High temperature adhesive silicone foam composition, foam generating system and method of generating foam. [For access denial

DOEpatents

Mead, J.W.; Montoya, O.J.; Rand, P.B.; Willan, V.O.

1983-12-21

Access to a space is impeded by generation of a sticky foam from a silicone polymer and a low boiling solvent such as a halogenated hydrocarbon. In a preferred aspect, the formulation is polydimethylsiloxane gel mixed with F502 Freon as a solvent and blowing agent, and pressurized with CO/sub 2/ in a vessel to about 250 PSI, whereby when the vessel is opened, a sticky and solvent resistant foam is deployed. The foam is deployable, over a wide range of temperatures, adhering to wet surfaces as well as dry, is stable over long periods of time and does not propagate flame or lose adhesive properties during an externally supported burn.

Space Shuttle Status News Conference

NASA Technical Reports Server (NTRS)

2005-01-01

Richard Gilbech, External Tank "Tiger Team" Lead, begins this space shuttle news conference with detailing the two major objectives of the team. The objectives include: 1) Finding the root cause of the foam loss on STS-114; and 2) Near and long term improvements for the external tank. Wayne Hale, Space Shuttle Program Manager, presents a chart to explain the external tank foam loss during STS-114. He gives a possible launch date for STS-121 after there has been a repair to the foam on the External Tank. He further discusses the changes that need to be made to the surrounding areas of the plant in New Orleans, due to Hurricane Katrina. Bill Gerstemaier, NASA Associate Administrator for Space Operations, elaborates on the testing of the external tank foam loss. The discussion ends with questions from the news media about a fix for the foam, replacement of the tiles, foam loss avoidance, the root cause of foam loss and a possible date for a new external tank to be shipped to NASA Kennedy Space Center.

Correlation between porosity and space holder content at different sintering temperatures of aluminum foam

NASA Astrophysics Data System (ADS)

Rushdi, N. M. F. M.; Jamaludin, S. B.; Mazlee, M. N.; Jamal, Z. A. Z.

2016-07-01

Aluminum foam is the most popular metal foam that can be used as energy absorbers, heat exchangers, air-oil separators and structure core of fuel cells. Melt-foaming agent, melt-gas injection, investment casting and powder-foaming agent techniques can be used to manufacture aluminum foam, but these techniques are too expensive. In this study, the aluminum foam was manufactured via a sintering dissolution process (SDP). Powders of aluminum and sodium chloride as space holder (25, 40, 50 wt. %) were mixed together to produce a homogeneous mixture. The mixture was compacted at 200 MPa followed by sintering at 500, 550 and 600˚C for 2 hours. A warm running water stream was used to dissolve the space holder that was embedded in the aluminum. The result showed that, the space holder content performed a significant role to control the total porosity to a value between 18 and 40%, and the porosity increased with increasing content of space holder and sintering temperature.

Characterization of Polyimide Foams for Ultra-Lightweight Space Structures

NASA Technical Reports Server (NTRS)

Meador, Michael (Technical Monitor); Hillman, Keithan; Veazie, David R.

2003-01-01

Ultra-lightweight materials have played a significant role in nearly every area of human activity ranging from magnetic tapes and artificial organs to atmospheric balloons and space inflatables. The application range of ultra-lightweight materials in past decades has expanded dramatically due to their unsurpassed efficiency in terms of low weight and high compliance properties. A new generation of ultra-lightweight materials involving advanced polymeric materials, such as TEEK (TM) polyimide foams, is beginning to emerge to produce novel performance from ultra-lightweight systems for space applications. As a result, they require that special conditions be fulfilled to ensure adequate structural performance, shape retention, and thermal stability. It is therefore important and essential to develop methodologies for predicting the complex properties of ultra-lightweight foams. To support NASA programs such as the Reusable Launch Vehicle (RLV), Clark Atlanta University, along with SORDAL, Inc., has initiated projects for commercial process development of polyimide foams for the proposed cryogenic tank integrated structure (see figure 1). Fabrication and characterization of high temperature, advanced aerospace-grade polyimide foams and filled foam sandwich composites for specified lifetimes in NASA space applications, as well as quantifying the lifetime of components, are immensely attractive goals. In order to improve the development, durability, safety, and life cycle performance of ultra-lightweight polymeric foams, test methods for the properties are constant concerns in terms of timeliness, reliability, and cost. A major challenge is to identify the mechanisms of failures (i.e., core failure, interfacial debonding, and crack development) that are reflected in the measured properties. The long-term goal of the this research is to develop the tools and capabilities necessary to successfully engineer ultra-lightweight polymeric foams. The desire is to reduce density at the material and structural levels, while at the same time maintaining or increasing mechanical and other properties.

Assessment of Technologies for the Space Shuttle External Tank Thermal Protection System and Recommendations for Technology Improvement. Part 1; Materials Characterization and Analysis

NASA Technical Reports Server (NTRS)

Weiser, Erik S.; SaintClair, Terry L.; Nemeth, Michael P.

2004-01-01

The use of foam insulation on the External Tank (ET) was necessitated by the potentially hazardous build up of ice on the vehicle prior to and during launch. This use of foam was initiated on the Saturn V rocket, which, like the Space Shuttle, used cryogenic fuel. Two major types of foam have been used on the ET. The first type is NCFI 24-124, an acreage material that is automatically sprayed on in a controlled environment. It replaced CPR 488 in 1998 and has been used since that time. The other major foams, BX-250 or BX-265, are handsprayed foams that are used to close out regions where the various sections of the ET are attached. The objectives of the present report are to study the chemistries of the various foam materials and to determine how physical and mechanical anomalies might occur during the spray and curing process. To accomplish these objectives, the report is organized as follows. First, the chemistries of the raw materials will be discussed. This will be followed by a discussion of how chemistry relates to void formation. Finally, a TGA-MS will be used to help understand the various foams and how they degrade with the evolution of chemical by-products.

Characterization of Space Shuttle Thermal Protection System (TPS) Materials for Return-to-Flight following the Shuttle Columbia Accident Investigation

NASA Technical Reports Server (NTRS)

Wingard, Doug

2006-01-01

During the Space Shuttle Columbia Accident Investigation, it was determined that a large chunk of polyurethane insulating foam (= 1.67 lbs) on the External Tank (ET) came loose during Columbia's ascent on 2-1-03. The foam piece struck some of the protective Reinforced Carbon-Carbon (RCC) panels on the leading edge of Columbia's left wing in the mid-wing area. This impact damaged Columbia to the extent that upon re-entry to Earth, superheGed air approaching 3,000 F caused the vehicle to break up, killing all seven astronauts on board. A paper after the Columbia Accident Investigation highlighted thermal analysis testing performed on External Tank TPS materials (1). These materials included BX-250 (now BX-265) rigid polyurethane foam and SLA-561 Super Lightweight Ablator (highly-filled silicone rubber). The large chunk of foam from Columbia originated fiom the left bipod ramp of the ET. The foam in this ramp area was hand-sprayed over the SLA material and various fittings, allowed to dry, and manually shaved into a ramp shape. In Return-to-Flight (RTF) efforts following Columbia, the decision was made to remove the foam in the bipod ramp areas. During RTF efforts, further thermal analysis testing was performed on BX-265 foam by DSC and DMA. Flat panels of foam about 2-in. thick were sprayed on ET tank material (aluminum alloys). The DSC testing showed that foam material very close to the metal substrate cured more slowly than bulk foam material. All of the foam used on the ET is considered fully cured about 21 days after it is sprayed. The RTF culminated in the successful launch of Space Shuttle Discovery on 7-26-05. Although the flight was a success, there was another serious incident of foam loss fiom the ET during Shuttle ascent. This time, a rather large chunk of BX-265 foam (= 0.9 lbs) came loose from the liquid hydrogen (LH2) PAL ramp, although the foam did not strike the Shuttle Orbiter containing the crew. DMA testing was performed on foam samples taken fiom a simulated PAL ramp panel. It was found that the smooth rind on the foam facing the cable tray did significantly affect the properties of foam at the PAL ramp surface. The smooth rind increased the storage modulus E' of the foam as much as 20- 40% over a temperature range of -145 to 95 C. Because of foam loss fiom the PAL ramp, future Shuttle flights were grounded indefinitely to allow further testing to better understand foam properties. The decision was also made to remove foam from the LH2 PAL, ramp. Other RTF efforts prior to the launch of Discovery included

Moduli stabilization in stringy ISS models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakayama, Yu; Nakayama, Yu; Yamazaki, Masahito

2007-09-28

We present a stringy realization of the ISS metastable SUSY breaking model with moduli stabilization. The mass moduli of the ISS model is stabilized by gauging of a U(1) symmetry and its D-term potential. The SUSY is broken both by F-terms and D-terms. It is possible to obtain de Sitter vacua with a vanishingly small cosmological constant by an appropriate fine-tuning of flux parameters.

Application of an Elongated Kelvin Model to Space Shuttle Foams

NASA Technical Reports Server (NTRS)

Sullivan, Roy M.; Ghosn, Louis J.; Lerch, Bradley A.

2009-01-01

The space shuttle foams are rigid closed-cell polyurethane foams. The two foams used most-extensively oil space shuttle external tank are BX-265 and NCFL4-124. Because of the foaming and rising process, the foam microstructures are elongated in the rise direction. As a result, these two foams exhibit a nonisotropic mechanical behavior. A detailed microstructural characterization of the two foams is presented. Key features of the foam cells are described and the average cell dimensions in the two foams are summarized. Experimental studies are also conducted to measure the room temperature mechanical response of the two foams in the two principal material directions (parallel to the rise and perpendicular to the rise). The measured elastic modulus, proportional limit stress, ultimate tensile strength, and Poisson's ratios are reported. The generalized elongated Kelvin foam model previously developed by the authors is reviewed and the equations which result from this model are summarized. Using the measured microstructural dimensions and the measured stiffness ratio, the foam tensile strength ratio and Poisson's ratios are predicted for both foams and are compared with the experimental data. The predicted tensile strength ratio is in close agreement with the measured strength ratio for both BX-265 and NCFI24-124. The comparison between the predicted Poisson's ratios and the measured values is not as favorable.

Determination of Acreage Thermal Protection Foam Loss From Ice and Foam Impacts

NASA Technical Reports Server (NTRS)

Carney, Kelly S.; Lawrence, Charles

2015-01-01

A parametric study was conducted to establish Thermal Protection System (TPS) loss from foam and ice impact conditions similar to what might occur on the Space Launch System. This study was based upon the large amount of testing and analysis that was conducted with both ice and foam debris impacts on TPS acreage foam for the Space Shuttle Project External Tank. Test verified material models and modeling techniques that resulted from Space Shuttle related testing were utilized for this parametric study. Parameters varied include projectile mass, impact velocity and impact angle (5 degree and 10 degree impacts). The amount of TPS acreage foam loss as a result of the various impact conditions is presented.

Space Shuttle Stiffener Ring Foam Failure Analysis, a Non-Conventional Approach

NASA Technical Reports Server (NTRS)

Howard, Philip M.

2015-01-01

The Space Shuttle Program made use of the excellent properties of rigid polyurethane foam for cryogenic tank insulation and as structural protection on the solid rocket boosters. When foam applications de-bond, classical methods of failure analysis did not provide root cause of the failure of the foam. Realizing that foam is the ideal media to document and preserve its own mode of failure, thin sectioning was seen as a logical approach for foam failure analysis to observe the three dimensional morphology of the foam cells. The cell foam morphology provided a much greater understanding of the failure modes than previously achieved.

D-foam-induced flavor condensates and breaking of supersymmetry in free Wess-Zumino fluids

NASA Astrophysics Data System (ADS)

Mavromatos, Nick E.; Sarkar, Sarben; Tarantino, Walter

2011-08-01

Recently [N. E. Mavromatos and S. Sarkar, New J. Phys. 10, 073009 (2008) NJOPFM1367-263010.1088/1367-2630/10/7/073009; N. E. Mavromatos, S. Sarkar, and W. Tarantino, Phys. Rev. DPRVDAQ1550-7998 80, 084046 (2009)10.1103/PhysRevD.80.084046], we argued that a particular model of string-inspired quantum space-time foam (D-foam) may induce oscillations and mixing among flavored particles. As a result, rather than the mass-eigenstate vacuum, the correct ground state to describe the underlying dynamics is the flavor vacuum, proposed some time ago by Blasone and Vitiello as a description of quantum field theories with mixing. At the microscopic level, the breaking of target-space supersymmetry is induced in our space-time foam model by the relative transverse motion of brane defects. Motivated by these results, we show that the flavor vacuum, introduced through an inequivalent representation of the canonical (anti-) commutation relations, provides a vehicle for the breaking of supersymmetry at a low-energy effective field-theory level; on considering the flavor-vacuum expectation value of the energy-momentum tensor and comparing with the form of a perfect relativistic fluid, it is found that the bosonic sector contributes as dark energy while the fermion contribution is like dust. This indicates a strong and novel breaking of supersymmetry, of a nonperturbative nature, which may characterize the low-energy field theory of certain quantum-gravity models.

Prospective of employing high porosity open-cell metal foams in passive cryogenic radiators for space applications

NASA Astrophysics Data System (ADS)

Tisha, Dixit; Indranil, Ghosh

2017-02-01

Passive cryogenic radiators work on the principle of dissipating heat to the outer space purely by radiation. High porosity open-cell metal foams are a relatively new class of extended surfaces. These possess the advantages of high surface area density and low weight, characteristics which the space industry looks for. In case of radiative heat transfer, the porous nature of metal foams permits a deeper penetration of the incident radiation. Consequently, the heat transfer area participating in radiative heat exchange increases thereby enhancing the heat transfer rate. However, effective heat conduction in between the foam struts reduces as a result of the void spaces. These two conflicting phenomenon for radiation heat transfer in metal foams have been studied in this work. Similar to the foam conduction-convection heat transfer analysis, a conduction-radiation heat transfer model has been developed for metal foams in analogy with the conventional solid fin theory. Metal foams have been theoretically represented as simple cubic structures. A comparison of the radiative heat transfer through metal foams and solid fins attached to a surface having constant temperature has been presented. Effect of changes in foam characteristic properties such as porosity and pore density have also been studied.

46 CFR 108.459 - Number and location of outlets.

Code of Federal Regulations, 2013 CFR

2013-10-01

... outlets. (a) A foam extinguishing system in a space must have enough outlets to spread a layer of foam of uniform thickness over the deck or bilge areas of the space. (b) A foam extinguishing system in a space that has a boiler on a flat that is open to or can drain into a lower portion of the space must have...

46 CFR 108.459 - Number and location of outlets.

Code of Federal Regulations, 2010 CFR

2010-10-01

... outlets. (a) A foam extinguishing system in a space must have enough outlets to spread a layer of foam of uniform thickness over the deck or bilge areas of the space. (b) A foam extinguishing system in a space that has a boiler on a flat that is open to or can drain into a lower portion of the space must have...

46 CFR 108.459 - Number and location of outlets.

Code of Federal Regulations, 2011 CFR

2011-10-01

... outlets. (a) A foam extinguishing system in a space must have enough outlets to spread a layer of foam of uniform thickness over the deck or bilge areas of the space. (b) A foam extinguishing system in a space that has a boiler on a flat that is open to or can drain into a lower portion of the space must have...

46 CFR 108.459 - Number and location of outlets.

Code of Federal Regulations, 2012 CFR

2012-10-01

... outlets. (a) A foam extinguishing system in a space must have enough outlets to spread a layer of foam of uniform thickness over the deck or bilge areas of the space. (b) A foam extinguishing system in a space that has a boiler on a flat that is open to or can drain into a lower portion of the space must have...

46 CFR 108.459 - Number and location of outlets.

Code of Federal Regulations, 2014 CFR

2014-10-01

... outlets. (a) A foam extinguishing system in a space must have enough outlets to spread a layer of foam of uniform thickness over the deck or bilge areas of the space. (b) A foam extinguishing system in a space that has a boiler on a flat that is open to or can drain into a lower portion of the space must have...

Geometric structures of super-(Diff(S/sup 1/)/S/sup 1/)*

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmidke, W.B.; Vokos, S.P.

Superconformal invariance is of central importance to a perturbative and non-perturbative formulation of stringy theory. The group that describes the invariances of the superstring is the super-Virasoro group, Super-Diff(S/sup 1/). The super-reparameterizations of the circle that leave a point fixed compose the quotient space Super-(Diff(S/sup 1/)/S/sup 1/). We investigate the holomorphic geometry of this infinite-dimensional Kaehler supermanifold and calculate its curvature. copyright 1989 Academic Press, Inc.

Discrete Space-Time: History and Recent Developments

NASA Astrophysics Data System (ADS)

Crouse, David

2017-01-01

Discussed in this work is the long history and debate of whether space and time are discrete or continuous. Starting from Zeno of Elea and progressing to Heisenberg and others, the issues with discrete space are discussed, including: Lorentz contraction (time dilation) of the ostensibly smallest spatial (temporal) interval, maintaining isotropy, violations of causality, and conservation of energy and momentum. It is shown that there are solutions to all these issues, such that discrete space is a viable model, yet the solution require strict non-absolute space (i.e., Mach's principle) and a re-analysis of the concept of measurement and the foundations of special relativity. In developing these solutions, the long forgotten but important debate between Albert Einstein and Henri Bergson concerning time will be discussed. Also discussed is the resolution to the Weyl tile argument against discrete space; however, the solution involves a modified version of the typical distance formula. One example effect of discrete space is then discussed, namely how it necessarily imposes order upon Wheeler's quantum foam, changing the foam into a gravity crystal and yielding crystalline properties of bandgaps, Brilluoin zones and negative inertial mass for astronomical bodies.

Monopropellant engine investigation for space shuttle reaction control system. Volume 3: Improvement of metal foam for catalyst retention

NASA Technical Reports Server (NTRS)

1975-01-01

The retention of granular catalyst in a metal foam matrix was demonstrated to greatly increase the life capability of hydrazine monopropellant reactors. Since nickel foam used in previous tests was found to become degraded after long-term exposure the cause of degradation was examined and metal foams of improved durability were developed. The most durable foam developed was a rhodium-coated nickel foam. An all-platinum foam was found to be incompatible in a hot ammonia (hydrazine) environment. It is recommended to scale up the manufacturing process for the improved foam to produce samples sufficiently large for space shuttle APU gas generator testing.

Space Shuttle Stiffener Ring Foam Failure, a Non-Conventional Approach

NASA Technical Reports Server (NTRS)

Howard, Philip M.

2007-01-01

The Space Shuttle makes use of the excellent properties of rigid polyurethane foam for cryogenic tank insulation and as structural protection on the solid rocket boosters. When foam applications debond, classical methods of analysis do not always provide root cause of the failure of the foam. Realizing that foam is the ideal media to document and preserve its own mode of failure, thin sectioning was seen as a logical approach for foam failure analysis. Thin sectioning in two directions, both horizontal and vertical to the application, was chosen to observe the three dimensional morphology of the foam cells. The cell foam morphology provided a much greater understanding of the failure modes than previously achieved.

Precision lattice test of the gauge/gravity duality at large N

DOE PAGES

Berkowitz, Evan; Rinaldi, Enrico; Hanada, Masanori; ...

2016-11-03

We perform a systematic, large-scale lattice simulation of D0-brane quantum mechanics. The large-N and continuum limits of the gauge theory are taken for the first time at various temperatures 0.4≤T≤1.0. As a way to test the gauge/gravity duality conjecture we compute the internal energy of the black hole as a function of the temperature directly from the gauge theory. We obtain a leading behavior that is compatible with the supergravity result E/N 2=7.41T 14/5: the coefficient is estimated to be 7.4±0.5 when the exponent is fixed and stringy corrections are included. This is the first confirmation of the supergravity predictionmore » for the internal energy of a black hole at finite temperature coming directly from the dual gauge theory. As a result, we also constrain stringy corrections to the internal energy.« less

46 CFR 108.469 - Quantity of foam producing materials.

Code of Federal Regulations, 2012 CFR

2012-10-01

... at least 5 minutes at each outlet; and (2) In a space must have enough foam producing material to... or space, the system need have only enough foam producing material to cover the largest space that the system covers or, if the liquid surface of a tank covered by the system is larger, the tank with...

46 CFR 108.469 - Quantity of foam producing materials.

Code of Federal Regulations, 2011 CFR

2011-10-01

... at least 5 minutes at each outlet; and (2) In a space must have enough foam producing material to... or space, the system need have only enough foam producing material to cover the largest space that the system covers or, if the liquid surface of a tank covered by the system is larger, the tank with...

46 CFR 108.469 - Quantity of foam producing materials.

Code of Federal Regulations, 2013 CFR

2013-10-01

... at least 5 minutes at each outlet; and (2) In a space must have enough foam producing material to... or space, the system need have only enough foam producing material to cover the largest space that the system covers or, if the liquid surface of a tank covered by the system is larger, the tank with...

46 CFR 108.469 - Quantity of foam producing materials.

Code of Federal Regulations, 2010 CFR

2010-10-01

... at least 5 minutes at each outlet; and (2) In a space must have enough foam producing material to... or space, the system need have only enough foam producing material to cover the largest space that the system covers or, if the liquid surface of a tank covered by the system is larger, the tank with...

46 CFR 108.469 - Quantity of foam producing materials.

Code of Federal Regulations, 2014 CFR

2014-10-01

... at least 5 minutes at each outlet; and (2) In a space must have enough foam producing material to... or space, the system need have only enough foam producing material to cover the largest space that the system covers or, if the liquid surface of a tank covered by the system is larger, the tank with...

A Mesh Refinement Study on the Impact Response of a Shuttle Leading-Edge Panel Finite Element Simulation

NASA Technical Reports Server (NTRS)

Fasanella, Edwin L.; Jackson, Karen E.; Lyle, Karen H.; Spellman, Regina L.

2006-01-01

A study was performed to examine the influence of varying mesh density on an LS-DYNA simulation of a rectangular-shaped foam projectile impacting the space shuttle leading edge Panel 6. The shuttle leading-edge panels are fabricated of reinforced carbon-carbon (RCC) material. During the study, nine cases were executed with all possible combinations of coarse, baseline, and fine meshes of the foam and panel. For each simulation, the same material properties and impact conditions were specified and only the mesh density was varied. In the baseline model, the shell elements representing the RCC panel are approximately 0.2-in. on edge, whereas the foam elements are about 0.5-in. on edge. The element nominal edge-length for the baseline panel was halved to create a fine panel (0.1-in. edge length) mesh and doubled to create a coarse panel (0.4-in. edge length) mesh. In addition, the element nominal edge-length of the baseline foam projectile was halved (0.25-in. edge length) to create a fine foam mesh and doubled (1.0-in. edge length) to create a coarse foam mesh. The initial impact velocity of the foam was 775 ft/s. The simulations were executed in LS-DYNA for 6 ms of simulation time. Contour plots of resultant panel displacement and effective stress in the foam were compared at four discrete time intervals. Also, time-history responses of internal and kinetic energy of the panel, kinetic and hourglass energy of the foam, and resultant contact force were plotted to determine the influence of mesh density.

Demonstration of space-resolved x-ray Thomson scattering capability for warm dense matter experiments on the Z accelerator

DOE PAGES

Ao, T.; Harding, E. C.; Bailey, J. E.; ...

2016-01-13

Experiments on the Sandia Z pulsed-power accelerator demonstrated the ability to produce warm dense matter (WDM) states with unprecedented uniformity, duration, and size, which are ideal for investigations of fundamental WDM properties. For the first time, space-resolved x-ray Thomson scattering (XRTS) spectra from shocked carbon foams were recorded on Z. The large (> 20 MA) electrical current produced by Z was used to launch Al flyer plates up to 25 km/s. The impact of the flyer plate on a CH 2 foam target produced a shocked state with an estimated pressure of 0.75 Mbar, density of 0.52 g/cm 3, andmore » temperature of 4.3 eV. Both unshocked and shocked portions of the foam target were probed with 6.2 keV x-rays produced by focusing the Z-Beamlet laser onto a nearby Mn foil. The data is composed of three spatially distinct spectra that were simultaneously captured with a single spectrometer with high spectral (4.8 eV) and spatial (190 μm) resolutions. Furthermore, these spectra provide detailed information on three target locations: the laser spot, the unshocked foam, and the shocked foam.« less

Space Shuttle Projects

NASA Image and Video Library

2004-09-13

The Space Shuttle External Tank 120 is shown here during transfer in NASA’s Michoud Assembly Facility in New Orleans. Slated for launch on the Orbiter Discovery scheduled for next Spring, the tank will be erected vertically in preparation for its new foam application process on the liquid hydrogen tank-to-inter tank flange area, a tank structural connection point. The foam will be applied with an enhanced finishing procedure that requires two technicians, one for a new mold-injection procedure to the intertank’s ribbing and one for real-time videotaped surveillance of the process. Marshall Space Flight Center played a significant role in the development of the new application process designed to replace the possible debris shedding source previously used.

Space Shuttle Projects

NASA Image and Video Library

2004-09-13

The Space Shuttle External Tank 120 is shown here in its vertical position in NASA’s Michoud Assembly Facility in New Orleans. Slated for launch on the Orbiter Discovery scheduled for next Spring, the tank is in position for its new foam application process on the liquid hydrogen tank-to-inter tank flange area, a tank structural connection point. The foam will be applied with an enhanced finishing procedure that requires two technicians, one for a new mold-injection procedure to the intertank’s ribbing and one for real-time videotaped surveillance of the process. Marshall Space Flight Center played a significant role in the development of the new application process designed to replace the possible debris shedding source previously used.

Characterization of 17-4 PH stainless steel foam for biomedical applications in simulated body fluid and artificial saliva environments.

PubMed

Mutlu, Ilven; Oktay, Enver

2013-04-01

Highly porous 17-4 PH stainless steel foam for biomedical applications was produced by space holder technique. Metal release and weight loss from 17-4 PH stainless steel foams was investigated in simulated body fluid and artificial saliva environments by static immersion tests. Inductively coupled plasma-mass spectrometer was employed to measure the concentrations of various metal ions released from the 17-4 PH stainless steel foams into simulated body fluids and artificial saliva. Effect of immersion time and pH value on metal release and weight loss in simulated body fluid and artificial saliva were determined. Pore morphology, pore size and mechanical properties of the 17-4 PH stainless steel foams were close to human cancellous bone. Copyright © 2012 Elsevier B.V. All rights reserved.

An Overview of Spray-On Foam Insulation Applications on the Space Shuttle's External Tank: Foam Applications and Foam Shedding Mechanisms

NASA Technical Reports Server (NTRS)

Sullivan, Roy M.; Lerch, Bradley A.; Rogers, Patrick R.; Sparks, Scotty S.

2006-01-01

The Columbia Accident Investigation Board (CAIB) concluded that the cause of the tragic loss of the Space Shuttle Columbia and its crew was a breach in the thermal protection system on the leading edge of the left wing. The breach was initiated by a piece of insulating foam that separated from the left bipod ramp of the External Tank and struck the wing in the vicinity of the lower half of Reinforced Carbon-Carbon panel No. 8 at 81.9 seconds after launch. The CAIB conclusion has spawned numerous studies to identify the cause of and factors influencing foam shedding and foam debris liberation from the External Tank during ascent. The symposium on the Thermo-mechanics and Fracture of Space Shuttle External Tank Spray-On Foam Insulation is a collection of presentations that discuss the physics and mechanics of the ET SOFI with the objective of improving analytical and numerical methods for predicting foam thermo-mechanical and fracture behavior. This keynote presentation sets the stage for the presentations contained in this symposium by introducing the audience to the various types of SOFI applications on the Shuttle s External Tank and by discussing the various mechanisms that are believed to be the cause of foam shedding during the Shuttle s ascent to space

Integrated Microfluidic Flow-Through Microbial Fuel Cells

PubMed Central

Jiang, Huawei; Ali, Md. Azahar; Xu, Zhen; Halverson, Larry J.; Dong, Liang

2017-01-01

This paper reports on a miniaturized microbial fuel cell with a microfluidic flow-through configuration: a porous anolyte chamber is formed by filling a microfluidic chamber with three-dimensional graphene foam as anode, allowing nutritional medium to flow through the chamber to intimately interact with the colonized microbes on the scaffolds of the anode. No nutritional media flow over the anode. This allows sustaining high levels of nutrient utilization, minimizing consumption of nutritional substrates, and reducing response time of electricity generation owing to fast mass transport through pressure-driven flow and rapid diffusion of nutrients within the anode. The device provides a volume power density of 745 μW/cm3 and a surface power density of 89.4 μW/cm2 using Shewanella oneidensis as a model biocatalyst without any optimization of bacterial culture. The medium consumption and the response time of the flow-through device are reduced by 16.4 times and 4.2 times, respectively, compared to the non-flow-through counterpart with its freeway space volume six times the volume of graphene foam anode. The graphene foam enabled microfluidic flow-through approach will allow efficient microbial conversion of carbon-containing bioconvertible substrates to electricity with smaller space, less medium consumption, and shorter start-up time. PMID:28120875

Integrated Microfluidic Flow-Through Microbial Fuel Cells

NASA Astrophysics Data System (ADS)

Jiang, Huawei; Ali, Md. Azahar; Xu, Zhen; Halverson, Larry J.; Dong, Liang

2017-01-01

This paper reports on a miniaturized microbial fuel cell with a microfluidic flow-through configuration: a porous anolyte chamber is formed by filling a microfluidic chamber with three-dimensional graphene foam as anode, allowing nutritional medium to flow through the chamber to intimately interact with the colonized microbes on the scaffolds of the anode. No nutritional media flow over the anode. This allows sustaining high levels of nutrient utilization, minimizing consumption of nutritional substrates, and reducing response time of electricity generation owing to fast mass transport through pressure-driven flow and rapid diffusion of nutrients within the anode. The device provides a volume power density of 745 μW/cm3 and a surface power density of 89.4 μW/cm2 using Shewanella oneidensis as a model biocatalyst without any optimization of bacterial culture. The medium consumption and the response time of the flow-through device are reduced by 16.4 times and 4.2 times, respectively, compared to the non-flow-through counterpart with its freeway space volume six times the volume of graphene foam anode. The graphene foam enabled microfluidic flow-through approach will allow efficient microbial conversion of carbon-containing bioconvertible substrates to electricity with smaller space, less medium consumption, and shorter start-up time.

Prototype Aerogel Insulation for Melamine-Foam Substitute: Critical Space Station Express Rack Technology

NASA Technical Reports Server (NTRS)

Noever, David A.; Sibille, Laurent; Smith, David; Cronise, Raymond

1998-01-01

There is a current lack of environmentally acceptable foams to insulate Long-Duration Human Spaceflight Missions, including the experimental Express Rack for the Space Station. A recent 60-day manned test in a sealed chamber at Johnson Space Center (JSC) was nearly aborted, because of persistently high formaldehyde concentrations in the chamber. Subsequent investigation showed that the source was melamine foam (used extensively for acoustic insulation). The thermal and acoustic potential for melamine-foam substitutes is evaluated for scale-up to a silica-based foam and aerogel, which is environmentally benign for long duration space flight. These features will be discussed in reference to an aerogel prototype to: 1) assemble material strength data for various formulated aerogels, both silica and organic carbon aerogels; 2) assemble the aerogel into panels of mylar/vacuum-encapsulated rigid boards which can be molded in various shapes and rigidities; and 3) describe a process for space applications for formaldehyde-free, long duration thermal and acoustic insulators.

The Influence of Mesh Density on the Impact Response of a Shuttle Leading-Edge Panel Finite Element Simulation

NASA Technical Reports Server (NTRS)

Jackson, Karen E.; Fasanella, Edwin L.; Lyle, Karen H.; Spellman, Regina L.

2004-01-01

A study was performed to examine the influence of varying mesh density on an LS-DYNA simulation of a rectangular-shaped foam projectile impacting the space shuttle leading edge Panel 6. The shuttle leading-edge panels are fabricated of reinforced carbon-carbon (RCC) material. During the study, nine cases were executed with all possible combinations of coarse, baseline, and fine meshes of the foam and panel. For each simulation, the same material properties and impact conditions were specified and only the mesh density was varied. In the baseline model, the shell elements representing the RCC panel are approximately 0.2-in. on edge, whereas the foam elements are about 0.5-in. on edge. The element nominal edge-length for the baseline panel was halved to create a fine panel (0.1-in. edge length) mesh and doubled to create a coarse panel (0.4-in. edge length) mesh. In addition, the element nominal edge-length of the baseline foam projectile was halved (0.25-in. edge length) to create a fine foam mesh and doubled (1.0- in. edge length) to create a coarse foam mesh. The initial impact velocity of the foam was 775 ft/s. The simulations were executed in LS-DYNA version 960 for 6 ms of simulation time. Contour plots of resultant panel displacement and effective stress in the foam were compared at five discrete time intervals. Also, time-history responses of internal and kinetic energy of the panel, kinetic and hourglass energy of the foam, and resultant contact force were plotted to determine the influence of mesh density. As a final comparison, the model with a fine panel and fine foam mesh was executed with slightly different material properties for the RCC. For this model, the average degraded properties of the RCC were replaced with the maximum degraded properties. Similar comparisons of panel and foam responses were made for the average and maximum degraded models.

Active Debris Removal System Based on Polyurethane Foam

NASA Astrophysics Data System (ADS)

Rizzitelli, Federico; Valdatta, Marcelo; Bellini, Niccolo; Candini Gian, Paolo; Rastelli, Davide; Romei, Fedrico; Locarini, Alfredo; Spadanuda, Antonio; Bagassi, Sara

2013-08-01

Space debris is an increasing problem. The exponential increase of satellite launches in the last 50 years has determined the problem of space debris especially in LEO. The remains of past missions are dangerous for both operative satellites and human activity in space. But not only: it has been shown that uncontrolled impacts between space objects can lead to a potentially dangerous situation for civil people on Earth. It is possible to reach a situation of instability where the big amount of debris could cause a cascade of collisions, the so called Kessler syndrome, resulting in the infeasibility of new space missions for many generations. Currently new technologies for the mitigation of space debris are under study: for what concerning the removal of debris the use of laser to give a little impulse to the object and push it in a graveyard orbit or to be destroyed in the atmosphere. Another solution is the use of a satellite to rendezvous with the space junk and then use a net to capture it and destroy it in the reentry phase. In a parallel way the research is addressed to the study of deorbiting solutions to prevent the formation of new space junk. The project presented in this paper faces the problem of how to deorbit an existing debris, applying the studies about the use of polyurethane foam developed by Space Robotic Group of University of Bologna. The research is started with the Redemption experiment part of last ESA Rexus program. The foam is composed by two liquid components that, once properly mixed, trig an expansive reaction leading to an increase of volume whose entity depends on the chemical composition of the two starting components. It is possible to perform two kind of mission: 1) Not controlled removal: the two components are designed to react producing a low density, high expanded, spongy foam that incorporates the debris. The A/m ratio of the debris is increased and in this way also the ballistic parameter. As a consequence, the effect of atmospheric drag increases and the orbit life time is reduced. 2) Controlled removal: the reaction of the two components leads to a high density, medium expanded, rigid foam. The idea is to create a link between the satellite and the object: in this case the deorbit is performed by the cleaner satellite propulsion, in a smaller time compared to the first configuration. Several tests and designs are in implemented to achieve the goals of the research.

"Go Be a Writer": Intra-Activity with Materials, Time and Space in Literacy Learning

ERIC Educational Resources Information Center

Kuby, Candace R.; Rucker, Tara Gutshall; Kirchhofer, Jessica M.

2015-01-01

This article is based on research in a United States second-grade classroom during a multimodal literacy workshop. Observing students working with tissue paper, foam board, string, pipe cleaners and other materials, we asked how is intra-activity with materials, time and space influencing literacy learning in Room 203? While the research…

A tetraquark or not a tetraquark? A holography inspired stringy hadron (HISH) perspective

NASA Astrophysics Data System (ADS)

Sonnenschein, Jacob; Weissman, Dorin

2017-07-01

We suggest to use the state Y (4630), which decays predominantly to ΛcΛ‾c, as a window to the landscape of tetraquarks. We propose a simple criterion to decide whether a state is a stringy exotic hadron - a tetraquark - or a ;molecule;. If it is the former it should be on a (modified) Regge trajectory. We present the predictions of the mass and width of the higher excited states on the Y (4630) trajectory. We argue that there should exist an analogous Yb state that decays to ΛbΛ‾b and describe its trajectory. We conjecture also a similar trajectory for tetraquarks containing strange quarks, and the modified Regge trajectories can in fact be predicted for any resonances found decaying to a baryon-antibaryon pair. En route to the results regarding tetraquarks, we also make some additional predictions on higher excited charmonium states. We briefly discuss the zoo of exotic stringy hadrons and in particular we sketch all the possibilities of tetraquark states.

Infiltrated carbon foam composites

NASA Technical Reports Server (NTRS)

Lucas, Rick D. (Inventor); Danford, Harry E. (Inventor); Plucinski, Janusz W. (Inventor); Merriman, Douglas J. (Inventor); Blacker, Jesse M. (Inventor)

2012-01-01

An infiltrated carbon foam composite and method for making the composite is described. The infiltrated carbon foam composite may include a carbonized carbon aerogel in cells of a carbon foam body and a resin is infiltrated into the carbon foam body filling the cells of the carbon foam body and spaces around the carbonized carbon aerogel. The infiltrated carbon foam composites may be useful for mid-density ablative thermal protection systems.

Structural Continuum Modeling of Space Shuttle External Tank Foam Insulation

NASA Technical Reports Server (NTRS)

Steeve, Brian; Ayala, Sam; Purlee, T. Eric; Shaw, Phillip

2006-01-01

The Space Shuttle External Tank is covered with rigid polymeric closed-cell foam insulation to prevent ice formation, protect the metallic tank from aerodynamic heating, and control the breakup of the tank during re-entry. The cryogenic state of the tank, as well as the ascent into a vacuum environment, places this foam under significant stress. Because the loss of the foam during ascent poses a critical risk to the shuttle orbiter, there is much interest in understanding the stress state in the foam insulation and how it may contribute to fracture and debris loss. Several foam applications on the external tank have been analyzed using finite element methods. This presentation describes the approach used to model the foam material behavior and compares analytical results to experiments.

KSC-07pd0563

NASA Image and Video Library

2007-03-04

KENNEDY SPACE CENTER, FLA. -- Space Shuttle Atlantis, atop the mobile launcher platform, rolls toward the Vehicle Assembly Building. In the VAB, the shuttle will be examined for hail damage. A severe thunderstorm with golf ball-sized hail caused divots in the giant tank's foam insulation and minor surface damage to about 26 heat shield tiles on the shuttle's left wing. Further evaluation of the tank is necessary to get an accurate accounting of foam damage and determine the type of repair required and the time needed for that work. A new target launch date has not been determined, but teams will focus on preparing Atlantis for liftoff in late April. Photo credit: NASA/Amanda Diller

Mission STS-134: Results of Shape Memory Foam Experiment

NASA Astrophysics Data System (ADS)

Santo, Loredana; Quadrini, Fabrizio; Mascetti, Gabriele; Dolce, Ferdinando; Zolesi, Valfredo

2013-10-01

Shape memory epoxy foams were used for an experiment aboard the International Space Station (ISS) to evaluate the feasibility of their use for building light actuators and expandable/deployable structures. The experiment named I-FOAM was performed by an autonomous device contained in the BIOKON container (by Kayser Italia) which was in turn composed of control and heating system, battery pack and data acquisition system. To simulate the actuation of simple devices in micro-gravity conditions, three different configurations (compression, bending and torsion) were chosen during the memory step of the foams so as to produce their recovery on ISS. Micro-gravity does not affect the ability of the foams to recover their shape but it poses limits for the heating system design because of the difference in heat transfer on Earth and in orbit. A recovery about 70% was measured at a temperature of 110 °C for the bending and torsion configuration whereas poor recovery was observed for the compression case. Thanks to these results, a new experiment has been developed for a future mission by the same device: for the first time a shape memory composite will be recovered, and the actuation load during time will be measured during the recovery of an epoxy foam sample.

Space Shuttle Atlantis' external tank repairs from Hail Damage

NASA Image and Video Library

2007-04-09

In the Vehicle Assembly Building, United Space Alliance technicians Brenda Morris and Brian Williams are applying foam and molds on Space Shuttle Atlantis' external tank to areas damaged by hail. The white hole with a red circle around it (upper right) is a hole prepared for molding and material application. The red material is sealant tape so the mold doesn't leak when the foam rises against the mold. The white/ translucent square mold is an area where the foam has been applied and the foam has risen and cured against the mold surface. In late February, Atlantis' external tank received hail damage during a severe thunderstorm that passed through the Kennedy Space Center Launch Complex 39 area. The hail caused visible divots in the giant tank's foam insulation as well as minor surface damage to about 26 heat shield tiles on the shuttle's left wing. The March launch was postponed and has not yet been rescheduled due to the repair process.

KSC-07pd0849

NASA Image and Video Library

2007-04-09

KENNEDY SPACE CENTER, FLA. -- In the Vehicle Assembly Building, United Space Alliance technicians Brenda Morris and Brian Williams are applying foam and molds on Space Shuttle Atlantis' external tank to areas damaged by hail. The white hole with a red circle around it (upper right) is a hole prepared for molding and material application. The red material is sealant tape so the mold doesn't leak when the foam rises against the mold. The white/translucent square mold is an area where the foam has been applied and the foam has risen and cured against the mold surface. In late February, Atlantis' external tank received hail damage during a severe thunderstorm that passed through the Kennedy Space Center Launch Complex 39 area. The hail caused visible divots in the giant tank's foam insulation as well as minor surface damage to about 26 heat shield tiles on the shuttle's left wing. The March launch was postponed and has not yet been rescheduled due to the repair process. Photo credit: NASA/George Shelton

Quantum no-scale regimes in string theory

NASA Astrophysics Data System (ADS)

Coudarchet, Thibaut; Fleming, Claude; Partouche, Hervé

2018-05-01

We show that in generic no-scale models in string theory, the flat, expanding cosmological evolutions found at the quantum level can be attracted to a "quantum no-scale regime", where the no-scale structure is restored asymptotically. In this regime, the quantum effective potential is dominated by the classical kinetic energies of the no-scale modulus and dilaton. We find that this natural preservation of the classical no-scale structure at the quantum level occurs when the initial conditions of the evolutions sit in a subcritical region of their space. On the contrary, supercritical initial conditions yield solutions that have no analogue at the classical level. The associated intrinsically quantum universes are sentenced to collapse and their histories last finite cosmic times. Our analysis is done at 1-loop, in perturbative heterotic string compactified on tori, with spontaneous supersymmetry breaking implemented by a stringy version of the Scherk-Schwarz mechanism.

Photogrammetric Trajectory Estimation of Foam Debris Ejected From an F-15 Aircraft

NASA Technical Reports Server (NTRS)

Smith, Mark S.

2006-01-01

Photogrammetric analysis of high-speed digital video data was performed to estimate trajectories of foam debris ejected from an F-15B aircraft. This work was part of a flight test effort to study the transport properties of insulating foam shed by the Space Shuttle external tank during ascent. The conical frustum-shaped pieces of debris, called "divots," were ejected from a flight test fixture mounted underneath the F-15B aircraft. Two onboard cameras gathered digital video data at two thousand frames per second. Time histories of divot positions were determined from the videos post flight using standard photogrammetry techniques. Divot velocities were estimated by differentiating these positions with respect to time. Time histories of divot rotations were estimated using four points on the divot face. Estimated divot position, rotation, and Mach number for selected cases are presented. Uncertainty in the results is discussed.

A Monte Carlo Approach to Modeling the Breakup of the Space Launch System EM-1 Core Stage with an Integrated Blast and Fragment Catalogue

NASA Technical Reports Server (NTRS)

Richardson, Erin; Hays, M. J.; Blackwood, J. M.; Skinner, T.

2014-01-01

The Liquid Propellant Fragment Overpressure Acceleration Model (L-FOAM) is a tool developed by Bangham Engineering Incorporated (BEi) that produces a representative debris cloud from an exploding liquid-propellant launch vehicle. Here it is applied to the Core Stage (CS) of the National Aeronautics and Space Administration (NASA) Space Launch System (SLS launch vehicle). A combination of Probability Density Functions (PDF) based on empirical data from rocket accidents and applicable tests, as well as SLS specific geometry are combined in a MATLAB script to create unique fragment catalogues each time L-FOAM is run-tailored for a Monte Carlo approach for risk analysis. By accelerating the debris catalogue with the BEi blast model for liquid hydrogen / liquid oxygen explosions, the result is a fully integrated code that models the destruction of the CS at a given point in its trajectory and generates hundreds of individual fragment catalogues with initial imparted velocities. The BEi blast model provides the blast size (radius) and strength (overpressure) as probabilities based on empirical data and anchored with analytical work. The coupling of the L-FOAM catalogue with the BEi blast model is validated with a simulation of the Project PYRO S-IV destruct test. When running a Monte Carlo simulation, L-FOAM can accelerate all catalogues with the same blast (mean blast, 2 s blast, etc.), or vary the blast size and strength based on their respective probabilities. L-FOAM then propagates these fragments until impact with the earth. Results from L-FOAM include a description of each fragment (dimensions, weight, ballistic coefficient, type and initial location on the rocket), imparted velocity from the blast, and impact data depending on user desired application. LFOAM application is for both near-field (fragment impact to escaping crew capsule) and far-field (fragment ground impact footprint) safety considerations. The user is thus able to use statistics from a Monte Carlo set of L-FOAM catalogues to quantify risk for a multitude of potential CS destruct scenarios. Examples include the effect of warning time on the survivability of an escaping crew capsule or the maximum fragment velocities generated by the ignition of leaking propellants in internal cavities.

46 CFR 95.17-5 - Quantity of foam required.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Quantity of foam required. 95.17-5 Section 95.17-5... PROTECTION EQUIPMENT Foam Extinguishing Systems, Details § 95.17-5 Quantity of foam required. (a) Area... blanket of foam over the entire tank top or bilge of the space protected. The arrangement of piping shall...

46 CFR 76.17-5 - Quantity of foam required.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 3 2013-10-01 2013-10-01 false Quantity of foam required. 76.17-5 Section 76.17-5... EQUIPMENT Foam Extinguishing Systems, Details § 76.17-5 Quantity of foam required. (a) Area protected. (1... of foam over the entire tank top or bilge of the space protected. The arrangement of piping shall be...

46 CFR 76.17-5 - Quantity of foam required.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 3 2012-10-01 2012-10-01 false Quantity of foam required. 76.17-5 Section 76.17-5... EQUIPMENT Foam Extinguishing Systems, Details § 76.17-5 Quantity of foam required. (a) Area protected. (1... of foam over the entire tank top or bilge of the space protected. The arrangement of piping shall be...

46 CFR 76.17-5 - Quantity of foam required.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 3 2014-10-01 2014-10-01 false Quantity of foam required. 76.17-5 Section 76.17-5... EQUIPMENT Foam Extinguishing Systems, Details § 76.17-5 Quantity of foam required. (a) Area protected. (1... of foam over the entire tank top or bilge of the space protected. The arrangement of piping shall be...

46 CFR 76.17-5 - Quantity of foam required.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 3 2010-10-01 2010-10-01 false Quantity of foam required. 76.17-5 Section 76.17-5... EQUIPMENT Foam Extinguishing Systems, Details § 76.17-5 Quantity of foam required. (a) Area protected. (1... of foam over the entire tank top or bilge of the space protected. The arrangement of piping shall be...

46 CFR 76.17-5 - Quantity of foam required.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 3 2011-10-01 2011-10-01 false Quantity of foam required. 76.17-5 Section 76.17-5... EQUIPMENT Foam Extinguishing Systems, Details § 76.17-5 Quantity of foam required. (a) Area protected. (1... of foam over the entire tank top or bilge of the space protected. The arrangement of piping shall be...

46 CFR 95.17-5 - Quantity of foam required.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Quantity of foam required. 95.17-5 Section 95.17-5... PROTECTION EQUIPMENT Foam Extinguishing Systems, Details § 95.17-5 Quantity of foam required. (a) Area... blanket of foam over the entire tank top or bilge of the space protected. The arrangement of piping shall...

46 CFR 95.17-5 - Quantity of foam required.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Quantity of foam required. 95.17-5 Section 95.17-5... PROTECTION EQUIPMENT Foam Extinguishing Systems, Details § 95.17-5 Quantity of foam required. (a) Area... blanket of foam over the entire tank top or bilge of the space protected. The arrangement of piping shall...

46 CFR 95.17-5 - Quantity of foam required.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Quantity of foam required. 95.17-5 Section 95.17-5... PROTECTION EQUIPMENT Foam Extinguishing Systems, Details § 95.17-5 Quantity of foam required. (a) Area... blanket of foam over the entire tank top or bilge of the space protected. The arrangement of piping shall...

46 CFR 95.17-5 - Quantity of foam required.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Quantity of foam required. 95.17-5 Section 95.17-5... PROTECTION EQUIPMENT Foam Extinguishing Systems, Details § 95.17-5 Quantity of foam required. (a) Area... blanket of foam over the entire tank top or bilge of the space protected. The arrangement of piping shall...

KSC-07pd0886

NASA Image and Video Library

2007-04-13

KENNEDY SPACE CENTER, FLA. -- In the Vehicle Assembly Building, Mike Ravenscroft, with United Space Alliance, points to some of the foam repair done on the external tank of Space Shuttle Atlantis. Holes filled with foam are sanded flush with the adjacent area. In late February, Atlantis' external tank received hail damage during a severe thunderstorm that passed through the Kennedy Space Center Launch Complex 39 area. The hail caused visible divots in the giant tank's foam insulation as well as minor surface damage to about 26 heat shield tiles on the shuttle's left wing. The launch now is targeted for June 8. Photo credit: NASA/George Shelton

Fracture Toughness Evaluation of Space Shuttle External Tank Thermal Protection System Polyurethane Foam Insulation Materials

NASA Technical Reports Server (NTRS)

McGill, Preston; Wells, Doug; Morgan, Kristin

2006-01-01

Experimental evaluation of the basic fracture properties of Thermal Protection System (TPS) polyurethane foam insulation materials was conducted to validate the methodology used in estimating critical defect sizes in TPS applications on the Space Shuttle External Fuel Tank. The polyurethane foam found on the External Tank (ET) is manufactured by mixing liquid constituents and allowing them to react and expand upwards - a process which creates component cells that are generally elongated in the foam rise direction and gives rise to mechanical anisotropy. Similarly, the application of successive foam layers to the ET produces cohesive foam interfaces (knitlines) which may lead to local variations in mechanical properties. This study reports the fracture toughness of BX-265, NCFI 24-124, and PDL-1034 closed-cell polyurethane foam as a function of ambient and cryogenic temperatures and knitline/cellular orientation at ambient pressure.

The Influence of Clocking Angle of the Projectile on the Simulated Impact Response of a Shuttle Leading Edge Wing Panel

NASA Technical Reports Server (NTRS)

Jackson, Karen E.; Fasanella, Edwin L.; Lyle, Karen H.; Spellman, Regina L.

2005-01-01

An analytical study was conducted to determine the influence of clocking angle of a foam projectile impacting a space shuttle leading edge wing panel. Four simulations were performed using LS-DYNA. The leading edge panels are fabricated of multiple layers of reinforced carbon-carbon (RCC) material. The RCC material was represented using Mat 58, which is a material property that can be used for laminated composite fabrics. Simulations were performed of a rectangular-shaped foam block, weighing 0.23-lb., impacting RCC Panel 9 on the top surface. The material properties of the foam were input using Mat 83. The impact velocity was 1,000 ft/s along the Orbiter X-axis. In two models, the foam impacted on a corner, in one model the foam impacted the panel initially on the 2-in.-long edge, and in the last model the foam impacted the panel on the 7-in.- long edge. The simulation results are presented as contour plots of first principal infinitesimal strain and time history plots of contact force and internal and kinetic energy of the foam and RCC panel.

Foam-on-Tile Damage Model

NASA Technical Reports Server (NTRS)

Koharchik, Michael; Murphy, Lindsay; Parker, Paul

2012-01-01

An impact model was developed to predict how three specific foam types would damage the Space Shuttle Orbiter insulating tiles. The inputs needed for the model are the foam type, the foam mass, the foam impact velocity, the foam impact incident angle, the type being impacted, and whether the tile is new or aged (has flown at least one mission). The model will determine if the foam impact will cause damage to the tile. If it can cause damage, the model will output the damage cavity dimensions (length, depth, entry angle, exit angle, and sidewall angles). It makes the calculations as soon as the inputs are entered (less than 1 second). The model allows for the rapid calculation of numerous scenarios in a short time. The model was developed from engineering principles coupled with significant impact testing (over 800 foam impact tests). This model is applicable to masses ranging from 0.0002 up to 0.4 pound (0.09 up to 181 g). A prior tool performed a similar function, but was limited to the assessment of a small range of masses and did not have the large test database for verification. In addition, the prior model did not provide outputs of the cavity damage length, entry angle, exit angle, or sidewall angles.

Atomic Oxygen Exposure of Polyimide Foam for International Space Station Solar Array Wing Blanket Box

NASA Technical Reports Server (NTRS)

Finckenor, M. M.; Albyn, K. C.; Watts, E. W.

2006-01-01

Onorbit photos of the International Space Station (ISS) solar array blanket box foam pad assembly indicate degradation of the Kapton film covering the foam, leading to atomic oxygen (AO) exposure of the foam. The purpose of this test was to determine the magnitude of particulate generation caused by low-Earth orbital environment exposure of the foam and also by compression of the foam during solar array wing retraction. The polyimide foam used in the ISS solar array wing blanket box assembly is susceptible to significant AO erosion. The foam sample in this test lost one-third of its mass after exposure to the equivalent of 22 mo onorbit. Some particulate was generated by exposure to simulated orbital conditions and the simulated solar array retraction (compression test). However, onorbit, these particles would also be eroded by AO. The captured particles were generally <1 mm, and the particles shaken free of the sample had a maximum size of 4 mm. The foam sample maintained integrity after a compression load of 2.5 psi.

Holding Cargo in Place With Foam

NASA Technical Reports Server (NTRS)

Fisher, T. T.

1985-01-01

Foam fills entire container to protect cargo from shock and vibration. Originally developed for stowing space debris and spent satellites in Space Shuttle for return to Earth, encapsulation concept suitable for preparing shipments carried by truck, boat, or airplane. Equipment automatically injects polyurethane foam into its interior to hold cargo securely in place. Container of rectangular or other cross section built to match shape of vehicle used.

Cryoinsulation Material Development to Mitigate Obsolescence Risk for Global Warming Potential Foams

NASA Technical Reports Server (NTRS)

Protz, Alison; Bruyns, Roland; Nettles, Mindy

2015-01-01

Cryoinsulation foams currently being qualified for the Space Launch System (SLS) core stage are nonozone- depleting substances (ODP) and are compliant with current environmental regulations. However, these materials contain the blowing agent HFC-245fa, a hydrofluorocarbon (HFC), which is a Global Warming Potential (GWP) substance. In August 2014, the Environmental Protection Agency (EPA) proposed a policy change to reduce or eliminate certain HFCs, including HFC-245fa, in end-use categories including foam blowing agents beginning in 2017. The policy proposes a limited exception to allow continued use of HFC and HFC-blend foam blowing agents for military or space- and aeronautics-related applications, including rigid polyurethane spray foams, but only until 2022.

High Expansion Foam for Protecting Large Volume Mission Critical Shipboard Spaces

DTIC Science & Technology

2009-01-01

aqueous film - forming foam ( AFFF ) sprinklers designed only to combat Class B two-dimensional pool fires.1 The...Validation Tests, Series 1 – An Evaluation of Aqueous Film Foaming Foam ( AFFF ) Suppression Systems for Protection of LHA(R) Well Deck and Vehicle... firefighting system design. NRL further recognized that employing a traditional high expansion foam generator would impact shipboard

KSC-07pd0565

NASA Image and Video Library

2007-03-04

KENNEDY SPACE CENTER, FLA. -- Space Shuttle Atlantis, atop the mobile launcher platform, rolls into the Vehicle Assembly Building after leaving Launch Pad 39A. In the VAB, the shuttle will be examined for hail damage. A severe thunderstorm with golf ball-sized hail caused divots in the giant tank's foam insulation and minor surface damage to about 26 heat shield tiles on the shuttle's left wing. Further evaluation of the tank is necessary to get an accurate accounting of foam damage and determine the type of repair required and the time needed for that work. A new target launch date has not been determined, but teams will focus on preparing Atlantis for liftoff in late April. Photo credit: NASA/Amanda Diller

KSC-07pd0569

NASA Image and Video Library

2007-03-04

KENNEDY SPACE CENTER, FLA. -- After leaving Launch Pad 39A, Space Shuttle Atlantis, atop the mobile launcher platform, comes to rest in high bay 1 of the Vehicle Assembly Building. A severe thunderstorm with golf ball-sized hail caused divots in the giant tank's foam insulation and minor surface damage to about 26 heat shield tiles on the shuttle's left wing. Further evaluation of the tank is necessary to get an accurate accounting of foam damage and determine the type of repair required and the time needed for that work. A new target launch date has not been determined, but teams will focus on preparing Atlantis for liftoff in late April. Photo credit: NASA/Amanda Diller

Microwave and Millimeter Wave Nondestructive Evaluation of the Space Shuttle External Tank Insulating Foam

NASA Technical Reports Server (NTRS)

Shrestha, S.; Kharkovsky, S.; Zoughi, R.; Hepburn, F

2005-01-01

The Space Shuttle Columbia s catastrophic failure has been attributed to a piece of external fuel tank insulating SOFI (Spray On Foam Insulation) foam striking the leading edge of the left wing of the orbiter causing significant damage to some of the protecting heat tiles. The accident emphasizes the growing need to develop effective, robust and life-cycle oriented methods of nondestructive testing and evaluation (NDT&E) of complex conductor-backed insulating foam and protective acreage heat tiles used in the space shuttle fleet and in future multi-launch space vehicles. The insulating SOFI foam is constructed from closed-cell foam. In the microwave regime this foam is in the family of low permittivity and low loss dielectric materials. Near-field microwave and millimeter wave NDT methods were one of the techniques chosen for this purpose. To this end several flat and thick SOFI foam panels, two structurally complex panels similar to the external fuel tank and a "blind" panel were used in this investigation. Several anomalies such as voids and disbonds were embedded in these panels at various locations. The location and properties of the embedded anomalies in the "blind" panel were not disclosed to the investigating team prior to the investigation. Three frequency bands were used in this investigation covering a frequency range of 8-75 GHz. Moreover, the influence of signal polarization was also investigated. Overall the results of this investigation were very promising for detecting the presence of anomalies in different panels covered with relatively thick insulating SOFI foam. Different types of anomalies were detected in foam up to 9 in thick. Many of the anomalies in the more complex panels were also detected. When investigating the blind panel no false positives were detected. Anomalies in between and underneath bolt heads were not easily detected. This paper presents the results of this investigation along with a discussion of the capabilities of the method used.

46 CFR 108.461 - Coamings.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Extinguishing Systems Foam Extinguishing Systems § 108.461 Coamings. Each machinery flat in a space that has a foam extinguishing system must have coamings that are high enough to retain spilled oil and foam on the...

46 CFR 108.461 - Coamings.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Extinguishing Systems Foam Extinguishing Systems § 108.461 Coamings. Each machinery flat in a space that has a foam extinguishing system must have coamings that are high enough to retain spilled oil and foam on the...

Technology for Transportation Safety

NASA Technical Reports Server (NTRS)

1981-01-01

Boston Insulated Wire & Cable developed a new polyimide foam material, commercially known as Solimide, which resists ignition. It chars and decomposes when exposed to open flames. Used in the space shuttle, the material does not "outgas" until it begins to char making it safer than current materials with respect to toxic fumes. The polyimide can be made in two forms: a resilient foam and a rigid foam. Used in commercial transport interiors for such soft components as seat cushions to door, wall, floor, and ceiling panels. Material's flame resistance could lengthen from two minutes to five minutes, the time needed for passenger evacuation in a ground emergency. Could help reduce airline fuel consumption, since the foam is 50% lighter than current materials. Low-smoke cable assemblies used in rapid transit systems consists of an advanced wire and cable jacketing material with superior flame resistance and smoke retardation characteristics. Being supplied to mass transit systems in the U.S. and abroad.

Analytical approach for the fractional differential equations by using the extended tanh method

NASA Astrophysics Data System (ADS)

Pandir, Yusuf; Yildirim, Ayse

2018-07-01

In this study, we consider analytical solutions of space-time fractional derivative foam drainage equation, the nonlinear Korteweg-de Vries equation with time and space-fractional derivatives and time-fractional reaction-diffusion equation by using the extended tanh method. The fractional derivatives are defined in the modified Riemann-Liouville context. As a result, various exact analytical solutions consisting of trigonometric function solutions, kink-shaped soliton solutions and new exact solitary wave solutions are obtained.

46 CFR 179.240 - Foam flotation material.

Code of Federal Regulations, 2012 CFR

2012-10-01

... accommodate the buoyancy of the foam; (5) Piping and cables must not pass through foamed spaces unless they... submerged to its bulkhead deck; (8) The effective buoyancy of the foam must be determined at the end of the submergence test required by paragraph (b)(7) of this section. The effective buoyancy or 881 kilograms per...

46 CFR 179.240 - Foam flotation material.

Code of Federal Regulations, 2013 CFR

2013-10-01

... accommodate the buoyancy of the foam; (5) Piping and cables must not pass through foamed spaces unless they... submerged to its bulkhead deck; (8) The effective buoyancy of the foam must be determined at the end of the submergence test required by paragraph (b)(7) of this section. The effective buoyancy or 881 kilograms per...

46 CFR 179.240 - Foam flotation material.

Code of Federal Regulations, 2014 CFR

2014-10-01

... accommodate the buoyancy of the foam; (5) Piping and cables must not pass through foamed spaces unless they... submerged to its bulkhead deck; (8) The effective buoyancy of the foam must be determined at the end of the submergence test required by paragraph (b)(7) of this section. The effective buoyancy or 881 kilograms per...

Deployment, Foam Rigidization, and Structural Characterization of Inflatable Thin-Film Booms

NASA Technical Reports Server (NTRS)

Schnell, Andrew R.; Leigh, Larry M., Jr.; Tinker, Michael L.; McConnaughey, Paul R. (Technical Monitor)

2002-01-01

Detailed investigation of the construction, packaging/deployment, foam rigidization, and structural characterization of polyimide film inflatable booms is described. These structures have considerable potential for use in space with solar concentrators, solar sails, space power systems including solar arrays, and other future missions. Numerous thin-film booms or struts were successfully constructed, inflated, injected with foam, and rigidized. Both solid-section and annular test articles were fabricated, using Kapton polyimide film, various adhesives, Styrofoam end plugs, and polyurethane pressurized foam. Numerous inflation/deployment experiments were conducted and compared to computer simulations using the MSC/DYTRAN code. Finite element models were developed for several foam-rigidized struts and compared to model test results. Several problems encountered in the construction, deployment, and foam injection/rigidization process are described. Areas of difficulty included inadequate adhesive strength, cracking of the film arid leakage, excessive bending of the structure during deployment, problems with foam distribution and curing properties, and control of foam leakage following injection into the structure. Many of these problems were overcome in the course of the research.

Thermal conductivity of spray-on foam insulations for aerospace applications

NASA Astrophysics Data System (ADS)

Barrios, Matt; Vanderlaan, Mark; Van Sciver, Steven

2012-06-01

A guarded-hot-plate apparatus [1] has been developed to measure the thermal conductivity of spray-on foam insulations (SOFI) at temperatures ranging from 30 K to 300 K. The foam tested in the present study is NCFI 24-124, a polyisocyanurate foam used on the External Tanks of the Space Shuttle. The foam was tested first in ambient pressure air, then evacuated and tested once more. These thermal conductivities were compared to the thermal conductivity taken from a sample immediately after being subjected to conditions similar to those experienced by the foam while on the launch pad at Kennedy Space Center. To mimic the conditions experienced on the launch pad, an apparatus was built to enclose one side of the foam sample in a warm, humid environment while the other side of the sample contacts a stainless steel surface held at 77 K. The thermal conductivity data obtained is also compared to data found in the literature.

Hail damage on Atlantis' external tank is inspected

NASA Image and Video Library

2007-04-13

In the Vehicle Assembly Building, Mike Ravenscroft, with United Space Alliance, points to some of the foam repair done on the external tank of Space Shuttle Atlantis. Holes filled with foam are sanded flush with the adjacent area. In late February, Atlantis' external tank received hail damage during a severe thunderstorm that passed through the Kennedy Space Center Launch Complex 39 area. The hail caused visible divots in the giant tank's foam insulation as well as minor surface damage to about 26 heat shield tiles on the shuttle's left wing. The launch now is targeted for June 8.

KSC-07pd0561

NASA Image and Video Library

2007-03-04

KENNEDY SPACE CENTER, FLA. -- A worker walks alongside the massive treads of the crawler-transporter that is moving Space Shuttle Atlantis back to the Vehicle Assembly Building, at right. In the VAB, the shuttle will be examined for hail damage. A severe thunderstorm with golf ball-sized hail caused divots in the giant tank's foam insulation and minor surface damage to about 26 heat shield tiles on the shuttle's left wing. Further evaluation of the tank is necessary to get an accurate accounting of foam damage and determine the type of repair required and the time needed for that work. A new target launch date has not been determined, but teams will focus on preparing Atlantis for liftoff in late April. Photo credit: NASA/Amanda Diller

KSC-07pd0562

NASA Image and Video Library

2007-03-04

KENNEDY SPACE CENTER, FLA. -- As it rolls back to the Vehicle Assembly Building, Space Shuttle Atlantis, atop the mobile launcher platform, is framed in the photo by winter-stripped branches topped by spring blossoms. In the VAB, the shuttle will be examined for hail damage. A severe thunderstorm with golf ball-sized hail caused divots in the giant tank's foam insulation and minor surface damage to about 26 heat shield tiles on the shuttle's left wing. Further evaluation of the tank is necessary to get an accurate accounting of foam damage and determine the type of repair required and the time needed for that work. A new target launch date has not been determined, but teams will focus on preparing Atlantis for liftoff in late April. Photo credit: NASA/Amanda Diller

Material characterization of rigid foam insulation at low temperature

NASA Astrophysics Data System (ADS)

Barrios, Matthew

There is a continuing need for improved rigid foam insulation, particularly for cryogenic storage aboard aerospace vehicles. The present work is a material characterization of spray-on foam insulation used on the Space Shuttle External Tank. The characterization includes imaging and measurements of thermal conductivity, ultimate tensile strength, and moisture absorption. Thermal conductivity measurements are the main focus of the present work, as it is the most relevant property to insulation performance. A novel apparatus was developed to measure the thermal conductivity of rigid foam at temperatures ranging from 20 K to 300 K with a DeltaT of 10 K between the sides of the foam sample. The effective thermal conductivity of three samples of NCFI 24-124 foam insulation was measured over the full temperature range. Additionally, the effects of different residual gases and moisture absorption on the thermal conductivity of the foam were studied. The data were compared to data from the literature and to mathematical models developed to predict the thermal conductivity. The data show that gas condensation can play a significant role in the thermal conductivity of the foam at low temperature. Moisture absorption can occur in the foam in application when cryogenic fuel is filled into a tank which sits in a warm, humid environment. An apparatus was developed to subject foam samples to these conditions. The moisture content in the samples was then measured. The samples were then imaged using the 900 MHz NMR magnet at the National High Magnetic Field Laboratory to determine the location of the water within the foam. Samples conditioned for 9 hours exhibited a 50% weight increase, and samples conditioned for 69 hours exhibited a 284% weight increase. The NMR images showed that the moisture collects first near the warm side of the foam, and permeates through the foam over time. However, the moisture appears to not collect near the knit lines (areas between sprayed layers of foam, containing cells about 10 times smaller than those that make up the bulk of the foam). The 100 kN mechanical testing system at the NHMFL was used to measure the ultimate tensile strength of the foam. The number of samples available limited the amount of measurements, but the data show that the orientation of the foam (parallel or perpendicular to the knit lines) has a greater effect on the tensile strength than does the moisture absorption or exposure to cryogenic temperature.

46 CFR 169.567 - Portable extinguishers.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Minimum size Coast Guard classification Living space and open boats 1 per 1000 cu. ft. of space Halon 1211 of 1301 21/2 pounds Foam 11/4 gallons Carbon dioxide 4 pounds B-I. Dry chemical 2 pounds Propulsion machinery space with fixed CO2 or halon system 1 Foam 11/4 gallons Carbon dioxide 4 pounds B-I. Dry chemical...

46 CFR 169.567 - Portable extinguishers.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Minimum size Coast Guard classification Living space and open boats 1 per 1000 cu. ft. of space Halon 1211 of 1301 21/2 pounds Foam 11/4 gallons Carbon dioxide 4 pounds B-I. Dry chemical 2 pounds Propulsion machinery space with fixed CO2 or halon system 1 Foam 11/4 gallons Carbon dioxide 4 pounds B-I. Dry chemical...

46 CFR 169.567 - Portable extinguishers.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Minimum size Coast Guard classification Living space and open boats 1 per 1000 cu. ft. of space Halon 1211 of 1301 21/2 pounds Foam 11/4 gallons Carbon dioxide 4 pounds B-I. Dry chemical 2 pounds Propulsion machinery space with fixed CO2 or halon system 1 Foam 11/4 gallons Carbon dioxide 4 pounds B-I. Dry chemical...

46 CFR 169.567 - Portable extinguishers.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Minimum size Coast Guard classification Living space and open boats 1 per 1000 cu. ft. of space Halon 1211 of 1301 21/2 pounds Foam 11/4 gallons Carbon dioxide 4 pounds B-I. Dry chemical 2 pounds Propulsion machinery space with fixed CO2 or halon system 1 Foam 11/4 gallons Carbon dioxide 4 pounds B-I. Dry chemical...

Foamed Bulk Metallic Glass (Foam) Investigation

NASA Technical Reports Server (NTRS)

2004-01-01

This soldering iron has an evacuated copper capsule at the tip that contains a pellet of Bulk Metallic Glass (BMG) aboard the International Space Station (ISS). Prior to flight, researchers sealed a pellet of bulk metallic glass mixed with microscopic gas-generating particles into the copper ampoule under vacuum. Once heated in space, such as in this photograph, the particles generated gas and the BMG becomes a viscous liquid. The released gas made the sample foam within the capsule where each microscopic particle formed a gas-filled pore within the foam. The inset image shows the oxidation of the sample after several minutes of applying heat. Although hidden within the brass sleeve, the sample retained the foam shape when cooled, because the viscosity increased during cooling until it was solid.

Functional integral for non-Lagrangian systems

NASA Astrophysics Data System (ADS)

Kochan, Denis

2010-02-01

A functional integral formulation of quantum mechanics for non-Lagrangian systems is presented. The approach, which we call “stringy quantization,” is based solely on classical equations of motion and is free of any ambiguity arising from Lagrangian and/or Hamiltonian formulation of the theory. The functionality of the proposed method is demonstrated on several examples. Special attention is paid to the stringy quantization of systems with a general A-power friction force -κq˙A. Results for A=1 are compared with those obtained in the approaches by Caldirola-Kanai, Bateman, and Kostin. Relations to the Caldeira-Leggett model and to the Feynman-Vernon approach are discussed as well.

Crack Initiation and Growth in Rigid Polymeric Closed-Cell Foam Cryogenic Applications

NASA Technical Reports Server (NTRS)

Sayyah, Tarek; Steeve, Brian; Wells, Doug

2006-01-01

Cryogenic vessels, such as the Space Shuttle External Tank, are often insulated with closed-cell foam because of its low thermal conductivity. The coefficient of thermal expansion mismatch between the foam and metallic substrate places the foam under a biaxial tension gradient through the foam thickness. The total foam thickness affects the slope of the stress gradient and is considered a significant contributor to the initiation of subsurface cracks. Rigid polymeric foams are brittle in nature and any subsurface cracks tend to propagate a finite distance toward the surface. This presentation investigates the relationship between foam thickness and crack initiation and subsequent crack growth, using linear elastic fracture mechanics, in a rigid polymeric closed-cell foam through analysis and comparison with experimental results.

Application of Video Image Correlation Techniques to the Space Shuttle External Tank Foam Materials

NASA Technical Reports Server (NTRS)

Hilburger, Mark W.; Nemeth, Michael P.

2005-01-01

Results that illustrate the use of a video-image-correlation-based displacement and strain measurement system to assess the effects of material nonuniformities on the behavior of the sprayed-on foam insulation (SOFI) used for the thermal protection system on the Space Shuttle External Tank are presented. Standard structural verification specimens for the SOFI material with and without cracks and subjected to mechanical or thermal loading conditions were tested. Measured full-field displacements and strains are presented for selected loading conditions to illustrate the behavior of the foam and the viability of the measurement technology. The results indicate that significant strain localization can occur in the foam because of material nonuniformities. In particular, elongated cells in the foam can interact with other geometric or material discontinuities in the foam and develop large-magnitude localized strain concentrations that likely initiate failures. Furthermore, some of the results suggest that continuum mechanics and linear elastic fracture mechanics might not adequately represent the physical behavior of the foam, and failure predictions based on homogeneous linear material models are likely to be inadequate.

Application of Video Image Correlation Techniques to the Space Shuttle External Tank Foam Materials

NASA Technical Reports Server (NTRS)

Hilburger, Mark W.; Nemeth, Michael P.

2006-01-01

Results that illustrate the use of a video-image-correlation-based displacement and strain measurement system to assess the effects of material nonuniformities on the behavior of the sprayed-on foam insulation (SOFI) used for the thermal protection system on the Space Shuttle External Tank are presented. Standard structural verification specimens for the SOFI material with and without cracks and subjected to mechanical or thermal loading conditions were tested. Measured full-field displacements and strains are presented for selected loading conditions to illustrate the behavior of the foam and the viability of the measurement technology. The results indicate that significant strain localization can occur in the foam because of material nonuniformities. In particular, elongated cells in the foam can interact with other geometric or material discontinuities in the foam and develop large-magnitude localized strain concentrations that likely initiate failures. Furthermore, some of the results suggest that continuum mechanics and linear elastic fracture mechanics might not adequately represent the physical behavior of the foam, and failure predictions based on homogeneous linear material models are likely to be inadequate.

Cryogenic Moisture Uptake in Foam Insulation for Space Launch Vehicles

NASA Technical Reports Server (NTRS)

Fesmire, James E.; ScholtensCoffman, Brekke E.; Sass, Jared P.; Williams, Martha K.; Smith, Trent M.; Meneghelli, Barrry J.

2008-01-01

Rigid polyurethane foams and rigid polyisocyanurate foams (spray-on foam insulation), like those flown on Shuttle, Delta IV, and will be flown on Ares-I and Ares-V, can gain an extraordinary amount of water when under cryogenic conditions for several hours. These foams, when exposed for eight hours to launch pad environments on one side and cryogenic temperature on the other, increase their weight from 35 to 80 percent depending on the duration of weathering or aging. This effect translates into several thousand pounds of additional weight for space vehicles at lift-off. A new cryogenic moisture uptake apparatus was designed to determine the amount of water/ice taken into the specimen under actual-use propellant loading conditions. This experimental study included the measurement of the amount of moisture uptake within different foam materials. Results of testing using both aged specimens and weathered specimens are presented. To better understand cryogenic foam insulation performance, cryogenic moisture testing is shown to be essential. The implications for future launch vehicle thermal protection system design and flight performance are discussed.

Monopropellant engine investigation for space shuttle reaction control. Volume 2: Design, fabrication, and demonstration test of a catalytic gas generator for the space shuttle APU

NASA Technical Reports Server (NTRS)

1975-01-01

The capability of a catalytic gas generator to meet the requirement specified for the space shuttle APU is established. A full-scale gas generator, designed to operate at a chamber pressure of 750 psia and a flow rate of 0.36 lbm/sec, was fabricated and subjected to three separate life test series. The nickel foam metal used for catalyst retention was investigated. Inspection of the foam metal following the first life test revealed significant degradation. Consequently an investigation was conducted to determine the mechanism of degradation and to provide an improved foam metal.

Spin-foam models and the physical scalar product

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alesci, Emanuele; Centre de Physique Theorique de Luminy, Universite de la Mediterranee, F-13288 Marseille; Noui, Karim

2008-11-15

This paper aims at clarifying the link between loop quantum gravity and spin-foam models in four dimensions. Starting from the canonical framework, we construct an operator P acting on the space of cylindrical functions Cyl({gamma}), where {gamma} is the four-simplex graph, such that its matrix elements are, up to some normalization factors, the vertex amplitude of spin-foam models. The spin-foam models we are considering are the topological model, the Barrett-Crane model, and the Engle-Pereira-Rovelli model. If one of these spin-foam models provides a covariant quantization of gravity, then the associated operator P should be the so-called ''projector'' into physical statesmore » and its matrix elements should give the physical scalar product. We discuss the possibility to extend the action of P to any cylindrical functions on the space manifold.« less

Transition probability spaces in loop quantum gravity

NASA Astrophysics Data System (ADS)

Guo, Xiao-Kan

2018-03-01

We study the (generalized) transition probability spaces, in the sense of Mielnik and Cantoni, for spacetime quantum states in loop quantum gravity. First, we show that loop quantum gravity admits the structures of transition probability spaces. This is exemplified by first checking such structures in covariant quantum mechanics and then identifying the transition probability spaces in spin foam models via a simplified version of general boundary formulation. The transition probability space thus defined gives a simple way to reconstruct the discrete analog of the Hilbert space of the canonical theory and the relevant quantum logical structures. Second, we show that the transition probability space and in particular the spin foam model are 2-categories. Then we discuss how to realize in spin foam models two proposals by Crane about the mathematical structures of quantum gravity, namely, the quantum topos and causal sites. We conclude that transition probability spaces provide us with an alternative framework to understand various foundational questions of loop quantum gravity.

Influence of foam structure on the release kinetics of volatiles from espresso coffee prior to consumption.

PubMed

Dold, Susanne; Lindinger, Christian; Kolodziejczyk, Eric; Pollien, Philippe; Ali, Santo; Germain, Juan Carlos; Perin, Sonia Garcia; Pineau, Nicolas; Folmer, Britta; Engel, Karl-Heinz; Barron, Denis; Hartmann, Christoph

2011-10-26

The relationship between the physical structure of espresso coffee foam, called crema, and the above-the-cup aroma release was studied. Espresso coffee samples were produced using the Nespresso extraction system. The samples were extracted with water with different levels of mineral content, which resulted in liquid phases with similar volatile profiles but foams with different structure properties. The structure parameters foam volume, foam drainage, and lamella film thickness at the foam surface were quantified using computer-assisted microscopic image analysis and a digital caliper. The above-the-cup volatile concentration was measured online by using PTR-MS and headspace sampling. A correlation study was done between crema structure parameters and above-the-cup volatile concentration. In the first 2.5 min after the start of the coffee extraction, the presence of foam induced an increase of concentration of selected volatile markers, independently if the crema was of high or low stability. At times longer than 2.5 min, the aroma marker concentration depends on both the stability of the crema and the volatility of the specific aroma compounds. Mechanisms of above-the-cup volatile release involved gas bubble stability, evaporation, and diffusion. It was concluded that after the initial aroma burst (during the first 2-3 min after the beginning of extraction), for the present sample space a crema of high stability provides a stronger aroma barrier over several minutes.

Glass composition and process for sealing void spaces in electrochemical devices

DOEpatents

Meinhardt, Kerry D [Richland, WA; Kirby, Brent W [Kennewick, WA

2012-05-01

A glass foaming material and method are disclosed for filling void spaces in electrochemical devices. The glass material includes a reagent that foams at a temperature above the softening point of the glass. Expansion of the glass fills void spaces including by-pass and tolerance channels of electrochemical devices. In addition, cassette to cassette seals can also be formed while channels and other void spaces are filled, reducing the number of processing steps needed.

Higher dimensional Taub-NUT spaces and applications

NASA Astrophysics Data System (ADS)

Stelea, Cristian Ionut

In the first part of this thesis we discuss classes of new exact NUT-charged solutions in four dimensions and higher, while in the remainder of the thesis we make a study of their properties and their possible applications. Specifically, in four dimensions we construct new families of axisymmetric vacuum solutions using a solution-generating technique based on the hidden SL(2,R) symmetry of the effective action. In particular, using the Schwarzschild solution as a seed we obtain the Zipoy-Voorhees generalisation of the Taub-NUT solution and of the Eguchi-Hanson soliton. Using the C-metric as a seed, we obtain and study the accelerating versions of all the above solutions. In higher dimensions we present new classes of NUT-charged spaces, generalising the previously known even-dimensional solutions to odd and even dimensions, as well as to spaces with multiple NUT-parameters. We also find the most general form of the odd-dimensional Eguchi-Hanson solitons. We use such solutions to investigate the thermodynamic properties of NUT-charged spaces in (A)dS backgrounds. These have been shown to yield counter-examples to some of the conjectures advanced in the still elusive dS/CFT paradigm (such as the maximal mass conjecture and Bousso's entropic N-bound). One important application of NUT-charged spaces is to construct higher dimensional generalisations of Kaluza-Klein magnetic monopoles, generalising the known 5-dimensional Kaluza-Klein soliton. Another interesting application involves a study of time-dependent higher-dimensional bubbles-of-nothing generated from NUT-charged solutions. We use them to test the AdS/CFT conjecture as well as to generate, by using stringy Hopf-dualities, new interesting time-dependent solutions in string theory. Finally, we construct and study new NUT-charged solutions in higher-dimensional Einstein-Maxwell theories, generalising the known Reissner-Nordstrom solutions.

The Early Years: Blowing Bubbles

ERIC Educational Resources Information Center

Ashbrook, Peggy

2016-01-01

Blowing bubbles is not only a favorite summer activity for young children. Studying bubbles that are grouped together, or "foam," is fun for children and fascinating to many real-world scientists. Foam is widely used--from the bedroom (mattresses) to outer space (insulating panels on spacecraft). Bubble foam can provide children a…

Thermal conductivity of rigid foam insulations for aerospace vehicles

NASA Astrophysics Data System (ADS)

Barrios, M.; Van Sciver, S. W.

2013-05-01

The present work describes measurements of the effective thermal conductivity of NCFI 24-124 foam, a spray-on foam insulation used formerly on the Space Shuttle external fuel tank. A novel apparatus to measure the effective thermal conductivity of rigid foam at temperatures ranging from 20 K to 300 K was developed and used to study three samples of NCFI 24-124 foam insulation. In preparation for measurement, the foam samples were either treated with a uniquely designed moisture absorption apparatus or different residual gases to study their impact on the effective thermal conductivity of the foam. The resulting data are compared to other measurements and mathematical models reported in the literature.

Orbital foamed material extruder

NASA Technical Reports Server (NTRS)

Tucker, Dennis S. (Inventor)

2009-01-01

This invention is a process for producing foamed material in space comprising the steps of: rotating the material to simulate the force of gravity; heating the rotating material until it is molten; extruding the rotating, molten material; injecting gas into the extruded, rotating, molten material to produce molten foamed material; allowing the molten foamed material to cool to below melting temperature to produce the foamed material. The surface of the extruded foam may be heated to above melting temperature and allowed to cool to below melting temperature. The extruded foam may also be cut to predetermined length. The starting material may be metal or glass. Heating may be accomplished by electrical heating elements or by solar heating.

Cryogenic Moisture Analysis of Spray-On Foam Insulation (SOFI)

NASA Technical Reports Server (NTRS)

2008-01-01

The NASA Cryogenics Test Laboratory at Kennedy Space Center conducted long-term testing of SOFI materials under actual-use cryogenic conditions. The lab tested NCFI 24-124 (acreage foam), BX-265 (close-out foam, including intertank flange and bipod areas), and a potential alternate material, NCFI 27-68 (acreage foam with the flame retardant removed). Specimens of all three materials were placed at a site that simulated aging (the Vehicle Assembly Building [VAB]) and a site that simulated weathering (Atmospheric Exposure Test Site [beach site]). After aging/ weathering intervals of 3, 6, and 12 months, the samples were retrieved and tested for their ability to absorb moisture under conditions similar to those experienced by the Space Shuttle External Tank (ET) during the loading of cryogenic propellants.

Manual Fire Suppression Methods on Typical Machinery Space Spray Fires

DTIC Science & Technology

1990-07-31

Aqueous Film Forming Foam Manuscnpt approved April 25, 1990. ( AFFF ), has been incorporated in machinery space fire protection systems to...distribution unlimited. 13. ABSTRACT (Maximum 200 words) A series of tests was conducted to evaluate the effectiveness of Aqueous Film Forming Foami ( AFFF ...machinery space fire protection systems to control running fuel and fuel spray fires (PKP side of TAFES), and bilge fires ( aqueous film forming foam

Shape-memory NiTi foams produced by replication of NaCl space-holders.

PubMed

Bansiddhi, A; Dunand, D C

2008-11-01

NiTi foams were created with a structure (32-36% open pores 70-400 microm in size) and mechanical properties (4-25 GPa stiffness, >1000 MPa compressive strength, >42% compressive ductility, and shape-memory strains up to 4%) useful for bone implant applications. A mixture of NiTi and NaCl powders was hot-isostatically pressed at 950 and 1065 degrees C and the NaCl phase was then dissolved in water. The resulting NiTi foams show interconnected pores that replicate the shape and size of the NaCl powders, indicating that NiTi powders densified significantly before NaCl melted at 801 degrees C. Densifying NiTi or other metal powders above the melting point of the space-holder permits the use of NaCl, with the following advantages compared with higher-melting, solid space-holders such as oxides and fluorides used to date: (i) no temperature limit for densification; (ii) lower cost; (iii) greater flexibility in powder (and thus pore) shape; (iv) faster dissolution; (v) reduced metal corrosion during dissolution; (vi) lower toxicity if space-holder residues remain in the foam.

Experimental study of moisture uptake of polyurethane foam subjected to a heat sink below 30 K

NASA Astrophysics Data System (ADS)

Zhang, X. B.; Chen, J. Y.; Gan, Z. H.; Qiu, L. M.; Zhang, K. H.; Yang, R. P.; Ma, X. J.; Liu, Z. H.

2014-01-01

Rigid closed-cell foam is widely used to thermally insulate liquid hydrogen and oxygen tanks of space launch vehicles due to its lightweight, mechanical strength and thermal-insulating performance. Up to now, little information is available on the intrusion of moisture into the foam that subjects one side to liquid hydrogen temperatures and the other side to room temperatures and high relative humidity. A novel cryogenic moisture uptake apparatus has been designed and fabricated to measure the moisture uptake into the polyurethane foam. For safety and convenience, two identical single-stage pulse tube cryocoolers instead of liquid hydrogen are used to cool one side of the foam specimen to the lowest temperature of 26 K. Total of eight specimens in three groups, according to whether there is a butt-joint or weathering period, are tested respectively for both 5 h and 9 h. The additional weight due to moisture uptake of the foam for the 26 K cases is compared to previous measurements at 79 K. The results are instructive for the applications of foam to the insulation of liquid hydrogen tanks in space launch vehicles.

Flexible Foam Protection Materials for Constellation Space Suit Element Portable Life Support Subsystem Packaging Study

NASA Technical Reports Server (NTRS)

Tang, Henry H.; Orndoff, Evelyne S.; Thomas, Gretchen A.

2009-01-01

This paper discusses the effort in evaluating and selecting a light weight impact protection material for the Constellation Space Suit Element (CSSE) Portable Life Support Subsystem (PLSS) conceptual packaging study. A light weight material capable of holding and protecting the components inside the PLSS is required to demonstrate the viability of the flexible PLSS packaging concept. The material needs to distribute, dissipate, and absorb the impact energy of the PLSS falling on the lunar surface. It must also be very robust and function in the extreme lunar thermal vacuum environment for up to one hundred Extravehicular Activity (EVA) missions. This paper documents the performance requirements for selecting a foam protection material, and the methodologies for evaluating commercial off-the-shelf (COTS) foam protection materials. It also presents the materials properties test results and impact drop test results of the various foam materials evaluated in the study. The findings from this study suggest that a foam based flexible protection system is a viable solution for PLSS packaging. However, additional works are needed to optimize COTS foam properties or to develop a composite foam system that will meet all the performance requirements for the CSSE PLSS flexible packaging.

Electrical conductivity of quasi-two-dimensional foams.

PubMed

Yazhgur, Pavel; Honorez, Clément; Drenckhan, Wiebke; Langevin, Dominique; Salonen, Anniina

2015-04-01

Quasi-two-dimensional (quasi-2D) foams consist of monolayers of bubbles squeezed between two narrowly spaced plates. These simplified foams have served successfully in the past to shed light on numerous issues in foam physics. Here we consider the electrical conductivity of such model foams. We compare experiments to a model which we propose, and which successfully relates the structural and the conductive properties of the foam over the full range of the investigated liquid content. We show in particular that in the case of quasi-2D foams the liquid in the nodes needs to be taken into account even at low liquid content. We think that these results may provide different approaches for the characterization of foam properties and for the in situ characterization of the liquid content of foams in confining geometries, such as microfluidics.

Numerical Evaluation of Mode 1 Stress Intensity Factor as a Function of Material Orientation For BX-265 Foam Insulation Material

NASA Technical Reports Server (NTRS)

Knudsen, Erik; Arakere, Nagaraj K.

2006-01-01

Foam; a cellular material, is found all around us. Bone and cork are examples of biological cell materials. Many forms of man-made foam have found practical applications as insulating materials. NASA uses the BX-265 foam insulation material on the external tank (ET) for the Space Shuttle. This is a type of Spray-on Foam Insulation (SOFI), similar to the material used to insulate attics in residential construction. This foam material is a good insulator and is very lightweight, making it suitable for space applications. Breakup of segments of this foam insulation on the shuttle ET impacting the shuttle thermal protection tiles during liftoff is believed to have caused the space shuttle Columbia failure during re-entry. NASA engineers are very interested in understanding the processes that govern the breakup/fracture of this complex material from the shuttle ET. The foam is anisotropic in nature and the required stress and fracture mechanics analysis must include the effects of the direction dependence on material properties. Material testing at NASA MSFC has indicated that the foam can be modeled as a transversely isotropic material. As a first step toward understanding the fracture mechanics of this material, we present a general theoretical and numerical framework for computing stress intensity factors (SIFs), under mixed-mode loading conditions, taking into account the material anisotropy. We present mode I SIFs for middle tension - M(T) - test specimens, using 3D finite element stress analysis (ANSYS) and FRANC3D fracture analysis software, developed by the Cornel1 Fracture Group. Mode I SIF values are presented for a range of foam material orientations. Also, NASA has recorded the failure load for various M(T) specimens. For a linear analysis, the mode I SIF will scale with the far-field load. This allows us to numerically estimate the mode I fracture toughness for this material. The results represent a quantitative basis for evaluating the strength and fracture properties of anisotropic foam insulation material.

Parametric study of graphite foam fins and application in heat exchangers

NASA Astrophysics Data System (ADS)

Collins, Michael

This thesis focuses on the simulation and experimental studies of finned graphite foam extended surfaces to test their heat transfer characteristics and potential applications in condensers. Different fin designs were developed to conduct a parametric study on the thermal effectiveness with respect to thickness, spacing and fin offset angle. Each fin design was computationally simulated to estimate the heat transfer under specific conditions. The simulations showed that this optimal fin configuration could conduct more than 297% the amount of thermal energy as compared to straight aluminum fins. Graphite foam fins were then implemented into a simulation of the condenser system. The condenser was simulated with six different orientations of baffles to examine the incoming vapor and resulting two-phase flow patterns. The simulations showed that using both horizontal and vertical baffling provided the configuration with the highest heat transfer and minimized the bypass regions where the vapor would circumvent the graphite foam. This baffle configuration increased the amount of vapor flow through the inner graphite fins and cold water pipes, which gave this configuration the highest heat transfer. The results from experimental tests using the condenser system confirmed that using three baffles will increase performance consistent with the simulation results. The experimental data showed that the condenser using graphite foam had five times the heat transfer compared to the condenser using only aluminum fins. Incorporating baffles into the condenser using graphite foam enabled this system to conduct nearly ten times more heat transfer than the condenser system which only had aluminum fins without baffles. The results from this research indicate that graphite foam is a far superior material heat transfer enhancement material for heat transfer compared to aluminum used as an extended surface. The longitudinal and horizontal baffles incorporated into the condenser system greatly enhanced the heat transfer because of the increased interaction with the porous graphite foam fins.

Quantum group spin nets: Refinement limit and relation to spin foams

NASA Astrophysics Data System (ADS)

Dittrich, Bianca; Martin-Benito, Mercedes; Steinhaus, Sebastian

2014-07-01

So far spin foam models are hardly understood beyond a few of their basic building blocks. To make progress on this question, we define analogue spin foam models, so-called "spin nets," for quantum groups SU(2)k and examine their effective continuum dynamics via tensor network renormalization. In the refinement limit of this coarse-graining procedure, we find a vast nontrivial fixed-point structure beyond the degenerate and the BF phase. In comparison to previous work, we use fixed-point intertwiners, inspired by Reisenberger's construction principle [M. P. Reisenberger, J. Math. Phys. (N.Y.) 40, 2046 (1999)] and the recent work [B. Dittrich and W. Kaminski, arXiv:1311.1798], as the initial parametrization. In this new parametrization fine-tuning is not required in order to flow to these new fixed points. Encouragingly, each fixed point has an associated extended phase, which allows for the study of phase transitions in the future. Finally we also present an interpretation of spin nets in terms of melonic spin foams. The coarse-graining flow of spin nets can thus be interpreted as describing the effective coupling between two spin foam vertices or space time atoms.

Radiative Kähler moduli stabilization

NASA Astrophysics Data System (ADS)

Kobayashi, Tatsuo; Omoto, Naoya; Otsuka, Hajime; Tatsuishi, Takuya H.

2018-05-01

We propose a new type of Kähler moduli stabilization mechanisms in type IIB superstring theory on Calabi-Yau manifolds with the positive Euler number. The overall Kähler modulus can be perturbatively stabilized by radiative corrections due to sparticles. Its minimum is the anti-de Sitter vacuum, where supersymmetry is broken. We can uplift it to the de Sitter vacuum by introducing anti-D-branes, keeping the modulus stabilized. Although our numerical results depend on the choice of the cutoff scale and degeneracies of sparticles, at any rate there exist the parameter spaces where the masses of Kaluza-Klein and stringy modes are larger than the cutoff scale. Furthermore, this stabilization scenario predicts an ultralight axion.

46 CFR 170.245 - Foam flotation material.

Code of Federal Regulations, 2014 CFR

2014-10-01

... submerged to its margin line. (4) The effective buoyancy at the end of the submergence test must be used as the buoyancy credit; however, in no case will a credit greater than 55 lbs per cubic foot (881... accommodate the buoyancy of the foam. (6) Piping and cables must not pass through foamed spaces unless they...

46 CFR 170.245 - Foam flotation material.

Code of Federal Regulations, 2012 CFR

2012-10-01

... submerged to its margin line. (4) The effective buoyancy at the end of the submergence test must be used as the buoyancy credit; however, in no case will a credit greater than 55 lbs per cubic foot (881... accommodate the buoyancy of the foam. (6) Piping and cables must not pass through foamed spaces unless they...

46 CFR 170.245 - Foam flotation material.

Code of Federal Regulations, 2013 CFR

2013-10-01

... submerged to its margin line. (4) The effective buoyancy at the end of the submergence test must be used as the buoyancy credit; however, in no case will a credit greater than 55 lbs per cubic foot (881... accommodate the buoyancy of the foam. (6) Piping and cables must not pass through foamed spaces unless they...

Assessment of Technologies for the Space Shuttle External Tank Thermal Protection System and Recommendations for Technology Improvement. Part 2; Structural Analysis Technologies and Modeling Practices

NASA Technical Reports Server (NTRS)

Knight, Norman F., Jr.; Nemeth, Michael P.; Hilburger, Mark W.

2004-01-01

A technology review and assessment of modeling and analysis efforts underway in support of a safe return to flight of the thermal protection system (TPS) for the Space Shuttle external tank (ET) are summarized. This review and assessment effort focuses on the structural modeling and analysis practices employed for ET TPS foam design and analysis and on identifying analysis capabilities needed in the short-term and long-term. The current understanding of the relationship between complex flight environments and ET TPS foam failure modes are reviewed as they relate to modeling and analysis. A literature review on modeling and analysis of TPS foam material systems is also presented. Finally, a review of modeling and analysis tools employed in the Space Shuttle Program is presented for the ET TPS acreage and close-out foam regions. This review includes existing simplified engineering analysis tools are well as finite element analysis procedures.

Space Shuttle Atlantis' external tank repairs from Hail Damage

NASA Image and Video Library

2007-04-09

In the Vehicle Assembly Building, markers show the hail damage being repaired on the external tank of Space Shuttle Atlantis. The white hole with a red circle around it is a hole prepared for molding and material application. The red material is sealant tape so the mold doesn't leak when the foam rises against the mold. The white/ translucent square mold is an area where the foam has been applied and the foam has risen and cured against the mold surface. The area will be de-molded and sanded flush the with adjacent area. In late February, Atlantis' external tank received hail damage during a severe thunderstorm that passed through the Kennedy Space Center Launch Complex 39 area. The hail caused visible divots in the giant tank's foam insulation as well as minor surface damage to about 26 heat shield tiles on the shuttle's left wing. The March launch was postponed and has not yet been rescheduled due to the repair process.

KSC-07pd0885

NASA Image and Video Library

2007-04-13

KENNEDY SPACE CENTER, FLA. -- In the Vehicle Assembly Building, markers show the hail damage being repaired on the external tank of Space Shuttle Atlantis. The white hole with a red circle around it is a hole prepared for molding and material application. The red material is sealant tape so the mold doesn't leak when the foam rises against the mold. The white/translucent square mold is an area where the foam has been applied and the foam has risen and cured against the mold surface. The area will be de-molded and sanded flush with the adjacent area. In late February, Atlantis' external tank received hail damage during a severe thunderstorm that passed through the Kennedy Space Center Launch Complex 39 area. The hail caused visible divots in the giant tank's foam insulation as well as minor surface damage to about 26 heat shield tiles on the shuttle's left wing. The launch now is targeted for June 8. Photo credit: NASA/George Shelton

KSC-07pd0848

NASA Image and Video Library

2007-04-09

KENNEDY SPACE CENTER, FLA. -- In the Vehicle Assembly Building, markers show the hail damage being repaired on the external tank of Space Shuttle Atlantis. The white hole with a red circle around it is a hole prepared for molding and material application. The red material is sealant tape so the mold doesn't leak when the foam rises against the mold. The white/translucent square mold is an area where the foam has been applied and the foam has risen and cured against the mold surface. The area will be de-molded and sanded flush the with adjacent area. In late February, Atlantis' external tank received hail damage during a severe thunderstorm that passed through the Kennedy Space Center Launch Complex 39 area. The hail caused visible divots in the giant tank's foam insulation as well as minor surface damage to about 26 heat shield tiles on the shuttle's left wing. The March launch was postponed and has not yet been rescheduled due to the repair process. Photo credit: NASA/George Shelton

Application of Terahertz Imaging and Backscatter Radiography to Space Shuttle Foam Inspection

NASA Technical Reports Server (NTRS)

Ussery, Warren

2008-01-01

Two state of the art technologies have been developed for External Fuel Tank foam inspections. Results of POD tests have shown Backscatter Radiography and Terahertz imaging detect critical defects with no false positive issue. These techniques are currently in use on the External Tank program as one component in the foam quality assurance program.

KSC-06pd0685

NASA Image and Video Library

2006-04-18

KENNEDY SPACE CENTER, FLA. -- Lockheed Martin technicians in the Vehicle Assembly Building at NASA's Kennedy Space Center apply new foam over the manhole cover on the lower end of external tank No. 119. The manhole was removed to access the area where the tank's four liquid hydrogen engine cutoff sensors were replaced. Once reinstalled, the manhole required new foam to be applied. The tank is being prepared to launch Space Shuttle Discovery on mission STS-121 in July. Photo credit: NASA/Jim Grossmann

Microstructure and Mechanical Behavior of Amorphous Al-Cu-Ti Metal Foams Synthesized by Spark Plasma Sintering

NASA Astrophysics Data System (ADS)

Li, Maoyuan; Lu, Lin; Dai, Zhen; Hong, Yiqiang; Chen, Weiwei; Zhang, Yuping; Qiao, Yingjie

Amorphous Al-Cu-Ti metal foams were prepared by spark plasma sintering (SPS) process with the diameter of 10mm. The SPS process was conducted at the pressure of 200 and 300MPa with the temperature of 653-723K, respectively. NaCl was used as the space-holder, forming almost separated pores with the porosity of 65 vol%. The microstructure and mechanical behavior of the amorphous Al-Cu-Ti metal foams were systematically investigated. The results show that the crystallinity increased at elevated temperatures. The effect of pressure and holding time on the crystallization was almost negligible. The intermetallic compounds, i.e. Al-Ti, Al-Cu and Al-Cu-Ti were identified from X-ray diffraction (XRD) patterns. It was found that weak adhesion and brittle intermetallic compounds reduced the mechanical properties, while lower volume fraction and smaller size of NaCl powders improved the mechanical properties.

Characterization of Solid Polymers, Ceramic Gap Filler, and Closed-Cell Polymer Foam Using Low-Load Test Methods

NASA Technical Reports Server (NTRS)

Herring, Helen M.

2008-01-01

Various solid polymers, polymer-based composites, and closed-cell polymer foam are being characterized to determine their mechanical properties, using low-load test methods. The residual mechanical properties of these materials after environmental exposure or extreme usage conditions determines their value in aerospace structural applications. In this experimental study, four separate polymers were evaluated to measure their individual mechanical responses after thermal aging and moisture exposure by dynamic mechanical analysis. A ceramic gap filler, used in the gaps between the tiles on the Space Shuttle, was also tested, using dynamic mechanical analysis to determine material property limits during flight. Closed-cell polymer foam, used for the Space Shuttle External Tank insulation, was tested under low load levels to evaluate how the foam's mechanical properties are affected by various loading and unloading scenarios.

Hypervelocity Impact Evaluation of Metal Foam Core Sandwich Structures

NASA Technical Reports Server (NTRS)

Yasensky, John; Christiansen, Eric L.

2007-01-01

A series of hypervelocity impact (HVI) tests were conducted by the NASA Johnson Space Center (JSC) Hypervelocity Impact Technology Facility (HITF) [1], building 267 (Houston, Texas) between January 2003 and December 2005 to test the HVI performance of metal foams, as compared to the metal honeycomb panels currently in service. The HITF testing was conducted at the NASA JSC White Sands Testing Facility (WSTF) at Las Cruces, New Mexico. Eric L. Christiansen, Ph.D., and NASA Lead for Micro-Meteoroid Orbital Debris (MMOD) Protection requested these hypervelocity impact tests as part of shielding research conducted for the JSC Center Director Discretionary Fund (CDDF) project. The structure tested is a metal foam sandwich structure; a metal foam core between two metal facesheets. Aluminum and Titanium metals were tested for foam sandwich and honeycomb sandwich structures. Aluminum honeycomb core material is currently used in Orbiter Vehicle (OV) radiator panels and in other places in space structures. It has many desirable characteristics and performs well by many measures, especially when normalized by density. Aluminum honeycomb does not perform well in Hypervelocity Impact (HVI) Testing. This is a concern, as honeycomb panels are often exposed to space environments, and take on the role of Micrometeoroid / Orbital Debris (MMOD) shielding. Therefore, information on possible replacement core materials which perform adequately in all necessary functions of the material would be useful. In this report, HVI data is gathered for these two core materials in certain configurations and compared to gain understanding of the metal foam HVI performance.

The effect of alumina particles on the microstructural and mechanical properties of copper foams fabricated by space-holder method

NASA Astrophysics Data System (ADS)

Salvo, C.; Aguilar, C.; Lascano, S.; Pérez, L.; López, M.; Mangalaraja, R. V.

2018-05-01

The copper foam is an interesting field of research because of its several advantages as an engineering material. Powder metallurgy presents an alternative route to obtain a porous structure with high strength to weight ratio and functional properties. The viability of processing copper foam separately with two different space-holders such as ammonium hydrogen carbonate (NH4HCO3) and sodium chloride (NaCl) of 50 vol% was studied. The green compacts obtained under 200 MPa were sintered at different cycles for the complete removal of space-holder. The sintered foams were characterized by optical microscopy (OM), scanning electron microscopy (SEM) and uniaxial testing machine (UTM) to study their structural features and compressive strength, respectively. The results showed that NaCl particles were the best alternative to obtain a porous structure, hence two different sizes (1 and 0.01 μm) of alumina (Al2O3) particles with 2, 4 and 6 vol% were used to fabricate copper foams. As a result, a bimodal structure consisting of macro and micropores with a highly interconnected porosity was achieved. In addition, the smaller size alumina particles promoted a higher density of pores, however, the compressive strength was reduced for the higher volume fraction of alumina particles.

Influence of Syringe Volume on Foam Stability in Sclerotherapy for Varicose Vein Treatment.

PubMed

Bai, Taoping; Jiang, Wentao; Fan, Yubo

2018-05-01

Despite the popularity of sclerotherapy for treating varicose veins, it still exhibits various problems, such as pulmonary embolism, deep-vein thrombosis, phlebitis, and visual disorders. To investigate syringe volume influence on foam stability, obtain the foam decay rule, and provide a reference for clinics. Five types of syringes are used to prepare foam at room temperature with various liquid-gas ratios. Foam decay process experiments were performed 5 times and recorded by video. The stability indices used include drainage time, half-life, bubble diameter, bubble surface density, and drainage rate. The 30 and 2-mL syringes, respectively, recorded the highest and lowest drainage speeds. Foam drainage time and half-life, differences varied between 15 and 70 seconds, and 20 and 100 seconds, respectively. Foam bubble diameters were distributed over 0.1 to 2.0 mm with roughly 200 to 700 bubbles per square centimeter. Increased syringe volume causes the bubble diameter to increase. Thus, foam dispersion increases and foam half-life decreases; hence, foam becomes unstable. It is, thus, better to use a small syringe several times to prepare foam in clinics using segmented injections.

KSC-06pd0684

NASA Image and Video Library

2006-04-18

KENNEDY SPACE CENTER, FLA. -- Lockheed Martin technicians in the Vehicle Assembly Building at NASA's Kennedy Space Center begin to apply new foam over the manhole cover on the lower end of external tank No. 119. The manhole was removed to access the area where the tank's four liquid hydrogen engine cutoff sensors were replaced. Once reinstalled, the manhole required new foam to be applied. The tank is being prepared to launch Space Shuttle Discovery on mission STS-121 in July. Photo credit: NASA/Jim Grossmann

KSC-06pd0682

NASA Image and Video Library

2006-04-18

KENNEDY SPACE CENTER, FLA. -- Lockheed Martin technicians in the Vehicle Assembly Building at NASA's Kennedy Space Center prepare for the application of new foam over the manhole cover on the lower end of external tank No. 119. The manhole was removed to access the area where the tank's four liquid hydrogen engine cutoff sensors were replaced. Once reinstalled, the manhole required new foam to be applied. The tank is being prepared to launch Space Shuttle Discovery on mission STS-121 in July. Photo credit: NASA/Jim Grossmann

KSC-06pd0683

NASA Image and Video Library

2006-04-18

KENNEDY SPACE CENTER, FLA. -- Lockheed Martin technicians in the Vehicle Assembly Building at NASA's Kennedy Space Center prepare for the application of new foam over the manhole cover on the lower end of external tank No. 119. The manhole was removed to access the area where the tank's four liquid hydrogen engine cutoff sensors were replaced. Once reinstalled, the manhole required new foam to be applied. The tank is being prepared to launch Space Shuttle Discovery on mission STS-121 in July. Photo credit: NASA/Jim Grossmann

Lagrangian approach to the Barrett-Crane spin foam model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bonzom, Valentin; Laboratoire de Physique, ENS Lyon, CNRS UMR 5672, 46 Allee d'Italie, 69007 Lyon; Livine, Etera R.

2009-03-15

We provide the Barrett-Crane spin foam model for quantum gravity with a discrete action principle, consisting in the usual BF term with discretized simplicity constraints which in the continuum turn topological BF theory into gravity. The setting is the same as usually considered in the literature: space-time is cut into 4-simplices, the connection describes how to glue these 4-simplices together and the action is a sum of terms depending on the holonomies around each triangle. We impose the discretized simplicity constraints on disjoint tetrahedra and we show how the Lagrange multipliers distort the parallel transport and the correlations between neighboringmore » simplices. We then construct the discretized BF action using a noncommutative * product between SU(2) plane waves. We show how this naturally leads to the Barrett-Crane model. This clears up the geometrical meaning of the model. We discuss the natural generalization of this action principle and the spin foam models it leads to. We show how the recently introduced spin foam fusion coefficients emerge with a nontrivial measure. In particular, we recover the Engle-Pereira-Rovelli spin foam model by weakening the discretized simplicity constraints. Finally, we identify the two sectors of Plebanski's theory and we give the analog of the Barrett-Crane model in the nongeometric sector.« less

Remarks on entanglement entropy in string theory

NASA Astrophysics Data System (ADS)

Balasubramanian, Vijay; Parrikar, Onkar

2018-03-01

Entanglement entropy for spatial subregions is difficult to define in string theory because of the extended nature of strings. Here we propose a definition for bosonic open strings using the framework of string field theory. The key difference (compared to ordinary quantum field theory) is that the subregion is chosen inside a Cauchy surface in the "space of open string configurations." We first present a simple calculation of this entanglement entropy in free light-cone string field theory, ignoring subtleties related to the factorization of the Hilbert space. We reproduce the answer expected from an effective field theory point of view, namely a sum over the one-loop entanglement entropies corresponding to all the particle-excitations of the string, and further show that the full string theory regulates ultraviolet divergences in the entanglement entropy. We then revisit the question of factorization of the Hilbert space by analyzing the covariant phase-space associated with a subregion in Witten's covariant string field theory. We show that the pure gauge (i.e., BRST exact) modes in the string field become dynamical at the entanglement cut. Thus, a proper definition of the entropy must involve an extended Hilbert space, with new stringy edge modes localized at the entanglement cut.

KSC-08pd0078

NASA Image and Video Library

2008-01-23

KENNEDY SPACE CENTER, FLA. -- Quality inspectors with NASA and Lockheed Martin examine a red-line drawing of foam placement on space shuttle Atlantis's external tank (in front of them) to verify the foam insulation that was reapplied. The foam covers the feed-through engine cut-off, or ECO, sensor connector. The foam was removed to enable engineers to remove and replace the ECO sensor connector on the tank. The feed-through connector passes the wires from the inside of the tank to the outside. Results of a tanking test on Dec. 18 pointed to an open circuit in the feed-through connector wiring, which is located at the base of the tank. The pins in the replacement connector were precisely soldered to create a connection that allows sensors inside the tank to send signals to the computers onboard Atlantis. The repair work was done on Atlantis while the shuttle has been on Launch Pad 39A at NASA's Kennedy Space Center. The launch date for the shuttle's STS-122 mission has now been targeted for Feb. 7. Photo credit: NASA/Cory Husten

KSC-08pd0077

NASA Image and Video Library

2008-01-23

KENNEDY SPACE CENTER, FLA. -- Quality inspectors with NASA and Lockheed Martin examine a red-line drawing of foam placement on space shuttle Atlantis's external tank (in front of them) to verify the foam insulation that was reapplied. The foam covers the feed-through engine cut-off, or ECO, sensor connector. The foam was removed to enable engineers to remove and replace the ECO sensor connector on the tank. The feed-through connector passes the wires from the inside of the tank to the outside. Results of a tanking test on Dec. 18 pointed to an open circuit in the feed-through connector wiring, which is located at the base of the tank. The pins in the replacement connector were precisely soldered to create a connection that allows sensors inside the tank to send signals to the computers onboard Atlantis. The repair work was done on Atlantis while the shuttle has been on Launch Pad 39A at NASA's Kennedy Space Center. The launch date for the shuttle's STS-122 mission has now been targeted for Feb. 7. Photo credit: NASA/Cory Husten

KSC-08pd0080

NASA Image and Video Library

2008-01-23

KENNEDY SPACE CENTER, FLA. -- Quality inspectors with NASA and Lockheed Martin examine a red-line drawing of foam placement on space shuttle Atlantis's external tank (in front of them) to verify the foam insulation that was reapplied. The foam covers the feed-through engine cut-off, or ECO, sensor connector. The foam was removed to enable engineers to remove and replace the ECO sensor connector on the tank. The feed-through connector passes the wires from the inside of the tank to the outside. Results of a tanking test on Dec. 18 pointed to an open circuit in the feed-through connector wiring, which is located at the base of the tank. The pins in the replacement connector were precisely soldered to create a connection that allows sensors inside the tank to send signals to the computers onboard Atlantis. The repair work was done on Atlantis while the shuttle has been on Launch Pad 39A at NASA's Kennedy Space Center. The launch date for the shuttle's STS-122 mission has now been targeted for Feb. 7. Photo credit: NASA/Cory Husten

KSC-08pd0079

NASA Image and Video Library

2008-01-23

KENNEDY SPACE CENTER, FLA. -- Quality inspectors with NASA and Lockheed Martin examine a red-line drawing of foam placement on space shuttle Atlantis's external tank (in front of them) to verify the foam insulation that was reapplied. The foam covers the feed-through engine cut-off, or ECO, sensor connector. The foam was removed to enable engineers to remove and replace the ECO sensor connector on the tank. The feed-through connector passes the wires from the inside of the tank to the outside. Results of a tanking test on Dec. 18 pointed to an open circuit in the feed-through connector wiring, which is located at the base of the tank. The pins in the replacement connector were precisely soldered to create a connection that allows sensors inside the tank to send signals to the computers onboard Atlantis. The repair work was done on Atlantis while the shuttle has been on Launch Pad 39A at NASA's Kennedy Space Center. The launch date for the shuttle's STS-122 mission has now been targeted for Feb. 7. Photo credit: NASA/Cory Husten

Higher order string effects and the properties of the Pomeron

DOE PAGES

Kharzeev, Dmitri; Shuryak, Edward; Zahed, Ismail

2018-01-18

In this paper, we revisit the description of the Pomeron within the effective string theory of QCD. Using a string duality relation, we show how the static potential maps onto the high-energy scattering amplitude that exhibits the Pomeron behavior. Besides the Pomeron intercept and slope, new additional terms stemming from the higher order string corrections are shown to affect both the growth of the nucleon’s size at high energies and its profile in impact parameter space. The stringy description also allows for an odderon that only disappears in critical dimension. Lastlyl, some of the Pomeron’s features that emerge within themore » effective string description can be studied at the future EIC collider.« less

Quantization of Non-Lagrangian Systems

NASA Astrophysics Data System (ADS)

Kochan, Denis

A novel method for quantization of non-Lagrangian (open) systems is proposed. It is argued that the essential object, which provides both classical and quantum evolution, is a certain canonical two-form defined in extended velocity space. In this setting classical dynamics is recovered from the stringy-type variational principle, which employs umbilical surfaces instead of histories of the system. Quantization is then accomplished in accordance with the introduced variational principle. The path integral for the transition probability amplitude (propagator) is rearranged to a surface functional integral. In the standard case of closed (Lagrangian) systems the presented method reduces to the standard Feynman's approach. The inverse problem of the calculus of variation, the problem of quantization ambiguity and the quantum mechanics in the presence of friction are analyzed in detail.

Finite Element Modeling of Deployment, and Foam Rigidization of Struts and Quarter Scale Shooting Star Experiment

NASA Technical Reports Server (NTRS)

Leigh, Larry, Jr.

2002-01-01

Inflated cylindrical struts constructed of kapton polyimide film and rigidized with foam have considerable practical application and potential for use as components of inflatable concentrator assemblies, antenna structures and space power systems, Because of their importance, it is of great interest to characterize the dynamic behavior of these components and structures both experimentally and analytically. It is very helpful to take a building-block approach to modeling and understanding inflatable assemblies by first investigating in detail the behavior of the components such as the struts. The foam material used for rigidization of such cylinders has varying modulus, which is a function of different factors, such as density of the foam. Thus, the primary motivation of the tests and analytical modeling efforts was to determine and understand the response of foam-rigidized cylinders for different densities, sizes, and construction methods, In recent years, inflatable structures have been the subject of renewed interest for space applications such as communications antennae, solar thermal propulsion, and space solar power. A major advantage of using inflatable structures in space is that they are extremely lightweight. This makes inflatables a perfect match for solar thermal propulsion because of the low thrust levels available. An obvious second advantage is on-orbit deployability and subsequent space savings in launch configuration. It can be seen that inflatable cylindrical struts and torus are critical components of structural assemblies. In view of this importance, structural dynamic and static behaviors of typical rigidized polyimide struts are investigated in this paper. The paper will focus on the finite element models that were used to model the behavior of the complete solar collector structure, and the results that they provided, as compared to test data.

KSC-07pd1082

NASA Image and Video Library

2007-05-09

KENNEDY SPACE CENTER, FLA. -- In NASA Kennedy Space Center's Vehicle Assembly Building, technicians place a piece of foam on the side of Atlantis' nose cone to rest the sander while they make adjustments. In late February, Atlantis' external tank received hail damage during a severe thunderstorm that passed through the Kennedy Space Center Launch Complex 39 area. The hail caused visible divots in the giant tank's foam insulation as well as minor surface damage to about 26 heat shield tiles on the shuttle's left wing. The launch of Space Shuttle Atlantis on mission STS-117 now is targeted for June 8. Photo credit: NASA/Jack Pfaller

DebriSat Hypervelocity Impact Test

DTIC Science & Technology

2015-08-01

material. The foam was also color coded to assist in determining the location of various loose foam pieces found posttest . Details on the layer... pretest and posttest shots. AEDC-TR-15-S-2 23 Statement A: Approved by public release; distribution unlimited. APPENDIX B. SOFT CATCH FOAM CONFIGURATION ...spacecraft. One of the major hazards is hypervelocity impacts from uncontrolled, man-made space debris. Arnold Engineering Development Complex

46 CFR 34.17-90 - Installations contracted for prior to January 1, 1962-T/ALL.

Code of Federal Regulations, 2011 CFR

2011-10-01

... FIREFIGHTING EQUIPMENT Fixed Foam Extinguishing Systems, Details § 34.17-90 Installations contracted for prior... § 34.17-5 and § 34.17-25. A 6-inch blanket of foam in 3 minutes for machinery spaces and pumprooms will... tank, it shall be so designed and arranged as to spread a blanket of foam over the entire liquid...

46 CFR 34.17-90 - Installations contracted for prior to January 1, 1962-T/ALL.

Code of Federal Regulations, 2010 CFR

2010-10-01

... FIREFIGHTING EQUIPMENT Fixed Foam Extinguishing Systems, Details § 34.17-90 Installations contracted for prior... § 34.17-5 and § 34.17-25. A 6-inch blanket of foam in 3 minutes for machinery spaces and pumprooms will... tank, it shall be so designed and arranged as to spread a blanket of foam over the entire liquid...

A Non-Critical String (Liouville) Approach to Brain Microtubules:. State Vector Reduction, Memory Coding and Capacity

NASA Astrophysics Data System (ADS)

Mavromatos, N. E.; Nanopoulos, D. V.

Microtubule (MT) networks, subneural paracrystalline cytoskeletal structures, seem to play a fundamental role in the neurons. We cast here the complicated MT dynamics in the form of a (1+1)-dimensional noncritical string theory, thus enabling us to provide a consistent quantum treatment of MTs, including enviromental friction effects. We suggest, thus, that the MTs are the microsites, in the brain, for the emergence of stable, macroscopic quantum coherent states, identifiable with the preconscious states. Quantum space-time effects, as described by noncritical string theory, trigger then an organized collapse of the coherent states down to a specific or conscious state. The whole process we estimate to take { O}(1 sec), in excellent agreement with a plethora of experimental/observational findings. The microscopic arrow of time, endemic in noncritical string theory, and apparent here in the self-collapse process, provides a satisfactory and simple resolution to the age-old problem of how the, central to our feelings of awareness, sensation of the progression of time is generated. In addition, the complete integrability of the stringy model for MT we advocate in this work proves sufficient in providing a satisfactory solution to memory coding and capacity. Such features might turn out to be important for a model of the brain as a quantum computer.

Hail damage on Atlantis' external tank is inspected

NASA Image and Video Library

2007-04-13

In the Vehicle Assembly Building, markers show the hail damage being repaired on the external tank of Space Shuttle Atlantis. The white hole with a red circle around it is a hole prepared for molding and material application. The red material is sealant tape so the mold doesn't leak when the foam rises against the mold. The white/ translucent square mold is an area where the foam has been applied and the foam has risen and cured against the mold surface. The area will be de-molded and sanded flush with the adjacent area. In late February, Atlantis' external tank received hail damage during a severe thunderstorm that passed through the Kennedy Space Center Launch Complex 39 area. The hail caused visible divots in the giant tank's foam insulation as well as minor surface damage to about 26 heat shield tiles on the shuttle's left wing. The launch now is targeted for June 8.

X-38 Advanced Sublimator

NASA Technical Reports Server (NTRS)

Dingell, Chuck; Quintana, Clemente; Le, Suy; Hafemalz, David S.; Clark, Mike; Cloutier, Robert

2009-01-01

A document discusses a heat rejection device for transferring heat from a space vehicle by venting water into space through the use of a novel, two-stage water distribution system. The system consists of two different, porous media that stop water-borne contaminants from clogging the system and causing operational failures. Feedwater passes through a small nozzle, then into a porous disk made of sintered stainless steel, and then finally into large-pore aluminum foam. The smaller pore layer of the steel disk controls the pressure drop of the feedwater. The ice forms in the foam layer, and then sublimates, leaving any contaminants behind. The pore-size of the foam is two orders of magnitude larger than the current porous plate sublimators, allowing for a greater tolerance for contaminants. Using metallic fibers in the foam also negates problems with compression seen in the use of poly(tetrafluoroethylene) felt.

Preparation of Microcellular Epoxy Foams through a Limited-Foaming Process: A Contradiction with the Time-Temperature-Transformation Cure Diagram.

PubMed

Wang, Lijun; Zhang, Chun; Gong, Wei; Ji, Yubi; Qin, Shuhao; He, Li

2018-01-01

3D cross-linking networks are generated through chemical reactions between thermosetting epoxy resin and hardener during curing. The curing degree of epoxy material can be increased by increasing curing temperature and/or time. The epoxy material must then be fully cured through a postcuring process to optimize its material characteristics. Here, a limited-foaming method is introduced for the preparation of microcellular epoxy foams (Lim-foams) with improved cell morphology, high thermal expansion coefficient, and good compressive properties. Lim-foams exhibit a lower glass transition temperature (T g ) and curing degree than epoxy foams fabricated through free-foaming process (Fre-foams). Surprisingly, however, the T g of Lim-foams is unaffected by postcuring temperature and time. This phenomenon, which is related to high gas pressure in the bubbles, contradicts that indicated by the time-temperature-transformation cure diagram. High bubble pressure promotes the movement of molecular chains under heating at low temperature and simultaneously suppresses the etherification cross-linking reaction during post-curing. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nondestructive Evaluation of Foam Insulation for the External Tank Return to Flight

NASA Technical Reports Server (NTRS)

Walker, James L.; Richter, Joel D.

2006-01-01

Nondestructive evaluation methods have been developed to identify defects in the foam thermal protection system (TPS) of the Space Shuttle External Tank (ET). Terahertz imaging and backscatter radiography have been brought from prototype lab systems to production hardened inspection tools in just a few years. These methods have been demonstrated to be capable of detecting void type defects under many inches of foam which, if not repaired, could lead to detrimental foam loss. The evolution of these methods from lab tools to implementation on the ET will be discussed.

Improved Sand-Compaction Method for Lost-Foam Metal Casting

NASA Technical Reports Server (NTRS)

Bakhtiyarov, Sayavur I.; Overfelt, Ruel A.

2008-01-01

An improved method of filling a molding flask with sand and compacting the sand around a refractory-coated foam mold pattern has been developed for incorporation into the lost-foam metal-casting process. In comparison with the conventional method of sand filling and compaction, this method affords more nearly complete filling of the space around the refractory-coated foam mold pattern and more thorough compaction of the sand. In so doing, this method enables the sand to better support the refractory coat under metallostatic pressure during filling of the mold with molten metal.

From Planck Constant to Isomorphicity Through Justice Paradox

NASA Astrophysics Data System (ADS)

Hidajatullah-Maksoed, Widastra

2015-05-01

Robert E. Scott in his ``Chaos theory and the Justice Paradox'', William & Mary Law Review, v 35, I 1, 329 (1993) wrotes''...As we approach the 21-st Century, the signs of social disarray are everywhere. Social critics observe the breakdown of core structure - the nuclear family, schools, neighborhoods & political groups''. For completions for ``soliton'' first coined by Morikazu TODA, comparing the ``Soliton on Scott-Russell aqueduct on the Union Canal near Heriot-WATT University, July 12, 1995 to Michael Stock works: ``a Fine WATT-Balance: Determination of Planck constant & Redefinition of Kilogram'', January 2011, we can concludes the inherencies between `chaos' & `soliton'. Further through ``string theory'' from Michio KAKU sought statements from Peter Mayr: Stringy world brane & Exponential hierarchy'', JHEP 11 (2000): ``if the 5-brane is embedded in flat 10-D space time, the 6-D Planck mass on the brane is infinite'' who also describes the relation of isomorphicity & ``string theory'', from whom denotes the smart city. Replace this text with your abstract body. Incredible acknowledgments to HE. Mr. Drs. P. SWANTORO & HE. Mr. Dr-HC Jakob OETAMA.

Materials Assessment of Insulating Foam in the 9977 Shipping Package for Long-Term Storage - Annual Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

McWilliams, A. J.

The 9977 shipping package is being evaluated for long-term storage applications in the K-Area Complex (KAC) with specific focus on the packaging foam material. A rigid closed cell polyurethane foam, LAST-A-FOAM® FR-3716, produced by General Plastics Manufacturing Company is sprayed and expands to fill the void between the inner container and the outer shell of the package. The foam is sealed in this annular space and is not accessible. During shipping and storage, the foam experiences higher than ambient temperatures from the heat generated by nuclear material within the package creating the potential for degradation of the foam. A seriesmore » of experiments is underway to determine the extent of foam degradation. Foam samples of three densities have been aging at elevated temperatures 160 °F, 160 °F + 50% relative humidity (RH), 185 °F, 215 °F, and 250 °F since 2014. Samples were periodically removed and tested. After approximately 80 weeks, samples conditioned at 160 °F, 160 °F + 50% RH, and 185 °F have retained initial property values while samples conditioned at 215 °F have reduced intumescence. Samples conditioned at 250 °F have shown the most degradation, loss of volume, mass, absorbed energy under compression, intumescence, and increased flammability. Based on the initial data, temperatures up to 185 °F have not yet shown an adverse effect on the foam properties and it is recommended that exposure of FR-3716 foam to temperatures in excess of 250 °F be avoided or minimized. Testing will continue beyond the 96 week mark. This will provide additional data to help define the long-term behavior for the lower temperature conditions. Additional testing will be pursued in an attempt to identify transition points (threshold times and temperatures) at the higher temperatures of interest, as well as possible benefits of aging within the relatively oxygen-free environment the foam experiences inside the 9977 shipping package.« less

Advanced Metal Foam Structures for Outer Space

NASA Technical Reports Server (NTRS)

Hanan, Jay; Johnson, William; Peker, Atakan

2005-01-01

A document discusses a proposal to use advanced materials especially bulk metallic glass (BMG) foams in structural components of spacecraft, lunar habitats, and the like. BMG foams, which are already used on Earth in some consumer products, are superior to conventional metal foams: BMG foams have exceptionally low mass densities and high strength-to-weight ratios and are more readily processable into strong, lightweight objects of various sizes and shapes. These and other attractive properties of BMG foams would be exploited, according to the proposal, to enable in situ processing of BMG foams for erecting and repairing panels, shells, containers, and other objects. The in situ processing could include (1) generation of BMG foams inside prefabricated deployable skins that would define the sizes and shapes of the objects thus formed and (2) thermoplastic deformation of BMG foams. Typically, the generation of BMG foams would involve mixtures of precursor chemicals that would be subjected to suitable pressure and temperature schedules. In addition to serving as structural components, objects containing or consisting of BMG foams could perform such functions as thermal management, shielding against radiation, and shielding against hypervelocity impacts of micrometeors and small debris particles.

Orbital fabrication of aluminum foam and apparatus therefore

NASA Technical Reports Server (NTRS)

Tucker, Dennis S. (Inventor)

2010-01-01

A process for producing foamed aluminum in space comprising the steps of: heating aluminum until it is molten; applying the force of gravity to the molten aluminum; injecting gas into the molten aluminum to produce molten foamed aluminum; and allowing the molten foamed aluminum to cool to below melting temperature. The apparatus for carrying out this invention comprises: a furnace which rotates to simulate the force of gravity and heats the aluminum until it is molten; a door on the furnace, which is opened for charging the aluminum into the furnace, closed for processing and opened again for removal of the foamed aluminum; a gas injection apparatus for injecting gas into the molten aluminum within the furnace; and an extraction apparatus adjacent the door for removing the foamed aluminum from the furnace.

On the imprint of surfactant-driven stabilization of laboratory breaking wave foam with comparison to oceanic whitecaps

NASA Astrophysics Data System (ADS)

Callaghan, A. H.; Deane, G. B.; Stokes, M. D.

2017-08-01

Surfactants are ubiquitous in the global oceans: they help form the materially-distinct sea surface microlayer (SML) across which global ocean-atmosphere exchanges take place, and they reside on the surfaces of bubbles and whitecap foam cells prolonging their lifetime thus altering ocean albedo. Despite their importance, the occurrence, spatial distribution, and composition of surfactants within the upper ocean and the SML remains under-characterized during conditions of vigorous wave breaking when in-situ sampling methods are difficult to implement. Additionally, no quantitative framework exists to evaluate the importance of surfactant activity on ocean whitecap foam coverage estimates. Here we use individual laboratory breaking waves generated in filtered seawater and seawater with added soluble surfactant to identify the imprint of surfactant activity in whitecap foam evolution. The data show a distinct surfactant imprint in the decay phase of foam evolution. The area-time-integral of foam evolution is used to develop a time-varying stabilization function, ϕ>(t>) and a stabilization factor, Θ, which can be used to identify and quantify the extent of this surfactant imprint for individual breaking waves. The approach is then applied to wind-driven oceanic whitecaps, and the laboratory and ocean Θ distributions overlap. It is proposed that whitecap foam evolution may be used to determine the occurrence and extent of oceanic surfactant activity to complement traditional in-situ techniques and extend measurement capabilities to more severe sea states occurring at wind speeds in excess of about 10 m/s. The analysis procedure also provides a framework to assess surfactant-driven variability within and between whitecap coverage data sets.