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Sample records for centrifugal force

  1. [Galileo and centrifugal force].

    Vilain, Christiane

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

  2. Centrifuges and inertial shear forces

    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

  3. Forces on Centrifugal Pump Impellers

    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. Centrifugal force: a few surprises

    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)

  5. Unexpected properties of the centrifugal force

    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

  6. Unexpected properties of the centrifugal force

    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

  7. Rotordynamic Forces on Centrifugal Pump Impellers

    Franz, R.; Arndt, N.; Caughey, T. K.; Brennen, C. E.; Acosta, A. J.

    1987-01-01

    The asymmetric flow around an impeller in a volute exerts a force upon the impeller. To study the rotordynamic force on an impeller which is vibrating around its machine axis of rotation, the impeller, mounted on a dynamometer, is made to whirl in a circular orbit within the volute. The measured force is expressed as the sum of a steady radial force and an unsteady force due to the eccentric motion of the impeller. These forces were measured in separate tests on a centrifugal pump with rad...

  8. Axial forces in centrifugal compressor couplings

    Ivanov, A. N.; Ivanov, N. M.; Yun, V. K.

    2017-08-01

    The article presents the results of the theoretical and experimental investigation of axial forces arising in the toothed and plate couplings of centrifugal compressor shaft lines. Additional loads on the thrust bearing are considered that can develop in the toothed couplings as a result of coupled rotors misalignment. Design relationships to evaluate the level of axial forces and recommendations for their reduction in the operating conditions are given.

  9. CENTRIFUGE

    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.

  10. Multiplexed single-molecule force spectroscopy using a centrifuge.

    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.

  11. Massively Parallel Single-Molecule Manipulation Using Centrifugal Force

    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.

  12. Origins of hydrodynamic forces on centrifugal pump impellers

    Adkins, Douglas R.; Brennen, Christopher E.

    1987-01-01

    Hydrodynamic interactions that occur between a centrifugal pump impeller and volute are experimentally and theoretically investigated. The theoretical analysis considers the inability of the blades to perfectly guide the flow through the impeller, and also includes a quasi-one dimensional treatment of the flow in the volute. The disturbance at the impeller discharge and the resulting forces are determined by the theoretical model. The model is then extended to obtain the hydrodynamic force perturbations that are caused by the impeller whirling eccentrically in the volute. Under many operating conditions, these force perturbations were found to be destablizing. Comparisons are made between the theoretical model and the experimental measurements of pressure distributions and radial forces on the impeller. The theoretical model yields fairly accurate predictions of the radial forces caused by the flow through the impeller. However, it was found that the pressure acting on the front shroud of the impeller has a substantial effect on the destablizing hydrodynamic forces.

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

    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.

  14. Product Evaluation Task Force Phase Two report for centrifuge cake

    Francis, A.J.; Davies, A.

    1990-01-01

    It has been proposed that all Intermediate Level Wastes arising at Sellafield should be encapsulated prior to ultimate disposal. The Product Evaluation Task Force (PETF) was set up to investigate possible encapsulants and to produce and adequate data base to justify the preferred matrices. Three possible types of encapsulants for Centrifuge Cake;- Inorganic cements, Polymer cements, and Polymers, are evaluated using the Kepner Tregoe decision analysis technique. This technique provides a methodology for scoring and ranking alternative options and evaluating any risks associated with an option. The analysis shows that for all four stages of waste management operations ie. Storage Transport, handling and emplacement Disposal, and Process, cement matrices are considerably superior to other potential matrices. A matrix, consisting of nine parts Blast Furnace Slag (BFS) to one part Ordinary Portland Cement (OPC) is recommended as the preferred matrix for Phase 3 studies on Centrifuge Cake. (author)

  15. Inertial shear forces and the use of centrifuges in gravity research. What is the proper control?

    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

  16. Cancellation of the centrifugal space-charge force

    Lee, E.P.

    1990-01-01

    The transverse dynamics of high-energy electrons confined in curved geometry are examined, including the effects of space-charge-induced fields. Attention is restricted to the centrifugal-space-charge force, which is the result of noncancellation of beam-induced transverse electric and magnetic fields in the curved geometry. This force is shown to be nearly cancelled in the evaluation of the horizontal tune and chromaticity by another, often overlooked term in the equation of motion. The additional term is the consequence of oscillations of the kinetic energy, which accompany betatron oscillations in the beam-induced electric potential. In curved geometry this term is of first order in the amplitude of the radial oscillation. A highly simplified system model is employed so that physical effects appear in as clear a form as possible. We assume azimuthal and median plane symmetry, static fields, and ultrarelativistic particle velocity (1/γ 2 ->0). (author) 9 refs

  17. Centrifugation

    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

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

    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.

  19. Influence of impeller and diffuser geometries on the lateral fluid forces of whirling centrifugal impeller

    Ohashi, Hideo; Sakurai, Akira; Nishihama, Jiro

    1989-01-01

    Lateral fluid forces on two-dimensional centrifugal impellers, which whirl on a circular orbit in a vaneless diffuser, were reported. Experiments were further conducted for the cases in which a three-dimensional centrifugal impeller, a model of the boiler feed pump, whirls in vaneless and vaned diffusers. The influence of the clearance configuration between the casing and front shroud of the impeller was also investigated. The result indicated that the fluid dynamic interaction between the impeller and the guide vanes induces quite strong fluctuating fluid forces to the impeller, but nevertheless its influence on radial and tangential force components averaged over a whirling orbit is relatively small.

  20. Huygens' principle, the free Schrodinger particle and the quantum anti-centrifugal force

    Cirone, M.A.; Dahl, Jens Peder; Fedorov, M.

    2002-01-01

    Huygens' principle following from the d'Alembert wave equation is not valid in two-dimensional space. A Schrodinger particle of vanishing angular momentum moving freely in two dimensions experiences an attractive force-the quantum anti-centrifugal force-towards its centre. We connect these two...

  1. Numerical analysis on the action of centrifuge force in magnetic fluid rotating shaft seals

    Zou, Jibin; Li, Xuehui; Lu, Yongping; Hu, Jianhui

    2002-11-01

    The magnetic fluid seal is suitable for high-speed rotating shaft seal applications. Centrifuge force will have evident influence on magnetic fluid rotating shaft seals. The seal capacity of the rotating shaft seal can be improved or increased by some measures. Through hydrodynamic analysis the moving status of the magnetic fluid is worked out. By numerical method, the magnetic field and the isobars in the magnetic fluid of a seal device are computed. Then the influence of the centrifuge force on the magnetic fluid seal is calculated quantitatively.

  2. Numerical analysis on the action of centrifuge force in magnetic fluid rotating shaft seals

    Zou Jibin; Li Xuehui; Lu Yongping; Hu Jianhui

    2002-01-01

    The magnetic fluid seal is suitable for high-speed rotating shaft seal applications. Centrifuge force will have evident influence on magnetic fluid rotating shaft seals. The seal capacity of the rotating shaft seal can be improved or increased by some measures. Through hydrodynamic analysis the moving status of the magnetic fluid is worked out. By numerical method, the magnetic field and the isobars in the magnetic fluid of a seal device are computed. Then the influence of the centrifuge force on the magnetic fluid seal is calculated quantitatively

  3. A novel centrifuge for animal physiological researches in hypergravity and variable gravity forces

    Kumei, Yasuhiro; Hasegawa, Katsuya; Inoue, Katarzyna; Zeredo, . Jorge; Kimiya Narikiyo, .; Maezawa, Yukio; Yuuki Watanabe, .; Aou, Shuji

    2012-07-01

    Understanding the physiological responses to altered gravitational environments is essential for space exploration and long-term human life in space. Currently available centrifuges restrict experimentation due to limited space for laboratory equipments. We developed a medium-sized disc-type centrifuge to conduct ground-based studies on animal physiological response to hypergravity and variable gravity forces, which features the following advantages: 1) It enables simultaneous examination into the effects of various gravity levels including rotation control. 2) Beside the constant G force, variable G forces (delta-G) can be loaded to generate gravitational acceleration and deceleration. 3) Multiple imaging techniques can be used, such as high-speed video (16 channels wireless) and photography, X-ray, and infra-red imaging. 4) Telemetry is available on the disc table of the centrifuge through 128-channel analog and 32-channel digital signals, with sampling rate of 100 kHz for 2 hours. Our dynamic-balanced centrifuge can hold payloads of 600 kg that enable experimentation on various models of living organisms, from cells to animals and plants. We use this novel centrifuge for neurochemical and neurophysiological approaches such as microdialysis and telemetrical recording of neuronal activity in the rat brain. Financial supports from JSPS to K. Hasegawa (2011) and from JAXA to Y. Kumei (2011).

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

    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.

  5. Optimizing platelet-rich plasma gel formation by varying time and gravitational forces during centrifugation.

    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.

  6. Effect of Perturbations in the Coriolis and Centrifugal Forces on the ...

    body problem (R3BP) when small perturbations are conferred to the centrifugal and Coriolis forces. It is found that the position and stability of the triangular point are affected by both the relativistic factor and small perturbations in the Coriolis and ...

  7. 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.

    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.

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

    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.

  9. Centrifugal Force Based Magnetic Micro-Pump Driven by Rotating Magnetic Fields

    Kim, S H; Hashi, S; Ishiyama, K

    2011-01-01

    This paper presents a centrifugal force based magnetic micro-pump for the pumping of blood. Most blood pumps are driven by an electrical motor with wired control. To develop a wireless and battery-free blood pump, the proposed pump is controlled by external rotating magnetic fields with a synchronized impeller. Synchronization occurs because the rotor is divided into multi-stage impeller parts and NdFeB permanent magnet. Finally, liquid is discharged by the centrifugal force of multi-stage impeller. The proposed pump length is 30 mm long and 19 mm in diameter which much smaller than currently pumps; however, its pumping ability satisfies the requirement for a blood pump. The maximum pressure is 120 mmHg and the maximum flow rate is 5000ml/min at 100 Hz. The advantage of the proposed pump is that the general mechanical problems of a normal blood pump are eliminated by the proposed driving mechanism.

  10. Centrifugal Force Based Magnetic Micro-Pump Driven by Rotating Magnetic Fields

    Kim, S. H.; Hashi, S.; Ishiyama, K.

    2011-01-01

    This paper presents a centrifugal force based magnetic micro-pump for the pumping of blood. Most blood pumps are driven by an electrical motor with wired control. To develop a wireless and battery-free blood pump, the proposed pump is controlled by external rotating magnetic fields with a synchronized impeller. Synchronization occurs because the rotor is divided into multi-stage impeller parts and NdFeB permanent magnet. Finally, liquid is discharged by the centrifugal force of multi-stage impeller. The proposed pump length is 30 mm long and19 mm in diameter which much smaller than currently pumps; however, its pumping ability satisfies the requirement for a blood pump. The maximum pressure is 120 mmHg and the maximum flow rate is 5000ml/min at 100 Hz. The advantage of the proposed pump is that the general mechanical problems of a normal blood pump are eliminated by the proposed driving mechanism.

  11. THE MUSLIM BROTHERHOOD: A CENTRIFUGAL OR CENTRIPETAL FORCE?

    Athina Lampridi-Kemou

    2011-04-01

    Full Text Available Before the third Egyptian revolution in early 2011, the Muslim Brotherhood was considered the only real opposition capable of challenging the hegemonic government of the Egyptian regime, owing to the popular support the organisation enjoyed; much greater than that of the opposition parties. However, change has not come through the Brotherhood, but through the Egyptian people themselves. In all these years that the Brotherhood has existed on the Egyptian political stage, neither its significant logistic and economic resources nor its dominant role in opposition politics have contributed to any change in the country’s power structure. The aim of this article is to show that the policies adopted by the Muslim Brotherhood in their interaction with the Hosni Mubarak government – both when they were in confrontation and in phases of accommodation – have only helped to maintain the status quo, and that they have, therefore, constituted a centripetal force with respect to the regime. This analysis may also offer a few clues as to the organisation’s future behaviour.

  12. Centripetal and centrifugal forces in the moral circle: Competing constraints on moral learning.

    Graham, Jesse; Waytz, Adam; Meindl, Peter; Iyer, Ravi; Young, Liane

    2017-10-01

    The idea of the moral circle pictures the self in the center, surrounded by concentric circles encompassing increasingly distant possible targets of moral concern, including family, local community, nation, all humans, all mammals, all living things including plants, and all things including inanimate objects. The authors develop the idea of two opposing forces in people's moral circles, with centripetal forces pulling inward, urging greater concern for close others than for distant others, and centrifugal forces pushing outward, resisting "drawing the line" anywhere as a form of prejudice and urging egalitarian concern for all regardless of social distance. Review of the developmental literature shows very early emergence of both moral forces, suggesting at least partly intuitive bases for each. Moral education approaches favoring one force over the other are compared, to show how these forces can provide constraints on moral learning. Finally, the centripetal/centrifugal forces view is applied to current moral debates about empathy and about politics. The authors argue that this view helps us see how intercultural and interpersonal disagreements about morality are based in intrapersonal conflicts shared by all people. Copyright © 2016. Published by Elsevier B.V.

  13. Confinement of plasma along shaped open magnetic fields from the centrifugal force of supersonic plasma rotation.

    Teodorescu, C; Young, W C; Swan, G W S; Ellis, R F; Hassam, A B; Romero-Talamas, C A

    2010-08-20

    Interferometric density measurements in plasmas rotating in shaped, open magnetic fields demonstrate strong confinement of plasma parallel to the magnetic field, with density drops of more than a factor of 10. Taken together with spectroscopic measurements of supersonic E × B rotation of sonic Mach 2, these measurements are in agreement with ideal MHD theory which predicts large parallel pressure drops balanced by centrifugal forces in supersonically rotating plasmas.

  14. Study of vapour phase dynamics with nitrogen boiling in the field of centrifugal forces

    Levchenko, N.M.; Kolod'ko, I.M.

    1987-01-01

    The vapour phase dynamics during film boiling of liquid nitrogen on horizontal wire in the field of centrifugal forces has been studied experimentally in a wide range of overloads(1 ≤ η ≤ 375) and heat fluxes (q kp2 ≤ q ≤ 4q kpi ). The available data confirmed and the theoretical relationships suggested make it possible to calculate the hydrodynamic film boiling parameters (wave length, bubble departure diameter and frequency) for other liquids

  15. Estimation of the radial force using a disturbance force observer for a magnetically levitated centrifugal blood pump.

    Pai, C N; Shinshi, T; Shimokohbe, A

    2010-01-01

    Evaluation of the hydraulic forces in a magnetically levitated (maglev) centrifugal blood pump is important from the point of view of the magnetic bearing design. Direct measurement is difficult due to the absence of a rotor shaft, and computational fluid dynamic analysis demands considerable computational resource and time. To solve this problem, disturbance force observers were developed, using the radial controlled magnetic bearing of a centrifugal blood pump, to estimate the radial forces on the maglev impeller. In order to design the disturbance observer, the radial dynamic characteristics of a maglev impeller were evaluated under different working conditions. It was observed that the working fluid affects the additional mass and damping, while the rotational speed affects the damping and stiffness of the maglev system. Based on these results, disturbance force observers were designed and implemented. The designed disturbance force observers present a bandwidth of 45 Hz. In non-pulsatile conditions, the magnitude of the estimated radial thrust increases in proportion to the flowrate, and the rotational speed has little effect on the force direction. At 5 l/min against 100 mmHg, the estimated radial thrust is 0.95 N. In pulsatile conditions, this method was capable of estimating the pulsatile radial thrust with good response.

  16. Plasma centrifuge

    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)

  17. Static deformation of a heavy spring due to gravity and centrifugal force

    Essen, Hanno; Nordmark, Arne, E-mail: hanno@mech.kth.s [Department of Mechanics, KTH, SE-100 44 Stockholm (Sweden)

    2010-05-15

    The static equilibrium deformation of a heavy spring due to its own weight is calculated for two cases: first for a spring hanging in a constant gravitational field, and then for a spring which is at rest in a rotating system where it is stretched by the centrifugal force. Two different models are considered: first a discrete model assuming a finite number of point masses connected by springs of negligible weight, and then the continuum limit of this model. In the second case, the differential equation for the deformation is obtained by demanding that the potential energy is minimized. In this way a simple application of the variational calculus is obtained.

  18. Study of vapour phase dynamics with nitrogen boiling in the field of centrifugal forces

    Levchenko, N M; Kolod' ko, I M

    1987-07-01

    The vapour phase dynamics during film boiling of liquid nitrogen on horizontal wire in the field of centrifugal forces has been studied experimentally in a wide range of overloads(1 less than or equal to eta less than or equal to 375) and heat fluxes (q/sub kp2/ less than or equal to q less than or equal to 4q/sub kpi/). The available data confirmed and the theoretical relationships suggested make it possible to calculate the hydrodynamic film boiling parameters (wave length, bubble departure diameter and frequency) for other liquids.

  19. Alternative polymer separation technology by centrifugal force in a melted state

    Dobrovszky, Károly; Ronkay, Ferenc

    2014-01-01

    Highlights: • Waste separation should take place at high purity. • Developed a novel, alternative separation method, where the separation occurred in a melted state by centrifugal forces. • Possibility of separation two different plastics into neat fractions. • High purity fractions were established at granulates and also at prefabricated blend. • Results were verified by DSC, optical microscopy and Raman spectroscopy. - Abstract: In order to upgrade polymer waste during recycling, separation should take place at high purity. The present research was aimed to develop a novel, alternative separation opportunity, where the polymer fractions were separated by centrifugal force in melted state. The efficiency of the constructed separation equipment was verified by two immiscible plastics (polyethylene terephthalate, PET; low density polyethylene, LDPE), which have a high difference of density, and of which large quantities can also be found in the municipal solid waste. The results show that the developed equipment is suitable not only for separating dry blended mixtures of PET/LDPE into pure components again, but also for separating prefabricated polymer blends. By this process it becomes possible to recover pure polymer substances from multi-component products during the recycling process. The adequacy of results was verified by differential scanning calorimetry (DSC) measurement as well as optical microscopy and Raman spectroscopy

  20. Plasma membrane NADH oxidase of maize roots responds to gravity and imposed centrifugal forces

    Bacon, E.; Morre, D. J.

    2001-01-01

    NADH oxidase activities measured with excised roots of dark-grown maize (Zea mays) seedlings and with isolated plasma membrane vesicles from roots of dark-grown maize oscillated with a regular period length of 24 min and were inhibited by the synthetic auxin 2,4-dichlorophenoxyacetic [correction of dichorophenoxyacetic] acid. The activities also responded to orientation with respect to gravity and to imposed centrifugal forces. Turning the roots upside down resulted in stimulation of the activity with a lag of about 10 min. Returning the sections to the normal upright position resulted in a return to initial rates. The activity was stimulated reversibly to a maximum of about 2-fold with isolated plasma membrane vesicles, when subjected to centrifugal forces of 25 to 250 x g for 1 to 4 min duration. These findings are the first report of a gravity-responsive enzymatic activity of plant roots inhibited by auxin and potentially related to the gravity-induced growth response. c2001 Editions scientifiques et medicales Elsevier SAS.

  1. Alternative polymer separation technology by centrifugal force in a melted state

    Dobrovszky, Károly; Ronkay, Ferenc, E-mail: ronkay@pt.bme.hu

    2014-11-15

    Highlights: • Waste separation should take place at high purity. • Developed a novel, alternative separation method, where the separation occurred in a melted state by centrifugal forces. • Possibility of separation two different plastics into neat fractions. • High purity fractions were established at granulates and also at prefabricated blend. • Results were verified by DSC, optical microscopy and Raman spectroscopy. - Abstract: In order to upgrade polymer waste during recycling, separation should take place at high purity. The present research was aimed to develop a novel, alternative separation opportunity, where the polymer fractions were separated by centrifugal force in melted state. The efficiency of the constructed separation equipment was verified by two immiscible plastics (polyethylene terephthalate, PET; low density polyethylene, LDPE), which have a high difference of density, and of which large quantities can also be found in the municipal solid waste. The results show that the developed equipment is suitable not only for separating dry blended mixtures of PET/LDPE into pure components again, but also for separating prefabricated polymer blends. By this process it becomes possible to recover pure polymer substances from multi-component products during the recycling process. The adequacy of results was verified by differential scanning calorimetry (DSC) measurement as well as optical microscopy and Raman spectroscopy.

  2. The centrifugal and centripetal force influence on spatial competition of agricultural land in Bandung Metropolitan Region

    Sadewo, E.

    2017-06-01

    Agricultural activity has suffered a massive land functional shift caused by market mechanism in Bandung metropolitan region (BMR). We argue that the existence of agricultural land in urban spatial structure is the result of interaction between centrifugal and centripetal force on spatial competition. This research aims to explore how several recognized centrifugal and centripetal force influence to the existence of agricultural land in BMR land development. The analysis using multivariate regression indicates that there exists spatial competition between population density and degree of urbanization with agricultural land areas. Its extended spatial regression model suggested that neighboring situation plays an important role to preserve agricultural land areas existences in BMR. Meanwhile, the influence of distance between the location of the city center and employment opportunities is found to be insignificant in the spatial competition. It is opposed to the theory of von Thünen and monocentric model in general. One of the possible explanation of such condition is that the assumption of centrality does not met. In addition, the agricultural land density decay in the southern parts of the area was related to its geographical conditions as protected areas or unfavorable for farming activity. It is suggested that BMR was in the early phase of polycentric development. Hence, better policies that lead redirected development to the southern part of the region is needed as well as population control and regulation of land use.

  3. Effect of centrifugal force on natural frequency of lateral vibration of rotating shafts

    Behzad, M.; Bastami, A. R.

    2004-07-01

    This paper investigates the effect of shaft rotation on its natural frequency. Apart from gyroscopic effect, the axial force originated from centrifugal force and the Poisson effect results in change of shaft natural frequency. D'Alembert principle for shaft in cylindrical co-ordinate system, along with the stress-strain relation, gives the non-homogenous linear differential equation, which can be used to calculate axial stress in the shaft. Numerical results of this study show that axial stress produced by shaft rotation has a major effect on the natural frequency of long high-speed shafts, while shaft diameter has no influence on the results. In addition, change in lateral natural frequency due to gyroscopic effect is compared with the results of this study.

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

    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

  5. Commercial spaceflight participant G-force tolerance during centrifuge-simulated suborbital flight.

    Blue, Rebecca S; Riccitello, Jon M; Tizard, Julia; Hamilton, Richard J; Vanderploeg, James M

    2012-10-01

    Medical knowledge of the human body in microgravity and hypergravity is based upon studies of healthy individuals well-conditioned for such environments. Little data exist regarding the effects of spaceflight on untrained commercial passengers. We examined the responses of potential spaceflight participants (SFP) to centrifuge G-force exposure. There were 77 individuals (65 men, 12 women), 22-88 yr old, who underwent 6 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 two runs approximating a suborbital spaceflight profile. Data included blood pressure, electrocardiogram, and postrun questionnaires regarding motion sickness, disorientation, greyout, and other symptoms. Of the 77 participants, average age was 50.4 +/- 12.7 yr. Average heart rate (HR) varied by sex and direction of G-exposure (+Gz: F 150 +/- 19, M 123 +/- 27; +Gx: F 135 +/- 30, M 110 +/- 27). Age and peak HR were inversely related (HR 120: 47.1 +/- 10.9 yr). HR during peak G-exposure for the final run was associated with post-run imbalance (no imbalance: HR 126 +/- 26, imbalance: HR 145 +/- 21); no other significant hemodynamic change, sex, or age variation was associated with imbalance. Age and greyout were inversely associated; there was no association between greyout and vital sign change, sex, or G-force magnitude. Baseline/pretrial mean arterial pressure (MAP) was not associated with any symptoms. The results suggest that most individuals with well-controlled medical conditions can withstand acceleration forces involved in launch/landing profiles of commercial spaceflight vehicles. Further investigation will help refine which conditions present significant risk during suborbital flight and beyond.

  6. Simulation of Shuttle launch G forces and acoustic loads using the NASA Ames Research Center 20G centrifuge

    Shaw, T. L.; Corliss, J. M.; Gundo, D. P.; Mulenburg, G. M.; Breit, G. A.; Griffith, J. B.

    1994-01-01

    The high cost and long times required to develop research packages for space flight can often be offset by using ground test techniques. This paper describes a space shuttle launch and reentry simulating using the NASA Ames Research Center's 20G centrifuge facility. The combined G-forces and acoustic environment during shuttle launch and landing were simulated to evaluate the effect on a payload of laboratory rates. The launch G force and acoustic profiles are matched to actual shuttle launch data to produce the required G-forces and acoustic spectrum in the centrifuge test cab where the rats were caged on a free-swinging platform. For reentry, only G force is simulated as the aero-acoustic noise is insignificant compared to that during launch. The shuttle G-force profiles of launch and landing are achieved by programming the centrifuge drive computer to continuously adjust centrifuge rotational speed to obtain the correct launch and landing G forces. The shuttle launch acoustic environment is simulated using a high-power, low-frequency audio system. Accelerometer data from STS-56 and microphone data from STS-1 through STS-5 are used as baselines for the simulations. This paper provides a description of the test setup and the results of the simulation with recommendations for follow-on simulations.

  7. Impeller radial force evolution in a large double-suction centrifugal pump during startup at the shut-off condition

    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

  8. Impeller radial force evolution in a large double-suction centrifugal pump during startup at the shut-off condition

    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

  9. Effect of ultrasound and centrifugal force on carambola (Averrhoa carambola L.) slices during osmotic dehydration.

    Barman, Nirmali; Badwaik, Laxmikant S

    2017-01-01

    Osmotic dehydration (OD) of carambola slices were carried out using glucose, sucrose, fructose and glycerol as osmotic agents with 70°Bx solute concentration, 50°C of temperature and for time of 180min. Glycerol and sucrose were selected on the basis of their higher water loss, weight reduction and lowers solid gain. Further the optimization of OD of carambola slices (5mm thick) were carried out under different process conditions of temperature (40-60°C), concentration of sucrose and glycerol (50-70°Bx), time (180min) and fruit to solution ratio (1:10) against various responses viz. water loss, solid gain, texture, rehydration ratio and sensory score according to a composite design. The optimized value for temperature, concentration of sucrose and glycerol has been found to be 50°C, 66°Bx and 66°Bx respectively. Under optimized conditions the effect of ultrasound for 10, 20, 30min and centrifugal force (2800rpm) for 15, 30, 45 and 60min on OD of carambola slices were checked. The controlled samples showed 68.14% water loss and 13.05% solid gain in carambola slices. While, the sample having 30min ultrasonic treatment showed 73.76% water loss and 9.79% solid gain; and the sample treated with centrifugal force for 60min showed 75.65% water loss and 6.76% solid gain. The results showed that with increasing in treatment time the water loss, rehydration ratio were increased and solid gain, texture were decreased. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. A novel 3D-printed mechanical actuator using centrifugal force for magnetic resonance elastography.

    Neumann, Wiebke; Schad, Lothar R; Zollner, Frank G

    2017-07-01

    Magnetic resonance elastography (MRE) is a technique for the quantification of tissue stiffness during MR examinations. It requires consistent methods for mechanical shear wave induction to the region of interest in the human body to reliably quantify elastic properties of soft tissues. This work proposes a novel 3D-printed mechanical actuator using the principle of centrifugal force for wave induction. The driver consists of a 3D-printed turbine vibrator powered by compressed air (located inside the scanner room) and an active driver controlling the pressure of inflowing air (placed outside the scanner room). The generated force of the proposed actuator increases for higher actuation frequencies as opposed to conventionally used air cushions. There, the displacement amplitude decreases with increasing actuation frequency resulting in a smaller signal-to-noise ratio. An initial phantom study is presented which demonstrates the feasibility of the actuator for MRE. The wave-actuation frequency was regulated in a range between 15 Hz and 60 Hz for force measurements and proved sufficiently stable (± 0.3 Hz) for any given nominal frequency. The generated forces depend on the weight of the eccentric unbalance within the turbine and ranged between 0.67 N to 2.70 N (for 15 Hz) and 3.09 N to 7.77 N (for 60 Hz). Therefore, the generated force of the presented actuator increases with rotational speed of the turbine and offers an elegant solution for sufficiently large wave actuation at higher frequencies. In future work, we will investigate an optimal ratio of the weight of unbalance to the size of turbine for appropriately large but tolerable wave actuation for a given nominal frequency.

  11. Frictional characteristics of erythrocytes on coated glass plates subject to inclined centrifugal forces.

    Kandori, Takashi; Hayase, Toshiyuki; Inoue, Kousuke; Funamoto, Kenichi; Takeno, Takanori; Ohta, Makoto; Takeda, Motohiro; Shirai, Atsushi

    2008-10-01

    In recent years a diamond-like carbon (DLC) film and a 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer have attracted attention as coating materials for implantable artificial organs or devices. When these materials are coated on vascular devices, compatibility to blood is an important problem. The present paper focuses on friction characteristics of erythrocytes to these coating materials in a medium. With an inclined centrifuge microscope developed by the authors, observation was made for erythrocytes moving on flat glass plates with and without coating in a medium of plasma or saline under the effect of inclined centrifugal force. Friction characteristics of erythrocytes with respect to these coating materials were then measured and compared to each other to characterize DLC and MPC as coating materials. The friction characteristics of erythrocytes in plasma using the DLC-coated and noncoated glass plates are similar, changing approximately proportional to the 0.5th power of the cell velocity. The cells stick to these plates in saline as well, implying the influence of plasma protein. The results using the MPC-coated plate in plasma are similar to those of the other plates for large cell velocities, but deviate from the other results with decreased cell velocity. The results change nearly proportional to the 0.75th power of the cell velocity in the range of small velocities. The results for the MPC-coated plate in saline are similar to that in plasma but somewhat smaller, implying that the friction characteristics for the MPC-coated plate are essentially independent of plasma protein.

  12. EFFECT OF FORCED ROTATING VANELESS DIFFUSERS ON CENTRIFUGAL COMPRESSOR STAGE PERFORMANCE

    S. SERALATHAN

    2011-10-01

    Full Text Available Non-uniform flow at the exit of the centrifugal impeller mixes in the vaneless space of the diffuser causing a rise in static pressure as well as significant loss of total pressure. These mixing losses are usually an important source of inefficiency. Forced rotating vaneless diffusers is one such concept which reduces the energy losses associated with diffusion. Forced rotating vaneless diffuser involves the concept of blade cutback and shroud extension. In the present computational investigations, the effects of blade cutback of 5%, 10% and 20% of vane length, shroud extension of 10%, 20%, 30% and 40% of impeller tip diameter and impeller without shroud extension on flow diffusion and performance are analyzed, while all the other dimensions remaining same. The performance characteristics of various blade cutback configurations are less in terms of efficiency, energy coefficient as well as static pressure rise. The objective of obtaining higher static pressure rise with wide operating range and reduced losses over stationary vaned diffuser is achieved by shroud extension of 30%, followed by shroud extension of 20%.

  13. A Positive Cosmological Constant as Centrifugal Force in an Expanding Kantian Model of the Universe

    Sternglass, E. J.

    1998-05-01

    Recent redshift measurements of distant Type Ia supernovae appear to indicate that cosmic expansion has speeded up since these distant stars exploded, rather than slowing down under the action of gravity. These results suggest the existence of a repulsive force as originally assumed by Einstein through the introduction of the lambda constant. Such a repulsive force arises naturally as centrifugal force in the evolution of a hierarchically organized cosmological model involving a series of rotating structures of increasing size as originally suggested by Kant in the 18th century when combined with the idea of Lemaitre, according to which the universe and the observed systems arose in the course of repeated divisions by two of a primeval atom. As described in the AIP Conference Proceedings 254,105 (1992), if this atom is assumed to be a highly relativistic form of positronium or "quarkonium" at the Planck density one avoids an initial singularity and requires no other particles. The division process takes place in 27 stages of 10 divisions each beginning with a lower mass excited state of the original Lemaitre atom that forms a central cluster in which a quarter of the particles are initially retained. One then arrives at a model in which all structures are laid down in the form of massive "cold dark matter" during a period of exponential growth or inflation before the Big Bang, leading to an ultimately stable, closed "flat" universe of finite mass that explains the masses, sizes, rotational and expansion velocities and thus the Hubble constants of the various systems as well as the age of the universe since the Big Bang in good agreement with observations, using only e, mo, c and h.

  14. Multi-Stage Flotation for the Removal of Ash from Fine Graphite Using Mechanical and Centrifugal Forces

    Xiangning Bu; Tuantuan Zhang; Yaoli Peng; Guangyuan Xie; Erdong Wu

    2018-01-01

    Graphite ore collected from Hunan province, south China was characterized by chemical analysis, X-ray diffraction, and optical microscopy. Rougher and multi-stage flotation tests using a mechanical flotation cell and a flotation column containing an additional centrifugal force field were carried out to promote its grade and economic value. In rougher flotation, both the mechanical flotation cell and flotation column reduced the ash content of the graphite ore from 15.43% to 10.8%, while the ...

  15. Estimation of changes in dynamic hydraulic force in a magnetically suspended centrifugal blood pump with transient computational fluid dynamics analysis.

    Masuzawa, Toru; Ohta, Akiko; Tanaka, Nobuatu; Qian, Yi; Tsukiya, Tomonori

    2009-01-01

    The effect of the hydraulic force on magnetically levitated (maglev) pumps should be studied carefully to improve the suspension performance and the reliability of the pumps. A maglev centrifugal pump, developed at Ibaraki University, was modeled with 926 376 hexahedral elements for computational fluid dynamics (CFD) analyses. The pump has a fully open six-vane impeller with a diameter of 72.5 mm. A self-bearing motor suspends the impeller in the radial direction. The maximum pressure head and flow rate were 250 mmHg and 14 l/min, respectively. First, a steady-state analysis was performed using commercial code STAR-CD to confirm the model's suitability by comparing the results with the real pump performance. Second, transient analysis was performed to estimate the hydraulic force on the levitated impeller. The impeller was rotated in steps of 1 degrees using a sliding mesh. The force around the impeller was integrated at every step. The transient analysis revealed that the direction of the radial force changed dynamically as the vane's position changed relative to the outlet port during one circulation, and the magnitude of this force was about 1 N. The current maglev pump has sufficient performance to counteract this hydraulic force. Transient CFD analysis is not only useful for observing dynamic flow conditions in a centrifugal pump but is also effective for obtaining information about the levitation dynamics of a maglev pump.

  16. Detachment of solid particulate soils by centrifugal force part 3; Properties of direction for removal force. Enshinryoku ni yoru ryushi yogore no jokyo. dai sanpo; Jokyoryoku no hokosei

    Iwasaki, Y. (Koriyama Womens College, Fukushima (Japan)); Lee, S.H. (Tokyo Gakugei Univ., Tokyo (Japan)); Yabe, A. (Bunka Womens Univ., Tokyo (Japan))

    1991-01-20

    Removal by centrigugal force of polystyrene-latex particles with particle sizes of 5, 10 and 15 {mu} m adhering to a glass substrate is studied. Washing was carried out by using an ultracentrifuge provided with an angular rotor, with a rotor angle {theta} of 0 {approximately} 60 {degree}, varying the ratio of horizontal component Fh to vertical component Fv from 1:0 to 1:1.73. Washing was further carried out, changing an angle {theta}{prime} of centrifugal force to the surface on which the particles adhered. From this experiment, the following conclusions were obtained. The less the contribution of Fv to the constant Fh, or reversely the greater the contribution of Fh to the constant Fv, the more was the extent of removal. When the surface on which the particles adhered was turned to the direction pressed by centrifugal force, Fv acted negatively for removal of particles and exhibited a different tendency from that when turned to the the centrifugal direction. When {theta}{prime} was 180 {degree}, the removal force giving an extent of removal of about 80% was 1.5 {times} 10 {sup {minus} 9} N for 5 and 10 {mu} m particles, and 25 {times} 10 {sup {minus} 9} N for 15 {mu} m particles. 11 refs., 14 figs., 3 tabs.

  17. The effect of centrifugation at various g force levels on rheological properties of rat, dog, pig and human red blood cells.

    Kiss, Ferenc; Toth, Eniko; Miszti-Blasius, Kornel; Nemeth, Norbert

    2016-01-01

    Laboratory investigations often require centrifugation of blood samples for various erythrocyte tests. Although there is a lack of data about the effect of centrifugation at various g force levels on erythrocyte rheological properties. We aimed to investigate the effect of a 10-minute centrifugation at 500, 1000 or 1500 g at 15°C of rat, dog, pig and human venous (K3-EDTA, 1.5 mg/ml) blood samples. Hematological parameters, erythrocyte deformability, cell membrane stability, osmotic gradient ektacytometry (osmoscan) and erythrocyte aggregation were determined. Hematological and erythrocyte deformability parameters showed interspecies differences, centrifugation caused no significant alterations. Cell membrane stability for human erythrocytes centrifuged at higher g level showed less decrease in deformability. Osmoscan O min parameter showed slight elevation in dog centrifuged aliquots. Erythrocyte aggregation parameters changed unexpectedly. Rat and dog erythrocyte aggregation indices significantly dropped in centrifuged aliquots. Pig erythrocyte aggregation indices increased significantly after centrifugation. Human erythrocyte aggregation was the most stable one among the investigated species. The used centrifugation protocols caused the largest alterations in erythrocyte aggregation in a controversial way among the investigated species. On the other hand, erythrocyte deformability parameters were stable, cell membrane stability and osmoscan data show minor shifts.

  18. SEAL FOR HIGH SPEED CENTRIFUGE

    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.

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

    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.

  20. PARAMETER DETERMINATION FOR ADDITIONAL OPERATING FORCE MECHANISM IN DEVICE FOR PNEUMO-CENTRIFUGAL MACHINING OF BALL-SHAPED WORKPIECES

    A. A. Sukhotsky

    2014-01-01

    Full Text Available The paper describes development of the methodology for optimization of parameters for an additional operating force mechanism in a device for pneumo-centrifugal machining of glass balls. Specific feature in manufacturing glass balls for micro-optics in accordance with technological process for obtaining ball-shaped workpieces is grinding and polishing of spherical surface in a free state. In this case component billets of future balls are made in the form of cubes and the billets are given preliminary a form of ball with the help of rough grinding. An advanced method for obtaining ball-shaped work-pieces from brittle materials is a pneumocentrifugal machining. This method presupposes an application of two conic rings with abrasive working surfaces which are set coaxially with large diameters to each other and the billets are rolled along these rings. Rotation of the billets is conveyed by means of pressure medium.The present devices for pneumo-centrifugal machining are suitable for obtaining balls up to 6 mm. Machining of the work-pieces with full spherical surfaces and large diameter is non-productive due to impossibility to ensure a sufficient force on the billet in the working zone. For this reason the paper proposes a modified device where an additional force on the machined billet is created by upper working disc that is making a reciprocating motion along an axis of abrasive conic rings. The motion is realized with the help of a cylindrical camshaft mechanism in the form of a ring with a profile working end face and the purpose of present paper is to optimize parameters of the proposed device.The paper presents expressions for calculation of constitutive parameters of the additional operating force mechanism including parameters of loading element motion, main dimensions of the additional operating force mechanism and parameters of a profile element in the additional operating force mechanism.Investigation method is a mathematical

  1. Microfluidic devices, systems, and methods for quantifying particles using centrifugal force

    Schaff, Ulrich Y.; Sommer, Gregory J.; Singh, Anup K.

    2015-11-17

    Embodiments of the present invention are directed toward microfluidic systems, apparatus, and methods for measuring a quantity of cells in a fluid. Examples include a differential white blood cell measurement using a centrifugal microfluidic system. A method may include introducing a fluid sample containing a quantity of cells into a microfluidic channel defined in part by a substrate. The quantity of cells may be transported toward a detection region defined in part by the substrate, wherein the detection region contains a density media, and wherein the density media has a density lower than a density of the cells and higher than a density of the fluid sample. The substrate may be spun such that at least a portion of the quantity of cells are transported through the density media. Signals may be detected from label moieties affixed to the cells.

  2. CENTRIFUGE APPARATUS

    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.

  3. Multi-Stage Flotation for the Removal of Ash from Fine Graphite Using Mechanical and Centrifugal Forces

    Xiangning Bu

    2018-01-01

    Full Text Available Graphite ore collected from Hunan province, south China was characterized by chemical analysis, X-ray diffraction, and optical microscopy. Rougher and multi-stage flotation tests using a mechanical flotation cell and a flotation column containing an additional centrifugal force field were carried out to promote its grade and economic value. In rougher flotation, both the mechanical flotation cell and flotation column reduced the ash content of the graphite ore from 15.43% to 10.8%, while the yield of the flotation column (91.41% was much higher than that of the mechanical flotation cell (50%. In the presence of hydrophobic graphite, the seriously entrained gangue restricted further improvement in the quality and economic value of the graphite ore. Therefore, multi-stage flotation circuits were employed to diminish this entrainment. Multi-stage flotation circuits using the two flotation devices further decreased the ash content of the graphite ore to ~8%, while the yield when using the flotation column was much higher than that obtained from the mechanical flotation cell employed. On the other hand, the ash removal efficiency of the flotation column was 3.82-fold higher than that observed for the mechanical flotation cell. The Cleaner 3 flotation circuit using the flotation column decreased the ash content in graphite from 15.43% to 7.97% with a yield of 77.53%.

  4. 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.

    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.

  5. Numerical research on the effects of impeller pump-out vanes on axial force in a solid-liquid screw centrifugal pump

    Cheng, X R; Li, R N; Gao, Y; Guo, W L

    2013-01-01

    A commercial CFD code has been used to predict the performance of a screw centrifugal pump with pump-out vanes, especially when changing regularity of impeller axial force based on the solid-liquid two-phase flow. The Unsteady Reynolds Averaged Navier-Stokes (URANS) approach has been applied to solve the unsteady, incompressible, three-dimensional turbulent. The SIMPLEC algorithm, standard wall functions and mix two-phase flow model were applied. The RNG k ε-model was used to account the turbulence effects. By changing the number of impeller pump-out vanes and width, six different screw centrifugal pump numerical simulation projects were given, and each scheme in the different solid volume fraction were calculated respectively. The change rules of axial force, velocity and pressure distribution of flow field were obtained on the different condition and different volume fraction. The results showed that the axial forces values based solid-fluid two-phase greater than based single-phase clear water, but both changing regularity of the axial force were consistent; as same condition, the same solid-phase volume concentration, with the increase of pump-out vanes number or width, the impeller axial force increased as well. Meanwhile the number of the pump-out vanes and the width of pump-out vanes in balancing the impeller axial force, there are the most optimal value

  6. Centrifugal pumps

    Gülich, Johann Friedrich

    2014-01-01

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

  7. Centrifugal pump handbook

    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

  8. CENTRIFUGAL SEPARATORS

    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

    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. Detection of intranuclear forces by the use of laser optics during the recovery process of elongated interphase nuclei in centrifuged protonemal cells of Adiantum capillus-veneris

    Wunsch, C.; Kurachi, M.; Kikumoto, M.; Tashiro, H.; Wada, M.

    1998-01-01

    For the direct investigation of intranuclear dynamics in living cells, extremely deformed nuclei of basipetally centrifuged protonemal cells of the fern Adiantum capillusveneris were manipulated by the laser rap and the laser scalpel. Whereas the nucleolus was tightly fixed at the central position inside the non-centrifuged nucleus and proved to be immovable by the optical trap, it could easily be trapped and moved towards three directions inside the bubble-like terminal widening of the basal thread-like extension of centrifuged nuclei. Due to the connection of the nucleolus to the chromatin inside the nuclear thread (NT), moving was not possible against the direction of the nuclear apical main body. Nucleoli in recovered nuclei were again immovable, thus indicating the presence of a dynamic nucleolar anchoring system inside the nucleus. When the nucleolus in the bubble was arrested during the thread shortening process by the optical trap, the acropetal movement of the bubble continued. Probably dye to dragging forces, some nucleoli became stretched, and a thick strand of a still unknown composition stretched between the nucleolus and the insertion site of the shortening NT. To assess whether the shrinking of the nuclear envelop (NE) and the shortening of the chromatin inside the NT were independent processes, the chromatin above the bubble was cut inside the Nt by the laser scalpel. After severance, a gap between the nucleolus and the end of the chromatin strand in the NT indicated the shortening of the chromatin inside the Nt. From these findings it was concluded that a shortening force was existing in the chromatin of the NT and that probably no physical link existed between the chromatin and the NE

  11. Influence of the centrifugal force and parallel dynamics on the toroidal momentum transport due to small scale turbulence in a tokamak

    Peeters, A. G.; Camenen, Y.; Casson, F. J.; Hornsby, W. A.; Snodin, A. P.; Strintzi, D.; Angioni, C.

    2009-01-01

    The paper derives the gyro-kinetic equation in the comoving frame of a toroidally rotating plasma, including both the Coriolis drift effect [A. G. Peeters et al., Phys. Rev. Lett. 98, 265003 (2007)] as well as the centrifugal force. The relation with the laboratory frame is discussed. A low field side gyro-fluid model is derived from the gyro-kinetic equation and applied to the description of parallel momentum transport. The model includes the effects of the Coriolis and centrifugal force as well as the parallel dynamics. The latter physics effect allows for a consistent description of both the Coriolis drift effect as well as the ExB shear effect [R. R. Dominguez and G. M. Staebler, Phys. Fluids B 5, 3876 (1993)] on the momentum transport. Strong plasma rotation as well as parallel dynamics reduce the Coriolis (inward) pinch of momentum and can lead to a sign reversal generating an outward pinch velocity. Also, the ExB shear effect is, in a similar manner, reduced by the parallel dynamics and stronger rotation.

  12. Plasma centrifuges

    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

  13. Centrifuge apparatus

    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.

  14. Quantification of platelets and platelet derived growth factors from platelet-rich-plasma (PRP) prepared at different centrifugal force (g) and time.

    Arora, Satyam; Doda, Veena; Kotwal, Urvershi; Dogra, Mitu

    2016-02-01

    Platelet derived biomaterials represent a key source of cytokines and growth factors extensively used for tissue regeneration; wound healing and tissue repair. Our study was to quantify platelets and growth factors released by PRP when prepared at different centrifugal force (g) and time. Our study was approved by the institutional ethical committee. One hundred millilitres of whole blood (WB) was collected in bag with CPDA as the anticoagulant(AC); (14 mL for 100 mL WB ratio). Nine aliquots of 10 mL each were made from the bag and set of three aliquots were made a group. PRP was prepared at varying centrifugal force (group A: -110 g, group B: -208 g & group C: -440 g) & time (1: -5 min, 2: -10 min & 3: -20 min). Contents of each PRP prepared were analysed. Commercial sandwich ELISA kits were used to quantify the concentrations of CD62P (Diaclone SAS; France), Platelet derived growth factors-AB (Qayee-Bio; China), transforming growth factor-β1 (DRG; Germany) and vascular endothelial growth factor (Boster Immuno Leader; USA) released in each PRP prepared. Eight volunteers were enrolled in the study (24-30 years). The baseline blood counts of all the volunteers were comparable (p ≥ 0.05). Mean ± SD of platelet yield of all nine groups ranged from 17.2 ± 4.2% to 78.7 ± 5.7%. Each PRP was activated with calcified thromboplastin to quantify the growth factors released by them. Significantly higher (p < 0.05) transforming growth factor-β1 and vascular endothelial growth factor were released compared to the baseline. Our study highlights the variation in both force (g) and time results in changes at cellular level and growth factor concentrations. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    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. Waves in Strong Centrifugal Field

    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. The Influence of Swirl Brakes and a Tip Discharge Orifice on the Rotordynamic Forces Generated by Discharge-to-Suction Leakage Flows in Shrouded Centrifugal Pumps

    Sivo, Joseph M.; Acosta, A. J.; Brennen, C. E.; Caughey, T. K.

    1993-01-01

    Recent experiments conducted in the Rotor Force Test Facility at the California Institute of Technology have examined the effects of a tip leakage restriction and swirl brakes on the rotordynamic forces due to leakage flows on an impeller undergoing a prescribed circular whirl. The experiments simulate the leakage flow conditions and geometry of the Alternate Turbopump Design (ATD) of the Space Shuttle High Pressure Oxygen Turbopump and are critical to evaluating the pump's rotordynamic instability problems. Previous experimental and analytical results have shown that discharge-to-suction leakage flows in the annulus of a shrouded centrifugal pump contribute substantially to the fluid induced rotordynamic forces. Also, previous experiments have shown that leakage inlet (pump discharge) swirl can increase the cross-coupled stiffness coefficient and hence increase the range of positive whirl for which the tangential force is destabilizing. In recent experimental work, the present authors demonstrated that when the swirl velocity within the leakage path is reduced by the introduction of ribs or swirl brakes, then a substantial decrease in both the destabilizing normal and tangential forces could be achieved. Motivation for the present research is that previous experiments have shown that restrictions such as wear rings or orifices at pump inlets affect the leakage forces. Recent pump designs such as the Space Shuttle Alternate Turbopump Design (ATD) utilize tip orifices at discharge for the purpose of establishing axial thrust balance. The ATD has experienced rotordynamic instability problems and one may surmise that these tip discharge orifices may also have an important effect on the normal and tangential forces in the plane of impeller rotation. The present study determines if such tip leakage restrictions contribute to undesirable rotordynamic forces. Additional motivation for the present study is that the widening of the leakage path annular clearance and the

  18. Effect of Perturbations in Coriolis and Centrifugal Forces on the Nonlinear Stability of Equilibrium Point in Robe's Restricted Circular Three-Body Problem

    P. P. Hallan

    2008-01-01

    Full Text Available The effect of perturbations in Coriolis and cetrifugal forces on the nonlinear stability of the equilibrium point of the Robe's (1977 restricted circular three-body problem has been studied when the density parameter K is zero. By applying Kolmogorov-Arnold-Moser (KAM theory, it has been found that the equilibrium point is stable for all mass ratios μ in the range of linear stability 8/9+(2/3((43/25ϵ1−(10/3ϵ<μ<1, where ϵ and ϵ1 are, respectively, the perturbations in Coriolis and centrifugal forces, except for five mass ratios μ1=0.93711086−1.12983217ϵ+1.50202694ϵ1, μ2 = 0.9672922−0.5542091ϵ+ 1.2443968ϵ1, μ3=0.9459503−0.70458206ϵ+ 1.28436549ϵ1, μ4=0.9660792−0.30152273ϵ + 1.11684064ϵ1, μ5=0.893981−2.37971679ϵ + 1.22385421ϵ1, where the theory is not applicable.

  19. Fundamental investigation on interaction forces in bubble swarms and its application to the design of centrifugal separators

    Wisman, R.

    1979-01-01

    The present investigation deals with two aspects of gas-liquid flows, viz. interaction forces between the phases in bubble swarms and numerical description of rotating gas-liquid flows. The insight obtained was applied to the development of axial gas-liquid cyclones, as used i.a. as primary separators in nuclear boiling water reactors. (Auth.)

  20. Motion of a Point Mass in a Rotating Disc: A Quantitative Analysis of the Coriolis and Centrifugal Force

    Haddout, Soufiane

    2016-06-01

    In Newtonian mechanics, the non-inertial reference frames is a generalization of Newton's laws to any reference frames. While this approach simplifies some problems, there is often little physical insight into the motion, in particular into the effects of the Coriolis force. The fictitious Coriolis force can be used by anyone in that frame of reference to explain why objects follow curved paths. In this paper, a mathematical solution based on differential equations in non-inertial reference is used to study different types of motion in rotating system. In addition, the experimental data measured on a turntable device, using a video camera in a mechanics laboratory was conducted to compare with mathematical solution in case of parabolically curved, solving non-linear least-squares problems, based on Levenberg-Marquardt's and Gauss-Newton algorithms.

  1. 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

    Fraters, D.; Boom, G.J.F.L.; Boumans, L.J.M.; Weerd, H. de; Wolters, M.

    2017-01-01

    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

  2. Mathematical and physical modeling of rainfall in centrifuge

    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...

  3. Gas dynamics in strong centrifugal fields

    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. Theoretical investigations on plasma centrifuges

    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

  5. Radial loads and axial thrusts on centrifugal pumps

    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

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

    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.

  7. Separations by centrifugal phenomena

    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

  8. Vacuum chamber-free centrifuge with magnetic bearings.

    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.

  9. Centrifugal precipitation chromatography

    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

  10. Relativistic centrifugal instability

    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.

  11. Centrifugal gas separator

    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.

  12. Enrichment: centrifuge process

    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. CENTRIFUGE END CAP

    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.

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

    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. Observations on centrifugation: application to centrifuge development.

    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.

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

    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.

  17. Gas dynamics in strong centrifugal fields

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

    2015-03-10

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

  18. Effect of centrifugal transverse wakefield for microbunch in bend

    Stupakov, G.V.

    1999-01-01

    We calculate centrifugal force for a short bunch in vacuum moving in a circular orbit and estimate the emittance growth of the beam in a bend due to this force. copyright 1999 American Institute of Physics

  19. Centrifuge modeling of monopiles

    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....

  20. Centrifugation speed affects light transmission aggregometry.

    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.

  1. Centrifuge design and development

    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)

  2. Centrifuge advances using HTS magnetic bearings

    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.

  3. Heat-Induced, Pressure-Induced and Centrifugal-Force-Induced Exact Axisymmetric Thermo-Mechanical Analyses in a Thick-Walled Spherical Vessel, an Infinite Cylindrical Vessel, and a Uniform Disk Made of an Isotropic and Homogeneous Material

    Vebil Yıldırım

    2017-07-01

    Full Text Available Heat-induced, pressure-induced, and centrifugal force-induced axisymmetric exact deformation and stresses in a thick-walled spherical vessel, a cylindrical vessel, and a uniform disk are all determined analytically at a specified constant surface temperature and at a constant angular velocity. The inner and outer pressures are both included in the formulation of annular structures made of an isotropic and homogeneous linear elastic material. Governing equations in the form of Euler-Cauchy differential equation with constant coefficients are solved and results are presented in compact forms. For disks, three different boundary conditions are taken into account to consider mechanical engineering applications. The present study is also peppered with numerical results in graphical forms.

  4. RESEARCH CENTRIFUGE- ADVANCED TOOL SEPERATION

    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...

  5. Research on the development of the centrifugal spinning

    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.

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

    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.

  7. Centrifuge enrichment program

    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

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

    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)

  9. Valve for gas centrifuges

    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.

  10. Centrifuge modelling of granular flows

    Cabrera, Miguel Angel; Wu, Wei

    2015-04-01

    A common characteristic of mass flows like debris flows, rock avalanches and mudflows is that gravity is their main driving force. Gravity defines the intensity and duration of the main interactions between particles and their surrounding media (particle-particle, particle-fluid, fluid-fluid). At the same time, gravity delimits the occurrence of phase separation, inverse segregation, and mass consolidation, among other phenomena. Therefore, in the understanding of the flow physics it is important to account for the scaling of gravity in scaled models. In this research, a centrifuge model is developed to model free surface granular flows down an incline at controlled gravity conditions. Gravity is controlled by the action of an induced inertial acceleration field resulting from the rotation of the model in a geotechnical centrifuge. The characteristics of the induced inertial acceleration field during flow are discussed and validated via experimental data. Flow heights, velocity fields, basal pressure and impact forces are measured for a range of channel inclinations and gravity conditions. Preliminary results enlighten the flow characteristics at variable gravity conditions and open a discussion on the simulation of large scale processes at a laboratory scale. Further analysis on the flow physics brings valuable information for the validation of granular flows rheology.

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

    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. A paper-polymer centrifugal device for low-cost sample pre-concentration and colorimetric lateral flow assay enhancement

    Wiederoder, MS

    2016-10-01

    Full Text Available This study describes a novel hybrid paper-polymer centrifugal microfluidic device for pre-concentration of E.coli and lateral flow immunoassay enhancement for water quality verification. The device balances rotational centrifugal force...

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

    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.

  14. Axial Force Analysis and Balance for Semi-open Centrifugal Pump Impeller%半开式离心泵轴向力分析及平衡

    陶晓

    2016-01-01

    When pump working, an axial force will be generated, affecting reliability and life time of pump.Using computational fluid dynamics method, the performance parameters of the pump at different speeds were obtained.The calculation results were very close to test results.It was proved that the simulation mode and computational method are relatively reliable.On the pump, balance holes with different diameter were cut to reduce axial force.The results show that the balance hole can effectively reduce axial force, at the same time it has little effect on the other properties of pump.At last, for the balance hole the optimum diameter is 2 mm.%泵在工作过程中存在着轴向力,影响泵的可靠性及使用寿命。利用计算流体力学方法,计算泵在不同转速下的性能参数,与试验结果相近,证明该计算模型、计算方法相对可信。进而对该模型开不同直径的平衡孔以泄压平衡轴向力。结果表明:平衡孔能够有效降低轴向力,同时对其他性能的影响较小。并选取直径2 mm平衡孔作为优选方案。

  15. Bifurcated equilibria in centrifugally confined plasma

    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.

  16. Pipeline system for gas centrifuge

    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.)

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

    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.

  18. Perceived radial translation during centrifugation

    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

  19. Human Powered Centrifuge

    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.

  20. Lightweight Shield for Centrifuge

    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.

  1. Multifunctional centrifugal grinding unit

    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

  2. Centrifugal blood pump 603

    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.

  3. Centrifugal analyzer development

    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

  4. New centrifugation blood culture device.

    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

  5. Flow control arrangements for centrifuges

    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)

  6. Separation parameters of gas centrifuges

    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

  7. Engineering design of centrifugal casting machine

    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.

  8. Centrifugal compressor case study

    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.

  9. Container for centrifuging blood

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

    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.

  11. Gas Centrifuges and Nuclear Proliferation

    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.

  12. Centrifugal potential energy : an astounding renewable energy concept

    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.

  13. Continuous centrifuge decelerator for polar molecules.

    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.

  14. The magnetic centrifugal mass filter

    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.

  15. The magnetic centrifugal mass filter

    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.

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

    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)

  17. Fluid dynamics and mass transfer in a gas centrifuge

    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)

  18. Convective instabilities in liquid centrifugation for nuclear wastes separation

    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.

  19. Centrifuge impact cratering experiment 5

    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.

  20. Centrifugal Casting Features/Metallurgical Characterization of Aluminum Alloys

    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)

  1. National geotechnical centrifuge

    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.

  2. Centrifugal-reciprocating compressor

    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.

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

    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.

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

    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

  5. Centrifugal shot blast system

    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

  6. Centrifuge treatment of coal tar

    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.

  7. NASA low speed centrifugal compressor

    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.

  8. EM Task 9 - Centrifugal Membrane Filtration

    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

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

    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

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

    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.

  11. Gas-centrifuge unit

    Stark, T.M.

    1977-01-01

    An isotope-enrichment unit is described for separating a gaseous mixture feedstock including a compound of a light nuclear isotope at a predetermined concentration and a compound of a heavy nuclear isotope at a predetermined concentration into at least two unit-output fractions including a waste fraction depleted in the light isotope to a predetermined concentration and a product fraction enriched in the light isotope to a predetermined concentration. The unit comprises a first group of cascades of gas centrifuges, each cascade having an enriching stage, a stripping stage, an input, a light-fraction output, and a heavy-fraction output for separating the gaseous-mixture feed stock into light and heavy gaseous-mixture fractions; and an auxillary cascade

  12. Gas centrifuge purge method

    Theurich, Gordon R.

    1976-01-01

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

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

    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.

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

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

  15. 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

    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)

  16. Microwave assisted centrifuge and related methods

    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.

  17. Uranium enrichment by gas centrifuge

    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

  18. Centar's gas centrifuge enrichment project

    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.)

  19. 75 FR 70300 - USEC, Inc.; American Centrifuge Lead Cascade Facility; American Centrifuge Plant; Notice of...

    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...

  20. Rotary drum for centrifuge

    Sakurai, Mitsuo; Ichinoto, Seiichi.

    1972-01-01

    An outwardly concaved metallic end plate is fitted into each end of a metallic rotary drum for a centrifuge until each end face of the drum is brought to bear upon a section of the end plate radially projected in a direction perpendicular to the axis of rotation of the drum, said section being provided at the marginal edge of the end plate. Following completion of the fitting operation, the end plate is welded to the rotary drum. During high speed rotation, the drum contracts axially and expands radially, while the concave end plate, radially tensioned due to the radial expansion of the drum, undergoes a reduction in its degree of concavity resulting in outwardly directed axial displacement of the end plate proper its marginal edge remaining unaffected relative to the drum. Such displacement conpensates for axial contraction of the drum. Since displacement of the end plate and contraction of the drum depend upon the speed of rotation, substantial axial distortion of the drum can be avoided relative to the end plates at both low and high speeds to permit a high degree of balance for the rotary drum. (Ohno, Y.)

  1. Centrifugal gas separator

    Sakurai, M

    1970-03-27

    A centrifugal gas separator of a highly endurable construction and with improved gas sealing qualities utilizes a cylincrical elastic bellows or similar system in cooperation with a system of dynamic pressure operable gas seals as means for removing separated gases from the interior of the rotor drum, collecting the separated gases in their respective separated gas chambers defined by the corresponding bellows and their supporting stationary wall members, gas seals and rotor end caps, and means for discharging to the exterior of the surrounding cylindrical wall member the gaseous components from their respective separated gas chambers. In the vicinity of the rotary drum motor is a mixed gas chamber and means for providing the gas mixture along a co-axial passage into the rotary drum chamber. Orifices are bored into the end caps of the rotary drum to direct the separated gases into the aforementioned separated gas chambers which, through the action of the gas seals, freely slide upon the rotating drum to collect and thereafter discharge the thus separated gases. Therefore, according to the present invention, helium gas used to prevent separated gas remixture is unnecessary and, furthermore, the gas seals and elastic bellows means provide an air-tight seal superior to that of the contact sealing system of the former art.

  2. Centrifugal gas separator

    Sakurai, Mitsuo.

    1970-01-01

    A centrifugal gas separator of a highly endurable construction and with improved gas sealing qualities utilizes a cylincrical elastic bellows or similar system in cooperation with a system of dynamic pressure operable gas seals as means for removing separated gases from the interior of the rotor drum, collecting the separated gases in their respective separated gas chambers defined by the corresponding bellows and their supporting stationary wall members, gas seals and rotor end caps, and means for discharging to the exterior of the surrounding cylindrical wall member the gaseous components from their respective separated gas chambers. In the vicinity of the rotary drum motor is a mixed gas chamber and means for providing the gas mixture along a co-axial passage into the rotary drum chamber. Orifices are bored into the end caps of the rotary drum to direct the separated gases into the aforementioned separated gas chambers which, through the action of the gas seals, freely slide upon the rotating drum to collect and thereafter discharge the thus separated gases. Therefore, according to the present invention, helium gas used to prevent separated gas remixture is unnecessary and, furthermore, the gas seals and elastic bellows means provide an air-tight seal superior to that of the contact sealing system of the former art. (K.J. Owens)

  3. Radwaste disposal drum centrifuge

    Rubin, L.S.; Deltete, C.P.; Crook, M.R.

    1988-01-01

    The drum or processing bowl of the DDC becomes the disposal container when the filling operation is completed. Rehandling of the processed resin is eliminated. By allowing the centrifugally compacted resin to remain in the processing container, extremely efficient waste packaging can be achieved. The dewatering results and volume reductions reported during 1986 were based upon laboratory scale testing sponsored by the Electric Power Research Institute (EPRI) and the Department of Energy (DOE). Since the publication of these preliminary results, additional testing using a full-scale prototype DDC has been completed, again under the auspices of the DOE. Full-scale testing has substantiated the results of earlier testing and has formed the basis for preliminary discussions with the U.S. Nuclear Regulatory Commission (NRC) regarding DDC licensing for radioactive applications. A comprehensive Topical Report and Process Control Program is currently being prepared for submittal to the NRC for review under a utility licensing action. Detailed cost-benefit analyses for actual plant operations have been prepared to substantiate the attractiveness of the DDC. Several methods to physically integrate a DDC into a nuclear power plant have also been developed

  4. Centrifugal Compressor Aeroelastic Analysis Code

    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.

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

    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

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

    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.

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

    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.

  8. EM Task 9 - Centrifugal membrane filtration

    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)

  9. The Advanced Gas Centrifuge program

    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

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

    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.

  11. Centrifugal trapping in the magnetotail

    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.

  12. Centrifugal trapping in the magnetotail

    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.

  13. Centrifugal acceleration of the polar wind

    Horwitz, J. L.; Ho, C. W.; Scarbro, H. D.; Wilson, G. R.; Moore, T. E.

    1994-01-01

    The effect of parallel ion acceleration associated with convection was first applied to energization of test particle polar ions by Cladis (1986). However, this effect is typically neglected in 'self-consistent' models of polar plasma outflow, apart from the fluid simulation by Swift (1990). Here we include approximations for this acceleration, which we broadly characterize as centrifugal in nature, in our time-dependent, semikinetic model of polar plasma outflow and describe the effects on the bulk parameter profiles and distribution functions of H+ and O+. For meridional convection across the pole the approximate parallel force along a polar magnetic field line may be written as F(sub cent, pole) = 1.5m(E(sub i))/B(sub i))squared (r(squared)/r(sup 3)(sub i)) where m is ion mass, r is geometric distance; and E(sub i), B(sub i) and r(sub i) refer to the electric and magnetic field magnitudes and geocentric distance at the ionosphere, respectively. For purely longitudinal convection along a constant L shell the parallel force is F(cent. long) = F(sub cent, pole)(1 - (r/(r(sub i)L))(sup 3/2)/(1 - 3r/(4 r(sub i)L))(sup 5/2). For high latitudes the difference between these two cases is relatively unimportant below approximately 5 R(sub E). We find that the steady state O+ bulk velocities and parallel temperatures strongly increase and decrease, respectively, with convection strength. In particular, the bulk velocities increase from near 0 km/s at 4000 km altitude to approximately 10 km/s at 5 R(sub E) geocentric distance for 50-mV/m ionospheric convection electric field. However, the centrifugal effect on the steady O+ density profiles depends on the exobase ion and electron temperatures: for low-base temperatures (T(sub i) = T(sub e) = 3000 K) the O+ density at high altitudes increases greatly with convection, while for higher base temperatures (T(sub i) = 5000 K, T(sub e) = 9000 K), the high-altitude O+ density decreases somewhat as convection is enhanced. The

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

    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.

  15. Smoothed Particle Hydro-dynamic Analysis of Improvement in Sludge Conveyance Efficiency of Screw Decanter Centrifuge

    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.

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

    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)

  17. Smoothed Particle Hydro-dynamic Analysis of Improvement in Sludge Conveyance Efficiency of Screw Decanter Centrifuge

    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.

  18. Theory and experiments on centrifuge cratering

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

    1980-01-01

    Centrifuge experimental techniques provide possibilities for laboratory simulation of ground motion and cratering effects due to explosive loadings. The results of a similarity analysis for the thermomechanical response of a continuun show that increased gravity is a necessary condition for subscale testing when identical materials for both model and prototype are being used. The general similarity requirements for this type of subscale testing are examined both theoretically and experimentally. The similarity analysis is used to derive the necessary and sufficient requirements due to the general balance and jump equations and gives relations among all the scale factors for size, density, stress, body forces, internal energy, heat supply, heat conduction, heat of detonation, and time. Additional constraints due to specific choices of material constitutive equations are evaluated separately. The class of consitutive equations that add no further requirements is identified. For this class of materials, direct simulation of large-scale cratering events at small scale on the centrifuge is possible and independent of the actual constitutive equations. For a rare-independent soil it is shown that a small experiment at gravity g and energy E is similar to a large event at 1 G but with energy equal to g 3 E. Consequently, experiments at 500 G with 8 grams of explosives can be used to

  19. Physical simulations using centrifuge techniques

    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

  20. New type of centrifugal extractor

    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

  1. Centrifugation and the Manhattan Project

    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.

  2. MEANS FOR DETERMINING CENTRIFUGE ALIGNMENT

    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.

  3. 76 FR 9613 - USEC Inc. (American Centrifuge Lead Cascade Facility and American Centrifuge Plant); Order...

    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...

  4. 77 FR 9273 - USEC Inc. (American Centrifuge Lead Cascade Facility and American Centrifuge Plant); Direct...

    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

  5. Life Sciences Centrifuge Facility assessment

    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.

  6. Laser and gas centrifuge enrichment

    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.

  7. Reflection of centrifugal pumps maintenance

    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)

  8. A variational principle for the plasma centrifuge

    Ludwig, G.O.

    1986-09-01

    A variational principle is derived which describes the stationary state of the plasma column in a plasma centrifuge. Starting with the fluid equations in a rotating frame the theory is developed using the method of irreversible thermodynamics. This formulation easily leads to an expression for the density distribution of the l-species at sedimentation equilibrium, taking into account the effect of the electric and magnetic forces. Assuming stationary boundary conditions and rigid rotation nonequilibrium states the condition for thermodynamic stability integrated over the volume of the system reduces, under certain restrictions, to the principle of minimum entropy production in the stationary state. This principle yields a variational problem which is equivalent to the original problem posed by the stationary fluid equations. The variational method is useful in achieving approximate solutions that give the electric potential and current distributions in the rotating plasma column consistent with an assumed plasma density profile. (Author) [pt

  9. Centrifugal separator cascade connected in zigzag manner

    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.)

  10. 21 CFR 864.5350 - Microsedimentation centrifuge.

    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...

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

    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.

  12. Multiphase flow modeling in centrifugal partition chromatography.

    Adelmann, S; Schwienheer, C; Schembecker, G

    2011-09-09

    The separation efficiency in Centrifugal Partition Chromatography (CPC) depends on selection of a suitable biphasic solvent system (distribution ratio, selectivity factor, sample solubility) and is influenced by hydrodynamics in the chambers. Especially the stationary phase retention, the interfacial area for mass transfer and the flow pattern (backmixing) are important parameters. Their relationship with physical properties, operating parameters and chamber geometry is not completely understood and predictions are hardly possible. Experimental flow visualization is expensive and two-dimensional only. Therefore we simulated the flow pattern using a volume-of-fluid (VOF) method, which was implemented in OpenFOAM®. For the three-dimensional simulation of a rotating FCPC®-chamber, gravitational centrifugal and Coriolis forces were added to the conservation equation. For experimental validation the flow pattern of different solvent systems was visualized with an optical measurement system. The amount of mobile phase in a chamber was calculated from gray scale values of videos recorded by an image processing routine in ImageJ®. To visualize the flow of the stationary phase polyethylene particles were used to perform a qualitative particle image velocimetry (PIV) analysis. We found a good agreement between flow patterns and velocity profiles of experiments and simulations. By using the model we found that increasing the chamber depth leads to higher specific interfacial area. Additionally a circular flow in the stationary phase was identified that lowers the interfacial area because it pushes the jet of mobile phase to the chamber wall. The Coriolis force alone gives the impulse for this behavior. As a result the model is easier to handle than experiments and allows 3D prediction of hydrodynamics in the chamber. Additionally it can be used for optimizing geometry and operating parameters for given physical properties of solvent systems. Copyright © 2011 Elsevier B

  13. Interrogation of fibre Bragg gratings through a fibre optic rotary joint on a geotechnical centrifuge

    Correia, Ricardo; James, Stephen W.; Marshall, Alec; Heron, Charles; Korposh, Sergiy

    2016-05-01

    The monitoring of an array of fibre Bragg gratings (FBGs) strain sensors was performed through a single channel, single mode fibre optic rotary joint (FORJ) mounted on a geotechnical centrifuge. The array of three FBGs was attached to an aluminum plate that was anchored at the ends and placed on the model platform of the centrifuge. Acceleration forces of up to 50g were applied and the reflection signal of the monitored FBGs recorded dynamically using a 2.5kHz FBG interrogator placed outside the centrifuge. The use of a FORJ allowed the monitoring of the FBGs without submitting the FBG interrogator to the high g-forces experienced in the centrifuge.

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

    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.

  15. An assessment of a spiral duct centrifuge using standard and high concentration aerosols

    Smith, A.D.

    1982-12-01

    The Stoeber spiral duct centrifuge has been calibrated by means of polystyrene latex microspheres for the subsequent measurement of aerosol particle size distributions. Intermediate (1 g m -3 ) ad high (100 g m -3 ) sodium chloride aerosol concentrations have been sampled by the centrifuge to determine possible limitations in the equipment. Corrections have to be made for the effect of Coriolis forces, and aerosol concentrations above 1 g m -3 should be diluted before sampling. The spiral duct centrifuge is an extremely versatile instrument for aerosol analysis, and shows a high degree of reliability when operated under well-defined conditions. (author)

  16. An experiment to test centrifugal confinement for fusion

    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

  17. On the efficiency of a fluid-fluid centrifugal separation

    Apazidis, N.

    1984-05-01

    Efficiency of a separation process of two immiscible incompressible fluids of different densities occuring under the influence of a combined centrifugal and gravitational force field is investigated. The analysis is based on the set of equations for a rotating two-phase flow of a mixture as presented by Greenspan (1983). The geometry of the separation process is considered and the total flow of the separated phases evaluated. (author)

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

    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

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

    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.

  20. Basic characteristics of centrifuges, (4)

    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.)

  1. Centrifugal pumps: fundamentals and classification

    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)

  2. Centrifuge pellet injector for JET

    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.)

  3. Centrifugal separation of mixture gases

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

    2008-01-01

    An attempt for single centrifugal separation of mixtures with different molecular formula was presented in this paper. The mixtures of SF 6 and CCl 3 F, and SF 6 and CCl 4 were chosen as the processing gases, which were prepared in three mass ratios, 0.5, 0.8 and 0.2, respectively. The separating characteristics such as the overall separation factors and the variation of cuts were studied. (author)

  4. Gas centrifuge bibliography 1970 - 1974

    Lowe, G.E.; Edwards, K.J.

    1978-05-01

    A bibliography, with abstract, is presented of the gas centrifuge literature published during 1970 to 1974. It supplements PG Information Series 25 (CA) which covered the period 1895 to 1970. Following reference to bibliographies, books and pamphlets, and a few items omitted from the previous bibliography, main items are grouped under the headings Reports, Journal articles and Conference papers and are listed chronologically. There are indexes to subject, author, and document number, the latter including the issuing body. (UK)

  5. Centrifugal pumps and allied machinery

    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.

  6. Tolerance of centrifuge-simulated suborbital spaceflight by medical condition.

    Blue, Rebecca S; Pattarini, James M; Reyes, David P; Mulcahy, Robert A; Garbino, Alejandro; Mathers, Charles H; Vardiman, Johnené L; Castleberry, Tarah L; Vanderploeg, James M

    2014-07-01

    We examined responses of volunteers with known medical disease to G forces in a centrifuge to evaluate how potential commercial spaceflight participants (SFPs) might tolerate the forces of spaceflight despite significant medical history. Volunteers were recruited based upon suitability for each of five disease categories (hypertension, cardiovascular disease, diabetes, lung disease, back or neck problems) or a control group. Subjects underwent seven centrifuge runs over 2 d. Day 1 consisted of two +G(z) runs (peak = +3.5 G(z), Run 2) and two +G(x), runs (peak = +6.0 G(x), Run 4). Day 2 consisted of three runs approximating suborbital spaceflight profiles (combined +G(x) and +G(z), peak = +6.0 G(x)/+4.0 G(z)). Data collected included blood pressure, electrocardiogram, pulse oximetry, neurovestibular exams, and post-run questionnaires regarding motion sickness, disorientation, grayout, and other symptoms. A total of 335 subjects registered for participation, of which 86 (63 men, 23 women, age 20-78 yr) participated in centrifuge trials. The most common causes for disqualification were weight and severe and uncontrolled medical or psychiatric disease. Five subjects voluntarily withdrew from the second day of testing: three for anxiety reasons, one for back strain, and one for time constraints. Maximum hemodynamic values recorded included HR of 192 bpm, systolic BP of 217 mmHg, and diastolic BP of 144 mmHg. Common subjective complaints included grayout (69%), nausea (20%), and chest discomfort (6%). Despite their medical history, no subject experienced significant adverse physiological responses to centrifuge profiles. These results suggest that most individuals with well-controlled medical conditions can withstand acceleration forces of launch and re-entry profiles of current commercial spaceflight vehicles.

  7. Centrifuge in Free Fall: Combustion at Partial Gravity

    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.

  8. Microvascular pressure responses of second-generation rats chronically exposed to 2 g centrifugation

    Richardson, D. R.; Knapp, C. F.

    1977-01-01

    Preliminary results are presented for a study aimed at a quantitative comparison of microvascular dynamics in second-generation rats reared in a 2-g force field produced by centrifugation with similar data from animals reared in a centrifuge that produced only a 1-g force. It is shown that the pressure distribution in the mesenteric microvasculature of the second generation of rats reared in a 2-g environment, as well as the animals' blood pressure response to epinephrine, are significantly different compared to their 1-g counterparts. In particular, 1-g and 2-g chronic centrifugation enhances the arterial blood pressure, and the 2-g force field attenuates the pressor effects of norepinephrine.

  9. Centrifuge facilities at Technical University of 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....

  10. Empirical Design Considerations for Industrial Centrifugal Compressors

    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.

  11. Decontamination of nuclear fuels with centrifugal separation

    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

  12. Decontamination of nuclear fuels with centrifugal separation

    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)

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

    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.

  14. CFD simulation of centrifugal cells washers.

    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.

  15. Testing of pyrochemical centrifugal contactors

    Chow, L.S.; Carls, E.L.; Basco, J.K.; Johnson, T.R.

    1996-01-01

    A centrifugal contactor that performs oxidation and reduction exchange reactions between molten metals and salts at 500 degrees Centigrade has been tested successfully at Argonne National Laboratory (ANL). The design is based on contactors for aqueous- organic systems operation near room temperature. In tests to demonstrate the performance of the pyrocontactor, cadmium and LICl-KCl eutectic salt were the immiscible solvent phases, and rare earths were the distributing solutes. The tests showed that the pyrocontactor mixed and separated the phases well, with stage efficiencies approaching 99% at rotor speeds near 2700 rpm. The contactor ran smoothly and reliably over the entire range of speeds that was tested

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

    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®

  17. Solid deuterium centrifuge pellet injector

    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

  18. Solid deuterium centrifuge pellet injector

    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

  19. Rotor for a pyrolysis centrifuge reactor

    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....

  20. Detection methods for centrifugal microfluidic platforms

    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....

  1. Isotopic enrichment in a plasma centrifuge

    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

  2. Centrifuge modelling of offshore monopile foundation

    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...

  3. Modelling of hydrothermal characteristics of centrifugal nozzles

    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

  4. Astronaut Gordon Cooper in centrifuge for tests

    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.

  5. High frequency dynamics in centrifugal compressors

    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

  6. Gas-centrifuge unit and centrifugal process for isotope separation

    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

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

    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. Progress in ultra-centrifuge enrichment technology

    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)

  9. The analysis on centrifugal compressor rotating stall

    Kim, Ji Hwan; Kim, Kwang Ho; Shin, You Hwan

    2003-01-01

    In the present study, the performance characteristics and the number of stall cell during rotating stall of a centrifugal air compressor were experimentally investigated. Rotating stall in the vaneless diffuser were investigated by measuring unsteady pressure fluctuations at several different diffuser radius using a high frequency pressure transducer. The number of stall cell and their rotational speeds are distinctive features of the rotating stall phenomenon. The present study is mainly forced on the analysis for the stall cell number and its propagation speed unstable operating region of the compressor. The interpretation method of visualization is based on the pressure distribution in the circumference pressure fields while plotting the pressure and its harmonics variations in time in polar coordinates. To obtain the visualize the existence rotating stall, auto-correlation function and the frequency spectra of the pressure fluctuations were measured at r/r2=1.52. When the flow coefficient is lower than 0.150, the static pressure at impeller inlet is higher than that at inlet duct of the compressor. And the flow coefficient is lower than 0.086, several stall cell groups of discrete frequencies are observed

  10. Directly observed reversible shape changes and hemoglobin stratification during centrifugation of human and Amphiuma red blood cells.

    Hoffman, Joseph F; Inoué, Shinya

    2006-02-21

    This paper describes changes that occur in human and Amphiuma red blood cells observed during centrifugation with a special microscope. Dilute suspensions of cells were layered, in a centrifuge chamber, above an osmotically matched dense solution, containing Nycodenz, Ficoll, or Percoll (Pharmacia) that formed a density gradient that allowed the cells to slowly settle to an equilibrium position. Biconcave human red blood cells moved downward at low forces with minimum wobble. The cells oriented vertically when the force field was increased and Hb sedimented as the lower part of each cell became bulged and assumed a "bag-like" shape. The upper centripetal portion of the cell became thinner and remained biconcave. These changes occurred rapidly and were completely reversible upon lowering the centrifugal force. Bag-shaped cells, upon touching red cells in rouleau, immediately reverted to biconcave disks as they flipped onto a stack. Amphiuma red cells displayed a different type of reversible stratification and deformation at high force fields. Here the cells became stretched, with the nucleus now moving centrifugally, the Hb moving centripetally, and the bottom of the cells becoming thinner and clear. Nevertheless, the distribution of the marginal bands at the cells' rim was unchanged. We conclude that centrifugation, per se, while changing a red cell's shape and the distribution of its intracellular constituents, does so in a completely reversible manner. Centrifugation of red cells harboring altered or missing structural elements could provide information on shape determinants that are still unexplained.

  11. Centrifugal vacuum casting for fuel cladding tube blanks

    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

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

    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.)

  13. Simulated stand tests and centrifuge training to prevent orthostatic intolerance on Earth, moon, and Mars.

    Coats, Brandon W; Sharp, M Keith

    2010-03-01

    One proposed method to overcome postflight orthostatic intolerance is for astronauts to undergo inflight centrifugation. Cardiovascular responses were compared between centrifuge and gravitational conditions using a seven-compartment cardiovascular model. Vascular resistance, heart rate, and stroke volume values were adopted from literature, while compartmental volumes and compliances were derived from impedance plethysmography of subjects (n=8) riding on a centrifuge. Three different models were developed to represent the typical male subject who completed a 10-min postflight stand test ("male finisher"), "non-finishing male" and "female" (all non-finishers). A sensitivity analysis found that both cardiac output and arterial pressure were most sensitive to total blood volume. Simulated stand tests showed that female astronauts were more susceptible to orthostatic intolerance due to lower initial blood pressure and higher pressure threshold for presyncope. Rates of blood volume loss by capillary filtration were found to be equivalent in female and male non-finishers, but four times smaller in male finishers. For equivalent times to presyncope during centrifugation as those during constant gravity, lower G forces at the level of the heart were required. Centrifuge G levels to match other cardiovascular parameters varied depending on the parameter, centrifuge arm length, and the gravity level being matched.

  14. Analogue scale modelling of extensional tectonic processes using a large state-of-the-art centrifuge

    Park, Heon-Joon; Lee, Changyeol

    2017-04-01

    Analogue scale modelling of extensional tectonic processes such as rifting and basin opening has been numerously conducted. Among the controlling factors, gravitational acceleration (g) on the scale models was regarded as a constant (Earth's gravity) in the most of the analogue model studies, and only a few model studies considered larger gravitational acceleration by using a centrifuge (an apparatus generating large centrifugal force by rotating the model at a high speed). Although analogue models using a centrifuge allow large scale-down and accelerated deformation that is derived by density differences such as salt diapir, the possible model size is mostly limited up to 10 cm. A state-of-the-art centrifuge installed at the KOCED Geotechnical Centrifuge Testing Center, Korea Advanced Institute of Science and Technology (KAIST) allows a large surface area of the scale-models up to 70 by 70 cm under the maximum capacity of 240 g-tons. Using the centrifuge, we will conduct analogue scale modelling of the extensional tectonic processes such as opening of the back-arc basin. Acknowledgement This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (grant number 2014R1A6A3A04056405).

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

    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.

  16. Centrifugal and axial compressor control

    McMillan, Gregory K

    2009-01-01

    Control engineers, mechanical engineers and mechanical technicians will learn how to select the proper control systems for axial and centrifugal compressors for proper throughput and surge control, with a particular emphasis on surge control. Readers will learn to understand the importance of transmitter speed, digital controller sample time, and control valve stroking time in helping to prevent surge. Engineers and technicians will find this book to be a highly valuable guide on compressor control schemes and the importance of mitigating costly and sometimes catastrophic surge problems. It can be used as a self-tutorial guide or in the classroom with the book's helpful end-of-chapter questions and exercises and sections for keeping notes.

  17. Acute spinal injury after centrifuge training in asymptomatic fighter pilots.

    Kang, Kyung-Wook; Shin, Young Ho; Kang, Seungcheol

    2015-04-01

    Many countries have hypergravity training centers using centrifuges for pilots to cope with a high gravity (G) environment. The high G training carries potential risk for the development of spinal injury. However, no studies evaluated the influence of centrifuge training on the spines of asymptomatic fighter pilots on a large scale. Study subjects were 991 male fighter pilots with high G training at one institution. Subject variables included information about physical characteristics, flight hours of pilots prior to the training, and G force exposure related factors during training. The two dependent variables were whether the pilots developed acute spinal injury after training and the severity of the injury (major/minor). The incidence of acute spinal injury after high G training was 2.3% (23 of 991 subjects). There were 19 subjects who developed minor injury and 4 subjects who developed a herniated intervertebral disc, which is considered a major injury. In multivariate analysis, only the magnitude of G force during training was significantly related to the development of acute spinal injury. However, there was no significant factor related to the severity of the injury. These results suggest that high G training could cause negative effects on fighter pilots' spines. The magnitude of G force during training seemed to be the most significant factor affecting the occurrence of acute spinal injury.

  18. Cantilever Beam Natural Frequencies in Centrifugal Inertia Field

    Jivkov, V. S.; Zahariev, E. V.

    2018-03-01

    In the advanced mechanical science the well known fact is that the gravity influences on the natural frequencies and modes even for the vertical structures and pillars. But, the condition that should be fulfilled in order for the gravity to be taken into account is connected with the ration between the gravity value and the geometrical cross section inertia. The gravity is related to the earth acceleration but for moving structures there exist many other acceleration exaggerated forces and such are forces caused by the centrifugal accelerations. Large rotating structures, as wind power generators, chopper wings, large antennas and radars, unfolding space structures and many others are such examples. It is expected, that acceleration based forces influence on the structure modal and frequency properties, which is a subject of the present investigations. In the paper, rotating beams are subject to investigations and modal and frequency analysis is carried out. Analytical dependences for the natural resonances are derived and their dependences on the angular velocity and centrifugal accelerations are derived. Several examples of large rotating beams with different orientations of the rotating shaft are presented. Numerical experiments are conducted. Time histories of the beam tip deflections, that depict the beam oscillations are presented.

  19. Flow visualization in models of high speed centrifugal separators

    Lagerstedt, T.; Nabo, O.

    1987-01-01

    The modern centrifugal separator is a fluid machine where the high ''G'' forces set up by rotation are utilized to separate phases of different densities. The fluid dynamics of the separator is complex and poorly known. Hundred years of (practical) experience has, however, turned the separator into an efficient machine. The present report shows how straight forward visualization experiments in model rigs provide valuable information on the flow inside the separator. The report concentrates on describing the flow between the closely spaced discs in a separator disc stack

  20. Centrifuge-operated specimen staining method and apparatus

    Clarke, Mark S. F. (Inventor); Feeback, Daniel L. (Inventor)

    1999-01-01

    A method of staining preselected, mounted specimens of either biological or nonbiological material enclosed within a staining chamber where the liquid staining reagents are applied and removed from the staining chamber using hypergravity as the propelling force. In the preferred embodiment, a spacecraft-operated centrifuge and method of diagnosing biological specimens while in orbit, characterized by hermetically sealing a shell assembly. The assembly contains slide stain apparatus with computer control therefor, the operative effect of which is to overcome microgravity, for example on board an International Space Station.

  1. Centrifuge workers study. Phase II, completion report

    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.

  2. Centrifuge workers study. Phase II, completion report

    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

  3. Review of the gas centrifuge until 1962. Part I: Principles of separation physics

    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

  4. Socioeconomic effects of the DOE Gas Centrifuge Enrichment Plant. Volume 1: methodology and analysis

    1979-01-01

    The socioeconomic effects of the Gas Centrifuge Enrichment Plant being built in Portsmouth, Ohio were studied. Chapters are devoted to labor force, housing, population changes, economic impact, method for analysis of services, analysis of service impacts, schools, and local government finance

  5. Plasma instability of a vacuum arc centrifuge

    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

  6. Two-Dimensional Computational Flow Analysis and Frictional Characteristics Model for Red Blood Cell under Inclined Centrifuge Microscopy

    Funamoto, Kenichi; Hayase, Toshiyuki; Shirai, Atsushi

    Simplified two-dimensional flow analysis is performed in order to simulate frictional characteristics measurement of red blood cells moving on a glass plate in a medium with an inclined centrifuge microscope. Computation under various conditions reveals the influences of parameters on lift, drag, and moment acting on a red blood cell. Among these forces, lift appears only when the cell is longitudinally asymmetric. By considering the balance of forces, the frictional characteristics of the red blood cell are modeled as the sum of Coulomb friction and viscous drag. The model describes the possibility that the red blood cell deforms to expand in the front side in response to the inclined centrifugal force. When velocity exceeds some critical value, the lift overcomes the normal centrifugal force component, and the thickness of the plasma layer between the cell and the glass plate increases from the initial value of the plasma protein thickness.

  7. Inertial particle focusing in serpentine channels on a centrifugal platform

    Shamloo, Amir; Mashhadian, Ali

    2018-01-01

    Inertial particle focusing as a powerful passive method is widely used in diagnostic test devices. It is common to use a curved channel in this approach to achieve particle focusing through balancing of the secondary flow drag force and the inertial lift force. Here, we present a focusing device on a disk based on the interaction of secondary flow drag force, inertial lift force, and centrifugal forces to focus particles. By choosing a channel whose cross section has a low aspect ratio, the mixing effect of the secondary flow becomes negligible. To calculate inertial lift force, which is exerted on the particle from the fluid, the interaction between the fluid and particle is investigated accurately through implementation of 3D Direct Numerical Solution (DNS) method. The particle focusing in three serpentine channels with different corner angles of 75°, 85°, and 90° is investigated for three polystyrene particles with diameters of 8 μm, 9.9 μm, and 13 μm. To show the simulation reliability, the results obtained from the simulations of two examples, namely, particle focusing and centrifugal platform, are verified against experimental counterparts. The effects of angular velocity of disk on the fluid velocity and on the focusing parameters are studied. Fluid velocity in a channel with corner angle of 75° is greater than two other channels. Furthermore, the particle equilibrium positions at the cross section of channel are obtained at the outlet. There are two equilibrium positions located at the centers of the long walls. Finally, the effect of particle density on the focusing length is investigated. A particle with a higher density and larger diameter is focused in a shorter length of the channel compared to its counterpart with a lower density and shorter diameter. The channel with a corner angle of 90° has better focusing efficiency compared to other channels. This design focuses particles without using any pump or sheath flow. Inertial particle focusing

  8. Some engineering considerations when designing centrifuge enrichment plants

    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.)

  9. Safety aspects of gas centrifuge enrichment plants

    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

  10. Thermal analysis of a gas centrifuge

    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)

  11. Gas centrifuge with driving motor

    Dancy, Jr., William H.

    1976-01-01

    1. A centrifuge for separating gaseous constituents of different masses comprising a vertical tubular rotor, means for introducing a gas mixture of different masses into said rotor and means for removing at least one of the gas components from the rotor, a first bearing means supporting said rotor at one end for rotational movement, a support, a damping bearing mounted on said support, a shaft fixed to said rotor at the opposite end and mechanically connecting said rotor to said damping bearing, a cup-shaped tube of electrically conductive, non-magnetic material in coaxial relationship with said shaft, the open end of said tube extending away from said rotor and the closed end of said tube being directly secured to the adjacent end of the rotor, an annular core of magnetic material fixedly mounted on said support so as to be disposed within said tube and around said shaft, and a second annular magnetic core with coils arranged thereon to receive polyphase current to produce a rotating magnetic field traversing the circumference of said tube, fixedly mounted on said support so as to surround said tube, the size of said first annular core and said second annular core being such as to permit limited radial displacement of said shaft and said tube.

  12. Gas centrifuge with driving motor

    Dancy, W.H. Jr.

    1976-01-01

    A centrifuge for separating gaseous constituents of different masses consists of: a vertical tubular rotor; means for introducing a gas mixture of different masses into the rotor and means for removing at least one of the gas components from the rotor; a first bearing means supporing the rotor at one end; a support; a damping bearing mounted on the support; a shaft fixed to the rotor at the opposite end and mechanically connecting the rotor to the damping bearing; a cup-shaped tube of electrically conductive, non-magnetic material in coaxial relationship with the shaft, the open end of the tube extending away from the rotor, and the closed end of the tube being directly secured to the adjacent end of the rotor; an annular core of magnetic material fixedly mounted on the support so as to be disposed within the tube and around the shaft; and a second annular magnetic core with coils to receive polyphase current to produce a rotating magnetic field traversing the circumference of the tube, fixedly mounted on the support so as to surround the tube, the size of first and the second annular core being such as to permit limited radial displacement of the shaft and the tube

  13. Two-Stage Centrifugal Fan

    Converse, David

    2011-01-01

    Fan designs are often constrained by envelope, rotational speed, weight, and power. Aerodynamic performance and motor electrical performance are heavily influenced by rotational speed. The fan used in this work is at a practical limit for rotational speed due to motor performance characteristics, and there is no more space available in the packaging for a larger fan. The pressure rise requirements keep growing. The way to ordinarily accommodate a higher DP is to spin faster or grow the fan rotor diameter. The invention is to put two radially oriented stages on a single disk. Flow enters the first stage from the center; energy is imparted to the flow in the first stage blades, the flow is redirected some amount opposite to the direction of rotation in the fixed stators, and more energy is imparted to the flow in the second- stage blades. Without increasing either rotational speed or disk diameter, it is believed that as much as 50 percent more DP can be achieved with this design than with an ordinary, single-stage centrifugal design. This invention is useful primarily for fans having relatively low flow rates with relatively high pressure rise requirements.

  14. Achieving an ever-improving centrifuge

    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)

  15. Centrifuge modelling of contaminant transport processes

    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...

  16. Horizontal vibrations of piles in a centrifuge

    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

  17. Quantum fictitious forces

    Bialynicki-Birula, I; Cirone, M.A.; Dahl, Jens Peder

    2002-01-01

    We present Heisenberg's equation of motion for the radial variable of a free non-relativistic particle in D dimensions. The resulting radial force consists of three contributions: (i) the quantum fictitious force which is either attractive or repulsive depending on the number of dimensions, (ii......) a singular quantum force located at the origin, and (iii) the centrifugal force associated with non-vanishing angular momentum. Moreover, we use Heisenberg's uncertainty relation to introduce a lower bound for the kinetic energy of an ensemble of neutral particles. This bound is quadratic in the number...... of atoms and can be traced back to the repulsive quantum fictitious potential. All three forces arise for a free particle: "Force without force"....

  18. Centrifuge modelling of lateral displacement of buried pipelines; Modelagem fisica centrifuga de flambagem lateral de dutos

    Oliveira, Jose Renato Moreira da Silva de; Almeida, Marcio de Souza Soares de; Marques, Maria Esther Soares; Almeida, Maria Cascao Ferreira de [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE); Costa, Alvaro Maia da [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2003-07-01

    This work discusses soil-structure interaction applied to the buckling phenomena of buried pipelines subjected to heated oil flow. A set of physical modelling tests on lateral buckling of pipelines buried on soft clay is presented using COPPE/UFRJ geotechnical centrifuge. A 1:30 pipeline model was moved side ward through a soft clay layer during centrifuge flight, varying the burial depth, in order to simulate the lateral buckling in plane strain condition. The results show different behaviour concerning horizontal and vertical forces measured at pipeline level due to soil reaction. (author)

  19. A Turbidity Test Based Centrifugal Microfluidics Diagnostic System for Simultaneous Detection of HBV, HCV, and CMV

    Hung-Cheng Chang

    2015-01-01

    Full Text Available This paper presents a LAMP- (loop-mediated isothermal amplification- based lab-on-disk optical system that allows the simultaneous detection of hepatitis B virus, hepatitis C virus, and cytomegalovirus. The various flow stages are controlled in the proposed system using different balance among centrifugal pumping, Coriolis pumping, and the capillary force. We have implemented a servo system for positioning and speed control for the heating and centrifugal pumping. We have also successfully employed a polymer light-emitting diode section for turbidity detection. The easy-to-use one-click system can perform diagnostics in less than 1 hour.

  20. 76 FR 50767 - In the Matter of USEC Inc., American Centrifuge Lead Cascade Facility, and American Centrifuge...

    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...

  1. Separation of uranium isotopes by gas centrifugation

    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. Enrichment technology. Dependable vendor of gas centrifuges

    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.)

  3. Nonisentropic Nonsteady Liquid Flow with Centrifugal, Gravitational, and Dissipative Forces

    Sidransky, Fred

    1966-01-01

    The method of characteristics is used to present general compatibility relations for nonsteady liquid flow or water-hammer theory which permit the investigation of the dynamics of the flow under diverse conditions...

  4. Dynamic response of high speed centrifuge for reprocessing plant

    Rajput, Gaurav; Satish Kumar, V.; Selvaraj, T.; Ananda Rao, S.M.; Ravisankar, A.

    2012-01-01

    The standard for balancing the rotating bowl describes only the details about the selection of balance quality grade and the permissible residual unbalance for different operating speeds. This paper presents the effects of unbalance on the rotating bowl of high speed centrifuge used in reprocessing of spent nuclear fuel. In this study, the residual unbalance is evaluated for different recommended balancing grades in accordance with the ISO 1940. This unbalance mass generates dynamic force which acts on the rotor. The dynamic response of the rotor like displacements and stresses under this dynamic force are studied by numerical simulation. Finally, the effect of residual unbalance on the rotating bowl performance for different balancing grades is discussed. The experimental measurements are also carried out for the case of G 1.0 grade balanced rotating bowl to validate the resonance frequency as well as vibration amplitudes. (author)

  5. Systems approach used in the Gas Centrifuge Enrichment Plant

    Rooks, W.A. Jr.

    1982-01-01

    A requirement exists for effective and efficient transfer of technical knowledge from the design engineering team to the production work force. Performance-Based Training (PBT) is a systematic approach to the design, development, and implementation of technical training. This approach has been successfully used by the US Armed Forces, industry, and other organizations. The advantages of the PBT approach are: cost-effectiveness (lowest life-cycle training cost), learning effectiveness, reduced implementation time, and ease of administration. The PBT process comprises five distinctive and rigorous phases: Analysis of Job Performance, Design of Instructional Strategy, Development of Training Materials and Instructional Media, Validation of Materials and Media, and Implementation of the Instructional Program. Examples from the Gas Centrifuge Enrichment Plant (GCEP) are used to illustrate the application of PBT

  6. Systems approach used in the Gas Centrifuge Enrichment Plant

    Rooks, W.A. Jr.

    1982-01-01

    A requirement exists for effective and efficient transfer of technical knowledge from the design engineering team to the production work force. Performance-Based Training (PBT) is a systematic approach to the design, development, and implementation of technical training. This approach has been successfully used by the US Armed Forces, industry, and other organizations. The advantages of the PBT approach are: cost-effectiveness (lowest life-cycle training cost), learning effectiveness, reduced implementation time, and ease of administration. The PBT process comprises five distinctive and rigorous phases: Analysis of Job Performance, Design of Instructional Strategy, Development of Training Materials and Instructional Media, Validation of Materials and Media, and Implementation of the Instructional Program. Examples from the Gas Centrifuge Enrichment Plant (GCEP) are used to illustrate the application of PBT.

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

    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

  8. Centrifugation protocols: tests to determine optimal lithium heparin and citrate plasma sample quality.

    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.

  9. Centrifugal fragmentation of a dinuclear system in the process of its evolution toward a compound nucleus

    Volkov, V. V.

    2007-01-01

    The centrifugal fragmentation of a dinuclear system in the process of evolution toward a compound nucleus is examined. If the angular momentum in the collision of primary nuclei is quite high, centrifugal forces become dominant at the final stage of the evolution of the dinuclear system formed, causing the decay of this dinuclear system to two strongly asymmetric nuclear fragments. Experimental data in which this specific nuclear process manifests itself are presented. Centrifugal fragmentation makes it possible to reveal the cluster facet of the evolution of a dinuclear system toward a compound nucleus. The possibility of this fragmentation process is a logical consequence of the concept of a dinuclear system for the complete fusion of nuclei

  10. Steady state behavior of rotating plasmas in a vacuum-arc centrifuge

    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)

  11. Steady state behavior of rotating plasmas in a vacuum-arc centrifuge

    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

  12. Theoretical considerations in solid bowl centrifugation

    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

  13. Centrifugation assay for measuring adhesion of serially passaged bovine chondrocytes to polystyrene surfaces.

    Kaplan, David S; Hitchins, Victoria M; Vegella, Thomas J; Malinauskas, Richard A; Ferlin, Kimberly M; Fisher, John P; Frondoza, Carmelita G

    2012-07-01

    A major obstacle in chondrocyte-based therapy for cartilage repair is the limited availability of cells that maintain their original phenotype. Propagation of chondrocytes as monolayer cultures on polystyrene surfaces is used extensively for amplifying cell numbers. However, chondrocytes undergo a phenotypic shift when propagated in this manner and display characteristics of more adherent fibroblastic cells. Little information is available about the effect of this phenotypic shift on cellular adhesion properties. We evaluated changes in adhesion property as bovine chondrocytes were serially propagated up to five passages in monolayer culture using a centrifugation cell adhesion assay, which was based on counting of cells before and after being exposed to centrifugal dislodgement forces of 120 and 350 g. Chondrocytes proliferated well in a monolayer culture with doubling times of 2-3 days, but they appeared more fibroblastic and exhibited elongated cell morphology with continued passage. The centrifugation cell adhesion assay showed that chondrocytes became more adhesive with passage as the percentage of adherent cells after centrifugation increased and was not statistically different from the adhesion of the fibroblast cell line, L929, starting at passage 3. This increased adhesiveness correlated with a shift to a fibroblastic morphology and increased collagen I mRNA expression starting at passage 2. Our findings indicate that the centrifugation cell adhesion assay may serve as a reproducible tool to track alterations in chondrocyte phenotype during their extended propagation in culture.

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

    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.

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

    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

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

    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

  17. Quantum anticentrifugal force

    Cirone, M.A.; Schleich, W.P.; Straub, F.; Rzazewski, K.; Wheeler, J.A.

    2002-01-01

    In a two-dimensional world, a free quantum particle of vanishing angular momentum experiences an attractive force. This force originates from a modification of the classical centrifugal force due to the wave nature of the particle. For positive energies the quantum anticentrifugal force manifests itself in a bunching of the nodes of the energy wave functions towards the origin. For negative energies this force is sufficient to create a bound state in a two-dimensional δ-function potential. In a counterintuitive way, the attractive force pushes the particle away from the location of the δ-function potential. As a consequence, the particle is localized in a band-shaped domain around the origin

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

    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.)

  19. Liquid centrifugation for nuclear waste partitioning

    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

  20. Centrifugal acceleration in the magnetotail lobes

    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.

  1. Forces in general relativity

    Ridgely, Charles T

    2010-01-01

    Many textbooks dealing with general relativity do not demonstrate the derivation of forces in enough detail. The analyses presented herein demonstrate straightforward methods for computing forces by way of general relativity. Covariant divergence of the stress-energy-momentum tensor is used to derive a general expression of the force experienced by an observer in general coordinates. The general force is then applied to the local co-moving coordinate system of a uniformly accelerating observer, leading to an expression of the inertial force experienced by the observer. Next, applying the general force in Schwarzschild coordinates is shown to lead to familiar expressions of the gravitational force. As a more complex demonstration, the general force is applied to an observer in Boyer-Lindquist coordinates near a rotating, Kerr black hole. It is then shown that when the angular momentum of the black hole goes to zero, the force on the observer reduces to the force on an observer held stationary in Schwarzschild coordinates. As a final consideration, the force on an observer moving in rotating coordinates is derived. Expressing the force in terms of Christoffel symbols in rotating coordinates leads to familiar expressions of the centrifugal and Coriolis forces on the observer. It is envisioned that the techniques presented herein will be most useful to graduate level students, as well as those undergraduate students having experience with general relativity and tensor analysis.

  2. Probing molecular potentials with an optical centrifuge

    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.

  3. A centrifuge CO2 pellet cleaning system

    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

  4. Centrifugal compressor design for electrically assisted boost

    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

  5. High Efficiency Centrifugal Compressor for Rotorcraft Applications

    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.

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

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

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

  7. Formation of thin film like assembly of exfoliated C3N4 nanoflakes by solvent non-evaporative method using centrifuge

    Tejasvi, Ravi; Basu, Suddhasatwa

    2017-12-01

    A simple method for depositing a thin film of nanomaterial on a substrate using centrifugation technique has been developed, whereby solvent evaporation is prevented and solvent reuse is possible. The centrifuge technique of deposition yields uniform, smooth thin film irrespective of substrate surface texture. The deposited TiO2/eC3N4 film studied, through field emission scanning electron microscope, atomic force microscope, and optical surface profilometer, shows variation in surface roughness on the basis of centrifugation speeds. Initially film coverage improves and surface roughness decreases with the increase in rpm of the centrifuge and the surface roughness slightly increases with further increase in rpm. The photoelectrochemical studies of TiO2/eC3N4 films suggest that the centrifuge technique forms better heterojunctions compared to that by spin coating technique leading to enhanced photoelectrochemical water splitting.

  8. Compound drum for a centrifugal separator

    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

  9. The commercial role for centrifuge enrichment

    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)

  10. Centrifugal compressor design options for small turbochargers

    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)

  11. Wave-Driven Rotation In Centrifugal Mirrors

    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.

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

    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...

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

    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.)

  14. Numerical and experimental study on the steady cone-jet mode of electro-centrifugal spinning

    Hashemi, Ali Reza; Pishevar, Ahmad Reza; Valipouri, Afsaneh; Pǎrǎu, Emilian I.

    2018-01-01

    This study focuses on a numerical investigation of an initial stable jet through the air-sealed electro-centrifugal spinning process, which is known as a viable method for the mass production of nanofibers. A liquid jet undergoing electric and centrifugal forces, as well as other forces, first travels in a stable trajectory and then goes through an unstable curled path to the collector. In numerical modeling, hydrodynamic equations have been solved using the perturbation method—and the boundary integral method has been implemented to efficiently solve the electric potential equation. Hydrodynamic equations have been coupled with the electric field using stress boundary conditions at the fluid-fluid interface. Perturbation equations were discretized by a second order finite difference method, and the Newton method was implemented to solve the discretized non-linear system. Also, the boundary element method was utilized to solve electrostatic equations. In the theoretical study, the fluid was described as a leaky dielectric with charges only on the surface of the jet traveling in dielectric air. The effect of the electric field induced around the nozzle tip on the jet instability and trajectory deviation was also experimentally studied through plate-plate geometry as well as point-plate geometry. It was numerically found that the centrifugal force prevails on electric force by increasing the rotational speed. Therefore, the alteration of the applied voltage does not significantly affect the jet thinning profile or the jet trajectory.

  15. Rhie-Chow interpolation in strong centrifugal fields

    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.

  16. Direct Monte-Carlo Siumulations In a Gas Centrifuge

    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...

  17. Design of Structural Parameters for Centrifugal Elevator Overspeed Governors

    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. Centrifugal Separation Device Based on Two-Layer Laminar Flow in Microchannels for High-Throughput and Continuous Blood Cell/Plasma Separation

    Taizo Kobayashi,; Taisuke Funamoto,; Makoto Hosaka,; Satoshi Konishi,

    2010-07-01

    This paper presents a novel type of centrifugation device that is based on the two-layer laminar flow in micro flow channels for continuous blood cell/plasma separation. We propose to rotate the flow channels which are arranged along the circumference around the rotational axis. Downsizing the channel width reduced both the cell sedimentation time and the required centrifugal force, because the channel width corresponds to the centrifugal sedimentation length. First, plasma and cells were continuously extracted from pig blood in each of the branch channels using a milled acrylic prototype device (channel width = 800 μm, volume = 150 μl). Next, the relationship between the channel width (125, 250, and 500 μm) and the sedimentation time taken for various centrifugal forces (2.3, 9, 36, and 145 G) was evaluated using the downsized microchannels fabricated by hot-embossing and thermal bonding technologies. Using downsized microchannels with a width of 125 μm successfully reduced the sedimentation time to 85 s as compared to the sedimentation time of 270 s for a channel of a width of 500 μm, when a centrifugal force of 2.3 G was applied. The use of the proposed device did not result in obvious hemolysis at the centrifugal forces lower than 335 G.

  19. Effect of centrifuge test on blood serum lipids index of cadet pilots.

    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.

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

    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.

  1. Centrifugal Pump Experiment for Chemical Engineering Undergraduates

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

    2012-01-01

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

  2. Centrifuge in space fluid flow visualization experiment

    Arnold, William A.; Wilcox, William R.; Regel, Liya L.; Dunbar, Bonnie J.

    1993-01-01

    A prototype flow visualization system is constructed to examine buoyancy driven flows during centrifugation in space. An axial density gradient is formed by imposing a thermal gradient between the two ends of the test cell. Numerical computations for this geometry showed that the Prandtl number plays a limited part in determining the flow.

  3. Annular centrifugal contactors for TRPO process test

    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.

  4. Preparation of targets by a centrifugal method

    Richaud, J.P.

    1979-01-01

    For β and γ in-beam spectroscopy measurements, a centrifugal technique has been developed to produce targets of powdered isotopic materials. Plastic or metallic backings and suitable organic solutions are described. With this method, targets in the range 1-50 mg/cm 2 have been obtained. (orig.)

  5. Pressure distribution in centrifugal dental casting.

    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.

  6. Gas centrifuge bibliography 1983-1986

    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.)

  7. Fault Detection and Isolation in Centrifugal Pumps

    Kallesøe, Carsten

    Centrifugal pumps are used in a variety of different applications, such as water supply, wastewater, and different industrial applications. Some pump installations are crucial for the applications to work. Failures can lead to substantial economic losses and can influence the life of many people...

  8. A high pressure centrifugal oxygen compressor

    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

  9. Positive feedback stabilization of centrifugal compressor surge

    Willems, Frank; Heemels, W.P.M.H.; de Jager, Bram; Stoorvogel, Antonie Arij

    Stable operation of axial and centrifugal compressors is limited towards low mass flows due to the occurrence of surge. The stable operating region can be enlarged by active control. In this study, we use a control valve which is fully closed in the desired operating point and only opens to

  10. Positive feedback stabilization of centrifugal compressor surge

    Willems, F.P.T.; Heemels, W.P.M.H.; Jager, de A.G.; Stoorvogel, A.A.

    2002-01-01

    Stable operation of axial and centrifugal compressors is limited towards low mass flows due to the occurrence of surge. The stable operating region can be enlarged by active control. In this study, we use a control valve which is fully closed in the desired operating point and only opens to

  11. Differential white cell count by centrifugal microfluidics.

    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.

  12. Performance of a centrifugal pump running in inverse mode

    Fernandez, J. [Universidad de Extramadura, Badajoz (Spain). Departamento de Electronica e Ingenieria Electromecanica; Blanco, E.; Parrondo, J. [Oviedo Univ. (Spain). Departamento de Energia; Stickland, M.; Scanlon, T.J. [Strathclyde Univ., Glasgow (United Kingdom). Dept. of Mechanical Engineering

    2004-08-01

    This paper presents the functional characterization of a centrifugal pump used as a turbine. It shows the characteristics of the machine involved at several rotational speeds, comparing the respective flows and heads. In this way, it is possible to observe the influence of the rotational speed on efficiency, as well as obtaining the characteristics at constant head and runaway speed. Also, the forces actuating on the impeller were studied. An uncertainty analysis was made to assess the accuracy of the results. The research results indicate that the turbine characteristics can be predicted to some extent from the pump characteristics, that water flows out of the runner free of swirl flow at the best efficiency point, and that radial stresses are lower than in pump mode. (author)

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

    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

  14. Bacterial Cell Surface Damage Due to Centrifugal Compaction

    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

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

    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)

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

    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.

  17. Synchronization of Budding Yeast by Centrifugal Elutriation.

    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.

  18. Waves in strong centrifugal fields: dissipationless gas

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

    2015-04-01

    Linear waves are investigated in a rotating gas under the condition of strong centrifugal acceleration of the order 106 g realized in gas centrifuges for separation of uranium isotopes. Sound waves split into three families of the waves under these conditions. Dispersion equations are obtained. The characteristics of the waves strongly differ from the conventional sound waves on polarization, velocity of propagation and distribution of energy of the waves in space for two families having frequencies above and below the frequency of the conventional sound waves. The energy of these waves is localized in rarefied region of the gas. The waves of the third family were not specified before. They propagate exactly along the rotational axis with the conventional sound velocity. These waves are polarized only along the rotational axis. Radial and azimuthal motions are not excited. Energy of the waves is concentrated near the wall of the rotor where the density of the gas is largest.

  19. Quasi-conical centrifugal ion trap

    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

  20. Instability of a Vacuum Arc Centrifuge

    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

  1. Separative performance transients in a gas centrifuge

    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

  2. A vibration model for centrifugal contactors

    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.

  3. LMR [liquid metal reactor] centrifugal pump coastdowns

    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. A vibration model for centrifugal contactors

    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

  5. High stability design for new centrifugal compressor

    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.

  6. Meridional Considerations of the Centrifugal Compressor Development

    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.

  7. CENTRIFUGAL VIBRATION TEST OF RC PILE FOUNDATION

    Higuchi, Shunichi; Tsutsumiuchi, Takahiro; Otsuka, Rinna; Ito, Koji; Ejiri, Joji

    It is necessary that nonlinear responses of structures are clarified by soil-structure interaction analysis for the purpose of evaluating the seismic performances of underground structure or foundation structure. In this research, centrifuge shake table tests of reinforced concrete pile foundation installed in the liquefied ground were conducted. Then, finite element analyses for the tests were conducted to confirm an applicability of the analytical method by comparing the experimental results and analytical results.

  8. Analysis of performance for centrifugal steam compressor

    Kang, Seung Hwan; Ryu, Chang Kook; Ko, Han Seo [Sungkyunkwan University, Suwon (Korea, Republic of)

    2016-12-15

    In this study, mean streamline and Computational fluid dynamics (CFD) analyses were performed to investigate the performance of a small centrifugal steam compressor using a latent heat recovery technology. The results from both analysis methods showed good agreement. The compression ratio and efficiency of steam were found to be related with those of air by comparing the compression performances of both gases. Thus, the compression performance of steam could be predicted by the compression performance of air using the developed dimensionless parameters.

  9. Uranium enrichment by centrifuge in Japan

    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

  10. Centrifugal shot blasting. Innovative technology summary report

    1999-07-01

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

  11. Analysis of performance for centrifugal steam compressor

    Kang, Seung Hwan; Ryu, Chang Kook; Ko, Han Seo

    2016-01-01

    In this study, mean streamline and Computational fluid dynamics (CFD) analyses were performed to investigate the performance of a small centrifugal steam compressor using a latent heat recovery technology. The results from both analysis methods showed good agreement. The compression ratio and efficiency of steam were found to be related with those of air by comparing the compression performances of both gases. Thus, the compression performance of steam could be predicted by the compression performance of air using the developed dimensionless parameters

  12. Wave-driven countercurrent plasma centrifuge

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

    2009-11-15

    A method for driving rotation and a countercurrent flow in a fully ionized plasma centrifuge is described. The rotation is produced by radiofrequency waves near the cyclotron resonance. The wave energy is transferred into potential energy in a manner similar to the {alpha} channeling effect. The countercurrent flow may also be driven by radiofrequency waves. By driving both the rotation and the flow pattern using waves instead of electrodes, physical and engineering issues may be avoided.

  13. Wave-driven countercurrent plasma centrifuge

    Fetterman, Abraham J; Fisch, Nathaniel J

    2009-01-01

    A method for driving rotation and a countercurrent flow in a fully ionized plasma centrifuge is described. The rotation is produced by radiofrequency waves near the cyclotron resonance. The wave energy is transferred into potential energy in a manner similar to the α channeling effect. The countercurrent flow may also be driven by radiofrequency waves. By driving both the rotation and the flow pattern using waves instead of electrodes, physical and engineering issues may be avoided.

  14. Wave-driven Countercurrent Plasma Centrifuge

    Fetterman, A.J.; Fisch, N.J.

    2009-01-01

    A method for driving rotation and a countercurrent flow in a fully ionized plasma centrifuge is described. The rotation is produced by radiofrequency waves near the cyclotron resonance. The wave energy is transferred into potential energy in a manner similar to the α channeling effect. The countercurrent flow may also be driven by radiofrequency waves. By driving both the rotation and the flow pattern using waves instead of electrodes, physical and engineering issues may be avoided

  15. Thermally-controlled centrifuge for isotopic separation

    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. Multiple-isotope separation in gas centrifuge

    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

  17. Solvent extraction studies in miniature centrifugal contactors

    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

  18. Environmental applications of the centrifugal fast analyzer

    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

  19. Unsteady flow measurements in centrifugal compressors

    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

  20. Spin doctors: new innovations for centrifugal apheresis.

    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.

  1. Circadian rhythm of leaf movement in Capsicum annuum observed during centrifugation

    Chapman, D. K.; Brown, A. H.; Dahl, A. O.

    1975-01-01

    Plant circadian rhythms of leaf movement in seedlings of the pepper plant (Capsicum annuum L., var. Yolo Wonder) were observed at different g-levels by means of a centrifuge. Except for the chronically imposed g-force all environmental conditions to which the plants were exposed were held constant. The circadian period, rate of change of amplitude of successive oscillations, symmetry of the cycles, and phase of the rhythm all were found not to be significantly correlated with the magnitude of the sustained g-force.

  2. Shunted Piezoelectric Vibration Damping Analysis Including Centrifugal Loading Effects

    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.

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

    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).

  4. The perception of roll tilt in pilots during a simulated coordinated turn in a gondola centrifuge.

    Tribukait, Arne; Grönkvist, Mikael; Eiken, Ola

    2011-05-01

    It has previously been reported that nonpilots underestimate the roll tilt angle after acceleration in a gondola centrifuge. The aim of the present work was to elucidate the significance of flight experience for roll tilt perception based on vestibular information. The subjective visual horizontal (SVH) was measured by means of an adjustable luminous line in darkness. Eight nonpilots (N), nine fighter pilots (F), and eight helicopter pilots (H) underwent two centrifuge runs (2 G, 5 min) heading forward and backward, respectively. The roll position of the gondola (60 degrees at 2 G) was controlled so that the subject was always upright with respect to the gravitoinertial force. Upon acceleration of the centrifuge there was a tilt of the SVH in a direction compensatory to the inclination of the gondola. This tilt was larger in the forward position [N: 17.2 +/- 6.4 degrees, F: 31.2 +/- 16.4 degrees, H: 33.6 +/- 18.2 degrees (means +/- SD)] than in the backward position (N: -5.0 +/- 6.8 degrees, F: -12.2 +/- 17.4 degrees, H: -10.4 +/- 15.4 degrees). In N the tilt declined with time, approaching zero by the end of the 2-G plateau. In the pilots it was significantly larger and did not decline. Flight experience results in an increased ability to perceive the roll tilt during movement along a curved path. That this can be revealed in a centrifuge might suggest that acceleration of the centrifuge constitutes a movement pattern which is similar, from a vestibular point of view, to that of an airplane entering a coordinated turn.

  5. Heat Transfer Coefficient at Cast-Mold Interface During Centrifugal Casting: Calculation of Air Gap

    Bohacek, Jan; Kharicha, Abdellah; Ludwig, Andreas; Wu, Menghuai; Karimi-Sibaki, Ebrahim

    2018-06-01

    During centrifugal casting, the thermal resistance at the cast-mold interface represents a main blockage mechanism for heat transfer. In addition to the refractory coating, an air gap begins to form due to the shrinkage of the casting and the mold expansion, under the continuous influence of strong centrifugal forces. Here, the heat transfer coefficient at the cast-mold interface h has been determined from calculations of the air gap thickness d a based on a plane stress model taking into account thermoelastic stresses, centrifugal forces, plastic deformations, and a temperature-dependent Young's modulus. The numerical approach proposed here is rather novel and tries to offer an alternative to the empirical formulas usually used in numerical simulations for a description of a time-dependent heat transfer coefficient h. Several numerical tests were performed for different coating thicknesses d C, rotation rates Ω, and temperatures of solidus T sol. Results demonstrated that the scenario at the interface is unique for each set of parameters, hindering the possibility of employing empirical formulas without a preceding experiment being performed. Initial values of h are simply equivalent to the ratio of the coating thermal conductivity and its thickness ( 1000 Wm-2 K-1). Later, when the air gap is formed, h drops exponentially to values at least one order of magnitude smaller ( 100 Wm-2 K-1).

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

    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.

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

    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.

  8. Instabilities expected to exist in a gas centrifuge

    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

  9. Orientation of Al3Ti platelets in Al-Al3Ti functionally graded material manufactured by centrifugal method

    Watanabe, Y.; Fukui, Y.

    1997-01-01

    Al-Al 3 Ti functionally graded materials (FGMs) were manufactured by the centrifugal method with a commercial ingot of Al-5 mass% Ti master alloy. The alloy was melted at a liquid/solid coexisting temperature, at which Al 3 Ti remains as a solid, and then it was cast into a thick-walled ring. It was found that the Al-Al 3 Ti functionally graded material can be successfully fabricated by the centrifugal method. It was also found that the volume fraction of the Al 3 Ti can be increased by repetition of the centrifugal method. Since the shape of Al 3 Ti particles in a commercial alloy ingot is that of a platelet, the Al 3 Ti particles are arranged with their platelet planes nearly perpendicular to the radial direction. The orientation effects become stronger when the G number becomes larger. Although the final centrifugal casting was conducted under a very large centrifugal force for the specimen cast three times, the orientation effects were weaker than those in the specimen cast one time. From these observations, it is concluded that the origin of orientation of Al 3 Ti platelets can be attributed to the angular velocity gradient of the melt along the radial direction produced by the difference in the viscosity. (orig.)

  10. Paperfuge: An ultralow-cost, hand-powered paper-centrifuge inspired by the mechanics of a whirligig toy

    Bhamla, M. Saad; Benson, Brandon; Chai, Chew; Katsikis, Georgios; Johri, Aanchal; Prakash, Manu

    From a global-health context, commercial centrifuges are expensive, bulky and electricity-powered, and thus constitute a critical bottleneck in the development of decentralized, battery-free-point-of-care (POC) diagnostic devices. Here, we report an ultralow-cost (20 cents), lightweight (2 g), human-powered paper centrifuge (which we name 'paperfuge') designed on the basis of a theoretical model inspired by the fundamental mechanics of an ancient whirligig (or buzzer toy; 3300 B.C.E). The paperfuge achieves speeds of 125,000 rpm (and equivalent centrifugal forces of 30,000 g), with theoretical limits predicting one million rpm. We demonstrate that the paperfuge can separate pure plasma from whole blood in less than 1.5 minutes, and isolate malaria parasites in 15 minutes. We also show that paperfuge-like centrifugal microfluidic devices can be made of polymethylsiloxane, plastic and 3D-printed polymeric materials. Ultracheap, power-free centrifuges should open up opportunities for POC diagnostics in resource-poor settings.

  11. Magnetorotational and Parker instabilities in magnetized plasma Dean flow as applied to centrifugally confined plasmas

    Huang Yimin; Hassam, A.B.

    2003-01-01

    The ideal magnetohydrodynamics stability of a Dean flow plasma supported against centrifugal forces by an axial magnetic field is studied. Only axisymmetric perturbations are allowed for simplicity. Two distinct but coupled destabilization mechanisms are present: flow shear (magnetorotational instability) and magnetic buoyancy (Parker instability). It is shown that the flow shear alone is likely insufficient to destabilize the plasma, but the magnetic buoyancy instability could occur. For a high Mach number (M S ), high Alfven Mach number (M A ) system with M S M A > or approx. πR/a (R/a is the aspect ratio), the Parker instability is unstable for long axial wavelength modes. Implications for the centrifugal confinement approach to magnetic fusion are also discussed

  12. Centrifugal mass separation in rotating plasmas produced by a coaxial plasma gun

    Ikehata, T.; Suzuki, M.; Tanabe, T.; Mase, H.

    1989-01-01

    Rotating Cu/Zn plasmas produced by a coaxial plasma gun have been applied to plasma centrifuge. A separation factor of up to 10 is measured over a radius of 4 cm when a current of 13 kA and an axial magnetic field of 2.5 kG are applied. Plasma parameters are: rotation frequency ω=1.1x10 6 rad/s, density n∼10 15 cm -3 , and ion temperature T i =10 eV. The separation factor of 2 is attained even in the plasma core where the density is higher than one-half of the peak value. This is attributed to the fact that a strong centrifugal force forms a hollow density profile which gives the density peak at a radius of 2 cm

  13. Design and Analysis of a Novel Centrifugal Braking Device for a Mechanical Antilock Braking System.

    Yang, Cheng-Ping; Yang, Ming-Shien; Liu, Tyng

    2015-06-01

    A new concept for a mechanical antilock braking system (ABS) with a centrifugal braking device (CBD), termed a centrifugal ABS (C-ABS), is presented and developed in this paper. This new CBD functions as a brake in which the output braking torque adjusts itself depending on the speed of the output rotation. First, the structure and mechanical models of the entire braking system are introduced and established. Second, a numerical computer program for simulating the operation of the system is developed. The characteristics of the system can be easily identified and can be designed with better performance by using this program to studying the effects of different design parameters. Finally, the difference in the braking performance between the C-ABS and the braking system with or without a traditional ABS is discussed. The simulation results indicate that the C-ABS can prevent the wheel from locking even if excessive operating force is provided while still maintaining acceptable braking performance.

  14. Numerical Calculation of the Swirling Flow in a Centrifugal Compressor Volute

    Seong, Seon Mo; Kang, Shin Hyoung; Cho, Kyung Seok; Kim, Woo June

    2007-01-01

    Flows in the centrifugal compressor volute with circular cross section are numerically investigated. The computational grid for the calculation utilized a multi-block arrangement to form a butterfly grid and flow calculations are performed using commercial CFD software, CFX-TASCflow. The centrifugal compressor of this study has axial diffuser after radial diffuser because of the shape of inlet duct and installation constraints. Due to this feature the swirling flow pattern is different from the other investigations. The flow inside volute is very complex and three dimensional with strong vortex and recirculation through volute tongue. The calculation results show circumferential variations of the swirl and through flow velocity and pressure distribution. The mechanism deciding flow structure is explained by considering the force balance in volute cross section. And static pressure recovery and total pressure loss are estimated from the calculated results and compared with Japikse model

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

    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

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

    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

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

    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.

  18. Separative power of an optimised concurrent gas centrifuge

    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.

  19. The gas centrifuge, uranium enrichment and nuclear proliferation

    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)

  20. Characteristics of centrifugal rapid contactor, (3)

    Nakanishi, Mitsuo; Hirayama, Hiroshi; Takasu, Nobuyuki; Takeda, Hiroshi; Hoshino, Tadaya

    1979-01-01

    Organic solvent yields the degradation product as a result of irradiation, in the extraction process of spent fuel reprocessing. The development of a centrifugal rapid contactor is required for the reduction of the solvent degradation by shortening the contact time. The effects of fine solid particles were investigated with a SGN-Robatel LX-208N contactor, following the uranium extraction and re-extraction performance tests. It was found as the experimental result that the considerable quantity of solids accumulated in the rotor of the centrifugal contactor. As for this experimental apparatus, the flow diagram for the centrifugal rapid contactor and auxiliary apparatuses is shown, which are the same system used for the uranium extraction and re-extraction tests. The schematic diagram, the typical stage construction and fluid transfer path of the LX-208 contactor are illustrated. The main specifications of the LX-208 contactor are as follows: the internal diameter of a rotating bowl 200 mm, the material SUS 316, the number of stages 8, and the total hold-up volume of the contactor 1.8 l. Most tests were carried out with aqueous feed only, because white Alundum is easily deposited in the rotor, and the particle concentration in effluent stream becomes undetectable when organic and aqueous feeds are supplied simultaneously. As the experimental results, the correlation of Alundum concentration in effluent and running time, the effect of rotor speed on effluent stream concentration, the particle size distribution curves for No. 6000 and No. 8000 white Alundum, the effect of flow rate on effluent stream concentration and the effect of flow rate on particle size distribution for both No. 6000 and No. 8000 white Alundum are presented. (Nakai, Y.)

  1. Understanding and modeling retention of mammalian cells in fluidized bed centrifuges.

    Kelly, William; Rubin, Jonathan; Scully, Jennifer; Kamaraju, Hari; Wnukowski, Piotr; Bhatia, Ravinder

    2016-11-01

    Within the last decade, fully disposable centrifuge technologies, fluidized-bed centrifuges (FBC), have been introduced to the biologics industry. The FBC has found a niche in cell therapy where it is used to collect, concentrate, and then wash mammalian cell product while continuously discarding centrate. The goal of this research was to determine optimum FBC conditions for recovery of live cells, and to develop a mathematical model that can assist with process scaleup. Cell losses can occur during bed formation via flow channels within the bed. Experimental results with the kSep400 centrifuge indicate that, for a given volume processed: the bed height (a bed compactness indicator) is affected by RPM and flowrate, and dead cells are selectively removed during operation. To explain these results, two modeling approaches were used: (i) equating the centrifugal and inertial forces on the cells (i.e., a force balance model or FBM) and (ii) a two-phase computational fluid dynamics (CFD) model to predict liquid flow patterns and cell retention in the bowl. Both models predicted bed height vs. time reasonably well, though the CFD model proved more accurate. The flow patterns predicted by CFD indicate a Coriolis-driven flow that enhances uniformity of cells in the bed and may lead to cell losses in the outflow over time. The CFD-predicted loss of viable cells and selective removal of the dead cells generally agreed with experimental trends, but did over-predict dead cell loss by up to 3-fold for some of the conditions. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1520-1530, 2016. © 2016 American Institute of Chemical Engineers.

  2. Rotational spectroscopy with an optical centrifuge.

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

    2014-03-07

    We demonstrate a new spectroscopic method for studying electronic transitions in molecules with extremely broad range of angular momentum. We employ an optical centrifuge to create narrow rotational wave packets in the ground electronic state of (16)O2. Using the technique of resonance-enhanced multi-photon ionization, we record the spectrum of multiple ro-vibrational transitions between X(3)Σg(-) and C(3)Πg electronic manifolds of oxygen. Direct control of rotational excitation, extending to rotational quantum numbers as high as N ≳ 120, enables us to interpret the complex structure of rotational spectra of C(3)Πg beyond thermally accessible levels.

  3. Gas centrifuge bibliography 1980-1982

    Lowe, G.E.; Morrison, M.

    1983-06-01

    A bibliography, with abstract, is presented of the gas centrifuge literature published from 1980 to 1982 inclusive. It supplements PG Information Series 25 (CA), BNFL Information Series 15 (CA) and BNFL Information Series 23 (CA), which covered the periods 1895 to 1970, 1970 to 1974, and 1975 to 1979 respectively. After bibliographies and books and pamphlets, the main list is arranged chronologically under the headings, Reports, Journal articles, and Conference papers. Items omitted from the earlier bibliographies or received too late for inclusion in this, have been listed separately. There are author, report number and subject indexes. (U.K.)

  4. Isotopic enrichment in a plasma centrifuge

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

    1986-05-01

    A rotating fully ionized plasma column was produced in a vacuum-arc centrifuge. The apparatus is described and new results for the rotational velocity and isotope enrichment of carbon and metal plasmas are shown. The ion rotation velocity is derived from electrostatic probes measurents and from the azimuthal displacement of the material deposited behind of a narrow slit. The isotope enrichment is measured with a modified quadrupole mass spectrometer, which determines, in situ, the relative abundance of the isotopes at the end of the plasm column at various radil positions. (Author) [pt

  5. Development of liquid nitrogen Centrifugal Pump

    Abe, M; Sagiyama, R; Tsuchiya, H; Takayama, T; Torii, Y; Nakamura, M; Hoshino, Y; Odashima, Y

    2009-01-01

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

  6. DESIGN PARAMETERS OF CENTRIFUGAL COMPRESSOR INDUCER

    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.

  7. Low-temperature centrifugal helium compressor

    Kawada, M.; Togo, S.; Akiyama, Y.; Wada, R.

    1974-01-01

    A centrifugal helium compressor with gas bearings, which can be operated at the temperature of liquid nitrogen, has been investigated. This compressor has the advantages that the compression ratio should be higher than the room temperature operation and that the contamination of helium could be eliminated. The outer diameter of the rotor is 112 mm. The experimental result for helium gas at low temperature shows a flow rate of 47 g/s and a compression ratio of 1.2 when the inlet pressure was 1 ata and the rotational speed 550 rev/s. The investigation is now focused on obtaining a compression ratio of 1.5. (author)

  8. Computing sextic centrifugal distortion constants by DFT: A benchmark analysis on halogenated compounds

    Pietropolli Charmet, Andrea; Stoppa, Paolo; Tasinato, Nicola; Giorgianni, Santi

    2017-05-01

    This work presents a benchmark study on the calculation of the sextic centrifugal distortion constants employing cubic force fields computed by means of density functional theory (DFT). For a set of semi-rigid halogenated organic compounds several functionals (B2PLYP, B3LYP, B3PW91, M06, M06-2X, O3LYP, X3LYP, ωB97XD, CAM-B3LYP, LC-ωPBE, PBE0, B97-1 and B97-D) were used for computing the sextic centrifugal distortion constants. The effects related to the size of basis sets and the performances of hybrid approaches, where the harmonic data obtained at higher level of electronic correlation are coupled with cubic force constants yielded by DFT functionals, are presented and discussed. The predicted values were compared to both the available data published in the literature and those obtained by calculations carried out at increasing level of electronic correlation: Hartree-Fock Self Consistent Field (HF-SCF), second order Møller-Plesset perturbation theory (MP2), and coupled-cluster single and double (CCSD) level of theory. Different hybrid approaches, having the cubic force field computed at DFT level of theory coupled to harmonic data computed at increasing level of electronic correlation (up to CCSD level of theory augmented by a perturbational estimate of the effects of connected triple excitations, CCSD(T)) were considered. The obtained results demonstrate that they can represent reliable and computationally affordable methods to predict sextic centrifugal terms with an accuracy almost comparable to that yielded by the more expensive anharmonic force fields fully computed at MP2 and CCSD levels of theory. In view of their reduced computational cost, these hybrid approaches pave the route to the study of more complex systems.

  9. 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.

    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

  10. Solidification microstructure of centrifugally cast Inconel 625

    Silvia Barella

    2017-07-01

    Full Text Available Centrifugal casting is a foundry process allowing the production of near net-shaped axially symmetrical components. The present study focuses on the microstructural characterization of centrifugally cast alloys featuring different chemical compositions for the construction of spheres applied in valves made of alloy IN625 for operation at high pressure. Control of the solidification microstructure is needed to assure the reliability of the castings. Actually, a Ni-base superalloy such as this one should have an outstanding combination of mechanical properties, high temperature stability and corrosion resistance. Alloys such as IN625 are characterised by a large amount of alloying elements and a wide solidification range, so they can be affected by micro-porosity defects, related to the shrinkage difference between the matrix and the secondary reinforcing phases (Nb-rich carbides and Laves phase. In this study, the microstructure characterization was performed as a function of the applied heat treatments and it was coupled with a calorimetric analysis in order to understand the mechanism ruling the formation of micro-porosities that can assure alloy soundness. The obtained results show that the presence of micro-porosities is governed by morphology and by the size of the secondary phases, and the presence of the observed secondary phases is detrimental to corrosion resistance.

  11. Centrifugal separator. [for production of enriched U

    Takahashi, J; Fujita, S I

    1970-02-25

    In a centrifugal separator of the concurrent flow through type, a rotating member having an inner and outer cylinder with an air gap therebetween is supported within a frame. A mixture to be separated is supplied to the interior of the inner cylinder through a hollow shaft inserted coaxially within the rotatable portion of a driving apparatus, with one end of the rotatable portion attached to the common inlet end cap of the cylinders which are thereby rotated. There are provided holes at the upper end of the inner cylinder through which the mixture enters the air gap to undergo separation, with the thus separated lighter component entering a separate chamber at the lower end of the inner cylinder through holes provided therein to thereafter be discharged from the outlet end thereof, while the heavier component is discharged from the outlet end of the outer cylinder through holes provided therein. The separated gases then enter their respective chambers within the frame for final removal where they are isolated from each other by sealing means to prevent remixture. Efficiency is heightened and, since no other complicated means are necessary for dividing and removing the separated components, the structure of the present centrifuge can be simplified and reduced in size.

  12. Centrifugally Spun Recycled PET: Processing and Characterization

    Phu Phong Vo

    2018-06-01

    Full Text Available Centrifugal spinning, which is a high-productivity fiber fabrication technique, was used to produce a value-added product from recycled poly(ethylene terephthalate (rPET. In the present study, rPET fibers, with fiber diameters ranging from submicron to micrometer in scale, were fabricated by spinning a solution of rPET in a mixture of dichloromethane and trifluoroacetic acid. The influence of the polymer solution concentration (the viscosity, the rotational speed of the spinneret, and the inner diameter of the needles on the formation and morphology and mechanical properties of the fibers were examined through scanning electron microscopy and using a tensile testing machine. The thermal behaviors of fibrous mats with various average diameters were also investigated through differential scanning calorimetry. The smoothest and smallest fibers, with an average diameter of 619 nm, were generated using an rPET solution of 10 wt % under a rotation speed of 15,000 rpm using needles having an inner diameter of 160 μm. The fibrous mats have an average tensile strength and modulus of 4.3 MPa and 34.4 MPa, respectively. The productivity and the mechanical properties indicate that centrifugal spinning is an effective technique to fabricate high-value product from rPET.

  13. Some aversive characteristics of centrifugally generated gravity.

    Altman, F.

    1973-01-01

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

  14. Centrifugally Stimulated Exospheric Ion Escape at Mercury

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

    2012-01-01

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

  15. Design, Development and Analysis of Centrifugal Blower

    Baloni, Beena Devendra; Channiwala, Salim Abbasbhai; Harsha, Sugnanam Naga Ramannath

    2018-06-01

    Centrifugal blowers are widely used turbomachines equipment in all kinds of modern and domestic life. Manufacturing of blowers seldom follow an optimum design solution for individual blower. Although centrifugal blowers are developed as highly efficient machines, design is still based on various empirical and semi empirical rules proposed by fan designers. There are different methodologies used to design the impeller and other components of blowers. The objective of present study is to study explicit design methodologies and tracing unified design to get better design point performance. This unified design methodology is based more on fundamental concepts and minimum assumptions. Parametric study is also carried out for the effect of design parameters on pressure ratio and their interdependency in the design. The code is developed based on a unified design using C programming. Numerical analysis is carried out to check the flow parameters inside the blower. Two blowers, one based on the present design and other on industrial design, are developed with a standard OEM blower manufacturing unit. A comparison of both designs is done based on experimental performance analysis as per IS standard. The results suggest better efficiency and more flow rate for the same pressure head in case of the present design compared with industrial one.

  16. Wave Augmented Diffusers for Centrifugal Compressors

    Paxson, Daniel E.; Skoch, Gary J.

    1998-01-01

    A conceptual device is introduced which would utilize unsteady wave motion to slow and turn flows in the diffuser section of a centrifugal compressor. The envisioned device would substantially reduce the size of conventional centrifugal diffusers by eliminating the relatively large ninety degree bend needed to turn the flow from the radial/tangential to the axial direction. The bend would be replaced by a wall and the flow would instead exit through a series of rotating ports located on a disk, adjacent to the diffuser hub, and fixed to the impeller shaft. The ports would generate both expansion and compression waves which would rapidly transition from the hub/shroud (axial) direction to the radial/tangential direction. The waves would in turn induce radial/tangential and axial flow. This paper presents a detailed description of the device. Simplified cycle analysis and performance results are presented which were obtained using a time accurate, quasi-one-dimensional CFD code with models for turning, port flow conditions, and losses due to wall shear stress. The results indicate that a periodic wave system can be established which yields diffuser performance comparable to a conventional diffuser. Discussion concerning feasibility, accuracy, and integration follow.

  17. Experimental Investigation of Centrifugal Compressor Stabilization Techniques

    Skoch, Gary J.

    2003-01-01

    Results from a series of experiments to investigate techniques for extending the stable flow range of a centrifugal compressor are reported. The research was conducted in a high-speed centrifugal compressor at the NASA Glenn Research Center. The stabilizing effect of steadily flowing air-streams injected into the vaneless region of a vane-island diffuser through the shroud surface is described. Parametric variations of injection angle, injection flow rate, number of injectors, injector spacing, and injection versus bleed were investigated for a range of impeller speeds and tip clearances. Both the compressor discharge and an external source were used for the injection air supply. The stabilizing effect of flow obstructions created by tubes that were inserted into the diffuser vaneless space through the shroud was also investigated. Tube immersion into the vaneless space was varied in the flow obstruction experiments. Results from testing done at impeller design speed and tip clearance are presented. Surge margin improved by 1.7 points using injection air that was supplied from within the compressor. Externally supplied injection air was used to return the compressor to stable operation after being throttled into surge. The tubes, which were capped to prevent mass flux, provided 9.3 points of additional surge margin over the baseline surge margin of 11.7 points.

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

    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...

  19. Experimental study of xenon isotopes production by gas centrifuge

    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)

  20. Scaling up debris-flow experiments on a centrifuge

    Hung, C.; Capart, H.; Crone, T. J.; Grinspum, E.; Hsu, L.; Kaufman, D.; Li, L.; Ling, H.; Reitz, M. D.; Smith, B.; Stark, C. P.

    2013-12-01

    Boundary forces generated by debris flows can be powerful enough to erode bedrock and cause considerable damage to infrastructure during runout. Formulation of an erosion-rate law for debris flows is therefore a high priority, and it makes sense to build such a law around laboratory experiments. However, running experiments big enough to generate realistic boundary forces is a logistical challenge to say the least [1]. One alternative is to run table-top simulations with unnaturally weak but fast-eroding pseudo-bedrock, another is to extrapolate from micro-erosion of natural substrates driven by unnaturally weak impacts; hybrid-scale experiments have also been conducted [2]. Here we take a different approach in which we scale up granular impact forces by running our experiments under enhanced gravity in a geotechnical centrifuge [3]. Using a 40cm-diameter rotating drum [2] spun at up to 100g, we generate debris flows with an effective depth of over several meters. By varying effective gravity from 1g to 100g we explore the scaling of granular flow forces and the consequent bed and wall erosion rates. The velocity and density structure of these granular flows is monitored using laser sheets, high-speed video, and particle tracking [4], and the progressive erosion of the boundary surfaces is measured by laser scanning. The force structures and their fluctuations within the granular mass and at the boundaries are explored with contact dynamics numerical simulations that mimic the lab experimental conditions [5]. In this presentation we summarize these results and discuss how they can contribute to the formulation of debris-flow erosion law. [1] Major, J. J. (1997), Journal of Geology 105: 345-366, doi:10.1086/515930 [2] Hsu, L. (2010), Ph.D. thesis, University of California, Berkeley [3] Brucks, A., et al (2007), Physical Review E 75, 032301, doi:10.1103/PhysRevE.75.032301 [4] Spinewine, B., et al (2011), Experiments in Fluids 50: 1507-1525, doi: 10.1007/s00348

  1. Modeling centrifugal cell washers using computational fluid dynamics.

    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.

  2. Effect of science laboratory centrifuge of space station environment

    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.

  3. Development of uranium enrichment technology by gas centrifugation

    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)

  4. A cubesat centrifuge for long duration milligravity research.

    Asphaug, Erik; Thangavelautham, Jekan; Klesh, Andrew; Chandra, Aman; Nallapu, Ravi; Raura, Laksh; Herreras-Martinez, Mercedes; Schwartz, Stephen

    2017-01-01

    We advocate a low-cost strategy for long-duration research into the 'milligravity' environment of asteroids, comets and small moons, where surface gravity is a vector field typically less than 1/1000 the gravity of Earth. Unlike the microgravity environment of space, there is a directionality that gives rise, over time, to strangely familiar geologic textures and landforms. In addition to advancing planetary science, and furthering technologies for hazardous asteroid mitigation and in situ resource utilization, simplified access to long-duration milligravity offers significant potential for advancing human spaceflight, biomedicine and manufacturing. We show that a commodity 3U (10 × 10 × 34 cm 3 ) cubesat containing a laboratory of loose materials can be spun to 1 r.p.m. = 2 π /60 s -1 on its long axis, creating a centrifugal force equivalent to the surface gravity of a kilometer-sized asteroid. We describe the first flight demonstration, where small meteorite fragments will pile up to create a patch of real regolith under realistic asteroid conditions, paving the way for subsequent missions where landing and mobility technology can be flight-proven in the operational environment, in low-Earth orbit. The 3U design can be adapted for use onboard the International Space Station to allow for variable gravity experiments under ambient temperature and pressure for a broader range of experiments.

  5. Compressible Convection Experiment using Xenon Gas in a Centrifuge

    Menaut, R.; Alboussiere, T.; Corre, Y.; Huguet, L.; Labrosse, S.; Deguen, R.; Moulin, M.

    2017-12-01

    We present here an experiment especially designed to study compressible convection in the lab. For significant compressible convection effects, the parameters of the experiment have to be optimized: we use xenon gaz in a cubic cell. This cell is placed in a centrifuge to artificially increase the apparent gravity and heated from below. With these choices, we are able to reach a dissipation number close to Earth's outer core value. We will present our results for different heating fluxes and rotation rates. We success to observe an adiabatic gradient of 3K/cm in the cell. Studies of pressure and temperature fluctuations lead us to think that the convection takes place under the form of a single roll in the cell for high heating flux. Moreover, these fluctuations show that the flow is geostrophic due to the high rotation speed. This important role of rotation, via Coriolis force effects, in our experimental setup leads us to develop a 2D quasigeostrophic compressible model in the anelastic liquid approximation. We test numerically this model with the finite element solver FreeFem++ and compare its results with our experimental data. In conclusion, we will present our project for the next experiment in which the cubic cell will be replace by a annulus cell. We will discuss the new expected effects due to this geometry as Rossby waves and zonal flows.

  6. Gyro-effect stabilizes unstable permanent maglev centrifugal pump.

    Qian, Kun-Xi

    2007-03-01

    According to Earnshaw's Theorem (1839), the passive maglev cannot achieve stable equilibrium and thus an extra coil is needed to make the rotor electrically levitated in a heart pump. The author had developed a permanent maglev centrifugal pump utilizing only passive magnetic bearings, to keep the advantages but to avoid the disadvantages of the electric maglev pumps. The equilibrium stability was achieved by use of so-called "gyro-effect": a rotating body with certain high speed can maintain its rotation stably. This pump consisted of a rotor (driven magnets and an impeller), and a stator with motor coil and pump housing. Two passive magnetic bearings between rotor and stator were devised to counteract the attractive force between the motor coil iron core and the rotor driven magnets. Bench testing with saline demonstrated a levitated rotor under preconditions of higher than 3,250 rpm rotation and more than 1 l/min pumping flow. Rotor levitation was demonstrated by 4 Hall sensors on the stator, with evidence of reduced maximal eccentric distance from 0.15 mm to 0.07 mm. The maximal rotor vibration amplitude was 0.06 mm in a gap of 0.15 mm between rotor and stator. It concluded that Gyro-effect can help passive maglev bearings to achieve stabilization of permanent maglev pump; and that high flow rate indicates good hydraulic property of the pump, which helps also the stability of passive maglev pump.

  7. Measuring the ability of military aircrews to adapt to perceived stressors when undergoing centrifuge training.

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

    2014-01-01

    This study assessed the ability of military aircrews to adapt to stressors when undergoing centrifuge training and determined what equipment items caused perceived stress and needed to be upgraded. We used questionnaires and the Rasch model to measure aircrew personnel's ability to adapt to centrifuge training. The measurement items were ranked by 611 military aircrew personnel. Analytical results indicated that the majority of the stress perceived by aircrew personnel resulted from the lightproof cockpit without outer reference. This study prioritized the equipment requiring updating as the lightproof cockpit design, the dim lighting of the cockpit, and the pedal design. A significant difference was found between pilot and non-pilot subjects' stress from the pedal design; and considerable association was discernible between the seat angle design and flight hours accrued. The study results provide aviators, astronauts, and air forces with reliable information as to which equipment items need to be urgently upgraded as their present physiological and psychological effects can affect the effectiveness of centrifuge training.

  8. The characteristics and mechanisms of Au nanoparticles processed by functional centrifugal procedures

    Shiau, Bo-Wen; Lin, Chien-Hung; Liao, Ying-Yen; Lee, Ya-Rong; Liu, Shih-Hao; Ding, Wei-Cheng; Lee, Jia-Ren

    2018-05-01

    In this work, the optical properties of Au nanoparticles processed by centrifugation techniques are studied. Most of the literature related to the control of nanoparticle size has focused on different preparation parameters; however, the wide size distribution is commonly an issue for follow-up investigations and further applications. Therefore, we developed a method in which specific-diameter particles can be effectively separated using different centrifugal procedures. The initial nanoparticle solution with a primary absorption peak at 534 nm is separated into discernible resonance wavelengths from 526 to 537 nm, with corresponding particle sizes from 30 to 55 nm. For the atomic force microscopy analysis of nanoparticle size, a dry cetyltrimethylammonium bromide (CTAB) film often covers the particles and interferes with the measurement; thus, CTAB has to be removed. However, if too much CTAB is removed, the surface of the Au nanoparticle becomes unstable, and the particles aggregate. Accordingly, we used UV spectroscopy to monitor the CTAB content; properly adjust the rotational speed and the number of centrifugation stages; and design a method that can effectively remove impurities, avoid clustering, and enable particle size measurement. The usually complicated procedures and high cost of preparation of specific-size Au nanoparticles are greatly simplified and reduced by the convenient extraction process proposed in this work, which would benefit related research and applications.

  9. Microfluidic Adaptation of Density-Gradient Centrifugation for Isolation of Particles and Cells

    Yuxi Sun

    2017-08-01

    Full Text Available Density-gradient centrifugation is a label-free approach that has been extensively used for cell separations. Though elegant, this process is time-consuming (>30 min, subjects cells to high levels of stress (>350 g and relies on user skill to enable fractionation of cells that layer as a narrow band between the density-gradient medium and platelet-rich plasma. We hypothesized that microfluidic adaptation of this technique could transform this process into a rapid fractionation approach where samples are separated in a continuous fashion while being exposed to lower levels of stress (<100 g for shorter durations of time (<3 min. To demonstrate proof-of-concept, we designed a microfluidic density-gradient centrifugation device and constructed a setup to introduce samples and medium like Ficoll in a continuous, pump-less fashion where cells and particles can be exposed to centrifugal force and separated via different outlets. Proof-of-concept studies using binary mixtures of low-density polystyrene beads (1.02 g/cm3 and high-density silicon dioxide beads (2.2 g/cm3 with Ficoll–Paque (1.06 g/cm3 show that separation is indeed feasible with >99% separation efficiency suggesting that this approach can be further adapted for separation of cells.

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

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

    1997-01-01

    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

  11. ANALYTICAL SOLUTION FOR WAVES IN PLANETS WITH ATMOSPHERIC SUPERROTATION. II. LAMB, SURFACE, AND CENTRIFUGAL WAVES

    Peralta, J.; López-Valverde, M. A.; Imamura, T.; Read, P. L.; Luz, D.; Piccialli, A.

    2014-01-01

    This paper is the second in a two-part study devoted to developing tools for a systematic classification of the wide variety of atmospheric waves expected on slowly rotating planets with atmospheric superrotation. Starting with the primitive equations for a cyclostrophic regime, we have deduced the analytical solution for the possible waves, simultaneously including the effect of the metric terms for the centrifugal force and the meridional shear of the background wind. In those cases where the conditions for the method of the multiple scales in height are met, these wave solutions are also valid when vertical shear of the background wind is present. A total of six types of waves have been found and their properties were characterized in terms of the corresponding dispersion relations and wave structures. In this second part, we study the waves' solutions when several atmospheric approximations are applied: Lamb, surface, and centrifugal waves. Lamb and surface waves are found to be quite similar to those in a geostrophic regime. By contrast, centrifugal waves turn out to be a special case of Rossby waves that arise in atmospheres in cyclostrophic balance. Finally, we use our results to identify the nature of the waves behind atmospheric periodicities found in polar and lower latitudes of Venus's atmosphere

  12. Axisymmetric drop shape analysis for estimating the surface tension of cell aggregates by centrifugation.

    Kalantarian, Ali; Ninomiya, Hiromasa; Saad, Sameh M I; David, Robert; Winklbauer, Rudolf; Neumann, A Wilhelm

    2009-02-18

    Biological tissues behave in certain respects like liquids. Consequently, the surface tension concept can be used to explain aspects of the in vitro and in vivo behavior of multicellular aggregates. Unfortunately, conventional methods of surface tension measurement cannot be readily applied to small cell aggregates. This difficulty can be overcome by an experimentally straightforward method consisting of centrifugation followed by axisymmetric drop shape analysis (ADSA). Since the aggregates typically show roughness, standard ADSA cannot be applied and we introduce a novel numerical method called ADSA-IP (ADSA for imperfect profile) for this purpose. To examine the new methodology, embryonic tissues from the gastrula of the frog, Xenopus laevis, deformed in the centrifuge are used. It is confirmed that surface tension measurements are independent of centrifugal force and aggregate size. Surface tension is measured for ectodermal cells in four sample batches, and varies between 1.1 and 7.7 mJ/m2. Surface tension is also measured for aggregates of cells expressing cytoplasmically truncated EP/C-cadherin, and is approximately half as large. In parallel, such aggregates show a reduction in convergent extension-driven elongation after activin treatment, reflecting diminished intercellular cohesion.

  13. Joining of Ni-TiC FGM and Ni-Al Intermetallics by Centrifugal Combustion Synthesis

    Ohmi, Tatsuya; Matsuura, Kiyotaka; Iguchi, Manabu; Mizuma, Kiminori

    2008-01-01

    A centrifugal combustion synthesis (CCS) process has been investigated to join a Ni-Al intermetallic compound and a Ni-TiC cermet. The cermet, a tubular graphite mold, and a green compact of reactants consisting of Al, Ni and NiO were set in a centrifugal caster. When the combustion synthesis reaction was induced in the centrifugal force field, a synthesized molten Ni-Al alloy flowed into the graphite mold and joined to the cermet. The soundness of the joint interface depended on the volume percentage of TiC phase in the cermet. A lot of defects were formed near the interface between the Ni-TiC cermet and the cast Ni-Al alloy when the volume percentage of TiC was 50% or higher. For this kind of cermet system, using a functionally graded cermet such as Ni-10 vol.%TiC/Ni-25 vol.%TiC/Ni-50 vol.%TiC overcame this difficulty. The four-point bending strength of the joined specimen consisting of the three-layered FGM cermet and cast Ni-29 mol%Al alloy was 1010 MPa which is close to the result for a Ni-29 mol%Al alloy specimen

  14. ANALYTICAL SOLUTION FOR WAVES IN PLANETS WITH ATMOSPHERIC SUPERROTATION. II. LAMB, SURFACE, AND CENTRIFUGAL WAVES

    Peralta, J.; López-Valverde, M. A. [Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía, 18008 Granada (Spain); Imamura, T. [Institute of Space and Astronautical Science-Japan Aerospace Exploration Agency 3-1-1, Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Read, P. L. [Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford (United Kingdom); Luz, D. [Centro de Astronomia e Astrofísica da Universidade de Lisboa (CAAUL), Observatório Astronómico de Lisboa, Tapada da Ajuda, 1349-018 Lisboa (Portugal); Piccialli, A., E-mail: peralta@iaa.es [LATMOS, UVSQ, 11 bd dAlembert, 78280 Guyancourt (France)

    2014-07-01

    This paper is the second in a two-part study devoted to developing tools for a systematic classification of the wide variety of atmospheric waves expected on slowly rotating planets with atmospheric superrotation. Starting with the primitive equations for a cyclostrophic regime, we have deduced the analytical solution for the possible waves, simultaneously including the effect of the metric terms for the centrifugal force and the meridional shear of the background wind. In those cases where the conditions for the method of the multiple scales in height are met, these wave solutions are also valid when vertical shear of the background wind is present. A total of six types of waves have been found and their properties were characterized in terms of the corresponding dispersion relations and wave structures. In this second part, we study the waves' solutions when several atmospheric approximations are applied: Lamb, surface, and centrifugal waves. Lamb and surface waves are found to be quite similar to those in a geostrophic regime. By contrast, centrifugal waves turn out to be a special case of Rossby waves that arise in atmospheres in cyclostrophic balance. Finally, we use our results to identify the nature of the waves behind atmospheric periodicities found in polar and lower latitudes of Venus's atmosphere.

  15. Multistage centrifugal extractor of E92 model

    Wang Houheng; Xing Zhifu; Liu Xiangyan; Liu Shi; Wan Yi; Liang Kui; Hu Benyue

    1987-01-01

    The E92 Model multistage centrifugal extractor has been developed for the recovery of uranium and plutonium from spent nuclear reactor fuel. It offers the following advantages: shorter residence time, low hlod-up, less space required, and simplified startup and shutdown procedures, etc. Experiments on performaces of hydraulics, mass-transfer and crud discharging have proved that this unit provides a wide range of operation. The total flow rate can very from 300 to 450 L/h at organic to aqueous flow ratio of 1 to 5. The unit is designed for ratio of oranic to aqueous phase densities at a range of 0.75 to 0.85. Overall extraction and back-extraction efficiencies which is great than 99.99% were achieved using natural uranium as feed. Experiments showed that mechanical assembling and disassembling of the unit could be rapidly carried out. A run continuning up to 500 hours was stable

  16. Closed continuous-flow centrifuge rotor

    Breillatt, Jr., Julian P.; Remenyik, Carl J.; Sartory, Walter K.; Thacker, Louis H.; Penland, William Z.

    1976-01-01

    A blood separation centrifuge rotor having a generally parabolic core disposed concentrically and spaced apart within a housing having a similarly shaped cavity. Blood is introduced through a central inlet and into a central passageway enlarged downwardly to decrease the velocity of the entrant blood. Septa are disposed inside the central passageway to induce rotation of the entrant blood. A separation chamber is defined between the core and the housing wherein the whole blood is separated into red cell, white cell, and plasma zones. The zones are separated by annular splitter blades disposed within the separation chamber. The separated components are continuously removed through conduits communicating through a face seal to the outside of the rotor.

  17. Recent advances in centrifugal contactors design

    Leonard, R.A.

    1987-10-01

    Advances in thedesign of the Argonne centrifugal contactor for solvent extaction are being realized as these contactors are built, tested, and used to implement the TRUEX process for the cleanup of nuclear waste liquids. These advances include (1) using off-the-shelf, face-mounted motors, (2) modifying the contractor so that relatively volatile solvents can be used, (3) adding a high-level liquid detector that can be used to alert the plant operator of process upsets, (4) providing secondary feed ports, (5) optimizing support frame design, (6) maintaining a linear design with external interstage lines so the stages can be allocated as needed for extraction, scrub, strip, and solvent cleanup operations, and (7) developing features that facilitate contractor operation in remote facilities. 11 refs., 8 figs

  18. Potential commercial applications of centrifuge technology

    1985-08-01

    As part of an effort to prevent the loss of and maximize the use of unique developments of the centrifuge program, this document identifies and briefly describes unclassified technologies potentially available for transfer. In addition, this document presents a preliminary plan for action needed to carry out the transfer activity. Continuing efforts will provide additional descriptions of technologies which have applications that are not as apparent or as obvious as those presented here. Declassification of some of the program information, now classified as restricted data, would permit the descriptions of additional technologies which have significant commercial potential. The following are major areas of technology where transfer opportunities exist: biomedical; separation; motors and control systems; materials; vacuum; dynamics and balancing; and diagnostics and instrumentation

  19. Algorithm for Controlling a Centrifugal Compressor

    Benedict, Scott M.

    2004-01-01

    An algorithm has been developed for controlling a centrifugal compressor that serves as the prime mover in a heatpump system. Experimental studies have shown that the operating conditions for maximum compressor efficiency are close to the boundary beyond which surge occurs. Compressor surge is a destructive condition in which there are instantaneous reversals of flow associated with a high outlet-to-inlet pressure differential. For a given cooling load, the algorithm sets the compressor speed at the lowest possible value while adjusting the inlet guide vane angle and diffuser vane angle to maximize efficiency, subject to an overriding requirement to prevent surge. The onset of surge is detected via the onset of oscillations of the electric current supplied to the compressor motor, associated with surge-induced oscillations of the torque exerted by and on the compressor rotor. The algorithm can be implemented in any of several computer languages.

  20. Flight experience and the perception of pitch angular displacements in a gondola centrifuge.

    Tribukait, Arne; Eiken, Ola

    2012-05-01

    It has been shown that flight experience may induce an adaptation of the vestibular system. The aim of the present work was to elucidate whether pilots, in comparison with non-pilots, have an increased responsiveness to angular displacement canal stimuli in the pitch plane during a conflict between the otolith organs and the semicircular canals. In a large swing-out gondola centrifuge, eight non-pilots, eight fighter pilots, and eight helicopter pilots underwent three runs (2 G, 5 min) heading forward, centripetally, and centrifugally. The direction of the gravitoinertial force was constant with respect to the subject. The visually perceived eye level (VPEL) was measured in darkness by means of an adjustable luminous dot. In the forward position the three groups produced similar results. After acceleration there was a sensation of backward tilt and an increasing depression of VPEL. This effect was smaller in the centripetal position and larger in the centrifugal position. The difference in VPEL between the opposite positions constitutes a measure of the ability to sense the pitch angular displacement canal stimulus related to the swing out of the gondola (60 degrees). This difference was most pronounced initially at the 2-G plateau (mean +/- SD): 13.5 +/- 12.9 degrees (non-pilots), 41.6 +/- 21.1 degrees (fighter pilots), and 19.5 +/- 14.0 degrees (helicopter pilots). There was no significant difference between non-pilots and helicopter pilots. Fighter pilots differed significantly from both non-pilots and helicopter pilots. Vestibular learning effects of flying may be revealed in a centrifuge. Fighter pilots had an increased ability, as compared to non-pilots and helicopter pilots, to perceive pitch angular displacements.

  1. Acute hydrodynamic damage induced by SPLITT fractionation and centrifugation in red blood cells.

    Urbina, Adriana; Godoy-Silva, Ruben; Hoyos, Mauricio; Camacho, Marcela

    2016-05-01

    Though blood bank processing traditionally employs centrifugation, new separation techniques may be appealing for large scale processes. Split-flow fractionation (SPLITT) is a family of techniques that separates in absence of labelling and uses very low flow rates and force fields, and is therefore expected to minimize cell damage. However, the hydrodynamic stress and possible consequent damaging effects of SPLITT fractionation have not been yet examined. The aim of this study was to investigate the hydrodynamic damage of SPLITT fractionation to human red blood cells, and to compare these effects with those induced by centrifugation. Peripheral whole blood samples were collected from healthy volunteers. Samples were diluted in a buffered saline solution, and were exposed to SPLITT fractionation (flow rates 1-10 ml/min) or centrifugation (100-1500 g) for 10 min. Cell viability, shape, diameter, mean corpuscular hemoglobin, and membrane potential were measured. Under the operating conditions employed, both SPLITT and centrifugation maintained cell viability above 98%, but resulted in significant sublethal damage, including echinocyte formation, decreased cell diameter, decreased mean corpuscular hemoglobin, and membrane hyperpolarization which was inhibited by EGTA. Wall shear stress and maximum energy dissipation rate showed significant correlation with lethal and sublethal damage. Our data do not support the assumption that SPLITT fractionation induces very low shear stress and is innocuous to cell function. Some changes in SPLITT channel design are suggested to minimize cell damage. Measurement of membrane potential and cell diameter could provide a new, reliable and convenient basis for evaluation of hydrodynamic effects on different cell models, allowing identification of optimal operating conditions on different scales. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Advances in primary recovery: centrifugation and membrane technology.

    Roush, David J; Lu, Yuefeng

    2008-01-01

    Significant and continual improvements in upstream processing for biologics have resulted in challenges for downstream processing, both primary recovery and purification. Given the high cell densities achievable in both microbial and mammalian cell culture processes, primary recovery can be a significant bottleneck in both clinical and commercial manufacturing. The combination of increased product titer and low viability leads to significant relative increases in the levels of process impurities such as lipids, intracellular proteins and nucleic acid versus the product. In addition, cell culture media components such as soy and yeast hydrolysates have been widely applied to achieve the cell culture densities needed for higher titers. Many of the process impurities can be negatively charged at harvest pH and can form colloids during the cell culture and harvest processes. The wide size distribution of these particles and the potential for additional particles to be generated by shear forces within a centrifuge may result in insufficient clarification to prevent fouling of subsequent filters. The other residual process impurities can lead to precipitation and increased turbidity during processing and even interference with the performance of the capturing chromatographic step. Primary recovery also poses significant challenges owing to the necessity to execute in an expedient manner to minimize both product degradation and bioburden concerns. Both microfiltration and centrifugation coupled with depth filtration have been employed successfully as primary recovery processing steps. Advances in the design and application of membrane technology for microfiltration and dead-end filtration have contributed to significant improvements in process performance and integration, in some cases allowing for a combination of multiple unit operations in a given step. Although these advances have increased productivity and reliability, the net result is that optimization of primary

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

    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.

  4. Installation process of suction anchors in Gulf of Guinea clay : Centrifuge modelling

    THOREL, Luc; GARNIER, Jacques; RAULT, Gérard; DENDANI, Hédi; COLLIAT, JL

    2010-01-01

    The preparation process of a deepwater Gulf of Guinea clay for modelling of 24 m long suction anchors at a scale of 1/100 in the LCPC centrifuge, the clay characteristics and the installation phase (self-weight and suction) are presented. Two types of caissons have been tested in each tub : one with stiffeners and the other without stiffener. The embedment ratio is close to the suction caisson's slenderness of 3. An analysis of the forces of suction and soil friction shows, as expected, hi...

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

    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)

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

    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.

  7. Separation of Nanoparticles in Aqueous Multiphase Systems through Centrifugation

    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.

  8. Fluid dynamic interaction between water hammer and centrifugal pumps

    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.

  9. Modern gas centrifuge and rarefied-gas dynamics

    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

  10. Numerical simulation of the unsteady progress in centrifuge

    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. Separation of Nanoparticles in Aqueous Multiphase Systems through Centrifugation

    Akbulut, Ozge

    2012-08-08

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

  12. Rotating stall simulation for axial and centrifugal compressors

    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.

  13. Application of CFD in Bioprocessing: Separation of mammalian cells using disc stack centrifuge during production of biotherapeutics.

    Shekhawat, Lalita Kanwar; Sarkar, Jayati; Gupta, Rachit; Hadpe, Sandeep; Rathore, Anurag S

    2018-02-10

    Centrifugation continues to be one of the most commonly used unit operations for achieving efficient harvest of the product from the mammalian cell culture broth during production of therapeutic monoclonal antibodies (mAbs). Since the mammalian cells are known to be shear sensitive, optimal performance of the centrifuge requires a balance between productivity and shear. In this study, Computational Fluid Dynamics (CFD) has been successfully used as a tool to facilitate efficient optimization. Multiphase Eulerian-Eulerian model coupled with Gidaspow drag model along with Eulerian-Eulerian k-ε mixture turbulence model have been used to quantify the complex hydrodynamics of the centrifuge and thus evaluate the turbulent stresses generated by the centrifugal forces. An empirical model has been developed by statistical analysis of experimentally observed cell lysis data as a function of turbulent stresses. An operating window that offers the optimal balance between high productivity, high separation efficiency, and low cell damage has been identified by use of CFD modeling. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Clean-in-Place and Reliability Testing of a Commercial 12.5-cm Annular Centrifugal Contactor at the INL

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

    2007-01-01

    The renewed interest in advancing nuclear energy has spawned the research of advanced technologies for recycling nuclear fuel. A significant portion of the advanced fuel cycle includes the recovery of selected actinides by solvent extraction methods utilizing centrifugal contactors. Although the use of centrifugal contactors for solvent extraction is widely known, their operation is not without challenges. Solutions generated from spent fuel dissolution contain unknown quantities of undissolved solids. A majority of these solids will be removed via various methods of filtration. However, smaller particles are expected to carry through to downstream solvent extraction processes and equipment. In addition, solids/precipitates brought about by mechanical or chemical upsets are another potential area of concern. During processing, particulate captured in the rotor assembly by high centrifugal forces eventually forms a cake-like structure on the inner wall introducing balance problems and negatively affecting phase separations. One of the features recently developed for larger engineering scale Annular Centrifugal Contactors (ACCs) is the Clean-In-Place (CIP) capability. Engineered spray nozzles were installed into the hollow central rotor shaft in all four quadrants of the rotor assembly. This arrangement allows for a very convenient and effective method of solids removal from within the rotor assembly

  15. Clean-in-Place and Reliability Testing of a Commercial 12.5 cm Annular Centrifugal Contactor at the INL

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

    2007-01-01

    The renewed interest in advancing nuclear energy has spawned the research of advanced technologies for recycling nuclear fuel. A significant portion of the advanced fuel cycle includes the recovery of selected actinides by solvent extraction methods utilizing centrifugal contactors. Although the use of centrifugal contactors for solvent extraction is widely known, their operation is not without challenges. Solutions generated from spent fuel dissolution contain unknown quantities of undissolved solids. A majority of these solids will be removed via various methods of filtration. However, smaller particles are expected to carry through to downstream solvent extraction processes and equipment. In addition, solids/precipitates brought about by mechanical or chemical upsets are another potential area of concern. During processing, particulate captured in the rotor assembly by high centrifugal forces eventually forms a cake-like structure on the inner wall introducing balance problems and negatively affecting phase separations. One of the features recently developed for larger engineering scale Annular Centrifugal Contactors (ACCs) is the Clean-In-Place (CIP) capability. Engineered spray nozzles were installed into the hollow central rotor shaft in all four quadrants of the rotor assembly. This arrangement allows for a very convenient and effective method of solids removal from within the rotor assembly

  16. Centrifugal Spinning and Its Energy Storage Applications

    Yao, Lu

    -/micro-fiber production method to substitute electrospinning in industrial production. Recently, centrifugal spinning has gained researchers' attention. The centrifugal spinning method avoids the use of high voltage supply and can work with concentrated solutions, and most importantly, it can increase the production rate of nano-/micro-fibers to at least two orders or magnitude higher than that of electrospinning. This novel fiber fabrication approach is mostly used in tissue engineering field, and it can be potentially applied in preparing electrodes for SIBs and EDLCs. In the present work, we firstly study the influence of solution intrinsic properties and operational parameters using polyacrylonitrile as an example, and establish the processing-structure relationships for this spinning technique. We then use this novel spinning method to prepare porous carbon nanofibers (PCNFs), SnO2 microfibers and lithium-substituted sodium layered transition metal oxide fibers and use them as electrodes for EDLCs and SIBs. The as-prepared PCNFs, SnO2 microfibers and lithiumsubstituted sodium layered transition metal oxide fibers exhibit good electrochemical performance. It is therefore demonstrated that centrifugal spinning can be a promising nano- /micro-fiber preparation approach for mass production of electrode materials used in energy storage applications.

  17. Anomalous Centrifugal Distortion in NH_2

    Martin-Drumel, Marie-Aline; Pirali, Olivier; Coudert, L. H.

    2017-06-01

    The NH2 radical spectrum, first observed by Herzberg and Ramsay, is dominated by a strong Renner-Teller effect giving rise to two electronic states: the bent X ^{2}B_1 ground state and the quasi-linear A ^{2}A_1 excited state. The NH2 radical has been the subject of numerous high-resolution investigations and its electronic and ro-vibrational transitions have been measured. Using synchrotron radiation, new rotational transitions have been recently recorded and a value of the rotational quantum number N as large as 26 could be reached. In the X ^{2}B_1 ground state, the NH2 radical behaves like a triatomic molecule displaying spin-rotation splittings. Due to the lightness of the molecule, a strong coupling between the overall rotation and the bending mode arises whose effects increase with N and lead to the anomalous centrifugal distortion evidenced in the new measurements.^d In this talk the Bending-Rotation approach developed to account for the anomalous centrifugal distortion of the water molecule is modified to include spin-rotation coupling and applied to the fitting of high-resolution data pertaining to the ground electronic state of NH2. A preliminary line position analysis of the available data^{c,d} allowed us to account for 1681 transitions with a unitless standard deviation of 1.2. New transitions could also be assigned in the spectrum recorded by Martin-Drumel et al.^d In the talk, the results obtained with the new theoretical approach will be compared to those retrieved with a Watson-type Hamiltonian and the effects of the vibronic coupling between the ground X ^{2}B_1 and the excited A ^{2}A_1 electronic state will be discussed. Herzberg and Ramsay, J. Chem. Phys. 20 (1952) 347 Dressler and Ramsay, Phil. Trans. R. Soc. A 25 (1959) 553 Hadj Bachir, Huet, Destombes, and Vervloet, J. Molec. Spectrosc. 193 (1999) 326 McKellar, Vervloet, Burkholder, and Howard, J. Molec. Spectrosc. 142 (1990) 319 Morino and Kawaguchi, J. Molec. Spectrosc. 182 (1997) 428

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

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

    2015-01-01

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

  19. Surface-Enhanced Raman Spectroscopy Integrated Centrifugal Microfluidics Platform

    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...

  20. Detection of outliers in gas centrifuge experimental data

    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)

  1. Centrifuge Modelling of Two Civil-Environmental Problems

    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...

  2. Initial Earthquake Centrifuge Model Experiments for the Study of Liquefaction

    Steedman, R

    1998-01-01

    .... These are intended to gather data suitable for the development of improved design approaches for the prediction of liquefaction under earthquake loading using the new centrifuge facility at the WES...

  3. Experimental study on enriching 12C by centrifuge method

    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

  4. Effect of sludge behavior on performance of centrifugal contactor

    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.

  5. Zero-ODP Refrigerants for Low Tonnage Centrifugal Chiller Systems

    Gui, Fulin

    1996-01-01

    ..., HFC-236cb, HFC-236fa, HFC-245cb, and HFC-254cb, for centrifugal chiller applications. We took into account the thermodynamic properties of the refrigerant and aerodynamic properties of the impeller compression process to this evaluation...

  6. Centrifuge Facility for the International Space Station Alpha

    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

  7. Centrifugally Driven Rayleigh-Taylor Instability

    Scase, Matthew; Hill, Richard

    2017-11-01

    The instability that develops at the interface between two fluids of differing density due to the rapid rotation of the system may be considered as a limit of high-rotation rate Rayleigh-Taylor instability. Previously the authors have considered the effect of rotation on a gravitationally dominated Rayleigh-Taylor instability and have shown that some growth modes of instability may be suppressed completely by the stabilizing effect of rotation (Phys. Rev. Fluids 2:024801, Sci. Rep. 5:11706). Here we consider the case of very high rotation rates and a negligible gravitational field. The initial condition is of a dense inner cylinder of fluid surrounded by a lighter layer of fluid. As the system is rotated about the generating axis of the cylinder, the dense inner fluid moves away from the axis and the familiar bubbles and spikes of Rayleigh-Taylor instability develop at the interface. The system may be thought of as a ``fluid-fluid centrifuge''. By developing a model based on an Orr-Sommerfeld equation, we consider the effects of viscosity, surface tension and interface diffusion on the growth rate and modes of instability. We show that under particular circumstances some modes may be stabilized. School of Mathematical Sciences.

  8. High efficiency, variable geometry, centrifugal cryogenic pump

    Forsha, M.D.; Nichols, K.E.; Beale, C.A.

    1994-01-01

    A centrifugal cryogenic pump has been developed which has a basic design that is rugged and reliable with variable speed and variable geometry features that achieve high pump efficiency over a wide range of head-flow conditions. The pump uses a sealless design and rolling element bearings to achieve high reliability and the ruggedness to withstand liquid-vapor slugging. The pump can meet a wide range of variable head, off-design flow requirements and maintain design point efficiency by adjusting the pump speed. The pump also has features that allow the impeller and diffuser blade heights to be adjusted. The adjustable height blades were intended to enhance the pump efficiency when it is operating at constant head, off-design flow rates. For small pumps, the adjustable height blades are not recommended. For larger pumps, they could provide off-design efficiency improvements. This pump was developed for supercritical helium service, but the design is well suited to any cryogenic application where high efficiency is required over a wide range of head-flow conditions

  9. Central centrifugal cicatricial alopecia: challenges and solutions

    Herskovitz I

    2016-08-01

    Full Text Available Ingrid Herskovitz, Mariya Miteva Department of Dermatology and Cutaneous Surgery, University of Miami L Miller School of Medicine, Miami, FL, USA Abstract: Central centrifugal cicatricial alopecia (CCCA is the most common scarring alopecia among African American women. Data about epidemiology, etiology, genetic inheritance, and management are scarce and come from individual reports or small series. CCCA has been associated with hot combing and traumatic hair styling for years; however, studies fail to confirm it as the sole etiologic factor. It has been shown in a small series that CCCA can be inherited in an autosomal dominant fashion, with a partial penetrance and a strong modifying effect of hairstyling and sex. CCCA presents clinically as a central area of progressive irreversible hair loss that expands to the periphery. A patchy form has also been described. Dermoscopy is helpful to identify the optimal site for the biopsy, which establishes the diagnosis. Well-designed randomized controlled trials are needed to discover the optimal management. At this point, patients are advised to avoid traction and chemical treatments; topical and intralesional steroids, calcineurin inhibitors, and minoxidil can be helpful in halting the progression. Keywords: hair loss, alopecia, dermatoscopy, dermoscopy, trichoscopy, black scalp, African American, scarring alopecia

  10. Wave Augmented Diffuser for Centrifugal Compressor

    Skoch, Gary J. (Inventor); Paxson, Daniel E. (Inventor)

    2001-01-01

    A wave augmented diffuser for a centrifugal compressor surrounds the outlet of an impeller that rotates on a drive shaft having an axis of rotation. The impeller brings flow in in an axial direction and imparts kinetic energy to the flow discharging it in radial and tangential directions. The flow is discharged into a plurality of circumferentially disposed wave chambers. The wave chambers are periodically opened and closed by a rotary valve such that the flow through the diffuser is unsteady. The valve includes a plurality of valve openings that are periodically brought into and out of fluid communication with the wave chambers. When the wave chambers are closed, a reflected compression wave moves upstream towards the diffuser bringing the flow into the wave chamber to rest. This action recovers the kinetic energy from the flow and limits any boundary layer growth. The flow is then discharged in an axial direction through an opening in the valve plate when the valve plate is rotated to an open position. The diffuser thus efficiently raises the static pressure of the fluid and discharges an axially directed flow at a radius that is predominantly below the maximum radius of the diffuser.

  11. Centrifugal compressor tip clearance and impeller flow

    Jaatinen-Varri, Ahti; Tiainen, Jonna; Turunen-Saaresti, Teemu; Gronman, Aki; Ameli, Alireza; Backman, Jari [Laboratory of Fluid Dynamics, LUT School of Energy Systems, Lappeenranta University of Technology, Lappeenranta (Finland); Engeda, Abraham [Turbomachinery Laboratory, Dept. of Mechanical Engineering, Michigan State University, East Lansing (United States)

    2016-11-15

    Compressors consume a considerable portion of the electricity used in the industrial sector. Hence, improvements in compressor efficiency lead to energy savings and reduce environmental impacts. The efficiency of an unshrouded centrifugal compressor suffers from leakage flow over the blade tips. The effect of tip leakage flow on the passage flow differs between the full and splitter blade passages. In this study, the differences in the flow fields between the full and splitter blade passages were studied numerically in detail. An industrial high-speed compressor with a design pressure ratio of 1.78 was modelled. Numerical studies were conducted with six different tip clearances and three different diffuser widths. The results show that increasing tip clearance considerably increases the reversed flow into the impeller with an unpinched diffuser. The reversed flow then partly mixes into the flow in the same blade passage it entered the impeller and the rest migrates over the blade, mixing with the tip clearance flow. Furthermore, as the reversed and clearance flow mix into the wake, the wake is weakened. As pinch reduces both the reversed flow and clearance flow, the passage wakes are stronger with pinches. However, the pinch is beneficial as the losses at the impeller outlet decrease.

  12. Centrifugal compressor tip clearance and impeller flow

    Jaatinen-Varri, Ahti; Tiainen, Jonna; Turunen-Saaresti, Teemu; Gronman, Aki; Ameli, Alireza; Backman, Jari; Engeda, Abraham

    2016-01-01

    Compressors consume a considerable portion of the electricity used in the industrial sector. Hence, improvements in compressor efficiency lead to energy savings and reduce environmental impacts. The efficiency of an unshrouded centrifugal compressor suffers from leakage flow over the blade tips. The effect of tip leakage flow on the passage flow differs between the full and splitter blade passages. In this study, the differences in the flow fields between the full and splitter blade passages were studied numerically in detail. An industrial high-speed compressor with a design pressure ratio of 1.78 was modelled. Numerical studies were conducted with six different tip clearances and three different diffuser widths. The results show that increasing tip clearance considerably increases the reversed flow into the impeller with an unpinched diffuser. The reversed flow then partly mixes into the flow in the same blade passage it entered the impeller and the rest migrates over the blade, mixing with the tip clearance flow. Furthermore, as the reversed and clearance flow mix into the wake, the wake is weakened. As pinch reduces both the reversed flow and clearance flow, the passage wakes are stronger with pinches. However, the pinch is beneficial as the losses at the impeller outlet decrease

  13. NECESSARY CONDITIONS OF STABILITY MOVING PARTS OF ROTOR CENTRIFUGE

    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. Sand characterization by combined centrifuge and laboratory tests

    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 ...

  15. Experimental Study on Noise Characteristic of Centrifugal Compressor Surge

    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 ...

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

    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)

  17. Designing and modeling a centrifugal microfluidic device to separate target blood cells

    Shamloo, Amir; Selahi, AmirAli; Madadelahi, Masoud

    2016-01-01

    The objective of this study is to design a novel and efficient portable lab-on-a-CD (LOCD) microfluidic device for separation of specific cells (target cells) using magnetic beads. In this study the results are shown for neutrophils as target cells. However, other kinds of target cells can be separated in a similar approach. The designed microfluidics can be utilized as a point of care system for neutrophil detection. This microfluidic system employs centrifugal and magnetic forces for separation. After model validation by the experimental data in the literature (that may be used as a design tool for developing centrifugo-magnetophoretic devices), two models are presented for separation of target cells using magnetic beads. The first model consists of one container in the inlet section and two containers in the outlets. Initially, the inlet container is filled with diluted blood sample which is a mixture of red blood cells (RBCs) plus neutrophils which are attached to Magnetic beads. It is shown that by using centrifugal and magnetic forces, this model can separate all neutrophils with recovery factor of ∼100%. In the second model, due to excess of magnetic beads in usual experimental analysis (to ensure that all target cells are attached to them) the geometry is improved by adding a third outlet for these free magnetic beads. It is shown that at angular velocity of 45 rad s −1 , recovery factor of 100% is achievable for RBCs, free magnetic beads and neutrophils as target cells. (paper)

  18. Designing and modeling a centrifugal microfluidic device to separate target blood cells

    Shamloo, Amir; Selahi, AmirAli; Madadelahi, Masoud

    2016-03-01

    The objective of this study is to design a novel and efficient portable lab-on-a-CD (LOCD) microfluidic device for separation of specific cells (target cells) using magnetic beads. In this study the results are shown for neutrophils as target cells. However, other kinds of target cells can be separated in a similar approach. The designed microfluidics can be utilized as a point of care system for neutrophil detection. This microfluidic system employs centrifugal and magnetic forces for separation. After model validation by the experimental data in the literature (that may be used as a design tool for developing centrifugo-magnetophoretic devices), two models are presented for separation of target cells using magnetic beads. The first model consists of one container in the inlet section and two containers in the outlets. Initially, the inlet container is filled with diluted blood sample which is a mixture of red blood cells (RBCs) plus neutrophils which are attached to Magnetic beads. It is shown that by using centrifugal and magnetic forces, this model can separate all neutrophils with recovery factor of ~100%. In the second model, due to excess of magnetic beads in usual experimental analysis (to ensure that all target cells are attached to them) the geometry is improved by adding a third outlet for these free magnetic beads. It is shown that at angular velocity of 45 rad s-1, recovery factor of 100% is achievable for RBCs, free magnetic beads and neutrophils as target cells.

  19. Particle attraction effects on the centrifugal casting and extrusion of alumina

    Schilling, C.H.; Bergstroem, L.; Ker, H.L.; Aksay, I.A.

    1993-01-01

    Interparticle attraction forces were empirically related to the centrifugal casting and extrusion behavior of flocculated alumina suspensions. Attractive forces were altered by two approaches: Salt flocculation, which entails regulating the electrical double-layer thickness through electrolyte additions; and screening of van der Waals attraction by steric interactions of surface-adsorbed fatty acids. Specimens produced by both compressibility at a critical maximum density that increased with decreasing interparticle attraction. Gradients in packing density during centrifugal casting were alleviated using both methods as long as spatial variations of the effective stress were within the low-compressibility range. We hypothesized that the reduced interparticle attraction in both methods may also raise the threshold packing density at which ductile-to-brittle transitions occur during plastic shear. Specimens prepared with oleic acid adlayers were highly plastic and easily extrudable at solids contents of up to 59 vol%, although salt-flocculated samples at 55 vol% density extruded at creeping flow rates that were insensitive to the applied pressure. Results suggested that particle rearrangement during shear, is a rate-limiting process, with an average relaxation time that is lowered by reducing interparticle attraction

  20. Comparison of the compressive yield response of aggregated suspensions: Pressure filtration, centrifugation, and osmotic consolidation

    Miller, K.T.; Melant, R.M.; Zukoski, C.F.

    1996-01-01

    The compressive rheological responses of suspensions containing flocculated kaolin, alumina (average particle sizes of 0.2 and 0.5 microm), and hydrous zirconia (average particle sizes of 8, 57, and 139 nm) particles have been measured using three different techniques: pressure filtration, volume fraction profile during centrifugation, and sediment height during centrifugation at multiple spinning speeds. While the volume fraction profile technique appears to be experimentally most robust, equivalent responses are found using the different techniques, indicating that the compressive yield stress is a material property of a given suspension. The compressive yield stress of each suspension increases rapidly with volume fraction but cannot be generally described using simple power-law or exponential fits. The compressive yield stress also increases with the inverse square of particle size. The packing behavior of the suspensions undergoing osmotic consolidation is compared with the mechanical compressive yield response. Some suspensions exhibited the same packing behavior as in the mechanical techniques, while others consistently packed to higher densities during osmotic consolidation. Although equivalent osmotic and mechanical loads do not always result in the same volume fractions, the similar increases in volume fraction with applied driving force suggest that both the osmotic and mechanical techniques are controlled by the force needed to rearrange the particle network

  1. Flow induced vibrations in gas tube assembly of centrifuge

    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)

  2. Effect of Centrifuge Temperature on Routine Coagulation Tests.

    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.

  3. Considerations on safeguards approach for small centrifuge enrichment facilities

    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)

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

    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...

  5. Uplifting behavior of shallow buried pipe in liquefiable soil by dynamic centrifuge test.

    Huang, Bo; Liu, Jingwen; Lin, Peng; Ling, Daosheng

    2014-01-01

    Underground pipelines are widely applied in the so-called lifeline engineerings. It shows according to seismic surveys that the damage from soil liquefaction to underground pipelines was the most serious, whose failures were mainly in the form of pipeline uplifting. In the present study, dynamic centrifuge model tests were conducted to study the uplifting behaviors of shallow-buried pipeline subjected to seismic vibration in liquefied sites. The uplifting mechanism was discussed through the responses of the pore water pressure and earth pressure around the pipeline. Additionally, the analysis of force, which the pipeline was subjected to before and during vibration, was introduced and proved to be reasonable by the comparison of the measured and the calculated results. The uplifting behavior of pipe is the combination effects of multiple forces, and is highly dependent on the excess pore pressure.

  6. Uplifting Behavior of Shallow Buried Pipe in Liquefiable Soil by Dynamic Centrifuge Test

    Bo Huang

    2014-01-01

    Full Text Available Underground pipelines are widely applied in the so-called lifeline engineerings. It shows according to seismic surveys that the damage from soil liquefaction to underground pipelines was the most serious, whose failures were mainly in the form of pipeline uplifting. In the present study, dynamic centrifuge model tests were conducted to study the uplifting behaviors of shallow-buried pipeline subjected to seismic vibration in liquefied sites. The uplifting mechanism was discussed through the responses of the pore water pressure and earth pressure around the pipeline. Additionally, the analysis of force, which the pipeline was subjected to before and during vibration, was introduced and proved to be reasonable by the comparison of the measured and the calculated results. The uplifting behavior of pipe is the combination effects of multiple forces, and is highly dependent on the excess pore pressure.

  7. Uplifting Behavior of Shallow Buried Pipe in Liquefiable Soil by Dynamic Centrifuge Test

    Liu, Jingwen; Ling, Daosheng

    2014-01-01

    Underground pipelines are widely applied in the so-called lifeline engineerings. It shows according to seismic surveys that the damage from soil liquefaction to underground pipelines was the most serious, whose failures were mainly in the form of pipeline uplifting. In the present study, dynamic centrifuge model tests were conducted to study the uplifting behaviors of shallow-buried pipeline subjected to seismic vibration in liquefied sites. The uplifting mechanism was discussed through the responses of the pore water pressure and earth pressure around the pipeline. Additionally, the analysis of force, which the pipeline was subjected to before and during vibration, was introduced and proved to be reasonable by the comparison of the measured and the calculated results. The uplifting behavior of pipe is the combination effects of multiple forces, and is highly dependent on the excess pore pressure. PMID:25121140

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

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

    2015-10-01

    For the production of bio active compounds, e.g., active enzymes or antibodies, a conserved purification process with a minimum loss of active compounds is necessary. In centrifugal partition chromatography (CPC), the separation effect is based on the different distribution of the components to be separated between two immiscible liquid phases. Thereby, one liquid phase is kept stationary in chambers by a centrifugal field and the mobile phase is pumped through via connecting ducts. Aqueous two phase systems (ATPS) are known to provide benign conditions for biochemical products and seem to be promising when used in CPC for purification tasks. However, it is not known if active biochemical compounds can "survive" the conditions in a CPC where strong shear forces can occur due to the two-phasic flow under centrifugal forces. Therefore, this aspect has been faced within this study by the separation of active laccases from a fermentation broth of Pleurotus sapidus. After selecting a suitable ATPS and operating conditions, the activity yield was calculated and the preservation of the active enzymes could be observed. Therefore, CPC could be shown as potentially suitable for the purification of bio-active compounds. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Polar representation of centrifugal pump homologous curves

    Veloso, Marcelo Antonio; Mattos, Joao Roberto Loureiro de

    2008-01-01

    Essential for any mathematical model designed to simulate flow transient events caused by pump operations is the pump performance data. The performance of a centrifugal pump is characterized by four basic parameters: the rotational speed, the volumetric flow rate, the dynamic head, and the hydraulic torque. Any one of these quantities can be expressed as a function of any two others. The curves showing the relationships between these four variables are called the pump characteristic curves, also referred to as four-quadrant curves. The characteristic curves are empirically developed by the pump manufacturer and uniquely describe head and torque as functions of volumetric flow rate and rotation speed. Because of comprising a large amount of points, the four-quadrant configuration is not suitable for computational purposes. However, it can be converted to a simpler form by the development of the homologous curves, in which dynamic head and hydraulic torque ratios are expressed as functions of volumetric flow and rotation speed ratios. The numerical use of the complete set of homologous curves requires specification of sixteen partial curves, being eight for the dynamic head and eight for the hydraulic torque. As a consequence, the handling of homologous curves is still somewhat complicated. In solving flow transient problems that require the pump characteristic data for all the operation zones, the polar form appears as the simplest way to represent the homologous curves. In the polar method, the complete characteristics of a pump can be described by only two closed curves, one for the dynamic head and other for the hydraulic torque, both in function of a single angular coordinate defined adequately in terms of the quotient between volumetric flow ratio and rotation speed ratio. The usefulness and advantages of this alternative method are demonstrated through a practical example in which the homologous curves for a pump of the type used in the main coolant loops of a

  10. Parametric representation of centrifugal pump homologous curves

    Veloso, Marcelo A.; Mattos, Joao R.L. de

    2015-01-01

    Essential for any mathematical model designed to simulate flow transient events caused by pump operations is the pump performance data. The performance of a centrifugal pump is characterized by four basic quantities: the rotational speed, the volumetric flow rate, the dynamic head, and the hydraulic torque. The curves showing the relationships between these four variables are called the pump characteristic curves. The characteristic curves are empirically developed by the pump manufacturer and uniquely describe head and torque as functions of volumetric flow rate and rotation speed. Because of comprising a large amount of points, this configuration is not suitable for computational purposes. However, it can be converted to a simpler form by the development of the homologous curves, in which dynamic head and hydraulic torque ratios are expressed as functions of volumetric flow and rotation speed ratios. The numerical use of the complete set of homologous curves requires specification of sixteen partial curves, being eight for the dynamic head and eight for the hydraulic torque. As a consequence, the handling of homologous curves is still somewhat complicated. In solving flow transient problems that require the pump characteristic data for all the operation zones, the parametric form appears as the simplest way to deal with the homologous curves. In this approach, the complete characteristics of a pump can be described by only two closed curves, one for the dynamic head and other for the hydraulic torque, both in function of a single angular coordinate defined adequately in terms of the quotient between volumetric flow ratio and rotation speed ratio. The usefulness and advantages of this alternative method are demonstrated through a practical example in which the homologous curves for a pump of the type used in the main coolant loops of a pressurized water reactor (PWR) are transformed to the parametric form. (author)

  11. Flow Range of Centrifugal Compressor Being Extended

    Skoch, Gary J.

    2001-01-01

    General Aviation will benefit from turbine engines that are both fuel-efficient and reliable. Current engines fall short of their potential to achieve these attributes. The reason is compressor surge, which is a flow stability problem that develops when the compressor is subjected to conditions that are outside of its operating range. Compressor surge can occur when fuel flow to the engine is increased, temporarily back pressuring the compressor and pushing it past its stability limit, or when the compressor is subjected to inlet flow-field distortions that may occur during takeoff and landing. Compressor surge can result in the loss of an aircraft. As a result, engine designers include a margin of safety between the operating line of the engine and the stability limit line of the compressor. Unfortunately, the most efficient operating line for the compressor is usually closer to its stability limit line than it is to the line that provides an adequate margin of safety. A wider stable flow range will permit operation along the most efficient operating line of the compressor, improving the specific fuel consumption of the engine and reducing emissions. The NASA Glenn Research Center is working to extend the stable flow range of the compressor. Significant extension has been achieved in axial compressors by injecting air upstream of the compressor blade rows. Recently, the technique was successfully applied to a 4:1 pressure ratio centrifugal compressor by injecting streams of air into the diffuser. Both steady and controlled unsteady injection were used to inject air through the diffuser shroud surface and extend the range. Future work will evaluate the effect of air injection through the diffuser hub surface and diffuser vanes with the goal of maximizing the range extension while minimizing the amount of injected air that is required.

  12. Influence of centrifugation conditions on the results of 77 routine clinical chemistry analytes using standard vacuum blood collection tubes and the new BD-Barricor tubes.

    Cadamuro, Janne; Mrazek, Cornelia; Leichtle, Alexander B; Kipman, Ulrike; Felder, Thomas K; Wiedemann, Helmut; Oberkofler, Hannes; Fiedler, Georg M; Haschke-Becher, Elisabeth

    2018-02-15

    Although centrifugation is performed in almost every blood sample, recommendations on duration and g-force are heterogeneous and mostly based on expert opinions. In order to unify this step in a fully automated laboratory, we aimed to evaluate different centrifugation settings and their influence on the results of routine clinical chemistry analytes. We collected blood from 41 healthy volunteers into BD Vacutainer PST II-heparin-gel- (LiHepGel), BD Vacutainer SST II-serum-, and BD Vacutainer Barricor heparin-tubes with a mechanical separator (LiHepBar). Tubes were centrifuged at 2000xg for 10 minutes and 3000xg for 7 and 5 minutes, respectively. Subsequently 60 and 21 clinical chemistry analytes were measured in plasma and serum samples, respectively, using a Roche COBAS instrument. High sensitive Troponin T, pregnancy-associated plasma protein A, ß human chorionic gonadotropin and rheumatoid factor had to be excluded from statistical evaluation as many of the respective results were below the measuring range. Except of free haemoglobin (fHb) measurements, no analyte result was altered by the use of shorter centrifugation times at higher g-forces. Comparing LiHepBar to LiHepGel tubes at different centrifugation setting, we found higher lactate-dehydrogenase (LD) (P = 0.003 to centrifuged at higher speed (3000xg) for a shorter amount of time (5 minutes) without alteration of the analytes tested in this study. When using LiHepBar tubes for blood collection, a separate LD reference value might be needed.

  13. Shape Optimization of Impeller Blades for 15,000 HP Centrifugal Compressor Using Fluid Structural Interaction Analysis

    Kang, Hyun Su; Oh, Jeongsu; Han, Jeong Sam

    2014-01-01

    This paper discusses a one-way fluid structural interaction (FSI) analysis and shape optimization of the impeller blades for a 15,000 HP centrifugal compressor using the response surface method (RSM). Because both the aerodynamic performance and the structural safety of the impeller are affected by the shape of its blades, shape optimization is necessary using the FSI analysis, which includes a structural analysis for the induced fluid pressure and centrifugal force. The FSI analysis is performed in ANSYS Workbench: ANSYS CFX is used for the flow field and ANSYS Mechanical is used for the structural field. The response surfaces for the FSI results (efficiency, pressure ratio, maximum stress, etc.) generated based on the design of experiments (DOE) are used to find an optimal shape for the impeller blades, which provides the maximum aerodynamic performance subject to the structural safety constraints

  14. Shape Optimization of Impeller Blades for 15,000 HP Centrifugal Compressor Using Fluid Structural Interaction Analysis

    Kang, Hyun Su [Sungkyunkwan University, Suwon (Korea, Republic of); Oh, Jeongsu [Daejoo Machinery Co., Daegu (Korea, Republic of); Han, Jeong Sam [Andong National University, Andong (Korea, Republic of)

    2014-06-15

    This paper discusses a one-way fluid structural interaction (FSI) analysis and shape optimization of the impeller blades for a 15,000 HP centrifugal compressor using the response surface method (RSM). Because both the aerodynamic performance and the structural safety of the impeller are affected by the shape of its blades, shape optimization is necessary using the FSI analysis, which includes a structural analysis for the induced fluid pressure and centrifugal force. The FSI analysis is performed in ANSYS Workbench: ANSYS CFX is used for the flow field and ANSYS Mechanical is used for the structural field. The response surfaces for the FSI results (efficiency, pressure ratio, maximum stress, etc.) generated based on the design of experiments (DOE) are used to find an optimal shape for the impeller blades, which provides the maximum aerodynamic performance subject to the structural safety constraints.

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

    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

  16. Tolerance of centrifuge-simulated suborbital spaceflight in subjects with implanted insulin pumps.

    Levin, Dana R; Blue, Rebecca S; Castleberry, Tarah L; Vanderploeg, James M

    2015-04-01

    With commercial spaceflight comes the possibility of spaceflight participants (SFPs) with significant medical conditions. Those with previously untested medical conditions, such as diabetes mellitus (DM) and the use of indwelling medical devices, represent a unique challenge. It is unclear how SFPs with such devices will react to the stresses of spaceflight. This case report describes two subjects with Type I DM using insulin pumps who underwent simulated dynamic phases of spaceflight via centrifuge G force exposure. Two Type I diabetic subjects with indwelling Humalog insulin pumps, a 23-yr-old man averaging 50 u of Humalog daily and a 27-yr-old man averaging 60 u of Humalog daily, underwent seven 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). Data collected included blood pressure, electrocardiogram, pulse oximetry, neurovestibular evaluation, and questionnaires regarding motion sickness, disorientation, greyout, and other symptoms. Neither subject experienced adverse clinical responses to the centrifuge exposure. Both maintained blood glucose levels between 110-206 mg · dl(-1). Potential risks to SFPs with insulin pump dependent DM include hypo/hyperglycemia, pump damage, neurovestibular dysfunction, skin breakdown, and abnormal stress responses. A search of prior literature did not reveal any previous studies of individuals with DM on insulin pumps exposed to prolonged accelerations. These cases suggest that individuals with conditions dependent on continuous medication delivery might tolerate the accelerations anticipated for commercial spaceflight.

  17. Effect of centrifugation on dynamic susceptibility of magnetic fluids

    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.

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

    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

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

    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.)

  20. Theory of uranium enrichment by the gas centrifuge

    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.

  1. Effect of centrifugation on dynamic susceptibility of magnetic fluids

    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.

  2. Development of centrifugal contactor for FBR fuel reprocessing

    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)

  3. Centrifuge modelling - migration of radionuclides from engineered trenches

    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)

  4. Unattended safeguards instrumentation at centrifuge enrichment plants

    Smith, L. Eric; Lebrun, Alain R.; Labella, Rocco

    2014-01-01

    As global uranium enrichment capacity under international safeguards expands, the International Atomic Energy Agency (IAEA) is challenged to develop effective safeguards approaches at gaseous centrifuge enrichment plants, particularly high‑capacity plants, while working within budgetary constraints. New safeguards approaches should meet the high‑level verification objectives for such facilities (i.e., timely detection of: diversion of declared material, excess production beyond declared amounts, and production of enrichment levels higher than declared), but should also strive for efficiency advantages in implementation, for both the IAEA and operators. Under the Agency’s State- level approach to safeguards implementation, the Agency needs a flexible toolbox of technologies, allowing tailoring of safeguards measures for each individual enrichment facility. In this paper, the potential roles and development status for three different types of unattended measurement instrumentation are discussed. On‑Line Enrichment Monitors (OLEM) could provide continuous enrichment measurement for 100% of the declared gas flowing through unit header pipes. Unattended Cylinder Verification Stations (UCVS) could provide unattended verification of the declared uranium mass and enrichment of 100% of the cylinders moving through the plant, but also apply and verify an ‘NDA Fingerprint’ to preserve verification knowledge on the contents of each cylinder throughout its life in the facility. Sharing of the operator’s load cell signals from feed and withdrawal stations could count all cylinders introduced to the process and provide periodic monitoring of the uranium mass balance for in‑process material. The integration of load cell, OLEM and UCVS data streams offers the possibility for 100% verification of declared cylinder flow, and enables the periodic verification of the declared 235 U mass balance in the plant. These new capabilities would enhance the IAEA

  5. Monodisperse Multidimensional Nanostructures via Centrifugal Separation

    Shin, Yu Jin

    Anisotropic nanomaterials, including zero-dimensional metallic nanoparticles (MNPs), one-dimensional single-walled carbon nanotubes (SWCNTs), and two-dimensional few-layer black phosphorous (FL-P) exhibit interesting structure-dependent properties that could be exploited in biomedicine, plasmonics, and optoelectronics. In this thesis, centrifugation sorting of these nanomaterials is utilized for structure refinement, investigation of structure-dependent optical response, and applications in biomedical imaging and plasmonics. Nobel NMPs show unique shape- and size-dependent optical properties. Controlled synthetic methods are developed to manipulate the structure of these NMPs, but intrinsically produce dispersions of polydisperse NPs with various shape and size, and synthetic byproducts. Here, we describe a facile strategy for separating small (edge length 80%) and subsequently achieve a 2.5 fold enhancement in refractive index sensitivity, comparable to the unsorted mixture. This shallow DGC approach is robust and reliable, and therefore can be applied to other metal nanostructures for concomitant improvements in plasmonic properties and applications. Using the identical separation strategy in the previous study, we are able to enrich gold nanostars as a function of branch number. In particular, we explore different variants of density gradient media to ensure compatibility with the star shape and colloid stability. We determine that sucrose is compatible with nanostars stability and surface functionalizaton. The refined population of gold stars are functionalized with Gd(III)-DNA to act as MRI contrast agents, and thus enables us to investigate how populations of nanostars with different branch numbers contribute to the relaxivity of surface bound Gd(III)-DNA. It is shown that the increased relaxivity of DNA-Gd star is correlated with increased number of star branches, not with increased size of the stars. Therefore, shape is a new parameter which can be tuned in

  6. Centrifuge Study of Pilot Tolerance to Acceleration and the Effects of Acceleration on Pilot Performance

    Creer, Brent Y.; Smedal, Harald A.; Wingrove, Rodney C.

    1960-01-01

    A research program the general objective of which was to measure the effects of various sustained accelerations on the control performance of pilots, was carried out on the Aviation Medical Acceleration Laboratory centrifuge, U.S. Naval Air Development Center, Johnsville, PA. The experimental setup consisted of a flight simulator with the centrifuge in the control loop. The pilot performed his control tasks while being subjected to acceleration fields such as might be encountered by a forward-facing pilot flying an atmosphere entry vehicle. The study was divided into three phases. In one phase of the program, the pilots were subjected to a variety of sustained linear acceleration forces while controlling vehicles with several different sets of longitudinal dynamics. Here, a randomly moving target was displayed to the pilot on a cathode-ray tube. For each combination of acceleration field and vehicle dynamics, pilot tracking accuracy was measured and pilot opinion of the stability and control characteristics was recorded. Thus, information was obtained on the combined effects of complexity of control task and magnitude and direction of acceleration forces on pilot performance. These tests showed that the pilot's tracking performance deteriorated markedly at accelerations greater than about 4g when controlling a lightly damped vehicle. The tentative conclusion was also reached that regardless of the airframe dynamics involved, the pilot feels that in order to have the same level of control over the vehicle, an increase in the vehicle dynamic stability was required with increases in the magnitudes of the acceleration impressed upon the pilot. In another phase, boundaries of human tolerance of acceleration were established for acceleration fields such as might be encountered by a pilot flying an orbital vehicle. A special pilot restraint system was developed to increase human tolerance to longitudinal decelerations. The results of the tests showed that human tolerance

  7. Subatomic forces

    Sutton, C.

    1989-01-01

    Inside the atom, particles interact through two forces which are never felt in the everyday world. But they may hold the key to the Universe. These ideas on subatomic forces are discussed with respect to the strong force, the electromagnetic force and the electroweak force. (author)

  8. Theory on a partially ionized gas centrifuge

    Berg, M.S. van den.

    1982-01-01

    This thesis contains a study of some flow processes occurring in the Gaswhirl experiments. In this apparatus a partially ionized gas is forced into rotation by an azimuthal electromagnetic force. After a short introduction in which a motivation is given of our research project, a comprehensive treatment is presented of the principle of rotating plasmas. Further, a historical review is given of rotating plasma systems. A derivation of the fundamental equations is given which describe the flow system mathematically and these are applied to rotating plasmas. The occurrence of secondary flows with radial and axial components is considered. This qualitative picture of secondary whirls is confirmed by measurements reported in the next chapter. The last chapter offers a possible explanation of the occurrence of the transition process in the Gaswhirl apparatus. (Auth.)

  9. Separation of gold nanorods by viscosity gradient centrifugation

    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)

  10. Numerical optimization for separation power of gas centrifuge

    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)

  11. Detection of outliers in a gas centrifuge experimental data

    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.

  12. Uranium enrichment in Europe by the gas centrifuge process

    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

  13. Centrifuge Techniques and Apparatus for Transport Experiments in Porous Media

    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.

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

    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.

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

    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.

  16. Design Optimization of a Centrifugal Fan with Splitter Blades

    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.

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

    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. Model tests of geosynthetic reinforced slopes in a geotechnical centrifuge

    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

  19. The new centrifuge high-speed pellet injector for ASDEX Upgrade

    Lang, P.T.; Andelfinger, C.; Beck, W.; Buchelt, E.; Buechl, K.; Cierpka, P.; Kollotzek, H.; Lang, R.S.; Prausner, G.; Soeldner, F.X.; Ulrich, M.; Weber, G.

    1993-04-01

    We report on the new pellet injection system for refuelling the ASDEX Upgrade tokamak with cubic H 2 or D 2 pellets having alternative side lengths of 1.5, 1.75 and 2.0 mm and optional Ne doping. The system delivers series of about one hundred pellets at a maximum repetition rate of more than 40 Hz. The pellets are accelerated by means of a centrifuge with an optimized straight acceleration arm. This configuration minimizes the compulsive force acting on the pellet during the acceleration process. Since this also minimizes stresses inside the pellet, high velocities - a maximum of 1211 m/s being achieved - are possible without destroying the hydrogen cubes. A special pellet feed-in technique based on a static stop cylinder interrupting the acceleration path successfully reduced the horizontal scattering angle to values of less than ± 4 degrees. Thus, a high efficiency - with more than 90% of the pellets arriving within the acceptance angle - was achieved without using a guide tube. The whole system was found to work very reliably and reproducibly during the whole test operation period, covering about 10 5 pellet shots. The new centrifuge, now integrated into the ASDEX Upgrade setup, has proved to be a reliable unit even for long operation periods thus affording the possibility of quasicontinuous particle refuelling throughout a plasma discharge in ASDEX Upgrade. (orig.)

  20. Unsteady influence of Self Recirculation Casing Treatment (SRCT) on high pressure ratio centrifugal compressor

    Mingyang, Yang; Ricardo, Martines-botas; Kangyao, Deng; Yangjun, Zhang; Xinqian, Zheng

    2016-01-01

    Highlights: • Reduced order model proves flow flucturations in impeller to be downstream disturbance propagation. • Fluctuations depression is attributed by the effect of energy bypass via rear slot of SRCT. • Flow distortion in diffuser results in disturbance with swing flow direction due to unbalanced forces. - Abstract: Self-Recirculation-Casing-Treatment (SRCT) is a widely employed method to enhance aerodynamic stability of a centrifugal compressor. This paper investigated unsteady effects of SRCT on the flow in a transonic centrifugal compressor via numerical method validated by experimental test. Firstly the static pressure distribution in the compressor without SRCT is measured for information of boundary conditions as well as validation. Then a 1-D unsteady model of a single passage is built and validated based on the experimental results. Next, the 1-D model of a passage with SRCT is built to investigate the unsteady influence of the SRCT on the flow in the passage. Finally 3-D unsteady CFD is employed to investigate the detailed influence of SRCT on the flow field in impeller passages. Results show that the topology of the passage with SRCT can remarkably damp the distortion propagating from downstream, hence depress the magnitude of the inlet flow distortion. Furthermore, the width of the rear slot in SRCT is the key factor for the damping effect. The 3-D simulation results further show that the fluctuations of the re-circulated flow rate via the front slot is depressed by the SRCT which is attributed to the damping effect of its configuration.

  1. Study on the Performance of a Centrifugal Compressor Using Fluid-Structure Interaction Method

    Lee Horim; Hwang, Yoonjei; Jeong, Jinhee [LG Electronics, Seoul (Korea, Republic of); Kim, Changhee; Yang, Jangsik; Son, Changmin [Pusan Nat’l Univ., Busan (Korea, Republic of)

    2016-06-15

    In this study, we perform a series of aero-thermo-mechanical analyses to predict the running-tip clearance and the effects of impeller deformation on the performance using a centrifugal compressor. During operation, the impeller deformation due to a combination of the centrifugal force, aerodynamic pressure and the thermal load results in a non-uniform tip clearance profile. For the prediction, we employ the one-way fluid-structure interaction (FSI) method using CFX 14.5 and ANSYS. The predicted running tip clearance shows a non-uniform profile over the entire flow passage. In particular, a significant reduction of the tip clearance height occurred at the leading and trailing edges of the impeller. Because of the reduction of the tip clearance, the tip leakage flow decreased by 19.4% In addition, the polytrophic efficiency under operating conditions increased by 0.72%. These findings confirm that the prediction of the running tip clearance and its impact on compressor performance is an important area that requires further investigation.

  2. Study on the Performance of a Centrifugal Compressor Using Fluid-Structure Interaction Method

    Lee Horim; Hwang, Yoonjei; Jeong, Jinhee; Kim, Changhee; Yang, Jangsik; Son, Changmin

    2016-01-01

    In this study, we perform a series of aero-thermo-mechanical analyses to predict the running-tip clearance and the effects of impeller deformation on the performance using a centrifugal compressor. During operation, the impeller deformation due to a combination of the centrifugal force, aerodynamic pressure and the thermal load results in a non-uniform tip clearance profile. For the prediction, we employ the one-way fluid-structure interaction (FSI) method using CFX 14.5 and ANSYS. The predicted running tip clearance shows a non-uniform profile over the entire flow passage. In particular, a significant reduction of the tip clearance height occurred at the leading and trailing edges of the impeller. Because of the reduction of the tip clearance, the tip leakage flow decreased by 19.4% In addition, the polytrophic efficiency under operating conditions increased by 0.72%. These findings confirm that the prediction of the running tip clearance and its impact on compressor performance is an important area that requires further investigation.

  3. Efficiency of centrifugal mechanism in producing PeV neutrinos from active galactic nuclei

    Osmanov, Zaza; Mahajan, Swadesh; Machabeli, George; Chkheidze, Nino

    2018-05-01

    A several-step theoretical model is constructed to trace the origin of ultra high energy (UHE) [ 1 - 2 ] PeV neutrinos detected, recently, by the IceCube collaboration. Protons in the AGN magnetosphere, experiencing different gravitational centrifugal force, provide free energy for the parametric excitation of Langmuir waves via a generalized two-stream instability. Landau damping of these waves, outside the AGN magnetosphere, can accelerate protons to ultra high energies. The ultimate source for this mechanism, the Langmuir-Landau-Centrifugal-Drive (LLCD), is the gravitational energy of the compact object. The LLCD generated UHE protons provide the essential ingredient in the creation of UHE neutrinos via appropriate hadronic reactions; protons of energy 1017 eV can be generated in the plasmas surrounding AGN with bolometric luminosities of the order of 1043 ergs s-1. By estimating the diffusive energy flux of extragalactic neutrinos in the energy interval [ 1 - 2 ] PeV, we find that an acceptably small fraction 0.003% of the total bolometric luminosity will suffice to create the observed fluxes of extragalactic ultra-high energy neutrinos.

  4. High-speed centrifugation induces aggregation of extracellular vesicles.

    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.

  5. Simplified simulation of multicomponent isotope separation by gas centrifuge

    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

  6. Centrifuge modelling of a laterally cyclic loaded pile

    Klinkvort, Rasmus Tofte; Leth, Caspar Thrane; Hededal, Ole

    2010-01-01

    A total number of 9 static and 6 cyclic centrifuge tests on laterally loaded piles in very dense, dry sand was erformed. The prototype dimensions of the piles were 1 meter in diameter and penetration depths varying from 6 to 10 meters. The static tests were used to investigate the initial subgrade...... reaction modulus and as a reference for cyclic tests. For the cyclic tests the accumulation of deflections and the change in secant stiffness of the soil from repetitive loading were investigated. From all the tests carried out accumulations of deflections were seen. rom the centrifuge tests it was seen...

  7. An Investigation of Backflow Phenomenon in Centrifugal Compressors

    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.

  8. High-speed centrifugation induces aggregation of extracellular vesicles

    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.

  9. Review of noise reduction methods for centrifugal fans

    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.

  10. Elements for modeling and design of centrifugal compressor housings

    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

  11. Design Method for Channel Diffusers of Centrifugal Compressors

    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.

  12. Effect of Excess Gravitational Force on Cultured Myotubes in Vitro

    Shigehiro Hashimoto

    2013-06-01

    Full Text Available An effect of an excess gravitational force on cultured myoblasts has been studied in an experimental system with centrifugal force in vitro. Mouse myoblasts (C2C12 were seeded on a culture dish of 35 mm diameter, and cultured in the Dulbecco's Modified Eagle's Medium until the sub-confluent condition. To apply the excess gravitational force on the cultured cells, the dish was set in a conventional centrifugal machine. Constant gravitational force was applied to the cultured cells for three hours. Variations were made on the gravitational force (6 G, 10 G, 100 G, 500 G, and 800 G with control of the rotational speed of the rotator in the centrifugal machine. Morphology of the cells was observed with a phasecontrast microscope for eight days. The experimental results show that the myotube thickens day by day after the exposure to the excess gravitational force field. The results also show that the higher excess gravitational force thickens myotubes. The microscopic study shows that myotubes thicken with fusion each other.

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

    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.

  14. Gas-liquid Two Phase Flow Modelling of Incompressible Fluid and Experimental Validation Studies in Vertical Centrifugal Casting

    Zhou, J X; Shen, X; Yin, Y J; Guo, Z; Wang, H

    2015-01-01

    In this paper, Gas-liquid two phase flow mathematic models of incompressible fluid were proposed to explore the feature of fluid under certain centrifugal force in vertical centrifugal casting (VCC). Modified projection-level-set method was introduced to solve the mathematic models. To validate the simulation results, two methods were used in this study. In the first method, the simulation result of basic VCC flow process was compared with its analytic solution. The relationship between the numerical solution and deterministic analytic solution was presented to verify the correctness of numerical algorithms. In the second method, systematic water simulation experiments were developed. In this initial experiment, special experimental vertical centrifugal device and casting shapes were designed to describe typical mold-filling processes in VCC. High speed camera system and data collection devices were used to capture flow shape during the mold-filling process. Moreover, fluid characteristic at different rotation speed (from 40rpm, 60rpmand 80rpm) was discussed to provide comparative resource for simulation results. As compared with the simulation results, the proposed mathematical models could be proven and the experimental design could help us advance the accuracy of simulation and further studies for VCC. (paper)

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

    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.)

  16. Experiments with background gas in a vacuum arc centrifuge

    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

  17. Dictionary of centrifugal pumps. 3. rev. ed. Kreiselpumpen Lexikon

    Holzenberger, K; Jung, K [comps.

    1989-01-01

    This technical dictionary was brought up to date of the state of the art. The terminology was supplemented with terms referring to centrifugal pumps. There are now almost 700 terms, with their English and French translations. To facilitate usage all the terms of books are listed in alphabetical order at the end of the book. (RHM).

  18. Design of a piezoelectric shaker for centrifuge testing

    Canclini, J. G.; Henderson, J. M.

    1979-01-01

    The design of a prototype piezoelectric shaker and its development to date is described. Although certain design problems remain to be solved, the piezoelectric system shows promise for adaptation to a larger payload system, such as the proposed geotechnical centrifuge at the Ames Research Center.

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

    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

  20. Model Based Fault Detection in a Centrifugal Pump Application

    Kallesøe, Carsten; Cocquempot, Vincent; Izadi-Zamanabadi, Roozbeh

    2006-01-01

    A model based approach for fault detection in a centrifugal pump, driven by an induction motor, is proposed in this paper. The fault detection algorithm is derived using a combination of structural analysis, observer design and Analytical Redundancy Relation (ARR) design. Structural considerations...