Science.gov

Sample records for radial flow chromatography

  1. Are axial and radial flow chromatography different?

    PubMed

    Besselink, Tamara; van der Padt, Albert; Janssen, Anja E M; Boom, Remko M

    2013-01-04

    Radial flow chromatography can be a solution for scaling up a packed bed chromatographic process to larger processing volumes. In this study we compared axial and radial flow affinity chromatography both experimentally and theoretically. We used an axial flow column and a miniaturized radial flow column with a ratio of 1.8 between outer and inner surface area, both with a bed height of 5 cm. The columns were packed with affinity resin to adsorb BSA. The average velocity in the columns was set equal. No difference in performance between the two columns could be observed. To gain more insight into the design of a radial flow column, the velocity profile and resin distribution in the radial flow column were calculated. Using mathematical models we found that the breakthrough performance of radial flow chromatography is very similar to axial flow when the ratio between outer and inner radius of the radial flow column is around 2. When this ratio is increased, differences become more apparent, but remain small. However, the ratio does have a significant influence on the velocity profile inside the resin bed, which directly influences the pressure drop and potentially resin compression, especially at higher values for this ratio. The choice between axial and radial flow will be based on cost price, footprint and packing characteristics. For small-scale processes, axial flow chromatography is probably the best choice, for resin volumes of at least several tens of litres, radial flow chromatography may be preferable.

  2. Efficient purification of antiproliferative polysaccharides from Hypsizigus marmoreus with radial flow chromatography.

    PubMed

    Yan, Pei-Sheng; Cao, Li-Xin; Zhang, Bing-Zhao

    2014-01-01

    The increasing commercial significance of natural polysaccharides for use in medicinal products is stimulating the development of efficient and easy scale-up techniques for polysaccharide purification. In this research, the crude polysaccharides from submerged cultivation broth of Hypsizigus marmoreus were purified using radial flow chromatography (RFC), and the antiproliferative activity of the purified fractions was evaluated in vitro. DEAE Sepharose CL-6B was selected to be packed in the RFC column based on its good resolution, physical stability, and low cost. Compared with axial flow chromatography (AFC), an efficient chromatographic process with significantly less time and buffer consumption but yielding higher polysaccharide recovery and resolution was established in RFC, which could clearly purify the crude polysaccharides into different fractions. An acceptable linear scale-up effect of RFC from 100 to 500 mL was successfully achieved without loss of resolution and enhancement of time consumption. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays in cell cultures indicated that the purified polysaccharide fractions possess moderate antiproliferative activities in three different human cancer cell lines, but have significantly lower cytotoxicity in normal human cell lines in vitro. Among the polysaccharide fractions, the main purified acidic fraction W-I could be considered as a novel potential antitumor agent candidate for several tumors, especially for human alveolar epithelial tumors. This research confirmed for the first time that RFC would be a new fast and efficient tool for purification of polysaccharides into different fractions, both at laboratory and commercial scales.

  3. Effect of geometry and scale for axial and radial flow membrane chromatography-Experimental study of bovin serum albumin adsorption.

    PubMed

    Teepakorn, Chalore; Fiaty, Koffi; Charcosset, Catherine

    2015-07-17

    During the last 10 years, membrane chromatography (MC) has been increasingly reported for biomolecule purification at both small and large scales. Although, several axial and radial flow MC devices are commercialized, the effect of the device dimensions on the adsorption performance has not been fully investigated. In this study, axial and radial flow anion ion-exchange MC devices were used for bovine serum albumin (BSA) adsorption. For both axial and radial flow, three devices at different scales were compared, two having similar diameter and two similar bed height. The pressure drop and the flow distribution using acetone as a non-binding solute were measured, as well as BSA breakthrough curves at different flow rates and BSA loading concentrations. For all devices, it was observed that the flow rate had no effect on the breakthrough curve, which confirms the advantage of MC to be used at high flow rates. In addition, the BSA binding capacity increased with increasing BSA concentration, which suggests that it could be preferable to work with concentrated solutions rather than with very dilute solutions, when using buffer at high phosphate concentration. For both axial and radial flow, the bed height had a negative impact on the binding capacity, as the lowest binding capacities per membrane volume were obtained with the devices having the highest bed height. Radial flow MC has potential at large-scale applications, as a short bed thickness can be combined with a large inlet surface area.

  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. 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.

  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. 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.

  8. Scaling thermal effects in radial flow

    NASA Astrophysics Data System (ADS)

    Hudspeth, R. T.; Guenther, R. B.; Roley, K. L.; McDougal, W. G.

    To adequately evaluate the environmental impact of siting nuclear waste repositories in basalt aquicludes, it is essential to know the effects on parameter identification algorithms of thermal gradients that exist in these basaltic aquicludes. Temperatures of approximately 60°C and pressures of approximately 150 atm can be expected at potential repository sites located at depths of approximately 1000 m. The phenomenon of over-recovery has been observed in some pumping tests conducted at the Hanford Nuclear Reservation located in the Pasco Basin adjacent to the Columbia River in the state of Washington, USA. This over-recovery phenomenon may possibly be due to variations in the fluid density caused by thermal gradients. To assess the potential effects of these thermal gradients on indirect parameter identification algorithms, a systematic scaling of the governing field equations is required in order to obtain dimensionless equations based on the principle of similarity. The constitutive relationships for the specific weight of the fluid and for the porosity of the aquiclude are shown to be exponentially dependent on the pressure gradient. The dynamic pressure is converted to the piezometric head and the flow equation for the piezometric head is then scaled in radial coordinates. Order-of-magnitude estimates are made for all variables in unsteady flow for a typical well test in a basaltic aquiclude. Retaining all nonlinear terms, the parametric dependency of the flow equation on the classical dimensionless thermal and hydraulic parameters is demonstrated. These classical parameters include the Batchelor, Fourier, Froude, Grashof, and Reynolds Numbers associated with thermal flows. The flow equation is linearized from order-of-magnitude estimates based on these classical parameters for application in parameter identification algorithms.

  9. Intraoperative in situ radial artery conduit flow assessment.

    PubMed

    Canver, Charles C; Yousafzai, Sajjad M

    2008-01-01

    A technique is described for simple flow assessment of the in situ radial artery conduit during coronary bypass via a small incision. This technique allows morphologic and physiologic direct intraoperative assessment of radial artery quality and expands the use of radial artery during coronary artery surgery.

  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. 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.

  12. 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

  13. 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.

  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. FUEL SUBASSEMBLY CONSTRUCTION FOR RADIAL FLOW IN A NUCLEAR REACTOR

    DOEpatents

    Treshow, M.

    1962-12-25

    An assembly of fuel elements for a boiling water reactor arranged for radial flow of the coolant is described. The ingress for the coolant is through a central header tube, perforated with parallel circumferertial rows of openings each having a lip to direct the coolant flow downward. Around the central tube there are a number of equally spaced concentric trays, closely fitiing the central header tube. Cylindrical fuel elements are placed in a regular pattern around the central tube, piercing the trays. A larger tube encloses the arrangement, with space provided for upward flow of coolart beyond the edge of the trays. (AEC)

  16. Macrodispersion by diverging radial flows in randomly heterogeneous porous media.

    PubMed

    Severino, Gerardo; Santini, Alessandro; Sommella, Angelo

    2011-04-01

    Radial flow takes place in a heterogeneous porous formation where the transmissivity T is modelled as a stationary random space function (RSF). The steady flow is driven by a given rate, and the mean velocity is radial. A pulse-like of a tracer is injected in the porous formation, and the thin plume spreads due to the fluctuations of the velocity which results a RSF as well. Transport is characterized by the mean front, and by the second spatial moment of the plume. We are primarily interested in tracer macrodispersion modelling. With the neglect of pore-scale dispersion, macrodispersion coefficients are computed at the second order of approximation, without neglecting the head-gradient fluctuations. Although transport is non-ergodic at the source, it is shown that ergodicity is achieved at small distances from the source. This is due to the fact that close to the source local velocities are quite large, and therefore solute particles become uncorrelated very soon. Under ergodic conditions, we compare macrodispersion mechanism in radial flows with that occurring in mean uniform flows. At short distances the spreading effect is highly enhanced by the large variability of the flow field, whereas at large distances transport exhibits a lesser dispersion due to the reduction of velocities. This supports the explanation provided by Indelman and Dagan (1999) to justify why the macrodispersivity is found smaller than that pertaining to mean uniform flows. The model is tested against a tracer transport experiment (Fernàndez-Garcia et al., 2004) by comparing the theoretical and experimental breakthrough curves. The accordance with real data, that is achieved without any fitting to concentration values, strengthens the capability of the proposed model to grasp the main features of such an experiment, the approximations as well as experimental uncertainties notwithstanding.

  17. Dynamics of particulate flow through radial-flow compressor and annular combustor

    SciTech Connect

    Elfeki, S.H.

    1987-01-01

    A theoretical study is presented of the particulate flows through a radial-flow compressor with two different-size splitters and an annular combustion chamber. Three elements of the radial-flow compressor are investigated, namely: the inlet part, the impeller with the two splitter, and the vaneless diffuser. For the annular combustion chamber, only the chamber is of concern. The three-dimensional flow-field analysis for the radial-flow compressor is presented with the corresponding solid-particle trajectories through the compressor. The well-known theory describing the particles' motion in a gas flow media is applied with accurate representation of the particle-trajectory paths. This accuracy is achieved by solving the three-dimensional flow field through the compressor. One new design concept is suggested for the radial-flow compressor with splitters. This concept is that the tangential spacing of the splitters with the full blades is selected on non-equally spaced basis with the spacing being equal at the impeller exit such that the flow rate is equally splitted among different channels in the cascade. In addition, a study of the particulate flows through the annular combustor is investigated. The nature of the flow in the combustor is three-dimensional turbulent and with reacting recirculating-flow characteristics.

  18. Onset of radial flow in p+p collisions

    DOE PAGES

    Jiang, Kun; Zhu, Yinying; Liu, Weitao; ...

    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

  19. 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.

  20. RADIAL FLOW PATTERN OF A SLOW CORONAL MASS EJECTION

    SciTech Connect

    Feng, Li; Gan, Weiqun; Inhester, Bernd

    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{sup −1}. In the Lagrangian frame, the speeds of the individual CME mass elements stay almost constant within 2 and 15 R{sub S}, 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Infant-specific gaze patterns in response to radial optic flow

    PubMed Central

    Shirai, Nobu; Imura, Tomoko

    2016-01-01

    The focus of a radial optic flow is a valid visual cue used to perceive and control the heading direction of animals. Gaze patterns in response to the focus of radial optic flow were measured in human infants (N = 100, 4–18 months) and in adults (N = 20) using an eye-tracking technique. Overall, although the adults showed an advantage in detecting the focus of an expansion flow (representing forward locomotion) against that of a contraction flow (representing backward locomotion), infants younger than 1 year showed an advantage in detecting the focus of a contraction flow. Infants aged between 13 and 18 months showed no significant advantage in detecting the focus in either the expansion or in the contraction flow. The uniqueness of the gaze patterns in response to the focus of radial optic flow in infants shows that the visual information necessary to perceive heading direction potentially differs between younger and mature individuals. PMID:27708361

  6. The Radial Flow Speed of the Neutral Hydrogen in the Oval Distortion of NGC 4736

    NASA Astrophysics Data System (ADS)

    Speights, Jason; Benton, Allen; Reimer, Rebecca; Lemaire, Robert; Godwin, Caleb

    2017-01-01

    Radial flows are difficult to measure in the presence of elliptical flows. This is because the model describing the observed velocity field when both kinds of flows are present is degenerate in the unknown parameters. In this poster we show that the degeneracy can be overcome if the pattern speed and position angle of the elliptical flows are known. The method is demonstrated for NGC 4736 using 3.6 micrometer and neutral hydrogen data. We find a mean inward radial flow speed of 5.6 +/- 1.7 km/s in the region of the oval distortion.

  7. Radial gas flow in the upper shaft and its influence on blast furnace performance

    SciTech Connect

    Beppler, E.; Kowalski, W.; Langner, K.; Wachsmuth, H.

    1996-12-31

    Knowledge of and control of gas flow in the upper shaft and over the blast furnace radius is an important factor for constant optimization of blast furnace performance in terms of fuel consumption and productivity. Radial gas flow in the blast furnace is generally controlled by the radial distribution of burden and coke. However, there are other influencing variables which determine radial gas flow, in particular central gas flow: (a) Increased sinter degradation displaces the cohesive zone downwards, constricting the gas flow between the dead man and the cohesive zone. This hinders central gas flow. (b) Lower coke strengths also lead to deterioration in gas flow between the dead man and the cohesive zone and hence to decline in central gas flow. (c) Decreasing coke layers in the blast furnace hinder central gas flow. (d) Increasing coal injection rates produce higher coke degradation in the blast furnace and hence also hinder central gas flow. (e) High coal rates and lower CSR values lead to shortening of combustion zone, which hinders the gas flow to the blast furnace center. (f) Finally, increasing hot metal-slag levels divert the gas to the outside. As the significance of the question of the central gas flow is growing,and because radial gas flow at Thyssen Stahl AG can only be measured sporadically with an in-burden probe, an inclined probe (inclination 35{degree}) just above the stock line was developed for simultaneous temperature measurement and gas sampling at 9 points along the radius.

  8. 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

  9. 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.

  10. Computer program for the analysis of the cross flow in a radial inflow turbine scroll

    NASA Technical Reports Server (NTRS)

    Hamed, A.; Abdallah, S.; Tabakoff, W.

    1977-01-01

    A computer program was used to solve the governing of the potential flow in the cross sectional planes of a radial inflow turbine scroll. A list of the main program, the subroutines, and typical output example are included.

  11. A flow study in radial inflow turbine scroll-nozzle assembly

    NASA Technical Reports Server (NTRS)

    Hamed, A.; Baskharone, E.; Tabakoff, W.

    1978-01-01

    The present analysis describes the flow behavior in the combined scroll-nozzle assembly of a radial inflow turbine. This model was chosen to provide a better understanding of the mutual interaction effects of these two components on the flow. The finite element method is used in the solution of the flow field in this multiply connected domain. The mass flow rates in the different nozzle channels is not presumed constant, but is determined from the solution.

  12. Experimental study of fluid dynamics in the pebble bed in a radial coolant flow

    NASA Astrophysics Data System (ADS)

    Smorchkova, Y. V.; Varava, A. N.; Dedov, A. V.; Komov, A. T.

    2016-10-01

    The results of experimental studies of pebble bed hydrodynamics are presented. For the first time experimental data on the pressure loss in a radial flow of fluid through the pebble bed was obtained. Experiments were carried out in the liquid flow rate ranging from 0.09 to 0.4 kg / s, fluid temperature is 20°C.

  13. Numerical and experimental study of unsteady flow field and vibration in radial inflow turbines

    SciTech Connect

    Kreuz-Ihli, T.; Filsinger, D.; Schulz, A.; Wittig, S.

    2000-04-01

    The blades of turbocharger impellers are exposed to unsteady aerodynamic forces, which cause blade vibrations and may lead to failures. An indispensable requirement for a safe design of radial inflow turbines is a detailed knowledge of the exciting forces. Up to now, only a few investigations relating to unsteady aerodynamic forces in radial turbines have been presented. To give a detailed insight into the complex phenomena, a comprehensive research project was initiated at the Institut fuer Thermische Stroemungsmaschinen, at the University of Karlsruhe. A turbocharger test rig was installed in the high-pressure, high-temperature laboratory of the institute. The present paper gives a description of the test rig design and the measuring techniques. The flow field in a vaneless radial inflow turbine was analyzed using laser-Doppler anemometry. First results of unsteady flow field investigations in the turbine scroll and unsteady phase-resolved measurements of the flow field in the turbine rotor will be discussed. Moreover, results from finite element calculations analyzing frequencies and mode shapes are presented. As vibrations in turbines of turbochargers are assumed to be predominantly excited by unsteady aerodynamic forces, a method to predict the actual transient flow in a radial turbine utilizing the commercial Navier-Stokes solver TASCflow3d was developed. Results of the unsteady calculations are presented and comparisons with the measured unsteady flow field are made. As a major result, the excitation effect of the tongue region in a vaneless radial inflow turbine can be demonstrated.

  14. Analysis of the cross flow in a radial inflow turbine scroll

    NASA Technical Reports Server (NTRS)

    Hamed, A.; Abdallah, S.; Tabakoff, W.

    1977-01-01

    Equations of motion were derived, and a computational procedure is presented, for determining the nonviscous flow characteristics in the cross-sectional planes of a curved channel due to continuous mass discharge or mass addition. An analysis was applied to the radial inflow turbine scroll to study the effects of scroll geometry and the through flow velocity profile on the flow behavior. The computed flow velocity component in the scroll cross-sectional plane, together with the through flow velocity profile which can be determined in a separate analysis, provide a complete description of the three dimensional flow in the scroll.

  15. Investigations on the Aerodynamic Characteristics and Blade Excitations of the Radial Turbine with Pulsating Inlet Flow

    NASA Astrophysics Data System (ADS)

    Liu, Yixiong; Yang, Ce; Yang, Dengfeng; Zhang, Rui

    2016-04-01

    The aerodynamic performance, detailed unsteady flow and time-based excitations acting on blade surfaces of a radial flow turbine have been investigated with pulsation flow condition. The results show that the turbine instantaneous performance under pulsation flow condition deviates from the quasi-steady value significantly and forms obvious hysteretic loops around the quasi-steady conditions. The detailed analysis of unsteady flow shows that the characteristic of pulsation flow field in radial turbine is highly influenced by the pulsation inlet condition. The blade torque, power and loading fluctuate with the inlet pulsation wave in a pulse period. For the blade excitations, the maximum and the minimum blade excitations conform to the wave crest and wave trough of the inlet pulsation, respectively, in time-based scale. And toward blade chord direction, the maximum loading distributes along the blade leading edge until 20% chord position and decreases from the leading to trailing edge.

  16. Phase Change Effects on Immiscible Flow Displacements in Radial Injection

    NASA Astrophysics Data System (ADS)

    Ahmadlouydarab, Majid; Azaiez, Jalel; Chen, Zhangxin

    2014-11-01

    We report a systematic simulation of immiscible fluid-fluid displacements in radial injection in the presence of phase change. Due to the presence of two fluid-fluid interfaces in the system, a special treatment has been adopted. To track the leading interface position, two highly accurate methods including Level Set and Immersed Interface Method were used, while for locating the trailing interface an energy equation was adopted assuming the existence of a constant thin condensate layer. Dimensional analysis led to three important dimensionless groups including capillary number (Ca), Jacob number (Ja) and viscosity ratios (M) of the three fluids. Simulation results indicate significant influences of these parameters on the development of the instability and the interfacial morphology of fingers. Increasing Ca or M tends to amplify the interfacial instability, fingertip splitting, and results in longer fingers. In contrast, increasing Ja has stabilizing effects due to an increase of the thickness of the condensate layer. On the other hand at lower viscosity ratios as well as lower Ca, because of compensation effects of the phase change, both leading and trailing interfaces are found to be less unstable. Moreover accumulated condensate and oil saturation depletion curves show increasing and decreasing trends, respectively, when the Ca increases. Although viscosity ratio and Ja have similar effects on the accumulated condensate, they do not show any effect on the oil depletion saturation.

  17. Radial Flow Effects On A Retreating Rotor Blade

    DTIC Science & Technology

    2014-05-01

    measurements was to ensure the static wing was at the same effective angle of attack as the rotating blade (accounting for inflow and blade flapping ). The pitch ...a delta wing . (d) The area of the separated flow near the mount is expected to reduce for a larger aspect ratio wing since the mount induced adverse...is to model the effect of reverse flow on rotating blades using a delta wing analogy. The analysis of the lift-to-drag ratio and pitching moment

  18. Radial variation in sap flow in five laurel forest tree species in Tenerife, Canary Islands.

    PubMed

    Jiménez, M. Soledad; Nadezhdina, Nadezhda; Cermák, Jan; Morales, Domingo

    2000-11-01

    Variations in radial patterns of xylem water content and sap flow rate were measured in five laurel forest tree species (Laurus azorica (Seub.) Franco, Persea indica (L.) Spreng., Myrica faya Ait., Erica arborea L. and Ilex perado Ait. ssp. platyphylla (Webb & Berth.) Tutin) growing in an experimental plot at Agua García, Tenerife, Canary Islands. Measurements were performed around midday during warm and sunny days by the heat field deformation method. In all species, water content was almost constant (around 35% by volume) over the whole xylem cross-sectional area. There were no differences in wood color over the whole cross-sectional area of the stem in most species with the exception of E. arborea, whose wood became darker in the inner layers. Radial patterns of sap flow were highly variable and did not show clear relationships with tree diameter or species. Sap flow occurred over the whole xylem cross-sectional area in some species, whereas it was limited to the outer xylem layers in others. Sap flow rate was either similar along the xylem radius or exhibited a peak in the outer part of the xylem area. Low sap flow rates with little variation in radial pattern were typical for shaded suppressed trees, whereas dominant trees exhibited high sap flow rates with a peak in the radial pattern. Stem damage resulted in a significant decrease in sap flow rate in the outer xylem layers. The outer xylem is more important for whole tree water supply than the inner xylem because of its larger size. We conclude that measurement of radial flow pattern provides a reliable method of integrating sap flow from individual measuring points to the whole tree.

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

    USGS Publications Warehouse

    Pucci, A.A.; 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. 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.

  1. 3-D model of a radial flow sub-watt methanol fuel processor

    SciTech Connect

    Holladay, J. D.; Wang, Y.

    2015-10-01

    A 3-D model is presented for a novel sub-watt packed bed reactor. The reactor uses an annular inlet flow combined with a radial flow packed bed reactor. The baseline reactor is compared to a reactor with multiple outlets and a reactor with 3 internal fins. Increasing the outlets from 1 to 4 did improve the flow distribution, but did not increase the performance in the simulation. However, inserting fins allowed a decrease in temperature with same inlet flow of approximately 35K. Or the inlet flow rate could be increased by a factor of 2.8x while maintaining >99% conversion.

  2. 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

  3. Determination of radial electric field from Pfirsch–Schlüter flows in the HSX stellarator

    NASA Astrophysics Data System (ADS)

    Kumar, S. T. A.; Talmadge, J. N.; Dobbins, T. J.; Anderson, F. S. B.; Likin, K. M.; Anderson, D. T.

    2017-03-01

    Inboard/outboard asymmetry in the impurity ion parallel flow is observed in the HSX stellarator using charge exchange recombination spectroscopy (CHERS). This observation shows the presence of counter-streaming Pfirsch–Schlüter flow predicted by neoclassical theory. The asymmetry of the flow is used to calculate the magnitude and direction of the radial electric field (E r), as well as the mean flow, using computed magnetic geometry factors. This method enables calculation of E r near the core of the HSX plasma where the E r obtained from the radial force balance equation has large uncertainties due to the relatively large width of the diagnostic neutral beam with respect to the plasma minor radius.

  4. Prediction of heat transfer to a thin liquid film in plane and radially spreading flows

    NASA Technical Reports Server (NTRS)

    Rahman, M. M.; Faghri, A.; Hankey, W. L.; Swanson, T. D.

    1990-01-01

    The energy equation is incorporated in the solution algorithm of Rahman et al. (1990) to compute the heat transfer to a thin film in the presence or absence of gravity. For a plane flow under zero gravity, it is found that, for both isothermal and uniformly heated walls, the heat transfer coefficient gradually decreases downstream, with Nu-asterisk (the Nusselt number in terms of film height) remaining approximately constant except for regions very close to the entrance. In the case of radial flow under zero gravity, Nu-asterisk is found to decrease monotonically when the plane is uniformly heated. Two different flow regimes are identified in the presence of gravity for both plane and radial flows. The results of the study may be applicable to the design of space-based cooling systems.

  5. Temperature gradients drive radial fluid flow in Petri dishes and multiwell plates.

    PubMed

    Lindsay, Stephen M; Yin, John

    2016-06-01

    Liquid in a Petri dish spontaneously circulates in a radial pattern, even when the dish is at rest. These fluid flows have been observed and utilized for biological research, but their origins have not been well-studied. Here we used particle-tracking to measure velocities of radial fluid flows, which are shown to be linked to evaporation. Infrared thermal imaging was used to identify thermal gradients at the air-liquid interface and at the bottom of the dish. Two-color ratiometric fluorescence confocal imaging was used to measure thermal gradients in the vertical direction within the fluid. A finite-element model of the fluid, incorporating the measured temperature profiles, shows that buoyancy forces are sufficient to produce flows consistent with the measured particle velocity results. Such flows may arise in other dish or plate formats, and may impact biological research in positive or negative ways.

  6. 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...

  7. 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 ...

  8. Diurnal and seasonal variability in the radial distribution of sap flow: predicting total stem flow in Pinus taeda trees.

    PubMed

    Ford, Chelcy R; Goranson, Carol E; Mitchell, Robert J; Will, Rodney E; Teskey, Robert O

    2004-09-01

    We monitored the radial distribution of sap flux density (v; g H2O m(-2) s(-1)) in the sapwood of six plantation-grown Pinus taeda L. trees during wet and dry soil periods. Mean basal diameter of the 32-year-old trees was 33.3 cm. For all trees, the radial distribution of sap flow in the base of the stem (i.e., radial profile) was Gaussian in shape. Sap flow occurred maximally in the outer 4 cm of sapwood, comprising 50-60% of total stem flow (F), and decreased toward the center, with the innermost 4 cm of sapwood (11-15 cm) comprising less than 10% of F. The percent of flow occurring in the outer 4 cm of sapwood was stable with time (average CV < 10%); however, the percentage of flow occurring in the remaining sapwood was more variable over time (average CV > 40%). Diurnally, the radial profile changed predictably with time and with total stem flow. Seasonally, the radial profile became less steep as the soil water content (theta) declined from 0.38 to 0.21. Throughout the season, daytime sap flow also decreased as theta decreased; however, nighttime sap flow (an estimate of stored water use) remained relatively constant. As a result, the percentage of stored water use increased as theta declined. Time series analysis of 15-min values of F, theta, photosynthetically active radiation (PAR) and vapor pressure deficit (D) showed that F lagged behind D by 0-15 min and behind PAR by 15-30 min. Diurnally, the relationship between F and D was much stronger than the relationship between F and PAR, whereas no relationship was found between F and theta. An autoregressive moving average (ARIMA) model estimated that 97% of the variability in F could be predicted by D alone. Although total sap flow in all trees responded similarly to D, we show that the radial distribution of sap flow comprising total flow could change temporally, both on daily and seasonal scales.

  9. 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.

  10. Investigation of Ultrasound-Measured Flow Velocity, Flow Rate and Wall Shear Rate in Radial and Ulnar Arteries Using Simulation.

    PubMed

    Zhou, Xiaowei; Xia, Chunming; Stephen, Gandy; Khan, Faisel; Corner, George A; Hoskins, Peter R; Huang, Zhihong

    2017-02-21

    Parameters of blood flow measured by ultrasound in radial and ulnar arteries, such as flow velocity, flow rate and wall shear rate, are widely used in clinical practice and clinical research. Investigation of these measurements is useful for evaluating accuracy and providing knowledge of error sources. A method for simulating the spectral Doppler ultrasound measurement process was developed with computational fluid dynamics providing flow-field data. Specific scanning factors were adjusted to investigate their influence on estimation of the maximum velocity waveform, and flow rate and wall shear rate were derived using the Womersley equation. The overestimation in maximum velocity increases greatly (peak systolic from about 10% to 30%, time-averaged from about 30% to 50%) when the beam-vessel angle is changed from 30° to 70°. The Womersley equation was able to estimate flow rate in both arteries with less than 3% error, but performed better in the radial artery (2.3% overestimation) than the ulnar artery (15.4% underestimation) in estimating wall shear rate. It is concluded that measurements of flow parameters in the radial and ulnar arteries with clinical ultrasound scanners are prone to clinically significant errors.

  11. Experimental characterization of the Taylor-Couette flow submitted to a radial temperature gradient

    NASA Astrophysics Data System (ADS)

    Prigent, Arnaud; Guillerm, Rapha"El; Mutabazi, Innocent; Yang, Kyung-Soo

    2009-11-01

    We have developed a non-intrusive velocity and temperature fields measurement technique using thermochromic liquid crystals which allows to fully characterize the flow produced in a narrow gap and large aspect ratio Couette-Taylor system submitted to a radial temperature gradient. The aspect ratio and radius ratio of the system are respectively equal to 112 and 0.8. The control parameters are the Grashof number Gr, related to the radial temperature gradient, and the Taylor number Ta, related to the rotation of the inner cylinder. Here, Gr is fixed and Ta is gradually increased. For small values of Ta, the base flow is composed of the circular Couette flow and a vertical flow induced by the radial temperature gradient. Above a critical value of Ta, the destabilization of the base flow gives rise to a spiral pattern. While for small Gr values it corresponds to traveling inclined vortices, for large Gr values it corresponds to a modulated wave-like pattern filling the whole length of the system and rotating at the mean angular velocity of the flow. When Ta is further increased, this wave-like pattern is progressively replaced by a counter-rotating vortices pattern. Numerical simulations of the corresponding Boussinesq-Oberbeck equations provide results in good agreement with experiments.

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

    PubMed Central

    González Fernández-Niño, 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

  13. Breakdown of Burton Prim Slichter approach and lateral solute segregation in radially converging flows

    NASA Astrophysics Data System (ADS)

    Priede, J.; Gerbeth, G.

    2005-11-01

    A theoretical study is presented of the effect of a radially converging melt flow, which is directed away from the solidification front, on the radial solute segregation in simple solidification models. We show that the classical Burton-Prim-Slichter (BPS) solution describing the effect of a diverging flow on the solute incorporation into the solidifying material breaks down for the flows converging along the solidification front. The breakdown is caused by a divergence of the integral defining the effective boundary layer thickness which is the basic concept of the BPS theory. Although such a divergence can formally be avoided by restricting the axial extension of the melt to a layer of finite height, radially uniform solute distributions are possible only for weak melt flows with an axial velocity away from the solidification front comparable to the growth rate. There is a critical melt velocity for each growth rate at which the solution passes through a singularity and becomes physically inconsistent for stronger melt flows. To resolve these inconsistencies we consider a solidification front presented by a disk of finite radius R0 subject to a strong converging melt flow and obtain an analytic solution showing that the radial solute concentration depends on the radius r as ˜ln(R0/r) and ˜ln(R0/r) close to the rim and at large distances from it. The logarithmic increase of concentration is limited in the vicinity of the symmetry axis by the diffusion becoming effective at a distance comparable to the characteristic thickness of the solute boundary layer. The converging flow causes a solute pile-up forming a logarithmic concentration peak at the symmetry axis which might be an undesirable feature for crystal growth processes.

  14. Laminar flow between a stationary and a rotating disk with radial throughflow

    SciTech Connect

    Nesreddine, H.; Nguyen, C.T.; Vo-Ngoc, D.

    1995-05-01

    The problem of axisymmetric laminar flow of a viscous incompressible fluid that occurs between a stationary and a rotating disk subjected to a uniform radial throughflow has been numerically investigated for a large range of flow parameters. Results show that the basic flow structure is rather complex and depends strongly on both the rotational and the flow structure is rather complex and depends strongly on both the rotational and the throughflow Reynolds numbers. In general, the basic unicellular structure has been observed. With the increase of the throughflow Reynolds number, a multicellular flow structure may be found. The phenomenon of multiple solutions has been clearly observed for cases with sufficiently high rational Re and/or high throughflow Re. Among these solutions, stable as well as unstable solutions have been determined by applying Rayleigh`s stability criterion. The influence of the starting conditions on the stability of the flow has also been investigated for various ranges of flow parameters.

  15. Simulating MODFLOW-based reactive transport under radially symmetric flow conditions.

    PubMed

    Wallis, Ilka; Prommer, Henning; Post, Vincent; Vandenbohede, Alexander; Simmons, Craig T

    2013-01-01

    Radially symmetric flow and solute transport around point sources and sinks is an important specialized topic of groundwater hydraulics. Analysis of radial flow fields is routinely used to determine heads and flows in the vicinity of point sources or sinks. Increasingly, studies also consider solute transport, biogeochemical processes, and thermal changes that occur in the vicinity of point sources/sinks. Commonly, the analysis of hydraulic processes involves numerical or (semi-) analytical modeling methods. For the description of solute transport, analytical solutions are only available for the most basic transport phenomena. Solving advanced transport problems numerically is often associated with a significant computational burden. However, where axis-symmetry applies, computational cost can be decreased substantially in comparison with full three-dimensional (3D) solutions. In this study, we explore several techniques of simulating conservative and reactive transport within radial flow fields using MODFLOW as the flow simulator, based on its widespread use and ability to be coupled with multiple solute and reactive transport codes of different complexity. The selected transport simulators are MT3DMS and PHT3D. Computational efficiency and accuracy of the approaches are evaluated through comparisons with full 2D/3D model simulations, analytical solutions, and benchmark problems. We demonstrate that radial transport models are capable of accurately reproducing a wide variety of conservative and reactive transport problems provided that an adequate spatial discretization and advection scheme is selected. For the investigated test problems, the computational load was substantially reduced, with the improvement varying, depending on the complexity of the considered reaction network.

  16. 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.

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

    PubMed

    Chen, Ching-Yao; Huang, Yi-Cheng; Huang, Yu-Sheng; Miranda, José 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 (Péclet number Pe, viscosity contrast A, and injection time interval Δt) on fluid mixing performance.

  18. Radial flow from electromagnetic probes and signal of quark gluon plasma

    SciTech Connect

    Mohanty, Payal; Nayak, Jajati K.; Alam, Jan-e; Das, Santosh K.

    2010-09-15

    An attempt has been made to extract the evolution of radial flow from the analysis of the experimental data on electromagnetic probes measured at the energies available at the CERN Super Proton Synchrotron (SPS) and the BNL Relativistic Heavy Ion Collider (RHIC). The transverse momentum (p{sub T}) spectra of photons and dileptons measured by the WA98 and NA60 Collaborations, respectively, at the SPS and the photon and dilepton spectra obtained by the PHENIX Collaboration at the RHIC have been used to constrain the theoretical models. We use the ratio of photon to dilepton spectra to extract the flow, where some model dependence is canceled out. Within the ambit of the present analysis we argue that the variation of the radial velocity with invariant mass is indicative of a phase transition from the initially produced partons to hadrons at SPS and RHIC energies.

  19. 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.

  20. Effects of Purge-Flow Rate on Microbubble Capture in Radial Arterial-Line Filters

    PubMed Central

    Herbst, Daniel P.

    2016-01-01

    Abstract: The process of microbubble filtration from blood is complex and highly dependent on the forces of flow and buoyancy. To protect the patient from air emboli, arterial-line filters commonly use a micropore screen, a large volume housing with purpose-built shape, and a purge port to trap, separate, and remove circulating microbubbles. Although it has been proposed that an insufficient buoyancy force renders the purge port ineffective at removing microbubbles smaller than 500 μm, this research attempts to investigate the purge flow of an arterial-line filter to better understand the microbubble removal function in a typical radial filter design. As its primary objective, the study aims to determine the effect of purge-flow rate on bubble capture using air bolus injections from a syringe pump with 22-gauge needle and Doppler ultrasound bubble detection. The measureable bubble size generated in the test circuit ranged between 30 and 500 μm, while purge flow was varied between .1 and .5 L/min for testing. Statistical analysis of the test data was handled using a repeated measures design with significance set at p < .05 level. Outcomes demonstrated that higher purge flows yielded higher bubble counts, but the effect of purge-flow rate on bubble capture decreased as bubble size increased. Results also showed that purge flow from the test filter was capable of capturing all bubble sizes being generated over the entire flow range tested, and confirms utility of the purge port in removing microbubbles smaller than 500 μm. By analyzing bubble counts in the purge flow of a typical radial-filter design, this study demonstrates that currently available micropore filter technology is capable of removing the size range of bubbles that commonly pass through modern pump-oxygenator systems and should continue to be considered during extracorporeal circulation as a measure to improve patient safety. PMID:27729703

  1. Effects of Purge-Flow Rate on Microbubble Capture in Radial Arterial-Line Filters.

    PubMed

    Herbst, Daniel P

    2016-09-01

    The process of microbubble filtration from blood is complex and highly dependent on the forces of flow and buoyancy. To protect the patient from air emboli, arterial-line filters commonly use a micropore screen, a large volume housing with purpose-built shape, and a purge port to trap, separate, and remove circulating microbubbles. Although it has been proposed that an insufficient buoyancy force renders the purge port ineffective at removing microbubbles smaller than 500 μm, this research attempts to investigate the purge flow of an arterial-line filter to better understand the microbubble removal function in a typical radial filter design. As its primary objective, the study aims to determine the effect of purge-flow rate on bubble capture using air bolus injections from a syringe pump with 22-gauge needle and Doppler ultrasound bubble detection. The measureable bubble size generated in the test circuit ranged between 30 and 500 μm, while purge flow was varied between .1 and .5 L/min for testing. Statistical analysis of the test data was handled using a repeated measures design with significance set at p < .05 level. Outcomes demonstrated that higher purge flows yielded higher bubble counts, but the effect of purge-flow rate on bubble capture decreased as bubble size increased. Results also showed that purge flow from the test filter was capable of capturing all bubble sizes being generated over the entire flow range tested, and confirms utility of the purge port in removing microbubbles smaller than 500 μm. By analyzing bubble counts in the purge flow of a typical radial-filter design, this study demonstrates that currently available micropore filter technology is capable of removing the size range of bubbles that commonly pass through modern pump-oxygenator systems and should continue to be considered during extracorporeal circulation as a measure to improve patient safety.

  2. Convection in rotating flows with simultaneous imposition of radial and vertical temperature gradients

    NASA Astrophysics Data System (ADS)

    Banerjee, Ayan Kumar; Bhattacharya, Amitabh; Balasubramanian, Sridhar

    2016-11-01

    Laboratory experiments, with a rotating cylindrical annulus and thermal gradient in both radial and vertical directions (so that radial temperature difference decreases with the elevation), were conducted to study the convection dynamics and heat transport. Temperature data captured using thermocouples, combined with ANSYS Fluent simulation hinted at the co-existence of thermal plume and baroclinicity (inclined isotherms). Presence of columnar plume structure parallel to the rotation axis was found, which had a phase velocity and aided in vertical heat transport. Nusselt number (Nu) plotted as a function of Taylor number (Ta) showed the effect of rotation on heat transport in such systems, where the interplay of plumes and baroclinic waves control the scalar transport. Laser based PIV imaging at a single vertical plane also showed evidence of such flow structures.

  3. Cyclic and radial variation of ultrasonic backscatter from flowing porcine blood

    NASA Astrophysics Data System (ADS)

    Paeng, Dong-Guk

    The ultrasonic backscattering from flowing blood was investigated using several hemodynamic parameters and a physiological parameter. Acceleration was hypothesized to enhance the aggregation of red blood cells (RBCs), and this is the first time that acceleration is suggested and experimentally verified as having an effect on aggregation of RBC. Two interesting phenomena, the 'Black Hole (BH)' phenomenon and the 'Bright Collapsing Ring (BCR)' phenomenon, were observed under pulsatile flow in B-mode cross sectional images. The BH phenomenon describes a dark hypoechoic hole at the center of the tube surrounded by a bright hyperechoic zone in B-mode cross sectional images, and the BCR phenomenon describes the appearance of a bright hyperechoic ring at the periphery of the tube at early systole and its convergence from the periphery to the center of the tube, finally collapsing as flow develops. Doppler power variation was observed only from porcine whole blood, which led to a conclusion that the ultrasonic backscattering was mainly dependent on the RBC aggregation under steady and pulsatile flow. The pattern of the cyclic variation of the Doppler power to have a maximum power at peak systole was mainly due to the enhanced rouleaux formation by acceleration. The BCR phenomenon was observed from the cyclic variation pattern of the Doppler power at different radial positions; the Doppler power peak was observed at early systole at the periphery of the tube and lagged the flow as close from the periphery to the center of the tube. The BCR phenomenon from porcine whole blood in a mock flow loop was further examined in real time in B-mode images under pulsatile flow. At low hematocrit of 12%, no BCR phenomenon was discernable although it was observed at higher hematocrits. The pattern of the nonlinear relationship between echogenicity and hematocrit varied with radial positions. The BH phenomenon was also observed under certain hemodynamic conditions and varied over a

  4. Modeling of transient flow through a viscoelastic preparative chromatography packing.

    PubMed

    Hekmat, Dariusch; Kuhn, Michael; Meinhardt, Verena; Weuster-Botz, Dirk

    2013-01-01

    The common method for purification of macromolecular bioproducts is preparative packed-bed chromatography using polymer-based, compressible, viscoelastic resins. Because of a downstream processing bottleneck, the chromatography equipment is often operated at its hydrodynamic limit. In this case, the resins may exhibit a complex behavior which results in compression-relaxation hystereses. Up to now, no modeling approach of transient flow through a chromatography packing has been made considering the viscoelasticity of the resins. The aim of the present work was to develop a novel model and compare model calculations with experimental data of two agarose-based resins. Fluid flow and bed permeability were modeled by Darcy's law and the Kozeny-Carman equation, respectively. Fluid flow was coupled to solid matrix stress via an axial force balance and a continuity equation of a deformable packing. Viscoelasticity was considered according to a Kelvin-Voigt material. The coupled equations were solved with a finite difference scheme using a deformable mesh. The model boundary conditions were preset transient pressure drop functions which resemble simulated load/elution/equilibration cycles. Calculations using a homogeneous model (assuming constant variables along the column height) gave a fair agreement with experimental data with regard to predicted flow rate, bed height, and compression-relaxation hysteresis for symmetric as well as asymmetric pressure drop functions. Calculations using an inhomogeneous model gave profiles of the bed porosity as a function of the bed height. In addition, the influence of medium wall support and intraparticle porosity was illustrated. The inhomogeneous model provides insights that so far are not easily experimentally accessible.

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

    SciTech Connect

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

    2015-12-15

    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 Re{sub i} (inner cylinder) =1000 and Re{sub o} (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 < Re{sub o} < 500 in presence of buoyancy (σ = 0.1) with Re{sub i} = 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 R{sub rz} are observed for the strongly counter-rotating regimes (Re{sub o} = − 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

  6. 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.

  7. The numerical simulation of Taylor-Couette flow with radial temperature gradient

    NASA Astrophysics Data System (ADS)

    Tuliszka-Sznitko, E.; Kiełczewski, K.

    2016-10-01

    The Taylor-Couette flow with radial temperature gradient is a canonical problem for the study of heat transfer in engineering issues. However, gaining insight into the transitional Taylor-Couette flow with temperature gradient still requires detailed experimental and numerical investigations. In the present paper we have performed computations for the cavity of aspect ratio Γ= 3.76 and radii ratios η= 0.82 and 0.375 with the heated rotating bottom disk and stationary outer cylinder. We analyse the influence of the end-wall boundary conditions and the thermal conditions on the flow structure, and on the distributions of the Nusselt number and torque along the inner and outer cylinders. The averaged values along the inner cylinder of the Nusselt number and torque obtained for different Re are analysed in the light of the results published in [2, 16, 17].

  8. Application of radial-equilibrium condition to axial-flow compressor and turbine design

    NASA Technical Reports Server (NTRS)

    Wu, Chung-Hua; Wolfenstein, Lincoln

    1950-01-01

    Basic general equations governing the three-dimensional compressible flow of gas through a compressor or turbine are given in terms of total enthalpy, entropy, and velocity components of the gas. Two methods of solution are obtained for the simplified, steady axially symmetric flow; one involves the use of a number of successive planes normal to the axis of the machine and short distances apart, and the other involves only three stations for a stage in which an appropriate radial-flow path is used. Methods of calculation for the limiting cases of zero and infinite blade aspect ratios and an approximate method of calculation for finite blade aspect ratio are also given. In these methods, the blade loading and the shape of the annular passage wall may be arbitrarily specified.

  9. Tracer Migration in a Radially Divergent Flow Field: Longitudinal Dispersivity and Anionic Tracer Retardation

    SciTech Connect

    Seaman, J.C., P.M. Bertsch, M. Wilson, J. Singer, F. Majs and S.A. Aburime

    2007-01-01

    Hydrodynamic dispersion, the combined effects of chemical diffusion and differences in solute path length and flow velocity, is an important factor controlling contaminant migration in the subsurface environment. However, few comprehensive three-dimensional datasets exist for critically evaluating the impact of travel distance and site heterogeneity on solute dispersion, and the conservative nature of several commonly used groundwater tracers is still in question. Therefore, we conducted a series of field-scale experiments using tritiated water ({sup 3}H{sup 1}HO), bromide (Br{sup -}), and two fluorobenzoates (2,4 Di-FBA, 2,6 Di-FBA) as tracers in the water-table aquifer on the USDOE's Savannah River Site (SRS), located on the upper Atlantic Coastal Plain. For each experiment, tracer-free groundwater was injected for approximately 24 h (56.7 L min{sup -1}) to establish a steady-state forced radial gradient before the introduction of a tracer pulse. After the tracer pulse, which lasted from 256 to 560 min, the forced gradient was maintained throughout the experiment using nonlabeled groundwater. Tracer migration was monitored using six multilevel monitoring wells, radially spaced at approximate distances of 2.0, 3.0, and 4.5 m from the central injection well. Each sampling well was further divided into three discrete sampling depths that were pumped continuously ({approx}0.1 L min{sup -1}) throughout the course of the experiments. Longitudinal dispersivity ({alpha}{sub L}) and travel times for {sup 3}H{sup 1}HO breakthrough were estimated by fitting the field data to analytical approximations of the advection-dispersion equation (ADE) for uniform and radial flow conditions. Dispersivity varied greatly between wells located at similar transport distances and even between zones within a given well, which we attributed to variability in the hydraulic conductivity at the study site. The radial flow equation generally described tritium breakthrough better than the

  10. Radial Dupuit interface flow to assess the aquifer storage and recovery potential of saltwater aquifers

    NASA Astrophysics Data System (ADS)

    Bakker, Mark

    2010-02-01

    A new accurate numerical solution is presented for aquifer storage and recovery (ASR) systems in coastal aquifers; flow is approximated as radial Dupuit interface flow. The radial velocities of points on the interface are a function of time, the vertical coordinate, and the dimensionless parameter D (the discharge of the well divided by the product of the hydraulic conductivity, the square of the aquifer thickness, and the dimensionless density difference). The recovery efficiency of an ASR system (the ratio of the recovered volume of water divided by the injected volume of water) is determined by D and by the relative lengths of the injection, storage and recovery periods. Graphs are produced for the recovery efficiency as a function of parameter D for ASR operations with and without storage periods and for multiple cycles. The presented solutions and graphs are to be used as screening tools to assess the feasibility of specific injection, storage and recovery scenarios of planned ASR systems in saltwater aquifers without having to run complicated flow and transport models. When the screening tool indicates that recovery efficiencies are acceptable, the consideration of other features such as mixing and chemistry is warranted.

  11. Radial flow fuel nozzle for a combustor of a gas turbine

    DOEpatents

    Means, Gregory Scott; Boardman, Gregory Allen; Berry, Jonathan Dwight

    2016-07-05

    A combustor for a gas turbine generally includes a radial flow fuel nozzle having a fuel distribution manifold, and a fuel injection manifold axially separated from the fuel distribution manifold. The fuel injection manifold generally includes an inner side portion, an outer side portion, and a plurality of circumferentially spaced fuel ports that extend through the outer side portion. A plurality of tubes provides axial separation between the fuel distribution manifold and the fuel injection manifold. Each tube defines a fluid communication path between the fuel distribution manifold and the fuel injection manifold.

  12. Consideration of Inner and Outer Phase Configuration in Tube Radial Distribution Phenomenon Based on Viscous Dissipation in a Microfluidic Flow Using Various Types of Mixed Solvent Solutions.

    PubMed

    Fujinaga, Satoshi; Hashimoto, Masahiko; Tsukagoshi, Kazuhiko; Mizushima, Jiro

    2016-01-01

    When mixed solvent solutions, such as ternary water-hydrophilic/hydrophobic organic solvents, water-surfactant, and water-ionic liquid, are delivered into a microspace under laminar flow conditions, the solvent molecules radially distribute in the microspace, generating inner and outer phases. This specific fluidic behavior is termed "tube radial distribution phenomenon", and has been used in separation technologies such as chromatography and extraction. The factors influencing the configuration of the inner and outer phases in "tube radial distribution phenomenon" using the above-mentioned mixed solvent solutions were considered from the viewpoint of viscous dissipation in fluidic flows. When the difference in the viscosity between the two phases was large (approximately >0.73 mPa·s), the phase with the higher viscosity formed as an inner phase regardless of the volume ratio. The distribution pattern of the solvents was supported by the viscous dissipation principle. Contrarily, when the difference was small (approximately <0.49 mPa·s), the phase with the larger volume formed as the inner phase. The distribution pattern of the solvents did not always correspond to the viscous dissipation principle. The current findings are expected to be useful in analytical science including microflow analysis research.

  13. Effect of dextran 500 on radial migration of erythrocytes in postcapillary venules at low flow rates.

    PubMed

    Kim, Sangho; Ong, Peng Kai; Johnson, Paul C

    2009-06-01

    Recently, we reported that collision efficiency (fraction of total collisions that result in the formation of aggregates) between red blood cells was an important factor in the formation of aggregates in postcapillary venules. In the present study, we focus on how high molecular weight dextran influences the overall radial migration trend of red blood cells in the postcapillary venule along a longitudinal distance of 50 microm from the bifurcation which would in turn affect collision behavior of these cells. A radial migration index, which defines the extent of radial migration of individual cells relative to the vessel center, was found to have a larger magnitude after infusion of dextran (1.9 +/- 2.73) compared to that before dextran infusion (1.48 +/- 3.89). This implied that dextran-induced aggregation might provide an external force to actively move cells towards the centerline of the vessel, which could contribute to the greater number of red blood cells participating in collision (16% increase) and aggregate formation. Further analysis of the collision behavior of individual red blood cells revealed that collision frequencies of individual cells decreased from a wide range (1 to 14) to a narrow range (1 to 5) after dextran treatment, indicating the alteration of collision behavior of red blood cells by the presence of aggregates along the flow stream.

  14. 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.

  15. 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.

  16. Radially-Inflowing Molecular Gas Deposited by a X-ray Cooling Flow

    NASA Astrophysics Data System (ADS)

    Lim, Jeremy; Ao, Y.; Dinh, V.

    2006-12-01

    Galaxy clusters are immersed in hot X-ray-emitting gas that constitutes a large fraction of their baryonic mass. Radiative cooling of this gas, if not adequately balanced by heat input, should result in an inflow of cooler gas to the central dominant giant elliptical (cD) galaxy. Although a straightforward prediction made nearly twenty years ago, the occurrence of such X-ray cooling flows is widely questioned as gas at lower temperatures is often not found at the predicted quantities. The exceptions are cD galaxies harbouring large quantities of cool molecular gas, but the origin of this gas is uncertain as ram-pressure stripping or cannibalism of gas-rich cluster galaxies provide viable alternatives to cooling flows. Here, we present the most direct evidence yet for the deposition of molecular gas in a cD galaxy, Perseus A, from a X-ray cooling flow. The molecular gas detected in this galaxy is concentrated in three radial filaments with projected lengths of at least 2 kpc, one extending inwards close to the active nucleus and the other two extending outwards to at least 8 kpc on the east and west. All three filaments coincide with bright Hα features, and lie along a central X-ray ridge where any cooling flow is strongest. The two outer filaments exhibit increasingly blueshifted velocities at smaller radii that we show trace radial inflow along the gravitational potential of the galaxy. The innermost filament appears to be settling into the potential well, and may fuel the central supermassive black hole whose radio jets heat gas over a large solid angle in the north-south direction. Our results demonstrate that X-ray cooling flows can indeed deposit large quantities of cool gas, but only intermittently along directions where the X-ray gas is not being reheated.

  17. 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.

  18. Quantification of the secondary flow in a radial coupled centrifugal blood pump based on particle tracking velocimetry.

    PubMed

    Watanabe, Nobuo; Masuda, Takaya; Iida, Tomoya; Kataoka, Hiroyuki; Fujimoto, Tetsuo; Takatani, Setsuo

    2005-01-01

    Secondary flow in the centrifugal blood pump helps to enhance the washout effect and to minimize thrombus formation. On the other hand, it has an adverse effect on pump efficiency. Excessive secondary flow may induce hemolytic effects. Understanding the secondary flow is thus important to the design of a compact, efficient, biocompatible blood pump. This study examined the secondary flow in a radial coupled centrifugal blood pump based on a simple particle tracking velocimetry (PTV) technique. A radial magnetically coupled centrifugal blood pump has a bell-shaped narrow clearance between the impeller inner radius and the pump casing. In order to vary the flow levels through the clearance area, clearance widths of 0.25 mm and 0.50 mm and impeller washout holes with diameters of 0 mm, 2.5 mm, and 4 mm were prepared. A high-speed video camera (2000 frames per second) was used to capture the particle images from which radial flow components were derived. The flow in the space behind the impeller was assumed to be laminar and Couette type. The larger the inner clearance or diameter of washout hole, the greater was the secondary flow rate. Without washout holes, the flow behind the impeller resulted in convection. The radial flow through the washout holes of the impeller was conserved in the radial as well as in the axial direction behind the impeller. The increase in the secondary flow reduced the net pump efficiency. Simple PTV was successful in quantifying the flow in the space behind the impeller. The results verified the hypothesis that the flow behind the impeller was theoretically Couette along the circumferential direction. The convection flow observed behind the impeller agreed with the reports of other researchers. Simple PTV was effective in understanding the fluid dynamics to help improve the compact, efficient, and biocompatible centrifugal blood pump for safe clinical applications.

  19. 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.

  20. 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.

  1. 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.

  2. Radially dependent large-scale dynamos in global cylindrical shear flows and the local cartesian limit

    NASA Astrophysics Data System (ADS)

    Ebrahimi, F.; Blackman, E. G.

    2016-06-01

    For cylindrical differentially rotating plasmas, we study large-scale magnetic field generation from finite amplitude non-axisymmetric perturbations by comparing numerical simulations with quasi-linear analytic theory. When initiated with a vertical magnetic field of either zero or finite net flux, our global cylindrical simulations exhibit the magnetorotational instability (MRI) and large-scale dynamo growth of radially alternating mean fields, averaged over height and azimuth. This dynamo growth is explained by our analytic calculations of a non-axisymmetric fluctuation-induced electromotive force that is sustained by azimuthal shear of the fluctuating fields. The standard `Ω effect' (shear of the mean field by differential rotation) is unimportant. For the MRI case, we express the large-scale dynamo field as a function of differential rotation. The resulting radially alternating large-scale fields may have implications for angular momentum transport in discs and corona. To connect with previous work on large-scale dynamos with local linear shear and identify the minimum conditions needed for large-scale field growth, we also solve our equations in local Cartesian coordinates. We find that large-scale dynamo growth in a linear shear flow without rotation can be sustained by shear plus non-axisymmetric fluctuations - even if not helical, a seemingly previously unidentified distinction. The linear shear flow dynamo emerges as a more restricted version of our more general new global cylindrical calculations.

  3. Extracting kinetic freeze-out temperature and radial flow velocity from an improved Tsallis distribution

    NASA Astrophysics Data System (ADS)

    Lao, Hai-Ling; Liu, Fu-Hu; Lacey, Roy A.

    2017-03-01

    We analyze the transverse-momentum (pT) spectra of identified particles (π^{±}, K^{±}, p, and \\bar{p}) produced in gold-gold (Au-Au) and lead-lead (Pb-Pb) collisions over a √{s_{NN}} (center-of-mass energy per nucleon pair) range from 14.5 GeV (one of the Relativistic Heavy Ion Collider (RHIC) energies) to 2.76 TeV (one of the Large Hadron Collider (LHC) energies). For the spectra with a narrow pT range, an improved Tsallis distribution which is in fact the Tsallis distribution with radial flow is used. For the spectra with a wide pT range, a superposition of the improved Tsallis distribution and an inverse power law is used. Both the extracted kinetic freeze-out temperature (T0) and radial flow velocity (βT) increase with the increase of √{s_{NN}}, which indicates a higher excitation and larger expansion of the interesting system at the LHC. Both the values of T0 and βT in central collisions are slightly larger than those in peripheral collisions, and they are independent of isospin and slightly dependent on mass.

  4. Mapping the fluid flow and shear near the core surface using the radial and horizontal components of the magnetic field

    NASA Technical Reports Server (NTRS)

    Jackson, Andrew; Bloxham, Jeremy

    1991-01-01

    The problem of calculating the temporal evolution of both the radial and horizontal poloidal components of a field, given an initial field and the flow and shear, is first considered. Attention is then given to the inverse problem of determining the flow and shear, given an initial field and its temporal evolution. The nonuniqueness inherent in such inversions is discussed, and it is shown that part of the nonuniqueness in the shear is closely related to that in the flow derived from just the radial induction equation.

  5. On the flow between a rotating and a coaxial fixed disc - Numerical validation of the radial similarity hypothesis

    NASA Astrophysics Data System (ADS)

    Oliveira, L. A.; Pecheux, J.; Restivo, A. O.

    1991-06-01

    The rotating flow between coaxial disks in a radially confined geometry is studied by numerical integration of the full Navier-Stokes equations. The results indicate that both Batchelor's and Stewartson's flow structures can be observed near the axis of rotation, depending on what conditions are set at the peripheral boundary.

  6. 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)

  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. Porcine circovirus (PCV) removal by Q sepharose fast flow chromatography.

    PubMed

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

  9. 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

  10. Accurate evaluation of viscoelasticity of radial artery wall during flow-mediated dilation in ultrasound measurement

    NASA Astrophysics Data System (ADS)

    Sakai, Yasumasa; Taki, Hirofumi; Kanai, Hiroshi

    2016-07-01

    In our previous study, the viscoelasticity of the radial artery wall was estimated to diagnose endothelial dysfunction using a high-frequency (22 MHz) ultrasound device. In the present study, we employed a commercial ultrasound device (7.5 MHz) and estimated the viscoelasticity using arterial pressure and diameter, both of which were measured at the same position. In a phantom experiment, the proposed method successfully estimated the elasticity and viscosity of the phantom with errors of 1.8 and 30.3%, respectively. In an in vivo measurement, the transient change in the viscoelasticity was measured for three healthy subjects during flow-mediated dilation (FMD). The proposed method revealed the softening of the arterial wall originating from the FMD reaction within 100 s after avascularization. These results indicate the high performance of the proposed method in evaluating vascular endothelial function just after avascularization, where the function is difficult to be estimated by a conventional FMD measurement.

  11. 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.

  12. Comparisons between seismic Earth structures and mantle flow models based on radial correlation functions

    SciTech Connect

    Jordan, T.H.; Puster, P. ); Glatzmaier, G.A. ); Tackley, P.J. )

    1993-09-10

    Three-dimensional numerical simulations were conducted of mantle convection in which flow through the transition zone is impeded by either a strong chemical change or an endothermic phase change. The temperature fields obtained from these models display a well defined minimum in the vertical correlation length at or near the radius where the barrier is imposed, even when the fields were filtered to low angular and radial resolutions. However, evidence for such a feature is lacking in the shear-velocity models derived by seismic tomography. This comparison suggests that any stratification induced by phase or chemical changes across the mid-mantle transition zone has a relatively small effect on the large-scale circulation of mantle material.

  13. Comparisons between seismic Earth structures and mantle flow models based on radial correlation functions.

    PubMed

    Jordan, T H; Puster, P; Glatzmaier, G A; Tackley, P J

    1993-09-10

    Three-dimensional numerical simulations were conducted of mantle convection in which flow through the transition zone is impeded by either a strong chemical change or an endothermic phase change. The temperature fields obtained from these models display a well-defined minimum in the vertical correlation length at or near the radius where the barrier is imposed, even when the fields were filtered to low angular and radial resolutions. However, evidence for such a feature is lacking in the shear-velocity models derived by seismic tomography. This comparison suggests that any stratification induced by phase or chemical changes across the mid-mantle transition zone has a relatively small effect on the large-scale circulation of mantle material.

  14. 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.

  15. Perception of heading speed from radial flow depends on visual field

    NASA Astrophysics Data System (ADS)

    Segawa, Kaori; Ujike, Hiroyasu; Okajima, Katsunori; Saida, Shinya

    2012-07-01

    We investigated the effects that the visual field has on the perception of heading speed. The stimulus was a radial flow pattern simulating a translational motion through a cylindrical tunnel. Observers evaluated the perception of heading speed by using a temporal two-alternative forced choice (2AFC) staircase method. In the first experiment, we manipulated the stimulus area by cutting the visual field along the longitudinal direction. The results showed that the perceived heading speed increases with the stimulus area. In the second experiment, we manipulated both the stimulus area and the eccentricity by cutting the visual field along the longitudinal direction. The results showed that the perception of heading speed increases when the stimulus occupies a large portion of the peripheral visual field. These findings suggest that the effect of eccentricity is a consequence of an incorrect translation of two-dimensional visual information into three-dimensional scaling.

  16. 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

  17. Influence of punch face angle and reduction on flow mode in backward and combined radial backward extrusion process

    NASA Astrophysics Data System (ADS)

    Noh, Jeong-hoon; Hwang, Beong Bok; Lee, Ho Yong

    2015-11-01

    This paper is concerned with the analysis on the flow mode which determines lubrication limit such as stiction onto or sliding over punch face. The main goal of this study is to examine the influence of geometrical parameters such as punch face angle, reduction in area, and the gap height in radial direction in backward and combined radial-backward extrusion process on the flow mode and surface stresses such as sliding velocity, sliding distance and surface expansion. Annealed steel 17Cr3 was selected as a model material, a rigid-plastic material, for simulation, which was conducted using a commercially available FEA tool, Deform 2-D, programmed in a rigid plasticity theory. Change of flow mode during deformation was also investigated to find under which conditions of process parameter adopted the flow mode changes from stiction to transition or transition to sliding. In this paper, sliding velocities were quantitatively analyzed to determine the flow mode.

  18. The hydraulic jump in radially spreading flow: A new model and new experimental data

    NASA Astrophysics Data System (ADS)

    Blackford, B. L.

    1996-02-01

    A new model for the hydraulic jump in radially spreading flow is presented. The equation of motion for a liquid annulus spreading out under the influence of hydrostatic pressure gradient and Frictional drag is developed. The resulting nonlinear differential equation for the liquid depth, h(r), is solved by computer simulation. The jump is assumed to begin when the laminar flow is engulfed by the underlying boundary layer liquid, as suggested recently in the literature. This complicated mixing process is crudely modeled by a drag term which slows the flow and initiates a positive feedback mechanism culminating at a new critical depth, beyond which the depth increases asymptotically to a final value. The model predicts a new relationship between the laminar flow depth just before the jump and the final depth. An experimental apparatus was built to make detailed measurements of the depth h(r), both in the region before the jump and beyond the jump. The theoretical predictions were compared to the experimental data, and gave surprisingly good agreement by suitable adjustment of the two parameters k and C of the model. The parameter k determines the growth rate of the boundary layer thickness, and C determines the drag force. The results suggest that the usual textbook assumption of zero momentum loss across the jump is not appropriate for this type of hydraulic jump. The case of a hydraulic jump in the absence of gravity is considered also and a much different behavior is predicted, which could be tested by experiment in a microgravity environment.

  19. 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

  20. Experimental study of convective heat transfer of compressed air flow in radially rotating ducts

    SciTech Connect

    Hwang, G.J,; Tzeng, S.C.; Mao, C.P.

    1999-07-01

    The convective heat transfer of pressurized air flow in radially rotating serpentine channel is investigated experimentally in the present study. The main governing parameters are the Prandtl number, the Reynolds number for forced convection, the rotation number for the Coriolis force induced cross stream secondary flow and the Grashof number for natural convection. To simulate the operation conditions of a real gas turbine, the present study kept the parameters in the test rig approximately the same as those in a real engine. The air in the present serpentine channel was pressurized to increase the air density for making up the low rotational speed in the experiment. Before entering the rotating ducts, the air was also cooled to gain a high density ratio of approximately 1/3 in the ducts. This high density ratio will give a similar order of magnitude of Grashof number in a real operation condition. The local heat transfer rate on the four channel walls are present and compared with that in existing literature.

  1. Radial pressure profiles in a cold‐flow gas‐solid vortex reactor

    PubMed Central

    Pantzali, Maria N.; Kovacevic, Jelena Z.; Marin, Guy B.; Shtern, Vladimir N.

    2015-01-01

    A unique normalized radial pressure profile characterizes the bed of a gas‐solid vortex reactor over a range of particle densities and sizes, solid capacities, and gas flow rates: 950–1240 kg/m3, 1–2 mm, 2 kg to maximum solids capacity, and 0.4–0.8 Nm3/s (corresponding to gas injection velocities of 55–110 m/s), respectively. The combined momentum conservation equations of both gas and solid phases predict this pressure profile when accounting for the corresponding measured particle velocities. The pressure profiles for a given type of particles and a given solids loading but for different gas injection velocities merge into a single curve when normalizing the pressures with the pressure value downstream of the bed. The normalized—with respect to the overall pressure drop—pressure profiles for different gas injection velocities in particle‐free flow merge in a unique profile. © 2015 The Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers AIChE J, 61: 4114–4125, 2015 PMID:27667827

  2. 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.

    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.

  3. 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...

  4. 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 3•10-3 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 Péclet 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

  5. 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.

  6. Axisymmetric flow and heat transfer to modified second grade fluid over a radially stretching sheet

    NASA Astrophysics Data System (ADS)

    Khan, Masood; Rahman, Masood ur; Manzur, Mehwish

    In the present work, an analysis is made to the two-dimensional axisymmetric flow and heat transfer of a modified second grade fluid over an isothermal non-linear radially stretching sheet. The momentum and energy equations are modelled and the boundary layer equations are derived. The governing equations for velocity and temperature are turned down into a system of ordinary differential equations by invoking appropriate transformations which are then solved numerically via fourth and fifth order Runge-Kutta Fehlberg method. Moreover, the influence of the pertinent parameters namely the generalized second grade parameter, stretching parameter, the power-law index and the generalized Prandtl number is graphically portrayed. It is inferred that the generalized second grade parameter uplifted the momentum boundary layer while lessened the thermal boundary layer. Furthermore, the impact of stretching parameter is more pronounced for the second grade fluid (m = 0) in contrast with the power-law fluid (k = 0). For some special cases, comparisons are made with previously reported results and an excellent agreement is established.

  7. 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-Väisälä 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

  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; Schädel, Matthias; Ooe, Kazuhiro; Kasamatsu, Yoshitaka; Shinohara, Atsushi; Haba, Hiromitsu; Even, Julia

    2013-11-04

    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.

  9. 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 ...

  10. 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.

  11. Anatomical features that facilitate radial flow across growth rings and from xylem to cambium in Cryptomeria japonica

    PubMed Central

    Kitin, Peter; Fujii, Tomoyuki; Abe, Hisashi; Takata, Katsuhiko

    2009-01-01

    Background and Aims Although the lateral movement of water and gas in tree stems is an important issue for understanding tree physiology, as well as for the development of wood preservation technologies, little is known about the vascular pathways for radial flow. The aim of the current study was to understand the occurrence and the structure of anatomical features of sugi (Cryptomeria japonica) wood including the tracheid networks, and area fractions of intertracheary pits, tangential walls of ray cells and radial intercellular spaces that may be related to the radial permeability (conductivity) of the xylem. Methods Wood structure was investigated by light microscopy and scanning electron microscopy of traditional wood anatomical preparations and by a new method of exposed tangential faces of growth-ring boundaries. Key Results Radial wall pitting and radial grain in earlywood and tangential wall pitting in latewood provide a direct connection between subsequent tangential layers of tracheids. Bordered pit pairs occur frequently between earlywood and latewood tracheids on both sides of a growth-ring boundary. In the tangential face of the xylem at the interface with the cambium, the area fraction of intertracheary pit membranes is similar to that of rays (2·8 % and 2·9 %, respectively). The intercellular spaces of rays are continuous across growth-ring boundaries. In the samples, the mean cross-sectional area of individual radial intercellular spaces was 1·2 µm2 and their total volume was 0·06 % of that of the xylem and 2·07 % of the volume of rays. Conclusions A tracheid network can provide lateral apoplastic transport of substances in the secondary xylem of sugi. The intertracheid pits in growth-ring boundaries can be considered an important pathway, distinct from that of the rays, for transport of water across growth rings and from xylem to cambium. PMID:19258338

  12. Sound fields in a lined annular flow duct with lined radial splitters

    NASA Technical Reports Server (NTRS)

    Mungur, P.; Kapur, A.

    1974-01-01

    High attenuation in the inlet duct of fan-jet engines is limited mainly because of two factors: the duct length is short and the frequency is high giving rise to a large duct width to wavelength ratio. Lined radial splitters may be installed. In this configuration not only is the absorbing surface area increased, the acoustic propagation properties in each of the segmented ducts are different to those in a cylindrical or annular duct without radial splitters. Such differences in properties can be used to advantage for mismatching the acoustic source. A lower order spinning mode must propagate as a higher order (integral or fractional) spinning mode. Cut-off phenomena may also be used to advantage. A theoretical modal analysis is made of the sound inside one segment of the annular duct with lined radial splitters.

  13. Impact behavior of a high viscosity magnetorheological fluid-based energy absorber with a radial flow mode

    NASA Astrophysics Data System (ADS)

    Fu, Benyuan; Liao, Changrong; Li, Zhuqiang; Xie, Lei; Zhang, Peng; Jian, Xiaochun

    2017-02-01

    High viscosity linear polysiloxane magnetorheological fluid (HVLP MRF) was demonstrated with excellent suspension stability. Such material is suitable for application in the magnetorheological energy absorbers (MREAs) under axial impact loading conditions. On this basis, a new energy absorber incorporating a radial valve with high magnetic field utilization and a corrugated tube is proposed. In energy absorption applications where the MREA is rarely if ever used, our MREA takes the ultra-stable HVLP MRF as controlled medium in order for a long-term stability. For MREA performing at very high shear rates where the minor losses are important contributing factors to damping, a nonlinear analytical model, based on the Herschel-Bulkley flow model (HB model), is developed taking into account the effects of minor losses (called HBM model). The HB model parameters are determined by rheological experiments with a commercial shear rheometer. Then, continuity equation and governing differential equation of the HVLP MRF in radial flow are established. Based on the HB model, the expressions of radial velocity distribution are deduced. The influences of minor losses on pressure drop are analyzed with mean fluid velocities. Further, mechanical behavior of the corrugated tube is investigated via drop test. In order to verify the theoretical methodology, a MREA is fabricated and tested using a high-speed drop tower facility with a 600 kg mass at different drop heights and in various magnetic fields. The experiment results show that the HBM model is capable of well predicting the impact behavior of the proposed MREA.

  14. 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.

  15. 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.

  16. 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.

  17. 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 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.

  18. A mathematical model linking tree sap flow dynamics to daily stem diameter fluctuations and radial stem growth.

    PubMed

    Steppe, Kathy; De Pauw, Dirk J W; Lemeur, Raoul; Vanrolleghem, Peter A

    2006-03-01

    To date, models for simulating sap flow dynamics in individual trees with a direct link to stem diameter variation include only the diameter fluctuation driven by a change in stem water storage. This paper reports results obtained with a comprehensive flow and storage model using whole-tree leaf transpiration as the only input variable. The model includes radial stem growth based on Lockhart's equation for irreversible cell expansion. It was demonstrated that including growth is essential to obtaining good simulation results. To model sap flow dynamics, capacitance of storage tissues was assumed either constant (i.e., electrical analogue approach) or variable and dependent on the water content of the respective storage tissue (i.e., hydraulic system approach). These approaches resulted in different shapes for the desorption curve used to calculate the capacitance of storage tissues. Comparison of these methods allowed detection of specific differences in model simulation of sap flow at the stem base (F(stem)) and stem diameter variation (D). Sensitivity analysis was performed to select a limited subset of identifiable parameters driving most of the variability in model predictions of F(stem) and D Both the electrical analogue and the hydraulic system approach for the flow and storage model were successfully calibrated and validated for the case of a young beech tree (Fagus sylvatica L.). Use of an objective model selection criterion revealed that the flow and storage model based on the electrical analogue approach yielded better predictions.

  19. 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.}

  20. Adhesion of nonmotile Pseudomonas aeruginosa on "soft" polyelectrolyte layer in a radial stagnation point flow system: measurements and model predictions.

    PubMed

    de Kerchove, Alexis J; Weroński, Paweł; Elimelech, Menachem

    2007-11-20

    Prediction of bacterial deposition rates onto substrates in natural aquatic systems is quite challenging because of the inherent complexity of such systems. In this study, we compare experimental deposition kinetics of nonmotile bacteria (Pseudomonas aeruginosa) on an alginate-coated substrate in a radial stagnation point flow (RSPF) system to predictions based on DLVO theory. The "softness" of the surface layer of the bacteria and alginate-coated substrate was considered in the calculations of their electrokinetic surface properties, and the relevance of both the classical zeta potential and the outer surface potential as surrogates for surface potential was investigated. Independent of the used electrical potentials, we showed that significant discrepancies exist between theory and experiments. Analysis of microscopic images in the RSPF system has demonstrated, for the first time, that irreversible deposition of particles or cells entrapped in the secondary energy minimum can occur on the alginate layer, despite the hydrodynamic forces resulting from the radial flow in the RSPF system. It is suggested that polymeric structures associated with the surface of the particle/cell and the alginate-coated substrate are responsible for the transition between the secondary minimum and primary energy well. This mode of deposition is likely to be important in the deposition of microorganisms in complex aquatic systems.

  1. A radial flow microfluidic device for ultra-high-throughput affinity-based isolation of circulating tumor cells.

    PubMed

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

    2014-12-10

    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, a high throughput microfluidic technology, the OncoBean Chip, is reported. It employs 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 is validated with cancer cell lines H1650 and MCF7, achieving a mean efficiency >80% at a throughput of 10 mL h(-1) in contrast to a flow rate of 1 mL h(-1) standardly reported with other microfluidic devices. Cells are recovered with a viability rate of 93% at these high speeds, increasing the ability to use captured CTCs for downstream analysis. Broad clinical application is demonstrated using comparable flow rates from blood specimens obtained from breast, pancreatic, and lung cancer patients. Comparable CTC numbers are recovered in all the samples at the two flow rates, demonstrating the ability of the technology to perform at high throughputs.

  2. 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

  3. Radial Hele-Shaw flow with suction: Fully nonlinear pattern formation

    NASA Astrophysics Data System (ADS)

    Chen, Ching-Yao; Huang, Yu-Sheng; Miranda, José A.

    2014-05-01

    We study the development of intricate, fully nonlinear immiscible interfacial patterns in the suction-driven radial Hele-Shaw problem. The complex-shaped, contracting fluid-fluid interface arises when an initially circular blob of more viscous fluid, surrounded by less viscous one, is drawn into an eccentric point sink. We present sophisticated numerical simulations, based on a diffuse interface model, that capture the most prominent interfacial features revealed by existing experimental studies of the problem. The response of the system to changes in the capillary number is investigated, accurately revealing the occurrence of finger competition phenomena, and correctly describing the velocity behavior of both inward- and outward-pointing fingers. For the large-capillary-number regime, a set of complex interfacial features (finger merging, shielding, and pinch-off) whose experimental realization is still not available, are predicted.

  4. Large eddy simulations of the flow field of a radially lobed nozzle

    NASA Astrophysics Data System (ADS)

    Amini, Noushin; Sekaran, Aarthi

    2016-11-01

    Lobed nozzles have been a studied over the past couple of decades due to their enhanced mixing capabilities. Despite experimental (Hu et al., 2000) and numerical studies (Cooper et al., 2005), the nature of the jet is yet to be fully understood. This numerical study intends to carry out a thorough analysis of the flow field within and downstream of a six lobed nozzle. The study aims to confirm vortical interaction mechanisms and establish the role of hydrodynamic instabilities in the mixing process. This was inspired by a prior study by the authors wherein the same flow was studied using hot-wire anemometry. Although this helped obtain a qualitative idea of the flow, the 2D data was incapable of visualizing streamwise structures and the flow within the nozzle. Previous numerical simulations have used RANS and to simulate a single lobe of the nozzle; these results show some deficiencies in predicting the potential core length. Previous simulations done by authors indicated that RANS models qualitatively capture the flow structures but do not accurately represent the values of key parameters in the flow field. The present study aims to perform a 3D LES study of the flow field within and downstream of the nozzle to follow the ensuing free jet and thus analyze various mechanisms.

  5. Cold Flow Diluent Mixing Study Using Radial High Density Ratio Jets into a Circular Freestream

    DTIC Science & Technology

    2010-07-01

    CAD) solid models. From the CAD model, computational grids are generated for the CFD simulations using Gridgen v.15. Appropriate flow modeling...release, Distribution is unlimited 4 Figure 2: Geometry and Mesh Boundaries in Water Jet Simulations Grid Generation and Flow Model GRIDGEN v.15...generated using GRIDGEN v.15. Figure 4 shows the computational domain for the dual-jet configuration. The modeled domain contains 1.3 to 1.8

  6. Swirling Flow Computation at the Trailing Edge of Radial-Axial Hydraulic Turbines

    NASA Astrophysics Data System (ADS)

    Susan-Resiga, Romeo; Muntean, Sebastian; Popescu, Constantin

    2016-11-01

    Modern hydraulic turbines require optimized runners within a range of operating points with respect to minimum weighted average draft tube losses and/or flow instabilities. Tractable optimization methodologies must include realistic estimations of the swirling flow exiting the runner and further ingested by the draft tube, prior to runner design. The paper presents a new mathematical model and the associated numerical algorithm for computing the swirling flow at the trailing edge of Francis turbine runner, operated at arbitrary discharge. The general turbomachinery throughflow theory is particularized for an arbitrary hub-to-shroud line in the meridian half-plane and the resulting boundary value problem is solved with the finite element method. The results obtained with the present model are validated against full 3D runner flow computations within a range of discharge value. The mathematical model incorporates the full information for the relative flow direction, as well as the curvatures of the hub-to-shroud line and meridian streamlines, respectively. It is shown that the flow direction can be frozen within a range of operating points in the neighborhood of the best efficiency regime.

  7. 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.

  8. Experimental Study and Theoretical Analysis of the Rotating Stall in a Vaneless Diffuser of Radial Flow Pump

    NASA Astrophysics Data System (ADS)

    Heng, Y. G.; Dazin, A.; Ouarzazi, M. N.; Si, Q. R.

    2016-11-01

    This paper reports an experimental and theoretical study of rotating stall in a vaneless diffuser which is coupled with a radial impeller. The experiments were conducted at 22 flow rates for two rotating speed: 1200rpm and 1800rpm. The measurements have consisted of: i/ unsteady pressure measurements delivered by two microphones flush mounted on the vaneless diffuser, ii/ 9 steady pressure taps mounted in one radial line on the diffuser to measure the pressure recovery in the vaneless diffuser. The stability of each stall mode was also studied by a 2D linear analysis; and the theoretical prediction was compared to experimental observations. The capabilities and limits of such an approach to predict the development of rotating stall have been evaluated. A non-dimensional analysis of the pressure losses at outlet was conducted to evaluate the effect of the instability development on the performance of the diffuser. It has shown that the arising of rotating stall has a positive effect on the diffuser performance.

  9. A system for intravascular, radially orientation-independent electromagnetic flow- and diameter-sensing.

    PubMed

    Kolin, A

    1977-11-25

    The difficulty of optimally orienting an intravascular loop probe of an extracorporeal field electromagnetic flow meter is circumvented by uniting 2 mutually perpendicular loop sensors into a single flow-diameter probe. When one of the loops is unfavorably oriented in the magnetic field, the orientations of the other loop is more favorable. The most unfavorable case is a 45 degrees angle between the magnetic field and the planes of the loops, when the signal drops to 70.7% of the optimal value. By taking the square root of the sum of the squares of the 2 loop transducer signals, one obtains an output for flow and diameter measurements which is independent of the probe orientation. This operation can be accomplished electronically.

  10. Microwave signal amplification and Pierce instability on radial electron flows in cylindrical and spherical diodes

    SciTech Connect

    Gnavi, G.; Gratton, F.T. )

    1994-11-01

    Linear space charge perturbations of focused electron beams flowing between cylindrical and spherical electrodes on convergent or divergent trajectories are studied, and the amplification of high-frequency signals when the flow is modulated at one electrode is computed. It is shown that divergent beams give the largest amplification effect. The instability of electron beams drifting through grounded grids (Pierce instability in cylindrical or spherical diodes) is also considered. The instability threshold occurs at higher critical currents when the curvature of the electrodes is large. Results for planar electrodes are recovered in the limit of zero curvature devices. Spherical configurations have better signal amplification and stability properties than similar planar or cylindrical systems.

  11. 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.

  12. A three-dimensional Navier-Stokes stage analysis of the flow through a compact radial turbine

    NASA Technical Reports Server (NTRS)

    Heidmann, James D.

    1991-01-01

    A steady, three-dimensional Navier-Stokes average passage computer code is used to analyze the flow through a compact radial turbine stage. The code is based upon the average passage set of equations for turbomachinery, whereby the flow fields for all passages in a given blade row are assumed to be identical while retaining their three-dimensionality. A stage solution is achieved by alternating between stator and rotor calculations, while coupling the two solutions by means of a set of axisymmetric body forces which model the absent blade row. Results from the stage calculation are compared with experimental data and with results from an isolated rotor solution having axisymmetric inlet flow quantities upstream of the vacated stator space. Although the mass-averaged loss through the rotor is comparable for both solutions, the details of the loss distribution differ due to stator effects. The stage calculation predicts smaller spanwise variations in efficiency, in closer agreement with the data. The results of the study indicate that stage analyses hold promise for improved prediction of loss mechanisms in multi-blade row turbomachinery, which could lead to improved designs through the reduction of these losses.

  13. A three-dimensional Navier-Stokes stage analysis of the flow through a compact radial turbine

    NASA Technical Reports Server (NTRS)

    Heidmann, James D.

    1991-01-01

    A steady, three dimensional Navier-Stokes average passage computer code is used to analyze the flow through a compact radial turbine stage. The code is based upon the average passage set of equations for turbomachinery, whereby the flow fields for all passages in a given blade row are assumed to be identical while retaining their three-dimensionality. A stage solution is achieved by alternating between stator and rotor calculations, while coupling the two solutions by means of a set of axisymmetric body forces which model the absent blade row. Results from the stage calculation are compared with experimental data and with results from an isolated rotor solution having axisymmetric inlet flow quantities upstream of the vacated stator space. Although the mass-averaged loss through the rotor is comparable for both solutions, the details of the loss distribution differ due to stator effects. The stage calculation predicts smaller spanwise variations in efficiency, in closer agreement with the data. The results of the study indicate that stage analyses hold promise for improved prediction of loss mechanisms in multi-blade row turbomachinery, which could lead to improved designs through the reduction of these losses.

  14. Performance simulation of a radial flow type impeller of centrifugal pumps using CFD

    NASA Astrophysics Data System (ADS)

    López, R.; Vaca, M.; Terres, H.; Lizardi, A.; Chávez, S.; García., M.

    2017-01-01

    The numerical simulation of a centrifugal impeller that had previously been designed and manufactured is presented in this paper. The following operating conditions were determined: 0.50 m3/min volumetric flow at a load of 25 m, velocity of rotation of 1750 rpm, and specific velocity of 0. 27. The ANSYS CFX 14.5 software with the k-ε turbulence model was used for simulation with appropriate boundary conditions. The distributions of velocities in the flow field in addition to the distribution of pressures on the entire impeller were obtained. The simulation showed no negative values for the pressure at the entrance of the impeller. The curve of hydrodynamic behaviour of the impeller, which contains the point of operation in which the pump will work was also developed.

  15. Prediction of heat transfer to a thin liquid film in plane and radially spreading flows

    SciTech Connect

    Rahman, M.M.; Faghri, A.; Hankey, W.L. ); Swanson, T.D. )

    1990-08-01

    The numerical solution of a thin film flow is difficult since the free surface geometry changes along the path of the flow, is unknown ahead of time, and cannot be fitted in a regular Cartesian or cylindrical coordinate system. Therefore, most theoretical studies in this area were related to the development of approximate analytical models (Faghri and Seban, 1981; Chaudhury, 1964). The finite-difference solution was attempted only for a falling film (Faghri and Payvar, 1979) where the film thickness could be approximated to be uniform. Recently, Rahman et al. (1990a) have developed a finite-difference solution method applicable for the fluid mechanics of thin film flows under zero and normal gravity. A body-fitted coordinate system was used where the free surface was approximated by a curve and iterated for the best possible solution. The present study is intended to incorporate the energy equation in the solution algorithm of Rahman et al. (1990a) to compute the heat transfer to a thin film in the presence or absence of gravity. In addition to the enhancement of the knowledge of thin film heat transfer, the results of the present study may be directly applicable to the design of space-based cooling systems.

  16. Numerical simulation of the flow field from a radially lobed nozzle and validation via HWA

    NASA Astrophysics Data System (ADS)

    Amini, Noushin; Sekaran, Aarthi

    2014-11-01

    With a constant need for higher performance and efficiency in engineering (particularly aerospace) applications, lobed nozzles have experienced a regained interest in the recent past, owing to their superior mixing capabilities. Although previous experimental studies (Hu et al. 1999, Hu et al. 2008) have analyzed the flow field from lobed nozzles and made conjectures about the physics and flow mechanisms involved, the absence of a ``complete'' 3D dataset elicits unanswered questions. The present numerical study is intended as a complement to an existing experimental (single component hot wire anemometry) investigation, involving the analysis of the flow field downstream of a six lobed nozzle (N. Amini et al., 2012). A full 3D URANS simulation of the lobed nozzle is carried out, initially validated with experimental data, and then used to examine the stream-wise vortices and obtain a visual corroboration of the structure formation and breakup mechanism as described earlier (Hu et al., 2008). Further, the study takes a close look at the nature of the instabilities which trigger and enhance the mixing process in lobed nozzles in order to determine the precise role of the lobes and eventually obtain more effective mixing in industrial applications.

  17. [Radial variation and time lag of sap flow of Populus gansuensis in Minqin Oasis, Northwest].

    PubMed

    Dang, Hong-Zhong; Yang, Wen-Bin; Li, Wei; Zhang, You-Yan; Li, Chang-Long

    2014-09-01

    Sap flow of tree trunk is very important to reflect the dynamics of physiological activities, as well as to estimate the water consumption of individual plant. In the present study, we used the thermal dissipation technique to monitor the sap flow velocity (J) at four depth loci (i. e. 2 cm, 3 cm, 5 cm, 8 cm) of three Populus gansuensis trees (30 year-old) in Minqin Oasis for two consecutive growing seasons. The results showed that there were significant differences among J values at four depth loci under tree trunk cambium. J value at the 3 cm depth locus (J3) of the tree trunk was the highest, and then in sequences, were 2 cm, 5 cm and 8 cm depth loci (J2, J5 and J8). J value (J3) on typical sunny days in June with the highest atmospheric potential evapotranspiration (ET0) was up to 28.53 g · cm(-2) · h(-1), which was 1.42, 2.74 and 4.4 times of J2, J5 and J8, respectively. In the process of diurnal variation of sap flow velocity, the peak value time of J at the four depth loci of the tree trunk was different, but the differences among them were within 20 min. Furthermore, the peak value time of sap flow velocity was very different to that of solar radiation (Rs) and air vapour pressure deficit (VPD). The time lag between J and Rs was from 55 to 88 min on typical sunny days during the main growing seasons (from June to August), and, positively related to the depth of the locus under tree trunk cambium, while the time lag between J and VPD reached 60-96 min, and was negatively related to the depth of the locus. The seasonal variation patterns of J were consistent with ET0. With the increase of tree physiological activities, there was a trend that the major water transportation layer extended to the interior sapwood. The most important meteorological factor was the solar radiation, which primarily drove sap flow at different depths of tree trunk. However, the secondary factor changed along with the depth, and VPD became increasingly important with increasing the

  18. 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.

  19. 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.

  20. Large Eddy Simulations and an Analysis of the Flow Field of a Radially Lobed Nozzle

    NASA Astrophysics Data System (ADS)

    Amini, Noushin; Sekaran, Aarthi

    2015-11-01

    Lobed nozzles have been a subject of regained interest over the past couple of decades owing to their established mixing capabilities. Despite experimental (Hu et al., 1999 and Hu et al., 2008) and limited numerical studies (Boulenouar et al. 2011 and Cooper et al., 2005), the exact nature of the jet ensuing from this nozzle is yet to be completely understood. The present numerical study is intended to complement prior experimental investigation, involving the analysis of the flow field downstream of a six lobed nozzle (Amini et al., 2012). Preliminary results (presented at DFD 2014, Amin and Sekaran), which involved three dimensional simulations of the full domain via URANS and Large Eddy Simulations (LES) were used to assess the domain extents and simulation technique. Based on these results it was seen that LES were able to capture the region of interest satisfactorily and a qualitative corroboration with previous studies was obtained. The study is thus extended to analyzing the flow originating from within the nozzle, following it downstream in order to confirm the vortical interaction mechanisms inside the lobed nozzle.

  1. Optimal design of high damping force engine mount featuring MR valve structure with both annular and radial flow paths

    NASA Astrophysics Data System (ADS)

    Nguyen, Q. H.; Choi, S. B.; Lee, Y. S.; Han, M. S.

    2013-11-01

    This paper focuses on the optimal design of a compact and high damping force engine mount featuring magnetorheological fluid (MRF). In the mount, a MR valve structure with both annular and radial flows is employed to generate a high damping force. First, the configuration and working principle of the proposed MR mount is introduced. The MRF flows in the mount are then analyzed and the governing equations of the MR mount are derived based on the Bingham plastic behavior of the MRF. An optimal design of the MR mount is then performed to find the optimal structure of the MR valve to generate a maximum damping force with certain design constraints. In addition, the gap size of MRF ducts is empirically chosen considering the ‘lockup’ problem of the mount at high frequency. Performance of the optimized MR mount is then evaluated based on finite element analysis and discussions on performance results of the optimized MR mount are given. The effectiveness of the proposed MR engine mount is demonstrated via computer simulation by presenting damping force and power consumption.

  2. Radial, mixed and axial-flow pumps: Size estimation and specification, amendment A

    NASA Astrophysics Data System (ADS)

    1980-11-01

    This Data Item is available as part of the ESDU Sub-series on Fluid Mechanics Internal Flow. Performance estimates for a wide range of rotodynamic pumps are provided in order to anticipate the salient features of a suitable standard pump. This information which would otherwise only be available from a bulky collection of manufacturers' catalogs is complemented by a methodical procedure to pinpoint the most suitable pump configuration. Charts giving rapid estimates of size and efficiency (with formulae to allow easy programming for calculators or computers) are given together with approximate correlations of suction and discharge flange sizes, and data showing the effects that liquids of high viscosity have on pump performance. The information is supported by a comprehensive example which is backed up by numerous cross references to ESDU 80030 which provides a general introduction to pump performance considerations.

  3. Numerical study of cavitation and pinning effects due to gas injection through a bed of particles: application to a radial-flow moving-bed reactor

    NASA Astrophysics Data System (ADS)

    Vinay, Guillaume; Vasquez, Felaurys; Richard, Florence; Applied Mechanics Team

    2016-11-01

    In the petroleum and chemical industries, radial-flow moving-bed reactors are used to carry out chemical reactions such as catalytic reforming. Radial-flow reactors provide high capacity without increased pressure drop or greatly increased vessel dimensions. This is done by holding the catalyst in a basket forming an annular bed, and causing the gas to flow radially between the outer annulus and the central tube. Catalyst enter the top of the reactor, move through the vessel by gravity to the bottom where it is removed and then regenerated. Within the catalytic bed, the combined effects of particles motion and radial injection of the gas may lead to cavitation and pinning phenomenon that may clearly damage the reactor. We study both cavitation and pinning effects using an in-house numerical software, named PeliGRIFF (www.peligriff.com/), designed to simulate particulate flows at different scales; from the particle scale, where fluid/particle interactions are directly solved, to the particles suspension scale where the fluid/solid interactions are modeled. In the past, theoretical and experimental studies have already been conducted in order to understand the way cavitation and pinning occur. Here, we performed simulations involving a few thousands of particles aiming at reproducing experimental experiments. We will present comparisons between our numerical results and experimental results in terms of pressure drop, velocity, porosity.

  4. Redundant Vasodilator Pathways Underlying Radial Artery Flow-Mediated Dilation Are Preserved in Healthy Aging

    PubMed Central

    Ballard, Kevin D.; Tschakovsky, Michael E.; Zaleski, Amanda L.; Polk, Donna M.; Thompson, Paul D.; Kiernan, Francis J.; Parker, Beth A.

    2014-01-01

    Background. Blocking nitric oxide (NO) and vasodilator prostanoids (PN) does not consistently reduce flow-mediated dilation (FMD) in young adults. The impact of aging on the contribution of NO and PG to FMD is unknown. Methods. FMD was measured in older adults (n = 10, 65 ± 3 y) after arterial infusion of saline, N(G)-monomethyl-L-arginine (L-NMMA), and ketorolac + L-NMMA. Data were compared to published data in young adults. Results. L-NMMA reduced FMD in older adults (8.9 ± 3.6 to 5.9 ± 3.7%) although this was not statistically significant (P = 0.08) and did not differ (P = 0.74) from the reduction observed in young adults (10.0 ± 3.8 to 7.6 ± 4.7%; P = 0.03). Blocking PN did not affect FMD in young or older adults. In older adults, L-NMMA reduced (n = 6; range = 36–123% decrease), augmented (n = 3; 10–122% increase), or did not change FMD (n = 1; 0.4% increase). After PN blockade, FMD responses were reduced (n = 2), augmented (n = 6), or unaffected (n = 1). Conclusions. NO or PN blockade did not consistently reduce FMD in healthy older adults, suggesting the existence of redundant vasodilator phenotypes as observed previously in young adults. PMID:24963406

  5. Mid-section of a can-annular gas turbine engine with a radial air flow discharged from the compressor section

    DOEpatents

    Little, David A.; McQuiggan, Gerard; Wasdell, David L.

    2016-10-25

    A midframe portion (213) of a gas turbine engine (210) is presented, and includes a compressor section (212) configured to discharge an air flow (211) directed in a radial direction from an outlet of the compressor section (212). Additionally, the midframe portion (213) includes a manifold (214) to directly couple the air flow (211) from the compressor section (212) outlet to an inlet of a respective combustor head (218) of the midframe portion (213).

  6. Analysis of lignans in Magnoliae Flos by turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry.

    PubMed

    Zhou, Xuan; Chen, Cen; Ye, Xiaolan; Song, Fenyun; Fan, Guorong; Wu, Fuhai

    2016-04-01

    In this study, a method coupling turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry was developed for analyzing the lignans in Magnoliae Flos. By the online pretreatment of turbulent flow chromatography solid-phase extraction, the impurities removal and analytes concentration were automatically processed, and the lignans were separated rapidly and well. Seven lignans of Magnoliae Flos including epieudesmin, magnolin, 1-irioresinol-B-dimethyl ether, epi-magnolin, fargesin aschantin, and demethoxyaschantin were identified by comparing their retention behavior, UV spectra, and mass spectra with those of reference substances or literature data. The developed method was validated, and the good results showed that the method was not only automatic and rapid, but also accurate and reliable. The turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry method holds a high potential to become an effective method for the quality control of lignans in Magnoliae Flos and a useful tool for the analysis of other complex mixtures.

  7. Receptor-mediated cell attachment and detachment kinetics. II. Experimental model studies with the radial-flow detachment assay.

    PubMed Central

    Cozens-Roberts, C; Quinn, J A; Lauffenburger, D A

    1990-01-01

    Quantitative information regarding the kinetics of receptor-mediated cell adhesion to a ligand-coated surface are crucial for understanding the role of certain key parameters in many physiological and biotechnology-related processes. Here, we use the probabilistic attachment and detachment models developed in the preceding paper to interpret transient data from well-defined experiments. These data are obtained with a simple model cell system that consists of receptor-coated latex beads (prototype cells) and a Radial-Flow Detachment Assay (RFDA) using a ligand-coated glass disc. The receptors and ligands used in this work are complementary antibodies. The beads enable us to examine transient behavior with particles that possess fairly uniform properties that can be varied systematically, and the RFDA is designed for direct observation of adhesion to the ligand-coated glass surface over a range of shear stresses. Our experiments focus on the effects of surface shear stress, receptor density, and ligand density. These data provide a crucial test of the probabilistic framework. We show that these data can be explained with the probabilistic analyses, whereas they cannot be readily interpreted on the basis of a deterministic analysis. In addition, we examine transient data on cell adhesion reported from other assays, demonstrating the consistency of these data with the predictions of the probabilistic models. Images FIGURE 2 PMID:2174272

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

    SciTech Connect

    DeVol, T.A.; Fjeld, R.A.

    1995-10-01

    The use of ion chromatography (IC) for radiochemical separations is a well established technique. IC is commonly used in routine environmental monitoring applications as well as in specialized research applications. Typical usage involves the separation of a single radionuclide from the non-radioactive constituents. During the past decade, a limited amount of research has been conducted using automated IC systems in actinide separation applications (e.g.). More recently, separation procedures for common non-gamma emitting activation and fission products were developed utilizing a high performance liquid chromatography (HPLC) system. In addition, a separation procedure for six common actinides has been developed using a HPLC system. These latter systems used on-line flow-cell detectors for quantification of the radioactive constituents of the effluent stream.

  9. 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).

  10. Solute-solvent interactions in micellar electrokinetic chromatography: IV. Characterization of electroosmotic flow and micellar markers.

    PubMed

    Fuguet, Elisabet; Ràfols, Clara; Bosch, Elisabeth; Rosés, Martí

    2002-01-01

    A wide study of the compounds and procedures mostly used to determine the electroosmotic flow (EOF) and micelle elution times has been done in seven different micellar electrokinetic chromatography (MEKC) systems. These systems are formed from mixtures of an aqueous buffer with the surfactants sodium dodecyl sulfate, lithium dodecyl sulfate, lithium perfluorooctane sulfonate, sodium cholate, sodium deoxycholate, tetradecyltrimethylammonium bromide and hexadecyltrimethylammonium bromide. The solvation parameter model has been used to evaluate the usefulness of the compounds studied as EOF or micellar markers in each of the seven MEKC systems. It is demonstrated that methanol, acetonitrile and formamide are the best EOF markers, and that dodecanophenone is the best micellar marker.

  11. 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.

  12. Influence of growth phase on bacterial deposition: interaction mechanisms in packed-bed column and radial stagnation point flow systems.

    PubMed

    Walker, Sharon L; Redman, Jeremy A; Elimelech, Menachem

    2005-09-01

    The influence of bacterial growth stage on cell deposition kinetics has been examined using a mutant of Escherichia coli K12. Two experimental techniques--a packed-bed column and a radial stagnation point flow (RSPF) system--were employed to determine bacterial deposition rates onto quartz surfaces over a wide range of solution ionic strengths. Stationary-phase cells were found to be more adhesive than mid-exponential phase cells in both experimental systems. The divergence in deposition behavior was notably more pronounced in the RSPF than in the packed-bed system. For instance, in the RSPF system, the deposition rate of the stationary-phase cells at 0.03 M ionic strength was 14 times greater than that of the mid-exponential cells. The divergence in the packed-bed system was most significant at 0.01 M, where the deposition rate for the stationary-phase cells was nearly 4 times greater than for the mid-exponential cells. To explain the observed adhesion behavior, the stationary and mid-exponential bacterial cells were characterized for their size, surface charge density, electrophoretic mobility, viability, and hydrophobicity. On the basis of this analysis, it is suggested that the stationary cells have a more heterogeneous distribution of charged functional groups on the bacterial surface than the mid-exponential cells, which results in higher deposition kinetics. Furthermore, because the RSPF system enumerates only bacterial cells retained in primary minima, whereas the packed column captures mostly cells deposited in secondary minima, the difference in the stationary and mid-exponential cell deposition kinetics is much more pronounced in the RSPF system.

  13. Deposition of Cryptosporidium parvum oocysts on natural organic matter surfaces: microscopic evidence for secondary minimum deposition in a radial stagnation point flow cell.

    PubMed

    Liu, Yuanyuan; Janjaroen, Dao; Kuhlenschmidt, Mark S; Kuhlenschmidt, Theresa B; Nguyen, Thanh H

    2009-02-03

    A radial stagnation point flow (RSPF) system combined with a microscope was used to determine the deposition kinetics of Cryptosporidium parvum oocysts on quartz surfaces and silica surfaces coated with Suwannee River natural organic matter (SRNOM) in solutions with different ionic strengths. Microscopic evidence of C. parvum oocysts entrapped in the secondary minimum energy well was presented to show that among the entrapped C. parvum oocysts some were washed away by the radial flow and some were able to transfer to deep primary minima and become irreversibly deposited. Experimental data were compared with simulation results obtained by the convective-diffusion equation and Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The experimental results suggested that surface charge heterogeneity led to a higher attachment efficiency at low ionic strength. In addition, the maximum attachment efficiency was less than 1 at high ionic strength due to steric interaction.

  14. Impact of higher alginate expression on deposition of Pseudomonas aeruginosa in radial stagnation point flow and reverse osmosis systems.

    PubMed

    Herzberg, Moshe; Rezene, Tesfalem Zere; Ziemba, Christopher; Gillor, Osnat; Mathee, Kalai

    2009-10-01

    Extracellular polymeric substances (EPS) have major impact on biofouling of reverse osmosis (RO) membranes. On one hand, EPS can reduce membrane permeability and on the other, EPS production by the primary colonizers may influence their deposition and attachment rate and subsequently affect the biofouling propensity of the membrane. The role of bacterial exopolysaccharides in bacterial deposition followed by the biofouling potential of an RO membrane was evaluated using an alginate overproducing (mucoid) Pseudomonas aeruginosa. The mucoid P. aeruginosa PAOmucA22 was compared with its isogenic nonmucoid prototypic parent PAO1 microscopically in a radial stagnation point flow (RSPF) system for their bacterial deposition characteristics. Then, biofouling potential of PAO1 and PAOmucA22 was determined in a crossflow rectangular plate-and-frame membrane cell, in which the strains were cultivated on a thin-film composite, polyamide, flat RO membrane coupon (LFC-1) under laminar flow conditions. In the RSPF system, the observed deposition rate of the mucoid strain was between 5- and 10-fold lower than of the wild type using either synthetic wastewater medium (with ionic strength of 14.7 mM and pH 7.4) or 15 mM KCl solution (pH of 6.2). The slower deposition rate of the mucoid strain is explained by 5- to 25-fold increased hydrophilicity of the mucoid strain as compared to the isogenic wild type, PAO1. Corroborating with these results, a significant delay in the onset of biofouling of the RO membrane was observed when the mucoid strain was used as the membrane colonizer, in which the observed time for the induced permeate flux decline was delayed (ca. 2-fold). In conclusion, the lower initial cell attachment of the mucoid strain decelerated biofouling of the RO membrane. Bacterial deposition and attachment is a critical step in biofilm formation and governed by intimate interactions between outer membrane proteins of the bacteria and the surface. Shielding these

  15. Application of turbulent flow chromatography to the metabonomic analysis of human plasma: comparison with protein precipitation.

    PubMed

    Michopoulos, Filippos; Edge, Antony M; Theodoridis, Georgios; Wilson, Ian D

    2010-06-01

    The use of turbulent flow chromatography (TFC) as a method for the rapid metabonomic LC-MS analysis of plasma as an alternative to solvent-based protein precipitation has been investigated. This comparison has shown that TFC can be effectively used in this application with the benefit that off-line sample handling is significantly reduced. However, analysis of the data obtained via TFC for human plasma reveals substantial differences in the overall metabolite profiles compared with methanol-precipitated HPLC-MS. This seems in part at least to be related to greatly reduced amounts of phospholipids (ca. 10 fold reduction) for the turbulent flow methodology compared with protein-precipitated samples. The significance of these differences with respect to metabolite profiles as a result of the sample preparation method used are discussed.

  16. Effect of reference conditions on flow rate, modifier fraction and retention in supercritical fluid chromatography.

    PubMed

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

    2016-08-12

    When using compressible mobile phases such as fluidic CO2, the density, the volumetric flow rates and volumetric fractions are pressure dependent. The pressure and temperature definition of these volumetric parameters (referred to as the reference conditions) may alter between systems, manufacturers and operating conditions. A supercritical fluid chromatography system was modified to operate in two modes with different definition of the eluent delivery parameters, referred to as fixed and variable mode. For the variable mode, the volumetric parameters are defined with reference to the pump operating pressure and actual pump head temperature. These conditions may vary when, e.g. changing the column length, permeability, flow rate, etc. and are thus variable reference conditions. For the fixed mode, the reference conditions were set at 150bar and 30°C, resulting in a mass flow rate and mass fraction of modifier definition which is independent of the operation conditions. For the variable mode, the mass flow rate of carbon dioxide increases with system pump operating pressure, decreasing the fraction of modifier. Comparing the void times and retention factor shows that the deviation between the two modes is almost independent of modifier percentage, but depends on the operating pressure. Recalculating the set volumetric fraction of modifier to the mass fraction results in the same retention behaviour for both modes. This shows that retention in SFC can be best modelled using the mass fraction of modifier. The fixed mode also simplifies method scaling as it only requires matching average column pressure.

  17. Azimuthal ExB drift of electrons induced by the radial electric field flowing through a longitudinal magnetic channel with non-magnetized ions

    NASA Astrophysics Data System (ADS)

    Akatsuka, Hiroshi; Takeda, Jun; Nezu, Atsushi

    2016-09-01

    To examine of the effect of the radial electric field on the azimuthal electron motion under E × B field for plasmas with magnetized electrons and non-magnetized ions, an experimental study is conducted by a stationary plasma flow. The argon plasma flow is generated by a DC arc generator under atmospheric pressure, followed by a cw expansion into a rarefied gas-wind tunnel with a uniform magnetic field 0 . 16 T. Inside one of the magnets, we set a ring electrode to apply the radial electric field. We applied an up-down probe for the analysis of the electron motion, where one of the tips is also used as a Langmuir probe to measure electron temperature, density and the space potential. We found that the order of the radial electric field is about several hundred V/m, which should be caused by the difference in the magnetization between electrons and ions. Electron saturation current indicates the existence of the E × B rotation of electrons, whose order is about 2000 - 4000 m/s. The order of the observed electron drift velocity is consistent with the theoretical value calculated from the applied magnetic field and the measured electric field deduced from the space potential.

  18. Improved hydrophilic interaction chromatography LC/MS of heparinoids using a chip with postcolumn makeup flow.

    PubMed

    Staples, Gregory O; Naimy, Hicham; Yin, Hongfeng; Kileen, Kevin; Kraiczek, Karsten; Costello, Catherine E; Zaia, Joseph

    2010-01-15

    Heparan sulfate (HS) and heparin are linear, heterogeneous carbohydrates of the glycosaminoglycan (GAG) family that are modified by N-acetylation, N-sulfation, O-sulfation, and uronic acid epimerization. HS interacts with growth factors in the extracellular matrix, thereby modulating signaling pathways that govern cell growth, development, differentiation, proliferation, and adhesion. High-performance liquid chromatography (HPLC)-chip-based hydrophilic interaction liquid chromatography/mass spectrometry has emerged as a method for analyzing the domain structure of GAGs. However, analysis of highly sulfated GAG structures decasaccharide or larger in size has been limited by spray instability in the negative-ion mode. This report demonstrates that addition of postcolumn makeup flow to the amide-HPLC-chip configuration permits robust and reproducible analysis of extended GAG domains (up to degree of polymerization 18) from HS and heparin. This platform provides quantitative information regarding the oligosaccharide profile, degree of sulfation, and nonreducing chain termini. It is expected that this technology will enable quantitative, comparative glycomics profiling of extended GAG oligosaccharide domains of functional interest.

  19. 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.

  20. Hydrodynamic chromatography and field flow fractionation in finite aspect ratio channels.

    PubMed

    Shendruk, T N; Slater, G W

    2014-04-25

    Hydrodynamic chromatography (HC) and field-flow fractionation (FFF) separation methods are often performed in 3D rectangular channels, though ideal retention theory assumes 2D systems. Devices are commonly designed with large aspect ratios; however, it can be unavoidable or desirable to design rectangular channels with small or even near-unity aspect ratios. To assess the significance of finite-aspect ratio effects and interpret experimental retention results, an ideal, analytical retention theory is needed. We derive a series solution for the ideal retention ratio of HC and FFF rectangular channels. Rather than limiting devices' ability to resolve samples, our theory predicts that retention curves for normal-mode FFF are well approximated by the infinite plate solution and that the performance of HC is actually improved. These findings suggest that FFF devices need not be designed with large aspect ratios and that rectangular HC channels are optimal when the aspect ratio is unity.

  1. Radial engine

    SciTech Connect

    Kmicikiewicz, M.A.

    1988-03-01

    A radial engine is described comprising: a housing; equally spaced openings disposed in ring-like arrangement on the periphery of the housing; a piston and cylinder arrangement in each of the opening, a piston rod for each arrangement fixed to and extending radially inwardly from its respective piston and through its respective opening; shoe means pivotally attached at the other end of each of the piston rod; radial guide means extending in the housing in line with each of the piston rods, and the shoe means provided with guide means followers to ensure radial reciprocal movement of the piston rods and shoe means; and a connecting ring journaled on a crankshaft for circular translation motion in the housing, the ring including a circular rim. Each shoe means includes an arcuate follower member being slidably connected to the rim of the connecting ring.

  2. Flow rate dependent extra-column variance from injection in capillary liquid chromatography.

    PubMed

    Aggarwal, Pankaj; Liu, Kun; Sharma, Sonika; Lawson, John S; Dennis Tolley, H; Lee, Milton L

    2015-02-06

    Efficiency and resolution in capillary liquid chromatography (LC) can be significantly affected by extra-column band broadening, especially for isocratic separations. This is particularly a concern in evaluating column bed structure using non-retained test compounds. The band broadening due to an injector supplied with a commercially available capillary LC system was characterized from experimental measurements. The extra-column variance from the injection valve was found to have an extra-column contribution independent of the injection volume, showing an exponential dependence on flow rate. The overall extra-column variance from the injection valve was found to vary from 34 to 23 nL. A new mathematical model was derived that explains this exponential contribution of extra-column variance on chromatographic performance. The chromatographic efficiency was compromised by ∼130% for a non-retained analyte because of injection valve dead volume. The measured chromatographic efficiency was greatly improved when a new nano-flow pumping system with integrated injection valve was used.

  3. Rapid Catalyst Screening by a Continuous-Flow Microreactor Interfaced with Ultra High Pressure Liquid Chromatography

    PubMed Central

    Fang, Hui; Xiao, Qing; Wu, Fanghui; Floreancig, Paul E.; Weber, Stephen G.

    2010-01-01

    A high-throughput screening system for homogeneous catalyst discovery has been developed by integrating a continuous-flow capillary-based microreactor with ultra-high pressure liquid chromatography (UHPLC) for fast online analysis. Reactions are conducted in distinct and stable zones in a flow stream that allows for time and temperature regulation. UHPLC detection at high temperature allows high throughput online determination of substrate, product, and byproduct concentrations. We evaluated the efficacies of a series of soluble acid catalysts for an intramolecular Friedel-Crafts addition into an acyliminium ion intermediate within one day and with minimal material investment. The effects of catalyst loading, reaction time, and reaction temperature were also screened. This system exhibited high reproducibility for high-throughput catalyst screening and allowed several acid catalysts for the reaction to be identified. Major side products from the reactions were determined through off-line mass spectrometric detection. Er(OTf)3, the catalyst that showed optimal efficiency in the screening, was shown to be effective at promoting the cyclization reaction on a preparative scale. PMID:20666502

  4. 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.

  5. Large-scale purification of pharmaceutical-grade plasmid DNA using tangential flow filtration and multi-step chromatography.

    PubMed

    Sun, Bo; Yu, XiangHui; Yin, Yuhe; Liu, Xintao; Wu, Yongge; Chen, Yan; Zhang, Xizhen; Jiang, Chunlai; Kong, Wei

    2013-09-01

    The demand for pharmaceutical-grade plasmid DNA in vaccine applications and gene therapy has been increasing in recent years. In the present study, a process consisting of alkaline lysis, tangential flow filtration, purification by anion exchange chromatography, hydrophobic interaction chromatography and size exclusion chromatography was developed. The final product met the requirements for pharmaceutical-grade plasmid DNA. The chromosomal DNA content was <1 μg/mg plasmid DNA, and RNA was not detectable by agarose gel electrophoresis. Moreover, the protein content was <2 μg/mg plasmid DNA, and the endotoxin content was <10 EU/mg plasmid DNA. The process was scaled up to yield 800 mg of pharmaceutical-grade plasmid DNA from approximately 2 kg of bacterial cell paste. The overall yield of the final plasmid DNA reached 48%. Therefore, we have established a rapid and efficient production process for pharmaceutical-grade plasmid DNA.

  6. Fully automated screening of veterinary drugs in milk by turbulent flow chromatography and tandem mass spectrometry

    PubMed Central

    Stolker, Alida A. M.; Peters, Ruud J. B.; Zuiderent, Richard; DiBussolo, Joseph M.

    2010-01-01

    There is an increasing interest in screening methods for quick and sensitive analysis of various classes of veterinary drugs with limited sample pre-treatment. Turbulent flow chromatography in combination with tandem mass spectrometry has been applied for the first time as an efficient screening method in routine analysis of milk samples. Eight veterinary drugs, belonging to seven different classes were selected for this study. After developing and optimising the method, parameters such as linearity, repeatability, matrix effects and carry-over were studied. The screening method was then tested in the routine analysis of 12 raw milk samples. Even without internal standards, the linearity of the method was found to be good in the concentration range of 50 to 500 µg/L. Regarding repeatability, RSDs below 12% were obtained for all analytes, with only a few exceptions. The limits of detection were between 0.1 and 5.2 µg/L, far below the maximum residue levels for milk set by the EU regulations. While matrix effects—ion suppression or enhancement—are obtained for all the analytes the method has proved to be useful for screening purposes because of its sensitivity, linearity and repeatability. Furthermore, when performing the routine analysis of the raw milk samples, no false positive or negative results were obtained. PMID:20379812

  7. Evaluation of dual flow counter-current chromatography and intermittent counter-current extraction.

    PubMed

    Ignatova, Svetlana; Hewitson, Peter; Mathews, Ben; Sutherland, Ian

    2011-09-09

    The aim of this research is to compare two continuous extraction technologies, intermittent counter-current extraction (ICcE) and dual flow counter-current chromatography (DFCCC), in terms of loading and throughput using the GUESSmix, and show the advantages and disadvantages of the two methods. A model sample containing caffeine, vanillin, naringenin and carvone, with a total load of 11.2 g, was employed with a hexane-ethyl acetate-methanol-water (2:3:2:3) phase system to evaluate an ICcE method on a preparative (912 ml coil volume) DE-Midi instrument. While DFCCC was carried out on a specially designed preparative (561 ml coil volume) bobbin installed in a similar Midi instrument case. While similar throughputs of 7.8 g/h and 6.9 g/h were achieved for the ICcE and DFCCC methods respectively, ICcE was demonstrated to have a number of advantages over DFCCC.

  8. 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.

  9. 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.

  10. 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.

  11. Axisymmetric rotational stagnation point flow impinging radially a permeable stretching/shrinking surface in a nanofluid using Tiwari and Das model.

    PubMed

    Roşca, Natalia C; Pop, Ioan

    2017-01-12

    In this paper, the problem of normal impingement rotational stagnation-point flow on a radially permeable stretching sheet in a viscous fluid, recently studied in a very interesting paper, is extended to a water-based nanofluid. A similarity transformation is used to reduce the system of governing nonlinear partial differential equations to a system of ordinary differential equations, which is then solved numerically using the function bvp4c from Matlab. It is found that dual (upper and lower branch) solutions exist for some values of the governing parameters. From the stability analysis, it is found that the upper branch solution is stable, while the lower branch solution is unstable. Sample velocity and temperature profiles along both solution branches are graphically presented.

  12. Axisymmetric rotational stagnation point flow impinging radially a permeable stretching/shrinking surface in a nanofluid using Tiwari and Das model

    NASA Astrophysics Data System (ADS)

    Roşca, Natalia C.; Pop, Ioan

    2017-01-01

    In this paper, the problem of normal impingement rotational stagnation-point flow on a radially permeable stretching sheet in a viscous fluid, recently studied in a very interesting paper, is extended to a water-based nanofluid. A similarity transformation is used to reduce the system of governing nonlinear partial differential equations to a system of ordinary differential equations, which is then solved numerically using the function bvp4c from Matlab. It is found that dual (upper and lower branch) solutions exist for some values of the governing parameters. From the stability analysis, it is found that the upper branch solution is stable, while the lower branch solution is unstable. Sample velocity and temperature profiles along both solution branches are graphically presented.

  13. Axisymmetric rotational stagnation point flow impinging radially a permeable stretching/shrinking surface in a nanofluid using Tiwari and Das model

    PubMed Central

    Roşca, Natalia C.; Pop, Ioan

    2017-01-01

    In this paper, the problem of normal impingement rotational stagnation-point flow on a radially permeable stretching sheet in a viscous fluid, recently studied in a very interesting paper, is extended to a water-based nanofluid. A similarity transformation is used to reduce the system of governing nonlinear partial differential equations to a system of ordinary differential equations, which is then solved numerically using the function bvp4c from Matlab. It is found that dual (upper and lower branch) solutions exist for some values of the governing parameters. From the stability analysis, it is found that the upper branch solution is stable, while the lower branch solution is unstable. Sample velocity and temperature profiles along both solution branches are graphically presented. PMID:28079124

  14. 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...

  15. 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 × 1000 mm) was employed to generate desired pressure (approximately 13.0 MPa) when warm acidic water (70 °C) was delivered as extraction solvent at a high flow rate (2.5 mL/min), and a hollow guard column (3.0 × 4.0 mm) 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 (0-3.0 min) and elution (3.0-35.0 min) 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.

  16. 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.

  17. Effects of climatic conditions on radial growth and sap-flow along an elevation gradient in an inner-alpine dry valley

    NASA Astrophysics Data System (ADS)

    Obojes, Nikolaus; Newesely, Christian; Bertoldi, Giacomo; Tassser, Erich; Oberhuber, Walter; Mayr, Stefan; Tappeiner, Ulrike

    2016-04-01

    Water availability in mountain forests might change in the future due to rising temperatures and changing precipitation patterns, affecting tree water relations and growth conditions. Changing temperature and precipitation along an elevation gradient in an inner-alpine dry valley in South Tyrol-Italy were used to investigate possible effects of climate change on the transpiration and growth of European Larch (Larix decidua). Stem circumference variation of European Larch was measured for 4 years (2012-2015) with automatic band dendrometers and sap flow for 2 years (2013-2014) with trunk heat balance sensors at 3 sites at elevations of 1115 m, 1715 m, and 1990 m above sea level at a SE-exposed slope. During the first two, rather dry, years, transpiration and stem circumference were reduced during dry periods of one to three weeks at the two lower but not at the highest site. As a consequence, overall yearly radial growth was largest at the highest site in those two years. In 2014, with very high precipitation and colder summer temperatures no correlation of elevation, transpiration, and radial growth was observed. In 2015, with a dry and hot summer, initially high growth rates were strongly reduced after the end of May at the two lower sites. Overall the radial growth of Larix decidua seems to be limited by water scarcity up to an elevation of more than 1700 m a.s.l. in our study area except for unusually wet years. Our 4-year measurements were confirmed by dendro-climatic analysis of stem cores taken at five sites (the three original ones plus two additional sites at 1070 and at the forest line at 2250m) covering the last 50 to 150 years. Year ring widths were lower and highly correlated to precipitation at the lowest sites, and overall highest at the 1990 m site. Our results show that the growth of Larix decidua, which is often considered as more drought resistant than e.g. Picea abies, is limited by water availability at dry conditions in the Alps which might

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

    PubMed Central

    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

  19. 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

  20. 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 μL 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 μL 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

  1. 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

  2. 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.

  3. Numerical investigation into the effects of ordered particle packing and slip flow on the performance of chromatography.

    PubMed

    Yan, Xiaohong; Wang, Qiuwang

    2013-05-01

    The pressure drop and the plate height of chromatography columns packed with particles in the face-centered cubic, the body-centered cubic and the simple cubic configurations are calculated by a volume averaging method model. It is found that the Kozeny-Carman equation provides a reasonable prediction of the pressure drop when particles are in the face-centered cubic configuration, but overestimates the pressure drop when particles are in the body-centered cubic and the simple cubic configurations. The face-centered cubic configuration has the advantage to provide a smaller longitudinal dispersion coefficient than the body-centered cubic, the simple cubic, and the random configurations. The pressure drop and the plate height for slip flow through particles in the face-centered cubic configuration are lower than that for no-slip flow. The values of the smallest reduced plate height of columns packed with particles in the face-centered cubic configuration for no-slip flow and slip flow are about 0.084 and 0.059, respectively. The plate height of the ordered particle packing structures is smaller and the effect of slip flow on the plate height is less remarkable than results reported in literature.

  4. 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.

  5. Deposition kinetics of bacteriophage MS2 on a silica surface coated with natural organic matter in a radial stagnation point flow cell.

    PubMed

    Yuan, Baoling; Pham, Mai; Nguyen, Thanh H

    2008-10-15

    A quartz crystal microbalance (QCM) coupled with a radial stagnation point flow (RSPF) cell was used to study deposition kinetics of bacteriophage MS2 on silica surface coated with Suwannee River natural organic matter (SRNOM). Three stocks of MS2 stored in 1 mM NaHCO3, deionized (DI) water or phosphate buffer saline (PBS) solution were studied. MS2 stored in PBS solution were found to aggregate at all studied ionic strengths from 3 mM to 200 mM, while MS2 stored in DI water and bicarbonate solutions remained monodispersed. Isoelectric points of MS2 storedin PBS solution were lower than for those stored in DI water and 1 mM NaHCO3 solution. Nonrepulsive deposition rates of MS2 on silica surface coated with poly-L-lysine (PLL) were independent of ionic strength. In contrast MS2 deposition rates on bare silica surface or silica surface coated with SRNOM increased gradually and stabilized at an ionic strength of 60 mM. MS2 deposition rates on bare silica surface were higher than those on silica surface coated with SRNOM at low ionic strengths. Deposition rates on these two surfaces were similar at high ionic strengths. Experimental data suggest that electrostatic and steric interactions were the two main deposition mechanisms of MS2 on either bare silica or silica surface coated with SRNOM.

  6. Application of a radial-flow bioreactor in the production of beta1,3-N-acetylglucosaminyltransferase-2 fused with GFPuv using stably transformed insect cell lines.

    PubMed

    Kwon, Mi Sun; Kato, Tatsuya; Dojima, Takashi; Park, Enoch Y

    2005-08-01

    An RFB (radial-flow bioreactor) with a reactor volume of 5 ml was applied to produce human beta3GnT (beta1,3-N-acetylglucosaminyltransferase) using two stably transformed insect cell lines. When air was supplied to the RFB, cell growth stopped at 4 days of culture and beta3GnT was not detected. However, with a supply of pure oxygen, the cell concentration, assumed from glucose consumption, increased by 1.3x10(7) cells/ml. Insect cells attached to poly(vinyl alcohol) matrixes packed in the RFB and grew confluently; 5.6 m-units/ml beta3GnT was produced under the conditions of pure oxygen supply and addition of glucose and glutamine. This RFB was first applied in beta3GnT production using stably transformed insect cells. The amount of beta3GnT production in only a 5 ml-scale RFB was comparable with that of a 100 ml shaking flask culture.

  7. A Simple and Sensitive Method for Quantitative Measurement of Methylmalonic Acid by Turbulent Flow Chromatography and Tandem Mass Spectrometry

    PubMed Central

    Tecleab, AG; Schofield, RC; Ramanathan, LV; Carlow, Dean C

    2016-01-01

    A simple and sensitive method for the detection of methylmalonic acid in serum without derivatization has been developed. This method implements protein precipitation using methanol followed by additional sample clean up by turbulent flow liquid chromatography (TFLC). The sample was directly injected into the turbulent flow liquid chromatography tandem mass spectrometry system (TFLC-MS/MS) for online extraction followed by HPLC separation. The eluent was transferred to the mass spectrometer and ionized by heated electrospray negative ionization (HESI) and the analyte was quantified using a six-point calibration curve. The validated analytical measurement range (AMR) is 30–1,000 nMol/L. Dilutions of 10 and 200-fold were validated giving a clinical reportable range (CRR) of 30–200,000 nMol/L. The between-day and within-day imprecision values at concentrations spanning the AMR were less than 15%. This method was compared to an established LC-MS/MS method at a CLIA certified national reference laboratory and shows an excellent correlation with our TFLC-MS/MS method. PMID:27833786

  8. Flow modulation comprehensive two-dimensional gas chromatography-mass spectrometry using ≈4 mL min(-1) gas flows.

    PubMed

    Franchina, Flavio A; Maimone, Mariarosa; Tranchida, Peter Q; Mondello, Luigi

    2016-04-08

    The main objective of the herein described research was focused on performing satisfactory flow modulation (FM), in comprehensive two-dimensional gas chromatography-mass spectrometry (GC×GC-MS), using an MS-compatible second-dimension gas flow of approx. 4 mL min(-1). The FM model used was based on that initially proposed by Seeley et al. [3]. The use of limited gas flows was enabled through fine tuning of the FM parameters, in particular the duration of the re-injection (or flushing) process. Specifically, the application of a long re-injection period (i.e., 700 ms) enabled efficient accumulation-loop flushing with gas flows of about 4 mL min(-1). It was possible to apply such extended re-injection periods by using different restrictor lengths in the connections linking the modulator to the auxiliary pressure source. FM GC×GC-MS applications were performed on a mixture containing C9-10 alkanes, and on a sample of essential oil. GC×GC-MS sensitivity was compared with that attained by using conventional GC-MS analysis, in essential oil applications. It was observed that signal intensities were, in general, considerably higher in the FM GC×GC-MS experiments.

  9. 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

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

    PubMed

    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.

  11. Parallel segmented outlet flow high performance liquid chromatography with multiplexed detection.

    PubMed

    Camenzuli, Michelle; Terry, Jessica M; Shalliker, R Andrew; Conlan, Xavier A; Barnett, Neil W; Francis, Paul S

    2013-11-25

    We describe a new approach to multiplex detection for HPLC, exploiting parallel segmented outlet flow - a new column technology that provides pressure-regulated control of eluate flow through multiple outlet channels, which minimises the additional dead volume associated with conventional post-column flow splitting. Using three detectors: one UV-absorbance and two chemiluminescence systems (tris(2,2'-bipyridine)ruthenium(III) and permanganate), we examine the relative responses for six opium poppy (Papaver somniferum) alkaloids under conventional and multiplexed conditions, where approximately 30% of the eluate was distributed to each detector and the remaining solution directed to a collection vessel. The parallel segmented outlet flow mode of operation offers advantages in terms of solvent consumption, waste generation, total analysis time and solute band volume when applying multiple detectors to HPLC, but the manner in which each detection system is influenced by changes in solute concentration and solution flow rates must be carefully considered.

  12. Flow-injection sample preconcentration for ion-pair chromatography of trace metals in waters.

    PubMed

    Pobozy, Ewa; Halko, Radoslav; Krasowski, Marcin; Wierzbicki, Tomasz; Trojanowicz, Marek

    2003-05-01

    Selected trace transition metal ions have been determined in an FIA/HPLC hyphenated system using on-line preconcentration on cellulose functionalised sorbent Cellex P. For HPLC separation ion-pair chromatography was employed with spectrophotometric detection at 510 nm using post-column derivatisation with PAR. Favourable kinetic conditions of sorption and elution as well as optimisation of hyphenated system allowed to obtain detection limits at sub-microgL(-1) level at 25 min preconcentration time. The developed method was employed for determination of Co(II), Ni(II), Cd(II) and Mn(II) in river water with reasonable agreement of obtained results with electrothermal AAS determination.

  13. Whether radial receptive field organization of the fourth extrastriate crescent (area V4A) gives special advantage for analysis of the optic flow. Comparison with the first crescent (area V2).

    PubMed

    Levichkina, E V; Loshkarev, A A; Rodionova, E I; Popova, E P; Pigarev, I N

    2007-09-01

    Recently, elongated comet-shaped receptive fields were discovered in the fourth extrastriate crescent (area V4A) of cats and monkeys. It was shown that the long axes of these receptive fields were oriented radially toward the centre of the retina. Such unusual "radial" organization of this extrastriate area led to the assumption that these neurons may contribute to the analysis of optic flow. To investigate this assumption we recorded activity of neurons in the V4A of cats during real motion in depth toward or away from a stationary visual scene. Responses of neurons in area V4A were compared with activity of neurons in area V2 under similar conditions of stimulation. Area V2 is known to be sensitive to motion but does not have radial organization. It was found that a substantial number of visual neurons in both areas did not fire at all when cats were exposed to motion in depth. Nevertheless, neurons with selective activation to direction of motion in depth were identified, but comparable numbers were found in both areas studied. We conclude that radial organization of the fourth extrastriate crescent does not provide any special advantage for the analysis of optic flow information.

  14. Radial cold trap

    DOEpatents

    Grundy, Brian R.

    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. Analysis of organophosphorus flame retardants in environmental and biotic matrices using on-line turbulent flow chromatography-liquid chromatography-tandem mass spectrometry.

    PubMed

    Giulivo, Monica; Capri, Ettore; Eljarrat, Ethel; Barceló, Damià

    2016-11-25

    A fast on-line analytical method based on turbulent flow chromatography (TFC) in combination with tandem mass spectrometry (MS-MS) has been applied for the analysis of fourteen organophosphorus flame retardants (OPFRs) in sediment and fish samples. Applying this technique, time-consuming sample preparation steps were eliminated. The extraction was performed by ultrasound liquid extraction for biota and by pressurized liquid extraction for sediments. After extraction, environmental and biotic extracts were directly injected to the chromatographic system and analytes were concentrated into the cleanup loading column. Thereafter, analytes were transferred into the analytical column for subsequent detection by MS-MS. Analytical parameters showed acceptable recoveries (between 47 and 112% for sediment, and between 47 and 98% for fish) with very low relative standard deviations (always below 8.8% for sediment, and below 16% for fish). Moreover, mLODs and mLOQs are similar or even lower than those reported in other works using off-line methodologies. mLODs ranged between 0.02 and 1.25ng/g dry weight (dw) and between 0.19 and 19.3ng/g lipid weight (lw) for sediments and fish samples, respectively. The applicability of the developed methodology was demonstrated by the analysis of real samples, corresponding to river sediments as well as river and marine fish samples. OPFRs were detected in all samples, with values up to 549ng/g dw, 15.8ng/g lw and 646ng/g lw for sediment, marine fish and river fish, respectively.

  17. 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.

  18. Improved liquid chromatography-MS/MS of heparan sulfate oligosaccharides via chip-based pulsed makeup flow.

    PubMed

    Huang, Yu; Shi, Xiaofeng; Yu, Xiang; Leymarie, Nancy; Staples, Gregory O; Yin, Hongfeng; Killeen, Kevin; Zaia, Joseph

    2011-11-01

    Microfluidic chip-based hydrophilic interaction chromatography (HILIC) is a useful separation system for liquid chromatography-mass spectrometry (LC-MS) in compositional profiling of heparan sulfate (HS) oligosaccharides; however, ions observed using HILIC LC-MS are low in charge. Tandem MS of HS oligosaccharide ions with low charge results in undesirable losses of SO(3) from precursor ions during collision induced dissociation. One solution is to add metal cations to stabilize sulfate groups. Another is to add a nonvolatile, polar compound such as sulfolane, a molecule known to supercharge proteins, to produce a similar effect for oligosaccharides. We demonstrate use of a novel pulsed makeup flow (MUF) HPLC-chip. The chip enables controlled application of additives during specified chromatographic time windows and thus minimizes the extent to which nonvolatile additives build up in the ion source. The pulsed MUF system was applied to LC-MS/MS of HS oligosaccharides. Metal cations and sulfolane were tested as additives. The most promising results were obtained for sulfolane, for which supercharging of the oligosaccharide ions increased their signal strengths relative to controls. Tandem MS of these supercharged precursor ions showed decreased abundances of product ions from sulfate losses yet more abundant product ions from backbone cleavages.

  19. Continuous flow microextraction combined with high-performance liquid chromatography for the analysis of pesticides in natural waters.

    PubMed

    He, Yi; Lee, Hian Kee

    2006-07-28

    Continuous flow microextraction (CFME) combined with high-performance liquid chromatography-ultraviolet (HPLC-UV) detection has been applied to the analysis of five widely used pesticides, simazine, fensulfothion, etridiazole, mepronil and bensulide, present at trace levels in water samples. CFME employs a single organic solvent drop positioned at the tip of a polyether ether ketone (PEEK) tubing, which is immersed in a continuous flowing aqueous sample solution in a 0.5-ml glass chamber. The PEEK tubing acts as the organic drop holder and fluid delivery duct. Analytes are partitioned between the organic drop and the bulk sample solution. Important extraction factors including type of solvent, its volume, sample solution flow rate, extraction time, its pH and addition of salt were investigated. All pesticides exhibit good linearity in the investigated concentration range of 25-250 ng ml(-1) with coefficients of determination (R2) ranging from 0.9879 to 0.9999 under the optimized conditions. Detection limits lower than 4 ng ml(-1) were obtained for all analytes. The method was evaluated by analyzing natural water sample collected from a reservoir in Singapore. This study for the first time demonstrated the compatibility of CFME procedure and HPLC separation.

  20. 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.

  1. 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.

  2. 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.

  3. Losses in radial inflow turbines

    NASA Technical Reports Server (NTRS)

    Khalil, I. M.; Tabakoff, W.; Hamed, A.

    1976-01-01

    A study was conducted to determine experimentally and theoretically the losses in radial inflow turbine nozzles. Extensive experimental data was obtained to investigate the flow behavior in a full-scale radial turbine stator annulus. A theoretical model to predict the losses in both the vaned and vaneless regions of the nozzle was developed. In this analysis, the interaction effects between the stator and the rotor are not considered. It was found that the losses incurred due to the end wall boundary layers can be significant, especially if they are characterized by a strong crossflow. The losses estimated using the analytical study are compared with the experimentally determined values.

  4. A free-flowing soap film combined with cavity ring-down spectroscopy as a detection system for liquid chromatography.

    PubMed

    Vogelsang, Markus; Welsch, Thomas; Jones, Harold

    2010-05-07

    We have shown that a free-flowing soap film has sufficiently high-quality optical properties to allow it to be used in the cavity of a ring-down spectrometer (CRDS). The flow rates required to maintain a stable soap film were similar to those used in liquid chromatography and thus allowed interfacing with an HPLC system for use as an optical detector. We have investigated the properties of the system in a relevant analytical application. The soap film/CRDS combination was used at 355 nm as a detector for the separation of a mixture of nitroarenes. These compounds play a role in the residue analysis of areas contaminated with explosives and their decomposition products. In spite of the short absorption path length (9 microm) obtained by the soap film, the high-sensitivity of CRDS allowed a limit of detection of 4 x 10(-6) in absorption units (AU) or less than 17 fmol in the detection volume to be achieved.

  5. Flow mechanism of Forchheimer's cubic equation in high-velocity radial gas flow through porous media. [High-velocity, high-pressure gas flow through porous media near the wellbore

    SciTech Connect

    Ezeudembah; Dranchuk, P.M.

    1982-09-01

    Until recently, the visco-inertial flow equation, which is an adaptation of Forchheimer's quadratic equation, has been used to describe gas flow behavior at higher flow rates and pressures. The inability of this equation, in some cases, to fully describe high-velocity, high-pressure gas flow behavior, especially around the well bore, led to the consideration of other empirical equations. In this paper, formal derivation of Forchheimer's cubic equation is made by considering the kinetic energy equation of mean flow and dimensional relations for one-dimensional, linear, incompressible fluid flow. By the addition of the cubic term, this equation is regarded as a modified Forchheimer's quadratic equation which accounts for the flow rates obtained beyond the laminar flow condition. The cubic equation spans a wide range of flow rates and regimes, i.e. Darcy type, inertial type, and turbulent. For suitable use in gas flow studies, this equation has been adapted, modified, and corrected for the gas slippage effect. The physical basis of the cubic term has been established by using boundary layer theory to explain the high-velocity, high-pressure flow behavior through a porous path. Gamma, the main parameter in the cubic term, is directly related to a characteristic, dimensionless shape factor which is significant at higher flow rates. It is inversely related to viscosity, but has no dependence on the gas slippage coefficient in the higher flow regime.

  6. Rapid Identification of Airborne Biological Particles by Flow Cytometry, Gas Chromatography, and Genetic Probes.

    DTIC Science & Technology

    1997-09-01

    isolated culture of Heterobasidion annosum. The yeast and bacterial specimens have not been identified, since their identifications require biochemical...RZ-SZAACH. DEVELOPMENr & E-NONEERINO CENTER U.S. AR..!f CHR ICAL AND SIOLOGIC-NL DEFENSE COMNMA1D RAPID IDENTIFICATION OF AIRBORNE BIOLOGICAL...Ground, Maryland 21010-5423 ERRATUM SHEET 30 October 1997 REPORT NO. ERDEC-TR-443 TITLE RAPID IDENTIFICATION OF AIRBORNE BIOLOGICAL PARTICLES BY FLOW

  7. Direct liquid sample introduction for flow injection analysis and liquid chromatography with inductively coupled argon plasma spectrometric detection

    SciTech Connect

    Lawrence, K.E.; Rice, G.W.; Fassel, V.A.

    1984-02-01

    The coupling of flow injection analysis (FIA) or high-performance liquid chromatography (HPLC) techniques to inductively coupled plasma atomic emission spectrometry (ICP-AES) offers new and attractive approaches for the determination of elemental concentrations in a wide variety of sample matrices. One of the most attractive features that FIA offers is a rapid and precise means of automating sample introduction into an ICP for simultaneous, multielement analysis at the trace, minor, and major constituent level with minimal sample consumption. The utilization of the ICP as a detector for HPLC retains most of the advantages of FIA-ICP, while providing the analyst with a powerful and versatile means of compound separation. This added dimension becomes particularly important when metal speciation is of primary interest, rather than total metal content. To date, the coupling of FIA and HPLC to the ICP has only been accomplished using conventional cross-flow, concentric, or Babington-type pneumatic nebulizers. Limits of detection under these conditions have generally been observed to be poorer when compared to conventional continuous sample flow conditions. These limitations have been attributed to the large dead-volume and the sample losses associated with conventional nebulizers and band broadening of eluents from FIA transfer tubing or HPLC columns prior to entering the nebulizer unit. In an effort to resolve these difficulties, a microconcentric nebulizer has been developed which is inserted directly into the tip of a conventional sample introduction tube of an ICP torch. Preliminary data on the potential utility of direct liquid sample introduction into the ICP are presented. 12 references, 6 figures, 1 table.

  8. Ultra-low Flow Liquid Chromatography Assay with Ultraviolet (UV) Detection for Piperine Quantitation in Human Plasma

    PubMed Central

    Kakarala, Madhuri; Dubey, Shiv Kumar; Tarnowski, Malloree; Cheng, Connie; Liyanage, Samadhi; Strawder, Terrence; Tazi, Karim; Sen, Ananda; Djuric, Zora; Brenner, Dean E.

    2015-01-01

    A robust and sensitive ultra-low flow liquid chromatography (UFLC) method that can reproducibly, at reasonable cost, detect low concentrations of piperine from human plasma is necessary. Piperine in plasma was separated and quantified by a gradient method using ultraviolet detection at a maximal absorbance wavelength of 340 nm. An aliquot was injected onto a reversed-phase column Waters SymmetryShield, 2.1 × 100 mm, 3.5 μm, C18 column, attached to a Waters absorbosphere, 4.6 × 30 mm, C18 guard column and eluted with a mobile phase containing a mixture of acetonitrile/water/ acetic acid (25:74.9:0.1, v/v/v) on line A and acetonitrile/acetic acid (99.9:0.1, v/v) on line B. The flow rate was 0.3 mL/min. The gradient method consisted of an opening condition of 20% pump B, with a linear increase to 37% pump B over 8 min, then a linear increase to 100% pump B at 11 min, 2 min at 100% pump B, and then a return to the opening condition (20% pump B) via a linear gradient over 2 min, followed by 5 min re-equilibration at opening conditions. The total run time was 20 min for each sample. All samples were processed protected from ambient light to avoid isomerization of piperine. The plasma assay was linear with R = 0.9995, with a lower limit of detection [signal-to-noise (S/N) > 5:1] of 100 pg of piperine loaded into the analytical system with acceptable accuracy and precision. Extraction recoveries of piperine from human plasma were 88% for quality control high (QCH), 93% for quality control medium (QCM), and 90% for quality control low (QCL), and the matrix effect was <12%. Piperine was quantifiable from a 50 mg oral dose given to human volunteers. A UFLC method for the rapid assay of human plasma with sensitivity to detect as low as 5 ng/mL piperine was developed. The method sensitivity equals that of liquid chromatography/tandem mass spectrometry (LC/MSMS) methods with much less cost. PMID:20465211

  9. Radial Artery Catheterization

    MedlinePlus

    ... of the radial artery for cardiac catheterization procedures. Advantages of Radial Artery Catheterization Any catheter placement into ... walk, and eat immediately. This is a particular advantage for patients with back problems because there is ...

  10. Effects of various factors on Doppler flow ultrasonic radial and coccygeal artery systolic blood pressure measurements in privately-owned, conscious dogs

    PubMed Central

    Mooney, Allison P.; Mawby, Dianne I.; Price, Joshua M.

    2017-01-01

    Objective The purpose of this study was to assess the effects of age, body condition score (BCS) and muscle condition score (MCS) on indirect radial and coccygeal Doppler systolic arterial blood pressure (SAP) measurements in dogs. Methods Sixty-two privately-owned dogs were enrolled between June and July 2016. The BCS and MCS were determined by two investigators. Blood pressure was measured per published guidelines and using headphones, and the order of measurement site was randomized. Dogs were positioned in right lateral recumbency for radial measurements and sternal recumbency or standing for coccygeal measurements. Associations between SAP and other variables were assessed by correlation coefficients and analysis of covariance. Results Radial and coccygeal SAP measurements were moderately correlated (r = 0.45, P < 0.01). Radial SAP measurements were higher than coccygeal SAP measurements (mean difference 9 mmHg, P < 0.01), but discordance occurred in both directions. No difference was observed between the first measurement taken, the average of measurements 2–6, or the average of all 6 measurements for either the radial (128, 129, and 129 mmHg; P = 0.36) or coccygeal (121, 122, and 122 mmHg; P = 0.82) site. Associations were not found between SAP measurements for either site and age, weight, BCS, MCS, anxiety score, or cuff size. Heart rate decreased significantly from the start of acclimation to the end of the first data collection series regardless of site (P < 0.01). Conclusions and Clinical Relevance Initial measurement site can be based on patient and operator preference given lack of associations with patient variables, but the same site should be used for serial SAP measurements given discordant results between sites. PMID:28348930

  11. 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.

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

    PubMed

    Cegłowski, Michał; 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 1 W, 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 35 ng/cm(2) of a pyrazole derivative.

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

    PubMed

    Chambliss, Allison B; Füzéry, 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 μL 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 %.

  14. Comparison of segmented flow analysis and ion chromatography for the quantitative characterization of carbohydrates in tobacco products.

    PubMed

    Shifflett, John R; Jones, Lindsey A; Limowski, Edward R; Bezabeh, Dawit Z

    2012-11-28

    Segmented flow analysis (SFA) and ion chromatography with pulsed amperometric detection (IC-PAD) are widely used analytical techniques for the analysis of glucose, fructose, and sucrose in tobacco. In the work presented here, 27 cured tobacco leaves and 21 tobacco products were analyzed for sugars using SFA and IC. The results of these analyses demonstrated that both techniques identified the same trends in sugar content across tobacco leaf and tobacco product types. However, comparison of results between techniques was limited by the selectivity of the SFA method, which relies on the specificity of the reaction of p-hydroxybenzoic acid hydrazide (PAHBAH) with glucose and fructose to generate a detectable derivative. Sugar amines and chlorogenic acid, which are found in tobacco, are also known to react with PAHBAH to form a reaction product that interferes with the analysis of fructose and glucose. To mitigate this problem, solid phase extraction (SPE) was used to remove interferences such as sugar amines and chlorogenic acid from sample matrices prior to SFA. A combination of C18 and cation exchange solid phase extraction cartridges was used, and the results from SFA and IC analyses showed significant convergence in the results of both analytical methods. For example, the average difference between the results from the SFA and IC analyses for flue-cured tobacco samples dropped by 73% when the two-step C18/cation exchange resin sample cleanup was used.

  15. Size Dependent Lipidomic Analysis of Urinary Exosomes from Patients with Prostate Cancer by Flow Field-Flow Fractionation and Nanoflow Liquid Chromatography-Tandem Mass Spectrometry.

    PubMed

    Yang, Joon Seon; Lee, Jong Cheol; Byeon, Seul Kee; Rha, Koon Ho; Moon, Myeong Hee

    2017-02-21

    Exosomes are membrane-bound extracellular vesicles involved in intercellular communication and tumor cell metastasis. In this study, flow field-flow fractionation (FlFFF) was utilized to separate urinary exosomes by size, demonstrating a significant difference in exosome sizes between healthy controls and patients with prostate cancer (PCa). Exosome fractions of different sizes were collected for microscopic analysis during an FlFFF run and evaluated with exosome marker proteins using Western blot analysis. The results indicated that exosomes of different sizes originated from different types of cells. Collected exosome fractions were further examined using nanoflow ultrahigh performance liquid chromatography-electrospray ionization-tandem mass spectrometry (nUPLC-ESI-MS/MS) for lipidomic analysis. A total of 162 lipids (from 286 identified) were quantified using a selected reaction monitoring (SRM) method. The overall amount of lipids increased by 1.5- to 2-fold in patients with PCa and degree of increase was more significant in the smaller fractions (diameter <150 nm) than in the larger ones (diameter >150 nm) some classes of lipids. In addition, neutral lipids like diacylglycerol (DAG) and triacylglycerol (TAG) decreased in all exosomes without size dependency. Moreover, a dramatic increase in 22:6/22:6-phosphatidylglycerol (PG) was observed and significant decrease in (16:0,16:0)- and (16:1, 18:1)-DAG species (nearly 5-fold) and high abundant TAG species (>2.5-fold) was observed in patients with PCa. The results of this study indicate that FlFFF can be employed for the high-speed screening of urinary exosome sizes in patients with PCa and lipidomic analysis of the fractionated exosomes has potential for developing and distinguishing biomarkers of PCa.

  16. Integration of continuous-flow accelerator mass spectrometry with chromatography and mass-selective detection.

    PubMed

    Flarakos, Jimmy; Liberman, Rosa G; Tannenbaum, Steven R; Skipper, Paul L

    2008-07-01

    Physical combination of an accelerator mass spectrometry (AMS) instrument with a conventional gas chromatograph-mass spectrometer (GC/MS) is described. The resulting hybrid instrument (GC/MS/AMS) was used to monitor mass chromatograms and radiochromatograms simultaneously when (14)C-labeled compounds were injected into the gas chromatograph. Combination of the two instruments was achieved by splitting the column effluent and directing half to the mass spectrometer and half to a flow-through CuO reactor in line with the gas-accepting AMS ion source. The reactor converts compounds in the GC effluent to CO2 as required for function of the ion source. With cholesterol as test compound, the limits of quantitation were 175 pg and 0.00175 dpm injected. The accuracy achieved in analysis of five nonzero calibration standards and three quality control standards, using cholesterol-2,2,3,4,4,6-d6 as injection standard, was 100 +/- 11.8% with selected ion monitoring and 100 +/- 16% for radiochromatography. Respective values for interday precision were 1.0-3.2 and 22-32%. Application of GC/MS/AMS to a current topic of interest was demonstrated in a model metabolomic study in which cultured primary hepatocytes were given [(14)C]glucose and organic acids excreted into the culture medium were analyzed.

  17. 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.

  18. Numerical method for the estimation of column radial heterogeneity and of the actual column efficiency from tailing peak profiles.

    PubMed

    Miyabe, Kanji; Guiochon, Georges

    2011-01-01

    It is probably impossible to prepare high-performance liquid chromatography (HPLC) columns that have a completely homogeneous packing structure. Many reports in the literature show that the radial distributions of the mobile phase flow velocity and the local column efficiency are not flat, even in columns considered as good. A degree of radial heterogeneity seems to be a common property of all HPLC columns and an important source of peak tailing, which prevents the derivation of accurate information on chromatographic behavior from a straightforward analysis of elution peak profiles. This work reports on a numerical method developed to derive from recorded peak profiles the column efficiency at the column center, the degree of column radial heterogeneity, and the polynomial function that best represents the radial distributions of the flow velocity and the column efficiency. This numerical method was applied to two concrete examples of tailing peak profiles previously described. It was demonstrated that this numerical method is effective to estimate important parameters characterizing the radial heterogeneity of chromatographic columns.

  19. Method using gas chromatography to determine the molar flow balance for proton exchange membrane fuel cells exposed to impurities

    NASA Astrophysics Data System (ADS)

    Bender, G.; Angelo, M.; Bethune, K.; Dorn, S.; Thampan, T.; Rocheleau, R.

    An understanding of the potentially serious performance degradation effects that trace level contaminants can cause in proton exchange membrane fuel cells (PEMFCs) is crucial for the successful deployment of PEMFC for commercial applications. An experimental and analytic methodology is described that employs gas chromatography (GC) to accurately determine the concentration of impurity species in the fuel and oxidant streams of a PEMFC. In this paper we further show that the accurate determination of the contaminant concentrations at the anode and cathode inlets and outlets provides a means to quantify reactions of contaminants within the cell and to identify diffusive mass transport across the membrane. High data accuracy down to sub-ppm contaminant levels is required and was achieved by addressing several challenges pertaining to experimental setup and data analysis which are both discussed in detail. The application of the methodology is demonstrated using carbon monoxide and toluene which were injected into the cell at concentrations between 1 and 10 ppm and 20 and 60 ppm, respectively. Both impurities were observed to react in the fuel cell: carbon monoxide to carbon dioxide, and toluene to methylcyclohexane. For both contaminants closure of the molar flow balances to within 3% was achieved even at the low contaminant concentrations. This allowed the extent of both reactions at the applied operating conditions to be quantified. The presented methodology is shown to be a valuable tool for investigating the effects and reactions of trace contaminants in fuel cells and for providing critical insights into the mechanisms responsible for the associated performance degradation.

  20. Radial arm strike rail

    DOEpatents

    McKeown, Mark H.; Beason, Steven C.

    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.

  1. 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…

  2. Simultaneous clarification of Escherichia coli culture and purification of extracellularly produced penicillin G acylase using tangential flow filtration and anion-exchange membrane chromatography (TFF-AEMC).

    PubMed

    Orr, Valerie; Scharer, Jeno; Moo-Young, Murray; Honeyman, C Howie; Fenner, Drew; Crossley, Lisa; Suen, Shing-Yi; Chou, C Perry

    2012-07-01

    Downstream purification often represents the most cost-intensive step in the manufacturing of recombinant proteins since conventional purification processes are lengthy, technically complicated, and time-consuming. To address this issue, herein we demonstrated the simultaneous clarification and purification of the extracellularly produced recombinant protein by Escherichia coli using an integrated system of tangential flow filtration and anion exchange membrane chromatography (TFF-AEMC). After cultivation in a bench-top bioreactor with 1L working volume using the developed host/vector system for high-level expression and effective secretion of recombinant penicillin G acylase (PAC), the whole culture broth was applied directly to the established system. One-step purification of recombinant PAC was achieved based on the dual nature of membrane chromatography (i.e. microfiltration-sized pores and anion-exchange chemistry) and cross-flow operations. Most contaminant proteins in the extracellular medium were captured by the anion-exchange membrane and cells remained in the retentate, whereas extracellular PAC was purified and collected in the filtrate. The batch time for both cultivation and purification was less than 24h and recombinant PAC with high purity (19 U/mg), yield (72% recovery), and productivity (41 mg of purified PAC per liter of culture) was obtained. Due to the nature of the non-selective protein secretion system and the versatility of ion-exchange membrane chromatography, the developed system can be widely applied for effective production and purification of recombinant proteins.

  3. Triple acting radial seal

    SciTech Connect

    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.

  4. Comparison of the performance of forward fill/flush and reverse fill/flush flow modulation in comprehensive two-dimensional gas chromatography.

    PubMed

    Krupčík, Jan; Gorovenko, Roman; Špánik, Ivan; Sandra, Pat; Giardina, Matthew

    2016-09-30

    The performances of forward flow fill and flush (FFF) and of reverse flow fill and flush (RFF) in flow modulated comprehensive two-dimensional gas chromatography (GC×GC) using the same volume of the sampling channel have been studied and compared. Sample models include a reference mixture of hydrocarbons at low concentration, a petroleum reformate product and the essential oil of Rosa damascena Miller. The latter samples contain solutes in different concentrations but some up to 30% allowing to study overloading phenomena in detail. For solutes injected at low quantity, the performance of FFF and RFF is similar. For solutes present in a sample at high quantity, RFF guarantees less broadening and spreading resulting in better quantitation.

  5. New technique for treatment of postcatheterization radial artery pseudoaneurysm

    PubMed Central

    Pancholy, Samir B.; Kartashov, Dmitriy S.

    2016-01-01

    We report a new technique for treatment of radial artery pseudoaneurysm (RAP) caused by transradial access (TRA) for coronary angiography. Traditional extrinsic compression with radial flow cessation leads to a local milieu likely associated with an increase in probability of radial artery occlusion (RAO). Our technique involves obtaining ipsilateral radial artery access distal to the neck of the RAP followed by a prolonged sheath dwell time covering the neck of the RAP which allows the RAP sac to thrombose and maintains radial artery lumen patency. © 2016 The Authors. Catheterization and Cardiovascular Interventions Published by Wiley Periodicals, Inc. PMID:27527608

  6. Numerical Modeling of Heat-Mass Transfer in Radial Flow Plasma-Chemical Reactor with Multicomponent Kinetics CF4/02

    DTIC Science & Technology

    2002-08-23

    that the effect of CF3 adsorption on etching rate does not exceed 5%. In CF4/O2 plasma the oxygen reacts with CFx radicals preventing their...realized at the small gas flow rates (Table 1, gas flow rate 100 cm3/min). Here it is possible the effective control of etching rate by changing the...rates (100 cm3/min) where fluorine transfer is determined by a concentration diffusion to the wafer. Here it is possible the effective control of

  7. Radial gate evaluation: Olympus Dam, Colorado

    SciTech Connect

    1997-06-01

    The report presents a structural analysis of the radial gates of Olympus Dam in eastern Colorado. Five 20-foot wide by 17-foot high radial gates are used to control flow through the spillway at Olympus Dam. The spillway gates were designed in 1947. The gate arm assemblies consist of two separate wide flange beams, with a single brace between the arms. The arms pivot about a 4.0-inch diameter pin and bronze graphite-insert bushing. The pin is cantilevered from the pier anchor girder. The radial gates are supported by a pin bearing on a pier anchor birder bolted to the end of the concrete pier. The gates are operated by two-part wire rope 15,000-pound capacity hoise. Stoplog slots upstream of the radial gates are provided in the concrete piers. Selected drawings of the gates and hoists are located in appendix A.

  8. 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.

  9. Radial head fracture - aftercare

    MedlinePlus

    Elbow fracture - radial head - aftercare ... to 2 weeks. If you have a small fracture and your bones did not move around much, ... to see a bone doctor (orthopedic surgeon). Some fractures require surgery to: Insert pins and plates to ...

  10. 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.

  11. 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.

  12. Improving Peak Capacity in Fast On-Line Comprehensive Two-Dimensional Liquid Chromatography with Post First Dimension Flow-Splitting

    PubMed Central

    Filgueira, Marcelo R.; Huang, Yuan; Witt, Klaus; Castells, Cecilia; Carr, Peter W.

    2011-01-01

    The use of flow splitters between the two dimensions in on-line comprehensive two dimensional liquid chromatography (LC×LC) has not received very much attention in comparison to their use in GC×GC where they are quite common. In principle, splitting the flow after the first dimension column and performing on-line LC×LC on this constant fraction of the first dimension effluent should allow the two dimensions to be optimized almost independently. When there is no flow splitting any change in the first dimension flow rate has an immediate impact on the second dimension. With a flow splitter one could for example double the flow rate into the first dimension column and do a 1:1 flow split without changing the sample loop size or the sampler’s collection time. Of course, the sensitivity would be diminished but this can be partially compensated by use of a larger injection; this will likely only amount to a small price to pay for this increased resolving power and system flexibility. Among other benefits, we found a 2-fold increase in the corrected 2D peak capacity and the number of observed peaks for a 15 min analysis time by using a post first dimension flow splitter. At a fixed analysis time this improvement results primarily from an increase in the gradient time resulting from the reduced system re-equilibration time and to a smaller extent it is due to the increased peak capacity achieved by full optimization of the first dimension. PMID:22017622

  13. 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 (GC×GC). 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.

  14. 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 39 min, 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 0.2-2.0 μg/kg given by signal-noise ratio ≥3 (S/N) and the limits of quantification (LOQ, S/N≥10) ranged between 0.5 μg/kg and 10 μg/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.

  15. Development and validation of a turbulent flow chromatography and tandem mass spectrometry method for the quantitation of methotrexate and its metabolites 7-hydroxy methotrexate and DAMPA in serum.

    PubMed

    Schofield, Ryan C; Ramanathan, Lakshmi V; Murata, Kazunori; Grace, Marie; Fleisher, Martin; Pessin, Melissa S; Carlow, Dean C

    2015-10-01

    A rapid and simple turbulent flow liquid chromatography (TFC-LC) method implementing positive heated electrospray ionization (HESI) for the accurate and precise determination of methotrexate (MTX), 7-hydroxy methotrexate (7-OH MTX), and 4-amino-4-deoxy-N(10)-methylpteroic acid (DAMPA) concentrations in serum was developed. MTX was isolated from serum samples (100μL) after protein precipitation with methanol containing formic acid and internal standard (MTX-D3) followed by centrifugation. The supernatant was injected into the turbulent flow liquid chromatography which is followed by electrospray positive ionization tandem mass spectrometry (TFC-LC-MS/MS) and quantified using a six-point calibration curve. For MTX and DAMPA the assays were linear from 10 to 1000nmol/L and for 7-OH MTX from 20 to 2000nmol/L. Dilutions of 10, 100 and 1000-fold were validated giving a clinically reportable range of 10nmol/L to 5×10(5)nmol/L. Within-day and between-day precisions at concentrations spanning the analytical measurement ranges were less than 10% for all three analytes. MTX, DAMPA and 7-OH MTX were sufficiently stable under all relevant analytical conditions. No significant matrix effect was observed during the method validation. The TFC-LC-MS/MS MTX method was also compared with three other clinically validated MTX assays: a dihydrofolate reductase (DHFR) inhibition assay, an immunoassay based on fluorescence polarization and a previously developed LC-MS/MS assay.

  16. On-line coupling of macroporous resin column chromatography with direct analysis in real time mass spectrometry utilizing a surface flowing mode sample holder.

    PubMed

    Zeng, Shanshan; Wang, Lu; Chen, Teng; Qu, Haibin

    2014-02-06

    A surface flowing mode sample holder was designed as an alternative sampling strategy for direct analysis in real time mass spectrometry (DART-MS). With the sample holder, the on-line coupling of macroporous resin column chromatography with DART-MS was explored and the new system was employed to monitor the column chromatography elution process of Panax notoginseng. The effluent from macroporous resin column was first diluted and mixed with a derivatization reagent on-line, and the mixture was then directly transferred into the ionization region of DART-MS by the sample holder. Notoginsenosides were methylated and ionized in a metastable helium gas stream, and was introduced into MS for detection. The on-line system showed reasonable repeatability with a relative standard deviation of 12.3% for the peak area. Three notoginsenosides, i.e. notoginsenoside R1, ginsenoside Rb1 and ginsenoside Rg1, were simultaneously determined during the eluting process. The alteration of the chemical composition in the effluent was accurately identified in 9 min, agreeing well with the off-line analysis. The presented technique is more convenient compared to the traditional UPLC method. These results suggest that the surface flowing mode DART-MS has a good potential for the on-line process monitoring in the pharmaceutical industry.

  17. Characterizing pressure issues due to turbulent flow in tubing, in ultra-fast chiral supercritical fluid chromatography at up to 580bar.

    PubMed

    Berger, Terry A

    2016-12-02

    It has been widely suggested that the outlet pressure be changed to maintain constant density ("isopycnic" conditions) when comparing the kinetic performance of different columns in supercritical fluid chromatography (SFC). However, at high flow rates, flow in the tubing is turbulent, causing large extra-column pressure drops that limit options for changing outlet pressure. Some of these pressure drops occur before and some after the column, obscuring the actual column inlet and outlet pressures. In this work, a 4.6×100mm, 1.8μm R,R-Whelk-O1 column was used with low dispersion LD (120μm) plumbing to generate sub-1min chiral separations. However, the optimum, or near optimum, flow rate was 5mL-min(-1), producing a system pressure of 580bar (with 40% methanol, outlet pressure 120bar). Both the flow rate and pump pressure required were near the limits of the instrument, and significantly exceeded the capability of many other SFC's. Extra-column pressure drops (ΔPec) were as high as 200bar, caused mostly by turbulent flow in the tubing. The ΔPec increased by more than the square of the flow rate. Reynolds Numbers (Re) were calculated for tubing as a function of flow rate between 100 and 400bar and 5-20% methanol in CO2, and 40°-60°C. This represents the most extensive analysis of turbulence in tubing in the SFC literature. Flow in 120μm ID tubing was calculated to be laminar below 1.0mL-min(-1), mostly transitional up to 2.5mL-min(-1) and virtually always turbulent at 3mL-min(-1) and higher. Flow in 170μm tubing is turbulent at lower flows but generates half the ΔPec due to the lower mobile phase linear velocity. The results suggest that, while sub-minute chromatograms are easily generated, 4.6mm columns are not very user friendly for use with sub-2μm packings. The high flow rates required just to reach optimum result in high ΔPec generated by the tubing, causing uncertainty in the true column inlet, outlet, and average column pressure/density. When

  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. Radial wedge flange clamp

    DOEpatents

    Smith, Karl H.

    2002-01-01

    A radial wedge flange clamp comprising a pair of flanges each comprising a plurality of peripheral flat wedge facets having flat wedge surfaces and opposed and mating flat surfaces attached to or otherwise engaged with two elements to be joined and including a series of generally U-shaped wedge clamps each having flat wedge interior surfaces and engaging one pair of said peripheral flat wedge facets. Each of said generally U-shaped wedge clamps has in its opposing extremities apertures for the tangential insertion of bolts to apply uniform radial force to said wedge clamps when assembled about said wedge segments.

  20. Radially uniform electron source

    NASA Technical Reports Server (NTRS)

    Mccomas, D.; Bame, S. J.

    1982-01-01

    A thermionic electron source capable of producing uniform count rates in a number of channel electron multipliers simultaneously was required for conditioning multipliers for an extended space mission. It was found that a straight tungsten filament in the center of a cylindrically symmetric geometry surrounded by an array of multipliers emits a radially asymmetric distribution of electrons that changes with time. A source was developed which successfully produces a time-independent radially uniform distribution of electrons by moving the filament out of the direct line of sight and replacing it with a centrally located electron 'cloud.'

  1. Approximate theory for radial filtration/consolidation

    SciTech Connect

    Tiller, F.M.; Kirby, J.M.; Nguyen, H.L.

    1996-10-01

    Approximate solutions are developed for filtration and subsequent consolidation of compactible cakes on a cylindrical filter element. Darcy`s flow equation is coupled with equations for equilibrium stress under the conditions of plane strain and axial symmetry for radial flow inwards. The solutions are based on power function forms involving the relationships of the solidosity {epsilon}{sub s} (volume fraction of solids) and the permeability K to the solids effective stress p{sub s}. The solutions allow determination of the various parameters in the power functions and the ratio k{sub 0} of the lateral to radial effective stress (earth stress ratio). Measurements were made of liquid and effective pressures, flow rates, and cake thickness versus time. Experimental data are presented for a series of tests in a radial filtration cell with a central filter element. Slurries prepared from two materials (Microwate, which is mainly SrSO{sub 4}, and kaolin) were used in the experiments. Transient deposition of filter cakes was followed by static (i.e., no flow) conditions in the cake. The no-flow condition was accomplished by introducing bentonite which produced a nearly impermeable layer with negligible flow. Measurement of the pressure at the cake surface and the transmitted pressure on the central element permitted calculation of k{sub 0}.

  2. 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)

  3. Direct analysis of prostaglandin-E2 and -D2 produced in an inflammatory cell reaction and its application for activity screening and potency evaluation using turbulent flow chromatography liquid chromatography-high resolution mass spectrometry.

    PubMed

    Shin, Jeong-Sook; Peng, Lei; Kang, Kyungsu; Choi, Yongsoo

    2016-09-09

    Direct analysis of prostaglandin-E2 (PGE2) and -D2 (PGD2) produced from a RAW264.7 cell-based reaction was performed by liquid chromatography high-resolution mass spectrometry (LC-HRMS), which was online coupled with turbulent flow chromatography (TFC). The capability of this method to accurately measure PG levels in cell reaction medium containing cytokines or proteins as a reaction byproduct was cross-validated by two conventional methods. Two methods, including an LC-HRMS method after liquid-liquid extraction (LLE) of the sample and a commercial PGE2 enzyme-linked immunosorbent assay (ELISA), showed PGE2 and/or PGD2 levels almost similar to those obtained by TFC LC-HRMS over the reaction time after LPS stimulation. After the cross-validation, significant analytical throughputs, allowing simultaneous screening and potency evaluation of 80 natural products including 60 phytochemicals and 20 natural product extracts for the inhibition of the PGD2 produced in the cell-based inflammatory reaction, were achieved using the TFC LC-HRMS method developed. Among the 60 phytochemicals screened, licochalcone A and formononetin inhibited PGD2 production the most with IC50 values of 126 and 151nM, respectively. For a reference activity, indomethacin and diclofenac were used, measuring IC50 values of 0.64 and 0.21nM, respectively. This method also found a butanol extract of Akebia quinata Decne (AQ) stem as a promising natural product for PGD2 inhibition. Direct and accurate analysis of PGs in the inflammatory cell reaction using the TFC LC-HRMS method developed enables the high-throughput screening and potency evaluation of as many as 320 samples in less than 48h without changing a TFC column.

  4. Method for the quantification of vanadyl porphyrins in fractions of crude oils by High Performance Liquid Chromatography-Flow Injection-Inductively Coupled Plasma Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Wandekoken, Flávia G.; Duyck, Christiane B.; Fonseca, Teresa C. O.; Saint'Pierre, Tatiana D.

    2016-05-01

    High performance liquid chromatography hyphenated by flow injection to inductively coupled plasma mass spectrometry (HPLC-FI-ICP-MS) was used to investigate V linked to porphyrins present in fractions of crude oil. First, the crude oil sample was submitted to fractionation by preparative liquid chromatography with UV detection, at the porphyrin Soret band wavelength (400 nm). The obtained porphyrin fractions were then separated in a 250 mm single column, in the HPLC, and eluted with different mobile phases (methanol or methanol:toluene (80:20; v:v)). The quantification of V-porphyrins in the fractions eluted from HPLC was carried out by online measuring the 51V isotope in the ICP-MS, against vanadyl octaethylporphine standard solutions (VO-OEP), prepared in the same solvent as the mobile phase, and injected post-column directly into the plasma. A 20 μg L- 1 Ge in methanol was used as internal standard for minimizing non-spectral interference, such as short-term variations due to injection. The mathematical treatment of the signal based on Fast Fourier Transform smoothing algorithm was employed to improve the precision. The concentrations of V as V-porphyrins were between 2.7 and 11 mg kg- 1 in the fractions, which were close to the total concentration of V in the porphyrin fractions of the studied crude oil.

  5. A direct comparison of the performance of ground, beaded and silica-grafted MIPs in HPLC and turbulent flow chromatography applications.

    PubMed

    Fairhurst, Robert E; Chassaing, Christophe; Venn, Richard F; Mayes, Andrew G

    2004-12-15

    Spherical molecularly imprinted polymers (MIPs) specific to the beta-blocker propranolol have been synthesised using two different approaches and compared to traditional ground monolithic MIPs in HPLC and TFC applications. TFC is a LC technique used for rapid extraction of compounds directly from complex matrices. It can be easily coupled to HPLC and MS for automation of an extraction/analysis procedure. Spherical MIP beads were produced using a suspension polymerisation technique and silica/MIP composite beads by grafting MIP to spherical silica particles using a surface-bound initiator species. Synthesis of both beaded and silica-grafted MIPs was more practical than using the traditional grinding method and yields of spherical particles of the required size between 80 and 100% were routinely achieved. Under HPLC conditions, beaded and ground MIP materials showed a degree of chiral separation for all of the nine beta-blockers tested. The beaded MIP, however, showed much better flow properties and peak shape than the ground material. Silica-grafted MIP showed some separation in five of the drugs and a large improvement in peak shape and analysis times compared with both ground and beaded MIPs. The materials prepared were also used in extraction columns for Turbulent Flow Chromatography (TFC). Although no imprinting effect was observed under typical TFC conditions, beaded polymer materials showed promise for use as TFC extraction columns due to the good flow properties and clean extracts obtained.

  6. 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.

  7. 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

  8. Radial inflow gas turbine engine with advanced transition duct

    DOEpatents

    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).

  9. Determination of perfluorinated chemicals in food and drinking water using high-flow solid-phase extraction and ultra-high performance liquid chromatography/tandem mass spectrometry.

    PubMed

    Chang, Ying-Chia; Chen, Wen-Ling; Bai, Fang-Yu; Chen, Pau-Chung; Wang, Gen-Shuh; Chen, Chia-Yang

    2012-01-01

    For this study, we developed methods of determining ten perfluorinated chemicals in drinking water, milk, fish, beef, and pig liver using high-flow automated solid-phase extraction (SPE) and ultra-high performance liquid chromatography/tandem mass spectrometry. The analytes were separated on a core-shell Kinetex C18 column. The mobile phase was composed of methanol and 10-mM N-methylmorpholine. Milk was digested with 0.5 N potassium hydroxide in Milli-Q water, and was extracted with an Atlantic HLB disk to perform automated SPE at a flow rate ranged from 70 to 86 mL/min. Drinking water was directly extracted by the SPE. Solid food samples were digested in alkaline methanol and their supernatants were diluted and also processed by SPE. The disks were washed with 40% methanol/60% water and then eluted with 0.1% ammonium hydroxide in methanol. Suppression of signal intensity of most analytes by matrixes was lower than 50%; it was generally lower in fish and drinking water but higher in liver. Most quantitative biases and relative standard deviations were lower than 15%. The limits of detection for most analytes were sub-nanograms per liter for drinking water and sub-nanograms per gram for solid food samples. This method greatly shortened the time and labor needed for digestion, SPE, and liquid chromatography. This method has been applied to analyze 14 types of food samples. Perfluorooctanoic acid was found to be the highest among the analytes (median at 3.2-64 ng/g wet weight), followed by perfluorodecanoic acid (0.7-25 ng/g) and perfluorododecanoic acid (0.6-15 ng/g).

  10. Effect of radial flow on two particle correlations with identified triggers at intermediate pT in p-Pb collisions at √{sNN} = 5.02 TeV

    NASA Astrophysics Data System (ADS)

    Sarkar, Debojit; Choudhury, Subikash; Chattopadhyay, Subhasis

    2016-09-01

    Results from two-particle correlation between identified triggers (pions (π±), protons (p / p bar)) and un-identified charged particles at intermediate transverse momentum (pT) in p-Pb collisions at √{sNN} = 5.02 TeV have been presented. The events generated from a hybrid Monte-Carlo event generator, EPOS 3.107 that implements a flux-tube initial conditions followed by event by event 3+1D viscous hydrodynamical evolution, have been analyzed to calculate two-dimensional correlation functions in Δη- Δϕ. The strength of angular correlations at small relative angles (jet-like correlations), quantified in terms of near-side jet-like per-trigger yield has been calculated as a function of the event multiplicity. The yield associated with pion triggers exhibit negligible multiplicity dependence, while the proton-triggered yield shows a gradual suppression from low to high multiplicity events. In small collision systems like p-Pb where jet modification is expected to be less dominant, the observed suppression may be associated with the hydrodynamical evolution of the bulk system that generates an outward radial flow. Analogous measurements in Au-Au collisions at RHIC energy have shown a hint of dilution in proton-triggered correlation at its highest multiplicity suggesting that the soft physics processes in p-Pb and heavy ion collisions may have qualitative similarity.

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

    PubMed

    Schwienheer, C; Merz, J; Schembecker, G

    2015-04-17

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

  12. 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.

  13. Radial pressure flange seal

    DOEpatents

    Batzer, Thomas H.; Call, Wayne R.

    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.

  14. 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.

  15. 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.

  16. Antiproton compression and radial measurements

    SciTech Connect

    Andresen, G. B.; Bowe, P. D.; Hangst, J. S.; Bertsche, W.; Butler, E.; Charlton, M.; Humphries, A. J.; Jenkins, M. J.; Joergensen, L. V.; Madsen, N.; Werf, D. P. van der; Bray, C. C.; Chapman, S.; Fajans, J.; Povilus, A.; Wurtele, J. S.; Cesar, C. L.; Lambo, R.; Silveira, D. M.; Fujiwara, M. C.

    2008-08-08

    Control of the radial profile of trapped antiproton clouds is critical to trapping antihydrogen. We report detailed measurements of the radial manipulation of antiproton clouds, including areal density compressions by factors as large as ten, achieved by manipulating spatially overlapped electron plasmas. We show detailed measurements of the near-axis antiproton radial profile, and its relation to that of the electron plasma. We also measure the outer radial profile by ejecting antiprotons to the trap wall using an octupole magnet.

  17. 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.

  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.

  19. 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 (≈7 mL min(-1)) compatible with the qMS system used. Six-point calibration curves, over the range 1, 5, 10, 20, 50, 100 mg L(-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 5 mg L(-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.

  20. Automation of flow injection gas diffusion-ion chromatography for the nanomolar determination of methylamines and ammonia in seawater and atmospheric samples

    PubMed Central

    Gibb, Stuart W.; Wood, John W.; Fauzi, R.; Mantoura, C.

    1995-01-01

    The automation and improved design and performance of Flow Injection Gas Diffusion-Ion Chromatography (FIGD-IC), a novel technique for the simultaneous analysis of trace ammonia (NH3) and methylamines (MAs) in aqueous media, is presented. Automated Flow Injection Gas Diffusion (FIGD) promotes the selective transmembrane diffusion of MAs and NH3 from aqueous sample under strongly alkaline (pH > 12, NaOH), chelated (EDTA) conditions into a recycled acidic acceptor stream. The acceptor is then injected onto an ion chromatograph where NH3 and the MAs are fully resolved as their cations and detected conductimetrically. A versatile PC interfaced control unit and data capture unit (DCU) are employed in series to direct the selonoid valve switching sequence, IC operation and collection of data. Automation, together with other modifications improved both linearily (R2 > 0.99 MAs 0-100 nM, NH3 0-1000 nM) and precision (<8%) of FIGD-IC at nanomolar concentrations, compared with the manual procedure. The system was successfully applied to the determination of MAs and NH3 in seawater and in trapped particulate and gaseous atmospheric samples during an oceanographic research cruise. PMID:18925047

  1. Characterization of vitamin D3 metabolites using continuous-flow fast atom bombardment tandem mass spectrometry and high-performance liquid chromatography.

    PubMed

    Yeung, B; Vouros, P; Reddy, G S

    1993-08-13

    A mass spectrometric method for the detection of vitamin D3 metabolites is described. This method involves the derivatization of the metabolites by cycloaddition with 4-phenyl-1,2,4-triazoline-3,5-dione, followed by their characterization by continuous-flow fast atom bombardment (CF-FAB) tandem mass spectrometry (MS-MS) and high-performance liquid chromatography (HPLC). Using HPLC, this derivatization has been shown to increase the UV detectability of 25-hydroxyvitamin D3 by about 5-fold. The FAB spectra of the adducts are dominated by peaks corresponding to a protonated molecule and a fragment ion derived in part from the loss of the side chain. Multiple reaction monitoring (MRM) of this transition by MS-MS may be utilized for trace level analysis of vitamin D metabolites. Sample introduction by flow injection yields detection limits in the low nanogram to high picogram range, whereas the use of on-line capillary LC has been found to decrease the detection limits to the low picogram level.

  2. 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.

  3. 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.

  4. 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

  5. Computer Simulation of Radial Immunodiffusion

    PubMed Central

    Trautman, Rodes

    1972-01-01

    Theories of diffusion with chemical reaction are reviewed as to their contributions toward developing an algorithm needed for computer simulation of immunodiffusion. The Spiers-Augustin moving sink and the Engelberg stationary sink theories show how the antibody-antigen reaction can be incorporated into boundary conditions of the free diffusion differential equations. For this, a stoichiometric precipitate was assumed and the location of precipitin lines could be predicted. The Hill simultaneous linear adsorption theory provides a mathematical device for including another special type of antibody-antigen reaction in antigen excess regions of the gel. It permits an explanation for the lowered antigen diffusion coefficient, observed in the Oudin arrangement of single linear diffusion, but does not enable prediction of the location of precipitin lines. The most promising mathematical approach for a general solution is implied in the Augustin alternating cycle theory. This assumes the immunodiffusion process can be evaluated by alternating computation cycles: free diffusion without chemical reaction and chemical reaction without diffusion. The algorithm for the free diffusion update cycle, extended to both linear and radial geometries, is given in detail since it was based on gross flow rather than more conventional expressions in terms of net flow. Limitations on the numerical integration process using this algorithm are illustrated for free diffusion from a cylindrical well. PMID:4629869

  6. 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.

  7. 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.

  8. Neuere Chromatographie

    NASA Astrophysics Data System (ADS)

    Hostettmann, K.

    1983-04-01

    Besides high-performance liquid chromatography (HPLC) which is now a well-established and currently used technique, several emerging methods for the isolation and separation of natural products are receiving considerable attention. Centrifugal thin-layer chromatography is a very rapid technique, but limited in resolution. Of special interest are the recently developed support-free liquid-liquid chromatography methods such as droplet counter-current chromatography (DCCC) and rotation locular counter-current chromatography (RLCC). This latter method was applied to the separation of the enantiomers of (±)-norephedrine.

  9. 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.

  10. Comparison of turbulent-flow chromatography with automated solid-phase extraction in 96-well plates and liquid-liquid extraction used as plasma sample preparation techniques for liquid chromatography-tandem mass spectrometry.

    PubMed

    Zimmer, D; Pickard, V; Czembor, W; Müller, C

    1999-08-27

    Turbulent flow chromatography (TFC) combined with the high selectivity and sensitivity of tandem mass spectrometry (MS-MS) is a new technique for the fast direct analysis of drugs from crude plasma. TFC in the 96-well plate format reduces significantly the time required for sample clean-up in the laboratory. For example, for 100 samples the workload for a technician is reduced from about 8 h by a manual liquid-liquid extraction (LLE) assay to about 1 h in the case of TFC. Sample clean-up and analysis are performed on-line on the same column. Similar chromatographic performance and validation results were achieved using HTLC Turbo-C18 columns (Cohesive Technologies) and Oasis HLB extraction columns (Waters). One 96-well plate with 96 plasma samples is analyzed within 5.25 h, corresponding to 3.3 min per sample. Compared to this LLE and analysis of 96 samples takes about 16 h. Two structurally different and highly protein bound compounds, drug A and drug B, were analyzed under identical TFC conditions and the assays were fully validated for the application to toxicokinetics studies (compliant with Good Laboratory Practices-GLP). The limit of quantitation was 1.00 microg/l and the linear working range covered three orders of magnitude for both drugs. In the case of drug A the quality of analysis by TFC was similar to the reference LLE assay and slightly better than automated solid-phase extraction in 96-well plates. The accuracy was -3.1 to 6.7% and the precision was 3.1 to 6.8% in the case of drug A determined for dog plasma by TFC-MS-MS. For drug B the accuracy was -3.7 to 3.5% and the precision was 1.6 to 5.4% for rat plasma, which is even slightly better than what was achieved with the validated protein precipitation assay.

  11. Revascularization using satellite vein after radial artery harvested for coronary artery bypass grafting.

    PubMed

    Gon, Shigeyoshi; Yoshida, Shigehiko; Sanae, Tsutomu; Takahashi, Tamami; Inada, Eiichi

    2006-06-01

    The radial artery has been increasingly used for coronary artery bypass grafting and has excellent long-term patency rates. Hand claudication is one of the adverse effects after radial artery harvest. We reconstructed a radial artery using the satellite vein to prevent hand claudication. Pulsating blood flow at 35 cm/sec was evaluated using color Doppler echocardiography three months after surgery. This method makes it possible to use a radial artery in patients with a positive Allen test.

  12. Zonal rate model for stacked membrane chromatography part II: characterizing ion-exchange membrane chromatography under protein retention conditions.

    PubMed

    Francis, Patrick; von Lieres, Eric; Haynes, Charles

    2012-03-01

    The Zonal Rate Model (ZRM) has previously been shown to accurately account for contributions to elution band broadening, including external flow nonidealities and radial concentration gradients, in ion-exchange membrane (IEXM) chromatography systems operated under nonbinding conditions. Here, we extend the ZRM to analyze and model the behavior of retained proteins by introducing terms for intra-column mass transfer resistances and intrinsic binding kinetics. Breakthrough curve (BTC) data from a scaled-down anion-exchange membrane chromatography module using ovalbumin as a model protein were collected at flow rates ranging from 1.5 to 20 mL min(-1). Through its careful accounting of transport nonidealities within and external to the membrane stack, the ZRM is shown to provide a useful framework for characterizing putative protein binding mechanisms and models, for predicting BTCs and complex elution behavior, including the common observation that the dynamic binding capacity can increase with linear velocity in IEXM systems, and for simulating and scaling separations using IEXM chromatography. Global fitting of model parameters is used to evaluate the performance of the Langmuir, bi-Langmuir, steric mass action (SMA), and spreading-type protein binding models in either correlating or fundamentally describing BTC data. When combined with the ZRM, the bi-Langmuir, and SMA models match the chromatography data, but require physically unrealistic regressed model parameters to do so. In contrast, for this system a spreading-type model is shown to accurately predict column performance while also providing a realistic fundamental explanation for observed trends, including an observed increase in dynamic binding capacity with flow rate.

  13. Dielectrokinetic chromatography devices

    DOEpatents

    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.

  14. 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 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.

  15. Simultaneous determination of some food additives in soft drinks and other liquid foods by flow injection on-line dialysis coupled to high performance liquid chromatography.

    PubMed

    Kritsunankul, Orawan; Jakmunee, Jaroon

    2011-06-15

    Flow injection on-line dialysis was developed for sample pretreatment prior to the simultaneous determination of some food additives by high performance liquid chromatography (FID-HPLC). A liquid sample or mixed standard solution (900 μL) was injected into a donor stream (5%, w/v, sucrose) of FID system and was pushed further through a dialysis cell, while an acceptor solution (0.025 mol L(-1) phosphate buffer, pH 3.75) was held in the opposite side of the dialysis membrane. The dialysate was then flowed to an injection loop of the HPLC valve, where it was further injected into the HPLC system and analyzed under isocratic reverse-phase HPLC conditions and UV detection (230 nm). The order of elution of five food additives was acesulfame-K, saccharin, caffeine, benzoic acid and sorbic acid, respectively, with the analysis time of 14 min. On-line dialysis and HPLC analysis could be performed in parallel, providing sample throughput of 4.3h(-1). Dialysis efficiencies of five food additives were in ranges of 5-11%. Linear calibration graphs were in ranges of 10-100 mg L(-1) for acesulfame-K and saccharin, 10-250 mg L(-1) for benzoic acid and 10-500 mg L(-1) for caffeine and sorbic acid. Good precisions (RSD<5%) for all the additives were obtained. The proposed system was applied to soft drink and other liquid food samples. Acceptable percentage recoveries could be obtained by appropriate dilution of the sample before injecting into the system. The developed system has advantages of high degrees of automation for sample pretreatment, i.e., on-line sample separation and dilution and low consumption of chemicals and materials.

  16. On-line pretreatment and determination of parabens in cosmetic products by combination of flow injection analysis, solid-phase extraction and micellar electrokinetic chromatography.

    PubMed

    Han, Fang; He, You-Zhao; Yu, Chang-Zhu

    2008-02-15

    A convenient and automated method for on-line pretreatment and determination of three parabens (i.e. methyl, ethyl and propyl p-hydroxybenzoate) in cosmetic products is proposed by using flow injection analysis (FIA), solid-phase extraction (SPE) and micellar electrokinetic chromatography (MEKC). An improved split-flow interface is used to couple SPE on C(8)-bonded silica with MEKC separation, which can avoid running buffer contamination and reduce buffer consumption, especially, containing expensive reagents. The analytes are loaded onto a C(8) column at 0.6 mL/min for 60s and eluted with a mixed eluent of 40% (v/v) 10 mmol/L sodium tetraborate buffer (pH 9.3) and 60% (v/v) ethanol at 0.75 mL/min. The MEKC separation is accomplished with a running buffer of 20 mmol/L sodium tetraborate (pH 9.3) containing 100 mmol/L sodium dodecyl sulfate (SDS) at 15 kV. For butyl p-hydroxybenzoate did not be detected in the cosmetic products, it was used as an internal standard (IS) added into the real samples. This FIA-SPE-MEKC method using IS allows the sample separation within 12 min and the sample throughput of five samples per hour with the relative standard deviation (R.S.D.) less than 2.3% (n=5). The limits of detection (LOD) are in the range from 0.07 to 0.1 microg/mL (S/N=3 and n=11). The proposed method has been used to determine three parabens in real cosmetic products satisfactorily.

  17. 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

    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.

  18. 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).

  19. 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

  20. Evaluation of a direct injection nebulizer interface for flow injection analysis and high performance liquid chromatography with inductively coupled plasma-atomic emission spectroscopic detection

    SciTech Connect

    LaFreniere, K.E.

    1986-06-01

    A direct injection nebulizer (DIN) was designed, developed, and evaluated to determine its potential utilization as an effective interface for flow injection analysis (FIA) and high performance liquid chromatography (HPLC) coupled with inductively coupled plasma-atomic emission spectroscopic detection. The analytical figures of merit for the DIN when used as an interface for FIA-ICP-AES were found to be comparable to or better than those obtained with conventional pneumatic nebulization in terms of limits of detection (LODs), reproducibility, linearity, and interelement effects. Stable plasma operation was maintained for the DIN sample introduction of a variety of pure organic solvents, including acetonitrile, methanol, methylisobutylketone, and pyridine. The HPLC-DIN-ICP-AES facility was specifically applied for the speciation of inorganic and organometallic species contained in synthetic mixtures, vanilla extracts, and a variety of energy-related materials, such as shale oil process water, coal extracts, shale oil, crude oil, and an SRC II. Suggestions for future research are also considered. 227 refs., 44 figs., 15 tabs.

  1. Reversed phase liquid chromatography hyphenated to continuous flow-extractive desorption electrospray ionization-mass spectrometry for analysis and charge state manipulation of undigested proteins.

    PubMed

    Li, Li; Yang, Samuel H; Vidova, Veronika; Rice, Elisa M; Wijeratne, Aruna B; Havlíček, Vladimír; Schug, Kevin A

    2015-01-01

    The application of continuous flow-extractive desorption electrospray ionization (CF-EDESI), an ambient ionization source demonstrated previously for use with intact protein analysis, is expanded here for the coupling of reversed phase protein separations to mass spectrometry. This configuration allows the introduction of charging additives to enhance detection without affecting the chromatographic separation mechanism. Two demonstrations of the advantages of CF-EDESI are presented in this work. First, a proof-of- principle is presented to demonstrate the applicability of hyphenation of liquid chromatography (LC) to CF- EDESI. LC-CF-EDESI-MS has good sensitivity compared to LC-electrospray ionization (ESI)-mass spectrometry. Second, the supercharging mechanism investigated in CF-EDESI provides an insight into a highly debated supercharging process in ESI. The results indicate that the mechanism of protein charging seen in HPLC-CF-EDESI is different from supercharging phenomena in conventional ESI. The surface tension mechanism and binding mechanism may both contribute to protein supercharging in ESI.

  2. Angiologic observations following radial artery flap elevation: a case report.

    PubMed

    Ciria-Lloréns, G; Gómez-Cía, T; Talegón-Meléndez, A

    1998-01-01

    Since the introduction of the radial forearm flap in 1981, its inherent vascular morbidity in sacrificing the radial artery has been strongly criticized. In the present paper, a case report is presented where postoperative angiography showed an important contribution of the anterior interosseous artery to hand vascularity two years after raising a reverse flow distally based pedicle radial forearm flap for dorsal hand resurfacing. In order to analyze this finding, further vascular investigations using Color Duplex Imaging examinations for quantitative flow measurements comparing blood flow rates in both right and left forearm arteries were carried out in this patient. Contrary to expectations, results from vascular examinations revealed that overall blood flow in donor forearm arteries was greater than in the contralateral forearm, the anterior interosseous artery showing the greatest difference in blood flow. These data seem to indicate that another major vascular axis based on the anterior interosseous artery develops after removing the radial artery when harvesting the radial forearm flap and that global arterial inflow to the hand is not impaired.

  3. Design and performance of a new continuous-flow sample-introduction system for flame infrared-emission spectrometry: Applications in process analysis, flow injection analysis, and ion-exchange high-performance liquid chromatography.

    PubMed

    Lam, C K; Zhang, Y; Busch, M A; Busch, K W

    1993-06-01

    A new sample introduction system for the analysis of continuously flowing liquid streams by flame infrared-emission (FIRE) spectrometry has been developed. The system uses a specially designed purge cell to strip dissolved CO(2) from solution into a hydrogen gas stream that serves as the fuel for a hydrogen/air flame. Vibrationally excited CO(2) molecules present in the flame are monitored with a simple infrared filter (4.4 mum) photometer. The new system can be used to introduce analytes as a continuous liquid stream (process analysis mode) or on a discrete basis by sample injection (flow injection analysis mode). The key to the success of the method is the new purge-cell design. The small internal volume of the cell minimizes problems associated with purge-cell clean-out and produces sharp, reproducible signals. Spent analytical solution is continuously drained from the cell, making cell disconnection and cleaning between samples unnecessary. Under the conditions employed in this study, samples could be analyzed at a maximum rate of approximately 60/h. The new sample introduction system was successfully tested in both a process analysis- and a flow injection analysis mode for the determination of total inorganic carbon in Waco tap water. For the first time, flame infrared-emission spectrometry was successfully extended to non-volatile organic compounds by using chemical pretreatment with peroxydisulfate in the presence of silver ion to convert the analytes into dissolved carbon dioxide, prior to purging and detection by the FIRE radiometer. A test of the peroxydisulfate/Ag(+) reaction using six organic acids and five sugars indicated that all 11 compounds were oxidized to nearly the same extent. Finally, the new sample introduction system was used in conjunction with a simple filter FIRE radiometer as a detection system in ion-exchange high-performance liquid chromatography. Ion-exchange chromatograms are shown for two aqueous mixtures, one containing six organic

  4. 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…

  5. Turbine with radial acting seal

    SciTech Connect

    Eng, Darryl S; Ebert, Todd A

    2016-11-22

    A floating brush seal in a rim cavity of a turbine in a gas turbine engine, where the floating brush seal includes a seal holder in which the floating brush seal floats, and a expandable seal that fits within two radial extending seal slots that maintains a seal with radial displacement of the floating brush seal and the seal holder.

  6. Radial systems of dark globules

    SciTech Connect

    Gyul'budagyn, A.L.

    1986-03-01

    The author gives examples of radial systems consisting of dark globules and ''elephant trunks''. Besides already known systems, which contain hot stars at their center, data are given on three radial systems of a new kind, at the center of which there are stars of spectral types later than B. Data are given on 32 globules of radial systems of the association Cep OB2. On the basis of the observational data, it is concluded that at least some of the isolated Bok globules derive from elephant trunks and dark globules forming radial systems around hot stars. It is also suggested that the two molecular clouds situated near the Rosette nebula and possessing velocities differing by ca 20 km/sec from the velocity of the nebula could have been ejected in opposite directions from the center of the nebula. One of these clouds consists of dark globules forming the radial system of the Rosette nebula.

  7. Crustal radial anisotropy beneath Cameroon from ambient noise tomography

    NASA Astrophysics Data System (ADS)

    Ojo, Adebayo Oluwaseun; Ni, Sidao; Li, Zhiwei

    2017-01-01

    To increase the understanding of crustal deformation and crustal flow patterns due to tectonic processes in Cameroon, we study the lateral variability of the crustal isotropic velocity and radial anisotropy estimated using Ambient Noise Tomography (ANT). Rayleigh and Love wave Noise Correlation Functions (NCFs) were retrieved from the cross-correlation of seismic ambient noise data recorded in Cameroon, and phase velocities at periods of 8 to 30 s were measured to perform surface wave tomography. Joint inversion of Rayleigh and Love wave data for isotropic velocity models could not fit the observed dispersions simultaneously. We attribute the Love-Rayleigh discrepancy to the presence of radial anisotropy in the crust and estimated its magnitude. Our 3-D radial anisotropic model reveals the spatial variation of strong to weak positive (Vsh > Vsv) and negative (Vsv > Vsh) radial anisotropy in the crust. We observe negative radial anisotropy in the upper crust that is associated mainly with the location of a previously reported mantle plume. The anisotropy could be attributed to the vertical alignment of fossil microcracks or metamorphic foliations due to the upwelling of plume material. A strong positive radial anisotropy is centered at the location of an inferred boundary between the Congo Craton and the Oubanguides Belt that might be related to the preferred orientation of crustal anisotropic minerals associated with shearing in this fault zone. The middle crust is characterized by a widespread negative radial anisotropy that is likely caused by the flow-induced alignment of anisotropic minerals that crystallized during magma intrusion. The magnitude of the radial anisotropy varies systematically from predominantly negative in the middle crust to positive in the lower crust. The imaged patterns of the isotropic velocity and radial anisotropy are consistent with previous studies and agree with regional tectonics.

  8. Radial Mixing in Turbomachines

    DTIC Science & Technology

    1991-03-31

    Belgium March 31, 1991 Final Scientific Report June 1, 1989 - July 31, 1990 VUB -STR -17 Approved for public release; distribution unlimited. - Prepared ...secondary flows and turbulence as sources of mixing was investigated by conducting experiments using hot-wire anemometry and ehtylene tracer gas

  9. An automated method for measurement of methoxetamine in human plasma by use of turbulent flow on-line extraction coupled with liquid chromatography and mass spectrometric detection.

    PubMed

    Abe, Emuri; Ricard, Florian; Darrouzain, François; Alvarez, Jean Claude

    2013-01-01

    Methoxetamine is a new ketamine derivative designer drug which has recently become available via the Internet marketed as "legal ketamine". It is a new dissociative recreational drug, acting as an NMDA receptor antagonist and dopamine reuptake inhibitor. The objective of this study was to develop on-line automated sample preparation using a TurboFlow device coupled with liquid chromatography with ion-trap mass spectrometric detection for measurement of methoxetamine in human plasma. Samples (100 μL) were vortex mixed with internal standard solution (ketamine-d4 in acetonitrile). After centrifugation, 20 μL of the supernatant was injected on to a 50 mm × 0.5-mm C18XL Turboflow column. The retained analytes were then back-flushed on to a 50 mm × 3-mm (3 μm) Hypersil Gold analytical column for chromatographic separation, then eluted with a formate buffer-acetonitrile gradient. Methoxetamine and the IS were ionized by electrospray in positive mode. Parent [M + H](+) ions were m/z 248.1 for methoxetamine and m/z 242.0 for the IS. The most intense product ions from methoxetamine (m/z 203.0) and the IS (m/z 224.0) were used for quantification. The assay was accurate (96.8-108.8% range) and precise (intra and inter-day coefficients of variation <8.8%) over the range of 2.0 (lower limit of quantification) to 1000.0 ng mL(-1) (upper limit of quantification). No matrix effect was observed. This method has been successfully applied to determination of plasma concentrations of methoxetamine in the first French hospitalization case report after acute intoxication; the plasma concentration was 136 ng mL(-1).

  10. An improved flow analysis-ion chromatography method for determination of cationic and anionic species at trace levels in Antarctic ice cores.

    PubMed

    Morganti, Andrea; Becagli, Silvia; Castellano, Emiliano; Severi, Mirko; Traversi, Rita; Udisti, Roberto

    2007-11-12

    A method was developed for the quantitative determination of cations and anions in Antarctic ice cores at microgL(-1) and sub-microgL(-1) levels by ion chromatography (IC), after ultra-clean decontamination procedures. Strict manipulation and decontamination procedures were used in sub-sampling, in order to minimise sample contamination. Na+, NH4+, K+, Mg2+ and Ca2+ were determined by 12-min isocratic elution (H2SO4 eluent). Contemporaneously, in a parallel device, F-, MSA (methanesulfonic acid), Cl-, NO3- and SO4(2-) were analysed in a single 12-min run with multiple-step elution using Na2CO3/NaHCO3 as eluent. Melted ice samples were pumped from their still-closed containers (polystyrene accuvettes with polyethylene caps), shared between the two ion chromatographic systems, online filtered (0.45 microm Teflon membrane) and pre-concentrated (anions and cations pre-concentration columns) using a flow analysis system, thus avoiding uptake of contaminants from the laboratory atmosphere. Sensitivity, linear range, reproducibility and detection limit were evaluated for each chemical species. Anion or cation detection limits ranged from 0.01 to 0.15 microgL(-1) by using a relatively small sample volume (1.5 mL). Such values are significantly lower than those reported in literature for almost all the components. These methods were successfully applied to the analysis of cations and anions at trace levels in the Dome C ice core. The composition of the atmospheric aerosol for the last 850 kyr was reconstructed by high-resolution continuous chemical stratigraphies. Concentration trends in the last nine glacial-interglacial climatic cycles were shown and briefly discussed.

  11. 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

  12. Radially sandwiched cylindrical piezoelectric transducer

    NASA Astrophysics Data System (ADS)

    Lin, Shuyu; Fu, Zhiqiang; Zhang, Xiaoli; Wang, Yong; Hu, Jing

    2013-01-01

    A new type of radially sandwiched piezoelectric short cylindrical transducer is developed and its radial vibration is studied. The transducer is composed of a solid metal disk, a radially polarized piezoelectric ceramic short tube and a metal tube. The radial vibrations of the solid metal disk, the radially polarized piezoelectric tube and the metal tube are analyzed and their electromechanical equivalent circuits are introduced. Based on the mechanical boundary conditions among the metal disk, the piezoelectric tube and the metal tube, a three-port electromechanical equivalent circuit for the radially sandwiched transducer is obtained and the frequency equation is given. The theoretical relationship of the resonance and anti-resonance frequencies and the effective electromechanical coupling coefficient with the geometrical dimensions is analyzed. The radial vibration of the sandwiched transducer is simulated by using two different numerical methods. It is shown that the analytical resonance and anti-resonance frequencies are in good agreement with the numerically simulated results. The transducer is expected to be used in piezoelectric resonators, actuators and ultrasonic radiators in ultrasonic and underwater sound applications.

  13. Comparison of perfusion media and monoliths for protein and virus-like particle chromatography.

    PubMed

    Wu, Yige; Abraham, Dicky; Carta, Giorgio

    2016-05-20

    Structural and performance characteristics of perfusion chromatography media (POROS HS 20 and 50) and those of a polymethacrylate monolith (CIM SO3-1 tube monolith column) are compared for protein and virus-like particle chromatography using 1mL columns. Axial flow columns are used for POROS while the monolith has a radial flow configuration, which provides comparable operating pressures. The POROS beads contain a bimodal distribution of pore sizes, some as large as 0.5μm, which allow a small fraction of the mobile phase to flow within the particles, while the monolith contains 1-2μm flow channels. For proteins (lysozyme and IgG), the dynamic binding capacity of the POROS columns is more than twice that of the monolith at longer residence times. While the DBC of the POROS HS 50 column decreases at shorter residence times, the DBC of the POROS HS 20 column for IgG remains nearly twice that of the monolith at residence times at least as low as 0.2min as a result of intraparticle convection. Protein recoveries are comparable for all three columns. For VLPs, however, the eluted peaks are broader and recovery is lower for the monolith than for the POROS columns and is dependent on the direction of flow in the monolith, which is attributed to denser layer observed by SEM at the inlet surface of the monolith that appears to trap VLPs when loading in the normal flow direction.

  14. Submarine radial vents on Mauna Loa Volcano, Hawai'i

    USGS Publications Warehouse

    Wanless, V. Dorsey; Garcia, M.O.; Trusdell, F.A.; Rhodes, J.M.; Norman, M.D.; Weis, Dominique; Fornari, D.J.; Kurz, M.D.; Guillou, Herve

    2006-01-01

    A 2002 multibeam sonar survey of Mauna Loa's western flank revealed ten submarine radial vents and three submarine lava flows. Only one submarine radial vent was known previously. The ages of these vents are constrained by eyewitness accounts, geologic relationships, Mn-Fe coatings, and geochemical stratigraphy; they range from 128 years B.P. to possibly 47 ka. Eight of the radial vents produced degassed lavas despite eruption in water depths sufficient to inhibit sulfur degassing. These vents formed truncated cones and short lava flows. Two vents produced undegassed lavas that created “irregular” cones and longer lava flows. Compositionally and isotopically, the submarine radial vent lavas are typical of Mauna Loa lavas, except two cones that erupted alkalic lavas. He-Sr isotopes for the radial vent lavas follow Mauna Loa's evolutionary trend. The compositional and isotopic heterogeneity of these lavas indicates most had distinct parental magmas. Bathymetry and acoustic backscatter results, along with photography and sampling during four JASON2 dives, are used to produce a detailed geologic map to evaluate Mauna Loa's submarine geologic history. The new map shows that the 1877 submarine eruption was much larger than previously thought, resulting in a 10% increase for recent volcanism. Furthermore, although alkalic lavas were found at two radial vents, there is no systematic increase in alkalinity among these or other Mauna Loa lavas as expected for a dying volcano. These results refute an interpretation that Mauna Loa's volcanism is waning. The submarine radial vents and flows cover 29 km2 of seafloor and comprise a total volume of ∼2×109 m3 of lava, reinforcing the idea that submarine lava eruptions are important in the growth of oceanic island volcanoes even after they emerged above sea level.

  15. 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)

  16. Radial pump impeller measurements using a laser Doppler velocimeter

    NASA Astrophysics Data System (ADS)

    Kannemans, H.

    1980-03-01

    A shrouded fully transparent radial pump impeller with thin backswept blades has been tested using a laser Doppler velocimeter. Two components of the velocity were measured relative to the laboratory reference frame in a plane perpendicular to the axis of rotation. The velocity distribution is presented relative to the blades at different radii and different flow rates over the whole blade passage. The results show that the flow is essentially unsteady and, at low flow rate, highly influenced by viscous effects. A comparison between the experimental data and a potential flow theory shows good agreement at high flow rates.

  17. 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.

  18. High-performance liquid chromatography of the renal blood flow marker p-aminohippuric acid (PAH) and its metabolite N-acetyl PAH improves PAH clearance measurements.

    PubMed

    Decosterd, L A; Karagiannis, A; Roulet, J M; Bélaz, N; Appenzeller, M; Buclin, T; Vogel, P; Biollaz, J

    1997-12-05

    PAH (N-(4-aminobenzoyl)glycin) clearance measurements have been used for 50 years in clinical research for the determination of renal plasma flow. The quantitation of PAH in plasma or urine is generally performed by colorimetric method after diazotation reaction but the measurements must be corrected for the unspecific residual response observed in blank plasma. We have developed a HPLC method to specifically determine PAH and its metabolite NAc-PAH using a gradient elution ion-pair reversed-phase chromatography with UV detection at 273 and 265 nm, respectively. The separations were performed at room temperature on a ChromCart (125 mmx4 mm I.D.) Nucleosil 100-5 microm C18AB cartridge column, using a gradient elution of MeOH-buffer pH 3.9 1:99-->15:85 over 15 min. The pH 3.9 buffered aqueous solution consisted in a mixture of 375 ml sodium citrate-citric acid solution (21.01 g citric acid and 8.0 g NaOH per liter), added up with 2.7 ml H3PO4 85%, 1.0 g of sodium heptanesulfonate and completed ad 1000 ml with ultrapure water. The N-acetyltransferase activity does not seem to notably affect PAH clearances, although NAc-PAH represents 10.2+/-2.7% of PAH excreted unchanged in 12 healthy subjects. The performance of the HPLC and the colorimetric method have been compared using urine and plasma samples collected from healthy volunteers. Good correlations (r=0.94 and 0.97, for plasma and urine, respectively) are found between the results obtained with both techniques. However, the colorimetric method gives higher concentrations of PAH in urine and lower concentrations in plasma than those determined by HPLC. Hence, both renal (ClR) and systemic (Cls) clearances are systematically higher (35.1 and 17.8%, respectively) with the colorimetric method. The fraction of PAH excreted by the kidney ClR/ClS calculated from HPLC data (n=143) is, as expected, always <1 (mean=0.73+/-0.11), whereas the colorimetric method gives a mean extraction ratio of 0.87+/-0.13 implying some

  19. On-line UV-photooxidation with peroxodisulfate for automated flow injection and for high-performance liquid chromatography coupled to hydride generation atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Tsalev, Dimiter L.; Sperling, Michael; Welz, Bernhard

    2000-04-01

    An automated on-line UV photooxidation with peroxodisulfate of some environmentally relevant organoarsenic and organotin compounds in a system built from commercially available modules has been studied and optimised with a view to both species-independent quantification of the total arsenic or tin in samples containing different organic species by flow injection hydride generation atomic absorption spectrometry (FI-HGAAS) and speciation analysis by coupled high-performance liquid chromatography (HPLC) with HGAAS detection. For organoarsenicals, the reaction with alkaline peroxodisulfate in a 10-15-m knotted reactor for >1.5 min insures >90% transformation of inorganic As(III) and six organoarsenic species to arsenate: monomethylarsonate, dimethylarsinate, arsenobetaine, arsenocholine, trimethylarsine oxide and tetramethylarsonium. For organotins, the UV photooxidation with acidic peroxodisulfate at 95-100°C provides recoveries of >80% for the inorganic tin, dimethyltin, trimethyltin, triethyltin, tripropyltin, triphenyltin, monobutyltin, dibutyltin and tributyltin but only approximately 15% for tetrabutyltin. The best characteristic masses in integrated absorbance ( Aint) and peak-height ( Ap) measurements, respectively, are 30 pg and 480 pg for arsenic(V) and 22 pg and 410 pg for tin(IV), employing 100-μl injections. The RSDs are 5.5% and 8.5% at 5 ng As(V) levels and 4.3% and 6.4% at 10 ng Sn(IV) levels in Aint and Ap modes, respectively. The limits of detection (LOD, 3σ) for As are 7 μg l -1 and 4 μg l -1 in FI-UV-HGAAS and HPLC-UV-HGAAS, respectively. The LODs for i-Sn(IV) are 2 μg l -1 in FI-UV-HGAAS, with both Aint and Ap measurements. The sample throughput rates are 20 and 12 samples per hour with 10-m and 15-m knotted reactors (i.d. 0.5 mm), respectively. Urine certified reference materials containing 0.052-0.48 μg ml -1 As have been analysed for their total arsenic content.

  20. Bisphenol A determination in baby bottles by chemiluminescence enzyme-linked immunosorbent assay, lateral flow immunoassay and liquid chromatography tandem mass spectrometry.

    PubMed

    Maiolini, Elisabetta; Ferri, Elida; Pitasi, Agata Laura; Montoya, Angel; Di Giovanni, Manuela; Errani, Ermanno; Girotti, Stefano

    2014-01-07

    Two immunoassays, a Lateral Flow ImmunoAssay (LFIA) based on colloidal gold nanoparticle labels and an indirect competitive chemiluminescence enzyme-linked immunosorbent assay (CL-ELISA), were developed and a high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was optimized to assess the possible release of bisphenol A (BPA, 4,4'-isopropylidenediphenol) from different plastic baby bottles treated with simulating solutions. Coating conjugate concentration, anti-BPA antibody dilution, incubation time of the primary and secondary antibodies, and tolerance to different organic solvents were optimized to obtain the best performance of the ELISA with chemiluminescent end-point detection. The influence of different buffers on LFIA performance was also evaluated. Both methods showed good repeatability (mean CV value around 13%) and sensitivity. Reproducibility tests for CL-ELISA gave a mean CV value of about 25%. The IC50 and Limit of Detection (LOD) values of CL-ELISA were 0.2 and 0.02 ng mL(-1), respectively. The LOD of LFIA was 0.1 μg mL(-1). A LC-MS/MS method was also optimized. The separation was performed in a C18 column with a triple-quadrupole mass spectrometer with electrospray ionisation interface. The method showed a good linearity in the range 2 to 500 ng mL(-1), with a regression coefficient of 0.998. In the simulating solutions the detection and quantification limits, calculated by the signal to noise level of 3 (S/N = 3), were 5.8 ng mL(-1) and 17.4 ng mL(-1), respectively. This limit of quantification was about 3 and 35 times lower than the permitted limits set by the official method CEN/TS 13130-13 (0.05 μg mL(-1)) and by the Directive 2004/19/EC (0.6 μg mL(-1)), respectively. The methods were applied to determine BPA release from baby bottles, performing repeated procedures according to EU and national regulations. The results demonstrated that no BPA migration from the tested plastic materials occurred with only one

  1. 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

    2015-10-02

    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 85μm 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.

  2. Extensive database of liquid phase diffusion coefficients of some frequently used test molecules in reversed-phase liquid chromatography and hydrophilic interaction liquid chromatography.

    PubMed

    Song, Huiying; Vanderheyden, Yoachim; Adams, Erwin; Desmet, Gert; Cabooter, Deirdre

    2016-07-15

    Diffusion plays an important role in all aspects of band broadening in chromatography. An accurate knowledge of molecular diffusion coefficients in different mobile phases is therefore crucial in fundamental column performance studies. Correlations available in literature, such as the Wilke-Chang equation, can provide good approximations of molecular diffusion under reversed-phase conditions. However, these correlations have been demonstrated to be less accurate for mobile phases containing a large percentage of acetonitrile, as is the case in hydrophilic interaction liquid chromatography. A database of experimentally measured molecular diffusion coefficients of some 45 polar and apolar compounds that are frequently used as test molecules under hydrophilic interaction liquid chromatography and reversed-phase conditions is therefore presented. Special attention is given to diffusion coefficients of polar compounds obtained in large percentages of acetonitrile (>90%). The effect of the buffer concentration (5-10mM ammonium acetate) on the obtained diffusion coefficients is investigated and is demonstrated to mainly influence the molecular diffusion of charged molecules. Diffusion coefficients are measured using the Taylor-Aris method and hence deduced from the peak broadening of a solute when flowing through a long open tube. The validity of the set-up employed for the measurement of the diffusion coefficients is demonstrated by ruling out the occurrence of longitudinal diffusion, secondary flow interactions and extra-column effects, while it is also shown that radial equilibration in the 15m long capillary is effective.

  3. Determining estrogenic steroids in Taipei waters and removal in drinking water treatment using high-flow solid-phase extraction and liquid chromatography/tandem mass spectrometry.

    PubMed

    Chen, Chia-Yang; Wen, Tzu-Yao; Wang, Gen-Shuh; Cheng, Hui-Wen; Lin, Ying-Hsuan; Lien, Guang-Wen

    2007-06-01

    River water and wastewater treatment plant (WWTP) effluents from metropolitan Taipei, Taiwan were tested for the presence of the pollutants estrone (E1), estriol (E3), 17beta-estradiol (E2), and 17alpha-ethinylestradiol (EE2) using a new methodology that involves high-flow solid-phase extraction and liquid chromatography/tandem mass spectrometry. The method was also used to investigate the removal of the analytes by conventional drinking water treatment processes. Without adjusting the pH, we extracted 1-L samples with PolarPlus C18 Speedisks under a flow rate exceeding 100 mL/min, in which six samples could be done simultaneously using an extraction station. The adsorbent was washed with 40% methanol/60% water and then eluted by 50% methanol/50% dichloromethane. The eluate was concentrated until almost dry and was reconstituted by 20 microL of methanol. Quantitation was done by LC-MS/MS-negative electrospray ionization in the selected reaction monitoring mode with isotope-dilution techniques. The mobile phase was 10 mM N-methylmorpholine aqueous solution/acetonitrile with gradient elution. Mean recoveries of spiked Milli-Q water were 65-79% and precisions were within 2-20% of the tested concentrations (5.0-200 ng/L). The method was validated with spiked upstream river water; precisions were most within 10% of the tested concentrations (10-100 ng/L) with most RSDs<10%. LODs of the environmental matrixes were 0.78-7.65 ng/L. A pre-filtration step before solid-phase extraction may significantly influence the measurement of E1 and EE2 concentrations; disk overloading by water matrix may also impact analyte recoveries along with ion suppression. In the Taipei water study, the four steroid estrogens were detected in river samples (ca. 15 ng/L for E2 and EE2 and 35-45 ng/L for E1 and E3). Average levels of 19-26 ng/L for E1, E2, and EE2 were detected in most wastewater effluents, while only a single effluent sample contained E3. The higher level in the river was likely

  4. Multielement characterization of metal-humic substances complexation by size exclusion chromatography, asymmetrical flow field-flow fractionation, ultrafiltration and inductively coupled plasma-mass spectrometry detection: a comparative approach.

    PubMed

    Bolea, E; Gorriz, M P; Bouby, M; Laborda, F; Castillo, J R; Geckeis, H

    2006-10-06

    The use of three different separation techniques, ultrafiltration (UF), high performance size exclusion chromatography (HPSEC) and asymmetrical flow field-flow fractionation (AsFlFFF), for the characterization of a compost leachate is described. The possible interaction of about 30 elements with different size fractions of humic substances (HS) has been investigated coupling these separation techniques with UV-vis absorption spectrophotometry and inductively coupled plasma-mass spectrometry (ICP-MS) as detection techniques. The organic matter is constituted by a polydisperse mixture of humic substances ranging from low molecular weights (around 1kDa) to significantly larger entities. Elements can be classified into three main groups with regard to their interaction with HS. The first group is constituted by primarily the monovalent alkaline metal ions and anionic species like B, W, Mo, As existing as oxyanions all being not significantly associated to HS. The second group consists of elements that are at least partly associated to a smaller HS size fraction (such as Ni, Cu, Cr and Co). A third group of mainly tri- and tetravalent metal ions like Al, Fe, the lanthanides, Sn and Th are rather associated to larger-sized HS fractions. The three separation techniques provide a fairly consistent size classification for most of the metal ions, even though slight disagreements were observed. The number-average molecular weight (Mn), the weight-average molecular weight (Mw) and the polydispersity (rho) parameters have been calculated both from AsFlFFF and HPSEC experiments and compared for HS and some metal-HS species. Differences in values can be partly explained by an overloading effect observed in the AsFlFFF experiments induced by electrostatic repulsion effects in the low ionic strength, high pH carrier solution. Size information obtained from ultrafiltration is not as resolved as for the other methods. Molecular weight cut-offs (MWCO) of the individual filter

  5. The Radially Symmetric Euler Equations as an Exterior Differential System

    NASA Astrophysics Data System (ADS)

    Baty, Roy; Ramsey, Scott; Schmidt, Joseph

    2016-11-01

    This work develops the Euler equations as an exterior differential system in radially symmetric coordinates. The Euler equations are studied for unsteady, compressible, inviscid fluids in one-dimensional, converging flow fields with a general equation of state. The basic geometrical constructions (for example, the differential forms, tangent planes, jet space, and differential ideal) used to define and analyze differential equations as systems of exterior forms are reviewed and discussed for converging flows. Application of the Frobenius theorem to the question of the existence of solutions to radially symmetric converging flows is also reviewed and discussed. The exterior differential system is further applied to derive and analyze the general family of characteristic vector fields associated with the one-dimensional inviscid flow equations.

  6. 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 aqueous–aqueous 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

  7. 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.

  8. Green chromatography.

    PubMed

    Płotka, Justyna; Tobiszewski, Marek; Sulej, Anna Maria; Kupska, Magdalena; Górecki, Tadeusz; Namieśnik, Jacek

    2013-09-13

    Analysis of organic compounds in samples characterized by different composition of the matrix is very important in many areas. A vast majority of organic compound determinations are performed using gas or liquid chromatographic methods. It is thus very important that these methods have negligible environmental impact. Chromatographic techniques have the potential to be greener at all steps of the analysis, from sample collection and preparation to separation and final determination. The paper summarizes the approaches used to accomplish the goals of green chromatography. While complete elimination of sample preparation would be an ideal approach, it is not always practical. Solventless extraction techniques offer a very good alternative. Where solvents must be used, the focus should be on the minimization of their consumption. The approaches used to make chromatographic separations greener differ depending on the type of chromatography. In gas chromatography it is advisable to move away from using helium as the carrier gas because it is a non-renewable resource. GC separations using low thermal mass technology can be greener because of energy savings offered by this technology. In liquid chromatography the focus should be on the reduction of solvent consumption and replacement of toxic and environmentally hazardous solvents with more benign alternatives. Multidimensional separation techniques have the potential to make the analysis greener in both GC and LC. The environmental impact of the method is often determined by the location of the instrument with respect to the sample collection point.

  9. Ion Chromatography.

    ERIC Educational Resources Information Center

    Mulik, James D.; Sawicki, Eugene

    1979-01-01

    Accurate for the analysis of ions in solution, this form of analysis enables the analyst to directly assay many compounds that previously were difficult or impossible to analyze. The method is a combination of the methodologies of ion exchange, liquid chromatography, and conductimetric determination with eluant suppression. (Author/RE)

  10. 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.

  11. 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.

  12. Cooled High-Temperature Radial Turbine Program. Phase 2

    DTIC Science & Technology

    1992-05-01

    proposed for advanced engines with high power-to-weight and inproved SFC requirements. The addition of cooling to the blades of a metal radial turbine ...4 secl/2 ) 62.2 Blade - jet Speed Ratio 0.66 Adiabatic Efficiency (T-to-T, %) 87.0 Cooling flows for the gasifier turbine section are set at 5.7%. The...Way Cincinnati, OH 45215-6301 85 COOLED HIGH-TEMPERATURE RADIAL TURBINE PROGRAM DISTRIBUTION LIST Number Qf Copies General Electric Aircraft Engines

  13. Vortex Whistle in Radial Intake

    DTIC Science & Technology

    2004-10-01

    RTO-MP-AVT-110 22 - 1 Vortex Whistle in Radial Intake Dr. Man-Chun Tse Pratt & Whitney Canada Corp. 1000 Marie-Victorin, Longueuil , Quebec...ORGANIZATION NAME(S) AND ADDRESS(ES) Pratt & Whitney Canada Corp. 1000 Marie-Victorin, Longueuil , Quebec, Canada, J4G 1A1 8. PERFORMING ORGANIZATION REPORT

  14. Asymptotic screened hydrogenic radial integrals

    NASA Technical Reports Server (NTRS)

    Olsgaard, D. A.; Khan, F.; Khandelwal, G. S.

    1988-01-01

    The usefulness of the screened hydrogenic model for the transitions of the helium sequence is studied. The screened hydrogenic radial dipole integral for discrete-discrete transitions from the initial state to the final state is asymptotically expanded to the lowest order such that the final quantum number n approaches infinity. The analytical expression obtained is in terms of confluent hypergeometric functions.

  15. 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-μL 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.

  16. Radial reactor for trichloroethylene steam reforming

    SciTech Connect

    Moates, F.C.; McMinn, T.E.; Richardson, J.T.

    1999-11-01

    A ceramic foam radial reactor was used to convert trichloroethylene by steam reforming, using 0.5 wt. % Pt as a catalyst. With a quartz enclosure heated externally by infrared lamps, the inlet temperature to the catalyst bed was low enough to suppress pyrolysis, but high conversions (0.99999 +) were achieved at the exit. Stable operation up to 600 h with a space velocity of 5.6 x 10{sup 4}h{sup {minus}1} was achieved, but reactant break-through then occurred, and the catalyst quickly deactivated. Although the deactivated catalyst was regenerated with carbon burning, activity decline was more rapid due to platinum sintering and washcoat degradation. Measured temperature profiles and model calculations indicated a large gradient in the bed and suggested that stable operation could be extended at lower space velocities. Axial temperature profiles were not uniform, since preferential flow occurred in the middle and lower regions of the radial bed. Potential improvements for future designs are suggested.

  17. The effect of radial pressure force on rotating double tearing mode in compressible plasmas

    NASA Astrophysics Data System (ADS)

    Wang, Xian-Qu; Xiong, Guo-Zhen; Li, Xiao-Qing

    2016-05-01

    The role of radial pressure force in the interlocking dynamics of double tearing modes (DTMs) is investigated by force balance analysis based on the compressible magnetohydrodynamics (MHD) model. It is found that the stability of symmetric DTMs is dominated by the radial pressure force rather than the field line bending force. Owing to the compressibility of rotating plasmas, unbalanced radial forces can just result in the rotating islands drift toward each other in the radial direction but do not trigger the explosive growth of the mode in the interlocking process, which is different from that of antisymmetric DTM without flow.

  18. Gas chromatography.

    PubMed

    Eiceman, G A; Hill, H H; Gardea-Torresdey, J

    1998-06-15

    This review of the fundamental developments in gas chromatography (GC) includes articles published from 1996 and 1997 and an occasional citation prior to 1996. The literature was reviewed principally using CA Selects for Gas Chromatography from Chemical Abstracts Service, and some significant articles from late 1997 may be missing from the review. In addition, the online SciSearch Database (Institute for Scientific Information) capability was used to abstract review articles or books. As with the prior recent reviews, emphasis has been given to the identification and discussion of selected developments, rather than a presentation of a comprehensive literature search, now available widely through computer-based resources. During the last two years, several themes emerged from a review of the literature. Multidimensional gas chromatography has undergone transformation encompassing a broad range of activity, including attempts to establish methods using chromatographic principles rather than a totally empirical approach. Another trend noted was a comparatively large effort in chromatographic theory through modeling efforts; these presumably became resurgent with inexpensive and powerful computing tools. Finally, an impressive level of activity was noted through the themes highlighted in this review, and this was particularly true with detectors and field instruments.

  19. Investigation of inner and outer phase formation in tube radial distribution phenomenon using various types of mixed solvent solutions.

    PubMed

    Fujinaga, Satoshi; Unesaki, Katsuya; Kawai, Yuki; Kitaguchi, Koichi; Nagatani, Kosuke; Hashimoto, Masahiko; Tsukagoshi, Kazuhiko; Mizushima, Jiro

    2014-01-01

    When mixed solvent solutions, such as ternary water-hydrophilic/hydrophobic organic solvents, water-surfactant, water-ionic liquid, and fluorous-organic solvents are delivered into a microspace under laminar flow conditions, the solvent molecules are radially distributed in the microspace, generating inner and outer phases. This specific fluidic behavior is termed "tube radial distribution phenomenon" (TRDP). In this study, the factors influencing the formation of inner and outer phases in the TRDP using the above-mentioned mixed solvent solutions were investigated. We examined phase diagrams, viscosities of the two phases (upper and lower phases in a batch vessel), volume ratios of the phases, and bright-light or fluorescence photographs of the TRDP. When the difference in viscosities between the two phases was large (> approximately 0.73 mPa·s), the phase with the larger viscosity formed an inner phase regardless of the volume ratios, whereas when the difference was small (< approximately 0.42 mPa·s), the phase with the larger volume formed an inner phase. The TRDP using a water-surfactant mixed solution was also investigated in capillary chromatography based on TRDP.

  20. /Chromatography+RECOVERY=superresolution chromatography

    NASA Astrophysics Data System (ADS)

    Kosarev, E. L.; Muranov, K. O.

    2003-04-01

    A method for improving the resolution of the chromatographic analysis based on deriving the point-spread function of a chromatographic column, i.e., a chromatogram of an individual compound, is described. The system of two data sets, namely, a chromatogram of a substance analyzed and a point-spread function of a chromatographic column in combination with the noise statistics, makes it possible to use the RECOVERY signal-reconstruction software package described in paper by Gelfgat et al. (Comp. Phys. Commun. 74 (1993) 335). The proposed method has been tested by chromatography of bovine serum albumin using gel filtration. The resultant resolution exceeds that reached using high-performance liquid chromatography (with the cost of the instruments being lower by a factor of 15-20).

  1. Principles of Liquid Chromatography

    NASA Astrophysics Data System (ADS)

    Bakalyar, Stephen R.

    This article reviews the basic principles of high performance liquid chromatography (HPLC). The introductory section provides an overview of the HPLC technique, placing it in historical context and discussing the elementary facts of the separation mechanism. The next section discusses the nature of resolution, describing the two principal aspects, zone center separation and zone spreading. The third section takes a detailed look at how HPLC is used in practice to achieve a separation. It discusses the three key variables that need to be adjusted: retention, efficiency, and selectivity. A fourth section is concerned with various relationships of practical importance: flow rate, temperature, and pressure. A final section discusses future trends in HPLC.

  2. 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.

  3. Velocidades radiales en Collinder 121

    NASA Astrophysics Data System (ADS)

    Arnal, M.; Morrell, N.

    Se han llevado a cabo observaciones espectroscópicas de unas treinta estrellas que son posibles miembros del cúmulo abierto Collinder 121. Las mismas fueron realizadas con el telescopio de 2.15m del Complejo Astronómico El Leoncito (CASLEO). El análisis de las velocidades radiales derivadas del material obtenido, confirma la realidad de Collinder 121, al menos desde el punto de vista cinemático. La velocidad radial baricentral (LSR) del cúmulo es de +17 ± 3 km.s-1. Esta velocidad coincide, dentro de los errores, con la velocidad radial (LSR) de la nebulosa anillo S308, la cual es de ~20 ± 10 km.s-1. Como S308 se encuentra físicamente asociada a la estrella Wolf-Rayet HD~50896, es muy probable que esta última sea un miembro de Collinder 121. Desde un punto de vista cinemático, la supergigante roja HD~50877 (K3Iab) también pertenecería a Collinder 121. Basándonos en la pertenencia de HD~50896 a Collinder 121, y en la interacción encontrada entre el viento de esta estrella y el medio interestelar circundante a la misma, se estima para este cúmulo una distancia del orden de 1 kpc.

  4. Dielectrokinetic chromatography and devices thereof

    SciTech Connect

    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.

  5. 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

  6. Radial Transport and Meridional Circulation in Accretion Disks

    NASA Astrophysics Data System (ADS)

    Philippov, Alexander A.; Rafikov, Roman R.

    2017-03-01

    Radial transport of particles, elements and fluid driven by internal stresses in three-dimensional (3D) astrophysical accretion disks is an important phenomenon, potentially relevant for the outward dust transport in protoplanetary disks, origin of the refractory particles in comets, isotopic equilibration in the Earth–Moon system, etc. To gain better insight into these processes, we explore the dependence of meridional circulation in 3D disks with shear viscosity on their thermal stratification, and demonstrate a strong effect of the latter on the radial flow. Previous locally isothermal studies have normally found a pattern of the radial outflow near the midplane, switching to inflow higher up. Here we show, both analytically and numerically, that a flow that is inward at all altitudes is possible in disks with entropy and temperature steeply increasing with height. Such thermodynamic conditions may be typical in the optically thin, viscously heated accretion disks. Disks in which these conditions do not hold should feature radial outflow near the midplane, as long as their internal stress is provided by the shear viscosity. Our results can also be used for designing hydrodynamical disk simulations with a prescribed pattern of the meridional circulation.

  7. 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.

  8. 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.

  9. 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...

  10. 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.

  11. 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

  12. Radial tears of the menisci: MR findings.

    PubMed

    Tuckman, G A; Miller, W J; Remo, J W; Fritts, H M; Rozansky, M I

    1994-08-01

    Radial meniscal tears have a plane of cleavage oriented across the short axis of the meniscus in the same plane in which radial images are oriented. These tears are important to recognize, because they have clinical implications different from those of other meniscal tears with respect to meniscal function, orthopedic treatment, and clinical course. Depending on their size, location, and orientation, radial tears can have different appearances on standard MR images. Certain types can be fairly subtle to diagnose. The purpose of this essay is to illustrate the varied appearances of radial tears on MR images and the findings commonly associated with radial tears.

  13. Radial vibrations of BPS skyrmions

    NASA Astrophysics Data System (ADS)

    Adam, C.; Haberichter, M.; Romanczukiewicz, T.; Wereszczynski, A.

    2016-11-01

    We study radial vibrations of spherically symmetric Skyrmions in the Bogomol'nyi-Prasad-Sommerfield Skyrme model. Concretely, we numerically solve the linearized field equations for small fluctuations in a Skyrmion background, both for linearly stable oscillations and for (unstable) resonances. This is complemented by numerical solutions of the full nonlinear system, which confirm all the results of the linear analysis. In all cases, the resulting fundamental excitation provides a rather accurate value for the Roper resonance, supporting the hypothesis that the Bogomol'nyi-Prasad-Sommerfield Skyrme model already gives a reasonable approximate description of this resonance. Furthermore, for many potentials additional higher resonances appear, again in agreement with known experimental results.

  14. 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.

  15. 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

    2014-10-03

    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.

  16. 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.

  17. Socket stars: UBVRJIK radial profiles

    NASA Astrophysics Data System (ADS)

    Schaefer, Bradley E.

    1995-05-01

    Visual inspectin of stars embedded in H II nebulae has shown a significant fraction to be surrounded by nearly symmetric extended regions within which the nebular brightness is apparently significantly fainter than is typical for the surrounding area. These 'socket stars' might be caused by a bubble in the nebula blown out by a stellar wind or they might be caused by a circumstellar envelope of dust hiding the emission behind the star. As such, the sockets could be the first manifestation of a previously unknown component of pre-main-sequence stars. Unfortunately, no quantitative proof of the existence of sockets has been presented. To fill this need, I have imaged 10 socket stars and six background stars with CCD cameras and infrared array cameras. From these images, I have constructed radial plots which should reveal dips in brightness immediately outside the seeing disk. The radial plots do not show any evidence for the existence of sockets. A detailed examination of the photographs orginally used to identify the sockets show that the causes of these reports are (1) artifacts resulting from the photographic process of dodging and (2) random coincidence of stars with local minima in nebular brightness. Thus, I conclude that 'socket stars' do not exist.

  18. 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.

  19. Radial blanket assembly orificing arrangement

    DOEpatents

    Patterson, J.F.

    1975-07-01

    A nuclear reactor core for a liquid metal cooled fast breeder reactor is described in which means are provided for increasing the coolant flow through the reactor fuel assemblies as the reactor ages by varying the coolant flow rate with the changing coolant requirements during the core operating lifetime. (auth)

  20. 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.

  1. 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)

  2. 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.

  3. Use of on-line stop-flow heart-cutting two-dimensional high performance liquid chromatography for simultaneous determination of 12 major constituents in tartary buckwheat (Fagopyrum tataricum Gaertn).

    PubMed

    Ren, Qiang; Wu, Caisheng; Zhang, Jinlan

    2013-08-23

    The use of two-dimensional liquid chromatography (2D-LC) for quantification studies presents challenges with respect to repeatability, precision, and robustness. The present study used an on-line stop-flow heart-cutting 2D-LC system to determine 12 chemical constituents in tartary buckwheat. A combination of various stationary phases was developed and bridged using two switch valves as the interface. Hydrophilic interaction chromatography was chosen for separation in the first dimension ((1)D), and mixed mode stationary phases (an amide polar-embedded phase and alkyl-phenyl phase) were used in parallel for separation in the second dimension ((2)D). The mobile phase comprised acetonitrile and water containing 0.03% aqueous phosphoric acid. The sample was separated into two fractions on the (1)D column (HILIC-10 column) using 5% acetonitrile. One fraction, mainly comprising flavonoids, was directly eluted onto the head of (2)D column (Polar Advantage II column) and further separated using a linear gradient of 11-23% acetonitrile. The second fraction, containing phenylpropanoid glycosides, was trapped on the (1)D column. This retained fraction was back-flushed onto the (2)D column (Phenyl-1 column) and separated using a linear gradient of 35-43% acetonitrile. An on-line stop-flow heart-cutting 2D-LC system was successfully developed with column switching and back-flush. This 2D-LC system was validated and was able to simultaneously determine 12 major components in tartary buckwheat: seven flavonoids, four phenylpropanoid glycosides, and N-trans-feruloyltyramine. The system showed good performance with respect to linearity (r>0.996), repeatability (RSD, relative standard deviation<3.4%), intra-day and inter-day precision (RSD<4.6%), recovery (91.2-108%), limit of detection (LOD) (0.05-0.21μg/mL), and limit of quantification (LOQ) (0.10-0.41μg/mL). The on-line stop-flow heart-cutting 2D-LC system offers a potential approach to analyze compounds, which have similar

  4. Comprehensive two-dimensional gas chromatography under high outlet pressure conditions: a new approach to correct the flow-mismatch issue in the two dimensions.

    PubMed

    Peroni, Daniela; Janssen, Hans-Gerd

    2014-03-07

    The typical column sets employed in comprehensive two-dimensional gas chromatography (GC × GC) suffer from the impossibility to fully exploit the efficiency of both dimensions simultaneously. Adding a restrictor at the end of the second dimension is a possible approach to adjust the linear velocity profile. Under these high outlet pressure conditions the second dimension becomes much slower while the effect on the primary column is limited. The gap in terms of optimum inlet pressures is thus reduced. A program written in Microsoft Excel was used to calculate the efficiencies of the two dimensions in GC × GC at different outlet pressures. A GC × GC set-up with a restrictor at the end of the second dimension column was successfully installed. Experiments proved that this is a possible way to have a better exploitation of the columns. The chromatograms obtained for a number of applications confirm that the separations achieved at elevated outlet pressure are more efficient than those obtained with the same column set under atmospheric outlet conditions. The price to pay is that the separations become considerably slower.

  5. Tolerancing a radial velocity spectrometer within Zemax

    NASA Astrophysics Data System (ADS)

    Gibson, Steven R.

    2016-08-01

    Techniques are described for tolerancing a radial velocity spectrometer system within Zemax, including: how to set up and verify the tolerancing model, performance metrics and tolerance operands used, as well as post- Zemax analysis methods. Use of the tolerancing model for various analyses will be discussed, such as: alignment sensitivity, radial velocity sensitivity, and sensitivity of the optical system to temperature changes. Tolerance results from the Keck Planet Finder project (a precision radial velocity spectrometer of asymmetric white pupil design) will be shown.

  6. Thermal convection in a cylindrical annulus under a combined effect of the radial and vertical gravity

    NASA Astrophysics Data System (ADS)

    Meyer, Antoine; Jongmanns, Marcel; Meier, Martin; Egbers, Christoph; Mutabazi, Innocent

    2017-01-01

    The stability of the flow of a dielectric fluid confined in a cylindrical annulus submitted to a radial temperature gradient and a radial electric field is investigated theoretically and experimentally. The radial temperature gradient induces a vertical Archimedean buoyancy and a radial dielectrophoretic buoyancy. These two forces intervene simultaneously in the destabilization of the flow, leading to the occurrence of four types of modes depending on the relative intensity of these two buoyancies and on the fluid's properties: hydrodynamic and thermal modes that are axisymmetric and oscillatory, stationary columnar modes and electric modes which are stationary and non-axisymmetric modes. Experiments performed in a parabolic flight show the existence of non-axisymmetric modes that should be either columnar or helicoidal vortices.

  7. Relaminarization of fluid flows

    NASA Technical Reports Server (NTRS)

    Narasimha, R.; Sreenivasan, K. R.

    1979-01-01

    The mechanisms of the relaminarization of turbulent flows are investigated with a view to establishing any general principles that might govern them. Three basic archetypes of reverting flows are considered: the dissipative type, the absorptive type, and the Richardson type exemplified by a turbulent boundary layer subjected to severe acceleration. A number of other different reverting flows are then considered in the light of the analysis of these archetypes, including radial Poiseuille flow, convex boundary layers, flows reverting by rotation, injection, and suction, as well as heated horizontal and vertical gas flows. Magnetohydrodynamic duct flows are also examined. Applications of flow reversion for turbulence control are discussed.

  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.

  9. 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.

  10. 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.

  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.

  12. Hydrodesulfurization of Qaiyarah 80-205 sup 0 C naphtha fraction of alumina supported Co-Mo-oxides; Part 2: Using stopped flow gas chromatography

    SciTech Connect

    Ali, L.H.; Sulaiman, S.T.; AlTamer, M.Y. )

    1990-04-01

    The authors report the effective desulfurization of Qaiyarah 80-205{sup 0}C, naphtha fraction on alumina supported Co-Mo oxides, assembled in a GC column using H{sub 2} as a carrier gas and the stopped-flow technique. Over 90% of sulfur was removed from this partially cracked naphtha and a similar result (Ca 90%) was obtained when hydrodesulfurizing an acid-base treated naphtha. /sup 1/H nmr studies on the chromatographically separated hydrodesulfurized fractions revealed interesting structural parameters which leads to suggestions related to the occurrence of a reforming reaction and the liberation of fresh H{sub 2} gases which further promotes hydrodesulfurization.

  13. Rapid isolation of biomarkers for compound specific radiocarbon dating using high-performance liquid chromatography and flow injection analysis-atmospheric pressure chemical ionisation mass spectrometry.

    PubMed

    Smittenberg, Rienk H; Hopmans, Ellen C; Schouten, Stefan; Sinninghe Damsté, Jaap S

    2002-11-29

    Repeated semi-preparative normal-phase HPLC was performed to isolate selected biomarkers from sediment extracts for radiocarbon analysis. Flow injection analysis-mass spectrometry was used for rapid analysis of collected fractions to evaluate the separation procedure, taking only 1 min per fraction. In this way 100-1000 microg of glycerol dialkyl glycerol tetraethers, sterol fractions and chlorophyll-derived phytol were isolated from typically 100 g of marine sediment, i.e., in sufficient quantities for radiocarbon analysis, without significant carbon isotopic fractionation or contamination.

  14. Effect of parallel segmented flow chromatography on the height equivalent to a theoretical plate III--influence of the column length, particle diameter, and the molecular weight of the analyte on the efficiency gain.

    PubMed

    Gritti, Fabrice; Pynt, Jarrod; Soliven, Arianne; Dennis, Gary R; Shalliker, R Andrew; Guiochon, Georges

    2014-03-14

    The effects of column length on performance in segmented flow chromatography were tested. Column efficiencies were measured for 4.6mm I.D. 3, 5, 7.5 and 10 cm long columns packed with 3.0 μm Hypurity-C18 fully porous particles and of 4.6mm I.D. 5, 10, 15 and 25 cm long columns packed with 5 μm Hypersil GOLD C18 particles. For each column length and particle type, two different configurations were tested: (1) both the inlet and outlet column endfittings were standard and (2) the inlet endfitting was standard but the outlet endfitting allowed parallel segmentation of the exiting flow into a central and a peripheral coaxial region. The segmentation flow ratio was set at 45% (for 3 μm) and at 43% or 21% (for 5 μm). Four samples were used, naphthalene, toluene, butylbenzene, and insulin, which has a ten times smaller diffusion coefficient than the small molecules. The column performance for the low molecular weight compound is significantly improved at velocities above the optimum value when the outlet flow rate is segmented because longitudinal diffusion and mass transfer resistance of this compound in the stationary phase are negligible sources of band broadening at reduced linear velocities between 5 and 25. At high flow rate (4 mL/min), the long-range eddy dispersion terms are about 3.9, 3.2, 2.6, and 1.8h unit lower for the 3, 5, 7.5 and 10 cm long columns, respectively. The longer the column, the lower the efficiency improvement because the border effects are smaller. This result was not systematically observed for the columns packed with 5 μm particles because the transverse dispersion is larger. In contrast, the gain in column efficiency is marginal for insulin because the mass transfer mechanism of this compound is mostly controlled by the slow diffusivity of insulin across Hypurity-C18 particles.

  15. Comparison of Lateral Flow Assay, Kidney Inhibition Swab, and Liquid Chromatography-Tandem Mass Spectrometry for the Detection of Penicillin G Residues in Sow Urine.

    PubMed

    Shelver, Weilin L; Chakrabarty, Shubhashis; Smith, David J

    2017-03-01

    Sows (n = 126) were administered penicillin G; urine, collected at slaughter, was screened by kidney inhibition swab (KIS; 4 h testing time) and then stored at -80 °C (∼1200 days) until analysis by lateral flow assay (LF, ∼5 min testing time) and tandem quadrupole LC-MS/MS (TQ) analysis. The stability of penicillin in urine during storage was verified using TQ analyses. Quantitative results were well-correlated (R(2) = 0.98) with only a ∼10% decrease in penicillin concentration during the 3-year storage period. KIS retesting of stored samples returned results consistent with the original analyses. Lateral flow assay results were highly correlated with the KIS and TQ results. A KIS positive sample, which was not confirmed by TQ or LF, was assayed by Triple-TOF LC-MS to determine the cause of the apparent false positive. This study suggests LF can be used to quickly and efficiently screen for penicillin G residues before slaughter.

  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.

  17. Tubular collagen scaffolds with radial elasticity for hollow organ regeneration.

    PubMed

    Versteegden, Luuk R; van Kampen, Kenny A; Janke, Heinz P; Tiemessen, Dorien M; Hoogenkamp, Henk R; Hafmans, Theo G; Roozen, Edwin A; Lomme, Roger M; van Goor, Harry; Oosterwijk, Egbert; Feitz, Wout F; van Kuppevelt, Toin H; Daamen, Willeke F

    2017-04-01

    Tubular collagen scaffolds have been used for the repair of damaged hollow organs in regenerative medicine, but they generally lack the ability to reversibly expand in radial direction, a physiological characteristic seen in many native tubular organs. In this study, tubular collagen scaffolds were prepared that display a shape recovery effect and therefore exhibit radial elasticity. Scaffolds were constructed by compression of fibrillar collagen around a star-shaped mandrel, mimicking folds in a lumen, a typical characteristic of empty tubular hollow organs, such as ureter or urethra. Shape recovery effect was introduced by in situ fixation using a star-shaped mandrel, 3D-printed clamps and cytocompatible carbodiimide crosslinking. Prepared scaffolds expanded upon increase of luminal pressure and closed to the star-shaped conformation after removal of pressure. In this study, we applied this method to construct a scaffold mimicking the dynamics of human urethra. Radial expansion and closure of the scaffold could be iteratively performed for at least 1000 cycles, burst pressure being 132±22mmHg. Scaffolds were seeded with human epithelial cells and cultured in a bioreactor under dynamic conditions mimicking urination (pulse flow of 21s every 2h). Cells adhered and formed a closed luminal layer that resisted flow conditions. In conclusion, a new type of a tubular collagen scaffold has been constructed with radial elastic-like characteristics based on the shape of the scaffold, and enabling the scaffold to reversibly expand upon increase in luminal pressure. These scaffolds may be useful for regenerative medicine of tubular organs.

  18. Differentiating common causes of radial wrist pain.

    PubMed

    Shuaib, Waqas; Mohiuddin, Zia; Swain, Freddie R; Khosa, Faisal

    2014-09-01

    Radial wrist pain is a common patient complaint with a broad differential. Because treatment and prognosis differ, determining the underlying cause is key. This article reviews a case of intersection syndrome and compares it to other causes of radial wrist pain.

  19. Radial Correlations Between Two Quarks

    NASA Astrophysics Data System (ADS)

    Green, A. M.; Koponen, J.; Pennanen, P.; Michael, C.

    2002-04-01

    In nuclear many-body problems the short-range correlation between two nucleons is well described by the corresponding correlation in the two-body problem. Therefore, as a first step in any attempt at an analogous description of many-quark systems, it is necessary to know the two-quark correlation. With this in mind, we study the light quark distribution in a heavy-light meson with a static heavy quark. The charge and matter radial distributions of these heavy-light mesons are measured on a lattice with a light quark mass about that of the strange quark. Both distributions can be well fitted upto r ≈ 0.7 fm with the exponential form wi2 (r), where Wi(r) = A exp(-r/ri). For the charge(c) and matter(m) distributions rc ≈ 0.32(2)fm and rm ≈ 0.24(2)fm. We also discuss the normalisation of the total charge (defined to be unity in the continuum limit) and matter integrated over all space, finding 1.30(5) and 0.4(1) respectively for a lattice spacing ≈ 0.17 fm.

  20. Combination radial and thrust magnetic bearing

    NASA Technical Reports Server (NTRS)

    Blumenstock, Kenneth A. (Inventor)

    2002-01-01

    A combination radial and thrust magnetic bearing is disclosed that allows for both radial and thrust axes control of an associated shaft. The combination radial and thrust magnetic bearing comprises a rotor and a stator. The rotor comprises a shaft, and first and second rotor pairs each having respective rotor elements. The stator comprises first and second stator elements and a magnet-sensor disk. In one embodiment, each stator element has a plurality of split-poles and a corresponding plurality of radial force coils and, in another embodiment, each stator element does not require thrust force coils, and radial force coils are replaced by double the plurality of coils serving as an outer member of each split-pole half.

  1. Determination of low levels of methanol in crude oils by multi-dimensional gas chromatography (MDGC) using novel micro channel flow technology.

    PubMed

    Tipler, Andrew; Marotta, Lee; DiSanzo, Frank; Grecsek, Heidi

    2012-03-01

    The accurate and precise determination of methanol in crude oils at concentrations less than 10 ppm is of economic value to the petroleum industry. This report presents the optimization, results and long term performance of a flow switching device MDGC hardware, the Swafer™, for the rapid and precise analysis of methanol from approximately 0.4 ppm (w/w) to 1000 ppm. The use of low temperature injection and backflush technique decreases maintenance and increases sample throughput. The short term quantitative percent relative standard deviations at 1, 30 and 1000 ppm (w/w) methanol in crude oils are 5, 3 and 0.3, respectively. The MDGC procedure follows closely that described in ASTM D7059 for determination of crude oils; however, D7059 previously has not been evaluated at concentrations of less than 10 ppm. This work further extends the application of D7059 to concentrations of <10 ppm.

  2. 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

  3. The design of an air-cooled metallic high temperature radial turbine

    NASA Technical Reports Server (NTRS)

    Snyder, Philip H.; Roelke, Richard J.

    1988-01-01

    Recent trends in small advanced gas turbine engines call for higher turbine inlet temperatures. Advances in radial turbine technology have opened the way for a cooled metallic radial turbine capable of withstanding turbine inlet temperatures of 2500 F while meeting the challenge of high efficiency in this small flow size range. In response to this need, a small air-cooled radial turbine has been designed utilizing internal blade coolant passages. The coolant flow passage design is uniquely tailored to simultaneously meet rotor cooling needs and rotor fabrication constraints. The rotor flow-path design seeks to realize improved aerodynamic blade loading characteristics and high efficiency while satisfying rotor life requirements. An up-scaled version of the final engine rotor is currently under fabrication and, after instrumentation, will be tested in the warm turbine test facility at the NASA Lewis Research Center.

  4. 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.

  5. 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...

  6. The study of the influence of temperature and initial glucose concentration on the fermentation process in the presence of Saccharomyces cerevisiae yeast strain immobilized on starch gels by reversed-flow gas chromatography.

    PubMed

    Lainioti, G Ch; Kapolos, J; Koliadima, A; Karaiskakis, G

    2012-01-01

    The technique of reversed-flow gas chromatography (RFGC) was employed for the determination of the alcoholic fermentation phases and of kinetic parameters for free and immobilized cell systems, at different initial glucose concentrations and temperature values. In addition to this, due to its considerable advantages over other techniques, RFGC was used for the characterization of a new biocatalyst, yeast cells immobilized on starch gel, and especially wheat starch gel. Immobilization of wine yeast Saccharomyces cerevisiae AXAZ-1 was accomplished on wheat and corn starch gels in order to prepare new biocatalysts with great interest for the fermentation industry. The RFGC led with great accuracy, resulting from a literature review, to the determination of reaction rate constants and activation energies at each phase of the fermentation processes. A maximum value of rate constants was observed at initial glucose concentration of 205 g/L, where a higher number of yeast cells was observed. The increase of glucose concentrations had a negative influence on the growth of AXAZ-1 cells and rate constants were decreased. The decrease of fermentation temperature caused a substantial reduction in the viability of immobilized cells as well as in rate constant values. Activation energies of corn starch gel presented lower values than those of wheat starch gel. However, the two supports showed higher catalytic efficiency than free cell systems, proving that starch gels may act as a promoter of the catalytic activity of the yeast cells involved in the fermentation process.

  7. Tandem mass spectrometry with online high-flow reversed-phase extraction and normal-phase chromatography on silica columns with aqueous-organic mobile phase for quantitation of polar compounds in biological fluids.

    PubMed

    Deng, Yuzhong; Zhang, Hongwei; Wu, Jing-Tao; Olah, Timothy V

    2005-01-01

    In this work, high-flow online reversed-phase extraction was coupled with normal phase on silica columns with aqueous-organic mobile phase liquid chromatography/tandem mass spectrometry (LC/MS/MS) to quantify drug candidates in biological fluids. The orthogonal separation effect obtained from this configuration considerably reduced matrix effects and increased sensitivity for highly polar compounds as detected by selected reaction monitoring. This approach also significantly improved the robustness and limit of detection of the assays. An evaluation of this system was performed using a mixture of albuterol and bamethan in rat plasma. Assay validation demonstrated acceptable accuracy (< 8% difference) and precision (< 6% CV) for these model compounds. The system has been used for the quantitation of polar ionic compounds in biological fluids in support of drug discovery programs. This assay was used to analyze samples for a BMS proprietary compound (A) in a rat pharmacokinetic study and is shown as an example to demonstrate the precision, accuracy, and sufficient sensitivity of this system.

  8. LC-HR-MS/MS standard urine screening approach: Pros and cons of automated on-line extraction by turbulent flow chromatography versus dilute-and-shoot and comparison with established urine precipitation.

    PubMed

    Helfer, Andreas G; Michely, Julian A; Weber, Armin A; Meyer, Markus R; Maurer, Hans H

    2017-02-01

    Comprehensive urine screening for drugs and metabolites by LC-HR-MS/MS using Orbitrap technology has been described with precipitation as simple workup. In order to fasten, automate, and/or simplify the workup, on-line extraction by turbulent flow chromatography and a dilute-and-shoot approach were developed and compared. After chromatographic separation within 10min, the Q-Exactive mass spectrometer was run in full scan mode with positive/negative switching and subsequent data dependent acquisition mode. The workup approaches were validated concerning selectivity, recovery, matrix effects, process efficiency, and limits of identification and detection for typical drug representatives and metabolites. The total workup time for on-line extraction was 6min, for the dilution approach 3min. For comparison, the established urine precipitation and evaporation lasted 10min. The validation results were acceptable. The limits for on-line extraction were comparable with those described for precipitation, but lower than for dilution. Thanks to the high sensitivity of the LC-HR-MS/MS system, all three workup approaches were sufficient for comprehensive urine screening and allowed fast, reliable, and reproducible detection of cardiovascular drugs, drugs of abuse, and other CNS acting drugs after common doses.

  9. 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.

  10. Basic Principles of Chromatography

    NASA Astrophysics Data System (ADS)

    Ismail, Baraem; Nielsen, S. Suzanne

    Chromatography has a great impact on all areas of analysis and, therefore, on the progress of science in general. Chromatography differs from other methods of separation in that a wide variety of materials, equipment, and techniques can be used. [Readers are referred to references (1-19) for general and specific information on chromatography.]. This chapter will focus on the principles of chromatography, mainly liquid chromatography (LC). Detailed principles and applications of gas chromatography (GC) will be discussed in Chap. 29. In view of its widespread use and applications, high-performance liquid chromatography (HPLC) will be discussed in a separate chapter (Chap. 28). The general principles of extraction are first described as a basis for understanding chromatography.

  11. 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).

  12. Submarine radial vents on Mauna Loa Volcano, Hawaìi

    NASA Astrophysics Data System (ADS)

    Wanless, V. Dorsey; Garcia, M. O.; Trusdell, F. A.; Rhodes, J. M.; Norman, M. D.; Weis, Dominique; Fornari, D. J.; Kurz, M. D.; Guillou, Hervé

    2006-05-01

    A 2002 multibeam sonar survey of Mauna Loa's western flank revealed ten submarine radial vents and three submarine lava flows. Only one submarine radial vent was known previously. The ages of these vents are constrained by eyewitness accounts, geologic relationships, Mn-Fe coatings, and geochemical stratigraphy; they range from 128 years B.P. to possibly 47 ka. Eight of the radial vents produced degassed lavas despite eruption in water depths sufficient to inhibit sulfur degassing. These vents formed truncated cones and short lava flows. Two vents produced undegassed lavas that created "irregular" cones and longer lava flows. Compositionally and isotopically, the submarine radial vent lavas are typical of Mauna Loa lavas, except two cones that erupted alkalic lavas. He-Sr isotopes for the radial vent lavas follow Mauna Loa's evolutionary trend. The compositional and isotopic heterogeneity of these lavas indicates most had distinct parental magmas. Bathymetry and acoustic backscatter results, along with photography and sampling during four JASON2 dives, are used to produce a detailed geologic map to evaluate Mauna Loa's submarine geologic history. The new map shows that the 1877 submarine eruption was much larger than previously thought, resulting in a 10% increase for recent volcanism. Furthermore, although alkalic lavas were found at two radial vents, there is no systematic increase in alkalinity among these or other Mauna Loa lavas as expected for a dying volcano. These results refute an interpretation that Mauna Loa's volcanism is waning. The submarine radial vents and flows cover 29 km2 of seafloor and comprise a total volume of ˜2 × 109 m3 of lava, reinforcing the idea that submarine lava eruptions are important in the growth of oceanic island volcanoes even after they emerged above sea level.

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. Study on the radial composite piezoelectric ceramic transducer in radial vibration.

    PubMed

    Lin, Shuyu

    2007-03-01

    A new type of radial composite piezoelectric transducer in radial vibration is developed and analyzed. The radial composite transducer consists of a piezoelectric ceramic thin ring polarized in the thickness direction and a metal thin circular ring. They are connected together and excited to vibrate in the radial direction. The radial vibrations of a piezoelectric ceramic thin ring and a metal thin circular ring are analyzed, respectively. Their radial electro-mechanical equivalent circuits are obtained. Based on the electro-mechanical equivalent circuits and using the boundary conditions between the piezoelectric ceramic thin ring and the metal thin circular ring in the radial direction, the electro-mechanical equivalent circuit of the radial composite piezoelectric transducer is derived out and the resonance frequency equation is obtained. The relationship between the resonance frequency and the geometrical dimensions of the transducer is analyzed. Some radial composite piezoelectric transducers are designed and manufactured. The resonance frequencies and the anti-resonance frequencies, the electro-mechanical equivalent circuit parameters are measured. The effective electro-mechanical coupling coefficient and the mechanical quality factor are calculated. It is illustrated that the measured radial resonance frequencies are in good agreement with the theoretical results from the resonance frequency equation.

  18. A MSE Polarimetry diagnostic for the measurement of radial electric fields on the HSX stellarator

    NASA Astrophysics Data System (ADS)

    Dobbins, T. J.; Kumar, S. T. A.; Anderson, F. S. B.; Anderson, D. T.

    2016-10-01

    The radial electric field in HSX has been measured using the Charge Exchange Recombination Spectroscopy. These impurity ion flow measurements could not resolve a large positive radial electric field (40-50 kV/m) near the core of the HSX plasma, predicted by neoclassical codes. A dual PEM (Photo Elastic Modulator) MSE polarimetry system has been designed for direct measurement of the radial electric field in the HSX plasma. The polarimetry design has been optimized to get a maximum change in polarization angle from an electric field while still providing good spatial resolution. It is expected that a radial electric field as small as 7 kV/m can be detected. The initial results of the system on an available port will be presented. The choice and design of the optics for the optimal viewing port will also be presented. This work is supported by US DOE Grant DE-FG02-93ER54222.

  19. Radial construction of an arterial wall.

    PubMed

    Greif, Daniel M; Kumar, Maya; Lighthouse, Janet K; Hum, Justine; An, Andrew; Ding, Ling; Red-Horse, Kristy; Espinoza, F Hernan; Olson, Lorin; Offermanns, Stefan; Krasnow, Mark A

    2012-09-11

    Some of the most serious diseases involve altered size and structure of the arterial wall. Elucidating how arterial walls are built could aid understanding of these diseases, but little is known about how concentric layers of muscle cells and the outer adventitial layer are assembled and patterned around endothelial tubes. Using histochemical, clonal, and genetic analysis in mice, here we show that the pulmonary artery wall is constructed radially, from the inside out, by two separate but coordinated processes. One is sequential induction of successive cell layers from surrounding mesenchyme. The other is controlled invasion of outer layers by inner layer cells through developmentally regulated cell reorientation and radial migration. We propose that a radial signal gradient controls these processes and provide evidence that PDGF-B and at least one other signal contribute. Modulation of such radial signaling pathways may underlie vessel-specific differences and pathological changes in arterial wall size and structure.

  20. The fundamental definition of ``radial velocity''

    NASA Astrophysics Data System (ADS)

    Lindegren, Lennart; Dravins, Dainis

    2003-04-01

    Accuracy levels of metres per second require the fundamental concept of ``radial velocity'' for stars and other distant objects to be examined, both as a physical velocity, and as measured by spectroscopic and astrometric techniques. Already in a classical (non-relativistic) framework the line-of-sight velocity component is an ambiguous concept, depending on whether, e.g., the time of light emission (at the object) or that of light detection (by the observer) is used for recording the time coordinate. Relativistic velocity effects and spectroscopic measurements made inside gravitational fields add further complications, causing wavelength shifts to depend, e.g., on the transverse velocity of the object and the gravitational potential at the source. Aiming at definitions that are unambiguous at accuracy levels of 1 m s-1, we analyse different concepts of radial velocity and their interrelations. At this accuracy level, a strict separation must be made between the purely geometric concepts on one hand, and the spectroscopic measurement on the other. Among the geometric concepts we define kinematic radial velocity, which corresponds most closely to the ``textbook definition'' of radial velocity as the line-of-sight component of space velocity; and astrometric radial velocity, which can be derived from astrometric observations. Consistent with these definitions, we propose strict definitions also of the complementary kinematic and astrometric quantities, namely transverse velocity and proper motion. The kinematic and astrometric radial velocities depend on the chosen spacetime metric, and are accurately related by simple coordinate transformations. On the other hand, the observational quantity that should result from accurate spectroscopic measurements is the barycentric radial-velocity measure. This is independent of the metric, and to first order equals the line-of-sight velocity. However, it is not a physical velocity, and cannot be accurately transformed to a

  1. Mathematical interpretation of radial shearing interferometers.

    PubMed

    Malacara, D

    1974-08-01

    The procedure for computing a radial shearing interferometric pattern is given. The interferometric pattern is analyzed to obtain the wavefront shape. Restricting the discussion to wavefronts having rotational symmetry, we give two different methods of finding the wavefront. One approach is to scan along a diameter of the interferometric pattern and the other is to examine the shape of the fringes. The relative sensitivity of a radial shearing interferometer with respect to that of a Twyman-Green interferometer is also analyzed.

  2. Elbow dislocation with irreparable fracture radial head

    PubMed Central

    Tanna, Dilip

    2013-01-01

    Background: Treatment of elbow dislocation with irreparable radial head fracture needs replacement of radial head to achieve stability of elbow. An alternate method in cases of elbow dislocation with radial head fracture can be resection of radial head with repair of medial collateral ligament. We report a retrospective analysis of cases of elbow dislocation with irreparable radial head treated by excision head of radius and repair of MCL. Materials and Methods: Nine patients of elbow dislocation with associated irreparable fractures of the head of the radius were included in this analysis (6 F:3 M, Age: 35-47 years). Radial head excision was done through the lateral approach and MCL was sutured using no 3 Ethibond using medial approach. Above elbow plaster was given for 6 weeks and gradual mobilization was done thereafter. All patients were assessed at final followup using Mayo elbow performance score (MEPS). Results: Mean followup was 19.55 ± 7.12 months (range 14-36 months). There was no extension deficit when compared to opposite side with mean range of flexion of 138.8° ± 6.97° (range 130 -145°). Mean pronation was 87.7° ± 4.4° (range 80-90°) and mean supination was 87.7 ± 4.62° (range 80-90°). The mean MEPS was 98.8 ± 3.33 (range 90-100). No patient had pain, sensory complaints, subluxation or redislocation. All were able to carry out their daily activities without disability. Conclusion: Radial head excision with MCL repair is an acceptable option for treatment of patients with elbow dislocation and irreparable radial head fracture. PMID:23798760

  3. Radial averages of astigmatic TEM images.

    PubMed

    Fernando, K Vince

    2008-10-01

    The Contrast Transfer Function (CTF) of an image, which modulates images taken from a Transmission Electron Microscope (TEM), is usually determined from the radial average of the power spectrum of the image (Frank, J., Three-dimensional Electron Microscopy of Macromolecular Assemblies, Oxford University Press, Oxford, 2006). The CTF is primarily defined by the defocus. If the defocus estimate is accurate enough then it is possible to demodulate the image, which is popularly known as the CTF correction. However, it is known that the radial average is somewhat attenuated if the image is astigmatic (see Fernando, K.V., Fuller, S.D., 2007. Determination of astigmatism in TEM images. Journal of Structural Biology 157, 189-200) but this distortion due to astigmatism has not been fully studied or understood up to now. We have discovered the exact mathematical relationship between the radial averages of TEM images with and without astigmatism. This relationship is determined by a zeroth order Bessel function of the first kind and hence we can exactly quantify this distortion in the radial averages of signal and power spectra of astigmatic images. The argument to this Bessel function is similar to an aberration function (without the spherical aberration term) except that the defocus parameter is replaced by the differences of the defoci in the major and minor axes of astigmatism. The ill effects due this Bessel function are twofold. Since the zeroth order Bessel function is a decaying oscillatory function, it introduces additional zeros to the radial average and it also attenuates the CTF signal in the radial averages. Using our analysis, it is possible to simulate the effects of astigmatism in radial averages by imposing Bessel functions on idealized radial averages of images which are not astigmatic. We validate our theory using astigmatic TEM images.

  4. 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.

  5. Radial glia and somal translocation of radial neurons in the developing cerebral cortex.

    PubMed

    Nadarajah, Bagirathy

    2003-07-01

    A series of recent studies have demonstrated that radial glia are neural precursors in the developing cerebral cortex. These studies have further implied that these cells are the sole precursor constituents of the dorsal forebrain ventricular zone that generate the projection neurons of the cortex. In view of these new findings, this review discusses radial neurons, a progeny of cortical neurons that are generated by radial glia and adopt somal translocation as the mode of migration.

  6. [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.

  7. 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.

  8. 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

  9. 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.

  10. The reversed-flow gas chromatography technique as a tool for the study of the evaporation retardation of SO2 and (CH3)2S from water by soluble surfactants.

    PubMed

    Sevastos, D; Kotsalos, E; Koliadima, A

    2017-02-01

    In the present work the evaporation retardation of SO2 and (CH3)2S (=DMS) from water by soluble surfactants was studied by the Reversed-Flow Gas Chromatography (R.F.G.C.) technique. Using suitable mathematical analysis, rate coefficients, kc, for the transfer of SO2 and DMS from pure or artificial sea water to the atmospheric environment were determined in the presence or the absence of surfactants. The efficiency of the three surfactants used (CTAB, TRITON X-100 and SDS) to retard the evaporation rate of SO2 and DMS from water was estimated by the decrease of the kc values in the presence of the three surfactants, compared to those in the absence of surfactants. The more efficient surfactant for the retardation evaporation of SO2 from both the pure and the artificial sea water was found to be the cationic CTAB surfactant, as the maximum decreases of the kc values were found to be 4.61×10(-3)cms(-1) (number of films, n=1) and 3.07×10(-3)cms(-1) (n=3), respectively. On the other hand, more efficient surfactant for the retardation evaporation of DMS from pure water was found to be the non-ionic TRITON X-100, in which the decrease of the kc value was estimated to be 18.20×10(-3)cms(-1) (n=3) and from artificial sea water the cationic CTAB surfactant in which the decrease of the kc value was found to be 8.24×10(-3)cms(-1) (n=3). Finally, the precision of the R.F.G.C. method in studying the retardation effect of various surfactants in the transfer of SO2 and DMS from the water body to the atmosphere is estimated (mean value 96.69%), and the experimental values of kc are compared with those given in the literature.

  11. Elimination of diastereomer interference to determine Telcagepant (MK-0974) in human plasma using on-line turbulent-flow technology and off-line solid-phase extraction coupled with liquid chromatography/tandem mass spectrometry.

    PubMed

    Xu, Yang; Willson, Kenneth J; Anderson, Melanie D G; Musson, Donald G; Miller-Stein, Cynthia M; Woolf, Eric J

    2009-06-01

    To eliminate the diastereomer interference on Telcagepant (MK-0974) determination during clinical study support, on-line high turbulent-flow liquid chromatography (HTLC) methods, HTLC-A and HTLC-B that covered dynamic range of 0.5-500 nM and 5-5000 nM, respectively, were developed. To meet the requirement of rapid assay transfer among multiple laboratories and analysts, a solid-phase extraction (SPE) assay was derived from the existing HTLC-B assay under the same dynamic range. The on-line HTLC assays were achieved through direct injection of plasma samples, extraction of analyte with a Cohesive C18 column (50 mm x 0.5 mm, 50 microm), followed by HPLC separation on a FluoPhase RP column (100 mm x 2.1 mm, 5 microm) and MS/MS detection. The off-line SPE assay used Waters Oasis HLB microElution plate to extract the analytes from plasma matrix before injecting on a FluoPhase RP column (150 mm x 2.1 mm, 5 microm) for LC-MS/MS analysis. Under both on-line and off-line assay conditions, the diastereomer 1c was chromatographically separated from MK-0974. Cross-validation with the pooled samples demonstrated that both on-line and off-line assays provided comparable data with a difference of < 2.6%. The assays were proved to be specific, accurate and reliable, and have been used to support multiple clinical studies. The pros and cons of on-line and off-line assays with regard to man power involved in sample preparation, total analysis time, carryover, cost efficiency, and the requirement for assay transfer are discussed.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. A mini axial and a permanent maglev radial heart pump.

    PubMed

    Qian, Kun-Xi; Ru, Wei-Min; Wang, Hao; Jing, Teng

    2007-05-31

    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.

  18. Auroral evidence of radial transport at Jupiter during January 2014

    NASA Astrophysics Data System (ADS)

    Gray, R. L.; Badman, S. V.; Bonfond, B.; Kimura, T.; Misawa, H.; Nichols, J. D.; Vogt, M. F.; Ray, L. C.

    2016-10-01

    We present Jovian auroral observations from the 2014 January Hubble Space Telescope (HST) campaign and investigate the auroral signatures of radial transport in the magnetosphere alongside contemporaneous radio and Hisaki EUV data. HST FUV auroral observations on day 11 show, for the first time, a significantly superrotating polar spot poleward of the main emission on the dawnside. The spot transitions from the polar to main emission region in the presence of a locally broad, bright dawnside main emission feature and two large equatorward emission features. Such a configuration of the main emission region is also unreported to date. We interpret the signatures as part of a sequence of inward radial transport processes. Hot plasma inflows from tail reconnection are thought to flow planetward and could generate the superrotating spot. The main emission feature could be the result of flow shears from prior hot inflows. Equatorward emissions are observed. These are evidence of hot plasma injections in the inner magnetosphere. The images are thought to be part of a prolonged period of reconnection. Radio emissions measured by Wind suggest that hectometric (HOM) and non-Io decametric (DAM) signatures are associated with the sequence of auroral signatures, which implies a global magnetospheric disturbance. The reconnection and injection interval can continue for several hours.

  19. 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.

  20. 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 Hα behaviour.

  1. Radial spoke proteins of Chlamydomonas flagella

    PubMed Central

    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.

    2007-01-01

    Summary 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

  2. Digital artery pseudoaneurysm in a patient with previous radial artery harvest

    PubMed Central

    Plant, Mathew A; Panchapakesan, Vivek

    2011-01-01

    A post-traumatic pseudoaneurysm in the ulnar digital artery of the thumb in a patient with compromised vascularity due to a previous harvest of the ipsilateral radial artery is reported. To the authors’ knowledge, the present case is the first such description of a pseudoaneurysm in the digital artery of a patient with compromised collateral blood flow. PMID:23204888

  3. Effect of Curved Radial Vane Cavity Arrangements on Predicted Inter-Turbine Burner (ITB) Performance

    DTIC Science & Technology

    2007-06-01

    other material viscous boundary layers. All surface meshes were properties were set to default values, constructed using GRIDGEN 23]. These surface meshes...Inc., GRIDGEN VI5, 2004. 24. AFLR3D, www.erc.msstate.edu. Radial Cavity a) b) MainnFlows’Quick Quench) Figure 4b and 4c. Schematics of the CRV

  4. Separation techniques: Chromatography

    PubMed Central

    Coskun, Ozlem

    2016-01-01

    Chromatography is an important biophysical technique that enables the separation, identification, and purification of the components of a mixture for qualitative and quantitative analysis. Proteins can be purified based on characteristics such as size and shape, total charge, hydrophobic groups present on the surface, and binding capacity with the stationary phase. Four separation techniques based on molecular characteristics and interaction type use mechanisms of ion exchange, surface adsorption, partition, and size exclusion. Other chromatography techniques are based on the stationary bed, including column, thin layer, and paper chromatography. Column chromatography is one of the most common methods of protein purification. PMID:28058406

  5. 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)

  6. Using a box instead of a column for process chromatography.

    PubMed

    Ghosh, Raja

    2016-10-14

    Columns with relatively short bed-height to diameter ratios are frequently used for process-scale chromatography applications such as biopharmaceutical purification. Non-uniform flow distribution within such columns could result in broad and poorly resolved eluted peaks, which could in turn affect purity, recovery and productivity of the process. Different strategies centered on improved column header design have been proposed for addressing this problem. This paper describes a radically different approach, i.e. the use of a chromatography box (or chromato-box) instead of a column, for addressing the challenges posed by flow mal-distribution in process-scale, packed-bed chromatography devices. The design of the chromatography box devices used in this study is based on a laterally-fed membrane chromatography (or LFMC) device, that has been described and discussed in several recent papers. The performances of two chromatography box devices were compared with their equivalent columns in terms of sharpness and asymmetry of flow-through and eluted peaks, number of theoretical plates per metre, and peak resolution in binary and ternary protein separations. In each of the above comparisons, the chromatography box devices performed better than their equivalent columns, clearly indicating their potential as an alternative in process-scale chromatography applications.

  7. Radial head fracture associated with posterior interosseous nerve injury.

    PubMed

    Terra, Bernardo Barcellos; Sassine, Tannus Jorge; Lima, Guilherme de Freitas; Rodrigues, Leandro Marano; Padua, David Victoria Hoffmann; Nadai, Anderson de

    2016-01-01

    Fractures of the radial head and radial neck correspond to 1.7-5.4% of all fractures and approximately 30% may present associated injuries. In the literature, there are few reports of radial head fracture with posterior interosseous nerve injury. This study aimed to report a case of radial head fracture associated with posterior interosseous nerve injury.

  8. Precise Near-Infrared Radial Velocities

    NASA Astrophysics Data System (ADS)

    Plavchan, Peter; Gao, P.; Bottom, M.; Davison, C.; Mills, S.; Ciardi, D. R.; Brinkworth, C.; Tanner, A. M.; Beichman, C. A.; Catanzarite, J.; Crawford, S.; Wallace, J.; Mennesson, B.; Johnson, J. A.; White, R. J.; Anglada-Escudé, G.; von Braun, K.; Walp, B.; Vasisht, G.; Kane, S. R.; Prato, L. A.; NIRRVs

    2014-01-01

    We present precise radial velocity time-series from a 2.3 micron pilot survey to detect exoplanets around red, low mass, and young stars. We use the CSHELL spectrograph with an isotopic methane absorption gas cell for common optical path relative wavelength calibration at the NASA InfraRed Telescope Facility. We present an overview of our Nelder-Mead simplex optimization pipeline for extracting radial velocities. We will also present first light data at 1.6 microns from a near-infrared fiber scrambler used in tandem with our gas cell and CSHELL at IRTF. The fiber scrambler makes use of non-circular core fibers to stabilize the illumination of the slit and echelle grating against changes in seeing, focus, guiding and other sources of systematic radial velocity noise, complementing the wavelength calibration of a gas cell.

  9. 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.

  10. Dispersion-free radial transmission lines

    DOEpatents

    Caporaso, George J.; Nelson, Scott D.

    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.

  11. Radial anisotropy ambient noise tomography of volcanoes

    NASA Astrophysics Data System (ADS)

    Mordret, Aurélien; Rivet, Diane; Shapiro, Nikolai; Jaxybulatov, Kairly; Landès, Matthieu; Koulakov, Ivan; Sens-Schönfelder, Christoph

    2016-04-01

    The use of ambient seismic noise allows us to perform surface-wave tomography of targets which could hardly be imaged by other means. The frequencies involved (~ 0.5 - 20 s), somewhere in between active seismic and regular teleseismic frequency band, make possible the high resolution imaging of intermediate-size targets like volcanic edifices. Moreover, the joint inversion of Rayleigh and Love waves dispersion curves extracted from noise correlations allows us to invert for crustal radial anisotropy. We present here the two first studies of radial anisotropy on volcanoes by showing results from Lake Toba Caldera, a super-volcano in Indonesia, and from Piton de la Fournaise volcano, a hot-spot effusive volcano on the Réunion Island (Indian Ocean). We will see how radial anisotropy can be used to infer the main fabric within a magmatic system and, consequently, its dominant type of intrusion.

  12. Image scanning microscopy with radially polarized light

    NASA Astrophysics Data System (ADS)

    Xiao, Yun; Zhang, Yunhai; Wei, Tongda; Huang, Wei; Shi, Yaqin

    2017-03-01

    In order to improve the resolution of image scanning microscopy, we present a method based on image scanning microscopy and radially polarized light. According to the theory of image scanning microscopy, we get the effective point spread function of image scanning microscopy with the longitudinal component of radially polarized light and a 1 AU detection area, and obtain imaging results of the analyzed samples using this method. Results show that the resolution can be enhanced by 7% compared with that in image scanning microscopy with circularly polarized light, and is 1.54-fold higher than that in confocal microscopy with a pinhole of 1 AU. Additionally, the peak intensity of ISM is 1.54-fold higher than that of a confocal microscopy with a pinhole of 1 AU. In conclusion, the combination of the image scanning microscopy and the radially polarized light could improve the resolution, and it could realize high-resolution and high SNR imaging at the same time.

  13. Chitosan-based membrane chromatography for protein adsorption and separation.

    PubMed

    Liu, Yezhuo; Feng, Zhicheng; Shao, Zhengzhong; Chen, Xin

    2012-08-01

    A chitosan-based membrane chromatography was set up by using natural chitosan/carboxymethylchitosan (CS/CMCS) blend membrane as the matrix. The dynamic adsorption property for protein (lysozyme as model protein) was detailed discussed with the change in pore size of the membrane, the flow rate and the initial concentration of the feed solution, and the layer of membrane in membrane stack. The best dynamic adsorption capacity of lysozyme on the CS/CMCS membrane chromatography was found to be 15.3mg/mL under the optimal flow conditions. Moreover, the CS/CMCS membrane chromatography exhibited good repeatability and reusability with the desorption efficiency of ~90%. As an application, lysozyme and ovalbumin were successfully separated from their binary mixture through the CS/CMCS membrane chromatography. This implies that such a natural chitosan-based membrane chromatography may have great potential on the bioseparation field in the future.

  14. Magnetic resonance microimaging and numerical simulations of velocity fields inside enlarged flow cells used for coupled NMR microseparations.

    PubMed

    Zhang, Xiaofeng; Webb, Andrew G

    2005-03-01

    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 approximately 1 microL. 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.

  15. Mapping radial features in Saturn's rings

    NASA Astrophysics Data System (ADS)

    Tiscareno, Matthew S.; Harris, B. E.

    2013-10-01

    We have carried out a comprehensive survey of the best Cassini ISS data of Saturn's main rings for the purpose of cataloguing all observed spiral density waves, spiral bending waves, and other radial and quasi-radial ring structure. Our survey has revealed a number of new features, including the first known resonant waves raised by Enceladus and Hyperion, thus increasing the number of points at which the local surface density and viscosity of the rings can be measured (cf. Tiscareno et al. 2007, Icarus). We also catalogue several wave-like features whose cause is unknown. Although images of the rings taken by the Imaging Science Subsystem (ISS) are not nominally as high-resolution as the best stellar and radio occultations, they are capable of superior signal-to-noise because of the co-adding inherent in converting a 2-D image into a 1-D "radial scan." In this common technique, as many as a thousand pixels at a given radial distance from Saturn are combined to produce a single characteristic brightness for each radial location. This process suppresses local structure, azimuthal structure, and random noise, all of which commonly decrease the sensitivity of high-resolution occultations, and causes ISS to be the optimal Cassini instrument for detecting a certain class of low-amplitude features. Finally, we employ wavelet techniques (cf. Tiscareno et al. 2007, Icarus) to elucidate subtle periodic and quasi-periodic features in the radial scan data. We will present our results in the context of a ranking of known perturbations in the rings by their resonant torque (updating Lissauer and Cuzzi 1982, AJ). We will identify the strongest expected perturbations that do not appear, and discuss whether the absence is likely to reflect a real limit of ring responsiveness, or (as with previous observations) to reflect sensitivity limits.

  16. Plasma Signatures of Radial Field Power Dropouts

    SciTech Connect

    Lucek, E.A.; Horbury, T.S.; Balogh, A.; McComas, D.J.

    1998-10-04

    A class of small scale structures, with a near-radial magnetic field and a drop in magnetic field fluctuation power, have recently been identified in the polar solar wind. An earlier study of 24 events, each lasting for 6 hours or more, identified no clear plasma signature. In an extension of that work, radial intervals lasting for 4 hours or more (89 in total), have been used to search for a statistically significant plasma signature. It was found that, despite considerable variations between intervals, there was a small but significant drop, on average, in plasma temperature, density and {beta} during these events.

  17. Plasma signatures of radial field power dropouts

    SciTech Connect

    Lucek, E.A.; Balogh, A.; Horbury, T.S.; McComas, D.J.

    1999-06-01

    A class of small scale structures, with a near-radial magnetic field and a drop in magnetic field fluctuation power, have recently been identified in the polar solar wind. An earlier study of 24 events, each lasting for 6 hours or more, identified no clear plasma signature. In an extension of that work, radial intervals lasting for 4 hours or more (89 in total), have been used to search for a statistically significant plasma signature. It was found that, despite considerable variations between intervals, there was a small but significant drop, on average, in plasma temperature, density and {beta} during these events. {copyright} {ital 1999 American Institute of Physics.}

  18. Radial Acceleration Relation in Rotationally Supported Galaxies

    NASA Astrophysics Data System (ADS)

    McGaugh, Stacy S.; Lelli, Federico; Schombert, James M.

    2016-11-01

    We report a correlation between the radial acceleration traced by rotation curves and that predicted by the observed distribution of baryons. The same relation is followed by 2693 points in 153 galaxies with very different morphologies, masses, sizes, and gas fractions. The correlation persists even when dark matter dominates. Consequently, the dark matter contribution is fully specified by that of the baryons. The observed scatter is small and largely dominated by observational uncertainties. This radial acceleration relation is tantamount to a natural law for rotating galaxies.

  19. Reconstruction for Type IV Radial Polydactyly.

    PubMed

    Wall, Lindley B; Goldfarb, Charles A

    2015-09-01

    Type IV radial polydactyly represents a thumb with an extra proximal and distal phalanx. Assessment of the thumb for surgical reconstruction includes observing thumb function, evaluating thumb size and stability, and assessing the first web space. Reconstruction includes excision of the smaller thumb, typically the radial thumb, and re-creating thumb stability and alignment by addressing tendon insertion and joint orientation. Although surgical results are satisfying and complications are uncommon, additional surgical intervention may be required over time owing to thumb malalignment or instability.

  20. Radial Acceleration Relation in Rotationally Supported Galaxies.

    PubMed

    McGaugh, Stacy S; Lelli, Federico; Schombert, James M

    2016-11-11

    We report a correlation between the radial acceleration traced by rotation curves and that predicted by the observed distribution of baryons. The same relation is followed by 2693 points in 153 galaxies with very different morphologies, masses, sizes, and gas fractions. The correlation persists even when dark matter dominates. Consequently, the dark matter contribution is fully specified by that of the baryons. The observed scatter is small and largely dominated by observational uncertainties. This radial acceleration relation is tantamount to a natural law for rotating galaxies.

  1. 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.

  2. Radial excitations of current-carrying vortices

    NASA Astrophysics Data System (ADS)

    Hartmann, Betti; Michel, Florent; Peter, Patrick

    2017-04-01

    We report on the existence of a new type of cosmic string solutions in the Witten model with U (1) × U (1) symmetry. These solutions are superconducting with radially excited condensates that exist for both gauged and ungauged currents. Our results suggest that these new configurations can be macroscopically stable, but microscopically unstable to radial perturbations. Nevertheless, they might have important consequences for the network evolution and particle emission. We discuss these effects and their possible signatures. We also comment on analogies with non-relativistic condensed matter systems where these solutions may be observable.

  3. 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.

  4. 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.

  5. 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.

  6. A novel method for analytically solving a radial advection-dispersion equation

    NASA Astrophysics Data System (ADS)

    Lai, Keng-Hsin; Liu, Chen-Wuing; Liang, Ching-Ping; Chen, Jui-Sheng; Sie, Bing-Ruei

    2016-11-01

    An analytical solution for solute transport in a radial flow field has a variety of practical applications in the study of the transport in push-pull/divergent/convergent flow tracer tests, aquifer remediation by pumping and aquifer storage and recovery. However, an analytical solution for radial advective-dispersive transport has been proven very difficult to develop and relatively few in subsurface hydrology have made efforts to do so, because variable coefficients in the governing partial differential equations. Most of the solutions for radial advective-dispersive transport presented in the literature have generally been solved semi-analytically with the final concentration values being obtained with the help of a numerical Laplace inversion. This study presents a novel solution strategy for analytically solving the radial advective-dispersive transport problem. A Laplace transform with respect to the time variable and a generalized integral transform technique with respect to the spatial variable are first performed to convert the transient governing partial differential equations into an algebraic equation. Subsequently, the algebraic equation is solved using simple algebraic manipulations, easily yielding the solution in the transformed domain. The solution in the original domain is ultimately obtained by successive applications of the Laplace and corresponding generalized integral transform inversions. A convergent flow tracer test is used to demonstrate the robustness of the proposed method for deriving an exact analytical solution to the radial advective-dispersive transport problem. The developed analytical solution is verified against a semi-analytical solution taken from the literature. The results show perfect agreement between our exact analytical solution and the semi-analytical solution. The solution method presented in this study can be applied to create more comprehensive analytical models for a great variety of radial advective

  7. 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)

  8. 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.

  9. 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,…

  10. Geodesic acoustic modes in tokamak plasmas with a radial equilibrium electric field

    SciTech Connect

    Zhou, Deng

    2015-09-15

    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.

  11. GCFR radial blanket and shield experiment

    SciTech Connect

    Muckenthaler, F.J.; Hull, J.L.; Manning, J.J.

    1980-12-01

    This report presents integral neutron flux, energy spectra, and gamma-ray heating measurements made for the Radial Blanket and Shield Experiment at the ORNL Tower Shielding Facility as part of a continuing Gas Cooled Fast Breeder Reactor program. The experimental configurations were divided into four basic segments: a spectrum modifier inserted into the Tower Shielding Reactor II beam; blanket slabs consisting of either ThO/sub 2/ or UO/sub 2/ placed directly behind the spectrum modifier; an inner radial shield behind the blankets; and an outer radial shield to complete the mockup. The segments were added in sequence, with selected measurements made within and beyond each segment. The integral experiment was performed to provide verification of calculational methods and nuclear data used in designing a radial shield for the GCFR and determining the effectiveness of the design. The ThO/sub 2/ blanket measurements were needed to bracket the uncertainties in the nuclear cross sections for calculating both the neutron transmission through the blanket and the gamma-ray heating rates within the blanket. Measurements with a UO/sub 2/ blanket were included both as a reference for the ThO/sub 2/ analysis, neutron transmission through UO/sub 2/ having been successfully calculated in previous experiments, and to provide comparison information for other breeder reactor designs.

  12. Extended foil capacitor with radially spoked electrodes

    DOEpatents

    Foster, James C.

    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.

  13. Radial-Gap Motor for Ship Propulsion

    NASA Astrophysics Data System (ADS)

    Yanamoto, Toshiyuki; Yokoyama, Minoru

    The KHI team has developed radial gap high-temperature superconducting (HTS) motors of three sizes, 1 MW-class, 3 MW, and 20 MW, to be used for electric propulsion systems for ships. The volumetric torque density of the assembled 3 MW HTS motor was recorded at 40 kNm/m3 in the load test; the world's highest in the class.

  14. 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.

  15. 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)…

  16. MMICs with Radial Probe Transitions to Waveguides

    NASA Technical Reports Server (NTRS)

    Samoska, Lorene; Chattopadhyay, Goutam; Pukala, David; Soria, Mary; Fung, King Man; Gaier, Todd; Radisic, Vesna; Lai, Richard

    2009-01-01

    A document presents an update on the innovation reported in Integrated Radial Probe Transition From MMIC to Waveguide (NPO-43957), NASA Tech Briefs Vol. 31, No. 5 (May 2007), page 38. To recapitulate: To enable operation or testing of a monolithic microwave integrated circuit (MMIC), it is necessary to mount the MMIC in a waveguide package that typically has cross-sectional waveguide dimensions of the order of a few hundred microns. A radial probe transition between an MMIC operating at 340 GHz and a waveguide had been designed (but not yet built and tested) to be fabricated as part of a monolithic unit that would include the MMIC. The radial probe could readily be integrated with an MMIC amplifier because the design provided for fabrication of the transition on a substrate of the same material (InP) and thickness (50 m) typical of substrates of MMICs that can operate above 300 GHz. As illustrated in the updated document by drawings, photographs, and plots of test data, the concept has now been realized by designing, fabricating, and testing several MMIC/radial- probe integrated-circuit chips and designing and fabricating a waveguide package to contain each chip.

  17. P wave azimuthal and radial anisotropy of the Hokkaido subduction zone

    NASA Astrophysics Data System (ADS)

    Niu, Xiongwei; Zhao, Dapeng; Li, Jiabiao; Ruan, Aiguo

    2016-04-01

    We present the first three-dimensional P wave radial anisotropy tomography of the Hokkaido subduction zone, as well as P wave azimuthal anisotropy and S wave tomography, which are determined by inverting 298,430 P wave and 233,934 S wave arrival times from 14,245 local earthquakes recorded by 344 seismic stations. Our results reveal significant velocity heterogeneity, seismic anisotropy, and upwelling flows beneath the study region. In the mantle wedge, prominent low-velocity (low-V) anomalies exhibit trench-normal fast-velocity directions (FVDs) and a negative radial anisotropy (i.e., vertical velocity > horizontal velocity), which may reflect upwelling mantle flows. Fan-shaped FVDs are found at depths of 65-90 km, and a detailed 3-D mantle flow pattern is revealed, which may be caused by a combination of oblique subduction of the Pacific plate and collision of the Kuril arc with the Honshu arc beneath southern Hokkaido. The radial anisotropy changes at ~100 km depth, which may reflect variations in temperature and fluid conditions there. The subducting Pacific slab exhibits a positive radial anisotropy (i.e., horizontal velocity > vertical velocity), which may reflect the original fossil anisotropy when the Pacific plate formed at the mid-ocean ridge.

  18. Radial wave crystals: radially periodic structures from anisotropic metamaterials for engineering acoustic or electromagnetic waves.

    PubMed

    Torrent, Daniel; Sánchez-Dehesa, José

    2009-08-07

    We demonstrate that metamaterials with anisotropic properties can be used to develop a new class of periodic structures that has been named radial wave crystals. They can be sonic or photonic, and wave propagation along the radial directions is obtained through Bloch states like in usual sonic or photonic crystals. The band structure of the proposed structures can be tailored in a large amount to get exciting novel wave phenomena. For example, it is shown that acoustical cavities based on radial sonic crystals can be employed as passive devices for beam forming or dynamically orientated antennas for sound localization.

  19. 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.

  20. Phosphopeptide separation using radially aligned titania nanotubes on titanium wire.

    PubMed

    Wijeratne, Aruna B; Wijesundera, Dharshana N; Paulose, Maggie; Ahiabu, Ivy Belinda; Chu, Wei-Kan; Varghese, Oomman K; Greis, Kenneth D

    2015-06-03

    Phosphoproteomic analysis offers a unique view of cellular function and regulation in biological systems by providing global measures of a key cellular regulator in the form of protein phosphorylation. Understanding the phosphorylation changes between normal and diseased cells or tissues offers a window into the mechanism of disease and thus potential targets for therapeutic intervention. A key step in these studies is the enrichment of phosphorylated peptides that are typically separated and analyzed by using liquid chromatography mass spectrometry. The mesoporous titania beads/particles (e.g., Titansphere TiO2 beads from GL Sciences Inc., Japan) that are widely used for phosphopeptide enrichment are expensive and offer very limited opportunities for further performance improvement. Titiania nanotube arrays have shown promising characteristics for phosphopeptide separation. Here we report a proof-of-concept study to evaluate the efficacy of nanotubes on Ti-wire for phosphoproteomics research. We used titania nanotubes radially grown on titanium wires as well as the commercial beads to separate phosphopeptides generated from mouse liver complex tissue extracts. Our studies revealed that the nanotubes on metal wire provide comparable efficacy for enrichment of phophopeptides and offer an ease of use advantage versus mesoporous beads, thus having the potential to become a low cost and more practical material/methodology for phosphopeptide enrichment in biological studies.

  1. 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.

  2. Turbulent jet manipulation using two unsteady azimuthally separated radial minijets.

    PubMed

    Yang, H; Zhou, Y; So, R M C; Liu, Y

    2016-07-01

    The active manipulation of a turbulent round jet is experimentally investigated based on the injection of two radial unsteady minijets, prior to the issue of the main jet. The parametric study is conducted for the mass flow ratio Cm of the minijets to the main jet, and the ratio fe/f0 of the minijet frequency to the preferred-mode frequency of the main jet. It is found that the decay rate of the jet centreline mean velocity could be greatly increased if the two minijets are separated azimuthally by an angle θ=60°, instead of by θ=180°. This increase is a consequence of the flapping motion of the jet column, and the formation process and generation mechanism of this flapping motion are unveiled by careful analysis of the experimental data.

  3. 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.

  4. Interplay between Mach cone and radial expansion in jet events

    NASA Astrophysics Data System (ADS)

    Tachibana, Y.; Hirano, T.

    2016-12-01

    We study the hydrodynamic response to jet propagation in the expanding QGP and investigate how the particle spectra after the hydrodynamic evolution of the QGP reflect it. We perform simulations of the space-time evolution of the QGP in gamma-jet events by solving (3+1)-dimensional ideal hydrodynamic equations with source terms. Mach cone is induced by the jet energy deposition and pushes back the radial flow of the expanding background. Especially in the case when the jet passage is off-central one, the number of particles emitted in the direction of the push back decreases. This is the signal including the information about the formation of the Mach cone and the jet passage in the QGP fluid.

  5. 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.

  6. A radial non-uniform helicon equilibrium discharge model

    NASA Astrophysics Data System (ADS)

    Cheng, Yu-Guo; Cheng, Mou-Sen; Wang, Mo-Ge; Li, Xiao-Kang

    2014-10-01

    Helicon discharges have attracted great attention in the electric propulsion community in recent years. To acquire the equilibrium properties, a self-consistent model is developed, which combines the helicon/Trivelpiece—Gould (TG) waves-plasma interaction mechanism and the plasma flow theory under the confinement of the magnetic field. The calculations reproduce the central peak density phenomenon observed in the experiments. The results show that when operating in the wave coupling mode, high magnetic field strength B0 results in the deviation of the central density versus B0 from the linear relationship, while the density rise becomes flatter as the radiofrequency (rf) input power Prf grows, and the electron temperature Te radial profile is mainly determined by the characteristic of the rf energy deposition. The model could provide suggestions in choosing the B0 and Prf for medium power helicon thrusters.

  7. New Measurements of Radial Mode Eigenfrequencies

    NASA Astrophysics Data System (ADS)

    Laske, G.; Masters, G.; Dziewonski, A. M.

    2001-12-01

    Radial mode eigenfrequencies are commonly thought to be measured with great ease and precision. The reason for this is that these modes have no geographic pattern so one should be able to measure frequencies from a spectrum observed at any station in the world. Yet, radial modes often seem inconsistent with spherical Earth models that fit all other mode frequencies. It turns out that radial modes are sometimes strongly coupled. The strongest coupling is predicted to be with l=2 modes which is caused by the Earth's hydrostatic ellipticity and aspherical structure of harmonic degree 2. In such cases, mode-coupling due to ellipticity alone can cause a frequency shift for the radial modes by more than 4 microHz. Given that mode frequencies can be measured to within 0.1 microHz, this shift is significant, and some singlets of l=2 modes have indeed been misidentified as the radial mode in the past. Including the spectra of the June 23, 2001 Southern Peru Earthquake we have re-analyzed radial mode eigenfrequencies and present a mode dataset that is internally more consistent than previous ones. We construct spherical Earth models that are consistent with our new data, the Earth's mass and moment of inertia and the current best estimates of ``Reference Normal Mode Data'' (available on the Reference Earth Model web site: //mahi.ucsd.edu/Gabi/rem.html). We seek the smallest perturbation to PREM but update the Q-structure as well as the depths of the upper mantle discontinuities (418~km and 660~km as first order discontinuities; 520~km as change in gradient). The best fitting 1D model is transversely isotropic but we also show isotropic models that fit the data to within their errors. We show that the 220~km discontinuity is not required in the isotropic model but that there exists a trade-off between high shear-velocities in the lid and a low-density zone beneath it. We also investigate ways of truncating transverse isotropy without the 220.

  8. Autumn Leaf Chromatography.

    ERIC Educational Resources Information Center

    Scharmann, Lawrence C.

    1984-01-01

    Describes an experiment designed to introduce students to chromatographic techniques. Also describes a teacher demonstration in which leaves obtained during the spring and fall are analyzed using chromatography. Procedures for both the experiment and the demonstration are outlined. (JN)

  9. 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 μm 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.

  10. Lattice radial quantization: 3D Ising

    NASA Astrophysics Data System (ADS)

    Brower, R. C.; Fleming, G. T.; Neuberger, H.

    2013-04-01

    Lattice radial quantization is introduced as a nonperturbative method intended to numerically solve Euclidean conformal field theories that can be realized as fixed points of known Lagrangians. As an example, we employ a lattice shaped as a cylinder with a 2D Icosahedral cross-section to discretize dilatations in the 3D Ising model. Using the integer spacing of the anomalous dimensions of the first two descendants (l = 1, 2), we obtain an estimate for η = 0.034 (10). We also observed small deviations from integer spacing for the 3rd descendant, which suggests that a further improvement of our radial lattice action will be required to guarantee conformal symmetry at the Wilson-Fisher fixed point in the continuum limit.

  11. New radial engine technology from Kongsburg

    SciTech Connect

    Mowill, R.J.; Strom, S.

    1983-01-01

    The first engine of a new family of high performance, rugged radial turbines is presented. The new single shaft 1500 kW site rated KG3 is built upon extensive experience from the field proven KG2 of the same nominal power. The KG3 is being developed both as a simple cycle and recuperated engine providing specific fuel consumptions in the range of 0.29 to 0.19 kg/kW-hr (0.47 to 0.32 lbs/hp-hr). The new Kongsberg engine makes use of a high specific speed high pressure ratio centrifugal compressor combined with a very high tip speed uncooled radial turbine to obtain optimized aerodynamic matching. Several novel design features ar described.

  12. Radial spline assembly for antifriction bearings

    NASA Technical Reports Server (NTRS)

    Moore, Jerry H. (Inventor)

    1993-01-01

    An outer race carrier is constructed for receiving an outer race of an antifriction bearing assembly. The carrier in turn is slidably fitted in an opening of a support wall to accommodate slight axial movements of a shaft. A plurality of longitudinal splines on the carrier are disposed to be fitted into matching slots in the opening. A deadband gap is provided between sides of the splines and slots, with a radial gap at ends of the splines and slots and a gap between the splines and slots sized larger than the deadband gap. With this construction, operational distortions (slope) of the support wall are accommodated by the larger radial gaps while the deadband gaps maintain a relatively high springrate of the housing. Additionally, side loads applied to the shaft are distributed between sides of the splines and slots, distributing such loads over a larger surface area than a race carrier of the prior art.

  13. 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.

  14. Simple proposal for radial 3D needlets

    NASA Astrophysics Data System (ADS)

    Durastanti, C.; Fantaye, Y.; Hansen, F.; Marinucci, D.; Pesenson, I. Z.

    2014-11-01

    We present here a simple construction of a wavelet system for the three-dimensional ball, which we label radial 3D needlets. The construction envisages a data collection environment in which an observer located at the center of the ball is surrounded by concentric spheres with the same pixelization at different radial distances, for any given resolution. The system is then obtained by weighting the projector operator built on the corresponding set of eigenfunctions and performing a discretization step which turns out to be computationally very convenient. The resulting wavelets can be shown to have very good localization properties in the real and harmonic domain; their implementation is computationally very convenient, and they allow for exact reconstruction as they form a tight frame system. Our theoretical results are supported by an extensive numerical analysis.

  15. Radial localization of odors by human newborns.

    PubMed

    Rieser, J; Yonas, A; Wikner, K

    1976-09-01

    To study sensitivity to radial location of an odor source, 20 human newborns, ranging from 16 to 130 hours of age, were presented with a small amount of ammonium hydroxide. The odor source was placed near the nose slightly to the left or right of midline, with its position randomized over repeated trails. Direction of headturn with respect to the odor location and diffuse motor activity were scored from the videotape recordings of the newborns' behavior. It was found that as a group, the newborns turned away from the odor source more frequently than they turned toward it. The tendency to turn away from the odor was stronger in infants who displayed less motor activity after the response. Newborns also exhibited a right bias in the direction of the head movements. It is concluded that a spatially appropriate avoidance response is present in the neonate and that the newborn is innately sensitive to the radial location of an odor.

  16. 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.

  17. Varying deformation patterns in central Tibet revealed by radial anisotropy tomography

    NASA Astrophysics Data System (ADS)

    Zhang, Heng; Zhao, Dapeng; Yu, Chunquan; Zhao, Junmeng

    2016-05-01

    P wave radial anisotropy tomography of the upper mantle beneath the central Tibetan plateau is derived using a large number of traveltime data of teleseismic events. Our results show a prominent high-velocity (high-V) zone which is separated by a low-velocity (low-V) anomaly beneath the Himalayan block, extending to ~33°N, and a low-V zone down to ~300 km depth beneath the northern Qiangtang block. The upper mantle beneath northern Qiangtang exhibits a significant positive radial anisotropy (i.e., horizontal Vp > vertical Vp), implying lateral material flow rather than material upwelling in the upper mantle. In the central part of the study region, a prominent high-V zone exists at depths of 150 to 300 km and exhibits a negative radial anisotropy (i.e., horizontal Vp < vertical Vp), reflecting the subducting Indian lithospheric mantle. Variations of shear wave splitting in this region revealed by previous studies may be attributed to the low-V layer above the Indian lithospheric mantle. A high-V zone with a positive radial anisotropy is located beneath the southern Lhasa block, which is interpreted to be the northward underthrusting Indian lithospheric mantle. Multilayer radial anisotropy is detected beneath southern Tibet, which may reflect a complex deformation pattern there.

  18. Crustal radial anisotropy in Northeast China and its implications for the regional tectonic extension

    NASA Astrophysics Data System (ADS)

    Guo, Zhen; Yang, Yingjie; Chen, Y. John

    2016-10-01

    We obtain high-resolution Rayleigh and Love wave phase velocity maps from ambient noise tomography using data recorded by NECESSArray in Northeast China. The resulting radial anisotropic model from the joint inversion of Rayleigh and Love wave dispersion curves reveals strong relationship between the crustal radial anisotropy and tectonic provinces, that is, strong positive anisotropy (Vsh > Vsv) beneath the Songliao Basin and weak radial anisotropy beneath the Xinmeng Belt and Changbaishan Region. The Songliao Basin experienced widespread crustal extension during the late Mesozoic. We interpret the lower crustal anisotropy beneath the Songliao Basin as a result of ductile deformation during the rifting stage, which may lead to the alignment of anisotropic minerals and the observed strong radial anisotropy at present. In the northern Songliao Basin, where thick syn-rift and post-rift sediments (≥4 km) are believed to be present, we observe a broader lateral distribution of anisotropy with stronger amplitude compared with the southern basin. We suggest that the broader distribution of crustal radial anisotropy in the northern basin could be the consequence of outward lower crustal flow driven by the sedimentary loading during the post-rift stage, which is also proposed by previous numerical modeling.

  19. 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.

  20. Wavelets, Fractals, and Radial Basis Functions

    DTIC Science & Technology

    2007-11-02

    of Signal Processing. San Diego, CA: Aca- demic, 1998. [13] G. Strang and T. Q. Nguyen, Wavelets and Filter Banks . Cambridge, MA: Wellesley-Cambridge...localization, multiresolution, radial basis functions, re- finement filter , scaling functions, self-similarity, splines, tempered distributions, two-scale...one linear constraint per basis function, and the corresponding linear system of equations is invertible under relatively mild conditions [11]. The

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. WAVE-VORTEX MODE COUPLING IN ASTROPHYSICAL ACCRETION DISKS UNDER COMBINED RADIAL AND VERTICAL STRATIFICATION

    SciTech Connect

    Salhi, A.; Lehner, T.; Godeferd, F.; Cambon, C.

    2013-07-10

    We examine accretion disk flow under combined radial and vertical stratification utilizing a local Cartesian (or ''shearing box'') approximation. We investigate both axisymmetric and nonaxisymmetric disturbances with the Boussinesq approximation. Under axisymmetric disturbances, a new dispersion relation is derived. It reduces to the Solberg-Hoieland criterion in the case without vertical stratification. It shows that, asymptotically, stable radial and vertical stratification cannot induce any linear instability; Keplerian flow is accordingly stable. Previous investigations strongly suggest that the so-called bypass concept of turbulence (i.e., that fine-tuned disturbances of any inviscid smooth shear flow can reach arbitrarily large transient growth) can also be applied to Keplerian disks. We present an analysis of this process for three-dimensional plane-wave disturbances comoving with the shear flow of a general rotating shear flow under combined stable radial and vertical rotation. We demonstrate that large transient growth occurs for K{sub 2}/k{sub 1} >> 1 and k{sub 3} = 0 or k{sub 1} {approx} k{sub 3}, where k{sub 1}, K{sub 2}, and k{sub 3} are the azimuthal, radial, and vertical components of the initial wave vector, respectively. By using a generalized ''wave-vortex'' decomposition of the disturbance, we show that the large transient energy growth in a Keplerian disk is mainly generated by the transient dynamics of the vortex mode. The analysis of the power spectrum of total (kinetic+potential) energy in the azimuthal or vertical directions shows that the contribution coming from the vortex mode is dominant at large scales, while the contribution coming from the wave mode is important at small scales. These findings may be confirmed by appropriate numerical simulations in the high Reynolds number regime.

  6. Heat Transfer Experiments in the Internal Cooling Passages of a Cooled Radial Turbine Rotor

    NASA Technical Reports Server (NTRS)

    Johnson, B. V.; Wagner, J. H.

    1996-01-01

    An experimental study was conducted (1) to experimentally measure, assess and analyze the heat transfer within the internal cooling configuration of a radial turbine rotor blade and (2) to obtain heat transfer data to evaluate and improve computational fluid dynamics (CFD) procedures and turbulent transport models of internal coolant flows. A 1.15 times scale model of the coolant passages within the NASA LERC High Temperature Radial Turbine was designed, fabricated of Lucite and instrumented for transient beat transfer tests using thin film surface thermocouples and liquid crystals to indicate temperatures. Transient heat transfer tests were conducted for Reynolds numbers of one-fourth, one-half, and equal to the operating Reynolds number for the NASA Turbine. Tests were conducted for stationary and rotating conditions with rotation numbers in the range occurring in the NASA Turbine. Results from the experiments showed the heat transfer characteristics within the coolant passage were affected by rotation. In general, the heat transfer increased and decreased on the sides of the straight radial passages with rotation as previously reported from NASA-HOST-sponsored experiments. The heat transfer in the tri-passage axial flow region adjacent to the blade exit was relatively unaffected by rotation. However, the heat transfer on one surface, in the transitional region between the radial inflow passage and axial, constant radius passages, decreased to approximately 20 percent of the values without rotation. Comparisons with previous 3-D numerical studies indicated regions where the heat transfer characteristics agreed and disagreed with the present experiment.

  7. CARMENES: data flow

    NASA Astrophysics Data System (ADS)

    Caballero, J. A.; Guàrdia, J.; López del Fresno, M.; Zechmeister, M.; de Juan, E.; Alonso-Floriano, F. J.; Amado, P. J.; Colomé, J.; Cortés-Contreras, M.; García-Piquer, Á.; Gesa, L.; de Guindos, E.; Hagen, H.-J.; Helmling, J.; Hernández Castaño, L.; Kürster, M.; López-Santiago, J.; Montes, D.; Morales Muñoz, R.; Pavlov, A.; Quirrenbach, A.; Reiners, A.; Ribas, I.; Seifert, W.; Solano, E.

    2016-07-01

    CARMENES, the new Calar Alto spectrograph especially built for radial-velocity surveys of exoearths around M dwarfs, is a very complicated system. For reaching the goal of 1 m/s radial-velocity accuracy, it is appropriate not only to monitor stars with the best observing procedure, but to monitor also the parameters of the CARMENES subsystems and safely store all the engineer and science data. Here we describe the CARMENES data flow from the different subsystems, through the instrument control system and pipeline, to the virtual-observatory data server and astronomers.

  8. Visualization study of flow in axial flow inducer.

    NASA Technical Reports Server (NTRS)

    Lakshminarayana, B.

    1972-01-01

    A visualization study of the flow through a three ft dia model of a four bladed inducer, which is operated in air at a flow coefficient of 0.065, is reported in this paper. The flow near the blade surfaces, inside the rotating passages, downstream and upstream of the inducer is visualized by means of smoke, tufts, ammonia filament, and lampblack techniques. Flow is found to be highly three dimensional, with appreciable radial velocity throughout the entire passage. The secondary flows observed near the hub and annulus walls agree with qualitative predictions obtained from the inviscid secondary flow theory.

  9. 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.

  10. 14 CFR 73.5 - Bearings; radials; miles.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Bearings; radials; miles. 73.5 Section 73.5 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRSPACE SPECIAL USE AIRSPACE General § 73.5 Bearings; radials; miles. (a) All bearings and radials in this...

  11. 14 CFR 71.7 - Bearings, radials, and mileages.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Bearings, radials, and mileages. 71.7 Section 71.7 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... REPORTING POINTS § 71.7 Bearings, radials, and mileages. All bearings and radials in this part are true...

  12. 14 CFR 71.7 - Bearings, radials, and mileages.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Bearings, radials, and mileages. 71.7 Section 71.7 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... REPORTING POINTS § 71.7 Bearings, radials, and mileages. All bearings and radials in this part are true...

  13. 14 CFR 73.5 - Bearings; radials; miles.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Bearings; radials; miles. 73.5 Section 73.5 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRSPACE SPECIAL USE AIRSPACE General § 73.5 Bearings; radials; miles. (a) All bearings and radials in this...

  14. 14 CFR 71.7 - Bearings, radials, and mileages.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Bearings, radials, and mileages. 71.7 Section 71.7 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... REPORTING POINTS § 71.7 Bearings, radials, and mileages. All bearings and radials in this part are true...

  15. 14 CFR 71.7 - Bearings, radials, and mileages.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Bearings, radials, and mileages. 71.7 Section 71.7 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... REPORTING POINTS § 71.7 Bearings, radials, and mileages. All bearings and radials in this part are true...

  16. 14 CFR 73.5 - Bearings; radials; miles.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Bearings; radials; miles. 73.5 Section 73.5 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRSPACE SPECIAL USE AIRSPACE General § 73.5 Bearings; radials; miles. (a) All bearings and radials in this...

  17. 14 CFR 73.5 - Bearings; radials; miles.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Bearings; radials; miles. 73.5 Section 73.5 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRSPACE SPECIAL USE AIRSPACE General § 73.5 Bearings; radials; miles. (a) All bearings and radials in this...

  18. 14 CFR 71.7 - Bearings, radials, and mileages.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Bearings, radials, and mileages. 71.7 Section 71.7 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... REPORTING POINTS § 71.7 Bearings, radials, and mileages. All bearings and radials in this part are true...

  19. 14 CFR 73.5 - Bearings; radials; miles.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Bearings; radials; miles. 73.5 Section 73.5 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRSPACE SPECIAL USE AIRSPACE General § 73.5 Bearings; radials; miles. (a) All bearings and radials in this...

  20. Effect of Inhomogeneous Flow on K-H Turbulence

    NASA Astrophysics Data System (ADS)

    Vasquez, Gabriela; Lin, Dong; Sen, Sudip; Scale, Wayne; Petulante, Nelson

    2017-01-01

    We study the effect of inhomogeneous flow on the Kelvin-Helmholz instability and turbulence. The inhomogeneous flow includes both flow shear and flow curvature. The effect of flow curvature (second radial derivative of flow) is shown to have significant effect in controlling the turbulence level contrary to the usual prediction that flow shear (first radial derivative of flow) alone controls the turbulence level. The detail result of this simulation will be reported. Work in this work is supported by the DOE grant DE-SC0016397.

  1. 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.

  2. Remotely detected NMR for the characterization of flow and fast chromatographic separations using organic polymer monoliths.

    PubMed

    Teisseyre, Thomas Z; Urban, Jiri; Halpern-Manners, Nicholas W; Chambers, Stuart D; Bajaj, Vikram S; Svec, Frantisek; Pines, Alexander

    2011-08-01

    An application of remotely detected magnetic resonance imaging is demonstrated for the characterization of flow and the detection of fast, small molecule separations within hypercrosslinked polymer monoliths. The hyper-cross-linked monoliths exhibited excellent ruggedness, with a transit time relative standard deviation of less than 2.1%, even after more than 300 column volumes were pumped through at high pressure and flow. Magnetic resonance imaging enabled high-resolution intensity and velocity-encoded images of mobile phase flow through the monolith. The images confirm that the presence of a polymer monolith within the capillary disrupts the parabolic laminar flow profile that is characteristic of mobile phase flow within an open tube. As a result, the mobile phase and analytes are equally distributed in the radial direction throughout the monolith. Also, in-line monitoring of chromatographic separations of small molecules at high flow rates is shown. The coupling of monolithic chromatography columns and NMR provides both real-time peak detection and chemical shift information for small aromatic molecules. These experiments demonstrate the unique power of magnetic resonance, both direct and remote, in studying chromatographic processes.

  3. Liquid cooled counter flow turbine bucket

    DOEpatents

    Dakin, James T.

    1982-09-21

    Means and a method are provided whereby liquid coolant flows radially outward through coolant passages in a liquid cooled turbine bucket under the influence of centrifugal force while in contact with countercurrently flowing coolant vapor such that liquid is entrained in the flow of vapor resulting in an increase in the wetted cooling area of the individual passages.

  4. RADIALLY MAGNETIZED PROTOPLANETARY DISK: VERTICAL PROFILE

    SciTech Connect

    Russo, Matthew; Thompson, Christopher

    2015-11-10

    This paper studies the response of a thin accretion disk to an external radial magnetic field. Our focus is on protoplanetary disks (PPDs), which are exposed during their later evolution to an intense, magnetized wind from the central star. A radial magnetic field is mixed into a thin surface layer, wound up by the disk shear, and pushed downward by a combination of turbulent mixing and ambipolar and ohmic drift. The toroidal field reaches much greater strengths than the seed vertical field that is usually invoked in PPD models, even becoming superthermal. Linear stability analysis indicates that the disk experiences the magnetorotational instability (MRI) at a higher magnetization than a vertically magnetized disk when both the effects of ambipolar and Hall drift are taken into account. Steady vertical profiles of density and magnetic field are obtained at several radii between 0.06 and 1 AU in response to a wind magnetic field B{sub r} ∼ (10{sup −4}–10{sup −2})(r/ AU){sup −2} G. Careful attention is given to the radial and vertical ionization structure resulting from irradiation by stellar X-rays. The disk is more strongly magnetized closer to the star, where it can support a higher rate of mass transfer. As a result, the inner ∼1 AU of a PPD is found to evolve toward lower surface density. Mass transfer rates around 10{sup −8} M{sub ⊙} yr{sup −1} are obtained under conservative assumptions about the MRI-generated stress. The evolution of the disk and the implications for planet migration are investigated in the accompanying paper.

  5. Radial velocity measurements in the F corona

    NASA Astrophysics Data System (ADS)

    Beavers, W. I.; Eitter, J. J.; Carr, P. H.; Cook, B. C.

    1980-05-01

    A photoelectric radial velocity spectrometer was employed at the February 26, 1979 total solar eclipse in an attempt to detect motion in the F corona. Multiple dip features were recorded in scans made at points 3.2 and 4.3 solar radii west of the sun. By employing simple dynamic models these observations may be interpreted as evidence of the following two separate components of dust in the inner regions of the solar system: dust moving in prograde orbits outside the region beginning at about four solar radii from the sun, and dust falling into the sun with velocities from about 50 to 250 km/s.

  6. Self-stabilizing radial face seal

    NASA Technical Reports Server (NTRS)

    Etsion, I. (Inventor)

    1981-01-01

    A self-stabilizing radial face seal comprises an axial member and a primary seal ring juxtapositioned to a seal seat. At least one primary seal ring and seal seat unit is affixed to the axial member so as to rotate with it. The primary seal ring has a front face which opposes a face of the seal seat. The seal has both high-pressure and low-pressure regions of fluid, and seal seat is provided with a porous ring-like circumferential structure in the face of the seal seat opposite the front face of the primary seal ring.

  7. Unsteady Specific Work and Isentropic Efficiency of a Radial Turbine Driven by Pulsed Detonations

    DTIC Science & Technology

    2012-06-14

    rotating detonation combustor RDE = rotating detonation engine SDC = steady deflagration combustor SiC = silicon carbide TDLAS = tunable diode...region of interest. Therefore, silicon carbide ( SiC ) seed particles (1-2 μm in size) have been used for seeding combustion flow fields. SiC filaments...Appendix F includes preliminary GT28 radial turbine inlet and exit flowfield measurements using high-speed cameras and silicon - carbide seed particles

  8. A numerical study of the temperature field in a cooled radial turbine rotor

    NASA Technical Reports Server (NTRS)

    Hamed, A.; Baskharone, E.; Tabakoff, W.

    1977-01-01

    The three dimensional temperature distribution in the cooled rotor of a radial inflow turbine is determined numerically using the finite element method. Through this approach, the complicated geometries of the hot rotor and coolant passage surfaces are handled easily, and the temperatures are determined without loss of accuracy at these convective boundaries. Different cooling techniques with given coolant to primary flow ratios are investigated, and the corresponding rotor temperature fields are presented for comparison.

  9. A numerical inversion of a the Laplace transform solution to radial dispersion in a porous medium.

    USGS Publications Warehouse

    Moench, A.F.; Ogata, A.

    1981-01-01

    A special form of the numerical inversion of the Laplace transform described by Stehfest (1970) is applied to the transformed solution of dispersion in a radial flow system in a porous medium. The inversion is extremely simple to use because the weighting coefficients depend only on the number of terms used in the computation and not upon the transform solution as required by most numerical inversion techniques.-from Authors

  10. Bilateral high radial nerve compressions: a case report.

    PubMed

    Chuangsuwanich, A; Muangsombut, S; Sangruchi, T

    2000-06-01

    A 40-year-old woman with bilateral high radial nerve compressions by non-traumatic cause was reported. It occurred first at the right radial nerve which was explored after a period of investigation and conservative treatment. Two constricted sites 2.0 cm apart of the right radial nerve crossed by branches of the radial collateral artery beneath the lateral head of the triceps were found. The constricted sites including tissue in between was resected and replaced with a sural nerve graft. One year later the patient had the same episode on the left side. The operative finding was the same as the previous one. Sural nerve graft was performed after neurolysis had failed. The patient's normal radial nerve function returned in one year. This is the first reported case in the literature of bilateral high radial nerve compressions by branches of the radial collateral artery.

  11. Validation of noninvasive MOEMS-assisted measurement system based on CCD sensor for radial pulse analysis.

    PubMed

    Malinauskas, Karolis; Palevicius, Paulius; Ragulskis, Minvydas; Ostasevicius, Vytautas; Dauksevicius, Rolanas

    2013-04-22

    Examination of wrist radial pulse is a noninvasive diagnostic method, which occupies a very important position in Traditional Chinese Medicine. It is based on manual palpation and therefore relies largely on the practitioner's subjective technical skills and judgment. Consequently, it lacks reliability and consistency, which limits practical applications in clinical medicine. Thus, quantifiable characterization of the wrist pulse diagnosis method is a prerequisite for its further development and widespread use. This paper reports application of a noninvasive CCD sensor-based hybrid measurement system for radial pulse signal analysis. First, artery wall deformations caused by the blood flow are calibrated with a laser triangulation displacement sensor, following by the measurement of the deformations with projection moiré method. Different input pressures and fluids of various viscosities are used in the assembled artificial blood flow system in order to test the performance of laser triangulation technique with detection sensitivity enhancement through microfabricated retroreflective optical element placed on a synthetic vascular graft. Subsequently, the applicability of double-exposure whole-field projection moiré technique for registration of blood flow pulses is considered: a computational model and representative example are provided, followed by in vitro experiment performed on a vascular graft with artificial skin atop, which validates the suitability of the technique for characterization of skin surface deformations caused by the radial pulsation.

  12. 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.

  13. Micellar Electrokinetic Chromatography

    NASA Astrophysics Data System (ADS)

    Bald, Edward; Kubalczyk, Paweł

    Since the introduction of micellar electrokinetic chromatography by Terabe, several authors have paid attention to the fundamental characteristics of this separation method. In this chapter the theoretical and practical aspects of resolution optimization, as well as the effect of different separation parameters on the migration behavior are discussed. These among others include fundamentals of separation, retention factor and resolution equation, efficiency, selectivity, and various surfactants and additives. Initial conditions for method development and instrumental approaches such as mass spectrometry detection are also mentioned covering the proposals for overcoming the difficulties arising from the coupling micellar electrokinetic chromatography with mass spectrometry detection.

  14. Micellar liquid chromatography

    NASA Astrophysics Data System (ADS)

    Basova, Elena M.; Ivanov, Vadim M.; Shpigun, Oleg A.

    1999-12-01

    Background and possibilities of practical applications of micellar liquid chromatography (MLC) are considered. Various retention models in MLC, the effects of the nature and concentration of surfactants and organic modifiers, pH, temperature and ionic strength on the MLC efficiency and selectivity are discussed. The advantages and limitations of MLC are demonstrated. The performance of MLC is critically evaluated in relationship to the reversed-phase HPLC and ion-pair chromatography. The potential of application of MLC for the analysis of pharmaceuticals including that in biological fluids and separation of inorganic anions, transition metal cations, metal chelates and heteropoly compounds is described. The bibliography includes 146 references.

  15. Thermal analysis of a fully wet porous radial fin with natural convection and radiation using the spectral collocation method

    NASA Astrophysics Data System (ADS)

    Khani, F.; Darvishi, M. T.; Gorla, R. S.. R.; Gireesha, B. J.

    2016-05-01

    Heat transfer with natural convection and radiation effect on a fully wet porous radial fin is considered. The radial velocity of the buoyancy driven flow at any radial location is obtained by applying Darcy's law. The obtained non-dimensionalized ordinary differential equation involving three highly nonlinear terms is solved numerically with the spectral collocation method. In this approach, the dimensionless temperature is approximated by Chebyshev polynomials and discretized by Chebyshev-Gausse-Lobatto collocation points. A particular algorithm is used to reduce the nonlinearity of the conservation of energy equation. The present analysis characterizes the effect of ambient temperature in different ways and it provides a better picture regarding the effect of ambient temperature on the thermal performance of the fin. The profiles for temperature distributions and dimensionless base heat flow are obtained for different parameters which influence the heat transfer rate.

  16. Core Radial Electric Field and Transport in Wendelstein 7-X Plasmas

    NASA Astrophysics Data System (ADS)

    Pablant, Novimir

    2016-10-01

    Results from the investigation of core transport and the role of the radial electric field profile (Er) in the first operational phase of the Wendelstein 7-X (W7-X) stellarator are presented. In stellarator plasmas, the details of the Er profile are expected to have a strong effect on both the particle and heat fluxes. Neoclassical particle fluxes are not intrinsically ambipolar, which leads to the formation of a radial electric field that enforces ambipolarity. The radial electric field is closely related to the perpendicular plasma flow (u⊥) through the force balance equation. This allows the radial electric field to be inferred from measurements of the perpendicular flow velocity from the x-ray imaging crystal spectrometer (XICS) and correlation reflectometry diagnostics. Large changes in the perpendicular rotation, on the order of Δu⊥ 5km /s (ΔEr 12kV / m), have been observed within a set of experiments where the heating power was stepped down from 2 MW to 0.6 MW . These experiments are examined in detail to explore the relationship between, heating power, response of the temperature and density profiles and the response of the radial electric field. Estimations of the core transport are based on power balance and utilize electron temperature (Te) profiles from the ECE and Thomson scattering, electron density profiles (ne) from interferometry and Thomson scattering, ion temperature (Ti) profiles from XICS, along with measurements of the total stored energy and radiated power. Also described are a set core impurity confinement experiments and results. Impurity confinement has been investigated through the injection of trace amount of argon impurity gas at the plasma edge in conjunction with measurements of the density of various ionization states of argon from the XICS and High Efficiency eXtreme-UV Overview Spectrometer (HEXOS) diagnostics. Finally the inferred Er and heat flux profiles are compared to initial neoclassical calculations using measured

  17. Dropwise Condensation on a Radial Gradient Surface

    NASA Astrophysics Data System (ADS)

    Macner, Ashley; Daniel, Susan; Steen, Paul

    2013-11-01

    In transient dropwise condensation from steam onto a cool surface, distributions of drops evolve by nucleation, growth, and coalescence. This study examines how surface functionalization affects drop growth and coalescence. Surfaces are treated by silanization to deliver either a spatially uniform contact-angle (hydrophilic, neutral, and hydrophobic) or a radial gradient of contact-angles. The time evolution of number-density and associated drop-size distributions are reported. For a typical condensation experiment on a uniform angle surface, the number-density curves show two regimes: an initial increase in number-density as a result of nucleation and a subsequent decrease in number-density as a result of larger scale coalescence events. Without a removal mechanism, the fractional coverage, regardless of treatment, approaches unity. For the same angle-surface, the associated drop-size distributions progress through four different shapes along the growth curve. In contrast, for a radial gradient surface where removal by sweeping occurs, the number-density increases and then levels off to a value close to the maximum number-density that is well below unity coverage and only two shapes of distributions are observed. Implications for heat transfer will be discussed. This work was supported by a NASA Office of the Chief Technologist's Space Technology Research Fellowship.

  18. A radial transmission line material measurement apparatus

    SciTech Connect

    Warne, L.K.; Moyer, R.D.; Koontz, T.E.; Morris, M.E.

    1993-05-01

    A radial transmission line material measurement sample apparatus (sample holder, offset short standards, measurement software, and instrumentation) is described which has been proposed, analyzed, designed, constructed, and tested. The purpose of the apparatus is to obtain accurate surface impedance measurements of lossy, possibly anisotropic, samples at low and intermediate frequencies (vhf and low uhf). The samples typically take the form of sections of the material coatings on conducting objects. Such measurements thus provide the key input data for predictive numerical scattering codes. Prediction of the sample surface impedance from the coaxial input impedance measurement is carried out by two techniques. The first is an analytical model for the coaxial-to-radial transmission line junction. The second is an empirical determination of the bilinear transformation model of the junction by the measurement of three full standards. The standards take the form of three offset shorts (and an additional lossy Salisbury load), which have also been constructed. The accuracy achievable with the device appears to be near one percent.

  19. Combining Transit and Radial Velocity Data

    NASA Astrophysics Data System (ADS)

    Rogers, Leslie A.

    2016-10-01

    The Kepler Mission, combined with ground based radial velocity (RV) follow-up, has revolutionized the observational constraints on sub-Neptune-size planet compositions. Kepler's unprecedentedly large and homogeneous samples of planets with both mass and radius constraints open the possibility of statistical studies of the underlying planet composition distribution. This presentation describes the application of hierarchical Bayesian models to constrain the underlying planet composition distribution from a sample of noisy mass-radius measurements. This approach represents a promising avenue toward a quantitative measurement of the amount of physical scatter in small planet compositions, the identification of planet sub-populations that may be tied to distinct formation pathways, and empirical constraints on the dominant compositional trends in the planet sample. Both the transit and radial velocity techniques are subject to selection effects, and approaches to mitigate the resulting biases will be addressed. In addition to distilling composition-distribution insights from the current sample of Kepler planets with RV masses, this framework may be used to optimize the target selection for future transiting planet RV follow-up surveys.

  20. Radial Velocity Eclipse Mapping of Exoplanets

    NASA Astrophysics Data System (ADS)

    Nikolov, Nikolay; Sainsbury-Martinez, Felix

    2015-07-01

    Planetary rotation rates and obliquities provide information regarding the history of planet formation, but have not yet been measured for evolved extrasolar planets. Here we investigate the theoretical and observational perspective of the Rossiter-McLaughlin effect during secondary eclipse (RMse) ingress and egress for transiting exoplanets. Near secondary eclipse, when the planet passes behind the parent star, the star sequentially obscures light from the approaching and receding parts of the rotating planetary surface. The temporal block of light emerging from the approaching (blueshifted) or receding (redshifted) parts of the planet causes a temporal distortion in the planet’s spectral line profiles resulting in an anomaly in the planet’s radial velocity curve. We demonstrate that the shape and the ratio of the ingress-to-egress radial velocity amplitudes depends on the planetary rotational rate, axial tilt, and impact factor (i.e., sky-projected planet spin-orbital alignment). In addition, line asymmetries originating from different layers in the atmosphere of the planet could provide information regarding zonal atmospheric winds and constraints on the hot spot shape for giant irradiated exoplanets. The effect is expected to be most-pronounced at near-infrared wavelengths, where the planet-to-star contrasts are large. We create synthetic near-infrared, high-dispersion spectroscopic data and demonstrate how the sky-projected spin axis orientation and equatorial velocity of the planet can be estimated. We conclude that the RMse effect could be a powerful method to measure exoplanet spins.