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1

Stability of radial swirl flows  

NASA Astrophysics Data System (ADS)

The energy gradient theory is used to examine the stability of radial swirl flows. It is found that the flow of free vortex is always stable, while the introduction of a radial flow will induce the flow to be unstable. It is also shown that the pure radial flow is stable. Thus, there is a flow angle between the pure circumferential flow and the pure radial flow at which the flow is most unstable. It is demonstrated that the magnitude of this flow angle is related to the Re number based on the radial flow rate, and it is near the pure circumferential flow. The result obtained in this study is useful for the design of vaneless diffusers of centrifugal compressors and pumps as well as other industrial devices.

Dou, H. S.; Khoo, B. C.

2012-11-01

2

Radial flow heat exchanger  

DOEpatents

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

Valenzuela, Javier (Hanover, NH)

2001-01-01

3

Radial flow pulse jet mixer  

DOEpatents

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.

VanOsdol, John G.

2013-06-25

4

Boiling Radial Flow in Fractures of Varying  

E-print Network

SGP-TR-166 Boiling Radial Flow in Fractures of Varying Wall Porosity Robb Allan Barnitt June 2000 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

Stanford University

5

Radial flow nuclear thermal rocket (RFNTR)  

DOEpatents

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.

Leyse, Carl F.

1995-11-07

6

Radial flow nuclear thermal rocket (RFNTR)  

DOEpatents

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.

Leyse, Carl F. (Idaho Falls, ID)

1995-01-01

7

Calculating the Flow Field in a Radial Turbine Scroll  

NASA Technical Reports Server (NTRS)

Set of two computer programs calculates flow field in radial turbine scroll. Programs represent improvement in analyzing flow in radial turbine scrolls and provide designer with tools for designing better scrolls. Programs written in FORTRAN IV.

Baskharone, E.; Abdallah, S.; Hamed, A.; Tabaoff, W.

1983-01-01

8

Radial Chromatography for the Separation of Nitroaniline Isomers  

ERIC Educational Resources Information Center

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…

Miller, Robert B.; Case, William S.

2011-01-01

9

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

ERIC Educational Resources Information Center

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…

Ondrus, Martin G.; And Others

1983-01-01

10

Measurement of anisotropic radial flow in relativistic heavy ion collisions  

E-print Network

We suggest the azimuthal distribution of mean transverse (radial) rapidity of the final state particles as a more direct measure of the transverse motion of the source than the standard azimuthal multiplicity distribution. Using a sample generated by the AMPT model with string melting, we demonstrate that the azimuthal amplitude of the suggested distribution characterizes the anisotropic radial flow, and coincides with the parameter of anisotropic radial rapidity extracted from a generalized blast-wave parametrization.

Lin Li; Na Li; Yuanfang Wu

2012-10-05

11

Oblique radial forearm reverse-flow flap.  

PubMed

A modifed design for the distally-based radial forearm flap is presented, in an oblique direction rather than longitudinally, based on the existence of skin laxity in the proximal forearm region. The skin paddle of the flap is designed in an oblique fashion pedicled on one of the proximal-row septocutaneous perforators, and elevated in the usual manner supplied by the distal radial artery. The oblique radial forearm flap thus created was successfully utilized for reconstruction of seven dorsal hand defects. Results showed that all the flaps could easily be transposed to the defect through a wide arc of rotation and all survived totally, with direct closure of the donor site in five cases, and significant reduction in size in the remaining two cases. It was concluded that the oblique design for the skin island of the reverse radial forearm flap could allow creation of a flap that has a smaller donor defect and yet presents a longer pedicle length, with a wider arc of rotation and better adaptation to a dorsal hand defect, than a conventional longitudinal-design radial forearm flap. PMID:12582958

Akyürek, Mustafa; Safak, Tunç; Keçik, Abdullah

2003-01-01

12

Zonal flows in stellarators in an ambient radial electric field  

SciTech Connect

The linear dynamics of zonal flows is addressed in stellarator geometry in the presence of an ambient (neoclassical) radial electric field. Global gyrokinetic particle-in-cell simulations are used to study the properties of the residual flow and its dependence on the plasma parameters and magnetic geometry. Properties of the zonal flow are compared in different magnetic geometries.

Mishchenko, Alexey; Kleiber, Ralf [Max-Planck-Institut fuer Plasmaphysik, EURATOM-Association, D-17491 Greifswald (Germany)

2012-07-15

13

Dynamics of a vortex pair in radial flow  

SciTech Connect

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

Bannikova, E. Yu., E-mail: bannikova@astron.kharkov.ua; Kontorovich, V. M. [National Academy of Sciences of Ukraine, Institute of Radio Astronomy (Ukraine)], E-mail: vkont@ira.kharkov.ua; Reznik, G. M. [Russian Academy of Sciences, Shirshov Institute of Oceanology (Russian Federation)], E-mail: greznik11@yahoo.com

2007-10-15

14

Radial plasma flow in a hot anode vacuum arc  

Microsoft Academic Search

The free, steady state, two-dimensional radial plasma flow initiated between a pair of disk-shaped electrodes of a hot anode vacuum arc was analyzed in the hydrodynamic approximation. Studies include the influence of the self-magnetic field on the plasma density, velocity, radial spreading of the arc current and potential distribution. The free plasma boundary was calculated by solving the equations for

I. I. Beilis; M. Keidar; R. L. Boxman; S. Goldsmith; J. Heberlein; E. Pfender

1999-01-01

15

A theory for radial jet reattachment flow  

E-print Network

TURBULENT FLOW R, = 8; Sigma = 10 ? 0. 05 tll t ttt ? 0 10 I 0 0 -0. 15 C e tll oo 020 -0. 25 0 zle Exit Angle, 8, ? 20 10 20 30 02 05 o" oo ohio" oeooxo Nozzle Exit Distance, Delta Noz ? 30 y' ? 10 / 0 Figure 3. Nozzle exit angle... Nozzle Exit Distance, Delta Figure 4. Nozzle exit angle curves showing the effect of nozzle exit distance on coefficient of pressure for lareinar flow. TURBULENT FLOW R, = 8; Sigma = 10 25 s e 20 'a o 15 E 10 a e CL Nozzle Exit Angle, 6...

Hadden, Lynne Loise

1987-01-01

16

Acceleration and ejection of interacting ring vortices by radial flow  

NASA Astrophysics Data System (ADS)

Exact solution of two-dimensional hydrodynamic equations for symmetrical configuration of four point vortices in the presence of radial flow is found. This solution describes the dynamics of a dipole toroidal vortex (consisting of two counter-rotating vortex rings) in such a flow. It is shown that in a convergent flow the ring vortices are compressed and ejected with acceleration along the symmetry axes of the system. Possible application to the problem of jets formation in active galaxy nuclei is considered.

Bannikova, E. Yu.; Kontorovich, V. M.

2009-05-01

17

Primary instability of a Taylor-Couette flow with a radial stratification and radial buoyancy  

NASA Astrophysics Data System (ADS)

We consider the primary instability onset of a Taylor-Couette flow with a radial stratification and radial volumic force. Our system corresponds to a simplified geophysical model that takes into account the effect of the buoyancy opposed to the centrifugal force. Three parameters of the physical problem, which correspond to the buoyancy, the diffusivity, and the rotational velocity, are considered to describe the onset of the primary instability. Using an efficient numerical method, we compute the threshold value of the Taylor number, which depends on the Froude and Schmidt numbers, and describe the most unstable mode provided by the linear analysis.

Jenny, Mathieu; Nsom, Blaise

2007-10-01

18

Multiphase flow modeling in centrifugal partition chromatography.  

PubMed

The separation efficiency in Centrifugal Partition Chromatography (CPC) depends on selection of a suitable biphasic solvent system (distribution ratio, selectivity factor, sample solubility) and is influenced by hydrodynamics in the chambers. Especially the stationary phase retention, the interfacial area for mass transfer and the flow pattern (backmixing) are important parameters. Their relationship with physical properties, operating parameters and chamber geometry is not completely understood and predictions are hardly possible. Experimental flow visualization is expensive and two-dimensional only. Therefore we simulated the flow pattern using a volume-of-fluid (VOF) method, which was implemented in OpenFOAM®. For the three-dimensional simulation of a rotating FCPC®-chamber, gravitational centrifugal and Coriolis forces were added to the conservation equation. For experimental validation the flow pattern of different solvent systems was visualized with an optical measurement system. The amount of mobile phase in a chamber was calculated from gray scale values of videos recorded by an image processing routine in ImageJ®. To visualize the flow of the stationary phase polyethylene particles were used to perform a qualitative particle image velocimetry (PIV) analysis. We found a good agreement between flow patterns and velocity profiles of experiments and simulations. By using the model we found that increasing the chamber depth leads to higher specific interfacial area. Additionally a circular flow in the stationary phase was identified that lowers the interfacial area because it pushes the jet of mobile phase to the chamber wall. The Coriolis force alone gives the impulse for this behavior. As a result the model is easier to handle than experiments and allows 3D prediction of hydrodynamics in the chamber. Additionally it can be used for optimizing geometry and operating parameters for given physical properties of solvent systems. PMID:21324465

Adelmann, S; Schwienheer, C; Schembecker, G

2011-09-01

19

Radial Plasma Flow Switch on GIT-12 Generator  

SciTech Connect

The preliminary experiments were performed on wire array implosion driven by a radial plasma flow switch on the GIT-12 generator operating in a microsecond mode. Imploding gas puff z-pinch plasma was used to provide fast switching of the current to an aluminum wire array. The experimental results are presented in the paper.

Chaikovsky, S.A.; Kokshenev, V.A.; Rousskikh, A.G.; Shishlov, A.V.; Fedunin, A.V.; Labetsky, A.Yu.; Kurmaev, N.E.; Fursov, F.I. [Institute of High Current Electronics, 2/3 Akademichesky Ave., Tomsk, 634055 (Russian Federation)

2006-01-05

20

Analysis and performance of radial flow rotary dessicant dehumidifiers  

SciTech Connect

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

Elsayed, M.M.; Chamkha, A.J. [Kuwait Univ., Safat (Kuwait). Mechanical and Industrial Engineering Dept.

1997-02-01

21

Radial accretion flows on static spherically symmetric black holes  

E-print Network

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

Chaverra, Eliana

2015-01-01

22

MECHANICS OF PASTE FLOW IN RADIAL SCREEN EXTRUDERS  

Microsoft Academic Search

High solids volume particle-liquid mixtures, sometimes called pastes, often exhibit apparent yield stress behaviour and once formed, e.g. by extrusion, will retain their shape. Radial screen extruders have been developed for high flow rate, low mean pressure extrusion through multiple small diameter dies (< ~1.5 mm). The principles underlying the design and operation of these extruders are not well understood

P. J. Martin; D. I. Wilson

23

A Method to Estimate the Accuracy of Radial Flow—Based Permeability Measuring Devices  

Microsoft Academic Search

Radial flow experiment is often used to measure the permeability of fibrous porous media by the composites processing community. However, very little work has been done to calibrate the radial flow set-up with media of known permeability. This article presents a new method for calibrating the permeability measuring set-ups based on radial flows. A reference medium in the form of

Hua Tan; Krishna M. Pillai

2009-01-01

24

Radial Flow of Dust Particles in Accretion Disks  

E-print Network

We study the radial migration of dust particles in accreting protostellar disks analogous to the primordial solar nebula. This study takes account of the two dimensional (radial and normal) structure of the disk gas, including the effects of the variation in the gas velocity as a function of distance from the midplane. It is shown that the dust component of disks accretes slower than the gas component. At high altitude from the disk midplane, the gas rotates faster than particles because of the inward pressure gradient force, and its drag force causes particles to move outward in the radial direction. Viscous torque induces the gas within a scale height from the disk midplane to flow outward, carrying small (size 1 mm at 10 AU) move inward. When the particles' radial velocities are averaged over the entire vertical direction, particles have a net inward flux. At large distances from the central star, particles migrate inward with a velocity much faster than the gas accretion velocity. However, their inward velocity is reduced below that of the gas in the inner regions of the disk. The rate of velocity decrease is a function of the particles' size. While larger particles retain fast accretion velocity until they approach closer to the star, 10 micron particles have slower velocity than the gas in the most part of the disk (r gas disks, resulting in the increase in the dust-gas ratio during the gas accretion phase.

Taku Takeuchi; D. N. C. Lin

2002-08-29

25

Submicrometer particles and slip flow in liquid chromatography.  

PubMed

Smaller particles have progressively led to higher efficiency in liquid chromatography, particularly for proteins, due to smaller diffusion distances. Particle diameter has recently entered the submicrometer region, with the back-pressure requirements alleviated by slip flow. PMID:25646567

Rogers, Benjamin A; Wu, Zhen; Wei, Bingchuan; Zhang, Ximo; Cao, Xiang; Alabi, Oyeleye; Wirth, Mary J

2015-03-01

26

Moving bed radial flow reactor for high gas flow  

Microsoft Academic Search

This patent describes an apparatus for contacting a bed of particulate material with a radius gas flow comprising a pair of vertically and horizontally elongated partitions, in a spaced apart relationship, coextensive with the horizontal length of the partitions, a top bed closure at least partially defining the top of the particle retention space. This patent describes a improvement in

W. J. Koves; R. L. Throndson

1992-01-01

27

A visual study of radial inward choked flow of liquid nitrogen  

NASA Technical Reports Server (NTRS)

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

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

1973-01-01

28

Onset of radial flow in p +p collisions  

NASA Astrophysics Data System (ADS)

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 or as clean as in heavy-ion collisions because of the low multiplicity and large fluctuation in p +p collisions. The 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 the BNL Relativistic Heavy Ion Collider (RHIC) to the CERN Large Hadron Collider (LHC) using TBW and have found no appreciable radial flow in p +p collisions below ?{s }=900 GeV. At the LHC higher energy of 7 TeV in p +p collisions, the radial flow velocity achieves an average value of =0.320 ±0.005 . This flow velocity is comparable to that in peripheral (40-60%) Au +Au collisions at the RHIC. Breaking of the identified particle spectra mT scaling was also observed at the LHC from a model-independent test.

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

2015-02-01

29

Radial accretion flows on static spherically symmetric black holes  

E-print Network

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

Eliana Chaverra; Olivier Sarbach

2015-01-07

30

Moving bed radial flow reactor for high gas flow  

SciTech Connect

This patent describes an apparatus for contacting a bed of particulate material with a radius gas flow comprising a pair of vertically and horizontally elongated partitions, in a spaced apart relationship, coextensive with the horizontal length of the partitions, a top bed closure at least partially defining the top of the particle retention space. This patent describes a improvement in the top bed closure inlet opening which extends horizontally over the transverse length of the particle retention space opening.

Koves, W.J.; Throndson, R.L.

1992-07-14

31

Linear and radial flow targets for characterizing downhole flow in perforations  

SciTech Connect

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.

Deo, M. (Stanford Univ., CA (USA)); Tariq, S.M. (Schlumberger Well Services, Houston, TX (USA)); Halleck, P.M. (Terra Tek, Inc., Salt Lake City, UT (USA))

1989-08-01

32

Experimental and numerical study of radial flow and its contribution to wake development of a HAWT  

Microsoft Academic Search

The scope of this work was to investigate radial flow component for a Horizontal Axis Wind Turbine in axial flow conditions and to assess its impact on the turbine operation. This was done by means of Particle Image Velocimetry and numerical simulation with a 3D unsteady potential-flow panel model. A direct comparison between the numerical and experimental radial velocity results

D. Micallef; B. Akay; T. Sant; C. J. Simao Ferreira; G. J. W. Van Bussel

2011-01-01

33

Boiling radial flow in fractures of varying wall porosity  

SciTech Connect

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.

Barnitt, Robb Allan

2000-06-01

34

Standard Flow Liquid Chromatography for Shotgun Proteomics in Bioenergy Research  

PubMed Central

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

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

35

An investigation of radial tracer flow in naturally fractured reservoirs  

SciTech Connect

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.

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

1991-01-01

36

Instability of an inviscid flow between rotating porous cylinders with radial flow to three-dimensional perturbations  

E-print Network

We study the stability of two-dimensional inviscid flows in an annulus between two permeable cylinders with respect to three-dimensional perturbations. The basic flow is irrotational, and both radial and azimuthal components of the velocity are non-zero. The direction of the radial flow can be from the inner cylinder to the outer one (the diverging flow) or from the outer cylinder to the inner one (the converging flow). It had been shown earlier in \\citet{IM2013a} that, independent of the direction of the radial flow, the basic flow can be unstable to small two-dimensional perturbations. In the present paper, we prove first that purely radial flow is stable and that flows with both radial and azimuthal components are always stable to axisymmetric perturbations. Then we show that both the diverging and converging flows are unstable with respect to non-axisymmetric three-dimensional perturbations provided that the ratio of the azimuthal component of the velocity to the radial one is sufficiently large. Neutral curves in the space of parameters of the problem are computed and it is demonstrated that for any ratio of the radii of the cylinders, the most unstable modes (corresponding to the smallest ratio of the azimuthal velocity to the radial one) are the two-dimensional ones.

Konstantin Ilin; Andrey Morgulis

2015-03-16

37

Chromatography.  

ERIC Educational Resources Information Center

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)

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

38

Radial Gas Flows in Colliding Galaxies: Connecting Simulations and Observations  

E-print Network

(abridged) We investigate the detailed response of gas to the formation of transient and long-lived dynamical structures induced in the early stages of a disk-disk collision, and identify observational signatures of radial gas inflow through a detailed examination of the collision simulation of an equal mass bulge dominated galaxy. Stars respond to the tidal interaction by forming both transient arms and long lived m=2 bars, but the gas response is more transient, flowing directly toward the central regions within about 10^8 years after the initial collision. The rate of inflow declines when more than half of the total gas supply reaches the inner few kpc, where the gas forms a dense nuclear ring inside the stellar bar. The average gas inflow rate to the central 1.8 kpc is \\~7 Msun/yr with a peak rate of 17 Msun/yr. The evolution of gas in a bulgeless progenitor galaxy is also discussed, and a possible link to the ``chain galaxy'' population observed at high redshifts is inferred. The evolution of the structural parameters (the asymmetry and concentration) of both stars and gas are studied in detail. Further, a new structural parameter (the compactness parameter K) that traces the evolution of the size scale of the gas relative to the stellar disk is introduced. Non-circular gas kinematics driven by the perturbation of the non-axisymmetric structure can produce distinct emission features in the "forbidden velocity quadrants'' of the position-velocity diagram (PVD). The dynamical mass calculated using the rotation curve derived from fitting the emission envelope of the PVD can determine the true mass to within 20% to 40%. The evolution of the molecular fraction $M_H2/M_(H2 + HI) and the compactness (K) are potential tracers to quantitatively assign the age of the interaction.

Daisuke Iono; Min S. Yun; J. Christopher Mihos

2004-07-29

39

Hhdrodenitrogenation catalysis studied by reversed-flow gas chromatography  

Microsoft Academic Search

Many important parameters of surface catalysed reactions can be determined simultaneously, under nonsteady state conditions using Reversed-Flow Gas Chromatography. A simple, slightly modified gas chromatograph is required. The distorted diffusion bands, obtained experimentally for reactant and product(s), can be analysed mathematically, using simple PC programs, to give the pre-exponential factors and the exponential coefficients of a function consisting of the

A. Niotis; N. A. Katsanos

1992-01-01

40

Computational investigations of axial and radial flow compressor aeromechanics  

NASA Astrophysics Data System (ADS)

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

Ramakrishnan, Kishore

41

Buoyancy-driven flow reversal phenomena in radially rotating serpentine ducts  

SciTech Connect

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

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

2000-02-01

42

Simulation of the Flow Control of Radial Piston Pump Based on Simulink  

Microsoft Academic Search

The flow control of radial piston is widely used in speed, position servo system. In this paper the mathematic model of the test radial piston pump is established and the simulation diagram is established in the simulink of MATLAB. Then the response curves of the system are achieved. The performance of the system is improved after adding the fuzzy-PID controller.

Qiu Xinguo; Chen Libin; Jiang Wei

2010-01-01

43

One-dimensional analysis of plane and radial thin film flows including solid-body rotation  

NASA Technical Reports Server (NTRS)

The flow of a thin liquid film with a free surface along a horizontal plate which emanates from a pressurized vessel is examined by integrating the equations of motion across the thin liquid layer and discretizing the integrated equations using finite difference techniques. The effects of 0-g and solid-body rotation will be discussed. The two cases of interest are plane flow and radial flow. In plane flow, the liquid is considered to be flowing along a channel with no change in the width of the channel, whereas in radial flow the liquid spreads out radially over a disk, so that the area changes along the radius. It is desired to determine the height of the liquid film at any location along the plate of disk, so that the heat transfer from the plate or disk can be found. The possibility that the flow could encounter a hydraulic jump is accounted for.

Thomas, S.; Hankey, W.; Faghri, A.; Swanson, T.

1989-01-01

44

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

NASA Astrophysics Data System (ADS)

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.

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

2014-11-01

45

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

NASA Technical Reports Server (NTRS)

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.

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

1977-01-01

46

Flow field characteristics of a radial jet reattaching on a flat plate  

E-print Network

from Flow Visualization and Pressure Distributions. 103 2. Geometric Uncertainties. 121 3. Nozzle Exit Velocity Uncertainties 121 ix LI ST OF FI CURES Figure Flow Pattern During Radial Jet Reattachment Experimental Test Apparatus Disassembled... were measured. The experiments were performed using a number of nozzle exit angles, distances from surface to nozzle exit, and jet flow rates. Flow visualization was also carried out in an effort to confirm the expected flow patterns. J. D. Mac...

Carbone, Janique Sylvia

1988-01-01

47

Longitudinal diffusion in size-exclusion chromatography: a stop-flow size-exclusion chromatography study.  

PubMed

Band broadening in size-exclusion chromatography (SEC) has an adverse effect upon calculated molecular mass averages, distributions, and dilute solution data generated using single- and multi-detector systems. In the past, the longitudinal diffusion contribution to band broadening in SEC has been considered negligible. This assumption has been investigated by using a stop-flow methodology (SF-SEC) that maximizes the potential for longitudinal diffusion while minimizing that for mass transfer. Under the given experimental conditions, the effects of B-term band broadening were manifest only below 30 KDa, irrespective of chemical functionality or molecular mass polydispersity. This type of broadening was found to be flow rate-independent for a representative high molecular mass polymer. PMID:11695865

Striegel, A M

2001-10-12

48

Liquid chromatography/Fourier transform IR spectrometry interface flow cell  

DOEpatents

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.

Johnson, Charles C. (Fairfield, OH); Taylor, Larry T. (Blacksburg, VA)

1986-01-01

49

Liquid chromatography/Fourier transform IR spectrometry interface flow cell  

DOEpatents

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.

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

1985-01-04

50

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

51

A flow study in radial inflow turbine scroll-nozzle assembly  

NASA Technical Reports Server (NTRS)

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.

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

1978-01-01

52

Instability of an inviscid flow between rotating porous cylinders with radial flow to three-dimensional perturbations  

E-print Network

We study the stability of two-dimensional flows in an annulus between two permeable cylinders with respect to three-dimensional perturbations. The basic flow is irrotational, and both radial and azimuthal components of the velocity are non-zero. The direction of the radial flow can be from the inner cylinder to the outer one (the diverging flow) or from the outer cylinder to the inner one (the converging flow). It is shown that, independent of the direction of the radial flow, the basic flow is unstable to small two-dimensional perturbations provided that the ratio of the azimuthal component of the velocity to the radial one is sufficiently large. The instability is oscillatory, and the unstable modes represent travelling azimuthal waves. Neutral curves in the space of parameters of the problem are computed. It turns out that for any geometry of the problem, the most unstable modes (corresponding to the smallest ratio of the azimuthal velocity to the radial one) are two-dimensional ones studied earlier in \\ci...

Ilin, Konstantin

2015-01-01

53

[Venous flow reversal and the pedicled radial island flap (anatomic study)].  

PubMed

In the distally pedicled radial island flap a reverse venous flow was observed. In 20 cadaver extremities the veins of the forearms were perfused, dissected and also island flaps elevated. The three venous systems are described as to number, localization and shape of the flaps with an explanation of the venous flow. PMID:3623267

Piza-Katzer, H; Weinstabl, R

1987-07-01

54

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

SciTech Connect

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.

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

2000-04-01

55

Chromatography  

NSDL National Science Digital Library

This site provides fundamental background information about chromatography, including plate theory, rate theory, the mechanisms of separations, and qualitative and quantitative aspects of chromatography. The format is a series of PowerPoint-like presentations available in PDF format.

Hardy, James K.

56

Chromatography  

MedlinePLUS

... high pressure liquid, or ion exchange chromatography. In general, chromatography takes advantage of the differences in the chemicals you want to separate, such as their size, electric charge, or ability to stick to (bind) to ...

57

Three-dimensional flow field measurements in a radial inflow turbine scroll using LDV  

NASA Technical Reports Server (NTRS)

The results of an experimental study of the three-dimensional flow field in a radial inflow turbine scroll are presented. A two-color LDV system was used in the measurement of three orthogonal velocity components at 758 points located throughout the scroll and the unvaned portion of the nozzle. The cold flow experimental results are presented for through-flow velocity contours and the cross velocity vectors.

Malak, M. F.; Hamed, A.; Tabakoff, W.

1986-01-01

58

Radial flow towards well in leaky unconfined aquifer  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

59

Flow behavior in inlet guide vanes of radial turbines  

NASA Technical Reports Server (NTRS)

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

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

1975-01-01

60

Possible Suppression of MRI by Rapid Radial Flow  

NASA Astrophysics Data System (ADS)

By investigating the magnetorotational instability (MRI) in a region of rapidly varying accretion-disk thickness, e.g., in the ISCO region, we find a limit to the applicability of a recent finding by Balbus (2012) that the MRI is present also in the region of Rayleigh-unstable flow.

Abramowicz, M. A.; Horák, J.; Klu?niak, W.

2013-06-01

61

Three-dimensional flow measurements in a vaneless radial turbine scroll  

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

62

Occurrence of turbulent flow conditions in supercritical fluid chromatography.  

PubMed

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 ?m 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 ?m. By calculating the Darcy friction factor, which can be plotted versus the Reynolds number in a so-called Moody chart, typically used in fluid dynamics, higher values are found for stainless steel than PEEK tubing, in agreement with their expected higher surface roughness. As a result turbulent effects are more pronounced when using stainless steel tubing. The higher than expected extra-column pressure drop limits the kinetic performance of supercritical fluid chromatography and complicates the optimization of tubing ID, which is based on a trade-off between extra-column band broadening and pressure drop. One of the most important practical consequences is the non-linear increase in extra-column pressure drop over the tubing downstream of the column which leads to an unexpected increase in average column pressure and mobile phase density, and thus decrease in retention. For close eluting components with a significantly different dependence of retention on density, the selectivity can significantly be affected by this increase in average pressure. In addition, the occurrence of turbulent flow is also observed in the detector cell and connection tubing. This results in a noise-increase by a factor of four when going from laminar to turbulent flow (e.g. going from 0.5 to 2.5 ml/min for neat CO2). PMID:25145564

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

2014-09-26

63

Use of a mechanical leech in a reverse-flow radial forearm flap: case report.  

PubMed

The reverse-flow radial forearm flap provides excellent coverage for distal upper-limb defects. It is simply raised and does not require microsurgical skills. However, since its vascular pedicle is reversed, its venous outflow can be significantly diminished because of the venous valves. The authors present the case of a 16-year-old patient with a sagittal amputation of the radial aspect of the right thumb, who manifested at the time of surgery marked venous engorgement of a reverse-flow radial forearm flap. This was successfully relieved by the placement of a mechanical leech consisting of a Silastic rubber catheter--of the kind used to gain central vascular access in newborns--introduced in the lumen of the reversed vein at the extremity of the flap. This permitted intermittent evacuation of blood from the flap postoperatively, contributing to the success of this procedure. The technique used is detailed and pertinent literature is reviewed. PMID:11499467

La Scala, G C; Carroll, S M; Forrest, C R; Zuker, R M

2001-07-01

64

Effects of Skeletonized versus Pedicled Radial Artery on Postoperative Graft Patency and Flow  

PubMed Central

Background Radial artery (RA) was the second arterial graft introduced in clinical practice for myocardial revascularization. The skeletonization technique of the left internal thoracic artery (LITA) may actually change the graft's flow capacity with potential advantages. This leads to the assumption that the behavior of the RA, as a coronary graft, is similar to that of the LITA, when skeletonized. Objective This study evaluated 'free' aortic-coronary radial artery (RA) grafts, whether skeletonized or with adjacent tissues. Methods A prospective randomized study comparing 40 patients distributed into two groups was conducted. In group I, we used skeletonized radial arteries (20 patients), and in group II, we used radial arteries with adjacent tissues (20 patients). After the surgical procedure, patients underwent flow velocity measurements. Results The main surgical variables were: RA internal diameter, RA length, and free blood flow in the radial artery. The mean RA graft diameters as calculated using quantitative angiography in the immediate postoperative period were similar, as well as the flow velocity measurement variables. On the other hand, coronary cineangiography showed the presence of occlusion in one RA graft and stenosis in five RA grafts in GII, while GI presented stenosis in only one RA graft (p = 0.045). Conclusion These results show that the morphological and pathological features, as well as the hemodynamic performance of the free radial artery grafts, whether prepared in a skeletonized manner or with adjacent tissues, are similar. However, a larger number of non-obstructive lesions may be observed when RA is prepared with adjacent tissues. PMID:24918911

Bonini, Rômulo C. Arnal; Staico, Rodolfo; Issa, Mario; Arnoni, Antoninho Sanfins; Chaccur, Paulo; Abdulmassih, Camilo; Dinkhuysen, Jarbas Jackson; Paulista, Paulo Paredes; de Souza, Luiz Carlos Bento; Moreira, Luiz Felipe P.

2014-01-01

65

A finite element viscous flow analysis in a radial turbine scroll  

E-print Network

CHAPTER I INTRODUCTION In many power system applications involving low specific-speed gas turbines, radial inflow turbines(Figure 1) can offer many advantages over the axial ? flow type. These include a high pressure ratio, relative insensitivity... accurate in continuous-flow gas turbine apllications under a sufflciently low Reynolds number mode of operation. The assumption, however, becomes less accurate for scrolls designed as tui'bocharger components in reciprocating entpne applications...

Hill, Donald Lee

1987-01-01

66

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

NASA Astrophysics Data System (ADS)

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

Briesemeister, Alexis R.

67

Chromatography  

NSDL National Science Digital Library

This lab activity from the Biotechnology Alliance for Suncoast Biology Educators covers background information on the basic types of chromatography and has the student separate pigments extracted from pens and plant leaves using paper chromatography. The lesson includes the materials needed and the demonstration procedures.

Keirle, Matt

68

L. D. V. measurements and investigation of flow field through radial turbine guide vanes  

SciTech Connect

The results of Laser Doppler Velocimeter (LDV) measurements and investigation of detailed flow field through radial inflow turbine guide vanes are presented. The flow velocities were measured at five stations upstream, inside and downstream of the guide vanes for two different mass flow rates. Data was collected at 600 points in total. A three-component LDV system was used for the velocity measurements. The results are presented as contour plots of mean velocities, flow angles, and turbulent stresses. Significant end-wall cross flows were observed inside the blade passages close to the trailing edges. However, these cross flows are different from the ones in axial turbines because of the counter effects of the radial pressure gradient, the blade shape, and the high negative incidence angle. The flow field through the blade passages was found to be strongly influenced by the scroll geometry. The lack of periodicity between flow channels and asymmetry with respect to the two end walls were attributed to this upstream influence. In addition to the experimental investigation, an analytical study of the flow field through the guide vanes of the turbine was performed. Agreement between the experimental and numerical results is satisfactory.

Eroglu, H.

1988-01-01

69

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

SciTech Connect

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.

Nesreddine, H.; Nguyen, C.T.; Vo-Ngoc, D. [Univ. de Moncton, New Brunswick (Canada). School of Engineering

1995-05-01

70

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

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

71

Chromatography  

NSDL National Science Digital Library

In this activity, explore chromatography and the various colors that make up the ink in markers. Use this activity to investigate cohesion and adhesion. The online version of this activity is set up so that learners solve a mystery.

2014-04-25

72

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

PubMed

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

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

2013-11-01

73

Radial Spreading of Drift-Wave-Zonal-Flow Turbulence via Soliton Formation  

SciTech Connect

The self-consistent spatiotemporal evolution of a drift-wave (DW) radial envelope and a zonal-flow (ZF) amplitude is investigated in a slab model. The stationary solution of the coupled partial differential equations in a simple limit yields the formation of DW-ZF soliton structures, which propagate radially with speed depending on the envelope peak amplitude. Additional interesting physics, e.g., the generation, destruction, collision, and reflection of solitons, as well as turbulence bursting can also be observed due to the effects of linear growth or damping, dissipation, equilibrium nonuniformities and soliton dynamics. The propagation of soliton causes significant radial spreading of DW turbulence and therefore can affect transport scaling with the system size by broadening of the turbulent region. The correspondence of the present analysis with the description of DW-ZF interactions in toroidal geometry is also discussed.

Guo Zehua [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States); Chen Liu [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States); Institute for Fusion Theory and Simulation, Zhe Jiang University, Hangzhou, Zhejiang (China); Zonca, Fulvio [Associazione EURATOM-ENEA sulla Fusione, C.P. 65-00044 Frascati (Italy)

2009-07-31

74

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

PubMed

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. PMID:22900478

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

2013-01-01

75

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

NASA Astrophysics Data System (ADS)

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.

Gin, Craig; Daripa, Prabir

2015-01-01

76

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

NASA Astrophysics Data System (ADS)

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

Kalaydzhyan, Tigran; Shuryak, Edward

2014-11-01

77

Cutaneous anthrax of the hand and its reconstruction with a reverse-flow radial forearm flap.  

PubMed

Bacillus anthracis infection can lead to necrosis in tissues and may manifest as a fatal disease in human beings. The authors present a patient with a large area of skin necrosis on the dorsum of the hand that was reconstructed with a reverse flow-through radial forearm flap, and they discuss the relevant literature. To the authors' knowledge, this is the first published report of such extensive necrosis resulting from anthrax limited to the extensor retinaculum of the hand. PMID:12142604

Coban, Y Kenan; Balik, Ozgul; Boran, Cetin

2002-07-01

78

Chromatography  

NSDL National Science Digital Library

The North Carolina Community College System BioNetwork's interactive eLearning tools (IETs) are reusable chunks of training that can be deployed in a variety of courses or training programs. IETs are designed to enhance, not replace hands-on training. Learners are able to enter a hands-on lab experience better prepared and more confident. This particular IET delves into chromatography including the basics, the three types (affinity, ion exchange, size exclusion), and the parts and functions associated with chromatography.

79

Laser velocimeter measurements in shrouded and unshrouded radial flow pump impellers  

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

80

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

SciTech Connect

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

Farkas, T.; Sepaniak, M.J.; Guiochon, G. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry] [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry; [Oak Ridge National Lab., TN (United States). Div. of Chemical and Analytical Sciences

1997-08-01

81

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

NASA Technical Reports Server (NTRS)

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

Heidmann, James D.; Beach, Timothy A.

1990-01-01

82

Three dimensional LDV flow measurements and theoretical investigation in a radial inflow turbine scroll  

NASA Technical Reports Server (NTRS)

A two-color LDV system was used in the measurement of three orthogonal velocity components at 758 points located throughout the scroll and the unvaned portion of the nozzle of a radial inflow turbine scroll. The cold flow experimental results are presented for the velocity field at the scroll tongue. In addition, a total pressure loss of 3.5 percent for the scroll is revealed from the velocity measurements combined with the static pressure readings. Moreover, the measurement of the three normal stresses of the turbulence has showed that the flow is anisotropic. Furthermore, the mean velocity components are compared with a numerical solution of the potential flow field using the finite element technique. The theoretical prediction of the exit flow angle variation agrees well with the experimental results. This variation leads to a higher scroll pattern factor which can be avoided by controlling the scroll cross sectional area distribution.

Malak, Malak Fouad; Hamed, Awatef; Tabakoff, Widen

1990-01-01

83

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

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

84

Chromatography  

NSDL National Science Digital Library

In this activity, by the Concord Consortium's Molecular Literacy project, students "learn about the phases of molecular separation, and then experiment with paper and ion chromatography." The activity itself is a java-based interactive resource built upon the free, open source Molecular Workbench software. In addition, visitors will find an overview of the activity, assessments, and concepts and their correlation to AAAS and NSES standards.

85

Chromatography  

NSDL National Science Digital Library

In this chemistry activity, learners will separate a mixture of FD&C dyes (colors certified and allowed by the US for the Food, Pharmaceutical, Cosmetics & Personal Care industry) to practice chromatography, a separation technique for mixtures. Learners will record their observations on a data table and note trends. This resource includes questions for learners and instructions for preparing the colors from M&Ms, Orange Kool-Aid, and food coloring.

The Science House

2014-01-28

86

A radial flow hollow fiber bioreactor for the large-scale culture of mammalian cells.  

PubMed

A radial flow hollow fiber bioreactor has been developed that maximizes the utilization of fiber surface for cell growth while eliminating nutrient and metabolic gradients inherent in conventional hollow fiber cartridges. The reactor consists of a central flow distributor tube surrounded by an annular bed of hollow fibers. The central flow distributor tube ensures an axially uniform radial convective flow of nutrients across the fiber bed. Cells attach and proliferate on the outer surface of the fibers. The fibers are pretreated with polylysine to facilitate cell attachment and long-term maintenance of tissuelike densities of cell mass. A mixture of air and CO(2) is fed through the tube side of the hollow fibers, ensuring direct oxygenation of the cells and maintenance of pH. Spent medium diffuses across the cell layer into the tube side of the fibers and is convected away along with the spent gas stream. The bioreactor was run as a recycle reactor to permit maximum utilization of nutrient medium. A bioreactor with a membrane surface area of 1150 cm(2) was developed and H1 cells were grown to a density of 7.3 x 10(6) cells/cm(2). PMID:18555333

Tharakan, J P; Chau, P C

1986-03-01

87

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

SciTech Connect

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

Sanchez, R. [Fusion Energy Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-8071 (United States); Newman, D. E. [Department of Physics, University of Alaska, Fairbanks, Alaska 99775-5920 (United States); Leboeuf, J.-N. [JNL Scientific, Inc., Casa Grande, Arizona 85294-9695 (United States); Carreras, B. A. [BACV Solutions, Inc., Oak Ridge, Tennessee 37830-8222 (United States); Decyk, V. K. [UCLA, Los Angeles, California 90095-1547 (United States)

2009-05-15

88

Isospin dependence of nucleon emission and radial flow in heavy-ion collisions induced by high energy radioactive beams  

E-print Network

Using an isospin- and momentum-dependent transport model we study the emission of free nucleons and the nuclear radial flow in central heavy-ion collisions induced by high energy radioactive beams. The midrapidity neutron/proton ratio and its transverse momentum dependence are found very sensitive to the high density behavior of nuclear symmetry energy. The nuclear radial flow, however, depends only weakly on the symmetry energy.

Bao-An Li; Gao-Chan Yong; Wei Zuo

2004-12-20

89

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

NASA Technical Reports Server (NTRS)

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.

Wu, Chung-Hua; Wolfenstein, Lincoln

1950-01-01

90

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

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

91

A generalized radial-flow model for hydraulic tests in fractured rock  

NASA Astrophysics Data System (ADS)

Models commonly used for the analysis of hydraulic test data are generalized by regarding the dimension of the flow to be a parameter which is not necessarily integral and which must be determined empirically. Mathematical solutions for this generalized radial flow model are derived for the standard test conditions: constant rate, constant head, and slug tests. Solutions for the less common, sinusoidal test are contained within the general solutions given. Well bore storage and skin are included and the extension to dual-porosity media outlined. The model is presented as a model of fractured media, for which it is most likely to find application because of the problem of choosing the appropriate flow dimension.

Barker, J. A.

1988-10-01

92

Solution of particulated viscous flow over a two dimensional cylinder and in a radial inflow turbine  

NASA Astrophysics Data System (ADS)

Particle trajectories, particle fluid interaction, and erosion were studied for different solid particle sizes. The vicosity of the carrier fluid was into account and particle trajectories in viscous and inviscid fluid were systematically compared. Experiments carried out on particulated viscous flow over a two dimensional cylinder demonstrates the effect of the particles on such important flow properties as fluid steamline pattern, coefficient of drag and recirculation zone. The important effects of the solid particles on the fluid streamline pattern in a blade channel of a radial inflow turbine and a mixed flow turbine are evaluated. Results demonstrate the difference in particle trajectories, and impact locations between vicous and inviscid solutions, which would affect erosion prediction in turbomachinery. Statistical methods are used in combination with three dimensional particle trajectory calculations, the basic experimental erosion data and particle rebound characteristics, to predict erosion pattern in the turbine rotor blades.

Vittal, B. V. R.

93

Granular circulation in a cylindrical pan: simulations of reversing radial and tangential flows.  

PubMed

Granular flows due to simultaneous vertical and horizontal excitations of a flat-bottomed cylindrical pan are investigated using event-driven molecular dynamics simulations. In agreement with recent experimental results, we observe a transition from a solidlike state to a fluidized state in which circulatory flow occurs simultaneously in the radial and tangential directions. By going beyond the range of conditions explored experimentally, we find that each of these circulations reverses its direction as a function of the control parameters of the motion. We numerically evaluate the dynamical phase diagram for this system and show, using a simple model, that the solid-fluid transition can be understood in terms of a critical value of the radial acceleration of the pan bottom and that the circulation reversals are controlled by the phase shift relating the horizontal and vertical components of the vibrations. We also discuss the crucial role played by the geometry of the boundary conditions and point out a relationship of the circulation observed here and the flows generated in vibratory conveyors. PMID:17930031

Baran, Oleh; Drozd, John J; Martinuzzi, Robert J; Poole, Peter H

2007-08-01

94

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

SciTech Connect

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

Jetzabeth Ramirez-Sabag; Fernando Samaniego V.

1992-01-01

95

On the origin of the radial flow in low energy heavy ion reactions  

E-print Network

The average transverse energy of nucleons and intermediate mass fragments observed in the heavy ion reaction Xe(50A MeV)+Sn shows the same linear increase as a function of their mass as observed in heavy ion collisions up to the highest ene rgies available today and fits well into the systematics. At higher energies this observation has been interpreted as a sign of a strong radial flow in an otherwise thermalized system. Investigating the reaction with Quantum Molecular dynamics simulations we find in between 50A MeV and 200A MeV a change in the reaction mechanism. At 50A MeV the apparent radial flow is merely caused by an in-plane flow and Coulomb repulsion. The average transverse fragment energy does not change in the course of the reaction and is equal to the initial fragment energy due to the Fermi motion. At 200A MeV, there are two kinds of fragments: those formed from spectator matte r and those from the center of the reaction. There the transverse energy is caused by the pr essure from the compressed nuclear matter. In both cases we observe a binary event stru cture, even in central collisions. This demonstrates as well the non thermal character of the reaction. The actual process which leads to multifragmentation is rather complex and is discussed in detail.

R. Nebauer; J. Aichelin

1998-11-05

96

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

NASA Technical Reports Server (NTRS)

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.

Kousen, Kenneth A.

1999-01-01

97

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

SciTech Connect

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.

Arnaldi, R.; Colla, A.; Cortese, P.; Ferretti, A.; Oppedisano, C.; Scomparin, E. [Universita di Torino and INFN, Turin (Italy); Banicz, K.; Damjanovic, S. [CERN, 1211 Geneva 23 (Switzerland); Physikalisches Institut der Universitaet Heidelberg, Heidelberg (Germany); Castor, J.; Devaux, A.; Fargeix, J.; Force, P.; Manso, F. [LPC, Universite Blaise Pascal and CNRS-IN2P3, Clermont-Ferrand (France); Chaurand, B. [LLR, Ecole Polytechnique and CNRS-IN2P3, Palaiseau (France); Cicalo, C.; Falco, A. de; Floris, M.; Masoni, A.; Puddu, G.; Serci, S. [Universita di Cagliari and INFN, Cagliari (Italy)] (and others)

2008-01-18

98

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

PubMed

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

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

2015-02-01

99

Theoretical analysis of incompressible flow through a radial-inlet centrifugal impeller at various weight flows  

NASA Technical Reports Server (NTRS)

A method for the solution of the incompressible nonviscous flow through a centrifugal impeller, including the inlet region, is presented. Several numerical solutions are obtained for four weight flows through an impeller at one operating speed. These solutions are refined in the leading-edge region. The results are presented in a series of figures showing streamlines and relative velocity contours. A comparison is made with the results obtained by using a rapid approximate method of analysis.

Kramer, James J; Prian, Vasily D; Wu, Chung-Hua

1956-01-01

100

Comparison of flow characteristics and vascular reactivity of radial artery and long saphenous vein grafts [NCT00139399  

Microsoft Academic Search

BACKGROUND: The morphological and functional differences between arteries and veins may have implications on coronary artery bypass graft (CABG) survival. Although subjective differences have been observed between radial artery (RA) and long saphenous venous (LSV) grafts, these have not been quantified. This study assessed and compared the flow characteristics and in-vivo graft flow responses of RA and LSV aorto-coronary grafts.

William CF Chong; Peter Collins; Carolyn M Webb; Anthony C De Souza; John R Pepper; Christopher S Hayward; Neil E Moat

2006-01-01

101

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

E-print Network

On the nature of radial transport across sheared zonal flows in electrostatic ion-temperature-gradient, incomplete. By means of toroidal gyrokinetic simulations of electrostatic, ion-temperature-gradient by the presence of a sheared zonal flow, changing from diffusive to anticorrelated and subdiffusive. Furthermore

Newman, David

102

Electrosonic spray ionization—An ideal interface for high-flow liquid chromatography applications  

Microsoft Academic Search

Electrosonic spray ionization (ESSI) has been studied as an interface between high-performance liquid chromatography (HPLC) and mass spectrometry (MS), using sample flow rates up to 3.0mlmin?1. This ionization interface was compared with pneumatically assisted electrospray ionization (ESI) using mass spectrometry for detection. For experiments that did not involve direct comparison of different flow rates, the ESI experiments were performed using

Stefan Schmid; Matthias C. Jecklin; Renato Zenobi

2011-01-01

103

An interactive grid generation procedure for axial and radial flow turbomachinery  

NASA Astrophysics Data System (ADS)

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

Beach, T. A.

1990-01-01

104

An interactive grid generation procedure for axial and radial flow turbomachinery  

NASA Technical Reports Server (NTRS)

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

Beach, Timothy A.

1989-01-01

105

Radial-radial single rotor turbine  

DOEpatents

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.

Platts, David A. (Los Alamos, NM)

2006-05-16

106

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

NASA Technical Reports Server (NTRS)

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.

Englert, Gerald W.; Kochendorfer, Fred D.

1959-01-01

107

Acoustic geometry through perturbation of mass accretion rate : I - radial flow in general static spacetime  

E-print Network

We propose a novel perturbation scheme to perform the linear stability analysis of stationary transonic integral accretion solutions corresponding to the hydrodynamic non self-gravitating radial flow of matter in a general static black hole spacetime. We demonstrate that a metric independent perturbation scheme can be developed, which leads to the emergence of the relativistic acoustic geometry and ensures the stability of the background stationary solutions. The acoustic metric obtained by perturbing the mass accretion rate rate is found to be identical with that obtained through the perturbation of the velocity potential. Our work thus makes a crucial connection between two apparently disjoint fields of study - accretion astrophysics and analogue gravity phenomena. We also formally prove that acoustic horizons never form in the Rindler spacetime.

Deepika B. Ananda; Sourav Bhattacharya; Tapas K. Das

2014-08-08

108

Performance back-deduction from a loading to flow coefficient map: Application to radial turbine  

NASA Astrophysics Data System (ADS)

Radial turbine stages are often used for applications requiring off-design operation, as turbocharging for instance. The off-design ability of such stages is commonly analyzed through the traditional turbine map, plotting the reduced mass-flow against the pressure-ratio, for reduced-speed lines. However, some alternatives are possible, such as the flow-coefficient ( ?) to loading-coefficient ( ?) diagram where the pressure-ratio lines are actually straight lines, very convenient property to perform prediction. A robust method re-creating this map from a predicted ?-? diagram is needed. Recent work has shown that this back-deduction quality, without the use of any loss models, depends on the knowledge of an intermediate pressure-ratio. A modelization of this parameter is then proposed. The comparison with both experimental and CFD results is presented, with quite good agreement for mass flow rate and rotational speed, and for the intermediate pressure ratio. The last part of the paper is dedicated to the application of the intermediate pressure-ratio knowledge to the improvement of the deduction of the pressure ratio lines in the ?-? diagram. Beside this improvement, the back-deduction method of the classical map is structured, applied and evaluated.

Carbonneau, Xavier; Binder, Nicolas

2012-12-01

109

Aerodynamic design of turbomachinery blading in three-dimensional flow - An application to radial inflow turbines  

NASA Technical Reports Server (NTRS)

A computational method, based on a theory for turbomachinery blading design in three-dimensional inviscid flow, is applied to a parametric design study of a radial inflow turbine wheel. As the method requires the specification of swirl distribution, a technique for its smooth generation within the blade region is proposed. Excellent agreements have been obtained between the computed results from this design method and those from direct Euler computations, demonstrating the correspondence and consistency between the two. The computed results indicate the sensitivity of the pressure distribution to a lean in the stacking axis and a minor alteration in the hub/shroud profiles. Analysis based on Navier-Stokes solver shows no breakdown of flow within the designed blade passage and agreement with that from design calculation; thus the flow in the designed turbine rotor closely approximates that of an inviscid one. These calculations illustrate the use of a design method coupled to an analysis tool for establishing guidelines and criteria for designing turbomachinery blading.

Yang, Y. L.; Tan, C. S.; Hawthorne, W. R.

1992-01-01

110

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

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

111

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

SciTech Connect

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.

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

1999-07-01

112

Effect of a constant radial temperature gradient on a Taylor-Couette flow with axial wall slits  

NASA Astrophysics Data System (ADS)

The flow between two concentric cylinders with the inner cylinder rotating with an imposed radial temperature gradient was studied using the digital particle image velocimetry method. Four models of a stationary outer cylinder without and with different numbers of slits (6, 9 and 18) were used. The Grashof number in this study was 1000. The results showed clearly that the buoyant force due to the temperature gradient caused the helical flow; this flow occurred when the Richardson number was larger than 0.0045. The constant temperature gradient considered in this research has little effect on the transition to a turbulent Taylor vortex flow in all models.

Liu, Dong; Lee, Sang-Hyuk; Kim, Hyoung-Bum

2010-12-01

113

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

USGS Publications Warehouse

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.

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

2001-01-01

114

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...

115

Probing f-actin flow by tracking shape fluctuations of radial bundles in lamellipodia of motile cells.  

PubMed Central

We examined the dynamics of radial actin bundles based on time-lapse movies of polarized light images of living neuronal growth cones. Using a highly sensitive computer vision algorithm for tracking, we analyzed the small shape fluctuations of radial actin bundles that otherwise remained stationary in their positions in the growth cone lamellipodium. Using the tracking software, we selected target points on radial bundles and measured both the local bundle orientations and the lateral displacements between consecutive movie frames. We found that the local orientation and the lateral displacement of a target point are correlated. The correlation can be explained using a simple geometric relationship between the lateral travel of tilted actin bundles and the retrograde flow of f-actin structures. Once this relationship has been established, we have turned the table and used the radial bundles as probes to measure the velocity field of f-actin flow. We have generated a detailed map of the complex retrograde flow pattern throughout the lamellipodium. Such two-dimensional flow maps will give new insights into the mechanisms responsible for f-actin-mediated cell motility and growth. PMID:10866947

Danuser, G; Oldenbourg, R

2000-01-01

116

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

NASA Astrophysics Data System (ADS)

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

Guillou, Erwann

117

Abstract--In this paper, Reversed-Flow Gas Chromatography (RF-GC) is utilized to investigate the  

E-print Network

Abstract--In this paper, Reversed-Flow Gas Chromatography (RF-GC) is utilized to investigate Chromatography (RF-GC) method can be used as an indicator to `measure' the evaporation rates of liquid Manuscript by a factor of 46-50% [16-22]. This paper demonstrates the utilization of RF-GC in the study of evaporation

Paris-Sud XI, Université de

118

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

Microsoft Academic Search

There is an increasing interest in screening methods for quick and sensitive analysis of various classes of veterinary drugs\\u000a with limited sample pre-treatment. Turbulent flow chromatography in combination with tandem mass spectrometry has been applied\\u000a for the first time as an efficient screening method in routine analysis of milk samples. Eight veterinary drugs, belonging\\u000a to seven different classes were selected

Alida A. M. Stolker; Ruud J. B. Peters; Richard Zuiderent; Joseph M. DiBussolo; Cláudia P. B. Martins

2010-01-01

119

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

120

Venous drainage of the radial forearm and anterior tibial reverse flow flaps: anatomical and radiographic perfusion studies.  

PubMed

The anatomy of the venous system in the pedicles of the radial forearm and anterior tibial reverse flow flaps was investigated in fresh cadavers (n = 6) and their drainage pathways were observed in a radiographic perfusion study of the veins of 2 radial forearm and 2 anterior tibial pedicles. The venous system was found to consist mainly of three types of veins: venae comitantes, communicating veins between the venae comitantes, and vasa vasorum. Valves were identified in all three types of vein. In the venous system, including the vasa vasorum, there was no route of reverse flow that did not pass directly through valves. Valve incompetence was demonstrated in the radiographic perfusion study. However, valve incompetence did not occur in all valves and a difference in valve resistance against reverse flow pressure existed. Veins with relatively weak valve resistance became the drainage pathway. A possible cause of the difference in valve resistance was differences in the anatomy of the valve sinuses. PMID:9326141

Nakajima, H; Imanishi, N; Aiso, S; Fujino, T

1997-09-01

121

Hepatic reconstruction from fetal porcine liver cells using a radial flow bioreactor  

PubMed Central

AIM: To examine the efficacy of the radial flow bioreactor (RFB) as an extracorporeal bioartificial liver (BAL) and the reconstruction of liver organoids using embryonic pig liver cells. METHODS: We reconstructed the liver organoids using embryonic porcine liver cells in the RFB. We also determined the gestational time window for the optimum growth of embryonic porcine liver cells. Five weeks of gestation was designated as embryonic day (E) 35 and 8 wk of gestation was designated as E56. These cells were cultured for one week before morphological and functional examinations. Moreover, the efficacy of pulsed administration of a high concentration hepatocyte growth factor (HGF) was examined. RESULTS: Both cell growth and function were excellent after harvesting on E35. The pulsed administration of a high concentration of HGF promoted the differentiation and maturation of these fetal hepatic cells. Microscopic examination of organoids in the RFB revealed palisading and showed that bile duct-like structures were well developed, indicating that the organoids were mini livers. Transmission electron microscopy revealed microvilli on the luminal surfaces of bile duct-like structures and junctional complexes, which form the basis of the cytoskeleton of epithelial tissues. Furthermore, strong expression of connexin (Cx) 32, which is the main protein of hepatocyte gap junctions, was observed. With respect to liver function, ammonia detoxification and urea synthesis were shown to be performed effectively. CONCLUSION: Our system can potentially be applied in the fields of BAL and transplantation medicine. PMID:18461659

Ishii, Yuji; Saito, Ryota; Marushima, Hideki; Ito, Ryusuke; Sakamoto, Taro; Yanaga, Katsuhiko

2008-01-01

122

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

NASA Astrophysics Data System (ADS)

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 Brunt-Väisälä frequency.

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

2015-03-01

123

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

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

124

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

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

125

Radial flow in Au+Au collisions at {ital E}=(0.25--1.15){ital A} GeV  

SciTech Connect

A systematic study of energy spectra for light particles emitted at midrapidity from Au+Au collisions at {ital E}= (0.25--1.15){ital A} GeV reveals a significant nonthermal component consistent with a collective radial flow. This component is evaluated as a function of bombarding energy and event centrality. Comparisons to quantum molecular dynamics and Boltzmann-Uehling-Uhlenbeck models are made for different equations of state.

Lisa, M.A.; Albergo, S.; Bieser, F.; Brady, F.P.; Caccia, Z.; Cebra, D.A.; Chacon, A.D.; Chance, J.L.; Choi, Y.; Costa, S.; Elliott, J.B.; Gilkes, M.L.; Hauger, J.A.; Hirsch, A.S.; Hjort, E.L.; Insolia, A.; Justice, M.; Keane, D.; Kintner, J.; Matis, H.S.; McMahan, M.; McParland, C.; Olson, D.L.; Partlan, M.D.; Porile, N.T.; Potenza, R.; Rai, G.; Rasmussen, J.; Ritter, H.G.; Romanski, J.; Romero, J.L.; Russo, G.V.; Scharenberg, R.; Scott, A.; Shao, Y.; Srivastava, B.K.; Symons, T.J.M.; Tincknell, M.; Tuve, C.; Wang, S.; Warren, P.; Westfall, G.D.; Wieman, H.H.; Wolf, K. [Nuclear Science Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)] [Nuclear Science Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States); [Kent State University, Kent, Ohio 44242 (United States); [Purdue University, West Lafayette, Indiana 47907-1396 (United States); [University of California, Davis, California 95616 (United States); [Texas A& M University, College Station, Texas 77843 (United States); [Universita di Catania & INFN-Sezione di Catania, Catania, Italy 95129 (United States); [NSCL, Michigan State University, East Lansing, Michigan 48824 (United States); (EOS Collaboration)

1995-10-02

126

A viscous flow study of shock-boundary layer interaction, radial transport, and wake development in a transonic compressor  

NASA Technical Reports Server (NTRS)

A numerical study based on the 3D Reynolds-averaged Navier-Stokes equation has been conducted to investigate the detailed flow physics inside a transonic compressor. 3D shock structure, shock-boundary layer interaction, flow separation, radial mixing, and wake development are all investigated at design and off-design conditions. Experimental data based on laser anemometer measurements are used to assess the overall quality of the numerical solution. An additional experimental study to investigate end-wall flow with a hot-film was conducted, and these results are compared with the numerical results. Detailed comparison with experimental data indicates that the overall features of the 3D shock structure, the shock-boundary layer interaction, and the wake development are all calculated very well in the numerical solution. The numerical results are further analyzed to examine the radial mixing phenomena in the transonic compressor. A thin sheet of particles is injected in the numerical solution upstream of the compressor. The movement of particles is traced with a 3D plotting package. This numerical survey of tracer concentration reveals the fundamental mechanisms of radial transport in this transonic compressor.

Hah, Chunill; Reid, Lonnie

1991-01-01

127

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

PubMed Central

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

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

2009-01-01

128

Preparation of diethylaminoethyl hollow fibres for high-flow liquid chromatography.  

PubMed

A novel anion-exchange column for fast-flow liquid chromatography was developed. The column was prepared by immobilizing diethylaminoethyl groups on to the inner walls of regenerated cellulose hollow fibres. A detailed investigation was conducted of the parameters affecting diethylaminoethyl immobilization such as the NaOH concentration, the reaction temperature, the diethylaminoethyl concentration and the reaction span. Based upon the findings, a protocol to optimize the preparation of the diethylaminoethyl hollow fibres was established. The diethylaminoethyl hollow fibres prepared adsorbed 186 +/- 30 mg of albumin/g fibres. PMID:2090312

Tsuei, A C; Yang, V C

1990-11-01

129

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

NASA Technical Reports Server (NTRS)

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.

Mungur, P.; Kapur, A.

1974-01-01

130

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

PubMed

We report the e-beam radiolysis of polychlorinated biphenyls (PCBs) in a continuous flow system, and the development of remote, real-time detection using gas chromatography. Aroclor-containing transformer oil was recirculated through an irradiation cell irradiated with 13-MeV electrons, at a flow rate of approximately 0.1L/min. The analytical equipment was protected from the beam by a 1.1-m concrete barrier. Data are presented showing the decrease in PCB concentration versus absorbed dose for pure transformer oil solution, and oil spiked with alkaline isopropanol to increase the PCB decomposition rate. Efficiency of PCB removal is expressed in terms of the dose constant, with units of reciprocal dose. PMID:16356731

Ruhter, Aaron; Rodriguez, Rene' G; Mincher, Bruce J; Brey, Richard R

2006-05-01

131

A comparison of the calculated and experimental off-design performance of a radial flow turbine  

NASA Technical Reports Server (NTRS)

Off design aerodynamic performance of the solid version of a cooled radial inflow turbine is analyzed. Rotor surface static pressure data and other performance parameters were obtained experimentally. Overall stage performance and turbine blade surface static to inlet total pressure ratios were calculated by using a quasi-three dimensional inviscid code. The off design prediction capability of this code for radial inflow turbines shows accurate static pressure prediction. Solutions show a difference of 3 to 5 points between the experimentally obtained efficiencies and the calculated values.

Tirres, Lizet

1991-01-01

132

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

PubMed

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

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

2015-01-01

133

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

USGS Publications Warehouse

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.

Reilly, Thomas E.

1984-01-01

134

A Laplace transform solution for tracer tests in a radially convergent flow field with upstream dispersion  

Microsoft Academic Search

When tracers are introduced into an injection borehole, noticeable concentration gradients at the injection well may cause a backward spreading of the initial plume during radially convergent tracer tests. Based on this concept a non-rigorous mathematical model is developed to estimate the effect of backward spreading. The injection well with an instantaneous slug input is treated as a mathematical source

Jui-Sheng Chen; Chen-Wuing Liu; Chia-Shyun Chen; Hun-Der Yen

1996-01-01

135

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

NASA Astrophysics Data System (ADS)

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.

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

2012-08-01

136

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

SciTech Connect

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

Schuster, Eugenio

2014-05-02

137

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

Microsoft Academic Search

The use of optical fibers in a fluorescence-detection scheme permits the accurate determination of the radial distribution of the transit time, the column efficiency, and the analyte concentration at the exit of a chromatographic axial-compression column (50 mmID). The results obtained demonstrate that the column is not homogeneous, but suggest a nearly cylindrical distribution of the packing density. The average

Tivadar Farkas; Michael J. Sepaniak; Georges Guiochon

1997-01-01

138

First-passage-time transfer functions for groundwater tracer tests conducted in radially convergent flow  

Microsoft Academic Search

Forced-gradient groundwater tracer tests may be conducted using a variety of hydraulic schemes, so it is useful to have simple semi-analytic models available that can examine various injection\\/withdrawal scenarios. Models for radially convergent tracer tests are formulated here as transfer functions, which allow complex tracer test designs to be simulated by a series of simple mathematical expressions. These mathematical expressions

Matthew W. Becker; Randall J. Charbeneau

2000-01-01

139

Reverse-flow radial forearm flap for reconstruction of the hand.  

PubMed

Soft-tissue injuries of the hand often require flap coverage to achieve primary wound closure and a good functional result. The use of the reverse radial forearm fasciocutaneous flap in the reconstruction of the hand is discussed. This flap offers thin, pliable, hairless skin and has proved very reliable because of its excellent vascular supply. The anatomy and vascular basis of this flap are presented along with its application in three patients. PMID:7857049

Mandrekas, A D; Zambacos, G J

1994-11-01

140

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

PubMed

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. PMID:24674643

Shendruk, T N; Slater, G W

2014-04-25

141

Enzymatic digestion and liquid chromatography in micropillar reactors: hydrodynamic versus electro-osmotic flow  

NASA Astrophysics Data System (ADS)

Enzymatic digestion and peptide separation are basic steps for preparation of protein samples prior to their analysis by mass spectrometry. Micro-pillar reactors for digestion and reverse phase liquid chromatography were designed and constructed using semiconductor technologies. The performances of the micro-machined reactors were evaluated: complete Cytochrome C digestion was achieved in 6 min for a concentration up to 25 pmol?l-1 and the separation micro-column was seen to exhibit separation capabilities and capacity close to those obtained with a commercial column. Furthermore, a comparative study between hydrodynamic and electroosmotic driven flows was performed for each peptide of a Cytochrome C digest. It was demonstrated that parasitic electrophoretic phenomena disturbed peptide mobility but not protein identification.

Sarrut, Nicolas; Bouffet, Stephanie; Mittler, Frederique; Constantin, Olivier; Combette, P.; Sudor, Jan; Ricoul, Florence; Vinet, Francoise; Garin, Jerome; Vauchier, Claude

2005-01-01

142

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

SciTech Connect

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

Batool, Nazia; Saleem, H. [National Centre for Physics (NCP), Quaid-i-Azam University Campus, Islamabad (Pakistan)] [National Centre for Physics (NCP), Quaid-i-Azam University Campus, Islamabad (Pakistan)

2013-10-15

143

Plastic ELISA-on-a-chip based on sequential cross-flow chromatography.  

PubMed

A plastic chip that can perform immunoassays using an enzyme as signal generator, i.e., ELISA-on-a-chip, was developed by incorporating an immunostrip into channels etched on the surfaces of the chip. To utilize an analytical concept of cross-flow chromatography, the chip consisted of two cross-flow channels in the horizontal and vertical directions. In the vertical channel, we placed a 2-mm-wide immunostrip for cardiac troponin I (cTnI), which was identical to a conventional rapid test kit except for the utilization of an enzyme, horseradish peroxidase (HRP), as tracer. An enzyme substrate supply channel and a horizontal flow absorption pad compartment were transversely arranged on each lateral side of the signal generation pad of the strip, respectively. Upon application of a sample containing cTnI, it migrated vertically through the membrane strip by capillary action, and antigen-antibody binding occurred. After 15 min, the horizontal flow was initiated by the addition of a chromogenic substrate solution for HRP into the supply channel and by partial superimposition of the horizontal flow absorption pad onto the signal generation pad. A color signal proportional to the analyte concentration was produced on this pad, measured after 5 min as optical densities using a digital camera-based detector, and quantified by integration of the densities under the peak after normalization. Its calibration curve indicated that the detection limit of the chip was approximately 0.1 ng/mL and its quantification limit was 0.25 ng/mL. In measuring blindly prepared samples, the chip performance correlated with that of a reference system, Beckman Coulter Access, within 2.5-fold discrepancy at the detection limit. PMID:16448053

Cho, Joung-Hwan; Han, Seung-Mok; Paek, Eui-Hwan; Cho, Il-Hoon; Paek, Se-Hwan

2006-02-01

144

Unsteady flow evolution in swirl injectors with radial entry. II. External excitations  

NASA Astrophysics Data System (ADS)

Our previous study on turbulent flows in a gas-turbine swirl injector was extended to explore the effects of externally impressed excitations on the unsteady flow evolution. Three-dimensional large-eddy simulations were conducted to investigate the responses of the injector flowfield by imposing periodical oscillations of the mass flow rate at the entrance over a wide range of frequencies. Results show that the impressed disturbances are decomposed and propagate in two different modes because of their distinct propagating mechanisms in swirl injectors. The flow oscillation in the streamwise direction travels in the form of acoustic wave, whereas the oscillation in the circumferential direction is convected downstream with the local flow velocity. The vortex breakdown is mainly controlled by the dynamics in the core region near the axis, not so much by the excitation in the main flow passage surrounding the central recirculation zone. External excitations only exert minor influences on the mean flow properties due to the broadband characteristics of the injector flow. One exception is in the outer shear-layer region when the forcing frequency matches the intrinsic frequency of vortex shedding, and the mixing process of two counter-rotating swirl flows is considerably enhanced. The dynamic response of the injector flow, however, depends significantly on the forcing frequency in terms of the acoustic admittance and the mass transfer functions. Energy can be transferred among the various structures in the flowfield under external excitations, causing highly nonuniform spatial and temporal distributions of the oscillatory flow properties at the injector exit. The mass transfer function between the injector exit and entrance at the forcing frequency could be substantially greater than unity when the disturbance resonates with the injector flow. The injector essentially acts as an amplifier under this condition.

Wang, Shanwu; Yang, Vigor

2005-04-01

145

THE COMPACTNESS OF FRONT TRACKING FOR CHROMATOGRAPHY ELECTROPHORESIS AND INCOMPRESSIBLE MULTIPHASE FLOW  

E-print Network

THE COMPACTNESS OF FRONT TRACKING FOR CHROMATOGRAPHY ELECTROPHORESIS AND INCOMPRESSIBLE MULTIPHASE. SUMMARY An analysis of the equations of chromatography from the point of view of hyperbolic conservation a subsequence converging to a weak solution of the chromatography equations, with no restriction on the size

146

Viscoelastic flow-focusing in microchannels: scaling properties of the particle radial distributions.  

PubMed

Particles suspended in non-Newtonian liquids flowing in channels may migrate transversally to the main flow direction as a result of normal stress gradients. Viscoelasticity-induced migration has proven to be an efficient mechanism to promote 3D flow-focusing in cylindrical microchannels, avoiding the need for complex and expensive apparati. In this work, we demonstrate the existence of a single dimensionless number (?) that governs the migration dynamics of particles in viscoelastic liquids flowing in micropipes at low Deborah numbers (Deborah number is the ratio of fluid and flow characteristic times). The definition of ? in terms of the relevant fluid, flow and geometrical quantities is obtained by generalizing the particle migration velocity expression given in previous asymptotic analytical theories through numerical simulations. An extensive experimental investigation quantitatively confirms the novel predictions: the experimental particle distributions along the channel axial direction collapse on a single curve when rescaled in terms of the proposed dimensionless number. The results reported in this work give a simple and general way to define the flow-focusing conditions promoted by viscoelastic effects. PMID:23670133

Romeo, Giovanni; D'Avino, Gaetano; Greco, Francesco; Netti, Paolo A; Maffettone, Pier Luca

2013-07-21

147

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

SciTech Connect

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

Clerc, T.; Hebert, A. [Institut de Genie Nucleaire, Station Centre-Ville, Montreal, QC, H3C 3A7 (Canada); Leroyer, H.; Argaud, J. P.; Poncot, A.; Bouriquet, B. [Electricite de France, R and D, SINETICS, 1 Av. du General de Gaulle, 92141, Clamart (France)

2013-07-01

148

The investigation of flow instabilities on a rotating disk with curvature in the radial direction  

NASA Technical Reports Server (NTRS)

The major objective is to explore any visible differences of the flow field with wall curvature of the test body, including possible interaction between Taylor-Gortler instabilities present along concave walls and the inflexional instabilities investigated here. An experimental study was conducted with emphasis placed on making visual observations and recording photographically the flow instabilities present under three different rotating bodies: a flat disk, a concave paraboloid, and a convex paraboloid. The data collected for the three test bodies lead to the conclusion that the wall curvature of the concave and convex paraboloids did not alter the observed flow field significantly from that observed on the flat disk.

Intemann, P. A.; Clarkson, M. H.

1982-01-01

149

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

PubMed

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. PMID:25591400

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

2015-02-01

150

Investigation of subsonic and supersonic flow in a radial inflow compressor  

E-print Network

Patent Office, 3305165, Feb. 21, 1967. 3. Hamrick, Joseph T. , Gimsburg, Amrose, Osborne, Walter, Method. of analysis for compressible flow through mixed flow centrifugal impellers of ar'oitrary design. NACA Rep. 1082, 1952. 4. Stanitz, John D.... and Prian, Vasily D. , A rapid approximation method for determining velocity distribution on impeller blades of centrifugal compressors. NACA TN 2421. 5. Stockman, N. 0. and Kramer, J. L. , Method fo" desigr. of punp impellers using a high speed digital...

Bale, Yadiyurappa Siddaveerasetty

1970-01-01

151

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

SciTech Connect

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.

Flathers, M.B. [Solar Turbines Inc., San Diego, CA (United States); Bache, G.E. [Advanced Scientific Computing Corp., El Dorado Hills, CA (United States); Rainsberger, R. [XYZ Scientific Applications Inc., Livermore, CA (United States)

1996-04-01

152

Investigation of the flow in a radial compressor and its excitation effect of blade vibration  

SciTech Connect

In the design of modern centrifugal compressors stress and vibration problems are of increasing importance. Results of research work in this field is presented about stress calculations due to centrifugal force and an evaluation of the lift forces by means of flow data. Flow measurements were discussed investigating the excitation effect to the blades. Vibration measurements telemetered from 8 blades were carried out on the compressor with vaneless and vaned diffuser. Vibration of the whole impeller is the subject of a FE-calculation.

Haupt, U.; Rautenberg, M.

1984-08-01

153

The three-dimensional compressible flow in a radial inflow turbine scroll  

NASA Technical Reports Server (NTRS)

This work presents the results of an analytical study and an experimental investigation of the three-dimensional flow in a turbine scroll. The finite element method is used in the iterative numerical solution of the locally linearized governing equations for the three-dimensional velocity potential field. The results of the numerical computations are compared with the experimental measurements in the scroll cross sections, which were obtained using laser Doppler velocimetry and hot wire techniques. The results of the computations show a variation in the flow conditions around the rotor periphery which was found to depend on the scroll geometry.

Hamed, A.; Tabakoff, W.; Malak, M.

1984-01-01

154

Nature Macmillan Publishers Ltd 1998 momentum, and so flow in radially. Such  

E-print Network

`Bondi­Hoyle' flows have very low radiation efficiencies. Melia then showed that a 10­4 -solar-mass yr­1 for a 2.6-million-solar-mass black hole accreting at 10­4 solar masses per year. Like Melia's Bondi

Columbia University

155

Automatic system to control radial gas-flow distribution parameters in the blast-furnace stack  

Microsoft Academic Search

and instruments for controlling the distribution of the gas flow across the stack of blast furnaces. This is because the proportion of indirectly reduced iron represents a significant part of the material and heat balances in blast-furnace smelting, determining the technicoeconomic indices of furnace operation. The importance of this work has increased in recent years in connection with the construction

I. A. Rylov; M. M. Shmonin; V. A. Makarychev; V. M. Yanchevskii; O. R. Basargin; A. P. Kalinin

1980-01-01

156

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

SciTech Connect

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

Chertkov, Michael [Los Alamos National Laboratory; Turitsyn, Konstantin [Los Alamos National Laboratory; Backhaus, Scott [Los Alamos National Laboratory; Sule, Petr [NEW MEXICO CONSORTIUM

2009-01-01

157

Purification of hemoglobin by ion exchange chromatography in flow-through mode with PEG as an escort.  

PubMed

Development of hemoglobin-based blood substitutes requires production of highly purified hemoglobin. Process of hemoglobin purification by ion exchange chromatography in flow-through mode was researched and optimized. Three kinds of media including, QMA Spherosil LS (Biosepra, France) and Q Sepharose Big Beads (Amersham Bioscience, Sweden), and an anion exchange membrane column, Mustang Q (PALL, USA) were investigated and compared. Adding polyethylene glycol (PEG) as an escort in ion exchange chromatography improved the purity and recovery, and the recovery in the chromatography was increased from 75 to 95%. The mechanism of PEG effects on chromatography was discussed. The optimal chromatography step, in combination with hypotonic dilution hemolyzing and membrane separation, formed an integrated hemoglobin purification process. The total recovery in the process was 87.6%. The activity of hemoglobin was well preserved: P50 23.2 mmHg, and Hill coefficient 2.31. The product appeared as a single band in SDS-PAGE, and GF-HPLC showed only one peak. The purity of the prepared hemoglobin was more than 99.9%. The optimized process is time saving and suitable for large-scale preparation of hemoglobin to provide materials for further preparation of blood substitutes. PMID:15274429

Lu, Xiuling; Zhao, Dongxu; Su, Zhiguo

2004-05-01

158

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

PubMed

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

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

2011-05-27

159

Determination of aromatic hydrocarbons in gasolines by flow modulated comprehensive two-dimensional gas chromatography.  

PubMed

Valve based/flow modulated comprehensive two-dimensional gas chromatography-flame ionization detection (GC x GC-FID) was used for quantification of C6 through C12 aromatic hydrocarbons by carbon number in gasolines. A 0.53 mm i.d. non-polar first dimension column was coupled to a 0.53 mm i.d. polar second dimension column through a double loop eight port valve modulator. Depending on the sample type, normalized percent and internal standard (I.S.) quantification was performed. For normalized percent quantification, a one-point calibration performed with one aromatic compound per carbon number/class provided an average % accuracy of 2.1% and a short-term n--1 relative standard deviation of 1.0%. For total aromatic compounds good agreement with the more complex conventional multidimensional GC technique was obtained. However, GC x GC has certain advantages over most other methods, mainly increased selectivity for total and carbon number aromatic content. The identification of the aromatic hydrocarbons was confirmed by GC x GC-MS. PMID:16008054

Diehl, John W; Di Sanzo, Frank P

2005-07-01

160

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

PubMed

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 depth. PMID:25757298

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

2014-09-01

161

A variant of circular thin-layer chromatography with a forced flow of the mobile phase produced by an electroosmotic pump  

NASA Astrophysics Data System (ADS)

A new variant of circular thin-layer chromatography (TLC) with a closed sorption layer in which a forced flow of the mobile phase was produced and controlled by an external electroosmotic pump placed at the center of a TLC plate was suggested. It was shown experimentally that the method operated properly and could be used in planar chromatography.

Berezkin, V. G.; Nekhoroshev, G. A.

2007-11-01

162

Analytical and Experimental Study of Flow Through an Axial Turbine Stage with a Nonuniform Inlet Radial Temperature Profile  

NASA Technical Reports Server (NTRS)

Results are presented for a typical nonuniform inlet radial temperature profile through an advanced single-stage axial turbine and compared with the results obtained for a uniform profile. Gas temperature rises of 40 K to 95 K are predicted at the hub and tip corners at the trailing edges of the pressure surfaces in both the stator and rotor due to convection of hot fluid from the mean by the secondary flow. The inlet temperature profile is shown to be mixed out at the rotor exit survey plane (2.3 axial chords downstream of the rotor trailing edge) in both the analysis and the experiment. The experimental rotor exit angle profile for the nonuniform inlet temperature profile indicates underturning at the tip caused by increased clearance. Severe underturning also occurs at the mean, both with and without the nonuniform inlet temperature profile. The inviscid rotational flow code used in the analysis fails to predict the underturning at the mean, which may be caused by viscous effects.

Schwab, J. R.; Stabe, R. G.; Whitney, W. J.

1983-01-01

163

Analytical and experimental study of flow through an axial turbine stage with a nonuniform inlet radial temperature profile  

NASA Technical Reports Server (NTRS)

Results are presented for a typical nonuniform inlet radial temperature profile through an advanced single-stage axial turbine and compared with the results obtained for a uniform profile. Gas temperature rises of 40 K to 95 K are predicted at the hub and tip corners at the trailing edges of the pressure surfaces in both the stator and rotor due to convection of hot fluid from the mean by the secondary flow. The inlet temperature profile is shown to be mixed out at the rotor exit survey plane (2.3 axial chords downstream of the rotor trailing edge) in both the analysis and the experiment. The experimental rotor exit angle profile for the nonuniform inlet temperature profile indicates underturning at the tip caused by increased clearance. Severe underturning also occurs at the mean, both with and without the nonuniform inlet temperature profile. The inviscid rotational flow code used in the analysis fails to predict the underturning at the mean, which may be caused by viscous effects. Previously announced in STAR as N83-27958

Schwab, J. R.; Stabe, R. G.; Whitney, W. J.

1983-01-01

164

Direct pharmacokinetic analysis of puqietinone by in vivo microdialysis sampling and turbulent-flow chromatography coupled with liquid chromatography-mass spectrometry.  

PubMed

Sample pretreatment is a key step in bioanalytical process because of possible interference and matrix effects in mass spectrometry analysis. In this work, a novel strategy towards high speed and sensitivity was developed combining in vivo microdialysis (MD) sampling, turbulent-flow chromatography (TFC), and liquid chromatography-mass spectrometry (LC-MS). The procedures of cleanup, preconcentration, and separation were completed on-line in one step within 10min. During the MD optimization procedure, 1% hydroxypropyl-?-cyclodextrin (HP-?-CD) was used to improve the relative recovery of the analyte. Untreated MD samples were directly injected, and a TFC precolumn was flushed for 1min with aqueous phase of 4mL/min flow rate to desalt and concentrate biosamples. The retained analytes were then back-flushed by a switching valve onto a fast LC column (4.6mm×50mm, 1.8?m) for separation. Another diverter valve was employed to prevent the HP-?-CD that interferes with the ESI process from entering the MS. Puqietinone, a lipophilic alkaloid from Fritillaria puqiensis, was used as a case for validation. Results showed that the limit of quantification for puqietinone was 0.10ng/mL, and good linearity (R(2)=0.9993) was maintained over the range of 1.02-200.02ng/mL. Accuracy and precision were satisfactory within the range of the standard curve. This approach was able to effectively eliminate the influences of matrix effect and carry-over as the injection volume increased up to 20?L. The developed method was successfully applied to pharmacokinetic study of puqietinone after intravenous administration to rat. Results demonstrate the potential of using MD with TFC-LC/MS for in vivo monitoring experiments. PMID:22658466

Xin, Gui-Zhong; Cao, Liu; Shi, Zi-Qi; Li, Hui-Jun; Wen, Xiao-Dong; Chen, Jun; Qi, Lian-Wen; Li, Ping

2012-06-15

165

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

PubMed Central

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

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

2014-01-01

166

Real-time phase-contrast MRI of cardiovascular blood flow using undersampled radial fast low-angle shot and nonlinear inverse reconstruction.  

PubMed

Velocity-encoded phase-contrast MRI of cardiovascular blood flow commonly relies on electrocardiogram-synchronized cine acquisitions of multiple heartbeats to quantitatively determine the flow of an averaged cardiac cycle. Here, we present a new method for real-time phase-contrast MRI that combines flow-encoding gradients with highly undersampled radial fast low-angle shot acquisitions and phase-sensitive image reconstructions by regularized nonlinear inversion. Apart from calibration studies using steady and pulsatile flow, preliminary in vivo applications focused on through-plane flow in the ascending aorta of healthy subjects. With bipolar velocity-encoding gradients of alternating polarity that overlap the slice-refocusing gradient, the method yields flow-encoded images with an in-plane resolution of 1.8 mm, section thickness of 6 mm and measuring time at 3 T of 24 ms (TR/TE?=?3.44/2.76 ms; flip angle, 10º; seven radial spokes per image). Accordingly, phase-contrast maps and corresponding velocity profiles achieve a temporal resolution of 48 ms. The evaluated peak velocities, stroke volumes, flow rates and respective variances over at least 20 consecutive heartbeats are in general agreement with literature data. PMID:22180216

Joseph, Arun A; Merboldt, Klaus-Dietmar; Voit, Dirk; Zhang, Shuo; Uecker, Martin; Lotz, Joachim; Frahm, Jens

2012-07-01

167

Improving quantification using curtain flow chromatography columns in the analysis of labile compounds: a study on amino acids.  

PubMed

The performance of curtain flow chromatography column technology with MS detection was evaluated for the analysis of labile compounds. The curtain flow column design allows for separations that are faster and/or more sensitive than conventional columns, depending on how exactly the curtain flow column is configured. For example, when mass spectral detection is employed, the curtain flow column can yield separations that are 5-times faster than conventional columns when the curtain flow and the conventional columns have the same internal diameter. Or when the internal diameter of the conventional column is reduced in order to yield the same analytical through-put as the curtain flow column, the sensitivity on the curtain flow column can be as much as 66-fold higher than the conventional column. As a consequence of the higher analytical through-put less standardization is required in the analysis of labile compounds because less sample degradation is apparent. Consequently the sample integrity is preserved yielding data of a higher quality. PMID:25497579

Kocic, D; Pereira, L; Edge, T; Ritchie, H; Conlan, X A; Shalliker, R A

2015-01-01

168

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

SciTech Connect

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

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

2000-03-30

169

Impact of the BEA zeolite morphology on isobutane adsorption followed by Reversed-Flow Inverse Gas Chromatography.  

PubMed

The mass transfer phenomena of isobutane (i-C4) were investigated at 343K on three protonic BEA zeolites. Defined by their crystallites sizes and degrees of aggregation, these samples were characterized by Reversed-Flow Inverse Gas Chromatography (RF-GC). This simple technique, used in conjunction with numerical computation, allowed the determination of physicochemical quantities like local monolayer capacities, probability density functions and diffusion coefficients in a time-resolved way. This study enabled to conclude that the effective diffusion coefficient was affected by the size of the zeolite agglomerate whereas the surface diffusion depended on the zeolite crystallite size. PMID:22964049

Batalha, N; Soualah, A; Pinard, L; Pouilloux, Y; Lemos, F; Belin, T

2012-10-19

170

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

PubMed Central

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

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

2014-01-01

171

Amino acid separation by preparative temperature-swing chromatography with flow reversal  

Microsoft Academic Search

A special type of adsorptive parametric pumping called temperature-swing chromatography is experimentally investigated for a new application: the separation of amino acids. Experiments have been done with a mixture of arginine, histidine and lysine in acidic solution (HCl). A multicomponent equilibrium model has been used to simulate the experimental results and to investigate some possible ways to improve the separation.

Gabor Simon; Laszlo Hanak; Georges Grévillot; Tibor Szanya; Gyula Marton

1996-01-01

172

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

PubMed

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

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

2013-01-01

173

The solution-adaptive numerical simulation of the three-dimensional viscous flow in the serpentine coolant passage of a radial inflow turbine blade  

SciTech Connect

This paper describes the application of a solution-adaptive, three-dimensional Navier-Stokes solver to the problem of the flow in turbine internal coolant passages. First, the variation of Nusselt number in a cylindrical, multiribbed duct is predicted and found to be in acceptable agreement with experimental data. Then the flow is computed in the serpentine coolant passage of a radial inflow turbine including modeling the internal baffles and pin fins. The aerodynamics of the passage, particularly that associated with the pin fins, is found to be complex. The predicted heat transfer coefficients allow zones of poor coolant penetration and potential hot spots to be identified.

Dawes, W.N. (Whittle Lab., Cambridge (United Kingdom))

1994-01-01

174

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

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

Berger, Terry A

2014-10-17

175

[Use of reverse flow pedicled osteo-fascio-cutaneous radial forearm flap in reconstruction of the first ray in the hand].  

PubMed

A reverse flow pedicled osteo-fascio-cutanous radial forearm flap was applied in different clinical situations. Treatment of 1 female patient--age 28 years, and 3 male patient--age 17, 29 and 33 years is presented. Indications for treatment were: congenital malformation of the thenar region and thumb, deficit of the soft tissue, of the IMP joint and a segment of the first metacarpal bone, amputation of the thumb at IMP level and congenital total absence of the first ray of the hand. The author's modification of total thumb reconstruction is presented. Some steps of the procedure, using osteo-fascio-cutaneous radial flap differed from the original Biemer and Stock method. Donor site was located on the medial and radial part of the forearm. The flap was planned, elevated longitudinally and folded over the vascularized radial bone graft. In thumb reconstruction cases no implants were used for bone fixation. Part of the radius was directly nailed into the distal part of the first metacarpal. Bone healing was observed after 6 weeks and its remodeling took nearly 6 months. There were no complications at the donor site (one was closed directly and two by skin grafts). Two flaps were remodeled because of soft tissue abundance. Functional and cosmetic results were good in all four cases. PMID:11144073

Molski, M

2000-01-01

176

Purification of plasmid DNA using tangential flow filtration and tandem anion-exchange membrane chromatography  

Microsoft Academic Search

A new bioprocess using mainly membrane operations to obtain purified plasmid DNA from Escherechia coli ferments was developed. The intermediate recovery and purification of the plasmid DNA in cell lysate was conducted using\\u000a hollow-fiber tangential filtration and tandem anion-exchange membrane chromatography. The purity of the solutions of plasmid\\u000a DNA obtained during each process stage was investigated. The results show that

Patricia Guerrero-Germán; Duarte M. F. Prazeres; Rosa Ma. Montesinos-Cisneros; Armando Tejeda-Mansir

2009-01-01

177

Turbulent-flow chromatography coupled on-line to fast high-performance liquid chromatography and mass spectrometry for simultaneous determination of verticine, verticinone and isoverticine in rat plasma  

Microsoft Academic Search

A method based on the on-line turbulent-flow chromatography and fast high-performance liquid chromatography\\/mass spectrometry (TFC–LC\\/MS) was developed for sensitive and high throughput pharmacokinetic study of traditional Chinese medicines (TCMs). In this method, an on-line extraction column (Waters Oasis HLB) and a fast HPLC column with sub-2?m particle size (Agilent Zorbax StableBond-C18, 4.6mm×50mm, 1.8?m) in a column-switching set-up were utilized. HLB

Gui-Zhong Xin; Jian-Liang Zhou; Lian-Wen Qi; Chang-Yin Li; Peng Liu; Hui-Jun Li; Xiao-dong Wen; Ping Li

2010-01-01

178

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

PubMed Central

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

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

2015-01-01

179

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

PubMed

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

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

2015-03-01

180

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

PubMed

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. PMID:24216209

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

2013-11-25

181

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

PubMed Central

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

Carter, Darren J.; Cary, R. Bruce

2007-01-01

182

Influence of heat and mass transfer, initial stress and radially varying magnetic field on the peristaltic flow in an annulus with gravity field  

NASA Astrophysics Data System (ADS)

In this paper, the effects of both initial stress, radially varying and gravity field on the peristaltic flow of an incompressible MHD Newtonian fluid in a vertical annulus have been studied under the assumption of long wavelength and low-Reynolds number. The analytical solution has been derived for the temperature, concentration and velocity. The results for velocity, concentration and temperature obtained in the analytical form have been evaluated numerically and discussed briefly. The effect of the non-dimensional wave amplitude, the coefficient of viscosity, Sort number, Schmidt number, initial stress, gravitational field and the dimensionless time-mean flow in the wave frame are analyzed theoretically and computed numerically. The expressions for pressure rise, temperature, concentration field, velocity and pressure gradient are sketched for various embedded parameters and interpreted. Numerical results are given and illustrated graphically in each case considered. Comparison was made with the results obtained in the presence and absence of initial stress and gravitational field.

Abd-Alla, A. M.; Abo-Dahab, S. M.; El-Shahrany, H. D.

2014-08-01

183

Stopping and radial flow in central {sup 58}Ni+{sup 58}Ni collisions between 1A and 2AGeV  

SciTech Connect

The production of charged pions, protons, and deuterons has been studied in central collisions of {sup 58}Ni on {sup 58}Ni at incident beam energies of 1.06A, 1.45A, and 1.93A GeV. The dependence of transverse-momentum and rapidity spectra on the beam energy and on the centrality of the collison is presented. It is shown that the scaling of the mean rapidity shift of protons established for between 10{ital A} and 200{ital A} GeV at the Brookhaven AGS and the CERN SPS accelerators energies is valid down to 1A GeV. The degree of nuclear stopping is discussed; quantum molecular dynamics calculations reproduce the measured proton rapidity spectra for the most central events reasonably well, but do not show any sensitivity between the soft and the hard equation of state. A radial flow analysis, using the midrapidity transverse-momentum spectra, delivers freeze-out temperatures T and radial flow velocities {beta}{sub r} which increase with beam energy up to 2A GeV; in comparison to the existing data of Au on Au over a large range of energies, only {beta}{sub r} shows a system size dependence. {copyright} {ital 1998} {ital The American Physical Society}

Buta, A.; Legrand, I.; Petrovici, M.; Simion, V. [Institute for Nuclear Physics and Engineering, Bucharest (Romania); Berek, G.; Fodor, Z.; Kecskemeti, J.; Seres, Z. [Central Research Institute for Physics, Budapest (Hungary); Alard, J.P.; Amouroux, V.; Bastid, N.; Dupieux, P.; Fraysse, L.; Genoux-Lubain, A.; Pras, P. [Laboratoire de Physique Corpusculaire, IN2P3/CNRS, and Universite Blaise Pascal, Clermont-Ferrand (France); Hong, B.; Herrmann, N.; Ritman, J.L.; Best, D.; Gobbi, A.; Hildenbrand, K.D.; Kirejczyk, M.; Leifels, Y.; Pinkenburg, C.; Reisdorf, W.; Schuell, D.; Sodan, U.; Wang, G.S.; Wienold, T. [Gesellschaft fuer Schwerionenforschung, Darmstadt (Germany); Biegansky, J.; Kotte, R.; Moesner, J.; Neubert, W.; Wohlfarth, D. [Forschungszentrum Rossendorf, Dresden (Germany); Herrmann, N.; Eskef, M.; Goebels, G.; Haefele, E.; Korolija, M.; Mohren, S.; Pelte, D.; Trzaska, M. [Physikalisches Institut der Universitaet Heidelberg, Heidelberg (Germany); Belyaev, I.; Lebedev, A.; Somov, A.; Zhilin, A. [Institute for Theoretical and Experimental Physics, Moscow (Russia); Manko, V.; Vasiliev, M.A. [Kurchatov Institute, Moscow (Russia); Coffin, J.P.; Crochet, P.; de Schauenburg, B.; Dona, R.; Fintz, P.; Guillaume, G.; Jundt, F.; Kuhn, C.; Maazouzi, C.; Rami, F.; Roy, C.; Tizniti, L.; Wagner, P. [Institut de Recherches Subatomiques, IN2P3-CNRS/ULP, Strasbourg (France); Kirejczyk, M.; Sikora, B.; Siwek-Wilczynska, K. [Institute of Experimental Physics, Warsaw University (Poland)

1998-01-01

184

Hollow fiber flow field-flow fractionation and size-exclusion chromatography with MALS detection: A complementary approach in biopharmaceutical industry.  

PubMed

Monoclonal antibodies (mAbs) are promising reagents both for the manufacture of drug substances and for their employment as a drug themselves, but to be approved for utilization, according to FDA recommendations and WHO guidelines, they have to undergo verifications regarding their purity, stability and percentage of aggregates. Moreover, stability tests of lots have to be performed in order to verify molecular size distribution over time and lot-to-lot consistency. Recent works in literature have highlighted the need for suitable, sensitive and reliable complementary analytical techniques for the characterization of mAbs and quantification of aggregates. Size-exclusion chromatography (SEC) is the reference technique in the biopharmaceutical industry for its robustness, high performance and simple use; however it presents some limitations especially toward the separation and detection of aggregates with high molecular weight. On the other hand, flow field-flow fractionation (F4) in its miniaturized version (hollow fiber flow field-flow fractionation, HF5) shows comparable performances with interesting additional advantages: a broad size range, gentle separation mechanism with low dilution factor and higher sensitivity. To propose HF5 as a complementary technique for evaluating aggregates' content in mAbs samples, a comparative study of both SEC and HF5 performances has been made. In this work, SEC and HF5 were coupled with UV and multi-angle light scattering detection and employed first in separating standard samples of proteins mixture used as a sample model. Then, a screening of mobile phases and an evaluation of separation performances was performed on a therapeutic mAbs formulation, demonstrating the complementarities between SEC and HF5 and their possible use as a separative platform approach for the characterization and quality control of protein drugs. PMID:25468501

Marassi, V; Roda, B; Zattoni, A; Tanase, M; Reschiglian, P

2014-10-30

185

Radial lean direct injection burner  

DOEpatents

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.

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

2012-09-04

186

Quantitation of anthracyclines in human hematopoietic cell subpopulations by flow cytometry correlated with high pressure liquid chromatography.  

PubMed

The major white cell subpopulations present in bone marrow and peripheral blood can be discriminated by forward and perpendicular light scatter two-parameter flow cytometry (FCM). Fluorescent properties of anthracycline antibiotics allow measurement of the concentration of these cytotoxic drugs in hematopoietic cells by FCM as a third parameter. Analysis of scatter-gated fluorescence histograms provides quantitative information about the cellular concentration of at least four cell categories in human blood and bone marrow cells. A good correlation was found between the mean cellular fluorescence measured by FCM and the overall cellular concentration of adriamycin, daunomycin, and their main metabolites determined with high-pressure liquid chromatography (HPLC). In incubation experiments with human hematopoietic tissues, the final concentration of various anthracyclines in subpopulations of white cells appeared to be dependent on cell density, incubation time, temperature, and type of compound and its concentration. FCM analysis is a rapid, sensitive, and quantitative method for measurement of cellular anthracycline concentrations in subpopulations and therefore provides an useful new tool in monitoring chemotherapy. PMID:3856510

Speth, P A; Linssen, P C; Boezeman, J B; Wessels, H M; Haanen, C

1985-03-01

187

Flow-modulated comprehensive two-dimensional gas chromatography with simultaneous flame ionization and quadrupole mass spectrometric detection.  

PubMed

Flow-modulated comprehensive two-dimensional gas chromatography with simultaneous monitoring of the separation by flame ionization (GC × GC-FID) and quadrupole mass spectrometric (GC × GC-qMSD) detection was studied for the analysis of gasoline and kerosene samples. The acquisition frequency of the FID was 100 Hz and of the qMSD 18 Hz for the mass range m/z 40-300. The instrumental set-up is such that both one-dimensional (GC-FID and GC-qMSD) and two-dimensional separations using the same working conditions can be performed. Gasoline and kerosene samples were analyzed on the column combination HP-5MS ((1)D)+HP INNOWax ((2)D). Three modulated peaks were obtained for each hydrocarbon present above 0.1% with ca. 300 ms peak width at the base using 6 s modulation times. Modulated peaks in GC × GC-FID were thus characterized by ca. 30 points while those in GC × GC-qMSD method by 6-8 points only. The FID speed is sufficient for reliable quantitative analysis, while the qMSD scan speed is perfectly appropriate for identification purposes. Moreover, in the GC × GC-qMSD method considerably improved quality of uncorrected spectra was obtained, arising from the enhanced separation over one-dimensional GC-MSD analysis. Spectral match qualities of up to 98% were found. PMID:23395547

Krup?ík, Ján; Gorovenko, Roman; Spánik, Ivan; Sandra, Pat; Armstrong, Daniel W

2013-03-01

188

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

USGS Publications Warehouse

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.

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

1999-01-01

189

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

PubMed

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

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

2014-02-01

190

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

NASA Astrophysics Data System (ADS)

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

Meydaneri, Fatma; Saatçi, Buket; Gündüz, Mehmet; Özdemir, Mehmet

2013-11-01

191

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

SciTech Connect

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

DeVol, T.A.; Fjeld, R.A.; Roane, J.E. [Clemson Univ., SC (United States). Dept. of Environmental Systems Engineering; Leyba, J.D. [Westinghouse Savannah River Co., Aiken, SC (United States); Branton, S.D. [Nuclear Regulatory Commission, Washington, DC (United States)

1996-12-31

192

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...

193

Profiling of oxidized phospholipids in lipoproteins from patients with coronary artery disease by hollow fiber flow field-flow fractionation and nanoflow liquid chromatography-tandem mass spectrometry.  

PubMed

Oxidized phospholipids (Ox-PLs) are oxidatively modified PLs that are produced during the oxidation of lipoproteins; oxidation of low density lipoproteins especially is known to be associated with the development of coronary artery disease (CAD). In this study, different lipoprotein classes (high density, low density, and very low density lipoproteins) from pooled plasma of CAD patients and pooled plasma from healthy controls were size-sorted on a semipreparative scale by multiplexed hollow fiber flow field-flow fractionation (MxHF5), and Ox-PLs that were extracted from each lipoprotein fraction were quantified by nanoflow liquid chromatography-tandem mass spectrometry (nLC-ESI-MS/MS). The present study showed that oxidation of lipoproteins occurred throughout all classes of lipoproteins with more Ox-PLs identified from CAD patient lipoproteins: molecular structures of 283 unique PL species (including 123 Ox-PLs) from controls and 315 (including 169 Ox-PLs) from patients were identified by data-dependent collision-induced dissociation experiments. It was shown that oxidation of PLs occurred primarily with hydroxylation of PL; in particular, a saturated acyl chain such as 16:0, 18:0, or even 18:1 at the sn-1 location of the glycerol backbone along with sn-2 acyl chains with at least two double bonds were identified. The acyl chain combinations commonly found for hydroxylated Ox-PLs in the lipoproteins of CAD patients were 16:0/18:2, 16:0/20:4, 18:0/18:2, and 18:0/20:4. PMID:25494038

Lee, Ju Yong; Byeon, Seul Kee; Moon, Myeong Hee

2015-01-20

194

Shear Flow Stabilization of a z-Pinch Plasma in the Presence of a Radial Temperature Gradient  

E-print Network

The previous study regarding the stabilization of a magnetized constant temperature plasma by shear flow with vorticity is extended to a plasma of non-constant temperature, where in the presence of heat source or sinks the thermomagnetic Nernst effect becomes important. Of special interest is what this effect has on the stabilization of a linear z-pinch discharge for which exact solutions are given.

Winterberg, F

2009-01-01

195

Continuous flow PCB radiolysis with real time assessment by gas chromatography  

SciTech Connect

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

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

2006-05-01

196

Separation of five oligostilbenes from Vitis amurensis by flow-rate gradient high-performance counter-current chromatography.  

PubMed

A rapid and efficient high-performance counter-current chromatography (HPCCC) method was developed to separate five oligostilbenes from the roots of Vitis amurensis. An n-hexane/ethyl acetate/methanol/water system (4:8:4:10, v/v/v/v) was selected as an optimal two-phase solvent system of which the upper phase was used as the stationary phase and the lower phase was used as the mobile one. Partition coefficient values for the target compounds under these optimized conditions were 0.28 (1, ampleosin A), 7.12 (2, (+)-g-viniferin), 2.26 (3, vitisin A), 5.38 (4, wilsonol C), and 11.23 (5, vitisin B). Flow-rate gradient HPCCC (4 mL/min in 0-70 min, 8 mL/min in 70-250 min) was applied to isolate the target compounds in as high purity as possible within the shortest possible run time. Under these conditions, ampelopsin A (12.1 mg), (+)-g-viniferin (10.4 mg), vitisin A (2.8 mg), wilsonol C (3.2 mg), and vitisin B (37 mg) were isolated with >95% purity from 150 mg of enriched oligostilbene extract. Although the KD of the last eluted compound, vitisin B (KD = 11.23), was relatively large, it was eluted in 115-145 min using the two-phase solvent system. This study shows that HPCCC is an efficient tool for the isolation and purification of natural products. PMID:24167107

Ko, Jaeyoung; Choi, Janggyoo; Bae, Soo Kyung; Kim, Jinwoong; Yoon, Kee Dong

2013-12-01

197

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)

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.

Katsanis, T.; Mcnally, W. D.

1977-01-01

198

Fast analysis of polyphenols in royal jelly products using automated TurboFlow™-liquid chromatography-Orbitrap high resolution mass spectrometry.  

PubMed

This study describes the development of a novel, simple and fast analytical method for the detection and quantification of polyphenols in royal jelly products, using an in-house database containing more than 50 compounds. The extraction method consisted of sample dilution, followed by a fast on-line system composed of turbulent flow chromatography (TurboFlow™) coupled to liquid chromatography (LC)-Exactive-Orbitrap analyzer. The total run time was 18min, including automated extraction, analytical chromatography and re-equilibration. The method was validated obtaining limits of quantification (LOQ) ranging from 10 to 150?g/kg. The linearity range was up to 2000?g/L and determination coefficients (R(2)) were higher than 0.994. Adequate recoveries were obtained at three concentration levels (500, 1000 and 2000?g/kg). This method was applied to the analysis of nine samples and the concentration of polyphenols ranged from 14 (apigenin) to 18,936?g/kg (ferulic acid). PMID:25464090

López-Gutiérrez, Noelia; Aguilera-Luiz, María Del Mar; Romero-González, Roberto; Vidal, José Luis Martínez; Garrido Frenich, Antonia

2014-10-21

199

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

SciTech Connect

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

Vilim, R. B. (Nuclear Engineering Division)

2012-07-31

200

Radial Erosion  

NASA Technical Reports Server (NTRS)

[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.

2005-01-01

201

Radial Inflow Turboexpander Redesign  

SciTech Connect

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

William G. Price

2001-09-24

202

Sweeping under controlled electroosmotic flow and micellar electrokinetic chromatography for on-line concentration and determination of trace phlorizin and quercitrin in urine samples.  

PubMed

A novel sweeping under controlled electroosmotic flow scheme was developed for preconcentration and determination of neutral compounds by micellar electrokinetic chromatography (MEKC). An anionic surfactant, sodium dodecyl sulfate (SDS), was added into the buffer for sweeping and separation. By controlled electroosmotic flow (EOF) equal to the counter electrophoretic flow, the surfactants were at an immobile state in capillary. The neutral analytes with sample solution was injected electroosmotically into capillary and swept by SDS micelle for essentially an unlimited volume. The injected sample plug lengths for phlorizin and quercitrin under 18 kV for 70 min were experimentally estimated as 1532 cm, corresponding to 51-fold the effective capillary length. The sweeping under controlled EOF scheme resulted in increased detection factors for phlorizin and quercitrin of 2.3 × 10? and 2.1 × 10? using 70 min injection relative to a traditional pressure injection. The proposed method has been adopted to analyze trace phlorizin and quercitrin in urine samples successfully. PMID:21664088

Zhang, Xiaowei; Zhang, Zhaoxiang

2011-09-10

203

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

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

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

2014-08-13

204

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

SciTech Connect

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.

R.V. Budny

2002-08-13

205

High performance liquid chromatography  

SciTech Connect

A broad-based, general book on high performance liquid chromatography, designed to be a standard in the field. Written by contributors who work at the cutting edge of the science, this text/reference provides chromatographers, and teachers and students of analytical chemistry with comprehensive coverage of the theoretical bases for HPLC. Contributions explain terminology, thermodynamics and kinetics, detectors and derivatization, stationary phases, separations, equipment, error analysis, and advanced techniques, such as supercritical fluid chromatography and field flow fractionation.

Brown, P.; Hartwick, R.A.

1988-01-01

206

Reverse radial forearm fascial flap with radial artery preservation.  

PubMed

The reverse radial forearm fascial (RRFF) flap is widely used in soft-tissue reconstruction of the hand. The traditional RRFF flap incorporates the radial artery from the forearm and is perfused by retrograde flow through the palmar arch. In patients with an abnormal Allen test because of an incomplete palmar arch, the traditional RRFF flap is contraindicated unless a vein graft is used to reconstruct the radial artery. A simpler alternative approach for hand reconstruction in such patients is a distally based RRFF flap based on radial artery perforators, which preserves the radial artery. We used RRFF flaps based on radial artery perforators in five patients who had palmar or dorsal soft-tissue loss. All five recovered full hand function, and only one had any complications (full-thickness skin graft loss at recipient site). The RRFF flap based on distal radial artery perforators is suitable for thin coverage of soft-tissue defects in hands with either a complete or an incomplete palmar arch. PMID:18780079

Hansen, Adam J; Duncan, Scott F M; Smith, Anthony A; Shin, Alexander Y; Moran, Steven L; Bishop, Allen T

2007-09-01

207

Radial inflow turbine study  

NASA Astrophysics Data System (ADS)

The radial inflow turbine is a primary component used both in small gas turbines and turbochargers. Better understanding of the flow processes occurring within the small passages of the machine could well result in the improved design of units. As most of the detailed aerodynamics is still ill-defined, a joint research project with the objective of improving our understanding has been instigated by Cranfield, the US Army and Turbomach (San Diego). This document gives the seventh report on the project and describes progress and measurements taken.

Hamid, S.; Elder, R. L.

1992-03-01

208

ION CHROMATOGRAPHY  

EPA Science Inventory

The theory of ion chromatography as a technique for analyzing ionic substances is discussed. The application of ion chromatography for analyzing ambient air samples is specifically described, with emphasis on determining sulfate, nitrate, and ammonium ions in aerosols, and sulfur...

209

Chromatography Theory  

NSDL National Science Digital Library

James Hardy has produced a number of presentation-style lecture modules for analytical chemistry. This is a very good module that covers the introductory theory of chromatography. The material includes information on chromatography along with plate and kinetic theories. It is a colorful and well planned presentation of the introduction to chromatography that could be used as the basis for lectures on chromatography at the introductory analytical chemistry or instrumental analysis level.

210

Affinity Chromatography  

NSDL National Science Digital Library

This is an experiment showing the application of affinity chromatography to the separation of albumin from horse serum. A brief introduction of affinity chromatography and how it is being used in this specific experiment is given. This appears to be a good experiment to show the advantages of affinity chromatography in separating specific proteins from a complex matrix and would be useful in a biochemistry course or a course that is specifically looking at differing types of chromatography.

DiResta, Dan

211

High-temperature liquid chromatography coupled on-line to a continuous-flow biochemical screening assay with electrospray ionization mass spectrometric detection.  

PubMed

The potential of high-temperature liquid chromatography (HTLC) was investigated in an on-line combination with a screening system for bioactive compounds against the enzyme cathepsin B. Samples were separated by HTLC and subsequently analyzed by an on-line continuous-flow enzymatic assay. Detection was performed by electrospray ionization mass spectrometry, revealing both the bioactivity and the molecular mass of the bioactive compounds. Compared to conventional reversed-phase liquid chromatography, the amount of methanol necessary for separation could be decreased to only 10%, which improved the compatibility of LC with a biochemical assay. Sufficient preheating of the mobile phase prior to the separation and postcolumn cooling to prevent deactivation of the enzyme, even at column temperatures as high as 208 degrees C, was achieved as indicated by the reliable peak shapes obtained. The sensitivity was comparable with previously described systems operating at ambient temperatures as similar IC50 values were obtained. Exposing the inhibitors to high temperatures did not lead to thermal decomposition. The separation of inhibitors and the subsequent biochemical assay was performed either isothermally at various temperatures or by applying various temperature gradients as well as at various flow rates. The results obtained clearly show the compatibility of HTLC with an enzymatic screening assay. PMID:16351135

de Boer, Arjen R; Alcaide-Hidalgo, Juan M; Krabbe, Johannes G; Kolkman, Jeffrey; van Emde Boas, Caspar N; Niessen, Wilfried M A; Lingeman, Henk; Irth, Hubertus

2005-12-15

212

Neuere Chromatographie  

NASA Astrophysics Data System (ADS)

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.

Hostettmann, K.

1983-04-01

213

Radial cold trap  

DOEpatents

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.

Grundy, Brian R. (Greensburg, PA)

1981-01-01

214

Radial cold trap  

DOEpatents

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.

Grundy, B.R.

1981-09-29

215

CALIBRATION OF SUBMERGED RADIAL GATES  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

216

Chemical evolution with radial mixing  

Microsoft Academic Search

Models of the chemical evolution of our Galaxy are extended to include radial migration of stars and flow of gas through the disc. The models track the production of both iron and alpha-elements. A model is chosen that provides an excellent fit to the metallicity distribution of stars in the Geneva-Copenhagen survey (GCS) of the solar neighbourhood and a good

Ralph Schönrich; James Binney

2009-01-01

217

Radially-Graduated Turbine-Temperature Profile  

NASA Technical Reports Server (NTRS)

Proposed scheme to change temperature distribution in gas-turbine flame increases radially instead of remaining spatially uniform offers important advantages. Radially increasing temperature allows higher mean gas temperature, greater power output, higher rotational speed and longer life for blades. Principle suitable for axial-flow gas turbine directly in line with cylindrical combustor. Included in category many rocket, aircraft, stationary, and shipboard turbines.

Wagner, W. R.; Nitz, F. P.; Strangeland, M. L.

1984-01-01

218

Losses in radial inflow turbines  

NASA Technical Reports Server (NTRS)

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.

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

1976-01-01

219

CHROMATOGRAPHY A ELSEVIER Journal of Chromatography A, 662 (1994) 369-373  

E-print Network

JOURNAL OF CHROMATOGRAPHY A ELSEVIER Journal of Chromatography A, 662 (1994) 369-373 Determination and electroosmotic flow of polytetrafluoroethylene (PTFE) capil- laries was measured. A number of papers have been

Miksik, Ivan

220

On radial geodesic forcing of zonal modes  

SciTech Connect

The elementary local and global influence of geodesic field line curvature on radial dispersion of zonal modes in magnetised plasmas is analysed with a primitive drift wave turbulence model. A net radial geodesic forcing of zonal flows and geodesic acoustic modes can not be expected in any closed toroidal magnetic confinement configuration, since the flux surface average of geodesic curvature identically vanishes. Radial motion of poloidally elongated zonal jets may occur in the presence of geodesic acoustic mode activity. Phenomenologically a radial propagation of zonal modes shows some characteristics of a classical analogon to second sound in quantum condensates.

Kendl, A. [Institute for Ion Physics and Applied Physics, Association Euratom-OeAW, University of Innsbruck, A-6020 Innsbruck (Austria)

2011-07-15

221

NASA contributions to radial turbine aerodynamic analyses  

NASA Technical Reports Server (NTRS)

A brief description of the radial turbine and its analysis needs is followed by discussions of five analytical areas; design geometry and performance, off design performance, blade row flow, scroll flow, and duct flow. The functions of the programs, areas of applicability, and limitations and uncertainties are emphasized. Both past contributions and current activities are discussed.

Glassman, A. J.

1980-01-01

222

Affinity Chromatography GST-tagged Proteins  

E-print Network

Affinity Chromatography GST-tagged Proteins His-tagged Proteins Antibody Immobilization Nucleotide binding Proteins Phospho-Aminoacid binding Proteins www.jenabioscience.com #12;Table of Contents AffinityChromatography Affinity Chromatography 3 GST-tagged Proteins 4 Glutathione ChroMatrixTM, Fast Flow 4 GST Cleavage Capture

Lebendiker, Mario

223

Column Chromatography  

NSDL National Science Digital Library

In this activity, learners separate the components of Gatorade using a home-made affinity column. In doing so, learners model the basic principle of affinity chromatography, a technique used to purify chemicals as well as bio-pharmaceuticals and petroleum products. This resource contains information about affinity chromatography and polarity.

Julie Yu

2007-01-01

224

Chromatography Theory  

NSDL National Science Digital Library

This site contains standard definitions related to chromatography similar to treatments found in analytical chemistry textbooks. It introduces the beginning student to Liquid Chromatography concepts relevant to biochemistry and includes a good example of choosing a mobile phase pH for a protein separation based on ion exchange.

225

Gas Chromatography.  

ERIC Educational Resources Information Center

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…

Karasek, Francis W.; And Others

1984-01-01

226

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

PubMed

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. PMID:25766495

Schwienheer, C; Merz, J; Schembecker, G

2015-04-17

227

Numerical simulation of a radial diffuser turbulent airflow  

Microsoft Academic Search

In the present work are presented results from numerical simulations performed with the ANSYS-CFX® code. We have studied a radial diffuser flow case, which is the main academic problem used to study the flow behavior on flat plate valves. The radial flow inside the diffuser has important behavior such as the turbulence decay downstream and recirculation regions inside the valve

Alysson Kennerly Colaciti; Luis Miguel Valdés López; Hélio Aparecido Navarro; Luben Cabezas-gómez

2007-01-01

228

Dielectrokinetic chromatography devices  

DOEpatents

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.

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

2014-12-16

229

Chromatography 50 Chem 355 Jasperse Chromatography  

E-print Network

Chromatography 50 Chem 355 Jasperse Chromatography BACKGROUND Chromatography is a powerful. Advantages for chromatography are its power and generality (not limited to liquids or solids or the need. Chromatography Every type of chromatography depends on the distribution of a substance between two phases

Jasperse, Craig P.

230

Radial Artery Catheterization  

MedlinePLUS

... Name Password Sign In Cardiology Patient Page Radial Artery Catheterization Nicholas R. Balaji , MD ; Pinak B. Shah , ... procedures. Previous Section Next Section Advantages of Radial Artery Catheterization Any catheter placement into a blood vessel ...

231

Radial head fracture - aftercare  

MedlinePLUS

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

232

Toroidal coil counter-current chromatography. Achievement of high resolution by optimizing flow-rate, rotation speed, sample volume and tube length.  

PubMed

This paper deals with optimization of a new seal-free compact toroidal coil centrifuge to achieve high resolution in analytical counter-current chromatography (CCC). Toroidal coil CCC (hydrostatic motion) has advantages compared with high-speed CCC (efficiently mixing solution with planetary motion) in the separation of protein or easily emulsified samples. A toroidal coil separation column of 0.4 mm I.D. PTFE tubing was accommodated around the periphery of the cylindrical centrifuge bowl. Using a two-phase solvent system composed of chloroform-acetic acid-0.1 M hydrochloric acid (2:2:1, v/v/v) and a set of dinitrophenyl-amino acids as test samples, a series of experiments was performed with parameters such as the column length, sample volume, flow-rate, elution mode of the mobile phase and rotation speed. The highest efficiency, over 10,000 theoretical plates, was achieved with a 100 m long coiled tube and an 11 ml total capacity at a flow-rate of 0.01 ml/min at 800 rpm. PMID:9652111

Matsuda, K; Matsuda, S; Ito, Y

1998-05-29

233

Fast protein liquid chromatography.  

PubMed

Fast protein liquid chromatography (FPLC) is a form of high-performance chromatography that takes advantage of high resolution made possible by small-diameter stationary phases. It was originally developed for proteins and features high loading capacity, biocompatible aqueous buffer systems, fast flow rates, and availability of stationary phases in most common chromatography modes (e.g., ion exchange, gel filtration, reversed phase, and affinity). The system makes reproducible separation possible by incorporating a high level of automation including autosamplers, gradient program control, and peak collection. In addition to proteins, the method is applicable to other kinds of biological samples including oligonucleotides and plasmids. The most common type of FPLC experiment is anion exchange of proteins. This chapter describes such an experiment carried out using an ÄKTA FPLC explorer system (Amersham Pharmacia Biotech, Sweden). PMID:20978981

Madadlou, Ashkan; O'Sullivan, Siobhan; Sheehan, David

2011-01-01

234

Management of radial dysplasia.  

PubMed

An appreciation of the clinicopathologic presentation of children with radial dysplasia (radial club hand) is important. Management decisions depend upon the degree of radial ray defect present; in most cases these are surgical. Current surgical options favor centralization without resection of carpal bones, stabilized by tendon transfers. When the thumb ray is deficient, pollicization is a rewarding procedure. PMID:2269674

Urban, M A; Osterman, A L

1990-11-01

235

Exclusion Chromatography  

NSDL National Science Digital Library

This site contains a brief description of the separation mechanism in size exclusion chromatography. The picture helps visualize the separation, but the site features a simplified and idealized presentation useful for students new to the concept.

Kimball, John W.

236

Gas Chromatography  

NSDL National Science Digital Library

This is a website from the US Environmental Protection Agency that explains Gas Chromatography for those interested in environmental analysis. The level of the material assumes some user background in the field.

237

Gas Chromatography.  

ERIC Educational Resources Information Center

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)

Cram, Stuart P.; And Others

1980-01-01

238

Affinity Chromatography  

NSDL National Science Digital Library

Using exposition, graphics, and commercial videos, this module teaches the theory and application of affinity chromatography in the characterization of proteins, nucleic acids, and other biochemical/biomedical systems. Problems and application examples support the tutorial material.

239

Novel Integrated Radial and Axial Magnetic Bearing  

NASA Technical Reports Server (NTRS)

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

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

2000-01-01

240

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

SciTech Connect

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.

Takada, Michiya [Division of Diabetes, Metabolism and Endocrinology, Department of Internal Medicine, Showa University School of Medicine, Tokyo (Japan)] [Division of Diabetes, Metabolism and Endocrinology, Department of Internal Medicine, Showa University School of Medicine, Tokyo (Japan); Ban, Yoshiyuki, E-mail: yshyban@yahoo.co.jp [Division of Diabetes, Metabolism and Endocrinology, Department of Internal Medicine, Showa University School of Medicine, Tokyo (Japan)] [Division of Diabetes, Metabolism and Endocrinology, Department of Internal Medicine, Showa University School of Medicine, Tokyo (Japan); Yamamoto, Gou [Department of Oral Pathology and Diagnosis, School of Dentistry, Showa University, Tokyo (Japan)] [Department of Oral Pathology and Diagnosis, School of Dentistry, Showa University, Tokyo (Japan); Ueda, Toshihiko; Saito, Yuta; Nishimura, Eiichi; Fujisawa, Kunimi; Koide, Ryohei [Department of Ophthalmology, Showa University School of Medicine, Tokyo (Japan)] [Department of Ophthalmology, Showa University School of Medicine, Tokyo (Japan); Mizutani, Masakazu; Kozawa, Tadahiko; Shiraishi, Yuji [Kozawa Eye Hospital and Diabetes Center, Ibaraki-ken (Japan)] [Kozawa Eye Hospital and Diabetes Center, Ibaraki-ken (Japan); Bando, Yasuhiko [Biosys Technologies, Inc., Meguro, Tokyo (Japan)] [Biosys Technologies, Inc., Meguro, Tokyo (Japan); Tachikawa, Tetsuhiko [Department of Oral Pathology and Diagnosis, School of Dentistry, Showa University, Tokyo (Japan)] [Department of Oral Pathology and Diagnosis, School of Dentistry, Showa University, Tokyo (Japan); Hirano, Tsutomu [Division of Diabetes, Metabolism and Endocrinology, Department of Internal Medicine, Showa University School of Medicine, Tokyo (Japan)] [Division of Diabetes, Metabolism and Endocrinology, Department of Internal Medicine, Showa University School of Medicine, Tokyo (Japan)

2010-08-20

241

High-Performance Liquid Chromatography  

NASA Astrophysics Data System (ADS)

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.

Reuhs, Bradley L.; Rounds, Mary Ann

242

Chemiluminescence detectors for liquid chromatography.  

PubMed

In this tutorial we describe the construction of chemiluminescence detectors for high performance liquid chromatography (HPLC), comprising the components required to deliver the chemiluminescence reagent, a coiled-tubing flow cell, photomultiplier tube and detector housing, and various options for data acquisition. We also discuss two state-of-the-art commercially available chemiluminescence detectors for HPLC and other flow analysis methodology. PMID:21425470

Adcock, Jacqui L; Terry, Jessica M; Barrow, Colin J; Barnett, Neil W; Olson, Don C; Francis, Paul S

2011-03-01

243

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

PubMed Central

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

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

2013-01-01

244

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

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…

Blanck, Harvey F.

2012-01-01

245

Analysis of cocaine and benzoylecgonine in urine by using multisyringe flow injection analysis-gas chromatography-mass spectrometry system.  

PubMed

In this paper, a method was described to determine cocaine (COC) and benzoylecgonine (BZE) in human urine samples by GC-MS detection. The extraction of analytes from urine samples was achieved in an Oasis hydrophilic-lipophilic balance column (20 mmx3.9 mm id, dp=25 microm; Waters, USA), incorporated in a multisyringe flow injection system, used for the sample treatment. Finally, to improve the volatility of the BZE, an in-line derivatization reaction with N,O-bis (trimethylsilyl) trifluoroacetamide with 1% trimethylchlorosilane was made microwave-assisted in order to reduce the reaction time. The results showed that the proposed method is a good alternative for the analysis of COC and BZE in urine samples because it offers advantages compared with those described in the literature, which include simplicity in the sample treatment, the sensitivity and selectivity necessary to determine the analytes of interest at low levels in the urine and high sample throughput. PMID:20491055

Brunetto, María del Rosario; Delgado, Yelitza; Clavijo, Sabrina; Contreras, Yaritza; Torres, Dina; Ayala, Carlos; Gallignani, Máximo; Forteza, Rafael; Cerdà Martin, Víctor

2010-06-01

246

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

PubMed

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 (1-100mg/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?g/L (for the C1-benzothiophene class), while the lowest was 21?g/L (for the C4-benzothiophene class). PMID:25704775

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

2015-03-27

247

Validation and application of micro flow liquid chromatography-tandem mass spectrometry for the determination of pesticide residues in fruit jams.  

PubMed

In this study, a very sensitive method was validated to determine pesticides residues in fruit jams using micro flow liquid chromatography-tandem mass spectrometry (µLC-MS/MS). A slurry of the fruit jams and water was prepared to yield homogeneous samples. Because of the high sensitivity achieved with the µLC-MS/MS equipment and to minimize matrix effects, the QuEChERS extracts were diluted 30-fold before the analysis. The validation was performed analyzing spiked samples at 9 and 45 µg kg(-1) (n=5). The method met validation criteria of 70-120% recovery and RSD?20% for 92% of the 107 pesticides evaluated. The reporting limit (RL) was 9 and 45 µg kg(-1) for respectively 66% and 26% of the analytes, 5% of the compounds did not fulfill the requirements for validation and 3% were not detected at the studied concentrations. The validated method was applied to the analysis of 51 different fruit jam samples from Brazil and Spain and pesticide residues were detected in 41 samples, 26 of which contained at least one pesticide at concentration >10 µg kg(-1). PMID:25618688

Reichert, Bárbara; Pizzutti, Ionara Regina; Costabeber, Ijoni Hilda; Uclés, Ana; Herrera, Sonia; Fernández-Alba, Amadeo R

2015-03-01

248

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

PubMed

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

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

2015-04-15

249

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

SciTech Connect

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

Hunger, M.; Horvath, T. [Univ of Stuttgart (Germany)] [Univ of Stuttgart (Germany)

1997-04-01

250

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

PubMed

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

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

2012-03-01

251

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

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

252

Radial arm strike rail  

DOEpatents

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.

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

1991-01-01

253

Gas Chromatography  

NSDL National Science Digital Library

This site contains a brief introduction to the concepts of injection and detection in gas chromatography, focusing on the split/splitless injection port and flame ionization detectors. The treatment is similar to that in analytical chemistry textbooks, and includes detailed illustrations.

254

Spotting Chromatography  

NSDL National Science Digital Library

In this mini-lab students will use chromatography to compare the mobile phase and the stationary phases of different inks used in marking pens. They will also determine the polarity of the solvents and inks. Finally, the students will use their calculated information to solve a crime.

255

Paper Chromatography  

NSDL National Science Digital Library

This is a site with experiments that provide a brief introduction to the idea of separation of components in a mixture and a set of instructions for students for separating colored compounds by paper chromatography (on coffee filters). The appropriate audience would be students in a high-school or introductory, non major college chemistry class.

Reeves, James H.

2011-05-19

256

Ion chromatography  

Microsoft Academic Search

Ion chromatography makes it possible to separate and measure low concentrations of up to 8 or 10 different anions in a single chromatographic run that takes only a few minutes. The method also works well for cations. Alkali metal ions, ammonium, magnesium, calcium, strontium, and a growing list of other metal cations and amine cations can also be rapidly separated

James S. Fritz

1987-01-01

257

Data reduction problems using a 3-hole directional pressure probe to investigate mean flow characteristics in the vaneless gap between impeller and diffuser radial pump  

NASA Astrophysics Data System (ADS)

Among several different measurement techniques that have been already performed and presented in a radial impeller pump model including PIV, a directional pressure probe has been used to obtain mean velocity field and stagnation pressure between impeller outlet and the inlet vaned diffuser sections. These measurements are supposed to get more information not only about global pump head coefficient including vaned diffuser ones but also about impeller performances itself. Pressure probe information is affected by rotor-stator interactions and impeller rotation, and this paper presents a way to explain and correct pressure probe indications in order to achieve a better evaluation of overall impeller mean performances. The use of unsteady RANS calculation results is found to be a useful way to perform better data reduction analysis for this purpose.

Cherdieu, P.; Dupont, P.; Bayeul-Lainé, A. C.; Dazin, A.; Bois, G.

2013-12-01

258

Triple acting radial seal  

DOEpatents

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.

Ebert, Todd A (West Palm Beach, FL); Carella, John A (Jupiter, FL)

2012-03-13

259

Effects of chain decays, radial flow and $U_{A}(1)$ restoration on the low-mass dilepton enhancement in $\\sqrt{s_{NN}}=200$ GeV Au+Au reactions  

E-print Network

In sqrt(sNN) = 200 GeV Au+Au collisions PHENIX reported a significant enhancement in the low-mass region (0.1 < m_ee < 0.7 GeV) of the dielectron spectrum, which is still not fully understood. Several theoretical works and an indirect measurement suggest that, due to the possible restoration of the U_A(1) part of the chiral symmetry in a hot and dense medium, the mass of the eta' meson may substantially decrease. This work reports on a statistically acceptable description of the PHENIX low-mass dilepton enhancement using a radial flow dominated meson spectra, chain decays of long-lived resonances and an in-medium eta' mass modification.

Marton Vargyas; Robert Vertesi; Tamas Csorgo

2013-05-22

260

Spiral Countercurrent Chromatography  

PubMed Central

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

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

2013-01-01

261

Spiral countercurrent chromatography.  

PubMed

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

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

2013-08-01

262

Chromatography Lab  

NSDL National Science Digital Library

To increase students' awareness of possible invisible pollutants in drinking water sources, students perform an exciting lab requiring them to think about how solutions and mixtures exist even in unsuspecting places such as ink. They use alcohol and chromatography paper to separate the components of black and colored marker ink. Students witness first-hand how components of a solution can be separated, even when those individual components are not visible in solution.

2014-09-18

263

[Reconstruction of through and through gunshot injuries of the hand with a double skin paddle reverse-flow forearm radial flap. Two case reports].  

PubMed

The authors report two cases of gunshot wounds to the hand treated with a double skin paddle reverse-flow forearm flap. The two cases, male and female, were due to a self-inflicted rifle injury. The wounds were severe and extensive with full-thickness palmar and dorsal skin, tendon, muscle, bone, vessel and nerve losses. Treatment was performed in a single stage with skeletal stabilization, bone grafting and nerve and tendon reconstruction. The double palmar and dorsal skin defect was reconstructed with a double skin paddle reverse-flow forearm flap which was routed through the hand wound. The forearm flap is the sole way, free flaps excepted, to achieve reliable hand dorsal and palmar coverage in a single stage. In addition, this technique simplifies the reconstruction by using a local flap and allows better management for healing and rehabilitation as compared to a multiple flap procedure. PMID:17855143

Philandrianos, C; Guinard, D; Legré, R

2007-01-01

264

Radial heat flux transformer  

NASA Technical Reports Server (NTRS)

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.

Basiulis, A.; Buzzard, R. J.

1971-01-01

265

Screened hydrogenic radial integrals  

NASA Technical Reports Server (NTRS)

The screened hydrogenic radial integral for discrete-discrete and discrete-continuum transitions is expressed in forms suitable for obtaining closed-form expressions for specific transitions. Two effective-charge parameters, for the initial state and for the final state, are retained in these formulas. As examples, explicit expressions for a few transitions are derived, and a method for obtaining a series for a discrete-discrete radial integral, suitable for large final-state principal quantum numbers, is indicated.

Khandelwal, G. S.; Pritchard, W. M.; Grubb, G.; Khan, F.

1989-01-01

266

Molecular size and mass distributions of native starches using complementary separation methods: asymmetrical flow field flow fractionation (A4F) and hydrodynamic and size exclusion chromatography (HDC-SEC).  

PubMed

Starch consists of a mixture of two ?-glucans built mainly upon ?-(1,4) linkages: amylose, an essentially linear polymer, and amylopectin, a branched polymer containing 5-6% of ?-(1,6) linkages. The aim of the present work was to analyze the structural properties of native starches displaying different amylose-to-amylopectin ratios and arising from different botanical sources, using asymmetrical flow field flow fractionation (A4F) and a combination of hydrodynamic and size-exclusion chromatography (HDC-SEC) coupled with multiangle laser light scattering, online quasi-elastic light scattering, and differential refractive index techniques. The procedure, based upon dimethyl sulfoxide pretreatment and then solubilization in water, generates a representative injected sample without altering the initial degree of polymerization. The amylopectin weight-average molar masses and radii of gyration were around 1.0 × 10(8)-4.8 × 10(8) g mol(-1) and 110-267 nm, respectively. For each starch sample, the hydrodynamic radius (R(H)) distributions and the molar mass distributions obtained from the two fractionation systems coupled with light scattering techniques were analyzed. The size determination scales were extended by means of R(H) calibration curves. HDC-SEC and A4F data could be matched. However, A4F enabled a better separation of amylopectins and therefore an enhanced structural characterization of the starches. The two advantages of this experimental approach are (1) it can directly obtain distributions as a function of both molar mass and size, while taking account of sample heterogeneity, and (2) it is possible to compare the results obtained using the different techniques through the direct application of R(H) distributions. PMID:20878394

Rolland-Sabaté, Agnès; Guilois, Sophie; Jaillais, Benoît; Colonna, Paul

2011-02-01

267

Gas Chromatography  

NSDL National Science Digital Library

The North Carolina Community College System BioNetwork's interactive eLearning tools (IETs) are reusable chunks of training that can be deployed in a variety of courses or training programs. IETs are designed to enhance, not replace hands-on training. Learners are able to enter a hands-on lab experience better prepared and more confident. This particular IET delves into gas chromatography and its application in discovering the amount of pesticide in fruit.Flash player is required to view and participate in this interactive learning unit.

268

A new physical model based on cascading column experiments to reproduce the radial flow and transport of micro-iron particles  

NASA Astrophysics Data System (ADS)

In the field of aquifer restoration and civil engineering, fluids and suspensions are delivered in porous media via well injection. The flow field resulting around the well is three-dimensional. Since two and three-dimensional experiments which can be used to reproduce such flow fields are, although accurate, extremely elaborate and time consuming, the authors suggest to substitute them by a cascade of interdependent, one-dimensional (column) experiments. The new method is used to simulate the injection in aquifers of micro-iron particles dispersed in a shear thinning gel of guar gum and allows the prediction of iron particle distribution around the well and of injection pressure. The method respects the mass balance at the field scale and its predictions are in good agreement with those of a mathematical model proposed in the literature. The method is consistent with the Triad Approach, a way to improve remediation efficiency proposed by the U.S. Environmental Protection Agency. The representativeness of the proposed tests combined with their simplicity and relative inexpensiveness make this new method applicable and useful in the planning and design of real remediation.

Comba, Silvia; Braun, Jürgen

2012-10-01

269

Anomalous roughening of forced radial imbibition in a porous medium  

E-print Network

We report forced radial imbibition of water in a porous medium in a Hele-Shaw cell. Washburn's law is confirmed in our experiment. Radial imbibition follows scaling dynamics and shows anomalous roughening dynamics when the front invades the porous medium. The roughening dynamics depend on the flow rate of the injected fluid. The growth exponents increase linearly with an increase in the flow rate while the roughness exponents decrease with an increase in the flow rate. Roughening dynamics of radial imbibition is markedly different from one dimensional imbibition with a planar interface window. Such difference caused by geometric change suggests that "universality class" for the interface growth is not universal.

Chen, Yong-Jun; Yoshikawa, Kenichi

2015-01-01

270

Anomalous roughening of forced radial imbibition in a porous medium  

E-print Network

We report forced radial imbibition of water in a porous medium in a Hele-Shaw cell. Washburn's law is confirmed in our experiment. Radial imbibition follows scaling dynamics and shows anomalous roughening dynamics when the front invades the porous medium. The roughening dynamics depend on the flow rate of the injected fluid. The growth exponents increase linearly with an increase in the flow rate while the roughness exponents decrease with an increase in the flow rate. Roughening dynamics of radial imbibition is markedly different from one dimensional imbibition with a planar interface window. Such difference caused by geometric change suggests that "universality class" for the interface growth is not universal.

Yong-Jun Chen; Shun Watanabe; Kenichi Yoshikawa

2015-03-13

271

Fundamentals of preparative and nonlinear chromatography  

SciTech Connect

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.

Guiochon, Georges A [ORNL; Felinger, Attila [ORNL; Katti, Anita [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Shirazi, Dean G [unknown

2006-02-01

272

Gas Chromatography  

NASA Astrophysics Data System (ADS)

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.

Qian, Michael C.

273

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

PubMed

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 ?g 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 ?g mL(-1)) and by the Directive 2004/19/EC (0.6 ?g 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 exception. The migrated amount, above the regulatory limits, was detected by all the mentioned assays. PMID:24223419

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

2014-01-01

274

Atomic Force Microscope Mediated Chromatography  

NASA Technical Reports Server (NTRS)

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

Anderson, Mark S.

2013-01-01

275

Dielectrokinetic chromatography and devices thereof  

DOEpatents

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.

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

2014-04-22

276

Gas Chromatography  

NSDL National Science Digital Library

This video, distributed on YouTube by the Royal Society of Chemistry, is on the basic principles of Gas Chromatography. This video is a short primer which introduces the technique and instrumentation. There are many assumptions that are made in the presentation of this material, due to the fact the video is meant to be a basic introduction. The ultimate strength of this video is the general nature of the content that makes it appealing to a wide audience. The video may be most appropriate in a lower-level general education science course (i.e forensic science) or as a quick orientation video for instrumental analysis students. The GC-FID and GC-MS are highlighted. Running time for the video is 5:17.

277

Radial transfer effects for poloidal rotation  

NASA Astrophysics Data System (ADS)

Radial transfer of energy or momentum is the principal agent responsible for radial structures of Geodesic Acoustic Modes (GAMs) or stationary Zonal Flows (ZF) generated by the turbulence. For the GAM, following a physical approach, it is possible to find useful expressions for the individual components of the Poynting flux or radial group velocity allowing predictions where a mathematical full analysis is unfeasible. Striking differences between up-down symmetric flux surfaces and asymmetric ones have been found. For divertor geometries, e.g., the direction of the propagation depends on the sign of the ion grad-B drift with respect to the X-point, reminiscent of a sensitive determinant of the H-mode threshold. In nonlocal turbulence computations it becomes obvious that the linear energy transfer terms can be completely overwhelmed by the action of the turbulence. In contrast, stationary ZFs are governed by the turbulent radial transfer of momentum. For sufficiently large systems, the Reynolds stress becomes a deterministic functional of the flows, which can be empirically determined from the stress response in computational turbulence studies. The functional allows predictions even on flow/turbulence states not readily obtainable from small amplitude noise, such as certain transport bifurcations or meta-stable states.

Hallatschek, Klaus

2010-11-01

278

Radial wedge flange clamp  

DOEpatents

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.

Smith, Karl H. (Yorktown, VA)

2002-01-01

279

Atomic force microscope mediated chromatography  

NASA Astrophysics Data System (ADS)

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

Anderson, M. S.

2013-02-01

280

Distally based radial forearm flap with preservation of the radial artery: anatomic, experimental, and clinical studies.  

PubMed

In this article we report on the anatomical, experimental, and clinical investigations of the distally adipofascial pedicled radial forearm flap based on the small perforators around the radial styloid process. There are about 10 small perforators (0.3-0.5 mm in diameter) from the distal radial artery around the radial styloid process. The longitudinal chain-linked vascular plexuses (suprafascial, paraneural, and perivenous) formed by the forearm ascending and descending branches of septofasciocutaneous perforators meet and cross over with the transverse carpal vascular plexuses around the radial styloid region. Based on these directional-oriented plexuses, distally based adipofascial pedicled radial forearm fasciocutaneous and adipofascial flaps were designed and successfully applied in 34 clinical cases. The pivot point was located at 1-2 cm above the radial styloid. The skin island plus adipofascial pedicle measured between 9-18 cm in length, with the adipofascial pedicle 3-4 cm in width. The length-to-width ratio is 3-5:1. The venous drainage of this distally based flap was investigated anatomically and experimentally. The cephalic vein has no positive role for venous drainage in distally based flaps. The difference between distally based flaps and reverse-flow flaps, clinical selection of fasciocutaneous and adipofascial flaps, advantages and disadvantages, and technical tips for operative success are discussed. PMID:12942523

Chang, Shi-Min; Hou, Chun-Lin; Zhang, Feng; Lineaweaver, William C; Chen, Zhong-Wei; Gu, Yu-Dong

2003-01-01

281

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

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

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

2013-01-01

282

Principles and Methods Chromatography  

E-print Network

Edition AC 18-1022-29 Principles and Methods Affinity Chromatography #12;Antibody Purification-1142-75 Protein Purification Handbook 18-1132-29 Ion Exchange Chromatography Principles and Methods 18-1114-21 Affinity Chromatography Principles and Methods 18-1022-29 Hydrophobic Interaction Chromatography Principles

Lebendiker, Mario

283

Radial Halbach Magnetic Bearings  

NASA Technical Reports Server (NTRS)

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

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

2009-01-01

284

Navier-Stokes analysis of radial turbine rotor performance  

NASA Technical Reports Server (NTRS)

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.

Larosiliere, L. M.

1993-01-01

285

LC-LC, Low Cost Liquid Chromatography. II. In-Line Flow-Preparation of Eluents of Fixed pHs  

Microsoft Academic Search

Conventional preparation of the weak aqueous eluent for reversed phase liquid chromatography by weighing, pipeting, and\\/or titrating materials can be time consuming, poorly reproducible, and require storage of many containers of final buffer. Stored buffers can become contaminated by vapors, container-leached materials, or microbes.This paper discribes a novel approach for preparing eluents in which LC-grade water is drawn through lengths

Vern Berry; Victor Pretorius

1990-01-01

286

Variable stator radial turbine  

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

287

Improved Lattice Radial Quantization  

E-print Network

Lattice radial quantization was proposed in a recent paper by Brower, Fleming and Neuberger[1] as a nonperturbative method especially suited to numerically solve Euclidean conformal field theories. The lessons learned from the lattice radial quantization of the 3D Ising model on a longitudinal cylinder with 2D Icosahedral cross-section suggested the need for an improved discretization. We consider here the use of the Finite Element Methods(FEM) to descretize the universally-equivalent $\\phi^4$ Lagrangian on $\\mathbb R \\times \\mathbb S^2$. It is argued that this lattice regularization will approach the exact conformal theory at the Wilson-Fisher fixed point in the continuum. Numerical tests are underway to support this conjecture.

Richard C. Brower; Michael Cheng; George T. Fleming

2014-07-28

288

Radial pressure flange seal  

DOEpatents

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.

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

1989-01-24

289

Radial pressure flange seal  

DOEpatents

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.

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

1989-01-01

290

Radial Field Piezoelectric Diaphragms  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

291

3D Velocity from 3D Doppler Radial Velocity J. L. Barron,1  

E-print Network

to compute local 3D velocity (local 3D optical flow). Radial velocity (measured by the Doppler effect3D Velocity from 3D Doppler Radial Velocity J. L. Barron,1 R. E. Mercer,1 X. Chen,1 P. Joe2 1 by a Doppler radar. We demonstrate the perfor- mance of our algorithms quantitatively on synthetic radial

Barron, John

292

[The radial (Chinese) flap in hand surgery].  

PubMed

The radial (Chinese) flap is an fascio-cutaneous flap raised on the volar aspect of the forearm based on the radial pedicle axis which can be used either pedicled or by microsurgical free transfer. In hand and thumb reconstruction, it is used as an island flap vascularized by a reverse flow from the ulnar artery via the palmar arch, keeping the pivot point at the snuff box level. The possibility to raise a composite flap with vascularized bone or tendons make the chinese flap very useful in hand reconstruction. Of the 35 cases presented, there were 30 pedicled and 5 free flaps from the opposite forearm. The island flaps were reverse flow in 30 cases and with proximal pedicle in 5. In 4 cases the flap contained flexor carpi radialis longus tendon, and in 2 cases a bone graft from the radius. The five free radial flaps transferred from the contralateral side were used as flow-through flap. There were no vascular complications. The advantages and disadvantages of the methods are discussed. PMID:15688768

Stamate, T; Budurc?, A R; Laz?r, A N

2004-01-01

293

The ARCS radial collimator  

NASA Astrophysics Data System (ADS)

We have designed, installed, and commissioned a scattered beam radial collimator for use at the ARCS Wide Angular Range Chopper Spectrometer at the Spallation Neutron Source. The collimator has been designed to work effectively for thermal and epithermal neutrons and with a range of sample environments. Other design considerations include the accommodation of working within a high vacuum environment and having the ability to quickly install and remove the collimator from the scattered beam. We present here characterization of the collimator's performance and methodologies for its effective use.

Stone, M. B.; Niedziela, J. L.; Overbay, M. A.; Abernathy, D. L.

2015-01-01

294

Radial cutting torch  

SciTech Connect

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

Robertson, M.C.

1997-01-08

295

Harvesting the radial artery  

PubMed Central

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

Osterday, Robert M.; Brodman, Richard F.

2013-01-01

296

Applying Simple Chromatography  

NSDL National Science Digital Library

This activity involves chemistry, mystery, colors, and measurement. Students observe the composition of various inks by separating them via water-based chromatography. Students use what they learn about chromatography to solve a mystery involving a suspic

John Eichinger

2009-05-15

297

Posttraumatic radial club hand.  

PubMed

Fifteen adult patients with an unstable ununited fracture of the distal third of the radius and severe radial deviation deformity resembling a radial club hand were retrospectively reviewed at an average of 25 months after operative treatment. There were eight women and seven men with an average age of 57 years (range, 33-79 years). The average duration of nonunion was 56 months (range, 6-252 months). Six patients had a concomitant fracture of the ulna and four had dislocation of the distal radioulnar joint. Three patients were treated with wrist arthrodesis and 12 with plate fixation and autogenous bone grafting. The distal ulna was excised and used for bone graft in eight patients. Correction of deformity was facilitated by z-lengthening of the brachioradialis and flexor carpal radialis in four patients and distraction histogenesis (llizarov) in two patients. One patient failed to heal the fracture and was treated with wrist arthrodesis. Functional alignment and use of the hand was restored in all patients. PMID:15559692

Ring, David; Prommersberger, Karl; Jupiter, Jesse B

2004-01-01

298

Radial reflection diffraction tomography  

NASA Astrophysics Data System (ADS)

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

Lehman, Sean K.; Norton, Stephen J.

2004-10-01

299

Innervated radial thenar flap for sensory reconstruction of fingers.  

PubMed

A radial thenar flap, which is supplied by the superficial palmar branch of the radial artery and innervated by the superficial branch of the radial nerve, was used in four patients for sensory reconstruction of the fingers. Two patients had degloving injuries of the hand and two had amputation injuries of the thumb. Three of the cases underwent free-flap transfers, and one case underwent a reverse-flow island flap. The size of these flaps was about 3 x 5 cm except in one case, where a 15 x 5 cm flap combined with a radial forearm flap was used. Sensory reinnervation was excellent and donor site morbidity was minimal in all four cases. An innervated radial thenar flap from the ipsilateral hand offers an alternative choice to reconstruct large palmar defects of the fingers. PMID:8724464

Omokawa, S; Mizumoto, S; Iwai, M; Tamai, S; Fukui, A

1996-05-01

300

Isotope-ratio-monitoring gas chromatography methods for high-precision isotopic analysis of nanomole  

E-print Network

Isotope-ratio-monitoring gas chromatography methods for high-precision isotopic analysis and a commercially available continuous-flow, gas chromatography interface (the Finnigan Gas Bench II). This work

Bebout, Gray E.

301

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

PubMed

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. PMID:9894321

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

1998-01-01

302

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...

303

Are RRab stars fully radial?  

NASA Astrophysics Data System (ADS)

Thanks to the space missions CoRoT and Kepler new oscillation frequencies have been discovered in the Fourier spectra of Blazhko RR Lyrae stars. The period doubling (PD) yields half-integer frequencies between the fundamental mode and its harmonics. In many cases the first and/or second radial overtone frequencies also appear temporally. Some stars show extra frequencies that were identified as potential non-radial modes. We show here that all these frequencies can be explained by pure radial pulsation as linear combinations of the frequencies of radial fundamental and overtone modes.

Benk?, József M.; Szabó, Róbert

2014-02-01

304

DESIGN ANALYSIS OF RADIAL INFLOW TURBINES  

NASA Technical Reports Server (NTRS)

This program performs a velocity-diagram analysis required for determining geometry and estimating performance for radial-inflow turbines. Input design requirements are power, mass flow rate, inlet temperature and pressure, and rotative rate. The design variables include stator-exit angle, rotor-exit-tip to rotor-inlet radius ratio, rotor-exit-hub to tip radius ratio, and the magnitude and radial distribution of rotor-exit tangential velocity. The program output includes diameters, total and static efficiences, all absolute and relative temperatures, pressures, and velocities, and flow angles at stator inlet, stator exit, rotor inlet, and rotor exit. Losses accounted for in this program by the internal loss model are three-dimensional (profile plus end wall) viscous losses in the stator and the rotor, the disk-friction loss on the back side of the rotor, the loss due to the clearance between the rotor tip and the outer casing, and the exit velocity loss. The flow analysis is one-dimensional at the stator inlet, stator exit, and rotor inlet, each of these calculation stations being at a constant radius. At the rotor exit where there is a variation in flow-field radius, an axisymmetric two-dimensional analysis is made using constant height sectors. Simple radial equilibrium is used to establish the static pressure gradient at the rotor exit. This program is written in FORTRAN V and has been implemented on a UNIVAC 1100 series computer with a memory requirement of approximately 22K of 36 bit words.

Glassman, A. J.

1994-01-01

305

Radialization as a new treatment for radial club hand.  

PubMed

"Radialization," a new technique for operative treatment of the radial club hand, is presented. It has been successfully used in 30 hands (23 patients) since 1979. It is named "radialization" because after all fibrotic tissues are excised, the hand and radial carpal bones are placed over the distal end of the ulna; the hand is fixed with a Kirschner wire in a position of moderate ulnar deviation. Usually, no carpal bones need to be removed. The improved mechanical forces are further stabilized by transposition of the radial wrist extensor and flexor to the ulnar side; this favors a better muscle balance. The optimal age for surgery is between 6 and 12 months. PMID:4078287

Buck-Gramcko, D

1985-11-01

306

Radially composite piezoelectric ceramic tubular transducer in radial vibration.  

PubMed

The radially composite piezoelectric tubular transducer is studied. It is composed of radially poled piezoelectric and a long metal tube. The electro-mechanical equivalent circuit of the radially poled piezoelectric and metal tube in radial vibration is obtained. Based on the force and velocity boundary conditions, the six-port electro-mechanical equivalent circuit for the composite tubular transducer is given and the resonance/anti-resonance frequency equations are obtained. The relationship between the resonance frequency and the dimensions is analyzed. Numerically simulated results obtained by the finite element method are compared with those from the analytical method. Composite piezoelectric tubular transducers are designed and manufactured. The resonance/anti-resonance frequencies are measured, and it is shown that the theoretical results are in good agreement with the simulated and experimental results. It is expected that radially composite piezoelectric tubular transducers can be used as high-power ultrasonic radiators in ultrasonic applications, such as ultrasonic liquid processing. PMID:22083782

Shuyu, Lin; Shuaijun, Wang

2011-11-01

307

Singular spectrum for radial trees  

E-print Network

We prove several results showing that absolutely continuous spectrum for the Laplacian on radial trees is a rare event. In particular, we show that metric trees with unbounded edges have purely singular spectrum and that generically (in the sense of Baire) radial trees have purely singular continuous spectrum.

Jonathan Breuer; Rupert L. Frank

2008-06-03

308

Chromatography resin support  

DOEpatents

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.

Dobos, James G. (North Augusta, SC)

2002-01-01

309

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

PubMed

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

Lindegren, S; Jensen, H; Jacobsson, L

2014-04-11

310

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

NASA Technical Reports Server (NTRS)

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

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

1974-01-01

311

Fun with Paper Chromatography.  

ERIC Educational Resources Information Center

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)

Coleman, Dava; Hounshell, Paul B.

1982-01-01

312

Radially sandwiched cylindrical piezoelectric transducer  

NASA Astrophysics Data System (ADS)

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.

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

2013-01-01

313

Radial distribution of thujaplicins in old growth and second growth western red cedar ( Thuja plicata Donn)  

Microsoft Academic Search

Radial distribution of thujaplicins in western red cedar (Thuja plicata Donn) trees of varying ages was studied in order to assess relative decay resistance of their wood. Samples were extracted with ethanol: benzene (1: 2), and the extractives were analyzed for thujaplicin codtent by a new method utilizing capillary gas chromatography of their methylated derivatives. The combined concentration of thujic

J. Nault

1988-01-01

314

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

PubMed

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

Gomaa, Ahmed; Boye, Joyce

2015-05-15

315

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

PubMed Central

?9-tetrahydrocannabinol (THC) is the primary target in oral fluid (OF) for detecting cannabis intake. However, additional biomarkers are needed to solve interpretation issues, such as the possibility of passive inhalation by identifying 11-nor-9-carboxy-THC (THCCOOH), and determining recent cannabis smoking by identifying cannabidiol (CBD) and/or cannabinol (CBN). We developed and comprehensively validated a microflow liquid chromatography (LC)–high resolution mass spectrometry method for simultaneous quantification of THC, THCCOOH, CBD and CBN in OF collected with the Oral-Eze® and Quantisal™ devices. One mL OF-buffer solution (0.25mL OF and 0.5mL of Oral-Eze buffer,1:3 dilution, or 0.75mL Quantisal buffer, 1:4 dilution) had proteins precipitated, and the supernatant subjected to CEREX™ Polycrom™ THC solid-phase extraction (SPE). Microflow LC reverse-phase separation was achieved with a gradient mobile phase of 10mM ammonium acetate pH 6 and acetonitrile over 10 min. We employed a Q Exactive high resolution mass spectrometer, with compounds identified and quantified by targeted-MSMS experiments. The assay was linear 0.5–50 ng/mL for THC, CBD and CBN, and 15–500 pg/mL for THCCOOH. Intra- and inter-day and total imprecision were <10.8%CV and bias 86.5–104.9%. Extraction efficiency was 52.4–109.2%, process efficiency 12.2– 88.9% and matrix effect ranged from ?86 to ?6.9%. All analytes were stable for 24h at 5°C on the autosampler. The method was applied to authentic OF specimens collected with Quantisal and Oral-Eze devices. This method provides a rapid simultaneous quantification of THCCOOH and THC, CBD, CBN, with good selectivity and sensitivity, providing the opportunity to improve interpretation of cannabinoid OF results by eliminating the possibility of passive inhalation and providing markers of recent cannabis smoking. PMID:23726246

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

2014-01-01

316

Cavity Ring-Down Spectroscopy as a Detector for Liquid Chromatography  

E-print Network

Cavity Ring-Down Spectroscopy as a Detector for Liquid Chromatography Kate L. Snyder and Richard N chromatography (HPLC). For this use, we have designed and implemented a Brewster's angle flow cell UV-vis absorption detector for the same path length. High performance liquid chromatography (HPLC

Zare, Richard N.

317

Ion Exchange Chromatography  

NSDL National Science Digital Library

This website contains an ion chromatography simulator that can be run online or can be downloaded. The simulator focuses on separations of proteins using Ion Chromatography. Also included is linked reference information, an example of a homework assignment using the simulator, and some information on protein structures.

318

Advanced proteomic liquid chromatography  

SciTech Connect

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.

Xie, Fang; Smith, Richard D.; Shen, Yufeng

2012-10-26

319

Chromatography Theory and Modes  

NSDL National Science Digital Library

This site is an introductory lecture in outline form about chromatography. It appears directed toward biochemical separations. The coverage is broad but not deep. Discussions of counter-current separations, gel permeation, and ion exchange are accompanied by some mention of partition, paper, and gas chromatography. Useful illustrations are also included.

320

Kool-Aid Chromatography  

ERIC Educational Resources Information Center

Offers guidelines and suggests activities that can introduce middle school students to the process and principles of chromatography in an inexpensive and safe manner. Proposes that experiences with Kool-aid and food coloring chromatography can provide insights into how scientists think, work, and communicate. (ML)

Jenkins, Christie L.

1986-01-01

321

Complications of radial head prostheses.  

PubMed

Radial head prostheses are indicated for treatment of complex radial head fractures not amenable for fixation. After the initial experience with silastic implants, metallic or pyrocarbon arthroplasty have been used for 20 years. Little is known about complications related to these implants. Main complications are related to loosening whether they are cemented or not cemented. Hypotheses have been proposed like inadequate stem design, insufficient cement technique, stress shielding, and foreign body reactions secondary to polyethylene wear. Pain and stiffness are other common complications often related to oversized radial head component or overstuffing of the joint with excessive lengthening of the radius. Instability can be another complication in the context of more complex trauma with lateral collateral ligament complex lesion and coronoid fracture. Fixation of the coronoid fracture, reinsertion of the lateral collateral ligament complex, and the use of monobloc radial head prosthesis are recommended to stabilize the joint. Finally, osteoarthritis is common with follow-up. PMID:25655903

Delclaux, Stéphanie; Lebon, Julie; Faraud, Amélie; Toulemonde, Julien; Bonnevialle, Nicolas; Coulet, Bertrand; Mansat, Pierre

2015-05-01

322

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

PubMed

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

Borai, E H; Mady, A S

2002-10-01

323

Sample concentration using optical chromatography  

NASA Astrophysics Data System (ADS)

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.

Hart, Sean J.; Terray, Alex; Arnold, Jonathan; Leski, Tomasz A.

2007-03-01

324

Gas turbine annular combustor with radial dilution air injection  

Microsoft Academic Search

This patent describes a radial flow gas turbine. It comprises: a rotor including turbine blades and a nozzle adjacent the turbine blades, the nozzle being adapted to direct hot gases at the turbine blades to cause rotation of the rotor; an annular combustor about the rotor and having a combustor outlet leading to the nozzle, the annular combustor having spaced

J. R. Shekelton; D. C. Johnson

1991-01-01

325

Liquid-phase chromatography detector  

DOEpatents

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.

Voigtman, E.G.; Winefordner, J.D.; Jurgensen, A.R.

1983-11-08

326

Liquid-phase chromatography detector  

DOEpatents

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.

Voigtman, Edward G. (Gainesville, FL); Winefordner, James D. (Gainesville, FL); Jurgensen, Arthur R. (Gainesville, FL)

1983-01-01

327

High power radial klystron oscillator  

SciTech Connect

The advantages of the radial klystron amplifier over the conventional klystron amplifier have been reported by Arman et al. Briefly, the radial structure of this design allows for much smaller impedances and thus higher power, the beam-cavity coupling is stronger because the beam travels inside the cavity, and the source is much more compact because there is no need for external magnetic fields. Here the author reports on possible advantages of the radial klystron oscillator over the radial klystron amplifier. The amplifying nature of certain HPM sources is often mandated by the requirement for synchronization and phase-locking of a number of sources in specific applications. In situations where amplification is solely adhered to for the purpose of achieving higher powers, the oscillator will be a better choice if a mechanism can be found to grow the desired mode at the required frequency. By switching to the oscillator mode there will be no need for priming the cavity or maintaining the phase. This simplifies the design and reduces the operational and maintenance cost of the source. Here he reports that an oscillator version of the radial klystron is possible and in fact more suitable for many applications. The mechanism for exciting and growing the mode will be transit-time effects thus providing all the beneficial features of the transit-time oscillators. The complications due to the presence of thin foils in the radial design still persist and will be dealt with in subsequent works. Numerical simulations using the PIC codes MAGIC and SOS indicate the radial klystron oscillator is a viable and efficient means of rf generation.

Arman, M.J. [Phillips Lab., Kirtland AFB, NM (United States)

1995-11-01

328

Heat transfer in a radially rotating square duct fitted with in-line transverse ribs  

Microsoft Academic Search

This paper describes an experimental study of heat transfer in a radially rotating square duct with two opposite walls fitted by transverse ribs. The manner in which rotation modifies the forced heat convection is considered for the case where the duct rotates about an axis perpendicular to the duct's axis of symmetry and the flow within is radially outward with

S. W. Chang; W. D. Morris

2003-01-01

329

Basic Liquid Chromatography  

NSDL National Science Digital Library

This online textbook offers a variety of information on high performance liquid chromatography (HPLC). Topics covered include instruments, detectors, theory, column selection, and pH effect. This website also contains links to a glossary, useful links, and manufacturer websites.

Dr. Yuri Kazakevich

330

Gas chromatography in space  

NASA Technical Reports Server (NTRS)

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.

Akapo, S. O.; Dimandja, J. M.; Kojiro, D. R.; Valentin, J. R.; Carle, G. C.

1999-01-01

331

Basic Liquid Chromatography  

NSDL National Science Digital Library

The online textbook, Basic Liquid Chromatography, is provided by Dr. Yuri Kazakevich and Dr. Harold McNair of Seton Hall University. For those needing review or an introduction to the subject, the well designed and easily read document contains a wealth of information. Sections include an introduction, instrumentation, detectors, theory, adsorbents, reversed phase, gel permeation chromatography, column selection, pH effect, and even an online short course.

Kazakevich, Yuri.

1996-01-01

332

Chromatography Nomenclature and Definitions  

NSDL National Science Digital Library

This website gives the International Union of Pure and Applied Chemistry approved definitions in the field of chromatography. It is critical for students to appreciate the importance of using standardized nomenclature and definitions. Sections of the site include general terminology, terms related to the chromatographic system, terms related to the chromatographic process and the theory of chromatography, terms related to detection, ion exchange, liquid-liquid distribution (solvent extraction) and other related subjects.

333

Precision radial velocities with CSHELL  

E-print Network

Radial velocity 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 radial velocity techniques. We present our methodology for achieving 58 m/s precision in the K band on the M0 dwarf GJ 281 using the CSHELL spectrograph at the 3-meter NASA IRTF. We also demonstrate our ability to recover the known 4 Mjup exoplanet Gl 86 b and discuss the implications for success in detecting planets around 1-3 Myr old T Tauri stars.

Crockett, Christopher J; Prato, Lisa; Johns-Krull, Christopher M; Jaffe, Daniel T; Beichman, Charles A

2011-01-01

334

Radial textured carbon nanoflake spherules  

NASA Astrophysics Data System (ADS)

A unique type of carbon structure, radial textured carbon nanoflake spherules, has been synthesized by a microwave plasma assisted chemical vapor deposition method. The spherules with a diameter of 1.2-35?m consist of a number of radially distributed carbon nanoflakes growing from a common core. The constituent nanoflakes are interlaced and perpendicular to the surface of spherules, forming a large amount of open edge planes. Thus, the carbon nanoflake spherules are isotropic graphite with a larger surface area and higher surface activity, which can be demonstrated by Raman scattering spectroscopy with two characteristic peaks of 860 and 1140cm-1.

Shang, N. G.; Staedler, T.; Jiang, X.

2006-09-01

335

"Impossible" reversed radial forearm free flap in microsurgical reconstruction.  

PubMed

The reversed radial forearm free flap is described and patient histories are presented to illustrate its unique reconstructive versatility. The valvular orientation of the deep and superficial forearm veins should theoretically oppose the reversed flow in this flap, but the venous flow is not compromised. In comparison to the anterograde forearm free flap the vascular pedicle is longer and the donor defect generates less functional and cosmetic complications because it is located on the proximal forearm. In a review of the literature anatomical details of the venous drainage are presented. Different opinions on reverse flow in forearm flaps are discussed and a new theory is proposed. PMID:8289645

Bauland, C G; van Twisk, R; Bos, M Y; Nicolai, J P

1993-01-01

336

Radial Velocity Techniques for Exoplanets  

NASA Astrophysics Data System (ADS)

The radial velocity technique was utilized to make the first exoplanet discoveries around Sun-like stars and continues to play a major role in the discovery and characterization of exoplanetary systems. In this chapter we describe how the technique works, and the current precision and limitations. We then review its major successes in the field of exoplanets. With more than 250 planet detections, it is the most prolific technique to date and has led to many milestone discoveries, such as hot Jupiters, multiplanet systems, transiting planets around bright stars, the planet-metallicity correlation, planets around M dwarfs and intermediate-mass stars, and recently, the emergence of a population of low-mass planets: Neptune-mass planets and super-Earths. In the near future radial velocities are expected to systematically explore the domain of rocky and icy planets down to a few Earth masses close to the habitable zone of their parent star. Radial velocity measurements will also be used to provide the necessary follow-up observations of transiting candidates detected by space missions. Finally, we also note alternative radial velocity techniques that may play an important role in the future.

Lovis, C.; Fischer, D.

2010-12-01

337

Design and experimental evaluation of compact radial-inflow turbines  

NASA Technical Reports Server (NTRS)

The application of a multistage 3D Euler solver to the aerodynamic design of two compact radial-inflow turbines is presented, along with experimental results evaluating and validating the designs. The objectives of the program were to design, fabricate, and rig test compact radial-inflow turbines with equal or better efficiency relative to conventional designs, while having 40 percent less rotor length than current traditionally-sized radial turbines. The approach to achieving these objectives was to apply a calibrated 3D multistage Euler code to accurately predict and control the high rotor flow passage velocities and high aerodynamic loadings resulting from the reduction in rotor length. A comparison of the advanced compact designs to current state-of-the-art configurations is presented.

Fredmonski, A. J.; Huber, F. W.; Roelke, R. J.; Simonyi, S.

1991-01-01

338

Freeze chromatography method and apparatus  

DOEpatents

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.

Scott, C.D.

1987-04-16

339

Performance of vaned radial diffusers  

E-print Network

. At the inlet station, the flow angles for the high flow rate case are about 10 percent larger than those for the low flow rate, especially near the shroud side. The effect of the flow rate level on the yaw angle distributions decreases as the flow proceeds... Piping system for mass flow measurement Photograph of pitot probe and yaw probe Photograph of probe setup for calibration Probe locations on shroud side 23 10 Detail of probe insertion Photograph of probe setup Vortex Test Vehicle 25 26 28 12...

Piemsomboon, Pornchai

1983-01-01

340

A model of a radially expanding and contracting lymphangion  

PubMed Central

The lymphatic system is an extensive vascular network featuring valves and contractile walls that pump interstitial fluid and plasma proteins back to the main circulation. Immune function also relies on the lymphatic system’s ability to transport white blood cells. Failure to drain and pump this excess fluid results in edema characterized by fluid retention and swelling of limbs. It is, therefore, important to understand the mechanisms of fluid transport and pumping of lymphatic vessels. Unfortunately, there are very few studies in this area, most of which assume Poiseuille flow conditions. In vivo observations reveal that these vessels contract strongly, with diameter changes of the order of magnitude of the diameter itself over a cycle that lasts typically 2–3 seconds. The radial velocity of the contracting vessel is on the order of the axial fluid velocity, suggesting that modeling flow in these vessels with a Poiseuille model is inappropriate. In this paper, we describe a model of a radially expanding and contracting lymphatic vessel and investigate the validity of assuming Poiseuille flow to estimate wall shear stress, which is presumably important for lymphatic endothelial cell mechanotransduction. Three different wall motions; periodic sinusoidal, skewed sinusoidal and physiologic wall motions, were investigated with steady and unsteady parabolic inlet velocities. Despite high radial velocities resulting from the wall motion, wall shear stress values were within 4% of quasi-static Poiseuille values. Therefore, Poiseuille flow is valid for the estimation of wall shear stress for the majority of the lymphangion contractile cycle. PMID:21377158

Rahbar, Elaheh

2011-01-01

341

RTOD- RADIAL TURBINE OFF-DESIGN PERFORMANCE ANALYSIS  

NASA Technical Reports Server (NTRS)

The RTOD program was developed to accurately predict radial turbine off-design performance. The radial turbine has been used extensively in automotive turbochargers and aircraft auxiliary power units. It is now being given serious consideration for primary powerplant applications. In applications where the turbine will operate over a wide range of power settings, accurate off-design performance prediction is essential for a successful design. RTOD predictions have already illustrated a potential improvement in off-design performance offered by rotor back-sweep for high-work-factor radial turbines. RTOD can be used to analyze other potential performance enhancing design features. RTOD predicts the performance of a radial turbine (with or without rotor blade sweep) as a function of pressure ratio, speed, and stator setting. The program models the flow with the following: 1) stator viscous and trailing edge losses; 2) a vaneless space loss between the stator and the rotor; and 3) rotor incidence, viscous, trailing-edge, clearance, and disk friction losses. The stator and rotor viscous losses each represent the combined effects of profile, endwall, and secondary flow losses. The stator inlet and exit and the rotor inlet flows are modeled by a mean-line analysis, but a sector analysis is used at the rotor exit. The leakage flow through the clearance gap in a pivoting stator is also considered. User input includes gas properties, turbine geometry, and the stator and rotor viscous losses at a reference performance point. RTOD output includes predicted turbine performance over a specified operating range and any user selected flow parameters. The RTOD program is written in FORTRAN IV for batch execution and has been implemented on an IBM 370 series computer with a central memory requirement of approximately 100K of 8 bit bytes. The RTOD program was developed in 1983.

Glassman, A. J.

1994-01-01

342

A study of the effects of converging and diverging flow on the instability of viscous fingers  

E-print Network

systems for a diverging flow geometry has been slightly modified so that the behavior of fingering for a converging flow geometry may be calculated, This modified theory predicts the correct functional relationship between pertinent variables... process Idealized fingering patterns for a radial system Theoretical dimensionless finger lengths for converging radial flow system . . . . . . . . . . . . . , . . . . , 23 Theoretical dimensionless finger lengths for diverging radial flow system 24...

Wylie, Joel Albert

1987-01-01

343

High Performance Liquid Chromatography  

NASA Astrophysics Data System (ADS)

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.

Talcott, Stephen

344

Micellar liquid chromatography  

NASA Astrophysics Data System (ADS)

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.

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

1999-12-01

345

Severity grading in radial dysplasia.  

PubMed

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

Vilkki, S K

2014-11-01

346

Radial Distribution Function (RDF) schematic  

NSDL National Science Digital Library

Schematic of the Radial Distribution Function (RDF). The radial distribution function, also known as RDF, g(r), or the pair correlation function, is a measure to determine the correlation between particles within a system. Specifically, it is a measure of, on average, the probability of finding a particle at a distance of r away from a given reference particle, relative to that for an ideal gas. The general algorithm involves determining how many particles are within a distance of r and r+dr away from a particle. This general theme is depicted in the schematic, where the red particle is our reference particle, and blue particles are those which are within the circular shell, dotted in red.

Iacovella, Christopher R.

2006-09-28

347

RADIAL STELLAR PULSATION AND THREE-DIMENSIONAL CONVECTION. II. TWO-DIMENSIONAL CONVECTION IN FULL AMPLITUDE RADIAL PULSATION  

SciTech Connect

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.

Geroux, Chris M.; Deupree, Robert G., E-mail: geroux@astro.ex.ac.uk [Institute for Computational Astrophysics and Department of Astronomy and Physics, Saint Mary's University, Halifax, NS B3H 3C3 (Canada)

2013-07-10

348

Radial Reflection Diffraction Tomography Notes  

SciTech Connect

We are developing the theory behind a new imaging modality which uses a single transducer rotating about its center to launch a field radially outward and collect the backscattered (reflected) field. We use diffraction tomography techniques, based upon a linearized version of the field scattering equation, to form images of the medium surrounding the transducer. As there is one transducer which both transmits the incident field and measures the backscattered field, the operation mode is multimonostatic.

Lehman, S K; Norton, S J

2002-06-27

349

Two different configurations of flow field-flow fractionation for size analysis of colloids  

SciTech Connect

Flow field-flow fractionation (F.FFF) is a technique for measuring the size of species in the colloidal range (1 nm to 1 [mu]m) which makes the use of the formation of a molecular or colloidal polarization layer at the surface of a filtering membrane. The species to be analyzed are introduced into a flow of liquid passing through a channel with porous walls (of pore size less than that of the colloids to be analyzed) which allow a certain controlled flow to pass through. The remaining fraction of the flow passes through the system, arraying the colloids to a nonspecific detector. The transit time of the colloids through the channel is found to be a function of their size and the permeation rate through the porous membrane. This chromatographic system can be calibrated by using known colloids, such as standard latex particles or fractionated polymer samples, and then used to determine the size of unknown colloids. Here the authors present results obtained in two different systems, an asymmetric module with a rectangular channel having a single flat membrane and a module based on a hollow ultrafiltration fiber with a radial symmetry. The common feature of the two systems is that there is only one fluid inlet. Measurements are reported for the mean size of various samples of real colloids, such as dextran macromolecules, emulsion paints, and milks, and a comparison is made with measurements using hydrodynamic chromatography (HDC), and photon correlation spectrometry. (PCS).

Granger, J.; Dodds, J. (CNRS-ENSIC, Nancy (France))

1992-10-01

350

Fluctuating Pressure Environments and Hydrodynamic Radial Force Mitigation for a Two Blade Unshrouded Inducer  

NASA Technical Reports Server (NTRS)

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.

Mulder, Andrew; Skelley, Stephen

2011-01-01

351

Velocidades radiales en Collinder 121  

NASA Astrophysics Data System (ADS)

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.

Arnal, M.; Morrell, N.

352

RAVE The RAdial Velocity Experiment  

E-print Network

RAVE (RAdial Velocity Experiment) is an ambitious program to conduct an all-sky survey (complete to V = 16) to measure the radial velocities, metallicities and abundance ratios of 50 million stars using the 1.2-m UK Schmidt Telescope of the Anglo-Australian Observatory (AAO), together with a northern counterpart, over the period 2006 - 2010. The survey will represent a giant leap forward in our understanding of our own Milky Way galaxy, providing a vast stellar kinematic database three orders of magnitude larger than any other survey proposed for this coming decade. RAVE will offer the first truly representative inventory of stellar radial velocities for all major components of the Galaxy. The survey is made possible by recent technical innovations in multi-fiber spectroscopy; specifically the development of the 'Echidna' concept at the AAO for positioning fibers using piezo-electric ball/spines. A 1m-class Schmidt telescope equipped with an Echidna fiber-optic positioner and suitable spectrograph would be ab...

Steinmetz, M

2002-01-01

353

RAVE: The RAdial Velocity Experiment  

E-print Network

RAVE (RAdial Velocity Experiment) is an ambitious program to conduct an all-sky survey (complete to V = 16) to measure the radial velocities, metallicities and abundance ratios of 50 million stars using the 1.2-m UK Schmidt Telescope of the Anglo-Australian Observatory (AAO), together with a northern counterpart, over the period 2006 - 2010. The survey will represent a giant leap forward in our understanding of our own Milky Way galaxy, providing a vast stellar kinematic database three orders of magnitude larger than any other survey proposed for this coming decade. RAVE will offer the first truly representative inventory of stellar radial velocities for all major components of the Galaxy. The survey is made possible by recent technical innovations in multi-fiber spectroscopy; specifically the development of the 'Echidna' concept at the AAO for positioning fibers using piezo-electric ball/spines. A 1m-class Schmidt telescope equipped with an Echidna fiber-optic positioner and suitable spectrograph would be able to obtain spectra for over 20 000 stars per clear night. Although the main survey cannot begin until 2006, a key component of the RAVE survey is a pilot program of 100 000 stars which may be carried out using the existing 6dF facility in unscheduled bright time over the period 2003--2005.

Matthias Steinmetz; for the RAVE science working group

2002-11-19

354

The Radial Velocity Experiment RAVE  

NASA Astrophysics Data System (ADS)

The Radial Velocity Experiment (RAVE) is an all-sky spectroscopic survey to measure radial velocities and stellar atmosphere parameters (temperature, surface gravity) and abundances of nearly half a million stars using the 6dF multi-object spectrograph on the 1.2-m UK Schmidt Telescope of the Anglo-Australian Observatory (AAO). RAVE is a multi-national endeavour involving scientists from 10 countries. RAVE started in April 2003 and has completed the data taking phase in April 2013. Almost 580 000 spectra have been taken in the Ca-triplet region (8410-8790 Å) for 480 000 southern hemisphere stars in the magnitude range 9 < I < 13 at a resolution of R=7500. The radial velocities measured in this survey are accurate to 2 kilometers per second. RAVE has meanwhile published three data releases, a fourth data release is scheduled for early 2014. Science applications of RAVE include the identification of substructure in the Milky Way and to derive constraints on the gravitational potential of our Galaxy.

Steinmetz, Matthias; RAVE Collaboration

2014-01-01

355

Nonstandard jump functions for radially symmetric shock waves  

SciTech Connect

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

Baty, Roy S.; Tucker, Don H.; Stanescu, Dan

2008-10-01

356

Tachoastrometry: astrometry with radial velocities  

NASA Astrophysics Data System (ADS)

Context. Spectra of composite systems (e.g., spectroscopic binaries) contain spatial information that can be retrieved by measuring the radial velocities (i.e., Doppler shifts) of the components in four observations with the slit rotated by 90 degrees in the sky. Aims: We aim at developing a framework to describe the method and to test its capabilities in a real case. Methods: By using basic concepts of slit spectroscopy we show that the geometry of composite systems can be reliably retrieved by measuring only radial velocity differences taken with different slit angles. The spatial resolution is determined by the precision with which differential radial velocities can be measured. Results: We use the UVES spectrograph at the VLT to observe the known spectroscopic binary star HD 188088 (HIP 97944), which has a maximum expected separation of 23 milli-arcseconds. We measure an astrometric signal in radial velocity of 276 m s-1 , which corresponds to a separation between the two components at the time of the observations of 18 ± 2 milli-arcseconds. The stars were aligned east-west. We describe a simple optical device to simultaneously record pairs of spectra rotated by 180 degrees, thus reducing systematic effects. We compute and provide the function expressing the shift of the centroid of a seeing-limited image in the presence of a narrow slit. Conclusions: The proposed technique is simple to use and our test shows that it is amenable for deriving astrometry with milli-arcsecond accuracy or better, beyond the diffraction limit of the telescope. The technique can be further improved by using simple devices to simultaneously record the spectra with 180 degrees angles. This device together with an optimized data analysis will further reduce the measurement errors. With tachoastrometry, radial velocities and astrometric positions can be measured simultaneously for many double line system binaries in an easy way. The method is not limited to binary stars, but can be applied to any astrophysical configuration in which spectral lines are generated by separate (non-rotational symmetric) regions.

Pasquini, L.; Cortés, C.; Lombardi, M.; Monaco, L.; Leão, I. C.; Delabre, B.

2015-02-01

357

Paper Chromatography with Leaves  

NSDL National Science Digital Library

In this activity on page 5 of the PDF, learners use chromatography to separate and identify pigments within various leaves. Learners soak leaf pieces in warmed rubbing alcohol and then dip coffee filter paper in the alcohol, lifting and separating the leaf pigments according to size.

American Chemical Society

2010-01-01

358

Analyze Candy Using Chromatography  

NSDL National Science Digital Library

Learners analyze candy-coated sweets using chromatography. Learners use this method to separate the various dyes used to make colored candy. Learners can try this activity with different types of candy or with candy of different colors and compare the results.

Museum of Science and Industry, Chicago

2012-01-01

359

Gas Chromatography Video  

NSDL National Science Digital Library

This is a high quality video module demonstrating the basics of gas chromatography. Highlights include different GC instruments and detectors as well as unique topics such as trouble shooting and interfacing the column that are not addressed in standard texts. This resource can be run (Shockwave Flash) from the home server or downloaded to your computer.

360

Gas Chromatography Application Notes  

NSDL National Science Digital Library

This site includes application notes on gas chromatography from 2000-2005 which have been presented at conferences. The applications could serve as a source of experiments for advanced teaching labs and may also assist those interested in solving analytical problems that involve separations.

361

Split Injection Gas Chromatography  

NSDL National Science Digital Library

This animation site deals specifically with split injection in gas chromatography. The animations are short (one to two minutes each) and can easily be shown in class as part of a lecture. They are extremely helpful in illustrating key components and concepts of chromatographic systems. Users are encouraged to explore the site and the other brief animations as well.

362

Paper Chromatography of Thioureas  

Microsoft Academic Search

IN the course of a current investigation, it became necessary to separate and identify minute amounts of N-substituted thioureas. Paper chromatography suggested itself as the method of choice for this purpose, and a technique has now been worked out which gives satisfactory and reproducible results on some thirty thioureas investigated, separately or in complex mixtures.

Anders Kjær; Kurt Rubinstein

1953-01-01

363

Extending Paper Chromatography Inquiry  

ERIC Educational Resources Information Center

One of the "good old" standard activities middle school students seem to enjoy is paper chromatography. The procedures and materials needed are relatively simple and the results can be colorful. All too often, the activity ends just after these colorful results are obtained, cutting short the potential it holds for some further inquiry. With some…

Finson, Kevin

2004-01-01

364

Dynamic programming using radial basis functions  

E-print Network

Dynamic programming using radial basis functions and Shepard approximations Oliver Junge, Alex, the target T is asymptotically stable. Oliver Junge, Alex Schreiber Dynamic programming using radial basis Dynamic programming using radial basis functions 3 #12;The Bellman equation V fulfills the Bellman

Hafstein, Sigurður Freyr

365

High Performance Thin Layer Chromatography.  

ERIC Educational Resources Information Center

Clarifies where in the scheme of modern chromatography high performance thin layer chromatography (TLC) fits and why in some situations it is a viable alternative to gas and high performance liquid chromatography. New TLC plates, sample applications, plate development, and instrumental techniques are considered. (JN)

Costanzo, Samuel J.

1984-01-01

366

Chromatography: Who Wrote the Note?  

NSDL National Science Digital Library

This lesson has students solving the mystery of a note by conducting chromatography. They will test different washable markers and see that different marker colors are made up of various pigments. They will compare and contrast the note chromatography with other chromatography results from a variety of markers.

Rebecca Hansing

367

Dual entry radial turbine gas generator  

SciTech Connect

This patent describes a high efficiency, single spool gas turbine gas generator comprising: (a) compressor means for providing an overall pressure ratio of greater than about 15:1, the compressor means including: (i) a first stage, double-entry centrifugal air compressor having a pair of entrances and a common exit, (ii) a second stage, centrifugal air compressor positioned adjacent to the first stage compressor, the second compressor stage having an entrance that is flow-connected to the first stage common exit and also having a second stage exit, and (iii) a shaft assembly for mechanically interconnecting the first and the second stage for rotation at the same angular speed; (b) combustor means operatively connected to the second stage exit for receiving the compressed air and combusting fuel using the compressed air to generate combustion gases; and (c) a single stage radial inflow turbine having an inlet and an outlet, the turbine being operatively connected directly to the shaft assembly drive and also being flow connected to the combustor means for receiving at the turbine inlet, and partially expanding, the combustion gases.

Mowill, R.J.

1987-02-10

368

Analyses of hydrodynamic radial forces on centrifugal pump impellers  

NASA Technical Reports Server (NTRS)

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.

Adkins, D. R.; Brennen, C. E.

1988-01-01

369

PRECISION RADIAL VELOCITIES WITH CSHELL  

SciTech Connect

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.

Crockett, Christopher J.; Prato, L. [Lowell Observatory, 1400 W Mars Hill Road, Flagstaff, AZ 86001 (United States); Mahmud, Naved I.; Johns-Krull, Christopher M. [Department of Physics and Astronomy, Rice University, MS-108, 6100 Main Street, Houston, TX 77005 (United States); Jaffe, Daniel T. [Department of Astronomy, University of Texas, R.L. Moore Hall, Austin, TX 78712 (United States); Beichman, Charles A., E-mail: crockett@lowell.edu, E-mail: lprato@lowell.edu, E-mail: naved@rice.edu, E-mail: cmj@rice.edu, E-mail: dtj@astro.as.utexas.edu [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

2011-07-10

370

Chromatography Can Separate!  

NSDL National Science Digital Library

In this chemistry activity, learners use thin layer chromatography to determine the molecular composition of different markers. First, they use pure rubbing alcohol as the liquid phase, then experiment with mixtures of alcohol and water to see which works best. Different black markers can be tried to see how their components compare. A quantitative measure of the "retention factor" is calculated to relate the distance traveled by the spot to the distance traveled by the mobile phase. A later experiment has learners try to identify an unknown ink sample by comparing it to known samples, and then opens it up to artistic pattern-making using chromatography and markers. The activity is written to be part of a kit, but the kit is not required.

Maisie Shaw

2010-01-01

371

Chromatography in Industry  

NASA Astrophysics Data System (ADS)

This review focuses on the chromatography research that has been carried out within industry or in close cooperation with industry and that has been reported in the scientific literature between 2006 and mid-2008. Companies in the health care sector, such as pharmaceutical and biotechnology companies, are the largest contributors. Industrial research seems to take place in an open environment in cooperation with academia, peer companies, and institutions. Industry appears ready to embrace new technologies as they emerge, but they focus strongly on making chromatography work robustly, reliably, rapidly, and automatically. “Hyphenated” systems that incorporate on-line sample-preparation techniques and mass-spectrometric detection are the rule rather than the exception. Various multidimensional separation methods are finding numerous applications. Strategies aimed at speeding up the development of new chromatographic methods remain the focus of attention. Also, there is a clear trend toward exploring chromatographic methods for parallel processing along with other strategies for high-throughput analysis.

Schoenmakers, Peter

2009-07-01

372

Paper chromatography of lipides  

Microsoft Academic Search

Summary  Procedures for qualitative and quantitative paper chromatography of lipides have been described in detail, together with some\\u000a practical applications.\\u000a \\u000a With the monochain lipides it was found that one developing system serves universally. The long aliphatic chains essentially\\u000a determine the chromatographic properties so that suitable conditions for chromatographing any lipide or lipide-like entity\\u000a are predictable. For the same reason total analysis

H. Schlenk; Joanne L. Gellerman; Jerry A. Tillotson; H. K. Mangold

1957-01-01

373

Ion Pairing Chromatography  

Microsoft Academic Search

The present state of ion-pair chromatography (IPC) is reviewed. Emphasis is placed on the theoretical modeling of the retention behavior of charged, zwitterionic, and neutral solutes, since the theory provides the generally good understanding of the factors affecting the separation. Although stoichiometric models were credited with the first easy-to-understand demonstration of the retention mechanism of IPC, they were thermodynamic models,

Teresa Cecchi

2008-01-01

374

Magnetically suspended centrifugal blood pump with a radial magnetic driver.  

PubMed

A new magnetic bearing has been designed to achieve a low electronic power requirement and high stiffness. The magnetic bearing consists of 1) radial passive forces between the permanent magnet ring mounted inside the impeller rotor and the electromagnet core materials in the pump casing and 2) radial active forces generated by the electromagnets using the two gap sensor signals. The magnetic bearing was assembled into a centrifugal rotary blood pump (CRBP) driven with a radial, magnetic coupled driver. The impeller vane shape was designed based upon the computational fluid dynamic simulation. The diameter and height of the CRBP were 75 mm and 50 mm, respectively. The magnetic bearing system required the power of 1.0-1.4 W. The radial impeller movement was controlled to within +/- 10 microm. High stiffness in the noncontrolled axes, Z, phi, and theta, was obtained by the passive magnetic forces. The pump flow of 5 L/min against 100 mm Hg head pressure was obtained at 1,800 rpm with the electrical to hydraulic efficiency being greater than 15%. The Normalized Index of Hemolysis (NIH) of the magnetic bearing CRBP was one fifth of the BioPump BP-80 and one half of the NIKKISO HPM-15 after 4 hours. The newly designed magnetic bearing with two degrees of freedom control in combination with optimized impeller vane was successful in achieving an excellent hemolytic performance in comparison with the clinical centrifugal blood pumps. PMID:15745136

Hoshi, Hideo; Katakoa, Kiroyuki; Ohuchi, Katsuhiro; Asama, Jun-ichi; Shinshi, Tadahiko; Shimokohbe, Akira; Takatani, Setsuo

2005-01-01

375

Coverage of a thumb wound and correction of a first web space contracture using a longitudinally split reverse radial forearm flap.  

PubMed

The authors describe a new design for a reverse-flow radial forearm flap. A total thumb amputation by severe avulsion was salvaged by microsurgical replantation and a reverse-flow radial forearm flap with a modified design to allow repair of two separate hand defects concomitantly. This newly described flap design for the reverse radial forearm flap offers a refined technique for simultaneous reconstruction of multiple defects in the hand. PMID:11601586

Akyürek, M; Safak, T; Keçik, A

2001-10-01

376

Aerodynamically induced radial forces in a centrifugal gas compressor: Part 2 -- Computational investigation  

Microsoft Academic Search

Radial loads and direction of a centrifugal gas compressor containing a high specific speed mixed flow impeller and a single tongue volute were determined both experimentally and computationally at both design and off-design conditions. The experimental methodology was developed in conjunction with a traditional ASME PTC-10 closed-loop test to determine radial load and direction. The experimental study is detailed in

M. B. Flathers; G. E. Bache?

1999-01-01

377

Effect of radial inflow on vortex intensification for a tornado-type wind turbine  

SciTech Connect

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.

Hsu, C.T.; Ide, H.

1982-09-01

378

A gas chromatography/combustion/isotope ratio mass spectrometry system for high-precision  

E-print Network

A gas chromatography/combustion/isotope ratio mass spectrometry system for high-precision d13 C methane cycle in the past. We developed a highly automated (continuous-flow) gas chromatography in the infrared spectrum. Today methane is recognised as an important greenhouse gas that affects the earth

Fischer, Hubertus

379

Quasi-linear gradients for capillary liquid chromatography with mass and tandem mass  

E-print Network

Quasi-linear gradients for capillary liquid chromatography with mass and tandem mass spectrometry Gradient elution, capillary liquid chromatography mass spectrometry was performed with linear, static capillary columns require flowrates in the nanoliter/min range, such low flow gradients are usually achieved

Dabiri, John O.

380

Radial migration in barred galaxies  

NASA Astrophysics Data System (ADS)

In this talk, I will present the result of high resolution numerical simulations of disk galaxies with various bulge/disk ratios evolving isolated, showing that: • Most of migration takes place when the bar strength is high and decreases in the phases of low activity (in agreement with the results by Brunetti et el. 2011, Minchev et al. 2011). • Most of the stars inside the corotation radius (CR) do not migrate in the outer regions, but stay confined in the inner disk, while stars outside CR can migrate either inwards or outwards, diffusing over the whole disk. • Migration is accompanied by significative azimuthal variations in the metallicity distribution, of the order of 0.1 dex for an initial gradient of ~-0.07 dex/kpc. • Boxy bulges are an example of stellar structures whose properties (stellar content, vertical metallicity, [?/Fe] and age gradients, ..) are affected by radial migration (see also Fig. 1).

Di Matteo, P.; Haywood, M.; Combes, F.; Semelin, B.; Babusiaux, C.; Gomez, A.

2015-03-01

381

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...

382

Hollow Cathode With Multiple Radial Orifices  

NASA Technical Reports Server (NTRS)

Improved hollow cathode serving as source of electrons has multiple radial orifices instead of single axial orifice. Distributes ion current more smoothly, over larger area. Prototype of high-current cathodes for ion engines in spacecraft. On Earth, cathodes used in large-diameter ion sources for industrial processing of materials. Radial orientation of orifices in new design causes current to be dispersed radially in vicinity of cathode. Advantageous where desireable to produce plasma more nearly uniform over wider region around cathode.

Brophy, John R.

1992-01-01

383

Flow measurements in a turbine scroll  

NASA Technical Reports Server (NTRS)

The paper presents a study conducted to determine experimentally the flow behavior in the combined scroll nozzle assembly of a radial inflow turbine. It is shown that hot film anemometry was used to measure the flow velocity in the scroll.

Tabakoff, W.; Sheoran, Y.; Kroll, K.

1979-01-01

384

Spectral line shapes in spherically symmetric radially moving clouds  

NASA Technical Reports Server (NTRS)

We present a method for the analysis of spectral line shapes arising in homogeneous, moving gas clouds in which velocity and molecular line excitation have power-law dependences on radial distance from the center. Analytical expressions are obtained for radial flows, for both optically thick and optically thin lines. The additional case of an optically thick line from a differentially rotating cloud is considered qualitatively. The method is applied to the interpretation of the C(12)O line observed in the direction of the Kleinmann-Low infrared nebula in Orion. While gravitational collapse and accelerated outflows would produce lines qualitatively similar to the observed profile, it does not appear to be possible to fit either model to the observations in detail.

Kuiper, T. B. H.; Rodriguez Kuiper, E. N.; Zuckerman, B.

1978-01-01

385

The vascular basis of the radial forearm flap.  

PubMed

The radial forearm flap is one of several valuable fasciocutaneous flaps. Therefore, its arterial and venous supply has been studied by dissection of 56 cadavers using various techniques, such as ink, latex, and barium sulfate injections. The relevant arterial branches tend to be in three groups with three associated and anastomosing perfusion zones. The blood supply of the distal radius is shown by latex injections. The vessels to tendons and nerves are briefly discussed. The flap is drained by superficial veins or radial artery venae comitantes or both. Each arterial perforator has one or two associated veins through which blood can pass into the venae comitantes. It is confirmed that the veins have valves, through which reverse flow has to occur in the pedicle of distally based island flaps. An explanation of how this is possible is given. The relevance of the findings to fasciocutaneous flaps in general is discussed. PMID:3941853

Timmons, M J

1986-01-01

386

Nonmicrosurgical use of the radial forearm flap for penile reconstruction.  

PubMed

Although the era of microsurgical techniques has greatly expanded the number of possible solutions for penile reconstruction, additional options are still needed for some unusual situations when microsurgery is not available or not desired. This article describes the first nonmicrosurgical use of the radial forearm flap for penile reconstruction. With this technique, an osteocutaneous radial forearm flap 15 x 20 cm in size is elevated as a reverse-flow island flap and used to create a neopenis in the classic "tube within a tube" fashion. The neopenis is then transferred to the recipient site as a distant flap, without dividing its vascular connection with the forearm. Once a complete healing is ensured after the following 2 to 3 weeks, the pedicle is cut and the penile reconstruction is completed. Since 1995, this technique was used for total penile reconstruction in four patients: two with congenital penile agenesis, one with penile amputation as a result of a high-voltage electrical injury, and one with total loss of the external genitalia as a result of a shotgun injury. The patients have been followed up for 1 to 4 years. Good results were achieved in all patients. In conclusion, non-microsurgical use of the radial forearm flap seems to be a useful alternative to create an innervated functionally and aesthetically acceptable neopenis when microsurgery is not available or not desired. Although it is a multistage procedure, it is easy to perform. Moreover, this technique provides all well-known advantages of the radial forearm flap in penile reconstruction but does not require the sophisticated equipment and expertise of microsurgery. This is a great advantage that enables surgeons without microsurgical skill to use the radial forearm flap for phallic reconstruction. The author believes that the described technique will be extremely useful in developing countries that have limited resources and where microsurgery is difficult to obtain. PMID:11176605

Mutaf, M

2001-01-01

387

Separating with Chromatography  

NSDL National Science Digital Library

In this experiment, learners separate different types of molecules in marker inks (using a technique called "thin layer chromatography"). Learners mark dots at the bottom of a strip of paper (stationary phase) and put the paper into a cup of water (liquid mobile phase) to see how the inks separate. The experiment is repeated with more colors, then mixtures of colors. The final investigation is to figure out who took a cookie, by analyzing the ink used to write a note left in the cookie jar, and comparing the ink to markers taken from two suspects. The activity is written as part of a kit, but can be done without the kit.

2012-06-26

388

Thin Layer Chromatography  

NSDL National Science Digital Library

Developed by the University of Southern Maine for college level chemistry students, this website offers instructive modules dealing with topics related to thin layer chromatography. Using Macromedia Shockwave, these interactive modules incorporate questions within the informative materials to advance users in their problem solving abilities. Topics covered at the website include RF Factor, hydrogen binding, visualization, and stationary phase. With the extensive use of diagrams and figures and the inclusion of a helpful glossary, students seeking assistance in chemistry can learn a great deal at this educational web site.

389

Gas Chromatography Experiment  

NSDL National Science Digital Library

This Microsoft Word document describes a Gas Chromatography experiment involving the separation and quantitation of four butyl alcohol isomers. It has a complete background about the components of a GC instrument (with labeled pictures) and their functions. The exercise includes a section devoted to the measurement of response factors of the detector in use (here an FID). This would be a good experiment for a new faculty member to use as is, with slight modification to make it relevant to the particular GC system to be used.

390

High Performance Liquid Chromatography  

NSDL National Science Digital Library

The North Carolina Community College System BioNetwork's interactive eLearning tools (IETs) are reusable chunks of training that can be deployed in a variety of courses or training programs. IETs are designed to enhance, not replace hands-on training. Learners are able to enter a hands-on lab experience better prepared and more confident. This particular IET delves into High Performance Liquid Chromatography (HPLC) and its application in discovering the amount of caffeine in two different drinks. Flash is required to participate in this learning module.

391

HPLC- High Performance Liquid Chromatography  

NSDL National Science Digital Library

This primer on High Performance Liquid Chromatography (HCLC) gives a brief history and definition of liquid chromatography (LC), LC techniques, and defines both HPLC and UltraPerformance Liquid Chromatography (UPLC Technology). The other chapters of the primer are available on the left side of the page: How Does High Performance Liquid Chromatography Work?, Identifying and Quantitating Compounds, HPLC Column Hardware, and HPLC Separation Modes. An appendix which defines HPLC nomenclature is also available. Each section is pepper with helpful and clear illustrations to help users visualize the processes and procedures presented.

392

Liquid chromatography of polymyxin B sulphate  

Microsoft Academic Search

A reversed-phase liquid chromatography method for analysis of polymyxin B sulphate is described. The method uses a YMC-Pack Pro, C18, 5 ?m, 250×4.6 mm I.D. column maintained at 30°C. The mobile phase comprises acetonitrile–sodium sulphate (0.7%, m\\/v)–phosphoric acid (6.8%, v\\/v dilution of 85%, m\\/m phosphoric acid)–water (22.25:50:5:22.75) at a flow-rate of 1.0 ml\\/min. Detection was by UV at 215 nm.

J. A. Orwa; A. Van Gerven; E. Roets; J. Hoogmartens

2000-01-01

393

Computer programs for axial flow compressor design  

NASA Technical Reports Server (NTRS)

Four computer programs examine effects of design parameters and indicate areas for research of multistage axial flow compressors. The programs provide information on velocity diagrams and stage-by-stage performance calculation, radial equilibrium of flow, radial distribution of total pressure, and off-design performance calculation.

Carmody, R. H.; Creveling, H. F.

1969-01-01

394

A Better Method for Filling Pasteur Pipet Chromatography Columns  

ERIC Educational Resources Information Center

An alternative method for the preparation of Pasteur pipet chromatography columns is presented that allows the column to be filled with solvent without bubbles and allows greater control of fluid flow while the materials to be separated are added. Students are required to wear gloves and goggles and caution should be used while handling glass…

Ruekberg, Ben

2006-01-01

395

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

NASA Technical Reports Server (NTRS)

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.

Snyder, Philip H.; Roelke, Richard J.

1988-01-01

396

Reestablished circulation after free radial forearm flap transfer.  

PubMed

New circulation in the free flap reestablished at the recipient site is the key to successful microvascular reconstructive surgery. This study is the first evaluation of long-term circulatory changes in nine free radial forearm flap transfers. Postoperatively, color Doppler studies revealed that the flow volume through the arterial pedicle increased rapidly during the first 3 days, gradually increased until day 14 (exceeding flow volume through the facial artery of the unoperated contralateral side), then decreased slightly until the sixth month. The pulsatility index, representing vascular resistance downstream, decreased successively. Ohm's law explains that this flow increase is caused by reduced vascular resistance downstream, attributed to changes in the vascularity of the transferred flap and in the recipient bed. The authors believe the circulatory changes are determinants of the clinical properties of the flap. This study addresses the importance of clarifying the events that transpire at the macroscopic circulatory level in the transferred free flap. PMID:15088205

Ichinose, Akihiro; Tahara, Shinya; Terashi, Hiroto; Yokoo, Satoshi

2004-04-01

397

Design and Numerical Simulation of Radial Inflow Turbine Volute  

NASA Astrophysics Data System (ADS)

The volute of a radial inflow turbine has to be designed to ensure that the desired rotor inlet conditions like absolute Mach number, flow angle etc. are attained. For the reasonable performance of vaneless volute turbine care has to be taken for reduction in losses at an appropriate flow angle at the rotor inlet, in the direction of volute, whose function is to convert gas energy into kinetic energy and direct the flow towards the rotor inlet at an appropriate flow angle with reduced losses. In literature it was found that the incompressible approaches failed to provide free vortex and uniform flow at rotor inlet for compressible flow regimes. So, this paper describes a non-dimensional design procedure for a vaneless turbine volute for compressible flow regime and investigates design parameters, such as the distribution of area ratio and radius ratio as a function of azimuth angle. The nondimensional design is converted in dimensional form for three different volute cross sections. A commercial computational fluid dynamics code is used to develop numerical models of three different volute cross sections. From the numerical models, losses generation in the different volutes are identified and compared. The maximum pressure loss coefficient for Trapezoidal cross section is 0.1075, for Bezier-trapezoidal cross section is 0.0677 and for circular cross section is 0.0438 near tongue region, which suggested that the circular cross section will give a better efficiency than other types of volute cross sections.

Shah, Samip P.; Channiwala, S. A.; Kulshreshtha, D. B.; Chaudhari, Gaurang

2014-12-01

398

Congenital isolated right radial club hand.  

PubMed

Congenital radial club hand (RCH) is an uncommon congenital anomaly characterized by various degrees of deficiency along the preaxial or radial side of the extremity. We present one such case of Type 4 congenital isolated RCH who presented to a tertiary care center in the Middle East. PMID:21483577

Salati, Sajad Ahmad; Rabah, Sari M

2010-01-01

399

Hydraulic radial piston pump intake porting arrangement  

Microsoft Academic Search

This patent describes a hydraulic radial piston pump having a slider block mounted on an eccentric of a rotary shaft in a hydraulic fluid supplied cavity. A piston is mounted in a cylinder disposed radially to the shaft. The piston has a flat working face at one end operating in the cylinder and a flat pad at an opposite end

1987-01-01

400

Modern Physics Problem: Radial Wave Functions  

NSDL National Science Digital Library

The two Physlets show a density plot of the Hydrogenic wavefunction and the solution to the radial equation. The word "density" refers to a method for plotting 3-D information on a two dimensional screen. Here it has nothing to do with the probability density in quantum mechanics. The radial solutions used here are the associated Laguerre polynomials scaled with a0 = 1.

Wolfgang Christian

401

Radial keratotomy associated endothelial degeneration  

PubMed Central

Purpose To describe the presentation and clinical course of eyes with a history of radial keratotomy (RK) and varying degrees of endothelial degeneration. Methods Retrospective case series were used. Results Thirteen eyes (seven patients) were identified with clinical findings of significant guttata and a prior history of RK. The mean age of presentation for cornea evaluation was 54.3 years (range: 38–72 years), averaging 18.7 years (range: 11–33 years) after RK. The presentation of guttata varied in degree from moderate to severe. Best corrected visual acuity (BCVA) ranged from 20/25 to 20/80. All patients had a history of bilateral RK, except one patient who did not develop any guttata in the eye without prior RK. No patients reported a family history of Fuch’s Dystrophy. One patient underwent a penetrating keratoplasty in one eye and a Descemet’s stripping automated endothelial keratoplasty (DSAEK) in the other eye. Conclusions RK may induce a spectrum of endothelial degeneration. In elderly patients, the findings of guttata may signify comorbid Fuch’s dystrophy in which RK incisions could potentially hasten endothelial decomposition. In these select patients with stable cornea topography and prior RK, DSAEK may successfully treat RK endothelial degeneration. PMID:22347792

Moshirfar, Majid; Ollerton, Andrew; Semnani, Rodmehr T; Hsu, Maylon

2012-01-01

402

Detection and recognition of radial frequency patterns.  

PubMed

Detection thresholds for radial deformations of circular contours were measured using a range of radii and contour peak spatial frequencies. For radial frequencies above two cycles, thresholds were found to be a constant fraction of the mean radius across a four-octave range of pattern radii and peak spatial frequencies (mean Weber fraction: 0.003-0.004). At low radial frequencies, thresholds were unaffected by contrast reduction. In 167 ms presentations, subjects were able to identify radial frequencies of six cycles and below with an accuracy of over 90% correct even when phase was randomized. The extreme sensitivity of subjects to these radial deformations (as low as 2-4 s of arc) cannot be explained by local orientation or curvature analysis, and points instead to the global pooling of contour information at intermediate levels of form vision. PMID:9893789

Wilkinson, F; Wilson, H R; Habak, C

1998-11-01

403

Reversed Phase Chromatography TOSOH BIOSCIENCE  

E-print Network

Columns IV. Ordering information TSK-GEL RPC Columns Reversed Phase Chromatography #12;Polar and non-polarReversed Phase Chromatography TOSOH BIOSCIENCE Separations Business Unit Reversed Phase is never-Octyl · TSK-GEL Super-Phenyl For polar compounds that will not be retarded on standard RP columns, the HILIC

Lebendiker, Mario

404

Multiplex gas chromatography  

NASA Technical Reports Server (NTRS)

The principles of the multiplex gas chromatography (GC) technique, which is a possible candidate for chemical analysis of planetary atmospheres, are discussed. Particular attention is given to the chemical modulators developed by present investigators for multiplex GC, namely, the thermal-desorption, thermal-decomposition, and catalytic modulators, as well as to mechanical modulators. The basic technique of multiplex GC using chemical modulators and a mechanical modulator is demonstrated. It is shown that, with the chemical modulators, only one gas stream consisting of the carrier in combination with the components is being analyzed, resulting in a simplified instrument that requires relatively few consumables. The mechanical modulator demonstrated a direct application of multiplex GC for the analysis of gases in atmosphere of Titan at very low pressures.

Valentin, Jose R.

1990-01-01

405

Hydrodynamic effects in a misaligned radial face seal  

NASA Technical Reports Server (NTRS)

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.

Etsion, I.

1977-01-01

406

Anderson Localization for radial tree-like random quantum graphs  

E-print Network

We prove that certain random models associated with radial, tree-like, rooted quantum graphs exhibit Anderson localization at all energies. The two main examples are the random length model (RLM) and the random Kirchhoff model (RKM). In the RLM, the lengths of each generation of edges form a family of independent, identically distributed random variables (iid). For the RKM, the iid random variables are associated with each generation of vertices and moderate the current flow through the vertex. We consider extensions to various families of decorated graphs and prove stability of localization with respect to decoration. In particular, we prove Anderson localization for the random necklace model.

Peter D. Hislop; Olaf Post

2008-06-16

407

Non-Radial Pulsations in Components of Symbiotic Stars  

NASA Astrophysics Data System (ADS)

Photometric observations of symbiotic stars in the blue and in the red spectral regions make it possible to reveal non-radial oscillations both of the cool and of the hot components. Light variations of red giants in the symbiotic systems CI Cyg and AG Peg show several periods in the 10 80d range, interpreted as p-mode pulsations. These modes are excited by a bright spot produced by radiation flux from the hot component. The spot moves on the red giant’s photosphere at a velocity close to the sound speed. During the active phase of the symbiotic star CH Cyg, at least 25 frequencies of oscillations in the 150 6000 s range of periods were found in the light of the white dwarf. Their features correspond to non-radial g-modes. In the frame of 2D gas dynamical non-adiabatic models, the interaction between gas flows and the accretion disk leads to formation of a system of shock waves propagating towards the compact object, which is one of possible mechanisms to excite non-radial pulsations of white dwarfs in symbiotic systems.

Bondar, N. I.; Prokoféva, V. V.

2005-04-01

408

Experimental Radial Density Profiles in Wire Array Z-Pinches  

NASA Astrophysics Data System (ADS)

The ablation processes occurring in wire arrays are fundamental to the evolution of the radial density profile, the development of precursor structures, and the trajectory of the final implosion of the main array mass. During the flow of plasma to the array axis, a quasi-periodic axial modulation in the density is observed experimentally for all array materials. The wavelength of this `flare' structure varies with material, but the mechanism which seeds the development of this axial modulation axis remains unresolved. This is often introduced into numerical simulations by artificially by use of either an initial axial mass or temperature variation at the appropriate periodicity in order to emulate the experiment. Experimental characterization of the evolution of the radial density profile will provide a constraint for the initial conditions of the simulation. This paper describes radiographic and interferometric data from wire array experiments on the MAGPIE generator at Imperial College London. In particular, two-frame radiography is applied to image a single wire core at multiple times to study the development of the radial flare structure, and these data are compared to results from the Gorgon 3D MHD code. This research was sponsored by the NNSA under DOE Cooperative Agreement DE-F03-02NA00057.

Bott, Simon; Lebedev, S.; Bland, S.; Chittenden, J.; Haines, M.; Hall, G.; Rapley, J.; Suzuki, F.; Marocchino, A.; Palmer, J.; Ampleford, D.; Jennings, C.

2006-10-01

409

Modeling the radial abundance distribution of the transition galaxy ngc 1313  

E-print Network

NGC 1313 is the most massive disk galaxy showing a flat radial abundance distribution in its interstellar gas, a behavior generally observed in magellanic and irregular galaxies. We have attempted to reproduce this flat abundance distribution using a multiphase chemical evolution model, which has been previously used sucessfully to depict other spiral galaxies along the Hubble morphological sequence. We found that it is not possible to reproduce the flat radial abundance distribution in NGC 1313, and at the same time, be consistent with observed radial distributions of other key parameters such the surface gas density and star formation profiles. We conclude that a more complicated galactic evolution model including radial flows, and possibly mass loss due to supernova explosions and winds, is necessary to explain the apparent chemical uniformity of the disk of NGC 1313

Mercedes Molla; Jean-Rene Roy

1999-03-09

410

Rotating stall control in a high-speed stage with inlet distortion. Part 1: Radial distortion  

SciTech Connect

This paper presents the first attempt to stabilize rotating stall in a single-stage transonic axial flow compressor with inlet distortion using active feedback control. The experiments were conducted at the NASA Lewis Research Center on a single-stage transonic core compressor inlet stage. An annular array of 12 jet-injectors located upstream of the rotor tip was used for forced response testing and to extend the compressor stable operating range. Results for radial distortion are reported in this paper. First, the effects of radial distortion on the compressor performance and the dynamic behavior were investigated. Control laws were designed using empirical transfer function estimates determined from forced response results. The transfer function indicated that the compressor dynamics are decoupled with radial inlet distortion, as they are for the case of undistorted inlet flow. Single-input-single-output (SISO) control strategies were therefore used for the radial distortion controller designs. Steady axisymmetric injection of 4 percent of the compressor mass flow resulted in a reduction in stalling mass flow of 9.7 percent relative to the case with inlet distortion and no injection. Use of a robust H{sub {infinity}} controller with unsteady nonaxisymmetric injection achieved a further reduction in stalling mass flow of 7.5 percent, resulting in a total reduction of 17.2 percent.

Spakovszky, Z.S.; Weigl, H.J.; Paduano, J.D. [Massachusetts Inst. of Technology, Cambridge, MA (United States). Gas Turbine Lab.; Schalkwyk, C.M. van [Scientific Systems Co., Woburn, MA (United States); Suder, K.L.; Bright, M.M. [NASA Lewis Research Center, Cleveland, OH (United States)

1999-07-01

411

A radial-flow batch drier for maize  

Microsoft Academic Search

Design and construction of a New Zealand-made batch maize drier are described. The dner has a capacity of 102 t (100 tons) per day at 10% moisture content extraction.Details of performance testing are given, together with approximate heat and moisture balances for each test.

G. H. Palmer; S. Harris

1973-01-01

412

Material flow determination for radial flexible profile ring rolling  

Microsoft Academic Search

Regarding the increasing demand on annular components with complex geometries, a flexible process has been developed at the\\u000a IBF to profile sleeve shaped rings. Unlike processes using grooved tools, here diverse contours can be realized on the inner\\u000a surface using one “universal” tool. By extending the tool kinematics and developing an adequate forming strategy the general\\u000a feasibility of the process

Ingo Tiedemann; Gerhard Hirt; Reiner Kopp; Dennis Michl; Nastaran Khanjari

2007-01-01

413

Automated gas chromatography  

DOEpatents

An apparatus and process for the continuous, near real-time monitoring of low-level concentrations of organic compounds in a liquid, and, more particularly, a water stream. A small liquid volume of flow from a liquid process stream containing organic compounds is diverted by an automated process to a heated vaporization capillary where the liquid volume is vaporized to a gas that flows to an automated gas chromatograph separation column to chromatographically separate the organic compounds. Organic compounds are detected and the information transmitted to a control system for use in process control. Concentrations of organic compounds less than one part per million are detected in less than one minute.

Mowry, Curtis D. (Albuquerque, NM); Blair, Dianna S. (Albuquerque, NM); Rodacy, Philip J. (Albuquerque, NM); Reber, Stephen D. (Corrales, NM)

1999-01-01

414

14 CFR 73.5 - Bearings; radials; miles.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 false Bearings; radials; miles. 73.5 Section 73.5 Aeronautics and Space ...AIRSPACE General § 73.5 Bearings; radials; miles. (a) All bearings and radials in this part are true from point...

2010-01-01

415

14 CFR 71.7 - Bearings, radials, and mileages.  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 2011-01-01 false Bearings, radials, and mileages. 71.7 Section...ROUTES; AND REPORTING POINTS § 71.7 Bearings, radials, and mileages. All bearings and radials in this part are true and are...

2011-01-01

416

14 CFR 71.7 - Bearings, radials, and mileages.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 2013-01-01 false Bearings, radials, and mileages. 71.7 Section...ROUTES; AND REPORTING POINTS § 71.7 Bearings, radials, and mileages. All bearings and radials in this part are true and are...

2013-01-01

417

14 CFR 71.7 - Bearings, radials, and mileages.  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 2012-01-01 false Bearings, radials, and mileages. 71.7 Section...ROUTES; AND REPORTING POINTS § 71.7 Bearings, radials, and mileages. All bearings and radials in this part are true and are...

2012-01-01

418

14 CFR 71.7 - Bearings, radials, and mileages.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 2010-01-01 false Bearings, radials, and mileages. 71.7 Section...ROUTES; AND REPORTING POINTS § 71.7 Bearings, radials, and mileages. All bearings and radials in this part are true and are...

2010-01-01

419

14 CFR 71.7 - Bearings, radials, and mileages.  

Code of Federal Regulations, 2014 CFR

... 2014-01-01 2014-01-01 false Bearings, radials, and mileages. 71.7 Section...ROUTES; AND REPORTING POINTS § 71.7 Bearings, radials, and mileages. All bearings and radials in this part are true and are...

2014-01-01

420

Micro-polarimeter for high performance liquid chromatography  

DOEpatents

A micro-polarimeter interfaced with a system for high performance liquid chromatography, for quantitatively analyzing micro and trace amounts of optically active organic molecules, particularly carbohydrates. A flow cell with a narrow bore is connected to a high performance liquid chromatography system. Thin, low birefringence cell windows cover opposite ends of the bore. A focused and polarized laser beam is directed along the longitudinal axis of the bore as an eluent containing the organic molecules is pumped through the cell. The beam is modulated by air gap Faraday rotators for phase sensitive detection to enhance the signal to noise ratio. An analyzer records the beams's direction of polarization after it passes through the cell. Calibration of the liquid chromatography system allows determination of the quantity of organic molecules present from a determination of the degree to which the polarized beam is rotated when it passes through the eluent.

Yeung, Edward E. (Ames, IA); Steenhoek, Larry E. (Wilmington, DE); Woodruff, Steven D. (Morgantown, WV); Kuo, Jeng-Chung (Skokie, IL)

1985-01-01

421

Acquired radial club hand. A case report.  

PubMed

An unusual case of acquired radial club hand is presented. It was almost indistinguishable from the congenital variety, but arose from a mismanaged cutaneous infection of the wrist. Surgical treatment resulted in a functionally and cosmetically acceptable hand. PMID:7152889

Iregbulem, L M

1982-06-01

422

Meshless Galerkin methods using radial basis functions  

Microsoft Academic Search

We combine the theory of radial basis functions with the field of Galerkin methods to solve partial differential equations. After a general description of the method we show convergence and derive error estimates for smooth problems in arbitrary dimensions.

Holger Wendland

1999-01-01

423

Radial keratotomy for myopia - series (image)  

MedlinePLUS

... keratotomy is used to correct nearsightedness, also called myopia. Myopia occurs when the cornea and lens focus light ... of, rather than on, the retina. Correction of myopia with radial keratotomy eliminates the need for corrective ...

424

Radial pattern of nuclear decay processes  

SciTech Connect

At high level density of nuclear states, a separation of diffferent time scales is observed (trapping effect). We calculate the radial profile of partial widths in the framework of the continuum shell model for some 1[sup [minus

Iskra, W.; Mueller, M.; Rotter, I. (Forschungszentrum Rossendorf, Institut fuer Kern- und Hadronenphysik, D-01314 Dresden (Germany) Soltan Institute for Nuclear Studies, PL-00-681 Warszawa (Poland) Technische Universitaet Dresden, Institut fuer Theoretische Physik, D-01062 Dresden (Germany))

1995-04-01

425

Radial coolant channels fabricated by simplified method  

NASA Technical Reports Server (NTRS)

Radial coolant channels for distributing a coolant over the inner wall of a circular section are fabricated by cold-rolling indentations on the inside circumference of the base section and covering the indentations with a rolled flange.

Freeman, A.

1966-01-01

426

Radial construction of an arterial wall.  

PubMed

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. PMID:22975322

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

427

Fluctuating Pressure Environments and Hydrodynamic Radial Force Mitigation for a Two Blade Unshrouded Inducer  

NASA Technical Reports Server (NTRS)

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.

Mulder, Andrew; Skelley, Stephen

2011-01-01

428

Laser Doppler perfusion imaging of the radial forearm flap: a clinical study.  

PubMed

Laser Doppler perfusion imaging (LDPI) allows non-invasive assessment of blood flow in a predefined area of skin rather than at one single point. We have used LDPI to study the pattern of skin blood flow in the radial forearm flap before and after the flap has been raised. The data were collected from a consecutive series of 11 patients with cancer of the oral cavity or oropharynx in whom the radial forearm flap had been used during the reconstructive procedure. Reperfusion leads to an immediate hyperaemic response both in the flap and the surrounding skin. This hyperaemia remains for at least the first 30 minutes after reperfusion. The perfusion of the radial side of the forearm skin distal to the flap is significantly lower than that on the ulnar side after the skin island has been raised and the distal artery divided. We suggest that LDPI is useful for monitoring the perfusion of free skin flaps. PMID:16537257

Zdolsek, Johann M; Droog, Eric J; Thorfinn, Johan; Lidman, Disa

2006-01-01

429

Cooled High-temperature Radial Turbine Program 2  

NASA Technical Reports Server (NTRS)

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.

Snyder, Philip H.

1991-01-01

430

Variable area radial turbine fabrication and test program  

NASA Technical Reports Server (NTRS)

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.

Rogo, C.

1986-01-01

431

Experimental evaluation of a translating nozzle sidewall radial turbine  

NASA Technical Reports Server (NTRS)

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.

Roelke, Richard J.; Rogo, Casimir

1987-01-01

432

Computer program for design analysis of radial-inflow turbines  

NASA Technical Reports Server (NTRS)

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.

Glassman, A. J.

1976-01-01

433

Chromatography (LC/GC) Online  

NSDL National Science Digital Library

Chromatography (LC/GC) Online magazine is a very good source for relatively short articles about fundamental chromatographic issues as well as applications. The content is appropriate for introductory analytical courses (e.g. quant) and for instrumental analysis courses.

434

A Mini Axial and a Permanent Maglev Radial Heart Pump§  

PubMed Central

The implantability and durability have been for decades the focus of artificial heart R&D. A mini axial and a maglev radial pump have been developed to meet with such requirements. The mini axial pump weighing 27g (incl.5g rotor) has an outer diameter of 21mm and a length of 10mm in its largest point, but can produce a maximal blood flow of 6l/min with 50mmHg pressure increase. Therefore, it is suitable for the patients of 40-60kg body weight. For other patients of 60-80kg or 80-100kg body weight, the mini axial pumps of 23mm and 25mm outer diameter had been developed before, these devices were acknowledged to be the world smallest LVADs by Guinness World Record Center in 2004. The permanent maglev radial pump weighing 150g is a shaft-less centrifugal pump with permanent magnetic bearings developed by the author. It needs no second coil for suspension of the rotor except the motor coil, different from all other maglev pumps developed in USA, Japan, European, etc. Thus no detecting and controlling systems as well as no additional power supply for maglev are necessary. The pump can produce a blood flow up to as large as 10l/min against 100mmHg pressure. An implantable and durable blood pump will be a viable alternative to natural donor heart for transplantation. PMID:19662120

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

2007-01-01

435

Waves in Radial Gravity Using Magnetic Fluid  

NASA Technical Reports Server (NTRS)

Terrestrial laboratory experiments studying various fluid dynamical processes are constrained, by being in an Earth laboratory, to have a gravitational body force which is uniform and unidirectional. Therefore fluid free-surfaces are horizontal and flat. Such free surfaces must have a vertical solid boundary to keep the fluid from spreading horizontally along a gravitational potential surface. In atmospheric, oceanic, or stellar fluid flows that have a horizontal scale of about one-tenth the body radius or larger, sphericity is important in the dynamics. Further, fluids in spherical geometry can cover an entire domain without any sidewall effects, i.e. have truly periodic boundary conditions. We describe spherical body-force laboratory experiments using ferrofluid. Ferrofluids are dilute suspensions of magnetic dipoles, for example magnetite particles of order 10 nm diameter, suspended in a carrier fluid. Ferrofluids are subject to an additional body force in the presence of an applied magnetic field gradient. We use this body force to conduct laboratory experiments in spherical geometry. The present study is a laboratory technique improvement. The apparatus is cylindrically axisymmetric. A cylindrical ceramic magnet is embedded in a smooth, solid, spherical PVC ball. The geopotential field and its gradient, the body force, were made nearly spherical by careful choice of magnet height-to-diameter ratio and magnet size relative to the PVC ball size. Terrestrial gravity is eliminated from the dynamics by immersing the "planet" and its ferrofluid "ocean" in an immiscible silicone oil/freon mixture of the same density. Thus the earth gravity is removed from the dynamics of the ferrofluid/oil interface and the only dynamically active force there is the radial magnetic gravity. The entire apparatus can rotate, and waves are forced on the ferrofluid surface by exterior magnets. The biggest improvement in technique is in the wave visualization. Fluorescing dye is added to the oil/freon mixture and an argon ion laser generates a horizontal light that can be scanned vertically. Viewed from above, the experiment is a black circle with wave deformations surrounded by a light background. A contour of the image intensity at any light sheet position gives the surface of the ferrofluid "ocean" at that "latitude". Radial displacements of the waves as a function of longitude are obtained by subtracting the contour line positions from a no-motion contour at that laser sheet latitude. The experiments are run by traversing the forcing magnet with the laser sheet height fixed and images are frame grabbed to obtain a time-series at one latitude. The experiment is then re-run with another laser-sheet height to generate a full picture of the three-dimensional wave structure in the upper hemisphere of the ball as a function of time. We concentrate here on results of laboratory studies of waves that are important in Earth's atmosphere and especially the ocean. To get oceanic scaling in the laboratory, the experiment must rotate rapidly (4-second rotation period) so that the wave speed is slow compared to the planetary rotation speed as in the ocean. In the Pacific Ocean, eastward propagating Kelvin waves eventually run into the South American coast. Theory predicts that some of the wave energy should scatter into coastal-trapped Kelvin waves that propagate north and south along the coast. Some of this coastal wave energy might then scatter into mid-latitude Rossby waves that propagate back westward. Satellite observations of the Pacific Ocean sea-surface temperature and height seem to show signatures of westward propagating mid-latitude Rossby waves, 5 to 10 years after the 1982-83 El Nino. The observational data is difficult to interpret unambiguously owing to the large range of motions that fill the ocean at shorter timescales. This series of reflections giving eastward, north- ward, and then westward traveling waves is observed cleanly in the laboratory experiments, confirming the theoretical expectations

Ohlsen, D. R.; Hart, J. E.; Weidman, P. D.

1999-01-01

436

Effect of radial inflow on vortex intensification for a tornado-type wind turbine  

Microsoft Academic Search

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

C. T. Hsu; H. Ide

1982-01-01

437

Large resistivity in numerical simulations of radially self-similar outflows  

NASA Astrophysics Data System (ADS)

We investigate conditions in a radially self-similar outflow in the regime of large resistivity. Using the PLUTO code, we performed simulations with proper choice of boundary conditions, relaxed at the footpoints of critical surfaces in the flow. We investigate outflow propagation in a high-resistive disk corona, and compare it to the results with small or vanishing resistivity.

?emelji?, Miljenko; Vlahakis, Nektarios; Tsinganos, Kanaris

2011-08-01

438

Digital artery pseudoaneurysm in a patient with previous radial artery harvest  

PubMed Central

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

Plant, Mathew A; Panchapakesan, Vivek

2011-01-01

439

Formation and evolution of radial fracture systems on Venus  

NASA Technical Reports Server (NTRS)

A survey of approximately 90 percent of the surface of Venus using Magellan data has been carried out to locate all radial fracture systems and to assess their association with other features such as volcanic edifices and coronae. Squyres et al. and Stofan et al. have discussed the association of radial fracture features in relation to coronae features, our approach was to assess the associations of all of the fracture systems. These fracture systems have two broad types of form - some fracture systems are associated with updomed topography, radiate from a point and have relatively uniform fracture lengths while others have a wider range of fracture lengths and radiate from the outer edge of a central caldera. Squyres et al. and Stofan et al. have interpreted both types of feature as reflecting tectonic fracturing resulting from uplift of the surface as a mantle plume impinges upon the crust. While it is true that a number of features are related to uplift and that such uplift will induce stresses consistent with radial fracturing, we explore the possibility that these fractures are not exclusively of tectonic origin. Purely tectonic fracturing will tend to generate a few main fractures/faults along which most of the stresses due to uplift will be accommodated leading to the triple-junction form common for terrestrial updoming. Though this type of feature is observed on Venus (e.g., feature located at 34S86), the majority of radial fracture systems display much more intensive fracturing than this through a full 360 degrees; this is difficult to explain by purely tectonic processes. The association of many of the fractures with radial lava flows leads us to interpret these fractures as reflecting dike emplacement: the form of the fractures being consistent with primarily vertical propagation from the head of a mantle plume. In the case of the second type of fracture system (those radiating from a central caldera), an even stronger case can be made that the fractures are not of tectonic origin. These features are not as commonly associated with updoming of the surface and where they are, the fractures extend out well beyond the edge of the topographic rise - an observation which is not consistent with the fractures being of tectonic uplift origin. Furthermore the fractures have a distribution of lengths (many short, fewer long) which is characteristic of dike swarms, and show direct associations with calderas and lava flows consistent with a volcanic origin. In addition, the longest fractures have a radial pattern only close to the center of the system but bend with distance to align themselves with the regional stress field - this behavior is very difficult to explain on purely tectonic grounds but is a pattern commonly seen for terrestrial dikes. For these reasons, we argue that many, if not the majority, of radial fracture systems found on Venus are the surface reflection of dike swarms, those associated with positive topography reflecting vertical emplacement and those radiating from calderas reflecting lateral propagation.

Parfitt, E. A.; Head, James W.

1993-01-01

440

Application of radial-splitters for improved wide-angle diffuser performance in a blowdown tunnel  

NASA Technical Reports Server (NTRS)

Severe flow separation in the 15:1 area-ratio, 38 deg total angle conical diffuser preceding the settling-chamber of an intermittent blowdown wind tunnel was eliminated by the use of a novel radial-splitter arrangement. As a consequence, the operating life of settling-chamber screens was greatly extended and test-section flow steadiness improved, with no penalty in the tunnel running time.

Rao, D. M.; Seshadri, S. N.

1976-01-01

441

Behavior of three-dimensional boundary layers in a radial inflow turbine scroll  

SciTech Connect

A detailed experimental investigation was carried out to examine the three-dimensional boundary layer characteristics in a radial inflow turbine scroll. Some basic flow phenomena and growth of secondary flow were also investigated. In the inlet region of the scroll, the incoming boundary layer begins to have a skewed nature, namely the radially inward secondary flow caused by the radial pressure gradient. From the inlet region to one third of the scroll circumference, the secondary flow grows so strongly that most of the low-momentum fluid in the incoming boundary layer is transported to the nozzle region. The succeeding elimination of the low-momentum fluid in the boundary layer suppresses growth of the boundary layer farther downstream, where the boundary layer shows a similar velocity profile. The distributions of the boundary layer properties in the scroll correspond well to those of the flow properties at the nozzle. The behavior of the boundary layer in the scroll is found to affect the circumferential nonuniformity of the nozzle flow field.

Hara, K.; Furukawa, M.; Inoue, M. (Kyushu Univ., Fukuoka (Japan). Dept. of Energy and Mechanical Engineering)

1994-07-01

442

Determination of nanogram per liter concentrations of volatile organic compounds in water by capillary gas chromatography and selected ion monitoring mass spectrometry and its use to define groundwater flow directions in Edwards Aquifer, Texas  

USGS Publications Warehouse

A method has been developed to measure nanogram per liter amounts of selected volatile organic compounds (VOCs) including dichlorodifluoromethane, trichlorofluoromethane, cis-1,2-dichloroethene, trichloroethene, tetrachloroethene, and the isomers of dichlorobenzene in water. The method uses purge-and-trap techniques on a 100 mL sample, gas chromatography with a megabore capillary column, and electron impact, selected ion monitoring mass spectrometry. Minimum detection levels for these compounds ranged from 1 to 4 ng/L in water. Recoveries from organic-free distilled water and natural groundwater ranged from 70.5% for dichlorodifluoromethane to 107.8% for 1,4-dichlorobenzene. Precision was generally best for cis-1,2-dichloroethene, tetrachloroethene, and the dichlorobenzene isomers and worst for dichlorodifluoromethane and trichlorofluoromethane. Blank data indicated persistent, trace-level introduction of dichlorodifluoromethane, 1,4-dichlorobenzene, and tetrachloroemene to samples during storage and shipment at concentrations less than the method reporting limits. The largest concentrations of the selected VOCs in 27 water samples from the Edwards aquifer near San Antonio, TX, were from confined-zone wells near an abandoned landfill. The results defined a zone of water with no detectable VOCs in nearly all of the aquifer west of San Antonio and from part of the confined zone beneath San Antonio.

Buszka, P.M.; Rose, D.L.; Ozuna, G.B.; Groschen, G.E.

1995-01-01

443

Enzyme amplification as detection tool in continuous-flow systems. II. On-line coupling of liquid chromatography to enzyme-amplified biochemical detection after pre-column derivatization with biotin.  

PubMed

Enzyme-amplified biochemical detection (EA-BCD) was used as a post-column detection technique, coupled on-line with high-performance liquid chromatography (HPLC). The enzyme detection system was developed to detect biotin or biotin containing compounds. Biotinylation is widely used to label analytes of interest ranging from small molecules to proteins and DNA. Naphthalene aldehyde and anthracene aldehyde were used as model compounds. Both compounds were biotinylated off-line with biotin aminocaproic hydrazide (BACH). On-column biotinylation was performed by preconcentration of anthracene aldehyde on copper phthalocyanine. After biotinylation, samples were introduced to the HPLC system. Enzyme-labeled streptavidin, which possesses high affinity to biotin, was added post-column to the HPLC effluent. Excess of enzyme-labeled affinity protein was removed by means of an immobilized biotin column. After separation of free and bound fraction, substrate was added, which was converted to a fluorescent product by the enzyme label. Using alkaline phosphatase as an enzyme label, a mass detection limit after on-column preconcentration and biotinylation of 250 fmol was achieved. PMID:10519083

van Bommel, M R; de Jong, A P; Tjaden, U R; Irth, H; van der Greef, J

1999-09-10

444

Radial velocity studies of cool stars.  

PubMed

Our current view of exoplanets is one derived primarily from solar-like stars with a strong focus on understanding our Solar System. Our knowledge about the properties of exoplanets around the dominant stellar population by number, the so-called low-mass stars or M dwarfs, is much more cursory. Based on radial velocity discoveries, we find that the semi-major axis distribution of M dwarf planets appears to be broadly similar to those around more massive stars and thus formation and migration processes might be similar to heavier stars. However, we find that the mass of M dwarf planets is relatively much lower than the expected mass dependency based on stellar mass and thus infer that planet formation efficiency around low-mass stars is relatively impaired. We consider techniques to overcome the practical issue of obtaining good quality radial velocity data for M dwarfs despite their faintness and sustained activity and emphasize (i) the wavelength sensitivity of radial velocity signals, (ii) the combination of radial velocity data from different experiments for robust detection of small amplitude signals, and (iii) the selection of targets and radial velocity interpretation of late-type M dwarfs should consider H? behaviour. PMID:24664922

Jones, Hugh R A; Barnes, John; Tuomi, Mikko; Jenkins, James S; Anglada-Escude, Guillem

2014-04-28

445

Radial interchange motions of plasma filaments  

SciTech Connect

Radial convection of isolated filamentary structures due to interchange motions in magnetized plasmas is investigated. Following a basic discussion of vorticity generation, ballooning, and the role of sheaths, a two-field interchange model is studied by means of numerical simulations on a biperiodic domain perpendicular to the magnetic field. It is demonstrated that a blob-like plasma structure develops dipolar vorticity and electrostatic potential fields, resulting in rapid radial acceleration and formation of a steep front and a trailing wake. While the dynamical evolution strongly depends on the amount of collisional diffusion and viscosity, the structure travels a radial distance many times its initial size in all parameter regimes in the absence of sheath dissipation. In the ideal limit, there is an inertial scaling for the maximum radial velocity of isolated filaments. This velocity scales as the acoustic speed times the square root of the structure size relative to the length scale of the magnetic field. The plasma filament eventually decelerates due to mixing and collisional dissipation. Finally, the role of sheath dissipation is investigated. When included in the simulations, it significantly reduces the radial velocity of isolated filaments. The results are discussed in the context of convective transport in scrape-off layer plasmas, comprising both blob-like structures in low confinement modes and edge localized mode filaments in unstable high confinement regimes.

Garcia, O. E.; Bian, N. H.; Fundamenski, W. [Association EURATOM-Risoe National Laboratory, P.O. Box 49, OPL-128 Risoe, DK-4000 Roskilde (Denmark); School of Physics and Astronomy, University of Manchester, Manchester M60 1QD (United Kingdom); EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

2006-08-15

446

The structure of tip clearance flow in axial flow compressors  

Microsoft Academic Search

Detailed measurements of the flow field in the tip region of an axial flow compressor rotor were carried out using a rotating five-hole probe. The axial, tangential, and radial components of relative velocity, as well as the static and stagnation pressures, were obtained at two axial locations, one at the rotor trailing edge, the other downstream of the rotor. The

B. Lakshminarayana; M. Zaccaria; B. Marathe

1995-01-01

447

The Usefulness of Proximal Radial Motor Conduction in Acute Compressive Radial Neuropathy  

PubMed Central

Background and Purpose The objective of this study was to determine diagnostic and prognostic values of proximal radial motor conduction in acute compressive radial neuropathy. Methods Thirty-nine consecutive cases of acute compressive radial neuropathy with radial conduction studies-including stimulation at Erb's point-performed within 14 days from clinical onset were reviewed. The radial conduction data of 39 control subjects were used as reference data. Results Thirty-one men and eight women (age, 45.2±12.7 years, mean±SD) were enrolled. All 33 patients in whom clinical follow-up data were available experienced complete recovery, with a recovery time of 46.8±34.3 days. Partial conduction block was found frequently (17 patients) on radial conduction studies. The decrease in the compound muscle action potential area between the arm and Erb's point was an independent predictor for recovery time. Conclusions Proximal radial motor conduction appears to be a useful method for the early detection and prediction of prognosis of acute compressive radial neuropathy.

Kim, Kun Hyun; Park, Kee-Duk; Chung, Pil-Wook; Moon, Heui-Soo; Kim, Yong Bum; Yoon, Won Tae

2015-01-01

448

Sample injector for high pressure liquid chromatography  

DOEpatents

Apparatus and method for driving a sample, having a well-defined volume, under pressure into a chromatography column. A conventional high pressure sampling valve is replaced by a sample injector composed of a pair of injector components connected in series to a common junction. The injector components are containers of porous dielectric material constructed so as to provide for electroosmotic flow of a sample into the junction. At an appropriate time, a pressure pulse from a high pressure source, that can be an electrokinetic pump, connected to the common junction, drives a portion of the sample, whose size is determined by the dead volume of the common junction, into the chromatographic column for subsequent separation and analysis. The apparatus can be fabricated on a substrate for microanalytical applications.

Paul, Phillip H. (Livermore, CA); Arnold, Don W. (Livermore, CA); Neyer, David W. (Castro Valley, CA)

2001-01-01

449

Dispersion-free radial transmission lines  

DOEpatents

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.

Caporaso, George J. (Livermore, CA); Nelson, Scott D. (Patterson, CA)

2011-04-12

450

High-performance temperature-programmed microfabricated gas chromatography columns  

Microsoft Academic Search

This paper reports the first development of high-performance, silicon-glass micro-gas chromatography (?GC) columns having integrated heaters and temperature sensors for temperature programming, and integrated pressure sensors for flow control. These 3-m long, 150-?m wide and 250-?m deep columns, integrated on a 3.3 cm square die, were fabricated using a silicon-on-glass dissolved wafer process. Demonstrating the contributions to heat dissipation from

Masoud Agah; Joseph A. Potkay; Gordon Lambertus; Richard Sacks; Kensall D. Wise

2005-01-01

451

Determination of selenoethionine by flow injection-hydride generation-atomic absorption spectrometry\\/high-performance liquid chromatography-hydride generation-high power nitrogen microwave-induced plasma mass spectrometry  

Microsoft Academic Search

A simple direct flow injection hydride generation atomic absorption spectrometric method was developed using sodium tetrahydroborate and hydrochloric acid for the determination of selenoethonine (Seet) that excluded any chemical pretreatment prior to hydride generation. The detection limit (3? of blank) of the method was 0.25ngml?1 selenium (standard solutions in Milli-Q water). The reproducibility (R.S.D. of three analyses performed on three

Amit Chatterjee; Y Shibata; A Tanaka; M Morita

2001-01-01

452

The radial pulsation of AI Aurigae  

E-print Network

We present an analysis of eleven years of Stromgren by photometry of the red semiregular variable star AI Aurigae. An early period determination of 63.9 days is confirmed by the long-term light curve behaviour. The light curve shows semi-regular changes with a mean period of 65 days reaching an amplitude of 0.6 mag in some cycles. The b-y colour changes perfectly parallel the V light curve, suggesting radial oscillation to be the main reason for the observed variations. We estimate the main characteristics of the star (mass, radius, effective temperature) that suggest radial pulsation in fundamental or first overtone mode.

L. L. Kiss; B. A. Skiff

2001-02-13

453

Ultrasonic scanner for radial and flat panels  

NASA Technical Reports Server (NTRS)

An ultrasonic scanning mechanism is described that scans panels of honeycomb construction or with welded seams. It incorporates a device which by simple adjustment is adapted to scan either a flat panel or a radial panel. The supporting structure takes the form of a pair of spaced rails. An immersion tank is positioned between the rails and below their level. A work holder is mounted in the tank and is adapted to hold the flat or radial panel. A traveling bridge is movable along the rails and a carriage is mounted on the bridge.

Spencer, R. L.; Hill, E. K. (inventors)

1973-01-01

454

The radial velocity search for extrasolar planets  

NASA Technical Reports Server (NTRS)

Radial velocity measurements are being made to search for planets orbiting stars other than the Sun. The reflex acceleration induced on stars by planets can be sensed by measuring the small, slow changes in the line-of-site velocities of stars. To detect these planetary perturbations, the data series must be made on a uniform instrumental scale for as long as it takes a planet to orbit its star. A spectrometer of extreme stability and unprecedented sensitivity to changes in stellar radial velocities was operated.

Mcmillan, Robert S.

1991-01-01

455

Radial Elasticity of Multiwalled Carbon Nanotubes  

NASA Astrophysics Data System (ADS)

We report an experimental and a theoretical study of the radial elasticity of multiwalled carbon nanotubes as a function of external radius. We use atomic force microscopy and apply small indentation amplitudes in order to stay in the linear elasticity regime. The number of layers for a given tube radius is inferred from transmission electron microscopy, revealing constant ratios of external to internal radii. This enables a comparison with molecular dynamics results, which also shed some light onto the applicability of Hertz theory in this context. Using this theory, we find a radial Young modulus strongly decreasing with increasing radius and reaching an asymptotic value of 30±10 GPa.

Palaci, I.; Fedrigo, S.; Brune, H.; Klinke, C.; Chen, M.; Riedo, E.

2005-05-01

456

Plant analysis 2008--planar chromatography.  

PubMed

For 70 years, planar chromatography has been closely connected with the analysis of plants. Also today in its most advanced form "high performance thin-layer chromatography" (HPTLC), the technique plays an important role in identification of medicinal plants and dietary supplements. Detection of adulteration and quantitative determination of marker substances are other widely used applications. The advancement of instrumentation and methodological concepts has created a basis for reliable qualitative and quantitative results in HPTLC. Remarkable progress has been made in the manageability of the entire planar chromatographic process, particularly in the control of chromatogram development and the utilization of images to obtain and compare information about separated samples. Integration of biological detection systems as well as hyphenation to mass spectrometry has widened the applicability of planar chromatography as an analytical technique that is both orthogonal and complementary to HPLC. PMID:19101887

Reich, Eike; Widmer, Valeria

2009-06-01

457

The Stationary Condensation and Radial Outflow of a Liquid Film on a Horizontal Disk  

NASA Technical Reports Server (NTRS)

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.

Bolshinskiy, Leonid; Frenkel, Alexander

2008-01-01

458

Visualization study of flow in axial flow inducer.  

NASA Technical Reports Server (NTRS)

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.

Lakshminarayana, B.

1972-01-01

459

Isolation of ribosomes by chromatography.  

PubMed

Mixed-mode chromatography on cysteine-SulfoLink resin efficiently separates ribosomes from cell lysates and is particularly effective at rapidly removing endogenous proteases and nucleases, resulting in ribosomes of improved purity, integrity, and activity. Binding occurs partly by anion exchange of the RNA of the ribosomes, so that cells must be lysed in a buffer of moderate ionic strength (conductivity no more than 20 mS for chromatography of bacterial ribosomes) without any highly charged additives (e.g., heparin, which is used to inhibit RNases in yeast). A robust protocol for Escherichia coli is given here as an example. PMID:25834264

Maguire, Bruce A

2015-01-01

460

Extraction chromatography: Progress and opportunities  

SciTech Connect

Extraction chromatography provides a simple and effective method for the analytical and preparative-scale separation of a variety of metal ions. Recent advances in extractant design, particularly the development of extractants capable of metal ion recognition or of strong complex formation in highly acidic media, have significantly improved the utility of the technique. Advances in support design, most notably the introduction of functionalized supports to enhance metal ion retention, promise to yield further improvements. Column instability remains a significant obstacle, however, to the process-scale application of extraction chromatography. 79 refs.

Dietz, M.L.; Horwitz, E.P.; Bond, A.H. [Argonne National Lab., IL (United States). Chemistry Div.

1997-10-01