Sample records for dacs-sc dendreon buoyant

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

    PubMed

    2006-01-01

    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

  2. Buoyant Force

    NSDL National Science Digital Library

    Renae Garski, Bigfork High School, Bigfork, MN, based on an original activity from Science Workshop, p. 115

    This activity is a lab where students gather data on buoyant force and height of and object being submerged in two different types of fluids. The slope of the buoyant force and height is proportional to the density of the fluid. Students compare the densities of the fluids calculated with the actual densities.

  3. Buoyant plume calculations

    SciTech Connect

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

    1985-01-01

    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.

  4. Buoyant station mission comcepts for titan exploration

    NASA Technical Reports Server (NTRS)

    Friedlander, A. L.

    1985-01-01

    An advanced mission to this unique satellite of Saturn appropriate to the turn-of-the-century time period is described. The mission concept evolves about one or more buoyant stations (balloons and/or airship) operating at varying altitudes in Titan's atmosphere. An orbiter of Titan provides communications link support and accomplishes remote sensing science objectives. Use of buoyant stations are favored over a fixed site lander for two reasons: (1) adaptable to several possible surface physical states and topographies; and (2) capable of exploring both the atmosphere and surface with regional and possibly global mobility. Auxiliary payload concepts investigated include tethered packages and sounding rockets deployed from the buoyant station, and haze probes and surface penetrators deployed from the orbiter. The paper describes science objectives and payloads, propulsion system/mass delivery trades, balloon design requirements and deployment/motion characteristics, and communications link geometry and data characteristics.

  5. 1Preliminary Instability in a buoyant chemical

    E-print Network

    Treibergs, Andrejs

    1Preliminary Instability in a buoyant chemical front driven by curvature Andrejs Treibergs May 23, 2006 Abstract We consider a model of a curvature dependent chemical reaction along a circular interface is focussed by negative curvature. The strength of the curvature term determines in large part the stability

  6. 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...

  7. 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...

  8. BUOYANT ADVECTION OF GASES IN UNSATURATED SOIL

    PubMed Central

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

    2010-01-01

    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. PMID:20396624

  9. BUOYANT ADVECTION OF GASES IN UNSATURATED SOIL.

    PubMed

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

    1994-09-01

    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. PMID:20396624

  10. Neutrally buoyant bubbles used as flow tracers in air

    Microsoft Academic Search

    Michael F. Kerho; Michael B. Bragg

    1994-01-01

    Research has been performed to determine the accuracy of neutrally buoyant and near-neutrally-buoyant bubbles used as flow tracers in an incompressible potential flowfield. Experimental and computational results are presented to evaluate the quantitative accuracy of neutrally buoyant bubbles using a commercially available helium bubble generation system. A two-dimensional experiment was conducted to determine actual bubble trajectories in the stagnation region

  11. Buoyant sustained release granules based on chitosan.

    PubMed

    Inouye, K; Machida, Y; Sannan, T; Nagai, T

    1989-01-01

    Attempts to develop sustained release intragastric 'floating' granules based on chitosan are described, using chitosan of different degrees of deacetylation (chitosan H and L), in granular form or in laminated preparations. The granules were made from chitosan H (chitosan H granules), from a 1:1 mixture of chitosan H and L (1:1 mixture granules), from a 1:2 mixture of chitosan H and L (1:2 mixture granules), or from chitosan L (chitosan L granules). They were prepared by a method involving deacidification, had internal cavities, were immediately buoyant in both acidic and neutral fluids, and gave sustained release of prednisolone (used as a model drug). The laminated preparations, composed of a chitosan granule layer and a chitosan L membrane, were also immediately buoyant in the same fluids, and also provided sustained release of the model drug. The release properties were controlled by regulating the chitosan L content of the granules, or the chitosan L membrane thickness of the laminate. In an absorption study using beagle dogs, sustained drug absorption from these preparations was obtained. PMID:2775446

  12. Pinch-off and formation number of negatively buoyant jets

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

    Previous investigations of starting buoyant jets are extended towards negative buoyancy to address key issues in the formation processes. A series of large-eddy simulations (LES) is performed to identify whether an optimal vortex can be formed with negative buoyancy and if so what the corresponding formation number would be. The numerical code was previously validated for non-buoyant and positively buoyant jets and is further validated here for negatively buoyant jets using literature data on submerged fountains. Subsequently, jets with a range of negative buoyancies are simulated using source Reynolds numbers of 2000 < Re < 3000. A revised, directional form of Richardson number (Rid) is proposed to accommodate the entire range of buoyancy, with Rid > 0 for positively buoyant jets, Rid = 0 for non-buoyant jets, and Rid < 0 for negatively buoyant jets. Simulations identify two ranges of negative buoyancy. For weakly negatively buoyant starting jets (- 0.05 <˜ Rid < 0), the pinch-off and formation of an optimal starting vortex occur, and the corresponding formation number can be determined using a revised algorithm, catering to negative buoyancy, based on the observed step jump in the vortex ring's circulation. This algorithm suggests a continuation of the declining trend in formation number with declining Rid identified previously for positively buoyant jets. For strongly negatively buoyant jets (Rid < -0.05), the starting vortex falls back onto the stem after the initial roll-up for -2.0 <˜ Rid < -0.05, and the pinch-off process does not exist for Rid <˜ -2.0 with the starting vortex and stem connected at all time. A plot of time-varying vortex circulation and penetration for starting plumes with different Rid unifies our understanding of buoyant vortex dynamics.

  13. 46 CFR 160.010-5 - Buoyant apparatus with plastic foam buoyancy.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...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...

  14. 46 CFR 160.010-5 - Buoyant apparatus with plastic foam buoyancy.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 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...

  15. 46 CFR 160.010-5 - Buoyant apparatus with plastic foam buoyancy.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...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...

  16. 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...010-5 Buoyant apparatus with plastic foam buoyancy. (a) Buoyant apparatus with plastic foam buoyancy must have a plastic foam body with...

  17. 46 CFR 160.010-5 - Buoyant apparatus with plastic foam buoyancy.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...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...

  18. Baroclinic instability of a buoyant coastal current

    NASA Astrophysics Data System (ADS)

    Hetland, Robert

    2014-05-01

    Classic models of baroclinic instability, notably the Eady model, depend on the Rossby (or Richardson) number as the sole non-dimensional parameter. Inclusion of a sloping bottom requires an additional parameter, the slope Burger number, Bu = ?Nf-1, where ? is the bottom slope. Numerical simulations of the evolution of instabilities along the edge of a coastally trapped buoyant flow suggest that the slope may help to stabilize the flow when the deformation radius is similar to or larger than the with of the buoyant flow, that is, the flow is stable when the slope Burger number is larger than about 0.3. In unstable cases, Bu < 0.3, baroclinic instabilities in the flow cause the isopycnals to relax, thereby increasing the local Burger number until the critical condition, Bu ? 0.3, is met. At this point the instabilities no longer grow in time, preventing further offshore buoyancy flux by the eddies. This final state corresponds approximately to the case where the slope of the ground is similar to the slope of the mean isopycnal surfaces. The nonlinear, three-dimensional numerical simulations are in basic agreement with one-dimensional linear stability analysis, with a few key exceptions. Notably, numerical simulations suggest that cross-shelf buoyancy fluxes are strongest in within the bottom boundary layer, showing a similar pattern to continental shelf waves in the vertical structure of current and tracer variability. Idealized simulations show a marked similarity to instabilities along the Mississippi/Atchafalaya plume front, as seen in observations and realistic regional models. These eddies have been shown to be important in Lagrangian transport of surface particles, notably oil spill trajectory prediction, and create patchiness in bottom dissolved oxygen distributions during periods of summertime seasonal hypoxia.

  19. A turbulence model for buoyant flows based on vorticity generation.

    SciTech Connect

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

    2005-10-01

    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.

  20. Using buoyant mass to measure the growth of single cells

    E-print Network

    Godin, Michel

    We used a suspended microchannel resonator (SMR) combined with picoliter-scale microfluidic control to measure buoyant mass and determine the 'instantaneous' growth rates of individual cells. The SMR measures mass with ...

  1. Behavior of buoyant moist plumes in turbulent atmospheres

    E-print Network

    Hamza, Redouane

    1981-01-01

    A widely applicable computational model of buoyant moist plumes in turbulent atmospheres has been constructed. To achieve this a one dimensional Planetary Boundary Layer (P.B.L.) model has been developed to account for ...

  2. Large-eddy simulation of starting buoyant jets

    E-print Network

    Law, Adrian Wing-Keung

    A series of Large Eddy Simulations (LES) are performed to investigate the penetration of starting buoyant jets. The LES code is first validated by comparing simulation results with existing experimental data for both steady ...

  3. 46 CFR 160.010-6 - Capacity of buoyant apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...following methods: (1) Final buoyancy of the buoyant apparatus in Newtons...divided by 145 (divided by 32 if buoyancy is measured in pounds). The divisor must be changed to 180 (40 if buoyancy is measured in pounds) if the...

  4. 46 CFR 160.010-6 - Capacity of buoyant apparatus.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...following methods: (1) Final buoyancy of the buoyant apparatus in Newtons...divided by 145 (divided by 32 if buoyancy is measured in pounds). The divisor must be changed to 180 (40 if buoyancy is measured in pounds) if the...

  5. 46 CFR 160.010-6 - Capacity of buoyant apparatus.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...following methods: (1) Final buoyancy of the buoyant apparatus in Newtons...divided by 145 (divided by 32 if buoyancy is measured in pounds). The divisor must be changed to 180 (40 if buoyancy is measured in pounds) if the...

  6. 46 CFR 160.010-6 - Capacity of buoyant apparatus.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...following methods: (1) Final buoyancy of the buoyant apparatus in Newtons...divided by 145 (divided by 32 if buoyancy is measured in pounds). The divisor must be changed to 180 (40 if buoyancy is measured in pounds) if the...

  7. 46 CFR 160.010-6 - Capacity of buoyant apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...following methods: (1) Final buoyancy of the buoyant apparatus in Newtons...divided by 145 (divided by 32 if buoyancy is measured in pounds). The divisor must be changed to 180 (40 if buoyancy is measured in pounds) if the...

  8. APPLICATION OF BUOYANT MASS TRANSFER MEDIA TO HAZARDOUS MATERIAL SPILLS

    EPA Science Inventory

    A prototype system was designed and developed to slurry buoyant activated carbon into a static body of water. The process was developed to remove spilled soluable hazardous compounds from a watercourse. In a simulated spill, up to 98% removal of Diazinon, an organophosphorus pest...

  9. Hands-On Experiences with Buoyant-Less Water

    ERIC Educational Resources Information Center

    Slisko, Josip; Planinsic, Gorazd

    2010-01-01

    The phenomenon of weightlessness is known to students thanks to videos of amazing things astronauts do in spaceships orbiting the Earth. In this article we propose two hands-on activities which give students opportunities to infer by themselves the absence of buoyant force in a gravity accelerated system. The system is a free-falling or vertically…

  10. Horizontal penetration of inclined thermal buoyant water jets

    SciTech Connect

    Pantokratoras, A. [Democritus Univ. of Thrace, Xanthi (Greece). School of Engineering] [Democritus Univ. of Thrace, Xanthi (Greece). School of Engineering

    1998-05-01

    Submerged buoyant jets occur in the discharge from thermal power plants and in the operation of pumped storage hydroelectric plants. Accurate prediction of the jet trajectory and temperature dilution are necessary if discharge structures are to be designed to meet the appropriate standards. A modified version of the integral Fan-Brooks model has been used to calculate the horizontal penetration of inclined thermal buoyant water jets. The classical densimetric Froude number F{sub 0} is substituted by a Froude number F{sub a} based on the thermal expansion coefficient of water. Using the above model, a new equation is derived which can predict the horizontal penetration of the thermal jet at a given Froude number F{sub a} and discharge angle.

  11. Experimental Study of a Buoyant Particle Dispersion in Pipe Flow

    Microsoft Academic Search

    Y. Le Guer; P. Reghem; I. Petit; B. Stutz

    2003-01-01

    n experimental investigation of a solid-liquid dispersion pipe flow was conducted using a pulsed ultrasonic Doppler velocimeter. The solid phase was composed of buoyant particles dispersed in water. This particular two-phase flow was used to mimic the behaviour of ice-water flow. Four diagnostics were used to study the complex nature of the two-phase flow mixtures: mean velocity profiles, space-time diagrams,

  12. A Neutrally Buoyant Elliptical Cylinder in Simple Shear

    Microsoft Academic Search

    Claudia Zettner; Minami Yoda

    1999-01-01

    An elliptical cylinder in simple shear (i.e., 2D, zero-mean, linearly-varying) flow is a two-dimensional Lagrangian model of a fiber in a dilute sheared suspension. Simple shear flow around a neutrally buoyant cylinder is characterized by the shear-based Reynolds number ReG ? a^2G\\/nu (G is the shear rate, a is the semi-major dimension of the cylinder, and nu is the kinematic

  13. Quantitative computational infrared imaging of buoyant diffusion flames

    NASA Astrophysics Data System (ADS)

    Newale, Ashish S.

    Studies of infrared radiation from turbulent buoyant diffusion flames impinging on structural elements have applications to the development of fire models. A numerical and experimental study of radiation from buoyant diffusion flames with and without impingement on a flat plate is reported. Quantitative images of the radiation intensity from the flames are acquired using a high speed infrared camera. Large eddy simulations are performed using fire dynamics simulator (FDS version 6). The species concentrations and temperature from the simulations are used in conjunction with a narrow-band radiation model (RADCAL) to solve the radiative transfer equation. The computed infrared radiation intensities rendered in the form of images and compared with the measurements. The measured and computed radiation intensities reveal necking and bulging with a characteristic frequency of 7.1 Hz which is in agreement with previous empirical correlations. The results demonstrate the effects of stagnation point boundary layer on the upstream buoyant shear layer. The coupling between these two shear layers presents a model problem for sub-grid scale modeling necessary for future large eddy simulations.

  14. 46 CFR 131.580 - Servicing of inflatable liferafts, inflatable lifejackets, inflatable buoyant apparatus, and...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...580 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS Tests, Drills, and Inspections § 131.580 Servicing of inflatable liferafts, inflatable lifejackets, inflatable buoyant...

  15. 46 CFR 160.010-4 - General requirements for buoyant apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...color of the buoyant apparatus must be primarily vivid reddish orange as defined by sections 13 and 14 of the “Color Names Dictionary.” (o) When fibrous-glass-reinforced plastic is used in the construction of a buoyant apparatus, each cut...

  16. 46 CFR 160.010-4 - General requirements for buoyant apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...color of the buoyant apparatus must be primarily vivid reddish orange as defined by sections 13 and 14 of the “Color Names Dictionary.” (o) When fibrous-glass-reinforced plastic is used in the construction of a buoyant apparatus, each cut...

  17. What is a flux tube? On the magnetic field topology of buoyant flux structures

    E-print Network

    What is a flux tube? On the magnetic field topology of buoyant flux structures Fausto Cattaneo study the topology of field lines threading buoyant magnetic flux struc- tures. The magnetic structures of the evolution, and therefore the degree of symmetry, the resulting magnetic structures can have field lines

  18. Incipient buoyant thermal convection in a vertical cylindrical annulus

    SciTech Connect

    Littlefield, D.L. (US Army Ballistic Research Lab., Aberdeen Proving Ground, MD (USA)); Desai, P.V. (Georgia Inst. of Tech., Atlanta (USA))

    1990-11-01

    The incipient buoyant thermal convection in a vertical cylindrical annulus when heated from below is examined. The ends are assumed to be free, and the sidewalls perfectly conducting. The temperature needed to initiate fluid motion is expressed nondimensionally in terms of the Rayleigh number. The analytical conflict that arises for annuli of infinite aspects ratios due to insufficient independent boundary conditions is resolved. Calculations for the critical Rayleigh numbers are presented for a variety of geometries, and the corresponding velocity and temperature perturbations are also shown. The number of cells increases as the aspect and radius ratio decrease with a strong bias towards the development of azimuthally varying cells. These changes in cellular behavior are expected based on physical justifications and comparisons with previous studies.

  19. The investigation of internal waves excitation by turbulent buoyant jets

    NASA Astrophysics Data System (ADS)

    Ezhova, Ekaterina; Kandaurov, Alexander; Kazakov, Vasily; Sergeev, Daniil; Troitskaya, Yuliya

    2010-05-01

    Sewage disposal by coastal cities to the ocean is an example of man's impact on offshore zone. It produces sensible stress on coastal water areas, that's why investigation of hydrodynamic processes near submerged wastewater outfalls is important. We explored these processes basing on laboratory scale modeling. The experiments were carried out in Large Thermally Stratified Tank (overall sizes 20m*4m*2m) of IAP RAS. It was shown that internal waves were generated intensively in the Tank. A hypothesis was put forward that these waves were generated by buoyant jet oscillations in the thermocline region. In order to investigate the process of generation the additional series of experiments was set up in the LTST where we used a CCD videocamera for underwater survey. A string of 13 thermistors was placed vertically in 50 cm from the source to record the temperature oscillations. The data from the camera were processed out and the spectra of jet oscillations were compared to the spectra of the internal waves. Good agreement was obtained confirming that the waves were generated by buoyant jet. The mode structure of the jet was investigated. A theoretical model was developed explaining the origin of the peaks on the internal waves spectra. Basing on the jet velocity profiles obtained by PIV method the frequencies of unstable modes were estimated. The possibilities of the self-sustained waves generation were investigated. It was shown that different regimes with two modes were possible, where one prevailed on another or they existed together depending on the parameters of experiment.

  20. The Centaurus A Northern Middle Lobe as a Buoyant Bubble

    E-print Network

    Curtis J. Saxton; Ralph S. Sutherland; Geoffrey V. Bicknell

    2001-07-30

    We model the northern middle radio lobe of Centaurus A (NGC 5128) as a buoyant bubble of plasma deposited by an intermittently active jet. The extent of the rise of the bubble and its morphology imply that the ratio of its density to that of the surrounding ISM is less than 10^{-2}, consistent with our knowledge of extragalactic jets and minimal entrainment into the precursor radio lobe. Using the morphology of the lobe to date the beginning of its rise through the atmosphere of Centaurus A, we conclude that the bubble has been rising for approximately 140Myr. This time scale is consistent with that proposed by Quillen et al. (1993) for the settling of post-merger gas into the presently observed large scale disk in NGC 5128, suggesting a strong connection between the delayed re-establishment of radio emission and the merger of NGC 5128 with a small gas-rich galaxy. This suggests a connection, for radio galaxies in general, between mergers and the delayed onset of radio emission. In our model, the elongated X-ray emission region discovered by Feigelson et al. (1981), part of which coincides with the northern middle lobe, is thermal gas that originates from the ISM below the bubble and that has been uplifted and compressed. The "large-scale jet" appearing in the radio images of Morganti et al. (1999) may be the result of the same pressure gradients that cause the uplift of the thermal gas, acting on much lighter plasma, or may represent a jet that did not turn off completely when the northern middle lobe started to buoyantly rise. We propose that the adjacent emission line knots (the "outer filaments") and star-forming regions result from the disturbance, in particular the thermal trunk, caused by the bubble moving through the extended atmosphere of NGC 5128.

  1. Shapes of Buoyant and Nonbuoyant Methane Laminar Jet Diffusion Flames

    NASA Technical Reports Server (NTRS)

    Sunderland, Peter B.; Yuan, Zeng-Guang; Urban, David L.

    1997-01-01

    Laminar gas jet diffusion flames represent a fundamental combustion configuration. Their study has contributed to numerous advances in combustion, including the development of analytical and computational combustion tools. Laminar jet flames are pertinent also to turbulent flames by use of the laminar flamelet concept. Investigations into the shapes of noncoflowing microgravity laminar jet diffusion flames have primarily been pursued in the NASA Lewis 2.2-second drop tower, by Cochran and coworkers and by Bahadori and coworkers. These studies were generally conducted at atmospheric pressure; they involved soot-containing flames and reported luminosity lengths and widths instead of the flame-sheet dimensions which are of Greater value to theory evaluation and development. The seminal model of laminar diffusion flames is that of Burke and Schumann, who solved the conservation of momentum equation for a jet flame in a coflowing ambient by assuming the velocity of fuel, oxidizer and products to be constant throughout. Roper and coworkers improved upon this model by allowing for axial variations of velocity and found flame shape to be independent of coflow velocity. Roper's suggestion that flame height should be independent of gravity level is not supported by past or present observations. Other models have been presented by Klajn and Oppenheim, Markstein and De Ris, Villermaux and Durox, and Li et al. The common result of all these models (except in the buoyant regime) is that flame height is proportional to fuel mass flowrate, with flame width proving much more difficult to predict. Most existing flame models have been compared with shapes of flames containing soot, which is known to obscure the weak blue emission of flame sheets. The present work involves measurements of laminar gas jet diffusion flame shapes. Flame images have been obtained for buoyant and nonbuoyant methane flames burning in quiescent air at various fuel flow-rates, burner diameters and ambient pressures. Soot concentrations were minimized by selecting conditions at low flowrates and low ambient pressures; this allows identification of actual flame sheets associated with blue emissions of CH and CO2. The present modeling effort follows that of Roper and is useful in explaining many of the trends observed.

  2. Channelization of buoyant nonwetting fluids in saturated porous media

    NASA Astrophysics Data System (ADS)

    Huber, C.; Parmigiani, Andrea; Latt, Jonas; Dufek, J.

    2013-10-01

    We study the development of capillary instabilities during the invasion of a buoyant nonwetting phase in a saturated porous media. Capillary instabilities are generally attributed to heterogeneities in the porous medium resulting in the existence of fluid pathways opposing different resistance to the flow ("passive control"). We use a simple macroscale theoretical model based on the postulate that the nonwetting fluid will be distributed in the porous medium to minimize the resistance to transport. This theoretical argument is used to show that after their formation, some capillary instabilities can grow at the expense of others. The competitive growth between capillary channels arises because of pore-scale fluid interactions that occur even in a porous medium offering identical pathways at the pore scale. The evolution of the pore volume fraction of nonwetting fluid in capillary fingers is therefore dynamically controlled by fluctuations in the nonwetting phase saturation and its effect on the relative permeability ("active control"). The theoretical model predicts (1) the growth of heterogeneities in nonwetting fluid saturation among competing capillary channels if the second derivative of the invading phase relative permeability with respect to its saturation is positive, and (2) that the amplitude of the perturbation in nonwetting fluid content between competing fingers increases with the interfacial tension. We use a pore-scale multiphase flow numerical model to test the validity of the postulate for optimal transport of nonwetting fluids and the two ensuing predictions. We observe that the numerical calculations are in excellent agreement with the theoretical predictions.

  3. The vertical distribution of buoyant plastics at sea

    NASA Astrophysics Data System (ADS)

    Reisser, J.; Slat, B.; Noble, K.; du Plessis, K.; Epp, M.; Proietti, M.; de Sonneville, J.; Becker, T.; Pattiaratchi, C.

    2014-11-01

    Millimeter-sized plastics are numerically abundant and widespread across the world's ocean surface. These buoyant macroscopic particles can be mixed within the upper water column due to turbulent transport. Models indicate that the largest decrease in their concentration occurs within the first few meters of water, where subsurface observations are very scarce. By using a new type of multi-level trawl at 12 sites within the North Atlantic accumulation zone, we measured concentrations and physical properties of plastics from the air-seawater interface to a depth of 5 m, at 0.5 m intervals. Our results show that plastic concentrations drop exponentially with water depth, but decay rates decrease with increasing Beaufort scale. Furthermore, smaller pieces presented lower rise velocities and were more susceptible to vertical transport. This resulted in higher depth decays of plastic mass concentration (mg m-3) than numerical concentration (pieces m-3). Further multi-level sampling of plastics will improve our ability to predict at-sea plastic load, size distribution, drifting pattern, and impact on marine species and habitats.

  4. EVALUATION OF A CONVECTIVE SCALING PARAMETERIZATION FOR ESTIMATING THE DIFFUSION OF A BUOYANT PLUME

    EPA Science Inventory

    During limited-mixed convective conditions, high concentrations of air pollutants have been observed at ground-level from buoyant plumes. Routinely-applied Gaussian plume dispersion models have difficulty simulating diffusion for these conditions. However, advances in convective ...

  5. 46 CFR 117.137 - Stowage of life floats and buoyant apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...MORE THAN 49 PASSENGERS LIFESAVING EQUIPMENT AND ARRANGEMENTS Survival Craft Arrangements and Equipment § 117.137 Stowage of life floats...buoyant apparatus is considered a single survival craft for the purposes of §...

  6. 46 CFR 180.137 - Stowage of life floats and buoyant apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...UNDER 100 GROSS TONS) LIFESAVING EQUIPMENT AND ARRANGEMENTS Survival Craft Arrangements and Equipment § 180.137 Stowage of life floats...buoyant apparatus is considered a single survival craft for the purposes of §...

  7. A change in a single gene of Salmonella typhimurium can dramatically change its buoyant density.

    PubMed Central

    Baldwin, W W; Kirkish, M A; Koch, A L

    1994-01-01

    The growth rates and buoyant densities of a Salmonella typhimurium mutant, TL126 (proB74A+), with enhanced osmotolerance caused by proline overproduction were measured and compared with the growth rates and buoyant densities of an isogenic (wild-type) strain, TL128 (proB+ A+), with normal control of proline production. Growth rates were determined in a rich medium (Luria broth) with added NaCl to produce various osmotic strengths ranging from 300 to 2,000 mosM. At low concentrations of NaCl, there was little variation in doubling times between the two strains. However, as the osmotic strength of the medium approached and exceeded 1,300 mosM, the doubling times of TL126 (osmotolerant) were 1.5 to 2 times faster than those of TL128 (wild type), confirming the osmotolerance of TL126. Buoyant densities were determined by equilibrium sedimentation in a Percoll gradient of osmotic strength equal to that of the growth medium. The osmolarity of the Percoll gradient was adjusted by the addition of NaCl. At low osmolarities (300 to 500 mosM), the buoyant density of TL126 (osmotolerant) was slightly but consistently lower than that of TL128 (wild type). As the osmotic strength was increased, the buoyant density of TL126 (osmotolerant) increased in proportion to the osmotic strength. In contrast, the buoyant density of strain TL128 (wild type) did not increase as much. At high osmolarities (1,600 to 2,000 mosM), the buoyant density of TL126 (osmotolerant) was consistently higher than that of TL128 (wild type). These results suggest that the intracellular accumulation of proline by TL126, the osmotolerant strain, increases both the growth rates and buoyant densities at osmolarities of 1,300 mosM and above. PMID:8051013

  8. Surface buoyant plumes from melting icebergs in the Labrador Sea

    NASA Astrophysics Data System (ADS)

    Yankovsky, Alexander E.; Yashayaev, Igor

    2014-09-01

    Canada's Department of Fisheries and Oceans (DFO) conducts annual surveys in the Labrador Sea along the repeat hydrography line AR7W. The occupation of the AR7W line in May 2013 was followed by the experiment aimed at resolving the imprint of melting drifting icebergs on the upper layer thermohaline characteristics in the Labrador Sea. We present high-resolution observations around two icebergs conducted with the towed undulating platform Moving Vessel Profiler (MVP). The first iceberg drifted in relatively warm water of Atlantic origin (~2.5-3.1 °C) off Greenland, while the second iceberg was on the Labrador shelf in cold water below 0 °C. Both icebergs had a lengthscale of O(100 m). In both cases surface buoyant plumes fed by melt water and attached to the iceberg were observed. The plumes were evident in the anomalous thermohaline characteristics of the seawater. Their density anomalies were sufficiently strong to produce visible frontal structures, which imply a development of the intrinsic dynamics associated with a plume. The first plume formed over a time interval of ~10 h, while the second plume formed over several days and extended for more than 1 km (tenfold the iceberg's size). Strong vertical displacements of the pycnocline were observed near the second iceberg. They are interpreted as the internal wave wake. This interpretation is based on the temporal scale of these oscillations (local buoyancy frequency), as well as on the spatial orientation of these waves with respect to the iceberg drift relative to the pycnocline. The observed internal waves partially overlapped with the plume and affected its structure. The saline seawater splashing by swell contributed to the surface melting of the icebergs. Scaling analysis of the second plume suggests that it could be in the “rotational” dynamic regime with recirculating anticyclonic flow.

  9. Buoyant subduction on Venus: Implications for subduction around coronae

    NASA Technical Reports Server (NTRS)

    Burt, J. D.; Head, J. W.

    1993-01-01

    Potentially low lithospheric densities, caused by high Venus surface and perhaps mantle temperatures, could inhibit the development of negative buoyancy-driven subduction and a global system of plate tectonics/crustal recycling on that planet. No evidence for a global plate tectonic system was found so far, however, specific features strongly resembling terrestrial subduction zones in planform and topographic cross-section were described, including trenches around large coronae and chasmata in eastern Aphrodite Terra. The cause for the absence, or an altered expression, of plate tectonics on Venus remains to be found. Slab buoyancy may play a role in this difference, with higher lithospheric temperatures and a tendency toward positive buoyancy acting to oppose the descent of slabs and favoring under thrusting instead. The effect of slab buoyancy on subduction was explored and the conditions which would lead to under thrusting versus those allowing the formation of trenches and self-perpetuating subduction were defined. Applying a finite element code to assess the effects of buoyant forces on slabs subducting into a viscous mantle, it was found that mantle flow induced by horizontal motion of the convergent lithosphere greatly influences subduction angle, while buoyancy forces produce a lesser effect. Induced mantle flow tends to decrease subduction angle to near an under thrusting position when the subducting lithosphere converges on a stationary overriding lithosphere. When the overriding lithosphere is in motion, as in the case of an expanding corona, subduction angles are expected to increase. An initial stage involved estimating the changes in slab buoyancy due to slab healing and pressurization over the course of subduction. Modeling a slab, descending at a fixed angle and heated by conduction, radioactivity, and the heat released in phase changes, slab material density changes due to changing temperature, phase, and pressure were derived.

  10. Wave induced transport and mixing of buoyant particles

    NASA Astrophysics Data System (ADS)

    Drivdal, Magnus; Broström, Göran; Christensen, Kai H.

    2014-05-01

    The modeling of wave-current and wave-turbulence interactions have received much attention during recent years. Both the breaking of surface waves and the inclusion of the Stokes shear production have been shown to increase the upper ocean turbulence. Furthermore the Coriolis force acting on the Stokes drift redistributes the momentum in the upper ocean, leading to a deflection of the currents. An important application affected by these processes that still needs to be studied is the mixing and drift of particles. Using an ocean column model, modified to take surface wave effects into account, we investigate how the increased mixing by wave breaking and Stokes shear production as well as the stronger veering by the Coriolis-Stokes force effects the drift of suspended particles. Here the suspended particles are buoyant tracers that can represent oil droplets or plankton, for example fish eggs and larvae. The energy and momentum fluxes as well as the Stokes drift depend on the directional wave spectrum that can be obtained from a wave model or from observations. Comparing with classical Ekman theory some physical effects on the system are studied, and as a realistic test case we use the model to study the oil drift after an offshore oil spill that took place outside the western coast of Norway in 2007. During this accident the average net drift of oil was observed to be approximately 0.1% of the wind speed at an angle of about 90-120 degrees to the right, far slower and more deflected away from the wind direction than predicted by both numerical and empirical models. With wind and wave forcing from ECMWF reanalysis data, it is shown that the wave effects are important for the resultant drift in this case, and has the potential to improve drift forecasting.

  11. Surface Buoyant Plumes from Melting Icebergs in the Labrador Sea

    NASA Astrophysics Data System (ADS)

    Yankovsky, Alexander; Yashayaev, Igor

    2014-05-01

    Canada's Department of Fisheries and Oceans (DFO) conducts annual surveys in the Labrador Sea along the repeat hydrography line AR7W. Since 2012, these shipboard surveys have been supplemented by underway CTD and optical measurements in the upper 200 m layer conducted with the towed undulating platform Moving Vessel Profiler (MVP). The MVP hydrographic data reveal rich variability of the upper layer salinity field on different spatial scales. The occupation of the AR7W line in May 2013 was followed by the experiment aimed at resolving the imprint of melting drifting icebergs on the upper layer thermohaline characteristics in the Labrador Sea. Here we present observations around two icebergs: the first iceberg drifted in relatively warm water of Atlantic origin (~2.5-3.1°C) off Greenland, while the second iceberg was on the Labrador shelf in cold water below 0°C. Both icebergs had a lengthscale of O(100 m). In both cases surface buoyant plumes fed by melt water and attached to the iceberg were observed. The plumes were evident in the anomalous thermohaline characteristics of the seawater. Their density anomalies were sufficiently strong to produce visible frontal structures, which imply a development of the intrinsic dynamics associated with a plume. The first plume formed over a time interval of ~10 hr, while the second plume formed over several days and extended for more than 1 km (tenfold the iceberg's size). Strong vertical displacements of the pycnocline were observed near the second iceberg. They are interpreted as the internal wave wake. This interpretation is based on the temporal scale of these oscillations (local buoyancy frequency), as well as on the spatial orientation of these waves with respect to the iceberg drift relative to the pycnocline. The observed internal waves partially overlapped with the plume and affected its structure. The saline seawater splashing by swell contributed to the surface melting of the icebergs. Scaling analysis of the observed plume suggests that it could be in the "rotational" dynamic regime with recirculating anticyclonic flow. In this case the melt water is trapped in the plume and affects the iceberg's thermodynamics and the rate of melt. These effects are likely to be more pronounced near bigger icebergs or ice islands, and will be a focus of our future observational campaign.

  12. 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)

    Rudnicki, M. D.; Elderfield, H.

    1993-07-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    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.

  14. Experiments versus modeling of buoyant drying of porous media

    NASA Astrophysics Data System (ADS)

    Salin, D.; Yiotis, A.; Tajer, E.; Yortsos, Y. C.

    2012-12-01

    Experiments versus modeling of buoyant drying of porous media D. Salin and A.G. Yiotis, Laboratoire FAST, Univ Pierre & Marie Curie, Univ. Paris-Sud, CNRS, Orsay 91405, France and E.S. Tajer and Y.C. Yortsos, Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1450 A series of isothermal drying experiments in packed glass beads saturated with volatile hydrocarbons (hexane or pentane) are conducted. The transparent glass cells containing the packing allow for the visual monitoring of the phase distribution patterns below the surface, including the formation of liquid films, as the gaseous phase invades the pore space, and for the control of the thickness of the diffusive mass boundary layer over the packing. We demonstrate the existence of an early Constant Rate Period, CRP, that lasts as long as the films saturate the surface of the packing, and of a subsequent Falling Rate Period, FRP, that begins practically after the detachment of the film tips from the external surface. During the CRP, the process is controlled by diffusion within the stagnant gaseous phase in the upper part of the cells, yielding a Stefan tube problem solution. During the FRP, the process is controlled by diffusion within the packing, with a drying rate inversely proportional to the observed position of the film tips in the cell. The critical residual liquid saturation that marks the transition between these two regimes is found to be a function of the average bead size in our packs and the incline of the cells with respect to the flat vertical, with larger beads and angles closer to the vertical position leading to earlier film detachment times and higher critical saturations. We developed a model for the drying of porous media in the presence of gravity. It incorporated effects of corner film flow, internal and external mass transfer and the effect of gravity. Analytical results were derived when gravity opposes drying and hence leads to a stable percolation drying front. We are thus able to obtain results for the drying rates, the critical saturation and the extent of the film region with respect to the various dimensionless numbers that describe the process; the Bond (Bo)number, a film-based Capillary (Ca) number and the dimensionless extent of the mass boundary layer (Sh). The experimental results agree very well with the theory, provided that the latter is generalized to account for the effects of corner roundness in the film region which were neglected in our analytical approach. The agreement is achieved for a specific value of the roundness of the films, which is found to be constant and equal to 0.2 for various conditions, and verify the theoretical dependence on Ca, Bo and Sh numbers.

  15. Buoyant convection resulting from dissolution and permeability growth in vertical limestone fractures

    NASA Astrophysics Data System (ADS)

    Chaudhuri, A.; Rajaram, H.; Viswanathan, H.; Zyvoloski, G.; Stauffer, P.

    2009-02-01

    Upward flow through vertical fractures in limestone formations under a geothermal gradient favors dissolution and permeability growth. We investigate the transition from conductive and forced convective regimes to instability and buoyant convection as a result of permeability growth. The onset time for instability and roll height at onset depend on the initial aperture and driving pressure. A modified Rayleigh number criterion is proposed, which provides a unified interpretation of the instability across a wide range of initial aperture and driving pressure. Interaction between buoyant convection and aperture alteration leads to narrow upward flow paths supporting dissolution and precipitation in surrounding downward flow regions.

  16. Structure and Soot Properties of Non-Buoyant Laminar Round-Jet Diffusion Flames

    NASA Technical Reports Server (NTRS)

    Mortazavi, Saeed; Sunderland, Peter B.; Jurng, Jongsoo; Faeth, Gerard M.

    1993-01-01

    The structure and soot properties of nonbuoyant laminar diffusion flames are being studied experimentally and theoretically in order to better understand the soot and thermal radiation emissions from luminous flames. The measurements involve weakly-buoyant flames at low pressure in normal gravity (ng) and nonbuoyant flames at normal pressures in microgravity (micro g). The objectives of the present investigation are to study the differences of soot properties between nonbuoyant and buoyant diffusion flames, and to evaluate predictions based on the laminar flamelet approach.

  17. Preliminary study of ground handling characteristics of Buoyant Quad Rotor (BQR) vehicles

    NASA Technical Reports Server (NTRS)

    Browning, R. G. E.

    1980-01-01

    A preliminary investigation of mooring concepts appropriate for heavy lift buoyant quad rotor (BQR) vehicles was performed. A review of the evolution of ground handling systems and procedures for all airship types is presented to ensure that appropriate consideration is given to past experiences. Two buoyant quad rotor designs are identified and described. An analysis of wind loads on a moored airship and the effects of these loads on vehicle design is provided. Four mooring concepts are assessed with respect to the airship design, wind loads and mooring site considerations. Basing requirements and applicability of expeditionary mooring at various operational scenarios are addressed.

  18. Note: Buoyant-force assisted liquid membrane electrochemical etching for nano-tip preparation

    NASA Astrophysics Data System (ADS)

    Zeng, Yongbin; Wang, Yufeng; Wu, Xiujuan; Xu, Kun; Qu, Ningsong

    2014-12-01

    A liquid membrane electrochemical etching process for preparing nano-tips is proposed by the introduction of buoyant force to the lower tip, in which the lower portion of the anodic wire is immersed into a floating layer. A mathematical model of this method is derived. Both calculation and experimental results demonstrate that the introduction of buoyant force can significantly decrease the tip radius. The lubricating oil and deionized water floating layers were tested for the processing of nano-tips. Further, high-aspect-ratio nano-electrodes were prepared by applying a relative vertical movement to the anodic wire.

  19. (Revised May 22, 2012) (1) To experimentally determine the relationship between the buoyant forces on an object that

    E-print Network

    Collins, Gary S.

    ON AN OBJECT DENSER THAN WATER Refer to the Force Sensor section of the Computer Tools Supplement at the back the buoyant forces on an object that displaces known weights of water. (2) To compare the buoyant behavior of an object more dense than water with an object less dense than water. (3) To calculate the densities

  20. (Revised May 22, 2012) (1) To experimentally determine the relationship between the buoyant forces on objects that

    E-print Network

    Collins, Gary S.

    FORCE ON AN OBJECT DENSER THAN WATER Refer to the Force Sensor section of the Computer Tools Supplement the buoyant forces on objects that displace known weights of water. (2) To compare the buoyant behavior of an object more dense than water with an object less dense than water. (3) To calculate the densities

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

    SciTech Connect

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

    2012-02-03

    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.

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

    ERIC Educational Resources Information Center

    Radovanovic, Jelena; Slisko, Josip

    2013-01-01

    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…

  3. 46 CFR 160.010-4 - General requirements for buoyant apparatus.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...festooned in bights no longer than 1 m (3 ft.), with a seine float in each bight, unless the line is of an inherently buoyant...160.010-1 of this subpart). (o) When fibrous-glass-reinforced plastic is used in the construction of a...

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

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...festooned in bights no longer than 1 m (3 ft.), with a seine float in each bight, unless the line is of an inherently buoyant...160.010-1 of this subpart). (o) When fibrous-glass-reinforced plastic is used in the construction of a...

  5. 46 CFR 160.010-4 - General requirements for buoyant apparatus.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...festooned in bights no longer than 1 m (3 ft.), with a seine float in each bight, unless the line is of an inherently buoyant...160.010-1 of this subpart). (o) When fibrous-glass-reinforced plastic is used in the construction of a...

  6. Modelling the fate and transport of negatively buoyant stormriver water in small multi-basin lakes

    E-print Network

    California at Santa Barbara, University of

    Modelling the fate and transport of negatively buoyant storm­river water in small multi-basin lakes-term productivity of lacustrine ecosystems (Robarts, 1987; Elber and Schanz, 1990; Barbiero et al., 1999). The response of aquatic ecosystems to such events largely depends on the fate of storm river water which may

  7. Radiative Heating and the Buoyant Rise of Magnetic Flux Tubes in the Solar Interior

    E-print Network

    California at Berkeley, University of

    Radiative Heating and the Buoyant Rise of Magnetic Flux Tubes in the Solar Interior Y. Fan National tube. In the overshoot region, the radiative heating is found to cause a quasi-static rising the e ect of radiative heating on the evolution of thin magnetic ux tubes in the solar interior

  8. Buoyant gravity currents along a sloping bottom in a rotating fluid

    Microsoft Academic Search

    STEVEN J. LENTZ; KARL R. HELFRICH

    2002-01-01

    The dynamics of buoyant gravity currents in a rotating reference frame is a classical problem relevant to geophysical applications such as river water entering the ocean. However, existing scaling theories are limited to currents propagating along a vertical wall, a situation almost never realized in the ocean. A scaling theory is proposed for the structure (width and depth), nose speed

  9. Hydrodynamic diffusion and mass transfer across a sheared suspension of neutrally buoyant spheres

    Microsoft Academic Search

    Luying Wang; Donald L. Koch; Xiaolong Yin; Claude Cohen

    2009-01-01

    We present experimental, theoretical, and numerical simulation studies of the transport of fluid-phase tracer molecules from one wall to the opposite wall bounding a sheared suspension of neutrally buoyant solid particles. The experiments use a standard electrochemical method in which the mass transfer rate is determined from the current resulting from a dilute concentration of ions undergoing redox reactions at

  10. BUOYANT PLUME DISPERSAL IN THE CONVECTIVE BOUNDARY LAYER: ANALYSIS OF EXPERIMENTAL DATA AND LAGRANGIAN MODELING

    EPA Science Inventory

    The aim of this research program is to improve our knowledge and predictive capability of buoyant plume dispersion in the convective boundary layer (CBL) with emphasis on the mean (C) and root-mean-square (?c) concentration fields. The CBL turbulence leads to large random fluc...

  11. 3D Numerical Simulation of Turbulent Buoyant Flow and Heat Transport in a Curved Open Channel

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A three-dimensional buoyancy-extended version of kappa-epsilon turbulence model was developed for simulating the turbulent flow and heat transport in a curved open channel. The density- induced buoyant force was included in the model, and the influence of temperature stratification on flow field was...

  12. Characteristics of flammable, buoyant hydrogen plumes rising from open vertical containers

    Microsoft Academic Search

    S. Fardisi; Ghazi A. Karim

    2009-01-01

    The dynamics of the dispersion of a fixed mass of the highly buoyant hydrogen when exposed to overlaying atmosphere with a negligible pressure difference from open vertical cylindrical enclosures are examined. Features of the rapid formation and dispersion of flammable mixtures both inside and immediate outside of the enclosure and their corresponding propagation rates were examined using a 3-D CFD

  13. Growth and buoyant density of Escherichia coli at very low osmolarities.

    PubMed Central

    Baldwin, W W; Myer, R; Kung, T; Anderson, E; Koch, A L

    1995-01-01

    The growth and buoyant densities of two closely related strains of Escherichia coli in M9-glucose medium that was diluted to produce osmolarities that varied from as low as 5 to 500 mosM were monitored. At 15 mosM, the lowest osmolarity at which buoyant density could be measured reproducibly in Percoll gradients, both ML3 and ML308 had a buoyant density of about 1.079 g/ml. As the osmolarity of the medium was increased, the buoyant density also increased linearly up to about 125 mosM, at which the buoyant density was 1.089 g/ml. From 150 up to 500 mosM, the buoyant density again increased linearly but with a different slope from that seen at the lower osmolarities. The buoyant density at 150 mosM was about 1.091 g/ml, and at 500 mosM it was 1.101 g/ml. Both strains of E. coli could be grown in M9 medium diluted 1:1 with water, with an osmolarity of 120 mosM, but neither strain grew in 1:2-diluted M9 if the cells were pregrown in undiluted M9. (Note: undiluted M9 as prepared here has an osmolarity of about 250 mosM.) However, if the cells were pregrown in 30% M9, about 75 mosM, they would then grow in M9 at 45 mosM and above but not below 40 mosM. To determine which constituent of M9 medium was being diluted to such a low level that it inhibited growth, diluted M9 was prepared with each constituent added back singly. From this study, it was determined that both Ca2+ and Mg2+ could stimulate growth below 40 mosM. With Ca2+ - and Mg2+ -supplemented diluted M9 and cells pregrown in 75 mosM M9, it was possible to grow ML308 in 15 mosM M9. Strain ML3 would only haltingly grow at 15 mosM. Four attempts were made to grow both ML3 and ML308 at 5 mosM. In three of the experiments, ML308 grew, while strain ML3 grew in one experiment. While our experiments were designed to effect variations in medium osmolarity by using NaCl as an osmotic agent, osmolarity and salinity were changed concurrently. Therefore, from this study, we believe that E. coli might be defined as an euryhalinic and/or euryosmotic bacterium because of its ability to grow in a wide range of salinities and osmolarities. PMID:7798137

  14. A buoyant plume adjacent to a headland-Observations of the Elwha River plume

    USGS Publications Warehouse

    Warrick, J.A.; Stevens, A.W.

    2011-01-01

    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 on the western side of its deltaic headland. Here we show that this headland induces flow separation and transient eddies in the tidally dominated currents (O(100. cm/s)), consistent with other headlands in oscillatory flow. These flow conditions are observed to strongly influence the buoyant river plume, as predicted by the "small-scale" or "narrow" dynamical classification using Garvine's (1995) system. Because of the transient eddies and the location of the river mouth on the headland, flow immediately offshore of the river mouth is directed eastward twice as frequently as it is westward. This results in a buoyant plume that is much more frequently "bent over" toward the east than the west. During bent over plume conditions, the plume was attached to the eastern shoreline while having a distinct, cuspate front along its westernmost boundary. The location of the front was found to be related to the magnitude and direction of local flow during the preceding O(1. h), and increases in alongshore flow resulted in deeper freshwater mixing, stronger baroclinic anomalies, and stronger hugging of the coast. During bent over plume conditions, we observed significant convergence of river plume water toward the frontal boundary within 1. km of the river mouth. These results show how coastal topography can strongly influence buoyant plume behavior, and they should assist with understanding of initial coastal sediment dispersal pathways from the Elwha River during a pending dam removal project. ?? 2010.

  15. Comparative Large Eddy Simulation study of a large-scale buoyant fire

    Microsoft Academic Search

    G. H. Yeoh; S. C. P. Cheung; J. Y. Tu; T. J. Barber

    A fully-coupled Large Eddy Simulation model which incorporates all essential combustion, radiation and soot chemistry considerations\\u000a have been developed to simulate the temporal vortical structure of a large-scale buoyant fire. Numerical results are validated\\u000a and compared against a full-scale fire measurements and predictions from other LES models. Quantitative comparisons against\\u000a experimental data suggested that the present model successfully captured the

  16. On the Alignment of Strain, Vorticity and Scalar Gradient in Turbulent, Buoyant, Nonpremixed Flames

    NASA Technical Reports Server (NTRS)

    Boratav, O. N.; Elghobashi, S. E.; Zhong, R.

    1999-01-01

    The alignment of vorticity and scalar gradient with the eigendirections of the rate of strain tensor is investigated in turbulent buoyant nonpremixed horizontal and vertical flames. The uniqueness of a buoyant nonpremixed flame is that it contains regions with distinct alignment characteristics. The strain-enstrophy angle Psi is used to identify these regions. Examination of the vorticity field and the vorticity production in these different regions indicates that Psi and consequently the alignment properties near the flame surface identified by the mixture fraction band F approximately equals F(sub st) differ from those in the fuel region, F > F(sub st) and the oxidizer region, F < F(sub st). The F approximately equals F(sub st) band shows strain-dominance resulting in vorticity/alpha alignment while F > F(sub st) (and F < F(sub st) for the vertical flame) band(s) show(s) vorticity/beta alignment. The implication of this result is that the scalar dissipation, epsilon(sub F), attains its maximum value always near F approximately equals F(sub st). These results are also discussed within the framework of recent dynamical results [Galanti et al., Nonlinearity 10, 1675 (1997)] suggesting that the Navier-Stokes equations evolved towards an attracting solution. It is shown that the properties of such an attracting solution are also consistent with our results of buoyant turbulent nonpremixed flames.

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

    SciTech Connect

    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

    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.

  18. Integral Model for Turbulent Buoyant Jets in Unbounded Stratified Flows Part 2: Plane Jet Dynamics Resulting from Multiport Diffuser Jets

    Microsoft Academic Search

    Gerhard H. Jirka

    2006-01-01

    An integral model for the plane buoyant jet dynamics resulting from the interaction of multiple buoyant jet effluxes spaced\\u000a along a diffuser line is considered as an extension of the round jet formulation that was proposed in Part I. The receiving\\u000a fluid is given by an unbounded ambient environment with uniform density or stable density stratification and under stagnant\\u000a or

  19. Structure of self-preserving plane buoyant turbulent free line plumes and adiabatic wall plumes

    NASA Astrophysics Data System (ADS)

    Sangras, Ravikiran

    2000-11-01

    An experimental investigation of the self-preserving properties of buoyant turbulent plumes is described. The research is motivated by the need to resolve effects of buoyancy/turbulence interactions and to provide data required to benchmark models of buoyant turbulent flows for fire environments. The flows considered included free line plumes and adiabatic wall plumes in an attempt to learn more about buoyant turbulent flows typical of the environment of unwanted fires. Measurements included laser-induced iodine fluorescence (LIF) to find mixture fraction statistics and laser-Doppler velocimetry (LDV) to find velocity statistics. Present measurements emphasized self-preserving conditions far from the source where effects of source disturbances and momentum have been lost. The plumes were simulated using helium/air sources in a still and unstratified environment and rising along a smooth plane and vertical wall. Present measurements of plane buoyant turbulent plumes extended farther from the source (up to 155 source widths) and had more accurate specifications of plume buoyancy fluxes than past measurements. Self-preserving behavior of free line plumes was observed 76--155 source widths above the source, yielding smaller normalized plume widths and different scaled mean and fluctuating mixture fractions near the plane of symmetry than previously thought. Measurements of probability density functions, temporal power spectra and temporal integral scales of mixture fluctuations are also reported. Self-preserving behavior of adiabatic wall plumes was observed 92--155 source widths above the source, yielding smaller normalized plume widths and near wall mean mixture fractions than earlier measurements. Present measurements of velocity properties yielded smaller normalized plume widths and larger near wall mean velocities than observations within the flow development region nearer to the source. Unlike observations of concentration fluctuations, which are unusually large due to effects of streamwise buoyant instabilities, velocity fluctuation intensities were comparable to values observed in nonbuoyant turbulent wall jets. The entrainment properties of the present flows approximated self-preserving behavior in spite of the continued development of the wall boundary layer. Measurements of probability density functions, temporal and spatial integral scales of mixture fraction and velocity fluctuations are also reported. Self-preserving adiabatic wall plumes mix slower than comparable free line plumes because the wall prevents mixing on one side and inhibits large-scale turbulent motion. This reduced rate of mixing for turbulent wall flows is a concern in fires because it extends the length of the flame-containing region and reduces effects of dilution on reducing temperature levels and toxic gas concentrations in overfire plumes.

  20. Numerical simulations of negatively buoyant jets in an immiscible fluid using the Particle Finite Element Method

    NASA Astrophysics Data System (ADS)

    Mier-Torrecilla, Monica; Geyer, Adelina; Phillips, Jeremy C.; Idelsohn, Sergio R.; Oñate, Eugenio

    2010-05-01

    In this work we investigate numerically the injection of a negatively buoyant jet into a homogenous immiscible ambient fluid using the Particle Finite Element Method (PFEM), a newly developed tool that combines the flexibility of particle-based methods with the accuracy of the finite element discretization. In order to test the applicability of PFEM to the study of negatively buoyant jets, we have compared the two-dimensional numerical results with experiments investigating the injection of a jet of dyed water through a nozzle in the base of a cylindrical tank containing rapeseed oil. In both simulations and experiments, the fountain inlet flow velocity and nozzle diameter were varied to cover a wide range of Reynolds Re and Froude numbers Fr, such that 0.1 < Fr < 30, reproducing both weak and strong fountains in a laminar regime (8 < Re < 1350). Numerical results, together with the experimental observations, allow us to describe three different fountain behaviors that have not been previously reported. Based on the Re and Fr values for the numerical and experimental simulations, we have built a regime map to define how these values may control the occurrence of each of the observed flow types. Whereas the Fr number itself provides a prediction of the maximum penetration height of the jet, its combination with the Re number provides a prediction of the flow behavior for a specific nozzle diameter and injection velocity. Conclusive remarks concerning the dynamics of negatively buoyant jets may be applied later on to several geological situations, e.g. the flow structure of a fully submerged subaqueous eruptive vent discharging magma or the replenishment of magma chambers in the Earth's crust.

  1. An improved genetic system for bioengineering buoyant gas vesicle nanoparticles from Haloarchaea

    PubMed Central

    2013-01-01

    Background Gas vesicles are hollow, buoyant organelles bounded by a thin and extremely stable protein membrane. They are coded by a cluster of gvp genes in the halophilic archaeon, Halobacterium sp. NRC-1. Using an expression vector containing the entire gvp gene cluster, gas vesicle nanoparticles (GVNPs) have been successfully bioengineered for antigen display by constructing gene fusions between the gvpC gene and coding sequences from bacterial and viral pathogens. Results To improve and streamline the genetic system for bioengineering of GVNPs, we first constructed a strain of Halobacterium sp. NRC-1 deleted solely for the gvpC gene. The deleted strain contained smaller, more spindle-shaped nanoparticles observable by transmission electron microscopy, confirming a shape-determining role for GvpC in gas vesicle biogenesis. Next, we constructed expression plasmids containing N-terminal coding portions or the complete gvpC gene. After introducing the expression plasmids into the Halobacterium sp. NRC-1 ?gvpC strain, GvpC protein and variants were localized to the GVNPs by Western blotting analysis and their effects on increasing the size and shape of nanoparticles established by electron microscopy. Finally, a synthetic gene coding for Gaussia princeps luciferase was fused to the gvpC gene fragments on expression plasmids, resulting in an enzymatically active GvpC-luciferase fusion protein bound to the buoyant nanoparticles from Halobacterium. Conclusion GvpC protein and its N-terminal fragments expressed from plasmid constructs complemented a Halobacterium sp. NRC-1 ?gvpC strain and bound to buoyant GVNPs. Fusion of the luciferase reporter gene from Gaussia princeps to the gvpC gene derivatives in expression plasmids produced GVNPs with enzymatically active luciferase bound. These results establish a significantly improved genetic system for displaying foreign proteins on Halobacterium gas vesicles and extend the bioengineering potential of these novel nanoparticles to catalytically active enzymes. PMID:24359319

  2. Buoyant Bubbles

    NSDL National Science Digital Library

    2012-06-26

    What keeps bubbles and other things, like airplanes, floating or flying in the air? In this activity, learners blow bubbles and wave 3x5 cards above, below and on different sides of the bubbles to keep them afloat as long as possible. The Did You Know section explains the Bernoulli principle: how waving cards above the bubbles helps keep them afloat because faster moving air exerts less pressure to push the bubbles down. The activity can be extended by having learners wave their bubbles through an obstacle course they design themselves.

  3. Buoyant Boats

    NSDL National Science Digital Library

    Engineering K-PhD Program,

    Students conduct a simple experiment to see how the water level changes in a beaker when a lump of clay sinks in the water and when the same lump of clay is shaped into a bowl that floats in the water. They notice that the floating clay displaces more water than the sinking clay does, perhaps a surprising result. Then they determine the mass of water that is displaced when the clay floats in the water. A comparison of this mass to the mass of the clay itself reveals that they are approximately the same.

  4. Iron isotope fractionation in a buoyant hydrothermal plume, 5°S Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Bennett, Sarah A.; Rouxel, Olivier; Schmidt, Katja; Garbe-Schönberg, Dieter; Statham, Peter J.; German, Christopher R.

    2009-10-01

    Fe isotopes are a potential tool for tracing the biogeochemical redox cycle of Fe in the ocean. Specifically, it is hypothesized that Fe isotopes could enable estimation of the contributions from multiple Fe sources to the dissolved Fe budget, an issue that has received much attention in recent years. The first priority however, is to understand any Fe isotope fractionation processes that may occur as Fe enters the ocean, resulting in modification of original source compositions. In this study, we have investigated the Fe inputs from a basalt-hosted, deep-sea hydrothermal system and the fractionation processes that occur as the hot, chemically reduced and acidic vent fluids mix with cold, oxygen-rich seawater. The samples collected were both end-member vent fluids taken from hydrothermal chimneys, and rising buoyant plume samples collected directly above the same vents at 5°S, Mid-Atlantic Ridge. Our analyzes of these samples reveal that, for the particulate Fe species within the buoyant plume, 25% of the Fe is precipitated as Fe-sulfides. The isotope fractionation caused by the formation of these Fe-sulfides is ?Fe(II)-FeS = +0.60 ± 0.12‰. The source isotope composition for the buoyant plume samples collected above the Red Lion vents is calculated to be -0.29 ± 0.05‰. This is identical to the value measured in end-member vent fluids collected from the underlying "Tannenbaum" chimney. The resulting isotope compositions of the Fe-sulfide and Fe-oxyhydroxide species in this buoyant plume are -0.89 ± 0.11‰ and -0.19 ± 0.09‰, respectively. From mass balance calculations, we have been able to calculate the isotope composition of the dissolved Fe fraction, and hypothesize that the isotope composition of any stabilised dissolved Fe species exported to the surrounding ocean may be heavier than the original vent fluid. Such species would be expected to travel some distance from areas of hydrothermal venting and, hence, contribute to not only the dissolved Fe budget of the deep-ocean but also it's dissolved Fe isotope signature.

  5. Large Eddy Simulation of a Forced Round Turbulent Buoyant Plume in Neutral Surroundings

    NASA Technical Reports Server (NTRS)

    Basu, A. J.; Mansour, N. N.; Koga, Dennis (Technical Monitor)

    1999-01-01

    Buoyant flows play an important role in various technological and environmental issues. For example, dispersal of pollutants, smoke, or volcano exhaust in the atmosphere, vertical motion of air, formation of clouds and other weather systems, and flows in cooling towers and fires are all determined primarily by buoyancy effects. The buoyancy force in such flows can originate from either a heat source or due to different densities between a fluid and its surroundings. Whatever the cause, the flow can be understood by studying the effects of the tight coupling between the thermal and the velocity fields since density differences can be characterized as temperature differences.

  6. Simultaneous Measurement of Temperature and Velocity in Turbulent Buoyant Plume by Combined LIF and PIV Technique

    SciTech Connect

    Yoshie Watanabe; Yuji Hashizume; Nobuyuki Fujisawa [Niigata University, Niigata City 950-2181 (Japan)

    2006-07-01

    An experimental technique for simultaneous measurement of temperature and velocity in a thermal flow is described. This technique is based on the two-color laser-induced fluorescence technique combined with the particle image velocimetry. Illumination is provided from Nd: YAG laser and the fluorescent dyes are chosen as Rhodamine B and Fluorescent Sodium, which combination allows the accurate velocity measurement in a wide range of flow velocity and high temperature sensitivity in temperature measurement. The measurement of temperature and velocity in turbulent buoyant plume is carried out by this method, and the structure of the plume is studied in connection with the entrainment of surrounding fluid at the interface. (authors)

  7. Characterization of Buoyant Fluorescent Particles for Field Observations of Water Flows

    PubMed Central

    Tauro, Flavia; Aureli, Matteo; Porfiri, Maurizio; Grimaldi, Salvatore

    2010-01-01

    In this paper, the feasibility of off-the-shelf buoyant fluorescent microspheres as particle tracers in turbid water flows is investigated. Microspheres’ fluorescence intensity is experimentally measured and detected in placid aqueous suspensions of increasing concentrations of clay to simulate typical conditions occurring in natural drainage networks. Experiments are conducted in a broad range of clay concentrations and particle immersion depths by using photoconductive cells and image-based sensing technologies. Results obtained with both methodologies exhibit comparable trends and show that the considered particles are fairly detectable in critically turbid water flows. Further information on performance and integration of the studied microspheres in low-cost measurement instrumentation for field observations is obtained through experiments conducted in a custom built miniature water channel. This experimental characterization provides a first assessment of the feasibility of commercially available buoyant fluorescent beads in the analysis of high turbidity surface water flows. The proposed technology may serve as a minimally invasive sensing system for hazardous events, such as pollutant diffusion in natural streams and flash flooding due to extreme rainfall. PMID:22163540

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

    PubMed Central

    Herler, Jürgen; Dirnwöber, Markus

    2011-01-01

    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. PMID:22049248

  9. Estimating the neutrally buoyant energy density of a Rankine-cycle/fuel-cell underwater propulsion system

    NASA Astrophysics Data System (ADS)

    Waters, Daniel F.; Cadou, Christopher P.

    2014-02-01

    A unique requirement of underwater vehicles' power/energy systems is that they remain neutrally buoyant over the course of a mission. Previous work published in the Journal of Power Sources reported gross as opposed to neutrally-buoyant energy densities of an integrated solid oxide fuel cell/Rankine-cycle based power system based on the exothermic reaction of aluminum with seawater. This paper corrects this shortcoming by presenting a model for estimating system mass and using it to update the key findings of the original paper in the context of the neutral buoyancy requirement. It also presents an expanded sensitivity analysis to illustrate the influence of various design and modeling assumptions. While energy density is very sensitive to turbine efficiency (sensitivity coefficient in excess of 0.60), it is relatively insensitive to all other major design parameters (sensitivity coefficients < 0.15) like compressor efficiency, inlet water temperature, scaling methodology, etc. The neutral buoyancy requirement introduces a significant (?15%) energy density penalty but overall the system still appears to offer factors of five to eight improvements in energy density (i.e., vehicle range/endurance) over present battery-based technologies.

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

    NASA Astrophysics Data System (ADS)

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

    2010-01-01

    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.

  11. The vertical distribution of buoyant plastics at sea: an observational study in the North Atlantic Gyre

    NASA Astrophysics Data System (ADS)

    Reisser, J.; Slat, B.; Noble, K.; du Plessis, K.; Epp, M.; Proietti, M.; de Sonneville, J.; Becker, T.; Pattiaratchi, C.

    2015-02-01

    Millimetre-sized plastics are numerically abundant and widespread across the world's ocean surface. These buoyant macroscopic particles can be mixed within the upper water column by turbulent transport. Models indicate that the largest decrease in their concentration occurs within the first few metres of water, where in situ observations are very scarce. In order to investigate the depth profile and physical properties of buoyant plastic debris, we used a new type of multi-level trawl at 12 sites within the North Atlantic subtropical gyre to sample from the air-seawater interface to a depth of 5 m, at 0.5 m intervals. Our results show that plastic concentrations drop exponentially with water depth, and decay rates decrease with increasing Beaufort number. Furthermore, smaller pieces presented lower rise velocities and were more susceptible to vertical transport. This resulted in higher depth decays of plastic mass concentration (milligrams m-3) than numerical concentration (pieces m-3). Further multi-level sampling of plastics will improve our ability to predict at-sea plastic load, size distribution, drifting pattern, and impact on marine species and habitats.

  12. Buoyant Response of the Tank 241-SY-101 Crust to Transfer and Back-Dilution

    SciTech Connect

    CW Stewart

    1999-11-08

    The mixer pump installed in Hanford Tank 241-SY-101 (SY-101) in July 1993 has prevented the large buoyant displacement gas release events (BD GRE) it has historically exhibited. But the absence of periodic disruption from GREs and the action of mixing have allowed the crust to grow. The accelerated gas retention has resulted in over 30 inches of waste level growth and the flammable gas volume stored in the crust has become a hazard. To remediate gas retention in the crust and the potential for buoyant displacement gas releases from below the crust, SY-101 will be diluted in the fall of 1999 to dissolve a large fraction of the solids in the tank. The plan is to transfer waste out and back-dilute with water in several steps of about 100,000 gallons each. Back-dilution water may be added at the transfer pump inlet, the base of the mixer pump, and on top of the crust. The mixer pump will continue to be required to prevent formation of a deep nonconnective layer and resumption of BD GREs. Therefore, it is vital to ensure that the transfer and back-dilution processes do not significantly degrade the pump's effectiveness. Part of the strategy to avoid mixer pump degradation is to keep the base of the crust layer well above the pump inlet, which is 236 inches above the tank bottom. The maximum transfer for which an equal back-dilution is possible without sinking the crust is 90 kgal if water is injected at the 96-inch transfer pump inlet and 120 kgal for injection at the 9-inch mixer pump burrowing ring. To keep the crust base above the lowest observed elevation of 295 inches, transfer and back-dilution must be limited to 143 kgal and 80 kgal, respectively, for the 96-inch back-dilution and 175 kgal with a 112 kgal back-dilution using the 9-inch back-dilution elevation. These limits can be avoided by adding water to the top of the crust to dissolve the negatively buoyant layers. If 20 kgal of water is placed on top of the crust and the rest of the back-dilution is placed under the crust, back-dilution becomes limited by crust sinking at a 128 kgal transfer using the 96-inch injection point and at 160 kgal at 9 inches. The crust base remains well above the 295-inch minimum, and crust base elevation does not limit transfer volume. This result shows that top dilution is very beneficial in providing operational flexibility to the transfer and back-dilution process.

  13. Three-Dimensional Upward Flame Spreading in Partial-Gravity Buoyant Flows

    NASA Technical Reports Server (NTRS)

    Sacksteder, Kurt R.; Feier, Ioan I.; Shih, Hsin-Yi; T'ien, James S.

    2001-01-01

    Reduced-gravity environments have been used to establish low-speed, purely forced flows for both opposed- and concurrent-flow flame spread studies. Altenkirch's group obtained spacebased experimental results and developed unsteady, two-dimensional numerical simulations of opposed-flow flame spread including gas-phase radiation, primarily away from the flammability limit for thin fuels, but including observations of thick fuel quenching in quiescent environments. T'ien's group contributed some early flame spreading results for thin fuels both in opposed flow and concurrent flow regimes, with more focus on near-limit conditions. T'ien's group also developed two- and three-dimensional numerical simulations of concurrent-flow flame spread incorporating gas-phase radiative models, including predictions of a radiatively-induced quenching limit reached in very low-speed air flows. Radiative quenching has been subsequently observed in other studies of combustion in very low-speed flows including other flame spread investigations, droplet combustion and homogeneous diffusion flames, and is the subject of several contemporary studies reported in this workshop. Using NASA aircraft flying partial-gravity "parabolic" trajectories, flame spreading in purely buoyant, opposed-flow (downward burning) has been studied. These results indicated increases in flame spread rates and enhanced flammability (lower limiting atmospheric oxygen content) as gravity levels were reduced from normal Earth gravity, and were consistent with earlier data obtained by Altenkirch using a centrifuge. In this work, experimental results and a three-dimensional numerical simulation of upward flame spreading in variable partial-gravity environments were obtained including some effects of reduced pressure and variable sample width. The simulation provides physical insight for interpreting the experimental results and shows the intrinsic 3-D nature of buoyant, upward flame spreading. This study is intended to link the evolving understanding of flame spreading in purely-forced flows to the purely-buoyant flow environment, particularly in the concurrent flow regime; provide additional insight into the existence of steady flame spread in concurrent flows; and stimulate direct comparisons between opposed- and concurrent-flow flame spread. Additionally, this effort is intended to provide direct practical understanding applicable to fire protection planning for the habitable facilities in partial gravity environments of anticipated Lunar and Martian explorations.

  14. Wind and tidal forcing of a buoyant plume, Mobile Bay, Alabama

    USGS Publications Warehouse

    Stumpf, R.P.; Gelfenbaum, G.; Pennock, J.R.

    1993-01-01

    AVHRR satellite imagery and in situ observations were combined to study the motion of a buoyant plume at the mouth of Mobile Bay, Alabama. The plume extended up to 30 km from shore, with a thickness of about 1 m. The inner plume, which was 3-8 m thick, moved between the Bay and inner shelf in response to tidal forcing. The tidal prism could be identified through the movement of plume waters between satellite images. The plume responded rapidly to alongshore wind, with sections of the plume moving at speeds of more than 70 cm s-1, about 11% of the wind speed. The plume moved predominantly in the direction of the wind with a weak Ekman drift. The enhanced speed of the plume relative to normal surface drift is probably due to the strong stratification in the plume, which limits the transfer of momentum into the underlying ambient waters. ?? 1993.

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

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

    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.

  16. Remote Under-Ice Roving in Alaska with the Buoyant Rover for Under-Ice Exploration

    NASA Astrophysics Data System (ADS)

    Berisford, D. F.; Leichty, J.; Klesh, A.; Hand, K. P.

    2013-12-01

    The Buoyant Rover for Under-Ice Exploration (BRUIE) is two-wheeled robot capable of roving in two-dimensional space in the under-ice environment. The rover has positive buoyancy, allowing it to stick to the ice underside and operate using similar control principles as those used for traditional above-ground rovers. Recently added capability allows the rover to operate without a tether, communicating with a nearby above-ice ground station, which can relay data to a remote command center for remote operation. Additional upgrades include a dissolved methane sensor and improved capability for escape from entrapment in soft ice pockets. The system has been tested in thermokarst lakes near Barrow, Alaska, and data from onboard video and methane sensors gives scientific insight to the formation and distribution of trapped methane pockets in the lake ice. Here we present the updated design and preliminary data from deployments in the fall seasons of 2012 and 2013.

  17. Further studies on the relationship between platelet buoyant density and platelet age

    SciTech Connect

    Boneu, B.; Vigoni, F.; Boneu, A.; Caranobe, C.; Sie, P.

    1982-01-01

    The relationship between platelet buoyant density and platelet age was investigated in eight human subjects submitted to an autologous chromium labeled platelet survival study. Platelets were isolated after isopycnic centrifugation using eight discontinuous isoosmotic stractan gradients (five subjects), or various continuous and linear isoosmolar gradients (three subjects). A paradoxical radioactivity enrichment of the dense platelets and a premature loss of radioactivity in the light platelets were observed. These results are explained by a shift of the radioactivity distribution curve toward higher densities during the 3-4 days after platelet injection, while the standard deviation of the distribution was conserved throughout the platelet life span. These results suggest that young platelets are heterogeneous and slightly less dense than the total platelet population.

  18. Flow-field characteristics of high-temperature annular buoyant jets and their development laws influenced by ventilation system.

    PubMed

    Wang, Yi; Huang, Yanqiu; Liu, Jiaping; Wang, Hai; Liu, Qiuhan

    2013-01-01

    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. PMID:24000278

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

    PubMed Central

    Liu, Jiaping; Wang, Hai; Liu, Qiuhan

    2013-01-01

    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. PMID:24000278

  20. A comparison of the quantity and composition of material caught in a neutrally buoyant versus surface-tethered sediment trap

    Microsoft Academic Search

    Ken O. Buesseler; Deborah K. Steinberg; Anthony F. Michaels; Rodney J. Johnson; John E. Andrews; James R. Valdes; James F. Price

    2000-01-01

    The flux and composition of material caught using two different upper ocean sediment trap designs was compared at the Bermuda Atlantic Time-series Study site (BATS). The standard surface-tethered trap array at BATS was compared to a newly designed neutrally buoyant sediment trap (NBST). Both traps used identical cylindrical collection tubes. Of particular concern was the effect of horizontal flow on

  1. Mapping hydrothermal plumes in their rising and neutrally buoyant regimes with an autonomous underwater vehicle

    NASA Astrophysics Data System (ADS)

    Jakuba, M.; Yoerger, D.; Stahr, F.; McDuff, R.

    2004-12-01

    Propeller-driven autonomous underwater vehicles (AUVs) potentially enable unique perspectives on hydrothermal plumes that address both the temporal and spatial variability inherent in these structures. Like a lowered or profiling CTD, an AUV offers a platform capable of collecting multiple coregistered data; however, precise navigation and control of an AUV enables complex survey patterns and makes available the possibility of altering vehicle trajectory in real-time. We present data collected by the Autonomous Benthic Explorer (ABE) in June/July 2004 in both the buoyant and neutral components of hydrothermal plumes above the Main Endeavour Field, Juan de Fuca Ridge. The ABE recorded coregistered optical backscatter, temperature and conductivity from two vertically separated probe pairs, redox potential (eH), and water column current velocity from a doppler velocity log (DVL). Bottom-referenced vehicle velocity from the DVL and long baseline positioning enabled the water column velocities from the DVL to be accurately referenced to a stationary world frame. Despite the fact that background currents vary considerably over the course of a single AUV survey due to tidal effects, the use of water column velocity DVL data permits the recovery of better approximations to the time-varying structure of the tracer field in the plume. Using data from above the Juan de Fuca Ridge, we present several candidate triggers that could initiate autonomous behavior to increase survey resolution locally, for instance to improve the possibility of unabiguous detection of rising plume stems from within the neutrally buoyant plume. The envisioned adaptive strategy would result in precisely oriented fine-scale grids within the wider-spaced pre-defined survey. Such a strategy could provide an improvement in spatial resolution in critical regions of the plume without sacrificing the large-scale temporal resolution of the plume.

  2. The spatial distribution and speciation of iron in buoyant hydrothermal plumes of the Mid-Cayman Rise

    NASA Astrophysics Data System (ADS)

    Cron, B. R.; Toner, B. M.; Bennett, S. A.; German, C. R.; Dick, G.; Breier, J. A.

    2012-12-01

    Biogeochemical cycling of elements, such as iron and sulfur, at mid-ocean ridge spreading centers may modulate hydrothermal fluxes to the ocean. To better understand the nature and scale of these processes, the geochemical gradients in buoyant plumes were examined at the Mid-Cayman Rise, a short (~110 km) ultra-slow spreading center in the Caribbean Sea that hosts the deepest known high temperature venting. Changes in particulate iron and sulfur speciation were measured in the first 40-50 m of buoyant plumes at two vent fields, Von Damm (2,300m) and Piccard (5,000m). These data will be used to identify products of precipitation reactions and define particulate energy sources available for microbial metabolism. A series of samples were collected by in situ filtration at 0.5 m and 50 m above the Beebe Vents, Piccard hydrothermal field and at 1 m, 8 m, and 40 m above the central spire of the Von Damm vent field using the ROV Jason and CTD-casts. Samples were packaged under dinitrogen and frozen shipboard to preserve oxidation-reduction sensitive species for microprobe Fe 1s and S 1s X-ray absorption near edge structure (XANES) spectroscopy (Advanced Light Source, Lawrence Berkeley National Laboratory, beamline 10.3.2). The Von Damm vent is characterized by shimmering vent fluids with dilute particulates in the buoyant plume. Within the particulate phase, the Von Damm buoyant plume was comprised of 38 mol % Fe-sulfides, 40 mol % Fe(II), and 21 mol % Fe(III) at 1 m. At 8 m it is comprised of 32 mol % Fe-sulfides, 7 % Fe(II), and 59 mol % Fe(III). When the plume reaches 40 m, it is 6 mol % Fe-sulfides, 8 mol % Fe(II), 72 mol % Fe(III), and 14 mol % Fe(0). The Beebe vents are characterized by very dense particle formation in their buoyant plumes. The Beebe vent plume sampled comprised 65 mol % sulfides, 3 % mol Fe(II) & 32 mol % Fe(III)¬¬¬¬ at 0.5 m. As the plume reached 50 m above the vent, the fluids were 43 mol % sulfide and 56 mol % Fe(III). Both buoyant plume samples were dominated by reduced iron species that rapidly become more oxidized as they reacted with deep-sea water entrained into the plume. The next steps for this study are to quantify iron and sulfur species in the plumes, and identify the microbial communities that are closely associated with particulate iron and sulfur using fluorescent in situ hybridization (FISH).

  3. Dispersal of volcaniclasts during deep-sea eruptions: Settling velocities and entrainment in buoyant seawater plumes

    NASA Astrophysics Data System (ADS)

    Barreyre, Thibaut; Soule, S. Adam; Sohn, Robert A.

    2011-08-01

    We use tank experiments to measure settling rates of deep-sea volcaniclastic material recovered from the Arctic (85°E Gakkel Ridge) and Pacific (Juan de Fuca Ridge, Loihi seamount) Oceans. We find that clast size and shape exert a strong influence on settling velocity, with velocities of ~ 30 cm/s for large (~ 8 mm), blocky clasts, compared to velocities of ~ 2.5 cm/s for small (< 0.5 mm), sheet-like clasts. We fit our observations to the generalized model of Ferguson and Church (2004) to establish empirical scaling laws for settling velocity, and then use these results to test the hypothesis that entrainment in a buoyant plume of hot seawater is an important dispersal mechanism for volcaniclastic material in the deep-sea (Clague et al., 2009). We superpose the observed settling rates on velocity fields generated with the Morton et al. (1956) model for turbulent plumes in stratified media to estimate the rise height of the clastic material under water column conditions corresponding to the Gakkel and Juan de Fuca (JdFR) Ridges, and then estimate dispersal distances assuming the grains settle to the seafloor while being advected in lateral currents. Dispersal distances in our model are a function plume strength (i.e., buoyancy flux), lateral current speeds, and clast settling velocity. Our model demonstrates that large (30 GW) eruption 'megaplumes' can loft volcaniclastic material more than a kilometer above the seafloor where entrainment in deep-sea currents can advect dominant clast types (~ 1 mm, blocky grains) up to a few hundred meters from a source vent. Small bubble-wall fragments (e.g., limu o Pele) entrained in a megaplume could be advected as far as a few kilometers from a source region. These results indicate that entrainment in buoyant seawater plumes during an eruption may play an important role in clast dispersal, but it is not clear if this mechanism can explain the distribution of volcaniclastic material at the sites on the Gakkel and Juan de Fuca Ridges where our samples were acquired. In order to understand the dispersal of volcaniclastic material in the deep-sea it will be necessary to rigorously characterize existing deposits, and develop models capable of incorporating explosive gas phases into the eruption plume.

  4. Reexamination of the Association Between Melting Point, Buoyant Density, and Chemical Base Composition of Deoxyribonucleic Acid

    PubMed Central

    De Ley, J.

    1970-01-01

    The equations currently used for the calculation of the chemical base composition of deoxyribonucleic acid (DNA), expressed as moles per cent guanine plus cytosine (% GC), from either buoyant density (?) or midpoint of thermal denaturation (Tm) were recalculated by using only sets of data on DNA determined with the same strains. All available information from the literature was screened and supplemented by unpublished data. The results were calculated by regression and correlation analysis and treated statistically. From the data on 96 strains of bacteria, it was calculated that% GC = 2.44 (Tm – 69.4). Tm appears to be unaffected by the substitution of cytosine by hydroxymethylcytosine. This equation is also valid for nonbacterial DNA. From the data on 84 strains of bacteria, the relation% GC = 1038.47 (–1.6616) was calculated. The constants in this equation are slightly modified when data on nonbacterial DNA are included. Both correlations differ only slightly from those currently used, but now they lean on a statistically sound basis. As a control, the relation between ? and Tm was calculated from data of 197 strains; it agrees excellently with the above two equations. PMID:5438045

  5. Buoyant instabilities in downward flow in a symmetrically heated vertical channel

    SciTech Connect

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

    1996-07-01

    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.

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

    PubMed

    Vahidi, Bahman; Fatouraee, Nasser

    2012-04-30

    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

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

    NASA Astrophysics Data System (ADS)

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

    2010-08-01

    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.

  8. Isolation of Rare Tumor Cells from Blood Cells with Buoyant Immuno-Microbubbles

    PubMed Central

    Shi, Guixin; Cui, Wenjin; Benchimol, Michael; Liu, Yu-Tsueng; Mattrey, Robert F.; Mukthavaram, Rajesh; Kesari, Santosh; Esener, Sadik C.; Simberg, Dmitri

    2013-01-01

    Circulating tumor cells (CTCs) are exfoliated at various stages of cancer, and could provide invaluable information for the diagnosis and prognosis of cancers. There is an urgent need for the development of cost-efficient and scalable technologies for rare CTC enrichment from blood. Here we report a novel method for isolation of rare tumor cells from excess of blood cells using gas-filled buoyant immuno-microbubbles (MBs). MBs were prepared by emulsification of perfluorocarbon gas in phospholipids and decorated with anti-epithelial cell adhesion molecule (EpCAM) antibody. EpCAM-targeted MBs efficiently (85%) and rapidly (within 15 minutes) bound to various epithelial tumor cells suspended in cell medium. EpCAM-targeted MBs efficiently (88%) isolated frequent tumor cells that were spiked at 100,000 cells/ml into plasma-depleted blood. Anti-EpCAM MBs efficiently (>77%) isolated rare mouse breast 4T1, human prostate PC-3 and pancreatic cancer BxPC-3 cells spiked into 1, 3 and 7 ml (respectively) of plasma-depleted blood. Using EpCAM targeted MBs CTCs from metastatic cancer patients were isolated, suggesting that this technique could be developed into a valuable clinical tool for isolation, enumeration and analysis of rare cells. PMID:23516425

  9. Buoyant flexure and basal crevassing in dynamic mass loss at Helheim Glacier

    NASA Astrophysics Data System (ADS)

    James, Timothy D.; Murray, Tavi; Selmes, Nick; Scharrer, Kilian; O'Leary, Martin

    2014-08-01

    Iceberg calving accounts for a significant proportion of annual mass loss from marine-terminating glaciers and may have been a factor in the rapid demise of ancient ice sheets. The largest contributions from the main outlet glaciers of the Greenland ice sheet to sea-level rise over the next two centuries have been projected to be dynamic in origin, that is, driven by glacier flow and calving. However, present physical models remain a coarse approximation of real calving mechanisms because models are poorly constrained by sparse glacier geometry observations. Here we present a record of daily digital elevation models from the calving margin of Greenland’s Helheim Glacier at a high spatial resolution. Our digital elevation models are derived from stereo terrestrial photography taken over the summers of 2010 and 2011. We find that during these two summers dynamic mass loss at Helheim Glacier was dominated by calving events exceeding 1 km3 that were the result of buoyant flexure and the propagation of basal crevasses. We suggest that this buoyancy-driven mechanism for calving may be common elsewhere in Greenland and could be a first-order control on the ice sheet’s future contribution to sea-level rise.

  10. Flame Shapes of Luminous NonBuoyant Laminar Coflowing Jet Diffusion Flames

    NASA Technical Reports Server (NTRS)

    Lin, K.-C.; Faeth, G. M.

    1999-01-01

    Laminar diffusion flames are of interest as model flame systems that are more tractable for analysis and experiments than practical turbulent diffusion flames. Certainly understanding laminar flames must precede understanding more complex turbulent flames while man'y laminar diffusion flame properties are directly relevant to turbulent diffusion flames using laminar flamelet concepts. Laminar diffusion flame shapes have been of interest since the classical study of Burke and Schumann because they involve a simple nonintrusive measurement that is convenient for evaluating flame structure predictions. Motivated by these observations, the shapes of laminar flames were considered during the present investigation. The present study was limited to nonbuoyant flames because most practical flames are not buoyant. Effects of buoyancy were minimized by observing flames having large flow velocities at small pressures. Present methods were based on the study of the shapes of nonbu,3yant round laminar jet diffusion flames of Lin et al. where it was found that a simple analysis due to Spalding yielded good predictions of the flame shapes reported by Urban et al. and Sunderland et al.

  11. Near Surface Vapor Bubble Layers in Buoyant Low Stretch Burning of Polymethylmethacrylate

    NASA Technical Reports Server (NTRS)

    Olson, Sandra L.; Tien, J. S.

    1999-01-01

    Large-scale buoyant low stretch stagnation point diffusion flames over solid fuel (polymethylmethacrylate) were studied for a range of aerodynamic stretch rates of 2-12/ sec which are of the same order as spacecraft ventilation-induced stretch in a microgravity environment. An extensive layer of polymer material above the glass transition temperature is observed. Unique phenomena associated with this extensive glass layer included substantial swelling of the burning surface, in-depth bubble formation, and migration and/or elongation of the bubbles normal to the hot surface. The bubble layer acted to insulate the polymer surface by reducing the effective conductivity of the solid. The reduced in-depth conduction stabilized the flame for longer than expected from theory neglecting the bubble layer. While buoyancy acts to move the bubbles deeper into the molten polymer, thermocapillary forces and surface regression both act to bring the bubbles to the burning surface. Bubble layers may thus be very important in low gravity (low stretch) burning of materials. As bubbles reached the burning surface, monomer fuel vapors jetted from the surface, enhancing burning by entraining ambient air flow. Popping of these bubbles at the surface can expel burning droplets of the molten material, which may increase the fire propagation hazards at low stretch rates.

  12. 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

    2011-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-3a Materials—Dee ring and snap hook assemblies and other instruments of...

  13. 46 CFR 160.060-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-3a Materials—Dee ring and snap hook assemblies and other instruments of...

  14. 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

    2012-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-3a Materials—Dee ring and snap hook assemblies and other instruments of...

  15. 46 CFR 160.060-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-3a Materials—Dee ring and snap hook assemblies and other instruments of...

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

    SciTech Connect

    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

    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.

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

    PubMed Central

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

    2013-01-01

    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. PMID:23894421

  18. Numerical and experimental modeling of VGF-type buoyant flow under the influence of traveling and rotating magnetic fields

    NASA Astrophysics Data System (ADS)

    Galindo, V.; Niemietz, K.; Pätzold, O.; Gerbeth, G.

    2012-12-01

    Numerical and experimental modeling of a VGF-type (VGF—vertical gradient freeze) buoyant flow under the influence of both traveling and rotating magnetic fields (TMF and RMF, respectively) is presented. Low-temperature flow experiments were carried out using a GaInSn alloy as model fluid. Radial heating and cooling of the melt leading to a meridional double vortex flow like in typical VGF growth was introduced using a double-walled melt container. The flow was found to be significantly influenced by the mutual interaction of buoyant and electromagnetically driven forces. With increasing axial temperature difference, the buoyant flow becomes more concentrated in the upper and lower part of the melt leaving an extended melt zone with low flow velocity around the mid-height. Furthermore, VGF-type buoyancy is found to stabilize TMF- and RMF-induced melt flows. Besides, the time evolution of the flow just above the stability threshold is studied. In the case of combined VGF-type/RMF flow complex fluctuation patterns are observed, which depends sensitively on the applied thermal field.

  19. Design and evaluation of hydrophobic coated buoyant core as floating drug delivery system for sustained release of cisapride

    PubMed Central

    Jacob, Shery; Nair, Anroop B; Patil, Pandurang N

    2010-01-01

    An inert hydrophobic buoyant coated–core was developed as floating drug delivery system (FDDS) for sustained release of cisapride using direct compression technology. Core contained low density, porous ethyl cellulose, which was coated with an impermeable, insoluble hydrophobic coating polymer such as rosin. It was further seal coated with low viscosity hydroxypropyl methyl cellulose (HPMC E15) to minimize moisture permeation and better adhesion with an outer drug layer. It was found that stable buoyant core was sufficient to float the tablet more than 8 h without the aid of sodium bicarbonate and citric acid. Sustained release of cisapride was achieved with HPMC K4M in the outer drug layer. The floating lag time required for these novel FDDS was found to be zero, however it is likely that the porosity or density of the core is critical for floatability of these tablets. The in vitro release pattern of these tablets in simulated gastric fluid showed the constant and controlled release for prolonged time. It can be concluded that the hydrophobic coated buoyant core could be used as FDDS for gastroretentive delivery system of cisapride or other suitable drugs. PMID:24825997

  20. Conduit diameter and buoyant rising speed of mantle plumes: Implications for the motion of hot spots and shape of plume conduits

    Microsoft Academic Search

    B. Steinberger; M. Antretter

    2006-01-01

    Mantle plumes are expected to be affected by large-scale flow in the Earth's mantle related to plate motions, subducted slabs, and possibly large-scale upwellings. Motion of plume conduits will depend on both large-scale flow and buoyant rising speed of the conduit through the mantle. Here we present a model of depth-dependent plume conduit temperature, viscosity, radius, and buoyant rising speed

  1. Temperature Versus Buoyant Mantle Heterogeneities, Evaluating the Origin of OIB Using the Galapagos Archipelago

    NASA Astrophysics Data System (ADS)

    Saal, A. E.; Bourdon, B.; Kurz, M. D.; Hauri, E. H.; Blusztajn, J.; Blichert-Toft, J.; Hart, S. R.; Sims, K. W.

    2007-12-01

    The existence of hot mantle plumes has recently been questioned; instead tectonics and shallow low-melting heterogeneities, rather than excess temperatures, have been proposed to explain the upwelling of mantle beneath oceanic islands basalts (OIB) [1]. Geophysical, petrological and geochemical arguments have been used to suggest that enriched heterogeneities located shallow within the upper mantle are buoyant due to either melt retention or water lowering its solidus and consequently triggering early melting of the fertile blobs. Thus, the opponents of the hotspot model have suggested that shallow fertile and buoyant blobs could reproduce the effects of temperature, including isotope gradients, as the cause for the generation of OIB [1]. Uranium-series disequilibria measured in oceanic lavas may provide insight into the origin of OIB that is independent of previous arguments. Earlier works have shown that U-series isotopes in basalts are sensitive to variations in the upwelling rates of their mantle source, and those can be used to invoke upward movements that may be associated with mantle plumes [2-4]. Those work also demonstrated that there exist a significant relationship between the extent of U-series disequilibria and the buoyancy flux beneath OIB; where lower buoyancy fluxes are associated with lower rates of melting and hence higher (230Th/238U) values [2]. However, most of those works have assumed that the effects of source heterogeneity can be neglected relative to the effects of other key parameters. If the increase in melting rates is truly due to the presence of fertile blobs, then there should be a correlation between clear indices of enrichment such as radiogenic isotopes and extent of U-series disequilibrium in OIB. Furthermore, the fertility of the mantle heterogeneities may or may not be associated with the enrichment of water, which has an important effect on the melting rate and consequently in the U-series isotope of the basalts. To evaluate what factors (temperature versus mantle heterogeneity) are controlling the upwelling mantle beneath oceanic islands we used our data (including volatile and U-series isotopes) for lavas from across the Galapagos archipelago combined with previously published results from the adjacent Galapagos Spreading Ridge lavas [5]. These results suggest that the most important factor controlling the variation in mantle upwelling velocities beneath the Galapagos archipelago and adjacent ridge is the difference in mantle temperature. References 1. Plates, Plumes, and Paradigms (eds Foulger, G.R., Natland, J.H., Presnall, D.C. & Anderson, D.L.) (GSA Special Paper 388, Geological Society of America, Boulder, 2005). 2. Bourdon, B. et al. Nature 444, 713-717, 10.1038 (2006). 3. Bourdon, B. & Sims, K. W. W. in U-series Geochemistry (eds Bourdon, B., Lundstrom, C., Henderson, G. & Turner, S. P.) 215-253 (Mineralogical Society of America, 2003).

  2. Extinction and Scattering Properties of Soot Emitted from Buoyant Turbulent Diffusion Flames. Appendix F

    NASA Technical Reports Server (NTRS)

    Krishnan, S. S.; Lin, K.-C.; Faeth, G. M.; Yuan, Z.-G. (Technical Monitor); Urban, D. L. (Technical Monitor); Yuan, Z.-G. (Technical Monitor)

    2001-01-01

    Extinction and scattering properties at wavelengths of 250-5200 nm were studied for soot emitted from buoyant turbulent diffusion flames in the long residence time regime where soot properties are independent of position in the overfire region and characteristic flame residence times. Flames burning in still air and fueled with gas (acetylene, ethylene, propane, and propylene) and liquid (benzene, toluene, cyclohexane, and n-heptane) hydrocarbon fuels were considered. Measured scattering patterns and ratios of total scattering/absorption cross sections were in good agreement with predictions based on the Rayleigh-Debye-Gans (RDG) scattering approximation in the visible. Measured depolarization ratios were roughly correlated by primary particle size parameter, suggesting potential for completing RDG methodology needed to make soot scattering predictions as well as providing a nonintrusive way to measure primary soot particle diameters. Measurements of dimensionless extinction coefficients were in good agreement with earlier measurements for similar soot populations and were independent of fuel type and wavelength except for reduced values as the near ultraviolet was approached. The ratios of the scattering/absorption refractive index functions were independent of fuel type within experimental uncertainties and were in good agreement with earlier measurements. The refractive index junction for absorption was similarly independent of fuel type but was larger than earlier reflectometry measurements in the infrared. Ratios of total scattering/absorption cross sections were relatively large in the visible and near infrared, with maximum values as large as 0.9 and with values as large as 0.2 at 2000 nm, suggesting greater potential for scattering from soot particles to affect flame radiation properties than previously thought.

  3. Extinction and Scattering Properties of Soot Emitted from Buoyant Turbulent Diffusion Flames. Appendix D

    NASA Technical Reports Server (NTRS)

    Krishnan, S. S.; Lin, K.-C.; Faeth, G. M.; Urban, D. L. (Technical Monitor); Yuan, Z.-G. (Technical Monitor)

    2001-01-01

    Extinction and scattering properties at wavelengths of 250-5200 nm were studied for soot emitted from buoyant turbulent diffusion flames in the long residence time regime where soot properties are independent of position in the overfire region and characteristic flame residence times. Flames burning in still air and fueled with gas (acetylene, ethylene, propane, and propylene) and liquid (benzene, toluene, cyclohexane, and n-heptane) hydrocarbon fuels were considered Measured scattering patterns and ratios of total scattering/absorption cross sections were in good agreement with predictions based on the Rayleigh-Debye-Gans (RDG) scattering approximation in the visible. Measured depolarization ratios were roughly correlated by primary particle size parameter, suggesting potential for completing RDG methodology needed to make soot scattering predictions as well as providing a nonintrusive way to measure primary soot particle diameters. Measurements of dimensionless extinction coefficients were in good agreement with earlier measurements for similar soot populations and were independent of fuel type and wavelength except for reduced values as the near ultraviolet was approached. The ratios of the scattering/absorption refractive index functions were independent of fuel type within experimental uncertainties and were in good agreement with earlier measurements. The refractive index function for absorption was similarly independent of fuel type but was larger than earlier reflectometry measurements in the infrared. Ratios of total scattering/absorption cross sections were relatively large in the visible and near infrared, with maximum values as large as 0.9 and with values as large as 0.2 at 2000 nm, suggesting greater potential for scattering from soot particles to affect flame radiation properties than previously thought.

  4. Experimental investigation of turbulent diffusion of slightly buoyant droplets in locally isotropic turbulence

    NASA Astrophysics Data System (ADS)

    Gopalan, Balaji; Malkiel, Edwin; Katz, Joseph

    2008-09-01

    High-speed inline digital holographic cinematography is used for studying turbulent diffusion of slightly buoyant 0.5-1.2 mm diameter diesel droplets and 50 ?m diameter neutral density particles. Experiments are performed in a 50×50×70 mm3 sample volume in a controlled, nearly isotropic turbulence facility, which is characterized by two dimensional particle image velocimetry. An automated tracking program has been used for measuring velocity time history of more than 17 000 droplets and 15 000 particles. For most of the present conditions, rms values of horizontal droplet velocity exceed those of the fluid. The rms values of droplet vertical velocity are higher than those of the fluid only for the highest turbulence level. The turbulent diffusion coefficient is calculated by integration of the ensemble-averaged Lagrangian velocity autocovariance. Trends of the asymptotic droplet diffusion coefficient are examined by noting that it can be viewed as a product of a mean square velocity and a diffusion time scale. To compare the effects of turbulence and buoyancy, the turbulence intensity (ui') is scaled by the droplet quiescent rise velocity (Uq). The droplet diffusion coefficients in horizontal and vertical directions are lower than those of the fluid at low normalized turbulence intensity, but exceed it with increasing normalized turbulence intensity. For most of the present conditions the droplet horizontal diffusion coefficient is higher than the vertical diffusion coefficient, consistent with trends of the droplet velocity fluctuations and in contrast to the trends of the diffusion timescales. The droplet diffusion coefficients scaled by the product of turbulence intensity and an integral length scale are a monotonically increasing function of ui'/Uq.

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

    USGS Publications Warehouse

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

    2009-01-01

    During the upwelling season in central California, northwesterly winds along the coast produce a strong upwelling jet that originates at Point A??o 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 A??o 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.Copyright 2009 by the American Geophysical Union.

  6. Deformation statistics of sub-Kolmogorov-scale ellipsoidal neutrally buoyant drops in isotropic turbulence

    E-print Network

    Luca Biferale; Charles Meneveau; Roberto Verzicco

    2015-02-12

    Small droplets in turbulent flows can undergo highly variable deformations and orientational dynamics. For neutrally buoyant droplets smaller than the Kolmogorov scale, the dominant effects from the surrounding turbulent flow arise through Lagrangian time histories of the velocity gradient tensor. Here we study the evolution of representative droplets using a model that includes rotation and stretching effects from the surrounding fluid, and restoration effects from surface tension including a constant droplet volume constraint, while assuming that the droplets maintain an ellipsoidal shape. The model is combined with Lagrangian time histories of the velocity gradient tensor extracted from DNS of turbulence to obtain simulated droplet evolutions. These are used to characterize the size, shape and orientation statistics of small droplets in turbulence. A critical capillary number, $Ca_c$ is identified associated with unbounded growth of one or two of the droplet's semi-axes. Exploiting analogies with dynamics of polymers in turbulence, the $Ca_c$ number can be predicted based on the large deviation theory for the largest Finite Time Lyapunov exponent. Also, for sub-critical $Ca$ the theory enables predictions of the slope of the power-law tails of droplet size distributions in turbulence. For cases when the viscosities of droplet and outer fluid differ in a way that enables vorticity to decorrelate the shape from the straining directions, the large deviation formalism based on the stretching properties of the velocity gradient tensor loses validity and its predictions fail. Even considering the limitations of the assumed ellipsoidal droplet shape, the results highlight the complex coupling between droplet deformation, orientation and the local fluid velocity gradient tensor to be expected when small viscous drops interact with turbulent flows.

  7. Toward the Understanding and Optimization of Chimneys for Buoyantly Driven Biomass Stoves

    NASA Astrophysics Data System (ADS)

    Prapas, Jason

    The vast majority of indoor combustion devices in the developed world make use of stacks (flues, vents, chimneys, smokestacks) to channel flue gases out of the operator space. In the developing world, where indoor air pollution kills several million people every year, the use of chimneys with biomass cooking and heating stoves has been met with limited success and a high level of controversy. Due to a lack of theoretical understanding, design criteria, poorly executed installation practices, and/or insufficient maintenance routines, many chimney stoves have exhibited inadequate indoor emissions reductions in addition to low thermal efficiencies. This work aims (a) shed light on the physical phenomenon of the "stack effect" as it pertains to dynamic, non-adiabatic, buoyancy-driven stoves (b) apply new understanding toward the optimization of two types of biomass chimney stoves: plancha or griddle type stoves popular in Central America and two-pot stoves common in South America. A numerical heat and fluid flow model was developed that takes into account the highly-coupled variables and dynamic nature of such systems. With a comprehensive physical model, parameter studies were conducted to determine how several field-relevant variables influence the performance of stack-outfitted systems. These parameters include, but are not limited to: power/wood consumption rate, chimney geometry, stove geometry, material properties, heat transfer, and ambient conditions. An instrumented experimental chimney was built to monitor relationships between air flow, differential pressure, gas temperatures, emissions, and thermal efficiency. The draft provided by chimneys was found to have a strong influence over the bulk air-to-fuel ratio of buoyantly-driven cookstoves, greatly affecting the stove's overall performance by affecting gas temperatures, emissions, and efficiency. Armed with new information from the modeling and experimental work, two new stoves were designed and optimized to have significant reductions in fuel use and emissions.

  8. Vortex-induced vibrations of a neutrally buoyant circular cylinder near a plane wall

    NASA Astrophysics Data System (ADS)

    Wang, X. K.; Hao, Z.; Tan, S. K.

    2013-05-01

    This paper presents an experimental study of the motions, drag force and vortex shedding patterns of an elastically mounted circular cylinder, which is held at various heights above a plane wall and is subject to vortex-induced vibration (VIV) in the transverse direction. The cylinder is neutrally buoyant with a mass ratio m=1.0 and has a low damping ratio ?=0.0173. Effects of the gap ratio (S/D) ranged from 0.05 to 2.5 and the free-stream velocity (U) ranged from 0.15 to 0.65m/s (corresponding to 3000?Re?13 000, and 1.53?U?6.62) are examined. The flow around the cylinder has been measured using particle image velocimetry (PIV), in conjunction with direct measurements of the dynamic drag force on the cylinder using a piezoelectric load cell. Results of the vibrating cylinder under unbounded (or free-standing) condition, as well as those of a near-wall stationary cylinder at the same gap ratios, are also provided. For the free-standing cylinder, the transition from the initial branch to the upper branch is characterized by a switch of vortex pattern from the classical 2S mode to the newly-discovered 2PO mode by Morse and Williamson (2009). The nearby wall not only affects the amplitude and frequency of vibration, but also leads to non-linearities in the cylinder response as evidenced by the presence of super-harmonics in the drag force spectrum. In contrast to the case of a stationary cylinder that vortex shedding is suppressed below a critical gap ratio (S/D?0.3), the elastically mounted cylinder always vibrates even at the smallest gap ratio S/D=0.05. Due to the proximity of the plane wall, the vortices shed from the vibrating cylinder that would otherwise be in a double-sided vortex street pattern (either 2S or 2PO mode) under free-standing condition are arranged into a single-sided pattern.

  9. The influence of buoyant convection on the nucleation of n-propanol in thermal diffusion cloud chambers

    NASA Astrophysics Data System (ADS)

    Ferguson, Frank T.; Heist, Richard H.; Nuth, Joseph A.

    2010-05-01

    A two-dimensional numerical model has been applied to three thermal diffusion cloud chamber (TDCC) investigations of n-propanol in helium taken by two different research groups to provide a quantitative example of how the results in these chambers can be affected by buoyant convection. In the first set of TDCC data, corrections for buoyancy resolve an apparent discontinuity in critical supersaturation data and also yield nucleation rate data that tend to agree better with higher rate, expansion-based studies at the same temperature. In the second TDCC study, the nucleation of propanol was studied over an extended pressure range. When the model was applied to these data, the possible variation in supersaturation values due to convection induced by conditions at the chamber sidewall was found to be comparable in magnitude to the experimentally observed range and may be responsible for some of this observed pressure dependence. In the third TDCC study, the combination of an error in a transport property and buoyant convection appear responsible for a perceived pressure effect in the experimental data. After correcting for this transport property and for buoyancy, the results at higher temperatures agree quite closely with the predictions of classical nucleation theory.

  10. Synthesis of buoyant metal-coated fly ash cenosphere and its excellent catalytic performance in dye degradation.

    PubMed

    Wang, Wei; Zhai, Jianping; Li, Qin

    2015-04-15

    In this work, Ag(+) and Ag(0) were absorbed onto the surface of 3-mercaptopropyltriethoxysilane modified fly ash cenospheres (FACs) in two Ag activation processes. The activation methods, avoiding traditional surface sensitization by SnCl2, successfully initiated electroless copper particles deposition for the preparation of buoyant Cu-FAC and CuAg-FAC composites. The CuAg-FAC had a much more uniform morphology than the Cu-FAC. The catalytic performance of the Cu-FAC and CuAg-FAC was examined by the reduction of Orange IV azo dye with the presence of NaBH4. 98.4% of Orange IV was rapidly reduced within 25 min by the CuAg-FAC, whereas 76.4% of Orange IV was removed by the Cu-FAC. The results reveal that the degradation processes matched well with the pseudo-first-order kinetics model, and rate constants of 0.057 and 0.186 min(-1) were obtained for the Cu-FAC and CuAg-FAC, respectively. Moreover, two other dyes of Orange II and Reactive Black 5 were also efficiently reduced by the CuAg-FAC which could be easily recycled and stably reused at least four times. These buoyant metal-coated FAC composites would be very useful in various catalytic reductions. PMID:25585281

  11. The influence of buoyant convection on the nucleation of n-propanol in thermal diffusion cloud chambers.

    PubMed

    Ferguson, Frank T; Heist, Richard H; Nuth, Joseph A

    2010-05-28

    A two-dimensional numerical model has been applied to three thermal diffusion cloud chamber (TDCC) investigations of n-propanol in helium taken by two different research groups to provide a quantitative example of how the results in these chambers can be affected by buoyant convection. In the first set of TDCC data, corrections for buoyancy resolve an apparent discontinuity in critical supersaturation data and also yield nucleation rate data that tend to agree better with higher rate, expansion-based studies at the same temperature. In the second TDCC study, the nucleation of propanol was studied over an extended pressure range. When the model was applied to these data, the possible variation in supersaturation values due to convection induced by conditions at the chamber sidewall was found to be comparable in magnitude to the experimentally observed range and may be responsible for some of this observed pressure dependence. In the third TDCC study, the combination of an error in a transport property and buoyant convection appear responsible for a perceived pressure effect in the experimental data. After correcting for this transport property and for buoyancy, the results at higher temperatures agree quite closely with the predictions of classical nucleation theory. PMID:20515103

  12. Mixing of a chemically buoyant layer at the top of a thermally convecting fluid: Implications for mantle dynamics with application to Venus

    NASA Technical Reports Server (NTRS)

    Parmentier, E. M.; Hess, P. C.; Sotin, C.

    1993-01-01

    Partial melting to generate the crust of a planet can create a buoyant residual layer at the top of the mantle which may have important implications for episodic planetary evolution. However, the rate of mixing of such a chemically buoyant layer with a thermally convecting mantle is an important unresolved question. Except for a few laboratory and numerical studies designed to address questions related to convection in the Earth's mantle, previous studies have generally treated on the mixing of passive tracers. The inhibiting role of chemical buoyancy on mixing is intuitively obvious but not fully understood quantitatively. In this study, we examine the dynamics of an intrinsically buoyant fluid layer at the top of a deeper, thermally convecting, infinite Prandtl number fluid that is heated from below.

  13. Modeling the buoyant flow of heated water discharged from surface and submerged side outfalls in shallow and deep water with a cross flow

    Microsoft Academic Search

    Dae Geun Kim; Hong Yeun Cho

    2006-01-01

    In this study, a three-dimensional model was used to numerically study the buoyant flow, along with its mixing characteristics, of heated water discharged from the surface and submerged side outfalls in shallow and deep water with a cross flow. Hydraulic experimental data were used to evaluate the applicability of the model. The simulation results agree well with the experimental results,

  14. Hands-on experiences with buoyant-less water This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-print Network

    Planin�iè, Gorazd

    tossed bottle filled with water with a small, inflated balloon attached to the bottom by a spring, if water happens to be in a free-falling bottle, it would be weightless and would behave in a way whichHands-on experiences with buoyant-less water This article has been downloaded from IOPscience

  15. Oscillating motions of neutrally buoyant particle and red blood cell in Poiseuille flow in a narrow channel

    NASA Astrophysics Data System (ADS)

    Shi, Lingling; Yu, Yao; Pan, Tsorng-Whay; Glowinski, Roland

    2014-04-01

    Two motions of oscillation and vacillating breathing (swing) of red blood cell with a stiffened membrane have been observed in bounded Poiseuille flows [L. Shi, T.-W. Pan, and R. Glowinski, "Deformation of a single blood cell in bounded Poiseuille flows," Phys. Rev. E 85, 16307 (2012)]. To understand such motions, we have compared them with the oscillating motion of a neutrally buoyant particle of the same shape in Poiseuille flow in a narrow channel since a suspended cell is actually a neutrally buoyant entity. In a narrow channel, the particle can be held in the central region for a while with its mass center moving up and down if it is placed at the centerline initially. Its inclination angle oscillates at the beginning; but its range of oscillation keeps increasing and at the end the particle tumbles when the particle migrates away from the centerline due to the inertia effect. When the particle mass center is restricted to move only on the channel centerline, the inclination angle has been locked to a fixed angle without oscillation. Since the mass center of a deformable cell always migrates toward the channel central region in Poiseuille flow, its inclination angle behaves similar to the aforementioned oscillating motion of the particle as long as the cell keeps the long body shape and moves up and down. But when the up-and-down oscillation of the cell mass center damps out, the oscillating motion of the inclination angle also damps out and the cell inclination angle also approaches to a fixed angle.

  16. A field evaluation of an external and neutrally buoyant acoustic transmitter for juvenile salmon: implications for estimating hydroturbine passage survival.

    PubMed

    Brown, Richard S; Deng, Z Daniel; Cook, Katrina V; Pflugrath, Brett D; Li, Xinya; Fu, Tao; Martinez, Jayson J; Li, Huidong; Trumbo, Bradly A; Ahmann, Martin L; Seaburg, Adam G

    2013-01-01

    Turbine-passed fish are exposed to rapid decreases in pressure which can cause barotrauma. The presence of an implanted telemetry tag increases the likelihood of injury or death from exposure to pressure changes, thus potentially biasing studies evaluating survival of turbine-passed fish. Therefore, a neutrally buoyant externally attached tag was developed to eliminate this bias in turbine passage studies. This new tag was designed not to add excess mass in water or take up space in the coelom, having an effective tag burden of zero with the goal of reducing pressure related biases to turbine survival studies. To determine if this new tag affects fish performance or susceptibility to predation, it was evaluated in the field relative to internally implanted acoustic transmitters (JSATS; Juvenile Salmon Acoustic Telemetry System) used widely for survival studies of juvenile salmonids. Survival and travel time through the study reach was compared between fish with either tag type in an area of high predation in the Snake and Columbia rivers, Washington. An additional group of fish affixed with neutrally-buoyant dummy external tags were implanted with passive integrated transponder (PIT) tags and recovered further downstream to assess external tag retention and injury. There were no significant differences in survival to the first detection site, 12 river kilometers (rkm) downstream of release. Travel times were also similar between groups. Conversely, externally-tagged fish had reduced survival (or elevated tag loss) to the second detection site, 65 rkm downstream. In addition, the retention study revealed that tag loss was first observed in fish recaptured approximately 9 days after release. Results suggest that this new tag may be viable for short term (<8 days) single-dam turbine-passage studies and under these situations, may alleviate the turbine passage-related bias encountered when using internal tags, however further research is needed to confirm this. PMID:24204947

  17. A Field Evaluation of an External and Neutrally Buoyant Acoustic Transmitter for Juvenile Salmon: Implications for Estimating Hydroturbine Passage Survival

    PubMed Central

    Brown, Richard S.; Deng, Z. Daniel; Cook, Katrina V.; Pflugrath, Brett D.; Li, Xinya; Fu, Tao; Martinez, Jayson J.; Li, Huidong; Trumbo, Bradly A.; Ahmann, Martin L.; Seaburg, Adam G.

    2013-01-01

    Turbine-passed fish are exposed to rapid decreases in pressure which can cause barotrauma. The presence of an implanted telemetry tag increases the likelihood of injury or death from exposure to pressure changes, thus potentially biasing studies evaluating survival of turbine-passed fish. Therefore, a neutrally buoyant externally attached tag was developed to eliminate this bias in turbine passage studies. This new tag was designed not to add excess mass in water or take up space in the coelom, having an effective tag burden of zero with the goal of reducing pressure related biases to turbine survival studies. To determine if this new tag affects fish performance or susceptibility to predation, it was evaluated in the field relative to internally implanted acoustic transmitters (JSATS; Juvenile Salmon Acoustic Telemetry System) used widely for survival studies of juvenile salmonids. Survival and travel time through the study reach was compared between fish with either tag type in an area of high predation in the Snake and Columbia rivers, Washington. An additional group of fish affixed with neutrally-buoyant dummy external tags were implanted with passive integrated transponder (PIT) tags and recovered further downstream to assess external tag retention and injury. There were no significant differences in survival to the first detection site, 12 river kilometers (rkm) downstream of release. Travel times were also similar between groups. Conversely, externally-tagged fish had reduced survival (or elevated tag loss) to the second detection site, 65 rkm downstream. In addition, the retention study revealed that tag loss was first observed in fish recaptured approximately 9 days after release. Results suggest that this new tag may be viable for short term (<8 days) single-dam turbine-passage studies and under these situations, may alleviate the turbine passage-related bias encountered when using internal tags, however further research is needed to confirm this. PMID:24204947

  18. Physiological considerations in applying laboratory-determined buoyant densities to predictions of bacterial and protozoan transport in groundwater: Results of in-situ and laboratory tests

    USGS Publications Warehouse

    Harvey, R.W.; Metge, D.W.; Kinner, N.; Mayberry, N.

    1997-01-01

    Buoyant densities were determined for groundwater bacteria and microflagellates (protozoa) from a sandy aquifer (Cape Cod, MA) using two methods: (1) density-gradient centrifugation (DGC) and (2) Stoke's law approximations using sedimentation rates observed during natural-gradient injection and recovery tests. The dwarf (average cell size, 0.3 ??m), unattached bacteria inhabiting a pristine zone just beneath the water table and a majority (~80%) of the morphologically diverse community of free- living bacteria inhabiting a 5-km-long plume of organically-contaminated groundwater had DGC-determined buoyant densities <1.019 g/cm3 before culturing. In the aquifer, sinking rates for the uncultured 2-??m size class of contaminant plume bacteria were comparable to that of the bromide tracer (1.9 x 10-3 M), also suggesting a low buoyant density. Culturing groundwater bacteria resulted in larger (0.8-1.3 ??m), less neutrally- buoyant (1.043-1.081 g/cm3) cells with potential sedimentation rates up to 64-fold higher than those predicted for the uncultured populations. Although sedimentation generally could be neglected in predicting subsurface transport for the community of free-living groundwater bacteria, it appeared to be important for the cultured isolates, at least until they readapt to aquifer conditions. Culturing-induced alterations in size of the contaminant-plume microflagellates (2-3 ??m) were ameliorated by using a lower nutrient, acidic (pH 5) porous growth medium. Buoyant densities of the cultured microflagellates were low, i.e., 1.024-1.034 g/cm3 (using the DGC assay) and 1.017-1.039 g/cm3 (estimated from in-situ sedimentation rates), suggesting good potential for subsurface transport under favorable conditions.

  19. In-Situ Optical and Acoustical Measurements of the Buoyant Cyanobacterium P. Rubescens: Spatial and Temporal Distribution Patterns

    PubMed Central

    Hofmann, Hilmar; Peeters, Frank

    2013-01-01

    Optical (fluorescence) and acoustic in-situ techniques were tested in their ability to measure the spatial and temporal distribution of plankton in freshwater ecosystems with special emphasis on the harmful and buoyant cyanobacterium P. rubescens. Fluorescence was measured with the multi-spectral FluoroProbe (Moldaenke FluoroProbe, MFP) and a Seapoint Chlorophyll Fluorometer (SCF). In-situ measurements of the acoustic backscatter strength (ABS) were conducted with three different acoustic devices covering multiple acoustic frequencies (614 kHz ADCP, 2 MHz ADP, and 6 MHz ADV). The MFP provides a fast and reliable technique to measure fluorescence at different wavelengths in situ, which allows discriminating between P. rubescens and other phytoplankton species. All three acoustic devices are sensitive to P. rubescens even if other scatterers, e.g., zooplankton or suspended sediment, are present in the water column, because P. rubescens containing gas vesicles has a strong density difference and hence acoustic contrast to the ambient water and other scatterers. After calibration, the combination of optical and acoustical measurements not only allows qualitative and quantitative observation of P. rubescens, but also distinction between P. rubescens, other phytoplankton, and zooplankton. As the measuring devices can sample in situ at high rates they enable assessment of plankton distributions at high temporal (minutes) and spatial (decimeters) resolution or covering large temporal (seasonal) and spatial (basin scale) scales. PMID:24303028

  20. Rock uplift and exhumation of continental margins by the collision, accretion, and subduction of buoyant and topographically prominent oceanic crust

    NASA Astrophysics Data System (ADS)

    Spikings, Richard; Simpson, Guy

    2014-05-01

    Understanding the causes of rock and surface uplift is important because they control the location of mountain building, depocenters, and drainage characteristics and can influence climate. Here we combine previous thermochronological data with field observations to determine the amount of exhumation, rock, and surface uplift that occurs in the upper plate of Central and South American subduction zones during the collision, accretion, and subduction of oceanic plateaus and aseismic ridges. The collision of buoyant and topographically prominent oceanic plateaus and ridges can drive at least 5 km of rock uplift within 2 Ma. Uplift appears to be an immediate response to collision and is generally independent of the slab dip. The amount of rock uplift is controlled mainly by excess topography associated with the ridge (ultimately linked to buoyancy) and erosion, while it is also influenced by the strength of the subduction interface related to the presence of volcanic asperities and overpressured sediments in the subduction channel. The quantity of exhumation is strongly dependant on climate-induced erosion and the lifespan over which the topography is uplifted and supported. Sediment draining into the trench may leave the elevated ridge axis sediment starved, increasing the shear stresses at the ridge subduction interface, leading to positive feedback between ridge subduction, rock uplift, and exhumation. Trench-parallel variations in exhumation have a direct impact on exploration paradigms for porphyry-related metalliferous deposits, and it is likely that porphyry systems are completely eroded by the impingement of plateaus and aseismic ridges within temperate and tropical climates.

  1. Evolution of a buoyant outflow in the presence of complex topography: The Dardanelles plume (North Aegean Sea)

    NASA Astrophysics Data System (ADS)

    Androulidakis, Y. S.; Kourafalou, V. H.

    2011-04-01

    The outflow of Waters of Black Sea origin (BSW) through the Dardanelles Strait is the strongest buoyant input for the North Aegean Sea (NAS). Two opposing flows exist across the Dardanelles exit: a lighter, upper layer outflow (BSW) and a denser, deeper layer inflow (waters of Mediterranean origin). This study examines the processes influencing the plume development and evolution. The complex topography of the receiving basin (NAS) plays a significant role on the preferred BSW pathways that are controlled by the buoyancy and wind forcing. A high-resolution numerical model, the NAS-HYCOM (Hybrid Coordinate Ocean Model), is implemented to perform process-oriented experiments that examine the relative role of the forcing factors and topographic effects. Three major pathways are identified. In the absence of wind, an anticyclonic bulge is formed inducing a Westward Jet that is topographically guided between two islands near the outflow. Topography also controls the development of a buoyancy-driven Coastal Current and a Rim Current along the North Aegean shelf areas. Comparison of model results to analytical calculations suggests that topography modifies the formation and the ballooning of the anticyclonic bulge, which are controlled by the outflow rate, the resulting stratification and Coriolis. Experiments also employ several wind directions and magnitudes in combination with different outflow characteristics. The study elucidates the importance of the Aegean morphology on the processes controlling the coupling to the Black Sea. The BSW are found to influence both deep and shelf Aegean basins, along their overall cyclonic pathway toward the eastern Mediterranean.

  2. 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

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

    2010-01-01

    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

  3. Reactive multiphase flow at the pore-scale: the melting of a crystalline framework during the injection of buoyant hot volatiles

    NASA Astrophysics Data System (ADS)

    Andrea, P.; Huber, C.; Bachmann, O.; Chopard, B.

    2010-12-01

    Multiphase reactive flows occur naturally in various environments in the shallow subsurface, e.g. CO2 injections in saturated reservoirs, exsolved methane flux in shallow sediments and H20-CO2 volatiles in magmatic systems. Because of their multiphase nature together with the nonlinear feedbacks between reactions (dissolution/melting or precipitation) and the flow field at the pore-scale, the study of these dynamical processes remains a great challenge. In this study we focus on the injection of buoyant hot volatiles exsolved from a magmatic intrusion underplating a crystal-rich magma (porous medium). We use some simple theoretical models and a pore-scale multiphase reactive lattice Boltzmann model to investigate how the heat carried by the volatile phase affects the evolution of the porous medium spatially and temporally. We find that when the reaction rate is relatively slow and when the injection rate of volatiles is large (high injection Capillary number), the dissolution of the porous medium can be described by a local Peclet number (ratio of advective to diffusive flux of heat/reactant in the main gas channel). When the injection rate of volatile is reduced, or when the reaction rate is large, the dynamics transition to more complex regimes, where subvertical gas channels are no longer stable and can break into disconnected gas slugs. For the case of the injection of hot volatiles in crystal-rich magmatic systems, we find that the excess enthalpy advected by buoyant volatiles penetrates the porous medium over distances ~r Pe, where r is the average radius of the volatile channel (~pore size). The transport of heat by buoyant gases through a crystal mush is therefore in most cases limited to distances < meters. Our results also suggest that buoyant volatiles can carry chemical species (Li,F, Cl) far into a mush as their corresponding local Peclet number is several orders of magnitude greater than that for heat, owing to their low diffusion coefficients.

  4. Quantitative Effect of Variable Entrainment on the Hydrothermal Heat Outputs Deduced From the Heights Reached by Submarine Buoyant Plumes

    NASA Astrophysics Data System (ADS)

    Kaminski, E.; Carazzo, G.; Tait, S.

    2007-12-01

    In the absence of direct measurements of the heat flux released by hydrothermal vent activity, the large submarine plumes associated provide a key information to estimate thermal outputs. Physical models of turbulent plumes have shown that the maximum height reached by a plume in a stratified environment can be related only to its source buoyancy flux, the stratification of the surrounding fluid and the efficiency of the mixing between both fluids. If one assumes that the mixing is constant along the distance from the source and if the ambient stratification is known, the maximum height reached by the plume provides directly the source heat flux. These models have been adapted to predict the rise of buoyant hydrothermal plumes as a function of the source heat flux in the ambient seawater of the Atlantic and the Pacific Oceans. Five plumes heights detected above the TAG vent field in the Mid-Atlantic Ridge (26° N) have been used to calculate the heat and vent fluxes emitted from this hydrothermal system. We will show that these estimations are erroneous by a factor 3 because of the simple assumption that the mixing is constant with depth. We present a new model of turbulent entrainment highlighting the fundamental effect of the plume buoyancy on the mixing. The stratification of the ambient seawater induces a negative buoyancy close to the maximum height which can considerably reduce the turbulent entrainment. We re- evaluate the thermal ouput of the TAG hydrothermal field to 2850 MW. This generic approach can be applied to any submarine hydrothermal system for which the density stratification in the ambient seawater is known.

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

    NASA Astrophysics Data System (ADS)

    Black, Kerry P.

    1993-03-01

    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.

  6. COMMERCIAL OPPORTUNITY: Neutrally Buoyant

    E-print Network

    Matthews, Adrian

    of the ocean, the start of a complex range of interactions and exchanges which constitute the marine food web of the material sinks into the deeper water to feed the biological communities in the dark ocean. This process

  7. JBFA - buoyant flight

    NASA Technical Reports Server (NTRS)

    Ohari, T.

    1982-01-01

    A method was developed whereby a balloon was used to carry lumber out of a forest in order to continue lumber production without destroying the natural environment and view of the forest. Emphasis was on the best shape for a logging balloon, development of a balloon logging system suitable for cutting lumber and safety plans, tests on balloon construction and development of netting, and weather of mountainous areas, especially solutions to problems caused by winds.

  8. Buoyant despite Downturn

    ERIC Educational Resources Information Center

    Berry, John N., III; Fialkoff, Francine; Fox, Bette-Lee; Hadro, Josh; Horrocks, Norman; Kuzyk, Raya; Oder, Norman

    2009-01-01

    Even as libraries face the economic downturn, a record-setting number of people attended the American Library Association (ALA) annual conference in Chicago, July 9-15. The tough economy, however, was felt in the number of exhibitors, which declined from the previous record set in 2007 in Washington, DC, and in anecdotal evidence that suggested…

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

    NASA Astrophysics Data System (ADS)

    Gomm, Leslie Sharon

    1999-10-01

    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.

  10. Some factors affecting the use of lighter than air systems. [economic and performance estimates for dirigibles and semi-buoyant hybrid vehicles

    NASA Technical Reports Server (NTRS)

    Havill, C. D.

    1974-01-01

    The uses of lighter-than-air vehicles are examined in the present day transportation environment. Conventional dirigibles were found to indicate an undesirable economic risk due to their low speeds and to uncertainties concerning their operational use. Semi-buoyant hybrid vehicles are suggested as an alternative which does not have many of the inferior characteristics of conventional dirigibles. Economic and performance estimates for hybrid vehicles indicate that they are competitive with other transportation systems in many applications, and unique in their ability to perform some highly desirable emergency missions.

  11. 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)

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

    2010-12-01

    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.

  12. The potential for buoyant displacement gas release events in Tank 241-SY-102 after waste transfer from Tank 241-SY-101

    SciTech Connect

    BE Wells; PE Meyer; G Chen

    2000-05-10

    Tank 241-SY-101 (SY-101) is a double-shell, radioactive waste storage tank with waste that, before the recent transfer and water back-dilution operations, was capable of retaining gas and producing buoyant displacement (BD) gas release events (GREs). Some BD GREs caused gas concentrations in the tank headspace to exceed the lower flammability limit (LFL). A BD GRE occurs when a portion of the nonconvective layer retains enough gas to become buoyant, rises to the waste surface, breaks up, and releases some of its stored gas. The installation of a mixer pump in 1993 successfully mitigated gas retention in the settled solids layer in SY-101 and has since prevented BD GREs. However, operation of the mixer pump over the years caused gas retention in the floating crust layer and a corresponding accelerated waste level growth. The accelerating crust growth trend observed in 1997--98 led to initiation of sequences of waste removal and water back-dilutions in December 1999. Waste is removed from the mixed slurry layer in Tank SY-101 and transferred into Tank 241-Sy-102 (SY-102). Water is then added back to dissolve soluble solids that retain gas. The initial transfer of 89,500 gallons of SY-101 waste, diluted in-line at 0.94:1 by volume with water, to SY-102 was conducted in December 1999. The second transfer of 230,000 gallons of original SY-101 waste, diluted approximately 0.9:1, was completed in January 2000, and the third transfer of 205,500 gallons of original SY-101 waste diluted at 0.9:1 was completed in March 2000.

  13. Horizontal evolution of tidally modulated buoyant plumes and the subsequent genesis of non linear internal waves as observed with an AUV based microstructure profiler.

    NASA Astrophysics Data System (ADS)

    toberman, matthew; Inall, Mark; Boyd, Tim

    2013-04-01

    The tidally modulated outflow of brackish water from a sea loch forms a thin stable surface layer that propagates into the coastal ocean as a buoyant gravity current, transporting nutrients and sediments, as well as fresh water, heat and momentum. The fresh intrusion propagates as an undular bore, and the introduced stratification supports trains of non-linear internal waves (NLIWs). In February 2011 an Autonomous Underwater Vehicle (AUV) was used on repeated reciprocal transects to make simultaneous CTD, ADCP and shear microstructure measurements of the evolution of these phenomena in conjunction with conventional mooring measurements. AUV-based temperature and salinity signals of NLIWs of depression were observed together with increased turbulent kinetic energy dissipation rates of over two orders of magnitude within and in the wake of the NLIWs. Repeated measurements over several tidal cycles allow a unique opportunity to investigate the horizontal structure of these phenomena, the interaction of each tidally driven pulse with ambient stratification and the remnants of previous plumes, as well as the genesis of and subsequent mixing induced by the NLIWs.

  14. Properties of viruses of the potyvirus group. 2. Buoyant density, S value, particle morphology, and molecular weight of the coat protein subunit of bean yellow mosaic virus, pea mosaic virus, lettuce mosaic virus, and potato virus Y N

    Microsoft Academic Search

    H. Huttinga; W. H. M. Mosch

    1974-01-01

    The buoyant densities of bean yellow mosaic virus (BYMV) B25, pea mosaic virus (PMV) E198, lettuce mosaic virus (LMV), and potato virus YN (PVYN) were 1.318, 1.321, 1.330, and 1.326 g\\/ml, respectively. Their S values were 143, 140, 143, and 145 S. The particle morphology of BYMV B25, PMV E198, and LMV could reversibly be changed by magnesium ions. PVYN

  15. Petrochronological and structural arguments for upper plate thickening and relamination of the lower plate buoyant material in the Variscan Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Pe?estý, Vít; Holder, Robert; Lexa, Ondrej; Racek, Martin; Je?ábek, Petr

    2014-05-01

    Recent tectonic models for the Variscan evolution of the Bohemian Massif emphasize the role of Rayleigh-Taylor instability for the 355-340 Ma evolution of the Moldanubian domain. This model is based on the presence of weak, low-density felsic material tectonically underplating a high-density mafic layer and its subsequent gravity-driven overturn. However, earlier phases of the Variscan orogeny concerning the emplacement of felsic low-density material to the base of the upper plate are so far poorly documented. We contribute to this problem by deciphering of polyphase early-Variscan (~375 Ma) deformation and metamorphism close to the main Variscan suture. Detailed structural, pseudosection and microstructural analyses combined with LASS monazite dating were carried out in metapelites along the western margin of the upper plate represented by the Teplá Crystalline Complex (TCC). This region is represented by a ~25 km wide deformation zone with E-W metamorphic gradients associated with two distinct early-Variscan events (~380-375 and ~375-370 Ma). The first compressional event produced a vertical NNE-SSW trending fabric and a continuous and prograde Barrovian metamorphic sequence ranging from biotite to kyanite zones at a field geotherm of 20 to 25 °C/km. Subsequently, a gently SE dipping normal shear-zone associated with retrogression develops along the base of the TCC. This sub-horizontal fabric shows normal metamorphic zonation ranging from sillimanite, biotite to chlorite zones and indicates vertical shortening related to unroofing of high pressure metabasites of the underlying Mariánské-Lázn? Complex. The first metamorphic fabric is interpreted to result from early thickening of the upper plate during continental underthrusting of Saxothuringian continent (380 to 375 Ma) while the second deformation and metamorphism (~370 Ma) reflects vertical shortening produced by buoyant uplift of accreted Saxothuringian felsic crust. This event is the unique yet indirect testimony of relamination mechanisms governing further evolution of the orogenic lower crust in the Bohemian massif.

  16. A new time series of particle export from neutrally buoyant sediments traps at the Bermuda Atlantic Time-series Study site

    NASA Astrophysics Data System (ADS)

    S. A., Owens; K. O., Buesseler; C. H., Lamborg; Valdes, J.; M. W., Lomas; R. J., Johnson; D. K., Steinberg; D. A, Siegel

    2013-02-01

    Neutrally buoyant sediment traps (NBSTs) were deployed concurrently with particle interceptor traps (PITs) on monthly cruises of the Bermuda Atlantic Time-series Study (BATS) from June 2007 to July 2010. In most months, particulate organic carbon flux measured by the two sediment trap systems agreed within the range of variability for two separate NBSTs. In three periods of this study however, the PITs collected more than three times the amount of particulate organic carbon (POC) than the NBSTs. One of these periods coincided with two instances when the mixed layer was deeper than the trap deployment depth, which may lead to biased collection. One of the anomalous periods occurred during summer months, for which we were unable to find existing evidence of biogeochemical changes that would lead to such increases in POC flux. The third anomalous period occurred when the POC flux measured by the NBSTs was near zero. We hypothesize that the PITs may have a positive bias at low fluxes relative to the NBSTs. Zooplankton swimmers accounted for 49±20% of the total measured carbon flux over the three year period and swimmer removal by screening of samples through a 350 ?m mesh was established as an effective method for this site. Process blank corrections based on sample-identical blanks were important for determining mass and carbon flux from both the NBSTs and the PITs. This new record of particle export from NBSTs suggests that the observed carbon imbalance in this region of the ocean (Michaels et al., 1994) is not due to undersampling by the PITs and that export ratios may be even lower than previously thought.

  17. Hamiltonian structure for a neutrally buoyant rigid body interacting with N vortex rings of arbitrary shape: the case of arbitrary smooth body shape

    NASA Astrophysics Data System (ADS)

    Shashikanth, Banavara N.; Sheshmani, Artan; Kelly, Scott David; Marsden, Jerrold E.

    2008-01-01

    We present a (noncanonical) Hamiltonian model for the interaction of a neutrally buoyant, arbitrarily shaped smooth rigid body with N thin closed vortex filaments of arbitrary shape in an infinite ideal fluid in Euclidean three-space. The rings are modeled without cores and, as geometrical objects, viewed as N smooth closed curves in space. The velocity field associated with each ring in the absence of the body is given by the Biot-Savart law with the infinite self-induced velocity assumed to be regularized in some appropriate way. In the presence of the moving rigid body, the velocity field of each ring is modified by the addition of potential fields associated with the image vorticity and with the irrotational flow induced by the motion of the body. The equations of motion for this dynamically coupled body-rings model are obtained using conservation of linear and angular momenta. These equations are shown to possess a Hamiltonian structure when written on an appropriately defined Poisson product manifold equipped with a Poisson bracket which is the sum of the Lie-Poisson bracket from rigid body mechanics and the canonical bracket on the phase space of the vortex filaments. The Hamiltonian function is the total kinetic energy of the system with the self-induced kinetic energy regularized. The Hamiltonian structure is independent of the shape of the body, (and hence) the explicit form of the image field, and the method of regularization, provided the self-induced velocity and kinetic energy are regularized in way that satisfies certain reasonable consistency conditions.

  18. ANALYSIS OF BUOYANT SURFACE JETS

    EPA Science Inventory

    To obtain improved prediction of heated plume characteristics from a surface jet, an integral analysis computer model was modified and a comprehensive set of field and laboratory data available from the literature was gathered, analyzed, and correlated for estimating the magnitud...

  19. Buoyant melting instabilities beneath extending lithosphere

    E-print Network

    Tackley, Paul J.

    . Introduction [2] Upwelling fertile mantle beneath extending litho- sphere may undergo decompression partial melting, and is the typical source of volcanism in most extensional prov- inces on Earth. Decompression unstable behavior. This phenomenon has also been termed a ``decompression melting instability'' by Raddick

  20. Generalized ballistic deposition of small buoyant particles

    NASA Astrophysics Data System (ADS)

    Csúcs, G.; Ramsden, J. J.

    1998-07-01

    The adsorption kinetics of the protein bee venom phospholipase A2 to a smooth, planar metal oxide surface has been measured under controlled hydrodynamic conditions using optical waveguide lightmode spectroscopy (OWLS). Adsorption follows the generalized ballistic deposition (GBD) model, except at low bulk protein concentrations, where Langmuir kinetics are observed.

  1. Buoyant currents arrested by convective dissolution

    E-print Network

    MacMinn, Christopher W.

    When carbon dioxide (CO[subscript 2]) dissolves into water, the density of water increases. This seemingly insubstantial phenomenon has profound implications for geologic carbon sequestration. Here we show, by means of ...

  2. Neutrally Buoyant Elliptical Cylinders in Simple Shear

    Microsoft Academic Search

    Claudia Zettner; Minami Yoda

    2000-01-01

    An elliptical cylinder in simple shear is a 2D Lagrangian model of a particle in a dilute sheared suspension. Recent simulations(E. J. Ding and C. K. Aidun ``The dynamics and scaling law for particles suspended in shear flow with inertia'' To appear in J. Fluid Mech.) (2000) have shown that bodies with aspect ratio AR < 1 exhibit two behaviors

  3. JBFA-Buoyant Flight, Special Edition

    NASA Technical Reports Server (NTRS)

    Wada, C.; Terada, K.; Ishii, C.; Nagamatsu, K.; Makino, M.; Ichiyoshi, S.

    1982-01-01

    Progress in the project to traverse the Pacific Ocean by manned balloon is summarized. The development of a hybrid lighter than aircraft combining the buoyancy of a gas bag with the vertical lift off capabilities of the helicopter is also addressed.

  4. Experimental investigation of a stratified buoyant wake

    E-print Network

    Kraft, Wayne Neal

    2004-11-15

    of the Rayleigh-Taylor mixing layer. The development of the near wake in the presence of unstable stratification is examined, in addition to the recovery of the buoyancy driven mixing layer. Planar laser induced fluorescence (PLIF) is used to visualize the mixing...

  5. A modeling of buoyant gas plume migration

    SciTech Connect

    Silin, D.; Patzek, T.; Benson, S.M.

    2008-12-01

    This work is motivated by the growing interest in injecting carbon dioxide into deep geological formations as a means of avoiding its atmospheric emissions and consequent global warming. Ideally, the injected greenhouse gas stays in the injection zone for a geologic time, eventually dissolves in the formation brine and remains trapped by mineralization. However, one of the potential problems associated with the geologic method of sequestration is that naturally present or inadvertently created conduits in the cap rock may result in a gas leakage from primary storage. Even in a supercritical state, the carbon dioxide viscosity and density are lower than those of the formation brine. Buoyancy tends to drive the leaked CO{sub 2} plume upward. Theoretical and experimental studies of buoyancy-driven supercritical CO{sub 2} flow, including estimation of time scales associated with plume evolution and migration, are critical for developing technology, monitoring policy, and regulations for safe carbon dioxide geologic sequestration. In this study, we obtain simple estimates of vertical plume propagation velocity taking into account the density and viscosity contrast between CO{sub 2} and brine. We describe buoyancy-driven countercurrent flow of two immiscible phases by a Buckley-Leverett type model. The model predicts that a plume of supercritical carbon dioxide in a homogeneous water-saturated porous medium does not migrate upward like a bubble in bulk water. Rather, it spreads upward until it reaches a seal or until it becomes immobile. A simple formula requiring no complex numerical calculations describes the velocity of plume propagation. This solution is a simplification of a more comprehensive theory of countercurrent plume migration (Silin et al., 2007). In a layered reservoir, the simplified solution predicts a slower plume front propagation relative to a homogeneous formation with the same harmonic mean permeability. In contrast, the model yields much higher plume propagation estimates in a high-permeability conduit like a vertical fracture.

  6. Candle Flames in Non-Buoyant Atmospheres

    NASA Technical Reports Server (NTRS)

    Dietrich, D. L.; Ross, H. D.; Shu, Y.; Tien, J. S.

    1999-01-01

    This paper addresses the behavior of a candle flame in a long-duration, quiescent microgravity environment both on the space Shuttle and the Mir Orbiting Station (OS). On the Shuttle, the flames became dim blue after an initial transient where there was significant yellow (presumably soot) in the flame. The flame lifetimes were typically less than 60 seconds. The safety-mandated candlebox that contained the candle flame inhibited oxygen transport to the flame and thus limited the flame lifetime. 'Me flames on the Mir OS were similar, except that the yellow luminosity persisted longer into the flame lifetime because of a higher initial oxygen concentration. The Mir flames burned for as long as 45 minutes. The difference in the flame lifetime between the Shuttle and Mir flames was primarily the redesigned candlebox that did not inhibit oxygen transport to the flame. In both environments, the flame intensity and the height-to-width ratio gradually decreased as the ambient oxygen content in the sealed chamber slowly decreased. Both sets of experiments showed spontaneous, axisymmetric flame oscillations just prior to extinction. The paper also presents a numerical model of candle flame. The model is detailed in the gas-phase, but uses a simplified liquid/wick phase. 'Me model predicts a steady flame with a shape and size quantitatively similar to the Shuttle and Mir flames. ne model also predicts pre-extinction flame oscillations if the decrease in ambient oxygen is small enough.

  7. Candle Flames in Non-Buoyant Atmospheres

    NASA Technical Reports Server (NTRS)

    Dietrich, D. L.; Ross, H. D.; Shu, Y.; Chang, P.; Tien, J. S.

    2000-01-01

    This paper addresses the behavior of a candle flame in a long-duration, quiescent microgravity environment both on the space Shuttle and the Mir Orbiting Station. On the Shuttle, the flames became dim blue after an initial transient where there was significant yellow (presumably soot) in the flame. The flame lifetimes were typically less than 60 seconds. The safety-mandated candlebox that contained the candle flame inhibited oxygen transport to the flame and thus limited the flame lifetime. The flames on the Mir were similar, except that the yellow luminosity persisted longer into the flame lifetime because of a higher initial oxygen concentration, The Mir flames burned for as long as 45 minutes. The difference in the flame lifetime between the Shuttle and Mir flames was primarily the redesigned candlebox that did not inhibit oxygen transport to the flame. In both environments, the flame intensity and the height-to-width ratio gradually decreased as the ambient oxygen content in the sealed chamber slowly decreased. Both sets of experiments showed spontaneous, axisymmetric flame oscillations just prior to extinction. The paper also presents a numerical model of a candle flame. The formulation is two-dimensional and time-dependent in the gas phase with constant specific heats, thermal conductivity and Lewis number (although different species can have different Lewis numbers), one-step finite-rate kinetics, and gas-phase radiative losses from CO2 and H2O. The treatment of the liquid/wick phase assumes that the, fuel evaporates from a constant diameter sphere connected to an inert cone. The model predicts a steady flame with a shape and size quantitatively similar to the Shuttle and Mir flames. The computation predicts that the flame size will increase slightly with increasing ambient oxygen mole fraction. The model also predicts pre-extinction flame oscillations if the rate of decrease in ambient oxygen is small enough, such as that which would occur for a flame burning in a sealed ambient.

  8. Candle Flames in Non-Buoyant Atmospheres

    Microsoft Academic Search

    D. L. DIETRICH; H. D. ROSS; Y. SHU; P. CHANG; J. S. TIEN

    2000-01-01

    This paper addresses the behavior of a candle flame in a long-duration, quiescent microgravity environment both on the space Shuttle and the Mir Orbiting Station. On the Shuttle, the flames became dim blue after an initial transient where there was significant yellow (presumably soot) in the flame. The flame lifetimes were typically less than 60 seconds. The safety-mandated candlebox that

  9. TURBULENCE MODELING APPLIED TO BUOYANT PLUMES

    EPA Science Inventory

    A viable computer model was developed that is based on second-order closure of the turbulent correlation equations for predicting the fate of nonchemically reacting contaminants released in the atmospheric boundary layer. The invariant turbulence model discussed in previous repor...

  10. Buoyant Rover for Under-Ice Exploration

    NASA Astrophysics Data System (ADS)

    Berisford, D. F.; Leichty, J. M.; Klesh, A. T.; Matthews, J. B.; Hand, K. P.

    2012-12-01

    We have designed, constructed and tested a prototype robotic mobility platform for exploring the underside of ice sheets in frozen lake or ocean environments. The ice-water interface often provides some of the most interesting and dynamic chemistry in partially frozen systems, as dissolved impurities are rejected from the advancing freezing front. Higher concentrations of microorganisms can be found in this region, and the topography of the ice underside can help reveal the history of its formation. Furthermore, in lake environments ice cover can serve to trap gases released from biological and geological processes in the subsurface. The rover uses a two-wheeled design with a flexible dragging tail, enabling it to fit into a 10-inch diameter ice borehole. The sealed air-filled cylindrical body, along with closed-cell foam inside of cone-shaped wheels, provides buoyancy force to enable roving along the underside of the ice. The prototype contains two cameras that stream live video via a tethered connection to a ground station and uses semi-autonomous control via a PC. Preliminary testing of the prototype in a cold lab and in northern Alaskan thermokarst lakes demonstrates the utility and simplicity of this type of robotic platform for exploring the ice-water interface. This technology has potential future use in landed missions to icy ocean worlds in the solar system.

  11. 75 FR 36134 - Self-Regulatory Organizations; International Securities Exchange, LLC; Notice of Filing and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-24

    ...International Group, Inc. (``AIG''), American Express Company (``AXP''), Best Buy Company (``BBY''), Caterpillar, Inc. (``CAT''), Chesapeake Energy Corporation (``CHK''), Dendreon Corporation (``DNDN''),...

  12. Modeling of the reactive negatively buoyant titanium tetrachloride

    SciTech Connect

    Khajehnajafi, S. [DuPont-SAFER Systems, Inc., Westlake Village, CA (United States)

    1995-12-31

    Modeling the dispersion of the chemically reacting materials is challenging and is of interest to many plant sites. The formation of the consortium of the big oil companies to tackle complex nature of hydrogen fluoride dispersion, the study of the nitrogen tetroxide by the US army, shows the necessities of such models. In this paper the authors present the modeling of the reacting chemical titanium tetrachloride (TiCl{sub 4}) and the dispersion of vapor cloud formed. This substance is heavier than air and reacts with the ambient moisture to produce lighter materials. The reaction is very fast, exothermic, and yields corrosive hydrogen chloride vapor and harmful solid particles of titanium dioxide. The concern besides the health effects from these reactants is the reduction of the visibility due to the white solid particles which makes the escaping from the scene of the accident very difficult.

  13. 46 CFR 160.010-3 - Inflatable buoyant apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...not less than 200 mm (8 in.). (16) Cold-inflation test. The cold-inflation test required under paragraph 1...NON-SOLAS REVERSIBLE”, and the equipment pack must be identified as an “HSC Pack”. [CGD 85-205, 62 FR 25545,...

  14. Second order closure modeling of turbulent buoyant wall plumes

    NASA Technical Reports Server (NTRS)

    Zhu, Gang; Lai, Ming-Chia; Shih, Tsan-Hsing

    1992-01-01

    Non-intrusive measurements of scalar and momentum transport in turbulent wall plumes, using a combined technique of laser Doppler anemometry and laser-induced fluorescence, has shown some interesting features not present in the free jet or plumes. First, buoyancy-generation of turbulence is shown to be important throughout the flow field. Combined with low-Reynolds-number turbulence and near-wall effect, this may raise the anisotropic turbulence structure beyond the prediction of eddy-viscosity models. Second, the transverse scalar fluxes do not correspond only to the mean scalar gradients, as would be expected from gradient-diffusion modeling. Third, higher-order velocity-scalar correlations which describe turbulent transport phenomena could not be predicted using simple turbulence models. A second-order closure simulation of turbulent adiabatic wall plumes, taking into account the recent progress in scalar transport, near-wall effect and buoyancy, is reported in the current study to compare with the non-intrusive measurements. In spite of the small velocity scale of the wall plumes, the results showed that low-Reynolds-number correction is not critically important to predict the adiabatic cases tested and cannot be applied beyond the maximum velocity location. The mean and turbulent velocity profiles are very closely predicted by the second-order closure models. but the scalar field is less satisfactory, with the scalar fluctuation level underpredicted. Strong intermittency of the low-Reynolds-number flow field is suspected of these discrepancies. The trends in second- and third-order velocity-scalar correlations, which describe turbulent transport phenomena, are also predicted in general, with the cross-streamwise correlations better than the streamwise one. Buoyancy terms modeling the pressure-correlation are shown to improve the prediction slightly. The effects of equilibrium time-scale ratio and boundary condition are also discussed.

  15. Lipid composition of positively buoyant eggs of reef building corals

    NASA Astrophysics Data System (ADS)

    Arai, Iakayuki; Kato, Misako; Heyward, Andrew; Ikeda, Yutaka; Iizuka, Tokio; Maruyama, Tadashi

    1993-07-01

    Lipid composition of the eggs of three reef building corals, Acropora millepora, A. tenuis and Montipora digitata, were determined. Sixty to 70% of the egg dry weight was lipid, which consisted of wax esters (69.5 81.8%), triacylglycerols (1.1 8.4%) and polar lipids c/mainly phospholipids (11.9 13.2%). Montipora digitata also contained some polar lipids typical of the thylakoid membrane in chloroplasts, probably due to the presence of symbiotic zooxanthellae in the eggs. The wax esters appeared to be the major contributor to positive buoyancy of the eggs, and specific gravity of wax esters in A. millepora was estimated to be 0.92. Among the fatty acids of the wax esters, 34.9 51.3% was hexadecanoic acid (16:0) while the major fatty acids in polar lipids were octadecenoic acid (18:1), hexadecanoic acid (16:0), eicosapentaenoic acid (20:5) and eicosatetraenoic acid (20:4). The wax ester appears to be the main component of the 4.5 6.0 ?m diameter lipid droplets which fill most of the central mass of the coral eggs.

  16. Civil markets for buoyant heavy-lift vehicles

    NASA Technical Reports Server (NTRS)

    Mettam, P. J.; Hansen, D.; Ardema, M. D.

    1981-01-01

    Worldwide civil markets for heavy lift airships were investigated. Substantial potential market demand was identified for payloads of from 13 to 800 tons. The largest markets appear to be in applications to relieve port congestion, construction of power generating plants, and, most notably, logging. Because of significant uncertainties both in vehicle and market characteristics, further analysis will be necessary to verify the identified market potential of heavy lift airship concepts.

  17. Flow-induced reconfiguration of buoyant and flexible aquatic vegetation

    E-print Network

    Nepf, Heidi

    Plant posture can play a key role in the health of aquatic vegetation, by setting drag, controlling light availability, and mediating the exchange of nutrients and oxygen. We study the flow-induced reconfiguration of ...

  18. Bottom tension fence-type water buoyant containment boom

    SciTech Connect

    Brown, L. S.; March, F. A.

    1981-06-02

    A flexible, fence-type, water-borne pollutant containment boom is disclosed having a flexible, permanently attached tension reinforcing belt of continuous, substantially parallel, high modulus, aramid fibers adhesively secured to the boom proximate its bottom edge and having a plurality of handles spaced along the top edge of the boom, the handles being molded on both sides of the boom and overlapping the top edge and surrounding openings cut in the boom proximate the top edge leaving flaps of boom material to selectively close the openings.

  19. Time-dependent buoyant puff model for explosive sources

    SciTech Connect

    Kansa, E.J.

    1997-01-01

    Several models exist to predict the time dependent behavior of bouyant puffs that result from explosions. This paper presents a new model that is derived from the strong conservative form of the conservation partial differential equations that are integrated over space to yield a coupled system of time dependent nonlinear ordinary differential equations. This model permits the cloud to evolve from an intial spherical shape not an ellipsoidal shape. It ignores the Boussinesq approximation, and treats the turbulence that is generated by the puff itself and the ambient atmospheric tubulence as separate mechanisms in determining the puff history. The puff cloud rise history was found to depend no only on the mass and initial temperature of the explosion, but also upon the stability conditions of the ambient atmosphere. This model was calibrated by comparison with the Roller Coaster experiments.

  20. Time-dependent buoyant puff model for explosive sources

    SciTech Connect

    Kansa, E.J.

    1997-10-01

    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%.

  1. Robust Outflow Boundary Conditions for Strongly Buoyant Turbulent Jet Flames

    Microsoft Academic Search

    Christian Walchshofer; Helfried Steiner; Günter Brenn

    2011-01-01

    The issue of prescribing open boundary conditions appropriate for highly transient flow simulations is a non-trivial one.\\u000a It may have significant impact on the stability of the computations and the quality of the numerical results. The present\\u000a paper proposes an outflow boundary condition which ensures stable simulations without significant losses in accuracy for use\\u000a in direct numerical simulations of strongly

  2. Countering Solutal Buoyant Convection with High Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Ramachandran, N.; Leslie, F. W.

    2002-01-01

    An important component in biotechnology, particularly in the area of protein engineering and rational drug design is the knowledge of the precise three-dimensional molecular structure of proteins. The quality of structural information obtained from X-ray diffraction methods is directly dependent on the degree of perfection of the protein crystals. As a consequence, the growth of high quality macromolecular crystals for diffraction analyses has been the central focus for biochemist, biologists, and bioengineers. Macromolecular crystals are obtained from solutions that contain the crystallizing species in equilibrium with higher aggregates, ions, precipitant, other possible phases of the protein, foreign particles, the walls of the container, and a likely host of other impurities. By changing transport modes in general, i.e., reduction of convection and sedimentation, as is achieved in microgravity, we have been able to dramatically effect the movement and distribution of macromolecules in the fluid, and thus their transport, formation of crystal nuclei, and adsorption to the crystal surface. While a limited number of high quality crystals from space flights have been obtained, as the recent National Research Council (NRC) review of the NASA microgravity crystallization program pointed out, the scientific approach and research in crystallization of proteins has been mainly empirical yielding inconclusive results. We postulate that we can reduce convection in ground-based experiments and we can understand the different aspects of convection control through the use of strong magnetic fields and field gradients. We postulate that limited convection in a magnetic field will provide the environment for the growth of high quality crystals. The approach exploits the variation of fluid magnetic susceptibility with concentration for this purpose and the convective damping is realized by appropriately positioning the crystal growth cell so that the magnetic susceptibility force counteracts terrestrial gravity. The general objective is to test the hypothesis of convective control using a strong magnetic field and magnetic field gradient and to understand the nature of the various forces that come into play. Specifically we aim to delineate causative factors and to quantify them through experiments, analysis and numerical modeling. The paper will report on the current status of the investigation and discuss results from the experimental and modeling efforts.

  3. Continents as lithological icebergs: The importance of buoyant lithospheric roots

    USGS Publications Warehouse

    Abbott, D.H.; Drury, R.; Mooney, W.D.

    1997-01-01

    An understanding of the formation of new continental crust provides an important guide to locating the oldest terrestrial rocks and minerals. We evaluated the crustal thicknesses of the thinnest stable continental crust and of an unsubductable oceanic plateau and used the resulting data to estimate the amount of mantle melting which produces permanent continental crust. The lithospheric mantle is sufficiently depleted to produce permanent buoyancy (i.e., the crust is unsubductable) at crustal thicknesses greater than 25-27 km. These unsubductable oceanic plateaus and hotspot island chains are important sources of new continental crust. The newest continental crust (e.g., the Ontong Java plateau) has a basaltic composition, not a granitic one. The observed structure and geochemistry of continents are the result of convergent margin magmatism and metamorphism which modify the nascent basaltic crust into a lowermost basaltic layer overlain by a more silicic upper crust. The definition of a continent should imply only that the lithosphere is unsubductable over ??? 0.25 Ga time periods. Therefore, the search for the oldest crustal rocks should include rocks from lower to mid-crustal levels.

  4. 46 CFR 160.010-3 - Inflatable buoyant apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...with the floor arranged between the buoyancy chambers so that the apparatus can...back onto the floor. (8) If the buoyancy tubes are not vivid reddish orange...panels of such hue must be secured to the buoyancy chambers so that a minimum of 1 m2...

  5. 46 CFR 160.010-3 - Inflatable buoyant apparatus.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...with the floor arranged between the buoyancy chambers so that the apparatus can...back onto the floor. (8) If the buoyancy tubes are not vivid reddish orange...panels of such hue must be secured to the buoyancy chambers so that a minimum of 1 m2...

  6. 46 CFR 160.010-3 - Inflatable buoyant apparatus.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...with the floor arranged between the buoyancy chambers so that the apparatus can...back onto the floor. (8) If the buoyancy tubes are not vivid reddish orange...panels of such hue must be secured to the buoyancy chambers so that a minimum of 1 m2...

  7. 46 CFR 160.010-3 - Inflatable buoyant apparatus.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...with the floor arranged between the buoyancy chambers so that the apparatus can...back onto the floor. (8) If the buoyancy tubes are not vivid reddish orange...panels of such hue must be secured to the buoyancy chambers so that a minimum of 1 m2...

  8. Label-free buoyant mass assays with suspended microchannel resonators

    E-print Network

    Von Muhlen, Marcio Goldani

    2010-01-01

    Improved methods are needed for routine, inexpensive monitoring of biomarkers that could facilitate earlier detection and characterization of complex diseases like cancer. Development of new assay formats based on microfluidic, ...

  9. Comparison of fish catches with buoyant pop nets and seines in vegetated and nonvegetated habitats

    USGS Publications Warehouse

    Dewey, M.R.; Holland-Bartels, L. E.; Zigler, S.J.

    1989-01-01

    Two models of pop nets were developed to sample fish in shallow riverine waters, one for use in vegetated areas and the other for nonvegetated areas. Both nets have a mechanical release mechanism that can be tripped from the water surface. Replicated field tests were conducted to compare pop-net catches with bag-seine collections every 2 weeks from May through mid-October. Overall, total catch per effort did not vary significantly (P 2) was smaller than the area swept by the average seine haul (70-140 m2). The pop net effectively sampled fish in shallow nonvegetated habitats and was useful in heavily vegetated areas where seining or electroshocking was difficult.

  10. Pore-Scale Modeling of Reactive-Multiphase-Buoyant Flow for Carbon Capture and Storage

    NASA Astrophysics Data System (ADS)

    Anwar, S.; Cunningham, J. A.; Trotz, M.; Thomas, M. W.; Stewart, M.

    2010-12-01

    Physical and geochemical processes at multiple scales are yet to be understood for the storage of carbon dioxide (CO2) in aquifers and the concomitant mitigation of CO2 concentration in the atmosphere. In deep saline aquifers, the pores in the potential aquifers for CO2 storage are initially filled with saline water (brine). The entrapment of brine in pores after injection of CO2 is controlled by capillary forces and by the inertial force driving CO2 inside the carbonate aquifer. The entrapped/residual brine will be a site for geochemical reactions which could alter the pore network and/or the permeability of the formation. Therefore, the pore-scale understanding of displacement of resident brine by CO2 is critical to evaluate the storage efficiency of carbonate aquifers and to quantify any dissolution or precipitation of minerals (e.g., gypsum, calcite, dolomite). In this project, we have developed a multiphase flow model, based on the lattice Boltzmann equation, that can describe pore-scale displacement of brine by invading CO2. The multiphase flow model is applied to three different pore networks saturated with brine. The amount of brine trapped after invasion of the domain by CO2 is strongly dependent on the pore network. We also examine the effects of CO2 density and viscosity (which depend on formation temperature and pressure) on the amount of entrapped brine. Only by resolving the flow at the pore scale can we predict the residual brine saturation and other parameters which control CO2 sequestration in deep saline aquifers. Future work will focus on coupling the pore-scale multiphase flow model to a chemistry model to predict mineral dissolution and precipitation.

  11. Buoyant replenishment in silicic magma reservoirs: Experimental approach and implications for magma

    E-print Network

    Long, Bernard

    on replenishment of rhyolite magma chambers by rhyolite magma using corn syrup-water solutions. We emphasize small ascent through the mush. Our results have implications for rhyolites bearing crystals with disequilibrium decades to investigate these processes. This study focuses on rhyolite magma replenishing rhyolite

  12. Laminar, Turbulent, and Inertial Shear-Thickening Regimes in Channel Flow of Neutrally Buoyant Particle Suspensions

    NASA Astrophysics Data System (ADS)

    Lashgari, Iman; Picano, Francesco; Breugem, Wim-Paul; Brandt, Luca

    2014-12-01

    The aim of this Letter is to characterize the flow regimes of suspensions of finite-size rigid particles in a viscous fluid at finite inertia. We explore the system behavior as a function of the particle volume fraction and the Reynolds number (the ratio of flow and particle inertia to viscous forces). Unlike single-phase flows, where a clear distinction exists between the laminar and the turbulent states, three different regimes can be identified in the presence of a particulate phase, with smooth transitions between them. At low volume fractions, the flow becomes turbulent when increasing the Reynolds number, transitioning from the laminar regime dominated by viscous forces to the turbulent regime characterized by enhanced momentum transport by turbulent eddies. At larger volume fractions, we identify a new regime characterized by an even larger increase of the wall friction. The wall friction increases with the Reynolds number (inertial effects) while the turbulent transport is weakly affected, as in a state of intense inertial shear thickening. This state may prevent the transition to a fully turbulent regime at arbitrary high speed of the flow.

  13. Meeting the Skills Needs of a Buoyant Economy: Apprenticeship--The Irish Experience

    ERIC Educational Resources Information Center

    O'Connor, Len

    2006-01-01

    The Irish economy has grown at an unprecedented rate over the last decade and the demand for skilled workers has increased dramatically. The Irish Standards-Based Apprenticeship (SBA) system has been one of the cornerstones of intermediate skills development with the capacity to produce high-quality craft workers and in sufficient numbers to meet…

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

    SciTech Connect

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

    1981-01-01

    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.

  15. A Buoyant Pop Net for Accurately Sampling Fish at Artificial Habitat Structures

    Microsoft Academic Search

    Eric W. Larson; David L. Johnson; William E. Lynch Jr

    1986-01-01

    We developed and evaluated the efficiency of a remotely operated pop net for sampling the entire fish assemblage associated with fish-attracting structures. The pop net collected an average of 99% of subadult and adult bluegills Lepomis macrochirus and largemouth bass Micropterus salmoides available to capture in pool tests conducted at 3–13°C and various light intensities. There was no evidence of

  16. The magnetic non-equilibrium of buoyant flux tubes in the solar corona

    NASA Technical Reports Server (NTRS)

    Browning, P. K.; Priest, E. R.

    1984-01-01

    The magnetic field in the convection zone and photosphere of the sun exists mostly as concentrated tubes of magnetic flux. It is, therefore, necessary to study the basic properties of magnetic flux tubes to obtain a basis for understanding the behavior of the sun's magnetic field. The present investigation is concerned with the global equilibrium shape of a flux tube in the stratified solar atmosphere. A fundamental property of isolated flux tubes is magnetic buoyancy. Attention is given to flux tubes with external field, and twisted flux tubes. It is shown that the analysis of Parker (1975, 1979) and Spruit (1981) for calculating the equilibrium of a slender flux tube in a stratified atmosphere may be extended to more general situations. The slender tube approximation provides a method of solving the problem of modeling the overall curvature of flux tubes. It is found that for a twisted flux tube, there can be two possible equilibrium values of the height.

  17. Preventing Buoyant Displacement Gas Release Events in Hanford Double-Shell Waste Tanks

    SciTech Connect

    Meyer, Perry A.; Stewart, Charles W.

    2001-01-01

    This report summarizes the predictive methods used to ensure that waste transfer operations in Hanford waste tanks do not create waste configurations that lead to unsafe gas release events. The gas release behavior of the waste in existing double-shell tanks has been well characterized, and the flammable gas safety issues associated with safe storage of waste in the current configuration are being formally resolved. However, waste is also being transferred between double-shell tanks and from single-shell tanks into double-shell tanks by saltwell pumping and sluicing that create new wastes and waste configurations that have not been studied as well. Additionally, planning is underway for various waste transfer scenarios to support waste feed delivery to the proposed vitrification plant. It is critical that such waste transfers do not create waste conditions with the potential for dangerous gas release events.

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

    E-print Network

    Hickey, Barbara

    acknowledged importance as a nutrient source, the Columbia River exhibits unusually low nitrate and N:Si levels, treatments consisting of control, added nitrate, and added nitrate with 0.45 mm filtered plume water were of these stations, nutrient (nitrate, ammonium, and ammonium inhibition of nitrate) kinetics were obtained, as well

  19. Sink fast and swim harder! Round-trip cost-of-transport for buoyant divers.

    PubMed

    Miller, Patrick J O; Biuw, Martin; Watanabe, Yuuki Y; Thompson, Dave; Fedak, Mike A

    2012-10-15

    Efficient locomotion between prey resources at depth and oxygen at the surface is crucial for breath-hold divers to maximize time spent in the foraging layer, and thereby net energy intake rates. The body density of divers, which changes with body condition, determines the apparent weight (buoyancy) of divers, which may affect round-trip cost-of-transport (COT) between the surface and depth. We evaluated alternative predictions from external-work and actuator-disc theory of how non-neutral buoyancy affects round-trip COT to depth, and the minimum COT speed for steady-state vertical transit. Not surprisingly, the models predict that one-way COT decreases (increases) when buoyancy aids (hinders) one-way transit. At extreme deviations from neutral buoyancy, gliding at terminal velocity is the minimum COT strategy in the direction aided by buoyancy. In the transit direction hindered by buoyancy, the external-work model predicted that minimum COT speeds would not change at greater deviations from neutral buoyancy, but minimum COT speeds were predicted to increase under the actuator disc model. As previously documented for grey seals, we found that vertical transit rates of 36 elephant seals increased in both directions as body density deviated from neutral buoyancy, indicating that actuator disc theory may more closely predict the power requirements of divers affected by gravity than an external work model. For both models, minor deviations from neutral buoyancy did not affect minimum COT speed or round-trip COT itself. However, at body-density extremes, both models predict that savings in the aided direction do not fully offset the increased COT imposed by the greater thrusting required in the hindered direction. PMID:23014571

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

    NASA Astrophysics Data System (ADS)

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

    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.

  1. 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...

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

    Microsoft Academic Search

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

    2012-01-01

    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

  3. Long-lived large-scale ground deformation caused by a buoyantly rising magma resevoir

    NASA Astrophysics Data System (ADS)

    Del Potro, R.; Diez, M.; Muller, C.; Perkins, J. P.; Finnegan, N. J.; Gottsmann, J.

    2013-12-01

    Recent InSAR studies have identified a constant, long-wavelength ground deformation pattern, comprising a central uplift and peripheral subsidence, centred on Uturuncu volcano in the Altiplano Puna Volcanic Complex of the Central Andes. This so-called 'sombrero uplift' has been consistent over the time scales of InSAR observations (1992-2010); however, it is unclear how long this deformation has persisted over the history of Uturuncu. Here we constrain the duration and causes of the ground deformation through a combination of available geodetic data, geomorphological studies and numerical modelling. GPS data from re-occupation of a nearby levelling line show that the observed ground deformation from 1965 to 2012 is compatible with the extent and the rate observed with InSAR, and thus suggests that the 'sombrero uplift' may have been constant for at least 50 years. In addition, from geomorphological measurements using shorelines from nearby lakes as inclinometers, we conclude that the total uplift of Uturuncu has not been more than 30 m, or that the constant ongoing uplift cannot have been active for more than 3000 years. Following our recent geophysical studies in the area, we explore the possibility that the observed ground deformation is caused by a rising felsic diapir and test this hypothesis numerically to show that the process is viable under these specific conditions, and accounts for the observed uplift rate. Our findings have significant implications for volcanologists inferring the characteristics of magma reservoirs from ground deformation data as it offers an alternative explanation of the causes driving ground deformation, and the growth and failure of magma reservoirs in a hot multiphase viscous crust.

  4. 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...

  5. Buoyant mixing of miscible fluids of varying viscosities in vertical tubes M. Debacq,a)

    E-print Network

    Hinch, John

    of such instabilities in a variety of domains: astrophysics and nuclear fusion,4,9 extraction col- umns in chemical at high viscosities and small tube diameters. For larger density contrasts, the flow is either convective at one of the ends of the tube which makes the corresponding boundary condition more complex

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

    Microsoft Academic Search

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

    2008-01-01

    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

  7. A buoyant tornado-probe concept incorporating an inverted lifting device. [and balloon combination

    NASA Technical Reports Server (NTRS)

    Grant, F. C.

    1973-01-01

    Addition of an inverted lifting device to a simple balloon probe is shown to make possible low-altitude entry to tornado cores with easier launch conditions than for the simple balloon probe. Balloon-lifter combinations are particularly suitable for penetration of tornadoes with average to strong circulation, but tornadoes of less than average circulation which are inaccessible to simple balloon probes become accessible. The increased launch radius which is needed for access to tornadoes over a wide range of circulation results in entry times of about 3 minutes. For a simple balloon probe the uninflated balloon must be first dropped on, or near, the track of the tornado from a safe distance. The increase in typical launch radius from about 0.75 kilometer to slightly over 1.0 kilometer with a balloon-lifter combination suggests that a direct air launch may be feasible.

  8. A numerical study of the release and dispersion of a buoyant gas in partially confined spaces

    Microsoft Academic Search

    K. Prasad; W. M. Pitts; J. C. Yang

    2011-01-01

    Development of the hydrogen economy will require a better understanding of the potential for fires and explosions associated with the unintended release of hydrogen within a structure. The ability to predict the mixing and dispersion behavior of hydrogen, when accidentally released in a partially confined space (e.g. hydrogen leak from automobiles parked in a residential garage) is critical to the

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

    ERIC Educational Resources Information Center

    Radovanovic, Jelena; Slisko, Josip

    2012-01-01

    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…

  10. 46 CFR 180.137 - Stowage of life floats and buoyant apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...deterioration from ultraviolet light; and (3) If metal, be corrosion resistant...deterioration from ultraviolet light. (e) If the vessel carries...painter: (1) The combined weight of each group of life...

  11. 46 CFR 117.137 - Stowage of life floats and buoyant apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...deterioration from ultraviolent light; and (3) If metal, be corrosion resistant...deterioration from ultraviolet light. (e) If the vessel carries...painter: (1) The combined weight of each group of life...

  12. Observations of the frontal region of a buoyant river plume using an autonomous underwater vehicle

    NASA Astrophysics Data System (ADS)

    Rogowski, Peter; Terrill, Eric; Chen, Jialin

    2014-11-01

    To characterize the transitional region from the near-field to far-field of a river plume entering coastal waters, we conducted four surveys using an autonomous underwater vehicle (AUV) to target the outflow of the New River Inlet, North Carolina, during maximum ebb tide. The utilization of a mobile sensor to synoptically observe current velocity data in tandem with natural river plume tracers (e.g., colored dissolved organic matter, salinity) was essential in understanding the mechanisms driving the observed circulation and mixing patterns within these waters. We find that this region is regularly impacted by two primary processes: (1) the interaction of an old dredged channel plume with the main discharge and (2) the recirculation of the discharge plume by an eddy that persistently forms between the old channel and main discharge location. Wind-driven processes in the nearshore can enhance the interaction of these two plumes resulting in unstable regions where mixing of the merged plume with the receiving waters is accelerated. We also conduct comparisons between AUV velocity observations from two surveys and their corresponding velocity outputs from a parallelized quasi-3-D model. We conclude that the ability to observe the estuarine outflow transitional region at near-synoptic temporal scales and resolutions discussed in this paper is key in providing the mechanisms driving local circulation which is essential for proper parameterization of high-resolution numerical coastal models.

  13. UTILITY OF BUOYANT PLUME MODELS IN PREDICTING THE INITIAL DILUTION OF DRILLING FLUIDS

    EPA Science Inventory

    Three computer programs, PLUME, OUTPLM, and DKHPLM, have been used by the U.S. Environmental Protection Agency and municipalities to estimate initial dilutions of sewage discharged into marine environments. odification of the input parameters for the three programs, while maintai...

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

    ERIC Educational Resources Information Center

    Neilson, Drew; Campbell, Todd; Allred, Benjamin

    2010-01-01

    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…

  15. Laminar, turbulent, and inertial shear-thickening regimes in channel flow of neutrally buoyant particle suspensions.

    PubMed

    Lashgari, Iman; Picano, Francesco; Breugem, Wim-Paul; Brandt, Luca

    2014-12-19

    The aim of this Letter is to characterize the flow regimes of suspensions of finite-size rigid particles in a viscous fluid at finite inertia. We explore the system behavior as a function of the particle volume fraction and the Reynolds number (the ratio of flow and particle inertia to viscous forces). Unlike single-phase flows, where a clear distinction exists between the laminar and the turbulent states, three different regimes can be identified in the presence of a particulate phase, with smooth transitions between them. At low volume fractions, the flow becomes turbulent when increasing the Reynolds number, transitioning from the laminar regime dominated by viscous forces to the turbulent regime characterized by enhanced momentum transport by turbulent eddies. At larger volume fractions, we identify a new regime characterized by an even larger increase of the wall friction. The wall friction increases with the Reynolds number (inertial effects) while the turbulent transport is weakly affected, as in a state of intense inertial shear thickening. This state may prevent the transition to a fully turbulent regime at arbitrary high speed of the flow. PMID:25554885

  16. Prostate cancer progression after androgen deprivation therapy: mechanisms of castrate resistance and novel therapeutic

    E-print Network

    Cai, Long

    Food and Drug Administration (FDA)-approved chemotherapies for the treatment of mCRPC (Table 1 benefits are modest.4 Another agent, sipuleucel-T (Provenge; Dendreon Corp., Seattle, WA, USA by patients who had failed chemotherapy.8 Moreover, according to a phase III clinical trial, abiraterone

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

    NASA Astrophysics Data System (ADS)

    Anderson, W. C.; Basu, S.

    2006-12-01

    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.

  18. Carbon and Water Program Protocols for Neutrally Buoyant Sediment Traps Twilight Zone Explorer at BATS, June 2007-December 2009

    E-print Network

    Buesseler, Ken

    , baffle, lid, and fishing wire and replace as needed · Load 350m screens into Teflon filter holders in laminar flow hood · Load equipment onto ship: o 5 tubes per trap + blank tube(s) + back-up spares o with the valve open o Close the valve and fill funnel with solution o Slowly open valve so that the flow

  19. A Semi-Analytic Model of a Buoyant Flame Bubble Propagation During the Deflagration Phase of a Type Ia Supernova

    NASA Astrophysics Data System (ADS)

    Jumper, Kevin; Fisher, Robert

    2012-03-01

    Type Ia supernovae are astronomical events in which a white dwarf, the cold remnant of a star that has exhausted its hydrogen fuel, detonates and briefly produces an explosion brighter than most galaxies. Many researchers think that they could occur as the white dwarf approaches a critical mass of 1.4 solar masses by accreting matter from a companion main sequence star, a scenario that is referred to as the single-degenerate channel. Assuming such a progenitor, we construct a semi-analytic model of the propagation of a flame bubble ignited at a single off-center point within the white dwarf. The bubble then rises under the influences of buoyancy and drag, burning the surrounding fuel material in a process called deflagration. We contrast the behavior of the deflagration phase in the presence of a physically high Reynolds number regime with the low Reynolds number regimes inherent to three-dimensional simulations, which are a consequence of numerical viscosity. Our work may help validate three-dimensional deflagration results over a range of initial conditions.

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

    SciTech Connect

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

    2010-04-15

    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)

  1. 46 CFR 160.047-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Materials-Dee ring and snap hook assemblies and other instruments...160.047-3a Materials—Dee ring and snap hook assemblies and other instruments of... (a) Specifications. Dee ring and snap lock assemblies and other...

  2. 46 CFR 160.052-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Materials-Dee ring and snap hook assemblies and other instruments...160.052-3a Materials—Dee ring and snap hook assemblies and other instruments of... (a) Specifications. Dee ring and snap hook assemblies and other...

  3. 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

    2011-10-01

    ...2011-10-01 false Materials-Dee ring and snap hook assemblies and other instruments...160.047-3a Materials—Dee ring and snap hook assemblies and other instruments of... (a) Specifications. Dee ring and snap lock assemblies and other...

  4. 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

    2011-10-01

    ...2011-10-01 false Materials-Dee ring and snap hook assemblies and other instruments...160.052-3a Materials—Dee ring and snap hook assemblies and other instruments of... (a) Specifications. Dee ring and snap hook assemblies and other...

  5. 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

    2012-10-01

    ...2012-10-01 false Materials-Dee ring and snap hook assemblies and other instruments...160.052-3a Materials—Dee ring and snap hook assemblies and other instruments of... (a) Specifications. Dee ring and snap hook assemblies and other...

  6. 46 CFR 160.047-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Materials-Dee ring and snap hook assemblies and other instruments...160.047-3a Materials—Dee ring and snap hook assemblies and other instruments of... (a) Specifications. Dee ring and snap lock assemblies and other...

  7. 46 CFR 160.052-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Materials-Dee ring and snap hook assemblies and other instruments...160.052-3a Materials—Dee ring and snap hook assemblies and other instruments of... (a) Specifications. Dee ring and snap hook assemblies and other...

  8. 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

    2012-10-01

    ...2012-10-01 false Materials-Dee ring and snap hook assemblies and other instruments...160.047-3a Materials—Dee ring and snap hook assemblies and other instruments of... (a) Specifications. Dee ring and snap lock assemblies and other...

  9. Potential migration of buoyant LNAPL from Intermediate Level Waste (ILW) emplaced in a geological disposal facility (GDF) for UK radioactive waste

    NASA Astrophysics Data System (ADS)

    Benbow, Steven J.; Rivett, Michael O.; Chittenden, Neil; Herbert, Alan W.; Watson, Sarah; Williams, Steve J.; Norris, Simon

    2014-10-01

    A safety case for the disposal of Intermediate Level (radioactive) Waste (ILW) in a deep geological disposal facility (GDF) requires consideration of the potential for waste-derived light non-aqueous phase liquid (LNAPL) to migrate under positive buoyancy from disposed waste packages. Were entrainment of waste-derived radionuclides in LNAPL to occur, such migration could result in a shorter overall travel time to environmental or human receptors than radionuclide migration solely associated with the movement of groundwater. This paper provides a contribution to the assessment of this issue through multiphase-flow numerical modelling underpinned by a review of the UK's ILW inventory and literature to define the nature of the associated ILW LNAPL source term. Examination has been at the waste package-local GDF environment scale to determine whether proposed disposal of ILW would lead to significant likelihood of LNAPL migration, both from waste packages and from a GDF vault into the local host rock. Our review and numerical modelling support the proposition that the release of a discrete free phase LNAPL from ILW would not present a significant challenge to the safety case even with conservative approximations. ‘As-disposed' LNAPL emplaced with the waste is not expected to pose a significant issue. ‘Secondary LNAPL' generated in situ within the disposed ILW, arising from the decomposition of plastics, in particular PVC (polyvinyl chloride), could form the predominant LNAPL source term. Released high molecular weight phthalate plasticizers are judged to be the primary LNAPL potentially generated. These are expected to have low buoyancy-based mobility due to their very low density contrast with water and high viscosity. Due to the inherent uncertainties, significant conservatisms were adopted within the numerical modelling approach, including: the simulation of a deliberately high organic material - PVC content wastestream (2D03) within an annular grouted waste package vulnerable to LNAPL release; upper bound inventory estimates of LNAPLs; incorporating the lack of any hydraulic resistance of the package vent; the lack of any degradation of dissolved LNAPL; and, significantly, the small threshold displacement pressure assumed at which LNAPL is able to enter initially water-saturated pores. Initial scoping calculations on the latter suggested that the rate at which LNAPL is able to migrate from a waste package is likely to be very small and insignificant for likely representative displacement pressure data: this represents a key result. Adopting a conservative displacement pressure, however, allowed the effect of other features and processes in the system to be assessed. High LNAPL viscosity together with low density contrast with water reduces LNAPL migration potential. Migration to the host rock is less likely if waste package vent fluxes are small, solubility limits are high and path lengths through the backfill are short. The capacity of the system to dissolve all of the free LNAPL will, however, depend on groundwater availability. Even with the conservatisms invoked, the overall conclusion of model simulations of intact and compromised (cracked or corroded) waste packages, for a range of realistic ILW LNAPL scenarios, is that it is unlikely that significant LNAPL would be able to migrate from the waste packages and even more unlikely it would be sufficiently persistent to reach the host rock immediately beyond the GDF.

  10. 46 CFR 160.052-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... false Materials-Dee ring and snap hook assemblies and other instruments of closure...052-3a Materials—Dee ring and snap hook assemblies and other instruments of closure...Specifications. Dee ring and snap hook assemblies and other instruments of...

  11. 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

    2010-10-01

    ... false Materials-Dee ring and snap hook assemblies and other instruments of closure...060-3a Materials—Dee ring and snap hook assemblies and other instruments of closure...Specifications. Dee ring and snap hook assemblies and other instruments of...

  12. 46 CFR 160.047-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... false Materials-Dee ring and snap hook assemblies and other instruments of closure...047-3a Materials—Dee ring and snap hook assemblies and other instruments of closure...Testing requirements. Dee ring and snap hook assemblies and other instruments of...

  13. Potential migration of buoyant LNAPL from intermediate level waste (ILW) emplaced in a geological disposal facility (GDF) for U.K. radioactive waste.

    PubMed

    Benbow, Steven J; Rivett, Michael O; Chittenden, Neil; Herbert, Alan W; Watson, Sarah; Williams, Steve J; Norris, Simon

    2014-10-15

    A safety case for the disposal of Intermediate Level (radioactive) Waste (ILW) in a deep geological disposal facility (GDF) requires consideration of the potential for waste-derived light non-aqueous phase liquid (LNAPL) to migrate under positive buoyancy from disposed waste packages. Were entrainment of waste-derived radionuclides in LNAPL to occur, such migration could result in a shorter overall travel time to environmental or human receptors than radionuclide migration solely associated with the movement of groundwater. This paper provides a contribution to the assessment of this issue through multiphase-flow numerical modelling underpinned by a review of the UK's ILW inventory and literature to define the nature of the associated ILW LNAPL source term. Examination has been at the waste package-local GDF environment scale to determine whether proposed disposal of ILW would lead to significant likelihood of LNAPL migration, both from waste packages and from a GDF vault into the local host rock. Our review and numerical modelling support the proposition that the release of a discrete free phase LNAPL from ILW would not present a significant challenge to the safety case even with conservative approximations. 'As-disposed' LNAPL emplaced with the waste is not expected to pose a significant issue. 'Secondary LNAPL' generated in situ within the disposed ILW, arising from the decomposition of plastics, in particular PVC (polyvinyl chloride), could form the predominant LNAPL source term. Released high molecular weight phthalate plasticizers are judged to be the primary LNAPL potentially generated. These are expected to have low buoyancy-based mobility due to their very low density contrast with water and high viscosity. Due to the inherent uncertainties, significant conservatisms were adopted within the numerical modelling approach, including: the simulation of a deliberately high organic material--PVC content wastestream (2D03) within an annular grouted waste package vulnerable to LNAPL release; upper bound inventory estimates of LNAPLs; incorporating the lack of any hydraulic resistance of the package vent; the lack of any degradation of dissolved LNAPL; and, significantly, the small threshold displacement pressure assumed at which LNAPL is able to enter initially water-saturated pores. Initial scoping calculations on the latter suggested that the rate at which LNAPL is able to migrate from a waste package is likely to be very small and insignificant for likely representative displacement pressure data: this represents a key result. Adopting a conservative displacement pressure, however, allowed the effect of other features and processes in the system to be assessed. High LNAPL viscosity together with low density contrast with water reduces LNAPL migration potential. Migration to the host rock is less likely if waste package vent fluxes are small, solubility limits are high and path lengths through the backfill are short. The capacity of the system to dissolve all of the free LNAPL will, however, depend on groundwater availability. Even with the conservatisms invoked, the overall conclusion of model simulations of intact and compromised (cracked or corroded) waste packages, for a range of realistic ILW LNAPL scenarios, is that it is unlikely that significant LNAPL would be able to migrate from the waste packages and even more unlikely it would be sufficiently persistent to reach the host rock immediately beyond the GDF. PMID:25147021

  14. 46 CFR 160.060-8 - Marking.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-8 Marking. ...tested in accordance with U.S. Coast Guard regulations. Polyethylene foam buoyant material provides a minimum buoyant force...

  15. 46 CFR 160.060-8 - Marking.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-8 Marking. ...tested in accordance with U.S. Coast Guard regulations. Polyethylene foam buoyant material provides a minimum buoyant force...

  16. 46 CFR 160.060-8 - Marking.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-8 Marking. ...tested in accordance with U.S. Coast Guard regulations. Polyethylene foam buoyant material provides a minimum buoyant force...

  17. 30 CFR 250.910 - Which of my facilities are subject to the Platform Verification Program?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (1) Your new floating platform is a buoyant...following associated structures: (i) Drilling... (2) Your new floating platform is a buoyant...Only the following structures that may be associated with a floating platform are...

  18. 30 CFR 250.910 - Which of my facilities are subject to the Platform Verification Program?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (1) Your new floating platform is a buoyant...following associated structures: (i) Drilling... (2) Your new floating platform is a buoyant...Only the following structures that may be associated with a floating platform are...

  19. 30 CFR 250.910 - Which of my facilities are subject to the Platform Verification Program?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (1) Your new floating platform is a buoyant...following associated structures: (i) Drilling... (2) Your new floating platform is a buoyant...Only the following structures that may be associated with a floating platform are...

  20. 30 CFR 250.910 - Which of my facilities are subject to the Platform Verification Program?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (1) Your new floating platform is a buoyant...following associated structures: (i) Drilling... (2) Your new floating platform is a buoyant...Only the following structures that may be associated with a floating platform are...

  1. 30 CFR 250.910 - Which of my facilities are subject to the Platform Verification Program?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (1) Your new floating platform is a buoyant...following associated structures: (i) Drilling... (2) Your new floating platform is a buoyant...Only the following structures that may be associated with a floating platform are...

  2. 46 CFR 160.052-1 - Incorporation by reference.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

  3. 46 CFR 160.049-1 - Incorporation by reference.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

  4. 46 CFR 160.052-1 - Incorporation by reference.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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

  5. 46 CFR 28.130 - Survival craft equipment.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Service”); or (3) SOLAS A Pack (formerly “Ocean Service”). (c) Each life float and buoyant apparatus must be fitted with...survival craft other than inflatable liferafts, life floats, inflatable buoyant apparatus,...

  6. 46 CFR 28.130 - Survival craft equipment.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Service”); or (3) SOLAS A Pack (formerly “Ocean Service”). (c) Each life float and buoyant apparatus must be fitted with...survival craft other than inflatable liferafts, life floats, inflatable buoyant apparatus,...

  7. 46 CFR 28.130 - Survival craft equipment.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Service”); or (3) SOLAS A Pack (formerly “Ocean Service”). (c) Each life float and buoyant apparatus must be fitted with...survival craft other than inflatable liferafts, life floats, inflatable buoyant apparatus,...

  8. 46 CFR 28.130 - Survival craft equipment.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Service”); or (3) SOLAS A Pack (formerly “Ocean Service”). (c) Each life float and buoyant apparatus must be fitted with...survival craft other than inflatable liferafts, life floats, inflatable buoyant apparatus,...

  9. 46 CFR 160.171-9 - Construction.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL...meets the buoyancy and thermal insulation requirements in...o). (i) Buoyant materials and compartments. Buoyant materials used in a suit must...

  10. 46 CFR 160.171-9 - Construction.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL...meets the buoyancy and thermal insulation requirements in...o). (i) Buoyant materials and compartments. Buoyant materials used in a suit must...

  11. 46 CFR 160.171-9 - Construction.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL...meets the buoyancy and thermal insulation requirements in...o). (i) Buoyant materials and compartments. Buoyant materials used in a suit must...

  12. 46 CFR 160.171-9 - Construction.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL...meets the buoyancy and thermal insulation requirements in...o). (i) Buoyant materials and compartments. Buoyant materials used in a suit must...

  13. 46 CFR 160.060-2 - Type and model.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-2 Type and model. Each buoyant vest specified in this subpart is a:...

  14. 46 CFR 160.060-6 - Construction-nonstandard vests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-6 Construction...nonstandard vest must contain the following volume of unicellular polyethylene foam buoyant material, determined by the displacement...

  15. 46 CFR 160.060-6 - Construction-nonstandard vests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-6 Construction...nonstandard vest must contain the following volume of unicellular polyethylene foam buoyant material, determined by the displacement...

  16. 46 CFR 160.060-1 - Incorporation by reference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-1 Incorporation...Coast Guard Specification: 164.013—Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal Pattern) (b)...

  17. 46 CFR 160.060-6 - Construction-nonstandard vests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-6 Construction...nonstandard vest must contain the following volume of unicellular polyethylene foam buoyant material, determined by the displacement...

  18. 46 CFR 160.060-1 - Incorporation by reference.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-1 Incorporation...Coast Guard Specification: 164.013—Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal Pattern) (b)...

  19. 46 CFR 160.060-2 - Type and model.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-2 Type and model. Each buoyant vest specified in this subpart is a:...

  20. 46 CFR 160.060-2 - Type and model.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-2 Type and model. Each buoyant vest specified in this subpart is a:...

  1. 46 CFR 160.060-2 - Type and model.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-2 Type and model. Each buoyant vest specified in this subpart is a:...

  2. 46 CFR 160.060-6 - Construction-nonstandard vests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-6 Construction...nonstandard vest must contain the following volume of unicellular polyethylene foam buoyant material, determined by the displacement...

  3. 46 CFR 160.060-2 - Type and model.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-2 Type and model. Each buoyant vest specified in this subpart is a:...

  4. 46 CFR 160.060-6 - Construction-nonstandard vests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-6 Construction...nonstandard vest must contain the following volume of unicellular polyethylene foam buoyant material, determined by the displacement...

  5. 46 CFR 160.052-1 - Incorporation by reference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

  6. 46 CFR 160.052-1 - Incorporation by reference.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  7. 46 CFR 160.049-1 - Incorporation by reference.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  8. 46 CFR 160.049-1 - Incorporation by reference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

  9. 33 CFR 175.23 - Serviceable condition.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...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...

  10. 33 CFR 175.23 - Serviceable condition.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...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...

  11. 46 CFR 131.540 - Operational readiness.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...ach lifesaving appliance and each item of equipment for a lifeboat, liferaft, survival craft, rescue boat, life float, or buoyant...b) Each deck where a lifeboat, liferaft, survival craft, rescue boat, life float, or buoyant...

  12. 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...

  13. 46 CFR 164.013-5 - Acceptance tests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...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...

  14. 46 CFR 164.013-5 - Acceptance tests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...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...

  15. 46 CFR 164.013-5 - Acceptance tests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...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...

  16. 46 CFR 164.013-7 - Marking.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...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...

  17. 46 CFR 164.013-7 - Marking.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...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...

  18. 46 CFR 164.013-7 - Marking.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...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...

  19. 46 CFR 164.013-2 - Incorporation by reference.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL MATERIALS Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal Pattern) § 164.013-2 Incorporation by reference. (a) Certain...

  20. 46 CFR 164.013-7 - Marking.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...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...

  1. 46 CFR 164.013-5 - Acceptance tests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...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...

  2. 46 CFR 164.013-4 - Samples submitted for acceptance.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...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...

  3. 46 CFR 164.013-2 - Incorporation by reference.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL MATERIALS Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal Pattern) § 164.013-2 Incorporation by reference. (a) Certain...

  4. 46 CFR 164.013-4 - Samples submitted for acceptance.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...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...

  5. 46 CFR 164.013-2 - Incorporation by reference.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL MATERIALS Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal Pattern) § 164.013-2 Incorporation by reference. (a) Certain...

  6. 46 CFR 164.013-4 - Samples submitted for acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...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...

  7. 46 CFR 164.013-7 - Marking.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...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...

  8. 46 CFR 164.013-5 - Acceptance tests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...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...

  9. 46 CFR 164.013-4 - Samples submitted for acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...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...

  10. 46 CFR 164.013-4 - Samples submitted for acceptance.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...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...

  11. Low-velocity flows through plasmas

    Microsoft Academic Search

    B W Walsh

    1972-01-01

    Calculations are presented for the estimation of the fraction of an incoming gas flow that passes through a plasma volume which is subject to buoyant forces. The method of analysis is an extension of that proposed by Lawton for the zero-gravity case. It is shown that buoyant forces are significant in determining the mass fraction of gas flowing through low-velocity

  12. 46 CFR 160.048-1 - Incorporation by reference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Specification for a Buoyant Cushion, Fibrous Glass § 160.048-1 Incorporation by reference...specification: MIL-B-2766—Batt, Fibrous Glass, Lifesaving Equipment. (2) Federal...issue in effect on the date kapok or fibrous glass buoyant cushions are manufactured,...

  13. 46 CFR 160.048-7 - Procedure for approval.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Specification for a Buoyant Cushion, Fibrous Glass § 160.048-7 Procedure for approval...and which are filled with kapok or fibrous glass in accordance with § 160.048-4(c...manufacturer for each kapok or fibrous glass buoyant cushion he proposes to...

  14. 46 CFR 160.048-7 - Procedure for approval.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Specification for a Buoyant Cushion, Fibrous Glass § 160.048-7 Procedure for approval...and which are filled with kapok or fibrous glass in accordance with § 160.048-4(c...manufacturer for each kapok or fibrous glass buoyant cushion he proposes to...

  15. 46 CFR 160.048-7 - Procedure for approval.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Specification for a Buoyant Cushion, Fibrous Glass § 160.048-7 Procedure for approval...and which are filled with kapok or fibrous glass in accordance with § 160.048-4(c...manufacturer for each kapok or fibrous glass buoyant cushion he proposes to...

  16. 46 CFR 160.048-7 - Procedure for approval.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Specification for a Buoyant Cushion, Fibrous Glass § 160.048-7 Procedure for approval...and which are filled with kapok or fibrous glass in accordance with § 160.048-4(c...manufacturer for each kapok or fibrous glass buoyant cushion he proposes to...

  17. 46 CFR 160.048-1 - Incorporation by reference.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Specification for a Buoyant Cushion, Fibrous Glass § 160.048-1 Incorporation by reference...specification: MIL-B-2766—Batt, Fibrous Glass, Lifesaving Equipment. (2) Federal...issue in effect on the date kapok or fibrous glass buoyant cushions are manufactured,...

  18. 46 CFR 160.048-7 - Procedure for approval.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Specification for a Buoyant Cushion, Fibrous Glass § 160.048-7 Procedure for approval...and which are filled with kapok or fibrous glass in accordance with § 160.048-4(c...manufacturer for each kapok or fibrous glass buoyant cushion he proposes to...

  19. The gas content and buoyancy of strombolian ash plumes

    Microsoft Academic Search

    Matthew Patrick

    2007-01-01

    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,

  20. Partial specific volume and solvent interactions of amphipol A8-35 Yann Gohona

    E-print Network

    ) of the buoyant molar masses of particles in D2O and H2O solutions, obtained from sedimentation velocity (s. Measurements of density, sD/sH buoyant molar masses in H2O, D2O, and D2 18 O, and CMP of hydrogenated ultracentrifugation; Density; Small-angle neutron scattering Membrane proteins constitute about one-third

  1. Development of floating rafts after the rewetting of cut-over bogs: the importance of peat quality

    Microsoft Academic Search

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

    2005-01-01

    The usual method of restoring cut-over bogs is to rewet the peat surface, but this often leads to the remaining peat layers being deeply inundated. For Sphagnum-dominated vegetation to develop at deeply inundated locations, it is important for floating rafts of buoyant residual peat to develop. In this study, the chemical and physical characteristics of buoyant and inundated peat collected

  2. 46 CFR 25.25-5 - Life preservers and other lifesaving equipment required.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...an immersion suit for a life preserver, buoyant vest...may be substituted for a life preserver, buoyant vest...not within an enclosed space. [CGD 72-172R...follows: § 25.25-5 Life preservers and other lifesaving equipment...

  3. 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...

  4. 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 ...

  5. Emergent, long-lived Gondwanaland vs. submergent, short-lived Laurasia: Supercontinental and Pan-African heat imparts long-term buoyancy by mafic underplating

    Microsoft Academic Search

    J. J. Veevers

    1995-01-01

    Gondwanaland was buoyant, as indicated by nonmarine facies, and Laurasia was depressed, as indicated by marine facies. As a supercontinent, Gondwanaland lasted much longer than Laurasia and was hotter from internal heat. Moreover, the Pan-African orogenic cycle, confined to Gondwanaland, augmented the heat supply, which possibly generated a permanently buoyant lower crust by underplating. A crustal layer in the Australian

  6. 46 CFR 160.064-3 - Requirements. 1

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...device to a boat. The arrangement of the buoyancy of devices intended to be worn...resistant or treated for mildew resistance. Buoyancy shall be provided by inherently buoyant...inflation. So long as the minimum required buoyancy is provided by inherently buoyant...

  7. 46 CFR 160.052-5 - Construction-standard vests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...in which are enclosed inserts of buoyant material arranged and distributed so as to provide the flotation characteristics and buoyancy required to hold the wearer in an upright or slightly backward position with head and face out of water. The buoyant...

  8. 46 CFR 160.060-5 - Construction-standard vests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...in which are enclosed inserts of buoyant material arranged and distributed so as to provide the flotation characteristics and buoyancy required to hold the wearer in an upright or slightly backward position with head and face out of water. The buoyant...

  9. 46 CFR 160.064-3 - Requirements. 1

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...device to a boat. The arrangement of the buoyancy of devices intended to be worn...resistant or treated for mildew resistance. Buoyancy shall be provided by inherently buoyant...inflation. So long as the minimum required buoyancy is provided by inherently buoyant...

  10. 46 CFR 160.064-3 - Requirements. 1

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...device to a boat. The arrangement of the buoyancy of devices intended to be worn...resistant or treated for mildew resistance. Buoyancy shall be provided by inherently buoyant...inflation. So long as the minimum required buoyancy is provided by inherently buoyant...

  11. 46 CFR 160.064-3 - Requirements. 1

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...device to a boat. The arrangement of the buoyancy of devices intended to be worn...resistant or treated for mildew resistance. Buoyancy shall be provided by inherently buoyant...inflation. So long as the minimum required buoyancy is provided by inherently buoyant...

  12. 46 CFR 160.052-5 - Construction-standard vests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...in which are enclosed inserts of buoyant material arranged and distributed so as to provide the flotation characteristics and buoyancy required to hold the wearer in an upright or slightly backward position with head and face out of water. The buoyant...

  13. 46 CFR 160.064-3 - Requirements. 1

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...device to a boat. The arrangement of the buoyancy of devices intended to be worn...resistant or treated for mildew resistance. Buoyancy shall be provided by inherently buoyant...inflation. So long as the minimum required buoyancy is provided by inherently buoyant...

  14. 46 CFR 160.073-1 - Scope.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...APPROVAL LIFESAVING EQUIPMENT Float-Free Link or Life Floats and Buoyant Apparatus ...contains requirements for a float-free link used for connecting a life float or buoyant...apparatus painter to a vessel. The float-free link is designed to be broken by the...

  15. 46 CFR 160.073-20 - Marking.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...APPROVAL LIFESAVING EQUIPMENT Float-Free Link or Life Floats and Buoyant Apparatus § 160.073-20 Marking. (a) Each link certified by the manufacturer to meet...the indicated space): FLOAT-FREE LINK FOR LIFE FLOATS AND BUOYANT APPARATUS...

  16. 46 CFR 160.073-1 - Scope.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...APPROVAL LIFESAVING EQUIPMENT Float-Free Link or Life Floats and Buoyant Apparatus ...contains requirements for a float-free link used for connecting a life float or buoyant...apparatus painter to a vessel. The float-free link is designed to be broken by the...

  17. 46 CFR 160.073-20 - Marking.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...APPROVAL LIFESAVING EQUIPMENT Float-Free Link or Life Floats and Buoyant Apparatus § 160.073-20 Marking. (a) Each link certified by the manufacturer to meet...the indicated space): FLOAT-FREE LINK FOR LIFE FLOATS AND BUOYANT APPARATUS...

  18. 46 CFR 160.073-20 - Marking.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...APPROVAL LIFESAVING EQUIPMENT Float-Free Link or Life Floats and Buoyant Apparatus § 160.073-20 Marking. (a) Each link certified by the manufacturer to meet...the indicated space): FLOAT-FREE LINK FOR LIFE FLOATS AND BUOYANT APPARATUS...

  19. 46 CFR 160.073-1 - Scope.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...APPROVAL LIFESAVING EQUIPMENT Float-Free Link or Life Floats and Buoyant Apparatus ...contains requirements for a float-free link used for connecting a life float or buoyant...apparatus painter to a vessel. The float-free link is designed to be broken by the...

  20. 46 CFR 160.073-1 - Scope.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...APPROVAL LIFESAVING EQUIPMENT Float-Free Link or Life Floats and Buoyant Apparatus ...contains requirements for a float-free link used for connecting a life float or buoyant...apparatus painter to a vessel. The float-free link is designed to be broken by the...

  1. 46 CFR 160.073-20 - Marking.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...APPROVAL LIFESAVING EQUIPMENT Float-Free Link or Life Floats and Buoyant Apparatus § 160.073-20 Marking. (a) Each link certified by the manufacturer to meet...the indicated space): FLOAT-FREE LINK FOR LIFE FLOATS AND BUOYANT APPARATUS...

  2. 46 CFR 160.073-1 - Scope.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...APPROVAL LIFESAVING EQUIPMENT Float-Free Link or Life Floats and Buoyant Apparatus ...contains requirements for a float-free link used for connecting a life float or buoyant...apparatus painter to a vessel. The float-free link is designed to be broken by the...

  3. 46 CFR 160.073-20 - Marking.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...APPROVAL LIFESAVING EQUIPMENT Float-Free Link or Life Floats and Buoyant Apparatus § 160.073-20 Marking. (a) Each link certified by the manufacturer to meet...the indicated space): FLOAT-FREE LINK FOR LIFE FLOATS AND BUOYANT APPARATUS...

  4. Clinical Development of Listeria monocytogenes–Based Immunotherapies

    PubMed Central

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

    2013-01-01

    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

  5. Parametric study of modern airship productivity

    NASA Technical Reports Server (NTRS)

    Ardema, M. D.; Flaig, K.

    1980-01-01

    A method for estimating the specific productivity of both hybrid and fully buoyant airships is developed. Various methods of estimating structural weight of deltoid hybrids are discussed and a derived weight estimating relationship is presented. Specific productivity is used as a figure of merit in a parametric study of fully buoyant ellipsoidal and deltoid hybrid semi-buoyant vehicles. The sensitivity of results as a function of assumptions is also determined. No airship configurations were found to have superior specific productivity to transport airplanes.

  6. A Tale of Two Spills: Novel Science and Policy Implications of an Emerging New Oil Spill Model

    E-print Network

    Adams, E. Eric

    The 2010 Deepwater Horizon oil release posed the challenges of two types of spill: a familiar spill characterized by buoyant oil, fouling and killing organisms at the sea surface and eventually grounding on and damaging ...

  7. 46 CFR 164.015-3 - Material and workmanship.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...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...

  8. 46 CFR 160.049-3 - Materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-3 Materials. (a) General...requirements of subpart 164.019. (b) Unicellular plastic foam. The unicellular plastic foam shall be all new material complying...

  9. 46 CFR 164.015-5 - Procedure for acceptance.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...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...

  10. 46 CFR 160.049-3 - Materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-3 Materials. (a) General...requirements of subpart 164.019. (b) Unicellular plastic foam. The unicellular plastic foam shall be all new material complying...

  11. 46 CFR 160.049-3 - Materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-3 Materials. (a) General...requirements of subpart 164.019. (b) Unicellular plastic foam. The unicellular plastic foam shall be all new material complying...

  12. 46 CFR 164.015-5 - Procedure for acceptance.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...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...

  13. 46 CFR 164.015-3 - Material and workmanship.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...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...

  14. 46 CFR 160.052-3 - Materials-standard vests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Specification for a Buoyant Vest, Unicellular Plastic Foam, Adult and Child § 160.052-3 Materials...in the finished product. (b) Unicellular plastic foam. The unicellular plastic foam shall be all new material complying...

  15. 46 CFR 160.052-3 - Materials-standard vests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Specification for a Buoyant Vest, Unicellular Plastic Foam, Adult and Child § 160.052-3 Materials...in the finished product. (b) Unicellular plastic foam. The unicellular plastic foam shall be all new material complying...

  16. 46 CFR 164.015-3 - Material and workmanship.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...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...

  17. 46 CFR 164.015-5 - Procedure for acceptance.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...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...

  18. 46 CFR 160.052-3 - Materials-standard vests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Specification for a Buoyant Vest, Unicellular Plastic Foam, Adult and Child § 160.052-3 Materials...in the finished product. (b) Unicellular plastic foam. The unicellular plastic foam shall be all new material complying...

  19. Carbon dioxide hydrate particles for ocean carbon sequestration

    E-print Network

    Chow, A.C.

    This paper presents strategies for producing negatively buoyant CO[subscript 2] hydrate composite particles for ocean carbon sequestration. Our study is based on recent field observations showing that a continuous-jet ...

  20. Sooting Behaviour Dynamics of a Non-Bouyant Laminar Diffusion Flame 

    E-print Network

    Fuentes, Andres; Legros, Guillaume; Rouvreau, Sebastien; Joulain, Pierre; Vantelon, Jean-Pierre; Torero, Jose L; Fernandez-Pello, Carlos

    2007-01-01

    Local soot concentrations in non-buoyant laminar diffusion flames have been demonstrated to be the outcome of two competitive processes, soot formation and soot oxidation. It was first believed that soot formation was the ...

  1. 46 CFR 160.047-3 - Materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Specification for a Buoyant Vest, Kapok or Fibrous Glass, Adult and Child § 160.047-3 Materials...and shall be properly processed. (c) Fibrous glass. The fibrous glass shall comply with the requirements of...

  2. 46 CFR 160.005-4 - Construction.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...LIFESAVING EQUIPMENT Life Preservers, Fibrous Glass, Adult and Child (Jacket Type), Models...sealing, and distribution of fibrous glass. The buoyant pad inserts shall...pad inserts shall be filled with fibrous glass distributed as follows: Table...

  3. 46 CFR 160.048-3 - Materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...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...

  4. 46 CFR 160.047-3 - Materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Specification for a Buoyant Vest, Kapok or Fibrous Glass, Adult and Child § 160.047-3 Materials...and shall be properly processed. (c) Fibrous glass. The fibrous glass shall comply with the requirements of...

  5. 46 CFR 160.047-3 - Materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Specification for a Buoyant Vest, Kapok or Fibrous Glass, Adult and Child § 160.047-3 Materials...and shall be properly processed. (c) Fibrous glass. The fibrous glass shall comply with the requirements of...

  6. 46 CFR 160.005-4 - Construction.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...LIFESAVING EQUIPMENT Life Preservers, Fibrous Glass, Adult and Child (Jacket Type), Models...sealing, and distribution of fibrous glass. The buoyant pad inserts shall...pad inserts shall be filled with fibrous glass distributed as follows: Table...

  7. 46 CFR 160.047-3 - Materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Specification for a Buoyant Vest, Kapok or Fibrous Glass, Adult and Child § 160.047-3 Materials...and shall be properly processed. (c) Fibrous glass. The fibrous glass shall comply with the requirements of...

  8. 46 CFR 160.005-4 - Construction.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...LIFESAVING EQUIPMENT Life Preservers, Fibrous Glass, Adult and Child (Jacket Type), Models...sealing, and distribution of fibrous glass. The buoyant pad inserts shall...pad inserts shall be filled with fibrous glass distributed as follows: Table...

  9. 46 CFR 160.047-3 - Materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Specification for a Buoyant Vest, Kapok or Fibrous Glass, Adult and Child § 160.047-3 Materials...and shall be properly processed. (c) Fibrous glass. The fibrous glass shall comply with the requirements of...

  10. 46 CFR 160.048-3 - Materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...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...

  11. Sedimentation Of Oil-MIneral Aggregates For Remediation Of Vegetable Oil Spills

    EPA Science Inventory

    A response alternative for floating vegetable oil spills based on sedimentation of negatively buoyant oil-mineral aggregrates followed by anaerobic biodegradation in the sediments is under investigation. Sedimentation of floating canola oil by interaction with montmorillonite wa...

  12. 46 CFR 160.010-2 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...the Commandant (CG-ENG-4), Attn: Lifesaving and Fire Safety Division, U.S. Coast Guard Stop 7509, 2703 Martin Luther King Jr. Avenue SE., Washington, DC 20593-7509. Peripheral-body. Peripheral body is buoyant apparatus...

  13. 46 CFR 160.010-2 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...the Commandant (CG-ENG-4), Attn: Lifesaving and Fire Safety Division, U.S. Coast Guard Stop 7509, 2703 Martin Luther King Jr. Avenue SE., Washington, DC 20593-7509. Peripheral-body. Peripheral body is buoyant apparatus...

  14. ELSEVIER Journal of Crystal Growth 179 (1997)297-308 j........ CRYSTAL

    E-print Network

    Walker, D. Greg

    component PVT systems. A continuum-based model, which includes buoyancy and Soret diffusion, is developed on buoyant convection, and on the Soret transport of the vapor, are examined. PACS: 81.15; 02.60; 44

  15. Mineralogy: Garnet goes hungry

    NASA Astrophysics Data System (ADS)

    Bina, Craig R.

    2013-05-01

    Sinking slabs of oceanic lithosphere often stagnate in Earth's mantle. Experiments show that common slab minerals transform to their high-pressure, high-density counterparts at very slow rates, thus keeping the slabs buoyant and impeding subduction.

  16. 46 CFR 160.060-3 - Materials-standard vests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-3...the finished product. (b) Unicellular polyethylene foam. The unicellular polyethylene foam shall be all new material...

  17. 46 CFR 164.013-6 - Production tests, inspections, and marking.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...SPECIFICATIONS AND APPROVAL MATERIALS Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal Pattern) § 164.013-6...Manufacturers shall provide in-plant quality control of polyethylene foam in accordance with the requirements of §...

  18. 46 CFR 160.060-3 - Materials-standard vests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-3...the finished product. (b) Unicellular polyethylene foam. The unicellular polyethylene foam shall be all new material...

  19. 46 CFR 160.060-9 - Recognized laboratory.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-9 Recognized laboratory. (a) A manufacturer seeking Coast Guard...

  20. 46 CFR 164.013-6 - Production tests, inspections, and marking.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...SPECIFICATIONS AND APPROVAL MATERIALS Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal Pattern) § 164.013-6...Manufacturers shall provide in-plant quality control of polyethylene foam in accordance with the requirements of §...

  1. 46 CFR 160.060-3 - Materials-standard vests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-3...the finished product. (b) Unicellular polyethylene foam. The unicellular polyethylene foam shall be all new material...

  2. 46 CFR 160.060-3 - Materials-standard vests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-3...the finished product. (b) Unicellular polyethylene foam. The unicellular polyethylene foam shall be all new material...

  3. 46 CFR 160.060-4 - Materials-nonstandard vests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-4 Materials—nonstandard vests. (a) General. All materials used...

  4. 46 CFR 160.060-4 - Materials-nonstandard vests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-4 Materials—nonstandard vests. (a) General. All materials used...

  5. 46 CFR 160.060-3 - Materials-standard vests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-3...the finished product. (b) Unicellular polyethylene foam. The unicellular polyethylene foam shall be all new material...

  6. 46 CFR 164.013-1 - Scope.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...APPROVAL MATERIALS Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal...testing and inspection requirements for polyethylene foam used in the construction of...019 of this chapter. (b) All polyethylene foams accepted under this subpart...

  7. 46 CFR 164.013-6 - Production tests, inspections, and marking.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...SPECIFICATIONS AND APPROVAL MATERIALS Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal Pattern) § 164.013-6...Manufacturers shall provide in-plant quality control of polyethylene foam in accordance with the requirements of §...

  8. 46 CFR 164.013-3 - Material properties and workmanship.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...APPROVAL MATERIALS Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal... (a) General. The unicellular polyethylene foam shall be all new material complying...in this specification. Unicellular polyethylene foam must comply with the...

  9. 46 CFR 164.013-6 - Production tests, inspections, and marking.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...SPECIFICATIONS AND APPROVAL MATERIALS Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal Pattern) § 164.013-6...Manufacturers shall provide in-plant quality control of polyethylene foam in accordance with the requirements of §...

  10. 46 CFR 160.060-9 - Recognized laboratory.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-9 Recognized laboratory. (a) A manufacturer seeking Coast Guard...

  11. 46 CFR 164.013-3 - Material properties and workmanship.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...APPROVAL MATERIALS Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal... (a) General. The unicellular polyethylene foam shall be all new material complying...in this specification. Unicellular polyethylene foam must comply with the...

  12. 46 CFR 160.060-5 - Construction-standard vests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-5 Construction—standard vests. (a) General. This...

  13. 46 CFR 160.060-9 - Recognized laboratory.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-9 Recognized laboratory. (a) A manufacturer seeking Coast Guard...

  14. 46 CFR 164.013-3 - Material properties and workmanship.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...APPROVAL MATERIALS Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal... (a) General. The unicellular polyethylene foam shall be all new material complying...in this specification. Unicellular polyethylene foam must comply with the...

  15. 46 CFR 160.060-4 - Materials-nonstandard vests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-4 Materials—nonstandard vests. (a) General. All materials used...

  16. 46 CFR 160.060-5 - Construction-standard vests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-5 Construction—standard vests. (a) General. This...

  17. 46 CFR 164.013-3 - Material properties and workmanship.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...APPROVAL MATERIALS Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal... (a) General. The unicellular polyethylene foam shall be all new material complying...in this specification. Unicellular polyethylene foam must comply with the...

  18. 46 CFR 160.060-4 - Materials-nonstandard vests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-4 Materials—nonstandard vests. (a) General. All materials used...

  19. 46 CFR 160.060-5 - Construction-standard vests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-5 Construction—standard vests. (a) General. This...

  20. 46 CFR 164.013-1 - Scope.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...APPROVAL MATERIALS Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal...testing and inspection requirements for polyethylene foam used in the construction of...019 of this chapter. (b) All polyethylene foams accepted under this subpart...

  1. 46 CFR 164.013-1 - Scope.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...APPROVAL MATERIALS Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal...testing and inspection requirements for polyethylene foam used in the construction of...019 of this chapter. (b) All polyethylene foams accepted under this subpart...

  2. 46 CFR 164.013-1 - Scope.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...APPROVAL MATERIALS Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal...testing and inspection requirements for polyethylene foam used in the construction of...019 of this chapter. (b) All polyethylene foams accepted under this subpart...

  3. 46 CFR 164.013-1 - Scope.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...APPROVAL MATERIALS Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal...testing and inspection requirements for polyethylene foam used in the construction of...019 of this chapter. (b) All polyethylene foams accepted under this subpart...

  4. 46 CFR 164.013-3 - Material properties and workmanship.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...APPROVAL MATERIALS Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal... (a) General. The unicellular polyethylene foam shall be all new material complying...in this specification. Unicellular polyethylene foam must comply with the...

  5. 46 CFR 160.060-9 - Recognized laboratory.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-9 Recognized laboratory. (a) A manufacturer seeking Coast Guard...

  6. 46 CFR 160.060-5 - Construction-standard vests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-5 Construction—standard vests. (a) General. This...

  7. 46 CFR 164.013-6 - Production tests, inspections, and marking.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...SPECIFICATIONS AND APPROVAL MATERIALS Foam, Unicellular Polyethylene (Buoyant, Slab, Slitted Trigonal Pattern) § 164.013-6...Manufacturers shall provide in-plant quality control of polyethylene foam in accordance with the requirements of §...

  8. 46 CFR 160.060-4 - Materials-nonstandard vests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-4 Materials—nonstandard vests. (a) General. All materials used...

  9. 46 CFR 160.060-9 - Recognized laboratory.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-9 Recognized laboratory. (a) A manufacturer seeking Coast Guard...

  10. 46 CFR 160.064-4 - Marking.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...160.064-4 Marking. (a) Each water safety buoyant device must have the following information clearly marked in waterproof lettering: (1) For devices to be worn: (Type II or Type III) Personal Flotation Device. Inspected and...

  11. 46 CFR 160.064-4 - Marking.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...160.064-4 Marking. (a) Each water safety buoyant device must have the following information clearly marked in waterproof lettering: (1) For devices to be worn: (Type II or Type III) Personal Flotation Device. Inspected and...

  12. 46 CFR 160.047-6 - Marking.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...following information clearly marked in waterproof lettering that can be read at a distance...distributor.). (Lot No.). (b) Waterproof marking tags. Marking for buoyant vests shall be sufficiently waterproof so that after 72 hours...

  13. 46 CFR 160.052-8 - Marking.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...following information clearly marked in waterproof lettering that can be read at a distance...distributor). (Lot No.) (b) Waterproof marking. Marking for buoyant vests shall be sufficiently waterproof so that after 72 hours...

  14. 46 CFR 160.060-8 - Marking.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...following information clearly marked in waterproof lettering: Type II Personal Flotation...distributor). (Lot No.). (b) Waterproof marking. Marking of buoyant vests shall be sufficiently waterproof so that after 72 hours...

  15. 46 CFR 160.060-8 - Marking.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...following information clearly marked in waterproof lettering: Type II Personal Flotation...distributor). (Lot No.). (b) Waterproof marking. Marking of buoyant vests shall be sufficiently waterproof so that after 72 hours...

  16. 46 CFR 160.047-6 - Marking.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...following information clearly marked in waterproof lettering that can be read at a distance...distributor.). (Lot No.). (b) Waterproof marking tags. Marking for buoyant vests shall be sufficiently waterproof so that after 72 hours...

  17. 46 CFR 160.052-8 - Marking.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...following information clearly marked in waterproof lettering that can be read at a distance...distributor). (Lot No.) (b) Waterproof marking. Marking for buoyant vests shall be sufficiently waterproof so that after 72 hours...

  18. 14 CFR 91.509 - Survival equipment for overwater operations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...off an airplane for flight over water more than 30 minutes flying time...liferaft. (4) One self-buoyant, water-resistant, portable emergency radio signaling...this section for a particular over water operation or the...

  19. Reprinted from The Tectonic and Geologic Evolution of Southeast Asian Seas and Islands-Geophysical Monograph 23

    E-print Network

    McCaffrey, Robert

    . The overall similarity between travel time curves coupled with anomalous travel times on the scale of a few].Complica- incorporated into the collision complex along thrust sur- tions arise, however, when buoyant

  20. 33 CFR 181.4 - Incorporation by reference.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...in this part, and the sections affected are: Underwriters Laboratories, Inc. (UL) 12 Laboratory Drive, Research Triangle Park, NC 27709-3995 UL 1123, Marine Buoyant Devices, 181.703. February 17, 1995. [CGD 81-023, 55 FR...

  1. 33 CFR 181.4 - Incorporation by reference.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...in this part, and the sections affected are: Underwriters Laboratories, Inc. (UL) 12 Laboratory Drive, Research Triangle Park, NC 27709-3995 UL 1123, Marine Buoyant Devices, 181.703. February 17, 1995. [CGD 81-023, 55 FR...

  2. Coherent Structures and Larval Transport in the California Current System

    E-print Network

    Harrison, Cheryl S.

    2012-01-01

    LCS act as transport barriers for passive particles andpassive or buoyant floaters (Metaxas 2011), making the dispersal of these planktonic organisms a natural application problem for chaotic Lagrangian transport

  3. Energy Procedia 00 (2010) 000000 www.elsevier.com/locate/XXX

    E-print Network

    Wildenschild, Dorthe

    and fault systems. Despite very broad research efforts by industry, government, and academic groups injection stops, buoyant forces will continue to propel the CO2 upwards, while brine reoccupies the pore

  4. Mantle Dynamics, Early Reservoir Formation and Degassing of the Martian Interior

    NASA Astrophysics Data System (ADS)

    Breuer, D.; Plesa, A.-C.; Grott, M.; Morschhauser, A.

    2014-11-01

    Inefficient volcanic outgassing of the interior supports the hypothesis that rather than being warm-and-wet, the martian climate was probably cold-and-wet. The formation of a buoyant depleted mantle layer prevents efficient outgassing of water.

  5. 15 CFR 772.1 - Definitions of terms as used in the Export Administration Regulations (EAR).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...foreign government. Airship . (Cat 9) A power-driven airborne vehicle that is kept buoyant...of the target in real time. Average Output Power . (Cat 6) The average output power is the total “laser” output energy, in...

  6. 15 CFR 772.1 - Definitions of terms as used in the Export Administration Regulations (EAR).

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...foreign government. Airship. (Cat 9) A power-driven airborne vehicle that is kept buoyant...of the target in real time. Average Output Power. (Cat 6) The average output power is the total “laser” output energy, in...

  7. 46 CFR 160.052-3 - Materials-standard vests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...Specification for a Buoyant Vest, Unicellular Plastic Foam, Adult and Child § 160.052-3 Materials...in the finished product. (b) Unicellular plastic foam. The unicellular plastic foam shall be all new material complying...

  8. 46 CFR 160.049-3 - Materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-3 Materials. (a) General...requirements of subpart 164.019. (b) Unicellular plastic foam. The unicellular plastic foam shall be all new material complying...

  9. 46 CFR 164.015-5 - Procedure for acceptance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...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...

  10. 46 CFR 164.015-3 - Material and workmanship.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...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...

  11. 46 CFR 164.015-3 - Material and workmanship.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...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...

  12. 46 CFR 160.052-3 - Materials-standard vests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Specification for a Buoyant Vest, Unicellular Plastic Foam, Adult and Child § 160.052-3 Materials...in the finished product. (b) Unicellular plastic foam. The unicellular plastic foam shall be all new material complying...

  13. 46 CFR 160.049-3 - Materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-3 Materials. (a) General...requirements of subpart 164.019. (b) Unicellular plastic foam. The unicellular plastic foam shall be all new material complying...

  14. 46 CFR 164.015-5 - Procedure for acceptance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...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...

  15. Intracellular Water Exchange for Measuring the Dry Mass, Water Mass and Changes in Chemical Composition of Living Cells

    E-print Network

    Cermak, Nathan

    We present a method for direct non-optical quantification of dry mass, dry density and water mass of single living cells in suspension. Dry mass and dry density are obtained simultaneously by measuring a cell’s buoyant ...

  16. Carbon flow and ecosystem dynamics in the Mississippi River plume described by inverse analysis

    E-print Network

    Breed, Greg Allen

    2002-01-01

    Planktonic ecosystem dynamics in the buoyant Mississippi River plume were investigated using inverse analysis, a technique that incorporates data describing ecosystem processes and calculates rates of unknown trophic flows and sedimentation...

  17. 46 CFR 26.30-1 - Approved unicellular plastic foam work vests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    (a) Buoyant work vests carried under the permissive authority of this subpart shall be of an approved type, and shall be constructed, listed, and labeled in accordance with subpart 160.053 of subchapter Q (Specifications) of this...

  18. 46 CFR 26.30-1 - Approved unicellular plastic foam work vests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    (a) Buoyant work vests carried under the permissive authority of this subpart shall be of an approved type, and shall be constructed, listed, and labeled in accordance with subpart 160.053 of subchapter Q (Specifications) of this...

  19. 46 CFR 26.30-1 - Approved unicellular plastic foam work vests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    (a) Buoyant work vests carried under the permissive authority of this subpart shall be of an approved type, and shall be constructed, listed, and labeled in accordance with subpart 160.053 of subchapter Q (Specifications) of this...

  20. 46 CFR 26.30-1 - Approved unicellular plastic foam work vests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    (a) Buoyant work vests carried under the permissive authority of this subpart shall be of an approved type, and shall be constructed, listed, and labeled in accordance with subpart 160.053 of subchapter Q (Specifications) of this...

  1. 46 CFR 26.30-1 - Approved unicellular plastic foam work vests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    (a) Buoyant work vests carried under the permissive authority of this subpart shall be of an approved type, and shall be constructed, listed, and labeled in accordance with subpart 160.053 of subchapter Q (Specifications) of this...

  2. Experimental study of gravitation effects in the flow of a particle-laden thin film on an inclined plane

    E-print Network

    Ward, Thomas

    The flow of viscous, particle-laden wetting thin films on an inclined plane is studied experimentally as the particle concentration is increased to the maximum packing limit. The slurry is a non-neutrally buoyant mixture ...

  3. Turbulent round jet under gravity waves

    E-print Network

    Ryu, Yong Uk

    2002-01-01

    The behavior of a neutrally buoyant horizontal turbulent round jet under a wavy environment was investigated. Progressive waves with different wave amplitudes in an intermediate water depth were used. The Particle Image Velocimetry (PIV) technique...

  4. FLOCCULATION-FLOTATION AIDS FOR TREATMENT OF COMBINED SEWER OVERFLOWS

    EPA Science Inventory

    The objectives of this study were to investigate the flocculation/flotation characteristics of combined sewer overflow through laboratory and field testing. The concept involves the introduction of chemicals and buoyant flotation aids into the overflow and the subsequent cofloccu...

  5. Soil Liquefaction–Induced Uplift of Underground Structures: Physical and Numerical Modeling

    E-print Network

    Chian, Siau Chen; Tokimatsu, Kohji; M.ASCE; Madabhushi, Santana Phani Gopal

    2014-07-11

    observed in the field. A simplified mechanism for the floatation of a circular un- derground structure is portrayed in Fig. 1. The buoyant force of the structure (FB) is governed by the Archimedes principle. This buoyancy force is equivalent...

  6. Buoyancy and Archimedes Principle

    NSDL National Science Digital Library

    Summary Buoyancy is based on Archimedes' Principle which states that the buoyant force acting upward on an object completely or partially immersed in a fluid equals the weight of the fluid displaced by the ...

  7. 11th International Conference on Fluid Control, Measurements and Visualization11th International Conference on Fluid Control, Measurements and Visualization FLUCOME 2011

    E-print Network

    Garbe, Christoph S.

    National Taiwan Ocean University, Keelung, Taiwan Figure 1 Buoyant jet [CR08] Figure 2 Deepwater Horizon] and submarine images from the Deepwater Hori- zon oil spill (see Figure 2). The results were also compared

  8. 46 CFR 160.005-5 - Sampling, tests, and inspections.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...with this section and § 160.001-5. (b) Buoyancy test. The buoyancy of the pad inserts from the life preserver shall...submersion must be at least 48 hours. (c) Buoyancy required. The buoyant pad inserts from...

  9. 46 CFR 160.002-5 - Sampling, tests, and inspections.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...with this section and § 160.001-5. (b) Buoyancy test. The buoyancy of the pad inserts from the life preserver shall...submersion must be at least 48 hours. (c) Buoyancy required. The buoyant pad inserts from...

  10. 46 CFR 160.176-23 - Marking.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...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...

  11. 46 CFR 160.005-5 - Sampling, tests, and inspections.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...with this section and § 160.001-5. (b) Buoyancy test. The buoyancy of the pad inserts from the life preserver shall...submersion must be at least 48 hours. (c) Buoyancy required. The buoyant pad inserts from...

  12. 46 CFR 160.005-5 - Sampling, tests, and inspections.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...with this section and § 160.001-5. (b) Buoyancy test. The buoyancy of the pad inserts from the life preserver shall...submersion must be at least 48 hours. (c) Buoyancy required. The buoyant pad inserts from...

  13. 46 CFR 160.055-7 - Sampling, tests, and inspections.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...with this section and § 160.001-5. (b) Buoyancy test. The buoyancy of the pad inserts from the life preserver shall...submersion must be at least 48 hours. (c) Buoyancy required. The buoyant pad inserts from...

  14. 46 CFR 160.002-5 - Sampling, tests, and inspections.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...with this section and § 160.001-5. (b) Buoyancy test. The buoyancy of the pad inserts from the life preserver shall...submersion must be at least 48 hours. (c) Buoyancy required. The buoyant pad inserts from...

  15. 46 CFR 160.055-7 - Sampling, tests, and inspections.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...with this section and § 160.001-5. (b) Buoyancy test. The buoyancy of the pad inserts from the life preserver shall...submersion must be at least 48 hours. (c) Buoyancy required. The buoyant pad inserts from...

  16. 46 CFR 160.027-2 - Type.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...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)...

  17. 46 CFR 160.077-2 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...buoyant material. (e) Inflation medium means any solid, liquid, or gas, that, when activated, provides inflation for buoyancy. (f) Inspector means an independent laboratory representative assigned to perform duties described in §...

  18. 46 CFR 160.027-2 - Type.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...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)...

  19. 46 CFR 160.055-7 - Sampling, tests, and inspections.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...with this section and § 160.001-5. (b) Buoyancy test. The buoyancy of the pad inserts from the life preserver shall...submersion must be at least 48 hours. (c) Buoyancy required. The buoyant pad inserts from...

  20. 46 CFR 160.053-4 - Inspections and tests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...have on hand the necessary apparatus for conducting buoyancy tests in compliance with this specification...undergoing tests or change in water level. (e) Buoyancy —(1) Buoyancy test method. Remove the buoyant inserts...

  1. 46 CFR 160.053-4 - Inspections and tests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...have on hand the necessary apparatus for conducting buoyancy tests in compliance with this specification...undergoing tests or change in water level. (e) Buoyancy —(1) Buoyancy test method. Remove the buoyant inserts...

  2. 46 CFR 160.056-2 - Construction.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...The rescue boat shall be fitted with three thwarts. The middle thwart shall be arranged as the rowing seat. (e) Internal buoyancy. Buoyant material of suitable unicellular plastic foam shall be installed in the rescue boat. This material...

  3. 46 CFR 160.005-5 - Sampling, tests, and inspections.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...with this section and § 160.001-5. (b) Buoyancy test. The buoyancy of the pad inserts from the life preserver shall...submersion must be at least 48 hours. (c) Buoyancy required. The buoyant pad inserts from...

  4. 46 CFR 160.053-4 - Inspections and tests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...have on hand the necessary apparatus for conducting buoyancy tests in compliance with this specification...undergoing tests or change in water level. (e) Buoyancy —(1) Buoyancy test method. Remove the buoyant inserts...

  5. 46 CFR 160.055-7 - Sampling, tests, and inspections.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...with this section and § 160.001-5. (b) Buoyancy test. The buoyancy of the pad inserts from the life preserver shall...submersion must be at least 48 hours. (c) Buoyancy required. The buoyant pad inserts from...

  6. 46 CFR 160.053-4 - Inspections and tests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...have on hand the necessary apparatus for conducting buoyancy tests in compliance with this specification...undergoing tests or change in water level. (e) Buoyancy —(1) Buoyancy test method. Remove the buoyant inserts...

  7. 46 CFR 160.002-5 - Sampling, tests, and inspections.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...with this section and § 160.001-5. (b) Buoyancy test. The buoyancy of the pad inserts from the life preserver shall...submersion must be at least 48 hours. (c) Buoyancy required. The buoyant pad inserts from...

  8. 46 CFR 160.077-2 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...buoyant material. (e) Inflation medium means any solid, liquid, or gas, that, when activated, provides inflation for buoyancy. (f) Inspector means an independent laboratory representative assigned to perform duties described in §...

  9. 46 CFR 160.053-4 - Inspections and tests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...have on hand the necessary apparatus for conducting buoyancy tests in compliance with this specification...undergoing tests or change in water level. (e) Buoyancy —(1) Buoyancy test method. Remove the buoyant inserts...

  10. 46 CFR 160.005-5 - Sampling, tests, and inspections.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...with this section and § 160.001-5. (b) Buoyancy test. The buoyancy of the pad inserts from the life preserver shall...submersion must be at least 48 hours. (c) Buoyancy required. The buoyant pad inserts from...

  11. 46 CFR 160.002-5 - Sampling, tests, and inspections.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...with this section and § 160.001-5. (b) Buoyancy test. The buoyancy of the pad inserts from the life preserver shall...submersion must be at least 48 hours. (c) Buoyancy required. The buoyant pad inserts from...

  12. 46 CFR 160.002-5 - Sampling, tests, and inspections.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...with this section and § 160.001-5. (b) Buoyancy test. The buoyancy of the pad inserts from the life preserver shall...submersion must be at least 48 hours. (c) Buoyancy required. The buoyant pad inserts from...

  13. 46 CFR 160.055-7 - Sampling, tests, and inspections.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...with this section and § 160.001-5. (b) Buoyancy test. The buoyancy of the pad inserts from the life preserver shall...submersion must be at least 48 hours. (c) Buoyancy required. The buoyant pad inserts from...

  14. 46 CFR 160.027-2 - Type.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...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)...

  15. Finite element analysis of floatation of rectangular tunnels following earthquake induced liquefaction

    E-print Network

    Madabhushi, S. S. C.; Madabhushi, S. P. G.

    2014-10-29

    Underground structures such as tunnels, pipelines, car parks etc. can suffer severe damage during strong earthquake events. As many of these structures are buoyant, soil liquefaction due to earthquake loading can result in their floatation...

  16. 46 CFR 160.060-7 - Inspections and tests-standard and nonstandard vests. 1

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...conduct an examination, test and inspection of a buoyant...applicable requirements. (d) Test facilities. The manufacturer shall admit the laboratory inspector and the Coast Guard...Examine, inspect, or test a sample of a part or...

  17. 46 CFR 160.052-7 - Inspections and tests-standard and nonstandard vests. 1

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...conduct an examination, test and inspection of a buoyant...applicable requirements. (d) Test facilities. The manufacturer shall admit the laboratory inspector and the Coast Guard...Examine, inspect, or test a sample of a part or...

  18. 46 CFR 160.073-5 - Certification.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...APPROVAL LIFESAVING EQUIPMENT Float-Free Link or Life Floats and Buoyant Apparatus ...Certification. (a) The float-free link is not approved by the Coast Guard. The manufacturer of the link must certify that it meets all of the...

  19. 46 CFR 160.073-10 - Construction and performance.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... LIFESAVING EQUIPMENT Float-Free Link or Life Floats and Buoyant Apparatus...Construction and performance. (a) The link must be constructed essentially as shown in figure 160.073-10. The link must be formed from a single salt...

  20. 46 CFR 160.073-10 - Construction and performance.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... LIFESAVING EQUIPMENT Float-Free Link or Life Floats and Buoyant Apparatus...Construction and performance. (a) The link must be constructed essentially as shown in figure 160.073-10. The link must be formed from a single salt...

  1. 46 CFR 160.073-10 - Construction and performance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... LIFESAVING EQUIPMENT Float-Free Link or Life Floats and Buoyant Apparatus...Construction and performance. (a) The link must be constructed essentially as shown in figure 160.073-10. The link must be formed from a single salt...

  2. 46 CFR 160.073-5 - Certification.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...APPROVAL LIFESAVING EQUIPMENT Float-Free Link or Life Floats and Buoyant Apparatus ...Certification. (a) The float-free link is not approved by the Coast Guard. The manufacturer of the link must certify that it meets all of the...

  3. 46 CFR 160.073-5 - Certification.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...APPROVAL LIFESAVING EQUIPMENT Float-Free Link or Life Floats and Buoyant Apparatus ...Certification. (a) The float-free link is not approved by the Coast Guard. The manufacturer of the link must certify that it meets all of the...

  4. 46 CFR 160.073-10 - Construction and performance.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... LIFESAVING EQUIPMENT Float-Free Link or Life Floats and Buoyant Apparatus...Construction and performance. (a) The link must be constructed essentially as shown in figure 160.073-10. The link must be formed from a single salt...

  5. 46 CFR 160.073-10 - Construction and performance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... LIFESAVING EQUIPMENT Float-Free Link or Life Floats and Buoyant Apparatus...Construction and performance. (a) The link must be constructed essentially as shown in figure 160.073-10. The link must be formed from a single salt...

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

    NASA Technical Reports Server (NTRS)

    Delisi, Donald P.; Greene, George C.

    1990-01-01

    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.

  7. Buoyancy Bulls-Eye

    NSDL National Science Digital Library

    California Academy of Sciences

    2008-01-01

    In this hands-on activity, learners will construct a scuba diver that can float in order to explore how sea creatures stay neutrally buoyant in the ocean and to see what kinds of forces might be influencing their buoyancy. By adding materials such as balloons, rubber bands, toothpicks, pennies, etc. to their figure, they will try to make it neutrally buoyant in a bucket of water. This lesson plan includes discussion questions, key vocabulary, and is standards-based.

  8. Operational considerations for the airship in short-haul transportation

    NASA Technical Reports Server (NTRS)

    Walker, C. D.

    1975-01-01

    The airship's problems and the possibilities for their solution in a short-haul transportation environment are surveyed. The problems are derived from both past experience and envisioned operation. Problems relative to both fully buoyant and semi-buoyant configurations are considered and their origins in principle discussed. Also addressed in this paper are the state-of-the-art technologies with the potential of providing answers to the airship's operational difficulties.

  9. Feasibility study of modern airships, phase 2. Volume 1: Heavy lift airship vehicle. Book 1: Overall study results

    NASA Technical Reports Server (NTRS)

    1976-01-01

    A Heavy Lift Airship combining buoyant lift derived from a conventional helium-filled non-rigid airship hull with propulsive lift derived from conventional helicopter rotors was investigated. The buoyant lift essentially offsets the empty weight of the vehicle; thus the rotor thrust is available for useful load and to maneuver and control the vehicle. Such a vehicle is capable of providing a quantum increase in current vertical lifting capability. Certain critical deficiencies of past airships are significantly minimized or eliminated.

  10. Floating rings in vertical soap films : capillary driven bidimensional buoyancy

    E-print Network

    Adami, N

    2013-01-01

    The present study aims to investigate the motion of buoyant rings in vertical soap films. Thickness differences and related bi-dimensional densities are considered as the motor leading to bi-dimensional buoyancy. We show how this effect can be re-interpreted thanks to surface tension profiles in soap films. We propose a model involving surface tension profiles in order to describe the motion of buoyant particles in vertical soap films, and compare it to experimental data.

  11. Investigation of the free flow electrophoretic process. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Weiss, R. A.; Lanham, J. W.; Richman, D. W.; Walker, C. D.

    1979-01-01

    The effect of gravity on the free flow electrophoretic process was investigated. The demonstrated effects were then compared with predictions made by mathematical models. Results show that the carrier buffer flow was affected by gravity induced thermal convection and that the movement of the separating particle streams was affected by gravity induced buoyant forces. It was determined that if gravity induced buoyant forces were included in the mathematical models, then effective predictions of electrophoresis chamber separation performance were possible.

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

    NASA Astrophysics Data System (ADS)

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

    2012-11-01

    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.

  13. A Yarmouthian molluscan fauna in the mid-continent region of the United States

    E-print Network

    Leonard, A. B.

    1950-03-24

    . Shells of terrestrial mollusks almost in-variably appear in these deposits, also. Presumably, these shells were washed or blown in from nearbyslopes or possibly from greater distances, since such shells are very buoyant when air is trapped withinthem. A.... Shells of terrestrial mollusks almost in-variably appear in these deposits, also. Presumably, these shells were washed or blown in from nearbyslopes or possibly from greater distances, since such shells are very buoyant when air is trapped withinthem. A...

  14. The stability of buoyancy-driven coastal currents

    Microsoft Academic Search

    R. W. GRIFFITHS; P. F. LINDEN

    1981-01-01

    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

  15. Translational Approaches towards Cancer Gene Therapy: Hurdles and Hopes

    PubMed Central

    Barar, Jaleh; Omidi, Yadollah

    2012-01-01

    Introduction Of the cancer gene therapy approaches, gene silencing, suicide/apoptosis inducing gene therapy, immunogene therapy and targeted gene therapy are deemed to sub-stantially control the biological consequences of genomic changes in cancerous cells. Thus, a large number of clinical trials have been conducted against various malignancies. In this review, we will discuss recent translational progresses of gene and cell therapy of cancer. Methods Essential information on gene therapy of cancer were reviewed and discussed towards their clinical translations. Results Gene transfer has been rigorously studied in vitro and in vivo, in which some of these gene therapy endeavours have been carried on towards translational investigations and clinical applications. About 65% of gene therapy trials are related to cancer therapy. Some of these trials have been combined with cell therapy to produce personalized medicines such as Sipuleucel-T (Provenge®, marketed by Dendreon, USA) for the treatment of asymptomatic/minimally symptomatic metastatic hormone-refractory prostate cancer. Conclusion Translational approach links two diverse boundaries of basic and clinical researches. For successful translation of geno-medicines into clinical applications, it is essential 1) to have the guidelines and standard operating procedures for development and application of the genomedicines specific to clinically relevant biomarker(s); 2) to conduct necessary animal experimental studies to show the “proof of concept” for the proposed genomedicines; 3) to perform an initial clinical investigation; and 4) to initiate extensive clinical trials to address all necessary requirements. In short, translational researches need to be refined to accelerate the geno-medicine development and clinical applications. PMID:23678451

  16. Computer aided airship design

    NASA Technical Reports Server (NTRS)

    Davis, S. J.; Rosenstein, H.

    1975-01-01

    The Comprehensive Airship Sizing and Performance Computer Program (CASCOMP) is described which was developed and used in the design and evaluation of advanced lighter-than-air (LTA) craft. The program defines design details such as engine size and number, component weight buildups, required power, and the physical dimensions of airships which are designed to meet specified mission requirements. The program is used in a comparative parametric evaluation of six advanced lighter-than-air concepts. The results indicate that fully buoyant conventional airships have the lightest gross lift required when designed for speeds less than 100 knots and the partially buoyant concepts are superior above 100 knots. When compared on the basis of specific productivity, which is a measure of the direct operating cost, the partially buoyant lifting body/tilting prop-rotor concept is optimum.

  17. Feasibility of modern airships - Design definition and performance of selected concepts

    NASA Technical Reports Server (NTRS)

    Huston, R. R.; Ardema, M. D.

    1977-01-01

    Three promising modern airship system concepts and their associated missions were studied: (1) a heavy-lift airship, employing a nonrigid hull and a significant amount of rotor lift, used for short-range transporting and positioning of heavy military and civil payloads; (2) a VTOL (vertical take-off and landing), metal-clad, partially buoyant airship used as a short-haul commercial transport; (3) a fully-buoyant airship used for long-endurance Navy missions. The heavy-lift airship concept offers a dramatic increase in vertical lift capability over existing systems at significantly lower costs per ton-mile. The VTOL airship transport concept appears to be economically competititve with other VTOL aircraft concepts but can attain significantly lower noise levels. The fully-buoyant airship concept can provide an airborne platform with long endurance that satisfies many Navy mission requirements.

  18. Feasibility study of modern airships. Phase 2: Executive summary

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A feasibility study of modern airships has been completed. Three promising modern airship systems' concepts and their associated missions were studied; (1) a heavy-lift airship, employing a non-rigid hull and a significant amount of rotor lift, used for short-range transport and positioning of heavy military and civil payloads, (2) a VTOL (vertical take-off and landing), metalclad, partially buoyant airship used as a short-haul commercial transport; and (3) a class of fully-buoyant airships used for long-endurance Navy missions. The heavy-lift airship concept offers a substantial increase in vertical lift capability over existing systems and is projected to have lower total operating costs per ton-mile. The VTOL airship transport concept appears to be economically competitive with other VTOL aircraft concepts but can attain significantly lower noise levels. The fully-buoyant airship concept can provide an airborne platform with long endurance that satisfies many Navy mission requirements.

  19. Mass and density measurements of live and dead Gram-negative and Gram-positive bacterial populations.

    PubMed

    Lewis, Christina L; Craig, Caelli C; Senecal, Andre G

    2014-06-01

    Monitoring cell growth and measuring physical features of food-borne pathogenic bacteria are important for better understanding the conditions under which these organisms survive and proliferate. To address this challenge, buoyant masses of live and dead Escherichia coli O157:H7 and Listeria innocua were measured using Archimedes, a commercially available suspended microchannel resonator (SMR). Cell growth was monitored with Archimedes by observing increased cell concentration and buoyant mass values of live growing bacteria. These growth data were compared to optical density measurements obtained with a Bioscreen system. We observed buoyant mass measurements with Archimedes at cell concentrations between 10(5) and 10(8) cells/ml, while growth was not observed with optical density measurements until the concentration was 10(7) cells/ml. Buoyant mass measurements of live and dead cells with and without exposure to hydrogen peroxide stress were also compared; live cells generally had a larger buoyant mass than dead cells. Additionally, buoyant mass measurements were used to determine cell density and total mass for both live and dead cells. Dead E. coli cells were found to have a larger density and smaller total mass than live E. coli cells. In contrast, density was the same for both live and dead L. innocua cells, while the total mass was greater for live than for dead cells. These results contribute to the ongoing challenge to further develop existing technologies used to observe cell populations at low concentrations and to measure unique physical features of cells that may be useful for developing future diagnostics. PMID:24705320

  20. Mass and Density Measurements of Live and Dead Gram-Negative and Gram-Positive Bacterial Populations

    PubMed Central

    Craig, Caelli C.; Senecal, Andre G.

    2014-01-01

    Monitoring cell growth and measuring physical features of food-borne pathogenic bacteria are important for better understanding the conditions under which these organisms survive and proliferate. To address this challenge, buoyant masses of live and dead Escherichia coli O157:H7 and Listeria innocua were measured using Archimedes, a commercially available suspended microchannel resonator (SMR). Cell growth was monitored with Archimedes by observing increased cell concentration and buoyant mass values of live growing bacteria. These growth data were compared to optical density measurements obtained with a Bioscreen system. We observed buoyant mass measurements with Archimedes at cell concentrations between 105 and 108 cells/ml, while growth was not observed with optical density measurements until the concentration was 107 cells/ml. Buoyant mass measurements of live and dead cells with and without exposure to hydrogen peroxide stress were also compared; live cells generally had a larger buoyant mass than dead cells. Additionally, buoyant mass measurements were used to determine cell density and total mass for both live and dead cells. Dead E. coli cells were found to have a larger density and smaller total mass than live E. coli cells. In contrast, density was the same for both live and dead L. innocua cells, while the total mass was greater for live than for dead cells. These results contribute to the ongoing challenge to further develop existing technologies used to observe cell populations at low concentrations and to measure unique physical features of cells that may be useful for developing future diagnostics. PMID:24705320

  1. Determination of Bacterial Antibiotic Resistance Based on Osmotic Shock Response

    PubMed Central

    Knudsen, Scott M.; von Muhlen, Marcio G.; Schauer, David B.; Manalis, Scott R.

    2014-01-01

    We investigate the buoyant mass of bacterial cells in real time with the suspended microchannel resonator (SMR) as the population recovers from an osmotic shock. The density of the culture medium is chosen such that the bacteria initially have a positive buoyant mass which becomes negative as they recover from the hyperosmotic stress. This behavior can be used to differentiate between an antibiotic-resistant and an antibiotic-susceptible strain of the pathogenic bacteria Citrobacter rodentium, and we propose a general approach for exploiting the high precision of the SMR for rapid detection of antibiotic resistance. PMID:20337387

  2. LTA structures and materials technology. [airships

    NASA Technical Reports Server (NTRS)

    Mayer, N. J.

    1975-01-01

    The state-of-the-art concerning structures and materials technology is reviewed. It is shown that many present materials developments resulting from balloon and aircraft research programs can be applied to new concepts in LTA vehicles. Both buoyant and semi-buoyant vehicles will utilize similar approaches to solving structural problems and could involve pressurized non-rigid and unpressurized rigid structures. System designs common to both and vital to structural integrity will include much of the past technology as well. Further research is needed in determination of structural loads, especially in future design concepts.

  3. Cartesian Divers

    NSDL National Science Digital Library

    This activity gives students a hands-on look at the effects of increased water pressure and shows them how submarines work. Using a balloon and plastic water bottle, students create a neutrally buoyant diver. Then they squeeze the bottle to see how increased pressure compresses the balloon, making it heavier and causing it to sink. The activity includes an extension that has students further explore how animals use their swim bladders to dive and rise. Students can find out with a balloon and a bottle of water how a submarine, which is buoyant to start with, becomes heavier and dives down into the water.

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

    Microsoft Academic Search

    G. A. Rose; D. R. Porter

    1996-01-01

    (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)

  5. Boundary Current Eddies and Their Role in the Restratification of the Labrador Sea

    Microsoft Academic Search

    Caroline A. Katsman; Michael A. Spall; Robert S. Pickart

    2004-01-01

    An idealized model is used to study the restratification of the Labrador Sea after deep convection, with emphasis on the role of boundary current eddies shed near the west coast of Greenland. The boundary current eddies carry warm, buoyant Irminger Current water into the Labrador Sea interior. For a realistic end-of-winter state, it is shown that these Irminger Current eddies

  6. Pattern formation driven by an acid-base neutralization reaction in aqueous media in a gravitational field

    Microsoft Academic Search

    A. Zalts; C. El Hasi; D. Rubio; A. Ureña; A. D'Onofrio

    2008-01-01

    We report the hydrodynamic instabilities found in a simple exothermic neutralization reaction. Although the heavier aqueous NaOH solution was put below the lighter layer of aqueous HCl solution, fingering at the interface in a Hele-Shaw cell was observed. The reaction front, which propagates downward, becomes buoyantly unstable in the gravity field. The mixing zone length and wave number depend on

  7. SOFAR floats for POLYMODE

    Microsoft Academic Search

    Douglas C. Webb

    1977-01-01

    The design of a neutrally buoyant float and associated tracking and support equipment developed for the POLYMODE experiment is described. Floats with a signaling range of 1500 Km and an endurance of 2-1\\/2 years signal via the deep sound channel to both land based receiving stations and moored, portable receivers. Recordings of float signals are collected and centrally processed, providing

  8. Floating behaviour in the tellinid bivalve Macoma balthica (L.)

    Microsoft Academic Search

    Tommy Siirlin

    1988-01-01

    The tellinid bivalve Macoma balthica from the Dutch Wadden Sea mudflats achieved secondary distribution by a floating behaviour after stimulation by low ambient temperature in slow-moving sea water (salinity 25‰). Floating behaviour among responding mussels began with burrowing displacements as their foot was directed towards the sediment surface. After extreme protrusion of the foot they became buoyant and were able

  9. 46 CFR 160.060-1 - Incorporation by reference.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... MIL-W-530F-Webbing, Textile, Cotton, General Purpose...Federal Standards: No. 191-Textile Test Methods. No. 751A-Stitches...Buoyant, Slab, Slitted Trigonal Pattern) (b) Plans. The...060-1: Sheet 1—Cutting Pattern and General Arrangement,...

  10. Nonarbo-togaviridae: Comparative hydrodynamic properties of the pestivirus genus

    Microsoft Academic Search

    H. Laude

    1979-01-01

    Summary The sedimentation coefficient and buoyant density of hog cholera, bovine viral diarrhea and Border disease viruses, have been compared with those of representative members of the family togaviridae. It appears that the pestivirus genus is a homogeneous group which is not only antigenically but also structurally, unrelated to the other genera of the togavirus family.

  11. Limitations and Functions: Four Examples of Integrating Thermodynamics

    ERIC Educational Resources Information Center

    Chang, Wheijen

    2011-01-01

    Physics students are usually unaware of the limitations and functions of related principles, and they tend to adopt "hot formulas" inappropriately. This paper introduces four real-life examples for bridging five principles, from fluids to thermodynamics, including (1) buoyant force, (2) thermal expansion, (3) the ideal-gas law, (4) the 1st law,…

  12. UPDATE ON THE INTERNATIONAL EXPERIMENT ON CO2 OCEAN SEQUESTRATION

    E-print Network

    quantities of CO2 is uncertain. The deep ocean is one of only a few possible CO2 disposal options (others discussed strategies for ocean carbon sequestration are direct injection of CO2 into the deep ocean and iron in the deep ocean, forming a buoyant plume. Sea water will be entrained into the rising droplet plume

  13. Heat Flux From the Endeavour Segment of the Juan de Fuca Ridge

    Microsoft Academic Search

    W. J. Thompson; R. E. McDuff; F. R. Stahr; D. R. Yoerger; M. Jakuba

    2005-01-01

    The very essence of a hydrothermal system is transfer of heat by a convecting fluid, yet the flux of heat remains a poorly known quantity. Past studies of heat flux consisted primarily of point measurements of temperature and fluid flow at individual vent sites and inventories of the neutrally buoyant plume above the field. In 2000 the Flow Mow project

  14. Repeat Hydrography at the Endeavour Integrated Study Site, 2004 - 2006

    Microsoft Academic Search

    J. P. Kellogg; R. E. McDuff; R. E. Thomson; F. R. Stahr

    2006-01-01

    Significant differences exist between hydrographic transects made in the summers from 2004 to 2006 at the Endeavour Segment Integrated Study Site on the Juan de Fuca Ridge. Along and across axis sections describe the hydrographic conditions above the segment in three dimensions. The resulting sections allow for rapid evaluation of the characteristics of the neutrally buoyant plume over each of

  15. 33 CFR 183.114 - Test of flotation materials.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...plus or minus 2 °C in a 5-percent solution of trisodium phosphate in water. (g) 30-day bilge cleaner test...plus or minus 2 °C in a 5-percent solution of trisodium phosphate in water. (h) The buoyant force...

  16. Determination of Bacterial Antibiotic Resistance Based on Osmotic Shock Response

    E-print Network

    Manalis, Scott

    Determination of Bacterial Antibiotic Resistance Based on Osmotic Shock Response Scott M. Knudsen. This behavior can be used to differentiate between an antibiotic-resistant and an antibiotic-susceptible strain- sion of the SMR for rapid detection of antibiotic resistance. The buoyant densities of bacterial cells

  17. Vortex generation by line plumes in a rotating stratied fluid

    Microsoft Academic Search

    J OHN; W. M. B USH; ANDREW W. W OODS

    1999-01-01

    We present the results of an experimental investigation of the generation of coherent vortical structures by buoyant line plumes in rotating fluids. Both uniform and stratied ambients are considered. By combining the scalings describing turbulent plumes and geostrophically balanced vortices, we develop a simple model which predicts the scale of the coherent vortical structures in excellent accord with laboratory experiments.

  18. RESEARCH ARTICLE Caldera resurgence during magma replenishment

    E-print Network

    /or erupted into each system; this magma is chemically distinct from rhyolite magma which was resident in each the system, it is able to heat, remobilize, and mingle with residual crystal-rich rhyolite remaining in the shallow mag- ma chamber. Dacite and remobilized rhyolite rise buoyantly to form laccoliths by lifting

  19. Lipid Rafts Prepared by Different Methods Contain Different Connexin Channels, but Gap Junctions Are Not Lipid Rafts

    E-print Network

    Harris, Andrew L.

    or to cold sodium carbonate extraction at high alkaline pH (5-7). Their buoyant density, due to their higher, 2005 ABSTRACT: Cell extraction with cold nonionic detergents or alkaline carbonate prepares by membrane insolubility in alkaline carbonate or different concentrations of Triton X100, Nonidet P40

  20. Trapping of low-index microparticles in an optical vortex

    E-print Network

    Swartzlander Jr., Grover A.

    momentum of a vortex may also be used to control the motion of other vortices.27,28 We recently reportedTrapping of low-index microparticles in an optical vortex K. T. Gahagan and G. A. Swartzlander, Jr in an optical-vortex trap was experimentally measured for two different systems: a buoyant hollow glass sphere