Results for “Bubble chambers”

Universal probe, which contains a unique frequency discriminator, measures the static and dynamic levels of cryogenic liquids in a hydrogen bubble chamber. The probe allows boiling conditions or other turbulence to be observed throughout all the transition stages.

Dinkel, J. A.↗

NASA NTRS1970

Development of superconductive magnets

Survey of superconductive magnets considers - stabilization problems, advances in materials and their uses, and design evolution. Uses of superconducting magnets in particle accelerators and bubble chambers, as well as possible applications in magnetohydrodynamic and thermonuclear power generation and levitation are discussed.

Laurence, J. C.↗

NASA NTRS1985

Scattering and stopping of hadrons in nuclear matter

It was observed, in the 180 litre xenon bubble chamber, that when hadrons with kinetic energy higher than the pion production threshold fall on a layer of nuclear matter - on an atomic nucleus in other words - in many cases they can pass through it without causing particles production but they are deflected through some deflection angles; if the energy is lower than a few GeV and the nuclear matter layer is thick enough, the hadrons can be stopped in it. The amount of the deflection at a given incident hadron energy varies with the way the hadron strikes the atomic nucleus; the probability of the occurrence of stopping depends on the incident hadron identity and energy, and on the way the hadron passed through the nucleus, as well.

Strugalski, Z.↗

NASA NTRS1985

The effect of the relative nuclear size on the nucleus-nucleus interactions

The experimental data on the interactions of light nuclei (d, He(4), C(12)) at the momentum 4.2 GeV/cA with the carbon nuclei were taken in the 2-m propane bubble chamber. The distributions in the number of interacting nucleons, the spectra of protons, the mean energies of secondary pions and protons, the mean fractions of energy transferred to the pion and nucleon components are presented. The results of the investigation of the mechanism of nucleus-nucleus interactions can be used to calculate the nuclear cascades in the atmosphere.

Erofeeva, I. N.↗

NASA NTRS2006

Transient Flow Dynamics in Optical Micro Well Involving Gas Bubbles

The Lab-On-a-Chip Application Development (LOCAD) team at NASA s Marshall Space Flight Center is utilizing Lab-On-a-Chip to support technology development specifically for Space Exploration. In this paper, we investigate the transient two-phase flow patterns in an optic well configuration with an entrapped bubble through numerical simulation. Specifically, the filling processes of a liquid inside an expanded chamber that has bubbles entrapped. Due to the back flow created by channel expansion, the entrapped bubbles tend to stay stationary at the immediate downstream of the expansion. Due to the huge difference between the gas and liquid densities, mass conservation issues associated with numerical diffusion need to be specially addressed. The results are presented in terms of the movement of the bubble through the optic well. Bubble removal strategies are developed that involve only pressure gradients across the optic well. Results show that for the bubble to be moved through the well, pressure pulsations must be utilized in order to create pressure gradients across the bubble itself.

Johnson, B.↗

NASA NTRS2000

Quasi-Steady Acceleration Direction Indicator in Three Dimensions

Many materials processing and fluids physics experiments conducted in a microgravity environment require knowledge of the orientation of the low-frequency acceleration vector. This need becomes especially acute for space experiments such as directional solidification of a molten semiconductor, which is extremely sensitive to orientation and may involve tens of hours of operations of a materials furnace. These low-frequency acceleration data have been measured for many Shuttle missions with the Orbital Acceleration Research Experiment. Previous attempts at using fluid chambers for acceleration measurements have met with limited success due to pointing and vehicle attitude complications. An acceleration direction indicator is described, which is comprised of two orthogonal short cylinders of fluid, each with a small bubble. The motion and the position of the bubble within the chamber will indicate the direction of the acceleration experienced at the sensor location. The direction of the acceleration vector may then be calculated from these data. The frequency response of such an instrument may be tailored for particular experiments with the proper selection of fluid and gas parameters, surface type, and geometry. A three-dimensional system for sensing and displaying the low-frequency acceleration direction via an innovative technique described in this paper has advantages in terms of size, mass, and power compared with electronic instrumentation systems.

DeLombard, Richard↗

NASA NTRS2007

Method for nanoencapsulation of aerogels and nanoencapsulated aerogels produced by such method

A method for increasing the compressive modulus of aerogels comprising: providing aerogel substrate comprising a bubble matrix in a chamber; providing monomer to the chamber, the monomer comprising vapor phase monomer which polymerizes substantially free of polymerization byproducts; depositing monomer from the vapor phase onto the surface of the aerogel substrate under deposition conditions effective to produce a vapor pressure sufficient to cause the vapor phase monomer to penetrate into the bubble matrix and deposit onto the surface of the aerogel substrate, producing a substantially uniform monomer film; and, polymerizing the substantially uniform monomer film under polymerization conditions effective to produce polymer coated aerogel comprising a substantially uniform polymer coating substantially free of polymerization byproducts.Polymer coated aerogel comprising aerogel substrate comprising a substantially uniform polymer coating, said polymer coated aerogel comprising porosity and having a compressive modulus greater than the compressive modulus of the aerogel substrate, as measured by a 100 lb. load cell at 1 mm/minute in the linear range of 20% to 40% compression.

Sullivan, Thomas A.↗

NASA NTRS1990

Paving the way for space gardens

The Ecological Life Support System, a plant growth experiment now in its third year of closed chamber production at the NASA Kennedy Space Center, is discussed. Possible spin-off applications of hydrophonics experiments are noted. It is projected that long-term goals will include the integration of this garden system into the process of waste recycling for fertilization, air refreshment, and potable water recovery in a closed environment. The Biomass Production Chamber, a two-story bubble-shape steel biosphere modified from a Mercury/Gemini program attitude chamber provides a usable volume of 7.3 m x 3.6 m in diameter containing growing racks, piping for nutrient solutions, specialized lighting and sensors that provide information to the computers controlling the chamber and its functions. Computer programs provide highly sensitive monitoring and regulation of the system. Crops successfully harvested to date include dwarf wheat, lettuce, and soybeans.

Phillips, Patricia↗

NASA NTRS2004

Bubble Combustion

A method of energy production that is capable of low pollutant emissions is fundamental to one of the four pillars of NASA s Aeronautics Blueprint: Revolutionary Vehicles. Bubble combustion, a new engine technology currently being developed at Glenn Research Center promises to provide low emissions combustion in support of NASA s vision under the Emissions Element because it generates power, while minimizing the production of carbon dioxide (CO2) and nitrous oxides (NOx), both known to be Greenhouse gases. and allows the use of alternative fuels such as corn oil, low-grade fuels, and even used motor oil. Bubble combustion is analogous to the inverse of spray combustion: the difference between bubble and spray combustion is that spray combustion is spraying a liquid in to a gas to form droplets, whereas bubble combustion involves injecting a gas into a liquid to form gaseous bubbles. In bubble combustion, the process for the ignition of the bubbles takes place on a time scale of less than a nanosecond and begins with acoustic waves perturbing each bubble. This perturbation causes the local pressure to drop below the vapor pressure of the liquid thus producing cavitation in which the bubble diameter grows, and upon reversal of the oscillating pressure field, the bubble then collapses rapidly with the aid of the high surface tension forces acting on the wall of the bubble. The rapid and violent collapse causes the temperatures inside the bubbles to soar as a result of adiabatic heating. As the temperatures rise, the gaseous contents of the bubble ignite with the bubble itself serving as its own combustion chamber. After ignition, this is the time in the bubble s life cycle where power is generated, and CO2, and NOx among other species, are produced. However, the pollutants CO2 and NOx are absorbed into the surrounding liquid. The importance of bubble combustion is that it generates power using a simple and compact device. We conducted a parametric study using CAVCHEM, a computational model developed at Glenn, that simulates the cavitational collapse of a single bubble in a liquid (water) and the subsequent combustion of the gaseous contents inside the bubble. The model solves the time-dependent, compressible Navier-Stokes equations in one-dimension with finite-rate chemical kinetics using the CHEMKIN package. Specifically, parameters such as frequency, pressure, bubble radius, and the equivalence ratio were varied while examining their effect on the maximum temperature, radius, and chemical species. These studies indicate that the radius of the bubble is perhaps the most critical parameter governing bubble combustion dynamics and its efficiency. Based on the results of the parametric studies, we plan on conducting experiments to study the effect of ultrasonic perturbations on the bubble generation process with respect to the bubble radius and size distribution.

Corrigan, Jackie↗

NASA NTRS1984

Low-Density High-Strength Foamed Materials

Molten bubbles of metal or plastic coalesce into strong, lightweight materials that look like solidified foam. Bubbles formed in compartment that receives molten material and compressed gas that fills bubbles. Compartment has matrix of nozzles. Leaving nozzles, bubbles fall into acoustic chamber and coalesce; then drop through funnel and are cast into desired shape by extrusion or molding. Materials used for construction, extruded into molds, sawed, nailed, and generally handled as wood.

Wang, T.↗

NASA NTRS1984

Analysis of dynamic characteristics of fluid force induced by labyrinth seal

Flow patterns of the labyrinth seal are experimentally investigated for making a mathematical model of labyrinth seal and to obtain the flow induced force of the seal. First, the flow patterns in the labyrinth chamber are studied on the circumferential flow using bubble and on the cross section of the seal chamber using aluminum powder as tracers. And next, the fluid force and its phase angle are obtained from the measured pressure distribution in the chamber and the fluid force coefficients are derived from the fluid force and the phase angle. Those are similar to the expression of oil film coefficients. As a result, it is found that the vortices exist in the labyrinth chambers and its center moves up and down periodically. The pressure drop is biggest in the first stage of chambers and next in the last stage of chambers.

Iwatsubo, T.↗

NASA NTRS2010

Isolation of Resistance-Bearing Microorganisms

To better exploit the principles of gas transport and mass transport during the processes of cell seeding of 3D scaffolds and in vitro culture of 3D tissue engineered constructs, the oscillatory cell culture bioreactor provides a flow of cell suspensions and culture media directly through a porous 3D scaffold (during cell seeding) and a 3D construct (during subsequent cultivation) within a highly gas-permeable closed-loop tube. This design is simple, modular, and flexible, and its component parts are easy to assemble and operate, and are inexpensive. Chamber volume can be very low, but can be easily scaled up. This innovation is well suited to work with different biological specimens, particularly with cells having high oxygen requirements and/or shear sensitivity, and different scaffold structures and dimensions. The closed-loop changer is highly gas permeable to allow efficient gas exchange during the cell seeding/culturing process. A porous scaffold, which may be seeded with cells, is fixed by means of a scaffold holder to the chamber wall with scaffold/construct orientation with respect to the chamber determined by the geometry of the scaffold holder. A fluid, with/without biological specimens, is added to the chamber such that all, or most, of the air is displaced (i.e., with or without an enclosed air bubble). Motion is applied to the chamber within a controlled environment (e.g., oscillatory motion within a humidified 37 C incubator). Movement of the chamber induces relative motion of the scaffold/construct with respect to the fluid. In case the fluid is a cell suspension, cells will come into contact with the scaffold and eventually adhere to it. Alternatively, cells can be seeded on scaffolds by gel entrapment prior to bioreactor cultivation. Subsequently, the oscillatory cell culture bioreactor will provide efficient gas exchange (i.e., of oxygen and carbon dioxide, as required for viability of metabolically active cells) and controlled levels of fluid dynamic shear (i.e., as required for viability of shear-sensitive cells) to the developing engineered tissue construct. This bioreactor was recently utilized to show independent and interactive effects of a growth factor (IGF-I) and slow bidirectional perfusion on the survival, differentiation, and contractile performance of 3D tissue engineering cardiac constructs. The main application of this system is within the tissue engineering industry. The ideal final application is within the automated mass production of tissue- engineered constructs. Target industries could be both life sciences companies as well as bioreactor device producing companies.

Venkateswaran, Kasthuri, J.↗

NASA NTRS2010

Oscillating Cell Culture Bioreactor

To better exploit the principles of gas transport and mass transport during the processes of cell seeding of 3D scaffolds and in vitro culture of 3D tissue engineered constructs, the oscillatory cell culture bioreactor provides a flow of cell suspensions and culture media directly through a porous 3D scaffold (during cell seeding) and a 3D construct (during subsequent cultivation) within a highly gas-permeable closed-loop tube. This design is simple, modular, and flexible, and its component parts are easy to assemble and operate, and are inexpensive. Chamber volume can be very low, but can be easily scaled up. This innovation is well suited to work with different biological specimens, particularly with cells having high oxygen requirements and/or shear sensitivity, and different scaffold structures and dimensions. The closed-loop changer is highly gas permeable to allow efficient gas exchange during the cell seeding/culturing process. A porous scaffold, which may be seeded with cells, is fixed by means of a scaffold holder to the chamber wall with scaffold/construct orientation with respect to the chamber determined by the geometry of the scaffold holder. A fluid, with/without biological specimens, is added to the chamber such that all, or most, of the air is displaced (i.e., with or without an enclosed air bubble). Motion is applied to the chamber within a controlled environment (e.g., oscillatory motion within a humidified 37 C incubator). Movement of the chamber induces relative motion of the scaffold/construct with respect to the fluid. In case the fluid is a cell suspension, cells will come into contact with the scaffold and eventually adhere to it. Alternatively, cells can be seeded on scaffolds by gel entrapment prior to bioreactor cultivation. Subsequently, the oscillatory cell culture bioreactor will provide efficient gas exchange (i.e., of oxygen and carbon dioxide, as required for viability of metabolically active cells) and controlled levels of fluid dynamic shear (i.e., as required for viability of shear-sensitive cells) to the developing engineered tissue construct. This bioreactor was recently utilized to show independent and interactive effects of a growth factor (IGF-I) and slow bidirectional perfusion on the survival, differentiation, and contractile performance of 3D tissue engineering cardiac constructs. The main application of this system is within the tissue engineering industry. The ideal final application is within the automated mass production of tissue- engineered constructs. Target industries could be both life sciences companies as well as bioreactor device producing companies.

Freed, Lisa E.↗