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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. Hydrostatic Modeling of Buoyant Plumes

    NASA Astrophysics Data System (ADS)

    Stroman, A.; Dewar, W. K.; Wienders, N.; Deremble, B.

    2014-12-01

    The Deepwater Horizon oil spill in the Gulf of Mexico has led to increased interest in understanding point source convection dynamics. Most of the existing oil plume models use a Lagrangian based approach, which computes integral measures such as plume centerline trajectory and plume radius. However, this approach doesn't account for feedbacks of the buoyant plume on the ambient environment. Instead, we employ an Eulerian based approach to acquire a better understanding of the dynamics of buoyant plumes. We have performed a series of hydrostatic modeling simulations using the MITgcm. Our results show that there is a dynamical response caused by the presence of the buoyant plume, in that there is a modification of the background flow. We find that the buoyant plume becomes baroclinically unstable and sheds eddies at the neutral buoyancy layer. We also explore different scenarios to determine the effect of the buoyancy source and the temperature stratification on the evolution of buoyant plumes.

  3. Drag of buoyant vortex rings

    NASA Astrophysics Data System (ADS)

    Vasel-Be-Hagh, Ahmadreza; Carriveau, Rupp; Ting, David S.-K.; Turner, John Stewart

    2015-10-01

    Extending from the model proposed by Vasel-Be-Hagh et al. [J. Fluid Mech. 769, 522 (2015), 10.1017/jfm.2015.126], a perturbation analysis is performed to modify Turner's radius by taking into account the viscous effect. The modified radius includes two terms; the zeroth-order solution representing the effect of buoyancy, and the first-order perturbation correction describing the influence of viscosity. The zeroth-order solution is explicit Turner's radius; the first-order perturbation modification, however, includes the drag coefficient, which is unknown and of interest. Fitting the photographically measured radius into the modified equation yields the time history of the drag coefficient of the corresponding buoyant vortex ring. To give further clarification, the proposed model is applied to calculate the drag coefficient of a buoyant vortex ring at a Bond number of approximately 85; a similar procedure can be applied at other Bond numbers.

  4. Buoyant jet behavior in confined regions

    E-print Network

    Fry, David J.

    1981-01-01

    Previous confined jet studies have emphasized the behavior of non-buoyant jets inside ducts or near plane boundaries (Coanda effect). Buoyancy, however, is a major factor in the confined jet behavior experienced in many ...

  5. 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.

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

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 6 2014-10-01 2014-10-01 false Capacity of buoyant apparatus. 160.010-6 Section 160.010-6 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Buoyant Apparatus for Merchant Vessels § 160.010-6 Capacity of buoyant apparatus. (a)...

  7. 46 CFR 131.870 - Life floats and buoyant apparatus.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Life floats and buoyant apparatus. 131.870 Section 131... OPERATIONS Markings for Fire Equipment and Emergency Equipment § 131.870 Life floats and buoyant apparatus. (a) The name of the vessel must be plainly marked or painted on each life float or buoyant...

  8. 46 CFR 131.870 - Life floats and buoyant apparatus.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Life floats and buoyant apparatus. 131.870 Section 131... OPERATIONS Markings for Fire Equipment and Emergency Equipment § 131.870 Life floats and buoyant apparatus. (a) The name of the vessel must be plainly marked or painted on each life float or buoyant...

  9. 46 CFR 131.870 - Life floats and buoyant apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Life floats and buoyant apparatus. 131.870 Section 131... OPERATIONS Markings for Fire Equipment and Emergency Equipment § 131.870 Life floats and buoyant apparatus. (a) The name of the vessel must be plainly marked or painted on each life float or buoyant...

  10. 46 CFR 131.870 - Life floats and buoyant apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Life floats and buoyant apparatus. 131.870 Section 131... OPERATIONS Markings for Fire Equipment and Emergency Equipment § 131.870 Life floats and buoyant apparatus. (a) The name of the vessel must be plainly marked or painted on each life float or buoyant...

  11. 46 CFR 131.870 - Life floats and buoyant apparatus.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Life floats and buoyant apparatus. 131.870 Section 131... OPERATIONS Markings for Fire Equipment and Emergency Equipment § 131.870 Life floats and buoyant apparatus. (a) The name of the vessel must be plainly marked or painted on each life float or buoyant...

  12. 46 CFR 160.010-6 - Capacity of buoyant apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 6 2010-10-01 2010-10-01 false Capacity of buoyant apparatus. 160.010-6 Section 160.010...-6 Capacity of buoyant apparatus. (a) The number of persons for which a buoyant apparatus is approved... apparatus is not considered in determining the capacity. (b)...

  13. 46 CFR 108.697 - Buoyant work vests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Buoyant work vests. 108.697 Section 108.697 Shipping... EQUIPMENT Miscellaneous Equipment § 108.697 Buoyant work vests. (a) Each buoyant work vest on a unit must be... work vests must be— (1) Used, stowed, and maintained in accordance with the procedures set out in...

  14. 46 CFR 108.697 - Buoyant work vests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Buoyant work vests. 108.697 Section 108.697 Shipping... EQUIPMENT Miscellaneous Equipment § 108.697 Buoyant work vests. (a) Each buoyant work vest on a unit must be... work vests must be— (1) Used, stowed, and maintained in accordance with the procedures set out in...

  15. 46 CFR 108.697 - Buoyant work vests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Buoyant work vests. 108.697 Section 108.697 Shipping... EQUIPMENT Miscellaneous Equipment § 108.697 Buoyant work vests. (a) Each buoyant work vest on a unit must be... work vests must be— (1) Used, stowed, and maintained in accordance with the procedures set out in...

  16. 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...

  17. 46 CFR 108.697 - Buoyant work vests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Buoyant work vests. 108.697 Section 108.697 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Miscellaneous Equipment § 108.697 Buoyant work vests. (a) Each buoyant work vest on a unit must be approved under Subpart 160.053 or...

  18. 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

  19. Two-link swimming using buoyant orientation

    NASA Astrophysics Data System (ADS)

    Burton, L. J.; Hatton, R. L.; Choset, H.; Hosoi, A. E.

    2010-09-01

    The scallop theorem posits that a two-link system immersed in a fluid at low Reynolds number cannot achieve any net translation via cyclic changes in its hinge angle. Here, we propose an approach to "breaking" this theorem, based on a static separation between the centers of mass and buoyancy in a net neutrally buoyant system. This separation gives the system a natural equilibrium orientation, allowing it to passively reorient without changing shape.

  20. Buoyant thermocapillary flows in a multilayer system

    NASA Astrophysics Data System (ADS)

    Simanovskii, Ilya B.; Viviani, Antonio; Legros, Jean-Claude

    2008-03-01

    The nonlinear buoyant-thermocapillary flows in a three-layer system, filling a closed cavity and subjected to a temperature gradient directed along the interfaces, are investigated. The nonlinear simulations of convective regimes are performed by the finite-difference method. It is found that for sufficiently large values of the Grashof number, the long vortices turn into multicell structures. To cite this article: I.B. Simanovskii et al., C. R. Mecanique 336 (2008).

  1. Generalizing the definition of buoyant force

    NASA Astrophysics Data System (ADS)

    Mungan, Carl

    2006-03-01

    I propose that buoyant force be defined as the negative of the weight of the displaced fluids, rather than as the net force exerted by fluid pressures on the surface of an object. In the case of a fully submerged object, these two definitions are equivalent. However, if the object makes contact with a solid surface (such as the bottom of a beaker of liquid), only the first definition is well-defined, while the second depends on the ambiguous issue of how much fluid penetrates between the object and the solid surface.

  2. 46 CFR 160.010-5 - Buoyant apparatus with plastic foam buoyancy.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

  3. 46 CFR 160.010-5 - Buoyant apparatus with plastic foam buoyancy.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 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...

  4. 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...

  5. 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...

  6. 46 CFR 160.010-5 - Buoyant apparatus with plastic foam buoyancy.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 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...

  7. 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.

  8. Experiments on a round turbulent buoyant plume

    NASA Technical Reports Server (NTRS)

    Shabbir, Aamir; George, William K.

    1992-01-01

    This paper reports a comprehensive set of hot-wire measurements of a round buoyant plume which was generated by forcing a jet of hot air vertically up into quiescent environment. The boundary conditions of the experiment were measured, and are documented in the present paper in an attempt to sort out the contradictory mean flow results from the earlier studies. The ambient temperature was monitored to insure that the facility was not stratified and that the experiment was conducted in a neutral environment. The axisymmetry of the flow was checked by using a planar array of sixteen thermocouples and the mean temperature measurements from these are used to supplement the hot-wire measurements. The source flow conditions were measured so as to ascertain the rate at which the buoyancy was added to the flow. The measurements conserve buoyancy within 10 percent. The results are used to carry out the balances of the mean energy and momentum differential equations. In the mean energy equation it is found that the vertical advection of the energy is primarily balanced by the radial turbulent transport. In the mean momentum equation the vertical advection of momentum and the buoyancy force balance the radial turbulent transport. The buoyancy force is the second largest term in this balance and is responsible for the wider (and higher) velocity profiles in plumes as compared to jets. Budgets of the temperature variance and turbulence kinetic energy are also carried out in which thermal and mechanical dissipation rates are obtained as the closing terms. Similarities and differences between the two balances are discussed. It is found that even though the direct affect of buoyancy on turbulence, as evidenced by the buoyancy production term, is substantial, most of the turbulence is produced by shear. This is in contrast to the mean velocity field where the affect of buoyancy force is quite strong. Therefore, it is concluded that in a buoyant plume the primary affect of buoyancy on turbulence is indirect, and enters through the mean velocity field (giving larger shear production).

  9. 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 ...

  10. A new framework for simulating forced homogeneous buoyant turbulent flows

    NASA Astrophysics Data System (ADS)

    Carroll, Phares L.; Blanquart, Guillaume

    2015-06-01

    This work proposes a new simulation methodology to study variable density turbulent buoyant flows. The mathematical framework, referred to as homogeneous buoyant turbulence, relies on a triply periodic domain and incorporates numerical forcing methods commonly used in simulation studies of homogeneous, isotropic flows. In order to separate the effects due to buoyancy from those due to large-scale gradients, the linear scalar forcing technique is used to maintain the scalar variance at a constant value. Two sources of kinetic energy production are considered in the momentum equation, namely shear via an isotropic forcing term and buoyancy via the gravity term. The simulation framework is designed such that the four dimensionless parameters of importance in buoyant mixing, namely the Reynolds, Richardson, Atwood, and Schmidt numbers, can be independently varied and controlled. The framework is used to interrogate fully non-buoyant, fully buoyant, and partially buoyant turbulent flows. The results show that the statistics of the scalar fields (mixture fraction and density) are not influenced by the energy production mechanism (shear vs. buoyancy). On the other hand, the velocity field exhibits anisotropy, namely a larger variance in the direction of gravity which is associated with a statistical dependence of the velocity component on the local fluid density.

  11. Arc Evolution in Response to the Subduction of Buoyant Features

    NASA Astrophysics Data System (ADS)

    Jenkins, Luke; Fourel, Loic; Goes, Saskia; Morra, Gabriele

    2015-04-01

    The subduction of buoyant features such as aseismic ridges or oceanic plateaux has been invoked to explain arc deformation, flat subduction and increase in seismic coupling. Other studies have challenged these ideas, attributing a larger role to the overriding plate. However, many open questions remain about the dynamics of the relative simple case of a single freely subducting plate. How big does a plateau need to be to change the arc shape? What is the control of plate's strength on the impact of buoyant features? How do the velocities adapt to the subduction of less dense material? In the present study, we propose a systematic approach in order to tackle these questions. We use a new 3-D coupled fluid-solid subduction model where the interaction between the slab and the isoviscous mantle is only calculated on the slab surface, significantly increasing computational efficiency. The oceanic plate rheology is visco-elasto-plastic and its top surface is free. We find that arc shape is significantly altered by the subduction of buoyant plateaux. Along the subduction plane through the plateau and depending on its size, the dip angle and the retreat velocity significantly decrease. Flat subduction is obtained in the case of large and strongly buoyant plateau/ridge. An interesting feature is that retreat velocity increases right after the plateau or ridge has finished subducting in order to catch up with the rest of the plate. The gradient in retreat velocity obtained along the trench may cause the slab to have a heterogeneous response to ridge push, eventually leading to slab advance where buoyant material is present. We apply our models to the Izu-Bonin-Marianas (IBM) trench and propose that subduction of the buoyant Caroline Island Ridge at the southern edge of the Mariana trench can explain both trench motion history and the current morphology of the IBM slab as imaged by seismic tomography.

  12. 46 CFR 160.010-5 - Buoyant apparatus with plastic foam buoyancy.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 6 2012-10-01 2012-10-01 false Buoyant apparatus with plastic foam buoyancy. 160.010-5... Vessels § 160.010-5 Buoyant apparatus with plastic foam buoyancy. (a) Buoyant apparatus with plastic foam buoyancy must have a plastic foam body with an external protective covering. The body may be reinforced...

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

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 6 2013-10-01 2013-10-01 false Buoyant apparatus with plastic foam buoyancy. 160.010-5... Vessels § 160.010-5 Buoyant apparatus with plastic foam buoyancy. (a) Buoyant apparatus with plastic foam buoyancy must have a plastic foam body with an external protective covering. The body may be reinforced...

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

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 6 2014-10-01 2014-10-01 false Buoyant apparatus with plastic foam buoyancy. 160.010-5 Section 160.010-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Buoyant Apparatus for Merchant Vessels § 160.010-5 Buoyant apparatus...

  15. 46 CFR 117.137 - Stowage of life floats and buoyant apparatus.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Stowage of life floats and buoyant apparatus. 117.137... EQUIPMENT AND ARRANGEMENTS Survival Craft Arrangements and Equipment § 117.137 Stowage of life floats and buoyant apparatus. (a) In addition to meeting § 117.130, each life float and buoyant apparatus must...

  16. 46 CFR 160.010-5 - Buoyant apparatus with plastic foam buoyancy.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 6 2011-10-01 2011-10-01 false Buoyant apparatus with plastic foam buoyancy. 160.010-5... Vessels § 160.010-5 Buoyant apparatus with plastic foam buoyancy. (a) Buoyant apparatus with plastic foam buoyancy must have a plastic foam body with an external protective covering. The body may be reinforced...

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

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 6 2010-10-01 2010-10-01 false Buoyant apparatus with plastic foam buoyancy. 160.010-5... Vessels § 160.010-5 Buoyant apparatus with plastic foam buoyancy. (a) Buoyant apparatus with plastic foam buoyancy must have a plastic foam body with an external protective covering. The body may be reinforced...

  18. 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...

  19. 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…

  20. 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.

  1. Density Driven Removal of Sediment from a Buoyant Muddy Plume

    NASA Astrophysics Data System (ADS)

    Rouhnia, M.; Strom, K.

    2014-12-01

    Experiments were conducted to study the effect of settling driven instabilities on sediment removal from hypopycnal plumes. Traditional approaches scale removal rates with particle settling velocity however, it has been suggested that the removal from buoyant suspensions happens at higher rates. The enhancement of removal is likely due to gravitational instabilities, such as fingering, at two-fluid interface. Previous studies have all sought to suppress flocculation, and no simple model exists to predict the removal rates under the effect of such instabilities. This study examines whether or not flocculation hampers instability formation and presents a simple removal rate model accounting for gravitational instabilities. A buoyant suspension of flocculated Kaolinite overlying a base of clear saltwater was investigated in a laboratory tank. Concentration was continuously measured in both layers with a pair of OBS sensors, and interface was monitored with digital cameras. Snapshots from the video were used to measure finger velocity. Samples of flocculated particles at the interface were extracted to retrieve floc size data using a floc camera. Flocculation did not stop creation of settling-driven fingers. A simple cylinder-based force balance model was capable of predicting finger velocity. Analogy of fingering process of fine grained suspensions to thermal plume formation and the concept of Grashof number enabled us to model finger spacing as a function of initial concentration. Finally, from geometry, the effective cross-sectional area was correlated to finger spacing. Reformulating the outward flux expression was done by substitution of finger velocity, rather than particle settling velocity, and finger area instead of total area. A box model along with the proposed outward flux was used to predict the SSC in buoyant layer. The model quantifies removal flux based on the initial SSC and is in good agreement with the experimental data.

  2. Buoyant triacylglycerol-filled green algae and methods therefor

    DOEpatents

    Goodenough, Ursula; Goodson, Carrie

    2015-04-14

    Cultures of Chlamydomonas are disclosed comprising greater than 340 mg/l triacylglycerols (TAG). The cultures can include buoyant Chlamydomonas. Methods of forming the cultures are also disclosed. In some embodiments, these methods comprise providing Chlamydomonas growing in log phase in a first culture medium comprising a nitrogen source and acetate, replacing the first culture medium with a second medium comprising acetate but no nitrogen source, and subsequently supplementing the second medium with additional acetate. In some embodiments, a culture can comprise at least 1,300 mg/l triacyglycerols. In some embodiments, cultures can be used to produce a biofuel such as biodiesel.

  3. The effects of Venus' thermal structure on buoyant magma ascent

    NASA Technical Reports Server (NTRS)

    Sakimoto, S. E. H.; Zuber, M. T.

    1992-01-01

    The recent Magellan images have revealed a broad spatial distribution of surface volcanism on Venus. Previous work in modeling the ascent of magma on both Venus and Earth has indicated that the planetary thermal structure significantly influences the magmatic cooling rates and thus the amount of magma that can be transported to the surface before solidification. In order to understand which aspects of the thermal structure have the greatest influence on the cooling of ascending magma, we have constructed magma cooling curves for both plutonic and crack buoyant ascent mechanisms, and evaluated the curves for variations in the planetary mantle temperature, thermal gradient curvature with depth, surface temperature gradient, and surface temperature. The planetary thermal structure is modeled as T/T(sub 0) = 1-tau(1-Z/Z(sub 0)(exp n), where T is the temperature, T(sub 0) is the source depth temperature, tau = 1-(T(sub s)/T(sub 0)) where T(sub s) is the planetary surface temperature, Z is the depth, Z(sub 0) is the source depth, and n is a constant that controls thermal gradient curvature with depth. The equation is used both for mathematical convenience and flexibility, as well as its fit to the thermal gradients predicted by the cooling half-space models. We assume a constant velocity buoyant ascent, body-averaged magma temperatures and properties, an initially crystal-free magma, and the same liquidus and solidus for both Venus and Earth.

  4. A Model for Temperature Fluctuations in a Buoyant Plume

    NASA Astrophysics Data System (ADS)

    Bisignano, A.; Devenish, B. J.

    2015-11-01

    We present a hybrid Lagrangian stochastic model for buoyant plume rise from an isolated source that includes the effects of temperature fluctuations. The model is based on that of Webster and Thomson (Atmos Environ 36:5031-5042, 2002) in that it is a coupling of a classical plume model in a crossflow with stochastic differential equations for the vertical velocity and temperature (which are themselves coupled). The novelty lies in the addition of the latter stochastic differential equation. Parametrizations of the plume turbulence are presented that are used as inputs to the model. The root-mean-square temperature is assumed to be proportional to the difference between the centreline temperature of the plume and the ambient temperature. The constant of proportionality is tuned by comparison with equivalent statistics from large-eddy simulations (LES) of buoyant plumes in a uniform crossflow and linear stratification. We compare plume trajectories for a wide range of crossflow velocities and find that the model generally compares well with the equivalent LES results particularly when added mass is included in the model. The exception occurs when the crossflow velocity component becomes very small. Comparison of the scalar concentration, both in terms of the height of the maximum concentration and its vertical spread, shows similar behaviour. The model is extended to allow for realistic profiles of ambient wind and temperature and the results are compared with LES of the plume that emanated from the explosion and fire at the Buncefield oil depot in 2005.

  5. 46 CFR 131.580 - Servicing of inflatable liferafts, inflatable lifejackets, inflatable buoyant apparatus, and...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...) No later than the month and year on its servicing sticker affixed under 46 CFR 160.151-57(n), except... lifejackets, inflatable buoyant apparatus, and inflated rescue boats. 131.580 Section 131.580 Shipping COAST..., and inflated rescue boats. (a) An inflatable liferaft or inflatable buoyant apparatus must be...

  6. 46 CFR 131.580 - Servicing of inflatable liferafts, inflatable lifejackets, inflatable buoyant apparatus, and...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) No later than the month and year on its servicing sticker affixed under 46 CFR 160.151-57(n), except... lifejackets, inflatable buoyant apparatus, and inflated rescue boats. 131.580 Section 131.580 Shipping COAST..., and inflated rescue boats. (a) An inflatable liferaft or inflatable buoyant apparatus must be...

  7. 46 CFR 131.580 - Servicing of inflatable liferafts, inflatable lifejackets, inflatable buoyant apparatus, and...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...) No later than the month and year on its servicing sticker affixed under 46 CFR 160.151-57(n), except... lifejackets, inflatable buoyant apparatus, and inflated rescue boats. 131.580 Section 131.580 Shipping COAST..., and inflated rescue boats. (a) An inflatable liferaft or inflatable buoyant apparatus must be...

  8. 46 CFR 131.580 - Servicing of inflatable liferafts, inflatable lifejackets, inflatable buoyant apparatus, and...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) No later than the month and year on its servicing sticker affixed under 46 CFR 160.151-57(n), except... lifejackets, inflatable buoyant apparatus, and inflated rescue boats. 131.580 Section 131.580 Shipping COAST..., and inflated rescue boats. (a) An inflatable liferaft or inflatable buoyant apparatus must be...

  9. 46 CFR 131.580 - Servicing of inflatable liferafts, inflatable lifejackets, inflatable buoyant apparatus, and...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) No later than the month and year on its servicing sticker affixed under 46 CFR 160.151-57(n), except... lifejackets, inflatable buoyant apparatus, and inflated rescue boats. 131.580 Section 131.580 Shipping COAST..., and inflated rescue boats. (a) An inflatable liferaft or inflatable buoyant apparatus must be...

  10. Buoyant convection from a discrete source in a leaky porous medium

    E-print Network

    Flynn, Morris R.

    Buoyant convection from a discrete source in a leaky porous medium M.A. Roes1, M.R. Flynn1,2 and D sequestration option, CO2 dissolution into the brine must occur before the buoyant plume of sc-CO2 has this question depends very much on the integrity of the formation cap-rock; however, fluid mechanical

  11. 46 CFR 160.010-4 - General requirements for buoyant apparatus.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 6 2014-10-01 2014-10-01 false General requirements for buoyant apparatus. 160.010-4 Section 160.010-4 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Buoyant Apparatus for Merchant Vessels § 160.010-4 General requirements...

  12. 46 CFR 180.137 - Stowage of life floats and buoyant apparatus.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Stowage of life floats and buoyant apparatus. 180.137... § 180.137 Stowage of life floats and buoyant apparatus. (a) In addition to meeting § 180.130, each life... other standard specified by the Commandant; (2) Of proper strength for the size of the life float...

  13. Buoyant surface jet analysis of the Yukon River

    NASA Technical Reports Server (NTRS)

    Gosink, J. P.

    1988-01-01

    Thermal infrared satellite imagery of the discharge from the Yukon River obtained on July 5, 1985 was compared with hydraulic theory for the dilution of buoyant surface jets. In a crossflow, the theory predicts that the plume will follow an x exp 1/3 trajectory where x is distance alongshore, and that the plume temperature will decay according to x exp - 1/6 due to mixing with the receiving water. Measurements of the Yukon River discharge indicate very good agreement with the predicted trajectory, and less, but acceptable, agreement with the predicted dilution. Large scale thermal fronts are also observable in the thermal imagery; the fronts may be associated with excursions of the plume due to tidal currents.

  14. 46 CFR 160.010-4 - General requirements for buoyant apparatus.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... light twine. (h) Each peripheral body type buoyant apparatus without a net or platform on the inside... pigmented in a dark color. A typical method of securing lifelines and pendants to straps of webbing is...

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

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... light twine. (h) Each peripheral body type buoyant apparatus without a net or platform on the inside... pigmented in a dark color. A typical method of securing lifelines and pendants to straps of webbing is...

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

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... light twine. (h) Each peripheral body type buoyant apparatus without a net or platform on the inside... pigmented in a dark color. A typical method of securing lifelines and pendants to straps of webbing is...

  17. 46 CFR 160.010-4 - General requirements for buoyant apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... light twine. (h) Each peripheral body type buoyant apparatus without a net or platform on the inside... pigmented in a dark color. A typical method of securing lifelines and pendants to straps of webbing is...

  18. 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.

  19. Residence time of buoyant objects in drowning machines

    PubMed Central

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

    2011-01-01

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

  20. Role of buoyant flame dynamics in wildfire spread.

    PubMed

    Finney, Mark A; Cohen, Jack D; Forthofer, Jason M; McAllister, Sara S; Gollner, Michael J; Gorham, Daniel J; Saito, Kozo; Akafuah, Nelson K; Adam, Brittany A; English, Justin D

    2015-08-11

    Large wildfires of increasing frequency and severity threaten local populations and natural resources and contribute carbon emissions into the earth-climate system. Although wildfires have been researched and modeled for decades, no verifiable physical theory of spread is available to form the basis for the precise predictions needed to manage fires more effectively and reduce their environmental, economic, ecological, and climate impacts. Here, we report new experiments conducted at multiple scales that appear to reveal how wildfire spread derives from the tight coupling between flame dynamics induced by buoyancy and fine-particle response to convection. Convective cooling of the fine-sized fuel particles in wildland vegetation is observed to efficiently offset heating by thermal radiation until convective heating by contact with flames and hot gasses occurs. The structure and intermittency of flames that ignite fuel particles were found to correlate with instabilities induced by the strong buoyancy of the flame zone itself. Discovery that ignition in wildfires is critically dependent on nonsteady flame convection governed by buoyant and inertial interaction advances both theory and the physical basis for practical modeling. PMID:26183227

  1. Experimental and computational investigation of underwater buoyant oil jets

    NASA Astrophysics Data System (ADS)

    Berard, Leandre; Raessi, Mehdi; Bauer, Michael; Friedman, Peter; Codyer, Stephen; University of Massachusetts Dartmouth Team

    2013-11-01

    We present experimental and numerical results on the breakup of underwater positively buoyant oil jets at a wide range of Reynolds, Weber and Richardson numbers and several viscosity ratios. Three main jet breakup regimes are observed: atomization, skirt-type and pinch-off. A threshold Weber number for the atomization regime is found to be around 100, varying slightly with the jet Eötvös number. The Ohnesorge-Reynolds correlation proposed by Masutani and Adams as the boundary for the atomization regime is shown to be applicable to our broader data set as well. Results suggest that the breakup of a positive buoyancy-driven jet occurs only when the jet is accelerated to a point where the local Richardson number becomes less than 0.4, in which case the local Weber number is above 10. The numerical results reveal the mechanisms leading to formation of small droplets around the perimeter of energetic jets and umbrella-shaped jet separations at less energetic cases. The time-averaged lateral expansion of the simulated jets, representing four different conditions, are presented as a function of the height along the jet.

  2. A numerical study of interacting buoyant cooling-tower plumes

    NASA Astrophysics Data System (ADS)

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

    The compact design of mechanical cooling towers necessitates that the plumes are issued into the cross-wind in close proximity. An improved understanding of the interaction of adjacent plumes is therefore required for better design of such cooling towers, which may lead to a reduction in their environmental impact. This paper presents the results of a numerical investigation into the interaction of two adjacent plumes in a cross-flow. The numerical model simulates small-scale wind tunnel experiments of a cooling tower arrangement. The computations are performed for three-dimensional, turbulent, buoyant and interacting plumes, and for a single plume for comparison. Two double-source arrangements, namely, tandem and side-by-side, with respect to the oncoming atmospheric boundary layer are considered. A low Reynolds number k- ? turbulence model is used with two discretisation schemes, hybrid and QUICK, and the results are compared. Comparisons are also made with the experimental results. The results show that the interaction of side-by-side plumes is dominated by the interaction of the rotating vortex pairs within the plumes. A tandem source arrangement leads to early merging and efficient rise enhancement. Comparisons of the predicted results with experimental data show good agreement for the plume rise.

  3. Evolution of highly buoyant thermals in a stratified layer

    E-print Network

    Axel Brandenburg; John Hazlehurst

    2001-02-17

    The buoyant rise of thermals (i.e. bubbles of enhanced entropy, but initially in pressure equilibrium) is investigated numerically in three dimensions for the case of an adiabatically stratified layer covering 6-9 pressure scale heights. It is found that these bubbles can travel to large heights before being braked by the excess pressure that builds up in order to drive the gas sideways in the head of the bubble. Until this happens, the momentum of the bubble grows as described by the time-integrated buoyancy force. This validates the simple theory of bubble dynamics whereby the mass entrainment of the bubble provides an effective braking force well before the bubble stops ascending. This is quantified by an entrainment parameter alpha which is calculated from the simulations and is found to be in good agreement with the experimental measurements. This work is discussed in the context of contact binaries whose secondaries could be subject to dissipative heating in the outermost layers.

  4. Tension buoyant tower for small fields in deepwaters

    SciTech Connect

    Perryman, S.R.; Horton, E.E.; Halkyard, J.E.; Beynet, P.A.

    1995-12-31

    The paper describes a concept for a deepwater platform capable of supporting surface wellheads and drilling or workover operations and/or production equipment for up to 18 wells. The fundamental principles are described along with the functions of the key components. The previous analytical studies and model tests which have contributed to the concept are shown to confirm and clarify the concept. The concept could be applicable to hydrocarbon reservoirs in water depths from 1,500 ft to several thousand feet worldwide. The concept can be engineered, fabricated and installed using existing methods and infrastructure. Drilling operations are similar to jack-up drilling technology. The results show that by restraining the buoyant hull against heave, while permitting some amount of pitch, an economical system can be configured. A key factor is the arrangement of well and structural tubular axial stiffnesses in relation to their distance from the center. The concept allows mean and axial tensions to be optimized to the extent that nonpremium threaded connectors may be utilized for the tendons and run by the rig. 4 refs., 16 figs., 1 tab.

  5. Role of buoyant flame dynamics in wildfire spread

    PubMed Central

    Finney, Mark A.; Cohen, Jack D.; Forthofer, Jason M.; McAllister, Sara S.; Gollner, Michael J.; Gorham, Daniel J.; Saito, Kozo; Akafuah, Nelson K.; Adam, Brittany A.; English, Justin D.

    2015-01-01

    Large wildfires of increasing frequency and severity threaten local populations and natural resources and contribute carbon emissions into the earth-climate system. Although wildfires have been researched and modeled for decades, no verifiable physical theory of spread is available to form the basis for the precise predictions needed to manage fires more effectively and reduce their environmental, economic, ecological, and climate impacts. Here, we report new experiments conducted at multiple scales that appear to reveal how wildfire spread derives from the tight coupling between flame dynamics induced by buoyancy and fine-particle response to convection. Convective cooling of the fine-sized fuel particles in wildland vegetation is observed to efficiently offset heating by thermal radiation until convective heating by contact with flames and hot gasses occurs. The structure and intermittency of flames that ignite fuel particles were found to correlate with instabilities induced by the strong buoyancy of the flame zone itself. Discovery that ignition in wildfires is critically dependent on nonsteady flame convection governed by buoyant and inertial interaction advances both theory and the physical basis for practical modeling. PMID:26183227

  6. Physical and Numerical Modeling of Buoyant Groundwater Plumes

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

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

  7. 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.

  8. Acoustic imaging, visualization, and quantification of buoyant hydrothermal plumes in the Ocean

    NASA Astrophysics Data System (ADS)

    Rona, P. A.; Bemis, K. G.; Silver, D.; Jones, C. D.

    We develop and apply visualization and quantification methods to reconstruct hydrothermal plumes in 3D from acoustic images and to make the first direct measurements from the reconstructions of scalar properties that describe the behavior of two buoyant plumes discharging from adjacent black smoker chimneys. The actual behavior is then compared to that predicted by a classic simple buoyant plume model. The images are reconstructed as isointensity surfaces of backscatter from particulate matter suspended in the plumes. The measurements pertinent to the role of the plumes as agents of dispersal of heat and mass into the ocean include change with height of diameter, particle distribution, dilution, centerline attitude, surface protrusions, and connectivity. The protrusions are the surface expression of eddies and appear to follow a bifurcating helical flow pattern that resemble simulation of the naturally forced flow of coherent vortex rings as the eddies rise with the buoyant plume. These direct measurements and the derived entrainment coefficient are generally consistent with behavior predicted by the simple buoyant plume model and support engulfment by vortex shedding as a primary mechanism for entrainment of surrounding seawater. Deviations from predicted buoyant plume behavior are diagnostic of particle dynamics.

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

    PubMed

    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. PMID:25554341

  10. 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.

  11. 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.

  12. 46 CFR 185.730 - Servicing of inflatable liferafts, inflatable buoyant apparatus, inflatable life jackets, and...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... servicing sticker affixed under 46 CFR 160.151-57(n), except that servicing may be delayed until the next... apparatus, inflatable life jackets, and inflated rescue boats. 185.730 Section 185.730 Shipping COAST GUARD... liferafts, inflatable buoyant apparatus, inflatable life jackets, and inflated rescue boats. (a)...

  13. 46 CFR 185.730 - Servicing of inflatable liferafts, inflatable buoyant apparatus, inflatable life jackets, and...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... servicing sticker affixed under 46 CFR 160.151-57(n), except that servicing may be delayed until the next... apparatus, inflatable life jackets, and inflated rescue boats. 185.730 Section 185.730 Shipping COAST GUARD... liferafts, inflatable buoyant apparatus, inflatable life jackets, and inflated rescue boats. (a)...

  14. 46 CFR 185.730 - Servicing of inflatable liferafts, inflatable buoyant apparatus, inflatable life jackets, and...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... servicing sticker affixed under 46 CFR 160.151-57(n), except that servicing may be delayed until the next... apparatus, inflatable life jackets, and inflated rescue boats. 185.730 Section 185.730 Shipping COAST GUARD... liferafts, inflatable buoyant apparatus, inflatable life jackets, and inflated rescue boats. (a)...

  15. 46 CFR 185.730 - Servicing of inflatable liferafts, inflatable buoyant apparatus, inflatable life jackets, and...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... servicing sticker affixed under 46 CFR 160.151-57(n), except that servicing may be delayed until the next... apparatus, inflatable life jackets, and inflated rescue boats. 185.730 Section 185.730 Shipping COAST GUARD... liferafts, inflatable buoyant apparatus, inflatable life jackets, and inflated rescue boats. (a)...

  16. 46 CFR 185.730 - Servicing of inflatable liferafts, inflatable buoyant apparatus, inflatable life jackets, and...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... servicing sticker affixed under 46 CFR 160.151-57(n), except that servicing may be delayed until the next... apparatus, inflatable life jackets, and inflated rescue boats. 185.730 Section 185.730 Shipping COAST GUARD... liferafts, inflatable buoyant apparatus, inflatable life jackets, and inflated rescue boats. (a)...

  17. 46 CFR 160.010-4 - General requirements for buoyant apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...and the hank secured by not more than two turns of light twine. (h) Each peripheral body type buoyant apparatus...unless it is of a type represented by its manufacturer as ultraviolet light resistant, or it is pigmented in a dark...

  18. 46 CFR 160.010-4 - General requirements for buoyant apparatus.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...and the hank secured by not more than two turns of light twine. (h) Each peripheral body type buoyant apparatus...unless it is of a type represented by its manufacturer as ultraviolet light resistant, or it is pigmented in a dark...

  19. 46 CFR 160.010-4 - General requirements for buoyant apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...and the hank secured by not more than two turns of light twine. (h) Each peripheral body type buoyant apparatus...unless it is of a type represented by its manufacturer as ultraviolet light resistant, or it is pigmented in a dark...

  20. 46 CFR 160.010-4 - General requirements for buoyant apparatus.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...and the hank secured by not more than two turns of light twine. (h) Each peripheral body type buoyant apparatus...unless it is of a type represented by its manufacturer as ultraviolet light resistant, or it is pigmented in a dark...

  1. 46 CFR 160.010-4 - General requirements for buoyant apparatus.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...and the hank secured by not more than two turns of light twine. (h) Each peripheral body type buoyant apparatus...unless it is of a type represented by its manufacturer as ultraviolet light resistant, or it is pigmented in a dark...

  2. Effect of Technology Enhanced Conceptual Change Texts on Students' Understanding of Buoyant Force

    ERIC Educational Resources Information Center

    Ozkan, Gulbin; Selcuk, Gamze Sezgin

    2015-01-01

    In this study, the effect of technology enhanced conceptual change texts on elementary school students' understanding of buoyant force was investigated. The conceptual change texts (written forms) used in this study are proven for effectiveness and are enriched by using technology support in this study. These texts were tried out on two groups. A…

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

    E-print Network

    Hickey, Barbara

    Influence of a buoyant river plume on phytoplankton nutrient dynamics: What controls standing of these stations, nutrient (nitrate, ammonium, and ammonium inhibition of nitrate) kinetics were obtained, as well were there any symptoms of iron limitation in the short term. We conclude that phytoplankton

  4. 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...

  5. 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...

  6. A study of the accuracy of neutrally buoyant bubbles used as flow tracers in air

    NASA Technical Reports Server (NTRS)

    Kerho, Michael F.

    1993-01-01

    Research has been performed to determine the accuracy of neutrally buoyant and near neutrally buoyant bubbles used as flow tracers in air. Theoretical, computational, and experimental results are presented to evaluate the dynamics of bubble trajectories and factors affecting their ability to trace flow-field streamlines. The equation of motion for a single bubble was obtained and evaluated using a computational scheme to determine the factors which affect a bubble's trajectory. A two-dimensional experiment was also conducted to experimentally determine bubble trajectories in the stagnation region of NACA 0012 airfoil at 0 deg angle of attack using a commercially available helium bubble generation system. Physical properties of the experimental bubble trajectories were estimated using the computational scheme. These properties included the density ratio and diameter of the individual bubbles. the helium bubble system was then used to visualize and document the flow field about a 30 deg swept semispan wing with simulated glaze ice. Results were compared to Navier-Stokes calculations and surface oil flow visualization. The theoretical and computational analysis have shown that neutrally buoyant bubbles will trace even the most complex flow patterns. Experimental analysis revealed that the use of bubbles to trace flow patterns should be limited to qualitative measurements unless care is taken to ensure neutral buoyancy. This is due to the difficulty in the production of neutrally buoyant bubbles.

  7. 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.

  8. The influence of shelfbreak forcing on the alongshelf penetration of the Danube buoyant water, Black sea

    NASA Astrophysics Data System (ADS)

    Yankovsky, Alexander E.; Lemeshko, Evgeny M.; Ilyin, Yuriy P.

    2004-06-01

    The buoyancy-driven coastal current propagating along the western coast in the Black Sea is forced by the discharge of several major European rivers including the Danube, Dnepr and South Bug. In this study, we present observational evidence that the buoyant water alongshelf penetration is strongly affected by shelfbreak mesoscale features associated with the Rim Current dynamics. The Rim Current is a major element of the Black Sea general circulation, typically following isobaths over the upper-to-middle slope. Two hydrographic surveys conducted in 1992 and 1994 have been chosen among available archive data for the detailed analysis. In both years, though Danube buoyant discharge was similar prior to the beginning of shipboard observations (varying around 7000 m 3 s -1), the buoyant water exhibited very different downstream (that is, in the direction of Kelvin wave) penetration. In 1992, it spread all the way around the southwestern corner of the Black Sea basin and then further eastward past the Bosporus Strait. In contrast, its downstream penetration was blocked in 1994 and buoyant water did not even reach Cape Kaliakra on the Bulgarian coast. This difference was related to the shelfbreak processes. In 1992, the cyclonic meander of the Rim Current merged with the coastal buoyant water thus promoting its advection from Cape Kaliakra downstream. In 1994, a strong anticyclone in the southwestern corner of the Black Sea completely blocked the propagation of a buoyancy-driven current past Cape Kaliakra. In addition, another anticyclone in the northwestern part of the sea advected buoyant water offshore to the central area of the northwestern shelf. The positions of anticyclonic eddies during a period of observations was confirmed by remote sensing data. As these and other examples indicate, coastal buoyancy driven currents can be effectively blocked and dispersed offshore by the shelfbreak anticyclones if the shelf width allows their interaction with buoyant water. Previous observational studies suggested an upwelling-favorable wind as the principal forcing agent that arrested downstream penetration of buoyancy-driven coastal currents.

  9. Smoke-Point Properties of Non-Buoyant Round Laminar Jet Diffusion Flames. Appendix J

    NASA Technical Reports Server (NTRS)

    Urban, D. L.; Yuan, Z.-G.; Sunderland, P. B.; Lin, K.-C.; Dai, Z.; Faeth, G. M.

    2000-01-01

    The laminar smoke-point properties of non-buoyant round laminar jet diffusion flames were studied emphasizing results from long-duration (100-230 s) experiments at microgravity carried out in orbit aboard the space shuttle Columbia. Experimental conditions included ethylene- and propane-fueled flames burning in still air at an ambient temperature of 300 K, pressures of 35-130 kPa, jet exit diameters of 1.6 and 2.7 mm, jet exit velocities of 170-690 mm/s, jet exit Reynolds numbers of 46-172, characteristic flame residence times of 40-302 ms, and luminous flame lengths of 15-63 mm. Contrary to the normal-gravity laminar smoke point, in microgravity, the onset of laminar smoke-point conditions involved two flame configurations: closed-tip flames with soot emissions along the flame axis and open-tip flames with soot emissions from an annular ring about the flame axis. Open-tip flames were observed at large characteristic flame residence times with the onset of soot emissions associated with radiative quenching near the flame tip: nevertheless, unified correlations of laminar smoke-point properties were obtained that included both flame configurations. Flame lengths at laminar smoke-point conditions were well correlated in terms of a corrected fuel flow rate suggested by a simplified analysis of flame shape. The present steady and non-buoyant flames emitted soot more readily than non-buoyant flames in earlier tests using ground-based microgravity facilities and than buoyant flames at normal gravity, as a result of reduced effects of unsteadiness, flame disturbances, and buoyant motion. For example, present measurements of laminar smoke-point flame lengths at comparable conditions were up to 2.3 times shorter than ground-based microgravity measurements and up to 6.4 times shorter than buoyant flame measurements. Finally, present laminar smoke-point flame lengths were roughly inversely proportional to pressure to a degree that is a somewhat smaller than observed during earlier tests both at microgravity (using ground-based facilities) and at normal gravity.

  10. Wake-Driven Dynamics of Finite-Sized Buoyant Spheres in Turbulence

    NASA Astrophysics Data System (ADS)

    Mathai, Varghese; Prakash, Vivek N.; Brons, Jon; Sun, Chao; Lohse, Detlef

    2015-09-01

    Particles suspended in turbulent flows are affected by the turbulence and at the same time act back on the flow. The resulting coupling can give rise to rich variability in their dynamics. Here we report experimental results from an investigation of finite-sized buoyant spheres in turbulence. We find that even a marginal reduction in the particle's density from that of the fluid can result in strong modification of its dynamics. In contrast to classical spatial filtering arguments and predictions of particle models, we find that the particle acceleration variance increases with size. We trace this reversed trend back to the growing contribution from wake-induced forces, unaccounted for in current particle models in turbulence. Our findings highlight the need for improved multiphysics based models that account for particle wake effects for a faithful representation of buoyant-sphere dynamics in turbulence.

  11. Wake-Driven Dynamics of Finite-Sized Buoyant Spheres in Turbulence.

    PubMed

    Mathai, Varghese; Prakash, Vivek N; Brons, Jon; Sun, Chao; Lohse, Detlef

    2015-09-18

    Particles suspended in turbulent flows are affected by the turbulence and at the same time act back on the flow. The resulting coupling can give rise to rich variability in their dynamics. Here we report experimental results from an investigation of finite-sized buoyant spheres in turbulence. We find that even a marginal reduction in the particle's density from that of the fluid can result in strong modification of its dynamics. In contrast to classical spatial filtering arguments and predictions of particle models, we find that the particle acceleration variance increases with size. We trace this reversed trend back to the growing contribution from wake-induced forces, unaccounted for in current particle models in turbulence. Our findings highlight the need for improved multiphysics based models that account for particle wake effects for a faithful representation of buoyant-sphere dynamics in turbulence. PMID:26430995

  12. 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.

  13. Evidence for osmoregulation of cell growth and buoyant density in Escherichia coli

    SciTech Connect

    Baldwin, W.W.; Kubitschek, H.E.

    1984-07-01

    The buoyant density of cells of Escherichia coli B/r NC32 increased with the osmolarity of the growth medium. Growth rate and its variability were also dependent upon the osmolarity of the medium. Maximum growth rates and minimum variability of these rates were obtained in Luria broth by addition of NaCl to a concentration of about 0.23 M. 6 references, 1 figure, 1 table.

  14. Impact of thermally induced buoyant flow on contaminant transport in homogeneous and layered systems

    NASA Astrophysics Data System (ADS)

    Krol, M. M.; Johnson, R.; Zhang, D.; Sleep, B. E.

    2012-12-01

    Electrical resistance heating (ERH) is currently the most widely used thermal remediation technology in the United States (U.S. EPA, In situ thermal treatment site profiles database). Typically, ERH is operated at or above boiling point temperatures to ensure complete volatilization of subsurface contaminants. However, heating sites to these temperatures requires both high power requirements and off-gas collection systems, and therefore high operational costs. As such, operating ERH at lower temperatures to take advantage of buoyancy effects on flow and transport has been proposed as a sustainable alternative. In this study, buoyant flow associated with thermal remediation was investigated using a two dimensional electro-thermal model. The model incorporated electrical current flow associated with resistance heating, energy and mass transport, and density dependent water flow. The model was used to simulate heating for sixteen subsurface scenarios, in which the applied groundwater flux and soil permeability were varied. The effects on contaminant transport were investigated using dimensionless numbers. Consistent with other studies, the model predicted the development of buoyant flow when the ratio between the Rayleigh and thermal Peclet numbers (buoyancy ratio) was greater than 1. Subsequently, the modeled scenarios were grouped into three categories based on the occurrence of buoyant flow and its effect on contaminant transport. The effect of buoyant flow on contaminant transport was largely dependent on the Rayleigh number. The impact of low permeability layers on heat and mass transport was also investigated by simulating layered systems with different electrode placements. In this case, higher temperatures developed in the low permeability layers due to their greater electrical conductivity. In addition, heating under low permeability layers led to stagnation zones and mass accumulation, while heating above the layers led to lower subsurface concentrations. Thus, the model provides insights into ERH design that can be used to optimize this technology.

  15. 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.

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

    SciTech Connect

    Nelson, Nicholas J.; Toomre, Juri; Brown, Benjamin P.; Brun, Allan Sacha

    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.

  17. Influence of Buoyant Convection on the Stability of Enclosed Laminar Flames

    NASA Technical Reports Server (NTRS)

    Brooker, John E.; Jia, Kezhong; Stocker, Dennis P.; Chen. Lea-Der

    1999-01-01

    Enclosed diffusion flames are commonly found in practical combustion systems, such as the power-plant combustor, gas turbine combustor, and jet engine after-burner. In these systems, fuel is injected into a duct with a co-flowing or cross-flowing air stream. In combustors, this flame is anchored at the burner (i.e., fuel jet inlet) unless adverse conditions cause the flame to lift off or blow out. Investigations of burner stability study the lift off, reattachment, and blow out of the flame. There have been numerous studies of flame stability. Relatively few studies have investigated the stability of flames with an oxidizer co-flow, compared with the number of studies on (nearly) free jet diffusion flames. The air flow around the fuel jet can significantly alter the lift off, reattachment and blow out of the jet diffusion flame. In normal gravity, however, the effects of the air flow on flame stability are often complicated by the presence of buoyant convection. A comparison of normal-gravity and microgravity flames can provide clear indication of the influence of forced and buoyant flows on the flame stability. The overall goal of the Enclosed Laminar Flames (ELF) research, described at the following URL site: http://zeta.lerc.nasa.gov/expr/elf.htm, is to improve our understanding of the effects of buoyant convection on the structure and stability of co-flow diffusion flames.

  18. Early-stage hypogene karstification in a mountain hydrologic system: A coupled thermohydrochemical model incorporating buoyant convection

    NASA Astrophysics Data System (ADS)

    Chaudhuri, A.; Rajaram, H.; Viswanathan, H.

    2013-09-01

    The early stage of hypogene karstification is investigated using a coupled thermohydrochemical model of a mountain hydrologic system, in which water enters along a water table and descends to significant depth (˜1 km) before ascending through a central high-permeability fracture. The model incorporates reactive alteration driven by dissolution/precipitation of limestone in a carbonic acid system, due to both temperature- and pressure-dependent solubility, and kinetics. Simulations were carried out for homogeneous and heterogeneous initial fracture aperture fields, using the FEHM (Finite Element Heat and Mass Transfer) code. Initially, retrograde solubility is the dominant mechanism of fracture aperture growth. As the fracture transmissivity increases, a critical Rayleigh number value is exceeded at some stage. Buoyant convection is then initiated and controls the evolution of the system thereafter. For an initially homogeneous fracture aperture field, deep well-organized buoyant convection rolls form. For initially heterogeneous aperture fields, preferential flow suppresses large buoyant convection rolls, although a large number of smaller rolls form. Even after the onset of buoyant convection, dissolution in the fracture is sustained along upward flow paths by retrograde solubility and by additional "mixing corrosion" effects closer to the surface. Aperture growth patterns in the fracture are very different from those observed in simulations of epigenic karst systems, and retain imprints of both buoyant convection and preferential flow. Both retrograde solubility and buoyant convection contribute to these differences. The paper demonstrates the potential value of coupled models as tools for understanding the evolution and behavior of hypogene karst systems.

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

    NASA Astrophysics Data System (ADS)

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

    2008-04-01

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

  20. Modified INPUFF model for studying the air dispersion of neutrally buoyant jet releases in urban areas

    SciTech Connect

    Nand, K.; Olmos, M.

    1997-12-31

    As part of the Clean Air Act Amendments of 1990 (CAAA 1990), legislation was enacted requiring the performance of Risk Management Programs (RMPs) for facilities handling toxic substances and flammable materials. One of the three main components of the RMP is the hazard assessment, which requires the performance of air dispersion modeling and consequence analysis of identified accidental release scenarios for toxic substances and flammable materials. The emissions of toxic materials during accidental releases are typically of short duration, may be released as a vertical jet, and may also exhibit neutrally buoyant or dense gas behavior. The INPUFF model, a Gaussian integrated puff model is routinely used to study the dispersion of neutrally buoyant jet releases. Three dispersion algorithms are provided within the INPUFF model for studying the dispersion downwind of a source. The first option allows the use of classical Pasquill-Gifford scheme which is appropriate for rural locations. The second option allows the use of Irwin`s on-site scheme, and the third option allows the incorporation of user defined dispersion characteristics. However, most of the times, Option one is used for performing the dispersion analysis, even for accidental releases in urban areas. The use of INPUFF model with rural dispersion coefficients (Option 1) would result in improper estimates of hazard distances. The EPA has also developed the Industrial Source Complex Short Term (ISCST) Model for studying the atmospheric dispersion of steady state neutrally buoyant releases. A comparison of the rural dispersion coefficients in INPUFF and ISCST models indicated that both models use the same rural dispersion coefficients.

  1. Mushroom-Shaped Structures as Tracers of Buoyant Flow in the Galactic Disk

    E-print Network

    D'Avillez, M A; Avillez, Miguel A. de; Low, Mordecai-Mark Mac

    2001-01-01

    Recent HI emission observations of the Southern Galactic hemisphere have revealed a mushroom-like structure extending from z=-70 to -450 pc, composed of a stem and a cap. Similar structures occur in three-dimensional simulations of a dynamic galactic disk driven by isolated and clustered supernovae. Using these simulations, we show that hot gas in the Galactic disk that is not evacuated through chimneys expands into the cooler gas of the thick disk, forming mushroom-shaped structures. This new class of objects traces buoyant flow of hot gas into the thick disk.

  2. Mushroom-Shaped Structures as Tracers of Buoyant Flow in the Galactic Disk

    E-print Network

    Miguel A. de Avillez; Mordecai-Mark Mac Low

    2001-02-27

    Recent HI emission observations of the Southern Galactic hemisphere have revealed a mushroom-like structure extending from z=-70 to -450 pc, composed of a stem and a cap. Similar structures occur in three-dimensional simulations of a dynamic galactic disk driven by isolated and clustered supernovae. Using these simulations, we show that hot gas in the Galactic disk that is not evacuated through chimneys expands into the cooler gas of the thick disk, forming mushroom-shaped structures. This new class of objects traces buoyant flow of hot gas into the thick disk.

  3. 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.

  4. Cross-shelf penetrating fronts: A response of buoyant coastal water to ambient pycnocline undulation

    NASA Astrophysics Data System (ADS)

    Wu, Hui

    2015-07-01

    Offshore-penetrating tongues of coastal water have been frequently observed during the downwelling-favorable monsoon season at specific locations in waters off the Min-Zhe Coast, a region influenced by a buoyant coastal current originating from the Changjiang River. This process plays an important role in cross-shelf material exchange in the East China Sea (ECS), but the underlying mechanisms are not fully understood. This study suggests that the penetrating fronts are the response of buoyant coastal water to along-isobath undulation of the ambient pycnocline that is controlled by the temperature stratification in seawater. When the ambient pycnocline descends sharply in the downshelf direction, coastal water is transported offshore due to the joint effect of baroclinicity and relief (JEBAR), and thus generates a penetrating front. Along-isobath pycnocline undulation in the ECS can arise from nonuniform tidal mixing due to tidal wave divergence off the Min-Zhe Coast. Onshelf intrusion of cold and dense Kuroshio subsurface water prevents thorough mixing of the pycnocline. Different from the common cross-shelf transport phenomena induced by winds or frontal instabilities, such a tidal mechanism should produce penetrating fronts at specific locations, in agreement with observations.

  5. Dense nanoparticles exhibit enhanced vascular wall targeting over neutrally buoyant nanoparticles in human blood flow.

    PubMed

    Thompson, Alex J; Eniola-Adefeso, Omolola

    2015-07-15

    For vascular-targeting carrier (VTC) systems to be effective, carriers must be able to localize and adhere to the vascular wall at the target site. Research suggests that neutrally buoyant nanoparticles are limited by their inability to localize to the endothelium, making them sub-optimal as carriers. This study examines whether particle density can be exploited to improve the targeting (localization and adhesion) efficiency of nanospheres to the vasculature. Silica spheres with 500 nm diameter, which have a density roughly twice that of blood, exhibit improved adhesion to inflamed endothelium in an in vitro model of human vasculature compared to neutrally buoyant polystyrene spheres of the same size. Silica spheres also display better near-wall localization in the presence of red blood cells than they do in pure buffer, likely resulting in the observed improvement in adhesion. Titania spheres (4 times more dense than blood) adhere at levels higher than polystyrene, but only in conditions when gravity or centrifugal force acts in the direction of adhesion. In light of the wide array of materials proposed for use as carrier systems for drug delivery and diagnostics, particle density may be a useful tool for improving the targeting of diseased tissues. PMID:25870170

  6. 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.

  7. Submarine melting at tidewater glaciers: comparison of numerical modelling, buoyant plume theory and hydrographic data.

    NASA Astrophysics Data System (ADS)

    Slater, D. A.; Nienow, P. W.; Goldberg, D. N.; Cowton, T. R.; Sole, A. J.

    2014-12-01

    Observations of the mass balance of the Greenland ice sheet in recent decades have shown significant losses at the coastal margins through the thinning, speed-up and retreat of tidewater glaciers. Ocean forcing, via melting of submerged ice at the calving fronts of tidewater glaciers, has been identified as a possible driver of this behaviour. Such submarine melting may provide a significant direct contribution to the negative mass balance of the glacier and could also amplify calving rates. Quantification of submarine melting remains uncertain however since modelling of fjord circulation and submarine melting is challenging, hydrographic data from pro-glacial fjords are sparse and direct observation of submarine melting at a tidewater glacier has so far proved impossible. Here, we compare submarine melt rates obtained using buoyant plume theory to those from a numerical model (MITgcm), finding reasonable agreement between the two methods. We then use buoyant plume theory, due to its faster computational speed, to investigate the dependence of melt rate on subglacial discharge, subglacial channel size (and thus emerging flow velocity) and fjord-water temperature. Finally we apply the theory to real tidewater glaciers, finding significant gaps between modelled melt rates and those estimated from hydrographic data. We discuss possible reasons for such disagreements and their implications for constraining the importance of submarine melting to tidewater glacier mass balance.

  8. Emission, Structure and Optical Properties of Overfire Soot from Buoyant Turbulent Diffusion Flames

    NASA Astrophysics Data System (ADS)

    Koylu, Umit Ozgur

    The present study investigated soot and carbon monoxide emissions, and evaluated the optical properties of soot, in the overfire region of buoyant turbulent diffusion flames burning in still air. Soot and carbon monoxide emissions, and the corresponding correlation between these emissions, were studied experimentally. The optical properties of soot were investigated both experimentally and theoretically. The experiments involved gas (acetylene, propylene, ethylene, propane, methane) and liquid (toluene, benzene, n-heptane, iso-propanol, ethanol, methanol) fuels. The investigation was limited to the fuel-lean (overfire) region of buoyant turbulent diffusion flames burning in still air. Measurements included flame heights, characteristic flame residence times, carbon monoxide and soot concentrations, mixture fractions, ex-situ soot structure parameters (primary particle sizes, number of primary particles in aggregates, fractal dimensions), and in-situ optical cross sections (differential scattering, total scattering, and absorption) of soot in the overfire region of buoyant turbulent diffusion flames, emphasizing conditions in the long residence time regime where these properties are independent of position in the overfire region and flame residence time. The predictions of optical cross sections for polydisperse aggregates were based on Rayleigh-Debye-Gans theory for fractal aggregates; the predictions of this theory were evaluated by combining the TEM structure and the light scattering/extinction measurements. Carbon monoxide concentrations and mixture fractions were correlated in the overfire region of gas- and liquid -fueled turbulent diffusion flames. Soot volume fraction state relationships were observed for liquid fuels, supporting earlier observations for gas fuels. A strong correlation between carbon monoxide and soot concentrations was established in the fuel-lean region of both gas- and liquid-fueled turbulent diffusion flames. The structure and emission properties of soot were found to be invariant with respect to both position and flame residence time in the long residence time regime, implying useful generalizations of soot properties in the overfire region of turbulent diffusion flames. The optical cross sections of soot aggregates were found to be in good agreement with the polydisperse fractal Rayleigh -Debye-Gans theory, except in the near forward scattering direction where multiple scattering effects appear to be most important. However, the region where multiple scattering effects were important was limited for overfire soot, and had little effect on total scattering cross sections.

  9. Self induced buoyant blow off in upward flame spread on thin solid Michael C. Johnston a,n

    E-print Network

    length and steady spread rate. Flame blow off from the increased buoyancy induced air velocity (atSelf induced buoyant blow off in upward flame spread on thin solid fuels Michael C. Johnston a off Material flammability limits Upward burning limit One-sided extinction Flame spread SIBAL fuel a b

  10. 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

  11. Modification of the PPSP (Power Plant Research Program) dispersion model for highly buoyant plumes

    SciTech Connect

    Weil, J.C.; Corio, L.A.

    1988-06-01

    The report describes a modification of the PPSP dispersion model for tall stack plumes. The modification accounts for the dispersion of highly buoyant plumes that loft or remain near the top of the convective boundary layer and resist downward mixing. The main idea is that plume segments are mixed to the ground only by downdrafts with sufficient kinetic energy to overcome the potential energy difference between the plume and the ambient air. Simple analytical expressions are derived for the crosswind-integrated concentration and the ground-level concentration (GLC). They are based on the conservation of plume buoyancy, the probability distribution of the ambient vertical velocities, and the lateral plume spread. Evaluation of the modified model with GLCs around power plant stacks shows that it performs better than the original model.

  12. 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.

  13. A numerical study of the motion of a neutrally buoyant cylinder in two dimensional shear flow

    NASA Astrophysics Data System (ADS)

    Pan, Tsorng-Whay; Huang, Shih-Lin; Chen, Shih-Di; Chu, Chin-Chou; Chang, Chien-Cheng

    2012-11-01

    We have investigated the motion of a neutrally buoyant cylinder of circular or elliptic shape in two dimensional shear flow of a Newtonian fluid by direct numerical simulation. The numerical results are validated by comparisons with existing theoretical, experimental and numerical results, including a power law of the normalized angular speed versus the particle Reynolds number. The centerline between two walls is an expected equilibrium position of the cylinder mass center in shear flow. When placing the particle away from the centerline initially, it migrates toward another equilibrium position for higher Reynolds numbers due to the interplay between the slip velocity, the Magnus force, and the wall repulsion force. T-W Pan acknowledges the support by the US NSF and S-L Huang, S-D Chen, C-C Chu, C-C Chang acknowledge the support by the National Science Council of Taiwan, ROC.

  14. Buoyant thermal plumes from planetary landers and rovers: Application to sizing of meteorological masts

    NASA Astrophysics Data System (ADS)

    Lorenz, Ralph D.; Sotzen, Kristin S.

    2014-01-01

    Objective. Landers on Mars and Titan may have warm surfaces as a result of solar heating or the carriage of radioisotope power sources. This warmth can perturb downwind meteorological measurements, but cannot be modeled as a simple aerodynamic wake because buoyant forces can be significant. Methods. We use an analytic model from the industrial aerodynamics literature on smoke dispersion from fires and smokestacks to evaluate the plume trajectories. Computational Fluid Dynamics (CFD) simulations are also performed for a Titan lander. Results. CFD yields results similar to the analytic model. (Albeit with a possibly weaker dependence on windspeed than the classic model.) We apply the models to evaluate the probability of immersion of instrumentation in plumes from the Mars Science Laboratory (MSL) Curiosity and for a Titan lander under various wind scenarios. Conclusions. Lander perturbations can be easily calculated. Practice implications. None.

  15. Buoyant Effects on the Flammability of Silicone Samples Planned for the Spacecraft Fire Experiment (Saffire)

    NASA Technical Reports Server (NTRS)

    Niehaus, Justin E.; Ferkul, Paul V.; Gokoglu, Suleyman A.; Ruff, Gary A.

    2015-01-01

    Flammability experiments on silicone samples were conducted in anticipation of the Spacecraft Fire Experiment (Saffire). The sample geometry was chosen to match the NASA 6001 Test 1 specification, namely 5 cm wide by 30 cm tall. Four thicknesses of silicone (0.25, 0.36, 0.61 and 1.00 mm) were examined. Tests included traditional upward buoyant flame spread using Test 1 procedures, downward opposed-flow flame spread, horizontal and angled flame spread, and forced-flow upward and downward flame spread. In addition to these configurations, upward and downward tests were conducted in a chamber with varying oxygen concentrations. In the upward buoyant flame spread tests, the flame generally did not burn the entire sample. As thickness was increased, the flame spread distance decreased before flame extinguishment. For the thickest sample, ignition could not be achieved. In the downward tests, the two thinnest samples permitted the flame to burn the entire sample, but the spread rate was lower compared to the corresponding upward values. The other two thicknesses could not be ignited in the downward configuration. The increased flammability for downward spreading flames relative to upward ones is uncommon. The two thinnest samples also burned completely in the horizontal configuration, as well as at angles up to 75 degrees from the horizontal. Upward tests in air with an added forced flow were more flammable. The upward and downward flammability behavior was compared in atmospheres of varying oxygen concentration to determine a maximum oxygen concentration for each configuration. Complementary analyses using EDS, TGA, and SEM techniques suggest the importance of the silica layer deposited downstream onto the unburned sample surface.

  16. 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).

  17. Buoyant Effects on the Flammability of Silicone Samples Planned for the Spacecraft Fire Experiment (Saffire)

    NASA Technical Reports Server (NTRS)

    Niehaus, Justin; Ferkul, Paul V.; Gokoglu, Suleyman; Ruff, Gary

    2015-01-01

    Flammability experiments on silicone samples were conducted in anticipation of the Spacecraft Fire Experiment (Saffire). The sample geometry was chosen to match the NASA 6001 Test 1 specification, namely 5 cm wide by 30 cm tall. Four thicknesses of silicone (0.25, 0.36, 0.61 and 1.00 mm) were examined. Tests included traditional upward buoyant flame spread using Test 1 procedures, downward opposed flow flame spread, horizontal and angled flame spread, forced flow upward and downward flame spread. In addition to these configurations, upward and downward tests were also conducted in a chamber with varying oxygen concentrations. In the upward buoyant flame spread tests, the flame generally did not burn the entire sample. As thickness was increased, the flame spread distance decreased before flame extinguishment. For the thickest sample, ignition could not be achieved. In the downward tests, the two thinnest samples permitted the flame to burn the entire sample, but the spread rate was lower compared to the corresponding upward values. The other two thicknesses could not be ignited in the downward configuration. The increased flammability for downward spreading flames relative to upward ones is uncommon. The two thinnest samples also burned completely in the horizontal configuration, as well as at angles up to 75 degrees from the horizontal. The upward and downward flammability behavior was compared in atmospheres of varying oxygen concentration to determine a maximum oxygen concentration for each configuration. Upward tests in air with an added forced flow were more flammable. Complementary analyses using SEM and TGA techniques suggest the importance of the silica layer formed on the burned sample surface. As silicone burns upward, silica deposits downstream •If the silicone is ignited in the downward configuration, it burns the entire length of the sample •Burning upward at an angle increases the burn length in some cases possibly due to less silica deposition •Forced flow in the upward burning case increases flammability, likely due to an increase in convective flow preventing silica from depositing •Samples in upward configuration burning under forced flow self extinguish after forced flow is removed

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

    SciTech Connect

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

    2007-02-15

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

  19. 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

    ... closure for buoyant vests must— (1) Be tested for weathering. The Coast Guard will determine which one or...) for 24 hours; and (2) Within 5 minutes of completion of the weathering test required by paragraph...

  20. 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

    ... closure for buoyant vests must— (1) Be tested for weathering. The Coast Guard will determine which one or...) for 24 hours; and (2) Within 5 minutes of completion of the weathering test required by paragraph...

  1. 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

    ... closure for buoyant vests must— (1) Be tested for weathering. The Coast Guard will determine which one or...) for 24 hours; and (2) Within 5 minutes of completion of the weathering test required by paragraph...

  2. 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

    ... closure for buoyant vests must— (1) Be tested for weathering. The Coast Guard will determine which one or...) for 24 hours; and (2) Within 5 minutes of completion of the weathering test required by paragraph...

  3. 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

    ... closure for buoyant vests must— (1) Be tested for weathering. The Coast Guard will determine which one or...) for 24 hours; and (2) Within 5 minutes of completion of the weathering test required by paragraph...

  4. 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

  5. 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.

  6. FPluMe: An integral eruption column model based on the Buoyant Plume Theory

    NASA Astrophysics Data System (ADS)

    Folch, Arnau; Costa, Antonio; Macedonio, Giovanni

    2015-04-01

    Estimates of mass flow rate from volcanic eruption columns are crucial for ash dispersion models, used to assess hazard on population and civil aviation. We present a practical model of eruption column model based on the Buoyant Plume Theory (BPT) that accounts for the effect of the atmospheric wind that results in the bending over of the plume trajectory and increases the entrainment of ambient air. The model solves the equations for the conservation of mass, momentum and energy in terms of averaged variables, accounting for fallout and re-entrainment of tephra from and into the column and particle aggregation. For some given atmospheric conditions and a wind profile, the model can be used to determine the height at which volcanic plumes spread in the atmosphere if mass flow rate at the vent is known, or to estimate mass flow rate when the eruption column height is known. For a given column height, if wind effects are not properly accounted for, the values of the mass flow rate can be significantly underestimated. Our model calculations are compared with proposed semi-empirical relationships between the plume height and the source mass flux that account for the atmospheric wind effect.

  7. 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.

  8. Experiments in vision-based control of a neutrally buoyant free-flyer

    NASA Astrophysics Data System (ADS)

    Alexander, Harold L.; Eberly, Kurt; Weigl, Harald J.

    1992-02-01

    The Laboratory for Space Teleoperation and Robotics is developing a neutrally-buoyant robot for research into the automatic and teleoperated (remote human) control of unmanned robotic vehicles for use in space. The goal of this project is to develop a remote robot with maneuverability and dexterity comparable to that of a space-suited astronaut with a manned maneuvering unit, able to assume many of the tasks currently planned for astronauts during extravehicular activity (EVA). Such a robot would be able to spare the great expense and hazards associated with human EVA, and make possible much less expensive scientific and industrialization exploitation of orbit. Both autonomous and teleoperated control experiments will require the vehicle to be able to automatically control its position and orientation. The laboratory is developing vision-based vehicle navigation system that works by tracking features in video images from cameras mounted on the vehicle and trained at a special target fixed in the environment. The methods are adaptable to a variety of video-based tracking systems, and are based on a linearized vision model, receiving as inputs image feature coordinates at each time step This paper includes a description of the underwater vehicle and the vision system.

  9. Wave-induced mixing and transport of buoyant particles: application to the Statfjord A oil spill

    NASA Astrophysics Data System (ADS)

    Drivdal, M.; Broström, G.; Christensen, K. H.

    2014-12-01

    This study focuses on how wave-current and wave-turbulence interactions modify the transport of buoyant particles in the ocean. Here the particles can represent oil droplets, plastic particles, or plankton such as fish eggs and larvae. Using the General Ocean Turbulence Model (GOTM), 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, affects the drift of the particles. The energy and momentum fluxes, as well as the Stokes drift, depend on the directional wave spectrum obtained from a wave model. As a first test, the depth and velocity scales from the model are compared with analytical solutions based on a constant eddy viscosity (i.e., classical Ekman theory). Secondly, the model is applied to a case in which we investigate the oil drift after an oil spill off the west coast of Norway in 2007. During this accident the average net drift of oil was observed to be both slower and more deflected away from the wind direction than predicted by oil-drift models. In this case, using wind and wave forcing from the ERA Interim archive it is shown that the wave effects are important for the resultant drift and have the potential to improve drift forecasting.

  10. Experiments on the fragmentation of a buoyant liquid volume in another liquid

    NASA Astrophysics Data System (ADS)

    Landeau, Maylis; Deguen, Renaud; Olson, Peter

    2013-11-01

    Buoyancy-driven fragmentation of one liquid in another immiscible liquid was a common process during the formation of the terrestrial planets. Another example of this phenomenon is the sudden release of petroleum into the ocean during the Deepwater Horizon disaster. In this study, we present experiments on the instability and fragmentation of volumes of heavier liquid released into lighter immiscible liquids. We characterize the different fragmentation regimes in parameter space. We find that, at low and intermediate Weber numbers (measuring the importance of inertia versus surface tension forces), the fragmentation regime mainly results from a competition between the growth of Rayleigh-Taylor instabilities and the roll-up of a vortex ring. At high Weber numbers, a turbulent fragmentation regime is found, and the large-scale flow behaves as a turbulent vortex ring or a turbulent thermal. An integral model based on the entrainment assumption, and adapted to buoyant vortex rings with initial momentum, is consistent with our experimental data. This indicates that the concept of turbulent entrainment is valid for non-dispersed immiscible fluids at large Weber and Reynolds numbers.

  11. Laminar-turbulent transition of channel flows: the effect of neutrally buoyant finite-size particles

    NASA Astrophysics Data System (ADS)

    Abbas, Micheline; Loisel, Vincent; Masbernat, Olivier; Climent, Eric

    2013-11-01

    Numerical simulations were performed on channel flows laden with resolved finite-size neutrally buoyant particles at moderate volumetric concentration. In the case of fluctuating flows close to laminar-turbulent transition, the particle volume fraction is homogeneously distributed in the channel except an accumulation layer in the near-wall region (particle migration is driven by inertia). Particles increase the level of perturbations close to the wall leading to significant enhancement of both the velocity fluctuations and the wall friction coefficient. Additionally, particles break down the large-scale flow structures into smaller, more numerous and sustained eddies. When the flow Reynolds number is decreased, flow relaminarization occurs at critical Reynolds number RecS (based on the effective suspension viscosity) significantly below the critical Reynolds number Rec of single-phase flow transition. In the case of laminar flows, the suspension segregates into pure fluid and particle laden wall layers due to cross-stream migration. An instability is observed characterized by the formation of dune-like patterns at the separation between pure fluid and concentrated suspension. Increasing the Reynolds number yields transition to turbulence at a threshold above RecS . This work was granted access to the HPC resources of CALMIP and GENCI under the allocations 2012-P1002 and x20132a6942 respectively.

  12. Turbulence Modeling Effects on the Prediction of Equilibrium States of Buoyant Shear Flows

    NASA Technical Reports Server (NTRS)

    Zhao, C. Y.; So, R. M. C.; Gatski, T. B.

    2001-01-01

    The effects of turbulence modeling on the prediction of equilibrium states of turbulent buoyant shear flows were investigated. The velocity field models used include a two-equation closure, a Reynolds-stress closure assuming two different pressure-strain models and three different dissipation rate tensor models. As for the thermal field closure models, two different pressure-scrambling models and nine different temperature variance dissipation rate, Epsilon(0) equations were considered. The emphasis of this paper is focused on the effects of the Epsilon(0)-equation, of the dissipation rate models, of the pressure-strain models and of the pressure-scrambling models on the prediction of the approach to equilibrium turbulence. Equilibrium turbulence is defined by the time rate (if change of the scaled Reynolds stress anisotropic tensor and heat flux vector becoming zero. These conditions lead to the equilibrium state parameters. Calculations show that the Epsilon(0)-equation has a significant effect on the prediction of the approach to equilibrium turbulence. For a particular Epsilon(0)-equation, all velocity closure models considered give an equilibrium state if anisotropic dissipation is accounted for in one form or another in the dissipation rate tensor or in the Epsilon(0)-equation. It is further found that the models considered for the pressure-strain tensor and the pressure-scrambling vector have little or no effect on the prediction of the approach to equilibrium turbulence.

  13. Wave induced mixing and transport of buoyant particles: application to the Statfjord A oil spill

    NASA Astrophysics Data System (ADS)

    Drivdal, M.; Broström, G.; Christensen, K. H.

    2014-05-01

    The modelling of wave-current and wave-turbulence interactions have received much attention in recent years. In this study the focus is on how these wave effects modify the transport of particles in the ocean. Here the particles are buoyant tracers that can represent oil droplets, plastic particles or plankton, for example fish eggs and larvae. Using the General Ocean Turbulence Model (GOTM), 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 affect the drift of the particles. 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. As a first test the depth and velocity scales from the model are compared with analytical solutions based on a constant eddy viscosity (e.g. classical Ekman theory). Secondly the model is applied to a case where we investigate the oil drift after an offshore oil spill outside the western coast of Norway in 2007. During this accident the average net drift of oil was observed to be both slower and more deflected away from the wind direction than predicted by empirical models. With wind and wave forcing from the ERA Interim archive, it is shown that the wave effects are important for the resultant drift in this case, and has the potential to improve drift forecasting.

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

    SciTech Connect

    Evans, G.; Greif, R.

    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.

  15. 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).

  16. The Flow of Buoyant Meltwater Next to Ice Shelves and Icebergs

    NASA Astrophysics Data System (ADS)

    Wells, A. J.; Worster, G.

    2008-12-01

    Melting at the base of an ice shelf can play a significant role in the polar oceans, contributing to the mass balance of the ice shelf and leading to the formation of Ice Shelf Water. Fresh meltwater is relatively buoyant compared to the surrounding ocean and can rise along the ice surface, with the strength of this flow depending critically on the heat and salt fluxes from the ocean to the ice. We justify a simplified theoretical model that describes the coupling of heat and salt fluxes with the buoyancy- driven flow of meltwater, next to both vertical and sloping ice surfaces. The flow develops with distance along the ice surface, and different flow regimes can be obtained depending on the length and the slope of the ice surface. Both the heat and salt fluxes differ between the two regimes. On moderate scales the flow is controlled by buoyancy in a narrow region close to the ice surface. This predicts that the melting rate is independent of distance along the ice surface, consistent with previous laboratory scale measurements of heat transfer. This regime may be important for ablation at the sides of tabular icebergs, and under some regions of ice shelves. Further downstream, the flow is dominated by buoyancy located further from the wall, and can be described by a model similar to those often used to model ice-shelf-water plumes. This predicts that the melting rate increases with distance along the ice surface. Simple analytic solutions are also derived for flow in an unstratified fluid, which indicate the possible sensitivity of the ablation rate to changes in ocean temperature. The predicted variation of the heat and salt fluxes with distance along the ice surface may have important consequences for more complex models of ice-shelf-water flow.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Filament formation and evolution in buoyant coastal waters: Observation and modelling

    NASA Astrophysics Data System (ADS)

    Iermano, Ilaria; Liguori, Giovanni; Iudicone, Daniele; Buongiorno Nardelli, Bruno; Colella, Simone; Zingone, Adriana; Saggiomo, Vincenzo; Ribera d'Alcalà, Maurizio

    2012-11-01

    This paper presents a detailed analysis of the formation and subsequent evolution of filament-like structures observed in a relatively small area of the mid-Tyrrhenian Sea (Mediterranean Sea). The filament dynamics and potential impact on the cross-shelf exchange budget are investigated based on a combined use of remote sensing imagery, in situ data and numerical modelling. The complexity of these phenomena is shown by focusing on four distinct events that led to cross-shelf transport, each representative of a different dynamic process and a distinct expected impact on the coastal area. A systematic analysis of available observations for the years 1998-2006 underlines the role of the interplay of atmospheric freshwater fluxes, river loads and wind stress variations, which may create favourable conditions for the convergence of shelf waters (particularly at coastal capes) and the subsequent formation of short-lived filaments along the coast. The response of the buoyant coastal waters to periods of wind reversal and fluctuating freshwater discharge rates is examined through idealised Regional Ocean Modeling System (ROMS) simulations. The filaments observed in remote sensing imagery were well reproduced by the numerical exercise, where the filaments appear as organised submesoscale structures that possess high relative vorticity and develop at the river mouths or adjacent capes. In both scenarios, the filaments appear largely determined by (i) the presence of a buoyancy anomaly, (ii) the angle between the wind pulse direction and the coast and (iii) irregularities in the coastal profile. The ensemble of results suggests that the occurrence of such transient, intense structures may contribute considerably to the biological variability and cross-shelf exchange in coastal areas with similar traits.

  2. Trench Advance By the Subduction of Buoyant Features - Application to the Izu-Bonin-Marianas Arc

    NASA Astrophysics Data System (ADS)

    Goes, S. D. B.; Fourel, L.; Morra, G.

    2014-12-01

    Most subduction trenches retreat, not only today but throughout the Cenozoic. However, a few trenches clearly advance during part of the evolution, including Izu-Bonin Marianas (IBM) and Kermadec. Trench retreat is well understood as a basic consequence of slab pull, but it is debated what causes trench advance. The IBM trench underwent a complex evolution: right after its initiation, it rotated clockwise, leading to very fast retreat in the north and slow retreat in the south. But since 10-15 Ma, IBM trench motions have switched to advance at the southern end, and since 5 Ma also the northern end is advancing. Based on 2-D subduction models, it has been proposed proposed that the change in age of the subducting plate at the IBM trench (from 40-70 m.y. at the initiation of the trench 45 m.y. ago to 100-140 m.y. lithosphere subducting at the trench today) and its effect on plate strength could explain the transition from trench retreat to trench advance, and that the age gradient (younger in the north and older in the south) could explain the rotation of the trench. However, with new 3-D coupled fluid-solid subduction model where we can include such lateral age gradients, we find that this does not yield the observed behaviour. Instead, we propose an alternative mechanism, involving the subduction of the buoyant Caroline Island Ridge at the southern edge of the Mariana trench and show that it can explain both trench motion history and the current morphology of the IBM slab as imaged by seismic tomography.

  3. Trace Metal and Sulfur Dynamics in the First Meter of Buoyant Hydrothermal Vent Plumes

    NASA Astrophysics Data System (ADS)

    Findlay, A.; Gartman, A.; Shaw, T. J.; Luther, G. W., III

    2014-12-01

    The speciation and reactivity of metals and metal sulfides within the buoyant plume is critical to determining the ultimate fate of metals emitted from hydrothermal vents. The concentration, size fractionation, and partitioning of trace metals (Fe, Mn, Cu, Co, Zn, Cd, Pb) were determined within the first meter of the rising plume at three vent fields (TAG, Snakepit, and Rainbow) along the Mid-Atlantic Ridge. At Rainbow, total Fe concentrations exceed total sulfide concentrations by an order of magnitude, whereas at the other two sites, total Fe and total sulfide concentrations are nearly equal. At all three sites, Mn and Fe are primarily in the filtered (< 0.2 ?m) fraction and Cu, Co, Zn, Cd, and Pb are mainly in the unfiltered fraction. At TAG and Snakepit, unfiltered copper is correlated with unfiltered cobalt, and unfiltered zinc is correlated with unfiltered cadmium and lead. At Rainbow, unfiltered zinc, cadmium and lead are correlated, but unfiltered copper and cobalt are not, indicating precipitation dynamics at Rainbow are different than those at TAG and Snakepit due to bulk geochemical differences, including a higher iron to sulfide ratio. A sequential HCl/HNO3 leaching method was used to distinguish metals present in pyrite and chalcopyrite in both unfiltered and filtered samples. Significant portions of unfiltered Cu and Co were extracted in HNO3, whereas unfiltered Zn, Cd, and Pb were extracted in HCl. Up to 95 % of filtered Cu, Co, and Zn, up to 80% Cd, and up to 60 % Pb are only extractable in HNO3, indicating that a significant portion of metals < 0.2 ?m are incorporated into a recalcitrant fraction such as nanoparticulate pyrite or chalcopyrite.

  4. Passive buoyant tracers in the ocean surface boundary layer: 1. Influence of equilibrium wind-waves on vertical distributions

    NASA Astrophysics Data System (ADS)

    Kukulka, T.; Brunner, K.

    2015-05-01

    This paper is the first of a two part series that investigates passive buoyant tracers in the ocean surface boundary layer. The first part examines the influence of equilibrium wind-waves on vertical tracer distributions, based on large eddy simulations (LES) of the wave-averaged Navier-Stokes equation. The second part applies the model to investigate observations of buoyant microplastic marine debris, which has emerged as a major ocean pollutant. The LES model captures both Langmuir turbulence (LT) and enhanced turbulent kinetic energy input due to breaking waves (BW) by imposing equilibrium wind-wave statistics for a range of wind and wave conditions. Concentration profiles of LES agree well with analytic solutions obtained for an eddy diffusivity profile that is constant near the surface and transitions into the K-Profile Parameterization (KPP) profile shape at greater depth. For a range of wind and wave conditions, the eddy diffusivity normalized by the product of water-side friction velocity and mixed layer depth, h, mainly depends on a single nondimensional parameter, the peak wavelength (which is related to Stokes drift decay depth) normalized by h. For smaller wave ages, BW critically enhances near-surface mixing, while LT effects are relatively small. For greater wave ages, both BW and LT contribute to elevated near-surface mixing, and LT significantly increases turbulent transport at greater depth. We identify a range of realistic wind and wave conditions for which only Langmuir (and not BW or shear driven) turbulence is capable of deeply submerging buoyant tracers.

  5. The impact of buoyant gas-phase flow and heterogeneity on thermo-hydrological behavior at Yucca Mountain

    SciTech Connect

    Buscheck, T.A.; Nitao, J.J.

    1994-01-01

    To safety and permanently store high-level nuclear waste, the potential Yucca Mountain repository system must mitigate the release and transport of radionuclides for tens of thousands of years. In the failure scenario of greatest concern, water would contact a waste package, accelerate its failure rate, and eventually transport radionuclides to the water table. Our analyses have demonstrated that the only significant source of liquid water is fracture flow from: (1) natural infiltration, (2) condensate drainage generated under boiling conditions, and (3) condensate drainage generated under sub-boiling conditions. The first source of liquid water arises from the ambient system; the second and third sources are generated by repository heat. Buoyant, gas-phase flow, occurring either on a sub-repository scale or on a mountain scale, may play an important role in generating the second and third sources of liquid water. By considering a wide range in bulk permeability of the fractured rock, we identify a threshold bulk permeability at which buoyant, gas-phase convection begins to dominate hydrological behavior. At 10 times this threshold, convection begins to dominate thermal behavior. These effects can dominate moisture movement in the unsaturated zone on the order of 100,000 yr. We find that the development of a large above-boiling zone suppresses the effects of buoyant vapor flow. Zones of sharply contrasting bulk permeability also influence condensate generation and drainage. Of particular concern are conditions that focus vapor flow and condensate drainage, which could result in persistent refluxing at the repository, causing water to drip onto waste packages. These effects can occur under both sub-boiling and boiling conditions Long-term in situ heater tests are required to diagnose the potential for major repository-heat- driven sources of fractures flow.

  6. 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.

  7. Numerical study of a buoyant plume from a multi-flue stack into a variable temperature gradient atmosphere.

    PubMed

    Velamati, Ratna Kishore; Vivek, M; Goutham, K; Sreekanth, G R; Dharmarajan, Santosh; Goel, Mukesh

    2015-11-01

    Air pollution is one of the major global hazards and industries have been one of its major contributors. This paper primarily focuses on analyzing the dispersion characteristics of buoyant plumes of the pollutant released from a multi-flue vertical stack into a variable temperature gradient atmosphere (?) in a constant-velocity cross wind using two stack configurations-inline and parallel. The study is conducted for different Froude numbers, Fr?=?12.64, 9.55, and 8.27. The atmospheric temperature gradients considered for the study are 0, +1, +1.5, and +2 K/100 m. The numerical study is done using the commercial computational fluid dynamics (CFD) code FLUENT. The effects of stack configuration, ?, and Fr on the plume characteristics are presented. It is observed that the plume rises higher and disperses over a larger area with the inline configuration due to better mixing and shielding effect. With higher ?, it is seen that the plume rises initially and then descends due to variation of the buoyant force. The plume rise initially is strongly influenced by the momentum of the jet, and as it moves downstream, it is influenced by the cooling rate of the plume. Furthermore, the plume rises higher and disperses over a larger area with a decrease in Fr. PMID:26099599

  8. Magnetic Fields in Massive Stars. II. The Buoyant Rise of Magnetic Flux Tubes Through the Radiative Interior

    E-print Network

    K. B. MacGregor; J. P. Cassinelli

    2002-12-10

    We present results from an investigation of the dynamical behavior of buoyant magnetic flux rings in the radiative interior of a uniformly rotating early-type star. Our physical model describes a thin, axisymmetric, toroidal flux tube that is released from the outer boundary of the convective core, and is acted upon by buoyant, centrifugal, Coriolis, magnetic tension, and aerodynamic drag forces. We find that rings emitted in the equatorial plane can attain a stationary equilibrium state that is stable with respect to small displacements in radius, but is unstable when perturbed in the meridional direction. Rings emitted at other latitudes travel toward the surface along trajectories that largely parallel the rotation axis of the star. Over much of the ascent, the instantaneous rise speed is determined by the rate of heating by the absorption of radiation that diffuses into the tube from the external medium. Since the time scale for this heating varies like the square of the tube cross-sectional radius, for the same field strength, thin rings rise more rapidly than do thick rings. For a reasonable range of assumed ring sizes and field strengths, our results suggest that buoyancy is a viable mechanism for bringing magnetic flux from the core to the surface, being capable of accomplishing this transport in a time that is generally much less than the stellar main sequence lifetime.

  9. Use of a Force Sensor in Archimedes' Principle Experiment, Determination of Buoyant Force and Acceleration Due To Gravity

    NASA Astrophysics Data System (ADS)

    Aurora, Tarlok

    2013-04-01

    In introductory physics, students verify Archimedes' principle by immersing an object in water in a container, with a side-spout to collect the displaced water, resulting in a large uncertainty, due to surface tension. A modified procedure was introduced, in which a plastic bucket is suspended from a force sensor, and an object hangs underneath the bucket. The object is immersed in water in a glass beaker (without any side spout), and the weight loss is measured with a computer-controlled force sensor. Instead of collecting the water displaced by the object, tap water was added to the bucket to compensate for the weight loss, and the Archimedes' principle was verified within less than a percent. With this apparatus, buoyant force was easily studied as a function of volume of displaced water; as well as a function of density of saline solution. By graphing buoyant force as a function of volume (or density of liquid), value of g was obtained from slope. Apparatus and sources of error will be discussed.

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

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

  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, 2014 CFR

    2014-10-01

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

  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, 2013 CFR

    2013-10-01

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

  13. 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

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

  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, 2011 CFR

    2011-10-01

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

  15. 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

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

  16. 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

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

  17. 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

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

  18. 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

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

  19. 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

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

  20. 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

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

  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, 2011 CFR

    2011-10-01

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

  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, 2012 CFR

    2012-10-01

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

  3. 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

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

  4. 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

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

  5. 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

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

  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, 2010 CFR

    2010-10-01

    ... LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Kapok or Fibrous Glass, Adult and Child § 160.047-3a... tested for weathering. The Coast Guard will determine which one or more of the following tests will be used: (i) Application of a 20 percent sodium-chloride solution spray at a temperature of 95 °F (35...

  7. 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

    ... LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Kapok or Fibrous Glass, Adult and Child § 160.047-3a... tested for weathering. The Coast Guard will determine which one or more of the following tests will be used: (i) Application of a 20 percent sodium-chloride solution spray at a temperature of 95 °F (35...

  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, 2011 CFR

    2011-10-01

    ... LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Kapok or Fibrous Glass, Adult and Child § 160.047-3a... tested for weathering. The Coast Guard will determine which one or more of the following tests will be used: (i) Application of a 20 percent sodium-chloride solution spray at a temperature of 95 °F (35...

  9. 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

    ... LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Kapok or Fibrous Glass, Adult and Child § 160.047-3a... tested for weathering. The Coast Guard will determine which one or more of the following tests will be used: (i) Application of a 20 percent sodium-chloride solution spray at a temperature of 95 °F (35...

  10. 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

    ... LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Kapok or Fibrous Glass, Adult and Child § 160.047-3a... tested for weathering. The Coast Guard will determine which one or more of the following tests will be used: (i) Application of a 20 percent sodium-chloride solution spray at a temperature of 95 °F (35...

  11. An oscillating motion of a red blood cell and a neutrally buoyant particle in Poiseuille flow in a narrow channel

    E-print Network

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

    2013-01-01

    Two motions of oscillation and vacillating breathing (swing) of a red blood cell have been observed in bounded Poiseuille flows (Phys. Rev. E 85, 16307 (2012)). To understand such motions, we have studied the oscillating motion of a neutrally buoyant rigid particle of the same shape in Poiseuille flow in a narrow channel and obtained that the crucial point is to have the particle interacting with Poiseuille flow with its mass center moving up and down in the channel central region. Since the mass center of the cell migrates toward the channel central region, its oscillating motion of the inclination angle is similar to the aforementioned motion as long as the cell keeps the shape of long body. But as 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 approaches to a fixed angle.

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. 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.

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

    NASA Astrophysics Data System (ADS)

    Smoot, N. Christian

    1997-03-01

    Bathymetry shows the regional interaction of aseismic, buoyant highs in northern Pacific subduction zones. Seamounts, ridges, and fractures on the seaward side of the trench are associated with events that do not support the accepted plate-tectonics paradigm, including an altered slab dip angle (Benioff zone) and the clustered volcanoes and earthquakes within the convergent margin. Most of the examples in this study show a reduction in the number of total earthquakes but an increase in the deeper earthquakes, an abnormal amount of across-trench deformation, and a larger amount of volcanism on the active arc than if no bouyant highs existed in the subduction zone. The connections between the seaward highs and the landward clustered highs are the transverse faults, which widen by turbidite scour as they age. Forearc canyons are the modern-day bathymetdc expression of these faults. All of the parameters introduced disagree with the plate-tectonic hypothesis, making an alternate explanation for the genesis necessary. That explanation falls into the realm of the surge-tectonic hypothesis, which can explain by fluid mechanics and eastward flow each of the introduced parameters.

  19. Surface manifestations of internal waves investigated by a subsurface buoyant jet: 3. Surface manifestations of internal waves

    NASA Astrophysics Data System (ADS)

    Bondur, V. G.; Grebenyuk, Yu. V.; Ezhova, E. V.; Kazakov, V. I.; Sergeev, D. A.; Soustova, I. A.; Troitskaya, Yu. I.

    2010-08-01

    In a large test reservoir at the Institute of Applied Physics, Russian Academy of Sciences, a series of experiments were performed to investigate the surface manifestations of internal waves radiated by a subsurface buoyant jet. The field of currents on the water surface of the reservoir was studied through the distribution of temperature with shallow thermocline. Using Particle Tracking Velocimetry (PTV), the velocity field of surface currents was measured. A theoretical model was developed to calculate the rates of disturbances on the surface. A comparison with experimental data indicated that the calculated data of the surface rate value are overestimated. This discrepancy was explained by the presence of a film of surface-active substances (SASs) with experimentally obtained parameters. Using scale modeling coefficients, we estimated the parameters of internal waves radiated by the subsurface wastewater system and the values of their surface manifestations in field conditions. We estimated the hydrodynamic contrasts in the field of surface waves, which can be caused by these inhomogeneous currents on the surface. For a wind velocity of 5 m/s, the magnitude of the contrast in the field of short waves can reach up to 10-25%, which is detected with confidence by remote-sensing methods.

  20. Multi-parametric Study of Rising 3D Buoyant Flux Tubes in an Adiabatic Stratification Using AMR

    NASA Astrophysics Data System (ADS)

    Martínez-Sykora, Juan; Moreno-Insertis, Fernando; Cheung, Mark C. M.

    2015-11-01

    We study the buoyant rise of magnetic flux tubes embedded in an adiabatic stratification using two-and three-dimensional, magnetohydrodynamic simulations. We analyze the dependence of the tube evolution on the field line twist and on the curvature of the tube axis in different diffusion regimes. To be able to achieve a comparatively high spatial resolution we use the FLASH code, which has a built-in Adaptive Mesh Refinement (AMR) capability. Our 3D experiments reach Reynolds numbers that permit a reasonable comparison of the results with those of previous 2D simulations. When the experiments are run without AMR, hence with a comparatively large diffusivity, the amount of longitudinal magnetic flux retained inside the tube increases with the curvature of the tube axis. However, when a low-diffusion regime is reached by using the AMR algorithms, the magnetic twist is able to prevent the splitting of the magnetic loop into vortex tubes and the loop curvature does not play any significant role. We detect the generation of vorticity in the main body of the tube of opposite sign on the opposite sides of the apex. This is a consequence of the inhomogeneity of the azimuthal component of the field on the flux surfaces. The lift force associated with this global vorticity makes the flanks of the tube move away from their initial vertical plane in an antisymmetric fashion. The trajectories have an oscillatory motion superimposed, due to the shedding of vortex rolls to the wake, which creates a Von Karman street.

  1. Large Scale Gas Mixing and Stratification Triggered by a Buoyant Plume With and Without Occurrence of Condensation

    SciTech Connect

    Paladino, Domenico; Auban, Olivier; Zboray, Robert

    2006-07-01

    The benefits of using codes with 3-D capabilities to address safety issues of LWRs will be applicable to both the current generation of nuclear reactors as well to future ALWRs. The phenomena governing the containment response in case of some postulated severe accident scenarios include gas (air, hydrogen, steam) stratification in the containment, gas distribution between containment compartments, wall condensation, etc. These phenomena are driven by buoyant high momentum injection (jets) and/or low momentum injection (plumes). For instance, mixing in the immediate vicinity of the postulated line break is mainly dominated by very high velocity efflux, while low-momentum flows are responsible for most of the transport processes within the containment. A project named SETH is currently in progress under the auspices of 15 OECD countries, with the aim of creating an experimental database suitable to assess the 3-D code capabilities in analyzing key-physical phenomena relevant for LWR safety analysis. This paper describes some results of two SETH tests, performed in the PANDA facility (located at PSI in Switzerland), focusing on plumes flowing near a containment wall. The plumes are generated by injecting a constant amount of steam in one of two interconnected vessels initially filled with air. In one of the two tests the temperature of the injected steam and the initial containment wall and fluid temperatures allowed for condensation during the test. (authors)

  2. Sink and swim: kinematic evidence for lifting-body mechanisms in negatively buoyant electric rays Narcine brasiliensis.

    PubMed

    Rosenblum, Hannah G; Long, John H; Porter, Marianne E

    2011-09-01

    Unlike most batoid fishes, electric rays neither oscillate nor undulate their body disc to generate thrust. Instead they use body-caudal-fin (BCF) locomotion. In addition, these negatively buoyant rays perform unpowered glides as they sink in the water column. In combination, BCF swimming and unpowered gliding are opposite ends on a spectrum of swimming, and electric rays provide an appropriate study system for understanding how the performance of each mode is controlled hydrodynamically. We predicted that the dorso-ventrally flattened body disc generates lift during both BCF swimming and gliding. To test this prediction, we examined 10 neonate lesser electric rays, Narcine brasiliensis, as they swam and glided. From video, we tracked the motion of the body, disc, pelvic fins and tail. By correlating changes in the motions of those structures with swimming performance, we have kinematic evidence that supports the hypothesis that the body disc is generating lift. Most importantly, both the pitch of the body disc and the tail, along with undulatory frequency, interact to control horizontal swimming speed and Strouhal number during BCF swimming. During gliding, the pitch of the body disc and the tail also interact to control the speed on the glide path and the glide angle. PMID:21832137

  3. The motion of a neutrally buoyant particle of an elliptic shape in two dimensional shear flow: A numerical study

    NASA Astrophysics Data System (ADS)

    Huang, Shih-Lin; Chen, Shih-Di; Pan, Tsorng-Whay; Chang, Chien-Cheng; Chu, Chin-Chou

    2015-08-01

    In this article, we investigate the motion of a neutrally buoyant particle of an elliptic shape freely moving in two dimensional shear flow by direct numerical simulation. An elliptic shape particle in shear flow, when initially being placed at the middle between two walls, either keeps rotating or has a stationary inclination angle depending on the particle Reynolds number R e = G r ra 2 / ? , where Gr is the shear rate, ra is the semi-long axis of the elliptic particle, and ? is the kinetic viscosity of the fluid. The critical particle Reynolds number Recr for the transition from a rotating motion to a stationary orientation depends on the aspect ratio AR = rb/ra and the confined ratio K = 2ra/H, where rb is the semi-short axis of the elliptic particle and H is the distance between two walls. Although the increasing of either parameters makes an increase in Recr, the dynamic mechanism is distinct. The AR variation causes the change of geometry shape; however, the K variation influences the wall effect. The stationary inclination angle of non-rotating slender elliptic particle with smaller confined ratio seems to depend only on the value of Re - Recr. An expected equilibrium position of the particle mass center in shear flow is the centerline between two walls. When placing the particle away from the centerline initially, it migrates either toward an equilibrium height away from the middle between two walls or back to the middle depending on the confined ratio and particle Reynolds number; but for higher particle Reynolds numbers, besides the previous two positions, the elliptic particle placed close to the middle just moves parallel to the wall with a stationary orientation.

  4. 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.

  5. 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.

  6. 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.

  7. 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…

  8. 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.

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

    SciTech Connect

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

    1997-01-01

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

  10. 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.

  11. 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.

  12. An Experimental Field Dataset with Buoyant, Neutral, and Dense Gas Atmospheric Releases and Model Comparisons in Low-Wind Speed (Diffusion) Conditions

    SciTech Connect

    Veronica E. Wannberg, Gustavious Williams, Patrick Sawyer, and Richard Venedam

    2010-09-01

    Aunique field dataset from a series of low–wind speed experiments, modeling efforts using three commonly used models to replicate these releases, and statistical analysis of how well these models were able to predict the plume concentrations is presented. The experiment was designed to generate a dataset to describe the behavior of gaseous plumes under low-wind conditions and the ability of current, commonly used models to predict these movements. The dataset documents the release and transport of three gases: ammonia (buoyant), ethylene (neutral), and propylene (dense) in low–wind speed (diffusion) conditions. Release rates ranged from 1 to 20 kg h21. Ammonia and ethylene had five 5-min releases each to represent puff releases and five 20-min releases each to represent plume releases. Propylene had five 5-min puffs, six 20-min plumes, and a single 30-min plume. Thirty-two separate releases ranging from 6 to 47 min were conducted, of which only 30 releases generated useful data. The data collected included release rates, atmospheric concentrations to 100 m from the release point, and local meteorological conditions. The diagnostics included nine meteorological stations on 100-m centers and 36 photoionization detectors in a radial pattern. Three current stateof- the-practice models, Aerial locations of Hazardous Atmospheres (ALOHA), Emergency Prediction Information code (EPIcode), and Second-Order Closure Integrated Puff (SCIPUFF), were used to try to duplicate the measured field results. Low wind speeds are difficult to model, and all of the models had difficulty replicating the field measurements. However, the work does show that these models, if used correctly, are conservative (overpredict concentrations) and can be used for safety and emergency planning.

  13. On the suitability of gelatin as a laboratory-scale analogue for host rock to study the propagation of buoyant liquid-filled fractures in geophysical applications, notably magmatic dikes

    NASA Astrophysics Data System (ADS)

    Tait, S.; Taisne, B.; Craster, R.; Bhat, H.

    2012-12-01

    Experimental modelling of the propagation of magma-filled fractures or dikes has relied heavily on the use of gelatin as a host solid because of several convenient properties, notably its low elastic shear modulus, as well as the properties of transparency and photo-elasticity. The first of these properties notably allows gelatin to deform under its own weight at laboratory scale. Quite a wide range of fluids have been used in order to study the propagation of cracks filled particularly with (positively or negatively) buoyant fluid, the case of buoyant cracks being believed particularly important for geologic applications. Fluids that have been used include air, various oils, alkanes, and mercury as well as some aqueous solutions, which raises the question of the action of surface energy between hydrophobic fluids and hydrophilic gelatin. One important discrepancy between experimental results and theory is that many experimental cracks filled with a constant volume of buoyant fluid have been observed to propagate at constant velocity whereas theory predicts that they should lengthen proportional to time^(1/3). Physical analysis and numerical calculations on this problem indeed suggest that it may be explained qualitatively by a surface energy effect, however, numerical values for the physical parameters involved indicate that the velocity predicted for viscous flow driven by surface energy between gelatin and different fluids is not that at which the fractures propagate. We review the experimental literature, and show that existing physical models for fissure propagation do not give a very satisfactory quantitative explanation of the fissure velocities observed. One source of discrepancy may be that theories are most commonly limited to 2-dimensional treatments whereas experimental fractures are naturally 3-dimensional. We also revisit the question of whether host solid fracture processes or rheologic variations, which have generally been thought to be unimportant in determining the velocity of fissures in the geologic context, may also be a source of discrepancy in the experimental data.

  14. 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...

  15. 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.

  16. Measuring W from neutrally buoyant drifting floats

    NASA Astrophysics Data System (ADS)

    Gascard, J.-C.; Lherminier, P.

    2003-04-01

    Merging with the concept of the so-called Swallow float, initiated by John Swallow half a century ago to observe water mass horizontal displacements from a lagrangian point of view, a Vertical Current Meter (VCM) was developped during the early 70s by A. Voorhis, H. Stommel and D. Webb at WHOI, for measuring, in situ, the vertical component of the velocity in the Ocean. Although the first VCMs were intended to detect strong vertical currents (up to 10 cm/s) related to deep ocean convection, VCMs have also been used since then for measuring vertical velocities in a very broad range as far as current intensity and frequency are concerned, which makes the VCM a very unique instrument. We will present some of the most relevant results obtained with VCMs over the past 30 years dealing with internal waves, tides and ageostrophic currents as well as non hydrostatic movements generated in unstable thick mixed layers.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 1Preliminary Instability in a buoyant chemical

    E-print Network

    Treibergs, Andrejs

    that the combusion is curvature sensitve so that the normal velocity of a flame front is increased if the flame effects, pressure and gravity and combustion effects at the interface through the burning speed of a flame. In order to observe buouyancy effects in premixed gas flames, Abid and Romney [1] have experimented

  2. Buoyant melting instabilities beneath extending lithosphere

    E-print Network

    Tackley, Paul J.

    of a retained fraction of partial melt, and depletion of the solid by melt extraction. We find a critical of melt and changes in composition and phase abundance in the residual solid rock. Thus if one portion find that solid depletion buoyancy can either stabilize or destabilize a partially melting layer

  3. Experimental investigation of a stratified buoyant wake 

    E-print Network

    Kraft, Wayne Neal

    2004-11-15

    layer / wake interactions, and qualitative observations of the behavior have been made. Also, quantitative measurements of velocity fluctuations and density fluctuations in the near wake have been obtained using particle image velocimetry (PIV) and a...

  4. Two-link swimming using buoyant orientation

    E-print Network

    Burton, Lisa Janelle

    The scallop theorem posits that a two-link system immersed in a fluid at low Reynolds number cannot achieve any net translation via cyclic changes in its hinge angle. Here, we propose an approach to “breaking” this theorem, ...

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

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... buoyancy tube. (14) Drop test. The drop test required under paragraph 1/5.1 of IMO Resolution A.689(17) and... the container. (15) Loading and seating test. For the loading and seating test required under... be not less than 200 mm (8 in.). (16) Cold-inflation test. The cold-inflation test required...

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

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... buoyancy tube. (14) Drop test. The drop test required under paragraph 1/5.1 of IMO Resolution A.689(17) and... the container. (15) Loading and seating test. For the loading and seating test required under... be not less than 200 mm (8 in.). (16) Cold-inflation test. The cold-inflation test required...

  7. Study of a non-buoyant diffusion flame radiative characteristics 

    E-print Network

    Legros, Guillaume

    2003-12-09

    This study is a contribution to a project aiming to characterize a fire spreading in weightlessness. An ethylene burner across which an air flow leads to boundary layer type conditions is used. First experimental results ...

  8. 46 CFR 160.010-3 - Inflatable buoyant apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...reversible apparatus are equipped with drains; (iv) Sponge. One sponge as described in § 160.151-21(d) on each apparatus with a capacity of less than 25 persons, or two sponges on each apparatus with a capacity of 25 or more...

  9. 46 CFR 160.010-3 - Inflatable buoyant apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...reversible apparatus are equipped with drains; (iv) Sponge. One sponge as described in § 160.151-21(d) on each apparatus with a capacity of less than 25 persons, or two sponges on each apparatus with a capacity of 25 or more...

  10. 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.

  11. MEASUREMENT OF BUOYANT JET ENTRAINMENT FROM SINGLE AND MULTIPLE SOURCES

    EPA Science Inventory

    An experimental investigation was conducted to determine the dilution characteristics of single and multiple discharges typical of modern natural and mechanical draft cooling towers. Simultaneous measurements of velocity and tracer concentration profiles were taken at various dow...

  12. 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%.

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

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...) One or more exterior canopy lamps meeting the requirements of 46 CFR 160.151-15(n) must be provided... reversible apparatus are equipped with drains; (iv) Sponge. One sponge as described in § 160.151-21(d) on each apparatus with a capacity of less than 25 persons, or two sponges on each apparatus with...

  14. 46 CFR 160.010-3 - Inflatable buoyant apparatus.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) One or more exterior canopy lamps meeting the requirements of 46 CFR 160.151-15(n) must be provided... reversible apparatus are equipped with drains; (iv) Sponge. One sponge as described in § 160.151-21(d) on each apparatus with a capacity of less than 25 persons, or two sponges on each apparatus with...

  15. 46 CFR 160.010-3 - Inflatable buoyant apparatus.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) One or more exterior canopy lamps meeting the requirements of 46 CFR 160.151-15(n) must be provided... reversible apparatus are equipped with drains; (iv) Sponge. One sponge as described in § 160.151-21(d) on each apparatus with a capacity of less than 25 persons, or two sponges on each apparatus with...

  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. 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.

  18. 46 CFR 131.870 - Life floats and buoyant apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS Markings for Fire Equipment and Emergency Equipment § 131.870 Life floats...at least 38 millimeters (1-1/2 inches) high and in a color contrasting to that of the float or apparatus. This number...

  19. 46 CFR 131.870 - Life floats and buoyant apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS Markings for Fire Equipment and Emergency Equipment § 131.870 Life floats...at least 38 millimeters (1-1/2 inches) high and in a color contrasting to that of the float or apparatus. This number...

  20. 46 CFR 131.870 - Life floats and buoyant apparatus.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS Markings for Fire Equipment and Emergency Equipment § 131.870 Life floats...at least 38 millimeters (1-1/2 inches) high and in a color contrasting to that of the float or apparatus. This number...

  1. 46 CFR 131.870 - Life floats and buoyant apparatus.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS Markings for Fire Equipment and Emergency Equipment § 131.870 Life floats...at least 38 millimeters (1-1/2 inches) high and in a color contrasting to that of the float or apparatus. This number...

  2. 46 CFR 131.870 - Life floats and buoyant apparatus.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS Markings for Fire Equipment and Emergency Equipment § 131.870 Life floats...at least 38 millimeters (1-1/2 inches) high and in a color contrasting to that of the float or apparatus. This number...

  3. 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, ...

  4. Buoyant plumes with inertial and chemical reaction-driven forcing

    E-print Network

    Morris, Stephen W.

    power law relationship that explains their ascent velocity. However, the morphology of the plume heads flame balls, a phenomenon closely related to autocatalytic plumes, were also simulated. Flame balls were found to have three dynamical regimes. Below a critical radius, the smallest flame balls experi- enced

  5. Pneumatic raft automatically reforms after rupture of buoyant member

    NASA Technical Reports Server (NTRS)

    Radnofsky, M. I.; Shewmake, G. A.

    1968-01-01

    Unique, inflated, expandable socks are attached within the inflated chamber of a raft or a float in such a way that collapse of the chamber wall through damage, causes the adjacent sock to expand and restore the original configuration.

  6. Dispersion in two-dimensional turbulent buoyant plumes

    E-print Network

    Rocco, Stefano; Woods, Andrew W.

    2015-06-02

    -dimensional planar plumes and fountains. Journal of Fluid Mechanics 750, 210–244. Carazzo, G., Kaminski, E. & Tait, S. 2008 On the rise of turbulent plumes: Quantitative effects of variable entrainment for submarine hydrothermal vents, terrestrial and extra... or buoyancy are especially intriguing ( Turner 1979 and Carazzo et al. 2008 ), with applications for modelling volcanic plumes in the atmosphere, hydrothermal plumes in the ocean ( Woods 2010 ), effluent spreading in shallow estuaries and river outflows...

  7. 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.

  8. 46 CFR 122.730 - Servicing of inflatable liferafts, inflatable buoyant apparatus, inflatable life jackets, and...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... this chapter— (1) No later than the month and year on its servicing sticker affixed under 46 CFR 160... apparatus, inflatable life jackets, and inflated rescue boats. 122.730 Section 122.730 Shipping COAST GUARD..., inflatable life jackets, and inflated rescue boats. (a) An inflatable liferaft or inflatable...

  9. 46 CFR 122.730 - Servicing of inflatable liferafts, inflatable buoyant apparatus, inflatable life jackets, and...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... this chapter— (1) No later than the month and year on its servicing sticker affixed under 46 CFR 160... apparatus, inflatable life jackets, and inflated rescue boats. 122.730 Section 122.730 Shipping COAST GUARD..., inflatable life jackets, and inflated rescue boats. (a) An inflatable liferaft or inflatable...

  10. 46 CFR 122.730 - Servicing of inflatable liferafts, inflatable buoyant apparatus, inflatable life jackets, and...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... this chapter— (1) No later than the month and year on its servicing sticker affixed under 46 CFR 160... apparatus, inflatable life jackets, and inflated rescue boats. 122.730 Section 122.730 Shipping COAST GUARD..., inflatable life jackets, and inflated rescue boats. (a) An inflatable liferaft or inflatable...

  11. 46 CFR 122.730 - Servicing of inflatable liferafts, inflatable buoyant apparatus, inflatable life jackets, and...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... this chapter— (1) No later than the month and year on its servicing sticker affixed under 46 CFR 160... apparatus, inflatable life jackets, and inflated rescue boats. 122.730 Section 122.730 Shipping COAST GUARD..., inflatable life jackets, and inflated rescue boats. (a) An inflatable liferaft or inflatable...

  12. 46 CFR 122.730 - Servicing of inflatable liferafts, inflatable buoyant apparatus, inflatable life jackets, and...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... this chapter— (1) No later than the month and year on its servicing sticker affixed under 46 CFR 160... apparatus, inflatable life jackets, and inflated rescue boats. 122.730 Section 122.730 Shipping COAST GUARD..., inflatable life jackets, and inflated rescue boats. (a) An inflatable liferaft or inflatable...

  13. 46 CFR 117.137 - Stowage of life floats and buoyant apparatus.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...certified to be resistant to deterioration from ultraviolent light; and (3) If metal, be corrosion resistant. ...type certified to be resistant to deterioration from ultraviolet light. (e) If the vessel carries more than the one...

  14. 46 CFR 117.137 - Stowage of life floats and buoyant apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...certified to be resistant to deterioration from ultraviolent light; and (3) If metal, be corrosion resistant. ...type certified to be resistant to deterioration from ultraviolet light. (e) If the vessel carries more than the one...

  15. 46 CFR 180.137 - Stowage of life floats and buoyant apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...type certified to be resistant to deterioration from ultraviolet light; and (3) If metal, be corrosion resistant...type certified to be resistant to deterioration from ultraviolet light. (e) If the vessel carries more than one...

  16. 46 CFR 180.137 - Stowage of life floats and buoyant apparatus.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...type certified to be resistant to deterioration from ultraviolet light; and (3) If metal, be corrosion resistant...type certified to be resistant to deterioration from ultraviolet light. (e) If the vessel carries more than one...

  17. 46 CFR 117.137 - Stowage of life floats and buoyant apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...certified to be resistant to deterioration from ultraviolent light; and (3) If metal, be corrosion resistant. ...type certified to be resistant to deterioration from ultraviolet light. (e) If the vessel carries more than the one...

  18. 46 CFR 180.137 - Stowage of life floats and buoyant apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...type certified to be resistant to deterioration from ultraviolet light; and (3) If metal, be corrosion resistant...type certified to be resistant to deterioration from ultraviolet light. (e) If the vessel carries more than one...

  19. 46 CFR 180.137 - Stowage of life floats and buoyant apparatus.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...type certified to be resistant to deterioration from ultraviolet light; and (3) If metal, be corrosion resistant...type certified to be resistant to deterioration from ultraviolet light. (e) If the vessel carries more than one...

  20. 46 CFR 180.137 - Stowage of life floats and buoyant apparatus.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...type certified to be resistant to deterioration from ultraviolet light; and (3) If metal, be corrosion resistant...type certified to be resistant to deterioration from ultraviolet light. (e) If the vessel carries more than one...

  1. 46 CFR 117.137 - Stowage of life floats and buoyant apparatus.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...certified to be resistant to deterioration from ultraviolent light; and (3) If metal, be corrosion resistant. ...type certified to be resistant to deterioration from ultraviolet light. (e) If the vessel carries more than the one...

  2. 46 CFR 117.137 - Stowage of life floats and buoyant apparatus.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...certified to be resistant to deterioration from ultraviolent light; and (3) If metal, be corrosion resistant. ...type certified to be resistant to deterioration from ultraviolet light. (e) If the vessel carries more than the one...

  3. Particle separation by Stokes number for small neutrally buoyant spheres in a fluid

    E-print Network

    Phanindra Tallapragada; Shane. D. Ross

    2008-03-12

    It is a commonly observed phenomenon that spherical particles with inertia in an incompressible fluid do not behave as ideal tracers. Due to the inertia of the particle, the dynamics are described in a four dimensional phase space and thus can differ considerably from the ideal tracer dynamics. Using finite time Lyapunov exponents we compute the sensitivity of the final position of a particle with respect to its initial velocity, relative to the fluid and thus partition the relative velocity subspace at each point in configuration space. The computations are done at every point in the relative velocity subspace, thus giving a sensitivity field. The Stokes number being a measure of the independence of the particle from the underlying fluid flow, acts as a parameter in determining the variation in these partitions. We demonstrate how this partition framework can be used to segregate particles by Stokes number in a fluid. The fluid model used for demonstration is a two dimensional cellular flow.

  4. Large eddy simulation of turbulent buoyant flow in a confined cavity with conjugate heat transfer

    NASA Astrophysics Data System (ADS)

    Cintolesi, C.; Petronio, A.; Armenio, V.

    2015-09-01

    Turbulent natural convection in enclosure is a paradigmatic case for wide class of processes of great interest for industrial and environmental problems. The solid-fluid thermal interaction, the anisotropy of the turbulence intensity in the flow field along with the transient nature of heat transfer processes, pose challenges regarding the numerical modeling. The case of a square cavity with differently heated vertical walls and two horizontal conductive plates is studied at Ra = 1.58 × 109. The study is carried out numerically, using large-eddy simulation together with a dynamic Lagrangian turbulence model and a conjugate heat transfer method to take into account heat transfer at the solid surfaces. First, validation is carried out against the literature experimental and numerical data. The results of validation tests evidence the limitations of using the adiabatic conditions as a model for reproducing an insulator. In fact, the adiabatic condition represents the asymptotic behavior which is often difficult to reach in real conditions. Successively, the model is used to investigate the effect on the flow field of different materials composing the horizontal walls. Initial conditions representative of physical experiment are used. In order to reduce the computational time required for a simulation with insulating materials at the walls, a four-step temperature advancement strategy is proposed, based on the artificial reduction-first and recover-later of the specific heat coefficient Cp of the materials at different stages of the simulation. The conductivity of the solid media is found to influence the flow configuration since heat transfer at the solid walls substantially modifies the turbulent field and makes the flow field less homogeneous along the horizontal direction.

  5. Buoyant Convection Heat Transfer of the Liquid LiPb Flow with a Transverse Magnetic Field

    NASA Astrophysics Data System (ADS)

    Wang, H. Y.; Zhang, X. D.; Ding, K. K.

    2010-03-01

    The nature convection of the liquid LiPb, due to thermal diffusion, in the poloidal channel adjacent to the First Wall (FW) perpendicular to the strong magnetic field of the blanket has been considered and studied. The cubic enclosure filled by the liquid metal LiPb flow is assumed as the analyzed model. It was numerical simulated by three-dimensional CFD with special MHD code. The Hartmann number is from 20 to 200. The wall of the enclosure was heated by a uniform temperature and the other wall was cooled along two opposite vertical walls, all other walls being adiabatic. The momentum equation and electrical-magnetic equations for the liquid LiPb flow in the enclosure have given. It is assumed the nature convection be steady-state conditions. The velocity and temperature of the LiPb flow with differential Hartmann number is discussed. The temperature distribution is changed due to magnetic field.There is a strong thermal coupling, modifying importantly the magnitude of the flow. The effect of the buoyancy on pressure driven duct flows has been investigated.

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

    SciTech Connect

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

    1995-02-01

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

  7. 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...

  8. 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.

  9. Radiative Heating and the Buoyant Rise of Magnetic Flux Tubes in the Solar interior

    NASA Astrophysics Data System (ADS)

    Fan, Y.; Fisher, G. H.

    1996-06-01

    We study the effect of radiative heating on the evolution of thin magnetic flux tubes in the solar interior and on the eruption of magnetic flux loops to the surface. Magnetic flux tubes experience radiative heating because (1) the mean temperature gradient in the lower convection zone and the overshoot region deviates substantially from that of radiative equilibrium, and hence there is a non-zero divergence of radiative heat flux; and (2) the magnetic pressure of the flux tube causes a small change of the thermodynamic properties within the tube relative to the surrounding field-free fluid, resulting in an additional divergence of radiative heat flux. Our calculations show that the former constitutes the dominant source of radiative heating experienced by the flux tube. In the overshoot region, the radiative heating is found to cause a quasi-static rising of the toroidal flux tubes with an upward drift velocity ˜ 10-3|?| cm s-1, where ? ? ?e - ?ad < 0 describes the subadiabaticity in the overshoot layer. The upward drift velocity does not depend sensitively on the field strength of the flux tubes. Thus in order to store toroidal flux tubes in the overshoot region for a period comparable to the length of the solar cycle, the magnitude of the subadiabaticity ?(< 0) in the overshoot region must be as large as ˜ 3 × 10-4. We discuss the possibilities for increasing the magnitude of ? and for reducing the rate of radiative heating of the flux tubes in the overshoot region. Using numerical simulations we study the formation of ‘?’-shaped emerging loops from toroidal flux tubes in the overshoot region as a result of radiative heating. The initial toroidal tube is assumed to be non-uniform in its thermodynamic properties along the tube and lies at varying depths beneath the base of the convection zone. The tube is initially in a state of neutral buoyancy with the internal density of the tube plasma equal to the local external density. We find from our numerical simulations that such a toroidal tube rises quasi-statically due to radiative heating. The top portion of the nonuniform tube first enters the convection zone and may be brought to an unstable configuration which eventually leads to the eruption of an anchored flux loop to the surface. Assuming reasonable initial parameters, our numerical calculations yield fairly short rise times (2 4 months) for the development of the emerging flux loops. This suggests that radiative heating is an effective way of causing the eruption of magnetic flux loops, leading to the formation of active regions at the surface.

  10. 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...

  11. 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.

  12. Second order turbulence simulation of the rotating, buoyant, recirculating convection in the Czochralski crystal melt. Thesis

    NASA Technical Reports Server (NTRS)

    Ristorcelli, J. R.

    1992-01-01

    The topics are presented in viewgraph form and include: (1) a problem statement; (2) the rapid pressure models tested (both linear and nonlinear); (3) the computational problem; and (4) shortcomings and future work.

  13. 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…

  14. Two-link swimming using buoyant orientation L. J. Burton,1,a

    E-print Network

    Choset, Howie

    .1063/1.3481785 A growing interest in natural and artificial microswim- ming has led to a variety of recent studies by using temporally and/or spatially varying magnetic fields to actuate or pull a passive swimmer,4 posing- ported by a new model incorporating low Reynolds number fluid dynamics with locomotion analysis

  15. 46 CFR 131.865 - Inflatable liferafts and inflatable buoyant apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

  16. 46 CFR 131.865 - Inflatable liferafts and inflatable buoyant apparatus.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

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

  17. 46 CFR 131.865 - Inflatable liferafts and inflatable buoyant apparatus.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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

  18. 46 CFR 131.865 - Inflatable liferafts and inflatable buoyant apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  19. 46 CFR 131.865 - Inflatable liferafts and inflatable buoyant apparatus.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

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

    E-print Network

    California at Berkeley, University of

    of the National Optical Astronomy Observa- tories operated by the Association of Universities for Research of radiative heating. The initial toroidal tube is assumed to be non-uniform in its thermodynamic properties. Moreno-Insertis, Schussler, & Ferris-Mas (1992) and Ferris-Mas & Schussler (1994) have argued

  1. Academically Buoyant Students Are Less Anxious about and Perform Better in High-Stakes Examinations

    ERIC Educational Resources Information Center

    Putwain, David W.; Daly, Anthony L.; Chamberlain, Suzanne; Sadreddini, Shireen

    2015-01-01

    Background: Prior research has shown that test anxiety is negatively related to academic buoyancy, but it is not known whether test anxiety is an antecedent or outcome of academic buoyancy. Furthermore, it is not known whether academic buoyancy is related to performance on high-stakes examinations. Aims: To test a model specifying reciprocal…

  2. Elasto-buoyant heavy spheres: a unique way to test non-linear elasticity

    E-print Network

    Aditi Chakrabarti; Manoj K. Chaudhury; Serge Mora; Yves Pomeau

    2015-09-16

    Extra-large deformations produced by a heavy bead gently deposited on the horizontal surface of an incompressible ultra-soft elastic medium are investigated, providing a basis for a better understanding of highly strained elastic materials. These experiments stipulate a scaling law for the penetration depth of the bead inside the gel, $\\delta~\\sim a^{3/2}$, $a$ being the radius of the bead, which is in quantitative agreement with an original asymptotic analytic model developed in this article. This model highlights the role of buoyancy and the effects of the strong non-linearities coming from the large deformations.

  3. 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.

  4. Displacement forces on a neutral current detector from a buoyant and flexible cable under tension

    SciTech Connect

    Walston, S.

    1994-05-01

    As a means for maintaining order in the 112 NCD readout cables, it is proposed to put the cables under tension in such a way that they lie as straight as possible and rest along the top surface of the acrylic D{sub 2}O vessel. However, one aim is to avoid using top anchor points to secure the NCDs in the D{sub 2}O vessel, but rather to just let the counter`s inherent buoyancy maintain the necessary vertical orientation. As a result, applying a tension to the readout cable may pull the counters too far off of vertical. Whether or not the counter is pulled too far off of vertical depends in large part on the characteristics of the cable, i.e. modulus of elasticity and initial radius of curvature. Given that the applied tension in equilibrium is just equal to the restoring force on the counter when pulled off of vertical by some arbitrarily small amount, and given that the final radius of curvature of the readout cable is 6 meters (the radius of the D{sub 2}O vessel), what then must the modulus of elasticity be for a given initial radius of curvature of the cable? This assumes that the cable will be wrapped around a spool or somehow coiled for shipment. This also assumes that upon delivery of the cables, some effort can be made to straighten them out somewhat. For this approximation, the buoyancy of the cables is assumed to be negligible. The small length of cable that does not rest against the inner surface of the D{sub 2}O vessel is also neglected.

  5. Influence of Buoyant Convection on the Stability of Enclosed Laminar Flames

    NASA Technical Reports Server (NTRS)

    Brooker, John E.; Jia, Kezhong; Stocker, Dennis P.; Chen, Lea-Der

    1999-01-01

    An investigation of the stability limits of Enclosed Laminar Flames (ELF) was conducted in the Middeck Glovebox (MGBX) facility on the STS-87 Space Shuttle mission (November to December 1997). The primary objective of the ELF glovebox investigation is to determine the effect of buoyancy on the stability of round, laminar, gas-jet diffusion flames in a co-flow air duct. Comparison tests were conducted in normal gravity to allow isolation and identification of the influence of buoyancy. The results were used to map the lift-off and blow-out stability limits as a function of the fuel and air velocities for the two buoyancy conditions. Approximately 50 tests were conducted during the Space Shuttle mission, using a 50/50 mixture (volume basis) of methane and nitrogen as the fuel. The experimental results verified the hypothesis that substantially greater velocities are required to destabilize the flame in microgravity. The increase in air velocity required to induce lift off in microgravity (compared to normal gravity) was nearly equal to the increase required to induce blow out. Furthermore, the air velocity increase was relatively independent of the fuel flow, except at low fuel flows. At high fuel flows, it was found that the microgravity flames tend to immediately blow out after lift off. This is in agreement with the free-jet theory which suggests that stable lifted flames are not possible for fuels with a Schmidt number of 0.5

  6. Buoyant production and consumption of turbulence kinetic energy in cloud-topped mixed layers

    NASA Technical Reports Server (NTRS)

    Randall, D. A.

    1984-01-01

    It is pointed out that studies of the entraining planetary boundary layer (PBL) have generally emphasized the role of buoyancy fluxes in driving entrainment. The buoyancy flux is proportional to the rate of conversion of the potential energy of the mean flow into the kinetic energy of the turbulence. It is not unusual for conversion to proceed in both directions simultaneously. This occurs, for instance, in both clear and cloudy convective mixed layers which are capped by inversions. A partitioning of the net conversion into positive parts, generating turbulence kinetic energy (TKE), and negative parts (TKE-consuming), would make it possible to include the positive part in the gross production rate, and closure would be achieved. Three different approaches to partitioning have been proposed. The present investigation is concerned with a comparison of the three partitioning theories. Particular attention is given to the cloud-topped mixed layer because in this case the differences between two partitioning approaches are most apparent.

  7. 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.

  8. 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

  9. Plume Rise and Dispersion of Emissions from Low Level Buoyant Sources in Urban Areas

    E-print Network

    Pournazeri, Sam

    2012-01-01

    Air pollution mainly from vehicles, industries, and power plants,Air pollution mainly from vehicles, industries, and power plants,air pollution can be even more destructive than the radiation in the exclusion zone around the Chernobyl power plant

  10. Penetration of a negatively buoyant jet in a miscible liquid P. Philippe,a

    E-print Network

    Godoy-Diana, Ramiro

    case where buoyancy is opposed to the injection flow. This arises in numerous industrial processes or natural flows such as refu- eling compensated fuel tanks on naval vessels,2,3 waste dis- posal systems, ventilation of large buildings,4 or motion of plumes and clouds in the atmosphere.5 In most

  11. CFD Simulations of Erosion of a Stratified Layer by a Buoyant Jet in a Large Vessel 

    E-print Network

    Sarikurt, Fatih Sinan

    2015-04-29

    accident, the leaked hydrogen from the primary circuit can form a stable stratified layer at the top of the containment building. The formation and erosion of a stratified layer is a challenging numerical problem due to the interaction mechanism of the jet...

  12. Three-Dimensional Recomposition of the Absorption Field Inside a Non-Buoyant Sooting Diffusion Flame 

    E-print Network

    Legros, Guillaume; Fuentes, Andres; Ben-Abdallah, Philippe; Baillargeat, Jacques; Joulain, Pierre; Vantelon, Jean-Pierre; Torero, Jose L

    A remote scanning retrieval method was developed to investigate the soot layer produced by a laminar diffusion flame established over a flat plate burner in microgravity. Experiments were conducted during parabolic flights. ...

  13. 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.

  14. 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

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

    USGS Publications Warehouse

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

    1997-01-01

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

  16. Pressure drop and heat transfer characteristics of nearly neutrally buoyant particulate slurry for advanced energy transmission fluids

    NASA Astrophysics Data System (ADS)

    Liu, K. V.; Choi, U. S.; Kasza, K. E.

    1988-12-01

    Under sponsorship of the U.S. Department of Energy, Argonne National Laboratory (ANL) is developing high-performance energy transmission fluids that have the potential to substantially reduce frictional losses and improve heat transfer in a variety of thermal systems, allowing the use of smaller piping, pumps, heat exchangers, and storage tanks. This paper presents experimental results and discusses the pressure drop and heat transfer characteristics of non-melting slurry flows. The experimental data obtained in this study improve the fundamental understanding of slurry fluid mechanics and heat transfer, and provide support for the use of slurries as advanced energy transmission fluids in thermal system applications.

  17. 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

  18. 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

    ... tested for weathering. The Coast Guard will determine which one or more of the following tests will be... minutes of completion of the weathering test required by paragraph (b)(1) of this section, the...

  19. 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

    ... tested for weathering. The Coast Guard will determine which one or more of the following tests will be... minutes of completion of the weathering test required by paragraph (b)(1) of this section, the...

  20. 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

    ... tested for weathering. The Coast Guard will determine which one or more of the following tests will be... minutes of completion of the weathering test required by paragraph (b)(1) of this section, the...

  1. 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

    ... tested for weathering. The Coast Guard will determine which one or more of the following tests will be... minutes of completion of the weathering test required by paragraph (b)(1) of this section, the...

  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, 2011 CFR

    2011-10-01

    ... tested for weathering. The Coast Guard will determine which one or more of the following tests will be... minutes of completion of the weathering test required by paragraph (b)(1) of this section, the...

  3. Two vertical forces affect objects that are immersed in fluid: the force of gravity and the buoyant force. The force of gravity

    E-print Network

    Bowen, W. Don

    aquatic species, physiological mechanisms or 2323The Journal of Experimental Biology 203, 2323­2330 (2000 changes in buoyancy, which in turn may influence diving behaviour. We examined the longitudinal changes in buoyancy and diving behaviour of 14 adult grey seals (Halichoerus grypus) during two periods that represent

  4. 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.

  5. Non-hydrostatic modeling of cohesive sediment transport associated with a subglacial buoyant jet in glacial fjords: A process-oriented approach

    E-print Network

    in glacial fjords: A process-oriented approach Julio Salcedo-Castro a, , Daniel Bourgault b,1 , Samuel J Buoyancy Non hydrostatic model Sediment dynamics Fjord a b s t r a c t Fine sediment transport produced of these glacimarine environments are glacial fjords (ice fields or glaciers in the hinterland), characterized by high

  6. 46 CFR 160.060-8 - Marking.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...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...

  7. 46 CFR 160.049-4 - Construction and workmanship.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam... box type filled with unicellular plastic foam buoyant material. Such cushions consist essentially of...

  8. 46 CFR 160.049-4 - Construction and workmanship.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam... box type filled with unicellular plastic foam buoyant material. Such cushions consist essentially of...

  9. 46 CFR 199.45 - Tests and inspections of lifesaving equipment and arrangements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... such as lifebuoys, lifejackets, immersion suits, work vests, lifefloats, buoyant apparatus, and..., immersion suits, work vests, lifefloats, buoyant apparatus, and associated equipment; (4) The...

  10. 46 CFR 199.45 - Tests and inspections of lifesaving equipment and arrangements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... such as lifebuoys, lifejackets, immersion suits, work vests, lifefloats, buoyant apparatus, and..., immersion suits, work vests, lifefloats, buoyant apparatus, and associated equipment; (4) The...

  11. 46 CFR 199.45 - Tests and inspections of lifesaving equipment and arrangements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... such as lifebuoys, lifejackets, immersion suits, work vests, lifefloats, buoyant apparatus, and..., immersion suits, work vests, lifefloats, buoyant apparatus, and associated equipment; (4) The...

  12. 46 CFR 199.45 - Tests and inspections of lifesaving equipment and arrangements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... such as lifebuoys, lifejackets, immersion suits, work vests, lifefloats, buoyant apparatus, and..., immersion suits, work vests, lifefloats, buoyant apparatus, and associated equipment; (4) The...

  13. 46 CFR 199.45 - Tests and inspections of lifesaving equipment and arrangements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... such as lifebuoys, lifejackets, immersion suits, work vests, lifefloats, buoyant apparatus, and..., immersion suits, work vests, lifefloats, buoyant apparatus, and associated equipment; (4) The...

  14. 46 CFR 160.049-7 - Procedure for approval.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-7... be granted separately to each manufacturer for each unicellular plastic foam buoyant cushion...

  15. 46 CFR 160.049-7 - Procedure for approval.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-7... be granted separately to each manufacturer for each unicellular plastic foam buoyant cushion...

  16. 46 CFR 131.540 - Operational readiness.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., rescue boat, life float, or buoyant apparatus must be in good working order and ready for immediate use... lifeboat, liferaft, survival craft, rescue boat, life float, or buoyant apparatus is stowed, launched,...

  17. 46 CFR 180.15 - Applicability to existing vessels.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) Each inflatable liferaft, inflatable buoyant apparatus, life float, and buoyant apparatus on the vessel... float-free and activate; (3) Was manufactured on or after October 1, 1988; and (4) Was installed on...

  18. 46 CFR 180.15 - Applicability to existing vessels.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... lazarette. (d) Each inflatable liferaft, inflatable buoyant apparatus, life float, and buoyant apparatus on... float-free and activate; (3) Was manufactured on or after October 1, 1988; and (4) Was installed on...

  19. 46 CFR 131.540 - Operational readiness.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., rescue boat, life float, or buoyant apparatus must be in good working order and ready for immediate use... lifeboat, liferaft, survival craft, rescue boat, life float, or buoyant apparatus is stowed, launched,...

  20. 46 CFR 131.540 - Operational readiness.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., rescue boat, life float, or buoyant apparatus must be in good working order and ready for immediate use... lifeboat, liferaft, survival craft, rescue boat, life float, or buoyant apparatus is stowed, launched,...

  1. 46 CFR 131.540 - Operational readiness.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., rescue boat, life float, or buoyant apparatus must be in good working order and ready for immediate use... lifeboat, liferaft, survival craft, rescue boat, life float, or buoyant apparatus is stowed, launched,...

  2. 46 CFR 131.540 - Operational readiness.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., rescue boat, life float, or buoyant apparatus must be in good working order and ready for immediate use... lifeboat, liferaft, survival craft, rescue boat, life float, or buoyant apparatus is stowed, launched,...

  3. 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...

  4. 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:...

  5. 46 CFR 160.060-1 - Incorporation by reference.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...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)...

  6. 33 CFR 175.23 - Serviceable condition.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...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...

  7. 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...

  8. 46 CFR 160.064-2 - Types and models.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Types and models. (a) Types. Water safety buoyant devices covered...subpart shall be of two general types, viz, those intended to...thrown. (b) Models. Water safety buoyant devices may be of different models which...

  9. 46 CFR 160.048-2 - Types and sizes.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...LIFESAVING EQUIPMENT Specification for a Buoyant Cushion, Fibrous Glass § 160.048-2 Types and sizes. (a) Types. ...Buoyant cushions shall have not less than 225 square inches top surface area; widths and lengths which fall within the...

  10. 46 CFR 160.052-1 - Incorporation by reference.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 46 CFR 160.049-1 - Incorporation by reference.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...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...

  17. 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...

  18. 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...

  19. 46 CFR 160.049-1 - Incorporation by reference.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...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...

  20. 46 CFR 160.010-2 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 6 2014-10-01 2014-10-01 false Definitions. 160.010-2 Section 160.010-2 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Buoyant Apparatus for Merchant Vessels § 160.010-2 Definitions. Buoyant apparatus. Buoyant apparatus...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 18 CFR 415.31 - Prohibited uses.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...pesticides, domestic or industrial waste, radioactive materials, petroleum products...equipment or of buoyant materials, except for purposes...pesticides, domestic or industrial waste, radioactive materials, petroleum...

  7. 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

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

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-1... Guard specifications: 160.055—Life Preservers, Unicellular Plastic Foam, Adult and Child. 164.015—Plastic Foam, Unicellular, Buoyant, Sheet and Molded Shapes. (4) Military specifications....

  9. 46 CFR 160.049-1 - Incorporation by reference.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-1... Guard specifications: 160.055—Life Preservers, Unicellular Plastic Foam, Adult and Child. 164.015—Plastic Foam, Unicellular, Buoyant, Sheet and Molded Shapes. (4) Military specifications....

  10. 46 CFR 160.052-7 - Inspections and tests-standard and nonstandard vests. 1

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...The buoyant inserts from adult size buoyant vests shall provide not...the inserts from child medium size vests shall provide not less...the inserts from child small size vests shall provide not less than 7 pounds buoyancy. (f) Body strap test. The...

  11. 46 CFR 160.052-7 - Inspections and tests-standard and nonstandard vests. 1

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...The buoyant inserts from adult size buoyant vests shall provide not...the inserts from child medium size vests shall provide not less...the inserts from child small size vests shall provide not less than 7 pounds buoyancy. (f) Body strap test. The...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  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, 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...

  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, 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...

  2. Preparation of Genomic DNA from Hawaiian Bobtail Squid (Euprymna scolopes) Tissue by Cesium Chloride Gradient

    E-print Network

    Ruby, Edward G.

    -made stock solution to avoid the dangers of handling solid ethidium bromide. Isoamyl alcohol, water by gradient centrifugation is an established method based on the specific buoyant density of double also be adapted to the purification of RNA, which has a higher buoyant density than DNA. Unfortunately

  3. 46 CFR 160.010-9 - Procedure for approval.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 6 2014-10-01 2014-10-01 false Procedure for approval. 160.010-9 Section 160.010-9 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Buoyant Apparatus for Merchant Vessels § 160.010-9 Procedure for approval. (a) A buoyant...

  4. 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...

  5. 46 CFR 169.556 - Work vests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Work vests. 169.556 Section 169.556 Shipping COAST GUARD... Firefighting Equipment Additional Lifesaving Equipment § 169.556 Work vests. (a) Buoyant work vests carried.... (b) Approved buoyant work vests are items of safety apparel and may be carried aboard vessels to...

  6. 46 CFR 169.556 - Work vests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Work vests. 169.556 Section 169.556 Shipping COAST GUARD... Firefighting Equipment Additional Lifesaving Equipment § 169.556 Work vests. (a) Buoyant work vests carried.... (b) Approved buoyant work vests are items of safety apparel and may be carried aboard vessels to...

  7. 46 CFR 169.556 - Work vests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Work vests. 169.556 Section 169.556 Shipping COAST GUARD... Firefighting Equipment Additional Lifesaving Equipment § 169.556 Work vests. (a) Buoyant work vests carried.... (b) Approved buoyant work vests are items of safety apparel and may be carried aboard vessels to...

  8. 46 CFR 169.556 - Work vests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Work vests. 169.556 Section 169.556 Shipping COAST GUARD... Firefighting Equipment Additional Lifesaving Equipment § 169.556 Work vests. (a) Buoyant work vests carried.... (b) Approved buoyant work vests are items of safety apparel and may be carried aboard vessels to...

  9. 46 CFR 169.556 - Work vests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Work vests. 169.556 Section 169.556 Shipping COAST GUARD... Firefighting Equipment Additional Lifesaving Equipment § 169.556 Work vests. (a) Buoyant work vests carried.... (b) Approved buoyant work vests are items of safety apparel and may be carried aboard vessels to...

  10. 46 CFR 160.064-3 - Requirements. 1

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... (a) General. Every water safety buoyant device...Designs and constructions. Water safety buoyant devices...slightly backward position in the water to as great a degree as is...wearer face downward in the water. Devices intended to be...device has been submerged in fresh water for 24 or more...

  11. 46 CFR 25.25-5 - Life preservers and other lifesaving equipment required.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 160 of this chapter (see 46 CFR chapter I, revised as of October 1, 1979), which may be used as long... substitute an immersion suit for a life preserver, buoyant vest, or marine buoyant device required under paragraphs (b) or (c) of this section. Each immersion suit carried in accordance with this paragraph must...

  12. 46 CFR 25.25-5 - Life preservers and other lifesaving equipment required.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 160 of this chapter (see 46 CFR chapter I, revised as of October 1, 1979), which may be used as long... substitute an immersion suit for a life preserver, buoyant vest, or marine buoyant device required under paragraphs (b) or (c) of this section. Each immersion suit carried in accordance with this paragraph must...

  13. 46 CFR 25.25-5 - Life preservers and other lifesaving equipment required.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 160 of this chapter (see 46 CFR chapter I, revised as of October 1, 1979), which may be used as long... substitute an immersion suit for a life preserver, buoyant vest, or marine buoyant device required under paragraphs (b) or (c) of this section. Each immersion suit carried in accordance with this paragraph must...

  14. 46 CFR 25.25-5 - Life preservers and other lifesaving equipment required.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 160 of this chapter (see 46 CFR chapter I, revised as of October 1, 1979), which may be used as long... substitute an immersion suit for a life preserver, buoyant vest, or marine buoyant device required under paragraphs (b) or (c) of this section. Each immersion suit carried in accordance with this paragraph must...

  15. 46 CFR 117.202 - Survival craft-vessels operating on oceans routes.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... accommodations certificated to operate on an oceans route in warm water must be provided with inflatable buoyant... oceans route in warm water must be provided with either: (i) Inflatable buoyant apparatus of an aggregate... to operate on an oceans route in cold water must be provided with inflatable liferafts of...

  16. 46 CFR 160.048-1 - Incorporation by reference.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion, Fibrous Glass § 160.048-1... documents: (1) Military 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, form a part...

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

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion, Fibrous Glass § 160.048-1... documents: (1) Military 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, form a part...

  18. The water entry of decelerating spheres Jeffrey M. Aristoff,1

    E-print Network

    Bush, John W.M.

    The water entry of decelerating spheres Jeffrey M. Aristoff,1 Tadd T. Truscott,2 Alexandra H-density spheres on a water surface. Particular attention is given to characterizing the sphere dynamics to rationalize the form of water-entry cavities resulting from the impact of buoyant and nearly buoyant spheres

  19. 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...

  20. 46 CFR 160.048-1 - Incorporation by reference.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...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,...

  1. 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,...

  2. 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...

  3. 46 CFR 160.047-4 - Construction.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Specification for a Buoyant Vest, Kapok or Fibrous Glass, Adult and Child § 160.047-4 Construction...50 10.00 7.00 (3) Fibrous glass-filled pads for Models AF-1, CFM-1...buoyant vests shall be filled with fibrous glass distributed as provided in Table...

  4. 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...

  5. 46 CFR 160.047-4 - Construction.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Specification for a Buoyant Vest, Kapok or Fibrous Glass, Adult and Child § 160.047-4 Construction...50 10.00 7.00 (3) Fibrous glass-filled pads for Models AF-1, CFM-1...buoyant vests shall be filled with fibrous glass distributed as provided in Table...

  6. 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...

  7. 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...

  8. 46 CFR 160.047-4 - Construction.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Specification for a Buoyant Vest, Kapok or Fibrous Glass, Adult and Child § 160.047-4 Construction...50 10.00 7.00 (3) Fibrous glass-filled pads for Models AF-1, CFM-1...buoyant vests shall be filled with fibrous glass distributed as provided in Table...

  9. 46 CFR 160.056-2 - Construction.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... construction shall be such as is accepted as good engineering practice in the case of the specific material... = Volume of buoyant material required in cubic feet. W = Weight of equipped boat, in pounds. d = Specific gravity of hull material. c = Density of buoyant material, in pounds per cubic foot....

  10. 46 CFR 160.056-2 - Construction.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... construction shall be such as is accepted as good engineering practice in the case of the specific material... = Volume of buoyant material required in cubic feet. W = Weight of equipped boat, in pounds. d = Specific gravity of hull material. c = Density of buoyant material, in pounds per cubic foot....

  11. 46 CFR 160.056-2 - Construction.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... construction shall be such as is accepted as good engineering practice in the case of the specific material... = Volume of buoyant material required in cubic feet. W = Weight of equipped boat, in pounds. d = Specific gravity of hull material. c = Density of buoyant material, in pounds per cubic foot....

  12. 46 CFR 160.056-2 - Construction.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... construction shall be such as is accepted as good engineering practice in the case of the specific material... = Volume of buoyant material required in cubic feet. W = Weight of equipped boat, in pounds. d = Specific gravity of hull material. c = Density of buoyant material, in pounds per cubic foot....

  13. 46 CFR 160.056-2 - Construction.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... construction shall be such as is accepted as good engineering practice in the case of the specific material... = Volume of buoyant material required in cubic feet. W = Weight of equipped boat, in pounds. d = Specific gravity of hull material. c = Density of buoyant material, in pounds per cubic foot....

  14. 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.

  15. Steady advance of stem cell therapies: report from the 2011 World Stem Cell Summit, Pasadena, California, October 3-5.

    PubMed

    Swan, Melanie

    2011-12-01

    Stem cell research and related therapies (including regenerative medicine and cellular therapies) could have a significant near-term impact on worldwide public health and aging. One reason is the industry's strong linkage between policy, science, industry, and patient advocacy, as was clear in the attendance and programming at the 7(th) annual World Stem Cell Summit held in Pasadena, California, October 3-5, 2011. A special conference session sponsored by the SENS Foundation discussed how stem cell therapies are being used to extend healthy life span. Stem cells are useful not only in cell-replacement therapies, but also in disease modeling, drug discovery, and drug toxicity screening. Stem cell therapies are currently being applied to over 50 diseases, including heart, lung, neurodegenerative, and eye disease, cancer, and human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS). Dozens of companies are developing therapeutic solutions that are in different stages of clinical use and clinical trials. Some high-profile therapies include Dendreon's Provenge for prostate cancer, Geron's first-ever embryonic stem cell trials for spinal cord injury, Fibrocell's laViv cellular therapy for wrinkles, and well-established commercial skin substitutes (Organogenesis' Apligraf and Advanced BioHealing's Dermagraft). Stem cell policy issues under consideration include medical tourism, standards for large-scale stem cell manufacturing, and lingering ethical debates over the use of embryonic stem cells. Contemporary stem cell science advances include a focus on techniques for the direct reprogramming of cells from one lineage to another without returning to pluripotency as an intermediary step, improved means of generating and characterizing induced pluripotent cells, and progress in approaches to neurodegenerative disease. PMID:22175514

  16. 46 CFR 164.015-2 - Types.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... APPROVAL MATERIALS Plastic Foam, Unicellular, Buoyant, Sheet and Molded Shape § 164.015-2 Types. (a..., polymer or copolymer plastic foam shall be of three types as follows: Type A—for life preservers,...

  17. 46 CFR 164.015-2 - Types.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... APPROVAL MATERIALS Plastic Foam, Unicellular, Buoyant, Sheet and Molded Shape § 164.015-2 Types. (a..., polymer or copolymer plastic foam shall be of three types as follows: Type A—for life preservers,...

  18. 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 ...

  19. From Rennell to Robots Professor Gwyn Griffiths

    E-print Network

    Griffiths, Gwyn

    Swallow FRS preparing a neutrally buoyant float #12;Modern Thermometers and Floats #12;Vision for Ocean Trials - in Empress Dock as an ROV Control via an umbilical cable from a chase boat Empress Dock May 1996

  20. 46 CFR 117.15 - Applicability to existing vessels.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ....150 of this part, inclusive. (c) Each inflatable liferaft, inflatable buoyant apparatus, life float... § 117.64 of this part, if the EPIRB: (1) Is operable; (2) Is installed to automatically float-free...

  1. 46 CFR 117.15 - Applicability to existing vessels.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ....150 of this part, inclusive. (c) Each inflatable liferaft, inflatable buoyant apparatus, life float... § 117.64 of this part, if the EPIRB: (1) Is operable; (2) Is installed to automatically float-free...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 46 CFR 160.073-5 - Certification.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...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...

  10. 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...

  11. 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...

  12. 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...

  13. 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 §...

  14. 46 CFR 160.060-7 - Inspections and tests-standard and nonstandard vests. 1

    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 § 160.060-7 Inspections and tests—standard and nonstandard vests. 1 1 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 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...

  17. 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 ...

  18. Modelling Marine Ecosystems Mick Follows

    E-print Network

    Follows, Mick

    ?What is the marine ecosystem? · Food webFood web · Focus onFocus on phytoplanktonphytoplankton Bacteria, archaea #12, aggregating. Efficient export of organic carbon Small, buoyant, locally recycled. Inefficient export

  19. EXPERIMENTAL SIMULATION OF SINGLE AND MULTIPLE CELL COOLING TOWER PLUMES

    EPA Science Inventory

    An experimental investigation was conducted to determine the dilution characteristics of single and multiple port buoyant discharges typical of modern natural and mechanical draft cooling towers. Simultaneous measurements of velocity and tracer concentration profiles were taken a...

  20. 46 CFR 160.048-3 - Materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...for a Buoyant Cushion, Fibrous Glass § 160.048-3 Materials...properly processed. (c) Fibrous glass. The fibrous glass shall comply with the requirements...The welting where used may be any fiber or plastic material suitable...

  1. 46 CFR 160.048-3 - Materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...for a Buoyant Cushion, Fibrous Glass § 160.048-3 Materials...properly processed. (c) Fibrous glass. The fibrous glass shall comply with the requirements...The welting where used may be any fiber or plastic material suitable...

  2. 46 CFR 160.048-3 - Materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...for a Buoyant Cushion, Fibrous Glass § 160.048-3 Materials...properly processed. (c) Fibrous glass. The fibrous glass shall comply with the requirements...The welting where used may be any fiber or plastic material suitable...

  3. 76 FR 59391 - Notice of Availability of Government-Owned Inventions; Available for Licensing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-26

    .../2011//U.S. Patent No. 7,865,836: Geospatial Prioritized Data Acquisition Analysis and Presentation Issued 1/4/2011/ /U.S. Patent No. 7,868,833: An Ultra Wideband Buoyant Cable Antenna Element Issued...

  4. 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...

  5. 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 ...

  6. An Introduc+on to Langmuir Circula+on

    E-print Network

    Young, William R.

    in plasmas (now known as Langmuir Waves) · Invented the atomic hydrogen welding on 1917 paper on the chemistry of oil films · Atomic Physics: Helped to define neutrally buoyant with lightbulbs and weights -to measure below surface current 5

  7. 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.

  8. Carbon dioxide hydrate particles for ocean carbon sequestration

    E-print Network

    Chow, Aaron 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 ...

  9. Building and Environment 44 (2009) 216226 Effect of volumetric heat sources on hysteresis phenomena

    E-print Network

    Flynn, Morris R.

    2009-01-01

    severe. Unfortunately, the wind direction often exhibits diurnal or seasonal variations. A reversed of the internal buoyant convection. This effect has been examined for both distributed [3­6] and isolated [7

  10. 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...

  11. 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...

  12. 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 ...

  13. Quantifying the Consequences of the Ill-Defined Nature of Neutral Surfaces

    E-print Network

    Klocker, Andreas

    In the absence of diapycnal mixing processes, fluid parcels move in directions along which they do not encounter buoyant forces. These directions define the local neutral tangent plane. Because of the nonlinear nature of ...

  14. Syn-collisional delamination in convergent orogens: insights from lithospheric buoyancy and physical modeling 

    E-print Network

    Moore, Vernon Michael

    2002-01-01

    weak zone in the lithosphere near the Moho. A greater net negatively buoyant mass indicates a propensity for delamination to initiate in a passive margin versus an active margin during a subsequent collisional event. For delamination to initiate...

  15. 46 CFR 25.25-13 - Personal flotation device lights.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) Each immersion suit carried in accordance with § 25.25-5(e), each life preserver, each marine buoyant... section must be securely attached to the front shoulder area of the immersion suit, life preserver,...

  16. 46 CFR 25.25-13 - Personal flotation device lights.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...) Each immersion suit carried in accordance with § 25.25-5(e), each life preserver, each marine buoyant... section must be securely attached to the front shoulder area of the immersion suit, life preserver,...

  17. 46 CFR 25.25-13 - Personal flotation device lights.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) Each immersion suit carried in accordance with § 25.25-5(e), each life preserver, each marine buoyant... section must be securely attached to the front shoulder area of the immersion suit, life preserver,...

  18. Geochemistry: Rise of the continents

    NASA Astrophysics Data System (ADS)

    Lee, Cin-Ty A.; McKenzie, N. Ryan

    2015-07-01

    The continents are archives of Earth's evolution. Analysis of the isotopic signature of continental crust globally suggests that buoyant, silicic continents began to form 3 billion years ago, possibly linked to the onset of plate tectonics.

  19. 46 CFR 160.077-2 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...least one inflation chamber in combination with inherently buoyant material. (e) Inflation medium means any solid, liquid, or gas, that, when activated, provides inflation for buoyancy. (f) Inspector means an independent...

  20. 46 CFR 160.077-2 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...least one inflation chamber in combination with inherently buoyant material. (e) Inflation medium means any solid, liquid, or gas, that, when activated, provides inflation for buoyancy. (f) Inspector means an independent...

  1. 46 CFR 160.077-2 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...least one inflation chamber in combination with inherently buoyant material. (e) Inflation medium means any solid, liquid, or gas, that, when activated, provides inflation for buoyancy. (f) Inspector means an independent...

  2. 46 CFR 160.077-2 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...least one inflation chamber in combination with inherently buoyant material. (e) Inflation medium means any solid, liquid, or gas, that, when activated, provides inflation for buoyancy. (f) Inspector means an independent...

  3. 46 CFR 160.077-2 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...least one inflation chamber in combination with inherently buoyant material. (e) Inflation medium means any solid, liquid, or gas, that, when activated, provides inflation for buoyancy. (f) Inspector means an independent...

  4. 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...

  5. 46 CFR 164.019-3 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... component. PFD Type means the performance type designation as indicated in 33 CFR part 175 and this... (Buoyant Cushions). 4RB IV (Recreational Ring Buoys only). 5 Wearable Type V (intended use must...

  6. 46 CFR 164.019-3 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... component. PFD Type means the performance type designation as indicated in 33 CFR part 175 and this... (Buoyant Cushions). 4RB IV (Recreational Ring Buoys only). 5 Wearable Type V (intended use must...

  7. 46 CFR 164.019-3 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... component. PFD Type means the performance type designation as indicated in 33 CFR part 175 and this... (Buoyant Cushions). 4RB IV (Recreational Ring Buoys only). 5 Wearable Type V (intended use must...

  8. 46 CFR 160.010-7 - Methods of sampling, inspections and tests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... buoyant apparatus into still water from a height of 18 m (60 ft.) twice, once flat and once endwise. There... of length (15 lb. per foot) must be suspended in the water from the life lines along one of...

  9. 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...

  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. 46 CFR 160.005-4 - Construction.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. Structure of laboratory ball lightning.

    PubMed

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

    2009-12-01

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

  18. 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...

  19. 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...

  20. 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...

  1. 46 CFR 160.055-6 - Construction-nonstandard, life preservers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 46 CFR 160.055-5 - Construction-standard life preservers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...EQUIPMENT Life Preservers, Unicellular Plastic Foam, Adult and Child, for Merchant...preservers which essentially consist of plastic foam buoyant material arranged...constructed from one piece of unicellular plastic foam with neck hole and the body...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  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 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...

  18. 46 CFR 160.055-5 - Construction-standard life preservers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...EQUIPMENT Life Preservers, Unicellular Plastic Foam, Adult and Child, for Merchant...preservers which essentially consist of plastic foam buoyant material arranged...constructed from one piece of unicellular plastic foam with neck hole and the body...

  19. 46 CFR 160.055-5 - Construction-standard life preservers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...EQUIPMENT Life Preservers, Unicellular Plastic Foam, Adult and Child, for Merchant...preservers which essentially consist of plastic foam buoyant material arranged...constructed from one piece of unicellular plastic foam with neck hole and the body...

  20. 50 CFR 27.33 - Water skiing.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Guard approved ski belts, life jackets or buoyant vests. (e) Water skiing is prohibited within 300 feet of harbors, swimming beaches, and mooring areas, and within 100 feet of any designated swimming...

  1. 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.

  2. 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.

  3. 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.

  4. Nonlinear waves in a multilayer system

    NASA Astrophysics Data System (ADS)

    Simanovskii, Ilya B.; Viviani, Antonio; Dubois, Frank; Legros, Jean-Claude

    2009-02-01

    The joint action of buoyant and thermocapillary mechanisms of instability in a multilayer system, is investigated. The nonlinear convective regimes are studied by the finite difference method. The periodic boundary conditions on the lateral boundaries, are considered. It is found that the competition of both mechanisms of instability may lead to the appearance of a buoyant-thermocapillary traveling wave and a modulated traveling wave. To cite this article: I.B. Simanovskii et al., C. R. Mecanique 337 (2009).

  5. 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.

  6. 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.

  7. 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

  8. Are Brazil Nuts Attractive?

    NASA Astrophysics Data System (ADS)

    Sanders, Duncan A.; Swift, Michael R.; Bowley, R. M.; King, P. J.

    2004-11-01

    We present event-driven simulation results for single and multiple intruders in a vertically vibrated granular bed. Under our vibratory conditions, the mean vertical position of a single intruder is governed primarily by a buoyancylike effect. Multiple intruders also exhibit buoyancy governed behavior; however, multiple neutrally buoyant intruders cluster spontaneously and undergo horizontal segregation. These effects can be understood by considering the dynamics of two neutrally buoyant intruders. We have measured an attractive force between such intruders which has a range of five intruder diameters, and we provide a mechanistic explanation for the origins of this force.

  9. Analysis of the DNAs from seven varicella-zoster virus isolates.

    PubMed Central

    Richards, J C; Hyman, R W; Rapp, F

    1979-01-01

    The 32P-labeled DNAs from seven different clinical isolates of human varicella-zoster virus (VZV) were independently digested with five site-specific restriction endonucleases, EcoRI, HindIII, SmaI, BamHI, and AvaI. The digestion products were analyzed by electrophoresis on 0.5% agarose gels followed by autoradiography of the dried gels. Evaluation of the restriction enzyme cleavage patterns revealed small variations among the VZV DNAs. The VZV DNAs were also compared based on their buoyant densities in CsCl. No significant buoyant density differences were detected among the VZV DNAs. Images PMID:229268

  10. 46 CFR 160.049-3 - Materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-3... requirements of subpart 164.019. (b) Unicellular plastic foam. The unicellular plastic foam shall be all new... fiber or plastic material suitable for the purpose....

  11. 46 CFR 160.049-5 - Inspections and tests. 1

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-5 Inspections and tests. 1 1 The manufacturer of a personal flotation device must meet 33 CFR 181.701 through 33 CFR 181.705 which require an instruction pamphlet for each device that is sold or offered for sale...

  12. 46 CFR 160.049-5 - Inspections and tests. 1

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-5 Inspections and tests. 1 1 The manufacturer of a personal flotation device must meet 33 CFR 181.701 through 33 CFR 181.705 which require an instruction pamphlet for each device that is sold or offered for sale...

  13. 46 CFR 160.049-2 - Types and sizes.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 6 2014-10-01 2014-10-01 false Types and sizes. 160.049-2 Section 160.049-2 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam §...

  14. 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 Molded Shape § 164.015-3 Material and workmanship. (a) The unicellular plastic foam shall be all new material complying with the... values within the limits shown in Table 164.015-4(a). (b) The unicellular plastic foam shall be...

  15. 46 CFR 160.049-8 - Recognized laboratory.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 6 2013-10-01 2013-10-01 false Recognized laboratory. 160.049-8 Section 160.049-8 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam §...

  16. 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 Molded Shape § 164.015-5 Procedure for acceptance. (a) Unicellular plastic foam is not subject to formal approval, but will be... unicellular plastic foam prior to being incorporated into finished products, or during the course...

  17. 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 Molded Shape § 164.015-3 Material and workmanship. (a) The unicellular plastic foam shall be all new material complying with the... values within the limits shown in Table 164.015-4(a). (b) The unicellular plastic foam shall be...

  18. 46 CFR 160.049-3 - Materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam § 160.049-3... requirements of subpart 164.019. (b) Unicellular plastic foam. The unicellular plastic foam shall be all new... fiber or plastic material suitable for the purpose....

  19. 46 CFR 160.049-8 - Recognized laboratory.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 6 2014-10-01 2014-10-01 false Recognized laboratory. 160.049-8 Section 160.049-8 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam §...

  20. 46 CFR 160.049-6 - Marking.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 6 2014-10-01 2014-10-01 false Marking. 160.049-6 Section 160.049-6 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam §...

  1. 46 CFR 160.049-2 - Types and sizes.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 6 2013-10-01 2013-10-01 false Types and sizes. 160.049-2 Section 160.049-2 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam §...

  2. 46 CFR 26.30-1 - Approved unicellular plastic foam work vests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Approved unicellular plastic foam work vests. 26.30-1 Section 26.30-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS OPERATIONS Work Vest § 26.30-1 Approved unicellular plastic foam work vests. (a) Buoyant work vests carried under...

  3. 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 Molded Shape § 164.015-5 Procedure for acceptance. (a) Unicellular plastic foam is not subject to formal approval, but will be... unicellular plastic foam prior to being incorporated into finished products, or during the course...

  4. 46 CFR 26.30-1 - Approved unicellular plastic foam work vests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Approved unicellular plastic foam work vests. 26.30-1 Section 26.30-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS OPERATIONS Work Vest § 26.30-1 Approved unicellular plastic foam work vests. (a) Buoyant work vests carried under...

  5. 46 CFR 26.30-1 - Approved unicellular plastic foam work vests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Approved unicellular plastic foam work vests. 26.30-1 Section 26.30-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS OPERATIONS Work Vest § 26.30-1 Approved unicellular plastic foam work vests. (a) Buoyant work vests carried under...

  6. 46 CFR 160.049-6 - Marking.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 6 2013-10-01 2013-10-01 false Marking. 160.049-6 Section 160.049-6 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Specification for a Buoyant Cushion Plastic Foam §...

  7. The Birth of TCJ: Father's Curiosity Launched Paul Boyer on His Journey into Indian Country

    ERIC Educational Resources Information Center

    Hernandez, Juan Avila

    2009-01-01

    From its inception in 1988, the "Tribal College Journal" (TCJ) has been a family affair. Paul Boyer, the buoyant founder of the TCJ who published, produced, and edited the magazine until 1995, says the magazine sprouted not from an idealistic plan but from a combination of his own youthful enthusiasm; the support and guidance of his late father,…

  8. Dr. von Braun Tries Out the Neutral Buoyancy Simulator (NBS)

    NASA Technical Reports Server (NTRS)

    1967-01-01

    Marshall Space Flight Center (MSFC) Director, Dr. von Braun, is shown leaving the suiting-up van wearing a pressure suit prepared for a tryout in the MSFC Neutral Buoyancy Simulator (NBS). Weighted to a neutrally buoyant condition, Dr. von Braun was able to perform tasks underwater which simulated weightless conditions found in space.

  9. Dr. von Braun Tries Out the Neutral Buoyancy Simulator (NBS)

    NASA Technical Reports Server (NTRS)

    1967-01-01

    Astronaut L. Gordon Cooper checks the neck ring of a space suit worn by Marshall Space Flight Center (MSFC) Director, Dr. von Braun before he submerges into the water of the MSFC Neutral Buoyancy Simulator (NBS). Wearing a pressurized suit and weighted to a neutrally buoyant condition, Dr. von Braun was able to perform tasks underwater which simulated weightless conditions found in space.

  10. Dr. von Braun Tries Out the Neutral Buoyancy Simulator (NBS)

    NASA Technical Reports Server (NTRS)

    1967-01-01

    Marshall Space Flight Center (MSFC) Director, Dr. von Braun, submerges after spending some time under water in the MSFC Neutral Buoyancy Simulator (NBS). Weighted to a neutrally buoyant condition, Dr. von Braun was able to perform tasks underwater which simulated weightless conditions found in space.

  11. Dr. von Braun Tries Out the NBS

    NASA Technical Reports Server (NTRS)

    1967-01-01

    Marshall Space Flight Center (MSFC) Director, Dr. von Braun, is shown fitted with suit and diving equipment as he prepares for a tryout in the MSFC Neutral Buoyancy Simulator (NBS). Weighted to a neutrally buoyant condition, Dr. von Braun was able to perform tasks underwater which simulated weightless conditions found in space.

  12. 46 CFR 160.010-7 - Methods of sampling, inspections and tests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... apparatus tested for approval must be subjected to the drop test. Buoyant apparatus tested for production lot inspections must also be subjected to the drop test except that in the case of peripheral body type apparatus, the beam loading test may be substituted. (1) Drop test. Drop the complete...

  13. Zooplankton Community Metabolic Requirements and the Effect on Particle

    E-print Network

    Buesseler, Ken

    zone, calculate respiration rate Compare zooplankton C demand to loss of C with depth Neutrally Buoyant excretion respiration detritivory Base of euphotic egestion fragmentation excretion respiration (death) xx20 + O2 CO2 + H respiration #12;Zooplankton vertical biomass profiles OHA K2 Deployment 1 Deployment

  14. 46 CFR 160.047-3 - Materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... (f) Tie tapes and body strap loops. The tie tapes and body strap loops for an adult or child size buoyant vest specified...straps. The complete body strap assembly, including...150 pounds for an adult size and 115 pounds for a...

  15. 46 CFR 160.047-4 - Construction.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...comfortable fit to the bodies of various size wearers. (b) Envelope...Sheets 2 and 3 for child sizes, and sewed with...for both adult and child size buoyant vests. They...section H-H. (e) Body strap, hardware,...

  16. 46 CFR 160.055-5 - Construction-standard life preservers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...proper adjustment and fit to the bodies of various size wearers. (b) Construction...055-1A, Sheet 1, for adult size and Sheet 2 for child size. The reinforcing fabric shall be cemented on the foam buoyant body before coating. (2)...

  17. 46 CFR 160.055-5 - Construction-standard life preservers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...proper adjustment and fit to the bodies of various size wearers. (b) Construction...055-1A, Sheet 1, for adult size and Sheet 2 for child size. The reinforcing fabric shall be cemented on the foam buoyant body before coating. (2)...

  18. 46 CFR 160.047-4 - Construction.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...comfortable fit to the bodies of various size wearers. (b) Envelope...Sheets 2 and 3 for child sizes, and sewed with...for both adult and child size buoyant vests. They...section H-H. (e) Body strap, hardware,...

  19. 46 CFR 160.047-3 - Materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... (f) Tie tapes and body strap loops. The tie tapes and body strap loops for an adult or child size buoyant vest specified...straps. The complete body strap assembly, including...150 pounds for an adult size and 115 pounds for a...

  20. 46 CFR 180.200 - Survival craft-general.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... and flotation in 33 CFR part 183, and must meet the stowage, launching, and equipment requirements in... substituted for inflatable buoyant apparatus or life floats required under this section; (2) For a life float... route. (b) If the vessel carries a small boat or boats, the capacity of these boats may be...