WorldWideScience

Sample records for centrifugal fast analyzers

  1. Environmental applications of the centrifugal fast analyzer

    International Nuclear Information System (INIS)

    Goldstein, G.; Strain, J.E.; Bowling, J.L.

    1975-12-01

    The centrifugal fast analyzer (GeMSAEC Fast Analyzer) was applied to the analysis of pollutants in air and water. Since data acquisition and processing are computer controlled, considerable effort went into devising appropriate software. A modified version of the standard FOCAL interpreter was developed which includes special machine language functions for data timing, acquisition, and storage, and also permits chaining together of programs stored on a disk. Programs were written and experimental procedures developed to implement spectrophotometric, turbidimetric, kinetic (including initial-rate, fixed-time, and variable-time techniques), and chemiluminescence methods of analysis. Analytical methods were developed for the following elements and compounds: SO 2 , O 3 , Ca, Cr, Cu, Fe, Mg, Se(IV), Zn, Cl - , I - , NO 2 - , PO 4 -3 , S -2 , and SO 4 -2 . In many cases, standard methods could be adapted to the centrifugal analyzer, in others new methods were employed. In general, analyses performed with the centrifugal fast analyzer were faster, more precise, and more accurate than with conventional instrumentation

  2. Centrifugal analyzer development

    International Nuclear Information System (INIS)

    Burtis, C.A.; Bauer, M.L.; Bostick, W.D.

    1976-01-01

    The development of the centrifuge fast analyzer (CFA) is reviewed. The development of a miniature CFA with computer data analysis is reported and applications for automated diagnostic chemical and hematological assays are discussed. A portable CFA system with microprocessor was adapted for field assays of air and water samples for environmental pollutants, including ammonia, nitrates, nitrites, phosphates, sulfates, and silica. 83 references

  3. Method and apparatus for automated processing and aliquoting of whole blood samples for analysis in a centrifugal fast analyzer

    Science.gov (United States)

    Burtis, C.A.; Johnson, W.F.; Walker, W.A.

    1985-08-05

    A rotor and disc assembly for use in a centrifugal fast analyzer. The assembly is designed to process multiple samples of whole blood followed by aliquoting of the resultant serum into precisely measured samples for subsequent chemical analysis. The assembly requires minimal operator involvement with no mechanical pipetting. The system comprises: (1) a whole blood sample disc; (2) a serum sample disc; (3) a sample preparation rotor; and (4) an analytical rotor. The blood sample disc and serum sample disc are designed with a plurality of precision bore capillary tubes arranged in a spoked array. Samples of blood are loaded into the blood sample disc by capillary action and centrifugally discharged into cavities of the sample preparation rotor where separation of serum and solids is accomplished. The serum is loaded into the capillaries of the serum sample disc by capillary action and subsequently centrifugally expelled into cuvettes of the analyticaly rotor for conventional methods. 5 figs.

  4. Method and apparatus for automated processing and aliquoting of whole blood samples for analysis in a centrifugal fast analyzer

    Science.gov (United States)

    Burtis, Carl A.; Johnson, Wayne F.; Walker, William A.

    1988-01-01

    A rotor and disc assembly for use in a centrifugal fast analyzer. The assembly is designed to process multiple samples of whole blood followed by aliquoting of the resultant serum into precisely measured samples for subsequent chemical analysis. The assembly requires minimal operator involvement with no mechanical pipetting. The system comprises (1) a whole blood sample disc, (2) a serum sample disc, (3) a sample preparation rotor, and (4) an analytical rotor. The blood sample disc and serum sample disc are designed with a plurality of precision bore capillary tubes arranged in a spoked array. Samples of blood are loaded into the blood sample disc in capillary tubes filled by capillary action and centrifugally discharged into cavities of the sample preparation rotor where separation of serum and solids is accomplished. The serum is loaded into the capillaries of the serum sample disc by capillary action and subsequently centrifugally expelled into cuvettes of the analytical rotor for analysis by conventional methods.

  5. 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...... components and molecular mass distribution of the lignin oils. The obtained lignin oil has a very different components composition when compared to a beech wood oil....

  6. Evaluation of automated enzyme immunoassays for five anticonvulsants and theophylline adapted to a centrifugal analyzer.

    Science.gov (United States)

    Urquhart, N; Godolphin, W; Campbell, D J

    1979-05-01

    We report a clinical evaluation of the enzyme immunoassay (EMIT) performed with the GEMSAEC centrifugal analyzer as compared to gas-liquid and liquid chromatography for anticonvulsant drugs and theophylline, respectively. A good correlation was obtained for all drugs, although some difficulties were experienced with one lot of reagent for ethosuximide. The analyzer has an economic advantage if many samples are being analyzed for few drugs in each sample.

  7. Valve for gas centrifuges

    Science.gov (United States)

    Hahs, Charles A.; Burbage, Charles H.

    1984-01-01

    The invention is a pneumatically operated valve assembly for simultaneously (1) closing gas-transfer lines connected to a gas centrifuge or the like and (2) establishing a recycle path between two of the lines so closed. The valve assembly is especially designed to be compact, fast-acting, reliable, and comparatively inexpensive. It provides large reductions in capital costs for gas-centrifuge cascades.

  8. Observations on centrifugation: application to centrifuge development.

    Science.gov (United States)

    Roberts, T; Smith, M; Roberts, B

    1999-11-01

    This report outlines the background to the development of an automated, serial, discrete centrifuge, reporting on the criteria considered essential in such an instrument. We established the criteria by examining the detailed logistics of centrifuge operation in a hospital laboratory. The mean sample load per run, using six centrifuges, was 13.6 samples, and the user-selectable cycle time ranged from 00:01:10 to 00:12:33 (hours:minutes:seconds) with a fixed g value of 1050. During the laboratory working window, (0900-1700), only 50% of the centrifuge capacity was utilized and more than one-third of the sample workload was delayed for >5 min because the centrifuges were not emptied promptly. In addition, 35% of the sample workload was centrifuged for less than the time prescribed in the operational specifications. Based on these findings, we designed a new continuous, serial centrifuge to overcome some of the deficiencies noted in the logistics study. The centrifuge operates continuously, nominally treating 150 samples/h, with a cycle time of 5 min at 1,000 g. The cycle time and g value are variable between limits, and their selection governs the throughput rate. Each sample is centrifuged separately in individual rotors mounted in a sturdy carousel with a periphery that traverses a load/unload station. There is no sample delay because of operator absence, and the capacity is fully utilized. The centrifuge can operate in a stand-alone capacity or has the capability of being integrated into a sample preparation system or as a direct front end for high-throughput analyzers.

  9. 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.

  10. Contribution to the study of liquid-liquid extraction dynamics in the case of fast transfers. Extractions of uranium, plutonium and neptunium in a laboratory centrifugal extractor

    International Nuclear Information System (INIS)

    Bergeonneau, Philippe

    1978-01-01

    The liquid-liquid extraction (also named solvent-based extraction) is a very important technique for the reprocessing of irradiated nuclear fuels. This research thesis is based on the use of a laboratory centrifugal extractor which allows interesting conditions to be achieved: fast transfer due to an intense solution mixing, very short duration of contact between solutions. Thus, after a report of a bibliographical study on chemical mechanisms of extraction, on the composition of extracted species, on extraction kinetics, and on centrifugal extractors, this thesis reports the design, fabrication and use of a centrifugal extractor: presentation of fundamental principles, description and characteristics (materials, hydrodynamic operation test and problems, prototype). It reports studies of fast transfer kinetics: mathematical processing, result interpretation, results and discussions of extraction kinetics for nitric acid, uranium VI and IV, plutonium IV, neptunium IV, and comparison of the different extraction kinetics

  11. Centrifugal trapping in the magnetotail

    Directory of Open Access Journals (Sweden)

    D. C. Delcourt

    1995-03-01

    Full Text Available Particles leaving the neutral sheet in the distant magnetotail at times display adiabatic trajectory sequences characterized by an inflection toward the equator and subsequent mirroring in its vicinity. We demonstrate that this low-latitude mirroring results primarily from a centrifugal deceleration due to the fast direction-changing E×B drift. This effect which we refer to as "centrifugal trapping" appears both in guiding centre and full particle treatments. It thus does not directly relate to nonadiabatic motion. However, pitch angle scattering due to nonadiabatic neutral sheet interaction does play a role in reducing the parallel speed of the particles. We show that centrifugal trapping is an important mechanism for the confinement of the slowest (typically below the equatorial E×B drift speed plasma sheet populations to the midplane vicinity.

  12. Centrifugal trapping in the magnetotail

    Directory of Open Access Journals (Sweden)

    D. C. Delcourt

    Full Text Available Particles leaving the neutral sheet in the distant magnetotail at times display adiabatic trajectory sequences characterized by an inflection toward the equator and subsequent mirroring in its vicinity. We demonstrate that this low-latitude mirroring results primarily from a centrifugal deceleration due to the fast direction-changing E×B drift. This effect which we refer to as "centrifugal trapping" appears both in guiding centre and full particle treatments. It thus does not directly relate to nonadiabatic motion. However, pitch angle scattering due to nonadiabatic neutral sheet interaction does play a role in reducing the parallel speed of the particles. We show that centrifugal trapping is an important mechanism for the confinement of the slowest (typically below the equatorial E×B drift speed plasma sheet populations to the midplane vicinity.

  13. Unexpected properties of the centrifugal force

    International Nuclear Information System (INIS)

    Abramowicz, M.A.

    1990-01-01

    Contrary to what is stated in the Newtonian dynamics, rotation of a reference frame is not sufficient for the occurrence of the centrifugal force. Instead, the necessary and sufficient condition is a motion along a path different from that of a photon trajectory in space. This calls for a rather fundamental change in understanding of the very nature of the centrifugal force. It also has important practical physical consequences: in a strong gravitational field, where light trajectories are substantially curved, centrifugal force is much weaker than the Newtonian theory predicts. In addition, when there are closed (circular) photon trajectories in space, the centrifugal force may reverse its direction - it attracts towards the rotation axis!. The weakening of the centrifugal force in strong gravitational fields and the reversal of its direction in the neighbourhood of close photon trajectories in space fully and clearly explain puzzling examples of counter intuitive behaviour of dynamical effects of rotation found previously by several authors: e.g. reversal of the ellipticity behaviour of the relativistic Maclaurin spheroids (Chandrasekhar and Miller, 1974), reversal of the viscous torque action (Anderson and Lemos, 1988), or the fact that rotation increases internal pressure of a sufficiently compact star (Abramowicz and Wagoner, 1974). Weakening of the centrifugal force implies that rotating neutron stars are less oblate (and probably more stable) than the Newtonian theory predicts. This is important for the recently discussed question of how fast can pulsars spin. (author). 23 refs, 3 figs

  14. Unexpected properties of the centrifugal force

    International Nuclear Information System (INIS)

    Abramowicz, M.A.

    1990-01-01

    Contrary to what is stated in the Newtonian dynamics, rotation of a reference frame is not sufficient for the occurrence of the centrifugal force. Instead, the necessary and sufficient condition is a motion along a path different from that of a photon trajectory in space. This calls for a rather fundamental change in understanding of the very nature of the centrifugal force. It also has important practical physical consequences: in a strong gravitational field, where light trajectories are substantially curved, centrifugal force is much weaker than the Newtonian theory predicts. In addition, when there are closed (circular) photon trajectories in space, the centrifugal force may reverse its direction - it attracts towards the rotation axis. The weakening of the centrifugal force in strong gravitational fields and the reversal of its direction in the neighborhood of close photon trajectories in space fully and clearly explain puzzling examples of counter intuitive behaviour of dynamical effects of rotation found previously by several authors: e.g. reversal of the ellipticity behaviour of the relativistic Maclaurin spheroids (Chandrasekhar and Miller, 1974), reversal of the viscous torque action (Anderson and Lemos, 1988) or the fact that rotation increases internal pressure of a sufficiently compact star (Abramowicz and Wagoner, 1974). Weakening of the centrifugal force implies that rotating neutron stars are less oblate (and probably more stable) than the Newtonian theory predicts. This is important for the recently discussed question of how fast can pulsars spins. (author). 31 refs, 3 figs

  15. Fluid dynamic interaction between water hammer and centrifugal pumps

    International Nuclear Information System (INIS)

    Ismaier, A.; Schluecker, E.

    2009-01-01

    Centrifugal pumps generate in piping systems noticeable pressure pulsations. In this paper the dynamic interaction between water hammer and pressure pulsations is presented. The experimental investigations were performed at a piping system with nominal diameter DN 100 (respectively NPS 4) and 75 m total length, built at the Institute for Process Technology and Machinery. Different measurements at this testing facility show that pulsating centrifugal pumps can damp pressure surges generated by fast valve closing. It is also shown that 1-dimensional fluid codes can be used to calculate this phenomenon. Furthermore it is presented that pressure surges pass centrifugal pumps almost unhindered, because they are hydraulic open.

  16. Development of centrifugal contactor for FBR fuel reprocessing

    International Nuclear Information System (INIS)

    Washiya, Tadahiro; Takeuchi, Masayuki; Suganuma, Takashi; Aose, Shinichi; Ogino, Hideki

    2003-01-01

    In the Feasibility Study on Commercialized Fast Reactor Cycle Systems, the aqueous reprocessing technology is nominated as a candidate for future reprocessing system, which supposes to apply a centrifugal contactor in the extraction process. For the reprocessing plant, the centrifugal contactor has great advantages such as reducing solvent degradation, improving of equipment utilization rate, compact designing of equipment layout and critical safety domination. From these advantages, the centrifugal contactor is crucial equipment in the aqueous reprocessing process. Since 1985, JNC has been developing the centrifugal contactor. The single unit development has been accomplished and basic characteristics such as extraction performance, fluidic performance and remote maintenance performance have been determined. A durability test has been conducted for high longevity, with consideration given to the nitric acid mist and estimation of the equipment lifetime. System test equipment with centrifugal contactors of engineering scale was installed, and uranium test was conducted. Up to now, a standard flow sheet test in the extraction process and mal-operation test assuming the one stage shutdown condition have been performed. (author)

  17. Centrifugation speed affects light transmission aggregometry.

    Science.gov (United States)

    Merolla, M; Nardi, M A; Berger, J S

    2012-02-01

    Light transmission aggregometry (LTA) is considered the gold standard for investigating platelet activity ex vivo. However, LTA protocols are not standardized, and differences in LTA procedure are a potential source of variance in results. Centrifugation speed is an essential component of platelet preparation in LTA, has yet to be standardized, and may affect platelet aggregation results. We sought to investigate the effect of relative centrifugal force (RCF) intensity on LTA results. Ten healthy controls had venous blood drawn and centrifuged at 150, 200, 300, and 500 g for 10 min. Cell counts in whole blood and platelet-rich plasma (PRP) were measured using a hematology analyzer. LTA was performed using 1.0 μm adenosine diphosphate (ADP) and 0.4 μm epinephrine as an agonist. Aggregation (%) was compared at 60, 120, 180, and 300 s and at maximum aggregation. Centrifugation speed was associated with decreasing platelet count (P centrifuge RCF at 60, 120, 180, 300 s and at maximum aggregation (P centrifugation speed in the interpretation of LTA results, supporting the need for standardization of centrifugation RCF in LTA protocols. © 2011 Blackwell Publishing Ltd.

  18. Centrifuge advances using HTS magnetic bearings

    Science.gov (United States)

    Werfel, F. N.; Flögel-Delor, U.; Rothfeld, R.; Wippich, D.; Riedel, T.

    2001-05-01

    Passive magnetic bearings are of increasing technical interest. We performed experiments with centrifugal rotors to analyze gyroscopic forces in terms imbalance, rotor elasticity and damping. Centrifuge rotors need to be operated soft and stable without whirling the sediments. In order to evaluate optimal parameters critical and resonance behaviors are investigated. Eccentricities up 2 mm are safely passed by accelerating test wheels. In a simple model we describe the effect of passing critical rotational speeds. Measurements of bearing properties and wheel performance are presented. We have constructed a first prototype centrifuge designed with a HTS double bearing which operates a titanium rotor safely up to 30 000 rpm. A 15 W Stirling cooler serves cryogenics of the YBCO stators. From the experiments design guidelines for centrifugal applications with HTS bearings are given.

  19. [The analytical setting of rotary speed of centrifuge rotor and centrifugation time in chemical, biochemical and microbiological practice].

    Science.gov (United States)

    Zolotarev, K V

    2012-08-01

    The researchers happen to face with suspensions in their chemical, biochemical and microbiological practice. The suspensions are the disperse systems with solid dispersed phase and liquid dispersion medium and with dispersed phase particle size > 100 nm (10-7 m). Quite often the necessity occurs to separate solid particles from liquid. To use for this purpose the precipitation in gravitation field can make the process to progress too long. In this respect an effective mode is the precipitation in the field of centrifugal forces--the centrifugation. The rotary speed of centrifuge rotor and centrifugation time can be set analytically using regularities of general dynamics and hydrodynamics. To this effect, should be written and transformed the equation of First and Second Newton Laws for suspension particle being in the field of centrifugal forces and forces of resistance of liquid and vessel wall. The force of liquid resistance depends on particle motion condition in liquid. To determine the regimen the Archimedes and Reynolds numerical dimensionless criteria are to be applied. The article demonstrates the results of these transformations as analytical inverse ratio dependence of centrifugation time from rotary speed. The calculation of series of "rate-time" data permits to choose the optimal data pair on the assumption of centrifuge capacity and practical reasonability. The results of calculations are validated by actual experimental data hence the physical mathematical apparatus can be considered as effective one. The setting progress depends both from parameter (Reynolds criterion) and data series calculation. So, the most convenient way to apply this operation is the programming approach. The article proposes to use the program Microsoft Excel and VBA programming language for this purpose. The possibility to download the file from Internet to use it for fast solution is proposed.

  20. 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.

  1. 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.

  2. Multiphase CFD simulation of a solid bowl centrifuge

    Energy Technology Data Exchange (ETDEWEB)

    Romani Fernandez, X.; Nirschl, H. [Universitaet Karlsruhe, Institut fuer MVM, Karlsruhe (Germany)

    2009-05-15

    This study presents some results from the numerical simulation of the flow in an industrial solid bowl centrifuge used for particle separation in industrial fluid processing. The computational fluid dynamics (CFD) software Fluent was used to simulate this multiphase flow. Simplified two-dimensional and three-dimensional geometries were built and meshed from the real centrifuge geometry. The CFD results show a boundary layer of axially fast moving fluid at the gas-liquid interface. Below this layer there is a thin recirculation. The obtained tangential velocity values are lower than the ones for the rigid-body motion. Also, the trajectories of the solid particles are evaluated. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  3. Plasma centrifuge

    International Nuclear Information System (INIS)

    Ikehata, Takashi; Mase, Hiroshi

    1998-01-01

    The plasma centrifuge is one of statistical isotope separation processes which uses the centrifugal force of a J x B driven rotating plasma in a magnetic field to give rise to the mass-dependent radial transport of isotopic ions. The system has been developed as an alternative to the gas centrifuge because a much higher rotational velocity and separation factor have been achieved. In this review, the physical aspects of the plasma centrifuge followed by the recent experimental achievements are described, especially in comparison with the gas centrifuge. (author)

  4. Subjective estimates of G-load in centrifuge-based simulation and applications for G-cueing in Desdemona

    NARCIS (Netherlands)

    Correia Grácio, B.J.; Wentink, M.; Groen, E.; Bles, W.

    2009-01-01

    In centrifuge simulators pilots experience the G-forces and fast G-onsets encountered in the real fighter aircraft. The motion cueing principle that drives these simulators is based on creating G-forces by increasing the centripetal force of the centrifuge through a rotation of the simulator arm.

  5. Fluorimetric methods for the measurement of intermediate metabolites (lactate, pyruvate, alanine, β-hydroxybutyrate, glycerol) using a COBAS FARA centrifugal analyser

    OpenAIRE

    Monti, L. D.; Sandoli, P. E.; Costa, S.; Phan, V. C.; Piatti, P. M.

    1993-01-01

    Intermediate products of the metabolism of glucose, fat and amino-acid are important in the evaluation of such metabolic disorders as diabetes mellitus, liver disease and metabolic acidosis. In the present study, methods for the measurement of intermediate metabolites (lactate, pyruvate, alanine, β-hydroxybutyrate and glycerol) have been adapted to a fast centrifugal analyzer: the COBAS FARA. Correlation coeffcients rangedfrom 0.90 to 0.99, compared to established manual spectrophotometric me...

  6. Fast neutron flux analyzer with real-time digital pulse shape discrimination

    Energy Technology Data Exchange (ETDEWEB)

    Ivanova, A.A., E-mail: a.a.ivanova@inp.nsk.su [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Zubarev, P.V. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Novosibirsk State Technical University, 630092 Novosibirsk (Russian Federation); Ivanenko, S.V. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Khilchenko, A.D. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Novosibirsk State Technical University, 630092 Novosibirsk (Russian Federation); Kotelnikov, A.I. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Polosatkin, S.V. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Novosibirsk State Technical University, 630092 Novosibirsk (Russian Federation); Novosibirsk State University, 630090 Novosibirsk (Russian Federation); Puryga, E.A.; Shvyrev, V.G. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Novosibirsk State Technical University, 630092 Novosibirsk (Russian Federation); Sulyaev, Yu.S. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 630090 Novosibirsk (Russian Federation)

    2016-08-11

    Investigation of subthermonuclear plasma confinement and heating in magnetic fusion devices such as GOL–3 and GDT at the Budker Institute (Novosibirsk, Russia) requires sophisticated equipment for neutron-, gamma- diagnostics and upgrading data acquisition systems with online data processing. Measurement of fast neutron flux with stilbene scintillation detectors raised the problem of discrimination of the neutrons (n) from background cosmic particles (muons) and neutron-induced gamma rays (γ). This paper describes a fast neutron flux analyzer with real-time digital pulse-shape discrimination (DPSD) algorithm FPGA-implemented for the GOL–3 and GDT devices. This analyzer was tested and calibrated with the help of {sup 137}Cs and {sup 252}Cf radiation sources. The Figures of Merit (FOM) calculated for different energy cuts are presented. - Highlights: • Electronic equipment for measurement of fast neutron flux with stilbene scintillator is presented. • FPGA-implemented digital pulse-shape discrimination algorithm by charge comparison method is shown. • Calibration of analyzer was carried out with {sup 137}Cs and {sup 252}Cf. • Figures of Merit (FOM) values for energy cuts from 1/8 Cs to 2 Cs are from 1.264 to 2.34 respectively.

  7. Annular centrifugal contactors for TRPO process test

    International Nuclear Information System (INIS)

    Duan, W.H.; Wang, J.C.; Chen, J.; Zhou, X.Z.; Zhou, J.Z.; Song, C.L.

    2005-01-01

    The TRPO process has been developed in China for removing TRU elements from high-level liquid waste (HLLW) since 1980s. Centrifugal contactors have several advantages such as low hold-up volume, short residence time, low solvent degradation, small space requirements and short start-up time. Therefore, they are favored for both the reprocessing of spent fuel and the treatment of HLLW. In order to meet study on the TRPO test, a series of annular centrifugal contactors have been developed in Institute of Nuclear and -New Energy Technology, Tsinghua University, China (INET). In particular, the 10-mm annular centrifugal contactor for the laboratory-scale test has been applied successfully in the cold and hot tests of the TRPO process. The 70-mm annular centrifugal contactor for the industry-scale test has two new design characteristics, namely a modular design and an overflow structure. The modular design makes the contactor to be disassembled and assembled fast by simply moving the modules up and down. With the overflow structure, even though one stage or non-adjacent stages of the multi-stage cascade in operation are ceased to work, the cascade can continue to operate. Both the hydraulic performance and the mass-transfer efficiency of these contactors are excellent, and the extraction stage efficiency is greater than 95% at suitable operating conditions.

  8. 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.

  9. 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

  10. 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.

  11. Theory of uranium enrichment by the gas centrifuge

    Energy Technology Data Exchange (ETDEWEB)

    Olander, D R [California Univ., Berkeley (USA). Lawrence Berkeley Lab.; California Univ., Berkeley (USA). Dept. of Nuclear Engineering)

    1981-01-01

    Onsager's analysis of the hydrodynamics of fluid circulation in the boundary layer on the rotor wall of a gas centrifuge is reviewed. The description of the flow in the boundary layers on the top and bottom end caps due to Carrier and Maslen is summarized. The method developed by Wood and Morton of coupling the flow models in the rotor wall and end cap boundary layers to complete the hydrodynamic analysis of the centrifuge is presented. Mechanical and thermal methods of driving the internal gas circulation are described. The isotope enrichment which results from the superposition of the elementary separation effect due to the centrifugal field in the gas and its internal circulation is analyzed by the Onsager-Cohen theory. The performance function representing the optimized separative power of a centrifuge as a function of throughput and cut is calculated for several simplified internal flow models. The use of asymmetric ideal cascades to exploit the distinctive features of centrifuge performance functions is illustrated.

  12. Separations by centrifugal phenomena

    International Nuclear Information System (INIS)

    Hsu, H.W.

    1981-01-01

    The technical information presented herein emphasizes the uniqueness of the centrifugal separations methodology and pertinent theory for various kinds of centrifugation. The topics are arranged according to gas, liquid, and solid phases, in the order of increasing densities. Much space is devoted to liquid centrifugation because of the importance of this technique in chemical and biological laboratories. Many separational and characterizational examples are illustrated in detail. The material has been divided into 7 chapters entitled: 1) Introduction, 2) Basic Theory of Centrifugation, 3) Gas Centrifuges, 4) Preparative Liquid Centrifuges, 5) Analytical Liquid Centrifuges, 6) Liquid Centrifuges in Practice, and 7) Mechanical Separations by Centrifuges. Separate abstracts have been prepared for each chapter except the introduction

  13. Development of centrifugal contactors [Paper No. : IIIB-5

    International Nuclear Information System (INIS)

    Koganti, S.B.; Nagarajan, S.; Balasubramanian, G.R.

    1979-01-01

    Development of short residence contactors is one of the main objectives of Reprocessing Programme for fast reactor fuels in Reactor Research Centre, Kalpakkam. Paper discusses the suitability of centrifugal contactor as one of the candidate solvent contactors. Description of various stages of development of this work in the Reprocessing Development Laboratory, RRC and also characteristics of small contactor developed are given. (author)

  14. Flow and separation in gas centrifuge with Beams type circulation

    International Nuclear Information System (INIS)

    Ajsen, Eh.M.; Borisevich, V.D.; Levin, E.V.

    1992-01-01

    Structure of the secondary circulation flows in the working chamber of gas centrifuge for uranium isotope separation is studied using the numerical methods. Influence of the circulation thermal component on the centrifuge efficiency is analyzed. The contribution of useful component concentration difference of binary isotope mixture in feeding flows to the centrifuge efficiency is determined. Dependence of concentration optimal difference, whereby the maximum efficiency is achieved, on temperature distribution on the rotor side wall is found

  15. Centrifugal dewatering of acid casein curd: effect of casein manufacturing and centrifugation variables on curd compression in a laboratory centrifuge.

    Science.gov (United States)

    Munro, P A; Van Til, H J

    1988-10-20

    Data relevant to curd compression in a horizontal, solid bowl decanter centrifuge have been obtained by studying the dewatering of acid casein curd in a batch laboratory centrifuge. Analysis of curd compression under centrifugal force predicts a moisture content gradient in the dewatered curd from a maximum at the curd-liquid interface to a minimum at the centrifuge bowl wall. This moisture content gradient was also measured experimentally, and its practical implications are discussed. Increases in centrifugal force, centrifugation time, and centrifugation temperature all caused a marked de crease in dewatered curd moisture content, whereas in creases in precipitation pH and maximum washing temperature caused a smaller decrease in dewatered curd moisture content.

  16. Centrifugation

    International Nuclear Information System (INIS)

    Subbaramajer.

    1983-01-01

    The theoretical analysis of the processes taking place at centrifugal method of isotope separation taking into account the latest investigations, in particular, investigation of velocity field applying the theory of boundary layers in rotating gas is conducted. As a result of using power computers for the solution of hydrodynamics equations by numerical methods sufficiently exact solutions of main hydrodynamic equations, reflecting the real centrifuge construction are derived. The increase of calculation accuracy of the flow field reflected also on the accuracy of the diffusion equation solution. Three parameters of similarity (height of transfer unit, flow, mass transfer coefficient) and their connection with the flow field, elementary separation coefficient in a cetrifugal field and molecular diffusion coefficient is determined. Modified formulas for the separation coefficient and separation centrifuge power taking into account similarity parameter changes over the axis are derived. The possibility of determining the system of controlled parameters optimizing the separation centrifuge power is shown

  17. Cyber meets nuclear - Stuxnet and the cyberattacks on Iranian centrifuges

    Energy Technology Data Exchange (ETDEWEB)

    Englert, Matthias [IANUS, TU Darmstadt (Germany)

    2013-07-01

    In 2010 the computer worm Stuxnet attacked the information hardware of the Iranian uranium enrichment program. Stuxnet spread by USB flash drives and attacked SCADA software installed on Windows systems via several zero-day exploits. SCADA configures programmable logic controllers which control in the case of the Iranian centrifuge cascades frequency converter drives to choose the frequency of centrifuge motors. Thus the attackers were able to either change the rotation frequency of the rotor and thereby the separative power of the centrifuge or even destroy the fast spinning centrifuges by stopping and restarting them. The designers of Stuxnet must have had intimate knowledge of the facility design as e.g. the cascade connection scheme was programmed into Stuxnet. Based on this information some calculations of the Iranian cascade regarding the potential to produce highly enriched uranium will be presented using cascade simulation tools. The use of such highly sophisticated computer attacks to sabotage a nuclear program shed a new light on the debate about cyber attacks and the use of information technology for kinetic attacks in general. The talk will address problems the weaponization of information technology poses for international security and will highlight some more recent developments.

  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 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...... from centrifuge tests performed on large diameter piles installed in dry sand....

  19. CENTRIFUGE END CAP

    Science.gov (United States)

    Beams, J.W.; Snoddy, L.B.

    1960-08-01

    An end cap for ultra-gas centrifuges is designed to impart or remove angular momentum to or from the gas and to bring the entering gas to the temperature of the gas inside the centrifuge. The end cap is provided with slots or fins for adjusting the temperature and the angular momentum of the entering gas to the temperature and momentum of the gas in the centrifuge and is constructed to introduce both the inner and the peripheral stream into the centrifuge.

  20. 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

  1. Centrifuge enrichment program

    International Nuclear Information System (INIS)

    Astley, E.R.

    1976-01-01

    Exxon Nuclear has been active in privately funded research and development of centrifuge enrichment technology since 1972. In October of 1975, Exxon Nuclear submitted a proposal to design, construct, and operate a 3000-MT SWU/yr centrifuge enrichment plant, under the provisions of the proposed Nuclear Fuel Assurance Act of 1975. The U.S. Energy Research and Development Administration (ERDA) accepted the proposal as a basis for negotiation. It was proposed to build a 1000-MT SWU/yr demonstration increment to be operational in 1982; and after successful operation for about one year, expand the facilities into a 3000-MT SWU/yr plant. As part of the overall centrifuge enrichment plant, a dedicated centrifuge manufacturing plant would be constructed; sized to support the full 3000-MT SWU/yr plant. The selection of the centrifuge process by Exxon Nuclear was based on an extremely thorough evaluation of current and projected enrichment technology; results show that the technology is mature and the process will be cost effective. The substantial savings in energy (about 93%) from utilization of the centrifuge option rather than gaseous diffusion is a compelling argument. As part of this program, Exxon Nuclear has a large hardware R and D program, plus a prototype centrifuge manufacturing capability in Malta, New York. To provide a full-scale machine and limited cascade test capability, Exxon Nuclear is constructing a $4,000,000 Centrifuge Test Facility in Richland, Washington. This facility was to initiate operations in the Fall of 1976. Exxon Nuclear is convinced that the centrifuge enrichment process is the rational selection for emergence of a commercial enrichment industry

  2. Mathematical model of secondary rotor of centrifuge based on magnetic or electromagnetic overhead and bottom viscous damper taking into account flexibility and viscosity of rotor, and program of calculating dynamics of rotor in centrifuge

    International Nuclear Information System (INIS)

    Andronov, I.N.

    1999-01-01

    The attempts to development of the rotor-dampers universal model with ability of fast correction of the parameters of mock-up rotor and dampers, their construction were made. The model that takes into account viscous characteristics of the material of the centrifuge rotor and allows research numerically into the rotor behaviour during over-speeding is suggested. The examples of calculations as show good effect of electromagnetic damping on the dynamics of the centrifuge rotor are given [ru

  3. Centrifugal Pump Effect on Average Particle Diameter of Oil-Water Emulsion

    Science.gov (United States)

    Morozova, A.; Eskin, A.

    2017-11-01

    In this paper we review the process of oil-water emulsion particles fragmentation in a turbulent flow created by a centrifugal pump. We examined the influence of time necessary for oil-water emulsion preparation on the particle size of oil products and the dependence of a centrifugal pump emulsifying capacity on the initial emulsion dispersion. The investigated emulsion contained the brand fuel oil M-100 and tap water; it was sprayed with a nozzle in a gas-water flare. After preparation of the emulsion, the centrifugal pump was turned on and the emulsion samples were taken before and after the pump passing in 15, 30 and 45 minutes of spraying. To determine the effect the centrifugal pump has on the dispersion of the oil-water emulsion, the mean particle diameter of the emulsion particles was determined by the optical and microscopic method before and after the pump passing. A dispersion analysis of the particles contained in the emulsion was carried out by a laser diffraction analyzer. By analyzing the pictures of the emulsion samples, it was determined that after the centrifugal pump operation a particle size of oil products decreases. This result is also confirmed by the distribution of the obtained analyzer where the content of fine particles with a diameter less than 10 μm increased from 12% to 23%. In case of increasing emulsion preparation time, a particle size of petroleum products also decreases.

  4. 75 FR 70300 - USEC, Inc.; American Centrifuge Lead Cascade Facility; American Centrifuge Plant; Notice of...

    Science.gov (United States)

    2010-11-17

    ... Centrifuge Lead Cascade Facility; American Centrifuge Plant; Notice of Receipt of a License Transfer... SNM-2011, for the American Centrifuge Lead Cascade Facility and the American Centrifuge Plant... USEC Inc., (the Licensee), for its American Centrifuge Lead Cascade Facility (LCF) and American...

  5. CENTRIFUGE

    Science.gov (United States)

    Rushing, F.C.

    1960-09-01

    A vibration damping mechanism for damping vibration forces occurring during the operation of a centrifuge is described. The vibration damping mechanism comprises a plurality of nested spaced cylindrical elements surrounding the rotating shaft of the centrifuge. Some of the elements are held substantially stationary while the others are held with respect to a pair of hearings spaced along the rotating shaft. A fluid is retained about the cylindrical elements.

  6. Dynamics and stability of a tethered centrifuge in low earth orbit

    Science.gov (United States)

    Quadrelli, B. M.; Lorenzini, E. C.

    1992-01-01

    The three-dimensional attitude dynamics of a spaceborne tethered centrifuge for artificial gravity experiments in low earth orbit is analyzed using two different methods. First, the tethered centrifuge is modeled as a dumbbell with a straight viscoelastic tether, point tip-masses, and sophisticated environmental models such as nonspherical gravity, thermal perturbations, and a dynamic atmospheric model. The motion of the centrifuge during spin-up, de-spin, and steady-rotation is then simulated. Second, a continuum model of the tether is developed for analyzing the stability of lateral tether oscillations. Results indicate that the maximum fluctuation about the 1-g radial acceleration level is less than 0.001 g; the time required for spin-up and de-spin is less than one orbit; and lateral oscillations are stable for any practical values of the system parameters.

  7. RESEARCH CENTRIFUGE- ADVANCED TOOL SEPERATION

    OpenAIRE

    Mahajan Ashwini; Prof. B.V. Jain; Dr Surajj Sarode

    2015-01-01

    A centrifuge is a critical piece of equipment for the laboratory. Purpose of this study was to study research centrifuge in detail, its applications, uses in different branches and silent features. Their are two types of research centrifuge study here revolutionary research centrifuge and microprocessor research centrifuge. A centrifuge is a device that separates particles from a solution through use of a rotor. In biology, the particles are usually cells, sub cellular organelles, or large mo...

  8. Pipeline system for gas centrifuge

    International Nuclear Information System (INIS)

    Masumoto, Tsutomu; Umezawa, Sadao.

    1977-01-01

    Purpose: To enable effective operation for the gas centrifuge cascade system upon failures in the system not by interrupting the operation of all of the centrifuges in the system but by excluding only the failed centrifuges. Constitution: A plurality of gas centrifuges are connected by way of a pipeline and an abnormal detector for the automatic detection of abnormality such as destruction in a vacuum barrel and loss of vacuum is provided to each of the centrifuges. Bypass lines for short-circuitting adjacent centrifuges are provided in the pipelines connecting the centrifuges. Upon generation of abnormality in a centrifuge, a valve disposed in the corresponding bypass is automatically closed or opened by a signal from the abnormal detector to change the gas flow to thereby exclude the centrifuge in abnormality out of the system. This enables to effectively operate the system without interrupting the operation for the entire system. (Moriyama, K.)

  9. Plasma centrifuges

    International Nuclear Information System (INIS)

    Karchevskij, A.I.; Potanin, E.P.

    2000-01-01

    The review of the most important studies on the isotope separation processes in the rotating plasma is presented. The device is described and the characteristics of operation of the pulse plasma centrifuges with weakly and strongly ionized plasma as well as the stationary plasma centrifuges with the medium weak ionization and devices, applying the stationary vacuum arc with the high ionization rate and the stationary beam-plasma discharge with complete ionization, are presented. The possible mechanisms of the isotope separation in plasma centrifuges are considered. The specific energy consumption for isotope separation in these devices is discussed [ru

  10. Investigation of Bond Strength in Centrifugal Lining of Babbitt on Cast Iron

    Science.gov (United States)

    Diouf, Papa; Jones, Alan

    2010-03-01

    The quality of the bond between Babbitt metal and a cast iron substrate was evaluated for centrifugal casting and static casting using the Chalmers bond strength method and scanning electron microscopy (SEM). The effect of three different centrifugal casting parameters, the speed of revolution, the pouring rate, and the cooling rate, was investigated. The bond strength and the microstructure at the bond interface were predominantly affected by the cooling rate, with a fast cooling rate resulting in better properties. The speed of revolution and the pouring rate only had a small effect on the bond strength, with faster revolution and faster pouring rate resulting in slightly better bonds.

  11. Design and calibration of a fast-time resolution charge exchange analyzer

    International Nuclear Information System (INIS)

    Scime, E.; Hokin, S.

    1992-04-01

    A five channel, fast time resolution, scanning charge exchange analyzer has been developed for the Madison Symmetric Torus (MST). The analyzer consists of an iron vacuum vessel, a gas stripping cell, an electrostatic bending field, and five continuous electron multiplier detectors. The incident neutral flux and operation of the detectors in current mode limits the time resolution of the analyzer to 10 μs. The analyzer was absolutely calibrated over the energy range of interest (500--2000 eV) with an H + beam, so that the charge exchange power loss could also be measured. The analyzer can be swiveled on a shot-to-shot basis for measurements of T i (r), where 0.3 < r/a < 0.7. The mechanical design was driven by the need for a low cost, expandable ion temperature diagnostic

  12. 76 FR 9613 - USEC Inc. (American Centrifuge Lead Cascade Facility and American Centrifuge Plant); Order...

    Science.gov (United States)

    2011-02-18

    ... NUCLEAR REGULATORY COMMISSION [EA-11-013] USEC Inc. (American Centrifuge Lead Cascade Facility and American Centrifuge Plant); Order Approving Direct Transfer of Licenses and Conforming Amendment I USEC... Centrifuge Lead Cascade Facility (Lead Cascade) and American Centrifuge Plant (ACP), respectively, which...

  13. 77 FR 9273 - USEC Inc. (American Centrifuge Lead Cascade Facility and American Centrifuge Plant); Direct...

    Science.gov (United States)

    2012-02-16

    ... NUCLEAR REGULATORY COMMISSION [NRC-2010-0355] USEC Inc. (American Centrifuge Lead Cascade Facility and American Centrifuge Plant); Direct Transfer of Licenses In the Matter of USEC INC. (American Centrifuge Lead Cascade Facility and American Centrifuge Plant); Order EA-12- [[Page 9274

  14. Gas Centrifuges and Nuclear Proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Albright, David

    2004-09-15

    Gas centrifuges have been an ideal enrichment method for a wide variety of countries. Many countries have built gas centrifuges to make enriched uranium for peaceful nuclear purposes. Other countries have secretly sought centrifuges to make highly enriched uranium for nuclear weapons. In more recent times, several countries have secretly sought or built gas centrifuges in regions of tension. The main countries that have been of interest in the last two decades have been Pakistan, Iraq, Iran, and North Korea. Currently, most attention is focused on Iran, Pakistan, and North Korea. These states did not have the indigenous abilities to make gas centrifuges, focusing instead on illicit and questionable foreign procurement. The presentation covered the following main sections: Spread of centrifuges through illicit procurement; Role of export controls in stopping proliferation; Increasing the transparency of gas centrifuge programs in non-nuclear weapon states; and, Verified dismantlement of gas centrifuge programs. Gas centrifuges are important providers of low enriched uranium for civil nuclear power reactors. They also pose special nuclear proliferation risks. We all have special responsibilities to prevent the spread of gas centrifuges into regions of tension and to mitigate the consequences of their spread into the Middle East, South Asia, and North Asia.

  15. Fast, controlled stepping drive for D2 filament ejection

    International Nuclear Information System (INIS)

    Amenda, W.; Lang, R.S.

    1985-01-01

    Centrifugal pellet injectors are required to refuel plasma machines. The pellet feed into the centrifuge should, if possible, be direct to keep the exit angle divergence small. The D 2 filaments used are first stored in a cryostat and then rapidly transported to the intake region of the centrifuge. An intermittent drive for fast, controlled ejection of D 2 filaments is described here. Mean filament speed of up to 0.6 m/s per step (1.2 mm) are achieved for the centrifugal pellet injector which refuels the ASDEX tokamak at Garching. The timing of the (81) step shifts can be synchronized with the rotor motion. The drive allows rates of up to 50 pellets per second. The drive method also seems to be suitable for direct feeding of other known centrifugal pellet injectors

  16. Quantification of platelets obtained by different centrifugation protocols in SHR rats

    Directory of Open Access Journals (Sweden)

    João Alberto Yazigi Junior

    2015-12-01

    Full Text Available ABSTRACT OBJECTIVE: To quantify the platelet concentration in the blood of SHR rats, by means of different centrifugation protocols, and to evaluate what the most effective method for obtaining platelets is. METHODS: We used 40 male rats of the isogenic SHR lineage. The animals were divided into three groups: control, using whole blood without centrifugation; single centrifugation, using whole blood subjected to a single centrifugation at 200 × gand 400 × g; and double centrifugation, using whole blood subjected one centrifugation at different rotations, followed by collection of whole plasma subjected to another centrifugation at different rotations: 200 × g+ 200 ×g; 200 × g+ 400 × g; 200 × g+ 800 × g; 400 ×g+ 400 × g; 400 × g+ 800 × g. Samples of 3 ml of blood were drawn from each animal by means of cardiac puncture. The blood was stored in Vacutainer collection tubes containing 3.2% sodium citrate. The blood from the control group animals was analyzed without being subjected to centrifugation. After the blood from the other groups of animals had been subjected to centrifugation, the whole plasma was collected and subjected to platelet counting in the lower third of the sample. RESULTS: We obtained greatest platelet enrichment in the subgroup with two centrifugations comprising 400 × gfor 10 min + 400 ×gfor 10 min, in which the mean platelet concentration was 11.30 times higher than that of the control group. CONCLUSION: It was possible to obtain a high platelet concentration using viable simple techniques, by means of centrifugation of whole blood and use of commonly used materials. The most effective method for obtaining platelet concentrate was found in samples subjected to two centrifugations.

  17. Review on stress corrosion and corrosion fatigue failure of centrifugal compressor impeller

    Science.gov (United States)

    Sun, Jiao; Chen, Songying; Qu, Yanpeng; Li, Jianfeng

    2015-03-01

    Corrosion failure, especially stress corrosion cracking and corrosion fatigue, is the main cause of centrifugal compressor impeller failure. And it is concealed and destructive. This paper summarizes the main theories of stress corrosion cracking and corrosion fatigue and its latest developments, and it also points out that existing stress corrosion cracking theories can be reduced to the anodic dissolution (AD), the hydrogen-induced cracking (HIC), and the combined AD and HIC mechanisms. The corrosion behavior and the mechanism of corrosion fatigue in the crack propagation stage are similar to stress corrosion cracking. The effects of stress ratio, loading frequency, and corrosive medium on the corrosion fatigue crack propagation rate are analyzed and summarized. The corrosion behavior and the mechanism of stress corrosion cracking and corrosion fatigue in corrosive environments, which contain sulfide, chlorides, and carbonate, are analyzed. The working environments of the centrifugal compressor impeller show the behavior and the mechanism of stress corrosion cracking and corrosion fatigue in different corrosive environments. The current research methods for centrifugal compressor impeller corrosion failure are analyzed. Physical analysis, numerical simulation, and the fluid-structure interaction method play an increasingly important role in the research on impeller deformation and stress distribution caused by the joint action of aerodynamic load and centrifugal load.

  18. A vibration model for centrifugal contactors

    International Nuclear Information System (INIS)

    Leonard, R.A.; Wasserman, M.O.; Wygmans, D.G.

    1992-11-01

    Using the transfer matrix method, we created the Excel worksheet ''Beam'' for analyzing vibrations in centrifugal contactors. With this worksheet, a user can calculate the first natural frequency of the motor/rotor system for a centrifugal contactor. We determined a typical value for the bearing stiffness (k B ) of a motor after measuring the k B value for three different motors. The k B value is an important parameter in this model, but it is not normally available for motors. The assumptions that we made in creating the Beam worksheet were verified by comparing the calculated results with those from a VAX computer program, BEAM IV. The Beam worksheet was applied to several contactor designs for which we have experimental data and found to work well

  19. SEAL FOR HIGH SPEED CENTRIFUGE

    Science.gov (United States)

    Skarstrom, C.W.

    1957-12-17

    A seal is described for a high speed centrifuge wherein the centrifugal force of rotation acts on the gasket to form a tight seal. The cylindrical rotating bowl of the centrifuge contains a closure member resting on a shoulder in the bowl wall having a lower surface containing bands of gasket material, parallel and adjacent to the cylinder wall. As the centrifuge speed increases, centrifugal force acts on the bands of gasket material forcing them in to a sealing contact against the cylinder wall. This arrangememt forms a simple and effective seal for high speed centrifuges, replacing more costly methods such as welding a closure in place.

  20. Centrifugal microfluidic platforms: advanced unit operations and applications.

    Science.gov (United States)

    Strohmeier, O; Keller, M; Schwemmer, F; Zehnle, S; Mark, D; von Stetten, F; Zengerle, R; Paust, N

    2015-10-07

    Centrifugal microfluidics has evolved into a mature technology. Several major diagnostic companies either have products on the market or are currently evaluating centrifugal microfluidics for product development. The fields of application are widespread and include clinical chemistry, immunodiagnostics and protein analysis, cell handling, molecular diagnostics, as well as food, water, and soil analysis. Nevertheless, new fluidic functions and applications that expand the possibilities of centrifugal microfluidics are being introduced at a high pace. In this review, we first present an up-to-date comprehensive overview of centrifugal microfluidic unit operations. Then, we introduce the term "process chain" to review how these unit operations can be combined for the automation of laboratory workflows. Such aggregation of basic functionalities enables efficient fluidic design at a higher level of integration. Furthermore, we analyze how novel, ground-breaking unit operations may foster the integration of more complex applications. Among these are the storage of pneumatic energy to realize complex switching sequences or to pump liquids radially inward, as well as the complete pre-storage and release of reagents. In this context, centrifugal microfluidics provides major advantages over other microfluidic actuation principles: the pulse-free inertial liquid propulsion provided by centrifugal microfluidics allows for closed fluidic systems that are free of any interfaces to external pumps. Processed volumes are easily scalable from nanoliters to milliliters. Volume forces can be adjusted by rotation and thus, even for very small volumes, surface forces may easily be overcome in the centrifugal gravity field which enables the efficient separation of nanoliter volumes from channels, chambers or sensor matrixes as well as the removal of any disturbing bubbles. In summary, centrifugal microfluidics takes advantage of a comprehensive set of fluidic unit operations such as

  1. Detection of circulating microparticles by flow cytometry: influence of centrifugation, filtration of buffer, and freezing.

    Science.gov (United States)

    Dey-Hazra, Emily; Hertel, Barbara; Kirsch, Torsten; Woywodt, Alexander; Lovric, Svjetlana; Haller, Hermann; Haubitz, Marion; Erdbruegger, Uta

    2010-12-06

    The clinical importance of microparticles resulting from vesiculation of platelets and other blood cells is increasingly recognized, although no standardized method exists for their measurement. Only a few studies have examined the analytical and preanalytical steps and variables affecting microparticle detection. We focused our analysis on microparticle detection by flow cytometry. The goal of our study was to analyze the effects of different centrifugation protocols looking at different durations of high and low centrifugation speeds. We also analyzed the effect of filtration of buffer and long-term freezing on microparticle quantification, as well as the role of Annexin V in the detection of microparticles. Absolute and platelet-derived microparticles were 10- to 15-fold higher using initial lower centrifugation speeds at 1500 × g compared with protocols using centrifugation speeds at 5000 × g (P centrifugation speeds. Filtration of buffer with a 0.2 μm filter reduced a significant amount of background noise. Storing samples for microparticle detection at -80°C decreased microparticle levels at days 28, 42, and 56 (P centrifugation speeds should be used to minimize contamination by smaller size platelets.

  2. 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

  3. Synchronization of Budding Yeast by Centrifugal Elutriation.

    Science.gov (United States)

    Rosebrock, Adam P

    2017-01-03

    In yeast, cell size is normally tightly linked to cell cycle progression. Centrifugal elutriation is a method that fractionates cells based on the physical properties of cell size-fluid drag and buoyant density. Using a specially modified centrifuge and rotor system, cells can be physically separated into one or more cohorts of similar size and therefore cell cycle position. Small G 1 daughters are collected first, followed by successively larger cells. Elutriated populations can be analyzed immediately or can be returned to medium and permitted to synchronously progress through the cell cycle. This protocol describes two different elutriation methods. In the first, one or more fractions of synchronized cells are obtained from an asynchronous starting population, reincubated, and followed prospectively across a time series. In the second, an asynchronous starting population is separated into multiple fractions of similarly sized cells, and each cohort of similarly sized cells can be analyzed separately without further growth. © 2017 Cold Spring Harbor Laboratory Press.

  4. Centrifugal separation for miscible solutions: Fundamentals and applications to separation of molten salt nuclear material

    International Nuclear Information System (INIS)

    Li Ning; Camassa, Roberto; Ecke, Robert E.; Venneri, Francesco

    1995-01-01

    We report on the physical separation of dilute solutions using centrifugal techniques. We use numerical simulations of the diffusion and sedimentation dynamics of centrifugation to model the approach to an equilibrium concentration profile. We verify experimentally the equilibrium profiles for aqueous solutions of different salts under rotation at 25000 rpm corresponding to centrifugal accelerations of about 57,000 g and 75,000 g in two different commercial centrifuges. These measurements provide ratios of sedimentation and diffusion coefficients. We show experimental results for the dynamics of separation that confirm the predictions of the theoretical model. We also measure the mass diffusion coefficient for several solutions. Although the relaxation to equilibrium is long, we have determined a method for efficiently extracting enriched components from a ternary mixture based on fast dynamics at early times. These dynamics are modeled in numerical simulations with realistic fluid parameters. Based on these studies we show that a multistage centrifugal separation process could provide efficient physical separation of actinides and fission products from a molten-salt solution in proposed transmutation/energy-production systems. We consider technical issues in the design of such a separation system

  5. Centrifugal separation for miscible solutions: Fundamentals and applications to separation of molten salt nuclear material

    International Nuclear Information System (INIS)

    Ning Li; Camassa, R.; Ecke, R.E.

    1995-01-01

    The authors report on the physical separation of dilute solutions using centrifugal techniques. They use numerical simulations of the diffusion and sedimentation dynamics of centrifugation to model the approach to an equilibrium concentration profile. They verify experimentally the equilibrium profiles for aqueous solutions of different salts under rotation at 25000 rpm corresponding to centrifugal accelerations of about 57,000 g and 75,000 g in two different commercial centrifuges. These measurements provide ratios of sedimentation and diffusion coefficients. The authors show experimental results for the dynamics of separation that confirm the predictions of the theoretical model. They also measure the mass diffusion coefficient for several solutions. Although the relaxation to equilibrium is long, they have determined a method for efficiently extracting enriched components from a ternary mixture based on fast dynamics at early times. These dynamics are modeled in numerical simulations with realistic fluid parameters. Based on these studies the authors show that a multistage centrifugal separation process could provide efficient physical separation of actinides and fission products from a molten-salt solution in proposed transmutation/energy-production systems. The authors consider technical issues in the design of such a separation system

  6. Centrifugal separation for miscible solutions: Fundamentals and applications to separation of molten salt nuclear material

    Energy Technology Data Exchange (ETDEWEB)

    Ning Li; Camassa, R.; Ecke, R.E. [Los Alamos National Laboratory, NM (United States)] [and others

    1995-10-01

    The authors report on the physical separation of dilute solutions using centrifugal techniques. They use numerical simulations of the diffusion and sedimentation dynamics of centrifugation to model the approach to an equilibrium concentration profile. They verify experimentally the equilibrium profiles for aqueous solutions of different salts under rotation at 25000 rpm corresponding to centrifugal accelerations of about 57,000 g and 75,000 g in two different commercial centrifuges. These measurements provide ratios of sedimentation and diffusion coefficients. The authors show experimental results for the dynamics of separation that confirm the predictions of the theoretical model. They also measure the mass diffusion coefficient for several solutions. Although the relaxation to equilibrium is long, they have determined a method for efficiently extracting enriched components from a ternary mixture based on fast dynamics at early times. These dynamics are modeled in numerical simulations with realistic fluid parameters. Based on these studies the authors show that a multistage centrifugal separation process could provide efficient physical separation of actinides and fission products from a molten-salt solution in proposed transmutation/energy-production systems. The authors consider technical issues in the design of such a separation system.

  7. Research on energy conversion mechanism of a screw centrifugal pump under the water

    International Nuclear Information System (INIS)

    Quan, H; Li, R N; Han, W; Cheng, X R; Shen, Z J; Su, Q M

    2013-01-01

    In order to research screw centrifugal pump impeller power capability and energy conversion mechanism, we used Navier-Stokes equation and standard k-ε equation turbulence model on the basis of the Euler equations to carry out screw centrifugal pump internal flow numerical simulation. This was explored by simulating specific design conditions; the medium is water, variation of speed and pressure of flow filed under the action of the impeller, and the screw centrifugal impeller shroud line and wheel line segment take monitoring sites. The monitoring points are between dynamic head and static head change to analyze the energy conversion capability along the impeller corners of screw centrifugal pump. The results show that the energy of fluid of the screw centrifugal pump is provided by spiral segment, the spiral segment in front of the impeller has played a multi-level role, it has significant reference value to research the energy conversion mechanism of screw centrifugal pump under solid-liquid two phase

  8. Numerical analysis on centrifugal compressor with membrane type dryer

    Science.gov (United States)

    Razali, M. A.; Zulkafli, M. F.; Mat Isa, N.; Subari, Z.

    2017-09-01

    Moisture content is a common phenomenon in industrial processes especially in oil and gas industries. This contaminant has a lot of disadvantages which can lead to mechanical failure DEC (Deposition, Erosion & Corrosion) problems. To overcome DEC problem, this study proposed to design a centrifugal compressor with a membrane type dryer to reduce moisture content of a gas. The effectiveness of such design has been analyzed in this study using Computational Fluid Dynamics (CFD) approach. Numerical scheme based on multiphase flow technique is used in ANSYS Fluent software to evaluate the moisture content of the gas. Through this technique, two kind of centrifugal compressor, with and without membrane type dryer has been tested. The results show that the effects of pressure on dew point temperature of the gas change the composition of its moisture content, where high value lead more condensation to occur. However, with the injection of cool dry gas through membrane type dryer in the centrifugal compressor, the pressure and temperature of moisture content as well as mass fraction of H2O in centrifugal compressor show significant reduction.

  9. Plasma rotation in plasma centrifuge with an annular gap

    International Nuclear Information System (INIS)

    Lee, H.Y.; Hong, S.H.

    1982-01-01

    The steady-state rotation of plasma centrifuge is theoretically analyzed to understand the physics of rotating plasma and its feasibility for isotope separation. The centriguge system under consideration consists of an annular gap between coaxial cylindrical anode and cathod in the presence of an externally-applied axial magnetic field. A problem for coupled partial differential equations describing centrifuge fields is formulated on the basis of the magnetohydrodynamic equations. Two-dimensional solutions are found analytically in the form of Fourier-Bessel series. The current density and velocity distributions are discussed in terms of the Hartmann number and the geometrical parameter of the system. At typical conditions, rotational speeds of the plasma up to the order of 10 4 m/sec are achievable, and increase either with increasing Hartmann number, or with increasing ratio of the axial length to the inner radius of the cylinder. In view of much higher speeds of rotation which can be achieved in plasma centrifuge, it is expected that its efficiency is superior to mechanically driven gas centrifuges. (Author)

  10. The effect of balance holes to centrifugal pump performance

    Science.gov (United States)

    Babayigit, O.; Ozgoren, M.; Aksoy, M. H.; Kocaaslan, O.

    2017-07-01

    The aim of this study is to analyze of a centrifugal pump with and without balance holes by using ANSYS-Fluent software. The pump used in the study is a commercial centrifugal pump consisting of two stages that is a model of Sempa Pump Company. Firstly, models of impeller, diffuser, suction and discharge sections of the centrifugal pump were separately drawn using Ansys and Solidworks software. Later, grid structures were generated on the flow volume of the pump. Turbulent flow volume was numerically solved by realizable k-є turbulence model. The flow analyses were focused on the centrifugal pump performance and the flow characteristics under different operational conditions with/without balance holes. Distributions of flow characteristics such as velocity and pressure distributions in the flow volume were also determined, numerically. The results of Computational Fluid Dynamics (CFD) with/without balance holes for the pump head and hydraulic efficiency on the design flow rate of 80 m3/h were found to be 81.5/91.3 m and 51.9/65.3%, respectively.

  11. Modeling of UF{sub 6} enrichment with gas centrifuges for nuclear safeguards activities

    Energy Technology Data Exchange (ETDEWEB)

    Mercurio, G.; Peerani, P.; Richir, P.; Janssens, W.; Eklund, G. [European Commission, Joint Research Centre, Institute for Transuranium Elements Via Fermi, 2749-TP181,20127 Ispra (Italy)

    2012-09-26

    The physical modeling of uranium isotopes ({sup 235}U, {sup 238}U) separation process by centrifugation of is a key aspect for predicting the nuclear fuel enrichment plant performances under surveillance by the Nuclear Safeguards Authorities. In this paper are illustrated some aspects of the modeling of fast centrifuges for UF{sub 6} gas enrichment and of a typical cascade enrichment plant with the Theoretical Centrifuge and Cascade Simulator (TCCS). The background theory for reproducing the flow field characteristics of a centrifuge is derived from the work of Cohen where the separation parameters are calculated using the solution of a differential enrichment equation. In our case we chose to solve the hydrodynamic equations for the motion of a compressible fluid in a centrifugal field using the Berman - Olander vertical velocity radial distribution and the solution was obtained using the Matlab software tool. The importance of a correct estimation of the centrifuge separation parameters at different flow regimes, lies in the possibility to estimate in a reliable way the U enrichment plant performances, once the separation external parameters are set (feed flow rate and feed, product and tails assays). Using the separation parameters of a single centrifuge allow to determine the performances of an entire cascade and, for this purpose; the software Simulink was used. The outputs of the calculation are the concentrations (assays) and the flow rates of the enriched (product) and depleted (tails) gas mixture. These models represent a valid additional tool, in order to verify the compliance of the U enrichment plant operator declarations with the 'on site' inspectors' measurements.

  12. Enrichment: centrifuge process

    International Nuclear Information System (INIS)

    Soubbaramayer.

    1989-01-01

    This short course is divided into three sections devoted respectively to the physics of the process, some practical problems raised by the design of a centrifuge and the present situation of centrifugation in the World. 31 figs., 18 refs

  13. A vibration model for centrifugal contactors

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, R.A.; Wasserman, M.O.; Wygmans, D.G.

    1992-11-01

    Using the transfer matrix method, we created the Excel worksheet ``Beam`` for analyzing vibrations in centrifugal contactors. With this worksheet, a user can calculate the first natural frequency of the motor/rotor system for a centrifugal contactor. We determined a typical value for the bearing stiffness (k{sub B}) of a motor after measuring the k{sub B} value for three different motors. The k{sub B} value is an important parameter in this model, but it is not normally available for motors. The assumptions that we made in creating the Beam worksheet were verified by comparing the calculated results with those from a VAX computer program, BEAM IV. The Beam worksheet was applied to several contactor designs for which we have experimental data and found to work well.

  14. Influences of centrifugation on cells and tissues in liposuction aspirates: optimized centrifugation for lipotransfer and cell isolation.

    Science.gov (United States)

    Kurita, Masakazu; Matsumoto, Daisuke; Shigeura, Tomokuni; Sato, Katsujiro; Gonda, Koichi; Harii, Kiyonori; Yoshimura, Kotaro

    2008-03-01

    Although injective autologous fat transplantation is one of the most attractive options for soft-tissue augmentation, problems such as unpredictability and fibrosis resulting from fat necrosis limit its universal acceptance. Centrifugation is one of most common methods for overcoming these difficulties. This study was performed to investigate quantitatively the effects of centrifugation on liposuction aspirates to optimize centrifugal conditions for fat transplantation and isolation of adipose-derived stem cells. Liposuction aspirates, obtained from eight healthy female donors, were either not centrifuged or centrifuged at 400, 700, 1200, 3000, or 4200 g for 3 minutes. The volumes of the oil, adipose, and fluid portions and numbers of blood cells and adipose-derived cells in each portion were examined. The processed adipose tissues (1 ml) were injected into athymic mice, and grafts were harvested and weighed at 4 weeks. Morphologic alterations were observed using light and scanning electron microscopy. Centrifugation concentrated adipose tissues and adipose-derived stem cells in the adipose portion and partly removed red blood cells from the adipose portion. Centrifugation at more than 3000 g significantly damaged adipose-derived stem cells. Centrifugation enhanced graft take per 1 ml centrifuged adipose but reduced calculated graft take per 1 ml adipose before centrifugation. Excessive centrifugation can destroy adipocytes and adipose-derived stem cells, but appropriate centrifugation concentrates them, resulting in enhanced graft take. The authors tentatively recommend 1200 g as an optimized centrifugal force for obtaining good short- and long-term results in adipose transplantation.

  15. Centrifuge apparatus

    Science.gov (United States)

    Sartory, Walter K.; Eveleigh, John W.

    1976-01-01

    A method and apparatus for operating a continuous flow blood separation centrifuge are provided. The hematocrit of the entrant whole blood is continuously maintained at an optimum constant value by the addition of plasma to the entrant blood. The hematocrit of the separated red cells is monitored to indicate the degree of separation taking place, thereby providing a basis for regulating the flow through the centrifuge.

  16. Quantification of platelets obtained by different centrifugation protocols in SHR rats.

    Science.gov (United States)

    Yazigi Junior, João Alberto; Dos Santos, João Baptista Gomes; Xavier, Bruno Rodrigues; Fernandes, Marcela; Valente, Sandra Gomes; Leite, Vilnei Mattiolli

    2015-01-01

    To quantify the platelet concentration in the blood of SHR rats, by means of different centrifugation protocols, and to evaluate what the most effective method for obtaining platelets is. We used 40 male rats of the isogenic SHR lineage. The animals were divided into three groups: control, using whole blood without centrifugation; single centrifugation, using whole blood subjected to a single centrifugation at 200 × g and 400 × g; and double centrifugation, using whole blood subjected one centrifugation at different rotations, followed by collection of whole plasma subjected to another centrifugation at different rotations: 200 × g + 200 × g; 200 × g + 400 × g; 200 × g + 800 × g; 400 × g + 400 × g; 400 × g + 800 × g. Samples of 3 ml of blood were drawn from each animal by means of cardiac puncture. The blood was stored in Vacutainer collection tubes containing 3.2% sodium citrate. The blood from the control group animals was analyzed without being subjected to centrifugation. After the blood from the other groups of animals had been subjected to centrifugation, the whole plasma was collected and subjected to platelet counting in the lower third of the sample. We obtained greatest platelet enrichment in the subgroup with two centrifugations comprising 400 × g for 10 min + 400 × g for 10 min, in which the mean platelet concentration was 11.30 times higher than that of the control group. It was possible to obtain a high platelet concentration using viable simple techniques, by means of centrifugation of whole blood and use of commonly used materials. The most effective method for obtaining platelet concentrate was found in samples subjected to two centrifugations.

  17. Simulations of overall flow in gas centrifuge considering feed jet

    International Nuclear Information System (INIS)

    He Liang; Jiang Dongjun; Ying Chuntong

    2010-01-01

    A coupled method for the numerical solution of the flow in rapidly rotating gas centrifuge was presented. An iteration process of DSMC and CFD was performed to analyze the overall flow in radial direction, in which DSMC was adopted to simulate the rarefied region, and CFD was adopted to the counter-current of gas centrifuge to discrete the model equations. It was applied to simulate the 2D symmetrical flow model considering the rarefied region with the feed jet flow. A series of illustrative numerical examples were given. The flow structures of the feed jet in the rarefied gas flow region were shown. The results suggest that DSMC CFD coupled method is competent to the simulations of overall flow in a gas centrifuge. (authors)

  18. Separation parameters of gas centrifuges

    International Nuclear Information System (INIS)

    May, W.G.

    1977-01-01

    Early work on development of the gas centrifuge for separation of uranium isotopes has recently been reviewed. Several configurations were investigated. The preferred configuration eventually turned out to be a countercurrent centrifuge. In this form, an internal circulation is set up, and as a consequence, light isotope concentrates at one end of the centrifuge, heavy isotope at the other. In many ways the effect resembles the separation obtained in packed columns in the chemical and petroleum industries. It is the purpose of this paper to develop this analogy between countercurrent gas centrifuges and packed towers and to illustrate its usefulness in understanding the separation process in the centrifuge. 8 figures

  19. New centrifugation blood culture device.

    Science.gov (United States)

    Dorn, G L; Smith, K

    1978-01-01

    A single-tube blood culture device designed for centrifugation in a tabletop centrifuge is described. Reconstruction experiments using 21 different organisms and human donor blood indicate that excellent recovery can be obtained by centrifugation for 30 min at 3,000 X g. PMID:342539

  20. 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.

  1. 76 FR 50767 - In the Matter of USEC Inc., American Centrifuge Lead Cascade Facility, and American Centrifuge...

    Science.gov (United States)

    2011-08-16

    ...; License Nos. SNM-7003, SNM-2011] In the Matter of USEC Inc., American Centrifuge Lead Cascade Facility, and American Centrifuge Plant; Order Extending the Date by Which the Direct Transfer of Licenses Is To... American Centrifuge Lead Cascade Facility (Lead Cascade) and American Centrifuge Plant (ACP), respectively...

  2. Unsteady flow measurements in centrifugal compressors

    International Nuclear Information System (INIS)

    Bammert, K.; Mobarak, A.; Rautenberg, M.

    1976-01-01

    Centrifugal compressors and blowers are often used for recycling the coolant gas in gas-cooled reactors. To achieve the required high pressure ratios, highly loaded centrifugal compressors are built. The paper deals with unsteady flow measurements on highly loaded centrifugal impellers. Measurements of the approaching flow have been done with hot wires. The method of measurement enabled us to get the velocity distribution across the pitch ahead of the inducer. The static pressure signals along the shroud line has been discussed on the basis of some theoretical considerations. Accordingly the form of flow in the impeller and the wave flow or separation zones in the impeller can now be better interpreted. The importance of the unsteady nature of the relative flow, especially at impeller exit, is clearly demonstrated. Measurements with high responsive total pressure probes in the vicinity of impeller exit and the subsequent calculations have shown, that the instantaneous energy transfer at a certain point after the impeller may differ by more than 30% from the Euler work. Lastly, unsteady pressure measurements along the shroud line have been performed during surge and rotating stall. The surge signal have been analyzed in more detail and the mechanism of flow rupture and pressure recovery during a surge cycle is thoroughly discussed. (orig.) [de

  3. High spatio-temporal resolution pollutant measurements of on-board vehicle emissions using ultra-fast response gas analyzers

    Directory of Open Access Journals (Sweden)

    M. Irwin

    2018-06-01

    Full Text Available Existing ultra-fast response engine exhaust emissions analyzers have been adapted for on-board vehicle use combined with GPS data. We present, for the first time, how high spatio-temporal resolution data products allow transient features associated with internal combustion engines to be examined in detail during on-road driving. Such data are both useful to examine the circumstances leading to high emissions, and reveals the accurate position of urban air quality hot spots as deposited by the candidate vehicle, useful for source attribution and dispersion modelling. The fast response time of the analyzers, which results in 100 Hz data, makes accurate time-alignment with the vehicle's engine control unit (ECU signals possible. This enables correlation with transient air fuel ratio, engine speed, load, and other engine parameters, which helps to explain the causes of the emissions spikes that portable emissions measurement systems (PEMS and conventional slow response analyzers would miss or smooth out due to mixing within their sampling systems. The data presented is from NO and NOx analyzers, but other fast analyzers (e.g. total hydrocarbons (THC, CO and CO2 can be used similarly. The high levels of NOx pollution associated with accelerating on entry ramps to motorways, driving over speed bumps, accelerating away from traffic lights, are explored in detail. The time-aligned ultra-fast analyzers offer unique insight allowing more accurate quantification and better interpretation of engine and driver activity and the associated emissions impact on local air quality.

  4. Outline of fast analyzer for MHD equilibrium 'FAME'

    International Nuclear Information System (INIS)

    Sakata, Shinya; Haginoya, Hirofumi; Tsuruoka, Takuya; Aoyagi, Tetsuo; Saito, Naoyuki; Harada, Hiroo; Tani, Keiji; Watanabe, Hideto.

    1994-03-01

    The FAME (Fast Analyzer for Magnetohydrodynamic (MHD) Equilibrium) system has been developed in order to provide more than 100 MHD equilibria in time series which are enough for the non-stationary analysis of the experimental data of JT-60 within about 20 minutes shot interval. The FAME is an MIMD type small scale parallel computer with 20 microprocessors which are connected by a multi-stage switching system. The maximum theoretical speed is 250 MFLOPS. For the software system of FAME, MHD equilibrium analysis code SELENE and its input data production code FBI are tuned up taking the parallel processing into consideration. Consequently, the computational performance of the FAME system becomes more than 7 times faster than the existing general purpose computer FACOM M780-10s. This report summarizes the outline of the FAME system including hardware, soft-ware and peripheral equipments. (author)

  5. Centrifuge design and development

    International Nuclear Information System (INIS)

    Edwards, T.T.; Holmes, M.D.

    1987-01-01

    BNFL has been enriching uranium on an industrial scale using the centrifuge process for over a decade. Together with its Urenco partners, a joint development programme has been and is being vigorously pursued to reduce specific costs, increase output and maintain competitiveness throughout the 1990s. The paper summarises the development of the centrifuge from its earliest concepts through to the centrifuges of today which are jointly designed by the Urenco partners. The potential for further development is also examined. (author)

  6. Clinostats and centrifuges: Their use, value, and limitations in gravitational biological research; Symposium, Washington, Oct. 19, 1991, Report

    Science.gov (United States)

    Halstead, Thora W. (Editor); Todd, Paul (Editor); Powers, Janet V. (Editor)

    1992-01-01

    The present volume addresses physical phenomena and effects associated with clinostat and centrifuge operations as well as their physiological effects. Particular attention is given to the simulation of the gravity conditions on the ground, the internal dynamics of slowly rotating biological systems, and qualitative and quantitative aspects of the fast-rotating clinostat as a research tool. Also discussed are the development and use of centrifuges in gravitational biology, the use of centrifuges in plant gravitational biology and a comparison of ground-based and flight experiment results, the ability of clinostat to mimic the effect of microgravity on plant cells and organs, and the impact of altered gravity conditions on early EGF-induced signal transduction in human epidermal A431 cells.

  7. Vacuum chamber-free centrifuge with magnetic bearings.

    Science.gov (United States)

    Park, Cheol Hoon; Kim, Soohyun; Kim, Kyung-Soo

    2013-09-01

    Centrifuges are devices that separate particles of different densities and sizes through the application of a centrifugal force. If a centrifuge could be operated under atmospheric conditions, all vacuum-related components such as the vacuum chamber, vacuum pump, diffusion pump, and sealing could be removed from a conventional centrifuge system. The design and manufacturing procedure for centrifuges could then be greatly simplified to facilitate the production of lightweight centrifuge systems of smaller volume. Furthermore, the maintenance costs incurred owing to wear and tear due to conventional ball bearings would be eliminated. In this study, we describe a novel vacuum chamber-free centrifuge supported by magnetic bearings. We demonstrate the feasibility of the vacuum chamber-free centrifuge by presenting experimental results that verify its high-speed support capability and motoring power capacity.

  8. Flow control arrangements for centrifuges

    International Nuclear Information System (INIS)

    Alderton, G.W.; Davidge, P.C.

    1983-01-01

    In a centrifuge plant for the separation of uranium isotopes, when a centrifuge machine breaks down, light gas is produced. This gas can cause adjacent machines to break down, so propagating the fault. The present invention provides flow control arrangements in gas pipes to the centrifuge, whereby sudden egress of gas from a failed machine is inhibited. (author)

  9. Evaluation of enrichment by centrifugal separation: the future of the centrifugal-separation method

    International Nuclear Information System (INIS)

    Kanagawa, A.

    A gas centrifuge plant for uranium enrichment is considered from the point of view of economic competition with other methods. Characteristics of the method are presented including: energy efficiency, the cascade, the separation coefficient, the equilibrium separation process, and capability as centrifugal pump. The structure of an individual gas centrifuge separator is described including the rotating cylinder, mechanisms for gas injection and extraction, mechanisms for counter-streaming of gas, the axle holder mechanism, the gas sealing mechanism, and the driving mechanism. (U.S.)

  10. Centrifugal Compressor Aeroelastic Analysis Code

    Science.gov (United States)

    Keith, Theo G., Jr.; Srivastava, Rakesh

    2002-01-01

    Centrifugal compressors are very widely used in the turbomachine industry where low mass flow rates are required. Gas turbine engines for tanks, rotorcraft and small jets rely extensively on centrifugal compressors for rugged and compact design. These compressors experience problems related with unsteadiness of flowfields, such as stall flutter, separation at the trailing edge over diffuser guide vanes, tip vortex unsteadiness, etc., leading to rotating stall and surge. Considerable interest exists in small gas turbine engine manufacturers to understand and eventually eliminate the problems related to centrifugal compressors. The geometric complexity of centrifugal compressor blades and the twisting of the blade passages makes the linear methods inapplicable. Advanced computational fluid dynamics (CFD) methods are needed for accurate unsteady aerodynamic and aeroelastic analysis of centrifugal compressors. Most of the current day industrial turbomachines and small aircraft engines are designed with a centrifugal compressor. With such a large customer base and NASA Glenn Research Center being, the lead center for turbomachines, it is important that adequate emphasis be placed on this area as well. Currently, this activity is not supported under any project at NASA Glenn.

  11. Aerodynamic Optimization Design of a Multistage Centrifugal Steam Turbine and Its Off-Design Performance Analysis

    Directory of Open Access Journals (Sweden)

    Hui Li

    2017-01-01

    Full Text Available Centrifugal turbine which has less land occupation, simple structure, and high aerodynamic efficiency is suitable to be used as small to medium size steam turbines or waste heat recovery plant. In this paper, one-dimensional design of a multistage centrifugal steam turbine was performed by using in-house one-dimensional aerodynamic design program. In addition, three-dimensional numerical simulation was also performed in order to analyze design and off-design aerodynamic performance of the proposed centrifugal steam turbine. The results exhibit reasonable flow field and smooth streamline; the aerodynamic performance of the designed turbine meets our initial expectations. These results indicate that the one-dimensional aerodynamic design program is reliable and effective. The off-design aerodynamic performance of centrifugal steam turbine was analyzed, and the results show that the mass flow increases with the decrease of the pressure ratio at a constant speed, until the critical mass flow is reached. The efficiency curve with the pressure ratio has an optimum efficiency point. And the pressure ratio of the optimum efficiency agrees well with that of the one-dimensional design. The shaft power decreases as the pressure ratio increases at a constant speed. Overall, the centrifugal turbine has a wide range and good off-design aerodynamic performance.

  12. The magnetic centrifugal mass filter

    International Nuclear Information System (INIS)

    Fetterman, Abraham J.; Fisch, Nathaniel J.

    2011-01-01

    Mass filters using rotating plasmas have been considered for separating nuclear waste and spent nuclear fuel. We propose a new mass filter that utilizes centrifugal and magnetic confinement of ions in a way similar to the asymmetric centrifugal trap. This magnetic centrifugal mass filter is shown to be more proliferation resistant than present technology. This filter is collisional and produces well confined output streams, among other advantages.

  13. The magnetic centrifugal mass filter

    Energy Technology Data Exchange (ETDEWEB)

    Fetterman, Abraham J.; Fisch, Nathaniel J. [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08540 (United States)

    2011-09-15

    Mass filters using rotating plasmas have been considered for separating nuclear waste and spent nuclear fuel. We propose a new mass filter that utilizes centrifugal and magnetic confinement of ions in a way similar to the asymmetric centrifugal trap. This magnetic centrifugal mass filter is shown to be more proliferation resistant than present technology. This filter is collisional and produces well confined output streams, among other advantages.

  14. Numerical modeling and optimization of the Iguassu gas centrifuge

    Science.gov (United States)

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

    2017-07-01

    The full procedure of the numerical calculation of the optimized parameters of the Iguassu gas centrifuge (GC) is under discussion. The procedure consists of a few steps. On the first step the problem of a hydrodynamical flow of the gas in the rotating rotor of the GC is solved numerically. On the second step the problem of diffusion of the binary mixture of isotopes is solved. The separation power of the gas centrifuge is calculated after that. On the last step the time consuming procedure of optimization of the GC is performed providing us the maximum of the separation power. The optimization is based on the BOBYQA method exploring the results of numerical simulations of the hydrodynamics and diffusion of the mixture of isotopes. Fast convergence of calculations is achieved due to exploring of a direct solver at the solution of the hydrodynamical and diffusion parts of the problem. Optimized separative power and optimal internal parameters of the Iguassu GC with 1 m rotor were calculated using the developed approach. Optimization procedure converges in 45 iterations taking 811 minutes.

  15. Theoretical investigations on plasma centrifuges

    International Nuclear Information System (INIS)

    Hong, S.H.

    1978-01-01

    The theoretical analysis of the steady-state dynamics of plasma centrifuges is dealt with to understand the physics of rotating plasmas and their feasibility for isotope separation. The centrifuge systems under consideration employ cylindrical gas discharge chambers with externally-applied axial magnetic fields. The cathode and anode are symmetric about the cylinder axis and arranged in such a way for each system, i.e., (1) two ring electrodes of different radii in the chamber end plates or (2) two ring electrodes embedded in the mantle of the cylinder. They produce converging and/or diverging current density field lines, which intersect the external magnetic field under a nonvanishing angle. The associated Lorentz forces set the plasma, which is produced through an electrical discharge, into rotation around the cylinder axis. Three boundary-value problems for the coupled partial differential equations of the centrifuge fields are formulated, respectively, on the basis of the magnetogasdynamic equations. The electric field, electrostatic potential, current density, induced magnetic field, and velocity distributions are discussed in terms of the Hartmann number, the Hall coefficient, and the magnetic Reynolds number. The plasma centrifuge analyses presented show that the speeds of plasma rotation up to the order of 10 4 m/sec are achievable at typical conditions. The associated centrifugal forces produce a significant spatial isotope separation, which is somewhat reduced in the viscous boundary layers at the centrifuge walls. The speeds of plasma rotation increase with increasing Hartmann number and Hall coefficient. For small Hall coefficient, the induced azimuthal magnetic field does not affect the plasma rotation. For large volumes of rotating isotope mixtures, a multidischarge centrifuge can be constructed by setting up a large number of centrifuge systems in series

  16. Analysis of heat transfer in a centrifugal film evaporator

    NARCIS (Netherlands)

    Bruin, S.

    1970-01-01

    Heat transfer in a centrifugal film evaporator with a conical heating surface is analyzed. Two regions of transfer can be distinguished: an entrance region, where the temp. profile in the film develops, and an evapn. region, where \\"surface evapn.\\" takes place. Relations are derived for liq.-film

  17. 21 CFR 864.5350 - Microsedimentation centrifuge.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Microsedimentation centrifuge. 864.5350 Section 864.5350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... § 864.5350 Microsedimentation centrifuge. (a) Identification. A microsedimentation centrifuge is a...

  18. Uranium enrichment by gas centrifuge

    International Nuclear Information System (INIS)

    Heriot, I.D.

    1988-01-01

    After recalling the physical principles and the techniques of centrifuge enrichment the report describes the centrifuge enrichment programmes of the various countries concerned and compares this technology with other enrichment technologies like gaseous diffusion, laser, aerodynamic devices and chemical processes. The centrifuge enrichment process is said to be able to replace with advantage the existing enrichment facilities in the short and medium term. Future prospects of the process are also described, like recycled uranium enrichment and economic improvements; research and development needs to achieve the economic prospects are also indicated. Finally the report takes note of the positive aspect of centrifuge enrichment as far as safeguards and nuclear safety are concerned. 27 figs, 113 refs

  19. Optimization of flavanones extraction by modulating differential solvent densities and centrifuge temperatures.

    Science.gov (United States)

    Chebrolu, Kranthi K; Jayaprakasha, G K; Jifon, J; Patil, Bhimanagouda S

    2011-07-15

    Understanding the factors influencing flavonone extraction is critical for the knowledge in sample preparation. The present study was focused on the extraction parameters such as solvent, heat, centrifugal speed, centrifuge temperature, sample to solvent ratio, extraction cycles, sonication time, microwave time and their interactions on sample preparation. Flavanones were analyzed in a high performance liquid chromatography (HPLC) and later identified by liquid chromatography and mass spectrometry (LC-MS). The five flavanones were eluted by a binary mobile phase with 0.03% phosphoric acid and acetonitrile in 20 min and detected at 280 nm, and later identified by mass spectral analysis. Dimethylsulfoxide (DMSO) and dimethyl formamide (DMF) had optimum extraction levels of narirutin, naringin, neohesperidin, didymin and poncirin compared to methanol (MeOH), ethanol (EtOH) and acetonitrile (ACN). Centrifuge temperature had a significant effect on flavanone distribution in the extracts. The DMSO and DMF extracts had homogeneous distribution of flavanones compared to MeOH, EtOH and ACN after centrifugation. Furthermore, ACN showed clear phase separation due to differential densities in the extracts after centrifugation. The number of extraction cycles significantly increased the flavanone levels during extraction. Modulating the sample to solvent ratio increased naringin quantity in the extracts. Current research provides critical information on the role of centrifuge temperature, extraction solvent and their interactions on flavanone distribution in extracts. Published by Elsevier B.V.

  20. CFD simulation of centrifugal cells washers.

    Science.gov (United States)

    Kellet, Beth E; Binbing, Han; Dandy, David S; Wickramasinghe, S Ranil

    2004-01-01

    The feasibility of using computational fluid dynamics to guide the design of better centrifuges for processing shed blood is explored here. The velocity field and the rate of protein removal from the shed blood have been studied. The results indicate that computational fluid dynamics could help screen preliminary centrifuge bowl designs thus reducing the number of initial experimental tests required when developing new centrifuge bowls. Though the focus of this work is on washing shed blood the methods developed here are applicable to the design of centrifuge bowls for other blood processing applications.

  1. Active unsteady aerodynamic suppression of rotating stall in an incompressible flow centrifugal compressor with vaned diffuser

    Science.gov (United States)

    Lawless, Patrick B.; Fleeter, Sanford

    1991-01-01

    A mathematical model is developed to analyze the suppression of rotating stall in an incompressible flow centrifugal compressor with a vaned diffuser, thereby addressing the important need for centrifugal compressor rotating stall and surge control. In this model, the precursor to to instability is a weak rotating potential velocity perturbation in the inlet flow field that eventually develops into a finite disturbance. To suppress the growth of this potential disturbance, a rotating control vortical velocity disturbance is introduced into the impeller inlet flow. The effectiveness of this control is analyzed by matching the perturbation pressure in the compressor inlet and exit flow fields with a model for the unsteady behavior of the compressor. To demonstrate instability control, this model is then used to predict the control effectiveness for centrifugal compressor geometries based on a low speed research centrifugal compressor. These results indicate that reductions of 10 to 15 percent in the mean inlet flow coefficient at instability are possible with control waveforms of half the magnitude of the total disturbance at the inlet.

  2. Progress in ultra-centrifuge enrichment technology

    International Nuclear Information System (INIS)

    Paul Dawson

    2006-01-01

    Urenco have undertaken a continuous development programme in centrifuge technology for over 35 years. This has seen development from sub-critical machines in the mid 1970's through to the company's world leading TC12 supercritical centrifuge, which has been deployed on a large-scale basis over the last decade. The latest centrifuge to emerge from this programme is Urenco's sixth generation centrifuge, the TC21, which will be commercially deployed from mid-2007 onwards. In recent times Urenco has vested its centrifuge technology in Enrichment Technology Company (ETC) as a vehicle to enable the use of this advanced technology by other operators for commercial purposes. This paper reviews why Urenco and ETC believe this technology represents the best choice for creating new global commercial enrichment capacity and its future development prospects. (author)

  3. 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.

  4. Polybutadiene latex particle size distribution analysis utilizing a disk centrifuge

    NARCIS (Netherlands)

    Verdurmen, E.M.F.J.; Albers, J.G.; German, A.L.

    1994-01-01

    Polybutadiene (I) latexes prepd. by emulsifier-free emulsion polymn. and having particle diam. 50-300 nm for both unimodal and bimodal particles size distributions were analyzed by the line-start (LIST) method in a Brookhaven disk centrifuge photosedimentometer. A special spin fluid was designed to

  5. Research on the effect of wear-ring clearances to the axial and radial force of a centrifugal pump

    International Nuclear Information System (INIS)

    Zhao, W G; Qi, C X; Li, Y B; He, M Y

    2013-01-01

    Varying of the wear-ring clearance not only has a distinct effect on the volumetric loss of the centrifugal pump, but also on the performance of the centrifugal pump including the axial and radial forces. Comparing with the experimental studies, numerical simulation methods have some special advantages, such as the low cost, fast and high efficiency, and convenient to get the detailed structure of the internal flow characteristics, so it has been widely used in the fluid machinery study in recent years. In order to study the effect of wear-ring clearance on the force performance of the centrifugal pump, based on the Reynolds Time-Averaged N-S equations and RNG k-ε turbulence model, a centrifugal pump with three variable styles of the wear-rings was simulated: Only the clearance of the front wear-ring was changed, only the clearance of the back wear-ring was changed and both were changed. Comparing with the experiment, numerical results show a good agreement. In the three changing styles of the clearance, the variable of the clearance of front wear-ring has the most influence on the axial force of the centrifugal pump, while has tiny effect on the radial force for all the conditions

  6. Centrifuge Health Monitoring of the 50gTon beam centrifuge at the University of Sheffield

    OpenAIRE

    Cox, C.M.; Black, J.A.; Hakhamanshi, M.; Baker, N.

    2016-01-01

    In order to fully understand scientific test data it is crucial that we first understand the back-ground centrifuge operational environment and its variation with time and centrifugal acceleration. For exam-ple, changes in ambient air temperature or relative humidity in the centrifuge chamber during operation can have a significant impact on the evaporation levels of water from the surface of a clay model. It is vital to un-derstand these temporal changes in order to mitigate drying out of th...

  7. 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

  8. The Advanced Gas Centrifuge program

    International Nuclear Information System (INIS)

    Riepe, R.

    1984-01-01

    Although the gas centrifuge process for uranium enrichment is often referred to as a ''new technology,'' it has been under development for approximately 25 years to bring it to its current state of deployment. Centrifuges are now being installed in a new gas centrifuge enrichment plant (GCEP) at Portsmouth, Ohio. The objective of this new plant was to provide additional U.S. uranium enrichment capacity at a production cost comparable to the U.S. diffusion process but requiring much less power per separative work unit (SWU) produced. The current, commercial scale centrifuge technology being installed meets that objective. The objective for new U.S. enrichment capacity has changed. The objective is not to provide more SWUs but to provide cheaper SWUs. The objective is to make the U.S. uranium enrichment enterprise competitive on the international market. Where the U.S. at one time supplied virtually all of the free world SWU demand, the U.S. market share has now dropped to approximately 35% of the foreign free world market. The Advanced Gas Centrifuge (AGC) program provides an avenue for making the U.S. the economically attractive, reliable enrichment supplier

  9. Extraction of soil solution by drainage centrifugation-effects of centrifugal force and time of centrifugation on soil moisture recovery and solute concentration in soil moisture of loess subsoils.

    Science.gov (United States)

    Fraters, Dico; Boom, Gerard J F L; Boumans, Leo J M; de Weerd, Henk; Wolters, Monique

    2017-02-01

    The solute concentration in the subsoil beneath the root zone is an important parameter for leaching assessment. Drainage centrifugation is considered a simple and straightforward method of determining soil solution chemistry. Although several studies have been carried out to determine whether this method is robust, hardly any results are available for loess subsoils. To study the effect of centrifugation conditions on soil moisture recovery and solute concentration, we sampled the subsoil (1.5-3.0 m depth) at commercial farms in the loess region of the Netherlands. The effect of time (20, 35, 60, 120 and 240 min) on recovery was studied at two levels of the relative centrifugal force (733 and 6597g). The effect of force on recovery was studied by centrifugation for 35 min at 117, 264, 733, 2932, 6597 and 14,191g. All soil moisture samples were chemically analysed. This study shows that drainage centrifugation offers a robust, reproducible and standardised way for determining solute concentrations in mobile soil moisture in silt loam subsoils. The centrifugal force, rather than centrifugation time, has a major effect on recovery. The maximum recovery for silt loams at field capacity is about 40%. Concentrations of most solutes are fairly constant with an increasing recovery, as most solutes, including nitrate, did not show a change in concentration with an increasing recovery.

  10. Centrifuge facilities at Technical University of Denmark

    DEFF Research Database (Denmark)

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

    2008-01-01

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

  11. Impact of sample processing on the measurement of circulating microparticles: storage and centrifugation parameters.

    Science.gov (United States)

    Vila-Liante, Virtudes; Sánchez-López, Verónica; Martínez-Sales, Vicenta; Ramón-Nuñez, Luis A; Arellano-Orden, Elena; Cano-Ruiz, Alejandra; Rodríguez-Martorell, Francisco J; Gao, Lin; Otero-Candelera, Remedios

    2016-11-01

    Microparticles (MPs) have been shown to be markers of cellular activation and interactions. Pre-analytical conditions such as the centrifugation protocol and sample storage conditions represent an important source of variability in determining MPs values. The objectives of this study were to evaluate the influence of sample storage conditions and centrifugation speed and temperature on the determination of MPs in plasma. Citrate-anticoagulated blood samples obtained from 21 healthy subjects were centrifuged under four different protocols involving different speeds (2500 g or 1500 g) and temperatures (4 °C or 20 °C) to isolate platelet-poor plasma (PPP). The number of MPs in fresh and frozen-thawed PPP were analyzed by flow cytometry, and MPs-mediated procoagulant activity was determined by a thrombin generation test and phospholipid-dependent procoagulant tests. The number of MPs and their procoagulant activity were affected by freeze-thaw cycling and centrifugation speed but not by centrifugation temperature. Sample freezing increased MPs number (six-fold) and thrombin generation (four-fold), and decreased clotting time (two-fold). Low centrifugation speed caused an increase in MPs number and a parallel increase in MP-mediated procoagulant activity. Sample storage conditions and centrifugation speed are important processing conditions affecting MPs number and activity. Before any study, the protocol for MPs isolation should be optimized to ensure a reliable characterization of MPs, which could provide important information for diagnostic purposes and for understanding the pathogenesis of diseases.

  12. Numerical Optimization of Impeller for Backward-Curved Centrifugal Fan by Response Surface Methodology (RSM)

    OpenAIRE

    Fannian Meng; Quanlin Dong; Yan Wang; Pengfei Wang; Chunxi Zhang

    2013-01-01

    A numerical optimum study on three-dimensional unsteady viscous flow in a centrifugal fan with backward-curved blades was performed. The influence of the inlet angle, the outlet blade angle and blade number on aerodynamic performance of the centrifugal fan was analyzed concerning the whole impeller-volute configuration. Response Surface Methodology (RSM) based on a three-level, three -variable Box-Behnken Design (BBD) was used to evaluate the interactive effects of factors such as inlet blade...

  13. Some engineering considerations when designing centrifuge enrichment plants

    International Nuclear Information System (INIS)

    Edwards, T.T.

    1982-01-01

    A review is given of the three main areas where flexibility is needed in the design of centrifuge enrichment plants. These are: the need to cope with market requirements, the limitations imposed by currently available centrifuges and ever advancing centrifuge technology. Details of BNFL's experience with centrifuge enrichment at Capenhurst are presented. (U.K.)

  14. Isolating peripheral lymphocytes by density gradient centrifugation and magnetic cell sorting.

    Science.gov (United States)

    Brosseron, Frederic; Marcus, Katrin; May, Caroline

    2015-01-01

    Combining density gradient centrifugation with magnetic cell sorting provides a powerful tool to isolate blood cells with high reproducibility, yield, and purity. It also allows for subsequent separation of multiple cell types, resulting in the possibility to analyze different purified fractions from one donor's sample. The centrifugation step divides whole blood into peripheral blood mononuclear cells (PBMC), erythrocytes, and platelet-rich plasma. In the following, lymphocyte subtypes can be consecutively isolated from the PBMC fraction. This chapter describes enrichment of erythrocytes, CD14-positive monocytes and CD3-positive T lymphocytes. Alternatively, other cell types can be targeted by using magnetic beads specific for the desired subpopulation.

  15. Centrifuge treatment of coal tar

    Energy Technology Data Exchange (ETDEWEB)

    L.A. Kazak; V.Z. Kaidalov; L.F. Syrova; O.S. Miroshnichenko; A.S. Minakov [Giprokoks, the State Institute for the Design of Coke-Industry Enterprises, Kharkov (Ukraine)

    2009-07-15

    New technology is required for the removal of water and heavy fractions from regular coal tar. Centrifuges offer the best option. Purification of coal tar by means of centrifuges at OAO NLMK permits the production of pitch coke or electrode pitch that complies with current standards.

  16. Centrifuges and inertial shear forces

    NARCIS (Netherlands)

    Loon, van J.J.W.A.; Folgering, H.T.E.; Bouten, C.V.C.; Smit, T.H.

    2004-01-01

    Centrifuges are often used in biological studies for 1xg control samples in space flight microgravity experiments as well as in ground based research. Using centrifugation as a tool to generate an Earth like acceleration introduces unwanted inertial shear forces to the sample. Depending on the

  17. Design of Structural Parameters for Centrifugal Elevator Overspeed Governors

    Directory of Open Access Journals (Sweden)

    Song Yunpu

    2014-01-01

    Full Text Available As an important part of overspeed and fail-safe protection for elevators, the centrifugal elevator overspeed governor is a device for limiting overspeed of elevator cars. This paper researches on the vibration of the centrifugal block, which plays a key role in the performance of this overspeed governor. By performing dynamics analysis on the centrifugal block, the differential equation on the vibration of the centrifugal block is established. Based on this, the paper performs simulation analysis on the influence of systematic parameters such as the speed of the overspeed governor sheave, the mass of centrifugal block, the turning radius of the centrifugal block, the position where the spring acts, and the stiffness of the centrifugal block spring, on the vibration of the centrifugal block, and finds out their specific influence relationship.

  18. Theoretical considerations in solid bowl centrifugation

    International Nuclear Information System (INIS)

    Hamilton, R.T.

    1979-01-01

    A combination of literature survey and independent analysis determined three relationships for the prediction of the critical (or minimum recoverable) particle size in a solid bowl centrifuge. The relationships were derived based on three different theories of fluid behavior within the centrifuge; (1) laminar film flow (laminar film model), (2) plug flow (Sharples Model), and parabolic flow (modified Sharples Model). The critical particle size for the centrifuge used in Cs-PTA recovery in the CAW process predicted by the three relationships range from 0.19 to 0.34 μm (1 μm = 10 -6 m). The laminar film model gives the most conservative estimate of critical particle size (0.34 μm) and the resulting relationship is recommended for use to predict solid bowl centrifuge performance. Three correction factors are incorporated into the predictive equations to account for the effects of fluid turbulence near the centrifuge feed point, fluid lag and hindered settling. Of these factors, turbulence near the feed point (which is accounted for by using an effective centrifuge length) has the greatest impact, increasing the predicted critical particle size by 15%, while the combination of fluid lag and hindered settling factors increase the recoverable particle size by 4%. The overall effect of the correction factors is an approximately 20% decrease in centrifuge effectivity. The fraction of solids smaller than the critical size range has not been reliably determined for laboratory or plant prepared Cs-PTA. In addition, the density of Cs-PTA crystals is reported to vary from 3.2 to 12 grams per cubic centimeter

  19. Investigation on steady and unsteady performance of a SCO2 centrifugal compressor with splitters

    Directory of Open Access Journals (Sweden)

    Guo Ding

    2017-01-01

    Full Text Available Supercritical carbon dioxide (SCO2 is widely concerned with its excellent physical properties. Its high density helps to achieve a compact mechanical structure, especially in all kinds of turbomachinery. In this paper, a SCO2 centrifugal compressor with splitter blades is displayed and numerically investigated. A thorough numerical analysis of the steady and unsteady performance of this SCO2 centrifugal compressor is performed in ANSYS-CFX with SST turbulence model. Streamlines, pressure and temperature under steady- and unsteady-state are compared and analyzed. Moreover, the trans-critical phenomenon at the leading edge of the rotor blade and the aerodynamic performance are covered. The results in this paper provide the foundation for the design and numerical investigation of SCO2 centrifugal compressors.

  20. Aerodynamic Optimization Design of a Multistage Centrifugal Steam Turbine and Its Off-Design Performance Analysis

    OpenAIRE

    Hui Li; Dian-Gui Huang

    2017-01-01

    Centrifugal turbine which has less land occupation, simple structure, and high aerodynamic efficiency is suitable to be used as small to medium size steam turbines or waste heat recovery plant. In this paper, one-dimensional design of a multistage centrifugal steam turbine was performed by using in-house one-dimensional aerodynamic design program. In addition, three-dimensional numerical simulation was also performed in order to analyze design and off-design aerodynamic performance of the pro...

  1. Compatibility of the Space Station Freedom life sciences research centrifuge with microgravity requirements

    Science.gov (United States)

    Hasha, Martin D.

    1990-01-01

    NASA is developing a Life Sciences Centrifuge Facility for Space Station Freedom. In includes a 2.5-meter artificial gravity Bioresearch Centrifuge (BC), which is perhaps the most critical single element in the life sciences space research program. It rotates continuously at precise selectable rates, and utilizes advanced reliable technologies to reduce vibrations. Three disturbance types are analyzed using a current Space Station Freedom dynamic model in the 0.0 to 5.0 Hz range: sinusoidal, random, and transient. Results show that with proper selection of proven design techniques, BC vibrations are compatible with requirements.

  2. Weak rotating flow disturbances in a centrifugal compressor with a vaneless diffuser

    Science.gov (United States)

    Moore, F. K.

    1988-01-01

    A theory is presented to predict the occurrence of weak rotating waves in a centrifugal compression system with a vaneless diffuser. As in a previous study of axial systems, an undisturbed performance characteristic is assumed known. Following an inviscid analysis of the diffuser flow, conditions for a neutral rotating disturbance are found. The solution is shown to have two branches; one with fast rotation, the other with very slow rotation. The slow branch includes a dense set of resonant solutions. The resonance is a feature of the diffuser flow, and therefore such disturbances must be expected at the various resonant flow coefficients regardless of the compressor characteristic. Slow solutions seem limited to flow coefficients less than about 0.3, where third and fourth harmonics appear. Fast waves seem limited to a first harmonic. These fast and slow waves are described, and effects of diffuser-wall convergence, backward blade angles, and partial recovery of exit velocity head are assessed.

  3. Gas dynamics in strong centrifugal fields

    OpenAIRE

    Bogovalov, S. V.; Kislov, V. A.; Tronin, I. V.

    2017-01-01

    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 $10^6$g. 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 wa...

  4. Dual centrifugation - A new technique for nanomilling of poorly soluble drugs and formulation screening by an DoE-approach.

    Science.gov (United States)

    Hagedorn, Martin; Bögershausen, Ansgar; Rischer, Matthias; Schubert, Rolf; Massing, Ulrich

    2017-09-15

    The development of nanosuspensions of poorly soluble APIs takes a lot of time and high amount of active material is needed. In this publication the use of dual centrifugation (DC) for an effective and rapid API-nanomilling is described for the first time. DC differs from normal centrifugation by an additional rotation of the samples during centrifugation, resulting in a very fast and powerful movement of the samples inside the vials, which - in combination with milling beads - result in effective milling. DC-nanomilling was compared to conventional wet ball milling and results in same or even smaller particle sizes. Also drug concentrations up to 40% can be processed. The process is fast (typical 90min) and the temperature can be controlled. DC-nanomilling appears to be very gentle, experiments showed no change of the crystal structure during milling. Since batch sizes are very small (100-1000mg) and since 40 sample vials can be processed in parallel, DC is ideal for the screening of suitable polymer/surfactant combinations. Fenofibrate was used to investigate DC-nanomilling for formulation screening by applying a DoE-approach. The presented data also show that the results of DC-nanomilling experiments are highly comparable to the results obtained by common agitator mills. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Liquid centrifugation for nuclear waste partitioning

    International Nuclear Information System (INIS)

    Bowman, C.D.

    1992-01-01

    The performance of liquid centrifugation for nuclear waste partitioning is examined for the Accelerator Transmutation of Waste Program currently under study at the Los Alamos National Laboratory. Centrifugation might have application for the separation of the LiF-BeF 2 salt from heavier radioactive materials fission product and actinides in the separation of fission product from actinides, in the isotope separation of fission-product cesium before transmutation of the 137 Cs and 135 Cs, and in the removal of spallation product from the liquid lead target. It is found that useful chemical separations should be possible using existing materials for the centrifuge construction for all four cases with the actinide fraction in fission product perhaps as low as 1 part in 10 7 and the fraction of 137 CS in 133 Cs being as low as a few parts in 10 5 . A centrifuge cascade has the advantage that it can be assembled and operated as a completely closed system without a waste stream except that associated with maintenance or replacement of centrifuge components

  6. Radial loads and axial thrusts on centrifugal pumps

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    The proceedings of a seminar organised by the Power Industries Division of the IMechE are presented in this text. Complete contents: Review of parameters influencing hydraulic forces on centrifugal impellers; The effect of fluid forces at various operation conditions on the vibrations of vertical turbine pumps; A review of the pump rotor axial equilibrium problem - some case studies; Dynamic hydraulic loading on a centrifugal pump impeller; Experimental research on axial thrust loads of double suction centrifugal pumps; A comparison of pressure distribution and radial loads on centrifugal pumps; A theoretical and experimental investigation of axial thrusts within a multi-stage centrifugal pump

  7. Study on cavitation in centrifugal sodium pumps for FBTR and PFBR

    International Nuclear Information System (INIS)

    Rao, A.S.L.K.; Prabhakar, R.; Prakash, V.; Paranjpe, S.R.

    2002-01-01

    Fast Breeder Test Reactor (FBTR) which is expected to become critical shortly is a loop type reactor of 40 MW thermal capacity and has two primary and two secondary centrifugal pumps for heat removal. During the initial periods of reactor operation, the steam generator is bypassed and the secondary sodium pumps are required to operate at flows less than that at best efficiency point. This paper deals with the cavitation problems associated with operation at partial f lows, theoretical estimations and experimental cavitation measurements carried out on FBTR secondary sodium pumps. These investigations revealed that operation of FBTR pumps at this off design condition is free from cavitation damage. Cavitation experiments on a model pump for the development of large sodium pumps for a 500 MWe Prototype Fast Breeder Reactor (PFBR) are described in this paper

  8. Centrifugal separator cascade connected in zigzag manner

    International Nuclear Information System (INIS)

    Kai, Tsunetoshi; Inoue, Yoshiya; Oya, Akio; Nagakura, Masaaki.

    1974-01-01

    Object: To effectively accommodate centrifugal separators of the entire cascade within the available space in a plant by freely selecting perpendicular direction of connection of the centrifugal separator. Structure: Centrifugal separators are connected in zigzag fashion by using a single header for each stage so that in a rectangular shape the entire cascade is arranged. (Kamimura, M.)

  9. Mathematical and physical modeling of rainfall in centrifuge

    OpenAIRE

    CAICEDO, Bernardo; THOREL, Luc; TRISTANCHO, Julian

    2015-01-01

    Rainfall simulation in centrifuge models is important for modelling soil-atmosphere interactions. However, the presence of Coriolis force, drag forces, evaporation and wind within the centrifuge may affect the distribution of rainfall over the model. As a result, development of appropriate centrifuge rain simulators requires a demanding process of experimental trial and error. This paper highlights the key factors involved in controlling rainfall in centrifuge simulations, develops a mathemat...

  10. Kinetically limited differential centrifugation as an inexpensive and readily available alternative to centrifugal elutriation.

    Science.gov (United States)

    Tan, Jinwang; Lee, Byung-Doo; Polo-Parada, Luis; Sengupta, Shramik

    2012-08-01

    When separating two species with similar densities but differing sedimentation velocities (because of differences in size), centrifugal elutriation is generally the method of choice. However, a major drawback to this approach is the requirement for specialized equipment. Here, we present a new method that achieves similar separations using standard benchtop centrifuges by loading the seperands as a layer on top of a dense buffer of a specified length, and running the benchtop centrifugation process for a calculated amount of time, thereby ensuring that all faster moving species are collected at the bottom, while all slower moving species remain in the buffer. We demonstrate the use of our procedure to isolate bacteria from blood culture broth (a mixture of bacterial growth media, blood, and bacteria).

  11. Centrifuge workers study. Phase II, completion report

    International Nuclear Information System (INIS)

    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

  12. 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.

  13. AIChe equipment testing procedure centrifugal compressors : a guide to performance evaluation and site testing

    CERN Document Server

    AIChE

    2013-01-01

    With its engineer-tested procedures and thorough explanations, Centrifugal Compressors is an essential text for anyone engaged in implementing new technology in equipment design, identifying process problems, and optimizing equipment performance.  This condensed book presents a step by step approach to preparing for, planning, executing, and analyzing tests of centrifugal compressors, with an emphasis on methods that can be conducted on-site and with an acknowledgement of the strengths and limitations of these methods. The book opens with an extensive and detailed section offering definitions

  14. The development of 128 ch fast multi channel pulse height analyzer for a tokamak plasmas

    International Nuclear Information System (INIS)

    Kawashima, Hisato; Matoba, Tohru; Ogawa, Toshihide; Kawakami, Tomohide

    1985-02-01

    A high counting rate multi channel pulse height analyzer was developed and tested to measure the detailed time evolution of X-ray energy spectrun radiated from a tokamak plasmas. Main developing objects of this analyzer are as follows. 1. The maximum counting rate and the minimum time resolution are 4 Mcps and 10 ms, respectively. 2. The energy resolution has ability to distinguish the characterisitic X-ray line. 3. Computer has to be used for operating system. This fast multi channel analyzer is using to measure the Soft X-ray spectrum on JFT-2M tokamak, and is confirmed to be useful for a practical measuring system. (author)

  15. Development of a 3D circular microfluidic centrifuge for the separation of mixed particles by using their different centrifuge times

    International Nuclear Information System (INIS)

    Jeon, H J; Kim, D I; Kim, M J; Nguyen, X D; Park, D H; Go, J S

    2015-01-01

    This paper presents a circular microfluidic centrifuge with two inlets and two outlets to separate mixed microparticles with a specially designed sample injection hole. To separate the mixed particles, it uses a rotational flow, generated in a chamber by counter primary flows in the microchannels. The shape and sizes of the circular microfluidic centrifuge have been designed through numerical evaluation to have a large relative centrifugal force. The difference of centrifuge times of the mixed particles of 1 μm and 6 μm was determined to be 8.2 s at an inlet Reynolds number of 500 and a sample Reynolds number of 20. In the experiment, this was measured to be about 10 s. From the separation of the two polymer particles analogous to the representative sizes of platelets and red blood cells, the circular microfluidic centrifuge shows a potential to separate human blood cells size-selectively by using the difference of centrifuge times. (paper)

  16. Waves in Strong Centrifugal Field

    Science.gov (United States)

    Bogovalov, S. V.; Kislov, V. A.; Tronin, I. V.

    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 polarization 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 modeling 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.

  17. Centrifugal force: a few surprises

    International Nuclear Information System (INIS)

    Abramowicz, M.A.; Max-Planck-Institut fuer Physik und Astrophysik, Garching

    1990-01-01

    The need for a rather fundamental revision in understanding of the nature of the centrifugal force is discussed. It is shown that in general relativity (and contrary to the situation in Newtonian theory) rotation of a reference frame is a necessary but not sufficient condition for the centrifugal force to appear. A sufficient condition for its appearance, in the instantaneously corotating reference frame of a particle, is that the particle motion in space (observed in the global rest frame) differs from a photon trajectory. The direction of the force is the same as that of the gradient of the effective potential for photon motion. In some cases, the centrifugal force will attract towards the axis of rotation. (author)

  18. Enlarging the operation range of a centrifugal compressor by cutting vanes based on CFD

    International Nuclear Information System (INIS)

    Mo, J T; Pan, X H; Gu, C H; Zheng, S Y

    2013-01-01

    Many centrifugal compressors are liable to insufficient operation range. The purpose of this paper is to enlarge the operation range of a centrifugal compressor used in turbocharger by cutting vanes. Some numerical works have been done based on CFD. The comparison of the calculated and measured results shows good agreement. The overall performance characteristics of the centrifugal compressor with different cutted vanes are observed and analyzed. The performance characteristic curves show that cutting vanes can increase the operation range by more than 50% with the loss of the highest efficiency limited in 1%. The flow fields are also shown in this paper and related explanations about the change of the performance characteristics curves are given. Shock wave is also detected in the simulation, and some related characteristics are summed up

  19. Plutonium purification cycle in centrifugal extractors: comparative study of flowsheets using uranous nitrate and hydroxylamine nitrate

    International Nuclear Information System (INIS)

    Baron, P.; Dinh, B.; Mauborgne, B.; Drain, F.; Gillet, B.

    1998-01-01

    The extension of the UP2 plant at La Hague includes a new plutonium purification cycle using multi-stage centrifugal extractors, to replace the present cycle which uses mixer/settler banks. The advantage of this type of extractor is basically the compactness of the equipment and the short residence time, which limits solvent degradation, particularly when reprocessing fuel containing a high proportion of plutonium 238. Two types of reducing agents have been considered for the plutonium stripping operation, uranous nitrate and hydroxylamine nitrate. Uranous nitrate displays a very fast reduction kinetics, ideal for the very short residence time of the phases in the centrifugal extractors. However, its extractability in the organic phase exacerbates the undesirable re-oxidation of plutonium, which is present in high concentration in this stage of the process. The short residence time of the centrifugal extractors is an advantage in as much as it could conceivably be adequate to obtain a sufficient reduction efficiency, while minimizing undesirable re-oxidation mechanisms. Hydroxylamine nitrate helps to minimize undesirable re-oxidation and is the normal choice for this type of operation. However, the plutonium (IV) reduction kinetics obtained is slower than with uranous nitrate, making it necessary to check whether its use is compatible with the very short residence times of centrifugal extractors.This article discusses the feasibility studies employing these two reducing agents. (author)

  20. NASA low speed centrifugal compressor

    Science.gov (United States)

    Hathaway, Michael D.

    1990-01-01

    The flow characteristics of a low speed centrifugal compressor were examined at NASA Lewis Research Center to improve understanding of the flow in centrifugal compressors, to provide models of various flow phenomena, and to acquire benchmark data for three dimensional viscous flow code validation. The paper describes the objectives, test facilities' instrumentation, and experiment preliminary comparisons.

  1. Separation of uranium isotopes by gas centrifugation

    International Nuclear Information System (INIS)

    Jordan, I.

    1980-05-01

    The uranium isotope enrichment is studied by means of the countercurrent gas centrifuge driven by thermal convection. A description is given of (a) the transfer and purification of the uranium hexafluoride used as process gas in the present investigation; (b) the countercurrent centrifuge ZG3; (c) the system designed for the introduction and extraction of the process gas from the centrifuge; (d) the measurement of the process gas flow rate through the centrifuge; (e) the determination of the uranium isotopic abundance by mass spectrometry; (f) the operation and mechanical behavior of the centrifuge and (g) the isotope separation experiments, performed, respectively, at total reflux and with production of enriched material. The results from the separation experiments at total reflux are discussed in terms of the enrichment factor variation with the magnitude and flow profile of the countercurrent given by the temperature difference between the rotor covers. As far as the separation experiments with production are concerned, the discussion of their results is presented through the variation of the enrichment factor as a function of the flow rate, the observed asymmetry of the process and the calculated separative power of the centrifuge. (Author) [pt

  2. Bacterial Cell Surface Damage Due to Centrifugal Compaction

    NARCIS (Netherlands)

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

    Centrifugal damage has been known to alter bacterial cell surface properties and interior structures, including DNA. Very few studies exist on bacterial damage caused by centrifugation because of the difficulty in relating centrifugation speed and container geometry to the damage caused. Here, we

  3. Centrifuge Facility for the International Space Station Alpha

    Science.gov (United States)

    Johnson, Catherine C.; Hargens, Alan R.

    1994-01-01

    The Centrifuge Facility planned for the International Space Station Alpha has under-one considerable redesign over the past year, primarily because the Station is now viewed as a 10 year mission rather than a 30 year mission and because of the need to simply the design to meet budget constraints and a 2000 launch date. The basic elements of the Centrifuge Facility remain the same, i.e., a 2.5 m diameter centrifuge, a micro-g holding unit, plant and animal habitats, a glovebox and a service unit. The centrifuge will still provide the full range of artificial gravity from 0.01 a to 2 - as originally planned; however, the extractor to permit withdrawal of habitats from the centrifuge without stopping the centrifuge has been eliminated. The specimen habitats have also been simplified and are derived from other NASA programs. The Plant Research Unit being developed by the Gravitational Biology Facility will be used to house plants in the Centrifuge Facility. Although not as ambitious as the Centrifuge Facility plant habitat, it will provide much better environmental control and lighting than the current Shuttle based Plant Growth Facility. Similarly, rodents will be housed in the Advanced Animal Habitat being developed for the Shuttle program. The Centrifuge Facility and ISSA will provide the opportunity to perform repeatable, high quality science. The long duration increments available on the Station will permit multigeneration studies on both plants and animals which have not previously been possible. The Centrifuge Facility will accommodate sufficient number of specimens to permit statistically significant sampling of specimens to investigate the time course of adaptation to altered gravity environments. The centrifuge will for the first time permit investigators to use gravity itself as a tool to investigate fundamental processes, to investigate the intensity and duration of gravity to maintain normal structure and function, to separate the effects of micro-g from

  4. Blade design loads on the flow exciting force in centrifugal pump

    International Nuclear Information System (INIS)

    Xu, Y; Yang, A L; Langand, D P; Dai, R

    2012-01-01

    The three-dimensional viscous flow field of two centrifugal pumps, which have the same volute, design head, design flow rate and rotational speed but the blade design load, are analyzed based on large eddy simulation. The comparisons are implemented including the hydraulic efficiencies, flow field characteristics, pressure pulsations and unsteady forces applied on the impellers to investigate the effect of the design blade load on hydraulic performance and flow exciting force. The numerical results show that the efficiency of the pump, the impeller blade of which has larger design load, is improved by 1.1%∼2.9% compared to the centrifugal pump with lower blade design load. The pressure fluctuation of the pump with high design load is more remarkable. Its maximum amplitude of coefficient of static pressure is higher by 43% than the latter. At the same time the amplitude of unsteady radial force is increased by 11.6% in the time domain. The results also imply that the blade design load is an important factor on the excitation force in centrifugal pumps.

  5. Description of a double centrifugation tube method for concentrating canine platelets.

    Science.gov (United States)

    Perazzi, Anna; Busetto, Roberto; Martinello, Tiziana; Drigo, Michele; Pasotto, Daniela; Cian, Francesco; Patruno, Marco; Iacopetti, Ilaria

    2013-07-22

    To evaluate the efficiency of platelet-rich plasma preparations by means of a double centrifugation tube method to obtain platelet-rich canine plasma at a concentration at least 4 times higher than the baseline value and a concentration of white blood cells not exceeding twice the reference range. A complete blood count was carried out for each sample and each concentrate. Whole blood samples were collected from 12 clinically healthy dogs (consenting blood donors). Blood was processed by a double centrifugation tube method to obtain platelet concentrates, which were then analyzed by a flow cytometry haematology system for haemogram. Platelet concentration and white blood cell count were determined in all samples. Platelet concentration at least 4 times higher than the baseline value and a white blood cell count not exceeding twice the reference range were obtained respectively in 10 cases out of 12 (83.3%) and 11 cases out of 12 (91.6%). This double centrifugation tube method is a relatively simple and inexpensive method for obtaining platelet-rich canine plasma, potentially available for therapeutic use to improve the healing process.

  6. Calculations of the Acceleration of Centrifugal Loading on Adherent Cells

    Science.gov (United States)

    Chen, Kang; Song, Yang; Liu, Qing; Zhang, Chunqiu

    2017-07-01

    Studies have shown that the morphology and function of living cells are greatly affected by the state of different high acceleration. Based on the centrifuge, we designed a centrifugal cell loading machine for the mechanical biology of cells under high acceleration loading. For the machine, the feasibility of the experiment was studied by means of constant acceleration or variable acceleration loading in the Petri dish fixture and/or culture flask. Here we analyzed the distribution of the acceleration of the cells with the change of position and size of the culturing device quantitatively. It is obtained that Petri dish fixture and/or culture flask can be used for constant acceleration loading by experiments; the centripetal acceleration of the adherent cells increases with the increase of the distance between the rotor center of the centrifuge and the fixture of the Petri dish and the size of the fixture. It achieves the idea that the general biology laboratory can conduct the study of mechanical biology at high acceleration. It also provides a basis for more accurate study of the law of high acceleration on mechanobiology of cells.

  7. Enhanced infectivity of bluetongue virus in cell culture by centrifugation.

    OpenAIRE

    Sundin, D R; Mecham, J O

    1989-01-01

    The effects of centrifugation of the infection of cell culture with bluetongue virus (BTV) were investigated. Baby hamster kidney cells were infected with BTV with or without centrifugation. Viral antigen was detected by immunofluorescence at 24 h in both centrifuged and noncentrifuged cultures. However, after 24 h of infection, the production of PFU in centrifuged cell cultures was 10- to 20-fold greater than that seen in cultures not centrifuged. In addition, centrifugation enhanced the dir...

  8. Plasma centrifugation does not influence thrombin-antithrombin and plasmin-antiplasmin levels but determines platelet microparticles count.

    Science.gov (United States)

    Stępień, Ewa; Gruszczyński, Krzysztof; Kapusta, Przemysław; Kowalik, Artur; Wybrańska, Iwona

    2015-01-01

    Centrifugation is an essential step for plasma preparation to remove residual elements in plasma, especially platelets and platelet-derived microparticles (PMPs). Our working hypothesis was that centrifugation as a preanalytical step may influence some coagulation parameters. Healthy young men were recruited (N=17). For centrifugation, two protocols were applied: (A) the first centrifugation at 2500xg for 15 min and (B) at 2500xg for 20 min at room temperature with a light brake. In protocol (A), the second centrifugation was carried out at 2500xg for 15 min, whereas in protocol (B), the second centrifugation involved a 10 min spin at 13,000 x g. Thrombin-antithrombin (TAT) and plasmin-antiplasmin (PAP) complexes concentrations were determined by enzyme-linked immunosorbent assays. PMPs were stained with CD41 antibody and annexin V, and analyzed by flow cytometry method. Procoagulant activity was assayed by the Calibrated Automated Thrombogram method as a slope of thrombin formation (CAT velocity). Median TAT and PAP concentrations did not differ between the centrifugation protocols. The high speed centrifugation reduced the median (IQR) PMP count in plasma from 1291 (841-1975) to 573 (391-1010) PMP/µL (P=0.001), and CAT velocity from 2.01 (1.31-2.88) to 0.97 (0.82-1.73) nM/min (P=0.049). Spearman's rank correlation analysis showed correlation between TAT and PMPs in the protocol A plasma which was (rho=0.52, PCentrifugation protocols do not influence the markers of plasminogen (PAP) and thrombin (TAT) generation but they do affect the PMP count and procoagulant activity.

  9. Performance prediction of industrial centrifuges using scale-down models.

    Science.gov (United States)

    Boychyn, M; Yim, S S S; Bulmer, M; More, J; Bracewell, D G; Hoare, M

    2004-12-01

    Computational fluid dynamics was used to model the high flow forces found in the feed zone of a multichamber-bowl centrifuge and reproduce these in a small, high-speed rotating disc device. Linking the device to scale-down centrifugation, permitted good estimation of the performance of various continuous-flow centrifuges (disc stack, multichamber bowl, CARR Powerfuge) for shear-sensitive protein precipitates. Critically, the ultra scale-down centrifugation process proved to be a much more accurate predictor of production multichamber-bowl performance than was the pilot centrifuge.

  10. Headlines... Areva on the way toward centrifugation

    International Nuclear Information System (INIS)

    Anon.

    2004-01-01

    The French industrial group Areva, that gathers Cogema and Framatome-ANP, has entered into a partnership with the British nuclear consortium Urenco for creating ETC (enrichment technology company) in order to replace its uranium enrichment facility (Georges-Besse-I) that is planned to close in 2012 by a new one (George-Besse-II) that will enter into service as early as 2007. The new facility will be based on the centrifugation technique developed by Urenco, this technique will cut the consumption of electricity by 3 in comparison with the gaseous diffusion technique used in the Georges-Besse-I facility. The other asset of the centrifugation technique is that the facility can grow with the number of centrifuges that are set. In 2007 only 7% of the total number of centrifuges will be installed, which will sufficient to satisfy the demand for enriched uranium. The full size of the facility will be reached in 2016 through gradual steps of 10% more centrifuges set every year. (A.C.)

  11. Instabilities expected to exist in a gas centrifuge

    International Nuclear Information System (INIS)

    Sakurai, Takeo

    1977-01-01

    A typical counter current type centrifuge of long bowl geometry is schematically shown. At first glance, the main flow field in this centrifuge can be taken as a swirling pipe flow. Taking in mind the operating gas (uranium hexafluoride) the temperature of which is 20 deg C and the peripheral pressure 10 torrs, the density and pressure obey the barometric relation in which the gravity is replaced by the centrifugal acceleration; in a thermally driven centrifuge, an additional weak temperature gradient appears along the axial direction. These situations are similar to those in the earth's atmosphere. So, it is stressed that the interior of a gas centrifuge is a new kind of rotating atmosphere and offers a 'new face' in the field of geophysical fluid dynamics. Instabilities in inviscid case and the destabilizing effects of the diffusivity are thus discussed together with the effects of the mechanical vibrations of the centrifuge, and vortex breakdown phenomena

  12. DESIGN PARAMETERS OF CENTRIFUGAL COMPRESSOR INDUCER

    Directory of Open Access Journals (Sweden)

    Saim KOÇAK

    1998-03-01

    Full Text Available Design characteristics of centrifugal compressor impellers working with compressible fluids are analyzed, and the design parameters of inducer are defined. The effects of incidence, deviation and deflection angles, relative eddy, rotating stall and Mach number are investigated. The relation between minimum relative Mach number of inducer and flow angle is investigated and it is observed that the minimum Mach number occurs for flow angle values between -680 and -520 . In the design, the effect of a 100 difference in flow angle is found to be less than 1 % on minimum relative Mach number.

  13. Simulation of ultra-long term behavior in HLW near-field by centrifugal model test. Part 1. Development of centrifugal equipment and centrifuge model test method

    International Nuclear Information System (INIS)

    Nishimoto, Soshi; Okada, Tetsuji; Sawada, Masataka

    2011-01-01

    The objective of this paper is to develop a centrifugal equipment which can continuously be run for a long time and a model test method in order to evaluate a long term behavior which is a coupled thermo-hydro-mechanical processes in the high level wastes geological disposal repository and the neighborhood (called 'near-field'). The centrifugal equipment of CRIEPI, 'CENTURY5000-THM', developed in the present study is able to run continuously up to six months. Therefore, a long term behavior in the near-field can be simulated in a short term, for instance, the behavior for 5000 equivalent years can be simulated in six months by centrifugalizing 100 G using a 1/100 size model. We carried out a test using a nylon specimen in a centrifugal force field of 30 G and confirmed the operations of CENTURY5000-THM, control and measurement for 11 days. As the results, it was able to control the stress in the pressure vessel and measure the values of strain, temperature and pressure. And, as a result of scanning the small model of near-field including the metal overpack, bentonite buffer and rock by a medical X-rays CT scanner, the internal structure of the model was able to be evaluated when the metal artifact was reduced. From these results, the evaluation for a long term behavior of a disposal repository by the method of centrifugal model test became possible. (author)

  14. The gas centrifuge, uranium enrichment and nuclear proliferation

    International Nuclear Information System (INIS)

    Chapman, A.

    1988-01-01

    The author considers the consequences for controlling nuclear proliferation of the emergence of the gas centrifuge method for enriching uranium and succeeds in the difficult and delicate task of saying enough about gas centrifuge techniques for readers to judge, what may be involved in fully embracing gas centrifuge enrichment within the constraints of an anti-proliferation strategy, whilst at the same time saying nothing that could be construed as encouraging an interest in the gas centrifuge route to highly enriched uranium where none had before existed. (author)

  15. Effects of centrifugal modification of magnetohydrodynamic equilibrium on resistive wall mode stability

    International Nuclear Information System (INIS)

    Shiraishi, J.; Aiba, N.; Miyato, N.; Yagi, M.

    2014-01-01

    Toroidal rotation effects are self-consistently taken into account not only in the linear magnetohydrodynamic (MHD) stability analysis but also in the equilibrium calculation. The MHD equilibrium computation is affected by centrifugal force due to the toroidal rotation. To study the toroidal rotation effects on resistive wall modes (RWMs), a new code has been developed. The RWMaC modules, which solve the electromagnetic dynamics in vacuum and the resistive wall, have been implemented in the MINERVA code, which solves the Frieman–Rotenberg equation that describes the linear ideal MHD dynamics in a rotating plasma. It is shown that modification of MHD equilibrium by the centrifugal force significantly reduces growth rates of RWMs with fast rotation in the order of M 2  = 0.1 where M is the Mach number. Moreover, it can open a stable window which does not exist under the assumption that the rotation affects only the linear dynamics. The rotation modifies the equilibrium pressure gradient and current density profiles, which results in the change of potential energy including rotational effects. (paper)

  16. 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.

  17. Autobalancing and FDIR for a space-based centrifuge prototype

    Science.gov (United States)

    Wilson, Edward; Mah, Robert W.

    2005-01-01

    This report summarizes centrifuge-related work performed at the Smart Systems Research Laboratory at NASA Ames Research Center's Computational Sciences Division from 1995 through 2003. The goal is to develop an automated system that will sense an imbalance (both static and dynamic3) in a centrifuge and issue control commands to drive counterweights to eliminate the effects of the imbalance. This autobalancing development began when the ISS centrifuge design was not yet finalized, and was designed to work with the SSRL Centrifuge laboratory prototype, constructed in 1993-1995. Significant differences between that prototype and the current International Space Station (ISS) Centrifuge design are that: the spin axis for the SSRL Centrifuge prototype can translate freely in x and y, but not wobble, whereas the ISS centrifuge spin axis has 3 translational and two rotational degrees of freedom, supported by a vibration 34. The imbalance sensors are strained gauges both in the rotor and the stator, measuring the imbalance forces, whereas the ISS centrifuge uses eddy current displacement sensors to measure the displacements resulting from imbalance. High fidelity autobalancing and FDIR systems (for both counterweights and strain gauges) are developed and tested in MATLAB simulation, for the SSRL Centrifuge configuration. Hardware implementation of the autobalancing technology was begun in 1996, but was terminated due to lack of funding. The project lay dormant until 2001-2002 when the FDIR capability was added.

  18. High frequency dynamics in centrifugal compressors

    NARCIS (Netherlands)

    Twerda, A.; Meulendijks, D.; Smeulers, J.P.M.; Handel, R. van den; Lier, L.J. van

    2008-01-01

    Problems with centrifugal compressors relating to high frequency, i.e. Blade passing frequency (BPF) are increasing. Pulsations and vibrations generated in centrifugal compressors can lead to nuisance, due to strong tonal noise, and even breakdown. In several cases the root cause of a failure or a

  19. Thermal analysis of a gas centrifuge

    International Nuclear Information System (INIS)

    Andrade, D.A.; Bastos, J.L.F.; Maiorino, J.R.

    1996-01-01

    The centrifuge separation efficiency is the result of the composition of the centrifuge field to the secondary flow in the axial direction near to the rotor wall. For a given machine, the centrifuge field can not be altered and the effort to augment the separation efficiency should be concentrated on the secondary flow. The secondary flow has a mechanical and a thermal component. The mechanical component is due to the deceleration of the gas at the scoop region. The thermal component is due to the temperature differences at the rotor. This paper presents a thermal model of a centrifuge in order to understand the main heat transfer mechanisms and to establish the boundary conditions for a fluid flow computer code. The heat transfer analysis takes into account conduction at the structure parts of the rotor and shell, radiation with multi-reflections between the rotor and the shell, and convection to the ambient. (author)

  20. Safety aspects of gas centrifuge enrichment plants

    International Nuclear Information System (INIS)

    Hansen, A.H.

    1987-01-01

    Uranium enrichment by gas centrifuge is a commercially proven, viable technology. Gas centrifuge enrichment plant operations pose hazards that are also found in other industries as well as unique hazards as a result of processing and handling uranium hexafluoride and the handling of enriched uranium. Hazards also found in other industries included those posed by the use of high-speed rotating equipment and equipment handling by use of heavy-duty cranes. Hazards from high-speed rotating equipment are associated with the operation of the gas centrifuges themselves and with the operation of the uranium hexafluoride compressors in the tail withdrawal system. These and related hazards are discussed. It is included that commercial gas centrifuge enrichment plants have been designed to operate safely

  1. Centrifugal Casting Features/Metallurgical Characterization of Aluminum Alloys

    International Nuclear Information System (INIS)

    Chirita, G.; Soares, D.; Cruz, D.; Silva, F. S.; Stefanescu, I.

    2008-01-01

    This paper deals with the study of centrifugal effects on aluminium castings under high G values. Most of the studies in this domain (FGMs obtained by centrifugal casting) deal with functionally graded composites reinforced with a solid phase such as silicon particles or others. However, in this study it will be shown that unreinforced aluminium alloys may be significantly influenced by the centrifugal effect and that functionally graded castings are also obtained. It has been observed that the centrifugal effect may increase in some alloys, depending on the relative position in the castings, the rupture strength by approx. 50%, and rupture strain by about 300%, as compared to the gravity casting technique. The Young's modulus may also increase by about 20%. It has also been reported that in vertical centrifugal castings there are mainly three aspects that affect the components thus obtained, namely: fluid dynamics; vibration (inherent to the system); and centrifugal force. These features have a different effect on the castings depending on the aluminium alloy. In this paper, an analysis of the most important effects of the centrifugal casting process on metallurgical features is conducted. A solidification characterization at several points along the mould will be made in order to have an accurate idea of both the fluid dynamics inside the mould during the casting and the solidification behavior in different parts of the component. These two analyses will be related to the metallurgical properties (phase distribution; SDAS; eutectic silicon content and shape, pores density and shape) along the component and mainly along the direction of the centrifugal pressure. A comparison between castings obtained by both centrifugal casting technique and gravity casting technique is made for reference (gravity casting)

  2. Improved g-level calculations for coil planet centrifuges.

    Science.gov (United States)

    van den Heuvel, Remco N A M; König, Carola S

    2011-09-09

    Calculation of the g-level is often used to compare CCC centrifuges, either against each other or to allow for comparison with other centrifugal techniques. This study shows the limitations of calculating the g-level in the traditional way. Traditional g-level calculations produce a constant value which does not accurately reflect the dynamics of the coil planet centrifuge. This work has led to a new equation which can be used to determine the improved non-dimensional values. The new equations describe the fluctuating radial and tangential g-level associated with CCC centrifuges and the mean radial g-level value. The latter has been found to be significantly different than that determined by the traditional equation. This new equation will give a better understanding of forces experienced by sample components and allows for more accurate comparison between centrifuges. Although the new equation is far better than the traditional equation for comparing different types of centrifuges, other factors such as the mixing regime may need to be considered to improve the comparison further. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Development of centrifuge modeling for evaluating the mechanisms of collapse above underground openings

    International Nuclear Information System (INIS)

    Davis, B.C.; Kutter, B.L.; Chang, J.D.L.

    1988-01-01

    Improved prediction of surface collapse above an underground cavity is important in many LLNL programs, including Nuclear Test. To improve the predictive capability, LLNL must better understand the mechanisms involved in the process of collapse. The research aims to develop the centrifuge technique for modeling mechanisms of underground collapse in soil. The authors will also evaluate the adequacy of existing constitutive or flow models of soils for modeling underground collapse. During FY 86, using the centrifuge at University of California, Davis, the authors developed the basic centrifugal modeling technique, conducted experiments, and modeled the process on a computer. In FY 87, they continued to develop the experimental method and analyze results. Results to date have shown that the model dimensions are not necessarily the critical dimensions (i.e., those determining the adequacy of the model). Rather, the critical dimension is the diameter of the chimney above the opening that develops during collapse

  4. Achieving an ever-improving centrifuge

    International Nuclear Information System (INIS)

    Edwards, T.T.; Wilcox, P.

    1988-01-01

    To ensure that the latest technical innovations can be rapidly incorporated, centrifuge development in the Urenco organization is carried out in different phases simultaneously on different generations of machines. This system has led to progressively increased outputs and reduced specific costs, and with the further known potential available, is expected to maintain Urenco's competitiveness throughout the 1990s. The process of separating isotopes by centrifuge is described. (author)

  5. Rhie-Chow interpolation in strong centrifugal fields

    Science.gov (United States)

    Bogovalov, S. V.; Tronin, I. V.

    2015-10-01

    Rhie-Chow interpolation formulas are derived from the Navier-Stokes and continuity equations. These formulas are generalized to gas dynamics in strong centrifugal fields (as high as 106 g) occurring in gas centrifuges.

  6. 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...

  7. Modeling centrifugal cell washers using computational fluid dynamics.

    Science.gov (United States)

    Kellet, Beth E; Han, Binbing; Dandy, David S; Wickramasinghe, S Ranil

    2004-11-01

    Reinfusion of shed blood during surgery could avoid the need for blood transfusions. Prior to reinfusion of the red blood cells, the shed blood must be washed in order to remove leukocytes, platelets, and other contaminants. Further, the hematocrit of the washed blood must be increased. The feasibility of using computational fluid dynamics (CFD) to guide the design of better centrifuges for processing shed blood is explored here. The velocity field within a centrifuge bowl and the rate of protein removal from the shed blood has been studied. The results obtained indicate that CFD could help screen preliminary centrifuge bowl designs, thus reducing the number of initial experimental tests required when developing new centrifuge bowls. Although the focus of this work is on washing shed blood, the methods developed here are applicable to the design of centrifuge bowls for other blood-processing applications.

  8. Decontamination of nuclear fuels with centrifugal separation

    International Nuclear Information System (INIS)

    Ning, Li; Camassa, R.; Ecke, R.; Venneri, F.

    1995-01-01

    The treatment and disposal of nuclear material is a crucial element in today's nuclear power industry. We present a physical process of centrifugal separation that has potential to deal with existing waste and provide opportunities for realizing advanced accelerator-driven power generation. In our proposed process a liquid metal solution containing actinides and fission products is fed through a series of continuous flow centrifuges. We show fundamentals of centrifugation including theory and experiments and estimate how the processing can be optimized

  9. Decontamination of nuclear fuels with centrifugal separation

    International Nuclear Information System (INIS)

    Ning, L.; Camassa, R.; Ecke, R.; Venneri, F.

    1995-01-01

    The treatment and disposal of nuclear material is a crucial element in today's nuclear power industry. We present a physical process of centrifugal separation that has potential to deal with existing waste and provide opportunities for realizing advanced accelerator driven power generation. In our proposed process a liquid metal solution containing actinides and fission products is fed through a series of continuous flow centrifuges. We show fundamentals of centrifugation including theory and experiments and estimate how the processing can be optimized. (authors)

  10. Experimental study of multi-component separation by gas centrifuge

    International Nuclear Information System (INIS)

    Zhou, M.S.; Liang, X.W.; Chen, W.N.; Yin, Y.T.

    2006-01-01

    Stable isotopes are applied in many areas and most stable isotopes are multi-component, This paper presents experimental results of several stable isotopes separation conducted in Tsinghua University by using ultra-speed gas centrifuges. Xe, WF 6 , TeF 6 , SiHCl 3 , SiF 4 were chosen as the process gases. By adjusting some of the centrifuge's parameters, the suitable centrifuge parameters for different process gas separations were found and the overall unit separation factors γ 0 were obtained by means of single gas centrifuge separation. The experimental results show that with appropriate process gases, stable isotope separation by gas centrifuge was effective. (authors)

  11. Numerical simulation of flow in centrifugal pump under cavitation and sediment condition

    International Nuclear Information System (INIS)

    Lu, J L; Guo, P C; Zheng, X B; Zhao, Q; Luo, X Q

    2012-01-01

    The sediment concentration is very high in many rivers in the world, especially in China. The pumps that designed for the clear water are usually seriously abraded. The probability of pump cavitation is greatly enhanced due to the existence of sand. Under the joint action and mutual promotion of sand erosion and cavitation, serious abrasion could occurred, and the hydraulic performance of the pump may be greatly descended, meanwhile the safety and stability of the whole pump are greatly threatened. Therefore, it is significant to investigate the cavitation characteristic of pump under sediment flow condition. In this paper, the flow in a single stage centrifugal pump under cleat water and sediment flow conditions was numerically simulated. The cavitation performance under clear water was firstly analyzed. Then, The pressure, velocity and solid particle distribution in centrifugal pump under different particle diameter and different particle concentration was investigated by using the two-fluid model; The area and extent of erosion was illustrated by using the particle track model. Finally, the influence of mixed sand on centrifugal pump performance was investigated.

  12. Evaluation of single and double centrifugation tube methods for concentrating equine platelets.

    Science.gov (United States)

    Argüelles, D; Carmona, J U; Pastor, J; Iborra, A; Viñals, L; Martínez, P; Bach, E; Prades, M

    2006-10-01

    The aim of this study was to evaluate single and double centrifugation tube methods for concentrating equine platelets. Whole blood samples were collected from clinically normal horses and processed by use of single and double centrifugation tube methods to obtain four platelet concentrates (PCs): PC-A, PC-B, PC-C, and PC-D, which were analyzed using a flow cytometry hematology system for hemogram and additional platelet parameters (mean platelet volume, platelet distribution width, mean platelet component concentration, mean platelet component distribution width). Concentrations of transforming growth factor beta 1 (TGF-beta(1)) were determined in all the samples. Platelet concentrations for PC-A, PC-B, PC-C, and PC-D were 45%, 44%, 71%, and 21% higher, respectively, compared to the same values for citrated whole blood samples. TGF-beta(1) concentrations for PC-A, PC-B, PC-C, and PC-D were 38%, 44%, 44%, and 37% higher, respectively, compared to citrated whole blood sample values. In conclusion, the single and double centrifugation tube methods are reliable methods for concentrating equine platelets and for obtaining potentially therapeutic TGF-beta(1) levels.

  13. Optimization of centrifugal pump cavitation performance based on CFD

    International Nuclear Information System (INIS)

    Xie, S F; Wang, Y; Liu, Z C; Zhu, Z T; Ning, C; Zhao, L F

    2015-01-01

    In order to further improve the cavitation performance of a centrifugal pump, slots on impeller blade near inlet were studied and six groups of hydraulic model were designed. Base on cavitating flow feature inside a centrifugal pump, bubble growth and implosion are calculated from the Rayleigh-Plesset equation which describes the dynamic behavior of spherical bubble and RNG κ-ε model was employed to simulate and analyze the internal two-phase flow of the model pump under the same conditions. The simulation results show that slots on blade near inlet could improve the cavitation performance and cavitation performance improvement of the second group was more obvious. Under the same conditions, the pressure on the back of blade near inlet was higher than the pressure on the back of unmodified blade near inlet, and energy distribution in the flow channel between the two blades was more uniform with a small change of head

  14. Design and test of a high pressure centrifugal compressor

    International Nuclear Information System (INIS)

    Choi, Jae Ho; Han, Chak Heui; Paeng, Ki Seok; Chen, Seung Bae; Kim, Yong Ryun

    2005-01-01

    This paper presents an aerodynamic design, flow analysis and performance test of a pressure ratio 4:1 centrifugal compressor for gas turbine engine. The compressor is made up of a centrifugal impeller, a two-stage diffuser consisted of radial and axial types. The impeller has a 45 degree backswept angle and the design running tip clearance is 5% of impeller exit height. Three-dimensional numerical analysis is performed to analyze the flows in the impeller, diffuser and deswirler considering the impeller tip clearance. Test module and rig facilities for the compressor stage performance test are designed and fabricated. The overall compressor stage performances as well as the static pressure fields on the impeller and diffuser are measured. Two diffusers of wedge and airfoil types are tested with an impeller. The calculation and test results show that flow fields downstream the deswirler at the design and off-design points are highly nonuniform and the airfoil diffuser has the better aerodynamic characteristics than those of wedge diffuser

  15. Effect of Centrifuge Temperature on Routine Coagulation Tests.

    Science.gov (United States)

    Yazar, Hayrullah; Özdemir, Fatma; Köse, Elif

    2018-01-01

    This study investigated the effects of cooled and standard centrifuges on the results of coagulation tests to examine the effects of centrifugation temperature. Equal-volume blood samples from each patient were collected at the same time intervals and subjected to standard (25°C) and cooled centrifugation (2-4°C). Subsequently, the prothrombin time (PT), international normalized ratio (INR), activated partial thromboplastin time (aPTT), fibrinogen, and D-dimer values were determined in runs with the same lot numbers in the same coagulation device using the Dia-PT R (PT and INR), Dia-PTT-liquid (aPTT), Dia-FIB (fibrinogen), and Dia-D-dimer kits, respectively. The study enrolled 771 participants. The PT was significantly (p centrifuges were as follows: PT 10.30 versus 10.50 s; PT (INR) 1.04 versus 1.09 s; APTT 28.90 versus 29.40 s; fibrinogen 321.5 versus 322.1 mg/dL; and D-dimer 179.5 versus 168.7 µg FEU/mL. There were significant differences (p centrifuges. Centrifuge temperature can have a significant effect on the results of coagulation tests. However, broad and specific disease-based studies are needed. © 2018 S. Karger AG, Basel.

  16. Development of uranium enrichment technology by gas centrifugation

    International Nuclear Information System (INIS)

    Sibata, Tomofumi; Kai, Tsunetoshi

    1996-01-01

    The development of a gas-centrifuge for uranium enrichment has been conducted by Power Reactor and Nuclear Fuel Development Corporation in Japan after the first several years' fruitless works, the R and D works came to the point and continuing rapid improvements of centrifuges have started, Cascade tests were given with C-1 and C-2 cascade experimental facilities. Life, reliability and feasibility tests were given with the pilot plant and the demonstration plant. As a result of these works, the private commercial plant has started the operation. Although the main efforts were devoted to the development of metal rotor centrifuges in the course mentioned above, composite material rotor centrifuges have also been developed in parallel to achieve higher performance. Promising results have been being obtained with cascade test facilities on the pilot plant scale. Furthermore, R and D works are being proceeded on more excellent and advanced centrifuges. (author)

  17. Isotopic enrichment in a plasma centrifuge

    International Nuclear Information System (INIS)

    Del Bosco, E.; Dallaqua, R.S.; Ludwig, G.O.; Bittencourt, J.A.

    1987-01-01

    High rotational velocity and centrifugal isotopic separation of carbon in a vacuum-arc plasma centrifuge are presented. Enrichments of up to 390% for 13 C are measured at 6 cm radius with angular rotation frequencies in excess of 1.0 x 10 5 rad/s in an axial magnetic field of 0.12 T

  18. Engineering design of centrifugal casting machine

    Science.gov (United States)

    Kusnowo, Roni; Gunara, Sophiadi

    2017-06-01

    Centrifugal casting is a metal casting process in which metal liquid is poured into a rotating mold at a specific temperature. Given round will generate a centrifugal force that will affect the outcome of the casting. Casting method is suitable in the manufacture of the casting cylinder to obtain better results. This research was performed to design a prototype machine by using the concept of centrifugal casting. The design method was a step-by-step systematic approach in the process of thinking to achieve the desired goal of realizing the idea and build bridges between idea and the product. Design process was commenced by the conceptual design phase and followed by the embodiment design stage and detailed design stage. With an engineering design process based on the method developed by G. E. Dieter, draft prototype of centrifugal casting machine with dimension of 550×450×400 mm, ¼ HP motor power, pulley and belt mechanism, diameter of 120-150mm, simultaneously with the characteristics of simple casting product, easy manufacture and maintenance, and relatively inexpensive, was generated.

  19. 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.

  20. 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)

  1. 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...... for the centrifugal microfluidics platform and cover optical as well as mechanical and electrical detection principles....

  2. Plasma instability of a vacuum arc centrifuge

    International Nuclear Information System (INIS)

    Hole, M.J.; Dallaqua, R.S.; Simpson, S.W.; Del Bosco, E.

    2002-01-01

    Ever since conception of the vacuum arc centrifuge in 1980, periodic fluctuations in the ion saturation current and floating potential have been observed in Langmuir probe measurements in the rotation region of a vacuum arc centrifuge. In this work we develop a linearized theoretical model to describe a range of instabilities in the vacuum arc centrifuge plasma column, and then test the validity of the description through comparison with experiment. We conclude that the observed instability is a 'universal' instability, driven by the density gradient, in a plasma with finite conductivity

  3. Modern gas centrifuge and rarefied-gas dynamics

    International Nuclear Information System (INIS)

    Lowry, R.A.; Halle, E.V.; Wood, H.G. III.

    1981-01-01

    Today, the modern gas centrifuge appears to be the preferred method for the enrichment of the isotopes of uranium on a commercial scale. That this is the case is the result of diligent development programs pursued in this country as well as in the UK, Germany, and the Netherlands over the several decades since the end of WW II. The theoretical modelling of gas centrifuge performance has made notable advances. However, the theoretical work has been based primarily on continuum fluid dynamics considerations. Centrifuge problems involving rarefied gas dynamics considerations are discussed in this paper

  4. Subjective stress factors in centrifuge training for military aircrews.

    Science.gov (United States)

    Lin, Pei-Chun; Wang, Jenhung; Li, Shih-Chin

    2012-07-01

    This study investigates stress-influence factors perceived by military aircrews undergoing centrifuge training, which lowers the incidence of G-induced loss of consciousness (G-LOC) for the crews of high-performance combat aircrafts. We used questionnaires to assess the subjective stress-influence factors of crews undergoing centrifuge training. Professionals in aviation physiology identified attributes measuring the perceived stress induced by centrifuge training, which were segmented into three constructs by factor analysis, theory lecture, centrifuge equipment, and physical fitness. Considerable interpenetration was discernible between these factors and military rank, age, length of service, flight hours accrued, and type of aircraft piloted. Identifying and quantifying the perceived stressors experienced in human-use centrifuge training enables aviators, astronauts, and air forces of the world to determine which constructs perceptibly increase or alleviate the perceived stress undergone by trainees when partaking in centrifuge training. Copyright © 2011 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  5. Bifurcated equilibria in centrifugally confined plasma

    International Nuclear Information System (INIS)

    Shamim, I.; Teodorescu, C.; Guzdar, P. N.; Hassam, A. B.; Clary, R.; Ellis, R.; Lunsford, R.

    2008-01-01

    A bifurcation theory and associated computational model are developed to account for abrupt transitions observed recently on the Maryland Centrifugal eXperiment (MCX) [R. F. Ellis et al. Phys. Plasmas 8, 2057 (2001)], a supersonically rotating magnetized plasma that relies on centrifugal forces to prevent thermal expansion of plasma along the magnetic field. The observed transitions are from a well-confined, high-rotation state (HR-mode) to a lower-rotation, lesser-confined state (O-mode). A two-dimensional time-dependent magnetohydrodynamics code is used to simulate the dynamical equilibrium states of the MCX configuration. In addition to the expected viscous drag on the core plasma rotation, a momentum loss term is added that models the friction of plasma on the enhanced level of neutrals expected in the vicinity of the insulators at the throats of the magnetic mirror geometry. At small values of the external rotation drive, the plasma is not well-centrifugally confined and hence experiences the drag from near the insulators. Beyond a critical value of the external drive, the system makes an abrupt transition to a well-centrifugally confined state in which the plasma has pulled away from the end insulator plates; more effective centrifugal confinement lowers the plasma mass near the insulators allowing runaway increases in the rotation speed. The well-confined steady state is reached when the external drive is balanced by only the viscosity of the core plasma. A clear hysteresis phenomenon is shown.

  6. 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.

  7. Surface-Enhanced Raman Spectroscopy Integrated Centrifugal Microfluidics Platform

    DEFF Research Database (Denmark)

    Durucan, Onur

    This PhD thesis demonstrates (i) centrifugal microfluidics disc platform integrated with Au capped nanopillar (NP) substrates for surface-enhanced Raman spectroscopy (SERS) based sensing, and (ii) novel sample analysis concepts achieved by synergistical combination of sensing techniques and minia......This PhD thesis demonstrates (i) centrifugal microfluidics disc platform integrated with Au capped nanopillar (NP) substrates for surface-enhanced Raman spectroscopy (SERS) based sensing, and (ii) novel sample analysis concepts achieved by synergistical combination of sensing techniques...... dense array of NP structures. Furthermore, the wicking assisted nanofiltration procedure was accomplished in centrifugal microfluidics platform and as a result additional sample purification was achieved through the centrifugation process. In this way, the Au coated NP substrate was utilized...

  8. Impact of dehydration and fasting on intraocular pressure and corneal biomechanics measured by the Ocular Response Analyzer.

    Science.gov (United States)

    Uysal, Betul Seher; Duru, Necati; Ozen, Umut; Arikan Yorgun, Mucella; Akcay, Emine; Caglayan, Mehtap; Cagil, Nurullah

    2018-04-01

    To investigate the effects of dehydration and fasting on the intraocular pressure (IOP) and corneal biomechanics during Ramadan in healthy subjects. A total of 36 healthy fasting male volunteers with a mean age of 32.7 ± 5.1 years (range 28-38 years) were enrolled in the study. A Reichert Ocular Response Analyzer (ORA) was used to measure the corneal resistance factor (CRF), corneal hysteresis (CH), Goldman-correlated IOP (IOPg), and corneal-compensated IOP (IOPcc), additionally IOP with Goldmann applanation tonometer (IOP-GAT) was taken. All measurements were recorded at 8:00 am and 4:00 p.m. during Ramadan and during a 1-month follow-up after Ramadan was over. Statistical analysis demonstrated no difference in the ORA measurements including CH, CRF, IOPcc, and IOPg; CCT and CV values between fasting and non-fasting periods or within a single day (diurnal changes). Nine volunteers (25% of total subjects) were excluded because eyedrops were believed to disrupt the Ramadan fast consequently IOP-GAT could not be measured from these subjects. No statistically significant difference was noted between IOP-GAT and IOPg measurements of twenty-seven subjects at the different periods and time points. Our results reveal that fasting during Ramadan does not profoundly affect corneal biomechanics and IOP values in healthy volunteers without ocular diseases such as glaucoma. When planning corneal refractive surgery and determining IOP, the ORA measurements can be done safely during a Ramadan fast. Moreover, ORA may be a better alternative for patients that refuse IOP measurement via GAT for examining the accuracy of IOP during fasting. Further studies are needed to better understand the role of these parameters on corneal disease and glaucoma during fasting.

  9. Centrifugal potential energy : an astounding renewable energy concept

    Energy Technology Data Exchange (ETDEWEB)

    Oduniyi, I.A. [Aled Conglomerate Nigeria Ltd., Lagos (Nigeria)

    2010-07-01

    A new energy concept known as centrifugal potential energy was discussed. This new energy concept is capable of increasing the pressure, temperature and enthalpy of a fluid, without having to apply work or heat transfer to the fluid. It occurs through a change in the centrifugal potential energy of the flowing fluid in a rotating frame of reference or a centrifugal force field, where work is performed internally by the centrifugal weight of the fluid. This energy concept has resulted in new energy equations, such as the Rotational Frame Bernoulli's Equation for liquids and the Rotational Frame Steady-Flow Energy Equation for gases. Applications of these equations have been incorporated into the design of centrifugal field pumps and compressors. Rather than compressing a fluid with a physical load transfer, these devices can compress a fluid via the effect of centrifugal force applied to the object. A large amount of energy is therefore produced when this high pressure compressed working fluid expands in a turbine. When water is used as the working fluid, it could reach renewable energy densities in the range of 25-100 kJ/kg of water. When atmospheric air is used, it could reach energy densities in the range of 500-1,500 kJ/kg of air.

  10. 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....

  11. Enrichment technology. Dependable vendor of gas centrifuges

    International Nuclear Information System (INIS)

    Anon.

    2011-01-01

    Enrichment Technology is an innovative, high-tech company that develops, manufactures and installs gas centrifuges for enriching uranium. In addition, Enrichment Technology designs enrichment plants that use gas centrifuge technology. This technology offers the most efficient and cost-effective method for enriching uranium yet: high-performance, safe technology that dominates the market with a global share of 45 percent. A determining factor in Enrichment Technology's success is its mission: supplying its customers with safe, reliable technology. Production of the centrifuges requires versatile know-how and collaboration between different departments as well as interdisciplinary teams at the various sites. More than 2000 operators at 8 sites in 5 countries contribute their individual knowledge and personal skills in order to produce this exceptional technology. The head office is in Beaconsfield near London and the operational headquarters are in Almelo in the Netherlands. There are other sites in Germany (Juelich und Gronau), Great Britain (Capenhurst) as well as project sites in the USA and France. Capenhurst is where experienced engineers design new enrichment plants and organise their construction. Centrifuge components are manufactured in Almelo and Juelich, while the pipework needed to connect up the centrifuges is produced at the site in Gronau. In Juelich, highly qualified scientists in interdisciplinary teams are continuously researching ways of improving the current centrifuges. Communication between specialists in the fields of chemistry, physics and engineering forms the basis for the company's success and the key to extending this leading position in the global enrichment market. (orig.)

  12. Hemocompatibility of Axial Versus Centrifugal Pump Technology in Mechanical Circulatory Support Devices.

    Science.gov (United States)

    Schibilsky, David; Lenglinger, Matthias; Avci-Adali, Meltem; Haller, Christoph; Walker, Tobias; Wendel, Hans Peter; Schlensak, Christian

    2015-08-01

    The hemocompatible properties of rotary blood pumps commonly used in mechanical circulatory support (MCS) are widely unknown regarding specific biocompatibility profiles of different pump technologies. Therefore, we analyzed the hemocompatibility indicating markers of an axial flow and a magnetically levitated centrifugal device within an in vitro mock loop. The HeartMate II (HM II; n = 3) device and a CentriMag (CM; n = 3) adult pump were investigated in a human whole blood mock loop for 360 min using the MCS devices as a driving component. Blood samples were analyzed by enzyme-linked immunosorbent assay for markers of coagulation, complement system, and inflammatory response. There was a time-dependent activation of the coagulation (thrombin-antithrombin complexes [TAT]), complement (SC5b-9), and inflammation system (polymorphonuclear [PMN] elastase) in both groups. The mean value of TAT (CM: 4.0 μg/L vs. 29.4 μg/L, P technologies and a magnetically levitated centrifugal pump design might be superior. Copyright © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals Inc.

  13. An in-line spectrophotometer on a centrifugal microfluidic platform for real-time protein determination and calibration.

    Science.gov (United States)

    Ding, Zhaoxiong; Zhang, Dongying; Wang, Guanghui; Tang, Minghui; Dong, Yumin; Zhang, Yixin; Ho, Ho-Pui; Zhang, Xuping

    2016-09-21

    In this paper, an in-line, low-cost, miniature and portable spectrophotometric detection system is presented and used for fast protein determination and calibration in centrifugal microfluidics. Our portable detection system is configured with paired emitter and detector diodes (PEDD), where the light beam between both LEDs is collimated with enhanced system tolerance. It is the first time that a physical model of PEDD is clearly presented, which could be modelled as a photosensitive RC oscillator. A portable centrifugal microfluidic system that contains a wireless port in real-time communication with a smartphone has been built to show that PEDD is an effective strategy for conducting rapid protein bioassays with detection performance comparable to that of a UV-vis spectrophotometer. The choice of centrifugal microfluidics offers the unique benefits of highly parallel fluidic actuation at high accuracy while there is no need for a pump, as inertial forces are present within the entire spinning disc and accurately controlled by varying the spinning speed. As a demonstration experiment, we have conducted the Bradford assay for bovine serum albumin (BSA) concentration calibration from 0 to 2 mg mL(-1). Moreover, a novel centrifugal disc with a spiral microchannel is proposed for automatic distribution and metering of the sample to all the parallel reactions at one time. The reported lab-on-a-disc scheme with PEDD detection may offer a solution for high-throughput assays, such as protein density calibration, drug screening and drug solubility measurement that require the handling of a large number of reactions in parallel.

  14. Analyzing Protein Denaturation using Fast Differential Scanning Calorimetry

    NARCIS (Netherlands)

    Splinter, R.; Van Herwaarden, A.W.; Iervolino, E.; Vanden Poel, G.; Istrate, D.; Sarro, P.M.

    2012-01-01

    This paper investigates the possibility to measure protein denaturation with Fast Differential Scanning Calorimetry (FDSC). Cancer can be diagnosed by measuring protein denaturation in blood plasma using Differential Scanning Calorimetry (DSC). FDSC can reduce diagnosis time from hours to minutes,

  15. Detection of outliers in gas centrifuge experimental data

    International Nuclear Information System (INIS)

    Andrade, Monica C.V.; Nascimento, Claudio A.O.

    2005-01-01

    Isotope separation in a gas centrifuge is a very complex process. Development and optimization of a gas centrifuge requires experimentation. These data contain experimental errors, and like other experimental data, there may be some gross errors, also known as outliers. The detection of outliers in gas centrifuge experimental data may be quite complicated because there is not enough repetition for precise statistical determination and the physical equations may be applied only on the control of the mass flows. Moreover, the concentrations are poorly predicted by phenomenological models. This paper presents the application of a three-layer feed-forward neural network to the detection of outliers in a very extensive experiment for the analysis of the separation performance of a gas centrifuge. (author)

  16. Quantification of platelets obtained by different centrifugation protocols in SHR rats

    OpenAIRE

    João Alberto Yazigi Junior; João Baptista Gomes dos Santos; Bruno Rodrigues Xavier; Marcela Fernandes; Sandra Gomes Valente; Vilnei Mattiolli Leite

    2015-01-01

    ABSTRACT OBJECTIVE: To quantify the platelet concentration in the blood of SHR rats, by means of different centrifugation protocols, and to evaluate what the most effective method for obtaining platelets is. METHODS: We used 40 male rats of the isogenic SHR lineage. The animals were divided into three groups: control, using whole blood without centrifugation; single centrifugation, using whole blood subjected to a single centrifugation at 200 × gand 400 × g; and double centrifugation, usin...

  17. The impact of the centrifuge characteristics and centrifugation protocols on the cells, growth factors, and fibrin architecture of a leukocyte- and platelet-rich fibrin (L-PRF) clot and membrane.

    Science.gov (United States)

    Dohan Ehrenfest, David M; Pinto, Nelson R; Pereda, Andrea; Jiménez, Paula; Corso, Marco Del; Kang, Byung-Soo; Nally, Mauricio; Lanata, Nicole; Wang, Hom-Lay; Quirynen, Marc

    2018-03-01

    L-PRF (leukocyte- and platelet-rich fibrin) is one of the four families of platelet concentrates for surgical use and is widely used in oral and maxillofacial regenerative therapies. The first objective of this article was to evaluate the mechanical vibrations appearing during centrifugation in four models of commercially available table-top centrifuges used to produce L-PRF and the impact of the centrifuge characteristics on the cell and fibrin architecture of a L-PRF clot and membrane. The second objective of this article was to evaluate how changing some parameters of the L-PRF protocol may influence its biological signature, independently from the characteristics of the centrifuge. In the first part, four different commercially available centrifuges were used to produce L-PRF, following the original L-PRF production method (glass-coated plastic tubes, 400 g force, 12 minutes). The tested systems were the original L-PRF centrifuge (Intra-Spin, Intra-Lock, the only CE and FDA cleared system for the preparation of L-PRF) and three other laboratory centrifuges (not CE/FDA cleared for L-PRF): A-PRF 12 (Advanced PRF, Process), LW-UPD8 (LW Scientific) and Salvin 1310 (Salvin Dental). Each centrifuge was opened for inspection, two accelerometers were installed (one radial, one vertical), and data were collected with a spectrum analyzer in two configurations (full-load or half load). All clots and membranes were collected into a sterile surgical box (Xpression kit, Intra-Lock). The exact macroscopic (weights, sizes) and microscopic (photonic and scanning electron microscopy SEM) characteristics of the L-PRF produced with these four different machines were evaluated. In the second part, venous blood was taken in two groups, respectively, Intra-Spin 9 ml glass-coated plastic tubes (Intra-Lock) and A-PRF 10 ml glass tubes (Process). Tubes were immediately centrifuged at 2700 rpm (around 400 g) during 12 minutes to produce L-PRF or at 1500 rpm during 14 minutes to produce A

  18. Centrifuge modelling - migration of radionuclides from engineered trenches

    International Nuclear Information System (INIS)

    Dean, E.T.R.; Schofield, A.N.

    1991-12-01

    This report provides an overview of some centrifuge small-scale physical model tests and 1g experimental and theoretical work relating to the sub-surface migration of a model pollutant (sodium chloride) from a notional prototype surface landfill of width 25 metres and depth 3 metres cut into a 20 metre deep layer of nominally uniform soil overlying a more permeable base layer. An introduction is given to the application of geotechnical centrifuge modelling techniques to pollutant migration studies. Experiments performed at 1/100th scale using the Cambridge 10 metre diameter Geotechnical Beam Centrifuge simulating transport through silt over prototype time periods of around 35 years, are summarised. Comparisons of data with calculations using early versions of the POLLUTE and MIGRATE computer codes are presented. An experiment at 1/400th scale using the new Cambridge Geotechnical Drum Centrifuge, involving transport through clay over a prototype time period of around 1000 years, is described. Potential future uses of centrifuge modelling techniques to simulate long-term migration through more complex hydrological environments are also discussed. (author)

  19. Use of the TFTR prototype charge exchange neutral analyzer for fast He3++ diagnostics during ICRF heating on PLT

    International Nuclear Information System (INIS)

    Medley, S.S.

    1981-07-01

    The Charge Exchange Neutral Analyzer (CENA) for TFTR is designed to measure singly charged ion species of atomic mass A = 1, 2, and 3 simultaneously with up to 75 energy channels per mass and an energy range of 0.5 3 charge exchange neutrals makes the analyzer of particular interest for recently proposed fast He 3 ++ diagnostics during ICRF heating on PLT

  20. Effect of science laboratory centrifuge of space station environment

    Science.gov (United States)

    Searby, Nancy

    1990-01-01

    It is argued that it is essential to have a centrifuge operating during manned space station operations. Background information and a rationale for the research centrifuge are given. It is argued that we must provide a controlled acceleration environment for comparison with microgravity studies. The lack of control groups in previous studies throws into question whether the obseved effects were the result of microgravity or not. The centrifuge could be used to provide a 1-g environment to supply specimens free of launch effects for long-term studies. With the centrifuge, the specimens could be immediately transferred to microgravity without undergoing gradual acclimation. Also, the effects of artificial gravity on humans could be investigated. It is also argued that the presence of the centrifuge on the space station will not cause undo vibrations or other disturbing effects.

  1. Prediction of active control of subsonic centrifugal compressor rotating stall

    Science.gov (United States)

    Lawless, Patrick B.; Fleeter, Sanford

    1993-01-01

    A mathematical model is developed to predict the suppression of rotating stall in a centrifugal compressor with a vaned diffuser. This model is based on the employment of a control vortical waveform generated upstream of the impeller inlet to damp weak potential disturbances that are the early stages of rotating stall. The control system is analyzed by matching the perturbation pressure in the compressor inlet and exit flow fields with a model for the unsteady behavior of the compressor. The model was effective at predicting the stalling behavior of the Purdue Low Speed Centrifugal Compressor for two distinctly different stall patterns. Predictions made for the effect of a controlled inlet vorticity wave on the stability of the compressor show that for minimum control wave magnitudes, on the order of the total inlet disturbance magnitude, significant damping of the instability can be achieved. For control waves of sufficient amplitude, the control phase angle appears to be the most important factor in maintaining a stable condition in the compressor.

  2. Numerical Study on Dynamic Response of Pile Group Foundation of Geotechnical Centrifuge

    Directory of Open Access Journals (Sweden)

    Mao Quansheng

    2015-01-01

    Full Text Available Based on National Engineering Laboratory for Harbor Engineering Structure-Geotechnical Centrifuge Laboratory construction project, the dynamical response of piles foundation under horizontal-rocking vibration was analyzed by using finite element software Abaqus, and the displacement and stress characteristics of piles were discussed with soil between the piles reinforced by high pressure jet piles. The result indicates that in the operation of the centrifuge, foundation changes of vertical load of center pile are very small; the vertical displacement of the pile head is increasing, the vertical displacement of the pile head is no longer changed until the vibration time reaches 3 times period,; the horizontal load of piles varies with sinusoidal, the horizontal displacement amplitude is increasing, , and the vibration amplitude reaches to fixed value at 2 times vibration period.

  3. Forces on Centrifugal Pump Impellers

    OpenAIRE

    Jery, Belgacem; Brennen, Christopher E.; Caughey, Thomas K.; Acosta, Allan

    1985-01-01

    Forces are exerted on a centrifugal pump impeller, due to the asymmetry of the flow caused by the volute of diffuser, and to the motion of the center of the impeller whenever the shaft whirls. Recent work in the measurement of these forces as a function of the whirl speed to shaft speed ratio, and the influence of the volute, is reviewed. These forces may be decomposed into a steady force, a static stiffness matrix, a damping matrix and an inertia matrix. It is shown that for centrifugal p...

  4. Centrifuge modelling of contaminant transport processes

    OpenAIRE

    Culligan, P. J.; Savvidou, C.; Barry, D. A.

    1996-01-01

    Over the past decade, research workers have started to investigate problems of subsurface contaminant transport through physical modelling on a geotechnical centrifuge. A major advantage of this apparatus is its ability to model complex natural systems in a controlled laboratory environment In this paper, we discusses the principles and scaling laws related to the centrifugal modelling of contaminant transport, and presents four examples of recent work that has bee...

  5. Analysis of cavitation behaviour in a centrifugal pump

    International Nuclear Information System (INIS)

    He, M; Zhou, L J; Guo, Q; Fu, L P; Wang, Z W

    2012-01-01

    Cavitation is a well-known problem in centrifugal pumps, causing serious damage and substantial head losses. However, the reason for the sudden head drop in cavitation curves is not fully understood. In this paper, the transient three-dimensional cavitating flow field in a centrifugal pump was calculated using RNG k-ε turbulence model and Rayleigh Plesset cavitation model. The NPSH-H curve and the cavitation development in the whole passage were predicted. The blade loading and energy transfer are analyzed for various cavitation conditions. The results show that the existing of the cavities changes the load distribution on blades. With the decrease of NPSH the loads on blades tend to increases in the rear part but decreases in the front part. If NPSH is not so low, sometimes the overall torque may increase slightly, thus the head may also increase slightly. But if the NPSH become low and reach a threshold value, the overall torque will also decrease. At the same time, the energy dissipation in the vortices increases greatly because of the growth of the cavities. These two reasons make the head drop rapidly.

  6. Flow induced vibrations in gas tube assembly of centrifuge

    International Nuclear Information System (INIS)

    Alam, M.; Atta, M.A.; Mirza, J.A.; Khan, A.Q.

    1986-01-01

    A centrifuge essentially consists of a rotor rotating at very high speed. Gas tube assembly, located at the center of the rotor, is used to introduce feed gas into the rotor and remove product and waste streams from it. The gas tube assembly is thus a static component, the product and waste scoops of which are lying in the high pressure region of a fluid rotating at very high speed. This can cause flow induced vibrations in the gas tube assembly. Such vibrations affect not only the mechanical stability of the gas tube assembly but may also reduce the separative power of the centrifuge. In a cascade, if some of the centrifuges have gas tube vibration, then cascade performance will be affected. A theoretical analysis of the effect of waste tube vibrations on product and waste flow rates and pressures in the centrifuge is presented. A simple stage consisting of two centrifuges, in which one has tube vibration, is considered for this purpose. The results are compared with experiment. It is shown that waste tube vibration generates oscillations in waste and product flow rates that are observable outside the centrifuge. (author)

  7. Direct Monte-Carlo Siumulations In a Gas Centrifuge

    National Research Council Canada - National Science Library

    Roblin, Philippe

    2000-01-01

    The study is related to the centrifugation process for isotope separation. In a gas centrifuge, the major part of the rotating gas is modeled by fluid equations with this gas flow described by suitable Navier-Stokes...

  8. Egg beater as centrifuge: isolating human blood plasma from whole blood in resource-poor settings.

    Science.gov (United States)

    Wong, Amy P; Gupta, Malancha; Shevkoplyas, Sergey S; Whitesides, George M

    2008-12-01

    This paper demonstrates that a hand-powered egg beater can be modified to serve as a centrifuge for separating plasma from human whole blood. Immunoassays used to diagnose infectious diseases often require plasma from whole blood, and obtaining plasma typically requires electrically-powered centrifuges, which are not widely available in resource-limited settings. Human whole blood was loaded into polyethylene (PE) tubing, and the tubing was attached to the paddle of an egg beater. Spinning the paddle pelleted the blood cells to the distal end of the PE tubing; the plasma remained as the supernatant. A cholesterol assay (run on patterned paper) demonstrated the suitability of this plasma for use in diagnostic assays. The physics of the system was also analyzed as a guide for the selection of other rotating systems for use in centrifugation. Egg beaters, polyethylene tubing, and paper are readily available devices and supplies that can facilitate the use of point-of-care diagnostics at sites far from centralized laboratory facilities.

  9. Gas centrifuge uranium enrichment programme in the United States of America

    International Nuclear Information System (INIS)

    Gestson, D.K.

    1983-01-01

    The technology of uranium enrichment using the gas centrifuge is fully proven as a result of over twenty years of research. The high performance of the centrifuge has been confirmed, and its reliability established, through detailed evaluation of a series of centrifuge designs. The baseline centrifuge for the Gas Centrifuge Enrichment Plant (GCEP) is now in commercial production by three qualified manufacturers. It will be ready for installation in GCEP on schedule. The GCEP construction is also on schedule, with two process buildings expected to start operation in 1988 and 1989. Development and demonstration of the Set IV advanced gas centrifuge is under way and it is expected to be ready for installation in Process Building 3 in early 1989. (author)

  10. Numerical simulation of the unsteady progress in centrifuge

    International Nuclear Information System (INIS)

    Wei Chunlin; Zeng Shi

    2006-01-01

    Unsteady flow equations for the centrifuge are solved on a staggered grid by a finite volume method. The transient process that the axial flow in the centrifuge is established under a steady thermal driving. It can be concluded that the influence which causes the perturbing fluid is different at the beginning and the end of the processing. The flow is caused by the imbalance of temperature which turns to be caused by the imbalance of pressure. The results show that the numerical simulation is effective at the unsteady fluid in a centrifuge. (authors)

  11. 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.

    2017-01-01

    A centrifugal compressor research effort conducted by United Technologies Research Center under NASA Research Announcement NNC08CB03C is documented. The objectives were to identify key technical barriers to advancing the aerodynamic performance of high-efficiency, high work factor, compact centrifugal compressor aft-stages for turboshaft engines; to acquire measurements needed to overcome the technical barriers and inform future designs; to design, fabricate, and test a new research compressor in which to acquire the requisite flow field data. A new High-Efficiency Centrifugal Compressor stage -- splittered impeller, splittered diffuser, 90 degree bend, and exit guide vanes -- with aerodynamically aggressive performance and configuration (compactness) goals were designed, fabricated, and subquently tested at the NASA Glenn Research Center.

  12. Separative properties of counter-current beams type centrifuge, (2)

    International Nuclear Information System (INIS)

    Todo, Fukuzo

    1975-01-01

    One-time through scheme is studied, which would produce the highest overall centrifuge efficiency among the three different flow schemes of enriching, stripping and one-time through. If the ''optimum concentration method'' is applied to the one-time through centrifuge, the machine will be able to obtain a very high efficiency at small gas flow rates. A proposed arrangement of centrifuges for this method is shown. The efficiency of this method will be more than 15--20% higher than obtainable with enriching scheme. When the radial gas flow rate near the end caps in the rotor is increased to about 10% of the total gas feed rate, the efficiency was found to decrease by only 1%. The efficiency appears to be almost independent of small amounts of refluxing gas flow. Since a separation method having a high efficiency at small gas flow rates is required for large-scale gas centrifuge plants, the one-time through centrifuge is promising, provided the optimum concentration method is adopted. (auth.)

  13. LISSAT Analysis of a Generic Centrifuge Enrichment Plant

    International Nuclear Information System (INIS)

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

    2007-01-01

    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

  14. Evaluation of a reduced centrifugation time and higher centrifugal force on various general chemistry and immunochemistry analytes in plasma and serum.

    Science.gov (United States)

    Møller, Mette F; Søndergaard, Tove R; Kristensen, Helle T; Münster, Anna-Marie B

    2017-09-01

    Background Centrifugation of blood samples is an essential preanalytical step in the clinical biochemistry laboratory. Centrifugation settings are often altered to optimize sample flow and turnaround time. Few studies have addressed the effect of altering centrifugation settings on analytical quality, and almost all studies have been done using collection tubes with gel separator. Methods In this study, we compared a centrifugation time of 5 min at 3000 ×  g to a standard protocol of 10 min at 2200 ×  g. Nine selected general chemistry and immunochemistry analytes and interference indices were studied in lithium heparin plasma tubes and serum tubes without gel separator. Results were evaluated using mean bias, difference plots and coefficient of variation, compared with maximum allowable bias and coefficient of variation used in laboratory routine quality control. Results For all analytes except lactate dehydrogenase, the results were within the predefined acceptance criteria, indicating that the analytical quality was not compromised. Lactate dehydrogenase showed higher values after centrifugation for 5 min at 3000 ×  g, mean bias was 6.3 ± 2.2% and the coefficient of variation was 5%. Conclusions We found that a centrifugation protocol of 5 min at 3000 ×  g can be used for the general chemistry and immunochemistry analytes studied, with the possible exception of lactate dehydrogenase, which requires further assessment.

  15. Modelling of hydrothermal characteristics of centrifugal nozzles

    International Nuclear Information System (INIS)

    Yarkho, A.A.; Omelchenko, M.P.; Borshchev, V.A.

    1990-01-01

    Presented for the first time is a method of recalculating the hydrothermal characteristics of centrifugal nozzles obtained in laboratory conditions for full-scale nozzles. From the experimental hydrothermal characteristics of nozzles observed in the laboratory it is allowed to calculate the hydrothermal characteristics of any other centrifugal nozzle whose diameter and dimensionless geometric characteristic are known

  16. Astronaut Gordon Cooper in centrifuge for tests

    Science.gov (United States)

    1963-01-01

    Astronaut L. Gordon Cooper, prime pilot for the Mercury-Atlas 9 mission, is strapped into the gondola while undergoing tests in the centrifuge at the Naval Air Development Center, Johnsville, Pennsylvania. The centrifuge is used to investigate by simulation the pilot's capability to control the vehicle during the actual flight in its booster and reentry profile.

  17. Physical simulations using centrifuge techniques

    International Nuclear Information System (INIS)

    Sutherland, H.J.

    1981-01-01

    Centrifuge techniques offer a technique for doing physical simulations of the long-term mechanical response of deep ocean sediment to the emplacement of waste canisters and to the temperature gradients generated by them. Preliminary investigations of the scaling laws for pertinent phenomena indicate that the time scaling will be consistent among them and equal to the scaling factor squared. This result implies that this technique will permit accelerated-life-testing of proposed configurations; i.e, long-term studies may be done in relatively short times. Presently, existing centrifuges are being modified to permit scale model testing. This testing will start next year

  18. 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.

  19. Relativistic centrifugal instability

    Science.gov (United States)

    Gourgouliatos, Konstantinos N.; Komissarov, Serguei S.

    2018-03-01

    Near the central engine, many astrophysical jets are expected to rotate about their axis. Further out they are expected to go through the processes of reconfinement and recollimation. In both these cases, the flow streams along a concave surface and hence, it is subject to the centrifugal force. It is well known that such flows may experience the centrifugal instability (CFI), to which there are many laboratory examples. The recent computer simulations of relativistic jets from active galactic nuclei undergoing the process of reconfinement show that in such jets CFI may dominate over the Kelvin-Helmholtz instability associated with velocity shear (Gourgouliatos & Komissarov). In this letter, we generalize the Rayleigh criterion for CFI in rotating fluids to relativistic flows using a heuristic analysis. We also present the results of computer simulations which support our analytic criterion for the case of an interface separating two uniformly rotating cylindrical flows. We discuss the difference between CFI and the Rayleigh-Taylor instability in flows with curved streamlines.

  20. Considerations on safeguards approach for small centrifuge enrichment facilities

    International Nuclear Information System (INIS)

    Vicens, Hugo E.; Marzo, Marco A.; Nunes, Vitorio E.

    2004-01-01

    The safeguards' objectives for enrichment facilities encompass the detection of the diversion of declared nuclear material and of facility misuse. The safeguard's approach presently applied for commercial centrifuge enrichment facilities is based on the Hexa partite Project and seems not to be directly applicable to cases of small plants. Since ABACC started its operation one of the main problems faced was the application of safeguards to small centrifuge enrichment plants for testing centrifuges in cascade mode or for small LEU production. These plants consist of a few fully independent cascades, does not operate in a routine basis and panels prevent visual access to the centrifuges and their surroundings for preserving sensitive information. For such plants misuse scenarios seems to dominate, particularly those associated with feeding the plant with undeclared LEU. This paper presents a concise analysis of misuse strategies in small centrifuge facility and alternative safeguard's approach, describing the main control elements to be applied. The particularities arising from the existence of panels or boxes covering the centrifuges are specifically addressed. Two alternatives approaches based on the application of a transitory perimeter control to increase the effectiveness of unannounced inspection and on the application of permanent perimeter control are presented. (author)

  1. A Fast Calculation Method for Analyzing the Effect of Wind Generation on ATC

    Directory of Open Access Journals (Sweden)

    M.A Armin

    2015-12-01

    Full Text Available Wind energy penetration in power system has been increased very fast and large amount of capitals invested for wind farms all around the world. Meanwhile, in power systems with wind turbine generators (WTGs, the value of Available transfer capability (ATC is influenced by the probabilistic nature of the wind power. The Mont Carlo Simulation (MCS is the most common method to model the uncertainty of WTG. However, the MCS method suffers from low convergence rate. To overcome this shortcoming, the proposed technique in this paper uses a new formulation for solving ATC problem analytically. This lowers the computational burden of the ATC computation and hence results in increased convergence rate of the MCS. Using this fast technique to evaluate the ATC, wind generation and load correlation is required to get into modeling. A numerical method is presented to consider load and wind correlation. The proposed method is tested on the modified IEEE 118 bus to analyze the impacts of the WTGs on the ATC. The obtained results show that wind generation capacity and its correlation with system load has significant impacts on the network transfer capability. In other words, ATC probability distribution is sensitive to the wind generation capacity.

  2. Design and construction of a two-stage centrifugal pump | Nordiana ...

    African Journals Online (AJOL)

    Centrifugal pumps are widely used in moving liquids from one location to another in homes, offices and industries. Due to the ever increasing demand for centrifugal pumps it became necessary to design and construction of a two-stage centrifugal pump. The pump consisted of an electric motor, a shaft, two rotating impellers ...

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

    Science.gov (United States)

    2015-02-01

    3  FIGURE 5: PHOTO & PERFORMANCE PLOT OF EXISTING CENTRIFUGAL COMPRESSOR ...aerodynamically similar to an existing centrifugal compressor pictured in Figure 5. The performance plot of this compressor demonstrates a high...blade tip diameter at impeller exit Figure 5: Photo & Performance plot of existing centrifugal compressor 70% 75% 65% 60%   6

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

    International Nuclear Information System (INIS)

    Jiang, Hongmin; Lei, Zengguang; Zhuge, Fu

    2008-01-01

    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)

  5. DEM simulation of granular flows in a centrifugal acceleration field

    Science.gov (United States)

    Cabrera, Miguel Angel; Peng, Chong; Wu, Wei

    2017-04-01

    The main purpose of mass-flow experimental models is abstracting distinctive features of natural granular flows, and allow its systematic study in the laboratory. In this process, particle size, space, time, and stress scales must be considered for the proper representation of specific phenomena [5]. One of the most challenging tasks in small scale models, is matching the range of stresses and strains among the particle and fluid media observed in a field event. Centrifuge modelling offers an alternative to upscale all gravity-driven processes, and it has been recently employed in the simulation of granular flows [1, 2, 3, 6, 7]. Centrifuge scaling principles are presented in Ref. [4], collecting a wide spectrum of static and dynamic models. However, for the case of kinematic processes, the non-uniformity of the centrifugal acceleration field plays a major role (i.e., Coriolis and inertial effects). In this work, we discuss a general formulation for the centrifugal acceleration field, implemented in a discrete element model framework (DEM), and validated with centrifuge experimental results. Conventional DEM simulations relate the volumetric forces as a function of the gravitational force Gp = mpg. However, in the local coordinate system of a rotating centrifuge model, the cylindrical centrifugal acceleration field needs to be included. In this rotating system, the centrifugal acceleration of a particle depends on the rotating speed of the centrifuge, as well as the position and speed of the particle in the rotating model. Therefore, we obtain the formulation of centrifugal acceleration field by coordinate transformation. The numerical model is validated with a series of centrifuge experiments of monodispersed glass beads, flowing down an inclined plane at different acceleration levels and slope angles. Further discussion leads to the numerical parameterization necessary for simulating equivalent granular flows under an augmented acceleration field. The premise of

  6. Quantum versus classical dynamics in the optical centrifuge

    Science.gov (United States)

    Armon, Tsafrir; Friedland, Lazar

    2017-09-01

    The interplay between classical and quantum-mechanical evolution in the optical centrifuge (OC) is discussed. The analysis is based on the quantum-mechanical formalism starting from either the ground state or a thermal ensemble. Two resonant mechanisms are identified, i.e., the classical autoresonance and the quantum-mechanical ladder climbing, yielding different dynamics and rotational excitation efficiencies. The rotating-wave approximation is used to analyze the two resonant regimes in the associated dimensionless two-parameter space and calculate the OC excitation efficiency. The results show good agreement between numerical simulations and theory and are relevant to existing experimental setups.

  7. Results from uranium deposition studies for development of a Limited Frequency-Unannounced Access (LFUA) inspection strategy for gas centrifuge enrichment plants

    International Nuclear Information System (INIS)

    Cooley, J.N.; Fields, L.W.; Swindle, D.W.

    1985-06-01

    Uranium deposition studies were performed on a test loop system designed to simulate process gas flow through the header piping of a gas centrifuge enrichment plant. The objectives of these studies were to investigate the effectiveness of an in-line gaseous cleaning agent in removing uranium in pipe deposits and to analyze long-term deposition growth and isotopic exchange under simulated centrifuge plant operating conditions. The test loop studies are described, the results are reported, and the implications for analyzing actual plant data are discussed. Results indicate that: 93% of the uranium deposit is removed within 15 min when a pipe is pressurized with gaseous ClF 3 ; the isotopic abundance of a highly enriched uranium deposit remains unchanged when UF 6 of a lower assay is introduced into the pipe; and air inleakage will be the cause of the largest deposits in centrifuge plant process header pipes. 3 refs., 3 figs., 3 tabs

  8. Numerical analysis of flow in ultra micro centrifugal compressor -influence of meridional configuration

    Science.gov (United States)

    Kaneko, Masanao; Tsujita, Hoshio; Hirano, Toshiyuki

    2013-04-01

    A single stage ultra micro centrifugal compressor constituting ultra micro gas turbine is required to operate at high rotational speed in order to achieve the pressure ratio which establishes the gas turbine cycle. As a consequence, the aerodynamic losses can be increased by the interaction of a shock wave with the boundary layer on the blade surface. Moreover, the centrifugal force which exceeds the allowable stress of the impeller material can act on the root of blades. On the other hand, the restrictions of processing technology for the downsizing of impeller not only relatively enlarge the size of tip clearance but also make it difficult to shape the impeller with the three-dimensional blade. Therefore, it is important to establish the design technology for the impeller with the two-dimensional blade which possesses the sufficient aerodynamic performance and enough strength to bear the centrifugal force caused by the high rotational speed. In this study, the flow in two types of impeller with the two-dimensional blade which have different meridional configuration was analyzed numerically. The computed results clarified the influence of the meridional configuration on the loss generations in the impeller passage.

  9. Microfluidic size separation of cells and particles using a swinging bucket centrifuge.

    Science.gov (United States)

    Yeo, Joo Chuan; Wang, Zhiping; Lim, Chwee Teck

    2015-09-01

    Biomolecular separation is crucial for downstream analysis. Separation technique mainly relies on centrifugal sedimentation. However, minuscule sample volume separation and extraction is difficult with conventional centrifuge. Furthermore, conventional centrifuge requires density gradient centrifugation which is laborious and time-consuming. To overcome this challenge, we present a novel size-selective bioparticles separation microfluidic chip on a swinging bucket minifuge. Size separation is achieved using passive pressure driven centrifugal fluid flows coupled with centrifugal force acting on the particles within the microfluidic chip. By adopting centrifugal microfluidics on a swinging bucket rotor, we achieved over 95% efficiency in separating mixed 20 μm and 2 μm colloidal dispersions from its liquid medium. Furthermore, by manipulating the hydrodynamic resistance, we performed size separation of mixed microbeads, achieving size efficiency of up to 90%. To further validate our device utility, we loaded spiked whole blood with MCF-7 cells into our microfluidic device and subjected it to centrifugal force for a mere duration of 10 s, thereby achieving a separation efficiency of over 75%. Overall, our centrifugal microfluidic device enables extremely rapid and label-free enrichment of different sized cells and particles with high efficiency.

  10. PARAMETRIC DIAGNOSTICS OF THE CENTRIFUGAL SUPERCHARGER'S TECHNICAL CONDITION DURING OPERATION

    Directory of Open Access Journals (Sweden)

    Regina A. Khuramshina

    2017-01-01

    Full Text Available Abstract. Objectives The main aim is to develop a mathematical model of a centrifugal compressor and carry out a parametric diagnostics of a centrifugal supercharger's technical condition during operation. Methods  A model is proposed for calculating the thermodynamic properties of natural gas, reducing the parameters of a centrifugal compressor to the initial conditions and to the rotation frequency, as well as the integral indicators of the supercharger's technical state. The technical state of the gas path of the centrifugal supercharger of the compressor unit is determined by the parametric diagnostic method. Results  The software implementation of the mathematical model of centrifugal compressor is carried out using a DVIGwT PC. The analysis of calculations indicates that the model is appropriate, with the error being due to taking into account the properties of iso-butane and i-hexane, in contrast with the VNIIGAZ technique. The evaluation studies of a centrifugal compressor's state are indicative of the presence or absence of its defects. Conclusion  Among a number of the diagnostic methods for evaluating a centrifugal supercharger, the most effective is vibrodiagnostics. However, the search for malfunctions and nascent defects in the flowing part of the centrifugal compressor cannot be limited only to vibrodiagnostic data, which provides about 60% of the reliable information about the state of the gas-air tract. About 20% of the compressor's malfunctions and approximately half of the dangerous modes of the supercharger's flow-through part is detected using thermogasdynamic parametric analysis (parametric diagnostics. The main difficulty of the control over the technical state of the flow-through part of the centrifugal supercharger is in the complication of the quantitative evaluation of the processes taking place in the supercharger, which leads to problems in providing reliable diagnosis during a reasonable period of time.

  11. Microcomputer-based instrument for the detection and analysis of precession motion in a gas centrifuge machine

    International Nuclear Information System (INIS)

    Paulus, S.S.

    1986-03-01

    The Centrifuge Precession Analyzer (CPA) is a microcomputer-based instrument which detects precession motion in a gas centrifuge machine and calculates the amplitude and frequency of precession. The CPA consists of a printed circuit board which contains signal-conditioning circuitry and a 24-bit counter and an INTEL iSBC 80-/24 single-board computer. Precession motion is detected by monitoring a signal generated by a variable reluctance pick-up coil in the top of the centrifuge machine. This signal is called a Fidler signal. The initial Fidler signal triggers a counter which is clocked by a high-precision, 20.000000-MHz, temperature-controlled, crystal oscillator. The contents of the counter are read by the computer, and the counter reset after every ten Fidler signals. The speed of the centrifuge machine and the amplitude and frequency of precession are calculated, and the results are displayed on a liquid crystal display on the front panel of the CPA. The thesis contains results from data generated by a Fidler signal simulator and data taken when the centrifuge was operated under three test conditions: (1) nitrogen gas during drive-up, steady state, and drive-down, (2) xenon gas during slip test, steady state, and the addition of gas, and (3) no gas during steady state. The qualitative results were consistent with experience with centrifuge machines UF 6 in that the amplitude of precession increased and the frequency of precession decreased during drive-up, drive-down and the slip check. The magnitude of the amplitude and frequency of precession were proportional to the molecular weight of the gases in steady state

  12. Cardiac arrhythmias during aerobatic flight and its simulation on a centrifuge.

    Science.gov (United States)

    Zawadzka-Bartczak, Ewelina K; Kopka, Lech H

    2011-06-01

    It is well known that accelerations during centrifuge training and during flight can provoke cardiac arrhythmias. Our study was designed to investigate both the similarities and differences between heart rhythm disturbances during flights and centrifuge tests. There were 40 asymptomatic, healthy pilots who performed two training flights and were also tested in a human centrifuge according to a program of rapid onset rate acceleration (ROR) and of centrifuge simulation of the actual acceleration experienced in flight (Simulation). During the flight and centrifuge tests ECG was monitored with the Holter method. ECG was examined for heart rhythm changes and disturbances. During flights, premature ventricular contractions (PVCs) were found in 25% of the subjects, premature supraventricular contractions (PSVCs) and PVCs with bigeminy in 5%, and pairs of PVCs in 2.5% of subjects. During the centrifuge tests, PVCs were experienced by 45% of the subjects, PSVCs and pairs of PVCs by 7.5%, and PVCs with bigeminy by 2.5%. Sinus bradycardia was observed during flights and centrifuge tests in 7.5% of subjects. Comparative evaluation of electrocardiographic records in military pilots during flights and centrifuge tests demonstrated that: 1) there were no clinically significant arrhythmias recorded; and 2) the frequency and kind of heart rhythm disturbances during aerobatic flight and its simulation on a centrifuge were not identical and did not occur repetitively in the same persons during equal phases of the tests.

  13. DOUBLE code simulations of emissivities of fast neutrals for different plasma observation view-lines of neutral particle analyzers on the COMPASS tokamak

    Science.gov (United States)

    Mitosinkova, K.; Tomes, M.; Stockel, J.; Varju, J.; Stano, M.

    2018-03-01

    Neutral particle analyzers (NPA) measure line-integrated energy spectra of fast neutral atoms escaping the tokamak plasma, which are a product of charge-exchange (CX) collisions of plasma ions with background neutrals. They can observe variations in the ion temperature T i of non-thermal fast ions created by additional plasma heating. However, the plasma column which a fast atom has to pass through must be sufficiently short in comparison with the fast atom’s mean-free-path. Tokamak COMPASS is currently equipped with one NPA installed at a tangential mid-plane port. This orientation is optimal for observing non-thermal fast ions. However, in this configuration the signal at energies useful for T i derivation is lost in noise due to the too long fast atoms’ trajectories. Thus, a second NPA is planned to be connected for the purpose of measuring T i. We analyzed different possible view-lines (perpendicular mid-plane, tangential mid-plane, and top view) for the second NPA using the DOUBLE Monte-Carlo code and compared the results with the performance of the present NPA with tangential orientation. The DOUBLE code provides fast-atoms’ emissivity functions along the NPA view-line. The position of the median of these emissivity functions is related to the location from where the measured signal originates. Further, we compared the difference between the real central T i used as a DOUBLE code input and the T iCX derived from the exponential decay of simulated energy spectra. The advantages and disadvantages of each NPA location are discussed.

  14. Optimization of Power Consumption for Centrifugation Process Based on Attenuation Measurements

    Science.gov (United States)

    Salim, M. S.; Abd Malek, M. F.; Sabri, Naseer; Omar, M. Iqbal bin; Mohamed, Latifah; Juni, K. M.

    2013-04-01

    The main objective of this research is to produce a mathematical model that allows decreasing the electrical power consumption of centrifugation process based on attenuation measurements. The centrifugation time for desired separation efficiency may be measured to determine the power consumed of laboratory centrifuge device. The power consumption is one of several parameters that affect the system reliability and productivity. Attenuation measurements of wave propagated through blood sample during centrifugation process were used indirectly to measure the power consumption of device. A mathematical model for power consumption was derived and used to modify the speed profile of centrifuge controller. The power consumption model derived based on attenuation measurements has successfully save the power consumption of centrifugation process keeping high separation efficiency. 18kW.h monthly for 100 daily time device operation had been saved using the proposed model.

  15. Optimization of Power Consumption for Centrifugation Process Based on Attenuation Measurements

    International Nuclear Information System (INIS)

    Salim, M S; Iqbal bin Omar, M; Malek, M F Abd; Mohamed, Latifah; Sabri, Naseer; Juni, K M

    2013-01-01

    The main objective of this research is to produce a mathematical model that allows decreasing the electrical power consumption of centrifugation process based on attenuation measurements. The centrifugation time for desired separation efficiency may be measured to determine the power consumed of laboratory centrifuge device. The power consumption is one of several parameters that affect the system reliability and productivity. Attenuation measurements of wave propagated through blood sample during centrifugation process were used indirectly to measure the power consumption of device. A mathematical model for power consumption was derived and used to modify the speed profile of centrifuge controller. The power consumption model derived based on attenuation measurements has successfully save the power consumption of centrifugation process keeping high separation efficiency. 18kW.h monthly for 100 daily time device operation had been saved using the proposed model.

  16. Probing molecular potentials with an optical centrifuge

    Science.gov (United States)

    Milner, A. A.; Korobenko, A.; Hepburn, J. W.; Milner, V.

    2017-09-01

    We use an optical centrifuge to excite coherent rotational wave packets in N2O, OCS, and CS2 molecules with rotational quantum numbers reaching up to J ≈465 , 690, and 1186, respectively. Time-resolved rotational spectroscopy at such ultra-high levels of rotational excitation can be used as a sensitive tool to probe the molecular potential energy surface at internuclear distances far from their equilibrium values. Significant bond stretching in the centrifuged molecules results in the growing period of the rotational revivals, which are experimentally detected using coherent Raman scattering. We measure the revival period as a function of the centrifuge-induced rotational frequency and compare it with the numerical calculations based on the known Morse-cosine potentials.

  17. Rotating stall simulation for axial and centrifugal compressors

    Science.gov (United States)

    Halawa, Taher; Gadala, Mohamed S.

    2017-05-01

    This study presents a numerical simulation of the rotating stall phenomenon in axial and centrifugal compressors with detailed descriptions of stall precursors and its development with time. Results showed that the vaneless region of the centrifugal compressor is the most critical location affected by stall. It was found that the tip leakage flow and the back flow impingement are the main cause of the stall development at the impeller exit area for centrifugal compressors. The results of the axial compressor simulations indicated that the early separated flow combined with the tip leakage flow can block the impeller passages during stall.

  18. Fluid dynamics and mass transfer in a gas centrifuge

    International Nuclear Information System (INIS)

    Conlisk, A.T.; Foster, M.R.; Walker, J.D.A.

    1982-01-01

    The fluid motion, temperature distribution and the mass-transfer problem of a binary gas mixture in a rapidly rotating centrifuge are investigated. Solutions for the velocity, temperature and mass-fraction fields within the centrifuge are obtained for mechanically or thermally driven centrifuges. For the mass-transfer problem, a detailed analysis of the fluid-mechanical boundary layers is required, and, in particular, mass fluxes within the boundary layers are obtained for a wide range of source-sink geometries. Solutions to the mass-transfer problem are obtained for moderately and strongly forced flows in the container; the dependence of the separation (or enrichment) factor on centrifuge configuration, rotational speed and fraction of the volumetric flow rate extracted at the product port (the cut) are predicted. (author)

  19. Experimental study on enriching 12C by centrifuge method

    International Nuclear Information System (INIS)

    Xiao Huaxian

    1994-07-01

    The diamond made from the highly enriched 12 C, whose thermal conductivity and electric insulativity are much better than that of natural diamond, has widely uses in new and high technology. In many enriching 12 C methods, the gas centrifuge method is superior to others. After selecting the appropriate process gas and solving key problems, such as feed and extract, the separation experiments are performed by a single stage of centrifuge. To increase the separation capacity of single machine, various parameters in the centrifugal separation are optimized, and appropriate mechanical drive, thermal drive, hold-up and process parameters are selected. The optimal operating condition of single machine is also obtained in the cascade. Thus, highly enriched 12 C is produced in the centrifuge cascade

  20. Convective instabilities in liquid centrifugation for nuclear wastes separation

    Energy Technology Data Exchange (ETDEWEB)

    Camassa, R. [Los Alamos National Laboratory, NM (United States)

    1995-10-01

    The separation of fission products from liquid solutions using centrifugal forces may prove an effective alternative to chemical processing in cases where radioactive materials necessitate minimal mixed-waste products or when allowing access to sophisticated chemical processing is undesirable. This investigation is a part of the effort to establish the feasibility of using liquid centrifugation for nuclear waste separation in the Accelerator Driven Energy Production (ADEP) program. A number of fundatmental issues in liquid centrifugation with radioactive elements need to be addressed in order to validate the approach and provide design criteria for experimental liquid salt (LiF and BeF{sub 2}) centrifuge. The author concentrates on one such issue, the possible onset of convective instabilities which could inhibit separation.

  1. 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.

  2. Human Powered Centrifuge

    Science.gov (United States)

    Mulenburg, Gerald M. (Inventor); Vernikos, Joan (Inventor)

    1997-01-01

    A human powered centrifuge has independently established turntable angular velocity and human power input. A control system allows excess input power to be stored as electric energy in a battery or dissipated as heat through a resistors. In a mechanical embodiment, the excess power is dissipated in a friction brake.

  3. Use of a centrifugation-based, point-of-care device for production of canine autologous bone marrow and platelet concentrates.

    Science.gov (United States)

    Thoesen, Michael S; Berg-Foels, Wendy S Vanden; Stokol, Tracy; Rassnick, Kenneth M; Jacobson, May S; Kevy, Sherwin V; Todhunter, Rory J

    2006-10-01

    To analyze a centrifugation-based, point-of-care device that concentrates canine platelets and bone marrow-derived cells. 19 adult sexually intact dogs. Anticoagulated peripheral blood (60 mL) and 60 mL of anticoagulated bone marrow aspirate (BMA) were concentrated by centrifugation with the centrifugation-based, point-of-care device to form a platelet and a bone marrow concentrate (BMC) from 11 dogs. Blood samples were analyzed on the basis of hemograms, platelet count, and PCV. The BMA and BMC were analyzed to determine PCV, total nucleated cell count, RBC count, and differential cell counts. The BMC stromal cells were cultured in an osteoinductive medium. Eight additional dogs were used to compare the BMC yield with that in which heparin was infused into the bone marrow before aspiration. The centrifugation-based, point-of-care device concentrated platelets by 6-fold over baseline (median recovery, 63.1%) with a median of 1,336 x 10(3) platelets/microL in the 7-mL concentrate. The nucleated cells in BMCs increased 7-fold (median recovery, 42.9%) with a median of 720 x 10(3) cells/microL in the 4-mL concentrate. The myeloid nucleated cells and mononuclear cells increased significantly in BMCs with a significant decrease in PCV, compared with that of BMAs. Stromal cell cultures expressed an osteoblastic phenotype in culture. Infusion of heparin into the bone marrow eliminated clot formation and created less variation in the yield (median recovery, 61.9%). Bone marrow-derived cell and platelet-rich concentrates may form bone if delivered in an engineered graft, thus decreasing the need for cancellous bone grafts.

  4. A fuzzy controlled three-phase centrifuge for waste separation

    International Nuclear Information System (INIS)

    Parkinson, W.J.; Smith, R.E.; Miller, N.

    1998-02-01

    The three-phase centrifuge technology discussed in this paper was developed by Neal Miller, president of Centech, Inc. The three-phase centrifuge is an excellent device for cleaning up oil field and refinery wastes which are typically composed of hydrocarbons, water, and solids. The technology is unique. It turns the waste into salable oil, reusable water, and landfill-able solids. No secondary waste is produced. The problem is that only the inventor can set up and run the equipment well enough to provide an optimal cleanup. Demand for this device has far exceeded a one man operation. There is now a need for several centrifuges to be operated at different locations at the same time. This has produced a demand for an intelligent control system, one that could replace a highly skilled operator, or at least supplement the skills of a less experienced operator. The control problem is ideally suited to fuzzy logic, since the centrifuge is a highly complicated machine operated entirely by the skill and experience of the operator. A fuzzy control system was designed for and used with the centrifuge

  5. Fabrication of Al/Diamond Particles Functionally Graded Materials by Centrifugal Sintered-Casting Method

    International Nuclear Information System (INIS)

    Watanabe, Yoshimi; Shibuya, Masafumi; Sato, Hisashi

    2013-01-01

    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. Quasi‐steady centrifuge method for unsaturated hydraulic properties

    Science.gov (United States)

    Caputo, Maria C.; Nimmo, John R.

    2005-01-01

    We have developed the quasi‐steady centrifuge (QSC) method as a variation of the steady state centrifuge method that can be implemented simply and inexpensively with greater versatility in terms of sample size and other features. It achieves these advantages by somewhat relaxing the criterion for steadiness of flow through the sample. This compromise entails an increase in measurement uncertainty but to a degree that is tolerable in most applications. We have tested this new approach with an easily constructed apparatus to establish a quasi‐steady flow of water in unsaturated porous rock samples spinning in a centrifuge, obtaining measurements of unsaturated hydraulic conductivity and water retention that agree with results of other methods. The QSC method is adaptable to essentially any centrifuge suitable for hydrogeologic applications, over a wide range of sizes and operating speeds. The simplified apparatus and greater adaptability of this method expands the potential for exploring situations that are common in nature but have been the subject of few laboratory investigations.

  7. Quasi-steady centrifuge method for unsaturated hydraulic properties

    Science.gov (United States)

    Caputo, Maria C.; Nimmo, John R.

    2005-11-01

    We have developed the quasi-steady centrifuge (QSC) method as a variation of the steady state centrifuge method that can be implemented simply and inexpensively with greater versatility in terms of sample size and other features. It achieves these advantages by somewhat relaxing the criterion for steadiness of flow through the sample. This compromise entails an increase in measurement uncertainty but to a degree that is tolerable in most applications. We have tested this new approach with an easily constructed apparatus to establish a quasi-steady flow of water in unsaturated porous rock samples spinning in a centrifuge, obtaining measurements of unsaturated hydraulic conductivity and water retention that agree with results of other methods. The QSC method is adaptable to essentially any centrifuge suitable for hydrogeologic applications, over a wide range of sizes and operating speeds. The simplified apparatus and greater adaptability of this method expands the potential for exploring situations that are common in nature but have been the subject of few laboratory investigations.

  8. New type of centrifugal extractor

    International Nuclear Information System (INIS)

    Miyauchi, T.; Tolich, A.

    1975-01-01

    The main principles of a centrifugal extractor design which can be used in the reprocessing of spent fuel with high degree of burning out are given. The extractor consists of two rotating coaxial cylinders. The contact of liquid phases is done in the circular space between the cylinders. By the cylinder rotating the phases are dispersed and the interface, as well as the extraction rate is increased. The given principles of the extractor design are realized in two simplified laboratory installations. The preliminary data obtained point out that much greater rates of the phases contact are achieved in centrifugal extractors than in extraction columns

  9. Centrifugation and the Manhattan Project

    Science.gov (United States)

    Reed, Cameron

    2009-05-01

    A study of U. S. Army Manhattan Engineer District documents reveals that consideration of centrifugation as a means of uranium enrichment during World War II was considerably more extensive than is commonly appreciated. By the time the centrifuge project was abandoned in early 1944 a full-scale prototype unit had been fabricated and tested at near-production speeds, enrichments of close to theoretically-expected levels had been demonstrated with pilot-plant units, and plans for production plants had been developed. This paper will review the history of this little-known aspect of the Project and examine the circumstances of how it came to be discontinued.

  10. 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.

  11. Tropic responses of Phycomyces sporangiophores to gravitational and centrifugal stimuli.

    Science.gov (United States)

    DENNISON, D S

    1961-09-01

    A low-speed centrifuge was used to study the tropic responses of Phycomyces sporangiophores in darkness to the stimulus of combined gravitational and centrifugal forces. If this stimulus is constant the response is a relatively slow tropic reaction, which persists for up to 12 hours. The response is accelerated by increasing the magnitude of the gravitational-centrifugal force. A wholly different tropic response, the transient response, is elicited by an abrupt change in the gravitational-centrifugal stimulus. The transient response has a duration of only about 6 min. but is characterized by a high bending speed (about 5 degrees /min.). An analysis of the distribution of the transient response along the growing zone shows that the active phase of the response has a distribution similar to that of the light sensitivity for the light-growth and phototropic responses. Experiments in which sporangiophores are centrifuged in an inert dense fluid indicate that the sensory mechanism of the transient response is closely related to the physical deformation of the growing zone caused by the action of the gravitational-centrifugal force on the sporangiophore as a whole. However, the response to a steady gravitational-centrifugal force is most likely not connected with this deformation, but is probably triggered by the shifting of regions or particles of differing density relative to one another inside the cell.

  12. Centrifuge separation effect on bacterial indicator reduction in dairy manure.

    Science.gov (United States)

    Liu, Zong; Carroll, Zachary S; Long, Sharon C; Roa-Espinosa, Aicardo; Runge, Troy

    2017-04-15

    Centrifugation is a commonly applied separation method for manure processing on large farms to separate solids and nutrients. Pathogen reduction is also an important consideration for managing manure. Appropriate treatment reduces risks from pathogen exposure when manure is used as soil amendments or the processed liquid stream is recycled to flush the barn. This study investigated the effects of centrifugation and polymer addition on bacterial indicator removal from the liquid fraction of manure slurries. Farm samples were taken from a manure centrifuge processing system. There were negligible changes of quantified pathogen indicator concentrations in the low-solids centrate compared to the influent slurry. To study if possible improvements could be made to the system, lab scale experiments were performed investigating a range of g-forces and flocculating polymer addition. The results demonstrated that polymer addition had a negligible effect on the indicator bacteria levels when centrifuged at high g forces. However, the higher g force centrifugation was capable of reducing bacterial indicator levels up to two-log 10 in the liquid stream of the manure, although at speeds higher than typical centrifuge operations currently used for manure processing applications. This study suggests manure centrifuge equipment could be redesigned to provide pathogen reduction to meet emerging issues, such as zoonotic pathogen control. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  13. The creation and research of the disk-type molecular pump above the top end of centrifuge

    International Nuclear Information System (INIS)

    Li Yunan; Dong Jinping

    2014-01-01

    Disk-type molecular pump placed above the top end of a centrifuge could improve the vacuum of the sleeve, as well as reduce the friction power consumption. This issue carries out a numerical simulation based on the model of molecular pump installed above the top end of centrifuge. The mathematical model is established and calculated by the Matlab program, studying the gas passageways of pump. The suction performance under the influence of gas passageways' geometric dimensions is analyzed, focusing on the effect of different shapes of side walls in the passageway. Design criterion of increasing the compression ratio of disk-type molecular pump is concluded from the analysis. (authors)

  14. A centrifuge CO2 pellet cleaning system

    International Nuclear Information System (INIS)

    Foster, C.A.; Fisher, P.W.; Nelson, W.D.; Schechter, D.E.

    1993-01-01

    Centrifuge-based cryogenic pellet accelerator technology, originally developed at Oak Ridge National Laboratory (ORNL) for the purpose of refueling fusion reactors with high-speed pellets of frozen deuterium/tritium,is now being developed as a method of cleaning without the use of conventional solvents. In these applications large quantities of pellets made of frozen CO 2 or argon are accelerated in a high-speed rotor. The accelerated pellet stream is used to clean or etch surfaces. The advantage of this system is that the spent pellets and debris resulting from the cleaning process can be filtered leaving only the debris for disposal. This paper discusses the centrifuge CO 2 pellet cleaning system, the physics model of the pellet impacting the surface, the centrifuge apparatus, and some initial cleaning and etching tests

  15. Investigation of CFD calculation method of a centrifugal pump with unshrouded impeller

    Science.gov (United States)

    Wu, Dazhuan; Yang, Shuai; Xu, Binjie; Liu, Qiaoling; Wu, Peng; Wang, Leqin

    2014-03-01

    Currently, relatively large errors are found in numerical results in some low-specific-speed centrifugal pumps with unshrouded impeller because the effect of clearances and holes are not accurately modeled. Establishing an accurate analytical model to improve performance prediction accuracy is therefore necessary. In this paper, a three-dimensional numerical simulation is conducted to predict the performance of a low-specific-speed centrifugal pump, and the modeling, numerical scheme, and turbulent selection methods are discussed. The pump performance is tested in a model pump test bench, and flow rate, head, power and efficiency of the pump are obtained. The effect of taking into consideration the back-out vane passage, clearance, and balance holes is analyzed by comparing it with experimental results, and the performance prediction methods are validated by experiments. The analysis results show that the pump performance can be accurately predicted by the improved method. Ignoring the back-out vane passage in the calculation model of unshrouded impeller is found to generate better numerical results. Further, the calculation model with the clearances and balance holes can obviously enhance the numerical accuracy. The application of disconnect interface can reduce meshing difficulty but increase the calculation error at the off-design operating point at the same time. Compared with the standard k-ɛ, renormalization group k-ɛ, and Spalart-Allmars models, the Realizable k-ɛ model demonstrates the fastest convergent speed and the highest precision for the unshrouded impeller flow simulation. The proposed modeling and numerical simulation methods can improve the performance prediction accuracy of the low-specific-speed centrifugal pumps, and the modeling method is especially suitable for the centrifugal pump with unshrouded impeller.

  16. 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.

  17. Deep-body temperature changes in rats exposed to chronic centrifugation.

    Science.gov (United States)

    Oyama, J.; Platt, W. T.; Holland, V. B.

    1971-01-01

    Deep-body temperature was monitored continuously by implant biotelemetry in unrestrained rats before, during, and after exposure to prolonged and almost continuous centrifugation. Rats subjected to centrifugation for the first time at various G loads ranging up to 2.5 G show a rapid and significant fall in temperature which is sustained below normal levels for periods as long as 3 days. The magnitude of the temperature fall and the recovery time were generally proportional to the G load imposed. The initial fall and recovery of body temperature closely parallels the decrease in food consumption and to a lesser degree the decrease in body mass experienced by centrifuged rats. After exposure to 2 weeks of centrifugation, rats show either no change or only a small transient increase in temperature when decelerated to a lower G level or when returned to normal gravity. Rats repeatedly exposed to centrifugation consistently showed a smaller temperature response compared to the initial exposure. Implant temperature biotelemetry has been found to be a sensitive, reliable, and extremely useful technique for assessing the initial stress of centrifugation and in monitoring the time course of recovery and acclimation of rats to increase as well as*decrease G.

  18. Centrifugal compressor case study

    Energy Technology Data Exchange (ETDEWEB)

    Eckert, B.

    2010-10-15

    Three centrifugal compressors at a pipeline station were retrofitted with higher head impellers in 2008. The owners of the station experienced vibration problems over the following 2 years that caused transmitter and position failures that were assumed to be flow-induced pulsations. A vibration and pulsation analysis indicated that the shell mode piping vibration excited by the blade pass pulsation was responsible for the failures. This study outlined factors that contributed to the vibration problem. Interferences between the compressor and shell mode piping natural frequencies were predicted, and potential excitation sources were examined. The study demonstrated how centrifugal vibration analyses can be used during the design phase to avoid costly adjustments. Recommendations included the addition of stiffeners to alter the shell modes, and the addition of constrained layer damping material to reduce resonant responses. 2 refs., 1 tab., 12 figs.

  19. The fluid–solid coupling analysis of screw conveyor in drilling fluid centrifuge based on ANSYS

    Directory of Open Access Journals (Sweden)

    Hongbin Liu

    2015-09-01

    Full Text Available In the centrifugal separations of drilling fluid, screw conveyor is a critical component to push and separate the sediment. The work performance and structural parameters of conveyor are immediately related to the production capability, the working life and the separating effect of the centrifuge. The existing researches always use the theoretical calculation of the approximate loads to analyze the strength of conveyor, and it cannot reflect the stress situations accurately. In order to ensure the precise mastery of the working performance, this article obtained pressure distribution under working conditions from CFX evaluation and gained equivalent stress and deformation under several load conditions by using the ANSYS Workbench platform to check the strength of conveyor. The results showed that the influence of centrifugal hydraulic pressure was less than that of centrifugal force on the strength and deformation of conveyor. Besides, the maximum equivalent stress occurred at the inside of the feed opening, while the maximum deformation occurred at the conveyor blade edge of taper extremity. Furthermore, whether considered the feed opening or not, the computing model had a great influence on the analysis results, and the simplified loads had a great influence on the deformation analysis results. The methods and results from this article can provide reference for the design and the improvement of screw conveyor.

  20. Investigation on Flow-Induced Noise due to Backflow in Low Specific Speed Centrifugal Pumps

    Directory of Open Access Journals (Sweden)

    Qiaorui Si

    2013-01-01

    Full Text Available Flow-induced noise causes disturbances during the operation of centrifugal pumps and also affects their performance. The pumps often work at off-design conditions, mainly at part-load conditions, because of frequent changes in the pump device system. Consequently numerous unstable phenomena occur. In low specific speed centrifugal pumps the main disturbance is the inlet backflow, which is considered as one of the most important factors of flow-induced noise and vibration. In this study, a test rig of the flow-induced noise and vibration of the centrifugal pump was built to collect signals under various operating conditions. The three-dimensional unsteady flow of centrifugal pumps was calculated based on the Reynolds-averaged equations that resemble the shear stress transport (SST k-ω turbulence model. The results show that the blade passing frequency and shaft frequency are dominant in the spectrum of flow-induced noise, whereas the shaft component, amplitude value at shaft frequency, and peak frequencies around the shaft increase with decreasing flow. Through flow field analysis, the inlet backflow of the impeller occurs under 0.7 times the design flow. The pressure pulsation spectrum with backflow conditions validates the flow-induced noise findings. The velocity characteristics of the backflow zone at the inlet pipe were analyzed, and the dynamic characteristics of the backflow eddy during one impeller rotating period were simultaneously obtained by employing the backflow conditions. A flow visualization experiment was performed to confirm the numerical calculations.

  1. 21 CFR 864.9285 - Automated cell-washing centrifuge for immuno-hematology.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Automated cell-washing centrifuge for immuno... Establishments That Manufacture Blood and Blood Products § 864.9285 Automated cell-washing centrifuge for immuno-hematology. (a) Identification. An automated cell-washing centrifuge for immuno-hematology is a device used...

  2. Compound drum for a centrifugal separator

    International Nuclear Information System (INIS)

    1972-01-01

    This invention concerns a method for centrifugal separation of UF 6 . The invention provides a composite drum capable of rapid rotation for use in a centrifugal separating arrangement for gaseous materials. The drum is provided with a first drum section comprised of a metal and a second drum section comprised of a fiber-reinforced synthetic material. The second drum section is applied on the outside peripheral surface of the first drum section, where the second drum section is provided with a number of annular components, each of which is shorter than the first drum section

  3. Centrifuge impact cratering experiment 5

    Science.gov (United States)

    1984-01-01

    Transient crates motions, cratering flow fields, crates dynamics, determining impact conditions from total crater welt, centrifuge quarter-space cratering, and impact cratering mechanics research is documented.

  4. Comparison of the lysis centrifugation method with the conventional blood culture method in cases of sepsis in a tertiary care hospital.

    Science.gov (United States)

    Parikh, Harshal R; De, Anuradha S; Baveja, Sujata M

    2012-07-01

    Physicians and microbiologists have long recognized that the presence of living microorganisms in the blood of a patient carries with it considerable morbidity and mortality. Hence, blood cultures have become critically important and frequently performed test in clinical microbiology laboratories for diagnosis of sepsis. To compare the conventional blood culture method with the lysis centrifugation method in cases of sepsis. Two hundred nonduplicate blood cultures from cases of sepsis were analyzed using two blood culture methods concurrently for recovery of bacteria from patients diagnosed clinically with sepsis - the conventional blood culture method using trypticase soy broth and the lysis centrifugation method using saponin by centrifuging at 3000 g for 30 minutes. Overall bacteria recovered from 200 blood cultures were 17.5%. The conventional blood culture method had a higher yield of organisms, especially Gram positive cocci. The lysis centrifugation method was comparable with the former method with respect to Gram negative bacilli. The sensitivity of lysis centrifugation method in comparison to conventional blood culture method was 49.75% in this study, specificity was 98.21% and diagnostic accuracy was 89.5%. In almost every instance, the time required for detection of the growth was earlier by lysis centrifugation method, which was statistically significant. Contamination by lysis centrifugation was minimal, while that by conventional method was high. Time to growth by the lysis centrifugation method was highly significant (P value 0.000) as compared to time to growth by the conventional blood culture method. For the diagnosis of sepsis, combination of the lysis centrifugation method and the conventional blood culture method with trypticase soy broth or biphasic media is advocable, in order to achieve faster recovery and a better yield of microorganisms.

  5. Centrifugal pumps: fundamentals and classification

    International Nuclear Information System (INIS)

    Solar Manuel, A. M.

    2009-01-01

    Centrifugal pumps are usually employed to impulse water to elevate it, dose it or give it pressure or speed. They can be used with clean water or loaded with high solid concentration and don't work properly with air or another gas flow. There are another less used pumps, coming from volumetric or ram pumps to magnetic ones for specific uses. Centrifugal ones are rotokinetic pumps, like peripherical or lateral channel pumps. They work in a different way that non rotational kinetic ones and static ones. The work approaches their pre definition, selection, installation, operation and maintenance. It also review their morphology, hidromechanic principles and the basic elements pumps are made of. (Author)

  6. Automated cellular sample preparation using a Centrifuge-on-a-Chip.

    Science.gov (United States)

    Mach, Albert J; Kim, Jae Hyun; Arshi, Armin; Hur, Soojung Claire; Di Carlo, Dino

    2011-09-07

    The standard centrifuge is a laboratory instrument widely used by biologists and medical technicians for preparing cell samples. Efforts to automate the operations of concentration, cell separation, and solution exchange that a centrifuge performs in a simpler and smaller platform have had limited success. Here, we present a microfluidic chip that replicates the functions of a centrifuge without moving parts or external forces. The device operates using a purely fluid dynamic phenomenon in which cells selectively enter and are maintained in microscale vortices. Continuous and sequential operation allows enrichment of cancer cells from spiked blood samples at the mL min(-1) scale, followed by fluorescent labeling of intra- and extra-cellular antigens on the cells without the need for manual pipetting and washing steps. A versatile centrifuge-analogue may open opportunities in automated, low-cost and high-throughput sample preparation as an alternative to the standard benchtop centrifuge in standardized clinical diagnostics or resource poor settings.

  7. Multifunctional centrifugal grinding unit

    Science.gov (United States)

    Sevostyanov, V. S.; Uralskij, V. I.; Uralskij, A. V.; Sinitsa, E. V.

    2018-03-01

    The article presents scientific and engineering developments of multifunctional centrifugal grinding unit in which the selective effect of grinding bodies on the crushing material is realized, depending on its physical and mechanical characteristics and various schemes for organizing the technological process

  8. Conceptual design of a commercial supercritical CO2 gas turbine for the fast reactor power plant

    International Nuclear Information System (INIS)

    Muto, Y.; Ishizuka, T.; Aritomi, M.

    2010-01-01

    This paper describes the design results of turbine and compressors of a supercritical CO 2 gas turbine connected to the commercial sodium cooled fast reactor. Power output of the gas turbine-generator system is 750 MWe. The system consists of turbine, main compressor and bypass compressor. Turbine is axial flow type. Both axial flow and centrifugal compressors were designed. Aerodynamic, blade strength and rotor dynamics calculations were conducted. Achievable adiabatic efficiencies and cross-sectional structures are given. For this design conditions, the axial flow compressor is superior to the centrifugal compressor due to the large mass flow rate. (authors)

  9. Separation of Nanoparticles in Aqueous Multiphase Systems through Centrifugation

    KAUST Repository

    Akbulut, Ozge; Mace, Charles R.; Martinez, Ramses V.; Kumar, Ashok A.; Nie, Zhihong; Patton, Matthew R.; Whitesides, George M.

    2012-01-01

    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.

  10. 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.

  11. Centrifugal compressor design for electrically assisted boost

    International Nuclear Information System (INIS)

    Yang, M Y; Martinez-Botas, R F; Zhuge, W L; Qureshi, U; Richards, B

    2013-01-01

    Electrically assisted boost is a prominent method to solve the issues of transient lag in turbocharger and remains an optimized operation condition for a compressor due to decoupling from turbine. Usually a centrifugal compressor for gasoline engine boosting is operated at high rotational speed which is beyond the ability of an electric motor in market. In this paper a centrifugal compressor with rotational speed as 120k RPM and pressure ratio as 2.0 is specially developed for electrically assisted boost. A centrifugal compressor including the impeller, vaneless diffuser and the volute is designed by meanline method followed by 3D detailed design. Then CFD method is employed to predict as well as analyse the performance of the design compressor. The results show that the pressure ratio and efficiency at design point is 2.07 and 78% specifically

  12. Effects of centrifugation on gonadal and adrenocortical steroids in rats

    Science.gov (United States)

    Kakihana, R.; Butte, J. C.

    1980-01-01

    Many endocrine systems are sensitive to external changes in the environment. Both the pituitary adrenal and pituitary gonadal systems are affected by stress including centrifugation stress. The effect of centrifugation on the pituitary gonadal and pituitary adrenocortical systems was examined by measuring the gonadal and adrenal steroids in the plasma and brain following different duration and intensity of centrifugation stress in rats. Two studies were completed and the results are presented. The second study was carried out to describe the developmental changes of brain, plasma and testicular testosterone and dihydrotestosterone in Sprague Dawley rats so that the effect of centrifugation stress on the pituitary gonadal syatem could be better evaluated in future studies.

  13. Thermal hydrodynamic analysis of a countercurrent gas centrifuge

    International Nuclear Information System (INIS)

    Andrade, Delvonei Alves de

    1999-01-01

    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)

  14. 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.

  15. Thermally-controlled centrifuge for isotopic separation

    International Nuclear Information System (INIS)

    Cenedese, A.; Cunsolo, D.

    1976-01-01

    Among the various methods proposed to obtain lighter component enrichment in the isotopic separation of uranium, ultracentrifugation is becoming more and more interesting today, as this process becomes a useful alternate method to gaseous diffusion. The ultracentrifuge main gas-dynamic features are investigated in the present study. In particular, the field inside the centrifuge has been subdivided into three axial zones: an internal central zone, characterized by an essentially axial flow; two external zones, near the two caps of the centrifuge; two intermediate zones, of a length of the order of the radius. For the analytical solution the linearized Navier-Stokes equations have been considered. The central zone flow is solved by separating the independent variables; the corresponding eigenvalue problem has been solved numerically. A series of eigensolutions which satisfy boundary conditions at the walls of the cylinder has been calculated. An integral method for the superimposition of the above mentioned eigensolutions is proposed in order to satisfy the conditions at the tops for thermally-controlled centrifuges. (author)

  16. EM Task 9 - Centrifugal Membrane Filtration

    International Nuclear Information System (INIS)

    Stevens, B.G.; Stepan, D.J.; Hetland, M.D.

    1998-01-01

    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

  17. Multiple-isotope separation in gas centrifuge

    International Nuclear Information System (INIS)

    Wood, Houston G.; Mason, T.C.; Soubbaramayer

    1996-01-01

    In previous works, the Onsager's pancake equation was used to provide solution to the internal counter-current flow field, which is necessary to calculate solutions to the isotope transport equation. The diffusion coefficient was assumed to be constant which is a good approximation for gases with large molecular weights, and small differences in the molecular weights of the various isotopes. A new optimization strategy was presented for determining the operating parameters of a gas centrifuge to be used for multiple-component isotope separation. Scoop drag, linear wall temperature gradient, the feed rate ant the cut have been chosen as operating parameters for the optimization. The investigation was restricted to a single centrifuge, and the problem of cascading for multiple-isotope separation was not addressed. The model describing the flow and separation phenomena in centrifuge includes a set of equations describing the fluid dynamics of the counter-current flow and the diffusion equations written for each isotope of the mixture. In this paper, an optimization algorithm is described and applied to an example for the re enrichment of spent reactor uranium

  18. Influence of the centrifuge time of primary plasma tubes on routine coagulation testing.

    Science.gov (United States)

    Lippi, Giuseppe; Salvagno, Gian Luca; Montagnana, Martina; Manzato, Franco; Guidi, Gian Cesare

    2007-07-01

    Preparation of blood specimens is a major bottleneck in the laboratory throughput. Reliable strategies for reducing the time required for specimen processing without affecting quality should be acknowledged, especially for laboratories performing stat analyses. The present investigation was planned to establish a minimal suitable centrifuge time for primary samples collected for routine coagulation testing. Five sequential primary vacuum tubes containing 0.109 mol/l buffered trisodium citrate were collected from 10 volunteers and were immediately centrifuged on a conventional centrifuge at 1500 x g, at room temperature for 1, 2, 5, 10 and 15 min, respectively. Hematological and routine coagulation testing, including prothrombin time, activated partial thromboplastin time and fibrinogen, were performed. The centrifugation time was inversely associated with residual blood cell elements in plasma, especially platelets. Statistically significant variations from the reference 15-min centrifuge specimens were observed for fibrinogen in samples centrifuged for 5 min at most and for the activated partial thromboplastin time in samples centrifuged for 2 min at most. Meaningful biases related to the desirable bias were observed for fibrinogen in samples centrifuged for 2 min at most, and for the activated partial thromboplastin time in samples centrifuged for 1 min at most. According to our experimental conditions, a 5-10 min centrifuge time at 1500 x g may be suitable for primary tubes collected for routine coagulation testing.

  19. Design of small centrifugal compressor test model for a supercritical CO2 compressor in the fast reactor power plant

    International Nuclear Information System (INIS)

    Muto, Y.; Ishizuka, T.; Aritomi, M.

    2008-01-01

    In order to clarify the CO 2 compressor performance in the vicinity of critical point, a research project has been started in Tokyo Institute of Technology based on Japanese government fund. This paper describes how fundamental parameters were selected and sizing of a small and high speed impeller of the test centrifugal compressor. The concept of canned type compressor structures provided with high speed electric motor and preliminary aerodynamic performance prediction are also given. (authors)

  20. Scaling of rotation and isotope separation in a vacuum-arc centrifuge

    International Nuclear Information System (INIS)

    Prasad, R.R.; Krishnan, M.

    1987-01-01

    Scaling is described of rotation, plasma column size and separation in a vacuum-arc centrifuge. The vacuum-arc centrifuge is a magnetized, fulled ionized, quasineutral column of plasma. The source of plasma is a vacuum-arc discharge between a negatively biased cathode and a grounded mesh anode. Rigid-body rotation, induced by the J x B force, causes radial, centrifugal separation of isotopes in the plasma column. Salient features of a fluid model that provides an understanding of rotation and the concomitant isotope separation in the vacuum-arc centrifuge are described. Scaling of rotation and plasma column size is found be consistent with the model. Measurements of isotope separation, also found to agree with the predictions of the model, are presented. Results of a parametric analysis of isotope separation in such a vacuum-arc centrifuge, using the fluid model and the observed scaling laws, are described. An analysis of the energy cost of separation of the vacuum-arc centrifuge shows that it typically requires only 70 keV/separated atom. (orig.)

  1. A 'smart' tube holder enables real-time sample monitoring in a standard lab centrifuge.

    Science.gov (United States)

    Hoang, Tony; Moskwa, Nicholas; Halvorsen, Ken

    2018-01-01

    The centrifuge is among the oldest and most widely used pieces of laboratory equipment, with significant applications that include clinical diagnostics and biomedical research. A major limitation of laboratory centrifuges is their "black box" nature, limiting sample observation to before and after centrifugation. Thus, optimized protocols require significant trial and error, while unoptimized protocols waste time by centrifuging longer than necessary or material due to incomplete sedimentation. Here, we developed an instrumented centrifuge tube receptacle compatible with several commercial benchtop centrifuges that can provide real-time sample analysis during centrifugation. We demonstrated the system by monitoring cell separations during centrifugation for different spin speeds, concentrations, buffers, cell types, and temperatures. We show that the collected data are valuable for analytical purposes (e.g. quality control), or as feedback to the user or the instrument. For the latter, we verified an adaptation where complete sedimentation turned off the centrifuge and notified the user by a text message. Our system adds new functionality to existing laboratory centrifuges, saving users time and providing useful feedback. This add-on potentially enables new analytical applications for an instrument that has remained largely unchanged for decades.

  2. Horizontal vibrations of piles in a centrifuge

    International Nuclear Information System (INIS)

    Bourdin, B.

    1987-01-01

    The aim of the thesis is the study of soil dynamics for important structures like nuclear power plants, offshore platforms, dams etc. Experimental results of horizontal vibrations on a pile partially anchored in a soil scale model put into a centrifuge are presented. Mechanical similitude conditions from equilibrium equations or rheologic laws are described. After a description of testing equipment (centrifuge, electrodynamic excitator) experimental results are interpreted with a model. Non-linearities on frequency response curves are characterized [fr

  3. The commercial role for centrifuge enrichment

    International Nuclear Information System (INIS)

    Readle, P.H.; Wilcox, P.

    1987-01-01

    The enrichment market is extremely competitive and capacity greatly exceeds demand. BNFL [British Nuclear Fuels Ltd.] is in a unique position in having commercial experience of the two enrichment technologies currently used industrially: diffusion, and centrifuge enrichment through its associate company Urenco. In addition, BNFL is developing laser enrichment techniques as part of a UK development programme. The paper describes the enrichment market, briefly discusses the relative merits of the various methods of uranium enrichment and concludes that the gas centrifuge will be best able to respond to market needs for at least the remainder of the century. (author)

  4. The standard centrifuge method accurately measures vulnerability curves of long-vesselled olive stems.

    Science.gov (United States)

    Hacke, Uwe G; Venturas, Martin D; MacKinnon, Evan D; Jacobsen, Anna L; Sperry, John S; Pratt, R Brandon

    2015-01-01

    The standard centrifuge method has been frequently used to measure vulnerability to xylem cavitation. This method has recently been questioned. It was hypothesized that open vessels lead to exponential vulnerability curves, which were thought to be indicative of measurement artifact. We tested this hypothesis in stems of olive (Olea europea) because its long vessels were recently claimed to produce a centrifuge artifact. We evaluated three predictions that followed from the open vessel artifact hypothesis: shorter stems, with more open vessels, would be more vulnerable than longer stems; standard centrifuge-based curves would be more vulnerable than dehydration-based curves; and open vessels would cause an exponential shape of centrifuge-based curves. Experimental evidence did not support these predictions. Centrifuge curves did not vary when the proportion of open vessels was altered. Centrifuge and dehydration curves were similar. At highly negative xylem pressure, centrifuge-based curves slightly overestimated vulnerability compared to the dehydration curve. This divergence was eliminated by centrifuging each stem only once. The standard centrifuge method produced accurate curves of samples containing open vessels, supporting the validity of this technique and confirming its utility in understanding plant hydraulics. Seven recommendations for avoiding artefacts and standardizing vulnerability curve methodology are provided. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  5. Effect of centrifugation on dynamic susceptibility of magnetic fluids

    International Nuclear Information System (INIS)

    Pshenichnikov, Alexander; Lebedev, Alexander; Lakhtina, Ekaterina; Kuznetsov, Andrey

    2017-01-01

    Highlights: • Six samples of magnetic fluid were obtained by centrifuging two base ferrocolloids. • Aggregates in magnetic fluids are main reason of dynamic susceptibility dispersion. • Centrifugation is an effective way of changing the dynamic susceptibility. - Abstract: The dispersive composition, dynamic susceptibility and spectrum of times of magnetization relaxation for six samples of magnetic fluid obtained by centrifuging two base colloidal solutions of the magnetite in kerosene was investigated experimentally. The base solutions differed by the concentration of the magnetic phase and the width of the particle size distribution. The procedure of cluster analysis allowing one to estimate the characteristic sizes of aggregates with uncompensated magnetic moments was described. The results of the magnetogranulometric and cluster analyses were discussed. It was shown that centrifugation has a strong effect on the physical properties of the separated fractions, which is related to the spatial redistribution of particles and multi-particle aggregates. The presence of aggregates in magnetic fluids is interpreted as the main reason of low-frequency (0.1–10 kHz) dispersion of the dynamic susceptibility. The obtained results count in favor of using centrifugation as an effective means of changing the dynamic susceptibility over wide limits and obtaining fluids with the specified type of susceptibility dispersion.

  6. Effect of centrifugation on dynamic susceptibility of magnetic fluids

    Energy Technology Data Exchange (ETDEWEB)

    Pshenichnikov, Alexander, E-mail: pshenichnikov@icmm.ru; Lebedev, Alexander; Lakhtina, Ekaterina; Kuznetsov, Andrey

    2017-06-15

    Highlights: • Six samples of magnetic fluid were obtained by centrifuging two base ferrocolloids. • Aggregates in magnetic fluids are main reason of dynamic susceptibility dispersion. • Centrifugation is an effective way of changing the dynamic susceptibility. - Abstract: The dispersive composition, dynamic susceptibility and spectrum of times of magnetization relaxation for six samples of magnetic fluid obtained by centrifuging two base colloidal solutions of the magnetite in kerosene was investigated experimentally. The base solutions differed by the concentration of the magnetic phase and the width of the particle size distribution. The procedure of cluster analysis allowing one to estimate the characteristic sizes of aggregates with uncompensated magnetic moments was described. The results of the magnetogranulometric and cluster analyses were discussed. It was shown that centrifugation has a strong effect on the physical properties of the separated fractions, which is related to the spatial redistribution of particles and multi-particle aggregates. The presence of aggregates in magnetic fluids is interpreted as the main reason of low-frequency (0.1–10 kHz) dispersion of the dynamic susceptibility. The obtained results count in favor of using centrifugation as an effective means of changing the dynamic susceptibility over wide limits and obtaining fluids with the specified type of susceptibility dispersion.

  7. A comparison of two centrifuge techniques for constructing vulnerability curves: insight into the 'open-vessel' artifact.

    Science.gov (United States)

    Yin, Pengxian; Meng, Feng; Liu, Qing; An, Rui; Cai, Jing; Du, Guangyuan

    2018-03-30

    A vulnerability curve (VC) describes the extent of xylem cavitation resistance. Centrifuges have been used to generate VCs for decades via static- and flow-centrifuge methods. Recently, the validity of the centrifuge techniques has been questioned. Researchers have hypothesized that the centrifuge techniques might yield unreliable VCs due to the open-vessel artifact. However, other researchers reject this hypothesis. The focus of the dispute is centred on whether exponential VCs are more reliable when the static-centrifuge method is used than with the flow-centrifuge method. To further test the reliability of the centrifuge technique, two centrifuges were manufactured to simulate the static- and flow-centrifuge methods. VCs of three species with open vessels of known lengths were constructed using the two centrifuges. The results showed that both centrifuge techniques produced invalid VCs for Robinia because the water flow through stems under mild tension in centrifuges led to an increasing loss of water conductivity. Additionally, the injection of water in the flow-centrifuge exacerbated the loss of water conductivity. However, both centrifuge techniques yielded reliable VCs for Prunus, regardless of the presence of open vessels in the tested samples. We conclude that centrifuge techniques can be used in species with open vessels only when the centrifuge produces a VC that matches the bench-dehydration VC. This article is protected by copyright. All rights reserved.

  8. Development of a shielded ion microprobe analyzer (SIMA) and its application to fast reactor fuel elements

    International Nuclear Information System (INIS)

    Yuji, E.; Junji, K.; Sadamu, Y.; Toshiyuki, I.

    1983-01-01

    A shielded ion microprobe analyzer for elemental and isotopic analyses of irradiated fast reactor fuel and fuel component has been developed and installed in an alpha-gamma hot cell. Radiation shielding of the equipment ensures the radiation dose of -7 C/kg) for 5 Ci (1.85 x 10 11 Bq) of a 60 Co source. Hot samples can be automatically transferred from the cell to the sample chamber of the analyzer. Contamination inside the equipment through sputtering of the radioactive materials can be reduced with a special device. Distribution and migration of fission products, such as 137 Cs, 138 Ba, and 90 Sr, and of fissile materials, such as 235 U and 239 Pu in irradiated mixed-oxide fuel, and isotopic ratios of the elements can be obtained very precisely and quickly

  9. Development of a shielded ion microprobe analyzer (SIMA) and its application to fast reactor fuel elements

    International Nuclear Information System (INIS)

    Enokido, Y.; Itaki, T.; Komatsu, J.; Yamanouchi, S.

    1983-01-01

    A shielded ion microprobe analyzer for elemental and isotopic analyses of irradiated fast reactor fuel and fuel component has been developed and installed in an alpha-gamma hot cell. Radiation shielding of the equipment ensures the radiation dose of -7 C/kg) for 5 Ci (1.85 X 10 11 Bq) of a 60 Co source. Hot samples can be automatically transferred from the cell to the sample chamber of the analyzer. Contamination inside the equipment through sputtering of the radioactive materials can be reduced with a special device. Distribution and migration of fission products, such as 137 Cs, 138 Ba, and 90 Sr, and of fissile materials, such as 235 U and 239 Pu in irradiated mixed-oxide fuel, and isotopic ratios of the elements can be obtained very precisely and quickly

  10. Centar's gas centrifuge enrichment project

    International Nuclear Information System (INIS)

    Abajian, V.V.; Fishman, A.M.

    1976-01-01

    Plans for the building and operating of Centar Associates gas centrifuge uranium enrichment plant are described. Operating costs and machine manufacture are considered. Commitments with the utilities are summarised. (U.K.)

  11. Microcomputer-based instrument for the detection and analysis of precession motion in a gas centrifuge machine. Revision 1

    International Nuclear Information System (INIS)

    Paulus, S.S.

    1986-03-01

    The Centrifuge Procession Analyzer (CPA) is a microcomputer-based instrument which detects precession motion in a gas centrifuge machine and calculates the amplitude and frequency of precession. The CPA consists of a printed circuit board which contains signal-conditioning circuitry and a 24-bit counter and an INTEL iSBC 80/24 single/board computer. Pression motion is detected by monitoring a signal generated by a variable reluctance pick-up coil in the top of the centrifuge machine. This signal is called a Fidler signal. The initial Fidler signal triggers a counter which is clocked by a high-precision, 20.000000-MHz, temperature-controlled, crystal oscillator. The contents of the counter are read by the computer and the counter reset after every ten Fidler signals. The speed of the centrifuge machine and the amplitude and frequency of precession are calculated and the results are displayed on a liquid crystal display on the front panel of the CPA. The report contains results from data generated by a Fidler signal simulator and data taken when the centrifuge was operated under three test conditions: (1) nitrogen gas during drive-up, steady state, and drive-down; (2) xenon gas during slip test, steady state, and the addition of gas; and (3) no gas during steady state. The qualitative results were consistent with experience with centrifuge machines using UF 6 in that the amplitude of precession increased and the frequency of precession decreased during drive-up, drive-down and the slip check. The magnitude of the amplitude and frequency of precession were proportional to the molecular weight of the gases in steady state

  12. Effect of sludge behavior on performance of centrifugal contactor

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, A.; Sano, Y.; Takeuchi, M. [Japan Atomic Energy Agency - JAEA, 4-33 Muramatsu Tokai-mura Naka-gun Ibaraki-pref. 319-1194 (Japan)

    2016-07-01

    The Japan Atomic Energy Agency has been developing an annular centrifugal contactor for solvent extraction in spent fuel reprocessing, which allows the mixing of aqueous and organic phases in the annular area and their separation from the mixed phase in the rotor. The effects of sludge behavior on the performance of a centrifugal contactor were investigated. Sludge accumulation during the operation of the centrifugal contactor was observed only in the rotor. Based on the sludge accumulation behavior, the effects of rotor sludge accumulation on the performance of phase separation and extraction were investigated using several types of rotors, which simulated different sludge accumulation levels in the separation area. It was confirmed that rotor sludge accumulation would affect the phase separation performance but not the extraction performance. This can be explained by the structure of the centrifugal contactor, wherein the extraction reaction and phase separation mainly proceed in the housing and rotor, respectively.

  13. Return to Flying Duties Following Centrifuge or Vibration Exposures

    Science.gov (United States)

    Scheuring, Richard A.; Clarke, Jonathan; Jones, Jeffrey A.

    2009-01-01

    Introduction: In an effort to determine the human performance limits for vibration in spacecraft being developed by NASA, astronauts were evaluated during a simulated launch profile in a centrifuge/vibration environment and separate vibration-only simulation. Current USAF and Army standards for return to flight following centrifuge exposures require 12-24 hours to pass before a crewmember may return to flying duties. There are no standards on vibration exposures and return to flying duties. Based on direct observation and provocative neurological testing of the astronauts, a new standard for return to flying duties following centrifuge and/or vibration exposures was established. Methods: 13 astronaut participants were exposed to simulated launch profiles in a + 3.5 Gx bias centrifuge/vibration environment and separately on a vibration table at the NASA-Ames Research Center. Each subject had complete neurological evaluations pre- and post-exposure for the centrifuge/vibration runs with the NASA neurological function rating scale (NFRS). Subjects who participated in the vibration-only exposures had video oculography performed with provocative maneuvers in addition to the NFRS. NFRS evaluations occurred immediately following each exposure and at 1 hour post-run. Astronauts who remained symptomatic at 1 hour had repeat NFRS performed at 1 hour intervals until the crewmember was asymptomatic. Results: Astronauts in the centrifuge/vibration study averaged a 3-5 point increase in NFRS scores immediately following exposure but returned to baseline 3 hours post-run. Subjects exposed to the vibration-only simulation had a 1-3 point increase following exposure and returned to baseline within 1-2 hours. Pre- and post- vibration exposure video oculography did not reveal any persistent ocular findings with provocative testing 1 hour post-exposure. Discussion: Based on direct observations and objective measurement of neurological function in astronauts following simulated launch

  14. Method and refrigerants for replacing existing refrigerants in centrifugal compressors

    International Nuclear Information System (INIS)

    Kopko, W.L.

    1991-01-01

    This patent describes a method for replacing an existing refrigerant in a centrifugal compressor. It comprises selecting a desired impeller Mach number for the centrifugal compressor; selecting a base refrigerant constituent; combining at least one additive refrigerant constituent with the base refrigerant constituent to form a replacement refrigerant having at least one physical or chemical property different from the existing refrigerant and substantially providing the desired impeller Mach number in the centrifugal compressor; and replacing the existing refrigerant with the replacement refrigerant

  15. Robust alignment of chromatograms by statistically analyzing the shifts matrix generated by moving window fast Fourier transform cross-correlation.

    Science.gov (United States)

    Zhang, Mingjing; Wen, Ming; Zhang, Zhi-Min; Lu, Hongmei; Liang, Yizeng; Zhan, Dejian

    2015-03-01

    Retention time shift is one of the most challenging problems during the preprocessing of massive chromatographic datasets. Here, an improved version of the moving window fast Fourier transform cross-correlation algorithm is presented to perform nonlinear and robust alignment of chromatograms by analyzing the shifts matrix generated by moving window procedure. The shifts matrix in retention time can be estimated by fast Fourier transform cross-correlation with a moving window procedure. The refined shift of each scan point can be obtained by calculating the mode of corresponding column of the shifts matrix. This version is simple, but more effective and robust than the previously published moving window fast Fourier transform cross-correlation method. It can handle nonlinear retention time shift robustly if proper window size has been selected. The window size is the only one parameter needed to adjust and optimize. The properties of the proposed method are investigated by comparison with the previous moving window fast Fourier transform cross-correlation and recursive alignment by fast Fourier transform using chromatographic datasets. The pattern recognition results of a gas chromatography mass spectrometry dataset of metabolic syndrome can be improved significantly after preprocessing by this method. Furthermore, the proposed method is available as an open source package at https://github.com/zmzhang/MWFFT2. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Medical incidences during centrifuge training and F-16 flying in the Netherlands

    NARCIS (Netherlands)

    Holewijn, M.

    1996-01-01

    A survey in the NAMC database containing the records of centrifuge runs of candidate and experienced pilots revealed that in 15.1% of the centrifuge training sessions, a run was stopped. The major reasons were motion sickness (31%), fatigue (28%), and arrhythmias (22%). During centrifuge training at

  17. Spectroscopy of molecules in very high rotational states using an optical centrifuge.

    Science.gov (United States)

    Yuan, Liwei; Toro, Carlos; Bell, Mack; Mullin, Amy S

    2011-01-01

    We have developed a high power optical centrifuge for measuring the spectroscopy of molecules in extreme rotational states. The optical centrifuge has a pulse energy that is more than 2 orders of magnitude greater than in earlier instruments. The large pulse energy allows us to drive substantial number densities of molecules to extreme rotational states in order to measure new spectroscopic transitions that are not accessible with traditional methods. Here we demonstrate the use of the optical centrifuge for measuring IR transitions of N2O from states that have been inaccessible until now. In these studies, the optical centrifuge drives N2O molecules into states with J ~ 200 and we use high resolution transient IR probing to measure the appearance of population in states with J = 93-99 that result from collisional cooling of the centrifuged molecules. High resolution Doppler broadened line profile measurements yield information about the rotational and translational energy distributions in the optical centrifuge.

  18. Centrifuge - dewatering of oil sand fluid tailings: phase 2 field-scale test

    Energy Technology Data Exchange (ETDEWEB)

    Seto, Jack T.C. [BGC Engineering Inc (Canada); O' Kane, Mike [O' Kane Consultants Inc (Canada); Donahue, Robert [Applied Geochemical Solutions Engineering (Canada); Lahaie, Rick [Syncrude Canada Ltd (Canada)

    2011-07-01

    In order to reduce the accumulation of oil sand fluid fine tailings (FFT) and to create trafficable surfaces for reclamation, Syncrude Canada Ltd. has been studying several tailings technologies. Centrifuge-dewatering is one such technology. This paper discusses the phase 2 field-scale tests for centrifuge-dewatering of oil sand FFT. In centrifuge-dewatering, FFT is diluted and treated with flocculant, then processed through a centrifuge plant and the high-density underflow is transported to a tailings deposit. This technology has evolved since 2005 from laboratory bench scale tests. More than 10,000 cubic meters of centrifuge cake was treated, produced and transported to ten different deposits over a 12-week period from August to October 2010. The amount of solids in FFT was increased from 30% to 50% by centrifuging. Sampled deposits were tested and instrumented for in situ strength. It can be concluded that the deposits can be strengthened and densified by natural dewatering processes like freeze-thaw action and evaporative drying.

  19. Onsager's pancake approximation for the fluid dynamics of a gas centrifuge

    International Nuclear Information System (INIS)

    Wood, H.G. III; Morton, J.B.

    1980-01-01

    A previously unpublished theory for describing the internal flow in a gas centrifuge is presented. The theory is based on boundary layer type arguments on the side walls of the centrifuge with the additional approximation of neglecting radial diffusion of radial momentum. The effects of the top and bottom end caps are incorporated through Ekman layer solutions. The results are presented in a form amenable to numerical calculations. Some sample calculations are presented for the special case of a centrifuge with a linear temperature profile on the wall and the top and bottom of the centrifuge at the same temperature as the corresponding end of the side wall

  20. Onsager's pancake approximation for the fluid dynamics of a gas centrifuge

    International Nuclear Information System (INIS)

    Wood, H.G.

    1980-01-01

    A previously unpublished theory for describing the internal flow in a gas centrifuge is presented. The theory is based on boundary-layer-type arguments on the side walls of the centrifuge with the additional approximation of neglecting radial diffusion of radial momentum. The effects of the top and bottom end caps are incorporated through Ekman-layer solutions. The results are presented in a form amenable to numerical calculations. Some sample calculations are presented for the special case of a centrifuge with a linear temperature profile on the wall and the top and bottom of the centrifuge at the same temperature as the corresponding end of the side wall. (author)

  1. Preflight screening techniques for centrifuge-simulated suborbital spaceflight.

    Science.gov (United States)

    Pattarini, James M; Blue, Rebecca S; Castleberry, Tarah L; Vanderploeg, James M

    2014-12-01

    Historically, space has been the venue of the healthy individual. With the advent of commercial spaceflight, we face the novel prospect of routinely exposing spaceflight participants (SPFs) with multiple comorbidities to the space environment. Preflight screening procedures must be developed to identify those individuals at increased risk during flight. We examined the responses of volunteers to centrifuge accelerations mimicking commercial suborbital spaceflight profiles to evaluate how potential SFPs might tolerate such forces. We evaluated our screening process for medical approval of subjects for centrifuge participation for applicability to commercial spaceflight operations. All registered subjects completed a medical questionnaire, physical examination, and electrocardiogram. Subjects with identified concerns including cardiopulmonary disease, hypertension, and diabetes were required to provide documentation of their conditions. There were 335 subjects who registered for the study, 124 who completed all prescreening, and 86 subjects who participated in centrifuge trials. Due to prior medical history, five subjects were disqualified, most commonly for psychiatric reasons or uncontrolled medical conditions. Of the subjects approved, four individuals experienced abnormal physiological responses to centrifuge profiles, including one back strain and three with anxiety reactions. The screening methods used were judged to be sufficient to identify individuals physically capable of tolerating simulated suborbital flight. Improved methods will be needed to identify susceptibility to anxiety reactions. While severe or uncontrolled disease was excluded, many subjects successfully participated in centrifuge trials despite medical histories of disease that are disqualifying under historical spaceflight screening regimes. Such screening techniques are applicable for use in future commercial spaceflight operations.

  2. An experiment to test centrifugal confinement for fusion

    International Nuclear Information System (INIS)

    Ellis, R.F.; Hassam, A.B.; Messer, S.; Osborn, B.R.

    2001-01-01

    The basic idea of centrifugal confinement is to use centrifugal forces from supersonic rotation to augment conventional magnetic confinement. Optimizing this 'knob' results in a fusion device that features four advantages: steady state, no disruptions, superior cross-field confinement, and a simpler coil configuration. The idea rests on two prongs: first, centrifugal forces can confine plasmas to desired regions of shaped magnetic fields; second, the accompanying large velocity shear can stabilize even magnetohydrodynamic (MHD) instabilities. A third feature is that the velocity shear also viscously heats the plasma; no auxiliary heating is necessary to reach fusion temperatures. Regarding transport, the velocity shear can also quell microturbulence, leading to fully classical confinement, as there are no neoclassical effects. Classical parallel electron transport then sets the confinement time. These losses are minimized by a large Pastukhov factor resulting from the deep centrifugal potential well: at Mach 4-5, the Lawson criterion is accessible. One key issue is whether velocity shear will be sufficient by itself to stabilize MHD interchanges. Numerical simulations indicate that laminar equilibria can be obtained at Mach numbers of 4-5 but that the progression toward laminarity with increasing Mach number is accompanied by residual convection from the interchanges. The central goal of the Maryland Centrifugal Torus (MCT) [R. F. Ellis et al., Bull. Am. Phys. Soc. 44, 48 (1998)] is to obtain MHD stability from velocity shear. As an assist to accessing laminarity, MCT will incorporate two unique features: plasma elongation and toroidal magnetic field. The former raises velocity shear efficiency, and modest magnetic shear should suppress residual convection

  3. Solvent extraction studies in miniature centrifugal contactors

    International Nuclear Information System (INIS)

    Siczek, A.A.; Meisenhelder, J.H.; Bernstein, G.J.; Steindler, M.J.

    1980-01-01

    A miniature short-residence-time centrifugal solvent extraction contactor and an eight-stage laboratory minibank of centrifugal contactors were used for testing the possibility of utilizing kinetic effects for improving the separation of uranium from ruthenium and zirconium in the Purex process. Results of these tests showed that a small improvement found in ruthenium and zirconium decontamination in single-stage solvent extraction tests was lost in the multistage extraction tests- in fact, the extent of saturation of the solvent by uranium, rather than the stage residence time, controlled the extent of ruthenium and zirconium extraction. In applying the centrifugal contactor to the Purex process, the primary advantages would be less radiolytic damage to the solvent, high troughput, reduced solvent inventory, and rapid attainment of steady-state operating conditions. The multistage mini contactor was also tested to determine the suitability of short-residence-time contactors for use with the Civex and Thorex processes and was found to be compatible with the requirements of these processes. (orig.) [de

  4. Comparison between analyzed and calculated nutrient content of fast foods using two consecutive versions of the Danish food composition databank: FOODCOMP and FRIDA

    DEFF Research Database (Denmark)

    Biltoft-Jensen, Anja Pia; Knuthsen, Pia; Saxholt, Erling

    2017-01-01

    -to-eat fast foods were collected from fast food outlets, separated into their components and weighed. Typical components were bread, French fries, vegetables, meat and dressings. The fast foods were analyzed, and energy, protein, saturated fat, iron, thiamin, potassium and sodium contents were compared......The objective of this study was to compare the content of selected nutrients of fast foods determined by chemical analysis versus estimated by recipe calculation based on data from two versions of the Danish food composition databank, FOODCOMP and the latest FRIDA. A total of 155 samples of ready....... For the individual fast foods, the error percentages were both acceptable (50%). Future challenges for the databank in relation to recipe calculation are to include more varieties, a better coverage of foods used as ingredients, and inclusion of analytical values of mixed dishes...

  5. Influence of centrifuge brake on residual platelet count and routine coagulation tests in citrated plasma.

    Science.gov (United States)

    Daves, Massimo; Giacomuzzi, Katia; Tagnin, Enrico; Jani, Erika; Adcock Funk, Dorothy M; Favaloro, Emmanuel J; Lippi, Giuseppe

    2014-04-01

    Sample centrifugation is an essential step in the coagulation laboratory, as clotting tests are typically performed on citrated platelet (PLT) poor plasma (PPP). Nevertheless, no clear indication has been provided as to whether centrifugation of specimens should be performed with the centrifuge brake set to on or off. Fifty consecutive sodium citrate anticoagulated samples were collected and divided into two aliquots. The former was centrifuged as for Clinical Laboratory Standards Institute (CLSI) guidelines with the centrifuge brake set to on, whereas the latter was centrifuged again as for CLSI guidelines, but with the brake set to off. In the PPP of all samples, a PLT count was performed, followed by the analysis of activated partial thromboplastin time (APTT), prothrombin time (PT) and fibrinogen (FBG). The PLT count after samples centrifugation was substantially reduced, either with centrifuge brake set to on or off (5 ± 1 versus 3 ± 1 × 10/l; P = 0.009). The frequency of samples exceeding a PLT count less than 10 × 10/l was nearly double in samples centrifuged with the brake on than in those with the brake off (14 versus 8%; P centrifuge brake set to on (mean bias 0.2 s; P centrifuge brake set to on (mean bias 0.29 g/l; P centrifugation for routine coagulation testing should be preferably performed with the centrifuge brake set to off for providing a better quality specimen.

  6. [Hemolysis Performance Analysis of the Centrifugal Maglev Blood Pump].

    Science.gov (United States)

    Wang, Yiwen; Zhang, Fan; Fang, Yuan; Dong, Baichuan; Zhou, Liang

    2016-05-01

    In order to analyze and study the hemolysis performance of the centrifugal maglev blood pump, which was designed by ourselves, this paper built the mathematical model and computational fluid dynamics analyzed it using Fluent. Then we set up the in vitro hemolysis experiment platform, in case of the design condition, the content of free hemoglobin and hematocrit in plasma were measured in a certain time interval, and calculated the normalized index of hemolysis of the blood pump. The numerical simulation results show the internal static pressure distribution is smooth inside the pump, the wal shear stress inside the pump is less than 150 Pa. Therefore, the red blood cel damage and exposure time is independent. The normalized index of hemolysis is (0.002 9±0.000 7) mg/L, which is in accordance with human physiological requirement.

  7. Lightweight Shield for Centrifuge

    Science.gov (United States)

    Luper, C.

    1982-01-01

    Centrifuge bowl composed of laminated aluminum offers required combination of high strength at reduced weight. Around outside wall of bowl core of 1/16 inch thick spun aluminum are wrapped two layers of aluminum, each also one-sixteenth inch thick. Layered structure prevents cracks from propagating through wall.

  8. Identify the Rotating Stall in Centrifugal Compressors by Fractal Dimension in Reconstructed Phase Space

    Directory of Open Access Journals (Sweden)

    Le Wang

    2015-11-01

    Full Text Available Based on phase space reconstruction and fractal dynamics in nonlinear dynamics, a method is proposed to extract and analyze the dynamics of the rotating stall in the impeller of centrifugal compressor, and some numerical examples are given to verify the results as well. First, the rotating stall of an existing low speed centrifugal compressor (LSCC is numerically simulated, and the time series of pressure in the rotating stall is obtained at various locations near the impeller outlet. Then, the phase space reconstruction is applied to these pressure time series, and a low-dimensional dynamical system, which the dynamics properties are included in, is reconstructed. In phase space reconstruction, C–C method is used to obtain the key parameters, such as time delay and the embedding dimension of the reconstructed phase space. Further, the fractal characteristics of the rotating stall are analyzed in detail, and the fractal dimensions are given for some examples to measure the complexity of the flow in the post-rotating stall. The results show that the fractal structures could reveal the intrinsic dynamics of the rotating stall flow and could be considered as a characteristic to identify the rotating stall.

  9. Numerical optimization for separation power of gas centrifuge

    International Nuclear Information System (INIS)

    Jiang Dongjun; Zeng Shi; Liu Bing

    2012-01-01

    In order to obtain higher separation power of the gas centrifuge, the code was developed to solve the flow-field of the counter-current to acquire the separation power, which was integrated with the iSight software, so a numerical optimization model for separation power was presented, in which the driver conditions and the geometry parameters of the waste baffle were optimized to get the maximum separation power using the sequential quadratic programming arithmetic, and the 12% higher results was acquired, which shows the feasibility of this method. The results also note that the separation power of gas centrifuge is sensitive to the driver conditions and the structure parameters of the waste baffle, so it is necessary to perform the optimization calculation for the certain gas centrifuge model. (authors)

  10. Wave-Driven Rotation In Centrifugal Mirrors

    International Nuclear Information System (INIS)

    Fetterman, Abraham J.; Fisch, Nathaniel J.

    2011-01-01

    Centrifugal mirrors use supersonic rotation to provide axial confinement and enhanced stability. Usually the rotation is produced using electrodes, but these electrodes have limited the rotation to the Alfven critical ionization velocity, which is too slow to be useful for fusion. Instead, the rotation could be produced using radio frequency waves. A fixed azimuthal ripple is a simple and efficient wave that could produce rotation by harnessing alpha particle energy. This is an extension of the alpha channeling effect. The alpha particle power and efficiency in a simulated devices is sufficient to produce rotation without external energy input. By eliminating the need for electrodes, this opens new opportunities for centrifugal traps.

  11. Development of a new measurement method for fast breeder reactor fuel burnup using a shielded ion microprobe analyzer

    International Nuclear Information System (INIS)

    Mizuno, M.; Enokido, Y.; Itaki, T.; Kono, K.; Unno, I.; Yamanouchi, S.

    1985-01-01

    A new method of burnup measurement using a shielded ion microprobe analyzer (SIMA) has been developed. The method is based on the isotope analysis of uranium, plutonium, and fission products in irradiated mixed oxide fuel by means of secondary ion mass spectrometry (SIMS). Fourteen samples irradiated in the Japanese experimental fast reactor JOYO were examined. The maximum local burnup of JOYO MK-I core fuels was about5.1 at. %. The axial burnup distribution of the fuel pin was in good agreement with that of the sibling pin in the same subassembly, measured by surface ionization mass spectrometry, which requires the chemical separation of fission products and heavy metals. The new method facilitates the rapid and accurate measurement of fast breeder reactor fuel burnup without human radiation exposure during sample preparation and analysis

  12. Reduction of relative centrifugation force within injectable platelet-rich-fibrin (PRF) concentrates advances patients' own inflammatory cells, platelets and growth factors: the first introduction to the low speed centrifugation concept.

    Science.gov (United States)

    Choukroun, J; Ghanaati, S

    2018-02-01

    The aim of this study was to analyze systematically the influence of the relative centrifugation force (RCF) on leukocytes, platelets and growth factor release within fluid platelet-rich fibrin matrices (PRF). Systematically using peripheral blood from six healthy volunteers, the RCF was reduced four times for each of the three experimental protocols (I-III) within the spectrum (710-44 g), while maintaining a constant centrifugation time. Flow cytometry was applied to determine the platelets and leukocyte number. The growth factor concentration was quantified 1 and 24 h after clotting using ELISA. Reducing RCF in accordance with protocol-II (177 g) led to a significantly higher platelets and leukocytes numbers compared to protocol-I (710 g). Protocol-III (44 g) showed a highly significant increase of leukocytes and platelets number in comparison to -I and -II. The growth factors' concentration of VEGF and TGF-β1 was significantly higher in protocol-II compared to -I, whereas protocol-III exhibited significantly higher growth factor concentration compared to protocols-I and -II. These findings were observed among 1 and 24 h after clotting, as well as the accumulated growth factor concentration over 24 h. Based on the results, it has been demonstrated that it is possible to enrich PRF-based fluid matrices with leukocytes, platelets and growth factors by means of a single alteration of the centrifugation settings within the clinical routine. We postulate that the so-called low speed centrifugation concept (LSCC) selectively enriches leukocytes, platelets and growth factors within fluid PRF-based matrices. Further studies are needed to evaluate the effect of cell and growth factor enrichment on wound healing and tissue regeneration while comparing blood concentrates gained by high and low RCF.

  13. Error estimation and parameter dependence of the calculation of the fast ion distribution function, temperature, and density using data from the KF1 high energy neutral particle analyzer on Joint European Torus

    International Nuclear Information System (INIS)

    Schlatter, Christian; Testa, Duccio; Cecconello, Marco; Murari, Andrea; Santala, Marko

    2004-01-01

    Joint European Torus high energy neutral particle analyzer measures the flux of fast neutrals originating from the plasma core. From this data, the fast ion distribution function f i fast , temperature T i,perpendicular fast , and density n i fast are derived using knowledge of various plasma parameters and of the cross section for the required atomic processes. In this article, a systematic sensitivity study of the effect of uncertainties in these quantities on the evaluation of the neutral particle analyzer f i fast , T i,perpendicular fast , and n i fast is reported. The dominant parameter affecting n i fast is the impurity confinement time and therefore a reasonable estimate of this quantity is necessary to reduce the uncertainties in n i fast below 50%. On the other hand, T i,perpendicular fast is much less sensitive and can certainly be provided with an accuracy of better than 10%

  14. Effects of different centrifugation conditions on clinical chemistry and Immunology test results

    Directory of Open Access Journals (Sweden)

    Nesic Predrag

    2011-05-01

    Full Text Available Abstract Background The effect of centrifugation time of heparinized blood samples on clinical chemistry and immunology results has rarely been studied. WHO guideline proposed a 15 min centrifugation time without citing any scientific publications. The centrifugation time has a considerable impact on the turn-around-time. Methods We investigated 74 parameters in samples from 44 patients on a Roche Cobas 6000 system, to see whether there was a statistical significant difference in the test results among specimens centrifuged at 2180 g for 15 min, at 2180 g for 10 min or at 1870 g for 7 min, respectively. Two tubes with different plasma separators (both Greiner Bio-One were used for each centrifugation condition. Statistical comparisons were made by Deming fit. Results Tubes with different separators showed identical results in all parameters. Likewise, excellent correlations were found among tubes to which different centrifugation conditions were applied. Fifty percent of the slopes lay between 0.99 and 1.01. Only 3.6 percent of the statistical tests results fell outside the significance level of p Conclusion A centrifugation time of either 7 or 10 min provided identical test results compared to the time of 15 min as proposed by WHO under the conditions used in our study.

  15. Nuclear elasticity applied to giant resonances of fast rotating nuclei

    International Nuclear Information System (INIS)

    Jang, S.; Bouyssy, A.

    1987-06-01

    Isoscalar giant resonances in fast rotating nuclei are investigated within the framework of nuclear elasticity by solving the equation of motion of elastic nuclear medium in a rotating frame of reference. Both Coriolis and centrifugal forces are taken into account. The nuclear rotation removes completely the azimuthal degeneracy of the giant resonance energies. Realistic large values of the angular velocity, which are still small as compared to the giant resonance frequencies, are briefly reviewed in relation to allowed high angular momenta. It is shown that for the A=150 region, the Coriolis force is dominating for small values (< ∼ 0.05) of the ratio of angular velocity to resonance frequency, whereas the centrifugal force plays a prominent part in the shift of the split resonance energies for larger values of the ratio. Typical examples of the resonance energies and their fragmentation due to both rotation and deformation are given

  16. A ‘smart’ tube holder enables real-time sample monitoring in a standard lab centrifuge

    Science.gov (United States)

    Hoang, Tony; Moskwa, Nicholas

    2018-01-01

    The centrifuge is among the oldest and most widely used pieces of laboratory equipment, with significant applications that include clinical diagnostics and biomedical research. A major limitation of laboratory centrifuges is their “black box” nature, limiting sample observation to before and after centrifugation. Thus, optimized protocols require significant trial and error, while unoptimized protocols waste time by centrifuging longer than necessary or material due to incomplete sedimentation. Here, we developed an instrumented centrifuge tube receptacle compatible with several commercial benchtop centrifuges that can provide real-time sample analysis during centrifugation. We demonstrated the system by monitoring cell separations during centrifugation for different spin speeds, concentrations, buffers, cell types, and temperatures. We show that the collected data are valuable for analytical purposes (e.g. quality control), or as feedback to the user or the instrument. For the latter, we verified an adaptation where complete sedimentation turned off the centrifuge and notified the user by a text message. Our system adds new functionality to existing laboratory centrifuges, saving users time and providing useful feedback. This add-on potentially enables new analytical applications for an instrument that has remained largely unchanged for decades. PMID:29659624

  17. Implementation of centrifuge testing of expansive soils for pavement design.

    Science.gov (United States)

    2017-03-01

    The novel centrifuge-based method for testing of expansive soils from project 5-6048-01 was implemented into : use for the determination of the Potential Vertical Rise (PVR) of roadways that sit on expansive subgrades. The : centrifuge method was mod...

  18. Centrifugal compressor design options for small turbochargers

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, C. [ITC, San Diego (United States)

    1998-07-01

    Evolutionary development of the small turbocharger centrifugal compressor over the past four decades has resulted in a finely honed turbomachinery component satisfying both thermodynamic and economic constraints. At this penultimate stage of development an appraisal was considered timely of the remaining design options that exist to enhance the performance characteristics and cost reduction features. This paper presents the results of an analytical study of various small centrifugal compressor design options, assessed in merit of both aerodynamic and manufacturing cost attributes, together with recommendations for future research avenues. (author)

  19. The Maryland Centrifugal Experiment (MCX): Centrifugal Confinement and Velocity Shear Stabilization of Plasmas in Shaped Open Magnetic Systems

    International Nuclear Information System (INIS)

    Hassam, Adil; Ellis, Richard F.

    2012-01-01

    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 up to 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.

  20. Modeling industrial centrifugation of mammalian cell culture using a capillary based scale-down system.

    Science.gov (United States)

    Westoby, Matthew; Rogers, Jameson K; Haverstock, Ryan; Romero, Jonathan; Pieracci, John

    2011-05-01

    Continuous-flow centrifugation is widely utilized as the primary clarification step in the recovery of biopharmaceuticals from cell culture. However, it is a challenging operation to develop and characterize due to the lack of easy to use, small-scale, systems that can be used to model industrial processes. As a result, pilot-scale continuous centrifugation is typically employed to model large-scale systems requiring a significant amount of resources. In an effort to reduce resource requirements and create a system which is easy to construct and utilize, a capillary shear device, capable of producing energy dissipation rates equivalent to those present in the feed zones of industrial disk stack centrifuges, was developed and evaluated. When coupled to a bench-top, batch centrifuge, the capillary device reduced centrate turbidity prediction error from 37% to 4% compared to using a bench-top centrifuge alone. Laboratory-scale parameters that are analogous to those routinely varied during industrial-scale continuous centrifugation were identified and evaluated for their utility in emulating disk stack centrifuge performance. The resulting relationships enable bench-scale process modeling of continuous disk stack centrifuges using an easily constructed, scalable, capillary shear device coupled to a typical bench-top centrifuge. Copyright © 2010 Wiley Periodicals, Inc.

  1. Detection of outliers in a gas centrifuge experimental data

    Directory of Open Access Journals (Sweden)

    M. C. V. Andrade

    2005-09-01

    Full Text Available Isotope separation with a gas centrifuge is a very complex process. Development and optimization of a gas centrifuge requires experimentation. These data contain experimental errors, and like other experimental data, there may be some gross errors, also known as outliers. The detection of outliers in gas centrifuge experimental data is quite complicated because there is not enough repetition for precise statistical determination and the physical equations may be applied only to control of the mass flow. Moreover, the concentrations are poorly predicted by phenomenological models. This paper presents the application of a three-layer feed-forward neural network to the detection of outliers in analysis of performed on a very extensive experiment.

  2. Comparison of Fast-Food and Non-Fast-Food Children's Menu Items

    Science.gov (United States)

    Serrano, Elena L.; Jedda, Virginia B.

    2009-01-01

    Objective: Compare the macronutrient content of children's meals sold by fast-food restaurants (FFR) and non-fast-food restaurants (NFF). Design: All restaurants within the designated city limits were surveyed. Non-fast-food children's meals were purchased, weighed, and analyzed using nutrition software. All fast-food children's meals were…

  3. Platelet concentration of plateletrich plasma from dogs, obtained through three centrifugation speeds

    Directory of Open Access Journals (Sweden)

    Vanessa Couto de Magalhães Ferraz

    2007-12-01

    Full Text Available The platelets release at least 4 growth factors (Platelet Derived Growth Factor. ²1 and ²2 Transforming Growth Factors and Insulin-like Growth Factor which are responsible for the migration and activation of cells that will start the reparation of soft tissues and bones. The Platelet Rich Plasma is an autogenous source for Growth Factors, obtained by platelet concentration by centrifuging total blood. This study aimed the comparison of platelet concentrations in plasma centrifuged in three different centrifugation speeds (1300, 1600 e 3200rpm, for the production of platelet rich plasma. Blood was drowned from 15 dogs, 40ml of each, and these were divided into four groups and centrifuged at 800rpm. Then the first group was centrifuged at 1300rpm, the second at 1600rpm, the third at 3200rpm and the last was used as control, named plasma. The mean percentage increase in the platelet concentration for each technique was: 1300 - 183%, 1600 - 210% and 3200 - 222%. But in centrifugation at 3200 rpm, platelets presented altered morphology and different sizes in every sample studied, which was understood as severe cell damage. It was concluded that the best technique for the preparation of the platelet rich plasma in dogs consisted of the previous centrifugation of the blood at 800rpm for ten minutes, and then the plasma should be separated. This plasma is then submitted to a second centrifugation of 1600rpm for 10 minutes, and the platelet poor plasma is separated and discharged.

  4. Guided imagery, anxiety, heart rate, and heart rate variability during centrifuge training.

    Science.gov (United States)

    Jing, Xiaolu; Wu, Ping; Liu, Fang; Wu, Bin; Miao, Danmin

    2011-02-01

    Centrifuge training is an important method of improving the hypergravity tolerance of pilots, cosmonauts, and Chinese astronauts. However, the concomitants of tension or anxiety often impede training. Guided imagery (GI), a mind-body relaxation technique, provides a behavioral and cognitive means whereby individuals are able to exert control over the focus of attention. This study aims to investigate the immediate effects of GI for reducing stress in centrifuge training. There were 12 healthy young men who were randomly assigned to a GI group or music group. We measured changes in heart rate during centrifuge training, in heart rate variability before and after centrifuge training, and also evaluated relaxation and anxiety in three phases: before intervention, after intervention, and following centrifuge training. The change in the pattern of anxiety was different in the two groups over the three phases. Anxiety (measured by State Anxiety Inventory) in the GI group changed from 31.7 +/- 5.9 to 26.8 +/- 2.6 and 27.8 +/- 4.1, whereas for the music group this changed from 32.2 +/- 7.6 to 31.2 +/- 8.3 and 26.8 +/- 6.8. During centrifuge training, the maximal HR for the GI group (101.2 +/- 8.8) was lower than that of the music group (123.0 +/- 19.1). In addition GI showed a decrease in low frequency (LF, 0.04-0.15 Hz) components and an increase in high frequency (HF, 0.15-0.4 Hz) components before and after centrifuge training. GI was capable of decreasing tension, anxiety, and sympathetic nervous system activity pre- or post-centrifugation.

  5. Fluorimetric methods for the measurement of intermediate metabolites (lactate, pyruvate, alanine, beta-hydroxybutyrate, glycerol) using a COBAS FARA centrifugal analyser.

    Science.gov (United States)

    Monti, L D; Sandoli, P E; Costa, S; Phan, V C; Piatti, P M

    1993-01-01

    Intermediate products of the metabolism of glucose, fat and amino-acid are important in the evaluation of such metabolic disorders as diabetes mellitus, liver disease and metabolic acidosis. In the present study, methods for the measurement of intermediate metabolites (lactate, pyruvate, alanine, beta-hydroxybutyrate and glycerol) have been adapted to a fast centrifugal analyzer: the COBAS FARA. Correlation coeffcients rangedfrom 0.90 to 0.99, compared to established manual spectrophotometric methods. Within-run coeffcients of variation (CVs) ranged between 2.9 and 8.8% at low levels, between 1.5 and 5.7% at medium levels and between 1.2 and 5.6% at high levels. Between-run CVs were between 4.0 and 15.0% at low levels, between 1.7 and 7.0% at medium levels and between 1.3 and 2.7% at high levels. These fluorimetric assays for the determination of intermediate metabolites on COBAS FARA (Roche) have a good sensitivity and precision, are less costly than manual methods and can be used on a routine basis.

  6. Uranium enrichment by centrifuge in Japan

    International Nuclear Information System (INIS)

    Watanabe, T.; Murase, T.

    1977-01-01

    The demand for enriched uranium is on the increase with nuclear power capacity in which the LWR predominates and is estimated to exceed the supply from the present facilities in the world in less than ten years. Therefore, the basic strategy for enriched uranium is investigated on the following three-point long-range program in Japan: 1. To continue negotiations to extend the current allocation by the long-term contract; 2. To seek active participation in international enrichment projects; and 3. To make efforts to develop uranium enrichment technology and to construct inland facilities. On this basis, a vigorous development program of gas centrigue process for industrialization was launched out in 1972 as a national project. Ever since substantial progress in this field has been made and development works have been increased year after year. At present, a concrete plan of a pilot plant is taking shape. Up to now, several types of centrifuges were developed, of which some were completed as prototype models, and subjected to life tests and also to extensive earthquake-resistivity tests for the characteristics of Japanese geological condition. An enrichment plant is composed of so many centrifuges that the installation and piping system of centrifuges is an important factor which has an effect on plant economy and reliability. Two types of the experimental cascade were constructed in Japan. One has been in operation since 1973, and the other since 1975. Valuable empirical data have been accumulated on cascade characteristics, maintenance scheme and so on. It will be important for the coming plants to have a flexibility to escalation of labor and energy cost, or to variation of the separative work requirement and further. An economic prospect of centrifuge enrichment process is presented

  7. Quasi-conical centrifugal ion trap

    International Nuclear Information System (INIS)

    Golikov, Yu.K.; Solov'ev, K.V.; Grigor'ev, D.V.; Flegontova, E.Yu.

    1999-01-01

    This paper describes a new excellent ion trap that principally differs from the classic hyperbolic one by its action. The action is based on the axisymmetric electrostatic quasi-conical field with the following potential type: F=F 0 [ln r - r 2 /2+z 2 ], where r, z are cylindrical dimensionless coordinates. The radial potential run (f=ln r-r 2 /2), in this case, is exactly presented by the approximation function f a =ar 2 +b/r 2 +c. In addition, there are some ranges of r (for example, 0.6< r<0.35), in which the concurrence accuracy value is above 0.5%. The paper presents the theory of particles dynamics in the centrifugal trap. Basic correlation for resolution ratios and sensitivity values are developed. Recommendations on the centrifugal trap design implementation, including the recording system, are given

  8. Sludge behavior in centrifugal contactor operation for nuclear fuel reprocessing

    International Nuclear Information System (INIS)

    Sakamoto, Atsushi; Sano, Yuichi; Takeuchi, Masayuki; Okamura, Nobuo; Koizumi, Kenji

    2015-01-01

    The Japan Atomic Energy Agency (JAEA) has been developing the centrifugal contactor for spent fuel reprocessing. In this study, we investigated the sludge behavior in centrifugal contactors at three different scales. The operational conditions (the flow rate and rotor speed) were varied. Most insoluble particles such as sludge remained in the rotor via centrifugal force. The capture ratio of sludge in the contactor was measured as a function of particle size at various flow rates, rotor speeds, and contactor scales. The sludge adhered and accumulated inside the rotor as the operational time increased, and the operational conditions influenced the capture ratio of the sludge; a lower flow rate and higher rotor speed increased the capture ratio. The results confirmed that Stokes' law can be applied to estimate the experimental result on the behavior of the capture ratio for centrifugal contactors with different scales. (author)

  9. Differential centrifugation of leucocytes and platelets applied to 111In-leucocyte labelling

    International Nuclear Information System (INIS)

    Mountford, P.J.

    1986-01-01

    Platelet contamination of 111 In-leucocytes can be minimized by centrifugation of leucocyte-rich plasma before labelling. The differential recovery of leucocytes and platelets from centrifugation depends on various biological and physical factors. Experimental measurements have been made of the effect of some of these factors. The ratio of leucocyte-to-platelet recovery was increased by using more than one centrifugation, and by using a low relative centrifugal force (RCF). To extend the study, a method of calculating cell recovery from centrifugation was developed, based on the experimental results. Calculations indicated that this ratio was at a maximum at around 85g RCF, and was least affected by changes in the suspension medium viscosity. At 85g, leucocyte recovery was incomplete, but calculations indicated that there was a preferential recovery of granulocytes which was subsequently verified by experiment. (author)

  10. Instability of a Vacuum Arc Centrifuge

    International Nuclear Information System (INIS)

    Hole, M.J.; Dallaqua, R.S.; Bosco, E. del; Simpson, S.W.

    2003-01-01

    Ever since conception of the Vacuum Arc Centrifuge (VAC) in 1980, periodic fluctuations in the ion saturation current and floating potential have been observed in Langmuir probe measurements in the rotation region of a VAC. Our theoretical and experimental research suggests that these fluctuations are in fact a pressure-gradient driven drift mode. In this work, we summarise the properties of a theoretical model describing the range of instabilities in the VAC plasma column, present theoretical predictions and compare with detailed experiments conducted on the PCEN centrifuge at the Brazilian National Space Research Institute (INPE). We conclude that the observed instability is a 'universal' instability, driven by the density-gradient, in a plasma with finite conductivity

  11. Centrifugal blood pump 603

    Indian Academy of Sciences (India)

    Centrifugal blood pump 603 pressure obtained for real blood, as shown in figure 6, is a little higher than that for glycerin aqua Solution with the same viscosity as blood. This may indicate the effect of slight non-. Newtonian turbulent flow. The radial whirl motion of the impeller was observed by dual laser position sensors.

  12. A Comparison of Lignin, Macroalgae, Wood and Straw Fast Pyrolysis

    DEFF Research Database (Denmark)

    Trinh, Ngoc Trung; Jensen, Peter Arendt; Dam-Johansen, Kim

    2013-01-01

    these biomasses. The fast pyrolysis of macroalgae showed a promising result with a bio-oil yield of 65 wt% dry ash free basis (daf) and 76 % energy recovery in the bio-oil while the lignin fast pyrolysis provides a bio-oil yield of 47 wt% daf and energy recovery in bio-oil of 45 %. The physiochemical properties...... of the bio-oils were characterized with respect to higher heating value (HHV), molecular mass distribution, viscosity, pH, density, thermal behaviors, elemental concentrations, phase separation and aging. The lignin and macroalgae oil properties were different compared to those of the wood and straw oils......A fast pyrolysis study on lignin and macroalgae (non-conventional biomass) and wood and straw (conventional biomass) were carried out in a pyrolysis centrifugal reactor at pyrolysis temperature of 550 ºC. The product distributions and energy recoveries were measured and compared among...

  13. A hand-powered, portable, low-cost centrifuge for diagnosing anemia in low-resource settings.

    Science.gov (United States)

    Brown, Jocelyn; Theis, Lauren; Kerr, Lila; Zakhidova, Nazima; O'Connor, Kelly; Uthman, Margaret; Oden, Z Maria; Richards-Kortum, Rebecca

    2011-08-01

    This report describes the development of a hand-powered centrifuge to determine hematocrit values in low-resource settings. A hand-powered centrifuge was constructed by using a salad spinner. Hematocrit values were measured by using the hand-powered device, and results were compared with those of a benchtop centrifuge. The packed cell volume (PCV) measured with the hand-powered device correlated linearly with results obtained with a benchtop centrifuge (r = 0.986, P centrifuge were consistently 1.14 times higher than those measured with the benchtop system. The 14% increase in PCV measured with the hand-powered centrifuge is caused by increased plasma trapped in the cell column. The reader card was adjusted to compensate for trapped plasma. A hand-powered centrifuge and calibrated reader card can be constructed for U.S. $35 and can accurately determine hematocrit values. It is suitable for use in low-resource settings because it is mechanically-powered, inexpensive, and accurate.

  14. Centrifugal shot blast system

    International Nuclear Information System (INIS)

    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

  15. 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. © 2015 Wiley Periodicals, Inc.

  16. Research of plating aluminum and aluminum foil on internal surface of carbon fiber composite material centrifuge rotor drum

    International Nuclear Information System (INIS)

    Lu Xiuqi; Dong Jinping; Dai Xingjian

    2014-01-01

    In order to improve the corrosion resistance, thermal conductivity and sealability of the internal surface of carbon fiber/epoxy composite material centrifuge rotor drum, magnetron sputtering aluminum and pasting an aluminum foil on the inner wall of the drum are adopted to realize the aim. By means of XRD, SEM/EDS and OM, the surface topography of aluminum coated (thickness of 5 μm and 12 μm) and aluminum foil (12 μm) are observed and analyzed; the cohesion of between aluminum coated (or aluminum foil) and substrate material (CFRP) is measured by scratching experiment, direct drawing experiment, and shear test. Besides, the ultra-high-speed rotation experiment of CFRP ring is carried out to analyze stress and strain of coated aluminum (or aluminum foil) which is adhered on the ring. The results showed aluminum foil pasted on inner surface do better performance than magnetron sputtering aluminum on CFRP centrifuge rotor drum. (authors)

  17. Designing and analysis study of uranium enrichment with gas centrifuge

    International Nuclear Information System (INIS)

    Tsunetoshi Kai

    2006-01-01

    This note concerns a designing and analysis study of uranium enrichment with a gas centrifuge. At first, one dimensional model is presented and a conventional analytical method is applied to grasp the general idea of a centrifuge performance. Secondly, two-dimensional numerical method is adopted to describe the diffusion phenomena with assumption of simple flow patterns. Parametric surveys are made on the dimension of a centrifuge rotor, the gas feed, withdrawal and circulation system, and operation variables such as feed flow rate, cut and so on. Thirdly, full numerical solutions are obtained for the flow and diffusion equations in static state, using a modified version of the Newton method without neglect of any non-linear term. The numerical results are compared with the experimental data made by Beams et al. and Zippe, and found to be in good agreement. Further, the theoretical pressure and separative power are compared respectively with experimental ones on a comparatively recent centrifuge. The results reveal that the characteristics of separation performance of a centrifuge can be fully described by the present method. Some of inevitable problems are tackled regarding UF 6 gas isotope separation by centrifugation. To examine the influence of the extraneous light gas, the diffusion equations for ternary mixture are solved and also the flow field of binary mixture with large mass difference is obtained to simultaneously solve the Navier-Stokes equations and the diffusion equation.for binary case. Since the gas in the interior region of the rotor is so rarefied that the Navier-Stokes equations cease to be valid, the Burnett equations are solved.for gas flow in a rotating cylinder. Considering that the uranium recovered at a reprocessing plant includes 236 U besides 235 U and 238 U, the concentration distributions of the ternary gas isotopes are determined and a value function is defined for the evaluation of separative work for the multi-component mixture

  18. Computational fluid dynamics analysis of a maglev centrifugal left ventricular assist device.

    Science.gov (United States)

    Burgreen, Greg W; Loree, Howard M; Bourque, Kevin; Dague, Charles; Poirier, Victor L; Farrar, David; Hampton, Edward; Wu, Z Jon; Gempp, Thomas M; Schöb, Reto

    2004-10-01

    The fluid dynamics of the Thoratec HeartMate III (Thoratec Corp., Pleasanton, CA, U.S.A.) left ventricular assist device are analyzed over a range of physiological operating conditions. The HeartMate III is a centrifugal flow pump with a magnetically suspended rotor. The complete pump was analyzed using computational fluid dynamics (CFD) analysis and experimental particle imaging flow visualization (PIFV). A comparison of CFD predictions to experimental imaging shows good agreement. Both CFD and experimental PIFV confirmed well-behaved flow fields in the main components of the HeartMate III pump: inlet, volute, and outlet. The HeartMate III is shown to exhibit clean flow features and good surface washing across its entire operating range.

  19. Differential white cell count by centrifugal microfluidics.

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, Gregory Jon; Tentori, Augusto M.; Schaff, Ulrich Y.

    2010-07-01

    We present a method for counting white blood cells that is uniquely compatible with centrifugation based microfluidics. Blood is deposited on top of one or more layers of density media within a microfluidic disk. Spinning the disk causes the cell populations within whole blood to settle through the media, reaching an equilibrium based on the density of each cell type. Separation and fluorescence measurement of cell types stained with a DNA dye is demonstrated using this technique. The integrated signal from bands of fluorescent microspheres is shown to be proportional to their initial concentration in suspension. Among the current generation of medical diagnostics are devices based on the principle of centrifuging a CD sized disk functionalized with microfluidics. These portable 'lab on a disk' devices are capable of conducting multiple assays directly from a blood sample, embodied by platforms developed by Gyros, Samsung, and Abaxis. [1,2] However, no centrifugal platform to date includes a differential white blood cell count, which is an important metric complimentary to diagnostic assays. Measuring the differential white blood cell count (the relative fraction of granulocytes, lymphocytes, and monocytes) is a standard medical diagnostic technique useful for identifying sepsis, leukemia, AIDS, radiation exposure, and a host of other conditions that affect the immune system. Several methods exist for measuring the relative white blood cell count including flow cytometry, electrical impedance, and visual identification from a stained drop of blood under a microscope. However, none of these methods is easily incorporated into a centrifugal microfluidic diagnostic platform.

  20. Experimental study of xenon isotopes production by gas centrifuge

    International Nuclear Information System (INIS)

    Zhou Mingsheng; Liang Xiongwen; Zhang Yonggang; Dong Jinping

    2006-01-01

    The gas centrifuge technology is studied for the separation of Xe isotopes. The nature Xe is chosen as processing gas. A four-state cascade is designed to separate 124 Xe to a concentration of being greater than 65% in three separation runs. 124 Xe can be enriched to a concentration 99% in more separation runs using a cascade of more gas centrifuges. (authors)

  1. Separation of gold nanorods by viscosity gradient centrifugation

    International Nuclear Information System (INIS)

    Dong, Suli; Wang, Yawei; Li, Xiaogang; Zhang, Qingquan; Liu, Xiaojun; Tu, Yang; Liang, Aiye

    2016-01-01

    Size-uniform gold nanorods (Au-NRs) are used in biosensing, bioimaging, photothermal therapy, drug and gene delivery, and controlled release. Monodisperse Au-NRs are usually obtained by separation steps following their synthesis, and centrifugation is widely used because of the ease of operation, high recovery, and the good availability of equipment. So far, the effect of viscosity on the separation of Au-NRs has not been investigated. We have developed a method for separation of monodisperse Au-NRs that is based on centrifugation in a viscosity gradient. Monodisperse Au-NRs obtained from gold nanoparticles were obtained by centrifugation in viscosity gradient adjusted with poly(2-ethyl-2-oxazoline). Au-NRs in sizes ranging from 25.6 to 26.1 nm in effective radius can be separated 5500 g within 5 min, which appears to be the fastest method for separation of Au-NRs. (author)

  2. Space Station Centrifuge: A Requirement for Life Science Research

    Science.gov (United States)

    Smith, Arthur H.; Fuller, Charles A.; Johnson, Catherine C.; Winget, Charles M.

    1992-01-01

    A centrifuge with the largest diameter that can be accommodated on Space Station Freedom is required to conduct life science research in the microgravity environment of space. (This was one of the findings of a group of life scientists convened at the University of California, Davis, by Ames Research Center.) The centrifuge will be used as a research tool to understand how gravity affects biological processes; to provide an on-orbit one-g control; and to assess the efficacy of using artificial gravity to counteract the deleterious biological effect of space flight. The rationale for the recommendation and examples of using ground-based centrifugation for animal and plant acceleration studies are presented. Included are four appendixes and an extensive bibliography of hypergravity studies.

  3. Dysrhythmias in Laypersons During Centrifuge-Simulated Suborbital Spaceflight.

    Science.gov (United States)

    Suresh, Rahul; Blue, Rebecca S; Mathers, Charles H; Castleberry, Tarah L; Vanderploeg, James M

    2017-11-01

    There are limited data on cardiac dysrhythmias in laypersons during hypergravity exposure. We report layperson electrocardiograph (ECG) findings and tolerance of dysrhythmias during centrifuge-simulated suborbital spaceflight. Volunteers participated in varied-length centrifuge training programs of 2-7 centrifuge runs over 0.5-2 d, culminating in two simulated suborbital spaceflights of combined +Gz and +Gx (peak +4.0 Gz, +6.0 Gx, duration 5 s). Monitors recorded pre- and post-run mean arterial blood pressure (MAP), 6-s average heart rate (HR) collected at prespecified points during exposures, documented dysrhythmias observed on continuous 3-lead ECG, self-reported symptoms, and objective signs of intolerance on real-time video monitoring. Participating in the study were 148 subjects (43 women). Documented dysrhythmias included sinus pause (N = 5), couplet premature ventricular contractions (N = 4), bigeminy (N = 3), accelerated idioventricular rhythm (N = 1), and relative bradycardia (RB, defined as a transient HR drop of >20 bpm; N = 63). None were associated with subjective symptoms or objective signs of acceleration intolerance. Episodes of RB occurred only during +Gx exposures. Subjects had a higher post-run vs. pre-run MAP after all exposures, but demonstrated no difference in pre- and post-run HR. RB was more common in men, younger individuals, and subjects experiencing more centrifuge runs. Dysrhythmias in laypersons undergoing simulated suborbital spaceflight were well tolerated, though RB was frequently noted during short-duration +Gx exposure. No subjects demonstrated associated symptoms or objective hemodynamic sequelae from these events. Even so, heightened caution remains warranted when monitoring dysrhythmias in laypersons with significant cardiopulmonary disease or taking medications that modulate cardiac conduction.Suresh R, Blue RS, Mathers CH, Castleberry TL, Vanderploeg JM. Dysrhythmias in laypersons during centrifuge-stimulated suborbital

  4. Repurposing a Benchtop Centrifuge for High-Throughput Single-Molecule Force Spectroscopy.

    Science.gov (United States)

    Yang, Darren; Wong, Wesley P

    2018-01-01

    We present high-throughput single-molecule manipulation using a benchtop centrifuge, overcoming limitations common in other single-molecule approaches such as high cost, low throughput, technical difficulty, and strict infrastructure requirements. An inexpensive and compact Centrifuge Force Microscope (CFM) adapted to a commercial centrifuge enables use by nonspecialists, and integration with DNA nanoswitches facilitates both reliable measurements and repeated molecular interrogation. Here, we provide detailed protocols for constructing the CFM, creating DNA nanoswitch samples, and carrying out single-molecule force measurements.

  5. Adiabatic Field-Free Alignment of Asymmetric Top Molecules with an Optical Centrifuge.

    Science.gov (United States)

    Korobenko, A; Milner, V

    2016-05-06

    We use an optical centrifuge to align asymmetric top SO_{2} molecules by adiabatically spinning their most polarizable O-O axis. The effective centrifugal potential in the rotating frame confines the sulfur atoms to the plane of the laser-induced rotation, leading to the planar molecular alignment that persists after the molecules are released from the centrifuge. The 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 deg, permanent field-free alignment offers new ways of controlling molecules with laser light.

  6. Hydraulic and separation characteristics of an industrial gas centrifuge calculated with neural networks

    Science.gov (United States)

    Butov, Vladimir; Timchenko, Sergey; Ushakov, Ivan; Golovkov, Nikita; Poberezhnikov, Andrey

    2018-03-01

    Single gas centrifuge (GC) is generally used for the separation of binary mixtures of isotopes. Processes taking place within the centrifuge are complex and non-linear. Their characteristics can change over time with long-term operation due to wear of the main structural elements of the GC construction. The paper is devoted to the determination of basic operation parameters of the centrifuge with the help of neural networks. We have developed a method for determining the parameters of the industrial GC operation by processing statistical data. In this work, we have constructed a neural network that is capable of determining the main hydraulic and separation characteristics of the gas centrifuge, depending on the geometric dimensions of the gas centrifuge, load value, and rotor speed.

  7. MTA 1527-2000: A fast automatic analyzer for the analysis of mineral raw materials and products of the silicate industry

    International Nuclear Information System (INIS)

    Horvath, H.; Renner, J.; Siklos, A.

    1982-01-01

    A new automatic analytical system designed and constructed for fast measurements on the spot is described. The system can be applied in cars, ships or galleries of mines. It consists of two independent analyzer systems: neutron activation and X-ray fluorescence analyzers. The main purpose of the design was to determine Al, Si, Ca and Fe oxides in bauxite, alumina, clays and in products of the silicate industry, mainly in cements. The measuring and data evaluation processes are fully automated. It can be used for the continuous monitoring and control of cement production. (D.Gy.)

  8. Quantitative Index and Abnormal Alarm Strategy Using Sensor-Dependent Vibration Data for Blade Crack Identification in Centrifugal Booster Fans.

    Science.gov (United States)

    Chen, Jinglong; Sun, Hailiang; Wang, Shuai; He, Zhengjia

    2016-05-09

    Centrifugal booster fans are important equipment used to recover blast furnace gas (BFG) for generating electricity, but blade crack faults (BCFs) in centrifugal booster fans can lead to unscheduled breakdowns and potentially serious accidents, so in this work quantitative fault identification and an abnormal alarm strategy based on acquired historical sensor-dependent vibration data is proposed for implementing condition-based maintenance for this type of equipment. Firstly, three group dependent sensors are installed to acquire running condition data. Then a discrete spectrum interpolation method and short time Fourier transform (STFT) are applied to preliminarily identify the running data in the sensor-dependent vibration data. As a result a quantitative identification and abnormal alarm strategy based on compound indexes including the largest Lyapunov exponent and relative energy ratio at the second harmonic frequency component is proposed. Then for validation the proposed blade crack quantitative identification and abnormality alarm strategy is applied to analyze acquired experimental data for centrifugal booster fans and it has successfully identified incipient blade crack faults. In addition, the related mathematical modelling work is also introduced to investigate the effects of mistuning and cracks on the vibration features of centrifugal impellers and to explore effective techniques for crack detection.

  9. Quantitative Index and Abnormal Alarm Strategy Using Sensor-Dependent Vibration Data for Blade Crack Identification in Centrifugal Booster Fans

    Directory of Open Access Journals (Sweden)

    Jinglong Chen

    2016-05-01

    Full Text Available Centrifugal booster fans are important equipment used to recover blast furnace gas (BFG for generating electricity, but blade crack faults (BCFs in centrifugal booster fans can lead to unscheduled breakdowns and potentially serious accidents, so in this work quantitative fault identification and an abnormal alarm strategy based on acquired historical sensor-dependent vibration data is proposed for implementing condition-based maintenance for this type of equipment. Firstly, three group dependent sensors are installed to acquire running condition data. Then a discrete spectrum interpolation method and short time Fourier transform (STFT are applied to preliminarily identify the running data in the sensor-dependent vibration data. As a result a quantitative identification and abnormal alarm strategy based on compound indexes including the largest Lyapunov exponent and relative energy ratio at the second harmonic frequency component is proposed. Then for validation the proposed blade crack quantitative identification and abnormality alarm strategy is applied to analyze acquired experimental data for centrifugal booster fans and it has successfully identified incipient blade crack faults. In addition, the related mathematical modelling work is also introduced to investigate the effects of mistuning and cracks on the vibration features of centrifugal impellers and to explore effective techniques for crack detection.

  10. Optimisation of a double-centrifugation method for preparation of canine platelet-rich plasma.

    Science.gov (United States)

    Shin, Hyeok-Soo; Woo, Heung-Myong; Kang, Byung-Jae

    2017-06-26

    Platelet-rich plasma (PRP) has been expected for regenerative medicine because of its growth factors. However, there is considerable variability in the recovery and yield of platelets and the concentration of growth factors in PRP preparations. The aim of this study was to identify optimal relative centrifugal force and spin time for the preparation of PRP from canine blood using a double-centrifugation tube method. Whole blood samples were collected in citrate blood collection tubes from 12 healthy beagles. For the first centrifugation step, 10 different run conditions were compared to determine which condition produced optimal recovery of platelets. Once the optimal condition was identified, platelet-containing plasma prepared using that condition was subjected to a second centrifugation to pellet platelets. For the second centrifugation, 12 different run conditions were compared to identify the centrifugal force and spin time to produce maximal pellet recovery and concentration increase. Growth factor levels were estimated by using ELISA to measure platelet-derived growth factor-BB (PDGF-BB) concentrations in optimised CaCl 2 -activated platelet fractions. The highest platelet recovery rate and yield were obtained by first centrifuging whole blood at 1000 g for 5 min and then centrifuging the recovered platelet-enriched plasma at 1500 g for 15 min. This protocol recovered 80% of platelets from whole blood and increased platelet concentration six-fold and produced the highest concentration of PDGF-BB in activated fractions. We have described an optimised double-centrifugation tube method for the preparation of PRP from canine blood. This optimised method does not require particularly expensive equipment or high technical ability and can readily be carried out in a veterinary clinical setting.

  11. Cavitation simulation and NPSH prediction of a double suction centrifugal pump

    International Nuclear Information System (INIS)

    Li, P; Huang, Y F; Li, J

    2012-01-01

    This paper illustrates the flow field numerical analysis of the double-suction centrifugal pump. For the study of the cavitation flow inside the double-suction centrifugal pump, the professional pump/motor simulation software PumpLinx and its Full Cavitation Model has been employed. According to the PumpLinx calculation result and the Cavitation damage index, the cavitation position, level and the cavitation characteristics of the double-suction centrifugal pump has been predicted. For the further objective, the simulation of the flow field in the double-suction centrifugal pump under different inlet conditions has been carried out. By the result analysis, NPSHr has been predicted; the reliability of the results has been verified by comparing with the experimental data. At the same time, this practice can provide guidance for the optimal design of double-suction pump.

  12. Numerical analysis of the internal flow field in screw centrifugal blood pump based on CFD

    Science.gov (United States)

    Han, W.; Han, B. X.; Y Wang, H.; Shen, Z. J.

    2013-12-01

    As to the impeller blood pump, the high speed of the impeller, the local high shear force of the flow field and the flow dead region are the main reasons for blood damage. The screw centrifugal pump can effectively alleviate the problems of the high speed and the high shear stress for the impeller. The softness and non-destructiveness during the transfer process can effectively reduce the extent of the damage. By using CFD software, the characteristics of internal flow are analyzed in the screw centrifugal pump by exploring the distribution rules of the velocity, pressure and shear deformation rate of the blood when it flows through the impeller and the destructive effects of spiral blades on blood. The results show that: the design of magnetic levitation solves the sealing problems; the design of regurgitation holes solves the problem of the flow dead zone; the magnetic levitated microcirculation screw centrifugal pump can effectively avoid the vortex, turbulence and high shear forces generated while the blood is flowing through the pump. Since the distribution rules in the velocity field, pressure field and shear deformation rate of the blood in the blood pump are comparatively uniform and the gradient change is comparatively small, the blood damage is effectively reduced.

  13. Seismic soil-structure interaction: Analysis and centrifuge model studies

    International Nuclear Information System (INIS)

    Finn, W.D.L.; Ledbetter, R.H.; Beratan, L.L.

    1986-01-01

    A method for nonlinear dynamic effective stress analysis applicable to soil-structure interaction problems is introduced. Full interaction including slip between structure and foundation is taken into account and the major factors that must be considered when computing dynamic soil response are included. An experimental investigation using simulated earthquake tests on centrifuged geotechnical models was conducted to obtain prototype response data of foundation soils carrying both surface and embedded structures and to validate the dynamic effective stress analysis. The centrifuge tests were conducted in the Geotechnical Centrifuge at Cambridge University, England. Horizontal and vertical accelerations were measured at various points on structures and in the sand foundation. Seismically induced pore water pressure changes were also measured at various locations in the foundation. Computer plots of the data were obtained while the centrifuge was in flight and representative samples are presented. The results clearly show the pronounced effect of increasing pore water pressures on dynamic response. It is demonstrated that a coherent picture of dynamic response of soil-structure systems is provided by dynamic effective stress nonlinear analysis. On the basis of preliminary results, it appears that the effects of pore water pressure can be predicted. (orig.)

  14. Subject anxiety and psychological considerations for centrifuge-simulated suborbital spaceflight.

    Science.gov (United States)

    Mulcahy, Robert A; Blue, Rebecca S; Vardiman, Johnené L; Mathers, Charles H; Castleberry, Tarah L; Vanderploeg, James M

    2014-08-01

    Anxiety and psychological concerns may pose a challenge to future commercial spaceflight. To help identify potential measures of anxiousness and indicators of flight-related stress, the psychiatric histories and anxiousness responses of volunteers exposed to G forces in centrifuge-simulated spaceflight acceleration profiles were examined. Over 2 d, 86 individuals (63 men, 23 women), 20-78 yr old, underwent up to 7 centrifuge runs. Day 1 consisted of two +G(z) runs (peak = +3.5 G(z)) and two +Gx runs (peak = +6.0 G(x)). Day 2 consisted of three runs approximating suborbital spaceflight profiles (combined +G(x) and +G(z)). Hemodynamic data were collected during the profiles. Subjects completed a retrospective self-report anxiety questionnaire. Medical monitors identified individuals exhibiting varying degrees of anxiousness during centrifuge exposure, medical histories of psychiatric disease, and other potential indicators of psychological intolerance of spaceflight. The retrospective survey identified 18 individuals self-reporting anxiousness, commonly related to unfamiliarity with centrifuge acceleration and concerns regarding medical history. There were 12 individuals (5 men, 7 women, average age 46.2 yr) who were observed to have anxiety that interfered with their ability to complete training; of these, 4 reported anxiousness on their questionnaire and 9 ultimately completed the centrifuge profiles. Psychiatric history was not significantly associated with anxious symptoms. Anxiety is likely to be a relevant and potentially disabling problem for commercial spaceflight participants; however, positive psychiatric history and self-reported symptoms did not predict anxiety during centrifuge performance. Symptoms of anxiousness can often be ameliorated through training and coaching. Even highly anxious individuals are likely capable of tolerating commercial spaceflight.

  15. Centrifugation: an important pre-analytic procedure that influences plasma microRNA quantification during blood processing.

    Science.gov (United States)

    Zheng, Xiao-Hui; Cui, Cui; Zhou, Xin-Xi; Zeng, Yi-Xin; Jia, Wei-Hua

    2013-12-01

    Circulating microRNAs are robustly present in plasma or serum and have become a research focus as biomarkers for tumor diagnosis and prognosis. Centrifugation is a necessary procedure for obtaining high-quality blood supernatant. Herein, we investigated one-step and two-step centrifugations, two centrifugal methods routinely used in microRNA study, to explore their effects on plasma microRNA quantification. The microRNAs obtained from one-step and two-step centrifugations were quantified by microarray and TaqMan-based real-time quantitative polymerase chain reaction (Q-PCR). Dynamic light scattering was performed to explore the difference underlying the two centrifugal methods. The results from the microarray containing 1,347 microRNAs showed that the signal detection rate was greatly decreased in the plasma sample prepared by two-step centrifugation. More importantly, the microRNAs missing in this plasma sample could be recovered and detected in the precipitate generated from the second centrifugation. Consistent with the results from microarray, a marked decrease of three representative microRNAs in two-step centrifugal plasma was validated by Q-PCR. According to the size distribution of all nanoparticles in plasma, there were fewer nanoparticles with size >1,000 nm in two-step centrifugal plasma. Our experiments directly demonstrated that different centrifugation methods produced distinct quantities of plasma microRNAs. Thus, exosomes or protein complexes containing microRNAs may be involved in large nanoparticle formation and may be precipitated after two-step centrifugation. Our results remind us that sample processing methods should be first considered in conducting research.

  16. Continuous centrifuge decelerator for polar molecules.

    Science.gov (United States)

    Chervenkov, S; Wu, X; Bayerl, J; Rohlfes, A; Gantner, T; Zeppenfeld, M; Rempe, G

    2014-01-10

    Producing large samples of slow molecules from thermal-velocity ensembles is a formidable challenge. Here we employ a centrifugal force to produce a continuous molecular beam with a high flux at near-zero velocities. We demonstrate deceleration of three electrically guided molecular species, CH3F, CF3H, and CF3CCH, with input velocities of up to 200  m s(-1) to obtain beams with velocities below 15  m s(-1) and intensities of several 10(9)  mm(-2) s(-1). The centrifuge decelerator is easy to operate and can, in principle, slow down any guidable particle. It has the potential to become a standard technique for continuous deceleration of molecules.

  17. Studies of the impact of prerotation problem of the secondary impeller on performance of multi-stage centrifugal pumps

    International Nuclear Information System (INIS)

    Zhai, L L; Wu, P; Jiang, Q L; Wang, L Q

    2012-01-01

    In engineering practice, part of the multi-stage centrifugal pumps is designed without space guide vanes due to the size restrictions and the volute is distorted much in shape. In these pumps, tangential velocity of the fluid at the outlet of the first-stage impeller is so great that it has caused a prerotation problem which will affect the inlet flow conditions of the secondary impeller leading to serious efficiency and head decline of the secondary impeller. The head problem of the second stage in multi-stage centrifugal pumps caused by prerotation at the entrance of the second stage was analyzed and the internal hydraulic performance was optimized by setting clapboards in the volute in this paper. CFD numerical simulation method combined with experiment was applied to predict the effect of internal clapboards on the performance of the centrifugal pump. The original prototype was transformed according to the simulation result and tested to verify the optimization work. The experiment result shows that hydraulic performance is remarkably improved compared with the original one and the prerotation problem is basically solved.

  18. Design of ideal cascades of gas centrifuges with variable separation factors

    International Nuclear Information System (INIS)

    Olander, D.R.

    1976-01-01

    A method of designing ideal cascades in which the separation factor varies with stage number is presented and applied to centrifuges as separating units. The centrifuge is characterized by a performance function, which gives the separative power, optimized with respect to all internal variables, as a function of cut and throughput. For centrifuges with certain types of performance functions, variable-α ideal cascades can provide a product at a lower cost than the conventional ideal cascade in which the separation factor is independent of stage number

  19. Sand characterization by combined centrifuge and laboratory tests

    OpenAIRE

    GAUDIN, C; SCHNAID, F; GARNIER, J

    2005-01-01

    The purpose of this paper is to evaluate new methods of interpretation of in situ tests in sand from correlations established from centrifuge and laboratory data. Emphasis is given to methods that are based on the combination of measurements from independent tests, such as the ratio of the elastic stiffness to ultimate strenght and the ratio of cone resistance and limit pressure. For that purpose, a series of centrifuge tests using a cone penetrometer and a cone pressuremeter was carried out ...

  20. Study on flow fields in high specific speed centrifugal compressor with unpinched vaneless diffuser

    International Nuclear Information System (INIS)

    Tamaki, Hideaki

    2013-01-01

    Performance of centrifugal compressors strongly depends on their internal flow fields. CFD has become indispensable tool for getting the information about flow fields in centrifugal compressors. CFD codes are usually validated by some representative data or compared with calculated results by other CFD codes, in order to ensure their accuracies. However, learning their accuracies for all types of centrifugal compressor's specifications requires continuous works that compare experimental data obtained in developmental processes of various types of centrifugal compressors with CFD results. A prediction of a performance and a flow field of a centrifugal compressor by CFD is relatively accurate when the impact of separation and secondary flow on that flow field is weak, i.e. near design condition. Centrifugal compressors are deemed to have a wide operating range alongside high efficiencies at design points. Hence the prediction accuracy of CFD at off design conditions, where the impacts of separation and secondary flow on the flow field are strong, is critical for the design of the centrifugal compressors. This study therefore investigated the prediction accuracy of CFD using a centrifugal compressor whose geometry was intentionally changed to have a distorted flow field over a whole operating range, i.e. from choke to surge.

  1. Study on flow fields in high specific speed centrifugal compressor with unpinched vaneless diffuser

    Energy Technology Data Exchange (ETDEWEB)

    Tamaki, Hideaki [IHI Corporation, Yokoham (Japan)

    2013-06-15

    Performance of centrifugal compressors strongly depends on their internal flow fields. CFD has become indispensable tool for getting the information about flow fields in centrifugal compressors. CFD codes are usually validated by some representative data or compared with calculated results by other CFD codes, in order to ensure their accuracies. However, learning their accuracies for all types of centrifugal compressor's specifications requires continuous works that compare experimental data obtained in developmental processes of various types of centrifugal compressors with CFD results. A prediction of a performance and a flow field of a centrifugal compressor by CFD is relatively accurate when the impact of separation and secondary flow on that flow field is weak, i.e. near design condition. Centrifugal compressors are deemed to have a wide operating range alongside high efficiencies at design points. Hence the prediction accuracy of CFD at off design conditions, where the impacts of separation and secondary flow on the flow field are strong, is critical for the design of the centrifugal compressors. This study therefore investigated the prediction accuracy of CFD using a centrifugal compressor whose geometry was intentionally changed to have a distorted flow field over a whole operating range, i.e. from choke to surge.

  2. [Effect of Parasep® feces centrifuge tube method on detecting schistosome eggs].

    Science.gov (United States)

    Ma, Nian; Zhang, Hua-ming; Liu, Xiong; Xiao, Chuan-yun; Wen, Xiao-hong; Li, Xia; Dong, Li-chun; Cui, Cai-xia; Tu, Zu-wu

    2014-08-01

    To evaluate the effect of the Parasep® feces centrifuge tube method on detecting schistosome eggs. A total of 803 residents aged from 6-65 years were selected in 2 schistosomiasis endemic villages, Jiangling County, Hubei Province, and their stool samples were collected and detected parallelly by the Kato-Katz technique, nylon silk egg hatching method, and Parasep® feces centrifuge tube method at the same time. Among the 803 people, 15 cases were found of schistosome egg positive, and the positive rate was 1.87%. The positive rates of the Kato-Katz technique, nylon silk egg hatching method, and Parasep® feces centrifuge tube method were 0.75%, 1.49% and 1.12%, respectively. The schistosome eggs got with the Parasep® feces centrifuge tube method were clear and easy to identify. In low endemic areas of schistosomiasis, the Parasep® feces centrifuge tube method can be used as schistosomiasis japonica etiology diagnosis method.

  3. 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.

  4. Runtime and Inversion Impacts on Estimation of Moisture Retention Relations by Centrifuge

    Science.gov (United States)

    Sigda, J. M.; Wilson, J. L.

    2003-12-01

    Standard laboratory methods in soil physics for measuring the moisture retention relation (drainage matric potential-volumetric moisture content relation) are each limited to only part of the moisture content range. Centrifuge systems allow intensive accurate measurements across much of the saturation range, and typically require much less time than traditional laboratory methods. An initially liquid-saturated sample is subjected to a stepwise-increasing series of angular velocities while carefully monitoring changes in liquid content. Angular velocity is held constant until the capillary and centrifugal forces equilibrate, forcing liquid flux to zero, and then a final average liquid content is noted. The procedure is repeated after increasing the angular velocity. Centrifuge measurement time is greatly reduced because the centrifugal body force gradient can far exceed the driving forces utilized in standard lab methods. Widely-used in the petroleum industry for decades, centrifuge measurement of moisture retention relations is seldom encountered in the soil physics or vadose hydrology literatures. Yet there is a need to better understand and improve the experimental methodology given the increasing number of centrifuges employed in these fields. Errors in centrifuge measurement of moisture retention relations originate from both experimental protocol and from data inversion. Like standard methods, centrifuge methods assume equilibrium conditions, and so are sensitive to errors introduced by insufficient runtimes. Unlike standard methods, centrifuge experiments require inversion of the angular velocity and average sample moisture content data to a location-specific pair of matric potential and moisture content values, The force balance causes matric potential and moisture content to vary with sample length while the sample is spinning. Numerous data inversion techniques exist, each yielding different moisture retention relations. We present analyses demonstrating

  5. Effects of Impeller-Diffuser Interaction on Centrifugal Compressor Performance

    Science.gov (United States)

    Tan, Choon S.

    2003-01-01

    This research program focuses on characterizing the effect of impeller-diffuser interactions in a centrifugal compressor stage on its performance using unsteady threedimensional Reynolds-averaged Navier-Stokes simulations. The computed results show that the interaction between the downstream diffuser pressure field and the impeller tip clearance flow can account for performance changes in the impeller. The magnitude of performance change due to this interaction was examined for an impeller with varying tip clearance followed by a vaned or vaneless diffuser. The impact of unsteady impeller-diffuser interaction, primarily through the impeller tip clearance flow, is reflected through a time-averaged change in impeller loss, blockage and slip. The results show that there exists a tip clearance where the beneficial effect of the impeller-diffuser interaction on the impeller performance is at a maximum. A flow feature that consists of tip flow back leakage was shown to occur at design speed for the centrifugal compressor stage. This flow phenomenon is described as tip flow that originates in one passage, flows downstream of the impeller trailing edge and then returns to upstream of the impeller trailing edge of a neighboring passage. Such a flow feature is a source of loss in the impeller. A hypothesis is put forth to show that changing the diffuser vane count and changing impeller-diffuser gap has an analogous effect on the impeller performance. The centrifugal compressor stage was analyzed using diffusers of different vane counts, producing an impeller performance trend similar to that when the impeller-diffuser gap was varied, thus supporting the hypothesis made. This has the implication that the effect impeller performance associated with changing the impeller-diffuser gap and changing diffuser vane count can be described by the non-dimensional ratio of impeller-diffuser gap to diffuser vane pitch. A procedure is proposed and developed for isolating impeller passage

  6. The influence of aerosol density upon the performance of centrifugal spectrometers

    International Nuclear Information System (INIS)

    Martonen, T.B.

    1978-01-01

    Centrifugal instruments are valuable components for studying airborne particulate matter of health physics interest because a continuously graded aerodynamic diameter, Dae, spectrum is produced. Applications include the characterization of inhalation exposure aerosols, serving as particle monitors to measure respirable dose, and being the integral unit in a system to generate monodisperse aerosols. Some aerosols of health physics concern differ from the PSL aerosol used to calibrate centrifuges in two main respects: the particulate mass concentration, Cm, is large, and the aerosol gas is not air. The marked influence of these factors upon centrifuge performance is documented (T. B. Martonen, Ph.D. Thesis, University of Rochester, Rochester, NY, 1976). The phenomenon of cloud settling occurs when Cm is of sufficient magnitude. Aerosol gas effects can be defined in terms of the parameter K, the ratio of the aerosol gas to winnowing medium densities. Size classification is modified by diffusiophoretic forces when K 1. In all cases, erroneous size distribution data results. Laboratory procedures are presented which permit accurate particle size assessment when aerosols of large Cm and/or K≠1 are sampled. An engineering analysis of centrifuge physics has been completed which allows optimum operating conditions, which may be quite different for different aerosols, to be computed. Cigarette smoke was used as a test aerosol to check the experimental and theoretical findings. Although it is shown to be subject to both cloud settling and dense gas subsidence, accurate size classification was obtained. The differential equation describing particle motion in centrifuges has been formulated and solved. Further, techniques of dimensional analysis were applied to the equations modelling flow in centrifuges; results indicate how operating conditions and instrument geometry influence particle size classification. These theoretical studies will lead to the development of improved

  7. Centrifugation after irradiation of red blood cells does not accelerate haemolysis.

    Science.gov (United States)

    Weiss, Dominik R; Goehring, Jasmin; Weisbach, Volker; Strasser, Erwin F; Ringwald, Juergen; Zimmermann, Robert; Eckstein, Reinhold

    2011-01-01

    For intrauterine transfusion and some other rare indications, irradiation and washing or adjustment to an elevated haematocrit is necessary. No data are currently available indicating whether irradiation of red blood cell concentrates (RBCs) might impair the mechanical stability of erythrocytes during centrifugation leading to elevated haemolysis. Consequently, if irradiation and centrifugation of RBCs is necessary, there is no definitive recommendation about the preferred sequence of steps. We divided 20 RBC units that were not older than 9 days into two subunits. These subunits were prepared to yield irradiated RBCs with an elevated haematocrit, as they are used for intrauterine transfusion. One subunit was centrifuged and then irradiated, the other subunit was irradiated and then centrifuged. The units were evaluated in vitro before preparation and on days 1 and 7. We could not find any difference in the haemolysis rate, extracellular LDH or alpha-HBDH between the two groups of RBCs. This observation indicates that centrifugation after irradiation of RBCs does not accelerate haemolysis. A similar ATP content in the two subunits demonstrated no difference in energy metabolism. The extracellular potassium concentration was significantly lower in the subunits washed after irradiation. There is no difference in the haemolysis caused by centrifugation between irradiated and non-irradiated RBCs. However, it is well known that washing RBCs after irradiation significantly lowers the potassium content. Summarising these two findings leads to the conclusion that it is optimal first to irradiate and then to wash RBCs.

  8. Use of short-radius centrifugation to augment ankle-brachial indices.

    Science.gov (United States)

    Grenon, S Marlene; Mateus, Jaime; Hsiang, York; Sidhu, Ravi; Young, Laurence; Gagnon, Joel

    2009-06-01

    Peripheral arterial disease is mainly caused by atherosclerosis and is characterized by decreased circulation, lower blood pressure, and insufficient tissue perfusion in the lower extremities. The hemodynamics of standing and altered gravity environments have been well studied relative to arm blood pressures but are less well understood for ankle pressures. Because regional blood pressure depends, in part, on the gravitational pressure gradient, we hypothesized that artificial gravity exposure on a short-arm centrifuge with the center of rotation above the head would increase blood pressure in the lower extremities. Cardiovascular parameters for 12 healthy subjects were measured during exposure to supine short-arm centrifugation at 20, 25, and 30 revolutions per minute (rpm), corresponding to centripetal accelerations of 0.94, 1.47, and 2.11 Gz at the foot level, respectively. Systolic ankle blood pressure significantly increased at all levels of centrifugation. Ankle-brachial indices (the ratio of systolic ankle to arm blood pressures) increased significantly from 1.17 +/- 0.03 to 1.58 +/- 0.03 at 0.94 Gz (P blood pressure significantly increased at 2.11 Gz, but heart rate did not change significantly. All parameters returned to normal after cessation of centrifugation. We demonstrated that short-radius centrifugation leads to an increase in ankle-brachial indices. This could have potential implications for the treatment of peripheral arterial disease.

  9. 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.

  10. A novel centrifugal separator: conceptual design and analysis of system dynamics

    International Nuclear Information System (INIS)

    Bhardwaj, Utsav

    2016-01-01

    In the processes related to nuclear fuel cycle, we encounter some sort of slurries, like nuclear waste slurries, which need treatment for separation of suspended solids. There are several techniques to accomplish this purpose, like using some chemical action (like that for separation of nuclear fuel ore or for separation of some specific nuclear waste), sedimentation, enhanced sedimentation or forced precipitation using some sort of additives, passage through a specifically designed constricted flow way, centrifugal separation, etc. Centrifugal separation being one of the important techniques used for separation, several centrifugal separators have been designed, developed and being used successfully for a continuously flowing slurry or mixture. The presently designed separator does the process of separation and tries to keep the species once separated isolated uniformly throughout the axial length of the separation region. Some conventional centrifugal separators are non-hermetic too. Here in this paper, a different kind of centrifugal separator has been proposed, which separates the heavier suspended matter as well as the lighter suspended matter from some liquid, that too in bulk in one go. It is very suitable for coarse separation of nuclear ore

  11. Uranium enrichment in Europe by the gas centrifuge process

    International Nuclear Information System (INIS)

    Severin, D.J.E.

    1975-01-01

    To begin with, this lesson gives an outline of the expected energy demand of the Western World and the concentration of the European companies participating in uranium enrichment by the gas centrifuge method. Next, a) the principles of the gas centrifuge method are outlined, b) its advantages over other industrial processes are stressed, and c) the characteristic data of complete plants are given. The existing German, Dutch, and British pilot plants are mentioned as examples for the perfected state of the process. The Capenhurst (UK) and Almedo (NL) demonstration plants, each with a capacity of 200 t SW/a, will have been extended to 2 x 1.000 t SW/a by 1982. Finally, economic data of the gas centrifuge process are given. The term 'separative work' is explained in an annex. (GG) [de

  12. Advances in post-fermented wine clarification by centrifugal technology

    Directory of Open Access Journals (Sweden)

    Giacomo Costagli

    2016-11-01

    Full Text Available Wine clarification processes are deeply determined by complex interaction of wine constituents and application of available technologies as well as use of fining agents. Among others, centrifuge is a consolidated technique applied for many separation duties in the winery. Important advances on improvement of the performance of centrifugal technology have beeen focused on gentle wine treatment, minimal dissolved oxygen and significant reduction of energy consumption helping to dispel old beliefs on a technique considered to be traditional. This paper reviews the development of technology and recent advances on centrifuge improvement and aims to show, through field experimental observation, the importance of removing a portion of particles responsible of haze in the light of very low level of dissolved oxygen and complementarity of alternative recent techniques of wine filtration like cross-flow microfiltration.

  13. Design Optimization of a Centrifugal Fan with Splitter Blades

    Science.gov (United States)

    Heo, Man-Woong; Kim, Jin-Hyuk; Kim, Kwang-Yong

    2015-05-01

    Multi-objective optimization of a centrifugal fan with additionally installed splitter blades was performed to simultaneously maximize the efficiency and pressure rise using three-dimensional Reynolds-averaged Navier-Stokes equations and hybrid multi-objective evolutionary algorithm. Two design variables defining the location of splitter, and the height ratio between inlet and outlet of impeller were selected for the optimization. In addition, the aerodynamic characteristics of the centrifugal fan were investigated with the variation of design variables in the design space. Latin hypercube sampling was used to select the training points, and response surface approximation models were constructed as surrogate models of the objective functions. With the optimization, both the efficiency and pressure rise of the centrifugal fan with splitter blades were improved considerably compared to the reference model.

  14. Centrifugal precipitation chromatography

    Science.gov (United States)

    Ito, Yoichiro; Lin, Qi

    2009-01-01

    Centrifugal precipitation chromatography separates analytes according their solubility in ammonium sulfate (AS) solution and other precipitants. The separation column is made from a pair of long spiral channels partitioned with a semipermeable membrane. In a typical separation, concentrated ammonium sulfate is eluted through one channel while water is eluted through the other channel in the opposite direction. The countercurrent process forms an exponential AS concentration gradient through the water channel. Consequently, protein samples injected into the water channel is subjected to a steadily increasing AS concentration and at the critical AS concentration they are precipitated and deposited in the channel bed by the centrifugal force. Then the chromatographic separation is started by gradually reducing the AS concentration in the AS channel which lowers the AS gradient concentration in the water channel. This results in dissolution of deposited proteins which are again precipitated at an advanced critical point as they move through the channel. Consequently, proteins repeat precipitation and dissolution through a long channel and finally eluted out from the column in the order of their solubility in the AS solution. The present method has been successfully applied to a number of analytes including human serum proteins, recombinant ketosteroid isomerase, carotenoid cleavage enzymes, plasmid DNA, polysaccharide, polymerized pigments, PEG-protein conjugates, etc. The method is capable to single out the target species of proteins by affinity ligand or immunoaffinity separation. PMID:19541553

  15. Spectroscopy of Molecules in Extreme Rotational States Using AN Optical Centrifuge

    Science.gov (United States)

    Mullin, Amy S.; Toro, Carlos; Echibiri, Geraldine; Liu, Qingnan

    2012-06-01

    Our lab has developed a high-power optical centrifuge that is capable of trapping and spinning large number densities of molecules into extreme rotational states. By coupling this device with high resolution transient IR absorption spectroscopy, we measure the time-resolved behavior and energy profiles of individual ro-vibrational states of molecules in very high rotational states. Recent results will be discussed on the spectroscopy of new rotational states, collisional dynamics in the optical centrifuge, spatially-dependent energy profiles and possibilities for new chemistry induced by centrifugal forces.

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

    Science.gov (United States)

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

    2014-06-01

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

  17. Real-Time, Fast Neutron Coincidence Assay of Plutonium With a 4-Channel Multiplexed Analyzer and Organic Scintillators

    Science.gov (United States)

    Joyce, Malcolm J.; Gamage, Kelum A. A.; Aspinall, M. D.; Cave, F. D.; Lavietes, A.

    2014-06-01

    The design, principle of operation and the results of measurements made with a four-channel organic scintillator system are described. The system comprises four detectors and a multiplexed analyzer for the real-time parallel processing of fast neutron events. The function of the real-time, digital multiple-channel pulse-shape discrimination analyzer is described together with the results of laboratory-based measurements with 252Cf, 241Am-Li and plutonium. The analyzer is based on a single-board solution with integrated high-voltage supplies and graphical user interface. It has been developed to meet the requirements of nuclear materials assay of relevance to safeguards and security. Data are presented for the real-time coincidence assay of plutonium in terms of doubles count rate versus mass. This includes an assessment of the limiting mass uncertainty for coincidence assay based on a 100 s measurement period and samples in the range 0-50 g. Measurements of count rate versus order of multiplicity for 252Cf and 241Am-Li and combinations of both are also presented.

  18. The effect of centrifugation speed and time on pre-analytical platelet activation.

    Science.gov (United States)

    Söderström, Anna C; Nybo, Mads; Nielsen, Christian; Vinholt, Pernille J

    2016-12-01

    The results of laboratory analyses are affected by pre-analytical variables, and in particular can platelets be activated by shear handling stress and secrete granular substances. We therefore evaluated the effect of centrifugation speed and time on pre-analytical platelet activation. Citrate- and EDTA-anticoagulated blood from healthy volunteers were centrifuged at 80-10,000 g for 5-15 min to prepare plasma and platelet-rich plasma. Pre-analytical platelet activation was assessed by flow cytometric measurement of platelet P-selectin (CD62p) expression. Blood cell counts, mean platelet volume (MPV), immature platelet fraction (IPF), and platelet distribution width (PDW) were measured. Platelet aggregation in platelet-rich plasma induced by arachidonic acid (AA), ADP or thrombin receptor activator peptide-6 (TRAP) was tested by 96-well aggregometry. The median percentage of platelets expressing P-selectin in citrate- and EDTA-plasma centrifuged at 2000 g for 10 min were 43% [interquartile range (IQR), 38%-53%] and 56% (IQR, 31%-78%), respectively (p=0.82). Platelet-rich plasma prepared at 100-250 g for 10 min had significantly lower platelet P-selectin expression (11%-15%), pcentrifuged. In platelet-rich plasma, increasing centrifugation speed significantly increased platelet yield but decreased contamination from other blood cells, platelet composition was altered as platelet parameters (MPV, IPF, and PDW) was lowered. Platelet aggregation was not affected by the centrifugation speed platelet-rich plasma was prepared. Proportional to centrifugation speed, platelets in plasma and platelet-rich plasma were activated with centrifugation speed, cell content and composition changed while platelet aggregation was unaltered.

  19. Effects of different centrifugation conditions on clinical chemistry and Immunology test results.

    Science.gov (United States)

    Minder, Elisabeth I; Schibli, Adrian; Mahrer, Dagmar; Nesic, Predrag; Plüer, Kathrin

    2011-05-10

    The effect of centrifugation time of heparinized blood samples on clinical chemistry and immunology results has rarely been studied. WHO guideline proposed a 15 min centrifugation time without citing any scientific publications. The centrifugation time has a considerable impact on the turn-around-time. We investigated 74 parameters in samples from 44 patients on a Roche Cobas 6000 system, to see whether there was a statistical significant difference in the test results among specimens centrifuged at 2180 g for 15 min, at 2180 g for 10 min or at 1870 g for 7 min, respectively. Two tubes with different plasma separators (both Greiner Bio-One) were used for each centrifugation condition. Statistical comparisons were made by Deming fit. Tubes with different separators showed identical results in all parameters. Likewise, excellent correlations were found among tubes to which different centrifugation conditions were applied. Fifty percent of the slopes lay between 0.99 and 1.01. Only 3.6 percent of the statistical tests results fell outside the significance level of p < 0.05, which was less than the expected 5%. This suggests that the outliers are the result of random variation and the large number of statistical tests performed. Further, we found that our data are sufficient not to miss a biased test (beta error) with a probability of 0.10 to 0.05 in most parameters. A centrifugation time of either 7 or 10 min provided identical test results compared to the time of 15 min as proposed by WHO under the conditions used in our study.

  20. Experimental Study on Noise Characteristic of Centrifugal Compressor Surge

    OpenAIRE

    Yang, Qichao; Zhao, Yuanyang; SHU, Yue; LI, Xiaosa; LI, Liansheng

    2016-01-01

    The centrifugal air compressor test rig is was designed and established. The experimental study was carried out on the surge characteristics of centrifugal compressor including the pressure in the pipe and the noise characteristics under different rotation speed. The tested results showed that both the suction pressure and discharge pressure fluctuation increase under surge condition and the amplitude of discharge pressure fluctuation is significantly higher than that of suction pressure. In ...

  1. Centrifuges for Microgravity Simulation. The Reduced Gravity Paradigm

    International Nuclear Information System (INIS)

    Loon, Jack J. W. A. van

    2016-01-01

    Due to the cumbersome nature of performing real microgravity—spaceflight research scientists have been searching for alternatives to perform simulated microgravity or partial gravity experiments on Earth. For more than a century one uses the slow rotating clinostat as developed by von Sachs at the end of the nineteenth century. Since then, the fast rotating clinostat, the 3D clinostat or the random positioning machine, the rotating wall vessels, tail suspension and bed rest head down tilt and lately the levitating magnets have been introduced. Several of these simulation systems provide some similarities of the responses and phenotypes as seen in real microgravity experiments. However, one should always realize that we cannot reduce gravity on Earth, other than the relative short duration free fall studies in e.g., drop towers or parabolic aircraft. In this paper we want to explore the possibility to apply centrifuges to simulate microgravity or maybe better to simulate hypo-gravity. This Reduced Gravity Paradigm, RGP is based on the premise that adaptations seen going from a hypergravity level to a lower gravity are similar as changes seen going from unit gravity to microgravity.

  2. Centrifuges for Microgravity Simulation. The Reduced Gravity Paradigm

    Energy Technology Data Exchange (ETDEWEB)

    Loon, Jack J. W. A. van, E-mail: j.vanloon@vumc.nl [Department of Oral and Maxillofacial Surgery / Oral Pathology, Dutch Experiment Support Center, VU University Medical Center and Academic Centre for Dentistry Amsterdam, Amsterdam (Netherlands); TEC-MMG LIS Lab, European Space Agency Technology Center, Noordwijk (Netherlands)

    2016-07-19

    Due to the cumbersome nature of performing real microgravity—spaceflight research scientists have been searching for alternatives to perform simulated microgravity or partial gravity experiments on Earth. For more than a century one uses the slow rotating clinostat as developed by von Sachs at the end of the nineteenth century. Since then, the fast rotating clinostat, the 3D clinostat or the random positioning machine, the rotating wall vessels, tail suspension and bed rest head down tilt and lately the levitating magnets have been introduced. Several of these simulation systems provide some similarities of the responses and phenotypes as seen in real microgravity experiments. However, one should always realize that we cannot reduce gravity on Earth, other than the relative short duration free fall studies in e.g., drop towers or parabolic aircraft. In this paper we want to explore the possibility to apply centrifuges to simulate microgravity or maybe better to simulate hypo-gravity. This Reduced Gravity Paradigm, RGP is based on the premise that adaptations seen going from a hypergravity level to a lower gravity are similar as changes seen going from unit gravity to microgravity.

  3. Basic characteristics of centrifuges, (4)

    International Nuclear Information System (INIS)

    Kai, Tsunetoshi

    1977-01-01

    A method of numerically solving the convection-diffusion equation is presented for a binary isotopic gas mixture in the axisymmetric velocity field. A modified Newton's method is employed to perform the numerical integration without the assumptions that the pressure can be estimated from the rigid rotation model and the temperature of gas is uniform. A suitable form of the finite difference equation gives a computationally stable integration with reasonable representation of the molar concentration distribution of isotopic molecules in a rotating cylinder. The method includes a Gaussian elimination procedure which consists of the transformation of the Jacobian matrix to a triangular matrix followed by the backward elimination. Computations are made on UF 6 gas in various centrifuges which have the openings for feed, product and waste on the end plates. Discussions are also presented on gas flows and separative efficiencies for the centrifuges which have baffle plates, skirting plates and bellows. (auth.)

  4. Effect on Vehicle Turbocharger Exhaust Gas Energy Utilization for the Performance of Centrifugal Compressors under Plateau Conditions

    Directory of Open Access Journals (Sweden)

    Hong Zhang

    2017-12-01

    Full Text Available This paper is focused on the performance of centrifugal compressors for vehicle turbochargers operating at high altitude. The reasons for turbocharged diesel engine power loss increases and bad economy performance caused by exhaust gas energy utilization are investigated. The atmosphere’s impact on the turbocharger centrifugal compressor’s energy distribution characteristics under the plateau is discussed. The key parameters that affect compressor characteristics are concluded in a theoretical method. A simulation calculation model is established to accurately predict compressor performance at high altitude. By comparing the experimental results, the calculation results are validated. The details of the internal flow fields analysis, including critical parameters of a compressor operating at high altitude, are analyzed. The results show that with the increase of altitude from 0 m to 4500 m, the peak efficiency of the compressor is reduced by 2.4%, while the peak pressure ratio is increased by 7%. The main influence characters of the plateau environment on the turbocharger centrifugal compressor performance, such as blade loads, exergy utilization and entropy distribution are concluded. The key factors for compressor performance and compressor energy flow control design method operated at high altitude are obtained.

  5. Model tests of geosynthetic reinforced slopes in a geotechnical centrifuge

    International Nuclear Information System (INIS)

    Aklik, P.

    2012-01-01

    Geosynthetic-reinforced slopes and walls became very popular in recent years because of their financial, technical, and ecological advantages. Centrifuge modelling is a powerful tool for physical modelling of reinforced slopes and offers the advantage to observe the failure mechanisms of the slopes. In order to replicate the gravity induced stresses of a prototype structure in a geometrically 1/N reduced model, it is necessary to test the model in a gravitational field N times larger than that of the prototype structure. In this dissertation, geotextile-reinforced slope models were tested in a geotechnical centrifuge to identify the possible failure mechanisms. Slope models were tested by varying slope inclination, tensile strengths of the geotextiles, and overlapping lengths. Photographs of the geotextile reinforced slope models in flight were taken with a digital camera and the soil deformations of geotextile reinforced slopes were evaluated with Particle Image Velocimetry (PIV). The experimental results showed that failure of the centrifuge models initiated at midheight of the slope, and occurred due to geotextile breakage instead of pullout. The location of the shear surface is independent of the tensile strength of the geotextile; it is dependent on the shear strength of the soil. It is logical to see that the required acceleration of the centrifuge at slope failure was decreased with increasing slope inclination. An important contribution to the stability of the slope models was provided by the overlapping of the geotextile layers. It has a secondary reinforcement effect when it was prolonged and passed through the shear surface. Moreover, the location of the shear surface observed with PIV analysis exactly matches the tears of the retrieved geotextiles measured carefully after the centrifuge testing. It is concluded that PIV is an efficient tool to instrument the slope failures in a geotechnical centrifuge.(author) [de

  6. Effect of centrifugation and washing on adipose graft viability: a new method to improve graft efficiency.

    Science.gov (United States)

    Hoareau, Laurence; Bencharif, Karima; Girard, Anne-Claire; Gence, Lydie; Delarue, Pierre; Hulard, Olivier; Festy, Franck; Roche, Regis

    2013-05-01

    Adipose tissue grafting is a promising method in the field of surgical filling. We studied the effect of centrifugation on fat grafts, and we propose an optimised protocol for the improvement of adipose tissue viability. Adipose tissue was subjected to different centrifugations, and the volumes of interstitial liquid and oil released were measured to choose the optimal condition. Tissue from this condition was then compared to tissue obtained from two traditional techniques: strong centrifugation (commonly 3 min at 3000 rpm/900 g), and decantation, by injecting into immunodeficient mice. The cytokine interleukin-6 (IL-6) and chemokine monocyte chemotactic protein-1 (MCP-1) were assayed 24 h post-injection, and after 1 month of grafting the state of the lipografts was evaluated through macroscopic and histological analysis, with oil gap area measurement. Strong centrifugation (900 g, 1800 g) is deleterious for adipose tissue because it leads to until threefold more adipocyte death compared to low centrifugation (100 g, 400 g). In addition, mice injected with strong centrifuged and non-centrifuged adipose tissue have higher rates of blood IL-6 and MCP-1, compared to those grafted with soft centrifuged fat. Moreover, extensive lipid vacuoles were detectable on histological sections of the non-centrifuged lipografts, whereas lipografts from soft centrifugation contain a higher amount of connective tissue containing collagen fibres. It is necessary to wash and centrifuge adipose tissue before reinjection in order to remove infiltration liquid and associated toxic molecules, which in the long term are deleterious for the graft. However, strong centrifugation is not recommended since it leads very quickly to greater adipocyte death. Thus, soft centrifugation (400 g/1 min), preceded by washings, seems to be the most appropriate protocol for the reinjection of adipose tissue. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published

  7. J-Specific Dynamics in AN Optical Centrifuge Using Transient IR Spectroscopy

    Science.gov (United States)

    Murray, Matthew J.; Liu, Qingnan; Toro, Carlos; Mullin, Amy S.

    2013-06-01

    Quantum state-specific dynamics are reported for a number of CO_{2} rotational states in an optical centrifuge. The optical centrifuge results from combining oppositely-chirped ultrafast laser pulses and spinning CO_{2} molecules into extremely high rotational states with J≈220. Collisions of centrifuged molecules induce depletion of population from low-J states (J=0 and 36) and lead to appearance of population in high J states (J=36, 54 and 76). Transient Doppler-broadened line profiles for individual CO_{2} states reveal that the depletion populations have narrow velocity distributions with translational temperatures significantly colder than 300 K. Molecules that appear in the higher rotational states have broad velocity distributions, showing that both rotational and translational energy are imparted in collisions of the centrifuged molecules. These results show that substantial amounts of angular momentum persist after many collisions and that translational energy exchange continues for several thousand collisions.

  8. A wireless centrifuge force microscope (CFM) enables multiplexed single-molecule experiments in a commercial centrifuge.

    Science.gov (United States)

    Hoang, Tony; Patel, Dhruv S; Halvorsen, Ken

    2016-08-01

    The centrifuge force microscope (CFM) was recently introduced as a platform for massively parallel single-molecule manipulation and analysis. Here we developed a low-cost and self-contained CFM module that works directly within a commercial centrifuge, greatly improving accessibility and ease of use. Our instrument incorporates research grade video microscopy, a power source, a computer, and wireless transmission capability to simultaneously monitor many individually tethered microspheres. We validated the instrument by performing single-molecule force shearing of short DNA duplexes. For a 7 bp duplex, we observed over 1000 dissociation events due to force dependent shearing from 2 pN to 12 pN with dissociation times in the range of 10-100 s. We extended the measurement to a 10 bp duplex, applying a 12 pN force clamp and directly observing single-molecule dissociation over an 85 min experiment. Our new CFM module facilitates simple and inexpensive experiments that dramatically improve access to single-molecule analysis.

  9. Container for centrifuging blood

    International Nuclear Information System (INIS)

    Narra, R.K.

    1982-01-01

    A container is described for use in drawing patient's blood, centrifuging the blood and then labelling the separated red cells with sup(99m)Tc. It consists of a tube with a central chamber and a lower portion provided with an aperture in which a weir is supported and extends into the central chamber. The weir has a central channel. A resilient plug seals the aperture. (author)

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

    International Nuclear Information System (INIS)

    Kaperonis, A.A.; Chien, S.

    1989-01-01

    Plasma 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 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

  11. CFD Ventilation Study for the Human Powered Centrifuge at the International Space Station

    Science.gov (United States)

    Son, Chang H.

    2011-01-01

    The Human Powered Centrifuge (HPC) is a hyper gravity facility that will be installed on board the International Space Station (ISS) to enable crew exercises under the artificial gravity conditions. The HPC equipment includes a bicycle for long-term exercises of a crewmember that provides power for rotation of HPC at a speed of 30 rpm. The crewmember exercising vigorously on the centrifuge generates the amount of carbon dioxide of several times higher than a crewmember in ordinary conditions. The goal of the study is to analyze the airflow and carbon dioxide distribution within Pressurized Multipurpose Module (PMM) cabin. The 3D computational model included PMM cabin. The full unsteady formulation was used for airflow and CO2 transport modeling with the so-called sliding mesh concept is considered in the rotating reference frame while the rest of the cabin volume is considered in the stationary reference frame. The localized effects of carbon dioxide dispersion are examined. Strong influence of the rotating HPC equipment on the CO2 distribution is detected and discussed.

  12. Xylem vulnerability to cavitation can be accurately characterised in species with long vessels using a centrifuge method.

    Science.gov (United States)

    Tobin, M F; Pratt, R B; Jacobsen, A L; De Guzman, M E

    2013-05-01

    Vulnerability to cavitation curves describe the decrease in xylem hydraulic conductivity as xylem pressure declines. Several techniques for constructing vulnerability curves use centrifugal force to induce negative xylem pressure in stem or root segments. Centrifuge vulnerability curves constructed for long-vesselled species have been hypothesised to overestimate xylem vulnerability to cavitation due to increased vulnerability of vessels cut open at stem ends that extend to the middle or entirely through segments. We tested two key predictions of this hypothesis: (i) centrifugation induces greater embolism than dehydration in long-vesselled species, and (ii) the proportion of open vessels changes centrifuge vulnerability curves. Centrifuge and dehydration vulnerability curves were compared for a long- and short-vesselled species. The effect of open vessels was tested in four species by comparing centrifuge vulnerability curves for stems of two lengths. Centrifuge and dehydration vulnerability curves agreed well for the long- and short-vesselled species. Centrifuge vulnerability curves constructed using two stem lengths were similar. Also, the distribution of embolism along the length of centrifuged stems matched the theoretical pressure profile induced by centrifugation. We conclude that vulnerability to cavitation can be accurately characterised with vulnerability curves constructed using a centrifuge technique, even in long-vesselled species. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

  13. NECESSARY CONDITIONS OF STABILITY MOVING PARTS OF ROTOR CENTRIFUGE

    OpenAIRE

    Strackeljan, Jens; Babenko, Andriy; Lavrenko, Iaroslav

    2014-01-01

    Design features of modern centrifuges studied. Revealed that their rotors are movable elements that revolve around horizontal axes. The dynamics of these moving parts of laboratory centrifuge considered. Using the Lagrange equation of the second kind the resulting differential equations of their motion considered. The modeling visualization of motion using the software package RecurDyn was made. The results that obtained by the research package RecurDyn and analytically showed that their moti...

  14. Performance and internal flow condition of mini centrifugal pump with splitter blades

    International Nuclear Information System (INIS)

    Shigemitsu, T; Fukutomi, J; Kaji, K; Wada, T

    2012-01-01

    Mini centrifugal pumps having a diameter smaller than 100mm are employed in many fields. But the design method for the mini centrifugal pump is not established because the internal flow condition for these small-sized fluid machines is not clarified and conventional theory is not suitable for small-sized pumps. Therefore, mini centrifugal pumps with simple structure were investigated by this research. Splitter blades were adopted in this research to improve the performance and the internal flow condition of mini centrifugal pump which had large blade outlet angle. The original impeller without the splitter blades and the impeller with the splitter blades were prepared for an experiment. The performance tests are conducted with these rotors in order to investigate the effect of the splitter blades on performance and internal flow condition of mini centrifugal pump. On the other hand, a three dimensional steady numerical flow analysis is conducted with the commercial code (ANSYS-CFX) to investigate the internal flow condition in detail. It is clarified from the experimental results that the performance of the mini centrifugal pump is improved by the effect of the splitter blades. The blade-to-blade low velocity regions are suppressed in the case with the splitter blades and the total pressure loss regions are decreased. The effects of the splitter blades on the performance and the internal flow condition are discussed in this paper.

  15. Applicability of eddy viscosity turbulence models in low specific speed centrifugal pump

    International Nuclear Information System (INIS)

    Wang, Y; Wang, W J

    2012-01-01

    The accuracy of numerical simulation determines the performance prediction whether to be successful or not in the research of centrifugal pump. In order to study the applicability of different turbulence models in the low specific speed centrifugal pump, the object was based on XST45-200 stamping and welding centrifugal pump. Five different kinds of standards which are k-ε model, RNG k-ε model, Realizable k-ε model, Standard k-ω model and SST k-ω model are adopted in steady numerical simulations of the centrifugal pump flow fields. Then, inner and outside characteristics of the centrifugal pump were gotten .And it also provides the calculation of pressure distribution using different turbulence models in the five conditions. Lastly, the performance curves of head, power and efficiency are compared with the test. The results show a good agreement between five kinds of turbulence models and tests obtained in small flow and design condition. In large flow, the standard k-ε model is worse than the other four, which is larger than the tested head with a relative deviation of 47.9% and efficiency with 50%.The calculation accuracy which used RNG k-ε model is highest. SST k-ω model takes the second place. Standard k-ω model can be used for the numerical simulation in the low specific speed centrifugal pump.

  16. 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.

  17. Simulation of performance of centrifugal circulators with vaneless diffuser for GCR applications

    International Nuclear Information System (INIS)

    Tauveron, N.; Dor, I.

    2010-01-01

    In the frame of the international forum GenIV, CEA has selected various innovative concepts of gas-cooled nuclear reactor. Thermal hydraulic performances are a key issue for the design. For transient conditions and decay heat removal situations, the thermal hydraulic performance must remain as high as possible. In this context, all the transient situations, the incidental and accidental scenarii must be evaluated by a validated system code able to correctly describe, in particular, the thermal hydraulics of the whole plant. As concepts use a helium compressor to maintain the flow in the core, a special emphasis must be laid on compressor modelling. Centrifugal circulators with a vaneless diffuser have significant properties in term of simplicity, cost, ability to operate over a wide range of conditions. The objective of this paper is to present a dedicated description of centrifugal compressor, based on a one-dimensional approach. This type of model requires various correlations as input data. The present contribution consists in establishing and validating the numerical simulations (including different sets of correlations) by comparison with representative experimental data. The results obtained show a qualitatively correct behaviour of the model compared to open literature cases of the gas turbine aircraft community and helium circulators of high temperature gas reactors. The model is finally used in a depressurised transient simulation of a small power gas fast reactor (ALLEGRO concept). Advantages of this model versus first preliminary simulations are shown. Further work on modelling and validation are nevertheless needed to have a better confidence in the simulation predictions.

  18. Simulation of performance of centrifugal circulators with vaneless diffuser for GCR applications

    Energy Technology Data Exchange (ETDEWEB)

    Tauveron, N., E-mail: nicolas.tauveron@cea.f [CEA, DEN, DER/SSTH, 17 rue des Martyrs, F-38054 Grenoble (France); Dor, I., E-mail: isabelle.dor@cea.f [CEA, DEN, DER/SSTH, 17 rue des Martyrs, F-38054 Grenoble (France)

    2010-10-15

    In the frame of the international forum GenIV, CEA has selected various innovative concepts of gas-cooled nuclear reactor. Thermal hydraulic performances are a key issue for the design. For transient conditions and decay heat removal situations, the thermal hydraulic performance must remain as high as possible. In this context, all the transient situations, the incidental and accidental scenarii must be evaluated by a validated system code able to correctly describe, in particular, the thermal hydraulics of the whole plant. As concepts use a helium compressor to maintain the flow in the core, a special emphasis must be laid on compressor modelling. Centrifugal circulators with a vaneless diffuser have significant properties in term of simplicity, cost, ability to operate over a wide range of conditions. The objective of this paper is to present a dedicated description of centrifugal compressor, based on a one-dimensional approach. This type of model requires various correlations as input data. The present contribution consists in establishing and validating the numerical simulations (including different sets of correlations) by comparison with representative experimental data. The results obtained show a qualitatively correct behaviour of the model compared to open literature cases of the gas turbine aircraft community and helium circulators of high temperature gas reactors. The model is finally used in a depressurised transient simulation of a small power gas fast reactor (ALLEGRO concept). Advantages of this model versus first preliminary simulations are shown. Further work on modelling and validation are nevertheless needed to have a better confidence in the simulation predictions.

  19. Reflection of centrifugal pumps maintenance

    International Nuclear Information System (INIS)

    Mozos Fernandez, V.

    2010-01-01

    The aim of this work is to prove that is not necessary a deep and complex knowledge to manage the centrifugal pumps maintenance. According to the author, only deep but single technical knowledge about causes of breakdowns in the different and simple component parts of the pumps, are required. (Author)

  20. Analytical performance of centrifuge-based device for clinical chemistry testing.

    Science.gov (United States)

    Suk-Anake, Jamikorn; Promptmas, Chamras

    2012-01-01

    A centrifuge-based device has been introduced to the Samsung Blood Analyzer (SBA). The verification of this analyzer is essential to meet the ISO15189 standard. Analytical performance was evaluated according to the NCCLS EP05-A method. The results of plasma samples were compared between the SBA and a Hitachi 917 analyzer according to the NCCLS EP09-A2-IR method. Percent recovery was determined via analysis of original control serum and spiked serum. Within-run precision was found to be 0.00 - 6.61% and 0.96 - 5.99% in normal- and abnormal-level assays, respectively, while between-run precision was 1.31 - 9.09% and 0.89 - 6.92%, respectively. The correlation coefficients (r) were > 0.990. The SBA presented analytical accuracy at 96.64 +/- 3.39% to 102.82 +/- 2.75% and 98.31 +/- 4.04% to 103.61 +/- 8.28% recovery, respectively. The results obtained verify that all of the 13 tests performed using the SBA demonstrates good and reliable precision suitable for use in qualified clinical chemistry laboratory service.

  1. FAST: FAST Analysis of Sequences Toolbox

    Directory of Open Access Journals (Sweden)

    Travis J. Lawrence

    2015-05-01

    Full Text Available FAST (FAST Analysis of Sequences Toolbox provides simple, powerful open source command-line tools to filter, transform, annotate and analyze biological sequence data. Modeled after the GNU (GNU’s Not Unix Textutils such as grep, cut, and tr, FAST tools such as fasgrep, fascut, and fastr make it easy to rapidly prototype expressive bioinformatic workflows in a compact and generic command vocabulary. Compact combinatorial encoding of data workflows with FAST commands can simplify the documentation and reproducibility of bioinformatic protocols, supporting better transparency in biological data science. Interface self-consistency and conformity with conventions of GNU, Matlab, Perl, BioPerl, R and GenBank help make FAST easy and rewarding to learn. FAST automates numerical, taxonomic, and text-based sorting, selection and transformation of sequence records and alignment sites based on content, index ranges, descriptive tags, annotated features, and in-line calculated analytics, including composition and codon usage. Automated content- and feature-based extraction of sites and support for molecular population genetic statistics makes FAST useful for molecular evolutionary analysis. FAST is portable, easy to install and secure thanks to the relative maturity of its Perl and BioPerl foundations, with stable releases posted to CPAN. Development as well as a publicly accessible Cookbook and Wiki are available on the FAST GitHub repository at https://github.com/tlawrence3/FAST. The default data exchange format in FAST is Multi-FastA (specifically, a restriction of BioPerl FastA format. Sanger and Illumina 1.8+ FastQ formatted files are also supported. FAST makes it easier for non-programmer biologists to interactively investigate and control biological data at the speed of thought.

  2. Digital dynamic amplitude-frequency spectra analyzer

    International Nuclear Information System (INIS)

    Kalinnikov, V.A.; )

    2006-01-01

    The spectra analyzer is intended for the dynamic spectral analysis of signals physical installations and noise filtering. The recurrence Fourier transformation algorithm is used in the digital dynamic analyzer. It is realized on the basis of the fast logic FPGA matrix and the special signal ADSP microprocessor. The discretization frequency is 2 kHz-10 MHz. The number of calculated spectral coefficients is not less 512. The functional fast-action is 20 ns [ru

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

    Directory of Open Access Journals (Sweden)

    H. Nakajima

    2006-01-01

    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 water pressure were measured during the tests at multiple gravity levels. Based on the scaling laws 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 40g, the optimized unsaturated parameters compared well when accurate pore water pressure measurements were included along with cumulative outflow as input data. With its capability to implement variety of instrumentations under well controlled initial and boundary conditions and to shorten testing time, the centrifuge modeling technique is attractive as an alternative experimental method that provides more freedom to set inverse problem conditions for the parameter estimation.

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

    Science.gov (United States)

    Nakajima, H.; Stadler, A. T.

    2006-10-01

    Centrifuge modeling of one-step outflow tests were carried out using a 2-m radius geotechnical centrifuge, and the cumulative outflow and transient pore water pressure were measured during the tests at multiple gravity levels. Based on the scaling laws 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 40g, the optimized unsaturated parameters compared well when accurate pore water pressure measurements were included along with cumulative outflow as input data. With its capability to implement variety of instrumentations under well controlled initial and boundary conditions and to shorten testing time, the centrifuge modeling technique is attractive as an alternative experimental method that provides more freedom to set inverse problem conditions for the parameter estimation.

  5. Centrifugal compressor fault diagnosis based on qualitative simulation and thermal parameters

    Science.gov (United States)

    Lu, Yunsong; Wang, Fuli; Jia, Mingxing; Qi, Yuanchen

    2016-12-01

    This paper concerns fault diagnosis of centrifugal compressor based on thermal parameters. An improved qualitative simulation (QSIM) based fault diagnosis method is proposed to diagnose the faults of centrifugal compressor in a gas-steam combined-cycle power plant (CCPP). The qualitative models under normal and two faulty conditions have been built through the analysis of the principle of centrifugal compressor. To solve the problem of qualitative description of the observations of system variables, a qualitative trend extraction algorithm is applied to extract the trends of the observations. For qualitative states matching, a sliding window based matching strategy which consists of variables operating ranges constraints and qualitative constraints is proposed. The matching results are used to determine which QSIM model is more consistent with the running state of system. The correct diagnosis of two typical faults: seal leakage and valve stuck in the centrifugal compressor has validated the targeted performance of the proposed method, showing the advantages of fault roots containing in thermal parameters.

  6. Massively Parallel Single-Molecule Manipulation Using Centrifugal Force

    Science.gov (United States)

    Wong, Wesley; Halvorsen, Ken

    2011-03-01

    Precise manipulation of single molecules has led to remarkable insights in physics, chemistry, biology, and medicine. However, two issues that have impeded the widespread adoption of these techniques are equipment cost and the laborious nature of making measurements one molecule at a time. To meet these challenges, we have developed an approach that enables massively parallel single- molecule force measurements using centrifugal force. This approach is realized in the centrifuge force microscope, an instrument 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. Currently, we are taking steps to integrate high-resolution detection, fluorescence, temperature control and a greater dynamic range in force. With significant benefits in efficiency, cost, simplicity, and versatility, single-molecule centrifugation has the potential to expand single-molecule experimentation to a wider range of researchers and experimental systems.

  7. Centrifuge: rapid and sensitive classification of metagenomic sequences.

    Science.gov (United States)

    Kim, Daehwan; Song, Li; Breitwieser, Florian P; Salzberg, Steven L

    2016-12-01

    Centrifuge is a novel microbial classification engine that enables rapid, accurate, and sensitive labeling of reads and quantification of species on desktop computers. The system uses an indexing scheme based on the Burrows-Wheeler transform (BWT) and the Ferragina-Manzini (FM) index, optimized specifically for the metagenomic classification problem. Centrifuge requires a relatively small index (4.2 GB for 4078 bacterial and 200 archaeal genomes) and classifies sequences at very high speed, allowing it to process the millions of reads from a typical high-throughput DNA sequencing run within a few minutes. Together, these advances enable timely and accurate analysis of large metagenomics data sets on conventional desktop computers. Because of its space-optimized indexing schemes, Centrifuge also makes it possible to index the entire NCBI nonredundant nucleotide sequence database (a total of 109 billion bases) with an index size of 69 GB, in contrast to k-mer-based indexing schemes, which require far more extensive space. © 2016 Kim et al.; Published by Cold Spring Harbor Laboratory Press.

  8. Centrifugal vacuum casting for fuel cladding tube blanks

    International Nuclear Information System (INIS)

    Zelenskii, V.F.; Neklyudov, I.M.; Chernyi, B.P.; Zeidlits, M.P.; Vanzha, A.F.; Rubashko, V.G.; Ryabchikov, L.N.; Smirnov, Y.K.; Bespalova, V.R.; Mashkarova, V.T.; Rybal'chenko, N.D.

    1990-01-01

    An advanced technique for making tube blanks with an acceptable level of nonmetallic inclusions is vacuum induction melting combined with centrifugal casting, as the latter gives a cylindrical casting having an axial hole, while the cast metal has elevated density and contains fewer nonmetallic inclusions than does the metal cast in a stationary mold. The reduction in the nonmetallic inclusions occurs because of increased rates of floating up in the rotating mold on account of the centrifugal force and the rejection to the inner surface. One can choose the parameters such as the pouring speed, rotational speed, mold cooling, and liquid-metal temperature and can introduce a deoxidizer to remove the nonmetallic inclusions or reduce the grain size of them and produce an appropriate cast structure and obtain a metal whose quality is the same as that on vacuum induction melting with secondary arc remelting. For these purposes, the authors have developed centrifugal-casting machines for use under vacuum or in inert gases with horizontal and vertical mold rotation axes

  9. Development and optimization of a new processing approach for manufacturing topical liposomes-in-hydrogel drug formulations by dual asymmetric centrifugation.

    Science.gov (United States)

    Ingebrigtsen, Sveinung G; Škalko-Basnet, Nataša; Holsæter, Ann Mari

    2016-09-01

    The objective of the present study was to utilize dual asymmetric centrifugation (DAC) as a novel processing approach for the production of liposomes-in-hydrogel formulations. Lipid films of phosphatidylcholine, with and without chloramphenicol (CAM), were hydrated and homogenized by DAC to produce liposomes in the form of vesicular phospholipid gels with a diameter in the size range of 200-300 nm suitable for drug delivery to the skin. Different homogenization processing parameters were investigated along with the effect of adding propylene glycol (PG) to the formulations prior to homogenization. The produced liposomes were incorporated into a hydrogel made of 2.5% (v/v) soluble β-1,3/1,6-glucan (SBG) and mixed by DAC to achieve a homogenous liposomes-in-hydrogel-formulation suitable for topical application. CAM-containing liposomes with a vesicle diameter of 282 ± 30 nm and polydispersity index (PI) of 0.13 ± 0.02 were successfully produced by DAC after 50 min centrifugation at 3500 rpm, and homogenously (< 4% content variation) incorporated into the SBG hydrogel. Addition of PG decreased the necessary centrifugation time to 2 min and 55 s, producing liposomes of 230 ± 51 nm and PI of 0.25 ± 0.04. All formulations had an entrapment efficiency of approximately 50%. We managed to develop a relatively fast and reproducible new method for the production of liposomes-in-hydrogel formulations by DAC.

  10. Centrifugal gas separator

    Energy Technology Data Exchange (ETDEWEB)

    Kanagawa, A; Fujii, O; Nakamoto, H

    1970-03-09

    Counter currents in the rotary drum of a centrifugal gas separator are produced by providing, at either end of the drum in the vicinity of the circumferential and central positions, respectively, outflow and inflow holes with a communicating passage external to the drum there between whereby gaseous counter currents are caused to flow within the drum and travel through the passage which is provided with gas flow adjustment means. Furthermore, the space defined by the stationary portion of the passage and the rotor drum is additionally provided with a screw pump or throttling device at either its stationary side or drum side or both in order to produce a radially directed gas flow therewithin. A gas mixture is axially admitted into the drum while centrifugal force and a cooling element provided therebelow cause an increase in gas pressure along and a gaseous flow toward the wall member, whereupon the comparatively high pressured circumferentially distributed gas is extracted from the outlet holes, flows through the external gas passage and back into the lower pressured drum core through the inlet holes, thus producing the desired counter currents. The gases thus separated are withdrawn along axially provided discharge pipes. Accordingly, this invention permits heating elements which were formerly used to produce thermal convection currents to be disposed of and allows the length of the rotor drum to be more efficiently utilized to enhance separation efficiency.

  11. Spin doctors: new innovations for centrifugal apheresis.

    Science.gov (United States)

    Kambic, H E; Nosé, Y

    1997-08-01

    The preparation of plasma from blood has a long history dating back to the early 1900s when the concept of blood washing replaced the traditional blood letting. Over the next 57 years landmark discoveries such as centrifugal and membrane filtration systems led to different and rapid plasma, solute, and cell separation. These were not singular events but rather events influenced by the converging chemical, physiological, and engineering advances that have characterized the latter half of the 20th century. These events have led to entire new fields of biomedical research. The biotechnology for on-line plasma separation and plasma treatment has opened a new era, expanding the application of extracorporeal technology to modern therapeutic medicine. The association of biochemical or cellular abnormalities with various disease states provides the rationale for therapeutic plasma exchange (the removal of large amounts of patient's plasma, alone or with replacement with crystalloid) and therapeutic cytopheresis (removal of cellular elements). The purpose of this review is to provide a historical picture of the innovative ideas of the spin doctors and their devices, which predate the centrifugal blood and cell separators commonplace to any hospital or blood bank worldwide. The emphasis is to define the historical events and their impacts on the development of centrifugal devices and apheresis technologies.

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

    International Nuclear Information System (INIS)

    Queiroz, Paulo Cesar Beltrao de; Zouain, Desiree Moraes

    2009-01-01

    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)

  13. Impeller inlet geometry effect on performance improvement for centrifugal pumps

    International Nuclear Information System (INIS)

    Luo, Xianwu; Zhang, Yao; Peng, Junqi; Xu, Hongyuan; Yu, Weiping

    2008-01-01

    This research treats the effect of impeller inlet geometry on performance improvement for a boiler feed pump, who is a centrifugal pump having specific speed of 183 m.m 3 min -1 .min -1 and close type impeller with exit diameter of 450 mm. The hydraulic performance and cavitation performance of the pump have been tested experimentally. In order to improve the pump, five impellers have been considered by extending the blade leading edge or applying much larger blade angle at impeller inlet compared with the original impeller. The 3-D turbulent flow inside those pumps has been analyzed basing on RNG k-ε turbulence model and VOF cavitation model. It is noted that the numerical results are fairly good compared with the experiments. Based on the experimental test and numerical simulation, the following conclusions can be drawn: (1) Impeller inlet geometry has important influence on performance improvement in the case of centrifugal pump. Favorite effects on performance improvement have been achieved by both extending the blade leading edge and applying much larger blade angle at impeller inlet: (2) It is suspected that the extended leading edge have favorite effect for improving hydraulic performance, and the much larger blade angle at impeller inlet have favorite effect for improving cavitation performance for the test pump: (3) Uniform flow upstream of impeller inlet is helpful for improving cavitation performance of the pump

  14. Protein removal from waste brines generated during ham salting through acidification and centrifugation.

    Science.gov (United States)

    Gutiérrez-Martínez, Maria del Rosario; Muñoz-Guerrero, Hernán; Alcaína-Miranda, Maria Isabel; Barat, José Manuel

    2014-03-01

    The salting step in food processes implies the production of large quantities of waste brines, having high organic load, high conductivity, and other pollutants with high oxygen demand. Direct disposal of the residual brine implies salinization of soil and eutrophication of water. Since most of the organic load of the waste brines comes from proteins leaked from the salted product, precipitation of dissolved proteins by acidification and removal by centrifugation is an operation to be used in waste brine cleaning. The aim of this study is optimizing the conditions for carrying out the separation of proteins from waste brines generated in the pork ham salting operation, by studying the influence of pH, centrifugal force, and centrifugation time. Models for determining the removal of proteins depending on the pH, centrifugal force, and time were obtained. The results showed a high efficacy of the proposed treatment for removing proteins, suggesting that this method could be used for waste brine protein removal. The best pH value to be used in an industrial process seems to be 3, while the obtained results indicate that almost 90% of the proteins from the brine can be removed by acidification followed by centrifugation. A further protein removal from the brine should have to be achieved using filtrating techniques, which efficiency could be highly improved as a consequence of the previous treatment through acidification and centrifugation. Waste brines from meat salting have high organic load and electrical conductivity. Proteins can be removed from the waste brine by acidification and centrifugation. The total protein removal can be up to 90% of the initial content of the waste brine. Protein removal is highly dependent on pH, centrifugation rate, and time. © 2014 Institute of Food Technologists®

  15. Laser tracker TSPI uncertainty quantification via centrifuge trajectory

    Science.gov (United States)

    Romero, Edward; Paez, Thomas; Brown, Timothy; Miller, Timothy

    2009-08-01

    Sandia National Laboratories currently utilizes two laser tracking systems to provide time-space-position-information (TSPI) and high speed digital imaging of test units under flight. These laser trackers have been in operation for decades under the premise of theoretical accuracies based on system design and operator estimates. Advances in optical imaging and atmospheric tracking technology have enabled opportunities to provide more precise six degree of freedom measurements from these trackers. Applying these technologies to the laser trackers requires quantified understanding of their current errors and uncertainty. It was well understood that an assortment of variables contributed to laser tracker uncertainty but the magnitude of these contributions was not quantified and documented. A series of experiments was performed at Sandia National Laboratories large centrifuge complex to quantify TSPI uncertainties of Sandia National Laboratories laser tracker III. The centrifuge was used to provide repeatable and economical test unit trajectories of a test-unit to use for TSPI comparison and uncertainty analysis. On a centrifuge, testunits undergo a known trajectory continuously with a known angular velocity. Each revolution may represent an independent test, which may be repeated many times over for magnitudes of data practical for statistical analysis. Previously these tests were performed at Sandia's rocket sled track facility but were found to be costly with challenges in the measurement ground truth TSPI. The centrifuge along with on-board measurement equipment was used to provide known ground truth position of test units. This paper discusses the experimental design and techniques used to arrive at measures of laser tracker error and uncertainty.

  16. Centrifugal-reciprocating compressor

    Science.gov (United States)

    Higa, W. H. (Inventor)

    1984-01-01

    A centrifugal compressor is described which includes at least one pair of cylinders arranged in coaxial alignment and supported for angular displacement about a common axis of rotation normally disecting a common longitudinal axis of symmetry for the cylinders. The cylinders are characterized by ported closures located at the mutually remote ends thereof through which the cylinders are charged and discharged, and a pair of piston heads seated within the cylinders and supported for floating displacement in compressive strokes in response to unidirectional angular displacement imparted to the cylinders.

  17. Numerical and experimental analysis of the sedimentation of spherical colloidal suspensions under centrifugal force

    Science.gov (United States)

    Antonopoulou, Evangelia; Rohmann-Shaw, Connor F.; Sykes, Thomas C.; Cayre, Olivier J.; Hunter, Timothy N.; Jimack, Peter K.

    2018-03-01

    Understanding the sedimentation behaviour of colloidal suspensions is crucial in determining their stability. Since sedimentation rates are often very slow, centrifugation is used to expedite sedimentation experiments. The effect of centrifugal acceleration on sedimentation behaviour is not fully understood. Furthermore, in sedimentation models, interparticle interactions are usually omitted by using the hard-sphere assumption. This work proposes a one-dimensional model for sedimentation using an effective maximum volume fraction, with an extension for sedimentation under centrifugal force. A numerical implementation of the model using an adaptive finite difference solver is described. Experiments with silica suspensions are carried out using an analytical centrifuge. The model is shown to be a good fit with experimental data for 480 nm spherical silica, with the effects of centrifugation at 705 rpm studied. A conversion of data to Earth gravity conditions is proposed, which is shown to recover Earth gravity sedimentation rates well. This work suggests that the effective maximum volume fraction accurately captures interparticle interactions and provides insights into the effect of centrifugation on sedimentation.

  18. Numerical simulation of dynamic flow characteristics in a centrifugal water pump with three-vaned diffuser

    Directory of Open Access Journals (Sweden)

    Zhi-Jun Shuai

    2015-08-01

    Full Text Available The complex three-dimensional turbulent flow field in a centrifugal water pump with three asymmetrical diffusers was numerically simulated. The characteristics of pressure and force fluctuations inside the model pump were investigated. Fast Fourier transformation was performed to obtain the spectra of pressure and force fluctuations. It indicates that the dominant frequency of pressure fluctuations is the blade passing frequency in all the sub-domains inside the pump and the first blade passing frequency energy (first order of blade passing frequency is the most significant. The dominant frequency of pressure fluctuations at the location of diffuser outlet is featured by low frequency (less than 1 Hz, which may be due to the locally generated eddy structures. Besides, the dominant frequency force fluctuations on the impeller blades are also the blade passing frequency. The existence of the three asymmetrical diffusers has damping effect on the pressure fluctuation amplitude and energy amplitude of pressure fluctuations in the diffuser domain dramatically, which indicates that the diffusers can effectively control the hydraulically excited vibration in the pump. Besides, the prediction of the dominant frequency of pressure fluctuations inside the pump can help to utilize the pump effectively and to extend the pump life. The main findings of this work can provide prediction of the pump performance and information for further optimal design of centrifugal pumps as well.

  19. Solidified structure of thin-walled titanium parts by vertical centrifugal casting

    Directory of Open Access Journals (Sweden)

    Wu Shiping

    2011-05-01

    Full Text Available The solidified structure of the thin-walled and complicated Ti-6Al-4V castings produced by the vertical centrifugal casting process was studied in the present work. The results show that the wall thickness of the section is featured with homogeneously distributed fine equiaxial grains, compared with the microstructure of the thick-walled section. The grain size of the castings has a tendency to decrease gradually with the increasing of the centrifugal radius. The inter-lamellar space in thick-walled casting parts is bigger than that of the thin-walled parts, and the profile of inter-lamellar space is not susceptible to the centrifugal radius.

  20. Experiments with background gas in a vacuum arc centrifuge

    International Nuclear Information System (INIS)

    Dallaqua, R.S.; Simpson, S.W.; Del Bosco, E.

    1996-01-01

    Since promising isotope separation results were first reported by Krishnan et al. in 1981, a range of vacuum arc centrifuge experiments have been conducted in laboratories around the world. The PCEN (Plasma CENtrifuge) vacuum arc centrifuge at the Brazilian National Institute for Space Research has been used for isotope separation studies with cathode materials of carbon and magnesium and also to investigate the performance in terms of the rotational velocity attained for different cathode materials. Here, a vacuum arc centrifuge has been operated with an initial filling gas of either argon or hydrogen for pressures ranging from 10 -3 to 10 -1 Pa. The angular velocity ω of the plasma has been determined by cross-correlating the signals from potential probes, and the electron temperature T has been deduced from Langmuir probe data. At high gas pressures and early times during the 14 ms plasma lifetime, high-frequency nonuniformities frequently observed in the vacuum discharge disappear, suggesting that the associated instability is suppressed. Under the same conditions, nonuniformities rotating with much lower angular velocities are observed in the plasma. Temperatures are reduced in the presence of the background gas, and the theoretical figure of merit for separation proportional to ω 2 /T is increased compared to its value in the vacuum discharge for both argon and hydrogen gas fillings

  1. Why have we stopped research on liquid centrifugal separation

    International Nuclear Information System (INIS)

    Li, N.

    1996-01-01

    Using high-temperature high-speed liquid centrifuges for lanthanides and actinides separation was originally proposed as a physical separation method in the Los Alamos ADTT/ATW concept [C. Bowman, LA-UR-92-1065 (1992)]. The authors investigated centrifugal separation in a concerted effort of experiments, theoretical analysis and numerical simulations. They discovered that owing to the ionic-composition-dependence of the sedimentation coefficients for the fission products and actinides, separation by grouping of molecular densities would not work in general in the molten salt environment. Alternatively the lanthanides and actinides could be transferred to a liquid metal carrier (e.g. bismuth) via reductive extraction and then separated by liquid centrifuges, but the material and technical challenges are severe. Meanwhile the authors have established that the reductive extraction procedure itself can be used for desired separations. Unlike conventional aqueous-based reprocessing technologies, reductive extraction separation uses only reagent (Li) that reconstitutes carrier salts (LiF-BeF 2 ) and a processing medium (Bi) that can be continuously recycled and reused, with a nearly-pure fission products waste stream. The processing units are compact and reliable, and can be built at relatively low cost while maintaining high throughput. Therefore the research effort on developing liquid centrifuges for separations in ADTT/ATW was terminated in late 1995. This paper will discuss the various aspects involved in reaching this decision

  2. An Investigation of Backflow Phenomenon in Centrifugal Compressors

    Science.gov (United States)

    Benser, William A; Moses, Jason J

    1945-01-01

    Report presents the results of an investigation conducted to determine the nature and the extent of the reversal of flow, which occurs at the inlet of centrifugal compressors over a considerable portion of the operating range. Qualitative studies of this flow reversal were made by lampblack patterns taken on a mixed-flow-type impeller and by tuft studies made on a conventional centrifugal compressor. Quantitative studies were made on a compressor specially designed to enable survey of angularity of flow, static and total pressures, and temperatures to be taken very close to the impeller front housing.

  3. Multiplexed single-molecule force spectroscopy using a centrifuge.

    Science.gov (United States)

    Yang, Darren; Ward, Andrew; Halvorsen, Ken; Wong, Wesley P

    2016-03-17

    We present a miniature centrifuge force microscope (CFM) that repurposes a benchtop centrifuge for high-throughput single-molecule experiments with high-resolution particle tracking, a large force range, temperature control and simple push-button operation. Incorporating DNA nanoswitches to enable repeated interrogation by force of single molecular pairs, we demonstrate increased throughput, reliability and the ability to characterize population heterogeneity. We perform spatiotemporally multiplexed experiments to collect 1,863 bond rupture statistics from 538 traceable molecular pairs in a single experiment, and show that 2 populations of DNA zippers can be distinguished using per-molecule statistics to reduce noise.

  4. 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...

  5. High-speed centrifugation induces aggregation of extracellular vesicles.

    Science.gov (United States)

    Linares, Romain; Tan, Sisareuth; Gounou, Céline; Arraud, Nicolas; Brisson, Alain R

    2015-01-01

    Plasma and other body fluids contain cell-derived extracellular vesicles (EVs), which participate in physiopathological processes and have potential biomedical applications. In order to isolate, concentrate and purify EVs, high-speed centrifugation is often used. We show here, using electron microscopy, receptor-specific gold labelling and flow cytometry, that high-speed centrifugation induces the formation of EV aggregates composed of a mixture of EVs of various phenotypes and morphologies. The presence of aggregates made of EVs of different phenotypes may lead to erroneous interpretation concerning the existence of EVs harbouring surface antigens from different cell origins.

  6. High-speed centrifugation induces aggregation of extracellular vesicles

    Directory of Open Access Journals (Sweden)

    Romain Linares

    2015-12-01

    Full Text Available Plasma and other body fluids contain cell-derived extracellular vesicles (EVs, which participate in physiopathological processes and have potential biomedical applications. In order to isolate, concentrate and purify EVs, high-speed centrifugation is often used. We show here, using electron microscopy, receptor-specific gold labelling and flow cytometry, that high-speed centrifugation induces the formation of EV aggregates composed of a mixture of EVs of various phenotypes and morphologies. The presence of aggregates made of EVs of different phenotypes may lead to erroneous interpretation concerning the existence of EVs harbouring surface antigens from different cell origins.

  7. Isolation of Mycobacterium chelonei with the lysis-centrifugation blood culture technique.

    OpenAIRE

    Fojtasek, M F; Kelly, M T

    1982-01-01

    Mycobacterium chelonei was isolated from a patient by the lysis-centrifugation and the conventional two-bottle blood culture methods. The lysis-centrifugation method was significantly more sensitive and rapid than the conventional method in detecting and isolating this organism; quantitations done by this method were useful for monitoring response to therapy.

  8. 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.

  9. Optimizing platelet-rich plasma gel formation by varying time and gravitational forces during centrifugation.

    Science.gov (United States)

    Jo, Chris H; Roh, Young Hak; Kim, Ji Eun; Shin, Sue; Yoon, Kang Sup

    2013-10-01

    Despite the increasing clinical use of topical platelet-rich plasma (PRP) to enhance tissue healing and regeneration, there is no properly standardized method of autologous PRP gel preparation. This study examined the effect of the centrifugation time and gravitational force (g) on the platelet recovery ratio of PRP and determined the most effective centrifugation conditions for preparing PRP. Two-step centrifugations for preparing PRP were used in 39 subjects who had consented prior to the study's start. The separating centrifugation (Step 1, used to separate whole blood into its two main components: red blood cells and plasma) was tested from 500g to 1900g at 200g increments for 5 minutes (min), and from 100g to 1300g at 200g increments for 10 minutes. After separating centrifugation, upper plasma layer was transferred to another plain tube for the condensation centrifugation and remaining lower cell layer was discarded. The condensation centrifugation (Step 2, used to condense the platelets in the separated plasma) was tested at 1000g for 15 min, 1500g for 15 min, 2000g for 5 min and 3000g for 5 min, additionally at 1000g for 10 min and 1500g for 10 min. Platelet gelation was induced by adding 10% calcium gluconate to final PRP with volume ratio of 1:10. The optimal separating centrifugation conditions were followed by 900g for 5 minutes and the condensation conditions were followed by 1500g for 15 minutes, of which recovery ratios were 92.0 ± 3.1% and 84.3 ± 10.0%, respectively.

  10. Life Sciences Centrifuge Facility assessment

    Science.gov (United States)

    Benson, Robert H.

    1994-01-01

    This report provides an assessment of the status of the Centrifuge Facility being developed by ARC for flight on the International Space Station Alpha. The assessment includes technical status, schedules, budgets, project management, performance of facility relative to science requirements, and identifies risks and issues that need to be considered in future development activities.

  11. Basic characteristics of a low uranium enrichment cascade by centrifugation, (2)

    International Nuclear Information System (INIS)

    Kai, Tsunetoshi

    1975-01-01

    The theory for a cascade of centrifuges described in the preceding report of the same general title is further developed. First, equations describing the distributions of the flow and the mole concentration are derived from the material balance relations for a square cascade. Corresponding equations are next obtained to cover a squared-off cascade consisting of a series of square cascades. A computer program is outlined which makes it possible to obtain the shape of the most efficient squared-off cascade. The efficiency of the current form of squared-off centrifuge cascade with reflux pipes is found to be lower than obtainable with gaseous diffusion. The efficiency can be improved by the adoption of a tapered squared-off cascade with centrifuges provided with eccentric cuts to take the place of reflux pipes. The dynamic characteristics are also discussed. Analysis of the start-up behavior reveals that the equilibrium time of the centrifuge cascade is much shorter than for a coresponding gaseous diffusion cascade, and that the mole concentration of the product rapidly rises to attain steady state condition. It is also found that even when the feed flow rate fluctuates, the mole concentration of the product is relatively stable. The effect of a centrifuge failure in the cascade is examined. The optimum mole concentration for the waste effluent discarded from the cascade is calculated from the viewpoint of cost. (auth.)

  12. Solid deuterium centrifuge pellet injector

    International Nuclear Information System (INIS)

    Foster, C.A.

    1982-01-01

    Pellet injectors are needed to fuel long pulse tokamak plasmas and other magnetic confinement devices. For this purpose, an apparatus has been developed that forms 1.3-mm-diam pellets of frozen deuterium at a rate of 40 pellets per second and accelerates them to a speed of 1 km/s. Pellets are formed by extruding a billet of solidified deuterium through a 1.3-mm-diam nozzle at a speed of 5 cm/s. The extruding deuterium is chopped with a razor knife, forming 1.3-mm right circular cylinders of solid deuterium. The pellets are accelerated by synchronously injecting them into a high speed rotating arbor containing a guide track, which carries them from a point near the center of rotation to the periphery. The pellets leave the wheel after 150 0 of rotation at double the tip speed. The centrifuge is formed in the shape of a centrifugal catenary and is constructed of high strength KEVLAR/epoxy composite. This arbon has been spin-tested to a tip speed of 1 km/s

  13. Solid deuterium centrifuge pellet injector

    International Nuclear Information System (INIS)

    Foster, C.A.

    1983-01-01

    Pellet injectors are needed to fuel long pulse tokamak plasmas and other magnetic confinement devices. For this purpose, an apparatus has been developed that forms 1.3-mm-diam pellets of frozen deuterium at a rate of 40 pellets per second and accelerates them to a speed of 1 km/s. Pellets are formed by extruding a billet of solidified deuterium through a 1.3-mm-diam nozzle at a speed of 5 cm/s. The extruding deuterium is chopped with a razor knife, forming 1.3-mm right circular cylinders of solid deuterium. The pellets are accelerated by synchronously injecting them into a high speed rotating arbor containing a guide track, which carries them from a point near the center of rotation to the periphery. The pellets leave the wheel after 150 0 of rotation at double the tip speed. The centrifuge is formed in the shape of a centrifugal catenary and is constructed of high strength Kevlar/epoxy composite. This arbor has been spin-tested to a tip speed of 1 km/s

  14. Development and industrial application of gas centrifuges to uranium enrichment in the USSR

    International Nuclear Information System (INIS)

    Abbakumov, E.I.; Bazhenov, V.A.; Verbin, Yu.V.

    1989-01-01

    Review of state and studies in the field of gaseous diffusion technology and centrifugal method of uranium enrichment in the USSR is given. Domestic industrial gas centrifuges, forming to-day the main part of separation capacities in the USSR, are noted for low specific energy consumption and high reliability. Centrifugal technology in the USSR is applied both to uranium enrichment (including one for export) and to separation of isotopes of other chemical elements

  15. High stability design for new centrifugal compressor

    Science.gov (United States)

    Kanki, H.; Katayama, K.; Morii, S.; Mouri, Y.; Umemura, S.; Ozawa, U.; Oda, T.

    1989-01-01

    It is essential that high-performance centrifugal compressors be free of subsynchronous vibrations. A new high-performance centrifugal compressor has been developed by applying the latest rotordynamics knowledge and design techniques: (1) To improve the system damping, a specially designed oil film seal was developed. This seal attained a damping ratio three times that of the conventional design. The oil film seal contains a special damper ring in the seal cartridge. (2) To reduce the destabilizing effect of the labyrinth seal, a special swirl canceler (anti-swirl nozzle) was applied to the balance piston seal. (3) To confirm the system damping margin, the dynamic simulation rotor model test and the full load test applied the vibration exciting test in actual load conditions.

  16. 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.

  17. Root resistance to cavitation is accurately measured using a centrifuge technique.

    Science.gov (United States)

    Pratt, R B; MacKinnon, E D; Venturas, M D; Crous, C J; Jacobsen, A L

    2015-02-01

    Plants transport water under negative pressure and this makes their xylem vulnerable to cavitation. Among plant organs, root xylem is often highly vulnerable to cavitation due to water stress. The use of centrifuge methods to study organs, such as roots, that have long vessels are hypothesized to produce erroneous estimates of cavitation resistance due to the presence of open vessels through measured samples. The assumption that roots have long vessels may be premature since data for root vessel length are sparse; moreover, recent studies have not supported the existence of a long-vessel artifact for stems when a standard centrifuge technique was used. We examined resistance to cavitation estimated using a standard centrifuge technique and compared these values with native embolism measurements for roots of seven woody species grown in a common garden. For one species we also measured vulnerability using single-vessel air injection. We found excellent agreement between root native embolism and the levels of embolism measured using a centrifuge technique, and with air-seeding estimates from single-vessel injection. Estimates of cavitation resistance measured from centrifuge curves were biologically meaningful and were correlated with field minimum water potentials, vessel diameter (VD), maximum xylem-specific conductivity (Ksmax) and vessel length. Roots did not have unusually long vessels compared with stems; moreover, root vessel length was not correlated to VD or to the vessel length of stems. These results suggest that root cavitation resistance can be accurately and efficiently measured using a standard centrifuge method and that roots are highly vulnerable to cavitation. The role of root cavitation resistance in determining drought tolerance of woody species deserves further study, particularly in the context of climate change. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Coalescence and compression in centrifuged emulsions studied with in situ optical microscopy

    NARCIS (Netherlands)

    Krebs, T.; Ershov, D.S.; Schroën, C.G.P.H.; Boom, R.M.

    2013-01-01

    We report an experimental method to investigate droplet dynamics in centrifuged emulsions and its application to study droplet compression and coalescence. The experimental setup permits in situ monitoring of an ensemble of droplets in a centrifuged monolayer of monodisperse emulsion droplets using

  19. Laser-based data acquisition in gas centrifuge environments using optical fibers

    International Nuclear Information System (INIS)

    Cates, M.R.; Allison, S.W.; Marshall, B.; Davies, T.J.; Franks, L.A.; Nelson, M.A.; Noel, B.W.

    1984-01-01

    The operating environment of gas centrifuges poses three basic experimental problems: rotating reference frame, corrosive effects of UF 6 gas, and vacuum coupling. Diagnostic experiments in this environment effectively use fiber optics as laser transport systems and data extraction channels. Access to the interior of rotating centrifuges is only from a central nonrotating column assembly. Optical paths are often long and difficult to measure in static conditions with precision necessary in operating conditions. Residual traces of HF gas, from UF 6 , damage exposed optical components over time. Diagnostic measurements requiring pulsed laser sources and analysis of fluorescence emissions, both from UF 6 gas and from temperature-sensitive phosphor are described, with emphasis on optical fiber components and experimental design configurations. The studies were done at Oak Ridge Gaseous Diffusion Plant through the Centrifuge Physics Department of the Centrifuge Division. The advantages of fiber optics methods include: optical path flexibility, small and adaptable size of components, utility in connection with moveable assemblies, and relative ease of vacuum isolation. 3 references, 6 figures

  20. 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 casting...

  1. Comparison of 30-2 Standard and Fast programs of Swedish Interactive Threshold Algorithm of Humphrey Field Analyzer for perimetry in patients with intracranial tumors.

    Science.gov (United States)

    Singh, Manav Deep; Jain, Kanika

    2017-11-01

    To find out whether 30-2 Swedish Interactive Threshold Algorithm (SITA) Fast is comparable to 30-2 SITA Standard as a tool for perimetry among the patients with intracranial tumors. This was a prospective cross-sectional study involving 80 patients aged ≥18 years with imaging proven intracranial tumors and visual acuity better than 20/60. The patients underwent multiple visual field examinations using the two algorithms till consistent and repeatable results were obtained. A total of 140 eyes of 80 patients were analyzed. Almost 60% of patients undergoing perimetry with SITA Standard required two or more sessions to obtain consistent results, whereas the same could be obtained in 81.42% with SITA Fast in the first session itself. Of 140 eyes, 70 eyes had recordable field defects and the rest had no defects as detected by either of the two algorithms. Mean deviation (MD) (P = 0.56), pattern standard deviation (PSD) (P = 0.22), visual field index (P = 0.83) and number of depressed points at P 0.5% on MD and PSD probability plots showed no statistically significant difference between two algorithms. Bland-Altman test showed that considerable variability existed between two algorithms. Perimetry performed by SITA Standard and SITA Fast algorithm of Humphrey Field Analyzer gives comparable results among the patients of intracranial tumors. Being more time efficient and with a shorter learning curve, SITA Fast my be recommended as a standard test for the purpose of perimetry among these patients.

  2. EM Task 9 - Centrifugal membrane filtration

    International Nuclear Information System (INIS)

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

    1999-01-01

    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. 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.

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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. (paper)

  5. Smoothed Particle Hydro-dynamic Analysis of Improvement in Sludge Conveyance Efficiency of Screw Decanter Centrifuge

    Energy Technology Data Exchange (ETDEWEB)

    Park, Dae Woong [Korea Testing and Research Institute, Kwachun (Korea, Republic of)

    2015-03-15

    A centrifuge works on the principle that particles with different densities will separate at a rate proportional to the centrifugal force during high-speed rotation. Dense particles are quickly precipitated, and particles with relatively smaller densities are precipitated more slowly. A decanter-type centrifuge is used to remove, concentrate, and dehydrate sludge in a water treatment process. This is a core technology for measuring the sludge conveyance efficiency improvement. In this study, a smoothed particle hydro-dynamic analysis was performed for a decanter centrifuge used to convey sludge to evaluate the efficiency improvement. This analysis was applied to both the original centrifugal model and the design change model, which was a ball-plate rail model, to evaluate the sludge transfer efficiency.

  6. Smoothed Particle Hydro-dynamic Analysis of Improvement in Sludge Conveyance Efficiency of Screw Decanter Centrifuge

    International Nuclear Information System (INIS)

    Park, Dae Woong

    2015-01-01

    A centrifuge works on the principle that particles with different densities will separate at a rate proportional to the centrifugal force during high-speed rotation. Dense particles are quickly precipitated, and particles with relatively smaller densities are precipitated more slowly. A decanter-type centrifuge is used to remove, concentrate, and dehydrate sludge in a water treatment process. This is a core technology for measuring the sludge conveyance efficiency improvement. In this study, a smoothed particle hydro-dynamic analysis was performed for a decanter centrifuge used to convey sludge to evaluate the efficiency improvement. This analysis was applied to both the original centrifugal model and the design change model, which was a ball-plate rail model, to evaluate the sludge transfer efficiency.

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

    International Nuclear Information System (INIS)

    Robertson, E.

    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

  8. Centrifuge in Free Fall: Combustion at Partial Gravity

    Science.gov (United States)

    Ferkul, Paul

    2017-01-01

    A centrifuge apparatus is developed to study the effect of variable acceleration levels in a drop tower environment. It consists of a large rotating chamber, within which the experiment is conducted. NASA Glenn Research Center 5.18-second Zero-Gravity Facility drop tests were successfully conducted at rotation rates up to 1 RPS with no measurable effect on the overall Zero-Gravity drop bus. Arbitrary simulated gravity levels from zero to 1-g (at a radius of rotation 30 cm) were produced. A simple combustion experiment was used to exercise the capabilities of the centrifuge. A total of 23 drops burning a simulated candle with heptane and ethanol fuel were performed. The effect of gravity level (rotation rate) and Coriolis force on the flames was observed. Flames became longer, narrower, and brighter as gravity increased. The Coriolis force tended to tilt the flames to one side, as expected, especially as the rotation rate was increased. The Zero-Gravity Centrifuge can be a useful tool for other researchers interested in the effects of arbitrary partial gravity on experiments, especially as NASA embarks on future missions which may be conducted in non-Earth gravity.

  9. Determination of a suitable set of loss models for centrifugal compressor performance prediction

    Directory of Open Access Journals (Sweden)

    Elkin I. GUTIÉRREZ VELÁSQUEZ

    2017-10-01

    Full Text Available Performance prediction in preliminary design stages of several turbomachinery components is a critical task in order to bring the design processes of these devices to a successful conclusion. In this paper, a review and analysis of the major loss mechanisms and loss models, used to determine the efficiency of a single stage centrifugal compressor, and a subsequent examination to determine an appropriate loss correlation set for estimating the isentropic efficiency in preliminary design stages of centrifugal compressors, were developed. Several semi-empirical correlations, commonly used to predict the efficiency of centrifugal compressors, were implemented in FORTRAN code and then were compared with experimental results in order to establish a loss correlation set to determine, with good approximation, the isentropic efficiency of single stage compressor. The aim of this study is to provide a suitable loss correlation set for determining the isentropic efficiency of a single stage centrifugal compressor, because, with a large amount of loss mechanisms and correlations available in the literature, it is difficult to ascertain how many and which correlations to employ for the correct prediction of the efficiency in the preliminary stage design of a centrifugal compressor. As a result of this study, a set of correlations composed by nine loss mechanisms for single stage centrifugal compressors, conformed by a rotor and a diffuser, are specified.

  10. Review of noise reduction methods for centrifugal fans

    Science.gov (United States)

    Neise, W.

    1981-11-01

    Several methods for the reduction of centrifugal fan noise are presented, the most of which are aimed at a lower blade passage frequency level. The methods are grouped into five categories: casing modifications to increase the distance between impeller and cutoff, the introduction of a phase shift of the source pressure fluctuations, impeller modifications, radial clearance between impeller eye and inlet nozzle, and acoustical measures. Resonators mounted at the cutoff of centrifugal fans appear to be a highly efficient and simple means of reducing the blade passage tone, and the method can be used for new fan construction and existing installations without affecting the aerodynamic performance of the fan.

  11. Flow in a centrifugal fan impeller at off-design conditions

    Science.gov (United States)

    Wright, T.; Tzou, K. T. S.; Madhavan, S.

    1984-06-01

    A fully three-dimensional finite element analysis of inviscid, incompressible blade channel flow is the basis of the present study of both predicted and measured surface velocity and pressure distributions in the internal flow channels of a centrifugal fan impeller, for volume flow rates of 80-125 percent the design flow rate. The experimental results made extensive use of blade and sidewall surface pressure taps installed in a scale model of an airfoil-bladed centrifugal fan impeller. The results obtained illustrate the ability of both flow analyses to predict the dominant features of the impeller flow field, including peak blade surface velocities and adverse gradients at flows far from the design point. Insight is also gained into the limiting channel diffusion values for typical centrifugal cascade performance, together with the influence of viscous effects, as seen in deviations from ideal flow predictions.

  12. Centrifuge Modelling of Two Civil-Environmental Problems

    National Research Council Canada - National Science Library

    Goodings, Deborah

    2001-01-01

    Research Problem 1: Frost heave and thaw induced settlement in silt and silty clay developing over a year have been modelled correctly using a geotechnical centrifuge with tests requiring less than a day...

  13. National geotechnical centrifuge

    Science.gov (United States)

    Hallam, J. A.; Kunz, N.; Vallotton, W. C.

    1982-01-01

    A high G-ton centrifuge, able to take a 2700 kg (6000 lb) payload up to 300 G, is described. The stability of dams and embankments, the bearing capacity of soil foundations, and the dynamic behavior of foundations due to vibration of machinery are examples of applications. A power rating of 6,000 kW (9,000 hp) was established for the motor. An acceptable maximum speed of 70 rpm was determined. A speed increase with a ratio of 1:3 is discussed. The isolated tension straps, the anti-spreader bar and the flexwall bucket, and safety precautions are also discussed.

  14. Present status of centrifuge method for uranium enrichment and PNC plant

    International Nuclear Information System (INIS)

    Nishikido, Yoshikazu

    1977-01-01

    Recentry, the tendency to adopt atomic energy owing to the oil shock, the delay in the construction of nuclear power stations worldwide, the uncertainty in the utilization of plutonium, and the prospect of supplying natural uranium are the situations affecting uranium enrichment. Anyway, the enrichment capacity in the world must be increased by the early years of 1980 s. The uranium enrichment technology by centrifugal method is being developed in various countries under strict control of informations, therefore the details are not known, but the general state in Great Britain, F.R. of Germany, Netherlands, U.S.A. and Japan is explained. The development of the centrifugal enrichment method in Japan was designated in 1972 as the national project aiming at operating the enriching plant with international competitive power by 1985. The PNC undertook the development work, and the research and development include the development of a centrifuge, cascade test, life span test, the development of the mass production technology, and safety test. The especially notable matter in this period was the rapid progress of a supercritical type centrifuge. It is judged that the technical basis for constructing a pilot plant has been established. The site for the pilot plant is being prepared now in the Ningyo Pass Mine, PNC, and the enrichment plant with 7000 centrifuges will be constructed there. The outline of the plant and the schedule for the construction are described. (Kako, I.)

  15. Rapid detection and quantification of cell free cytomegalovirus by a high-speed centrifugation-based microculture assay: comparison to longitudinally analyzed viral DNA load and pp67 late transcript during lactation.

    Science.gov (United States)

    Hamprecht, Klaus; Witzel, Simone; Maschmann, Jens; Dietz, Klaus; Baumeister, Andrea; Mikeler, Elfriede; Goelz, Rangmar; Speer, Christian P; Jahn, Gerhard

    2003-12-01

    Human cytomegalovirus (HCMV) is reactivated in nearly every seropositive breastfeeding mother during lactation [Lancet 357 (2001) 513]. Conventional tissue culture (TC) and low-speed centrifugation-enhanced microtiter culture methods are not able to detect HCMV from milk during all stages of lactation. Development of a sensitive and quantitative microculture technique to describe the dynamics of HCMV reactivation in different milk compartments during lactation. Milk samples were collected longitudinally from seropositive breastfeeding mothers of preterm infants. Native milk samples were separated into fraction 1 (aqueous extract of milk fat), fraction 2 (cell and fat free milk whey) and fraction 3 (milk cells). Each of these fractions was screened qualitatively (TC, nPCR, pp67 late mRNA) and quantitatively (high-speed centrifugation-based microculture, quantitative PCR). Prior to low-speed centrifugation-enhanced inoculation, virus particles were concentrated by high-speed centrifugation (60 min at 50,000 x g, 4 degrees C). Using fraction 2 we were able to describe the dynamics of viral reactivation during lactation. We present the course of the quantitative virolactia and DNAlactia and qualitative detection of HCMV pp67 late mRNA in milk whey of four mothers (three transmitters and one non-transmitter). In all these cases virolactia described an unimodal and self limited course. Peak levels of virolactia for transmitters (T1: day 44; T2: day 43; T3: day 50) were closely related the onset of viruria of the corresponding preterm infants (U1: day 39; U2a/U2b: day 44/57; U3: day 60). The courses of viral load coincidence with the courses of DNA load. We present a rapid and highly sensitive microculture method for the quantification of cell free HCMV from milk whey and aqueous extracts from milk fat. Viral reactivation during lactation describes an unimodal course. Our findings have strong implications for quality control of any virus inactivation procedure.

  16. Role of centrifugal and charge effects of the mass separation in a plasma centrifuge with crossed fields

    International Nuclear Information System (INIS)

    Zhdanov, V.M.; Karchevskii, A.I.; Lukovnikov, A.I.; Potanin, E.P.

    1982-01-01

    The coefficients of mass separation have been calculated for gas mixtures in crossed electric and magnetic fields. The initial kinetic equations have been derived, and the contribution of centrifugal and charge separation mechanisms to mass separation in a weakly ionized plasma has been assessed

  17. Elements for modeling and design of centrifugal compressor housings

    International Nuclear Information System (INIS)

    Magoia, J.E.; Calderon, T.

    1990-01-01

    Various aspects of the structural analysis of centrifugal compressor housings are studied. These are usually used in different kinds of nuclear sites. Multiple areas of the analysis are evaluated with elastic models based on finite elements: sensitivity to different variables, quality of models on facing theoretical solutions and performed measurements. The development of an excentric bar element improved for the rigidized plate model, is included. The definition of criteria for a more efficient structural analysis as well as recommendations for the design of centrifugal compressor housings concludes the work. (Author) [es

  18. Numerical Investigations of Unsteady Flow in a Centrifugal Pump with a Vaned Diffuser

    Directory of Open Access Journals (Sweden)

    Olivier Petit

    2013-01-01

    Full Text Available Computational fluid dynamics (CFD analyses were made to study the unsteady three-dimensional turbulence in the ERCOFTAC centrifugal pump test case. The simulations were carried out using the OpenFOAM Open Source CFD software. The test case consists of an unshrouded centrifugal impeller with seven blades and a radial vaned diffuser with 12 vanes. A large number of measurements are available in the radial gap between the impeller and the diffuse, making this case ideal for validating numerical methods. Results of steady and unsteady calculations of the flow in the pump are compared with the experimental ones, and four different turbulent models are analyzed. The steady simulation uses the frozen rotor concept, while the unsteady simulation uses a fully resolved sliding grid approach. The comparisons show that the unsteady numerical results accurately predict the unsteadiness of the flow, demonstrating the validity and applicability of that methodology for unsteady incompressible turbomachinery flow computations. The steady approach is less accurate, with an unphysical advection of the impeller wakes, but accurate enough for a crude approximation. The different turbulence models predict the flow at the same level of accuracy, with slightly different results.

  19. Laser and gas centrifuge enrichment

    Energy Technology Data Exchange (ETDEWEB)

    Heinonen, Olli [Senior Fellow, Belfer Center for Science and International Affairs, Harvard Kennedy School, Cambridge, Massachusetts (United States)

    2014-05-09

    Principles of uranium isotope enrichment using various laser and gas centrifuge techniques are briefly discussed. Examples on production of high enriched uranium are given. Concerns regarding the possibility of using low end technologies to produce weapons grade uranium are explained. Based on current assessments commercial enrichment services are able to cover the global needs of enriched uranium in the foreseeable future.

  20. Gas centrifuge bibliography 1983-1986

    International Nuclear Information System (INIS)

    Lowe, G.E.; McLeod, D.F.; Roberts, P.

    1987-03-01

    A bibliography is presented of the gas centrifuge literature published from 1983-1986 inclusive. It supplements PG Information Series 25(CA), BNFL Information Series 15(CA), BNFL Information Series 23 (CA), and BNFL Information Series 27(CA), which together cover the period 1895-1982. The main arrangement is chronological and there are author, report number, and subject indexes. (U.K.)

  1. 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.

  2. 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.

  3. Separative performance transients in a gas centrifuge

    International Nuclear Information System (INIS)

    Olander, D.R.

    1979-01-01

    A general method has been developed to calculate the behavior of the exit compositions from a gas centrifuge under unsteady conditions. The method utilizes the basic enrichment gradient equations derived by Cohen, which, in this case, contain time derivatives of the partial 235 U inventories. These partial differential equations are converted to ordinary differential equations by a linear approximation to the axial concentration distribution for use in the inventory terms only. With this simplification, analytical solution is possible for the feed concentration transient. The transient driven by a change in the feed flow rate, however, requires numerical solution. For analysis of ideal cascades in the unsteady state, the transient flow and separation characteristics of the centrifuge must be combined with total uranium and 235 U material balances on each stage

  4. Effect of hypergravity on catecholamine levels in telemetrically collected blood of rats during centrifugation

    Science.gov (United States)

    Kvetnansky, R.; Petrak, J.; Mravec, B.; Tillinger, A.; Jurani, M.; Baranovska, M.; Hapala, I.; Frollo, I.

    2005-08-01

    Hypergravity is known to activate the sympathoadrenal system (SAS). Rats subjected to various accelerations (+G) exhibited increased levels of plasma epinephrine (EPI) and partly also norepinephrine (NE). However, the collection of blood was performed after centrifugation finished and therefore plasma NE and EPI levels could have been affected by the process of deceleration. The aim of this study was to evaluate plasma EPI and NE levels in blood collected directly during the centrifugation after reaching different +G, using newly developed remote controlled equipment. Such telemetrically regulated equipment for multiple blood sampling allows us to investigate selective effects of hypergravity during centrifugation. All animals had a polyethylene tubing in the tail artery which was connected to a pre-programmed device for three blood withdrawals (0.6 ml each) into individual syringes, performed at any chosen time intervals. Plasma EPI and NE levels were measured at hypergravity between +1G - +5G. Plasma EPI levels showed a huge, hypergravity dependent increase at the interval of 10-20 min. After the blood collection was completed, the centrifuge was turned off and another blood sampling was performed immediately after the centrifuge stopped (10 min). In these samples plasma EPI levels showed a significant reduction compared to the 20 min interval of centrifugation but the EPI levels at 4G-6G were still significantly elevated compared to pre- centrifugation levels. Plasma NE levels showed less pronounced changes (increased after 6G only) with a slower return to control levels.Thus, our data has shown completely different responses of the adrenomedullary (epinephrine) and sympathoneural (norepinephrine) systems to hypergravitation. This data shows that the increased gravitation and not the stressful situations connected with centrifugation is the factor responsible for massive activation of the adrenomedullary system. The mechanism of small activation of the

  5. Influence of the positive prewhirl on the performance of centrifugal pumps with different airfoils

    International Nuclear Information System (INIS)

    Zhou, C M; Wang, H M; Huang, X; Lin, H

    2012-01-01

    According to the basic theory of turbomachinery design and inlet guide vanes prewhirl regulation, two different airfoils inlet guide vanes of prewhirl regulation device were designed, the influence of the positive prewhirl to the performance of centrifugal pump were studied based on different airfoils. The results show that, for a single-suction centrifugal pump: Gottingen bowed blade-type inlet guide vane adjustment effect is better than straight blade-type inlet guide; appropriate design of positive prewhirl can elevate the efficiency of centrifugal pumps. Compared with no vane conditions, the efficiency of centrifugal pump with prewhirl vanes has been greatly improved and the power consumption has been reduced significantly, while has little influence on the head.

  6. Impeller inlet geometry effect on performance improvement for centrifugal pumps

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Xianwu; Zhang, Yao; Peng, Junqi; Xu, Hongyuan [Tsinghua University, Beijing (China); Yu, Weiping [Zhejiang Pump Works, Zhejiang (China)

    2008-10-15

    This research treats the effect of impeller inlet geometry on performance improvement for a boiler feed pump, who is a centrifugal pump having specific speed of 183 m.m{sup 3}min{sup -1}.min{sup -1} and close type impeller with exit diameter of 450 mm. The hydraulic performance and cavitation performance of the pump have been tested experimentally. In order to improve the pump, five impellers have been considered by extending the blade leading edge or applying much larger blade angle at impeller inlet compared with the original impeller. The 3-D turbulent flow inside those pumps has been analyzed basing on RNG k-{epsilon} turbulence model and VOF cavitation model. It is noted that the numerical results are fairly good compared with the experiments. Based on the experimental test and numerical simulation, the following conclusions can be drawn: (1) Impeller inlet geometry has important influence on performance improvement in the case of centrifugal pump. Favorite effects on performance improvement have been achieved by both extending the blade leading edge and applying much larger blade angle at impeller inlet: (2) It is suspected that the extended leading edge have favorite effect for improving hydraulic performance, and the much larger blade angle at impeller inlet have favorite effect for improving cavitation performance for the test pump: (3) Uniform flow upstream of impeller inlet is helpful for improving cavitation performance of the pump

  7. Effect of centrifuge test on blood serum lipids index of cadet pilots.

    Science.gov (United States)

    Wochyński, Zbigniew; Kowalczuk, Krzysztof; Kłossowski, Marek; Sobiech, Krzysztof A

    2016-01-01

    This study aimed at investigating the relationship between the lipid index (WS) in the examined cadets and duration of exposure to +Gz in the human centrifuge. The study involved 19 first-year cadets of the Polish Air Force Academy in Dęblin. Tests in the human centrifuge were repeated twice, i.e. prior to (test I) and 45 days after (test II). After exposure to +Gz, the examined cadets were divided into 2 groups. Group I (N=11) included cadets subjected to a shorter total duration of exposure to +Gz, while group II (N=8) included cadets with a longer total duration of exposure to +Gz. Total cholesterol (TC), high density lipoprotein (HDL), triglycerides (TG), and apolipoproteins A1 and B were assayed in blood serum prior to (assay A) and after (assay B) both exposures to +Gz. Low density lipoprotein (LDL) level was estimated from the Friedewald formula. WS is an own mathematical algorithm. WS was higher in group II, assay A - 10.0 and B - 10.08 of test I in the human centrifuge than in group I where the WS values were 6.91 and 6.96, respectively. WS was also higher in group II in assay A - 10.0 and B -10.1 of test II in the human centrifuge than in group I - 6.96 and 6.80, respectively. The higher value of WS in group II, both after the first and second exposure to +Gz in human centrifuge, in comparison with group I, indicated its usefulness for determination of the maximum capability of applying acceleration of the interval type during training in the human centrifuge.

  8. 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.

  9. Centrifugation protocols: tests to determine optimal lithium heparin and citrate plasma sample quality.

    Science.gov (United States)

    Dimeski, Goce; Solano, Connie; Petroff, Mark K; Hynd, Matthew

    2011-05-01

    Currently, no clear guidelines exist for the most appropriate tests to determine sample quality from centrifugation protocols for plasma sample types with both lithium heparin in gel barrier tubes for biochemistry testing and citrate tubes for coagulation testing. Blood was collected from 14 participants in four lithium heparin and one serum tube with gel barrier. The plasma tubes were centrifuged at four different centrifuge settings and analysed for potassium (K(+)), lactate dehydrogenase (LD), glucose and phosphorus (Pi) at zero time, poststorage at six hours at 21 °C and six days at 2-8°C. At the same time, three citrate tubes were collected and centrifuged at three different centrifuge settings and analysed immediately for prothrombin time/international normalized ratio, activated partial thromboplastin time, derived fibrinogen and surface-activated clotting time (SACT). The biochemistry analytes indicate plasma is less stable than serum. Plasma sample quality is higher with longer centrifugation time, and much higher g force. Blood cells present in the plasma lyse with time or are damaged when transferred in the reaction vessels, causing an increase in the K(+), LD and Pi above outlined limits. The cells remain active and consume glucose even in cold storage. The SACT is the only coagulation parameter that was affected by platelets >10 × 10(9)/L in the citrate plasma. In addition to the platelet count, a limited but sensitive number of assays (K(+), LD, glucose and Pi for biochemistry, and SACT for coagulation) can be used to determine appropriate centrifuge settings to consistently obtain the highest quality lithium heparin and citrate plasma samples. The findings will aid laboratories to balance the need to provide the most accurate results in the best turnaround time.

  10. Review of the gas centrifuge until 1962. Part I: Principles of separation physics

    International Nuclear Information System (INIS)

    Whitley, S.

    1984-01-01

    There are two sets of principles involved in the development of the gas centrifuge, the internal separation physics and the external means of spinning a rotor at very high speeds. Only the first aspect is discussed in this part of the review. First, the industrial requirement for the separation of the uranium isotopes is defined so that the separation history can be put in a modern perspective. The history of separation physics itself is then traced back to the theory of centrifugal force by Huygens and the equivalence of this force to that of gravity. The barometric equation giving the variation of atmospheric pressure with height and the law of partial pressures can then be adapted to the centrifuge to give the steady-state theory of separation. This work was completed in the last century but was not confirmed in its application to isotope separation until 1936. The detailed separation physics for non-steady-state conditions required for a production centrifuge was developed during the American wartime Manhattan Project. During this work the theory giving the maximum output of a centrifuge was developed by Dirac, and soon afterwards Cohen and Kaplan showed that the best method of operation for a production centrifuge is in a countercurrent mode of operation. This method gives a large separation factor at relatively small flow rates through the rotor. The theory of how to set up an internal countercurrent was given by Martin during an equivalent wartime German project, and refinements to the theory, showing how the countercurrent persists along a centrifuge rotor, was given by Dirac and Steenbeck, the latter during a postwar Russian project. This theory was extended by Parker, Ging, and Mayo of the University of Virginia, whose work was completed by 1962, the limit of this review

  11. Effect of centrifugation on dynamic susceptibility of magnetic fluids

    Science.gov (United States)

    Pshenichnikov, Alexander; Lebedev, Alexander; Lakhtina, Ekaterina; Kuznetsov, Andrey

    2017-06-01

    The dispersive composition, dynamic susceptibility and spectrum of times of magnetization relaxation for six samples of magnetic fluid obtained by centrifuging two base colloidal solutions of the magnetite in kerosene was investigated experimentally. The base solutions differed by the concentration of the magnetic phase and the width of the particle size distribution. The procedure of cluster analysis allowing one to estimate the characteristic sizes of aggregates with uncompensated magnetic moments was described. The results of the magnetogranulometric and cluster analyses were discussed. It was shown that centrifugation has a strong effect on the physical properties of the separated fractions, which is related to the spatial redistribution of particles and multi-particle aggregates. The presence of aggregates in magnetic fluids is interpreted as the main reason of low-frequency (0.1-10 kHz) dispersion of the dynamic susceptibility. The obtained results count in favor of using centrifugation as an effective means of changing the dynamic susceptibility over wide limits and obtaining fluids with the specified type of susceptibility dispersion.

  12. Sustained Accelerated Idioventricular Rhythm in a Centrifuge-Simulated Suborbital Spaceflight.

    Science.gov (United States)

    Suresh, Rahul; Blue, Rebecca S; Mathers, Charles; Castleberry, Tarah L; Vanderploeg, James M

    2017-08-01

    Hypergravitational exposures during human centrifugation are known to provoke dysrhythmias, including sinus dysrhythmias/tachycardias, premature atrial/ventricular contractions, and even atrial fibrillations or flutter patterns. However, events are generally short-lived and resolve rapidly after cessation of acceleration. This case report describes a prolonged ectopic ventricular rhythm in response to high G exposure. A previously healthy 30-yr-old man voluntarily participated in centrifuge trials as a part of a larger study, experiencing a total of 7 centrifuge runs over 48 h. Day 1 consisted of two +Gz runs (peak +3.5 Gz, run 2) and two +Gx runs (peak +6.0 Gx, run 4). Day 2 consisted of three runs approximating suborbital spaceflight profiles (combined +Gx and +Gz). Hemodynamic data collected included blood pressure, heart rate, and continuous three-lead electrocardiogram. Following the final acceleration exposure of the last Day 2 run (peak +4.5 Gx and +4.0 Gz combined, resultant +6.0 G), during a period of idle resting centrifuge activity (resultant vector +1.4 G), the subject demonstrated a marked change in his three-lead electrocardiogram from normal sinus rhythm to a wide-complex ectopic ventricular rhythm at a rate of 91-95 bpm, consistent with an accelerated idioventricular rhythm (AIVR). This rhythm was sustained for 2 m, 24 s before reversion to normal sinus. The subject reported no adverse symptoms during this time. While prolonged, the dysrhythmia was asymptomatic and self-limited. AIVR is likely a physiological response to acceleration and can be managed conservatively. Vigilance is needed to ensure that AIVR is correctly distinguished from other, malignant rhythms to avoid inappropriate treatment and negative operational impacts.Suresh R, Blue RS, Mathers C, Castleberry TL, Vanderploeg JM. Sustained accelerated idioventricular rhythm in a centrifuge-simulated suborbital spaceflight. Aerosp Med Hum Perform. 2017; 88(8):789-793.

  13. Inertial shear forces and the use of centrifuges in gravity research. What is the proper control?

    NARCIS (Netherlands)

    Loon, van J.J.W.A.; Folgering, H.T.E.; Bouten, C.V.C.; Veldhuijzen, J.P.; Smit, T.H.

    2003-01-01

    Centrifuges are used for 1×g controls in space flight microgravity experiments and in ground based research. Using centrifugation as a tool to generate an Earth like acceleration introduces unwanted inertial shear forces to the sample. Depending on the centrifuge and the geometry of the experiment

  14. 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

  15. Design Method for Channel Diffusers of Centrifugal Compressors

    Directory of Open Access Journals (Sweden)

    Mykola Kalinkevych

    2013-01-01

    Full Text Available The design method for channel diffusers of centrifugal compressors, which is based on the solving of the inverse problem of gas dynamics, is presented in the paper. The concept of the design is to provide high pressure recovery of the diffuser by assuming the preseparation condition of the boundary layer along one of the channel surfaces. The channel diffuser was designed with the use of developed method to replace the vaned diffuser of the centrifugal compressor model stage. The numerical simulation of the diffusers was implemented by means of CFD software. Obtained gas dynamic characteristics of the designed diffuser were compared to the base vaned diffuser of the compressor stage.

  16. Centrifuge pellet injector for JET

    International Nuclear Information System (INIS)

    Andelfinger, C.; Buchelt, E.; Jacobi, D.; Lackner, E.; Schilling, H.B.; Ulrich, M.; Weber, G.

    1983-08-01

    An engineering design of a centrifuge pellet injector for JET is reported as part of the Phase I contract number JE 2/9016. A rather detailed design is presented for the mechanical and electronic features. Stress calculations, dynamic behaviour and life estimates are considered. The interfaces to the JET vacuum system and CODAS are discussed. Proposals for the pellet diagnostics (velocity, mass and shape) are presented. (orig.)

  17. 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.

  18. 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.

  19. A high pressure centrifugal oxygen compressor

    International Nuclear Information System (INIS)

    Larsen, L.P.

    1986-01-01

    The application of a centrifugal compressor train to 5860 kPa(g) (850 psig) for a coal gasification plant is discussed. Special considerations in the application, installation, and operation of the equipment are presented. Discussion includes such topics as compressor controls, machinery protection, noise, personnel safety, and operation of the equipment

  20. Evolutionary Optimization of Centrifugal Nozzles for Organic Vapours

    Science.gov (United States)

    Persico, Giacomo

    2017-03-01

    This paper discusses the shape-optimization of non-conventional centrifugal turbine nozzles for Organic Rankine Cycle applications. The optimal aerodynamic design is supported by the use of a non-intrusive, gradient-free technique specifically developed for shape optimization of turbomachinery profiles. The method is constructed as a combination of a geometrical parametrization technique based on B-Splines, a high-fidelity and experimentally validated Computational Fluid Dynamic solver, and a surrogate-based evolutionary algorithm. The non-ideal gas behaviour featuring the flow of organic fluids in the cascades of interest is introduced via a look-up-table approach, which is rigorously applied throughout the whole optimization process. Two transonic centrifugal nozzles are considered, featuring very different loading and radial extension. The use of a systematic and automatic design method to such a non-conventional configuration highlights the character of centrifugal cascades; the blades require a specific and non-trivial definition of the shape, especially in the rear part, to avoid the onset of shock waves. It is shown that the optimization acts in similar way for the two cascades, identifying an optimal curvature of the blade that both provides a relevant increase of cascade performance and a reduction of downstream gradients.

  1. Simplified simulation of multicomponent isotope separation by gas centrifuge

    International Nuclear Information System (INIS)

    Guo Zhixiong; Ying Chuntong

    1995-01-01

    The expressions of diffusion equation for multicomponent isotope separation by gas centrifuge are derived by utilizing the simplified diffusion transport vector. A method of radial averaging which was restricted to a binary mixture is extended to multicomponent isotope mixtures by using an iterative scheme. A numerical analysis of tetradic UF 6 or SF 6 gas isotope separation by centrifuge is discussed when a special model of velocity distribution is given. The dependence of mutual separation factor for the components on their molecular weights' difference is obtained. Some aspects of the given model of gas fluid are also discussed

  2. Gas-centrifuge unit and centrifugal process for isotope separation

    International Nuclear Information System (INIS)

    Stark, T.M.

    1979-01-01

    An invention involving a process and apparatus for isotope-separation applications such as uranium-isotope enrichment is disclosed which employs cascades of gas centrifuges. A preferred apparatus relates to an isotope-enrichment unit which includes a first group of cascades of gas centrifuges and an auxiliary cascade. Each cascade has an input, a light-fraction output, and a heavy-fraction output for separating a gaseous-mixture feed including a compound of a light nuclear isotope and a compound of a heavy nuclear isotope into light and heavy fractions respectively enriched and depleted in the light isotope. The cascades of the first group have at least one enriching stage and at least one stripping stage. The unit further includes means for introducing a gaseous-mixture feedstock into each input of the first group of cascades, means for withdrawing at least a portion of a product fraction from the light-fraction outputs of the first group of cascades, and means for withdrawing at least a portion of a waste fraction from the heavy-fraction outputs of the first group of cascades. The isotope-enrichment unit also includes a means for conveying a gaseous-mixture from a light-fraction output of a first cascade included in the first group to the input of the auxiliary cascade so that at least a portion of a light gaseous-mixture fraction produced by the first group of cascades is further separated into a light and a heavy fraction by the auxiliary cascade. At least a portion of a product fraction is withdrawn from the light fraction output of the auxiliary cascade. If the light-fraction output of the first cascade and the heavy-fraction output of the auxiliary cascade are reciprocal outputs, the concentraton of the light isotope in the heavy fraction produced by the auxiliary cascade essentially equals the concentration of the light isotope in the gaseous-mixture feedstock

  3. LMR [liquid metal reactor] centrifugal pump coastdowns

    International Nuclear Information System (INIS)

    Dunn, F.E.; Malloy, D.J.

    1987-01-01

    A centrifugal pump model which describes the interrelationships of the pump discharge flowrate, pump speed, shaft torque and dynamic head has been implemented based upon existing models. Specifically, the pump model is based upon the dimensionless-homologous pump theory of Wylie and Streeter. Given data from a representative pump, homologous theory allows one to predict the transient characteristics of similarly sized pumps. This homologous pump model has been implemented into both the one-dimensional SASSYS-1 systems analysis code and the three-dimensional COMMIX-1A code. Comparisons have been made both against other pump models (CRBR) and actual pump coastdown data (EBR-II and FFTF). Agreement with this homologous pump model has been excellent. Additionally, these comparisons indicate the validity of applying the medium size pump data of Wylie and Streeter to a range of typical LMR centrifugal pumps

  4. Reverse-Tangent Injection in a Centrifugal Compressor

    Science.gov (United States)

    Skoch, Gary J.

    2007-01-01

    Injection of working fluid into a centrifugal compressor in the reverse tangent direction has been invented as a way of preventing flow instabilities (stall and surge) or restoring stability when stall or surge has already commenced. The invention applies, in particular, to a centrifugal compressor, the diffuser of which contains vanes that divide the flow into channels oriented partly radially and partly tangentially. In reverse-tangent injection, a stream or jet of the working fluid (the fluid that is compressed) is injected into the vaneless annular region between the blades of the impeller and the vanes of the diffuser. As used here, "reverse" signifies that the injected flow opposes (and thereby reduces) the tangential component of the velocity of the impeller discharge. At the same time, the injected jet acts to increase the radial component of the velocity of the impeller discharge.

  5. Steady state behavior of rotating plasmas in a vacuum-arc centrifuge

    International Nuclear Information System (INIS)

    Bittencourt, J.A.; Ludwig, G.O.

    1987-01-01

    The steady state behaviour of the fully ionized, multiple species, rotating, magnetized plasma in a vacuum-arc plasma centrifuge is described in detail. The analysis is based on a multiple species fluid model which includes electromagnetic, pressure gradient, centrifugal and collisional forces, for each species, in cylindrical geometry. It is shown that there is a family of theoretically possible dynamical equilibrium configurations, which can be achieved by different combinations of ion rotation velocity, radial ion density distribution and radial dependence of internal electric potential. The parametric dependences of the various plasma parameters under equilibrium conditions, including the ion separation factor, are presented for a nickel-copper plasma. The numerical results are analysed and discussed in light of experimentally measured plasma characteristics in a vacuum-arc plasma centrifuge. (author)

  6. Steady state behavior of rotating plasmas in a vacuum-arc centrifuge

    International Nuclear Information System (INIS)

    Bittencourt, J.A.; Ludwig, G.O.

    1986-06-01

    The steady state behavior of the fully ionized, multiple species, rotating, magnetized plasma in a vacuum-arc plasma centrifuge is described in detail. The analysis is based on a multiple species fluid model which includes electromagnetic, pressure gradient, centrifugal and collisional forces, for each species, in cylindrical geometry. It is showm that there is a family of theoretically possible dynamical equilibrium configurations, which can be achieved by different combinations of ion rotation velocity, radial ion density distribution and radial dependence of internal electric potential. The parametric dependences of the various plasma parameters under equilibrium conditions, including the ion separation factor, are presented for a nickel-copper plasma. The numerical results are analysed and discussed on light of experimentally measured plasma characteristics in a vacuum-arc plasma centrifuge. (Author) [pt

  7. Impeller radial force evolution in a large double-suction centrifugal pump during startup at the shut-off condition

    International Nuclear Information System (INIS)

    Zou, Zhichao; Wang, Fujun; Yao, Zhifeng; Tao, Ran; Xiao, Ruofu; Li, Huaicheng

    2016-01-01

    Highlights: • Conclude the characteristics of transient radial force in the startup process for a large double-suction centrifugal pump. • The overall direction of the radial force during startup process is also confirmed. • A formula used to calculate the transient radial force during startup process is proposed. • A relationship between radial force variation and axial vortex development in blade channel during the startup process is established. The mechanism of the radial force evolution is revealed. - Abstract: Double-suction centrifugal pumps play an important role in the main feedwater systems of nuclear power plant. The impeller radial force in a centrifugal pump varies dramatically during startup at the shut-off condition. In this study, the startup process of a large double-suction centrifugal pump is investigated using CFD. During testing, the impeller speed is accelerated from zero to its rated speed in 1.0 s (marked as t_0) and is then maintained at the rated speed. The results show that the radial force increase lags behind the impeller speed increase. At 0–0.4t_0, the radial force is small (approaching zero). At 0.4–1.4t_0, the radial force increases rapidly. After 1.4t_0, the average radial force stabilizes and reaches its maximum value of 55,619 N. The observed maximum radial force value during startup is approximately nine times as high as the radial force under rated condition. During startup, the overall radial force direction is proximate to the radial line located 25° from the volute tongue along circumferential direction. A transient radial force formula is proposed to evaluate the changes in radial force during startup. The streamline distribution in impeller passages and the impeller outlet pressure profile varying over time are produced. The relationship between radial force evolution and the varying axial-to-spiral vortex structure is analyzed. The radial force change mechanism is revealed. This research provides a scientific

  8. Impeller radial force evolution in a large double-suction centrifugal pump during startup at the shut-off condition

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Zhichao [College of Water Resources and Civil Engineering, China Agricultural University, Beijing 100083 (China); Wang, Fujun, E-mail: wangfj@cau.edu.cn [College of Water Resources and Civil Engineering, China Agricultural University, Beijing 100083 (China); Beijing Engineering Research Center of Safety and Energy Saving Technology for Water Supply Network System, China Agricultural University, Beijing 100083 (China); Yao, Zhifeng [College of Water Resources and Civil Engineering, China Agricultural University, Beijing 100083 (China); Beijing Engineering Research Center of Safety and Energy Saving Technology for Water Supply Network System, China Agricultural University, Beijing 100083 (China); Tao, Ran [College of Water Resources and Civil Engineering, China Agricultural University, Beijing 100083 (China); Xiao, Ruofu [College of Water Resources and Civil Engineering, China Agricultural University, Beijing 100083 (China); Beijing Engineering Research Center of Safety and Energy Saving Technology for Water Supply Network System, China Agricultural University, Beijing 100083 (China); Li, Huaicheng [Shanghai Liancheng (Group) Co., Ltd., Shanghai 201812 (China)

    2016-12-15

    Highlights: • Conclude the characteristics of transient radial force in the startup process for a large double-suction centrifugal pump. • The overall direction of the radial force during startup process is also confirmed. • A formula used to calculate the transient radial force during startup process is proposed. • A relationship between radial force variation and axial vortex development in blade channel during the startup process is established. The mechanism of the radial force evolution is revealed. - Abstract: Double-suction centrifugal pumps play an important role in the main feedwater systems of nuclear power plant. The impeller radial force in a centrifugal pump varies dramatically during startup at the shut-off condition. In this study, the startup process of a large double-suction centrifugal pump is investigated using CFD. During testing, the impeller speed is accelerated from zero to its rated speed in 1.0 s (marked as t{sub 0}) and is then maintained at the rated speed. The results show that the radial force increase lags behind the impeller speed increase. At 0–0.4t{sub 0}, the radial force is small (approaching zero). At 0.4–1.4t{sub 0}, the radial force increases rapidly. After 1.4t{sub 0}, the average radial force stabilizes and reaches its maximum value of 55,619 N. The observed maximum radial force value during startup is approximately nine times as high as the radial force under rated condition. During startup, the overall radial force direction is proximate to the radial line located 25° from the volute tongue along circumferential direction. A transient radial force formula is proposed to evaluate the changes in radial force during startup. The streamline distribution in impeller passages and the impeller outlet pressure profile varying over time are produced. The relationship between radial force evolution and the varying axial-to-spiral vortex structure is analyzed. The radial force change mechanism is revealed. This research

  9. Combined short-arm centrifuge and aerobic exercise training improves cardiovascular function and physical working capacity in humans.

    Science.gov (United States)

    Yang, Chang-Bin; Zhang, Shu; Zhang, Yu; Wang, Bing; Yao, Yong-Jie; Wang, Yong-Chun; Wu, Yan-Hong; Liang, Wen-Bin; Sun, Xi-Qing

    2010-12-01

    Musculoskeletal and cardiovascular deconditioning occurring in long-term spaceflight gives rise to the needs to develop new strategies to counteract these adverse effects. Short-arm centrifuge combined with ergometer has been proposed as a strategy to counteract adverse effects of microgravity. This study sought to investigate whether the combination of short-arm centrifuge and aerobic exercise training have advantages over short-arm centrifuge or aerobic exercise training alone. One week training was conducted by 24 healthy men. They were randomly divided into 3 groups: (1) short-arm centrifuge training, (2) aerobic exercise training, 40 W, and (3) combined short-arm centrifuge and aerobic exercise training. Before and after training, the cardiac pump function represented by stroke volume, cardiac output, left ventricular ejection time, and total peripheral resistance was evaluated. Variability of heart rate and systolic blood pressure were determined by spectral analysis. Physical working capacity was surveyed by near maximal physical working capacity test. The 1-week combined short-arm centrifuge and aerobic exercise training remarkably ameliorated the cardiac pump function and enhanced vasomotor sympathetic nerve modulation and improved physical working capacity by 10.9% (Pcentrifuge nor the aerobic exercise group showed improvements in these functions. These results demonstrate that combined short-arm centrifuge and aerobic exercise training has advantages over short-arm centrifuge or aerobic exercise training alone in influencing several physiologically important cardiovascular functions in humans. The combination of short-arm centrifuge and aerobic exercise offers a promising countermeasure to microgravity.

  10. 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 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 (centrifuge needs to be operated, reducing the need for repeated pilot-scale runs during early stages of process development. Copyright © 2012 Wiley Periodicals, Inc.

  11. An Optimal Design Method of Centrifugal Compressors in Consideration of the Efficiency and the Noise

    International Nuclear Information System (INIS)

    Ha, K. G.; Sung, S. M.; Kang, S. H.

    2007-01-01

    A centrifugal compressor is a principal part of the fuelcell vehicles, aircraft and home appliances. Therefore not only efficiency but also compact size and a low operation RPM for noise reducing turn into important criteria of centrifugal compressors design. But those criteria are in conflict each other often. In the case of a RPM in particular, it is profitable to lower the RPM for a noise reduction and an endurance. But for a compact size and a light weight, the reverse has a beneficial effect undoubtedly. So it is necessary to introduce a new optimization concept in the centrifugal compressor design. An one dimensional optimal design method for the centrifugal compressor considering a impeller, a vaneless diffuser and a volute at a time is described. The new optimization process and underlying design methods of centrifugal compressors and some optimal design results are included in the paper

  12. Tuberculosis diagnosis and multidrug resistance testing by direct sputum culture in selective broth without decontamination or centrifugation.

    Science.gov (United States)

    Grandjean, Louis; Martin, Laura; Gilman, Robert H; Valencia, Teresa; Herrera, Beatriz; Quino, Willi; Ramos, Eric; Rivero, Maribel; Montoya, Rosario; Escombe, A Roderick; Coleman, David; Mitchison, Denis; Evans, Carlton A

    2008-07-01

    Tuberculosis culture usually requires sputum decontamination and centrifugation to prevent cultures from being overgrown by contaminating bacteria and fungi. However, decontamination destroys many tuberculous bacilli, and centrifugation often is not possible in resource-poor settings. We therefore assessed the performance of Mycobacterium tuberculosis culture with unprocessed samples plated directly by using tuberculosis-selective media and compared this procedure to conventional culture using centrifuge decontamination. Quadruplicate aliquots of strain H37RV were cultured in 7H9 broth with and without selective antimicrobials and after centrifuge decontamination. The subsequent comparison was made with 715 sputum samples. Split paired sputum samples were cultured conventionally with centrifuge decontamination and by direct culture in tuberculosis-selective media containing antibiotics. Centrifuge decontamination reduced tuberculosis H37RV colonies by 78% (P laboratories this deficit may be outweighed by the ease of use.

  13. New improved counter - current multi-stage centrifugal extractor for solvent extraction process

    International Nuclear Information System (INIS)

    Gheorghe, Ionita; Mirica, Dumitru; Croitoru, Cornelia; Stefanescu, Ioan; Retegan, Teodora; Kitamoto, Asashi

    2003-01-01

    Total actinide recovery, lanthanide/actinide separation and selective partitioning of actinide from high level waste (HLW) are nowadays of a major interest. Actinide partitioning with a view to safe disposing of HLW or utilization in many other applications of recovered elements involves an extraction process usually by means of mixer-settler, pulse column or centrifugal contactor. The latter, presents some doubtless advantages and responds to the above mentioned goals. A new type of counter-current multistage centrifugal extractor has been designed and performed. A similar apparatus was not found from in other published papers as yet. The counter-current multi-stage centrifugal extractor was a cylinder made of stainless steel with an effective length of 346 mm, the effective diameter of 100 mm and a volume of 1.5 liters, working in a horizontal position. The new internal structure and geometry of the new advanced centrifugal extractor consisting of nine cells (units), five rotation units, two mixing units, two propelling units and two final plates, ensures the counter-current running of the two phases.The central shaft having the rotation cells fixed on it is coupled by an intermediary connection to a electric motor of high rotation speed. The conceptual layout of the advanced counter-current multi-stage centrifugal extractor is presented. The newly designed extractor has been tested at 500-2800 rot/min for a ratio of the aqueous/organic phase =1 to examine the mechanical behavior and the hydrodynamics of the two phases in countercurrent. The results showed that the performances have been generally good and the design requirements were fulfilled. The newly designed counter-current multistage centrifugal extractor appears to be a promising way to increase extraction rate of radionuclides and metals from liquid effluents. (authors)

  14. 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. 864.9275 Section 864.9275 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Manufacture Blood and Blood Products § 864.9275 Blood bank centrifuge for in vitro diagnostic use. (a...

  15. A Numerical Study of the Impact of Radial Baffles in solid Bowl Centrifuges Using computational Fluid Dynamics

    OpenAIRE

    Romani, Xiana; Nirschl, Hermann

    2010-01-01

    Centrifugal separation equipment, such as solid bowl centrifuges, is used to carry out an effective separation of fine particles from industrial fluids. Knowledge of the streams and sedimentation behavior inside solid bowl centrifuges is necessary to determine the geometry and the process parameters that lead to an optimal performance. Regarding a given industrial centrifuge geometry, a grid was built to calculate numerically the multiphase flow of water, air, and particles with a computation...

  16. Centrifuge Techniques and Apparatus for Transport Experiments in Porous Media

    Energy Technology Data Exchange (ETDEWEB)

    Earl D. Mattson; Carl D. Paler; Robert W. Smith; Markus Flury

    2010-06-01

    This paper describes experimental approaches and apparatus that we have developed to study solute and colloid transport in porous media using Idaho National Laboratory's 2-m radius centrifuge. The ex-perimental techniques include water flux scaling with applied acceleration at the top of the column and sub-atmospheric pressure control at the column base, automation of data collection, and remote experimental con-trol over the internet. These apparatus include a constant displacement piston pump, a custom designed liquid fraction collector based on switching valve technology, and modified moisture monitoring equipment. Suc-cessful development of these experimental techniques and equipment is illustrated through application to transport of a conservative tracer through unsaturated sand column, with centrifugal acceleration up to 40 gs. Development of such experimental equipment that can withstand high accelerations enhances the centrifuge technique to conduct highly controlled unsaturated solute/colloid transport experiments and allows in-flight liquid sample collection of the effluent.

  17. Evaluation of amides and centrifugation temperature in boar semen cryopreservation.

    Science.gov (United States)

    Bianchi, I; Calderam, K; Maschio, E F; Madeira, E M; da Rosa Ulguim, R; Corcini, C D; Bongalhardo, D C; Corrêa, E K; Lucia, T; Deschamps, J C; Corrêa, M N

    2008-03-15

    Two experiments were conducted to evaluate the use of amides as cryoprotectants and two centrifugation temperatures (15 or 24 degrees C) in boar semen cryopreservation protocols. Semen was diluted in BTS, cooled centrifuged, added to cooling extenders, followed by the addition of various cryoprotectants. In experiment 1, mean (+/-S.E.M.) sperm motility for 5% dimethylformamide (DMF; 50.6+/-1.9%) and 5% dimethylacetamide (DMA; 53.8+/-1.7%) were superior (P0.05). In experiment 2, we tested MF, DMF, and DMA at 3, 5, and 7%. Sperm motility and membrane integrity were higher for 5% DMA (53.8+/-1.7 and 50.9+/-1.9%) and 5% DMF (50.6+/-1.9 and 47.9+/-2.1%), in comparison with 7% DMF and all MF concentrations (P0.05). In conclusion, boar semen was successfully cryopreserved by replacement of glycerol with amides (especially 5% DMA) and centrifugation at 15 degrees C, with benefits for post-thaw sperm motility and membrane integrity.

  18. Centrifuge model test of rock slope failure caused by seismic excitation. Applicability to the stability evaluation method of safety factors against sliding

    International Nuclear Information System (INIS)

    Ishimaru, Makoto; Kawai, Tadashi

    2010-01-01

    The purposes of this study are to analyze dynamic failure characteristics of slopes in discontinuous rock mass with brittle fracture by centrifuge model tests and to study applicability to the equivalent linear analysis against dynamic sliding failure of rock slopes. We conducted centrifuge model test using a dip slope model with discontinuities imitated by Teflon sheets. The centrifugal acceleration was 30G, and the acceleration amplitudes of input sin waves were increased gradually at every step. The test results were compared with safety factors of the sliding surface based on the equivalent linear analysis. The following results were obtained: (1) The slope model collapsed when it was excited by the sine wave of 350gal, which was converted to real field scale. (2) Artificial discontinuities considerably affected the collapse, and the type of collapse was plane failure. (3) From response displacement records measured at the slope model, the failure around toe of the slope model probably caused the collapse. (4) The evaluation of safety factors against sliding based on the equivalent linear analysis were conservative compared with the experimental results. (author)

  19. 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.

  20. Enrichment technology. Dependable vendor of gas centrifuges; Enrichment Technology. Zuverlaessiger Lieferant von Gaszentrifugen

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2011-10-15

    Enrichment Technology is an innovative, high-tech company that develops, manufactures and installs gas centrifuges for enriching uranium. In addition, Enrichment Technology designs enrichment plants that use gas centrifuge technology. This technology offers the most efficient and cost-effective method for enriching uranium yet: high-performance, safe technology that dominates the market with a global share of 45 percent. A determining factor in Enrichment Technology's success is its mission: supplying its customers with safe, reliable technology. Production of the centrifuges requires versatile know-how and collaboration between different departments as well as interdisciplinary teams at the various sites. More than 2000 operators at 8 sites in 5 countries contribute their individual knowledge and personal skills in order to produce this exceptional technology. The head office is in Beaconsfield near London and the operational headquarters are in Almelo in the Netherlands. There are other sites in Germany (Juelich und Gronau), Great Britain (Capenhurst) as well as project sites in the USA and France. Capenhurst is where experienced engineers design new enrichment plants and organise their construction. Centrifuge components are manufactured in Almelo and Juelich, while the pipework needed to connect up the centrifuges is produced at the site in Gronau. In Juelich, highly qualified scientists in interdisciplinary teams are continuously researching ways of improving the current centrifuges. Communication between specialists in the fields of chemistry, physics and engineering forms the basis for the company's success and the key to extending this leading position in the global enrichment market. (orig.)