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1

Dendreon DACS-SC Buoyant Density Solution 60  

Center for Biologics Evaluation and Research (CBER)

Text Version... of BDS60 solution in recovery of_CD34+ cells was evaluated in autologous, mobilized PBPC products obtained from women with breast cancer ... More results from www.fda.gov/downloads/biologicsbloodvaccines/bloodbloodproducts

2

Technology evaluation: APC-8015, Dendreon.  

PubMed

Dendreon (formerly Activated Cell Therapy), in association with the Mayo Clinic, is developing the dendritic cell therapy APC-8015 (Provenge) for the potential treatment of hormone-refractory prostate cancer [284376]. Phase III trials were initiated in January 2000 [353557], and in July 2001 Dendreon anticipated that preliminary results would be available by the end of the year [417283], [427591]. As of September 2001, Dendreon was planning tofile a BLA in 2002 [421356]. Provenge involves the use of a proprietary recombinant antigen derived from prostatic acid phosphatase, found in approximately 95% of prostate cancers. The target antigen is combined with the patient's own dendritic cells and reinfused into the patient to stimulate an immune response [406383]. In November 1999, Dendreon received US-05976546, which covers the composition of the prostate tumor antigen engineered by Dendreon to help stimulate the immune system [347885]. In August 2000, Dendreon received US-06080409, entitled 'Immunostimulatory composition', which relates to the method by which Dendreon's vaccines stimulate the T-cell arm of the immune system tofight cancer [379085]. In April 2001, Dendreon was awarded US-06210662 covering the therapeutic composition of APC-8015 [406383]. PMID:11883698

Rini, Brian I

2002-02-01

3

Serpentine Buoyant Cable Antenna.  

National Technical Information Service (NTIS)

The present invention relates to an improved buoyant cable antenna system. The system includes a buoyant cable transmission line segment and an antenna segment formed from a flexible memory structure comprised of at least one segment of coiled compression...

E. M. Gerhard

2006-01-01

4

Sipuleucel-T: APC 8015, APC-8015, prostate cancer vaccine--Dendreon.  

PubMed

Sipuleucel-T [APC 8015, Provenge] is an autologous, dendritic cell-based vaccine under development with Dendreon Corporation for the treatment of androgen-independent and androgen-dependent prostate cancer. It was generated using the company's active immunotherapy platform to stimulate a patient's own immune system to specifically target and destroy cancer cells, while leaving healthy cells unharmed. This approach could provide patients with a meaningful survival benefit and an improved tolerability profile over existing anticancer therapies. Sipuleucel-T selectively targets the prostate-specific antigen (PSA) known as prostatic acid phosphatase (PAP) that is expressed in approximately 95% of prostate cancers. It is produced by ex vivo exposure of dendritic cell precursors to PA 2024, a recombinant fusion protein composed of the PAP target fused to granulocyte-macrophage colony-stimulating factor (GM-CSF) and incorporated into Dendreon's proprietary Antigen Delivery Cassette. Patients are typically administered three intravenous (IV)-infusions of the vaccine over a 1-month period as a complete course of therapy. It is undergoing late-stage clinical evaluation among patients with early and advanced prostate cancer. In November 2003, Kirin Brewery returned to Dendreon the full rights to Sipuleucel-T for Asia. In exchange, Dendreon licensed patent rights relating to the use of certain HLA-DR antibodies to Kirin for $US20 million. This amended agreement enables Dendreon to complete ongoing discussions for a worldwide marketing and sales partnership for Sipuleucel-T. Similarly, Kirin is able to develop its HLA-DR monoclonal antibodies free of potential infringement claims arising from Dendreon's patent rights to HLA-DR. The licensing agreement relates to patent rights owned by Dendreon relating to monoclonal antibodies against the HLA-DR antigen. In addition, Dendreon retains rights to develop and commercialise its two existing HLA-DR monoclonal antibodies, DN 1921 and DN 1924, as well as other HLA-DR antibodies not being developed by Kirin. Previously, in May 1999, Dendreon and Kirin established a collaboration for the development of dendritic cell-based immunotherapeutics for cancer, including Sipuleucel-T. Under the agreement, Kirin would provide financial support for Dendreon's research on dendritic cells focused on developing immunotherapies for cancers most prevalent in Asia. Dendreon would retain US rights to products arising from the collaboration while Kirin would hold the rights to such immuno-therapeutics in Asia and Oceania. In August 2005, Dendreon signed an agreement to lease a commercial manufacturing facility in Hanover, New Jersey, USA. The company intends to develop the facility to meet anticipated clinical and commercial demands of Sipuleucel-T as well as other active immunotherapy product candidates. Dendreon and Diosynth Biotechnology (Akzo Nobel) have an agreement for the commercial production of the PA 2024 antigen component of Sipuleucel-T. In November 2003, Dendreon announced that Diosynth successfully manufactured PA 2024 on a commercial scale. In October 2001, Dendreon announced that Gambro Healthcare Inc. would provide a network of centres for cell collection to support commercial production and clinical development of various Dendreon vaccines, including Sipuleucel-T. Dendreon has outsourced its cell processing operations in Mountain View, California, USA to Progenitor Cell Therapy under an amended agreement signed in August 2002. This agreement is an expansion of an existing agreement, under which Progenitor provided Dendreon with cell-processing services through its facility in Hackensack, New Jersey, USA. The pivotal, two-stage, phase III trial (D9902 study) has been initiated at clinical sites in the US. The first stage of the trial (D9902A study) is a double-blind, placebo-controlled phase III trial designed to evaluate Sipuleucel-T in men with asymptomatic, metastatic, androgen-independent prostate cancer. The trial was originally designed to be the companion study to a previously completed

2006-01-01

5

Low Loss Buoyant Coaxial Cable.  

National Technical Information Service (NTIS)

A low loss buoyant coaxial cable has its buoyant material placed between its conductors to allow for maximum cable cross section for electrical transmission. In addition, the strength members are placed radially inward of the center conductor to reduce we...

K. F. Hafner

1982-01-01

6

Negatively buoyant starting jets  

NASA Astrophysics Data System (ADS)

The initial development of negatively buoyant jets has been investigated experimentally and numerically, focusing on the role played by gravity in the evolution of the leading vortex ring. Under the experimental conditions considered in this work, the densimetric Froude number, Fr=?jUj2/[(?0-?j)gD], which represents the ratio between the jet momentum and the buoyancy forces, emerges as the most relevant parameter characterizing the dynamics of the flow. Two different flow regimes have been observed depending on the Froude number: for sufficiently small Fr, the vortex ring generated initially is pushed radially away by gravity forces before it has time to detach from the shear layer originating at the orifice. On the other hand, when the Froude number is larger than a critical value, Fr>Frc~1, the vortex ring detaches from the injection orifice and propagates downstream into the stagnant ambient followed by a trailing jet until it eventually reaches a maximum penetration depth. In order to clarify the mechanisms leading to the transition between the two regimes, and to gain physical understanding of the formation dynamics of negatively buoyant starting jets, the total and the vortex circulation, as well as the trajectory of the vortex center, have been measured and compared to the case of neutrally buoyant jets. Finally, based on the experimental measurements and on the results of the numerical computations, a kinematic model that successfully describes the evolution of both total circulation and vortex trajectory is proposed.

Marugán-Cruz, C.; Rodríguez-Rodríguez, J.; Martínez-Bazán, C.

2009-11-01

7

Buoyant plume calculations  

SciTech Connect

Smoke from raging fires produced in the aftermath of a major nuclear exchange has been predicted to cause large decreases in surface temperatures. However, the extent of the decrease and even the sign of the temperature change, depend on how the smoke is distributed with altitude. We present a model capable of evaluating the initial distribution of lofted smoke above a massive fire. Calculations are shown for a two-dimensional slab version of the model and a full three-dimensional version. The model has been evaluated by simulating smoke heights for the Hamburg firestorm of 1943 and a smaller scale oil fire which occurred in Long Beach in 1958. Our plume heights for these fires are compared to those predicted by the classical Morton-Taylor-Turner theory for weakly buoyant plumes. We consider the effect of the added buoyancy caused by condensation of water-laden ground level air being carried to high altitude with the convection column as well as the effects of background wind on the calculated smoke plume heights for several fire intensities. We find that the rise height of the plume depends on the assumed background atmospheric conditions as well as the fire intensity. Little smoke is injected into the stratosphere unless the fire is unusually intense, or atmospheric conditions are more unstable than we have assumed. For intense fires significant amounts of water vapor are condensed raising the possibility of early scavenging of smoke particles by precipitation. 26 references, 11 figures.

Penner, J.E.; Haselman, L.C.; Edwards, L.L.

1985-01-01

8

Buoyant formation number of a starting buoyant jet  

NASA Astrophysics Data System (ADS)

Understanding the influence of buoyancy on the formation number is important for analyzing the development of a starting buoyant jet and the interactions between its vortex ring and trailing stem. Numerical simulations with a large-eddy simulation model are performed to reproduce the starting buoyant jet in conditions ranging from pure jet to lazy plume. From the results, an improved method to determine the formation number is proposed based on the occurrence of a step jump in the vortex ring circulation. A comparison of the numerical results with the experimental data for a starting pure jet is first performed. The widely accepted formation number (~4.0) is obtained, which implies that the method is satisfactory. The effect of buoyancy on the formation number is then investigated for two turbulent discharge conditions of Re=2000 and 2500 and with a wide range of buoyancy flux. Best-fit results are obtained that correlate the formation number with the Richardson number. Finally, a slug model that incorporates buoyancy is developed to allow prediction of the ``buoyant formation number'' for the starting buoyant jet using a limiting value of 0.33 for the dimensionless energy, which is the same value for a pure jet.

Wang, Ruo-Qian; Law, Adrian Wing-Keung; Adams, E. Eric; Fringer, Oliver B.

2009-12-01

9

The Structure of Round Buoyant Turbulent Plumes  

Microsoft Academic Search

An experimental and theoretical study of round buoyant turbulent plumes in still and unstratified environment was conducted, emphasizing self-preserving conditions. The experiments involved downward flowing round negatively -buoyant turbulent plumes created by injecting carbon dioxide and sulfur hexafluoride into still and unstratified air. The mixture fraction and velocity properties were measured using laser-induced iodine fluorescence (LIF) and laser -Doppler velocimetry

Zhongtao Dai

1995-01-01

10

Characteristics of a surface buoyant jet  

Microsoft Academic Search

Tidal outflow from Leschenault Estuary in winter forms an unsteady surface buoyant jet in Koombana Bay on each outgoing tide. As the water moves away from the exit channel and spreads radially over the bay, it assumes a plumelike nature. The mean features of this buoyant outflow, such as the plume shape, frontal celerity, internal circulation, and the bulk entrainment,

David A. Luketina; Jörg Imberger

1987-01-01

11

Buoyant member riser tensioner method and apparatus  

SciTech Connect

A method is described of supporting the weight of an elongated vertical marine riser in a body of water by use of a buoyant member having a vertical slot defined longitudinally therethrough. The buoyant member positioned within a vertical opening is defined through a floating platform and is capable of vertical movement therein. The floating platform is provided with: riser assembly and support means for assembly of the riser and support of the weight of the riser, and buoyancy adjustment means for adjustment of the buoyancy of the buoyant member by the addition to and removal of buoyancy means from the buoyant member, the marine riser provided with: connection means at its lower end for connection of the lower end to subsea equipment fixedly anchored to the seafloor of the body of water, and landing shoulder means connected to the upper portion of the riser having an outer dimension greater than the width of the vertical slot of the buoyant member.

Petersen, W.H.

1987-04-14

12

Transport and Diffusion of Buoyant Material.  

National Technical Information Service (NTIS)

Transport and diffusion of dust and nonbuoyant smokes are simulated realistically by the particle model originally developed at the US Army Atmospheric Sciences Laboratory by Ohmstede and Stenmark. A new and simple algorithm accounts for buoyant smokes an...

J. L. Cogan

1983-01-01

13

Experimental Study of Negatively Buoyant Flows Generated in Enclosure Fires.  

National Technical Information Service (NTIS)

An experimental investigation of the nature of the velocity and thermal fields in negatively buoyant flows generated in enclosure fires is carried out. The flow configuration considered is that of a negatively buoyant two-dimensional jet discharged adjace...

Y. Jaluria D. Goldman

1985-01-01

14

The Rise of Moist, Buoyant Plumes  

Microsoft Academic Search

The governing equations for a moist, buoyant plume in a cross wind are presented. A comparison of the energy equations for saturated and unsaturated plumes, the subject of some previous controversy, shows that the form of the two equations is identical only when the saturated plume is in a saturated atmosphere. In this case, the moist adiabatic lapse rate replaces

Jeffrey C. Weil

1974-01-01

15

Simplified analysis of surface buoyant jet  

Microsoft Academic Search

An examination and analysis of the conservation equations for a surface jet of buoyant fluid in a cross-flow has enabled a simple exposition to be made of the flow. In the near region close to the source the entrainment rate is linear so the mean temperature is inversely proportional to the distance from a virtual source. The rate of entrainment

A. Natalizio; W. D. Baines

1977-01-01

16

Experiments on a Round Turbulent Buoyant Plume.  

National Technical Information Service (NTIS)

This paper reports a comprehensive set of hot-wire measurements of a round buoyant plume which was generated by forcing a jet of hot air vertically up into quiescent environment. The boundary conditions of the experiment were measured, and are documented ...

A. Shabbir W. K. George

1992-01-01

17

MERGING BUOYANT JETS IN A STRATIFIED CROSSFLOW  

EPA Science Inventory

Some of the results of an extensive series of experiments to study the characteristics of merging, horizontally discharged buoyant jets in a linearly density stratified current are summarized. The experiments were conducted in a towing tank to simulate conditions typical of ocean...

18

EXPERIMENTS ON BUOYANT PLUME DISPERSION IN A LABORATORY CONVENTION TANK  

EPA Science Inventory

Buoyant plume dispersion in the convective boundary layer (CBL) is investigated experimentally in a laboratory convection tank. The focus is on highly-buoyant plumes that loft near the CBL capping inversion and resist downward mixing. Highly- buoyant plumes are those with dimen...

19

BUOYANT ADVECTION OF GASES IN UNSATURATED SOIL  

PubMed Central

In unsaturated soil, methane and volatile organic compounds can significantly alter the density of soil gas and induce buoyant gas flow. A series of laboratory experiments was conducted in a two-dimensional, homogeneous sand pack with gas permeabilities ranging from 110 to 3,000 darcy. Pure methane gas was injected horizontally into the sand and steady-state methane profiles were measured. Experimental results are in close agreement with a numerical model that represents the advective and diffusive components of methane transport. Comparison of simulations with and without gravitational acceleration permits identification of conditions where buoyancy dominates methane transport. Significant buoyant flow requires a Rayleigh number greater than 10 and an injected gas velocity sufficient to overcome dilution by molecular diffusion near the source. These criteria allow the extension of laboratory results to idealized field conditions for methane as well as denser-than-air vapors produced by volatilizing nonaqueous phase liquids trapped in unsaturated soil.

Seely, Gregory E.; Falta, Ronald W.; Hunt, James R.

2010-01-01

20

The dynamics of buoyant, rotational river plumes  

NASA Astrophysics Data System (ADS)

River plumes are an important and dynamic component of the coastal landscape, delivering nutrients, contaminants, marine organisms, and sediments to shelf waters and shaping habitats that support some of the most diverse and productive ecosystems on earth. In this dissertation, I address the following question. In large-scale rotational plumes, what determines the flux of river water away from the river mouth? Evidence from satellite and field data suggests that many river plumes exhibit a regime in which an anticyclonic bulge forms at the mouth. This regime has been reproduced in a number of numerical studies forced only by a steady, buoyant inflow. In these models the bulge is identified as an unsteady feature that accumulates a fraction of the inflowing river water, thereby decreasing the transport of river water along the coast. I conduct experiments on a 2-meter rotating table, combining Digital Particle Image Velocimetry (DPIV) and Planar Laser Induced Fluorescence (PLIF) to obtain simultaneous measurements of density and velocity in an idealized buoyant plume. The goal of these experiments is to understand how the structure of the anticyclonic bulge depends on the relative strength of buoyant and rotational forcing of the plume and to determine how they modify the transport away from the river mouth in the coastal current. The results of these experiments provide three principal contributions to the understanding of river plume dynamics. First, they confirm that the unsteady plume structure observed in numerical models is an accurate description of an idealized buoyant rotational plume. Second, they define time dependent scales for the radius and depth of the bulge and show that they are consistent with the observed reduction in coastal current transport. The bulge radius and depth are characterized by inertial and geostrophic scales, respectively. Third, they demonstrate that the structure and alongshore transport in river plumes are strongly modified by the inflow angle and that plumes with low inflow angles are steady.

Horner-Devine, Alexander R.

21

The Structure of Round Buoyant Turbulent Plumes.  

NASA Astrophysics Data System (ADS)

An experimental and theoretical study of round buoyant turbulent plumes in still and unstratified environment was conducted, emphasizing self-preserving conditions. The experiments involved downward flowing round negatively -buoyant turbulent plumes created by injecting carbon dioxide and sulfur hexafluoride into still and unstratified air. The mixture fraction and velocity properties were measured using laser-induced iodine fluorescence (LIF) and laser -Doppler velocimetry (LDV), respectively, while the combined mixture fraction/velocity properties were measured using combined LIF/LDV. The present measurements were exploited to evaluate k-varepsilon-g and Reynolds stress models of buoyant turbulent flows, by direct comparisons between model approximations and measurements. In addition, predictions of the models for the self-preserving region of round buoyant turbulent plumes were compared with measurements in order to assess overall model performance. The self-preserving conditions of round buoyant turbulent plumes were observed relatively far from the source under the present test conditions: rm (x - x_0)/d = 87~151 and rm (x - x_0)/{it l}_ {M} =12~43. Present measurements yielded distributions of mean mixture fractions and streamwise velocities in the self-preserving region that were up to 40% narrower, with appropriately scaled values near the axis up to 30% larger than earlier measurements in the literature, indicating that the earlier measurements actually involved transitional plumes. Large mixture fraction fluctuations and turbulence mass fluxes were observed in the self-preserving region due to the strong correlation between mixture fraction and velocity fluctuations. However, present measurements of velocity fluctuations and the Reynolds stress were similar to round nonbuoyant turbulent jets. Other properties reported include: probability density functions and temporal power spectral densities of mixture fraction and velocity fluctuations, integral time and length scales, two-point correlations of mixture fractions, and high-order moments of velocities and combined mixture fraction/velocity statistics. In addition, turbulence kinetic energy dissipation, mixture fraction variance dissipation, pressure/strain and pressure/mixture -fraction-fluctuation-gradient correlations were obtained from budget analysis. Evaluations of the widely used k-varepsilon -g turbulence model revealed that while mean properties were predicted reasonably well, there were deficiencies of corresponding turbulence properties. For example, streamwise turbulence and momentum fluxes exhibited countergradient diffusion. In addition, the turbulent Prandtl/Schmidt number, the ratio of the characteristic velocity and mixture fraction time scales and the coefficient of the radial gradient diffusion approximation for the Reynolds stress, all exhibited variations across the flow rather than remaining constant as prescribed by k-varepsilon -g model. Evaluations of the Reynolds stress model also revealed some deficiencies, especially somewhat poorer predictions of mean properties and a need to improve the model for the pressure/mixture-fraction-fluctuation-gradient correlation.

Dai, Zhongtao

1995-01-01

22

Buoyant plume rise described by a Lagrangian turbulence model  

Microsoft Academic Search

A Lagrangian turbulence model is presented, which describes buoyant turbulence fully consistent with Eulerian budget equations as motion of fluid particles and change of their temperatures. This model is applied to the description of buoyant plume rise. Due to the simulation the turbulent mixing processes between the plume and ambient fluid in dependence on varying ambient conditions, the plume rise

Stefan Heinz; Han van Dop

1999-01-01

23

46 CFR 160.010-5 - Buoyant apparatus with plastic foam buoyancy.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Buoyant apparatus with plastic foam buoyancy. 160.010-5 Section...160.010-5 Buoyant apparatus with plastic foam buoyancy. (a) Buoyant apparatus with plastic foam buoyancy must have a plastic...

2011-10-01

24

46 CFR 160.010-5 - Buoyant apparatus with plastic foam buoyancy.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Buoyant apparatus with plastic foam buoyancy. 160.010-5 Section...160.010-5 Buoyant apparatus with plastic foam buoyancy. (a) Buoyant apparatus with plastic foam buoyancy must have a plastic...

2012-10-01

25

46 CFR 160.010-5 - Buoyant apparatus with plastic foam buoyancy.  

Code of Federal Regulations, 2010 CFR

...false Buoyant apparatus with plastic foam buoyancy. 160.010-5 Section 160.010-5...010-5 Buoyant apparatus with plastic foam buoyancy. (a) Buoyant apparatus with plastic foam buoyancy must have a plastic foam body with...

2009-10-01

26

Sumberged buoyant offshore drilling and production tower  

SciTech Connect

A submerged tubular tower is connected at its lower end to an ocean floor at a site where at least one subsea hydrocarbon well is to be drilled. A riser duct for each well to be drilled extends from an upwardly accessible connection point at the upper end of the tower to the lower end of the tower. The tower is positively buoyant to stand erect in an unguyed manner. The upper end of the tower is located a substantial distance above the ocean floor at a depth sufficiently small to enable wells to be drilled through the riser ducts, through equipment landed on the top of the tower, using floating drilling equipment designed for use in substantially shallower water depths.

Horton, E. E.

1985-04-16

27

A turbulence model for buoyant flows based on vorticity generation.  

SciTech Connect

A turbulence model for buoyant flows has been developed in the context of a k-{var_epsilon} turbulence modeling approach. A production term is added to the turbulent kinetic energy equation based on dimensional reasoning using an appropriate time scale for buoyancy-induced turbulence taken from the vorticity conservation equation. The resulting turbulence model is calibrated against far field helium-air spread rate data, and validated with near source, strongly buoyant helium plume data sets. This model is more numerically stable and gives better predictions over a much broader range of mesh densities than the standard k-{var_epsilon} model for these strongly buoyant flows.

Domino, Stefan Paul; Nicolette, Vernon F.; O'Hern, Timothy John; Tieszen, Sheldon R.; Black, Amalia Rebecca

2005-10-01

28

Compressibility effects in some buoyant flows  

NASA Astrophysics Data System (ADS)

Compressibility effects in buoyant flows are studied on three examples: the classical Rayleigh-Taylor instability (RTI) for compressible miscible flows, the ablation front instability and the thermal convection of Rayleigh-Bénard. The linear analysis of the classical RTI for viscous flows is performed and the opposite effects of stratification and compressibility on the growth rate are pointed out. Some investigations in the nonlinear regime have also been carried out and show that the trend observed in the linear regime usually holds. On the other hand, a 2D simulation, started from rest and pursued until the return toward mechanical equilibrium of the mixing exhibits a typical compressibility effect, an acoustic wave, damped by the physical viscosity. The ablation front instability is detailed on the 'laser imprint' problem of direct drive irradiation. The linear stability analysis is performed on an unsteady mean flow given by the self-similar solutions of gas dynamics equations with nonlinear heat conduction. Compressibility effects are studied through the Kovásznay modes. It appears that maximum amplitudes are achieved for zero wave number, and complex wave-like structures are observed. Analogy with the large-scale instability, which occurs in compressible thermal convection, is suggested. These results have been obtained with an autoadaptive dynamical multidomain Chebyshev method.

Gauthier, S.; Lafay, M.-A.; Lombard, V.; Boudesocque-Dubois, C.; Clarisse, J.-M.; LeCreurer, B.

2008-12-01

29

Selection of Buoyant Materials for Deep Submergence Search Vehicle.  

National Technical Information Service (NTIS)

The purpose of the survey and technical analysis is identification and recommendation of four types of buoyant materials, assessment of predicted confidence levels for each material, evaluation of critical factors affecting performance, and recommendation...

J. Irgon W. M. Davidson

1965-01-01

30

Matrix acidizing in Saudi Arabia using buoyant ball sealers  

SciTech Connect

Acid jobs utilizing buoyant ball sealers have been performed on several wells with varied downhole conditions and different productivities. The test objectives were to determine buoyant ball sealer's diverting efficiency when pumping at matrix acidizing rate and to determine whether or not the bouyant ball sealers are more effective than the particulate diverting materials presently being used. Complete pre and post-acidization testing provided accurate data for valid test analysis. The buoyant ball sealers were effective in every test. Matrix acidizing of long intervals and multiple sets of perforations was successfully accomplished. Marked production improvement resulted from a well previously acidized utilizing particulate diverting materials. Production of an old well previously acidized six times was increased to the highest rate in its sixteen year producing history. Buoyant ball sealers are the most effective means of diverting acid when matrix acidizing perforated completions.

Bale, G.E.

1983-03-01

31

Dynamic Stability of Positively Buoyant Submersibles: Vertical Plane Solutions.  

National Technical Information Service (NTIS)

This thesis analyzes the dynamic stability of positively buoyant submersibles. Six degree-of-freedom equations of motion are used to compute steady state behavior with motion restricted to the vertical plane. Steady state solutions are analyzed for variou...

B. D. McKinley

1991-01-01

32

Buoyant Jet Discharge Model: Seabrook Nuclear Station - Unit No. 1, Public Service Company of New Hampshire.  

National Technical Information Service (NTIS)

Hydraulic model studies of the buoyant jet discharge from the proposed Seabrook Nuclear Station, Unit No. 1 are currently underway. A model suitable for studying the buoyant jet discharge has been constructed and equipped with the necessary flow measuring...

P. A. Larsen C. H. Lantz

1969-01-01

33

Buoyant surface jet analysis of the Yukon River  

Microsoft Academic Search

Thermal infrared satellite imagery of the discharge from the Yukon River obtained on 5 July 1985 was compared with hydraulic theory for the dilution of buoyant surface jets. In a crossflow, the theory predicts that the plume will follow an x trajectory where x is distance alongshore, and that the plume temperature will decay according to x due to mixing

J. P. Gosink

1988-01-01

34

FLOWS OF NEUTRALLY BUOYANT SUSPENSIONS IN SEVERAL VISCOMETERS  

Microsoft Academic Search

The theory developed by Jiang et al. (1987) for a flowing suspension of neutrally buoyant spheres in an incompressible Newtonian fluid is further tested for a limiting case of the Couette viscometer, for a limiting case of the cone-plate viscometer, and for the parallel-plate viscometer. Compared with the available data for the Couette viscometer, the average errors are less than

ALFRED C. LI; MICHAEL H. KIM; TSUNG-SHANN JIANG; JOHN C. SLATTERY

1988-01-01

35

Buoyant Ocean Floor and the Evolution of the Caribbean  

Microsoft Academic Search

Ocean floor in the Caribbean was formed mainly during the Jurassic and Cretaceous. Subduction of the young Caribbean ocean floor started by Late Jurassic times and persisted until the Eocene on its northern and southern borders. By the late Eocene the Caribbean area was occupied by a buoyant mass of abnormally thick and shallow oceanic crust modified from more normal

Kevin Burke; P. J. Fox; A. M. C. ?engör

1978-01-01

36

Turbulence and entrainment in a buoyant surface plume  

Microsoft Academic Search

In winter, tidal outflow from the Leschenault Estuary forms a buoyant sheared stratified plume in Koombana Bay on each outgoing tide. The turbulence in the plume and the local entrainment into the plume are examined based on measurements collected in an intensive field program. Coherency measurements between horizontally separated sensors are used to examine the anisotropy of the turbulence. The

David A. Luketina; Jörg Imberger

1989-01-01

37

On a simulator of a buoyant antenna - satellite wireless channel  

Microsoft Academic Search

A model of fading in a buoyant antenna array satellite link is suggested. A random number of active elements is modelled by changes in the Nakagami factor m in a system of randomly switched stochastic differential equations. Analytical solutions are given for the case of slow and fast changes.

Serguei Primak; Jeff Weaver; Valeri Kontorovich

2003-01-01

38

Vertical turbulent buoyant jets: A review of experimental data  

Microsoft Academic Search

Experimental data on vertical turbulent buoyant jets issuing into calm neutral or stably stratified environments are reviewed critically. Both plane and axisymmetric jets are included, and the whole Froude number range from the pure jet to the pure plume is covered. Similarity and scaling laws are introduced and the experimental data are interpreted according to these laws. Measurements of the

C. J. Chen; W. Rodi

1980-01-01

39

The Determination of Formation Number for Starting Buoyant Jets  

NASA Astrophysics Data System (ADS)

Starting buoyant jets are widely observed in nature as well as in engineering applications. The interactions between the leading vortex ring and the trailing stem play a significant role on the development of the staring processes, and the Formation Number is established to be the criterion that demarcates the presence of the trailing stem and thus, the occurrence of pinch-off. In this study, the buoyant formation number for a starting buoyant jet which includes the momentum inducement due to presence of buoyancy is examined numerically. The investigation is based on the results of a series of numerical simulations with the Large-Eddy Simulation (LES) approach to reproduce the starting buoyant jet in a wide range of conditions from pure jets to lazy plumes. Based on the results, the buoyant formation number can be obtained following the occurrence of a step-jump in the vortex ring circulation in the following manner. First, the vorticity is integrated through the half central plane of the computational domain, which a trough can be observed to follow the head vortex ring in the vertical distribution. The trailing stem and the head vortex ring are differentiated based on this trough location. Subsequently, if and just before a pitch off occurs, a step-jump in the circulation of the head vortex ring is typically observed. The jump value is then traced back to the total circulation, and the non-dimensional time that it occurs. This non-dimensional time is found to the same as the formation number for the runs conducted. Using this method, a comparison of the numerical results with the experimental data for a starting pure jet is performed, and the widely accepted formation number (~4.0) is obtained which verifies that the method is satisfactory. The effect of buoyancy on the formation number is then investigated for two turbulent discharge conditions of Re = 2000 and 2500 and with a wide range of buoyancy fluxes.

Wang, Ruo-Qian; Law, Adrian Wing-Keung; Eric Adams, E.; Fringer, Oliver B.

2010-05-01

40

Critical Behavior in Buoyant Melting Instabilities Beneath Extending Lithosphere  

NASA Astrophysics Data System (ADS)

Upwelling mantle beneath extending lithosphere typically undergoes decompression partial melting and is the ultimate source of volcanism in most extensional provinces on Earth. Decompression melting of the upper mantle is associated with a decreased density due to the presence of a small fraction of melt and changes in composition and phase abundance in the rock. Thus if one portion of a partially melting layer ascends at a slightly faster rate, it will produce and retain more melt and as a consequence become less dense than adjacent portions of the layer. This in turn gives rise to a buoyancy surplus in faster upwellings that causes them to ascend even more quickly and produce more melt, thus setting the stage for what we call a "buoyant melting instability," or unstable buoyant overturn within the partially melting region. Using numerical convection models that include thermal expansion, melt retention, and melt depletion buoyancy as well as melt percolation, we study the onset of buoyant melting instabilities in a plane layer of partially melting mantle accompanying diffuse extension of the lithosphere. Buoyant melting instabilities do not always occur during extension, and in some cases only develop after extension has stopped. The occurrence of this "post- extensional" variety of instability depends on the rate of extension, melt percolation, and mantle viscosity as well as the depth-distribution of melt depletion density changes. Using a linear stability analysis, we have derived a "Rayleigh number" for this process with a critical value that accurately describes the occurrence of post-extensional instabilities in the models, and also compares reasonably well with previous studies on the occurrence of buoyant melting instabilities beneath slow-spreading mid-ocean ridges. This theory has potential applications for the observed increase in localized volcanism following Miocene extension in the western United States Basin and Range province as well as the occurrence of spreading-rate dependence in three- dimensional structure along mid-ocean ridges.

Hernlund, J. W.; Stevenson, D. J.; Tackley, P. J.

2006-12-01

41

Numerical 3D simulations of buoyant magnetic flux tubes  

NASA Astrophysics Data System (ADS)

We have examined instabilities of non-thin buoyant magnetic flux tubes ascending through a solar convection zone model using numerical 3D MHD experiments. The experiments show that the fate of the flux tubes is entirely dependent on the internal topology of the magnetic field lines in the flux tube; if the initial topology is too simple the tube is quickly disrupted by a Rayleigh-Taylor like instability. The disruption is prevented or delayed if the field has a component that makes the topology non-trivial. Even a weak random or twisting component, an order of magnitude weaker than the longitudinal magnetic field, is sufficient to let the tube ascend as a more or less coherent structure. These 3D results may resolve the apparent contradiction between the success of experiments using the thin flux tube approximation to study the buoyant rise of magnetic flux tubes, and the rapid break-up of flux tubes found in 2D experiments.

Dorch, S. B. F.; Nordlund, A.

1998-10-01

42

AN ANALYSIS OF THE TWO-DIMENSIONAL TURBULENT BUOYANT JET  

Microsoft Academic Search

The two-dimensional turbulent buoyant jet is analyzed using a vertical length scale defined by L = M0F0  where Ma is the rate at which momentum is added at the source and F0 is the rate at which buoyancy is added. Introduction of the length scales into the equations of motion shows the ratio x\\/L directly controls the bouyancy term. The

C. B. BAKER; A. J. MAFFE; D. B. TAULBEE

1989-01-01

43

Modelling thermal radiation in buoyant turbulent diffusion flames  

Microsoft Academic Search

This work focuses on the numerical modelling of radiative heat transfer in laboratory-scale buoyant turbulent diffusion flames. Spectral gas and soot radiation is modelled by using the Full-Spectrum Correlated-k (FSCK) method. Turbulence-Radiation Interactions (TRI) are taken into account by considering the Optically-Thin Fluctuation Approximation (OTFA), the resulting time-averaged Radiative Transfer Equation (RTE) being solved by the Finite Volume Method (FVM).

J. L. Consalvi; R. Demarco; A. Fuentes

2012-01-01

44

Vorticity and transport in a buoyant, rotational inflow  

NASA Astrophysics Data System (ADS)

We use laboratory experiments to investigate the dynamics of a constant, buoyant inflow in a rotating frame. This flow consists of an anticyclonic gyre, or bulge, that forms against the coast to the right of the inflow and a jet that circumscribes the bulge and eventually forms a coastal current downstream of the bulge. The bulge accumulates a fraction of the inflow, thereby reducing the flux of buoyant fluid away from the source in the coastal current. We focus our investigation, in particular, on how the dynamics of the bulge reduce the coastal transport. This is important to understanding how river-borne nutrients, contaminants and sediments are distributed in coastal zones. We carry out experiments on a 2 meter rotating table combining Particle Image Velocimetry and Laser Induced Fluorescence to obtain simultaneous, high-resolution measurements of density and velocity in an idealized buoyant plume. We show that, in the first 8 rotation periods, the bulge circulation is in an inertial-rotational balance and that buoyancy plays a secondary role. We also find that the bulge vorticity normalized by the rotation frequency is lower for experiments with lower rotation frequency. Finally, we show how the partitioning of vorticity in the plume determines the flux in the coastal current.

Horner-Devine, A.; Fong, D.; Maxworthy, T.; Monismith, S.

2003-04-01

45

Determination of drag coefficients for a buoyant cable antenna  

NASA Astrophysics Data System (ADS)

Samples of buoyant cable antennas of various lengths and surface roughnesses were towed over a range of speeds and depths in different wave conditions. Based on measurements of the forces developed and using computerized prediction techniques, normal and tangential drag coefficients were determined for the submerged segment of the BCA configuration and drag coefficients were determined for the floating length segment. The drag coefficients are presented in both tabular and graphical form. The results indicate that both waves and surface roughness can have a significant effect on the drag coefficients. The results also indicate that the effects of cable stiffness on the accuracy of the cable catenary predictions require further investigation.

Israel, A. M.

1982-03-01

46

Dynamics of finite size neutrally buoyant particles in isotropic turbulence  

NASA Astrophysics Data System (ADS)

The dynamics of neutrally buoyant particles suspended in a turbulent flow is investigated experimentally, with particles having diameters larger than the Kolmogorov length scale. To that purpose, a turbulence generator have been constructed and the resulting flow characterized. The fluid was then seeded with polystyrene particles of diameter about 1 mm and their velocity measured separately and simultaneously with the surrounding fluid. Comparison of the velocities statistics between the two phases shows no appreciable discrepancy. However, simultaneous velocity measurement shows that particles may move in different direction from the underlying flow.

Elhimer, M.; Jean, A.; Praud, O.; Bazile, R.; Marchal, M.; Couteau, G.

2011-12-01

47

Phytoplankton productivity in a turbid buoyant coastal plume  

NASA Astrophysics Data System (ADS)

The complex dynamics associated with coastal buoyant plumes make it difficult to document the interactions between light availability, phytoplankton carbon fixation, and biomass accumulation. Using real-time data, provided by satellites and high frequency radar, we adaptively sampled a low salinity parcel of water that was exported from the Hudson river estuary in April 2005. The water was characterized by high nutrients and high chlorophyll concentrations. The majority of the low salinity water was re-circulated within a nearshore surface feature for 5 days during which nitrate concentrations dropped 7-fold, the maximum quantum yield for photosynthesis dropped 10-fold, and primary productivity rates decreased 5-fold. Associated with the decline in nitrate was an increase in phytoplankton biomass. The phytoplankton combined with the Colored Dissolved Organic Matter (CDOM) and non-algal particles attenuated the light so the 1% light level ranged between 3 and 10 m depending on the age of the plume water. As the plume was 10-15 m thick, the majority of the phytoplankton were light-limited. Vertical mixing within the plume was high as indicated by the dispersion of injected of rhodamine dye. The mixing within the buoyant plume was more rapid than phytoplankton photoacclimation processes. Mixing rates within the plume was the critical factor determining overall productivity rates within the turbid plume.

Schofield, Oscar; Moline, Mark; Cahill, Brownyn; Frazer, Thomas; Kahl, Alex; Oliver, Matthew; Reinfelder, John; Glenn, Scott; Chant, Robert

48

Experimental study on buoyant flow stratification induced by a fire in a horizontal channel  

Microsoft Academic Search

Experiments were carried out in a reduced-scale horizontal channel to investigate the fire-induced buoyant flow stratification behavior, with the effect of the velocity shear between the hot buoyant flow and the cool air flow considered. This shear intensity was controlled and varied by changing the exhaust rate at the ceiling with one of the end of the channel opened. The

D. Yang; L. H. Hu; R. Huo; Y. Q. Jiang; S. Liu; F. Tang

2010-01-01

49

Development of surfaces repelling negatively buoyant solid particles  

NASA Astrophysics Data System (ADS)

Using a hybrid computational method that integrates the lattice Boltzmann model for fluid dynamics and the lattice spring model for solids, we examine the motion of negatively buoyant solid microparticles in shear flow near a solid wall decorated with regularly distributed rigid posts. The posts are arranged in a square pattern and tilted relative to the flow direction. We show that when rigid posts are tilted against flow, secondary flows emerge that prevent the deposition of suspended particles on the solid surface. We probe the effect of post geometry on the development of secondary flows and identify the optimal post architecture in terms of the mass of levitated solid particles. Our results are useful for designing anti-fouling surfaces that repel colloidal particles carried by fluid.

Semmler, Carina; Alexeev, Alexander

2011-03-01

50

Buoyant melting instabilities beneath extending lithosphere: 1. Numerical models  

NASA Astrophysics Data System (ADS)

Buoyant decompression melting instabilities in regions of partially molten upper mantle have been proposed to be an important process that might account for some characteristics of intraplate volcanism on Earth and other terrestrial planets. The instability is driven by variations in the melting rate within a partially molten layer whenever a relative decrease in density accompanies decompression melting of ascending mantle. Here, the development of buoyant decompression melting instabilities in a plane layer of passively upwelling and partially melting mantle beneath diffusely extending lithosphere is studied using numerical convection models covering a wide range of physical parameters. We find that the occurrence and nature of these instabilities in such a scenario is strongly affected by the rate of extension and melt percolation, as well as depth distribution of solid density variations arising from melt depletion. In some cases, instabilities do not occur during extension, but only develop after extension has slowed or stopped completely. This behavior creates two pulses of magma generation due to passive upwelling accompanying extension followed by the subsequent instability and is favored by a faster rate of extension, higher mantle viscosity, higher rate of melt percolation, and smaller amount of solid residuum depletion-derived buoyancy. Larger degrees of solid density changes accompanying melt depletion can enhance the instability of partially molten mantle during extension but decrease the cumulative volume of generated melt. This kind of behavior modifies the conventional expectation of spatially and temporally correlated volcanism and extension and may lend insight into the observed increase in localized volcanic activity following Miocene Basin and Range extension in the western United States.

Hernlund, John W.; Tackley, Paul J.; Stevenson, David J.

2008-04-01

51

Sampling and analysis of particles from buoyant hydrothermal plumes  

NASA Astrophysics Data System (ADS)

The objective of our studies has been to identify the chemical processes that occur in the buoyant part of hydrothermal plumes and to evaluate their role in determining the ultimate fate of the hydrothermal input to the oceans. Our first such effort is described by Mottl and McConachy [1990]. Because the buoyant plume is a small feature that contains very large physical and chemical gradients, we have sampled it from manned submersibles. We have used two different samplers, both manufactured by General Oceanics in Miami: the Go-Flo bottle and the Chopstick sampler. Four Go-Flo bottles of 1.7 L capacity can readily be mounted on most submersibles, vertically and in a forward position in sight of the pilot's viewport and video cameras, without interfering with other operations on a dive. On Alvin they have typically been mounted on the outside starboard edge of the basket. On Turtle they were mounted on the outside edge of the port manipulator. We chose Go-Flo rather than Niskin bottles because the latter are prone to spillage when the rods attached to the end caps are bumped against an object such as the seafloor, as often happens on a submersible dive. Go-Flo bottles are also more easily rigged for pressure filtration than are Niskins. The main disadvantage of Go-Flo bottles vs. Niskins for this application is the internal silicone rubber ring that holds the ball valves in place on each end of the Go-Flo. This ring tends to trap large particles that are then difficult to dislodge and collect. The rings are also difficult to clean between dives.

Mottl, Michael J.

52

Upwelling-driven buoyant plume dynamics in northern Monterey Bay  

NASA Astrophysics Data System (ADS)

Northwesterly winds along the central California coastline lead to the occurrence of a strong upwelling plume that originates at Point Ano Nuevo and flows southward across the mouth of Monterey Bay. Within the bay, solar heating leads to the development of a buoyant water mass often called an upwelling shadow (Graham and Largier 1993), and a convergent front with temperature gradients of up to 7° C over one to a few hundred meters develop between cold upwelling plumes offshore, and warm nearshore waters. This nearshore convergent front is poorly resolved by remote sensing, due to the high frequency of regional cloud and fog cover as well as the failure of remote sensing algorithms near the coast. Oceanographic conditions were monitored using 4 cross-shore mooring arrays consisting of 12 total moorings and hydrographic surveys along a 10-km stretch of coast extending along the central California coast, from the shoreline out to the 60-m isobath during most of the summer upwelling season of 2007 (May - September) in order to evaluate the forcing mechanisms driving the location and movement of this nearshore front and its effects on biological communities in northern Monterey Bay. During the upwelling season, the upwelling shadow front behaved as a coastally- and surface-trapped buoyant feature moving up and down the coast up to several kilometers each day in response to wind forcing. Regional-scale wind relaxation events allowed the warm upwelling shadow waters to move northwestward along the coast, sometimes being completely flushed from the bay, and transporting phytoplankton, larvae, and potentially pollutants up the coast. The presence and location of the front along the coast was driven by regional wind forcing, leading to an alongshore pressure gradient, and local wind forcing (diurnal sea breeze) occurring on daily time scales.

Woodson, C. B.; Barth, J. A.; Hoover, D. J.; Kirincich, A. R.; McManus, M. A.; Ryan, J. P.; Tyburczy, J.; Washburn, L.

2008-12-01

53

Sheathless hydrodynamic positioning of buoyant drops and bubbles inside microchannels  

NASA Astrophysics Data System (ADS)

Particles, bubbles, and drops carried by a fluid in a confined environment such as a pipe can be subjected to hydrodynamic lift forces, i.e., forces that are perpendicular to the direction of the flow. We investigated the positioning effect of lift forces acting on buoyant drops and bubbles suspended in a carrier fluid and flowing in a horizontal microchannel. We report experiments on drops of water in fluorocarbon liquid, and on bubbles of nitrogen in hydrocarbon liquid and silicone oil, inside microchannels with widths on the order of 0.1-1 mm. Despite their buoyancy, drops and bubbles could travel without contacting with the walls of channels; the most important parameters for reaching this flow regime in our experiments were the viscosity and the velocity of the carrier fluid, and the sizes of drops and bubbles. The dependencies of the transverse position of drops and bubbles on these parameters were investigated. At steady state, the trajectories of drops and bubbles approached the center of the channel for drops and bubbles almost as large as the channel, carried by rapidly flowing viscous liquids; among our experiments, these flow conditions were characterized by larger capillary numbers and smaller Reynolds numbers. Analytical models of lift forces developed for the flow of drops much smaller than the width of the channel failed to predict their transverse position, while computational fluid dynamic simulations of the experiments agreed better with the experimental measurements. The degrees of success of these predictions indicate the importance of confinement on generating strong hydrodynamic lift forces. We conclude that, inside microfluidic channels, it is possible to support and position buoyant drops and bubbles simply by flowing a single-stream (i.e., “sheathless”) carrier liquid that has appropriate velocity and hydrodynamic properties.

Stan, Claudiu A.; Guglielmini, Laura; Ellerbee, Audrey K.; Caviezel, Daniel; Stone, Howard A.; Whitesides, George M.

2011-09-01

54

Numerical modeling of chemically buoyant mantle plumes at spreading ridges  

NASA Astrophysics Data System (ADS)

The geometry of spreading of plumes beneath mid-oceanic ridges is investigated by three-dimensional numerical modeling, with the goal of characterizing the width of the plume along the ridge, or the 'waist width'. Chemically buoyant plumes are modeled, in order to compare to previously reported laboratory tank experiments. The plume is generated near the bottom of the box and rises and forms a mushroom-head with some entrainment of surrounding fluid. The head flattens at a considerable depth beneath the ridge before rising to the surface. Once the plume reaches the surface the head is quickly divided by the diverging plates, and the waist width is found to have reached a steady-state value, W. The results show that W is proportional to the square root of the volumetric flux of the plume divided by the diverging plate speed, which is consistent with previously reported experimental data. Our scaling law gives an independent method for estimating the volumetric flux of mantle plumes. The calculated plume fluxes are two to four times larger than previous estimates. If plume buoyancy is purely of thermal origin, then excess temperatures can be estimated from the fluxes. For Iceland, Azores and the Galapagos, the calculated excess temperatures are 140, 57, and 51 C respectively, in agreement with recent, independent estimates from modeling of gravity and bathymetry.

Feighner, Mark A.; Kellogg, Louise H.; Travis, Bryan J.

1995-03-01

55

A piezoelectric, flexural-disk, neutrally buoyant, underwater accelerometer.  

PubMed

A piezoelectric, flexural-disk accelerometer for underwater use is composed of two PZT-5A lead zirconate-titanate disks that are bonded to an aluminum substrate. The substrate is edge-supported inside an aluminum housing. The housing is enclosed in syntactic foam so that the sensor is neutrally buoyant. The overall height is 1.0 in. (26 mm), the overall diameter is 1.9 in. (49 mm), and the total mass is 0.054 kg. With 25 ft (7.6 m) of (230 pF/m) cable attached, the sensitivity is -42 dB re 1 V-s(2)/m (-22 dB re 1 V/g), the capacitance is 5.0 nF, and the resonance frequency is 11 kHz. When used in conjuction with a Micro Networks MN3210 preamplifier, the spectral noise-equivalent acceleration floor is approximately -171 dB re 1 m/s(2)- radicalHz (-151 dB re 1 g/ radicalHz) at 5 kHz. PMID:18244296

Moffett, M B; Trivett, D H; Klippel, P J; Baird, P D

1998-01-01

56

A new Lagrangian method for modelling the buoyant plume rise  

NASA Astrophysics Data System (ADS)

A new method for the buoyant plume rise computation is proposed. Following Alessandrini and Ferrero (Phys A 388:1375–1387, 2009) a scalar transported by the particles and representing the temperature difference between the plume and the environment air is introduced. As a consequence, no more particles than those inside the plume have to be released to simulate the entrainment of the background air temperature. A second scalar, the vertical plume velocity, is assigned to each particle. In this way the entrainment is properly simulated and the plume rise is calculated from the local property of the flow. The model has been tested against data from two laboratory experiments in neutral and stable stratified flows. The comparison shows a good agreement.Then, we tested our new model against literature analytical formulae in a simple uniform neutral atmosphere, considering either the case of a single plume or the one of two plumes from adjacent stacks combining during the rising stage. Finally, a comparison of the model against an atmospheric tracer experiment (Bull Run), characterized by vertically non-homogeneous fields (wind velocity, temperature, velocity standard deviations and time scales), was performed. All the tests confirmed the satisfactory performance of the model.

Alessandrini, Stefano; Ferrero, Enrico; Anfossi, Domenico

2013-10-01

57

Residence time of buoyant objects in drowning machines  

PubMed Central

Hydraulic jumps are a common feature of rivers and waterways, where they can be found close to spillways, weirs, rocky ledges, and boulders. People adrift upstream of a hydraulic jump are liable to become trapped in the turbulent roller of the hydraulic jump. For this reason, hydraulic jumps have been termed “drowning machines” and are recognized as a public hazard. We use experiments and theory to show that on average a buoyant object spends a time ?/p trapped in a jump, where ? is the period of a harmonic process inherent in the jump, and p is the probability that the object will escape in any time interval ?. The probability p is governed by the statistical theory of extreme values and depends primarily on the ratio between the density of the object and the density of the fluid. We use our results to draw conclusions that might prove to be useful to public-safety agencies intent on carrying out tests in drowning machines. Our results can also be used to predict the amount of flotsam that accumulates at the toe of a hydraulic jump.

Gioia, Gustavo; Chakraborty, Pinaki; Gary, Stefan F.; Zamalloa, Carlo Zuniga; Keane, Richard D.

2011-01-01

58

Vehicle Concepts and Technology Requirements for Buoyant Heavy-Lift Systems.  

National Technical Information Service (NTIS)

Several buoyant-vehicle (airship) concepts proposed for short hauls of heavy payloads are described. Numerous studies identified operating cost and payload capacity advantages relative to existing or proposed heavy-lift helicopters for such vehicles. Appl...

M. D. Ardema

1981-01-01

59

46 CFR 160.010-4 - General requirements for buoyant apparatus.  

Code of Federal Regulations, 2011 CFR

...defects in workmanship. (m) Each metal part of a buoyant apparatus must beâ (1) 410 stainless steel or have salt water and salt air corrosion characteristics equal or superior to 410 stainless steel; and (2) Galvanically compatible...

2011-10-01

60

Physical and Numerical Modeling of Buoyant Groundwater Plumes  

NASA Astrophysics Data System (ADS)

In coastal states, the injection of treated wastewater into deep saline aquifers offers a disposal alternative to ocean outfalls and discharge directly into local waterways. The density of treated wastewater is similar to that of freshwater but is often much lower than the ambient density of deep aquifers. This significant density contrast can cause upward buoyant movement of the wastewater plume during and after injection. Since some wastewater treatment plants inject more than 100 MGD of this treated wastewater, it is of the utmost importance to be able to not only determine the fate and transport rates of the plume, but to be able to best determine locations for monitoring wells for early detection of possible problems. In this study, both physical and numerical modeling were undertaken to investigate and understand buoyant plume behavior and transport. Physical models using a 2D cross-sectional Plexiglas tank filled with glass beads were carried out under different ambient density scenarios. The experiments consisted of injection of a freshwater pulse-source bubble into a fully saline tank. The injection occurred in an initially static system with no ambient flow. In the scenarios, the freshwater plume migrated vertically upward until reaching the top of the tank. Fingers developed because of the heterogeneity of the density dependent flow field. The vertical velocities and transport patterns of these plumes were compared to one another to investigate variances due to different ambient water densities. Using the finite-difference numerical code SEAWAT to simulate variable density flow, the experiments were numerically modeled and compared with the physical model results. Due to the sensitivity of this problem to numerical resolution, results from three different grids were compared to determine a reasonable compromise between computer runtimes and numerical accuracy. Furthermore, a comparison of advection solvers was undertaken to identify the best solver to use for this specific problem. This involved a comparison between finite- difference, total variation diminishing and mixed Eulerian-Langrangian methods. From these scenarios, the Method of Characteristics (MOC) advection solver with the fine resolution grid (0.1 cm x 0.1 cm x 2.7 cm cells) resulted in a simulation that was in good agreement with the physical experiments. This model was determined to be the base-case problem for further sensitivity analysis. To further verify both the physical and numerical model, SUTRA_MS was also used for comparison. Dimensionless analysis of the flow and transport governing equations was undertaken to determine important physical problem parameters. From these derived dimensionless numbers, it was hypothesized that density, hydraulic conductivity and dispersivity should all play important roles in this problem. A parameter sensitivity analysis was performed using the numerical model base-case. The parameters investigated were hydraulic conductivity, ambient groundwater density, longitudinal dispersivity and injection volume. It was determined that the problem was most sensitive to ambient density, hydraulic conductivity and dispersivity changes as hypothesized, with all three affecting both vertical mass transfer rates, plume fingering and mixing between the fresh and saline waters. The sensitivity to injection volume was not seen to be an important parameter, except for the obvious effect of change in size of the plume.

Brakefield, L. K.; Abarca, E.; Langevin, C. D.; Clement, T. P.

2007-12-01

61

A chemical model of the buoyant and neutrally buoyant plume above the TAG vent field, 26 degrees N, Mid-Atlantic Ridge  

NASA Astrophysics Data System (ADS)

The kinetics of iron particle formation in the neutrally buoyant plume above the TAG vent field (26 degrees N, Mid-Atlantic Ridge) have been calculated from submersible-collected CTD data within the initial 150 m of plume rise. Results show that particles form by a two-stage process: about half the iron in the high temperature vent fluid is removed as sulfides within a few seconds of venting and the remainder is removed by Fe 2+ oxidation. The pseudo-first-order rate constant for the second process has been calculated ( k1 = 0.329min -1, similar to literature values for seawater) and gives a halflife time for Fe 2+ in solution of 2.1 minutes. The kinetics of iron particle formation have been used in a conceptual model of the chemistry of the TAG plume. The average dilution at which iron oxyhydroxide particles form, E¯ Fe, is ˜ 570 from which element/Fe ratios of particles at the top of the buoyant plume have been predicted. Oxyanion/Fe ratios can be chiefly accounted for by coprecipitation for Cr (71%), V (67%), As (45%) and P (42%) but Mo (0.1%) and U (0.02%) show anomalously low coprecipitation. Th/Fe and REE/Fe ratios are greater than can be accounted for by coprecipitation, demonstrating that scavenging occurs in the buoyant plume for these elements. 98% of the Th uptake and 15-75% of the REE uptake is by scavenging. Scavenging rate constants are 3.1 * 10 -6 (nmol/kg) -1 s -1 for Th and 1.4-33* 10 -8 (nmol/kg) -1 s -1 for the REE. A scavenging model has been fitted to trace metal data previously reported for neutrally buoyant hydrothermal plume particulate samples collected above the TAG vent field. The model is based on the assumption that there is a characteristic t1/2 for the dilution of the neutrally buoyant plume and this value has been calculated, by comparing 228Th and 230Th with 234Th isotope data, as fourty-one days (? p = 0.0170 day -1). Scavenging rate constants are 2* 10 -9 (nmol/kg) -1 s -1 for Th and 3.5-16*10 -11 (nmol/kg) -1 s -1 for the REE. This shows preferential removal of the intermediate REE from sea water, a pattern which has also been found in those TAG sediments formed from neutrally buoyant plume fallout. Chalcophile elements (Cu, Zn, Co, Pb, Sn) all appear to undergo release from plume particles at the same rate ( t1/2 ? 42days) suggesting alteration or removal of a common substrate. Model ages for particles above the TAG vent field are <50 days within 500 m of the vent field and 50-100 days at greater distances or below the height of the neutral plume. Quantitative removal of vent fluid derived REE, with the possible exception of Eu, during buoyant plume rise means that hydrothermal activity has no direct impact on the seawater chemistry of the REE. If coprecipitation and scavenging within the TAG hydrothermal plume are typical, such processes during plume rise (the buoyant plume) and dispersion (the neutrally buoyant plume) play a significant role in the removal of reactive trace metals and oxyanions from seawater, at rates of the same order as those of river input to the oceans.

Rudnicki, M. D.; Elderfield, H.

1993-07-01

62

Oil-entrapped sterculia gum-alginate buoyant systems of aceclofenac: development and in vitro evaluation.  

PubMed

The current investigation deals with the development and optimization of oil-entrapped sterculia gum-alginate buoyant beads containing aceclofenac by ionotropic emulsion-gelation technique using 3(2) factorial design. The effect of polymer to drug ratio and sodium alginate to sterculia gum ratio on the drug entrapment efficiency (%), and cumulative drug release after 7 h (%) was optimized. The optimized oil-entrapped sterculia gum-alginate buoyant beads containing aceclofenac (F-O) showed drug entrapment efficiency of 90.92±2.34%, cumulative drug release of 41.65±3.97% after 7 h in simulated gastric fluid (pH 1.2), and well buoyancy over 8 h in simulated gastric fluid (pH 1.2) with 5.20 min buoyant lag-time. The in vitro drug release from these buoyant beads followed Korsmeyer-Peppas model (R(2)=0.9866-0.9995) with anomalous (non-Fickian) diffusion drug release mechanism. These new sterculia gum-alginate buoyant beads containing aceclofenac were also characterized using SEM, FTIR, and P-XRD analysis. PMID:23334180

Guru, Pravat Ranjan; Nayak, Amit Kumar; Sahu, Rajendra Kumar

2012-12-20

63

Powering of cool filaments in cluster cores by buoyant bubbles - I. Qualitative model  

NASA Astrophysics Data System (ADS)

Cool-core clusters (e.g. Perseus or M87) often possess a network of bright gaseous filaments, observed in radio, infrared, optical and X-ray bands. We propose that these filaments are powered by the reconnection of the magnetic field in the wakes of buoyant bubbles. Active galactic nucleus (AGN)-inflated bubbles of relativistic plasma rise buoyantly in the cluster atmosphere, stretching and amplifying the field in the wake to values of ? = 8?Pgas/B2 ˜ 1. The field lines in the wake have opposite directions and are forced together as the bubble motion stretches the filament. This setup bears strong similarity to the coronal loops on the Sun or to the Earth's magnetotail. The reconnection process naturally explains both the required level of local dissipation rate in filaments and the overall luminosity of filaments. The original source of power for the filaments is the potential energy of buoyant bubbles, inflated by the central AGN.

Churazov, E.; Ruszkowski, M.; Schekochihin, A.

2013-09-01

64

Powering of cool filaments in cluster cores by buoyant bubbles - I. Qualitative model  

NASA Astrophysics Data System (ADS)

Cool-core clusters (e.g. Perseus or M87) often possess a network of bright gaseous filaments, observed in radio, infrared, optical and X-ray bands. We propose that these filaments are powered by the reconnection of the magnetic field in the wakes of buoyant bubbles. Active galactic nucleus (AGN)-inflated bubbles of relativistic plasma rise buoyantly in the cluster atmosphere, stretching and amplifying the field in the wake to values of ? = 8?Pgas/B2 ˜ 1. The field lines in the wake have opposite directions and are forced together as the bubble motion stretches the filament. This setup bears strong similarity to the coronal loops on the Sun or to the Earth's magnetotail. The reconnection process naturally explains both the required level of local dissipation rate in filaments and the overall luminosity of filaments. The original source of power for the filaments is the potential energy of buoyant bubbles, inflated by the central AGN.

Churazov, E.; Ruszkowski, M.; Schekochihin, A.

2013-11-01

65

The Buoyant Filter Bioreactor: a high-rate anaerobic reactor for complex wastewater—process dynamics with dairy effluent  

Microsoft Academic Search

A novel high-rate anaerobic reactor, called “Buoyant Filter Bioreactor” (BFBR), has been developed for treating lipid-rich complex wastewater. The BFBR is able to decouple the biomass and insoluble COD retention time from the hydraulic retention time by means of a granular filter bed made of buoyant polystyrene beads. Filter clogging is prevented by an automatic backwash driven by biogas release,

Ajit Haridas; S. Suresh; K. R. Chitra; V. B. Manilal

2005-01-01

66

Buoyant plumes from solute gradients generated by non-motile Escherichia coli  

NASA Astrophysics Data System (ADS)

The effect of hydrodynamic mixing in bacterial populations due to bacterial chemotaxis is a well-described phenomenon known as bioconvection. Here we report the observation of buoyant plumes that result in hydrodynamic mixing, but in contrast to bioconvection the plumes form in the absence of bacterial motility. We propose that the buoyant flow originates from solute gradients created by bacterial metabolism, similar to solute-induced buoyant flow around growing protein crystals. In our experiments, metabolically-active non-motile Escherichia coli were layered along the bottom of flat-bottomed containers. The E. coli consumed glucose in the medium creating a lighter fluid beneath a heavier fluid. The situation is an example of Rayleigh-Taylor instability, in which a lighter fluid pushes on a heavier one. We developed a numerical model to study the effect of E. coli nutrient consumption and by-product excretion on extracellular solute gradients. The model solutions showed reduced-density fluid along the bottom of the fluid domain leading to buoyant plumes, which were qualitatively similar to the experimental plumes. We also used scaling analyses to study the dependence of plume formation on container size and cell size, and to investigate the effect of reduced gravity, such as the microgravity conditions encountered during spaceflight.

Benoit, M. R.; Brown, R. B.; Todd, P.; Nelson, E. S.; Klaus, D. M.

2008-12-01

67

Effects of vent overpressure on buoyant eruption columns: Implications for plume stability  

Microsoft Academic Search

Volcanic plumes resulting from explosive volcanic eruptions present a variety of hazards depending on their behavior. Buoyant plumes heat and entrain enough of the surrounding air to rise high into the atmosphere, disrupting air traffic and causing regional ash fall. Alternatively, collapsed plumes produce dangerous fast-moving lateral flows of hot ash and gas. The transition between these behaviors and the

Darcy E. Ogden; Gary A. Glatzmaier; Kenneth H. Wohletz

2008-01-01

68

Interaction of a water mist with a buoyant methane diffusion flame  

Microsoft Academic Search

This work describes observations and measurements from the interaction of a fine water spray from a hollow cone nozzle, with purely buoyant diffusion flames from a natural gas ceramic-plate burner located directly underneath the nozzle. The burner plate was instrumented with thermocouples cemented on its upper and lower surfaces to assess the influence of the spray on the burner temperature.

George Gogos

1995-01-01

69

Sensitivity of buoyant plume heights to ambient atmospheric conditions: Implications for volcanic eruption columns  

Microsoft Academic Search

A theoretical model is developed to investigate the sensitivity of buoyant atmospheric plumes to a wide range of ambient atmospheric conditions, including the temperature gradient, the latitude of the source, and the season. The formulation highlights the compressibility of an ideal gas, internal consistency between the governing equations for the conservation of momentum and energy, and the explicit use of

Lori S. Glaze; Stephen M. Baloga

1996-01-01

70

The Effect of an Externally Attached Neutrally Buoyant Transmitter on Mortal Injury during Simulated Hydroturbine Passage  

SciTech Connect

On their seaward migration, juvenile salmonids commonly pass hydroelectric dams. Fish passing through hydroturbines experience a rapid decrease in pressure as they pass by the turbine blade and the severity of this decompression can be highly variable. This rapid decrease in pressure can result in injuries such as swim bladder rupture, exophthalmia, and emboli and hemorrhaging in the fins and tissues. However, recent research indicates that the presence of a telemetry tag (acoustic, radio, inductive) implanted inside the coelom of a juvenile salmon increases the likelihood that the fish will be injured or die during turbine passage. Thus, previous research conducted using telemetry tags implanted into the coelom of fish may have been inaccurate. Thus, a new technique is needed to provide unbiased estimates of survival through turbines. This research provides an evaluation of the effectiveness of a neutrally buoyant externally attached acoustic transmitter. Both nontagged fish and fish tagged with a neutrally buoyant external transmitter were exposed to a range of rapid decompressions simulating turbine passage. Juvenile Chinook salmon tagged with a neutrally buoyant externally attached acoustic transmitter did not receive a higher degree of barotrauma than their nontagged counterparts. We suggest that future research include field-based comparisons of survival and behavior among fish tagged with a neutrally buoyant external transmitter and those internally implanted with transmitters.

Brown, Richard S.; Pflugrath, Brett D.; Carlson, Thomas J.; Deng, Zhiqun

2012-02-03

71

Applying a Predict-Observe-Explain Sequence in Teaching of Buoyant Force  

ERIC Educational Resources Information Center

|An active learning sequence based on the predict-observe-explain teaching strategy is applied to a lesson on buoyant force. The results obtained clearly justify the use of this teaching method and suggest devising a series of activities to enable more effective removal of students' commonly held alternative conceptions regarding floating and…

Radovanovic, Jelena; Slisko, Josip

2013-01-01

72

Swaying motion in buoyant air plume above a horizontal line heat source  

Microsoft Academic Search

The swaying motion spectrum and frequency of a buoyant air laminar plume arising from a horizontal line heat source inside a 800 mm x 800 mm cross section 1000 mm high enclosure are determined experimentally. A smoke fullness method was developed for the flow visualization of the plume, which transits from laminar to turbulent flow with increase of distance from

K. Noto; R. Matsumoto

1986-01-01

73

Protoplast Water Content of Bacterial Spores Determined by Buoyant Density Sedimentation.  

National Technical Information Service (NTIS)

Protoplast wet densities (1.315 to 1.400 g/ml), determined by buoyant density sedimentation in Metrizamide gradients, were correlated inversely with the protoplast water contents (26.4 to 55.0 of water/100 g of wet protoplast) of nine diverse types of pur...

J. A. Lindsay T. C. Beaman P. Gerhardt

1985-01-01

74

Influence of roughness bottom on the dynamics of a buoyant cloud : application to a powder avalanche  

NASA Astrophysics Data System (ADS)

A powder avalanche is referred to as a turbulent flow of snow particles in air. In the past such avalanches have been modelled by buoyant cloud in a watertank: buoyant clouds flow along an inclined plane from a small immersed tank with a release gate (injection is of short duration). The powder avalanches are simulated by a heavy fluid (salt water + colorant or kaolin) which is dispersing in a lighter one. Such experiments allow studies for the influence of roughness bottoms on the dynamics of a buoyant clouds. The authors studied the flows of buoyant clouds on an uniform slope of 20° with different roughness: smooth PVC, abrasive paper, bottom covered with glued particles of PMMA or with glued glass beads of different sizes arranged in a compact way. The released volume varies between 2 to 4 liters and the density of salted water is 1.2. Two cameras are used to obtain the height together with the front velocity. Inside the study area the front velocity is approximately constant and the height of the clouds varies linearly with the distance from the released gate as usually observed in previous experiments. So for each roughness a front velocity and height growth can be defined. It was shown from the experiments that: As the bottom increases in roughness, the front speed increases and the height growth decreases. Nevertheless the height of glued elements does not seem to be the most appropriate parameter to characterize the roughness.

Brossard, D.; Naaim-Bouvet, F.; Naaim, M.; Caccamo, P.

2009-04-01

75

The Dynamics of Buoyant Magnetic Ropes and the Generation of Vorticity in their Periphery  

Microsoft Academic Search

When the Reynolds number is not small, the wake trailing a buoyant magnetic flux tube sheds vortex rolls therefore producing a Von Karman vortex street and an imbalance of vorticity in the tube which results in a transverse oscillation of the tube as a whole. The actual path followed by the magnetic structure is therefore directly affected by the amount

T. Emonet; F. Moreno-Insertis; M. P. Rast

2000-01-01

76

Buoyant density studies of several mecillinam-resistant and division mutants of Escherichia coli.  

PubMed Central

The buoyant density of wild-type Escherichia coli cells has previously been reported not to vary with growth rate and cell size or age. In the present report we confirm these findings, using Percoll gradients, and analyze the recently described lov mutant, which was selected for its resistance to mecillinam and has been suggested to be affected in the coordination between mass growth and envelope synthesis. The average buoyant density of lov mutant cells was significantly lower than that of wild-type cells. Similarly, the buoyant density of wild-type cells decreased in the presence of mecillinam. The density of the lov mutant, like that of the wild type, was invariant over a 2.8-fold range in growth rate. In this range, however, the average cell volume was also constant. Analysis of buoyant density as a function of cell volume in individual cultures revealed that smaller (newborn) lov mutant cells had higher density than larger (old) cells; however, the density of the small cells never approached that of the wild-type cells, whose density was independent of cell size (age). A pattern similar to that of lov mutant cells was observed in cells carrying the mecillinam-resistant mutations pbpA(Ts) and rodA(Ts) and the division mutation ftsI(Ts) at nonpermissive temperatures as well as in wild-type cells treated with mecillinam, but not in mecillinam-resistant crp or cya mutants. Images

Bylund, J E; Haines, M A; Walsh, K; Bouloc, P; D'Ari, R; Higgins, M L

1991-01-01

77

A theoretical and experimental study of buoyant turbulent flames with emphasis on soot and radiation  

Microsoft Academic Search

Accidental fires resulting from fuel spills and tank explosions commonly burn as pool fires. These fires contain large quantities of soot and radiates strongly. Computational methods have been developed to help fire safety designers reduce the hazards associated with such fires. ^ Motivated by this, theoretical and experimental studies of buoyant turbulent diffusion flames with emphasis on soot and radiation

Yibing Xin

2002-01-01

78

A buoyant plume adjacent to a headland—Observations of the Elwha River plume  

Microsoft Academic Search

Small rivers commonly discharge into coastal settings with topographic complexities – such as headlands and islands – but these settings are underrepresented in river plume studies compared to more simplified, straight coasts. The Elwha River provides a unique opportunity to study the effects of coastal topography on a buoyant plume, because it discharges into the Strait of Juan de Fuca

Jonathan A. Warrick; Andrew W. Stevens

2011-01-01

79

Poiseuille flow of a mixture of neutrally buoyant particles in a fluid  

Microsoft Academic Search

Constitutive equations are given for the stress, couple stress, and interphase momentum transfer in a mixture consisting of neutrally buoyant particles in a fluid. The interphase momentum transfer terms include objective expressions quantifying Stokes; drag, Faxen force, shear life, Magnus lift, and rotational drag. Coefficients of the drag and lift terms are deduced from macroscopic theory. The viscosity of the

Reinerrsman

1988-01-01

80

Applying a predict-observe-explain sequence in teaching of buoyant force  

NASA Astrophysics Data System (ADS)

An active learning sequence based on the predict-observe-explain teaching strategy is applied to a lesson on buoyant force. The results obtained clearly justify the use of this teaching method and suggest devising a series of activities to enable more effective removal of students’ commonly held alternative conceptions regarding floating and sinking.

Radovanovi?, Jelena; Sliško, Josip

2013-01-01

81

Study on The Surface Deformation in Buoyant-Thermcapillary Convection Using The Optical Bar Lines Method  

Microsoft Academic Search

In this paper surface deformation of the buoyant-thermocapillary convection in a rectangular cavity due to gravity and temperature gradient between the two sidewalls has been investigated Temperature difference is increased gradually and the flow in liquid layer will change from steady convection to unstable convection A new optical diagnostic system with image processor has been developed for the study of

Y. Yuan; D. Duan; K. Kang

2006-01-01

82

The Magnetostrophic Rise of A Buoyant Parcel In the Earth's Core  

Microsoft Academic Search

SUMMARY The dynamics of a buoyant parcel (or blob) of fluid released from the mushy zone on the inner core boundary (ICB) is considered. Estimates of the density defect and of the rise velocity are obtained from consideration of mass conservation and magnetostrophic force balance. When Lorentz and Coriolis forces are of comparable orders of magnitude, the disturbance remains localized

H. K. Moffatt; D. E. Loper

1994-01-01

83

Simultaneous velocity and passive scalar concentration measurements in low Reynolds number neutrally buoyant turbulent round jets  

Microsoft Academic Search

Velocity and scalar concentration characteristics of low Reynolds number (Re) neutrally buoyant turbulent round jets were studied using coupled particle image velocimetry and laser induced fluorescence.\\u000a Experiments were conducted on a jet with a fully developed pipe exit profile at Re = 1,500 and Re = 4,000. Measurements were made in the far field (60 x\\/D Re and the virtual origin is located far from the

G. A. Zarruk; E. A. Cowen

2008-01-01

84

Nuclear and Mitochondrial DNA from Wild-Type and Petite Yeast: Circularity, Length, and Buoyant Density  

Microsoft Academic Search

Purified mitochondrial and nuclear DNA from diploid isogenic wild-type and vegetative-petite baker's yeast were analyzed by electron microscopy and by analytical ultracentrifugation in CsCl gradients. The buoyant densities in CsCl of nuclear DNA were identical for the two strains (rho = 1.700), but there was a difference between mitochondrial DNA from the wild type (rho = 1.684) and the petite

Foster E. Billheimer; Charlotte J. Avers

1969-01-01

85

VISCOMETRIC FLOWS OF NEUTRALLY BUOYANT SUSPENSIONS IN SECOND-ORDER FLUIDS  

Microsoft Academic Search

The local volume averages of the equations of motion as well as the appropriate boundary conditions for neutrally buoyant suspensions of spheres in second-order fluids (Li and Slattery, 1989a) are employed to analyze both the cone-plate viscometer and the parallel-plate viscometer. The predicted results are compared with measurements of apparent viscosity and of the primary normal stress difference. Predictions of

ALFRED C. Li; JOHN C. SLATTERY; WILLIAM J. MILLIKEN; ROBERT L. POWELL

1989-01-01

86

Preparation of amoxicillin intragastric buoyant sustained-release tablets and the dissolution characteristics  

Microsoft Academic Search

An intragastric buoyant sustained-release tablet (IGB-T) containing 100 mg of amoxicillin (AMX) was prepared to eradicate gastric Helicobacter pylori. A tablet prepared by compressing the mixture of hydroxypropylcellulose-H (HPC-H), citric acid (17.2 mg), sodium hydrogen carbonate (22.8 mg) and AMX was employed as the basic system for preparing IGB-T. The weight and diameter of the tablets were designed to be

Tadakazu Tokumura; Yoshiharu Machida

2006-01-01

87

Magnetic stabilization of the buoyant convection in the liquid-encapsulated Czochralski process  

Microsoft Academic Search

This paper presents a linear stability analysis for the buoyant convection during the liquid-encapsulated Czochralski growth of compound semiconductor crystals with a steady, uniform, vertical magnetic field. Results are presented for two values of the Prandtl number, corresponding to indium-phosphide (InP) and gallium-arsenide (GaAs). Most of the results are for a melt depth equal to the crucible diameter, but some

J. S. Walker; D. Henry; H. BenHadid

2002-01-01

88

A numerical\\/experimental study of the dynamic structure of a buoyant jet diffusion flame  

Microsoft Academic Search

An overview of a joint numerical\\/experimental investigation of the dynamic structure of a low-speed buoyant jet diffusion flame is presented. The dynamic interactions between the flame surface and the surrounding fluid mechanical structures are studied by means of a direct numerical simulation closely coordinated with experiments. The numerical simulation employs the full compressible axisymmetric Navier-Stokes equations coupled with a flame

R. W. Davis; E. F. Moore; L.-D. Chen; W. M. Roquemore; V. Vilimpoc; L. P. Goss

1994-01-01

89

Nonlinear adjustment of a localized layer of buoyant, uniform potential vorticity fluid against a vertical wall  

Microsoft Academic Search

The nonlinear evolution of a localized layer of buoyant, uniform potential vorticity fluid with depth H, width w0 and length L released adjacent to a wall in a rotating system is studied using reduced-gravity shallow-water theory and numerical modeling. In the interior, far from the two ends of the layer, the initial adjustment gives, after ignoring inertia–gravity waves, a geostrophic

Karl R. Helfrich

2006-01-01

90

BUOYANT MAGNETIC LOOPS IN A GLOBAL DYNAMO SIMULATION OF A YOUNG SUN  

SciTech Connect

The current dynamo paradigm for the Sun and Sun-like stars places the generation site for strong toroidal magnetic structures deep in the solar interior. Sunspots and starspots on Sun-like stars are believed to arise when sections of these magnetic structures become buoyantly unstable and rise from the deep interior to the photosphere. Here, we present the first three-dimensional global magnetohydrodynamic (MHD) simulation in which turbulent convection, stratification, and rotation combine to yield a dynamo that self-consistently generates buoyant magnetic loops. We simulate stellar convection and dynamo action in a spherical shell with solar stratification, but rotating three times faster than the current solar rate. Strong wreaths of toroidal magnetic field are realized by dynamo action in the convection zone. By turning to a dynamic Smagorinsky model for subgrid-scale turbulence, we here attain considerably reduced diffusion in our simulation. This permits the regions of strongest magnetic field in these wreaths to rise toward the top of the convection zone via a combination of magnetic buoyancy instabilities and advection by convective giant cells. Such a global simulation yielding buoyant loops represents a significant step forward in combining numerical models of dynamo action and flux emergence.

Nelson, Nicholas J.; Toomre, Juri [JILA and Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309-0440 (United States); Brown, Benjamin P. [Department of Astronomy and Center for Magnetic Self-Organization (CSMO) in Laboratory and Astrophysical Plasmas, University of Wisconsin, Madison, WI 53706-1582 (United States); Brun, Allan Sacha [Laboratoire AIM Paris-Saclay, CEA/Irfu Universite Paris-Diderot CNRS/INSU, 91191 Gif-sur-Yvette (France); Miesch, Mark S. [High Altitude Observatory, NCAR, Boulder, CO 80307-3000 (United States)

2011-10-01

91

Experiments on the instability modes of buoyant diffusion flames and effects of ambient atmosphere on the instabilities  

Microsoft Academic Search

Large scale dynamic behavior of buoyant diffusion flames were studied experimentally. It was found that buoyant diffusion\\u000a flames originating from circular nozzles exhibit two different modes of flame instabilities. The first mode results in a sinuous\\u000a meandering of the diffusion flame, characteristic of flames originating from small diameter nozzles. This instability originates\\u000a at some distance downstream of the nozzle exit

B. M. Cetegen; Y. Dong

2000-01-01

92

Observations of currents and density structure across a buoyant plume front  

USGS Publications Warehouse

Observations of the Mobile Bay, Alabama, plume during a flood event in April 1991 reveal significant differences in the current field on either side of a front associated with the buoyant plume. During a strong southeasterly wind, turbid, low salinity water from Mobile Bay was pushed through an opening in the west side of the ebb-tidal delta and moved parallel to the coast. A stable front developed between the low salinity water of the buoyant plume (11???) and the high salinity coastal water (>23???) that was being forced landward by the prevailing winds. Despite the shallow water depth of 6 m, measurements of currents, temperature, and salinity show large shears and density gradients in both the vertical and the horizontal directions. At a station outside of the buoyant plume, currents at 0.5 m and 1.5 m below the surface were in the same direction as the wind. Inside the plume, however, currents at 0.5 m below the surface were parallel to the coast, 45??, off the direction of the wind and the magnitude was 45% larger than the magnitude of the surface currents outside the plume. Beneath the level of the plume, the currents were identical to the wind-driven currents in the ambient water south of the front. Our observations suggest that the wind-driven surface currents of the ambient water converged with the buoyant plume at the front and were subducted beneath the plume. The motion of the ambient coastal surface water was in the direction of the local wind stress, however, the motion of the plume had no northerly component of motion. The plume also did not show any flow toward the front, suggesting a balance between the northerly component of wind stress and the southerly component of buoyant spreading. In addition, the motion of the plume did not appear to affect the motion of the underlying ambient water, suggesting a lack of mixing between the two waters. ?? 1993 Estuarine Research Federation.

Gelfenbaum, G.; Stumpf, R. P.

1993-01-01

93

Small dense LDL is more susceptible to glycation than more buoyant LDL in Type 2 diabetes.  

PubMed

Glycation of apoB (apolipoprotein B) of LDL (low-density lipoprotein) increases its atherogenicity. Concentrations of both serum glyc-apoB (glycated apoB) and SD-LDL (small dense LDL) (syn LDL3; D=1.044-1.063 g/ml) are increased in diabetes and are closely correlated. We studied whether SD-LDL is more susceptible to glycation in vitro than more buoyant LDL in statin- and non-statin-treated Type 2 diabetes mellitus. Serum SD-LDL apoB and glyc-apoB on statins was 20±2 (means±S.D.) and 3.6±0.41 compared with 47±3 and 5.89±0.68 mg/dl in those not receiving statins (P<0.001 and <0.01, respectively). There was a dose-dependent increase in glycation on incubation of LDL subfractions with glucose, which was accompanied by an increase in LPO (lipid peroxide) and electrophoretic mobility and a decrease in free amino groups. SD-LDL was more susceptible to these changes than more buoyant LDL. Both SD-LDL and more buoyant LDL from statin-treated patients were less susceptible to glycation. There were fewer free amino groups on LDL subfractions from statin-treated patients, which may contribute to this resistance. In conclusion, greater susceptibility of SD-LDL to glycation is likely to contribute to the raised levels of circulating glyc-apoB in diabetes. Statins are associated with lower levels of both SD-LDL and glyc-apoB. PMID:22985435

Younis, Nahla N; Soran, Handrean; Pemberton, Philip; Charlton-Menys, Valentine; Elseweidy, Mohamed M; Durrington, Paul N

2013-03-01

94

Effects of vent overpressure on buoyant eruption columns: Implications for plume stability  

NASA Astrophysics Data System (ADS)

Volcanic plumes resulting from explosive volcanic eruptions present a variety of hazards depending on their behavior. Buoyant plumes heat and entrain enough of the surrounding air to rise high into the atmosphere, disrupting air traffic and causing regional ash fall. Alternatively, collapsed plumes produce dangerous fast-moving lateral flows of hot ash and gas. The transition between these behaviors and the nature of each hazard is dependent on the fluid dynamics of the volcanic plume, which is largely determined by the conditions at the vent. Most treatments of volcanic plumes for hazard assessment assume that the eruptive fluid exits the vent at pressures equal to atmospheric pressure or that pressure equalizes quickly with little effect on the flow. Here we show that vent pressures greater than atmospheric lead to rapid expansion of the plume and the development of standing shock waves that change the behavior of the entire eruption column. We simulate two volcanic plumes with the same heat flow (J s- 1) at the vent; one exits the vent at atmospheric pressure (pressure-balanced) and the other at four times atmospheric pressure (overpressured). The two simulated plumes have the same radius after the initial rapid decompression of the overpressured case. These plumes show drastically different behavior due to the presence of standing shock waves in the overpressured case despite having the same heat flow at the vent and the same area available for entrainment of ambient air. Both simulated plumes exhibit buoyant rise but the overpressured plume collapses with a regular periodicity. These simulations suggest that the dynamics of a steady-state overpressured vent may result in plumes that oscillate between buoyant rise and collapse, providing a mechanism for the deposition of intraplinian pyroclastic flows.

Ogden, Darcy E.; Glatzmaier, Gary A.; Wohletz, Kenneth H.

2008-04-01

95

Large-Eddy Simulation of a Turbulent Buoyant Flame Interacting with Droplets  

NASA Astrophysics Data System (ADS)

A dynamic large-eddy simulation methodology is applied to a simplified water-spray fire suppression system to investigate droplet effects on a buoyant gas flame. A hybrid Eulerian-Lagrangian approach is employed for the gas-liquid system. Dynamic subgrid models are included to capture the local and unsteady interactions between the two phases. The effectiveness of changing spray angles on combustion suppression has been investigated. The drag effects of droplets cause significant changes to the flow and flame structures. Dense droplets, in particular, can cut through the reaction zones, causing flame extinction. The high temperature regions associated with reaction zones are suppressed by the spray droplets in all cases.

Xia, J.; Luo, K. H.; Kumar, S.

96

Information Request for Dendreon's Pli - Provenge  

Center for Biologics Evaluation and Research (CBER)

... Large, legible diagrams illustrating AHUs, room classifications, pressure differentials and flows (product, material, equipment, personnel and waste ... More results from www.fda.gov/biologicsbloodvaccines/cellulargenetherapyproducts/approvedproducts

97

Telecon with Dendreon - Provenge, November 12, 2007  

Center for Biologics Evaluation and Research (CBER)

... She thanked me for the information provided and said they would be sure to have Mike Poor from Scheduling and someone from QC to be present ... More results from www.fda.gov/biologicsbloodvaccines/cellulargenetherapyproducts/approvedproducts

98

Dendreon PLI - Preliminary Report - Provenge, February 25 ...  

Center for Biologics Evaluation and Research (CBER)

... ReportFrom: Finn, Thomas Sent: Thursday, February 25, 2010 10:41 AM To: 'Smith, Liz' Cc: Oh, Steven; Tull, Lori; Wang, Gang; Melhem, Randa ... More results from www.fda.gov/biologicsbloodvaccines/cellulargenetherapyproducts/approvedproducts

99

Correspondence Between Dendreon and CBER - Provenge ...  

Center for Biologics Evaluation and Research (CBER)

... Changes_Final-hk.xls; KM_DP01_20070205 (2).doc; Subject 9125-017 Query.pdf. ... This email message including any attachments is for the sole ... More results from www.fda.gov/biologicsbloodvaccines/cellulargenetherapyproducts/approvedproducts

100

FW: Dendreon Provenge CDER BLA Labeling Consult ...  

Center for Biologics Evaluation and Research (CBER)

... statement reads: “PROVENGE® is indicated for the treatment of men with metastatic castrate resistant (hormone refractory) prostate cancer.” The ... More results from www.fda.gov/biologicsbloodvaccines/cellulargenetherapyproducts/approvedproducts

101

RE: Discussion of Dendreon Pharmacovigilance Plan (Internal ...  

Center for Biologics Evaluation and Research (CBER)

... preclude licensure or require a REMS (generally meaning it is not a strong signal), then we ask "Does it meet one of the criteria in the FDA AA for a ... More results from www.fda.gov/biologicsbloodvaccines/cellulargenetherapyproducts/approvedproducts

102

A simple technique for measuring buoyant weight increment of entire, transplanted coral colonies in the field  

PubMed Central

Estimating the impacts of global and local threats on coral reefs requires monitoring reef health and measuring coral growth and calcification rates at different time scales. This has traditionally been mostly performed in short-term experimental studies in which coral fragments were grown in the laboratory or in the field but measured ex situ. Practical techniques in which growth and measurements are performed over the long term in situ are rare. Apart from photographic approaches, weight increment measurements have also been applied. Past buoyant weight measurements under water involved a complicated and little-used apparatus. We introduce a new method that combines previous field and laboratory techniques to measure the buoyant weight of entire, transplanted corals under water. This method uses an electronic balance fitted into an acrylic glass underwater housing and placed atop of an acrylic glass cube. Within this cube, corals transplanted onto artificial bases can be attached to the balance and weighed at predetermined intervals while they continue growth in the field. We also provide a set of simple equations for the volume and weight determinations required to calculate net growth rates. The new technique is highly accurate: low error of weight determinations due to variation of coral density (< 0.08%) and low standard error (< 0.01%) for repeated measurements of the same corals. We outline a transplantation technique for properly preparing corals for such long-term in situ experiments and measurements.

Herler, Jurgen; Dirnwober, Markus

2011-01-01

103

Detection of a buoyant coastal wastewater discharge using airborne hyperspectral and infrared imagery  

NASA Astrophysics Data System (ADS)

Municipal wastewater discharged into the ocean through a submerged pipe, or outfall, can rise buoyantly to the sea surface, resulting in a near-field mixing zone and, in the presence of an ambient ocean current, an extended surface plume. In this paper, data from a CASI (Compact Airborne Spectrographic Imager) and an airborne infrared (IR) camera are shown to detect a municipal wastewater discharge off the southeast coast of Florida, U.S.A., through its elevated levels of chromophoric dissolved organic matter plus detrital material (CDOM) and cooler sea surface temperatures. CDOM levels within a ~15-m-diameter surface 'boil' are found to be about twice those in the ambient shelf water, and surface temperatures near the boil are lower by ~0.4°C, comparable to the vertical temperature difference across the ambient water column. The CASI and IR imagery show a nearly identically shaped buoyant plume, consistent with a fully surfacing discharge, but the IR data more accurately delineate the area of most rapid dilution as compared with previous in-situ measurements. The imagery also allows identification of ambient oceanographic processes that affect dispersion and transport in the far field. This includes an alongshore front, which limits offshore dispersion of the discharge, and shoreward-propagating nonlinear internal waves, which may be responsible for an enhanced onshore transport of the discharge.

Marmorino, George O.; Smith, Geoffrey B.; Miller, W. D.; Bowles, Jeffrey H.

2010-01-01

104

Impact of variable inflow on the dynamics of a coastal buoyant plume  

NASA Astrophysics Data System (ADS)

The impact of buoyant discharge variations on the dynamics of coastal buoyancy-driven currents is studied using a primitive equation numerical model (SPEM5). First, variable discharge is introduced as harmonic fluctuations of the inflow velocity at the tidal (period 12 hours) and subinertial (period 10 days) frequencies. Tidal fluctuations produce only minor effects on the buoyant plume compared to the case of constant inflow, while subinertial fluctuations substantially modify the anticyclonic bulge. A partially detached anticyclonic plume forms when discharge subsides after reaching its peak value. Such a plume has maximum offshore extension some distance downstream of the mouth with the lightest water separated from the coast. A secondary bulge forms during the low runoff interval. When high discharge resumes, this secondary bulge is shifted offshore and enhanced for some time. An individual high-discharge event is next considered, where both the net transport of the inflow and the absolute value of its density anomaly increase and then return to their initial (background) values over 5 and 10 day time intervals. This event also generates a partially detached plume (especially with the 10 day duration). In this case, the lightest water occupies the downstream part of the bulge and is separated not only from the coast but also from the mouth. The effect of variable discharge is more dramatic with a uniform downstream current of 0.1 m s-1. Under such conditions, constant buoyant discharge does not form a well-pronounced anticyclonic bulge. In contrast, variable discharge produces an almost circular anticyclone during the high-runoff interval. As runoff decreases, this anticyclone separates from the source and either continues to propagate downstream as an individual eddy or is modified by the next cycle of increasing discharge. Observational evidence for both the partially detached bulge near the mouth and the anticyclone propagating downstream from its source is presented in this study. One feature was observed at the mouth of the Columbia River estuary; the second feature was observed off the southern New Jersey coast ˜150 km south of its source, the Hudson estuary.

Yankovsky, Alexander E.; Hickey, Barbara M.; Münchow, Andreas K.

2001-09-01

105

Laminar Smoke Point Based Subgrid Soot Radiation Modeling Applied to LES of Buoyant Turbulent Diffusion Flames  

NASA Astrophysics Data System (ADS)

Large eddy simulations (LES) of gaseous buoyant turbulent flames have been conducted with the application of a flamelet based soot-radiation model. The subgrid model applies a turbulent eddy description of soot formation, oxidation and radiation and is based on the laminar smoke point concept. Two parameters, a local turbulent strain rate and prior enthalpy loss/gain fraction influence the soot formation and radiation. Radiation heat transfer is simulated by solving the finite volume discretized form of the radiative transfer equation (RTE) with the subgrid soot-radiation model implemented. The radiant heating of surfaces in close proximity of the flames is computed and predicted heat fluxes and surface temperatures are compared against experimental data. Fire growth in a rack storage arrangement is simulated with the application of a pyrolysis model. Computed heat release rate (HRR) is compared against experimental data.

Chatterjee, Prateep; de Ris, John L.; Wang, Yi; Krishnamoorthy, Niveditha; Dorofeev, Sergey B.

2012-06-01

106

Inertial migration of neutrally buoyant particles in a square duct: An investigation of multiple equilibrium positions  

NASA Astrophysics Data System (ADS)

Inertial migration of neutrally buoyant particles in a square duct has been investigated by numerical simulation in the range of Reynolds numbers from 100 to 1000. Particles migrate to one of a small number of equilibrium positions in the cross-sectional plane, located near a corner or at the center of an edge. In dilute suspensions, trains of particles are formed along the axis of the flow, near the planar equilibrium positions of single particles. At high Reynolds numbers (Re>=750), we observe particles in an inner region near the center of the duct. We present numerical evidence that closely spaced pairs of particles can migrate to the center at high Reynolds number.

Chun, B.; Ladd, A. J. C.

2006-03-01

107

Numerical simulation of time-dependent buoyant flows in an enclosed vertical channel  

NASA Astrophysics Data System (ADS)

A time-accurate Finite Volume method is used to investigate the two-dimensional buoyant flow in a closed cabinet containing two vertical heating plates. These are parallel, and form a channel at the centre of the cabinet enclosure. The cases of isothermal plates, and of uniform heat generation within them, are both considered for two values, 1×105 and 1×107, of the leading non-dimensional parameter, the Grashof number. Air (Pr = 0.71) is considered as the working fluid. Transient and long term thermal and flow behaviours are investigated. Steady-state solutions are asymptotically found at the lower Gr-value. However, time-dependent long-term solutions are predicted at Gr = 1×107.

Barozzi, G. S.; Corticelli, M. A.; Nobile, E.

108

Buoyant replenishment in silicic magma reservoirs: Experimental approach and implications for magma dynamics, crystal mush remobilization, and eruption  

Microsoft Academic Search

We present new experiments on replenishment of rhyolite magma chambers by rhyolite magma using corn syrup-water solutions. We emphasize small density contrasts and show that buoyancy is the key controlling factor for whether injections will rise to the top (if buoyant) or pond at the base (if denser). During emplacement, we observe little or no mixing of the injected liquid

Guillaume Girard; John Stix

2009-01-01

109

Optical measurements of the effects on a boundary layer of puffing in a large scale buoyant plume  

Microsoft Academic Search

An experimental study has been performed on a buoyant helium plume with a 1 meter base diameter. A cone was immersed in the plume to determine the effect of plume puffing on the boundary layer along the cone. The plume with an immersed cone was also compared to an unobstructed plume. Two regions of two-dimensional velocity fields were measured using

Andrew L. Gerhart

2004-01-01

110

THE LOCAL VOLUME-AVERAGED EQUATIONS OF MOTION FOR A SUSPENSION OF NON-NEUTRALLY BUOYANT SPHERES  

Microsoft Academic Search

The local volume averages of the equations of motion as well as the appropriate boundary conditions are developed for a flowing suspension of non-neutrally buoyant, uniform spheres in an incompressible Newtonian fluid under conditions such that inertial effects can be neglected. These equations do not represent an asymptotic theory with respect to the volume fraction of solids. Higher order terms

TSUNG-SHANN JIANG; MICHAEL H. KIM; VICTOR J. KREMESEC; JOHN C. SLATTERY

1987-01-01

111

NON-UNIFORM PARTICLE DISTRIBUTIONS DURING TUBE FLOWS OF NEUTRALLY BUOYANT SUSPENSIONS IN SECOND-ORDER FLUIDS  

Microsoft Academic Search

Flow through an inclined tube of a suspension of uniform, neutrally buoyant spheres in a second-order fluid has been analyzed using the theory of (Li and Slattery, 1989) The result predicts that the spheres will migrate toward the center of the tube, forming a core with a maximum packing density. The velocity and concentration distributions agree qualitatively with previous observations.

ALFRED C. LI; JOHN C. SLATTERY

1991-01-01

112

Liquid-metal buoyant convection in a vertical cylinder with a strong vertical magnetic field and with a nonaxisymmetric temperature  

Microsoft Academic Search

In this paper the buoyant convection of a liquid metal in a circular cylinder with a vertical axis and with electrically insulating walls is treated. There is an externally applied, uniform, vertical magnetic field. A nonaxisymmetric heat flux at the vertical wall of the cylinder produces a nonaxisymmetric temperature, which drives a nonaxisymmetric liquid motion. The magnetic field is sufficiently

Nancy Ma; John S. Walker

1995-01-01

113

Laboratory and numerical model studies of a negatively-buoyant jet discharged horizontally into a homogeneous rotating fluid  

Microsoft Academic Search

The results of laboratory experiments and numerical model simulations are described in which the motion of a round, negatively-buoyant, turbulent jet discharged horizontally above a slope into a rotating homogeneous fluid has been investigated. For the laboratory study, flow visualisation data are presented to show the complex three-dimensional flow fields generated by the discharge. Analysis of the experimental data indicates

Peter A. Davies; Rolf H. Käse; Iftikhar Ahmed

2001-01-01

114

On the dynamics of volcanic columns: A comparison of field data with a new model of negatively buoyant jets  

Microsoft Academic Search

Explosive volcanic eruptions propel high-velocity turbulent jets into the atmosphere and are one of the most powerful and dangerous turbulent flows on Earth. Such eruptions are particularly difficult to predict due to their unusual dynamics that allow the jet to form a high buoyant Plinian plume or dense pyroclastic flows when the column collapses. A major goal of physical volcanology

G. Carazzo; E. Kaminski; S. Tait

2008-01-01

115

Flow-Field Characteristics of High-Temperature Annular Buoyant Jets and Their Development Laws Influenced by Ventilation System  

PubMed Central

The flow-field characteristics of high-temperature annular buoyant jets as well as the development laws influenced by ventilation system were studied using numerical methods to eliminate the pollutants effectively in this paper. The development laws of high-temperature annular buoyant jets were analyzed and compared with previous studies, including radial velocity distribution, axial velocity and temperature decay, reattachment position, cross-section diameter, volumetric flow rate, and velocity field characteristics with different pressures at the exhaust hood inlet. The results showed that when the ratio of outer diameter to inner diameter of the annulus was smaller than 5/2, the flow-field characteristics had significant difference compared to circular buoyant jets with the same outer diameter. For similar diameter ratios, reattachment in this paper occurred further downstream in contrast to previous study. Besides, the development laws of volumetric flow rate and cross-section diameter were given with different initial parameters. In addition, through analyzing air distribution characteristics under the coupling effect of high-temperature annular buoyant jets and ventilation system, it could be found that the position where maximum axial velocity occurred was changing gradually when the pressure at the exhaust hood inlet changed from 0?Pa to ?5?Pa.

Liu, Jiaping; Wang, Hai; Liu, Qiuhan

2013-01-01

116

Aligned buoyant highs, across-trench deformation, clustered volcanoes, and deep earthquakes are not aligned with plate-tectonic theory  

Microsoft Academic Search

Bathymetry shows the regional interaction of aseismic, buoyant highs in northern Pacific subduction zones. Seamounts, ridges, and fractures on the seaward side of the trench are associated with events that do not support the accepted plate-tectonics paradigm, including an altered slab dip angle (Benioff zone) and the clustered volcanoes and earthquakes within the convergent margin. Most of the examples in

N. Christian Smoot

1997-01-01

117

Laboratory Experiments Simulating the Effects of Variable Discharge on Buoyant Coastal Plumes  

NASA Astrophysics Data System (ADS)

River plumes are of great importance to coastal ecosystems because they carry nutrients and contaminants from upstream, which can become trapped near the coast in a growing anticyclonic eddy, or bulge. The degree to which river water is trapped in this coastal eddy is associated strongly with the river discharge. In meso- to macro-tidal systems, ebb and flood tidal phases may result in increases and decreases, respectively, of the effective river discharge of a similar magnitude to the discharge itself. Thus, accumulation of fluid in the bulge may depend on the relative magnitude of the tidal forcing or other modulations of the river discharge. Field observations suggest that under some conditions, discharge variation can cause the anticyclonic eddy to become detached and swept downstream, rather than continuing to grow near the mouth. We carry out laboratory experiments to simulate the effects of periodically varying discharge on buoyant coastal plumes over a range of oscillation periods by injecting a sinusoidally pulsed freshwater inflow into a 2 meter diameter rotating tank of salt water. The depth of the plume in the vicinity of the river mouth is determined from an overhead camera using an optical thickness technique. Using this technique, the temporal evolution of the plume volume can be determined directly. Preliminary results confirm that approximately 65% of the discharge remains in the bulge region in the absence of tidal forcing. In the presence of tidal forcing plume growth appears to be slowed, thereby increasing the transport of buoyant water downstream in the coastal current. Finally, the plume is almost entirely arrested when the pulsing frequency is half of the rotation frequency.

Avener, M. E.; Horner-Devine, A. R.; Rhines, P. B.

2008-12-01

118

Isolation and characterization of high-buoyant-density proteoglycans from bovine femoral-head cartilage.  

PubMed Central

Proteoglycans were extracted from bovine (15-18 months old) femoral-head cartilage. The heterogeneity of the A1D1 proteoglycan fraction was examined by gel chromatography, sedimentation velocity, sucrose rate-zonal centrifugation and CS2SO4 isopycnic centrifugation. In all cases polydisperse but unimodal distributions were obtained. Chemical analysis of the preparation yielded a galactosamine/glucosamine molar ratio of 7:1, and 13C n.m.r. spectroscopy showed that the chondroitin sulphate comprised equal proportions of the 4- and 6-sulphate isomers. Gel chromatography of a papain and Pronase digest of the proteoglycan indicated that the chondroitin sulphate chains had a Mn of approx. 10500. The mean buoyant density of the proteoglycan in pure CS2SO4 was 1.46 g/ml. Physical characterization of the proteoglycan preparation in 4M-guanidine hydrochloride, pH 7.4, by using conventional light-scattering gave a radius of gyration of 42 nm and a Mw of 0.96 X 10(6). Quasi-elastic light-scattering in the same solvent yielded a translational diffusion coefficient, D020, of 5.41 X 10(-8) cm2 X S-1, and ultracentrifugation gave a sedimentation coefficient, S020, of 12.0S. Thus from sedimentation-diffusion studies a Mw of 1.36 X 10(6) was calculated. The possible origins for the differences in the two molecular-weight estimates are discussed. It is concluded that the high-buoyant-density proteoglycans from bovine articular cartilage are significantly smaller than those from bovine nasal septum, and that this is largely due to the smaller size of their chondroitin sulphate chains.

Lyon, M; Greenwood, J; Sheehan, J K; Nieduszynski, I A

1983-01-01

119

Stability of buoyant convection in a layer submitted to acoustic streaming.  

PubMed

The linear stability of the flows induced in a fluid layer by buoyant convection (due to an applied horizontal temperature gradient) and by acoustic streaming (due to an applied horizontal ultrasound beam) is studied. The vertical profiles of the basic flows are determined analytically, and the eigenvalue problem resulting from the temporal stability analysis is solved by a spectral Tau Chebyshev method. Pure acoustic streaming flows are found to be sensitive to a shear instability developing in the plane of the flow (two-dimensional instability), and the thresholds for this oscillatory instability depend on the normalized width Hb of the ultrasound beam with a minimum for Hb=0.32 . Acoustic streaming also affects the stability of the buoyant convection. For a centered beam, effects of stabilization are obtained at small Prandtl number Pr for large beam widths Hb (two-dimensional shear instability) and for moderate Pr (three-dimensional oscillatory instability), but destabilization is also effective at small Pr for small beam widths Hb and at large Pr with a spectacular decrease of the thresholds of the three-dimensional steady instability. An adequate decentring of the ultrasound beam can enhance the stabilization. Insight into the stabilizing and destabilizing mechanisms is gained from the analysis of the fluctuating energy budget associated with the disturbances at threshold. The modifications affecting the two-dimensional shear instability thresholds are strongly connected to modifications of the velocity fluctuations when acoustic streaming is applied. Concerning the three-dimensional steady instability, the spectacular decrease of the thresholds is explained by the extension of the zone with inverse stratification in the lower half of the layer. PMID:20866324

Dridi, W; Henry, D; Ben Hadid, H

2010-05-11

120

Stability of buoyant convection in a layer submitted to acoustic streaming  

NASA Astrophysics Data System (ADS)

The linear stability of the flows induced in a fluid layer by buoyant convection (due to an applied horizontal temperature gradient) and by acoustic streaming (due to an applied horizontal ultrasound beam) is studied. The vertical profiles of the basic flows are determined analytically, and the eigenvalue problem resulting from the temporal stability analysis is solved by a spectral Tau Chebyshev method. Pure acoustic streaming flows are found to be sensitive to a shear instability developing in the plane of the flow (two-dimensional instability), and the thresholds for this oscillatory instability depend on the normalized width Hb of the ultrasound beam with a minimum for Hb=0.32 . Acoustic streaming also affects the stability of the buoyant convection. For a centered beam, effects of stabilization are obtained at small Prandtl number Pr for large beam widths Hb (two-dimensional shear instability) and for moderate Pr (three-dimensional oscillatory instability), but destabilization is also effective at small Pr for small beam widths Hb and at large Pr with a spectacular decrease of the thresholds of the three-dimensional steady instability. An adequate decentring of the ultrasound beam can enhance the stabilization. Insight into the stabilizing and destabilizing mechanisms is gained from the analysis of the fluctuating energy budget associated with the disturbances at threshold. The modifications affecting the two-dimensional shear instability thresholds are strongly connected to modifications of the velocity fluctuations when acoustic streaming is applied. Concerning the three-dimensional steady instability, the spectacular decrease of the thresholds is explained by the extension of the zone with inverse stratification in the lower half of the layer.

Dridi, W.; Henry, D.; Ben Hadid, H.

2010-05-01

121

Small-scale hydromagnetic flow in the Earth's core: Rise of a vertical buoyant plume  

NASA Astrophysics Data System (ADS)

The steady and transient flow induced by a vertical cylinder of buoyant electrically conducting fluid immersed in an infinite extent of slightly denser fluid in the presence of a horizontal magnetic field is investigated, with the aim of elucidating the small-scale flow within the Earth's core. The evolution from a state of rest may be divided into three regimes. For short times [t < O(L2) where L is the horizontal scale of the plume] Alfvén waves propagate a distance VAt along the magnetic field lines, accelerating the fluid to a speed of order ()gL/?VA where VA = B/(??) 1/2 is the Alfvén speed and ?? is the density deficit of the buoyant plume. For intermediate times [O(L2?s)t O(L2/v)] lateral viscous diffusion also becomes important and a quasi-steady state is reached having rise speed of order (??)gL/B(?sv)½ and lateral extent of order L2B(s/?v)½. For values of parameters thought to be relevant to the core, the short-time solution lasts roughly an hour and the intermediate-time solution lasts several decades. The long-time solution may not be relevant to the core as the fluid can rise to the top during the intermediate-time regime. The rise speeds associated with this plume flow may exceed those estimated from secular variation, but this result is sensitive to the size of the density deficit, which is poorly known, and to the particular orientation of the plume that has been chosen.

Loper, David E.; Moffatt, H. Keith

122

Melting due to Buoyant Migration of Water in the Hot Mantle Wedge Above a Subducting Plate  

NASA Astrophysics Data System (ADS)

Water-bearing magma generated at convergent plate boundaries is thought to be due to the release of water carried to depth by the subducting crust and mantle. The objective of our study is to create models of the buoyant upward migration of water-rich fluids from the slab, through the hot mantle wedge, and consequent mantle melting. Fluid in the models is assumed to migrate buoyantly along mineral grain edges with a prescribed melt fraction-grain size-permeability relationship (e.g. Wark et al., 2003). Pressure gradients in the solid mantle flow should be important to melt migration only if the mantle viscosity exceeds about 1018 Pa-s. The model results thus far neglect the effect of solid deformation on melt permeability, including the possible effects of the dependence of grain size on stress and the anisotropic permeability created by solid deformation (e.g. Kohlstedt and Zimmerman, 1996). The volume of melt generated by the interaction of water with the mantle is parameterized using results from MELTS (Ghiorso and Sack, 1995). The volume of water released from the slab between depths of 80 to 150 km is derived from the estimates of Schmidt and Poli (1998). The models consider a range of slab velocities and grain sizes using solid flow and temperature distributions from an earlier model with temperature-dependent viscosity (Kelemen et al., 2003). Melt distribution in the wedge is strongly dependent on both grain size and slab velocity. For a grain size of 2 mm at slab velocities of 2-6 cm/yr, fluid rises from the slab to generate melt. At higher plate velocities or smaller grain sizes, water released from the slab is carried downward into the deeper mantle, in which case melting is not triggered. As a consequence, melt flux at the top of the mantle wedge also varies significantly with convergence rate. At slow to intermediate rates, calculated melt fluxes are comparable to values observed in island arcs. Thus, in the absence of other effects, significant differences in volcanic flux between fast and slow convergence rates would be expected. In appropriate nondimensional form, the ratio of slab velocity to the square of the grain size controls the distribution of fluids in the wedge. In nature, the absence of such a strong convergence rate dependence on magmatic flux might indicate that grain size in the mantle wedge varies with plate velocity. Thus, future work should consider the effect of variable grain size on melt permeability. Accounting for hydrous mineral stability limits may also introduce a convergence rate and plate age dependence to predicted volcanic flux.

Rilling, J. L.; Cagnioncle, A. M.; Elkins-Tanton, L. T.; Parmentier, E. M.

2003-12-01

123

Evolution of localized blobs of swirling or buoyant fluid with and without an ambient magnetic field  

SciTech Connect

We investigate the evolution of localized blobs of swirling or buoyant fluid in an infinite, inviscid, electrically conducting fluid. We consider the three cases of a strong imposed magnetic field, a weak imposed magnetic field, and no magnetic field. For a swirling blob in the absence of a magnetic field, we find, in line with others, that the blob bursts radially outward under the action of the centrifugal force, forming a thin annular vortex sheet. A simple model of this process predicts that the vortex sheet thins exponentially fast and that it moves radially outward with constant velocity. These predictions are verified by high-resolution numerical simulations. When an intense magnetic field is applied, this phenomenon is suppressed, with the energy and angular momentum of the blob now diffusing axially along the magnetic field lines, converting the blob into a columnar structure. For modest or weak magnetic fields, there are elements of both types of behavior, with the radial bursting dominating over axial diffusion for weak fields. However, even when the magnetic field is very weak, the flow structure is quite distinct to that of the nonmagnetic case. In particular, a small but finite magnetic field places a lower bound on the thickness of the annular vortex sheet and produces an annulus of counter-rotating fluid that surrounds the vortex core. The behavior of the buoyant blob is similar. In the absence of a magnetic field, it rapidly develops the mushroomlike shape of a thermal, with a thin vortex sheet at the top and sides of the mushroom. Again, a simple model of this process predicts that the vortex sheet at the top of the thermal thins exponentially fast and rises with constant velocity. These predictions are consistent with earlier numerical simulations. Curiously, however, it is shown that the net vertical momentum associated with the blob increases linearly in time, despite the fact that the vertical velocity at the front of the thermal is constant. As with the swirling blob, an imposed magnetic field inhibits the formation of a vortex sheet. A strong magnetic field completely suppresses the phenomenon, replacing it with an axial diffusion of momentum, while a weak magnetic field allows the sheet to form, but places a lower bound on its thickness. The magnetic field does not, however, change the net vertical momentum of the blob, which always increases linearly with time.

Davidson, P. A. [Department of Engineering, University of Cambridge, Cambridge, CB2 1PZ (United Kingdom); Sreenivasan, Binod [School of Earth and Environment, University of Leeds, Leeds, LS2 9JT (United Kingdom); Aspden, A. J. [Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, CB3 0WA (United Kingdom)

2007-02-15

124

Evolution of localized blobs of swirling or buoyant fluid with and without an ambient magnetic field  

NASA Astrophysics Data System (ADS)

We investigate the evolution of localized blobs of swirling or buoyant fluid in an infinite, inviscid, electrically conducting fluid. We consider the three cases of a strong imposed magnetic field, a weak imposed magnetic field, and no magnetic field. For a swirling blob in the absence of a magnetic field, we find, in line with others, that the blob bursts radially outward under the action of the centrifugal force, forming a thin annular vortex sheet. A simple model of this process predicts that the vortex sheet thins exponentially fast and that it moves radially outward with constant velocity. These predictions are verified by high-resolution numerical simulations. When an intense magnetic field is applied, this phenomenon is suppressed, with the energy and angular momentum of the blob now diffusing axially along the magnetic field lines, converting the blob into a columnar structure. For modest or weak magnetic fields, there are elements of both types of behavior, with the radial bursting dominating over axial diffusion for weak fields. However, even when the magnetic field is very weak, the flow structure is quite distinct to that of the nonmagnetic case. In particular, a small but finite magnetic field places a lower bound on the thickness of the annular vortex sheet and produces an annulus of counter-rotating fluid that surrounds the vortex core. The behavior of the buoyant blob is similar. In the absence of a magnetic field, it rapidly develops the mushroomlike shape of a thermal, with a thin vortex sheet at the top and sides of the mushroom. Again, a simple model of this process predicts that the vortex sheet at the top of the thermal thins exponentially fast and rises with constant velocity. These predictions are consistent with earlier numerical simulations. Curiously, however, it is shown that the net vertical momentum associated with the blob increases linearly in time, despite the fact that the vertical velocity at the front of the thermal is constant. As with the swirling blob, an imposed magnetic field inhibits the formation of a vortex sheet. A strong magnetic field completely suppresses the phenomenon, replacing it with an axial diffusion of momentum, while a weak magnetic field allows the sheet to form, but places a lower bound on its thickness. The magnetic field does not, however, change the net vertical momentum of the blob, which always increases linearly with time.

Davidson, P. A.; Sreenivasan, Binod; Aspden, A. J.

2007-02-01

125

Comprehensive modeling of turbulent flames with the coherent flame-sheet model. Part 1: Buoyant diffusion flames  

SciTech Connect

A modified version of the computational fluid dynamics code KIVA-II was used to model the transient behavior of buoyant turbulent diffusion flames burning in still air. Besides extensions to the range of permitted boundary conditions and the addition of buoyancy terms to the turbulence model, KIVA-II was augmented by a version of the coherent flame-sheet model, Tesner`s soot generation model, Magnussen`s soot oxidation model, and an implementation of the discrete transfer radiation model that included both banded and continuum radiation. The model captured many of the features of buoyant turbulent flames. Its predictions supported experimental observations regarding the presence and frequency of large-scale pulsations, and regarding axial distributions of temperature, velocity, and chemical species concentrations. The radial structure of the flame was less well represented. The axial radiative heat flux distribution from the flame highlighted deficiencies in the soot generation model, suggesting that a model of soot particle growth was required.

Blunsdon, C.A.; Beeri, Z.; Malalasekera, W.M.G.; Dent, J.C. [Loughborough Univ. of Technology (United Kingdom). Dept. of Mechanical Engineering

1996-03-01

126

Highly vesicular pumice generated by buoyant detachment of magma in subaqueous volcanism  

NASA Astrophysics Data System (ADS)

Many submarine caldera volcanoes are blanketed with deposits of highly vesicular pumice, typically attributed to vigorous explosive activity. However, it is challenging to relate volcanic products to specific eruptive styles in submarine volcanism. Here we document vesicularity and textural characteristics of pumice clasts dredged from the submarine Macauley volcano in the Kermadec arc, southwest Pacific Ocean. We find that clasts show a bimodal distribution, with corresponding differences in vesicle abundances and shapes. Specifically, we find a sharp mode at 91% vesicularity and a broad mode at 65-80%. Subordinate clasts show gradients in vesicularity. We attribute the bimodality to a previously undocumented eruptive style that is neither effusive nor explosive. The eruption rate is insufficient to cause magma to fragment explosively, yet too high to passively feed a lava dome. Instead, the magma foam buoyantly detaches at the vent and rises as discrete magma parcels, or blebs, while continuing to vesiculate internally. The blebs are widely distributed by ocean currents before they disintegrate or become waterlogged. This disintegration creates individual clasts from interior and rim fragments, yielding the bimodal vesicularity characteristics. We conclude that the generation and widespread dispersal of highly vesicular pumice in the marine environment does not require highly explosive activity.

Rotella, Melissa D.; Wilson, Colin J. N.; Barker, Simon J.; Wright, Ian C.

2013-02-01

127

Numerical simulation of 2D buoyant jets in ice-covered and temperature-stratified water  

NASA Astrophysics Data System (ADS)

A two-dimensional (2D) unsteady simulation model is applied to the problem of a submerged warm water discharge into a stratified lake or reservoir with an ice cover. Numerical simulations and analyses are conducted to gain insight into large-scale convective recirculation and flow processes in a cold waterbody induced by a buoyant jet. Jet behaviors under various discharge temperatures are captured by directly modeling flow and thermal fields. Flow structures and processes are described by the simulated spatial and temporal distributions of velocity and temperature in various regions: deflection, recirculation, attachment, and impingement. Some peculiar hydrothermal and dynamic features, e.g. reversal of buoyancy due to the dilution of a warm jet by entraining cold ambient water, are identified and examined. Simulation results show that buoyancy is the most important factor controlling jet behavior and mixing processes. The inflow boundary is treated as a liquid wall from which the jet is offset. Similarity and difference in effects of boundaries perpendicular and parallel to flow, and of buoyancy on jet attachment and impingement, are discussed. Symmetric flow configuration is used to de-emphasize the Coanda effect caused by offset.

Gu, Ruochuan

128

3D Mixing Inside a Neutrally Buoyant Drop Driven by Electrohydrodynamic Flows  

NASA Astrophysics Data System (ADS)

For a neutrally buoyant drop subjected to a uniform electric field, the internal flow is the well-known Taylor circulation. In Phys. Fluids 19 013102 (2007), we theoretically studied three dimensional mixing by periodically switching a uniform electric field through an angle ?. Periodically switching the field is equivalent to periodically changing the symmetry axis of the Taylor circulation. For ?=0.5 ?, there is no chaotic mixing because the common heteroclinic trajectories form the separatrix of the flow. For other switching angles, chaotic advection is generated due to perturbations of the heteroclinic trajectory. Experimental investigations of mixing were carried out using a nearly isopycnic silicone oil/castor oil system. For ?=0.5 ?, our experiments show the existence of symmetry planes. In addition, two blobs of particles are observed to maintain almost invariant shapes for very long time, indicating the absence of chaotic mixing, as predicted by the theory. For other switching angles, experiments show the penetration of symmetry planes by tracer particles. However it is difficult to draw definitive conclusions regarding chaotic mixing because of charge relaxation, long initial transients and drop translation effects.

Xu, Xiumei; Homsy, G. M.

2007-11-01

129

Buoyant instabilities in downward flow in a symmetrically heated vertical channel  

SciTech Connect

This study of the downward flow of nitrogen in a tall, partially heated vertical channel (upstream isothermal at T{sub in}*, heated region isothermal at T{sub s}* downstream adiabatic) shows the strong effects of buoyancy even for small temperature differences. Time-dependent oscillations including periodic flow reversals occur along the channel walls. Although the flow and heat transfer are asymmetric, the temperature and axial component of velocity show symmetric reflections at two times that are half a period apart and the lateral component of velocity shows antisymmetric reflections at the two times. There is strong interaction between the downward flow in the central region of the channel and the upward flow along the heated channel walls. At the top of the heated region, the upward buoyant flow turns toward the center of the channel and is incorporated into the downward flow. Along the channel centerline there are nonmonotonic variations of the axial component of velocity and temperature and a large lateral component of velocity that reverses direction periodically. Results are presented for Re = 219.7 and Gr/Re{sup 2} = 1.83, 8.0, and 13.7. The heat transfer and the frequency of the oscillations increases and the flow and temperature fields become more complex as Gr/Re{sup 2} increases. The results have applications to fiber drying, food processing, crystal growth, solar energy collection, cooling of electronic circuits, ventilation, etc.

Evans, G. [Sandia National Lab., Livermore, CA (United States); Greif, R. [Univ. of California, Berkeley, CA (United States)

1996-07-01

130

Hamiltonian Structure and Dynamics of a Neutrally Buoyant Rigid Sphere Interacting with Thin Vortex Rings  

NASA Astrophysics Data System (ADS)

In a previous paper, we presented a (noncanonical) Hamiltonian model for the dynamic interaction of a neutrally buoyant rigid body of arbitrary smooth shape with N closed vortex filaments of arbitrary smooth shape, modeled as curves, in an infinite ideal fluid in mathbb{R}^3. The setting of that paper was quite general, and the model abstract enough to make explicit conclusions regarding the dynamic behavior of such systems difficult to draw. In the present paper, we examine a restricted class of such systems for which the governing equations can be realized concretely and the dynamics examined computationally. We focus, in particular, on the case in which the body is a smooth sphere. The equations of motion and Hamiltonian structure of this dynamic system, which follow from the general model, are presented. Following this, we impose the constraint of axisymmetry on the entire system and look at the case in which the rings are all circles perpendicular to a common axis of symmetry passing through the center of the sphere. This axisymmetric model, in our idealized framework, is governed by ordinary differential equations and is, relatively speaking, easily integrated numerically. Finally, we present some plots of dynamic orbits of the axisymmetric system.

Shashikanth, Banavara N.; Sheshmani, Artan; Kelly, Scott David; Wei, Mingjun

2010-08-01

131

Large deforming buoyant embolus passing through a stenotic common carotid artery: a computational simulation.  

PubMed

Arterial embolism is responsible for the death of lots of people who suffers from heart diseases. The major risk of embolism in upper limbs is that the ruptured particles are brought into the brain, thus stimulating neurological symptoms or causing the stroke. We presented a computational model using fluid-structure interactions (FSI) to investigate the physical motion of a blood clot inside the human common carotid artery. We simulated transportation of a buoyant embolus in an unsteady flow within a finite length tube having stenosis. Effects of stenosis severity and embolus size on arterial hemodynamics were investigated. To fulfill realistic nonlinear property of a blood clot, a rubber/foam model was used. The arbitrary Lagrangian-Eulerian formulation (ALE) and adaptive mesh method were used inside fluid domain to capture the large structural interfacial movements. The problem was solved by simultaneous solution of the fluid and the structure equations. Stress distribution and deformation of the clot were analyzed and hence, the regions of the embolus prone to lysis were localized. The maximum magnitude of arterial wall shear stress during embolism occurred at a short distance proximal to the throat of the stenosis. Through embolism, arterial maximum wall shear stress is more sensitive to stenosis severity than the embolus size whereas role of embolus size is more significant than the effect of stenosis severity on spatial and temporal gradients of wall shear stress downstream of the stenosis and on probability of clot lysis due to clot stresses while passing through the stenosis. PMID:22365500

Vahidi, Bahman; Fatouraee, Nasser

2012-02-24

132

Experimental Studies for the characterization of the mixing processes in negative buoyant jets  

NASA Astrophysics Data System (ADS)

A negatively buoyant jet (NBJ) corresponds to the physical phenomenon that develops when a fluid is discharged upwards into a lighter environment or downwards into a heavier receptor fluid. In a NBJ the flow is initially driven mostly by the momentum, so it basically behaves as a simple jet released withthe same angle, while far from the outlet the buoyancy prevails, bending the jet axis down and making it similar to a plume. The coexistence in the same phenomenon of both the characteristics of simple jets and plumes makes the NBJs a phenomenon still not entirely explained but, considering also the numerous practical applications, very interesting to study. Here some of the experimental results are presented. The laboratory experiment were obtained on a model simulating a typical sea discharge of brine from desalination plants: a pipe laid down on the sea bottom, with orifices on its lateral wall, releasing brine (heavier than the sea water) with a certain angle to the horizontal, in order to increase the jet path before sinking to the seafloor. A non-intrusive image analysis technique, namely Feature Tracking Velocimetry, is applied to measure velocity fields, with the aim at understanding the influence of some non-dimensional parameters driving the phenomenon (e.g. Reynolds number, release angle) on the structure of the NBJ and of the turbulence.

Besalduch, L. A.; Badas, M. G.; Ferrari, S.; Querzoli, G.

2013-04-01

133

Inertial modes of a periodically forced buoyant drop attached to a capillary  

NASA Astrophysics Data System (ADS)

A drop of heptane attached to a capillary tip immersed in water is submitted to small amplitude volume oscillations. Its interface is imaged by means of a high-speed camera and its shape decomposed into spherical harmonics. The forcing frequency is varied over a large range including the frequencies of resonance of the three first modes of inertial shape oscillations. For a small drop, which remains almost spherical at rest, the geometrical constraint imposed by the attachment on the capillary tip causes the oscillation modes to be very different from those of a free drop. Surprisingly, the resonance of large drops is observed at the frequency predicted for a free, pure, and neutrally buoyant drop and mainly involves a single spherical harmonic; only the damping rate is observed to be moderately larger. Since it gives rise to oscillations close to this ideal case, the present experimental method could be used, complementary to quasi-static oscillation of a pendant drop, to investigate dynamic interfacial tension at high frequency of various fluid systems.

Chebel, Nicolas Abi; Risso, Frédéric; Masbernat, Olivier

2011-10-01

134

The Three-dimensional Evolution of Buoyant Magnetic Flux Tubes in a Model Solar Convective Envelope  

NASA Astrophysics Data System (ADS)

We present a set of three-dimensional spherical shell anelastic MHD simulations of the buoyant rise of magnetic flux tubes from the base of the convection zone to a depth of 16 Mm below the photosphere. It is found that when a twisted flux tube arches upward due to buoyancy, it rotates out of the plane and thus produces a tilt at the apex. Our simulations show that for tubes with the twist rate that is necessary for a cohesive rise, the twist-induced tilt dominates that caused by the Coriolis force, and furthermore, the twist-induced tilt is of the wrong direction (opposite to the observational Joy's law) if the twist is left-handed (right-handed) in the northern (southern) hemisphere, following the observed hemispheric preference of the sign of the active region twist. It is found that in order for the emerging tube to show the correct tilt direction (consistent with observations), the initial twist rate of the flux tube needs to be less than half of that needed for a cohesive rise. Under such conditions, severe flux loss is found during the rise. We also found that due to the asymmetric stretching of the rising tube by the Coriolis force, a field strength asymmetry develops, with the field in the leading leg (leading in the direction of rotation) of the ?-shaped emerging tube being stronger than the field in the following leg, which results in a more compact morphology in the leading polarity of the emerging active region.

Fan, Y.

2008-03-01

135

Preliminary results of a numerical-experimental study of the dynamic structure of a buoyant jet diffusion flame  

Microsoft Academic Search

Preliminary results of a joint numerical-experimental investigation of the dynamic structure of a buoyant jet diffusion flame are presented. The purpose of this effort is to determine the nature of the unsteady interactions between flames and their associated vortex motions. A direct numerical simulation of an unsteady low-speed propane-air jet diffusion flame is carried out utilizing the flame sheet and

R. W. Davis; E. F. Moore; W. M. Roquemore; L. D. Chen; V. Vilimpoc; L. P. Goss

1991-01-01

136

The influence of wind-induced mixing on the vertical distribution of buoyant and sinking phytoplankton species  

Microsoft Academic Search

In this study we exploit recent advances in high-resolution autonomous monitoring to investigate the impact of short-term\\u000a variations in wind-induced mixing on the surface biomass and vertical distribution of buoyant and sinking phytoplankton species.\\u000a An autonomous platform (the Automatic Water Quality Monitoring Station) moored in a Mediterranean reservoir provided minute-by-minute\\u000a records of wind speed and the phytoplankton fluorescence during winter

Enrique Moreno-Ostos; Luis Cruz-Pizarro; Ana Basanta; D. Glen George

2009-01-01

137

Turbulent dispersion of slightly buoyant oil droplets and turbulent breakup of crude oil droplets mixed with dispersants  

Microsoft Academic Search

In part I, high speed in-line digital holographic cinematography is used for studying turbulent diffusion of slightly buoyant 0.5-1.2 mm diameter diesel droplets (specific gravity of 0.85) and 50 mum diameter neutral density particles. Experiments are performed in a 50x50x70 mm3 sample volume in a controlled, nearly isotropic turbulence facility, which is characterized by 2-D PIV. An automated tracking program

Balaji Gopalan

2010-01-01

138

Nonane droplet combustion with and without buoyant convection: Flame structure, burning rate and extinction in air and helium  

Microsoft Academic Search

The burning and extinction characteristics of isolated small nonane droplets are examined in a buoyant convective environment and in an environment with no external axial convection (as created by doing experiments at low gravity) to promote spherical droplet flames. The ambience is air and a mixture of 30%O2\\/70%He to assess the influence of soot formation. The initial droplet diameter (Do)

J. H. Bae; C. T. Avedisian

2009-01-01

139

PLIF and PIV measurements of the self-preserving structure of steady round buoyant turbulent plumes in crossflow  

Microsoft Academic Search

Measurements of the mean concentration of source fluid and mean velocity fields were obtained for the first time in the self-preserving region of steady round buoyant turbulent plumes in uniform crossflows using Planar-Laser-Induced-Fluorescence (PLIF) and Particle-Image-Velocimetry (PIV), respectively. The experiments involved salt water sources injected into water\\/ethanol crossflows within a water channel. Matching the index of refraction of the source

F. J. Diez; L. P. Bernal; G. M. Faeth

2005-01-01

140

46 CFR 160.052-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.  

Code of Federal Regulations, 2011 CFR

...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Plastic Foam, Adult and Child § 160.052-3a MaterialsâDee ring and snap hook assemblies and other instruments of...

2011-10-01

141

The Effects of Neutrally Buoyant, Externally Attached Transmitters on Swimming Performance and Predator Avoidance of Juvenile Chinook Salmon  

SciTech Connect

The presence of an externally attached telemetry tag is often associated with the potential for impaired swimming performance (i.e., snags and drag) as well as increased susceptibility to predation, specifically for smaller fish. The effects on swimming performance due to the presence of a neutrally buoyant externally attached acoustic transmitter were examined by comparing critical swimming speeds (Ucrit) for juvenile Chinook salmon tagged with two different neutrally buoyant external transmitters (Type A and B), nontagged individuals, and those surgically implanted with the current JSATS acoustic transmitter. Fish tagged with the Type A and B designs had lower Ucrit when compared to nontagged individuals. However, there was no difference in Ucrit among fish tagged with Type A or B designs compared to those with surgically implanted tags. Further testing was then conducted to determine if predator avoidance ability was affected due to the presence of Type A tags when compared to nontagged fish. No difference was detected in the number of tagged and nontagged fish consumed by rainbow trout throughout the predation trials. The results of this study support the further testing on the efficacy of a neutrally buoyant externally attached telemetry tag for survival studies involving juvenile salmonids passing through hydro turbines.

Janak, Jill M.; Brown, Richard S.; Colotelo, Alison HA; Pflugrath, Brett D.; Stephenson, John R.; Deng, Zhiqun; Carlson, Thomas J.; Seaburg, Adam

2012-08-01

142

Genetic Affinities between Trans-Oceanic Populations of Non-Buoyant Macroalgae in the High Latitudes of the Southern Hemisphere  

PubMed Central

Marine biologists and biogeographers have long been puzzled by apparently non-dispersive coastal taxa that nonetheless have extensive transoceanic distributions. We here carried out a broad-scale phylogeographic study to test whether two widespread Southern Hemisphere species of non-buoyant littoral macroalgae are capable of long-distance dispersal. Samples were collected from along the coasts of southern Chile, New Zealand and several subAntarctic islands, with the focus on high latitude populations in the path of the Antarctic Circumpolar Current or West Wind Drift. We targeted two widespread littoral macroalgal species: the brown alga Adenocystisutricularis (Ectocarpales, Heterokontophyta) and the red alga Bostrychiaintricata (Ceramiales, Rhodophyta). Phylogenetic analyses were performed using partial mitochondrial (COI), chloroplast (rbcL) and ribosomal nuclear (LSU / 28S) DNA sequence data. Numerous deeply-divergent clades were resolved across all markers in each of the target species, but close phylogenetic relationships – even shared haplotypes – were observed among some populations separated by large oceanic distances. Despite not being particularly buoyant, both Adenocystisutricularis and Bostrychiaintricata thus show genetic signatures of recent dispersal across vast oceanic distances, presumably by attachment to floating substrata such as wood or buoyant macroalgae.

Fraser, Ceridwen I.; Zuccarello, Giuseppe C.; Spencer, Hamish G.; Salvatore, Laura C.; Garcia, Gabriella R.; Waters, Jonathan M.

2013-01-01

143

The Three-dimension Evolution Of Buoyant Magnetic Flux Tubes In The Solar Convective Envelope  

NASA Astrophysics Data System (ADS)

We present a set of 3D spherical shell anelastic MHD simulations of the buoyant rise of magnetic flux tubes through the solar convective envelope (up to a depth of 20Mm below the photosphere). It is found that a twisted flux tube when arched upward due to buoyancy will develop a writhe of the tube axis and thus produce a tilt at the apex. This twist induced tilt is counter-clockwise (clock-wise) when viewed from the top for a flux tube with a left-handed (right-handed) twist. On the other hand, the Coriolis force acting on the diverging, expanding motion at the apex of a rising flux tube will drive a clock-wise (counter-clock-wise) tilt at the tube apex in the northern (southern) hemisphere. Our present 3D MHD simulations show that for tubes with a twist rate that is necessary for a cohesive rise, the twist induced tilt dominates that caused by the Coriolis force, and furthermore, the twist induced tilt is of the wrong direction (opposite to the observed Joy's law) if the twist is left-handed (right-handed) in the northern (southern) hemisphere following the observed hemispheric preference of the sign of active region twist. It is found that in order for the emerging flux tube to show the correct tilt direction (consistent with observations), the initial twist rate of the flux tube needs to be less than a half of that needed for a cohesive rise. We also found that a field strength asymmetry develops with the field in the leading leg (leading in the direction of rotation) of the Omega-shaped emerging tube being stronger than the following, resulting in a more compact flux distribution and a higher peak field strength in the leading polarity of the emerging active region.

Fan, Yuhong

2007-05-01

144

Northern Monterey Bay upwelling shadow front: Observations of a coastally and surface-trapped buoyant plume  

NASA Astrophysics Data System (ADS)

During the upwelling season in central California, northwesterly winds along the coast produce a strong upwelling jet that originates at Point Año Nuevo and flows southward across the mouth of Monterey Bay. A convergent front with a mean temperature change of 3.77 ± 0.29°C develops between the warm interior waters and the cold offshore upwelling jet. To examine the forcing mechanisms driving the location and movement of the upwelling shadow front and its effects on biological communities in northern Monterey Bay, oceanographic conditions were monitored using cross-shelf mooring arrays, drifters, and hydrographic surveys along a 20 km stretch of coast extending northwestward from Santa Cruz, California, during the upwelling season of 2007 (May-September). The alongshore location of the upwelling shadow front at the northern edge of the bay was driven by: regional wind forcing, through an alongshore pressure gradient; buoyancy forces due to the temperature change across the front; and local wind forcing (the diurnal sea breeze). The upwelling shadow front behaved as a surface-trapped buoyant current, which is superimposed on a poleward barotropic current, moving up and down the coast up to several kilometers each day. We surmise that the front is advected poleward by a preexisting northward barotropic current of 0.10 m s-1 that arises due to an alongshore pressure gradient caused by focused upwelling at Point Año Nuevo. The frontal circulation (onshore surface currents) breaks the typical two-dimensional wind-driven, cross-shelf circulation (offshore surface currents) and introduces another way for water, and the material it contains (e.g., pollutants, larvae), to go across the shelf toward shore.

Woodson, C. B.; Washburn, L.; Barth, J. A.; Hoover, D. J.; Kirincich, A. R.; McManus, M. A.; Ryan, J. P.; Tyburczy, J.

2009-12-01

145

Three-Dimensional Magnetohydrodynamic Simulations of Buoyant Bubbles in Galaxy Clusters  

NASA Astrophysics Data System (ADS)

We report results of three-dimensional magnetohydrodynamic simulations of the dynamics of buoyant bubbles in magnetized galaxy cluster media. The simulations are three-dimensional extensions of two-dimensional calculations reported by Jones and De Young. Initially, spherical bubbles and briefly inflated spherical bubbles all with radii a few times smaller than the intracluster medium (ICM) scale height were followed as they rose through several ICM scale heights. Such bubbles quickly evolve into a toroidal form that, in the absence of magnetic influences, is stable against fragmentation in our simulations. This ring formation results from (commonly used) initial conditions that cause ICM material below the bubbles to drive upwards through the bubble, creating a vortex ring; that is, hydrostatic bubbles develop into "smoke rings," if they are initially not very much smaller or very much larger than the ICM scale height. Even modest ICM magnetic fields with ? = P gas/P mag lsim 103 can influence the dynamics of the bubbles, provided the fields are not tangled on scales comparable to or smaller than the size of the bubbles. Quasi-uniform, horizontal fields with initial ? ~ 102 bifurcated our bubbles before they rose more than about a scale height of the ICM, and substantially weaker fields produced clear distortions. These behaviors resulted from stretching and amplification of ICM fields trapped in irregularities along the top surface of the young bubbles. On the other hand, tangled magnetic fields with similar, modest strengths are generally less easily amplified by the bubble motions and are thus less influential in bubble evolution. Inclusion of a comparably strong, tangled magnetic field inside the initial bubbles had little effect on our bubble evolution, since those fields were quickly diminished through expansion of the bubble and reconnection of the initial field.

O'Neill, S. M.; De Young, D. S.; Jones, T. W.

2009-04-01

146

Aerobic respiratory costs of swimming in the negatively buoyant brief squid Lolliguncula brevis.  

PubMed

Because of the inherent inefficiency of jet propulsion, squid are considered to be at a competitive disadvantage compared with fishes, which generally depend on forms of undulatory/oscillatory locomotion. Some squid, such as the brief squid Lolliguncula brevis, swim at low speeds in shallow-water complex environments, relying heavily on fin activity. Consequently, their swimming costs may be lower than those of the faster, more pelagic squid studied previously and competitive with those of ecologically relevant fishes. To examine aerobic respiratory swimming costs, O(2) consumption rates were measured for L. brevis of various sizes (2-9 cm dorsal mantle length, DML) swimming over a range of speeds (3-30 cm s(-1)) in swim tunnel respirometers, while their behavior was videotaped. Using kinematic data from swimming squid and force data from models, power curves were also generated. Many squid demonstrated partial (J-shaped) or full (U-shaped) parabolic patterns of O(2) consumption rate as a function of swimming speed, with O(2) consumption minima at 0.5-1.5 DML s(-1). Power curves derived from hydrodynamic data plotted as a function of swimming speed were also parabolic, with power minima at 1.2-1.7 DML s(-1). The parabolic relationship between O(2) consumption rate/power and speed, which is also found in aerial flyers such as birds, bats and insects but rarely in aquatic swimmers because of the difficulties associated with low-speed respirometry, is the result of the high cost of generating lift and maintaining stability at low speeds and overcoming drag at high speeds. L. brevis has a lower rate of O(2) consumption than the squid Illex illecebrosus and Loligo opalescens studied in swim tunnel respirometers and is energetically competitive (especially at O(2) consumption minima) with fishes, such as striped bass, mullet and flounder. Therefore, the results of this study indicate that, like aerial flyers, some negatively buoyant nekton have parabolic patterns of O(2) consumption rate/power as a function of speed and that certain shallow-water squid using considerable fin activity have swimming costs that are competitive with those of ecologically relevant fishes. PMID:11719530

Bartol, I K; Mann, R; Patterson, M R

2001-11-01

147

Is the 'Fast Halo' around Hawaii as imaged in the PLUME experiment direct evidence for buoyant plume-fed asthenosphere?  

NASA Astrophysics Data System (ADS)

An intriguing spatial pattern of variations in shear-wave arrival times has been mapped in the PLUME ocean bottom experiment (Wolfe et al., 2009) around Hawaii. The pattern consists of a halo of fast travel times surrounding a disk of slow arrivals from waves traveling up though the plume. We think it is directly sensing the pattern of dynamic uplift of the base of a buoyant asthenosphere - the buoyancy of the plume conduit lifting a 'rim' of the cooler, denser mantle that the plume rises through. The PLUME analysis inverted for lateral shear velocity variations beneath the lithosphere, after removing the assumed 1-D model velocity structure IASP91. They found that a slow plume-conduit extends to at least 1200 km below the Hawaiian hotspot. In this inversion the slow plume conduit is — quite surprisingly - surrounded by a fast wavespeed halo. A fast halo is impossible to explain as a thermal halo around the plume; this should lead to a slow wavespeed halo, not a fast one. Plume-related shearwave anisotropy also cannot simply explain this pattern — simple vertical strain around the plume conduit would result in an anisotropic slow shear-wavespeed halo, not a fast one. (Note the PLUME experiment’s uniform ‘fast-halo’ structure from 50-400km is likely to have strong vertical streaking in the seismic image; Pacific Plate-driven shear across a low-viscosity asthenosphere would be expected to disrupt and distort any cold sheet of vertical downwelling structure between 50-400km depths so that it would no longer be vertical as it is in the 2009 PLUME image with its extremely poor vertical depth control.) If the asthenosphere is plume-fed, hence more buoyant than underlying mantle, then there can be a simple explanation for this pattern. The anomaly would be due to faster traveltimes resulting from dynamic relief at the asthenosphere-mesosphere interface; uplift of the denser mesosphere by the buoyancy of the rising plume increases the distance a wave travels through faster mantle and reduces the distance though the slower asthenosphere. With this interpretation, the inference of a radially symmetric ~40-70 km high-~250 km-radius ‘bump’ of uplift of the base of buoyant plume-fed asthenosphere (PFA) can be directly estimated from PLUME results and the measured ~6-10% reduction in shear velocity between the PFA and underlying mantle. The inferred dynamic relief at the base of the PFA due to buoyancy within the underlying plume conduit is strikingly similar to the relief we find in recent axisymmetric 2D and Cartesian 3-D numerical experiments that explore the dynamics of mantle convection with a PFA. The width and height of the bump scale directly with the total buoyancy anomaly in the upper ~500km of the plume conduit, we discuss numerical experiments that quantify this relationship, show that it is, to first order, independent of the viscosity of material in the plume conduit or asthenosphere, and which also quantify the ~400km-radius geoid anomaly produced by these subasthenospheric mantle density anomalies. This effect can only happen if the asthenosphere is more buoyant than underlying mantle — and is therefore direct evidence that a buoyant plume-fed asthenosphere exists around Hawaii.

Morgan, J. P.; Shi, C.; Hasenclever, J.

2010-12-01

148

Preliminary results of a numerical-experimental study of the dynamic structure of a buoyant jet diffusion flame  

SciTech Connect

Preliminary results of a joint numerical-experimental investigation of the dynamic structure of a buoyant jet diffusion flame are presented. The purpose of this effort is to determine the nature of the unsteady interactions between flames and their associated vortex motions. A direct numerical simulation of an unsteady low-speed propane-air jet diffusion flame is carried out utilizing the flame sheet and conserved variable approximations. Counterrotating vortex structures internal and external to the flame surface appear and move upward along with flame sheet bulges. Tip-cutting (flickering) occurs with a frequency of 11-15 Hz. These dynamic features bear close resemblance to those observed experimentally by means of the reactive Mie scattering (RMS) technique. Comparisons between computational and experimental (determined using thin filament pyrometry) near-zero gravity in the computation results in the complete cessation of dynamical activity, thus demonstrating the important role that buoyancy plays in the behavior of this flame.

Davis, R.W.; Moore, E.F. (Center for Chemical Technology, National Inst. of Standards and Technology, Gaithersburg, MD (US)); Roquemore, W.M. (WRDC/Aero Propulsion Lab., Wright-Patterson AFB, OH (US)); Chen, L.D. (Dept. of Mechanical Engineering, Univ. of Iowa, Iowa City, IA (US)); Vilimpoc, V.; Goss, L.P. (Systems Research Lab., Inc., Dayton, OH (US))

1991-02-01

149

Relation between shape of liquid-gas interface and evolution of buoyantly unstable three-dimensional chemical fronts  

NASA Astrophysics Data System (ADS)

Buoyantly unstable 3D chemical fronts were seen traveling through an iodate-arsenous acid reaction solution. The experiments were performed in channel reactors with rectangular cross sections, where the top of the reaction solution was in contact with air. A concave or convex meniscus was pinned to reactor lateral walls. Influence of the meniscus shape on front development was investigated. For the concave meniscus, an asymptotic shape of fronts holding negative curvature was observed. On the other hand, fronts propagating in the solution with the convex meniscus kept only positive curvature. Those fronts were also a bit faster than fronts propagating in the solution with the concave meniscus. A relation between the meniscus shape, flow distribution, velocity, and shape is discussed.

Šebestíková, L.

2013-09-01

150

46 CFR 160.060-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.  

Code of Federal Regulations, 2010 CFR

...of closure for buoyant vests mustâ (1) Be tested for weathering. The Coast Guard will determine which one or more of the...hours; and (2) Within 5 minutes of completion of the weathering test required by paragraph (b)(1) of this...

2009-10-01

151

A Spatially Developing One-Dimensional Turbulence (ODT) Study of Soot and Enthalpy Evolution in Meter-Scale Buoyant Turbulent Flames  

Microsoft Academic Search

The interaction between soot and enthalpy evolution in a buoyant turbulent flame, exhibiting key attributes of a fire, is studied using a novel approach. This approach is based on a spatially evolving form of the one-dimensional turbulence (ODT) model that resolves the full range of scales, in a single spatial dimension, from the scale of the plume evolution to that

Allen J. Ricks; John C. Hewson; Alan R. Kerstein; Jay P. Gore; Sheldon R. Tieszen; William T. Ashurst

2010-01-01

152

Buoyant replenishment in silicic magma reservoirs: Experimental approach and implications for magma dynamics, crystal mush remobilization, and eruption  

NASA Astrophysics Data System (ADS)

We present new experiments on replenishment of rhyolite magma chambers by rhyolite magma using corn syrup-water solutions. We emphasize small density contrasts and show that buoyancy is the key controlling factor for whether injections will rise to the top (if buoyant) or pond at the base (if denser). During emplacement, we observe little or no mixing of the injected liquid with the reservoir liquid, as predicted by the fact that our injections have low Reynolds numbers (<10, typically). At later stages, the low-buoyancy (?1 kg m-3) injected liquid, which has accumulated at the top of the reservoir, undergoes mixing with the reservoir liquid, which may originate by the gravitational destabilization of a thin layer of denser resident liquid trapped above the injected liquid layer. The presence of a basal crystal mush, modeled by acrylic beads in a corn syrup-water solution matrix is also considered. Slightly buoyant injections entrain a small fraction of mush particles to the top of the overlying liquid layer. Entrainment efficiency increases dramatically for high-buoyancy injections. We hypothesize that the injected liquid can entrain a maximum quantity of mush particles, which corresponds to the amount required for the injected liquid/mush particle suspension to attain neutral buoyancy in the resident liquid. Hence for silicic systems, a replenishing melt can entrain up to 12.5% crystals during its ascent through the mush. Our results have implications for rhyolites bearing crystals with disequilibrium features, as they may represent mush crystals remobilized by a replenishing silicic magma.

Girard, Guillaume; Stix, John

2009-08-01

153

Simulations of Supernova Remnants in Diffuse Media. III. The Population of Buoyant Remnants above the Milky Way's Disk  

NASA Astrophysics Data System (ADS)

We model SNRs at a variety heights above the disk with a detailed numerical simulation that includes nonequilibrium ionization and recombination and follows the remnants' evolution until their hot bubbles have cooled. We analytically calculate the bubbles' buoyant acceleration and frictional drag. From the simulation results, combined with the rates for isolated supernova explosions above a height of 130 pc, we estimate the time and space average O+5, N+4, and C+3 column densities and emission intensities, 1/4 keV soft X-ray surface brightness, area coverage, and volume occupation due to the population of isolated SNRs above the Galaxy's H I layer. Irrespective of assumed supernova explosion energy, ambient nonthermal pressure, or frictional drag coefficient used in the calculations, the predicted O+5 column density as a function of height matches the observed distribution between 130 and 2000 pc. The O VI resonance line emission (??1032, 1038) contributes significantly to the average observed intensity. Assuming our modest supernova explosion rate, the population of isolated extraplanar SNRs can explain 80% of the observed 1/4 keV surface brightness attributed to the extraplanar gas beyond the H I layer in the southern hemisphere. Within the range of uncertainty in the SN rate, such SNRs can explain all of this observed emission (400×10-6 counts s-1 arcmin-2). Thus, extraplanar SNRs could be the most important sources of hot gas between the Local Bubble and z~2000 pc in the relatively quiescent southern hemisphere. These results stand whether the remnants are assumed to be buoyant or not. The population of old extraplanar SNRs should cover most, but not all of the high-latitude sky, thus explaining the mottled appearance of the soft X-ray maps (outside of superbubbles). Bright young extraplanar SNRs should cover less than 1% of the high-latitude sky. Perhaps the l=247°, b=-64° crescent in the 1/4 keV X-ray maps could be such a remnant.

Shelton, R. L.

2006-02-01

154

Laboratory and numerical model studies of a negatively-buoyant jet discharged horizontally into a homogeneous rotating fluid  

NASA Astrophysics Data System (ADS)

The results of laboratory experiments and numerical model simulations are described in which the motion of a round, negatively-buoyant, turbulent jet discharged horizontally above a slope into a rotating homogeneous fluid has been investigated. For the laboratory study, flow visualisation data are presented to show the complex three-dimensional flow fields generated by the discharge. Analysis of the experimental data indicates that the spatial and temporal developments of the flow field are controlled primarily by the lateral and vertical discharge position of the jet (with respect to the bounding surfaces of the container of width W) and the specific momentum (M0) and buoyancy (B0) fluxes driving the jet. The flow is seen to be characterised by the formation of (i) a primary anticyclonic eddy (PCC) close to the source, (ii) an associated secondary cyclonic eddy (SCE) and (iii) a buoyancy-driven bottom boundary current along the right side boundary wall. For the parameter ranges studied, the size Lp, s and spatial location xp, s of the PCC and SCE (and the nose velocity uN of the boundary current) are shown to be only weakly-dependent upon the value of the mixed parameter M0?/B0, where ? is the background rotation rate. Both Lp and xp are shown to scale with the separation distance y*/W of the right side wall (y = 0) from the source (y = y*), both Ls and xs scale satisfactorily with the length scale lM (= M03/4/B0½) and uN is determined by the appropriate gravity current speed [(g']0H]½ and the separation distance y*/W. Numerical model results show good qualitative agreement with the laboratory data with regard to the generation of the PCC, SCE and boundary current as characteristic features of the flow in question. In addition, extension of the numerical model to diagnose potential vorticity and plume thickness distributions for the laboratory cases allow the differences in momentum-and buoyancy-dominated flows to be clearly delineated. Specifically, the characteristic features of the SCE are shown to be strongly dependent upon the value of ?/B0 for the buoyant jet flow; not least, the numerical model data are able to confirm the controlling role played by the boundary walls in the laboratory experiments. Quantitative agreement between the numerical and laboratory model data is fair; most significantly, the success of the former model in simulating the dominant flow features from the latter enables the reliable extension of the numerical model to be made to cases of direct oceanic interest.

Davies, Peter A.; Käse, Rolf H.; Ahmed, Iftikhar

155

Lab-on-a-bubble: synthesis, characterization, and evaluation of buoyant gold nanoparticle-coated silica spheres.  

PubMed

This paper describes the development and preparation of a new class of materials for surface-enhanced Raman scattering (SERS) consisting of gold nanoparticles coated onto hollow, buoyant silica microspheres. These materials allow for a new type of molecular assay designated as a lab-on-a-bubble (LoB). LoB materials serve as a convenient platform for the detection of analytes in solution and offer several advantages over traditional colloidal gold and planar SERS substrates, such as the ability to localize and concentrate analytes for detection. An example assay is presented using the LoB method and cyanide detection. Cyanide binds to SERS-active, gold-coated LoBs and is detected directly from the corresponding SERS signal. The abilities of LoBs and a gold colloid to detect cyanide are compared, and in both cases, a detection limit of ~170 ppt was determined. Differences in measurement error using LoBs versus gold colloid are also described, as well as an assay for 5,5'-dithiobis(2-nitrobenzoic acid) that shows the benefit of using LoBs over SERS analyses in colloids, which are often plagued by particle aggregation. PMID:22077992

Schmit, Virginia L; Martoglio, Richard; Scott, Brandon; Strickland, Aaron D; Carron, Keith T

2011-11-18

156

Modeling possible spreadings of a buoyant surface plume with lagrangian and eulerian approaches at different resolutions using flow syntheses from 1992-2007 - a Gulf of Mexico study  

Microsoft Academic Search

We present results from an ensemble of BP oil spill simulations. The oil spill slick is modeled as a buoyant surface plume that is transported by ocean currents modulated, in some experiments, by surface winds. Ocean currents are taken from ECCO2 project (see http:\\/\\/ecco2.org ) observationally constrained state estimates spanning 1992-2007. In this work we (i) explore the role of

R. Tulloch; C. N. Hill; O. Jahn

2010-01-01

157

Horizontal laminar flow of coarse nearly-neutrally buoyant particles in non-Newtonian conveying fluids: CFD and PEPT experiments compared  

Microsoft Academic Search

The horizontal flow of coarse particle suspensions in non-Newtonian carrier fluids was numerically simulated using an Eulerian–Eulerian CFD model. This study was concerned with nearly-neutrally buoyant particles of 5 and 10mm diameter conveyed by fluids of Ellis rheology in laminar flow, in a 45mm diameter pipe at concentrations up to 41% v\\/v. CFD predictions of solid phase velocity profiles and

M. Eesa; M. Barigou

2008-01-01

158

Telecon with Dendreon - Provenge, 6/12/2007  

Center for Biologics Evaluation and Research (CBER)

Text Version... Currently, they have shipping data to Chicago, Ohio, and some east coast destinations from the NJ facility, but not sure how helpful that will be. ... More results from www.fda.gov/downloads/biologicsbloodvaccines/cellulargenetherapyproducts

159

Dendreon – sipuleucel-T (Provenge) - BLA STN 125197  

Center for Biologics Evaluation and Research (CBER)

Text Version... Page 2. - Histologically, collagen and elastin in scars can be ... The current collagen assay measures total collagen content in the final product ... More results from www.fda.gov/downloads/biologicsbloodvaccines/cellulargenetherapyproducts

160

Dendreon – Sipuleucel-T (Provenge) - BLA STN 125197 ...  

Center for Biologics Evaluation and Research (CBER)

... T (Provenge) - BLA STN 125197 For the treatment of men with asymptomatic ... Wilson Bryan Robert Ball Faith Barash Robert Wise Craig Zinderman ... More results from www.fda.gov/biologicsbloodvaccines/cellulargenetherapyproducts/approvedproducts

161

The relative importance of local retention and inter-reef dispersal of neutrally buoyant material on coral reefs  

NASA Astrophysics Data System (ADS)

Reef-scale, eddy-resolving numerical models are applied to discriminate between local trapping of neutrally buoyant passive material coming from a natal reef versus trapping of this material on reefs downstream. A hydrodynamic model is coupled with a Lagrangian (nongridded) dispersal simulation to map the movement of material such as passive larvae within and between natural reefs. To simplify the interpretation, a number of schematic reef shapes, sizes and spacings were devised to represent the most common cases typifying Australia's Great Barrier Reef. Prior investigations have shown that coral reefs on the Great Barrier Reef may retain material for times equivalent to the pelagic dispersal period of many species. This paper explores whether larvae are more likely to settle on the natal reef, settle downstream or fail to settle at all. The modelling neglects active larval behaviour and treats the vertically well-mixed case of notionally weightless particles only. The crown-of-thorns starfish larvae with a pelagic dispersal period of at least 10 days are one example of this case. Larvae are most likely to be found near the natal reef rather than its downstream neighbour, mostly because the currents take the vertically well-mixed material around, rather than onto, the downstream reef. Of all the simulations, the highest numbers were found on natal reefs (e.g. 8% after 10 days) while downstream numbers mostly varied between 0 and 1% after 10 days. Particle numbers equalised only when spacing between the two reefs was less than the reef length (6 km), or when the downstream reef was in the direct path of the larval stream.

Black, Kerry P.

1993-03-01

162

Ethyl cellulose and hydroxypropyl methyl cellulose buoyant microspheres of metoprolol succinate: Influence of pH modifiers  

PubMed Central

Introduction: Incorporation of pH modifier has been the usual strategy employed to enhance the dissolution of weakly basic drug from floating microspheres. Microspheres prepared using a combination of both ethyl cellulose (EC) and hydroxypropyl methylcellulose (HPMC) which shows highest release were utilize to investigate the effect of fumaric acid (FA), citric acid (CA), ascorbic acid (AA) and tartaric acid (TA) (all 5-20% w/w) incorporation on metoprolol succinate (MS) release. Materials and Methods: EC, HPMC alone or in combination were used to prepare microspheres that floated in simulated gastric fluid and evaluated for a percent yield, drug entrapment, percent buoyancy and drug release. The higher drug release in combination (MS:HPMC:EC, 1:1:2) was selected for the evaluation of influence of pH modifiers on MS release. CA (5-20% w/w), AA (5-20% w/w), FA (5-20% w/w) and TA (5-20% w/w) were added and evaluated for drug release. Present investigation is directed to develop floating drug delivery system of MS by solvent evaporation technique. Results: The microspheres of MS:HPMC:EC (1:1:2) exhibited the highest entrapment (74.36 ± 2.18). The best percentage yield was obtained at MS:HPMC (1:1) (83.96 ± 1.50) and combination of MS:HPMC:EC (1:1:2) (79.23 ± 1.63). Conclusion: MS release from the prepared microspheres was influenced by changing MS-polymer, MS-polymer-polymer ratio and pH modifier. Although significant increment in MS release was observed with CA (20% w/w), TA (20% w/w) and AA (20% w/w), addition of 20% w/w FA demonstrated more pronounced and significant increase in drug entrapment as well as release from MS:HPMC:EC (1:1:2) buoyant microspheres.

Raut, Neha S; Somvanshi, Sachin; Jumde, Amol B; Khandelwal, Harsha M; Umekar, Milind J; Kotagale, Nandkishor Ramdas

2013-01-01

163

Buoyant Ekman Layer.  

National Technical Information Service (NTIS)

The solution of a steady-state, baroclinic boundary layer over a two-dimensional terrain in an f plane is obtained. The boundary-layer thickness is found to be dependent on both the stability S = (alpha sub m)g((T sub m/H) + (g/C sub p))/(4(omega squared)...

Y. Hsueh

1969-01-01

164

Buoyant Ekman Layer  

Microsoft Academic Search

The solution of a steady-state, baroclinic boundary layer over a two-dimensional terrain in an f plane is obtained. The boundary-layer thickness is found to be dependent on both the stability S = ?mg[(Tm?H) + (g?cp)] (4?2L)?1 and the terrain slope. For a given terrain slope ? and Prandtl number ? = ??k, a critical value of the stability parameter S

Y. Hsueh

1969-01-01

165

Integral buoyant riser  

Microsoft Academic Search

This patent describes a riser string extending upwardly from a subsea location, comprising in combination: a plurality of outer conduits; a plate secured to each end of each outer conduit, each plate having a plurality of holes; a plurality of inner conduits extending through the outer conduits for conveying production and control fluids, each inner conduit having an end that

B. J. Watkins; A. M. Regan; B. L. Crager; G. L. Fox; R. C. Houlgrave

1987-01-01

166

Glasgow University's Buoyant Scheme.  

ERIC Educational Resources Information Center

LearningWorks, an employee development program for University of Glasgow staff, grants training allowances to pay for learning on their own time. In the first year, 43% of eligible employees participated in a wide range of accessible learning opportunities. (SK)

Maclachlan, Kathy

1998-01-01

167

Integral buoyant riser  

SciTech Connect

This patent describes a riser string extending upwardly from a subsea location, comprising in combination: a plurality of outer conduits; a plate secured to each end of each outer conduit, each plate having a plurality of holes; a plurality of inner conduits extending through the outer conduits for conveying production and control fluids, each inner conduit having an end that extends into one of the holes; port means in the outer conduits for admitting sea water into the outer conduits; gas injection means in the outer conduits for injecting gas into the outer conduits to provide a selected buoyancy in the riser string; and securing means for securing the outer conduits together with the adjacent plates of adjoining outer conduits in contact with each other. The plates are intrinsically formed with an outwardly protruding configuration, so that when compressed together by the securing means, they flatten and exert a preload compressive force across each other, causing the inner conduits to sealingly communicate with each other.

Watkins, B.J.; Regan, A.M.; Crager, B.L.; Fox, G.L.; Houlgrave, R.C.

1987-03-10

168

Near-field mixing of a vertical buoyant jet in a shallow crossflow: Implications on adsorption and flocculation  

NASA Astrophysics Data System (ADS)

The behaviour and movement of pulpmill pollutants discharged into the Northern Fraser River is of significant concern due to their potential impact on this valuable aquatic ecosystem. The shallow receiving water can influence the mixing and subsequent dilution of these discharges. The association of contaminants with suspended sediment, either by direct adsorption or flocculation of contaminated solids discharged with the effluent (biosolids), also affects pollutant fate. This study examined the effects of a shallow crossflow in the near field mixing of a vertical buoyant jet, specifically dilution and trajectory. Physical mixing experiments were carried out in a shallow ambient current over a range of conditions similar to those seen in the Fraser River, specifically peak and low flow conditions. The dilution and trajectory results were then compared to those predicted by CORMIX1. The mechanism of association of contaminants with suspended sediment under these near field conditions was also investigated. A jet classification scheme was developed based on the behaviour of the jets in the shallow crossflow. Jets were classified to be Bottom, Intermediate or Surface Jets. Bottom Jets were influenced primarily by interaction of the jet with the bottom boundary layer, resulting in significantly higher levels of dilution and possible bottom attachment. The mixing of Intermediate Jets was more complicated due to interaction with both the top and bottom boundaries: the free surface inhibited mixing while interactions with the boundary layer enhanced mixing. Surface Jets were drastically affected by the free surface, with a reduction in dilution due to impingement on the free surface. The CORMIX1 model was found to be unsuitable for predicting the dilution in this application since it does not consider the effects of either the free surface or the bottom boundary layer on jet mixing. Adsorption was found to play a limited role in the near field region. Of greater importance, is the potential for flocculation of biosolids with suspended sediment. The most important parameter in predicting where the conditions for this increased flocculation will occur was the ratio of the number of biosolid, particles to the number of suspended sediment particles.

Gomm, Leslie Sharon

1999-10-01

169

The Potential for Buoyant Displacement Gas Release Events in Tank 241-SY-102 after Waste Transfer from Tank 241-SY-101  

SciTech Connect

Tank 241-SY-101 is a double-shell radioactive waste storage tank containing waste that, before recent transfer and water back-dilution operations, was capable of retaining gas and producing flammable buoyant displacement gas release events (BD GREs). A BD GRE occurs when a portion of the nonconvective layer waste retains enough gas to become buoyant, rises to the waste surface, breaks up, and releases some of the stored gas. Installing the mixer pump in 1993 successfully mitigated gas retention in the settled solids layer in SY-101 and has prevented BD GREs. Gas retention in the floating drust layer and the corresponding accelerated waste level growth made it necessary to begin waste removal and back-dilution with water in December 1999. During these operations, some of the SY-101 mixed slurry layer is removed and transferred into Tank 241-SY-102. There was some concern that adding the SY-101 waste into SY-102 could create a waste configuration in SY-102 capable of BD GREs. This report updates and extends earlier assessments of the potential for BD GRE conditions in SY-102 after waste is transferred from SY-101. We determined that, under the given assumptions, no possibility of BD GREs exists in SY-102 from the SY-101 waste being added during from December 1999 through March 2000.

Wells, Beric E.; Meyer, Perry A.; Chen, Guang

2000-04-10

170

HGSYSTEM/UF{sub 6} model enhancements for plume rise and dispersion around buildings, lift-off of buoyant plumes, and robustness of numerical solver  

SciTech Connect

The HGSYSTEM/UF{sub 6} model was developed for use in preparing Safety Analysis Reports (SARs) by estimating the consequences of possible accidental releases of UF{sub 6} to the atmosphere at the gaseous diffusion plants (GDPs) located in Portsmouth, Ohio, and Paducah, Kentucky. Although the latter report carries a 1996 date, the work that is described was completed in late 1994. When that report was written, the primary release scenarios of interest were thought to be gas pipeline and liquid tank ruptures over open terrain away from the influence of buildings. However, upon further analysis of possible release scenarios, the developers of the SARs decided it was necessary to also consider accidental releases within buildings. Consequently, during the fall and winter of 1995-96, modules were added to HGSYSTEM/UF{sub 6} to account for flow and dispersion around buildings. The original HGSYSTEM/UF{sub 6} model also contained a preliminary method for accounting for the possible lift-off of ground-based buoyant plumes. An improved model and a new set of wind tunnel data for buoyant plumes trapped in building recirculation cavities have become available that appear to be useful for revising the lift-off algorithm and modifying it for use in recirculation cavities. This improved lift-off model has been incorporated in the updated modules for dispersion around buildings.

Hanna, S.R.; Chang, J.C.

1997-01-01

171

Modeling possible spreadings of a buoyant surface plume with lagrangian and eulerian approaches at different resolutions using flow syntheses from 1992-2007 - a Gulf of Mexico study  

NASA Astrophysics Data System (ADS)

We present results from an ensemble of BP oil spill simulations. The oil spill slick is modeled as a buoyant surface plume that is transported by ocean currents modulated, in some experiments, by surface winds. Ocean currents are taken from ECCO2 project (see http://ecco2.org ) observationally constrained state estimates spanning 1992-2007. In this work we (i) explore the role of increased resolution of ocean eddies, (ii) compare inferences from particle based, lagrangian, approaches with eulerian, field based, approaches and (ii) examine the impact of differential response of oil particles and water to normal and extreme, hurricane derived, wind stress. We focus on three main questions. Is the simulated response to an oil spill markedly different for different years, depending on ocean circulation and wind forcing? Does the simulated response depend heavily on resolution and are lagrangian and eulerian estimates comparable? We start from two regional configurations of the MIT General Circulation Model (MITgcm - see http://mitgcm.org ) at 16km and 4km resolutions respectively, both covering the Gulf of Mexico and western North Atlantic regions. The simulations are driven at open boundaries with momentum and hydrographic fields from ECCO2 observationally constrained global circulation estimates. The time dependent surface flow fields from these simulations are used to transport a dye that can optionally decay over time (approximating biological breakdown) and to transport lagrangian particles. Using these experiments we examine the robustness of conclusions regarding the fate of a buoyant slick, injected at a single point. In conclusion we discuss how future drilling operations could use similar approaches to better anticipate outcomes of accidents both in this region and elsewhere.

Tulloch, R.; Hill, C. N.; Jahn, O.

2010-12-01

172

The identification and characterization of two populations of aggregating proteoglycans of high buoyant density isolated from post-natal human articular cartilages of different ages.  

PubMed Central

After chromatography on Sepharose CL-2B under associative conditions, high-buoyant-density human articular-cartilage proteoglycans were analysed biochemically and by radioimmunoassay with monoclonal antibodies to a core-protein-related epitope and to keratan sulphate. An examination of proteoglycans from individuals of different ages revealed the presence at 1 year of mainly a single polydisperse population containing chondroitin sulphate (uronic acid) and keratan sulphate. From 4 years onwards a smaller keratan sulphate-rich and chondroitin sulphate-deficient population appears in increasing amounts until 15 years. At the same time the larger population shows a progressive decrease in size from 1 year onward. By 23 years and after the proportion of keratan sulphate in the larger chondroitin sulphate-rich proteoglycan increases. Both adult proteoglycan populations are shown immunologically to aggregate with hyaluronic acid, with the smaller showing a greater degree of interaction. The larger population is richer in serine and glycine, and the smaller population contains more glutamic acid/glutamine, alanine, phenylalanine, lysine and arginine; its protein content is also higher. Whether the larger post-natal population represents a different gene product from the single polydisperse population found in the human fetus, which has a different amino acid composition, remains to be established. The smaller population, which represents approximately one-third the mass of the larger population in the adult, may represent a degradation product of the larger population, in which the hyaluronic acid-binding region and keratan sulphate-rich region are conserved.

Webber, C; Glant, T T; Roughley, P J; Poole, A R

1987-01-01

173

Small-Dense LDL Cholesterol/Large-Buoyant LDL Cholesterol Ratio as an Excellent Marker for Indicating Lipodystrophy in HIV-Infected Patients.  

PubMed

Objectives: To examine whether the lipid parameters are predicting factors for human immunodeficiency virus (HIV)-associated lipodystrophy. Methods: Whole-body fat compositions of HIV-positive patients receiving stavudine-containing antiretroviral regimens (n = 79) were determined. Lipodystrophy was defined as a ratio of trunk fat mass/lower limb fat mass greater than 2.28. Blood samples were analyzed for total cholesterol (TC), triglycerides, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), small-dense LDL-C (sdLDL-C), apoAI, apoB, lipoprotein(a), and CD4 cell counts. Large-buoyant LDL-C (lbLDL-C) was calculated (LDL-C minus sdLDL-C). Results: Twenty-six patients were classified as having lipodystrophy. The mean values of triglycerides, HDL-C, sdLDL-C, apoB, TC/HDL-C, apolipoprotein (apo) B/apoAI, and sdLDL-C/lbLDL-C showed significant differences between patients with and without lipodystrophy (P < .02). Using logistic regression analysis, sdLDL-C/lbLDL-C was identified as a significant predictor of lipodystrophy (P < .001). At a ratio of 0.554, the odds ratio was 17.8 with a likelihood ratio of 5.5. Conclusions: The sdLDL-C/lbLDL-C ratio is an excellent marker for indicating lipodystrophy in HIV-infected patients. PMID:24045547

Srisawasdi, Pornpen; Suwalak, Tanida; Sukasem, Chonlaphat; Chittamma, Anchalee; Pocathikorn, Anothai; Vanavanan, Somlak; Puangpetch, Apichaya; Santon, Siwalee; Chantratita, Wasun; Kiertiburanakul, Sasisopin; Kroll, Martin H

2013-10-01

174

Microbial Diversity of Hydrothermal Vent Neutrally-Buoyant Plume Particles From 9 North, East Pacific Rise, After a Major Tectonic Event in 2005-2006  

NASA Astrophysics Data System (ADS)

Bacterial communities associated with descending, non-buoyant plume particles were collected in two sediment traps at 9°N on the East Pacific Rise over a 126 day period after a major tectonic event at the mid-oceanic ridge in 2005-2006. The communities from 15 trap samples were compared using Automated Ribosomal Intergenic Spacer Analysis (ARISA) analyzed using Bray-Curtis similarity on Primer6 software. Mean average values for OTUs of the samples and their replicates reveal spatial variation between sampling sites to be less significant than temporal variation: samples from both sites showed at least 50 - 60% similarity to each other, but temporal results suggest a distinctly different microbial community arising at the latest sampling times (i.e. 120-126 days). To draw more absolute measurements of spatial and temporal variation in the microbial communities within plume particles, samples from both vent sites and time regimes were selected for targeted sequencing of the 16S rRNA gene based on the ARISA results. Results from these sequencing efforts will be discussed and put in context with other diversity data from the geochemical endpoints of vent plumes: bottom water ambient seawater and hydrothermal fluids. In the future, we will use 454/V6-TAG sequencing to complement ARISA fingerprints and targeted sequencing and to assess total community diversity. These data will be analyzed in concert with geochemical and mineralogical data to reveal trends in biogeochemical processes in hydrothermal plumes and their correlation to microbial communities.

Pyenson, B. C.; Sylvan, J. B.; Toner, B. M.; Rouxel, O. J.; German, C. R.; Edwards, K. J.

2008-12-01

175

THE USE OF AN ETHIDIUM ANALOGUE IN THE DYE-BUOYANT DENSITY PROCEDURE FOR THE ISOLATION OF CLOSED CIRCULAR DNA: THE VARIATION OF THE SUPERHELIX DENSITY OF MITOCHONDRIAL DNA*  

PubMed Central

The separation between open and closed circular DNA in buoyant CsCl gradients containing intercalating dyes depends on the superhelix density of the closed form. These separations are about 1.8 times larger with propidium iodide than with ethidium bromide. The superhelix densities of mitochondrial DNA from HeLa cells and Lytechinus pictus eggs appear to be about two thirds that of mitochondrial DNA from rat and rabbit liver. Images

Hudson, Bruce; Upholt, William B.; Devinny, Joseph; Vinograd, Jerome

1969-01-01

176

Experimental study of reaction between perovskite and molten iron to 146 GPa and implications for chemically distinct buoyant layer at the top of the core  

NASA Astrophysics Data System (ADS)

Partitioning of oxygen and silicon between molten iron and (Mg,Fe)SiO3 perovskite was investigated by a combination of laser-heated diamond-anvil cell (LHDAC) and analytical transmission electron microscope (TEM) to 146 GPa and 3,500 K. The chemical compositions of co-existing quenched molten iron and perovskite were determined quantitatively with energy-dispersive X-ray spectrometry (EDS) and electron energy loss spectroscopy (EELS). The results demonstrate that the quenched liquid iron in contact with perovskite contained substantial amounts of oxygen and silicon at such high pressure and temperature ( P-T). The chemical equilibrium between perovskite, ferropericlase, and molten iron at the P-T conditions of the core-mantle boundary (CMB) was calculated in Mg-Fe-Si-O system from these experimental results and previous data on partitioning of oxygen between molten iron and ferropericlase. We found that molten iron should include oxygen and silicon more than required to account for the core density deficit (<10%) when co-existing with both perovskite and ferropericlase at the CMB. This suggests that the very bottom of the mantle may consist of either one of perovskite or ferropericlase. Alternatively, it is also possible that the bulk outer core liquid is not in direct contact with the mantle. Seismological observations of a small P-wave velocity reduction in the topmost core suggest the presence of chemically-distinct buoyant liquid layer. Such layer physically separates the mantle from the bulk outer core liquid, hindering the chemical reaction between them.

Ozawa, Haruka; Hirose, Kei; Mitome, Masanori; Bando, Yoshio; Sata, Nagayoshi; Ohishi, Yasuo

2009-06-01

177

The initial evolution of a buoyant plume  

Microsoft Academic Search

The dynamics of river plumes in a stratified non-tidal sea is considered on the basis of a linear analytical theory and simulations with a numerical primitive equations model based on the GFDL-general circulation model with free surface. The response to an onset of river runoff consists basically of two parts: The formation of a freshwater bulge right in front of

W. Fennel; A. Mutzke

1997-01-01

178

Buoyant Test Vehicle Polymer Ejection Nose Assembly.  

National Technical Information Service (NTIS)

An underwater vehicle has a generally cylindrically portion with boundary layer polymer fluid storage and a pressurizing source provided therein, and a nose portion secured to the cylindrical portion and capable of being reconfigured for ejecting the poly...

W. H. Nedderman R. Meunier

1996-01-01

179

Buoyant Bubbles and Cavities in Galaxy Clusters  

NASA Astrophysics Data System (ADS)

The latest generation of X-ray observatories has revealed a rich array of complex structures in galaxy intracluster media (ICMs). Remarkable among these discoveries is the common existence of X-ray ICM 'cavities' filled with radio synchrotron-emitting relativistic plasma. The cavities, which are generally paired and often multiple, range in size from a few kpc up to hundreds of kpc, are evidently the depositories of AGN jets. The energy contents of these 'bubbles' range above 1060 erg, making them potentially important players in ICM thermodynamics. They also carry potentially important cosmic ray and magnetic field constituents. The important problems of understanding their stability and dynamics, including how and where they share their contents are very active research topics that I will address in this talk. This work is supported by the US National Science Foundation and the University of Minnesota Supercomputing Institute.

Jones, Thomas

180

INSTITUTIONAL PROFILE: Scientific Ballooning's Buoyant Mood.  

PubMed

For the past decade, scientific ballooning has been in a steady decline, but a comeback is now in the works here at the National Scientific Balloon Facility (NSBF). This year's Decadal Review of astronomy has for the first time recommended that NASA increase support for this oft-neglected stepchild of the space program. And in June, the NSBF completed a milestone test flight of its Ultra-Long Duration Balloon, a sealed balloon capable of carrying several tons to 37,000 meters for 100 days that could make balloons competitive with satellites for doing research. PMID:17832061

Sincell, M

2000-07-28

181

Properties of Buoyant Materials and Structures.  

National Technical Information Service (NTIS)

This report is directed at furnishing information on the various kinds of materials which can be employed for the construction of flotation devices, a description of typical float structures comprised of the materials listed and generalized mathematical r...

J. Irgon C. Juhasz D. Z. Lippmann M. Armstrong M. P. Stoltenberg

1964-01-01

182

Antigen-initiated B-lymphocyte differentiation. VIII. Sedimentation velocity and buoyant density characterization of virgin antibody- forming cell progenitors in the adoptive immune response of unprimed CBA mice to 4-hydroxy-3-iodo-5-nitrophenylacetic acid-polymerized bacterial flagellin antigen  

PubMed Central

The characteristics of antibody-forming cell (AFC) progenitors lacking previous contact with specific antigen (virgin AFC progenitors) has been studied using sedimentation velocity and buoyant density separation for the investigation of physically distinct B-cell subpopulations. Functional characterization of isolated subsets was made using a quantitative adoptive immune assay for the IgM AFC progenitors responding to the antigen 4-hydroxy-3-iodo-5- nitrophenylacetic acid conjugated polymerized bacterial flagellin. Extensive heterogeneity is present among B lymphocytes, only some subpopulations of which exhibit AFC progenitor function. In the spleen of adult conventional CBA mice, atypically fast sedimenting cells of low buoyant density are active, while typical small B lymphocytes do not appear to be progenitors of IgM AFC. Spleen of adult specific pathogen-free (SPF), germfree, and athymic nude mice give similar results, although a minor population of typical slowly sedimenting dense cells are active in the latter two sources. Adult conventional bone marrow cells are as physically and functionally heterogeneous as splenic B cells, and although a significant proportion of AFC progenitor activity is found among dense, slowly sedimenting cells, most of the activity is among low density, faster sedimenting cells. In contrast to this situation in adult animals, where most of the unprimed AFC progenitors are large, atypical B cells, the spleens of neonatal mice provide a site where virgin AFC progenitors with the physical properties of typical small B lymphocytes are found. While being present in conventional and SPF neonatal spleens, these virgin cells are predominant in 7-day-old germfree mouse spleen. These findings suggest that the newborn virgin B cell is a typical small lymphocyte. However, few cells of this type are found in the adult animal. The unprimed AFC-progenitor population in the adult consists of large, fast sedimenting, low buoyant density, adherent cells, the physical properties of which are characteristic of activated B lymphocytes. It is suggested that these atypical cells are derived from the small newborn virgin B cell by the nonspecific effects of environmental antigenic stimuli.

1976-01-01

183

A numerical study of interacting buoyant cooling-tower plumes  

Microsoft Academic Search

The compact design of mechanical cooling towers necessitates that the plumes are issued into the cross-wind in close proximity. An improved understanding of the interaction of adjacent plumes is therefore required for better design of such cooling towers, which may lead to a reduction in their environmental impact. This paper presents the results of a numerical investigation into the interaction

R. B. Bornoff; M. R. Mokhtarzadeh-Dehghan

2001-01-01

184

Buoyant Outflows in the Presence of Complex Topography.  

National Technical Information Service (NTIS)

The overarching goal is to elucidate the complex dynamics of outflows connecting basins through straits. The long term scientific goals are to (a) understand the physical mechanisms that control the exchange between two marginal seas with substantially di...

V. H. Kourafalou

2009-01-01

185

Solutions for turbulent buoyant plumes rising from circular sources  

NASA Astrophysics Data System (ADS)

Analytical solutions are developed for turbulent plumes rising from circular sources of positive buoyancy in a quiescent environment of uniform density. From governing equations written in a form which encompasses both the Boussinesq and non-Boussinesq cases, we derive analytical expressions for all plume variables (radius, velocity, and density deficit) in terms of a single quantity ?, called the plume function. For given source conditions, we then show that ? (and, subsequently, all plume variables) can be evaluated at any height from two integral functions which are defined for lazy and forced plumes. For a practical use, these integral functions are given in tables. Moreover, exact values and locations of the maximum velocity and the plume neck are determined.

Michaux, G.; Vauquelin, O.

2008-06-01

186

Buoyant plane plumes from heated horizontal confined wires and cylinders  

Microsoft Academic Search

Two-dimensional computations are reported for time-dependent laminar buoyancy-induced flows above a horizontal heated source\\u000a immersed in an air-filled vessel. Two kinds of heated source were considered: a line heat source, modelled as a heat source\\u000a term in the energy equation, and a heat-flux cylinder of small diameter. First, comparisons are presented for the results\\u000a obtained for these two heated sources.

Guy Lauriat; Gilles Desrayaud

1994-01-01

187

Numerical prediction of buoyant air flow in livestock buildings.  

National Technical Information Service (NTIS)

In modern livestock buildings air distribution and air quality are important parameters to animal welfare and to the health of full-time employees in animal production. Traditional methods for calculating air distribution in farm buildings are mainly base...

K. Svidt

1993-01-01

188

Time-dependent buoyant puff model for explosive sources  

SciTech Connect

This paper presents a new model for explosive puff rise histories that is derived from the strong conservative form of the partial differential equations of mass, momenta, and total energy that are integrated over space to yield a coupled system of time dependent nonlinear ordinary differential equations (ODEs). By allowing the dimensions of the puff to evolve laterally and horizontally, the initial rising spherical shaped puff evolves into a rising ellipsoidal shaped mushroom cloud. This model treats the turbulence that is generated by the puff itself and the ambient atmospheric turbulence as separate mechanisms in determining the puff history. The puff rise history was found to depend not only upon the mass and initial temperature of the explosion, but also upon the local stability conditions of the ambient atmosphere through which the puff rises. This model was calibrated by comparison with the Roller Coaster experiments, ranging from unstable to very stable atmospheric conditions; the agreement of the model history curves with these experimental curves was within 10%.

Kansa, E.J.

1997-10-01

189

46 CFR 160.010-3 - Inflatable buoyant apparatus.  

Code of Federal Regulations, 2012 CFR

...IMO Revised recommendation on testing (incorporated by reference...IMO Revised recommendation on testing and § 160.151-27(a...IMO Revised recommendation on testing and § 160.151-27(a) must...or multi-tone whistle of corrosion-resistant...

2012-10-01

190

Morphology of flows and buoyant bubbles in the Virgo cluster  

NASA Astrophysics Data System (ADS)

There is growing evidence that the active galactic nuclei (AGN) associated with the central elliptical galaxy in clusters of galaxies are playing an important role in the evolution of the intracluster medium (ICM) and clusters themselves. We use high-resolution three-dimensional simulations to study the interaction of the cavities created by AGN outflows (bubbles) with the ambient ICM. The gravitational potential of the cluster is modelled using the observed temperature and density profiles of the Virgo cluster. We demonstrate the importance of the hydrodynamical Kutta-Zhukovsky forces associated with the vortex ring structure of the bubbles, and discuss possible effects of diffusive processes on their evolution.

Pavlovski, Georgi; Kaiser, Christian R.; Pope, Edward C. D.; Fangohr, Hans

2008-03-01

191

Buoyant bubbles in a cooling intracluster medium. I. Hydrodynamic bubbles  

NASA Astrophysics Data System (ADS)

Aims:Over the past several years, numerous examples of X-ray cavities coincident with radio sources have been observed in so-called “cool core” clusters of galaxies. Motivated by these observations, we explore the evolution and the effect of cavities on a cooling intracluster medium (ICM) numerically, adding relevant physics step by step. Methods: In this paper we present a first set of hydrodynamical, high resolution (10243 effective grid elements), three-dimensional simulations, together with two-dimensional test cases. The simulations follow the evolution of radio cavities, modeled as bubbles filled by relativistic plasma, in the cluster atmosphere, while the ICM is subject to cooling. Results: We find that the bubble rise retards the development of a cooling flow by inducing motions in the ICM, which repeatedly displace the material in the core. Even bubbles initially set significantly far from the cluster center affect the cooling flow, although much later than the beginning of the simulation. The effect is, however, modest: the cooling time is increased by at most only 25%. As expected, the overall evolution of pure hydrodynamic bubbles is at odds with observations, showing that some additional physics has to be considered to match the data.

Gardini, A.

2007-03-01

192

46 CFR 160.010-3 - Inflatable buoyant apparatus.  

Code of Federal Regulations, 2011 CFR

...completely drain the floor of water when the device is fully loaded, and must prevent water from flowing back onto the...One flashlight with spare batteries as described in § 160.151-21...automatically upon reaching the water. (4) An...

2011-10-01

193

Meeting Minutes - Provenge  

Center for Biologics Evaluation and Research (CBER)

Text VersionPage 1. Minutes May 22, 2007 Dendreon STN 125197/0 Dr.Goodman, Witten: FDA Gold, Urdal: Dendreon A meeting was ... More results from www.fda.gov/downloads/biologicsbloodvaccines/cellulargenetherapyproducts

194

Telecon - Provenge, May 9. 2007  

Center for Biologics Evaluation and Research (CBER)

... Telecon - Provenge, May 9. 2007. Telecon May 9, 2007. Participants FDA: Keith Wonnacott Dendreon: Elizabeth Smith. Summary ... More results from www.fda.gov/biologicsbloodvaccines/cellulargenetherapyproducts/approvedproducts

195

Effects of the Boussinesq Approximation on the Results of Strongly-Buoyant Plume Calculations  

Microsoft Academic Search

Nearly all mathematical models which are commonly used to predict the dispersion of chimney gases in the atmosphere or heated water discharges in the aquatic environment employ the so-called Boussinesq approximation. It is part of this approximation that density variations appear solely in the buoyancy term of the momentum equation and are neglected in all other terms.The exact limits of

M. Schatzmann; A. J. Policastro

1984-01-01

196

Power-law decaying oscillations of neutrally buoyant spheres in continuously stratified fluid  

NASA Astrophysics Data System (ADS)

The free sinking motion of small spheres is experimentally investigated in a laboratory tank filled up with continuously stratified salt solutions. Special attention is paid to the late stage oscillations around the gravitational equilibrium level. Such motion is generated by slowly decaying weak internal waves originating from the interaction of the solid sphere with the surrounding fluid. The temporal decay of oscillation amplitudes and velocities can be best described by a power law of exponent value close to -3/2. Up to our best knowledge, none of the existing theories can predict a similar algebraic decay.

Biró, István; Gábor Szabó, K.; Gyüre, Balázs; Jánosi, Imre M.; Tél, Tamás

2008-05-01

197

Influence of a buoyant river plume on phytoplankton nutrient dynamics: What controls standing stocks and productivity?  

NASA Astrophysics Data System (ADS)

The influence of the Columbia River plume on phytoplankton rates and biomass accumulation was examined using multiday deckboard incubations as part of the coastal ocean processes River Influences on Shelf Ecosystems field program in August 2005. At a set of five stations encompassing the near-field plume (three stations) on the Oregon and Washington coasts, treatments consisting of control, added nitrate, and added nitrate with 0.45 ?m filtered plume water were used to assess the phytoplankton community response to macronutrients and micronutrients. For a subset of these stations, nutrient (nitrate, ammonium, and ammonium inhibition of nitrate) kinetics were obtained, as well as carbon-based estimates of productivity. For all experiments, nitrogen (nitrate) was clearly controlling both biomass accumulation and growth rates. Despite the apparent poleward trend toward increasing biomass in this region, there were no obvious differences in phytoplankton physiological capacity, nor were there any symptoms of iron limitation in the short term. We conclude that phytoplankton in this region are predominantly nitrogen limited but that upon release from this limiting factor, phosphorous and/or silicic acid (in waters not influenced by the Columbia River plume) would quickly become limiting. Evidence suggests that the mesoscale differences in phytoplankton biomass between the Oregon and Washington coasts result from a combination of enhanced grazing downstream and the physically retentive and dispersive effects of the plume itself.

Kudela, Raphael M.; Peterson, Tawnya D.

2009-02-01

198

Ascent and emplacement of buoyant magma bodies in brittle-ductile upper crust  

Microsoft Academic Search

The emplacement of silicic magma bodies in the upper crust may be controlled by density (such that there is no buoyancy to drive further ascent) or temperature (such that surrounding rocks are too cold to deform significantly over geological timescales). Evidence for the latter control is provided by negative gravity anomalies over many granitic plutons. Conditions of diapir ascent and

Evgene Burov; Claude Jaupart; Laurent Guillou-Frottier

2003-01-01

199

Modern production risers. Part 11. The buoyant tower - new deepwater drilling and production concept  

Microsoft Academic Search

Two related projects, the Deep Sea Drilling Project and the International Phase of Ocean Drilling, showed that sedimentary accumulations along the continental margins and the small ocean basins had high prospects of having significant oil and gas reservoirs. Safe, reliable, and economic methods for drilling and extracting the oil and gas need to be developed to address the large number

R. Cowan; E. E. Horton

1983-01-01

200

NMR imaging and hydrodynamic analysis of neutrally buoyant non-Newtonian slurry flows  

NASA Astrophysics Data System (ADS)

The flow of solids loaded suspension in cylindrical pipes has been the object of intense experimental and theoretical investigations in recent years. These types of flows are of great interest in chemical engineering because of their important use in many industrial manufacturing processes. Such flows are for example encountered in the manufacture of solid-rocket propellants, advanced ceramics, reinforced polymer composites, in heterogeneous catalytic reactors, and in the pipeline transport of liquid-solids suspensions. In most cases, the suspension microstructure and the degree of solids dispersion greatly affect the final performance of the manufactured product. For example, solid propellant pellets need to be extremely-well dispersed in gel matrices for use as rocket engine solid fuels. The homogeneity of pellet dispersion is critical to allow good uniformity of the burn rate, which in turn affects the final mechanical performance of the engine. Today's manufacturing of such fuels uses continuous flow processes rather than batch processes. Unfortunately, the hydrodynamics of such flow processes is poorly understood and is difficult to assess because it requires the simultaneous measurements of liquid/solids phase velocities and volume fractions. Due to the recent development in pulsed Fourier Transform NMR imaging, NMR imaging is now becoming a powerful technique for the non intrusive investigation of multi-phase flows. This paper reports and exposes a state-of-the-art experimental and theoretical methodology that can be used to study such flows. The hydrodynamic model developed for this study is a two-phase flow shear thinning model with standard constitutive fluid/solids interphase drag and solids compaction stresses. this model shows good agreement with experimental data and the limitations of this model are discussed.

Bouillard, J. X.; Sinton, S. W.

201

46 CFR 131.865 - Inflatable liferafts and inflatable buoyant apparatus.  

Code of Federal Regulations, 2012 CFR

...CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS Markings for Fire Equipment and Emergency Equipment § 131.865 Inflatable...at least 38 millimeters (1-1/2 inches) high and in a color contrasting to that of the raft or apparatus. Each raft or...

2012-10-01

202

Evidence that platelet buoyant density, but not size, correlates with platelet age in man  

SciTech Connect

Following infusion of 51Cr-labeled autologous platelets into normal subjects, high-density (HD) and low-density (LD) platelet cohorts were isolated by prolonged centrifugation in isosmotic arabino-galactan (Stractan). Specific radio-activity of LD platelets declined rapidly post-infusion (T1/2 . 1.5 days), but specific radioactivity of HD platelets remained constant or increased over a 3--4-day period and gradually declined for 6--7 days thereafter. These differences were exaggerated when platelet cohorts enriched in LD or HD cells by slow centrifugation in high-density albumin were labeled and transfused. Mean survival of a platelet cohort enriched with HD cells was significantly (P less than 0.02) shorter (7.73 days) than that of a cohort enriched with LD cells (9.33) days). In normal subjects treated with aspirin, capacity for thromboxane synthesis was regained more rapidly (P less than 0.05) in LD than in HD platelets. HD and LD platelets differed only slightly in mean volume (HD platelets . 7.57 mu3, LD platelets . 6.87 mu3, 0.05 less than P less than 0.01). We believe the most logical interpretation of these findings is that under normal conditions in man, newly formed platelets are less dense on the average than total platelets and become more dense as they age in the circulation. Thus, specific radioactivity of LD platelets declines rapidly as these platelets move into a more dense compartment and are replaced by newly formed, unlabelled cells; specific radioactivity of HD platelets remains constant or increases as labelled platelets enter this compartment in numbers equal to or greater than the number leaving it at the end of their life span. The similarity in mean volumes of LD and HD platelets suggests that platelet size is unrelated to platelet age under normal conditions.

Mezzano, D.; Hwang, K.; Catalano, P.; Aster, R.H.

1981-01-01

203

Numerical study of three-dimensional buoyant convection in rectangular enclosures  

SciTech Connect

The problem of thermal interaction of melted fuel material (corium) within the reactor vessel is of interest for many reasons in studies of accidents with core melt in nuclear power plants with light water reactors. One of them is an estimation of the lifetime of the reactor vessel and the character of the vessel failure for the existing types of reactors, depending on the main parameters of interaction: residual heat generation, thermal and mechanical properties of materials, and cooling conditions. The second reason is a feasibility study of long-term confinement of fuel fragments for promising reactors with relatively low electric power (400 to 600 MW). We focus on the final state of the core, in which most of the corium material is a homogenous melt, located at the bottom of the reactor vessel.

Bolshov, L.A.; Chudanov, V.V.; Pavlov, A.N.; Pervichko, V.A.; Strizhov, V.V.; Vabishchevich, P.N. [Russian Academy of Sciences, Moscow (Russian Federation)

1995-12-31

204

Interferometric measurement technique for the temperature field of axisymmetric buoyant phenomena.  

PubMed

A method is described to measure the temperature field of axisymmetric laminar thermals, plumes, and starting plume caps in a liquid. The sample liquid is placed in a Mach-Zender interferometer, and an infinite-fringe interferogram is recorded on photographic film. By comparison with a bar pattern interferogram, the fringe shift field was measured to an accuracy of +/-0.02. The Bockasten series approximation of the Abel transformation was applied to the fringe shift field to obtain the radial refractive index variation field, which in turn could be related to the temperature variation field through an empirical relationship. Temperature accuracies in the range of +/-0.05 to +/-0.5 degrees C were obtained. The radial temperature profile of the plume was found to be monotonically decreasing, while the cap had a local maximum offset from the axis. PMID:20203867

Boxman, R L; Shlien, D J

1978-09-01

205

Interferometric measurement technique for the temperature field of axisymmetric buoyant phenomena  

Microsoft Academic Search

A method is described to measure the temperature field of axisymmetric laminar thermals, plumes, and starting plume caps in a liquid. The sample liquid is placed in a Mach-Zender interferometer, and an infinite-fringe interferogram is recorded on photographic film. By comparison with a bar pattern interferogram, the fringe shift field was measured to an accuracy of + or - 0.02.

R. L. Boxman; D. J. Shlien

1978-01-01

206

Turbulent buoyant convection from a maintained source of buoyancy in a narrow vertical tank  

NASA Astrophysics Data System (ADS)

We describe new experiments to examine the buoyancy-induced mixing which results from the injection of a small constant volume flux of fluid of density ?s at the top of a long narrow vertical tank with square cross-section that is filled with fluid of density ?0

van Sommeren, Daan D. J. A.; Caulfield, C. P.; Woods, Andrew W.

2011-11-01

207

The effect of wind mixing on the vertical distribution of buoyant plastic debris  

NASA Astrophysics Data System (ADS)

Micro-plastic marine debris is widely distributed in vast regions of the subtropical gyres and has emerged as a major open ocean pollutant. The fate and transport of plastic marine debris is governed by poorly understood geophysical processes, such as ocean mixing within the surface boundary layer. Based on profile observations and a one-dimensional column model, we demonstrate that plastic debris is vertically distributed within the upper water column due to wind-driven mixing. These results suggest that total oceanic plastics concentrations are significantly underestimated by traditional surface measurements, requiring a reinterpretation of existing plastic marine debris data sets. A geophysical approach must be taken in order to properly quantify and manage this form of marine pollution.

Kukulka, T.; Proskurowski, G.; Morét-Ferguson, S.; Meyer, D. W.; Law, K. L.

2012-04-01

208

Numerical simulations of a buoyant autocatalytic reaction front in tilted Hele-Shaw cells.  

PubMed

We present a numerical analysis of solutal buoyancy effects on the shape and the velocity of autocatalytic reaction fronts, propagating in thin tilted rectangular channels. We use two-dimensional (2D) lattice Bathnagar-Gross-Krook (BGK) numerical simulations of gap-averaged equations for the flow and the concentration, namely a Stokes-Darcy equation coupled with an advection-diffusion-reaction equation. We do observe stationary-shaped fronts, spanning the width of the cell and propagating along the cell axis. We show that the model accounts rather well for experiments we performed using an Iodate Arsenous Acid reaction propagating in tilted Hele-Shaw cells, hence validating our 2D modelization of a three-dimensional problem. This modelization is also able to account for results found for another chemical reaction (chlorite tetrathionate) in a horizontal cell. In particular, we show that the shape and the traveling velocity of such fronts are linked with an eikonal equation. Moreover, we show that the front velocity varies nonmonotonically with the tilt of the cell, and nonlinearly with the width of the cell. PMID:20866526

Jarrige, N; Bou Malham, I; Martin, J; Rakotomalala, N; Salin, D; Talon, L

2010-06-22

209

Model-Based Inquiry: A Buoyant Force Module for High School Physics Classes  

ERIC Educational Resources Information Center

|Model-Based Inquiry (MBI) is an emergent instructional strategy that is gaining acceptance among science educators. This approach to learning realistically mirrors the work of scientists, who develop and test hypotheses to construct more sophisticated understandings of the natural world. This article details how the authors collaboratively taught…

Neilson, Drew; Campbell, Todd; Allred, Benjamin

2010-01-01

210

Numerical computation of buoyant airflows confined to attic spaces under opposing hot and cold wall conditions  

Microsoft Academic Search

The present paper addresses laminar natural convection of air confined to an isosceles triangular cavity representative of conventional attic spaces in houses and buildings with pitched roofs and horizontal suspended ceilings. Detailed experimental data in terms of velocities, temperatures and wall heat fluxes has become available for attic spaces under summer and winter conditions some time ago. However, the comparison

El Hassan Ridouane; Antonio Campo; Matthew McGarry

2005-01-01

211

Visualization of flow in a cyclone separator by using neutrally buoyant helium-filled 'soap' bubbles  

NASA Astrophysics Data System (ADS)

The behavior of the flow and secondary flow effects in different regions of a cyclone separator can be identified by means of the helium-bubble technique. Streak lines in the boundary layer, the main flow, and the regions of entry and exit demonstrate the flow effects which have negative effects on pressure and separation efficiency. The data from the visualization can be utilized in the optimization of cyclone separators.

Peters, F.; Schulz, S.; Kiske, S.

212

Melting-driven evolution of an ice-shelf coupled to a buoyant meltwater plume  

NASA Astrophysics Data System (ADS)

Melting at the base of ice shelves can impact ice-sheet flow and hence have consequences for sea-level rise. Recent measurements have revealed significant heterogeneities in ice-shelf thickness, including channels and undulations in the ice-shelf base. However, the precise conditions for genesis remain unclear. The buoyancy-driven flow of meltwater under an ice shelf is sensitive to ice-shelf geometry, with faster flow under steeper basal slopes providing a feedback that increases melting rates. To build insight into the potential for melting-driven instability, I consider the simplified setting of a two-dimensional stationary ice shelf melting into a warmer ocean. A theoretical model is developed to describe the coupling of a meltwater plume to an evolving ice-shelf geometry. When there is negligible subglacial discharge, the subsequent weak-flow regime near to the grounding line results in a planar ice-water interface being neutrally stable to small perturbations. Hence, the amplitude of perturbations to the basal slope neither grows, nor decays. In the absence of ice-deformation, the nonlinear evolution of melting results in cusp-like features in the ice-shelf base.

Wells, Andrew J.

2013-04-01

213

Evaluation of the Split-H approach to modeling non-buoyant releases from vent stacks  

SciTech Connect

Position C.2.b of Regulatory Guide 1.111 describes an approach to modeling the diffusion of effluents from roof top vents and short stacks using an elevated plume model under some conditions and using a ground-level source building wake model under other conditions. The approach is sometimes called a Split-H model. This report presents the results of an evaluation of the technical basis for and utility of the concept behind the Split-H model, outlines the devlopment of an upgraded model with those estimated using the Regulatory Guide Split-H model and a ground-level building wake model, and discusses alternatives to the Regulatory Guide position that the NRC may wish to consider. Concentration comparisons are made using model results for meteorological data from 18 nuclear power plant sites.

Ramsdell, J.V.

1983-04-01

214

Impact of co-flow air on buoyant diffusion flames flicker  

Microsoft Academic Search

This paper describes experimental investigation of co-flow air velocity effects on the flickering behaviour of laminar non-lifted methane diffusion flames. Chemiluminescence, high-speed photography, schlieren and Particle Imaging Velocimetry (PIV), have been used to study the changes in the flame\\/vortex interactions as well as the flame flickering frequency and magnitude by the co-flow air. Four cases of methane flow rates at

H. Gohari Darabkhani; Q. Wang; L. Chen; Y. Zhang

2011-01-01

215

The 'employability gap': long-term unemployment and barriers to work in buoyant labour markets  

Microsoft Academic Search

We analyse the main barriers limiting the employability of long-term unemployed job seekers within a local labour market characterised by generally high levels of demand. We use four key elements of employability (employability assets, the deployment of assets, the presentation of assets, and context) as an analytical framework in order to analyse the manner in which job seekers' personal characteristics,

Ronald W McQuaid; Colin Lindsay

2002-01-01

216

Model-Based Inquiry: A Buoyant Force Module for High School Physics Classes  

ERIC Educational Resources Information Center

Model-Based Inquiry (MBI) is an emergent instructional strategy that is gaining acceptance among science educators. This approach to learning realistically mirrors the work of scientists, who develop and test hypotheses to construct more sophisticated understandings of the natural world. This article details how the authors collaboratively taught…

Neilson, Drew; Campbell, Todd; Allred, Benjamin

2010-01-01

217

ESTIMATING SURFACE CONCENTRATIONS FROM AN ELEVATED, BUOYANT PLUME IN A LIMITED-MIXED CONVECTIVE BOUNDARY LAYER  

EPA Science Inventory

In the past decade, recent advances have suggested that convective scaling can be used to parameterize diffusion from a plume in the convective boundary layer (CBL). New methods such as convective scaling need to be explored because the traditionally used Gaussian plume model doe...

218

Dynamics of turbid buoyant plumes and the feedbacks on near-shore biogeochemistry and physics  

Microsoft Academic Search

The near-shore waters of the New York\\/New Jersey Bight in April 2005 exhibited distinct regions of turbid water with clearly differing optical properties associated with the Hudson River plume. We examined the effect of variable light attenuation on the hydrodynamics and ecological response of the Hudson River plume and its environs using field observations and a 3-dimensional bio-physical model. Important

Bronwyn Cahill; Oscar Schofield; Robert Chant; John Wilkin; Eli Hunter; Scott Glenn; Paul Bissett

2008-01-01

219

Simulation of strong turbulent buoyant flow in a vented complex enclosure  

Microsoft Academic Search

A three-dimensional field model for turbulent flow in an arbitrary compartment, taking into account strong buoyancy, full compressibility, turbulence, surface-surface radiation exchange, and wall heat losses is utilized to simulate a full-scale fire test in a fire room with open doorways located in a decommissioned nuclear reactor containment vessel in Germany. Results show that reasonable agreement in the numerical and

K. T. Yang; Q. Xia; V. F. Nicolette

1994-01-01

220

Simulation of strong turbulent buoyant flow in a vented complex enclosure  

NASA Astrophysics Data System (ADS)

A three-dimensional field model for turbulent flow in an arbitrary compartment, taking into account strong buoyancy, full compressibility, turbulence, surface-surface radiation exchange, and wall heat losses is utilized to simulate a full-scale fire test in a fire room with open doorways located in a decommissioned nuclear reactor containment vessel in Germany. Results show that reasonable agreement in the numerical and test data in the unsteady temperature field at three locations inside the fire room was obtained, even though the numerical simulation underestimated the doorway instantaneous exit velocities by as much as 40%. The discrepancies are discussed in terms of both test uncertainties and adequacy of the physical submodels utilized in the field model.

Yang, K. T.; Xia, Q.; Nicolette, V. F.

1994-08-01

221

Approximate Value of Buoyant Force: A Water-Filled Balloon Demonstration  

NASA Astrophysics Data System (ADS)

Floating and sinking might be common phenomena, encountered on a daily basis, but still represent conceptually complex scientific topics. Research has shown that most students have certain experiences and their own ``theories'' that explain why objects sink or float. Unfortunately, many of these ``theories'' are either misconceptions or are valid only under specific circumstances, lacking the generality of proper scientific explanations.1 Complete understanding of fundamental reasons behind objects' sinking or floating requires complex knowledge, including the analysis of the relationship between buoyancy and the force of gravity.

Radovanovic, Jelena; Slisko, Josip

2012-10-01

222

Lagrangian simulation of the unsteady near field dynamics of planar buoyant plumes  

Microsoft Academic Search

The unsteady dynamics of planar plumes is investigated numerically with particular emphasis on the pulsating instability characterizing the source (nozzle) near field. This instability manifests itself as the periodic shedding of vortical structures from the nozzle. The Lagrangian Transport Element Method is used to provide high resolution two-dimensional simulations of the unaveraged variable density flow. Comparison with experimental results verifies

M. C. Soteriou; Y. Dong; B. M. Cetegen

2002-01-01

223

Hurst-Kolmogorov dynamics applied to temperature field of horizontal turbulent buoyant jets  

NASA Astrophysics Data System (ADS)

Two-dimensional (2D) spatial temperature records obtained from tracer concentration measurements on the plane of symmetry of heated horizontal jets is statistically analyzed using Hurst-Kolmogorov (HK) dynamics. A 2D stochastic simulation, direct extension of the 1D simple scaling process (fractional Gaussian noise), is used to generate the long-term spatial persistence (slowly decaying autocorrelation over scale) of the observed time-series. Moreover, the differences between 1D and 2D (generating temperature time series at a point and on the axis of maximum time-averaged temperature, respectively) scaling processes are also being investigated.

Dimitriadis, Panayiotis; Papanicolaou, Panos

2010-05-01

224

Buoyant convection driven by an encapsuled spinning disk with axial suction  

NASA Astrophysics Data System (ADS)

The Czochralski growth of crystals from a melt is presently analyzed in light of a model for the flow and thermal structures of a viscous fluid confined in a vertically-mounted cylindrical container; the fidelity of this model to the crystal growth process is enhanced through the imposition of an axial suction through the rotating disk and a concomitant radial inflow through the sidewall. Attention is given to the effects of suction in a finite configuration, as well as those of fluid-stratification, as revealed in numerical solutions to the axisymmetric Navier-Stokes equations with the Boussinesq assumption. Comprehensive flow details are obtained; the principal balance in the interior core of a stratified flow is characterized by a relationship between the radial temperature gradient and the vertical shear in the azimuthal flow. Convective heat transfer associated with the meridional fluid transport is dominant in the main body of the flowfield.

Hyun, Jae Min; Kim, Jae Won

1989-04-01

225

A PDF DISPERSION MODEL FOR BUOYANT PLUMES IN THE CONVECTIVE BOUNDARY LAYER (R823419)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

226

NMR imaging and hydrodynamic analysis of neutrally buoyant non-Newtonian slurry flows  

SciTech Connect

The flow of solids loaded suspension in cylindrical pipes has been the object of intense experimental and theoretical investigations in recent years. These types of flows are of great interest in chemical engineering because of their important use in many industrial manufacturing processes. Such flows are for example encountered in the manufacture of solid-rocket propellants, advanced ceramics, reinforced polymer composites, in heterogenous catalytic reactors, and in the pipeline transport of liquid-solids suspensions. In most cases, the suspension microstructure and the degree of solids dispersion greatly affect the final performance of the manufactured product. For example, solid propellant pellets need to be extremely-well dispersed in gel matrices for use as rocket engine solid fuels. The homogeneity of pellet dispersion is critical to allow good uniformity of the burn rate, which in turn affects the final mechanical performance of the engine. Today`s manufacturing of such fuels uses continuous flow processes rather than batch processes. Unfortunately, the hydrodynamics of such flow processes is poorly understood and is difficult to assess because it requires the simultaneous measurements of liquid/solids phase velocities and volume fractions. Due to the recent development in pulsed Fourier Transform NMR imaging, NMR imaging is now becoming a powerful technique for the non intrusive investigation of multi-phase flows. This paper reports and exposes a state-of-the-art experimental and theoretical methodology that can be used to study such flows. The hydrodynamic model developed for this study is a two-phase flow shear thinning model with standard constitutive fluid/solids interphase drag and solids compaction stresses. this model shows good agreement with experimental data and the limitations of this model are discussed.

Bouillard, J.X. [Argonne National Lab., IL (United States); Sinton, S.W. [Lockheed Missiles and Space Co., Palo Alto, CA (United States). Research Lab.

1995-02-01

227

Buoyant Turbulent Jets with Off-Source Heating. Part I: ILES Simulations  

NASA Astrophysics Data System (ADS)

Bhat and Narasimha (JFM 1996) presented an investigation of a novel laboratory experiment analogous to latent heat release during cloud formation. An acidic jet was injected into a deionized ambient, and electrodes were used to selectively heat the conducting jet fluid. We use high-resolution three-dimensional implicit LES simulations to investigate the experiment numerically. The ILES approach uses non-oscillatory finite-volume schemes to capture the inviscid cascade of kinetic energy through the inertial range, while the inherent numerical dissipation acts as an implicit sub-grid model. We first consider the implications of using the ILES approach for turbulent jets and plumes, and then examine the complex interaction between momentum, buoyancy and (acid) concentration for a turbulent jet with off-source heating. The simulations provide valuable insight into the flow structure, and motivate a reinterpretation of the experimental data.

Aspden, Andrew; Nikiforakis, Nikos; Dalziel, Stuart

2008-11-01

228

A new concept: the use of neutrally-buoyant microemulsions for DNAPL remediation  

Microsoft Academic Search

Even in the absence of mobilization of dense nonaqueous phase liquid (DNAPL), the microemulsion that forms when the surfactant solubilizes a dense contaminant such as trichloroethylene will be more dense than water and tends to migrate downward. This paper addresses the issue of migration with a new concept: surfactant enhanced aquifer remediation at neutral buoyancy. Laboratory results of surfactant remediation

K. Kostarelos; G. A Pope; B. A Rouse; G. M Shook

1998-01-01

229

Shallow and buoyant lithospheric subduction : causes and implications from thermo-chemical numerical modeling  

Microsoft Academic Search

Where two lithospheric plates converge on the Earth, one of them disappears into the mantle. The dominant driving mechanism for plate motion is regarded to be `slab pull': the subducted plate, the slab, exerts a pulling force on the attached plate at the surface. However, what has been puzzling geodynamicists since their discovery in the \\u000aseventies, is that shallow, almost

Jeroen van Hunen

2001-01-01

230

Numerical analysis of buoyant flow in a hemispherical enclosure at high Rayleigh numbers  

Microsoft Academic Search

A numerical analysis is presented for buoyancy driven flow of a Newtonian fluid contained in a two dimensional (R, f) hemispherical enclosure for high Rayleigh (Ra) numbers. It is assumed that the flow is driven by the uniformly distributed internal heat sources within the enclosure. All walls of the cavity are maintained at a constant temperature. Finite volume based SIMPLER

A. Liaqat; A. C. Baytas

2003-01-01

231

Near-Limit Flamelet Phenomena in Buoyant Low Stretch Diffusion Flames Beneath a Solid Fuel.  

National Technical Information Service (NTIS)

A unique near-limit low stretch multidimensional stable flamelet phenomena has been observed for the first time which extends the material flammability limit beyond the one-dimensional low stretch flammability limit to lower burning rates and higher relat...

S. L. Olson J. S. Tien

2000-01-01

232

Laminar round jet diffusion flame buoyant instabilities: Study on the disappearance of varicose structures at ultra-low Froude number  

SciTech Connect

At very low Froude number, buoyancy instabilities of round laminar jet diffusion flames disappear (except for small tip oscillations referred to as flickering) and those flames look stable and smooth. This study examines the contributions of the different phenomena in the flow dynamics that may explain this effect. It is observed that, at ultra-low Froude/Reynolds numbers, the material influenced by buoyancy is the plume of the flame and not the flame itself (reaction zone) that is short. Therefore, the vorticity creation zone does not profit from the reaction neighbourhood promoting a sharp gradient of density. Expansion and stretch are also important as they push vorticity creation terms more inside the flame and closer to the burner rim compared to moderate Froude flames. In these latter, the vorticity is continuously created around the flame reaction zone, along its developed height and closer to the vertical direction (in average). (author)

Boulanger, Joan [Gas Turbine Laboratory, Institute for Aerospace Research, Ottawa, Ontario (Canada)

2010-04-15

233

The wind-forced response on a buoyant coastal current: Observations of the western Gulf of Maine plume  

USGS Publications Warehouse

The Freshwater plume in the western Gulf of Maine is being studied as part of an interdisciplinary investigation of the physical transport of a toxic alga. A field program was conducted in the springs of 1993 and 1994 to map the spatial and temporal patterns of salinity, currents and algal toxicity. The observations suggest that the plume's cross-shore structure varies markedly as a function of fluctuations in alongshore wind forcing. Consistent with Ekman drift dynamics, upwelling favorable winds spread the plume offshore, at times widening it to over 50 km in offshore extent, while downwelling favorable winds narrow the plume width to as little as 10 km. Using a simple slab model, we find qualitative agreement between the observed variations of plume width and those predicted by Ekman theory for short time scales of integration. Near surface current meters show significant correlations between cross-shore currents and alongshore wind stress, consistent with Ekman theory. Estimates of the terms in the alongshore momentum equation calculated from moored current meter arrays also indicate a dominant Ekman balance within the plume. A significant correlation between alongshore currents and winds suggests that interfacial drag may be important, although inclusion of a Raleigh drag term does not significantly improve the alongshore momentum balance.

Fong, D. A.; Geyer, W. R.; Signell, R. P.

1997-01-01

234

A smoothed particle hydrodynamics study on the electrohydrodynamic deformation of a droplet suspended in a neutrally buoyant Newtonian fluid  

NASA Astrophysics Data System (ADS)

In this paper, we have presented a 2D Lagrangian two-phase numerical model to study the deformation of a droplet suspended in a quiescent fluid subjected to the combined effects of viscous, surface tension and electric field forces. The electrostatics phenomena are coupled to hydrodynamics through the solution of a set of Maxwell equations. The relevant Maxwell equations and associated interface conditions are simplified relying on the assumptions of the so-called leaky dielectric model. All governing equations and the pertinent jump and boundary conditions are discretized in space using the incompressible Smoothed Particle Hydrodynamics method with improved interface and boundary treatments. Upon imposing constant electrical potentials to upper and lower horizontal boundaries, the droplet starts acquiring either prolate or oblate shape, and shows rather different flow patterns within itself and in its vicinity depending on the ratios of the electrical permittivities and conductivities of the constituent phases. The effects of the strength of the applied electric field, permittivity, surface tension, and the initial droplet radius on the droplet deformation parameter have been investigated in detail. Numerical results are validated by two highly credential analytical results which have been frequently cited in the literature. The numerically and analytically calculated droplet deformation parameters show good agreement for small oblate and prolate deformations. However, for some higher values of the droplet deformation parameter, numerical results overestimate the droplet deformation parameter. This situation was also reported in literature and is due to the assumption made in both theories, which is that the droplet deformation is rather small, and hence the droplet remains almost circular. Moreover, the flow circulations and their corresponding velocities in the inner and outer fluids are in agreement with theories.

Shadloo, M. S.; Rahmat, A.; Yildiz, M.

2013-09-01

235

Numerical study of wall effects on buoyant gas-bubble rise in a liquid-filled finite cylinder  

PubMed Central

The wall effects on the axisymmetric rise and deformation of an initially spherical gas bubble released from rest in a liquid-filled, finite circular cylinder are numerically investigated. The bulk and gas phases are considered incompressible and immiscible. The bubble motion and deformation are characterized by the Morton number (Mo), Eötvös number (Eo), Reynolds number (Re), Weber number (We), density ratio, viscosity ratio, the ratios of the cylinder height and the cylinder radius to the diameter of the initially spherical bubble (H* = H/d0, R* = R/d0). Bubble rise in liquids described by Eo and Mo combinations ranging from (1,0.01) to (277.5,0.092), as appropriate to various terminal state Reynolds numbers (ReT) and shapes have been studied. The range of terminal state Reynolds numbers includes 0.02 < ReT < 70. Bubble shapes at terminal states vary from spherical to intermediate spherical-cap–skirted. The numerical procedure employs a front tracking finite difference method coupled with a level contour reconstruction of the front. This procedure ensures a smooth distribution of the front points and conserves the bubble volume. For the wide range of Eo and Mo examined, bubble motion in cylinders of height H* = 8 and R* ? 3, is noted to correspond to the rise in an infinite medium, both in terms of Reynolds number and shape at terminal state. In a thin cylindrical vessel (small R*), the motion of the bubble is retarded due to increased total drag and the bubble achieves terminal conditions within a short distance from release. The wake effects on bubble rise are reduced, and elongated bubbles may occur at appropriate conditions. For a fixed volume of the bubble, increasing the cylinder radius may result in the formation of well-defined rear recirculatory wakes that are associated with lateral bulging and skirt formation. The paper includes figures of bubble shape regimes for various values of R*, Eo, Mo, and ReT. Our predictions agree with existing results reported in the literature.

Mukundakrishnan, Karthik; Quan, Shaoping; Eckmann, David M.; Ayyaswamy, Portonovo S.

2009-01-01

236

Numerical study of wall effects on buoyant gas-bubble rise in a liquid-filled finite cylinder  

Microsoft Academic Search

The wall effects on the axisymmetric rise and deformation of an initially spherical gas bubble released from rest in a liquid-filled, finite circular cylinder are numerically investigated. The bulk and gas phases are considered incompressible and immiscible. The bubble motion and deformation are characterized by the Morton number (Mo), Eötvös number (Eo), Reynolds number (Re), Weber number (We), density ratio,

Karthik Mukundakrishnan; Shaoping Quan; David M. Eckmann; Portonovo S. Ayyaswamy

2007-01-01

237

A smoothed particle hydrodynamics study on the electrohydrodynamic deformation of a droplet suspended in a neutrally buoyant Newtonian fluid  

NASA Astrophysics Data System (ADS)

In this paper, we have presented a 2D Lagrangian two-phase numerical model to study the deformation of a droplet suspended in a quiescent fluid subjected to the combined effects of viscous, surface tension and electric field forces. The electrostatics phenomena are coupled to hydrodynamics through the solution of a set of Maxwell equations. The relevant Maxwell equations and associated interface conditions are simplified relying on the assumptions of the so-called leaky dielectric model. All governing equations and the pertinent jump and boundary conditions are discretized in space using the incompressible Smoothed Particle Hydrodynamics method with improved interface and boundary treatments. Upon imposing constant electrical potentials to upper and lower horizontal boundaries, the droplet starts acquiring either prolate or oblate shape, and shows rather different flow patterns within itself and in its vicinity depending on the ratios of the electrical permittivities and conductivities of the constituent phases. The effects of the strength of the applied electric field, permittivity, surface tension, and the initial droplet radius on the droplet deformation parameter have been investigated in detail. Numerical results are validated by two highly credential analytical results which have been frequently cited in the literature. The numerically and analytically calculated droplet deformation parameters show good agreement for small oblate and prolate deformations. However, for some higher values of the droplet deformation parameter, numerical results overestimate the droplet deformation parameter. This situation was also reported in literature and is due to the assumption made in both theories, which is that the droplet deformation is rather small, and hence the droplet remains almost circular. Moreover, the flow circulations and their corresponding velocities in the inner and outer fluids are in agreement with theories.

Shadloo, M. S.; Rahmat, A.; Yildiz, M.

2013-03-01

238

Comparison of dynamic subgrid-scale models for simulations of neutrally buoyant shear-driven atmospheric boundary layer flows  

Microsoft Academic Search

Several non-dynamic, scale-invariant, and scale-dependent dynamic subgrid-scale (SGS) models are utilized in large-eddy simulations\\u000a of shear-driven neutral atmospheric boundary layer (ABL) flows. The popular Smagorinsky closure and an alternative closure\\u000a based on Kolmogorov’s scaling hypothesis are used as SGS base models. Our results show that, in the context of neutral ABL\\u000a regime, the dynamic modeling approach is extremely useful, and

William C. Anderson; Sukanta Basu; Chris W. Letchford

2007-01-01

239

Large-Eddy Simulation of the Neutrally Buoyant Atmospheric Boundary Layer Using two Subgrid-Scale Closures: a Comparative Assessment.  

NASA Astrophysics Data System (ADS)

The traditional Smagorinsky Subgrid-Scale (SGS) closure and its several dynamic variants have been widely used for large-eddy simulation (LES) of high-Reynolds number atmospheric boundary layer (ABL) flows. However, this SGS base model assumes that the energy dissipation rate equals the SGS energy production rate. This strong assumption can be avoided by using a SGS model based on Kolmogorov's scaling hypothesis (Wong and Lilly, 1994). In this work, we take these SGS base models, and make theoretical amendments which allow for scale-dependent dynamic computation of the SGS coefficient (we also use local averaging to account for patchy and sporadic turbulence). These SGS models are used in LES of a well known neutral ABL case-study. We compare simulation results including Monin-Obukhov similarity theory, flow visualizations, energy spectra, and several higher-order statistics. Both the SGS base models demonstrate that, for the physical case considered here, the locally-averaged scale-dependent dynamic modeling approach offers significant benefits. Comparative assessment shows general agreement between the models. Albeit, comparison of the energy spectra illustrates that the Kolmogorov-based SGS model is over-dissipative at the highest wave-numbers. This characteristic is consistent, and we offer flow visualizations which support this position.

Anderson, W. C.; Basu, S.

2006-12-01

240

Near-field mixing of a vertical buoyant jet in a shallow crossflow: Implications on adsorption and flocculation  

Microsoft Academic Search

The behaviour and movement of pulpmill pollutants discharged into the Northern Fraser River is of significant concern due to their potential impact on this valuable aquatic ecosystem. The shallow receiving water can influence the mixing and subsequent dilution of these discharges. The association of contaminants with suspended sediment, either by direct adsorption or flocculation of contaminated solids discharged with the

Leslie Sharon Gomm

1999-01-01

241

Is the 'Fast Halo' around Hawaii as imaged in the PLUME experiment direct evidence for buoyant plume-fed asthenosphere?  

Microsoft Academic Search

An intriguing spatial pattern of variations in shear-wave arrival times has been mapped in the PLUME ocean bottom experiment (Wolfe et al., 2009) around Hawaii. The pattern consists of a halo of fast travel times surrounding a disk of slow arrivals from waves traveling up though the plume. We think it is directly sensing the pattern of dynamic uplift of

J. P. Morgan; C. Shi; J. Hasenclever

2010-01-01

242

Medical Officer's Review Memorandum - Provenge  

Center for Biologics Evaluation and Research (CBER)

Text Version... Sponsor Dendreon Corporation Product(s) Sipuleucel-T (Provenge®) Proposed Use ... on survival, a second trial would not be ethical or feasible. ... More results from www.fda.gov/downloads/biologicsbloodvaccines/cellulargenetherapyproducts

243

Request for Compliance Check for original BLA submission ...  

Center for Biologics Evaluation and Research (CBER)

Text Version... PA2024 Component Dendreon Corporation 3005 First Avenue Seattle, WA 98121 FEI: 3000204836 Testing Testing Diosynth RTP, Inc. ... More results from www.fda.gov/downloads/biologicsbloodvaccines/cellulargenetherapyproducts

244

Response to request for information (January 14) - Provenge ...  

Center for Biologics Evaluation and Research (CBER)

Text Version... Elizabeth C. Smith Vice President of Regulatory Affairs Dendreon Corporation ... With regards to the upper end of the spectrum, when the percent ... More results from www.fda.gov/downloads/biologicsbloodvaccines/cellulargenetherapyproducts

245

Review of the Chemistry, Manufacturing, and Controls Part of ...  

Center for Biologics Evaluation and Research (CBER)

Text Version... Subject: Review of the Chemistry, Manufacturing, and Controls part of the Biological License Application (BLA) submitted by Dendreon Corporation ... More results from www.fda.gov/downloads/biologicsbloodvaccines/cellulargenetherapyproducts

246

Weekly Update Telecon - Provenge  

Center for Biologics Evaluation and Research (CBER)

Text Version... salvage groups • Immunology data - would like Dendreon to discuss this data and what has been learned to date, their ... More results from www.fda.gov/downloads/biologicsbloodvaccines/cellulargenetherapyproducts

247

Record of Telephone Conversation - Provenge, March 5, 2010  

Center for Biologics Evaluation and Research (CBER)

... Dendreon responded that they did not do a hazard analysis, but did do a risk assessment worst case if the timing was off. ... More results from www.fda.gov/biologicsbloodvaccines/cellulargenetherapyproducts/approvedproducts

248

MEMORANDUM Date: January 8, 2007 To: BLA Committee ...  

Center for Biologics Evaluation and Research (CBER)

Text Version... I have reviewed the 3.2.A4 Novel Reagent (PA2024 fusion protein, an ancillary component of Sipuleucel-T) section(s) of Dendreon's BLA ... More results from www.fda.gov/downloads/biologicsbloodvaccines/cellulargenetherapyproducts

249

Review Memo of the Class 2 Response to CR Letter ...  

Center for Biologics Evaluation and Research (CBER)

Text Version... by Dendreon to Seek Licensure of Sipuleucel-T for the Treatment of Men with Asymptomatic, Metastatic Androgen Independent Prostate Cancer ... More results from www.fda.gov/downloads/biologicsbloodvaccines/cellulargenetherapyproducts

250

Type C BLA Teleconference - CMC discussion summary ...  

Center for Biologics Evaluation and Research (CBER)

Text Version... Dendreon responded that these issues could be ... be delivered within the(b)(4)hour shelf life time frame. ... might be able to address this issue with data ... More results from www.fda.gov/downloads/biologicsbloodvaccines/cellulargenetherapyproducts

251

STN 125197/0 Filing Action - Provenge, January 8, 2007  

Center for Biologics Evaluation and Research (CBER)

Text Version... Subject: STN 125197/0 Filing Action ... section(s) of Dendreon's BLA (STN Number 125197/0) and find the application acceptable for filing. ... More results from www.fda.gov/downloads/biologicsbloodvaccines/cellulargenetherapyproducts

252

46 CFR 160.048-6 - Marking.  

Code of Federal Regulations, 2012 CFR

...LIFESAVING EQUIPMENT Specification for a Buoyant Cushion, Fibrous Glass § 160.048-6 Marking. (a) Each buoyant cushion...regulations. Dry out thoroughly when wet. (Kapok or Fibrous glass) buoyant material provides a minimum buoyant force of 20...

2012-10-01

253

1/12-Scale mixing interface visualization and buoyant particle release tests in support of Tank 241-SY-101 hydrogen mitigation.  

National Technical Information Service (NTIS)

In support of tank waste safety programs, visualization tests were performed in the 1/12-scale tank facility, using a low-viscosity simulant. The primary objective of the tests was to obtain video records of the transient jet-sludge interaction. The inten...

E. J. Eschbach C. W. Enderlin

1993-01-01

254

Hypothesis testing of buoyant plume migration using a highly parameterized variable-density groundwater model at a site in Florida, USA  

Microsoft Academic Search

A highly parameterized variable-density groundwater flow and solute transport model was developed to test multiple hypotheses\\u000a for upward movement of treated wastewater (effluent) injected into a saline coastal aquifer in southeastern Florida, USA.\\u000a The model was designed to assess risk to a drinking-water aquifer above the zone of injection, where monitoring wells have\\u000a detected effluent. The model-based analysis accommodated geological

Alyssa M. Dausman; John Doherty; Christian D. Langevin; Joann Dixon

2010-01-01

255

An Experimental Investigation of the Heat Transfer from a Buoyant Gas Plume to a Horizontal Ceiling - Part 2. Effects of Ceiling Layer.  

National Technical Information Service (NTIS)

This report contains the results of experiments carried out as part of a study of heat transfer to room ceilings under conditions similar to those encountered in the early stages of a room fire before the room becomes completely involved in flames. Part 1...

E. E. Zukoski T. Kubota

1975-01-01

256

Common Variants in the Promoter of the Hepatic Lipase Gene Are Associated With Lower Levels of Hepatic Lipase Activity, Buoyant LDL, and Higher HDL2 Cholesterol  

Microsoft Academic Search

Increased hepatic lipase (HL) activity is associated with small, dense, low density lipoprotein (LDL) and low high density lipoprotein2 (HDL2) cholesterol (-C) levels. A polymorphism in the promoter region of the HL gene (LIPC) is associated with HDL-C levels. To test whether this association is mediated by differences in HL activity between different LIPC promoter genotypes, the LIPC promoter polymorphism

Alberto Zambon; Samir S. Deeb; John E. Hokanson; B. Greg Brown; John D. Brunzell

257

46 CFR 160.047-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.  

Code of Federal Regulations, 2012 CFR

...must be constructed of inherently corrosion resistant materials. As used in this section the term inherently corrosion resistant materials includes...pass through the opening. (b) Testing requirements. Dee ring and...

2012-10-01

258

46 CFR 160.052-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.  

Code of Federal Regulations, 2012 CFR

...must be constructed of inherently corrosion resistant materials. As used in this section the term inherently corrosion resistant materials includes...pass through the opening. (b) Testing requirements. Dee ring and...

2012-10-01

259

46 CFR 160.047-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.  

Code of Federal Regulations, 2011 CFR

...must be constructed of inherently corrosion resistant materials. As used in this section the term inherently corrosion resistant materials includes...pass through the opening. (b) Testing requirements. Dee ring and...

2011-10-01

260

46 CFR 160.060-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.  

Code of Federal Regulations, 2012 CFR

...must be constructed of inherently corrosion resistant materials. As used in this section the term inherently corrosion resistant materials includes...pass through the opening. (b) Testing requirements. Dee ring and...

2012-10-01

261

46 CFR 160.060-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.  

Code of Federal Regulations, 2011 CFR

...must be constructed of inherently corrosion resistant materials. As used in this section the term inherently corrosion resistant materials includes...pass through the opening. (b) Testing requirements. Dee ring and...

2011-10-01

262

Ethylene and growth control in the fringed waterlily ( Nymphoides peltata ): Stimulation of cell division and interaction with buoyant tension in petioles  

Microsoft Academic Search

The effect of ethylene on petiole growth of the Fringed Waterlily (Nymphoides peltata (S.G. Gmelin) O. Kuntze) changes during leaf ontogeny. During early development (before expansion of laminae), ethylene causes an increase in both cell number and cell size; later in development, promotion of rapid cell expansion is the dominant effect. The early effects may contribute to the accommodation of

Irene Ridge; Ivan Amarasinghe

1984-01-01

263

COLLABORTIVE RESEARCH: Lagrangian studies of the transport, transformation, and biological impact of nutrients and contaminant metals in a buoyant plume: A process study in an operational ocean observatory  

Microsoft Academic Search

We propose a coordinated program of field and numerical experiments to examine processes that control the fate and transport of nutrients and chemical contaminants in the Hudson River plume, a plume that emanates from one of the nation's most urban estuaries -- the New York\\/New Jersey Harbor complex. Urban estuarine plumes represent a major pathway for the transport of nutrients

Robert Chant; John Reinfelder; Scott Glenn; Oscar Schofield; John Wilkin; Robert Houghton; Bob Chen; Meng Zhou; Paul Bissett; Mark Moline; Tom Frazer

264

46 CFR 160.052-5 - Construction-standard vests.  

Code of Federal Regulations, 2011 CFR

...EQUIPMENT Specification for a Buoyant Vest, Unicellular Plastic Foam, Adult and Child § 160.052-5 Constructionâstandard...the drawings. (c) Buoyant inserts. The unicellular plastic foam buoyant inserts shall be cut and formed as shown on...

2011-10-01

265

46 CFR 160.052-5 - Construction-standard vests.  

Code of Federal Regulations, 2012 CFR

...EQUIPMENT Specification for a Buoyant Vest, Unicellular Plastic Foam, Adult and Child § 160.052-5 Constructionâstandard...the drawings. (c) Buoyant inserts. The unicellular plastic foam buoyant inserts shall be cut and formed as shown on...

2012-10-01

266

46 CFR 160.049-4 - Construction and workmanship.  

Code of Federal Regulations, 2012 CFR

... LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-4 Construction and workmanship. ...covers buoyant cushions of the box type filled with unicellular plastic foam buoyant material. Such cushions consist...

2012-10-01

267

New treatments for metastic prostate cancer.  

PubMed

The FDA has approved 2 new treatments for castration-resistant (formerly called hormone-refractory) prostate cancer. Sipuleucel-T (Provenge - Dendreon) s the first immunotherapy approved for treatment of prostate cancer. Cabazitaxel (Jevtana - Sanofi-Aventis) is approved for second-line treatment of metastatic castration-resistant prostate cancer previously treated with docetaxel (Taxotere). PMID:20814400

2010-09-01

268

Teleconference - Provenge, May 9, 2007  

Center for Biologics Evaluation and Research (CBER)

Text Version... Liz Smith from Dendreon Corporation called me at 8:30 AM ET/5:30PT to have a brief telecom regarding the Complete Response letter that OCTGT ... More results from www.fda.gov/downloads/biologicsbloodvaccines/cellulargenetherapyproducts

269

The influence of buoyant forces and volume fraction of particles on the particle pushing\\/entrapment transition during directional solidification of Al\\/SiC and Al\\/graphite composites  

Microsoft Academic Search

Directional solidification experiments in a Bridgman-type furnace were used to study particle behavior at the liquid\\/solid\\u000a interface in aluminum metal matrix composites. Graphite or siliconcarbide particles were first dispersed in aluminum-base\\u000a alloysvia a mechanically stirred vortex. Then, 100-mm-diameter and 120-mm-long samples were cast in steel dies and used for directional\\u000a solidification. The processing variables controlled were the direction and velocity

Doru M. Stefanescu; Avijit Moitra; A. Sedat Kacar; Brij K. Dhindaw

1990-01-01

270

Active immunotherapeutics forum-Advance phase III active immunotherapy programs: just how well did the pre-clinical and early clinical trials translate? Case studies: with the benefit of hindsight, what are the three biggest lessons learned from pre-clinical and early clinical trials? Meeting report from Barcelona, May 12 2011.  

PubMed

The approval of Provenge (Dendreon) in 2010 signaled the dawn of a new era in the development of active immunotherapeutics. For cancer treatment, the approval of Provenge® demonstrates that the immune system can effectively be harnessed to combat cancer. The outlook for active immunotherapies looks bright in terms of promising new approaches and candidates, as well as novel adjuvants and treatment regimens for therapy development. PMID:21941099

Colón, Will

2011-10-01

271

The role of complement in dendritic cell (DC) control of T-cell subsets.  

PubMed

This section of the Journal of Drugs in Dermatology (JDD) is dedicated to Dendreon's Provenge (Sipuleucel-T), the first therapeutic DC vaccine proven effective and approved by the United States (U.S.) Food and Drug Administration (FDA) for advanced cancer. This editorial will discuss three articles in this issue, their relationship to Provenge and the recent TH17-Treg subsets that are regulated by CD46. PMID:21061758

Levis, William R; Martiniuk, Frank

2010-11-01

272

46 CFR 164.015-2 - Types.  

Code of Federal Regulations, 2012 CFR

...Types. (a) Unicellular expanded polyvinyl chloride-acetate copolymer or synthetic rubber modified polyvinyl chloride, polymer or copolymer plastic foam shall be of three types as follows: Type Aâfor life preservers, buoyant vests or buoyant...

2012-10-01

273

46 CFR 164.015-2 - Types.  

Code of Federal Regulations, 2011 CFR

...Types. (a) Unicellular expanded polyvinyl chloride-acetate copolymer or synthetic rubber modified polyvinyl chloride, polymer or copolymer plastic foam shall be of three types as follows: Type Aâfor life preservers, buoyant vests or buoyant...

2011-10-01

274

46 CFR 160.073-20 - Marking.  

Code of Federal Regulations, 2011 CFR

...SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Float-Free Link or Life Floats and Buoyant Apparatus § 160.073-20...the appropriate entries in the indicated space): FLOAT-FREE LINK FOR LIFE FLOATS AND BUOYANT APPARATUS Of (10 or...

2011-10-01

275

46 CFR 160.048-2 - Types and sizes.  

Code of Federal Regulations, 2012 CFR

...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion, Fibrous Glass § 160.048-2 Types and sizes. (a) Types. Buoyant cushions shall be of the box type, i.e., have top,...

2012-10-01

276

Submarine Deployed Sea-State Sensor.  

National Technical Information Service (NTIS)

A submarine deployed sea state sensor comprises an elongated housing having a nose cone and an aft end, the housing having a forward buoyant chamber for receiving an accelerometer. Aft of the buoyant chamber, a damping assembly communication link deployme...

D. H. Shonting

1996-01-01

277

46 CFR 160.049-1 - Incorporation by reference.  

Code of Federal Regulations, 2011 CFR

...EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-1 Incorporation by... 160.055âLife Preservers, Unicellular Plastic Foam, Adult and Child. 164.015âPlastic Foam, Unicellular, Buoyant, Sheet and...

2011-10-01

278

46 CFR 160.052-8 - Marking.  

Code of Federal Regulations, 2011 CFR

...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Plastic Foam, Adult and Child § 160.052-8 Marking. (a) Each buoyant vest must have the following information...

2011-10-01

279

46 CFR 160.049-7 - Procedure for approval.  

Code of Federal Regulations, 2011 CFR

... LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-7 Procedure for approval. (a) Group...granted separately to each manufacturer for each unicellular plastic foam buoyant cushion he proposes to manufacture which...

2011-10-01

280

46 CFR 160.049-6 - Marking.  

Code of Federal Regulations, 2011 CFR

...EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-6 Marking. (a) Each buoyant cushion must have the following information clearly marked in...

2011-10-01

281

46 CFR 160.052-2 - Size and model.  

Code of Federal Regulations, 2011 CFR

...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Plastic Foam, Adult and Child § 160.052-2 Size and model. (a) A standard buoyant vest is manufactured in accordance...

2011-10-01

282

46 CFR 160.052-1 - Incorporation by reference.  

Code of Federal Regulations, 2012 CFR

...Specification for a Buoyant Vest, Unicellular Plastic Foam, Adult and Child § 160.052-1... 160.055âLife Preservers, Unicellular Plastic Foam, Adult and Child. 164.015âPlastic Foam, Unicellular, Buoyant Sheet and...

2012-10-01

283

46 CFR 160.049-7 - Procedure for approval.  

Code of Federal Regulations, 2012 CFR

... LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-7 Procedure for approval. (a) Group...granted separately to each manufacturer for each unicellular plastic foam buoyant cushion he proposes to manufacture which...

2012-10-01

284

46 CFR 160.049-1 - Incorporation by reference.  

Code of Federal Regulations, 2012 CFR

...EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-1 Incorporation by... 160.055âLife Preservers, Unicellular Plastic Foam, Adult and Child. 164.015âPlastic Foam, Unicellular, Buoyant, Sheet and...

2012-10-01

285

46 CFR 160.060-8 - Marking.  

Code of Federal Regulations, 2012 CFR

...for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-8 Marking. (a) Each buoyant vest must...hours submergence in water it will withstand vigorous rubbing by hand while wet without printed matter becoming illegible....

2012-10-01

286

46 CFR 160.010-2 - Definitions.  

Code of Federal Regulations, 2012 CFR

...Inflatable buoyant apparatus. An inflatable buoyant apparatus is flotation equipment that depends on inflated compartments for buoyancy and is designed to support a specified number of persons completely out of the water. [CGD 79-167, 47 FR 41372,...

2012-10-01

287

46 CFR 160.010-2 - Definitions.  

Code of Federal Regulations, 2011 CFR

...Inflatable buoyant apparatus. An inflatable buoyant apparatus is flotation equipment that depends on inflated compartments for buoyancy and is designed to support a specified number of persons completely out of the water. [CGD 79-167, 47 FR 41372,...

2011-10-01

288

46 CFR 160.055-5 - Construction-standard life preservers.  

Code of Federal Regulations, 2010 CFR

...device is constructed from one piece of unicellular plastic foam with neck hole and the body slit in the front, vinyl dip coating, and fitted and adjustable body strap. (1) Buoyant material. The buoyant material of the life preserver...

2010-10-01

289

33 CFR 175.23 - Serviceable condition.  

Code of Federal Regulations, 2013 CFR

...that has become hardened, non-resilient, permanently compressed, waterlogged, oil-soaked, or which shows evidence of fungus or mildew; or (3) Loss of buoyant material or buoyant material that is not securely held in position. (c) In...

2013-07-01

290

46 CFR 160.060-7 - Inspections and tests-standard and nonstandard vests. 1  

Code of Federal Regulations, 2012 CFR

...Unicellular Polyethylene Foam, Adult and Child § 160.060-7 Inspections and...fresh water; the inserts from the child medium size buoyant vests shall provide...buoyancy; and the inserts from the child small size buoyant vests shall...

2012-10-01

291

46 CFR 160.060-7 - Inspections and tests-standard and nonstandard vests. 1  

Code of Federal Regulations, 2011 CFR

...Unicellular Polyethylene Foam, Adult and Child § 160.060-7 Inspections and...fresh water; the inserts from the child medium size buoyant vests shall provide...buoyancy; and the inserts from the child small size buoyant vests shall...

2011-10-01

292

Explosive volcanic eruptions from linear vents on Earth, Venus, and Mars: Comparisons with circular vent eruptions  

Microsoft Academic Search

Conditions required to support buoyant convective plumes are investigated for explosive volcanic eruptions from circular and linear vents on Earth, Venus, and Mars. Vent geometry (linear versus circular) plays a significant role in the ability of an explosive eruption to sustain a buoyant plume. On Earth, linear and circular vent eruptions are both capable of driving buoyant plumes to equivalent

Lori S. Glaze; Stephen M. Baloga; Jesse Wimert

2011-01-01

293

CONSEQUENCES OF NON-LINEAR DENSITY EFFECTS ON BUOYANCY AND PLUME BEHAVIOR  

EPA Science Inventory

Aquatic plumes, as turbulent streams, grow by entraining ambient water. Buoyant plumes rise and dense ones sink, but, non-linear kinetic effects can reverse the buoyant force in mid-phenomenon. The class of nascent-density plumes begin as buoyant, upwardly accelerating plumes tha...

294

46 CFR 164.013-4 - Samples submitted for acceptance.  

Code of Federal Regulations, 2011 CFR

...SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL MATERIALS Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal Pattern) § 164.013-4 Samples submitted for acceptance. Application...

2011-10-01

295

46 CFR 164.013-7 - Marking.  

Code of Federal Regulations, 2011 CFR

...SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL MATERIALS Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal Pattern) § 164.013-7 Marking. (a) General. The manufacturer...

2011-10-01

296

46 CFR 160.064-2 - Types and models.  

Code of Federal Regulations, 2011 CFR

...HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Marine Buoyant Devices § 160...safety in various fields of water sports or boating activities. (c)...

2011-10-01

297

46 CFR 160.064-2 - Types and models.  

Code of Federal Regulations, 2012 CFR

...HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Marine Buoyant Devices § 160...safety in various fields of water sports or boating activities. (c)...

2012-10-01

298

Some chemical and physical properties of 18 tobacco mosaic virus isolates from tomato  

Microsoft Academic Search

From 18 tobacco mosaic virus isolates from tomato, which could be divided into 3 pathogenicity groups, the buoyant density, the S value, the base composition, the amino acid composition, and the behaviour of their tryptic peptides in thin-layer chromatography were compared. There were no differences in buoyant densities and S values. With respect to the other characteristics only small individual

W. H. M. Mosch; H. Huttinga; A. Th. B. Rast

1973-01-01

299

REMOVING WATER-SOLUBLE HAZARDOUS MATERIAL SPILLS FROM WATERWAYS WITH CARBON  

EPA Science Inventory

A model for the removal of water-soluble organic materials from water by carbon-filled, buoyant packets and panels is described. Based on this model, equations are derived for the removal of dissolved organic compounds from waterways by buoyant packets that are either (a) cycled ...

300

46 CFR 160.052-8 - Marking.  

Code of Federal Regulations, 2012 CFR

...Specification for a Buoyant Vest, Unicellular Plastic Foam, Adult and Child § 160.052-8 Marking. (a) Each buoyant vest must...hours submergence in water it will withstand vigorous rubbing by hand while wet without the printed matter becoming illegible....

2012-10-01

301

46 CFR 160.047-6 - Marking.  

Code of Federal Regulations, 2012 CFR

...Specification for a Buoyant Vest, Kapok or Fibrous Glass, Adult and Child § 160.047-6 Marking. (a) Each buoyant vest must...submergence in water, it will withstand vigorous rubbing by hand while wet without the printed matter becoming illegible....

2012-10-01

302

46 CFR 160.047-6 - Marking.  

Code of Federal Regulations, 2011 CFR

...Specification for a Buoyant Vest, Kapok or Fibrous Glass, Adult and Child § 160.047-6 Marking. (a) Each buoyant vest must...submergence in water, it will withstand vigorous rubbing by hand while wet without the printed matter becoming illegible....

2011-10-01

303

Rapid Separation and Concentration of Food-Borne Pathogens in Food Samples Prior to Quantification by Viable-Cell Counting and Real-Time PCR  

Microsoft Academic Search

Buoyant density gradient centrifugation has been used to separate bacteria from complex food matrices, as well as to remove compounds that inhibit rapid detection methods, such as PCR, and to prevent false-positive results due to DNA originating from dead cells. Applying a principle of buoyant density gradient centrifuga- tion, we developed a method for rapid separation and concentration following filtration

Hiroshi Fukushima; Kazunori Katsube; Y. Hata; Ryoko Kishi; Satomi Fujiwara

2007-01-01

304

The gas content and buoyancy of strombolian ash plumes  

Microsoft Academic Search

Plinian plumes erupt with a bulk density greater than that of air, and depend upon air entrainment during their gas-thrust phase to become buoyant; if entrainment is insufficient, the column collapses into a potentially deadly pyroclastic flow. This study shows that strombolian ash plumes can be erupted in an initially buoyant state due to their extremely high initial gas content,

Matthew Patrick

2007-01-01

305

Flow visualization and numerical modeling for the gradient freeze configuration during centrifugation  

Microsoft Academic Search

A visualization system was constructed for observation of buoyant convection in the gradient freeze configuration during centrifugation. The buoyant convective flow was observed in the tangential cross-section and two horizontal cross-sections of the test cell. Without centrifugation, the usual axisymmetric flow pattern with a toroidal vortex near the bottom of the test cell was observed. With centrifugation, the flow in

Peter Victorovich Skudarnov

1999-01-01

306

Deep water riser system for offshore drilling  

Microsoft Academic Search

A buoyant riser system for use in a deep water offshore drilling environment is anchored by a system of compliant guys below the active weather zone of the sea. A controllably buoyant housing of the system is submerged at a depth that is readily accessible to divers and includes a blow-out preventer (BOP) from which a suspended sub-riser leads to

1984-01-01

307

Mesoscale Currents on the Inner New Jersey Shelf Driven by the Interaction of Buoyancy and Wind Forcing  

Microsoft Academic Search

Shipboard hydrographic and acoustic Doppler current profiler surveys conducted in August 1996 on the New Jersey inner shelf revealed a buoyant intrusion advancing southward along the coast. This buoyant intrusion originated from the Hudson estuary more than 100 km upshelf and appeared as a bulge of less saline water with a sharp across-shelf frontal zone at its leading edge. During

Alexander E. Yankovsky; Richard W. Garvine; Andreas Münchow

2000-01-01

308

Free oscillations of a balanced ball on the horizon of neutral buoyancy in a continuously stratified fluid  

Microsoft Academic Search

Interest in the investigation of free oscillations of neutrally buoyant bodies in stratified fluids [1, 2], which arises from the practical needs of undersea navigation, has increased in the past few years owing to the fact that the number of neutrally buoyant probes drifting in the atmosphere and hydrosphere is progressively increasing [3]. The work program involves regular surfacing of

A. Yu. Vasil’ev; A. V. Kistovich; Yu. D. Chashechkin

2007-01-01

309

30 CFR 250.910 - Which of my facilities are subject to the Platform Verification Program?  

Code of Federal Regulations, 2013 CFR

...platform is a buoyant offshore facility that does not...production, and pipeline risers, and riser tensioning...imposed by all risers and riser does not have tensioning...platform is a buoyant offshore facility with a ship-shaped...production, and pipeline risers, and riser...

2013-07-01

310

Dimensions and dynamics of megaplumes  

Microsoft Academic Search

We investigate the generation of megaplumes by the release of buoyant hydrothermal fluid from the seafloor. We show that megaplumes may be generated from various modes of venting, including both the instantaneous and continuous release of hydrothermal effluent from either a point or line source. The hydrothermal effluent forms a buoyant plume, which rises through the water column to its

Andrew W. Woods; John W. M. Bush

1999-01-01

311

BATHYMETRIC IRREGULARITIES, JET FORMATION, AND SUBSEQUENT MIXING PROCESSES  

EPA Science Inventory

It is well known that bathymetric contours influence and steer currents and that irregularities in bathymetry contribute to the formation of aquatic non-buoyant jets and buoyant plumes. For example, bathymetric irregularities can channel flow through canyons or accelerate flow ov...

312

Method of controlling displacement of propping agent in fracturing treatments  

Microsoft Academic Search

A method of preventing overdisplacement of propping agent particles during well treatments to hydraulically induce a fracture in a subterranean formation wherein buoyant or neutrally buoyant ball sealers are incorporated in the trailing end portion of the fracturing fluid. The ball sealers seat on at least some of the well perforations in final stages of particle injection thereby causing the

S. R. Erbstoesser; R. L. Graham

1983-01-01

313

Effects of volcano loading on dike propagation in an elastic half-space  

Microsoft Academic Search

We use laboratory experiments and numerical models to examine the effects of volcano loading on the propagation of buoyant dikes in a two-dimensional elastic half-space. In laboratory experiments we simulate the propagation of buoyant dikes in an isotropic regional stress field by injecting air into tanks of solidified gelatin. A weight resting on the surface of the gelatin represents a

Jordan R. Muller; Garrett Ito; Stephen J. Martel

2001-01-01

314

Pitch period reduction apparatus for tension leg platforms  

SciTech Connect

An apparatus is described for use in decreasing the pitch period of a tension leg platform, the platform having a center of gravity and floating in a body of water having a marine bottom. The platform has interior buoyant member means, the upper portion of the interior buoyant member means connected to a deck mass, the lower portion of the interior buoyant member means operatively engaged in tension to anchor means secured to the marine bottom. The interior buoyant means arranged in a manner wherein they form the corners of a horizontal interior polygon about the center of gravity of the platform. The apparatus consists of: exterior buoyant member means in the form of buoyant columns operatively connected to the interior buoyant member means, the exterior buoyant member means arranged in a manner wherein they form the corners of a horizontal exterior polygon, at least a portion of the sides of the exterior polygon located outside the sides of the interior polygon, when viewed from a direction perpendicular to the interior and exterior polygons.

Collip, B.G.

1986-04-29

315

Growth of the hemispheric dichotomy and the cessation of plate tectonics on Mars  

Microsoft Academic Search

Although Mars is currently not tectonically active, it may have experienced plate tectonics early in its history. The southern hemisphere of Mars possesses a thick crust which probably renders the lithosphere positively buoyant. In this paper we present numerical and scaling arguments which show that if the area of positively buoyant lithosphere grows beyond a critical fraction (?50% for Mars),

A. Lenardic; F. Nimmo; L. Moresi

2004-01-01

316

Growth of the hemispheric dichotomy and the cessation of plate tectonics on Mars  

Microsoft Academic Search

Although Mars is currently not tectonically active, it may have experienced plate tectonics early in its history. The southern hemisphere of Mars possesses a thick crust which probably renders the lithosphere positively buoyant. We present numerical and scaling arguments which show that if the area of positively buoyant lithosphere grows beyond a critical fraction, plate tectonics will stop. Heat transfer

A. Lenardic; F. Nimmo; L. Moresi; M. Collier

2004-01-01

317

A computer program for simulating the atmospheric dispersion of UF/sub 6/ and other reactive gases having positive, neutral, or negative buoyancy  

SciTech Connect

This report describes a mathematical model which was developed to simulate the atmospheric dispersion of chemically reactive gases that may be neutrally buoyant, positively buoyant, or negatively buoyant with respect to the ambient air. Emphasis is on materials used at uranium enrichment facilities, particularly uranium hexafluoride and its hydrolysis products. The report discusses the mathematical principles of the model, the chemical and physical properties used in the model, the computer program which was developed to perform the calculations, and the iterative techniques used in the model. Descriptions of the computer program are given as appendices. 41 refs., 18 figs., 27 tabs.

Bloom, S.G.; Just, R.A.; Williams, W.R.

1989-03-01

318

Immunotherapy for prostate cancer using prostatic acid phosphatase loaded antigen presenting cells.  

PubMed

Dendritic cells from patients with cancer are deficient in number and functional activity, leading to inadequate tumor immunosurveillance as a result of poor induction of T-cell antitumor responses. Loaded dendritic cell therapy is a vaccination strategy aimed at eliciting tumor antigen-specific, T-cell immune responses. Loaded dendritic cell therapy using prostatic acid phosphatase (APC8015; Provenge, Dendreon Corp., Seattle, WA) as an immunogen has shown a survival benefit in patients with metastatic hormone-refractory prostate cancer in a randomized phase III trial. This review will summarize the prostate cancer clinical trials using APC8015 and discuss the potential future role of APC8015 in prostate cancer treatment. PMID:16962496

Lin, Amy M; Hershberg, Robert M; Small, Eric J

319

Immunotherapy for prostate cancer using antigen-loaded antigen-presenting cells: APC8015 (Provenge).  

PubMed

Dendritic cells are deficient both in number and function in patients with cancer. Loaded dendritic cell therapies aim to overcome this deficiency by delivering antigens to antigen-presenting cells under ex vivo conditions, improving dendritic cell function. APC8015 (Provenge; Dendreon Corp., Seattle, WA) is a novel immunotherapeutic, which consists of autologous dendritic cells pulsed ex vivo with PA2024, a recombinant fusion protein consisting of granulocyte macrophage colony-stimulating factor and prostatic acid phosphatase, as an immunogenic agent. A Phase III randomized clinical trial has demonstrated a survival benefit in patients with metastatic hormone-refractory prostate cancer. This review summarizes the clinical trials using APC8015 in prostate cancer and discusses its future role in the treatment of prostate cancer. PMID:17696825

Harzstark, Andrea L; Small, Eric J

2007-08-01

320

Sipuleucel-T (APC8015) for prostate cancer.  

PubMed

Sipuleucel-T (Provenge; APC8015; Dendreon Corp, WA, USA) is a novel immunotherapeutic cellular product, which includes autologous dendritic cells pulsed ex vivo with a recombinant fusion protein (PA2024) consisting of granulocyte macrophage colony-stimulating factor and prostatic acid phosphatase. Two Phase II trials in men with androgen-dependent biochemically relapsed prostate cancer have demonstrated a decrease in prostate-specific antigen and prolongation in prostate-specific antigen doubling time. In men with hormone-refractory prostate cancer, clinical trials have demonstrated both biological activity and clinical response to sipuleucel-T. Data from two Phase III trials in men with asymptomatic, metastatic hormone-refractory prostate cancer demonstrated an improved median overall survival in men who received sipuleucel-T compared with placebo. Clinical trials are ongoing or are being developed to evaluate sipuleucel-T in various prostate cancer disease states and in combination with other treatment modalities. PMID:17020451

So-Rosillo, Rosendo; Small, Eric J

2006-09-01

321

46 CFR 160.171-1 - Scope.  

Code of Federal Regulations, 2012 CFR

...performance requirements, and approval tests for adult and child insulated, buoyant immersion suits that are designed to prevent shock upon entering cold water and lessen the effect of hypothermia (extreme body heat loss due to immersion in cold water)....

2012-10-01

322

46 CFR 160.171-1 - Scope.  

Code of Federal Regulations, 2011 CFR

...performance requirements, and approval tests for adult and child insulated, buoyant immersion suits that are designed to prevent shock upon entering cold water and lessen the effect of hypothermia (extreme body heat loss due to immersion in cold water)....

2011-10-01

323

46 CFR 160.048-8 - Recognized laboratory.  

Code of Federal Regulations, 2012 CFR

...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion, Fibrous Glass § 160.048-8 Recognized laboratory. (a) A manufacturer seeking Coast Guard approval of a product under...

2012-10-01

324

46 CFR 160.047-7 - Recognized laboratory.  

Code of Federal Regulations, 2012 CFR

...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Kapok or Fibrous Glass, Adult and Child § 160.047-7 Recognized laboratory. (a) A manufacturer seeking Coast Guard approval of...

2012-10-01

325

46 CFR 160.048-3 - Materials.  

Code of Federal Regulations, 2012 CFR

...EQUIPMENT Specification for a Buoyant Cushion, Fibrous Glass § 160.048-3 Materials. (a) General...subchapter and shall be properly processed. (c) Fibrous glass. The fibrous glass shall comply with the requirements of...

2012-10-01

326

Structure of laboratory ball lightning.  

PubMed

Trajectories of self-sustained laboratory ball lightning, generated by arc discharges with silicon, are investigated for understanding the possibility of buoyant flight. Extremely low apparent densities are found, nearly approaching that of standard air. The freely buoyant balls are observed to survive for about 0.1 s, with significantly buoyant balls surviving for several seconds. These ball lightning objects are found to have a density and size that can easily allow them to be carried by a gentle breeze of a few meters per second. The results are interpreted by a model that is an extension of that first proposed by Abrahamson and Dinniss [J. Abrahamson and J. Dinniss, Nature (London) 403, 519 (2000)]. The buoyant behavior of ball lightning seen in our experiments is believed to arise as a result of the formation of a nanoparticle oxide network growing from a molten silicon core. PMID:20365306

Ito, Tsuyohito; Tamura, Tomoya; Cappelli, Mark A; Hamaguchi, Satoshi

2009-12-07

327

Structure of laboratory ball lightning  

NASA Astrophysics Data System (ADS)

Trajectories of self-sustained laboratory ball lightning, generated by arc discharges with silicon, are investigated for understanding the possibility of buoyant flight. Extremely low apparent densities are found, nearly approaching that of standard air. The freely buoyant balls are observed to survive for about 0.1 s, with significantly buoyant balls surviving for several seconds. These ball lightning objects are found to have a density and size that can easily allow them to be carried by a gentle breeze of a few meters per second. The results are interpreted by a model that is an extension of that first proposed by Abrahamson and Dinniss [J. Abrahamson and J. Dinniss, Nature (London) 403, 519 (2000)]. The buoyant behavior of ball lightning seen in our experiments is believed to arise as a result of the formation of a nanoparticle oxide network growing from a molten silicon core.

Ito, Tsuyohito; Tamura, Tomoya; Cappelli, Mark A.; Hamaguchi, Satoshi

2009-12-01

328

46 CFR 160.050-3 - Materials.  

Code of Federal Regulations, 2012 CFR

...other suitable buoyant type synthetic material having a minimum breaking strength of 1,350 pounds. (d) Beckets...saran or other suitable synthetic material having a minimum breaking strength of 585 pounds. In addition,...

2012-10-01

329

46 CFR 28.130 - Survival craft equipment.  

Code of Federal Regulations, 2011 CFR

...SECURITY UNINSPECTED VESSELS REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Requirements for All Vessels § 28.130...Limited Serviceâ); or (3) SOLAS A Pack (formerly âOcean Serviceâ). (c) Each life float and buoyant...

2011-10-01

330

46 CFR 28.130 - Survival craft equipment.  

Code of Federal Regulations, 2012 CFR

...SECURITY UNINSPECTED VESSELS REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Requirements for All Vessels § 28.130...Limited Serviceâ); or (3) SOLAS A Pack (formerly âOcean Serviceâ). (c) Each life float and buoyant...

2012-10-01

331

Systems Development for Environmental Impact Assessment of Concentrate Disposal Development of Density Current Simulation Models, Rule Base, and Graphic User Inteface. Desalination and Water Purification Research and Development Program Report No. 132.  

National Technical Information Service (NTIS)

This project developed hydrodynamic models to simulate the mixing of point source concentrate discharges. The CORMIX system was modified to incorporate negatively buoyant surface (shoreline) discharge sources and models to simulate density current mixing ...

R. L. Doneker

2006-01-01

332

46 CFR 164.013-5 - Acceptance tests.  

Code of Federal Regulations, 2011 CFR

...SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL MATERIALS Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal Pattern) § 164.013-5 Acceptance tests. Manufacturers shall ensure that...

2011-10-01

333

46 CFR 160.064-6 - Examinations, tests and inspections.  

Code of Federal Regulations, 2011 CFR

...tests. Manufacturers of listed and labeled water safety buoyant devices shall maintain quality control of the materials used, manufacturing...samples and components produced to maintain the quality of the finished product. Records of...

2011-10-01

334

46 CFR 160.052-9 - Recognized laboratory.  

Code of Federal Regulations, 2011 CFR

...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Plastic Foam, Adult and Child § 160.052-9 Recognized laboratory. (a) A manufacturer seeking Coast Guard...

2011-10-01

335

46 CFR 160.049-8 - Recognized laboratory.  

Code of Federal Regulations, 2011 CFR

...EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-8 Recognized laboratory. (a) A manufacturer seeking Coast Guard approval of a product...

2011-10-01

336

46 CFR 164.015-5 - Procedure for acceptance.  

Code of Federal Regulations, 2011 CFR

...SPECIFICATIONS AND APPROVAL MATERIALS Plastic Foam, Unicellular, Buoyant, Sheet and...Procedure for acceptance. (a) Unicellular plastic foam is not subject to formal approval...manufacturer. (c) Acceptance of unicellular plastic foam prior to being incorporated...

2011-10-01

337

46 CFR 160.049-5 - Inspections and tests. 1  

Code of Federal Regulations, 2011 CFR

...EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-5 Inspections and tests. 1 1 The manufacturer of a personal flotation device must meet 33...

2011-10-01

338

46 CFR 164.015-3 - Material and workmanship.  

Code of Federal Regulations, 2011 CFR

...SPECIFICATIONS AND APPROVAL MATERIALS Plastic Foam, Unicellular, Buoyant, Sheet and...workmanship. (a) The unicellular plastic foam shall be all new material complying...015-4(a). (b) The unicellular plastic foam shall be produced in sheet stock...

2011-10-01

339

46 CFR 160.055-6 - Construction-nonstandard, life preservers.  

Code of Federal Regulations, 2011 CFR

...APPROVAL LIFESAVING EQUIPMENT Life Preservers, Unicellular Plastic Foam, Adult and Child, for Merchant Vessels § 160.055-6...nonstandard life preserver must contain the following volume of plastic foam buoyant material, determined by the displacement...

2011-10-01

340

Ejection Device for Aircraft Crash Dye Marker.  

National Technical Information Service (NTIS)

The buoyant marker is mounted on an aircraft. When activated the marker indicates the point at which an aircraft sank into water. An explosive is used to release a gas which drives the marker buoy from the aircraft.

J. Mellon J. Harding W. J. Zarkowski

1964-01-01

341

Analytical and Numerical Studies of the Thermocapillary Flow in a Uniformly Floating Zone.  

National Technical Information Service (NTIS)

The microgravity environment of an orbiting vehicle permits crystal growth experiments in the presence of greatly reduced buoyant convection in the liquid melt. Crystals grown in ground-based laboratories do not achieve their potential properties because ...

W. W. Fowlis G. O. Roberts

1986-01-01

342

Exploration of the North Atlantic Current and Its Recirculation in the Newfoundland Basin Using SOFAR Floats.  

National Technical Information Service (NTIS)

Trajectories and time series of velocity, temperature, and pressure are presented for 13 neutrally-buoyant, acoustically tracked (SOFAR) floats that were launched in May and June, 1986 in the Newfoundland Basin by the Woods Hole Oceanographic Institution ...

W. B. Owens M. E. Zemanovic

1990-01-01

343

46 CFR 160.049-8 - Recognized laboratory.  

Code of Federal Regulations, 2012 CFR

...EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-8 Recognized laboratory. (a) A manufacturer seeking Coast Guard approval of a product...

2012-10-01

344

46 CFR 164.015-5 - Procedure for acceptance.  

Code of Federal Regulations, 2012 CFR

...SPECIFICATIONS AND APPROVAL MATERIALS Plastic Foam, Unicellular, Buoyant, Sheet and...Procedure for acceptance. (a) Unicellular plastic foam is not subject to formal approval...manufacturer. (c) Acceptance of unicellular plastic foam prior to being incorporated...

2012-10-01

345

46 CFR 164.015-3 - Material and workmanship.  

Code of Federal Regulations, 2012 CFR

...SPECIFICATIONS AND APPROVAL MATERIALS Plastic Foam, Unicellular, Buoyant, Sheet and...workmanship. (a) The unicellular plastic foam shall be all new material complying...015-4(a). (b) The unicellular plastic foam shall be produced in sheet stock...

2012-10-01

346

46 CFR 109.334 - Working over water.  

Code of Federal Regulations, 2010 CFR

...OPERATIONS Operation and Stowage of Safety Equipment § 109.334 Working over water. The master or person in charge shall insure that each person working over the water is wearing a life preserver or a buoyant work...

2010-10-01

347

46 CFR 109.334 - Working over water.  

Code of Federal Regulations, 2010 CFR

...OPERATIONS Operation and Stowage of Safety Equipment § 109.334 Working over water. The master or person in charge shall insure that each person working over the water is wearing a life preserver or a buoyant work...

2009-10-01

348

46 CFR 160.073-5 - Certification.  

Code of Federal Regulations, 2011 CFR

...MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Float-Free Link or Life Floats and Buoyant Apparatus § 160.073-5 Certification. (a) The float-free link is not approved by the Coast Guard. The manufacturer of the...

2011-10-01

349

Design and Evaluation of a Diver-Controlled Monopropellant Hydrazine Gas Generator Buoyancy System.  

National Technical Information Service (NTIS)

Based on previous experimental effort in monopropellant gas generator (MOG) powered buoyant lift systems and on discussions with Navy personnel, the concept of a small, diver-controlled buoyancy lift system was evolved. Pursuant to development of such a s...

D. Miller

1969-01-01

350

46 CFR 160.176-23 - Marking.  

Code of Federal Regulations, 2011 CFR

...manual and user's manual ). When fully inflated this lifejacket provides a minimum buoyant force of (insert the design buoyancy in lb. ). (d) Other Information. Each lifejacket must also be marked with the following information below the...

2011-10-01

351

46 CFR 160.027-2 - Type.  

Code of Federal Regulations, 2012 CFR

...requirements in subpart 160.010 of this chapter for a peripheral body type buoyant apparatus designed so that persons supported are only partially immersed (180 N (40 lb.) of buoyancy per person required). (b)...

2012-10-01

352

46 CFR 160.027-2 - Type.  

Code of Federal Regulations, 2011 CFR

...requirements in subpart 160.010 of this chapter for a peripheral body type buoyant apparatus designed so that persons supported are only partially immersed (180 N (40 lb.) of buoyancy per person required). (b)...

2011-10-01

353

46 CFR 160.176-23 - Marking.  

Code of Federal Regulations, 2012 CFR

...manual and user's manual ). When fully inflated this lifejacket provides a minimum buoyant force of (insert the design buoyancy in lb. ). (d) Other Information. Each lifejacket must also be marked with the following information below the...

2012-10-01

354

Hydrodynamic Suppression of Soot Formation in Laminar Coflowing Jet Diffusion Flames.  

National Technical Information Service (NTIS)

Effects of flow (hydrodynamic) properties on limiting conditions for soot-free laminar non-premixed hydrocarbon/air flames (called laminar soot-point conditions) were studied, emphasizing non-buoyant laminar coflowing jet diffusion flames. Effects of air/...

Z. Dai G. M. Faeth

2000-01-01

355

Modeling the atmospheric dispersion of accidentally released heavy gases from photovoltaic cell manufacturing facilities.  

National Technical Information Service (NTIS)

Many hazardous gases used in the photovoltaic cell industry are heavier than air. Following an accidental release, their dispersion in air, differs from the dispersion of a neutrally buoyant gas and, as such, it requires special consideration. This report...

V. M. Fthenakis

1986-01-01

356

Powering Prediction for Various Hybrid Ship Concepts.  

National Technical Information Service (NTIS)

A computer program called TRIBRID is described which can rapidly calculate the smooth water resistances of some advanced hybrid and tribrid ship concepts that are supported by buoyant, dynamic, and aerostatic forces. These forces are produced by one or mo...

G. Karafiath

1976-01-01

357

30 CFR 250.910 - Which of my facilities are subject to the Platform Verification Program?  

Code of Federal Regulations, 2010 CFR

...tensioning systems (each platform must be designed...Your new floating platform is a buoyant offshore facility with a ship-shaped...associated with a floating platform are subject to the...affecting the structural integrity of a portion or...

2009-07-01

358

30 CFR 250.910 - Which of my facilities are subject to the Platform Verification Program?  

Code of Federal Regulations, 2010 CFR

...tensioning systems (each platform must be designed...Your new floating platform is a buoyant offshore facility with a ship-shaped...associated with a floating platform are subject to the...affecting the structural integrity of a portion or...

2010-07-01

359

46 CFR 160.060-6 - Construction-nonstandard vests.  

Code of Federal Regulations, 2011 CFR

...Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-6 Constructionânonstandard vests...Three hundred and fifty cubic inches or more for a child medium size, for children weighing from 50 to 90 pounds. (3) Two...

2011-10-01

360

46 CFR 160.060-6 - Construction-nonstandard vests.  

Code of Federal Regulations, 2012 CFR

...Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-6 Constructionânonstandard vests...Three hundred and fifty cubic inches or more for a child medium size, for children weighing from 50 to 90 pounds. (3) Two...

2012-10-01

361

46 CFR 160.077-2 - Definitions.  

Code of Federal Regulations, 2012 CFR

...inherently buoyant material. (e) Inflation medium means any solid, liquid, or gas, that...means a model AK-1, adult PFD; model CKM-1, child medium PFD; or model CKS-2, child small PFD, meeting the...

2012-10-01

362

46 CFR 160.077-2 - Definitions.  

Code of Federal Regulations, 2011 CFR

...inherently buoyant material. (e) Inflation medium means any solid, liquid, or gas, that...means a model AK-1, adult PFD; model CKM-1, child medium PFD; or model CKS-2, child small PFD, meeting the...

2011-10-01

363

Measurements and implications of vortex motions using two flow-visualization techniques  

NASA Astrophysics Data System (ADS)

The present comparative study of two different, but complementary flow-visualization techniques, which yield different interpretations of vortex-migration distance and lifetime, gives attention to the difficulty of determining vortex evolution and lifetime from flow-visualization measurements. The techniques involved the release of a fluorescent dye and of neutrally buoyant particles in a water-filled towing tank. Vortices are found to migrate farther, and last longer, when visualized with neutrally buoyant particles rather than with dyes.

Delisi, Donald P.; Greene, George C.

1990-11-01

364

Physicochemical characterization of cyanophage SM2  

Microsoft Academic Search

Cyanophage SM-2 which infects two unicellular cyanobacteria, Synechococcus elongatus UTEX 563 and Microcystis aeruginosa NRC-1 (Synechococcus sp. NRC-1) UTEX 1937 has a buoyant density of 1.483 g\\/cm3, a DNA buoyant density of 1.729 g\\/cm3 and a guanine + cytosine (G+C) content of 69–70%. The protein patterns of cyanophage SM-2 particles showed 11 bands, as determined by polyacrylamide gel electrophoresis, with

Randall Benson; Eugene Martin

1984-01-01

365

Nonlinear traveling waves in a multilayer system.  

PubMed

The nonlinear convective regimes in multilayer system air-ethylene glycol-fluorinert FC75 heated from below under the joint action of buoyant and thermocapillary mechanisms of instability are investigated. The periodic boundary conditions on the lateral boundaries are considered. It is found that the competition of both mechanisms of instability may lead to the development of specific types of flow: buoyant-thermocapillary traveling wave and pulsating traveling wave. PMID:19518568

Simanovskii, Ilya B

2009-05-26

366

Isolation of Circular DNA from a Mitochondrial Fraction from Yeast  

Microsoft Academic Search

Breakage and fractionation of respiratory competent yeast in the presence of ethidium bromide, and subsequent centrifugation of a detergent lysate of the mitochondrial fraction by the dye-buoyant-density technique, results in the isolation of closed-circular DNA. After removal of bound dye, this DNA has two components when analyzed by equilibrium buoyant density in the analytical ultracentrifuge. A minor component has a

G. D. Clark-Walker

1972-01-01

367

Spreading and convective dissolution of carbon dioxide in vertically confined, horizontal aquifers  

NASA Astrophysics Data System (ADS)

Injection of carbon dioxide (CO2) into saline aquifers is a promising tool for reducing anthropogenic CO2 emissions. At reservoir conditions, the injected CO2 is buoyant relative to the ambient groundwater. The buoyant plume of CO2 rises toward the top of the aquifer and spreads laterally as a gravity current, presenting the risk of leakage into shallower formations via a fracture or fault. In contrast, the mixture that forms as the CO2 dissolves into the ambient water is denser than the water and sinks, driving a convective process that enhances CO2dissolution and promotes stable long-term storage. Motivated by this problem, we study convective dissolution from a buoyant gravity current as it spreads along the top of a vertically confined, horizontal aquifer. We conduct laboratory experiments with analog fluids (water and a mixture of methanol and ethylene glycol) and compare the experimental results with simple theoretical models. Since the aquifer has a finite thickness, dissolved buoyant fluid accumulates along the bottom of the aquifer, and this mixture spreads laterally as a dense gravity current. When dissolved buoyant fluid accumulates slowly, our experiments show that the spreading of the buoyant current is characterized by a parabola-like advance and retreat of its leading edge. When dissolved buoyant fluid accumulates quickly, the retreat of the leading edge slows as further dissolution is controlled by the slumping of the dense gravity current. We show that simple theoretical models predict this behavior in both limits, where the accumulation of dissolved buoyant fluid is either negligible or dominant. Finally, we apply one of these models to a plume of CO2 in a saline aquifer. We show that the accumulation of dissolved CO2 in the water can increase the maximum extent of the CO2 plume by several fold and the lifetime of the CO2 plume by several orders of magnitude.

MacMinn, Christopher W.; Neufeld, Jerome A.; Hesse, Marc A.; Huppert, Herbert E.

2012-11-01

368

Particle geochemistry in the Rainbow hydrothermal plume, Mid-Atlantic Ridge  

NASA Astrophysics Data System (ADS)

We report the analysis of 18 large volume (500-1500 L) in situ filtered samples of particulate material from the largest hydrothermal plume on the Mid-Atlantic Ridge, overlying the ultramafic-hosted Rainbow hydrothermal field at 36° 14'N. Measured particulate iron concentrations reach 614 nM. High concentrations of particulate Fe oxyhydroxides result from the extremely high Fe concentration (˜24 mM) and Fe/H 2S ratio (˜24) of the vent fluids, and persist to at least 10 km away from the vent site due to the advection of plume material with the ambient along-axis flow. Two of the nine pairs of pump deployments appear to have intercepted the buoyant or otherwise very young portion of the hydrothermal plume. These samples are characterized by anomalously (compared to neutrally buoyant plume samples) high concentrations of Mg, U, and chalcophile elements, and low concentrations of Mn, Ca, V, Y, and the rare earth elements (REE). Within the neutrally buoyant plume, elemental distributions are largely consistent with previously observed behaviors: preferential removal of chalcophile elements, conservative behavior of oxyanions (P, V, and U), and continuous scavenging of Y and the REE. This consistency is particularly significant in light of the underlying differences in fluid chemistry between Rainbow and other studied sites. Chalcophile elements are preferentially removed from the plume in the order Cd>Zn>Co>Cu. Phosphorus/iron and vanadium/iron ratios for the neutrally buoyant plume are consistent with global trends with respect to the concentration of dissolved phosphate in ambient seawater. Comparison of buoyant and neutrally buoyant plume ratios with data from hydrothermal sediments underlying the Rainbow plume (Cave et al., 2002) indicates, however, that while P/Fe ratios are indeed constant V/Fe ratios increase progressively from early stage plume particles to sediments. REE distributions in the buoyant and neutrally buoyant plume appear most consistent with a continuous scavenging process during dispersion through the water column.

Edmonds, Henrietta N.; German, Christopher R.

2004-02-01

369

The stability of buoyancy-driven coastal currents  

Microsoft Academic Search

Griffiths, R.W. and Linden, P.F., 1981. The stability of buoyancy-driven coastal currents. Dyn. Atmos. Oceans, 5: 281--306. Buoyancy-driven boundary currents were generated in the laboratory by releasing buoyant fluid from a source adjacent to a vertical boundary in a rotating container. The boundary removed the Coriolis force parallel to it, allowing the buoyant fluid to spread in a current along

R. W. GRIFFITHS; P. F. LINDEN

1981-01-01

370

Vertical reser storage offered by new semi  

SciTech Connect

A semisubmersible drilling rig concept is described. The rig utilizes a large buoyant center caisson and specially shaped lower hulls to improve the vessel's motion characteristics. The center caisson serves as vertical storage for riser joints and one of the units blowout preventer stacks. By use of this buoyant storage area, the vessel's center of gravity is lowered and the upper deck is cleared for extra working space.

Not Available

1985-01-01

371

Distribution and composition of hydrothermal plume particles from the ASHES vent field at Axial Volcano, Juan de Fuca Ridge. [Axial Seamount Hydrothermal Emission Study  

SciTech Connect

In 1986 and 1987, buoyant and neutrally buoyant hydrothermal plume particles from the ASHES vent field within Axial Volcano were sampled to study their variations in composition with height above the seafloor. Individual mineral phases were identified using standard X ray diffraction procedures. Elemental composition and particle morphologies were determined by X ray fluorescence spectrometry and scanning electron microscopy/X ray energy spectrometry techniques. The vent particles were primarily composed of sphalerite, anhydrite, pyrite, pyrrhotite, chalcopyrite, barite, hydrous iron oxides, and amorphous silica. Grain size analyses of buoyant plume particles showed rapid particle growth in the first few centimeters above the vent orifice, followed by differential sedimentation of the larger sulfide and sulfate minerals out of the buoyant plume. The neutrally buoyant plume consisted of a lower plume, which was highly enriched in Fe, S, Zn, and Cu, and an upper plume, which was highly enriched in Fe and Mn. The upper plume was enriched in Fe and Mn oxyhydroxide particles, and the lower plume was enriched in suspended sulfide particles in addition to the Fe and Mn oxyhydroxide particles. The chemical data for the water column particles indicate that chemical scavenging and differential sedimentation processes are major factors controlling the composition of the dispersing hydrothermal particles. Short-term sediment trap experiments indicate that the fallout from the ASHES vent field is not as large as some of the other vent fields on the Juan de Fuca Ridge.

Feely, R.A.; Geiselman, T.L.; Baker, E.T.; Massoth, G.J. (NOAA, Seattle, WA (United States)); Hammond, S.R. (NOAA, Newport, OR (United States))

1990-08-10

372

Can a sheet-like low-velocity region form an elongated Large Igneous Province?  

NASA Astrophysics Data System (ADS)

High-resolution tomography of the lower mantle has revealed the existence of another chemically distinct region with low-velocity and a sheet-like structure beneath the western Pacific. On the other hand, Large Igneous Provinces (LIPs) sometimes have elongated shapes. If a sheet-like upwelling reaches the Earth's surface while maintaining its shape, an elongated LIP may form. In order to test this hypothesis, we perform a series of experiments and investigate the stability of a buoyant sheet. The experimental results show that the buoyant fluid accumulates at the top of the sheet to form a buoyant cylinder. The gravitational instability divides the cylinder into several plume heads. We develop a model to explain the growth of the buoyant cylinder and the time scale until instability begins. Our model shows that a thin sheet-like upwelling with a width of 200 km, a small density difference from the ambient mantle, 10 kg m-3, and a high supply rate of buoyant fluid, 0.1 m yr-1, can reach the Earth's surface while maintaining its shape. We thus infer that LIPs with an elongated shape can be generated by sheet-like upwellings. The width of the observed sheet-like low-velocity region beneath the western Pacific is 500 km and is marginally sufficient to form an elongated LIP.

Namiki, Atsuko; Sueyoshi, Kenta; Takeuchi, Nozomu

2013-08-01

373

Wave energy desalinization  

SciTech Connect

A device for producing fresh water from salt sea water by utilizing the hydrodynamic energy of waves, comprising a buoyant platform; means for mooring the platform; a pump connected to the mooring means; a reservoir for pressurized sea water; a desalination system for extracting fresh water from the sea water; hydraulic flow control means for causing the pump to pump sea water into the sea water reservoir, as motion of the buoyant platform is produced due to the passing of waves beneath it; measuring means for measuring parameters of the sea adjacent the buoyant platform; and a control device connected to control the pressure in the sea water reservoir and the flow of sea water from the reservoir through the desalination system in response to the parameters of the sea.

Hopfe, H.H.

1982-06-22

374

The water entry of decelerating spheres  

NASA Astrophysics Data System (ADS)

We present the results of a combined experimental and theoretical investigation of the vertical impact of low-density spheres on a water surface. Particular attention is given to characterizing the sphere dynamics and the influence of its deceleration on the shape of the resulting air cavity. A theoretical model is developed which yields simple expressions for the pinch-off time and depth, as well as the volume of air entrained by the sphere. Theoretical predictions compare favorably with our experimental observations, and allow us to rationalize the form of water-entry cavities resulting from the impact of buoyant and nearly buoyant spheres.

Aristoff, Jeffrey M.; Truscott, Tadd T.; Techet, Alexandra H.; Bush, John W. M.

2010-03-01

375

Target-strength studies on Atlantic cod (Gadus morhua) in Newfoundland waters  

Microsoft Academic Search

(standardized to cod) was 1.5 dB higher at night when cod were up to 140 m oV bottom. Night-time TS did not diVer from theex situTS-daytime TS was significantly lower by 1.5 dB. Our findings are consistent with cod being neutrally buoyant oV bottom (night) and negatively buoyant nearer bottom in the day-time. Pooled neutrally buoyantin situandex situTS (38 kHz)

G. A. Rose; D. R. Porter

1996-01-01

376

Deep water riser system for offshore drilling  

SciTech Connect

A buoyant riser system for use in a deep water offshore drilling environment is anchored by a system of compliant guys below the active weather zone of the sea. A controllably buoyant housing of the system is submerged at a depth that is readily accessible to divers and includes a blow-out preventer (BOP) from which a suspended sub-riser leads to a well bore to which the sub-riser is coupled. Above the housing, a riser suspended from a floating drill rig is coupled to the BOP thereby communicating the drill rig directly with the well bore for drilling and well completion operations.

Potts, H.L.

1984-05-15

377

Pneumatic riser tensioner  

SciTech Connect

An apparatus is described for supporting an elongate element from a buoyant offshore structure, comprising; a mounting frame adapted to be affixed to the buoyant offshore structure; a support connector adapted to be attached to an upper portion of the elongate element; a bellows having an expandable interior chamber, a first end affixed to the support connector and a second end affixed to the mounting frame; and a valve means connected to the chamber whereby gas may be introduced into or removed from expandable chamber.

Stanton, P.N.; Cook, M.F.

1989-02-28

378

Dynamics of anchored flux tubes in the convection zone. I - Details of the model  

NASA Astrophysics Data System (ADS)

A model for the emergence of buoyant segments of magnetic flux tubes whose ends are still anchored in the stable layers below the convection zone is developed. This model is based on the thin flux tube approximation of Spruit. Several specific examples of buoyant flux tube evolution computed with the model are described. In particular, attention is given to an example of a flux tube which results in upflows as it emerges, in contrast to the downflows generally believed to accompany the Parker instability.

Chou, Dean-Yi; Fisher, George H.

1989-06-01

379

Different types of nonlinear convective oscillations in a multilayer system under the joint action of buoyancy and thermocapillary effect  

NASA Astrophysics Data System (ADS)

The nonlinear development of oscillatory instability under the joint action of buoyant and thermocapillary effects in a multilayer system, is investigated. The nonlinear convective regimes are studied by the finite difference method. Two different types of boundary conditions - periodic boundary conditions and rigid heat-insulated lateral walls, are considered. It is found that in the case of periodic boundary conditions, the competition of both mechanisms of instability may lead to the development of specific types of flow: buoyant-thermocapillary traveling wave and pulsating traveling wave. In the case of rigid heat-insulated boundaries, various types of nonlinear flows - symmetric and asymmetric oscillations, have been found.

Simanovskii, I. B.; Viviani, A.; Dubois, F.; -C., Legros J.

2011-02-01

380

Method of controlling displacement of propping agent in fracturing treatments  

SciTech Connect

A method of preventing overdisplacement of propping agent particles during well treatments to hydraulically induce a fracture in a subterranean formation wherein buoyant or neutrally buoyant ball sealers are incorporated in the trailing end portion of the fracturing fluid. The ball sealers seat on at least some of the well perforations in final stages of particle injection thereby causing the surface pumping pressure to increase, signaling the end of the treating operation. This minimizes proppant overdisplacement and provides for a fully packed fracture in the near wellbore region.

Erbstoesser, S.R.; Graham, R.L.

1983-12-20

381

Clinical development of Listeria monocytogenes-based immunotherapies.  

PubMed

Active immunotherapy targeting dendritic cells (DCs) has shown great promise in preclinical models and in human clinical trials for the treatment of malignant disease. Sipuleucel-T (Provenge, Dendreon, Seattle, WA), which consists of antigen-loaded dendritic cells (DCs), recently became the first targeted therapeutic cancer vaccine to be approved by the US Food and Drug Administration (FDA). However, ex vivo therapies such as Provenge have practical limitations and elicit an immune response with limited scope. By contrast, live-attenuated Listeria monocytogenes (Lm) naturally targets DCs in vivo and stimulates both innate and adaptive cellular immunity. Lm-based vaccines engineered to express cancer antigens have demonstrated striking efficacy in several animal models and have resulted in encouraging anecdotal survival benefit in early human clinical trials. Two different Lm-based vaccine platforms have advanced into phase II clinical trials in cervical and pancreatic cancer. Future Lm-based clinical vaccine candidates are expected to feature polyvalent antigen expression and to be used in combination with other immunotherapies or conventional therapies such as radiotherapy and chemotherapy to augment efficacy. PMID:22595054

Le, Dung T; Dubenksy, Thomas W; Brockstedt, Dirk G

2012-06-01

382

Adjuvants for cancer vaccines.  

PubMed

The recent FDA approval of sipuleucel-T (Provenge), a patient-specific immunotherapy for androgen-independent prostate cancer developed by Dendreon Corporation, has provided support for the concept of cellular immunotherapy as an approach to cancer treatment. Adjuvants are compounds that enhance the potency of the antigen-specific immune response and can be an essential component of an efficacious vaccine. Cervarix is a prophylactic vaccine against human papilloma virus (HPV) types 16 and 18, which can cause cervical cancer, and recently received approval from the FDA, due in part to the protective immunity it conferred against not only HPV types contained in the vaccine but in addition to oncogenic HPV strains that were not contained in the vaccine. Cervarix is formulated with MPL (monophosphoryl lipid A), a TLR-4 targeted adjuvant shown to promote immune response broadening. The recent FDA approvals of these pioneering vaccines are landmark events, and will likely usher in renewed interest and investment in the development of new therapeutic cancer vaccine candidates. In this review, we examine new molecularly defined adjuvants and formulations and its application to cancer vaccines under development. PMID:20488726

Dubensky, Thomas W; Reed, Steven G

2010-05-21

383

Sipuleucel-T for prostate cancer: the immunotherapy era has commenced.  

PubMed

The US FDA recently approved sipuleucel-T (Provenge(®), Dendreon, Inc., WA, USA) on the grounds of the results reported by a Phase III trial, which are presented and discussed in detail in this article. This study was conducted in 512 metastatic castration-resistant prostate cancer patients randomized in a 2:1 ratio to receive either active therapy or placebo. Although no difference in time to progression was observed, a survival advantage was achieved, with a statistically meaningful 4.1-month improvement in median survival in the active arm with respect to the placebo arm (25.8 vs 21.7 months). In view of its favorable toxicity profile and manageable route of administration, sipuleucel-T is the ideal agent to be combined with other standard treatments, which include hormonal, cytotoxic and biological agents, and radiotherapy. Sipuleucel-T opens exciting new paradigms for prostate cancer and increases the possibility of survival prolongation for men with this deadly disease. PMID:21166508

Buonerba, Carlo; Ferro, Matteo; Di Lorenzo, Giuseppe

2011-01-01

384

PROVENGE (Sipuleucel-T) in prostate cancer: the first FDA-approved therapeutic cancer vaccine.  

PubMed

Sipuleucel-T (PROVENGE; Dendreon) is the first therapeutic cancer vaccine to be approved by the U.S. Food and Drug Administration. In men who have metastatic castration-resistant prostate cancer with no or minimal symptoms, sipuleucel-T prolongs median survival by 4.1 months compared with results in those treated with placebo. At 3 years, the proportion of patients in the vaccine group who were alive was 50% higher than that in the control group (31.7% versus 21.7%, respectively). Sipuleucel-T, which is designed to elicit an immune response to prostatic acid phosphatase, uses the patient's own immune system to recognize and combat his cancer. Currently, no other agents are available that offer a survival benefit for this population of asymptomatic patients who have not been treated with chemotherapy, except for docetaxel (whose inherent toxicities often lead patients and physicians to delay administration until symptoms develop). Straightforward strategies to increase the efficacy of sipuleucel-T are likely to provide even greater benefit. The preclinical and clinical development of sipuleucel-T is reviewed, and approaches to enhance efficacy are considered herein. PMID:21471425

Cheever, Martin A; Higano, Celestia S

2011-04-06

385

Lessons from randomized phase III studies with active cancer immunotherapies--outcomes from the 2006 meeting of the Cancer Vaccine Consortium (CVC).  

PubMed

After years of effort to develop active cancer immunotherapies, seven candidate products achieved promising results in phase I/II studies that triggered phase III randomized studies. One candidate to date has received an approvable letter from the United States Food and Drug Administration (FDA), defining a clear path to licensure for sipuleucel-T (Provenge, Dendreon) within the next couple of years. The other phase III studies failed to achieve statistical criteria for some or all of the critical endpoints. Yet, there is widespread recognition that using a patient's own immune system to target and destroy cancer cells may offer an effective biological therapy with less toxicity than presently available anti-cancer therapies, and several candidates are still being evaluated in clinical studies. This review summarizes the lessons learned from these case studies, evaluates scientific, study design, and business factors that can affect study outcomes, identifies common challenges faced by sponsors developing these innovative therapies, and provides considerations for future study designs that may increase the likelihood of success. PMID:17916465

Finke, Lothar H; Wentworth, Kerry; Blumenstein, Brent; Rudolph, Natalie S; Levitsky, Hyam; Hoos, Axel

2007-09-27

386

Clinical Development of Listeria monocytogenes-Based Immunotherapies  

PubMed Central

Active immunotherapy targeting dendritic cells (DCs) has shown great promise in preclinical models and in human clinical trials for the treatment of malignant disease. Sipuleucel-T (Provenge, Dendreon, Seattle, WA), which consists of antigen-loaded dendritic cells (DCs), recently became the first targeted therapeutic cancer vaccine to be approved by the US Food and Drug Administration (FDA). However, ex vivo therapies such as Provenge have practical limitations and elicit an immune response with limited scope. By contrast, live-attenuated Listeria monocytogenes (Lm) naturally targets DCs in vivo and stimulates both innate and adaptive cellular immunity. Lm-based vaccines engineered to express cancer antigens have demonstrated striking efficacy in several animal models and have resulted in encouraging anecdotal survival benefit in early human clinical trials. Two different Lm-based vaccine platforms have advanced into phase II clinical trials in cervical and pancreatic cancer. Future Lm-based clinical vaccine candidates are expected to feature polyvalent antigen expression and to be used in combination with other immunotherapies or conventional therapies such as radiotherapy and chemotherapy to augment efficacy.

Le, Dung T.; Dubensky, Thomas W.; Brockstedt, Dirk G.

2013-01-01

387

An automatically profiling temperature sensor for upper ocean measurements  

Microsoft Academic Search

An automatically profiling buoy system has been developed for measuring temperature in the upper 50 meters of the ocean. Temperature and pressure sensors are housed in a profiling unit which is tethered to a support buoy on the surface via a neutrally buoyant electrical cable and air hose. An air bladder within the profiler causes the profiler to cycle between

C. Nelson; R. Chappell

1982-01-01

388

Direct Sampling of Entrainment Events in a Marine Stratocumulus Layer  

Microsoft Academic Search

Entrainment mixing and the stability of a marine stratocumulus layer are investigated using aircraft data gathered during the FIRE marine stratocumulus experiment. Direct measurement of entrainment events is accomplished through conditional sampling based on ozone mixing ratio. This enables the identification of evaporatively cooled, negatively buoyant events that could otherwise only be inferred by thermodynamic jump conditions at cloud top.

Siri Jodha S. Khalsa

1993-01-01

389

Resilience in Families with Children and Adult Members with Intellectual Disabilities: Tracing Elements of a Psycho-Social Model  

ERIC Educational Resources Information Center

|Aim: This paper seeks to illumine how families with children and adult members with intellectual disabilities manage to manifest a buoyant and durable capacity over time. It is therefore concerned centrally with the idea of resilience. Method: Drawing from diverse theoretical literatures from child development and protection and gerontology, the…

Grant, Gordon; Ramcharan, Paul; Flynn, Margaret

2007-01-01

390

Ice island structure and drilling method  

Microsoft Academic Search

An off-shore ice island structure for location over a submerged drill site in waters which normally freeze in winter. The structure includes a buoyant protective caisson which freezes in position over the drill site upon onset of winter. A barge floats on water kept unfrozen within the caisson, and is connected to the caisson so it can be swivelled generally

1984-01-01

391

The Effective Mass of a Ball in the Air  

ERIC Educational Resources Information Center

|The air surrounding a projectile affects the projectile's motion in three very different ways: the drag force, the buoyant force, and the added mass. The added mass is an increase in the projectile's inertia from the motion of the air around it. Here we experimentally measure the added mass of a spherical projectile in air. The results agree well…

Messer, J.; Pantaleone, J.

2010-01-01

392

Numerical simulation of transient hydroelastic response of a floating beam induced by landing loads  

Microsoft Academic Search

The dynamic response of a floating platform under the effects of impulsive and moving loads is of concern in various areas of engineering technology, such as floating airports, floating bridges and buoyant tunnels, among others. In the present work, the floating platform is simplified as a flexible beam floating in an infinite water domain. The water is assumed to be

Liu-chao Qiu

2007-01-01

393

A decadal record of underflows from a coastal river into the deep sea  

Microsoft Academic Search

Four periods of extreme turbidity were measured in Monterey Submarine Canyon over the past 12 yr. These turbid events oc- curred simultaneously with the four largest flood events of the nearby Salinas River. They filled the canyon with fresher, warmer, and, apparently, buoyant water that extended to depths below 1 km. The low-salinity signature must reflect underflow of the Sali-

Kenneth S. Johnson; Charles K. Paull; James P. Barry; Francisco P. Chavez

2001-01-01

394

A Study of the Interaction Between a Jet Flame and a Lateral Wall  

Microsoft Academic Search

The dynamic process of the interaction between a jet flame and a lateral wall is experimentally studied. The evolution of the outer buoyant vortices, which are involved in the jet flame bulge and flame tip-cutting phenomena, is found to play the central role in the flame-wall interaction process for low speed jet flames. The flame response as the lateral wall

YEI-CHIN CHAO; CHIH-YUNG WU

2000-01-01

395

46 CFR 35.03-15 - Shipboard stowage-TB/ALL.  

Code of Federal Regulations, 2011 CFR

... 2011-10-01 2011-10-01 false Shipboard stowage-TB/ALL. 35.03-15 Section 35.03-15 Shipping COAST...OPERATIONS Work Vests § 35.03-15 Shipboard stowageâTB/ALL. (a) The approved buoyant work vests shall be...

2011-10-01

396

46 CFR 35.03-15 - Shipboard stowage-TB/ALL.  

Code of Federal Regulations, 2012 CFR

... 2012-10-01 2012-10-01 false Shipboard stowage-TB/ALL. 35.03-15 Section 35.03-15 Shipping COAST...OPERATIONS Work Vests § 35.03-15 Shipboard stowageâTB/ALL. (a) The approved buoyant work vests shall be...

2012-10-01

397

Coal conversion defines route for gas-turbine development  

Microsoft Academic Search

The 1978 Gas Turbine Conference and exhibition was held in London against a background of a stagnant US utility market and a buoyant European industry taking orders from the Middle East. However, the prospect of coal-derived fuels in the future is keeping US development plans alive. There is interest in getting higher efficiency through combined-cycle developments and the installation of

N. Jenkins; M. Swiss

1978-01-01

398

Disengaged and Disaffected Young People: Surviving the System  

ERIC Educational Resources Information Center

|There are counter-narratives of youth as at risk and as buoyant and agentive. The article maps the conceptual terrain concerning resilience, well-being, buoyancy, enjoyment and happiness and selects factors related to the successful navigation of schooling. It analyses data from a subset of a national data set, from 65 young people considered to…

Lumby, Jacky

2012-01-01

399

RELATING ERROR BOUNDS FOR MAXIMUM CONCENTRATION ESTIMATES TO DIFFUSION METEOROLOGY UNCERTAINTY (JOURNAL VERSION)  

EPA Science Inventory

The paper relates the magnitude of the error bounds of data, used as inputs to a Gaussian dispersion model, to the magnitude of the error bounds of the model output. The research addresses the uncertainty in estimating the maximum concentrations from elevated buoyant sources duri...

400

A Plume Rise Model Compared with Observations  

Microsoft Academic Search

Dimensional arguments are used to predict plume rise for buoyant plumes in both stable and neutral air, for both calm and windy conditions. Dominant terms are assumed to be windpseed ?, “buoyancy flux” F (proportional to heat efflux), and a stability parameter s (proportional to potential temperature gradient). Observations presented support the dimensional analysis predictions, except that for final rise

Gary A. Briggs

1965-01-01

401

Solidification of an alloy cooled from above Part 1. Equilibrium growth  

Microsoft Academic Search

The interaction between the solidification and convection that occurs when a melt is cooled from above is investigated in a series of three papers. In these papers we consider a two-component melt that partially solidifies to leave a buoyant residual fluid. The solid forms a mushy layer of dendritic crystals, the interstices of which accommodate the residual fluid. The heat

ROSS C. KERR; ANDREW W. M. GRAE; WORSTER' S; HERBERT E. HUPPERT

402

Solidification of an alloy cooled from above. Part 3. Compositional stratification within the solid  

Microsoft Academic Search

This is the third of a series of papers which investigates the evolution of a binary alloy that is cooled from above and releases buoyant residual fluid as one component of the alloy is preferentially incorporated within the solid. This paper focuses on the compositional zonation that is produced when the melt is completely solidified. Parts 1 and 2 considered

Ross C. Kerr; Andrew W. Woods; M. Grae Worster; Herbert E. Huppert

1990-01-01

403

Fluid dynamics in explosive volcanic vents and craters  

Microsoft Academic Search

Explosive volcanic jets can transition to buoyant plumes or collapse to form pyroclastic density currents depending on their ability to entrain and heat the ambient air. Recent one-dimensional (1D) analysis shows that fluid acceleration through volcanic vents and craters changes the velocity and pressures within these jets sufficiently enough to be a first order control on plume dimensions and therefore

Darcy Ogden

404

MODELING GRAVITY EFFECT ON DIFFUSION FLAMES STABILIZED AROUND A CYLINDRICAL WICK SATURATED WITH LIQUID FUEL  

Microsoft Academic Search

The familiar flames from candles and oil lamps are representative examples of wick-stabilized diffusion flames. The shape and burning characteristics of these flames depend strongly on gravity-induced buoyant flows. To obtain a better understanding of the gravity effect, a diffusion flame model has been formulated and numerically solved. In the computation, gravity is treated as a parameter, spanning from zero

AMMAR ALSAIRAFI; SHIH-TUEN LEE; JAMES S. TIEN

2004-01-01

405

Numerical investigation of thermocapillary flow around a bubble  

Microsoft Academic Search

The thermocapillary flow induced by a gas bubble in a Newtonian liquid layer subjected to a stable temperature stratification is investigated. This flow is analyzed for a special configuration when the surface tension and buoyant forces oppose one another. The driving mechanism is the surface tension gradient related to the Marangoni number whereas the stabilizing effects are the viscous and

P. Arlabosse; N. Lock; M. Medale; M. Jaeger

1999-01-01

406

46 CFR 180.72 - Personal flotation devices carried in addition to life jackets.  

Code of Federal Regulations, 2010 CFR

...jackets and must not be substituted for the approved life jackets required to be worn during drills and emergencies. (b) Wearable marine buoyant devices that include âski vests,â âboating vests,â and âfishing vests,â approved in accordance...

2010-10-01

407

46 CFR 164.019-3 - Definitions.  

Code of Federal Regulations, 2011 CFR

... III. 4B IV (all Ring Buoys). 4BC IV (Buoyant Cushions). 4RB IV (Recreational Ring Buoys only). 5 Wearable Type V (intended use must be specified). 5H V (Hybrid). 5R V (Recreational Style). 5SB V (Sailboard...

2011-10-01

408

Revisiting Carbon Flux Through the Ocean's Twilight Zone  

Microsoft Academic Search

The oceanic biological pump drives sequestration of carbon dioxide in the deep sea via sinking particles. Rapid biological consumption and remineralization of carbon in the ``twilight zone'' (depths between the euphotic zone and 1000 meters) reduce the efficiency of sequestration. By using neutrally buoyant sediment traps to sample this chronically understudied realm, we measured a transfer efficiency of sinking particulate

Ken O. Buesseler; Carl H. Lamborg; Philip W. Boyd; Phoebe J. Lam; Thomas W. Trull; Robert R. Bidigare; James K. B. Bishop; Karen L. Casciotti; Frank Dehairs; Marc Elskens; Makio Honda; David M. Karl; David A. Siegel; Mary W. Silver; Deborah K. Steinberg; Jim Valdes; Benjamin Van Mooy; Stephanie Wilson

2007-01-01

409

Peat bog restoration by floating raft formation: the effects of groundwater and peat quality  

Microsoft Academic Search

Summary 1. A prerequisite for the restoration of desiccated bog remnants is rewetting the peat surface. Frequently in Europe, extensive areas are flooded in order to maximize water retention, and growth of peat mosses is often observed in the shallow zones. In deeper waters, regeneration appears to depend on whether residual peat will become buoyant and form floating rafts. 2.

Alfons J. P. Smolders; Hilde B. M. Tomassen; Leon P. M. Lamers; Bart P. Lomans; Jan G. M. Roelofs

2002-01-01

410

Recommendations for research in geotechnical engineering for Tension Leg Platforms  

Microsoft Academic Search

The Tension Leg Platform (TLP) is a buoyant, compliant structural system designed for drilling and producing oil and gas in deep water. The unique vertical mooring system of the TLP imposes a sustained uplift load on the platform's foundations; cyclic loads caused by environmental forces can be as large as the static uplift load. Deep water and the unusual type

Prindle

1985-01-01

411

A Critical Examination of the Relationship between Emotional Intelligence and Transformational Leadership  

Microsoft Academic Search

abstract The buoyant research interest in the constructs emotional intelligence (EI) and transformational leadership (TFL) is a testament to the crucial role of emotional skills at work. EI is often described as an antecedent of TFL, and several empirical studies report a positive relationship between these variables. On closer inspection, however, there may be methodological factors, such as common method

Dirk Lindebaum; Susan Cartwright

2010-01-01

412

Infectious Hypodermal and Hematopoietic Necrosis Virus of Shrimp Is Related to Mosquito Brevidensoviruses  

Microsoft Academic Search

We purified and sequenced infectious hypodermal and hematopoietic necrosis virus (IHHNV), a small DNA virus of shrimp, from wild Penaeus stylirostris. The virion has a buoyant density of 1.45 as determined by cesium chloride gradient. Analysis of 3873 nucleotides of the viral genome revealed three large open reading frames (ORFs) and parts of the noncoding termini of the viral genome.

Hiroko Shike; Arun K. Dhar; Jane C. Burns; Chisato Shimizu; Françoise X. Jousset; Kurt R. Klimpel; Max Bergoin

2000-01-01

413

Feasibility studies of in-situ coal gasification in the Warrior coal field. Quarterly report  

Microsoft Academic Search

Laboratory studies on a research combustor were used in an attempt to determine the length of oxidation and reduction zones. Unfortunately the buoyant effects of the heated gases caused the burn to proceed along the upper portion of the horizontal combustor. This made the interpretation of uncertain value. Methods of measuring the thermal conductivity and chemical reactivity of coke are

G. W. Douglas; M. D. McKinley

1979-01-01

414

An axisymmetric meniscus converges particles for microscopy.  

PubMed

Capillary rise on a tapered cylindrical rod creates a static axisymmetric meniscus that quantitatively attracts buoyant particles into a single microscopic field of view, providing a new method for small particle microscopy. This approach simplifies the visualization of micrometre-sized particles, such as pollen and parasite eggs, and has potential utility in remote location monitoring and clinical diagnosis. PMID:21801178

Sowerby, S J; Mirams, G J; Hill, P C; Paulin, M G

2011-08-01

415

Stirring and structure in mantle starting plumes  

Microsoft Academic Search

Simple arguments show that ascending thermal plumes will entrain their surroundings as the result of coupling between conduction of heat and laminar stirring driven by the plume motion. In the initial stages of ascent of a plume fed by a continuous buoyancy flux (a starting plume) the plume consists of a large buoyant head followed by a narrow vertical conduit.

Ross W. Griffiths; Ian H. Campbell

1990-01-01

416

A modeling study on steady-state and transverse dynamic motion of a towed array system  

Microsoft Academic Search

A numerical technique for mathematically modeling the steady-state and transverse dynamic motion of an underwater towed sonar array is presented. The transverse vibration response of the array is modeled using the finite difference method; the array itself is assumed to be nonneutrally buoyant and possesses a complex modulus and hence inherent damping. The results obtained from this model should provide

Chuan Lee

1978-01-01

417

Moving mass control for underwater vehicles  

Microsoft Academic Search

We present two reduced-dimensional, noncanonical Hamiltonian models for a neutrally buoyant underwater vehicle coupled to an internal moving mass. It is expected that these models will be useful in designing nonlinear control laws for underwater gliders as well as for spacecraft, atmospheric re-entry vehicles, and other vehicles which use internal moving mass actuators. To illustrate, we investigate stability of a

C. A. Woolsey; N. E. Leonard

2002-01-01

418

Size Segregation of Granular Materials  

Microsoft Academic Search

Segregation of granular materials due to size difference while flowing\\/energized is a very well known but poorly understood phenomena. Despite of some good understanding of the mechanism of size segregation, predictive models for size segregation are not available. Size segregation of binary granular mixtures flowing over inclined plane is studied by means of DEM simulations. Buoyant force acting on trace

Anurag Tripathi; D. V. Khakhar

2011-01-01

419

Active salinity choice and enhanced swimming endurance in 0 to 8-d-old larvae of diadromous gobies, including Sicydium punctatum (Pisces), in Dominica, West Indies  

Microsoft Academic Search

We studied the early life history of diadromous gobies in Dominica, West Indies, from May 1989 to May 1991, emphasising Sicydium punctatum Perugia. The transition of newly hatched larvae from upriver nest sites to the sea was studied in laboratory experiments. Newly hatched larvae are negatively buoyant but avoid settling to the bottom by active swimming during drift to the

K. N. I. Bell; J. A. Brown

1995-01-01

420

Optimal design of injection\\/extraction wells for the surface dissolution CO 2 storage strategy  

Microsoft Academic Search

Implementing geological carbon sequestration at a scale large enough to mitigate anthropogenic emissions will involve the injection of supercritical CO2 into deep saline aquifers. The principal technical risks associated with such injection are that (i) buoyant CO2 will migrate out of the storage formation; (ii) pressure elevation during injection will limit storage rates and\\/or fracture the storage formation; and (iii)

Lokendra Jain; Steven L. Bryant

2011-01-01

421

Plasmids in Methylomonas clara , a methylotrophic producer of single cell protein  

Microsoft Academic Search

Three single cell clones of the obligate methylotrophic bacterium Methylomonas clara originating from one fermentor culture were assayed for their DNA content. Apart from chromosomal DNA which showed no difference in the three strains, only two strains were found to carry plasmids with identical buoyant density and GC content but differing in contour length (12.4 µm and 4.9 µm respectively).

Ulf Stahl; Karl Esser

1982-01-01

422

Underwater turbine device with hinged collapsible blades  

SciTech Connect

A submersible turbine device which can be used in conjunction with a water wheel operated at water level, away from the submerged turbine device. The submersible turbine device comprises a turbine bed and a turbine wheel which comprises a central rotor and a plurality of turbine blades. A forward shield is positioned to permit current flow on the exposed turbine blades while shielding the opposite blades of the turbine wheel. The turbine blade comprises sections which are hinged in such a manner that they automatically extend when exposed to current flow for maximum drive and that they automatically fold for minimum resistance when travelling against water pressure. A supplementary turbine device comprises anchored, upwardly extending support means, a buoyant platform mounted to the anchored upwardly extending support means for floating at the water level, and a water wheel rotatably mounted in the buoyant platform. The upwardly extending support means is adapted to permit automatic vertical travel of the buoyant platform to adjust for changes in the water level and also to provide horizontal shifting of the water wheel to coordinate with the upwards and downwards movement of the buoyant platform.

Lee, E.M.

1983-05-17

423

Numerical modeling of ocean-ice interactions under Pine Island Bay's ice shelf  

Microsoft Academic Search

A two-dimensional numerical model is used to simulate the dynamics of buoyant, meltwater-rich plumes flowing beneath the ice shelf occupying much of Pine Island Bay, West Antarctica. Recent studies have shown that this ice shelf, along with all others fringing the Amundsen Sea, is thinning rapidly. In the model, both the Coriolis effect and subshelf topography are important in controlling

Antony J. Payne; Paul R. Holland; Andrew P. Shepherd; Ian C. Rutt; Adrian Jenkins; Ian Joughin

2007-01-01

424

On a Rotational Flow Disturbed by Gravity.  

National Technical Information Service (NTIS)

A rapidly rotating flow is examined that exhibits periodic vortex detachment. Specifically, the rotation/symmetry axis of a fluid-filled cylinder is set perpendicular to gravity. A free buoyant cylindrical float placed within the container is acted upon b...

H. P. Greenspan

1975-01-01

425

The formation and chemistry of low degree hydrous partial melt on top of the transition zone  

Microsoft Academic Search

There is some geophysical evidence for the presence of silicate melt on top of the 410 km seismic discontinuity. It has also been argued that the difference in the water storage capacity of upper mantle versus transition zone minerals may cause dehydration melting as material up-wells across the 410. Studies have proposed that hydrous partial melts may be neutrally buoyant

Daniel J. Frost; Mainak Mookherjee

2010-01-01

426

Dyke propagation and sill formation in a compressive tectonic environment  

Microsoft Academic Search

Sills could potentially form as a result of dykes modifying their trajectory in response to remote tectonic compression. Here, we use analogue experiments to investigate how a buoyant vertical dyke adjusts its trajectory to a compressive remote stress to form a sill, and over which vertical distance this sill formation does occur. Our investigation is restricted to an intrusion propagating

T. Menand; K. A. Daniels; P. Benghiat

2010-01-01

427

Cosmological Magnetohydrodynamic Simulations of Cluster Formation with Anisotropic Thermal Conduction  

Microsoft Academic Search

The intracluster medium (ICM) has been suggested to be buoyantly unstable in the presence of magnetic field and anisotropic thermal conduction. We perform first cosmological simulations of galaxy cluster formation that simultaneously include magnetic fields, radiative cooling, and anisotropic thermal conduction. In isolated and idealized cluster models, the magnetothermal instability (MTI) tends to reorient the magnetic fields radially whenever the

M. Ruszkowski; D. Lee; M. Brueggen; I. Parrish; S. Peng Oh; S. Peng

2011-01-01

428

Mortgage Equity Withdrawal in Australia and Britain: Towards a Wealth-fare State?  

Microsoft Academic Search

Across the decade to 2007, a combination of house price appreciation and relaxed credit constraints gave a boost to consumption through the mechanism of mortgage equity withdrawal (MEW). Arguably, this kept developed economies buoyant, even through periods of recession. This paper uses panel data on British and Australian homeowners to show that, notwithstanding its macro-economic effects, such borrowing has far-reaching

Sharon Parkinson; Beverley A. Searle; Susan J. Smith; Alice Stoakes; Gavin Wood

2009-01-01

429

Resolving the Confidence Crisis  

ERIC Educational Resources Information Center

As children approach adolescence, they often experience confusion and uncertainty as they attempt to appear more grown up than they really feel. Research on both girls and boys has documented that the buoyant self-confidence of younger children often gives way to self-consciousness as young adolescents become aware of the complexity and difficulty…

Apter, Terri

2006-01-01

430

Application of the finite element method to towed cable dynamics  

Microsoft Academic Search

This paper deals with towing an object through a fluid by means of a cable. For a slender, neutrally buoyant towbody, the planar configuration of the towed system is determined for steady motion and for time-dependent maneuvers of the towing vehicle. A formulation of the finite element method that applies to towed cable dynamics is presented including bending deformation and

Jeffrey Ketchman; Y. K. Lou

1975-01-01

431

Remote acoustic imaging of the plume from a submarine spring in an arctic fjord.  

PubMed

Acoustic backscatter observations at 200 kilohertz were made of the buoyant plume from a submarine spring at a depth of 47 meters in Cambridge Fiord, Baffin Island. Vertical velocities of up to 37 centimeters per second are inferred from the ascent rates of discrete scattering structures in the plume. PMID:17782423

Hay, A E

1984-09-14

432

Near-surface water temperatures in Doubtful Sound and response to natural and anthropogenic drivers  

Microsoft Academic Search

New Zealand fiords frequently feature a buoyant low-salinity layer (LSL) leading to unique biological communities on their rock walls. The LSL has previously been distinguished by its temperature, but we show this is not always reliable. We describe temporal and spatial patterns in water temperature in Doubtful Sound, and the influences of rainfall, wind, air temperature and the discharge from

E Goodwin; CD Cornelisen

2012-01-01

433

NEW DEVELOPMENT IN DISPERSION EXPERIMENTS AND MODELS FOR THE CONVECTIVE BOUNDARY LAYER  

EPA Science Inventory

We present recent experiments and modeling studies of dispersion in the convective boundary layer (CBL) with focus on highly-buoyant plumes that "loft" near the CBL top and resist downward mixing. Such plumes have been a significant problem in earlier dispersion models; they a...

434

Flow Visualization Studies in the Novacor Left Ventricular Assist System CRADA PC91-002, Final Report  

SciTech Connect

This paper discusses a series of experiments to visualize and measure flow fields in the Novacor left ventricular assist system (LVAS). The experiments utilize a multiple exposure, optical imaging technique called fluorescent image tracking velocimetry (FITV) to hack the motion of small, neutrally-buoyant particles in a flowing fluid.

Borovetz, H.S.; Shaffer, F.; Schaub, R.; Lund, L.; Woodard, J.

1999-01-01

435

Possible genotoxicity of melanin synthesis intermediates: Tyrosinase reaction products interact with DNA in vitro  

Microsoft Academic Search

The actual cellular target of the cytotoxic intermediates of melanin synthesis is not yet known. In the present paper it is shown that eukaryotic DNA binds in vitro to soluble reaction products of tyrosinase (EC 1.14.18.1) and is physically modified, as ascertained by the following criteria: (a) buoyant density in cesium chloride density gradients; (b) polyacrylamide gel electrophoresis: (c) deoxyribonuclease

M. Miranda; D. Botti; M. Cola

1984-01-01

436

33 CFR 143.405 - Equipment.  

Code of Federal Regulations, 2010 CFR

...CFR 160.171, or a buoyant suit meeting Supplement A of ANSI/UL-1123-1987 and approved under 46 CFR 160.053, for each...and Medical Aid at Seaâ, DHHS Publication No. (PHS) 84-2024, available from the Superintendent of Documents, U.S....

2009-07-01

437

33 CFR 143.405 - Equipment.  

Code of Federal Regulations, 2010 CFR

...CFR 160.171, or a buoyant suit meeting Supplement A of ANSI/UL-1123-1987 and approved under 46 CFR 160.053, for each...and Medical Aid at Seaâ, DHHS Publication No. (PHS) 84-2024, available from the Superintendent of Documents, U.S....

2010-07-01

438

Numerical modeling of flat-slab subduction in South America: the influence of thick overriding lithosphere  

Microsoft Academic Search

How and why normally dipping subduction zones evolve into flat subduction ones has been long debated. For example, it was suggested that slab flattening in South America results from subduction of buoyant aseismic ridges, however analogue and numerical models suggest that their dimensions are too small to induce flattening of such large slab segments. Here we note that in this

V. Manea; M. Perez-Gussinye; M. Manea

2010-01-01

439

46 CFR 26.30-1 - Approved unicellular plastic foam work vests.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Approved unicellular plastic foam work vests. 26.30-1 Section 26.30-1 Shipping...OPERATIONS Work Vest § 26.30-1 Approved unicellular plastic foam work vests. (a) Buoyant work vests carried under...

2011-10-01

440

46 CFR 28.510 - Definition of stability terms.  

Code of Federal Regulations, 2011 CFR

...occur. Flush deck means a continuous weather deck located at the uppermost sheer line...deck, or by a combination of partial weather deck and superstructure which is seaworthy...buoyant volume. Well deck means a weather deck fitted with solid bulwarks...

2011-10-01

441

46 CFR 28.510 - Definition of stability terms.  

Code of Federal Regulations, 2012 CFR

...occur. Flush deck means a continuous weather deck located at the uppermost sheer line...deck, or by a combination of partial weather deck and superstructure which is seaworthy...buoyant volume. Well deck means a weather deck fitted with solid bulwarks...

2012-10-01

442

Study of the Tagus estuarine plume using coupled hydro and biogeochemical models  

Microsoft Academic Search

Plumes of buoyant water produced by inflow from rivers and estuaries are common on the continental shelf. Buoyancy associated with estuarine waters is a key mediating factor in the transport and transformation of dissolved and particulate materials in coastal margins. The offshore displacement of the plume is influenced greatly by the local alongshore wind, which will tend to advect the

Nuno Vaz; Paulo C. Leitão; Manuela Juliano; Marcos Mateus; João. Miguel Dias; Ramiro Neves

2010-01-01

443

46 CFR 160.062-2 - Types.  

Code of Federal Regulations, 2011 CFR

...referred to under § 160.062-1(a)(1) are of the diaphram-spring plunger type, which releases a buoyant load under hydrostatic...under this subpart shall be designed and tested to operate with spring-tensioned gripes. Such gripes shall be considered as a...

2011-10-01

444

Velocity field measurements of a laminar starting plume  

Microsoft Academic Search

The region of buoyant fluid resulting from the initiation of heating of an infinite fluid is called the starting plume. Here, velocity field measurements of this flow pattern are presented for the first time. The measurements were carried out by processing digitized tracer particle path photographs. Similarity of the velocity field of the starting plume as it rises was found

J. Tanny; D. J. Shlien

1985-01-01

445

Numerical determination of the efficiency of entrainment in volcanic eruption columns  

Microsoft Academic Search

During explosive volcanic eruptions, a mixture of volcanic gas and pyroclasts is released from a volcanic vent with a large density relative to the atmospheric density. As the mixture rises, surrounding air is entrained owing to turbulence; the air expands as a result of heating from the hot pyroclasts, which can cause the mixture to become buoyant. Therefore, the efficiency

Y. J. Suzuki; T. Koyaguchi

2009-01-01

446

Dynamics of sediment subduction, melange formation, and prism accretion  

Microsoft Academic Search

The descending plate and overriding block in a subduction zone are analogous to the guide surface and slide block in a slipper bearing, and subducted sediment is analogous to the lubricant. Subduction is more complex and varied, however, because the overriding block is not rigid, the sediment is buoyant, underplating can occur, and sediment supply can vary widely. A model

Ronald L. Shreve; Mark Cloos

1986-01-01

447

Algebraic stress modeling in a buoyancy controlled turbulent shear flow  

Microsoft Academic Search

The paper presents an application of the algebraic stress modeling (ASM) technique to the prediction of the flow in a turbulent round buoyant jet. In the ASM approach, algebraic formulas are obtained for the Reynolds stresses and for the components of the turbulent heat flux. In the model used here, transport equations are solved for the turbulence kinetic energy, its

F. Tamanini

1977-01-01

448

Measurement of turbulent Prandtl number in a round jet  

Microsoft Academic Search

A method which combines two non-intrusive imaging techniques, particle tracking velocimetry (PTV) and laser induced fluorescence (LIF), was used to make simultaneous measurements of velocity and concentration in a neutrally buoyant turbulent round jet. The measurements were made at two different Reynolds numbers, 360 and 4210, and a Schmidt number of 1930. The mean velocity, mean concentration, Reynolds stress, and

Kuang-An Chang; Edwin Cowen

2000-01-01

449

Arrested development in Xenopus laevis tadpoles: how size constrains metamorphosis  

Microsoft Academic Search

Xenopus laevis tadpoles that arrest development and remain as larvae for several years sometimes occur spontaneously in laboratory populations. These tadpoles cease development at an early hindlimb stage, but continue to grow and develop into grossly deformed giants. Giant tadpoles lack thyroid glands, and differ in morphology and behaviour from normal larvae. They are negatively buoyant, typically with small and

Irena Rot-Nikcevic; Richard J. Wassersug

2004-01-01

450

Abundance of fish and crustacean postlarvae on portable artificial seagrass units: daily sampling provides quantitative estimates of the settlement of new recruits  

Microsoft Academic Search

Artificial collectors and seagrass units have mainly provided qualitative samples of epifaunal abundance or have been difficult and time-consuming to sample. Consequently, they are useful for distinguishing temporal or spatial trends in abundance or they are deployed for several weeks and, as a result, the quantitative samples are cumulative. We developed a portable artificial seagrass unit (ASU) with buoyant plastic

R. A Kenyon; M. D. E Haywood; D. S Heales; N. R Loneragan; R. C Pendrey; D. J Vance

1999-01-01

451

Role of the Laboratory: Static Equilibrium  

NSDL National Science Digital Library

This activity from the PTRA Manual "The Role of the Laboratory in Teaching Introductory Physics" is a variation of the typical static laboratory activity, and includes a method of measuring buoyant force. See article "Static Equilibrium", by Jim Nelson in the December, 1985 issue of The Science Teacher.

Nelson, Jim; Nelson, Jane

2006-06-18

452

CHARACTERIZATION OF THE DNA OF A NONOCCLUDED BACULOVIRUS, HZ-1V  

EPA Science Inventory

The DNA of the nonoccluded baculovirus (Hz-1V) obtained from the IMC-Hz-1 cell line was characterized by physicochemical and restriction endonuclease techniques. Hz-1V DNA isolated from purified virus had buoyant densities of 1.58 and 1.54 g/ml in CsC1-ethidium bromide density gr...

453

Granular Fluid Biofilter Reversing.  

National Technical Information Service (NTIS)

A biological filter system has a bed of buoyant granules a portion of which extends above the surface of the fluid. The bed is disposed above the effluent outlet. Distributor and receiving means are provided by which the filter can be backwashed.

W. J. Hess M. C. Croker

1983-01-01

454

Evaluation of dilution models for the discharge of produced water into the Gulf of Mexico.  

National Technical Information Service (NTIS)

A study was performed to determine which of two mixing models (CORMIX1 or UM/PLUMES) was more appropriate for simulating the vertically downward discharge of negatively buoyant produced waters into a stratified ambient having a crossflow in Gulf of Mexico...

D. Tomasko

1993-01-01

455

Are marine plastic particles transport vectors for organic pollutants to the Arctic?  

Microsoft Academic Search

Plastic litter accounts for 50–80% of waste items stranded on beaches, floating on the ocean surface and lodged in the seabed. Organic pollutants can be absorbed onto plastic particles from sea water, attached to their surfaces or included in the plastic matrix as additives. Such chemicals may be transported to remote regions by buoyant plastics and ocean currents. We have

Christiane Zarfl; Michael Matthies

2010-01-01

456

Transient wind-driven upwelling in a submarine canyon: A process-oriented modeling study  

Microsoft Academic Search

A hydrodynamic model is employed to study flow near a submarine canyon during conditions of upwelling-favorable coastal winds. Findings reveal that up-canyon flow is the rapid geostrophic adjustment to barotropic pressure gradients establishing across the canyon. Stratification leads to the formation of a cyclonic eddy within the canyon, trapping neutrally buoyant matter, and limits the upwelling depth only when a

Jochen Kämpf

2006-01-01

457

Preparation of PCR samples from food by a rapid and simple centrifugation technique evaluated by detection of Escherichia coli O157:H7  

Microsoft Academic Search

A sample treatment method based on buoyant density centrifugation which separates bacteria from food, concentrates bacteria and removes PCR inhibitors is described. The method involves a one minute centrifugation of food homogenate layered over a gradient medium (Percoll® or BacXtractor™) in Eppendorf tubes, followed by a single wash step. The small scale of this treatment makes it possible to process

Roland Lindqvist

1997-01-01

458

46 CFR 26.30-1 - Approved unicellular plastic foam work vests.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Approved unicellular plastic foam work vests. 26.30-1 Section 26.30-1 Shipping...OPERATIONS Work Vest § 26.30-1 Approved unicellular plastic foam work vests. (a) Buoyant work vests carried under...

2012-10-01

459

BAROCLINIC MATHEMATICAL MODELING OF FRESH WATER PLUMES IN THE INTERACTION RIVER-SEA  

Microsoft Academic Search

The estuarine zone is an area of strong interaction between fresh and salty water. Dynamics in these areas is complex due to the interaction of the forcing mechanisms such as wind, tides, local coastal currents and river dis- charges. The difierence of density between fresh water and salted water causes the formation of the buoyant plumes which have been investigated

HERMILO RAMIREZ; ECTOR ALFONSO BARRIOS; CLEMENTE RODRIGUEZ CUEVAS

2005-01-01

460

The Effects of Fuel Sooting Tendency and the Flow on Flame Radiation in Luminous Turbulent Jet Flames  

Microsoft Academic Search

In this paper two observations are emphasized with regard to flame radiation in luminous turbulent jet flames: (a) the radiant fraction in turbulent buoyant jet flames is a weak function of the fuel sooting tendency as expressed by the laminar smoke-point heat release rate; and (b) moreover, for very sooty fuels, the radiant fraction saturates to a constant value which

M. A. DELICHATSIOS; L. Orloff; M. M. DELICHATSIOS

1992-01-01

461

Laboratory and numerical studies of subduction zone anisotropy and the structure of subducted lithosphere  

Microsoft Academic Search

The deep structure and fate of subducted slabs, as well as the development of upper mantle anisotropy in the vicinity of a subducting slab, are studied using laboratory experiments. Rigid plexiglas plates, whisker particles, and a fluid with temperature-dependent viscosity are used. Upper mantle anisotropy is also studied numerically. I determine experimentally the behavior of a cold, negatively buoyant, highly

James L. Buttles

1998-01-01

462

Reactive Transport Modelling of CO2 Storage in Saline Aquifers to Elucidate Fundamental Processes, Trapping Mechanisms, and Sequestration Partitioning  

Microsoft Academic Search

The ultimate fate of CO injected into saline aquifers for environmental isolation is governed by three interdependent yet conceptually distinct processes: CO migration as a buoyant immiscible fluid phase, direct chemical interaction of this rising plume with ambient saline waters, and its indirect chemical interaction with aquifer and cap-rock minerals through the aqueous wetting phase. Each process is directly linked

J. W. Johnson; J. J. Nitao; K. G. Knauss

2004-01-01

463

Two-phase gravity currents in geological CO2 storage  

Microsoft Academic Search

Geological carbon capture and storage, in which compressed CO2 is injected into deep saline aquifers for permanent storage, forms an integral part of CO2 mitigation strategies. At representative reservoir conditions CO2 is buoyant and may therefore leak into surface waters or the atmosphere. The leakage of CO2 back into the atmosphere may be prevented by the formation of disconnected immobile

J. A. Neufeld; M. Golding; M. A. Hesse; H. E. Huppert

2010-01-01

464

Apparatus for storing the energy of ocean waves  

Microsoft Academic Search

A system is described for manufacturing hydrogen gas which utilizes the energy of surface waves in a liquid, such as an ocean. The system first converts the energy of surface waves to mechanical energy by apparatus comprising a buoyant helical member mounted for rotation about an axis. The pitch of the helical member can be matched to the length of

Lapeyre

1983-01-01

465

Apparatus for storing the energy of ocean waves  

Microsoft Academic Search

A system is described for manufacturing hydrogen gas which utilizes the energy of surface waves in a liquid, such as an ocean. The system first converts the energy of surface waves to mechanical energy by apparatus comprising a buoyant helical member mounted for rotation about an axis. The pitch of the helical member can be matched to the length of

Lapeyre

1984-01-01

466

Characteristics of Transverse Mixing in Open-Channel Flows.  

National Technical Information Service (NTIS)

The transverse spreading of a plume generated by a point source in a uniform open-channel flow is investigated. A neutrally-buoyant tracer was injected continuously at ambient velocity through a small round source at a point within the flow. Tracer concen...

J. K. Okoye

1970-01-01

467

Is China \\  

Microsoft Academic Search

In the past few years, observers increasingly have pointed to China as a source of downward pressure on global prices. This paper evaluates the theoretical and empirical evidence bearing on the question of whether China's buoyant export growth has led to significant changes in the inflation performance of its trading partners. This evidence suggests that the impact of Chinese exports

Steven B. Kamin; Mario Marazzi; John W. Schindler

2004-01-01

468

The Impact of Chinese Exports on Global Import Prices &ast  

Microsoft Academic Search

AbstractThis paper evaluates the evidence bearing on the question of whether China's buoyant export growth has led to significant changes in the import prices, and thus inflation performance, of its trading partners. This evidence suggests that the impact of Chinese exports on global import prices has been, while non- negligible, fairly modest. We identify a statistically significant effect of US

Steven B. Kamin; Mario Marazzi; John W. Schindler

2006-01-01

469

Dynamics of pyroclastic density currents studied using scaled laboratory experiments  

NASA Astrophysics Data System (ADS)

We performed a set of scaled laboratory experiments to simulate pyroclastic density currents (PDCs) using dilute mixtures of warm talc powder in air. The experiments were designed to evaluate the effects of topography and bed roughness on current runout, buoyancy reversal and liftoff, and mass partitioning into buoyant plumes. The densimetric and thermal Richardson, Froude, Stokes, and settling numbers for our experiments match those of PDCs and the laboratory currents are fully turbulent, although the experiments have lower Reynolds numbers than PDCs, thus our experiments are dynamically similar to natural currents. Comparisons of currents traversing flat topography or encountering barriers shows that runout distance is not significantly reduced for currents that traverse barriers with height less than 1.5 times the current thickness, but currents do not pass taller barriers. Buoyancy reversals occur in most currents, resulting in liftoff and generation of a buoyant plume. Liftoff occurs near the maximum runout distance for currents traveling over flat topography, but is focused near or above barriers for currents that encounter barriers. Notably, plume formation above barriers can result in reversal of flow direction downstream of the obstruction as portions of the current flow back and feed the rising plume. Greater than half of the initial particle mass composing the density currents usually partitions into the buoyant plumes; that fraction is greater for currents that liftoff closer to the source, thus topographic barriers increase mass partitioning from currents into buoyant plumes.

Manga, M.; Andrews, B.

2011-12-01

470

Laboratory studies of pyroclastic flows that interact with topography  

NASA Astrophysics Data System (ADS)

We performed a set of scaled laboratory experiments to simulate pyroclastic density currents (PDCs) using dilute mixtures of warm talc powder in air. The experiments were designed to evaluate the effects of topography on current runout, buoyancy reversal and liftoff, and mass partitioning into buoyant plumes. The densimetric and thermal Richardson, Froude, Stokes, and settling numbers for our experiments match those of PDCs and the laboratory currents are fully turbulent, although the experiments have lower Reynolds numbers than PDCs, thus our experiments are dynamically similar to natural currents. Comparisons of currents traversing flat topography or encountering barriers shows that runout distance is not significantly reduced for currents that traverse barriers with height less than 1.5 times the current thickness, but currents do not pass taller barriers. Buoyancy reversals occur in most currents, resulting in liftoff and generation of a buoyant plume. Liftoff occurs near the maximum runout distance for currents traveling over flat topography, but is focused near or above barriers for currents that encounter barriers. Notably, plume formation above barriers can result in reversal of flow direction downstream of the obstruction as portions of the current flow back and feed the rising plume. Greater than half of the initial particle mass composing the density currents usually partitions into the buoyant plumes; that fraction is greater for currents that liftoff closer to the source, thus topographic barriers increase mass partitioning from currents into buoyant plumes.

Andrews, B.; Manga, M.

2012-04-01

471

Subduction of an Aseismic Ridge: Interseismic Deformation Above the Cocos Ridge, Costa Rica  

Microsoft Academic Search

Subduction of aseismic ridges, seamounts and thickened, buoyant oceanic crust often results in deformation of the overriding plate. The Cocos Ridge and sub parallel seamount chains have been subducting along the Middle America Trench (MAT) for >0.5 Ma, resulting in cessation of volcanism, uplift of the Talamanca Range, deformation of the outer fore arc and shortening in the fore arc

P. C. Lafemina; T. H. Dixon; S. Scwartz; M. Protti; V. Gonzalez

2005-01-01

472

Buoyancy Regulation by Hatchery and Wild Coho Salmon during the Transition from Freshwater to Marine Environments  

Microsoft Academic Search

One aspect of diadromy that has received little attention is buoyancy regulation in fish moving between freshwater and marine environments. Because of density differences between the two water types, fish must alter their whole-fish density (WFD) or they will become positively (float) or negatively (sink) buoyant as they change environments. This idea was first suggested over 80 year ago but

Laurie A. Weitkamp

2008-01-01

473

Oceanic transport of calcified eggs: taphonomic and biogeographic implications  

Microsoft Academic Search

Estimates of the temporal and spatial resolution of fossil egg assemblages are required to constrain the inferences that can logically be drawn during assemblage analysis. Consequently, understanding egg transport mechanisms is required before conclusions are developed. Bird eggs are buoyant during part of development and can float from near shore nests during high tides, storm surges, or flooding. Complete and

Thomas Evans

2012-01-01

474

Particle structure control in nanoparticle synthesis from the vapor phase  

Microsoft Academic Search

Nanostructured materials have generally been synthesized by condensation from the vapor phase in an inert carrier gas, most often in a buoyant plume above a hot vapor source. Particles form by homogeneous nucleation as the gases cool and grow by Brownian coagulation. Previous studies have shown that the size of the smallest structures is reduced with decreasing pressure, so most

Richard C. Flagan; Melissa M. Lunden

1995-01-01

475

46 CFR 160.060-1 - Incorporation by reference.  

Code of Federal Regulations, 2011 CFR

...MIL-W-530F-Webbing, Textile, Cotton, General Purpose, Natural or in Colors. (3) Federal Standards: No. 191-Textile Test Methods...Pattern) (b) Plans. The following plans, of the issue in effect on the date buoyant vests are manufacture, form a part of...

2011-10-01

476

Rise dynamics and relative ash distribution in vulcanian eruption plumes at Santiaguito Volcano, Guatemala, revealed using an ultraviolet imaging camera  

Microsoft Academic Search

Santiaguito Volcano, Guatemala, regularly produces small vulcanian eruption plumes which rise to heights of up to 2 km. A combined study using a novel UV camera coupled with classical analysis of the fluid dynamics of finite-volume buoyant releases (thermals) has been used to develop a detection algorithm for ground-based volcanic ash monitoring. Analysis of plume rise dynamics shows that vulcanian

Hiroko Yamamoto; I. Matthew Watson; Jeremy C. Phillips; Gregg J. Bluth

2008-01-01

477

46 CFR 160.073-15 - Tests.  

Code of Federal Regulations, 2011 CFR

... 2011-10-01 2011-10-01 false Tests. 160.073-15 Section 160.073-15...and Buoyant Apparatus § 160.073-15 Tests. (a) The manufacturer shall perform a tensile test on the first three links made from a...

2011-10-01

478

46 CFR 160.073-15 - Tests.  

Code of Federal Regulations, 2012 CFR

... 2012-10-01 2012-10-01 false Tests. 160.073-15 Section 160.073-15...and Buoyant Apparatus § 160.073-15 Tests. (a) The manufacturer shall perform a tensile test on the first three links made from a...

2012-10-01

479

Comments on ‘Accuracy of precipitation measurements for hydrologic modeling’ by Lee W. Larson and Eugene L. Peck  

Microsoft Academic Search

proportion of small buoyant drizzle particles than a cold front. In winter the shape of the snowflake is a function of the temperature at which the flake is formed, not the surface temperature [World Meteorological Organization, 1970], so again the flake buoyancy will be much different for warm frontal snow than for a cold front. Areas such as the prairies

D. Storr

1975-01-01

480

The role of oceanic plateau subduction in the Laramide orogeny  

Microsoft Academic Search

The cause of the Laramide phase of mountain building remains uncertain. Conceptual models implicate the subduction of either ocean ridges or conjugates of the buoyant Hess or Shatsky oceanic plateaux. Independent verification of these models has remained elusive, because the putative ridges or plateaux are no longer at the Earth's surface. Inverse convection models have identified two prominent seismic anomalies

Lijun Liu; Michael Gurnis; Maria Seton; Jason Saleeby; R. Dietmar Müller; Jennifer M. Jackson

2010-01-01

481

Sur un nuage. Perspectives 1999-2000 pour l'économie mondiale  

Microsoft Academic Search

[eng] Prospects for the world economy in 1999 and 2000 Division Economie internationale World growth is expected to strengthen in 2000 with the upturn in Asian emerging countries and some recovery in Russia and Eastern European countries. GDP growth was still buoyant in the US in 1999 and is expected to decelerate in 2000 under the effect of weaker increases

Division économie internationale

1999-01-01

482

On the structure and dynamics of stationary and rotating spherical diffusion flames  

Microsoft Academic Search

This dissertation research is concerned with diffusion flames generated by a porous spherical burner. It consists of two parts: the structure and extinction of weakly buoyant, nearly spherical, stationary flames, and the structure and dynamics of these flames in response to rotation of the burner in micro-gravity. In the first part of the investigation, normal-gravity experiments were conducted with nearly

Sean Won S. Yoo

2006-01-01

483

LOCAL VOLUME-AVERAGED EQUATIONS OF MOTION FOR SUSPENSIONS IN SECOND-ORDER FLUIDS  

Microsoft Academic Search

The local volume averages of the equations of motion as well as the appropriate boundary conditions are developed for a flowing suspension of non-neutrally buoyant, uniform spheres in an incompressible, weak, second-order fluid under conditions such that inertial effects can be neglected. These equations do not represent an asymptotic theory with respect to the volume fraction of solids. Higher order

ALFRED C. Li; JOHN C. SLATTERY

1989-01-01

484

Toxic Alexandrium blooms in the western Gulf of Maine: The plume advection hypothesis revisited  

Microsoft Academic Search

The plume advection hypothesis links blooms of the toxic dinoflagellate Alexandrium fundyensein the western Gulf of Maine (GOM) to a buoyant plume derived from river outflows. This hypothesis was examined with cruise and moored-instrument observations in 1993 when levels of paralytic shellfish poisoning (PSP) toxins were high, and in 1994 when toxicity was low. A coupled physical-biological model simulated hydrography

D. M. Anderson; B. A. Keafer; W. R. Geyer; R. P. Signell; T. C. Loder

2005-01-01

485

Velocity measurements in the field of an internal gravity wave by means of speckle photography  

Microsoft Academic Search

Speckle velocimetry with forward scattering has been applied to measure and visualize the two-dimensional velocity field in an internal gravity wave. The wave was produced by towing a cylinder in vertical direction, normal to its axis, through stratified salt water. Neutrally buoyant tracer particles whose density was matched with the density distribution of the stratification were uniformly distributed in the

U. Gärtner; U. Wernekinck; W. Merzkirch

1986-01-01

486

Sky Floater Challenge  

NSDL National Science Digital Library

In this design challenge activity, learners make a balloon hover at eye level for five seconds, and then make it move by creating air currents. The activity guide contains information for Educators on how to best facilitate the challenge as well as key vocabulary (buoyancy, neutrally buoyant, Newton's 1st Law, etc.). Two associated videos available for download help reinforce these concepts.

Wgbh

2009-01-01

487

Application of nontraditional processing methods to transitional and turbulent boundary layer flow-noise-induced signals  

Microsoft Academic Search

This research applies dynamical system methods (i.e., Chaos Theory) to the processing of time sequences of transitional and turbulent wall-pressures impinging on the face of station probes mounted along the wall of an axisymmetric body of revolution during a buoyant ascent from the bottom of a deep water test basin. It is demonstrated that the turbulent pressure fluctuations for this

Richard A. Katz; Thomas A. Galib; Joan Cembrola

1993-01-01

488

Mechanisms underlying transitional and turbulent boundary layer (TBL) flow-induced noise in underwater acoustics (II)  

Microsoft Academic Search

This research applies dynamical system methods (i.e., Chaos Theory) to the processing of time sequences of transitional and turbulent wall-pressures impinging on the face of starion probes mounted along the wall of an axisymmetric body of revolution during a buoyant ascent from the bottom of a deep water test basin It is demonstrated that the twbulent pressure fluctuations for this

R. A. KATZ; T. GALIB; J. CEMBROLA

1994-01-01

489

Near Field of Starting Plumes  

Microsoft Academic Search

Although steady jets and plumes have been studied extensively in the past, there is relatively little known about the initial stages of starting buoyant jets. The present investigation examined buoyancy-driven flows resulting from cylindrical containers w ith length to diameter ratios (L\\/D) between 2 and 13. Density ratios up to ten percent were utilized. A technique was developed to release

H. Johari; M. Gharib; D. Dabiri

1997-01-01

490

A comparative study of buoyancy duration in Carya aquatica, Carya illinoinensis, and Carya x lecontei seeds  

Technology Transfer Automated Retrieval System (TEKTRAN)

A characteristic of Carya species is that their seeds are buoyant. The different physical properties of Carya seeds, such as oil composition and air-filled cavities, may contribute to this buoyancy. Carya aquatica (water hickory) and Carya illinoinensis (pecan) trees are found along streams and riv...

491

29 CFR 1926.106 - Working over or near water.  

Code of Federal Regulations, 2013 CFR

...after each use, the buoyant work vests or life preservers shall be inspected for defects which would alter their strength or buoyancy. Defective units shall not be used. (c) Ring buoys with at least 90 feet of line shall be provided and readily...

2013-07-01

492

Dynamical properties of a buoyancy-driven coastal current  

Microsoft Academic Search

The outflow of buoyant waters from major estuaries affects the dynamics of inner continental shelves profoundly as lateral density gradients force an alongshore current. Often the Coriolis force causes the outflow to remain trapped near the coast. We observed one such current, the Delaware Coastal Current, on the inner shelf near the Delaware Estuary on the eastern seaboard of the

Andreas Münchow; Richard W. Garvine

1993-01-01

493

Effects of bubble coalescence and breakup on conduit dynamics  

Microsoft Academic Search

Volatiles play a central role in eruption behavior. The ability of an exsolved gas phase to move through, and escape from, ascending magma controls whether an eruption is explosive or effusive. In this study, we investigate the dynamics and interactions of gas bubbles as they rise in a conduit. We focus on the coalescence and breakup dynamics of buoyant bubbles

C. Huber; J. Dufek; A. Parmigiani; M. Manga

2008-01-01

494

The development of a hybrid advanced composite-syntactic foam structural component for use in undersea vehicles  

Microsoft Academic Search

This paper presents the progress of an ongoing program to develop a lightweight, highly buoyant structural member for open-frame, remotely operated vehicles (ROVs). The structural component is fabricated from advanced composite materials and syntactic foam. This unique hybrid member is intended for, but not limited to, underwater vehicles. The paper demonstrates that composite materials and syntactic foams can offer great

John B. Hinves; Craig D. Douglas

1993-01-01

495

Marine riser system with dual purpose lift and heave compensator mechanism  

Microsoft Academic Search

Apparatus for drilling a well at a location submerged below a body of water includes a buoyant foundation structure. The foundation structure is floatable on the surface of the body of water and is subject to vertical motion in response to waves and the like. A riser handling and tensioning mechanism is mounted to the foundation structure and is operable

S. B. Wetmore; J. F. McNary; A. Person

1979-01-01

496

Mission concepts for Venus surface investigation  

Microsoft Academic Search

Mission concepts for the in situ investigation of the Venus atmosphere and surface in the period following the VOIR mission are discussed. The science issues in Venus exploration and possible means of meeting the scientific objectives are considered, including global mapping, surface composition determination, atmospheric composition determination and surface-atmosphere interactions. Particular attention is then given to the feasibility of buoyant

S. J. Hoffman; H. Feingold; A. Friedlander

1981-01-01

497

Free and forced convection in Earth's upper mantle  

Microsoft Academic Search

Convective motion within Earth's upper mantle occurs as a combination of two primary modes: (1) buoyant upwelling due to the formation of gravitational instabilities at thermochemical boundary layers, and (2) passive flow associated with the divergence of lithospheric plates at mid-ocean ridges and their re-entry into the mantle at subduction zones. The first mode is driven by variations in density

Paul S. Hall

2003-01-01

498

Flame characteristics for fires in southern fuels  

Treesearch

Asheville, NC: USDA-Forest Service, Southeast Forest Experiment Station. ... Approximate solutions are used to express flame lengths, angles, heights, and tip velocities of ... controlled burns in southern fuels and with data from the literature. Keywords: Flame length, flame velocity, flame angle, fire intensity, buoyant flames.

499

Density variation amongst mid-ocean ridge basalts: Implications for magma mixing and the scarcity of primitive lavas  

Microsoft Academic Search

Densities calculated from glass compositions of observed mid-ocean ridge basalts show that the more primitive melts are likely to be buoyant in more evolved melts. Consideration of this and other physical properties indicates that convective mixing between most basaltic magmas occurs under intermittently turbulent to turbulent conditions (transitional Reynolds Numbers) accounting for the widespread occurrence of hybrid lavas. Hypothetical picritic

R. S. J. Sparks; P. Meyer; H. Sigurdsson

1980-01-01

500

Drag and lift forces on particles in a rotating flow  

Microsoft Academic Search

A freely rotating sphere in a solid-body rotating flow is experimentally investigated. When the sphere is buoyant, it reaches an equilibrium position from which drag and lift coefficients are determined over a wide range of particle Reynolds numbers (2 ? Re ? 1060). The wake behind the sphere is visualized and appears to deflect strongly when the sphere is close

J. J. Bluemink; D. Lohse; A. Prosperetti; L. VAN WIJNGAARDEN

2010-01-01