Sample records for aerogel blanket insulation

  1. Aerogel Blanket Insulation Materials for Cryogenic Applications

    NASA Technical Reports Server (NTRS)

    Coffman, B. E.; Fesmire, J. E.; White, S.; Gould, G.; Augustynowicz, S.

    2009-01-01

    Aerogel blanket materials for use in thermal insulation systems are now commercially available and implemented by industry. Prototype aerogel blanket materials were presented at the Cryogenic Engineering Conference in 1997 and by 2004 had progressed to full commercial production by Aspen Aerogels. Today, this new technology material is providing superior energy efficiencies and enabling new design approaches for more cost effective cryogenic systems. Aerogel processing technology and methods are continuing to improve, offering a tailor-able array of product formulations for many different thermal and environmental requirements. Many different varieties and combinations of aerogel blankets have been characterized using insulation test cryostats at the Cryogenics Test Laboratory of NASA Kennedy Space Center. Detailed thermal conductivity data for a select group of materials are presented for engineering use. Heat transfer evaluations for the entire vacuum pressure range, including ambient conditions, are given. Examples of current cryogenic applications of aerogel blanket insulation are also given. KEYWORDS: Cryogenic tanks, thermal insulation, composite materials, aerogel, thermal conductivity, liquid nitrogen boil-off

  2. Improved Aerogel Vacuum Thermal Insulation

    NASA Technical Reports Server (NTRS)

    Ruemmele, Warren P.; Bue, Grant C.

    2009-01-01

    An improved design concept for aerogel vacuum thermal-insulation panels calls for multiple layers of aerogel sandwiched between layers of aluminized Mylar (or equivalent) poly(ethylene terephthalate), as depicted in the figure. This concept is applicable to both the rigid (brick) form and the flexible (blanket) form of aerogel vacuum thermal-insulation panels. Heretofore, the fabrication of a typical aerogel vacuum insulating panel has involved encapsulation of a single layer of aerogel in poly(ethylene terephthalate) and pumping of gases out of the aerogel-filled volume. A multilayer panel according to the improved design concept is fabricated in basically the same way: Multiple alternating layers of aerogel and aluminized poly(ethylene terephthalate) are assembled, then encapsulated in an outer layer of poly(ethylene terephthalate), and then the volume containing the multilayer structure is evacuated as in the single-layer case. The multilayer concept makes it possible to reduce effective thermal conductivity of a panel below that of a comparable single-layer panel, without adding weight or incurring other performance penalties. Implementation of the multilayer concept is simple and relatively inexpensive, involving only a few additional fabrication steps to assemble the multiple layers prior to evacuation. For a panel of the blanket type, the multilayer concept, affords the additional advantage of reduced stiffness.

  3. Aerogels Insulate Against Extreme Temperatures

    NASA Technical Reports Server (NTRS)

    2010-01-01

    In 1992, NASA started to pursue the development of aerogel for cryogenic insulation. Kennedy Space Center awarded Small Business Innovation Research (SBIR) contracts to Aspen Systems Inc., of Marlborough, Massachusetts, that resulted in a new manufacturing process and a new flexible, durable, easy-to-use form of aerogel. Aspen Systems formed Aspen Aerogels Inc., in Northborough, Massachusetts, to market the product, and by 2009, the company had become the leading provider of aerogel in the United States, producing nearly 20 million square feet per year. With an array of commercial applications, the NASA-derived aerogel has most recently been applied to protect and insulate people s hands and feet.

  4. Analysis and testing of multilayer and aerogel insulation configurations

    SciTech Connect

    Johnson, W L [NASA Kennedy Space Center, Kennedy Space Center, Florida; Demko, Jonathan A [ORNL; Fesmire, J. E. [NASA Kennedy Space Center, Kennedy Space Center, Florida

    2010-01-01

    Multilayer insulation systems that have robust operational characteristics have long been a goal of many research projects. Such thermal insulation systems may need to offer some degree of structural support and/or mechanical integrity during loss of vacuum scenarios while continuing to provide insulative value to the vessel. Aerogel-based composite blankets can be the best insulation materials in ambient pressure environments; in high vacuum, the thermal performance of aerogel improves by about one order of magnitude. Standard multilayer insulation (MLI) is typically 50% worse at ambient pressure and at soft vacuum, but as much as two or three orders of magnitude better at high vacuum. Different combinations of aerogel blanket and multilayer insulation materials have been tested at the Cryogenics Test Laboratory of NASA Kennedy Space Center. Analysis performed at Oak Ridge National Laboratory showed an importance to the relative location of the MLI and aerogel blankets. Apparent thermal conductivity testing under cryogenicvacuum conditions was performed to verify the analytical conclusion. Tests results are shown to be in agreement with the analysis which indicated that the best performance is obtained with aerogel layers located in the middle of the blanket insulation system.

  5. Hybrid Multifoil Aerogel Thermal Insulation

    NASA Technical Reports Server (NTRS)

    Sakamoto, Jeffrey; Paik, Jong-Ah; Jones, Steven; Nesmith, Bill

    2008-01-01

    This innovation blends the merits of multifoil insulation (MFI) with aerogel-based insulation to develop a highly versatile, ultra-low thermally conductive material called hybrid multifoil aerogel thermal insulation (HyMATI). The density of the opacified aerogel is 240 mg/cm3 and has thermal conductivity in the 20 mW/mK range in high vacuum and 25 mW/mK in 1 atmosphere of gas (such as argon) up to 800 C. It is stable up to 1,000 C. This is equal to commercially available high-temperature thermal insulation. The thermal conductivity of the aerogel is 36 percent lower compared to several commercially available insulations when tested in 1 atmosphere of argon gas up to 800 C.

  6. Polyimide-Foam/Aerogel Composites for Thermal Insulation

    NASA Technical Reports Server (NTRS)

    Williams, Martha; Fesmire, James; Sass, Jared; Smith, Trent; Weoser. Erol

    2009-01-01

    Composites of specific types of polymer foams and aerogel particles or blankets have been proposed to obtain thermal insulation performance superior to those of the neat polyimide foams. These composites have potential to also provide enhanced properties for vibration dampening or acoustic attenuation. The specific type of polymer foam is denoted "TEEK-H", signifying a series, denoted H, within a family of polyimide foams that were developed at NASA s Langley Research Center and are collectively denoted TEEK (an acronym of the inventors names). The specific types of aerogels include Nanogel aerogel particles from Cabot Corporation in Billerica, MA. and of Spaceloft aerogel blanket from Aspen Aerogels in Northborough, MA. The composites are inherently flame-retardant and exceptionally thermally stable. There are numerous potential uses for these composites, at temperatures from cryogenic to high temperatures, in diverse applications that include aerospace vehicles, aircraft, ocean vessels, buildings, and industrial process equipment. Some low-temperature applications, for example, include cryogenic storage and transfer or the transport of foods, medicines, and chemicals. Because of thermal cycling, aging, and weathering most polymer foams do not perform well at cryogenic temperatures and will undergo further cracking over time. The TEEK polyimides are among the few exceptions to this pattern, and the proposed composites are intended to have all the desirable properties of TEEK-H foams, plus improved thermal performance along with enhanced vibration or acoustic-attenuation performance. A composite panel as proposed would be fabricated by adding an appropriate amount of TEEK friable balloons into a mold to form a bottom layer. A piece of flexible aerogel blanket material, cut to the desired size and shape, would then be placed on the bottom TEEK layer and sandwiched between another top layer of polyimide friable balloons so that the aerogel blanket would become completely encased in an outer layer of TEEK friable balloons. Optionally, the process could be further repeated to produce multiple aerogel-blanket layers interspersed with and encased by TEEK friable balloons.

  7. Aerogels Insulate Missions and Consumer Products

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Aspen Aerogels, of Northborough, Massachusetts, worked with NASA through an SBIR contract with Kennedy Space Center to develop a robust, flexible form of aerogel for cryogenic insulation for space shuttle launch applications. The company has since used the same manufacturing process developed under the SBIR award to expand its product offerings into the more commercial realms, making the naturally fragile aerogel available for the first time as a standard insulation that can be handled and installed just like standard insulation.

  8. Composite Flexible Blanket Insulation

    NASA Technical Reports Server (NTRS)

    Kourtides, Demetrius A. (inventor); Pitts, William C. (inventor); Goldstein, Howard E. (inventor); Sawko, Paul M. (inventor)

    1991-01-01

    Composite flexible multilayer insulation systems (MLI) were evaluated for thermal performance and compared with the currently used fibrous silica (baseline) insulation system. The systems described are multilayer insulations consisting of alternating layers of metal foil and scrim ceramic cloth or vacuum metallized polymeric films quilted together using ceramic thread. A silicon carbide thread for use in the quilting and the method of making it are also described. These systems are useful in providing lightweight insulation for a variety of uses, particularly on the surface of aerospace vehicles subject to very high temperatures during flight.

  9. Nonflammable, Hydrophobic Aerogel Composites for Insulation

    NASA Technical Reports Server (NTRS)

    Redouane, Begag

    2005-01-01

    Aerogel composites that are both nonflammable and hydrophobic have been developed for use as lightweight thermal- insulation materials for cryogenic systems. Aerogels are well known in the industry for their effectiveness as thermal insulators under cryogenic conditions, but the treatments used heretofore to render them hydrophobic also make them flammable. Nonflammability would make it safer to use aerogel insulation, especially in oxygen-rich environments and on cryogenic systems that contain liquid oxygen. A composite of this type is a silica aerogel reinforced with fibers. In comparison with unreinforced aerogels, the aerogel composite is about ten times as stiff and strong, better able to withstand handling, and more amenable to machining to required shapes. The composite can be made hydrophobic and nonflammable by appropriate design of a sol-gel process used to synthesize the aerogel component. In addition to very low thermal conductivity needed for insulation, aerogel composites of this type have been found to exhibit high resistance to moisture and nonflammability in oxygen-rich atmospheres: Samples floating on water for months gained no weight and showed no signs of deterioration. Samples were found to be nonflammable, even in pure oxygen at atmospheric pressure [14.7 psia (0.10 MPa)

  10. Aerogel

    NSDL National Science Digital Library

    Nanoscale Informal Science Education Network

    2014-06-10

    This activity/demo introduces learners to aerogel, a glass nanofoam. Learners discover how aerogel is made and how well it insulates as well as learn about aerogel's other unique properties. Learners see real aerogel and feel how well it insulates.

  11. Aerogel Beads as Cryogenic Thermal Insulation System

    NASA Technical Reports Server (NTRS)

    Fesmire, J. E.; Augustynowicz, S. D.; Rouanet, S.; Thompson, Karen (Technical Monitor)

    2001-01-01

    An investigation of the use of aerogel beads as thermal insulation for cryogenic applications was conducted at the Cryogenics Test Laboratory of NASA Kennedy Space Center. Steady-state liquid nitrogen boiloff methods were used to characterize the thermal performance of aerogel beads in comparison with conventional insulation products such as perlite powder and multilayer insulation (MLI). Aerogel beads produced by Cabot Corporation have a bulk density below 100 kilograms per cubic meter (kg/cubic m) and a mean particle diameter of 1 millimeter (mm). The apparent thermal conductivity values of the bulk material have been determined under steady-state conditions at boundary temperatures of approximately 293 and 77 kelvin (K) and at various cold vacuum pressures (CVP). Vacuum levels ranged from 10(exp -5) torr to 760 torr. All test articles were made in a cylindrical configuration with a typical insulation thickness of 25 mm. Temperature profiles through the thickness of the test specimens were also measured. The results showed the performance of the aerogel beads was significantly better than the conventional materials in both soft-vacuum (1 to 10 torr) and no-vacuum (760 torr) ranges. Opacified aerogel beads performed better than perlite powder under high-vacuum conditions. Further studies for material optimization and system application are in progress.

  12. Fibrous-Ceramic/Aerogel Composite Insulating Tiles

    NASA Technical Reports Server (NTRS)

    White, Susan M.; Rasky, Daniel J.

    2004-01-01

    Fibrous-ceramic/aerogel composite tiles have been invented to afford combinations of thermal-insulation and mechanical properties superior to those attainable by making tiles of fibrous ceramics alone or aerogels alone. These lightweight tiles can be tailored to a variety of applications that range from insulating cryogenic tanks to protecting spacecraft against re-entry heating. The advantages and disadvantages of fibrous ceramics and aerogels can be summarized as follows: Tiles made of ceramic fibers are known for mechanical strength, toughness, and machinability. Fibrous ceramic tiles are highly effective as thermal insulators in a vacuum. However, undesirably, the porosity of these materials makes them permeable by gases, so that in the presence of air or other gases, convection and gas-phase conduction contribute to the effective thermal conductivity of the tiles. Other disadvantages of the porosity and permeability of fibrous ceramic tiles arise because gases (e.g., water vapor or cryogenic gases) can condense in pores. This condensation contributes to weight, and in the case of cryogenic systems, the heat of condensation undesirably adds to the heat flowing to the objects that one seeks to keep cold. Moreover, there is a risk of explosion associated with vaporization of previously condensed gas upon reheating. Aerogels offer low permeability, low density, and low thermal conductivity, but are mechanically fragile. The basic idea of the present invention is to exploit the best features of fibrous ceramic tiles and aerogels. In a composite tile according to the invention, the fibrous ceramic serves as a matrix that mechanically supports the aerogel, while the aerogel serves as a low-conductivity, low-permeability filling that closes what would otherwise be the open pores of the fibrous ceramic. Because the aerogel eliminates or at least suppresses permeation by gas, gas-phase conduction, and convection, the thermal conductivity of such a composite even at normal atmospheric pressure is not much greater than that of the fibrous ceramic alone in a vacuum.

  13. Aerogel Insulation Systems for Space Launch Applications

    NASA Technical Reports Server (NTRS)

    Fesmire, James E.

    2005-01-01

    New developments in materials science in the areas of solution gelation processes and nanotechnology have led to the recent commercial production of aerogels. Concurrent with these advancements has been the development of new approaches to cryogenic thermal insulation systems. For example, thermal and physical characterizations of aerogel beads under cryogenic-vacuum conditions have been performed at the Cryogenics Test Laboratory of the NASA Kennedy Space Center. Aerogel-based insulation system demonstrations have also been conducted to improve performance for space launch applications. Subscale cryopumping experiments show the thermal insulating ability of these fully breathable nanoporous materials. For a properly executed thermal insulation system, these breathable aerogel systems are shown to not cryopump beyond the initial cooldown and thermal stabilization phase. New applications are being developed to augment the thermal protection systems of space launch vehicles, including the Space Shuttle External Tank. These applications include a cold-boundary temperature of 90 K with an ambient air environment in which both weather and flight aerodynamics are important considerations. Another application is a nitrogen-purged environment with a cold-boundary temperature of 20 K where both initial cooldown and launch ascent profiles must be considered. Experimental results and considerations for these flight system applications are discussed.

  14. Method of fabricating a multilayer insulation blanket

    DOEpatents

    Gonczy, John D. (Oak Lawn, IL); Niemann, Ralph C. (Downers Grove, IL); Boroski, William N. (Aurora, IL)

    1993-01-01

    An improved multilayer insulation blanket for insulating cryogenic structures operating at very low temperatures is disclosed. An apparatus and method for fabricating the improved blanket are also disclosed. In the improved blanket, each successive layer of insulating material is greater in length and width than the preceding layer so as to accommodate thermal contraction of the layers closest to the cryogenic structure. The fabricating apparatus has a rotatable cylindrical mandrel having an outer surface of fixed radius that is substantially arcuate, preferably convex, in cross-section. The method of fabricating the improved blanket comprises (a) winding a continuous sheet of thermally reflective material around the circumference of the mandrel to form multiple layers, (b) binding the layers along two lines substantially parallel to the edges of the circumference of the mandrel, (c) cutting the layers along a line parallel to the axle of the mandrel, and (d) removing the bound layers from the mandrel.

  15. Multilayer insulation blanket, fabricating apparatus and method

    DOEpatents

    Gonczy, John D. (Oak Lawn, IL); Niemann, Ralph C. (Downers Grove, IL); Boroski, William N. (Aurora, IL)

    1992-01-01

    An improved multilayer insulation blanket for insulating cryogenic structures operating at very low temperatures is disclosed. An apparatus and method for fabricating the improved blanket are also disclosed. In the improved blanket, each successive layer of insulating material is greater in length and width than the preceding layer so as to accommodate thermal contraction of the layers closest to the cryogenic structure. The fabricating apparatus has a rotatable cylindrical mandrel having an outer surface of fixed radius that is substantially arcuate, preferably convex, in cross-section. The method of fabricating the improved blanket comprises (a) winding a continuous sheet of thermally reflective material around the circumference of the mandrel to form multiple layers, (b) binding the layers along two lines substantially parallel to the edges of the circumference of the mandrel, (c) cutting the layers along a line parallel to the axle of the mandrel, and (d) removing the bound layers from the mandrel.

  16. Method of fabricating a multilayer insulation blanket

    DOEpatents

    Gonczy, J.D.; Niemann, R.C.; Boroski, W.N.

    1993-07-06

    An improved multilayer insulation blanket for insulating cryogenic structures operating at very low temperatures is disclosed. An apparatus and method for fabricating the improved blanket are also disclosed. In the improved blanket, each successive layer of insulating material is greater in length and width than the preceding layer so as to accommodate thermal contraction of the layers closest to the cryogenic structure. The fabricating apparatus has a rotatable cylindrical mandrel having an outer surface of fixed radius that is substantially arcuate, preferably convex, in cross-section. The method of fabricating the improved blanket comprises (a) winding a continuous sheet of thermally reflective material around the circumference of the mandrel to form multiple layers, (b) binding the layers along two lines substantially parallel to the edges of the circumference of the mandrel, (c) cutting the layers along a line parallel to the axle of the mandrel, and (d) removing the bound layers from the mandrel.

  17. Multilayer insulation blanket, fabricating apparatus and method

    DOEpatents

    Gonczy, J.D.; Niemann, R.C.; Boroski, W.N.

    1992-09-01

    An improved multilayer insulation blanket for insulating cryogenic structures operating at very low temperatures is disclosed. An apparatus and method for fabricating the improved blanket are also disclosed. In the improved blanket, each successive layer of insulating material is greater in length and width than the preceding layer so as to accommodate thermal contraction of the layers closest to the cryogenic structure. The fabricating apparatus has a rotatable cylindrical mandrel having an outer surface of fixed radius that is substantially arcuate, preferably convex, in cross-section. The method of fabricating the improved blanket comprises (a) winding a continuous sheet of thermally reflective material around the circumference of the mandrel to form multiple layers, (b) binding the layers along two lines substantially parallel to the edges of the circumference of the mandrel, (c) cutting the layers along a line parallel to the axle of the mandrel, and (d) removing the bound layers from the mandrel. 7 figs.

  18. Novel Cryogenic Insulation Materials: Aerogel Composites

    NASA Technical Reports Server (NTRS)

    White, Susan

    2001-01-01

    New insulation materials are being developed to economically and reliably insulate future reusable spacecraft cryogenic tanks over a planned lifecycle of extreme thermal challenges. These insulation materials must prevent heat loss as well as moisture and oxygen condensation on the cryogenic tanks during extended groundhold, must withstand spacecraft launch conditions, and must protect a partly full or empty reusable cryogenic tank from significant reentry heating. To perform over such an extreme temperature range, novel composites were developed from aerogels and high-temperature matrix material such as Space Shuttle tile. These materials were fabricated and tested for use both as cryogenic insulation and as high-temperature insulation. The test results given in this paper were generated during spacecraft re-entry heating simulation tests using cryogenic cooling.

  19. Aerogel insulation applications for liquid hydrogen launch vehicle tanks

    Microsoft Academic Search

    J. E. Fesmire; J. P. Sass

    2008-01-01

    Solutions to thermal insulation problems using aerogel beads were demonstrated for space launch vehicles using a model of the space shuttle external tank’s liquid hydrogen (LH2) intertank. Test results using liquid helium show that with aerogel, the nitrogen mass inside the intertank is greatly reduced and free liquid nitrogen is eliminated. Physisorption within the aerogel was also investigated, showing that

  20. Aerogel Insulation Applications for Liquid Hydrogen Launch Vehicle Tanks

    NASA Technical Reports Server (NTRS)

    Fesmire, J. E.; Sass, J.

    2007-01-01

    Aerogel based insulation systems for ambient pressure environments were developed for liquid hydrogen (LH2) tank applications. Solutions to thermal insulation problems were demonstrated for the Space Shuttle External Tank (ET) through extensive testing at the Cryogenics Test Laboratory. Demonstration testing was performed using a 1/10th scale ET LH2 intertank unit and liquid helium as the coolant to provide the 20 K cold boundary temperature. Cryopumping tests in the range of 20K were performed using both constant mass and constant pressure methods. Long-duration tests (up to 10 hours) showed that the nitrogen mass taken up inside the intertank is reduced by a factor of nearly three for the aerogel insulated case as compared to the un-insulated (bare metal flight configuration) case. Test results including thermal stabilization, heat transfer effectiveness, and cryopumping confirm that the aerogel system eliminates free liquid nitrogen within the intertank. Physisorption (or adsorption) of liquid nitrogen within the fine pore structure of aerogel materials was also investigated. Results of a mass uptake method show that the sorption ratio (liquid nitrogen to aerogel beads) is about 62 percent by volume. A novel liquid nitrogen production method of testing the liquid nitrogen physical adsorption capacity of aerogel beads was also performed to more closely approximate the actual launch vehicle cooldown and thermal stabilization effects within the aerogel material. The extraordinary insulating effectiveness of the aerogel material shows that cryopumping is not an open-cell mass transport issue but is strictly driven by thermal communication between warm and cold surfaces. The new aerogel insulation technology is useful to solve heat transfer problem areas and to augment existing thermal protection systems on launch vehicles. Examples are given and potential benefits for producing launch systems that are more reliable, robust, reusable, and efficient are outlined.

  1. Aerogel-Based Multilayer Insulation with Micrometeoroid Protection

    NASA Technical Reports Server (NTRS)

    Begag, Redouane; White, Shannon

    2013-01-01

    Ultra-low-density, highly hydrophobic, fiber-reinforced aerogel material integrated with MLI (aluminized Mylar reflectors and B4A Dacron separators) offers a highly effective insulation package by providing unsurpassed thermal performance and significant robustness, delivering substantial MMOD protection via the addition of a novel, durable, external aerogel layer. The hydrophobic nature of the aerogel is an important property for maintaining thermal performance if the material is exposed to the environment (i.e. rain, snow, etc.) during ground installations. The hybrid aerogel/MLI/MMOD solution affords an attractive alternative because it will perform thermally in the same range as MLI at all vacuum levels (including high vacuum), and offers significant protection from micrometeoroid damage. During this effort, the required low-density and resilient aerogel materials have been developed that are needed to optimize the thermal performance for space (high vacuum) cryotank applications. The proposed insulation/MMOD package is composed of two sections: a stack of interleaved aerogel layers and MLI intended for cryotank thermal insulation, and a 1.5- to 1-in. (.2.5- to 3.8- cm) thick aerogel layer (on top of the insulation portion) for MMOD protection. Learning that low-density aerogel cannot withstand the hypervelocity impact test conditions, the innovators decided during the course of the program to fabricate a high-density and strong material based on a cross-linked aerogel (X-aerogel; developed elsewhere by the innovators) for MMOD protection. This system has shown a very high compressive strength that is capable of withstanding high-impact tests if a proper configuration of the MMOD aerogel layer is used. It was learned that by stacking two X-aerogel layers [1.5-in. (.3.8-cm) thick] separated by an air gap, the system would be able to hold the threat at a speed of 5 km/s and gpass h the test. The first aerogel panel stopped the projectile from damaging the second aerogel panel. The impacted X-aerogel (the back specimen from the successful test) was further tested in comparison to another similar sample (not impacted) at Kennedy Space Center for thermal conductivity evaluation at cryogenic conditions. The specimens were tested under high vacuum and cryogenic temperatures, using Cryostat 500. The results show that the specimen did not lose a significant amount of thermal performance due to the impact test, especially at high vacuum.

  2. Thin Thermal-Insulation Blankets for Very High Temperatures

    NASA Technical Reports Server (NTRS)

    Choi, Michael K.

    2003-01-01

    Thermal-insulation blankets of a proposed type would be exceptionally thin and would endure temperatures up to 2,100 C. These blankets were originally intended to protect components of the NASA Solar Probe spacecraft against radiant heating at its planned closest approach to the Sun (a distance of 4 solar radii). These blankets could also be used on Earth to provide thermal protection in special applications (especially in vacuum chambers) for which conventional thermal-insulation blankets would be too thick or would not perform adequately.

  3. Development of windows based on highly insulating aerogel glazings

    Microsoft Academic Search

    K. I. Jensen; J. M. Schultz; F. H. Kristiansen

    2004-01-01

    Within a finished and a current EU project, research and development are being carried out on the use of monolithic silica aerogel as transparent insulation in windows. Results related to the window application will be presented here. At the thermal envelope of buildings, the window area is the weakest part with respect to heat loss, but at the same time,

  4. Process for forming transparent aerogel insulating arrays

    DOEpatents

    Tewari, P.H.; Hunt, A.J.

    1985-09-04

    An improved supercritical drying process for forming transparent silica aerogel arrays is described. The process is of the type utilizing the steps of hydrolyzing and condensing aloxides to form alcogels. A subsequent step removes the alcohol to form aerogels. The improvement includes the additional step, after alcogels are formed, of substituting a solvent, such as CO/sub 2/, for the alcohol in the alcogels, the solvent having a critical temperature less than the critical temperature of the alcohol. The resulting gels are dried at a supercritical temperature for the selected solvent, such as CO/sub 2/, to thereby provide a transparent aerogel array within a substantially reduced (days-to-hours) time period. The supercritical drying occurs at about 40/sup 0/C instead of at about 270/sup 0/C. The improved process provides increased yields of large scale, structurally sound arrays. The transparent aerogel array, formed in sheets or slabs, as made in accordance with the improved process, can replace the air gap within a double glazed window, for example, to provide a substantial reduction in heat transfer. The thus formed transparent aerogel arrays may also be utilized, for example, in windows of refrigerators and ovens, or in the walls and doors thereof or as the active material in detectors for analyzing high energy elementary particles or cosmic rays.

  5. Process for forming transparent aerogel insulating arrays

    DOEpatents

    Tewari, Param H. (Milpitas, CA); Hunt, Arlon J. (Oakland, CA)

    1986-01-01

    An improved supercritical drying process for forming transparent silica aerogel arrays is described. The process is of the type utilizing the steps of hydrolyzing and condensing aloxides to form alcogels. A subsequent step removes the alcohol to form aerogels. The improvement includes the additional step, after alcogels are formed, of substituting a solvent, such as CO.sub.2, for the alcohol in the alcogels, the solvent having a critical temperature less than the critical temperature of the alcohol. The resulting gels are dried at a supercritical temperature for the selected solvent, such as CO.sub.2, to thereby provide a transparent aerogel array within a substantially reduced (days-to-hours) time period. The supercritical drying occurs at about 40.degree. C. instead of at about 270.degree. C. The improved process provides increased yields of large scale, structurally sound arrays. The transparent aerogel array, formed in sheets or slabs, as made in accordance with the improved process, can replace the air gap within a double glazed window, for example, to provide a substantial reduction in heat transfer. The thus formed transparent aerogel arrays may also be utilized, for example, in windows of refrigerators and ovens, or in the walls and doors thereof or as the active material in detectors for analyzing high energy elementry particles or cosmic rays.

  6. Low-Density, Aerogel-Filled Thermal-Insulation Tiles

    NASA Technical Reports Server (NTRS)

    Santos, Maryann; Heng, Vann; Barney, Andrea; Oka, Kris; Droege, Michael

    2005-01-01

    Aerogel fillings have been investigated in a continuing effort to develop low-density thermal-insulation tiles that, relative to prior such tiles, have greater dimensional stability (especially less shrinkage), equal or lower thermal conductivity, and greater strength and durability. In preparation for laboratory tests of dimensional and thermal stability, prototypes of aerogel-filled versions of recently developed low-density tiles have been fabricated by impregnating such tiles to various depths with aerogel formations ranging in density from 1.5 to 5.6 lb/ft3 (about 53 to 200 kg/cu m). Results available at the time of reporting the information for this article showed that the thermal-insulation properties of the partially or fully aerogel- impregnated tiles were equivalent or superior to those of the corresponding non-impregnated tiles and that the partially impregnated tiles exhibited minimal (<1.5 percent) shrinkage after multiple exposures at a temperature of 2,300 F (1,260 C). Latest developments have shown that tiles containing aerogels at the higher end of the density range are stable after multiple exposures at the said temperature.

  7. Sprayable Aerogel Bead Compositions With High Shear Flow Resistance and High Thermal Insulation Value

    NASA Technical Reports Server (NTRS)

    Ou, Danny; Trifu, Roxana; Caggiano, Gregory

    2013-01-01

    A sprayable aerogel insulation has been developed that has good mechanical integrity and lower thermal conductivity than incumbent polyurethane spray-on foam insulation, at similar or lower areal densities, to prevent insulation cracking and debonding in an effort to eliminate the generation of inflight debris. This new, lightweight aerogel under bead form can be used as insulation in various thermal management systems that require low mass and volume, such as cryogenic storage tanks, pipelines, space platforms, and launch vehicles.

  8. Aerogel: From Aerospace to Apparel

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Aspen Systems Inc. developed an aerogel-manufacturing process solved the handling problems associated with aerogel-based insulation products. Their aerogels can now be manufactured into blankets, thin sheets, beads, and molded parts; and may be transparent, translucent, or opaque. Aspen made the material effective for window and skylight insulation, non-flammable building insulation, and inexpensive firewall insulation that will withstand fires in homes and buildings, and also assist in the prevention of forest fires. Another Aspen product is Spaceloft(TM); an inexpensive, flexible blanket that incorporates a thin layer of aerogel embedded directly into the fabric. Spaceloft, is incorporated into jackets intended for wear in extremely harsh conditions and activities, such as Antarctic expeditions.

  9. Tailorable advanced blanket insulation using aluminoborosilicate and alumina batting

    NASA Technical Reports Server (NTRS)

    Calamito, Dominic P.

    1989-01-01

    Two types of Tailorable Advanced Blanket Insulation (TABI) flat panels for Advanced Space Transportation Systems were produced. Both types consisted of integrally woven, 3-D fluted core having parallel faces and connecting ribs of Nicalon yarns. The triangular cross section flutes of one type was filled with mandrels of processed Ultrafiber (aluminoborosilicate) stitchbonded Nextel 440 fibrous felt, and the second type wall filled with Saffil alumina fibrous felt insulation. Weaving problems were minimal. Insertion of the fragile insulation mandrels into the fabric flutes was improved by using a special insertion tool. An attempt was made to weave fluted core fabrics from Nextel 440 yarns but was unsuccessful because of the yarn's fragility. A small sample was eventually produced by an unorthodox weaving process and then filled with Saffil insulation. The procedures for setting up and weaving the fabrics and preparing and inserting insulation mandrels are discussed. Characterizations of the panels produced are also presented.

  10. Thermal Performance Of Space Suit Elements With Aerogel Insulation For Moon And Mars Exploration

    NASA Technical Reports Server (NTRS)

    Tang, Henry H.; Orndoff, Evelyne S.; Trevino, Luis A.

    2006-01-01

    Flexible fiber-reinforced aerogel composites were studied for use as insulation materials of a future space suit for Moon and Mars exploration. High flexibility and good thermal insulation properties of fiber-reinforced silica aerogel composites at both high and low vacuum conditions make it a promising insulation candidate for the space suit application. This paper first presents the results of a durability (mechanical cycling) study of these aerogels composites in the context of retaining their thermal performance. The study shows that some of these Aerogels materials retained most of their insulation performance after up to 250,000 cycles of mechanical flex cycling. This paper also examines the problem of integrating these flexible aerogel composites into the current space suit elements. Thermal conductivity evaluations are proposed for different types of aerogels space suit elements to identify the lay-up concept that may have the best overall thermal performance for both Moon and Mars environments. Potential solutions in mitigating the silica dusting issue related to the application of these aerogels materials for the space suit elements are also discussed.

  11. Heat insulation performance, mechanics and hydrophobic modification of cellulose-SiO2 composite aerogels.

    PubMed

    Shi, Jianjun; Lu, Lingbin; Guo, Wantao; Zhang, Jingying; Cao, Yang

    2013-10-15

    Cellulose-SiO2 composite hydrogel was prepared by combining the NaOH/thiourea/H2O solvent system and the immersion method with controlling the hydrolysis-fasculation rate of tetraethyl orthosilicate (TEOS). The hydrophobic composite aerogels were obtained through the freeze-drying technology and the cold plasma modification technology. Composite SiO2 could obviously reduce the thermal conductivity of cellulose aerogel. The thermal conductivity could be as low as 0.026 W/(mK). The thermal insulation mechanism of the aerogel material was discussed. Composite SiO2 reduced hydrophilicity of cellulose aerogel, but environmental humidity had a significant influence on heat insulation performance. After hydrophobic modification using CCl4 as plasma was conducted, the surface of composite aerogel was changed from hydrophilic to hydrophobic and water contact angle was as high as 132°. The modified composite aerogel still kept good heat insulation performance. This work provided a foundation for the possibility of applying cellulose-SiO2 composite aerogel in the insulating material field. PMID:23987346

  12. Sorption Properties of Aerogel in Liquid Nitrogen

    NASA Technical Reports Server (NTRS)

    Johnson, Wesley L.

    2006-01-01

    Aerogel products are now available as insulation materials of the future. The Cryogenics Test Laboratory at the NASA Kennedy Space Center is developing aerogel-based thermal insulation systems for space launch applications. Aerogel beads (Cabot Nanogel ) and aerogel blankets (Aspen Aerogels Spaceloft ) have outstanding ambient pressure thermal performance that makes them useful for applications where sealing is not possible. Aerogel beads are open-celled silicone dioxide and have tiny pores that run throughout the body of the bead. It has also recently been discovered that aerogel beads can be used as a filtering device for aqueous compounds at room temperature. With their hydrophobic covering, the beads absorb any non-polar substance and they can be chemically altered to absorb hot gases. The combination of the absorption and cryogenic insulating properties of aerogel beads have never been studied together. For future cryogenic insulation applications, it is crucial to know how the beads react while immersed in cryogenic liquids, most notably liquid nitrogen. Aerogel beads in loose-fill situation and aerogel blankets with composite fiber structure have been tested for absorption properties. Depending on the type of aerogel used and the preparation, preliminary results show the material can absorb up to seven times its own weight of liquid nitrogen, corresponding to a volumetric ratio of 0.70 (unit volume nitrogen per unit volume aerogel). These tests allow for an estimate on how much insulation is needed in certain situations. The theory behind the different processes of sorption is necessary for a better understanding of the preparation of the beads before they are used in an insulation system.

  13. 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.

  14. Advanced thermal insulation for energy efficient buildings : structural performance of aerogel composite panels

    E-print Network

    Goutierre, Thomas

    2011-01-01

    Aerogels are well known as exceptional thermal insulators. Thermal conductivities of 9 to 10 mW/m.K have been achieved at atmospheric pressure, and a moderate vacuum (between 1/3 and 1/10 of an atmosphere) can lower this ...

  15. Effects of weave architecture on aeroacoustic performance of ceramic insulation blankets

    Microsoft Academic Search

    P. M. Sawko; D. Tran

    1993-01-01

    A comparison of sewn, quilted Advanced Flexible Reusable Surface Insulation (AFRSI) blankets and integrally woven core Tailorable Advanced Blanket Insulation (TABI) systems was conducted in a 170 decibel aeroacoustic environment under oscillating air loads. Preconditioning in a radiant heat source was done at both 2,000[degrees]F and 2,500[degrees]F before testing. It was shown that a multilayer weave construction based on an

  16. Silicon Oxycarbide Aerogels for High-Temperature Thermal Insulation

    NASA Technical Reports Server (NTRS)

    Evans, Owen; Rhine, Wendell; Coutinho, Decio

    2010-01-01

    This work has shown that the use of SOC-A35 leads to aerogel materials containing a significant concentration of carbidic species and limited amorphous free carbon. Substitution of the divalent oxide species in silica with tetravalent carbidic carbon has directly led to materials that exhibit increased network viscosity, reduced sintering, and limited densification. The SiOC aerogels produced in this work have the highest carbide content of any dense or porous SiOC glass reported in the literature at that time, and exhibit tremendous long-term thermal stability.

  17. Polyurea-Based Aerogel Monoliths and Composites

    NASA Technical Reports Server (NTRS)

    Lee, Je Kyun

    2012-01-01

    aerogel insulation material was developed that will provide superior thermal insulation and inherent radiation protection for government and commercial applications. The rubbery polyureabased aerogel exhibits little dustiness, good flexibility and toughness, and durability typical of the parent polyurea polymer, yet with the low density and superior insulation properties associated with aerogels. The thermal conductivity values of polyurea-based aerogels at lower temperature under vacuum pressures are very low and better than that of silica aerogels. Flexible, rubbery polyurea-based aerogels are able to overcome the weak and brittle nature of conventional inorganic and organic aerogels, including polyisocyanurate aerogels, which are generally prepared with the one similar component to polyurethane rubber aerogels. Additionally, with higher content of hydrogen in their structures, the polyurea rubber-based aerogels will also provide inherently better radiation protection than those of inorganic and carbon aerogels. The aerogel materials also demonstrate good hydrophobicity due to their hydrocarbon molecular structure. There are several strategies to overcoming the drawbacks associated with the weakness and brittleness of silica aerogels. Development of the flexible fiber-reinforced silica aerogel composite blanket has proven to be one promising approach, providing a conveniently fielded form factor that is relatively robust in industrial environments compared to silica aerogel monoliths. However, the flexible, silica aerogel composites still have a brittle, dusty character that may be undesirable, or even intolerable, in certain application environments. Although the cross - linked organic aerogels, such as resorcinol- formaldehyde (RF), polyisocyanurate, and cellulose aerogels, show very high impact strength, they are also very brittle with little elongation (i.e., less rubbery). Also, silica and carbon aerogels are less efficient radiation shielding materials due to their lower content of hydrogen element. The invention involves mixing at least one isocyanate resin in solvent along with a specific amount of at least one polyamine hardener. The hardener is selected from a group of polyoxyalkyleneamines, amine-based polyols, or a mixture thereof. Mixing is performed in the presence of a catalyst and reinforcing inorganic and/or organic materials, and the system is then subjected to gelation, aging, and supercritical drying. The aerogels will offer exceptional flexibility, excellent thermal and physical properties, and good hydrophobicity. The rubbery polyurea-based aerogels are very flexible with no dust and hydrophobic organics that demonstrated the following ranges of typical properties: densities of 0.08 to 0.293 g/cu cm, shrinkage factor (raerogel/rtarget) = 1.6 to 2.84, and thermal conductivity values of 15.2 to 20.3 mW/m K.

  18. Composite,Cryogenic, Conformal, Common Bulkhead, Aerogel-Insulated Tank (CBAT)

    NASA Technical Reports Server (NTRS)

    Roberts, J. K.; Kovach, M. P.; McMahon, W. M.; Finckenor, J. L.

    2001-01-01

    The objective of the Composite, Cryogenic, Conformal, Common Bulkhead, Aerogel-insulated Tank (CBAT) Program is to evaluate the potential for using various new technologies in next generation Reusable Launch Vehicles (RLVs) through design, fabrication, and testing of a subscale system. The new technologies include polymer matrix composites (PMCs), conformal propellant storage, common bulkhead packaging, and aerogel insulation. The National Aeronautics and Space Administration (NASA) and Thiokol Propulsion from Cordant Technologies are working together to develop a design and the processing methodologies which will allow integration of these technologies into a single structural component assembly. Such integration will significantly decrease subsystem weight and reduce shape, volume, and placement restrictions, thereby enhancing overall launch system performance. This paper/presentation focuses on the challenges related to materials and processes that were encountered and overcome during this program to date.

  19. The efficiency of night insulation using aerogel-filled polycarbonate panels during the heating season

    NASA Astrophysics Data System (ADS)

    Adelsberger, Kathleen

    Energy is the basis for modern life. All modern technology from a simple coffee maker to massive industrial facilities is powered by energy. While the demand for energy is increasing, our planet is suffering from the consequences of using fossil fuels to generate electricity. Therefore, the world is looking at clean energy and solar power to minimize this effect on our environment. However, saving energy is extremely important even for clean energy. The more we save the less we have to generate. Heat retention in buildings is one step towards achieving passive heating. Therefore, efforts are made to prevent heat from escaping buildings through the glass during cold nights. Movable insulation is a way to increase the insulation value of the glass to reduce heat loss towards the outdoor. This thesis examines the performance of the aerogel-filled polycarbonate movable panels in the Ecohawks building, a building located on the west campus of The University of Kansas. Onsite tests were performed using air and surface temperature sensors to determine the effectiveness of the system. Computer simulations were run by Therm 7.2 simulation software to explore alternative design options. A cost analysis was also performed to evaluate the feasibility of utilizing movable insulation to reduce the heating bills during winter. Results showed that sealed movable insulation reduces heat loss through the glazing by 67.5%. Replacing aerogel with XPS panels reduces this percentage to 64.3%. However, it reduces the cost of the insulation material by 98%.

  20. Thermo-hygric properties of a newly developed aerogel based insulation rendering for both exterior and interior applications

    Microsoft Academic Search

    Th. Stahl; S. Brunner; M. Zimmermann; K. Ghazi Wakili

    A new kind of rendering based on silica aerogel granulates was developed showing a high performance namely a low thermal conductivity and a low vapour transmission resistance, a combination of characteristics unachieved by existing renderings. This insulation rendering has a clear advantage over insulation boards which need a plane subsurface, adjustment, gluing and even fastening by means of dowels. A

  1. Electrically insulating coatings for V-Li self-cooled blanket in a fusion system

    SciTech Connect

    Natesan, K.; Reed, C. B.; Uz, M.; Park, J. H.; Smith, D. L.

    2000-05-17

    The blanket system is one of the most important components in a fusion reactor because it has a major impact on both the economics and safety of fusion energy. The primary functions of the blanket in a deuterium/tritium-fueled fusion reactor are to convert the fusion energy into sensible heat and to breed tritium for the fuel cycle. The liquid-metal blanket concept requires an electrically insulating coating on the first-wall structural material to minimize the magnetohydrodynamic pressure drop that occurs during the flow of liquid metal in a magnetic field. Based on the thermodynamics of interactions between the coating and the liquid lithium on one side and the structural V-base alloy on the other side, several coating candidates are being examined to perform the insulating function over a wide range of temperatures and lithium chemistries.

  2. A Thermal Resistance (R-Value) Correlation for Blow-in-Blanket Mineral Fiber Insulation

    Microsoft Academic Search

    David W. Yarbrough; Clay C. Bare

    1992-01-01

    A correlation between the apparent thermal conductivity, measured at 75°F, and density of mineral fiber insulation has been developed for the fiber most commonly used in Blow-in-Blanket (BIB) applications. The correlation describes the data obtained for specimens prepared by six contractors to within ±5% in the den sity range 1.6 to 3.0 1b\\/ft3. R-value per inch increased from 3.85 ft2.hr.°F\\/Btu.in

  3. Thermal blanket insulation for advanced space transportation systems

    NASA Technical Reports Server (NTRS)

    Pusch, Richard H.

    1985-01-01

    The feasibility of weaving Nextel ceramic and Nicalon silicon carbide yarns into integrally woven, three dimensional fluted core fabrics was demonstrated. Parallel face fabrics joined with woven fabric ribs to form triangular cross section flutes between the faces were woven into three single and one double layer configuration. High warp yarn density in the double layer configuration caused considerable yarn breakage during weaving. The flutes of all four fabrics were filled with mandrels made from Q-Fiber Felt and FRCI-20-12 to form candidate insulation panels for advanced Space Transportation Systems. Procedures for preparing and inserting the mandrels were developed. Recommendations are made on investigating alternate methods for filling the flutes with insulation, and for improving the weaving of these types of fabrics.

  4. Development of tailorable advanced blanket insulation for advanced space transportation systems

    NASA Technical Reports Server (NTRS)

    Calamito, Dominic P.

    1987-01-01

    Two items of Tailorable Advanced Blanket Insulation (TABI) for Advanced Space Transportation Systems were produced. The first consisted of flat panels made from integrally woven, 3-D fluted core having parallel fabric faces and connecting ribs of Nicalon silicon carbide yarns. The triangular cross section of the flutes were filled with mandrels of processed Q-Fiber Felt. Forty panels were prepared with only minimal problems, mostly resulting from the unavailability of insulation with the proper density. Rigidizing the fluted fabric prior to inserting the insulation reduced the production time. The procedures for producing the fabric, insulation mandrels, and TABI panels are described. The second item was an effort to determine the feasibility of producing contoured TABI shapes from gores cut from flat, insulated fluted core panels. Two gores of integrally woven fluted core and single ply fabric (ICAS) were insulated and joined into a large spherical shape employing a tadpole insulator at the mating edges. The fluted core segment of each ICAS consisted of an Astroquartz face fabric and Nicalon face and rib fabrics, while the single ply fabric segment was Nicalon. Further development will be required. The success of fabricating this assembly indicates that this concept may be feasible for certain types of space insulation requirements. The procedures developed for weaving the ICAS, joining the gores, and coating certain areas of the fabrics are presented.

  5. Development of a new multi-layer insulation blanket with non-interlayer-contact spacer for space cryogenic mission

    NASA Astrophysics Data System (ADS)

    Miyakita, Takeshi; Hatakenaka, Ryuta; Sugita, Hiroyuki; Saitoh, Masanori; Hirai, Tomoyuki

    2014-11-01

    For conventional Multi-Layer Insulation (MLI) blankets, it is difficult to control the layer density and the thermal insulation performance degrades due to the increase in conductive heat leak through interlayer contacts. At low temperatures, the proportion of conductive heat transfer through MLI blankets is large compared to that of radiative heat transfer, hence the decline in thermal insulation performance is significant. A new type of MLI blanket using new spacers; the Non-Interlayer-Contact Spacer MLI (NICS MLI) has been developed. This new MLI blanket uses small discrete spacers and can exclude uncertain interlayer contact between films. It is made of polyetheretherketone (PEEK) making it suitable for space use. The cross-sectional area to length ratio of the spacer is 1.0 × 10-5 m with a 10 mm diameter and 4 mm height. The insulation performance is measured with a boil-off calorimeter. Because the NICS MLI blanket can exclude uncertain interlayer contact, the test results showed good agreement with estimations. Furthermore, the NICS MLI blanket shows significantly good insulation performance (effective emissivity is 0.0046 at ordinary temperature), particularly at low temperatures, due to the high thermal resistance of this spacer.

  6. Hybrid aerogel rigid ceramic fiber insulation and method of producing same

    NASA Technical Reports Server (NTRS)

    Barney, Andrea O. (Inventor); Heng, Vann (Inventor); Oka, Kris Shigeko (Inventor); Santos, Maryann (Inventor); Zinn, Alfred A. (Inventor); Droege, Michael (Inventor)

    2004-01-01

    A hybrid insulation material comprises of porous ceramic substrate material impregnated with nanoporous material and method of making the same is the topic of this invention. The porous substrate material has bulk density ranging from 6 to 20 lb/ft.sup.3 and is composed of about 60 to 80 wt % silica (SiO.sub.2) 20 to 40 wt % alumina (Al.sub.2 O.sub.3) fibers, and with about 0.1 to 1.0 wt % boron-containing constituent as the sintering agent. The nanoporous material has density ranging from 1.0 to 10 lb/ft.sup.3 and is either fully or partially impregnated into the substrate to block the pores, resulting in substantial reduction in conduction via radiation and convention. The nanoporous material used to impregnate the fiber substrate is preferably formed from a precursor of alkoxysilane, alcohol, water, and an acid or base catalyst for silica aerogels, and from a precursor of aluminum alkoxide, alcohol, water, and an acid or base catalyst for alumina aerogels.

  7. Development of electrically insulating coatings on vanadium alloys for lithium-cooled blankets

    SciTech Connect

    Smith, D.L.; Natesan, K.; Park, J.H.; Mattas, R.; Reed, C.

    1997-10-01

    The self-cooled lithium blanket concept with a vanadium structure offers a potential for high performance with attractive safety and environmental features. Based on blanket design studies, it became apparent that electrically insulating duct walls would be required to reduce the magnetohydrodynamic (MHD) pressure drop for liquid metal-cooled blankets for high magnetic field fusion devices. As a result, development of insulator coatings was recommended as the most appropriate approach for resolving this issue. Oxides such as CaO, Y{sub 2}O{sub 3}, BeO, MgO, MgAl{sub 2}O{sub 4}, and Y{sub 3}Al{sub 2}O{sub 12} and nitrides such as AlN, BN and Si{sub 3}N{sub 2} were initially considered potential candidate coating materials. Based on results of scoping studies, CaO and AlN have been selected as primary candidates for further development. Progress on the development of CaO and AlN coatings, including in-situ formation and electrical properties measurements, are summarized in this paper.

  8. The development of a direct insulation layer for the liquid metal cooled fusion reactor blanket

    SciTech Connect

    Borgstedt, H.U.; Glasbrenner, H. [Institut fuer Materialforschung III, Karlsruhe (Germany)

    1994-12-31

    The suppression of MHD pressure drops in the channels, in which liquid metal is flowing in a strong magnetic field, is necessary to get a sufficient cooling effect in the self-cooled liquid metal blanket or similar arrangements of a blanket structure. The MHD effects can significantly be reduced by means of electrical insulation of the flowing liquid metal against the structural material. The insulating material has to provide a resistivity of {>=} 25 {Omega}m, it has to be compatible with the liquid metal and should be sufficiently stable against irradiation damage and fracture due to thermal and mechanical cycling stresses. The liquid metal blanket fluid, Pb-17Li eutectic alloy, has the capacity to reduce the oxide layers which can be formed on austenitic and martensitic steels by means of high-temperature oxidation. It does not react with alumina in the temperature range of interest. Thus, the covering of structural material with alumina would be a solution of the problem of direct insulation of the structural material. Though several methods are known to cover steels with alumina layers, such methods do not appear to be feasible for the covering of the inner side of a large tubing system. The covering of the structural material with aluminum and the subsequent oxidation of this surface seems to open a way for the solution of this problem. Though the packing procedure of alitizing was known to offer a possibility to form surface layers rich in aluminum, the alternative method of hot-dip aluminizing was applied, since this procedure has the potential for the use in large dimensions and particularly for aluminizing inner sides of tubes.

  9. Ambient Dried Aerogels

    NASA Technical Reports Server (NTRS)

    Jones, Steven M.; Paik, Jong-Ah

    2013-01-01

    A method has been developed for creating aerogel using normal pressure and ambient temperatures. All spacecraft, satellites, and landers require the use of thermal insulation due to the extreme environments encountered in space and on extraterrestrial bodies. Ambient dried aerogels introduce the possibility of using aerogel as thermal insulation in a wide variety of instances where supercritically dried aerogels cannot be used. More specifically, thermoelectric devices can use ambient dried aerogel, where the advantages are in situ production using the cast-in ability of an aerogel. Previously, aerogels required supercritical conditions (high temperature and high pressure) to be dried. Ambient dried aerogels can be dried at room temperature and pressure. This allows many materials, such as plastics and certain metal alloys that cannot survive supercritical conditions, to be directly immersed in liquid aerogel precursor and then encapsulated in the final, dried aerogel. Additionally, the metalized Mylar films that could not survive the previous methods of making aerogels can survive the ambient drying technique, thus making multilayer insulation (MLI) materials possible. This results in lighter insulation material as well. Because this innovation does not require high-temperature or high-pressure drying, ambient dried aerogels are much less expensive to produce. The equipment needed to conduct supercritical drying costs many tens of thousands of dollars, and has associated running expenses for power, pressurized gasses, and maintenance. The ambient drying process also expands the size of the pieces of aerogel that can be made because a high-temperature, high-pressure system typically has internal dimensions of up to 30 cm in diameter and 60 cm in height. In the case of this innovation, the only limitation on the size of the aerogels produced would be in the ability of the solvent in the wet gel to escape from the gel network.

  10. Compression molding of aerogel microspheres

    DOEpatents

    Pekala, R.W.; Hrubesh, L.W.

    1998-03-24

    An aerogel composite material produced by compression molding of aerogel microspheres (powders) mixed together with a small percentage of polymer binder to form monolithic shapes in a cost-effective manner is disclosed. The aerogel composites are formed by mixing aerogel microspheres with a polymer binder, placing the mixture in a mold and heating under pressure, which results in a composite with a density of 50--800 kg/m{sup 3} (0.05--0.80 g/cc). The thermal conductivity of the thus formed aerogel composite is below that of air, but higher than the thermal conductivity of monolithic aerogels. The resulting aerogel composites are attractive for applications such as thermal insulation since fabrication thereof does not require large and expensive processing equipment. In addition to thermal insulation, the aerogel composites may be utilized for filtration, ICF target, double layer capacitors, and capacitive deionization. 4 figs.

  11. Compression molding of aerogel microspheres

    DOEpatents

    Pekala, Richard W. (Pleasant Hill, CA); Hrubesh, Lawrence W. (Pleasanton, CA)

    1998-03-24

    An aerogel composite material produced by compression molding of aerogel microspheres (powders) mixed together with a small percentage of polymer binder to form monolithic shapes in a cost-effective manner. The aerogel composites are formed by mixing aerogel microspheres with a polymer binder, placing the mixture in a mold and heating under pressure, which results in a composite with a density of 50-800 kg/m.sup.3 (0.05-0.80 g/cc). The thermal conductivity of the thus formed aerogel composite is below that of air, but higher than the thermal conductivity of monolithic aerogels. The resulting aerogel composites are attractive for applications such as thermal insulation since fabrication thereof does not require large and expensive processing equipment. In addition to thermal insulation, the aerogel composites may be utilized for filtration, ICF target, double layer capacitors, and capacitive deionization.

  12. THERMAL INSULATION PROPERTIES OF NONWOVEN SEMI-DISPOSABLE BLANKETS FROM RECYCLED POLYESTER/COTTON FIBERS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recycled polyester fibers and cotton fibers that require no chemical processing were used to produce a low-cost, semi-durable, nonwoven thermal blanket. Thermal blankets were given carboxylic acid finish to improve structural stability during use and laundering. A Steady-State Heat Flow meter FOX ...

  13. Advanced Aerogel Technology

    NASA Technical Reports Server (NTRS)

    Jones, Steven

    2013-01-01

    The JPL Aerogel Laboratory has made aerogels for NASA flight missions, e.g., Stardust, 2003 Mars Exploration Rovers and the 2011 Mars Science Laboratory, as well as NASA research projects for the past 14 years. During that time it has produced aerogels of a range of shapes, sizes, densities and compositions. Research is ongoing in the development of aerogels for future sample capture and return missions and for thermal insulation for both spacecraft and scientific instruments. For the past several years, the JPL Aerogel Laboratory has been developing, producing and testing a new composite material for use as the high temperature thermal insulation in the Advanced Sterling Radioisotope Generator (ASRG) being developed by Lockheed Martin and NASA. The composite is made up of a glass fiber felt, silica aerogel, Titania powder, and silica powder. The oxide powders are included to reduce irradiative heat transport at elevated temperatures. These materials have thermal conductivity values that are the same as the best commercially produced high temperature insulation materials, and yet are 40% lighter. By greatly reducing the amount of oxide powder in the composite, the density, and therefore for the value of the thermal conductivity, would be reduced. The JPL Aerogel Laboratory has experimented with using glass fiber felt, expanded glass fiber felt and loose fibers to add structural integrity to silica aerogels. However, this work has been directed toward high temperature applications. By conducting a brief investigation of the optimal combination of fiber reinforcement and aerogel density, a durable, extremely efficient thermal insulation material for ambient temperature applications would be produced. If a transparent thermal insulation is desired, then aerogel is an excellent candidate material. At typical ambient temperatures, silica aerogel prevents the transport of heat via convection and conduction due to its highly porous nature. To prevent irradiative thermal transport, silica aerogel can be used in conjunction with a transparent polymeric material that blocks infrared radiation. The transparency of silica aerogel is typically greater than 90% for visible wavelengths from 500 nm to 900 nm for a 5 mm long path length.

  14. Beta cloth durability assessment for Space Station Freedom (SSF) Multi-Layer Insulation (MLI) blanket covers

    NASA Technical Reports Server (NTRS)

    Koontz, Steven L.; Jacobs, Stephen; Le, Julie

    1993-01-01

    MLI blankets for the Space Station Freedom (SSF) must comply with general program requirements and recommendations for long life and durability in the low-Earth orbit (LEO) environment. Atomic oxygen and solar ultraviolet/vacuum ultraviolet are the most important factors in the SSF natural environment which affect materials life. Two types of Beta cloth (Teflon coated woven glass fabric), which had been proposed as MLI blanket covers, were tested for long-term durability in the LEO environment. General resistance to atomic oxygen attack and permeation were evaluated in the high velocity atomic oxygen beam system at Los Alamos National Laboratories. Long-term exposure to the LEO environment was simulated in the laboratory using a radio frequency oxygen plasma asher. The plasma asher treated Beta cloth specimens were tested for thermo-optical properties and mechanical durability. Space exposure data from the Long Duration Exposure Facility and the Intelsat Solar Array Coupon were also used in the durability assessment. Beta cloth fabricated to Rockwell specification MBO 135-027 (Chemglas 250) was shown to have acceptable durability for general use as an MLI blanket cover material in the LEO environment while Sheldahl G414500 should be used only in locations which are protected from direct Ram atomic oxygen.

  15. System and method for suppressing sublimation using opacified aerogel

    NASA Technical Reports Server (NTRS)

    Sakamoto, Jeff S. (Inventor); Snyder, G. Jeffrey (Inventor); Calliat, Thierry (Inventor); Fleurial, Jean-Pierre (Inventor); Jones, Steven M. (Inventor); Palk, Jong-Ah (Inventor)

    2008-01-01

    The present invention relates to a castable, aerogel-based, ultra-low thermal conductivity opacified insulation to suppress sublimation. More specifically, the present invention relates to an aerogel opacified with various opacifying or reflecting constituents to suppress sublimation and provide thermal insulation in thermoelectric modules. The opacifying constituent can be graded within the aerogel for increased sublimation suppression, and the density of the aerogel can similarly be graded to achieve optimal thermal insulation and sublimation suppression.

  16. Aerogel/polymer composite materials

    NASA Technical Reports Server (NTRS)

    Williams, Martha K. (Inventor); Smith, Trent M. (Inventor); Fesmire, James E. (Inventor); Roberson, Luke B. (Inventor); Clayton, LaNetra M. (Inventor)

    2010-01-01

    The invention provides new composite materials containing aerogels blended with thermoplastic polymer materials at a weight ratio of aerogel to thermoplastic polymer of less than 20:100. The composite materials have improved thermal insulation ability. The composite materials also have better flexibility and less brittleness at low temperatures than the parent thermoplastic polymer materials.

  17. Improvements to the Synthesis of Polyimide Aerogels

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B.; Nguyen, Baochau N.; Guo, Haiquan; Vivod, Stephanie; He, Zuhui; Malow, Ericka; Silva, Rebecca

    2011-01-01

    Cross-linked polyimide aerogels are viable approach to higher temperature, flexible insulation for inflatable decelerators. Results indicate that the all-polyimide aerogels are as strong or stronger than polymer reinforced silica aerogels at the same density. Currently, examining use of carbon nanofiber and clay nanoparticles to improve performance. Flexible, polyimide aerogels have potential utility in other applications such as space suits, habitats, shelter applications, etc. where low dusting is desired

  18. Mechanically Strong, Polymer Cross-linked Aerogels (X-Aerogels)

    NASA Technical Reports Server (NTRS)

    Leventis, Nicholas

    2006-01-01

    Aerogels comprise a class of low-density, high porous solid objects consisting of dimensionally quasi-stable self-supported three-dimensional assemblies of nanoparticles. Aerogels are pursued because of properties above and beyond those of the individual nanoparticles, including low thermal conductivity, low dielectric constant and high acoustic impedance. Possible applications include thermal and vibration insulation, dielectrics for fast electronics, and hosting of functional guests for a wide variety of optical, chemical and electronic applications. Aerogels, however, are extremely fragile materials, hence they have found only limited application in some very specialized environments, for example as Cerenkov radiation detectors in certain types of nuclear reactors, aboard spacecraft as collectors of hypervelocity particles (refer to NASA's Stardust program) and as thermal insulators on planetary vehicles on Mars (refer to Sojourner Rover in 1997 and Spirit and Opportunity in 2004). Along these lines, the X-Aerogel is a new NASA-developed strong lightweight material that has resolved the fragility problem of traditional (native) aerogels. X-Aerogels are made by applying a conformal polymer coating on the surfaces of the skeletal nanoparticles of native aerogels (see Scanning Electron Micrographs). Since the relative amounts of the polymeric crosslinker and the backbone are comparable, X-Aerogels can be viewed either as aerogels modified by the templated accumulation of polymer on the skeletal nanoparticles, or as nanoporous polymers made by remplated casting of polymer on a nanostructured framework. The most striking feature of X-Aerogels is that for a nominal 3-fold increase in density (still a ultralighweight material), the mechanical strength can be up to 300 times higher than the strength of the underlying native aerogel. Thus, X-Aerogels combine a multiple of the specific compressive strength of steel, with the the thermal conductivity of styrofoam. X-Aerogels have been demonstrated with several polymers such as polyurethanes/polyureas, epoxies and polyolefins, while crosslinking of approximately 35 different oxide aerogels yields a range of dimensionally stable, porous lightweight materials with unique combinations of structural, magnetic and optical properties. The main theme in materials development for space exploration is multifunction. For example, use of one material for thermal insulation/structural component will free weight for useful payload. In that regard, X-aerogels are evaluated at NASA for cryogenic fuel storage tanks and for spacesuits. Along the same lines, major impact fro X-Aerogels is also expected in commercial applications for thermal/acoustic insulation, in catalytic reformers and converters, in filtration membranes and membranes for fuel cells, as platforms for optical, electrical and magnetic sensors, and as lightweight structural component for aircraft and satellites.

  19. Aerogel: Tile Composites Toughen a Brittle Superinsulation

    NASA Technical Reports Server (NTRS)

    White, Susan; Rasky, Daniel; Arnold, James O. (Technical Monitor)

    1998-01-01

    Pure aerogels, though familiar in the laboratory for decades as exotic lightweight insulators with unusual physical properties, have had limited industrial applications due to their low strength and high brittleness. Composites formed of aerogels and the ceramic fiber matrices like those used as space shuttle tiles bypass the fragility of pure aerogels and can enhance the performance of space shuttle tiles in their harsh operating environment. Using a layer of aerogel embedded in a tile may open up a wide range of applications where thermal insulation, gas convection control and mechanical strength matter.

  20. Protective Skins for Aerogel Monoliths

    NASA Technical Reports Server (NTRS)

    Leventis, Nicholas; Johnston, James C.; Kuczmarski, Maria A.; Meador, Ann B.

    2007-01-01

    A method of imparting relatively hard protective outer skins to aerogel monoliths has been developed. Even more than aerogel beads, aerogel monoliths are attractive as thermal-insulation materials, but the commercial utilization of aerogel monoliths in thermal-insulation panels has been inhibited by their fragility and the consequent difficulty of handling them. Therefore, there is a need to afford sufficient protection to aerogel monoliths to facilitate handling, without compromising the attractive bulk properties (low density, high porosity, low thermal conductivity, high surface area, and low permittivity) of aerogel materials. The present method was devised to satisfy this need. The essence of the present method is to coat an aerogel monolith with an outer polymeric skin, by painting or spraying. Apparently, the reason spraying and painting were not attempted until now is that it is well known in the aerogel industry that aerogels collapse in contact with liquids. In the present method, one prevents such collapse through the proper choice of coating liquid and process conditions: In particular, one uses a viscous polymer precursor liquid and (a) carefully controls the amount of liquid applied and/or (b) causes the liquid to become cured to the desired hard polymeric layer rapidly enough that there is not sufficient time for the liquid to percolate into the aerogel bulk. The method has been demonstrated by use of isocyanates, which, upon exposure to atmospheric moisture, become cured to polyurethane/polyurea-type coats. The method has also been demonstrated by use of commercial epoxy resins. The method could also be implemented by use of a variety of other resins, including polyimide precursors (for forming high-temperature-resistant protective skins) or perfluorinated monomers (for forming coats that impart hydrophobicity and some increase in strength).

  1. Coated Aerogel Beads

    NASA Technical Reports Server (NTRS)

    Littman, Howard (Inventor); Plawsky, Joel L. (Inventor); Paccione, John D. (Inventor)

    2014-01-01

    Methods and apparatus for coating particulate material are provided. The apparatus includes a vessel having a top and a bottom, a vertically extending conduit having an inlet in the vessel and an outlet outside of the vessel, a first fluid inlet in the bottom of the vessel for introducing a transfer fluid, a second fluid inlet in the bottom of the vessel for introducing a coating fluid, and a fluid outlet from the vessel. The method includes steps of agitating a material, contacting the material with a coating material, and drying the coating material to produce a coated material. The invention may be adapted to coat aerogel beads, among other materials. A coated aerogel bead and an aerogel-based insulation material are also disclosed.

  2. Design Tool for Cryogenic Thermal Insulation Systems

    SciTech Connect

    Demko, Jonathan A [ORNL] [ORNL; Fesmire, J. E. [NASA Kennedy Space Center, Kennedy Space Center, Florida] [NASA Kennedy Space Center, Kennedy Space Center, Florida; Augustynowicz, S. D. [Sierra Lobo Inc., Kennedy Space Center, Florida] [Sierra Lobo Inc., Kennedy Space Center, Florida

    2008-01-01

    Thermal isolation of low-temperature systems from ambient environments is a constant issue faced by practitioners of cryogenics. For energy-efficient systems and processes to be realized, thermal insulation must be considered as an integrated system, not merely an add-on element. A design tool to determine the performance of insulation systems for comparative trade-off studies of different available material options was developed. The approach is to apply thermal analysis to standard shapes (plane walls, cylinders, spheres) that are relatively simple to characterize with a one-dimensional analytical or numerical model. The user describes the system hot and cold boundary geometry and the operating environment. Basic outputs such as heat load and temperature profiles are determined. The user can select from a built-in insulation material database or input user defined materials. Existing information has been combined with the new experimental thermal conductivity data produced by the Cryogenics Test Laboratory for cryogenic and vacuum environments, including high vacuum, soft vacuum, and no vacuum. Materials in the design tool include multilayer insulation, aerogel blankets, aerogel bulk-fill, foams, powders, composites, and other insulation system constructions. A comparison of the design tool to a specific composite thermal insulation system is given.

  3. Design Tool for Cryogenic Thermal Insulation Systems

    NASA Astrophysics Data System (ADS)

    Demko, J. A.; Fesmire, J. E.; Augustynowicz, S. D.

    2008-03-01

    Thermal isolation of low-temperature systems from ambient environments is a constant issue faced by practitioners of cryogenics. For energy-efficient systems and processes to be realized, thermal insulation must be considered as an integrated system, not merely an add-on element. A design tool to determine the performance of insulation systems for comparative trade-off studies of different available material options was developed. The approach is to apply thermal analysis to standard shapes (plane walls, cylinders, spheres) that are relatively simple to characterize with a one-dimensional analytical or numerical model. The user describes the system hot and cold boundary geometry and the operating environment. Basic outputs such as heat load and temperature profiles are determined. The user can select from a built-in insulation material database or input user defined materials. Existing information has been combined with the new experimental thermal conductivity data produced by the Cryogenics Test Laboratory for cryogenic and vacuum environments, including high vacuum, soft vacuum, and no vacuum. Materials in the design tool include multilayer insulation, aerogel blankets, aerogel bulk-fill, foams, powders, composites, and other insulation system constructions. A comparison of the design tool to a specific composite thermal insulation system is given.

  4. Aerogel Development

    NASA Technical Reports Server (NTRS)

    Sahai, Rashmi K.

    2005-01-01

    Aerogel is one of the most promising materials of the future. It's unique properties, including high porosity, transparency, very high thermal tolerance, and environmental friendliness give it the potential of replacing many different products used in society today. However, the market for aerogel is still very limited because of the cost of producing the material and its fragility. The principle objective of my project has been to find new ways to apply aerogel in order to increase its practicality and appeal to different aspects of society. More specifically, I have focused on finding different chemicals that will coat aerogel and increase its durability. Because aerogel is so fragile and will crumble under the pressure of most coatings this has been no easy task. However, by experimenting with many different coatings and combinations of aerogel properties, I have made several significant discoveries. Aerogel (ideally, high density and hydrophobic) can be coated with several acrylic polymers, including artist's gel and nail polish. These materials provide a protective layering around the aerogel and keep it from breaking as easily. Because fragility is one of the main reasons applications of aerogel are limited, these discoveries will hopefully aid in finding future applications for this extraordinary material.

  5. Improved Silica Aerogel Composite Materials

    NASA Technical Reports Server (NTRS)

    Paik, Jong-Ah; Sakamoto, Jeffrey; Jones, Steven

    2008-01-01

    A family of aerogel-matrix composite materials having thermal-stability and mechanical- integrity properties better than those of neat aerogels has been developed. Aerogels are known to be excellent thermal- and acoustic-insulation materials because of their molecular-scale porosity, but heretofore, the use of aerogels has been inhibited by two factors: (1) Their brittleness makes processing and handling difficult. (2) They shrink during production and shrink more when heated to high temperatures during use. The shrinkage and the consequent cracking make it difficult to use them to encapsulate objects in thermal-insulation materials. The underlying concept of aerogel-matrix composites is not new; the novelty of the present family of materials lies in formulations and processes that result in superior properties, which include (1) much less shrinkage during a supercritical-drying process employed in producing a typical aerogel, (2) much less shrinkage during exposure to high temperatures, and (3) as a result of the reduction in shrinkage, much less or even no cracking.

  6. Method for producing metal oxide aerogels

    DOEpatents

    Tillotson, T.M.; Poco, J.F.; Hrubesh, L.W.; Thomas, I.M.

    1995-04-25

    A two-step hydrolysis-condensation method was developed to form metal oxide aerogels of any density, including densities of less than 0.003g/cm{sup 3} and greater than 0.27g/cm{sup 3}. High purity metal alkoxide is reacted with water, alcohol solvent, and an additive to form a partially condensed metal intermediate. All solvent and reaction-generated alcohol is removed, and the intermediate is diluted with a nonalcoholic solvent. The intermediate can be stored for future use to make aerogels of any density. The aerogels are formed by reacting the intermediate with water, nonalcoholic solvent, and a catalyst, and extracting the nonalcoholic solvent directly. The resulting monolithic aerogels are hydrophobic and stable under atmospheric conditions, and exhibit good optical transparency, high clarity, and homogeneity. The aerogels have high thermal insulation capacity, high porosity, mechanical strength and stability, and require shorter gelation times than aerogels formed by conventional methods. 8 figs.

  7. Organic aerogel microspheres

    DOEpatents

    Mayer, S.T.; Kong, F.M.; Pekala, R.W.; Kaschmitter, J.L.

    1999-06-01

    Organic aerogel microspheres are disclosed which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonstick gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

  8. Organic aerogel microspheres

    DOEpatents

    Mayer, Steven T. (San Leandro, CA); Kong, Fung-Ming (Pleasanton, CA); Pekala, Richard W. (Pleasant Hill, CA); Kaschmitter, James L. (Pleasanton, CA)

    1999-01-01

    Organic aerogel microspheres which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonsticky gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

  9. Blanket technology experiments at Argonne National Laboratory

    SciTech Connect

    Mattas, R.F.; Reed, C.B.; Picologlou, B.; Finn, P.; Clemmer, R.; Porges, K.; Bennett, E.; Turner, L.R.

    1988-02-01

    Argonne National Laboratory has the largest US program for the development of blanket technology. The goals of the program are to resolve critical issues for different blanket concepts, to develop the understanding and predictive capability of blanket behavior, and to develop the technology needed to build and operate advanced fusion blankets. The projects within the program are liquid metal MHD, breeder neutronics, tritium oxidation, transient electromagnetics, FLIBE chemistry, and insulator coatings. The present status and recent results of the projects are described.

  10. Aerogel commercialization pilot project. Final program report

    SciTech Connect

    NONE

    1996-02-13

    Aerogels are extremely light weight, high surface area, very insulative materials that offer many potential improvements to commercial products. Aerogels have been the subject of extensive research at Department of Energy Laboratories and have been considered one of the technology most ready for commercialization. However, commercialization of the technology had been difficult for the National Laboratories since end users were not interested in the high temperature and high pressure chemical processes involved in manufacturing the raw material. Whereas, Aerojet as a supplier of rocket fuels, specialty chemicals and materials had the manufacturing facilities and experience to commercially produce aerogel-type products. Hence the TRP provided a link between the technology source (National Laboratories), the manufacturing (Aerojet) and the potential end users (other TRP partners). The program successfully produced approximately 500 ft{sup 2} of organic aerogel but failed to make significant quantities of silica aerogel. It is significant that this production represents both the largest volume and biggest pieces of organic aerogel ever produced. Aerogels, available from this program, when tested in several prototype commercial products were expected to improve the products performance, but higher than expected projected production costs for large scale manufacture of aerogels has limited continued commercial interest from these partners. Aerogels do, however, offer potential as a specialty material for some high value technology and defense products.

  11. Aerogel Composites for Aerospace Thermal Protection

    NASA Technical Reports Server (NTRS)

    White, Susan

    2003-01-01

    Aerogel composites formed by infiltrating organic and/or inorganic aerogels into fiber matrix materials enable us to exploit the low thermal conductivity and low density of aerogels while maintaining the strength, structure and other useful properties of a porous fiber matrix. New materials for extreme heating ranges are needed to insulate future spacecraft against the extreme heat of planetary atmospheric entry, but the insulation mass must be minimized in order to maximize the payload. A reusable system passively insulates to survive heating unchanged for relatively low heating. Ablators, which sacrifice mass to control heating, are used to protect vehicles against more extreme heating for a single use thermal protection system (TPS). Aerogel composites were fabricated and tested for spacecraft thermal protection. The high-temperaturey high heat flux tests described in this paper were performed in NASA Ames arc-jet facilities to simulate spacecraft atmospheric entry, and include heating conditions predicted for the forebody and backshell of the Mars Science Lander (MSL) entry probe. The aerogel composites tested showed excellent thermal performance in the arc-jet tests, functioning both as reusuable insulation under lower heat fluxes, and as ablative aerogels under the extreme heating predicted for the MSL forebody.

  12. Saddle Blanket

    USGS Multimedia Gallery

    This is one of many saddle blankets from Dr. J.D. Love. The blanket has some felt decoration along the edges and is in particularily good condition. Saddle Blankets were used under saddles or pack saddles to provide comfort for animals used to carry equipment. Object ID: USGS-000011...

  13. Flexible aerogel composite for mechanical stability and process of fabrication

    DOEpatents

    Coronado, Paul R. (Livermore, CA); Poco, John F. (Livermore, CA)

    1999-01-01

    A flexible aerogel and process of fabrication. An aerogel solution is mixed with fibers in a mold and allowed to gel. The gel is then processed by supercritical extraction, or by air drying, to produce a flexible aerogel formed to the shape of the mold. The flexible aerogel has excellent thermal and acoustic properties, and can be utilized in numerous applications, such as for energy absorption, insulation (temperature and acoustic), to meet the contours of aircraft shapes, and where space is limited since an inch of aerogel is a 4-5 times better insulator than an inch of fiberglass. The flexible aerogel may be of an inorganic (silica) type or an organic (carbon) type, but containing fibers, such as glass or carbon fibers.

  14. Flexible aerogel composite for mechanical stability and process of fabrication

    DOEpatents

    Coronado, Paul R. (Livermore, CA); Poco, John F. (Livermore, CA)

    2000-01-01

    A flexible aerogel and process of fabrication. An aerogel solution is mixed with fibers in a mold and allowed to gel. The gel is then processed by supercritical extraction, or by air drying, to produce a flexible aerogel formed to the shape of the mold. The flexible aerogel has excellent thermal and acoustic properties, and can be utilized in numerous applications, such as for energy absorption, insulation (temperature and acoustic), to meet the contours of aircraft shapes, and where space is limited since an inch of aerogel is a 4-5 times better insulator than an inch of fiberglass. The flexible aerogel may be of an inorganic (silica) type or an organic (carbon) type, but containing fibers, such as glass or carbon fibers.

  15. Nearly Seamless Vacuum-Insulated Boxes

    NASA Technical Reports Server (NTRS)

    Stepanian, Christopher J.; Ou, Danny; Hu, Xiangjun

    2010-01-01

    A design concept, and a fabrication process that would implement the design concept, have been proposed for nearly seamless vacuum-insulated boxes that could be the main structural components of a variety of controlled-temperature containers, including common household refrigerators and insulating containers for shipping foods. In a typical case, a vacuum-insulated box would be shaped like a rectangular parallelepiped conventional refrigerator box having five fully closed sides and a hinged door on the sixth side. Although it is possible to construct the five-closed-side portion of the box as an assembly of five unitary vacuum-insulated panels, it is not desirable to do so because the relatively high thermal conductances of the seams between the panels would contribute significant amounts of heat leakage, relative to the leakage through the panels themselves. In contrast, the proposal would make it possible to reduce heat leakage by constructing the five-closed-side portion of the box plus the stationary portion (if any) of the sixth side as a single, seamless unit; the only remaining seam would be the edge seal around the door. The basic cross-sectional configuration of each side of a vacuum-insulated box according to the proposal would be that of a conventional vacuum-insulated panel: a low-density, porous core material filling a partially evacuated space between face sheets. However, neither the face sheets nor the core would be conventional. The face sheets would be opposite sides of a vacuum bag. The core material would be a flexible polymer-modified silica aerogel of the type described in Silica/Polymer and Silica/Polymer/Fiber Composite Aero - gels (MSC-23736) in this issue of NASA Tech Briefs. As noted in that article, the stiffness of this core material against compression is greater than that of prior aerogels. This is an important advantage because it translates to greater retention of thickness and, hence, of insulation performance when pressure is applied across the thickness, in particular, when the space between the face sheets is evacuated, causing the core material to be squeezed between the face sheets by atmospheric pressure. Fabrication of a typical vacuum-insulated box according to the proposal would begin with fabrication of a cross-shaped polymer-modified aerogel blanket. The dimensions of the cross would be chosen so that (1) the central rectangular portion of the cross would form the core for the back of the box and (2) the arms of the cross could be folded 90 from the back plane to form the cores of the adjacent four sides of the box. Optionally, the blanket could include tabs for joining the folded sides of the blanket along mating edges and tabs that could serve as hinges for the door. Vacuum bags in the form of similar five-sided boxes would be made of a suitable polymeric film, one bag to fit the outer core surface, the other to fit the inner core surface. By use of commercially available film-sealing equipment, these box-shaped bags would be seamed together to form a single vacuum bag encasing the box-shaped core. Also, a one-way valve would be sealed to the bag. Through this valve, the interior of the bag would be evacuated to a pressure between 1 and 10 torr (approximately between 0.13 and 1.3 kPa). The polymer-modified aerogel core material is known to perform well as a thermal insulator in such a partial vacuum.

  16. Novel load responsive multilayer insulation with high in-atmosphere and on-orbit thermal performance

    NASA Astrophysics Data System (ADS)

    Dye, S.; Kopelove, A.; Mills, G. L.

    2012-04-01

    Aerospace cryogenic systems require lightweight, high performance thermal insulation to preserve cryopropellants both pre-launch and on-orbit. Current technologies have difficulty meeting all requirements, and advances in insulation would benefit cryogenic upper stage launch vehicles, LH2 fueled aircraft and ground vehicles, and provide capabilities for sub-cooled cryogens for space-borne instruments and orbital fuel depots. This paper reports the further development of load responsive multilayer insulation (LRMLI) that has a lightweight integrated vacuum shell and provides high thermal performance both in-air and on-orbit. LRMLI is being developed by Quest Product Development and Ball Aerospace under NASA contract, with prototypes designed, built, installed and successfully tested. A 3-layer LRMLI blanket (0.63 cm thick, 77 K cold, 295 K hot) had a measured heat leak of 6.6 W/m2 in vacuum and 40.6 W/m2 in air at one atmosphere. In-air LRMLI has an 18× advantage over Spray On Foam Insulation (SOFI) in heat leak per thickness and a 16× advantage over aerogel. On-orbit LRMLI has a 78× lower heat leak than SOFI per thickness and 6× lower heat leak than aerogel. The Phase II development of LRMLI is reported with a modular, flexible, thin vacuum shell and improved on-orbit performance. Structural and thermal analysis and testing results are presented. LRMLI mass and thermal performance is compared to SOFI, aerogel and MLI over SOFI.

  17. Functionalized aerogels - new nanomaterials for energy-efficient building. Preliminary AFM, Nanoidentation and EIS studies

    Microsoft Academic Search

    G. R. Ivanov; R. Tomova; S. T. Djambova; M. Nadoliiski; D. Dimova-Malinovska

    2010-01-01

    Aerogels are highly porous nanostructured materials with excellent thermal insulation properties. The possibility to add additional function - to functionalize the aerogels, especially to produce photovoltaic electricity, will make them an excellent candidate for energy-efficient building. Going in the direction of this midterm goal we start with the investigation of the properties of the readily available silica aerogels. Atomic Force

  18. Synthesis, Processing, and Characterization of Inorganic-Organic Hybrid Cross-Linked Silica, Organic Polyimide, and Inorganic Aluminosilicate Aerogels

    NASA Technical Reports Server (NTRS)

    Nguyen, Baochau N.; Guo, Haiquan N.; McCorkle, Linda S.

    2014-01-01

    As aerospace applications become ever more demanding, novel insulation materials with lower thermal conductivity, lighter weight and higher use temperature are required to fit the aerospace application needs. Having nanopores and high porosity, aerogels are superior thermal insulators, among other things. The use of silica aerogels in general is quite restricted due to their inherent fragility, hygroscopic nature, and poor mechanical properties, especially in extereme aerospace environments. Our research goal is to develop aerogels with better mechanical and environmental stability for a variety of aeronautic and space applications including space suit insulation for planetary surface missions, insulation for inflatable structures for habitats, inflatable aerodynamic decelerators for entry, descent and landing (EDL) operations, and cryotank insulation for advance space propulsion systems. Different type of aerogels including organic-inorganic polymer reinforced (hybrid) silica-based aerogels, polyimide aerogels and inorganic aluminosilicate aerogels have been developed and examined.

  19. Applications for silica-based aerogel products on an industrial scale

    SciTech Connect

    Schmidt, M.; Schwertfeger, F. [Hoechst Research and Technology Deutschland GmbH and Co., Frankfurt/Main (Germany)

    1998-12-31

    Aerogels, nanoporous lightweight materials, were discovered more than 60 years ago. The supercritical manufacturing process and expensive raw materials typically used to produce aerogels prohibited commercialization on an industrial scale. Recently a commercially attractive ambient pressure production process was developed which will allow broader commercialization of silica-aerogel products. Some aerogel products for insulation applications and their preparation are described. Sound insulation properties including a remarkable absorption in the difficult low frequency range was found. In the case of insulation plates performance depends on binder and can be positively influenced by choosing the right binding material.

  20. Insulation.

    ERIC Educational Resources Information Center

    Rhea, Dennis

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with insulation. Its objective is for the student to be able to determine insulation needs of new or existing structures, select type to use, use installation techniques, calculate costs, and apply safety factors. Some topics covered…

  1. Particle Tracks in Aerogel

    NASA Technical Reports Server (NTRS)

    2005-01-01

    In an experiment using a special air gun, particles are shot into aerogel at high velocities. Closeup of particles that have been captured in aerogel are shown here. The particles leave a carrot-shaped trail in the aerogel. Aerogel was used on the Stardust spacecraft to capture comet particles from Comet Wild 2.

  2. Surface modified aerogel monoliths

    NASA Technical Reports Server (NTRS)

    Leventis, Nicholas (Inventor); Johnston, James C. (Inventor); Kuczmarski, Maria A. (Inventor); Meador, Mary Ann B. (Inventor)

    2013-01-01

    This invention comprises reinforced aerogel monoliths such as silica aerogels having a polymer coating on its outer geometric surface boundary, and to the method of preparing said aerogel monoliths. The polymer coatings on the aerogel monoliths are derived from polymer precursors selected from the group consisting of isocyanates as a precursor, precursors of epoxies, and precursors of polyimides. The coated aerogel monoliths can be modified further by encapsulating the aerogel with the polymer precursor reinforced with fibers such as carbon or glass fibers to obtain mechanically reinforced composite encapsulated aerogel monoliths.

  3. Aerogel/Particle Composites for Thermoelectric Devices

    NASA Technical Reports Server (NTRS)

    Paik, Jong-Ah; Sakamoto, Jeffrey; Jones, Steven

    2006-01-01

    Optimizing solution chemistry and the addition of titania and fumed silica powder reduces shrinkage. These materials would serve to increase thermal efficiency by providing thermal insulation to suppress lateral heat leaks. They would also serve to prolong operational lifetime by suppressing sublimation of certain constituents of thermoelectric materials (e.g., sublimation of Sb from CoSb3) at typical high operating temperatures. [The use of pure silica aerogels as cast-in-place thermal-insulation and sublimation-suppression materials was described in "Aerogels for Thermal Insulation of Thermoelectric Devices" (NPO-40630), NASA Tech Briefs, Vol. 30, No. 7 (July 2006), page 50.] A silica aerogel is synthesized in a solgel process that includes preparation of a silica sol, gelation of the sol, and drying of the gel in a solvent at a supercritical temperature and pressure. The utility of pure silica aerogel is diminished by a tendency to shrink (and, therefore, also to crack) during the gelation and supercritical-drying stages. Moreover, to increase suppression of sublimation, it is advantageous to make an aerogel having greater density, but shrinkage and cracking tend to increase with density. A composite material of the type under investigation consists mostly of titania oxide powder particles and a small addition of fumed silica powder, which are mixed into the sol along with other ingredients prior to the gelation stage of processing. The silica aerogel and fumed silica act as a binder, gluing the titania particles together. It is believed that the addition of fumed silica stiffens the aerogel network and reduces shrinkage during the supercritical-drying stage. Minimization of shrinkage enables establishment of intimate contact between thermoelectric legs and the composite material, thereby maximizing the effectiveness of the material for thermal insulation and suppression of sublimation. To some extent, the properties of the composite can be tailored via the proportions of titania and other ingredients. In particular (see figure), the addition of a suitably large proportion of titania (e.g., 0.6 g/cu cm) along with a 10-percent increase in the amount of tetraethylorthosilicate [TEOS (an ingredient of the sol)] to an aerogel component having a density 40 mg/cm3makes it possible to cast a high-average-density (>0.1 g/cm3) aerogel/particle composite having low shrinkage (2.3 percent).

  4. Blanket technology experiments at Argonne National Laboratory

    NASA Astrophysics Data System (ADS)

    Mattas, R. F.; Reed, C. B.; Picologlou, B.; Finn, P.; Clemmer, R.; Porges, K.; Bennett, E.; Turner, L. R.

    1988-02-01

    Argonne National Laboratory has the largest U.S. program for the development of blanket technology. The goals of the program are to resolve critical issues for different blanket concepts, to develop the understanding and predictive capability of blanket behavior, and to develop the technology needed to build and operate advanced fusion blankets. The projects within the program are liquid metal MHD, breeder neutronics, tritium oxidation, transient electromagnetics, FLIBE chemistry, and insulator coatings. The present status and recent results of the projects are described.

  5. EVALUATION OF THE TUNGSTEN ALLOY VAPORIZING LITHIUM FIRST WALL AND BLANKET CONCEPT

    E-print Network

    California at Los Angeles, University of

    ;269-00/rs Transpiration Cooled First Wall and Blanket Concept (Poloidal flow FW) (A) (B)Blanket plate Side A critical concept for both boiling trays and transpiration cooled blanket options Design Criteria: Capillary lithium flow rate implies MHD insulator coating is not required at the first wall and blanket #12

  6. APEX-TASK IV (A W-alloy structure, vaporized Li blanket concept)

    E-print Network

    California at Los Angeles, University of

    /blanket configuration · Blanket lithium boiling analysis · First Wall/Blanket Li transpiration cooling analysis for both boiling trays and transpiration cooled blanket options. Continuing work to November 2000: 1 lithium flow rate implies MHD insulator coating is not required. Task summary presented at the July 2000

  7. Highly Insulating Windows with a U-value less than 0.6 W/m2K

    SciTech Connect

    Wendell Rhine; Ying Tang; Wenting Dong; Roxana Trifu; Reduane Begag

    2008-11-30

    U.S. households rely primarily on three sources of energy: natural gas, electricity, and fuel oil. In the past several decades, electricity consumption by households has grown dramatically, and a significant portion of electricity used in homes is for lighting. Lighting includes both indoor and outdoor lighting and is found in virtually every household in the United States. In 2001, according to the US Energy Information Administration, lighting accounted for 101 billion kWh (8.8 percent) of U.S. household electricity use. Incandescent lamps, which are commonly found in households, are highly inefficient sources of light because about 90 percent of the energy used is lost as heat. For that reason, lighting has been one focus area to increase the efficiency of household electricity consumption. Windows have several functions, and one of the main functions is to provide a view to the outside. Daylighting is another one of windows main functions and determines the distribution of daylight to a space. Daylighting windows do not need to be transparent, and a translucent daylighting window is sufficient, and often desired, to diffuse the light and make the space more environmentally pleasing. In homes, skylights are one source of daylighting, but skylights are not very energy efficient and are inseparably linked to solar heat gain. In some climates, added solar heat gains from daylighting may be welcome; but in other climates, heat gain must be controlled. More energy efficient skylights and daylighting solutions, in general, are desired and can be designed by insulating them with aerogels. Aerogels are a highly insulating and transparent material in its pure form. The overall objective for this project was to prepare an economical, translucent, fiber-reinforced aerogel insulation material for daylighting applications that is durable for manufacturing purposes. This advanced insulation material will increase the thermal performance of daylighting windows, while satisfying constraints such as durability, cost, user acceptance, size limits, and environmental safety concerns. The energy efficient daylighting window will consist of a translucent and resilient aerogel panel sandwiched between glass panes in double glazed windows. Compared to the best windows available today, the double glazed translucent windows with 1/2-inch aerogel inserts will have a U-value of 1.2 W/m{sup 2} K (0.211 BTU/ft{sup 2} h F) without any coating or low conductivity fill gases. These windows will be more effective than the windows with an Energy Star rating of U-2 W/m{sup 2} K and could be made even more efficient by using low-e coated glass glazings and inert gas fills. This report summarizes the work accomplished on Cooperative Agreement DE-FC26-03NT41950. During this project, Aspen Aerogels made transparent and translucent aerogels from TMOS and TEOS. We characterized the transparency of the aerogels, reinforced the transparent aerogels with fibers and prepared large translucent aerogel panels and blankets. We also conducted an initial market study for energy efficient translucent windows. A lab-scale process was developed that could be scaled-up to manufacture blankets of these translucent aerogels. The large blankets prepared were used to fabricate prototype translucent windows and skylights. The primary goal of this project was to develop transparent, resilient, hydrophobic silica aerogels that have low thermal conductivities (R-10/inch) to be used to produce aerogel insulated double-glazing windows with a U value of 0.6 W/m{sup 2}K. To meet this objective we developed a process and equipment to produce blankets of translucent, hydrophobic aerogel. We focused on silica, organically-modified silica aerogels (Ormosils), and fiber reinforced silica aerogels due to the appreciable expertise in silica sol-gel processing available with the personnel at Aspen Aerogels, and also due to the quantity of knowledge available in the scientific literature. The project was conducted in three budget periods, herein called BP1, BP2 and BP3.

  8. Mechanically Strong Lightweight Materials for Aerospace Applications (x-aerogels)

    NASA Technical Reports Server (NTRS)

    Leventis, Nicholas

    2005-01-01

    The X-Aerogel is a new NASA-developed strong lightweight material made by reacting the mesoporous surfaces of 3-D networks of inorganic nanoparticles with polymeric crosslinkers. Since the relative amount of the crosslinker and the backbone are comparable, X-Aerogels can be viewed either as aerogels modified by templated accumulation of polymer on the skeletal nanoparticles, or as nanoporous polymers made by templated casting of polymeric precursors on a nanostructured framework. The most striking feature of X-Aerogels is that for a nominal 3-fold increase in density (still a ultralightweight material), the mechanical strength can be up to 300 times higher than the strength of the underlying native aerogel. Thus, X-Aerogels combine a multiple of the specific compressive strength of steel, with the thermal conductivity of styrofoam. XAerogels have been demonstrated with several polymers such as polyurethanes/polyureas, epoxies and polyolefins, while crosslinking of approximately 35 different oxide aerogels yields a wide variety of dimensionally stable, porous lightweight materials with interesting structural, magnetic and optical properties. X-Aerogels are evaluated for cryogenic rocket fuel storage tanks and for Advanced EVA suits, where they will play the dual role of the thermal insulator/structural material. Along the same lines, major impact is also expected by the use of X-Aerogels in structural components/thermal protection for small satellites, spacecrafts, planetary vehicles and habitats.

  9. Aerogel in Hand

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Though ghostly in appearance like an hologram, aerogel is very solid. It feels like hard styrofoam to the touch. Aerogel was used on the Stardust spacecraft to capture comet particles from Comet Wild 2.

  10. Influence of Boehmite Precursor on Aluminosilicate Aerogel Pore Structure, Phase Stability and Resistance to Densification at High Temperatures

    NASA Technical Reports Server (NTRS)

    Hurwitz, Frances I.; Guo, Haiquan; Newlin, Katy N.

    2011-01-01

    Aluminosilicate aerogels are of interest as constituents of thermal insulation systems for use at temperatures higher than those attainable with silica aerogels. It is anticipated that their effectiveness as thermal insulators will be influenced by their morphology, pore size distribution, physical and skeletal densities. The present study focuses on the synthesis of aluminosilicate aerogel from a variety of Boehmite (precursors as the Al source, and tetraethylorthosilicate (TEOS) as the Si source, and the influence of starting powder on pore structure and thermal stability.

  11. Aerogel-lo

    NSDL National Science Digital Library

    NASA

    1999-01-01

    This demonstration (on pages 9-11) uses gelatin and lead pellets to model how aerogel, a technology used by NASA spacecrafts, is used to capture comet particles. Instructions are provided on how to test the consistency of the gelatin "aerogel-lo", which must be prepared beforehand, and tips for running the demo. The procedure also includes background info about aerogel (first discovered in the 1930s), and limits of the "aerogel-lo" model, which is far more dense than real aerogel. Reflection questions are listed at the end.

  12. Polyimide Aerogel Thin Films

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann; Guo, Haiquan

    2012-01-01

    Polyimide aerogels have been crosslinked through multifunctional amines. This invention builds on "Polyimide Aerogels With Three-Dimensional Cross-Linked Structure," and may be considered as a continuation of that invention, which results in a polyimide aerogel with a flexible, formable form. Gels formed from polyamic acid solutions, end-capped with anhydrides, and cross-linked with the multifunctional amines, are chemically imidized and dried using supercritical CO2 extraction to give aerogels having density around 0.1 to 0.3 g/cubic cm. The aerogels are 80 to 95% porous, and have high surface areas (200 to 600 sq m/g) and low thermal conductivity (as low as 14 mW/m-K at room temperature). Notably, the cross-linked polyimide aerogels have higher modulus than polymer-reinforced silica aerogels of similar density, and can be fabricated as both monoliths and thin films.

  13. Carbon nanomaterials in silica aerogel matrices

    SciTech Connect

    Hamilton, Christopher E [Los Alamos National Laboratory; Chavez, Manuel E [Los Alamos National Laboratory; Duque, Juan G [Los Alamos National Laboratory; Gupta, Gautam [Los Alamos National Laboratory; Doorn, Stephen K [Los Alamos National Laboratory; Dattelbaum, Andrew M [Los Alamos National Laboratory; Obrey, Kimberly A D [Los Alamos National Laboratory

    2010-01-01

    Silica aerogels are ultra low-density, high surface area materials that are extremely good thermal insulators and have numerous technical applications. However, their mechanical properties are not ideal, as they are brittle and prone to shattering. Conversely, single-walled carbon nanotubes (SWCNTs) and graphene-based materials, such as graphene oxide, have extremely high tensile strength and possess novel electronic properties. By introducing SWCNTs or graphene-based materials into aerogel matrices, it is possible to produce composites with the desirable properties of both constituents. We have successfully dispersed SWCNTs and graphene-based materials into silica gels. Subsequent supercritical drying results in monolithic low-density composites having improved mechanical properties. These nanocomposite aerogels have great potential for use in a wide range of applications.

  14. Uncooled thin film pyroelectric IR detector with aerogel thermal isolation

    DOEpatents

    Ruffner, Judith A. (Albuquerque, NM); Bullington, Jeff A. (Albuquerque, NM); Clem, Paul G. (Albuquerque, NM); Warren, William L. (Albuquerque, NM); Brinker, C. Jeffrey (Albuquerque, NM); Tuttle, Bruce A. (Albuquerque, NM); Schwartz, Robert W. (Seneca, SC)

    1999-01-01

    A monolithic infrared detector structure which allows integration of pyroelectric thin films atop low thermal conductivity aerogel thin films. The structure comprises, from bottom to top, a substrate, an aerogel insulating layer, a lower electrode, a pyroelectric layer, and an upper electrode layer capped by a blacking layer. The aerogel can offer thermal conductivity less than that of air, while providing a much stronger monolithic alternative to cantilevered or suspended air-gap structures for pyroelectric thin film pixel arrays. Pb(Zr.sub.0.4 Ti.sub.0.6)O.sub.3 thin films deposited on these structures displayed viable pyroelectric properties, while processed at 550.degree. C.

  15. Clay Nanocomposite/Aerogel Sandwich Structures for Cryotanks

    NASA Technical Reports Server (NTRS)

    Miller, Sandi; Leventis, Nicholas; Johnston, J. Chris; Meador, Michael

    2006-01-01

    GRC research has led to the development of epoxy-clay nanocomposites with 60-70% lower gas permeability than the base epoxy resin. Filament wound carbon fiber reinforced tanks made with this nanocomposite had a five-fold lower helium leak rate than the corresponding tanks made without clay. More recent work has produced new composites with more than a 100-fold reduction in helium permeability. Use of these advanced, high barrier composites would eliminate the need for a liner in composite cryotanks, thereby simplifying construction and reducing propellant leakage. Aerogels are attractive materials for use as cryotank insulation because of their low density and low thermal conductivity. However, aerogels are fragile and have poor environmental stability, which have limited their use to certain applications in specialized environments (e.g., in certain types of nuclear reactors as Cerenkov radiation detectors, and as thermal insulators aboard space rovers on Mars). New GRC developed polymer crosslinked aerogels (X-Aerogels) retain the low density of conventional aerogels, but they demonstrate a 300-fold increase in their mechanical strength. Currently, our strongest materials combine a density of approx. 0.45 g/cc, a thermal conductivity of approx. 0.04 W/mK and a compressive strength of 185 MPa. Use of these novel aerogels as insulation materials/structural components in combination with the low permeability of epoxy-clay nanocomposites could significantly reduce cryotank weight and improve durability.

  16. Studying the properties of Aerogel at Marshall Space Flight Center

    NASA Technical Reports Server (NTRS)

    1996-01-01

    NASA scientists at Marshall Space Flight Center are collaborating with scientists at the Lawrence Berkeley National Laboratory on an experiment in space with a fascinating material called Aerogel. Aerogel is the lightest solid material known - only three times the density of air - and has tremendous insulating capability. In its current smoky form, Aerogel can be used to insulate the walls of houses and engine compartments of cars. It was also used in the space program as insulating material on the rover, Sojourner, aboard the Mars Pathfinder. Because Aerogel has a smoky appearance, its current usages are limited. However, NASA researchers believe that by taking this research to space, they can resolve the problem of making Aerogel transparent enough to see clearly through. So far, recent space experiments have been encouraging. The samples produced in microgravity indicate a change in the microstructure of the material as compared to ground samples. MSFC scientists continue to study the effects of microgravity on Aerogel as their research in space continues.

  17. In Vivo Ultrasonic Detection of Polyurea Crosslinked Silica Aerogel Implants

    PubMed Central

    Sabri, Firouzeh; Sebelik, Merry E.; Meacham, Ryan; Boughter, John D.; Challis, Mitchell J.; Leventis, Nicholas

    2013-01-01

    Background Polyurea crosslinked silica aerogels are highly porous, lightweight, and mechanically strong materials with great potential for in vivo applications. Recent in vivo and in vitro studies have demonstrated the biocompatibility of this type of aerogel. The highly porous nature of aerogels allows for exceptional thermal, electric, and acoustic insulating capabilities that can be taken advantage of for non-invasive external imaging techniques. Sound-based detection of implants is a low cost, non-invasive, portable, and rapid technique that is routinely used and readily available in major clinics and hospitals. Methodology In this study the first in vivo ultrasound response of polyurea crosslinked silica aerogel implants was investigated by means of a GE Medical Systems LogiQe diagnostic ultrasound machine with a linear array probe. Aerogel samples were inserted subcutaneously and sub-muscularly in a) fresh animal model and b) cadaveric human model for analysis. For comparison, samples of polydimethylsiloxane (PDMS) were also imaged under similar conditions as the aerogel samples. Conclusion/significance Polyurea crosslinked silica aerogel (X-Si aerogel) implants were easily identified when inserted in either of the regions in both fresh animal model and cadaveric model. The implant dimensions inferred from the images matched the actual size of the implants and no apparent damage was sustained by the X-Si aerogel implants as a result of the ultrasonic imaging process. The aerogel implants demonstrated hyperechoic behavior and significant posterior shadowing. Results obtained were compared with images acquired from the PDMS implants inserted at the same location. PMID:23799093

  18. Method of manufacturing aerogel composites

    DOEpatents

    Cao, W.; Hunt, A.J.

    1999-03-09

    Disclosed herewith is a process of forming an aerogel composite which comprises introducing a gaseous material into a formed aerogel monolith or powder, and causing decomposition of said gaseous material in said aerogel in amounts sufficient to cause deposition of the decomposition products of the gas on the surfaces of the pores of the said aerogel.

  19. Method of manufacturing aerogel composites

    DOEpatents

    Cao, Wanqing (Alameda, CA); Hunt, Arlon Jason (Oakland, CA)

    1999-01-01

    Disclosed herewith is a process of forming an aerogel composite which comprises introducing a gaseous material into a formed aerogel monolith or powder, and causing decomposition of said gaseous material in said aerogel in amounts sufficient to cause deposition of the decomposition products of the gas on the surfaces of the pores of the said aerogel.

  20. Comet Ejecta in Aerogel

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Click on image for annotated image

    This image shows a particle impact on the aluminum frame that holds the aerogel tiles. The debris from the impact shot into the adjacent aerogel tile producing the explosion pattern of ejecta framents captured in the material. A nice cratering experiment.

  1. Melamine-formaldehyde aerogels

    DOEpatents

    Pekala, Richard Walter (Pleasant Hill, CA)

    1992-01-01

    Organic aerogels that are transparent and essentially colorless are prepa from the aqueous, sol-gel polymerization of melamine with formaldehyde. The melamine-formaldehyde (MF) aerogels have low densities, high surface areas, continuous porsity, ultrafine cell/pore sizes, and optical clarity.

  2. Melamine-formaldehyde aerogels

    DOEpatents

    Pekala, R.W.

    1992-01-14

    Organic aerogels that are transparent and essentially colorless are prepared from the aqueous, sol-gel polymerization of melamine with formaldehyde. The melamine-formaldehyde (MF) aerogels have low densities, high surface areas, continuous porosity, ultrafine cell/pore sizes, and optical clarity. 3 figs.

  3. Automotive Insulation

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Under a Space Act Agreement between Boeing North America and BSR Products, Space Shuttle Thermal Protection System (TPS) materials are now used to insulate race cars. BSR has created special TPS blanket insulation kits for use on autos that take part in NASCAR events, and other race cars through its nationwide catalog distribution system. Temperatures inside a race car's cockpit can soar to a sweltering 140 to 160 degrees, with the extreme heat coming through the engine firewall, transmission tunnel, and floor. It is common for NASCAR drivers to endure blisters and burns due to the excessive heat. Tests on a car insulated with the TPS material showed a temperature drop of some 50 degrees in the driver's cockpit. BSR-TPS Products, Inc. now manufactures insulation kits for distribution to race car teams around the world.

  4. Assessment of Cumulative Trauma Disorder (CTD) Risk for 3 Different Tasks Constructing and Repairing Multi-Layer Insulation (MLI) Blankets, Preparing the Dough for a Pizza, and Operating the Becton-Dickinson FACSAria Flow Cytometer

    NASA Technical Reports Server (NTRS)

    Gentzler, Marc; Kline, Martin; Palmer, Andrew; Terrone, Mark

    2007-01-01

    The Cumulative Trauma Disorder (CTD) risks for three different tasks using McCauley-Bell and Badiru's (1993) formula based on task, personal, and organizational factors were examined. For the Multi-Layer Insulation (MLI) blanket task, the results showed that the task, personal, and organizational risks were at about the same level. The personal risk factors for this task were evaluated using a hypothetical female employee age 52. For the pizza dough task, it was shown that the organizational risk was particularly high, with task related factors also at quite dangerous levels. On the other hand, there was a very low level of personal risk factors, based on a female age 17. The flow cytometer task was assessed with three different participants, a11 of whom had quite disparate levels of personal risk, which slightly affected the overall CTD risk. This reveals how individual difference variables certainly need to be considered. The task and organizational risks for this task were rated at about the same moderate level. The overall CTD risk averaged across the three participants was .335, indicating some risk. Compruing across the tasks revealed that the pizza dough task created the greatest overall CTD risk by far (.568), with the MLI (.325) and flow cytometer task (.335) having some risk associated with them. Future research should look into different tasks for more of a comparison

  5. Cryogenic Insulation Systems

    NASA Technical Reports Server (NTRS)

    Augustynowicz, S. D.; Fesmire, J. E.; Wikstrom, J. P.

    1999-01-01

    The results of a comparative study of cryogenic insulation systems performed are presented. The key aspects of thermal insulation relative to cryogenic system design, testing, manufacturing, and maintenance are discussed. An overview of insulation development from an energy conservation perspective is given. Conventional insulation materials for cryogenic applications provide three levels of thermal conductivity. Actual thermal performance of standard multilayer insulation (MLI) is several times less than laboratory performance and often 10 times worse than ideal performance. The cost-effectiveness of the insulation system depends on thermal performance; flexibility and durability; ease of use in handling, installation, and maintenance; and overall cost including operations, maintenance, and life cycle. Results of comprehensive testing of both conventional and novel materials such as aerogel composites using cryostat boil-off methods are given. The development of efficient, robust cryogenic insulation systems that operate at a soft vacuum level is the primary focus of this paper.

  6. Organic aerogel microspheres and fabrication method therefor

    DOEpatents

    Mayer, Steven T. (San Leandro, CA); Kong, Fung-Ming (Pleasanton, CA); Pekala, Richard W. (Pleasant Hill, CA); Kaschmitter, James L. (Pleasanton, CA)

    1996-01-01

    Organic aerogel microspheres which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonsticky gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

  7. Organic aerogel microspheres and fabrication method therefor

    DOEpatents

    Mayer, S.T.; Kong, F.M.; Pekala, R.W.; Kaschmitter, J.L.

    1996-04-16

    Organic aerogel microspheres which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonsticky gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

  8. Aerogels in Catalysis

    Microsoft Academic Search

    MICHAEL SCHNEIDER; ALFONS BAIKER

    1995-01-01

    Aerogels offer interesting opportunities for catalysis due to their unique morphological and chemical properties. These properties originate from their wet-chemical preparation by the solution-sol-gel (SSG) method and their subsequent liberation from the solvent via critical-point drying or supercritical (or hypercritical) drying (SCD). Due to the “structure-preserving” ability of SCD, the usually oxidic (or metallic) aerogels are solids of high porosity

  9. Comparative study of aerogels obtained from differently prepared nanocellulose fibers.

    PubMed

    Chen, Wenshuai; Li, Qing; Wang, Youcheng; Yi, Xin; Zeng, Jie; Yu, Haipeng; Liu, Yixing; Li, Jian

    2014-01-01

    This article describes the fabrication of nanocellulose fibers (NCFs) with different morphologies and surface properties from biomass resources as well as their self-aggregation into lightweight aerogels. By carefully modulating the nanofibrillation process, four types of NCFs could be readily fabricated, including long aggregated nanofiber bundles, long individualized nanofibers with surface C6 -carboxylate groups, short aggregated nanofibers, and short individualized nanofibers with surface sulfate groups. Free-standing lightweight aerogels were obtained from the corresponding aqueous NCF suspensions through freeze-drying. The structure of the aerogels could be controlled by manipulating the type of NCFs and the concentration of their suspensions. A possible mechanism for the self-aggregation of NCFs into two- or three-dimensional aerogel nanostructures was further proposed. Owing to web-like structure, high porosity, and high surface reactivity, the NCF aerogels exhibited high mechanical flexibility and ductility, and excellent properties for water uptake, removal of dye pollutants, and the use as thermal insulation materials. The aerogels also displayed sound-adsorption capability at high frequencies. PMID:24420495

  10. PROGRESS ON DCLL BLANKET CONCEPT C.P.C. Wonga

    E-print Network

    Abdou, Mohamed

    blanket design with a projected thermal efficiency of >40%. Reduced activation ferritic/martensitic (RAF for magnetohydrodynamic pressure drop reduction from the circulating liquid PbLi and as a thermal insulator to separate to provide electrical and thermal insulation between the breeder and structural material. In support

  11. US Plans and Strategy for ITER Blanket Testing

    E-print Network

    California at Los Angeles, University of

    -Cooled First Wall and Self-Cooled ­Pb-Li breeding zone with SiC INSERT for electrical/thermal insulation (all for the direction of activities in the US Chamber/Blanket Program: Provide fusion nuclear technology (FNT) support breeder concepts. Examples of issues are MHD insulators, MHD effects on heat transfer, tritium permeation

  12. Visible, near-infrared and infrared optical properties of silica aerogels

    NASA Astrophysics Data System (ADS)

    Fu, Tairan; Tang, Jiaqi; Chen, Kai; Zhang, Fan

    2015-07-01

    Silica aerogel is an excellent thermal insulation material with a low thermal conductivity and a high porosity and has attracted great concern in applications. This paper was to experimentally investigate the optical properties of optically thick silica aerogel in the visible, near-infrared and infrared spectrum region. The fiber-loaded silica aerogel sample was prepared through sol-gel technique and supercritical drying process. Silica fibers were added into the aerogel during the preparation procedure to strength the skeleton of aerogel. As a comparison with the fiber-load silica aerogel, a silica fiber composite sample with the same chemical component and different physical structure was also prepared. A simplified two-flux model neglecting the boundary effect was used to describe the radiation propagation characteristics inside the samples. The spectral normal-hemispherical reflectances, transmittances, and normal emittances of silica aerogel and silica fiber samples were measured and compared in the wavelengths of 0.38-15 ?m. Then the spectral optical constants of samples were determined using the experimental data. The spectral absorption and scattering coefficients of silica aerogel were within (0.01 cm-1, 31.0 cm-1) and (1.4 cm-1, 25.8 cm-1). The results showed that the spectrum region where the scattering coefficient is low usually corresponds to a high absorption coefficient. In addition, the total radiation properties of samples were predicted at high temperatures. The analysis of optical properties of silica aerogel is necessary to provide valuable data in applications.

  13. ITER convertible blanket evaluation

    SciTech Connect

    Wong, C.P.C.; Cheng, E.

    1995-09-01

    Proposed International Thermonuclear Experimental Reactor (ITER) convertible blankets were reviewed. Key design difficulties were identified. A new particle filter concept is introduced and key performance parameters estimated. Results show that this particle filter concept can satisfy all of the convertible blanket design requirements except the generic issue of Be blanket lifetime. If the convertible blanket is an acceptable approach for ITER operation, this particle filter option should be a strong candidate.

  14. Flexible Polyimide Aerogel Cross-linked by Poly(maleic Anhydride-alt-alkylene)

    NASA Technical Reports Server (NTRS)

    Guo, Haiquan; Meador, Mary Ann B.; Wilkewitz, Brittany Marie

    2014-01-01

    Aerogels are potential materials for aerospace applications due to their lower thermal conductivity, lighter weight, and low dielectric constant. However, silica aerogels are restricted due to their inherent fragility, hygroscopic nature, and poor mechanical properties, especially in extreme aerospace environments. In order to fit the needs of aerospace applications, developing new thermal insulation materials that are flexible, and moisture resistant is needed. To this end, we fabricated a series of polyimide aerogels crosslinked with different poly(maleic anhydride-alt-alkylene)s as seen in Scheme 1. The polyimide oligomers were made with 3,3,4,4-biphenyltetracarboxylic dianhydride (BPDA), and different diamines or diamine combinations. The resulting aerogels have low density (0.06 gcm3 to 0.16 gcm3) and high surface area (240-440 m2g). The effect of the different backbone structures on density, shrinkage, porosity, surface area, mechanical properties, moisture resistance and thermal properties will be discussed. These novel polyalkylene-imide aerogels may be potential candidates for applications such as space suit insulation for planetary surface missions, insulation for inflatable structures for habitats, inflatable aerodynamic decelerators for entry, descent and landing (EDL) operations, and cryotank insulation for advance space propulsion systems. Scheme 1. Network of polyimide aerogels crosslinked with deifferent poly(maleic anhydride).

  15. Materials for breeding blankets

    SciTech Connect

    Mattas, R.F.; Billone, M.C.

    1995-09-01

    There are several candidate concepts for tritium breeding blankets that make use of a number of special materials. These materials can be classified as Primary Blanket Materials, which have the greatest influence in determining the overall design and performance, and Secondary Blanket Materials, which have key functions in the operation of the blanket but are less important in establishing the overall design and performance. The issues associated with the blanket materials are specified and several examples of materials performance are given. Critical data needs are identified.

  16. Bonding aerogels with polyurethanes

    SciTech Connect

    Matthews, F.M.; Hoffman, D.M.

    1989-11-01

    Aerogels, porous silica glasses with ultra-fine cell size (30nm), are made by a solution gelation (sol-gel) process. The resulting gel is critical point dried to densities from 0.15--0.60 g/cc. This material is machinable, homogeneous, transparent, coatable and bondable. To bond aerogel an adhesive should have long cure time, no attack on the aerogel structure, and high strength. Several epoxies and urethanes were examined to determine if they satisfied these conditions. Bond strengths above 13 psi were found with double bubble and DP-110 epoxies and XI-208/ODA-1000 and Castall U-2630 urethanes. Hardman Kalex Tough Stuff'' A-85 hardness urethane gave 18 psi bond strength. Hardman A-85, Tuff-Stuff'' was selected for further evaluation because it produced bond strengths comparable to the adherend cohesive strength. 5 refs., 2 figs.

  17. Uncooled thin film pyroelectric IR detector with aerogel thermal isolation

    SciTech Connect

    Ruffner, J.A.; Bullington, J.A.; Clem, P.G.; Warren, W.L.; Brinker, C.J.; Tuttle, B.A.; Schwartz, R.W.

    1999-09-07

    A monolithic infrared detector structure which allows integration of pyroelectric thin films atop low thermal conductivity aerogel thin films is disclosed. The structure comprises, from bottom to top, a substrate, an aerogel insulating layer, a lower electrode, a pyroelectric layer, and an upper electrode layer capped by a blacking layer. The aerogel can offer thermal conductivity less than that of air, while providing a much stronger monolithic alternative to cantilevered or suspended air-gap structures for pyroelectric thin film pixel arrays. PbZr{sub 0.4}Ti{sub 0.6}O{sub 3} thin films deposited on these structures displayed viable pyroelectric properties, while processed at 550 C.

  18. Thermal properties of advanced aerogel insulation

    E-print Network

    Cohen, Ellann

    2011-01-01

    Buildings consume too much energy. For example, 16.6% of all the energy used in the United States goes towards just the heating and cooling of buildings. Many governments, organizations, and companies are setting very ...

  19. Leakage current and dielectric breakdown behavior in annealed SiO2 aerogel films

    Microsoft Academic Search

    Moon-Ho Jo; Hyung-Ho Park

    1998-01-01

    Leakage current and dielectric breakdown behavior in annealed SiO2 aerogel films for intermetal dielectric applications was investigated in a metal-insulator-semiconductor structure. SiO2 aerogel films with porosities of 70% exhibited Poole-Frenkel conduction both before and after annealing. After annealing at 450 and 700 °C, the leakage current density improved over the current range of the applied field. This behavior was characterized

  20. Polyvinyl alcohol-cellulose nanofibrils-graphene oxide hybrid organic aerogels.

    PubMed

    Javadi, Alireza; Zheng, Qifeng; Payen, Francois; Javadi, Abdolreza; Altin, Yasin; Cai, Zhiyong; Sabo, Ronald; Gong, Shaoqin

    2013-07-10

    Hybrid organic aerogels consisting of polyvinyl alcohol (PVA), cellulose nanofibrils (CNFs), and graphene oxide nanosheets (GONSs) were prepared using an environmentally friendly freeze-drying process. The material properties of these fabricated aerogels were measured and analyzed using various characterization techniques including compression testing, scanning electron microscopy, thermogravimetric (TGA) analysis, Brunauer-Emmet-Teller (BET) surface area analysis, and contact angle measurements. These environmentally friendly, biobased hybrid organic aerogels exhibited a series of desirable properties including a high specific compressive strength and compressive failure strain, ultralow density and thermal conductivity, good thermal stability, and moisture resistance, making them potentially useful for a broad range of applications including thermal insulation. PMID:23789837

  1. High power density self-cooled lithium-vanadium blanket.

    SciTech Connect

    Gohar, Y.; Majumdar, S.; Smith, D.

    1999-07-01

    A self-cooled lithium-vanadium blanket concept capable of operating with 2 MW/m{sup 2} surface heat flux and 10 MW/m{sup 2} neutron wall loading has been developed. The blanket has liquid lithium as the tritium breeder and the coolant to alleviate issues of coolant breeder compatibility and reactivity. Vanadium alloy (V-4Cr-4Ti) is used as the structural material because it can accommodate high heat loads. Also, it has good mechanical properties at high temperatures, high neutron fluence capability, low degradation under neutron irradiation, good compatibility with the blanket materials, low decay heat, low waste disposal rating, and adequate strength to accommodate the electromagnetic loads during plasma disruption events. Self-healing electrical insulator (CaO) is utilized to reduce the MHD pressure drop. A poloidal coolant flow with high velocity at the first wall is used to reduce the peak temperature of the vanadium structure and to accommodate high surface heat flux. The blanket has a simple blanket configuration and low coolant pressure to reduce the fabrication cost, to improve the blanket reliability, and to increase confidence in the blanket performance. Spectral shifter, moderator, and reflector are utilized to improve the blanket shielding capability and energy multiplication, and to reduce the radial blanket thickness. Natural lithium is used to avoid extra cost related to the lithium enrichment process.

  2. Silica aerogel production costs

    SciTech Connect

    Lewis, D.L.; Carlson, G.A.

    1993-01-01

    We performed a cost study for a silica aerogel production plant. It was found that the production costs are dominated by the cost of the base materials, and not by the energy (supercritical extraction) requirements. Alternative production methods using cheaper input materials (process development for TMOS, TEOS ) are needed.

  3. Silica aerogel production costs

    SciTech Connect

    Lewis, D.L.; Carlson, G.A.

    1993-01-01

    We performed a cost study for a silica aerogel production plant. It was found that the production costs are dominated by the cost of the base materials, and not by the energy (supercritical extraction) requirements. Alternative production methods using cheaper input materials (process development for TMOS, TEOS?) are needed.

  4. Characterization of Aerogel's Optical Properties

    NASA Astrophysics Data System (ADS)

    Justen, Abigail; Young, Jonathan

    2013-10-01

    Aerogel is used in the kaon aerogel Cerenkov detector at Jefferson Lab. Kaons are identified by the number of photons created through Cerenkov radiation emitted as the kaon travels through the aerogel. Depending on the refractive index of the aerogel, kaons of different momenta can be detected and distinguished from protons. Therefore, a uniform refractive index in the detector is important to reduce uncertainty in the Cerenkov radiation. We found the refractive index of the aerogel by shining a red construction laser through it and measuring how far the beam refracted. The refractive index of aerogel is also directly related to the density of aerogel. The humidity in the air, if absorbed, could also affect the refractive index. To test the effect of humidity on aerogel we used a humidity controlled environment between 80 and 100 percent on aerogel from Matsushita Electric Works, Ltd, Japan Fine Ceramic Center, and Novosibirsk. Finally, we tested the transmittance of aerogel tiles with a UV/Vis photospectrometer to find the correlation between transmittance and the tile's properties. Tiles with the highest transmittance will allow for the most accurate count of the photons produced through Cerenkov radiation. The results from these experiments will be presented. Supported in Part by NSF Grant 1019521 and 1039446.

  5. Surge current and electron swarm tunnel tests of thermal blanket and ground strap materials

    NASA Technical Reports Server (NTRS)

    Hoffmaster, D. K.; Inouye, G. T.; Sellen, J. M., Jr.

    1977-01-01

    The results are described of a series of current conduction tests with a thermal control blanket to which grounding straps have been attached. The material and the ground strap attachment procedure are described. The current conduction tests consisted of a surge current examination of the ground strap and a dilute flow, energetic electron deposition and transport through the bulk of the insulating film of this thermal blanket material. Both of these test procedures were used previously with thermal control blanket materials.

  6. Spectroscopic nanoporometry of aerogel

    NASA Astrophysics Data System (ADS)

    Petrova, T. M.; Ponomarev, Yu. N.; Solodov, A. A.; Solodov, A. M.; Danilyuk, A. F.

    2015-01-01

    The sizes of aerogel nanopores from the measured broadening of rotational-vibrational CO lines caused by collisions with nanopore walls have been determined. It has been shown that the sizes of nanopores with a diameter of 15-25 nm can be reliably assessed from the half-widths of spectral lines measured on a high-resolution Fourier spectrometer and agree well with the experimental data found from the low-temperature adsorption of nitrogen.

  7. Metal Nanoparticle Aerogel Composites

    NASA Technical Reports Server (NTRS)

    Smith, David D.; Sibille, Laurent; Ignont, Erica; Snow, Lanee; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    We have fabricated sol-gels containing gold and silver nanoparticles. Formation of an aerogel produces a blue shift in the surface plasmon resonance as a result of the decrease in the dielectric constant of the matrix upon supercritical extraction of the solvent. However, as a result of chemical interface damping this blue shift does not obey effective medium theories. Annealing the samples in a reducing atmosphere at 400 C eliminates this discrepancy and results in narrowing and further blue shifting of the plasmon resonance. Metal particle aggregation also results in a deviation from the predictions of effective medium theories, but can be controlled through careful handling and by avoiding the use of alcohol. By applying effective medium theories to the heterogeneous interlayer surrounding each metal particle, we extend the technique of immersion spectroscopy to inhomogeneous materials characterized by spatially dependent dielectric constants, such as aerogels. We demonstrate that the shift in the surface plasmon wavelength provides the average fractional composition of each component (air and silica) in this inhomogeneous layer, i.e. the porosity of the aerogel or equivalently, for these materials, the catalytic dispersion. Additionally, the kinetics suggest that collective particle interactions in coagulated metal clusters are perturbed during silica gelation resulting in a change in the aggregate geometry.

  8. Polymer material selection and testing of resistive wire arrangement for a transparent infant warming blanket

    E-print Network

    Salazar, Madeline

    2013-01-01

    The ThermoCloud was designed as a portable, scalable, transparent electrical blanket to warm and insulate infants, while permitting hassle-free medical transportation and maximum visualization of a patient's thorax and ...

  9. Method for producing metal oxide aerogels having densities less than 0. 02 g/cc

    DOEpatents

    Tillotson, T.M.; Poco, J.F.; Hrubesh, L.W.; Thomas, I.M.

    1994-01-04

    A two-step method is described for making transparent aerogels which have a density of less than 0.003 g/cm[sup 3] to those with a density of more than 0.8 g/cm[sup 3], by a sol/gel process and supercritical extraction. Condensed metal oxide intermediate made with purified reagents can be diluted to produce stable aerogels with a density of less than 0.02 g/cm[sup 3]. High temperature, direct supercritical extraction of the liquid phase of the gel produces hydrophobic aerogels which are stable at atmospheric moisture conditions. Monolithic, homogeneous silica aerogels with a density of less than 0.02 to higher than 0.8 g/cm[sup 3], with high thermal insulation capacity, improved mechanical strength and good optical transparency, are described. 7 figures.

  10. Organic carbon aerogels from the sol-gel polymerization of phenolic-furfural mixtures

    DOEpatents

    Pekala, R.W.

    1998-04-28

    The sol-gel polymerization of a phenolic-furfural mixture in dilute solution leads to a highly cross-linked network that can be supercritically dried to form a high surface area foam. These porous materials have cell/pore sizes {<=}1000 {angstrom}, and although they are dark brown in color, they can be classified as a new type of aerogel. The phenolic-furfural aerogel can be pyrolyzed in an inert atmosphere at 1050 C to produce carbon aerogels. This new aerogel may be used for thermal insulation, chromatographic packing, water filtration, ion-exchange, and carbon electrodes for energy storage devices, such as batteries and double-layer capacitors. 8 figs.

  11. Organic aerogels from the sol-gel polymerization of phenolic-furfural mixtures

    DOEpatents

    Pekala, Richard W. (Pleasant Hill, CA)

    1996-01-01

    The sol-gel polymerization of a phenolic-furfural mixture in dilute solution leads to a highly cross-linked network that can be supercritically dried to form a high surface area foam. These porous materials have cell/pore sizes .ltoreq.1000.ANG., and although they are dark brown in color, they can be classified as a new type of aerogel. The phenolic-furfural aerogel can be pyrolyzed in an inert atmosphere at 1050.degree. C. to produce carbon aerogels. This new aerogel may be used for thermal insulation, chromatographic packing, water filtration, ion-exchange, and carbon electrodes for energy storage devices, such as batteries and double-layer capacitors.

  12. Organic aerogels from the sol-gel polymerization of phenolic-furfural mixtures

    DOEpatents

    Pekala, Richard W. (Pleasant Hill, CA)

    1995-01-01

    The sol-gel polymerization of a phenolic-furfural mixture in dilute solution leads to a highly cross-linked network that can be supercritically dried to form a high surface area foam. These porous materials have cell/pore sizes.ltoreq.1000.ANG., and although they are dark brown in color, they can be classified as a new type of aerogel. The phenolic-furfural aerogel can be pyrolyzed in an inert atmosphere at 1050.degree. C. to produce carbon aerogels. This new aerogel may be used for thermal insulation, chromatographic packing, water filtration, ion-exchange, and carbon electrodes for energy storage devices, such as batteries and double-layer capacitors.

  13. Organic aerogels from the sol-gel polymerization of phenolic-furfural mixtures

    DOEpatents

    Pekala, R.W.

    1995-12-19

    The sol-gel polymerization of a phenolic-furfural mixture in dilute solution leads to a highly cross-linked network that can be supercritically dried to form a high surface area foam. These porous materials have cell/pore sizes{<=}1000{angstrom}, and although they are dark brown in color, they can be classified as a new type of aerogel. The phenolic-furfural aerogel can be pyrolyzed in an inert atmosphere at 1050 C to produce carbon aerogels. This new aerogel may be used for thermal insulation, chromatographic packing, water filtration, ion-exchange, and carbon electrodes for energy storage devices, such as batteries and double-layer capacitors. 8 figs.

  14. Organic aerogels from the sol-gel polymerization of phenolic-furfural mixtures

    DOEpatents

    Pekala, R.W.

    1996-09-17

    The sol-gel polymerization of a phenolic-furfural mixture in dilute solution leads to a highly cross-linked network that can be supercritically dried to form a high surface area foam. These porous materials have cell/pore sizes {<=}1,000{angstrom}, and although they are dark brown in color, they can be classified as a new type of aerogel. The phenolic-furfural aerogel can be pyrolyzed in an inert atmosphere at 1,050 C to produce carbon aerogels. This new aerogel may be used for thermal insulation, chromatographic packing, water filtration, ion-exchange, and carbon electrodes for energy storage devices, such as batteries and double-layer capacitors. 8 figs.

  15. Determining a Blanket Balance NUFinancials

    E-print Network

    Shull, Kenneth R.

    Determining a Blanket Balance NUFinancials Purchasing FMS815 Determining a Blanket Balance 10 to determine the remaining balance of a Blanket Purchase Order. Step 1: Access NUFinancials 1. Log the amount of the PO which has not been received. #12;Determining a Blanket Balance NUFinancials Purchasing

  16. MHD considerations for a self-cooled liquid lithium blanket

    SciTech Connect

    Sze, D.K.; Mattas, R.F.; Hull, A.B.; Picologlou, B.F.; Smith, D.L.

    1992-03-01

    The magnetohydrodynamic (MHD) effects can present a feasibility issue for a self-cooled liquid metal blanket of magnetically confined fusion reactors, especially inboard regime of a tokamak. This pressure drop can be significantly reduced by using insulated wall structure. A self-healing insulating coating has been identified, which will reduce the pressure drop by more than a factor of 10. The future research direction to further quantify the performance of this coating is also outlined.

  17. U.S. technical report for the ITER blanket/shield: A. blanket: Topical report, July 1990--November 1990

    SciTech Connect

    Not Available

    1995-01-01

    Three solid-breeder water-cooled blanket concepts have been developed for ITER based on a multilayer configuration. The primary difference among the concepts is in the fabricated form of breeder and multiplier. All the concepts have beryllium for neutron multiplication and solid-breeder temperature control. The blanket design does not use helium gaps or insulator material to control the solid breeder temperature. Lithium oxide (Li{sub 2}O) and lithium zirconate (Li{sub 2}ZrO{sub 3}) are the primary and the backup breeder materials, respectively. The lithium-6 enrichment is 95%. The use of high lithium-6 enrichment reduces the solid breeder volume required in the blanket and consequently the total tritium inventory in the solid breeder material. Also, it increases the blanket capability to accommodate power variation. The multilayer blanket configuration can accommodate up to a factor of two change in the neutron wall loading without violating the different design guidelines. The blanket material forms are sintered products and packed bed of small pebbles. The first concept has a sintered product material (blocks) for both the beryllium multiplier and the solid breeder. The second concept, the common ITER blanket, uses a packed bed breeder and beryllium blocks. The last concept is similar to the first except for the first and the last beryllium zones. Two small layers of beryllium pebbles are located behind the first wall and the back of the last beryllium zone to reduce the total inventory of the beryllium material and to improve the blanket performance. The design philosophy adopted for the blanket is to produce the necessary tritium required for the ITER operation and to operate at power reactor conditions as much as possible. Also, the reliability and the safety aspects of the blanket are enhanced by using low-pressure water coolant and the separation of the tritium purge flow from the coolant system by several barriers.

  18. Nanostructural engineering of organic aerogels

    SciTech Connect

    Pekala, R.W.; Alviso, C.T. [Lawrence Livermore National Lab., CA (United States); Lu, X.; Caps, R.; Frocle, J. [Physikalisches Institut der Universitat Wurzburg, Wurzburg, (Germany)

    1995-03-01

    Aerogels are a special class of open-cell foams with an ultrafine cell/pore size (<50 nm), high surface area (400-1100 M{sup 2}/g), and a solid matrix composed of interconnected colloidal-like particles or fibers with characteristic diameters of 10 nm. This paper examines the correlation between nanostructure and thermal conductivity in a series of resorcinol-formaldehyde (RF) aerogels prepared under different synthetic conditions.

  19. Reflecting layers reduce weight of insulation

    NASA Technical Reports Server (NTRS)

    Cole, J. D.; Schlessinger, E. D.; Rockoff, H. J.

    1981-01-01

    Metalized films placed between layers of fibrous material maintain equivalent thermal conductivity while cutting blanket density in half. Tests indicate that insulation with 1 lb/cu ft density with goldized films has thermal conductivity equal to 2 lb/cu ft of conventional insulation. Concept reduces weight in commercial aircraft and increases cargo space.

  20. Slotted Polyimide-Aerogel-Filled-Waveguide Arrays

    NASA Technical Reports Server (NTRS)

    Rodriguez-Solis, Rafael A.; Pacheco, Hector L.; Miranda, Felix A.; Meador, Mary Ann B.

    2013-01-01

    This presentation discussed the potential advantages of developing Slotted Waveguide Arrays using polyimide aerogels. Polyimide (PI) aerogels offer great promise as an enabling technology for lightweight aerospace antenna systems. PI aerogels are highly porous solids possessing low density and low dielectric permittivity combined with good mechanical properties. For slotted waveguide array applications, there are significant advantages in mass that more than compensate for the slightly higher loss of the aerogel filled waveguide when compared to state of practice commercial waveguide.

  1. Recent progress in silica aerogel Cherenkov radiator

    E-print Network

    Tabata, Makoto; Kawai, Hideyuki; Kubo, Masato; Sato, Takeshi

    2012-01-01

    In this paper, we present recent progress in the development of hydrophobic silica aerogel as a Cherenkov radiator. In addition to the conventional method, the recently developed pin-drying method for producing high-refractive-index aerogels with high transparency was studied in detail. Optical qualities and large tile handling for crack-free aerogels were investigated. Sufficient photons were detected from high-performance aerogels in a beam test.

  2. Composition containing aerogel substrate loaded with tritium

    SciTech Connect

    Ashley, Carol S. (Albuquerque, NM); Brinker, C. Jeffrey (Albuquerque, NM); Ellefson, Robert E. (Centerville, OH); Gill, John T. (Miamisburg, OH); Reed, Scott (Albuquerque, NM); Walko, Robert J. (Albuquerque, NM)

    1992-01-01

    The invention provides a process for loading an aerogel substrate with tritium and the resultant compositions. According to the process, an aerogel substrate is hydrolyzed so that surface OH groups are formed. The hydrolyzed aerogel is then subjected to tritium exchange employing, for example, a tritium-containing gas, whereby tritium atoms replace H atoms of surface OH groups. OH and/or CH groups of residual alcohol present in the aerogel may also undergo tritium exchange.

  3. Aerogel composites and method of manufacture

    DOEpatents

    Cao, Wanqing (Alameda, CA); Hunt, Arlon Jason (Oakland, CA)

    1999-01-01

    Disclosed herewith is a process of forming an aerogel composite which comprises introducing a gaseous material into a formed aerogel monolith or powder, and causing decomposition of said gaseous material in said aerogel in amounts sufficient to cause deposition of the decomposition products of the gas on the surfaces of the pores of the said aerogel. Also disclosed are the composites made by the process.

  4. Chitin and carbon aerogels from chitin alcogels

    Microsoft Academic Search

    Costas Tsioptsias; Chrysoula Michailof; George Stauropoulos; Costas Panayiotou

    2009-01-01

    Supercritical point drying of gels is a common technique for the production of a specific category of nano-porous materials called aerogels. We have successfully prepared chitin aerogels by extracting the solvent from the alcogels (gels with an alcohol as the solvent) with carbon dioxide under supercritical conditions. The produced nano-porous materials exhibit the typical properties of aerogels such as high

  5. Synergistic hybrid organic-inorganic aerogels.

    PubMed

    Wang, Xiao; Jana, Sadhan C

    2013-07-10

    A class of inorganic-organic hybrid mesoporous aerogel structure was synthesized by growing gel in a gel. In Type 1, silica gels were grown inside the macropores of thermoreversible syndiotactic polystyrene (sPS) gel, while Type 2 hybrid aerogels were obtained by thermoreversible gelation of sPS chains in the mesopores of preformed silica gel. The hybrid gels were converted into aerogels by exchanging the solvent with liquid carbon dioxide followed by supercritical drying. The hybrid aerogels presented cocontinuous networks of pearl-necklace silica particles and crystalline strands of sPS and exhibited the "petal effect" due to the presence of superhydrophobic sPS and hygroscopic silica. The compressive modulus and compressive strain show large enhancements over sPS and silica aerogels indicating synergy, although Type 1 hybrid aerogels were found to be more robust. The hybrid aerogels showed fast absorption and high absorption capacity for a representative hydrocarbon liquid. PMID:23773123

  6. Activity Summary: Determine a Blanket Balance

    E-print Network

    Shull, Kenneth R.

    Activity Summary: Determine a Blanket Balance NUFinancials Purchasing DetermineBlanketBalance This job aid describes how to determine the remaining balance of a Blanket purchase order. You can apply a Blanket Balance NUFinancials Purchasing DetermineBlanketBalance.doc Last Updated 3/7/2014 © 2014

  7. Biodegradable Pectin/clay Aerogels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biodegradable, foamlike materials based on renewable pectin and sodium montmorillonite clay were fabricated through a simple, environmentally friendly freeze-drying process. Addition of multivalent cations (Ca2+ and Al3+) resulted in apparent crosslinking of the polymer, and enhancement of aerogel p...

  8. Organically modified silicate aerogels, ``Aeromosils``

    SciTech Connect

    Kramer, S.J.; Mackenzie, J.D. [Univ. of California, Los Angeles, CA (United States). Dept. of Materials Science and Engineering; Rubio-Alonso, F. [CSIC, Madrid (Spain). Inst. de Ceramica y Vidrio

    1996-12-31

    Aerogels derived from sol-gel oxides such as silica have become quite scientifically popular because of their extremely low densities, high surface areas, and their interesting optical, dielectric, thermal and acoustic properties. However, their commercial applicability has thus far been rather limited, due in great part to their brittleness and hydrophilicity. In prior work by the research group, modifying silicate gel structures with flexible, organic containing polymers such as polydimethylsiloxane imparted significant compliance (even rubbery behavior) and hydrophobicity. These materials have been referred to as Ormosils. This study expounds on the current effort to extend these desirable properties to aerogels, and in-so-doing, creating novel ``Aeromosils``. Reactive incorporation of hydroxy-terminal polydimethylsiloxane (PDMS) into silica sol-gels was made using both acid and two-step acid/base catalyzed processes. Aerogels were derived by employing the supercritical CO{sub 2} technique. Analyses of microstructure were made using nitrogen adsorption (BET surface area and pore size distribution), and some mechanical strengths were derived from tensile strength testing. Interesting Aeromosil properties obtained include optical transparency, surface areas of up to 1,200 m{sup 2}/g, rubberiness, and better strength than corresponding silica aerogels with elongations at break exceeding 5% in some cases.

  9. Anisotropically structured magnetic aerogel monoliths

    NASA Astrophysics Data System (ADS)

    Heiligtag, Florian J.; Airaghi Leccardi, Marta J. I.; Erdem, Derya; Süess, Martin J.; Niederberger, Markus

    2014-10-01

    Texturing of magnetic ceramics and composites by aligning and fixing of colloidal particles in a magnetic field is a powerful strategy to induce anisotropic chemical, physical and especially mechanical properties into bulk materials. If porosity could be introduced, anisotropically structured magnetic materials would be the perfect supports for magnetic separations in biotechnology or for magnetic field-assisted chemical reactions. Aerogels, combining high porosity with nanoscale structural features, offer an exceptionally large surface area, but they are difficult to magnetically texture. Here we present the preparation of anatase-magnetite aerogel monoliths via the assembly of preformed nanocrystallites. Different approaches are proposed to produce macroscopic bodies with gradient-like magnetic segmentation or with strongly anisotropic magnetic texture.Texturing of magnetic ceramics and composites by aligning and fixing of colloidal particles in a magnetic field is a powerful strategy to induce anisotropic chemical, physical and especially mechanical properties into bulk materials. If porosity could be introduced, anisotropically structured magnetic materials would be the perfect supports for magnetic separations in biotechnology or for magnetic field-assisted chemical reactions. Aerogels, combining high porosity with nanoscale structural features, offer an exceptionally large surface area, but they are difficult to magnetically texture. Here we present the preparation of anatase-magnetite aerogel monoliths via the assembly of preformed nanocrystallites. Different approaches are proposed to produce macroscopic bodies with gradient-like magnetic segmentation or with strongly anisotropic magnetic texture. Electronic supplementary information (ESI) available: Digital photographs of dispersions and gels with different water-to-ethanol ratios; magnetic measurements of an anatase aerogel containing 0.25 mol% Fe3O4 nanoparticles; XRD patterns of the iron oxide and titania nanoparticles. See DOI: 10.1039/c4nr04694c

  10. Multipurpose hardened spacecraft insulation

    NASA Technical Reports Server (NTRS)

    Steimer, Carlos H.

    1990-01-01

    A Multipurpose Hardened Spacecraft Multilayer Insulation (MLI) system was developed and implemented to meet diverse survivability and performance requirements. Within the definition and confines of a MLI assembly (blanket), the design: (1) provides environmental protection from natural and induced nuclear, thermal, and electromagnetic radiation; (2) provides adequate electrostatic discharge protection for a geosynchronous satellite; (3) provides adequate shielding to meet radiated emission needs; and (4) will survive ascent differential pressure loads between enclosed volume and space. The MLI design is described which meets these requirements and design evolution and verification is discussed. The application is for MLI blankets which closeout the area between the laser crosslink subsystem (LCS) equipment and the DSP spacecraft cabin. Ancillary needs were implemented to ease installation at launch facility and to survive ascent acoustic and vibration loads. Directional venting accommodations were also incorporated to avoid contamination of LCS telescope, spacecraft sensors, and second surface mirrors (SSMs).

  11. Button cell supercapacitors with monolithic carbon aerogels

    NASA Astrophysics Data System (ADS)

    Pröbstle, H.; Schmitt, C.; Fricke, J.

    Carbon aerogels are highly porous materials prepared via pyrolysis of resorcinol-formaldehyde aerogels. The density of the aerogels can be varied in a wide range, whereby the major part of the pores is accessible to ionic conductors. Therefore, the application of high surface area aerogels as electrodes in supercapacitor devices is promising. In the present publication, the integration of thin monolithic aerogel composites in button cell casings is presented. The preparation of thin and mechanically stable aerogel electrodes was performed via integration of carbon fibers into the aerogel skeleton. In order to increase the external electrode area in the button cells (volume: 2.1 cm 3) a special folding technique for the electrodes (thickness: 180 ?m) was employed. The aerogel capacitors exhibit an excellent long term stability with no significant degradation after 80,000 charging and discharging cycles. According to a ragone-evaluation of the impedance data, the maximum power output and energy content for the aerogel button cells are 4.6 W and 4.9 mWh, respectively. The influence of CO 2-activation on the capacitive and resistive behavior of the electrodes in different aqueous electrolytes is analyzed using innovative analytical methods for cyclic voltammetry and impedance spectroscopy.

  12. Reduction of the Casimir force using aerogels

    E-print Network

    Esquivel-Sirvent, R

    2007-01-01

    By using silicon oxide based aerogels we show numerically that the Casimir force can be reduced several orders of magnitude, making its effect negligible in nanodevices. This decrease in the Casimir force is also present even when the aerogels are deposited on metallic substrates. To calculate the Casimir force we model the dielectric function of silicon oxide aerogels using an effective medium dielectric function such as the Clausius-Mossotti approximation. The results show that both the porosity of the aerogel and its thickness can be use as control parameters to reduce the magnitude of the Casimir force.

  13. The breeder blanket interface (BBI) to TSTA

    Microsoft Academic Search

    P. A. Finn; R. G. Clemmer; L. Greenwood; A. Lide; D. K. Sze; J. L. Anderson; R. Sherman; J. R. Bartlit; Y. Naruse; H. Yoshida

    1989-01-01

    A breeder blanket interface for an aqueous lithium salt blanket is defined for TSTA. High calculated radiolysis rates result in a high overpressure in the blanket and the need for a depressurizer and a recombiner system. High projected corrosion rates for stainless steel and for beryllium result in high activity levels in the blanket and the possible dissolution of the

  14. Fusion reactor blanket\\/shield design study

    Microsoft Academic Search

    D. L. Smith; R. G. Clemmer; S. D. Harkness; J. Jung; J. L. Krazinski; R. F. Mattas; H. C. Stevens; C. K. Youngdahl; C. Trachsel; D. Bowers

    1979-01-01

    A joint study of Tokamak reactor first wall\\/blanket\\/shield technology was conducted to identify key technological limitations for various tritium breeding blanket design concepts, establishment of a basis for assessment and comparison of the design features of each concept, and development of optimized blanket designs. The approach used involved a review of previously proposed blanket designs, analysis of critical technological problems

  15. Blanket technology experiments at Argonne National Laboratory

    Microsoft Academic Search

    R. F. Mattas; C. B. Reed; B. Picologlou; P. Finn; R. Clemmer; K. Porges; E. Bennett; L. R. Turner

    1988-01-01

    Argonne National Laboratory has the largest U.S. program for the development of blanket technology. The goals of the program are to resolve critical issues for different blanket concepts, to develop the understanding and predictive capability of blanket behavior, and to develop the technology needed to build and operate advanced fusion blankets. The projects within the program are liquid metal MHD,

  16. Blanket comparison and selection study. Volume II

    SciTech Connect

    Not Available

    1983-10-01

    This volume contains extensive data for the following chapters: (1) solid breeder tritium recovery, (2) solid breeder blanket designs, (3) alternate blanket concept screening, and (4) safety analysis. The following appendices are also included: (1) blanket design guidelines, (2) power conversion systems, (3) helium-cooled, vanadium alloy structure blanket design, (4) high wall loading study, and (5) molten salt safety studies. (MOW)

  17. Chemical Analyses of Silicon Aerogel Samples

    E-print Network

    van der Werf, I; De Leo, R; Marrone, S

    2008-01-01

    After five years of operating, two Aerogel counters: A1 and A2, taking data in Hall A at Jefferson Lab, suffered a loss of performance. In this note possible causes of degradation have been studied. In particular, various chemical and physical analyses have been carried out on several Aerogel tiles and on adhesive tape in order to reveal the presence of contaminants.

  18. Space environment durability of beta cloth in LDEF thermal blankets

    NASA Technical Reports Server (NTRS)

    Linton, Roger C.; Whitaker, Ann F.; Finckenor, Miria M.

    1993-01-01

    Beta cloth performance for use on long-term space vehicles such as Space Station Freedom (S.S. Freedom) requires resistance to the degrading effects of the space environment. The major issues are retention of thermal insulating properties through maintaining optical properties, preserving mechanical integrity, and generating minimal particulates for contamination-sensitive spacecraft surfaces and payloads. The longest in-flight test of beta cloth's durability was on the Long Duration Exposure Facility (LDEF), where it was exposed to the space environment for 68 months. The LDEF contained 57 experiments which further defined the space environment and its effects on spacecraft materials. It was deployed into low-Earth orbit (LEO) in Apr. 1984 and retrieved Jan. 1990 by the space shuttle. Among the 10,000 plus material constituents and samples onboard were thermal control blankets of multilayer insulation with a beta cloth outer cover and Velcro attachments. These blankets were exposed to hard vacuum, thermal cycling, charged particles, meteoroid/debris impacts, ultraviolet (UV) radiation, and atomic oxygen (AO). Of these space environmental exposure elements, AO appears to have had the greatest effect on the beta cloth. The beta cloth analyzed in this report came from the MSFC Experiment S1005 (Transverse Flat-Plate Heat Pipe) tray oriented approximately 22 deg from the leading edge vector of the LDEF satellite. The location of the tray on LDEF and the placement of the beta cloth thermal blankets are shown. The specific space environment exposure conditions for this material are listed.

  19. Solid phase microextraction device using aerogel

    DOEpatents

    Miller, Fred S.; Andresen, Brian D.

    2005-06-14

    A sample collection substrate of aerogel and/or xerogel materials bound to a support structure is used as a solid phase microextraction (SPME) device. The xerogels and aerogels may be organic or inorganic and doped with metals or other compounds to target specific chemical analytes. The support structure is typically formed of a glass fiber or a metal wire (stainless steel or kovar). The devices are made by applying gel solution to the support structures and drying the solution to form aerogel or xerogel. Aerogel particles may be attached to the wet layer before drying to increase sample collection surface area. These devices are robust, stable in fields of high radiation, and highly effective at collecting gas and liquid samples while maintaining superior mechanical and thermal stability during routine use. Aerogel SPME devices are advantageous for use in GC/MS analyses due to their lack of interfering background and tolerance of GC thermal cycling.

  20. Uncooled thin film infrared imaging device with aerogel thermal isolation: Deposition and planarization techniques

    SciTech Connect

    Ruffner, J.A.; Clem, P.G.; Tuttle, B.A.; Brinker, C.J. [Sandia National Labs., Albuquerque, NM (United States); Sriram, C.S. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Chemical and Nuclear Engineering; Bullington, J.A. [AMMPEC, Inc., Albuquerque, NM (United States)

    1998-04-01

    The authors have successfully integrated a thermally insulating silica aerogel thin film into a new uncooled monolithic thin film infrared (IR) imaging device. Compared to other technologies (bulk ceramic and microbridge), use of an aerogel layer provides superior thermal isolation of the pyroelectric imaging element from the relatively massive heat sinking integrated circuit. This results in significantly higher thermal and temporal resolutions. They have calculated noise equivalent temperature differences of 0.04--0.10 C from a variety of Pb{sub x}Zr{sub y}Ti{sub 1{minus}y}O{sub 3} (PZT) and Pb{sub x}La{sub 1{minus}x}Zr{sub y}Ti{sub 1{minus}y}O{sub 3} (PLZT) pyroelectric imaging elements in monolithic structures. In addition, use of aerogels results in an easier, less expensive fabrication process and a more robust device. Fabrication of these monolithic devices entails sol-gel deposition of the aerogel, sputter deposition of the electrodes, and solution chemistry deposition of the pyroelectric imaging elements. Uniform pyroelectric response is achieved across the device by use of appropriate planarization techniques. These deposition and planarization techniques are described. Characterization of the individual layers and monolithic structure using scanning electron microscopy, atomic force microscopy and Byer-Roundy techniques also is discussed.

  1. Uncooled thin film pyroelectric IR detector with aerogel thermal isolation

    SciTech Connect

    Ruffner, J.A.; Clem, P.G.; Tuttle, B.A. [and others

    1998-01-01

    Uncooled pyroelectric IR imaging systems, such as night vision goggles, offer important strategic advantages in battlefield scenarios and reconnaissance surveys. Until now, the current technology for fabricating these devices has been limited by low throughput and high cost which ultimately limit the availability of these sensor devices. We have developed and fabricated an alternative design for pyroelectric IR imaging sensors that utilizes a multilayered thin film deposition scheme to create a monolithic thin film imaging element on an active silicon substrate for the first time. This approach combines a thin film pyroelectric imaging element with a thermally insulating SiO{sub 2} aerogel thin film to produce a new type of uncooled IR sensor that offers significantly higher thermal, spatial, and temporal resolutions at a substantially lower cost per unit. This report describes the deposition, characterization and optimization of the aerogel thermal isolation layer and an appropriate pyroelectric imaging element. It also describes the overall integration of these components along with the appropriate planarization, etch stop, adhesion, electrode, and blacking agent thin film layers into a monolithic structure. 19 refs., 8 figs., 6 tabs.

  2. Aerogel Projects Ongoing in MSFC's Engineering Directorate

    NASA Technical Reports Server (NTRS)

    Shular, David A.; Smithers, Gweneth A.; Plawsky, Joel L.; Whitaker, Ann F. (Technical Monitor)

    2000-01-01

    When we speak of an aerogel material, we are referring more to process and structure am to a specific substance. Aerogel, considered the lightest solid material, has been made from silica for seventy years. Resorcinol-formaldehyde, organic aerogels have been developed more recently. However, aerogel can be made from almost any type of substance, even lead. Because an aerogel is mostly air (about 99 %), the solid substance used will affect the weight very little. The term "aerogel" connotes the sol-gel process used to manufacture the material. The aerogel begins as a liquid "sol," becomes a solid "alcogel," and is then dried to become an "aerogel." The final product has a unique structure, useful for exploitation. It is an "open pore" system with nano-sized particles and pores, has very high surface area, and is highly interconnected. Besides low weight, aerogels have ultimate (lowest) values in other properties: thermal conductivity, refractive index, sound speed, and dielectric constant. Aerogels were first prepared in 1931 by Steven Kistler, who used a supercritical drying step to replace the liquid in a gel with air, preserving the structure (1). Kistler's procedure involved a water-to-alcohol exchange step; in the 1970's, this step was eliminated when a French investigator introduced the use of tetramethylorthosilicate. Still, alcohol drying involved dangerously high temperatures and pressures. In the 1980's, the Microstructured Materials Group at Berkeley Laboratory found that the alcohol in the gel could be replaced with liquid carbon dioxide before supercritical drying, which greatly improved safety (2). 'Me most recent major contribution has been that of Deshpande, Smith and Brinker in New Mexico, who are working to eliminate the supercritical drying step (3). When aerogels were first being developed, they were evaporatively dried. However, the wet gel, when dried, underwent severe shrinkage and cracking; this product was termed "xerogel." When the autoclave drying step was introduced, the final product was without cracks and showed only minimal shrinkage; this product was termed "aerogel." In the 1990's, Deshpande, Smith and Brinker developed an evaporative drying procedure in which the wet gel is chemically "capped" so that the material, which undergoes shrinkage, springs back to its original size when evaporatively dried. This new type of xerogel, while uncracked and almost the same size as the wet gel, differs from the autoclave-dried product in that it is less porous (approximately 70%, as compared to 99% for aerogels).

  3. Chemistry in an inorganic-organic hybrid aerogel: Chitosan-silica aerogel

    NASA Astrophysics Data System (ADS)

    Liu, Xipeng

    2005-11-01

    In this thesis, chemistry in a nanoporous inorganic-organic hybrid aerogel (X-silica aerogel) has been explored. The aerogel typically consisted of 10%w/w bioderived polymer (chitosan), and 90%w/w inorganic silica, which interact at the molecule level. The aerogel has a low density in the range of 0.2--0.3 g/cm3, high surface area in the range of 500--950m 2/g, and large pore volume about 90%. The pores are about 3--5 nm in diameter and the size of the primary particles comprising the aerogel network is about 1.5nm. Chemical studies of X-silica aerogels were carried out in the first instance with organic molecules, including dansyl chloride (DC), succinic anhydride (SA), bis(4-isocynatocyclohexyl) methane (HMDI), and isocyanatoethyl methacrylate (IEMA). These reactions lead to modified X-silica aerogel products imparted with valuable functionalities, including fluorescence, carboxylic acid groups, and pendant isocyanate and methacrylate groups. The functionalized aerogels then were utilized to form novel composites. The isocyanate functionalized aerogels were combined with amine-containing silicone polymers to produce aerogel-silicone polymer composites, and methacrylate functionalized aerogels were reacted with hydroxyethylmethacrylate (HEMA) monomer to produce aerogel-polyHEMA composites. The chemical studies were extended to gold-ion Au(III)-X-silica aerogels. Photoreduction of the Au(IIl)-X-silica aerogels by UV irradiation at 254nm reduced the Au(III) ions into Au(0) nanoparticles (AuNPs) while oxidizing the chitosan. Various sizes of AuNPs, with mean diameters from 8--87nm were obtained by varying the Au(III) ions concentration in aerogels from Au(III)/-NH 2 (-NH2 amine groups on chitosan) ratio 1:120 to 1:5. The intensity and time of exposure to the UV light were varied to explore their effect. Two dimensional patterns of Au(0)-X-silica aerogels were achieved by UV irradiation through a mask. Photo-reduction of Au(III)-X-silica aerogels in the presence of various thiols and disulfides leads to functionalized Au nanoparticles by the strong chemisorption of sulfurs and Au nanoparticles. Moreover, when these are present during the photolysis they control the growth of the gold nanoparticles.

  4. Radon adsorption on an aerogel

    NASA Astrophysics Data System (ADS)

    Schopfer, Carl J.

    Radon is an important radioactive gas, responsible for environmental exposures and subsequent impact on human health. It is a Noble gas and under most circumstances is not chemically reactive. Its physical properties and resultant behavior, however, may not be simple in all cases, especially where barriers to free diffusion are present, or when encountering materials with special properties. The importance of radon comes from its radioactivity, by imparting energy in material after decay, with resulting damage to living tissue. Transport in the environment is controlled by its physical properties, since it is chemically inert. Aerogels made of silica glass are a relatively new material with the unique property of having a very large surface area, on the order of hundreds of m2 per gram, compared to the exterior surface of the bulk volume of typical solid materials. Insight may be gained into the behavior of both radon and unique materials by observing how radon interacts with such materials. Silica aerogel monoliths with bulk densities of approximately 0.25 g cm-3 were manufactured and exposed to radon gas diffusing freely into the gel using a closed chamber. Measurements were taken while allowing the gas to diffuse out of the gel. Radon is found to diffuse out of the sample chamber at about the same rate when a gel material is present as from an empty chamber. Long-term measurements show radioactivity (from progeny) remains present leading to the conclusion that, the radon may have penetrated some distance into the gel. This leaves open the possibility of applying aerogels as a radon detector. The aerogel manufactured in this study did not preferentially absorb radon. Some evidence suggests that radon may have penetrated the surface however, based on increased long-term radioactivity. Doping the gel with cerium salts, known to cause glass produced by melting processes to scintillate when exposed to ionizing radiation did not produce observable light signal distinguishable from Cerenkov radiation, thereby excluding the hypothesis that the cerium will scintillate in the current arrangement.

  5. Affordable Window Insulation with R-10/inch Rating

    SciTech Connect

    Jenifer Marchesi Redouane Begag; Je Kyun Lee; Danny Ou; Jong Ho Sonn; George Gould; Wendell Rhine

    2004-10-15

    During the performance of contract DE-FC26-00-NT40998, entitled ''Affordable Window Insulation with R-10/inch Value'', research was conducted at Aspen Aerogels, Inc. to develop new transparent aerogel materials suitable for window insulation applications. The project requirements were to develop a formulation or multiple formulations that have high transparency (85-90%) in the visible region, are hydrophobic (will not opacify with exposure to water vapor or liquid), and have at least 2% resiliency (interpreted as recoverable 2% strain and better than 5% strain to failure in compression). Results from an unrelated project showed that silica aerogels covalently bonded to organic polymers exhibit excellent mechanical properties. At the outset of this project, we believed that such a route is the best to improve mechanical properties. We have applied Design of Experiment (DOE) techniques to optimize formulations including both silica aerogels and organically modified silica aerogels (''Ormosils''). We used these DOE results to optimize formulations around the local/global optimization points. This report documents that we succeeded in developing a number of formulations that meet all of the stated criteria. We successfully developed formulations utilizing a two-step approach where the first step involves acid catalyzed hydrolysis and the second step involves base catalyzed condensation to make the gels. The gels were dried using supercritical CO{sub 2} and we were able to make 1 foot x 1 foot x 0.5 inch panels that met the criteria established.

  6. Facile preparation of monolithic ?-carrageenan aerogels.

    PubMed

    Ganesan, Kathirvel; Ratke, Lorenz

    2014-05-14

    To the best of our knowledge, it is the first study reporting the synthesis of monolithic ?-carrageenan aerogels with meso- and macroporous structures, being unique in physical and chemical properties. We demonstrate a novel method to synthesize ?-carrageenan aerogels in which potassium thiocyanate was used as the source of specific ions. Aerogels were characterized by envelope density analysis, scanning electron microscopy, nitrogen adsorption-desorption analysis, X-ray powder diffractometry and IR spectroscopy. By varying the concentration of ?-carrageenan between 0.5 and 3 wt%, the envelope density can be linearly increased from 40 to 160 kg m?³. The sulphate functional groups in the wet gel and the specific ions are the key factors controlling the volume shrinkage of aerogels which average about 66%. The aerogels exhibit a fibrillar structure similar to cellulose aerogels. The fibril thickness was observed to be 10-15 nm and the specific surface area was about 230 m² g?¹. The existing meso- and macroporous structures were confirmed by nitrogen adsorption-desorption isotherm analysis and scanning electron microscopy. The aerogels were completely pure, free of specific ions and confirmed to be amorphous by powder X-ray diffraction. Hence, these porous materials can provide a matrix with a chelating function which can be used as a host in many applications. PMID:24718695

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

    NASA Technical Reports Server (NTRS)

    Sullivan, Thomas A. (Inventor)

    2007-01-01

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

  8. Measurement of muonium emission from silica aerogel

    E-print Network

    Bakule, P; Contreras, D; Esashi, M; Fujiwara, Y; Fukao, Y; Hirota, S; Iinuma, H; Ishida, K; Iwasaki, M; Kakurai, T; Kanda, S; Kawai, H; Kawamura, N; Marshall, G M; Masuda, H; Matsuda, Y; Mibe, T; Miyake, Y; Okada, S; Olchanski, K; Olin, A; Onishi, H; Saito, N; Shimomura, K; Strasser, P; Tabata, M; Tomono, D; Ueno, K; Yokoyama, K; Yoshida, S

    2013-01-01

    Emission of muonium ($\\mu^{+}e^{-}$) atoms from silica aerogel into vacuum was observed. Characteristics of muonium emission were established from silica aerogel samples with densities in the range from 29 mg cm$^{-3}$ to 178 mg cm$^{-3}$. Spectra of muonium decay times correlated with distances from the aerogel surfaces, which are sensitive to the speed distributions, follow general features expected from a diffusion process, while small deviations from a simple room-temperature thermal diffusion model are identified. The parameters of the diffusion process are deduced from the observed yields.

  9. Band Formation during Gaseous Diffusion in Aerogels

    E-print Network

    M. A. Einarsrud; F. A. Maao; A. Hansen; M. Kirkedelen; J. Samseth

    1997-06-18

    We study experimentally how gaseous HCl and NH_3 diffuse from opposite sides of and react in silica aerogel rods with porosity of 92 % and average pore size of about 50 nm. The reaction leads to solid NH_4Cl, which is deposited in thin sheet-like structures. We present a numerical study of the phenomenon. Due to the difference in boundary conditions between this system and those usually studied, we find the sheet-like structures in the aerogel to differ significantly from older studies. The influence of random nucleation centers and inhomogeneities in the aerogel is studied numerically.

  10. Hydrophobic silica aerogel production at KEK

    E-print Network

    Tabata, Makoto; Kawai, Hideyuki; Sumiyoshi, Takayuki; Yokogawa, Hiroshi

    2011-01-01

    We present herein a characterization of a standard method used at the High Energy Accelerator Research Organization (KEK) to produce hydrophobic silica aerogels and expand this method to obtain a wide range of refractive index (n = 1.006-1.14). We describe in detail the entire production process and explain the methods used to measure the characteristic parameters of aerogels, namely the refractive index, transmittance, and density. We use a small-angle X-ray scattering (SAXS) technique to relate the transparency to the fine structure of aerogels.

  11. Low density, resorcinol-formaldehyde aerogels

    DOEpatents

    Pekala, Richard W. (Pleasant Hill, CA)

    1989-01-01

    The polycondensation of resorcinol with formaldehyde under alkaline conditions results in the formation of surface functionalized polymer "clusters". The covalent crosslinking of these "clusters" produces gels which when processed under supercritical conditions, produce low density, organic aerogels (density .ltoreq.100 mg/cc; cell size .ltoreq.0.1 microns). The aerogels are transparent, dark red in color and consist of interconnected colloidal-like particles with diameters of about 100 .ANG.. These aerogels may be further carbonized to form low density carbon foams with cell size of about 0.1 micron.

  12. Low density, resorcinol-formaldehyde aerogels

    DOEpatents

    Pekala, Richard W. (Pleasant Hill, CA)

    1991-01-01

    The polycondensation of resorcinol with formaldehyde under alkaline conditions results in the formation of surface functionalized polymer "Clusters". The covalent crosslinking of these "clusters" produces gels which when processed under supercritical conditions, produce low density, organic aerogels (density.ltoreq.100 mg/cc; cell size .ltoreq.0.1 microns). The aerogels are transparent, dark red in color and consist of interconnected colloidal-like particles with diameters of about 100.circle.. These aerogels may be further carbonized to form low density carbon foams with cell size of about 0.1 micron.

  13. Low density, resorcinol-formaldehyde aerogels

    DOEpatents

    Pekala, R.W.

    1989-10-10

    The polycondensation of resorcinol with formaldehyde under alkaline conditions results in the formation of surface functionalized polymer clusters. The covalent crosslinking of these clusters produces gels which when processed under supercritical conditions, produce low density, organic aerogels (density [<=]100 mg/cc; cell size [<=]0.1 microns). The aerogels are transparent, dark red in color and consist of interconnected colloidal-like particles with diameters of about 100 [angstrom]. These aerogels may be further carbonized to form low density carbon foams with cell size of about 0.1 micron.

  14. Low density, resorcinol-formaldehyde aerogels

    DOEpatents

    Pekala, R.W.

    1988-05-26

    The polycondensation of resorcinol with formaldehyde under alkaline conditions results in the formation of surface functionalized polymer ''clusters''. The covalent crosslinking of these ''clusters'' produces gels which when processed under supercritical conditions, produce low density, organic aerogels (density less than or equal to100 mg/cc; cell size less than or equal to0.1 microns). The aerogels are transparent,dark red in color and consist of interconnected colloidal-like particles with diameters of about 100 A/degree/. These aerogels may be further carbonized to form low density carbon foams with cell size of about 0.1 micron. 1 fig., 1 tab.

  15. High-Tech, Low-Temp Insulation

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Under an SBIR (Small Business Innovative Research) contract with Ames, S.D. Miller & Associates developed new manufacturing methods for multi-layer metal spacecraft insulation that could significantly reduce launch weight and launch costs. The new honeycomb structure is more efficient than fibers for insulation. Honeycombs can be made from metals for high temperature uses, even plastic insulation from recycled milk bottles. Under development are blankets made from recycled milk bottles which will be field tested by the Red Cross and ambulance companies. Currently available are honeycomb mittens based on the same technology.

  16. Thermal conductivity of thermal-battery insulations

    SciTech Connect

    Guidotti, R.A.; Moss, M.

    1995-08-01

    The thermal conductivities of a variety of insulating materials used in thermal batteries were measured in atmospheres of argon and helium using several techniques. (Helium was used to simulate the hydrogen atmosphere that results when a Li(Si)/FeS{sub 2} thermal battery ages.) The guarded-hot-plate method was used with the Min-K insulation because of its extremely low thermal conductivity. For comparison purposes, the thermal conductivity of the Min-K insulating board was also measured using the hot-probe method. The thermal-comparator method was used for the rigid Fiberfrax board and Fiberfrax paper. The thermal conductivity of the paper was measured under several levels of compression to simulate the conditions of the insulating wrap used on the stack in a thermal battery. The results of preliminary thermal-characterization tests with several silica aerogel materials are also presented.

  17. The blanket interface to TSTA

    SciTech Connect

    Clemmer, R.G.; Finn, P.A.; Grimm, T.L.; Sze, D.K.; Anderson, J.L.; Bartlit, J.R.; Naruse, Y.; Yoshida, H.

    1988-09-01

    The requirements of tritium technology are centered in three main areas, (1) fuel processing, (2) breeder tritium extraction, and (3) tritium containment. The Tritium Systems Test Assembly (TSTA) now in operation at Los Alamos National Laboratory (LANL) is dedicated to developing and demonstrating the tritium technology for fuel processing and containment. TSTA is the only fusion fuel processing facility that can operate in a continuous closed-loop mode. The tritium throughput of TSTA is 1000 g/d. However, TSTA does not have a blanket interface system. The authors have initiated a study to define a Breeder Blanket Interface (BBIO) for TSTA. The first step of the work is to define the condition of the gaseous tritium stream from the blanket tritium recovery system. This report summarizes this part of the work for one particular blanket concept, i.e., a self-cooled lithium blanket. The total gas throughput, the hydrogen to tritium ratio, the corrosive chemicals, and the radionuclides are defined. Various methods of tritium recovery from liquid lithium were assessed: yttrium gettering, permeation windows, and molten salt extraction. The authors' evaluation concluded that the best method was molten salt extraction.

  18. Silica Aerogel Captures Cosmic Dust Intact

    NASA Technical Reports Server (NTRS)

    Tsou, P.

    1994-01-01

    The mesostructure of silica aerogel resembles stings of grapes, ranging in size from 10 to 100 angstrom. This fine mesostructure transmits nearly 90 percent of incident light in the visible, while providing sufficiently gentle dissipation of the kinetric energy of hypervelocity cosmic dust particles to permit their intact capture. We introduced silica aerogel in 1987 as capture medium to take advantage of its low density, fine mesostruicture and most importantly, its transparency, allowing optical location of captured micron sized particles.

  19. Method for making monolithic metal oxide aerogels

    DOEpatents

    Droege, M.W.; Coronado, P.R.; Hair, L.M.

    1995-03-07

    Transparent, monolithic metal oxide aerogels of varying densities are produced using a method in which a metal alkoxide solution and a catalyst solution are prepared separately and reacted. The resulting hydrolyzed-condensed colloidal solution is gelled, and the wet gel is contained within a sealed, but gas permeable, containment vessel during supercritical extraction of the solvent. The present invention is especially advantageous for making metal oxides other than silica that are prone to forming opaque, cracked aerogels. 6 figs.

  20. Method for making monolithic metal oxide aerogels

    DOEpatents

    Droege, Michael W. (Livermore, CA); Coronado, Paul R. (Livermore, CA); Hair, Lucy M. (Livermore, CA)

    1995-01-01

    Transparent, monolithic metal oxide aerogels of varying densities are produced using a method in which a metal alkoxide solution and a catalyst solution are prepared separately and reacted. The resulting hydrolyzed-condensed colloidal solution is gelled, and the wet gel is contained within a sealed, but gas permeable, containment vessel during supercritical extraction of the solvent. The present invention is especially advantageous for making metal oxides other than silica that are prone to forming opaque, cracked aerogels.

  1. Single-wall carbon nanotube aerogels

    NASA Astrophysics Data System (ADS)

    Bryning, M. B.; Islam, M. F.; Hough, L. A.; Yodh, A. G.

    2006-03-01

    Aerogels of single-wall carbon nanotubes (SWNTs) were created by freeze drying and critical point drying of aqueous SWNT gels. The resulting aerogels maintain the strongly-connected three-dimensional SWNT network of the original gel and have density less than 0.1 g/cm3. While these pure SWNT aerogels are self-supporting, reinforcement with small amounts of added polyvinylalcohol (PVA) produces much stronger structures that are easy to handle. Electrical conductivity of order 1 S/cm is observed in the self-supporting aerogels, and similar conductivity can be achieved in PVA-reinforced aerogels through additional processing. The aerogels can be backfilled with polymers such as epoxy to create composite materials that retain the high conductivity of the network. Other potential applications for these structures, such as sensors, actuators, and thermoelectric devices, are currently being explored. This work is supported by grants from NSF (MRSEC DMR05-20020 and DMR-0505048) and NASA NAG8-2172.

  2. 47 CFR 73.88 - Blanketing interference.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Blanketing interference. 73.88 Section 73.88 Telecommunication...Broadcast Stations § 73.88 Blanketing interference. The licensee of each broadcast...reasonable complaints of blanketing interference within the 1 V/m contour....

  3. 47 CFR 73.88 - Blanketing interference.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Blanketing interference. 73.88 Section 73.88 Telecommunication...Broadcast Stations § 73.88 Blanketing interference. The licensee of each broadcast...reasonable complaints of blanketing interference within the 1 V/m contour....

  4. 47 CFR 73.88 - Blanketing interference.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Blanketing interference. 73.88 Section 73.88 Telecommunication...Broadcast Stations § 73.88 Blanketing interference. The licensee of each broadcast...reasonable complaints of blanketing interference within the 1 V/m contour....

  5. 47 CFR 73.88 - Blanketing interference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 false Blanketing interference. 73.88 Section 73.88 Telecommunication...Broadcast Stations § 73.88 Blanketing interference. The licensee of each broadcast...reasonable complaints of blanketing interference within the 1 V/m contour....

  6. 47 CFR 73.88 - Blanketing interference.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 false Blanketing interference. 73.88 Section 73.88 Telecommunication...Broadcast Stations § 73.88 Blanketing interference. The licensee of each broadcast...reasonable complaints of blanketing interference within the 1 V/m contour....

  7. Durable polymer-aerogel based superhydrophobic coatings, a composite material

    DOEpatents

    Kissel, David J; Brinker, Charles Jeffrey

    2014-03-04

    Provided are polymer-aerogel composite coatings, devices and articles including polymer-aerogel composite coatings, and methods for preparing the polymer-aerogel composite. The exemplary article can include a surface, wherein the surface includes at least one region and a polymer-aerogel composite coating disposed over the at least one region, wherein the polymer-aerogel composite coating has a water contact angle of at least about 140.degree. and a contact angle hysteresis of less than about 1.degree.. The polymer-aerogel composite coating can include a polymer and an ultra high water content catalyzed polysilicate aerogel, the polysilicate aerogel including a three dimensional network of silica particles having surface functional groups derivatized with a silylating agent and a plurality of pores.

  8. Synthesis and characterization of a nanocrystalline diamond aerogel

    SciTech Connect

    Pauzauskie, Peter J.; Crowhurst, Jonathan C.; Worsley, Marcus A.; Laurence, Ted A.; Kilcoyne, A. L. David; Wang, Yinmin; Willey, Trevor M.; Visbeck, Kenneth S.; Fakra, Sirine C.; Evans, William J.; Zaug, Joseph M.; Satcher, Jr., Joe H.

    2011-07-06

    Aerogel materials have myriad scientific and technological applications due to their large intrinsic surface areas and ultralow densities. However, creating a nanodiamond aerogel matrix has remained an outstanding and intriguing challenge. Here we report the high-pressure, high-temperature synthesis of a diamond aerogel from an amorphous carbon aerogel precursor using a laser-heated diamond anvil cell. Neon is used as a chemically inert, near-hydrostatic pressure medium that prevents collapse of the aerogel under pressure by conformally filling the aerogel's void volume. Electron and X-ray spectromicroscopy confirm the aerogel morphology and composition of the nanodiamond matrix. Time-resolved photoluminescence measurements of recovered material reveal the formation of both nitrogen- and silicon- vacancy point-defects, suggesting a broad range of applications for this nanocrystalline diamond aerogel.

  9. The scaling laws of a cold gas-blanket experiment

    NASA Astrophysics Data System (ADS)

    Kuthy, A.

    Experimental investigations of a cold gas-blanket surrounding a fully ionized plasma core have been performed. The gas blanket is produced in the F-1 rotating plasma device having a purely poloidal magnetic field, B?0.5 T, major radius R = 0.3 m, electron density in the range of 10 21 m -3, electron temperature T = 5 eV and rotation velocity ?? = 10 5 m/s. It is found that the transverse particle diffusion is classical and the scaling of the plasma density, nb, with the neutral hydrogen density at the wall, n1w, follows the law n b ? (n 1 wB 2) {1}/{3} agreeing with theory based on the momentum and particle balances. The scaling of the temperature with the power input cannot be accounted for on the basis of the transverse heat-balance alone. The thickness of the boundary layer decreases with increasing power input, but the maximum power input compatible with a gas-blanket could not be determined due to the Alfvén critical-velocity effect, which limited the rotation velocity at the insulator surfaces. The minimum power input needed to maintain an impermeable plasma core was found to be 0.25 MW.

  10. Aerogels: A new material for emissive display applications

    SciTech Connect

    Glauser, S.A.C. [California Univ., Davis, CA (United States); Lee, H.W.H. [Lawrence Livermore National Lab., CA (United States)

    1997-03-01

    The remarkable optical and electronic properties of doped and undoped silica aerogels establish their utility as unique, multifunctional host materials for fluorescent dyes and other luminescent materials for display and imaging applications. We present results on the photoluminescence and absorption of undoped silica aerogels and aerogels doped with Er{sup 3+}, rhodamine 6G (R6G), and fluorescein. We also demonstrate evidence of Fowler-Nordheim tunneling of electrons in aerogels. 4 refs., 10 figs.

  11. Carbon aerogels: An update on structure, properties, and applications

    SciTech Connect

    Pekala, R.W.; Mayer, S.T.; Kaschmitter, J.L.; Kong, F.M.

    1993-07-01

    Aerogels are unique porous materials whose composition, structure, and properties can be controlled at the nanometer scale. This paper examines the synthesis of organic aerogels and their carbonized derivatives. Carbon aerogels have low electrical resistivity, high surface area, and a tunable pore size. These materials are finding applications as electrodes in double layer capacitors.

  12. Silica aerogel: An intrinsically low dielectric constant material

    Microsoft Academic Search

    Hrubesh

    1995-01-01

    Silica aerogels are highly porous solids having unique morphologies in wavelength of visible which both the pores and particles have sizes less than the wavelength of visible light. This fine nanostructure modifies the normal transport mechanisms within aerogels and endows them with a variety of exceptional physical properties. For example, aerogels have the lowest measured thermal conductivity and dielectric constant

  13. Extraction of Particles Impacted into Silica Aerogel

    NASA Astrophysics Data System (ADS)

    Graham, G. A.; Chater, R. J.; Kearsley, A. T.; Burchell, M. J.; Bradley, J. P.

    2003-04-01

    The capture of intact cosmic dust grains, wherein both volatile chemical components and the mineral stoichiometry have survived, has proven difficult to achieve. However, development of low-density silica aerogel capture cells has been stimulated by the preparation for the NASA Stardust mission. To see what material this mission has collected, the research community must wait until 2006 for the return of the spacecraft, currently en route to Comet Wild 2. This interim period between launch and sample return should be used to assess the capabilities and difficulties of aerogel use, with low Earth orbit (LEO) flight opportunities and the development of extraction and analysis protocols in the laboratory. The ground-based studies are particularly important as LEO opportunities are limited, the last space-flown aerogel capture cell was on the now de-orbited MIR space station. Despite the paucity of orbital data, it is possible to simulate the expected cometary encounter velocities of the Stardust collectors using light-gas-gun and Van de Graaff particle accelerators. We have carried out a series of hypervelocity impact experiments using aerogel targets, with a variety of aerogel densities and compositions. A range of projectiles were used, from simple single homogeneous minerals (e.g. olivine) to complex crushed heterogeneous meteorite powders. The impacted targets were subjected to preliminary characterisation using optical and Raman microscopy, to assess location, composition and mineralogy of the captured grains. We have previously reported successful extraction of individual grains, and tracks containing fragments, by use of a UV laser system (COSPAR, 2002). During the impact between the projectile and the aerogel target, a thin layer of denatured aerogel is deposited on the grain, our preliminary experiments have shown that this aerogel coating can be removed from the grain surface by use of in-situ focused ion beam (FIB) techniques. We are now developing the application of FIB microscopy to further assist particle extraction. It is possible to ion-mill precise volumes of aerogel at controlled rates, whilst acquiring both secondary electron and ion images to monitor the milling progress. We believe that it is now timely to refine these techniques, particularly those relating to extraction, so they can be applied confidently and routinely to this unique and yet challenging capture medium.

  14. High resolution transmission electron microscopy of melamine-formaldehyde aerogels and silica aerogels

    SciTech Connect

    Ruben, G.C. (Dartmouth Coll., Hanover, NH (United States). Dept. of Biological Sciences)

    1991-09-01

    The goal of the high resolution transmission electron microscopy (HRTEM) was to image the structure of two tetramethyl orthosilicate (TMOS) and two melamine-formaldehyde (MF) aerogels at the single polymer chain level{sup 1,2}. With this level of structural resolution we hoped to interrelate each aerogel's structure with its physical properties and its method of synthesis. Conventional single-step base catalysed TMOS aerogels show strings of spheroidal particles linked together with minimal necking. The spheroidal particles range from 86--132 {Angstrom} and average 113{plus minus}10 {Angstrom} in diameter{sup 2}. In contrast the TMOS aerogels reported on here were made by a two step method. After extended silica chains are grown in solution under acidic conditions with a substoichiometric amount of water, the reaction is stopped and the methanol hydrolysed from TMOS is removed. Then base catalysis and additional water are added to cause gel formation is a nonalcoholic solvent. The MF aerogels were prepared for HRTEM by fracturing them on a stereo microscope stage with razor knife so that fractured pieces with smooth flat surfaces could be selected for platinum-carbon replication. The two silica (TMOS) aerogels were both transparent and difficult to see. These aerogels were fractured on a stereo microscope stage with tweezers. 6 refs., 4 figs.

  15. Topological Insulators

    Microsoft Academic Search

    M. Z. Hasan; C. L. Kane

    2010-01-01

    Topological insulators are electronic materials that have a bulk band gap\\u000alike an ordinary insulator, but have protected conducting states on their edge\\u000aor surface. The 2D topological insulator is a quantum spin Hall insulator,\\u000awhich is a close cousin of the integer quantum Hall state. A 3D topological\\u000ainsulator supports novel spin polarized 2D Dirac fermions on its surface.

  16. The aerocapacitor: A carbon aerogel based supercapacitor

    SciTech Connect

    Mayer, S.T.; Pekala, R.W.; Kaschmitter, J.L.

    1992-12-01

    During the 1980`s, a wide variety of carbon foams, formed by the pyrolysis of polymeric foams, were developed at several Department of Energy Laboratories. These foams are known for their monolithic structure and the ability to tailor their critical parameters (e.g. porosity, density). Lawrence Livermore National Laboratory (LLNL) exclusively developed a unique type of carbon foam, known as carbon aerogels. Carbon aerogels are a special class of open-cell foams with (1) homogeneous ultrafine particle and pore size, (2) very large useful surface area per unit volume, and (3) monolithic structure, that yields (4) excellent electrical conductivity due to the intimate connection of the particles. We have applied carbon aerogels to make an ``Aerocapacitor``; a high power- and energy-density electrochemical double layer capacitor (EDLC) that uses carbon aerogels as electrodes. Carbon aerogel surface areas range from about 100 to 700 m{sup 2}/cc (as measured by BET analysis), with bulk densities of 0.05 to 1.0 g/cm{sup 3} and their morphology allows stored energy to be released rapidly, resulting in high power-densities.

  17. The aerocapacitor: A carbon aerogel based supercapacitor

    SciTech Connect

    Mayer, S.T.; Pekala, R.W.; Kaschmitter, J.L.

    1992-12-01

    During the 1980's, a wide variety of carbon foams, formed by the pyrolysis of polymeric foams, were developed at several Department of Energy Laboratories. These foams are known for their monolithic structure and the ability to tailor their critical parameters (e.g. porosity, density). Lawrence Livermore National Laboratory (LLNL) exclusively developed a unique type of carbon foam, known as carbon aerogels. Carbon aerogels are a special class of open-cell foams with (1) homogeneous ultrafine particle and pore size, (2) very large useful surface area per unit volume, and (3) monolithic structure, that yields (4) excellent electrical conductivity due to the intimate connection of the particles. We have applied carbon aerogels to make an Aerocapacitor''; a high power- and energy-density electrochemical double layer capacitor (EDLC) that uses carbon aerogels as electrodes. Carbon aerogel surface areas range from about 100 to 700 m[sup 2]/cc (as measured by BET analysis), with bulk densities of 0.05 to 1.0 g/cm[sup 3] and their morphology allows stored energy to be released rapidly, resulting in high power-densities.

  18. Volatiles in interplanetary dust particles and aerogels

    NASA Technical Reports Server (NTRS)

    Gibson, E. K., Jr.; Harmetz, C. P.

    1991-01-01

    Volatiles measured in 25 interplanetary dust particles (IDPs) are a mixture of both indigenous materials and contaminants associated with the collection and processing of the ODPs prior to analysis. Most IDPs have been collected in the stratosphere using a silicone oil/freon mixture (20:1 ratio) coated on collector plates. Studies have shown that silicone oil, freon and hexane residues remain with the ODPs, despite attempts to clean the IDPs. Analysis of the IDPs with the LMMS-technique produces spectra with a mixture of indigeneous and contaminants components. The contamination signal can be identified and removed; however, the contamination signal may obscure some of the indigeneous component's signal. Employing spectra stripping techniques, the indigenous volatile constituents associated with the IDPs can be identified. Volatiles are similar to those measured in CI or CM carbonaceous chondrites. Collection of IDPs in low-Earth orbit utilizing a Cosmic Dust Collection Facility attached to Space Station Freedom has been proposed. The low-density material aerogel has been proposed as a collection substrate for IDPs. Our studies have concentrated on identifying volatile contaminants that are associated with aerogel. We have found that solvents used for the preparation of aerogel remain in aerogel and methods must be developed for removing the entrapped solvents before aerogels can be used for an IDP collection substrate.

  19. Progress in movable blanket insulation systems for greenhouses

    SciTech Connect

    Roberts, W.J.; Mears, D.R.; Simpkins, J.C.; Cipolletti, J.P.

    1981-01-01

    The heat transfer coefficient of an uninsulated greenhouse of 4.59 W/m/sup 2/K can be reduced to a value of 1.93 to 3.59 W/m/sup 2/K, depending upon the type of material used and the effectiveness of closure of the mechanical system. The open, woven-cloth materials tested offer significant energy savings, handle well mechanically, drain condensate, and have a potential to double as shading materials in the summer. The thermally opaque and air tight materials tested offer significantly increased energy savings, but provision must be provided to drain off condensation if the materials do not self drain. Some of these materials were found somewhat harder to handle and bulkier to store than the open, woven cloth. It has also been shown that aluminizing the upper surface of a curtain can increase heat savings if the edges are well sealed. Also, some opaque and aluminized materials have a potential use for photoperiod control.

  20. Insulation Station

    NSDL National Science Digital Library

    Twin Cities Public Television

    2013-01-01

    In this physical sciences activity, learners explore insulation. Leaners investigate how insulation can be used to slow down the conduction of heat from one side of a wall to the other. Learners are challenged with designing the best way to insulate a cup to prevent ice cubes from melting.

  1. High strength air-dried aerogels

    DOEpatents

    Coronado, Paul R.; Satcher, Jr., Joe H.

    2012-11-06

    A method for the preparation of high strength air-dried organic aerogels. The method involves the sol-gel polymerization of organic gel precursors, such as resorcinol with formaldehyde (RF) in aqueous solvents with R/C ratios greater than about 1000 and R/F ratios less than about 1:2.1. Using a procedure analogous to the preparation of resorcinol-formaldehyde (RF) aerogels, this approach generates wet gels that can be air dried at ambient temperatures and pressures. The method significantly reduces the time and/or energy required to produce a dried aerogel compared to conventional methods using either supercritical solvent extraction. The air dried gel exhibits typically less than 5% shrinkage.

  2. Slotted Polyimide-Aerogel-Filled-Waveguide Arrays

    NASA Technical Reports Server (NTRS)

    Rodriguez-Solis, Rafael A.; Pacheco, Hector L.; Miranda, Felix A.; Meador, Mary Ann B.

    2013-01-01

    Polyimide aerogels were considered to serve as a filling for millimeter-wave waveguides. While these waveguides present a slightly higher loss than hollow waveguides, they have less losses than Duroid substrate integrated waveguides (less than 0.15 dB at Ka-band, in a 20 mm section), and exhibit an order of magnitude of mass reduction when compared to commercial waveguides. A Ka-band slotted aerogel-filled-waveguide array was designed, which provided the same gain (9 dBi) as its standard waveguide counterpart, and a slotted aerogel-filled-waveguide array using folded-slots was designed for comparison, obtaining a gain of 9 dB and a bandwidth of 590 MHz.

  3. Ambient-pressure silica aerogel films

    SciTech Connect

    Prakash, S.S. [New Mexico Univ., Albuquerque, NM (United States); Brinker, C.J. [New Mexico Univ., Albuquerque, NM (United States)]|[Sandia National Labs., Albuquerque, NM (United States); Hurd, A.J. [Sandia National Labs., Albuquerque, NM (United States)

    1994-12-31

    Very highly porous (aerogel) silica films with refractive index in the range 1.006--1.05 (equivalent porosity 98.5--88%) were prepared by an ambient-pressure process. It was shown earlier using in situ ellipsometric imaging that the high porosity of these films was mainly attributable to the dilation or `springback` of the film during the final stage of drying. This finding was irrefutably reconfirmed by visually observing a `springback` of >500% using environmental scanning electron microscopy (ESEM). Ellipsometry and ESEM also established the near cent per cent reversibility of aerogel film deformation during solvent intake and drying. Film thickness profile measurements (near the drying line) for the aerogel, xerogel and pure solvent cases are presented from imaging ellipsometry. The thickness of these films (crack-free) were controlled in the range 0.1-3.5 {mu}m independent of refractive index.

  4. Purging of a tank-mounted multilayer insulation system by gas diffusion

    Microsoft Academic Search

    I. E. Sumner

    1978-01-01

    The investigation was conducted on a multilayer insulation (MLI) system mounted on a spherical liquid hydrogen propellant tank. The MLI consisted of two blankets of insulation each containing 15 double-aluminized Mylar radiation shields separated by double silk net spacers. The gaseous nitrogen initially contained within the MLI system and vacuum chamber was purged with gaseous helium introduced both underneath the

  5. Monolithic aerogels with nanoporous crystalline phases

    NASA Astrophysics Data System (ADS)

    Daniel, Christophe; Guerra, Gaetano

    2015-05-01

    High porosity monolithic aerogels with nanoporous crystalline phases can be obtained from syndiotactic polystyrene and poly(2,6-dimethyl-1,4-phenylene)oxide thermoreversible gels by removing the solvent with supercritical CO2. The presence of crystalline nanopores in the aerogels based on these polymers allows a high uptake associated with a high selectivity of volatile organic compounds from vapor phase or aqueous solutions even at very low activities. The sorption and the fast kinetics make these materials particularly suitable as sorption medium to remove traces of pollutants from water and moist air.

  6. Evaluation of low cost/high temperature insulation, July 1974 - June 1975

    NASA Technical Reports Server (NTRS)

    Strauss, E. L.

    1975-01-01

    Six fiber products and six insulation blankets comprising silica, alumina, zirconia, mullite, and mixed ceramic systems were subjected to furnace exposures up to 500 hours at temperatures of 1000 to 1600 C and evaluated for chemical and dimensional stability and for changes in thermal conductivity. Alumina, zirconia, and mullite fibers were fabricated into reusable surface insulation (RSI) tile by water-felting and reimpregnation with ethyl silicate. Specimens were exposed to 25 thermal cycles at 1200 C and 1400 C and a pressure of 10 and 32 torr, respectively. Production costs for 930 sq m (10,000 sq ft) of blanket insulation and of alumina RSI tile were developed.

  7. Thermal Performance Testing of Cryogenic Insulation Systems

    NASA Technical Reports Server (NTRS)

    Fesmire, James E.; Augustynowicz, Stan D.; Scholtens, Brekke E.

    2007-01-01

    Efficient methods for characterizing thermal performance of materials under cryogenic and vacuum conditions have been developed. These methods provide thermal conductivity data on materials under actual-use conditions and are complementary to established methods. The actual-use environment of full temperature difference in combination with vacuum-pressure is essential for understanding insulation system performance. Test articles include solids, foams, powders, layered blankets, composite panels, and other materials. Test methodology and apparatus design for several insulation test cryostats are discussed. The measurement principle is liquid nitrogen boil-off calorimetry. Heat flux capability ranges from approximately 0.5 to 500 watts per square meter; corresponding apparent thermal conductivity values range from below 0.01 up to about 60 mW/m- K. Example data for different insulation materials are also presented. Upon further standardization work, these patented insulation test cryostats can be available to industry for a wide range of practical applications.

  8. Multiscale Computer Simulation of Tensile and Compressive Strain in Polymer- Coated Silica Aerogels

    NASA Technical Reports Server (NTRS)

    Good, Brian

    2009-01-01

    While the low thermal conductivities of silica aerogels have made them of interest to the aerospace community as lightweight thermal insulation, the application of conformal polymer coatings to these gels increases their strength significantly, making them potentially useful as structural materials as well. In this work we perform multiscale computer simulations to investigate the tensile and compressive strain behavior of silica and polymer-coated silica aerogels. Aerogels are made up of clusters of interconnected particles of amorphous silica of less than bulk density. We simulate gel nanostructure using a Diffusion Limited Cluster Aggregation (DLCA) procedure, which produces aggregates that exhibit fractal dimensions similar to those observed in real aerogels. We have previously found that model gels obtained via DLCA exhibited stress-strain curves characteristic of the experimentally observed brittle failure. However, the strain energetics near the expected point of failure were not consistent with such failure. This shortcoming may be due to the fact that the DLCA process produces model gels that are lacking in closed-loop substructures, compared with real gels. Our model gels therefore contain an excess of dangling strands, which tend to unravel under tensile strain, producing non-brittle failure. To address this problem, we have incorporated a modification to the DLCA algorithm that specifically produces closed loops in the model gels. We obtain the strain energetics of interparticle connections via atomistic molecular statics, and abstract the collective energy of the atomic bonds into a Morse potential scaled to describe gel particle interactions. Polymer coatings are similarly described. We apply repeated small uniaxial strains to DLCA clusters, and allow relaxation of the center eighty percent of the cluster between strains. The simulations produce energetics and stress-strain curves for looped and nonlooped clusters, for a variety of densities and interaction parameters.

  9. Fusion blankets for high efficiency power cycles

    SciTech Connect

    Powell, J R; Fillo, J A; Horn, F L; Lazareth, O W; Usher, J L

    1980-04-01

    Definitions are given of 10 generic blanket types and the specific blanket chosen to be analyzed in detail from each of the 10 types. Dimensions, compositions, energy depositions and breeding ratios (where applicable) are presented for each of the 10 designs. Ultimately, based largely on neutronics and thermal hyraulics results, breeding an nonbreeding blanket options are selected for further design analysis and integration with a suitable power conversion subsystem.

  10. Low technology high tritium breeding blanket concept

    SciTech Connect

    Gohar, Y.; Baker, C.C.; Smith, D.L.; Billone, M.C.; Cha, Y.S.; Clemmer, R.; Finn, P.A.; Hassanein, A.M.; Johnson, C.E.; Liu, Y.

    1987-10-01

    The main function of this low technology blanket is to produce the necessary tritium for INTOR operation with minimum first wall coverage. The INTOR first wall, blanket, and shield are constrained by the dimensions of the reference design and the protection criteria required for different reactor components and dose equivalent after shutdown in the reactor hall. It is assumed that the blanket operation at commercial power reactor conditions and the proper temperature for power generation can be sacrificed to achieve the highest possible tritium breeding ratio with minimum additional research and developments and minimal impact on reactor design and operation. A set of blanket evaluation criteria has been used to compare possible blanket concepts. Six areas: performance, operating requirements, impact on reactor design and operation, safety and environmental impact, technology assessment, and cost have been defined for the evaluation process. A water-cooled blanket was developed to operate with a low temperature and pressure. The developed blanket contains a 24 cm of beryllium and 6 cm of solid breeder both with a 0.8 density factor. This blanket provides a local tritium breeding ratio of approx.2.0. The water coolant is isolated from the breeder material by several zones which eliminates the tritium buildup in the water by permeation and reduces the changes for water-breeder interaction. This improves the safety and environmental aspects of the blanket and eliminates the costly process of the tritium recovery from the water. 12 refs., 13 tabs.

  11. Toughened Thermal Blanket for MMOD Protection

    NASA Technical Reports Server (NTRS)

    Christiansen, Eric L.; Lear, Dana M.

    2014-01-01

    Thermal blankets are used extensively on spacecraft to provide passive thermal control of spacecraft hardware from thermal extremes encountered in space. Toughened thermal blankets have been developed that greatly improve protection from hypervelocity micrometeoroid and orbital debris (MMOD) impacts. These blankets can be outfitted if so desired with a reliable means to determine the location, depth and extent of MMOD impact damage by incorporating an impact sensitive piezoelectric film. Improved MMOD protection of thermal blankets was obtained by adding selective materials at various locations within the thermal blanket. As given in Figure 1, three types of materials were added to the thermal blanket to enhance its MMOD performance: (1) disrupter layers, near the outside of the blanket to improve breakup of the projectile, (2) standoff layers, in the middle of the blanket to provide an area or gap that the broken-up projectile can expand, and (3) stopper layers, near the back of the blanket where the projectile debris is captured and stopped. The best suited materials for these different layers vary. Density and thickness is important for the disrupter layer (higher densities generally result in better projectile breakup), whereas a highstrength to weight ratio is useful for the stopper layer, to improve the slowing and capture of debris particles.

  12. The requirements for processing tritium recovered from liquid lithium blankets: The blanket interface

    Microsoft Academic Search

    R. G. Clemmer; P. A. Finn; L. R. Greenwood; T. L. Grimm; D. K. Sze; J. R. Bartlit; J. L. Anderson; H. Yoshida; Naruse

    1988-01-01

    We have initiated a study to define a blanket processing mockup for Tritium Systems Test Assembly. Initial evaluation of the requirements of the blanket processing system have been started. The first step of the work is to define the condition of the gaseous tritium stream from the blanket tritium recovery system. This report summarizes this part of the work for

  13. View of a Cometary Impact Into Aerogel

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Closeup view of a cometary impact (upper right) into aerogel was inspected by scientists at a laboratory at the Johnson Space Center hours after the Stardust Sample Return Canister was delivered to the Johnson Space Center from the spacecraft's landing site in Utah.

  14. Manufacturing complex silica aerogel target components

    SciTech Connect

    Defriend Obrey, Kimberly Ann [Los Alamos National Laboratory; Day, Robert D [Los Alamos National Laboratory; Espinoza, Brent F [Los Alamos National Laboratory; Hatch, Doug [Los Alamos National Laboratory; Patterson, Brian M [Los Alamos National Laboratory; Feng, Shihai [Los Alamos National Laboratory

    2008-01-01

    Aerogel is a material used in numerous components in High Energy Density Physics targets. In the past these components were molded into the proper shapes. Artifacts left in the parts from the molding process, such as contour irregularities from shrinkage and density gradients caused by the skin, have caused LANL to pursue machining as a way to make the components.

  15. Morphology-controlled graphene aerogel for energy storage

    NASA Astrophysics Data System (ADS)

    Truong Nguyen, Son; Tien Nguyen, Hoa; Duong, Hai Minh

    2012-02-01

    The development of new anode/cathode materials with highly conductive, non-corrosive, high specific surface area and high porosity for energy storage devices is highly desirable. Graphene aerogels has been focused emergently recently due to novel properties of the graphene. However, the aerogel-based application performance strongly depends on the morphology and structure of the graphene aerogels. The graphene aerogels with low-density have thinner struts, a different distribution of particle sizes, and less internal connectivity. This, in turn, changes the way the material can transport electric charge. As a result, the highest surface area graphene aerogels end up having the worst electrical conductivity, and the most conductive graphene aerogels have lowest surface areas. So the best designs of the developed graphene aerogel nanostructures in terms of pore size, porosity, density and mechanical properties for energy storage devices are essential. In this work, we develop a new fabrication method of graphene aerogels with well-controlled morphology and high electrical conductivity from graphene oxide through the supercritical drying process. The morphology and electrical conductivity of the graphene aerogels are controlled by the precursor contents and the synthesis conditions. The experimental results are very useful for experimentalists deciding the best graphene aerogel nanostructures for their needs.

  16. Nuclear Characteristics of D-D Fusion Reactor Blanket, (II)

    Microsoft Academic Search

    Hideki NAKASHIMA; Masao OHTA; Yasuyuki NAKAO

    1978-01-01

    The nuclear characteristics of the thermal blanket and blanket-shield designs are analyzed to provide a basis for optimizing the blanket design of D-D fusion reactors. The thermal blanket is devised to yield high energy deposition in a compact blanket through the use of neutron multiplier and energy converter with 1\\/v neutron absorption cross section. The blanket-shield design, on the other

  17. Thermal insulator

    SciTech Connect

    Yamamoto, R.; Asada, Y.; Matsuo, Y.; Mikoda, M.

    1985-07-16

    A thermal insulator comprises an expanded resin body having embedded therein an evacuated powder insulation portion which consists of fine powder and a container of film-like plastics or a film-like composite of plastics and metal for enclosing the powder. The resin body has been expanded by a Freon gas as a blowing agent. Since a Freon gas has a larger molecular diameter than the constituent gases of air, it is less likely to permeate through the container than air. Thus present invention provides a novel composite insulator which fully utilizes the benefits of vacuum insulation without necessitating a strong and costly material for a vacuum container.

  18. Thermal control of ceramic breeder blankets

    Microsoft Academic Search

    A. R. Raffray; M. S. Tillack; M. A. Abdou

    1993-01-01

    Thermal control is an important issue for ceramic breeder blankets since the breeder needs to operate within its temperature window for the tritium release and inventory to be acceptable. A thermal control region is applicable not only to situations where the coolant can be run at low temperature, such as for the International Thermonuclear Experimental Reactor (ITER) base blanket, but

  19. Low technology high tritium breeding blanket concept

    Microsoft Academic Search

    Y. Gohar; C. C. Baker; D. L. Smith; M. C. Billone; Y. S. Cha; R. Clemmer; P. A. Finn; A. M. Hassanein; C. E. Johnson; Y. Liu

    1987-01-01

    The main function of this low technology blanket is to produce the necessary tritium for INTOR operation with minimum first wall coverage. The INTOR first wall, blanket, and shield are constrained by the dimensions of the reference design and the protection criteria required for different reactor components and dose equivalent after shutdown in the reactor hall. It is assumed that

  20. Accidental tritium release from solid breeding blankets

    Microsoft Academic Search

    D. F. Holland; B. J. Merrill

    1983-01-01

    Vulnerability of tritium in a solid breeding material has been determined for accidents involving failure of the barrier between the blanket and reactor building. Two breeding materials were analyzed, lithium aluminate and lithium oxide. Accident scenarios included either continuation or termination of the blanket cooling and helium purge flow. The results showed that with the purge flow continued, tritium in

  1. (D,T) Driven thorium hybrid blankets

    SciTech Connect

    Al-Kusayer, T.A.; Khan, S.; Sahin, S.

    1983-12-01

    Recently, a project has started, with the aim to establish the neutronic performance and the basic design of an experimental fusionfission (hybrid) reactor facility, called AYMAN, in cylinderical geometry. The fusion reactor will have to be simulated by a (D,T) neutron generator. Fissile and fertile fuel will have to surround the neutron generator as a cylinderical blanket to simulate the boundary conditions of the hybrid blanket in a proper way. This geometry is consistent with Tandem Mirror Hybrid Blanket design and with most of the ICF blanket designs. A similar experimental installation will become operational around 1984 at the Swiss Federal Institute of Technology in Lausanne, Switzerland known under the project LOTUS. Due to the limited dimensions of the experimental cavity of the LOTUS-hybrid reactor, the LOTUS blankets have to be designed in plane geometry. Also, the bulky form of the Haefely neutron generator of the LOTUS facility obliges one to design a blanket in the plane geometry. This results in a vacuum left boundary conditions for the LOTUS blanket. The importance of a reflecting left boundary condition on the overall neutronic performance of a hybrid blanket has been analyzed in previous work in detail.

  2. Highly compressible 3D periodic graphene aerogel microlattices

    NASA Astrophysics Data System (ADS)

    Zhu, Cheng; Han, T. Yong-Jin; Duoss, Eric B.; Golobic, Alexandra M.; Kuntz, Joshua D.; Spadaccini, Christopher M.; Worsley, Marcus A.

    2015-04-01

    Graphene is a two-dimensional material that offers a unique combination of low density, exceptional mechanical properties, large surface area and excellent electrical conductivity. Recent progress has produced bulk 3D assemblies of graphene, such as graphene aerogels, but they possess purely stochastic porous networks, which limit their performance compared with the potential of an engineered architecture. Here we report the fabrication of periodic graphene aerogel microlattices, possessing an engineered architecture via a 3D printing technique known as direct ink writing. The 3D printed graphene aerogels are lightweight, highly conductive and exhibit supercompressibility (up to 90% compressive strain). Moreover, the Young's moduli of the 3D printed graphene aerogels show an order of magnitude improvement over bulk graphene materials with comparable geometric density and possess large surface areas. Adapting the 3D printing technique to graphene aerogels realizes the possibility of fabricating a myriad of complex aerogel architectures for a broad range of applications.

  3. Highly compressible 3D periodic graphene aerogel microlattices.

    PubMed

    Zhu, Cheng; Han, T Yong-Jin; Duoss, Eric B; Golobic, Alexandra M; Kuntz, Joshua D; Spadaccini, Christopher M; Worsley, Marcus A

    2015-01-01

    Graphene is a two-dimensional material that offers a unique combination of low density, exceptional mechanical properties, large surface area and excellent electrical conductivity. Recent progress has produced bulk 3D assemblies of graphene, such as graphene aerogels, but they possess purely stochastic porous networks, which limit their performance compared with the potential of an engineered architecture. Here we report the fabrication of periodic graphene aerogel microlattices, possessing an engineered architecture via a 3D printing technique known as direct ink writing. The 3D printed graphene aerogels are lightweight, highly conductive and exhibit supercompressibility (up to 90% compressive strain). Moreover, the Young's moduli of the 3D printed graphene aerogels show an order of magnitude improvement over bulk graphene materials with comparable geometric density and possess large surface areas. Adapting the 3D printing technique to graphene aerogels realizes the possibility of fabricating a myriad of complex aerogel architectures for a broad range of applications. PMID:25902277

  4. Evaluating Dimethyldiethoxysilane for use in Polyurethane Crosslinked Silica Aerogels

    NASA Technical Reports Server (NTRS)

    Randall, Jason P.; Meador, Mary Ann B.; Jana, Sadhan C.

    2008-01-01

    Silica aerogels are highly porous materials which exhibit exceptionally low density and thermal conductivity. Their "pearl necklace" nanostructure, however, is inherently weak; most silica aerogels are brittle and fragile. The strength of aerogels can be improved by employing an additional crosslinking step using isocyanates. In this work, dimethyldiethoxysilane (DMDES) is evaluated for use in the silane backbone of polyurethane crosslinked aerogels. Approximately half of the resulting aerogels exhibited a core/shell morphology of hard crosslinked aerogel surrounding a softer, uncrosslinked center. Solid state NMR and scanning electron microscopy results indicate the DMDES incorporated itself as a conformal coating around the outside of the secondary silica particles, in much the same manner as isocyanate crosslinking. Response surface curves were generated from compression data, indicating levels of reinforcement comparable to that in previous literature, despite the core/shell morphology.

  5. Highly compressible 3D periodic graphene aerogel microlattices

    PubMed Central

    Zhu, Cheng; Han, T. Yong-Jin; Duoss, Eric B.; Golobic, Alexandra M.; Kuntz, Joshua D.; Spadaccini, Christopher M.; Worsley, Marcus A.

    2015-01-01

    Graphene is a two-dimensional material that offers a unique combination of low density, exceptional mechanical properties, large surface area and excellent electrical conductivity. Recent progress has produced bulk 3D assemblies of graphene, such as graphene aerogels, but they possess purely stochastic porous networks, which limit their performance compared with the potential of an engineered architecture. Here we report the fabrication of periodic graphene aerogel microlattices, possessing an engineered architecture via a 3D printing technique known as direct ink writing. The 3D printed graphene aerogels are lightweight, highly conductive and exhibit supercompressibility (up to 90% compressive strain). Moreover, the Young's moduli of the 3D printed graphene aerogels show an order of magnitude improvement over bulk graphene materials with comparable geometric density and possess large surface areas. Adapting the 3D printing technique to graphene aerogels realizes the possibility of fabricating a myriad of complex aerogel architectures for a broad range of applications. PMID:25902277

  6. Insulation materials

    Microsoft Academic Search

    R. S. Graves; D. C. Wysocki

    1991-01-01

    This volume reflects the interest in this decade of conserving energy and protecting he environment. The Symposium and the resulting STP clearly demonstrate the Committee's objective of providing timely information on the testing, characterization, use, and development of thermal insulations. In the 1970s and 1980s, interest and activity in thermal insulation was spurred by the growing recognition of the need

  7. The breeder blanket interface (BBI) to TSTA

    SciTech Connect

    Finn, P.A.; Clemmer, R.G.; Greenwood, L.; Lide, A.; Sze, D.K.; Anderson, J.L.; Sherman, R.; Bartlit, J.R.; Naruse, Y.; Yoshida, H.

    1989-03-01

    A breeder blanket interface for an aqueous lithium salt blanket is defined for TSTA. High calculated radiolysis rates result in a high overpressure in the blanket and the need for a depressurizer and a recombiner system. High projected corrosion rates for stainless steel and for beryllium result in high activity levels in the blanket and the possible dissolution of the beryllium balls. The required tritium processing systems are complex, involving seven separation steps. A flow sheet is presented of the needed tritium systems. The main processing units to recover tritium from the salt solution are a flash evaporator with condenser, a water distillation unit, and a vapor phase chemical exchange (VPCE) unit. The gas product stream from the blanket has an H/T ratio of 10/sup 5/ which requires a dedicated cryodistillation unit of very high capacity. This unit has a first column with a diameter of almost one meter to decrease the H/T ratio to 10.

  8. Observation of viscoelasticity in boron nitride nanosheet aerogel.

    PubMed

    Zeng, Xiaoliang; Ye, Lei; Sun, Rong; Xu, Jianbin; Wong, Ching-Ping

    2015-06-24

    The viscoelasticity of boron nitride nanosheet (BNNS) aerogel has been observed and investigated. It is found that the BNNS aerogel has a high damping ratio (0.2), while it exhibits lightweight and negligible temperature dependence below 180 °C. The creep behavior of the BNNS aerogel markedly demonstrates its strain dependence on stress magnitude and temperature, and can be well simulated by the classical models. PMID:26068059

  9. Raman Scattering in Silica and Silicophosphate Aerogels.

    NASA Astrophysics Data System (ADS)

    Walden, Barbara L.

    Silicate aerogels are versatile, lightweight, and highly porous materials which are formed by the critical point drying of gelled organic silicate solutions. Aerogels have a complicated microstructure consisting of small nano -scale grains linked together into chains and higher-order clusters. Both silica and silicophosphate aerogels were fabricated for this study. Their bulk density was measured and their morphology was characterized by transmission electron microscopy and scanning electron microscopy. Finally, Raman spectra were taken over the range 5-1100 cm ^{-1}. For aerogels the Raman scattering curve can be separated into three different spectroscopic (and hence length-scale regimes). At very low frequencies (5-70 cm ^{-1}), Raman spectra reveal a "particle band" that arises from the discrete particulate character of the gels at very small size scales. The location of the particle band maximum was related to the particle size, as confirmed by TEM measurements of the nanoscale structure in the aerogels. Increasing the amount of time a wet gel was allowed to age before being dried caused the particle peak to sharpen and grow in intensity, reflecting the ongoing condensation of lightly crosslinked silica tetrahedra within and along the surfaces of the particles. The scattering at intermediate frequencies (30 -200 cm^{-1}), which arises from modes within the elementary particles, followed a power law in frequency of the sort predicted for the vibrations of self-similar fractal structures. The power law exponent changed with the initial gel preparation conditions and decreased as age time increased. Spectra at higher frequencies imply an abundance of cyclical ring structures and Si-OH bonds which, along with the peaks characteristic of bulk silica glass, grew and became better defined with increasing age time. This provided a physical picture for the origin of intermediate scale disorder. The addition of P_2O _5 affected the aerogel microstructure. Like silicon, phosphorus is a network former which readily bonds with oxygen in a tetrahedral configuration. The addition of phosphorus, even at very low concentrations, reduced the mean particle size. This was demonstrated both by the TEM micrographs and by the change in position of the particle peak in Raman scattering.

  10. Optical and radiographical characterization of silica aerogel for Cherenkov radiator

    E-print Network

    Tabata, Makoto; Hatakeyama, Yoshikiyo; Kawai, Hideyuki; Morita, Takeshi; Nishikawa, Keiko

    2012-01-01

    We present optical and X-ray radiographical characterization of silica aerogels with refractive index from 1.05 to 1.07 for a Cherenkov radiator. A novel pin-drying method enables us to produce highly transparent hydrophobic aerogels with high refractive index by shrinking wet-gels. In order to investigate the uniformity in the density (i.e., refractive index) of an individual aerogel monolith, we use the laser Fraunhofer method, an X-ray absorption technique, and Cherenkov imaging by a ring imaging Cherenkov detector in a beam test. We observed an increase in density at the edge of the aerogel tiles, produced by pin-drying.

  11. Silk fibroin aerogels: potential scaffolds for tissue engineering applications.

    PubMed

    Mallepally, Rajendar R; Marin, Michael A; Surampudi, Vasudha; Subia, Bano; Rao, Raj R; Kundu, Subhas C; McHugh, Mark A

    2015-01-01

    Silk fibroin (SF) is a natural protein, which is derived from the Bombyx mori silkworm. SF based porous materials are extensively investigated for biomedical applications, due to their biocompatibility and biodegradability. In this work, CO2 assisted acidification is used to synthesize SF hydrogels that are subsequently converted to SF aerogels. The aqueous silk fibroin concentration is used to tune the morphology and textural properties of the SF aerogels. As the aqueous fibroin concentration increases from 2 to 6?wt%, the surface area of the resultant SF aerogels increases from 260 to 308?m(2)?g(-1) and the compressive modulus of the SF aerogels increases from 19.5 to 174?kPa. To elucidate the effect of the freezing rate on the morphological and textural properties, SF cryogels are synthesized in this study. The surface area of the SF aerogels obtained from supercritical CO2 drying is approximately five times larger than the surface area of SF cryogels. SF aerogels exhibit distinct pore morphology compared to the SF cryogels. In vitro cell culture studies with human foreskin fibroblast cells demonstrate the cytocompatibility of the silk fibroin aerogel scaffolds and presence of cells within the aerogel scaffolds. The SF aerogels scaffolds created in this study with tailorable properties have potential for applications in tissue engineering. PMID:25953953

  12. Transparent monolithic metal ion containing nanophase aerogels

    SciTech Connect

    Risen, W. M., Jr.; Hu, X.; Ji, S.; Littrell, K.

    1999-12-01

    The formation of monolithic and transparent transition metal containing aerogels has been achieved through cooperative interactions of high molecular weight functionalized carbohydrates and silica precursors, which strongly influence the kinetics of gelation. After initial gelation, subsequent modification of the ligating character of the system, coordination of the group VIII metal ions, and supercritical extraction afford the aerogels. The structures at the nanophase level have been probed by photon and electron transmission and neutron scattering techniques to help elucidate the basis for structural integrity together with the small entity sizes that permit transparency in the visible range. They also help with understanding the chemical reactivities of the metal-containing sites in these very high surface area materials. These results are discussed in connection with new reaction studies.

  13. Magnetic hydrophobic nanocomposites: Silica aerogel/maghemite

    NASA Astrophysics Data System (ADS)

    Mendoza Zélis, P.; Fernández van Raap, M. B.; Socolovsky, L. M.; Leyva, A. G.; Sánchez, F. H.

    2012-08-01

    Magnetic hydrophobic aerogels (MHA) in the form of nanocomposites of silica and maghemite (?-Fe2O3) were prepared by one step sol-gel procedure followed by supercritical solvent extraction. Silica alcogels were obtained from TEOS, MTMS, methanol and H2O, and Fe(III) nitrate as magnetic precursor. The hydrophobic property was achieved using the methytrimethoxysilane (MTMS) as co-precursor for surface modification. The so produced nanocomposite aerogels are monolithic, hydrophobic and magnetic. The interconnected porous structure hosts ?6 nm size ?-Fe2O3 particles, has a mean pore diameter of 5 nm, and a specific surface area (SSA) of 698 m²/g. Medium range structure of MHA is determined by SAXS, which displays the typical fractal power law behavior with primary particle radius of ?1 nm. Magnetic properties of the nanoparticle ensembles hosted in them are studied by means of dc-magnetometry.

  14. ADVANCED HIGH PERFORMANCE SOLID WALL BLANKET CONCEPTS

    SciTech Connect

    WONG, CPC; MALANG, S; NISHIO, S; RAFFRAY, R; SAGARA, S

    2002-04-01

    OAK A271 ADVANCED HIGH PERFORMANCE SOLID WALL BLANKET CONCEPTS. First wall and blanket (FW/blanket) design is a crucial element in the performance and acceptance of a fusion power plant. High temperature structural and breeding materials are needed for high thermal performance. A suitable combination of structural design with the selected materials is necessary for D-T fuel sufficiency. Whenever possible, low afterheat, low chemical reactivity and low activation materials are desired to achieve passive safety and minimize the amount of high-level waste. Of course the selected fusion FW/blanket design will have to match the operational scenarios of high performance plasma. The key characteristics of eight advanced high performance FW/blanket concepts are presented in this paper. Design configurations, performance characteristics, unique advantages and issues are summarized. All reviewed designs can satisfy most of the necessary design goals. For further development, in concert with the advancement in plasma control and scrape off layer physics, additional emphasis will be needed in the areas of first wall coating material selection, design of plasma stabilization coils, consideration of reactor startup and transient events. To validate the projected performance of the advanced FW/blanket concepts the critical element is the need for 14 MeV neutron irradiation facilities for the generation of necessary engineering design data and the prediction of FW/blanket components lifetime and availability.

  15. Multivariable optimization of fusion reactor blankets

    SciTech Connect

    Meier, W.R.

    1984-04-01

    The optimization problem consists of four key elements: a figure of merit for the reactor, a technique for estimating the neutronic performance of the blanket as a function of the design variables, constraints on the design variables and neutronic performance, and a method for optimizing the figure of merit subject to the constraints. The first reactor concept investigated uses a liquid lithium blanket for breeding tritium and a steel blanket to increase the fusion energy multiplication factor. The capital cost per unit of net electric power produced is minimized subject to constraints on the tritium breeding ratio and radiation damage rate. The optimal design has a 91-cm-thick lithium blanket denatured to 0.1% /sup 6/Li. The second reactor concept investigated uses a BeO neutron multiplier and a LiAlO/sub 2/ breeding blanket. The total blanket thickness is minimized subject to constraints on the tritium breeding ratio, the total neutron leakage, and the heat generation rate in aluminum support tendons. The optimal design consists of a 4.2-cm-thick BeO multiplier and 42-cm-thick LiAlO/sub 2/ breeding blanket enriched to 34% /sup 6/Li.

  16. Carbonates Found in Stardust Aerogel Tracks

    NASA Technical Reports Server (NTRS)

    Wirick, S.; Leroux, H.; Tomeoka, K.; Zolensky, M.; Flynn, T.; Tyliszczak, T.; Butterworth, A.; Tomioka, N.; Ohnishi, I.; Messenger, K. Nakamura; Sandford, S.; Keller, L.; Jacobsen, C.

    2007-01-01

    Preliminary examination of particles collected from Comet Wild 2 suggest that this comet is chondritic and formed under multiple processes. The lack of any hydrated minerals strongly suggests that most, if not all of these processes were anhydrous [1,2,3]. However, carbonates were found in particles extracted from 4 different tracks in the aerogel. It is our belief that these carbonates have a terrestrial origin and are a contaminant in these samples.

  17. Method for making monolithic metal oxide aerogels

    SciTech Connect

    Coronado, Paul R. (Livermore, CA)

    1999-01-01

    Transparent, monolithic metal oxide aerogels of varying densities are produced using a method in which a metal alkoxide solution and a catalyst solution are prepared separately and reacted. The resulting hydrolyzed-condensed colloidal solution is gelled, and the wet gel is contained within a sealed, but gas permeable, containment vessel during supercritical extraction of the solvent. The containment vessel is enclosed within an aqueous atmosphere that is above the supercritical temperature and pressure of the solvent of the metal alkoxide solution.

  18. Method for making monolithic metal oxide aerogels

    SciTech Connect

    Coronado, P.R.

    1999-09-28

    Transparent, monolithic metal oxide aerogels of varying densities are produced using a method in which a metal alkoxide solution and a catalyst solution are prepared separately and reacted. The resulting hydrolyzed-condensed colloidal solution is gelled, and the wet gel is contained within a sealed, but gas permeable, containment vessel during supercritical extraction of the solvent. The containment vessel is enclosed within an aqueous atmosphere that is above the supercritical temperature and pressure of the solvent of the metal alkoxide solution.

  19. Contraction of aerogels by superfluid order

    NASA Astrophysics Data System (ADS)

    Thibault, P.; Préjean, J. J.; Puech, L.

    1996-01-01

    We measured the thermal expansion dL/L of silica aerogels filled with liquid4He. A rapid contraction of the gel is observed at T co slightly below T ? at decreasing T. We found an additional expansion due to fountain pressure gradients. It suddendly decreases at a temperature T c(< T co). We interpret T c as a critical temperature above which superfluid exists only in some regions.

  20. Use of silica aerogels in Cherenkov counters

    Microsoft Academic Search

    Yu. N. Kharzheev

    2008-01-01

    Silica aerogel is widely used as a radiator for Cherenkov detectors. It is a highly porous, low-density, and transparent substance\\u000a with refractive index n ranging between the values of n n ? 1.3 for condensed phases. The review is devoted to the consideration of various factors affecting the identification of\\u000a particles in Cherenkov counters: the chromatic aberration, the number of

  1. Water-cooled solid-breeder blanket concept for ITER

    Microsoft Academic Search

    Y. Gohar; C. C. Baker; H. Attaya; M. Billone; R. C. Clemmer; P. A. Finn; A. Hassanein; C. E. Johnson; S. Majumdar; R. F. Mattas

    1989-01-01

    A water cooled solid-breeder blanket concept was developed for ITER. The main function of this blanket is to produce the necessary tritium for the ITER operation. Several design features are incorporated in this blanket concept to increase its attractiveness. The main features are the following: (a) a multilayer concept which reduces fabrication cost; (b) a simple blanket configuration which results

  2. Venting through multiple-layer insulation on Space Station Freedom. II - Ascent rate pressure chamber testing

    NASA Technical Reports Server (NTRS)

    Sharp, Jeffrey B.; Buitekant, Alan; Fay, John F.; Holladay, Jon B.

    1993-01-01

    A test was conducted to determine the venting characteristics of the multiple-layer insulation (MLI) to be installed on the Space Station Freedom (SSF). A full MLI blanket with inter-blanket joints was installed onto a model of a section of the SSF pressure wall, support structure, and debris shield. Data were taken from this test and were used to predict the venting of the actual Space Station pressure-wall/MLI/debris-shield assemply during launch and possible re-entry. It was found that the pressure differences across the debris shields and MLI blankets were well within the specified limits in all cases.

  3. Structure and performance of carbon aerogel electrodes

    SciTech Connect

    Pekala, R.W.; Mayer, S.T.; Poco, J.F.; Kaschmitter, J.L.

    1994-03-01

    The chemistry and physics of small clusters of atoms (1--100 nm) has received considerable attention in recent years because these assemblies often have properties between the molecular and bulk solid-state limits. The different properties can be explained in terms of the large fraction of atoms that are at the surface of a cluster as compared to the interior. Although the synthesis and properties of metal and. semiconductor clusters, metallocarbohedrenes, fullerenes, and nanotubes are the subject of extensive investigations, little attention has been paid to cluster-assembled porous materials. This oversight is of particular interest to us since we believe that aerogels are one of the few monolithic materials presently available where the benefits of cluster assembly can be demonstrated. In particular, the unique optical, thermal, acoustic, mechanical, and electrical properties of aerogels are directly related to their nanostructure, which is composed of interconnected particles (3--30 nm) with small interstitial pores (< 50 nm). This structure leads to extremely high surface areas (400--1100 m{sup 2}/g) with a large fraction of the atoms covering the surface of the interconnected particles. As a result of these structural features, carbon aerogels are finding applications as electrodes in supercapacitors with high energy and power densities.

  4. Cutting Silica Aerogel for Particle Extraction

    NASA Technical Reports Server (NTRS)

    Tsou, P.; Brownlee, D. E.; Glesias, R.; Grigoropoulos, C. P.; Weschler, M.

    2005-01-01

    The detailed laboratory analyses of extraterrestrial particles have revolutionized our knowledge of planetary bodies in the last three decades. This knowledge of chemical composition, morphology, mineralogy, and isotopics of particles cannot be provided by remote sensing. In order to acquire these detail information in the laboratories, the samples need be intact, unmelted. Such intact capture of hypervelocity particles has been developed in 1996. Subsequently silica aerogel was introduced as the preferred medium for intact capturing of hypervelocity particles and later showed it to be particularly suitable for the space environment. STARDUST, the 4th NASA Discovery mission to capture samples from 81P/Wild 2 and contemporary interstellar dust, is the culmination of these new technologies. In early laboratory experiments of launching hypervelocity projectiles into aerogel, there was the need to cut aerogel to isolate or extract captured particles/tracks. This is especially challenging for space captures, since there will be many particles/tracks of wide ranging scales closely located, even collocated. It is critical to isolate and extract one particle without compromising its neighbors since the full significance of a particle is not known until it is extracted and analyzed. To date, three basic techniques have been explored: mechanical cutting, lasers cutting and ion beam milling. We report the current findings.

  5. Cellulose nanofibrils aerogels generated from jute fibers.

    PubMed

    Lin, Jinyou; Yu, Liangbo; Tian, Feng; Zhao, Nie; Li, Xiuhong; Bian, Fenggang; Wang, Jie

    2014-08-30

    In this work, we report the cellulose nanofibrils extracted from the pristine jute fibers via the pretreatments followed by the TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidation and mechanical disintegration. The effects of pretreatments by using the NaOH solution and dimethyl sulfoxide solvent on the fiber morphology and macro/micro-structures were investigated by polarizing microscope and synchrotron radiation wide/small-angle X-ray scattering (WAXS/SAXS). The cellulose nanofibrils exhibit a diameter ranging from 5 nm to 20 nm and a length of several micrometers, which have been assembled into cellulose aerogels by the lyophilization of as-prepared nanofibrils dispersions with various concentrations. The results indicated that the hierarchical structures of as-prepared cellulose aerogels were dependent on the dispersion concentrations. The WAXS results show that the typical cellulose aerogels are coexistence of cellulose I and cellulose II, which has a great promise for many potential applications, such as pharmaceutical, liquid filtration, catalysts, bio-nanocomposites, and tissue engineering scaffolds. PMID:24815398

  6. Computer Simulation of Fracture in Aerogels

    NASA Technical Reports Server (NTRS)

    Good, Brian S.

    2006-01-01

    Aerogels are of interest to the aerospace community primarily for their thermal properties, notably their low thermal conductivities. While the gels are typically fragile, recent advances in the application of conformal polymer layers to these gels has made them potentially useful as lightweight structural materials as well. In this work, we investigate the strength and fracture behavior of silica aerogels using a molecular statics-based computer simulation technique. The gels' structure is simulated via a Diffusion Limited Cluster Aggregation (DLCA) algorithm, which produces fractal structures representing experimentally observed aggregates of so-called secondary particles, themselves composed of amorphous silica primary particles an order of magnitude smaller. We have performed multi-length-scale simulations of fracture in silica aerogels, in which the interaction b e e n two secondary particles is assumed to be described by a Morse pair potential parameterized such that the potential range is much smaller than the secondary particle size. These Morse parameters are obtained by atomistic simulation of models of the experimentally-observed amorphous silica "bridges," with the fracture behavior of these bridges modeled via molecular statics using a Morse/Coulomb potential for silica. We consider the energetics of the fracture, and compare qualitative features of low-and high-density gel fracture.

  7. An assessment of critical thermal-hydraulic problems in a deuterium-tritium solid breeder blanket

    SciTech Connect

    Misra, B.; Clemmer, R.G.; Smith, D.L.

    1983-09-01

    Steady-state thermal-hydraulic analyses were carried out for the DEMO/STARFIRE fusion reactor based on solid breeder blankets and pressurized water as the coolant. The results of the parametric studies show that a coolant in-tube design, i.e., coolant tubes embedded in solid breeder blanket, with a contact resistance between the coolant tube and the solid breeder tailored to maintain the operating temperature window (i.e., the maximum and the minimum temperature imposed on the solid breeder) is viable. However, design of such a solid breeder blanket will present serious challenges because of uncertainty in the thermophysical properties of breeder materials, the narrow operating temperature window, the close manufacturing tolerances necessary to control the gap conductance, the sensitivity of tritium inventory and tritium extraction to breeder temperature distribution, and the deleterious effect of neutron irradiation on breeder material properties. The study shows that even modest uncertainties in the thermal conductivity of solid breeders, interfacial gap conductances, and operating power levels can have significant impact on blanket design. Therefore, the designer should include the expected variations in these parameters. Experimental programs are needed to quantify the above factors and to develop methods (e.g., insulated coatings) for gap conductance control and in situ recovery of tritium via helium purge gas channels.

  8. Optical and electronic characterization of sol-gel- derived silica aerogels for display and imaging applications

    Microsoft Academic Search

    Sally Ann Cahill

    1999-01-01

    Aerogels are a unique class of ultra low-density solid materials with interconnected pores and porosities up to 98%. Their nanometer-sized structures create remarkable optical, electrical, and structural properties. This dissertation focuses on the optical and electronic properties of silica aerogels foruse in display and imaging applications. Thus the absorption and emission bands of aerogels, the aerogel's response to free electrons,

  9. Fiducial Marks for Location of Particles in Aerogel

    NASA Technical Reports Server (NTRS)

    Jurewicz, A. J. G.; Tsapin, A. I.; Jones, S. M.

    2004-01-01

    If an extraterrestrial sample is captured in aerogel as a collection of particles, it is important to be able to consistently locate individual grains when changing instruments or laboratories. We report on a feasibility study for applying fiducial marks to aerogel nondestructively so that the marks can eventually be used with optical, X-ray or other (manual or automated) location techniques.

  10. Tailoring of morphology and surface properties of syndiotactic polystyrene aerogels.

    PubMed

    Wang, Xiao; Jana, Sadhan C

    2013-05-01

    This study evaluates a method for rendering syndiotactic polystyrene (sPS) aerogels hydrophilic using polyethylene oxide (PEO) of different molecular weights. The highly porous sPS aerogels are inherently hydrophobic although applications involving absorption of moisture and removal of particulate solids may benefit from the high surface area of sPS aerogels provided some degree of hydrophilicity is induced in these materials. In this work, sPS gels are prepared by thermo-reversible gelation in tetrahydrofuran in the presence of PEO. The gels are dried under supercritical conditions to obtain aerogels. The aerogels are characterized by scanning electron microscopy, nitrogen-adsorption porosimetry, helium pycnometry, and contact angle measurements. The data reveal that the pore structures and surface energy can be controlled by varying the concentration and molecular weight of PEO and using different cooling rates during thermo-reversible gelation. In the first case, sPS aerogels, aerogels containing PEO of a low molecular weight or low concentration show superhydrophobic surface presenting the "lotus effect". In the second case, PEO at a higher concentration or with higher molecular weight forms phase-separated domains yielding new hydrophilic macropores (>10 ?m) in the aerogel structures. These macropores contribute to the superhydrophobic surface with the "petal effect". The cooling rate during gelation shows a strong influence on these two cases. PMID:23573990

  11. Highly porous ceramic oxide aerogels having improved flexibility

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B. (Inventor); Nguyen, Baochau N. (Inventor); Guo, Haiquan (Inventor)

    2012-01-01

    Ceramic oxide aerogels having improved flexibility are disclosed. Preferred embodiments exhibit high modulus and other strength properties despite their improved flexibility. The gels may be polymer cross-linked via organic polymer chains to further improve strength properties, without substantially detracting from the improved flexibility. Methods of making such aerogels are also disclosed.

  12. Multifractal Framework Based on Blanket Method

    PubMed Central

    Paskaš, Milorad P.; Reljin, Irini S.; Reljin, Branimir D.

    2014-01-01

    This paper proposes two local multifractal measures motivated by blanket method for calculation of fractal dimension. They cover both fractal approaches familiar in image processing. The first two measures (proposed Methods 1 and 3) support model of image with embedded dimension three, while the other supports model of image embedded in space of dimension three (proposed Method 2). While the classical blanket method provides only one value for an image (fractal dimension) multifractal spectrum obtained by any of the proposed measures gives a whole range of dimensional values. This means that proposed multifractal blanket model generalizes classical (monofractal) blanket method and other versions of this monofractal approach implemented locally. Proposed measures are validated on Brodatz image database through texture classification. All proposed methods give similar classification results, while average computation time of Method 3 is substantially longer. PMID:24578664

  13. Accidental tritium release from solid breeding blankets

    SciTech Connect

    Holland, D.F.; Merrill, B.J.

    1983-01-01

    Vulnerability of tritium in a solid breeding material has been determined for accidents involving failure of the barrier between the blanket and reactor building. Two breeding materials were analyzed, lithium aluminate and lithium oxide. Accident scenarios included either continuation or termination of the blanket cooling and helium purge flow. The results showed that with the purge flow continued, tritium in lithium oxide is more vulnerable than in lithium aluminate. As the blanket cools after reactor shutdown, tritium is desorbed from the lithium oxide because of its temperature dependent solubility. In addition, the diffusion rate in the solid remains high enough for tritium release, even at the temperatures after shutdown. With the purge flow terminated, the rate of tritium release is limited by diffusion along purge channels to the blanket boundary.

  14. Advanced fusion fuel driven AYMAN hybrid blankets

    SciTech Connect

    Sahin, S.; Al-Kusayer, T.A.

    1983-12-01

    Advanced fusion fuel based on the (D,D) reaction has been proposed for a large fusion power plant to supply the fusile fuel for a number of non-breeding satellite (D,T) reactors. Non-breeding (D,T) reactors reveal a higher grade of simplicity and flexibility in the design and utilization. In previous work, the neutronic performance of a potential blanket tailored to the geometrical structure of the experimental facility LOTUS had been analyzed. As the geometry of a LOTUS blankets will be not compatible with a real fusion reactor confinement geometry, the design studies for a new experimental hybrid reactor in cylinderical geometry, called AYMAN, have been initiated. A potential AYMAN blanket will cover the neutron generator in all directions so that such a blanket will reflect the neutron spectrum in a proper way, comparable with the neutron spectrum in a fusion power plant.

  15. Method for preparing a solid phase microextraction device using aerogel

    DOEpatents

    Miller, Fred S. (Bethel Island, CA); Andresen, Brian D. (Livermore, CA)

    2006-10-24

    A sample collection substrate of aerogel and/or xerogel materials bound to a support structure is used as a solid phase microextraction (SPME) device. The xerogels and aerogels may be organic or inorganic and doped with metals or other compounds to target specific chemical analytes. The support structure is typically formed of a glass fiber or a metal wire (stainless steel or kovar). The devices are made by applying gel solution to the support structures and drying the solution to form aerogel or xerogel. Aerogel particles may be attached to the wet layer before drying to increase sample collection surface area. These devices are robust, stable in fields of high radiation, and highly effective at collecting gas and liquid samples while maintaining superior mechanical and thermal stability during routine use. Aerogel SPME devices are advantageous for use in GC/MS analyses due to their lack of interfering background and tolerance of GC thermal cycling.

  16. sup 13 C NMR investigation of crosslinking in organic aerogels

    SciTech Connect

    Ward, R. L.; Pekala, R. W.

    1989-09-15

    Organic aerogels are a special type of low density foam produced from the supercritical drying of resorcinol-formaldehyde (RF) gels. These aerogels have continuous porosity, ultrafine cell/pore sizes (<1000 {angstrom}), and a microstructure composed of interconnected colloidal-like particles with diameters ranging from 30-175 {angstrom}. The particle size, surface area, density, and mechanical properties of the aerogels are largely determined by the catalysts concentration used in the sol-gel polymerization. In order to gain some insight into the crosslinks between RF particles, aerogels were labeled with C-13 formaldehyde at various times in the polymerization. CPMAS and IRCP techniques were used to correlate the relaxation behavior of the C-13 enriched aerogels with their different microstructures. 9 refs., 1 fig., 2 tabs.

  17. Load responsive multilayer insulation performance testing

    NASA Astrophysics Data System (ADS)

    Dye, S.; Kopelove, A.; Mills, G. L.

    2014-01-01

    Cryogenic insulation designed to operate at various pressures from one atmosphere to vacuum, with high thermal performance and light weight, is needed for cryogenically fueled space launch vehicles and aircraft. Multilayer insulation (MLI) performs well in a high vacuum, but the required vacuum shell for use in the atmosphere is heavy. Spray-on foam insulation (SOFI) is often used in these systems because of its light weight, but can have a higher heat flux than desired. We report on the continued development of Load Responsive Multilayer Insulation (LRMLI), an advanced thermal insulation system that uses dynamic beam discrete spacers that provide high thermal performance both in atmosphere and vacuum. LRMLI consists of layers of thermal radiation barriers separated and supported by micromolded polymer spacers. The spacers have low thermal conductance, and self-support a thin, lightweight vacuum shell that provides internal high vacuum in the insulation. The dynamic load responsive spacers compress to support the external load of a vacuum shell in one atmosphere, and decompress under reduced atmospheric pressure for lower heat leak. Structural load testing was performed on the spacers with various configurations. LRMLI was installed on a 400 liter tank and boil off testing with liquid nitrogen performed at various chamber pressures from one atmosphere to high vacuum. Testing was also performed with an MLI blanket on the outside of the LRMLI.

  18. Flexible III-V Multijunction Solar Blanket

    Microsoft Academic Search

    K. M. Edmondson; D. C. Law; G. Glenn; A. Paredes; R. R. King; N. H. Karam

    2006-01-01

    Thin high-efficiency triple junction GalnP\\/GaAs\\/Ge solar cells have been incorporated into prototype flexible blanket coupons with a coupon efficiency of 28% for AMO (0.1353 W\\/cm2) Prototype coupons have a specific power density from 360-500 W\\/kg and may well approach >1000 W\\/kg with further thin cell and blanket fabrication improvements. Initial LIV results are shown for a thin flexible three-cell and

  19. Fabrication and characterization of silica aerogel as synthetic tissues for medical imaging phantoms

    NASA Astrophysics Data System (ADS)

    In, Eunji; Naguib, Hani

    2015-05-01

    Medical imaging plays an important role in the field of healthcare industry both in clinical settings and in research and development. It is used in prevention, early detection of disease, in choosing the optimal treatment, during surgical interventions and monitoring of the treatment effects. Despite much advancement in the last few decades, rapid change on its technology development and variety of imaging parameters that differ with the manufacturer restrict its further development. Imaging phantom is a calibrating medium that is scanned or imaged in the field of medical imaging to evaluate, analyze and tune the performance of various imaging devices. A phantom used to evaluate an imaging device should respond in a similar manner to how human tissue and organs would act in that specific imaging modality. There has been many research on the phantom materials; however, there has been no attempt to study on the material that mimics the structure of lung or fibrous tissue. So with the need for development of gel with such structure, we tried to mimic this structure with aerogel. Silica aerogels have unique properties that include low density (0.003g/cm) and mesoporosity (pore size 2-50nm), with a high thermal insulation value (0.005W/mK) and high surface area (500-1200m-2/g).] In this study, we cross-linked with di-isocyanate, which is a group in polyurethane to covalently bond the polymer to the surface of silica aerogel to enhance the mechanical properties. By formation of covalent bonds, the structure can be reinforced by widening the interparticle necks while minimally reducing porosity.

  20. Thermal conductivity studies of a polyurea cross-linked silica aerogel-RTV 655 compound for cryogenic propellant tank applications in space

    NASA Astrophysics Data System (ADS)

    Sabri, F.; Marchetta, J.; Smith, K. M.

    2013-10-01

    Silica-based aerogel is an ideal thermal insulator with a makeup of up to 99% air associated with the highly porous nature of this material. Polyurea cross-linked silica aerogel (PCSA) has superior mechanical properties compared to the native aerogels yet retains the highly porous open pore network and functions as an ideal thermal insulator with added load-bearing capability necessary for some applications. Room temperature vulcanizing rubber-RTV 655—is a space qualified elastomeric thermal insulator and encapsulant with high radiation and temperature tolerance as well as chemical resistance. Storage and transport of cryogenic propellant liquids is an integral part of the success of future space exploratory missions and is an area under constant development. Limitations and shortcomings of current cryogenic tank materials and insulation techniques such as non-uniform insulation layers, self-pressurization, weight and durability issues of the materials used, has motivated the quest for alternative materials. Both RTV 655 and PCSA are promising space qualified materials with unique and tunable microscopic and macroscopic properties making them attractive candidates for this study. In this work, the effect of PCSA geometry and volume concentration on the thermal behavior of RTV 655—PCSA compound material has been investigated at room temperature and at a cryogenic temperature. Macroscopic and microscopic PCSA material was encapsulated at increasing concentrations in an RTV 655 elastomeric matrix. The effect of pulverization on the nanopores of PCSA as a method for creating large quantities of homogeneous PCSA microparticles has also been investigated and is reported. The PCSA volume concentrations ranged between 22% and 75% for both geometries. Thermal conductivity measurements were performed based on the steady state transient plane source method.

  1. Comparison of lithium and the eutectic lead lithium alloy, two candidate liquid metal breeder materials for self-cooled blankets

    SciTech Connect

    Malang, S. [Kernforschungszentrum Karlsruhe GmbH (Germany); Mattas, R. [Argonne National Lab., IL (United States)

    1994-06-01

    Liquid metals are attractive candidates for both near-term and long-term fusion applications. The subjects of this comparison are the differences between the two candidate liquid metal breeder materials Li and LiPb for use in breeding blankets in the areas of neutronics, magnetohydrodynamics, tritium control, compatibility with structural materials, heat extraction system, safety, and required R&D program. Both candidates appear to be promising for use in self-cooled breeding blankets which have inherent simplicity with the liquid metal serving as both breeders and coolant. The remaining feasibility question for both breeder materials is the electrical insulation between liquid metal and duct walls. Different ceramic coatings are required for the two breeders, and their crucial issues, namely self-healing of insulator cracks and radiation induced electrical degradation are not yet demonstrated. Each liquid metal breeder has advantages and concerns associated with it, and further development is needed to resolve these concerns.

  2. Radiation Insulation

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Apollo and subsequent spacecraft have had highly effective radiation barriers; made of aluminized polymer film, they bar or let in heat to maintain consistent temperatures inside. Tech 2000, formerly Quantum International Corporation used the NASA technology in its insulating materials, Super "Q" Radiant Barrier, for home, industry and mobile applications. The insulation combines industrial aluminum foil overlaid around a core of another material, usually propylene or mylar. The outer layer reflects up to 97 percent of heat; the central layer creates a thermal break in the structure and thus allows low radiant energy emission. The Quantum Cool Wall, used in cars and trucks, takes up little space while providing superior insulation, thus reducing spoilage and costs. The panels can also dampen sound and engine, exhaust and solar heat.

  3. Membranes Improve Insulation Efficiency 

    E-print Network

    Bullock, C. A.

    1986-01-01

    membranes over the insulation, and (2) layered membranes between fiber batts to form closed cells in the insulation both dramatically improve the efficiency of the fiber insulation. The efficiency of this insulation will be improved to an even greater degree...

  4. Insulation Material

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Manufactured by Hitco Materials Division of Armco, Inc. a ceramic fiber insulation material known as Refrasil has been used extensively as a heat-absorbing ablative reinforcement for such space systems as rocket motor nozzles, combustion chambers, and re-entry shields. Refrasil fibers are highly porous and do not melt or vaporize until fibers exceed 3,100 degrees Fahrenheit. Due to these and other properties, Refrasil has found utility in a number of industrial high temperature applications where glass, asbestos and other materials fail. Hitco used this insulation to assist Richardson Co., Inc. in the manufacturing of hard rubber and plastic molded battery cases.

  5. Design of Multilayer Insulation for the Multipurpose Hydrogen Test Bed

    NASA Technical Reports Server (NTRS)

    Marlow, Weston A.

    2011-01-01

    Multilayer insulation (MLI) is a critical component for future, long term space missions. These missions will require the storage of cryogenic fuels for extended periods of time with little to no boil-off and MLI is vital due to its exceptional radiation shielding properties. Several MLI test articles were designed and fabricated which explored methods of assembling and connecting blankets, yielding results for evaluation. Insight gained, along with previous design experience, will be used in the design of the replacement blanket for the Multipurpose Hydrogen Test Bed (MHTB), which is slated for upcoming tests. Future design considerations are discussed which include mechanical testing to determine robustness of such a system, as well as cryostat testing of samples to give insight to the loss of thermal performance of sewn panels in comparison to the highly efficient, albeit laborious application of the original MHTB blanket.

  6. Effects of overlaps, stitches, and patches on multilayer insulation.

    NASA Technical Reports Server (NTRS)

    Stimpson, L. D.; Jaworski, W.

    1972-01-01

    The effects of spacecraft installation-type discontinuities on aluminized Mylar multilayer insulation have been measured using an electrically heated cylindrical calorimeter. The experimental results have been reproducible within plus or minus 10% or better for identical blankets and less than plus or minus 5% for the same blanket. Good blanket performance can be obtained using short interleaving for joints, eliminating stitched seams, and using small patches, particularly over the hot side of stitches. The heat loss through stitching is excessive but highly localized. Analytical models matched to thermocouple test results are presented. The manner in which radiation and conduction participate in heat transfer adjacent to discontinuities is indicated. High lateral heat transfer is also established as an important phenomenon in the vicinity of a discontinuity.

  7. Summary report for ITER task - T68: MHD facility preparation for Li/V blanket option

    SciTech Connect

    Reed, C.B.; Haglund, R.C.; Miller, M.E. [and others

    1995-08-01

    A key feasibility issue for the ITER Vanadium/Lithium breeding blanket is the question of insulator coatings. Design calculations show that an electrically insulating layer is necessary to maintain an acceptably low MHD pressure drop. To enable experimental investigations of the MHD performance of candidate insulator materials and the technology for putting them in place, the room-temperature ALEX (Argonne`s Liquid Metal EXperiment) NaK facility was upgraded to a 300{degrees}C lithium system. The objective of this upgrade was to modify the existing facility to the minimum extent necessary, consistent with providing a safe, flexible, and easy to operate MHD test facility which uses lithium at ITER-relevant temperatures, Hartmann numbers, and interaction parameters. The facility was designed to produce MHD pressure drop data, test section voltage distributions, and heat transfer data for mid-scale test sections and blanket mockups. The system design description for this lithium upgrade of the ALEX facility is given in this document.

  8. Production and Rare Earth Doping of Aerogels

    NASA Astrophysics Data System (ADS)

    Montejo, Genderzon; Sanchez, Freddy; Wenzlau, Dylan; Hoffman, Kurt

    2010-10-01

    We present recent studies into several methods for making Aerogels. We used both critical point drying methods and chemical dehydroxylation to achieve low density glasses. We used an SEM to characterize the increased pore sizes in these glass materials. In addition, we will present preliminary results of our efforts to add rare earth ions to the glass structure. We are attempting to add the rare earth ions to the glass while avoiding the clustering problems normally encountered in the sol-gel synthesis technique.

  9. Macroscopic fluctuations theory of aerogel dynamics

    E-print Network

    Lefevere, Raphael; Zambotti, Lorenzo

    2010-01-01

    We consider extensive deterministic dynamics made of $N$ particles modeling aerogels under a macroscopic fluctuation theory description. By using a stochastic model describing those dynamics after a diffusive rescaling, we show that the functional giving the exponential decay in $N$ of the probability of observing a given energy and current profile is not strictly convex as a function of the current. This behaviour is caused by the fact that the energy current is carried by particles which may have arbitrary low speed with sufficiently large probability.

  10. Microsphere insulation systems

    NASA Technical Reports Server (NTRS)

    Allen, Mark S. (Inventor); Willen, Gary S. (Inventor); Mohling, Robert A. (Inventor)

    2005-01-01

    A new insulation system is provided that contains microspheres. This insulation system can be used to provide insulated panels and clamshells, and to insulate annular spaces around objects used to transfer, store, or transport cryogens and other temperature-sensitive materials. This insulation system provides better performance with reduced maintenance than current insulation systems.

  11. Flame Retardant Effect of Aerogel and Nanosilica on Engineered Polymers

    NASA Technical Reports Server (NTRS)

    Williams, Martha K.; Smith, Trent M.; Roberson, Luke B.; Yang, Feng; Nelson, Gordon L.

    2010-01-01

    Aerogels are typically manufactured vIa high temperature and pressure-critical-point drying of a colloidal metal oxide gel filled with solvents. Aerogel materials derived from silica materials represent a structural morphology (amorphous, open-celled nanofoams) rather than a particular chemical constituency. Aerogel is not like conventional foams in that it is a porous material with extreme microporosity and composed of individual features only a few nanometers in length with a highly porous dendriticlike structure. This unique substance has unusual properties such as low thermal conductivity, refractive index and sound suppression; in addition to its exceptional ability to capture fast moving dust. The highly porous nature of the aerogel's structure provides large amounts of surface area per unit weight. For instance, a silica aerogel material with a density of 100 kilograms per cubic meters can have surface areas of around 800 to 1500 square meters per gram depending on the precursors and process utilized to produce it. To take advantage of the unique properties of silica aerogels, especially the ultra light weight and low thermal conductivity, their composites with various engineering polymers were prepared and their flammability was investigated by Cone Calorimetry. The flammability of various polystyrene/silica aerogel nanocomposites were measured. The combination of these nanocomposites with a NASA patented flame retardant SINK were also studied. The results were compared with the base polymer to show the differences between composites with different forms of silica.

  12. Insulator coating for high temperature alloys method for producing insulator coating for high temperature alloys

    SciTech Connect

    Park, J.H.

    1994-12-31

    A method for fabricating an electrically insulating coating on a surface is disclosed comprising coating the surface with a metal, and reacting the metal coated surface with a nonmetal so as to create a film on the metal-coated surface. Alternatively, the invention provides for a method for producing a noncorrosive, electrically insulating coating on a surface saturated with a nonmetal comprising supplying a molten fluid, dissolving a metal in the molten fluid to create a mixture, and contacting the mixture with the saturated surface. Lastly, the invention provides an electrically insulative coating comprising an underlying structural substrate coated with an oxide or nitride compound. This invention has applications to breeding blankets for fusion reactors as well as to alkali metal thermal to electric converters.

  13. Insulation Material

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Apex Mills Corporation's superinsulators are used by makers of cold weather apparel, parkas, jackets, boots and outdoor gear such as sleeping bags. Their attraction in such applications is that radiant barrier insulation offers excellent warmth retention at minimal weight and bulk.

  14. A Cherenkov Radiation Detector with High Density Aerogels

    E-print Network

    Cremaldi, Lucien; Sonnek, Peter; Summers, Donald J; Reidy, Jim

    2009-01-01

    We have designed a threshold Cherenkov detector at the Rutherford-Appleton Laboratory to identify muons with momenta between 230 and 350 MeV/c. We investigated the properties of three aerogels for the design. The nominal indexes of refraction were n = 1.03, 1.07, 1.12, respectively. Two of the samples are of high density aerogel not commonly used for Cherenkov light detection. We present results of an examination of some optical properties of the aerogel samples and present basic test beam results.

  15. Highly porous and mechanically strong ceramic oxide aerogels

    NASA Technical Reports Server (NTRS)

    Leventis, Nicholas (Inventor); Meador, Mary Ann B. (Inventor); Johnston, James C. (Inventor); Fabrizio, Eve F. (Inventor); Ilhan, Ulvi F. (Inventor)

    2012-01-01

    Structurally stable and mechanically strong ceramic oxide aerogels are provided. The aerogels are cross-linked via organic polymer chains that are attached to and extend from surface-bound functional groups provided or present over the internal surfaces of a mesoporous ceramic oxide particle network via appropriate chemical reactions. The functional groups can be hydroxyl groups, which are native to ceramic oxides, or they can be non-hydroxyl functional groups that can be decorated over the internal surfaces of the ceramic oxide network. Methods of preparing such mechanically strong ceramic oxide aerogels also are provided.

  16. Highly porous and mechanically strong ceramic oxide aerogels

    NASA Technical Reports Server (NTRS)

    Leventis, Nicholas (Inventor); Meador, Mary Ann B. (Inventor); Johnston, James C. (Inventor); Fabrizio, Eve F. (Inventor); Ilhan, Ulvi F. (Inventor)

    2010-01-01

    Structurally stable and mechanically strong ceramic oxide aerogels are provided. The aerogels are cross-linked via organic polymer chains that are attached to and extend from surface-bound functional groups provided or present over the internal surfaces of a mesoporous ceramic oxide particle network via appropriate chemical reactions. The functional groups can be hydroxyl groups, which are native to ceramic oxides, or they can be non-hydroxyl functional groups that can be decorated over the internal surfaces of the ceramic oxide network. Methods of preparing such mechanically strong ceramic oxide aerogels also are provided.

  17. Temperature measurements of shocked silica aerogel foam

    NASA Astrophysics Data System (ADS)

    Falk, K.; McCoy, C. A.; Fryer, C. L.; Greeff, C. W.; Hungerford, A. L.; Montgomery, D. S.; Schmidt, D. W.; Sheppard, D. G.; Williams, J. R.; Boehly, T. R.; Benage, J. F.

    2014-09-01

    We present recent results of equation-of-state (EOS) measurements of shocked silica (SiO2) aerogel foam at the OMEGA laser facility. Silica aerogel is an important low-density pressure standard used in many high energy density experiments, including the novel technique of shock and release. Due to its many applications, it has been a heavily studied material and has a well-known Hugoniot curve. This work then complements the velocity and pressure measurements with additional temperature data providing the full EOS information within the warm dense matter regime for the temperature interval of 1-15 eV and shock velocities between 10 and 40 km/s corresponding to shock pressures of 0.3-2 Mbar. The experimental results were compared with hydrodynamic simulations and EOS models. We found that the measured temperature was systematically lower than suggested by theoretical calculations. Simulations provide a possible explanation that the emission measured by optical pyrometry comes from a radiative precursor rather than from the shock front, which could have important implications for such measurements.

  18. Multiscale Computer Simulation of Failure in Aerogels

    NASA Technical Reports Server (NTRS)

    Good, Brian S.

    2008-01-01

    Aerogels have been of interest to the aerospace community primarily for their thermal properties, notably their low thermal conductivities. While such gels are typically fragile, recent advances in the application of conformal polymer layers to these gels has made them potentially useful as lightweight structural materials as well. We have previously performed computer simulations of aerogel thermal conductivity and tensile and compressive failure, with results that are in qualitative, and sometimes quantitative, agreement with experiment. However, recent experiments in our laboratory suggest that gels having similar densities may exhibit substantially different properties. In this work, we extend our original diffusion limited cluster aggregation (DLCA) model for gel structure to incorporate additional variation in DLCA simulation parameters, with the aim of producing DLCA clusters of similar densities that nevertheless have different fractal dimension and secondary particle coordination. We perform particle statics simulations of gel strain on these clusters, and consider the effects of differing DLCA simulation conditions, and the resultant differences in fractal dimension and coordination, on gel strain properties.

  19. Analyses of Hubble Space Telescope Aluminized-Teflon Insulation Retrieved After 19 Years of Space Exposure

    NASA Technical Reports Server (NTRS)

    deGroh, Kim K.; Waters, Deborah L.; Mohammed, Jelila S.; Perry, Bruce A.; Banks, Bruce A.

    2012-01-01

    Since its launch in April 1990, the Hubble Space Telescope (HST) has made many important observations from its vantage point in low Earth orbit (LEO). However, as seen during five servicing missions, the outer layer of multilayer insulation (MLI) has become successively more embrittled and has cracked in many areas. In May 2009, during the 5th servicing mission (called SM4), two MLI blankets were replaced with new insulation pieces and the space-exposed MLI blankets were retrieved for degradation analyses by teams at NASA Glenn Research Center (GRC) and NASA Goddard Space Flight Center (GSFC). The MLI blankets were from Equipment Bay 8, which received direct sunlight, and Equipment Bay 5, which received grazing sunlight. Each blanket contained a range of unique regions based on environmental exposure and/or physical appearance. The retrieved MLI blanket s aluminized-Teflon (DuPont) fluorinated ethylene propylene (Al-FEP) outer layers have been analyzed for changes in optical, physical, and mechanical properties, along with space induced chemical and morphological changes. When compared to pristine material, the analyses have shown how the Al-FEP was severely affected by the space environment. This paper reviews tensile properties, solar absorptance, thermal emittance, x-ray photoelectron spectroscopy (XPS) data and atomic oxygen erosion values of the retrieved HST blankets after 19 years of space exposure.

  20. The conversion of a room temperature NaK loop to a high temperature MHD facility for Li/V blanket testing

    SciTech Connect

    Reed, C.B.; Haglund, R.C.; Miller, M.E.; Nasiatka, J.R. [Argonne National Lab., IL (United States); Kirillov, I.R.; Ogorodnikov, A.P.; Preslitski, G.V.; Goloubovitch, G.P. [Efremov (D.V.) Research Inst. of Electrophysical Apparatus, St. Petersburg (Russian Federation); Xu, Zeng Yu [Southwestern Inst. of Physics (China). Fusion Technology and Materials Div.

    1996-12-31

    The Vanadium/Lithium system has been the recent focus of ANL`s Blanket Technology Pro-ram, and for the last several years, ANL`s Liquid Metal Blanket activities have been carried out in direct support of the ITER (International Thermonuclear Experimental Reactor) breeding blanket task area. A key feasibility issue for the ITER Vanadium/Lithium breeding blanket is the Near the development of insulator coatings. Design calculations, Hua and Gohar, show that an electrically insulating layer is necessary to maintain an acceptably low magneto-hydrodynamic (MHD) pressure drop in the current ITER design. Consequently, the decision was made to convert Argonne`s Liquid Metal EXperiment (ALEX) from a 200{degrees}C NaK facility to a 350{degrees}C lithium facility. The upgraded facility was designed to produce MHD pressure drop data, test section voltage distributions, and heat transfer data for mid-scale test sections and blanket mockups at Hartmann numbers (M) and interaction parameters (N) in the range of 10{sup 3} to 10{sup 5} in lithium at 350{degrees}C. Following completion of the upgrade work, a short performance test was conducted, followed by two longer multiple-hour, MHD tests, all at 230{degrees}C. The modified ALEX facility performed up to expectations in the testing. MHD pressure drop and test section voltage distributions were collected at Hartmann numbers of 1000.

  1. The requirements for processing tritium recovered from liquid lithium blankets: The blanket interface

    SciTech Connect

    Clemmer, R.G.; Finn, P.A.; Greenwood, L.R.; Grimm, T.L.; Sze, D.K.; Bartlit, J.R.; Anderson, J.L.; Yoshida, H.; Naruse

    1988-03-01

    We have initiated a study to define a blanket processing mockup for Tritium Systems Test Assembly. Initial evaluation of the requirements of the blanket processing system have been started. The first step of the work is to define the condition of the gaseous tritium stream from the blanket tritium recovery system. This report summarizes this part of the work for one particular blanket concept, i.e., a self-cooled lithium blanket. The total gas throughput, the hydrogen to tritium ratio, the corrosive chemicals, and the radionuclides are defined. The key discoveries are: the throughput of the blanket gas stream (including the helium carrier gas) is about two orders of magnitude higher than the plasma exhaust stream;the protium to tritium ratio is about 1, the deuterium to tritium ratio is about 0.003;the corrosion chemicals are dominated by halides;the radionuclides are dominated by C-14, P-32, and S-35;their is high level of nitrogen contamination in the blanket stream. 77 refs., 6 figs., 13 tabs.

  2. Evaluation of the parfait blanket concept for fast breeder reactors

    E-print Network

    Ducat, Glenn Alexander

    1974-01-01

    An evaluation of the neutronic, thermal-hydraulic, mechanical and economic characteristics of fast breeder reactor configurations containing an internal blanket has been performed. This design, called the parfait blanket ...

  3. Electromagnetically Restrained Lithium Blanket APEX Interim Report November, 1999

    E-print Network

    California at Los Angeles, University of

    to avoid corrosion or fire. Lithium's high electrical conductivity may possibly permit efficient, compactElectromagnetically Restrained Lithium Blanket APEX Interim Report November, 1999 6-1 CHAPTER 6: ELECTROMAGNETICALLY RESTRAINED LITHIUM BLANKET Contributors Robert Woolley #12;Electromagnetically Restrained Lithium

  4. Neutronic implications of lead-lithium blankets

    SciTech Connect

    Meier, W.R.

    1982-08-01

    Lead-lithium alloys have been proposed for use in several conceptual blanket designs for both inertial and magnetic confinement fusion reactors. In most cases, Pb/sub 83/Li/sub 17/, a eutectic with a melting point of 235/sup 0/C, is the chosen composition. The primary reasons for using Pb/sub 83/Li/sub 17/ instead of Li as the tritium breeding material are the perceived safety advantages, low tritium solubility, and favorable neutronic characteristics. This paper describes the neutronic characteristics of Pb/sub 83/Li/sub 17/ blankets with emphasis on the enhanced neutron leakage through chamber ports and the degradation in blanket performance parameters that occurs as a result of the enhanced leakage.

  5. Window Insulation

    NASA Technical Reports Server (NTRS)

    1979-01-01

    A highly reflective insulating material developed to protect NASA spacecraft from intense solar radiation is now being used in a commercially-available window-insulating product which offers significant energy savings. Called Nunsun, it is a thin metallized film adhesively bonded to windows of homes, office buildings, schools, industrial plants and other facilities; the film reflects the sun's heat and glare outward, thereby cutting down on energy costs for cooling. Trained dealer personnel can affix the film to windows of any size in minutes (right), converting ordinary glass to heat-reflective mirror glass at a fraction of the cost. Manufactured by National Metallizing, a division of Standard Packaging Corporation, Cranbury, New Jersey, Nunsun is also available in windowshade form.

  6. Helium and Neon in "Blank" Stardust Aerogel Samples

    NASA Astrophysics Data System (ADS)

    Palma, R. L.; Pepin, R. O.; Westphal, A.; Schlutter, D.; Gainsforth, Z.

    2012-03-01

    Helium and neon concentrations and compositions were measured in 49 samples of "blank" aerogel from Stardust cell C2044. Five samples show interesting compositions that if related to the Track 41 impactor indicate a complicated parent particle.

  7. Partially hydrolized alkoxysilanes as precursors for silica aerogels

    SciTech Connect

    Tillotson, T.M.; Hrubesh, L.W.; Thomas, I.M.

    1988-03-31

    The classical sol-gel process for synthesizing SiO/sub 2/ aerogels involves the hydrolysiscondensation of tetraethyoxysilane (TEOS) andor teramethyoxysilane (TMOS) to produce a gel which can then be supercritically extracted to a low density, highly porous aerogel glass. Controlled hydrolysis of TEOS and TMOS leads to partially hydrolyzed compounds that can be subsequently water processed to form silica aerogels in the density range from .020 to .500 gcc. The partially hydrolyzed compounds are stable when sealed from moist air and can be stored for future use. We discuss the controlled conditions used to obtain these compounds and present data that characterize their structure. We detail the procedures for preparing the wide range of aerogel densities. We also report on their use as an adhesive. 4 refs., 5 figs.

  8. Aerogel Antennas Communications Study Using Error Vector Magnitude Measurements

    NASA Technical Reports Server (NTRS)

    Miranda, Felix A.; Mueller, Carl H.; Meador, Mary Ann B.

    2014-01-01

    This presentation discusses an aerogel antennas communication study using error vector magnitude (EVM) measurements. The study was performed using 2x4 element polyimide (PI) aerogel-based phased arrays designed for operation at 5 GHz as transmit (Tx) and receive (Rx) antennas separated by a line of sight (LOS) distance of 8.5 meters. The results of the EVM measurements demonstrate that polyimide aerogel antennas work appropriately to support digital communication links with typically used modulation schemes such as QPSK and 4 DQPSK. As such, PI aerogel antennas with higher gain, larger bandwidth and lower mass than typically used microwave laminates could be suitable to enable aerospace-to- ground communication links with enough channel capacity to support voice, data and video links from CubeSats, unmanned air vehicles (UAV), and commercial aircraft.

  9. Aerogel Antennas Communications Study Using Error Vector Magnitude Measurements

    NASA Technical Reports Server (NTRS)

    Miranda, Felix A.; Mueller, Carl H.; Meador, Mary Ann B.

    2014-01-01

    This paper discusses an aerogel antennas communication study using error vector magnitude (EVM) measurements. The study was performed using 4x2 element polyimide (PI) aerogel-based phased arrays designed for operation at 5 GHz as transmit (Tx) and receive (Rx) antennas separated by a line of sight (LOS) distance of 8.5 meters. The results of the EVM measurements demonstrate that polyimide aerogel antennas work appropriately to support digital communication links with typically used modulation schemes such as QPSK and pi/4 DQPSK. As such, PI aerogel antennas with higher gain, larger bandwidth and lower mass than typically used microwave laminates could be suitable to enable aerospace-to-ground communication links with enough channel capacity to support voice, data and video links from cubesats, unmanned air vehicles (UAV), and commercial aircraft.

  10. SEAL Studies of Variant Blanket Concepts and Materials

    Microsoft Academic Search

    I. Cook; N. P. Taylor; C. B. A. Forty; W. E. Han

    1997-01-01

    Within the European SEAL (Safety and Environmental Assessment of fusion power, Long-term) program, safety and environmental assessments have been performed which extend the results of the earlier SEAFP (Safety and Environmental Assessment of Fusion Power) program to a wider range of blanket designs and material choices. The four blanket designs analysed were those which had been developed within the Blanket

  11. Breeding blanket concepts for fusion and materials requirements

    E-print Network

    Raffray, A. René

    Breeding blanket concepts for fusion and materials requirements A.R. Raffray a,*, M. Akiba b , V of recent breeding blanket concepts and identifies the key material issues associated with them A variety of breeding blanket concepts has been considered, ranging from more conservative concepts

  12. Breeding Blanket Concepts for Fusion and Materials Requirements

    E-print Network

    Raffray, A. René

    1 Breeding Blanket Concepts for Fusion and Materials Requirements A. R. Raffray1, M. Akiba2, V;2 Outline of Presentation · Highlight key performance and attractiveness parameters for breeding blanket ­ Simplicity · Tritium ­ Need for tritium self-sufficiency from blanket tritium breeding ­ Total tritium

  13. A tour-de-force in polymer crosslinked aerogels

    NASA Astrophysics Data System (ADS)

    Mulik, Sudhir M.

    In the quest of building mechanically strong materials with low density and high porosity, polymer crosslinked aerogels stand as the most promising nano-engineered examples. Covalent attachment of polymers and bridging of skeletal nanoparticles of typical aerogels is demonstrated by using surface initiated polymerization (SIP) with a bidentate free-radical initiator structurally related to azobisisobutyronitrile (AIBN) and confined on mesoporous silica surfaces. Different monomers were introduced in the mesopores and upon heating at 70 °C, all mesoporous surfaces throughout the entire skeletal framework were coated conformally with a 10-12 nm thick polymer layer indistinguishable spectroscopically from the respective commercial bulk materials. The new materials combine hydrophobicity with vastly improved mechanical properties. Resorcinol formaldehyde (RF) aerogels are pursued as precursors of carbon aerogels, which are electrically conducting. We have developed a HCl-catalyzed gelation process in CH3CN, which is completed in ˜ 2 h at room temperature as opposed to the week-long base-catalyzed literature process. The final aerogels are spectroscopically indistinguishable from typical base-catalyzed samples. Carbon (C-) aerogels are made by pyrolysis of RF aerogels, and combine electrical conductivity with a high open mesoporosity. Nevertheless, macropores facilitate mass-transfer and they could be beneficial for applications in separations or as fuel cell and battery electrodes. Here, we report a method where an open macroporosity is introduced by pyrolysing RF aerogels whose skeletal nanoparticles have been coated conformally and crosslinked chemically with an isocyanate-derived polymer. The new macroporous material was evaluated electrochemically for possible application as an electrode in batteries and fuel cells.

  14. A RICH with aerogel: a study of refractive index uniformity

    E-print Network

    Alemi, M; Calvi, M; Matteuzzi, C; Musy, M; Perego, D L; Easo, S

    2004-01-01

    The use of aerogel as a radiator in the RICH detectors of LHCb is a challenge due to the hot environment of the hadron collider LHC. Large size tiles of silica aerogel were recently produced with unprecedented optical quality for such dimensions. Results of laboratory measurements and beam tests are briefly reported. A description of a method to measure the uniformity of the index of refraction within the tile is given.

  15. Electron Beam Diagnostics using Coherent Cherenkov Radiation in Aerogel

    SciTech Connect

    Tikhoplav, R.; Knyazik, A.; Rosenzweig, J. B. [UCLA Physics Dept., Los Angeles, CA 90066 (United States); Ruelas, M. [RadiaBeam Technologies, Marina Del Ray, CA 90292 (United States)

    2009-01-22

    The use of coherent Cherenkov radiation as a diagnostic tool for longitudinal distribution of an electron beam is studied in this paper. Coherent Cherenkov radiation is produced in an aerogel with an index of refraction close to unity. An aerogel spectral properties are experimentally studied and analyzed. This method will be employed for the helical IFEL bunching experiment at Neptune linear accelerator facility at UCLA.

  16. Minimum thermal conductivity considerations in aerogel thin films

    NASA Astrophysics Data System (ADS)

    Hopkins, Patrick E.; Kaehr, Bryan; Piekos, Edward S.; Dunphy, Darren; Jeffrey Brinker, C.

    2012-06-01

    We demonstrate the use time domain thermoreflectance (TDTR) to measure the thermal conductivity of the solid silica network of aerogel thin-films. TDTR presents a unique experimental capability for measuring the thermal conductivity of porous media due to the nanosecond time domain aspect of the measurement. In short, TDTR is capable of explicitly measuring the change in temperature with time of the solid portion of porous media independently from the pores or effective media. This makes TDTR ideal for determining the thermal transport through the solid network of the aerogel film. We measure the thermal conductivity of the solid silica networks of an aerogel film that is 10% solid, and the thermal conductivity of the same type of film that has been calcined to remove the terminating methyl groups. We find that for similar densities, the thermal conductivity through the silica in the aerogel thin films is similar to that of bulk aerogels. We theoretically describe the thermal transport in the aerogel films with a modified minimum limit to thermal conductivity that accounts for porosity through a reduction in phonon velocity. Our porous minimum limit agrees well with a wide range of experimental data in addition to sound agreement with differential effective medium theory. This porous minimum limit therefore demonstrates an approach to predict the thermal conductivity of porous disordered materials with no a priori knowledge of the corresponding bulk phase, unlike differential effective medium theory.

  17. Silica aerogel: An intrinsically low dielectric constant material

    SciTech Connect

    Hrubesh, L.W.

    1995-04-01

    Silica aerogels are highly porous solids having unique morphologies in wavelength of visible which both the pores and particles have sizes less than the wavelength of visible light. This fine nanostructure modifies the normal transport mechanisms within aerogels and endows them with a variety of exceptional physical properties. For example, aerogels have the lowest measured thermal conductivity and dielectric constant for any solid material. The intrinsically low dielectric properties of silica aerogels are the direct result of the extremely high achievable porosities, which are controllable over a range from 75% to more than 99.8 %, and which result in measured dielectric constants from 2.0 to less than 1.01. This paper discusses the synthesis of silica aerogels, processing them as thin films, and characterizing their dielectric properties. Existing data and other physical characteristics of bulk aerogels (e.g., thermal stablity, thermal expansion, moisture adsorption, modulus, dielectric strength, etc.), which are useful for evaluating them as potential dielectrics for microelectronics, are also given.

  18. Comparative study on pore structures of mesoporous ZSM-5 from resorcinol-formaldehyde aerogel and carbon aerogel templating.

    PubMed

    Tao, Yousheng; Hattori, Yoshiyuki; Matumoto, Akihiko; Kanoh, Hirofumi; Kaneko, Katsumi

    2005-01-13

    Resorcinol-formaldehyde aerogels and carbon aerogels of different mesoporosities have been used as templates for preparing bimodal zeolites of mesopores. Samples were thoroughly characterized with X-ray diffraction, field emission scanning electron microscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, N(2) adsorption at 77 K, as well as FT-IR spectroscopy and (29)Si nuclear magnetic resonance spectroscopy. The mesoporous ZSM-5 zeolites have additional mesopores of 9-25 nm in widths and 0.07-0.2 cm(3)/g in volumes, besides their perfect inherent micropores. Experimental results show the mesoporous systems of the finally obtained zeolites can be influenced by proper preparation of resorcinol-formaldehyde aerogels and carbon aerogels through solution chemistry. Consequently, zeolites of tunable mesoporosities can be prepared with this unique methodology. PMID:16851004

  19. Silica-Aerogel Composites Opacified with La(0.7)Sr(0.3)MnO3

    NASA Technical Reports Server (NTRS)

    Rhine, Wendell; Polli, Andrew; Deshpande, Kiranmayi

    2009-01-01

    As part of an effort to develop improved lightweight thermal-insulation tiles to withstand temperatures up to 1,000 C, silica aerogel/fused-quartz-fiber composite materials containing La0.7Sr0.3MnO3 particles as opacifiers have been investigated as potentially offering thermal conductivities lower than those of the otherwise equivalent silica-aerogel composite materials not containing La(0.7)Sr(0.3)MnO3 particles. The basic idea of incorporating opacifying particles into silica-aerogels composite to reduce infrared radiative contributions to thermal conductivities at high temperatures is not new: it has been reported in a number of previous NASA Tech Briefs articles. What is new here is the selection of La(0.7)Sr(0.3)MnO3 particles as candidate opacifiers that, in comparison with some prior opacifiers (carbon black and metal nanoparticles), are more thermally stable. The preparation of a composite material of the present type includes synthesis of the silica-aerogel component in a sol-gel process. The La(0.7)Sr(0.3)MnO3 particles, made previously in a separate process, are mixed into the sol, which is then cast onto fused-quartz-fiber batting. Then the aerogel-casting solution is poured into the mold, where it permeates the silica fiber felt. After the sol has gelled, the casting is aged and then subjected to supercritical drying to convert the gel to the final aerogel form. The separate process for making the La(0.7)Sr(0.3)MnO3 particles begins with the slow addition of corresponding proportions of La(CH3COOH)3, Mn(CH3COOH)3, and Sr(NO3)2 to a solution of H2O2 in H2O. The solution is then peptized by drop-wise addition of NH4OH to obtain a sol. Next, the sol is dried in an oven at a temperature of 120 C to obtain a glassy solid. The solid is calcined at 700 C to convert it to La(0.7)Sr(0.3)MnO3. Then La(0.7)Sr(0.3)MnO3 particles are made by ball-milling the calcined solid. The effectiveness of La(0.7)Sr(0.3)MnO3 particles as opacifiers and thermal-conductivity reducers depends on the statistical distribution of particle sizes as well as the relative proportions of La(0.7)Sr(0.3)MnO3 and aerogel. For experiments performed thus far, samples of aerogel/fiber composites were formulated to have, variously, silica target density of 0.07 or 0.14 g/cu cm and to contain 30 percent of La(0.7)Sr(0.3)MnO3 in average particle size of 0.3 or 3 microns. The thermal conductivities of the samples containing the 3 micron La(0.7)Sr(0.3)MnO3 particles were found to be lower than those of the samples containing the 0.3 micron La(0.7)Sr(0.3)MnO3 particles. The optimum particle size is believed to be between 1 and 5 microns.

  20. Composite thermal insulator

    Microsoft Academic Search

    Sh. Ishihara; R. Yamamoto; H. Yoneno

    1985-01-01

    The disclosure is directed to a composite thermal insulator including a Freon gas expanded plastic, and an evacuated powder insulation. The present invention provides a composite thermal insulator light in weight and having a superior heat insulating performance over a long period through replacement of a thick metallic container conventionally used for the evacuated powder insulation and considered indispensable for

  1. Parametric Weight Comparison of Advanced Metallic, Ceramic Tile, and Ceramic Blanket Thermal Protection Systems

    NASA Technical Reports Server (NTRS)

    Myers, David E.; Martin, Carl J.; Blosser, Max L.

    2000-01-01

    A parametric weight assessment of advanced metallic panel, ceramic blanket, and ceramic tile thermal protection systems (TPS) was conducted using an implicit, one-dimensional (I-D) finite element sizing code. This sizing code contained models to account for coatings fasteners, adhesives, and strain isolation pads. Atmospheric entry heating profiles for two vehicles, the Access to Space (ATS) vehicle and a proposed Reusable Launch Vehicle (RLV), were used to ensure that the trends were not unique to a certain trajectory. Ten TPS concepts were compared for a range of applied heat loads and substructural heat capacities to identify general trends. This study found the blanket TPS concepts have the lightest weights over the majority of their applicable ranges, and current technology ceramic tiles and metallic TPS concepts have similar weights. A proposed, state-of-the-art metallic system which uses a higher temperature alloy and efficient multilayer insulation was predicted to be significantly lighter than the ceramic tile stems and approaches blanket TPS weights for higher integrated heat loads.

  2. INTOR first wall/blanket/shield activity

    SciTech Connect

    Gohar, Y.; Billone, M.C.; Cha, Y.S.; Finn, P.A.; Hassanein, A.M.; Liu, Y.Y.; Majumdar, S.; Picologlou, B.F.; Smith, D.L.

    1986-01-01

    The main emphasis of the INTOR first wall/blanket/shield (FWBS) during this period has been upon the tritium breeding issues. The objective is to develop a FWBS concept which produces the tritium requirement for INTOR operation and uses a small fraction of the first wall surface area. The FWBS is constrained by the dimensions of the reference design and the protection criteria required for different reactor components. The blanket extrapolation to commercial power reactor conditions and the proper temperature for power extraction have been sacrificed to achieve the highest possible local tritium breeding ratio (TBR). In addition, several other factors that have been considered in the blanket survey study include safety, reliability, lifetime fluence, number of burn cycles, simplicity, cost, and development issues. The implications of different tritium supply scenarios were discussed from the cost and availability for INTOR conditions. A wide variety of blanket options was explored in a preliminary way to determine feasibility and to see if they can satisfy the INTOR conditions. This survey and related issues are summarized in this report. Also discussed are material design requirements, thermal hydraulic considerations, structure analyses, tritium permeation through the first wall into the coolant, and tritium inventory.

  3. Disinfection of hospital blankets with synthetic phenolic compounds

    PubMed Central

    Larkin, I. M.; Bridson, E. Y.; Grieve, W. S. M.; Gibson, J. W.

    1961-01-01

    A cheap method by which hospital blankets may be effectively disinfected (approximately 3d. per blanket) is described. A recommendation is made that blankets from the patients' beds be divided into: `socially dirty' blankets to be laundered, possibly at infrequent intervals; and `socially clean' blankets to be disinfected frequently. The wide range of a synthetic phenolic compound is described. This substance is effective against all the common pathogenic bacteria in the presence of organic matter, anionic, or cationic detergents. Details are given of laboratory trials with this method of disinfection and of pilot trials at the Group hospital laundry. The recommended method is simpler and takes less time than ordinary washing. PMID:13759121

  4. Pipe Insulation Economies 

    E-print Network

    Schilling, R. E.

    1986-01-01

    Pipe Insulation Economies is a computer program written in IBM basic to simplify the economic insulation thickness for an insulated pipe. Many articles have been written on this subject, from simple nomographs to a small book written in 1976...

  5. Water-cooled solid-breeder blanket concept for ITER

    SciTech Connect

    Gohar, Y.; Baker, C.C.; Attaya, H.; Billone, M.; Clemmer, R.C.; Finn, P.A.; Hassanein, A.; Johnson, C.E.; Majumdar, S.; Mattas, R.F.

    1989-03-01

    A water cooled solid-breeder blanket concept was developed for ITER. The main function of this blanket is to produce the necessary tritium for the ITER operation. Several design features are incorporated in this blanket concept to increase its attractiveness. The main features are the following: (a) a multilayer concept which reduces fabrication cost; (b) a simple blanket configuration which results in reliability advantages; (c) a very small breeder volume is employed to reduce the tritium inventory and the blanket cost; (d) a high tritium breeding ratio eliminates the need for an outside tritium supply; (e) a low-pressure system decreases the required steel fraction for structural purposes; (f) a low-temperature operation reduces the swelling concerns for beryllium; and (g) the small fractions of structure and breeder materials used in the blanket reduce the decay heat source. The key features and design analyses of this blanket are summarized in this paper.

  6. Topological insulators/Isolants topologiques An introduction to topological insulators

    E-print Network

    Paris-Sud XI, Université de

    Topological insulators/Isolants topologiques An introduction to topological insulators Introduction topology, the insulator is called a topological insulator. We introduce this notion of topological order sont finalement discutées. Keywords: topological insulator, topological band theory, quantum anomalous

  7. Sensitivity of dual-wall structures under hypervelocity impact to multi-layer thermal insulation thickness and placement

    NASA Technical Reports Server (NTRS)

    Schonberg, William P.

    1993-01-01

    Results are presented from an experimental study in which Al dual-wall structures were tested, under various high-speed impact conditions, with a view to the effect of multilayer insulation thickness and location on perforation resistance. Attention is given to comparisons of the damage sustained by dual-wall systems with multilayer insulation blankets of various thicknesses and at various locations within the dual-wall system, under comparable impact loading conditions. The placement of the insulation has a significant effect on the ballistic limit of the dual-wall structures considered, while reducing insulation thickness by as much as a third did not.

  8. Compression Testing of Alumina Fiber Insulation

    NASA Technical Reports Server (NTRS)

    Vaughn, Wallace L.

    2006-01-01

    A series of tests were conducted to measure the response of alumina fiber insulation to compression loading. The alumina fiber insulation is a candidate gasket material for the Space Shuttle Government Furnished Equipment (GFE) Tile Overlay Repair. Tests were conducted at room temperature and 2300 F. The alumina fiber insulation is a fibrous insulation blanket which was supplied to Langley in two forms, a nominal 3 lb/ft3 version and a nominal 9 lb/ft3 version. The 3 lb/ft3 material was tested as sheets 0.15 and 0.25 inches thick and the 9 lb/ft3 material in sheets 1 inch thick. The material showed very non-linear compression behavior with the compressive resistance of the material increasing as the material was compressed. The 3 lb/ft3 0.15-inch thick material required 4.1 psi to reach the nominal installation thickness of 0.045 inches and retain a load of 2.1 lbs during unloading. Testing at 2300 F resulted in a stiffer more board-like material. The 3 lb/ft3 0.15-inch thick material retained 1 psi of compressive resistance after a 10 minute hold at 2300 F and 0.045 inches thickness.

  9. Tank Insulation

    NASA Technical Reports Server (NTRS)

    1979-01-01

    For NASA's Apollo program, McDonnell Douglas Astronautics Company, Huntington Beach, California, developed and built the S-IVB, uppermost stage of the three-stage Saturn V moonbooster. An important part of the development task was fabrication of a tank to contain liquid hydrogen fuel for the stage's rocket engine. The liquid hydrogen had to be contained at the supercold temperature of 423 degrees below zero Fahrenheit. The tank had to be perfectly insulated to keep engine or solar heat from reaching the fuel; if the hydrogen were permitted to warm up, it would have boiled off, or converted to gaseous form, reducing the amount of fuel available to the engine. McDonnell Douglas' answer was a supereffective insulation called 3D, which consisted of a one-inch thickness of polyurethane foam reinforced in three dimensions with fiberglass threads. Over a 13-year development and construction period, the company built 30 tanks and never experienced a failure. Now, after years of additional development, an advanced version of 3D is finding application as part of a containment system for transporting Liquefied Natural Gas (LNG) by ship.

  10. Aerogel as a Sample Collector and Sample Mount for Transmission XRD Analysis

    NASA Technical Reports Server (NTRS)

    Bish, D. L.; Vaniman, D. T.; Chipera, S. J.; Yen, A. S.; Jones, S. M.

    2001-01-01

    Silica aerogel can be used for dust collection and in situ X-ray analysis. Aerogels can be less absorbing than Be, and it is feasible to obtain X-ray transmission factors >50% using typical aerogels together with a 100-micrometer Be backing foil. Additional information is contained in the original extended abstract.

  11. Insulation Coordination for Gas Insulated Substations

    Microsoft Academic Search

    Helfried Anderl; Charles Wagner; Thomas Dodds

    1973-01-01

    This paper presents the development of BIL (Basic Lightning Impulse Insulation Level) ratings for SF6 gas insulated substations from 72.5 kV to 765 kV. The unique properties of the gas insulated substation are analyzed and insulation coordination design techniques are utilized to determine BIL ratings for the substation equipment, other than the transformer, with a lightning arrester located at the

  12. Noble metal aerogels-synthesis, characterization, and application as electrocatalysts.

    PubMed

    Liu, Wei; Herrmann, Anne-Kristin; Bigall, Nadja C; Rodriguez, Paramaconi; Wen, Dan; Oezaslan, Mehtap; Schmidt, Thomas J; Gaponik, Nikolai; Eychmüller, Alexander

    2015-02-17

    CONSPECTUS: Metallic and catalytically active materials with high surface area and large porosity are a long-desired goal in both industry and academia. In this Account, we summarize the strategies for making a variety of self-supported noble metal aerogels consisting of extended metal backbone nanonetworks. We discuss their outstanding physical and chemical properties, including their three-dimensional network structure, the simple control over their composition, their large specific surface area, and their hierarchical porosity. Additionally, we show some initial results on their excellent performance as electrocatalysts combining both high catalytic activity and high durability for fuel cell reactions such as ethanol oxidation and the oxygen reduction reaction (ORR). Finally, we give some hints on the future challenges in the research area of metal aerogels. We believe that metal aerogels are a new, promising class of electrocatalysts for polymer electrolyte fuel cells (PEFCs) and will also open great opportunities for other electrochemical energy systems, catalysis, and sensors. The commercialization of PEFCs encounters three critical obstacles, viz., high cost, insufficient activity, and inadequate long-term durability. Besides others, the sluggish kinetics of the ORR and alcohol oxidation and insufficient catalyst stability are important reasons for these obstacles. Various approaches have been taken to overcome these obstacles, e.g., by controlling the catalyst particle size in an optimized range, forming multimetallic catalysts, controlling the surface compositions, shaping the catalysts into nanocrystals, and designing supportless catalysts with extended surfaces such as nanostructured thin films, nanotubes, and porous nanostructures. These efforts have produced plenty of excellent electrocatalysts, but the development of multisynergetic functional catalysts exhibiting low cost, high activity, and high durability still faces great challenges. In this Account, we demonstrate that the sol-gel process represents a powerful "bottom-up" strategy for creating nanostructured materials that tackles the problems mentioned above. Aerogels are unique solid materials with ultralow densities, large open pores, and ultimately high inner surface areas. They magnify the specific properties of nanomaterials to the macroscale via self-assembly, which endow them with superior properties. Despite numerous investigations of metal oxide aerogels, the investigation of metal aerogels is in the early stage. Recently, aerogels including Fe, Co, Ni, Sn, and Cu have been obtained by nanosmelting of hybrid polymer-metal oxide aerogels. We report here exclusively on mono-, bi- and multimetallic noble metal aerogels consisting of Ag, Au, Pt, and Pd and their application as electrocatalysts. PMID:25611348

  13. Dielectric and other properties of polyimide aerogels containing fluorinated blocks.

    PubMed

    Meador, Mary Ann B; McMillon, Emily; Sandberg, Anna; Barrios, Elizabeth; Wilmoth, Nathan G; Mueller, Carl H; Miranda, Félix A

    2014-05-14

    The dielectric and other properties of a series of low-density polyimide block copolymer aerogels have been characterized. Two different anhydride-capped polyimide oligomers were synthesized: one from 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and 4,4'-oxidianiline (ODA) and the other from biphenyl-3,3',4,4'-tetracarboxylic dianhydride and ODA. The oligomers were combined with 1,3,5-triaminophenoxybenzene to form a block copolymer networked structure that gelled in under 1 h. The polyimide gels were supercritically dried to give aerogels with relative dielectric constants as low as 1.08. Increasing the amount of 6FDA blocks by up to 50% of the total dianhydride decreased the density of the aerogels, presumably by increasing the free volume and also by decreasing the amount of shrinkage seen upon processing, resulting in a concomitant decrease in the dielectric properties. In this study, we have also altered the density independent of fluorine substitution by changing the polymer concentration in the gelation reactions and showed that the change in dielectric due to density is the same with and without fluorine substitution. The aerogels with the lowest dielectric properties and lowest densities still had compressive moduli of 4-8 MPa (40 times higher than silica aerogels at the same density), making them suitable as low dielectric substrates for lightweight antennas for aeronautic and space applications. PMID:24483208

  14. Progress on the TAURO blanket system

    Microsoft Academic Search

    H Golfier; G Aiello; M Futterer; L Giancarli; A Li-Puma; Y Poitevin; J Szczepanski

    2002-01-01

    TAURO is a self-cooled Pb?17Li blanket for Fusion Power Reactors (FPRs) using SiCf\\/SiC composites structures. It has been developed with the objective to achieve both passive safety and high thermal efficiency. The Pb?17Li outlet temperature exceeds 850°C. A Brayton cycle is envisaged for power conversion and the possibility of hydrogen production is addressed. This paper recalls the main features of

  15. Calcium silicate insulation structure

    DOEpatents

    Kollie, Thomas G. (Oak Ridge, TN); Lauf, Robert J. (Oak Ridge, TN)

    1995-01-01

    An insulative structure including a powder-filled evacuated casing utilizes a quantity of finely divided synthetic calcium silicate having a relatively high surface area. The resultant structure-provides superior thermal insulating characteristics over a broad temperature range and is particularly well-suited as a panel for a refrigerator or freezer or the insulative barrier for a cooler or a insulated bottle.

  16. Properties of cryogenic insulants

    Microsoft Academic Search

    J. Gerhold

    1998-01-01

    High vacuum, cold gases and liquids, and solids are the principal insulating materials for superconducting apparatus. All these insulants have been claimed to show fairly good intrinsic dielectric performance under laboratory conditions where small scale experiments in the short term range are typical. However, the insulants must be integrated into large scaled insulating systems which must withstand any particular stressing

  17. Insulation Materials Investigation

    NSDL National Science Digital Library

    2014-09-18

    Students test the insulation properties of different materials by timing how long it takes ice cubes to melt in the presence of various insulating materials. Students learn about the role that thermal insulation materials can play in reducing heat transfer by conduction, convection and radiation, as well as the design and implementation of insulating materials in construction and engineering.

  18. Deposition of ruthenium nanoparticles on carbon aerogels for high energy density supercapacitor electrodes

    SciTech Connect

    Miller, J.M.; Dunn, B. [Univ. of California, Los Angeles, CA (United States). Dept. of Materials Science and Engineering; Tran, T.D.; Pekala, R.W. [Lawrence Livermore National Labs., CA (United States). Chemical Sciences Div.

    1997-12-01

    The preparation and characterization of high surface area ruthenium/carbon aerogel composite electrodes for use in electrochemical capacitors is reported. These new materials have been prepared by the chemical vapor impregnation of ruthenium into carbon aerogels to produce a uniform distribution of adherent {approx}20 {angstrom} nanoparticles on the aerogel surface. The electrochemically oxidized ruthenium particles contribute a pseudocapacitance to the electrode and dramatically improve the energy storage characteristics of the aerogel. These composites have demonstrated specific capacitances in excess of 200 F/g, in comparison to 95 F/g for the untreated aerogel.

  19. Fabrication of a vanadium-stainless steel test section for MHD testing of insulator coatings in flowing lithium

    Microsoft Academic Search

    C. B. Reed; R. F. Mattas; D. L. Smith; H. Chung; H. C. Tsai; W. R. Johnson; G. D. Morgan; G. W. Wille; C. Young

    1996-01-01

    To test the magnetohydrodynamic (MHD) pressure drop reduction performance of candidate insulator coatings for the ITER Vanadium\\/Lithium Breeding Blanket, a test section comprised of a V-4Cr-4Ti liner inside a stainless steel pipe was designed and fabricated. Theoretically, the MHD pressure drop reduction benefit resulting from an electrically insulating coating on a vanadium-lined pipe is identical to the benefit derived from

  20. New Approach to Image Aerogels by Scanning Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Solá, Francisco; Hurwitz, Frances; Yang, Jijing

    2011-03-01

    A new scanning electron microscopy (SEM) technique to image poor electrically conductive aerogels is presented. The process can be performed by non-expert SEM users. We showed that negative charging effects on aerogels can be minimized significantly by inserting dry nitrogen gas close to the region of interest. The process involves the local recombination of accumulated negative charges with positive ions generated from ionization processes. This new technique made possible the acquisition of images of aerogels with pores down to approximately 3nm in diameter using a positively biased Everhart-Thornley (E-T) detector. Well-founded concepts based on known models will also be presented with the aim to explain the results qualitatively.

  1. Bonding of silica aerogel with silicone resin GR650

    SciTech Connect

    Burnham, A.

    1987-05-08

    A method has been developed to bond smooth faces of silica aerogel together with Owens-Illinois silicone resin GR650. The resin is ground into a fine powder and deposited onto the aerogel surfaces. The pieces are then placed together, a pressure of 4 psi applied, and heated to 120/sup 0/C overnight. Continuous bonds with a thickness of less than 1 ..mu..m have been obtained. Tensile failure of the bond is usually cohesive, and strengths of about 10 psi have been obtained, which is approximately the tensile strength of the aerogel. Structural information on GR650 from GPC and /sup 29/Si, /sup 13/C and proton NMR is also presented.

  2. Neutronic optimization of solid breeder blankets for STARFIRE design

    SciTech Connect

    Gohar, Y.; Abdou, M.A.

    1980-01-01

    Extensive neutronic tradeoff studies were carried out to define and optimize the neutronic performance of the different solid breeder options for the STARFIRE blanket design. A set of criteria were employed to select the potential blanket materials. The basic criteria include the neutronic performance, tritium-release characteristics, material compatibility, and chemical stability. Three blanket options were analyzed. The first option is based on separate zones for each basic blanket function where the neutron multiplier is kept in a separate zone. The second option is a heterogeneous blanket type with two tritium breeder zones. In the first zone the tritium breeder is assembled in a neutron multiplier matrix behind the first wall while the second zone has a neutron moderator matrix instead of the neutron multiplier. The third blanket option is similar to the second concept except the tritium breeder and the neutron multiplier form a homogeneous mixture.

  3. Processing and waste disposal representative for fusion breeder blanket systems

    SciTech Connect

    Finn, P.A.; Vogler, S.

    1987-01-01

    This study is an evaluation of the waste handling concepts applicable to fusion breeder systems. Its goal is to determine if breeder blanket waste can be disposed of in shallow land burial, the least restrictive method under US Nuclear Regulatory regulations. The radionuclides expected in the materials used in fusion reactor blankets are described, as are plans for reprocessing and disposal of the components of different breeder blankets. An estimate of the operating costs involved in waste disposal is made.

  4. Carbon nanotube networks in epoxy composites and aerogels

    NASA Astrophysics Data System (ADS)

    Bryning, Mateusz B.

    This thesis describes the properties of carbon nanotube networks in epoxy composites and in novel carbon nanotube aerogels. SWNT Epoxy composites were created using a new procedure that enabled us to control SWNT concentration and dispersion quality in the composite. The composites exhibited percolation-like electrical conductivity with threshold volume fractions in the semi-dilute nanotube concentration regime. The observed electrical conductivites are described in terms of nanotube length, degree of aggregation, and sample homogeneity. By modifying the procedure to allow for nanotube chaining, conductive composites were created at SWNT volume fractions as low as 5.2 (+1.9/-0.5) x 10-5, the lowest reported to date. The thermal conductivity of SWNT-epoxy composites is also investigated. Composites were prepared using suspensions of SWNTs in N-N-Dimethylformamide (DMF) or surfactant stabilized aqueous SWNT suspensions. Thermal conductivity enhancement was observed in both types of composites, but DMF-processed composites showed an advantage at SWNT volume fractions between ? ˜ 0.001 to 0.005. Surfactant processed samples, however, allowed greater SWNT loading at which a larger overall enhancement (64 +/- 9) % at ? ˜ 0.1 was observed. The enhancement differences are attributed to a tenfold higher SWNT/solid-composite interfacial thermal resistance in the surfactant-processed composites over DMF-processed composites. The interfacial resistance was extracted from the data using effective medium theory. Carbon nanotube aerogels were created by freeze drying and critical point drying aqueous carbon nanotube gels. The resulting aerogels have densities of approximately 0.01 to 0.06 g/cm3 and maintain the dimensions of the wet gel. Critical point dried aerogels also preserve the microscopic three-dimensional network of debundled carbon nanotubes of the original gel. Pure SWNT aerogels are self-supporting. Reinforcement with small amounts of added polyvinyl alcohol (PVA) produces much stronger structures that can support at least 8000 times their own weight. Electrical conductivity of order 1 S/cm is observed in the self-supporting aerogels, and at least 10-2 S/cm can be achieved in PVA-reinforced aerogels through additional processing. The aerogels have potential applications in areas such as sensors, novel battery or supercapacitor electrodes, and ultra-light structural materials. They can be backfilled with polymers or other materials to create composites that retain the high conductivity of the network.

  5. Highly porous ceramic oxide aerogels having improved flexibility

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B. (Inventor); Nguyen, Baochau N. (Inventor)

    2012-01-01

    Ceramic oxide aerogels incorporating periodically dispersed flexible linkages are provided. The flexible linkages impart greater flexibility than the native aerogels without those linkages, and have been shown to reduce or eliminate the need for supercritical CO.sub.2-mediated drying of the corresponding wet gels. The gels may also be polymer cross-linked via organic polymer chains that are attached to and extend from surface-bound functional groups provided or present over the internal surfaces of a mesoporous ceramic oxide particle network via appropriate chemical reactions.

  6. Synthesis of highly crystalline sp2-bonded boron nitride aerogels.

    PubMed

    Rousseas, Michael; Goldstein, Anna P; Mickelson, William; Worsley, Marcus A; Woo, Leta; Zettl, Alex

    2013-10-22

    sp(2)-Bonded boron nitride aerogels are synthesized from graphene aerogels via carbothermal reduction of boron oxide and simultaneous nitridation. The color and chemical composition of the original gel change dramatically, while structural features down to the nanometer scale are maintained, suggesting a direct conversion of the carbon lattice to boron nitride. Scanning and transmission electron microscopies reveal a foliated architecture of wrinkled sheets, a unique morphology among low-density, porous BN materials. The converted gels display a high degree of chemical purity (>95%) and crystalline order and exhibit unique cross-linking structures. PMID:24011289

  7. Current Trends of Blanket Research and Development in Japan 5.The Frontiers of Research on Fusion Blanket Technology

    NASA Astrophysics Data System (ADS)

    Nishikawa, Masabumi; Fukada, Satoshi; Shimizu, Akihiko; Iguchi, Tetsuo

    Current topics concerning blanket technology are reviewed. In the chemical engineering/chemistry area, the qualitative and quantitative effects of mass transfer steps of tritium is important in the understanding of the behavior of bred tritium in the solid breeder blanket system. Such phenomena as adsorption, isotope exchange reactions, and water formation reaction at the grain surface produce profound effects on the behavior of the bred tritium in the blanket. Regarding the liquid system, the physical or chemical properties of Li, Li17Pb83 and Flibe as liquid blanket materials were compared. Some recent studies were introduced regarding tritium recovery from the liquid blanket materials, impurity removal from salts, ceramic coating of structural materials, and the vapor pressure of mixtures of metals or salts. Thermal hydraulic topics in relation to several candidate power reactor concepts are summarized. Emphasis is laid on the simultaneous removal of heat and tritium from the blanket and some aspects of forming effective power cycles are developed.

  8. Development of advanced blanket materials for a solid breeder blanket of a fusion reactor

    NASA Astrophysics Data System (ADS)

    Kawamura, H.; Ishitsuka, E.; Tsuchiya, K.; Nakamichi, M.; Uchida, M.; Yamada, H.; Nakamura, K.; Ito, H.; Nakazawa, T.; Takahashi, H.; Tanaka, S.; Yoshida, N.; Kato, S.; Ito, Y.

    2003-08-01

    The design of an advanced solid breeding blanket in a DEMO reactor requires a tritium breeder and a neutron multiplier that can withstand high temperatures and high neutron fluences, and the development of such advanced blanket materials has been carried out by collaboration between JAERI, universities and industries in Japan. The Li2TiO3 pebble fabricated by a wet process is a reference material as a tritium breeder, but its stability at high temperatures has to be improved for its application in a DEMO blanket. One of these improved materials, TiO2-doped Li2TiO3 pebbles, was successfully fabricated and studied. For the advanced neutron multiplier, beryllides that have a high melting point and good chemical stability have been studied. Some characterization of Be12Ti was conducted, and it became clear that it had lower swelling and tritium inventory than beryllium metal. Pebble fabrication study for Be12Ti was also performed and Be12Ti pebbles were successfully fabricated. These activities have shown that there is a bright prospect in realizing a DEMO blanket by the application of TiO2-doped Li2TiO3 and beryllides.

  9. Some catalytic applications of aerogels for environmental purposes

    Microsoft Academic Search

    G. M. Pajonk

    1999-01-01

    To protect our environment, catalysts are useful for the treatment of pollutants once they have been generated, or to prevent or at least to minimize their formation. To meet these requirements, very highly divided supports and active phases are necessary for satisfactory results. In particular, nanoparticles such as those obtained by sol–gel chemistry combined with supercritical drying methods (“aerogels”) may

  10. Preparing silica aerogel monoliths via a rapid supercritical extraction method.

    PubMed

    Carroll, Mary K; Anderson, Ann M; Gorka, Caroline A

    2014-01-01

    A procedure for the fabrication of monolithic silica aerogels in eight hours or less via a rapid supercritical extraction process is described. The procedure requires 15-20 min of preparation time, during which a liquid precursor mixture is prepared and poured into wells of a metal mold that is placed between the platens of a hydraulic hot press, followed by several hours of processing within the hot press. The precursor solution consists of a 1.0:12.0:3.6:3.5 x 10(-3) molar ratio of tetramethylorthosilicate (TMOS):methanol:water:ammonia. In each well of the mold, a porous silica sol-gel matrix forms. As the temperature of the mold and its contents is increased, the pressure within the mold rises. After the temperature/pressure conditions surpass the supercritical point for the solvent within the pores of the matrix (in this case, a methanol/water mixture), the supercritical fluid is released, and monolithic aerogel remains within the wells of the mold. With the mold used in this procedure, cylindrical monoliths of 2.2 cm diameter and 1.9 cm height are produced. Aerogels formed by this rapid method have comparable properties (low bulk and skeletal density, high surface area, mesoporous morphology) to those prepared by other methods that involve either additional reaction steps or solvent extractions (lengthier processes that generate more chemical waste).The rapid supercritical extraction method can also be applied to the fabrication of aerogels based on other precursor recipes. PMID:24637334

  11. Reinforcement of bacterial cellulose aerogels with biocompatible polymers

    PubMed Central

    Pircher, N.; Veigel, S.; Aigner, N.; Nedelec, J.M.; Rosenau, T.; Liebner, F.

    2014-01-01

    Bacterial cellulose (BC) aerogels, which are fragile, ultra-lightweight, open-porous and transversally isotropic materials, have been reinforced with the biocompatible polymers polylactic acid (PLA), polycaprolactone (PCL), cellulose acetate (CA), and poly(methyl methacrylate) (PMMA), respectively, at varying BC/polymer ratios. Supercritical carbon dioxide anti-solvent precipitation and simultaneous extraction of the anti-solvent using scCO2 have been used as core techniques for incorporating the secondary polymer into the BC matrix and to convert the formed composite organogels into aerogels. Uniaxial compression tests revealed a considerable enhancement of the mechanical properties as compared to BC aerogels. Nitrogen sorption experiments at 77 K and scanning electron micrographs confirmed the preservation (or even enhancement) of the surface-area-to-volume ratio for most of the samples. The formation of an open-porous, interpenetrating network of the second polymer has been demonstrated by treatment of BC/PMMA hybrid aerogels with EMIM acetate, which exclusively extracted cellulose, leaving behind self-supporting organogels. PMID:25037381

  12. Reinforcement of bacterial cellulose aerogels with biocompatible polymers.

    PubMed

    Pircher, N; Veigel, S; Aigner, N; Nedelec, J M; Rosenau, T; Liebner, F

    2014-10-13

    Bacterial cellulose (BC) aerogels, which are fragile, ultra-lightweight, open-porous and transversally isotropic materials, have been reinforced with the biocompatible polymers polylactic acid (PLA), polycaprolactone (PCL), cellulose acetate (CA), and poly(methyl methacrylate) (PMMA), respectively, at varying BC/polymer ratios. Supercritical carbon dioxide anti-solvent precipitation and simultaneous extraction of the anti-solvent using scCO2 have been used as core techniques for incorporating the secondary polymer into the BC matrix and to convert the formed composite organogels into aerogels. Uniaxial compression tests revealed a considerable enhancement of the mechanical properties as compared to BC aerogels. Nitrogen sorption experiments at 77K and scanning electron micrographs confirmed the preservation (or even enhancement) of the surface-area-to-volume ratio for most of the samples. The formation of an open-porous, interpenetrating network of the second polymer has been demonstrated by treatment of BC/PMMA hybrid aerogels with EMIM acetate, which exclusively extracted cellulose, leaving behind self-supporting organogels. PMID:25037381

  13. Preparation and flammability of poly(vinyl alcohol) composite aerogels.

    PubMed

    Chen, Hong-Bing; Wang, Yu-Zhong; Schiraldi, David A

    2014-05-14

    Poly(vinyl alcohol) (PVOH)-based aerogel composites with nanoscale silica, halloysite, montmorillonite (MMT), and laponite were prepared via a freeze-drying method. The PVOH/MMT and PVOH/laponite composites exhibit higher compressive moduli than the PVOH/SiO2 or PVOH/halloysite samples. Layered microstructures were observed for the samples except with PVOH/laponite, which showed irregular network morphologies. Thermogravimetric analysis of the aerogel samples showed increased thermal stability with the addition of nanofillers. The heat release measured by cone calorimetry, smoke release, and carbon monoxide production of the aerogel composites are all significantly decreased with the addition of nanofillers; these values are much lower than those for commercial expanded polystyrene foam. The fillers did not lead to obvious increases in the limiting oxygen index values, and the corresponding time to ignition values decrease. The ability to adjust the nanofiller levels in these foamlike aerogel composites allows for specific tuning of these products for fire safety. PMID:24731187

  14. Fractal Studies on Titanium-Silica Aerogels using SMARTer

    SciTech Connect

    Putra, E. Giri Rachman; Ikram, A.; Bharoto; Santoso, E. [Neutron Scattering Laboratory, BATAN, Kawasan Puspiptek Serpong, Tangerang 15314 (Indonesia); Fang, T. Chiar; Ibrahim, N. [Department of Physics, Faculty of Science Universiti Teknologi Malaysia (UTM), 81310 Skudai, Johor (Malaysia); Mohamed, A. Aziz [Materials Technology Group, Industrial Technology Division Agensi Nuklear Malaysia, 43000 Kajang (Malaysia)

    2008-03-17

    Power-law scattering approximation has been employed to reveal the fractal structures of solid-state titanium-silica aerogel samples. All small-angle neutron scattering (SANS) measurements were performed using 36 meters SANS BATAN spectrometer (SMARTer) at the neutron scattering laboratory (NSL) in Serpong, Indonesia. The mass fractal dimension of titanium-silica aerogels at low scattering vector q range increases from -1.4 to -1.92 with the decrease of acid concentrations during sol-gel process. These results are attributed to the titanium-silica aerogels that are growing to more polymeric and branched structures. At high scattering vector q range the Porod slope of -3.9 significantly down to -2.24 as the roughness of particle surfaces becomes higher. The cross over between these two regimes decreases from 0.4 to 0.16 nm{sup -1} with the increase of acid concentrations indicating also that the titanium-silica aerogels are growing.

  15. Extreme synthesis and chemical doping of diamond aerogel

    NASA Astrophysics Data System (ADS)

    Pauzauskie, Peter J.; Crowhurst, Jonathan C.; Worsley, Marcus A.; Laurence, Ted A.; Wang, Yinmin; Kilcoyne, A. L. D.; Weber, Peter K.; Willey, Trevor M.; Visbeck, Kenneth S.; Evans, William J.; Satcher, Joe H., Jr.

    2010-03-01

    Amorphous carbon aerogels have attracted much interest in recent years due to their low density, large intrinsic surface areas (>1000 m^2/g), large pore volume, low dielectric constant, and high strength. We use high-pressure (˜20 GPa) laser-heating (>600 C) within a diamond anvil cell (DAC) to convert the amorphous network of a low-density (40mg/cc) carbon aerogel into an ultrananocrystalline diamond aerogel. Photoluminescence spectroscopy and confocal time-correlated single-photon counting indicate the recovered material contains both negatively-charged and neutral nitrogen-vacancy (NV) complexes. Synchrotron scanning transmission x-ray microscopy (STXM) is used to compare the carbon electronic density-of-states of the amorphous starting material with the recovered diamond aerogel with ˜100 meV energy resolution. Finally, we use nanoscale secondary ion mass spectrometry to investigate doping of the resorcinol-formaldehyde starting material with the aim of chemically tuning heteroatomic point defects within this diamond material system.

  16. New organic aerogels based upon a phenolic-furfural reaction

    SciTech Connect

    Hrubesh, L.W.

    1994-09-01

    The aqueous polycondensation of (1) resorcinol with formaldehyde and (2) melamine with formaldehyde are two proven synthetic routes for the formation of organic aerogels. Recently, we have discovered a new type of organic aerogel based upon a phenolic-furfural (PF) reaction. This sol-gel polymerization has a major advantage over past approaches since it can be conducted in alcohol (e.g., 1-propanol), thereby eliminating the need for a solvent exchange step prior to supercritical drying from carbon dioxide. The resultant aerogels are dark brown in color and can be converted to a carbonized version upon pyrolysis in an inert atmosphere. BET surface areas of 350--600 m{sup 2}/g have been measured, and transmission electron microscopy reveals an interconnected structure of irregularly-shaped particles or platelets with {approximately}10 nm dimensions. Thermal conductivities as low as 0.015 W/m-K have been recorded for PF aerogels under ambient conditions. This paper describes the chemistry-structure-property relationships of these new materials in detail.

  17. Noble Metal Immersion Spectroscopy of Silica Alcogels and Aerogels

    Microsoft Academic Search

    David D. Smith; Laurent Sibille; Erica Ignont; Raymond J. Cronise; David A. Noever

    2000-01-01

    We have fabricated aerogels containing gold and silver nanoparticles for gas catalysis applications. The technique of immersion spectroscopy is extended to porous or heterogeneous media allowing the surface area of metal available for catalytic gas reaction to be determined. Specifically, we apply the predominant effective medium theories to the heterogeneous interlayer surrounding each particle to determine the average fractional composition

  18. High temperature - low mass solar blanket

    NASA Technical Reports Server (NTRS)

    Mesch, H. G.

    1979-01-01

    Interconnect materials and designs for use with ultrathin silicon solar cells are discussed, as well as the results of an investigation of the applicability of parallel-gap resistance welding for interconnecting these cells. Data relating contact pull strength and cell electrical degradation to variations in welding parameters such as time, voltage and pressure are presented. Methods for bonding ultrathin cells to flexible substances and for bonding thin (75 micrometers) covers to these cells are described. Also, factors influencing fabrication yield and approaches for increasing yield are discussed. The results of vacuum thermal cycling and thermal soak tests on prototype ultrathin cell test coupons and one solar module blanket are presented.

  19. Review of blanket designs for advanced fusion reactors

    Microsoft Academic Search

    T. Ihli; T. K. Basu; L. M. Giancarli; S. Konishi; S. Malang; F. Najmabadi; S. Nishio; A. R. Raffray; C. V. S. Rao; A. Sagara; Y. Wu

    2008-01-01

    The dominating fraction of the power generated by fusion in the reactor is captured by neutron moderation in the blanket surrounding the plasma. From this, the efficiency of the fusion plant is predominated by the technologies applied to make electricity or hydrogen from the neutrons. The main blanket concepts addressed in this paper are advanced ceramic breeder concepts, dual coolant

  20. Conceptual design of a self-cooled Flibe blanket

    SciTech Connect

    Sze, D.K.; Jung, J.; Cheng, E.T.; Piet, S.; Klein, A.

    1986-06-01

    A self-cooled Flibe blanket concept has been developed. The problems associated with tritium breeding, tritium containment, and corrosion have been investigated and potential solutions developed. A highly efficient and compact blanket and power conversion system has been incorporated. The resulting system is low pressure with high thermal efficiency and is inherently safe.

  1. AUTOMATIC SLUDGE BLANKET CONTROL IN AN OPERATING GRAVITY THICKENER

    EPA Science Inventory

    The purposes of this study were to evaluate some of the hardware required to monitor and control the operation of a gravity thickener and to identify any benefits associated with improved sludge blanket level control. An automatic sludge blanket level control system was installed...

  2. US blanket technology programs. [Directory of current research

    SciTech Connect

    Nygren, R.E.

    1985-01-01

    Experimental research in US programs related to blanket technology is described through brief summaries of the objectives, facilities, recent experimental results and principal investigators for the Blanket Technology Program, TRIO-1 Experiment, TSTA, Fusion Hybrid Program and selected activities in the Fusion Materials and Fusion Safety Programs in neutronics research.

  3. Controls of soil pipe frequency in upland blanket peat

    Microsoft Academic Search

    Joseph Holden

    2005-01-01

    Soil pipes were surveyed in 160 British blanket peat catchments using consistent application of ground-penetrating radar. Soil pipes were found in all catchments. The mean frequency of piping was 69 per kilometer of surveyed transect. Land management (moorland gripping) appears to exert the most important control on hillslope pipe frequency in blanket peats. Management practice in peatlands may therefore induce

  4. Natural uranium hybrid blankets for the Ayman project

    SciTech Connect

    Al-Kusayer, T.A.; Sahin, S.

    1983-12-01

    In the framework of the AYMAN fusion-fission (hybrid) experimental reactor project, a series of calculations have been performed in order to evaluate the optimal parameters to prepare sufficient information prior to final decision for the design work. A potential experimental hybrid blanket may contain natural - UO/sub 2/ - fuel. This study searches the design parameters for two types of hybrid blankets: a. Blankets with a high energy multiplication factor M to burn the fissile fuel in situ representing a power generating hybrid reactor complex. b. Blankets with a high fissile and fusile breeding capability, representing a hybrid reactor, designed as a fuel factory. Li will be used as tritium breeder in the early phase of investigations. The investigated experimental hybrid blankets, in cylinderical geometry, consist of the following components: 1) Plasma chamber with a radius of 38.7 cm 2) First wall: SS-316, 1.3 cm, corresponding to the first wall of TFTR.

  5. Fibrous refractory composite insulation

    NASA Technical Reports Server (NTRS)

    Goldstein, H. E.; Smith, M.; Leiser, D. B.

    1974-01-01

    Family of high-temperature, low-density refractory composite insulations made from aluminoborosilicate and silica fibers has insulating material with improved mechanical and thermal properties. Composition is useful for reusable heat-shield materials.

  6. Thermal Insulation Systems

    E-print Network

    Stanley, T. F.

    1982-01-01

    cost reduction programs. One of the best places to start with energy conservation is to employ proper insulation systems. This article discusses the significant properties of thermal insulation materials primarily for industrial application. Some...

  7. Silica reusable surface insulation

    NASA Technical Reports Server (NTRS)

    Goldstein, H. E.; Smith, M.; Leiser, D. B. (inventors)

    1976-01-01

    A reusable silica surface insulation material is provided by bonding amorphous silica fibers with colloidal silica at an elevated temperature. The surface insulation is ordinarily manufactured in the form of blocks (i.e., tiles).

  8. Multilayer insulation materials for reusable space vehicles.

    NASA Technical Reports Server (NTRS)

    Leonhard, K. E.; Hyde, E. H.

    1971-01-01

    Results of an extensive study conducted to evaluate multilayer insulation (MLI) materials suitable for repeated space vehicle operation are presented. Materials studied were radiation shields, shield spacers, blanket face sheets, fasteners, and adhesives. The Superfloc MLI concept - Kapton shields goldized on both sides as the radiation barrier with Dacron flock tufts as the spacers - appeared to be an excellent MLI for reusable cryogenic tankage. Superfloc configurations consisting of various combinations of film, spacer, and adhesive materials were manufactured and tested. Tensile, flexing, expansion, and cycling tests were performed on goldized Kapton and Mylar Superfloc and Beta glass reinforced Pyre ML face sheet material. A face sheet material that retains its shape was developed. Polyphenylene oxide material was selected for fabricating lightweight twin and tri-pin fasteners, together with grommets, face sheets, and reinforcement slabs. Measured material thermal conductivity values are tabulated.

  9. The breeding blanket interface (BBI): recent results for the solid breeder and the aqueous salt solution blanket concepts

    Microsoft Academic Search

    R. G. Clemmer; P. A. Finn; L. R. Greenwood; D. K. Sze; J. R. Bartlit; R. Sherman; J. L. Anderson; H. Yoshida; Y. Naruse; K. Okuno; M. Enoeda; Ibaraki

    1989-01-01

    The Tritium Systems Test Assembly (TSTA) at Los Alamos, New Mexico, is a full-scale facility dedicated to testing tritium processing for fusion reactors. Adding a breeder blanket interface (BBI) to the TSTA is being studied. The BBI is to test the processing required for the tritium output streams for the various fusion-reactor breeder blankets. In the current phase of the

  10. Vacuum insulator coating development

    Microsoft Academic Search

    I. S. Roth; P. S. Sincerny; L. Mandelcorn; M. Mendelsohn; D. Smith; T. G. Engel; L. Schlitt; C. M. Cooke

    1997-01-01

    The authors discuss the electrical and mechanical requirements for vacuum insulators in high peak power generators. To increase the lifetime of these insulators, they have developed a coating called Dendresist. This coating has extended the insulator lifetime on the PITHON, DM2, CASINO, and Double-EAGLE pulsed power generators. They describe its development, and compare its electrical and mechanical strength to that

  11. Mott Metal Insulator Transitions

    E-print Network

    Budker, Dmitry

    Physics Letters 95, no. 4 (2009) 14 #12;Mott Insulators: Actuators Bimorph Actuators Thermal Sensing Liu, despite being a "toy" model, is used in active research Crystal structures matter! Mott insulators haveMott Metal Insulator Transitions Satej Soman, Robert Tang-Kong March 21, Physics 141A 1 #12

  12. Fractional Topological Insulators

    Microsoft Academic Search

    Michael Levin; Ady Stern

    2009-01-01

    We analyze generalizations of two-dimensional topological insulators which can be realized in interacting, time reversal invariant electron systems. These states, which we call fractional topological insulators, contain excitations with fractional charge and statistics in addition to protected edge modes. In the case of sz conserving toy models, we show that a system is a fractional topological insulator if and only

  13. Thermal performance of a liquid hydrogen tank multilayer insulation system at warm boundary temperatures of 630, 530, and 152 R

    NASA Astrophysics Data System (ADS)

    Stochl, Robert J.; Knoll, Richard H.

    1991-06-01

    The results are presented of a study conducted to obtain experimental heat transfer data on a liquid hydrogen tank insulated with 34 layers of MLI (multilayer insulation) for warm side boundary temperatures of 630, 530, and 150 R. The MLI system consisted of two blankets, each blanket made up of alternate layers of double silk net (16 layers) and double aluminized Mylar radiation shields (15 layers) contained between two cover sheets of Dacron scrim reinforced Mylar. The insulation system was designed for and installed on a 87.6 in diameter liquid hydrogen tank. Nominal layer density of the insulation blankets is 45 layers/in. The insulation system contained penetrations for structural support, plumbing, and electrical wiring that would be representative of a cryogenic spacecraft. The total steady state heat transfer rates into the test tank for shroud temperatures of 630, 530, 152 R were 164.4, 95.8, and 15.9 BTU/hr respectively. The noninsulation heat leaks into the tank (12 fiberglass support struts, tank plumbing, and instrumentation lines) represent between 13 to 17 pct. of the total heat input. The heat input values would translate to liquid H2 losses of 2.3, 1.3, and 0.2 pct/day, with the tank held at atmospheric pressure.

  14. Thermal performance of a liquid hydrogen tank multilayer insulation system at warm boundary temperatures of 630, 530, and 152 R

    NASA Technical Reports Server (NTRS)

    Stochl, Robert J.; Knoll, Richard H.

    1991-01-01

    The results are presented of a study conducted to obtain experimental heat transfer data on a liquid hydrogen tank insulated with 34 layers of MLI (multilayer insulation) for warm side boundary temperatures of 630, 530, and 150 R. The MLI system consisted of two blankets, each blanket made up of alternate layers of double silk net (16 layers) and double aluminized Mylar radiation shields (15 layers) contained between two cover sheets of Dacron scrim reinforced Mylar. The insulation system was designed for and installed on an 87.6 in. diameter liquid hydrogen tank. Nominal layer density of the insulation blankets is 45 layers/in. The insulation system contained penetrations for structural support, plumbing, and electrical wiring that would be representative of a cryogenic spacecraft. The total steady state heat transfer rates into the test tank for shroud temperatures of 630, 530, 152 R were 164.4, 95.8, and 15.9 BTU/hr, respectively. The noninsulation heat leaks into the tank (12 fiberglass support struts, tank plumbing, and instrumentation lines) represent between 13 to 17 pct. of the total heat input. The heat input values would translate to liquid H2 losses of 2.3, 1.3, and 0.2 pct/day, with the tank held at atmospheric pressure.

  15. Thermal performance of a liquid hydrogen tank multilayer insulation system at warm boundary temperatures of 630, 530, and 152 R

    NASA Astrophysics Data System (ADS)

    Stochl, Robert J.; Knoll, Richard H.

    1991-06-01

    The results are presented of a study conducted to obtain experimental heat transfer data on a liquid hydrogen tank insulated with 34 layers of MLI (multilayer insulation) for warm side boundary temperatures of 630, 530, and 150 R. The MLI system consisted of two blankets, each blanket made up of alternate layers of double silk net (16 layers) and double aluminized Mylar radiation shields (15 layers) contained between two cover sheets of Dacron scrim reinforced Mylar. The insulation system was designed for and installed on an 87.6 in. diameter liquid hydrogen tank. Nominal layer density of the insulation blankets is 45 layers/in. The insulation system contained penetrations for structural support, plumbing, and electrical wiring that would be representative of a cryogenic spacecraft. The total steady state heat transfer rates into the test tank for shroud temperatures of 630, 530, 152 R were 164.4, 95.8, and 15.9 BTU/hr, respectively. The noninsulation heat leaks into the tank (12 fiberglass support struts, tank plumbing, and instrumentation lines) represent between 13 to 17 pct. of the total heat input. The heat input values would translate to liquid H2 losses of 2.3, 1.3, and 0.2 pct/day, with the tank held at atmospheric pressure.

  16. Synthesis, characterization and application of highly crystalline sp2 - bonded boron nitride aerogels

    NASA Astrophysics Data System (ADS)

    Pham, Thang; Goldstein, Anna; Worsley, Marcus; Woo, Leta; Mickelson, William; Zettl, Alex

    2015-03-01

    Aerogels have much potential in both research and industrial applications due to high surface area, low density and fine pore size distribution. Here we report a versatile synthesis and thorough structure characterization of three-dimensional aerogels composed of highly crystalline sp2 - bonded BN layers formed by carbothermal reaction. The structure, crystallinity and bonding of the as-prepared BN aerogels were elucidated by x-ray diffraction, nuclear magnetic resonance of 11B, transmission electron microscopy (TEAM) and resonant soft x-ray scattering. The macroscopic roughness of the aerogel's surface causes it to be superhydrophobic with a contact angle of 155 +/- 3° and high oil uptake (up to 1500 wt%). The used BN aerogel can be regenerated by different heat treatments and still maintain the crystalline porous structure and adsorption capacity. The highly crystalline, chemically pure, thermally stable and porous sp2 - boron nitride aerogel is an ideal host for liquids, gases and other nanomaterials.

  17. Development of transparent silica aerogel over a wide range of densities

    E-print Network

    Tabata, Makoto; Ishii, Yoshikazu; Kawai, Hideyuki; Sumiyoshi, Takayuki; Yokogawa, Hiroshi; 10.1016/j.nima.2010.02.241

    2011-01-01

    We have succeeded in developing hydrophobic silica aerogels over a wide range of densities (i.e. refractive indices). A pinhole drying method was invented to make possible producing highly transparent aerogels with entirely new region of refractive indices of 1.06-1.26. Obtained aerogels are more transparent than conventional ones, and the refractive index is well controlled in the pinhole drying process. A test beam experiment was carried out in order to evaluate the performance of the pinhole-dried aerogels as a Cherenkov radiator. A clear Cherenkov ring was successfully observed by a ring imaging Cherenkov counter. We also developed monolithic and hydrophobic aerogels with a density of 0.01 g/cm^3 (a low refractive index of 1.0026) as a cosmic dust capturer for the first time. Consequently, aerogels with any refractive indices between 1.0026 and 1.26 can be produced freely.

  18. Robust superhydrophobic bridged silsesquioxane aerogels with tunable performances and their applications.

    PubMed

    Wang, Zhen; Wang, Dong; Qian, Zhenchao; Guo, Jing; Dong, Haixia; Zhao, Ning; Xu, Jian

    2015-01-28

    Aerogels are a family of highly porous materials whose applications are commonly restricted by poor mechanical properties. Herein, thiol-ene chemistry is employed to synthesize a series of novel bridged silsesquioxane (BSQ) precursors with various alkoxy groups. On the basis of the different hydrolyzing rates of the methoxy and ethoxy groups, robust superhydrophobic BSQ aerogels with tailorable morphology and mechanical performances have been prepared. The flexible thioether bridge contributes to the robustness of the as-formed aerogels, and the property can be tuned on the basis of the distinct combinations of alkoxy groups with the density of the aerogels almost unchanged. To the best of our knowledge, the lowest density among the ambient pressure dried aerogels is obtained. Further, potential application of the aerogels for oil/water separation and acoustic materials has also been presented. PMID:25558778

  19. Nanoscale structure and superhydrophobicity of sp(2)-bonded boron nitride aerogels.

    PubMed

    Pham, Thang; Goldstein, Anna P; Lewicki, James P; Kucheyev, Sergei O; Wang, Cheng; Russell, Thomas P; Worsley, Marcus A; Woo, Leta; Mickelson, William; Zettl, Alex

    2015-06-01

    Aerogels have much potential in both research and industrial applications due to their high surface area, low density, and fine pore size distribution. Here we report a thorough structural study of three-dimensional aerogels composed of highly crystalline sp(2)-bonded boron nitride (BN) layers synthesized by a carbothermic reduction process. The structure, crystallinity and bonding of the as-prepared BN aerogels are elucidated by X-ray diffraction, (11)B nuclear magnetic resonance, transmission electron microscopy, and resonant soft X-ray scattering. The macroscopic roughness of the aerogel's surface causes it to be superhydrophobic with a contact angle of ?155° and exhibit high oil uptake capacity (up to 1500 wt%). The oil can be removed from the BN aerogel by oxidizing in air without damaging the crystalline porous structure of the aerogel or diminishing its oil absorption capacity. PMID:26007693

  20. The Breeding Blanket Interface (BBI): Recent results for the solid breeder and the aqueous salt solution blanket concepts

    SciTech Connect

    Clemmer, R.G.; Finn, P.A.; Greenwood, L.R.; Sze, D.K.; Bartlit, J.R.; Sherman, R.; Anderson, J.L.; Yoshida, H.; Naruse, Y.; Enoeda, M.; Okuno, K. (Argonne National Lab., IL (USA); Los Alamos National Lab., NM (USA); Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan))

    1989-10-01

    The Tritium Systems Test Assembly (TSTA) at Los Alamos is a full-scale facility dedicated to testing tritium processing for fusion reactors. We are involved in a study of adding a Breeder Blanket Interface (BBI) to the TSTA. The BBI is to test the processing required for the tritium output streams for the various fusion reactor breeder blankets. In the current phase of the study, we are evaluating the characteristics of the output from various breeding blankets types. Emphasis is placed on defining the output stream with respect to H/T ratio, impurity content, and radionuclide content. Reported herein is an assessment for two blanket concepts: solid breeder blanket (ceramic, Li{sub 2}O), and aqueous salt solution. 24 refs., 2 figs., 2 tabs.

  1. Study of multilayered insulation pipe penetration. Thermal acoustic oscillation

    NASA Technical Reports Server (NTRS)

    Lovin, J. K.

    1974-01-01

    Tests were conducted to determine the net heat leak to a source of liquid nitrogen caused by a metal penetration through the blanket of multilayer insulation. The conditions under which the tests were conducted are described. A graph of the theoretical and experimental temperature distribution is developed for comparison. The variables involved in the computer program to process the data are defined. A study was conducted to develop analytical methods for predicting the effect and magnitudes of thermoacoustic oscillations on the penetration heat leak to cryogens. The oscillations develop as a result of large thermal gradients imposed on a compressible fluid. The predominant amplitudes and frequencies of the thermal acoustic oscillations were investigated.

  2. Luminescent studies of fluorescent chromophore-doped silica aerogels for flat panel display applications

    SciTech Connect

    Glauser, S.A.C. [California Univ., Davis, CA (United States). Dept. of Applied Science; Lee, H.W.H. [Lawrence Livermore National Lab., CA (United States)

    1997-04-01

    The remarkable optical and electronic properties of doped and undoped silica aerogels establish their utility as unique, mulitfunctional host materials for fluorescent dyes and other luminescent materials for display and imaging applications. We present results on the photoluminescence, absorption, and photoluminescence excitation spectra of undoped silica aerogels and aerogels doped with Er{sup 3+}, rhodamine 6G (R6G), and fluorescein. 4 refs., 12 figs.

  3. Interference coating by hydrophobic aerogel-like SiO 2 thin films

    Microsoft Academic Search

    Qinyuan Zhang; J. Wang; G. Wu; J. Shen; S. Buddhudu

    2001-01-01

    The present paper presents a novel method of preparation of hydrophobic aerogel-like SiO2 thin films by means of a two-step acid\\/base derived silica sol at an ambient pressure without any supercritical drying. Crack free aerogel-like SiO2 thin films having thickness of 100–400nm, and refractive indices of 1.13–1.25 have been obtained upon heating at different temperatures. By using the silica aerogel-like

  4. Cubic topological Kondo insulators.

    PubMed

    Alexandrov, Victor; Dzero, Maxim; Coleman, Piers

    2013-11-27

    Current theories of Kondo insulators employ the interaction of conduction electrons with localized Kramers doublets originating from a tetragonal crystalline environment, yet all Kondo insulators are cubic. Here we develop a theory of cubic topological Kondo insulators involving the interaction of ?(8) spin quartets with a conduction sea. The spin quartets greatly increase the potential for strong topological insulators, entirely eliminating the weak topological phases from the diagram. We show that the relevant topological behavior in cubic Kondo insulators can only reside at the lower symmetry X or M points in the Brillouin zone, leading to three Dirac cones with heavy quasiparticles. PMID:24329462

  5. Aerosol Blanket Likely Thinned During 1990s

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Each day, a blanket of tiny particles drifting through the Earth's atmosphere filters out some of the sunlight headed for the planet's surface. These aerosols, including dust, smoke, and human-produced pollution, can reflect incoming light or absorb it, directly affecting the Earth's energy balance and climate. Aerosols also influence the climate indirectly, by affecting the brightness and amount of clouds. Research by NASA scientists on global aerosol patterns since the 1990s indicate the global aerosol blanket has likely thinned, allowing more sunlight to reach the Earth's surface over the past decade. The thinning of the blanket is shown by this trio of images based on satellite observations of aerosol optical thickness, a measurement that scientists use to describe how much the aerosols filter the incoming sunlight. Higher optical thickness (orange and red) means more sunlight blocking. The globes show average aerosol optical thickness for 1988-1991 (top), 2002-2005 (middle), and the change between the two time periods (bottom). Overall, the 1988-1991 image appears redder, a sign that aerosols were blocking more incoming sunlight; the 2002-2005 image has more light yellow areas. In the bottom image, small pockets of red (increased aerosol optical thickness), mostly near land masses in the Northern Hemisphere, are far outnumbered by blue areas (decreased aerosol optical thickness). Because they block incoming sunlight from reaching Earth's surface, aerosols may counterbalance greenhouse gas warming. The decline in the dimming power of aerosols over the past decade may have made the greenhouse warming trend more evident in the past decade than in previous decades. The scientists describe their results as a 'likely' trend because the National Oceanic and Atmospheric Administration satellite sensors they used in their analysis were not specifically designed to observe aerosols, and may contain some errors. However, specific, major aerosol events, such as large volcanic eruptions, show up in the right place at the right time in the observations, and the data also agree with available ground-based observations. Ongoing NASA missions such as the Terra, Aqua, Aura, and Cloudsat/CALIPSO, as well as upcoming missions such as Glory, will provide the data scientists need to monitor aerosol trends over time. NASA image created by Jesse Allen, using data provided courtesy of Michael Mischenko and Igor Geogdzhayev, NASA Goddard Institute of Space Studies.

  6. Nanoscale structure and superhydrophobicity of sp2-bonded boron nitride aerogels

    NASA Astrophysics Data System (ADS)

    Pham, Thang; Goldstein, Anna P.; Lewicki, James P.; Kucheyev, Sergei O.; Wang, Cheng; Russell, Thomas P.; Worsley, Marcus A.; Woo, Leta; Mickelson, William; Zettl, Alex

    2015-06-01

    Aerogels have much potential in both research and industrial applications due to their high surface area, low density, and fine pore size distribution. Here we report a thorough structural study of three-dimensional aerogels composed of highly crystalline sp2-bonded boron nitride (BN) layers synthesized by a carbothermic reduction process. The structure, crystallinity and bonding of the as-prepared BN aerogels are elucidated by X-ray diffraction, 11B nuclear magnetic resonance, transmission electron microscopy, and resonant soft X-ray scattering. The macroscopic roughness of the aerogel's surface causes it to be superhydrophobic with a contact angle of ~155° and exhibit high oil uptake capacity (up to 1500 wt%). The oil can be removed from the BN aerogel by oxidizing in air without damaging the crystalline porous structure of the aerogel or diminishing its oil absorption capacity.Aerogels have much potential in both research and industrial applications due to their high surface area, low density, and fine pore size distribution. Here we report a thorough structural study of three-dimensional aerogels composed of highly crystalline sp2-bonded boron nitride (BN) layers synthesized by a carbothermic reduction process. The structure, crystallinity and bonding of the as-prepared BN aerogels are elucidated by X-ray diffraction, 11B nuclear magnetic resonance, transmission electron microscopy, and resonant soft X-ray scattering. The macroscopic roughness of the aerogel's surface causes it to be superhydrophobic with a contact angle of ~155° and exhibit high oil uptake capacity (up to 1500 wt%). The oil can be removed from the BN aerogel by oxidizing in air without damaging the crystalline porous structure of the aerogel or diminishing its oil absorption capacity. Electronic supplementary information (ESI) available: High resolution TEM images of different portions of sample, photos of aerogels in oil bath over time, thermal gravimetric analysis data of the aerogels, and X-ray diffraction patterns of as-synthesized BN aerogels, oil-absorbed aerogels and oil droplet. See DOI: 10.1039/c5nr01672j

  7. Overview of EU activities on DEMO liquid metal breeder blanket

    SciTech Connect

    Giancarli, L.; Proust, E. [DRN/DMT/SERMA, Gif-sur-Yvette (France); Benamati, G. [CRE Brasimone, Camugnano (Italy)] [and others

    1994-12-31

    The European test-blanket development programme, started in 1988, is aiming at the selection by 1995 of two DEMO-relevant blanket lines to be tested in ITER. At present, four lines of blanket are under development, two of them using solid and the other two liquid breeder materials. As far as liquid breeders are concerned, two lines of blankets have been selected within the European Union, the water-cooled lithium-lead (the eutectic Pb-17Li) blankets and the dual-coolant Pb-17Li blankets. Designs have been developed considering an agreed set of DEMO specifications, such as, for instance, a fusion power of 2,200 MW, a neutron wall-loading of 2MW/m{sup 2}, a life-time of 20,000 hours, and the use of martensitic steel as a structural material. Moreover, an experimental program has been set up in order to address the main critical issues for each line. The present paper gives an overview of both design and experimental activities within the European Union concerning these two lines of liquid breeder blankets.

  8. Fusion Engineering and Design 81 (2006) 393405 Breeding Blanket Modules testing in ITER

    E-print Network

    Abdou, Mohamed

    2006-01-01

    Fusion Engineering and Design 81 (2006) 393­405 Breeding Blanket Modules testing in ITER Available online 18 January 2006 Abstract Testing of Breeding Blanket Modules is one of ITER's primary reserved. Keywords: ITER; TBWG; Test Blanket Module; TBM; Breeding blanket Corresponding author. Tel.: +33

  9. Development of fusion blanket technology for the DEMO reactor.

    PubMed

    Colling, B R; Monk, S D

    2012-07-01

    The viability of various materials and blanket designs for use in nuclear fusion reactors can be tested using computer simulations and as parts of the test blanket modules within the International Thermonuclear Experimental Reactor (ITER) facility. The work presented here focuses on blanket model simulations using the Monte Carlo simulation package MCNPX (Computational Physics Division Los Alamos National Laboratory, 2010) and FISPACT (Forrest, 2007) to evaluate the tritium breeding capability of a number of solid and liquid breeding materials. The liquid/molten salt breeders are found to have the higher tritium breeding ratio (TBR) and are to be considered for further analysis of the self sufficiency timing. PMID:22112596

  10. Fission-suppressed blankets for fissile fuel breeding fusion reactors

    NASA Astrophysics Data System (ADS)

    Lee, J. D.; Moir, R. W.

    1981-07-01

    Two blanket concepts for deuterium-tritium (DT) fusion reactors are presented which maximize fissile fuel production while at the same time suppress fission reactions. By suppressing fission reactions, the reactor will be less hazardous, and therefore easier to design, develop, and license. A fusion breeder operating a given nuclear power level can produce much more fissile fuel by suppressing fission reactions. The two blankets described use beryllium for neutron multiplication. One blanket uses two separate circulating molten salts: one salt for tritium breeding and the other salt for U-233 breeding. The other uses separate solid forms of lithium and thorium for breeding and helium for cooling.

  11. Preparation of silica aerogels with improved mechanical properties and extremely low thermal conductivities through modified sol-gel process

    E-print Network

    Zuo, Yanjia

    2010-01-01

    Reported silica aerogels have a thermal conductivity as low as 15 mW/mK. The fragility of silica aerogels, however, makes them impractical for structural applications. The purpose of the study is to improve the ductility ...

  12. Electrochemical behavior of carbon aerogels derived from different precursors

    SciTech Connect

    Pekala, R.W.; Alviso, C.T.; Nielson, J.K.; Tran, T.D. [Lawrence Livermore National Lab., CA (United States); Reynolds, G.M.; Dresshaus, M.S. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Physics

    1995-04-01

    The ability to tailor the structure and properties of porous carbons has led to their increased use as electrodes in energy storage devices. Our research focuses on the synthesis and characterization of carbon aerogels for use in electrochemical double layer capacitors. Carbon aerogels are formed from the sol-gel polymerization of (1) resorcinol-formaldehyde or (2) phenolic-furfural, followed by supercritical drying from carbon dioxide, and subsequent pyrolysis in an inert atmosphere. These materials can be produced as monoliths, composites, thin films, powders, or microspheres. In all cases, the areogels have an open-cell structure with an ultrafine pore size (<100 nm), high surface area (400-1 100 m{sup 2}/g), and a solid matrix composed of interconnected particles, fibers, or platelets with characteristic dimensions of 10 nm. This paper examines the effects of the carbon precursor and processing conditions on electrochemical performance in aqueous and organic electrolytes.

  13. Characterization of Silica-Containing Aluminum Hydroxide and Oxide Aerogels

    Microsoft Academic Search

    Marcella Trombetta; Guido Busca; Ronald J. Willey

    1997-01-01

    Pure and silica-containing Al hydroxide aerogels were prepared by the supercritical drying method. The samples were later calcined, giving rise to alumina and Si–Al mixed oxides. The materials were characterized from the points of view of their bulk and surface structures. The Si-free material before calcination is well-crystallized boehmite that converts to ?-alumina by calcination. The silica-containing hydroxides are composed

  14. Structural characterization of SiO 2 aerogels

    Microsoft Academic Search

    B. Himmel; H. Bürger; Th. Gerber; A. Olbertz

    1995-01-01

    SiO2 aerogels with densities between 0.131 and 0.182 g\\/cm3 were prepared by CO2 supercritical drying of wet gels formed from differently concentrated TMOS solutions by hydrolytic polycondensation under basic conditions (pH ? 8). The formation and growth of SiO2 particles in the originally homogeneous starting solutions has been followed in situ by SAXS (small-angle X-ray scattering). A chemical limited particle

  15. Structure and EDLC characteristics of pitch-based carbon aerogels

    Microsoft Academic Search

    Xianhua Zeng; Dingcai Wu; Ruowen Fu; Huajie Lai

    2008-01-01

    Morphology and porous structure of the pitch-based carbon aerogels (CAs) were characterized by scanning electron microscopy (SEM) and N2 adsorption–desorption measurement. Their electrochemical performances as electric double-layer capacitor (EDLC) electrodes were studied by cyclic voltammetry and galvanostatic charge–discharge measurements. It was found that the particle size of the CAs decreased with the increase of the volume ratio of toluene to

  16. Performance Results of the AMS-01 Aerogel Threshold Cherenkov

    E-print Network

    F. Mayet

    2000-02-16

    The Alpha Magnetic Spectrometer (AMS) was flown in june 1998 on board of the space shuttle Discovery (flight STS-91) at an altitude ranging between 320 and 390 km. This preliminary version of AMS included an Aerogel Threshold Cherenkov detector (ATC) to separate antiprotons from electron background, for momenta less than 3.5 GeV/c. In this paper, the design and physical principles of ATC will be discussed briefly, then the performance results of the ATC will be presented.

  17. Preparation-morphology-performance relationships in cobalt aerogels as supercapacitors.

    PubMed

    Peterson, Geneva R; Hung-Low, Fernando; Gumeci, Cenk; Bassett, Will P; Korzeniewski, Carol; Hope-Weeks, Louisa J

    2014-02-12

    The ability to direct the morphology of cobalt sol-gel materials by using the simple synthetic parameters in epoxide-driven polycondensations has been dramatically demonstrated, and the influence of such morphological differences upon the supercapacity of the materials has been explored. Precursor salt, epoxide, and solvent all influence the speed of the sol-gel transition and the size and shape of the features observed in the as-prepared materials, thereby leading to highly varied microstructures including spheres, sponge-like networks, and plate assemblies of varied size. These morphological features of the as-prepared cobalt aerogels were observed for the first time by high resolution scanning electron microscopy (HRSEM). The as-prepared aerogel materials were identified by powder X-ray diffraction and thermogravimetry as weakly crystalline or amorphous cobalt basic salts with the general formula Co(OH)(2-n)X(n) where X = Cl or NO3 according to the precursor salt used in the synthesis. For all samples, the morphology was preserved through mild calcining to afford spinel phase Co3O4 in a variety of microstructures. Wide-ranging specific surface areas were determined for the as-prepared and calcined phases by physisorption analysis in agreement with the morphologies observed by HRSEM. The Co3O4 aerogels were evaluated for their supercapacitive performance by cyclic voltammetry. The various specimens exhibit capacitances ranging from 110 to 550 F g(-1) depending upon the attributes of the particular aerogel material, and the best specimen was found to have good cycle stability. These results highlight the epoxide-driven sol-gel condensation as a versatile preparative route that provides wide scope in materials' properties and enables the analysis of structure-performance relationships in metal oxide materials. PMID:24417220

  18. Thermal expansion of helium filled Aerogel at the lambda point

    NASA Astrophysics Data System (ADS)

    Thibault, P.; Prejean, J. J.; Puech, L.

    1992-11-01

    Under reasonable assumptions, we show that He-filled Aerogels should exhibit a strong negative thermal expansion at the ? point : ?=-10-3/K. We observed an expansion smaller than 10-6/K across the transition. This very strong discrepancy can be related either to (i) specific elastic properties of the gels, (ii) the dependance of T? on the pore size is drastically different of what could be expected.

  19. Carbon XANES Data from Six Aerogel Picokeystones Cut from the Top and Bottom Sides of the Stardust Comet Sample Tray

    NASA Technical Reports Server (NTRS)

    Wirick, S.; Flynn, G. J.; Frank, D.; Sandford, S. A.; Zolensky, M. E.; Tsou, P.; Peltzer, C.; Jacobsen, C.

    2009-01-01

    Great care and a large effort was made to minimize the amount of organic matter contained within the flight aerogel used to collect Comet 81P/Wild 2 samples. Even so, by the very nature of the production process and silica aerogel s affinity for volatile organics keeping silica aerogel free from organics is a monumental task. Silica aerogel from three production batches was flown on the Stardust sample return mission. All 3 types had layered densities varying from 5mg/ml to 50 mg/ml where the densest aerogel was farthest away from the collection area. A 2 step gelation process was used to make the flight aerogel and organics used in this process were tetraethylorthosilicate, ethanol and acetonitrile. Both ammonium hydroxide and nitric acid were also used in the aerogel production process. The flight aerogel was baked at JPL at 300 C for 72 hours, most of the baking was done at atmosphere but twice a day the oven was pumped to 10 torr for hour [1]. After the aerogel was baked it was stored in a nitrogen purged cabinet until flight time. One aerogel cell was located in the SRC away from any sample collection area as a witness to possible contamination from out gassing of the space craft, re-entry gases and any other organic encounter. This aerogel was aerogel used in the interstellar collection sample tray and is the least dense of the 3 batches of aerogel flown. Organics found in the witness tile include organics containing Si-CH3 bonds, amines and PAHS. Besides organic contamination, hot spots of calcium were reported in the flight aerogel. Carbonates have been detected in comet 81P/Wild2 samples . During preflight analyses, no technique was used to analyze for carbonates in aerogel. To determine if the carbonates found in 81P/Wild2 samples were from the comet, it is necessary to analyze the flight aerogel for carbonate as well as for organics.

  20. Characterization of three fibrous insulations for potential HTGR application

    SciTech Connect

    Selle, J. E.

    1980-11-01

    Three fibrous insulation materials manufactured by Babcock and Wilcox were characterized for possible use as HTGR core thermal insulations. These materials (Unifelt 3000 board, Unifelt 2600 board, and Kaowool blanket) were characterized by spectrographic analysis, x-ray diffractometry, scanning electron microscopy, ignition studies and bulk density measurements, resilience tests, helium permeation tests, and compressive stress-strain tests. Of these properties, resilience is the most important for determining acceptability of material for HTGR use. The arbitrary resilience acceptability criterion is 90% or greater after 20 h at 816/sup 0/C (1500/sup 0/F). Based on the resilience test, the Unifelt 3000 was acceptable, the Unifelt 2600 was marginal, and the Kaowool was unacceptable.

  1. A comparison of mechanical properties and scaling law relationships for silica aerogels and their organic counterparts

    SciTech Connect

    Pekala, R.W.; Hrubesh, L.W.; Tillotson, T.M.; Alviso, C.T.; Poco, J.F.; LeMay, J.D.

    1990-08-01

    Aerogels are a special class of open-cell foams derived from the supercritical extraction of highly crosslinked, inorganic or organic gels. The resultant materials have ultrafine cell/pore sizes (< 100 nm), high surface areas (350--1000m{sup 2}/g), and a microstructure composed of interconnected colloidal-like particles or polymeric chains with characteristic diameters of 10 nm. TEM and SAXS show that this microstructure is sensitive to variations in processing conditions that influence crosslinking chemistry and growth processes prior to gelation. Traditional silica aerogels are prepared via the hydrolysis and condensation of tetramethoxy silane (TMOS) or tetraethoxy silane (TEOS). Factors such as pH and the (H{sub 2}O)/(TMOS) ratio affect the microstructure of the dried aerogel. It is generally accepted that polymeric' silica aerogels result from acid catalysis while colloidal'silica aerogels result from base catalysis. Recently, Hrubesh and Tillotson developed a new condensed silica' procedure for obtaining silica aerogels with densities as low as 0.004g/cc, i.e. only 3{times} the density of air. Organic aerogels are formed from the aqueous, polycondensation of (1) resorcinol/formaldehyde or (2) melamine/formaldehyde. The microstructure of the resorcinol-formaldehyde (RF) aerogels is dictated by the amount of base catalyst used in the sol-gel polymerization. In addition, these materials can be pyrolyzed in an inert atmosphere to form vitreous carbon aerogels. Melamine- formaldehyde (MF) aerogels that are both colorless and transparent are only formed under acidic conditions (i.e. pH = 1--2). In this paper, the microstructural dependence and scaling law relationships for the compressive modulus of silica, carbon, RF, and MF aerogels will be discussed in detail. 17 refs., 1 fig.

  2. Aerogel dust collection for in situ mass spectrometry analysis

    NASA Astrophysics Data System (ADS)

    Jones, S. M.; Anderson, M. S.; Davies, A. G.; Kirby, J. P.; Burchell, M. J.; Cole, M. J.

    2015-02-01

    The current technique for conducting in situ mass spectroscopic analysis of dust around extraterrestrial bodies is to have the dust impact a solid plate and analyze the atoms and molecular fragments resulting from the high speed impact. Due to the fact that the kinetic energy from the impact is converted primarily to thermal energy, much of the organic compounds present in the dust may be significantly altered or destroyed. To avoid this problem, aerogel could be used to capture the dust grains, largely intact, maintaining the integrity of the organic compounds in the interior of the dust grains. To demonstrate that organic molecules, present as minor components of silica particles, would survive hypervelocity capture in aerogel and can then be analyzed with mass spectrometry, several light gas gun impact tests and analyses were conducted. Fine particles containing polycyclic aromatic hydrocarbons (PAHs) were captured in aerogel at 5.5 km s-1. The flow of metastable helium from a Direct Analysis Real Time (DART) source was used to desorb and ionize the organics, which were then analyzed with a mass spectrometer. The PAHs were detected and identified by the DART-MS, demonstrating that this method could be used on future flight instruments.

  3. Lunar and Planetary Science XXXV: Interplanetary Dust and Aerogel

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Contents include the following: Isotopically Primitive Interplanetary Dust Particles of Cometary Origin: Evidence from Nitrogen Isotopic Compositions. The Solar Nebula s First Accretionary Particles (FAPs) Are They Preserved in Collected Interplanetary Dust Samples? On the Origin of GEMS. An Analytical SuperSTEM for Extraterrestrial Materials Research. Sub-Micrometer Scale Minor Element Mapping in Interplanetary Dust Particles: A Test for Stratospheric Contamination. First Report of Taenite in an Asteroidal Interplanetary Dust Particle: Flash-heating Simulates Nebular Dust Evolution. FTIR Analyses of IDPs: Comparison with the InfraRed Spectra of the Interstellar Medium. Mineralogical Study of Hydrated IDPs: X-Ray Diffraction and Transmission Electron Microscopy. Focused Ion Beam Recovery and Analysis of Interplanetary Dust Particles (IDPs) and Stardust Analogues. Technique for Concentration of Carbonaceous Material from Aerogel Collectors Using HF-Vapor Etching. Synchrotron X-Ray Analysis of Captured Particle Residue in Aerogel. In-Situ Analyses of Earth Orbital Grains Trapped in Aerogel, Using Synchrotron X-Ray Microfluorescence Techniques. Igneous Rims on Micrometeorites and the Sizes of Chondrules in Main Belt Asteroids.

  4. Surface Plasmon Resonance Evaluation of Colloidal Metal Aerogel Filters

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

    Surface plasmon resonance imaging has in the past been applied to the characterization of thin films. In this study we apply the surface plasmon technique not to determine macroscopic spatial variations but rather to determine average microscopic information. Specifically, we deduce the dielectric properties of the surrounding gel matrix and information concerning the dynamics of the gelation process from the visible absorption characteristics of colloidal metal nanoparticles contained in aerogel pores. We have fabricated aerogels containing gold and silver nanoparticles. Because the dielectric constant of the metal particles is linked to that of the host matrix at the surface plasmon resonance, any change 'in the dielectric constant of the material surrounding the metal nanoparticles results in a shift in the surface plasmon wavelength. During gelation the surface plasmon resonance shifts to the red as the average or effective dielectric constant of the matrix increases. Conversely, formation of an aerogel or xerogel through supercritical extraction or evaporation of the solvent produces a blue shift in the resonance indicating a decrease in the dielectric constant of the matrix. From the magnitude of this shift we deduce the average fraction of air and of silica in contact with the metal particles. The surface area of metal available for catalytic gas reaction may thus be determined.

  5. A Solid breeder tokamak blanket designed for failure mode operation

    E-print Network

    Chen, Franklin Fun Kun

    1977-01-01

    The objective of this study was to evaluate a new concept for a Tokamak type fusion reactor blanket. The design was based on using a packed bed of lithium aluminate as the breeding material with helium gas cooling. The ...

  6. Outdoor high voltage polymeric insulators

    Microsoft Academic Search

    R. Hackam

    1998-01-01

    Composite polymeric insulators are increasingly being accepted by the traditionally cautious electric utilities worldwide. They currently represent about 70% of installed new high voltage insulators in North America. The tremendous growth in the applications of non-ceramic insulators is due to their advantages over the traditional ceramic and glass insulators. However, because polymeric insulators are relatively new the expected lifetime is

  7. Helium-cooled lithium compound suspension blanket concept for ITER

    Microsoft Academic Search

    Y. Gohar; C. C. Baker; H. Attaya; M. Billone; R. C. Clemmer; P. A. Finn; A. Hassanein; C. E. Johnson; S. Majumdar; R. F. Mattas

    1989-01-01

    This blanket concept uses a dilute suspension of fine solid breeder particles (LiâO, LiAlOâ, or LiâSiOâ) in a carrier gas (He) as the coolant and the tritium breeding stream. A small fraction of this stream is processed outside the reactor for tritium recovery. The blanket consists of a beryllium multiplier and carbon\\/steel reflector. A steel clad is used for all

  8. Conceptual design of tritium breeding blanket for INTOR

    Microsoft Academic Search

    G. D. Morgan; D. A. Bowers; M. J. Delaney; A. E. Hartman; R. G. Clemmer; M. A. Abdou; P. A. Finn; J. Jung; B. Misra; D. L. Smith

    1981-01-01

    The paper describes the U.S. reference design for the tritium breeding blanket for INTOR. Details of the blanket conceptual mechanical design are presented, together with a discussion of thermal, structural, and mechanical aspects and the rationale for selection of key design features. The INTOR design was required to use a solid tritium breeding compound, LiâSiOâ; a solid lead neutron multiplier;

  9. Helium-cooled lithiuim compound suspension blanket concept for ITER

    SciTech Connect

    Gohar, Y.; Baker, C.C.; Attaya, H.; Billone, M.; Clemmer, R.C.; Finn, P.A.; Hassanein, A.; Johnson, C.E.; Majumdar, S.; Mattas, R.F.

    1988-08-01

    This blanket concept uses a dilute suspension of fine solid breeder particles (Li/sub 2/O, LiAlO/sub 2/, or Li/sub 4/SiO/sub 4/) in a carrier gas (He) as the coolant and the tritium breeding stream. A small fraction of this stream is processed outside the reactor for tritium recovery. The blanket consists of a beryllium multiplier and carbon/steel reflector. A steel clad is used for all materials. A carbon reflector is employed to reduce the beryllium thickness used in the blanket for a specific tritium breeding ratio. The breeder particle size has to exceed few microns (greater than or equal to2 microns) to avoid sticking problems on the cold surfaces of the heat exchanger. The helium gas pressure is in the range of 2 to 3 MPa to carry the blanket and the heat exchanger loop. The solid breeder concentration in the helium stream is 1 to 5 volume percent. A high lithium-6 enrichment is used to produce a high tritium breeding ratio and to reduce the breeder concentration in the helium gas. At a lithium-6 enrichment of 90%, the local tritium breeding ratio is 2.03 based on a one-dimensional poloidal model. The total thickness of the helium stream is only 4 cm out of the 50 cm total blanket thickness. The blanket uses a 35 cm of beryllium for neutron multiplication. A simple multi-layer design is employed where the blanket sector has the helium coolant flowing in the poloidal direction. The blanket concept has several unique advantages which are very beneficial for fusion reactors including ITER. 10 refs., 2 tabs.

  10. Helium-cooled lithiuim compound suspension blanket concept for ITER

    Microsoft Academic Search

    Y. Gohar; C. C. Baker; H. Attaya; M. Billone; R. C. Clemmer; P. A. Finn; A. Hassanein; C. E. Johnson; S. Majumdar; R. F. Mattas

    1988-01-01

    This blanket concept uses a dilute suspension of fine solid breeder particles (LiâO, LiAlOâ, or LiâSiOâ) in a carrier gas (He) as the coolant and the tritium breeding stream. A small fraction of this stream is processed outside the reactor for tritium recovery. The blanket consists of a beryllium multiplier and carbon\\/steel reflector. A steel clad is used for all

  11. Evaluation of organic moderator/coolants for fusion breeder blankets

    SciTech Connect

    Romero, J.B.

    1980-03-01

    Organic coolants have several attractive features for fusion breeder blanket design. Their apparent compatibility with lithium and their ideal physical and nuclear properties allows straight-forward, high performance designs. Radiolytic damage can be reduced to about the same order as comparable fission systems by using multiplier/stripper blanket designs. Tritium recovery from the organic should be straightforward, but additional data is needed to make a better assessment of the economics of the process.

  12. Transient thermal and dynamic stresses in strongback-design blankets

    SciTech Connect

    Majumdar, S.

    1994-06-01

    Transient thermal stresses of the first wall are compared for strongback-design blankets that contain stainless steel, ferritic steel, or a vanadium alloy as structural materials. Transient dynamics stresses due to plasma disruptions are computed on a parametric basis. Disruption loading characteristics, for which transient effects are important, are identified. Also explored are the relative merits of supporting the blanket at the top versus the bottom from the standpoint of dynamic stresses.

  13. Multilayer Insulation Material Guidelines

    NASA Technical Reports Server (NTRS)

    Finckenor, M. M.; Dooling, D.

    1999-01-01

    Multilayer Insulation Material Guidelines provides data on multilayer insulation materials used by previous spacecraft such as Spacelab and the Long-Duration Exposure Facility and outlines other concerns. The data presented in the document are presented for information only. They can be used as guidelines for multilayer insulation design for future spacecraft provided the thermal requirements of each new design and the environmental effects on these materials are taken into account.

  14. Measuring Wall Insulation

    NASA Astrophysics Data System (ADS)

    Parks, Beth; Kurkel, Kevin; Zranchev, Amanda; Brown, Clayton

    2011-03-01

    Currently, the only way for homeowners to learn about the effectiveness of their home insulation is to hire an energy auditor. This difficulty deters homeowners from taking action to improve energy efficiency. We have developed a simple device to measure wall insulation by measuring the temperature difference between the wall surface and the interior air. This device is effective in diagnosing cases of low insulation.

  15. Metal-insulator transitions

    Microsoft Academic Search

    Masatoshi Imada; Atsushi Fujimori; Yoshinori Tokura

    1998-01-01

    Metal-insulator transitions are accompanied by huge resistivity changes, even over tens of orders of magnitude, and are widely observed in condensed-matter systems. This article presents the observations and current understanding of the metal-insulator transition with a pedagogical introduction to the subject. Especially important are the transitions driven by correlation effects associated with the electron-electron interaction. The insulating phase caused by

  16. Topological insulators and superconductors

    Microsoft Academic Search

    Xiao-Liang Qi; Shou-Cheng Zhang

    2010-01-01

    Topological insulators are new states of quantum matter which can not be\\u000aadiabatically connected to conventional insulators and semiconductors. They are\\u000acharacterized by a full insulating gap in the bulk and gapless edge or surface\\u000astates which are protected by time-reversal symmetry. These topological\\u000amaterials have been theoretically predicted and experimentally observed in a\\u000avariety of systems, including HgTe quantum

  17. A Simple Holographic Insulator

    E-print Network

    Eric Mefford; Gary T. Horowitz

    2014-07-11

    We present a simple holographic model of an insulator. Unlike most previous holographic insulators, the zero temperature infrared geometry is completely nonsingular. Both the low temperature DC conductivity and the optical conductivity at zero temperature satisfy power laws with the same exponent, given by the scaling dimension of an operator in the IR. Changing a parameter in the model converts it from an insulator to a conductor with a standard Drude peak.

  18. Lotus lithium-lead fusion blanket concept for neutronics experiments

    SciTech Connect

    Azam, S. (Inst. de Genie Atomique Ecole Polytechnique Federale de Lausanne CH-1015 Lausanne (CH)); Kumar, A. (Univ. of California at Los Angeles, Mechanical, Aerospace, and Nuclear Engineering Dept., Los Angeles, CA (US))

    1990-05-01

    The objective of the LOTUS experimental program, is to perform various integral neutronics measurements like neutron spectrometry, activation, and tritium breeding ratio (TBR) on fusion reactor blanket concepts. The first blanket concept studied at the LOTUS facility was the fission-suppressed type. Investigations of pure fusion blanket concepts constitute a logical continuation of this program., The new LOTUS fusion blanket concept employs a eutectic of lithium and lead, for example, 17L-83Pb, and lithium-metal as tritium breeders. The blanket consists of a first wall of low-activation ferritic steel, followed by zones of 17Li-83Pb, {sup 6}Li, and a reflector made of graphite or silicon carbide (SiC). The choice of structural material for each zone is based on its compatibility with the primary zonal component. Vanadium alloy (V-15 Cr-5 Ti), low-activation ferritic steel (Fe-11 Cr-2.5 W-0.3 V-0.15 C), and the same vanadium alloy were retained for 17Li-83Pb, {sup 6}Li, and graphite or SiC zones, respectively. This paper reports on one-dimensional ANISN calculations carried out for the optimization of the blanket dimensions.

  19. Alternator insulation evaluation tests

    NASA Technical Reports Server (NTRS)

    Penn, W. B.; Schaefer, R. F.; Balke, R. L.

    1972-01-01

    Tests were conducted to predict the remaining electrical insulation life of a 60 KW homopolar inductor alternator following completion of NASA turbo-alternator endurance tests for SNAP-8 space electrical power systems application. The insulation quality was established for two alternators following completion of these tests. A step-temperature aging test procedure was developed for insulation life prediction and applied to one of the two alternators. Armature winding insulation life of over 80,000 hours for an average winding temperature of 248 degrees C was predicted using the developed procedure.

  20. Topological crystalline insulator nanostructures.

    PubMed

    Shen, Jie; Cha, Judy J

    2014-11-01

    Topological crystalline insulators are topological insulators whose surface states are protected by the crystalline symmetry, instead of the time reversal symmetry. Similar to the first generation of three-dimensional topological insulators such as Bi?Se? and Bi?Te?, topological crystalline insulators also possess surface states with exotic electronic properties such as spin-momentum locking and Dirac dispersion. Experimentally verified topological crystalline insulators to date are SnTe, Pb?-xSnxSe, and Pb?-xSnxTe. Because topological protection comes from the crystal symmetry, magnetic impurities or in-plane magnetic fields are not expected to open a gap in the surface states in topological crystalline insulators. Additionally, because they have a cubic structure instead of a layered structure, branched structures or strong coupling with other materials for large proximity effects are possible, which are difficult with layered Bi?Se? and Bi?Te?. Thus, additional fundamental phenomena inaccessible in three-dimensional topological insulators can be pursued. In this review, topological crystalline insulator SnTe nanostructures will be discussed. For comparison, experimental results based on SnTe thin films will be covered. Surface state properties of topological crystalline insulators will be discussed briefly. PMID:25350386

  1. Light scattering studies of UV-catalyzed gel and aerogel structure

    Microsoft Academic Search

    Arlon J Hunt; Michael R Ayers

    1998-01-01

    The skeletal structure of aerogel is determined before, during, and after the gel is formed. Supercritical drying of aerogel largely preserves the pore structure that is determined near the time of gelation. To better understand gel-formation mechanisms, measurements of the time evolution of light scattering in a series of gels prepared without conventional acid or base catalysis were conducted. Ultraviolet

  2. Starch-based aerogels: airy materials from amylose-sodium palmitate inclusion complexes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aerogels are a class of interesting low density porous materials prepared by replacing the water phase contained within a hydrogel with a gas phase while maintaining the three dimensional network structure of the gel. The investigation of starch and hydrocolloid-based aerogels has received attentio...

  3. Optofluidic waveguides written in hydrophobic silica aerogels with a femtosecond laser

    NASA Astrophysics Data System (ADS)

    Yalizay, B.; Morova, Y.; Ozbakir, Y.; Jonas, A.; Erkey, C.; Kiraz, A.; Akturk, S.

    2015-02-01

    We present a new method to form liquid-core optofluidic waveguides inside hydrophobic silica aerogels. Due to their unique material properties, aerogels are very attractive for a wide variety of applications; however, it is very challenging to process them with traditional methods such as milling, drilling, or cutting because of their fragile structure. Therefore, there is a need to develop alternative processes for formation of complex structures within the aerogels without damaging the material. In our study, we used focused femtosecond laser pulses for high-precision ablation of hydrophobic silica aerogels. During the ablation, we directed the laser beam with a galvo-mirror system and, subsequently, focused the beam through a scanning lens on the surface of bulk aerogel which was placed on a three-axis translation stage. We succeeded in obtaining high-quality linear microchannels inside aerogel monoliths by synchronizing the motion of the galvo-mirror scanner and the translation stage. Upon ablation, we created multimode liquid-core optical waveguides by filling the empty channels inside low-refractive index aerogel blocks with highrefractive index ethylene glycol. In order to demonstrate light guiding and measure optical attenuation of these waveguides, we coupled light into the waveguides with an optical fiber and measured the intensity of transmitted light as a function of the propagation distance inside the channel. The measured propagation losses of 9.9 dB/cm demonstrate the potential of aerogel-based waveguides for efficient routing of light in optofluidic lightwave circuits.

  4. Rapid Extraction of Dust Impact Tracks from Silica Aerogel by Ultrasonic Micro-blades

    Microsoft Academic Search

    H Ishii; G Graham; A T Kearsley; P G Grant; C J Snead; J P Bradley

    2005-01-01

    In January 2006, NASA's Stardust Mission will return with its valuable cargo of cometary dust particles, the first brought back to Earth, captured at hypervelocity speeds in silica aerogel collectors. Aerogel, a proven capture medium, is also a candidate for future sample return missions and low-earth orbit (LEO) deployments. Critical to the science return of Stardust and future missions using

  5. Rapid extraction of dust impact tracks from silica aerogel by ultrasonic microblades

    Microsoft Academic Search

    H. A. Ishii; G. A. Graham; A. T. Kearsley; P. G. Grant; C. J. Snead; J. P. Bradley

    2005-01-01

    In January 2006, NASA's Stardust mission will return with its valuable cargo of the first cometary dust particles captured at hypervelocity speeds in silica aerogel collectors and brought back to Earth. Aerogel, a proven capture medium, is also a candidate for future sample return missions and low-Earth orbit (LEO) deployments. Critical to the science return of Stardust as well as

  6. Making flexible magnetic aerogels and stiff magnetic nanopaper using cellulose nanofibrils as templates

    Microsoft Academic Search

    R. T. Olsson; M. A. S. Azizi Samir; G. Salazar-Alvarez; L. Belova; V. Ström; L. A. Berglund; O. Ikkala; J. Nogués; U. W. Gedde

    2010-01-01

    Nanostructured biological materials inspire the creation of materials with tunable mechanical properties. Strong cellulose nanofibrils derived from bacteria or wood can form ductile or tough networks that are suitable as functional materials. Here, we show that freeze-dried bacterial cellulose nanofibril aerogels can be used as templates for making lightweight porous magnetic aerogels, which can be compacted into a stiff magnetic

  7. Impedance spectroscopic studies of sol–gel derived subcritically dried silica aerogels

    Microsoft Academic Search

    Aji A Anappara; S Rajeshkumar; P Mukundan; P. R. S Warrier; Swapankumar Ghosh; K. G. K Warrier

    2004-01-01

    The surface-hydration, dehydration and dehydroxylation and their dependence on the electrical properties of the silica aerogel have been investigated using electrochemical impedance spectroscopy. In equilibrium with the atmosphere, the aerogel exhibits strong sorption of water from the environment, but was found to be mainly due to physisorption. The mobile species responsible for electrical conduction was traced out as protons and

  8. Gas insulated transmission line with insulators having field controlling recesses

    DOEpatents

    Cookson, Alan H. (Pittsburgh, PA); Pederson, Bjorn O. (Chelmsford, MA)

    1984-01-01

    A gas insulated transmission line having a novel insulator for supporting an inner conductor concentrically within an outer sheath. The insulator has a recess contiguous with the periphery of one of the outer and inner conductors. The recess is disposed to a depth equal to an optimum gap for the dielectric insulating fluid used for the high voltage insulation or alternately disposed to a large depth so as to reduce the field at the critical conductor/insulator interface.

  9. APT Blanket System Loss-of-Helium-Gas Accident Based on Initial Conceptual Design - Helium Supply Rupture into Blanket Module

    SciTech Connect

    Hamm, L.L.

    1998-10-07

    The model results are used to determine if beam power shutdown is necessary (or not) as a result of the LOHGA accident to maintain the blanket system well below any of the thermal-hydraulic constraints imposed on the design. The results also provide boundary conditions to the detailed bin model to study the detailed temperature response of the hot blanket module structure. The results for these two cases are documented in the report.

  10. Tailoring of Boehmite-Derived Aluminosilicate Aerogel Structure and Properties: Influence of Ti Addition

    NASA Technical Reports Server (NTRS)

    Hurwitz, Frances I.; Guo, Haiquan; Sheets, Erik J.; Miller, Derek R.; Newlin, Katy N.

    2010-01-01

    Aluminosilicate aerogels offer potential for extremely low thermal conductivities at temperatures greater than 900 C, beyond where silica aerogels reach their upper temperature limits. Aerogels have been synthesized at various Al:Si ratios, including mullite compositions, using Boehmite (AlOOH) as the Al source, and tetraethoxy orthosilicate as the Si precursor. The Boehmite-derived aerogels are found to form by a self-assembly process of AlOOH crystallites, with Si-O groups on the surface of an alumina skeleton. Morphology, surface area and pore size varies with the crystallite size of the starting Boehmite powder, as well as with synthesis parameters. Ternary systems, including Al-Si-Ti aerogels incorporating a soluble Ti precursor, are possible with careful control of pH. The addition of Ti influences sol viscosity, gelation time pore structure and pore size distribution, as well as phase formation on heat treatment.

  11. Tanpopo cosmic dust collector: Silica aerogel production and bacterial DNA contamination analysis

    E-print Network

    Tabata, Makoto; Yokobori, Shin-ichi; Kawai, Hideyuki; Takahashi, Jun-ichi; Yano, Hajime; Yamagishi, Akihiko

    2011-01-01

    Hydrophobic silica aerogels with ultra-low densities have been designed and developed as cosmic dust capture media for the Tanpopo mission which is proposed to be carried out on the International Space Station. Glass particles as a simulated cosmic dust with 30 \\mu m in diameter and 2.4 g/cm^3 in density were successfully captured by the novel aerogel at a velocity of 6 km/s. Background levels of contaminated DNA in the ultra-low density aerogel were lower than the detection limit of a polymerase chain reaction assay. These results show that the manufactured aerogel has good performance as a cosmic dust collector and sufficient quality in respect of DNA contamination. The aerogel is feasible for the biological analyses of captured cosmic dust particles in the astrobiological studies.

  12. X-ray radiographic technique for measuring density uniformity of silica aerogel

    E-print Network

    Tabata, Makoto; Adachi, Ichiro; Morita, Takeshi; Nishikawa, Keiko; 10.1016/j.nima.2012.09.001

    2012-01-01

    This paper proposes a new X-ray radiographic technique for measuring density uniformity of silica aerogels used as radiator in proximity-focusing ring-imaging Cherenkov detectors. To obtain high performance in a large-area detector, a key characteristic of radiator is the density (i.e. refractive index) uniformity of an individual aerogel monolith. At a refractive index of n = 1.05, our requirement for the refractive index uniformity in the transverse plane direction of an aerogel tile is |\\delta (n - 1)/(n - 1)| aerogels from a trial production and that of Panasonic products (SP-50) as a reference, and to confirm they have sufficient density uniformity within \\pm 1% along the transverse plane direction. The measurement results show that the proposed technique can quantitatively estimate the density uniformity of aerogels.

  13. A Fluorescent Aerogel for Capture and Identification of Interplanetary and Interstellar Dust

    NASA Technical Reports Server (NTRS)

    Dominguez, Gerardo; Westphal, Andrew J.; Phillips, Mark L. F.; Jones, Steven M.

    2003-01-01

    Aerogels are extremely low-density solids whose superiority as capturing media for hypervelocity (v > 0.5 km/s) grains has been well established. A prominent example is the use of silica aerogel as the collecting medium for cometary and interstellar grains on NASA s Stardust mission. Aerogel collectors have been deployed in low-earth orbit, but severe background from anthropogenic orbital debris has so far prevented the identification of more than a handful of interplanetary particles. No interstellar particles have been identified so far. Since they are on hyperbolic orbits, extraterrestrial particles are faster than orbital debris, so could in principle be identified on that basis, but existing aerogels give little information on impact velocity. With this in mind, we have developed a novel calorimetric aerogel which passively records the kinetic energy of captured hypervelocity particles.

  14. Effects of processing conditions on the physical and electrochemical properties of carbon aerogel composites

    SciTech Connect

    Tran, T.D.; Lenz, D.; Kinoshita, K.; Droege, M.

    1998-07-01

    The carbon aerogel/carbon paper composites have physical properties similar to those of monolithic carbon aerogels but do not require supercritical extraction during fabrication. The resorcinol-formaldehyde based carbon aerogel phase is intertwined between the fibers of a commercial carbon paper. The resulting composites have variable densities (0.4--0.6 g/cc), high surface areas (300--600 m{sup 2}/g), and controllable pore sizes and pore distribution. The effects of the resorcinol-formaldehyde concentrations (50--70{degree} w/v) and the pyrolysis temperature (600--1,050 C) were studied in an attempt to tailor the aerogel microstructure and properties. The composite physical properties and structure were analyzed by transmission electron microscopy and multipoint-BET analyses and related to electrochemical capacitive data in 5M KOH. These thin carbon aerogel/carbon paper composite electrodes are used in experiments with electrochemical double-layer capacitors and capacitive deionization.

  15. Aerogels from unaltered bacterial cellulose: application of scCO2 drying for the preparation of shaped, ultra-lightweight cellulosic aerogels.

    PubMed

    Liebner, Falk; Haimer, Emmerich; Wendland, Martin; Neouze, Marie-Alexandra; Schlufter, Kerstin; Miethe, Peter; Heinze, Thomas; Potthast, Antje; Rosenau, Thomas

    2010-04-01

    Bacterial cellulose produced by the gram-negative bacterium Gluconacetobacter xylinum was found to be an excellent native starting material for preparing shaped ultra-lightweight cellulose aerogels. The procedure comprises thorough washing and sterilization of the aquogel, quantitative solvent exchange and subsequent drying with supercritical carbon dioxide at 40 degrees C and 100 bar. The average density of the obtained dry cellulose aerogels is only about 8 mg x cm(-3) which is comparable to the most lightweight silica aerogels and distinctly lower than all values for cellulosic aerogels obtained from plant cellulose so far. SEM, ESEM and nitrogen adsorption experiments at 77 K reveal an open-porous network structure that consists of a comparatively high percentage of large mesopores and smaller macropores. PMID:20166232

  16. Insulation Fact Sheet.

    ERIC Educational Resources Information Center

    Conservation and Renewable Energy Inquiry and Referral Service (DOE), Silver Spring, MD.

    Heating and cooling account for 50-70% of the energy consumed in the average American home. Heating water accounts for another 20%. A poorly insulated home loses much of this energy, causing drafty rooms and high energy bills. This fact sheet discusses how to determine if your home needs more insulation, the additional thermal resistance (called…

  17. Topological Anderson Insulator

    Microsoft Academic Search

    Jian Li; Rui-Lin Chu; J. K. Jain; Shun-Qing Shen

    2009-01-01

    Disorder plays an important role in two dimensions, and is responsible for striking phenomena such as metal-insulator transition and the integral and fractional quantum Hall effects. In this Letter, we investigate the role of disorder in the context of the recently discovered topological insulator, which possesses a pair of helical edge states with opposing spins moving in opposite directions and

  18. Insulators and Conductors

    NSDL National Science Digital Library

    IEEE

    2014-05-22

    In this activity, learners explore the concept of conducting or insulating electricity. Learners test different everyday materials to determine if the materials are conductors or insulators of electricity. Learners work in teams to test their predictions about each material and then compare results and discuss findings.

  19. Zirconia-based aerogels via hydrolysis of salts and alkoxides: the influence of the synthesis procedures on the properties of the aerogels.

    PubMed

    Schäfer, Helmut; Brandt, Susanne; Milow, Barbara; Ichilmann, Sachar; Steinhart, Martin; Ratke, Lorenz

    2013-09-01

    This contribution aims at evaluating different synthesis procedures leading to zirconia-based aerogels. A series of undoped and yttrium-doped zirconia aerogels have been prepared via hydrolysis and condensation reaction of different alkoxy- and different inorganic salt-based precursors followed by supercritical drying. Well-established but deleterious zirconium n-propoxide (TPOZ) or zirconium n-butoxide (TBOZ) were used as metal precursors in combination with acids like nitric acid and acetic acid as auxiliary agent for the generation of non-yttrium stabilized zirconia aerogels. Yttrium-stabilized zirconia aerogels as well as pure zirconia aerogels were obtained by the salt route starting from ZrCl4 and crosslinking agents like propylene oxide or acetylacetone. The characteristics of the products were analyzed by nitrogen adsorption measurements, electron microscopy, and X-ray scattering. It turned out that with respect to all relevant properties of the aerogels as well as the practicability of the synthesis procedures, approaches based on inexpensive non-toxic salt precursors are the methods of choice. The salt-based approaches allow not only for low-cost, easy-to-handle synthesis procedures with realizable gelation times of less than 60?seconds, but also delivered the products with the highest surface area (449?m(2) ?g(-1) for ZrCl4) within this series of syntheses. PMID:23801587

  20. Mott-insulator dynamics

    SciTech Connect

    Lundh, Emil [Department of Physics, Umeaa University, 901 87 Umeaa (Sweden)

    2011-09-15

    The hydrodynamics of a lattice Bose gas in a time-dependent external potential is studied in a mean-field approximation. The conditions under which a Mott insulating region can melt, and the local density can adjust to the new potential, are determined. In the case of a suddenly switched potential, it is found that the Mott insulator stays insulating and the density will not adjust if the switch is too abrupt. This comes about because too rapid currents result in Bloch oscillation-type current reversals. For a stirrer moved through a Mott insulating cloud, it is seen that only if the stirrer starts in a superfluid region and the velocity is comparable to the time scale set by the tunneling will the Mott insulator be affected.

  1. Dynamics insulation systems

    NASA Technical Reports Server (NTRS)

    Chen, W. E. W.; Hepler, W. A.; Yuan, S. W. K.; Frederking, T. H. K.

    1985-01-01

    Advanced dynamic insulation systems were analyzed from a thermodynamic point of view. A particular performance measure is proposed in order to characterize various insulations in a unique manner. This measure is related to a base quantity, the refrigeration power ratio. The latter is the minimum refrigeration power, for a particular dynamic insulation limit, to the actual reliquefaction power associated with cryoliquid boiloff. This ratio serves as reference quantity which is approximately constant for a specific ductless insulation at a chosen normal boiling point. Each real container with support structure, vent tube, and other transverse components requires a larger refrigeration power. The ratio of the actual experimental power to the theoretical value of the support-less system is a suitable measure of the entire insulation performance as far as parasitic heat leakage is concerned. The present characterization is illustrated using simple thermodynamic system examples including experiments with liquid nitrogen. Numerical values are presented and a comparison with liquid helium is given.

  2. Breakdown of organic insulators

    NASA Technical Reports Server (NTRS)

    Cuddihy, E. F.

    1983-01-01

    Solar cells and their associated electrical interconnects and leads were encapsulated in transparent elastomeric materials. Their purpose in a photovoltaic module, one of the most important for these elastomeric encapsulation materials, is to function as electrical insulation. This includes internal insulation between adjacent solar cells, between other encapsulated electrical parts, and between the total internal electrical circuitry and external metal frames, grounded areas, and module surfaces. Catastrophic electrical breakdown of the encapsulant insulation materials or electrical current through these materials or module edges to external locations can lead to module failure and can create hazards to humans. Electrical insulation stability, advanced elastomeric encapsulation materials are developed which are intended to be intrinsically free of in-situ ionic impurities, have ultralow water absorption, be weather-stable (UV, oxygen), and have high mechanical flexibility. Efforts to develop a method of assessing the life potential of organic insulation materials in photovoltaic modules are described.

  3. Thermal performance of gaseous-helium-purged tank-mounted multilayer insulation system during ground-hold and space-hold thermal cycling and exposure to water vapor

    NASA Technical Reports Server (NTRS)

    Sumner, I. E.

    1978-01-01

    An experimental investigation was conducted to determine (1) the ground-hold and space-hold thermal performance of a multilayer insulation (MLI) system mounted on a spherical, liquid-hydrogen propellant tank and (2) the degradation to the space-hold thermal performance of the insulation system that resulted from both thermal cycling and exposure to moisture. The propellant tank had a diameter of 1.39 meters (4.57ft). The MLI consisted of two blankets of insulation; each blanket contained 15 double-aluminized Mylar radiation shields separated by double silk net spacers. Nineteen tests simulating basic cryogenic spacecraft thermal (environmental) conditions were conducted. These tests typically included initial helium purge, liquid-hydrogen fill and ground-hold, ascent, space-hold, and repressurization. No significant degradation of the space-hold thermal performance due to thermal cycling was noted.

  4. Efficient optical materials based on fluorinated-polymeric silica aerogels

    NASA Astrophysics Data System (ADS)

    García, O.; Sastre, R.; Agua, D. del; Costela, A.; García-Moreno, I.; Roig, A.

    2006-08-01

    New hybrid solid-state dye laser materials based on highly porous silica aerogels saturated with laser dye pyrromethene 567 dissolved in copolymers of methyl methacrylate with different volumetric proportion of different fluorinated monomers have been synthesized. Remarkable lasing efficiency of up 32% was recorded with a highly stable laser operation with no sign of degradation in the laser output after 100,000 pump pulses in the same position under transversal pumping with 532 nm at 30 Hz repetition rate. These results make very promising the approach used in this work to enhance the lasing action of dye laser doped hybrid solid-state materials.

  5. Thermal Performance of Cryogenic Multilayer Insulation at Various Layer Spacings

    NASA Technical Reports Server (NTRS)

    Johnson, Wesley Louis

    2010-01-01

    Multilayer insulation (MLI) has been shown to be the best performing cryogenic insulation system at high vacuum (less that 10 (exp 3) torr), and is widely used on spaceflight vehicles. Over the past 50 years, many investigations into MLI have yielded a general understanding of the many variables that are associated with MLI. MLI has been shown to be a function of variables such as warm boundary temperature, the number of reflector layers, and the spacer material in between reflectors, the interstitial gas pressure and the interstitial gas. Since the conduction between reflectors increases with the thickness of the spacer material, yet the radiation heat transfer is inversely proportional to the number of layers, it stands to reason that the thermal performance of MLI is a function of the number of layers per thickness, or layer density. Empirical equations that were derived based on some of the early tests showed that the conduction term was proportional to the layer density to a power. This power depended on the material combination and was determined by empirical test data. Many authors have graphically shown such optimal layer density, but none have provided any data at such low densities, or any method of determining this density. Keller, Cunnington, and Glassford showed MLI thermal performance as a function of layer density of high layer densities, but they didn't show a minimal layer density or any data below the supposed optimal layer density. However, it was recently discovered that by manipulating the derived empirical equations and taking a derivative with respect to layer density yields a solution for on optimal layer density. Various manufacturers have begun manufacturing MLI at densities below the optimal density. They began this based on the theory that increasing the distance between layers lowered the conductive heat transfer and they had no limitations on volume. By modifying the circumference of these blankets, the layer density can easily be varied. The simplest method of determining the thermal performance of MLI at cryogenic temperature is by boil-off calorimetry. Several blankets were procured and tested at various layer densities at the Cryogenics Test Laboratory at Kennedy Space Center. The densities that the blankets were tested over covered a wide range of layer densities including the analytical minimum. Several of the blankets were tested at the same insulation thickness while changing the layer density (thus a different number of reflector layers). Optimizing the layer density of multilayer insulation systems for heat transfer would remove a layer density from the complex method of designing such insulation systems. Additional testing was performed at various warm boundary temperatures and pressures. The testing and analysis was performed to simplify the analysis of cryogenic thermal insulation systems. This research was funded by the National Aeronautics and Space Administration's Exploration Technology Development Program's Cryogenic Fluid Management Project

  6. Helium-cooled lithium compound suspension blanket concept for ITER

    SciTech Connect

    Gohar, Y.; Baker, C.C.; Attaya, H.; Billone, M.; Clemmer, R.C.; Finn, P.A.; Hassanein, A.; Johnson, C.E.; Majumdar, S.; Mattas, R.F.

    1989-03-01

    This blanket concept uses a dilute suspension of fine solid breeder particles (Li/sub 2/O, LiAlO/sub 2/, or Li/sub 4/SiO/sub 4/) in a carrier gas (He) as the coolant and the tritium breeding stream. A small fraction of this stream is processed outside the reactor for tritium recovery. The blanket consists of a beryllium multiplier and carbon/steel reflector. A steel clad is used for all materials. A carbon reflector is employed to reduce the the beryllium thickness used in the blanket for a specific tritium breeding ratio. The breeder particle size has to exceed a few microns (greater than or equal to 2 microns) to avoid sticking problems on the cold surfaces of the heat exchanger. The helium gas pressure is in the range of 2 - 3 MPa to carry the solid breeder particles through the blanket and the heat exchanger loop. The solid breeder concentration in the helium stream is 1 to 5 volume percent. A high lithium-6 enrichment is used to produce a high tritium breeding ratio and to reduce the breeder concentration in the helium gas. The main features, key technical issues, and design analyses of this blanket concept are summarized in this paper.

  7. Inorganic hollow nanotube aerogels by atomic layer deposition onto native nanocellulose templates.

    PubMed

    Korhonen, Juuso T; Hiekkataipale, Panu; Malm, Jari; Karppinen, Maarit; Ikkala, Olli; Ras, Robin H A

    2011-03-22

    Hollow nano-objects have raised interest in applications such as sensing, encapsulation, and drug-release. Here we report on a new class of porous materials, namely inorganic nanotube aerogels that, unlike other aerogels, have a framework consisting of inorganic hollow nanotubes. First we show a preparation method for titanium dioxide, zinc oxide, and aluminum oxide nanotube aerogels based on atomic layer deposition (ALD) on biological nanofibrillar aerogel templates, that is, nanofibrillated cellulose (NFC), also called microfibrillated cellulose (MFC) or nanocellulose. The aerogel templates are prepared from nanocellulose hydrogels either by freeze-drying in liquid nitrogen or liquid propane or by supercritical drying, and they consist of a highly porous percolating network of cellulose nanofibrils. They can be prepared as films on substrates or as freestanding objects. We show that, in contrast to freeze-drying, supercritical drying produces nanocellulose aerogels without major interfibrillar aggregation even in thick films. Uniform oxide layers are readily deposited by ALD onto the fibrils leading to organic-inorganic core-shell nanofibers. We further demonstrate that calcination at 450 °C removes the organic core leading to purely inorganic self-supporting aerogels consisting of hollow nanotubular networks. They can also be dispersed by grinding, for example, in ethanol to create a slurry of inorganic hollow nanotubes, which in turn can be deposited to form a porous film. Finally we demonstrate the use of a titanium dioxide nanotube network as a resistive humidity sensor with a fast response. PMID:21361349

  8. Ultralow Density, Monolithic WS2, MoS2, and MoS2/Graphene Aerogels.

    PubMed

    Worsley, Marcus A; Shin, Swanee J; Merrill, Matthew D; Lenhardt, Jeremy; Nelson, Art J; Woo, Leta Y; Gash, Alex E; Baumann, Theodore F; Orme, Christine A

    2015-05-26

    We describe the synthesis and characterization of monolithic, ultralow density WS2 and MoS2 aerogels, as well as a high surface area MoS2/graphene hybrid aerogel. The monolithic WS2 and MoS2 aerogels are prepared via thermal decomposition of freeze-dried ammonium thio-molybdate (ATM) and ammonium thio-tungstate (ATT) solutions, respectively. The densities of the pure dichalcogenide aerogels represent 0.4% and 0.5% of full density MoS2 and WS2, respectively, and can be tailored by simply changing the initial ATM or ATT concentrations. Similar processing in the presence of the graphene aerogel results in a hybrid structure with MoS2 sheets conformally coating the graphene scaffold. This layered motif produces a ?50 wt % MoS2 aerogel with BET surface area of ?700 m(2)/g and an electrical conductivity of 112 S/m. The MoS2/graphene aerogel shows promising results as a hydrogen evolution reaction catalyst with low onset potential (?100 mV) and high current density (100 mA/cm(2) at 260 mV). PMID:25858296

  9. Effect on mass transference phenomena by textural change inside monolithic carbon aerogels

    NASA Astrophysics Data System (ADS)

    Chejne, F.; Camargo-Trillos, D.; Pabón, E.; Carrasco-Marin, F.

    2015-01-01

    The effects on mass transference phenomena due textural changes of monolithic carbon aerogels were studied by hexane adsorption. The monolithic carbon aerogels were prepared after carbonization of the organic aerogels obtained by resorcinol-formaldehyde polymerization, using p-toluenesulfonic acid (acid-catalyst) and sodium carbonate catalysts (basic-catalyst). Internal texture was modified by CO2 activation. The characterization by gas adsorption showed that the monolithic carbon aerogels presents a bi-modal pore size distribution with presence of both microporous and mesoporous. It was shown that the activation process of monolithic carbon aerogels increases their micropore volume bigger than the other one acid-catalyst aerogel. The mesopores volume in the carbon aerogels plays an important role on mass transport mechanism. The samples with presence of significant mesopore volume present a lower height of mass transfer zone than others less mesopore volume; therefore better efficiency of adsorption in mass transfer zone in dynamic adsorption. The breakthrough curve methodology proposed in this work has allowed finding a relationship between the structural parameters and dynamic adsorption variables, which opens new approaches for measuring textural parameters of material.

  10. Iron-oxide aerogel and xerogel catalyst formulations: Characterization by 57Fe Mössbauer and XAFS spectroscopies

    NASA Astrophysics Data System (ADS)

    Huggins, Frank E.; Bali, Sumit; Huffman, Gerald P.; Eyring, Edward M.

    2010-06-01

    Iron in various iron-oxide aerogel and xerogel catalyst formulations (?85% Fe 2O 3; ?10% K, Co, Cu, or Pd) developed for possible use in Fischer-Tropsch synthesis (FTS) or the water-gas-shift (WGS) reaction has been examined by 57Fe Mössbauer spectroscopy. The seventeen samples consisted of both as-prepared and calcined aerogels and xerogels and their products after use as catalysts for FTS or the WGS reaction. Complementary XAFS spectra were obtained on the occurrence of the secondary elements in some of the same materials. A broad, slightly asymmetric, two-peak Mössbauer spectrum was obtained from the different as-prepared and calcined catalyst formulations in the majority of cases. Such spectra could only be satisfactorily fit with three quadrupole doublet components, but no systematic trends in the isomer shift and quadrupole splitting parameters and area ratios of the individual components could be discerned that reflected variations in the composition or preparation of the aerogel or xerogel materials. However, significant reductions were noted in the Mössbauer effective thickness (recoilless absorption effect per unit mass of iron) parameter, ?eff/ g, determined at room temperature, for aerogels and xerogels compared to bulk iron oxides, reflecting the openness and lack of rigidity of the aerogel and xerogel structures. Mössbauer measurements for two aerogels over the range from 15 to 292 K confirmed the greatly diminished nature of this parameter at room temperature. Major increases in the effective thickness parameter were observed when the open structure of the aerogel or xerogel collapsed during calcination resulting in the formation of iron oxides (hematite, spinel ferrite). Similar structural changes were indicated by increases in this parameter after use of iron-oxide aerogels as catalysts for FTS or the WGS reaction, during which the iron-oxide aerogel was converted to a mixture of nonstoichiometric magnetite and the Hägg carbide, ?-Fe 5C 2, or nonstoichiometric magnetite, respectively.

  11. Microsphere Insulation Panels

    NASA Technical Reports Server (NTRS)

    Mohling, R.; Allen, M.; Baumgartner, R.

    2006-01-01

    Microsphere insulation panels (MIPs) have been developed as lightweight, longlasting replacements for the foam and vacuum-jacketed systems heretofore used for thermally insulating cryogenic vessels and transfer ducts. The microsphere core material of a typical MIP consists of hollow glass bubbles, which have a combination of advantageous mechanical, chemical, and thermal-insulation properties heretofore available only separately in different materials. In particular, a core filling of glass microspheres has high crush strength and low density, is noncombustible, and performs well in soft vacuum.

  12. Internal insulation system development

    NASA Technical Reports Server (NTRS)

    Gille, J. P.

    1973-01-01

    The development of an internal insulation system for cryogenic liquids is described. The insulation system is based on a gas layer concept in which capillary or surface tension effects are used to maintain a stable gas layer within a cellular core structure between the tank wall and the contained cryogen. In this work, a 1.8 meter diameter tank was insulated and tested with liquid hydrogen. Ability to withstand cycling of the aluminum tank wall to 450 K was a design and test condition.

  13. Cryogenic insulation development

    NASA Technical Reports Server (NTRS)

    Leonhard, K. E.

    1972-01-01

    Multilayer insulations for long term cryogenic storage are described. The development effort resulted in an insulation concept using lightweight radiation shields, separated by low conductive Dacron fiber tufts. The insulation is usually referred to as Superfloc. The fiber tufts are arranged in a triangular pattern and stand about .040 in. above the radiation shield base. Thermal and structural evaluation of Superfloc indicated that this material is a strong candidate for the development of high performance thermal protection systems because of its high strength, purge gas evacuation capability during boost, its density control and easy application to a tank.

  14. Milli's Insulation Investigation

    NSDL National Science Digital Library

    2013-07-08

    In this activity on page 2 of the PDF, learners test different materials to find out which is the best insulator. Learners use aluminum foil, newspaper, plastic wrap, and wax paper to insulate ice cubes and compare the melting rate of each ice cube. Use this activity to introduce learners to heat transfer (conduction) and insulation materials. Safety notes: Adult supervision required. Do not eat or drink any of the materials in this activity. Follow Milli's safety tips, which are listed on the left hand side of page 2.

  15. Outdoor HV composite polymeric insulators

    Microsoft Academic Search

    R. Hackam

    1999-01-01

    HV composite polymeric insulators are being accepted increasingly for use in outdoor installations by the traditionally cautious electric power utilities worldwide. They currently represent ~60 to 70% of newly installed HV insulators in North America. The tremendous growth in the applications of non-ceramic composite insulators is due to their advantages over the traditional ceramic and glass insulators. These include light

  16. Page 1 of 3 Blanket and First Wall Science Priority and Funding Requirements,

    E-print Network

    extraction, tritium fuel sustainability, and radiation shielding. The Blanket and FW: - is a single; engineering scaling and statistical reliability methodology) Situation Analysis The blanket and first and resolve scientific feasibility issues for fusion power extraction and tritium sustainability - limited

  17. 19 CFR 19.6 - Deposits, withdrawals, blanket permits to withdraw and sealing requirements.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Deposits, withdrawals, blanket permits to withdraw and sealing requirements. 19.6 Section 19.6 Customs Duties... Deposits, withdrawals, blanket permits to withdraw and sealing requirements. (a)(1) Deposit in...

  18. Knudsen-Hydrodynamic Crossover in Liquid 3He in High Porosity Aerogel

    E-print Network

    Takeuchi, H; Nagai, K; Choi, H C; Moon, B H; Masuhara, N; Meisel, M W; Lee, Y; Mulders, N

    2012-01-01

    We present a combined experimental and theoretical study of the drag force acting on a high porosity aerogel immersed in liquid ${}^3$He and its effect on sound propagation. The drag force is characterized by the Knudsen number, which is defined as the ratio of the quasiparticle mean free path to the radius of an aerogel strand. Evidence of the Knudsen-hydrodynamic crossover is clearly demonstrated by a drastic change in the temperature dependence of ultrasound attenuation in 98% porosity aerogel. Our theoretical analysis shows that the frictional sound damping caused by the drag force is governed by distinct laws in the two regimes, providing excellent agreement with the experimental observation.

  19. Prediction of thermal resistances and heat conduction of carbon nanotube aerogels in various permeated gases

    NASA Astrophysics Data System (ADS)

    Gong, Feng; Tam, Yong Siang; Nguyen, Son T.; Duong, Hai M.

    2015-05-01

    Heat conduction in single-walled carbon nanotube (SWNT) aerogels is investigated by an off-lattice Monte Carlo method. Thermal boundary resistances (TBRs) between the SWNT and four permeated gases of argon, nitrogen, neon and hydrogen are reported from fitting simulation results with experimental data. It is found that the TBRs between the SWNT and the permeated gases decrease with larger gas molecular masses. Effects of volume fractions and complex morphologies of SWNTs on thermal conductivities of SWNT aerogels are also quantified. The effective thermal conductivities of SWNT aerogels increase with the larger volume fraction, the greater length and the smaller diameter of the SWNTs.

  20. A new scanning electron microscopy approach to image aerogels at the nanoscale

    NASA Astrophysics Data System (ADS)

    Solá, F.; Hurwitz, F.; Yang, J.

    2011-04-01

    A new scanning electron microscopy (SEM) technique to image poor electrically conductive aerogels is presented. The process can be performed by non-expert SEM users. We showed that negative charging effects on aerogels can be minimized significantly by inserting dry nitrogen gas close to the region of interest. The process involves the local recombination of accumulated negative charges with positive ions generated from ionization processes. This new technique made possible the acquisition of images of aerogels with pores down to approximately 3 nm in diameter using a positively biased Everhart-Thornley (ET) detector.

  1. A new scanning electron microscopy approach to image aerogels at the nanoscale.

    PubMed

    Solá, F; Hurwitz, F; Yang, J

    2011-04-29

    A new scanning electron microscopy (SEM) technique to image poor electrically conductive aerogels is presented. The process can be performed by non-expert SEM users. We showed that negative charging effects on aerogels can be minimized significantly by inserting dry nitrogen gas close to the region of interest. The process involves the local recombination of accumulated negative charges with positive ions generated from ionization processes. This new technique made possible the acquisition of images of aerogels with pores down to approximately 3 nm in diameter using a positively biased Everhart-Thornley (ET) detector. PMID:21411927

  2. Direct formation of aerogels by sol-gel polymerizations of alkoxysilanes in supercritical carbon dioxide

    SciTech Connect

    Loy, D.A.; Yamanaka, A.; Carpenter, J.P. [Sandia National Labs., Albuquerque, NM (United States); [Univ. of California, Irvine, CA (United States)] [and others

    1997-12-31

    Sol-gel polymerization of alkoxysilanes in supercritical carbon dioxide (SCCD) was used to directly prepare aerogels. Polymerizations of tetramethoxysilane (TMOS) and 1,4-bis(triethoxysilyl)benzene (BESP) were performed by dissolving the monomers and formic acid in supercritical carbon dioxide (SCCD). Monolithic gels were obtained in under 12 hours. The silica and polysilsesquioxane gels were readily dried to afford aerogels by slowly venting the SCCD. The aerogels were high surface area mesoporous materials that were characterized by solid state NMR, SEM, TEM, and gas sorption porosimetry.

  3. Carbon nanofiber aerogels for emergent cleanup of oil spillage and chemical leakage under harsh conditions

    PubMed Central

    Wu, Zhen-Yu; Li, Chao; Liang, Hai-Wei; Zhang, Yu-Ning; Wang, Xin; Chen, Jia-Fu; Yu, Shu-Hong

    2014-01-01

    To address oil spillage and chemical leakage accidents, the development of efficient sorbent materials is of global importance for environment and water source protection. Here we report on a new type of carbon nanofiber (CNF) aerogels as efficient sorbents for oil uptake with high sorption capacity and excellent recyclability. Importantly, the oil uptake ability of the CNF aerogels can be maintained over a wide temperature range, from liquid nitrogen temperature up to ca. 400°C, making them suitable for oil cleanup under harsh conditions. The outstanding sorption performance of CNF aerogels is associated with their unique physical properties, such as low density, high porosity, excellent mechanical stability, high hydrophobicity and superoleophilicity. PMID:24518262

  4. Highly stable solid state dye lasers based on polymer-filled nanoporous silica aerogels

    NASA Astrophysics Data System (ADS)

    Costela, Angel; Garcia-Moreno, Inmaculada; Gomez, Clara; Garcia, Olga; Sastre, Roberto; Molins, Elies; Roig, Anna

    2004-09-01

    New hybrid matrices based on silica aerogels obtained under supercritical conditions, a highly porous material with porosityt up to 90%, have been synthesized. The open porous network of the aerogel was saturated with pyrromethene dyes solved in organic mooners, and polymerization took place inside of the silica structure. The resulting polymer filled nanoporous aerogels, cast in the form of cylindrical monoliths, were used as gain media in solid-state dye lasers. Under the demanding conditions of tightly focused transversal pumping with 532 nm, 5 mJ pulses at 10 Hz repetition rate, highly photostable laser emission was obtained.

  5. Effective three-dimensional superhydrophobic aerogel-coated channel for high efficiency water-droplet transport

    NASA Astrophysics Data System (ADS)

    Kim, Aeree; Kim, Hyungmo; Lee, Chan; Kim, Joonwon

    2014-02-01

    Three-dimensional superhydrophobic surfaces have been used effectively to optimize droplet transport efficiency in diverse fluidic systems. However, the fabrication methods for superhydrophobic surfaces applicable to fluidic devices usually involve complicated process. Herein, we report a simple but effective method of fabricating a superhydrophobic surface using organically modified silica aerogel. Superhydrophobic aerogel thin film having highly porous micro/nanostructured surface with methyl groups was realized inside a 3D channel by coating it. To demonstrate that the aerogel-coated surface effectively facilitates movement of water droplets, the droplet-based flow characteristics regarding the triple line were conducted.

  6. Enhancement of Magnetization in Liquid 3He at Aerogel Interface

    NASA Astrophysics Data System (ADS)

    Fukui, A.; Kondo, K.; Kato, C.; Obara, K.; Yano, H.; Ishikawa, O.; Hata, T.

    2013-05-01

    A novel feature of condensate state in liquid 3He is predicted theoretically, which consists of spin triplet s-wave Cooper pairs (Higashitani et al. in J. Low. Temp. Phys. 155:83-97, 2009). Such a spin triplet s-wave state will appear inside aerogel near the surface boundary contacting with superfluid 3He-B, and the enhancement of magnetization due to s-wave state is theoretically expected (Nagato et al. in J. Phys. Soc. Jpn. 78:123603, 2009; Higashitani et al. in Phys. Rev. B 85:024524, 2012). In order to detect this proximity effect, we made the interface in columnar glass tube which coated with 2.5 layer 4He, and set a saddle shape NMR coil very near the interface. At 7 bar, we found that superfluidity in liquid 3He inside aerogel never occurred, even at considerably low temperatures. At 24 bar below T/ T c =0.392, we observed no decrease of magnetization with decreasing temperatures. This phenomenon might be due to spin triplet s-wave Cooper pairs.

  7. The LHCb RICH silica aerogel performance with LHC data

    E-print Network

    Perego, D L

    2010-01-01

    In the LHCb detector at the Large Hadron Collider, powerful charged particle identification is performed by Ring Imaging Cherenkov (RICH) technology. In order to cover the full geometric acceptance and the wide momentum range (1-100 GeV/c), two detectors with three Cherenkov radiators have been designed and installed. In the medium (10-40 GeV/c) and high (30-100 GeV/c) momentum range, gas radiators are used (C4F10 and CF4 respectively). In the low momentum range (1 to a few GeV/c) pion/kaon/proton separation will be done with photons produced in solid silica aerogel. A set of 16 tiles, with the large transverse dimensions ever (20x20 cm$^2$) and nominal refractive index 1.03 have been produced. The tiles have excellent optical properties and homogeneity of refractive index within the tile of ~1%. The first data collected at LHC are used to understand the behaviour of the RICH: preliminary results will be presented and discussed on the performance of silica aerogel and of the gas radiators C4F10 and CF4.

  8. Deep Bed Adsorption Testing using Silver-Functionalized Aerogel

    SciTech Connect

    Nick Soelberg; Tony Watson

    2012-06-01

    Nuclear fission results in the production of fission products and activation products, some of which tend to be volatile during used fuel reprocessing and evolve in gaseous species into the reprocessing facility off-gas systems. Analyses have shown that I129, due to its radioactivity, high potential mobility in the environment, and high longevity (half life of 15.7 million years), can require control efficiencies of up to 1,000x or higher to meet regulatory emission limits. Two Aerogel sorption tests that have been performed this fiscal year. The maximum iodine decontamination factor (DF) was measured to be over 10,000, above the 1,000-10,000 target DF range. The mass transfer zone may be as short as 0.5 inches under the sorption conditions of the first test. Only a small fraction of the iodine sorbed on Bed 1 was desorbed during the purge periods. The silver-functionalized Aerogel appears to have potential to be a very effective and efficient iodine sorbent.

  9. Development of Improved Aerogels for Spacecraft Hypervelocity Capture

    NASA Technical Reports Server (NTRS)

    Lisse, C. M.; Cheng, A. F.; Chabot, N. L.; Dello Russo, N.; Satcher, J. H.; Zolensky, M. E.; Cintala, M. J.; Glavin, D. P.; Sandford, S. A.

    2008-01-01

    The highly successful NASA Discovery mission Stardust became the first mission to return samples to Earth from a known comet in January 2006 [1]. The samples were captured during a flyby of comet 81P/Wild2 using aerogel, a very low density, silica (SiO2)-based solid with a highly porous structure [2]. Currently, scientists around the world are studying the cometary particles returned by Stardust and reporting fascinating discoveries about the history of comets and the evolution of our solar system. Given the widely acknowledged success of the Stardust mission, additional comet sample return missions are attractive and competitive concepts for future NASA Discovery-class missions; in particular, additional comet sample return missions will allow the first laboratory studies to investigate the naturally occurring diversity among comets, a crucial scientific question for understanding not just the formation of comets but also the very nature of the early solar system. Though Stardust was highly successful, there are important lessons learned from the mission on which advances in aerogel technology can be based

  10. Experimental impacts into Teflon targets and LDEF thermal blankets

    NASA Astrophysics Data System (ADS)

    Hoerz, F.; Cintala, M. J.; Zolensky, M. E.; Bernhard, R. P.; See, T. H.

    1994-03-01

    The Long Duration Exposure Facility (LDEF) exposed approximately 20 sq m of identical thermal protective blankets, predominantly on the Ultra-Heavy Cosmic Ray Experiment (UHCRE). Approximately 700 penetration holes greater than 300 micron in diameter were individually documented, while thousands of smaller penetrations and craters occurred in these blankets. As a result of their 5.7 year exposure and because they pointed into a variety of different directions relative to the orbital motion of the nonspinning LDEF platform, these blankets can reveal important dynamic aspects of the hypervelocity particle environment in near-earth orbit. The blankets were composed of an outer teflon layer (approximately 125 micron thick), followed by a vapor-deposited rear mirror of silver (less than 1000 A thick) that was backed with an organic binder and a thermal protective paint (approximately 50 to 75 micron thick), resulting in a cumulative thickness (T) of approximately 175 to 200 microns for the entire blanket. Many penetrations resulted in highly variable delaminations of the teflon/metal or metal/organic binder interfaces that manifest themselves as 'dark' halos or rings, because of subsequent oxidation of the exposed silver mirror. The variety of these dark albedo features is bewildering, ranging from totally absent, to broad halos, to sharp single or multiple rings. Over the past year experiments were conducted over a wide range of velocities (i.e., 1 to 7 km/s) to address velocity dependent aspects of cratering and penetrations of teflon targets. In addition, experiments were performed with real LDEF thermal blankets to duplicate the LDEF delaminations and to investigate a possible relationship of initial impact conditions on the wide variety of dark halo and ring features.

  11. Experimental impacts into Teflon targets and LDEF thermal blankets

    NASA Technical Reports Server (NTRS)

    Hoerz, F.; Cintala, M. J.; Zolensky, M. E.; Bernhard, R. P.; See, T. H.

    1994-01-01

    The Long Duration Exposure Facility (LDEF) exposed approximately 20 sq m of identical thermal protective blankets, predominantly on the Ultra-Heavy Cosmic Ray Experiment (UHCRE). Approximately 700 penetration holes greater than 300 micron in diameter were individually documented, while thousands of smaller penetrations and craters occurred in these blankets. As a result of their 5.7 year exposure and because they pointed into a variety of different directions relative to the orbital motion of the nonspinning LDEF platform, these blankets can reveal important dynamic aspects of the hypervelocity particle environment in near-earth orbit. The blankets were composed of an outer teflon layer (approximately 125 micron thick), followed by a vapor-deposited rear mirror of silver (less than 1000 A thick) that was backed with an organic binder and a thermal protective paint (approximately 50 to 75 micron thick), resulting in a cumulative thickness (T) of approximately 175 to 200 microns for the entire blanket. Many penetrations resulted in highly variable delaminations of the teflon/metal or metal/organic binder interfaces that manifest themselves as 'dark' halos or rings, because of subsequent oxidation of the exposed silver mirror. The variety of these dark albedo features is bewildering, ranging from totally absent, to broad halos, to sharp single or multiple rings. Over the past year experiments were conducted over a wide range of velocities (i.e., 1 to 7 km/s) to address velocity dependent aspects of cratering and penetrations of teflon targets. In addition, experiments were performed with real LDEF thermal blankets to duplicate the LDEF delaminations and to investigate a possible relationship of initial impact conditions on the wide variety of dark halo and ring features.

  12. Thermal performance of a modularized replaceable multilayer insulation system for a cryogenic stage

    NASA Technical Reports Server (NTRS)

    Knoll, R. H.

    1977-01-01

    A rugged modularized MLI system for a 2.23-meter-diameter (87.6-in.-diam) liquid hydrogen tank was designed, fabricated, and tested under simulated near-earth and deep-space environments. The two blankets of the system were each composed of 17 double-aluminized Mylar radiation shields separated by silk net. The unit area weight of the installed system was 1.54 kg/sqm (0.32 lb/sq ft). The overall average heat transferred into the insulated tank was 22.7 and 0.98 watts (77.4 and 3.3 Btu/hr) during simulated near-earth and deep-space testing, respectively. The near-earth result was only 2.6 times that predicted for an undisturbed insulation system (i.e., no seams or penetrations). Tests indicate that this insulation concept could be useful for a cryogenic space tug or orbit transfer vehicle application.

  13. Thermal Insulation Systems 

    E-print Network

    Stanley, T. F.

    1982-01-01

    Thermal insulation systems are receiving a high degree of attention in view of increasing energy cost. Industrial, commercial and residential energy users are all well aware of energy cost increases and great emphasis is being directed to energy...

  14. Compact gas insulated transformer

    NASA Astrophysics Data System (ADS)

    1984-01-01

    The development of design and manufacturing technologies is described. A transformer which is more efficient, more compact, lower in weight and audible sound, nonflammable, which does not rely upon mineral oil insulation, and which is compatible with the gas insulated electrical system of the future is designed. Design prototypes in the 50 MVA-345 kV range are to be tested. The program provides for economic, environmental, and systems application assessments of the emergent technologies.

  15. ASRM Case Insulation development

    Microsoft Academic Search

    W. F. S. Tam; M. Bell

    1993-01-01

    The ASRM Case Insulation Program used design of experiments to develop a high performance case insulation. The program traded-off more than thirty properties in areas of ablation performance, material properties, processibility, bonding\\/aging. Kevlar pulp was found to be the most significant factor. The low-molecular weight ethylene propylene diene monomer, EPDM was the second most significant factor. The curative was the

  16. Improved Sprayable Insulation

    NASA Technical Reports Server (NTRS)

    Hill, W. F.; Sharpe, M. H.; Lester, C. N.; Echols, Sherman; Simpson, W. G.; Lambert, J. D.; Norton, W. F.; Mclemore, J. P.; Patel, A. K.; Patel, S. V.; Shockney, C. H.; Adams, G. R.; Kelly, M. R.; White, W. T.

    1992-01-01

    MSA-2 and MSA-2A, two similar improved versions of Marshall sprayable ablator, insulating material developed at Marshall Space Flight Center to replace both sheets of cork and MSA-1. Suitable for use on large vehicles and structures exposed to fire or other sources of heat by design or accident. Ablative insulation turns into strong char when exposed to high temperature; highly desireable property in original spacecraft application and possibly in some terrestrial applications.

  17. Mineral Wool Insulation Binders

    Microsoft Academic Search

    Stefan Kowatsch

    2010-01-01

    \\u000a Mineral wool is considered the best known insulation type among the wide variety of insulation materials. There are three\\u000a types of mineral wool, and these consist of glass, stone (rock), and slag wool. The overall manufacturing processes, along\\u000a with features such as specifications and characteristics for each of these types, as well as the role of the binder within\\u000a the

  18. Insulator for laser housing

    DOEpatents

    Duncan, David B. (Auburn, CA)

    1992-01-01

    The present invention provides a heat-resistant electrical insulator adapted for joining laser housing portions, which insulator comprises: an annulus; a channel in the annulus traversing the circumference and length of the housing; at least two ports, each communicating with the channel and an outer surface of the housing; and an attachment for securely attaching each end of the annulus to a laser housing member.

  19. Modular Dual Coolant Pb-17Li Blanket Design For ARIES-CS Compact Stellarator Power Plant

    E-print Network

    Raffray, A. René

    Modular Dual Coolant Pb-17Li Blanket Design For ARIES-CS Compact Stellarator Power Plant X.R. Wanga of the modular dual coolant blanket concept. The overall layout of the blanket module including the He coolant maintenance schemes include both a field-period-based maintenance approach and a modular maintenance approach

  20. Nucleonic design for a compact tokamak fusion reactor blanket and shield

    Microsoft Academic Search

    E. T. Cheng; C. W. Maynard; W. F. Vogelsang; A. C. Klein

    1979-01-01

    The nucleonic design for the NUWMAK compact tokamak fusion reactor blanket and shield is presented. The critical design requirements for a reactor blanket and shield are: (1) adequate tritium breeding ratio, (2) high blanket energy multiplication, (3) adequate magnet protection, and (4) low radioactivity. The magnet protection is particularly essential in the inner region of the torus close to the

  1. Test blanket modules in ITER: An overview on proposed designs and required DEMO-relevant materials

    E-print Network

    Abdou, Mohamed

    Test blanket modules in ITER: An overview on proposed designs and required DEMO-relevant materials, Russian Federation Abstract Within the framework of the ITER Test Blanket Working Group, the ITER Parties have made several proposals for test blanket modules to be tested in ITER from the first day of H

  2. Growth rate reduction of the curvature-driven flute instability by plasma blanket line tying

    Microsoft Academic Search

    David Segal

    1983-01-01

    The effect of an annular, line-tied blanket, on the curvature-driven flute in a magnetic mirror is considered. The blanket is assumed to be line tied to a thermoionically emitting annular end plate. Reduction of the flute growth rate is computed as function of Larmor radius, blanket radius, and axial plasma conductance through either an external plasma or mirror sheath. It

  3. Fire tests on insulation for aluminum tank cars: an evaluation of glass-fiber, ceramic-fiber, and mineral-fiber materials in torch-fire and pool-fire environments. Final report

    Microsoft Academic Search

    1987-01-01

    Tests were conducted at the Transportation Test Center to determine the vulnerability to fire of aluminum tank cars designed to transport hazardous materials under pressure when the aluminum was protected by three types of insulation. Glass, mineral, and ceramic fiber blankets, each covering a speciment of aluminum plate commonly used in tank car construction, were subjected to standard torch-fire and

  4. Silica aerogel for capturing intact interplanetary dust particles for the tanpopo experiment.

    PubMed

    Tabata, Makoto; Yano, Hajime; Kawai, Hideyuki; Imai, Eiichi; Kawaguchi, Yuko; Hashimoto, Hirofumi; Yamagishi, Akihiko

    2015-06-01

    In this paper, we report the progress in developing a silica-aerogel-based cosmic dust capture panel for use in the Tanpopo experiment on the International Space Station (ISS). Previous studies revealed that ultralow-density silica aerogel tiles, comprising two layers with densities of 0.01 and 0.03 g/cm(3) developed using our production technique, were suitable for achieving the scientific objectives of the astrobiological mission. A special density configuration (i.e., box framing) aerogel with a holder was designed to construct the capture panels. Qualification tests for an engineering model of the capture panel as an instrument aboard the ISS were successful. Sixty box-framing aerogel tiles were manufactured in a contamination-controlled environment. PMID:25794831

  5. Silica Aerogel for Capturing Intact Interplanetary Dust Particles for the Tanpopo Experiment

    NASA Astrophysics Data System (ADS)

    Tabata, Makoto; Yano, Hajime; Kawai, Hideyuki; Imai, Eiichi; Kawaguchi, Yuko; Hashimoto, Hirofumi; Yamagishi, Akihiko

    2015-06-01

    In this paper, we report the progress in developing a silica-aerogel-based cosmic dust capture panel for use in the Tanpopo experiment on the International Space Station (ISS). Previous studies revealed that ultralow-density silica aerogel tiles, comprising two layers with densities of 0.01 and 0.03 g/cm3 developed using our production technique, were suitable for achieving the scientific objectives of the astrobiological mission. A special density configuration (i.e., box framing) aerogel with a holder was designed to construct the capture panels. Qualification tests for an engineering model of the capture panel as an instrument aboard the ISS were successful. Sixty box-framing aerogel tiles were manufactured in a contamination-controlled environment.

  6. Silica aerogel for capturing intact interplanetary dust particles for the Tanpopo experiment

    E-print Network

    Tabata, Makoto; Kawai, Hideyuki; Imai, Eiichi; Kawaguchi, Yuko; Hashimoto, Hirofumi; Yamagishi, Akihiko

    2015-01-01

    In this paper, we report the progress in developing a silica-aerogel-based cosmic dust capture panel for use in the Tanpopo experiment on the International Space Station (ISS). Previous studies revealed that ultralow-density silica aerogel tiles comprising two layers with densities of 0.01 and 0.03 g/cm$^3$ developed using our production technique were suitable for achieving the scientific objectives of the astrobiological mission. A special density configuration (i.e., box framing) aerogel with a holder was designed to construct the capture panels. Qualification tests for an engineering model of the capture panel as an instrument aboard the ISS were successful. Sixty box-framing aerogel tiles were manufactured in a contamination-controlled environment.

  7. Engineering carbon nanostructures : development of novel aerogel-nanotube composites and optimization techniques for nanotube growth

    E-print Network

    Steiner, Stephen Alan, III

    2006-01-01

    Carbon aerogels offer several unique advantages which make them ideal for evaluating a metal's ability to catalyze nanotube growth, including in situ carbothermic reduction of oxidized nanoparticles to their catalytic ...

  8. Liquid–solid phase transition of hydrogen and deuterium in silica aerogel

    SciTech Connect

    Van Cleve, E.; Worsley, M. A.; Kucheyev, S. O., E-mail: kucheyev@llnl.gov [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2014-10-28

    Behavior of hydrogen isotopes confined in disordered low-density nanoporous solids remains essentially unknown. Here, we use relaxation calorimetry to study freezing and melting of H{sub 2} and D{sub 2} in an ?85%-porous base-catalyzed silica aerogel. We find that liquid–solid transition temperatures of both isotopes inside the aerogel are depressed. The phase transition takes place over a wide temperature range of ?4?K and non-trivially depends on the liquid filling fraction, reflecting the broad pore size distribution in the aerogel. Undercooling is observed for both H{sub 2} and D{sub 2} confined inside the aerogel monolith. Results for H{sub 2} and D{sub 2} are extrapolated to tritium-containing hydrogens with the quantum law of corresponding states.

  9. Making flexible magnetic aerogels and stiff magnetic nanopaper using cellulose nanofibrils as templates

    NASA Astrophysics Data System (ADS)

    Olsson, R. T.; Azizi Samir, M. A. S.; Salazar-Alvarez, G.; Belova, L.; Ström, V.; Berglund, L. A.; Ikkala, O.; Nogués, J.; Gedde, U. W.

    2010-08-01

    Nanostructured biological materials inspire the creation of materials with tunable mechanical properties. Strong cellulose nanofibrils derived from bacteria or wood can form ductile or tough networks that are suitable as functional materials. Here, we show that freeze-dried bacterial cellulose nanofibril aerogels can be used as templates for making lightweight porous magnetic aerogels, which can be compacted into a stiff magnetic nanopaper. The 20-70-nm-thick cellulose nanofibrils act as templates for the non-agglomerated growth of ferromagnetic cobalt ferrite nanoparticles (diameter, 40-120 nm). Unlike solvent-swollen gels and ferrogels, our magnetic aerogel is dry, lightweight, porous (98%), flexible, and can be actuated by a small household magnet. Moreover, it can absorb water and release it upon compression. Owing to their flexibility, high porosity and surface area, these aerogels are expected to be useful in microfluidics devices and as electronic actuators.

  10. Drug release from nanoparticles embedded in four different nanofibrillar cellulose aerogels.

    PubMed

    Valo, Hanna; Arola, Suvi; Laaksonen, Päivi; Torkkeli, Mika; Peltonen, Leena; Linder, Markus B; Serimaa, Ritva; Kuga, Shigenori; Hirvonen, Jouni; Laaksonen, Timo

    2013-09-27

    Highly porous nanocellulose aerogels prepared by freeze-drying from various nanofibrillar cellulose (NFC) hydrogels are introduced as nanoparticle reservoirs for oral drug delivery systems. Here we show that beclomethasone dipropionate (BDP) nanoparticles coated with amphiphilic hydrophobin proteins can be well integrated into the NFC aerogels. NFCs from four different origins are introduced and compared to microcrystalline cellulose (MCC). The nanocellulose aerogel scaffolds made from red pepper (RC) and MCC release the drug immediately, while bacterial cellulose (BC), quince seed (QC) and TEMPO-oxidized birch cellulose-based (TC) aerogels show sustained drug release. Since the release of the drug is controlled by the structure and interactions between the nanoparticles and the cellulose matrix, modulation of the matrix formers enable a control of the drug release rate. These nanocomposite structures can be very useful in many pharmaceutical nanoparticle applications and open up new possibilities as carriers for controlled drug delivery. PMID:23500041

  11. Silica Aerogel for Capturing Intact Interplanetary Dust Particles for the Tanpopo Experiment

    NASA Astrophysics Data System (ADS)

    Tabata, Makoto; Yano, Hajime; Kawai, Hideyuki; Imai, Eiichi; Kawaguchi, Yuko; Hashimoto, Hirofumi; Yamagishi, Akihiko

    2015-03-01

    In this paper, we report the progress in developing a silica-aerogel-based cosmic dust capture panel for use in the Tanpopo experiment on the International Space Station (ISS). Previous studies revealed that ultralow-density silica aerogel tiles, comprising two layers with densities of 0.01 and 0.03 g/cm3 developed using our production technique, were suitable for achieving the scientific objectives of the astrobiological mission. A special density configuration (i.e., box framing) aerogel with a holder was designed to construct the capture panels. Qualification tests for an engineering model of the capture panel as an instrument aboard the ISS were successful. Sixty box-framing aerogel tiles were manufactured in a contamination-controlled environment.

  12. Versatile fabrication of magnetic carbon fiber aerogel applied for bidirectional oil-water separation

    NASA Astrophysics Data System (ADS)

    Li, Yong; Zhu, Xiaotao; Ge, Bo; Men, Xuehu; Li, Peilong; Zhang, Zhaozhu

    2015-06-01

    Fabricating functional materials that can solve environmental problems resulting from oil or organic solvent pollution is highly desired. However, expensive materials or complicated procedures and unidirectional oil-water separation hamper their applications. Herein, a magnetic superhydrophobic carbon fiber aerogel with high absorption capacity was developed by one-step pyrolysis of Fe(NO3)3-coated cotton in an argon atmosphere. The obtained aerogel can selectively collect oils from oil-polluted region by a magnet bar owing to its magnetic properties and achieves fast oil-water separation for its superhydrophobicity and superoleophilicity. Furthermore, the aerogel performs recyclable oil absorption capacity even after ten cycles of oil-water separation and bears organic solvent immersion. Importantly, the obtained aerogel turns to superhydrophilic and underwater superoleophobic after thermal treatment, allowing it as a promising and efficient material for bidirectional oil-water separation and organic contaminants removal.

  13. Cellulose aerogel regenerated from ionic liquid solution for immobilized metal affinity adsorption.

    PubMed

    Oshima, Tatsuya; Sakamoto, Toshihiko; Ohe, Kaoru; Baba, Yoshinari

    2014-03-15

    Surface morphology of cellulosic adsorbents is expected to influence the adsorption behavior of biomacromolecules. In the present study, cellulose aerogel regenerated from ionic liquid solution was prepared for use as a polymer support for protein adsorption. Iminodiacetic acid groups were introduced to the aerogel for immobilized metal affinity adsorption of proteins. A Cu(II)-immobilized iminodiacetic acid cellulose aerogel (Cu(II)-IDA-CA), which has a large specific surface area, showed a higher adsorption capacity than Cu(II)-immobilized iminodiacetic acid bacterial cellulose (Cu(II)-IDA-BC) and Cu(II)-immobilized iminodiacetic acid plant cellulose (Cu(II)-IDA-PC). In contrast, the Cu(II)-immobilized cellulosic adsorbents showed similar adsorption capacities for smaller amino acid and peptides. The results show that cellulose aerogels are useful as polymer supports with high protein adsorption capacities. PMID:24528701

  14. Highly effective removal of basic fuchsin from aqueous solutions by anionic polyacrylamide/graphene oxide aerogels.

    PubMed

    Yang, Xiaoxia; Li, Yanhui; Du, Qiuju; Sun, Jiankun; Chen, Long; Hu, Song; Wang, Zonghua; Xia, Yanzhi; Xia, Linhua

    2015-09-01

    Novel anionic polyacrylamide/graphene oxide aerogels were prepared by a freeze drying method and used to remove basic fuchsin from aqueous solutions. These aerogels were sponge-like solid with lightweight, fluffy and porous structure. The batch adsorption experiments were carried out to study the effect of various parameters, such as the solution pH, adsorbent dose, contact time and temperature on adsorption properties of basic fuchsin onto anionic polyacrylamide/graphene oxide aerogels. The kinetics of adsorption corresponded to the pseudo-second-order kinetic model. The Langmuir adsorption isotherm was suitable to describe the equilibrium adsorption process. The maximum adsorption capacity was up to 1034.3mg/g, which indicated that anionic polyacrylamide/graphene oxide aerogels were promising adsorbents for removing dyes pollutants from aqueous solution. PMID:25978557

  15. Purity and cleanness of aerogel as a cosmic dust capture medium

    NASA Technical Reports Server (NTRS)

    Tsou, P.; Fleming, R. H.; Lindley, P. M.; Craig, A. Y.; Blake, D.

    1994-01-01

    The capability for capturing micrometeoroids intact through laboratory simulations and in space in passive underdense silica aerogel offers a valuable tool for cosmic dust research. The integrity of the sample handling medium can substantially modify the integrity of the sample. Intact capture is a violent hypervelocity event: the integrity of the capturing medium can cause even greater modification of the sample. Doubts of the suitability of silica aerogel as a capture medium were raised at the 20th LPSC, and questions were raised again at the recent workshop on Particle Capture, Recovery, and Velocity Trajectory Measurement Technologies. Assessment of aerogel's volatile components and carbon contents have been made. We report the results of laboratory measurements of the purity and cleanliness of silica aerogel used for several Sample Return Experiments flown on the Get Away Special program.

  16. Structural characterization of intermediate species during synthesis of Al 2O 3-aerogels

    Microsoft Academic Search

    Ute Janosovits; Günter Ziegler; Uta Scharf; Alexander Wokaun

    1997-01-01

    Alumina sols in the system (Al(OC4H9sec)3\\/H2O\\/HNO3) were synthesized based on a well known method. Structural changes during sol–gel transition, aging of the gel and water–acetone exchange were studied, and the effect of these parameters on the structure and morphology of the aerogels was investigated. The alumina aerogels were prepared by supercritical drying with CO2. Structural changes during the various synthesis

  17. Effect of different chemical additives and heat-treatment on ambient pressure dried silica aerogels

    Microsoft Academic Search

    Ming-Long Liu; De-An Yang; Yuan-Fang Qu

    2010-01-01

    The experimental results on the physical and super-hydrophobic properties of the ambient pressure-dried silica aerogels doped with different chemical additives (CAs) and heat-treated at 350°C for 2 h in air are reported. N,N-dimethylformamide (DMF), glycerol (GLY) and ethylene glycol (EG) were doped as CAs to the tetraethyoxysiliane (TEOS) precursor prepared aerogels. The molar ratio of CAs\\/TEOS (G) was varied from

  18. Self-assembled ultralight three-dimensional polypyrrole aerogel for effective electromagnetic absorption

    NASA Astrophysics Data System (ADS)

    Xie, Aming; Wu, Fan; Sun, Mengxiao; Dai, Xiaoqing; Xu, Zhuanghu; Qiu, Yanyu; Wang, Yuan; Wang, Mingyang

    2015-06-01

    A facile self-assembled polymerization method has been used to form pyrrole to an ultralight three-dimensional (3D) polypyrrole (PPy) aerogel. It exhibits an effective electromagnetic absorption (EA) bandwidth (deeper than -10 dB), which was characterized as 6.2 GHz when the filler loading is only 7 wt. % in paraffin based composite. This 3D-PPy aerogel can be considered as a light weight, low adjunction, thin thickness, and high performance EA material.

  19. Enhancement of muonium emission rate from silica aerogel with a laser ablated surface

    E-print Network

    Beer, G A; Hirota, S; Ishida, K; Iwasaki, M; Kanda, S; Kawai, H; Kawamura, N; Kitamura, R; Lee, S; Marshall, W Lee G M; Mibe, T; Miyake, Y; Okada, S; Olchanski, K; Olin, A; Oishi, Y; Onishi, H; Otani, M; Saito, N; Shimomura, K; Strasser, P; Tabata, M; Tomono, D; Ueno, K; Yokoyama, K; Won, E

    2014-01-01

    Emission of muonium ($\\mu^+e^-$) atoms from a laser-processed aerogel surface into vacuum was studied for the first time. Laser ablation was used to create hole-like regions with diameter of about 270$~\\mu$m in a triangular pattern with hole separation in the range of 300--500$~\\mu$m. The emission probability for the laser-processed aerogel sample is at least eight times higher than for a uniform one.

  20. Effect of mixed Catalysts system on TEOS-based silica aerogels dried at ambient pressure

    Microsoft Academic Search

    Jyoti L. Gurav; Digambar Y. Nadargi; A. Venkateswara Rao

    2008-01-01

    In the present paper, the experimental results on the effect of mixed Catalysts system on the physical properties of the TEOS-based silica aerogels, are reported and discussed. The aerogels were produced by the single-step as well as two-step sol–gel process followed by atmospheric pressure drying. In the single-step process, only the NH4F was used as a catalyst, whereas in the

  1. Superior mechanical performance of highly porous, anisotropic nanocellulose-montmorillonite aerogels prepared by freeze casting.

    PubMed

    Donius, Amalie E; Liu, Andong; Berglund, Lars A; Wegst, Ulrike G K

    2014-09-01

    Directionally solidified nanofibrillated cellulose (NFC)-sodium-montmorillonite (MMT) composite aerogels with a honeycomb-like pore structure were compared with non-directionally frozen aerogels with equiaxed pore structure and identical composition and found to have superior functionalities. To explore structure-property correlations, three different aerogel compositions of 3wt% MMT, and 0.4wt%, 0.8wt%, and 1.2wt% NFC, respectively, were tested. Young?s modulus, compressive strength and toughness were found to increase with increasing NFC content for both architectures. The modulus increased from 25.8kPa to 386kPa for the isotropic and from 2.13MPa to 3.86MPa for the anisotropic aerogels, the compressive yield strength increased from 3.3kPa to 18.0kPa for the isotropic and from 32.3kPa to 52.5kPa for the anisotropic aerogels, and the toughness increased from 6.3kJ/m(3) to 24.1kJ/m(3) for the isotropic and from 22.9kJ/m(3) to 46.2kJ/m(3) for the anisotropic aerogels. The great range of properties, which can be achieved through compositional as well as architectural variations, makes these aerogels highly attractive for a large range of applications, for which either a specific composition, or a particular pore morphology, or both are required. Finally, because NFC is flammable, gasification experiments were performed, which revealed that the inclusion of MMT increased the heat endurance and shape retention functions of the aerogels dramatically up to 800°C while the mechanical properties were retained up to 300°C. PMID:24905177

  2. The Preservation of Cometary Organics in Stardust Aerogel

    NASA Astrophysics Data System (ADS)

    Clemett, Simon; Nakamura-Messenger, Keiko; Sandford, Scott; McKay, David

    It has been recognized for many years that the continuous global accretion of organic matter from comets and carbonaceous asteroids, over geological timescales, to the surfaces of both Earth and Mars may have played a significant role in the prebiotic chemical evolution of these planets [1]. The dominant mass fraction of accreted meteoritic material is in the form of interplanetary dust for which the current accretion rate is estimated at ˜ 40±20 Gg·yr-1 [2]. Our understanding of the organic matter present in interplanetary dust is, however, limited by the analytical challenges involved in the molecular analysis of heterogeneous micron sized particles. We have used the technique of ultrafast two-step laser mass spectrometry (µltra-L2 MS) to investigate the nature and distribution of the aromatic organic matter present in individual dust particles from comet P81/Wild 2 collected in aerogel by the STARDUST sample return mission [3]. Complex aromatic hydrocarbons have been detected in cometary particles entrained along multiple aerogel tracks. Although terrestrial contamination from the aerogel remains a concern, a substantial fraction is interpreted as indigenous. The spectral complexity is atypical of carbonaceous and ordinary chondrites. While simple fused ring polycyclic aromatic hydrocarbon (PAHs) such as naphthalene (C10 H8 ), acenaphthalene (C12 H8 ), phenanthrene (C14 H10 ) are present along with their homologous alkylation series (Ar-(CH2 )n -H) there are additionally many prominent odd-mass species present. These are consistent with several interleaved alkylation series of N-containing PAHS (NPAHs) in the form of nitriles (Ar-CN). These species may be related to the 2.3 & 4.6 µm 'XCN' adsorption features observed in the spectra of many young stellar objects and some comets, which is believed to be synthesized by ultraviolet and/or ion bombardment of precometary ices in circumstellar environments. The presence of organo-N species is of particular importance to the organic inventory of the the early Earth since its abiotic synthesis would have been extremely slow due to the difficulty in cleaving the N?N triple bond in the absence of biology. [1] Anders (1989) Nature 342, 255; [2] Love & Brownlee (1993) Science 262, 550; Clemett et al. MAPS (submited)

  3. Waveguide for microwave heating of solid lithium ceramic blankets

    Microsoft Academic Search

    R. L. Kustom; P. Fendley; J. Tidona

    1985-01-01

    The designers of solid lithium ceramic breeder blankets need to perform thermal hydraulic thermal mechanic tests without using neutrons to avoid activating the sample and to reduce the costs of such tests. It is desired to have uniform heating in the plane perpendicular to what would be the direction of emitted neutrons and an exponential decay of heat deposition in

  4. First-wall/blanket materials selection for STARFIRE tokamak reactor

    SciTech Connect

    Smith, D.L.; Mattas, R.F.; Clemmer, R.G.; Davis, J.W.

    1980-01-01

    The development of the reference STARFIRE first-wall/blanket design involved numerous trade-offs in the materials selection process for the breeding material, coolant structure, neutron multiplier, and reflector. The major parameters and properties that impact materials selection and design criteria are reviewed.

  5. Development of tritium breeding blankets for DT burning fusion reactors

    Microsoft Academic Search

    R. G. Clemmer

    1980-01-01

    Blanket tritium recovery and the performance of potentially viable tritium breeding materials under conditions anticipated in a DT fueled fusion reactor environment was studied. The existing physicochemical, thermophysical, and ceramographic data for candidate liquid and solid breeders are reviewed and appropriate operating conditions defined. It is shown that selection of a breeding material and an appropriate tritium recovery method can

  6. Accelerator driven production of tritium: target and blanket design 

    E-print Network

    Ragusa, Jean Concetto

    1996-01-01

    investigated. The target designs in the heterogeneous systems were 1 / liquid lead, and 2/ layers of solid lead plates cooled by heavy water. The tritium breeding blanket assemblies contained either lithium oxide or molten fluorine salt with or without UF4...

  7. Blast venting through blanket material in the HYLIFE ICF reactor

    Microsoft Academic Search

    J. C. Liu; P. F. Peterson; V. E. Schrock

    1992-01-01

    This work presents a numerical study of blast venting through various blanket configurations in the HYLIFE ICF reactor design. The study uses TSUNAMI -- a multi-dimensional, high-resolution, shock capturing code -- to predict the momentum exchange and gas dynamics for blast venting in complex geometries. In addition, the study presents conservative predictions of wall loading by gas shock and impulse

  8. Development of a lightweight carbon fibre reinforced solar array blanket

    Microsoft Academic Search

    I. Lydorf; D. Ruesch

    1978-01-01

    The design and testing of a lightweight, carbon fiber, reinforced solar array blanket applicable for Intelsat are reported. Consideration is given to the layout, packing density, and substrate and stiffener configurations. Testing procedures are outlined noting measurements of tensile strength and elongation, thermal expansion coefficients, proton and electron irradiation, and thermal cycling. Fabrication procedures are reviewed, noting both the manufacture

  9. Fluidized ejecta blankets on Mars - Estimate of material properties

    Microsoft Academic Search

    B. A. Ivanov; A. V. Pogoretsky; B. Murray

    1997-01-01

    Previous studies of fluidized ejecta blankets (FEB) around Martian craters assumed the model of hydrodynamic outflow of ejecta after deposition. We now use the Bingham rheology as a means to compare mass motions of various types. Bingham parameters (cohesion and viscosity) for the FEB material should be smaller than similar parameters for terrestrial dry rock avalanches but larger than for

  10. Accelerator driven production of tritium: target and blanket design

    E-print Network

    Ragusa, Jean Concetto

    1996-01-01

    investigated. The target designs in the heterogeneous systems were 1 / liquid lead, and 2/ layers of solid lead plates cooled by heavy water. The tritium breeding blanket assemblies contained either lithium oxide or molten fluorine salt with or without UF4...

  11. Neutronics Assessment of Molten Salt Breeding Blanket Design

    E-print Network

    1 Neutronics Assessment of Molten Salt Breeding Blanket Design Options Mohamed Sawan Fusion adequate tritium breeding and shielding for VV and magnet Larger margins are considered to account flow channel required to cool it #12;5 Tritium Breeding Potential If neutron coverage for double null

  12. Enhanced plasma current collection from weakly conducting solar array blankets

    Microsoft Academic Search

    G. Barry Hillard

    1993-01-01

    Among the solar cell technologies to be tested in space as part of the Solar Array Module Plasma Interactions Experiment (SAMPIE) will be the Advanced Photovoltaic Solar Array (APSA). Several prototype twelve cell coupons were built for NASA using different blanket materials and mounting techniques. The first conforms to the baseline design for APSA which calls for the cells to

  13. Thermal performance of fiberglass and cellulose attic insulations

    SciTech Connect

    Wilkes, K.E.; Childs, P.W.

    1992-10-01

    A series of experiments has been completed on the thermal performance of fiberglass and cellulose attic insulations under winter conditions using an attic test module in a guarded hot box facility. Experiments with one type of loose-fill fiberglass insulation showed that the thermal resistance at large temperature differences (70 to 76{degrees}F) was about 35 to 50% less than at small temperature differences. The additional heat flow, attributed to natural convection, was effectively eliminated by applying a covering of fiberglass batts or a combination of a polyethylene film and fiberglass blankets. No significant convection was found either with fiberglass batts or with one type of loose-fill cellulose. Using the experimental data along with an attic model, the additional energy costs due to convection in the coldest climate investigated were estimated to be $0.025/ft{sup 2}yr to $0.028/ft{sup 2}yr at the R-19 level and $0.014/ft{sup 2}yr at the R-38 level. For the same conditions, annual energy savings due to upgrading insulation from the R-19 to the R-38 level were estimated to be $0.046/ft{sup 2}yr to $0.070/ft{sup 2}yr.

  14. Results of R and D for lithium/vanadium breeding blanket design

    SciTech Connect

    Mattas, R.F.; Smith, D.L.; Reed, C.B.; Park, J.H. [Argonne National Lab., IL (United States); Kirillov, I.R. [D.V. Efremov Scientific Research Inst. of Electrophysical Apparatus, St. Petersburg (Russian Federation); Strebkov, Yu.S. [Research and Development Inst. of Power Engineering, Moscow (Russian Federation); Rusanov, A.E. [Inst. of Physics and Power Engineering, Obninsk (Russian Federation); Votinov, S.N. [A.A. Bochvar Inst. of Non-Organic Materials, Moscow (Russian Federation)

    1997-04-01

    The self-cooled lithium/vanadium blanket concept has several attractive features for fusion power systems, including reduced activation, resistance to radiation damage, accommodation of high heat loads and operating to temperatures of 650--700 C. The primary issue associated with the lithium/vanadium concept is the potentially high MHD pressure drop experienced by the lithium as it flows through the high magnetic field of the tokamak. The solution to this issue is to apply a thin insulating coating to the inside of the vanadium alloy to prevent the generation of eddy currents within the structure that are responsible for the high MHD forces and pressure drop. This paper presents progress in the development of an insulator coating that is capable of operating in the severe fusion environment, progress in the fabrication development of vanadium alloys, and a summary of MHD testing. A large number of small scale tests of vanadium alloy specimens coated with CaO and AlN have been conducted in liquid lithium to determine the resistivity and stability of the coating. In-situ measurements in lithium have determined that CaO coatings, {approximately} 5 {micro}m thick, have resistivity times thickness values exceeding 10{sup 6} {Omega}-cm{sup 2}. These results have been used to identify fabrication procedures for coating a large vanadium alloy (V-4Cr-4Ti) test section that was tested in the ALEX (Argonne Liquid metal Experiment) facility. Similar test sections have been produced in both Russia and the US.

  15. Synthesis of Mn3O 4-Based Aerogels and Their Lithium-Storage Abilities.

    PubMed

    Tang, Huang; Sui, Yongxing; Zhu, Xiaoqin; Bao, Zhihao

    2015-12-01

    Mn3O4 aerogels and their graphene nanosheet (GN) composite aerogels were synthesized by a simple supercritical-ethanol process. In the process, supercritical ethanol acted as a reductant to reduce graphene oxide and MnO2 gels simultaneously. The synthesized aerogels consisted of 10-20 nm Mn3O4 nanocrystallites, with BET-specific surface areas around 60 m(2)/g. The performance of the aerogels as anode materials for lithium-ion batteries was also evaluated in this study. The results showed that Mn3O4 aerogels as anode materials exhibited a reversible capacity of 498.7 mAh/g after 60 charge/discharge cycles while the reversible capacity for Mn3O4/GN composite aerogels could further increase to 665 mAh/g. The mechanisms for the enhanced capacity retention could be attributed to their porous structures and improved electronic contact with GN addition. The process should also offer an effective and facile method to fabricate many other porous metal oxide/GN nanocomposites for low-cost, high-capacity, environmentally benign material for lithium-ion batteries. PMID:26061441

  16. Structural and optical characterizations of ZnO aerogel nanopowder synthesized from zinc acetate ethanolic solution

    NASA Astrophysics Data System (ADS)

    Djouadi, D.; Meddouri, M.; Chelouche, A.

    2014-11-01

    ZnO aerogel powder has been synthesized by a modified sol-gel process using zinc acetate ethanolic solution. XRD, SEM, EDAX, FTIR, UV-visible absorption and photoluminescence (PL) techniques have been used to characterize the as-prepared and the annealed ZnO aerogel powders. The as-prepared ZnO powder has a well-defined polycrystalline hexagonal wurtzite structure. This measurement has demonstrated that the lattice parameters are lower than the standard ones indicating that drying in supercritical conditions of ethanol does not affect the crystallinity but acts as a compressive agent. EDAX measurements show that the obtained aerogel contains only O and Zn elements. Annealing improves the crystallinity in the low DRX angles and decreases the crystalline quality in the high diffraction angles. Also, annealing acts as a tensile agent and increases the lattice parameters. FTIR spectra confirm the annealing effect by the apparition of the strong Zn-O vibration band. The ZnO absorption band shifts to lower wave numbers after annealing indicating an increase in the Zn-O bond length and confirms the XRD results. UV-visible results show a decrease of the ZnO aerogel optical band gap after annealing and confirm the thermal decompression effect on the lattice parameters. The photoluminescence measurements show that the annealing of ZnO aerogel favors the thermal generation of zinc interstitials and oxygen vacancies defects existing in the as-prepared zinc oxide aerogel and shifts the emission toward lower energies.

  17. Room-temperature embedment of anatase titania nanoparticles into porous cellulose aerogels

    NASA Astrophysics Data System (ADS)

    Jiao, Yue; Wan, Caichao; Li, Jian

    2015-07-01

    In this paper, a facile easy method for room-temperature embedment of anatase titania (TiO2) nanoparticles into porous cellulose aerogels was reported. The obtained anatase TiO2/cellulose (ATC) aerogels were characterized by scanning electron microscopy, energy-dispersive X-ray spectrometer, transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, nitrogen adsorption measurements, and thermogravimetric analysis. The results showed that high-purity anatase TiO2 nanoparticles with sizes of 3.69 ± 0.77 nm were evenly dispersed in the cellulose aerogels, which leaded to the significant improvement in specific surface area and pore volume of ATC aerogels. Meanwhile, the hybrid ATC aerogels also had a high loading content of TiO2 (ca. 17.7 %). Furthermore, through a simple photocatalytic degradation test of indigo carmine dye under UV light, ATC aerogels exhibited superior photocatalytic activity and shape stability, which might be useful in some fields like governance of water pollution, and chemical leaks.

  18. Rapid extraction of dust impact tracks from silica aerogel by ultrasonic microblades

    NASA Astrophysics Data System (ADS)

    Ishii, H. A.; Graham, G. A.; Kearsley, A. T.; Grant, P. G.; Snead, C. J.; Bradley, J. P.

    2005-11-01

    In January 2006, NASA's Stardust mission will return with its valuable cargo of the first cometary dust particles captured at hypervelocity speeds in silica aerogel collectors and brought back to Earth. Aerogel, a proven capture medium, is also a candidate for future sample return missions and low-Earth orbit (LEO) deployments. Critical to the science return of Stardust as well as future missions that will use aerogel is the ability to efficiently extract impacted particles from collector tiles. Researchers will be eager to obtain Stardust samples as quickly as possible; tools for the rapid extraction of particle impact tracks that require little construction, training, or investment would be an attractive asset. To this end, we have experimented with diamond and steel microblades. Applying ultrasonic frequency oscillations to these microblades via a piezo-driven holder produces rapid, clean cuts in the aerogel with minimal damage to the surrounding collector tile. With this approach, intact impact tracks and associated particles in aerogel fragments with low-roughness cut surfaces have been extracted from aerogel tiles flown on NASA's Orbital Debris Collector (ODC) experiment. The smooth surfaces produced during cutting reduce imaging artifacts during analysis by scanning electron microscopy (SEM). Some tracks have been dissected to expose the main cavity for eventual isolation of individual impact debris particles and further analysis using techniques such as transmission electron microscopy (TEM) and nano-secondary ion mass spectrometry (nanoSIMS).

  19. Blanket design considerations for fast reactor oxide fuel systems based on CRBRP experience

    SciTech Connect

    Garkisch, H.D.

    1980-01-01

    The blanket assemblies are of prime importance in achieving the performance goals of fast reactor fuel systems to conserve uranium ore and to minimize fuel cycle costs. The purpose of past blanket design efforts in the US was to meet these goals with designs of optimum fuel and thermal performance. Only the Clinch River Breeder Reactor Plant (CRBRP) blanket design has evolved beyond the conceptual stage. The CRBRP blanket assembly design is based on conservatively predicted environments and criteria which are being confirmed by a design oriented development program. The results of the ongoing program obtained to date have not indicated any need for assembly design changes. However, since the irradiation testing of blanket rods is not completed, the ultimate performance capability of the blanket is presently not known. Therefore, conservative blanket assembly design criteria and predicted environments must be utilized for performance predictions at the present time.

  20. Surface Plasmon Resonance Evaluation of Colloidal Metal Aerogel Filters

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

    We have fabricated aerogels containing gold, silver, and platinum nanoparticles for gas catalysis applications. By applying the concept of an average or effective dielectric constant to the heterogeneous interlayer surrounding each particle, we extend the technique of immersion spectroscopy to porous or heterogeneous media. Specifically, we apply the predominant effective medium theories for the determination of the average fractional composition of each component in this inhomogeneous layer. Hence, the surface area of metal available for catalytic gas reaction is determined. The technique is satisfactory for statistically random metal particle distributions but needs further modification for aggregated or surfactant modified systems. Additionally, the kinetics suggest that collective particle interactions in coagulated clusters are perturbed during silica gelation resulting in a change in the aggregate geometry.