directory of Open Access Journals (Sweden)

    N. Sitaram

    2012-01-01

    Full Text Available The present experimental investigation deals with performance improvement of a low-speed centrifugal compressor by inexpensive passive means such as turbulence generator placed at different positions and partial shroud near the rotor blade tip. The experiments are carried out at three values of tip clearance, namely 2.2%, 5.1%, and 7.9% of rotor blade height at the exit. Performance tests are carried out for a total of 13 configurations. From these measurements, partial shroud is found to give the best performance. The improvement in the compressor performance may be due to the reduction of tip leakage flows by the small extension of partial shroud (2 mm on the pressure surface side. Although there is nominal change in performance due to turbulence generator (TG, TG has beneficial effect of increased operating range.

  6. Approaches to Stable Operation of Shaftless Centrifugal Pump

    Institute of Scientific and Technical Information of China (English)

    Ryunosuke Kawashima; Mitsuo Uno; Toshiaki Kanemoto

    2009-01-01

    The shaft-less impeller of the centrifugal pump, which is driven by the magnetic induction, was developed. The impeller rotates under the floating condition without any control device. The floating condition of the impeller is realized by utilizing the pressure in pump casing. The pump performance and the rotational behavior of the im-peUer were investigated experimentally. It has found that the floating position of the impeller become quite unsta-ble in a partial flow rate operation. And the pressure distribution at the casing wall affects the rotational posture of the impeller. This paper presents the effect of the casing treatment on the rotational posture of the impeller and the pressure distribution. The reasonable casing treatment is available for the stable rotational posture of the impeller.

  7. A cryogenic axial-centrifugal compressor for superfluid helium refrigeration

    CERN Document Server

    Decker, L; Schustr, P; Vins, M; Brunovsky, I; Lebrun, P; Tavian, L

    1997-01-01

    CERN's new project, the Large Hadron Collider (LHC), will use superfluid helium as coolant for its high-field superconducting magnets and therefore require large capacity refrigeration at 1.8 K. This may only be achieved by subatmospheric compression of gaseous helium at cryogenic temperature. To stimulate development of this technology, CERN has procured from industry prototype Cold Compressor Units (CCU). This unit is based on a cryogenic axial-centrifugal compressor, running on ceramic ball bearings and driven by a variable-frequency electrical motor operating under low-pressure helium at ambient temperature. The machine has been commissioned and is now in operation. After describing basic constructional features of the compressor, we report on measured performance.

  8. A Novel Aerodynamic Design Method for Centrifugal Compressor Impeller

    Directory of Open Access Journals (Sweden)

    Mahdi Nili-Ahmadabadi

    2014-01-01

    Full Text Available This paper describes a new quasi-3D design method for centrifugal compressor impeller. The method links up a novel inverse design algorithm, called Ball-Spine Algorithm (BSA, and a quasi-3D analysis. Euler equation is solved on the impeller meridional plane. The unknown boundaries (hub and shroud of numerical domain are iteratively modified by BSA until a target pressure distribution in flow passage is reached. To validate the quasi-3D analysis code, existing compressor impeller is investigated experimentally. Comparison between the quasi-3D analysis and the experimental results shows good agreement. Also, a full 3D Navier-Stokes code is used to analyze the existing and designed compressor numerically. The results show that the momentum decrease near the shroud wall in the existing compressor is removed by hub-shroud modifications resulting an improvement in performance by 0.6 percent.

  9. DETECTION OF CAVITATION IN CENTRIFUGAL PUMP BY VIBRATION METHODS

    Institute of Scientific and Technical Information of China (English)

    NI Yongyan; YUAN Shouqi; PAN Zhongyong; YUAN Jianping

    2008-01-01

    For the purpose of detecting the cavitation of centrifugal pump onsite and real time, the vibration signals on varied operation conditions of both cavitation and non-cavitation obtained through acceleration sensors were analyzed. When cavitation occurs, the cavities near the leading edge of the blade will appear periodic oscillating, which will induce quasi-synchronous vibration. The frequency of the quasi-synchronous vibration symmetrically appears on the two sides of the blade passing frequency, by which the cavitation incipiency can be detected. During the developing process of the cavitation, as the severe complexity of the unsteady flow, it is very difficult to detect the development of cavitation by classical analysis methods. Fractal method of Higuchi is successfully used for detecting the incipiency, fully development of cavitation and the development between them.

  10. Laser isotope separation and proliferation risks

    Energy Technology Data Exchange (ETDEWEB)

    Fuss, Werner

    2015-02-15

    There is an ongoing discussion on the proliferation danger of laser enrichment of uranium by the Silex process. Here this risk is compared to that of other processes, in particular centrifuges. The two methods need a similar size of the plant for a comparable production rate (in separative work units per year) and the time and costs for their construction do not differ much. This conclusion from published material does not depend on technical details of Silex. But enough details are known to allow for additional conclusions: Whereas the selectivity (enrichment factor) in the Silex process seems higher, the energy consumption is probably larger. Due to the laser's repetition rate being insufficient for the molecular beam, the method has probably a low depletion factor; this is a serious disadvantage for cascading for high enrichment such as for bomb uranium, although it may be acceptable for low enrichment without cascading for reactor purposes.

  11. Rigorous buoyancy driven bubble mixing for centrifugal microfluidics.

    Science.gov (United States)

    Burger, S; Schulz, M; von Stetten, F; Zengerle, R; Paust, N

    2016-01-21

    We present batch-mode mixing for centrifugal microfluidics operated at fixed rotational frequency. Gas is generated by the disk integrated decomposition of hydrogen peroxide (H2O2) to liquid water (H2O) and gaseous oxygen (O2) and inserted into a mixing chamber. There, bubbles are formed that ascent through the liquid in the artificial gravity field and lead to drag flow. Additionaly, strong buoyancy causes deformation and rupture of the gas bubbles and induces strong mixing flows in the liquids. Buoyancy driven bubble mixing is quantitatively compared to shake mode mixing, mixing by reciprocation and vortex mixing. To determine mixing efficiencies in a meaningful way, the different mixers are employed for mixing of a lysis reagent and human whole blood. Subsequently, DNA is extracted from the lysate and the amount of DNA recovered is taken as a measure for mixing efficiency. Relative to standard vortex mixing, DNA extraction based on buoyancy driven bubble mixing resulted in yields of 92 ± 8% (100 s mixing time) and 100 ± 8% (600 s) at 130g centrifugal acceleration. Shake mode mixing yields 96 ± 11% and is thus equal to buoyancy driven bubble mixing. An advantage of buoyancy driven bubble mixing is that it can be operated at fixed rotational frequency, however. The additional costs of implementing buoyancy driven bubble mixing are low since both the activation liquid and the catalyst are very low cost and no external means are required in the processing device. Furthermore, buoyancy driven bubble mixing can easily be integrated in a monolithic manner and is compatible to scalable manufacturing technologies such as injection moulding or thermoforming. We consider buoyancy driven bubble mixing an excellent alternative to shake mode mixing, in particular if the processing device is not capable of providing fast changes of rotational frequency or if the low average rotational frequency is challenging for the other integrated fluidic operations.

  12. Approach to novel design of CO2 based centrifugal compressor

    Directory of Open Access Journals (Sweden)

    Kura Tomasz

    2016-01-01

    Full Text Available Even though turbomachinery design issues have been investigated almost since the beginning of engineering, its optimization process is still important. With the development of refrigeration devices and ORC based distributed generation facilities, a need for efficient and low-energy compressors and turbines became even more demanding. Such machines working with typical fluid, like air, are well described, but there is a room regarding the fluids like CO2, vapour of organic fluids, etc. The main objective of present studies is to propose a numerical model of the centrifugal compressor, with CO2 as the working fluid. Such unit may be a part of refrigeration cycle. Commonly, the scroll or piston compressors are used in such cases, however some discussed disadvantages show that the novel designs should be looked for. Properly designed centrifugal compressors can have higher efficiency than the presently used. Three dimensional analyses of proposed geometries were conducted – using a model including heat, mass and momentum conservation laws as well as ideal gas law. Verification of the proposed mesh and results was performed in the basis of values obtained using theoretical and empirical equations. With about 700 000 control volumes in the validated model, error of the results was no higher than 5%, with only about 1% in regards to the thermal parameters. Two design proposals were analysed, with performance maps as the main comparison factor. Apart from performance characteristics, the pressure and velocity fields were presented, showing the process of flow structure optimization. The main goal was to reduce negative effects of pressure and velocity gradients on the performance. Proposed precursory design might be a good starting point for further development of compressors. The results of numerical analysis were promising and shows the possibility of proposed design usage in practical applications, however to obtain deep understanding of the

  13. Shunted Piezoelectric Vibration Damping Analysis Including Centrifugal Loading Effects

    Science.gov (United States)

    Min, James B.; Duffy, Kirsten P.; Provenza, Andrew J.

    2011-01-01

    Excessive vibration of turbomachinery blades causes high cycle fatigue problems which require damping treatments to mitigate vibration levels. One method is the use of piezoelectric materials as passive or active dampers. Based on the technical challenges and requirements learned from previous turbomachinery rotor blades research, an effort has been made to investigate the effectiveness of a shunted piezoelectric for the turbomachinery rotor blades vibration control, specifically for a condition with centrifugal rotation. While ample research has been performed on the use of a piezoelectric material with electric circuits to attempt to control the structural vibration damping, very little study has been done regarding rotational effects. The present study attempts to fill this void. Specifically, the objectives of this study are: (a) to create and analyze finite element models for harmonic forced response vibration analysis coupled with shunted piezoelectric circuits for engine blade operational conditions, (b) to validate the experimental test approaches with numerical results and vice versa, and (c) to establish a numerical modeling capability for vibration control using shunted piezoelectric circuits under rotation. Study has focused on a resonant damping control using shunted piezoelectric patches on plate specimens. Tests and analyses were performed for both non-spinning and spinning conditions. The finite element (FE) shunted piezoelectric circuit damping simulations were performed using the ANSYS Multiphysics code for the resistive and inductive circuit piezoelectric simulations of both conditions. The FE results showed a good correlation with experimental test results. Tests and analyses of shunted piezoelectric damping control, demonstrating with plate specimens, show a great potential to reduce blade vibrations under centrifugal loading.

  14. Separation Anxiety (For Parents)

    Science.gov (United States)

    ... Feeding Your 1- to 2-Year-Old Separation Anxiety KidsHealth > For Parents > Separation Anxiety A A A ... both of you get through it. About Separation Anxiety Babies adapt pretty well to other caregivers. Parents ...

  15. Preparative purification of plasmin activity stimulating phenolic derivatives from Gastrodia elata using centrifugal partition chromatography.

    Science.gov (United States)

    Jeon, Je-Seung; Kim, Jeeyoung; Park, Soyoung; Ryou, Chongsuk; Kim, Chul Young

    2016-06-01

    Gastrodia rhizome, a dried and steamed tuber of Gastrodia elata Blume (Orchidaceae), has been traditionally used in Korea, China and Japan for the treatment of neurological and nervous disorders such as headaches, dizziness, vertigo and convulsive illnesses. The ethyl acetate and water extracts of G. elata stimulated plasmin activity. The active ethyl acetate fraction was subjected to centrifugal partition chromatography (CPC) with a two-phase solvent system, composed of n-hexane-ethyl acetate-methanol-water (3:7:4:6, v/v) followed by semi-preparative HPLC purification to separate active compounds and the water fraction was purified by Diaion HP-20 resin and semi-preparative HPLC. In ethyl acetate extract, 4-hydroxybenzyl alcohol (1), 4-hydroxybenzoic acid (2), 4-hydroxybenzaldehyde (3), 4-ethoxymethylphenol (4), 4,4'-oxybis(methylene)diphenol (5) and 4,4'-methylenediphenol (6) were obtained with high purities. Parishin (7) and parishin B (8) were isolated from water extract. Among isolated compounds, 4-hydroxybenzyl alcohol (1), 4-hydroxybenzaldehyde (3) and 4-ethoxymethylphenol (4) significantly stimulated plasmin activity. Copyright © 2015 John Wiley & Sons, Ltd.

  16. In-situ protein determination to monitor contamination in a centrifugal partition chromatograph.

    Science.gov (United States)

    Bouiche, Feriel; Faure, Karine

    2017-02-24

    Centrifugal partition chromatography (CPC) works with biphasic liquid systems including aqueous two-phase systems. Metallic rotors are able to retain an aqueous stationary phase able to purify proteins. But the adhesion of proteins to solid surface may pose a cross-contamination risk during downstream processes. So it is of utmost importance to ensure the cleanliness of the equipment and detect possible protein contamination in a timely manner. Thereby, a direct method that allows the determination of the effective presence of proteins and the extent of contamination in the metallic CPC rotors was developed. This in-situ method is derived from the Amino Density Estimation by Colorimetric Assay (ADECA) which is based on the affinity of a dye, Coomassie Brillant Blue (CBB), with protonated N(+) groups of the proteins. In this paper, the ADECA method was developed dynamically, on a 25 mL stainless-steel rotor with various extents of protein contaminations using bovine serum albumin (BSA) as a fouling model. The eluted CBB dye was quantified and found to respond linearly to BSA contamination up to 70 mg injected. Limits of detection and quantification were recorded as 0.9 mg and 3.1 mg, respectively. While the non-specific interactions between the dye and the rotor cannot currently be neglected, this method allows for in situ determination of proteins contamination and should contribute to the development of CPC as a separation tool in protein purification processes.

  17. Effect of the Unsteadiness on the Diffuser Flow in a Transonic Centrifugal Compressor Stage

    Directory of Open Access Journals (Sweden)

    N. Bulot

    2009-01-01

    Full Text Available The study is focused on the analysis of the flow structure within the vaned diffuser of a transonic high-pressure centrifugal compressor stage. The analyzed time-dependent flow field comes from unsteady computations of the stage using a 3D Navier-Stokes code with a phase-lagged technique, at an operating point close to the design point. A good comparison with available experimental data allowed the use of CFD for investigating the details of the flow in order to assess the effect of the unsteadiness in the diffuser flow development. Applying various data processing techniques, it is shown that the unsteadiness is due to the jet and wake flow structure emerging from the radial impeller and to the pressure waves brought about by the interaction between the vane bow shock wave and the impeller blade. The interaction between the pressure waves and the vane pressure side boundary layer leads to a pulsating behavior of separated bubbles within the diffuser. The pressure waves are similar in shape and strength whatever the blade height. The observed change in the flow field from hub to tip is due to migration of the low momentum fluid contained in the wake toward the pressure side/hub corner.

  18. Pig slurry acidification and separation techniques affect soil N and C turnover and N2O emissions from solid, liquid and biochar fractions

    DEFF Research Database (Denmark)

    Gomez Muñoz, Beatriz; Case, Sean; Jensen, Lars Stoumann

    2016-01-01

    the separated solid fractions in soil, but did not affect N2O and CO2 emissions. However acidification reduced soil N and C turnover from the liquid fraction. The use of more advanced separation techniques (flocculation and drainage > decanting centrifuge > screw press) increased N mineralisation from acidified...

  19. 40 CFR 63.5810 - What are my options for meeting the standards for open molding and centrifugal casting operations...

    Science.gov (United States)

    2010-07-01

    ... standards for open molding and centrifugal casting operations at new and existing sources? 63.5810 Section... § 63.5810 What are my options for meeting the standards for open molding and centrifugal casting... (d) of this section to meet the standards for open molding or centrifugal casting operations in...

  20. X-ray tomographic imaging of Al/SiC{sub p} functionally graded composites fabricated by centrifugal casting

    Energy Technology Data Exchange (ETDEWEB)

    Velhinho, A. E-mail: ajv@fct.unl.ptajv@engmateriais.eng.uminho.pt; Sequeira, P.D.; Martins, Rui; Vignoles, G.; Braz Fernandes, F.; Botas, J.D.; Rocha, L.A

    2003-01-01

    The present work refers to an X-ray microtomography experiment aiming at the elucidation of some aspects regarding particle distribution in SiC-particle-reinforced functionally graded aluminium composites. Precursor composites were produced by rheocasting. These were then molten and centrifugally cast to obtain the functionally graded composites. From these, cylindrical samples, around 1 mm in diameter, were extracted, which were then irradiated with a X-ray beam produced at the European Synchrotron Radiation Facility. The 3-D images were obtained in edge-detection mode. A segmentation procedure has been adapted in order to separate the pores and SiC particles from the Al matrix. Preliminary results on the particle and pore distributions are presented.

  1. X-ray tomographic imaging of Al/SiC p functionally graded composites fabricated by centrifugal casting

    Science.gov (United States)

    Velhinho, A.; Sequeira, P. D.; Martins, Rui; Vignoles, G.; Braz Fernandes, F.; Botas, J. D.; Rocha, L. A.

    2003-01-01

    The present work refers to an X-ray microtomography experiment aiming at the elucidation of some aspects regarding particle distribution in SiC-particle-reinforced functionally graded aluminium composites. Precursor composites were produced by rheocasting. These were then molten and centrifugally cast to obtain the functionally graded composites. From these, cylindrical samples, around 1 mm in diameter, were extracted, which were then irradiated with a X-ray beam produced at the European Synchrotron Radiation Facility. The 3-D images were obtained in edge-detection mode. A segmentation procedure has been adapted in order to separate the pores and SiC particles from the Al matrix. Preliminary results on the particle and pore distributions are presented.

  2. In vitro pulsatility analysis of axial-flow and centrifugal-flow left ventricular assist devices.

    Science.gov (United States)

    Stanfield, J Ryan; Selzman, Craig H

    2013-03-01

    Recently, continuous-flow ventricular assist devices (CF-VADs) have supplanted older, pulsatile-flow pumps, for treating patients with advanced heart failure. Despite the excellent results of the newer generation devices, the effects of long-term loss of pulsatility remain unknown. The aim of this study is to compare the ability of both axial and centrifugal continuous-flow pumps to intrinsically modify pulsatility when placed under physiologically diverse conditions. Four VADs, two axial- and two centrifugal-flow, were evaluated on a mock circulatory flow system. Each VAD was operated at a constant impeller speed over three hypothetical cardiac conditions: normo-tensive, hypertensive, and hypotensive. Pulsatility index (PI) was compared for each device under each condition. Centrifugal-flow devices had a higher PI than that of axial-flow pumps. Under normo-tension, flow PI was 0.98 ± 0.03 and 1.50 ± 0.02 for the axial and centrifugal groups, respectively (p centrifugal pumps, respectively (p = 0.01). Under hypotension, PI was 0.73 ± 0.02 and 0.78 ± 0.02 for the axial and centrifugal groups, respectively (p = 0.13). All tested CF-VADs were capable of maintaining some pulsatile-flow when connected in parallel with our mock ventricle. We conclude that centrifugal-flow devices outperform the axial pumps from the basis of PI under tested conditions.

  3. Centrifugal force induces human ligamentum flavum fibroblasts inflammation through activation of JNK and p38 pathways.

    Science.gov (United States)

    Chao, Yuan-Hung; Tsuang, Yang-Hwei; Sun, Jui-Sheng; Sun, Man-Ger; Chen, Ming-Hong

    2012-01-01

    Inflammation has been proposed to be an important causative factor in ligamentum flavum hypertrophy. However, the mechanisms of mechanical load on inflammation of ligamentum flavum remain unclear. In this study, we used an in vitro model of human ligamentum flavum fibroblasts subjected to centrifugal force to elucidate the effects of mechanical load on cultured human ligamentum flavum fibroblasts; we further studied its molecular and biochemical mechanisms. Human ligamentum flavum fibroblasts were obtained from six patients undergoing lumbar spine surgery. Monolayer cultures of human ligamentum flavum fibroblasts were subjected to different magnitudes of centrifugal forces. Cell viability, cell death, biochemical response, and molecular response to centrifugal forces were analyzed. It was found that centrifugal stress significantly suppressed cell viability without inducing cell death. Centrifugal force at 67.1 g/cm(2) for 60 min significantly increases the production of prostaglandin E2 and nitric oxide as well as gene expression of proinflammatory cytokines, including interleukin (IL)-1α, IL-1β and IL-6, showed that centrifugal force-dependent induction of cyclooxygense-2 and inducible NO synthase required JNK and p38 mitogen-activated protein kinase, but not ERK 1/2 activities. This study suggested that centrifugal force does induce inflammatory responses in human ligamentum flavum fibroblasts. The activation of both JNK and p38 mitogen-activated protein kinase mechanotransduction cascades is a crucial intracellular mechanism that mediates cyclooxygense-2/prostaglandin E2 and inducible NO synthase/nitric oxide production.

  4. Isolation of exosomes by differential centrifugation: Theoretical analysis of a commonly used protocol

    Science.gov (United States)

    Livshts, Mikhail A.; Khomyakova, Elena; Evtushenko, Evgeniy G.; Lazarev, Vassili N.; Kulemin, Nikolay A.; Semina, Svetlana E.; Generozov, Edward V.; Govorun, Vadim M.

    2015-11-01

    Exosomes, small (40-100 nm) extracellular membranous vesicles, attract enormous research interest because they are carriers of disease markers and a prospective delivery system for therapeutic agents. Differential centrifugation, the prevalent method of exosome isolation, frequently produces dissimilar and improper results because of the faulty practice of using a common centrifugation protocol with different rotors. Moreover, as recommended by suppliers, adjusting the centrifugation duration according to rotor K-factors does not work for “fixed-angle” rotors. For both types of rotors - “swinging bucket” and “fixed-angle” - we express the theoretically expected proportion of pelleted vesicles of a given size and the “cut-off” size of completely sedimented vesicles as dependent on the centrifugation force and duration and the sedimentation path-lengths. The proper centrifugation conditions can be selected using relatively simple theoretical estimates of the “cut-off” sizes of vesicles. Experimental verification on exosomes isolated from HT29 cell culture supernatant confirmed the main theoretical statements. Measured by the nanoparticle tracking analysis (NTA) technique, the concentration and size distribution of the vesicles after centrifugation agree with those theoretically expected. To simplify this “cut-off”-size-based adjustment of centrifugation protocol for any rotor, we developed a web-calculator.

  5. Fabrication of silk fibroin film using centrifugal casting technique for corneal tissue engineering.

    Science.gov (United States)

    Lee, Min Chae; Kim, Dong-Kyu; Lee, Ok Joo; Kim, Jung-Ho; Ju, Hyung Woo; Lee, Jung Min; Moon, Bo Mi; Park, Hyun Jung; Kim, Dong Wook; Kim, Su Hyeon; Park, Chan Hum

    2016-04-01

    Films prepared from silk fibroin have shown potential as biomaterials in tissue engineering applications for the eye. Here, we present a novel process for fabrication of silk fibroin films for corneal application. In this work, fabrication of silk fibroin films was simply achieved by centrifugal force. In contrast to the conventional dry casting method, we carried out the new process in a centrifuge with a rotating speed of 4000 rpm, where centrifugal force was imposed on an aluminum tube containing silk fibroin solution. In the present study, we also compared the surface roughness, mechanical properties, transparency, and cell proliferation between centrifugal and dry casting method. In terms of surface morphology, films fabricated by the centrifugal casting have less surface roughness than those by the dry casting. For elasticity and transparency, silk fibroin films obtained from the centrifugal casting had favorable results compared with those prepared by dry casting. Furthermore, primary human corneal keratocytes grew better in films prepared by the centrifugal casting. Therefore, our results suggest that this new fabrication process for silk fibroin films offers important potential benefits for corneal tissue regeneration.

  6. Effect of pumping chamber on performance of non-overload centrifugal pump

    Institute of Scientific and Technical Information of China (English)

    谷云庆; 吴登昊; 牟介刚; 蒋兰芳; 代东顺; 施瀚昱; 郑水华

    2015-01-01

    In order to specify the characteristics of un-overloaded centrifugal pumps, the IH100-65-200 pump was chosen as the model pump. Different calculation models for centrifugal pumps were established under different pumping chamber sectional parameters. In the numerical simulation of the centrifugal pumps flow field, the shaft power, head, efficiency, and the changes of the internal flow field under different sectional areas and sectional shapes were studied with the RNGk−εturbulence model, and the influence of the pumping chamber section characteristics of the non-overloaded centrifugal pumps were analyzed. The results show that sectional areas have a significant impact on the non-overload characteristics of centrifugal pumps. The shaft power and head of centrifugal pump are increasing with a lager sectional area, by which the gradient of head curves decreases. The efficiency is improved under a large flow rate condition, but the head and the efficiency are reduced at a small flow rate. It is also observed that the sectional shapes have less influence on the shaft power, the hydraulic performance and flow field characteristics of a centrifugal pump.

  7. Controlling Separation in Turbomachines

    Science.gov (United States)

    Evans, Simon; Himmel, Christoph; Power, Bronwyn; Wakelam, Christian; Xu, Liping; Hynes, Tom; Hodson, Howard

    2010-01-01

    Four examples of flow control: 1) Passive control of LP turbine blades (Laminar separation control). 2) Aspiration of a conventional axial compressor blade (Turbulent separation control). 3) Compressor blade designed for aspiration (Turbulent separation control). 4.Control of intakes in crosswinds (Turbulent separation control).

  8. Solvent System Selection Strategies in Countercurrent Separation

    Science.gov (United States)

    Liu, Yang; Friesen, J. Brent; McAlpine, James B.; Pauli, Guido F.

    2015-01-01

    The majority of applications in countercurrent and centrifugal partition chromatography, collectively known as countercurrent separation, are dedicated to medicinal plant and natural product research. In countercurrent separation, the selection of the appropriate solvent system is of utmost importance as it is the equivalent to the simultaneous choice of column and eluent in liquid chromatography. However, solvent system selection is often laborious, involving extensive partition and/or analytical trials. Therefore, simplified solvent system selection strategies that predict the partition coefficients and, thus, analyte behavior are in high demand and may advance both the science of countercurrent separation and its applications. The last decade of solvent system selection theory and applications are critically reviewed, and strategies are classified according to their data input requirements. This offers the practitioner an up-to-date overview of rationales and methods for choosing an efficient solvent system, provides a perspective regarding their accuracy, reliability, and practicality, and discusses the possibility of combining multiple methods for enhanced prediction power. PMID:26393937

  9. Ultrasound-Assisted Extraction, Centrifugation and Ultrafiltration: Multistage Process for Polyphenol Recovery from Purple Sweet Potatoes

    Directory of Open Access Journals (Sweden)

    Zhenzhou Zhu

    2016-11-01

    Full Text Available This work provides an evaluation of an ultrasound-assisted, combined extraction, centrifugation and ultrafiltration process for the optimal recovery of polyphenols. A purple sweet potato (PSP extract has been obtained using ultrasonic circulating extraction equipment at a power of 840 W, a frequency of 59 kHz and using water as solvent. Extract ultrafiltration, using polyethersulfone (PES, was carried out for the recovery of polyphenol, protein and anthocyanin. Pre-treatment, via the centrifugation of purple sweet potato extract at 2500 rpm over 6 min, led to better polyphenol recovery, with satisfactory protein removal (reused for future purposes, than PSP extract filtration without centrifugation. Results showed that anthocyanin was efficiently recovered (99% from permeate. The exponential model fit well with the experimental ultrafiltration data and led to the calculation of the membrane’s fouling coefficient. The optimization of centrifugation conditions showed that, at a centrifugation speed of 4000 rpm (1195× g and duration of 7.74 min, the optimized polyphenol recovery and fouling coefficient were 34.5% and 29.5 m−1, respectively. The removal of proteins in the centrifugation process means that most of the anthocyanin content (90% remained after filtration. No significant differences in the intensities of the HPLC-DAD-ESI-MS2 peaks were found in the samples taken before and after centrifugation for the main anthocyanins; peonidin-3-feruloylsophoroside-5-glucoside, peonidin-3-caffeoyl-p-hydroxybenzoylsophoroside-5-glucoside, and peonidin-3-caffeoyl-feruloyl sophoroside-5-glucoside. This proves that centrifugation is an efficient method for protein removal without anthocyanin loss. This study considers this process an ultrasound-assisted extraction-centrifugation-ultrafiltration for purple sweet potato valorization in “green” technology.

  10. Expression of myosin heavy-chain mRNA in cultured myoblasts induced by centrifugal force.

    Science.gov (United States)

    Kurokawa, Katsuhide; Sakiyama, Koji; Abe, Shinichi; Hiroki, Emi; Naito, Kaoru; Nakajima, Kazunori; Takeda, Tomotaka; Inoue, Takashi; Ide, Yoshinobu; Ishigami, Keiichi

    2008-11-01

    Ballistic muscle training leads to hypertrophy of fast type fibers and training for endurance induces that of slow type fibers. Numerous studies have been conducted on electrical, extending and magnetic stimulation of cells, but the effect of centrifugal force on cells remains to be investigated. In this study, we investigated the effect of stimulating cultured myoblasts with centrifugal force at different speeds on cell proliferation and myosin heavy-chain (MyHC) mRNA expression in muscle fiber. Stimulation of myoblasts was carried out at 2 different speeds for 20 min using the Himac CT6D, a desk centrifuge, and cells were observed at 1, 3 and 5 days later. Number of cells 1 and 5 days after centrifugal stimulation was significantly larger in the 62.5 x g and 4,170 x g stimulation groups than in the control group. Expression of MyHC-2b mRNA 1 day after centrifugal stimulation was significantly higher in the 2 stimulation groups than in the control group. Almost no expression of MyHC-2a was observed in any group at 1 and 3 days after centrifugal stimulation. However, 5 days after stimulation, MyHC-2a was strongly expressed in the 2 stimulation groups in comparison to the control group. Three days after centrifugal stimulation, expression of MyHC-1 was significantly higher in the 2 stimulation groups than in the control group. The results of this study clarified the effect of different centrifugal stimulation speeds on muscle fiber characteristics, and suggest that centrifugal stimulation of myoblasts enhances cell proliferation.

  11. Accuracy assessment on the analysis of unbound drug in plasma by comparing traditional centrifugal ultrafiltration with hollow fiber centrifugal ultrafiltration and application in pharmacokinetic study.

    Science.gov (United States)

    Zhang, Lin; Zhang, Zhi-Qing; Dong, Wei-Chong; Jing, Shao-Jun; Zhang, Jin-Feng; Jiang, Ye

    2013-11-29

    In present study, accuracy assessment on the analysis of unbound drug in plasma was made by comparing traditional centrifugal ultrafiltration (CF-UF) with hollow fiber centrifugal ultrafiltration (HFCF-UF). We used metformin (MET) as a model drug and studied the influence of centrifugal time, plasma condition and freeze-thaw circle times on the ultrafiltrate volume and related effect on the measurement of MET. Our results demonstrated that ultrafiltrate volume was a crucial factor which influenced measurement accuracy of unbound drug in plasma. For traditional CF-UF, the ultrafiltrate volume cannot be well-controlled due to a series of factors. Compared with traditional CF-UF, the ultrafiltrate volume by HFCF-UF can be easily controlled by the inner capacity of the U-shaped hollow fiber inserted into the sample under enough centrifugal force and centrifugal time, which contributes to a more accurate measurement. Moreover, the developed HFCF-UF method achieved a successful application in real plasma samples and exhibited several advantages including high precision, extremely low detection limit and perfect recovery. The HFCF-UF method offers the advantage of highly satisfactory performance in addition to being simple and fast in pretreatment, with these characteristics being consistent with the practicability requirements in current scientific research.

  12. Comparative Centrifugal Distortion Analysis in Rotational Spectra of Propanol and Isopropanol Molecules

    Science.gov (United States)

    Qajar, Ch. O.; Kazimova, S. B.

    2015-07-01

    We have compared the effect of centrifugal distortion on the rotational spectra of isopropanol and propanol molecules in the microwave frequency range. We identified 61 rotational transitions of the propanol molecule with rotational quantum numbers up to J = 36 inclusive. We show that in order to satisfactorily take into account centrifugal distortion in the isopropanol molecule, it is sufficient to use only the quartic and sextic terms, while in calculating the rotational transitions of the propanol molecule we need to include all the way up to dectic centrifugal distortion constants.

  13. [Usefulness of the Centrifuge Accommodation Module for analyzing gravity responses in plant seedlings].

    Science.gov (United States)

    Hoson, T

    2001-10-01

    Onboard centrifuges are indispensable tools for clarifying the effects of microgravity on various physiological processes in plant seedlings. Centrifuges are basically attached to the incubators designed for the International Space Station (ISS). However, because of the limitation in size, that loaded to the Cell Biology Experiment Facility (CBEF) is usable only to some small seedlings such as Arabidopsis. The Centrifuge Accommodation Module (CAM) has great advantages in the size and the amounts of plant materials feasible to load, the quality of acceleration produced, and the easiness of operation on it. The CAM is an apparatus that characterizes the ISS most and its construction on schedule is highly expected.

  14. Study on High-Speed Centrifugal-Regenerative Pump with an Inducer

    Institute of Scientific and Technical Information of China (English)

    朱祖超; 陈鹰; 金庆明; 黄敦回

    2002-01-01

    The study on high-speed centrifugal-regenerative pumps with an inducer (HCRP) is carried out. Thecombined structure of inducer, centrifugal impeller, and regenerative impeller is presented, and a theoretical parallelcombinatorial hydraulic design method is investigated. The comparative experimental results show that efficiency insmaller capacity region, head coefficient and efficiency in larger capacity region of HCRPs is few lower, much higherand lower than those of high-speed centrifugal pumps, respectively, anci that the suction performance of HCRPs isdetermined only by inducer. HCRPs can be more suitably applied to deliver small-capacity high-head liquids inchemical and petrochemical industries.

  15. EXPERIMENTAL STUDY ON HIGH-SPEED CENTRIFUGAL PUMPS WITH DIFFERENT IMPELLERS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The experimental study is carded out on high-speed centrifugal pumps with three different impellers. The ex-perimental results and analysis show that high-speed centrifugal pumps with a closed complex impeller can achieve thehighest efficiency and the lowest head coefficient followed by those with half-open impeller and open-impeller, and canobtain much easily stable head-capacity characrastic curve, while those with a half-open complex impeller can't. Thecharacteristic curve with a open impeller is almost constant horizontal line before dropping sharply. The results also showthat the axial clearance between pump casing and impeller can influence greatly on the performance of centrifugal pumps.

  16. Hydrodynamic performance and heat generation by centrifugal pumps.

    Science.gov (United States)

    Ganushchak, Y; van Marken Lichtenbelt, W; van der Nagel, T; de Jong, D S

    2006-11-01

    For over a century, centrifugal pumps (CP) have been used in various applications, from large industrial pumps to flow pumps for aquariums. However, the use of CP as blood pumps has a rather short history. Consequently, the hydraulic performance data for a blood CP are limited. The aim of our investigation was to study the hydraulic performance and the heat generation of three commercially available CP: Bio-Medicus Bio-Pump BP80 (Medtronic), Rotaflow (Jostra Medizintechnik), and DeltaStream DP2 (MEDOS Medizintechnik AQ). The study was performed using a circuit primed with a water-glycerin mixture with a dynamic viscosity of 0.00272 pa/s. Pressure-flow curves were obtained by a stepwise stagnation of the pump outlet or inlet. The temperature changes were observed using ThermaCAM SC2000 (Flir Systems). The pumps' performance in close to clinical conditions ('operating region') was analysed in this report. The 'operating region' in the case of the BP80 is positioned around the pressure-flow curve at a pump speed of 3000 rpm. In the case of the Rotaflow, the 'operating region' was between the pump pressure-flow curves at a speed of 3000 and 4000 rpm, and the DP2 was found between 7000 and 8000 rpm. The standard deviation of mean pressure through the pump was used to characterise the stability of the pump. In experiments with outlet stagnation, the BP80 demonstrated high negative association between flow and pressure variability (r = -0.68, p pumps demonstrated significantly higher variability of pressure in experiments with inlet stagnation in comparison to the experiments with outlet stagnation. The rise of relative temperature in the inlet of a pump was closely related to the flow rate. The heating of fluid was more pronounced in the 'zero-flow' mode, especially in experiments with inlet stagnation. In summary, (1) the 'zero-flow' regime, which is described in the manuals of some commercially-available pumps, is the use of the pump outside the allowable operating

  17. Oil-free centrifugal hydrogen compression technology demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Heshmat, Hooshang [Mohawk Innovative Technology Inc., Albany, NY (United States)

    2014-05-31

    One of the key elements in realizing a mature market for hydrogen vehicles is the deployment of a safe and efficient hydrogen production and delivery infrastructure on a scale that can compete economically with current fuels. The challenge, however, is that hydrogen, being the lightest and smallest of gases with a lower viscosity and density than natural gas, readily migrates through small spaces and is difficult to compresses efficiently. While efficient and cost effective compression technology is crucial to effective pipeline delivery of hydrogen, the compression methods used currently rely on oil lubricated positive displacement (PD) machines. PD compression technology is very costly, has poor reliability and durability, especially for components subjected to wear (e.g., valves, rider bands and piston rings) and contaminates hydrogen with lubricating fluid. Even so called “oil-free” machines use oil lubricants that migrate into and contaminate the gas path. Due to the poor reliability of PD compressors, current hydrogen producers often install duplicate units in order to maintain on-line times of 98-99%. Such machine redundancy adds substantially to system capital costs. As such, DOE deemed that low capital cost, reliable, efficient and oil-free advanced compressor technologies are needed. MiTi’s solution is a completely oil-free, multi-stage, high-speed, centrifugal compressor designed for flow capacity of 500,000 kg/day with a discharge pressure of 1200 psig. The design employs oil-free compliant foil bearings and seals to allow for very high operating speeds, totally contamination free operation, long life and reliability. This design meets the DOE’s performance targets and achieves an extremely aggressive, specific power metric of 0.48 kW-hr/kg and provides significant improvements in reliability/durability, energy efficiency, sealing and freedom from contamination. The multi-stage compressor system concept has been validated through full scale

  18. Modeling Platform Dynamics and Physiological Response to Short Arm Centrifugation

    Science.gov (United States)

    1994-03-01

    the heart are modelled as variable capacitances separated by one-way valves. The pulmonic and aortic valves are also modelled as one-way valves. The...CIRCJLATIOU/OUTPUT C ... C ... The chamers of the heart are maodeled as variable capacitances C ... separated by one-way valves. The pulmonic and aortic

  19. Shape-based separation of microparticles with magnetic fields

    Science.gov (United States)

    Wang, Cheng; Zhou, Ran

    2016-11-01

    Precise manipulations, e.g., sorting and focusing, of nonspherical micro-particles in fluidic environment has important applications in the fields of biology sciences and biomedical engineering. However, non-spherical microparticles are hard to manipulate because they tumble in shear flows. Most of existing techniques, including traditional filtration and centrifugation, and recent microfluidic technology, have difficulty in separating microparticles by shape. We demonstrate a novel shape-based separation technique by combining external magnetic fields with pressure-driven flows in a microchannel. Due to the magnetic field, prolate ellipsoidal particles migrate laterally at different speeds than the spherical ones, leading to effective separation. Our experimental investigations reveal the underlying physical mechanism of the observed shape-dependent migration. We find that the magnetic field breaks the rotational symmetry of the nonspherical particles, and induces shape-dependent lift force and migration velocity.

  20. Design concepts for the Centrifuge Facility Life Sciences Glovebox

    Science.gov (United States)

    Sun, Sidney C.; Horkachuck, Michael J.; Mckeown, Kellie A.

    1989-01-01

    The Life Sciences Glovebox will provide the bioisolated environment to support on-orbit operations involving non-human live specimens and samples for human life sceinces experiments. It will be part of the Centrifuge Facility, in which animal and plant specimens are housed in bioisolated Habitat modules and transported to the Glovebox as part of the experiment protocols supported by the crew. At the Glovebox, up to two crew members and two habitat modules must be accommodated to provide flexibility and support optimal operations. This paper will present several innovative design concepts that attempt to satisfy the basic Glovebox requirements. These concepts were evaluated for ergonomics and ease of operations using computer modeling and full-scale mockups. The more promising ideas were presented to scientists and astronauts for their evaluation. Their comments, and the results from other evaluations are presented. Based on the evaluations, the authors recommend designs and features that will help optimize crew performance and facilitate science accommodations, and specify problem areas that require further study.

  1. Axial and Centrifugal Compressor Mean Line Flow Analysis Method

    Science.gov (United States)

    Veres, Joseph P.

    2009-01-01

    This paper describes a method to estimate key aerodynamic parameters of single and multistage axial and centrifugal compressors. This mean-line compressor code COMDES provides the capability of sizing single and multistage compressors quickly during the conceptual design process. Based on the compressible fluid flow equations and the Euler equation, the code can estimate rotor inlet and exit blade angles when run in the design mode. The design point rotor efficiency and stator losses are inputs to the code, and are modeled at off design. When run in the off-design analysis mode, it can be used to generate performance maps based on simple models for losses due to rotor incidence and inlet guide vane reset angle. The code can provide an improved understanding of basic aerodynamic parameters such as diffusion factor, loading levels and incidence, when matching multistage compressor blade rows at design and at part-speed operation. Rotor loading levels and relative velocity ratio are correlated to the onset of compressor surge. NASA Stage 37 and the three-stage NASA 74-A axial compressors were analyzed and the results compared to test data. The code has been used to generate the performance map for the NASA 76-B three-stage axial compressor featuring variable geometry. The compressor stages were aerodynamically matched at off-design speeds by adjusting the variable inlet guide vane and variable stator geometry angles to control the rotor diffusion factor and incidence angles.

  2. Performance of a newly developed implantable centrifugal blood pump.

    Science.gov (United States)

    Tsukiya, T; Taenaka, Y; Tatsumi, E; Takano, H

    2001-01-01

    The performance of the newly developed implantable centrifugal blood pump was investigated in vitro. The pump was developed with the end goal of building a versatile system that includes a left ventricular assist system with an internal secondary battery or an implantable biventricular assist system with two implantable blood pumps. The hydrodynamic characteristics and efficiency of the blood pump were evaluated, and the mechanical damage to the blood caused by the blood pump was assessed through a hemolysis test using fresh goat blood. The pump could generate 120 mm Hg at a flow rate of 5 L/min and a motor speed of 2,500 rpm. The electric input power to the pump was approximately 5 watts under these working conditions. The hemolysis caused by the pump was a bit higher than that by the former model, but stayed within an acceptable range. Performance of the pump in vitro was considered sufficient for a left ventricular assist device, although further design improvement is necessary in terms of hemolysis and system efficiency to improve biocompatibility of the pump.

  3. Centrifugal barrel polishing of 1.3 GHz Nb cavities

    Energy Technology Data Exchange (ETDEWEB)

    Tamashevich, Yegor; Foster, Brian [DESY, Hamburg (Germany); Hamburg Univ. (Germany); Navitski, Aliaksandr; Steder, Lea; Elsen, Eckhard [DESY, Hamburg (Germany)

    2013-07-01

    Superconducting radio-frequency (SRF) cavities are the key components of particle accelerators such as the European X-ray Free Electron Laser (XFEL, under construction) and the planned future International Linear Collider (ILC). Steady progress in surface treatment techniques of SRF cavities in both the achievable quality factor Q and the accelerating electric field Eacc makes new accelerators and ambitious projects feasible. One of the alternative surface preparation techniques which is actually being explored is centrifugal barrel polishing (CBP) pioneered at KEK in Japan in mid-nineties by T. Hiuchi et al. CBP is a mechanical polishing of cavities and results in around 10 x smaller surface roughness and mirror-like surface as compared to chemistry alone. Q and E{sub acc} are expected to be at least as high as for chemically treated cavities. CBP eliminates the bulk chemistry and has the potential to completely replace the chemistry. The University of Hamburg is installing a CBP machine to study it as a cavity preparation and repair technique for 9-cell 1.3 GHz SRF cavities at the Deutsche Elektronen-Synchrotron (DESY). The setup and first commissioning tests will be presented and discussed.

  4. A study on centrifugal casting of high speed steel roll

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    High speed steel (HSS) rolls can replace traditional rolls such as alloyed cast iron rolls and powder metallurgical (PM) hard alloy rolls. The main reasons for the replacement are that the wear resistance of low-cost alloyed cast iron rolls is poor and the cost of high-quality PM hard alloy rolls is very high. By means of centrifugal casting, HSS rolls having excellent wear resistance have been manufactured. The hardness of the HSS roll is 65~ 67 HRC, the range of variation is smaller than 2 HRC and its impact toughness is 15 J/cm2. The wear rate of HSS rolls used in the pre-finishing stands of high-speed hot wire-rod rolling mill reaches 2.5 × 10-4 mm per ton steel. Furthermore, the manufacturing cost of HSS rolls is significantly lower than that of PM hard alloy rolls; it is only 30 percent of that of PM hard alloy rolls.

  5. Optimal Design of a Centrifugal Compressor Impeller Using Evolutionary Algorithms

    Directory of Open Access Journals (Sweden)

    Soo-Yong Cho

    2012-01-01

    Full Text Available An optimization study was conducted on a centrifugal compressor. Eight design variables were chosen from the control points for the Bezier curves which widely influenced the geometric variation; four design variables were selected to optimize the flow passage between the hub and the shroud, and other four design variables were used to improve the performance of the impeller blade. As an optimization algorithm, an artificial neural network (ANN was adopted. Initially, the design of experiments was applied to set up the initial data space of the ANN, which was improved during the optimization process using a genetic algorithm. If a result of the ANN reached a higher level, that result was re-calculated by computational fluid dynamics (CFD and was applied to develop a new ANN. The prediction difference between the ANN and CFD was consequently less than 1% after the 6th generation. Using this optimization technique, the computational time for the optimization was greatly reduced and the accuracy of the optimization algorithm was increased. The efficiency was improved by 1.4% without losing the pressure ratio, and Pareto-optimal solutions of the efficiency versus the pressure ratio were obtained through the 21st generation.

  6. A study on centrifugal charaging pump shaft failure investigation

    Energy Technology Data Exchange (ETDEWEB)

    Jo, S. D.; Kim, B. K. [KEPCO, Woolsan (Korea, Republic of)

    2001-05-01

    Pump shafts in the centrifugal charging safety injection pumps in PWRs have been subject to occasional failures over the past several years. Service experience showed that the pump shaft failures can result in significant emergency repair and maintenance costs to the plant. Metallurgical investigations of the pump shafts fabricated prior to 1977 confirmed that the cracking was initiated at stress concentrations sitcs, such as a locknut thread root or a split ring groove, and progressed by a high cycle fatigue mechanism. Westinghouse implemented a series of improvements and upgrades to increase the safety margins and to mitigate the effect of the off-design operating conditions. These included design enhancements as well as material condition (heat treatment) modifications. The pump shaft upgrading program significantly improved the design life of the shafts but did not fully mitigate the issue. Investigation of recent failures of the upgraded shafts suggested that these failures are initiated by a combination of off-design loading events such as loss of flow or gas binding and a reduction of pump shaft resistance to cracking due to the aqueous environmental conditions.

  7. Fast Pyrolysis of Lignin Using a Pyrolysis Centrifuge Reactor

    DEFF Research Database (Denmark)

    Trinh, Ngoc Trung; Jensen, Peter Arendt; Sárossy, Zsuzsa

    2013-01-01

    Fast pyrolysis of lignin from an ethanol plant was investigated on a lab scale pyrolysis centrifuge reactor (PCR) with respect to pyrolysis temperature, reactor gas residence time, and feed rate. A maximal organic oil yield of 34 wt % dry basis (db) (bio-oil yield of 43 wt % db) is obtained...... at temperatures of 500−550 °C, reactor gas residence time of 0.8 s, and feed rate of 5.6 g/min. Gas chromatography mass spectrometry and size-exclusion chromatography were used to characterize the Chemical properties of the lignin oils. Acetic acid, levoglucosan, guaiacol, syringols, and p-vinylguaiacol are found...... to be major chemical components in the lignin oil. The maximal yields of 0.62, 0.67, and 0.38 wt % db were obtained for syringol, p-vinylguaiacol, and guaiacol, respectively. The reactor temperature effect was investigated in a range of 450−600 °C and has a considerable effect on the observed chemical...

  8. Autopsy findings in patients on postcardiotomy centrifugal ventricular assist.

    Science.gov (United States)

    Curtis, J J; Walls, J T; Boley, T M; Schmaltz, R A; Demmy, T L

    1992-01-01

    Reported experience with ventricular assist devices (VAD) routinely includes the rate of thromboembolic events, which is commonly calculated from clinically evident findings. Fifty-four patients have had postcardiotomy circulatory support with the Sarns centrifugal device at our institution. We have reviewed 43 patients who failed to survive VAD support to compare the thromboembolism rate diagnosed clinically to that determined at autopsy. In the 35 patients who had no autopsy, there was one clinically apparent thromboembolic event (2.3%). In eight similar patients who had autopsy, there was no clinically apparent thromboembolism. Five of these eight patients (63%) had acute thromboembolic infarcts determined at autopsy. Three had evidence of pulmonary thromboembolism, two cerebrovascular infarction, two liver infarcts, two splenic infarcts, two kidney infarcts, and one each gastric, pancreatic, prostate, adrenal, cervical, and ileal infarcts. All had left and/or right ventricular infarctions. It is concluded that patients dying following VAD have commonly suffered perioperative myocardial infarction. When evaluating complications associated with VAD, one should consider that the true incidence of thromboembolic events is underestimated by clinical findings.

  9. New approach for porous materials obtaining using centrifugal casting

    Science.gov (United States)

    Bălţătescu, O.; Axinte, M.; Barbu, G.; Manole, V.

    2015-11-01

    It has been presented different methods for obtaining porous materials, (mainly used for metallic foams) and highlighting a new technology developed in the Faculty of Materials science and engineering, of Iasi. Our technology for obtaining porous materials is called centrifugal casting for porous materials. This technology is included in the method number 8: co-pressing of a metal powder with a leachable powder being in the same time a newer approach in the porous materials field. This technology is currently in the developmental phase. Since now we made experiments on the metallic materials, aluminum alloys. The technology is briefly described in this paper. The obtained parts were used for making samples in order to characterize the properties of the materials. The cellular structure of metallic foams requires special precautions that must be taken in characterization and testing. In this paper we have characterized the samples structurally by its cell topology (open cells, closed cells), relative density, cell size and cell shape and anisotropy. Also it was used scanning electron microscopy (SEM) which is straightforward; the only necessary precaution is that relating to surface preparation.

  10. Casting behavior of titanium alloys in a centrifugal casting machine.

    Science.gov (United States)

    Watanabe, K; Miyakawa, O; Takada, Y; Okuno, O; Okabe, T

    2003-05-01

    Since dental casting requires replication of complex shapes with great accuracy, this study examined how well some commercial titanium alloys and experimental titanium-copper alloys filled a mold cavity. The metals examined were three types of commercial dental titanium [commercially pure titanium (hereinafter noted as CP-Ti), Ti-6Al-4V (T64) and Ti-6Al-7Nb (T67)], and experimental titanium-copper alloys [3%, 5% and 10% Cu (mass %)]. The volume percentage filling the cavity was evaluated in castings prepared in a very thin perforated sheet pattern and cast in a centrifugal casting machine. The flow behavior of the molten metal was also examined using a so-called "tracer element technique." The amounts of CP-Ti and all the Ti-Cu alloys filling the cavity were similar; less T64 and T67 filled the cavity. However, the Ti-Cu alloys failed to reach the end of the cavities due to a lower fluidity compared to the other metals. A mold prepared with specially designed perforated sheets was effective at differentiating the flow behavior of the metals tested. The present technique also revealed that the more viscous Ti-Cu alloys with a wide freezing range failed to sequentially flow to the end of the cavity.

  11. Central centrifugal cicatricial alopecia amalgamated with alopecia areata: immunologic findings

    Directory of Open Access Journals (Sweden)

    Ana Maria Abreu Velez

    2014-07-01

    Full Text Available Introduction: Both scarring and non-scarring alopecias exist; however, rare cases demonstrate features of both classes. Case Report: We describe an interesting alopecia case with amalgamated clinical, histologic and immunopathologic features of scarring and non-scarring alopecia. Specifically, the case displays combined features of alopecia areata (AA and of central centrifugal cicatricial alopecia (CCCA. A 36 year old female presented with symmetric, round, patchy hair loss on her scalp. Methods: Biopsies for hematoxylin and eosin (H&E examination, as well as for special stains, direct immunofluorescence (DIF and immunohistochemistry (IHC were performed. Results: The H&E biopsy revealed focally diminished hair follicular units, and sebaceous gland damage. Perifollicular concentric fibrosis was confirmed by Verhoeff elastin special staining. Antibodies to micelles were noted. Positive IHC staining for CD4, CD8, CD45 and multiple proteases and protease inhibitors was noted around selected follicular unit remnants. Conclusion: We present a rare alopecia, combining histologic features of CCCA with additional, selected immunologic features of AA.

  12. The computer simulation of 3d gas dynamics in a gas centrifuge

    Science.gov (United States)

    Borman, V. D.; Bogovalov, S. V.; Borisevich, V. D.; Tronin, I. V.; Tronin, V. N.

    2016-09-01

    We argue on the basis of the results of 2D analysis of the gas flow in gas centrifuges that a reliable calculation of the circulation of the gas and gas content in the gas centrifuge is possible only in frameworks of 3D numerical simulation of gas dynamics in the gas centrifuge (hereafter GC). The group from National research nuclear university, MEPhI, has created a computer code for 3D simulation of the gas flow in GC. The results of the computer simulations of the gas flows in GC are presented. A model Iguassu centrifuge is explored for the simulations. A nonaxisymmetric gas flow is produced due to interaction of the hypersonic rotating flow with the scoops for extraction of the product and waste flows from the GC. The scoops produce shock waves penetrating into a working camera of the GC and form spiral waves there.

  13. Centrifuge modeling of one-step outflow tests for unsaturated parameter estimations

    Directory of Open Access Journals (Sweden)

    H. Nakajima

    2006-05-01

    Full Text Available Centrifuge modeling of one-step outflow tests were carried out using a 2-m radius geotechnical centrifuge, and the cumulative outflow and transient pore pressure were measured during the tests at multiple gravity levels. Based on the scaling law of centrifuge modeling, the measurements generally showed reasonable agreement with prototype data calculated from forward simulations with input parameters determined from standard laboratory tests. The parameter optimizations were examined for three different combinations of input data sets using the test measurements. Within the gravity level examined in this study up to 40 g, the optimized unsaturated parameters compared well when accurate pore pressure measurements were included along with cumulative outflow as input data. The centrifuge modeling technique with its capability to implement variety of instrumentations under well controlled initial and boundary conditions, shortens testing time and can provide significant information for the parameter estimation procedure.

  14. [Pay attention to physical test and drafting product standards of the centrifuge apparatus].

    Science.gov (United States)

    Xu, Hui; Jia, Yufei; Li, Haixin; Song, Jinzi

    2010-03-01

    Compare and analyze the standards related to centrifuge apparatus and make corresponding suggestions in allusion to the problems existed in the test method and physical performance during product standard drafting process.

  15. Effect of Mould Wall Thickness on Rate of Solidification of Centrifugal Casting

    Directory of Open Access Journals (Sweden)

    Madhusudhan

    2010-11-01

    Full Text Available In Centrifugal Casting process the centrifugal force presses the metal against the inner wall of the metal mould, resulting in rapid solidification of the molten metal. However the solidification structures like structural uniformity and structural character of the solidified metal of centrifugal casting is of great importance, regarding to its mechanical properties. The solidification time of the casting is dependent upon the various parameters like speed ofrotation of the mold, mould wall temperature, heat transfer coefficient at the metal-mold interface, mould wall thickness, material of the mould and so on. In this paper experimental study of effect of mould wall thickness on solidification of the centrifugal casting has been discussed. As the mould wall thickness increases, due to the chilling effect, the solidification time decreases. Fine grains are observed in castings produced in thick walled mould and coarse grains are observed in thin walled moulds. Brinel Hardness of the casting was measured.

  16. COOLING METHOD OF SILUMINA CASTINGS AK15M3 AT VERTICAL CENTRIFUGAL CASTING

    Directory of Open Access Journals (Sweden)

    V. Yu. Stecenko

    2013-01-01

    Full Text Available The way of cooling of castings from silumin AK15M3 is developed at the vertical centrifugal casting, enabling to receive bimetallic blanks with high-disperse eutectic and hypereutectic microstructures and minimal allowance for machining.

  17. Numerical simulation for permanent mold centrifugal cast TiAl exhaust valve

    Institute of Scientific and Technical Information of China (English)

    SHENG Wen-bin; LI Dong

    2005-01-01

    The filling and solidification in centrifugal field, as well as the forming mechanism of off-center porosities were summarized, based on the mathematical model established for the centrifugal cast TiAl exhaust valves.The calculated results show that the centrifugal field results in the phenomenon that the flow in the valve cavity consists of forward flow and backward flow. The unsymmetrical initial temperature field causes continuous unsymmetrical variation in the following solidification, which makes the final solidified region depart from the cavity axis and then leads to the occurrence of off-center porosity. A series of optimized parameters, including the entrance velocity of 0.6 - 1.3 m/s, the rotation speed higher than 300 r/min, 80 mm or longer entrance length and 400 ℃ or higher preheated temperature of the mold, are suggested for the manufacture of permanent mold centrifugal cast TiAl exhaust valves.

  18. Filling and solidification of TiAl melt in centrifugal field

    Institute of Scientific and Technical Information of China (English)

    SHENG Wen-bin

    2006-01-01

    A model was established based on the combination of the equation of continuity,the equation of conservation of momentum and the equation of general energy to describe the filling and solidification of TiAl melt by permanent mold centrifugal casting. The model was solved numerically and the filling and solidification processes in the centrifugal field were discussed. The results indicate that the centrifugal field essentially influences the filling and solidification processes of TiAl melt. The melt will first fill the cavity along the back boundary until it reaches the end. After the end is fully filled,the whole cavity will be filled gradually by the way that free surface of the melt moves towards the entrance,hence the entrance is the last part to be filled. Furthermore,the mechanism by which internal defects can be formed in centrifugally cast TiAl components were interpreted.

  19. Nitrogen mineralization from anaerobically digested centrifuge cake and aged air-dried biosolids.

    Science.gov (United States)

    Kumar, Kuldip; Hundal, Lakhwinder S; Cox, Albert E; Granato, Thomas

    2014-09-01

    This study was conducted to estimate nitrogen (N) mineralization of anaerobically digested centrifuge cake from the Stickney Water Reclamation Plant (SWRP) and Calumet Water Reclamation Plant (CWRP), lagoon-aged air-dried biosolids from the CWRP, and Milorganite at three rates of application (0, 12.5 and 25 Mg ha(-1)). The N mineralized varied among biosolids as follows: Milorganite (44%) > SWRP centrifuge cake (35%) > CWRP centrifuge cake (31%) > aged air-dried (13%). The N mineralized in the SWRP cake (32%) and CWRP aged air-dried biosolids (12%) determined from the 15N study were in agreement with the first study. The N mineralization value for centrifuge cake biosolids observed in our study is higher than the value given in the Part 503 rule and Illinois Part 391 guidelines. These results will be used to fine-tune biosolids application rate to match crop N demand without compromising yield while minimizing any adverse effect on the environment.

  20. DESIGN AND DYNAMICAL SIMULATION TO NEW VIBRATING CENTRIFUGE WITH WIDER FREQUENCY RANGE

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A new type of vibrating centrifuge with wider frequency range is designed instead of the traditional one with a single frequency to improve the vibrating effect. With the aid of a new dynamical model, one simulation without considering the visco-elasticity of basis is presented, then the dynamical responses of time and frequency in different scheme are given. The computational results show that the improved vibrating centrifuge possesses a remarkably widened frequency range.

  1. Flow Field of Metallic Fluid Acted by Electromagnetic and Centrifugal Force

    Institute of Scientific and Technical Information of China (English)

    QIU Yi-qing; LUO Zong-an; JIA Guang-lin; LIU Xiang-hua; WANG Guo-dong

    2004-01-01

    According to the principle of electromagnetism and hydrodynamics, a mathematical model of flow field for metallic fluid acted by electromagnetic and centrifugal forces was established. The calculation results showed that the relative velocity between metallic fluid layers rises and the absolute rotational velocity of metallic fluid falls with the increase of magnetic induction intensity. The increase of centrifugal revolution hardly affects the relative velocity between metallic fluid layers, but can enhance the absolute rotational velocity of metallic fluid.

  2. Modeling on Fluid Flow and Inclusion Motion in Centrifugal Continuous Casting Strands

    Science.gov (United States)

    Wang, Qiangqiang; Zhang, Lifeng; Sridhar, Seetharaman

    2016-08-01

    During the centrifugal continuous casting process, unreasonable casting parameters can cause violent level fluctuation, serious gas entrainment, and formation of frozen shell pieces at the meniscus. Thus, in the current study, a three-dimensional multiphase turbulent model was established to study the transport phenomena during centrifugal continuous casting process. The effects of nozzle position, casting and rotational speed on the flow pattern, centrifugal force acting on the molten steel, level fluctuation, gas entrainment, shear stress on mold wall, and motion of inclusions during centrifugal continuous casting process were investigated. Volume of Fluid model was used to simulate the molten steel-air two-phase. The level fluctuation and the gas entrainment during casting were calculated by user-developed subroutines. The trajectory of inclusions in the rotating system was calculated using the Lagrangian approach. The results show that during centrifugal continuous casting, a large amount of gas was entrained into the molten steel, and broken into bubbles of various sizes. The greater the distance to the mold wall, the smaller the centrifugal force. Rotation speed had the most important influence on the centrifugal force distribution at the side region. Angular moving angle of the nozzle with 8° and keeping the rotation speed with 60 revolutions per minute can somehow stabilize the level fluctuation. The increase of angular angle of nozzle from 8 to 18 deg and rotation speed from 40 to 80 revolutions per minute favored to decrease the total volume of entrained bubbles, while the increase of distance of nozzle moving left and casting speed had reverse effects. The trajectories of inclusions in the mold were irregular, and then rotated along the strand length. After penetrating a certain distance, the inclusions gradually moved to the center of billet and gathered there. More work, such as the heat transfer, the solidification, and the inclusions entrapment

  3. Comparison of centrifuged liquid based cytology method with conventional brush cytology in oral lesions

    OpenAIRE

    Nidhi Dwivedi; Akhil Agarwal; Vineet Raj; Bina Kashyap; Shaleen Chandra

    2012-01-01

    Background: Exfoliative cytology is the study of cells that are shed or scrapped off from mucosal surfaces. Centrifuged Liquid based cytology is a modified technique employed in the present study. Aims: To compare the utility of centrifuged liquid based cytology with conventional cytology in oral lesions after staining with Papanicolaou (PAP) stain. Materials and Methods: 50 cases of oral lesions comprising of normal mucosa (n=14), hyperkeratotic lesions (n=17), ulcerated lesions (n=7) and at...

  4. Continuous size-based separation of microparticles in a microchannel with symmetric sharp corner structures.

    Science.gov (United States)

    Fan, Liang-Liang; He, Xu-Kun; Han, Yu; Du, Li; Zhao, Liang; Zhe, Jiang

    2014-03-01

    A new microchannel with a series of symmetric sharp corner structures is reported for passive size-dependent particle separation. Micro particles of different sizes can be completely separated based on the combination of the inertial lift force and the centrifugal force induced by the sharp corner structures in the microchannel. At appropriate flow rate and Reynolds number, the centrifugal force effect on large particles, induced by the sharp corner structures, is stronger than that on small particles; hence after passing a series of symmetric sharp corner structures, large particles are focused to the center of the microchannel, while small particles are focused at two particle streams near the two side walls of the microchannel. Particles of different sizes can then be completely separated. Particle separation with this device was demonstrated using 7.32 μm and 15.5 μm micro particles. Experiments show that in comparison with the prior multi-orifice flow fractionation microchannel and multistage-multiorifice flow fractionation microchannel, this device can completely separate two-size particles with narrower particle stream band and larger separation distance between particle streams. In addition, it requires no sheath flow and complex multi-stage separation structures, avoiding the dilution of analyte sample and complex operations. The device has potentials to be used for continuous, complete particle separation in a variety of lab-on-a-chip and biomedical applications.

  5. Ionene membrane battery separator

    Science.gov (United States)

    Moacanin, J.; Tom, H. Y.

    1969-01-01

    Ionic transport characteristics of ionenes, insoluble membranes from soluble polyelectrolyte compositions, are studied for possible application in a battery separator. Effectiveness of the thin film of separator membrane essentially determines battery lifetime.

  6. Separation anxiety in children

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/001542.htm Separation anxiety in children To use the sharing features on this page, please enable JavaScript. Separation anxiety in children is a developmental stage in which ...

  7. Magnetic separation of algae

    Energy Technology Data Exchange (ETDEWEB)

    Nath, Pulak; Twary, Scott N.

    2016-04-26

    Described herein are methods and systems for harvesting, collecting, separating and/or dewatering algae using iron based salts combined with a magnetic field gradient to separate algae from an aqueous solution.

  8. Asparaginase-associated concurrence of hyperlipidemia, hyperglobulinemia, and thrombocytosis was successfully treated by centrifuge/membrane hybrid double-filtration plasmapheresis.

    Science.gov (United States)

    Wang, Taina; Xu, Bin; Fan, Rong; Liu, Zhihong; Gong, Dehua

    2016-01-01

    Asparaginase-associated concurrence of hyperlipidemia, hyperglobulinemia, and thrombocytosis is a rare complication requiring aggressive lipoprotein apheresis, but no one of currently available lipoprotein apheresis methods can simultaneously resolve the 3 abnormalities. Herein, we reported a construction of double-filtration plasmapheresis (DFPP) using a combination of centrifugal/membranous plasma separation techniques to successfully treat a patient with hyperlipidemia, hyperglobulinemia, and thrombocytosis. A male presented with severe hyperlipidemia, hyperglobulinemia, and thrombocytosis during asparaginase treatment for NK/T-cell lymphoblastic lymphoma and was scheduled to receive lipoprotein apheresis. To simultaneously remove lipoproteins, immunoglobulin, and deplete platelets from blood, a centrifuge/membrane hybrid DFPP was constructed as following steps: plasma and part of platelets were separated first from whole blood by centrifugal technique and then divided by a fraction plasma separator into 2 parts: platelets and plasma components with large size, which were discarded; and those containing albumin, which were returned to blood with a supplement of extrinsic albumin solution. DFPP lasted 240 minutes uneventfully, processing 5450-mL plasma. The concentrations of plasma components before DFPP were as follows: triglycerides 38.22 mmol/L, total cholesterols 22.98 mmol/L, immunoglobulin A (IgA) 15.7 g/L, IgG 12.7 g/L, and IgM 14.3 g/L; whereas after treatment were 5.69 mmol/L, 2.38 mmol/L, 2.5 g/L, 7.7 g/L, and 0.4 g/L, respectively. The respective reduction ratio was 85.1%, 89.6%, 83.9%, 39.4%, and 96.9%. Platelet count decreased by 40.4% (from 612 × 10(9)/L to 365 × 10(9)/L). Centrifuge/membrane hybrid DFPP can simultaneously remove lipoproteins, immunoglobulin, and deplete platelets, with a success in treatment of asparaginase treatment-induced hyperlipidemia, hyperglobulinemia, and thrombocytosis, and may be useful for patients

  9. New methods and media for the centrifugation of honey bee (Hymenoptera: Apidae) drone semen.

    Science.gov (United States)

    Wegener, Jakob; May, Tanja; Kamp, Günter; Bienefeld, Kaspar

    2014-02-01

    Centrifugation of Apis mellifera L. drone semen is a necessary step in the homogenization of semen pools for the enlargement of the effective breeding population, as well as in the collection of semen by the so-called washing technique. It is also of interest for the removal of cryoprotectants after cryopreservation. The adoption of methods involving semen centrifugation has been hampered by their damaging effect to sperm. Here, we tested four new diluents as well as three additives (catalase, hen egg yolk, and a protease inhibitor), using sperm motility and dual fluorescent staining as indicators of semen quality. Three of the new diluents significantly reduced motility losses after centrifugation, as compared with the literature standard. Values of motility and propidium iodide negativity obtained with two of these diluents were not different from those measured with untreated semen. The least damaging diluent, a citrate-HEPES buffer containing trehalose, was then tested in an insemination experiment with centrifuged semen. Most queens receiving this semen produced normal brood, and the number of sperm reaching the storage organ of the queen was not significantly different from that in queens receiving untreated semen. These results could improve the acceptance of techniques involving the centrifugation of drone semen. The diluent used in the insemination experiment could also serve as semen extender for applications not involving centrifugation.

  10. Active pneumatic control of centrifugal microfluidic flows for lab-on-a-chip applications.

    Science.gov (United States)

    Clime, Liviu; Brassard, Daniel; Geissler, Matthias; Veres, Teodor

    2015-06-01

    This paper reports a novel method of controlling liquid motion on a centrifugal microfluidic platform based on the integration of a regulated pressure pump and a programmable electromechanical valving system. We demonstrate accurate control over the displacement of liquids within the system by pressurizing simultaneously multiple ports of the microfluidic device while the platform is rotating at high speed. Compared to classical centrifugal microfluidic platforms where liquids are solely driven by centrifugal and capillary forces, the method presented herein adds a new degree of freedom for fluidic manipulation, which represents a paradigm change in centrifugal microfluidics. We first demonstrate how various core microfluidic functions such as valving, switching, and reverse pumping (i.e., against the centrifugal field) can be easily achieved by programming the pressures applied at dedicated access ports of the microfluidic device. We then show, for the first time, that the combination of centrifugal force and active pneumatic pumping offers the possibility of mixing fluids rapidly (~0.1 s) and efficiently based on the creation of air bubbles at the bottom of a microfluidic reservoir. Finally, the suitability of the developed platform for performing complex bioanalytical assays in an automated fashion is demonstrated in a DNA harvesting experiment where recovery rates of about 70% were systematically achieved. The proposed concept offers the interesting prospect to decouple basic microfluidic functions from specific material properties, channel dimensions and fabrication tolerances, surface treatments, or on-chip active components, thus promoting integration of complex assays on simple and low-cost microfluidic cartridges.

  11. The Effect of Moment of Inertia on the Liquids in Centrifugal Microfluidics

    Directory of Open Access Journals (Sweden)

    Esmail Pishbin

    2016-12-01

    Full Text Available The flow of liquids in centrifugal microfluidics is unidirectional and dominated by centrifugal and Coriolis forces (i.e., effective only at T-junctions. Developing mechanisms and discovering efficient techniques to propel liquids in any direction other than the direction of the centrifugal force has been the subject of a large number of studies. The capillary force attained by specific surface treatments, pneumatic energy, active and passive flow reciprocation and Euler force have been previously introduced in order to manipulate the liquid flow and push it against the centrifugal force. Here, as a new method, the moment of inertia of the liquid inside a chamber in a centrifugal microfluidic platform is employed to manipulate the flow and propel the liquid passively towards the disc center. Furthermore, the effect of the moment of inertia on the liquid in a rectangular chamber is evaluated, both in theory and experiments, and the optimum geometry is defined. As an application of the introduced method, the moment of inertia of the liquid is used in order to mix two different dyed deionized (DI waters; the mixing efficiency is evaluated and compared to similar mixing techniques. The results show the potential of the presented method for pumping liquids radially inward with relatively high flow rates (up to 23 mm3/s and also efficient mixing in centrifugal microfluidic platforms.

  12. Feasibility of a Short-Arm Centrifuge for Mouse Hypergravity Experiments

    Science.gov (United States)

    Morita, Hironobu; Obata, Koji; Abe, Chikara; Shiba, Dai; Shirakawa, Masaki; Kudo, Takashi; Takahashi, Satoru

    2015-01-01

    To elucidate the pure impact of microgravity on small mammals despite uncontrolled factors that exist in the International Space Station, it is necessary to construct a 1 g environment in space. The Japan Aerospace Exploration Agency has developed a novel mouse habitat cage unit that can be installed in the Cell Biology Experiment Facility in the Kibo module of the International Space Station. The Cell Biology Experiment Facility has a short-arm centrifuge to produce artificial 1 g gravity in space for mouse experiments. However, the gravitational gradient formed inside the rearing cage is larger when the radius of gyration is shorter; this may have some impact on mice. Accordingly, biological responses to hypergravity induced by a short-arm centrifuge were examined and compared with those induced by a long-arm centrifuge. Hypergravity induced a significant Fos expression in the central nervous system, a suppression of body mass growth, an acute and transient reduction in food intake, and impaired vestibulomotor coordination. There was no difference in these responses between mice raised in a short-arm centrifuge and those in a long-arm centrifuge. These results demonstrate the feasibility of using a short-arm centrifuge for mouse experiments. PMID:26221724

  13. Feasibility of a Short-Arm Centrifuge for Mouse Hypergravity Experiments.

    Directory of Open Access Journals (Sweden)

    Hironobu Morita

    Full Text Available To elucidate the pure impact of microgravity on small mammals despite uncontrolled factors that exist in the International Space Station, it is necessary to construct a 1 g environment in space. The Japan Aerospace Exploration Agency has developed a novel mouse habitat cage unit that can be installed in the Cell Biology Experiment Facility in the Kibo module of the International Space Station. The Cell Biology Experiment Facility has a short-arm centrifuge to produce artificial 1 g gravity in space for mouse experiments. However, the gravitational gradient formed inside the rearing cage is larger when the radius of gyration is shorter; this may have some impact on mice. Accordingly, biological responses to hypergravity induced by a short-arm centrifuge were examined and compared with those induced by a long-arm centrifuge. Hypergravity induced a significant Fos expression in the central nervous system, a suppression of body mass growth, an acute and transient reduction in food intake, and impaired vestibulomotor coordination. There was no difference in these responses between mice raised in a short-arm centrifuge and those in a long-arm centrifuge. These results demonstrate the feasibility of using a short-arm centrifuge for mouse experiments.

  14. Roller and Centrifugal Pumps: A Retrospective Comparison of Bleeding Complications in Extracorporeal Membrane Oxygenation.

    Science.gov (United States)

    Halaweish, Ihab; Cole, Adam; Cooley, Elaine; Lynch, William R; Haft, Jonathan W

    2015-01-01

    Centrifugal pumps are increasingly used for extracorporeal membrane oxygenation (ECMO) rather than roller pumps. However, shear forces induced by these types of continuousflow pumps are associated with acquired von Willebrand factor deficiency and bleeding complications. This study was undertaken to compare adverse bleeding complications with the use of centrifugal and roller pumps in patients on prolonged ECMO support. The records of all adult ECMO patients from June 2002 to 2013 were retrospectively reviewed using the University of Michigan Health System database and the Extracorporeal Life Support Organization registry, focusing on patients supported for at least 5 days. Ninety-five ECMO patients met criteria for inclusion (48 roller vs. 47 centrifugal pump). Indications included pulmonary (79%), cardiac (15%), and extracorporeal cardiopulmonary resuscitation (6%), without significant difference between the two groups. Despite lower heparin anticoagulation (10.9 vs. 13.7 IU/kg/hr) with centrifugal pumps, there was a higher incidence of nonsurgical bleeding (gastrointestinal, pulmonary, and neurological) in centrifugal pump patients (26.1 vs. 9.0 events/1,000 patient-days, p = 0.024). In conclusion, in our historical comparison, despite reduced anticoagulation, ECMO support using centrifugal pumps was associated with a higher incidence of nonsurgical bleeding. The mechanisms behind this are multifactorial and require further investigation.

  15. 离心静电纺丝的模式%Modes of Centrifugal Electrospinning

    Institute of Scientific and Technical Information of China (English)

    彭浩; 张敬男; 李秀红; 宋庆松; 刘勇

    2015-01-01

    The mechanism and characteristics of centrifugal electrospinning were introduced. According to the different spinning materials,the centrifugal electrospinning was devided into solution centrifugal electrospinning and melt centrifugal electrospinning. The devices of the two type centrifugal electrospinning were divided into two types:conventional mode and revised mode. The structural characteristics,the advantages and disadvantages of all kinds of devices were summarized. The problems of the centrifugal electrospinning were pointed out and some advices for improvement were proposed.%介绍了离心静电纺丝的原理及特点,根据纺丝介质的不同,将离心静电纺丝分为溶液离心静电纺丝和熔体离心静电纺丝两类,并将这两类纺丝方法的装置分为常规模式和改进模式,总结了各种装置的结构特征、纺丝的优缺点。指出了现阶段离心静电纺丝存在的一些问题,并提出了相应的改进方案。

  16. Theoretical and Experimental Investigations into Centrifugal Desalting of Sea Ice%海冰离心脱盐理论与实验研究

    Institute of Scientific and Technical Information of China (English)

    谭蔚; 李春亮; 高晓冲; 贾占斌

    2011-01-01

    海冰盐度主要来自海水结冰时被包裹在内部的卤水盐胞,海冰离心脱盐方法正是依据此,将海冰破碎,使卤水暴露出来,进而施加超重力,脱除卤水,淡化海冰.本文通过理论分析得出海冰离心脱盐后盐度与时间的理论关系式为S(t)=PK√1/t万,采用该式的计算结果与文献中的实验数据对比表明两者吻合较好.在理论分析基础上,通过实验确定了粒度、分离因数和加入海水比例对海冰离心脱盐的影响.实验结果表明,淡化盐度随着粒径呈现先减小后增大的趋势,并且当颗粒在6~9mm左右达到最小;随着加入海水比例和分离因数的增大,海冰离心脱盐效果变好.%Salinity of sea ice results mainly from brine salinity cell wrapped inside when sea ice is freezing. In terms of this, methods of centrifugal separation of sea ice are suggested as follows: 1) breaking the ice so that salt brine is exposed and 2) using the large gravity of ice to remove sea brine and dilution sea ice by centrifuge. Through a theoretical analysis, a mathematical formula depicting the relationship between the salinity and the time after centrifugal desalting of sea ice,S(t) = PK √1/t where P is a correction factor was derived. It shows good agreement with results from other studies when taking the correction factor P to be 82. From the proposed formula, it can be seen that there exists a power functional relationship between the diluted salinity and the factors,i.e., time, separation factor, and liquid viscosity K. The diluted process of salinity is mainly completed in several seconds. With time increasing, salinity will be steady. The diluted salinity decreases with an increase in the separation factor and stabilizes at some separation factor value.With lower viscosity and lower salinity, the diluting brine can be more efficient. This suggests that adding water would be a good way to dilute salinity because of diluting brine and decreasing viscosity

  17. Appropriate Separator Sizing: A Modified Stewart and Arnold Method

    Directory of Open Access Journals (Sweden)

    F. Boukadi

    2012-01-01

    Full Text Available Oil and gas separators were one of the first pieces of production equipment to be used in the petroleum industry. The different stages of separation are completed using the following three principles: gravity, centrifugal force, and impingement. The sizes of the oil droplets, in the production water, are based mainly on the choke valve pressure drop. The choke valve pressure drop creates a shearing effect; this reduces the ability of the droplets to combine. One of the goals of oil separation is to reduce the shearing effect of the choke. Separators are conventionally designed based on initial flow rates; as a result, the separator is no longer able to accommodate totality of produced fluids. Changing fluid flow rates as well as emulsion viscosity effect separator design. The reduction in vessel performance results in recorded measurements that do not match actual production levels inducing doubt into any history matching process and distorting reservoir management programs. In this paper, the new model takes into account flow rates and emulsion viscosity. The generated vessel length, vessel diameter, and slenderness ratio monographs are used to select appropriate separator size based on required retention time. Model results are compared to API 12J standards.

  18. PIV pictures of stream field predict haemolysis index of centrifugal pump with streamlined impeller.

    Science.gov (United States)

    Qian, K X; Feng, Z G; Ru, W M; Zeng, P; Yuan, H Y

    2007-01-01

    Previously it has been found by pump haemolysis testing that the flow rate has a remarkable effect on index of haemolysis (IH), while pressure head does not affect IH. Recent investigation with particle image velocimetry (PIV) technology has demonstrated that IH is directly related to the flow pattern of stream field in impeller vane channels. PIV is a visible approach showing the real flow status in the pump. The different positions of a tracer particle in two PIV pictures taken at 20 micros intervals decide the velocity value and direction. The velocity vectors of many particles draw the flow pattern of the stream field. The same pictures are taken at 2, 4 and 6 l min(-1) flow rates while the pressure head is kept unchanged at 100 mmHg; then the pictures are taken at 4 l min(-1) flow with different pressure heads of 80, 100 and 120 mmHg. Results reveal that the flow rate of 4 l min(-1) (IH = 0.030) has the best stream field, and neither turbulence nor separation can be seen. In other flow rates (IH: 0.048 - 0.082), there is obviously second flow. Meanwhile, no significant difference can be seen among the PIV pictures of different pressure heads pumped, which agrees with the results of haemolysis testing showing that pressure has no effect on pump haemolysis. It may be concluded that the haemolysis property of a centrifugal pump can be assessed approximately by PIV pictures, which are much easier to take than haemolysis tests.

  19. A Comparison of delO18 Composition of Water Extracted from Suction Lysimeters, Centrifugation, and Azeotropic Distillation

    Science.gov (United States)

    Figueroa, A.; Tindall, J. A.; Friedel, M. J.

    2005-12-01

    variable. The data also suggest that each extraction method samples a separate component of soil-pore water. Consequently, centrifugation can be used with good success, particularly for efficient sampling of large areas. Azeotropic distillation is more appropriate when strict qualitative and quantitative data for desorption, desorption, and various types of kinetic studies are needed.

  20. Defining the needs for gas centrifuge enrichment plants advanced safeguards

    Energy Technology Data Exchange (ETDEWEB)

    Boyer, Brian David [Los Alamos National Laboratory; Erpenbeck, Heather H [Los Alamos National Laboratory; Miller, Karen A [Los Alamos National Laboratory; Swinhoe, Martyn T [Los Alamos National Laboratory; Ianakiev, Kiril [Los Alamos National Laboratory; Marlow, Johnna B [Los Alamos National Laboratory

    2010-04-05

    Current safeguards approaches used by the International Atomic Energy Agency (IAEA) at gas centrifuge enrichment plants (GCEPs) need enhancement in order to verify declared low-enriched (LEU) production, detect undeclared LEU production and detect highly enriched uranium (HEU) production with adequate detection probability using nondestructive assay (NDA) techniques. At present inspectors use attended systems, systems needing the presence of an inspector for operation, during inspections to verify the mass and {sup 235}U enrichment of declared UF{sub 6} containers used in the process of enrichment at GCEPs. In verifying declared LEU production, the inspectors also take samples for off-site destructive assay (DA) which provide accurate data, with 0.1% to 0.5% measurement uncertainty, on the enrichment of the UF{sub 6} feed, tails, and product. However, taking samples of UF{sub 6} for off-site analysis is a much more labor and resource intensive exercise for the operator and inspector. Furthermore, the operator must ship the samples off-site to the IAEA laboratory which delays the timeliness of results and interruptions to the continuity of knowledge (CofK) of the samples during their storage and transit. This paper contains an analysis of possible improvements in unattended and attended NDA systems such as process monitoring and possible on-site analysis of DA samples that could reduce the uncertainty of the inspector's measurements and provide more effective and efficient IAEA GCEPs safeguards. We also introduce examples advanced safeguards systems that could be assembled for unattended operation.

  1. Development of centrifugal casting high speed steel rolls

    Institute of Scientific and Technical Information of China (English)

    Hanguang Fu; Aimin Zhao; Jiandong Xing

    2003-01-01

    The present study aims at developing the high speed steel (HSS) as roll materials to replace the traditional roll materials such as the alloy cast iron and powder metallurgical (PM) hard alloy. The HSS roll billet was formed by centrifugal casting, and the billet was rough machined after soften annealing heat treatment, then it was quenched and tempered to get suitable hardness and toughness. After that the HSS roll was finish machined to the final dimension of φ285 mm in the outer diameter, φ160 mm in the inner diameter and 120 mm in width and its surface hardness was tested. Finally the HSS roll was used in high speed wire rod mill. The test results show that a high and homogeneous hardness can obtain on the work surface of HSS rolls, the surface hardness is 63-65HRC and its variation is smaller than 2HRC. The impact toughness of this kind of HSS is about 16 J/cra2. The results of on-line service investigation in high speed wire rod mill indicate that the HSS rolls have excellent wear resistance, the steel rolling quantity per mm of HSS rolls is 3120 t, the service life-span of HSS rolls is 4 times longer than that of high chromium cast iron rolls and it is close to that of the PM hard alloy rolls. The manufacturing burden of HSS rolls is obviously lower than that of the PM hard alloy rolls, it is only 25% of that of the PM hard alloy rolls.

  2. Direct digital manufacturing of autonomous centrifugal microfluidic device

    Science.gov (United States)

    Ukita, Yoshiaki; Takamura, Yuzuru; Utsumi, Yuichi

    2016-06-01

    This paper presents strategies that attempt to solve two key problems facing the commercialization of microfluidics: cost reduction in microfluidic chip manufacturing and microfluidic device driver development. To reduce the cost of microfluidic chip manufacturing, we propose to use of three-dimensional (3D) printers for direct digital manufacturing (DDM). An evaluation of 3D micro-scale structure printing using several 3D printers is reported, and some of the technical issues to be addressed in the future are suggested. To evaluate micro-scale printing, three types of 3D printers, with the ability to print structures on the scale of several hundred meters, were selected by first screening six 3D printers. Line and space patterns with line widths of 100-500 µm and an aspect ratio of one were printed and evaluated. The estimated critical dimension was around 200 µm. The manufacturing of a monolithic microfluidic chip with embedded channels was also demonstrated. Monolithic microfluidic chips with embedded microchannels having 500 × 500 and 250 × 250 µm2 cross sections and 2-20 mm lengths were printed, and the fidelity of the channel shape, residual supporting material, and flow of liquid water were evaluated. The liquid flow evaluation showed that liquid water could flow through all of the microchannels with the 500 × 500 µm2 cross section, whereas this was not possible through some of the channels with the 250 × 250 µm2 cross section because of the residual resin or supporting material. To reduce the device-driver cost, we propose to use of the centrifugal microfluidic concept. An autonomous microfluidic device that could implement sequential flow control under a steadily rotating condition was printed. Four-step flow injection under a steadily rotating condition at 1500 rpm was successfully demonstrated without any external triggering such as changing the rotational speed.

  3. Separation, fractionation, concentration and drying of food products: Final report, March 4, 1987--March 31, 1988

    Energy Technology Data Exchange (ETDEWEB)

    Merlo, C.A.; Rose, W.W.; Pedersen, L.D.; Brewbaker, P.L.

    1988-03-01

    This project studied energy efficient processes for separation, fractionation, concentration, drying, and recombination of food products, in order to reduce energy requirements for processing, preservation, and transportation. The project had three phases. In the laboratory-scale phase, results of which are summarized in this report, tomato puree was separated by three methods: conventional vacuum filtration, centrifugation, and crossflow microfiltration to produce pulp and serum. Three methods of recombination were examined: homogenizing, stomacher blending, and static (in-line) mixing. Satisfactory recombined purees were obtained. In addition, after centrifugation, the pulp was rinsed producing rinsed-pulp, and the rinse water was added to the serum producing rinse/serum. The rinse/serum was concentrated by evaporation. This was recombined with the rinsed-pulp and water producing satisfactory puree. 11 refs., 18 figs., 18 tabs.

  4. Anaerobic digestion of pig manure fibres from commercial pig slurry separation units

    DEFF Research Database (Denmark)

    Thygesen, Ole; Triolo, Jin M.; Sommer, Sven G.

    2014-01-01

    The composition of manure fibres (MF) from 17 commercially separated pig slurries and seven raw pig slurries were characterised in terms of dry matter (DM), volatile solids (VS), protein, hemicellulose, cellulose and lignin. The average lignocellulose concentration in manure fibres and pig slurries...... was 790 and 370gkg-1 [VS] respectively. Biochemical methane potential was ascertained after 60 days, revealing a trend in biochemical methane potential between the different separation technologies used: pig slurry>shaking filter and screw press combined≈decanter centrifuge>flocculation, belt and screw...... press combined≈screw press. The maximum methane yield of manure fibres from decanter centrifuges and the combined shaking filter and screw press was approximately 330l [CH4]kg-1 [VS] at standard temperature and pressure (STP), while manure fibres from a screw press and a combination of belt press...

  5. Engineering evaluation of solids/liquids separation processes applicable to sludge treatment project

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, J.B.

    1998-08-25

    This engineering study looks at the solids/liquids separation unit operations after the acid dissolution of the K Basin sludge treatment. Unit operations considered were centrifugation, filtration (cartridge, cross flow, and high shear filtration) and gravity settling. The recommended unit operations for the solids/liquids separations are based upon the efficiency, complexity, and off-the-shelf availability and adaptability. The unit operations recommended were a Robatel DPC 900 centrifuge followed by a nuclearized 31WM cartridge filter. The Robatel DPC 900 has been successfully employed in the nuclear industry on a world wide scale. The 31WM cartridge filter has been employed for filtration campaigns in both the government and civilian nuclear arenas.

  6. Neuro-Motor Responses to Daily Centrifugation in Bed-Rested Subjects

    Science.gov (United States)

    Reschke, Millard F.; Somers, Jeffery T.; Krnavek, Jody; Fisher, Elizibeth; Ford, George; Paloski, William H.

    2007-01-01

    It is well known from numerous space flight studies that exposure to micro-g produces both morphological and neural adaptations in the major postural muscles. However, the characteristics and mechanism of these changes, particularly when it may involve the central nervous system are not defined. Furthermore, it is not known what role unloading of the muscular system may have on central changes in sensorimotor function or if centrifugation along the +Gz direction (long body axis) can mitigate both the peripheral changes in muscle function and modification of the central changes in sensorimotor adaptation to the near weightless environment of space flight. The purpose of this specific effort was, therefore, to investigate the efficacy of artificial gravity (AG) as a method for maintaining sensorimotor function in micro-g. Eight male subjects were exposed to daily 1 hr centrifugation during a 21 day 6 degree head-down bed rest study. Seven controls were placed on the centrifuge without rotation. The radius and angular velocity of the centrifuge were adjusted such that each subject experienced a centripetal acceleration of 2.5g at the feet, and approximately 1.0g at the heart. Both the tendon (MSR) and functional stretch reflexes (FSR) were collected using an 80 lb. ft. servomotor controlled via position feedback to provide a dorsiflexion step input to elicit the MSR, and the same step input with a built in 3 sec hold to evoke the FSR. EMG data were obtained from the triceps surae. Supplementary torque, velocity and position data were collected with the EMG responses. All data were digitized and sampled at 4 kHz. Only the MSR data has been analyzed at this time, and preliminary results suggest that those subjects exposed to active centrifugation (treatment group) show only minor changes in MSR peak latency times, either as a function of time spent in bed rest or exposure to centrifugation, while the control subjects show delays in the MSR peak latencies that are

  7. Rapid chemical separations

    CERN Document Server

    Trautmann, N

    1976-01-01

    A survey is given on the progress of fast chemical separation procedures during the last few years. Fast, discontinuous separation techniques are illustrated by a procedure for niobium. The use of such techniques for the chemical characterization of the heaviest known elements is described. Other rapid separation methods from aqueous solutions are summarized. The application of the high speed liquid chromatography to the separation of chemically similar elements is outlined. The use of the gas jet recoil transport method for nuclear reaction products and its combination with a continuous solvent extraction technique and with a thermochromatographic separation is presented. Different separation methods in the gas phase are briefly discussed and the attachment of a thermochromatographic technique to an on-line mass separator is shown. (45 refs).

  8. Acoustofluidic bacteria separation

    Science.gov (United States)

    Li, Sixing; Ma, Fen; Bachman, Hunter; Cameron, Craig E.; Zeng, Xiangqun; Huang, Tony Jun

    2017-01-01

    Bacterial separation from human blood samples can help with the identification of pathogenic bacteria for sepsis diagnosis. In this work, we report an acoustofluidic device for label-free bacterial separation from human blood samples. In particular, we exploit the acoustic radiation force generated from a tilted-angle standing surface acoustic wave (taSSAW) field to separate Escherichia coli from human blood cells based on their size difference. Flow cytometry analysis of the E. coli separated from red blood cells shows a purity of more than 96%. Moreover, the label-free electrochemical detection of the separated E. coli displays reduced non-specific signals due to the removal of blood cells. Our acoustofluidic bacterial separation platform has advantages such as label-free separation, high biocompatibility, flexibility, low cost, miniaturization, automation, and ease of in-line integration. The platform can be incorporated with an on-chip sensor to realize a point-of-care sepsis diagnostic device.

  9. Combining ergometer exercise and artificial gravity in a compact-radius centrifuge

    Science.gov (United States)

    Diaz, Ana; Trigg, Chris; Young, Laurence R.

    2015-08-01

    Humans experience physiological deconditioning during space missions, primarily attributable to weightlessness. Some of these adverse consequences include bone loss, muscle atrophy, sensory-motor deconditioning, and cardiovascular alteration, which may lead to orthostatic intolerance when astronauts return to Earth. Artificial gravity could provide a comprehensive countermeasure capable of challenging all the physiological systems at once, particularly if combined with exercise, thereby maintaining overall health during extended exposure to weightlessness. A new Compact Radius Centrifuge (CRC) platform was designed and built on the existing Short Radius Centrifuge (SRC) at the Massachusetts Institute of Technology (MIT). The centrifuge has been constrained to a radius of 1.4 m, the upper radial limit for a centrifuge to fit within an International Space Station (ISS) module without extensive structural alterations. In addition, a cycle ergometer has been added for exercise during centrifugation. The CRC now includes sensors of foot forces, cardiovascular parameters, and leg muscle electromyography. An initial human experiment was conducted on 12 subjects to analyze the effects of different artificial gravity levels (0 g, 1 g, and 1.4 g, measured at the feet) and ergometer exercise intensities (25 W warm-up, 50 W moderate and 100 W vigorous) on the musculoskeletal function as well as motion sickness and comfort. Foot forces were measured during the centrifuge runs, and subjective comfort and motion sickness data were gathered after each session. Preliminary results indicate that ergometer exercise on a centrifuge may be effective in improving musculoskeletal function. The combination is well tolerated and motion sickness is minimal. The MIT CRC is a novel platform for future studies of exercise combined with artificial gravity. This combination may be effective as a countermeasure to space physiological deconditioning.

  10. Wet counter flow microfine classification in a centrifuge

    Energy Technology Data Exchange (ETDEWEB)

    Timmermann, D.; Schoenert, K. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). Inst. fuer Aufbereitung von Rohstoffen und Reststoffen

    1995-12-31

    This paper reports on the results of research on counter flow classification of {minus}10 {micro}m particles.Two classifiers were designed and constructed, the first semicontinuous and the second fully continuous. The latest version operates continuously with recoveries of fines up to 90% at feed loads of 30 vol.%, separation sharpness x{sub 25}/x{sub 75} up to 0.83, without bypass and cut sizes down to 1.4 {micro}m (x{sub 50} from separation efficiency curve).

  11. Impact of clarification strategy on chromatographic separations: Pre-processing of cell homogenates.

    Science.gov (United States)

    Bracewell, D G; Boychyn, M; Baldascini, H; Storey, S A; Bulmer, M; More, J; Hoare, M

    2008-08-01

    This research focused on how the extent and type of primary solid-liquid separation can affect the performance of guard filtration and chromatography, in this instance hydrophobic interaction chromatography. The system used in the study was yeast (Saccharomyces cerevisiae) with the target molecule being an intracellular protein; alcohol dehydrogenase (ADH). As expected, loading more poorly clarified suspensions (both centrates and primary filtrates) required proportionally larger guard filtration areas. In addition for feed suspensions prepared by centrifugation, increased clarification led to greater column capacity. However, where filtration was used to achieve similar clarification considerably lower column capacity was achieved. These results were attributed to centrifugation leading to the aggregation of lipids and their subsequent removal in this form before application to the column. Clarification by filtration leaves such lipids in their original "soluble" state and hence they are not removed. The importance of the need to examine such interactive effects in bioprocess studies is discussed. This observation was confirmed with further analytical work into the nature of the aggregated material formed in the supernatant under centrifugation conditions. This material was only soluble in an organic solvent, and identified as phophatidylcholine and ergosterol as among the components removed by centrifugation and guard filtration as opposed to filtration and guard filtration.

  12. Hypolipidemic activities of xanthorrhizol purified from centrifugal TLC.

    Science.gov (United States)

    Oon, Seok Fang; Nallappan, Meenakshii; Kassim, Nur Kartinee; Shohaimi, Shamarina; Sa'ariwijaya, Mohd Shazrul Fazry; Tee, Thiam Tsui; Cheah, Yew Hoong

    2016-09-23

    Hyperlipidemia is defined as the presence of either hypertriglyceridemia or hypercholesterolemia, which could cause atherosclerosis. Although hyperlipidemia can be treated by hypolipidemic drugs, they are limited due to lack of effectiveness and safety. Previous studies demonstrated that xanthorrhizol (XNT) isolated from Curcuma xanthorrhizza Roxb. reduced the levels of free fatty acid and triglyceride in vivo. However, its ability to inhibit cholesterol uptake in HT29 colon cells and adipogenesis in 3T3-L1 cells are yet to be reported. In this study, XNT purified from centrifugal TLC demonstrated 98.3% purity, indicating it could be an alternative purification method. The IC50 values of XNT were 30.81 ± 0.78 μg/mL in HT29 cells and 35.07 ± 0.24 μg/mL in 3T3-L1 adipocytes, respectively. Cholesterol uptake inhibition study using HT29 colon cells showed that XNT (15 μg/mL) significantly inhibited the fluorescent cholesterol analogue NBD uptake by up to 27 ± 3.1% relative to control. On the other hand, higher concentration of XNT (50 μg/mL) significantly suppressed the growth of 3T3-L1 adipocytes (5.9 ± 0.58%) compared to 3T3-L1 preadipocytes (81.31 ± 0.55%). XNT was found to impede adipogenesis of 3T3-L1 adipocytes in a dose-dependent manner from 3.125 to 12.5 μg/mL, where 12.5 μg/mL significantly suppressed 36.13 ± 2.1% of lipid accumulation. We postulate that inhibition of cholesterol uptake, adipogenesis, preadipocyte and adipocyte number may be utilized as treatment modalities to reduce the prevalence of lipidemia. To conclude, XNT could be a potential hypolipidemic agent to improve cardiovascular health in the future.

  13. [Separation anxiety. Theoretical considerations].

    Science.gov (United States)

    Blandin, N; Parquet, P J; Bailly, D

    1994-01-01

    The interest in separation anxiety is nowadays increasing: this disorder appearing during childhood may predispose to the occurrence of anxiety disorders (such as panic disorder and agoraphobia) and major depression into adulthood. Psychoanalytic theories differ on the nature of separation anxiety and its place in child development. For some authors, separation anxiety must be understood as resulting from the unconscious internal conflicts inherent in the individuation process and gradual attainment of autonomy. From this point of view, the fear of loss of mother by separation is not regarded as resulting from a real danger. However, Freud considers the primary experience of separation from protecting mother as the prototype situation of anxiety and compares the situations generating fear to separation experiences. For him, anxiety originates from two factors: the physiological fact is initiated at the time of birth but the primary traumatic situation is the separation from mother. This point of view may be compared with behavioral theories. Behavioral theories suggest that separation anxiety may be conditioned or learned from innate fears. In Freud's theory, the primary situation of anxiety resulting from the separation from mother plays a role comparable to innate fears. Grappling with the problem of separation anxiety, Bowlby emphasizes then the importance of the child's attachment to one person (mother or primary caregiver) and the fact that this attachment is instinctive. This point of view, based on the watch of infants, is akin to ethological theories on behaviour of non human primates. Bowlby especially shows that the reactions of infant separated from mother evolve on three stages: the phase of protestation which may constitute the prototype of adulthood anxiety, the phase of desperation which may be the prototype of depression, and the phase of detachment. He emphasizes so the role of early separations in the development of vulnerability to depression

  14. Online Parameter Estimation for a Centrifugal Decanter System

    DEFF Research Database (Denmark)

    Larsen, Jesper Abildgaard; Alstrøm, Preben

    2014-01-01

    In many processing plants decanter systems are used for separation of heterogenious mixtures, and even though they account for a large fraction of the energy consumption, most decanters just runs at a fixed setpoint. Here, multi model estimation is applied to a waste water treatment plant...

  15. Separation of flow

    CERN Document Server

    Chang, Paul K

    2014-01-01

    Interdisciplinary and Advanced Topics in Science and Engineering, Volume 3: Separation of Flow presents the problem of the separation of fluid flow. This book provides information covering the fields of basic physical processes, analyses, and experiments concerning flow separation.Organized into 12 chapters, this volume begins with an overview of the flow separation on the body surface as discusses in various classical examples. This text then examines the analytical and experimental results of the laminar boundary layer of steady, two-dimensional flows in the subsonic speed range. Other chapt

  16. Separation of empty microcapsules after microencapsulation of porcine neonatal islets.

    Science.gov (United States)

    Shin, Soojeong; Yoo, Young Je

    2013-12-01

    Pancreatic islet transplantation is used to treat diabetes mellitus that has minimal complications and avoids hypoglycemic shock. Conformal microencapsulation of pancreatic islets improves their function by blocking immunogenic molecules while protecting fragile islets. However, production of empty alginate capsules during microencapsulation causes enlargement of the transplantation volume of the encapsulated islets and interferes with efficient transfer of nutrients and insulin. In this study, empty alginate capsules were separated after microencapsulation of neonatal porcine islet-like cell clusters (NPCC) using density-gradient centrifugation. Densities of NPCC and alginate capsules were determined using Percoll. Encapsulation products following alginate removal were 97 % of products, with less than 10 % of the capsules remaining empty. The viability of this process compared with manually-selected encapsulated islets indicates the separation process does not harm islets.

  17. Human colostral cells. I. Separation and characterization.

    Science.gov (United States)

    Crago, S S; Prince, S J; Pretlow, T G; McGhee, J R; Mestecky, J

    1979-12-01

    Analyses of the cells present in human colostrum obtained from fifty-four healthy donors during the first four days of lactation revealed that there were 3.3 x 10(6) (range 1.1 x 10(5)--1.2 x 10(7)) cells per ml of colostrum. Based on histochemical examinations, it was found that this population consisted of 30--47% macrophages, 40--60% polymorphonuclear leucocytes, 5.2--8.9% lymphocytes, and 1.3--2.8% colostral corpuscles; epithelial cells were rarely encountered. The identity of various cell types was confirmed by Wright's stain and by a series of histochemical techniques which disclosed the presence of non-specific esterase, peroxidase, and lipids. For further characterization, the different types of cells were separated by various methods, such as Ficoll-Hypaque density centrifugation, isokinetic centrifugation on a linear Ficoll gradient, adherence to glass or plastic, and phagocytosis of carbonyl iron. Immunohistochemical staining with FITC- and/or TRITC-labelled reagents to IgA, IgM, IgG, K- and lambda-chains, secretory component, lactoferrin, and alpha-lactalbumin were applied to unseparated as well as separated colostral cells. Polymorphonuclear leucocytes (staining for peroxidase) as well as macrophages and colostral corpuscles (staining for non-specific esterase) exhibited numerous intracellular vesicles that contained lipids as well as various combinations of milk proteins. Lymphoid cells did not stain with any of these reagents and plasma cells were not detected among the colostral cells. Individual phagocytic cells contained immunoglobulins of the IgA and IgM classes, both K and lambda light chains, secretory component, lactoferrin, and alpha-lactalbumin. The coincidental appearance of these proteins in single, phagocytic cells but not in lymphoid cells indicate that the cells acquired these proteins by ingestion from the environment. Markers commonly used for the identification of B lymphocytes (surface immunoglobulins) and T lymphocytes (receptors

  18. Effects of the number of inducer blades on the anti-cavitation characteristics and external performance of a centrifugal pump

    Energy Technology Data Exchange (ETDEWEB)

    Guo, XiaoMei; Shi, GaoPing [Zhejiang University of Water Resources and Electric Power, Hangzhou (China); Zhu, ZuChao; Cui, BaoLing [Zhejiang Sci-Tech University, Hangzhou (China)

    2016-07-15

    Installing an inducer upstream of the main impeller is an effective approach for improving the anti-cavitation performance of a high speed centrifugal pump. For a high-speed centrifugal pump with an inducer, the number of inducer blades can affect its internal flow and external performance. We studied the manner in which the number of inducer blades can affect the anti-cavitation characteristics and external performance of a centrifugal pump. We first use the Rayleigh-Plesset equation and the mixture model to simulate the vapor liquid flow in a centrifugal pump with an inducer, and then predict its external performance. Finally, we tested the external performance of a centrifugal pump with 2-, 3- and 4-bladed inducers, respectively. The results show that the simulations of external performance in a centrifugal pump are in accordance with our experiments. Based on this, we obtained vapor volume fraction distributions for the inducer, the impeller, and in the corresponding whole flow parts. We discovered that the vapor volume fraction of a centrifugal pump with a 3- bladed inducer is less than that of a centrifugal pump with 2- or 4-bladed inducers, which means that a centrifugal pump with a 3-bladed inducer has a better external and anti-cavitation performance.

  19. Centrifugal step emulsification applied for absolute quantification of nucleic acids by digital droplet RPA.

    Science.gov (United States)

    Schuler, Friedrich; Schwemmer, Frank; Trotter, Martin; Wadle, Simon; Zengerle, Roland; von Stetten, Felix; Paust, Nils

    2015-07-07

    Aqueous microdroplets provide miniaturized reaction compartments for numerous chemical, biochemical or pharmaceutical applications. We introduce centrifugal step emulsification for the fast and easy production of monodisperse droplets. Homogenous droplets with pre-selectable diameters in a range from 120 μm to 170 μm were generated with coefficients of variation of 2-4% and zero run-in time or dead volume. The droplet diameter depends on the nozzle geometry (depth, width, and step size) and interfacial tensions only. Droplet size is demonstrated to be independent of the dispersed phase flow rate between 0.01 and 1 μl s(-1), proving the robustness of the centrifugal approach. Centrifugal step emulsification can easily be combined with existing centrifugal microfluidic unit operations, is compatible to scalable manufacturing technologies such as thermoforming or injection moulding and enables fast emulsification (>500 droplets per second and nozzle) with minimal handling effort (2-3 pipetting steps). The centrifugal microfluidic droplet generation was used to perform the first digital droplet recombinase polymerase amplification (ddRPA). It was used for absolute quantification of Listeria monocytogenes DNA concentration standards with a total analysis time below 30 min. Compared to digital droplet polymerase chain reaction (ddPCR), with processing times of about 2 hours, the overall processing time of digital analysis was reduced by more than a factor of 4.

  20. Experimental Study on Series Operation of Sliding Vane Pump and Centrifugal Pump

    Directory of Open Access Journals (Sweden)

    Tao Li

    2013-01-01

    Full Text Available A platform for sliding vane pump and centrifugal pump tests is installed to study the series operation of them under different characteristics of pipeline. Firstly, the sliding vane pump and the centrifugal pump work independently, and the performance is recorded. Then, the two types of pumps are combined together, with the sliding vane pump acting as the feeding pump. Comparison is made between the performance of the independently working pump and the performance of series operation pump. Results show that the system flow rate is determined by the sliding vane pump. In order to ensure the stability of the series operation pumping system, the energy consumption required by the pipeline under the system flow should be greater than the pressure energy centrifugal pump can generate. Otherwise, the centrifugal pump can not operate stably, with reflux, swirl, gas-liquid two-phase flow in the runner and strong vibration and noise. The sliding vane pump can be in serial operation with the centrifugal pump under limited conditions.

  1. Influence of recovery method and centrifugation on epididymal sperm from collared peccaries (Pecari tajacu Linnaeus, 1758).

    Science.gov (United States)

    Bezerra, José Artur Brilhante; da Silva, Andréia Maria; Peixoto, Gislayne Christianne Xavier; da Silva, Mariana de Araújo; Franco de Oliveira, Moacir; Silva, Alexandre Rodrigues

    2014-05-01

    In order to establish protocols for gamete recovery from accidentally killed wild animals, or to take advantage of those slaughtered by captive breeders, we assess the influence of two methods on the recovery of epididymal sperm from collared peccaries, and verify the effect of centrifugation on such gametes. Genitalia from nine animals were used. For each animal, one epididymis was processed by flotation and the other was processed by retrograde flushing, both using a buffered media based on Tris. Following recovery, sperm were evaluated for motility, vigor, viability, functional membrane integrity, and morphology. A 1-mL aliquot of each sample was centrifuged, the supernatant removed, and the pellet suspended and evaluated as fresh samples. The sperm characteristics did not differ between the samples collected by flotation or retrograde flushing (P < 0.05). Centrifugation promoted an increase in head and tail defects, thus reducing the percentage of viable sperm (P < 0.05). No other parameter assessed for both methods was affected by centrifugation. In conclusion, epididymal sperm from collared peccaries can be efficiently collected through flotation or retrograde flushing, but not when either is followed by centrifugation.

  2. Effects of centrifugation on transmembrane water loss from normal and pathologic erythrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Kaperonis, A.A.; Chien, S.

    1989-02-01

    Plasma /sup 125/I-albumin was used as a marker of extracellular dilution in order to study the effect of high-speed centrifugation on transmembrane water distribution in several types of human red cells, including normal (AA), hemoglobin variants (beta A, AS, SC, beta S, and SS), and those from patients with hereditary spherocytosis. SS and AA erythrocytes were also examined for changes in intracellular hemoglobin concentration of three different density fractions and with increasing duration of spin. The minimum force and duration of centrifugation required to impair water permeability were found to vary with the red cell type, the anticoagulant used (heparin or EDTA), the initial hematocrit of the sample centrifuged, as well as among the individual erythrocyte fractions within the same sample. When subjecting pathologic erythrocytes to high-speed centrifugation, the /sup 125/I-albumin dilution technique can be used to determine whether the centrifugation procedure has led to an artifactual red cell water loss and to correct for this when it does occur. An abnormal membrane susceptibility to mechanical stress was demonstrated in erythrocytes from patients with hereditary spherocytosis and several hemoglobinopathies.

  3. Prediction and Reduction of Aerodynamic Noise of the Multiblade Centrifugal Fan

    Directory of Open Access Journals (Sweden)

    Shuiqing Zhou

    2014-08-01

    Full Text Available An aerodynamic and aeroacoustic investigation of the multiblade centrifugal fan is proposed in this paper, and a hybrid technique of combining flow field calculation and acoustic analysis is applied to solve the aeroacoustic problem of multiblade centrifugal fan. The unsteady flow field of the multiblade centrifugal fan is predicted by solving the incompressible Reynolds-averaged Navier-Stokes (RANS equations with conventional computing techniques for fluid dynamics. The principal noise source induced is extracted from the calculation of the flow field by using acoustic principles, and the modeled sources on inner and outer surfaces of the volute are calculated with multiregional boundary element method (BEM. Through qualitative analysis, the sound pressure amplitude distribution of the multiblade centrifugal fan in near field is given and the sound pressure level (SPL spectrum diagram of monitoring points in far field is obtained. Based on the analysis results, the volute tongue structure is adjusted and then a low-noise design for the centrifugal fan is proposed. The comparison of noise tests shows the noise reduction of improved fan model is more obvious, which is in good agreement with the prediction using the hybrid techniques.

  4. Determination of the Heat Transfer Coefficient at the Metal-Mold Interface During Centrifugal Casting

    Science.gov (United States)

    Vacca, Santiago; Martorano, Marcelo A.; Heringer, Romulo; Boccalini, Mário

    2015-05-01

    The heat transfer coefficient at the metal-mold interface ( h MM) has been determined for the first time during the centrifugal casting of a Fe-C alloy tube using the inverse solution method. To apply this method, a centrifugal casting experiment was carried out to measure cooling curves within the tube wall under a mold rotation speed of 900 rpm, imposing a centrifugal force 106 times as large as the gravity force (106 G). As part of the solution method, a comprehensive heat transfer model of the centrifugal casting was also developed and coupled to an optimization algorithm. Finally, the evolution of h MM with time that gives the minimum squared error between measured and calculated cooling curves was obtained. The determined h MM is approximately 870 W m-2 K-1 immediately after melt pouring, decreasing to about 50 W m-2 K-1 when the average temperature of the tube is ~973 K (700 °C), after the end of solidification. Despite the existence of a centrifugal force that could enhance the metal-mold contact, these values are lower than those generally reported for static molds with or without an insulating coating at the mold inner surface. The implemented model shows that the heat loss by radiation is dominant over that by convection at the tube inner surface, causing the formation of a solidification front that meets another front coming from the outer surface of the tube.

  5. Robust design optimization method for centrifugal impellers under surface roughness uncertainties due to blade fouling

    Science.gov (United States)

    Ju, Yaping; Zhang, Chuhua

    2016-03-01

    Blade fouling has been proved to be a great threat to compressor performance in operating stage. The current researches on fouling-induced performance degradations of centrifugal compressors are based mainly on simplified roughness models without taking into account the realistic factors such as spatial non-uniformity and randomness of the fouling-induced surface roughness. Moreover, little attention has been paid to the robust design optimization of centrifugal compressor impellers with considerations of blade fouling. In this paper, a multi-objective robust design optimization method is developed for centrifugal impellers under surface roughness uncertainties due to blade fouling. A three-dimensional surface roughness map is proposed to describe the nonuniformity and randomness of realistic fouling accumulations on blades. To lower computational cost in robust design optimization, the support vector regression (SVR) metamodel is combined with the Monte Carlo simulation (MCS) method to conduct the uncertainty analysis of fouled impeller performance. The analyzed results show that the critical fouled region associated with impeller performance degradations lies at the leading edge of blade tip. The SVR metamodel has been proved to be an efficient and accurate means in the detection of impeller performance variations caused by roughness uncertainties. After design optimization, the robust optimal design is found to be more efficient and less sensitive to fouling uncertainties while maintaining good impeller performance in the clean condition. This research proposes a systematic design optimization method for centrifugal compressors with considerations of blade fouling, providing a practical guidance to the design of advanced centrifugal compressors.

  6. Robust Design Optimization Method for Centrifugal Impellers under Surface Roughness Uncertainties Due to Blade Fouling

    Institute of Scientific and Technical Information of China (English)

    JU Yaping; ZHANG Chuhua

    2016-01-01

    Blade fouling has been proved to be a great threat to compressor performance in operating stage. The current researches on fouling-induced performance degradations of centrifugal compressors are based mainly on simplified roughness models without taking into account the realistic factors such as spatial non-uniformity and randomness of the fouling-induced surface roughness. Moreover, little attention has been paid to the robust design optimization of centrifugal compressor impellers with considerations of blade fouling. In this paper, a multi-objective robust design optimization method is developed for centrifugal impellers under surface roughness uncertainties due to blade fouling. A three-dimensional surface roughness map is proposed to describe the nonuniformity and randomness of realistic fouling accumulations on blades. To lower computational cost in robust design optimization, the support vector regression (SVR) metamodel is combined with the Monte Carlo simulation (MCS) method to conduct the uncertainty analysis of fouled impeller performance. The analyzed results show that the critical fouled region associated with impeller performance degradations lies at the leading edge of blade tip. The SVR metamodel has been proved to be an efficient and accurate means in the detection of impeller performance variations caused by roughness uncertainties. After design optimization, the robust optimal design is found to be more efficient and less sensitive to fouling uncertainties while maintaining good impeller performance in the clean condition. This research proposes a systematic design optimization method for centrifugal compressors with considerations of blade fouling, providing a practical guidance to the design of advanced centrifugal compressors.

  7. Integral centrifuges for olive oil extraction, at the third millenium threshold. Transformation yields

    Directory of Open Access Journals (Sweden)

    Ranalli, Alfonso

    1995-10-01

    Full Text Available A new-two, phase "decanter" (able to centrifuge the oily pastes without previous addition of hot water was compared with a three-phase one, processing homogeneous lots of three olive varieties (Coratina, Nebbio and Grossa di Cassano at an industrial level. The results showed that the integral centrifuge frequently yielded higher oil outputs. Furthermore, as the vegetation water was not separated from the husk, the amount liquid effluent produced was much lower (about 10 Kg/q olives, on average. This goes towards solving the age-old and very difficult problems connected with the production of this highly polluting outflow. However, the olive cake obtained semi-liquid (with about 55-60% of moisture, making the industrial recovery of the residual oil difficult and expensive. Furthermore, the solid by-product was characterized by higher percentage values of the oil amount, higher values of the pulp/stone ratio, as well as the greater weight produced. The effluent produced in small quantities, besides being more concentrated and thus richer in fat, dry residue, phenols and o-diphenols. The COD and turbidity values were also higher. Finally, as will be referred to in detail in the second part of this work, the oils obtained were of a far higher quality, mainly for their lower oxidizability and better organoleptic characteristic, so that they are wholly comparable to those extracted by pressing or filtering. In addition, the significant reduction of processing costs, as well as the lower consumption of hot water and electrical energy, must also be emphasized.

    El nuevo "decanter", a dos fases (capaz de centrifugar la pasta oleosa sin la dilución previa con agua caliente ha sido confrontado con el de a tres fases, elaborando, a nivel industrial, partidas homogéneas de tres variedades de aceitunas (Coratina, Nebbio y Grossa di Cassano. Los resultados de investigación han puesto de manifiesto que las centrifugadoras integrales permiten obtener

  8. The separation of adult separation anxiety disorder.

    Science.gov (United States)

    Baldwin, David S; Gordon, Robert; Abelli, Marianna; Pini, Stefano

    2016-08-01

    The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) categorization of mental disorders places "separation anxiety disorder" within the broad group of anxiety disorders, and its diagnosis no longer rests on establishing an onset during childhood or adolescence. In previous editions of DSM, it was included within the disorders usually first diagnosed in infancy, childhood, or adolescence, with the requirement for an onset of symptoms before the age of 18 years: symptomatic adults could only receive a retrospective diagnosis, based on establishing this early onset. The new position of separation anxiety disorder is based upon the findings of epidemiological studies that revealed the unexpectedly high prevalence of the condition in adults, often in individuals with an onset of symptoms after the teenage years; its prominent place within the DSM-5 group of anxiety disorders should encourage further research into its epidemiology, etiology, and treatment. This review examines the clinical features and boundaries of the condition, and offers guidance on how it can be distinguished from other anxiety disorders and other mental disorders in which "separation anxiety" may be apparent.

  9. Social Separation in Monkeys.

    Science.gov (United States)

    Mineka, Susan; Suomi, Stephen J.

    1978-01-01

    Reviews phenomena associated with social separation from attachment objects in nonhuman primates. Evaluates four theoretical treatments of separation in light of existing data: Bowlby's attachment-object-loss theory, Kaufman's conservation-withdrawal theory, Seligman's learned helplessness theory, and Solomon and Corbit's opponent-process theory.…

  10. Separation anxiety disorder

    NARCIS (Netherlands)

    Nauta, M.H.; Emmelkamp, P.M.G.; Sturmey, P.; Hersen, M.

    2012-01-01

    Separation anxiety disorder (SAD) is the only anxiety disorder that is specific to childhood; however, SAD has hardly ever been addressed as a separate disorder in clinical trials investigating treatment outcome. So far, only parent training has been developed specifically for SAD. This particular t

  11. Working with Separation

    Science.gov (United States)

    Krugman, Dorothy C.

    1971-01-01

    Discusses the role of the caseworker in providing support to children experiencing separation from their families and emphasizes the need to recognize that there are differences between those separation experiences dictated by the needs of children and those dictated by arbitrary or noncasework factors. (AJ)

  12. Nonterminal Separating Macro Grammars

    NARCIS (Netherlands)

    Hogendorp, Jan Anne; Asveld, P.R.J.; Nijholt, A.; Verbeek, Leo A.M.

    1987-01-01

    We extend the concept of nonterminal separating (or NTS) context-free grammar to nonterminal separating $m$-macro grammar where the mode of derivation $m$ is equal to "unrestricted". "outside-in' or "inside-out". Then we show some (partial) characterization results for these NTS $m$-macro grammars.

  13. Spiral microfluidic nanoparticle separators

    Science.gov (United States)

    Bhagat, Ali Asgar S.; Kuntaegowdanahalli, Sathyakumar S.; Dionysiou, Dionysios D.; Papautsky, Ian

    2008-02-01

    Nanoparticles have potential applications in many areas such as consumer products, health care, electronics, energy and other industries. As the use of nanoparticles in manufacturing increases, we anticipate a growing need to detect and measure particles of nanometer scale dimensions in fluids to control emissions of possible toxic nanoparticles. At present most particle separation techniques are based on membrane assisted filtering schemes. Unfortunately their efficiency is limited by the membrane pore size, making them inefficient for separating a wide range of sizes. In this paper, we propose a passive spiral microfluidic geometry for momentum-based particle separations. The proposed design is versatile and is capable of separating particulate mixtures over a wide dynamic range and we expect it will enable a variety of environmental, medical, or manufacturing applications that involve rapid separation of nanoparticles in real-world samples with a wide range of particle components.

  14. Centrifuge modelling of large diameter pile in sand subject to lateral loading

    DEFF Research Database (Denmark)

    Leth, Caspar Thrane

    and cyclic behaviour of large diameter rigid piles in dry sand by use of physical modelling. The physical modelling has been carried out at Department of Civil Engineering at the Danish Technical University (DTU.BYG), in the period from 2005 to 2009. The main centrifuge facilities, and especially...... the equipment for lateral load tests were at the start of the research in 2005 outdated and a major part of the work with the geotechnical centrifuge included renovation and upgrading of the facilities. The research with respect to testing of large diameter piles included:  Construction of equipment...... with embedment lengths of 6, 8 and 10 times the diameter. The tests have been carried out with a load eccentricity of 2.5 m to 6.5 m above the sand surface. The present report includes a description of the centrifuge facilities, applied test procedure and equipment along with presentation of the obtained results....

  15. Single-step fabrication of quantum funnels via centrifugal colloidal casting of nanoparticle films.

    KAUST Repository

    Kim, Jin Young

    2015-07-13

    Centrifugal casting of composites and ceramics has been widely employed to improve the mechanical and thermal properties of functional materials. This powerful method has yet to be deployed in the context of nanoparticles--yet size-effect tuning of quantum dots is among their most distinctive and application-relevant features. Here we report the first gradient nanoparticle films to be constructed in a single step. By creating a stable colloid of nanoparticles that are capped with electronic-conduction-compatible ligands we were able to leverage centrifugal casting for thin-films devices. This new method, termed centrifugal colloidal casting, is demonstrated to form films in a bandgap-ordered manner with efficient carrier funnelling towards the lowest energy layer. We constructed the first quantum-gradient photodiode to be formed in a single deposition step and, as a result of the gradient-enhanced electric field, experimentally measured the highest normalized detectivity of any colloidal quantum dot photodetector.

  16. A comparative evaluation of fluidized bed assisted drag finishing and centrifugal disk dry finishing

    Directory of Open Access Journals (Sweden)

    M. Barletta

    2014-06-01

    Full Text Available Drag finishing of brass (Cu-30 wt.% Zn rings using fluidized abrasives, which is a new finishing technology, is comparatively evaluated with centrifugal disk finishing. The comparison was performed by selecting the same abrasive granulates of two different sizes and operating the equipment for the same processing time or at their respective maximum speeds. The experimental analysis investigated the change in workpiece morphology, material removal during finishing and dimensional accuracy. The results showed that each of the types of equipment investigated in the study were capable of a high finishing performance with a relatively short processing time. However, fluidized bed assisted drag finishing was more effective than centrifugal disk finishing in both the achievable quality of the processed parts and reduced processing time. In contrast, centrifugal disk finishing was preferable whenever low erosion and stringent dimensional tolerances were demanded.

  17. Direct calculation of acceleration field through homogeneous transformation for two-axis centrifuge

    Institute of Scientific and Technical Information of China (English)

    吴广玉; 任顺清; 陈希军

    2003-01-01

    A precision centrifuge is an inertial navigation test equipment used for calibrating the characteristicsof accelerometers with high overloading, and a two-axis centrifuge can be used to generate either constant accel-eration or harmonic acceleration. The moving trajectory equation about the origin of the accelerometer coordinatesystem in a two-axis centrifuge was directly deduced through homogeneous transformation. The acceleration vec-tor of the origin in accelerometer coordinate system was achieved by making the second derivative of this trajec-tory equation. The acceleration components were acquired by decomposing this acceleration vector along thethree axes of the accelerometer coordinate system. The correctness of the homogeneous transformation was veri-fied through vector analysis.

  18. Enhanced versatility of fluid control in centrifugal microfluidic platforms using two degrees of freedom.

    Science.gov (United States)

    Cao, Xiaobao; deMello, A J; Elvira, K S

    2016-04-01

    Centrifugal microfluidic platforms have significant potential in commercial applications because of their operational flexibility and minimal external infrastructure requirements. However, the dynamic and real-time control of fluid flow within traditional centrifugal microfluidic platforms is problematic. To address this significant limitation, we propose a two degrees of freedom platform, in which a digital servo is located at each end of an arm driven by a motor. This allows for reversible inward pumping between multiple chambers with perfect efficiency. Furthermore, the addition of a second degree of freedom allows position-based pressure controlled burst valves to be accessed and operated in an independent fashion. To demonstrate the efficacy of this technical innovation, we show rapid and configurable flow switching between three target chambers within a centrifugal microfluidic device.

  19. On the saturation of the centrifugally excited curvature drift instability in AGN magnetospheres

    CERN Document Server

    Osmanov, Z

    2009-01-01

    We study a saturation process of the centrifugally driven curvature drift instability (CDI) in AGN magnetospheres close to the light cylinder surface to examine the twisting of magnetic field lines leading to the free motion of AGN winds, that completely kills the instability. Considering the Euler, continuity, and induction equations, by taking into account the resonant conditions, we derive the growth rate of the CDI. We show that due to the centrifugal effects, the rotational energy is efficiently pumped directly into the drift modes, that leads to the generation of a toroidal component of the magnetic field. As a result, the magnetic field lines transform into such a configuration when particles do not experience any forces and since the instability is centrifugally driven, at this stage the CDI is completely killed.

  20. Influence of Prewhirl Regulation by Inlet Guide Vanes on Cavitation Performance of a Centrifugal Pump

    Directory of Open Access Journals (Sweden)

    Lei Tan

    2014-02-01

    Full Text Available The influence of prewhirl regulation by inlet guide vanes (IGVs on a centrifugal pump performance is investigated experimentally and numerically. The experimental results show that IGVs can obviously change the head and increase the efficiency of the tested centrifugal pump over a wide range of flow rates. Although the cavitation performance is degraded, the variation of the cavitation critical point is less than 0.5 m. Movement of the computed three-dimensional streamlines in suction pipe and impeller are analyzed in order to reveal the mechanism how the IGVs realize the prewhirl regulation. The calculated results show that the influence of IGVs on the cavitation performance of centrifugal pump is limited by a maximum total pressure drop of 1777 Pa, about 7.6% of the total pressure at the suction pipe inlet for a prewhirl angle of 24°.