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Sample records for radial flow chromatography

  1. High throughput purification of recombinant human growth hormone using radial flow chromatography.

    PubMed

    Singh, Surinder M; Sharma, Aparna; Panda, Amulya K

    2009-11-01

    Recombinant human growth hormone (r-hGH) was expressed in Escherichia coli as inclusion bodies. Using fed-batch fermentation process, around 670 mg/L of r-hGH was produced at a cell OD600 of 35. Cell lysis followed by detergent washing resulted in semi-purified inclusion bodies with more than 80% purity. Purified inclusion bodies were homogenous in preparation having an average size of 0.6 microm. Inclusion bodies were solubilized at pH 12 in presence of 2M urea and refolded by pulsatile dilution. Refolded protein was purified with DEAE-anion exchange chromatography using both radial and axial flow column (50 ml bed volume each). Higher buffer flow rate (30 ml/min) in radial flow column helped in reducing the batch processing time for purification of refolded r-hGH. Radial column based purification resulted in high throughput recovery of diluted refolded r-hGH in comparison to axial column. More than 40% of inclusion body protein could be refolded into bioactive form using the above method in a single batch. Purified r-hGH was analyzed by mass spectroscopy and found to be bioactive by Nb2 cell line proliferation assay. Inclusion body enrichment, mild solubilization, pulsatile refolding and radial flow chromatography worked co-operatively to improve the overall recovery of bioactive protein from inclusion bodies. PMID:19500673

  2. Radially spreading surface flows

    NASA Astrophysics Data System (ADS)

    Maclatchy, Michael Ray

    The present study investigated the radially spreading surface flow that is created when a vertical buoyant jet is discharged in shallow water and surfaces. Experiments were conducted for a series of vertical buoyant jets discharging into a shallow circular tank specially designed to simulate an infinite ambient water body so that downstream control effects were avoided. A range of flow rates and port diameters were utilized to determine the nature of the flow structure in the radially spreading surface region. Velocity profiles using an ADV, and temperature profiles using a thermistor array, were made throughout the radial flow region. The present study concentrated on the radial buoyant jet region of a vertical buoyant jet discharged in shallow water. In this region the surface flow rapidly entrained ambient fluid as it moved outward, and the rate at which fluid was entrained with distance was greater for the radially spreading flow than for the vertical jet itself, Both the bulk and minimum time-averaged dilutions increased linearly with radial distance. The upper layer depth increased in a parabolic fashion with radial distance, consistent with previous studies of mixing layers. The composite Froude number decreased gradually from its high initial values, but was never less than one through the entire radial extent in which measurements were made. Thus, for the range of conditions of this study the flow remained internally supercritical (on a time-averaged basis). This was also true for the stability Froude number, indicating that the radial flow was unstable and entrainment occurred throughout the radial extent investigated. No internal hydraulic jumps were found in the radially spreading surface flow in the present study. Significant entrainment into the radially spreading surface flow was found. The entrainment velocity was found to be proportional to the velocity difference between the upper and lower layers at larger radius where the radial flow had become established. The entrainment hypothesis of Morton, Taylor and Turner (1956) was consistent with the measured behaviour of the radially spreading surface flow in the present study.

  3. Radial flow heat exchanger

    DOEpatents

    Valenzuela, Javier (Hanover, NH)

    2001-01-01

    A radial flow heat exchanger (20) having a plurality of first passages (24) for transporting a first fluid (25) and a plurality of second passages (26) for transporting a second fluid (27). The first and second passages are arranged in stacked, alternating relationship, are separated from one another by relatively thin plates (30) and (32), and surround a central axis (22). The thickness of the first and second passages are selected so that the first and second fluids, respectively, are transported with laminar flow through the passages. To enhance thermal energy transfer between first and second passages, the latter are arranged so each first passage is in thermal communication with an associated second passage along substantially its entire length, and vice versa with respect to the second passages. The heat exchangers may be stacked to achieve a modular heat exchange assembly (300). Certain heat exchangers in the assembly may be designed slightly differently than other heat exchangers to address changes in fluid properties during transport through the heat exchanger, so as to enhance overall thermal effectiveness of the assembly.

  4. Radial flow pulse jet mixer

    DOEpatents

    VanOsdol, John G.

    2013-06-25

    The disclosure provides a pulse jet mixing vessel for mixing a plurality of solid particles. The pulse jet mixing vessel is comprised of a sludge basin, a flow surface surrounding the sludge basin, and a downcoming flow annulus between the flow surface and an inner shroud. The pulse jet mixing vessel is additionally comprised of an upper vessel pressurization volume in fluid communication with the downcoming flow annulus, and an inner shroud surge volume separated from the downcoming flow annulus by the inner shroud. When the solid particles are resting on the sludge basin and a fluid such as water is atop the particles and extending into the downcoming flow annulus and the inner shroud surge volume, mixing occurs by pressurization of the upper vessel pressurization volume, generating an inward radial flow over the flow surface and an upwash jet at the center of the sludge basin.

  5. Stirling Engine With Radial Flow Heat Exchangers

    NASA Technical Reports Server (NTRS)

    Vitale, N.; Yarr, George

    1993-01-01

    Conflict between thermodynamical and structural requirements resolved. In Stirling engine of new cylindrical configuration, regenerator and acceptor and rejector heat exchangers channel flow of working gas in radial direction. Isotherms in regenerator ideally concentric cylinders, and gradient of temperature across regenerator radial rather than axial. Acceptor and rejector heat exchangers located radially inward and outward of regenerator, respectively. Enables substantial increase in power of engine without corresponding increase in diameter of pressure vessel.

  6. Radial flow nuclear thermal rocket (RFNTR)

    DOEpatents

    Leyse, Carl F.

    1995-11-07

    A radial flow nuclear thermal rocket fuel assembly includes a substantially conical fuel element having an inlet side and an outlet side. An annular channel is disposed in the element for receiving a nuclear propellant, and a second, conical, channel is disposed in the element for discharging the propellant. The first channel is located radially outward from the second channel, and separated from the second channel by an annular fuel bed volume. This fuel bed volume can include a packed bed of loose fuel beads confined by a cold porous inlet frit and a hot porous exit frit. The loose fuel beads include ZrC coated ZrC-UC beads. In this manner, nuclear propellant enters the fuel assembly axially into the first channel at the inlet side of the element, flows axially across the fuel bed volume, and is discharged from the assembly by flowing radially outward from the second channel at the outlet side of the element.

  7. Radial flow nuclear thermal rocket (RFNTR)

    DOEpatents

    Leyse, Carl F.

    1995-01-01

    A radial flow nuclear thermal rocket fuel assembly includes a substantially conical fuel element having an inlet side and an outlet side. An annular channel is disposed in the element for receiving a nuclear propellant, and a second, conical, channel is disposed in the element for discharging the propellant. The first channel is located radially outward from the second channel, and separated from the second channel by an annular fuel bed volume. This fuel bed volume can include a packed bed of loose fuel beads confined by a cold porous inlet frit and a hot porous exit frit. The loose fuel beads include ZrC coated ZrC-UC beads. In this manner, nuclear propellant enters the fuel assembly axially into the first channel at the inlet side of the element, flows axially across the fuel bed volume, and is discharged from the assembly by flowing radially outward from the second channel at the outlet side of the element.

  8. Fast radial flows in transition disk holes

    SciTech Connect

    Rosenfeld, Katherine A.; Andrews, Sean M.; Chiang, Eugene

    2014-02-20

    Protoplanetary 'transition' disks have large, mass-depleted central cavities, yet also deliver gas onto their host stars at rates comparable to disks without holes. The paradox of simultaneous transparency and accretion can be explained if gas flows inward at much higher radial speeds inside the cavity than outside the cavity, since surface density (and by extension optical depth) varies inversely with inflow velocity at fixed accretion rate. Radial speeds within the cavity might even have to approach free-fall values to explain the huge surface density contrasts inferred for transition disks. We identify observational diagnostics of fast radial inflow in channel maps made in optically thick spectral lines. Signatures include (1) twisted isophotes in maps made at low systemic velocities and (2) rotation of structures observed between maps made in high-velocity line wings. As a test case, we apply our new diagnostic tools to archival Atacama Large Millimeter Array data on the transition disk HD 142527 and uncover evidence for free-fall radial velocities inside its cavity. Although the observed kinematics are also consistent with a disk warp, the radial inflow scenario is preferred because it predicts low surface densities that appear consistent with recent observations of optically thin CO isotopologues in this disk. How material in the disk cavity sheds its angular momentum wholesale to fall freely onto the star is an unsolved problem; gravitational torques exerted by giant planets or brown dwarfs are briefly discussed as a candidate mechanism.

  9. Radial Chromatography for the Separation of Nitroaniline Isomers

    ERIC Educational Resources Information Center

    Miller, Robert B.; Case, William S.

    2011-01-01

    Separation techniques are usually presented in the undergraduate organic laboratory to teach students how to purify and isolate compounds. Often the concept of liquid chromatography is introduced by having students create "silica gel columns" to separate components of a reaction mixture. Although useful, column chromatography can be a laborious

  10. Radial Chromatography for the Separation of Nitroaniline Isomers

    ERIC Educational Resources Information Center

    Miller, Robert B.; Case, William S.

    2011-01-01

    Separation techniques are usually presented in the undergraduate organic laboratory to teach students how to purify and isolate compounds. Often the concept of liquid chromatography is introduced by having students create "silica gel columns" to separate components of a reaction mixture. Although useful, column chromatography can be a laborious…

  11. Radial flow afterburner for event generators and the baryon puzzle

    NASA Astrophysics Data System (ADS)

    Cuautle, E.; Paic, G.

    2008-07-01

    A simple afterburner to add radial flow to the randomized transverse momentum obtained from event generators, PYTHIA and HIJING, has been implemented to calculate the p/π ratios and compare them with available data. A coherent trend of qualitative agreement has been obtained in pp and Au+Au collisions for various centralities. These results indicate that the radial flow does play an important role in the so-called baryon puzzle anomaly.

  12. Generation of Transmissivity Fields with Non-radial Flow Dimensions

    NASA Astrophysics Data System (ADS)

    Bowman, D. O.; Roberts, R. M.; Holt, R. M.

    2006-12-01

    Non-radial flow signatures are seen in many hydraulic tests in fractured media. The generalized radial flow approach, which uses a variable flow dimension (n), is increasingly used to interpret hydraulic tests to account for non-radial flow. Flow dimension can be estimated directly from the second derivative of pumping test drawdown versus log time and can be described as the change in cross-sectional area of flow with respect to radial distance from the borehole. Previously, it was not clear if flow dimension was an intrinsic property of a medium or an artifact of the analysis technique. Representing non-radial flow in a 2D numerical model has been problematic. As part of an effort to understand how to structure heterogeneous transmissivity to create the type of non-radial flow signatures commonly observed, we generated spatially correlated binary random transmissivity fields with directional anisotropy in the correlation length. Analysis of simulated pumping tests in these fields provided the same types of non-radial diagnostic responses commonly observed in pumping tests in a fractured dolomite at the Waste Isolation Pilot Plant (WIPP) site. Our method may provide insight into how to better conceptualize flow systems and, with further analysis and understanding, allow us to condition future transmissivity fields. Acknowledgements: This research is funded by WIPP programs administered by the Office of Environmental Management (EM) of the U.S. Department of Energy. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  13. Dynamics of a vortex pair in radial flow

    SciTech Connect

    Bannikova, E. Yu. Kontorovich, V. M. Reznik, G. M.

    2007-10-15

    The problem of vortex pair motion in two-dimensional radial flow is solved. Under certain conditions for flow parameters, the vortex pair can reverse its motion within a bounded region. The vortex-pair translational velocity decreases or increases after passing through the source/sink region, depending on whether the flow is diverging or converging, respectively. The rotational motion of a corotating vortex pair in a quiescent environment transforms into motion along a logarithmic spiral in radial flow. The problem may have applications in astrophysics and geophysics.

  14. Sugar Determination in Foods with a Radially Compressed High Performance Liquid Chromatography Column.

    ERIC Educational Resources Information Center

    Ondrus, Martin G.; And Others

    1983-01-01

    Advocates use of Waters Associates Radial Compression Separation System for high performance liquid chromatography. Discusses instrumentation and reagents, outlining procedure for analyzing various foods and discussing typical student data. Points out potential problems due to impurities and pump seal life. Suggests use of ribose as internal…

  15. Sugar Determination in Foods with a Radially Compressed High Performance Liquid Chromatography Column.

    ERIC Educational Resources Information Center

    Ondrus, Martin G.; And Others

    1983-01-01

    Advocates use of Waters Associates Radial Compression Separation System for high performance liquid chromatography. Discusses instrumentation and reagents, outlining procedure for analyzing various foods and discussing typical student data. Points out potential problems due to impurities and pump seal life. Suggests use of ribose as internal

  16. Accretion, radial flows and abundance gradients in spiral galaxies

    NASA Astrophysics Data System (ADS)

    Pezzulli, Gabriele; Fraternali, Filippo

    2016-01-01

    The metal-poor gas continuously accreting on to the discs of spiral galaxies is unlikely to arrive from the intergalactic medium (IGM) with exactly the same rotation velocity as the galaxy itself and even a small angular momentum mismatch inevitably drives radial gas flows within the disc, with significant consequences to galaxy evolution. Here, we provide some general analytic tools to compute accretion profiles, radial gas flows and abundance gradients in spiral galaxies as a function of the angular momentum of the accreting material. We generalize existing solutions for the decomposition of the gas flows, required to reproduce the structural properties of galaxy discs, into direct accretion from the IGM and a radial mass flux within the disc. We then solve the equation of metallicity evolution in the presence of radial gas flows with a novel method, based on characteristic lines, which greatly reduces the numerical demand on the computation and sheds light on the crucial role of boundary conditions on the abundance profiles predicted by theoretical models. We also discuss how structural and chemical constraints can be combined to disentangle the contributions of inside-out growth and radial flows in the development of abundance gradients in spiral galaxies. Illustrative examples are provided throughout with parameters plausible for the Milky Way. We find that the material accreting on the Milky Way should rotate at 70-80 per cent of the rotational velocity of the disc, in agreement with previous estimates.

  17. Development of radial optic flow pattern sensitivity at different speeds.

    PubMed

    Joshi, Mahesh Raj; Falkenberg, Helle K

    2015-05-01

    The development of sensitivity to radial optic flow discrimination was investigated by measuring motion coherence thresholds (MCTs) in school-aged children at two speeds. A total of 119 child observers aged 6-16years and 24 young adult observers (23.66+/-2.74years) participated. In a 2AFC task observers identified the direction of motion of a 5 radial (expanding vs. contracting) optic flow pattern containing 100 dots with 75% Michelson contrast moving at 1.6/s and 5.5/s and. The direction of each dot was drawn from a Gaussian distribution whose standard deviation was either low (similar directions) or high (different directions). Adult observers also identified the direction of motion for translational (rightward vs. leftward) and rotational (clockwise vs. anticlockwise) patterns. Motion coherence thresholds to radial optic flow improved gradually with age (linear regression, p<0.05), with different rates of development at the two speeds. Even at 16years MCTs were higher than that for adults (independent t-tests, p<0.05). Both children and adults had higher sensitivity at 5.5/s compared to 1.6/s (paired t-tests, p<0.05). Sensitivity to radial optic flow is still immature at 16years of age, indicating late maturation of higher cortical areas. Differences in sensitivity and rate of development of radial optic flow at the different speeds, suggest that different motion processing mechanisms are involved in processing slow and fast speeds. PMID:25796975

  18. Effect of the radial buoyancy on a circular Couette flow

    NASA Astrophysics Data System (ADS)

    Meyer, Antoine; Yoshikawa, Harunori N.; Mutabazi, Innocent

    2015-11-01

    The effect of a radial temperature gradient on the stability of a circular Couette flow is investigated when the gravitational acceleration is neglected. The induced radial stratification of the fluid density coupled with the centrifugal acceleration generates radial buoyancy which is centrifugal for inward heating and centripetal for outward heating. This radial buoyancy modifies the Rayleigh discriminant and induces the asymmetry between inward heating and outward heating in flow behavior. The critical modes are axisymmetric and stationary for inward heating while for outward heating, they can be oscillatory axisymmetric or nonaxisymmetric depending on fluid diffusion properties, i.e., on the Prandtl number Pr. The dependence of the critical modes on Pr is explored for different values of the radius ratio of the annulus. The power input of the radial buoyancy is compared with other power terms. The critical frequency of the oscillatory axisymmetric modes is linked to the Brunt-Visl frequency due to the density stratification in the radial gravity field induced by the rotation. These modes are associated with inertial waves. The dispersion relation of the oscillatory axisymmetric modes is derived in the vicinity of the critical conditions. A weakly nonlinear amplitude equation with a forcing term is proposed to explain the domination of these axisymmetric oscillatory modes over the stationary centrifugal mode.

  19. The vergence eye movements induced by radial optic flow

    PubMed Central

    Kodaka, Y.; Sheliga, B. M.; FitzGibbon, E. J.; Miles, F. A.

    2007-01-01

    Radial optic flow applied to large random dot patterns is known to elicit horizontal vergence eye movements at short latency, expansion causing convergence and contraction causing divergence: the Radial Flow Vergence Response (RFVR). We elicited RFVRs in human subjects by applying radial motion to concentric circular patterns whose radial luminance modulation was that of a square wave lacking the fundamental: the missing fundamental (mf) stimulus. The radial motion consisted of successive -wavelength steps, so that the overall pattern and the 4n+1 harmonics (where n=integer) underwent radial expansion (or contraction), whereas the 4n-1 harmonicsincluding the strongest Fourier component (the 3rd harmonic)underwent the opposite radial motion. Radial motion commenced only after the subject had fixated the center of the pattern. The initial RFVRs were always in the direction of the 3rd harmonic, e.g., expansion of the mf pattern causing divergence. Thus, the earliest RFVRs were strongly dependent on the motion of the major Fourier component, consistent with early spatio-temporal filtering prior to motion detection, as in the well-known energy model of motion analysis. If the radial mf stimulus was reduced to just two competing harmonicsthe 3rd and 5ththe initial RFVRs showed a nonlinear dependence on their relative contrasts: when the two harmonics differed in contrast by more than about an octave then the one with the higher contrast completely dominated the RFVRs and the one with lower contrast lost its influence: winner-take-all. We suggest that these nonlinear interactions result from mutual inhibition between the mechanisms sensing the motion of the different competing harmonics. If single radial-flow steps were used, a brief inter-stimulus interval resulted in reversed RFVRs, consistent with the idea that the motion detectors mediating these responses receive a visual input whose temporal impulse response function is strongly biphasic. Lastly, all of these characteristics of the RFVR, which we attribute to the early cortical processing of visual motion, are known to be shared by the Ocular Following Response (OFR)a conjugate tracking (version) response elicited at short-latency by linear motionand even the quantitative details are generally very similar. Thus, although the RFVR and OFR respond to very different patterns of global motionradial vs. linearthey have very similar local spatiotemporal properties as though mediated by the same low-level, local-motion detectors, which we suggest are in the striate cortex. PMID:17706738

  20. Self-sustained radial oscillating flows between parallel disks

    NASA Astrophysics Data System (ADS)

    Mochizuki, S.; Yang, W.-J.

    1985-05-01

    It is pointed out that radial flow between parallel circular disks is of interest in a number of physical systems such as hydrostatic air bearings, radial diffusers, and VTOL aircraft with centrally located downward-positioned jets. The present investigation is concerned with the problem of instability in radial flow between parallel disks. A time-dependent numerical study and experiments are conducted. Both approaches reveal the nucleation, growth, migration, and decay of annular separation bubbles (i.e. vortex or recirculation zones) in the laminar-flow region. A finite-difference technique is utilized to solve the full unsteady vorticity transport equation in the theoretical procedure, while the flow patterns in the experiments are visualized with the aid of dye-injection, hydrogen-bubble, and paraffin-mist methods. It is found that the separation and reattachment of shear layers in the radial flow through parallel disks are unsteady phenomena. The sequence of nucleation, growth, migration, and decay of the vortices is self-sustained.

  1. Longitudinal Dispersivity in a Radial Diverging Flow Field

    NASA Astrophysics Data System (ADS)

    Seaman, J. C.; Wilson, M.; Bertsch, P. M.; Aburime, S. A.

    2005-12-01

    Hydrodynamic dispersion is an important factor controlling contaminant migration in the subsurface environment. However, few comprehensive data sets exist for evaluating the impact of travel distance and site heterogeneity on solute dispersion under non-uniform flow conditions. In addition, anionic tracers are often used to estimate physical transport parameters based on an erroneous assumption of conservative (i.e., non-reactive) behavior. Therefore, a series of field experiments using tritiated water and several other commonly used hydrologic tracers (Br, Cl, FBAs) were conducted in the water-table aquifer on the U.S. Department of Energy's Savannah River Site (Aiken, SC) to evaluate solute transport processes in a diverging radial flow field. For each experiment, tracer-free groundwater was injected for approximately 24 hours at a fixed rate of 56.7 L/min (15 gpm) to establish a forced radial gradient prior to the introduction of a tracer pulse. After the tracer pulse, the forced gradient was maintained throughout the experiment using non-labeled groundwater. Tracer migration was monitored using a set of six sampling wells radially spaced at approximate distances of 1.5, 3, and 4.5 meters from a central injection well. Each sampling well was further divided into three discrete sampling depths that were monitored continuously throughout the course of the tracer experiment. At various time intervals, discrete groundwater samples were collected from all 18 sampling ports for tritium analysis. Longitudinal dispersivity for tritium breakthrough at each sampling location was estimated using analytical approximations of the convection dispersion equation (CDE) for radial flow assuming an instantaneous Dirac pulse and a pulse of known duration. The results were also compared to dispersivity values derived from fitting the tracer data to analytical solutions derived from assuming uniform flow conditions. Tremendous variation in dispersivity values and tracer arrival times were observed between wells located at similar radial distances and between sampling zones within a given well, with multiple arrival peaks observed for some monitoring locations. However, lower dispersivity values were observed for all data sets when fitting the breakthrough data using the radial flow approximations when compared to uniform flow case. In addition, the 95% confidence interval span for the dispersivity estimate was always smaller for the radial flow solution, indicating a better model fit when compared to the uniform flow model. Additional logistical obstacles in conducting such an extensive set of field tracer experiments will also be discussed.

  2. Oculomotor response to radial optic flow in infancy.

    PubMed

    Nawrot, Elizabeth; Nawrot, Mark

    2015-01-01

    Research with infants has illustrated the development of adult-like smooth pursuit gain by five months-of-age and links this to the development of sensitivity to depth from motion parallax. Ocular following response eye movements to radial optic flow stimuli may also be an indicator of sensitivity to changes in depth. An expanding flow field elicits convergent eye movements while a contracting one elicits divergent eye movements. This response suggests the visual system is interpreting the radial flow as a change in depth. We measured the oculomotor response to radial optic flow in infants across the age range where smooth pursuit gain is developing. Vergence eye movements were elicited from 56 infants 8-20 weeks-of-age. The stimulus comprised a radial optic flow pattern that expanded or contracted across eight 400 msec trials. The order of the four expanding and four contracting trials was randomized and eye position was monitored with a Tobii X120 eye-tracker. We defined the threshold for a vergence eye movement as velocity greater than 0.3 deg/sec. The majority of infants produced vergence eye movements in response to the expanding and contracting trials with about half producing either a convergence or divergence response appropriate to the stimuli. Approximately one-quarter produced both convergence and divergence responses. However, there was no relationship between age and the presence/absence of the vergence response or its velocity. We did find a significant positive correlation between age and smooth pursuit gain in a subset of these infants as expected. It may be that the vergence response is already developing at the youngest age. Similar to research on infants' reactions to looming stimuli, these results suggest that sensitivity to depth from radial optic flow may develop very early. Meeting abstract presented at VSS 2015. PMID:26326486

  3. Non-radial flow near the cometary surface

    NASA Technical Reports Server (NTRS)

    Marconi, M. L.; Mendis, D. A.

    1982-01-01

    It is shown that, as a consequence of the non-uniform temperature distribution of the cometary nucleus, large lateral pressure gradients are set up, which in turn drive strong lateral flows. However, at small heliocentric distances the onset of turbulence within a thin boundary layer destroys these steady lateral flows and the eventual outflow of gas from within the outer boundary of this layer is expected to be more or less radial. On the other hand, at large heliocentric distances, turbulence is unlikely to set in, and the lateral flows that are set up, may persist. Consequently, it is expected that the gas flow out of the cometary nucleus at these large distances to be highly non-radial.

  4. Analysis and performance of radial flow rotary dessicant dehumidifiers

    SciTech Connect

    Elsayed, M.M.; Chamkha, A.J.

    1997-02-01

    A model is developed to predict the steady periodic performance of a radial flow desiccant wheel. The model is expressed in terms of the same dimensionless parameters that are commonly used in modeling of the conventional axial flow desiccant wheel. In addition a dimensionless geometrical ratio of the volume of the matrix to the volume of the wheel core is found to affect the performance of the wheel. A finite difference technique on staggered grid is used to discretize the governing dimensionless equations. The discretized equations are solved to predict the performance of the desiccant wheel at given values of operation parameters. A sensitivity study is carried out to investigate the effect of changing any of these parameters on the performance of the wheel. The performance of the radial flow desiccant wheel having the same values of the operation parameters.

  5. Radial flow permeability testing of an argillaceous limestone.

    PubMed

    Selvadurai, A P S; Jenner, L

    2013-01-01

    Argillaceous Lindsay limestone is the geologic storage formation that will be encountered at the site for the construction of a deep ground repository in Ontario, Canada, for the storage of low to intermediate level nuclear waste. The permeability of the Lindsay limestone is a key parameter that will influence the long-term movement of radionuclides from the repository to the geosphere. This paper describes the use of both steady-state and transient radial flow laboratory tests to determine the permeability of this argillaceous limestone. The interpretation of the tests is carried out using both analytical results and computational models of flow problems that exhibit radial symmetry. The results obtained from this research investigation are compared with the data available in the literature for similar argillaceous limestones mainly found in the Lindsay (Cobourg) formation. The experiments give permeabilities in the range of 1.0 10(-22) to 1.68 10(-19) m(2) for radial flows that are oriented along bedding planes under zero axial stress. The factors influencing transient pulse tests in particular and the interpretation of the results are discussed. PMID:22489872

  6. Multiphase flow modeling in centrifugal partition chromatography.

    PubMed

    Adelmann, S; Schwienheer, C; Schembecker, G

    2011-09-01

    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. PMID:21324465

  7. Optimum design of radial flow impellers for variable load operation

    SciTech Connect

    Tuccillo, R.; Senatore, A.

    1994-12-31

    The authors present, in this paper, an improved methodology for optimum design of radial flow impellers. The base methodology was recently proposed by the authors and consisted of a mathematical optimization technique matched to a flow model based upon an inviscid ``quasi 3-D`` method linked to a prediction of the boundary layer growth along both blade and end-wall surfaces. The enhanced strategy proposed in the present paper utilizes a genetic optimization algorithm and a number of refinement steps. This allows an effective exploration of a wide range of the independent variables. The latter define the impeller geometry defined under several aspects related to blade curvature and twisting, inlet and discharge angles, axial and radial displacements. The objective of maximum in total-to-total efficiency for a given level of pressure ratio is pursued within constraints on load levels, inlet and discharge Mach numbers, peripheral velocity. In this paper, the authors also deal with the search of an impeller configuration for satisfactory performance in an assigned field of operation. Off-design could, in fact, emphasize some problems related to choking or flow separation which are satisfactory solved at the design point. The control exerted by the optimizing procedure on the flow model, also in terms of boundary layer development, is helpful for finding more impeller characteristics for a better fitting of the operating field.

  8. Characterizing gaseous flow in submicron chromatography columns.

    SciTech Connect

    Wong, Chung-Nin Channy

    2003-05-01

    Enormous interest exists to develop the next generation of an integrated microsystem for chemical and biological analysis ({mu}ChemLab{trademark}) and to further reduce the volume of the system. One approach is to scale down the size of critical components and to explore any pumping mechanism that can minimize the power requirement. Since the majority of the pumping requirement is to overcome the wall resistance in the gas chromatography (GC) column, our attention is to study the gas flow in this GC column. As the column dimension decreases, the gaseous flow will go from a continuum regime into a non-continuum regime; i.e., slip, transition, and free molecular regimes. Thus it is very important to well characterize the gaseous flow in submicron columns and to understand its flow behavior. Specifically, in this study, our focus is to investigate the effects of viscosity, rarefaction, and compressibility as the column dimension decreases. Both theoretical predictions and experimental results will be presented.

  9. Radial accretion flows on static spherically symmetric black holes

    NASA Astrophysics Data System (ADS)

    Chaverra, Eliana; Sarbach, Olivier

    2015-08-01

    We analyze the steady radial accretion of matter into a nonrotating black hole. Neglecting the self-gravity of the accreting matter, we consider a rather general class of static, spherically symmetric and asymptotically flat background spacetimes with a regular horizon. In addition to the Schwarzschild metric, this class contains certain deformation of it, which could arise in alternative gravity theories or from solutions of the classical Einstein equations in the presence of external matter fields. Modeling the ambient matter surrounding the black hole by a relativistic perfect fluid, we reformulate the accretion problem as a dynamical system, and under rather general assumptions on the fluid equation of state, we determine the local and global qualitative behavior of its phase flow. Based on our analysis and generalizing previous work by Michel, we prove that for any given positive particle density number at infinity, there exists a unique radial, steady-state accretion flow which is regular at the horizon. We determine the physical parameters of the flow, including its accretion and compression rates, and discuss their dependency on the background metric.

  10. Onset of radial flow in p+p collisions

    DOE PAGESBeta

    Jiang, Kun; Zhu, Yinying; Liu, Weitao; Chen, Hongfang; Li, Cheng; Ruan, Lijuan; Tang, Zebo; Xu, Zhangbu

    2015-02-23

    It has been debated for decades whether hadrons emerging from p+p collisions exhibit collective expansion. The signal of the collective motion in p+p collisions is not as clear as in heavy-ion collisions because of the low multiplicity and large fluctuation in p+p collisions. Tsallis Blast-Wave (TBW) model is a thermodynamic approach, introduced to handle the overwhelming correlation and fluctuation in the hadronic processes. We have systematically studied the identified particle spectra in p+p collisions from RHIC to LHC using TBW and found no appreciable radial flow in p+p collisions below √s = 900 GeV. At LHC higher energy of 7more »TeV in p+p collisions, the radial flow velocity achieves an average of (β) = 0.320 ± 0.005. This flow velocity is comparable to that in peripheral (40-60%) Au+Au collisions at RHIC. In addition, breaking of the identified particle spectra mT scaling was also observed at LHC from a model independent test.« less

  11. Onset of radial flow in p+p collisions

    DOE PAGESBeta

    Jiang, Kun; Zhu, Yinying; Liu, Weitao; Chen, Hongfang; Li, Cheng; Ruan, Lijuan; Tang, Zebo; Xu, Zhangbu

    2015-02-23

    It has been debated for decades whether hadrons emerging from p+p collisions exhibit collective expansion. The signal of the collective motion in p+p collisions is not as clear as in heavy-ion collisions because of the low multiplicity and large fluctuation in p+p collisions. Tsallis Blast-Wave (TBW) model is a thermodynamic approach, introduced to handle the overwhelming correlation and fluctuation in the hadronic processes. We have systematically studied the identified particle spectra in p+p collisions from RHIC to LHC using TBW and found no appreciable radial flow in p+p collisions below √s = 900 GeV. At LHC higher energy of 7more » TeV in p+p collisions, the radial flow velocity achieves an average of (β) = 0.320 ± 0.005. This flow velocity is comparable to that in peripheral (40-60%) Au+Au collisions at RHIC. In addition, breaking of the identified particle spectra mT scaling was also observed at LHC from a model independent test.« less

  12. Exact Convex Relaxation of Optimal Power Flow in Radial Networks

    SciTech Connect

    Gan, LW; Li, N; Topcu, U; Low, SH

    2015-01-01

    The optimal power flow (OPF) problem determines a network operating point that minimizes a certain objective such as generation cost or power loss. It is nonconvex. We prove that a global optimum of OPF can be obtained by solving a second-order cone program, under a mild condition after shrinking the OPF feasible set slightly, for radial power networks. The condition can be checked a priori, and holds for the IEEE 13, 34, 37, 123-bus networks and two real-world networks.

  13. Radial Flow Pattern of a Slow Coronal Mass Ejection

    NASA Astrophysics Data System (ADS)

    Feng, Li; Inhester, Bernd; Gan, Weiqun

    2015-06-01

    Height-time plots of the leading edge of coronal mass ejections (CMEs) have often been used to study CME kinematics. We propose a new method to analyze the CME kinematics in more detail by determining the radial mass transport process throughout the entire CME. Thus, our method is able to estimate not only the speed of the CME front but also the radial flow speed inside the CME. We have applied this method to a slow CME with an average leading edge speed of about 480 km s-1. In the Lagrangian frame, the speeds of the individual CME mass elements stay almost constant within 2 and 15 RS, the range over which we analyzed the CME. Hence, we have no evidence of net radial forces acting on parts of the CME in this range or of a pile up of mass ahead of the CME. We find evidence that the leading edge trajectory obtained by tie-pointing may gradually lag behind the Lagrangian front-side trajectories derived from our analysis. Our results also allow a much more precise estimate of the CME energy. Compared with conventional estimates using the CME total mass and leading edge motion, we find that the latter may overestimate the kinetic energy and the gravitational potential energy.

  14. A visual study of radial inward choked flow of liquid nitrogen

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Simoneau, R. J.; Hsu, Y. Y.

    1973-01-01

    A visual study of the radial inward choked flow of liquid nitrogen was conducted. Data and high speed moving pictures were obtained. The study indicated the following: (1) steady radial inward choked flow seems equivalent to steady choked flow through axisymmetric nozzles, (2) transient choked flows through the radial gap are not uniform and the discharge pattern appears as nonuniform impinging jets, and (3) the critical mass flow rate data for the transient case appear different from those of the steady case.

  15. Linear and radial flow targets for characterizing downhole flow in perforations

    SciTech Connect

    Deo, M. ); Tariq, S.M. ); Halleck, P.M. )

    1989-08-01

    Two types of sandstone targets are commonly used to test flow efficiency of shaped-charge jet perforations: linear targets, in which flow enters only the unperforated end of the cylindrical sample, and radial targets, in which flow enters through the end and sides of the sample. To determine which of these targets best represents downhole conditions, the flow distribution along the length of a perforation has been studied by three-dimensional (3D) finite-element analyses. Linear and radial laboratory targets have been compared with downhole perforations under varying conditions. For ideal perforations, the low-shot-density (LSD) case is adequately represented by the radial target, while the high-shot-density (HSD) case falls between the two targets. With realistic crushed and damaged zones, the HSD closely matches the linear target, and the LSD case falls between the two targets.

  16. Gravity-flow open tubular cation chromatography.

    PubMed

    Kubn, Petr; Pelcov, Pavlna; Kubn, Vlastimil; Klakurkov, Lenka; Dasgupta, Purnendu K

    2008-08-01

    We describe ion chromatography (IC) on open tubular cation exchange columns with a controllable capacity multilayered stationary phase architecture. The columns of relatively large bore (75 microm id) are fabricated by coating fused-silica capillaries with multiple layers of poly(butadiene-maleic acid) (PBMA) copolymer and crosslinking the deposited layers by thermally initiated radical polymerisation. Column capacity increases in a predictable manner with increase in the number of successively coated layers. Gravity flow with a modest head (< 2 m) can provide the desired separations within a reasonable period. We provide a minimalist configuration where no suppression is used, the sample is injected hydrodynamically as in CE, and detection is accomplished by an inexpensive homebuilt contactless conductivity detector or a capacitance to voltage digital converter. A 1 m long 75 microm bore column coated with two layers of PBMA allows gravity-flow open tubular IC to separate four alkali cations in < 10 min with a 1 mM tartaric acid (TA) eluent. Simultaneous separation of alkali and alkaline earth metal cations can be accomplished in less than 25 min using 1.75 mM pyridinedicarboxylic acid as an eluent. Contactless conductometric detection (C(4)D) allows LODs down to 150 nmol/L, corresponding to 30 fmol injections. Analysis of real water samples is demonstrated. PMID:18666181

  17. Thermodynamic optimization of radial MHD flow between parallel circular disks

    NASA Astrophysics Data System (ADS)

    Duharte, Guillermo Ibez; Haro, Mariano Lpez de; Garca, Sergio Cuevas

    2004-06-01

    The radial flow between two parallel circular disks is investigated with the aim to determine the optimum convective heat transfer conditions at the external disk surfaces in order to minimize the intrinsic irreversibilities. A general situation is considered where the fluid is electrically conducting and may be under the influence of a transversal magnetic field. The velocity and electric current density fields are obtained analytically and used to solve the heat transfer equation under boundary conditions of the third kind. The analysis is in the absence of fluid inertia, under creeping flow conditions (Reynolds number ? 1). A perturbation approach in order to include the convective heat transfer effects in the flow is used. The Pclet number is assumed to be small. The analytic expressions for the velocity, electric current density and temperature fields are used to calculate explicitly the global entropy generation rate. When the convective heat transfer coefficients for each wall are different, this function displays a minimum for specific heat exchange conditions. The results are shown for both the hydrodynamic and the magnetohydrodynamic cases. It is also found that the mean Nusselt number at the upper wall shows a maximum value for a given value of the Hartman number, when the dimensionless heat transfer coefficients for each disk and the Pclet number are fixed. This mean Nusselt number for maximum heat transfer is near its value for minimum entropy generation conditions.

  18. Forced-flow planar chromatography in the rear view mirror.

    PubMed

    Kalsz, Huba

    2015-03-01

    Mobile phase progress in planar stationary phase can be evoked by either external or internal forces. An internal force is capillarity, while gravity, electric field, a pump and centrifugal forces belong to external forces. Overpressured layer chromatography gives a widely used special chapter of forced-flow planar chromatography, a special bridge between high-performance liquid column chromatography and thin-layer chromatography (TLC). A simple and special rule characterizes the progress of mobile phase. Optimal efficiency is composed by the doubled effect of flow resulting from the pump-forced mobile phase (convex profile of laminar flow) and capillary forces on the dry stationary phase (concave laminar flow). This review describes the most important aspects of forced-flow TLC, including how the set-ups are developed and also the progress of detection methods used. PMID:25681205

  19. Boiling radial flow in fractures of varying wall porosity

    SciTech Connect

    Barnitt, Robb Allan

    2000-06-01

    The focus of this report is the coupling of conductive heat transfer and boiling convective heat transfer, with boiling flow in a rock fracture. A series of experiments observed differences in boiling regimes and behavior, and attempted to quantify a boiling convection coefficient. The experimental study involved boiling radial flow in a simulated fracture, bounded by a variety of materials. Nonporous and impermeable aluminum, highly porous and permeable Berea sandstone, and minimally porous and permeable graywacke from The Geysers geothermal field. On nonporous surfaces, the heat flux was not strongly coupled to injection rate into the fracture. However, for porous surfaces, heat flux, and associated values of excess temperature and a boiling convection coefficient exhibited variation with injection rate. Nucleation was shown to occur not upon the visible surface of porous materials, but a distance below the surface, within the matrix. The depth of boiling was a function of injection rate, thermal power supplied to the fracture, and the porosity and permeability of the rock. Although matrix boiling beyond fracture wall may apply only to a finite radius around the point of injection, higher values of heat flux and a boiling convection coefficient may be realized with boiling in a porous, rather than nonporous surface bounded fracture.

  20. An investigation of radial tracer flow in naturally fractured reservoirs

    SciTech Connect

    Jetzabeth, Ramirez-Sabag; Fernando, Samaniego V.; Jesus, Rivera R.; Fernando Rodriguez

    1991-01-01

    This study presents a general solution for the radial flow of tracers in naturally fractured reservoirs. Continuous and finite step injection of chemical and radioactive tracers are considered. The reservoir is treated as being composed of two regions: a mobile region where longitudinal dispersion and convection take place and a stagnant region where only diffusion and adsorption are allowed. Radioactive decay is considered in both regions. The model of this study is thoroughly compared to those previously presented in literature by Moench and Ogata, Tang et al., Chen et al., and Hsieh et al. The solution is numerically inverted by means of the Crump algorithm. A detailed validation of the model with respect to solutions previously presented and/or simplified physical conditions solutions (i.e., homogeneous case) or limit solutions (i.e., for short times) was carried out. The influence of various dimensionless parameters that enter into the solution was investigated. A discussion of results obtained through the Crump and Stehfest algorithm is presented, concluding that the Crump method provides more reliable tracer concentrations.

  1. A visual study of radial inward choked flow of liquid nitrogen.

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Simoneau, R. J.; Hsu, Y. Y.

    1973-01-01

    Data and high speed movies were acquired on pressurized subcooled liquid nitrogen flowing radially inward through a 0.0076 cm gap. The stagnation pressure ranged from 0.7 to 4 MN/sq m. Steady radial inward choked flow appears equivalent to steady choked flow through axisymmetric nozzles. Transient choked flows through the radial gap are not uniform and the discharge pattern appears as nonuniform impinging jets. The critical mass flow rate data for the transient case appear different from those for the steady case. On the mass flow rate vs pressure map, the slope and separation of the isotherms appear to be less for transient than for steady radial choked flow.

  2. Flow field thermal gradient gas chromatography.

    PubMed

    Boeker, Peter; Leppert, Jan

    2015-09-01

    Negative temperature gradients along the gas chromatographic separation column can maximize the separation capabilities for gas chromatography by peak focusing and also lead to lower elution temperatures. Unfortunately, so far a smooth thermal gradient over a several meters long separation column could only be realized by costly and complicated manual setups. Here we describe a simple, yet flexible method for the generation of negative thermal gradients using standard and easily exchangeable separation columns. The measurements made with a first prototype reveal promising new properties of the optimized separation process. The negative thermal gradient and the superposition of temperature programming result in a quasi-parallel separation of components each moving simultaneously near their lowered specific equilibrium temperatures through the column. Therefore, this gradient separation process is better suited for thermally labile molecules such as explosives and natural or aroma components. High-temperature GC methods also benefit from reduced elution temperatures. Even for short columns very high peak capacities can be obtained. In addition, the gradient separation is particularly beneficial for very fast separations below 1 min overall retention time. Very fast measurements of explosives prove the benefits of using negative thermal gradients. The new concept can greatly reduce the cycle time of high-resolution gas chromatography and can be integrated into hyphenated or comprehensive gas chromatography setups. PMID:26235451

  3. Computational investigations of axial and radial flow compressor aeromechanics

    NASA Astrophysics Data System (ADS)

    Ramakrishnan, Kishore

    The focus of this research is aeromechanics issues in advanced compressors of the type used in modern day high thrust-to-weight ratio aircraft gas turbine engines. The driving factor for the studies undertaken is the High Cycle Fatigue (HCF) failure of gas turbine blades. HCF is a key technology issue in the development and endurance of gas turbine engines that arises primarily due to resonant response of turbomachine blading to unsteady aerodynamic excitation. Because it is a truly coupled nonlinear fluid-structure problem, predicting HCF requires a unified approach to modeling both the fluid and the structure. Considering the serious nature of HCF and the inadequacy of lower order design systems to accurately predict blade vibratory stress, the need to develop advanced predictive tools is pressing. The first aspect of this research therefore addresses the development of a turbomachinery coupled fluid-structure interaction tool to predict flow-induced blade vibration. To this end, the TAM-ALE3D solver is further developed as a derivative of the ALE3D code of Lawrence Livermore National Laboratory. In the second aspect of this research, TAM-ALE3D is validated by predicting viscous blade row unsteady aerodynamics and the modal properties of the stator vane in the baseline configuration of the Purdue Transonic Compressor. It is then used to predict the vane vibratory response excited by rotor wakes at resonance, with the resulting stresses in the range expected. For radial flow compressors, a very limited knowledge base exists on the unsteady aerodynamic and aeroelastic mechanisms that result in HCF. The bulk of this research is thus directed at the understanding of these fundamental unsteady phenomena using TAM-ALE3D as an investigative tool. The energy transfer from the downstream diffuser generated forcing function to the impeller blading is addressed by means of unsteady aerodynamic and aeroelastic analyses. From these computational investigations, the details of the impeller blade excitation are elucidated, and promising directions for future research are identified.

  4. Flow control by combining radial pulsation and rotation of a cylinder in uniform flow

    NASA Astrophysics Data System (ADS)

    Oualli, H.; Hanchi, S.; Bouabdallah, A.; Gad-El-Hak, M.

    2008-11-01

    Flow visualizations and hot-wire measurements are carried out to study a circular cylinder undergoing simultaneous radial pulsation and rotation and placed in a uniform flow. The Reynolds number is in the range of 1,000--22,000, for which transition in the shear layers and near wake is expected. Our previous experimental and numerical investigations in this subcritical flow regime have established the existence of an important energy transfer mechanism from the mean flow to the fluctuations. Radial pulsations cause and enhance that energy transfer. Certain values of the amplitude and frequency of the pulsations lead to negative drag (i.e. thrust). The nonlinear interaction between the Magnus effect induced by the steady rotation of the cylinder and the near-wake modulated by the bluff body's pulsation leads to alteration of the omnipresent Krmn vortices and the possibility of optimizing the lift-to-drag ratio as well as the rates of heat and mass transfer. Other useful applications include the ability to enhance or suppress the turbulence intensity, and to avoid the potentially destructive lock-in phenomenon in the wake of bridges, electric cables and other structures.

  5. Buoyancy-driven flow reversal phenomena in radially rotating serpentine ducts

    SciTech Connect

    Hwang, J.J.; Wang, W.J.; Chen, C.K.

    2000-02-01

    Convective characteristics are analyzed numerically in a rotating multipass square duct connecting with 180-deg sharp returns. Isoflux is applied to each duct wall and periodic conditions are used between the entrance and exit of a typical two-pass module. Emphasis is placed on the phenomenon of buoyancy-driven reversed flow in the serpentine duct. Predictions reveal that the radial distance from the rotational axis to the location of flow separation in the radial-outward duct decreases with increasing the Richardson number. In addition, the local buoyancy that is required to yield the radial flow reversal increases with increasing the rotation number. This buoyancy-driven reversed flow in the radial-outward duct always results in local hot spots in the cooling channels. The critical buoyancy for the initiation of flow reversal is therefore concluded for the design purpose.

  6. Detailed kinetic performance analysis of micromachined radially elongated pillar array columns for liquid chromatography.

    PubMed

    Callewaert, Manly; Desmet, Gert; Ottevaere, Heidi; De Malsche, Wim

    2016-02-12

    The individual factors that determine the kinetic performance (B- and C-term band broadening and bed permeability Kv) of radially elongated pillar (REP) columns are studied. To this end, columns with REPs having 4 different aspect ratios (AR=9, 12, 15, 20) were characterized experimentally and by means of numerical simulations. A tortuosity and retention based plate height equation was established, enabling a good global fit for all studied conditions. The B-term plate height contribution appears to decrease with a factor equaling the square of the flow path tortuosity τ. Going from AR=12 to AR=20 (τ=5.7 and τ=9.0 respectively), this resulted in a shift in plate height expressed in axial coordinates from Hmin=0.42μm to Hmin=0.25 for non-retained conditions and from H=0.77μm to H=0.57μm for a component with k=1.0. The obtained parameters were combined to predict optimal time-efficiency combinations for all possible channel lengths. This revealed an efficiency limit of N=10(7) plates for a non-retained component and N=7-8×10(6) for k=1 for a channel with an AR=20, corresponding to a channel length of 2.5m and a void time of 2.4h. PMID:26795281

  7. Numerical model of fluid flow and oxygen transport in a radial-flow microchannel containing hepatocytes.

    PubMed

    Ledezma, G A; Folch, A; Bhatia, S N; Balis, U J; Yarmush, M L; Toner, M

    1999-02-01

    The incorporation of monolayers of cultured hepatocytes into an extracorporeal perfusion system has become a promising approach for the development of a temporary bioartificial liver (BAL) support system. In this paper we present a numerical investigation of the oxygen tension, shear stress, and pressure drop in a bioreactor for a BAL composed of plasma-perfused chambers containing monolayers of porcine hepatocytes. The chambers consist of microfabricated parallel disks with center-to-edge radial flow. The oxygen uptake rate (OUR), measured in vitro for porcine hepatocytes, was curve-fitted using Michaelis-Menten kinetics for simulation of the oxygen concentration profile. The effect of different parameters that may influence the oxygen transport inside the chambers, such as the plasma flow rate, the chamber height, the initial oxygen tension in the perfused plasma, the OUR, and K(m) was investigated. We found that both the plasma flow rate and the initial oxygen tension may have an important effect upon oxygen transport. Increasing the flow rate and/or the inlet oxygen tension resulted in improved oxygen transport to cells in the radial-flow microchannels, and allowed significantly greater diameter reactor without oxygen limitation to the hepatocytes. In the range investigated in this paper (10 microns < H < 100 microns), and for a constant plasma flow rate, the chamber height, H, had a negligible effect on the oxygen transport to hepatocytes. On the contrary, it strongly affected the mechanical stress on the cells that is also crucial for the successful design of the BAL reactors. A twofold decrease in chamber height from 50 to 25 microns produced approximately a fivefold increase in maximal shear stress at the inlet of the reactor from 2 to 10 dyn/cm2. Further decrease in chamber height resulted in shear stress values that are physiologically unrealistic. Therefore, the channel height needs to be carefully chosen in a BAL design to avoid deleterious hydrodynamic effects on hepatocytes. PMID:10080090

  8. Capillary chromatography based on tube radial distribution of aqueous-organic mixture carrier solvents.

    PubMed

    Jinno, Naoya; Itano, Minoru; Hashimoto, Masahiko; Tsukagoshi, Kazuhiko

    2009-10-15

    A capillary chromatography system was developed using open capillary tubes made of fused-silica, polyethylene, or poly(tetrafluoroethylene), and an aqueous-organic mixture (water-acetonitrile-ethyl acetate mixture) as a carrier solution. Model analyte mixture solutions, such as 2,6-naphthalenedisulfonic acid and 1-naphthol, Eosin Y and perylene, bis[N,N-bis(carboxymethyl)aminomethyl]fluorescein and 1,1'-bi-2-naphthol, and 2,7-naphthalenedisulfonic acid and p-nitroaniline, were injected into the capillary tube by a gravity method. The analyte solutions were subsequently delivered through the capillary tube with the carrier solution by a micro-syringe pump. The system worked under laminar flow conditions. The analytes were separated through the capillary tube and detected on-capillary by an absorption detector. For example, 2,6-naphthalenedisulfonic acid and 1-naphthol were detected in this order with a carrier solution of water-acetonitrile-ethyl acetate (volume ratio 15:3:2), while they were detected in the reverse order with a carrier solution of water-acetonitrile-ethyl acetate (volume ratio 2:9:4). The other analyte solutions were similarly separated by the system. The elution times of the analytes could be easily reversed by changing the component ratio of the solvents in the carrier solution. PMID:19635369

  9. Standard Flow Liquid Chromatography for Shotgun Proteomics in Bioenergy Research

    PubMed Central

    Gonzlez Fernndez-Nio, Susana M.; Smith-Moritz, A. Michelle; Chan, Leanne Jade G.; Adams, Paul D.; Heazlewood, Joshua L.; Petzold, Christopher J.

    2015-01-01

    Over the past 10?years, the bioenergy field has realized significant achievements that have encouraged many follow on efforts centered on biosynthetic production of fuel-like compounds. Key to the success of these efforts has been transformational developments in feedstock characterization and metabolic engineering of biofuel-producing microbes. Lagging far behind these advancements are analytical methods to characterize and quantify systems of interest to the bioenergy field. In particular, the utilization of proteomics, while valuable for identifying novel enzymes and diagnosing problems associated with biofuel-producing microbes, is limited by a lack of robustness and limited throughput. Nano-flow liquid chromatography coupled to high-mass accuracy, high-resolution mass spectrometers has become the dominant approach for the analysis of complex proteomic samples, yet such assays still require dedicated experts for data acquisition, analysis, and instrument upkeep. The recent adoption of standard flow chromatography (ca. 0.5?mL/min) for targeted proteomics has highlighted the robust nature and increased throughput of this approach for sample analysis. Consequently, we assessed the applicability of standard flow liquid chromatography for shotgun proteomics using samples from Escherichia coli and Arabidopsis thaliana, organisms commonly used as model systems for lignocellulosic biofuels research. Employing 120?min gradients with standard flow chromatography, we were able to routinely identify nearly 800 proteins from E. coli samples; while for samples from Arabidopsis, over 1,000 proteins could be reliably identified. An examination of identified peptides indicated that the method was suitable for reproducible applications in shotgun proteomics. Standard flow liquid chromatography for shotgun proteomics provides a robust approach for the analysis of complex samples. To the best of our knowledge, this study represents the first attempt to validate the standard flow approach for shotgun proteomics. PMID:25883932

  10. On the Problem of Theoretical Pressure of a Radial-Flow Pump Unit

    NASA Astrophysics Data System (ADS)

    Pavlechko, V. N.; Protasov, S. K.

    2014-11-01

    An analysis has been made of the velocity of motion of a medium in the wheel of a radial-flow pump unit under the action of a centrifugal force and overcoming the medium's inertial force with its blades. Relations for the pressure produced by the radial-flow pump unit as a function of the angle of inclination of its blades have been derived. The well-known Euler equation describing the dynamic pressure of the radial-flow pump unit has been supplemented to determine its static pressure. An analysis of the obtained results has shown that the pressure of the radial-flow pump unit is maximum at an angle of inclination of its blades of 110o and negative at 140o or larger angles.

  11. Infant-specific gaze patterns to the focus of a radial optic flow.

    PubMed

    Shirai, Nobu; Imura, Tomoko

    2015-09-01

    The focus of a radial optic flow serves as a cue for perceiving direction of locomotion (e.g. Gibson, 1950). Niemann et al. (1999) reported that when naive adult observers passively viewed a radial flow, they tended to gaze around the focus of the radial flow. We examined whether the similar gaze behavior is observed in young infants (4-6 months, N = 20) in the present study. In each experimental trial (duration = 10 second), we presented either an expansion or a contraction flow (35.3 degree x 26.4 degree) composed of 500 moving dots on a computer screen as a visual stimulus. The focus of a radial flow horizontally moved back and forth (temporal frequency = 0.2 Hz) between the right and left side of the screen (distance = 18.4 degree). Infants' gaze behaviors were recorded by an eye tracker (Tobii X120) during each trial, and a circular area of interest (subtended 9.2 degree) was set at around the focus of a radial flow. Two mean flow-speed conditions (5.8 degree/s and 11.6 degree/s) were adopted, thus there were four experimental conditions (expansion/contraciton vs. low/high speeds). Two trials were done for each experimental condition, so that each infant took part in a total of 8 trials. The result showed that the infants looked significantly longer around the focus of a contraction than that of an expansion. No significant effect of flow speed was observed. Additionally, our pilot study indicated naive adults looked significantly longer at the focus of an expansion than that of a contraction. These results suggest that gaze behaviors to radial optic flows are substantially different between adults and infants aged around 5 months, while similarly aged infants have fundamental abilities to detect the focus of a radial flow (e.g. Gilmore et al., 2004). Meeting abstract presented at VSS 2015. PMID:26326487

  12. MODFLOW procedure to simulate axisymmetric flow in radially heterogeneous and layered aquifer systems

    NASA Astrophysics Data System (ADS)

    Louwyck, Andy; Vandenbohede, Alexander; Bakker, Mark; Lebbe, Luc

    2014-08-01

    A procedure is outlined to simulate axisymmetric groundwater flow in radially heterogeneous and layered aquifer systems using the unmodified version of MODFLOW. The procedure is straightforward, as it only requires correction of some of the input parameters. In contrast to other MODFLOW procedures to simulate axisymmetric flow, no restrictions are imposed on the type of flow, the discretization of radial distance, or the parameter values. Hence, the method can deal with both confined and unconfined flow, wellbore storage, and axisymmetric aquifer inhomogeneities including effects of finite-thickness skin and gravel pack. Several test cases are presented, which compare the calculated results with existing analytical solutions, the analytic element solver TTim, and the axisymmetric, finite-difference model MAxSym. It is concluded that the MODFLOW procedure is capable of simulating accurately axisymmetric flow in radially heterogeneous multi-aquifer systems.

  13. Parameter Estimation of Transmissivity Fields with Non-radial Flow Dimensions

    NASA Astrophysics Data System (ADS)

    Bowman, D. O.; Roberts, R. M.; Holt, R. M.

    2008-12-01

    Non-radial flow signatures are seen in many hydraulic tests in fractured media. The generalized radial flow approach, which uses a variable flow dimension (n) to incorporate changing cross-sectional area of flow, is increasingly used to account for non-radial flow in hydraulic test interpretation. Representing non-radial flow in a 2-D numerical model has been problematic. As part of an effort to understand the structuring of heterogeneous transmissivity that produces persisting non-radial flow dimensions, we generated spatially correlated binary random transmissivity fields. Simulated pumping in these fields produced delta pressures, log-derivatives, and flow dimensions similar to those observed in pumping tests conducted in fractured dolomite at the Waste Isolation Pilot Plant (WIPP) site. As the main point of interest for pumping tests is the estimation of aquifer parameters (i.e., storativity (S) and hydraulic conductivity (K)), we evaluate two methods of parameter estimation in our binary random fields: a variable geometry approach and a variable K approach. We examine error in aquifer parameter estimates for each method and characterize the sources of error. Our methods may provide insight into how to better understand and apply parameter estimation techniques in similar flow systems and reveal possible pitfalls that exist in assuming radial flow geometries. Acknowledgements This research is funded by WIPP programs administered by the Office of Environmental Management (EM) of the U.S. Department of Energy. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  14. Stability of the Taylor-Couette flow under a radial thermoelectric body force

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Harunori; Mutabazi, Innocent; Crumeyrolle, Olivier; Meyer, Antoine

    2013-11-01

    A circular Couette flow developed between coaxial two infinite-length cylinders is considered in the case where only the inner cylinder is rotating. A radial temperature gradient and a radial electric field are applied to the flow, their coupling resulting in the dielectrophoretic body force density. This thermoelectric force can stabilize and destabilize the flow, depending on the heating direction. The critical Taylor number, wavenumber and frequency are determined for a wide range of control parameters. The mechanism behind the instability will be discussed. This work benefited from a financial support from CNES (French Space Agency), the CPER-Haute Normandie under the program THETE and from the FEDER.

  15. Transient radial flow to a well in an unconfined aquifer

    SciTech Connect

    Narasimhan, T.N.; Zhu, Ming.

    1991-08-01

    The analytic solutions of Boulton (1954) and Neuman (1972) for transient flow to a well in an unconfined aquifer are based on the assumption that the role of the unsaturated zone can be adequately accounted for by restricting attention to the release of water from the zone through which the water table moves. Both researchers mathematically treat this released water as a time-dependent source term. The differences between the models of Boulton and Neuman are that the former neglects vertical components of flow in the aquifer, but allows for an exponential process for the release of water as a function of time, whereas the latter assumes instantaneous release from storage, but accounts for vertical components of flow. Given this set of assumptions, we examine the applicability of these two methods using a general purpose numerical model through a process of verification extension and comparison. The issues addressed include: the role of well-bore storage in masking intermediate-time behavior, combined effects of exponential release as well as vertical flow, logic for vertical averaging of drawdowns, and the sensitivity of system response to the magnitude of specific yield. The issue of how good the assumptions of Boulton and Neuman are in the context of the general theory of unsaturated flow is addressed in part 2 of this two-part series of reports.

  16. Radial flow towards well in leaky unconfined aquifer

    NASA Astrophysics Data System (ADS)

    Mishra, P. K.; Kuhlman, K. L.

    2012-12-01

    An analytical solution is developed for three-dimensional flow towards a partially penetrating large- diameter well in an unconfined aquifer bounded below by a leaky aquitard of finite or semi-infinite extent. The analytical solution is derived using Laplace and Hankel transforms, then inverted numerically. Existing solutions for flow in leaky unconfined aquifers neglect the unsaturated zone following an assumption of instantaneous drainage due to Neuman. We extend the theory of leakage in unconfined aquifers by (1) including water flow and storage in the unsaturated zone above the water table, and (2) allowing the finite-diameter pumping well to partially penetrate the aquifer. The investigation of model-predicted results shows that aquitard leakage leads to significant departure from the unconfined solution without leakage. The investigation of dimensionless time-drawdown relationships shows that the aquitard drawdown also depends on unsaturated zone properties and the pumping-well wellbore storage effects.

  17. Three Phase Probabilistic Load Flow in Radial Distribution Networks

    SciTech Connect

    Melhorn, Alexander C; Dimitrovski, Aleksandar D; Tomsovic, Kevin L

    2012-01-01

    Probabilistic load flow is a helpful tool in accounting for inconsistent or unknown loads and generation. This is especially true with the push for renewable generation and demand response. This paper proposes an improved version of the probabilistic load flow solution for balanced distribution systems and takes the next step by applying it to unbalanced three phase systems. It is validated by comparing the solutions to that obtained by Monte Carlo simulation. The proposed method provides an accurate and practical way for finding the solution to the stochastic problems occurring in power distribution system analysis today.

  18. Flow behavior in inlet guide vanes of radial turbines

    NASA Technical Reports Server (NTRS)

    Sokhey, J.; Tabakoff, W.; Hosny, W. M.

    1975-01-01

    Scroll flow is discussed. Streamline pattern and velocity distribution in the guide vanes are calculated. The blade surface temperature distribution is also determined. The effects of the blade shapes and the nozzle channel width on the velocity profiles at inlet to the guide vanes are investigated.

  19. Preprocessor and postprocessor computer programs for a radial-flow finite-element model

    USGS Publications Warehouse

    Pucci, A.A., Jr.; Pope, D.A.

    1987-01-01

    Preprocessing and postprocessing computer programs that enhance the utility of the U.S. Geological Survey radial-flow model have been developed. The preprocessor program: (1) generates a triangular finite element mesh from minimal data input, (2) produces graphical displays and tabulations of data for the mesh , and (3) prepares an input data file to use with the radial-flow model. The postprocessor program is a version of the radial-flow model, which was modified to (1) produce graphical output for simulation and field results, (2) generate a statistic for comparing the simulation results with observed data, and (3) allow hydrologic properties to vary in the simulated region. Examples of the use of the processor programs for a hypothetical aquifer test are presented. Instructions for the data files, format instructions, and a listing of the preprocessor and postprocessor source codes are given in the appendixes. (Author 's abstract)

  20. Chromatography.

    ERIC Educational Resources Information Center

    Brantley, L. Reed, Sr.; Demanche, Edna L.; Klemm, E. Barbara; Kyselka, Will; Phillips, Edwin A.; Pottenger, Francis M.; Yamamoto, Karen N.; Young, Donald B.

    This booklet presents some activities on chromatography. Directions for preparing leaf pigment extracts using alcohol are given, and paper chromatography and thin-layer chromatography are described as modifications of the basic principles of chromatography. (KHR)

  1. Anomalous magnetosheath flows and distorted subsolar magnetopause for radial interplanetary magnetic fields

    NASA Astrophysics Data System (ADS)

    Shue, J.-H.; Chao, J.-K.; Song, P.; McFadden, J. P.; Suvorova, A.; Angelopoulos, V.; Glassmeier, K. H.; Plaschke, F.

    2009-09-01

    On 12 August 2007 from 1436 to 1441 UT, when the five THEMIS probes (THA, THB, THC, THD, and THE) were located near the subsolar magnetopause, a sunward flow was observed in the magnetosheath. A fast anti-sunward flow (-280 km/s) was observed in the magnetosheath before the sunward flow. Although THA observed this fast anti-sunward flow, THC and THD, which were also in the magnetosheath, instead observed a slow flow, indicating that the fast flow was small in scale. With the observed flow vectors and the magnetopause normal directions estimated from tangential discontinuity analysis, we conclude that this fast flow creates an indentation on the magnetopause, 1 R E deep and 2 R E wide. The magnetopause subsequently rebounds, rotating the flow direction sunward along the surface of the magnetopause. The fast flow is likely related to the radial interplanetary magnetic field.

  2. Anomalous Magnetosheath Flows and Distorted Subsolar Magnetopause for Radial Interplanetary Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Shue, J.; Chao, J. K.; Song, P.; McFadden, J. P.; Suvorova, A.; Angelopoulos, V.; Glassmeier, K.; Plaschke, F.

    2009-12-01

    On 12 August 2007 from 1436 to 1441 UT, when the five THEMIS probes (THA, THB, THC, THD, and THE) were located near the subsolar magnetopause, a sunward flow was observed in the magnetosheath. A fast anti-sunward flow (-280 km/s) was observed in the magnetosheath before the sunward flow. Although THA observed this fast anti-sunward flow, THC and THD, which were also in the magnetosheath, instead observed a slow flow, indicating that the fast flow was small in scale. With the observed flow vectors and the magnetopause normal directions estimated from tangential discontinuity analysis, we conclude that this fast flow creates an indentation on the magnetopause, 1 Re deep and 2 Re wide. The magnetopause subsequently rebounds, rotating the flow direction sunward along the surface of the magnetopause. The fast flow is likely related to the radial interplanetary magnetic field.

  3. Travel time statistics under radially converging flow in single fractures

    NASA Astrophysics Data System (ADS)

    Gotovac, Hrvoje; Srzic, Veljko; Cvetkovic, Vladimir; Kekez, Toni; Malenica, Luka

    2015-04-01

    A stochastic methodology based on Adaptive Fup Monte Carlo Method is used to investigate transport of a conservative solute by steady flow to a single pumping well in two-dimensional randomly heterogeneous single fractures. The spatially variable hydraulic transmissivity is modeled as a stationary random function for three different correlation structures (multi-Gaussian, connected and disconnected fields with correlated mean, high and low lnT values, respectively, according to the Zinn and Harvey, 2003) and heterogeneity levels (lnT variance is 1 and 8). Initially, solute particles are injected at outer circle located at 32 correlation lengths from well according to the in flux and resident injection mode. Therefore, breakthrough curve (BTC) statistics in single well due to different spatial structures, heterogeneity levels, injection modes and dispersion influence is considered. For small heterogeneity, all considered effects have small influences on BTC and related moments. As expected in single fractures, high lnT variance is more usual case which considerably changes flow patterns including channelling effect and fact that only few narrow channels carry out most pumping flow rate. Channelling implies significant differences between different injection modes. Resident mode uniformly injects particles implying that most particles pass through "slower" zones that especially increase late arrivals and contribute to the non-Fickian behaviour of transport. Contrary, "in flux" mode drastically reduces first arrivals and mean values, especially for connected correlation fields. The results from two injection modes lie on different sides of homogeneous mean travel time solution and give complementary information for complete representation of conservative transport. For advection transport, correlation structure and especially lnT variance seems to have major influence on BTC characteristics. On the other side, influence of longitudinal and lateral local scale dispersion are negligible, especially for resident injection mode.

  4. Three-dimensional flow measurements in a vaneless radial turbine scroll

    NASA Technical Reports Server (NTRS)

    Tabakoff, W.; Wood, B.; Vittal, B. V. R.

    1982-01-01

    The flow behavior in a vaneless radial turbine scroll was examined experimentally. The data was obtained using the slant sensor technique of hot film anemometry. This method used the unsymmetric heat transfer characteristics of a constant temperature hot film sensor to detect the flow direction and magnitude. This was achieved by obtaining a velocity vector measurement at three sensor positions with respect to the flow. The true magnitude and direction of the velocity vector was then found using these values and a Newton-Raphson numerical technique. The through flow and secondary flow velocity components are measured at various points in three scroll sections.

  5. EXPERIMENTAL CHARACTERIZATION OF COHERENT, RADIALLY-SHEARED ZONAL FLOWS IN THE DIII-D TOKAMAK

    SciTech Connect

    MCKEE,GR; FONCK,RJ; JAKUBOWSKI,M; BURRELL,KH; HALLATSCHEK,K; MOYER,RA; NEVINS,W; PORTER,GD; RUDAKOV,DL; XU,X

    2002-11-01

    A271 EXPERIMENTAL CHARACTERIZATION OF COHERENT, RADIALLY-SHEARED ZONAL FLOWS IN THE DIII-D TOKAMAK. Application of time-delay-estimation techniques to two-dimensional measurements of density fluctuations, obtained with beam emission spectroscopy in DIII-D plasmas, has provided temporally and spatially resolved measurements of the turbulence flow-field. Features that are characteristic of self-generated zonal flows are observed in the radial region near 0.85 {<=} r/a {<=} 1.0. These features include a coherent oscillation (approximately 15 kHz) in the poloidal flow of density fluctuations that has a long poloidal wavelength, possibly m = 0, narrow radial extent (k{sub r}{rho}{sub I} < 0.2), and whose frequency varies monotonically with the local temperature. The approximate effective shearing rate, dv{sub {theta}}/dr, of the flow is of the same order of magnitude as the measured nonlinear decorrelation rate of the turbulence, and the density fluctuation amplitude is modulated at the frequency of the observed flow oscillation. Some phase coherence is observed between the higher wavenumber density fluctuations and low frequency poloidal flow fluctuations, suggesting a Reynolds stress contribution. These characteristics are consistent with predicted features of zonal flows, specifically identified as geodesic acoustic modes, observed in 3-D Braginskii simulations of core/edge turbulence.

  6. Three dimensional unsteady flow calculations in radial components

    NASA Astrophysics Data System (ADS)

    Fatsis, A.

    A numerical model to predict the impeller response due to the downstream static pressure distortion caused by the volute when a centrifugal compressor works at off design conditions is presented. The three dimensional Euler equations are solved by a time marching technique allowing the evaluation of the unsteady flowfield using the finite volume space discretization and Runge-Kutta time stepping scheme. Phase lagged periodicity conditions were used in the computations of the unsteady flow upstream and downstream the blade channel. Reflecting and non-reflecting boundary conditions were tested. It was demonstrated that the latter result in faster convergence than the former. A cyclic variation of the impeller flowfield due to the donwstream static pressure non-uniform distribution is observed.

  7. Poloidal Ion Flow Modification and Reduction of Radial Particle Transport in PISCES-A

    NASA Astrophysics Data System (ADS)

    Lehmer, R. D.; Schmitz, L.; Conn, R. W.

    1996-11-01

    Increases in the sheared edge electric field and poloidal ion flow have been observed to coincide with the L to H transition and the formation of a radial transport barrier in tokamaks. Experiments in the PISCES-A linear reflex arc discharge device study the effect of the radial electric field on the plasma turbulence and the fluctuation-induced radial particle transport. When the electric field layer width is on the order of the ion Larmor radius (lE ? 1-2 ?_i), the poloidal ion flow induced by the electric field profile is significantly modified from the E B drift speed. Under these conditions, the poloidal ion rotation increases as the electric field layer width increases. A radial transport barrier forms if the magnitude of the poloidal ion rotation is substantially increased by widening the electric field layer. Modeling of the poloidal ion flow profile is consistent with the experimental measurement of the phase velocity of coherent structures. Detailed, two-dimensional measurements of the spatial size and radial and poloidal propagation of coherent structures observed in the plasma will also be presented. Work supported by US-DOE contract DE-FG03-95ER-54301.

  8. Radial heterogeneity of some analytical columns used in high-performance liquid chromatography

    SciTech Connect

    Mriziq, Khaled S; Guiochon, Georges A

    2009-01-01

    An on-column electrochemical microdetector was used to determine accurately the radial distribution of the mobile phase velocity and of the column efficiency at the exit of three common analytical columns, namely a 100 mm x 4.6 mm C18 bonded silica-based monolithic column, a 150 mm x 4.6 mm column packed with 2.7 {micro}m porous shell particles of C18 bonded silica (HALO), and a 150 mm x 4.6 mm column packed with 3 {micro}m fully porous C18 bonded silica particles (LUNA). The results obtained demonstrate that all three columns are not radially homogeneous. In all three cases, the efficiency was found to be lower in the wall region of the column than in its core region (the central core with a radius of 1/3 the column inner radius). The decrease in local efficiency from the core to the wall regions was lower in the case of the monolith (ca. 25%) than in that of the two particle-packed columns (ca. 35-50%). The mobile phase velocity was found to be ca. 1.5% higher in the wall than in the core region of the monolithic column while, in contrast, it was ca. 2.5-4.0% lower in the wall region for the two particle-packed columns.

  9. Liquid chromatography/Fourier transform IR spectrometry interface flow cell

    DOEpatents

    Johnson, Charles C.; Taylor, Larry T.

    1986-01-01

    A zero dead volume (ZDV) microbore high performance liquid chromatography (.mu.HPLC)/Fourier transform infrared (FTIR) interface flow cell includes an IR transparent crystal having a small diameter bore therein through which a sample liquid is passed. The interface flow cell further includes a metal holder in combination with a pair of inner, compressible seals for directly coupling the thus configured spectrometric flow cell to the outlet of a .mu.HPLC column end fitting to minimize the transfer volume of the effluents exiting the .mu.HPLC column which exhibit excellent flow characteristics due to the essentially unencumbered, open-flow design. The IR beam passes transverse to the sample flow through the circular bore within the IR transparent crystal, which is preferably comprised of potassium bromide (KBr) or calcium fluoride (CaF.sub.2), so as to minimize interference patterns and vignetting encountered in conventional parallel-plate IR cells. The long IR beam pathlength and lensing effect of the circular cross-section of the sample volume in combination with the refractive index differences between the solvent and the transparent crystal serve to focus the IR beam in enhancing sample detection sensitivity by an order of magnitude.

  10. Liquid chromatography/Fourier transform IR spectrometry interface flow cell

    DOEpatents

    Johnson, C.C.; Taylor, L.T.

    1985-01-04

    A zero dead volume (ZDV) microbore high performance liquid chromatography (..mu.. HPLC)/Fourier transform infrared (FTIR) interface flow cell includes an IR transparent crystal having a small diameter bore therein through which a sample liquid is passed. The interface flow cell further includes a metal holder in combination with a pair of inner, compressible seals for directly coupling the thus configured spectrometric flow cell to the outlet of a ..mu.. HPLC column end fitting to minimize the transfer volume of the effluents exiting the ..mu.. HPLC column which exhibit excellent flow characteristics due to the essentially unencumbered, open-flow design. The IR beam passes transverse to the sample flow through the circular bore within the IR transparent crystal, which is preferably comprised of potassium bromide (KBr) or calcium fluoride (CaF/sub 2/), so as to minimize interference patterns and vignetting encountered in conventional parallel-plate IR cells. The long IR beam pathlength and lensing effect of the circular cross-section of the sample volume in combination with the refractive index differences between the solvent and the transparent crystal serve to focus the IR beam in enhancing sample detection sensitivity by an order of magnitude.

  11. Modelling of turbulent flow in a radial reactor with fixed bed

    NASA Astrophysics Data System (ADS)

    Zhapbasbayev, U. K.; Ramazanova, G. I.; Kenzhaliev, O. B.

    2015-03-01

    The data of the computation of turbulent flow in the CF- ? and CP- ? configurations of the radial reactor with a fixed bed are presented. The Reynolds motion equations have been solved jointly with the k- ? turbulence model. To couple the parameters of flows at the interface free part-fixed bed the classical continuity equations were used. The computational data are obtained for the averaged and turbulent characteristics, and it is shown that the flow in the fixed bed causes the generation of the turbulence kinetic energy and its dissipation rate; the flow in the CF- ? configuration is distributed more uniformly as compared to the CP- ? configuration of the radial reactor. Computed data are compared with the experimental ones.

  12. Radial Flow Fludized Filter Finds Niche as a Pretreatment System for Surface Water in Small Communities

    EPA Science Inventory

    An emerging technology called radial flow fluidized filter (R3f) has been developed as a low cost simplistic filtration technology for small communities of less than 10,000 people. Fouling is a major impediment to the sustainability of membrane technology particularly for small ...

  13. Solids removal from a coldwater recirculating system - comparison of swirl separator and radial-flow settlers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Solids removal across two settling devices, i.e., a swirl separator and a radial-flow settler, and across a microscreen drum filter was evaluated in a fully recirculating system containing a single 150 m3 'Cornell-type' dual-drain tank during the production of food-size Arctic char and rainbow trout...

  14. Designing and updating the flow part of axial and radial-axial turbines through mathematical modeling

    NASA Astrophysics Data System (ADS)

    Rusanov, Andrey; Rusanov, Roman; Lampart, Piotr

    2015-10-01

    The paper describes an algorithm for the design of axial and radial-axial type turbines. The algorithm is based on using mathematical models of various levels of complexity - from 1D to 3D. Flow path geometry is described by means of analytical methods of profiling using a limited number of parameters. 3D turbulent flow model is realised in the program complex IPMFlow, developed based on the earlier codes FlowER and FlowER-U. Examples of developed or modernized turbines for differentpurpose power machines are presented. They are: an expansion turbine, ORC turbine and cogeneration mediumpressure turbine.

  15. Viscous potential flow analysis of radial fingering in a Hele-Shaw cell

    NASA Astrophysics Data System (ADS)

    Kim, Hyungjun; Funada, Toshio; Joseph, Daniel D.; Homsy, G. M.

    2009-07-01

    The problem of radial fingering in two phase gas/liquid flow in a Hele-Shaw cell under injection of gas is studied here. The fingers arise as an instability of a time-dependent flow. The instability is analyzed as a viscous potential flow, in which potential flow analysis of Paterson [L. Paterson, J. Fluid Mech. 113, 513 (1981)] and others is augmented to account for the effects of viscosity on the normal stress at the gas/liquid interface. The addition of these new effects brings our theory into a much better agreement with experiments of Maxworthy [T. Maxworthy, Phys. Rev. A 39, 5863 (1989)] than other theories.

  16. Response of a radial-bladed centrifugal pump to sinusoidal disturbances for noncavitating flow

    NASA Technical Reports Server (NTRS)

    Anderson, D. A.; Blade, R. J.; Stevans, W.

    1971-01-01

    A radial-bladed centrifugal pump was run in water with sinusoidal fluctuations of pressure and flow rate imposed at the pump inlet. Since the flow was noncavitating, zero gain was assumed in computing pump impedance. The inertive reactance became greater than the resistance at relatively low frequencies. An electric circuit model was developed in order to explain the trends of inertance and resistance with frequency.

  17. Secondary Floquet modes of instability in Taylor-Couette flow with axial and radial through-flows

    NASA Astrophysics Data System (ADS)

    Martinand, Denis; Serre, Eric; Lueptow, Richard

    2013-11-01

    Injecting a fluid between a fixed outer impermeable cylinder and concentric rotating permeable inner one and driving it axially is a set-up used in some filtration devices or enzymatic reactors, where the rotation of the inner cylinder promotes mixing or prevents accumulation processes. This set-up can be seen as a Taylor-Couette flow with superimposed axial and radial through-flows and a precise knowledge of the flow structures at stake is a prerequisite for improving these devices. We address the instabilities observed after the laminar flow of a pure, Newtonian solvent has undergone its first two transitions. Previous linear stability analysis has shown that critical convective instabilities take the form of travelling toroidal vortices, turning to helical vortices as the axial flow is increased. Moreover, a weakly non-linear analysis have shown that this primary transition can be subcritical as the radial flow is increased. Based on these previous results, the stability of these primary modes is studied by Floquet analysis. Depending on the strength of the axial and radial flows, harmonic or subharmonic secondary modes are found to be the most dangerous ones. The analytical results are compared to direct numerical simulations using a pseudo-spectral method.

  18. Measurement and Modeling of the Flows and Radial Electric Field in the HSX Stellarator

    NASA Astrophysics Data System (ADS)

    Briesemeister, Alexis R.

    A charge exchange recombination spectroscopy (CHERS) diagnostic was developed and used to measure the C+6 velocity, temperature and density in the HSX stellarator. These measurements were used to determine the radial electric field (Er) and parallel flow velocities which were compared to neoclassical calculations. Neoclassical calculations of E r and parallel flow velocities in stellarators are typically performed using a simplified non-momentum conserving collision operator, but these calculations were found to under predict the parallel flow velocity in HSX by approximately an order of magnitude. The inclusion of momentum conservation in the PENTA code improved the agreement between the measured and calculated total plasma flow direction, which approximately follows the helical direction of symmetry in HSX. However, discrepancies were seen between the measured and calculated Er and parallel flow profiles. In the core, the parallel flows were measured to reach speeds of up to 20 km/s in the optimized quasi-helically symmetric (QHS) magnetic configuration, but these measured values were slower than the values calculated by PENTA in that region. For the Mirror magnetic configuration, in which the symmetry of the magnetic field is intentionally broken, the calculated parallel flow was smaller than the flow calculated for the QHS configuration but was still larger than the measured flow. The measured radial electric field was about 2 kV/m across the plasma. The radial electric field calculations had multiple solutions, or roots, in the core of HSX plasmas. The measured Er was found to be much lower than the large, 30 kV/m, electron root value which was calculated by PENTA. Better agreement was seen between the measured Er and the smaller ion root value calculated for much of the plasma. No measureable change in the parallel flow was seen when the plasma density was varied within the operationally achievable range. A significant increase in the measured parallel flow was seen with increased electron heating.

  19. Three-dimensional inviscid analysis of radial turbine flow and a limited comparison with experimental data

    NASA Technical Reports Server (NTRS)

    Choo, Y. K.; Civinskas, K. C.

    1985-01-01

    The three-dimensional inviscid DENTON code is used to analyze flow through a radial-inflow turbine rotor. Experimental data from the rotor are compared with analytical results obtained by using the code. The experimental data available for comparison are the radial distributions of circumferentially averaged values of absolute flow angle and total pressure downstream of the rotor exit. The computed rotor-exit flow angles are generally underturned relative to the experimental values, which reflect the boundary-layer separation at the trailing edge and the development of wakes downstream of the rotor. The experimental rotor is designed for a higher-than-optimum work factor of 1.126 resulting in a nonoptimum positive incidence and causing a region of rapid flow adjustment and large velocity gradients. For this experimental rotor, the computed radial distribution of rotor-exit to turbine-inlet total pressure ratios are underpredicted due to the errors in the finite-difference approximations in the regions of rapid flow adjustment, and due to using the relatively coarser grids in the middle of the blade region where the flow passage is highly three-dimensional. Additional results obtained from the three-dimensional inviscid computation are also presented, but without comparison due to the lack of experimental data. These include quasi-secondary velocity vectors on cross-channel surfaces, velocity components on the meridional and blade-to-blade surfaces, and blade surface loading diagrams. Computed results show the evolution of a passage vortex and large streamline deviations from the computational streamwise grid lines. Experience gained from applying the code to a radial turbine geometry is also discussed.

  20. A model of unsteady spatially inhomogeneous flow in a radial-axial blade machine

    NASA Astrophysics Data System (ADS)

    Ambrozhevich, A. V.; Munshtukov, D. A.

    A two-dimensional model of the gasdynamic process in a radial-axial blade machine is proposed which allows for the instantaneous local state of the field of flow parameters, changes in the set angles along the median profile line, profile losses, and centrifugal and Coriolis forces. The model also allows for the injection of cooling air and completion of fuel combustion in the flow. The model is equally applicable to turbines and compressors. The use of the method of singularities provides for a unified and relatively simple description of various factors affecting the flow and, therefore, for computational efficiency.

  1. L.D.V. measurements of unsteady flow fields in radial turbine

    NASA Astrophysics Data System (ADS)

    Tabakoff, W.; Pasin, M.

    1992-07-01

    Detailed measurements of an unsteady flow field within the inlet guide vanes (IGV) and the rotor of a radial inflow turbine were performed using a three component Laser Doppler Velocimeter (LDV) system together with a rotary encoder. The mean velocity, the flow angle and the turbulence contours for IGV passages are presented at four blade-to-blade planes for different rotor positions to give three dimensional, unsteady behavior of the IGV flow field. These results are compared with the measurements obtained in the same passage in the absence of the rotor. The flow field of the IGV passage was found to be affected by the presence of the rotor. The ratio of the tangential normal stresses to the radial normal stresses at the exit of the IGV was found to be more than doubled when compared to the case without the rotor. The rotor flow field measurements are presented as relative mean velocity and turbulence stress contours at various cross section planes throughout the rotor. The cross flow and turbulence stress levels were found to be influenced by the incidence angle. Transportation of the high turbulence fluid by the cross flow was observed downstream in the rotor blade passages.

  2. Stability analysis of a two-phase suspension between rotating porous cylinder with the radial flow

    NASA Astrophysics Data System (ADS)

    Wang, Feng-Hui; Zhu, Yu-Chuan; Wan, Zhan-Hong; He, Song

    2015-02-01

    The hydrodynamic stability analysis of viscous flow between rotating porous cylinder has been researched for a long time by many researchers. But little works have been carried out about the linear stability analysis of the two-phase suspension. When the radial flow is present, the linear hydrodynamic stability analysis of suspension has been carried out between rotating porous cylinder. We know that the continuous and Stokes equations cannot only solve the stability problem of the continuous fluid phase, but also solving the stability problem of the discontinuous particle phase. The stability equations from an eigenvalue problem that was solved by a numerical technique based on Wan's method. The results reveal that the radial Reynolds number have a great effect on the critical Taylor number in the suspension. In this paper, we also researched on how the critical Taylor number changes as the radius ratio ?, the axial wave number k, the particle concentration and the circumferential direction wave number happen to change with the radial Reynolds number increasing range from -5 to 5. Thus, our research discovered the radial inflow and outflow have a stabilizing effect on the two-phase suspension and the circumferential direction wave number also has a stabilizing effect.

  3. Porcine Circovirus (PCV) Removal by Q Sepharose Fast Flow Chromatography

    PubMed Central

    Yang, Bin; Wang, Hua; Ho, Cintia; Lester, Philip; Chen, Qi; Neske, Florian; Baylis, Sally A; Blmel, Johannes

    2013-01-01

    The recently discovered contamination of oral rotavirus vaccines led to exposure of millions of infants to porcine circovirus (PCV). PCV was not detected by conventional virus screening tests. Regulatory agencies expect exclusion of adventitious viruses from biological products. Therefore, methods for inactivation/removal of viruses have to be implemented as an additional safety barrier whenever feasible. However, inactivation or removal of PCV is difficult. PCV is highly resistant to widely used physicochemical inactivation procedures. Circoviruses such as PCV are the smallest viruses known and are not expected to be effectively removed by currently-used virus filters due to the small size of the circovirus particles. Anion exchange chromatography such as Q Sepharose Fast Flow (QSFF) has been shown to effectively remove a range of viruses including parvoviruses. In this study, we investigated PCV1 removal by virus filtration and by QSFF chromatography. As expected, PCV1 could not be effectively removed by virus filtration. However, PCV1 could be effectively removed by QSFF as used during the purification of monoclonal antibodies (mAbs) and a log10 reduction value (LRV) of 4.12 was obtained. 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:14641471, 2013 PMID:24039195

  4. Stability results for multi-layer radial Hele-Shaw and porous media flows

    NASA Astrophysics Data System (ADS)

    Gin, Craig; Daripa, Prabir

    2015-01-01

    Motivated by stability problems arising in the context of chemical enhanced oil recovery, we perform linear stability analysis of Hele-Shaw and porous media flows in radial geometry involving an arbitrary number of immiscible fluids. Key stability results obtained and their relevance to the stabilization of fingering instability are discussed. Some of the key results, among many others, are (i) absolute upper bounds on the growth rate in terms of the problem data; (ii) validation of these upper bound results against exact computation for the case of three-layer flows; (iii) stability enhancing injection policies; (iv) asymptotic limits that reduce these radial flow results to similar results for rectilinear flows; and (v) the stabilizing effect of curvature of the interfaces. Multi-layer radial flows have been found to have the following additional distinguishing features in comparison to rectilinear flows: (i) very long waves, some of which can be physically meaningful, are stable; and (ii) eigenvalues can be complex for some waves depending on the problem data, implying that the dispersion curves for one or more waves can contact each other. Similar to the rectilinear case, these results can be useful in providing insight into the interfacial instability transfer mechanism as the problem data are varied. Moreover, these can be useful in devising smart injection policies as well as controlling the complexity of the long-term dynamics when drops of various immiscible fluids intersperse among each other. As an application of the upper bound results, we provide stabilization criteria and design an almost stable multi-layer system by adding many layers of fluid with small positive jumps in viscosity in the direction of the basic flow.

  5. Enhanced mixing via alternating injection in radial Hele-Shaw flows

    NASA Astrophysics Data System (ADS)

    Chen, Ching-Yao; Huang, Yi-Cheng; Huang, Yu-Sheng; Miranda, Jos A.

    2015-10-01

    Mixing at low Reynolds numbers, especially in the framework of confined flows occurring in Hele-Shaw cells, porous media, and microfluidic devices, has attracted considerable attention lately. Under such circumstances, enhanced mixing is limited due to the lack of turbulence, and absence of sizable inertial effects. Recent studies, performed in rectangular Hele-Shaw cells, have demonstrated that the combined action of viscous fluid fingering and alternating injection can dramatically improve mixing efficiency. In this work, we revisit this important fluid mechanical problem, and analyze it in the context of radial Hele-Shaw flows. The development of radial fingering instabilities under alternating injection conditions is investigated by intensive numerical simulations. We focus on the impact of the relevant physical parameters of the problem (Pclet number Pe , viscosity contrast A , and injection time interval ? t ) on fluid mixing performance.

  6. [A new liver support system composed of functional human cells and a radial-flow bioreactor].

    PubMed

    Kawada, M; Nagamori, S; Aizaki, H; Fukaya, K; Niiya, M; Matsuura, T; Sujino, H; Hasumura, S; Shimizu, K; Yoshida, H

    1994-06-01

    An artificial liver will be useful for the treatment of acute hepatic failure and a bridge of liver transplantation. The current reports suggest that the hybrid type of artificial liver composed of functional human liver cells and a bioreactor is practical for clinical use. In the present study, we succeeded high density culture on a large-scale of human functional hepatoma (JHH-7) using a newly developed radial flow packed-bed bioreactor. Since the shear stress of this bioreactor is lower than the other type, high density culture without cell damage is possible. JHH-7 cells produced large amounts of human albumin and other liver specific proteins, and then have the function of ammonia metabolism in the system. This study suggests that a radial flow bioreactor will be developed as a new type of artificial liver. PMID:7524639

  7. Why is the radial flow in central pA collisions stronger than in AA?

    NASA Astrophysics Data System (ADS)

    Kalaydzhyan, Tigran; Shuryak, Edward

    2014-11-01

    Both the transverse size and entropy density per area in central pA collisions is smaller than in central AA, and yet the radial flow is stronger. We propose an explanation to this puzzle. Using a weak attraction between strings through the ?-meson exchange, fitted to the lattice data, we find collective implosion of the "spaghetti" multi-string state. Collectivization of the sigma field of the strings is the QCD analog of the black hole formation occurring in holographic models.

  8. Prediction of flow in a rotating cavity with radial outflow using a mixing length turbulence model

    NASA Astrophysics Data System (ADS)

    Chew, J. W.

    1985-07-01

    Numerical solutions of the elliptic equations for turbulent flow in the cavity formed between two rotating disks with a radial outflow of coolant are presented. The results are compared with experimental data, predictions from the K-e model, and an integral solution. It is concluded that the mixing length model can be used for engineering design calculations. The applications are limited by slow convergence of the iterative solution method at high rotational speeds.

  9. Occurrence of turbulent flow conditions in supercritical fluid chromatography.

    PubMed

    De Pauw, Ruben; Choikhet, Konstantin; Desmet, Gert; Broeckhoven, Ken

    2014-09-26

    Having similar densities as liquids but with viscosities up to 20 times lower (higher diffusion coefficients), supercritical CO2 is the ideal (co-)solvent for fast and/or highly efficient separations without mass-transfer limitations or excessive column pressure drops. Whereas in liquid chromatography the flow remains laminar in both the packed bed and tubing, except in extreme cases (e.g. in a 75 μm tubing, pure acetonitrile at 5 ml/min), a supercritical fluid can experience a transition from laminar to turbulent flow in more typical operation modes. Due to the significant lower viscosity, this transition for example already occurs at 1.3 ml/min for neat CO2 when using connection tubing with an ID of 127 μm. By calculating the Darcy friction factor, which can be plotted versus the Reynolds number in a so-called Moody chart, typically used in fluid dynamics, higher values are found for stainless steel than PEEK tubing, in agreement with their expected higher surface roughness. As a result turbulent effects are more pronounced when using stainless steel tubing. The higher than expected extra-column pressure drop limits the kinetic performance of supercritical fluid chromatography and complicates the optimization of tubing ID, which is based on a trade-off between extra-column band broadening and pressure drop. One of the most important practical consequences is the non-linear increase in extra-column pressure drop over the tubing downstream of the column which leads to an unexpected increase in average column pressure and mobile phase density, and thus decrease in retention. For close eluting components with a significantly different dependence of retention on density, the selectivity can significantly be affected by this increase in average pressure. In addition, the occurrence of turbulent flow is also observed in the detector cell and connection tubing. This results in a noise-increase by a factor of four when going from laminar to turbulent flow (e.g. going from 0.5 to 2.5 ml/min for neat CO2). PMID:25145564

  10. Optokinetic eye movements elicited by radial optic flow in the macaque monkey.

    PubMed

    Lappe, M; Pekel, M; Hoffmann, K P

    1998-03-01

    We recorded spontaneous eye movements elicited by radial optic flow in three macaque monkeys using the scleral search coil technique. Computer-generated stimuli simulated forward or backward motion of the monkey with respect to a number of small illuminated dots arranged on a virtual ground plane. We wanted to see whether optokinetic eye movements are induced by radial optic flow stimuli that simulate self-movement, quantify their parameters, and consider their effects on the processing of optic flow. A regular pattern of interchanging fast and slow eye movements with a frequency of 2 Hz was observed. When we shifted the horizontal position of the focus of expansion (FOE) during simulated forward motion (expansional optic flow), median horizontal eye position also shifted in the same direction but only by a smaller amount; for simulated backward motion (contractional optic flow), median eye position shifted in the opposite direction. We relate this to a change in Schlagfeld typically observed in optokinetic nystagmus. Direction and speed of slow phase eye movements were compared with the local flow field motion in gaze direction (the foveal flow). Eye movement direction matched well the foveal motion. Small systematic deviations could be attributed to an integration of the global motion pattern. Eye speed on average did not match foveal stimulus speed, as the median gain was only approximately 0.5-0.6. The gain was always lower for expanding than for contracting stimuli. We analyzed the time course of the eye movement immediately after each saccade. We found remarkable differences in the initial development of gain and directional following for expansion and contraction. For expansion, directional following and gain were initially poor and strongly influenced by the ongoing eye movement before the saccade. This was not the case for contraction. These differences also can be linked to properties of the optokinetic system. We conclude that optokinetic eye movements can be elicited by radial optic flow fields simulating self-motion. These eye movements are linked to the parafoveal flow field, i.e., the motion in the direction of gaze. In the retinal projection of the optic flow, such eye movements superimpose retinal slip. This results in complex retinal motion patterns, especially because the gain of the eye movement is small and variable. This observation has special relevance for mechanisms that determine self-motion from retinal flow fields. It is necessary to consider the influence of eye movements in optic flow analysis, but our results suggest that direction and speed of an eye movement should be treated differently. PMID:9497425

  11. Instability of the vertical annular flow with a radial heating and rotating inner cylinder

    NASA Astrophysics Data System (ADS)

    Yoshikawa, H. N.; Nagata, M.; Mutabazi, I.

    2013-11-01

    A linear stability analysis of the flow confined in a differentially rotating cylindrical annulus with a radial temperature gradient has been performed. Depending on values of control parameters (the Taylor number, the Grashof number, and the Froude number), it has shown flow destabilization to axisymmetric or non-axisymmetric modes. Analysis of different terms involved in the evolution rate of the perturbation kinetic energy has allowed us to isolate the dominant terms (centrifugal force or buoyancy force) in the destabilization process. We have shown that the centrifugal buoyancy can induce the asymmetry of the temperature gradient on critical states.

  12. Transport phenomena in radial flow MOCVD reactor with three concentric vertical inlets

    NASA Astrophysics Data System (ADS)

    Zuo, Ran; Zhang, Hong; Liu, Xiang-lin

    2006-08-01

    Transport phenomena in radial flow metalorganic chemical vapor deposition (MOCVD) reactor with three concentric vertical inlets are studied by two-dimensional numerical modeling. By varying the parameters such as gas pressure, flow rates combination of multi-inlets, geometric shapes and sizes of reactor and flow distributor, temperatures of susceptor and ceiling, and susceptor rotation, the corresponding velocity, temperature, and concentration fields inside the reactor are obtained; the onset and change of flow recirculation cells under influences of those parameters are determined. It is found that recirculation cells, originated from flow separation near the bend of reactor inlets, are affected mainly by the reactor height and shape, the operating pressure, the flow rates combination of multi-inlets, and the mean temperature between susceptor and ceiling. By increasing the flow rate of mid-inlet and the mean temperature, decreasing the pressure, maintaining the reactor height below certain criteria, and trimming the bends of reactor wall and flow distributor to streamlined shape, the recirculation cells can be minimized so that smooth and rectilinear flow prevails in the susceptor region, which corresponds to smooth and rectilinear isotherms and larger reactant concentration near the susceptor. For the optimized reactor shape, the reactor size can be enlarged to diameter D=40 cm and height H=2 cm without flow recirculation. The susceptor rotation over a few hundred rpm around the reactor central axis will induce the recirculation cell near the exit and deflect the streamlines near the susceptor, which is not the case for vertical reactors.

  13. Laser velocimeter measurements in shrouded and unshrouded radial flow pump impellers

    NASA Technical Reports Server (NTRS)

    Hamkins, C. P.; Flack, R. D.

    1986-01-01

    Shrouded and unshrouded versions of a four-vaned radial flow impeller with a design flow coefficient of 0.063 were tested in a volute pump using a two-component frequency-shifted laser velocimeter. Velocity profiles were measured at six flow rates and at four radial and six circumferential positions in the volute. The variations of the velocity from blade to blade and in the axial direction were measured and are presented. A passage vortex caused by tip leakage and relative casing wall velocity was found in the unshrouded impeller. The tip leakage did not accumulate in the suction wake region; the suction wake region was only 30 to 50 percent as large in the unshrouded impeller as compared to the shrouded impeller. The slip was 30 percent higher in the unshrouded impeller and the variation of slip with flow rate is presented. At no measured position in the impellers did the slip factor reach unity; the closest approach was 0.90. Reverse loadings of the vanes at outer radii were found for flow rates below the impeller/volute matching point for both impellers.

  14. Comparison of the flows and radial electric field in the HSX stellarator to neoclassical calculations

    NASA Astrophysics Data System (ADS)

    Briesemeister, A.; Zhai, K.; Anderson, D. T.; Anderson, F. S. B.; Talmadge, J. N.

    2013-01-01

    Intrinsic flow velocities of up to 20 km s-1 have been measured using charge exchange recombination spectroscopy (CHERS) in the quasi-helically symmetric HSX stellarator and are compared with the neoclassical values calculated using an updated version (Lore 2010 Measurement and Transport Modeling with Momentum Conservation of an Electron Internal Transport Barrier in HSX (Madison, WI: University of Wisconsin); Lore et al 2010 Phys. Plasmas 17 056101) of the PENTA code (Spong 2005 Phys. Plasmas. 12 056114). PENTA uses the monoenergetic transport coefficients calculated by the drift kinetic equation solver code (Hirshman et al 1986 Phys. Fluids 29 2951; van Rij and Hirshman 1989 Phys. Fluids B 1 563), but corrects for momentum conservation. In the outer half of the plasma good agreement is seen between the measured parallel flow profile and the calculated neoclassical values when momentum correction is included. The flow velocity in HSX is underpredicted by an order of magnitude when this momentum correction is not applied. The parallel flow is calculated to be approximately equal for the majority hydrogen ions and the C6+ ions used for the CHERS measurements. The pressure gradient of the protons is the primary drive of the calculated parallel flow for a significant portion of the outer half of the plasma. The values of the radial electric field calculated with and without momentum correction were similar, but both were smaller than the measured values in the outer half of the plasma. Differences between the measured and predicted radial electric field are possibly a result of uncertainty in the composition of the ion population and sensitivity of the ion flux calculation to resonances in the radial electric field.

  15. Chromatography

    MedlinePLUS

    Chromatography is a way of separating two or more chemical compounds. Chemical compounds are chemicals that are ... of chemical compound. There are different kinds of chromatography. These include gas, high pressure liquid, or ion ...

  16. An analysis of the viscous flow through a compact radial turbine by the average passage approach

    NASA Technical Reports Server (NTRS)

    Heidmann, James D.; Beach, Timothy A.

    1990-01-01

    A steady, three-dimensional viscous average passage computer code is used to analyze the flow through a compact radial turbine rotor. The code models the flow as spatially periodic from blade passage to blade passage. Results from the code using varying computational models are compared with each other and with experimental data. These results include blade surface velocities and pressures, exit vorticity and entropy contour plots, shroud pressures, and spanwise exit total temperature, total pressure, and swirl distributions. The three computational models used are inviscid, viscous with no blade clearance, and viscous with blade clearance. It is found that modeling viscous effects improves correlation with experimental data, while modeling hub and tip clearances further improves some comparisons. Experimental results such as a local maximum of exit swirl, reduced exit total pressures at the walls, and exit total temperature magnitudes are explained by interpretation of the flow physics and computed secondary flows. Trends in the computed blade loading diagrams are similarly explained.

  17. Radial distribution of the flow velocity, efficiency and concentration in a wide HPLC column

    SciTech Connect

    Farkas, T.; Sepaniak, M.J.; Guiochon, G.

    1997-08-01

    The use of optical fibers in a fluorescence-detection scheme permits the accurate determination of the radial distribution of the transit time, the column efficiency, and the analyte concentration at the exit of a chromatographic axial-compression column (50 mmID). The results obtained demonstrate that the column is not homogeneous, but suggest a nearly cylindrical distribution of the packing density. The average velocity close to the column wall is 7% lower than along its axis and the HETP 25% higher. The lack of homogeneity of the column packing is another source of band broadening not taken into account in chromatography so far. It causes the apparent HETP derived from the conventional elution chromatogram recorded on the bulk eluent to be larger than the local HETP and the band profile to be unsymmetrical with a slight tail reminiscent of kinetic tailing.

  18. On the nature of radial transport across sheared zonal flows in electrostatic ion-temperature-gradient gyrokinetic tokamak turbulence

    SciTech Connect

    Sanchez, Raul; Newman, David E; Leboeuf, Jean-Noel; Carreras, Benjamin A; Decyk, Viktor

    2009-01-01

    It is argued that the usual understanding of the suppression of radial turbulent transport across a sheared zonal flow based on a reduction in effective transport coefficients is, by itself, incomplete. By means of toroidal gyrokinetic simulations of electrostatic, ion-temperature-gradient turbulence, it is found instead that the character of the radial transport is altered fundamentally by the presence of a sheared zonal flow, changing from diffusive to anticorrelated and subdiffusive. Furthermore, if the flows are self-consistently driven by the turbulence via the Reynolds stresses (in contrast to being induced externally), radial transport becomes non-Gaussian as well. These results warrant a reevaluation of the traditional description of radial transport across sheared flows in tokamaks via effective transport coefficients, suggesting that such description is oversimplified and poorly captures the underlying dynamics, which may in turn compromise its predictive capabilities.

  19. On the nature of radial transport across sheared zonal flows in electrostatic ion-temperature-gradient gyrokinetic tokamak plasma turbulence

    SciTech Connect

    Sanchez, R.; Newman, D. E.; Leboeuf, J.-N.; Carreras, B. A.; Decyk, V. K.

    2009-05-15

    It is argued that the usual understanding of the suppression of radial turbulent transport across a sheared zonal flow based on a reduction in effective transport coefficients is, by itself, incomplete. By means of toroidal gyrokinetic simulations of electrostatic, ion-temperature-gradient turbulence, it is found instead that the character of the radial transport is altered fundamentally by the presence of a sheared zonal flow, changing from diffusive to anticorrelated and subdiffusive. Furthermore, if the flows are self-consistently driven by the turbulence via the Reynolds stresses (in contrast to being induced externally), radial transport becomes non-Gaussian as well. These results warrant a reevaluation of the traditional description of radial transport across sheared flows in tokamaks via effective transport coefficients, suggesting that such description is oversimplified and poorly captures the underlying dynamics, which may in turn compromise its predictive capabilities.

  20. Direct numerical simulation of Taylor-Couette flow subjected to a radial temperature gradient

    NASA Astrophysics Data System (ADS)

    Teng, Hao; Liu, Nansheng; Lu, Xiyun; Khomami, Bamin

    2015-12-01

    Direct numerical simulations have been performed to study the Taylor-Couette (TC) flow between two rotating, coaxial cylinders in the presence of a radial temperature gradient. Specifically, the influence of the buoyant force and the outer cylinder rotation on the turbulent TC flow system with the radius ratio η = 0.912 was examined. For the co-rotating TC flows with Rei (inner cylinder) =1000 and Reo (outer cylinder) =100, a transition pathway to highly turbulent flows is realized by increasing σ, a parameter signifying the ratio of buoyant to inertial force. This nonlinear flow transition involves four intriguing states that emerge in sequence as chaotic wavy vortex flow for σ = 0, wavy interpenetrating spiral flows for σ = 0.02 and 0.05, intermittent turbulent spirals for σ = 0.1 and 0.2, and turbulent spirals for σ = 0.4. Overall, the fluid motion changes from a centrifugally driven flow regime characterized by large-scale wavy Taylor vortices (TVs) to a buoyancy-dominated flow regime characterized by small-scale turbulent vortices. Commensurate changes in turbulence statistics and heat transfer are seen as a result of the weakening of large-scale TV circulations and enhancement of turbulent motions. Additionally, the influence of variation of the outer cylinder rotation, -500 < Reo < 500 in presence of buoyancy (σ = 0.1) with Rei = 1000, has been considered. Specifically, it is demonstrated that this variation strongly influences the azimuthal and axial mean flows with a weaker influence on the fluctuating fluid motions. Of special interest, here are the turbulent dynamics near the outer wall where a marked decrease of turbulence intensity and a sign inversion of the Reynolds stress Rrz are observed for the strongly counter-rotating regimes (Reo = - 300 and -500). To this end, it has been shown that the underlying flow physics for this drastic modification are associated with the modification of the correlation between the radial and axial fluctuating motions. In turn, the intriguing effects of this modification on the mean axial flow, turbulent statistics, force balance, and dynamic processes such as turbulence production and dissipation are discussed.

  1. An analytical solution for transient radial flow through unsaturated fractured porous media

    SciTech Connect

    Wu, Yu-Shu; Pan, Lehua

    2004-02-13

    This paper presents analytical solutions for one-dimensional radial transient flow through horizontal, unsaturated fractured rock formation. In these solutions, unsaturated flow through fractured media is described by a linearized Richards' equation, while fracture-matrix interaction is handled using the dual-continuum concept. Although linearizing Richards' equation requires a specially correlated relationship between relative permeability and capillary pressure functions for both fractures and matrix, these specially formed relative permeability and capillary pressure functions are still physically meaningful. These analytical solutions can thus be used to describe the transient behavior of unsaturated flow in fractured media under the described model conditions. They can also be useful in verifying numerical simulation results, which, as demonstrated in this paper, are otherwise difficult to validate.

  2. Intrapericardial denervation - Radial artery blood flow and heart rate responses to LBNP

    NASA Technical Reports Server (NTRS)

    Mckeever, Kenneth H.; Skidmore, Michael G.; Keil, Lanny C.; Sandler, Harold

    1990-01-01

    The effects of intrapericardial denervation on the radial artery blood flow velocity (RABFV) and heart rate (HR) responses to LBNP in rhesus monkeys were investigated by measuring the RABFV transcutaneously by a continuous-wave Doppler ultrasonic flowmeter in order to derive an index of forearm blood flow response to low (0 to -20 mm Hg) and high (0 to -60 mm Hg) ramp exposures during supine LBNP. Four of the eight subjects were subjected to efferent and afferent cardiac denervation. It was found that, during low levels of LBNP, monkeys with cardiac denervation exhibited no cardiopulmonary baroreceptor-mediated change in the RABFV or HR, unlike the intact animals, which showed steady decreases in RABFV during both high- and low-pressure protocols. It is suggested that forearm blood flow and HR responses to low-level LBNP, along with pharmacological challenge, are viable physiological tests for verifying the completeness of atrial and cardiopulmonary baroreceptor denervation.

  3. A cubic matrix-fracture geometry model for radial tracer flow in naturally fractured reservoirs

    SciTech Connect

    Jetzabeth Ramirez-Sabag; Fernando Samaniego V.

    1992-01-01

    This study presents a general solution for the radial flow of tracers in naturally fractured reservoirs, with cubic blocks matrix-fracture geometry. Continuous and finite step injection of chemical and radioactive tracers are considered. The reservoir is treated as being composed of two regions: a mobile where dispersion and convection take place and a stagnant where only diffusion and adsorption are allowed. Radioactive decay is considered in both regions. The model of this study is thoroughly compared under proper simplified conditions to those previously presented in the literature. The coupled matrix to fracture solution in the Laplace space is numerically inverted by means of the Crump algorithm. A detailed validation of the model with respect to solutions previously presented and/or simplified physical conditions solutions (i.e., homogeneous case) or limit solutions (i.e., naturally fractured nearly homogeneous) was carried out. The influence of the three of the main dimensionless parameters that enter into the solution was carefully investigated. A comparison of results for three different naturally fractured systems, vertical fractures (linear flow), horizontal fractures (radial flow) and the cubic geometry model of this study, is presented.

  4. Proton/pion ratios and radial flow in pp and peripheral heavy ion collisions

    NASA Astrophysics Data System (ADS)

    Cuautle, E.; Pai?, G.

    2006-09-01

    The production of baryon and mesons in the RHIC heavy-ion experiments has received a lot of attention lately. Although not widely known, the pp data measured concurrently with heavy ion collisions do not find a convincing explanation in terms of simple models. We present the results of an afterburner to Pythia and Hijing event generators, simulating radial flow which seems to qualitatively explain the experimental results when applied to the pp collision data from RHIC at 200 GeV center-of-mass energy.

  5. Proton/pion ratios and radial flow in pp and peripheral heavy ion collisions

    SciTech Connect

    Cuautle, E.; Paic, G.

    2006-09-25

    The production of baryon and mesons in the RHIC heavy-ion experiments has received a lot of attention lately. Although not widely known, the pp data measured concurrently with heavy ion collisions do not find a convincing explanation in terms of simple models. We present the results of an afterburner to Pythia and Hijing event generators, simulating radial flow which seems to qualitatively explain the experimental results when applied to the pp collision data from RHIC at 200 GeV center-of-mass energy.

  6. Identification of Phytoplankton from Flow Cytometry Data by Using Radial Basis Function Neural Networks

    PubMed Central

    Wilkins, M. F.; Boddy, Lynne; Morris, C. W.; Jonker, R. R.

    1999-01-01

    We describe here the application of a type of artificial neural network, the Gaussian radial basis function (RBF) network, in the identification of a large number of phytoplankton strains from their 11-dimensional flow cytometric characteristics measured by the European Optical Plankton Analyser instrument. The effect of network parameters on optimization is examined. Optimized RBF networks recognized 34 species of marine and freshwater phytoplankton with 91.5% success overall. The relative importance of each measured parameter in discriminating these data and the behavior of RBF networks in response to data from novel species (species not present in the training data) were analyzed. PMID:10508067

  7. Eigenmodes of Ducted Flows With Radially-Dependent Axial and Swirl Velocity Components

    NASA Technical Reports Server (NTRS)

    Kousen, Kenneth A.

    1999-01-01

    This report characterizes the sets of small disturbances possible in cylindrical and annular ducts with mean flow whose axial and tangential components vary arbitrarily with radius. The linearized equations of motion are presented and discussed, and then exponential forms for the axial, circumferential, and time dependencies of any unsteady disturbances are assumed. The resultant equations form a generalized eigenvalue problem, the solution of which yields the axial wavenumbers and radial mode shapes of the unsteady disturbances. Two numerical discretizations are applied to the system of equations: (1) a spectral collocation technique based on Chebyshev polynomial expansions on the Gauss-Lobatto points, and (2) second and fourth order finite differences on uniform grids. The discretized equations are solved using a standard eigensystem package employing the QR algorithm. The eigenvalues fall into two primary categories: a discrete set (analogous to the acoustic modes found in uniform mean flows) and a continuous band (analogous to convected disturbances in uniform mean flows) where the phase velocities of the disturbances correspond to the local mean flow velocities. Sample mode shapes and eigensystem distributions are presented for both sheared axial and swirling flows. The physics of swirling flows is examined with reference to hydrodynamic stability and completeness of the eigensystem expansions. The effect of assuming exponential dependence in the axial direction is discussed.

  8. Measurement of the Md3+/Md2+ reduction potential studied with flow electrolytic chromatography.

    PubMed

    Toyoshima, Atsushi; Li, Zijie; Asai, Masato; Sato, Nozomi; Sato, Tetsuya K; Kikuchi, Takahiro; Kaneya, Yusuke; Kitatsuji, Yoshihiro; Tsukada, Kazuaki; Nagame, Yuichiro; Schdel, Matthias; Ooe, Kazuhiro; Kasamatsu, Yoshitaka; Shinohara, Atsushi; Haba, Hiromitsu; Even, Julia

    2013-11-01

    The reduction behavior of mendelevium (Md) was studied using a flow electrolytic chromatography apparatus. By application of the appropriate potentials on the chromatography column, the more stable Md(3+) is reduced to Md(2+). The reduction potential of the Md(3+) + e(-) ? Md(2+) couple was determined to be -0.16 0.05 V versus a normal hydrogen electrode. PMID:24116851

  9. A high power density radial-in-flow reactor split core design for space power systems

    NASA Astrophysics Data System (ADS)

    Coomes, Edmund P.

    Application of the Rankine cycle to space power systems is difficult because of the problems and complexities associated with two phase flow systems in microgravity. A direct cycle system which could provide super heated vapor to the turbine inlet would greatly enhance the development of Rankine cycle power systems for space applications. The split core radial-in-flow reactor design provides a safe reliable core design for space power systems. It makes direct Rankine cycle power systems a very competitive design, eliminating the boiler and additional pumps of an indirect cycle along with the liquid vapor separator. A continuous power Rankine cycle system using this core design would produce the least weight system of any having the same power output.

  10. Evidence for Radial Flow of Thermal Dileptons in High-Energy Nuclear Collisions

    SciTech Connect

    Arnaldi, R.; Colla, A.; Cortese, P.; Ferretti, A.; Oppedisano, C.; Scomparin, E.; Banicz, K.; Damjanovic, S.; Castor, J.; Devaux, A.; Fargeix, J.; Force, P.; Manso, F.; Chaurand, B.; Cicalo, C.; Falco, A. de; Floris, M.; Masoni, A.; Puddu, G.; Serci, S.

    2008-01-18

    The NA60 experiment at the CERN SPS has studied low-mass dimuon production in 158A GeV In-In collisions. An excess of pairs above the known meson decays has been reported before. We now present precision results on the associated transverse momentum spectra. The slope parameter T{sub eff} extracted from the spectra rises with dimuon mass up to the {rho}, followed by a sudden decline above. While the initial rise is consistent with the expectations for radial flow of a hadronic decay source, the decline signals a transition to an emission source with much smaller flow. This may well represent the first direct evidence for thermal radiation of partonic origin in nuclear collisions.

  11. A study of radial-flow turbomachinery blade vibration measurements using Eulerian laser Doppler vibrometry

    NASA Astrophysics Data System (ADS)

    Oberholster, A. J.; Heyns, P. S.

    2014-05-01

    The structural integrity of blades is critical to the health of turbomachinery. Since operational failure of these blades can possibly lead to catastrophic failure of the machine, it is important to have knowledge of blade conditions in an online fashion. Due to several practical implications, it is desired to measure blade vibration with a non-contact technique. The application of laser Doppler vibrometry towards the vibration based condition monitoring of axial-flow turbomachinery blades has been successfully demonstrated in previous work. In this paper the feasibility of using laser Doppler vibrometry to measure radial-flow turbomachinery blade vibrations is investigated with the aid of digital image correlation and strain gauge telemetry.

  12. A PC-based inverse design method for radial and mixed flow turbomachinery

    NASA Technical Reports Server (NTRS)

    Skoe, Ivar Helge

    1991-01-01

    An Inverse Design Method suitable for radial and mixed flow turbomachinery is presented. The codes are based on the streamline curvature concept; therefore, it is applicable for current personal computers from the 286/287 range. In addition to the imposed aerodynamic constraints, mechanical constraints are imposed during the design process to ensure that the resulting geometry satisfies production consideration and that structural considerations are taken into account. By the use of Bezier Curves in the geometric modeling, the same subroutine is used to prepare input for both aero and structural files since it is important to ensure that the geometric data is identical to both structural analysis and production. To illustrate the method, a mixed flow turbine design is shown.

  13. Flow regimes in a vertical Taylor-Couette system with a radial thermal gradient

    NASA Astrophysics Data System (ADS)

    Guillerm, R.; Kang, C.; Savaro, C.; Lepiller, V.; Prigent, A.; Yang, K.-S.; Mutabazi, I.

    2015-09-01

    A rich variety of flow regimes in a Newtonian fluid inside a vertical large-aspect ratio and a wide-gap Taylor-Couette system with a radial temperature gradient has been determined in experiments and in direct numerical simulations (DNSs). Compared to previous experiments and numerical studies, a wider range of temperature differences (i.e., of the Grashof number Gr) and of the rotation rate (the Taylor number Ta) has been covered. The combined effect of rotation and of the radial temperature gradient is the occurrence of helicoidal vortices or modulated waves at the onset. Stationary axisymmetric vortices are found for very weak temperature differences. A good agreement was found for critical states between results from experiments, linear stability analysis, and DNS. Higher instability modes have been determined for a wide range of parameters and a state diagram of observable flow regimes has been established in the plane spanned by Gr and Ta. Some higher states observed in experiments were retrieved in DNS.

  14. Electromagnetic gauge for measuring the radial particle velocity in 2-D flow

    NASA Astrophysics Data System (ADS)

    Rosenberg, G.; Yaziv, D.; Mayseless, M.

    1982-04-01

    Applications of existing EMV gauges are limited for uniaxial strain configurtions, since the gauge length must remain fixed during the motion. A modification of the electromagnetic technique which provides measurements in 2-D flow is presented. When the problem of a projectile impacting a target is described in cylindrical coordinates (r,z) with z as axis of symmetry, the flow can be defined by the particle velocity components Uz,Ur. A new gauge is made of a thin copper wire having a circular turn shape. The gauge is embedded in the target material in a plane normal to the z axis axisymetrically. Magnetic field is generated by a solenoid wrapped around the target so that the field lines are parallel to the z axis. In a configuration like this, only the radial motion contributes to the EMF, therefore in a uniform filed, B, the measured EMF depends on the radial particle velocity: E=2πBr(t)Ur(t), where the circular turn radius, r(t), is obtained by integrating the velocity Ur(t). This new method hjas been demonstrted by experiment, impacting a rod shaped projectile made of PMMA into a target of the same material. Results are compared with 2-D calculation.

  15. Optimization and evaluation of radially interconnected versus bifurcating flow distributors using computational fluid dynamics modelling.

    PubMed

    Davydova, E; Deridder, S; Eeltink, S; Desmet, G; Schoenmakers, P J

    2015-02-01

    Two main groups of flow distributors, viz. "bifurcating distributors" (BF) and "radially interconnected distributors" (RI), as well as some hybrid distributors were investigated. Computational fluid dynamics was used to evaluate the performance of the distributors and to establish the design yielding the most uniform velocity field and the smallest variance for the bands emerging from the distributor. A minimum channel width of 100 ?m was considered to allow the use of micro-milling techniques for chip fabrication. The main factors that influenced the values of band variances were identified. The performance of the distributors was found to correlate most strongly with the volume of the flow distributors. The separation bed should be positioned immediately after, but not against the flow distributor. It was concluded that BF distributors perform best in terms of band variance. The values of band variances for the BF distributor decreased with increasing angle between bifurcation branches and the lowest value of about 0.01 mm(2) was found for ?=175. Both BF and RI flow distributors were found to perform reasonably well when imperfections were present in the structure. However, severe blockages (exceeding 75% of the cross-sectional area and length) of channels in, especially, BF flow distributors may jeopardize their performance. PMID:25591402

  16. Viscous potential flow analysis of radial fingering in a Hele-Shaw cell

    NASA Astrophysics Data System (ADS)

    Joseph, Daniel D.; Kim, Hyungjun; Funada, Toshio

    2008-11-01

    The problem of radial fingering in two-phase gas/liquid flow in a Hele-Shaw cell under injection of gas is studied here. The fingers arise as an instability of a time dependent flow which is rigorously resolved in the linearized approximation for the first time. One consequence of the unsteady basic flow is continuous nucleation of new finger as the radius R(t) of the unperturbed interface increases. Another consequence is that the evolution of the perturbed interface f(R(t)) is not governed by the local (in time) value of the unperturbed interface R(t) but depends globally on all past values of R(t) up to the present. The problem is analyzed as a viscous potential flow VPF in which the potential flow analysis of Paterson (1981) [J. Fluid Mech. 113, 513] and others is augmented to account for the effects of viscosity on the normal stress at the gas/liquid interface. The unstable cases in which gas is injected into liquid or liquid is withdrawn from gas lead to fingers. Here we show that the viscous normal stress should not be neglected.

  17. Radial patterns of sap flow in woody stems of dominant and understory species: scaling errors associated with positioning of sensors.

    PubMed

    Nadezhdina, Nadezhda; Cermk, Jan; Ceulemans, Reinhart

    2002-09-01

    We studied sap flow in dominant coniferous (Pinus sylvestris L.) and broadleaf (Populus canescens L.) species and in understory species (Prunus serotina Ehrh. and Rhododendron ponticum L.) by the heat field deformation (HFD) method. We attempted to identify possible errors arising during flow integration and scaling from single-point measurements to whole trees. Large systematic errors of -90 to 300% were found when it was assumed that sap flow was uniform over the sapwood depth. Therefore, we recommend that the radial sap flow pattern should be determined first using sensors with multiple measuring points along a stem radius followed by single-point measurements with sensors placed at a predetermined depth. Other significant errors occurred in the scaling procedure even when the sap flow radial pattern was known. These included errors associated with uncertainties in the positioning of sensors beneath the cambium (up to 15% per 1 mm error in estimated xylem depth), and differences in environmental conditions when the radial profile applied for integration was determined over the short term (up to 47% error). High temporal variation in the point-to-area correction factor along the xylem radius used for flow integration is also problematic. Compared with midday measurements, measurements of radial variation of sap flow in the morning and evening of sunny days minimized the influence of temporal variations on the point-to-area correction factor, which was especially pronounced in trees with a highly asymmetric sap flow radial pattern because of differences in functioning of the sapwood xylem layers. Positioning a single-point sensor at a depth with maximum sap flow is advantageous because of the high sensitivity of maximum sap flow to water stress conditions and changes in micro-climate, and because of the lower random errors associated with the positioning of a single-point sensor along the xylem radius. PMID:12204847

  18. An interactive grid generation procedure for axial and radial flow turbomachinery

    NASA Technical Reports Server (NTRS)

    Beach, Timothy A.

    1989-01-01

    A combination algebraic/elliptic technique is presented for the generation of three dimensional grids about turbo-machinery blade rows for both axial and radial flow machinery. The technique is built around use of an advanced engineering workstation to construct several two dimensional grids interactively on predetermined blade-to-blade surfaces. A three dimensional grid is generated by interpolating these surface grids onto an axisymmetric grid. On each blade-to-blade surface, a grid is created using algebraic techniques near the blade to control orthogonality within the boundary layer region and elliptic techniques in the mid-passage to achieve smoothness. The interactive definition of bezier curves as internal boundaries is the key to simple construction. This procedure lends itself well to zonal grid construction, an important example being the tip clearance region. Calculations done to date include a space shuttle main engine turbopump blade, a radial inflow turbine blade, and the first stator of the United Technologies Research Center large scale rotating rig. A finite Navier-Stokes solver was used in each case.

  19. An interactive grid generation procedure for axial and radial flow turbomachinery

    NASA Astrophysics Data System (ADS)

    Beach, T. A.

    1990-01-01

    A combination algebraic/elliptic technique is presented for the generation of three dimensional grids about turbo-machinery blade rows for both axial and radial flow machinery. The technique is built around use of an advanced engineering workstation to construct several two dimensional grids interactively on predetermined blade-to-blade surfaces. A three dimensional grid is generated by interpolating these surface grids onto an axisymmetric grid. On each blade-to-blade surface, a grid is created using algebraic techniques near the blade to control orthogonality within the boundary layer region and elliptic techniques in the mid-passage to achieve smoothness. The interactive definition of bezier curves as internal boundaries is the key to simple construction. This procedure lends itself well to zonal grid construction, an important example being the tip clearance region. Calculations done to date include a space shuttle main engine turbopump blade, a radial inflow turbine blade, and the first stator of the United Technologies Research Center large scale rotating rig. A finite Navier-Stokes solver was used in each case.

  20. Neoclassical calculations of radial electric field and plasma flow in HSX beyond the monoenergetic assumption

    NASA Astrophysics Data System (ADS)

    Smoniewski, J.; Talmadge, J. N.; Kumar, S. T. A.; Satake, S.; Landreman, M.

    2014-10-01

    The radial electric field in the plasma core has been measured to be in the range of 2-5 kV/m during ECRH. The measured value is in good agreement with the ion root electric field calculated using the neoclassical code PENTA. However, PENTA also calculates that there should be a large electron root very close to the axis on the order of 30-50 kV/m. To date, no evidence of this electric field has been found. The PENTA code is a momentum conserving extension of the DKES code. The underlying DKES code makes a monoenergetic approximation which is known to break down when the electric field is near resonant values. We present electric field and plasma flow results from the SFINCS and FORTEC-3D codes, neither of which make the monoenergetic assumption, to benchmark the PENTA calculations. SFINCS is a drift-kinetic continuum code, and FORTEC-3D is a Monte Carlo code that also retains radial coupling. Initial results appear to show little difference between the three codes for HSX relevant parameters. In addition, we present recent results from bias probe experiments. Supported by US DoE award DE-FG02-93ER54222.

  1. Three-dimensional flow in radial turbomachinery and its impact on design

    NASA Technical Reports Server (NTRS)

    Tan, Choon S.; Hawthorne, William

    1993-01-01

    In the two papers on the 'Theory of Blade Design for Large Deflections' published in 1984, a new inverse design technique was presented for designing the shape of turbomachinery blades in three-dimensional flow. The technique involves the determination of the blade profile from the specification of a distribution of the product of the radius and the pitched averaged tangential velocity (i.e., r bar-V(sub theta), the mean swirl schedule) within the bladed region. This is in contrast to the conventional inverse design technique for turbomachinery blading in two dimensional flow in which the blade surface pressure or velocity distribution is specified and the blade profile determined as a result; this is feasible in two-dimensional flow because the streamlines along the blade surfaces are known a priori. However, in three-dimensional flow, the stream surface is free to deform within the blade passage so that the streamlines on the blade surfaces are not known a priori; thus it is difficult and not so useful to prescribe the blade surface pressure or velocity distribution and determine the resulting blade profile. It therefore seems logical to prescribe the swirl schedule within the bladed region for designing a turbomachinery blade profile in three-dimensional flow. Furthermore, specifying r bar-V(sub theta) has the following advantages: (1) it is related to the circulation around the blade (i.e., it is an aerodynamic quantity); (2) the work done or extracted is approximately proportional to the overall change in r bar-V(sub theta) across a given blade row (Euler turbine equation); and (3) the rate of change of r bar-V(sub theta) along the mean streamline at the blade is related to the pressure jump across the blade and therefore the blade loading. Since the publications of those two papers, the technique has been applied to the design of a low speed as well as a high speed radial inflow turbine (for turbocharger applications) both of which showed definite improvements in performance over that of wheels of conventional designs, the design study of a high pressure ratio radial inflow turbine with and without splitter blades.

  2. Modelling and simulation of a novel multi-radial-flow CVD reactor

    NASA Astrophysics Data System (ADS)

    Yoo, C.-S.; Dixon, A. G.

    1989-09-01

    A high-capacity novel CVD reactor is proposed. A mathematical model has been formulated, solved numerically and simulations run to show the effects of design variables for the novel CVD reactor. The novel reactor configuration offers a dramatic increase in wafer capacity. A hydrodynamic model based on the classical treatment of the radial-flow catalytic reactor was used to analyze the gas distribution to wafers along the entire reactor axis. Film growth rates were obtained from a model based on chemical reaction engineering principles, using published kinetics for silicon deposition. The simulation results indicated that the reactor dimensions and operating conditions can be specified in such a way as to give good cross-wafer and susceptor-to-susceptor film uniformity.

  3. Experiments on Thermal Convection in Rotating Spherical Shells With Radial Gravity: The Geophysical Fluid Flow Cell

    NASA Technical Reports Server (NTRS)

    Hart, John E.

    1996-01-01

    Experiments designed to study the fluid dynamics of buoyancy driven circulations in rotating spherical shells were conducted on the United States Microgravity Laboratory 2 spacelab mission. These experiments address several aspects of prototypical global convection relevant to large scale motions on the Sun, Earth, and on the giant planets. The key feature is the consistent modeling of radially directed gravity in spherical geometry by using dielectric polarization forces. Imagery of the planforms of thermally driven flows for rapidly-rotating regimes shows an initial separation and eventual merger of equatorial and polar convection as the heating (i.e. the Rayleigh number) is increased. At low rotation rates, multiple-states of motion for the same external parameters were observed.

  4. Raman scattering of InGaAs/InP grown by uniform radial flow epitaxy

    NASA Technical Reports Server (NTRS)

    Feng, Z. C.; Allerman, A. A.; Barnes, P. A.; Perkowitz, S.

    1992-01-01

    Uniform radial flow epitaxy, a novel growth technique, has been used to grown InGaAs films on InP. Epitaxial layers above and below the critical thickness for the onset of slip were grown. Raman spectroscopy was used to characterize the quality of epitaxial layers, determine alloy composition, and measure the strain. Raman spectra from both pseudomorphic (strained) and relaxed (unstrained) InGaAs films were obtained at 300 and 80 K. The difference in the frequencies of their GaAs-like longitudinal optical phonons was used to calculate stress for the strained InGaAs/InP, leading to a direct formula for the evaluation of the layer stress.

  5. Estimated Performance of Radial-Flow Exit Nozzles for Air in Chemical Equilibrium

    NASA Technical Reports Server (NTRS)

    Englert, Gerald W.; Kochendorfer, Fred D.

    1959-01-01

    The thrust, boundary-layer, and heat-transfer characteristics were computed for nozzles having radial flow in the divergent part. The working medium was air in chemical equilibrium, and the boundary layer was assumed to be all turbulent. Stagnation pressure was varied from 1 to 32 atmospheres, stagnation temperature from 1000 to 6000 R, and wall temperature from 1000 to 3000 R. Design pressure ratio was varied from 5 to 320, and operating pressure ratio was varied from 0.25 to 8 times the design pressure ratio. Results were generalized independent of divergence angle and were also generalized independent of stagnation pressure in the temperature range of 1000 to 3000 R. A means of determining the aerodynamically optimum wall angle is provided.

  6. PIV investigation of the flow induced by a passive surge control method in a radial compressor

    NASA Astrophysics Data System (ADS)

    Guillou, Erwann; Gancedo, Matthieu; Gutmark, Ephraim; Mohamed, Ashraf

    2012-09-01

    Due to recent emission regulations, the use of turbochargers for force induction of internal combustion engines has increased. Actually, the trend in diesel engines is to downsize the engine by use of turbochargers that operate at higher pressure ratios. Unfortunately, increasing the impeller rotational speed of turbocharger radial compressors tends to reduce their range of operation, which is limited at low mass flow rate by the occurrence of surge. In order to extend the operability of turbochargers, compressor housings can be equipped with a passive surge control device such as a "ported shroud." This specific casing treatment has been demonstrated to enhance the surge margin with minor negative impact on the compressor efficiency. However, the actual working mechanisms of the system remain not well understood. Hence, in order to optimize the design of the ported shroud, it is crucial to identify the dynamic flow changes induced by the implementation of the device to control instabilities. From the full dynamic survey of the compressor performance characteristics obtained with and without ported shroud, specific points of operation were selected to carry out planar flow visualization. At normal working, both standard and stereoscopic particle imaging velocimetry (PIV) measurements were performed to evaluate instantaneous and mean velocity flow fields at the inlet of the compressor. At incipient and full surge, phase-locked PIV measurements were added. As a result, satisfying characterization of the compressor instabilities was provided at different operational speeds. Combining transient pressure data and PIV measurements, the time evolution of the complex flow patterns occurring at surge was reconstructed and a better insight into the bypass mechanism was achieved.

  7. Radial-radial single rotor turbine

    SciTech Connect

    Platts, David A.

    2006-05-16

    A rotor for use in turbine applications has a radial compressor/pump having radially disposed spaced apart fins forming passages and a radial turbine having hollow turbine blades interleaved with the fins and through which fluid from the radial compressor/pump flows. The rotor can, in some applications, be used to produce electrical power.

  8. The radial flow planetary reactor: low pressure versus atmospheric pressure MOVPE

    NASA Astrophysics Data System (ADS)

    Frijlink, P. M.; Nicolas, J. L.; Ambrosius, H. P. M. M.; Linders, R. W. M.; Waucquez, C.; Marchal, J. M.

    1991-12-01

    A comparison between MOVPE of III-V compounds with the radial flow planetary reactor at atmospheric pressure and at reduced pressure has been carried out by numerical simulation and experimentally. The behavior of the reactor at low pressure was found to be very similar to that at atmospheric pressure. The obtained layer thickness uniformity was also 1% at pressures of 100 mbar and 200 mbar. Moreover, the uniformity was found to be almost independent of total mass flow, over the range of 10 to 43 SLM. The first growth on five 3 inch diameter wafers at atmospheric pressure is reported. Optimization of the inlet section led to simultaneous uniformities of ? 1% in layer thickness abd sheet resistance. The first GaAs-(Ga,Al)As lasers grown with this reactor at 200 mbar are reported, with a threshold current density of 400 A/cm 2. The first GaAs-(Ga,In)As-(Ga,Al)As pseudomorphic HEMT material grown with this reactor at atmospheric pressure with 22% indium in the channel layer yielded devices with an average maximum transconductance of 383 mS/mm and unity current gain cut-off frequency of 64.5 GHz for a gate length of 0.25 ?m.

  9. The Potential Effects of a Biofeedback Writing Exercise on Radial Artery Blood Flow and Neck Mobility

    PubMed Central

    Krullaards, Rob L.; Pel, Johan J. M.; Snijders, Chris J.; Kleinrensink, Gert-Jan

    2009-01-01

    Background: It has been suggested that sustained contraction of the deep neck muscles may reduce axial cervical range of motion (CROM) and radial artery blood flow velocity (vrad.art.mean). No studies have reported both phenomena in relation to acute hand, shoulder or neck trauma. Procedures: The CROM and vrad.art.mean were measured in 20 police officers prior to and immediately after a 2-hours drive on a motorcycle and immediately after a 1-minute writing exercise using biofeedback. The CROM was measured using separate inclinometers and the vrad.art.mean was measured in both arms just proximal to the wrist using echo-Doppler. Findings: During the study, one officer had a motorcycle accident resulting in acute symptoms of neck trauma. His vrad.art.mean was acutely reduced by 73% (right arm) and 45% (left arm). Writing with biofeedback increased his vrad.art.mean by 150% (right arm) and 80% (left arm). In the remaining 19 officers, the CROM to the right was significantly increased after the 2-hours driving task (p<0.05; paired subject t-test). Writing with biofeedback increased their CROM in both directions and vrad.art.mean in both arms (p<001). Conclusions: A 2-hours drive showed modest physical changes in the upper extremities. Biofeedback in writing tasks might relate to the influence of relaxation and diverting attention for neck mobility and arterial blood flow improvement. PMID:23675136

  10. Study of Radially Varying Magnetic Field on Blood Flow through Catheterized Tapered Elastic Artery with Overlapping Stenosis

    NASA Astrophysics Data System (ADS)

    Nadeem, S.; Ijaz, S.

    2015-11-01

    A precise model has been developed for studying the influence of metallic nanoparticles on blood flow through catheterized tapered elastic arteries with radially varying magnetic field. The model is solved under the mild stenosis approximation by considering blood as viscous fluid. The influence of different flow parameters associated with this problem such as Hartmann number, nanoparticle volume fraction, Grashof number and heat source or sink parameter is analyzed by plotting the graphs of the wall shear stress, resistance impedance to blood flow and stream lines. The influence of the radially varying magnetic field on resistance impedance to flow is analyzed and it is observed that the significantly strong magnetic force tends to increase in resistance.

  11. Evaluation of Radial Flow Fluidized Filter (R3F) Followed by Microfiltration and Ultrafiltration Systems in Calimesa, California

    EPA Science Inventory

    U.S. EPA coordinated a field study with South Mesa Water Utility to look for treatment alternatives for California State Project Water in the small community of Calimesa, California. EPA evaluated the performance of a system comprised of Radial Flow Fluidized Filtration (R3f) fo...

  12. 1r2dinv: A finite-difference model for inverse analysis of two dimensional linear or radial groundwater flow

    USGS Publications Warehouse

    Bohling, G.C.; Butler, J.J., Jr.

    2001-01-01

    We have developed a program for inverse analysis of two-dimensional linear or radial groundwater flow problems. The program, 1r2dinv, uses standard finite difference techniques to solve the groundwater flow equation for a horizontal or vertical plane with heterogeneous properties. In radial mode, the program simulates flow to a well in a vertical plane, transforming the radial flow equation into an equivalent problem in Cartesian coordinates. The physical parameters in the model are horizontal or x-direction hydraulic conductivity, anisotropy ratio (vertical to horizontal conductivity in a vertical model, y-direction to x-direction in a horizontal model), and specific storage. The program allows the user to specify arbitrary and independent zonations of these three parameters and also to specify which zonal parameter values are known and which are unknown. The Levenberg-Marquardt algorithm is used to estimate parameters from observed head values. Particularly powerful features of the program are the ability to perform simultaneous analysis of heads from different tests and the inclusion of the wellbore in the radial mode. These capabilities allow the program to be used for analysis of suites of well tests, such as multilevel slug tests or pumping tests in a tomographic format. The combination of information from tests stressing different vertical levels in an aquifer provides the means for accurately estimating vertical variations in conductivity, a factor profoundly influencing contaminant transport in the subsurface. ?? 2001 Elsevier Science Ltd. All rights reserved.

  13. Experimental evaluation of connectivity influence on dispersivity under confined and unconfined radial convergent flow conditions

    NASA Astrophysics Data System (ADS)

    Guzzi, Silvia; Molinari, Antonio; Fallico, Carmine; Pedretti, Daniele

    2014-05-01

    Heterogeneity and connectivity have a significant impact on the fate and transport of contaminants due to the occurrence of formations with largest permeability than the surrounding geological materials, which can originate preferential pathways in groundwater system. These issues are usually addressed by tracer tests and a radial convergent (RC) flow setting is typically selected for convenience but more complicated for model interpretation than uniform flow transport. An experimental investigation was performed using RC tracer tests in a 3D intermediate scale physical model to illustrate the role of connected features on the estimation of dispersivity using the classical Sauty solution and the method of moments, under confined and unconfined aquifer conditions. The physical model consists of 26 piezometers located at difference distances from a constant-discharge central pumping well. The box is filled with gravel channels embedded in a sandy matrix and organized in different layers. Materials have been well characterized before and after the test. For the confined configuration, a silt layer was placed above the previous layers. Tracer tests were performed using potassium iodide solutions with concentration of 310-3 M and under a constant pumping flow rate of 0.05 L/s. To mimic a pulse injection in each piezometer we used syringes and pipes, whereas a probe allowed continuous measuring of tracer concentration. Average velocity and longitudinal dispersion coefficient were defined from the first and second central moment of the observed breakthrough curves for each piezometer (integrated over the outflow boundary of the domain) and using the classical curve matching from the Sauty's solution at different Pclet numbers. Results reveal in some cases that estimates of hydrodynamic parameters from the Sauty solution and the method of moments seem to be different. This is related to the different basic assumptions of the two methods applied, and especially because of the presence of preferential flow paths which have been found to strongly control the highest values of the average velocity at the source and affect the resulting longitudinal dispersion coefficient. This study showed additional lights on the impact of connectivity on transport and its role to obtain effective measurements of macrodispersion throughout the aquifer under RC transport. Reference: Fernndez-Garcia D. et al. (2002) Convergent-flow tracer tests in heterogeneous media. Journal of Contaminant Hydrology 57 129-145. Fischer H. B. (1966) Longitudinal Dispersion in Laboratory and Natural Streams. Technical Rep. KH-R-12, California Institute of Technology, Pasadena, California. Gaspar E. (1987) Modern Trends in Tracer Hydrology, Volume II. CRC Press, Inc., Boca Raton, FL, USA.

  14. Flow Characterization and Dynamic Analysis of a Radial Compressor with Passive Method of Surge Control

    NASA Astrophysics Data System (ADS)

    Guillou, Erwann

    Due to recent emission regulations, the use of turbochargers for force induction of internal combustion engines has increased. Actually, the trend in diesel engines is to downsize the engine by use of turbochargers that operate at higher pressure ratio. Unfortunately, increasing the rotational speed tends to reduce the turbocharger radial compressor range of operation which is limited at low mass flow rate by the occurrence of surge. In order to extent the operability of turbochargers, compressor housings can be equipped with a passive surge control device also known as ported shroud. This specific casing treatment has been demonstrated to enhance surge margin with minor negative impact on the compressor efficiency. However, the actual working mechanisms of the bypass system remain not well understood. In order to optimize the design of the ported shroud, it is then crucial to identify the dynamic flow changes induced by the implementation of the device to control instabilities. Experimental methods were used to assess the development of instabilities from stable, stall and eventually surge regimes of a ported shroud centrifugal compressor. Systematic comparison was conducted with the same compressor design without ported shroud. Hence, the full pressure dynamic survey of both compressors' performance characteristics converged toward two different and probably interrelated driving mechanisms to the development and/or propagation of unsteadiness within each compressor. One related the pressure disturbances at the compressor inlet, and notably the more apparent development of perturbations in the non-ported compressor impeller, whereas the other was attributed to the pressure distortions induced by the presence of the tongue in the asymmetric design of the compressor volute. Specific points of operation were selected to carry out planar flow measurements. At normal working, both standard and stereoscopic particle imaging velocimetry (PIV) measurements were performed to calculate the instantaneous and mean velocity fields at the inlet of the compressor. At incipient and full surge, phase-locked PIV measurements were added. In this work, satisfying characterization of the compressor inlet flow instabilities was obtained at different operational speeds. Combining transient pressure data and PIV measurements, the time evolution of the complex flow patterns occurring at surge was reconstructed and a better insight into the bypass mechanisms was achieved.

  15. Proximal radial artery ligation after distalization of a high flow brachio-cephalic fistula. A novel approach to inflow reduction.

    PubMed

    Smith, J B; Calder, F R

    2008-01-01

    High flow fistulae present a common challenge to vascular access (VA) surgeons and many strategies have been described, each with their benefits and limitations. There are no NK-DOQI guidelines for the management of high flow fistulae or indeed the management of those refractory to more conventional approaches. We discuss a novel technique to inflow reduction in a previously distalized brachiocephalic fistula and recommend the technique of proximal radial artery ligation. PMID:19085900

  16. Theoretical analysis of inertially irrotational and solenoidal flow in two-dimensional radial-flow pump and turbine impellers with equiangular blades

    SciTech Connect

    Visser, F.C.; Brouwers, J.J.H.; Badie, R.

    1994-06-01

    Using the theory of functions of a complex variable, in particular the method of conformal mapping, the irrotational and solenoidal flow in two-dimensional radial-flow pump and turbine impellers fitted with equiangular blades is analyzed. Exact solutions are given for the fluid velocity along straight radial pump and turbine impeller blades, while for logarithmic spiral pump impeller blades solutions are given which hold asymptotically as (r(sub 1)/r(sub 2))(exp n) approaches 0, in which r(sub 1) is impeller inner radius, r(sub 2) is impeller outer radius, and n is the number of blades. Both solutions are given in terms of a Fourier series, with the Fourier coefficients being given by the (Gauss) hypergeometric function and the beta function respectively. The solutions are used to derive analytical expressions for a number of parameters which are important for practical design of radial turbomachinery, and which reflect the two-dimensional nature of the flow field. Parameters include rotational slip of the flow leaving radial impellers, conditions to avoid reverse flow between impeller blades, and conditions for shockless flow at impeller entry, with the number of blades and blade curvature as variables. Furthermore, analytical extensions to classical one-dimensional Eulerian-based expressions for developed head of pumps and delivered work of turbines are given. 30 refs.

  17. A Miniature Radial-Flow Wind Turbine Using Piezoelectric Transducers and Magnetic Excitation

    NASA Astrophysics Data System (ADS)

    Fu, H.; Yeatman, E. M.

    2015-12-01

    This paper presents a miniature radial-flow piezoelectric wind turbine for harvesting airflow energy. The turbine's transduction is achieved by magnetic pluckingof a piezoelectric beam by the passing rotor. The magnetic coupling is formed by two magnets on the beam's free end and on the rotor plate. Frequency up-conversion is realized by the magnetic excitation, allowing the rotor to rotate at any low frequency while the beam can vibrate at its resonant frequency after each plucking. The operating range of the device is, therefore, expanded by this mechanism. Two arrangements of magnetic orientation have been investigated, showing that the repulsive arrangement has higher output power. The influence of the vertical gap between magnets was also examined, providing guidance for the final design. A prototype was built and tested in a wind tunnel. A peak power output of 159 ?W was obtained with a 270 k? load at 2.7 m/s airflow speed. The device started working at 3.5 m/s and kept operating when the airflow speed fell to 1.84 m/s.

  18. Linear stability of a circular Couette flow under a radial thermoelectric body force.

    PubMed

    Yoshikawa, H N; Meyer, A; Crumeyrolle, O; Mutabazi, I

    2015-03-01

    The stability of the circular Couette flow of a dielectric fluid is analyzed by a linear perturbation theory. The fluid is confined between two concentric cylindrical electrodes of infinite length with only the inner one rotating. A temperature difference and an alternating electric tension are applied to the electrodes to produce a radial dielectrophoretic body force that can induce convection in the fluid. We examine the effects of superposition of this thermoelectric force with the centrifugal force including its thermal variation. The Earth's gravity is neglected to focus on the situations of a vanishing Grashof number such as microgravity conditions. Depending on the electric field strength and of the temperature difference, critical modes are either axisymmetric or nonaxisymmetric, occurring in either stationary or oscillatory states. An energetic analysis is performed to determine the dominant destabilizing mechanism. When the inner cylinder is hotter than the outer one, the circular Couette flow is destabilized by the centrifugal force for weak and moderate electric fields. The critical mode is steady axisymmetric, except for weak fields within a certain range of the Prandtl number and of the radius ratio of the cylinders, where the mode is oscillatory and axisymmetric. The frequency of this oscillatory mode is correlated with a Brunt-Visl frequency due to the stratification of both the density and the electric permittivity of the fluid. Under strong electric fields, the destabilization by the dielectrophoretic force is dominant, leading to oscillatory nonaxisymmetric critical modes with a frequency scaled by the frequency of the inner-cylinder rotation. When the outer cylinder is hotter than the inner one, the instability is again driven by the centrifugal force. The critical mode is axisymmetric and either steady under weak electric fields or oscillatory under strong electric fields. The frequency of the oscillatory mode is also correlated with the Brunt-Visl frequency. PMID:25871198

  19. Linear stability of a circular Couette flow under a radial thermoelectric body force

    NASA Astrophysics Data System (ADS)

    Yoshikawa, H. N.; Meyer, A.; Crumeyrolle, O.; Mutabazi, I.

    2015-03-01

    The stability of the circular Couette flow of a dielectric fluid is analyzed by a linear perturbation theory. The fluid is confined between two concentric cylindrical electrodes of infinite length with only the inner one rotating. A temperature difference and an alternating electric tension are applied to the electrodes to produce a radial dielectrophoretic body force that can induce convection in the fluid. We examine the effects of superposition of this thermoelectric force with the centrifugal force including its thermal variation. The Earth's gravity is neglected to focus on the situations of a vanishing Grashof number such as microgravity conditions. Depending on the electric field strength and of the temperature difference, critical modes are either axisymmetric or nonaxisymmetric, occurring in either stationary or oscillatory states. An energetic analysis is performed to determine the dominant destabilizing mechanism. When the inner cylinder is hotter than the outer one, the circular Couette flow is destabilized by the centrifugal force for weak and moderate electric fields. The critical mode is steady axisymmetric, except for weak fields within a certain range of the Prandtl number and of the radius ratio of the cylinders, where the mode is oscillatory and axisymmetric. The frequency of this oscillatory mode is correlated with a Brunt-Visl frequency due to the stratification of both the density and the electric permittivity of the fluid. Under strong electric fields, the destabilization by the dielectrophoretic force is dominant, leading to oscillatory nonaxisymmetric critical modes with a frequency scaled by the frequency of the inner-cylinder rotation. When the outer cylinder is hotter than the inner one, the instability is again driven by the centrifugal force. The critical mode is axisymmetric and either steady under weak electric fields or oscillatory under strong electric fields. The frequency of the oscillatory mode is also correlated with the Brunt-Visl frequency.

  20. The galactic habitable zone of the Milky Way and M31 from chemical evolution models with gas radial flows

    NASA Astrophysics Data System (ADS)

    Spitoni, E.; Matteucci, F.; Sozzetti, A.

    2014-05-01

    The galactic habitable zone is defined as the region with sufficient abundance of heavy elements to form planetary systems in which Earth-like planets could be born and might be capable of sustaining life, after surviving to close supernova explosion events. Galactic chemical evolution models can be useful for studying the galactic habitable zones in different systems. We apply detailed chemical evolution models including radial gas flows to study the galactic habitable zones in our Galaxy and M31. We compare the results to the relative galactic habitable zones found with `classical' (independent ring) models, where no gas inflows were included. For both the Milky Way and Andromeda, the main effect of the gas radial inflows is to enhance the number of stars hosting a habitable planet with respect to the `classical' model results, in the region of maximum probability for this occurrence, relative to the classical model results. These results are obtained by taking into account the supernova destruction processes. In particular, we find that in the Milky Way the maximum number of stars hosting habitable planets is at 8 kpc from the Galactic Centre, and the model with radial flows predicts a number which is 38 per cent larger than what was predicted by the classical model. For Andromeda we find that the maximum number of stars with habitable planets is at 16 kpc from the centre and that in the case of radial flows this number is larger by 10 per cent relative to the stars predicted by the classical model.

  1. The origins of radial fracture systems and associated large lava flows on Venus

    NASA Technical Reports Server (NTRS)

    Parfitt, Elisabeth A.; Wilson, Lionel; Head, James W., III

    1992-01-01

    Magellan images have revealed the existence of systems of radial fractures on venus that are very similar in form to terrestrial dike swarms such as the Mackenzie swarm in Northern Canada. The association of many of the fracture systems with lava flows, calderas, and volcanic edifices further support the idea of a dike emplacement origin. A global survey of the Magellan images has allowed the location of 300 such fracture systems. Two types of fracture systems are defined. A series of models were developed to simulate the emplacement of dikes on Venus. Observations of fracture lengths and widths were then used to constrain the emplacement conditions. The model results show that the great length and relatively large width of the fractures can only be explained if the dikes that produce them were emplaced in high driving pressure (pressure buffered) conditions. Such conditions imply high rates of melt production, which is consistent with the melt being derived directly from a plume head. We have recently modeled the vertical emplacement of a dike from the top of a mantle plume and calculated the eruption rates such a dike would produce on reaching the surface. This modeling shows that eruption rates of approximately 0.1 cu km/hr can readily be generated by such a dike, consistent with the above results. However, the sensitivity of the model to dike width and therefore driving pressure means that eruption rates from dikes emplaced from the base of the crust or the head of a mantle plume could be orders of magnitude higher than this. Clearly, therefore, the model needs to be refined in order to better constrain eruption conditions. However, it is worth noting here that the initial results do show that even for moderate dike widths, eruption rates could be at least on the order of those estimated for terrestrial flood basalts.

  2. Aerothermal investigations of mixing flow phenomena in case of radially inclined ejection holes at the leading edge

    SciTech Connect

    Bohn, D.E.; Kusterer, K.A.

    2000-04-01

    A leading edge cooling configuration is investigated numerically by application of a three-dimensional conjugate fluid flow and heat transfer solver, CHT-flow. The code has been developed at the Institute of Steam and Gas Turbines, Aachen University of Technology. It works on the basis of an implicit finite volume method combined with a multi-block technique. The cooling configuration is an axial turbine blade cascade with leading edge ejection through two rows of cooling holes. The rows are located in the vicinity of the stagnation line, one row on the suction side, the other row is on the pressure side. the cooling holes have a radial ejection angle of 45 degrees. This configuration has been investigated experimentally by other authors and the results have been documented as a test case for numerical calculations of ejection flow phenomena. The numerical investigations focus on the aerothermal mixing process in the cooling jets and the impact on the temperature distribution on the blade surface. The radial ejection angles lead to a fully three-dimensional and asymmetric jet flow field. Within a secondary flow analysis, the cooling fluid jets are investigated in detail. The secondary flow fields include asymmetric kidney vortex systems with one dominating vortex on the back side of the jets. The numerical and experimental data show a respectable agreement concerning the vortex development.

  3. Viscous Fingering Induced Flow Instability in Multidimensional Liquid Chromatography

    SciTech Connect

    Mayfield, Kirsty; Shalliker, R. Andrew; Catchpoole, Heather J.; Sweeney, Alan P.; Wong, Victor; Guiochon, Georges A

    2005-07-01

    Viscous fingering is a flow instability phenomenon that results in the destabilisation of the interface between two fluids of differing viscosities. The destabilised interface results in a complex mixing of the two fluids in a pattern that resembles fingers. The conditions that enhance this type of flow instability can be found in coupled chromatographic separation systems, even when the solvents used in each of the separation stages have seemingly similar chemical and physical properties (other than viscosity). For example, the viscosities of acetonitrile and methanol are sufficiently different that instability at the interface between these two solvents can be established and viscous fingering results. In coupled chromatographic systems, the volume of solvent transported from one separation dimension to the second often exceeds the injection volume by two or more orders of magnitude. As a consequence, viscous fingering may occur, when otherwise following the injection of normal analytical size injection plugs viscous fingering would not occur. The findings in this study illustrate the onset of viscous fingering in emulated coupled chromatographic systems and show the importance of correct solvent selection for optimum separation performance.

  4. Theoretical comparison of the performance of gradient elution chromatography at constant pressure and constant flow rate.

    PubMed

    Gritti, Fabrice; Guiochon, Georges

    2012-08-31

    The theory of gradient elution usually assumes a constant flow rate. This works extends it to gradients performed under constant pressure drop and variable flow rates. The peak capacity is derived under both constant flow rate and constant pressure gradient chromatography by integrating the rate of increase of the peak capacity from the hold-up time to the end of the gradient time. Assuming that the eluent mixture is incompressible, the chromatographic system isothermal, the pressure has no effect on the retention pattern, and neglecting the contributions of the instrument to the total pressure drop and the total peak width, it is found that both modes of gradient elution chromatography are strictly equivalent, provided that the elution time of the last eluted compound and the volume gradient are kept the same in both cases. PMID:22818736

  5. Alternative plugs flow liquid chromatography (APFLC)/EI-MS system using a T-shaped flow path.

    PubMed

    Tanikawa, Isao; Konuma, Miwako; Hosono, Hiroko; Nakamura, Hiroshi

    2011-01-01

    The vapor condensation method can be used for forming an alternative flow of liquid masses using a single solvent for alternative plugs flow liquid chromatography (APFLC), described in our previous paper. APFLC is more effective when adopting a T-shaped flow path and aqueous-organic solvents with a liquid-to-gas volume ratio (bulk fraction; ?) ranging between 0.0006 and 0.004 in an open tubular GC capillary column at below 70C. High-density plugs flow by a T-shaped flow path leads to extremely high resolution. Alternative plugs flow is formed when the liquid contact angle to the solid phase is above 75. An aqueous mixture of the usual HPLC solvent can be readily used for APFLC. An EI-mass spectrum is obtained that is comparable with that in the NIST library, except for the DMF mixture medium. Due to low-pressure loss properties in the column, the system does not require a high-pressure liquid pump. Solid hydrocarbon resin with a contact angle to water of between 75 and 79, such as polystyrene and olefinic polymers, is anticipated to be applicable to APFLC and hydro-membrane gas chromatography (HMGC) by a consideration of their surface tensions. PMID:21233568

  6. Results from Evaluation of Representative ASME AG-1 Section FK Radial Flow Dimple Pleated HEPA Filters Under Elevated Conditions - 12002

    SciTech Connect

    Giffin, Paxton K.; Parsons, Michael S.; Rickert, Jaime G.; Waggoner, Charles A.

    2012-07-01

    The American Society of Mechanical Engineers (ASME) has recently added Section FK establishing requirements for radial flow HEPA filters to the Code on Nuclear Air and Gas Treatment (AG-1). Section FK filters are expected to be a major element in the HEPA filtration systems across the US Department of Energy (DOE) complex. Radial flow filters have been used in Europe for some time, however a limited amount of performance evaluation data exists with respect to these new AG-1 Section FK units. In consultation with a technical working group, the Institute for Clean Energy Technology (ICET) at Mississippi State University (MSU)has evaluated a series of representative AG-1 Section FK dimple pleated radial flow HEPA filters. The effects of elevated relative humidity and temperature conditions on these filters are particularly concerning. Results from the evaluation of Section FK filters under ambient conditions have been presented at the 2011 waste management conference. Additions to the previous test stand to enable high temperature and high humidity testing, a review of the equipment used, the steps taken to characterize the new additions, and the filter test results are presented in this study. Test filters were evaluated at a volumetric flow rate of 56.6 m{sup 3}/min (2000 cfm) and were challenged under ambient conditions with Alumina, Al(OH){sub 3}, until reaching a differential pressure of 1 kPa (4 in. w.c.), at which time the filters were tested, unchallenged with aerosol, at 54 deg. C (130 deg. F) for approximately 1 hour. At the end of that hour water was sprayed near the heat source to maximize vaporization exposing the filter to an elevated relative humidity up to 95%. Collected data include differential pressure, temperature, relative humidity, and volumetric flow rate versus time. (authors)

  7. A Galerkin finite-element flow model to predict the transient response of a radially symmetric aquifer

    USGS Publications Warehouse

    Reilly, Thomas E.

    1984-01-01

    A computer program developed to evaluate radial flow of ground water, such as at a pumping well, recharge basin, or injection well, is capable of simulating anisotropic, inhomogenous, confined, or pseudo-unconfined (constant saturated thickness) conditions. Results compare well with those calculated from published analytical and model solutions. The program is based on the Galerkin finite-element technique. A sample model run is presented to illustrate the use of the program; supplementary material provides the program listing as well as a sample problem data set and output. From the text and other material presented, one can use the program to predict drawdowns from pumping and ground-water buildups from recharge in a radially symmetric ground-water system.

  8. Centrifugal instability and turbulence development in Taylor-Couette flow with forced radial throughflow of high intensity

    NASA Astrophysics Data System (ADS)

    Mochalin, Ievgen V.; Khalatov, Artem A.

    2015-09-01

    A numerical simulation of the turbulent flow between coaxial permeable cylinders is performed for the case of the rotating inner cylinder and superimposed radial flow through the annular domain. Both forced inflow and outflow are considered in a wide range of the rotation rate and throughflow intensity. Two configurations of the rotating cylinder are examined with an entire permeable porous surface and with lengthwise porous slots. The stable rotational fluid motion is shown to be concentrated within a boundary layer close to the inner cylinder surface at strong enough imposed radial inflow. Under such conditions, the centrifugal stability boundary is independent on the gap width. Flow stabilization due to the forced inflow is possible at any rotation rate considered for both the configurations of the inner rotating cylinder. The stabilization by the forced outflow is feasible only in the case of the entire permeable rotating cylinder. But there are always large-scale vortices in the gap under conditions of the forced outflow through the slotted rotating cylinder except for the relatively low rotation rate. Transition to turbulence in the boundary layer at the inner rotating cylinder may occur before the centrifugal instability onset at large enough inflow intensity. The boundary layer thickness and turbulence intensity are influenced by the inflow rate and differ between the cases of the entire permeable cylinder and the slotted one.

  9. Onset of radial flow in p+p collisions

    SciTech Connect

    Jiang, Kun; Zhu, Yinying; Liu, Weitao; Chen, Hongfang; Li, Cheng; Ruan, Lijuan; Tang, Zebo; Xu, Zhangbu

    2015-02-23

    It has been debated for decades whether hadrons emerging from p+p collisions exhibit collective expansion. The signal of the collective motion in p+p collisions is not as clear as in heavy-ion collisions because of the low multiplicity and large fluctuation in p+p collisions. Tsallis Blast-Wave (TBW) model is a thermodynamic approach, introduced to handle the overwhelming correlation and fluctuation in the hadronic processes. We have systematically studied the identified particle spectra in p+p collisions from RHIC to LHC using TBW and found no appreciable radial flow in p+p collisions below √s = 900 GeV. At LHC higher energy of 7 TeV in p+p collisions, the radial flow velocity achieves an average of (β) = 0.320 ± 0.005. This flow velocity is comparable to that in peripheral (40-60%) Au+Au collisions at RHIC. In addition, breaking of the identified particle spectra mT scaling was also observed at LHC from a model independent test.

  10. A design methodology for a magnetorheological fluid damper based on a multi-stage radial flow mode

    NASA Astrophysics Data System (ADS)

    Liao, C. R.; Zhao, D. X.; Xie, L.; Liu, Q.

    2012-08-01

    In this paper, a magnetorheological (MR) fluid damper based on a multi-stage radial flow mode is put forward, compared with traditional ones with annular damping channel which are of low magnetic field utilization and high energy consumption. The equivalent magnetic circuit model is derived, along with the relation between the magnetic induction at the working gap and the exciting current in the field coils. The finite-element software ANYSY is used to analyze the distribution of the magnetic field in the MR valve. The flow differential equation for a MR fluid in radial flow is theoretically set up, and the numerical solution is validated by means of the Herschel-Bulkley constitutive model. A MR damper was designed and fabricated in Chongqing University in accordance with the technical requirements of a railway vehicle anti-yaw damper, and the force-displacement characteristic of the damper was tested with J95-I type shock absorber test-bed. The results show that the experimental damping forces are in good agreement with the analytical ones, and the methodology is believed to help predict the damping force of a MR damper.

  11. Onset of radial flow in p+p collisions

    SciTech Connect

    Jiang, Kun; Zhu, Yinying; Liu, Weitao; Chen, Hongfang; Li, Cheng; Ruan, Lijuan; Tang, Zebo; Xu, Zhangbu

    2015-02-23

    It has been debated for decades whether hadrons emerging from p+p collisions exhibit collective expansion. The signal of the collective motion in p+p collisions is not as clear as in heavy-ion collisions because of the low multiplicity and large fluctuation in p+p collisions. Tsallis Blast-Wave (TBW) model is a thermodynamic approach, introduced to handle the overwhelming correlation and fluctuation in the hadronic processes. We have systematically studied the identified particle spectra in p+p collisions from RHIC to LHC using TBW and found no appreciable radial flow in p+p collisions below ?s = 900 GeV. At LHC higher energy of 7 TeV in p+p collisions, the radial flow velocity achieves an average of (?) = 0.320 0.005. This flow velocity is comparable to that in peripheral (40-60%) Au+Au collisions at RHIC. In addition, breaking of the identified particle spectra mT scaling was also observed at LHC from a model independent test.

  12. E × B flow shear effects on radial correlation length of turbulence and gyroradius scaling of confinement

    NASA Astrophysics Data System (ADS)

    Hahm, T. S.; Burrell, K. H.

    1996-01-01

    The radial correlation length of the turbulence responsible for transport can have a different gyroradius scaling in low (L)-mode and high (H)-mode plasmas due to E×B flow shear effects, as predicted by the two-point nonlinear analysis in general tokamak geometry [Phys. Plasmas 2, 1648 (1995)]. This difference offers a possible understanding of the recent ρ*-scan experiment results on DIII-D [Fusion Technol. 8, 441 (1985)] L-mode and H-mode plasmas [Phys. Plasmas 2, 2342 (1995)]. Within our model, thermal diffusivity in H-mode plasmas scales like gyro-Bohm, independent of the scaling in L-mode plasmas.

  13. Final Technical Report: Numerical and Experimental Investigation of Turbulent Transport Control via Shaping of Radial Plasma Flow Profiles

    SciTech Connect

    Schuster, Eugenio

    2014-05-02

    The strong coupling between the different physical variables involved in the plasma transport phenomenon and the high complexity of its dynamics call for a model-based, multivariable approach to profile control where those predictive models could be exploited. The overall objective of this project has been to extend the existing body of work by investigating numerically and experimentally active control of unstable fluctuations, including fully developed turbulence and the associated cross-field particle transport, via manipulation of flow profiles in a magnetized laboratory plasma device. Fluctuations and particle transport can be monitored by an array of electrostatic probes, and Ex#2;B flow profiles can be controlled via a set of biased concentric ring electrodes that terminate the plasma column. The goals of the proposed research have been threefold: i- to develop a predictive code to simulate plasma transport in the linear HELCAT (HELicon-CAThode) plasma device at the University of New Mexico (UNM), where the experimental component of the proposed research has been carried out; ii- to establish the feasibility of using advanced model-based control algorithms to control cross-field turbulence-driven particle transport through appropriate manipulation of radial plasma flow profiles, iii- to investigate the fundamental nonlinear dynamics of turbulence and transport physics. Lehigh University (LU), including Prof. Eugenio Schuster and one full-time graduate student, has been primarily responsible for control-oriented modeling and model-based control design. Undergraduate students have also participated in this project through the National Science Foundation Research Experience for Undergraduate (REU) program. The main goal of the LU Plasma Control Group has been to study the feasibility of controlling turbulence-driven transport by shaping the radial poloidal flow profile (i.e., by controlling flow shear) via biased concentric ring electrodes.

  14. Particle simulations of divergent and convergent radial electron flows in cylindrical Pierce diodes

    SciTech Connect

    Alves, M.V.; Gratton, F.T.; Gnavi, G.; Moreno, C.H.

    1997-08-01

    A special class of Pierce diodes, that consists of a pair of grounded coaxial cylindrical electrodes, with electrons streaming radially between them, is studied. The full set of roots of the dispersion relation of the Pierce instability is obtained by solving the dispersion relation numerically. The nonlinear behaviour of the system is then investigated using particle simulation. It is shown that the behaviour of cylindrical systems depends on two nondimensional parameters. Linear and nonlinear properties are different for convergent and divergent configurations. Several remarkable differences between cylindrical and planar Pierce diodes are reported. {copyright} {ital 1997 American Institute of Physics.}

  15. Integrated horizontal-flow anaerobic and radial-flow aerobic reactors for the removal of organic matter and nitrogen from domestic sewage.

    PubMed

    Vieira, L G T; Fazolo, A; Zaiat, M; Foresti, E

    2003-01-01

    This paper presents the conception and discusses the results obtained from the operation of an integrated biological anaerobic/aerobic/anaerobic system composed of horizontal-flow anaerobic and radial-flow aerobic reactors for domestic sewage treatment. The performance of a horizontal-flow anaerobic immobilized biomass reactor, with five stages,followed by a radial-flow aerobic immobilized biomass reactor was evaluated along 22 weeks. After the 14th week, the last stage of the HAIB reactor was used as a denitrifying unit. Polyurethane foam cubic matrices with 1-cm sides were used as support for biomass immobilization in all the units. The influent domestic sewage presented mean chemical oxygen demand of 365 +/- 71 mg. 1(-1) and the temperature was 23 +/- 3degrees C. The integrated system achieved COD removal efficiency of 90% while the maximum ammonium removal efficiency was 97% in the aerobic post-treatment unit. The nitrification process was found to be better represented by first-order reactions in series model. The apparent first-order kinetic coefficient for nitrate formation was about 50 times higher than that estimated for the nitrite formation. The denitrification process was well represented by a Monod-type kinetic model. The maximum specific denitrifying rate and the half-saturation coefficient were 2.9 x 10(-4) mg NO(3)(-)-N mg(-1) VSS h(-1) and 19.4 mg NO(3)(-)-N 1(-1), respectively. PMID:12641252

  16. Cylindrically confined pair-ion-electron and pair-ion plasmas having axial sheared flow and radial gradients

    NASA Astrophysics Data System (ADS)

    Batool, Nazia; Saleem, H.

    2013-10-01

    The linear and nonlinear dynamics of pair-ion (PI) and pair-ion-electron plasmas (PIE) have been investigated in a cylindrical geometry with a sheared plasma flow along the axial direction having radial dependence. The coupled linear dispersion relation of low frequency electrostatic waves has been presented taking into account the Guassian profile of density and linear gradient of sheared flow. It is pointed out that the quasi-neutral cold inhomogeneous pure pair ion plasma supports only the obliquely propagating convective cell mode. The linear dispersion relation of this mode has been solved using boundary conditions. The nonlinear structures in the form of vortices formed by different waves have been discussed in PI and PIE plasmas.

  17. Cylindrically confined pair-ion-electron and pair-ion plasmas having axial sheared flow and radial gradients

    SciTech Connect

    Batool, Nazia; Saleem, H.

    2013-10-15

    The linear and nonlinear dynamics of pair-ion (PI) and pair-ion-electron plasmas (PIE) have been investigated in a cylindrical geometry with a sheared plasma flow along the axial direction having radial dependence. The coupled linear dispersion relation of low frequency electrostatic waves has been presented taking into account the Guassian profile of density and linear gradient of sheared flow. It is pointed out that the quasi-neutral cold inhomogeneous pure pair ion plasma supports only the obliquely propagating convective cell mode. The linear dispersion relation of this mode has been solved using boundary conditions. The nonlinear structures in the form of vortices formed by different waves have been discussed in PI and PIE plasmas.

  18. A Radial Flow Microfluidic Device for Ultra-high-throughput Affinity-based Isolation of Circulating Tumor Cells

    PubMed Central

    Murlidhar, Vasudha; Zeinali, Mina; Grabauskiene, Svetlana; Ghannad-Rezaie, Mostafa; Wicha, Max S.; Simeone, Diane M.; Ramnath, Nithya; Reddy, Rishindra M.

    2015-01-01

    Circulating tumor cells (CTCs) are believed to play an important role in metastasis, a process responsible for the majority of cancer-related deaths. But their rarity in the bloodstream makes microfluidic isolation complex and time-consuming. Additionally the low processing speeds can be a hindrance to obtaining higher yields of CTCs, limiting their potential use as biomarkers for early diagnosis. Here we report a high throughput microfluidic technology, the OncoBean Chip, employing radial flow that introduces a varying shear profile across the device enabling efficient cell capture by affinity at high flow rates. The recovery from whole blood was validated with cancer cell lines H1650 and MCF7, achieving a mean efficiency >80% at a throughput of 10 mL hr?1 in contrast to a flow rate of 1 mL hr?1 standardly reported with other microfluidic devices. Cells were recovered with a viability rate of 93% at these high speeds, increasing the ability to use captured CTCs for downstream analysis. Broad clinical application was demonstrated using comparable flow rates from blood specimens obtained from breast, pancreatic and lung cancer patients. Comparable CTC numbers were recovered in all the samples at the two flow rates demonstrating the ability of the technology to perform at high-throughputs. PMID:25074448

  19. Universality Results for Multi-layer Radial Hele-Shaw Flows

    NASA Astrophysics Data System (ADS)

    Daripa, Prabir; Gin, Craig; Daripa Research Team

    2014-03-01

    Saffman-Taylor instability is a well known viscosity driven instability of an interface separating two immiscible fluids. We study linear stability of this displacement process in multi-layer radial Hele-Shaw geometry involving an arbitrary number of immiscible fluid phases. Universal stability results have been obtained and applied to design displacement processes that are considerably less unstable than the pure Saffman-Taylor case. In particular, we derive universal formula which gives specific values of the viscosities of the fluid layers corresponding to smallest unstable band. Other similar universal results will also be presented. The talk is based on ongoing work. Supported by an NPRP Grant # 08-777-1-141 from the Qatar National Research Fund (a member of the Qatar Foundation). The statements made herein are solely the responsibility of the authors.

  20. Use of greatly-reduced gas flows in flow-modulated comprehensive two-dimensional gas chromatography-mass spectrometry.

    PubMed

    Tranchida, Peter Q; Franchina, Flavio A; Dugo, Paola; Mondello, Luigi

    2014-09-12

    The present research is specifically based on the use of greatly-reduced gas flows, in flow-modulator (FM) comprehensive two-dimensional gas chromatography systems. In particular, focus of the present research is directed to FM devices characterized by an accumulation stage, and a much briefer re-injection step. It has been widely accepted that the operation of such FM systems requires high gas flows (?20mL/min), to re-inject the gas-phase contents of sample (or accumulation) loops, onto the second column. On the contrary, it will be herein demonstrated that much lower gas flows (? 6-8mL/min) can efficiently perform the modulation step of re-injection. The possibility of using such improved operational conditions is given simply by a fine optimization of the processes of accumulation and re-injection. The application of lower gas flows not only means that second-dimension separations are carried out under better analytical conditions, but, even more importantly, greatly reduces problems which arise when using mass spectrometry (i.e., sensitivity and instrumental pumping capacity). PMID:25108766

  1. Presentation of the MERC work-flow for the computation of a 2D radial reflector in a PWR

    SciTech Connect

    Clerc, T.; Hebert, A.; Leroyer, H.; Argaud, J. P.; Poncot, A.; Bouriquet, B.

    2013-07-01

    This paper presents a work-flow for computing an equivalent 2D radial reflector in a pressurized water reactor (PWR) core, in adequacy with a reference power distribution, computed with the method of characteristics (MOC) of the lattice code APOLLO2. The Multi-modelling Equivalent Reflector Computation (MERC) work-flow is a coherent association of the lattice code APOLLO2 and the core code COCAGNE, structured around the ADAO (Assimilation de Donnees et Aide a l'Optimisation) module of the SALOME platform, based on the data assimilation theory. This study leads to the computation of equivalent few-groups reflectors, that can be spatially heterogeneous, which have been compared to those obtained with the OPTEX similar methodology developed with the core code DONJON, as a first validation step. Subsequently, the MERC work-flow is used to compute the most accurate reflector in consistency with all the R and D choices made at Electricite de France (EDF) for the core modelling, in terms of number of energy groups and simplified transport solvers. We observe important reductions of the power discrepancies distribution over the core when using equivalent reflectors obtained with the MERC work-flow. (authors)

  2. Simultaneous effects of radial magnetic field and wall properties on peristaltic flow of Carreau-Yasuda fluid in curved flow configuration

    NASA Astrophysics Data System (ADS)

    Hayat, T.; Tanveer, A.; Alsaadi, F.

    2015-12-01

    The objective of present article is to address the magnetohydrodynamic (MHD) peristaltic flow of Carreau-Yasuda fluid in a curved geometry. The channel boundaries satisfy wall slip and compliant properties. The fluid is electrically conducting through an applied magnetic field in the radial direction. Heat transfer is also studied. Governing equation comprised the viscous dissipation effects. The non-linear expressions are first obtained and then approximated using long wavelength and low Reynolds number considerations. The resulting systems are solved for the series solutions. The expressions of velocity, temperature, heat transfer coefficient and stream function are obtained and analyzed via graphical illustrations.

  3. An experimental and computational investigation of flow in a radial inlet of an industrial pipeline centrifugal compressor

    SciTech Connect

    Flathers, M.B.; Bache, G.E.; Rainsberger, R.

    1996-04-01

    The flow field of a complex three-dimensional radial inlet for an industrial pipeline centrifugal compressor has been experimentally determined on a half-scale model. Based on the experimental results, inlet guide vanes have been designed to correct pressure and swirl angle distribution deficiencies. The unvaned and vaned inlets are analyzed with a commercially available fully three-dimensional viscous Navier-Stokes code. Since experimental results were available prior to the numerical study, the unvaned analysis is considered a postdiction while the vaned analysis is considered a prediction. The computational results of the unvaned inlet have been compared to the previously obtained experimental results. The experimental method utilized for the unvaned inlet is repeated for the vaned inlet and the data have been used to verify the computational results. The paper will discuss experimental, design, and computational procedures, grid generation, boundary conditions, and experimental versus computational methods. Agreement between experimental and computational results is very good, both in prediction and postdiction modes. The results of this investigation indicate that CFD offers a measurable advantage in design, schedule, and cost and can be applied to complex, three-dimensional radial inlets.

  4. Distributed control of reactive power flow in a radial distribution circuit with high photovoltaic penetration

    SciTech Connect

    Chertkov, Michael; Turitsyn, Konstantin; Backhaus, Scott; Sule, Petr

    2009-01-01

    We show how distributed control of reactive power can serve to regulate voltage and minimize resistive losses in a distribution circuit that includes a significant level of photovoltaic (PV) generation. To demonstrate the technique, we consider a radial distribution circuit with a single branch consisting of sequentially-arranged residential-scale loads that consume both real and reactive power. In parallel, some loads also have PV generation capability. We postulate that the inverters associated with each PV system are also capable of limited reactive power generation or consumption, and we seek to find the optimal dispatch of each inverter's reactive power to both maintain the voltage within an acceptable range and minimize the resistive losses over the entire circuit. We assume the complex impedance of the distribution circuit links and the instantaneous load and PV generation at each load are known. We compare the results of the optimal dispatch with a suboptimal local scheme that does not require any communication. On our model distribution circuit, we illustrate the feasibility of high levels of PV penetration and a significant (20% or higher) reduction in losses.

  5. Mixing characteristics of mixers in flow analysis. Application to two-dimensional detection in ion chromatography.

    PubMed

    Liao, Hongzhu; Dasgupta, Purnendu K; Srinivasan, Kannan; Liu, Yan

    2015-01-01

    Three mixer designs, a back-flow tee mixer (BT), an end-blocked membrane tee mixer (EMT), and a tubular membrane mixer (TM), were fabricated and compared to three commercially available mixers, Visco-Jet Micro mixer (VJM) and HS binary tee mixer with 2 and 10 ?L volume (HS-2 and HS-10) mixing cartridges. Internal volumes ranged from 8.3 to 20.3 ?L. Performance characteristics were evaluated by the Villermaux-Dushman reaction, noise in baseline conductance upon mixing an electrolyte solution with water, and dispersion/relative dispersion of an injected solute. No single characteristic would uniquely qualify a particular device. In typical postcolumn use when a small reagent flow is added to a principal flow stream using a low-pulsation high-end chromatographic pump, with the worst of these mixers, imperfect mixing accounted for 99.6% of the observed noise. EMT, BT, and TM with asymmetric inlets provided better mixing performances relative to VJM, HS-2, and HS-10 with symmetric inlet ports, especially when the secondary liquid flow rate was much lower than the principal stream-flow rate. Dispersion per unit residence time was singularly large for HS-2. Based on its mixing efficiency and small dispersion, the BT design was found to be the best for practicing postcolumn reaction. As an illustrative application, this was then used to introduce electrogenerated LiOH in a suppressed ion chromatography system to perform sensitive detection of weak acids in a second dimension. PMID:25426864

  6. E{times}B flow shear effects on radial correlation length of turbulence and gyroradius scaling of confinement

    SciTech Connect

    Hahm, T.S.; Burrell, K.H.

    1996-01-01

    The radial correlation length of the turbulence responsible for transport can have a different gyroradius scaling in low (L)-mode and high (H)-mode plasmas due to {bold E{times}B} flow shear effects, as predicted by the two-point nonlinear analysis in general tokamak geometry [Phys. Plasmas {bold 2}, 1648 (1995)]. This difference offers a possible understanding of the recent {rho}{sub {asterisk}}-scan experiment results on DIII-D [Fusion Technol. {bold 8}, 441 (1985)] L-mode and H-mode plasmas [Phys. Plasmas {bold 2}, 2342 (1995)]. Within our model, thermal diffusivity in H-mode plasmas scales like gyro-Bohm, independent of the scaling in L-mode plasmas. {copyright} {ital 1996 American Institute of Physics.}

  7. Approximate analysis of three-dimensional groundwater flow toward a radial collector well in a finite-extent unconfined aquifer

    NASA Astrophysics Data System (ADS)

    Huang, C.-S.; Chen, J.-J.; Yeh, H.-D.

    2016-01-01

    This study develops a three-dimensional (3-D) mathematical model for describing transient hydraulic head distributions due to pumping at a radial collector well (RCW) in a rectangular confined or unconfined aquifer bounded by two parallel streams and no-flow boundaries. The streams with low-permeability streambeds fully penetrate the aquifer. The governing equation with a point-sink term is employed. A first-order free surface equation delineating the water table decline induced by the well is considered. Robin boundary conditions are adopted to describe fluxes across the streambeds. The head solution for the point sink is derived by applying the methods of finite integral transform and Laplace transform. The head solution for a RCW is obtained by integrating the point-sink solution along the laterals of the RCW and then dividing the integration result by the sum of lateral lengths. On the basis of Darcy's law and head distributions along the streams, the solution for the stream depletion rate (SDR) can also be developed. With the aid of the head and SDR solutions, the sensitivity analysis can then be performed to explore the response of the hydraulic head to the change in a specific parameter such as the horizontal and vertical hydraulic conductivities, streambed permeability, specific storage, specific yield, lateral length, and well depth. Spatial head distributions subject to the anisotropy of aquifer hydraulic conductivities are analyzed. A quantitative criterion is provided to identify whether groundwater flow at a specific region is 3-D or 2-D without the vertical component. In addition, another criterion is also given to allow for the neglect of vertical flow effect on SDR. Conventional 2-D flow models can be used to provide accurate head and SDR predictions if satisfying these two criteria.

  8. Analysis of three-dimensional groundwater flow toward a radial collector well in a finite-extent unconfined aquifer

    NASA Astrophysics Data System (ADS)

    Huang, C.-S.; Chen, J.-J.; Yeh, H.-D.

    2015-08-01

    This study develops a three-dimensional mathematical model for describing transient hydraulic head distributions due to pumping at a radial collector well (RCW) in a rectangular confined or unconfined aquifer bounded by two parallel streams and no-flow boundaries. The governing equation with a point-sink term is employed. A first-order free surface equation delineating the water table decline induced by the well is considered. The head solution for the point sink is derived by applying the methods of double-integral transform and Laplace transform. The head solution for a RCW is obtained by integrating the point-sink solution along the laterals of the RCW and then dividing the integration result by the sum of lateral lengths. On the basis of Darcy's law and head distributions along the streams, the solution for the stream depletion rate (SDR) can also be developed. With the aid of the head and SDR solutions, the sensitivity analysis can then be performed to explore the response of the hydraulic head to the change in a specific parameter such as the horizontal and vertical hydraulic conductivities, streambed permeability, specific storage, specific yield, lateral length and well depth. Spatial head distributions subject to the anisotropy of aquifer hydraulic conductivities are analyzed. A quantitative criterion is provided to identify whether groundwater flow at a specific region is 3-D or 2-D without the vertical component. In addition, another criterion is also given to allow the neglect of vertical flow effect on SDR. Conventional 2-D flow models can be used to provide accurate head and SDR predictions if satisfying these two criteria.

  9. A flow-through chromatography process for influenza A and B virus purification.

    PubMed

    Weigel, Thomas; Solomaier, Thomas; Peuker, Alessa; Pathapati, Trinath; Wolff, Michael W; Reichl, Udo

    2014-10-01

    Vaccination is still the most efficient measure to protect against influenza virus infections. Besides the seasonal wave of influenza, pandemic outbreaks of bird or swine flu represent a high threat to human population. With the establishment of cell culture-based processes, there is a growing demand for robust, economic and efficient downstream processes for influenza virus purification. This study focused on the development of an economic flow-through chromatographic process avoiding virus strain sensitive capture steps. Therefore, a three-step process consisting of anion exchange chromatography (AEC), Benzonase(®) treatment, and size exclusion chromatography with a ligand-activated core (LCC) was established, and tested for purification of two influenza A virus strains and one influenza B virus strain. The process resulted in high virus yields (≥68%) with protein contamination levels fulfilling requirements of the European Pharmacopeia for production of influenza vaccines for human use. DNA was depleted by ≥98.7% for all strains. The measured DNA concentrations per dose were close to the required limits of 10ng DNA per dose set by the European Pharmacopeia. In addition, the added Benzonase(®) could be successfully removed from the product fraction. Overall, the presented downstream process could potentially represent a simple, robust and economic platform technology for production of cell culture-derived influenza vaccines. PMID:24992667

  10. Radial diffusion and penetration of gas molecules and aerosol particles through laminar flow reactors, denuders, and sampling tubes.

    PubMed

    Knopf, Daniel A; Pschl, Ulrich; Shiraiwa, Manabu

    2015-04-01

    Flow reactors, denuders, and sampling tubes are essential tools for many applications in analytical and physical chemistry and engineering. We derive a new method for determining radial diffusion effects and the penetration or transmission of gas molecules and aerosol particles through cylindrical tubes under laminar flow conditions using explicit analytical equations. In contrast to the traditional Brown method [Brown, R. L. J. Res. Natl. Bur. Stand. (U. S.) 1978, 83, 1-8] and CKD method (Cooney, D. O.; Kim, S. S.; Davis, E. J. Chem. Eng. Sci. 1974, 29, 1731-1738), the new approximation developed in this study (known as the KPS method) does not require interpolation or numerical techniques. The KPS method agrees well with the CKD method under all experimental conditions and also with the Brown method at low Sherwood numbers. At high Sherwood numbers corresponding to high uptake on the wall, flow entry effects become relevant and are considered in the KPS and CKD methods but not in the Brown method. The practical applicability of the KPS method is demonstrated by analysis of measurement data from experimental studies of rapid OH, intermediate NO3, and slow O3 uptake on various organic substrates. The KPS method also allows determination of the penetration of aerosol particles through a tube, using a single equation to cover both the limiting cases of high and low deposition described by Gormley and Kennedy (Proc. R. Ir. Acad., Sect. A. 1949, 52A, 163-169). We demonstrate that the treatment of gas and particle diffusion converges in the KPS method, thus facilitating prediction of diffusional loss and penetration of gases and particles, analysis of chemical kinetics data, and design of fluid reactors, denuders, and sampling lines. PMID:25744622

  11. Continuous flow ion mobility separation with mass spectrometric detection using a nano-radial differential mobility analyzer at low flow rates.

    PubMed

    Brunelli, N A; Neidholdt, E L; Giapis, K P; Flagan, R C; Beauchamp, J L

    2013-05-01

    We describe a hybrid mass-mobility instrument in which a continuous-flow ion mobility classifier is used as a front-end separation device for mass spectrometric analysis of ions generated with an electrospray ionization source. Using nitrogen as a carrier gas, the resolving power of the nano-radial differential mobility analyzer (nRDMA) for nanometer-sized ions is 5-7 for tetraalkylammonium ions. Data are presented demonstrating the ability of the system to resolve the different aggregation and charge states of tetraalkylammonium ions and protonated peptides using a quadrupole ion trap (QIT) mass spectrometer to analyze the mobility-classified ions. Specifically, data are presented for the two charge states of the decapeptide Gramicidin S. A key feature of the new instrument is the ability to continuously transmit ions with specific mobilities to the mass spectrometer for manipulation and analysis. PMID:23544674

  12. Modeling of Tsunami Equations and Atmospheric Swirling Flows with a Graphics Processing Unit (GPU) and Radial Basis Functions (RBF)

    NASA Astrophysics Data System (ADS)

    Schmidt, J.; Piret, C.; Zhang, N.; Kadlec, B. J.; Liu, Y.; Yuen, D. A.; Wright, G. B.; Sevre, E. O.

    2008-12-01

    The faster growth curves in the speed of GPUs relative to CPUs in recent years and its rapidly gained popularity has spawned a new area of development in computational technology. There is much potential in utilizing GPUs for solving evolutionary partial differential equations and producing the attendant visualization. We are concerned with modeling tsunami waves, where computational time is of extreme essence, for broadcasting warnings. In order to test the efficacy of the GPU on the set of shallow-water equations, we employed the NVIDIA board 8600M GT on a MacBook Pro. We have compared the relative speeds between the CPU and the GPU on a single processor for two types of spatial discretization based on second-order finite-differences and radial basis functions. RBFs are a more novel method based on a gridless and a multi- scale, adaptive framework. Using the NVIDIA 8600M GT, we received a speed up factor of 8 in favor of GPU for the finite-difference method and a factor of 7 for the RBF scheme. We have also studied the atmospheric dynamics problem of swirling flows over a spherical surface and found a speed-up of 5.3 using the GPU. The time steps employed for the RBF method are larger than those used in finite-differences, because of the much fewer number of nodal points needed by RBF. Thus, in modeling the same physical time, RBF acting in concert with GPU would be the fastest way to go.

  13. A novel micropreconcentrator employing a laminar flow patterned heater for micro gas chromatography

    NASA Astrophysics Data System (ADS)

    Tian, W.-C.; Wu, T. H.; Lu, C.-J.; Chen, W. R.; Sheen, H. J.

    2012-06-01

    A simple micromachined process based on one photomask is developed for a novel micropreconcentrator (PCT) used in a micro gas chromatograph (GC). Unique thick silver heating microstructures with a high surface area for microheater of PCT are fabricated by combining the microfluidic laminar flow technique and the Tollens reaction within a microchannel. Silver deposition using this laminar flow patterning technique provides a higher deposition rate and easier microfabrication compared to conventional micromachined technologies for thick metal microstructures (>200 m). An amorphous and porous carbon film that functions as an adsorbent is grown on microheaters inside the microchannel. The PCT can be heated to >300 C rapidly by applying a constant electrical power of 1 W with a heating rate of 10 C s-1. Four volatile organic compounds, acetone, benzene, toluene and xylene, are collected through the proposed novel PCTs and separated successfully using a 17 m long gas chromatography column. The peak widths at half height (PWHHs) of the four compounds are relatively narrow (<6 s), and the minimum PWHH of 3.75 s is obtained for acetone. The preconcentration factors are >38 000 for benzene and toluene.

  14. Column properties and flow profiles of a flat, wide column for high-pressure liquid chromatography

    SciTech Connect

    Mriziq, Khaled S; Guiochon, Georges A

    2008-01-01

    The design and the construction of a pressurized, flat, wide column for high-performance liquid chromatography (HPLC) are described. This apparatus, which is derived from instruments that implement over-pressured thin layer chromatography, can carry out only uni-dimensional chromatographic separations. However, it is intended to be the first step in the development of more powerful instruments that will be able to carry out two-dimensional chromatographic separations, in which case, the first separation would be a space-based separation, LC{sup x}, taking place along one side of the bed and the second separation would be a time-based separation, LC{sup t}, as in classical HPLC but proceeding along the flat column, not along a tube. The apparatus described consists of a pressurization chamber made of a Plexiglas block and a column chamber made of stainless steel. These two chambers are separated by a thin Mylar membrane. The column chamber is a cavity which is filled with a thick layer (ca. 1 mm) of the stationary phase. Suitable solvent inlet and outlet ports are located on two opposite sides of the sorbent layer. The design allows the preparation of a homogenous sorbent layer suitable to be used as a chromatographic column, the achievement of effective seals of the stationary phase layer against the chamber edges, and the homogenous flow of the mobile phase along the chamber. The entire width of the sorbent layer area can be used to develop separations or elute samples. The reproducible performance of the apparatus is demonstrated by the chromatographic separations of different dyes. This instrument is essentially designed for testing detector arrays to be used in a two-dimensional LC{sup x} x LC{sup t} instrument. The further development of two-dimension separation chromatographs based on the apparatus described is sketched.

  15. Spatial analysis of aquifer response times for radial flow processes: Nondimensional analysis and laboratory-scale tests

    NASA Astrophysics Data System (ADS)

    Jazaei, Farhad; Simpson, Matthew J.; Clement, T. Prabhakar

    2016-01-01

    A fundamental concept in groundwater hydrology is the notion of steady state, or equilibrium conditions. When a system at some initial steady state condition is perturbed by pumping, a transient cone of depression will develop and the system will approach a new steady state condition. Understanding the time scale required for the transient process to occur is of practical interest since it would help practitioners decide whether to use a steady state model or a more complicated transient model. Standard approaches to estimate the response time use simple scaling relationships which neglect spatial variations. Alternatively, others define the response time to be the amount of time taken for the difference between the transient and steady state solutions to fall below some arbitrary tolerance level. Here, we present a novel approach and use the concept of mean action time to predict aquifer response time scales in a two-dimensional radial geometry for pumping, injection and recovery processes. Our approach leads to relatively simple closed form expressions that explicitly show how the time scale depends on the hydraulic parameters and position. Furthermore, our dimensionless framework allows us to predict the response time scales for a range of applications including small scale laboratory problems and large scale field problems. Our analysis shows that the response time scales vary spatially, but are equivalent for pumping, injection and associated recovery processes. Furthermore, the time scale is independent of the pumping or injection flow rate. We test these predictions in a laboratory scale aquifer and find that our physical measurements corroborate the theoretical predictions.

  16. Selective and Sensitive Chemiluminescence Determination of MCPB: Flow Injection and Liquid Chromatography.

    PubMed

    Meseguer-Lloret, Susana; Torres-Cartas, Sagrario; Catalá-Icardo, Mónica; Gómez-Benito, Carmen

    2016-02-01

    Two new chemiluminescence (CL) methods are described for the determination of the herbicide 4-(4-chloro-o-tolyloxy) butyric acid (MCPB). First, a flow injection chemiluminescence (FI-CL) method is proposed. In this method, MCPB is photodegraded with an ultraviolet (UV) lamp and the photoproducts formed provide a great CL signal when they react with ferricyanide in basic medium. Second, a high-performance liquid chromatography chemiluminescence (HPLC-CL) method is proposed. In this method, before the photodegradation and CL reaction, the MCPB and other phenoxyacid herbicides are separated in a C18 column. The experimental conditions for the FI-CL and HPLC-CL methods are optimized. Both methods present good sensitivity, the detection limits being 0.12 µg L(-1) and 0.1 µg L(-1) (for FI-CL and HPLC-CL, respectively) when solid phase extraction (SPE) is applied. Intra- and interday relative standard deviations are below 9.9%. The methods have been satisfactorily applied to the analysis of natural water samples. FI-CL method can be employed for the determination of MCPB in simple water samples and for the screening of complex water samples in a fast, economic, and simple way. The HPLC-CL method is more selective, and allows samples that have not been resolved with the FI-CL method to be solved. PMID:26903566

  17. Microemulsion electrokinetic chromatography in suppressed electroosmotic flow environment. Separation of fat-soluble vitamins.

    PubMed

    Pedersen-Bjergaard, S; Naess, O; Moestue, S; Rasmussen, K E

    2000-04-21

    Microemulsion electrokinetic chromatography (MEEKC) was carried out in a pH 2.5 phosphate buffer to effectively suppress the electroosmotic flow (EOF). With 66.6% (w/w) 25 mM phosphate buffer pH 2.5, 20.0% (w/w) 2-propanol, 6.6% (w/w) 1-butanol, 6.0% (w/w) sodium lauryl sulphate (SDS), and 0.8% (w/w) n-octane as the separation medium, the fat-soluble vitamins A palmitate, E acetate, and D3 were baseline separated within 11 min. With strongly suppressed EOF, the polarity of the separation voltage was reversed (positive electrode at the outlet); the n-octane micro droplets surrounded by negatively charged SDS molecules migrated towards the detector. The aqueous part of the microemulsion was modified with 20% (w/w) 2-propanol to improve partition between the n-octane phase and the surrounding aqueous medium. The fat-soluble vitamins were separated in order of decreasing hydrophobicity with a high migration time stability (repeatable within 0.1% RSD). Excellent accuracy and precision were obtained when the system was applied for the determination of vitamin E acetate in commercial vitamin tablets; quantitative data corresponded to 97.0% of label claim, intra-day results varied within 1.72% RSD (n=6), and inter-day results varied within 3.22% RSD (n=5). PMID:10823515

  18. A flexible loop-type flow modulator for comprehensive two-dimensional gas chromatography.

    PubMed

    Tranchida, Peter Quinto; Purcaro, Giorgia; Visco, Alessandro; Conte, Lanfranco; Dugo, Paola; Dawes, Peter; Mondello, Luigi

    2011-05-27

    The present investigation is focused on a simple flow modulator (FM), for comprehensive two-dimensional gas chromatography (GCGC). The interface is stable at high temperatures, and consists of a metallic disc (located inside the GC oven) with seven ports, which are connected to an auxiliary pressure source via two branches, to the first and second dimension, to a waste branch (linked to a needle valve) and to an exchangeable modulation loop (2 ports). The ports are connected via micro-channels, etched on one of the inner surfaces of the disc. Modulation is achieved using a two-way electrovalve, connected on one side to the additional pressure source, and to the two metal branches, on the other. An FM enantio-GCpolar-GC method (using a flame ionization detector) was optimized (a 40-?L loop was employed), for the analysis of essential oils. As an example, an application on spearmint oil is shown; the method herein proposed was subjected to validation. Finally, an FM GCGC diesel experiment was carried out, using an apolar-polar column combination, to demonstrate the effectiveness of the modulator in the analysis of a totally different sample-type. PMID:21256493

  19. Method for (236)U Determination in Seawater Using Flow Injection Extraction Chromatography and Accelerator Mass Spectrometry.

    PubMed

    Qiao, Jixin; Hou, Xiaolin; Steier, Peter; Nielsen, Sven; Golser, Robin

    2015-07-21

    An automated analytical method implemented in a flow injection (FI) system was developed for rapid determination of (236)U in 10 L seawater samples. (238)U was used as a chemical yield tracer for the whole procedure, in which extraction chromatography (UTEVA) was exploited to purify uranium, after an effective iron hydroxide coprecipitation. Accelerator mass spectrometry (AMS) was applied for quantifying the (236)U/(238)U ratio, and inductively coupled plasma mass spectrometry (ICPMS) was used to determine the absolute concentration of (238)U; thus, the concentration of (236)U can be calculated. The key experimental parameters affecting the analytical effectiveness were investigated and optimized in order to achieve high chemical yields and simple and rapid analysis as well as low procedure background. Besides, the operational conditions for the target preparation prior to the AMS measurement were optimized, on the basis of studying the coprecipitation behavior of uranium with iron hydroxide. The analytical results indicate that the developed method is simple and robust, providing satisfactory chemical yields (80-100%) and high analysis speed (4 h/sample), which could be an appealing alternative to conventional manual methods for (236)U determination in its tracer application. PMID:26105019

  20. Reducing NO(x) emissions from a nitric acid plant of domestic petrochemical complex: enhanced conversion in conventional radial-flow reactor of selective catalytic reduction process.

    PubMed

    Abbasfard, Hamed; Hashemi, Seyed Hamid; Rahimpour, Mohammad Reza; Jokar, Seyyed Mohammad; Ghader, Sattar

    2013-01-01

    The nitric acid plant of a domestic petrochemical complex is designed to annually produce 56,400 metric tons (based on 100% nitric acid). In the present work, radial-flow spherical bed reactor (RFSBR) for selective catalytic reduction of nitric oxides (NO(x)) from the stack of this plant was modelled and compared with the conventional radial-flow reactor (CRFR). Moreover, the proficiency of a radial-flow (water or nitrogen) membrane reactor was also compared with the CRFR which was found to be inefficient at identical process conditions. In the RFSBR, the space between the two concentric spheres is filled by a catalyst. A mathematical model, including conservation of mass has been developed to investigate the performance of the configurations. The model was checked against the CRFR in a nitric acid plant located at the domestic petrochemical complex. A good agreement was observed between the modelling results and the plant data. The effects of some important parameters such as pressure and temperature on NO(x) conversion were analysed. Results show 14% decrease in NO(x) emission annually in RFSBR compared with the CRFR, which is beneficial for the prevention of NO(x) emission, global warming and acid rain. PMID:24527652

  1. Using active flow technology columns for high through-put and efficient analyses: The drive towards ultra-high through-put high-performance liquid chromatography with mass spectral detection.

    PubMed

    Kocic, Danijela; Shalliker, R Andrew

    2015-11-20

    The performance of active flow technology chromatography columns in parallel segmented flow mode packed with 5 μm Hypersil GOLD particles was compared to conventional UHPLC columns packed with 1.9 μm Hypersil GOLD particles. While the conventional UHPLC columns produced more theoretical plates at the optimum flow rate, when separations were performed at maximum through-put the larger particle size AFT column out-performed the UHPLC column. When both the AFT column and the UHPLC column were operated such that they yielded the same number of theoretical plates per separation, the separation on the AFT column was twice as fast as that on the UHPLC column, with the same level of sensitivity and at just 70% of the back pressure. Furthermore, as the flow velocity further increased the performance gain on the AFT column compared to the UHPLC column improved. An additional advantage of the AFT column was that the flow stream at the exit of the column was split in the radial cross section of the peak profile. This enables the AFT column to be coupled to a flow limiting detector, such as a mass spectrometer. When operated under high through-put conditions separations as fast as six seconds, using mobile phase flow rates in the order of 5-6 mL/min have been recorded. PMID:26363945

  2. Chemical conversion of C2 F6 and uniformity of etching SiO2 in a radial flow plasma reactor

    NASA Astrophysics Data System (ADS)

    Mayer, Thomas M.

    1980-05-01

    Plasma etching of SiO2} with C2}F6} in a radial flow reactor was investigated to determine relationships between chemical aspects of the discharge, operating parameters such as power and flow rates, and uniformity of etching over a large area. The chemical conversion of C2}F6} in the discharge was monitored by infrared spectrometry of the exhaust gases, as a function of discharge power and gas flow rate. The input gas was found to be transformed mainly to CF2} and a polymeric material, and at sufficiently long residence times (1 sec) a "steady state " was achieved. At the steady state condition C2}F6} was found to be 60% converted. The amount of conversion was not influenced by the presence of SiO2} being etched, however, the production of CF4} was reduced by the presence of SiO2}. For a known flow rate and reactor dimensions the concentrations of species as a function of radial position in the reactor were calculated. It was demonstrated that the etch rate of SiO2} was dependent on this radial concentration profile. Uniform etching was obtained if the etching zone lay entirely within the "steady state" region of the discharge. Reduced etch rates or polymerization on the substrates was observed if large concentration gradients (rich in C2}F6}existed in the etching zone. It was concluded that the etch rate of SiO2} is dependent then on the local gas composition in the discharge, and can be manipulated by means of adjusting power and gas flow rates.

  3. Home-made online hyphenation of pressurized liquid extraction, turbulent flow chromatography, and high performance liquid chromatography, Cistanche deserticola as a case study.

    PubMed

    Song, Qingqing; Li, Jun; Liu, Xiao; Zhang, Yuan; Guo, Liping; Jiang, Yong; Song, Yuelin; Tu, Pengfei

    2016-03-18

    Incompatibility between the conventional pressurized liquid extraction (PLE) devices and high performance liquid chromatography (HPLC) extensively hinders direct and green chemical analysis of herbal materials. Herein, a facile PLE module was configured, and then it was online hyphenated with HPLC via a turbulent flow chromatography (TFC) column. Regarding PLE module, a long PEEK tube (0.13×1000mm) was employed to generate desired pressure (approximately 13.0MPa) when warm acidic water (70°C) was delivered as extraction solvent at a high flow rate (2.5mL/min), and a hollow guard column (3.0×4.0mm) was implemented to hold crude materials. Effluent was collected from the outlet of PEEK tube, concentrated, and subjected onto HPLC coupled with hybrid ion trap-time of flight mass spectrometer to assess the extraction efficiency and also to profile the chemical composition of Cistanche deserticola (CD) that is honored as "Ginseng of the desert". Afterwards, a TFC column was introduced to accomplish online transmission of low molecule weight components from PLE module to HPLC coupled with diode array detection, and two electronic 6-port/2-channel valves were in charge of alternating the whole system between extraction (0-3.0min) and elution (3.0-35.0min) phases. Quantitative method was developed and validated for simultaneous determination of eight primary phenylethanoid glycosides in CD using online PLE-TFC-HPLC. All findings demonstrated that the home-made platform is advantageous at direct chemical analysis, as well as time-, solvent-, and material-savings, suggesting a robust tool for chemical fingerprinting of herbs. PMID:26896915

  4. Analysis of endocrine disrupters and related compounds in sediments and sewage sludge using on-line turbulent flow chromatography-liquid chromatography-tandem mass spectrometry.

    PubMed

    Gorga, Marina; Insa, Sara; Petrovic, Mira; Barcel, Dami

    2014-07-25

    A novel fully automated method based on dual column switching using turbulent flow chromatography followed by liquid chromatography coupled to tandem mass spectrometry (TFC-LC-MS/MS) was applied for the determination of endocrine disruptors (EDCs) and related compounds in sediment and sewage sludge samples. This method allows the unequivocal identification and quantification of the most relevant environmental EDCs such as natural and synthetic estrogens and their conjugates, antimicrobials, parabens, bisphenol A (BPA), alkylphenolic compounds, benzotriazoles, and organophosphorus flame retardants, minimizing time of analysis and alleviating matrix effects. Applying this technique, after the extraction of the target compounds by pressurized liquid extraction (PLE), sediment and sewage sludge extracts were directly injected to the chromatographic system and the analytes were concentrated into the clean-up loading column. Using six-port switching system, the analytes were transferred to the analytical column for subsequent detection by MS-MS (QqQ). In order to optimize this multiplexing system, a comparative study employing six types of TurboFlow columns, with different chemical modifications, was performed to achieve the maximum retention of analytes and best elimination of matrix components. Using the optimized protocol low limits of quantification (LOQs) were obtained ranging from 0.0083 to 1.6 ng/g for sediment samples and from 0.10 to 125 ng/g for sewage sludge samples (except for alkylphenol monoethoxylate). The method was used to evaluate the presence and fate of target EDCs in the Ebro River which is the most important river in Spain with intensive agricultural and industrial activities in the basin that contribute to deteriorating soil and water quality. PMID:24909438

  5. Numerical model for the investigation of dual-flow in a spiral counter-current chromatography column.

    PubMed

    Knig, C S; Sutherland, I A

    2007-06-01

    In dual-flow counter-current chromatography (DF-CCC), the two immiscible liquids are flowing in opposite directions in the coil. The method allows for the continuous separation of two solutes. In this study a numerical model was developed to allow for the detailed investigation of flow in such columns. The mesh model of the presented DF spiral column was developed in line with an existing experimental model. The paper presents results during the early filling stages for different rotation directions. These clearly illustrate the performance of the developed model by (1) confirming the importance of flowing the lighter phase from tail to head and the heavier phase from head to tail and (2) by visualising mixing waves and the recognised back and forth "swish-swash" motion as present in CCC in that operating mode. PMID:17353020

  6. Differences in the Properties of the Radial Artery between Cun, Guan, Chi, and Nearby Segments Using Ultrasonographic Imaging: A Pilot Study on Arterial Depth, Diameter, and Blood Flow

    PubMed Central

    Kim, Jaeuk U.; Lee, Yu Jung; Kim, Jong Yeol

    2015-01-01

    Aim of the Study. The three conventional pulse-diagnostic palpation locations (PLs) on both wrists are Cun, Guan, and Chi, and each location reveals different clinical information. To identify anatomical or hemodynamic specificity, we used ultrasonographic imaging to determine the arterial diameter, radial artery depth, and arterial blood flow velocity at the three PLs and at nearby non-PL segments. Methods. We applied an ultrasound scanner to 44 subjects and studied the changes in the arterial diameter and depth as well as in the average/maximum blood flow velocities along the radial artery at three PLs and three non-PLs located more proximally than Chi. Results. All of the measurements at all of the PLs were significantly different (P < 0.01). Artery depth was significantly different among the non-PLs; however, this difference became insignificant after normalization to the arm circumference. Conclusions. Substantial changes in the hemodynamic and anatomical properties of the radial artery around the three PLs were insignificant at the nearby non-PLs segments. This finding may provide a partial explanation for the diagnostic use of Cun, Guan, and Chi. PMID:25763090

  7. MEASUREMENT OF RADIONUCLIDES USING ION CHROMATOGRAPHY AND FLOW-CELL SCINTILLATION COUNTING WITH PULSE SHAPE DISCRIMINATION

    SciTech Connect

    R. A. Fjeld; T.A. DeVol; J.D. Leyba

    2000-03-30

    Radiological characterization and monitoring is an important component of environmental management activities throughout the Department of Energy complex. Gamma-ray spectroscopy is the technology most often used for the detection of radionuclides. However, radionuclides which cannot easily be detected by gamma-ray spectroscopy, such as pure beta emitters and transuranics, pose special problems because their quantification generally requires labor intensive radiochemical separations procedures that are time consuming and impractical for field applications. This project focused on a technology for measuring transuranics and pure beta emitters relatively quickly and has the potential of being field deployable. The technology combines ion exchange liquid chromatography and on-line alpha/beta pulse shape discriminating scintillation counting to produce simultaneous alpha and beta chromatograms. The basic instrumentation upon which the project was based was purchased in the early 1990's. In its original commercial form, the instrumentation was capable of separating select activation/fission products in ionic forms from relatively pure aqueous samples. We subsequently developed the capability of separating and detecting actinides (thorium, uranium, neptunium, plutonium, americium, and curium) in less than 30 minutes (Reboul, 1993) and realized that the potential time savings over traditional radiochemical methods for isolating some of these radionuclides was significant. However, at that time, the technique had only been used for radionuclide concentrations that were considerably above environmental levels and for aqueous samples of relatively high chemical purity. For the technique to be useful in environmental applications, development work was needed in lowering detection limits; to be useful in applications involving non-aqueous matrices such as soils and sludges or complex aqueous matrices such as those encountered in waste samples, development work was needed in sample preparation and processing. The general goal of this project was to address the issues mentioned above, and in so doing transform an interesting laboratory technique of limited applicability into a robust field instrument suitable for environmental restoration and waste management applications. The project consisted of the following tasks: (1) development of a low background, flow-cell detector, (2) identification of sample chemical and radiological interferences, (3) development of protocols for processing waste and/or environmental samples, and (4) integration and testing of the prototype system. The scope of work associated with these tasks has been completed and the report for Tasks 1-3 was submitted previously. Presented here are the results for Task 4.

  8. An overview of gallium nitride growth chemistry and its effect on reactor design: Application to a planetary radial-flow CVD system

    NASA Astrophysics Data System (ADS)

    Parikh, Rinku P.; Adomaitis, Raymond A.

    2006-01-01

    In this paper, gallium nitride (GaN) growth chemistry is characterized by two competing reaction pathways. An overview of GaN gas-phase and surface-phase chemistry is used to generate a comprehensive model for epitaxial GaN growth from the commonly used precursors, trimethylgallium ((CH 3) 3Ga) and ammonia (NH 3). The role of reactor geometry in controlling the selectivity among the competing reaction pathways is explored in the context of a planetary radial-flow CVD system. Finally, application of a geometrically based uniformity criterion is presented for film uniformity optimization.

  9. Simultaneous revascularization and coverage of a complex volar hand blast injury: case report using a contralateral radial forearm flow-through flap.

    PubMed

    Grewal, Navanjun S; Kumar, Anand R; Onsgard, Christina K; Taylor, Bruce J

    2008-08-01

    War wounds have created a unique reconstructive challenge for successful functional limb salvage. Various injury patterns related to improvised explosive devices (IEDs) occur and proper reconstruction goes a long way in reducing subsequent disfigurement and morbidity. One case in which a contralateral radial forearm flow-through flap is used for simultaneous revascularization and coverage of an IED hand blast injury is described. The advantages of this flap was its consistent arterial anatomy and long vascular pedicle. The thin skin paddle was used for soft tissue coverage of flexor tendon repair, median and ulnar nerve reconstruction, and metacarpal bone open reduction and internal fixation (ORIF). Recovery of motor function was satisfactory. PMID:18751601

  10. Oxidation of element 102, nobelium, with flow electrolytic column chromatography on an atom-at-a-time scale.

    PubMed

    Toyoshima, Atsushi; Kasamatsu, Yoshitaka; Tsukada, Kazuaki; Asai, Masato; Kitatsuji, Yoshihiro; Ishii, Yasuo; Toume, Hayato; Nishinaka, Ichiro; Haba, Hiromitsu; Ooe, Kazuhiro; Sato, Wataru; Shinohara, Atsushi; Akiyama, Kazuhiko; Nagame, Yuichiro

    2009-07-01

    We report here on the successful oxidation of element 102, nobelium (No), on an atom-at-a-time scale in 0.1 M alpha-hydroxyisobutyric acid (alpha-HIB) solution using a newly developed technique, flow electrolytic column chromatography. It is found that the most stable ion, No(2+), is oxidized to No(3+) within 3 min and that the oxidized No complex with alpha-HIB holds the trivalent state in the column above an applied potential of 1.0 V. PMID:19514720

  11. Packing of large-scale chromatography columns with irregularly shaped glass based resins using a stop-flow method.

    PubMed

    Siu, Sun Chau; Chia, Celeste; Mok, Yanglin; Pattnaik, Priyabrata

    2014-01-01

    Rigid chromatography resins, such as controlled pore glass based adsorbents, offer the advantage of high permeability and a linear pressure-flow relationship irrespective of column diameter which improves process time and maximizes productivity. However, the rigidity and irregularly shaped nature of these resins often present challenges in achieving consistent and uniform packed beds as formation of bridges between resin particles can hinder bed consolidation. The standard flow-pack method when applied to irregularly shaped particles does not yield well-consolidated packed beds, resulting in formation of a head space and increased band broadening during operation. Vibration packing methods requiring the use of pneumatically driven vibrators are recommended to achieve full packed bed consolidation but limitations in manufacturing facilities and equipment may prevent the implementation of such devices. The stop-flow packing method was developed as an improvement over the flow-pack method to overcome these limitations and to improve bed consolidation without the use of vibrating devices. Transition analysis of large-scale columns packed using the stop-flow method over multiple cycles has shown a two- to three-fold reduction of change in bed integrity values as compared to a flow-packed bed demonstrating an improvement in packed bed stability in terms of the height equivalent to a theoretical plate (HETP) and peak asymmetry (As ). PMID:25080096

  12. Minimizing ultraviolet noise due to mis-matches between detector flow cell and post column mobile phase temperatures in supercritical fluid chromatography: effect of flow cell design.

    PubMed

    Berger, Terry A

    2014-10-17

    A mis-match between the post-column mobile phase temperature and the UV detector flow cell temperature can cause significant UV noise in supercritical fluid chromatography (SFC). Deviations as little as 5 C can increase noise as much as 5 times, making the detector unsuited for trace analysis. Two approaches were used to minimize this noise. When a flow cell was in direct thermal contact (metal on metal) with the detector optical bench, the mobile phase temperature was actively controlled to the measured flow cell temperature, by using one of the heat exchangers (HX) in the column compartment. However, with some older, but still widely used flow cell designs, this required repeated, hourly monitoring of the flow cell temperature and repeated manual adjustment of the heat exchanger temperature, due to thermal drift. Flow cell design had a strong influence on susceptibility to this thermally induced noise. Thermally insulating the flow cell from the optical bench made some cells much less susceptible to such thermally induced noise. Five different flow cells, some insulated, some un-insulated, were evaluated. Most had a truncated conical flow path, but one had a cylindrical flow path. Using either approach, the ASTM noise, with a 10mm, 13 ?L conical flow cell, could be optimized to ?0.007 mAU at 2.5 Hz, in SFC, which is very near the 0.006 mAU manufacturer's specification for HPLC. The insulated version of this flow cell required far less optimization, compared to the un-insulated version. At 150 bar, an experimental 3mm, 2 ?L flow cell, with only one side insulated, yielded noise slightly too high (?0.16-0.18 mAU) for trace analysis, at 80 Hz. However, at 200 bar, noise at 80 Hz was <0.06 mAU, which should allow quantification of a 1 mAU tall trace component with a signal to noise ratio (S/N) >10. Even partially un-insulated, this flow cell design was much less susceptible to thermally induced noise. Further insulating this flow cell design failed to improve performance. PMID:25189330

  13. Effects of Flow Rate and Alkali-to-Acid Ratio on the Displacement of Acidic Oil by Alkaline Solutions in Radial Porous Media.

    PubMed

    Hornof; Neale; Gholam-Hosseini

    2000-11-01

    Alkaline flooding is a method of enhanced oil recovery that relies on the formation of surface-active substances in situ by a chemical reaction between acidic components in the oil and an alkaline reagent. As the injected alkali advances through the porous medium, it keeps contacting fresh oil. At some moment dependent on the alkali/acid concentrations and the velocity, the alkali at the advancing front may become depleted and the flood becomes interfacially nonreactive. The present study is aimed at investigating the above-mentioned phenomena. Displacement studies were conducted in radial cells containing sintered glass beads as a porous medium. Light paraffin oil acidified with 10 mmol/L of linoleic acid served as the displaced (oil) phase while the displacing aqueous solution contained 0-25 mmol/L of sodium hydroxide. The highest oil recovery was obtained under the conditions of low flow rate and high alkali concentration. Increasing the flow rate at high NaOH concentration resulted in decreasing oil recovery up to a certain threshold flow rate. Conversely, the amount of oil recovered by waterflooding only (no alkali) initially increased with increasing flow rate up to the same threshold flow rate beyond which there was no difference between the alkaline flood and a waterflood. Copyright 2000 Academic Press. PMID:11082266

  14. Determination of irinotecan and SN38 in human plasma by TurboFlow liquid chromatography-tandem mass spectrometry.

    PubMed

    Herviou, P; Richard, D; Roche, L; Pinguet, J; Libert, F; Eschalier, A; Durando, X; Authier, N

    2016-01-25

    Irinotecan is a cytotoxic agent used in the treatment of metastatic colorectal cancer. Irinotecan is a prodrug when is converted in vivo to an active metabolite SN38, which has potent pharmacological activity. SN38 is then inactivated and excreted as SN38-glucuronide. High-performance liquid chromatography-mass spectrometry is a widely used bioanalysis technique that can be coupled to the turbulent-flow extraction line to shorten preparation time. A technique was developed to quantify irinotecan and its metabolite by liquid chromatography-tandem mass spectrometry coupled with a turbulent-flow online extraction method. Assays were performed on 100?L of plasma after protein precipitation. The supernatant is injected directly into the extraction column, transferred to the chromatographic column, and analyzed by tandem mass spectrometry. Linearity, reproducibility and repeatability of the method were validated on a concentration range of 25-2500ng/mL for irinotecan and 5-500ng/mL for SN38. For the low limit of quantification of irinotecan and SN38, precision is 6.31% and 8.73%, and accuracy is 84.0% and 91.8%, respectively. The SN38-glucuronide determination protocol included a hydrolyzation step. This method was successfully used to quantify irinotecan, SN38 and SN38-G in human plasma in a clinical trial. PMID:26580826

  15. Design of radial turbomachines

    SciTech Connect

    Whitfield, A.; Baines, N.C.

    1990-01-01

    This book describes the current technology and design methods for centrifugal compressors and radial turbines working in compressible flow. A recognition of current computer-aid design methods is included as well as computer program listings for preliminary design. The problems posed by specific applications are dealt with. Surveys of such areas as: techniques for the suppression of surge in centrifugal compressors and consequent widening of the operating range, and the problems of pulse operation of radial turbines as encountered in turbocharger applications are presented.

  16. Peristaltic flow of a Jeffrey fluid under the effect of radially varying magnetic field in a tube with an endoscope

    NASA Astrophysics Data System (ADS)

    Abd-Alla, A. M.; Abo-Dahab, S. M.; Kilicman, A.

    2015-06-01

    The influence of an endoscope on peristaltic flow of a Jeffrey fluid through the cylindrical cavity between concentric tubes with variable magnetic field has been investigated. The governing equations of two dimensional fluid have been simplified under the consideration of long wavelength and low Reynolds number approximation. Exact analytical calculations are carried out for the pressure gradient, velocity, pressure rise, friction force on the inner and outer tubes and shear stress. The effect of the non-dimensional wave amplitude, the variable magnetic field, the ratio of relaxation of retardation time, the radius ratio and the non-dimensional volume flow are analyzed theoretically and computed numerically. Comparison was made with the results obtained in the presence and absence of variable magnetic field and an endoscope. The results indicate that the effect of the non-dimensional wave amplitude, variable magnetic field, ratio of relaxation to retardation time, radius ratio and non-dimensional volume flow on peristaltic flow are very pronounced.

  17. Removal of nitrogen and organic matter in a radial-flow aerobic-anoxic immobilized biomass reactor used in the posttreatment of anaerobically treated effluent.

    PubMed

    Fazolo, Ajadir; Foresti, Eugenio; Zaiat, Marcelo

    2007-07-01

    This work reports on the removal of organic matter and nitrogen in a radial-flow aerobic-anoxic immobilized biomass (RAIB) reactor fed with domestic sewage pretreated in a horizontal-flow anaerobic immobilized biomass (HAIB) reactor. Polyurethane foam was used as support material for biomass attachment in both reactors. In batch experiments, a first-order kinetic model with residual concentration represented the organic matter removal rate, whereas nitrogen conversion followed a pseudo-first-order reaction in series model, with kinetic constants k1 (ammonium to nitrite) and k2 (nitrite to nitrate) of 0.25 and 6.62 h(-1), respectively. The RAIB reactor was operated in continuous-flow mode and changes in the airflow rate and hydraulic retention time were found to interfere in the apparent kinetic constants to the nitritation (k1) and nitratation (k2). Nitrification and denitrification were achieved in the partially aerated RAIB reactor operating with hydraulic retention times of 3.3 h and 2.7 h in the aerobic and anoxic zones, respectively. Ethanol was added in the anoxic zone of the reactor to promote denitrification. The effluent flow of the RAIB reactor presented a COD of 52 mg l(-1), and concentrations of 2 mg N - NH4(+)1(-1), 1.24 mg N - N02(-)1(-1) and 3.46 mg N - N03(-)1(-1). PMID:18025567

  18. Transient radial flow to a well in an unconfined aquifer. Part 1, An evaluation of some conceptual methods

    SciTech Connect

    Narasimhan, T.N.; Zhu, Ming

    1991-08-01

    The analytic solutions of Boulton (1954) and Neuman (1972) for transient flow to a well in an unconfined aquifer are based on the assumption that the role of the unsaturated zone can be adequately accounted for by restricting attention to the release of water from the zone through which the water table moves. Both researchers mathematically treat this released water as a time-dependent source term. The differences between the models of Boulton and Neuman are that the former neglects vertical components of flow in the aquifer, but allows for an exponential process for the release of water as a function of time, whereas the latter assumes instantaneous release from storage, but accounts for vertical components of flow. Given this set of assumptions, we examine the applicability of these two methods using a general purpose numerical model through a process of verification extension and comparison. The issues addressed include: the role of well-bore storage in masking intermediate-time behavior, combined effects of exponential release as well as vertical flow, logic for vertical averaging of drawdowns, and the sensitivity of system response to the magnitude of specific yield. The issue of how good the assumptions of Boulton and Neuman are in the context of the general theory of unsaturated flow is addressed in part 2 of this two-part series of reports.

  19. MHD flow and heat transfer of a viscous fluid over a radially stretching power-law sheet with suction/injection in a porous medium

    NASA Astrophysics Data System (ADS)

    Khan, M.; Munir, A.; Shahzad, A.; Shah, A.

    2015-03-01

    A steady boundary layer flow and heat transfer over a radially stretching isothermal porous sheet is analyzed. Stretching is assumed to follow a radial power law, and the fluid is electrically conducting in the presence of a transverse magnetic field with a very small magnetic Reynolds number. The governing nonlinear partial differential equations are reduced to a system of nonlinear ordinary differential equations by using appropriate similarity transformations, which are solved analytically by the homotopy analysis method (HAM) and numerically by employing the shooting method with the adaptive Runge-Kutta method and Broyden's method in the domain [0,?). Analytical expressions for the velocity and temperature fields are derived. The influence of pertinent parameters on the velocity and temperature profiles is discussed in detail. The skin friction coefficient and the local Nusselt number are calculated as functions of several influential parameters. The results predicted by both methods are demonstrated to be in excellent agreement. Moreover, HAM results for a particular problem are also compared with exact solutions.

  20. Lateral flow microarrays: a novel platform for rapid nucleic acid detection based on miniaturized lateral flow chromatography

    PubMed Central

    Carter, Darren J.; Cary, R. Bruce

    2007-01-01

    Widely used nucleic acid assays are poorly suited for field deployment where access to laboratory instrumentation is limited or unavailable. The need for field deployable nucleic acid detection demands inexpensive, facile systems without sacrificing information capacity or sensitivity. Here we describe a novel microarray platform capable of rapid, sensitive nucleic acid detection without specialized instrumentation. The approach is based on a miniaturized lateral flow device that makes use of hybridization-mediated target capture. The miniaturization of lateral flow nucleic acid detection provides multiple advantages over traditional lateral flow devices. Ten-microliter sample volumes reduce reagent consumption and yield analyte detection times, excluding sample preparation and amplification, of <120?s while providing sub-femtomole sensitivity. Moreover, the use of microarray technology increases the potential information capacity of lateral flow. Coupled with a hybridization-based detection scheme, the lateral flow microarray (LFM) enables sequence-specific detection, opening the door to highly multiplexed implementations for broad-range assays well suited for point-of-care and other field applications. The LFM system is demonstrated using an isothermal amplification strategy for detection of Bacillus anthracis, the etiologic agent of anthrax. RNA from as few as two B. anthracis cells was detected without thermocycling hardware or fluorescence detection systems. PMID:17478499

  1. ANALYTICAL APPROXIMATION OF THE BIODEGRADATION RATE FOR IN SITU BIOREMEDIATION OF GROUNDWATER UNDER IDEAL RADIAL FLOW CONDITIONS. (R824785)

    EPA Science Inventory

    We derive the long-term biodegradation rate of an organic contaminant (substrate) for an in situ bioremediation model with axisymmetric flow conditions. The model presumes that a nonsorbing electron acceptor is injected into a saturated homogeneous porous medium which initially c...

  2. Online spectrophotometric determination of Fe(II) and Fe(III) by flow injection combined with low pressure ion chromatography.

    PubMed

    Chen, Shujuan; Li, Nan; Zhang, Xinshen; Yang, Dongjing; Jiang, Heimei

    2015-03-01

    A simple and new low pressure ion chromatography combined with flow injection spectrophotometric procedure for determining Fe(II) and Fe(III) was established. It is based on the selective adsorption of low pressure ion chromatography column to Fe(II) and Fe(III), the online reduction reaction of Fe(III) and the reaction of Fe(II) in sodium acetate with phenanthroline, resulting in an intense orange complex with a suitable absorption at 515nm. Various chemical (such as the concentration of colour reagent, eluant and reductive agent) and instrumental parameters (reaction coil length, reductive coil length and wavelength) were studied and were optimized. Under the optimum conditions calibration graph of Fe(II)/Fe(III) was linear in the Fe(II)/Fe(III) range of 0.040-1.0mg/L. The detection limit of Fe(III) and Fe(II) was respectively 3.09 and 1.55μg/L, the relative standard deviation (n=10) of Fe(II) and Fe(III) 1.89% and 1.90% for 0.5mg/L of Fe(II) and Fe(III) respectively. About 2.5 samples in 1h can be analyzed. The interfering effects of various chemical species were studied. The method was successfully applied in the determination of water samples. PMID:25523043

  3. Online spectrophotometric determination of Fe(II) and Fe(III) by flow injection combined with low pressure ion chromatography

    NASA Astrophysics Data System (ADS)

    Chen, Shujuan; Li, Nan; Zhang, Xinshen; Yang, Dongjing; Jiang, Heimei

    2015-03-01

    A simple and new low pressure ion chromatography combined with flow injection spectrophotometric procedure for determining Fe(II) and Fe(III) was established. It is based on the selective adsorption of low pressure ion chromatography column to Fe(II) and Fe(III), the online reduction reaction of Fe(III) and the reaction of Fe(II) in sodium acetate with phenanthroline, resulting in an intense orange complex with a suitable absorption at 515 nm. Various chemical (such as the concentration of colour reagent, eluant and reductive agent) and instrumental parameters (reaction coil length, reductive coil length and wavelength) were studied and were optimized. Under the optimum conditions calibration graph of Fe(II)/Fe(III) was linear in the Fe(II)/Fe(III) range of 0.040-1.0 mg/L. The detection limit of Fe(III) and Fe(II) was respectively 3.09 and 1.55 μg/L, the relative standard deviation (n = 10) of Fe(II) and Fe(III) 1.89% and 1.90% for 0.5 mg/L of Fe(II) and Fe(III) respectively. About 2.5 samples in 1 h can be analyzed. The interfering effects of various chemical species were studied. The method was successfully applied in the determination of water samples.

  4. Determination of thermal conductivities of Sn-Zn lead-free solder alloys with radial heat flow and Bridgman-type apparatus

    NASA Astrophysics Data System (ADS)

    Meydaneri, Fatma; Saati, Buket; Gndz, Mehmet; zdemir, Mehmet

    2013-11-01

    The variations of thermal conductivities of solid phases versus temperature for pure Sn, pure Zn and Sn-9 wt.% Zn, Sn-14 wt.% Zn, Sn-50 wt.% Zn, Sn-80 wt.% Zn binary alloys were measured with a radial heat flow apparatus. The thermal conductivity ratios of liquid phase to solid phase for the pure Sn, pure Zn and eutectic Sn-9 wt.% Zn alloy at their melting temperature are found with a Bridgman-type directional solidification apparatus. Thus, the thermal conductivities of liquid phases for pure Sn, pure Zn and eutectic Sn-9 wt.% Zn binary alloy at their melting temperature were evaluated by using the values of solid phase thermal conductivities and the thermal conductivity ratios of liquid phase to solid phase.

  5. The effects of the secondary fluid temperature on the energy transfer in an unsteady ejector with a radial-flow diffuser

    NASA Astrophysics Data System (ADS)

    Ababneh, Amer Khalil; Jawarneh, Ali M.; Tlilan, Hitham M.; Ababneh, Mohammad K.

    2009-11-01

    Unsteady ejectors are devices whereby energy is exchanged between directly interacting fluids. Unlike steady ejectors, the mechanism responsible for the energy transfer is reversible in nature and thus higher efficiencies are perceivable. A potential application for PEE is for enhancement in output power per weight as in turbochargers. The unsteady ejector when used as a turbocharger the device is expected to perform under wide range of ambient temperatures. Therefore, it is important to investigate the effects of the temperature of the induced ambient air on the energy transfer. The radial-flow ejector, which usually leads to higher-pressure ratios with fewer stages, was selected for the investigation. The flow field is investigated at two Mach numbers 2.5 and 3.0 utilizing rectangular short-length supersonic nozzles for accelerating the primary fluid. Fundamental to the enhancement of these devices performance relies on the management of the flow field in such a way to minimize entropy production. The numerical analyses were conducted utilizing a package of computational fluid dynamics.

  6. Rapid identification of airborne biological particles by flow cytometry, gas chromatography, and genetic probes. Final report, January 1995-January 1997

    SciTech Connect

    Wick, C.H.; Carlon, H.R.; Edmonds, R.L.; Robert, L.; Blew, J.

    1997-09-01

    Detection of airborne biological particulates is a primary mission of the U.S. Army Edgewood Research, Development and Engineering Center biological defense program. If biological particles could be characterized according to their unique physical and biochemical profiles, detection and perhaps even identification of the particles might be possible. This study focused upon microbial particles, more specifically upon fungal spores, yeast cells, and bacterial cells. Physical characteristics of the particles, it was proposed, could be detected by flow cytometry, while their biochemical profiles could be determined by gas chromatography, and their genetic identity could be obtained by either a suitable genetic probe or by matching its genetic fingerprint. Genetic techniques were not attempted in the work reported here, but the approach was investigated further. Trial results were encouraging.

  7. Preparation of pure, high titer, pseudoinfectious Flavivirus particles by hollow fiber tangential flow filtration and anion exchange chromatography.

    PubMed

    Mundle, Sophia T; Giel-Moloney, Maryann; Kleanthous, Harry; Pugachev, Konstantin V; Anderson, Stephen F

    2015-08-20

    Purification of enveloped viruses such as live flavivirus vaccine candidates poses a challenge as one must retain viral infectivity to preserve immunogenicity. Here we describe a laboratory-scale purification procedure for two replication defective (single-cycle) flavivirus variants for use in a pre-clinical setting. The two step purification scheme based on hollow fiber tangential flow filtration (TFF) followed by anion exchange chromatography using convective interaction media (CIM(®)) monoliths results in a ∼60% recovery of infectious virus titer and can be used to prepare nearly homogenous, highly purified vaccine viruses with titers as high as 1×10(9) focus forming units per mL. Flavivirus virions prepared by this method are 2 and 3 orders of magnitude more pure with respect to dsDNA and BHK host cell proteins, respectively, as compared to the raw feed stream. PMID:25498209

  8. Fraction Collection from Capillary Liquid Chromatography and Off-line Electrospray Ionization Mass Spectrometry using Oil Segmented Flow

    PubMed Central

    Li, Qiang; Pei, Jian; Song, Peng; Kennedy, Robert T.

    2010-01-01

    Off-line analysis and characterization of samples separated by capillary liquid chromatography (LC) has been problematic using conventional approaches to fraction collection. We demonstrate collection of nanoliter fractions by forming plugs of effluent from a 75 ?m inner diameter LC column segmented by an immiscible oil such as perfluorodecalin. The plugs are stored in tubing that can then be used to manipulate the samples. Off-line electrospray ionization mass spectrometry (ESI-MS) was used to characterize the samples. ESI-MS was performed by directly pumping the segmented plugs into a nanospray emitter tip. Critical parameters including the choice of oils, ESI voltage, and flow rates that allows successful direct infusion analysis were investigated. Best signals were obtained under conditions in which the oil did not form an electrospray but was siphoned away from the tip. Off-line analysis showed preservation of the chromatogram with no loss of resolution. The method was demonstrated to allow changes in flow rate during the analysis. Specifically, decreases in flow rate were used to allow extended MS analysis time on selected fractions, similar to peak parking. PMID:20491430

  9. Radial lean direct injection burner

    DOEpatents

    Khan, Abdul Rafey; Kraemer, Gilbert Otto; Stevenson, Christian Xavier

    2012-09-04

    A burner for use in a gas turbine engine includes a burner tube having an inlet end and an outlet end; a plurality of air passages extending axially in the burner tube configured to convey air flows from the inlet end to the outlet end; a plurality of fuel passages extending axially along the burner tube and spaced around the plurality of air passage configured to convey fuel from the inlet end to the outlet end; and a radial air swirler provided at the outlet end configured to direct the air flows radially toward the outlet end and impart swirl to the air flows. The radial air swirler includes a plurality of vanes to direct and swirl the air flows and an end plate. The end plate includes a plurality of fuel injection holes to inject the fuel radially into the swirling air flows. A method of mixing air and fuel in a burner of a gas turbine is also provided. The burner includes a burner tube including an inlet end, an outlet end, a plurality of axial air passages, and a plurality of axial fuel passages. The method includes introducing an air flow into the air passages at the inlet end; introducing a fuel into fuel passages; swirling the air flow at the outlet end; and radially injecting the fuel into the swirling air flow.

  10. Numerical investigation of a coupled moving boundary model of radial flow in low-permeable stress-sensitive reservoir with threshold pressure gradient

    NASA Astrophysics Data System (ADS)

    Wen-Chao, Liu; Yue-Wu, Liu; Cong-Cong, Niu; Guo-Feng, Han; Yi-Zhao, Wan

    2016-02-01

    The threshold pressure gradient and formation stress-sensitive effect as the two prominent physical phenomena in the development of a low-permeable reservoir are both considered here for building a new coupled moving boundary model of radial flow in porous medium. Moreover, the wellbore storage and skin effect are both incorporated into the inner boundary conditions in the model. It is known that the new coupled moving boundary model has strong nonlinearity. A coordinate transformation based fully implicit finite difference method is adopted to obtain its numerical solutions. The involved coordinate transformation can equivalently transform the dynamic flow region for the moving boundary model into a fixed region as a unit circle, which is very convenient for the model computation by the finite difference method on fixed spatial grids. By comparing the numerical solution obtained from other different numerical method in the existing literature, its validity can be verified. Eventually, the effects of permeability modulus, threshold pressure gradient, wellbore storage coefficient, and skin factor on the transient wellbore pressure, the derivative, and the formation pressure distribution are analyzed respectively. Project supported by the National Natural Science Foundation of China (Grant No. 51404232), the China Postdoctoral Science Foundation (Grant No. 2014M561074), and the National Science and Technology Major Project, China (Grant No. 2011ZX05038003).

  11. The membrane dialysis bioreactor with integrated radial-flow fixed bed--a new approach for continuous cultivation of animal cells.

    PubMed

    Bohmann, A; Prtner, R; Schmieding, J; Kasche, V; Mrkl, H

    1992-01-01

    A hybridoma cell was cultivated continuously in a membrane dialysis bioreactor with an integrated radial-flow fixed bed consisting of porous Siran carriers over a period of 6 weeks. Antibodies accumulated to an average of 100 mg l-1, approx. 10 times more than in fixed bed cultures without dialysis membrane. Serum costs could be reduced about 85% due to an appropriate feeding strategy. Siran carriers with 3-5 mm diameter showed an advantage compared to those with 1-2 mm diameter. For the 3-5 mm carrier the specific glucose uptake rate and the MAb production rate were constant, if the velocity was between 0.09 mm s-1 and 0.75 mm s-1. At higher velocities cells are washed out of the bed. Furthermore antibody consistency and cell stability were verified in long-term cultivations over a period of 96 days. From an estimation of the antibody concentration reachable with the reactor concept under optimal conditions a concentration 45 times higher compared to axial-flow fixed bed reactors and 11 times higher compared to stirred tank reactors can be expected. PMID:1369181

  12. Radiolabeling and Quantification of Cellular Levels of Phosphoinositides by High Performance Liquid Chromatography-coupled Flow Scintillation.

    PubMed

    Ho, Cheuk Y; Choy, Christopher H; Botelho, Roberto J

    2016-01-01

    Phosphoinositides (PtdInsPs) are essential signaling lipids responsible for recruiting specific effectors and conferring organelles with molecular identity and function. Each of the seven PtdInsPs varies in their distribution and abundance, which are tightly regulated by specific kinases and phosphatases. The abundance of PtdInsPs can change abruptly in response to various signaling events or disturbance of the regulatory machinery. To understand how these events lead to changes in the amount of PtdInsPs and their resulting impact, it is important to quantify PtdInsP levels before and after a signaling event or between control and abnormal conditions. However, due to their low abundance and similarity, quantifying the relative amounts of each PtdInsP can be challenging. This article describes a method for quantifying PtdInsP levels by metabolically labeling cells with (3)H-myo-inositol, which is incorporated into PtdInsPs. Phospholipids are then precipitated and deacylated. The resulting soluble (3)H-glycero-inositides are further extracted, separated by high-performance liquid chromatography (HPLC), and detected by flow scintillation. The labeling and processing of yeast samples is described in detail, as well as the instrumental setup for the HPLC and flow scintillator. Despite losing structural information regarding acyl chain content, this method is sensitive and can be optimized to concurrently quantify all seven PtdInsPs in cells. PMID:26780479

  13. MERIDL- VELOCITIES AND STREAMLINES ON THE HUB-SHROUD MIDCHANNEL STREAM SURFACE OF AN AXIAL, RADIAL, OR MIXED FLOW TURBOMACHINE OR ANNULAR DUCT

    NASA Technical Reports Server (NTRS)

    Katsanis, T.

    1994-01-01

    This computer program was developed for calculating the subsonic or transonic flow on the hub-shroud mid-channel stream surface of a single blade row of a turbomachine. The design and analysis of blades for compressors and turbines ideally requires methods for analyzing unsteady, three-dimensional, turbulent viscous flow through a turbomachine. Since an exact solution is impossible at present, solutions on two-dimensional surfaces are calculated to obtain a quasi-three dimensional solution. When three-dimensional effects are important, significant information can be obtained from a solution on a cross-sectional surface of the passage normal to the flow. With this program, a solution to the equations of flow on the meridional surface can be carried out. This solution is chosen when the turbomachine under consideration has significant variation in flow properties in the hubshroud direction, especially when input is needed for use in blade-to-blade calculations. The program can also perform flow calculations for annular ducts without blades. This program should prove very useful in the design and analysis of any turbomachine. This program calculates a solution for two-dimensional, adiabatic shockfree flow. The flow must be essentially subsonic, but there may be local areas of supersonic flow. To obtain the solution, this program uses both the finite difference and the quasi-orthogonal (velocity gradient) methods combined in a way that takes maximum advantage of both. The finite-difference method solves a finite-difference equation along the meridional stream surface in a very efficient manner but is limited to subsonic velocities. This approach must be used in cases where the blade aspect ratios are above one, cases where the passage is curved, and cases with low hub-tip-ratio blades. The quasi-orthogonal method solves the velocity gradient equation on the meridional surface and is used if it is necessary to extend the range of solutions into the transonic regime. In general the blade row may be fixed or rotating and the blades may be twisted and leaned. The flow may be axial, radial, or mixed. The upstream and downstream flow conditions can vary from hub to shroud with provisions made for an approximate correction for loss of stagnation pressure. Also, viscous forces are neglected along solution mesh lines running from hub to tip. The capabilities of this program include handling of nonaxial flows without restriction, annular ducts without blades, and specified streamwise loss distributions. This program is written in FORTRAN IV for batch execution and has been implemented on an IBM 360 computer with a central memory requirement of approximately 700K of 8 bit bytes. This core requirement can be reduced depending on the size of the problem and the desired solution accuracy. This program was developed in 1977.

  14. Multidimensional gas chromatography with capillary flow technology and LTM-GC.

    PubMed

    Luong, Jim; Gras, Ronda; Yang, Grace; Cortes, Hernan; Mustacich, Robert

    2008-10-01

    2-D GC is a logical and cost effective extension to 1-D GC for improving the separation resolution, selectivity, and peak capacity of an analytical system. The advent of electronic pressure control systems that are accurate to the third decimal place, combined with recently innovated chromatographic devices such as capillary flow technology, has eliminated many deficiencies encountered in current conventional 2-D GC by making the technique reliable and simple to implement in both production and research analytical facilities. Low thermal mass GC (LTM-GC) was successfully integrated with capillary flow technology to further enhance overall 2-D GC chromatographic system performance by providing not only faster throughput via rapid heating and cooling, but independent temperature control for each dimension to maximize separation power. As an example, despite the enhanced peak capacity obtained from conventional 2-D GC, alkyl naphthalene isomers such as 2,3-dimethyl and 1,4-dimethyl naphthalene coeluted. These two critical compounds were well resolved (R = 5.2) using 2-D GC with LTM-GC with a similar analytical time. This paper demonstrates the benefits of combining capillary flow technology with LTM-GC to provide major enhancements to conventional 2-D GC. The synergy of these techniques is highlighted with practical industrial applications. PMID:18792007

  15. Radial Erosion

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    The ejecta surrounding the crater (off image to the left) in this image has undergone significant erosion by the wind. The wind has stripped the surface features from the ejecta and has started to winnow away the ejecta blanket. Near the margin of the ejecta the wind is eroding along a radial pattern -- taking advantage of radial emplacement. Note the steep margin of the ejecta blanket. Most, if not all, of the fine ejecta material has been removed and the wind in now working on the more massive continuous ejecta blanket.

    Image information: VIS instrument. Latitude 12.5, Longitude 197.4 East (162.6 West). 37 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  16. Top-down and bottom-up lipidomic analysis of rabbit lipoproteins under different metabolic conditions using flow field-flow fractionation, nanoflow liquid chromatography and mass spectrometry.

    PubMed

    Byeon, Seul Kee; Kim, Jin Yong; Lee, Ju Yong; Chung, Bong Chul; Seo, Hong Seog; Moon, Myeong Hee

    2015-07-31

    This study demonstrated the performances of top-down and bottom-up approaches in lipidomic analysis of lipoproteins from rabbits raised under different metabolic conditions: healthy controls, carrageenan-induced inflammation, dehydration, high cholesterol (HC) diet, and highest cholesterol diet with inflammation (HCI). In the bottom-up approach, the high density lipoproteins (HDL) and the low density lipoproteins (LDL) were size-sorted and collected on a semi-preparative scale using a multiplexed hollow fiber flow field-flow fractionation (MxHF5), followed by nanoflow liquid chromatography-ESI-MS/MS (nLC-ESI-MS/MS) analysis of the lipids extracted from each lipoprotein fraction. In the top-down method, size-fractionated lipoproteins were directly infused to MS for quantitative analysis of targeted lipids using chip-type asymmetrical flow field-flow fractionation-electrospray ionization-tandem mass spectrometry (cAF4-ESI-MS/MS) in selected reaction monitoring (SRM) mode. The comprehensive bottom-up analysis yielded 122 and 104 lipids from HDL and LDL, respectively. Rabbits within the HC and HCI groups had lipid patterns that contrasted most substantially from those of controls, suggesting that HC diet significantly alters the lipid composition of lipoproteins. Among the identified lipids, 20 lipid species that exhibited large differences (>10-fold) were selected as targets for the top-down quantitative analysis in order to compare the results with those from the bottom-up method. Statistical comparison of the results from the two methods revealed that the results were not significantly different for most of the selected species, except for those species with only small differences in concentration between groups. The current study demonstrated that top-down lipid analysis using cAF4-ESI-MS/MS is a powerful high-speed analytical platform for targeted lipidomic analysis that does not require the extraction of lipids from blood samples. PMID:26087967

  17. Development and validation of a radial inflow turbine model for simulation of the SNL S-CO2 split-flow loop.

    SciTech Connect

    Vilim, R. B.

    2012-07-31

    A one-dimensional model for a radial inflow turbine has been developed for super-critical carbon dioxide (S-CO{sub 2}) Brayton cycle applications. The model accounts for the main phenomena present in the volute, nozzle, and impeller of a single-stage turbine. These phenomena include internal losses due to friction, blade loading, and angle of incidence and parasitic losses due to windage and blade-housing leakage. The model has been added as a component to the G-PASS plant systems code. The model was developed to support the analysis of S-CO{sub 2} cycles in conjunction with small-scale loop experiments. Such loops operate at less than a MWt thermal input. Their size permits components to be reconfigured in new arrangements relatively easily and economically. However, the small thermal input combined with the properties of carbon dioxide lead to turbomachines with impeller diameters of only one to two inches. At these sizes the dominant phenomena differ from those in larger more typical machines. There is almost no treatment in the literature of turbomachines at these sizes. The present work therefore is aimed at developing turbomachine models that support the task of S-CO{sub 2} cycle analysis using small-scale tests. Model predictions were compared against data from an experiment performed for Sandia National Laboratories in the split-flow Brayton cycle loop currently located at Barber-Nichols Inc. The split-flow loop incorporates two turbo-alternator-compressor (TAC) units each incorporating a radial inflow turbine and a radial flow compressor on a common shaft. The predicted thermodynamic conditions at the outlet of the turbine on the main compressor shaft were compared with measured values at different shaft speeds. Two modifications to the original model were needed to better match the experiment data. First, a representation of the heat loss from the volute downstream of the sensed inlet temperature was added. Second, an empirical multiplicative factor was applied to the Euler head and another to the head loss to bring the predicted outlet pressure into better agreement with the experiment. These changes also brought the overall efficiency of the turbine into agreement with values cited by Barber Nichols for small turbines. More generally, the quality of measurement set data can in the future be improved by additional steps taken in the design and operation of the experimental apparatus. First, a thermocouple mounted at the nozzle inlet would provide a better indication of temperature at this key point. Second, heat losses from the turbine should be measured directly. Allowing the impeller to free wheel at inlet conditions and measuring the temperature drop between inlet and outlet would provide a more accurate measure of heat loss. Finally, the enthalpy change during operation is more accurately obtained by measuring the torque on the stator using strain gauges rather than by measuring pressure and temperature at inlet and outlet to infer thermodynamic states.

  18. Revised FORTRAN program for calculating velocities and streamlines on the hub-shroud midchannel stream surface of an axial-, radial-, or mixed-flow turbomachine or annular duct. 2: Programmer's manual

    NASA Technical Reports Server (NTRS)

    Katsanis, T.; Mcnally, W. D.

    1977-01-01

    A FORTRAN IV computer program has been developed that obtains a detailed subsonic or shock free transonic flow solution on the hub-shroud midchannel stream surface of a turbomachine. The blade row may be fixed or rotating, and the blades may be twisted and leaned. Flow may be axial, mixed, or radial. Upstream and downstream flow variables may vary from hub to shroud, and provisions are made to correct for loss of stagnation pressure. The results include velocities, streamlines, and flow angles on the stream surface and approximate blade surface velocities.

  19. Radial Inflow Turboexpander Redesign

    SciTech Connect

    William G. Price

    2001-09-24

    Steamboat Envirosystems, LLC (SELC) was awarded a grant in accordance with the DOE Enhanced Geothermal Systems Project Development. Atlas-Copco Rotoflow (ACR), a radial expansion turbine manufacturer, was responsible for the manufacturing of the turbine and the creation of the new computer program. SB Geo, Inc. (SBG), the facility operator, monitored and assisted ACR's activities as well as provided installation and startup assistance. The primary scope of the project is the redesign of an axial flow turbine to a radial inflow turboexpander to provide increased efficiency and reliability at an existing facility. In addition to the increased efficiency and reliability, the redesign includes an improved reduction gear design, and improved shaft seal design, and upgraded control system and a greater flexibility of application

  20. Simulations of the Neutral-beam-induced Rotation, Radial Electric Field, and Flow Shearing Rate in Next-step Burning Plasmas

    SciTech Connect

    R.V. Budny

    2002-08-13

    Toroidal rotation of plasmas in present tokamaks is beneficial for increasing the stability to wall-induced MHD and appears to reduce the anomalous transport associated with micro-turbulence. This paper calculates the toroidal rotation expected from neutral-beam injection in the proposed FIRE and ITER-FEAT tokamak reactors. Self-consistent burning plasmas for these tokamaks have been constructed using the TRANSP plasma analysis code. Neutral-beam injection has been proposed for FIRE and ITER-FEAT. The neutral-beam-induced torques are computed, and assumptions for the anomalous transport of toroidal angular momentum are used to calculate the toroidal rotation profiles. The central Mach numbers are about 3-8%. The ratio of the rotation speed to the Alfvin speed is less than 1%. Assuming neoclassical poloidal rotation and force balance, the radial electric field and flow shearing rate are calculated. Peak shearing rates near the outboard edge are in the 10-100 krad/s range.

  1. Measurement of radionuclides using ion chromatography and flow-cell scintillation counting with pulse shape discrimination

    SciTech Connect

    DeVol, T.A.; Fjeld, R.A.; Roane, J.E.; Leyba, J.D.; Branton, S.D.

    1996-12-31

    Principal conclusions are: CsI(Tl) provides sufficient pulse shape discrimination for use in the flow-cell detector. However, an improved method of coating is needed to extend the useful life of a detection cell. Of the activation/fission products investigated, only the co-elution of {sup 137}Cs and {sup 63}Ni produced a radiological interference. Tritium (and presumably other non-ionic radioisotopes) can be separated during the loading of the solution onto the pre- concentration column. Natural U (and/or decay products) produced a radiological interference with {sup 90}Sr. This is a potential problem. No potential radiological interferences were observed with {sup 223}Th. Chemical interferences were observed to some degree for all the chemicals tested except for the chloride solutions, NaCl and KCl, and the sulfate solution, Na{sub 2}SO{sub 4}. The specific interference effects were decreased detection efficiencies and changes in peak elution times. The NEL`s (non-observable effects loadings) are tentative targets for development of sample processing protocols, which is the next phase of the work.

  2. High-pressure size exclusion chromatography analysis of dissolved organic matter isolated by tangential-flow ultra filtration

    USGS Publications Warehouse

    Everett, C.R.; Chin, Y.-P.; Aiken, G.R.

    1999-01-01

    A 1,000-Dalton tangential-flow ultrafiltration (TFUF) membrane was used to isolate dissolved organic matter (DOM) from several freshwater environments. The TFUF unit used in this study was able to completely retain a polystyrene sulfonate 1,800-Dalton standard. Unaltered and TFUF-fractionated DOM molecular weights were assayed by high-pressure size exclusion chromatography (HPSEC). The weight-averaged molecular weights of the retentates were larger than those of the raw water samples, whereas the filtrates were all significantly smaller and approximately the same size or smaller than the manufacturer-specified pore size of the membrane. Moreover, at 280 nm the molar absorptivity of the DOM retained by the ultrafilter is significantly larger than the material in the filtrate. This observation suggests that most of the chromophoric components are associated with the higher molecular weight fraction of the DOM pool. Multivalent metals in the aqueous matrix also affected the molecular weights of the DOM molecules. Typically, proton-exchanged DOM retentates were smaller than untreated samples. This TFUF system appears to be an effective means of isolating aquatic DOM by size, but the ultimate size of the retentates may be affected by the presence of metals and by configurational properties unique to the DOM phase.

  3. On-line flow injection-cloud point preconcentration of polycyclic aromatic hydrocarbons coupled with high-performance liquid chromatography.

    PubMed

    Li, Cheuk Fai; Wong, Jonathan W C; Huie, Carmen W; Choi, Martin M F

    2008-12-19

    Cloud point methodology has been used to develop a novel preconcentration and an analytical method for polycyclic aromatic hydrocarbons (PAHs) in soil sample. The nonionic surfactant Tergitol 15-S-7 was successfully used as the surfactant-mediated extractant in both ultrasonic and microwave-assisted extractions. Over 90% of recoveries for various PAHs in soil were obtained under the optimal experimental conditions. The extracts were then preconcentrated and analyzed by our proposed on-line coupling method "flow injection-cloud point preconcentration-high-performance liquid chromatography" (FI-CPP-HPLC) equipped with a fluorescence detector and an excitation/emission wavelength program. The preconcentration system and optimal working conditions were established. The limit of detection of the FI-CPE-HPLC system ranges from 0.101 to 0.456 microg/L for the selected PAHs, i.e., phenanthrene, pyrene, chrysene, benzo[k]fluoranthene and benzo[a]pyrene. Our proposed technique provides a reliable, simple and automatic analytical method for the determination of PAHs in environmental soil samples. PMID:19004448

  4. On the use of quadrupole mass spectrometric detection for flow modulated comprehensive two-dimensional gas chromatography.

    PubMed

    Gorovenko, Roman; Krup?k, Jn; pnik, Ivan; Bo?kov, Ingrid; Sandra, Pat; Armstrong, Daniel W

    2014-02-21

    Flow modulated comprehensive two-dimensional gas chromatography with simultaneous flame ionization detection (FM GCGC-FID) and quadrupole mass spectrometric detection (FM GCGC-qMSD) was applied to the analysis of a quantitative reference standard sample covering the C5-C14 hydrocarbon range and a kerosene sample. This study reports the influence of the data acquisition frequency (DAF) of the qMSD on the qualitative and quantitative data. The DAF was varied between 5.27 and 25.45Hz. In GCGC-qMSD, the characterization of peaks is getting worse with decreasing qMSD frequencies which deteriorate the quality of the 2D contour plots of the separations. It is, however, demonstrated that the improved characterization of the peaks at high qMSD frequencies is combined with loss in sensitivity and in spectral quality. Dependences of a (2)D hydrocarbon peak area (?Ai of all corresponding (2)D peaks) on the DAFs show negative slopes which testify the conclusion that the sensitivity of GCGC-qMSD determinations decreases with the increase of DAF. Consequently, the limits of detection (LOD) and quantification (LOQ) increase with the increase of DAF. Moreover, quality criteria on recorded spectral data also indicate that the lower the DAF is, the higher is the spectral quality. PMID:24461452

  5. Quantification of Hydroxychloroquine in Blood Using Turbulent Flow Liquid Chromatography-Tandem Mass Spectrometry (TFLC-MS/MS).

    PubMed

    Chambliss, Allison B; Fzry, Anna K; Clarke, William A

    2016-01-01

    Hydroxychloroquine (HQ) is used routinely in the treatment of autoimmune disorders such as rheumatoid arthritis and lupus erythematosus. Issues such as marked pharmacokinetic variability and patient non-compliance make therapeutic drug monitoring of HQ a useful tool for management of patients taking this drug. Quantitative measurements of HQ may aid in identifying poor efficacy as well as provide reliable information to distinguish patient non-compliance from refractory disease. We describe a rapid 7-min assay for the accurate and precise measurement of HQ concentrations in 100 ?L samples of human blood using turbulent flow liquid chromatography coupled to tandem mass spectrometry. HQ is isolated from EDTA whole blood after a simple extraction with its deuterated analog, hydroxychloroquine-d4, in 0.33 M perchloric acid. Samples are then centrifuged and injected onto the TFLC-MS/MS system. Quantification is performed using a nine-point calibration curve that is linear over a wide range (15.7-4000 ng/mL) with precisions of <5 %. PMID:26660186

  6. Flowing atmospheric pressure afterglow combined with laser ablation for direct analysis of compounds separated by thin-layer chromatography.

    PubMed

    Ceg?owski, Micha?; Smoluch, Marek; Reszke, Edward; Silberring, Jerzy; Schroeder, Grzegorz

    2016-01-01

    A thin-layer chromatography-mass spectrometry (TLC-MS) setup for characterization of low molecular weight compounds separated on standard TLC plates has been constructed. This new approach successfully combines TLC separation, laser ablation, and ionization using flowing atmospheric pressure afterglow (FAPA) source. For the laser ablation, a low-priced 445-nm continuous-wave diode laser pointer, with a power of 1W, was used. The combination of the simple, low-budget laser pointer and the FAPA ion source has made this experimental arrangement broadly available, also for small laboratories. The approach was successfully applied for the characterization of low molecular weight compounds separated on TLC plates, such as a mixture of pyrazole derivatives, alkaloids (nicotine and sparteine), and an extract from a drug tablet consisting of paracetamol, propyphenazone, and caffeine. The laser pointer used was capable of ablating organic compounds without the need of application of any additional substances (matrices, staining, etc.) on the TLC spots. The detection limit of the proposed method was estimated to be 35ng/cm(2) of a pyrazole derivative. Graphical abstract Schematic illustration of new TLC-FAPA setup with diode laser ablation. PMID:26563110

  7. Quantification of Docetaxel in Serum Using Turbulent Flow Liquid Chromatography Electrospray Tandem Mass Spectrometry (TFC-HPLC-ESI-MS/MS).

    PubMed

    Crutchfield, Christopher A; Marzinke, Mark A; Clarke, William A

    2016-01-01

    Docetaxel is a second-generation taxane and is used clinically as an anti-neoplastic agent in cancer chemotherapy via an anti-mitotic mechanism. Its efficacy is limited to a narrow therapeutic window. Inappropriately high concentrations may cause erythema, fluid retention, nausea, diarrhea, and neutropenia. As a result, dosing recommendations have changed from high dosage loading every 3 weeks to lower dosage loading weekly. We describe a method that can be used for therapeutic drug monitoring of docetaxel levels using turbulent flow liquid chromatography electrospray tandem mass spectrometry (TFC-HPLC-ESI-MS/MS). The method is rapid, requiring only 6.3 min per analytical run following a simple protein crash. The method requires only 100 μL of serum. Concentrations of docetaxel were quantified by a calibration curve relating the peak-area ratio of docetaxel to a deuterated internal standard (docetaxel-D9). The method was linear from 7.8 to 1000 ng/mL, with imprecision ≤6.2 %. PMID:26660181

  8. Efficient separations of intact proteins using slip-flow with nano-liquid chromatography-mass spectrometry.

    PubMed

    Wu, Zhen; Wei, Bingchuan; Zhang, Ximo; Wirth, Mary J

    2014-02-01

    A capillary with a pulled tip, densely packed with silica particles of 0.47 ?m in diameter, is shown to provide higher peak capacity and sensitivity in the separation of intact proteins by reversed-phase liquid chromatography-mass spectrometry (LC-MS). For a C18 bonded phase, slip flow gave a 10-fold flow enhancement to allow for stable nanospray with a 4-cm column length. Model proteins were studied: ribonuclease A, trypsin inhibitor, and carbonic anhydrase, where the latter had impurities of superoxide dismutase and ubiquitin. The proteins were well separated at room temperature with negligible peak tailing. The peak capacity for ubiquitin was 195 for a 10-min gradient and 315 for a 40-min gradient based on Gaussian fitting of the entire peak, rather than extrapolating the full-width at half-maximum. Separation of a cell lysate with a 60 min gradient showed extremely high peak capacities of 750 and above for a peptide and relatively homogeneous proteins. Clean, low noise mass spectra for each model protein were obtained. The physical widths of the peaks were an order of magnitude narrower than those of conventional columns, giving increased sensitivity. All proteins except ubiquitin exhibited significant heterogeneity apparently due to multiple proteoforms, as indicated by both peak shapes and mass spectra. The chromatograms exhibited excellent reproducibility in retention time, with relative standard deviations of 0.09 to 0.34%. The results indicate that submicrometer particles are promising for improving the separation dimension of LC in top-down proteomics. PMID:24383398

  9. Continuous flow PCB radiolysis with real time assessment by gas chromatography

    SciTech Connect

    Bruce J. Mincher; Aaron Ruhter; Rene' Rodriguez; Richard Brey

    2006-05-01

    Recently, the treatment of environmentally recalcitrant pollutants such as PCBs has been studied using a number of so-called, advanced oxidation technologies (AOTs). As a group, the AOTs are ultimate treatment technologies that seek to mineralize the hazardous compounds to be treated (Cooper et al., 2004). One of the most versatile of the AOTs is radiolysis, usually practiced using machine-generated sources of radiation (Cooper et al., 2004, Mincher and Cooper, 2003). The radiolytic decomposition of PCBs has been reviewed (Curry and Mincher, 1999). While earlier experiments have been performed in alkaline isopropanol (Singh et al., 1985, Mucka et al., 1997), recent literature has begun to examine the radiolysis of PCBs in more real-world solvents, such as transformer oil (Arbon and Mincher, 1996, Mincher et al., 2000, Chaychian et al., 1999). These experiments have generally been performed in batch fashion, with small volumes of PCB-contaminated solvents placed in front of a gamma-ray source or the bremmstrahlung or e-beam of an accelerator for predetermined periods of time, to give a desired absorbed dose. These samples were then retrieved to analyze the post-irradiation PCB concentration. We report here what we believe is the first example of the radiolysis of PCBs in a process, continuous flow stream, as opposed to typical batch irradiations. The PCB-containing transformer oil was recirculated through an irradiation cell located in the path of an e-beam. Multiple passes through the cell allowed for the delivery of any desired radiation dose. This system required the development of an on-line analytical system that could provide PCB concentration values in real time. In the current experiment, a pulsed plasma electron capture detector (PDECD) was used in conjunction with a new sample preparation scheme. The new sampling scheme bypasses the need for removal or powering down of the radiation source, which would be undesirable during process PCB treatment. Dilution of the samples using volumetric glassware or balances at a site remote to the irradiation, and manual injection of the diluted samples in a remote GC is not required. Thus, the error and time delays associated with stopping and restarting the accelerator are eliminated and kinetic investigations are more easily performed. The PCB levels can be determined within a few minutes of delivering a specified dose to the sample while the process stream continues to be irradiated. Additionally, any possible chemical species in the oil with reactive lifetimes on the order of just a few minutes could be observed with this method. It has previously been reported that the addition of alkaline isopropanol spikes to PCB oils has a catalytic effect on PCB decomposition by radiolysis (Mincher et al., 2000, Mincher et al., 2002). Here we report the results of process irradiation of transformer oil contaminated with PCBs for unadulterated oils, and for oils spiked with alkaline isopropanol to decrease the time and dose required for treatment.

  10. Simultaneous determination of aflatoxin B₁, B₂, G₁, and G₂ in corn powder, edible oil, peanut butter, and soy sauce by liquid chromatography with tandem mass spectrometry utilizing turbulent flow chromatography.

    PubMed

    Fan, Sufang; Li, Qiang; Zhang, Xiaoguang; Cui, Xiaobin; Zhang, Dongsheng; Zhang, Yan

    2015-05-01

    A novel fully automated method based on dual column switching using turbulent flow chromatography followed by liquid chromatography with tandem mass spectrometry was developed for the determination of aflatoxin B1 , B2 , G1 , and G2 in corn powder, edible oil, peanut butter, and soy sauce samples. After ultrasound-assisted extraction, samples were directly injected to the chromatographic system and the analytes were concentrated into the clean-up loading column. Through purge switching, the analytes were transferred to the analytical column for subsequent detection by mass spectrometry. Different types of TurboFlow(TM) columns, transfer flow rate, transfer time were optimized. The limits of detection and quantification of this method ranged between 0.2-2.0 and 0.5-4.0 μg/kg for aflatoxins in different matrixes, respectively. Recoveries of aflatoxins were in range of 83-108.1% for all samples, matrix effects were in range of 34.1-104.7%. The developed method has been successfully applied in the analysis of aflatoxin B1 , B2 , G1 , and G2 in real samples. PMID:25683560

  11. Sap flow measurements combining sap-flux density radial profiles with punctual sap-flux density measurements in oak trees (Quercus ilex and Quercus pyrenaica) - water-use implications in a water-limited savanna-

    NASA Astrophysics Data System (ADS)

    Reyes, J. Leonardo; Lubczynski1, Maciek W.

    2010-05-01

    Sap flow measurement is a key aspect for understanding how plants use water and their impacts on the ecosystems. A variety of sensors have been developed to measure sap flow, each one with its unique characteristics. When the aim of a research is to have accurate tree water use calculations, with high temporal and spatial resolution (i.e. scaled), a sensor with high accuracy, high measurement efficiency, low signal-to-noise ratio and low price is ideal, but such has not been developed yet. Granier's thermal dissipation probes (TDP) have been widely used in many studies and various environmental conditions because of its simplicity, reliability, efficiency and low cost. However, it has two major flaws when is used in semi-arid environments and broad-stem tree species: it is often affected by high natural thermal gradients (NTG), which distorts the measurements, and it cannot measure the radial variability of sap-flux density in trees with sapwood thicker than two centimeters. The new, multi point heat field deformation sensor (HFD) is theoretically not affected by NTG, and it can measure the radial variability of the sap flow at different depths. However, its high cost is a serious limitation when simultaneous measurements are required in several trees (e.g. catchment-scale studies). The underlying challenge is to develop a monitoring schema in which HFD and TDP are combined to satisfy the needs of measurement efficiency and accuracy in water accounting. To assess the level of agreement between TDP and HFD methods in quantifying sap flow rates and temporal patterns on Quercus ilex (Q.i ) and Quercus pyrenaica trees (Q.p.), three measurement schemas: standard TDP, TDP-NTG-corrected and HFD were compared in dry season at the semi-arid Sardon area, near Salamanca in Spain in the period from June to September 2009. To correct TDP measurements with regard to radial sap flow variability, a radial sap flux density correction factor was applied and tested by adjusting TDP measurements using the HFD-measured radial profiles. The standard TDP daily mean of sap-flux density was 95% higher than the 2cm equivalent of the HFD for Q. ilex and 70% higher for Q. pyrenaica. NTG-corrected TDP daily mean of sap-flux density was 34% higher than HFD for Q. ilex and 47% lower for Q. pyrenaica. Regarding sap flow measurements, the standard TDP sap flow was 81% higher than HFD sap flow for Q. ilex and 297% for Q. pyrenaica. The NTG-corrected TDP sap flow was 24% higher than HFD sap flow for Q. ilex and 23% for Q. pyrenaica. The radial correction, for TDP-NTG-corrected sap-flux density, produced sap-flow measurements in well agreement with HFD, just slightly lower (-3% Q.i. and -4% Q.p.). The TDP-HFD sap flow data acquired in dry season over the savanna type of sparsely distributed oak trees (Q. ilex & Q. pyrenaica) showed that the TDP method must be corrected for NTG and for radial variability of sap flux density in trees with sapwood thicker than 2 cm. If such corrections are not taken into consideration, the amount of accounted water used by the trees is prone to overestimation, especially for Quercus pyrenaica. The obtained results indicate also that the combination of HFD and TDP leads to an efficient and accurate operational sap flow measurement schema that is currently in the optimization stage.

  12. Preliminary applications of cross-axis synchronous flow-through coil planet centrifuge for large-scale preparative counter-current chromatography.

    PubMed

    Zhang, T Y; Lee, Y W; Fang, Q C; Xiao, R; Ito, Y

    1988-11-11

    The cross-axis synchronous flow-through coil planet centrifuge with a 20-cm revolutional radius and a total capacity of 1600 ml was successfully applied to preparative counter-current chromatography of various biological samples, which include sea buckthorn extract, steroid reaction mixture, indole plant hormones, and dinitrophenylamino acids. The present system offers advantages of stable balance of the centrifuge, a large column capacity, and high resolution. PMID:3069856

  13. Sorption of para-xylene vapors on salt-treated soils measured by flow-equilibration and gas chromatography methods

    SciTech Connect

    Rhue, R.D.; Pennell, K.D.; Reve, W.H.

    1993-07-01

    The impact of soil properties other than organic C content and surface area on vapor-phase sorption has rarely been considered. This study was conducted to determine the effect of salt, namely CaCl{sub 2}, on the sorption of p-xylene vapor under anhydrous and hydrated conditions. Sorption on Webster soil (Typic Haploquolls) before and after removal of organic C was measured using a flow-equilibration method. in addition, the utility of an eluted pulse gas chromatography method was evaluated using the sand fraction of Oldsmar soil (Alfic Arenic Haplaquods) as a column-packing material. The CaCl{sub 2} significantly decreased p-xylene sorption at both 0 and 90% RH for both adsorbents. Under anhydrous conditions, reduced sorption by Oldsmar sand was evidenced at low p-xylene vapor pressures by a constant net retention volume and symmetrical peaks, indicating linear sorption and ideal behavior at these vapor pressures (i.e., the Henry`s region). In the absence of salt, the net retention volume continued to increase at p-xylene vapor pressures as low as 0.33 Pa, indicating isotherm nonlinearity, even at this low vapor pressure. This difference in retention behavior suggests that salt modified the nature of the surface of the sorbents. Under hydrated conditions, the reduction in sorption may be related to the salting-out effect of CaCl{sub 2} on gas solubility in adsorbed water films. These data suggest that the distribution and migration of organic vapors may be substantially greater in salt-affected soils due to reduced sorption on both the dry and water-coated solid phases that am present. 27 refs., 5 figs.

  14. Radial cold trap

    DOEpatents

    Grundy, Brian R. (Greensburg, PA)

    1981-01-01

    The radial cold trap comprises a housing having a plurality of mesh bands disposed therein. The mesh bands comprise concentrically arranged bands of mesh with the mesh specific surface area of each band increasing from the outermost mesh band to the innermost mesh band. An inlet nozzle is attached to the outside section of the housing while an outlet nozzle is attached to the inner portion of the housing so as to be concentrically connected to the innermost mesh band. An inlet baffle having orifices therein may be disposed around the outermost mesh band and within the housing for directing the flow of the fluid from the inlet nozzle to the outermost mesh band in a uniform manner. The flow of fluid passes through each consecutive mesh band and into the outlet nozzle. The circular pattern of the symmetrically arranged mesh packing allows for better utilization of the entire cold trap volume.

  15. Radial cold trap

    DOEpatents

    Grundy, B.R.

    1981-09-29

    The radial cold trap comprises a housing having a plurality of mesh bands disposed therein. The mesh bands comprise concentrically arranged bands of mesh with the mesh specific surface area of each band increasing from the outermost mesh band to the innermost mesh band. An inlet nozzle is attached to the outside section of the housing while an outlet nozzle is attached to the inner portion of the housing so as to be concentrically connected to the innermost mesh band. An inlet baffle having orifices therein may be disposed around the outermost mesh band and within the housing for directing the flow of the fluid from the inlet nozzle to the outermost mesh band in a uniform manner. The flow of fluid passes through each consecutive mesh band and into the outlet nozzle. The circular pattern of the symmetrically arranged mesh packing allows for better utilization of the entire cold trap volume. 2 figs.

  16. Revised FORTRAN program for calculating velocities and streamlines on the hub-shroud midchannel stream surface of an axial-, radial-, or mixed-flow turbomachine or annular duct. 1: User's manual

    NASA Technical Reports Server (NTRS)

    Katsanis, T.; Mcnally, W. D.

    1977-01-01

    A FORTRAN 4 computer program was developed that obtains a detailed subsonic or shock-free transonic flow solution on the hub-shroud midchannel stream surface of a turbomachine. The blade row may be fixed or rotating, and the blades may be twisted and leaned. Flow may be axial, mixed, or radial. Upstream and downstream flow variables may vary from hub to shroud, and provision is made to correct for loss of stagnation pressure. The results include velocities, streamlines, and flow angles on the stream surface as well as approximate blade surface velocities. Subsonic solutions are obtained by a finite-difference, stream-function solution. Transonic solutions are obtained by a velocity-gradient method that uses information from a finite-difference, stream-function solution at a reduced mass flow.

  17. CALIBRATION OF SUBMERGED RADIAL GATES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Calibration equations for free-flowing radial gates typically provide sufficient accuracy for irrigation district operations. However, many districts have difficulty in determining accurate discharges when the downstream water level begins to submerge the gate. Based on laboratory studies, we have d...

  18. Differentiating organically and conventionally grown oregano using ultraperformance liquid chromatography mass spectrometry (UPLC-MS), headspace gas chromatography with flame ionization detection (headspace-GC-FID), and flow injection mass spectrum (FIMS) fingerprints combined with multivariate data analysis.

    PubMed

    Gao, Boyan; Qin, Fang; Ding, Tingting; Chen, Yineng; Lu, Weiying; Yu, Liangli Lucy

    2014-08-13

    Ultraperformance liquid chromatography mass spectrometry (UPLC-MS), flow injection mass spectrometry (FIMS), and headspace gas chromatography (headspace-GC) combined with multivariate data analysis techniques were examined and compared in differentiating organically grown oregano from that grown conventionally. It is the first time that headspace-GC fingerprinting technology is reported in differentiating organically and conventionally grown spice samples. The results also indicated that UPLC-MS, FIMS, and headspace-GC-FID fingerprints with OPLS-DA were able to effectively distinguish oreganos under different growing conditions, whereas with PCA, only FIMS fingerprint could differentiate the organically and conventionally grown oregano samples. UPLC fingerprinting provided detailed information about the chemical composition of oregano with a longer analysis time, whereas FIMS finished a sample analysis within 1 min. On the other hand, headspace GC-FID fingerprinting required no sample pretreatment, suggesting its potential as a high-throughput method in distinguishing organically and conventionally grown oregano samples. In addition, chemical components in oregano were identified by their molecular weight using QTOF-MS and headspace-GC-MS. PMID:25050447

  19. Applying Chromatography.

    ERIC Educational Resources Information Center

    Klein, Jessie W.; Patev, Paul

    1998-01-01

    Presents three experiments to introduce students to different kinds of chromatography: (1) paper chromatography; (2) gel filtration chromatography; and (3) reverse-phase liquid chromatography. Written in the form of a laboratory manual, explanations of each of the techniques, materials needed, procedures, and a glossary are included. (PVD)

  20. On-line stop-flow two-dimensional liquid chromatography-mass spectrometry method for the separation and identification of triterpenoid saponins from ginseng extract.

    PubMed

    Wang, Shuangyuan; Qiao, Lizhen; Shi, Xianzhe; Hu, Chunxiu; Kong, Hongwei; Xu, Guowang

    2015-01-01

    A method based on stop-flow two-dimensional liquid chromatography coupled with electrospray ionization mass spectrometry (2D LC-ESI MS) was established and applied to analyze triterpenoid saponins from the main root of ginseng. Due to the special structure of triterpenoid saponins (they contain polar sugar side chains and nonpolar aglycones), hydrophilic interaction chromatography (HILIC) and reversed-phase liquid chromatography (RPLC) were used for the two dimensions, respectively. A trap column was used to connect the two dimensions. The dilution effect, which is one of the main shortcomings of traditional comprehensive 2D LC methods, was largely avoided. The peak capacity of this system was 747 and the orthogonality was 56.6 %. Compared with one-dimensional HILIC or RP LC MS analysis, 257 and 185 % more mass spectral peaks (ions with intensities that were higher than 1,000) were obtained from the ginseng main root extracts, and 94 triterpenoid saponins were identified based on MS(n) information and summarized aglycone structures. Given its good linearity and repeatability, the established method was successfully applied to classify ginsengs of different ages (i.e., years of growth), and 19 triterpenoid saponins were found through statistical analysis to vary in concentration depending on the age of the ginseng. PMID:25410638

  1. Radial head fracture - aftercare

    MedlinePLUS

    Elbow fracture - radial head - aftercare ... the radius bone, just below your elbow. A fracture is a break in your bone. The most common cause of a radial head fracture is falling with an outstretched arm.

  2. Comparative study of differential flow and cryogenic modulators comprehensive two-dimensional gas chromatography systems for the detailed analysis of light cycle oil.

    PubMed

    Semard, G; Gouin, C; Bourdet, J; Bord, N; Livadaris, V

    2011-05-27

    The modulator is the key point of comprehensive two-dimensional gas chromatography (GCGC). This interface ensures the sampling and transfer of the sample from the first to the second dimension. Many systems based on different principles have been developed. However, to our knowledge, almost only cryogenic modulators are used in the petroleum industry. Nevertheless cryogenic fluids represent some disadvantages in term of safety, cost and time consuming. This paper reports a comparative study between differential flow and cryogenic liquid modulators for the detailed analysis of hydrocarbons in middle distillates type light cycle oil (LCO). Optimization of geometrical dimensions of a set of columns was carried out on the differential flow modulator system in order to reproduce the quality of separation of cryogenic modulation. Then a comparative study was investigated on sensibility and resolution (separation space and peak capacity) between the two systems. PMID:20933237

  3. Rapid determination of 88 veterinary drug residues in milk using automated TurborFlow online clean-up mode coupled to liquid chromatography-tandem mass spectrometry.

    PubMed

    Zhu, Wei-Xia; Yang, Ji-Zhou; Wang, Zhao-Xing; Wang, Cai-Juan; Liu, Ya-Feng; Zhang, Li

    2016-02-01

    A novel method based on TurborFlow online solid phase extraction (SPE) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been established for simultaneous screening and confirmation of 88 wide-range veterinary drugs belonging to eight families (20 sulfonamides, 7 macrolides, 15 quinolones, 8 penicillins, 13 benzimidazoles, 4 tetracyclines, 2 sedatives, and 19 hormones) in milk. The preparation method consists of sample dilution and ultrasonic extraction, followed by an automated turbulent flow cyclone chromatography sample clean-up system. The detection was achieved in selected reaction monitoring mode (SRM). The total run time was within 39min, including automated extraction, analytical chromatography and re-equilibration of the turboflow system. The optimization of different experimental parameters including extraction, purification, separation, and detection were evaluated separately in this study. The developed method was validated and good performing characteristics were obtained. The linear regression coefficients (R(2)) of matrix-match calibration standard curves established for quantification were higher than 0.9930. The limits of detection (LOD) were in the range of 0.2-2.0μg/kg given by signal-noise ratio ≥3 (S/N) and the limits of quantification (LOQ, S/N≥10) ranged between 0.5μg/kg and 10μg/kg. Average recoveries of spiked target compounds with different levels were between 63.1% and 117.4%, with percentage relative standard deviations (RSD) in the range of 3.3-17.6%. The results indicated that the developed method has great potential for the routine laboratory analysis of large numbers of samples on measuring different classes of compounds. In comparison to traditional procedures, the automated sample clean-up ensures rapid, effective, sensitive analyses of veterinary drugs in milk. PMID:26653466

  4. Novel Integrated Radial and Axial Magnetic Bearing

    NASA Technical Reports Server (NTRS)

    Blumenstock, Kenneth A.; Brown, Gary L.; Powers, Edward I. (Technical Monitor)

    2000-01-01

    Typically, fully active magnetically suspended systems require one axial and two radial magnetic bearings. Combining radial and axial functions into a single device allows for more compact and elegant packaging. Furthermore, in the case of high-speed devices such as energy storage flywheels, it is beneficial to minimize shaft length to keep rotor mode frequencies as high as possible. Attempts have been made to combine radial and axial functionality, but with certain drawbacks. One approach requires magnetic control flux to flow through a bias magnet reducing control effectiveness, thus resulting in increased resistive losses. This approach also requires axial force producing magnetic flux to flow in a direction into the rotor laminate that is undesirable for minimizing eddy-current losses resulting in rotational losses. Another approach applies a conical rotor shape to what otherwise would be a radial heteropolar magnetic bearing configuration. However, positional non-linear effects are introduced with this scheme and the same windings are used for bias, radial, and axial control adding complexity to the controller and electronics. For this approach, the amount of axial capability must be limited. It would be desirable for an integrated radial and axial magnetic bearing to have the following characteristics, separate inputs for radial and axial control for electronics and control simplicity, all magnetic control fluxes should only flow through their respective air gaps and should not flow through any bias magnets for minimal resistive losses, be of a homopolar design to minimize rotational losses, position related non-linear effects should be minimized, and dependent upon the design parameters, be able to achieve any radial/axial force or power ratio as desired. The integrated radial and axial magnetic bearing described in this paper exhibits all these characteristics. Magnetic circuit design, design equations, and analysis results will be presented.

  5. Plastic Models Designed to Produce Large Height-to-Length Ratio Steady-State Planar and Axisymmetric (Radial) Viscous Liquid Laminar Flow Gravity Currents

    ERIC Educational Resources Information Center

    Blanck, Harvey F.

    2012-01-01

    Naturally occurring gravity currents include events such as air flowing through an open front door, a volcanic eruption's pyroclastic flow down a mountainside, and the spread of the Bhopal disaster's methyl isocyanate gas. Gravity currents typically have a small height-to-distance ratio. Plastic models were designed and constructed with a

  6. Plastic Models Designed to Produce Large Height-to-Length Ratio Steady-State Planar and Axisymmetric (Radial) Viscous Liquid Laminar Flow Gravity Currents

    ERIC Educational Resources Information Center

    Blanck, Harvey F.

    2012-01-01

    Naturally occurring gravity currents include events such as air flowing through an open front door, a volcanic eruption's pyroclastic flow down a mountainside, and the spread of the Bhopal disaster's methyl isocyanate gas. Gravity currents typically have a small height-to-distance ratio. Plastic models were designed and constructed with a…

  7. Radial artery graft vasospasm.

    PubMed

    Gabe, E D; Figal, J C; Wisner, J N; Laguens, R

    2001-01-01

    We report an unusual case of vasospasm of a grafted radial artery complicated with ventricular fibrillation during the postoperative course of coronary artery bypass graft surgery. To our knowledge this is the first documented case of a radial artery graft spasm leading to a severe arrhythmia. The arrhythmia resolved spontaneously. Radial artery graft spasm was demonstrated by angiography and was successfully resolved by intravenous nitroglycerin administration. PMID:11163573

  8. Radial arm strike rail

    DOEpatents

    McKeown, Mark H. (Golden, CO); Beason, Steven C. (Lakewood, CO)

    1991-01-01

    The radial arm strike rail assembly is a system for measurement of bearings, directions, and stereophotography for geologic mapping, particularly where magnetic compasses are not appropriate. The radial arm, pivoting around a shaft axis, provides a reference direction determination for geologic mapping and bearing or direction determination. The centerable and levelable pedestal provide a base for the radial arm strike rail and the telescoping camera pedestal. The telescoping feature of the radial arm strike rail allows positioning the end of the rail for strike direction or bearing measurement with a goniometer.

  9. Screening for multiple phosphodiesterase type 5 inhibitor drugs in dietary supplement materials by flow injection mass spectrometry and their quantification by liquid chromatography tandem mass spectrometry.

    PubMed

    Song, Fenhong; El-Demerdash, Aref; Lee, Shwn-Ji Susie H

    2012-11-01

    A flow injection tandem mass spectrometry method (FI-MS/MS) has been developed to detect enzyme phosphodiesterase type 5 inhibitors, including tadalafil, sildenafil, and vardenafil. Multiple reaction monitoring (MRM) was used to detect the drugs and product ion ratios were used for identification. FI-MS/MS was used for semi-quantification and liquid chromatography tandem mass spectrometry (LC-MS/MS) was used for further confirmation and quantification. One of 13 samples has been found to be adulterated with prescription levels of tadalafil and also low level of sildenafil. The method can be used for screening large numbers of herbal products for adulteration since it takes less than 1 min without chromatographic separation on a column. PMID:22695818

  10. Triple acting radial seal

    DOEpatents

    Ebert, Todd A; Carella, John A

    2012-03-13

    A triple acting radial seal used as an interstage seal assembly in a gas turbine engine, where the seal assembly includes an interstage seal support extending from a stationary inner shroud of a vane ring, the interstage seal support includes a larger annular radial inward facing groove in which an outer annular floating seal assembly is secured for radial displacement, and the outer annular floating seal assembly includes a smaller annular radial inward facing groove in which an inner annular floating seal assembly is secured also for radial displacement. A compliant seal is secured to the inner annular floating seal assembly. The outer annular floating seal assembly encapsulates the inner annular floating seal assembly which is made from a very low alpha material in order to reduce thermal stress.

  11. Affinity Chromatography.

    ERIC Educational Resources Information Center

    Gray, Gary R.

    1980-01-01

    Presents selected recent advances in immobilization chemistry which have important connections to affinity chromatography. Discusses ligand immobilization and support modification. Cites 51 references. (CS)

  12. Automated on-line renewable solid-phase extraction-liquid chromatography exploiting multisyringe flow injection-bead injection lab-on-valve analysis.

    PubMed

    Quintana, José Benito; Miró, Manuel; Estela, José Manuel; Cerdà, Víctor

    2006-04-15

    In this paper, the third generation of flow injection analysis, also named the lab-on-valve (LOV) approach, is proposed for the first time as a front end to high-performance liquid chromatography (HPLC) for on-line solid-phase extraction (SPE) sample processing by exploiting the bead injection (BI) concept. The proposed microanalytical system based on discontinuous programmable flow features automated packing (and withdrawal after single use) of a small amount of sorbent (<5 mg) into the microconduits of the flow network and quantitative elution of sorbed species into a narrow band (150 microL of 95% MeOH). The hyphenation of multisyringe flow injection analysis (MSFIA) with BI-LOV prior to HPLC analysis is utilized for on-line postextraction treatment to ensure chemical compatibility between the eluate medium and the initial HPLC gradient conditions. This circumvents the band-broadening effect commonly observed in conventional on-line SPE-based sample processors due to the low eluting strength of the mobile phase. The potential of the novel MSFI-BI-LOV hyphenation for on-line handling of complex environmental and biological samples prior to reversed-phase chromatographic separations was assessed for the expeditious determination of five acidic pharmaceutical residues (viz., ketoprofen, naproxen, bezafibrate, diclofenac, and ibuprofen) and one metabolite (viz., salicylic acid) in surface water, urban wastewater, and urine. To this end, the copolymeric divinylbenzene-co-n-vinylpyrrolidone beads (Oasis HLB) were utilized as renewable sorptive entities in the micromachined unit. The automated analytical method features relative recovery percentages of >88%, limits of detection within the range 0.02-0.67 ng mL(-1), and coefficients of variation <11% for the column renewable mode and gives rise to a drastic reduction in operation costs ( approximately 25-fold) as compared to on-line column switching systems. PMID:16615800

  13. Measurement of bromate in bottled water by high-performance liquid chromatography with post-column flow reactor detection.

    PubMed

    Warner, C R; Daniels, D H; Joe, F L; Diachenko, G W

    1996-01-01

    The objective of this work was to develop a reliable, rugged high-performance liquid chromatographic (HPLC) method for determination of trace levels of bromate (< 10 micrograms/l) in bottled water. HPLC separation was achieved by ion interaction chromatography using a C-18 reversed-phase column and a mobile phase consisting of methanol/water (20:80, v/v) with tetrabutylammonium acetate as the ion interaction reagent. A post-column reaction based on oxidation of o-dianisidine in acidic solution to a product detected at 500 nm provided selective measurement of the oxidants. The limit of detection and the limit of quantitation were 1 and 3 micrograms/l, respectively. Iodate, chlorite, and nitrite were chromatographically separated from bromate and measured by monitoring the post-column reaction. Chloride and chlorate at levels that might be found in bottled water did not interfere with the determination of bromate. Bromate was detected in bottled waters at concentrations up to 40 micrograms/l. PMID:8871120

  14. Effects of Radial Variability in Sap Flow on up-Scaling of in Situ Evapotranspiration Measurements from the Scale of Individual Trees to the Grove Scale

    NASA Astrophysics Data System (ADS)

    Quinlan, P. T.; Weinberger, J. L.; Tartakovsky, D. M.

    2014-12-01

    Sap flow sensors are routinely used to obtain in situ measurements of evapotranspiration (ET) by individual trees. Flow rates within a single tree of some species, e.g., Quercus englemanii trees, exhibit high spatial variability. The latter impedes one's ability to extrapolate single-tree ET estimates to their grove- and/or watershed-scale counterparts. A simplistic approach of using the highest observed sap flow rate might introduce a systemic bias into up-scaled estimates. We propose an approach to obtain a representative sap flow rate from all observed data; this rate is then applied to multiple trees in order to extrapolate ET rates from individual trees to the grove-scale. Eight thermal dissipation probe (TDP) pairs were deployed in individual Quercus englemanii trees, which had previously been monitored with only two TDP pairs. Analysis of the variability observed among the probes in the eight-probe arrays yields both a representative composite ET rate for the tree and quantification of the uncertainty associated with that rate. The probability distribution from the eight probe arrays can be applied to trees with one or two probes to estimate the probable range of representative ET rates for those trees and the composite rates for all measured trees is then applied to the grove as a whole.

  15. Determination of histamine in wines with an on-line pre-column flow derivatization system coupled to high performance liquid chromatography.

    PubMed

    García-Villar, Natividad; Saurina, Javier; Hernández-Cassou, Santiago

    2005-09-01

    A new rapid and sensitive high performance liquid chromatography (HPLC) method for determining histamine in red wine samples, based on continuous flow derivatization with 1,2-naphthoquinone-4-sulfonate (NQS), is proposed. In this system, samples are derivatized on-line in a three-channel flow manifold for reagent, buffer and sample. The reaction takes place in a PTFE coil heated at 80 degrees C and with a residence time of 2.9 min. The reaction mixture is injected directly into the chromatographic system, where the histamine derivative is separated from other aminated compounds present in the wine matrix in less than ten minutes. The HPLC procedure involves a C18 column, a binary gradient of 2% acetic acid-methanol as a mobile phase, and UV detection at 305 nm. Analytical parameters of the method are evaluated using red wine samples. The linear range is up to 66.7 mg L(-1) (r = 0.9999), the precision (RSD) is 3%, the detection limit is 0.22 mg L(-1), and the average histamine recovery is 101.5% +/- 6.7%. Commercial red wines from different Spanish regions are analyzed with the proposed method. PMID:16096675

  16. Evaluation of a novel helium ionization detector within the context of (low-)flow modulation comprehensive two-dimensional gas chromatography.

    PubMed

    Franchina, Flavio A; Maimone, Mariarosa; Sciarrone, Danilo; Purcaro, Giorgia; Tranchida, Peter Q; Mondello, Luigi

    2015-07-10

    The present research is focused on the use and evaluation of a novel helium ionization detector, defined as barrier discharge ionization detector (BID), within the context of (low-)flow modulation comprehensive two-dimensional gas chromatography (FM GC×GC). The performance of the BID device was compared to that of a flame ionization detector (FID), under similar FM GC×GC conditions. Following development and optimization of the FM GC×GC method, the BID was subjected to fine tuning in relation to acquisition frequency and discharge flow. Moreover, the BID performance was measured and compared to that of the FID, in terms of extra-column band broadening, sensitivity and dynamic range. The comparative study was carried out by using standard compounds belonging to different chemical classes, along with a sample of diesel fuel. Advantages and disadvantages of the BID system, also within the context of FM GC×GC, are critically discussed. In general, the BID system was characterized by a more limited dynamic range and increased sensitivity, compared to the FID. Additionally, BID and FID contribution to band broadening was found to be similar under the operational conditions applied. Particular attention was devoted to the behaviour of the FM GC×GC-BID system toward saturated and aromatic hydrocarbons, for a possible future use in the field of mineral-oil food contamination research. PMID:26032893

  17. Four-stage (low-)flow modulation comprehensive gas chromatography-quadrupole mass spectrometry for the determination of recently-highlighted cosmetic allergens.

    PubMed

    Tranchida, Peter Q; Maimone, Mariarosa; Franchina, Flavio A; Bjerk, Thiago Rodrigues; Zini, Cláudia Alcaraz; Purcaro, Giorgia; Mondello, Luigi

    2016-03-25

    The present research is based on the development and use of a flow-modulation (FM) comprehensive two-dimensional gas chromatography-quadrupole mass spectrometry (GC×GC-qMS) method for the determination of recently-highlighted (by the Scientific Committee on Consumer Safety) fragrance allergens (54) in cosmetics. FM GC×GC-qMS conditions were finely tuned to generate flow conditions (≈7mLmin(-1)) compatible with the qMS system used. Six-point calibration curves, over the range 1, 5, 10, 20, 50, 100mgL(-1), were constructed for the 54 target allergens, with satisfactory linearity observed in all cases. Absolute quantification was performed by using extracted ions; target analyte identification was performed through measurement of ion ratios (qualifier/quantifier), full-scan MS database matching and the use of linear retention indices. Additional analytical figures of merit subjected to measurement were intra-day repeatability, accuracy at the 25 and 5mgL(-1) levels, and limits of detection and quantification. The number of data points per peak, along with mass spectral skewing, was also subjected to evaluation. Finally, the FM GC×GC-qMS method was used not only for the quantification of target allergens in five commercial perfumes, but also for general qualitative profiling. PMID:26718184

  18. Simultaneous Analysis of Monovalent Anions and Cations with a Sub-Microliter Dead-Volume Flow-Through Potentiometric Detector for Ion Chromatography.

    PubMed

    Dumanli, Rukiye; Attar, Azade; Erci, Vildan; Isildak, Ibrahim

    2016-04-01

    A microliter dead-volume flow-through cell as a potentiometric detector is described in this article for sensitive, selective and simultaneous detection of common monovalent anions and cations in single column ion chromatography for the first time. The detection cell consisted of less selective anion- and cation-selective composite membrane electrodes together with a solid-state composite matrix reference electrode. The simultaneous separation and sensitive detection of sodium (Na(+)), potassium (K(+)), ammonium (NH4 (+)), chloride (Cl(-)) and nitrate (NO3 (-)) in a single run was achieved by using 98% 1.5 mM MgSO4 and 2% acetonitrile eluent with a mixed-bed ion-exchange separation column without suppressor column system. The separation and simultaneous detection of the anions and cations were completed in 6 min at the eluent flow-rate of 0.8 mL/min. Detection limits, at S/N = 3, were ranged from 0.2 to 1.0 µM for the anions and 0.3 to 3.0 µM for the cations, respectively. The developed method was successfully applied to the simultaneous determination of monovalent anions and cations in several environmental and biological samples. PMID:26786906

  19. Periostin, discovered by nano-flow liquid chromatography and mass spectrometry, is a novel marker of diabetic retinopathy

    SciTech Connect

    Takada, Michiya; Ban, Yoshiyuki; Yamamoto, Gou; Ueda, Toshihiko; Saito, Yuta; Nishimura, Eiichi; Fujisawa, Kunimi; Koide, Ryohei; Mizutani, Masakazu; Kozawa, Tadahiko; Shiraishi, Yuji; Bando, Yasuhiko; Tachikawa, Tetsuhiko; Hirano, Tsutomu

    2010-08-20

    Research highlights: {yields} In proliferative membrane and epiretinal membrane specimens, the numbers of proteins are 225 and 154, respectively, and 123 proteins are common to both. {yields} Periostin and thrombospondin-1 proteins are unique to the proliferative membrane specimens. {yields} The expression of periostin is significantly up-regulated in proliferative membrane specimens. -- Abstract: Diabetes can lead to serious microvascular complications including proliferative diabetic retinopathy (PDR), the leading cause of blindness in adults. Recent studies using gene array technology have attempted to apply a hypothesis-generating approach to elucidate the pathogenesis of PDR, but these studies rely on mRNA differences, which may or may not be related to significant biological processes. To better understand the basic mechanisms of PDR and to identify potential new biomarkers, we performed shotgun liquid chromatography (LC)/tandem mass spectrometry (MS/MS) analysis on pooled protein extracts from neovascular membranes obtained from PDR specimens and compared the results with those from non-vascular epiretinal membrane (ERM) specimens. We detected 226 distinct proteins in neovascular membranes and 154 in ERM. Among these proteins, 102 were specific to neovascular membranes and 30 were specific to ERM. We identified a candidate marker, periostin, as well as several known PDR markers such as pigment epithelium-derived factor (PEDF). We then performed RT-PCR using these markers. The expression of periostin was significantly up-regulated in proliferative membrane specimens. Periostin induces cell attachment and spreading and plays a role in cell adhesion. Proteomic analysis by LC/MS/MS, which permits accurate quantitative comparison, was useful in identifying new candidates such as periostin potentially involved in the pathogenesis of PDR.

  20. Gas Chromatography.

    ERIC Educational Resources Information Center

    Karasek, Francis W.; And Others

    1984-01-01

    This review covers fundamental developments in gas chromatography during 1982 and 1983. Literature is considered under these headings: columns; liguid phases; solid supports; sorption processes and solvents; open tubular column gas chromatography; instrumentation; high-resolution columns and applications; other techniques; qualitative and…

  1. Gas Chromatography.

    ERIC Educational Resources Information Center

    Karasek, Francis W.; And Others

    1984-01-01

    This review covers fundamental developments in gas chromatography during 1982 and 1983. Literature is considered under these headings: columns; liguid phases; solid supports; sorption processes and solvents; open tubular column gas chromatography; instrumentation; high-resolution columns and applications; other techniques; qualitative and

  2. Methods and apparatus for radially compliant component mounting

    DOEpatents

    Bulman, David Edward (Cincinnati, OH); Darkins, Jr., Toby George (Loveland, OH); Stumpf, James Anthony (Columbus, IN); Schroder, Mark S. (Greenville, SC); Lipinski, John Joseph (Simpsonville, SC)

    2012-03-27

    Methods and apparatus for a mounting assembly for a liner of a gas turbine engine combustor are provided. The combustor includes a combustor liner and a radially outer annular flow sleeve. The mounting assembly includes an inner ring surrounding a radially outer surface of the liner and including a plurality of axially extending fingers. The mounting assembly also includes a radially outer ring coupled to the inner ring through a plurality of spacers that extend radially from a radially outer surface of the inner ring to the outer ring.

  3. Radial heat flux transformer

    NASA Technical Reports Server (NTRS)

    Basiulis, A.; Buzzard, R. J.

    1971-01-01

    Unit moves heat radially from small diameter shell to larger diameter shell, or vice versa, with negligible temperature drop, making device useful wherever heating or cooling of concentrically arranged materials, substances, and structures is desired.

  4. Dielectrokinetic chromatography devices

    SciTech Connect

    Chirica, Gabriela S; Fiechtner, Gregory J; Singh, Anup K

    2014-12-16

    Disclosed herein are methods and devices for dielectrokinetic chromatography. As disclosed, the devices comprise microchannels having at least one perturber which produces a non-uniformity in a field spanning the width of the microchannel. The interaction of the field non-uniformity with a perturber produces a secondary flow which competes with a primary flow. By decreasing the size of the perturber the secondary flow becomes significant for particles/analytes in the nanometer-size range. Depending on the nature of a particle/analyte present in the fluid and its interaction with the primary flow and the secondary flow, the analyte may be retained or redirected. The composition of the primary flow can be varied to affect the magnitude of primary and/or secondary flows on the particles/analytes and thereby separate and concentrate it from other particles/analytes.

  5. Chiral magnetic microspheres purified by centrifugal field flow fractionation and microspheres magnetic chiral chromatography for benzoin racemate separation

    PubMed Central

    Tian, Ailin; Qi, Jing; Liu, Yating; Wang, Fengkang; Ito, Yoichiro; Wei, Yun

    2013-01-01

    Separation of enantiomers still remains a challenge due to their identical physical and chemical properties in a chiral environment, and the research on specific chiral selector along with separation techniques continues to be conducted to resolve individual enantiomers. In our laboratory the promising magnetic chiral microspheres Fe3O4@SiO2@cellulose-2, 3-bis (3, 5-dimethylphenylcarbamate) have been developed to facilitate the resolution using both its magnetic property and chiral recognition ability. In our present studies this magnetic chiral selector was first purified by centrifuge field flow fractionation, and then used to separate benzoin racemate by a chromatographic method. Uniform-sized and masking-impurity-removed magnetic chiral selector was first obtained by field flow fractionation with ethanol through a spiral column mounted on the type-J planetary centrifuge, and using the purified magnetic chiral selector, the final chromatographic separation of benzoin racemate was successfully performed by eluting with ethanol through a coiled tube (wound around the cylindrical magnet to retain the magnetic chiral selector as a stationary phase) submerged in dry ice. In addition, an external magnetic field facilitates the recycling of the magnetic chiral selector. PMID:23891368

  6. Gas Chromatography.

    ERIC Educational Resources Information Center

    Cram, Stuart P.; And Others

    1980-01-01

    Selects fundamental developments in theory, methodology, and instrumentation in gas chromatography (GC). A special section reviews GC in the People's Republic of China. Over 1,000 references are cited. (CS)

  7. [Approaches to radial shaft].

    PubMed

    Barton?ek, J; Na?ka, O; Tu?ek, M

    2015-10-01

    In the clinical practice, radial shaft may be exposed via two approaches, namely the posterolateral Thompson and volar (anterior) Henry approaches. A feared complication of both of them is the injury to the deep branch of the radial nerve. No consensus has been reached, yet, as to which of the two approaches is more beneficial for the proximal half of radius. According to our anatomical studies and clinical experience, Thompson approach is safe only in fractures of the middle and distal thirds of the radial shaft, but highly risky in fractures of its proximal third. Henry approach may be used in any fracture of the radial shaft and provides a safe exposure of the entire lateral and anterior surfaces of the radius.The Henry approach has three phases. In the first phase, incision is made along the line connecting the biceps brachii tendon and the styloid process of radius. Care must be taken not to damage the lateral cutaneous nerve of forearm.In the second phase, fascia is incised and the brachioradialis identified by the typical transition from the muscle belly to tendon and the shape of the tendon. On the lateral side, the brachioradialis lines the space with the radial artery and veins and the superficial branch of the radial nerve running at its bottom. On the medial side, the space is defined by the pronator teres in the proximal part and the flexor carpi radialis in the distal part. The superficial branch of the radial nerve is retracted together with the brachioradialis laterally, and the radial artery medially.In the third phase, the attachment of the pronator teres is identified by its typical tendon in the middle of convexity of the lateral surface of the radial shaft. The proximal half of the radius must be exposed very carefully in order not to damage the deep branch of the radial nerve. Dissection starts at the insertion of the pronator teres and proceeds proximally along its lateral border in interval between this muscle and insertion of the supinator. During release and retraction of the supinator posterolaterally, it is beneficial to supinate the proximal fragment of the shaft as much as possible, preferably by K-wire drilled perpendicular into the anterior surface of the fragment and rotated externally. As a result, canalis supinatorius is moved posteriorly which reduces the risk of injury to the deep branch of the radial nerve. The supinator is released always from distal to proximal. Approximately at the level of the biceps brachii tendon, it is usually necessary to identify and ligate the radial recurrent artery and vein which prevent retraction of the radial vessels medially. After detachment of the whole supinator, a small Hohmann elevator is carefully inserted between the muscle and the bone. If necessary, it is now possible to open the anterior surface of the joint capsule and revise the humeroradial joint. PMID:26556019

  8. Hyphenation of centrifugal partition chromatography with electrospray ionization mass spectrometry using an active flow-splitter device for characterization of flavonol glycosides.

    PubMed

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

    2009-06-01

    Online coupling of centrifugal partition chromatography to electrospray ionization mass spectrometry (CPC/ESI-MS) was investigated for the separation and characterization of flavonol glycosides. Structural identification and purification monitoring of analytes on milligram scale were demonstrated to be possible by using an active flow-splitter device which transfers automatically and successively, at discrete frequencies, small aliquots of the chromatographic effluent to an independent auxiliary stream directed to an ESI quadrupole mass spectrometer. The CPC protocol used a biphasic solvent system composed of ethyl acetate/ethanol/water (4.5:1:4.5, v/v/v) in isocratic mode. During the separation process, continuous acquisition of mass spectral data of the isolated flavonols from the effluent was performed in the negative ion mode with an auxiliary stream composed of 50 mM ammonium acetate/ethanol (2:8, v/v) delivered by a secondary pump. To demonstrate the potential of this hyphenated technique, flavonol glycosides from an apple peel extract were identified, purified and quantitatively analyzed. Calibration curves and limits of detection are also detailed. PMID:19441050

  9. Flow-modulated comprehensive two-dimensional gas chromatography combined with a high-resolution time-of-flight mass spectrometer: a proof-of-principle study.

    PubMed

    Tranchida, Peter Q; Salivo, Simona; Franchina, Flavio A; Mondello, Luigi

    2015-03-01

    The present research is focused on the evaluation of a recently developed high-resolution time-of-flight mass spectrometer (HR TOF MS), under the challenging conditions of a flow-modulation comprehensive two-dimensional gas chromatography (FM GC GC) experiment. The HR TOF MS instrument was operated at a spectral generation frequency of 30 Hz and a mass resolution of ?25,000 (fwhm). The effluent exiting the second-dimension column was in the range 6-8 mL/min, with part directed to waste to avoid exceeding the maximum pumping capacity of the MS system. An FM GC GC-HR TOF MS method was developed for the untargeted and targeted analysis of a sample of high complexity, namely, heavy gas oil. With regard to the untargeted results, these were satisfactory in relation to MS database searching and mass accuracies. Considering the targeted data, the high selectivity of the MS system was highlighted by the use of accurate mass extracted-ion-chromatograms with narrow mass windows (5 and 1 ppm), for specific classes of polyaromatic sulfur heterocycles (PASHs), namely, benzothiophenes and dibenzothiophenes. Finally, the instrumental performance was also evaluated through the injection of standard solutions of four classes of PASHs. PMID:25642594

  10. Theoretical evaluation of the advantages and limitations of constant pressure versus constant flow rate gradient elution separation in supercritical fluid chromatography.

    PubMed

    De Pauw, Ruben; Desmet, Gert; Broeckhoven, Ken

    2013-10-18

    This study reports on the possible advantages of switching from constant flow (cF) based gradient elution separations to constant pressure (cP) based ones in Supercritical fluid chromatography (SFC) by means of mathematical models. All the important parameters (e.g. viscosity) were fitted as a function of pressure and mol% methanol in CO2. It is shown that when switching towards a cP approach in SFC, a time gain of 34% at the end of a 0 to 50% methanol in CO2 gradient is expected. Actual analysis time gains depend on the point at which it is evaluated (e.g. up to 41% after the equilibration step). Due to the dependence of retention on density, cF- and cP-mode do not yield the same selectivity even if the same volumetric-based gradient program is used. Because the components experience a higher average pressure in the cP-mode, the apparent retention factor is slightly lower. PMID:24041511

  11. Determination of aromatic sulphur compounds in heavy gas oil by using (low-)flow modulated comprehensive two-dimensional gas chromatography-triple quadrupole mass spectrometry.

    PubMed

    Franchina, Flavio Antonio; Machado, Maria Elisabete; Tranchida, Peter Quinto; Zini, Cláudia Alcaraz; Caramão, Elina Bastos; Mondello, Luigi

    2015-03-27

    The present research is focused on the development of a flow-modulated comprehensive two-dimensional gas chromatography-triple quadrupole mass spectrometry (FM GC × GC-MS/MS) method for the determination of classes of aromatic organic sulphur compounds (benzothiophenes, dibenzothiophenes, and benzonaphthothiophene) in heavy gas oil (HGO). The MS/MS instrument was used to provide both full-scan and multiple-reaction-monitoring (MRM) data. Linear retention index (LRI) ranges were used to define the MRM windows for each chemical class. Calibration solutions (internal standard: 1-fluoronaphthalene) were prepared by using an HGO sample, depleted of S compounds. Calibration information was also derived for the thiophene class (along with MRM and LRI data), even though such constituents were not present in the HGO. Linearity was satisfactory over the analyzed concentration range (1-100 mg/L); intra-day precision for the lowest calibration point was always below 17%. Accuracy was also satisfactory, with a maximum percentage error of 3.5% (absolute value) found among the S classes subjected to (semi-)quantification. The highest limit of quantification was calculated to be 299 μg/L (for the C1-benzothiophene class), while the lowest was 21 μg/L (for the C4-benzothiophene class). PMID:25704775

  12. Development of a multiplex flow-through immunoaffinity chromatography test for the on-site screening of 14 sulfonamide and 13 quinolone residues in milk.

    PubMed

    Jiang, Wenxiao; Beloglazova, Natalia V; Wang, Zhanhui; Jiang, Haiyang; Wen, Kai; de Saeger, Sarah; Luo, Pengjie; Wu, Yongning; Shen, Jianzhong

    2015-04-15

    In this paper, a rapid and sensitive multiplex flow-through immunoaffinity chromatography test (FTIACT) was developed for the on-site screening of 14 sulfonamide and 13 quinolone residues in milk. The developed FTIACT method combines the purification, preconcentration and immunochemical detection of multiple antibiotics on the sepharose gel test layers. The use of liposome-encapsulated quantum dots (LQDs) with the FTIACT method exhibited the best results, with limits of detection (LODs) of 1 and 0.5ng/mL for the sulfonamides (SAs) and quinolones (QNs), respectively, through qualitative analysis (visual detection by the naked eye). In order to achieve low detection limit, the color intensity of the images were converted into relative optical density values to enable a quantitative evaluation. Quantitative analysis of the samples enabled the detection of SAs (0.13ng/mL) and QNs (0.062ng/mL) in spiked milk samples. The FTIACT described in this work shows promise as a multiplex immunoassay for the qualitative and quantitative screening of multiple chemical residues in milk. PMID:25460892

  13. A novel strategy for the discrimination of gelatinous Chinese medicines based on enzymatic digestion followed by nano-flow liquid chromatography in tandem with orbitrap mass spectrum detection

    PubMed Central

    Yang, Huan; Shen, Yuping; Xu, Ying; Maqueda, Aida Serra; Zheng, Jie; Wu, Qinan; Tam, James P

    2015-01-01

    Gelatinous Chinese medicines made from mammalian skin or horn or reptile shell are a very important type of animal-derived Chinese medicine. They have been extensively used either as both hemopoietic and hemostatic agents to treat vertigo, palpitation, hematuria, and insomnia in traditional Chinese medicine clinics; consumed as a popular tonic for weaker persons such as the elderly or women after giving birth; or further manufactured to health supplements for certain populations. However, they cannot be discriminated from each other by only using the routine approach in the Chinese Pharmacopoeia, as it lacks enough specificity and, consequently, and the requirements can be met even by adding assayed ingredients. In this study, our efforts to differentiate three gelatinous Chinese medicines, Asini Corii Colla, Cervi Cornus Colla, and Testudinis Carapacis ET Plastri Colla, are presented, and a novel strategy based on enzymatic digestion followed by nano-flow liquid chromatography in tandem with orbitrap mass spectrum detector analysis is proposed herein. Fourteen diagnostic fragments identified from the digests of these medicines were exclusively selected for their discrimination. By taking advantage of the favorable features of this strategy, it is feasible and convenient to identify enzymatic-digested peptides originated from signature proteins in each medicine, which thus could be employed as potential biomarkers for their form of raw medicinal material, and the pulverized and the complex especially, that being the direct basis for authentication purpose. PMID:26345994

  14. Conversion of propan-2-ol on zeolites LaNaY and HY investigated by gas chromatography and in situ MAS NMR spectroscopy under continuous-flow conditions

    SciTech Connect

    Hunger, M.; Horvath, T.

    1997-04-01

    The conversion of propan-2-ol on zeolites HY and LaNaY has been investigated by gas chromatography (GC) and in situ {sup 1}H and {sup 13}C MAS NMR spectroscopy under continuous-flow conditions using a new MAS NMR microreactor with cylindrical catalyst bed. At reaction temperatures of T = 373 K and T = 393 K a propan-2-ol conversion of 50 and 100%, respectively, and the formation of propene, diisopropyl. ether, and small amounts of acetone was determined by GC. Applying in situ {sup 1}H and {sup 13}C MAS NMR spectroscopy, the initial step of the reaction was found to be the physisorption of propan-2-ol on Bronsted acid sites. A formation of isopropoxy species could be excluded by {sup 13}C MAS NMR spectroscopy. {sup 1}H MAS NMR spectroscopy indicated that the Bronsted acid sites of the zeolites LaNaY and HY were hydrated by water molecules in the first part of the induction period. These water molecules were formed in result of the propan-2-ol dehydration. The strong low-field shift of the {sup 1}H MAS NMR signals of the hydrated Bronsted acid sites is due to a partial protonation of adsorbed water molecules. At T = 393 K, a significant {sup 13}C MAS NMR signal of strongly bonded acetone molecules appeared at 220 ppm in the spectra of zeolites LaNaY and HY. As demonstrated by propan-2-ol conversion on a partially dealuminated zeolite HY, this by-reaction is promoted by extra-framework aluminium species. The formation of coke precursors which caused {sup 13}C MAS NMR signals at 10-50 ppm is explained by an oligomerization of propene. In situ {sup 13}C MAS NMR experiments carried out under a continuous flow of propene showed that the above-mentioned coke precursors are also formed on partially rehydrated zeolite HY. 25 refs., 14 figs., 1 tab.

  15. Simultaneous determination of Cr(III) and Cr(VI) in tannery wastewater using low pressure ion chromatography combined with flow injection spectrophotometry.

    PubMed

    Chen, Shujuan; Zhang, Xinshen; Yu, Lingyun; Wang, Li; Li, Hui

    2012-03-01

    Trivalent and hexavalent chromium have been successfully separated and determined using low pressure ion chromatography combined with flow injection spectrophotometric analysis (LPIC-FIA). A column packed with crosslinking starch microspheres was used for on-line separation of Cr(III) from Cr(VI) in a flow-injection system because of its absorptive effect on Cr(III). To determine the concentration of Cr(III) and Cr(VI) in samples, we used 3.0 mmol/L nitric acid to elute adsorbed Cr(III) from the column and then used ceric sulfate-sulfuric acid as oxidant to convert all Cr(III) into Cr(VI). Then, Cr(VI) directly came from the samples and Cr(VI) came from Cr(III) successively formed a amaranthine complex with diphenycarbazide and the complex shows a maximum absorption at 530 nm. Analytical parameters including the concentration of eluent and oxidant solution, oxidizing temperature, length of oxidizing reaction coil, reaction coil and injection coil, interfering effects, etc., were optimized. The limit of detection was 1.25 ?g/L for Cr(VI) and 3.76 ?g/L for Cr(III). The linear relationship between absorption with the concentration of Cr(VI) and Cr(III) was 0.001-1.000 mg/L and 0.030-1.000 mg/L with correlation coefficients of 0.9995 and 0.9994, respectively. The relative standard deviation of Cr(VI) and Cr(III) was 1.21% and 1.66%, respectively (n=10). Major cations and anions did not show any interference. We validated this method through certified reference materials and through measuring the recovery in tannery wastewater. PMID:22209249

  16. Simultaneous determination of Cr(III) and Cr(VI) in tannery wastewater using low pressure ion chromatography combined with flow injection spectrophotometry

    NASA Astrophysics Data System (ADS)

    Chen, Shujuan; Zhang, Xinshen; Yu, Lingyun; Wang, Li; Li, Hui

    2012-03-01

    Trivalent and hexavalent chromium have been successfully separated and determined using low pressure ion chromatography combined with flow injection spectrophotometric analysis (LPIC-FIA). A column packed with crosslinking starch microspheres was used for on-line separation of Cr(III) from Cr(VI) in a flow-injection system because of its absorptive effect on Cr(III). To determine the concentration of Cr(III) and Cr(VI) in samples, we used 3.0 mmol/L nitric acid to elute adsorbed Cr(III) from the column and then used ceric sulfate-sulfuric acid as oxidant to convert all Cr(III) into Cr(VI). Then, Cr(VI) directly came from the samples and Cr(VI) came from Cr(III) successively formed a amaranthine complex with diphenycarbazide and the complex shows a maximum absorption at 530 nm. Analytical parameters including the concentration of eluent and oxidant solution, oxidizing temperature, length of oxidizing reaction coil, reaction coil and injection coil, interfering effects, etc., were optimized. The limit of detection was 1.25 μg/L for Cr(VI) and 3.76 μg/L for Cr(III). The linear relationship between absorption with the concentration of Cr(VI) and Cr(III) was 0.001-1.000 mg/L and 0.030-1.000 mg/L with correlation coefficients of 0.9995 and 0.9994, respectively. The relative standard deviation of Cr(VI) and Cr(III) was 1.21% and 1.66%, respectively (n = 10). Major cations and anions did not show any interference. We validated this method through certified reference materials and through measuring the recovery in tannery wastewater.

  17. NEW CALIBRATION PROCEDURE FOR SUBMERGED RADIAL GATES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Calibration equations for free-flowing radial gates typically provide sufficient accuracy for irrigation district operations. However, many districts have difficulty in determining accurate discharges when the downstream water level begins to submerge the gate. Based on laboratory studies, we have d...

  18. Radial turbine cooling

    NASA Technical Reports Server (NTRS)

    Roelke, Richard J.

    1992-01-01

    Radial turbines have been used extensively in many applications including small ground based electrical power generators, automotive engine turbochargers and aircraft auxiliary power units. In all of these applications the turbine inlet temperature is limited to a value commensurate with the material strength limitations and life requirements of uncooled metal rotors. To take advantage of all the benefits that higher temperatures offer, such as increased turbine specific power output or higher cycle thermal efficiency, requires improved high temperature materials and/or blade cooling. Extensive research is on-going to advance the material properties of high temperature superalloys as well as composite materials including ceramics. The use of ceramics with their high temperature potential and low cost is particularly appealing for radial turbines. However until these programs reach fruition the only way to make significant step increases beyond the present material temperature barriers is to cool the radial blading.

  19. High-Performance Liquid Chromatography

    NASA Astrophysics Data System (ADS)

    Reuhs, Bradley L.; Rounds, Mary Ann

    High-performance liquid chromatography (HPLC) developed during the 1960s as a direct offshoot of classic column liquid chromatography through improvements in the technology of columns and instrumental components (pumps, injection valves, and detectors). Originally, HPLC was the acronym for high-pressure liquid chromatography, reflecting the high operating pressures generated by early columns. By the late 1970s, however, high-performance liquid chromatography had become the preferred term, emphasizing the effective separations achieved. In fact, newer columns and packing materials offer high performance at moderate pressure (although still high pressure relative to gravity-flow liquid chromatography). HPLC can be applied to the analysis of any compound with solubility in a liquid that can be used as the mobile phase. Although most frequently employed as an analytical technique, HPLC also may be used in the preparative mode.

  20. Design of a microfluidic device for comprehensive spatial two-dimensional liquid chromatography.

    PubMed

    Wouters, Bert; De Vos, Jelle; Desmet, Gert; Terryn, Herman; Schoenmakers, Peter J; Eeltink, Sebastiaan

    2015-04-01

    This study discusses the design aspects for the construction of a microfluidic device for comprehensive spatial two-dimensional liquid chromatography. In spatial two-dimensional liquid chromatography each peak is characterized by its coordinates in the plane. After completing the first-dimension separation all fractions are analyzed in parallel second-dimension separations. Hence, spatial two-dimensional liquid chromatography potentially provides much higher peak-production rates than a coupled column multi-dimensional liquid chromatography approach in which the second-dimension analyses are performed sequentially. A chip for spatial two-dimensional liquid chromatography has been manufactured from cyclic olefin copolymer and features a first-dimension separation channel and 21 parallel second-dimension separation channels oriented perpendicularly to the former. Compartmentalization of first- and second-dimension developments by physical barriers allowed for a preferential flow path with a minimal dispersion into the second-dimension separation channels. To generate a homogenous flow across all the parallel second-dimension channels, a radially interconnected flow distributor containing two zones of diamond-shaped pillars was integrated on-chip. A methacrylate ester based monolithic stationary phase with optimized macroporous structure was created in situ in the confines of the microfluidic chip. In addition, the use of a photomask was explored to localize monolith formation in the parallel second-dimension channels. Finally, to connect the spatial chip to the liquid chromatography instrument, connector ports were integrated allowing the use of Viper fittings. As an alternative, a chip holder with adjustable clasp locks was designed that allows the clamping force to be adjusted. PMID:25598051

  1. Radial Halbach Magnetic Bearings

    NASA Technical Reports Server (NTRS)

    Eichenberg, Dennis J.; Gallo, Christopher A.; Thompson, William K.

    2009-01-01

    Radial Halbach magnetic bearings have been investigated as part of an effort to develop increasingly reliable noncontact bearings for future high-speed rotary machines that may be used in such applications as aircraft, industrial, and land-vehicle power systems and in some medical and scientific instrumentation systems. Radial Halbach magnetic bearings are based on the same principle as that of axial Halbach magnetic bearings, differing in geometry as the names of these two types of bearings suggest. Both radial and axial Halbach magnetic bearings are passive in the sense that unlike most other magnetic bearings that have been developed in recent years, they effect stable magnetic levitation without need for complex active control. Axial Halbach magnetic bearings were described in Axial Halbach Magnetic Bearings (LEW-18066-1), NASA Tech Briefs, Vol. 32, No. 7 (July 2008), page 85. In the remainder of this article, the description of the principle of operation from the cited prior article is recapitulated and updated to incorporate the present radial geometry. In simplest terms, the basic principle of levitation in an axial or radial Halbach magnetic bearing is that of the repulsive electromagnetic force between (1) a moving permanent magnet and (2) an electric current induced in a stationary electrical conductor by the motion of the magnetic field. An axial or radial Halbach bearing includes multiple permanent magnets arranged in a Halbach array ("Halbach array" is defined below) in a rotor and multiple conductors in the form of wire coils in a stator, all arranged so the rotary motion produces an axial or radial repulsion that is sufficient to levitate the rotor. A basic Halbach array (see Figure 1) consists of a row of permanent magnets, each oriented so that its magnetic field is at a right angle to that of the adjacent magnet, and the right-angle turns are sequenced so as to maximize the magnitude of the magnetic flux density on one side of the row while minimizing it on the opposite side. The advantage of this configuration is that it makes it possible to approach the theoretical maximum force per unit area that could be exerted by a given amount of permanent-magnet material. The configuration is named after physicist Klaus Halbach, who conceived it for use in particle accelerators. Halbach arrays have also been studied for use in magnetic-levitation ("maglev") railroad trains. In a radial Halbach magnetic bearing, the basic Halbach arrangement is modified into a symmetrical arrangement of sector-shaped permanent magnets mounted on the outer cylindrical surface of a drum rotor (see Figure 2). The magnets are oriented to concentrate the magnetic field on their radially outermost surface. The stator coils are mounted in a stator shell surrounding the rotor.

  2. Radial inflow gas turbine engine with advanced transition duct

    SciTech Connect

    Wiebe, David J

    2015-03-17

    A gas turbine engine (10), including: a turbine having radial inflow impellor blades (38); and an array of advanced transition combustor assemblies arranged circumferentially about the radial inflow impellor blades (38) and having inner surfaces (34) that are adjacent to combustion gases (40). The inner surfaces (34) of the array are configured to accelerate and orient, for delivery directly onto the radial inflow impellor blades (38), a plurality of discrete flows of the combustion gases (40). The array inner surfaces (34) define respective combustion gas flow axes (20). Each combustion gas flow axis (20) is straight from a point of ignition until no longer bound by the array inner surfaces (34), and each combustion gas flow axis (20) intersects a unique location on a circumference defined by a sweep of the radial inflow impellor blades (38).

  3. Gas Chromatography

    NASA Astrophysics Data System (ADS)

    Qian, Michael C.; Peterson, Devin G.; Reineccius, Gary A.

    The first publication on gas chromatography (GC) was in 1952 (1), while the first commercial instruments were manufactured in 1956. James and Martin (1) separated fatty acids by GC, collected the column effluent, and titrated the individual fatty acids for quantitation. GC has advanced greatly since that early work and is now considered to be a mature field that is approaching theoretical limitations.

  4. Gas chromatography

    SciTech Connect

    Willett, J.

    1987-01-01

    This book includes discussions of chemical equilibria, the properties of solutions and gases, the structures of molecules and how they attract one another. It assumes basic knowledge of chemistry and electricity. This book also provides a basic understanding of gas chromatography in a flexible format.

  5. Variable stator radial turbine

    NASA Technical Reports Server (NTRS)

    Rogo, C.; Hajek, T.; Chen, A. G.

    1984-01-01

    A radial turbine stage with a variable area nozzle was investigated. A high work capacity turbine design with a known high performance base was modified to accept a fixed vane stagger angle moveable sidewall nozzle. The nozzle area was varied by moving the forward and rearward sidewalls. Diffusing and accelerating rotor inlet ramps were evaluated in combinations with hub and shroud rotor exit rings. Performance of contoured sidewalls and the location of the sidewall split line with respect to the rotor inlet was compared to the baseline. Performance and rotor exit survey data are presented for 31 different geometries. Detail survey data at the nozzle exit are given in contour plot format for five configurations. A data base is provided for a variable geometry concept that is a viable alternative to the more common pivoted vane variable geometry radial turbine.

  6. Radial pressure flange seal

    DOEpatents

    Batzer, Thomas H. (Livermore, CA); Call, Wayne R. (Tracy, CA)

    1989-01-01

    This invention provides an all metal seal for vacuum or pressure vessels or systems. This invention does not use gaskets. The invention uses a flange which fits into a matching groove. Fluid pressure is applied in a chamber in the flange causing at least one of the flange walls to radially press against a side of the groove creating the seal between the flange wall and the groove side.

  7. Radial pressure flange seal

    DOEpatents

    Batzer, T.H.; Call, W.R.

    1989-01-24

    This invention provides an all metal seal for vacuum or pressure vessels or systems. This invention does not use gaskets. The invention uses a flange which fits into a matching groove. Fluid pressure is applied in a chamber in the flange causing at least one of the flange walls to radially press against a side of the groove creating the seal between the flange wall and the groove side. 5 figs.

  8. Radial Field Piezoelectric Diaphragms

    NASA Technical Reports Server (NTRS)

    Bryant, R. G.; Effinger, R. T., IV; Copeland, B. M., Jr.

    2002-01-01

    A series of active piezoelectric diaphragms were fabricated and patterned with several geometrically defined Inter-Circulating Electrodes "ICE" and Interdigitated Ring Electrodes "ICE". When a voltage potential is applied to the electrodes, the result is a radially distributed electric field that mechanically strains the piezoceramic along the Z-axis (perpendicular to the applied electric field). Unlike other piezoelectric bender actuators, these Radial Field Diaphragms (RFDs) strain concentrically yet afford high displacements (several times that of the equivalent Unimorph) while maintaining a constant circumference. One of the more intriguing aspects is that the radial strain field reverses itself along the radius of the RFD while the tangential strain remains relatively constant. The result is a Z-deflection that has a conical profile. This paper covers the fabrication and characterization of the 5 cm. (2 in.) diaphragms as a function of poling field strength, ceramic thickness, electrode type and line spacing, as well as the surface topography, the resulting strain field and displacement as a function of applied voltage at low frequencies. The unique features of these RFDs include the ability to be clamped about their perimeter with little or no change in displacement, the environmentally insulated packaging, and a highly repeatable fabrication process that uses commodity materials.

  9. Comparison of cryogenic and differential flow (forward and reverse fill/flush) modulators and applications to the analysis of heavy petroleum cuts by high-temperature comprehensive gas chromatography.

    PubMed

    Duhamel, Chloé; Cardinael, Pascal; Peulon-Agasse, Valérie; Firor, Roger; Pascaud, Laurent; Semard-Jousset, Gaëlle; Giusti, Pierre; Livadaris, Vincent

    2015-03-27

    The development of new efficient conversion processes to transform heavy petroleum fractions into valuable products, such as diesel, requires improved chemical knowledge of the latter. High-temperature comprehensive gas chromatography (HT-GC × GC) has proven to be a powerful technique for characterizing such complex samples. This paper reports on an evaluation of the performances of four different differential flow modulators, including two original ones that have not been previously described in the literature, in terms of dispersion, peak intensity, peak capacity and overloading. These modulators, all of which are based on Agilent capillary flow technology (CFT), are forward fill/flush (FFF) differential flow modulators with an integrated collection channel or an adjustable channel (new) and reverse fill/flush (RFF) differential flow modulators with an integrated collection channel (new) or an adjustable channel. First, the optimization of the collection channel dimensions is described. Second, an RFF and an FFF differential flow modulator possessing the same collection channel were compared. The reverse differential flow modulation significantly reduced band broadening compared to forward differential flow modulation, and the peak intensity doubled for every modulated peak when an RFF differential flow modulator was used. Then, an RFF differential flow modulator and CO2 dual-jet modulator were compared. Whereas the percentages of separation space used were similar (61% with the HT-GC × GC method using a cryogenic modulator and 59% with the method using an RFF differential flow modulator), the peak capacities were at least three times more important with differential flow modulation due to the greater length of the column used in the second dimension. The results demonstrate that the RFF differential flow modulator is an excellent tool for studying heavy petroleum cuts. It demonstrates the best performances and it is the most versatile modulator. In its two-plate version, it gives more flexibility regarding the set of columns, the flow rates and the modulation periods that can be used compared with the others. PMID:25704768

  10. The radial-velocity revolution

    NASA Astrophysics Data System (ADS)

    Griffin, Roger

    1989-09-01

    Instruments and techniques designed for registering the minute Doppler shifts arising from stellar radial velocity are examined. Particular attention is given to the photographic spectrographs, the high-dispersion spectrographs ('digital speedometers'), and the Palomar spectrometer. The principle of using radial-velocity masks is described, and the use of interferometers for radial-velocity measurements is discussed. Results are presented of radial velocity observations for HD 114762, HD 210647, and Epsilon Tauri, together with interpretations of these results.

  11. Spiral Countercurrent Chromatography

    PubMed Central

    Ito, Yoichiro; Knight, Martha; Finn, Thomas M.

    2013-01-01

    For many years, high-speed countercurrent chromatography conducted in open tubing coils has been widely used for the separation of natural and synthetic compounds. In this method, the retention of the stationary phase is solely provided by the Archimedean screw effect by rotating the coiled column in the centrifugal force field. However, the system fails to retain enough of the stationary phase for polar solvent systems such as the aqueousaqueous polymer phase systems. To address this problem, the geometry of the coiled channel was modified to a spiral configuration so that the system could utilize the radially acting centrifugal force. This successfully improved the retention of the stationary phase. Two different types of spiral columns were fabricated: the spiral disk assembly, made by stacking multiple plastic disks with single or four interwoven spiral channels connected in series, and the spiral tube assembly, made by inserting the tetrafluoroethylene tubing into a spiral frame (spiral tube support). The capabilities of these column assemblies were successfully demonstrated by separations of peptides and proteins with polar two-phase solvent systems whose stationary phases had not been well retained in the earlier multilayer coil separation column for high-speed countercurrent chromatography. PMID:23833207

  12. Navier-Stokes analysis of radial turbine rotor performance

    NASA Technical Reports Server (NTRS)

    Larosiliere, L. M.

    1993-01-01

    An analysis of flow through a radial turbine rotor using the three-dimensional, thin-layer Navier-Stokes code RVC3D is described. The rotor is a solid version of an air-cooled metallic radial turbine having thick trailing edges, shroud clearance, and scalloped-backface clearance. Results are presented at the nominal operating condition using both a zero-clearance model and a model simulating the effects of the shroud and scalloped-backface clearance flows. A comparison with the available test data is made and details of the internal flow physics are discussed, allowing a better understanding of the complex flow distribution within the rotor.

  13. Improved quantification of livestock associated odorous volatile organic compounds in a standard flow-through system using solid-phase microextraction and gas chromatography-mass spectrometry.

    PubMed

    Yang, Xiuyan; Zhu, Wenda; Koziel, Jacek A; Cai, Lingshuang; Jenks, William S; Laor, Yael; Leeuwen, J Hans van; Hoff, Steven J

    2015-10-01

    Aerial emissions of odorous volatile organic compounds (VOCs) are an important nuisance factor from livestock production systems. Reliable air sampling and analysis methods are needed to develop and test odor mitigation technologies. Quantification of VOCs responsible for livestock odor remains an analytical challenge due to physicochemical properties of VOCs and the requirement for low detection thresholds. A new air sampling and analysis method was developed for testing of odor/VOCs mitigation in simulated livestock emissions system. A flow-through standard gas generating system simulating odorous VOCs in livestock barn emissions was built on laboratory scale and tested to continuously generate ten odorous VOCs commonly defining livestock odor. Standard VOCs included sulfur VOCs (S-VOCs), volatile fatty acids (VFAs), and p-cresol. Solid-phase microextraction (SPME) was optimized for sampling of diluted odorous gas mixtures in the moving air followed by gas chromatography-mass spectrometry (GC-MS) analysis. CAR/PDMS 85?m fiber was shown to have the best sensitivity for the target odorous VOCs. A practical 5-min sampling time was selected to ensure optimal extraction of VFAs and p-cresol, as well as minimum displacement of S-VOCs. Method detection limits ranged from 0.39 to 2.64ppbv for S-VOCs, 0.23 to 0.77ppbv for VFAs, and 0.31ppbv for p-cresol. The method developed was applied to quantify VOCs and odorous VOC mitigation with UV light treatment. The measured concentrations ranged from 20.1 to 815ppbv for S-VOCs, 10.3 to 315ppbv for VFAs, and 4.73 to 417ppbv for p-cresol. Relative standard deviations between replicates ranged from 0.67% to 12.9%, 0.50% to 11.4%, 0.83% to 5.14% for S-VOCs, VFAs, and p-cresol, respectively. This research shows that a simple manual SPME sampler could be used successfully for quantification of important classes of odorous VOCs at concentrations relevant for real aerial emissions from livestock operations. PMID:26456221

  14. Radial cutting torch

    SciTech Connect

    Robertson, M.C.

    1997-01-08

    The project`s aim is to complete development of the Radial Cutting Torch, a pyrotechnic cutter, for use in all downhole tubular cutting operations in the petroleum industry. Project objectives are to redesign and pressure test nozzle seals to increase product quality, reliability, and manufacturability; improve the mechanical anchor to increase its temperature tolerance and its ability to function in a wider variety of wellbore fluids; and redesign and pressure test the RCT nozzle for operation at pressures from 10 to 20 ksi. The proposal work statement is included in the statement of work for the grant via this reference.

  15. Radial Reflection diffraction tomorgraphy

    DOEpatents

    Lehman, Sean K

    2013-11-19

    A wave-based tomographic imaging method and apparatus based upon one or more rotating radially outward oriented transmitting and receiving elements have been developed for non-destructive evaluation. At successive angular locations at a fixed radius, a predetermined transmitting element can launch a primary field and one or more predetermined receiving elements can collect the backscattered field in a "pitch/catch" operation. A Hilbert space inverse wave (HSIW) algorithm can construct images of the received scattered energy waves using operating modes chosen for a particular application. Applications include, improved intravascular imaging, bore hole tomography, and non-destructive evaluation (NDE) of parts having existing access holes.

  16. Radial reflection diffraction tomography

    DOEpatents

    Lehman, Sean K.

    2012-12-18

    A wave-based tomographic imaging method and apparatus based upon one or more rotating radially outward oriented transmitting and receiving elements have been developed for non-destructive evaluation. At successive angular locations at a fixed radius, a predetermined transmitting element can launch a primary field and one or more predetermined receiving elements can collect the backscattered field in a "pitch/catch" operation. A Hilbert space inverse wave (HSIW) algorithm can construct images of the received scattered energy waves using operating modes chosen for a particular application. Applications include, improved intravascular imaging, bore hole tomography, and non-destructive evaluation (NDE) of parts having existing access holes.

  17. Harvesting the radial artery

    PubMed Central

    Osterday, Robert M.; Brodman, Richard F.

    2013-01-01

    The radial artery (RA) has emerged as an important arterial graft for coronary bypass surgery. With improving five-year patency rates and increasing uptake, great attention has been focused on the optimal conduit harvesting technique. We herein present our approach to RA harvesting. Prerequisites of a successful harvest include adherence to important anatomical landmarks, protection of the sensory innervation to the volar forearm, and meticulous handling of the RA branches. Regardless of the harvesting methodology chosen, adherence to a no-touch technique will optimize the patency and durability of the RA conduit. PMID:23977633

  18. Experimental feasibility study of radial injection cooling of three-pad radial air foil bearings

    NASA Astrophysics Data System (ADS)

    Shrestha, Suman K.

    Air foil bearings use ambient air as a lubricant allowing environment-friendly operation. When they are designed, installed, and operated properly, air foil bearings are very cost effective and reliable solution to oil-free turbomachinery. Because air is used as a lubricant, there are no mechanical contacts between the rotor and bearings and when the rotor is lifted off the bearing, near frictionless quiet operation is possible. However, due to the high speed operation, thermal management is one of the very important design factors to consider. Most widely accepted practice of the cooling method is axial cooling, which uses cooling air passing through heat exchange channels formed underneath the bearing pad. Advantage is no hardware modification to implement the axial cooling because elastic foundation structure of foil bearing serves as a heat exchange channels. Disadvantage is axial temperature gradient on the journal shaft and bearing. This work presents the experimental feasibility study of alternative cooling method using radial injection of cooling air directly on the rotor shaft. The injection speeds, number of nozzles, location of nozzles, total air flow rate are important factors determining the effectiveness of the radial injection cooling method. Effectiveness of the radial injection cooling was compared with traditional axial cooling method. A previously constructed test rig was modified to accommodate a new motor with higher torque and radial injection cooling. The radial injection cooling utilizes the direct air injection to the inlet region of air film from three locations at 120 from one another with each location having three axially separated holes. In axial cooling, a certain axial pressure gradient is applied across the bearing to induce axial cooling air through bump foil channels. For the comparison of the two methods, the same amount of cooling air flow rate was used for both axial cooling and radial injection. Cooling air flow rate was referenced to the rotor surface speed for radial injection cooling. The mass flow rates for the radial injection were 0.032, 0.0432, 0.054 and 0.068 Kg/min, which result in average injection speed of 150, 200, 250 and 300% of rotor surface speed. Several thermocouples were attached at various circumferential directions of the bearing sleeve, two plenums, bearing holder and ball bearing housings to collect the temperature data of the bearing at 30krpm under 10lb of load. Both axial cooling and radial injection are effective cooling mechanism and effectiveness of both cooling methods is directly proportional to the total mass flow rates. However, axial cooling is slightly more efficient in controlling the average temperature of the bearing sleeve, but results in higher thermal gradient of the shaft along the axial direction and also higher thermal gradient of the bearing sleeve along the circumferential direction compared to the radial injection cooling. The smaller thermal gradient of the radial injection cooling is due to the direct cooling effect of the shaft by impinging jets. While the axial cooling has an effect on only the bearing, the radial injection has a cooling effect on both the bearing sleeve and shaft. It is considered the radial injection cooling needs to be further optimized in terms of number of injection holes and their locations.

  19. Radial reflection diffraction tomography

    NASA Astrophysics Data System (ADS)

    Lehman, Sean K.; Norton, Stephen J.

    2004-10-01

    A wave-based tomographic imaging algorithm based upon a single rotating radially outward oriented transducer is developed. At successive angular locations at a fixed radius, the transducer launches a primary field and collects the backscattered field in a ``pitch/catch'' operation. The hardware configuration, operating mode, and data collection method are identical to that of most medical intravascular ultrasound (IVUS) systems. IVUS systems form images of the medium surrounding the probe based upon ultrasonic B scans, using a straight-ray model of sound propagation. The goal of this research is to develop a wave-based imaging algorithm using diffraction tomography techniques. Given the hardware configuration and the imaging method, this system is referred to as ``radial reflection diffraction tomography.'' Two hardware configurations are considered: a multimonostatic mode using a single transducer as described above, and a multistatic mode consisting of a single transmitter and an aperture formed by multiple receivers. In this latter case, the entire source/receiver aperture rotates about the fixed radius. Practically, such a probe is mounted at the end of a catheter or snaking tube that can be inserted into a part or medium with the goal of forming images of the plane perpendicular to the axis of rotation. An analytic expression for the multimonostatic inverse is derived, but ultimately the new Hilbert space inverse wave (HSIW) algorithm is used to construct images using both operating modes. Applications include improved IVUS imaging, bore hole tomography, and nondestructive evaluation (NDE) of parts with existing access holes. .

  20. Rebirth of left radial artery access: could this be the 'right' radial artery?

    PubMed

    Taylor, Montoya; Capers, Quinn; Patel, Dilesh; Mehta, Nishaki K

    2015-06-01

    Cardiac catheterization has several risks, notably which include bleeding, stroke and death. The transradial (TR) approach to catheterization is associated with a lower bleeding risk. The right radial approach is the default method in most laboratories and the left radial artery (LRA) serves as the bail-out approach. This article discusses the advantages and disadvantages of transfemoral and TR access routes. The authors envisage an increased adoption of the LRA approach, due to the anatomical superiority and ease of catheter engagement afforded by this approach. The authors discuss ways to increase operator ease for LRA in the laboratory and propose a novel way to improve LRA work-flow. PMID:26000561

  1. COMMISSION 30: Radial Velocities*

    NASA Astrophysics Data System (ADS)

    Nordström, Birgitta; Udry, Stephane; Dravins, D.; Fekel, F.; Glushkova, E.; Levato, H.; Pourbaix, D.; Smith, M. A.; Szabados, L.; Torres, G.

    2007-03-01

    This report from Commission 30 covers the salient areas in which major progress has been made in the triennium covered by the present volume. The principal scientific areas are: The Milky Way, star clusters, spectroscopic binaries, extrasolar planets, pulsating stars and stellar oscillations. Following these, an account is given of the progress in techniques and methodology for radial velocity determinations. Finally, a summary is given of the progress made by the working groups of the Commission, followed by a list of key papers in the triennium. A more extensive report also covering extragalactic work, which due to unforeseen circumstances could not be included here, can be found at the web page of Commission 30 (http://www.iau.org/IAU/Organization/divcom/).

  2. Gas Chromatography

    NASA Astrophysics Data System (ADS)

    Qian, Michael C.

    Gas chromatography (GC) has many applications in the analysis of food products. GC has been used for the determination of fatty acids, triglycerides, cholesterol, gases, water, alcohols, pesticides, flavor compounds, and many more. While GC has been used for other food components such as sugars, oligosaccharides, amino acids, peptides, and vitamins, these substances are more suited to analysis by high performance liquid chromatography. GC is ideally suited to the analysis of volatile substances that are thermally stable. Substances such as pesticides and flavor compounds that meet these criteria can be isolated from a food and directly injected into the GC. For compounds that are thermally unstable, too low in volatility, or yield poor chromatographic separation due to polarity, a derivatization step must be done before GC analysis. The two parts of the experiment described here include the analysis of alcohols that requires no derivatization step, and the analysis of fatty acids which requires derivatization. The experiments specify the use of capillary columns, but the first experiment includes conditions for a packed column.

  3. Radial gate hoist mechanisms mounted above radial gates, view to ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Radial gate hoist mechanisms mounted above radial gates, view to the east - Wellton-Mohawk Irrigation System, Wasteway No. 1, Wellton-Mohawk Canal, North side of Wellton-Mohawk Canal, bounded by Gila River to North & the Union Pacific Railroad & Gila Mountains to south, Wellton, Yuma County, AZ

  4. Vortex rings in radially confined domains

    NASA Astrophysics Data System (ADS)

    Stewart, Kelley C.; Vlachos, Pavlos P.

    2012-10-01

    The dynamics of vortex rings generated within confined domains are relevant to important hydrodynamic processes such as flow past heart valves or severe arterial constrictions. However, despite their importance, these flows have not received much attention to date. This study examines the development and evolution of radially confined vortex rings. Time-resolved digital particle image velocimetry was used to investigate two levels of radial confinement and a range of vortex ring strengths. We found that for severely confined vortex rings, the formation time and peak circulation values were unaffected for L/D 0 < 4 cases and slightly affected for larger L/D 0 cases. After pinch-off, circulation decay was observed with an approximately constant normalized circulation decay rate. We found that with increasing circulation strength, the nondimensional time delay between the pinch-off and the onset of circulation decay reduced due to an increased vortex ring diameter within the confinement domain and a reduction in the necessary time for the surface induced and core vorticity regions to interact. This study uncovers the dynamics of radially confined vortex rings and show that the nondimensional rate of circulation decay is dependent on the vortex ring confinement ratio (ratio of the vortex ring orifice diameter to the diameter of the outer cylinder), and the time delay between the vortex pinch-off and the onset of circulation is dependent on the vortex ring circulation strength.

  5. Fundamentals of preparative and nonlinear chromatography

    SciTech Connect

    Guiochon, Georges A; Felinger, Attila; Katti, Anita; Shirazi, Dean G

    2006-02-01

    The second edition of Fundamentals of Preparative and Nonlinear Chromatography is devoted to the fundamentals of a new process of purification or extraction of chemicals or proteins widely used in the pharmaceutical industry and in preparative chromatography. This process permits the preparation of extremely pure compounds satisfying the requests of the US Food and Drug Administration. The book describes the fundamentals of thermodynamics, mass transfer kinetics, and flow through porous media that are relevant to chromatography. It presents the models used in chromatography and their solutions, discusses the applications made, describes the different processes used, their numerous applications, and the methods of optimization of the experimental conditions of this process.

  6. Atomic Force Microscope Mediated Chromatography

    NASA Technical Reports Server (NTRS)

    Anderson, Mark S.

    2013-01-01

    The atomic force microscope (AFM) is used to inject a sample, provide shear-driven liquid flow over a functionalized substrate, and detect separated components. This is demonstrated using lipophilic dyes and normal phase chromatography. A significant reduction in both size and separation time scales is achieved with a 25-micron-length column scale, and one-second separation times. The approach has general applications to trace chemical and microfluidic analysis. The AFM is now a common tool for ultra-microscopy and nanotechnology. It has also been demonstrated to provide a number of microfluidic functions necessary for miniaturized chromatography. These include injection of sub-femtoliter samples, fluidic switching, and sheardriven pumping. The AFM probe tip can be used to selectively remove surface layers for subsequent microchemical analysis using infrared and tip-enhanced Raman spectroscopy. With its ability to image individual atoms, the AFM is a remarkably sensitive detector that can be used to detect separated components. These diverse functional components of microfluidic manipulation have been combined in this work to demonstrate AFM mediated chromatography. AFM mediated chromatography uses channel-less, shear-driven pumping. This is demonstrated with a thin, aluminum oxide substrate and a non-polar solvent system to separate a mixture of lipophilic dyes. In conventional chromatographic terms, this is analogous to thin-layer chromatography using normal phase alumina substrate with sheardriven pumping provided by the AFM tip-cantilever mechanism. The AFM detection of separated components is accomplished by exploiting the variation in the localized friction of the separated components. The AFM tip-cantilever provides the mechanism for producing shear-induced flows and rapid pumping. Shear-driven chromatography (SDC) is a relatively new concept that overcomes the speed and miniaturization limitations of conventional liquid chromatography. SDC is based on a sliding plate system, consisting of two flat surfaces, one of which has a recessed channel. A fluid flow is produced by axially sliding one plate past another, where the fluid has mechanical shear forces imposed at each point along the channel length. The shear-induced flow rates are very reproducible, and do not have pressure or voltage gradient limitations. SDC opens up a new range of enhanced separation kinetics by permitting the sample confinement with submicron dimensions. Small, highly confined liquid is advantageous for chromatographic separation because the separation rate is known to scale according to the square of the confined sample diameter. In addition, because shear-driven flows are not limited by fluid velocity, shear-driven liquid chromatography may provide up to 100,000 plate efficiency.

  7. Development and validation of two LC-MS/MS methods for the detection and quantification of amphetamines, designer amphetamines, benzoylecgonine, benzodiazepines, opiates, and opioids in urine using turbulent flow chromatography.

    PubMed

    Schaefer, Nadine; Peters, Benjamin; Schmidt, Peter; Ewald, Andreas H

    2013-01-01

    In the context of driving ability diagnostics in Germany, administrative cutoffs for various drugs and pharmaceuticals in urine have been established. Two liquid chromatography-tandem mass spectrometry methods for simultaneous detection and quantification of amphetamines, designer amphetamines, benzoylecgonine, benzodiazepines, opiates, and opioids in urine were developed and validated. A 500-?L aliquot of urine was diluted and fortified with an internal standard solution. After enzymatic cleavage, online extraction was performed by an ion-exchange/reversed-phase turbulent flow column. Separation was achieved by using a reversed-phase column and gradient elution. For detection, a Thermo Fisher TSQ Quantum Ultra Accurate Mass tandem mass spectrometer with positive electrospray ionization was used, and the analytes were measured in multiple-reaction monitoring mode detecting two transitions per precursor ion. The total run time for both methods was about 15 min. Validation was performed according to the guidelines of the Society of Toxicological and Forensic Chemistry. The results of matrix effect determination were between 78% and 116%. The limits of detection and quantification for all drugs, except zopiclone, were less than 10 ng/mL and less than 25 ng/mL, respectively. Calibration curves ranged from 25 to 200 ng/mL for amphetamines, designer amphetamines, and benzoylecgonine, from 25 to 250 ng/mL for benzodiazepines, from 12.5 to 100 ng/mL for morphine, codeine, and dihydrocodeine, and from 5 to 50 ng/mL for buprenorphine and norbuprenorphine. Intraday and interday precision values were lower than 15%, and bias values within 15% were achieved. Turbulent flow chromatography needs no laborious sample preparation, so the workup is less time-consuming compared with gas chromatography-mass spectrometry methods. The methods are suitable for quantification of multiple analytes at the cutoff concentrations required for driving ability diagnostics in Germany. PMID:23076398

  8. Dielectrokinetic chromatography and devices thereof

    DOEpatents

    Chirica, Gabriela S; Fiechtner, Gregory J; Singh, Anup K

    2014-04-22

    Disclosed herein are methods and devices for dielectrokinetic chromatography. As disclosed, the devices comprise microchannels having at least one perturber which produces a non-uniformity in a field spanning the width of the microchannel. The interaction of the field non-uniformity with a perturber produces a secondary flow which competes with a primary flow. By decreasing the size of the perturber the secondary flow becomes significant for particles/analytes in the nanometer-size range. Depending on the nature of a particle/analyte present in the fluid and its interaction with the primary flow and the secondary flow, the analyte may be retained or redirected. The composition of the primary flow can be varied to affect the magnitude of primary and/or secondary flows on the particles/analytes and thereby separate and concentrate it from other particles/analytes.

  9. Atomic force microscope mediated chromatography

    NASA Astrophysics Data System (ADS)

    Anderson, M. S.

    2013-02-01

    An atomic force microscope (AFM) is presented as an instrument for rapid, miniaturized chromatography. The AFM is used to inject a sample, provide shear driven liquid flow over a functionalized substrate, and detect separated components. The components are then analyzed with surface enhanced Raman spectroscopy using AFM deposition of gold nanoparticles on the separated bands. This AFM mediated chromatography (AFM-MC) is demonstrated using lipophilic dyes and normal phase chemistry. A significant reduction in both size and separation time scales is achieved with 25 μm length scale and 1 s separation times. AFM-MC has general applications to trace chemical analysis and microfluidics.

  10. Expanded-bed adsorption chromatography.

    PubMed

    Kennedy, Robert M

    2005-06-01

    Expanded-bed adsorption (EBA) chromatography is a convenient and effective technique for the capture of proteins directly from unclarified crude sample. In EBA chromatography, the settled bed is first expanded by upward flow of equilibration buffer. The crude feed, a mixture of soluble proteins, contaminants, cells, and cell debris, is then passed upward through the expanded bed. Target proteins are captured on the adsorbent, while particulates and contaminants pass through. A change to elution buffer while maintaining upward flow results in desorption of the target protein in expanded-bed mode. Alternatively, if the flow is reversed, the adsorbed particles will quickly settle and the proteins can be desorbed by an elution buffer. The mode used for elution (expanded-bed versus settled-bed) depends on the characteristics of the feed. After elution, the adsorbent is cleaned with a predefined cleaning-in-place (CIP) solution, with cleaning followed by either column regeneration (for further use) or storage. PMID:18429292

  11. Instrumentation: Ion Chromatography.

    ERIC Educational Resources Information Center

    Fritz, James S.

    1987-01-01

    Discusses the importance of ion chromatography in separating and measuring anions. The principles of ion exchange are presented, along with some applications of ion chromatography in industry. Ion chromatography systems are described, as well as ion pair and ion exclusion chromatography, column packings, detectors, and programming. (TW)

  12. Increasing the operating efficiency of radial reactors in reforming

    SciTech Connect

    Lobanov, E.L.; Skipin, Yu.A.

    1987-01-01

    The operating efficiency of a radial reactor is determined by how completely the volume of catalyst is utilized which depends on the uniformity of GFM (gas-feed mixture) flow distribution through the catalyst bed and on whether stagnant zones are present. The authors have performed an operating test on radial reactors in three modern commercial units of the LCh-35-11/600 type. The nonuniformity of the velocity field in the catalyst bed was evaluated from the readings of multizone thermocouples positioned in the bed. It is shown that a relatively uniform distribution of the flow is obtained only in the lower part of the catalyst bed.

  13. The identification and quantification of a high molecular weight light stabilizer in polycarbonate by application of an online coupling of size exclusion chromatography in stopped flow mode with pyrolysis gas chromatography time of flight mass spectroscopy.

    PubMed

    Brander, Eric; Wold, Christian

    2014-10-01

    The identification and quantification of a high molecular weight light stabilizer (Uvinul 3030) in an unknown polycarbonate sample was achieved through the application of SEC-Py-TOF-GCMS. A size exclusion column optimized to achieve resolution in the lower mass range was applied to allow the fractionation of an individual additive peak. A commercially available sampling interface was operated in stop flow mode and fractions were pyrolyzed to allow chromatographic separation of the fragments of the otherwise non-volatile stabilizer. After identification on the basis of accurate mass and elemental composition of the additive the quantification was compared using the available SEC-UV and SEC-PY-GC-TOFMS data. The resulting method provided a high degree of certainty in identification and flexibility in quantification expected to be applicable to other additives of similar volatilities or functional class. PMID:25160954

  14. Erosion in radial inflow turbines. Volume 3: Trajectories of erosive particles in radial inflow turbines

    NASA Technical Reports Server (NTRS)

    Clevenger, W. B., Jr.; Tabakoff, W.

    1974-01-01

    The theoretical trajectories that erosive particles follow in the gas flow fields of a typical radial inflow turbine were investigated. A discussion of the theoretical trajectories that the particles follow in the scroll, in the nozzles, in the vortex between the nozzles and the rotor, and in the rotor passages is included. The results are presented in terms of the characteristic length, a similarity parameter which relates the particles that follow the same trajectory in equivalent flow fields. For Vol, 1, see N74-19395.

  15. A new approach to live reaction monitoring using active flow technology in ultra-high-speed HPLC with mass spectral detection.

    PubMed

    Kocic, Danijela; Andrew Shalliker, R

    2015-12-01

    A new type of chromatography column referred to as a parallel segmented flow (PSF) column enables ultra-high-speed high-performance liquid chromatography-MS to be undertaken. This occurs because the separation efficiency obtained on PSF columns has been shown in prior studies to be superior to conventional columns, and the flow stream is split radially inside the outlet end fitting of the column, rather than in an axial post-column flow stream split. As a result, the flow through the column can be five times higher than the flow through the MS. In this work, the degradation of amino acids in dilute nitric acid was used to illustrate the process. Separations were obtained in less than 12?s, although the reinjection process was initiated 6?s after the previous injection. The degradation rate constant of tryptophan, in the presence of tyrosine and phenylalanine, was determined. Copyright 2015 John Wiley & Sons, Ltd. PMID:26634974

  16. Effect of parallel segmented flow chromatography on the height equivalent to a theoretical plate II - performances of 4.6mm30mm columns packed with 2.6?m Accucore-C18 superficially porous particles.

    PubMed

    Gritti, Fabrice; Guiochon, Georges

    2013-11-01

    The reduced trans-column (or long-range eddy dispersion) height equivalent to a theoretical plate (HETP) of short and wide 4.6mm30mm columns packed with 2.6?m Accucore-C18 superficially porous particles was measured under conventional (no split flow) and parallel segmented (outlet and inlet) flow chromatography. The overall reduced HETP was derived from the true moments of the recorded concentration profiles. The longitudinal diffusion HETP term was measured at a very small flow rate (0.05mL/min). The solid-liquid mass transfer resistance was derived from the shell diffusivity, using the composite Garnett-Torquato model of effective diffusion in a heterogeneous system made of a dense packing of core-shell particles immersed in a continuous matrix (the eluent). The trans-channel and short-range interchannel eddy dispersion HETP terms were assumed to be equal to the calculated h data after solving the Navier-Stokes equation and simulating the advection-diffusion transport process. Experimental results confirmed that the optimum efficiency of these short columns was increased by a factor of about two. The ratio of the detection sensitivities on the PSFC stream and on a regular stream increased from 1 to 1.45 when the retention factor decreases from about 10 to 0.5. These phenomena are due to a strong reduction of the trans-column eddy dispersion HETP term. The system loses about 60% of the sample mass when only outlet skimming is carried out when the flow rate ratio of 55% is applied, as was done in this work. It loses about 50% of the sample when inlet/outlet segmentation is applied. In gradient elution, the peak capacity is increased by only 15%, due to post-column band spreading, which should imperatively be minimized when the outlet flow is split. PMID:24050598

  17. Asymmetric Flow Field Flow Fractionation of Aqueous C60 Nanoparticles with Size Determination by Dynamic Light Scattering and Quantification by Liquid Chromatography Atmospheric Pressure Photo-Ionization Mass Spectrometry

    EPA Science Inventory

    A size separation method was developed for aqueous C60 fullerene aggregates (aqu/C60) using asymmetric flow field flow fractionation (AF4) coupled to a dynamic light scattering detector in flow through mode. Surfactants, which are commonly used in AF4, were avoided as they may al...

  18. Numerical calculation and analysis of radial force on the single-action vane pump

    NASA Astrophysics Data System (ADS)

    Y He, Y.; Y Kong, F.

    2013-12-01

    Unbalanced radial force is a serious adversity that restricts the working pressure and reduces service life of the single-action vane pump. For revealing and predicting the distribution of radial force on the rotor, a numerical simulation about its transient flow field was performed by using dynamic mesh method with RNG ? ?-turbulent model. The details of transient flow characteristic and pressure fluctuation were obtained, and the radial force and periodic variation can be calculated based on the details. The results show: the radial force has a close relationship with the pressure pulsation; the radial force can be reduced drastically by optimizing the angle of port plate and installing the V-shaped cavity; if the odd number vanes are chosen, it will help reduce the radial force of rotor and optimize the pressure fluctuation effectively.

  19. Gas turbine engine with radial diffuser and shortened mid section

    SciTech Connect

    Charron, Richard C.; Montgomery, Matthew D.

    2015-09-08

    An industrial gas turbine engine (10), including: a can annular combustion assembly (80), having a plurality of discrete flow ducts configured to receive combustion gas from respective combustors (82) and deliver the combustion gas along a straight flow path at a speed and orientation appropriate for delivery directly onto the first row (56) of turbine blades (62); and a compressor diffuser (32) having a redirecting surface (130, 140) configured to receive an axial flow of compressed air and redirect the axial flow of compressed air radially outward.

  20. Report: Affinity Chromatography.

    ERIC Educational Resources Information Center

    Walters, Rodney R.

    1985-01-01

    Supports, affinity ligands, immobilization, elution methods, and a number of applications are among the topics considered in this discussion of affinity chromatography. An outline of the basic principles of affinity chromatography is included. (JN)

  1. An Automated Method for the Determination of Trimebutine and N-Mono-Desmethyl Trimebutine by On-Line Turbulent Flow Coupled with Liquid Chromatography-Tandem Mass Spectrometry in Human Plasma: Application to a Fatal Poisoning Case with Toxicokinetic Study.

    PubMed

    Larabi, Islam Amine; Duverneuil-Mayer, Charlotte; Abe, Emuri; Baud, Frdric; Alvarez, Jean-Claude

    2015-11-01

    A liquid chromatography-MS-MS turbulent flow on-line extraction method was developed for the determination of trimebutine (TMB) and its main active metabolite N-mono-desmethyltrimebutine (nortrimebutine or nor-TMB) in human plasma. After protein precipitation and internal standard (IS, haloperidol-d4) addition, 50 L of the supernatant were transferred onto a Cyclone-Turbo-Flow extraction column followed by an Hypersil PFP Gold analytical column. Detection was carried out on a triple quadrupole tandem mass spectrometer using positive electrospray ionization. The transitions used were m/z 388.0?343.0, 374.0?195.0 and 380.1?169.0 for TMB, nor-TMB and IS, respectively. The method was validated over the concentration range of 10-1,000 ng/mL for both compounds. The accuracy evaluated at three concentrations was within 90.0-98.5% and the intra- and interday coefficient of variation's for the two molecules were <8.7%. The method was applied to a toxicokinetic study of a self-poisoning case with TMB in a 19-old girl. The concentration of TMB decreased from 747 to 77 ng/mL, while nor-TMB decreased from 9,745 to 205 ng/mL after 5 days and the fatal issue. This case confirms the literature underlining the potential toxicity of TMB, which has long time been considered as a harmless molecule. PMID:26342056

  2. Erosion in radial inflow turbines. Volume 2: Balance of centrifugal and radial drag forces on erosive particles

    NASA Technical Reports Server (NTRS)

    Clevenger, W. B., Jr.; Tabakoff, W.

    1974-01-01

    The particle motion in two-dimensional free and forced inward flowing vortices is considered. A particle in such a flow field experiences a balance between the aerodynamic drag forces that tend to drive erosive particles toward the axis, and centrifugal forces that prevent these particles from traveling toward the axis. Results predict that certain sizes of particles will achieve a stable orbit about the turbine axis in the inward flowing free vortex. In this condition, the radial drag force is equal to the centrifugal force. The sizes of particles that will achieve a stable orbit is shown to be related to the gas flow velocity diagram at a particular radius. A second analysis yields a description of particle sizes that will experience a centrifugal force that is greater than the radial component of the aerodynamic drag force for a more general type of particle motion.

  3. Chromatography: concepts and contrasts

    SciTech Connect

    Miller, J.M.

    1988-01-01

    As the author states in the Preface, this text attempts to provide a unified approach to chromatography (hence the title) by way of contrasting similarities and differences between gas chromatography (GC), column liquid chromatography (LC), and thin-layer chromatography (TLC). This book is also said to be pitched at an elementary level, suitable for most newcomers to the field (e.g., advanced undergraduates and beginning graduate students in the academic world, as well as bench-level chemists in industry).

  4. CRC handbook of chromatography

    SciTech Connect

    Qureshi, M.

    1986-01-01

    This book provides technology for routine analysis or developing new methods of chromatography or organic materials. In this book Section 1 presents the principles, techniques, quantitative determinations and detection methods used in chromatographic analysis. In the major part of the book, Section 2 summarizes data in voluminous tabular/graphic form on paper, thin layer, liquid and gas chromatography. Section 3 lists important books on electrophoreses, gel permeation chromatography, and ion exchange, in addition to the other forms of chromatography.

  5. Effect of rotor meridional velocity ratio on response to inlet radial and circumferential distortion

    NASA Technical Reports Server (NTRS)

    Sanger, N. L.

    1979-01-01

    Three single transonic fan stages, each having a different meridional velocity ratio across its rotor, were tested with two magnitudes of tip radial distortion and with a 90 deg circumferential distortion imposed on the inlet flow. The rotor with the lowest meridional velocity ratio (less than 0.9 at the tip) demonstrated the least degradation of performance due to these distortions. Loss and deviation angle data (as needed for performance prediction with radial distortion) calculated along actual streamlines for radially distorted flow and correlated against diffusion factor, showed consistent agreement with data calculated along design streamlines for undistorted flow.

  6. Effects of radial motion on interchange injections at Saturn

    NASA Astrophysics Data System (ADS)

    Paranicas, C.; Thomsen, M. F.; Achilleos, N.; Andriopoulou, M.; Badman, S. V.; Hospodarsky, G.; Jackman, C. M.; Jia, X.; Kennelly, T.; Khurana, K.; Kollmann, P.; Krupp, N.; Louarn, P.; Roussos, E.; Sergis, N.

    2016-01-01

    Charged particle injections are regularly observed in Saturn's inner magnetosphere by Cassini. They are attributed to an ongoing process of flux-tube interchange driven by the strong centrifugal force associated with Saturn's rapid rotation. Numerical simulations suggest that these interchange injections can be associated with inward flow channels, in which plasma confined to a narrow range of longitudes moves radially toward the planet, gaining energy, while ambient plasma in the adjacent regions moves more slowly outward. Most previous analyses of these events have neglected this radial motion and inferred properties of the events under the assumption that they appear instantaneously at the spacecraft's L-shell and thereafter drift azimuthally. This paper describes features of injections that can be related to their radial motion prior to observation. We use a combination of phase space density profiles and an updated version of a test-particle model to quantify properties of the injection. We are able to infer the longitudinal width of the injection, the radial travel time from its point of origin, and the starting L shell of the injection. We can also predict which energies can remain inside the channel during the radial transport. To highlight the effects of radial propagation at a finite speed, we focus on those interchange injections without extensive features of azimuthal dispersion. Injections that have traveled radially for one or more hours prior to observation would have been initiated at a different local time than that of the observation. Finally, we describe an injection where particles have drifted azimuthally into a flow channel prior to observation by Cassini.

  7. An automated method for the simultaneous measurement of azole antifungal drugs in human plasma or serum using turbulent flow liquid chromatography-tandem mass spectrometry.

    PubMed

    Couchman, L; Buckner, S L; Morgan, P E; Ceesay, M M; Pagliuca, A; Flanagan, R J

    2012-08-01

    Azole antifungal drugs are important in the prophylaxis and treatment of invasive aspergillosis. Therapeutic drug monitoring may be indicated to (1) monitor adherence, (2) guide dosage and (3) minimise the risk of drug-drug interactions and dose-related toxicity. TurboFlow(TM) technology offers online, automated sample preparation. An Aria Transcend(TM) TLX-II coupled with a TSQ Vantage(TM) MS was used. Centrifuged samples (25 μL) were mixed with internal standard solution (975 μL) and 30 μL injected directly onto a C18-P-XL TurboFlow column. Analytes were focussed onto a Phenomenex Gemini Phenyl analytical column and eluted using a methanol/water gradient (flow-rate, 0.8 mL/min). Analytes were monitored in selected reaction monitoring mode (two transitions per analyte, positive mode APCI). Calibration ranges were as follows: itraconazole, hydroxyitraconazole, and posaconazole 0.05-5.0 mg/L; voriconazole and fluconazole 0.1-10 mg/L. Total analysis time was 12 min. TurboFlow column recovery was >77% for all analytes. Calibration was linear (R (2) > 0.99) for all analytes. Inter- and intra-assay imprecision (% RSD) was <8% and accuracy (nominal internal quality control values) 90-105% for all analytes. The limit of detection was 0.01 mg/L for all analytes. No matrix effects were observed. This method is simple, robust and suitable for measuring these compounds at concentrations attained during therapy. PMID:22695504

  8. A radio-high-performance liquid chromatography dual-flow cell gamma-detection system for on-line radiochemical purity and labeling efficiency determination.

    PubMed

    Lindegren, S; Jensen, H; Jacobsson, L

    2014-04-11

    In this study, a method of determining radiochemical yield and radiochemical purity using radio-HPLC detection employing a dual-flow-cell system is evaluated. The dual-flow cell, consisting of a reference cell and an analytical cell, was constructed from two PEEK capillary coils to fit into the well of a NaI(Tl) detector. The radio-HPLC flow was directed from the injector to the reference cell allowing on-line detection of the total injected sample activity prior to entering the HPLC column. The radioactivity eluted from the column was then detected in the analytical cell. In this way, the sample will act as its own standard, a feature enabling on-line quantification of the processed radioactivity passing through the system. All data were acquired on-line via an analog signal from a rate meter using chromatographic software. The radiochemical yield and recovery could be simply and accurately determined by integration of the peak areas in the chromatogram obtained from the reference and analytical cells using an experimentally determined volume factor to correct for the effect of different cell volumes. PMID:24630054

  9. Sharp Dissection versus Electrocautery for Radial Artery Harvesting

    PubMed Central

    Marzban, Mehrab; Arya, Reza; Mandegar, Mohammad Hossein; Karimi, Abbas Ali; Abbasi, Kiomars; Movahed, Namvar; Abbasi, Seyed Hesameddin

    2006-01-01

    Radial arteries have been increasingly used during the last decade as conduits for coronary artery revascularization. Although various harvesting techniques have been described, there has been little comparative study of arterial damage and patency. A radial artery graft was used in 44 consecutive patients, who were randomly divided into 2 groups. In the 1st group, the radial artery was harvested by sharp dissection and in the 2nd, by electrocautery. These groups were compared with regard to radial artery free flow, harvest time, number of clips used, complications, and endothelial damage. Radial artery free flow before and after intraluminal administration of papaverine was significantly greater in the electrocautery group (84.3 50.7 mL/min and 109.7 68.5 mL/min) than in the sharp-dissection group (52.9 18.3 mL/min and 69.6 28.2 mL/ min) (P =0.003). Harvesting time by electrocautery was significantly shorter (25.4 4.3 min vs 34.4 5.9 min) (P =0.0001). Electrocautery consumed an average of 9.76 clips, versus 22.45 clips consumed by sharp dissection. The 2 groups were not different regarding postoperative complications, except for 3 cases of temporary paresthesia of the thumb in the electrocautery group; histopathologic examination found no endothelial damage. We conclude that radial artery harvesting by electrocautery is faster and more economical than harvesting by sharp dissection and is associated with better intraoperative flow and good preservation of endothelial integrity. PMID:16572861

  10. Parachute drag and radial force

    SciTech Connect

    Purvis, J.W.

    1986-01-01

    This paper presents a combination of old and new wind tunnel data in a format which illustrates the effects of inflated diameter, geometric porosity, reefing line length, suspension line length, number of gores, and number of ribbons on parachute drag. A new definition of radial force coefficient is presented, as well as a universal drag curve for flat circular and conical parachutes.

  11. Simultaneous detection of multi-allergens in an incurred food matrix using ELISA, multiplex flow cytometry and liquid chromatography mass spectrometry (LC-MS).

    PubMed

    Gomaa, Ahmed; Boye, Joyce

    2015-05-15

    Food allergy is a public health concern and an important food safety issue. Food allergies affect up to 6% of infants and children and 4% of adults. The objective of this work was to determine differences in the detection of single and multiple allergens (i.e., casein, soy protein, and gluten) in an incurred food matrix before and after baking. Cookies were used as a model food system. Three methods, namely, multiplex assay (a new optimized method based on flow cytometry for multiple allergen analysis), enzyme-linked immunosorbent assay (ELISA) using commercial kits and LC-MS were used to detect allergens in the samples before and after baking. The ELISA kits performed well in detecting allergens in the raw samples with recoveries of 91-108%, 88-127% and 85-108% for casein, soy protein and gluten, respectively. Recoveries were poor for the baked cookies (67-90%, 66-95% and 66-88% for casein, soy protein and gluten, respectively). The multiplex flow cytometry assay permitted multiple allergen detection in the raw samples, with the following recoveries based on soluble protein: casein, 95-107%; soy protein, 92-97%, and gluten, 96-99%. Data for the baked cookies were as follows: casein, 84-90%; soy protein, 80-88%, and gluten, 80-90%. The LC-MS technique detected marker peptides that could be used to identify allergens in the baked food samples up to concentrations of 10 ppm for casein and soy protein, and 100 ppm for gluten. To the best of our knowledge, the current study is the first to compare ELISA, LC-MS and multiplex flow cytometry methods for the detection of multiple allergens simultaneously incurred in a model food system. PMID:25577123

  12. Simultaneous Quantification of ?9-Tetrahydrocannabinol, 11-nor-9-carboxy-Tetrahydrocannabinol, Cannabidiol and Cannabinol in Oral Fluid by MicroFlow-Liquid Chromatography-High Resolution Mass Spectrometry

    PubMed Central

    Concheiro, Marta; Lee, Dayong; Lendoiro, Elena; Huestis, Marilyn A.

    2014-01-01

    ?9-tetrahydrocannabinol (THC) is the primary target in oral fluid (OF) for detecting cannabis intake. However, additional biomarkers are needed to solve interpretation issues, such as the possibility of passive inhalation by identifying 11-nor-9-carboxy-THC (THCCOOH), and determining recent cannabis smoking by identifying cannabidiol (CBD) and/or cannabinol (CBN). We developed and comprehensively validated a microflow liquid chromatography (LC)high resolution mass spectrometry method for simultaneous quantification of THC, THCCOOH, CBD and CBN in OF collected with the Oral-Eze and Quantisal devices. One mL OF-buffer solution (0.25mL OF and 0.5mL of Oral-Eze buffer,1:3 dilution, or 0.75mL Quantisal buffer, 1:4 dilution) had proteins precipitated, and the supernatant subjected to CEREX Polycrom THC solid-phase extraction (SPE). Microflow LC reverse-phase separation was achieved with a gradient mobile phase of 10mM ammonium acetate pH 6 and acetonitrile over 10 min. We employed a Q Exactive high resolution mass spectrometer, with compounds identified and quantified by targeted-MSMS experiments. The assay was linear 0.550 ng/mL for THC, CBD and CBN, and 15500 pg/mL for THCCOOH. Intra- and inter-day and total imprecision were <10.8%CV and bias 86.5104.9%. Extraction efficiency was 52.4109.2%, process efficiency 12.2 88.9% and matrix effect ranged from ?86 to ?6.9%. All analytes were stable for 24h at 5C on the autosampler. The method was applied to authentic OF specimens collected with Quantisal and Oral-Eze devices. This method provides a rapid simultaneous quantification of THCCOOH and THC, CBD, CBN, with good selectivity and sensitivity, providing the opportunity to improve interpretation of cannabinoid OF results by eliminating the possibility of passive inhalation and providing markers of recent cannabis smoking. PMID:23726246

  13. Radial spreading of viscous-gravity currents with solidifying crust

    NASA Technical Reports Server (NTRS)

    Fink, Jonathan H.; Griffiths, Ross W.

    1990-01-01

    In the present investigation of solidifying-crust effects on the dynamics and surface morphology of radial viscous-gravity currents, polyethylene glycol inflows into the base of a tank holding a cold sucrose solution are used as analogs. As the radial current advanced away from the inlet, its surface solidified and deformed through a combination of folding anf fracturing. When cooling was sufficiently rapid, solid crust formed and caused the spreading rate to increase; progressively colder experiments revealed a sequence of surface morphologies resembling features of cooling lava flows and lava lakes, including multiarmed rift structures with shear offsets and bulbous lobate forms resembling pillow lavas on the ocean floor.

  14. Optical Chromatography of Bacterial Spores

    NASA Astrophysics Data System (ADS)

    Sundbeck, Steven; Terray, Alex; Arnold, Jonathan; Leski, Tomasz; Hart, Sean

    2007-03-01

    The technique of optical chromatography uses a laser mildly focused against fluid flow in a microfluidic channel to trap microscopic particles. Particles in the channel near the focal point of the laser are drawn toward the beam axis and then accelerated via optical pressure against the fluid flow, reaching an equilibrium point when the optical and fluidic forces on the particle are balanced. This equilibrium point may occur at differing distances from the focal point for microscopic particles with differing properties, such as size, shape, morphology, and refractive index. Thus, identification and separation of particles may be achieved in the system. Optical chromatography may be used as a detection technique for biological particles of interest, either directly or as a means of concentrating and filtering a sample. Of particular interest would be reliable methods for detection of Bacillus anthracis, a common weaponized biological agent. In this work we present optical chromatography experiments on bacterial spores which may be environmentally present with B. anthracis spores and interfere with detection.

  15. Multisyringe flow injection system for solid-phase extraction coupled to liquid chromatography using monolithic column for screening of phenolic pollutants.

    PubMed

    Oliveira, Hugo M; Segundo, Marcela A; Lima, Jos L F C; Cerd, Victor

    2009-02-15

    In this work a fast, automatic solid-phase extraction procedure hyphenated to HPLC-UV is proposed for screening of priority phenolic pollutants in waters at ng mL(-1) levels. A flow through column, containing polystyrene-divinylbenzene sorbent, was incorporated to a multisyringe flow injection system (MSFIA), where the sample loading and analyte elution were carried out after computer control. The MSFIA system also directed the eluent to fill the injection loop of the chromatograph, coupling the sample preparation to its determination. High enrichment factors were attained for phenol and ten of its derivatives (mean value 176 for 50 mL of sample), with LOD values lower than 1 ng mL(-1) for the maximum volume of sample used (100mL). For all analytes, mean recoveries between 89 and 103% were obtained for different water matrices. Certified reference material and a contaminated soil (RTC-CRM 112) were also tested successfully. The determination frequency was 4-10h(-1), providing an automatic, fast and reliable tool for water quality and environmental monitoring. PMID:19084666

  16. Potential of the reversed-inject differential flow modulator for comprehensive two-dimensional gas chromatography in the quantitative profiling and fingerprinting of essential oils of different complexity.

    PubMed

    Cordero, Chiara; Rubiolo, Patrizia; Cobelli, Luigi; Stani, Gianluca; Miliazza, Armando; Giardina, Matthew; Firor, Roger; Bicchi, Carlo

    2015-10-23

    In this study, the first capillary flow technology reverse-inject differential flow modulator was implemented with different column configurations (lengths, diameters and stationary phase coupling) and detector combinations (mass spectrometry--MS and flame ionization detection--FID) to evaluate its potential in the quantitative profiling and fingerprinting of medium-to-highly complex essential oils. In particular, a parallel dual-secondary column dual-detection configuration that has shown to improve the information potential also with thermally modulated GC × GC platforms (MS identification reliability and accurate FID quantitation), was tested. Several system performance parameters (separation measure SGC × GC, modulation ratio MR, separation space used and peak symmetry) were evaluated by analyzing a mixture of volatiles of interest in the flavor and fragrance field. The systems demonstrating the best chromatographic performance were selected for quantitative profiling of lavender and mint essential oils and fingerprinting of vetiver essential oil. Experimental results demonstrate that careful tuning of column dimensions and system configurations yields improved: (a) selectivity; (b) operable carrier gas linear velocities at close-to-optimal values; (c) (2)D separation power by extending the modulation period and (d) handling of overloaded peaks without dramatic losses in resolution and quantitative accuracy. PMID:26387790

  17. Interface evolution during radial miscible viscous fingering

    NASA Astrophysics Data System (ADS)

    Chui, Jane Y. Y.; de Anna, Pietro; Juanes, Ruben

    2015-10-01

    We study experimentally the miscible radial displacement of a more viscous fluid by a less viscous one in a horizontal Hele-Shaw cell. For the range of tested injection rates and viscosity ratios we observe two regimes for the evolution of the fluid-fluid interface. At early times the interface length increases linearly with time, which is typical of the Saffman-Taylor instability for this radial configuration. However, as time increases, the interface growth slows down and scales as t1/2 , as one expects in a stable displacement, indicating that the overall flow instability has shut down. Surprisingly, the crossover time between these two regimes decreases with increasing injection rate. We propose a theoretical model that is consistent with our experimental results, explains the origin of this second regime, and predicts the scaling of the crossover time with injection rate and the mobility ratio. The key determinant of the observed scalings is the competition between advection and diffusion time scales at the displacement front, suggesting that our analysis can be applied to other interfacial-evolution problems such as the Rayleigh-Bnard-Darcy instability.

  18. Radial gas turbines for industrial applications

    SciTech Connect

    1996-01-01

    A new radial-type gas turbine for the industrial markets is now being introduced by OPRA B.V., of Henelo, the Netherlands. The OP-16 gas turbine is a simple, all radial machine with a power output range of 1400 to 1600 kW. The gas turbine combines a moderate pressure ratio with a high degree of flexibility to cover several different types of application. A completely new design, the OP-16 gas turbine includes high-efficiency rotor components, a novel ultra-low-emission combustor, provision for subsequent incorporation of recuperation, as well as other features. One the most important new design features of the machine is the patented ultra-low-emissions combustor. Variation in fuel flow is automatically matched by means of the valve, ensuring near constant fuel/air ratio at all power levels. The fuel/air ratio is homogeneous and (and liquid fuel is vaporized), helping to provide close control of combustion temperature and hence emissions at all ratings. Good applications for the gas turbine include combined heat and power, mobile power plants, direct heating where ultra-clean exhaust is required, marine auxiliary power, peak load power supply and other applications where the engine`s flexibility is useful.

  19. Reactive-infiltration instability in radial geometry

    NASA Astrophysics Data System (ADS)

    Grodzki, Piotr; Szymczak, Piotr

    2015-04-01

    A planar dissolution front propagating through a homogeneous porous matrix is unstable with respect to small variations in local permeability; regions of high permeability dissolve faster because of enhanced transport of reactants, which leads to increased rippling of the front. This phenomenon, usually referred to known as reactive-infiltration instability is an important mechanism for pattern development in geology, with a range of morphologies and scales, from cave systems running for hundreds of miles to laboratory acidization on the scale of centimeters. In general, this instability is characterized by two length scales: the diffusive length (D/v) and the reactant penetration length (v/r), where v is the Darcy velocity, D - the diffusion constant and r - the dissolution rate. If the latter scale is much smaller than the former one can adopt the so-called thin front limit, where the interface is treated as a discontinuity in porosity, with a completely dissolved phase on one side and an undissolved phase on the other. Linear stability analysis for this case has been carried out by Chadam et al. [1], and the corresponding dispersion relation shows that long wavelengths are unstable, whereas short wavelengths are stabilized by diffusion. In their derivation, Chadam et al. have considered a linear geometry with a uniform pressure gradient applied along one of the directions. However, in many cases (e.g. in the acidization techniques used in oil industry) the reactive fluids are injected through a well and thus the relevant geometry is radial rather than linear. Motivated by this, we have carried out the linear stability analysis of the reactive-infiltration problem in radial geometry, with the fluid injection at the centre of the system. We stay within the thin-front limit and derive the corresponding dispersion relation, which shows the stable regions for both the long-wavelength and short-wavelength modes, and the unstable region in between. Next, we study how the instability growth rate depends on the Peclet number (Pe) and permeability contrast between the undissolved and dissolved phase (Γ) and find the region in the (Pe,Γ) space when the system is absolutely stable. This behaviour is in contrast to the viscous fingering problem in radial geometry [2], where for a given flow rate the front always becomes eventually unstable, after reaching a certain critical radius R. [1] J. Chadam, D. Ho , E. Merino, P. Ortoleva, A. Sen, Reactive In ltration Instabilities, IMA J. Appl. Math. 36, 207-221 (1986) [2] L. Paterson, Radial fingering in a Hele Shaw cell, J. Fluid Mech. 113, 513-529 (1981)

  20. Effects of stream-associated fluctuations upon the radial variation of average solar wind parameters

    NASA Technical Reports Server (NTRS)

    Goldstein, B. E.; Jokipii, J. R.

    1977-01-01

    A numerical MHD model in both spherically symmetric time-dependent and corotating equatorial flow approximations is used to compute the effects of nonlinear fluctuations due to solar wind streams upon radial gradients of average solar wind parameters. Significant effects of correlations between fluctuations on the gradients of azimuthal magnetic field, radial velocity, density, and azimuthal velocity are found. It is found that nonlinear fluctuations are a significant effect in determining the radial gradients of the solar wind at distances as small as 0.2 AU; at distances greater than 1 AU, nonlinear fluctuations dominate the behavior of the radial gradients.

  1. Separation and quantification of 238U, 232Th and rare earths in monazite samples by ion chromatography coupled with on-line flow scintillation detector.

    PubMed

    Borai, E H; Mady, A S

    2002-10-01

    An alternative procedure has been described for efficient separation and quantitative determination of uranium (U), thorium (Th) and rare earth elements (REEs) in monazite mineral by high performance ion chromatographic system (IC). Different variables affecting the distribution coefficient, the retention and hence separation efficiency such as eluent flow rate and concentrations of HCI and ammonium sulfate (NH4)2SO4 containing the mobile phase were studied. The developed separation protocol of U, Th and REEs was optimized using an Ion Pac CS5 separation column followed by post-column derivatization reaction with Arsenaso III and UV-VIS spectrophotometric detection. Comparative evaluation of U, Th and REEs concentration in monazite mineral was demonstrated using two different on-line detection modes including flow through cell scintillation detector (FSD) and UV-VIS spectrophotometer. Response of the FSD was found to be linear over the full range of activities investigated (4-100 Bq). The lower limits of detection (LLD) for the investigated radionuclides were 3.0+0.1 Bq for 238U and 6.0 +/- 0.1 Bq for 232Th. The detection of 238U and 232Th by FSD shows good agreement with the corresponding determination by UV-VIS spectrophotometer. The content of ThO2 and U3O8 in monazite sample were found to be 4.7 +/- 0.1% and 0.42 +/- 0.04% using UV-VIS detector and 4.3 +/- 0.1% and 0.45 +/- 0.1% using FSD, respectively. PMID:12361323

  2. Severity grading in radial dysplasia.

    PubMed

    Vilkki, S K

    2014-11-01

    A functional scoring method to grade the usefulness and quality of the upper limbs in congenital radial dysplasia is presented. It is based on the author's examinations of 44 arms with congenital deficiency of the radius. The hand (H), wrist (W) and proximal parts (P) of the extremity are each scored from 0 to 10 points for severity. The scoring is expressed similarly to the TNM (tumour, nodes, metastasis) tumour classification, for example as H5W4P2. The maximum severity index is 30 points. A severity grade of mild is between 1 and 8 points, moderate between 9 and 16 points and severe 17 points and over. In the author's series, the grades were mild in eight, moderate in 21 and severe in 15 cases. The functional severity grading should allow better comparison of radially deficient limbs and the results of treatment between groups of patients. PMID:24401744

  3. Performance of the same column in supercritical fluid chromatography and in liquid chromatography.

    PubMed

    Lambert, Nndor; Felinger, Attila

    2015-08-28

    We have studied the chromatographic behavior of the homologous series of alkylbenzenes (ranging from octylbenzene to octadecylbenzene) on the same C18 reversed-phase column in supercritical fluid chromatography (SFC) and reversed phase liquid chromatography (RPLC) at various experimental conditions, such as different eluent compositions, flow-rates, and mobile phase densities. The first and the second moments of the peaks were used to estimate the overall mass-transfer processes in both chromatographic modes using the stochastic model of chromatography. The results confirm that in SFC - as the density of the mobile phase is influenced by the flow-rate - there is a broader variation of mass-transfer properties than in liquid chromatography. As expected, the optimum mobile phase velocity is higher in SFC, but there is no real difference in the minimum value of plate height, i.e. in the optimum efficiency. PMID:26212802

  4. Radial Stability in Stratified Stars

    NASA Astrophysics Data System (ADS)

    Pereira, Jonas P.; Rueda, Jorge A.

    2015-03-01

    We formulate within a generalized distributional approach the treatment of the stability against radial perturbations for both neutral and charged stratified stars in Newtonian and Einstein's gravity. We obtain from this approach the boundary conditions connecting any two phases within a star and underline its relevance for realistic models of compact stars with phase transitions, owing to the modification of the star's set of eigenmodes with respect to the continuous case.

  5. Radial Electromagnetic Press for IGNITOR

    NASA Astrophysics Data System (ADS)

    Cucchiaro, A.; Anzidei, L.; Capriccioli, A.; Celentano, G.; Crescenzi, C.; Gasparotto, M.; Guerrieri, A.; Pizzuto, A.; Palmieri, A.; Rita, C.; Roccella, M.; Coppi, B.

    1998-11-01

    The structural performance of the IGNITOR machine relies upon a combination of both bucking between Toroidal Field Coils (TFCs), Central Solenoid (CS) and the Central Post (CP), and wedging in a well-defined area of the TFCs and of the magnet mechanical structure (called C-Clamps). This requires a pre-loading system to enhance the load bearing capability. Several solutions have been assessed and compared with each other within the operational scenarios and eventually a radial electromagnetic press has been selected as reference(Pizzuto A. et al., ENEA Report IGN/MAC/001/96). The loading system is made up by active coils and passive restraining rings. The radial active press consists of two pairs of coils (200x200mm each), symmetrically located relative to the machine equatorial plane and seating onto the passive rings. The permanent pre--load of the rings is applied through a wedging system with a load of about 120 MN. A radial electromagnetic press has the purpose of modulating the axial pressure on the TFC inner legs during the pulse. Design aspects including stress analysis, manufacturing, assembly and operational scenarios of the selected solution are presented in this paper.

  6. Automated and sensitive determination of four anabolic androgenic steroids in urine by online turbulent flow solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry: a novel approach for clinical monitoring and doping control.

    PubMed

    Guo, Feng; Shao, Jing; Liu, Qian; Shi, Jian-Bo; Jiang, Gui-Bin

    2014-07-01

    A novel method for automated and sensitive analysis of testosterone, androstenedione, methyltestosterone and methenolone in urine samples by online turbulent flow solid-phase extraction coupled with high performance liquid chromatography-tandem mass spectrometry was developed. The optimization and validation of the method were discussed in detail. The Turboflow C18-P SPE column showed the best extraction efficiency for all the analytes. Nanogram per liter (ng/L) level of AAS could be determined directly and the limits of quantification (LOQs) were 0.01 ng/mL, which were much lower than normally concerned concentrations for these typical anabolic androgenic steroids (AAS) (0.1 ng/mL). The linearity range was from the LOQ to 100 ng/mL for each compound, with the coefficients of determination (r(2)) ranging from 0.9990 to 0.9999. The intraday and interday relative standard deviations (RSDs) ranged from 1.1% to 14.5% (n=5). The proposed method was successfully applied to the analysis of urine samples collected from 24 male athletes and 15 patients of prostate cancer. The proposed method provides an alternative practical way to rapidly determine AAS in urine samples, especially for clinical monitoring and doping control. PMID:24840468

  7. Evaluation of interactions between metal ions and nonionic surfactants in high-concentration HCl using low-pressure high-performance liquid chromatography with low-flow-resistance polystyrene-based monolithic column.

    PubMed

    Hirano, Tomohiko; Kitagawa, Shinya; Ohtani, Hajime; Kinoshita, Takehiko; Ishigaki, Yuzo; Shibata, Nobuyuki; Nii, Susumu

    2013-10-01

    A method for evaluating the interactions between metal ions and nonionic surfactants in aqueous solutions containing high-concentration HCl, using gas pressure-driven low-pressure high-performance liquid chromatography (LP-HPLC) as a highly acid-resistant HPLC system, was developed. To construct the LP-HPLC for this purpose, poly(styrene-co-divinylbenzene)-based low-flow-resistance monolithic columns tolerant to highly acidic conditions were prepared using low-conversion thermal polymerization. Thermal polymerization at 65 °C for 1.5 h (monomer conversions, 33% for styrene and 59% for divinylbenzene) allowed preparation of a column with both high separation efficiency (around 60,000 plates m(-1) for alkylbenzenes) and a quite low back pressure of 0.14 MPa at a linear flow rate of 1 mm s(-1) (2.8 × 10(-13) m(2) in permeability). The base column prepared under the above conditions was coated with a nonionic surfactant, polyoxyethylene nonylphenyl ether (PONPE, average oxyethylene unit numbers (n) = 3, 7.5, 15, and 20), and used for evaluation of the interactions between PONPEs and metal ions in 6 M HCl. The interactions between PONPEs and Au(III), Ga(III), Fe(III), Zn(II), and Cu(II) were successfully evaluated using both breakthrough and chromatographic methods. Furthermore, a study of the effect of the polyoxyethylene (POE) chain length revealed that the use of PONPE with the longer POE moiety enhanced the magnitude of the interaction together with the increase in the amount of oxyethylene (OE) units coated on the monolith. Moreover, the interactions of metal ions with a single OE unit were almost constant in the range of n = 7.5-20, whereas the suppression of the interaction between Au(III) with the shortest PONPE chain (n = 3) was also observed. PMID:23884474

  8. Chromatography resin support

    DOEpatents

    Dobos, James G.

    2002-01-01

    An apparatus and method of using an improved chromatography resin support is disclosed. The chromatography support platform is provided by a stainless steel hollow cylinder adapted for being inserted into a chromatography column. An exterior wall of the stainless steel cylinder defines a groove for carrying therein an "O"-ring. The upper surface of the stainless steel column is covered by a fine stainless steel mesh welded to the edges of the stainless steel cylinder. When placed upon a receiving ledge defined within a chromatography column, the "O"-ring provides a fluid tight seal with the inner edge wall of the chromatography cylinder. The stainless steel mesh supports the chromatography matrix and provides a back flushable support which is economical and simple to construct.

  9. Tachoastrometry: astrometry with radial velocities

    NASA Astrophysics Data System (ADS)

    Pasquini, L.; Cortés, C.; Lombardi, M.; Monaco, L.; Leão, I. C.; Delabre, B.

    2015-02-01

    Context. Spectra of composite systems (e.g., spectroscopic binaries) contain spatial information that can be retrieved by measuring the radial velocities (i.e., Doppler shifts) of the components in four observations with the slit rotated by 90 degrees in the sky. Aims: We aim at developing a framework to describe the method and to test its capabilities in a real case. Methods: By using basic concepts of slit spectroscopy we show that the geometry of composite systems can be reliably retrieved by measuring only radial velocity differences taken with different slit angles. The spatial resolution is determined by the precision with which differential radial velocities can be measured. Results: We use the UVES spectrograph at the VLT to observe the known spectroscopic binary star HD 188088 (HIP 97944), which has a maximum expected separation of 23 milli-arcseconds. We measure an astrometric signal in radial velocity of 276 m s-1 , which corresponds to a separation between the two components at the time of the observations of 18 ± 2 milli-arcseconds. The stars were aligned east-west. We describe a simple optical device to simultaneously record pairs of spectra rotated by 180 degrees, thus reducing systematic effects. We compute and provide the function expressing the shift of the centroid of a seeing-limited image in the presence of a narrow slit. Conclusions: The proposed technique is simple to use and our test shows that it is amenable for deriving astrometry with milli-arcsecond accuracy or better, beyond the diffraction limit of the telescope. The technique can be further improved by using simple devices to simultaneously record the spectra with 180 degrees angles. This device together with an optimized data analysis will further reduce the measurement errors. With tachoastrometry, radial velocities and astrometric positions can be measured simultaneously for many double line system binaries in an easy way. The method is not limited to binary stars, but can be applied to any astrophysical configuration in which spectral lines are generated by separate (non-rotational symmetric) regions.

  10. Calculation of heat transfer in a radially rotating coolant passage

    SciTech Connect

    Tolpadi, A.K. )

    1994-12-01

    The three-dimensional flow field and heat transfer in a radially rotating coolant passage are studied numerically. The passage chosen has a square cross section with smooth isothermal walls of finite length. The axis rotation is normal to the flow direction with the flow radially outward. The effects of Coriolis forces, centrifugal buoyancy, and fluid Reynolds number on the flow and heat transfer have all been considered. The analysis has been performed by using a fully elliptic, three-dimensional, body-fitted computational fluid dynamics code based on pressure correction techniques. The numerical technique employs a multigrid iterative solution procedure and the standard k [minus] [epsilon] turbulence model for both the hydrodynamics and heat transfer. The effect of rotation is included by considering the governing equations of motion in a relative frame of reference that moves with the passage. The consequence of rotation is to bring higher velocity fluid from the core to the trailing surface, thereby increasing both the friction and heat transfer at this face. At the same time, the heat transfer is predicted to decrease along the leading surface. The effect of buoyancy is to increase the radial velocity of the fluid, thus generally increasing the heat transfer along both the leading and trailing surfaces. These effects and trends that have been predicted are in agreement with experimental heat transfer data available in the literature. The quantitative agreement with the data was also found to be quite satisfactory.

  11. A model of a radially expanding and contracting lymphangion.

    PubMed

    Rahbar, Elaheh; Moore, James E

    2011-04-01

    The lymphatic system is an extensive vascular network featuring valves and contractile walls that pump interstitial fluid and plasma proteins back to the main circulation. Immune function also relies on the lymphatic system's ability to transport white blood cells. Failure to drain and pump this excess fluid results in edema characterized by fluid retention and swelling of limbs. It is, therefore, important to understand the mechanisms of fluid transport and pumping of lymphatic vessels. Unfortunately, there are very few studies in this area, most of which assume Poiseuille flow conditions. In vivo observations reveal that these vessels contract strongly, with diameter changes of the order of magnitude of the diameter itself over a cycle that lasts typically 2-3s. The radial velocity of the contracting vessel is on the order of the axial fluid velocity, suggesting that modeling flow in these vessels with a Poiseuille model is inappropriate. In this paper, we describe a model of a radially expanding and contracting lymphatic vessel and investigate the validity of assuming Poiseuille flow to estimate wall shear stress, which is presumably important for lymphatic endothelial cell mechanotransduction. Three different wall motions, periodic sinusoidal, skewed sinusoidal and physiologic wall motions, were investigated with steady and unsteady parabolic inlet velocities. Despite high radial velocities resulting from the wall motion, wall shear stress values were within 4% of quasi-static Poiseuille values. Therefore, Poiseuille flow is valid for the estimation of wall shear stress for the majority of the lymphangion contractile cycle. PMID:21377158

  12. Fun with Paper Chromatography.

    ERIC Educational Resources Information Center

    Coleman, Dava; Hounshell, Paul B.

    1982-01-01

    Discusses paper chromatographic techniques and provides examples of typical classroom activities. Includes description of retardation values obtained during chromatography exercises and suggests using them for math lessons. (JN)

  13. Ion chromatography applications

    SciTech Connect

    Smith, R.E.

    1988-01-01

    This book describes recent advances in ion chromatography and demonstrates how it is used to solve scientific and industrial problems. The basic principles of ion chromatography are explained, including gradient elution of ions and micromembrane suppressors. The various anion and cation exchange columns together with various detection methods and applications of ion chromatography in the environmental and life sciences and industry are reviewed. Over 100 chromatograms which illustrate parameters needed to perform analysis and data on gradient and mobile phase ion chromatography are included.

  14. RADIAL STELLAR PULSATION AND THREE-DIMENSIONAL CONVECTION. II. TWO-DIMENSIONAL CONVECTION IN FULL AMPLITUDE RADIAL PULSATION

    SciTech Connect

    Geroux, Chris M.; Deupree, Robert G.

    2013-07-10

    We have developed a three-dimensional radiation hydrodynamics code to simulate the interaction of convection and radial pulsation in classical variable stars. One key goal is the ability to carry these simulations to full amplitude in order to compare them with observed light curves. Previous multi-dimensional calculations were prevented from reaching full amplitude because of drift in the radial coordinate system, due to the algorithm defining radial movement of the coordinate system during the pulsation cycle. We have removed this difficulty by defining our radial coordinate flow algorithm to require that the mass in a spherical shell remain constant for every time step throughout the pulsation cycle. We have used our new code to perform two-dimensional (2D) simulations of the interaction of radial pulsation and convection. We have made comparisons between light curves from our 2D convective simulations with observed light curves and find that our 2D simulated light curves are better able to match the observed light curve shape near the red edge of the RR Lyrae instability strip than light curves from previous one-dimensional time-dependent convective models.

  15. Confirmation of radial velocity variability in Arcturus

    NASA Technical Reports Server (NTRS)

    Cochran, William D.

    1988-01-01

    The paper presents results of high-precision measurements of radial-velocity variations in Alpha Boo. Significant radial-velocity variability is detected well in excess of the random and systematic measurement errors. The radial velocity varies by an amount greater than 200 m/sec with a period of around 2 days.

  16. Axial and Radial Oxylipin Transport.

    PubMed

    Gasperini, Debora; Chauvin, Adeline; Acosta, Ivan F; Kurenda, Andrzej; Stolz, Stphanie; Chtelat, Aurore; Wolfender, Jean-Luc; Farmer, Edward E

    2015-11-01

    Jasmonates are oxygenated lipids (oxylipins) that control defense gene expression in response to cell damage in plants. How mobile are these potent mediators within tissues? Exploiting a series of 13-lipoxygenase (13-lox) mutants in Arabidopsis (Arabidopsis thaliana) that displays impaired jasmonic acid (JA) synthesis in specific cell types and using JA-inducible reporters, we mapped the extent of the transport of endogenous jasmonates across the plant vegetative growth phase. In seedlings, we found that jasmonate (or JA precursors) could translocate axially from wounded shoots to unwounded roots in a LOX2-dependent manner. Grafting experiments with the wild type and JA-deficient mutants confirmed shoot-to-root oxylipin transport. Next, we used rosettes to investigate radial cell-to-cell transport of jasmonates. After finding that the LOX6 protein localized to xylem contact cells was not wound inducible, we used the lox234 triple mutant to genetically isolate LOX6 as the only JA precursor-producing LOX in the plant. When a leaf of this mutant was wounded, the JA reporter gene was expressed in distal leaves. Leaf sectioning showed that JA reporter expression extended from contact cells throughout the vascular bundle and into extravascular cells, revealing a radial movement of jasmonates. Our results add a crucial element to a growing picture of how the distal wound response is regulated in rosettes, showing that both axial (shoot-to-root) and radial (cell-to-cell) transport of oxylipins plays a major role in the wound response. The strategies developed herein provide unique tools with which to identify intercellular jasmonate transport routes. PMID:26338953

  17. Nonstandard jump functions for radially symmetric shock waves

    SciTech Connect

    Baty, Roy S.; Tucker, Don H.; Stanescu, Dan

    2008-10-01

    Nonstandard analysis is applied to derive generalized jump functions for radially symmetric, one-dimensional, magnetogasdynamic shock waves. It is assumed that the shock wave jumps occur on infinitesimal intervals, and the jump functions for the physical parameters occur smoothly across these intervals. Locally integrable predistributions of the Heaviside function are used to model the flow variables across a shock wave. The equations of motion expressed in nonconservative form are then applied to derive unambiguous relationships between the jump functions for the physical parameters for two families of self-similar flows. It is shown that the microstructures for these families of radially symmetric, magnetogasdynamic shock waves coincide in a nonstandard sense for a specified density jump function

  18. PRECISION RADIAL VELOCITIES WITH CSHELL

    SciTech Connect

    Crockett, Christopher J.; Prato, L.; Mahmud, Naved I.; Johns-Krull, Christopher M.; Jaffe, Daniel T.; Beichman, Charles A. E-mail: lprato@lowell.edu E-mail: cmj@rice.edu

    2011-07-10

    Radial velocity (RV) identification of extrasolar planets has historically been dominated by optical surveys. Interest in expanding exoplanet searches to M dwarfs and young stars, however, has motivated a push to improve the precision of near-infrared RV techniques. We present our methodology for achieving 58 m s{sup -1} precision in the K band on the M0 dwarf GJ 281 using the CSHELL spectrograph at the 3 m NASA Infrared Telescope Facility. We also demonstrate our ability to recover the known 4 M{sub JUP} exoplanet Gl 86 b and discuss the implications for success in detecting planets around 1-3 Myr old T Tauri stars.

  19. Fluctuating Pressure Environments and Hydrodynamic Radial Force Mitigation for a Two Blade Unshrouded Inducer

    NASA Technical Reports Server (NTRS)

    Mulder, Andrew; Skelley, Stephen

    2011-01-01

    Fluctuating pressure data from water flow testing of an unshrouded two blade inducer revealed a cavitation induced oscillation with the potential to induce a radial load on the turbopump shaft in addition to other more traditionally analyzed radial loads. Subsequent water flow testing of the inducer with a rotating force measurement system confirmed that the cavitation induced oscillation did impart a radial load to the inducer. After quantifying the load in a baseline configuration, two inducer shroud treatments were selected and tested to reduce the cavitation induced load. The first treatment was to increase the tip clearance, and the second was to introduce a circumferential groove near the inducer leading edge. Increasing the clearance resulted in a small decrease in radial load along with some steady performance degradation. The groove greatly reduced the hydrodynamic load with little to no steady performance loss. The groove did however generate some new, relatively high frequency, spatially complex oscillations to the flow environment.

  20. Liquid Chromatography in 1982.

    ERIC Educational Resources Information Center

    Freeman, David H.

    1982-01-01

    Reviews trends in liquid chromatography including apparatus, factors affecting efficient separation of a mixture (peak sharpness and speed), simplified problem-solving, adsorption, bonded phase chromatography, ion selectivity, and size exclusion. The current trend is to control chemical selectivity by the liquid phase. (Author/JN)

  1. Advanced proteomic liquid chromatography

    SciTech Connect

    Xie, Fang; Smith, Richard D.; Shen, Yufeng

    2012-10-26

    Liquid chromatography coupled with mass spectrometry is the predominant platform used to analyze proteomics samples consisting of large numbers of proteins and their proteolytic products (e.g., truncated polypeptides) and spanning a wide range of relative concentrations. This review provides an overview of advanced capillary liquid chromatography techniques and methodologies that greatly improve separation resolving power and proteomics analysis coverage, sensitivity, and throughput.

  2. Kool-Aid Chromatography

    ERIC Educational Resources Information Center

    Jenkins, Christie L.

    1986-01-01

    Offers guidelines and suggests activities that can introduce middle school students to the process and principles of chromatography in an inexpensive and safe manner. Proposes that experiences with Kool-aid and food coloring chromatography can provide insights into how scientists think, work, and communicate. (ML)

  3. Column Liquid Chromatography.

    ERIC Educational Resources Information Center

    Majors, Ronald E.; And Others

    1984-01-01

    Reviews literature covering developments of column liquid chromatography during 1982-83. Areas considered include: books and reviews; general theory; columns; instrumentation; detectors; automation and data handling; multidimensional chromatographic and column switching techniques; liquid-solid chromatography; normal bonded-phase, reversed-phase,

  4. High-performance liquid chromatography of chromatin histones.

    PubMed

    Gurley, L R; Prentice, D A; Valdez, J G; Spall, W D

    1983-08-26

    A method is described for the rapid analysis of histones by high-performance liquid chromatography on reversed-phase muBondapak columns, containing either octadecylsilane (C18) or cyanopropylsilane (CN) bonded to silica particles packed in either steel columns or Radial-Pak cartridges. A linear gradient progressing from water-acetonitrile (80:20) to water-acetonitrile (40:60) and increasing in acetonitrile concentration at the rate of 10%/h was used to elute the histones at a flow-rate of 1 ml/min for steel columns or 2 ml/min for Radial-Pak cartridges. Two conditions were found to be necessary to achieve histone fractionation: (1) silylation of the active silanol groups on the silica matrix, and (2) 0.1-0.3% trifluoroacetic acid in the eluting solvent. More than 95% of the total [3H]lysine-labeled protein applied to the CN column was eluted. The histone fractions were identified by their electrophoretic mobilities in both acid-urea and Triton DF-16 polyacrylamide gels. Histones were eluted from the columns in the following order: H1, H2B, (LHP)H2A, (MHP)H2A, H4, (LHP)H3, and (MHP)H3 (where LHP and MHP refer to the less-hydrophobic and more-hydrophobic histone variants). Phosphorylated and acetylated histone molecules were not separated from their unmodified parent molecules. The volatile nature of the water-acetonitrile-trifluoroacetic acid eluting solvent facilitated recovery of salt-free histones from the fractions by direct lyophilization of the column effluents. The best resolution of histone fractions was obtained with the Radial-Pak muBondapak C18 cartridge using 0.3% TFA. However, for analytical studies, the best detection was obtained by using the muBondapak CN steel column. Poorer resolution was obtained by using the non-silica based PRP-1 reversed-phase column, containing a polystyrene-divinylbenzene resin under the same conditions. PMID:6685132

  5. Radial-Electric-Field Piezoelectric Diaphragm Pumps

    NASA Technical Reports Server (NTRS)

    Bryant, Robert G.; Working, Dennis C.; Mossi, Karla; Castro, Nicholas D.; Mane, Pooma

    2009-01-01

    In a recently invented class of piezoelectric diaphragm pumps, the electrode patterns on the piezoelectric diaphragms are configured so that the electric fields in the diaphragms have symmetrical radial (along-the-surface) components in addition to through-the-thickness components. Previously, it was accepted in the piezoelectric-transducer art that in order to produce the out-of-plane bending displacement of a diaphragm needed for pumping, one must make the electric field asymmetrical through the thickness, typically by means of electrodes placed on only one side of the piezoelectric material. In the present invention, electrodes are placed on both sides and patterned so as to produce substantial radial as well as through-the-thickness components. Moreover, unlike in the prior art, the electric field can be symmetrical through the thickness. Tests have shown in a given diaphragm that an electrode configuration according to this invention produces more displacement than does a conventional one-sided electrode pattern. The invention admits of numerous variations characterized by various degrees of complexity. Figure 1 is a simplified depiction of a basic version. As in other piezoelectric diaphragm pumps of similar basic design, the prime mover is a piezoelectric diaphragm. Application of a suitable voltage to the electrodes on the diaphragm causes it to undergo out-of-plane bending. The bending displacement pushes a fluid out of, or pulls the fluid into, a chamber bounded partly by the diaphragm. Also as in other diaphragm pumps in general, check valves ensure that the fluid flows only in through one port and only out through another port.

  6. Rapid determination of N-acetyl-4-aminophenol (paracetamol) in urine by tandem mass spectrometry coupled with on-line clean-up by two dimensional turbulent flow/reversed phase liquid chromatography.

    PubMed

    Modick, Hendrik; Schütze, André; Pälmke, Claudia; Weiss, Tobias; Brüning, Thomas; Koch, Holger M

    2013-04-15

    N-Acetyl-4-aminophenol (NAAP) is the major urinary metabolite of aniline. The general population is known to be ubiquitously exposed to aniline through various sources. Furthermore, NAAP, known under the trade name paracetamol (resp. acetaminophen), is one of the most commonly used over-the-counter analgesics. Recent studies suggest anti-androgenic properties of NAAP. Although NAAP has been used as a pain reliever over decades and its role in aniline metabolism is well known there is a lack of internal exposure data both in environmental and occupational settings. To determine the internal NAAP exposure of the general population, workers exposed to aniline and users of paracetamol we developed a fast on-line HPLC-MS/MS method with isotope dilution quantification of NAAP after enzymatic hydrolysis of its conjugates in urine. We achieved minimal sample pretreatment through on-line extraction and enrichment of the analyte by turbulent flow chromatography on a Waters Oasis HLB phase followed by back-flush transfer onto the analytical column. The limit of quantification (LOQ) was 0.75 μg/L. In a pilot study, urine samples of 21 volunteers, not occupationally exposed to aniline, were analyzed for NAAP. NAAP was detected in all samples in a wide concentration range between 8.7 μg/L and 22100 μg/L (median 85.7 μg/L). The highest concentration was measured in a volunteer who took paracetamol one day ago. Half of the volunteers quoted to either never have taken paracetamol or at least not during several weeks before the study. Therefore, other routes of exposure than direct use of paracetamol, like aniline or paracetamol contaminated foodstuff, leading to the NAAP excretions have to be taken into account. PMID:23518644

  7. Liquid-phase chromatography detector

    DOEpatents

    Voigtman, Edward G.; Winefordner, James D.; Jurgensen, Arthur R.

    1983-01-01

    A liquid-phase chromatography detector comprising a flow cell having an inlet tubular conduit for receiving a liquid chromatographic effluent and discharging it as a flowing columnar stream onto a vertically adjustable receiving surface spaced apart from and located vertically below and in close proximity to the discharge end of the tubular conduit; a receiver adapted to receive liquid overflowing from the receiving surface; an exit conduit for continuously removing liquid from the receiver; a light source for focussing fluorescence-producing light pulses on the flowing columnar stream as it passes from the outlet of the conduit to the receiving surface and a fluorescence detector to detect the produced fluorescence; a source of light pulse for producing acoustic waves in the columnar stream as it passes from the conduit outlet to the receiving surface; and a piezoelectric transducer adapted to detect those waves; and a source of bias voltage applied to the inlet tubular conduit and adapted to produce ionization of the liquid flowing through the flow cell so as to produce photocurrents therein and an electrical system to detect and record the photocurrents. This system is useful in separating and detecting individual chemical compounds from mixtures thereof.

  8. Liquid-phase chromatography detector

    DOEpatents

    Voigtman, E.G.; Winefordner, J.D.; Jurgensen, A.R.

    1983-11-08

    A liquid-phase chromatography detector comprises a flow cell having an inlet tubular conduit for receiving a liquid chromatographic effluent and discharging it as a flowing columnar stream onto a vertically adjustable receiving surface spaced apart from and located vertically below and in close proximity to the discharge end of the tubular conduit; a receiver adapted to receive liquid overflowing from the receiving surface; an exit conduit for continuously removing liquid from the receiver; a light source for focusing fluorescence-producing light pulses on the flowing columnar stream as it passes from the outlet of the conduit to the receiving surface and a fluorescence detector to detect the produced fluorescence; a source of light pulse for producing acoustic waves in the columnar stream as it passes from the conduit outlet to the receiving surface; and a piezoelectric transducer adapted to detect those waves; and a source of bias voltage applied to the inlet tubular conduit and adapted to produce ionization of the liquid flowing through the flow cell so as to produce photocurrents therein and an electrical system to detect and record the photocurrents. This system is useful in separating and detecting individual chemical compounds from mixtures thereof. 5 figs.

  9. Sample concentration using optical chromatography

    NASA Astrophysics Data System (ADS)

    Hart, Sean J.; Terray, Alex; Arnold, Jonathan; Leski, Tomasz A.

    2007-03-01

    Optical chromatography is a technique for the separation of particles that capitalizes on the balance between optic and fluidic forces. When microscopic particles in a fluid flow encounter a laser beam propagating in the opposite direction, they are trapped axially along the beam. They are then optically pushed upstream from the laser focal point to rest at a point where the optic and fluidic forces on the particle balance. Because optical and fluid forces are sensitive to differences in the physical and chemical properties of a particle, both coarse and fine separations are possible. We describe how an optical chromatography beam directed into a tailored flow environment, has been adapted to operate as an optical filter for the concentration / bioenrichment of colloidal and biological samples. In this work, the demonstrated ability to concentrate spores of the biowarfare agent, Bacillus anthracis, may have significant impact in the biodefense arena. Application of these techniques and further design of fluidic and optical environments will allow for more specific identification, concentration and separation of many more microscopic particle and biological suspensions.

  10. Analyses of hydrodynamic radial forces on centrifugal pump impellers

    NASA Astrophysics Data System (ADS)

    Adkins, D. R.; Brennen, C. E.

    1988-03-01

    An experimental and theoretical study of the hydrodynamic interactions occurring between a centrifugal pump impeller and a volute is presented. The theoretical analysis provides a quasi-one-dimensional treatment of the flow in the volute, and it is extended to include the hydrodynamic force perturbations caused by the impeller whirling eccentrically in the volute. It is noted that these perturbations are often destabilizing. The theoretical models were found to accurately predict the radial forces caused by the flow through the impeller. The pressure acting on the front shroud of the impeller is shown to have a significant effect on the destabilizing hydrodyamic forces.

  11. Analyses of hydrodynamic radial forces on centrifugal pump impellers

    NASA Technical Reports Server (NTRS)

    Adkins, D. R.; Brennen, C. E.

    1988-01-01

    An experimental and theoretical study of the hydrodynamic interactions occurring between a centrifugal pump impeller and a volute is presented. The theoretical analysis provides a quasi-one-dimensional treatment of the flow in the volute, and it is extended to include the hydrodynamic force perturbations caused by the impeller whirling eccentrically in the volute. It is noted that these perturbations are often destabilizing. The theoretical models were found to accurately predict the radial forces caused by the flow through the impeller. The pressure acting on the front shroud of the impeller is shown to have a significant effect on the destabilizing hydrodyamic forces.

  12. An overview of sequential injection chromatography.

    PubMed

    Chocholous, Petr; Solich, Petr; Satínský, Dalibor

    2007-09-26

    New generation of sequential injection analysis (SIA) called sequential injection chromatography (SIC) has already been consolidated as a good alternative of high performance liquid chromatography (HPLC) for fast analysis of simple samples. Benefits of flow methods are automation, miniaturization and low sample and mobile phase consumption. Implementation of short monolithic chromatographic column into SIA opens new area-on-line chromatographic separation of multi-compound sample in low-pressure flow system, with the advantage of flow programming and possibility of sample manipulation. In the presented review the potential of SIC and its comparison with HPLC for determination of pharmaceutical mixtures is discussed and outlines past and recent trends focused on separation with SIC. PMID:17903474

  13. A fully relativistic radial fall

    NASA Astrophysics Data System (ADS)

    Spallicci, Alessandro D. A. M.; Ritter, Patxi

    2014-10-01

    Radial fall has historically played a momentous role. It is one of the most classical problems, the solutions of which represent the level of understanding of gravitation in a given epoch. A gedankenexperiment in a modern frame is given by a small body, like a compact star or a solar mass black hole, captured by a supermassive black hole. The mass of the small body itself and the emission of gravitational radiation cause the departure from the geodesic path due to the back-action, that is the self-force. For radial fall, as any other non-adiabatic motion, the instantaneous identity of the radiated energy and the loss of orbital energy cannot be imposed and provide the perturbed trajectory. In the first part of this paper, we present the effects due to the self-force computed on the geodesic trajectory in the background field. Compared to the latter trajectory, in the Regge-Wheeler, harmonic and all others smoothly related gauges, a far observer concludes that the self-force pushes inward (not outward) the falling body, with a strength proportional to the mass of the small body for a given large mass; further, the same observer notes a higher value of the maximal coordinate velocity, this value being reached earlier during infall. In the second part of this paper, we implement a self-consistent approach for which the trajectory is iteratively corrected by the self-force, this time computed on osculating geodesics. Finally, we compare the motion driven by the self-force without and with self-consistent orbital evolution. Subtle differences are noticeable, even if self-force effects have hardly the time to accumulate in such a short orbit.

  14. Radial and vertical mixing in protoplanetary accretion disks

    NASA Astrophysics Data System (ADS)

    Wehrstedt, Michael; Gail, H.-P.

    Crystalline silicates and aliphatic hydrocarbons in comets as well as deuterated species in several solar system bodies indicate an extensive radial mixing in the primodial solar nebula, i.e. the protoplanetary accretion disk of our solar system. To study the radial transport of matter within protoplanetary disks it is essential to resolve the vertical direction since matter is mixed radially outward by vertical `detour' in the complex flow of the disk. In this work we perform numerical models of protoplanetary accretion disks with radial and vertical mixing by solving a set of 2-dimensional diffusion-advection-reaction equations for different tracers self-consistently with the set of disk equations in the 1+1-dimensional approximation. Tracers are silicate grains (olivine, pyroxene) which anneal in the warm inner parts of the disk and carbonaceous grains which combust by surface reaction with OH molecules. Considerable fractions of crystallized silicates as well as methan as a product of carbon combustion are transported to the location of formation of comets afar from the protosun.

  15. Magnetically suspended centrifugal blood pump with a radial magnetic driver.

    PubMed

    Hoshi, Hideo; Katakoa, Kiroyuki; Ohuchi, Katsuhiro; Asama, Jun-ichi; Shinshi, Tadahiko; Shimokohbe, Akira; Takatani, Setsuo

    2005-01-01

    A new magnetic bearing has been designed to achieve a low electronic power requirement and high stiffness. The magnetic bearing consists of 1) radial passive forces between the permanent magnet ring mounted inside the impeller rotor and the electromagnet core materials in the pump casing and 2) radial active forces generated by the electromagnets using the two gap sensor signals. The magnetic bearing was assembled into a centrifugal rotary blood pump (CRBP) driven with a radial, magnetic coupled driver. The impeller vane shape was designed based upon the computational fluid dynamic simulation. The diameter and height of the CRBP were 75 mm and 50 mm, respectively. The magnetic bearing system required the power of 1.0-1.4 W. The radial impeller movement was controlled to within +/- 10 microm. High stiffness in the noncontrolled axes, Z, phi, and theta, was obtained by the passive magnetic forces. The pump flow of 5 L/min against 100 mm Hg head pressure was obtained at 1,800 rpm with the electrical to hydraulic efficiency being greater than 15%. The Normalized Index of Hemolysis (NIH) of the magnetic bearing CRBP was one fifth of the BioPump BP-80 and one half of the NIKKISO HPM-15 after 4 hours. The newly designed magnetic bearing with two degrees of freedom control in combination with optimized impeller vane was successful in achieving an excellent hemolytic performance in comparison with the clinical centrifugal blood pumps. PMID:15745136

  16. High performance stationary phases for planar chromatography.

    PubMed

    Poole, Salwa K; Poole, Colin F

    2011-05-13

    The kinetic performance of stabilized particle layers, particle membranes, and thin films for thin-layer chromatography is reviewed with a focus on how layer characteristics and experimental conditions affect the observed plate height. Forced flow and pressurized planar electrochromatography are identified as the best candidates to overcome the limited performance achieved by capillary flow for stabilized particle layers. For conventional and high performance plates band broadening is dominated by molecular diffusion at low mobile phase velocities typical of capillary flow systems and by mass transfer with a significant contribution from flow anisotropy at higher flow rates typical of forced flow systems. There are few possible changes to the structure of stabilized particle layers that would significantly improve their performance for capillary flow systems while for forced flow a number of avenues for further study are identified. New media for ultra thin-layer chromatography shows encouraging possibilities for miniaturized high performance systems but the realization of their true performance requires improvements in instrumentation for sample application and detection. PMID:21056422

  17. Numerical modeling of the elution peak profiles of retained solutes in supercritical fluid chromatography

    SciTech Connect

    Kaczmarski, Krzysztof; Guiochon, Georges A

    2011-01-01

    In supercritical fluid chromatography (SFC), the significant expansion of the mobile phase along the column causes the formation of axial and radial gradients of temperature. Due to these gradients, the mobile phase density, its viscosity, its velocity, its diffusion coefficients, etc. are not constant throughout the column. This results in a nonuniform flow velocity distribution, itself causing a loss of column efficiency in certain cases, even at low flow rates, as they do in HPLC. At high flow rates, an important deformation of the elution profiles of the sample components may occur. The model previously used to account satisfactorily for the retention of an unsorbed solute in SFC is applied to the modeling of the elution peak profiles of retained compounds. The numerical solution of the combined heat and mass balance equations provides the temperature and the pressure profiles inside the column and values of the retention time and the band profiles of retained compounds that are in excellent agreement with independent experimental data for large value of mobile phase reduced density. At low reduced densities, the band profiles can strongly depend on the column axial distribution of porosity.

  18. Hollow Cathode With Multiple Radial Orifices

    NASA Technical Reports Server (NTRS)

    Brophy, John R.

    1992-01-01

    Improved hollow cathode serving as source of electrons has multiple radial orifices instead of single axial orifice. Distributes ion current more smoothly, over larger area. Prototype of high-current cathodes for ion engines in spacecraft. On Earth, cathodes used in large-diameter ion sources for industrial processing of materials. Radial orientation of orifices in new design causes current to be dispersed radially in vicinity of cathode. Advantageous where desireable to produce plasma more nearly uniform over wider region around cathode.

  19. Special Report: Affinity Chromatography.

    ERIC Educational Resources Information Center

    Parikh, Indu; Cuatrecasas, Pedro

    1985-01-01

    Describes the nature of affinity chromatography and its use in purifying enzymes, studying cell interactions, exploring hormone receptors, and other areas. The potential the technique may have in treating disease is also considered. (JN)

  20. Advanced proteomic liquid chromatography

    PubMed Central

    Xie, Fang; Smith, Richard D.; Shen, Yufeng

    2012-01-01

    Liquid chromatography coupled with mass spectrometry is the predominant platform used to analyze proteomics samples consisting of large numbers of proteins and their proteolytic products (e.g., truncated polypeptides) and spanning a wide range of relative concentrations. This review provides an overview of advanced capillary liquid chromatography techniques and methodologies that greatly improve separation resolving power and proteomics analysis coverage, sensitivity, and throughput. PMID:22840822

  1. Gas chromatography in space

    NASA Technical Reports Server (NTRS)

    Akapo, S. O.; Dimandja, J. M.; Kojiro, D. R.; Valentin, J. R.; Carle, G. C.

    1999-01-01

    Gas chromatography has proven to be a very useful analytical technique for in situ analysis of extraterrestrial environments as demonstrated by its successful operation on spacecraft missions to Mars and Venus. The technique is also one of the six scientific instruments aboard the Huygens probe to explore Titan's atmosphere and surface. A review of gas chromatography in previous space missions and some recent developments in the current environment of fiscal constraints and payload size limitations are presented.

  2. Radial artery remodeling in response to shear stress increase within arteriovenous fistula for hemodialysis access.

    PubMed

    Ene-Iordache, Bogdan; Mosconi, Lidia; Antiga, Luca; Bruno, Simona; Anghileri, Abramo; Remuzzi, Giuseppe; Remuzzi, Andrea

    2003-01-01

    It is known that changes in blood flow induce vascular remodeling and that shear stress, the tractive force acting on the vessel wall due to blood flowing, influences endothelial cell function. The aim of the present study was to investigate the relation between changes in pulsatile shear forces and arterial remodeling in response to chronic elevation in blood flow within the radial artery. The authors studied vessel diameter, flow rate, and shear stress in the radial artery of uremic patients before and after surgical creation of a native arteriovenous fistula for hemodialysis access. For this purpose, the authors used echo-color-Doppler ultrasound to perform diameter and blood velocity measurements. Time-function blood flow rate and wall shear stress were calculated based on arterial diameter, center-line velocity wave-form, and blood viscosity, using a numerical method developed according to Womersley's theory for unsteady flow in tubes. The results confirmed that the radial artery diameter increases in response to a chronic increase in blood flow in uremic patients. Moreover, it seems that the radial artery dilates in such a way as to maintain the peak wall shear stress constant, suggesting that endothelial cells sense the maximum rather than the time-averaged wall shear stress. This finding may lead to further understanding of the mechanisms responsible for endothelial response to physical stimulation by flowing blood. PMID:12791517

  3. Hub and shroud fillets influence on the radial compressor stage efficiency

    NASA Astrophysics Data System (ADS)

    Syka, Tom; Matas, Richard; K?ourek, Jind?ich

    2015-05-01

    Article describes numerical simulations of an air flow in the radial compressor stage in the NUMECA CFD software. During the tasks evaluating the stepped and straight impeller seals and hub and shroud fillets influence on working characteristics and flow field was observed. Also the CFD results comparison with results from the empiric design tool and the measurement is described.

  4. Continuous time random walks for non-local radial solute transport

    NASA Astrophysics Data System (ADS)

    Dentz, Marco; Kang, Peter K.; Le Borgne, Tanguy

    2015-08-01

    This study formulates and analyzes continuous time random walk (CTRW) models in radial flow geometries for the quantification of non-local solute transport induced by heterogeneous flow distributions and by mobile-immobile mass transfer processes. To this end we derive a general CTRW framework in radial coordinates starting from the random walk equations for radial particle positions and times. The particle density, or solute concentration is governed by a non-local radial advection-dispersion equation (ADE). Unlike in CTRWs for uniform flow scenarios, particle transition times here depend on the radial particle position, which renders the CTRW non-stationary. As a consequence, the memory kernel characterizing the non-local ADE, is radially dependent. Based on this general formulation, we derive radial CTRW implementations that (i) emulate non-local radial transport due to heterogeneous advection, (ii) model multirate mass transfer (MRMT) between mobile and immobile continua, and (iii) quantify both heterogeneous advection in a mobile region and mass transfer between mobile and immobile regions. The expected solute breakthrough behavior is studied using numerical random walk particle tracking simulations. This behavior is analyzed by explicit analytical expressions for the asymptotic solute breakthrough curves. We observe clear power-law tails of the solute breakthrough for broad (power-law) distributions of particle transit times (heterogeneous advection) and particle trapping times (MRMT model). The combined model displays two distinct time regimes. An intermediate regime, in which the solute breakthrough is dominated by the particle transit times in the mobile zones, and a late time regime that is governed by the distribution of particle trapping times in immobile zones. These radial CTRW formulations allow for the identification of heterogeneous advection and mobile-immobile processes as drivers of anomalous transport, under conditions relevant for field tracer tests.

  5. Fabrication of cooled radial turbine rotor

    NASA Technical Reports Server (NTRS)

    Hammer, A. N.; Aigret, G. G.; Psichogios, T. P.; Rodgers, C.

    1986-01-01

    A design and fabrication program was conducted to evaluate a unique concept for constructing a cooled, high temperature radial turbine rotor. This concept, called split blade fabrication was developed as an alternative to internal ceramic coring. In this technique, the internal cooling cavity is created without flow dividers or any other detail by a solid (and therefore stronger) ceramic plate which can be more firmly anchored within the casting shell mold than can conventional detailed ceramic cores. Casting is conducted in the conventional manner, except that the finished product, instead of having finished internal cooling passages, is now a split blade. The internal details of the blade are created separately together with a carrier sheet. The inserts are superalloy. Both are produced by essentially the same software such that they are a net fit. The carrier assemblies are loaded into the split blade and the edges sealed by welding. The entire wheel is Hot Isostatic Pressed (HIPed), braze bonding the internal details to the inside of the blades. During this program, two wheels were successfully produced by the split blade fabrication technique.

  6. Effect of radial inflow on vortex intensification for a tornado-type wind turbine

    SciTech Connect

    Hsu, C.T.; Ide, H.

    1982-09-01

    A new wind vortex turbine, called tornado-type wind turbine, was studied both theoretically and experimentally for the purpose of better understanding the basic nature of a vortex flow and further improvement of its power efficiencies. Analytical solutions were obtained from the Navier-Stokes equations for the velocity distributions along the radial distance. The result demonstrates the important nature of a vortex structure that, in order to intensify a vortex inside the tower, radial inflow must be provided from the side walls. Based upon this concept, the essential contribution of our experimental work was to furnish the radial inflow by utilizing the dynamic head of incoming wind.

  7. Radial forces in a centrifugal compressor; Experimental investigation by using magnetic bearings and static pressure distribution

    NASA Astrophysics Data System (ADS)

    Reunanen, Arttu; Larjola, Jaakko

    2005-03-01

    The volute of a centrifugal compressor causes a non-uniform pressure distribution which leads to a radial force on the impeller. This force was measured using magnetic bearings. In addition, the radial force was estimated using the static pressure distribution measured at the impeller outlet. The impeller force was found to be the highest at choke, the lowest at the design flow and moderate at stall. The radial force determined from the pressure measurements was only slightly different from the force obtained from the bearing measurements. The rotational speed was seen to affect the force to some extent.

  8. Radial artery wall shear stress evaluation in patients with arteriovenous fistula for hemodialysis access.

    PubMed

    Remuzzi, Andrea; Ene-Iordache, Bogdan; Mosconi, Lidia; Bruno, Simona; Anghileri, Abramo; Antiga, Luca; Remuzzi, Giuseppe

    2003-01-01

    It has been extensively documented that changes in blood flow induce vascular remodeling and this phenomenon seems to be correlated to the shear forces imposed on the vessel wall by motion of blood. Wall shear stress, the tractive force that acts on the endothelium, has been shown to influence endothelial cell function. To study changes in wall shear stress that develop on the vessel wall upon changes of blood flow, we set up a technique that allows estimation of shear stress in the radial artery of patients on chronic hemodialysis therapy. The technique is based on color-flow Doppler examination of the radial artery before and after surgical creation of radiocephalic fistula for hemodialysis. Calculation of time function wall shear stress and blood flow rate in the radial artery is performed on the basis of arterial diameter, center-line velocity waveform and blood viscosity, using a numerical method developed according to Womersley's theory for pulsatile flow in tubes. The results presented confirm that the model developed is suitable for calculation of the wall shear stress that develops in the radial artery of patients before and after surgical creation of an arteriovenous fistula for hemodialysis. This methodology was developed for characterization of wall shear stress in the radial artery but may be well applied to other vessels that can be examined by echo-Doppler technique. PMID:12454436

  9. Experimental evaluation of a translating nozzle sidewall radial turbine

    NASA Technical Reports Server (NTRS)

    Roelke, Richard J.; Rogo, Casimir

    1987-01-01

    An experimental performance evaluation was made of two movable sidewall variable area radial turbines. The turbine designs were representative of the gas generator turbine of a variable flow capacity rotorcraft engine. The first turbine was an uncooled design while the second turbine had a cooled nozzle but an uncooled rotor. The cooled nozzle turbine was evaluated both with and without coolant flow. The test results showed that the movable nozzle wall is a viable and efficient means to effectively control the flow capacity of a radial turbine. Peak efficiencies of the second turbine with and without nozzle coolant were 86.5 and 88 percent respectively. These values are comparable to pivoting vane variable geometry turbines; however, the decrease in efficiency as the flow was varied from the design value was much less for the movable wall turbine. Several design improvements which should increase the turbine efficiency one or two more points are identified. These design improvements include reduced leakage losses and relocation of the vane coolant ejection holes to reduce mainstream disturbance.

  10. Radial spin Hall effect of light

    NASA Astrophysics Data System (ADS)

    Shu, Weixing; Ke, Yougang; Liu, Yachao; Ling, Xiaohui; Luo, Hailu; Yin, Xiaobo

    2016-01-01

    We propose and realize a radial spin Hall effect (SHE) of light by using a dielectric metasurface. The metasurface with radially varying optical axes introduces a Pancharatnam-Berry (PB) geometrical phase to the incident light. The spatial gradient of PB phase accounts for a shift in the momentum space and thus leads the light to split radially into two concentric rays with opposite spin in the position space, which is called a radial SHE. Further experiments verify that the magnitude of the splitting increases with the rotation rate of the optical-axis orientation and the propagation distance, thereby allowing for macroscopic observation of the SHE. We also find that the phase of the incident light influences the profiles of the two split rays, while the polarization determines their intensities. The results provide methods to tune the SHE of light by engineering metasurfaces and modulating the incident light, and this radial SHE may be extrapolated to other physical systems.

  11. Aerodynamic Evaluation of Two Compact Radial-Inflow Turbine Rotors

    NASA Technical Reports Server (NTRS)

    Simonyi, P. Susan; Roelke, Richard J.; Stabe, Roy G.; Nowlin, Brentley C.; Dicicco, Danielle

    1995-01-01

    The aerodynamic evaluation of two highly loaded compact radial turbine rotors was conducted at the NASA Lewis Research Center Small Engine Component Test Facility (SECTF). The experimental results were used for proof-of-concept, for modeling radial inflow turbine rotors, and for providing data for code verification. Two rotors were designed to have a shorter axial length, up to a 10-percent reduced diameter, a lighter weight, and equal or higher efficiencies with those of conventional radial inflow turbine rotors. Three configurations were tested: rotor 1, having a 40-percent shorter axial length, with the design stator (stator 1); rotor 1 with the design stator vanes closed down (stator 2); and rotor 2, slightly shorter axially and having higher loading, with stator 2. The stator had 36 vanes and the rotors each had 14 solid blades. Although presently uncooled, the rotor blades were designed for thicknesses which would allow cooling passages to be added. The overall stage performance measurements and the rotor and stator exit flow field surveys were obtained. Measurements of steady state temperatures, pressures, mass flow rates, flow angles, and output power were made at various operating conditions. Data were obtained at corrected speeds of 80, 90, 100, 110, and 120 percent of design over a range of equivalent inlet-to-exit pressure ratios of 3.5, 4.0, 4.5, and 5.0, the maximum pressure ratio achieved. The test showed that the configuration of rotor 1 with stator 1 running at the design pressure ratio produced a flow rate which was 5.6 percent higher than expected. This result indicated the need to close down the stator flow area to reduce the flow. The flow area reduction was accomplished by restaggering the vanes. Rotor 1 was retested with the closed-down stator vanes and achieved the correct mass flow. Rotor 2 was tested only with the restaggered vanes. The test results of the three turbine configurations were nearly identical. Although the measured efficiencies of the compact designs fell 2 to 3 points below the predicted efficiency of 91 percent, they did meet and exceed by up to 2.5 percentage points the efficiences of state-of-the-art turbines found in the literature.

  12. Eddy Current Minimizing Flow Plug for Use in Flow Conditioning and Flow Metering

    NASA Technical Reports Server (NTRS)

    England, John Dwight (Inventor); Kelley, Anthony R. (Inventor)

    2015-01-01

    An eddy-current-minimizing flow plug has an outer radial wall with open flow channels formed between the plug's inlet and outlet. The plug has a central region coupled to the inner surface of the outer radial wall. Each open flow channel includes (i) a first portion originating at the inlet and converging to a location in the plug where convergence is contributed to by changes in thickness of the outer radial wall and divergence of the central region, and (ii) a second portion originating in the plug and diverging to the outlet where divergence is contributed to by changes in thickness of the outer radial wall and convergence of the central region. For at least a portion of the open flow channels, a central axis passing through the first and second portions is non-parallel with respect to the given direction of the flow.

  13. AUTO-EXPANSIVE FLOW

    EPA Science Inventory

    Physics suggests that the interplay of momentum, continuity, and geometry in outward radial flow must produce density and concomitant pressure reductions. In other words, this flow is intrinsically auto-expansive. It has been proposed that this process is the key to understanding...

  14. Freeze chromatography method and apparatus

    DOEpatents

    Scott, C.D.

    1987-04-16

    A freeze chromatography method and apparatus are provided which enable separation of the solutes contained in a sample. The apparatus includes an annular column construction comprising cylindrical inner and outer surfaces defining an annular passage therebetween. One of the surfaces is heated and the other cooled while passing an eluent through the annular passageway so that the eluent in contact with the cooled surface freezes and forms a frozen eluent layer thereon. A mixture of solutes dissolved in eluent is passed through the annular passageway in contact with the frozen layer so that the sample solutes in the mixture will tend to migrate either toward or away the frozen layer. The rate at which the mixture flows through the annular passageway is controlled so that the distribution of the sample solutes approaches that at equilibrium and thus a separation between the sample solutes occurs. 3 figs.

  15. Transition to turbulence in a tall annulus submitted to a radial temperature gradient

    NASA Astrophysics Data System (ADS)

    Lepiller, Valérie; Prigent, Arnaud; Dumouchel, Fabien; Mutabazi, Innocent

    2007-05-01

    We have investigated the transition to turbulence in a water flow confined inside a tall vertical cylindrical annulus submitted to a radial temperature gradient using the space-time diagrams technique. As soon as a small radial temperature gradient is applied to the annular flow, the radial stratification of density induces a torque that produces a large convection cell. The first instability of this flow occurs via a supercritical bifurcation and gives rise to axisymmetric rolls localized in the middle of the system. Just above the onset, the pattern contains spatiotemporal defects. For large values of the control parameter, we have observed a coexistence of turbulent bursts and laminar domains. We have measured the turbulent fraction and have performed a statistical analysis of the laminar and turbulent zones, and have found that they bear the main characteristics of spatiotemporal intermittency.

  16. Design and Numerical Simulation of Radial Inflow Turbine Volute

    NASA Astrophysics Data System (ADS)

    Shah, Samip P.; Channiwala, S. A.; Kulshreshtha, D. B.; Chaudhari, Gaurang

    2014-12-01

    The volute of a radial inflow turbine has to be designed to ensure that the desired rotor inlet conditions like absolute Mach number, flow angle etc. are attained. For the reasonable performance of vaneless volute turbine care has to be taken for reduction in losses at an appropriate flow angle at the rotor inlet, in the direction of volute, whose function is to convert gas energy into kinetic energy and direct the flow towards the rotor inlet at an appropriate flow angle with reduced losses. In literature it was found that the incompressible approaches failed to provide free vortex and uniform flow at rotor inlet for compressible flow regimes. So, this paper describes a non-dimensional design procedure for a vaneless turbine volute for compressible flow regime and investigates design parameters, such as the distribution of area ratio and radius ratio as a function of azimuth angle. The nondimensional design is converted in dimensional form for three different volute cross sections. A commercial computational fluid dynamics code is used to develop numerical models of three different volute cross sections. From the numerical models, losses generation in the different volutes are identified and compared. The maximum pressure loss coefficient for Trapezoidal cross section is 0.1075, for Bezier-trapezoidal cross section is 0.0677 and for circular cross section is 0.0438 near tongue region, which suggested that the circular cross section will give a better efficiency than other types of volute cross sections.

  17. High Performance Liquid Chromatography

    NASA Astrophysics Data System (ADS)

    Talcott, Stephen

    High performance liquid chromatography (HPLC) has many applications in food chemistry. Food components that have been analyzed with HPLC include organic acids, vitamins, amino acids, sugars, nitrosamines, certain pesticides, metabolites, fatty acids, aflatoxins, pigments, and certain food additives. Unlike gas chromatography, it is not necessary for the compound being analyzed to be volatile. It is necessary, however, for the compounds to have some solubility in the mobile phase. It is important that the solubilized samples for injection be free from all particulate matter, so centrifugation and filtration are common procedures. Also, solid-phase extraction is used commonly in sample preparation to remove interfering compounds from the sample matrix prior to HPLC analysis.

  18. Radial Force Balance in Plasma Hole and Role of Centrifugal Force

    NASA Astrophysics Data System (ADS)

    Yoshimura, Shinji; Kono, Mitsuo; Tanaka, Masayoshi

    2006-10-01

    A large-scale monopole vortex has been observed in a cylindrical magnetized plasma produced in the HYPER-I device at National Institute for Fusion Science, Japan. It is spontaneously formed with a deep density hole in its core and is referred to as plasma hole from the impression of the end-view image taken by a CCD camera. The flow-velocity field of the plasma hole exhibits two characteristic features: a supersonic azimuthal rotation caused by a strong radial electric field and an inward radial flow. Since the latter is not driven in axisymmetric collisionless invicid plasma, it implies finite viscosity of the plasma. It is revealed that quasi-neutrality breaking (δn/n˜10-3), which is the source of strong electric field, occurs in the hole region. To develop a deeper understanding on the structure of the flow-velocity field, we have analyzed the radial force balance including the nonlinear terms, i.e. the dynamic pressure due to radial flow and the centrifugal force. It is found that the centrifugal force dominates the radial electric field in the hole region, giving rise to a rigid rotor equilibrium which is similar to the fast rotation mode realized in pure electron plasmas.

  19. Combustion measurements from an impinging radial jet reattachment flame

    SciTech Connect

    Mohr, J.W.; Seyed-Yagoobi, J.; Page, R.H.

    1996-07-01

    A Radial Jet Reattachment (RJR) nozzle forces an air flow to reattach to a surface in a ring-like configuration and then flow outwardly and inwardly. A highly turbulent recirculation region above the nozzle produces high transport properties in the reattachment area and over a large area away from the centerline of reattachment. By introducing natural gas into the recirculation region, a Radial Jet Reattachment Combustion (RJRC) nozzle has demonstrated improved fuel/air mixing for use in impingement flame heating. To characterize the performance of RJRC nozzles, heat transfer, surface temperature, surface pressure, and exhaust gas measurements are reported, and comparisons are made with a conventional co-axial-flowing (Co-Ax) flame impingement nozzle. Total surface heat transfer rates for both nozzles show similar results, with the RJRC nozzle showing slightly better performance. The RJRC nozzle produces a very stable flame with a circumferentially symmetric surface temperature profile and low coefficients of pressure at the surface. In contrast, the Co-Ax nozzle has a less table flame with a non-symmetric surface temperature profile and produces surface pressure more than six times the pressures from the RJRC nozzle. Exhaust gas analysis shows very low production of Co and NO{sub x} for the RJRC nozzle, which also produces very little soot.

  20. Scaling laws for radial foil bearings

    NASA Astrophysics Data System (ADS)

    Honavara Prasad, Srikanth

    The effects of fluid pressurization, structural deformation of the compliant members and heat generation in foil bearings make the design and analysis of foil bearings very complicated. The complex fluid-structural-thermal interactions in foil bearings also make modeling efforts challenging because these phenomena are governed by highly non-linear partial differential equations. Consequently, comparison of various bearing designs require detailed calculation of the flow fields (velocities, pressures), bump deflections (structural compliance) and heat transfer phenomena (viscous dissipation in the fluid, frictional heating, temperature profile etc.,) resulting in extensive computational effort (time/hardware). To obviate rigorous computations and aid in feasibility assessments of foil bearings of various sizes, NASA developed the "rule of thumb" design guidelines for estimation of journal bearing load capacity. The guidelines are based on extensive experimental data. The goal of the current work is the development of scaling laws for radial foil bearings to establish an analytical "rule of thumb" for bearing clearance and bump stiffness. The use of scale invariant Reynolds equation and experimentally observed NASA "rule of thumb" yield scale factors which can be deduced from first principles. Power-law relationships between: a. Bearing clearance and bearing radius, and b. bump stiffness and bearing radius, are obtained. The clearance and bump stiffness values obtained from scaling laws are used as inputs for Orbit simulation to study various cases. As the clearance of the bearing reaches the dimensions of the material surface roughness, asperity contact breaks the fluid film which results in wear. Similarly, as the rotor diameter increases (requiring larger bearing diameters), the load capacity of the fluid film should increase to prevent dry rubbing. This imposes limits on the size of the rotor diameter and consequently bearing diameter. Therefore, this thesis aims to provide the upper and lower bounds for the developed scale laws in terms of the bearing diameter.

  1. Purification and characterization of transcribed RNAs using gel filtration chromatography.

    PubMed

    McKenna, Sean A; Kim, Insil; Puglisi, Elisabetta Viani; Lindhout, Darrin A; Aitken, Colin Echeverra; Marshall, R Andrew; Puglisi, Joseph D

    2007-01-01

    RNA synthesis using in vitro transcription by phage T7 RNA polymerase allows preparation of milligram quantities of RNA for biochemical, biophysical and structural investigations. Previous purification approaches relied on gel electrophoretic or gravity-flow chromatography methods. We present here a protocol for the in vitro transcription of RNAs and subsequent purification using fast-performance liquid chromatography. This protocol greatly facilitates production of RNA in a single day from transcription to purification. PMID:18079727

  2. Cooling characteristics of air cooled radial turbine blades

    NASA Astrophysics Data System (ADS)

    Sato, T.; Takeishi, K.; Matsuura, M.; Miyauchi, J.

    The cooling design and the cooling characteristics of air cooled radial turbine wheels, which are designed for use with the gas generator turbine for the 400 horse power truck gas turbine engine, are presented. A high temperature and high speed test was performed under aerodynamically similar conditions to that of the prototype engine in order to confirm the metal temperature of the newly developed integrated casting wheels constructed of the superalloys INCO 713C. The test results compared with the analytical value, which was established on the basis of the results of the heat transfer test and the water flow test, are discussed.

  3. Hydrodynamic effects in a misaligned radial face seal

    NASA Technical Reports Server (NTRS)

    Etsion, I.

    1978-01-01

    Hydrodynamic effects in a flat seal having an angular misalignment are analyzed, taking into account the radial variation in seal clearance. An analytical solution for axial force, restoring moment, and transverse moment is presented that covers the whole range from zero to full angular misalignment. Both low pressure seals with cavitating flow and high pressure seals with full fluid film are considered. Strong coupling is demonstrated between angular misalignment and transverse moment which leads the misalignment vector by 90 degrees. This transverse moment, which is entirely due to hydrodynamic effects, may be a significant factor in seal operating mechanism.

  4. Hydrodynamic effects in a misaligned radial face seal

    NASA Technical Reports Server (NTRS)

    Etsion, I.

    1977-01-01

    Hydrodynamic effects in a flat seal having an angular misalignment are analyzed, taking into account the radial variation in seal clearance. An analytical solution for axial force, restoring moment, and transverse moment is presented that covers the whole range from zero to full angular misalignment. Both low pressure seals with cavitating flow and high pressure seals with full fluid film are considered. Strong coupling is demonstrated between angular misalignment and transverse moment which leads the misalignment vector by 90 degrees. This transverse moment, which is entirely due to hydrodynamic effects, is a significant factor in the seal operating mechanism.

  5. Design of a Polymer-Based Radial Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Menon, Akanksha; Yee, Shannon

    2014-03-01

    Polymers possess desirable properties such as low thermal conductivity, low cost, and scalable processability as compared to inorganic materials. These characteristics make polymers attractive for thermoelectric (TE) applications. Current examples of polymer thin-film TE devices are limited to traditional rectangular/parallel plate geometries. The focus of this work is to investigate the effect of radial device geometry on TE performance. Each TE module consists of many divided discs of p- and n-type polymers on a thermally insulating circular substrate. In the center of the disc a channel of warm fluid flows as the source of heat, which creates a radial temperature gradient across the TE. Many discs can be stacked and connected electrically in series, thus generating an appreciable output voltage. In this work, analytic thermal and electrical models are developed to present an optimized device geometry for maximum power, maximum efficiency, and low /W scenarios. While the efficiency equation is identical to that for a rectangular geometry, the non-linear resistance of the radial device offers a higher power density and greater thermal insulation than traditional rectangular TEs. Graduate student at Georgia Tech

  6. Extending Paper Chromatography Inquiry

    ERIC Educational Resources Information Center

    Finson, Kevin

    2004-01-01

    One of the "good old" standard activities middle school students seem to enjoy is paper chromatography. The procedures and materials needed are relatively simple and the results can be colorful. All too often, the activity ends just after these colorful results are obtained, cutting short the potential it holds for some further inquiry. With some

  7. Effect of blade outlet angle on radial thrust of single-blade centrifugal pump

    NASA Astrophysics Data System (ADS)

    Nishi, Y.; Fukutomi, J.; Fujiwara, R.

    2012-11-01

    Single-blade centrifugal pumps are widely used as sewage pumps. However, a large radial thrust acts on a single blade during pump operation because of the geometrical axial asymmetry of the impeller. This radial thrust causes vibrations of the pump shaft, reducing the service life of bearings and shaft seal devices. Therefore, to ensure pump reliability, it is necessary to quantitatively understand the radial thrust and clarify the behavior and generation mechanism. This study investigated the radial thrust acting on two kinds of single-blade centrifugal impellers having different blade outlet angles by experiments and computational fluid dynamics (CFD) analysis. Furthermore, the radial thrust was modeled by a combination of three components, inertia, momentum, and pressure, by applying an unsteady conservation of momentum to this impeller. As a result, the effects of the blade outlet angle on both the radial thrust and the modeled components were clarified. The total head of the impeller with a blade outlet angle of 16 degrees increases more than the impeller with a blade outlet angle of 8 degrees at a large flow rate. In this case, since the static pressure of the circumference of the impeller increases uniformly, the time-averaged value of the radial thrust of both impellers does not change at every flow rate. On the other hand, since the impeller blade loading becomes large, the fluctuation component of the radial thrust of the impeller with the blade outlet angle of 16 degrees increases. If the blade outlet angle increases, the fluctuation component of the inertia component will increase, but the time-averaged value of the inertia component is located near the origin despite changes in the flow rate. The fluctuation component of the momentum component becomes large at all flow rates. Furthermore, although the time-averaged value of the pressure component is almost constant, the fluctuation component of the pressure component becomes large at a large flow rate. In addition to the increase of the fluctuation component of this pressure component, because the fluctuation component of the inertia and momentum components becomes large (as mentioned above), the radial thrust increases at a large flow rate, as is the case for the impeller with a large blade outlet angle.

  8. Modern Thin-Layer Chromatography.

    ERIC Educational Resources Information Center

    Poole, Colin F.; Poole, Salwa K.

    1989-01-01

    Some of the important modern developments of thin-layer chromatography are introduced. Discussed are the theory and instrumentation of thin-layer chromatography including multidimensional and multimodal techniques. Lists 53 references. (CW)

  9. Radial/axial power divider/combiner

    NASA Technical Reports Server (NTRS)

    Vaddiparty, Yerriah P. (Inventor)

    1987-01-01

    An electromagnetic power divider/combiner comprises N radial outputs (31) having equal powers and preferably equal phases, and a single axial output (20). A divider structure (1) and a preferably identical combiner structure (2) are broadside coupled across a dielectric substrate (30) containing on one side the network of N radial outputs (31) and on its other side a set of N equispaced stubs (42) which are capacitively coupled through the dielectric substrate (30) to the N radial outputs (31). The divider structure (1) and the combiner structure (2) each comprise a dielectric disk (12, 22, respectively) on which is mounted a set of N radial impedance transformers (14, 24, respectively). Gross axial coupling is determined by the thickness of the dielectric layer (30). Rotating the disks (12, 22) with respect to each other effectuates fine adjustment in the degree of axial coupling.

  10. Polarizability of radially anisotropic elliptic inclusion

    NASA Astrophysics Data System (ADS)

    Rimpilinen, T.; Walln, H.; Sihvola, A.

    2016-01-01

    This article discusses a two-dimensional electrostatic scattering problem where an elliptic inclusion is suspended in a homogeneous background and impinged by an electric field which is uniform and static. The novelty of the discussion stems from the inclusion's material parameters. The material of the inclusion is assumed to be axially anisotropic, so that the axis of anisotropy aligns itself with the radial unit vector of the elliptic coordinate system. Similar varieties of anisotropy have been formerly referred to as radial anisotropy, and the same term is employed herein. The radially anisotropic elliptic inclusions are studied with an analytic method. The validation is likewise analytic. The validation method compares the new results with the results for radially anisotropic circles and homogeneous two-dimensional needles. The elliptic inclusion is found to facilitate both cloaking and field concentration.

  11. Radial Velocity Fluctuations of RZ Psc

    NASA Astrophysics Data System (ADS)

    Potravnov, I. S.; Gorynya, N. A.; Grinin, V. P.; Minikulov, N. Kh.

    2014-12-01

    The behavior of the radial velocity of the UX Ori type star RZ Psc is studied. The existence of an inner cavity with a radius of about 0.7 a.u. in the circumstellar disk of this star allows to suggest the presence of a companion. A study of the radial velocity of RZ Psc based on our own measurements and published data yields no periodic component in its variability. The two most accurate measurements of V r , based on high resolution spectra obtained over a period of three months, show that the radial velocity is constant over this time interval to within 0.5 km/s. This imposes a limit of M p ≤10 M Jup on the mass of the hypothetical companion. Possible reasons for the observed strong fluctuations in the radial velocity of this star are discussed.

  12. Radial transport with perturbed magnetic field

    SciTech Connect

    Hazeltine, R. D.

    2015-05-15

    It is pointed out that the viscosity coefficient describing radial transport of toroidal angular momentum is proportional to the second power of the gyro-radius—like the corresponding coefficients for particle and heat transport—regardless of any geometrical symmetry. The observation is widely appreciated, but worth emphasizing because some literature gives the misleading impression that asymmetry can allow radial moment transport in first-order.

  13. Complex Elbow Instability: Radial Head and Coronoid.

    PubMed

    Kovacevic, David; Vogel, Laura A; Levine, William N

    2015-11-01

    A standardized and systematic approach for the management of an acute complex elbow dislocation involving the radial head and coronoid will maximize clinical outcomes. The cornerstones of surgical management include primary restoration of the ulnohumeral joint by reduction of the intact joint or coronoid fracture fixation, followed by radial head fixation or replacement. The lateral ulnar collateral ligament complex is then repaired before assessing elbow stability within a functional sagittal arc of motion. PMID:26498544

  14. Effects of design parameters on the radial force of percutaneous aortic valve stents.

    PubMed

    Kumar, Gideon V Praveen; Mathew, Lazar

    2010-01-01

    Valve stents are small cylindrical structures introduced in stenosed valves to replace them and restore blood flow. High radial force has become an essential feature of these stents. The primary aim of this investigation was to investigate the effects of varying stent "design parameters" on its radial force by using the finite element method (FEM). The improved model design was carried out to meet the functional and surgical requirements. The finite element model to evaluate radial force of stent was dependant on various design parameters. The results show that amplitude was the dominant parameter in this study. Increasing either strut circumference or thickness generally improved radial force of stent. However, increasing either amplitude or radius of curvature generally weakened it. In conclusion, FEM can quantify the compressive mechanical property of stent and help designers to optimize stent systems. PMID:20347800

  15. Origin of the Radial Interplanetary Magnetic Field and Its Effects on the Magnetospheric System

    NASA Astrophysics Data System (ADS)

    Shue, J. H.

    2014-12-01

    The orientation of the interplanetary magnetic field (IMF) is usually aligned with a spiral form. Sometimes this orientation becomes radial, i.e., the solar wind plasma flowing in align with the IMF. Under this circumstance, the magnetospheric system, including the bow shock, magnetosheath, magnetopause, and magnetosphere, responds to the radial IMF in a way that is different from the other orientations. For example, the magnetopause moves outward and the bow shock moves inward, resulting a thin magnetosheath. Although the magnetospheric state for radial IMF is generally quiet, active local field-aligned currents can be observed in the high-latitude ionosphere. In this presentation, the current understandings and future perspectives on the origin of the radial IMF and its effects on the magnetospheric system will be reviewed.

  16. High Performance Thin Layer Chromatography.

    ERIC Educational Resources Information Center

    Costanzo, Samuel J.

    1984-01-01

    Clarifies where in the scheme of modern chromatography high performance thin layer chromatography (TLC) fits and why in some situations it is a viable alternative to gas and high performance liquid chromatography. New TLC plates, sample applications, plate development, and instrumental techniques are considered. (JN)

  17. Analytical design of an advanced radial turbine

    SciTech Connect

    Large, G.D.; Finger, D.G.; Linder, C.G.

    1981-02-01

    The analytical design of an advanced radial turbine, which is part of an optimum ceramic radial inflow, single-stage turbine system for an advanced automotive gas turbine engine is reported. The turbine study program is based on an advanced gas turbine cycle, 100.67-kW (135-shp) engine for use in a 1588-kg (3500-lb) automobile, with a specific fuel consumption of 0.227 kg/kW-hr (0.373 lb/hp-hr). Utilization of high turbine cycle temperatures of 1370/sup 0/C and ceramic materials are prime features of this study. The program objective was to investigate the effects of tip speed, non-radial rotor blading, inducer-to-exducer work split, and deswirl vanes on the system efficiency and mechanical reliability of a single-stage, ceramic, radial turbine designed to meet the performance requirements of an advanced automotive gas turbine cycle. Analysis results indicate that, based on projected 1983 aerodynamic performance and ceramic material properties, radial blade rotor configurations with a tip speed of 701 m/sec (2300 fps) are feasible and satisfy the goals of 87.0% system efficiency and 0.9999 cumulative probability of success mechanically. As compared with the blade stress complications of nonradial rotor configurations, from aerodynamic, mechanical, and off-design considerations, the radial-blade rotor appears to offer the lowest overall risk and is the optimum configuration considered in this study.

  18. Sequential Assembly of Flagellar Radial Spokes

    PubMed Central

    Diener, Dennis R.; Yang, Pinfen; Geimer, Stefan; Cole, Douglas G.; Sale, Winfield S.; Rosenbaum, Joel L.

    2013-01-01

    The unicellular alga Chlamydomonas can assemble two 10 ?m flagella in one hour from proteins synthesized in the cell body. Targeting and transporting these proteins to the flagella are simplified by preassembly of macromolecular complexes in the cell body. Radial spokes are flagellar complexes that are partially assembled in the cell body before entering the flagella. On the axoneme, radial spokes are T shaped structures with a head of 5 proteins and a stalk of 18 proteins that sediment together at 20S. In the cell body, radial spokes are partially assembled; about half of the radial spoke proteins (RSPs) form a 12S complex. In mutants lacking a single radial spoke protein, smaller spoke subassemblies were identified. When extracts from two such mutants were mixed in vitro the 12S complex was assembled from several smaller complexes demonstrating that portions of the stepwise assembly of radial spoke assembly can be carried out in vitro to elucidate the order of spoke assembly in the cell body. PMID:21692193

  19. Radial tidal current field in a semi-enclosed rectangular basin: formation and evolution

    NASA Astrophysics Data System (ADS)

    Qian, Xuesheng; Chen, Yongping; Zhang, Changkuan; Pan, Yi; Das, Himangshu

    2015-07-01

    The radial tidal current field accounts for the formation of the radial sand ridges in the South Yellow Sea. Understanding the formation and evolution of this radial tidal current field is vital to assessing the morphodynamic features in the area. A semi-enclosed rectangular basin with and without a coastal barrier was schematized from the topography of the Bohai Sea and Yellow Sea. The 2D tidal current field in this basin was simulated using the DELFT3D-FLOW model. The concept of tidal wave refraction, which highlights the effect of the sloped or stepped submarine topography on the propagation of the tidal waves, was introduced to explain the formation of the radial tidal current field. Under the effect of tidal wave refraction, co-phase lines of the counterclockwise rotating tidal wave and incident tidal wave are transformed into clockwise and counterclockwise deflections, respectively, leading to the convergence and divergence of the flow field. Regardless of whether a coastal barrier exists or not, the outer radial tidal current field might emerge over certain topography. The responses of the radial tidal current field in this basin to the environmental variations such as coastline changes and bottom erosions were discussed. Results show that local protrusion near the focal point of the radial tidal current field will have limited effects on the location of the tidal system. However, a remarkable shift of the amphidromic point toward the entrance and central axis of this basin and a movement of the focal point of the radial tidal current field toward the entrance could be caused by the significant seaward coastline advance and submarine slope erosion.

  20. The effects of radiation drag on radial, relativistic hydromagnetic winds

    NASA Astrophysics Data System (ADS)

    Li, Zhi-Yun; Begelman, Mitchell C.; Chiueh, Tzihong

    1992-01-01

    The effects of drag on an idealized relativistic MHD wind of radial geometry are studied. The astrophysical motivation is to understand the effects of radiation drag on the dynamics of a jet or wind passing through the intense radiation field of an accreting compact object. From a critical point analysis, it is found that a slow magnetosonic point can appear in a dragged flow even in the absence of gravitational force, as a result of a balance between the drag force and the combination of thermal pressure and centrifugal forces. As in the undragged case, the Alfven point does not impose any constraints on the flow. Although it is formally possible for a dragged flow to possess more than one fast magnetosonic point, it is shown that this is unlikely in practice. In the limit of a 'cold', centrifugally driven flow, it is shown that the fast magnetosonic point moves to infinite radius, just as in the drag-free case. For a given mass flux, the total energy output carried to infinity, and the final partition between the kinetic energy and the Poynting flux, are the same for the dragged and the drag-free flows. The main effects of radiation drag are to increase the amount of energy and angular momentum extracted from the source and to redistribute the regions where acceleration occurs in the flow. This is accomplished through the storage and release of magnetic energy, as a result of additional winding and compression of the field caused by the action of the drag. For a relativistic wind, the dissipated energy can exceed the final kinetic energy of the flow and may be comparable to the total flow energy (which is dominated by Poynting flux). The energy lost to radiation drag will appear as a Doppler-boosted beam of scattered radiation, which could dominate the background radiation if the flow is well-collimated.

  1. Effects of secondary flow on heat transfer in rotating passages

    NASA Astrophysics Data System (ADS)

    Moore, Joan G.; Moore, John

    1990-02-01

    Secondary flow in rotating cooling passages of jet engine turbine rotors is considered. A Navier-Stokes calculation procedure for turbulent flow is used to compute flow development in a radially outward flow channel, round a sharp 180 degree bend, and in the radially inward flow channel downstream. Areas of high and low heat transfer are explained by secondary flow development and quantitative results show regions of design interest.

  2. Waves in Radial Gravity Using Magnetic Fluid

    NASA Technical Reports Server (NTRS)

    Ohlsen, D. R.; Hart, J. E.; Weidman, P. D.

    1999-01-01

    Terrestrial laboratory experiments studying various fluid dynamical processes are constrained, by being in an Earth laboratory, to have a gravitational body force which is uniform and unidirectional. Therefore fluid free-surfaces are horizontal and flat. Such free surfaces must have a vertical solid boundary to keep the fluid from spreading horizontally along a gravitational potential surface. In atmospheric, oceanic, or stellar fluid flows that have a horizontal scale of about one-tenth the body radius or larger, sphericity is important in the dynamics. Further, fluids in spherical geometry can cover an entire domain without any sidewall effects, i.e. have truly periodic boundary conditions. We describe spherical body-force laboratory experiments using ferrofluid. Ferrofluids are dilute suspensions of magnetic dipoles, for example magnetite particles of order 10 nm diameter, suspended in a carrier fluid. Ferrofluids are subject to an additional body force in the presence of an applied magnetic field gradient. We use this body force to conduct laboratory experiments in spherical geometry. The present study is a laboratory technique improvement. The apparatus is cylindrically axisymmetric. A cylindrical ceramic magnet is embedded in a smooth, solid, spherical PVC ball. The geopotential field and its gradient, the body force, were made nearly spherical by careful choice of magnet height-to-diameter ratio and magnet size relative to the PVC ball size. Terrestrial gravity is eliminated from the dynamics by immersing the "planet" and its ferrofluid "ocean" in an immiscible silicone oil/freon mixture of the same density. Thus the earth gravity is removed from the dynamics of the ferrofluid/oil interface and the only dynamically active force there is the radial magnetic gravity. The entire apparatus can rotate, and waves are forced on the ferrofluid surface by exterior magnets. The biggest improvement in technique is in the wave visualization. Fluorescing dye is added to the oil/freon mixture and an argon ion laser generates a horizontal light that can be scanned vertically. Viewed from above, the experiment is a black circle with wave deformations surrounded by a light background. A contour of the image intensity at any light sheet position gives the surface of the ferrofluid "ocean" at that "latitude". Radial displacements of the waves as a function of longitude are obtained by subtracting the contour line positions from a no-motion contour at that laser sheet latitude. The experiments are run by traversing the forcing magnet with the laser sheet height fixed and images are frame grabbed to obtain a time-series at one latitude. The experiment is then re-run with another laser-sheet height to generate a full picture of the three-dimensional wave structure in the upper hemisphere of the ball as a function of time. We concentrate here on results of laboratory studies of waves that are important in Earth's atmosphere and especially the ocean. To get oceanic scaling in the laboratory, the experiment must rotate rapidly (4-second rotation period) so that the wave speed is slow compared to the planetary rotation speed as in the ocean. In the Pacific Ocean, eastward propagating Kelvin waves eventually run into the South American coast. Theory predicts that some of the wave energy should scatter into coastal-trapped Kelvin waves that propagate north and south along the coast. Some of this coastal wave energy might then scatter into mid-latitude Rossby waves that propagate back westward. Satellite observations of the Pacific Ocean sea-surface temperature and height seem to show signatures of westward propagating mid-latitude Rossby waves, 5 to 10 years after the 1982-83 El Nino. The observational data is difficult to interpret unambiguously owing to the large range of motions that fill the ocean at shorter timescales. This series of reflections giving eastward, north- ward, and then westward traveling waves is observed cleanly in the laboratory experiments, confirming the theoretical expectations.

  3. Waves in Radial Gravity Using Magnetic Fluid

    NASA Technical Reports Server (NTRS)

    Ohlsen, D. R.; Hart, J. E.; Weidman, P. D.

    1999-01-01

    Terrestrial laboratory experiments studying various fluid dynamical processes are constrained, by being in an Earth laboratory, to have a gravitational body force which is uniform and unidirectional. Therefore fluid free-surfaces are horizontal and flat. Such free surfaces must have a vertical solid boundary to keep the fluid from spreading horizontally along a gravitational potential surface. In atmospheric, oceanic, or stellar fluid flows that have a horizontal scale of about one-tenth the body radius or larger, sphericity is important in the dynamics. Further, fluids in spherical geometry can cover an entire domain without any sidewall effects, i.e. have truly periodic boundary conditions. We describe spherical body-force laboratory experiments using ferrofluid. Ferrofluids are dilute suspensions of magnetic dipoles, for example magnetite particles of order 10 nm diameter, suspended in a carrier fluid. Ferrofluids are subject to an additional body force in the presence of an applied magnetic field gradient. We use this body force to conduct laboratory experiments in spherical geometry. The present study is a laboratory technique improvement. The apparatus is cylindrically axisymmetric. A cylindrical ceramic magnet is embedded in a smooth, solid, spherical PVC ball. The geopotential field and its gradient, the body force, were made nearly spherical by careful choice of magnet height-to-diameter ratio and magnet size relative to the PVC ball size. Terrestrial gravity is eliminated from the dynamics by immersing the "planet" and its ferrofluid "ocean" in an immiscible silicone oil/freon mixture of the same density. Thus the earth gravity is removed from the dynamics of the ferrofluid/oil interface and the only dynamically active force there is the radial magnetic gravity. The entire apparatus can rotate, and waves are forced on the ferrofluid surface by exterior magnets. The biggest improvement in technique is in the wave visualization. Fluorescing dye is added to the oil/freon mixture and an argon ion laser generates a horizontal light that can be scanned vertically. Viewed from above, the experiment is a black circle with wave deformations surrounded by a light background. A contour of the image intensity at any light sheet position gives the surface of the ferrofluid "ocean" at that "latitude". Radial displacements of the waves as a function of longitude are obtained by subtracting the contour line positions from a no-motion contour at that laser sheet latitude. The experiments are run by traversing the forcing magnet with the laser sheet height fixed and images are frame grabbed to obtain a time-series at one latitude. The experiment is then re-run with another laser-sheet height to generate a full picture of the three-dimensional wave structure in the upper hemisphere of the ball as a function of time. We concentrate here on results of laboratory studies of waves that are important in Earth's atmosphere and especially the ocean. To get oceanic scaling in the laboratory, the experiment must rotate rapidly (4-second rotation period) so that the wave speed is slow compared to the planetary rotation speed as in the ocean. In the Pacific Ocean, eastward propagating Kelvin waves eventually run into the South American coast. Theory predicts that some of the wave energy should scatter into coastal-trapped Kelvin waves that propagate north and south along the coast. Some of this coastal wave energy might then scatter into mid-latitude Rossby waves that propagate back westward. Satellite observations of the Pacific Ocean sea-surface temperature and height seem to show signatures of westward propagating mid-latitude Rossby waves, 5 to 10 years after the 1982-83 El Nino. The observational data is difficult to interpret unambiguously owing to the large range of motions that fill the ocean at shorter timescales. This series of reflections giving eastward, north- ward, and then westward traveling waves is observed cleanly in the laboratory experiments, confirming the theoretical expectations

  4. [Elbow dislocation with ipsilateral proximal radial shaft fracture and radial head dislocation].

    PubMed

    Köhn, N; Mendel, T; Ullrich, B W

    2015-11-01

    Elbow dislocation with ipsilateral proximal radial shaft fracture and dislocated radial head is a rarely described injury. In this article we present the case of a 23-year-old man with this injury. After the initial diagnostics, the radial shaft fracture was osteosynthetically fixed, whereby the anatomical positions of all parts of the elbow joint were correctly aligned and the medial collateral ligament was reconstructed. After 4.5 months the radial shaft fracture was healed with nearly complete functional recovery of the upper extremity. Thus, a good outcome can be expected when all aspects of bony and ligamentous injuries are accurately addressed. PMID:25666185

  5. Magnetic Resonance Microimaging and Numerical Simulations of Velocity Fields Inside Enlarged Flow Cells Used for Coupled NMR Microseparations

    PubMed Central

    Zhang, Xiaofeng; Webb, Andrew G.

    2009-01-01

    The coupling of various chemical microseparation methods with small-scale NMR detection is a growing area in analytical chemistry. The formation of enlarged flow cells within the active volume of the NMR detector can significantly increase the coil filling factor and hence the signal-to-noise ratio of the NMR spectra. However, flow cells can also lead to deterioration of the separation efficiency due to the development of complex flow patterns, the form of which depend on the particular geometry of the flow cell and the flow rate used. In this study, we investigated the flow characteristics in different flow cell geometries relevant to the coupling of capillary liquid chromatography and NMR. Computational fluid dynamics was used to simulate fluid flow inside flow cells with a volume of ~ 1 L. Magnetic resonance microimaging was used to measure experimentally the velocity fields inside these flow cells. The results showed good agreement between experiment and simulation and demonstrated that a relatively gradual expansion and contraction is necessary to avoid areas of weak recirculation and strong radial velocities, both of which can potentially compromise separation efficiency. PMID:15732916

  6. Determination of alkylphenols by gas chromatography, elution liquid chromatography, and gel permeation chromatography

    SciTech Connect

    Wittmann, S.; Decsy, Z.; Regensperger, S.; Pudmer, E.

    1984-01-01

    The separation and determination of groups of alkylphenols with C/sub 15/-C/sub 33/ isoalkane chains by gas chromatography, elution liquid chromatography, and gel permeation chromatography are described. Paraffinic hydrocarbons, monoalkylphenols, dialkylphenols, and bis(hydroxyphenyl)alkanes were identified in industrial alkylphenols by mass spectrometry. 7 references, 3 figures, 2 tables.

  7. Classification of volcanoes of the Kane Patera Quadrangle of Io: Proportions of lava flows and pyroclastic flows

    NASA Technical Reports Server (NTRS)

    Elston, W. E.

    1984-01-01

    Voyager 1 images show 14 volcanic centers wholly or partly within the Kane Patera quadrangle of Io, which are divided into four major classes: (1) shield with parallel flows; (2) shield with early radial fan shapd flows; (3) shield with radial fan shaped flows, surfaces of flows textured with longitudinal ridges; and (4) depression surrounded by plateau-forming scarp-bounded, untextured deposits. The interpretation attempted here hinges largely on the ability to distinguish lava flows from pyroclastic flows by remote sensing.

  8. Cooled High-temperature Radial Turbine Program 2

    NASA Technical Reports Server (NTRS)

    Snyder, Philip H.

    1991-01-01

    The objective of this program was the design and fabrication of a air-cooled high-temperature radial turbine (HTRT) intended for experimental evaluation in a warm turbine test facility at the LeRC. The rotor and vane were designed to be tested as a scaled version (rotor diameter of 14.4 inches diameter) of a 8.021 inch diameter rotor designed to be capable of operating with a rotor inlet temperature (RIT) of 2300 F, a nominal mass flow of 4.56 lbm/sec, a work level of equal or greater than 187 Btu/lbm, and efficiency of 86 percent or greater. The rotor was also evaluated to determine it's feasibility to operate at 2500 F RIT. The rotor design conformed to the rotor blade flow path specified by NASA for compatibility with their test equipment. Fabrication was accomplished on three rotors, a bladeless rotor, a solid rotor, and an air-cooled rotor.

  9. Variable area radial turbine fabrication and test program

    NASA Technical Reports Server (NTRS)

    Rogo, C.

    1986-01-01

    A variable area radial turbine with a moveable nozzle sidewall was experimentally evaluated. The turbine was designed for an advanced variable capacity gas turbine rotorcraft engine. The turbine has a mass flow rate of 2.27 kg/sec (5.0 lbs/sec), and a rotor inlet temperature of 1477K (2200 F). Testing was conducted at a reduced inlet temperature, but the aerodynamic parameters and Reynolds numbers were duplicated. Overall performance was obtained for a range of nozzle areas from 50% to 100% of the maximum area. The test program determined the effect on performance of: (1) Moving the hub or shroud sidewall; (2) Sidewall-vane clearance leakage; (3) Vaneless space geometry change; and (4) Nozzle cooling flows. Data were obtained for a range of pressure ratios and speeds and are presented in a number of performance maps.

  10. Computer program for design analysis of radial-inflow turbines

    NASA Technical Reports Server (NTRS)

    Glassman, A. J.

    1976-01-01

    A computer program written in FORTRAN that may be used for the design analysis of radial-inflow turbines was documented. The following information is included: loss model (estimation of losses), the analysis equations, a description of the input and output data, the FORTRAN program listing and list of variables, and sample cases. The input design requirements include the power, mass flow rate, inlet temperature and pressure, and rotational speed. The program output data includes various diameters, efficiencies, temperatures, pressures, velocities, and flow angles for the appropriate calculation stations. The design variables include the stator-exit angle, rotor radius ratios, and rotor-exit tangential velocity distribution. The losses are determined by an internal loss model.

  11. Experimental evaluation of a translating nozzle sidewall radial turbine

    NASA Technical Reports Server (NTRS)

    Roelke, Richard J.; Rogo, Casimir

    1987-01-01

    Studies have shown that reduced specific fuel consumption of rotorcraft engines can be achieved with a variable capacity engine. A key component in such an engine in a high-work, high-temperature variable geometry gas generator turbine. An optimization study indicated that a radial turbine with a translating nozzle sidewall could produce high efficiency over a wide range of engine flows but substantiating data were not available. An experimental program with Teledyne CAE, Toledo, Ohio was undertaken to evaluate the moving sidewall concept. A variety of translating nozzle sidewall turbine configurations were evaluated. The effects of nozzle leakage and coolant flows were also investigated. Testing was done in warm air (121 C). The results of the contractual program were summarized.

  12. A mini axial and a permanent maglev radial heart pump.

    PubMed

    Qian, Kun-Xi; Ru, Wei-Min; Wang, Hao; Jing, Teng

    2007-01-01

    The implantability and durability have been for decades the focus of artificial heart R&D. A mini axial and a maglev radial pump have been developed to meet with such requirements.The mini axial pump weighing 27g (incl.5g rotor) has an outer diameter of 21mm and a length of 10mm in its largest point, but can produce a maximal blood flow of 6l/min with 50mmHg pressure increase. Therefore, it is suitable for the patients of 40-60kg body weight. For other patients of 60-80kg or 80-100kg body weight, the mini axial pumps of 23mm and 25mm outer diameter had been developed before, these devices were acknowledged to be the world smallest LVADs by Guinness World Record Center in 2004.The permanent maglev radial pump weighing 150g is a shaft-less centrifugal pump with permanent magnetic bearings developed by the author. It needs no second coil for suspension of the rotor except the motor coil, different from all other maglev pumps developed in USA, Japan, European, etc. Thus no detecting and controlling systems as well as no additional power supply for maglev are necessary. The pump can produce a blood flow up to as large as 10l/min against 100mmHg pressure.An implantable and durable blood pump will be a viable alternative to natural donor heart for transplantation. PMID:19662120

  13. Numerical modeling of elution peak profiles in supercritical fluid chromatography. Part I-Elution of an unretained tracer

    SciTech Connect

    Kaczmarski, Krzysztof; Guiochon, Georges A

    2010-01-01

    When chromatography is carried out with high-density carbon dioxide as the main component of the mobile phase (a method generally known as 'supercritical fluid chromatography' or SFC), the required pressure gradient along the column is moderate. However, this mobile phase is highly compressible and, under certain experimental conditions, its density may decrease significantly along the column. Such an expansion absorbs heat, cooling the column, which absorbs heat from the outside. The resulting heat transfer causes the formation of axial and radial gradients of temperature that may become large under certain conditions. Due to these gradients, the mobile phase velocity and most physico-chemical parameters of the system (viscosity, diffusion coefficients, etc.) are no longer constant throughout the column, resulting in a loss of column efficiency, even at low flow rates. At high flow rates and in serious cases, systematic variations of the retention factors and the separation factors with increasing flow rates and important deformations of the elution profiles of all sample components may occur. The model previously used to account satisfactorily for the effects of the viscous friction heating of the mobile phase in HPLC is adapted here to account for the expansion cooling of the mobile phase in SFC and is applied to the modeling of the elution peak profiles of an unretained compound in SFC. The numerical solution of the combined heat and mass balance equations provides temperature and pressure profiles inside the column, and values of the retention time and efficiency for elution of this unretained compound that are in excellent agreement with independent experimental data.

  14. Fluctuating Pressure Environments and Hydrodynamic Radial Force Mitigation for a Two Blade Unshrouded Inducer

    NASA Technical Reports Server (NTRS)

    Mulder, Andrew; Skelley, Stephen

    2011-01-01

    Fluctuating pressure data from water flow testing of an unshrouded two blade inducer revealed a cavitation induced oscillation with the potential to induce a radial load on the turbopump shaft in addition to other more traditionally analyzed radial loads. Subsequent water flow testing of the inducer with a rotating force measurement system confirmed that the cavitation induced oscillation did impart a radial load to the inducer. After quantifying the load in a baseline configuration, two inducer shroud treatments were selected and tested to reduce the cavitation induced load. The first treatment was to increase the tip clearance, and the second was to introduce a circumferential groove near the inducer leading edge. Increasing the clearance resulted in a small load decrease along with some steady performance degradation. The groove greatly reduced the hydrodynamic load with little to no steady performance loss. The groove did however generate some new, relatively high frequency, spatially complex oscillations to the environment.

  15. Instrumentation for analytical scale supercritical fluid chromatography.

    PubMed

    Berger, Terry A

    2015-11-20

    Analytical scale supercritical fluid chromatography (SFC) is largely a sub-discipline of high performance liquid chromatography (HPLC), in that most of the hardware and software can be used for either technique. The aspects that separate the 2 techniques stem from the use of carbon dioxide (CO2) as the main component of the mobile phase in SFC. The high compressibility and low viscosity of CO2 mean that pumps, and autosamplers designed for HPLC either need to be modified or an alternate means of dealing with compressibility needs to be found. The inclusion of a back pressure regulator and a high pressure flow cell for any UV-Vis detector are also necessary. Details of the various approaches, problems and solutions are described. Characteristics, such as adiabatic vs. isothermal compressibility, thermal gradients, and refractive index issues are dealt with in detail. PMID:26212805

  16. Radial velocity studies of cool stars.

    PubMed

    Jones, Hugh R A; Barnes, John; Tuomi, Mikko; Jenkins, James S; Anglada-Escude, Guillem

    2014-04-28

    Our current view of exoplanets is one derived primarily from solar-like stars with a strong focus on understanding our Solar System. Our knowledge about the properties of exoplanets around the dominant stellar population by number, the so-called low-mass stars or M dwarfs, is much more cursory. Based on radial velocity discoveries, we find that the semi-major axis distribution of M dwarf planets appears to be broadly similar to those around more massive stars and thus formation and migration processes might be similar to heavier stars. However, we find that the mass of M dwarf planets is relatively much lower than the expected mass dependency based on stellar mass and thus infer that planet formation efficiency around low-mass stars is relatively impaired. We consider techniques to overcome the practical issue of obtaining good quality radial velocity data for M dwarfs despite their faintness and sustained activity and emphasize (i) the wavelength sensitivity of radial velocity signals, (ii) the combination of radial velocity data from different experiments for robust detection of small amplitude signals, and (iii) the selection of targets and radial velocity interpretation of late-type M dwarfs should consider H? behaviour. PMID:24664922

  17. Helical antimicrobial polypeptides with radial amphiphilicity.

    PubMed

    Xiong, Menghua; Lee, Michelle W; Mansbach, Rachael A; Song, Ziyuan; Bao, Yan; Peek, Richard M; Yao, Catherine; Chen, Lin-Feng; Ferguson, Andrew L; Wong, Gerard C L; Cheng, Jianjun

    2015-10-27

    ?-Helical antimicrobial peptides (AMPs) generally have facially amphiphilic structures that may lead to undesired peptide interactions with blood proteins and self-aggregation due to exposed hydrophobic surfaces. Here we report the design of a class of cationic, helical homo-polypeptide antimicrobials with a hydrophobic internal helical core and a charged exterior shell, possessing unprecedented radial amphiphilicity. The radially amphiphilic structure enables the polypeptide to bind effectively to the negatively charged bacterial surface and exhibit high antimicrobial activity against both gram-positive and gram-negative bacteria. Moreover, the shielding of the hydrophobic core by the charged exterior shell decreases nonspecific interactions with eukaryotic cells, as evidenced by low hemolytic activity, and protects the polypeptide backbone from proteolytic degradation. The radially amphiphilic polypeptides can also be used as effective adjuvants, allowing improved permeation of commercial antibiotics in bacteria and enhanced antimicrobial activity by one to two orders of magnitude. Designing AMPs bearing this unprecedented, unique radially amphiphilic structure represents an alternative direction of AMP development; radially amphiphilic polypeptides may become a general platform for developing AMPs to treat drug-resistant bacteria. PMID:26460016

  18. Radial Tunnel Syndrome, Diagnostic and Treatment Dilemma.

    PubMed

    Moradi, Ali; Ebrahimzadeh, Mohammad H; Jupiter, Jess B

    2015-07-01

    Radial tunnel syndrome is a disease which we should consider it in elbow and forearm pains. It is diagnosed with lateral elbow and dorsal forearm pain may radiate to the wrist and dorsum of the fingers. The disease is more prevalent in women with the age of 30 to 50 years old. It occurs by intermittent compression on the radial nerve from the radial head to the inferior border of the supinator muscle, without obvious extensor muscle weakness. Compression could happen in five different sites but the arcade of Frose is the most common area that radial nerve is compressed. To diagnosis radial tunnel syndrome, clinical examination is more important than paraclinic tests such as electrodiagnsic test and imaging studies. The exact site of the pain which can more specified by rule of nine test and weakness of the third finger and wrist extension are valuable physical exams to diagnosis. MRI studies my show muscle edema or atrophy along the distribution of the posterior interosseous nerve. Although non-surgical treatments such as rest, NSAIDs, injections and physiotherapy do not believe to have permanent relief, but it is justify undergoing them before surgery. Surgery could diminish pain and symptoms in 67 to 93 percents of patients completely. PMID:26213698

  19. Radial Tunnel Syndrome, Diagnostic and Treatment Dilemma

    PubMed Central

    Moradi, Ali; Ebrahimzadeh, Mohammad H; Jupiter, Jess B

    2015-01-01

    Radial tunnel syndrome is a disease which we should consider it in elbow and forearm pains. It is diagnosed with lateral elbow and dorsal forearm pain may radiate to the wrist and dorsum of the fingers. The disease is more prevalent in women with the age of 30 to 50 years old. It occurs by intermittent compression on the radial nerve from the radial head to the inferior border of the supinator muscle, without obvious extensor muscle weakness. Compression could happen in five different sites but the arcade of Frose is the most common area that radial nerve is compressed. To diagnosis radial tunnel syndrome, clinical examination is more important than paraclinic tests such as electrodiagnsic test and imaging studies. The exact site of the pain which can more specified by rule of nine test and weakness of the third finger and wrist extension are valuable physical exams to diagnosis. MRI studies my show muscle edema or atrophy along the distribution of the posterior interosseous nerve. Although non-surgical treatments such as rest, NSAIDs, injections and physiotherapy do not believe to have permanent relief, but it is justify undergoing them before surgery. Surgery could diminish pain and symptoms in 67 to 93 percents of patients completely. PMID:26213698

  20. Radial spoke proteins of Chlamydomonas flagella.

    PubMed

    Yang, Pinfen; Diener, Dennis R; Yang, Chun; Kohno, Takahiro; Pazour, Gregory J; Dienes, Jennifer M; Agrin, Nathan S; King, Stephen M; Sale, Winfield S; Kamiya, Ritsu; Rosenbaum, Joel L; Witman, George B

    2006-03-15

    The radial spoke is a ubiquitous component of '9+2' cilia and flagella, and plays an essential role in the control of dynein arm activity by relaying signals from the central pair of microtubules to the arms. The Chlamydomonas reinhardtii radial spoke contains at least 23 proteins, only 8 of which have been characterized at the molecular level. Here, we use mass spectrometry to identify 10 additional radial spoke proteins. Many of the newly identified proteins in the spoke stalk are predicted to contain domains associated with signal transduction, including Ca2+-, AKAP- and nucleotide-binding domains. This suggests that the spoke stalk is both a scaffold for signaling molecules and itself a transducer of signals. Moreover, in addition to the recently described HSP40 family member, a second spoke stalk protein is predicted to be a molecular chaperone, implying that there is a sophisticated mechanism for the assembly of this large complex. Among the 18 spoke proteins identified to date, at least 12 have apparent homologs in humans, indicating that the radial spoke has been conserved throughout evolution. The human genes encoding these proteins are candidates for causing primary ciliary dyskinesia, a severe inherited disease involving missing or defective axonemal structures, including the radial spokes. PMID:16507594

  1. Effect of the thermal environment on the efficiency of packed columns in supercritical fluid chromatography.

    PubMed

    Zauner, Jordan; Lusk, Ryan; Koski, Steven; Poe, Donald P

    2012-11-30

    When a packed column is operated at temperatures and pressures near the critical point in supercritical fluid chromatography, the thermal environment in which it is placed has a significant impact on retention and efficiency. We measured the retention factors, plate heights, and related parameters for elution of a test mixture of alkylbenzenes with 5% methanol/95% carbon dioxide mobile phase on a 250 mm 4.6 mm i.d. column packed with 5-micron Luna-C18 particles. Separations were performed at outlet pressures from 100 to 150 bar and a column oven temperature of 323K. For a bare column thermostated with convective air, significant efficiency losses were observed for outlet pressures equal to or less than 120 bar. These large efficiency losses are attributed to radial temperature gradients. Addition of foam insulation resulted in significant improvements in efficiency. Operating the column in still air using a commercially available column heater provided the best overall performance, with no measurable efficiency loss over the entire range of pressures studied. A reduced plate height of 1.88 was obtained at an optimum flow rate of 3.0 mL/min at 100 bar outlet pressure and with the temperature of the incoming mobile phase set approximately 2.3K above the temperature of the column oven. Retention time repeatability for all three thermal conditions was equal to or less than 0.5% RSD. These results demonstrate that it is possible to perform fast, efficient separations with excellent repeatability using SFC under near-critical conditions if the thermal environment is optimized to minimize the generation of radial temperature gradients. PMID:23107122

  2. The Usefulness of Proximal Radial Motor Conduction in Acute Compressive Radial Neuropathy

    PubMed Central

    Kim, Kun Hyun; Park, Kee-Duk; Chung, Pil-Wook; Moon, Heui-Soo; Kim, Yong Bum; Yoon, Won Tae

    2015-01-01

    Background and Purpose The objective of this study was to determine diagnostic and prognostic values of proximal radial motor conduction in acute compressive radial neuropathy. Methods Thirty-nine consecutive cases of acute compressive radial neuropathy with radial conduction studies-including stimulation at Erb's point-performed within 14 days from clinical onset were reviewed. The radial conduction data of 39 control subjects were used as reference data. Results Thirty-one men and eight women (age, 45.212.7 years, meanSD) were enrolled. All 33 patients in whom clinical follow-up data were available experienced complete recovery, with a recovery time of 46.834.3 days. Partial conduction block was found frequently (17 patients) on radial conduction studies. The decrease in the compound muscle action potential area between the arm and Erb's point was an independent predictor for recovery time. Conclusions Proximal radial motor conduction appears to be a useful method for the early detection and prediction of prognosis of acute compressive radial neuropathy. PMID:25851897

  3. Plasma signatures on radially resolved line emission

    NASA Astrophysics Data System (ADS)

    Hansen, S. B.; Jones, B.; Rochau, G. A.; Bailey, J. E.; Ampleford, D. J.; Jennings, C. A.; Coverdale, C. A.; Cuneo, M. E.; Maron, Y.; Fisher, V.; Bernshtam, V.; Starobinets, A.; Weingarten, L.

    2009-11-01

    In the last few years, various intriguing emission profiles have been observed in time-gated, radially resolved measurements of K-shell line emission from imploding and stagnating Z-pinch plasmas. The radially resolved lines have appeared as hollow or closed ovals whose extents in the spatial and (Doppler-shifted) wavelength dimensions record the plasma radius and velocity, respectively. Optically thick lines can lead to asymmetries in both spatial and wavelength dimensions, such as limb darkening and preferential absorption of velocity-matched wavelengths. We present the results of a comprehensive investigation of density, temperature, and velocity gradients and their effects on radially resolved emission lines, listing the combinations of plasma conditions that can give rise to signature emission features. Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  4. Manufacturing of Precision Forgings by Radial Forging

    SciTech Connect

    Wallner, S.; Harrer, O.; Buchmayr, B.; Hofer, F.

    2011-01-17

    Radial forging is a multi purpose incremental forging process using four tools on the same plane. It is widely used for the forming of tool steels, super alloys as well as titanium- and refractory metals. The range of application goes from reducing the diameters of shafts, tubes, stepped shafts and axels, as well as for creating internal profiles for tubes in Near-Net-Shape and Net-Shape quality. Based on actual development of a weight optimized transmission input shaft, the specific features of radial forging technology is demonstrated. Also a Finite Element Model for the simulation of the process is shown which leads to reduced pre-processing effort and reduced computing time compared to other published simulation methods for radial forging. The finite element model can be applied to quantify the effects of different forging strategies.

  5. Manufacturing of Precision Forgings by Radial Forging

    NASA Astrophysics Data System (ADS)

    Wallner, S.; Harrer, O.; Buchmayr, B.; Hofer, F.

    2011-01-01

    Radial forging is a multi purpose incremental forging process using four tools on the same plane. It is widely used for the forming of tool steels, super alloys as well as titanium- and refractory metals. The range of application goes from reducing the diameters of shafts, tubes, stepped shafts and axels, as well as for creating internal profiles for tubes in Near-Net-Shape and Net-Shape quality. Based on actual development of a weight optimized transmission input shaft, the specific features of radial forging technology is demonstrated. Also a Finite Element Model for the simulation of the process is shown which leads to reduced pre-processing effort and reduced computing time compared to other published simulation methods for radial forging. The finite element model can be applied to quantify the effects of different forging strategies.

  6. Dispersion-free radial transmission lines

    DOEpatents

    Caporaso, George J. (Livermore, CA); Nelson, Scott D. (Patterson, CA)

    2011-04-12

    A dispersion-free radial transmission line ("DFRTL") preferably for linear accelerators, having two plane conductors each with a central hole, and an electromagnetically permeable material ("EPM") between the two conductors and surrounding a channel connecting the two holes. At least one of the material parameters of relative magnetic permeability, relative dielectric permittivity, and axial width of the EPM is varied as a function of radius, so that the characteristic impedance of the DFRTL is held substantially constant, and pulse transmission therethrough is substantially dispersion-free. Preferably, the EPM is divided into concentric radial sections, with the varied material parameters held constant in each respective section but stepwise varied between sections as a step function of the radius. The radial widths of the concentric sections are selected so that pulse traversal time across each section is the same, and the varied material parameters of the concentric sections are selected to minimize traversal error.

  7. Application of radial-splitters for improved wide-angle diffuser performance in a blowdown tunnel

    NASA Technical Reports Server (NTRS)

    Rao, D. M.; Seshadri, S. N.

    1976-01-01

    Severe flow separation in the 15:1 area-ratio, 38 deg total angle conical diffuser preceding the settling-chamber of an intermittent blowdown wind tunnel was eliminated by the use of a novel radial-splitter arrangement. As a consequence, the operating life of settling-chamber screens was greatly extended and test-section flow steadiness improved, with no penalty in the tunnel running time.

  8. Note on radial correlation factors of atoms

    NASA Astrophysics Data System (ADS)

    Koga, Toshikatsu

    2014-11-01

    A peculiar property is reported for the pth order (2 ? p ? N) radial correlation factor of an N-electron atom (N ? 2). When the pth electron goes away from the nucleus, the correlation factor reduces, apart from the constant unity, to the ratio between the (p - 1)th order reduced radial densities of the (N - 1)- and N-electron atoms, where both atoms are considered to be in their non-degenerate ground states. The result implies that an electron annihilation function for the reduced densities is defined by a particular case of the correlation factor. A numerical illustration is given for a simple system.

  9. Aircraft radial-belted tire evaluation

    NASA Technical Reports Server (NTRS)

    Yager, Thomas J.; Stubbs, Sandy M.; Davis, Pamela A.

    1990-01-01

    An overview is given of the ongoing joint NASA/FAA/Industry Surface Traction And Radial Tire (START) Program being conducted at NASA Langley's Aircraft Landing Dynamics Facility (ALDF). The START Program involves tests using three different tire sizes to evaluate tire rolling resistance, braking, and cornering performance throughout the aircraft ground operational speed range for both dry and wet runway surfaces. Preliminary results from recent 40 x 14 size bias-ply, radial-belted, and H-type aircraft tire tests are discussed. The paper concludes with a summary of the current program status and planned ALDF test schedule.

  10. Precise Near-Infrared Radial Velocities

    NASA Astrophysics Data System (ADS)

    Plavchan, Peter; Gao, Peter; Gagne, Jonathan; Furlan, Elise; Brinkworth, Carolyn; Bottom, Michael; Tanner, Angelle; Anglada-Escude, Guillem; White, Russel; Davison, Cassy; Mills, Sean; Beichman, Chas; Johnson, John Asher; Ciardi, David; Wallace, Kent; Mennesson, Bertrand; Vasisht, Gautam; Prato, Lisa; Kane, Stephen; Crawford, Sam; Crawford, Tim; Sung, Keeyoon; Drouin, Brian; Lin, Sean; Leifer, Stephanie; Catanzarite, Joe; Henry, Todd; von Braun, Kaspar; Walp, Bernie; Geneser, Claire; Ogden, Nick; Stufflebeam, Andrew; Pohl, Garrett; Regan, Joe

    2015-11-01

    We present the results of two 2.3 ?m near-infrared (NIR) radial velocity (RV) surveys to detect exoplanets around 36 nearby and young M dwarfs. We use the CSHELL spectrograph (R ~ 46,000) at the NASA InfraRed Telescope Facility (IRTF), combined with an isotopic methane absorption gas cell for common optical path relative wavelength calibration. We have developed a sophisticated RV forward modeling code that accounts for fringing and other instrumental artifacts present in the spectra. With a spectral grasp of only 5 nm, we are able to reach long-term radial velocity dispersions of ~20-30 m s-1 on our survey targets.

  11. The radial velocity search for extrasolar planets

    NASA Technical Reports Server (NTRS)

    Mcmillan, Robert S.

    1991-01-01

    Radial velocity measurements are being made to search for planets orbiting stars other than the Sun. The reflex acceleration induced on stars by planets can be sensed by measuring the small, slow changes in the line-of-site velocities of stars. To detect these planetary perturbations, the data series must be made on a uniform instrumental scale for as long as it takes a planet to orbit its star. A spectrometer of extreme stability and unprecedented sensitivity to changes in stellar radial velocities was operated.

  12. Precise Near-Infrared Radial Velocities

    NASA Astrophysics Data System (ADS)

    Plavchan, Peter; Gao, Peter; Gagne, Jonathan; Furlan, Elise; Brinkworth, Carolyn; Bottom, Michael; Tanner, Angelle; Anglada-Escude, Guillem; White, Russel; Davison, Cassy; Mills, Sean; Beichman, Chas; Johnson, John Asher; Ciardi, David; Wallace, Kent; Mennesson, Bertrand; Vasisht, Gautam; Prato, Lisa; Kane, Stephen; Crawford, Sam; Crawford, Tim; Sung, Keeyoon; Drouin, Brian; Lin, Sean; Leifer, Stephanie; Catanzarite, Joe; Henry, Todd; von Braun, Kaspar; Walp, Bernie; Geneser, Claire; Ogden, Nick; Stufflebeam, Andrew; Pohl, Garrett; Regan, Joe

    2016-01-01

    We present the results of two 2.3 ?m near-infrared (NIR) radial velocity (RV) surveys to detect exoplanets around 36 nearby and young M dwarfs. We use the CSHELL spectrograph (R ~ 46,000) at the NASA InfraRed Telescope Facility (IRTF), combined with an isotopic methane absorption gas cell for common optical path relative wavelength calibration. We have developed a sophisticated RV forward modeling code that accounts for fringing and other instrumental artifacts present in the spectra. With a spectral grasp of only 5 nm, we are able to reach long-term radial velocity dispersions of ~20-30 m s-1 on our survey targets.

  13. Low NO{sub x} combustion of pulverized coal using the radially stratified flame core burner

    SciTech Connect

    Barta, L.E.; Lewis, P.F.; Beer, J.M.

    1999-07-01

    Results are presented of a theoretical-experimental study aimed at determining the characteristics of pulverized coal flames produced with the Low NO{sub x} Radially Stratified Flame Core (RSFC) Burner. Following earlier studies with this burner in which very low pollutant emissions were attained with natural gas and heavy fuel oil, the present investigation turned to the combustion of pulverized coal. In particular, the fulfillment of the conditions required for staged combustion, i.e., maintenance of a fuel-rich flame core at high temperature and for an extended period of time by the stratification of the flow, have been investigated. The criterion for radial stratification of the flow was theoretically developed from the equations of motion, by balancing the rate of generation of turbulence and the rate of turbulence damping; the latter being due to a combination of steep radial density gradients and swirling flow. The optimal radial stratification was obtained in forced vortex flow, when the radial profiles of the axial and tangential components of the air flow at the burner exit were adjusted to satisfy the condition along the flame front: 1 {partial{underscore}derivative}{bar {rho}}/{bar {rho}} {partial{underscore}derivative}r = P{sub T} ({alpha}/{beta}){sup 2} 1/r where {rho} is density, r is the radial distance of the flame front, P{sub T} is the turbulent Prandtl number, and {alpha} and {beta} are the first radial derivatives of the axial and the tangential velocity, respectively, evaluated at the radial distance r. A parametric combustion study carried out by burning a high volatile bituminous coal at a thermal input of 1.5 MW has shown that by setting a ratio {alpha}/{beta} = 0.76 at the burner, a stratified flame was created, and the NO{sub x} emission was reduced from an uncontrolled range of 700--900 ppm to 217 ppm. Further reduction to 70 ppm was achieved by external air staging. For this latter condition, however, the RSFC burner was operated to produce a well stirred, high temperature, fuel-rich flame with overfire air injected at some distance downstream of the burner. Both flame types were highly stable with 99.5% and 99.3% carbon conversion, respectively.

  14. Modeling of thermal processes in high pressure liquid chromatography II. Thermal heterogeneity at very high pressures

    SciTech Connect

    Kaczmarski, Krzysztof; Gritti, Fabrice; Guiochon, Georges A

    2009-01-01

    Advanced instruments for liquid chromatography enables the operation of columns packed with sub-2 {micro}m particles at the very high inlet pressures, up to 1000 bar, that are necessary to achieve the high column efficiency and the short analysis times that can be provided by the use of these columns. However, operating rather short columns at high mobile phase velocities, under high pressure gradients causes the production of a large amount of heat due to the viscous friction of the eluent percolating through the column bed. The evacuation of this heat causes the formation of significant axial and radial temperature gradients. Due to these thermal gradients, the retention factors of analytes and the mobile phase velocity are no longer constant throughout the column. The consequence of this heat production is a loss of column efficiency. We previously developed a model combining the heat and mass balance of the column, the equations of flow through porous media, and a linear isotherm model of the analyte. This model was solved and validated for conventional columns operated under moderate pressures. We report here on the results obtained when this model is applied to columns packed with very fine particles, operated under very high pressures. These results prove that our model accounts well for all the experimental results. The same column that elutes symmetrical, nearly Gaussian peaks at low flow rates, under relatively low pressure drops, provides strongly deformed, unsymmetrical peaks when operated at high flow rates, under high pressures, and under different thermal environments. The loss in column efficiency is particularly important when the column wall is kept at constant temperature, by immersing the column in a water bath.

  15. One-year results of cemented bipolar radial head prostheses for comminuted radial head fractures

    PubMed Central

    Laun, Reinhold; Wild, Michael; Hakimi, Mohssen

    2015-01-01

    Introduction: Comminuted radial head fractures (Mason type III) continue to pose a challenge to orthopedic surgeons. When internal fixation is not possible, radial head arthroplasty has been advocated as the treatment of choice. The purpose of this retrospective study was to evaluate clinical and radiological short-term results of patients with Mason type III radial head fractures treated with a cemented bipolar radial prosthesis. Methods: Twelve patients received cemented bipolar radial head hemiarthroplasty for comminuted radial head fractures. In all patients a CT scan was obtained prior to surgical treatment to assess all associated injuries. Postoperatively an early motion protocol was applied. All patients were evaluated clinically and radiologically at an average of 12.7 months. Results: According to the Mayo Modified Wrist Score, the Mayo Elbow Performance Score, the functional rating index of Broberg and Morrey, and the DASH Score good to excellent results were obtained. Grip strength and range of motion were almost at the level of the unaffected contralateral side. Patient satisfaction was high, no instability or signs of loosening of the implant, and only mild signs of osteoarthritis were seen. Conclusion: Overall good to excellent short-term results for primary arthroplasty for comminuted radial head fractures were observed. These encouraging results warrant the conduction of further studies with long-term follow-up and more cases to see if these short-term results can be maintained over time. PMID:26734534

  16. Swept Inducer Blades With Tandem Radial Slots

    NASA Technical Reports Server (NTRS)

    Meng, Sen Y.

    1995-01-01

    Slanted radial slots at tandem positions along approximate streamlines incorporated into swept inducer blades in turbopump, according to proposal. With suitable design, slots suppress low-frequency oscillations induced by cavitation, without causing excessive loss of inducer head. Slots cut into solid blades by wire electrical-discharge machining.

  17. JPC = ODD-- Radial Trajectories for Light Mesons

    NASA Astrophysics Data System (ADS)

    Dumanoglu, I.; Peaslee, D. C.

    2003-01-01

    Versification of the Veneziano model for light meson radial trajectories has found surprising constancy of slope for several different sequences of resonant states with JPC = even++. Efforts to extend this result to JPC = odd-- trajectories have been hampered by a comparative scarcity of data, but we present an early survey to seek similarities and differences with even++ resonances.

  18. Radial velocities in the globular cluster ? Centauri

    NASA Astrophysics Data System (ADS)

    Reijns, R. A.; Seitzer, P.; Arnold, R.; Freeman, K. C.; Ingerson, T.; van den Bosch, R. C. E.; van de Ven, G.; de Zeeuw, P. T.

    2006-01-01

    We have used the ARGUS multi-object spectrometer at the CTIO 4 m Blanco telescope to obtain 2756 radial velocity measurements for 1966 individual stars in the globular cluster ? Centauri brighter than blue photographic magnitude of about 16.5. Of these, 1589 stars are cluster members. A comparison with two independent radial velocity studies, carried out by Suntzeff & Kraft and by Mayor et al., demonstrates that the median error of our measurements is below 2 km s-1 for the stars brighter than B-magnitude 15, which constitute the bulk of the sample. The observed velocity dispersion decreases from about 15 km s-1 in the inner few arcmin to about 6 km s-1 at a radius of 25'. The cluster shows significant rotation, with a maximum amplitude of about 6 km s-1 in the radial zone between 6' and 10'. In a companion paper by van de Ven et al., we correct these radial velocities for the perspective rotation caused by the space motion of the cluster, and combine them with the internal proper motions of nearly 8000 cluster members measured by van Leeuwen et al., to construct a detailed dynamical model of ? Centauri and to measure its distance.

  19. Determining Enzyme Activity by Radial Diffusion

    ERIC Educational Resources Information Center

    Davis, Bill D.

    1977-01-01

    Discusses advantages of radial diffusion assay in determining presence of enzyme and/or rough approximation of amount of enzyme activities. Procedures are included for the preparation of starch-agar plates, and the application and determination of enzyme. Techniques using plant materials (homogenates, tissues, ungerminated embryos, and seedlings)…

  20. Radial velocities of Planetary Nebulae revisited

    NASA Astrophysics Data System (ADS)

    Vázquez, Roberto; Ayala, Sandra A.; Wendolyn Blanco Cárdenas, Mónica; Contreras, María E.; Gómez-Muñoz, Marco Antonio; Guillén, Pedro F.; Olguín, Lorenzo; Ramos-Larios, Gerardo; Sabin, Laurence; Zavala, Saúl A.

    2015-08-01

    We present a new determination of radial velocities of a sample of Galactic Planetary Nebulae (PNe) using a systematic method and the same instrumental setting: the long-slit high-dispersion Manchester Echelle Spectrograph (MES) on the 2.1-m telescope at the San Pedro Mártir Observatory (OAN-SPM; Mexico). This project was inspired by the work of Schneider et al. (1983, A&AS, 52, 399), which has been an important reference during the last decades. Radial velocities of gaseous nebulae can be obtained using the central wavelength of a Gaussian fit, even when there is an expansion velocity, as expected in PNe, but with not enough resolution to see a spectral line splitting. We have used the software SHAPE, a morpho-kinematic modeling and reconstruction tool for astrophysical objects (Steffen et al. 2011, IEEE Trans. Vis. Comput. Graphics, 17, 454), to prove that non-uniform density or brightness, on an expanding shell, can lead to mistaken conclusions about the radial velocity. To determine radial velocities, we only use the spectral data in which a spectral line-splitting is seen, avoiding thus the problem of the possible biased one-Gaussian fit. Cases when this method is not recommended are discussed.This project has been supported by grant PAPIIT-DGAPA-UNAM IN107914. MWB is in grateful receipt of a DGAPA-UNAM postdoctoral scholarship. MAG acknowledges CONACYT for his graduate scholarship.

  1. Geometric Derivation of Radial Acceleration Magnitude.

    ERIC Educational Resources Information Center

    Kraft, David W.; Motz, Lloyd

    1995-01-01

    Standard treatments of uniform circular motion generally employ a combination of geometric and kinematic arguments to obtain the magnitude of radial acceleration. Presents a novel approach to the geometric portion of the derivation that uses the property that vectors can be translated parallel to themselves. (JRH)

  2. Legal and malpractice implications of radial keratotomy.

    PubMed

    Scholles, J R

    1986-08-01

    Radial keratotomy has the potential to produce a new malpractice crisis for ophthalmology. Though the surgery is often successful in reducing myopia, there are a great many undesirable side effects. The endothelial cell loss frequently resulting from the procedure bodes long term caution. PMID:3745772

  3. Determining Enzyme Activity by Radial Diffusion

    ERIC Educational Resources Information Center

    Davis, Bill D.

    1977-01-01

    Discusses advantages of radial diffusion assay in determining presence of enzyme and/or rough approximation of amount of enzyme activities. Procedures are included for the preparation of starch-agar plates, and the application and determination of enzyme. Techniques using plant materials (homogenates, tissues, ungerminated embryos, and seedlings)

  4. Extended foil capacitor with radially spoked electrodes

    DOEpatents

    Foster, James C. (Indian Shores, FL)

    1990-01-01

    An extended foil capacitor has a conductive disk electrically connected in oncrushing contact to the extended foil. A conductive paste is placed through spaces between radial spokes on the disk to electrically and mechanically connect the extended foil to the disk.

  5. Geodesic acoustic modes in tokamak plasmas with a radial equilibrium electric field

    NASA Astrophysics Data System (ADS)

    Zhou, Deng

    2015-09-01

    The dispersion relation of geodesic acoustic modes in the tokamak plasma with an equilibrium radial electric field is derived and analyzed. Multiple branches of eigenmodes have been found, similar to the result given by the fluid model with a poloidal mass flow. Frequencies and damping rates of both the geodesic acoustic mode and the sound wave increase with respect to the strength of radial electric field, while the frequency and the damping rate of the lower frequency branch slightly decrease. Possible connection to the experimental observation is discussed.

  6. Lysozyme fractionation from egg white at pilot scale by means of tangential flow membrane adsorbers: Investigation of the flow conditions.

    PubMed

    Brand, Janina; Voigt, Katharina; Zochowski, Bianca; Kulozik, Ulrich

    2016-03-18

    The application of membrane adsorbers instead of classical packed bed columns for protein fractionation is still a growing field. In the case of egg white protein fractionation, the application of classical chromatography is additionally limited due to its high viscosity that impairs filtration. By using tangential flow membrane adsorbers as stationary phase this limiting factor can be left out, as they can be loaded with particle containing substrates. The flow conditions existing in tangential flow membrane adsorbers are not fully understood yet. Thus, the aim of the present study was to gain a deeper understanding of the transport mechanisms in tangential flow membrane adsorbers. It was found that loading in recirculation mode instead of single pass mode increased the binding capacity (0.39 vs. 0.52mgcm(-2)). Further, it was shown that either higher flow rates (0.39mgcm(-2) vs. 0.57mgcm(-2) at 1CVmin(-1) or 20CVmin(-1), respectively) or higher amounts of the target protein in the feed (0.24mgcm(-2) vs. 0.85mgcm(-2) for 2.5 or 39.0g lysozyme, respectively) led to more protein binding. These results show that, in contrast to radial flow or flat sheet membrane adsorbers, the transport in tangential flow membrane adsorbers is not purely based on convection, but on a mix of convection and diffusion. Additionally, investigations concerning the influence of fouling formation were performed that can lead to transport limitations. It was found that this impact is neglectable. It can be concluded that the usage of tangential flow membrane adsorbers is very recommendable for egg white protein fractionations, although the transport is partly diffusion-limited. PMID:26898148

  7. Experimental Characterization of Piezoelectric Radial Field Diaphragms for Fluidic Control

    NASA Technical Reports Server (NTRS)

    Bryant, R. G.; Kavli, S. E.; Thomas, R. A., Jr.; Darji, K. J.; Mossi, K. M.

    2004-01-01

    NASA has recently developed a new piezoelectric actuator, the Radial Field Diaphragm or RFD. This actuator uses a radially-directed electric field to generate concentric out-of-plane (Z-axis) motion that allows this packaged device to be used as a pump or valve diaphragm. In order to efficiently use this new active device, experimental determination of pressure, flow rate, mechanical work, power consumption and overall efficiency needs to be determined by actually building a pump. However, without an optimized pump design, it is difficult to assess the quality of the data, as these results are inherent to the actual pump. Hence, separate experiments must be conducted in order to generate independent results to help guide the design criteria and pump quality. This paper focuses on the experiments used to generate the RFD's operational parameters and then compares these results to the experimentally determined results of several types of ball pumps. Also discussed are how errors are inherently introduced into the experiments, the pump design, experimental hardware and their effects on the overall system efficiency.

  8. Forced responses on a radial turbine with nozzle guide vanes

    NASA Astrophysics Data System (ADS)

    Liu, Yixiong; Yang, Ce; Ma, Chaochen; Lao, DaZhong

    2014-04-01

    Radial turbines with nozzle guide vanes are widely used in various size turbochargers. However, due to the interferences with guide vanes, the blades of impellers are exposed to intense unsteady aerodynamic excitations, which cause blade vibrations and lead to high cycle failures (HCF). Moreover, the harmonic resonance in some frequency regions are unavoidable due to the wide operation conditions. Aiming to achieve a detail insight into vibration characteristics of radial flow turbine, a numerical method based on fluid structure interaction (FSI) is presented. Firstly, the unsteady aerodynamic loads are determined by computational fluid dynamics (CFD). And the fluctuating pressures are transformed from time domain to frequency domain by fast Fourier-transform (FFT). Then, the entire rotor model is adopted to analyze frequencies and mode shapes considering mistuning in finite element (FE) method. Meanwhile, harmonic analyses, applying the pressure fluctuation from CFD, are conducted to investigate the impeller vibration behavior and blade forced response in frequency domain. The prediction of the vibration dynamic stress shows acceptable agreement to the blade actual damage in consistent tendency.

  9. The Transverse Radial Diverging Initiation Behavior of PBX 9502

    NASA Astrophysics Data System (ADS)

    Salyer, Terry; Aslam, Tariq

    2015-06-01

    A series of experiments examining the transverse radial initiation behavior of PBX 9502 has been fielded in a geometric configuration of PBX 9502 acceptor annulus and PBX 9501 donor core. The experiments were specifically designed to examine diverging initiation from the core. For sufficient diameter, the cylindrical donor core initiates the acceptor annulus with behavior akin to typical corner turning with the expected dead zone features. Even though PBX 9501 is significantly more energetic than PBX 9502, the critical initiation diameter is greater than the critical failure diameter of PBX 9502. The behavior of this initiation threshold is studied along with the dynamics of the shock initiating layer between the two dissimilar explosives. Streak camera imaging is used to examine the wave dynamics at the periphery of the PBX 9502 acceptor annulus, and to take measurements of the initiating layer at the material interface for comparison to the analogous behavior in the layered slab geometry. Additionally, proton radiographic imaging is used to examine the complex internal initiation dynamics, and high fidelity reactive flow modeling is used to accurately predict the transverse radial initiation behavior in the geometry of the test.

  10. A Better Method for Filling Pasteur Pipet Chromatography Columns

    ERIC Educational Resources Information Center

    Ruekberg, Ben

    2006-01-01

    An alternative method for the preparation of Pasteur pipet chromatography columns is presented that allows the column to be filled with solvent without bubbles and allows greater control of fluid flow while the materials to be separated are added. Students are required to wear gloves and goggles and caution should be used while handling glass…

  11. A Better Method for Filling Pasteur Pipet Chromatography Columns

    ERIC Educational Resources Information Center

    Ruekberg, Ben

    2006-01-01

    An alternative method for the preparation of Pasteur pipet chromatography columns is presented that allows the column to be filled with solvent without bubbles and allows greater control of fluid flow while the materials to be separated are added. Students are required to wear gloves and goggles and caution should be used while handling glass

  12. Top-down identification and quantification of stable isotope labeled proteins from Aspergillus flavus using online nano-flow reversed-phase liquid chromatography coupled to a LTQ-FTICR mass spectrometer.

    PubMed

    Collier, Timothy S; Hawkridge, Adam M; Georgianna, D Ryan; Payne, Gary A; Muddiman, David C

    2008-07-01

    Online liquid chromatography-mass spectrometric (LC-MS) analysis of intact proteins (i.e., top-down proteomics) is a growing area of research in the mass spectrometry community. A major advantage of top-down MS characterization of proteins is that the information of the intact protein is retained over the vastly more common bottom-up approach that uses protease-generated peptides to search genomic databases for protein identification. Concurrent to the emergence of top-down MS characterization of proteins has been the development and implementation of the stable isotope labeling of amino acids in cell culture (SILAC) method for relative quantification of proteins by LC-MS. Herein we describe the qualitative and quantitative top-down characterization of proteins derived from SILAC-labeled Aspergillus flavus using nanoflow reversed-phase liquid chromatography directly coupled to a linear ion trap Fourier transform ion cyclotron resonance mass spectrometer (nLC-LTQ-FTICR-MS). A. flavus is a toxic filamentous fungus that significantly impacts the agricultural economy and human health. SILAC labeling improved the confidence of protein identification, and we observed 1318 unique protein masses corresponding to 659 SILAC pairs, of which 22 were confidently identified. However, we have observed some limiting issues with regard to protein quantification using top-down MS/MS analyses of SILAC-labeled proteins. The role of SILAC labeling in the presence of competing endogenously produced amino acid residues and its impact on quantification of intact species are discussed in detail. PMID:18512951

  13. Development of a thermal and structural analysis procedure for cooled radial turbines

    NASA Technical Reports Server (NTRS)

    Kumar, Ganesh N.; Deanna, Russell G.

    1988-01-01

    A procedure for computing the rotor temperature and stress distributions in a cooled radial turbine is considered. Existing codes for modeling the external mainstream flow and the internal cooling flow are used to compute boundary conditions for the heat transfer and stress analyses. An inviscid, quasi three-dimensional code computes the external free stream velocity. The external velocity is then used in a boundary layer analysis to compute the external heat transfer coefficients. Coolant temperatures are computed by a viscous one-dimensional internal flow code for the momentum and energy equation. These boundary conditions are input to a three-dimensional heat conduction code for calculation of rotor temperatures. The rotor stress distribution may be determined for the given thermal, pressure and centrifugal loading. The procedure is applied to a cooled radial turbine which will be tested at the NASA Lewis Research Center. Representative results from this case are included.

  14. Development of a thermal and structural analysis procedure for cooled radial turbines

    NASA Technical Reports Server (NTRS)

    Kumar, Ganesh N.; Deanna, Russell G.

    1988-01-01

    A procedure for computing the rotor temperature and stress distributions in a cooled radial turbine are considered. Existing codes for modeling the external mainstream flow and the internal cooling flow are used to compute boundary conditions for the heat transfer and stress analysis. The inviscid, quasi three dimensional code computes the external free stream velocity. The external velocity is then used in a boundary layer analysis to compute the external heat transfer coefficients. Coolant temperatures are computed by a viscous three dimensional internal flow cade for the momentum and energy equation. These boundary conditions are input to a three dimensional heat conduction code for the calculation of rotor temperatures. The rotor stress distribution may be determined for the given thermal, pressure and centrifugal loading. The procedure is applied to a cooled radial turbine which will be tested at the NASA Lewis Research Center. Representative results are given.

  15. The Stationary Condensation and Radial Outflow of a Liquid Film on a Horizontal Disk

    NASA Technical Reports Server (NTRS)

    Bolshinskiy, Leonid; Frenkel, Alexander

    2008-01-01

    The application of capillary screen liquid acquisition devices to space-based cryogenic propulsion systems is expected to necessitate thermodynamic conditioning in order to stabilize surface tension retention characteristics. The present results have been obtained in the framework of the research of low gravity condensation-flow processes for conditioning cryogenic liquid acquisition devices. The following system is studied: On the top of a subcooled horizontal disk, a liquid film condenses from the ambient saturated vapor. The liquid is forcedly removed at the disk edge, and there is an outward radial flow of the film. Stationary regimes of the flow are uncovered such that (i) the gravity is negligible, being eclipsed by the capillary forces; (ii) the film thickness is everywhere much smaller than the disk radius; and (iii) the slow-flow lubrication approximation is valid. A nonlinear differential equation for the film thickness as a function of the radial coordinate is obtained. The (two-dimensional) fields of velocities, temperature and pressure in the film are explicitly determined by the radial profile of its thickness. The equilibrium is controlled by two parameters: (i) the vapor-disk difference of temperatures and (ii) the liquid exhaust rate. For the flow regimes with a nearly uniform film thickness, the governing equation linearizes, and the film interface is analytically predicted to have a concave-up quartic parabola profile. Thus, perhaps counter-intuitively, the liquid film is thicker at the edge and thinner at the center of the disk.

  16. Assay for dihydroorotase using high-performance liquid chromatography with radioactivity detection

    SciTech Connect

    Mehdi, S.; Wiseman, J.S.

    1989-01-01

    An assay for measuring dihydroorotase activity was devised. Radiolabeled substrate and product were separated by high-performance liquid chromatography using a reverse-phase column with ion-pairing, and the radioactivity was quantitated by flow detection.

  17. Radial gas motions in The H I Nearby Galaxy Survey (THINGS)

    NASA Astrophysics Data System (ADS)

    Schmidt, Tobias M.; Bigiel, Frank; Klessen, Ralf S.; de Blok, W. J. G.

    2016-04-01

    The study of 21 cm line observations of atomic hydrogen allows detailed insight into the kinematics of spiral galaxies. We use sensitive high-resolution Very Large Array data from The H I Nearby Galaxy Survey (THINGS) to search for radial gas flows primarily in the outer parts (up to 3 × r25) of 10 nearby spiral galaxies. Inflows are expected to replenish the gas reservoir and fuel star formation under the assumption that galaxies evolve approximately in steady state. We carry out a detailed investigation of existing tilted ring fitting schemes and discover systematics that can hamper their ability to detect signatures of radial flows. We develop a new Fourier decomposition scheme that fits for rotational and radial velocities and simultaneously determines position angle and inclination as a function of radius. Using synthetic velocity fields we show that our novel fitting scheme is less prone to such systematic errors and that it is well suited to detect radial inflows in discs. We apply our fitting scheme to 10 THINGS galaxies and find clear indications of, at least partly previously unidentified, radial gas flows, in particular for NGC 2403 and NGC 3198 and to a lesser degree for NGC 7331, NGC 2903 and NGC 6946. The mass flow rates are of the same order but usually larger than the star formation rates. At least for these galaxies a scenario in which continuous mass accretion feeds star formation seems plausible. The other galaxies show a more complicated picture with either no clear inflow, outward motions or complex kinematic signatures.

  18. An Undergraduate Column Chromatography Experiment.

    ERIC Educational Resources Information Center

    Danot, M.; And Others

    1984-01-01

    Background information, list of materials needed, and procedures used are provided for an experiment designed to introduce undergraduate students to the theoretical and technical aspects of column chromatography. The experiment can also be shortened to serve as a demonstration of the column chromatography technique. (JN)

  19. Multiplex gas chromatography

    NASA Technical Reports Server (NTRS)

    Valentin, Jose R.

    1990-01-01

    The principles of the multiplex gas chromatography (GC) technique, which is a possible candidate for chemical analysis of planetary atmospheres, are discussed. Particular attention is given to the chemical modulators developed by present investigators for multiplex GC, namely, the thermal-desorption, thermal-decomposition, and catalytic modulators, as well as to mechanical modulators. The basic technique of multiplex GC using chemical modulators and a mechanical modulator is demonstrated. It is shown that, with the chemical modulators, only one gas stream consisting of the carrier in combination with the components is being analyzed, resulting in a simplified instrument that requires relatively few consumables. The mechanical modulator demonstrated a direct application of multiplex GC for the analysis of gases in atmosphere of Titan at very low pressures.

  20. Pressurized continuous chromatography

    SciTech Connect

    Canon, R.M.; Begovich, J.M.; Sisson, W.G.

    1980-04-01

    A pressurized continuous annular chromatograph has been developed for preparative separations. This device utilizes a slowly rotating annular bed of sorbent material, fixed multiple feed points, and fixed withdrawal locations. Most of our investigations have been performed with a 28-cm-diam column, but a larger model is being designed and constructed. The separation of copper, nickel, and cobalt components from a carbonate solution has been studied in detail. This solution simulates the leach liquor from the Caron process for recovering nickel and cobalt from laterite ores. Use of continuous gradient elution has been demonstrated. Recent studies have investigated several separations, including that of zirconium and hafnium (necessary for the production of zirconium for use in nuclear reactors), on a preparative scale. This system, because of its continuous feed and product withdrawal, its adaptability to large-scale operations, and its ability to separate many components, is expected to make chromatography a more competitive process in the industrial sector.

  1. Continuous-Flow Centrifugal Separator

    NASA Technical Reports Server (NTRS)

    Waldron, Robert D.

    1988-01-01

    Apparatus combines principles of centrifugal and cyclone separators to control movement of solid or liquid particles suspended in flowing gas. Spinning disk contains radial channels, width varys as function of distance from center. Gas flows from outer ring around disk toward center. Particles in gas collected at periphery, center or both.

  2. Compact bypass-flow filter

    NASA Technical Reports Server (NTRS)

    Swift, W. G.; Ulanovsky, J. M.

    1979-01-01

    Annular filter consisting of stacked rings separates particulates from bypass fluid passing through it in radial direction without slowing down main flow across unimpeded flow of fluid through its center. Applications include fluidized bed reactors, equipment for catalyst operations, and water purification.

  3. New Research on the Cowling and Cooling of Radial Engines

    NASA Technical Reports Server (NTRS)

    Molloy, Richard C.; Brewster, James H., III

    1943-01-01

    An extensive series of wind-tunnel tests on a half-scale conventional, nacelle model were made by the United Aircraft Corporation to determine and correlate the effects of many variables on cooling air flow and nacelle drag. The primary investigation was concerned with the reaction of these factors to varying conditions ahead of, across, and behind the engine. In the light of this investigation, common misconceptions and factors which are frequently overlooked in the cooling and cowling of radial engines are considered in some detail. Data are presented to support certain design recommendations and conclusions which should lead toward the improvement of present engine installations. Several charts are included to facilitate the estimation of cooling drag, available cooling pressure, and cowl exit area.

  4. Cooled variable-area radial turbine technology program

    NASA Technical Reports Server (NTRS)

    Large, G. D.; Meyer, L. J.

    1982-01-01

    The objective of this study was a conceptual evaluation and design analyses of a cooled variable-area radial turbine capable of maintaining nearly constant high efficiency when operated at a constant speed and pressure ratio over a range of flows corresponding to 50- to 100-percent maximum engine power. The results showed that a 1589K (2400 F) turbine was feasible that would satisfy a 4000-hour duty cycle life goal. The final design feasibility is based on 1988 material technology goals. A peak aerodynamic stage total efficiency of 0.88 was predicted at 100 percent power. Two candidate stators were identified: an articulated trailing-edge and a locally movable sidewall. Both concepts must be experimentally evaluated to determine the optimum configuration. A follow-on test program is proposed for this evaluation.

  5. Continuous Spore Disruption Using Radially Focused, High-Frequency Ultrasound

    SciTech Connect

    Chandler, Darrell P.; Brown, Jeremy D.; Bruckner-Lea, Cynthia J. ); Olson, Lydia; Posakony, Gerald J. ); Stults, Jennie R.; Valentine, Nancy B. ); Bond, Leonard J. )

    2000-12-01

    ABSTRACT-We report on the development of a novel, continuous-flow, radially focused ultrasonic disruptor capable of lysing Bacillus spores in the absence of added chemical denaturants, enzymes, or microparticles. Greater than 99% disruption was achieved for Bacillus globigii spores and Escherichia coli and Bacillus subtilis vegetative cells with sample residence times of 62, 12, and 12 s, respectively. Microscopic and SEM images indicated that at equivalent power levels, the incidence of cell death or loss of viability typically exceeded the efficiency of (visible) cell lysis. However, semiquantitative PCR showed up to a 1000-fold increase in intracellular DNA availability from ultrasonically disrupted spores, and liberated DNA was intact and available for subsequent detection.

  6. Radial head prosthesis after radial head and neck fractures - current literature and quality of evidence.

    PubMed

    Zwingmann, J; Bode, G; Hammer, T; Südkamp, N P; Strohm, P C

    2015-01-01

    Due to the elbow joint's complex functional anatomy, the multifragmentary nature of many fractures and concomitant destabilizing associated injuries, dislocated fractures of the radial head and neck still present a serious challenge for the orthopedic surgeon. Thorough knowledge of the elbow's anatomy and biomechanics is essential to analyze and understand the injury and plan its treatment. The aim of a differentiated therapy approach is to restore the joint's anatomy and kinetics, stable and painless joint function, and to avoid or at least delay posttraumatic joint changes. The degree of dislocation, stability of fragments, size and number of fractured joint surfaces and associated bony and ligamentous injuries (and the instability they incur) must be addressed in the therapy regimen. There are various treatment options depending on the injury's classification, i.e. a Mason I fracture is treated conservatively, while more severe injuries may require osteosynthesis and endoprosthesis. There is a lack of clear therapy recommendations based on solid evidence regarding Mason classification types III-IV. In particular expert opinions diverge and study results are inconsistent. Especially the value of radial head arthroplasty is still hotly debated. Key words: radial head fracture, radial head prosthesis, radial neck fracture, Mason classification, radial head arthroplasty, elbow injury. PMID:26317287

  7. Effect of radial inflow on vortex intensification and its application to wind vortex generators

    NASA Astrophysics Data System (ADS)

    Ide, H.

    1982-01-01

    A wind vortex turbine called a tornado-type wind generator system was studied both theoretically and experimentally to understand the basic nature of a vortex flow and to improve the power efficiencies of the system. Analytical solutions were obtained from the Navier-Stokes equations for the velocity distributions along the radial distance. The result demonstrates the important nature of a vortex structure that, in order to intensify a vortex inside the tower, radial inflow must be provided from the side walls. The contribution of this experimental work was to furnish the radial inflow by utilizing the dynamic head of incoming wind. Extracting wind energy by creating and maintaining an extremely low pressure region of an intensified vortex at the turbine exit through viscous pumping is an improvement for wind machines and consequently is a cost effective procedure.

  8. Experimental Evaluation of a Cooled Radial-inflow Turbine

    NASA Technical Reports Server (NTRS)

    Tirres, Lizet; Dicicco, L. Danielle; Nowlin, Brent C.

    1993-01-01

    Two 14.4 inch tip diameter rotors were installed and tested in the Small Engines Component Turbine Facility (SECTF) at NASA Lewis Research Center. The rotors, a solid and a cooled version of a radial-inflow turbine, were tested with a 15 vane stat or over a set of rotational speeds ranging from 80 to 120 percent design speed (17,500 to 21,500 rpm). The total-to-total stage pressure ratios ranged from 2.5 to 5.5. The data obtained at the equivalent conditions using the solid version of the rotor are presented with the cooled rotor data. A Reynolds number of 381,000 was maintained for both rotors, whose stages had a design mass flow of 4.0 Ibm/sec, a design work level of 59.61 Btu/lbm, and a design efficiency of 87 percent. The results include mass flow data, turbine torque, turbine exit flow angles, stage efficiency, and rotor inlet and exit surveys.

  9. SpicyNodes Radial Map Engine

    NASA Astrophysics Data System (ADS)

    Douma, M.; Ligierko, G.; Angelov, I.

    2008-10-01

    The need for information has increased exponentially over the past decades. The current systems for constructing, exploring, classifying, organizing, and searching information face the growing challenge of enabling their users to operate efficiently and intuitively in knowledge-heavy environments. This paper presents SpicyNodes, an advanced user interface for difficult interaction contexts. It is based on an underlying structure known as a radial map, which allows users to manipulate and interact in a natural manner with entities called nodes. This technology overcomes certain limitations of existing solutions and solves the problem of browsing complex sets of linked information. SpicyNodes is also an organic system that projects users into a living space, stimulating exploratory behavior and fostering creative thought. Our interactive radial layout is used for educational purposes and has the potential for numerous other applications.

  10. Radial inlet guide vanes for a combustor

    DOEpatents

    Zuo, Baifang; Simons, Derrick; York, William; Ziminsky, Willy S

    2013-02-12

    A combustor may include an interior flow path therethrough, a number of fuel nozzles in communication with the interior flow path, and an inlet guide vane system positioned about the interior flow path to create a swirled flow therein. The inlet guide vane system may include a number of windows positioned circumferentially around the fuel nozzles. The inlet guide vane system may also include a number of inlet guide vanes positioned circumferentially around the fuel nozzles and adjacent to the windows to create a swirled flow within the interior flow path.

  11. Radial rib antenna surface deviation analysis program

    NASA Technical Reports Server (NTRS)

    Coyner, J. V., Jr.

    1971-01-01

    A digital computer program was developed which analyzes any radial rib antenna with ribs radiating from a central hub. The program has the capability for calculating the antenna surface contour (reversed pillowing effect), the optimum rib shape for minimizing the rms surface error, and the actual rms surface error. Rib deflection due to mesh tension and catenary cable tension can also be compensated for, and the pattern from which the mesh gores are cut can be determined.

  12. Diurnal and seasonal variability in radial distribution of sap flux density: Implications for estimating stand transpiration.

    PubMed

    Fiora, Alessandro; Cescatti, Alessandro

    2006-09-01

    Daily and seasonal patterns in radial distribution of sap flux density were monitored in six trees differing in social position in a mixed coniferous stand dominated by silver fir (Abies alba Miller) and Norway spruce (Picea abies (L.) Karst) in the Alps of northeastern Italy. Radial distribution of sap flux was measured with arrays of 1-cm-long Granier probes. The radial profiles were either Gaussian or decreased monotonically toward the tree center, and seemed to be related to social position and crown distribution of the trees. The ratio between sap flux estimated with the most external sensor and the mean flux, weighted with the corresponding annulus areas, was used as a correction factor (CF) to express diurnal and seasonal radial variation in sap flow. During sunny days, the diurnal radial profile of sap flux changed with time and accumulated photosynthetic active radiation (PAR), with an increasing contribution of sap flux in the inner sapwood during the day. Seasonally, the contribution of sap flux in the inner xylem increased with daily cumulative PAR and the variation of CF was proportional to the tree diameter, ranging from 29% for suppressed trees up to 300% for dominant trees. Two models were developed, relating CF with PAR and tree diameter at breast height (DBH), to correct daily and seasonal estimates of whole-tree and stand sap flow obtained by assuming uniform sap flux density over the sapwood. If the variability in the radial profile of sap flux density was not accounted for, total stand transpiration would be overestimated by 32% during sunny days and 40% for the entire season. PMID:16740497

  13. Study of the Effect of Radial Electric Fields on Electrostatic Turbulence

    NASA Astrophysics Data System (ADS)

    Lehmer, Ronald Derrick

    The radial electric field and the shear in the field have been suggested to be likely candidates for controlling particle and heat transport changes in tokamak H-mode discharges. Using improved probe diagnostics and analysis techniques, the radial profiles of the density and potential are measured in PISCES-A, a linear reflex arc discharge simulating tokamak edge plasma conditions. In addition, the fluctuations in these quantities and the fluctuation-induced cross field particle transport are also measured with probes. The radial potential profile is modified by biasing ring electrodes outside of a limiting aperture radius, and the slope of the density profile is seen to increase when the inward radial electric field is increased. The level and nature of the fluctuations in the plasma also change when the radial electric field profile is modified, suggesting that the variation in the density profiles is not driven by classical mobility and diffusion effects. Single shear layer (SSL) and double shear layers (DSL) in the radial electric field and poloidal plasma flow are observed. Double shear layers in the electric field are observed to coincide with reductions in radial transport, but only when the width of layer is larger than the ion Larmor radius. Confinement in DSL cases also will vary with the strength of the electric field. Finally, theoretical predictions based upon data from PISCES-A suggests that a collisionless Simon-Hoh instability is excited due finite Larmor radius effects on the ions and that the Kelvin-Helmholtz instability is actually suppressed in double shear layers.

  14. Exploration of overloaded cation exchange chromatography for monoclonal antibody purification.

    PubMed

    Liu, Hui F; McCooey, Beth; Duarte, Tiago; Myers, Deanna E; Hudson, Terry; Amanullah, Ashraf; van Reis, Robert; Kelley, Brian D

    2011-09-28

    Cation exchange chromatography using conventional resins, having either diffusive or perfusive flow paths, operated in bind-elute mode has been commonly employed in monoclonal antibody (MAb) purification processes. In this study, the performance of diffusive and perfusive cation exchange resins (SP-Sepharose FF (SPSFF) and Poros 50HS) and a convective cation exchange membrane (Mustang S) and monolith (SO(3) Monolith) were compared. All matrices were utilized in an isocratic state under typical binding conditions with an antibody load of up to 1000 g/L of chromatographic matrix. The dynamic binding capacity of the cation exchange resins is typically below 100 g/L resin, so they were loaded beyond the point of anticipated MAb break through. All of the matrices performed similarly in that they effectively retained host cell protein and DNA during the loading and wash steps, while antibody flowed through each matrix after its dynamic binding capacity was reached. The matrices differed, though, in that conventional diffusive and perfusive chromatographic resins (SPSFF and Poros 50HS) demonstrated a higher binding capacity for high molecular weight species (HMW) than convective flow matrices (membrane and monolith); Poros 50HS displayed the highest HMW binding capacity. Further exploration of the conventional chromatographic resins in an isocratic overloaded mode demonstrated that the impurity binding capacity was well maintained on Poros 50HS, but not on SPSFF, when the operating flow rate was as high as 36 column volumes per hour. Host cell protein and HMW removal by Poros 50HS was affected by altering the loading conductivity. A higher percentage of host cell protein removal was achieved at a low conductivity of 3 mS/cm. HMW binding capacity was optimized at 5 mS/cm. Our data from runs on Poros 50HS resin also showed that leached protein A and cell culture additive such as gentamicin were able to be removed under the isocratic overloaded condition. Lastly, a MAb purification process employing protein A affinity chromatography, isocratic overloaded cation exchange chromatography using Poros 50HS and anion exchange chromatography using QSFF in flow through mode was compared with the MAb's commercial manufacturing process, which consisted of protein A affinity chromatography, cation exchange chromatography using SPSFF in bind-elute mode and anion exchange chromatography using QSFF in flow through mode. Comparable step yield and impurity clearance were obtained by the two processes. PMID:21871630

  15. Development of a Radial Deconsolidation Method

    SciTech Connect

    Helmreich, Grant W.; Montgomery, Fred C.; Hunn, John D.

    2015-12-01

    A series of experiments have been initiated to determine the retention or mobility of fission products* in AGR fuel compacts [Petti, et al. 2010]. This information is needed to refine fission product transport models. The AGR-3/4 irradiation test involved half-inch-long compacts that each contained twenty designed-to-fail (DTF) particles, with 20-μm thick carbon-coated kernels whose coatings were deliberately fabricated such that they would crack under irradiation, providing a known source of post-irradiation isotopes. The DTF particles in these compacts were axially distributed along the compact centerline so that the diffusion of fission products released from the DTF kernels would be radially symmetric [Hunn, et al. 2012; Hunn et al. 2011; Kercher, et al. 2011; Hunn, et al. 2007]. Compacts containing DTF particles were irradiated at Idaho National Laboratory (INL) at the Advanced Test Reactor (ATR) [Collin, 2015]. Analysis of the diffusion of these various post-irradiation isotopes through the compact requires a method to radially deconsolidate the compacts so that nested-annular volumes may be analyzed for post-irradiation isotope inventory in the compact matrix, TRISO outer pyrolytic carbon (OPyC), and DTF kernels. An effective radial deconsolidation method and apparatus appropriate to this application has been developed and parametrically characterized.

  16. Operation and Improvement of Liquid Nitrogen Pumps with Radial High- Temperature Superconductor Bearings

    NASA Astrophysics Data System (ADS)

    Lin, Q. X.; Jiang, D. H.; Deng, Z. G.; Ma, G. T.; Zheng, J.; Wang, W. J.; Shin, D. I.; Gu, X.; Lin, N.; Shao, M. L.

    2015-09-01

    This paper reviews the advantages of replacing the mechanical bearings of low-temperature pumps by radial high- temperature superconductor (HTS) bearings. Radial HTS bearings have the advantage of being non-abrasive, so that the working life is increased significantly. In this article, two types of liquid nitrogen pump with radial HTS bearings are proposed. To reduce heat leakage, one pump uses a permanent magnet (PM) coupling and the other uses a long hollow pipe coupling. Successful stable operation of these two pumps means that radial HTS bearings have the potential to be applied in liquid nitrogen pumps. Test results show that the flow rate is influenced mainly by rotational speed but not by the coupling component. Further designs of the two types of pump for practical applications are described, and their characteristics are analyzed: the pump with a PM coupling has lower heat leakage, whereas the pump with a long hollow pipe coupling can solve the force creep problem of the HTS bearing. The design of the pump with a long hollow pipe coupling is based on the pump that is already in practical use, and therefore has greater feasibility for practical applications. Finally, improvements of the liquid nitrogen pump by improving the structure of the pump and the performance of the radial HTS bearing are discussed.

  17. Structural radial heterogeneity of a silica-based wide-bore monolithic column

    SciTech Connect

    Mriziq, Khaled S; Guiochon, Georges A

    2008-01-01

    The radial distribution of the main characteristics (elution time and standard deviation) of the elution profiles of a flat injected band recorded at the exit of a monolithic column were determined. These distributions provide the radial distributions of the average mobile phase velocity, the elution time and the maximum height of the peak of an analyte, the column efficiency and the analyte concentration. The band profiles were measured at the exit of a 10-mm i.d., 100-mm long silica-based monolithic column. An on-column local electrochemical amperometric detector allowed the recording of the elution profiles at different spatial positions throughout the column cross-section. The local spatial distribution of the mobile phase velocity does not follow a piston-flow behavior but exhibits radial heterogeneity. The local efficiency near the wall is lower than that near the column center. The radial distribution of the maximum concentration of the peaks varies throughout the column exit section, partially due to the radial variations of the column efficiency. These results might explain the rather large value of the A term of the Van Deemter or the Knox equations reported previously for monolithic columns.

  18. Hydraulic analysis of a radial collector well for riverbank filtration near Nakdong River, South Korea

    NASA Astrophysics Data System (ADS)

    Lee, Eunhee; Hyun, Yunjung; Lee, Kang-Kun; Shin, Jiyoun

    2012-05-01

    A radial collector well is used for the extraction of a large amount of groundwater without causing a deep drawdown at the well's center, and it is appropriate for the supply of municipal water through riverbank filtration (RBF). Flow path changes caused by water extraction through a radial collector well were simulated to estimate the amount of river water induction at a RBF site associated with Nakdong River in South Korea. The structure of the screened horizontal arms of a radial collector well was examined with respect to effective riverbank filtration. The relative ratio of the river water induced to the radial collector well compared to the total groundwater extraction was estimated to be 27-52%. The amount of induced river water varies with the distance of a horizontal arm from the river, indicating that the location and structure of the collector well is significant for RBF. In all simulation cases, the maximum drawdown of the groundwater level near the collector well was 2.1 m, which is not significant considering the substantial pumping rate at the study site. It was concluded that RBF radial collector wells can be used at the study site for a sustainable water supply.

  19. Aerodynamically induced radial forces in a centrifugal gas compressor. Part 1: Experimental measurement

    SciTech Connect

    Moore, J.J.; Flathers, M.B.

    1998-04-01

    Net radial loading arising from asymmetric pressure fields in the volutes of centrifugal pumps during off-design operation is well known and has been studied extensively. In order to achieve a marked improvement in overall efficiency in centrifugal gas compressors, vaneless volute diffusers are matched to specific impellers to yield improved performance over a wide application envelope. As observed in centrifugal pumps, nonuniform pressure distributions that develop during operation above and below the design flow create static radial loads on the rotor. In order to characterize these radial forces, a novel experimental measurement and post-processing technique is employed that yields both the magnitude and direction of the load by measuring the shaft centerline locus in the tilt-pad bearings. The method is applicable to any turbomachinery operating on fluid film radial bearings equipped with proximity probes. The forces are found to be a maximum near surge and increase with higher pressures and speeds. The results are nondimensionalized, allowing the radial loading for different operating conditions to be predicted.

  20. The second five years of sequential injection chromatography: significant developments in the technology and methodologies.

    PubMed

    Idris, Abubakr M

    2014-01-01

    Sequential injection chromatography was proposed in 2003 to perform a simple, rapid, reagent-saving, environmentally benign, on-site, and instrumentally inexpensive separation procedure. Sequential injection chromatography is a version of sequential injection analysis, which is the second generation in the family of flow injection techniques. Despite its advantages over high-performance liquid chromatography, sequential injection chromatography has confronted some challenges. Furthermore, the applications of sequential injection chromatography in its first five years are almost all limited to pharmaceutical analysis. Interestingly, in its second five years, various developments in sequential injection chromatography technology were achieved. The developments have enhanced the efficiency of sequential injection chromatography and hence its applications have extended to biological, food, and environmental analyses. The main objectives of this review are to examine recent developments (2008-2013) in sequential injection chromatography and to describe how these developments improve the efficiency of the technology. The sequential injection chromatography methodologies reported during that period are also discussed along with controlling conditions and analytical results. The review also describes the principles, instrumentation, and procedure behind sequential injection chromatography. PMID:25391562